• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:

    公开号:SE533997C2
    申请号:SE0950589
    申请日:2008-02-21
    公开日:2011-03-22
    发明作者:Atsushi Shirao；Masanori Ikari
    申请人:Komatsu Mfg Co Ltd；
    IPC主号:
    专利说明:

    533 997 2 DESCRIPTION OF THE INVENTION In a construction vehicle, such as that described above, however, the pump displacement changes rapidly, and the wheels may slip or the vehicle may suddenly accelerate. For example, there may be times when the construction vehicle remains stationary, and cannot move forward, due to a large load when the vehicle is plowing snow or sediment. In this condition, assuming that the driver keeps the accelerator pedal fully depressed, the engine speed will therefore be maintained at maximum rotational speed. In this case, since the oil pressure in the primary circuit has increased, the oil pressure limiting component acts to reduce the oil pressure in the primary circuit. At this time, the pump displacement and the oil pressure in the primary circuit reach the point Px1 in Fig. 14. In this state, the oil pressure in the primary circuit decreases as the load acting on the construction vehicle from the snow or sediment decreases. With the oil pressure characteristics of the pump displacement primary circuit, such as those shown by the solid line L11, the pump displacement and the oil pressure in the primary circuit change from the point Px1 to the point Px2, and the pump displacement thus changes rapidly from Qx1 to Qx2. Therefore, the wheels may slip or the construction vehicle may suddenly accelerate.
    An object of the present invention is to provide a construction vehicle in which it is possible to minimize wheel slip and sudden acceleration.
    The construction vehicle according to a first aspect of the present invention comprises an engine, a transport hydraulic pump, a transport hydraulic circuit, a transport hydraulic motor, a transport wheel, a hydraulic pump for work equipment, a work equipment, a control unit, and an oil pressure limiting component. The transport hydraulic pump is a hydraulic pump, which is driven by the motor. The transport hydraulic circuit is a circuit through which pressure oil flows, which is discharged from the transport hydraulic pump. The transport hydraulic motor is a hydraulic motor driven by the oil pressure provided by the transport hydraulic circuit. The transport wheel is driven by the driving force from the transport hydraulic motor. The hydraulic pump for the work equipment is a hydraulic pump, which is driven by the motor. The work equipment is powered by the pressure oil, which is discharged from the hydraulic pump for the work equipment. The control unit controls the engine speed, the displacement of the transport hydraulic pump, and the displacement of the transport hydraulic motor, to control the vehicle speed and the drive wheel force. The oil pressure limiting component limits the pressure of the transport circuit so as not to 533 99 3 exceed a predetermined limiting pressure value, the transport circuit pressure being the pressure of the pressure oil flowing through the transport hydraulic circuit. The control unit can implement a suppressive control of a rapid change in the pump displacement of the transport hydraulic pump, so that the transport circuit pressure reaches a maximum value equal to or less than the limit pressure value when the vehicle has stopped, regardless of engine speed, and the transport hydraulic pump displacement gradually increases - the port circuit pressure decreases from the maximum value. In this construction vehicle, the suppressive control of a rapid change of the pump displacement results in oil pressure characteristics in the pump displacement primary circuit, in which the transport circuit pressure gradually changes in accordance with changes in the oil pressure in the primary circuit, without the effect of the oil pressure limiting component. In this construction vehicle, rapid changes in the pump displacement can thus be suppressed, and wheel slip and sudden acceleration can also be suppressed.
    With this suppressive control of a rapid change of the pump displacement, since the displacement of the transport hydraulic pump is controlled, the danger of affecting the output speed of other hydraulic pumps, for example the hydraulic pump for the work equipment, is less than in cases where the engine speed is limited. Therefore, reductions in the drive speed of the work equipment can be suppressed while the suppressive control of a rapid change of the pump displacement is implemented.
    The construction vehicle according to a second aspect of the present invention comprises an engine, a transport hydraulic pump, a transport hydraulic circuit, a transport hydraulic motor, a transport wheel, a hydraulic pump for work equipment, a work equipment, a control unit, and an oil pressure limiting component. The transport hydraulic pump is a hydraulic pump, which is driven by the motor. The transport hydraulic circuit is a circuit through which pressure oil flows, which is discharged from the transport hydraulic pump. The transport hydraulic motor is a hydraulic motor driven by the oil pressure provided by the transport hydraulic circuit. The transport wheel is driven by the driving force from the transport hydraulic motor. The hydraulic pump for the work equipment is a hydraulic pump, which is driven by the motor. The work equipment is powered by the pressure oil, which is discharged from the hydraulic pump for the work equipment. The control unit controls the engine speed, the displacement of the transport hydraulic pump, and the displacement of the transport hydraulic motor, to control the vehicle speed and the drive wheel force. The oil pressure limiting component limits the pressure of the transport circuit so as not to exceed a predetermined limiting pressure value, the transport circuit pressure being the pressure of the pressure oil flowing through the transport hydraulic circuit. The control unit can implement a suppressive control of a rapid change of the pump displacement to control the displacement of the transport hydraulic pump so that the displacement of the transport hydraulic pump gradually decreases when the transport circuit pressure increases, and the transport circuit pressure reaches a maximum value equal to or less than the limiting pressure value. In this construction vehicle, the implementation of a suppressive control results in a rapid change of the pump displacement in oil pressure characteristics of the pump displacement primary circuit, wherein the transport circuit pressure gradually changes in accordance with changes in the oil pressure in the primary circuit, without the effect of the oil pressure limiting component. In this construction vehicle, rapid changes in the pump displacement can thus be suppressed, and wheel slip and sudden acceleration can also be suppressed.
    With this suppressive control of a rapid change of the pump displacement, since the displacement of the transport hydraulic pump is controlled, the danger of affecting the output flow rate of other hydraulic pumps, for example the hydraulic pump for the work equipment, is less than in cases where the engine speed is limited. Therefore, reductions in the drive speed of the work equipment can be suppressed while the suppressive control of a rapid change of the pump displacement is implemented.
    The construction vehicle according to a third aspect of the present invention is the construction vehicle according to the first and second aspects, which further comprises a transport circuit pressure detector for detecting the transport circuit pressure, and an engine speed detector for detecting the engine speed. The control unit controls the displacement of the transport hydraulic pump during the suppressive control of a rapid change of the pump displacement on the basis of the transport circuit pressure, which is detected by the transport circuit pressure detector and the engine speed, which is detected by the engine speed detector. In this construction vehicle, the desired oil pressure characteristic of the pump displacement primary circuit can be obtained by controlling the displacement of the transport hydraulic pump on the basis of the transport circuit pressure detected by the transport circuit pressure detector and the engine speed detected by the engine speed detector. The suppressive control of a rapid change of the pump displacement described above can thus be easily implemented.
