Cylinder device

Abstract

To provide a cylinder device capable of generating appropriate thrust according to kinetic viscosity of operation liquid in the cylinder device.SOLUTION: A cylinder device 1 comprises: a hydraulic cylinder A having a cylinder body 2 expanded / contracted by supply of an operation fluid, a pump 13 for supplying the operation fluid to the cylinder body 2, and a motor 14 for driving the pump 13, and capable of functioning as an actuator by driving of the pump 13 and functioning as a passive dumper when the pump 13 is stopped; and a controller C for controlling the motor 14, wherein the controller C comprises: a torque detection part 42 for detecting torque Tm of the motor 14; and a selecting part 44 for selecting either one of an actuator mode for making the hydraulic cylinder A function as the actuator and a passive dumper mode for making it function as the passive dumper on a basis of the torque Tm detected by the torque detection part 42.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an improvement in a cylinder device. [Background technology]

[0002] Conventionally, this type of cylinder device has been used in various machines, vehicles, etc., and for example, in railway vehicles, it is used by being interposed between the car body and the bogie to suppress vibrations in the left-right direction relative to the direction of travel of the car body.

[0003] More specifically, the cylinder device includes a cylinder connected to one of the bogie and carbody of the railway vehicle, a piston slidably inserted into the cylinder, a rod inserted into the cylinder and connected to the other of the piston, the bogie, and the carbody, a rod-side chamber and a piston-side chamber separated by the piston within the cylinder, a tank, a first on-off valve provided midway through a first passage connecting the rod-side chamber and the piston-side chamber, a second on-off valve provided midway through a second passage connecting the piston-side chamber and the tank, a pump that supplies hydraulic oil to the rod-side chamber, a discharge passage connecting the rod-side chamber to the tank, a variable relief valve provided midway through the discharge passage and capable of changing the valve opening pressure, a hydraulic cylinder equipped with a motor that drives the pump, and a controller that controls the motor and each valve.The motor drives the pump to supply hydraulic oil into the cylinder, generating thrust and suppressing vibration of the carbody.

[0004] When such a cylinder device functions as an actuator, the pump is driven at a constant rotational speed to supply hydraulic oil into the cylinder and the valve opening pressure of the adjustable relief valve is adjusted to generate the desired thrust. However, when a railway vehicle is used on a route in a cold region, the hydraulic oil in the hydraulic cylinder becomes extremely cold and the kinetic viscosity of the hydraulic oil increases. Therefore, if the rotational speed of the pump is kept constant, pressure loss increases due to the adjustable relief valve, pipeline resistance, etc., causing the pressure in the cylinder to become too high, resulting in excessive thrust and a deterioration in the ride comfort of the vehicle.

[0005] Therefore, in conventional cylinder devices, the temperature of the hydraulic oil is estimated from date, location information, etc., and if it is determined that the temperature of the hydraulic oil is lower than a predetermined temperature, the rotation speed of the pump is reduced to prevent the thrust of the cylinder device from becoming excessive (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-1305 Summary of the Invention [Problem to be solved by the invention]

[0007] In conventional cylinder devices, excessive thrust is prevented by changing the pump rotation speed according to the temperature of the hydraulic oil, so the temperature of the hydraulic oil is estimated using date or location information, or the oil temperature is detected.However, since it is not possible to grasp the actual dynamic viscosity of the hydraulic oil, it may not be possible to respond to changes in the dynamic viscosity of the actual hydraulic oil and may not be able to generate appropriate thrust, which leaves room for improvement in the ride comfort of the vehicle.

[0008] Conventional cylinder devices have the problem that it is difficult to generate appropriate thrust in response to changes in the dynamic viscosity of the working fluid inside the hydraulic cylinder. Even when the cylinder device is used in equipment other than railway vehicles that requires vibration suppression, the same problem occurs when the equipment is used in cold climates.

[0009] Therefore, an object of the present invention is to provide a cylinder device that can generate an appropriate thrust in response to changes in the kinetic viscosity of the working fluid in the cylinder device. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the cylinder device of the present invention comprises a hydraulic cylinder having a cylinder body that expands and contracts when hydraulic fluid is supplied to the cylinder body, a pump that supplies hydraulic fluid to the cylinder body, and a motor that drives the pump, and can function as an actuator when the pump is driven and can also function as a passive damper when the pump is stopped, and a controller that controls the motor, and the controller has a torque detection unit that detects the torque of the motor, and a selection unit that selects either an actuator mode in which the hydraulic cylinder functions as an actuator or a passive damper mode in which the hydraulic cylinder functions as a passive damper based on the torque detected by the torque detection unit.

