• 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:
    A damping device (3) for damping oscillations in a hydraulic system (1) of a working machine, which damping device comprises at least one accumulator (5, 17) for accumulating hydraulic fluid of the hydraulic system, and a valve device (20) connected between said at least one accumulator and the hydraulic system . The valve device has a first flow resistance of the hydraulic fluid during the majority of the time the hydraulic fluid flows through the valve device towards the at least one accumulator, and a second flow resistance of the hydraulic fluid during the majority of the time the hydraulic fluid flows through the valve device towards the at least one accumulator. , which second flow resistance is greater than the first flow resistance.
    公开号:SE1651226A1
    申请号:SE1651226
    申请日:2016-09-12
    公开日:2018-03-13
    发明作者:Nilsson Simon
    申请人:Hultdin System Ab；
    IPC主号:
    专利说明:

    The present invention relates to a damping device for damping oscillations in a hydraulic system of a working machine, e.g. a forestry machine or a construction machine, which damping device comprises at least one accumulator and a valve device connected between said at least one accumulator and the hydraulic system.
    The present invention also relates to a working machine comprising such a damping device and to a method for damping oscillations in a hydraulic system of a working machine with such a damping device.
    In work machines, e.g. in forestry and construction machinery, hydraulics are used to perform many tasks. Hydraulic cylinders hold or lift loads in all shapes. It is most common for hydraulic oil to be used in hydraulic systems, but other types of hydraulic fluid occur and are becoming more common. Hydraulic fluids have in common the property that they are relatively incompressible, which gives hydraulic systems great opportunities for movements with high precision.
    The reluctance of the hydraulic fluid to be compressed unfortunately also means that pressure fluctuations and pressure shocks are effectively propagated in the hydraulic system. Pressure fluctuations or shocks are congenerated by the hydraulic system itself, e.g. through flow changes, or by external asterisks, e.g. as a result of the work machine being driven in uneven terrain. Single-work machine is usually built of metal profiles and thus always has a certain amount of "built-in" suspension by the metal springs, but mechanical shocks and movements from hydraulic components can still cause fl your negative effects, such as e.g. degraded driver environment, degraded efficiency due to the operator having to wait for the work machine and / or its implements to stop turning, and degraded service life of the work machine and / or machine components.
    In the case of pressure fluctuations generated by mechanical loads, the force to which the machine is subjected, and by extension also the driver, is directly dependent on the acceleration of the working machine or the machine part in question.
    Thus, it is common for work machines to be equipped with one or more hydraulic P2122SE TXTO1 1 damping devices, or dampers, to dampen pressure fluctuations and pressure shocks in the hydraulic system and thus minimize the negative effects that these entail.
    A hydraulic damper normally consists of one or more accumulators as well as one or fl your throttle valves, or throttles. The accumulator acts as a spring in the system, ie. it accumulates hydraulic fluid when the pressure in the hydraulic system increases and returns the hydraulic fluid when the hydraulic pressure drops again. The function of the throttle valve is to brake the inlet to and out of the hydraulic fluid from the accumulator so that a suitable attenuation is achieved. By adjusting the accumulator pre-charge pressure and the throttle valve throttle, the test machine designers achieve the desired attenuation. To widen the damping range, the damping device may comprise several accumulators with different pre-charge pressures, the cake working against one and the same throttling valve or against different throttling valves, which may have different degrees of throttling. In hydraulic systems, it is generally desirable to eliminate pressure fluctuations as quickly and as gently as possible.
    One problem, however, is that there is an inherent contradiction between rapid attenuation and gentle attenuation. In order to obtain a rapid attenuation, it is desirable to design the throttle valve with a small flow cross-section, i.e. a small cross-sectional area in the flow direction. But the flow cross-section cannot be made too small, because then you approach more and more the behavior of an unampled system. It is thus necessary to compromise between a "hard" and a "soft" damping and allow a certain "" suspension "" for the hydraulic system to have time to brake in and turn the movement without it resulting in jerks and shocks.