    The construction vehicle according to a fourth aspect of the present invention is the construction vehicle according to the first and second aspects, which further comprises a vehicle speed detector for detecting the vehicle speed, and an engine speed detector for detecting the engine speed. The control unit controls the displacement of the transport hydraulic pump on the basis of the vehicle speed, which is detected by the vehicle speed detector and the engine speed is detected by the engine speed detector during the suppressive control of a rapid change of the pump displacement. In this construction vehicle, the displacement of the transport hydraulic pump is controlled on the basis of the vehicle speed, which is detected by the vehicle speed detector and the engine speed is detected by the engine speed detector. led vehicle that has a mechanism where the displacement of the transport hydraulic pump decreases as the transport circuit pressure increases, the vehicle speed is a parameter that is correlated with the transport circuit pressure during the conditions when the transport hydraulic motor displacement is constant and the engine speed is constant.
    Therefore, the preferred oil pressure characteristic of the pump displacement primary circuit can also be obtained by controlling the displacement of the transport hydraulic pump in the light of the vehicle speed and the engine speed. The suppressive control of a rapid change of the pump displacement described above can thus be easily implemented.
    The construction vehicle according to a fifth aspect of the present invention is the construction vehicle according to the first and second aspects, which comprises an electromagnetic proportional control valve, which can control the displacement of the transport hydraulic pump. The control unit controls the displacement of the transport hydraulic pump by electrically controlling the electromagnetic proportional control valve.
    In this construction vehicle, the control unit electrically controls the electromagnetic proportional control valve, and can thus control the displacement of the transport hydraulic pump. With this construction vehicle, the displacement of the transport hydraulic pump can thus be controlled to obtain the desired oil pressure characteristic of the pump displacement primary circuit, 533 997 6 and the suppressive control of a rapid change of the pump displacement can thus be easily performed.
    The construction vehicle according to a sixth aspect of the present invention is the construction vehicle according to the first or the second aspect, which further comprises a pump displacement control mechanism for varying the displacement of the transport hydraulic pump according to the supplied pilot pressure, and a pressure control valve, which can control the pilot pressure supplied pump deployment control mechanism. The control unit controls the displacement of the transport hydraulic pump by electrically controlling the pressure control valve.
    In this construction vehicle, the control unit controls the pressure control valve electrically, and can thus control the displacement of the transport hydraulic pump. With this construction vehicle, the displacement of the transport hydraulic pump can thus be controlled to obtain the desired oil pressure characteristic of the pump displacement primary circuit, and the suppressive control of a rapid change of the pump displacement can thus be easily carried out.
    The construction vehicle according to a seventh aspect of the present invention is the construction vehicle according to the first or the second aspect, wherein the control unit controls the displacement of the transport hydraulic pump while suppressing a rapid change of the pump displacement so that the maximum driving force of the vehicle speed-driving speed characteristic becomes lower. than the maximum drive wheel force in the vehicle speed drive wheel force characteristic in cases in which the suppressive control of a rapid change of the pump displacement is not performed. In a conventional construction vehicle, the drive wheel force does not assume an extreme value when the vehicle speed is zero, but when the vehicle speed is in a low speed range, as in the vehicle speed drive wheel force characteristic shown in Fig. 15. In this case, the drive wheel force increases according to an increase of the vehicle speed at a certain speed or less, and the drive wheel force then decreases in accordance with an increase in the vehicle speed at a certain speed or greater, which makes the vehicle more difficult for the driver to handle. 533 997 7 In the construction vehicle according to the seventh aspect of the present invention, however, under the suppressive control of a rapid change of the pump displacement, the maximum drive wheel force of the vehicle speed-drive force characteristic arises at a lower speed than the maximum drive wheel force at the vehicle wheel speed characteristics. suppressive control of a rapid change of the pump displacement is not carried out. Therefore, the vehicle speed driving force characteristic under suppressive control of a rapid change of the pump displacement is closer than monotonic reduction function in which the driving force gradually decreases in accordance with the increase of the vehicle speed, a vehicle speed driving force characteristic in case of rapid suppression of pumping. . The construction vehicle according to an eighth aspect of the present invention is the construction vehicle according to the first or the second aspect, which further comprises a selector to allow a driver to select the implementation of suppressive control of a rapid change of the pump displacement. In this construction vehicle, the driver can arbitrarily choose whether to suppress control of a rapid change of the pump displacement by activating the selector. For example, the suppressive control of a rapid change of pump displacement can be selected for transport on snow-covered roads or other low-friction road surfaces, and the suppressive control of a rapid change of the pump displacement can be opted out when transporting over normal road surfaces. 533 997 8 BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view of the construction vehicle; Fig. 2 is a schematic view showing the construction of the hydraulic drive mechanism according to the first embodiment; Fig. 3 is a block diagram of the construction vehicle; Fig. 4 is a graph showing an example of data on oil pressure characteristics of pump displacement primary circuit; Fig. 5 is a graph showing an example of data on oil pressure characteristics of engine displacement primary circuit; Fig. 6 is a graph showing characteristics of vehicle speed-drive wheel force; Fig. 7 is a graph showing oil pressure characteristic data of pump displacement primary circuit for each engine speed under suppressive control of a rapid change of pump displacement; Fig. 8 is a drawing showing the construction of the hydraulic drive mechanism according to the second embodiment; Fig. 9 is a graph showing data on engine speed pilot pressure characteristics for each vehicle speed under suppressive control of a rapid change of pump displacement; Fig. 10 is a graph showing the oil pressure characteristics of the pump displacement primary circuit for each engine speed under suppressive control of a rapid change of pump displacement; Fig. 11 is a drawing showing the construction of a hydraulic drive mechanism in accordance with another embodiment; Fig. 12 is a drawing showing the construction of a hydraulic drive mechanism in accordance with another embodiment; Fig. 13 is a drawing showing the construction of a hydraulic drive mechanism according to another embodiment; Fig. 14 is a graph showing the oil pressure characteristics of the engine displacement primary circuit of a conventional construction vehicle; and Fig. 15 is a graph showing characteristics of vehicle speed-drive wheel power of a conventional construction vehicle. 533 997 9 NOTE 1 Construction vehicles 3 Work equipment 4a, 4b Transport wheels 8 Engine 9 Transport hydraulic pump 11 Hydraulic pump for work equipment 12 Transport hydraulic motor 16 Control unit 19 Engine speed detector 20, 21 Primary circuits (transport hydraulic circuits) 22 Pump pressure sensor pump displacement) 24 Control valve for pump displacement (electromagnetic proportional control valve) 28 Decompression valve (pressure control valve) 31 Limit valve (oil pressure limiting component) 34 Vehicle speed detector 36 Other selectors (selector) an embodiment of the present invention is shown in Figs. The construction vehicle 1 is a wheel loader, which can be propelled by means of tires 4a, 4b, and can also use a work equipment 3 to perform the desired work.