[0011] According to a cylinder device configured in this manner, one of the actuator mode and the passive mode is selected based on the motor torque, which changes according to the kinetic viscosity of the working fluid in the hydraulic cylinder. This makes it possible to accurately determine whether the actuator mode or the passive damper mode is more suitable for the current kinetic viscosity of the working fluid, and to generate an appropriate thrust in response to changes in the kinetic viscosity of the working fluid.

[0012] The controller in the cylinder device may also have a rotation speed determination unit that determines the rotation speed of the motor based on the torque.

[0013] With this cylinder device, when the hydraulic cylinder functions as an actuator, the motor can be driven at a rotation speed appropriate for the kinetic viscosity of the hydraulic fluid, preventing the hydraulic cylinder from outputting excessive thrust. Furthermore, even when feedback control of the hydraulic cylinder's thrust is attempted, excessive thrust is prevented even if the kinetic viscosity of the hydraulic fluid is high, reducing the error between the target thrust and the actual thrust output, and reducing hunting, which is an oscillatory phenomenon in the hydraulic cylinder's thrust.

[0014] Furthermore, the controller in the cylinder device may cause the hydraulic cylinder to function as a passive damper when the torque is equal to or greater than a first torque threshold, drive the motor at a low rotation speed to cause the hydraulic cylinder to function as an actuator when the torque is less than the first torque threshold and equal to or greater than a second torque threshold that is lower than the first torque threshold, and drive the motor at a normal rotation speed that is higher than the low rotation speed to cause the hydraulic cylinder to function as an actuator when the torque is less than the second torque threshold.

[0015] With the cylinder device configured in this manner, by setting a first torque threshold and a second torque threshold for torque and comparing the torque with these first and second torque thresholds, it is possible to easily switch between actuator mode and passive damper mode and switch the motor rotation speed, thereby generating an appropriate thrust according to the dynamic viscosity of the working fluid.

[0016] In addition, the controller in the cylinder device may have an average value calculation unit that calculates the average value of torque detected over a predetermined time period after the motor is started from a stopped state, and the selection unit may select one of the actuator mode and the passive damper mode based on the average value of torque.

[0017] In a cylinder device configured in this manner, the selection unit uses the average torque value to function as either the actuator mode or the passive damper mode, so that even if the torque detected by the torque detection unit fluctuates, it is possible to accurately select whether the actuator or the passive damper is more suitable for the dynamic viscosity of the hydraulic oil, and the selection process can be completed in a short time.

[0018] Furthermore, the hydraulic cylinder in the cylinder device may be interposed between the bogie and the car body of the railway vehicle, and the selection unit may select one of the actuator mode and the passive damper mode when the railway vehicle remains stopped for a predetermined stopping time.

[0019] In a cylinder device configured in this manner, the selection unit executes the selection process when the railway vehicle remains stopped for a predetermined period of time, so that the selection process can be executed when the railway vehicle stops at a station, etc., and the selection process is performed in a timely manner to allow the hydraulic cylinder to function as one of the actuator and passive damper that is suited to the dynamic viscosity of the working fluid, thereby improving the ride comfort of the vehicle. [Effects of the Invention]

[0020] According to the cylinder device of the present invention, it is possible to generate a thrust appropriate for the kinetic viscosity of the working fluid in the cylinder device. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a diagram showing a cylinder device according to an embodiment installed in a railway vehicle; [Figure 2] FIG. 2 is a circuit diagram of an actuator in the cylinder device according to the embodiment. [Figure 3] FIG. 2 is a configuration diagram of a controller in the cylinder device according to the embodiment. [Figure 4] 10 is a flowchart showing a procedure for a controller selection process in the cylinder device according to the embodiment. [Figure 5] 4 is a flowchart showing a procedure of control processing of a hydraulic cylinder by a controller in the cylinder device of one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be described below based on the embodiments shown in the drawings. A cylinder device 1 in one embodiment is used as a vibration damping device for a car body B of a railway vehicle V, and is configured to include a hydraulic cylinder A interposed between a bogie T and the car body B of the railway vehicle, and a controller C, as shown in Figure 1.