    An object of the present invention is to at least partially remedy this problem and provide a damping device and associated method which provides an improved damping.
    The damping device according to the invention is characterized in that the valve device has a first flow resistance for the hydraulic fluid during the majority of the time when the hydraulic fluid flows through the valve device towards said at least one accumulator, and a second flow resistance for the hydraulic fluid during the majority of the time the hydraulic fluid flows through the valve device. an accumulator, which second flow resistance is greater than the first flow resistance.
    The method according to the invention is characterized by the steps: - that the damping device is caused to have a first flow resistance for the hydraulic fluid during the majority of the time when the hydraulic fluid flows through the valve device towards said at least one accumulator, and - that the damping device is caused to have a second hydraulic fluid. the majority of the time when the hydraulic fluid flows through the valve device in the direction out of said at least one accumulator, which second flow resistance is greater than the first flow resistance.
    The valve device may comprise at least one controllable throttle valve, which comprises a first valve port for connection to the hydraulic system and a second valve port, which is connected to at least one accumulator, which at least one throttle valve comprises a first valve position, which has a first flow cross section, and a second valve position, which has a second flow cross-section, which second flow cross-section is smaller than the first flow cross-section, which at least one throttle valve is arranged to occupy the first valve position during the main part of the time when hydraulic fluid flows through the throttle valve towards said at least one accumulator, and the second hydraulic valve position during flows through the throttle valve in the direction out of said at least one accumulator.
    Said at least one throttle valve can e.g. be arranged to assume the first valve position when PA> PB + Ap bias and the second valve position when PA <PB + Ap bias where PA is the hydraulic pressure at the first valve port, PB is the hydraulic pressure at the second valve port, and APfi equivalent voltage is a pressure difference between the first valve port and the second valve port corresponding to a compressive force with which a predetermined bias of the throttle valve affects the valve body.
    The bias voltage can be arranged to be negligible in comparison with the compressive forces with which the hydraulic fluid flowing through the throttle valve acts on the valve body, the throttle valve being arranged to assume the first valve position when the hydraulic pressure at the first valve port is higher than the second hydraulic port and the second valve pressure. the hydraulic pressure at the second valve port is higher than the hydraulic pressure at the first valve port.
    The area of the second flow cross-section may be in the range of 0.1% to 90% of the area of the first flow cross-section.
    The at least one accumulator may comprise a plurality of accumulators which have different volumes and / or preload pressures. By connecting several accumulators to the throttle valve and designing them with different volumes and / or preload pressures, the damping device according to the invention can be adapted to handle oscillations with different frequencies and / or amplitudes.
    The damping device according to the invention may comprise a first throttle valve, which is connected to at least one first accumulator, and a second throttle valve, which is connected to at least one second accumulator. The area of the first flow cross-section of the first throttle valve and the area of the first flow cross-section of the second throttle valve may be different. Likewise, the area of the second flow cross-section of the first throttle valve and the area of the second flow cross-section of the second throttle valve may be different. The volume and / or the pre-charge pressure of the first accumulator (s) is further arranged to be different from the volume and / or the pre-charge pressure of the or the second accumulators. By adjusting the flow cross-section of the throttle valves and the volumes and preload pressures of the accumulators, the damping device according to the invention can be adapted to handle different oscillation characteristics.
    The at least one throttle valve may be a spring biased, pilot controlled 2/2 valve which includes a valve body movably disposed in a valve chamber between the first valve position and the second valve position, and a biased spring which actuates the valve body with a spring force which brings the valve body to one of the first valve position and the other valve position when the hydraulic pressure at that first valve port is equal to the hydraulic pressure at the second valve port. This ensures that the throttle valve does not end up in an indeterminate position as the pressure at the first valve port is equal to the pressure at the second valve port.
    P2122EN TXTO1 4 In the event of a change in flow direction of the hydraulic fluid, the throttle valve is preferably arranged to assume the new valve position immediately after the hydraulic fluid flow changes direction so that the throttle valve, in practice, performs a harder throttle during the hydraulic fluid flowing from the hydraulic fluid.