    The construction vehicle 1 comprises a vehicle frame 2, a work equipment 3, tires 4a, 4b, and a cab 5. The vehicle frame 2 has a front frame 2a arranged at the front and a rear frame 2b arranged at the rear, and the front frame 2a and the the rear frame 2b are interconnected in the middle of the vehicle frame 2 and can turn right and left.
    The work equipment 3 and a pair of front wheels 4a are attached to the front frame 2a. The work equipment 3 is a device, which is driven by pressure oil from a hydraulic pump 11 for the work equipment (see Fig. 2), and the work equipment has a lifting arm 37 mounted at the front portion of the front frame 2a, a bucket 38 attached to the outer end of the lifting arm 37, and a cylinder 26 for the work equipment (see Fig. 2) for driving these components. The pair of front wheels 4a are arranged on the side surfaces of the front frame 2a.
    The cab 5, a pair of rear wheels 4b, and other components are arranged at the rear frame 2b. The cab 5 is located at the upper portion of the vehicle frame 2, and inside the cab is a steering wheel installed, an accelerator pedal, and other operating components; a display unit for displaying the vehicle speed and other varying information, a driver's seat, and the like. The pair of rear wheels 4b are arranged on side surfaces of the vehicle frame 2b. A hydraulic fluid tank (not shown) is provided on the right side of the rear frame 2b. and the hydraulic fluid tank houses the hydraulic fl uid, which is pressurized by various hydraulic pumps.
    A hydraulic drive mechanism 7a for driving the tires 4a, 4b and the work equipment 3 is installed on the vehicle frame 2. The construction of the hydraulic drive mechanism 7a is described in the following with reference to Fig. 2.
    The hydraulic drive mechanism 7a primarily has a motor 8, a transport hydraulic pump 9, a charge pump 10, the hydraulic pump 11 for the work equipment, a transport hydraulic motor 12, a drive shaft 15, a control unit 16 (see Fig. 3), and uses a so-called HST system . 533 997 ll The engine 8 is a diesel engine, and the output torque generated by the engine 8 is transmitted to the transport hydraulic pump 9, the charge pump 10, the hydraulic pump 11 for the work equipment, a steering hydraulic pump (not shown), and other components. The engine 8 is equipped with a fuel injector 17 to control the output torque and the rotational speed of the engine 8, and the fuel injector adjusts a guide value for the engine speed according to how much the accelerator pedal is activated (hereinafter referred to as "accelerator pedal position") and adjusts the amount of fuel injected.
    The accelerator pedal is a means for indicating the target speed of the engine 8, and is provided with a position detector 18 for the accelerator pedal (see Fig. 3). The position detector 18 for the accelerator pedal is constructed of a potentiometer or the like, and the position detector for the accelerator pedal detects the position of the accelerator pedal. The accelerator position detector 18 sends a position signal indicating the position of the accelerator pedal to the control unit 16, and a control signal is output from the control unit 16 to the fuel injector 17. Therefore, the driver can control the engine 8 speed by adjusting how much the accelerator pedal is affected. The motor 8 is also provided with an engine speed detector 19 (see Fig. 3), which is composed of a speed sensor for detecting the actual speed of the engine 8, and a speed signal from the engine speed detector 19 is input to the control unit 16.
    The transport hydraulic pump 9 is a variable displacement hydraulic pump, which can vary the displacement by varying the angle of inclination of a rocker disc, and is driven by the engine 8. Pressure oil discharged from the transport hydraulic pump 9 is led to the transport hydraulic motor 12 through primary circuits 20, 21. with an oil pressure detector 22 for the primary circuit (transport circuit pressure detector) (see Fig. 3) for detecting the pressure (hereinafter referred to as "oil pressure for the primary circuit") of the pressure oil passing through the primary circuits 20, 21. The oil pressure of the primary circuit (transport circuit pressure) the driving oil pressure of the pressure oil to drive the transport hydraulic motor 12. A control cylinder 23 for the pump displacement is connected to the transport hydraulic pump 9 and a pump displacement control valve 24 can vary the inclination angle of the rocker plate of the transport hydraulic pump 9. The pump displacement control valve 24 has a link unit 24 with the cylinder unit 23a of the control cylinder 23 for the pump displacement, and can control, as required, the position of the cylinder unit 23a against a control signal from the control unit 16. Specifically, the control valve 24 for the pump displacement is an electromagnetically proportional control valve for controlling the control cylinder 23 for the pump displacement against the background of a control signal from the control unit 16, and can switch the direction of the oil supplied to the control cylinder 23 for the pump displacement as well as vary the inclination angle of the rocker plate of the transport hydraulic pump 9. Therefore, the control unit 16 can vary the displacement of the transport hydraulic pump 9 by electrically controlling the control valve 24 for the pump displacement.
    The charge pump 10 is driven by the motor 8 and can provide pressure oil to drive the control cylinder 23 for the pump displacement to the control valve 24 for the pump displacement.
    The charge pump 10 also provides pressure oil to drive an engine cylinder 29 to an engine control valve 30.
    A restriction circuit 39, which is connected to a restriction valve 31, is also connected to a circuit for supplying pressure oil from the charge pump 10 to the control cylinder 23 for the pump displacement. The limit valve 31 is a decompression valve which can reduce the pilot pressure of the control cylinder 23 for the pump displacement to a set pressure via the balance between fi force and the force of the oil pressure of the primary circuit. The limit valve 31 is designed to reduce the pilot pressure provided to the control cylinder 23 for the pump displacement in cases where the oil pressure of the primary circuit has become equal to or greater than a set limit pressure, and to limit the oil pressure of the primary circuit so as not to exceed the limit pressure value.
    The hydraulic pump 11 for the work equipment is driven by the engine 8, whereby pressure oil discharged from the hydraulic pump 11 for the work equipment is fed to the work equipment cylinder 16 of the work equipment 3 via a hydraulic circuit 25 for the work equipment, so that the work equipment cylinder 26 is driven.
    The transport hydraulic motor 12 is a variable displacement hydraulic motor, which can vary the displacement by varying the angle of inclination of an angled shaft, and is driven by the pressure oil discharged from the transport hydraulic pump 9 to generate a driving force for transport. The transport hydraulic motor 12 is provided with a motor cylinder 29 for controlling the inclination angle of the transport hydraulic motor 12, and a motor control valve 30 (see Fig. 3) for controlling the motor cylinder 29. The motor control valve 30 is an electromagnetic control valve which is controlled by a control signal from the control unit 16. and the displacement of the transport hydraulic motor 12 can be varied by controlling the motor cylinder 29. 533 997 13 The drive shaft 15 causes the tires 4a, 4b to rotate by transmitting the driving force from the transport hydraulic motor 12 to the tires 4a, 4b (see Fig. 1). The drive shaft 15 is also provided with a vehicle speed detector 34 (see Fig. 3), which is composed of a vehicle speed sensor for detecting the vehicle speed from the rotational speed of the drive shaft 15, and a vehicle speed signal from a vehicle speed detector 34 is input to the control unit 16.
