• 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:
    In a hydrostatic drive system for a mobile work machine, in particular an industrial truck, with at least one pump (2) for a pressure medium, which via a supply line feeds a working hydraulics (3) with at least one consumer with pressure medium, is through the bypass valve (24) the supply line ( 9) connectable to a heat exchanger (26) for cooling the pressure medium.Fig. 1
    公开号:SE1351372A1
    申请号:SE1351372
    申请日:2013-11-20
    公开日:2014-05-23
    发明作者:Markus Schwab
    申请人:Still Gmbh；
    IPC主号:
    专利说明:

    to provide the desired consumer movement is required, for example in lifting operation of a lifting drive of the working hydraulics, thus flows over the think wave excess volume flow, which corresponds to the difference between the feed flow delivered by the pump and the useful volume required by the controlled consumer.
    A disadvantage of this known technique is that the pressure medium flow through the heat exchanger device in the return line, which determines the cooling effect and thus the cooling of the pressure medium, shows sharp oscillations and the cooling cannot be controlled expediently. For this reason, it can lead to an overheating of the pressure medium.
    Furthermore, it is already known to arrange a heat exchanger device in a return line led to a tank for the working hydraulics of a work machine. For this reason, however, in the return line, for example in lowering operation of a lifting drive of the working hydraulics, high flow losses at the heat exchanger device can occur and thus undesired effects of the lowering speed through this additional stop pressure occur. Especially when lowering an unloaded load handler, the working speed of an industrial truck can thereby be affected.
    Furthermore, it is known to arrange a separate cooling circuit in parallel with the working hydraulics or other hydraulic circuits as additional pump circuits. A disadvantage of this prior art, however, is the extra cost of an additional pump.
    From DE 10 2010 024 551 A1 a hydrostatic drive system is known, in which a heat exchanger device for cooling the pressure medium is arranged in a return line of a circuit pressure wave of a working hydraulics.
    It is also known to arrange two pumps in a hydrostatic drive system. For example, DE 103 15 494 A1 discloses a hydrostatic drive system for a battery-electrically driven industrial truck, in which a first pump for supplying the working hydraulics is arranged and a second pump serves for supplying a hydraulic control. The object of the invention is to provide a hydrostatic drive system, in which an overheating of the hydraulic fluid or the pressure medium can be avoided at a low cost and in addition only insignificant power losses occur when flowing through the heat exchanger device.
    This object is solved by a hydrostatic drive system with the features according to claim 1.
    Advantageous embodiments of the invention are provided by the subclaims. The object is solved according to the invention by a hydrostatic drive system for a mobile work machine, in particular an industrial truck, with at least one pump for a pressure medium, which via a supply line feeds a working hydraulics comprising at least one consumer comprising with a pressure medium, through a bypass valve the supply line can be connected to a heat exchanger for cooling the pressure medium.
    It is thus advantageously avoided that in a neutral circuit the pressure medium must be led via a control valve device of the working hydraulics, such as for instance a circuit pressure wave in order to be able to cool the pressure medium. Furthermore, it does not lead to any effect of the lowering speed in the case of a lifting device such as working hydraulics due to an additional stop pressure through the flow of pressure medium via the heat exchanger device. On the whole, there is no effect on the functions of the working hydraulics, as as far as possible the outflow of pressure medium from the working hydraulics with low resistance is sought. Via the bypass valve, a constant volume flow for cooling the pressure medium or the hydraulic fluid can advantageously be set.
    In particular, a hydrostatic drive system for all manoeuvrable functions of a mobile work machine with a single pump can thereby be realized. This is particularly advantageous in the case of electrically driven industrial trucks, such as with a drive battery and electric motors such as propulsion motors driven forklifts, which then only need a single pump driven by an electric motor for the hydraulic fluid. The hydrostatic drive system according to the invention is also advantageous to use in internal combustion engine electrically driven industrial truck systems, in which an internal combustion engine drives a generator which drives electric drive motors via a direct voltage intermediate circuit and converter. In these, the pump of the hydrostatic drive system, either arranged separately at the internal combustion engine or by its own electric motor, can be driven and feed all the hydrostatically driven functions of the industrial truck with pressure medium. Advantageously, the bypass valve is arranged in a branch line to the supply line.