    "Hearth throttling" or "hearth damping" in this context means a throttling or damping achieved with a relatively small flow cross-section, and "soft throttling" or "soft damping" means a throttling or damping achieved with a relatively large flow cross-section. In other words, a "hard choke" has a lower flow cross section than a "soft choke".
    Compared with known damping devices, where throttle valves have a direction-independent throttle and which are thus equal regardless of the direction in which the hydraulic fluid passes, the damping device according to the invention makes it possible to achieve a "soft" damping during a first compression in the hydraulic system. when the hydraulic fluid initially flows into the accumulator, and then at the return flow, when the hydraulic fluid turns and slips out of the accumulator again, to produce a much "harder" damping and thereby slow down the return movement considerably. By varying in this way the fate through the throttle valve, ie. by combining a relatively "soft" compression throttle with a relatively "hard" return throttle, it is possible to achieve a previously difficult combination of "soft" and "hard" damping.
    The ratio of the first flow cross-section to the second flow cross-section is adapted to the desired damping characteristic, which in turn depends on the oscillation characteristics expected to occur in the hydraulic system. In some applications it may be desirable for the throttle valve to be designed so that the area of the second flow cross-section is significantly smaller than the area of the first flow cross-section. Certain applications can e.g. The desired attenuation characteristic is achieved if the area of the second flow cross-section is in the range 0.1% to 10% of the area of the first flow cross-section, which gives a relatively hard attenuation of the return flow. In other applications it may be desirable for the difference between the second and the first flow cross-section to be smaller, and in some applications the area of the second flow cross-section may sometimes be up to 90%, and sometimes more, of the area of the first P2122SE TXTO1 5 flow cross-section.
    Normally, however, in hydraulic systems where oscillations with low flows and low frequencies occur, the second flow cross section should generally be relatively small compared to hydraulic systems where oscillations with high flows and high frequencies occur. However, for most applications, the area of the second flow cross section is in the range of 0.1% to 90% of the area of the first flow cross section.
    The damping device according to the invention can advantageously be used for damping oscillations in hydraulic systems of work machines, especially forestry machines, construction machines and load handling machines, where oscillations in the hydraulic systems e.g. caused by mechanical loads on load arms and cranes, or on other machine components, e.g. on the work machine's cab when the work machine is driven in terrain.
    The invention will be described in more detail below with reference to the appended patent drawings, in which, unless otherwise indicated or implicit in the context, like reference numerals indicate like components.
    Figure 1 schematically shows a hydraulic diagram of a hydraulic system comprising a damping device according to a first embodiment of the invention.
    Figure 2 shows attenuation curves for an undamped system, an attenuated system, a critically attenuated system, and for a system attenuated with an attenuation device according to the invention.
    Figure 3 schematically shows a hydraulic diagram of a hydraulic system comprising a damping device according to a second embodiment of the invention.
    Figure 4 schematically shows a hydraulic diagram of a hydraulic system comprising a damping device according to a third embodiment of the invention.
    Figure 5 schematically shows a hydraulic diagram of a hydraulic system comprising a damping device according to a fourth embodiment of the invention.
    P2122EN TXTO1 6 Figure 1 shows a hydraulic system 1 which comprises a hydraulic cylinder 2 and a single damping device 3, which is arranged to dampen oscillations in the hydraulic system, somt.ex. may occur due to loads on the hydraulic cylinder 2. Hydraulic cylinder 2 edge.ex. be arranged between a chassis and a driver's cab of a forestry machine, and the damping device 3 may be arranged to dampen mechanical oscillations of the driver's cab which occur when the forestry machine is driven in terrain.
    The damping device 3, which is connected to the hydraulic cylinder 2 via a hydraulic line 4, comprises an accumulator 5 and a valve device 20. The valve device 20 is arranged between the hydraulic cylinder 2 and the accumulator 5 and is connected to the accumulator 5 via a hydraulic line 7.