    The control unit 16 controls the control valves and the fuel injection device 17 electronically in the light of output signals from the detectors, and the control unit can control the engine speed, the displacement of the hydraulic pumps 9 to 11, the displacement of the transport hydraulic motor 12, and other factors. By, for example, electrically controlling the control valve 24 for the pump displacement, the control unit 16 can control the displacement of the transport hydraulic pump 9. The drive wheel force and vehicle speed vary accordingly in the construction vehicle 1, and the vehicle speed can be automatically changed from zero to the maximum vehicle speed without a speed-changing operation (see Fig. 6). The construction vehicle 1 comprises a first selector 35, and the operation of the first selector 35 by a driver causes the control unit 16 to implement limiting control for the drive wheel force in order to limit the maximum drive wheel force. The construction vehicle 1 also comprises a second selector 36, and the operation of the second selector 36 by a driver causes the control unit 16 to implement suppressive control of a rapid change of the pump displacement. Transport control of the construction vehicle 1 is described in detail in the following.
    The control unit 16 processes the output signals from the engine speed detector 19 and the oil pressure detector 22 for the primary circuit and outputs directive signals regarding the pump displacement to the control valve 24 for the pump displacement. The control unit 16 refers to the oil pressure characteristic data for the pump displacement primary circuit, which is stored in the control unit 16, sets the pump displacement from the value of the engine speed and the value of the oil pressure of the primary circuit, and outputs a directive value for the pump displacement set to the control valve displacement 24 for the pump displacement.
    The use of "pump displacement" is referred to below as the displacement of the transport hydraulic pump 9. Fig. 4 shows an example of data for oil pressure characteristics of 533 997 14 pump displacement primary circuit. The solid line L11 and the dashed lines L12 to L15 in the diagram are lines showing oil pressure characteristics of the pump displacement primary circuit (hereinafter referred to as "PQ characteristics"), which vary according to the engine speed. The control valve 24 for the pump displacement varies the angle of inclination of the transport hydraulic pump 9 by controlling the control cylinder 23 for the pump displacement in the light of the entered direct value for the pump displacement. The pump displacement is thereby controlled to correspond to the engine speed.
    The controller 16 also processes output signals from the engine speed detector 19 and the primary pressure oil pressure detector 22 and outputs a directive directive for the engine displacement to the engine control valve 30. The controller 16 refers to the oil displacement characteristics of the engine displacement primary circuit stored in the engine controller 16. from the value of the engine speed and the value of the oil pressure of the primary circuit, and outputs an inclination angle change instruction corresponding to the set engine displacement to the engine control valve 30. Fig. 5 shows an example of oil pressure characteristic data of the engine displacement primary circuit. The solid line L21 in the diagram is a line at which the angle of inclination in relation to the oil pressure of the primary circuit is established, when the engine speed is at a certain speed. The inclination angle is at a minimum (min) while the oil pressure of the primary circuit is at a specific value or less, the inclination angle gradually increasing (the inclined portion L22 of the solid line) when the oil pressure of the primary circuit increases, and after the inclination angle has reached a maximum ( max), the angle of inclination remains at the maximum angle of inclination Max even if the oil pressure increases. The inclined portion L22 of the solid line is set to increase or decrease in accordance with the engine speed. Specifically, if the engine speed is low, the angle of inclination increases from a state of low oil pressure of the primary circuit, and the angle of inclination is controlled to reach the maximum angle of inclination in a state of less oil pressure of the primary circuit (reference to the inclined portion L23 of the lower dashed line). Fig. 5). Conversely, if the engine height / number is high, the tilt angle remains at the minimum tilt angle Min until the oil pressure of the primary circuit increases further, and the tilt angle is controlled to reach the maximum tilt angle Max in a state of higher oil pressure of the primary circuit (reference to the inclined portion L24 of the upper dashed line in Fig. 5). 533 997 The control unit 16 switches the maximum value of the angle of inclination of the transport hydraulic motor 12 in the light of an output signal from the first selector 35 and limits the maximum displacement of the transport hydraulic motor 12 to a predetermined limited value, so as to limit the maximum drive wheel force. . In the construction vehicle 1, the first selector 35 can be switched between a switched-on state and a switched-off state. The maximum drive wheel force in the on state can be varied between three levels: level A, level B, and level C. When the first selector 35 is in the off state, the maximum tilt angle is at the maximum position in Fig. 5, and the characteristics of vehicle speed-drive wheel force in this state is represented by the graph L1 in Fig. 6. This maximum tilt angle Max is a maximum value for the performance of the transport hydraulic motor 12. When the first selector 35 is turned to the on position, the maximum tilt angle changes to a value, which corresponds to the level of the set maximum drive wheel force. Specifically, when the maximum drive wheel force at the specified condition is set to level A, the maximum tilt angle changes to Ma. Similarly, when the maximum drive wheel angle is set to level B, the maximum tilt angle changes to Mb, and when the maximum drive wheel force is set to level C, the maximum tilt angle changes to Mc. Thus, the maximum angle of inclination changes to Ma, Mb, and Mc, which are less than Max, resulting in the characteristic of vehicle speed-drive wheel force, in which the maximum drive-wheel force has decreased, as in graphs La, Lb, and Lc in Figs. 6. It is thereby possible to suppress the drive wheel force of the tires 4a, 4b to prevent slipping, even when the accelerator pedal position is set to max in order to ensure a workload performed by the work equipment 3 on soft roadways, snow-covered roadways, and other roadways which have low friction, or in cases where the weight of the assembled objects is relatively low. Graphs L1, La, Lb, and Lc all represent the characteristics of vehicle speed-drive wheel power in a state when the accelerator pedal position is fully engaged.
    The control unit 16 can implement suppressive control of a rapid change of pump displacement in the light of the output from the second selector 36. Suppressive control of a rapid change of the pump displacement is performed to control 533 99 16 the pump displacement of the transport hydraulic pump 9, so that the displacement of the transport hydraulic pump 9 gradually changes in accordance with the change of the oil pressure of the primary circuit while the oil pressure of the primary circuit is limited so as not to exceed the restriction pressure valve.