    Thereby, for example, for the function of the bypass valve, a cost-effective available, controllable proportional valve can be used, which steplessly controllably can open the branch line, from completely closed to completely open. Thereby, a control adapted to the operating conditions and the temperature of the hydraulic fluid or pressure medium is possible, to the extent that a total volume flow through the pump is provided or the pump is also controlled accordingly and its feed rate can be increased at higher temperatures. Advantageously, due to the arrangement of the bypass valve in the branch line, no additional flow resistance arises in the supply line during the supply of the working hydraulics. In an alternative embodiment, however, it is also conceivable for the bypass valve to be arranged as a 2/3-way valve in the supply line, through which a partial flow of the pressure medium via the third connection is led to the heat exchanger device.
    In an advantageous embodiment of the invention, upstream of the bypass valve in the supply line, a priority valve for supplying at least one priority consumer is arranged, in particular a hydraulic control and / or a brake.
    When the priority valve is arranged between the pump and the bypass valve, it can not in any operating position, especially even in the case of high cooling demand of the hydraulic fluid or the pressure medium, lead to an effect of the pressure medium supply to the priority consumer needing feed, especially a hydraulic control and / or a brake.
    The priority valve can be operated by means of a spring in the direction of a position in the pump supply line with the priority consumer, in particular the hydraulic control and / or the brake connecting. Advantageously, a control valve device for controlling the working hydraulics has a circuit pressure wave which is operated by the highest load pressure of the consumers of the working hydraulics and a spring in the direction of a shut-off position and the supply pressure of the pump in a flow-through position.
    In an advantageous embodiment, the pump may be a constant type pump.
    The drive system according to the invention can by this design be designed as a so-called Open-Center-System, in which the pump can be designed as a constant type pump and the control valve device for controlling the working hydraulics has a circuit pressure wave, which is operated by the highest load pressure of the working hydraulics consumers. and a spring in the direction of the sum of the forces of a locking position and the supply pressure of the pump in a flow-through position direction. In such a drive system, the system pressure upstream of the priority valve, especially in the case of unmaneuvered consumers, is also determined by the spring bias of the circuit pressure wave, whereby at the bypass valve, especially in the case of unmaneuvered consumers, a correspondingly higher pressure occurs. cooling of the hydraulic fluid or pressure medium.
    In an advantageous embodiment, an additional pump supplies the working hydraulics with pressure medium via an additional supply line.
    When an additional pump is provided, it is possible to use the first pump with the supply line only when a high power requirement is needed and / or in case of cooling demand of the pressure medium. A second pump, in the present embodiment the hydraulic pump referred to as an additional pump, can mainly provide the pressure means of the working hydraulics and the first pump is only switched on in cases where a particularly high power demand arises during the working hydraulics and / or the temperature of the hydraulic fluid or pressure medium is too high. In particular, this makes it possible to control the pressure medium flow over the heat exchanger device energy-efficiently over the feed volume flow of the pump, since independently of this the additional pump feeds the working hydraulics with pressure medium. According to a preferred embodiment, upstream of the bypass valve in the further supply line, a priority valve for the supply of at least one priority consumer is arranged, in particular a hydraulic control and / or brake.
    Since the additional pump provides the main supply with pressure medium, it is advantageous to arrange in this the priority valve for the priority consumers.
    According to a preferred embodiment of the invention, a first shut-off valve, in particular a non-return valve, is arranged in the further supply line upstream of the working hydraulics, opening first shut-off valve in the direction of the working hydraulics.
    Thereby, the supply of the working hydraulics with pressure medium can be ensured even in the event of a failure of the additional pump.
    A second shut-off valve, in particular a non-return valve, can be arranged in the supply line upstream of the working hydraulics and downstream of the connection of the branch line.
    Furthermore, in the event that a pump falls off, or the first pump and / or bypass valve, for example when it is stuck in the open position, all functions of the working hydraulics are further possible as well as a control in the case of a hydraulic control, where the additional pump can still provide sufficient pressure for the working hydraulics and is separated by the non-return valve from the bypass valve.
    Advantageously, the first shut-off valve and the second shut-off valve are each arranged upstream of a connection point of the supply line and the further supply line. In order to supply the coolant requirements of the drive system, a temperature sensor which senses the temperature of the pressure medium can be provided.
    The bypass valve can be designed as a control valve, in particular as an electromagnetically operable control valve, which can be controlled depending on the signal of the temperature sensor.
    Advantageously, the bypass valve is designed as a controllable proportional valve, in particular an electromagnetically controllable proportional valve, which can be controlled depending on the signal of the temperature sensor.