[0023] More specifically, hydraulic cylinder A has one end connected to bogie T and the other end connected to pin P hanging down below car body B, and is installed between bogie T and car body B of railway vehicle V, and suppresses vibration of car body B by the thrust it exerts. Note that cylinder device 1 may also be used in equipment other than railway vehicles that requires vibration suppression.

[0024] Below, we will explain in detail each part of the cylinder device 1. First, we will explain the hydraulic cylinder A. The hydraulic cylinder A includes a cylinder body 2 that expands and contracts when hydraulic fluid is supplied, a pump 13 that supplies hydraulic fluid to the cylinder body 2, and a motor 14 that drives the pump 13. The hydraulic cylinder A can function as an actuator when the pump 13 is driven, and can also function as a passive damper when the pump 13 is stopped.

[0025] 2 , the hydraulic cylinder A is configured as a single-rod actuator and includes: a cylinder 3, a piston 4 slidably inserted into the cylinder 3, a rod 5 inserted into the cylinder 3 and connected to the piston 4, a rod-side chamber 6 and a piston-side chamber 7 partitioned by the piston 4 within the cylinder 3, a tank 8, a first on-off valve 10 provided in a first passage 9 connecting the rod-side chamber 6 and the piston-side chamber 7, a second on-off valve 12 provided in a second passage 11 connecting the piston-side chamber 7 and the tank 8, a pump 13 that supplies liquid to the rod-side chamber 6 within the cylinder 3, a motor 14 that drives the pump 13, a discharge passage 21 connecting the rod-side chamber 6 and the tank 8, and a pressure control valve 22 provided in the discharge passage 21 to adjust the pressure within the cylinder 3. The rod-side chamber 6 and the piston-side chamber 7 are filled with hydraulic oil as a hydraulic fluid, and the tank 8 is filled with gas in addition to the hydraulic oil. Although the hydraulic fluid used in the hydraulic cylinder A in this embodiment is hydraulic oil, the hydraulic fluid may be an antifreeze liquid instead of hydraulic oil.

[0026] When the pump 13 is driven with the first passage 9 in a connected state by the first on-off valve 10 and the second on-off valve 12 in a closed state, the hydraulic cylinder A generates a thrust in the extension direction, and when the pump 13 is driven with the second passage 11 in a connected state by the second on-off valve 12 and the first on-off valve 10 in a closed state, the hydraulic cylinder A generates a thrust in the contraction direction.

[0027] Each part of the hydraulic cylinder A will be described in detail below. The cylinder 3 is cylindrical, and its right end in FIG. 2 is closed by a lid 15, and an annular rod guide 16 is attached to its left end in FIG. 2. A rod 5, which is inserted movably into the cylinder 3, is slidably inserted into the rod guide 16. One end of the rod 5 protrudes outside the cylinder 3, and the other end inside the cylinder 3 is connected to a piston 4, which is also inserted slidably into the cylinder 3.

[0028] The gap between the outer periphery of the rod 5 and the cylinder 3 is sealed by a sealing member (not shown), thereby maintaining the inside of the cylinder 3 in an airtight state. The rod-side chamber 6 and the piston-side chamber 7, which are partitioned by the piston 4 inside the cylinder 3, are filled with hydraulic oil as a liquid, as described above. Although not shown in detail, the hydraulic cylinder A also includes an outer cylinder 23 that is cylindrical and covers the outer periphery of the cylinder 3, with both open ends closed by the lid 15 and the rod guide 16, respectively, to form a tank 8 between the cylinder 3 and the outer cylinder 23, and the tank 8 is provided integrally with the cylinder body 2. The tank 8 is filled with hydraulic oil as a liquid and gas.

[0029] In addition, the cover 15 that closes the left end of the rod 5 and the right end of the cylinder 3 in Figure 2 is provided with an attachment portion not shown, and the attachment portion not shown connects the rod 5 of the hydraulic cylinder A to the bogie T of the railway vehicle V and connects the cylinder 3 to the car body B, so that the hydraulic cylinder A can be interposed between the bogie T and the car body B.

[0030] The rod-side chamber 6 and the piston-side chamber 7 are connected by a first passage 9, and a first on-off valve 10 is provided in the middle of this first passage 9. This first passage 9 connects the rod-side chamber 6 and the piston-side chamber 7 outside the cylinder 3, but may be provided in the piston 4.