    Under suppressive control of a rapid change of the pump displacement, the control unit 16 determines the displacement of the transport hydraulic pump 9 against the graph shown in Fig. 7. In this graph, the displacement of the transport hydraulic pump 9 has been determined in relation to the oil pressure of the primary circuit, and the lines L11 'to L15' show data for PQ characteristics, which vary according to the engine speed. Taking into account the engine speeds, sequentially in relation to the lines L11 'to L15' at N1, N2, N3, N4, N5, the speeds have the ratio N1> N2> N3> N4> N5. Data for the PQ characteristic shown in Fig. 7 are used where suppressive control of a rapid change of the pump displacement has been used, and there are also characteristics which differ from data on the PQ characteristic L11 to L15 (reference to double-dashed lines) in cases where suppressive control of a rapid change in pump displacement has not been selected. Reference symbols, which belong to the data for PQ characteristics, which have the same number, represent the same engine speed. For example, lines L11 and L11 'represent data for PQ characteristics at the same engine speed, and differ or not, depending on whether suppressive control of a rapid change in pump displacement has been selected. The control unit 16 controls the displacement of the transport hydraulic pump 9 in the light of the oil pressure of the primary circuit detected by the oil pressure detector 22 of the primary circuit, the engine speed detected by the engine speed detector 19, and their data on PQ characteristics.
    Specifically, in the PQ characteristic data shown in Fig. 7, the oil pressure of the primary circuit reaches a maximum value equal to or less than the limiting pressure value Plt when the vehicle has stopped, and the displacement of the transport hydraulic pump 9 gradually increases when the oil pressure of the primary circuit decreases from the maximum value. In other words, the displacement of the transport hydraulic pump 9 gradually decreases as the oil pressure of the primary circuit increases, and the oil pressure of the primary circuit reaches a maximum value equal to or less than the limit pressure value Plt when the vehicle has stopped. Therefore, data on PQ characteristics L11 'to L14' where suppressive control of a rapid change of the pump displacement is chosen are different from data on PQ characteristics L11 to L14 in cases 533 997 17 where suppressive control of a rapid change of the pump displacement is not has been selected. Specifically, for data on PQ characteristics L11 to L15, where where suppressive control of a rapid change of the pump displacement has not been selected, data on PQ characteristics L11, L12, corresponding to engine speeds equal to or greater than one predetermined rotational speed a horizontal line Lhz, in which the oil pressure of the primary circuit does not change even if the pump displacement does not change. In this portion, the oil pressure of the primary circuit remains constant at the limiting pressure value Plt and the oil pressure of the primary circuit does not change even if the pump displacement does not change. This occurs because the limiting circuit acts, which suppresses increases in the oil pressure of the primary circuit and maintains a constant oil pressure of the primary circuit at the limiting pressure value Plt. With data on PQ characteristics L11 ', L12', which are used where suppressive control of a rapid change of the pump displacement has been selected, no such predetermined horizontal line occurs independent of the engine speed, and the pump displacement changes gradually in accordance with changes in the oil pressure. at the primary circuit. For data on PQ characteristics L11 'to L15', - where suppressive control of a rapid change of the pump displacement has been selected, data on PQ characteristics L15 'is in the case for a relatively low engine speed, the same as data on PQ characteristics if where suppressive control of a rapid change of the pump displacement has not been selected.
    During a suppressive control of a rapid change of the pump displacement, as described above, the displacement of the transport hydraulic pump 9 is controlled so that the oil pressure of the primary circuit and the pump displacement change along the lines shown by the PQ characteristic L11 'to L15' in Fig. 7. The characteristic of vehicle speed - drive wheel force, which is shown by the graph L2 in Fig. 6 is thereby obtained. This characteristic of vehicle speed-drive wheel force is similar to the characteristic of vehicle speed-drive wheel force of a vehicle equipped with a torque converter (reference to graph L3). Characteristics of vehicle speed-drive wheel force of a vehicle equipped with a torque converter constitute a monotonically decreasing function, and the maximum drive wheel force reaches a maximum at the time when the vehicle speed is zero. Graph Lc represents the characteristic of vehicle speed-drive wheel force when level C for limiting control of the drive wheel force is performed but when suppressive control of a rapid change of the pump displacement is not performed (an accelerator pedal position of 100%).
    Graph L2 represents characteristics of vehicle speed-drive wheel force when suppressive control of a rapid change of the pump displacement has been performed together with level C for limiting control of the drive wheel force. In this graph L2, the maximum drive wheel force that occurs at a lower speed than the maximum drive wheel force is shown in the vehicle speed-drive force characteristic shown by the graph Lc. Specifically, the vehicle speed V1, where maximum drive wheel force arises in the characteristic of vehicle speed-drive force when suppressing control of a rapid change of the pump displacement is less than the vehicle speed V2 where the maximum drive wheel force arises in the characteristic of vehicle speed-driving force (reference to driving force). rapid change in pump displacement does not occur, for example at 1 km / h.
    Suppressive control of a rapid change of the pump displacement can also be performed along level B or level A for limiting control of the drive wheel force, instead of level C for limiting control of the drive wheel force.
    The control unit 16 terminates suppressive control of a rapid change of the pump displacement in case the second selector 36 has been switched off. (1) In the construction vehicle 1, under suppressive control of a rapid change of the pump displacement, conditions are suppressed in which the oil pressure of the primary circuit does not change even if the pump displacement changes, since the control valve 24 for the pump displacement is controlled so that the displacement of the transport hydraulic pump 9 in accordance with changes in the oil pressure of the primary circuit.
    Therefore, rapid changes in the pump displacement are suppressed. Rapid accelerations and the occurrence of slippage on roads with low friction can thus be reduced.
    Vehicle speed-drive force characteristics Similar to vehicle speed-drive force characteristics of a vehicle equipped with a torque converter can be obtained by controlling the pump displacement control valve 24 as described above. Since a vehicle equipped with a torque converter has a linear characteristic of vehicle speed-drive wheel force in which the drive wheel force reaches a maximum at a vehicle speed at zero and the drive wheel force decreases in accordance with the increase of the vehicle speed, obtaining similar characteristics for vehicle speed-drive wheel power makes it possible for a driver to easily carry out transport operations. (2) In the construction vehicle 1, since the displacement of the transport hydraulic pump 9 is controlled under suppressive control of a rapid change of the pump displacement, there is a small danger of affecting the displacement of other hydraulic pumps, for example of the hydraulic pump 11 for work equipment, compared with cases 8 is limited. Therefore, it is possible to suppress decreases in drive speed of the work equipment 3 while suppressing control of a rapid change of the pump displacement is implemented.
    (Second embodiment) Fig. 8 shows the configuration of a hydraulic drive mechanism 7b of a construction vehicle 1 according to the second embodiment of the present invention.
    In this hydraulic drive mechanism 7b, which is connected to the transport hydraulic pump 9, a directional valve 24 and a control cylinder 23 for the pump displacement can vary the inclination angle of the rocker disk of the transport hydraulic pump 9. The control cylinder 23 for the pump displacement functions as a control mechanism for the pump displacement of the transport hydraulic pump 9 by varying the angle of inclination of the pulley of the transport hydraulic pump 9 according to the pilot pressure provided. The directional valve 24 is an electromagnetic control valve for controlling the direction of pressure oil provided by the control cylinder 23 for pump displacement in the light of a control signal from the control unit 16. The action of the directional valve 24 enables the construction vehicle 1 to switch between forward and reverse transport. A vehicle speed control valve 32 is provided on the circuit to supply pressure oil from the charge pump 10 to the pump displacement control cylinder 23. The vehicle speed control valve 32 is an electromagnetic, proportional pressure control valve which can control, as required, the pilot pressure provided by the pump displacement control cylinder 23 in accordance with a control signal from the control unit 16. The vehicle speed control valve 32 can vary the displacement of the transport hydraulic pump. 9 by controlling the pilot pressure provided by the control cylinder 23 for the pump displacement.