    This enables a control depending on the temperature of the hydraulic fluid or pressure medium by controlling a vehicle control depending on the temperature sensor of the bypass valve. Alternatively, a control through a pulsed control of a simple valve is also conceivable, which is not a proportional valve.
    The pressure medium can drain downstream of the heat exchanger in a tank.
    Further advantages and features of the invention are further illustrated in the embodiments shown in connection with the schematic figures, where Fig. 1 shows a first embodiment of a hydrostatic drive system according to the invention and Fig. 2 shows a second embodiment of a hydrostatic drive system according to the invention.
    Fig. 1 shows a hydrostatic drive system according to the invention, designed as an Open-Center system, in, for example, a mobile work machine designed as an industrial truck in a schematic wiring diagram.
    The hydrostatic drive system comprises a pump 2 designed as a constant pump 1, which is driven in an open circuit and is arranged for feeding a working hydraulics 3 and for example a hydraulic control 4 as priority consumer 5. The pump 2 sucks out a tank 6 via a filter 7 as well as a suction line 8 and a supply line 9, in which a priority valve 10 is arranged for suitable feeding of the priority consumer 5. From the priority valve 10, a supply branch line 11 leads to the priority consumer 5.
    The priority valve 10 can be operated by means of a spring 12 and the load pressure of the priority consumer 5 in a load pressure sensor line 13 of the priority consumer 5 in the direction of the supply line 9 with the supply branch line 11 for suitable supply of the priority consumer 5 connecting position 14. By means of the supply pressure generated in the supply branch line 11, the priority valve 10 can be operated in the direction of a position 16, in which the supply line 9 is connected to the supply branch line and a further part of the supply line 9 for simultaneous supply of the priority consumer 5 and working hydraulics 3.
    The working hydraulics 3 may in the embodiment of the working machine as an industrial truck comprise, for example, a lifting drive, a tilting drive, a side sliding device and one or more auxiliary consumers. The supply line 9 leads to a control valve block 17 as part of a control valve device 18 of the working hydraulics 3. The control valve block 17 comprises, for controlling each consumer of the working hydraulics 3, a control valve designed as a road valve. In the control valve device 18 a circuit pressure wave 19 is arranged, which is arranged in a branch line 20 running from the supply line 9 to the tank 6. A tank line 15 enables the return of the pressure medium in the tank 6 from the consumers or the control valve block 17. The circuit pressure wave 19 is operated by a load pressure sensor branch line 21 standing, the highest load pressure of the consumers of the working hydraulics 3 and a spring 22 in the direction of a locking position and of the supply pressure arising in the supply line 9 in the direction of a flow-through position.
    According to the invention, a supply line 23 runs in the branch line 9 between the priority valve 10 and the control valve block 17 of the working hydraulics 3, in which the bypass valve 24 is arranged. Through the bypass valve 24, the flow of pressure medium or hydraulic fluid can be controlled by a heat exchanger device 25 with a heat exchanger 26. The heat exchanger 26 delivers the heat of the pressure medium or hydraulic fluid to the environment and flows through air by means of an aerator the pressure medium via a filter 29 into the tank 6. 10 15 20 25 30 35 In an industrial truck driven by an internal combustion engine, the pump 2 can be driven by the internal combustion engine, or even by its own electric motor, as is usually the case with a battery-electrically powered industrial truck. When an elevated temperature of the pressure medium in the tank 6 or at another measuring point suitable for this purpose is determined by a temperature sensor (not shown), a control, for example the vehicle control of the mobile work machine, via the bypass valve 24 at a corresponding speed of the pump 2 can lead a volume of the pressure medium through the heat exchanger device 25 directly back into the tank 6. Thereby the pressure medium is cooled. Suitably no further flow resistance arises when, for example, pressure medium via the tank line 15 of the working hydraulics 3 flows from the consumers back into the tank 6 and it does not lead to an undesired effect on the function of the consumer of the working hydraulics 3. Especially in the case when a consumer a lifting device is provided. a reduction in the lowering speed. The solution according to the invention for cooling the hydraulic fluid can be made with a single pump and in itself causes a little loss effect.
    Fig. 2 shows a second embodiment of the hydrostatic drive system according to the invention.