[0031] In this embodiment, the first on-off valve 10 is an electromagnetic on-off valve, and is configured to include a valve element 10a having a communication position 10b that opens the first passage 9 to communicate between the rod side chamber 6 and the piston side chamber 7 and a blocking position 10c that blocks communication between the rod side chamber 6 and the piston side chamber 7, a spring 10d that urges the valve element 10a to take the blocking position 10c, and a solenoid 10e that switches the valve element 10a to the communication position 10b against the spring 10d when energized.

[0032] The piston-side chamber 7 and the tank 8 are connected to each other via a second passage 11, and a second on-off valve 12 is provided in the middle of this second passage 11. In this embodiment, the second on-off valve 12 is an electromagnetic on-off valve, and is configured to include a valve element 12a having a communication position 12b that opens the second passage 11 to connect the piston-side chamber 7 and the tank 8 and a blocking position 12c that blocks communication between the piston-side chamber 7 and the tank 8, a spring 12d that urges the valve element 12a to the blocking position 12c, and a solenoid 12e that switches the valve element 12a to the communication position 12b against the spring 12d when energized.

[0033] The pump 13 is driven by a motor 14. The pump 13 is a pump that discharges liquid in only one direction, and its discharge port is connected to the rod-side chamber 6 via a supply passage 17, and its suction port is connected to the tank 8. When the pump 13 is driven by the motor 14, it sucks liquid from the tank 8 and supplies the liquid to the rod-side chamber 6.

[0034] As described above, the pump 13 discharges liquid in only one direction and does not switch its rotation direction, so there is no problem of the discharge amount changing when the rotation direction is switched, and an inexpensive gear pump or the like can be used. Furthermore, because the rotation direction of the pump 13 is always the same, the motor 14, which is the drive source that drives the pump 13, does not require high responsiveness to rotation switching, so that an inexpensive motor 14 can be used. Note that a check valve 18 is provided in the supply passage 17 to prevent backflow of liquid from the rod side chamber 6 to the pump 13.

[0035] In this embodiment, the rod side chamber 6 and the tank 8 are connected through a discharge passage 21, and a pressure control valve 22 capable of changing the valve opening pressure is provided midway through this discharge passage 21.

[0036] The pressure control valve 22 is a variable relief valve that is biased in the direction of opening by upstream pressure, and includes a valve element 22a provided in the middle of the discharge passage 21, a spring 22b that biases the valve element 22a so as to block the discharge passage 21, and a proportional solenoid 22c that generates a thrust against the spring 22b when current is applied, and the valve opening pressure can be adjusted by adjusting the amount of current flowing through the proportional solenoid 22c. Note that the pressure control valve 22 may be a valve other than a variable relief valve as long as it is capable of adjusting the upstream pressure.

[0037] When the pressure in the rod side chamber 6 in the cylinder 3, which is upstream of the discharge passage 21 that acts on the valve element 22a, exceeds the relief pressure (valve opening pressure), the resultant force of the force urging the valve element 22a in the opening direction due to the pressure in the rod side chamber 6 and the force of the proportional solenoid 22c pushing the valve element 22a exceeds the force of the spring 22b that urges the valve element 22a, and the valve element 22a opens to open the discharge passage 21.

[0038] In addition, the thrust applied by the proportional solenoid 22c to the valve body 22a can be adjusted by adjusting the amount of current supplied to the proportional solenoid 22c, and the pressure control valve 22 minimizes the valve opening pressure when the amount of current supplied to the proportional solenoid 22c is maximized, and conversely, maximizes the valve opening pressure when no current is supplied to the proportional solenoid 22c at all.

[0039] Note that, regardless of the open / closed states of the first on-off valve 10 and the second on-off valve 12, when an excessive input in the extension / contraction direction is applied to the hydraulic cylinder A and the pressure in the rod side chamber 6 exceeds the valve opening pressure, the pressure control valve 22 opens to communicate the rod side chamber 6 with the tank 8 through the discharge passage 21, thereby preventing the pressure in the rod side chamber 6 from becoming excessive and protecting the entire system of the hydraulic cylinder A.

[0040] Moreover, the hydraulic cylinder A in the cylinder device 1 of this embodiment is provided with a flow rectification passage 19 that connects the piston side chamber 7 and the rod side chamber 6, and a suction passage 20 that connects the tank 8 and the piston side chamber 7.