    The accumulator 5 is arranged to act as a "spring" in the hydraulic system, i.e. arranged to accumulate hydraulic fluid when the pressure in the hydraulic system increases, e.g. as the load on the hydraulic cylinder 2 increases, and return the hydraulic fluid to the rest of the hydraulic system when the pressure drops again. The task of the valve device 20 is to regulate or the inlet and outlet of the brake hydraulic fluid to the accumulator 5 so that a suitable attenuation is achieved. the valve device.
    In the valve device 20, however, the throttling is controlled so that the valve device 20 provides a first throttling of the hydraulic fluid as it flows through the valve device 20 in a direction towards the accumulator 5, and a second throttling of the hydraulic fluid as it flows through the valve device 20 in a direction out of the accumulator 5. in the other direction, ie. out of the accumulator, is harder than the throttle in the first direction, i.e. towards the accumulator.
    In other words, the valve device 20 has a first flow resistance for the hydraulic fluid at a flow direction towards the accumulator 5 and a second flow resistance for the hydraulic fluid at a flow direction out of the accumulator 5, which second flow resistance is greater than the first flow resistance.
    In the embodiment shown, this is achieved by the valve device 20 comprising throttle valve 6, which is designed as a pilot-controlled 2/2 throttle valve, i.e. a throttle valve such as P2122EN TXTO1 7 has two (2) valve portsA and B, and two (2) valve positions or valve positions.The throttle valve 6 can e.g. comprise a valve body, which is arranged in a valve chamber so that it can be moved between the two valve positions.
    In principle, the throttle valve 6 is arranged to assume a first valve position when the hydraulic expression at the valve port A, PA, exceeds the hydraulic expression at the valve port B, PB, i.e. when PA> PB, and second valve position when the hydraulic pressure at the valve port B exceeds the hydraulic pressure at the valve port A, ie. then PA <PB.
    Figure 1, where the throttle valve 6 is in the second valve position, is illustrated by pilot lines, where a first pilot line 9 is arranged to sense the hydraulic expression at the valve port A and a second pilot line 10 is arranged to sense the hydraulic expression at the valve port B, the valve body being arranged to actuate to enter the first valve position when the hydraulic pressure in the pilot line 9 exceeds the hydraulic pressure in the pilot line 10 and the second valve position when the hydraulic pressure in the pilot line 10 exceeds the hydraulic pressure in the pilot line 9. In other words, the hydraulic pressure in the first pilot line 9 acts to move the valve body towards the first valve position. the pilot line 10 acts to move the valve body towards the second valve position, i.e. the valve position shown in Figure 1.
    It will be appreciated, however, that the throttle valve 6 need not necessarily include physical pilot lines. It is e.g. it is possible that the hydraulic expression at the valve ports Aoch B directly affects the valve body of the throttle valve. In such a throttle valve, the valve body has pressure surfaces which are exposed to the hydraulic fluid at the respective valve portA and B, so that the entry pressure difference between the valve ports brings the valve body to the respective valve position.
    The valve device 20 also comprises a direction-independent throttle valve 11, which is arranged in series with the adjustable throttle valve 6 between the valve port and the hydraulic line 4. By the throttle valve 11 is direction-independent, it is meant here that the throttle valve 11 has the same flow cross-section regardless of in which flow direction.
    In the first valve position the throttle valve 6 has in principle no throttling, while in the second valve position it has a flow cross-section which is smaller than the flow cross-section which the direction-independent throttle valve 11 has. Thus, when P2122EN TXT01 8 hydraulic fluid flows through the valve device 20 toward the accumulator 5, the hydraulic fluid passes only the direction-independent throttle valve 11, and then the hydraulic fluid flows through the valve device 20 toward the accumulator 5, the hydraulic fluid first passes the throttle valve and second throttle valve. the direction-independent throttle valve 11. Consequently, the flow cross-section of the hydraulic fluid is smaller when the hydraulic fluid flows in the direction from the accumulator than when it flows in the direction towards the accumulator. In other words, the valve device has a greater flow resistance for the hydraulic fluid when it flows out of the accumulator 5 than when it flows in towards the accumulator 5.