    As described above, the control unit 16 controls the vehicle speed control valve 32 in the hydraulic drive mechanism 7b and controls the pilot pressure provided by the pump displacement control cylinder 23, whereby the displacement of the transport hydraulic pump 9 can be varied as required.
    In addition, the configuration is similar to that of the construction vehicle of the first embodiment.
    In the following, control of the transport hydraulic pump 9 and the transport hydraulic motor 12 in this construction vehicle will be described.
    The control unit 16 outputs a directive signal for the pump displacement to the control valve 32 for vehicle speed in accordance with the engine speed and the oil pressure of the primary circuit. With reference to the engine speed-pilot pressure data stored in the control unit 16, the control unit 16 sets the pump displacement from the engine speed value and the oil pressure for the primary circuit and outputs a directive value. which corresponds to the set pump displacement of the control valve 32 for the vehicle speed. Fig. 9 shows an example of data on engine speed I pilot pressure characteristics. The solid line L21 and the dashed lines L22, L23 in the diagram are lines representing data on engine speed-pilot pressure characteristics which change according to the oil pressure of the primary circuit.
    The vehicle speed control valve 32 varies the angle of inclination of the transport hydraulic pump 9 by controlling the control cylinder 23 for pump displacement in the light of the directive value entered from the control unit 16. The displacement of the transport hydraulic pump 9 is thus controlled to correspond to the engine speed. 533 997 21 The control unit 16 also processes output signals from the engine speed detector 19 and the primary pressure oil pressure detector 22 and outputs a directive directive for the engine displacement to the engine control valve 30. Referring to the engine speed oil pressure characteristics of the primary circuit 16 stored in the control unit the controller issues a tilt command variation command to the engine control valve 30 to increase the engine displacement from the actual value of the engine speed and the oil pressure value of the primary circuit SSH. In this construction vehicle, limitation control of the drive wheel force and suppressive control of a rapid change of the pump displacement can be implemented, similar to the construction vehicle according to the first embodiment. Limitation control of the drive wheel force is a control similar to that of the construction vehicle in accordance with the first embodiment and is therefore not described. Suppressive control of a rapid change in pump displacement is described below.
    [Suppressive control of a rapid change of pump displacement] The control unit 16 can implement a suppressive control of a rapid change of the pump displacement in the light of the output from the second selector 36. Suppressive control of a rapid change of the pump displacement in this construction vehicle is mostly similar that of the construction vehicle according to the first embodiment by controlling the displacement of the transport hydraulic pump 9 so that the displacement of the transport hydraulic pump 9 is gradually changed in accordance with changes in the oil pressure of the primary circuit while the oil pressure of the primary circuit is limited so as not to exceed the limiting pressure value Plt. However, suppressive control of a rapid change of the pump displacement in this construction vehicle differs from the construction vehicle in accordance with the first embodiment in that the pump displacement is controlled by controlling the control valve 32 for vehicle speed. The pilot pressure provided by the control cylinder 23 for the pump displacement is determined on the basis of the oil pressure of the primary circuit and the engine speed. For example, at the oil pressure Pma of the primary circuit, data on engine speed pilot pressure characteristics shown by line L21 in Fig. 9 are used. At the oil pressure Pmb in the primary circuit, engine speed pilot pressure data shown by line L22 in Fig. 9 are used. 9, and at the oil pressure Pmc of the primary circuit, data on engine speed pilot pressure characteristics, shown by line L23 in Fig. 9, are used. The ratio of these pressures is Pma> Pmb> Pmc. Data on engine speed-pilot pressure characteristics L21 to L23, when the engine speed is equal to or greater than a predetermined value Nc, the pilot pressure is set to increase when the oil pressure of the primary circuit decreases if the engine speed remains the same. For example the rotational speed N1 (> Nc) , the pilot pressure is Ppa at the oil pressure Pma of the primary circuit. The transport hydraulic pump 9 is thus driven with the oil pressure of the primary circuit and the pump displacement corresponding to the pump Pa in Fig. 10. With the same engine speed N1, the pilot pressure is Ppb at the oil pressure Pmb of the primary circuit. The transport hydraulic pump 9 is thereby driven by the oil pressure of the primary circuit and the pump displacement corresponding to the pump Pb. With the same engine speed N1, the pilot pressure is Ppc at the oil pressure Pmc of the primary circuit. The transport hydraulic pump 9 is thereby driven by the oil pressure of the primary circuit and the pump displacement corresponding to the point Pc. The pressures have the ratio Ppa <Ppb <Ppc. PQ characteristics, such as those shown in Fig. 10, thus occur. During suppression control of a rapid change of the pump displacement, the control of the pilot pressure causes the PQ characteristic to occur which are similar data of the PQ characteristic L11 'to L15' when suppressing control of a rapid change of the pump displacement according to the first embodiment, shown in Figs. 10. Characteristics of vehicle speed-drive wheel force, similar to those for suppressive control of a rapid change of the pump displacement according to the first embodiment (see Fig. 6) are also shown thereby.
    With this construction vehicle, the same effects can be exhibited as those of the construction vehicle according to the first embodiment, as described above. In the present embodiment, under suppressive control of a rapid change of the pump displacement, the pilot pressure provided to the control cylinder 23 for pump displacement is controlled according to the strength of the oil pressure of the primary circuit, but the pilot pressure can also be controlled according to the vehicle speed instead of the oil pressure of the primary circuit. In this case, data on the engine speed pilot pressure characteristics L21 to L23, shown in Fig. 9, is set so that an engine speed equal to or greater than a predetermined value Nc, the pilot pressure decreasing as the vehicle speed decreases if the engine speed remains the same. ma.
    (Other embodiments) (Å) In the embodiment described above, the present invention is applied to a wheel loader, but the present invention is not limited to a wheel loader and can be applied to any construction vehicle traveling by means of a hydraulic motor and having an HST input. installed.
    (B) In the above embodiment, suppressive control of a rapid change of the pump displacement is performed when selected by the second selector 36, but suppressive control of a rapid change of the pump displacement can also be performed automatically without being selected by a driver. The closest linear characteristic for vehicle speed-drive wheel power is thereby obtained during low-speed operation, and the driver can thus maneuver the accelerator pedal more easily.