[0041] The rectification passage 19 is provided with a check valve 19a in the middle, and is set as a one-way passage that only allows liquid to flow from the piston-side chamber 7 to the rod-side chamber 6. Furthermore, the suction passage 20 is provided with a check valve 20a in the middle, and is set as a one-way passage that only allows liquid to flow from the tank 8 to the piston-side chamber 7. Note that the rectification passage 19 may be integrated into the first passage 9 by using the shutoff position 10c of the first on-off valve 10 as a check valve, and the suction passage 20 may be integrated into the second passage 11 by using the shutoff position 12c of the second on-off valve 12 as a check valve.

[0042] When the hydraulic cylinder A configured as described above is to exert a desired thrust in the extension direction, the first on-off valve 10 is set to the communication position 10b, the second on-off valve 12 is set to the shut-off position 12c, and the motor 14 is rotated at a constant speed while the pump 13 supplies fluid into the cylinder 3. In this manner, the rod-side chamber 6 and the piston-side chamber 7 are placed in communication with each other, and fluid is supplied from the pump 13 to the rod-side chamber 6 and the piston-side chamber 7. This pushes the piston 4 to the left in FIG. 2 , causing the hydraulic cylinder A to exert thrust in the extension direction. When the pressure in the rod-side chamber 6 and the piston-side chamber 7 in the cylinder 3 exceeds the valve opening pressure of the pressure control valve 22, the pressure control valve 22 opens, and the fluid in the cylinder 3 moves to the tank 8 via the discharge passage 21. Therefore, the pressure in the cylinder 3 is adjusted by the pressure control valve 22 to be equal to the valve opening pressure of the pressure control valve 22. Furthermore, hydraulic cylinder A generates a thrust that pushes piston 4 leftward in FIG. 2 because the pressure-receiving area of ​​the piston 4 on the piston side chamber side facing piston side chamber 7 is larger than the pressure-receiving area of ​​the piston 4 on the rod side chamber side facing rod side chamber 6 by the cross-sectional area of ​​the rod 5. In this way, hydraulic cylinder A can generate a thrust that drives pump 13 to extend cylinder body 2, and this thrust is equal to the cross-sectional area of ​​rod 5 multiplied by the valve opening pressure of pressure control valve 22. Therefore, by adjusting the valve opening pressure of pressure control valve 22, the thrust in the extension direction generated by hydraulic cylinder A can be adjusted.

[0043] On the other hand, when hydraulic cylinder A is to exert a desired thrust in the contraction direction, the first on-off valve 10 is set to the shutoff position 10c, the second on-off valve 12 is set to the communication position 12b, and liquid is supplied from the pump 13 to the rod side chamber 6 while the motor 14 is rotating at a constant speed. In this manner, the piston side chamber 7 and the tank 8 are placed in communication with each other, and liquid is supplied from the pump 13 to the rod side chamber 6, so that the piston 4 is pushed to the right in FIG. 2 and hydraulic cylinder A exerts a contraction thrust. In this manner, hydraulic cylinder A can drive the pump 13 to generate thrust that contracts the cylinder body 2. If the pressure in the tank 8 is considered to be zero, this thrust is equal to the value obtained by multiplying the pressure-receiving area of ​​the piston 4 facing the rod side chamber 6 by the valve opening pressure of the pressure control valve 22. The pressure in the rod side chamber 6 can be adjusted by adjusting the amount of current to the pressure control valve 22, and therefore the thrust in the contraction direction generated by hydraulic cylinder A can be adjusted.

[0044] In the case of this hydraulic cylinder A, the cross-sectional area of ​​the rod 5 is half that of the piston 4, and the pressure-receiving area on the rod side chamber 6 side of the piston 4 is half that of the piston side chamber 7 side, so that if the pressure in the rod side chamber 6 is the same during extension and retraction, the thrust generated in both extension and retraction will be equal, and the flow rate relative to the displacement of the hydraulic cylinder A will also be the same on both the extension and retraction sides. Therefore, when controlling the thrust of the hydraulic cylinder A, if the magnitude of the thrust in the extension direction and the retraction direction is the same, the amount of current applied to the pressure control valve 22 will also be the same, which simplifies the control of the hydraulic cylinder A, and in addition, the flow rate relative to the displacement of the hydraulic cylinder A will also be the same, which has the advantage of providing the same responsiveness on both the extension and retraction sides.