    The components of the components corresponding to Fig. 1 are denoted by the same reference numerals. The drive system comprises a pump 2 designed as a constant pump 1, which here is arranged driven as a first pump as well as in an open circuit and for feeding the working hydraulics 3 at high power requirements. The pump 2 sucks out of the tank 6 via the filter 7 as well as the suction line 8 and feeds into the supply line 9. A further, second pump 30 also sucks via suction line 8 and the filter 7 pressure medium from the tank and leads this in a further supply line 31 in which for suitable supply of the present 5, in the present example the hydraulic control 4 a priority valve 32 is provided. From the priority valve 32, the supply manifold 11 leads to the priority consumer 5. The priority valve 32 is operable by means of a spring 33 and the load pressure of the priority consumer 5 standing in the load pressure sensor manifold 13 of the priority consumer 5 in the direction of a further supply line 31 with the supply manifold 11 for suitable supply of the present consumer 5 connecting position 14. Due to the supply pressure generated in the supply branch line 11, the priority valve 10 is operable in the direction 16 of the position 16, in which the further supply line 31 is connected to the supply branch line 11 and a second part of the further supply line 31 for simultaneous supply of the priority consumer 5 and the working hydraulics 3. The additional pump 30 in this case continuously feeds pressure medium and supplies the working hydraulics 3 alone with hydraulic fluid or pressure medium, when there is only a small power requirement. The working hydraulics 3 may in the embodiment of the working machine as an industrial truck also in this embodiment according to the invention comprise a lifting drive, a tilting drive, a side sliding device and one or more auxiliary consumers. The second part of the further consumer 31 is connected via a first shut-off valve 34, for example a non-return valve 35, which opens in the direction of the working hydraulics 3, in a connection point 36 with the supply line 9, in which a second shut-off valve 37, for example a non-return valve 38 is arranged. opens in the direction of working hydraulics 3. From the connection point 36 a common supply line 39 leads to the control valve block 17 as part of the control valve device 18 of the working hydraulics 3. The control valve block 3 comprises for controlling each consumer of the working hydraulics 3 a control valve designed as a road valve and over the tank line 15 the return flow In the control valve device 18, the circuit pressure wave 19 is arranged, which is arranged in the branch line 20 going from the common supply line 39 to the tank. The circuit pressure wave 19 is by the sum of the forces of the highest load pressure of the consumer of the working hydraulics 3 22 in the direction of a blocking position and of the supply pressure arising in the common supply line 39 in a flow-through position.
    From the supply line 9, the branch line 23 runs upstream of the shut-off valve 37, in which the bypass valve 24 is arranged. Through the bypass valve 24, the flow of pressure medium or hydraulic fluid can be controlled through the heat exchanger 26. The heat exchanger delivers the heat of the pressure medium or hydraulic fluid to the environment and is flowed by air by means of the aerator 27.
    The outlet line 28 is connected to the branch line 20 of the circuit pressure wave 19 and directs the pressure medium via the filter 29 into the tank 6.
    When an increased temperature of the pressure medium in the tank 6 or at another suitable measuring point is determined by the temperature sensor (not shown), the control, for example the vehicle control of the mobile machine, via the bypass valve 24 and the corresponding speed of the pump 2 can directly return a volume of pressure medium through the heat exchanger device 25 in the tank 6.
    This cools the pressure medium. Conveniently, the pump 2 only needs to be run when either the pressure medium needs to be cooled and / or there is an increased power requirement in the working hydraulics 3.
    The volume flow for cooling the pressure medium is then completely independent of the priority consumer 5 to be fed, for example the hydraulic control 4. When the pump 2 only needs to be switched on or run for cooling when the pressure medium temperature has exceeded a threshold value, only a small loss effect occurs. As stated in the previous embodiment, no further flow resistance arises, when for example pressure medium flows over the tank line 15 of the working hydraulics 3 from the consumers back into the tank 6 and it does not lead to undesired influence on the mode of operation of the working hydraulics 3 consumers. In particular, in the case where a lifting device is arranged as a consumer, a reduction of the lowering speed is avoided.
    In case the bypass valve 24 falls off, for example when this jam is in the open position, all functions of the working hydraulics 3 are again available and a control of the hydraulic control 4 is further possible, as an additional pump 30 can still set a sufficient pressure for the working hydraulics 3. available and through the second shut-off valve 37 is separated from the bypass valve 24 and the manifold 23. 11
    权利要求:
    Claims (15)
    [1]
    1. 0 15 20 25 30
    [2]
    2. Claims
    [3]
    Hydrostatic drive system for a mobile work machine, in particular an industrial truck, with at least one pump (2) for a pressure medium, which feeds via a supply line (9) working hydraulics (3) comprising at least one consumer with the pressure medium, characterized in that bypass valve (24), the supply line (9) can be connected to a heat exchanger (26) for cooling the pressure medium.