    In the embodiment shown, the throttle valve 6 is spring biased, i.e. it comprises a biased spring 8, which is arranged to actuate the valve body with a spring force which strives to bring the valve body to one of the valve positions. These are usually wide valves to avoid them ending up in an indeterminate position in case the hydraulic pressure on each side if the valve is equal. In the embodiment shown, the spring 8 acts on the valve body with a spring force which strives to bring the valve body to the second valve position, as shown in figure 1.
    This means that the throttle valve 6 in reality assumes the first valve position when PA> PB + APföfspänning, where APföfspänning is the pressure difference between the valve ports A and B which corresponds to the compressive force with which the spring force of the spring 6 affects the valve body. In other words, the throttle valve 6 assumes the first valve position only when the pressure in the first pilot line 9 affects the valve body by a force exceeding the common force with which the spring 8 and the pressure in the second pilot line 10 act on the valve body.
    By adjusting the preload of the spring 8 and the pressure surfaces of the pilot fluids on each side of the valve body, the throttle valve 6 can thus be adapted to switch between the two valve positions at a predetermined pressure difference APfi-cf. voltage between valve ports A and B, where a positive value of APfi- towards the second valve position, and where a negative value of APfi-y voltage means that the bias voltage tends to move the valve body towards the first valve position. In the throttle valve 6 according to the invention, however, a possible valve bias must be selected so that the throttle valve 6 occupies the first valve position during the majority of the time when hydraulic fluid flows through the throttle valve 6 towards the accumulator 5, and the second valve position during the bulk of the time. through the throttle valve 6 in the direction out of the accumulator 5. However, it is preferred that any valve bias is designed so that its biasing force is small and in practice completely negligible in comparison with the compressive forces with which the flowing hydraulic fluid affects the valve body. This means in practice that the throttle valve 6 will assume the first valve position when PA> PB and the second valve position when PA <PB.
    In connection with oscillations in hydraulic systems, it is common to speak in principle of undamped, damped and critically damped systems. In an undamped system, generated pressure oscillation or pressure shock continues to oscillate without damping. In a damped system, the pressure oscillation is damped to ebb out within a number of periods. In a critically attenuated system, the system returns to equilibrium as soon as possible without oscillation.
    Figure 2 shows damping curves where displacement D, representing the position or movement of a work machine, is shown as a function of time T. Curve 12 illustrates an unmuffled oscillation, curve 13 a slightly damped oscillation, curve 14 a critical damped oscillation, and curve 15 an attenuated oscillation, which oscillations have been initiated according to the output power or output pulse. However, by arranging the throttle valve so that flow cross-section varies in size depending on the direction in which the hydraulic fluid passes through the throttle valve, as has been described above, it is possible to improve the damping. Curve 16 illustrates an attenuation obtainable with the attenuation device according to the invention. As can be seen from the figure, it is possible for the co-damping device to provide a damping which is softer during the first compression and then, when the flow direction of the hydraulic fluid reverses and the hydraulic fluid is to exit the accumulator again, choke considerably harder and with other words slow down the return movement considerably. The valve device according to the invention thus combines in a previously difficult-to-achieve manner the behavior of a very soft damping and an extremely hard damping, as shown in curve 16, where the soft return of a damped swing is combined with a first, suitably selected, compression damping of a critically damped swing.
    It will be appreciated that the principle of the invention does not depend on the type of throttle valve. The throttle valve can in principle be of any type, as long as it gives the valve device a first, soft throttle of the hydraulic fluid during the main part of the time when hydraulic fluid flows towards the accumulator 5 and a second, harder throttling of the hydraulic fluid during the main part of the valve. the time when the hydraulic fluid flows in the direction out of the accumulator 5.
    It will be appreciated that the damping device 3, in addition to the accumulator 5 shown in Figure 1, may comprise one or more additional accumulators 17 connected to the throttle valve 6 in parallel with the accumulator 5, as shown in broken lines in Figure 1. The damper device comprises a plurality of accumulators, 5, 17. it may be advantageous if these are designed with different volumes and / or preload pressures, so that a wider attenuation spectrum of the attenuation device 3 is achieved.