[0045] Furthermore, since the hydraulic cylinder A of this embodiment is equipped with the rectifying passage 19 and the suction passage 20, when the first on-off valve 10 and the second on-off valve 12 are both in the shutoff positions 10c, 12c, the rod-side chamber 6, the piston-side chamber 7, and the tank 8 are connected in a daisy-chain manner through the rectifying passage 19, the suction passage 20, and the discharge passage 21, and the hydraulic cylinder A functions as a uniflow damper. Therefore, in the event of a failure in which current cannot be applied to the motor 14, the first on-off valve 10, the second on-off valve 12, and the pressure control valve 22 of the hydraulic cylinder A, the valve bodies 10a, 12a of the first on-off valve 10 and the second on-off valve 12 are pressed by the springs 10d, 12d, and the valve bodies 10c, 12c are respectively in the shutoff positions 10c, 12c, and the pressure control valve 22 functions as a pressure control valve with the valve opening pressure fixed at the maximum, so that the hydraulic cylinder A automatically functions as a passive damper.

[0046] When the motor 14 is stopped and the pump 13 is not driven, the hydraulic cylinder A can generate a damping force only when extending or contracting with only one of the first on-off valve 10 and the second on-off valve 12 open. In this way, the hydraulic cylinder A can generate a damping force of a desired magnitude only in a desired direction, and can therefore function as a semi-active damper.

[0047] As described above, the hydraulic cylinder A can function as an actuator by driving the pump 13, can function as a passive damper when the pump 13 is stopped, and can also function as a semi-active damper by controlling the first on-off valve 10, the second on-off valve 12, and the pressure control valve 22 even when the pump 13 is stopped. Note that the hydraulic cylinder A may have a structure other than that described above as long as it can function as an actuator that can extend and retract the cylinder body 2 by driving the pump 13, and can generate a thrust that hinders extension and retraction when the cylinder body 2 is extended and retracted by an external force while the pump 13 is stopped.

[0048] 3, the controller C of this embodiment includes an acceleration sensor 40 that detects an acceleration α of the vehicle body B in a horizontal lateral direction relative to the vehicle traveling direction, a target thrust calculation unit 41 that calculates a target thrust of the hydraulic cylinder A, a torque detection unit 42 that detects the torque of the motor 14, an average value calculation unit 43 that calculates an average value Tma of the torque Tm detected by the torque detection unit 42, a selection unit 44 that selects whether to cause the hydraulic cylinder A to function as an actuator or as a passive damper based on the average value Tma of the torque Tm calculated by the average value calculation unit 43, and a control unit 45 that calculates a target thrust of the hydraulic cylinder A based on the selection result of the selection unit 44 and the average value Tma of the torque Tm. a motor control unit 46 that controls the motor 14; a pressure control valve control unit 47 that controls the pressure control valve 22; a first on-off valve control unit 48 that controls the first on-off valve 10; a second on-off valve control unit 49 that controls the second on-off valve 12; and a control command generation unit 50 that outputs control commands to the motor control unit 46, the pressure control valve control unit 47, the first on-off valve control unit 48, and the second on-off valve control unit 49 based on the target thrust of the target thrust calculation unit 41, the selection result of the selection unit 44, and the speed of the railway vehicle V, and is installed on the car body B of the railway vehicle V as shown in FIG. 1.

[0049] Hereinafter, a detailed description will be given of each part of the controller C. The acceleration sensor 40 detects the acceleration α of the vehicle body B in the horizontal lateral direction relative to the vehicle traveling direction, and inputs it to a target thrust calculation unit 41.

[0050] The target thrust calculation unit 41 filters out the steady-state acceleration, drift components, and noise that are contained in the acceleration α when traveling around a curve, then integrates the filtered acceleration α to determine the lateral speed of the vehicle body B, and multiplies the determined speed by the skyhook damping coefficient to determine the thrust that should be output from the hydraulic cylinder A. For example, if the thrust is in a direction that pushes the vehicle body B leftward in FIG. 1, the target thrust calculation unit 41 determines the target thrust as a positive value, and conversely, if the thrust is in a direction that pushes the vehicle body B rightward in FIG. 1, the target thrust calculation unit 41 determines the target thrust as a negative value, and inputs a command indicative of the determined target thrust to the control command generation unit 50.