    [4]
    Hydrostatic drive system according to Claim 1, characterized in that the bypass valve (24) is arranged in a branch line (23) of the supply line (9).
    [5]
    Hydrostatic drive system according to Claim 1 or 2, characterized in that, upstream of the bypass valve (24) in the supply line (9), a priority valve (10) for supplying at least one priority consumer (5) is provided, in particular a hydraulic control (4) and / or a brake.
    [6]
    Hydrostatic drive system according to Claim 3, characterized in that the priority valve (10) is actuated by means of a spring (12) in the direction of a supply line (9) in the pump (2) with the priority consumer (5), in particular the hydraulic control ( 4) and / or brake, connecting position (14).
    [7]
    Hydrostatic drive system according to one of Claims 1 to 4, characterized in that a control valve device (18) for controlling the working hydraulics (3) has a circuit pressure wave (19), which has one of the highest load pressures of the working hydraulics (3) and a spring ( 22) in the direction of a shut-off position and the supply pressure of the pump (2) is operated in a flow-through position.
    [8]
    Hydrostatic drive system according to one of Claims 1 to 5, characterized in that the pump (2) is a constant pump (1).
    [9]
    Hydrostatic drive system according to one of Claims 1 to 6, characterized in that an additional pump (30) feeds the working hydraulics 12 via a further supply line (31).
    [10]
    10.
    [11]
    11.
    [12]
    12.
    [13]
    13.
    [14]
    14.
    [15]
    15. (3) with pressure medium. Hydrostatic drive system according to claim 7, characterized in that, upstream of the bypass valve (24) in the further supply line (31) is a priority valve (32) for supplying at least one priority consumer (5), in particular a hydraulic control (4) and / or brake . Hydrostatic drive system according to Claim 7 or 8, characterized in that, in the further supply line (31) upstream of the working hydraulics (3), a first shut-off valve (34) opening in the direction of the working hydraulics (3), in particular a non-return valve (35), is provided. Hydrostatic drive system according to one of Claims 1 to 9, characterized in that, in the supply line (9) upstream of the working hydraulics (3) and downstream of the branch line (23), there is a second shut-off valve (37) opening in the direction of the working hydraulics (3), in particular a non-return valve ( 38) arranged. Hydrostatic drive system according to claims 9 and 10, characterized in that, the first shut-off valve (34) and the second shut-off valve (37) are each arranged upstream of a connection point (36) of the supply line (9) and the further supply line (31). Hydrostatic drive system according to one of Claims 1 to 11, characterized in that, in order to sense the cooling power requirement of the drive system, a temperature sensor which senses the temperature of the pressure medium is provided. Hydrostatic drive system according to one of Claims 1 to 12, characterized in that the bypass valve (24) is a control valve, in particular an electromagnetically operable control valve, which can be controlled depending on the signal of the temperature sensor. Hydrostatic drive system according to one of Claims 1 to 12, characterized in that the bypass valve (24) is a controllable proportional valve, in particular an electromagnetically operable proportional valve, which can be controlled depending on the signal of the temperature sensor. Hydrostatic drive system according to one of Claims 1 to 14, characterized in that, upstream of the heat exchanger (26), the pressure medium flows into a tank (6). 13 14
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    同族专利:
    公开号 | 公开日
    FR2998342B1|2020-09-11|
    FR2998342A1|2014-05-23|
    SE541102C2|2019-04-09|
    DE102012111256A1|2014-05-22|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE10315494A1|2003-04-04|2004-10-21|Linde Ag|Hydraulic system for electrically driven floor conveyor, has pump that is driven by electric motor to cool structural component of floor conveyor and actuate hydraulic steering mechanism and drive axle|
    DE102010024551A1|2010-06-22|2011-12-22|Linde Material Handling Gmbh|Hydrostatic drive system|CN108953301B|2018-09-28|2020-01-10|上海中联重科桩工机械有限公司|Oil supplementing system|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DE201210111256|DE102012111256A1|2012-11-22|2012-11-22|Hydrostatic propulsion system of mobile working machine e.g. industrial truck, has feed pipe that is connected with heat exchanger by bypass valve for refrigeration of pressure medium supplied from pump|
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