    Figure 3 shows an alternative embodiment of a damping device 3 'according to the invention. The damping device 3 'has a valve device 21, which comprises a first throttle valve 6, which is connected to a first accumulator 5, and a second throttle valve 6', which is connected to a second accumulator 5 ', which throttle valves 6, 6' are each connected in series to a direction-independent throttle valve 11, 11 'and are adjustable in the same manner as described in connection with Figure 1, i.e. they are arranged to assume a first valve position when hydraulic fluid flows into the respective accumulator, or at least during the majority of the time when the hydraulic fluid flows into the accumulator, and another valve position when the hydraulic fluid flows out of the accumulator, or at least during the majority of the time the hydraulic fluid flows out . At least one of the throttle valves 6 and 6 'may comprise one or more additional accumulators 17, 17', which are connected to the throttle valve 6, 6 'parallel to the first and second accumulators 5, 5', as shown in broken lines in Figure 3.
    To obtain a wide attenuation spectrum, the throttle valves 6 and 6 'can be designed with different first and second flow cross-sections, and the accumulators 5, 5', 17, 17 'can be designed with different preload pressures and / or different volumes. In addition, the direction independent throttle valves 11 and 11 'can be designed with different flow cross sections.
    Figure 4 shows a further embodiment of a damping device 3 "according to the invention. The damping device 3" has a valve device 22, which comprises an adjustable throttle valve 23, which is connected between the accumulator 5 and the hydraulic line P2122EN TXTO1 1 1 4 and is adjustable in the same manner as described in connection with Figure 1, i.e. it is arranged to assume a first valve position when hydraulic fluid flows towards the accumulator 5, or at least during the majority of the time when the hydraulic fluid flows into the counter-accumulator 5, and a second valve position when the hydraulic fluid flows out of the accumulator, or at least during the majority of the time when hydraulic flows the accumulator.
    However, the valve device 22 lacks the direction-independent throttle valve 11 described above. Instead, in addition to a reduced flow cross-section in its second valve position, the throttle valve 23 also has a reduced flow cross-section in its first valve position, which flow cross-section is larger than the flow cross-section in the second valve position. Thus, the valve device 22 also has a greater flow direction. than at the direction of flow towards the accumulator 5.
    Unlike the previously described throttle valve 6, the throttle valve 23 is biased towards the first valve position, i.e. the throttle valve 23 is arranged to assume the first valve position when the hydraulic pressure at the first valve port A is equal to the co-hydraulic pressure at the second valve port B.
    Figure 5 shows a further embodiment of a damping device 3 "'according to the invention. The damping device 3"' has a valve device 24, which comprises non-return valve 25, a first throttle valve 26 connected in series with the non-return valve 25 and a second independent throttle valve 27 connected in parallel with the non-return valve 25. the first throttle valve 26 has a flow cross-section which is larger than the flow cross-section of the second throttle valve 27. The check valve 25 is arranged to allow flow of hydraulic fluid in the direction of the accumulator 5, but to block the flow of hydraulic fluid in the direction of the hydraulic fluid. 27 at flow out of the accumulator 5 but not at flow into the accumulator 5, and consequently the valve device 24 will have a greater flow resistance for the hydraulic fluid at a direction of discharge out of the accumulator than at the direction of fate towards the accumulator.
    For the supply of hydraulic fluid, the hydraulic system 1 comprises in a known manner a hydraulic pump and related equipment which is connected to the hydraulic line and in which figures 1 and 3 P2122EN TXTO1 1 2 are marked P in. Such equipment is known per se and will not be described in more detail here.
    The invention has been described above on the basis of a number of possible embodiments. However, those skilled in the art will appreciate that other embodiments, or variants thereof, are possible within the scope of the appended claims.