[0051] While the target thrust calculation unit 41 has determined the target thrust in accordance with the skyhook control law as described above, it may also determine the target thrust using a control law other than the skyhook control law; for example, it may extract a component of a resonance frequency band in the carbody B of the railway vehicle V from the acceleration α, and weight the extracted component of the resonance frequency band of the acceleration α by frequency to perform H∞ control of the target thrust that suppresses vibration of the carbody B. Furthermore, the target thrust calculation unit 41 may be configured to provide acceleration sensors 40 at the front and rear of the carbody B to grasp sway vibration, which is a lateral vibration of the carbody B, and yaw vibration, which is a vibration in a rotational direction about the center of gravity of the carbody B, and determine the resultant force of the thrust that suppresses sway vibration and the thrust that suppresses yaw vibration as the target thrust to be output to the hydraulic cylinder A.

[0052] The torque detection unit 42 monitors the current flowing through the motor 14 to detect the torque output by the motor 14. The motor 14 or the drive circuit of the motor control unit 46 (described later) is provided with a current sensor for driving the motor 14, so the torque detection unit 42 can monitor the current using the current sensor. In the cylinder device 1 of this embodiment, when detecting torque, the controller C drives the motor 14 at a predetermined normal rotation speed RN to drive the pump 13. However, because the first on-off valve 10 and the second on-off valve 12 are open, the hydraulic cylinder A is in an unloaded state in which it does not exert thrust. Therefore, because the hydraulic cylinder A is in an unloaded state, the torque detection unit 42 detects a torque Tm corresponding to the pipeline resistance within the hydraulic cylinder A. Since the torque detection unit 42 detects a torque Tm whose magnitude corresponds to the dynamic viscosity of the hydraulic oil, the lower the temperature of the hydraulic oil, the higher the torque Tm detected.

[0053] As described above, since the torque detection unit 42 monitors the current of the motor 14 while the motor 14 is being driven at the normal rotation speed RN, the torque detection unit 42 can grasp the current flowing through the motor 14 and the rotation speed. Furthermore, since the characteristics of the motor 14 can be grasped in advance, the torque detection unit 42 can detect the torque of the motor 14 from the rotation speed, current, and characteristics of the motor 14 by monitoring the current of the motor 14. Note that the torque detection unit 42 may be a torque sensor that detects the torque of an output shaft (not shown) of the motor 14.

[0054] The average value calculation unit 43 calculates the average value Tma of the torque Tm detected by the torque detection unit 42 over a predetermined time period after the motor 14 is started from a stopped state. Specifically, the average value calculation unit 43 calculates the average value Tma by dividing the sum of the values ​​of the torque Tm detected by the torque detection unit 42 at a predetermined sampling period during the predetermined time period from the start of the motor 14 by the number of samples of the torque Tm. The predetermined time period is, for example, about 5 seconds. The predetermined time period may be determined taking into consideration the processing times of the torque detection unit 42, the selection unit 44, and the rotation speed determination unit 45 so that, while the railway vehicle V is temporarily stopped at a station, the torque detection unit 42 can calculate the average value Tma, the selection unit 44 (described later) can perform a selection process, and the rotation speed determination unit 45 can perform and complete a rotation speed determination process.

[0055] The average value calculation unit 43 may also calculate the artificial average value Tma of the torque Tm by performing low-pass filtering on the torque Tm detected during a predetermined time period after the motor 14 is started from a stopped state.

[0056] The selection unit 44 selects whether to cause the hydraulic cylinder A to function as an actuator or as a passive damper based on the torque Tm detected by the torque detection unit 42. Specifically, the selection unit 44 obtains the speed of the railway vehicle V from a vehicle monitor (not shown) on the railway vehicle V, counts the time since the railway vehicle V stopped, and executes the selection process when the counted time reaches or exceeds a predetermined stopping time. Note that the controller C may be provided with its own sensor that detects the speed of the railway vehicle V, and may detect the speed using the sensor. Note that the stopping time is set to, for example, about 5 seconds, which is a time that allows the train to recognize that it has stopped at a station, a railroad depot, or the like.

[0057] When the selection unit 44 starts the selection process, it inputs a command to execute the selection process to the control command generation unit 50. When the control command generation unit 50 receives an instruction to execute the selection process, it outputs a command to open the first on-off valve 10 to the first on-off valve control unit 48 to open the first on-off valve 10, and outputs a command to open the second on-off valve 12 to the second on-off valve control unit 49 to open the second on-off valve 12 and set the hydraulic cylinder A to an unloaded state, and then outputs a command to start the motor 14 and drive it at a predetermined normal rotation speed RN to the motor control unit 46 to drive the motor 14 at the normal rotation speed RN.