    (C) In the first embodiment, described above, suppressive control of a rapid change of the pump displacement is performed by electrically controlling the control valve 24 for the pump displacement, but other control means can be used if the displacement of the transport hydraulic pump 9 is controlled to obtain the oil pressure characteristic of the primary circuit pump displacement shown in Fig. 7. 533 997 24 (D) In the second embodiment described above, the pilot pressure provided to the pump displacement control cylinder 23 is controlled by controlling the vehicle speed control valve 32 according to a control signal from the control unit 16. The upper limit of the pilot pressure corresponding to the engine speed, which is controlled by the vehicle speed control valve 32, can also be controlled by controlling a decompression valve 28 according to a control signal from the control unit 16, shown in Fig. 11. The decompression valve 28 is a electromagnetic, proportional pressure control valve for connecting the directional valve 24 and a pilot circuit 33 through which pressure oil discharged from the charge pump 10 passes, and the decompression valve 28 can control, the pilot pressure provided to the control cylinder 23 for the pump displacement according to a control signal from the control unit 16.
    The position at which the decompression valve 28 is provided is also not limited by the aforementioned position. For example, the decompression valve 28 may be provided divergently from the pilot circuit 33 shown in Fig. 12. The decompression valve 28 may also be provided divergently from the restriction circuit 39 connected to the pilot circuit 33 shown in Fig. 13. Furthermore, the decompression valve is not limited to a only. Two decompression valves may be provided, one being a forward transport decompression valve to provide pilot pressure for forward transport to the pump displacement control cylinder 23 and the other being a rear transport decompression valve to provide a rear transport pilot to the pump displacement control cylinder 23 and the pilot pressure. provided in the pump displacement control cylinder 23 can be controlled in both decompression valves. In this case, the directional valve 24 is absent. In hydraulic circuits such as these, the pilot pressure provided to the pump displacement control cylinder 23 can be controlled to obtain oil pressure characteristics of primary circuit displacement pumps. shown in Fig. 10.
    (E) In the first embodiment, described above, the pump displacement is controlled based on the oil pressure of the primary circuit and the engine speed, but the vehicle speed can also be used as a factor instead of the oil pressure of the primary circuit. 533 997 25 INDUSTRIAL APPLICABILITY The present invention makes it possible to suppress tire slip and sudden accelerations, and the present invention is useful as a construction vehicle.
    权利要求:
    Claims (8)
    [1]
    Construction vehicle (1) comprising: an engine (8); a transport hydraulic pump (9) driven by the motor (8); a transport hydraulic circuit (20, 21) through which pressure oil discharged from the transport hydraulic pump (9) flows; a transport hydraulic motor (12) driven by the pressure oil provided by the transport hydraulic circuit (20, 21); a transport wheel (4a, 4b) driven by the driving force of the transport hydraulic motor (12); a hydraulic pump (11) for work equipment (3), which is driven by the motor (8); a working equipment (3), driven by pressure oil, discharged from the hydraulic pump (11) of the working equipment (3); a control unit (16) for controlling engine speed, the displacement of the transport hydraulic pump (9), and the displacement of the transport hydraulic motor (12) for controlling vehicle speed and drive wheel force; and an oil pressure limiting component (31) for limiting the transport circuit pressure so as not to exceed a predetermined limit pressure value (Plt), the transport circuit pressure being the pressure of pressure oil flowing through the transport hydraulic circuit (20, 21); wherein the control unit (16) can implement a suppressive control of rapid change of the pump displacement to control the displacement of the transport hydraulic pump (9), so that the transport circuit pressure reaches a maximum value equal to or less than the limit pressure value (Plt) when the vehicle (1) has stopped at engine speed equal with or greater than the engine speed at which the oil pressure limiting component (31) limits the transport circuit pressure so that the transport circuit pressure reaches the limit pressure value (Plt) and the transport circuit pressure does not change even if the displacement of the transport hydraulic pump (9) changes when the rapid change suppression control is not selected. and the displacement of the transport hydraulic pump (9) gradually increases as the transport circuit pressure decreases from a maximum value; wherein said suppressive control of rapid change of the pump displacement results in the pump displacement gradually changing so that wheel slip and sudden acceleration can be suppressed. 533 997 27
    [2]
    Construction vehicle (1) comprising: an engine (8); a transport hydraulic pump (9) driven by the motor (8); a transport hydraulic circuit (20, 21) through which pressure oil discharged from the transport hydraulic pump (9) flows; a transport hydraulic motor (12) driven by the pressure oil provided by the transport hydraulic circuit (20, 21); a transport wheel (4a, 4b) driven by the driving force of the transport hydraulic motor (12); a hydraulic pump (11) for work equipment (3), which is driven by the motor (8); a working equipment (3), driven by pressure oil, discharged from the hydraulic pump (11) of the working equipment (3); a control unit (16) for controlling engine speed, the displacement of the transport hydraulic pump (9), and the displacement of the transport hydraulic motor (12) for controlling vehicle speed and drive wheel force; and an oil pressure limiting component (31) for limiting the transport circuit pressure so as not to exceed a predetermined limit pressure value (Plt), the transport circuit pressure being the pressure of pressure oil flowing through the transport hydraulic circuit (20, 21); wherein the control unit (16) can implement a suppressive control of rapid change of the pump displacement to control the displacement of the transport hydraulic pump (9), so that the displacement of the transport hydraulic pump (9) gradually decreases as the transport circuit pressure increases, and the transport circuit pressure reaches a maximum value equal to or less than the limit pressure value (Plt) when the vehicle (1) has stopped at the engine speed equal to or greater than the engine speed at which the oil pressure limiting component (31) limits the transport circuit pressure so that the transport circuit pressure reaches the limit pressure value (Plt) and the transport circuit pressure 9 does not change displacement changes when the oppressive control of rapid change has not been chosen; wherein said suppressive control of rapid change of the pump displacement results in the pump displacement gradually changing so that wheel slip and sudden acceleration can be suppressed.
    [3]
    Construction vehicle (1) according to claim 1 or 2, further comprising: a transport circuit pressure detector (22) for detecting the transport circuit pressure; and an engine speed detector (19) for detecting the engine speed; wherein the control unit (16) controls the displacement of the transport hydraulic pump (9) under the suppressive control of rapid change of the pump displacement against the background of the transport circuit pressure detected by the pressure detector (22) of the transport circuit and the engine speed detected by the engine speed detector (19). .
    [4]
    A construction vehicle (1) according to claim 1 or 2, further comprising: a vehicle speed detector (34) for detecting the vehicle speed; and an engine speed detector (19) for detecting the engine speed; wherein the control unit (16) controls the displacement of the transport hydraulic pump (9) against the background of the vehicle speed, which is detected by the vehicle speed detector (34) and the engine speed is detected by the engine speed detector (19) during the suppressive control of rapid change of pump displacement.