    P2122SE TXTO1 1 3
    权利要求:
    Claims (17)
    [1]
    Requirements
    [2]
    A damping device (3, 3 ', 3 ", 3"') for damping oscillations in a hydraulic system (1) of a working machine, which damping device (3, 3 ', 3 ", 3"') comprises at least one accumulator (5 , 5 ', 17, 17') for accumulating the hydraulic fluid system hydraulic system (1), and a valve device (20, 21, 22) connected between said at least one accumulator (5, 5 ', 17, 17') and the hydraulic system (1). 24), characterized in that the valve device (20, 21, 22, 24) has a first fate resistance for the hydraulic fluid during the majority of the time when hydraulic fluid flows through the valve device (20, 21, 22, 24) in the direction towards said minimum accumulator (5, 5 ', 17, 17'), and a second flow resistance for hydraulic fluid during the majority of the time the hydraulic fluid flows through the valve device (20, 21, 22, 24) in the direction out of said at least one accumulator (5, 5 ', 17, 17'). ), which other flow resistance is greater than the first flow resistance.
    [3]
    Damping device (3, 3 ', 3 ") according to claim 1, characterized in that the valve device (20, 21, 22) comprises at least one adjustable throttle valve (6, 6', 23), which comprises a first valve port (A) for connection to the hydraulic system (1) and another valve port (B), which is connected to the at least one accumulator (5, 5 ', 17, 17'), which at least one throttle valve (6, 6 ', 23) comprises a first valve position, which has a first flow cross-section, and a second valve position, which has a second flow cross-section, which second flow cross-section is smaller than the first flow cross-section, which at least one throttle valve (6, 6 ', 23) is arranged to assume the first valve position during the majority of the time the throttle valve is rotated. (6, 6 ', 23) in the direction of said at least one accumulator (5, 5', 17, 17 '), and the second valve position for the majority of the time when hydraulic fluid flows through the throttle valve (6, 6', 23) in direction out of said at least one accumulator (5, 5 ', 17, 17').
    [4]
    Damping device (3, 3 ', 3 ") according to claim 2, characterized in that said at least one throttle valve (6, 6', 23) is arranged to assume the first valve position when
    [5]
    5. PA> PB + Monkey bias
    [6]
    6. P2122EN TXTO1 1 4 and the other valve position then
    [7]
    7. PA <PB + Ap bias voltage where PA is the hydraulic pressure at the first valve port (A), PB is the hydraulic pressure at the second valve port (B), and APfi equal voltage is a pressure difference between the first valve port (A) and the second valve port (B) which corresponds to a pressure force with which a predetermined bias of the throttle valve (6, 6 ', 23) acts on the valve body. Damping device (3, 3 ', 3 ") according to claim 3, characterized in that the bias voltage is arranged to be negligible in comparison with the compressive forces with which the hydraulic fluid flowing through the throttle valve (6, 6', 23) acts on the valve body, the throttle valve (6 , 6 ', 23) is arranged to assume the first valve position when the hydraulic pressure at the first valve port (A) is higher than the hydraulic pressure at the second valve port (B), and the second valve position when the hydraulic pressure at the second valve port (B) is higher than the hydraulic pressure at damping device (3, 3 ', 3 ") according to any one of claims 2-4, characterized in that the area of the second flow cross-section is in the range 0.1% to 90% of the area of the first flow cross-section. Damping device (3, 3 ', 3 ") according to any one of the preceding claims, characterized in that said at least one accumulator (5, 5', 17, 17 ') comprises a plurality of accumulators having different volumes and / or pre-charge pressures. Damping device ( 3 ') according to any one of claims 2-6, characterized in that said at least one throttle valve (6, 6') comprises a first throttle valve (6), which is connected to at least a first accumulator (5, 17), and a second throttle valve ( 6 '), which is connected to at least one second accumulator (5', 17 '). Damping device (3') according to claim 7, characterized in that the area of the first flow cross-section of the first throttle valve (6) and the area of the first flow cross-section of the second throttle valve (6 ') are different.
    [8]
    8. P2122SE TXTO1 1 5
    [9]
    Damping device (3 ') according to one of Claims 7 and 8, characterized in that the area of the second flow cross section of the first throttle valve (6) and the area of the second flow cross section of the second throttle valve (6') are different.
    [10]
    Damping device (3 ') according to any one of claims 7-9, characterized in that the pre-discharge pressure and / or the volume of said at least one first accumulator (5,17) is different from the pre-charge pressure and / or the volume of said at least one second accumulator (5' , 17 ').
    [11]
    Damping device (3, 3 ', 3 ") according to any one of claims 2-10, characterized in that said at least one throttle valve (6, 6', 23) is a spring-biased, pilot-controlled 2/2 valve which comprises a valve body which is movable arranged in a valve chamber between the first valve position and the second valve position, and a biased spring (8), which actuates the valve body with a spring force, which brings the valve body to the first valve position or the second valve position when the hydraulic pressure at the first valve port (A) is equal to the hydraulic pressure at the other valve port (B).
    [12]
    Work machine comprising a hydraulic system (1), characterized in that it comprises a damping device (3, 3 ', 3 "3") according to any one of the preceding claims for damping oscillations in the hydraulic system (1).
    [13]
    Work machine according to claim 12, characterized in that the damping device (3, 3 ', 3 ", 3"') is arranged to damp heeling of a cab of the work machine.
    [14]
    Work machine according to one of Claims 12 and 13, characterized in that the work machine is one of a forestry machine, a construction machine and a load handling machine.
    [15]
    A method for damping oscillations in a hydraulic system (1) of a working machine with a damping device (3, 3 ', 3 ", 3"'), which damping device (3, 3 ', 3 ", 3"') comprises at least one accumulator (5, 5 ', 17, 17') for accumulating hydraulic fluid of the hydraulic system (1), and a valve device (20, 21) connected between said at least one accumulator (5, 5 ', 17, 17') and the hydraulic system (1). 22, 24), characterized by the steps: - that the damping device (3, 3 ', 3 ", 3"') is caused to exhibit a first resistance resistance of the hydraulic fluid for the majority of the time when the hydraulic fluid flows through the valve device (20, 21). , 22, 24) in the direction of said at least one accumulator (5, 5 ', 17, 17'), and that the damping device (3, 3 ', 3 ", 3"') is caused to have a second fl resistance resistor for the hydraulic fluid during the main part of the time when the hydraulic fluid flows through the valve device (20, 21, 22, 24) in the direction out of said at least one accumulator (5, 5 ', 17, 17'), which second flow tooth is greater than the first flow resistance.
    [16]
    A method according to claim 15, wherein the damping device (3, 3 ', 3 ") comprises at least one throttle valve (6, 6', 23) connected to said at least one accumulator (5, 5 ', 17, 17'). , which at least one throttle valve (6, 6 ', 23) comprises a first valve port (A) connected to the hydraulic system (1) and a second valve port (B) connected to the at least one accumulator (5, 5', 17, 17 '). , characterized by the steps: that the at least one throttle valve (6, 6 ', 23) is caused to assume a first valve position, which has a first flow cross-section, for the majority of the time when hydraulic fluid flows through the throttle valve (6, 6', 23) in the direction towards said at least one accumulator (5, 5 ', 17, 17'), and that said at least one throttle valve (6, 6 ', 23) is caused to assume a second valve position, which has a second flow cross-section, for the majority of the time then hydraulic fluid flows through the throttle valve (6, 6 ', 23) in the direction out of the at least one accumulator (5, 5', 17, 17 '), which other flow cross section is smaller than the first flow cross section.
    [17]
    Method according to one of Claims 15 and 16, characterized in that it is carried out with a damping device (3, 3 ', 3 ", 3"') according to one of Claims 1 to 11. P2122SE TXTO1 17
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    同族专利:
    公开号 | 公开日
    FI20175809A|2018-03-13|
    SE541927C2|2020-01-07|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    SE1651226A|SE541927C2|2016-09-12|2016-09-12|Damping device|SE1651226A| SE541927C2|2016-09-12|2016-09-12|Damping device|
    FI20175809A| FI20175809A|2016-09-12|2017-09-12|Damping|
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