    [5]
    Construction vehicle (1) according to claim 1 or 2, comprising: an electromagnetic, proportional control valve (24), which can control the displacement of the transport hydraulic pump (9) required; wherein the control unit (16) controls the displacement of the transport hydraulic pump (9) by electrically controlling the electromagnetically proportional control valve (24).
    [6]
    Construction vehicle (1) according to claim 1 or 2, further comprising: a control mechanism (23) for the pump displacement for varying the pump displacement of the transport hydraulic pump (9) in accordance with the provided pilot pressure; and a pressure control valve (28) capable of controlling the pilot pressure provided to the pump displacement control mechanism (23); wherein the control unit (16) controls the pump displacement of the transport hydraulic pump (9) by electrically controlling the pressure control valve.
    [7]
    Construction vehicle (1) according to claim 1 or 2, wherein: the control unit (16) controls the displacement of the transport hydraulic pump (9) under the suppressive control of rapid change of the pump displacement, so that a maximum drive wheel force in the characteristic of vehicle speed-drive wheel force arises at a lower speed than the maximum drive wheel force in the characteristic of vehicle speed drive wheel force in cases where the suppressive control of rapid change of the pump displacement is not implemented. 533 997 29
    [8]
    Construction vehicle (1) according to claim 1 or 2, further comprising: a selector (36) for allowing a driver to select implementation of the suppressive control of rapid change of pump displacement.
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    同族专利:
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JPH0314966A|1989-06-09|1991-01-23|Komatsu Ltd|Controller of variable capacity motor for hydraulic driven vehicle|
    EP0484526B1|1989-06-09|1995-11-15|Kabushiki Kaisha Komatsu Seisakusho|Device for controlling variable capacity motor of hydraulic drive vehicle|
    DE3935068C2|1989-10-20|1993-01-14|Sauer-Sundstrand Gmbh & Co, 2350 Neumuenster, De|
    JP2818474B2|1990-07-04|1998-10-30|日立建機株式会社|Hydraulic drive circuit|
    WO1994004828A1|1992-08-25|1994-03-03|Hitachi Construction Machinery Co., Ltd.|Hydraulic drive unit of hydraulic working machine|
    JPH08135789A|1994-11-09|1996-05-31|Komatsu Ltd|Transmission for vehicular hydraulic drive device and control method for the transmission|
    US5561979A|1995-02-17|1996-10-08|Caterpillar Inc.|Control arrangement for a hydrostatic system|
    CA2213457C|1995-03-14|2005-05-24|The Boeing Company|Aircraft hydraulic pump control system|
    JP3014966B2|1996-05-17|2000-02-28|博 滝本|Golf swing practice equipment|
    JP4136041B2|1997-12-04|2008-08-20|日立建機株式会社|Hydraulic drive device for hydraulic working machine|
    JP2001146963A|1999-09-08|2001-05-29|Komatsu Ltd|Transmission device with hydraulic motor|
    JP3812728B2|2001-12-13|2006-08-23|株式会社小松製作所|Upper revolving work vehicle|
    JP4208179B2|2002-10-28|2009-01-14|株式会社小松製作所|Hydraulic drive vehicle|
    JP4188902B2|2004-11-22|2008-12-03|日立建機株式会社|Control equipment for hydraulic construction machinery|
    US7415822B1|2005-07-21|2008-08-26|Deere & Company|Load sense boost device|
    JP4989951B2|2006-10-25|2012-08-01|株式会社小松製作所|Construction vehicle|
    US7549287B2|2007-09-14|2009-06-23|Cnh America Llc|Hydrostatic auto/manual speed control|
    KR100974279B1|2008-03-27|2010-08-06|볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비|travel system for heavy equipment|JP4989951B2|2006-10-25|2012-08-01|株式会社小松製作所|Construction vehicle|
    JP5064160B2|2007-09-19|2012-10-31|株式会社小松製作所|Engine control device|
    WO2010074494A2|2008-12-24|2010-07-01|두산인프라코어 주식회사|Emergency engine rpm control apparatus for heavy construction equipment|
    JP5072926B2|2009-09-03|2012-11-14|株式会社小松製作所|Work vehicle|
    EP2466017A1|2010-12-14|2012-06-20|Caterpillar, Inc.|Closed loop drive circuit with open circuit pump assist for high speed travel|
    EP2673422B1|2011-02-07|2015-03-25|Caterpillar, Inc.|Hydrostatic system configured to be integrated in an excavator|
    DE102011113485A1|2011-09-15|2013-03-21|Bomag Gmbh|Method for driving a drive train of a vehicle and device for carrying out the method|
    JP5106694B1|2012-03-15|2012-12-26|株式会社小松製作所|Work vehicle and control method of work vehicle|
    US8666610B2|2012-03-15|2014-03-04|Komatsu Ltd.|Work vehicle and method for controlling work vehicle|
    JP5113946B1|2012-03-27|2013-01-09|株式会社小松製作所|Work vehicle and control method of work vehicle|
    US8701818B2|2012-03-29|2014-04-22|Komatsu Ltd.|Work vehicle and control method for work vehicle|
    JP5092059B1|2012-03-29|2012-12-05|株式会社小松製作所|Work vehicle and control method of work vehicle|
    WO2013145342A1|2012-03-30|2013-10-03|株式会社小松製作所|Wheel rotor and method for controlling wheel rotor|
    JP5092061B1|2012-03-30|2012-12-05|株式会社小松製作所|Work vehicle and control method of work vehicle|
    JP5092060B1|2012-03-30|2012-12-05|株式会社小松製作所|Work vehicle and control method of work vehicle|
    EP2667059B1|2012-03-30|2016-06-01|Komatsu, Ltd.|Wheel loader and method for controlling wheel loader|
    US20140069092A1|2012-09-07|2014-03-13|Caterpillar, Inc.|Traction Control System for a Hydrostatic Drive|
    US9772018B2|2013-03-27|2017-09-26|Kubota Corporation|Working machine|
    DE102016205891A1|2016-04-08|2017-10-12|Robert Bosch Gmbh|Hydrostatic drive and vehicle with such a hydrostatic drive|
    WO2019003762A1|2017-06-27|2019-01-03|株式会社小松製作所|Work vehicle and method for controlling work vehicle|
    WO2019003761A1|2017-06-27|2019-01-03|株式会社小松製作所|Work vehicle and method for controlling work vehicle|
    WO2019003763A1|2017-06-27|2019-01-03|株式会社小松製作所|Work vehicle and method for controlling work vehicle|
    JP6749351B2|2018-01-19|2020-09-02|酒井重工業株式会社|Construction vehicle|
    DE102018210685A1|2018-06-29|2020-01-02|Robert Bosch Gmbh|Hydrostatic drive and method for controlling the hydrostatic drive|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    JP2007116722A|JP5074086B2|2007-04-26|2007-04-26|Construction vehicle|
    PCT/JP2008/052931|WO2008136204A1|2007-04-26|2008-02-21|Construction vehicle|
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