[0058] When the selection process of the selection unit 44 is executed, the torque detection unit 42 detects the torque Tm of the motor 14, and the average value calculation unit 43 calculates the average value Tma of the torque Tm detected from the start of the motor 14 until a predetermined time has elapsed, and inputs the average value Tma to the selection unit 44.

[0059] When the average value Tma of the torque Tm is equal to or greater than the first torque threshold T1, the selection unit 44 selects to have the hydraulic cylinder A function as a passive damper and selects the passive damper mode to have the hydraulic cylinder A function as a passive damper. On the other hand, when the average value Tma of the torque Tm is less than the first torque threshold T1, the selection unit 44 selects to have the hydraulic cylinder A function as an actuator and selects the actuator mode to have the hydraulic cylinder A function as an actuator. The selection unit 44 inputs the selection result, whether the actuator or the passive damper has been selected, to the control command generation unit 50. In the selection process by the selection unit 44, the motor 14 is driven to detect the torque Tm of the motor 14, but because the hydraulic cylinder A is in an unloaded state, the hydraulic cylinder A does not exert thrust to vibrate the carbody B, and therefore the selection process can be performed safely even when the railway vehicle V is in operation.

[0060] The torque Tm of the motor 14 increases in proportion to the kinetic viscosity of the hydraulic oil in the hydraulic cylinder A, so a higher average value Tma indicates a high kinetic viscosity of the hydraulic oil. If the kinetic viscosity of the hydraulic oil becomes too high, driving the motor 14 to make the hydraulic cylinder A function as an actuator will result in excessive pressure loss in the hydraulic cylinder A, causing excessive thrust and leading to a deterioration in the vibration damping of the vehicle body B.

[0061] The first torque threshold T1 is set to the value of the torque Tm of the motor 14 that will be detected when the temperature of the hydraulic oil is low and the kinetic viscosity of the hydraulic oil reaches a value that will deteriorate the vibration-damping performance of the vehicle body B. Therefore, as described above, as a result of comparing the average value Tma with the first torque threshold T1, if the average value Tma is equal to or greater than the first torque threshold T1 and the kinetic viscosity of the hydraulic oil is high, there is a risk of deterioration in the vibration-damping performance of the vehicle body B, and if the average value Tma is less than the first torque threshold T1 and the kinetic viscosity of the hydraulic oil is not so high that causing hydraulic cylinder A to function as an actuator will deteriorate the vibration-damping performance of the vehicle body B, the selection unit 44 selects hydraulic cylinder A to be the actuator.

[0062] Since the torque Tm is the torque detected when the selection process of the selection unit 44 is performed, the selection unit 44 can accurately determine whether the dynamic viscosity is currently excessive by monitoring the dynamic viscosity of the hydraulic oil when the selection process is performed and comparing the average value Tma with the first torque threshold T1.

[0063] Here, when motor 14 is rotated from a stopped state, torque Tm increases when motor 14 starts, and fluctuates until torque Tm of motor 14 stabilizes. Therefore, if torque Tm detected by torque detection unit 42 is used as is in selection unit 44, there is a possibility that the kinetic viscosity of the hydraulic oil cannot be properly determined. In contrast, in the present embodiment, controller C includes average value calculation unit 43, and selection unit 44 selects one of actuator mode and passive damper mode using average value Tma of torque Tm. Therefore, even if torque Tm detected by torque detection unit 42 fluctuates, it is possible to accurately select one of actuator mode and passive damper mode that is appropriate for the kinetic viscosity of the hydraulic oil from among the actuator mode and the passive damper mode.

[0064] It should be noted that, instead of calculating the average value Tma, the selection unit 44 can also perform the selection process using the torque Tm detected after the torque Tm has stabilized several seconds after the start of the motor 14. In contrast, in the cylinder device 1 of the present embodiment, the average value Tma for a predetermined time after the start of the motor 14 is calculated, so that the selection process of the selection unit 44 can be performed with high accuracy even if the torque Tm is not stable. Therefore, the selection process can be completed in a short time compared to when the torque Tm detected after the torque Tm has stabilized is used, and the selection process can be performed in a timely manner within the extremely short time that the railway vehicle V is stopped at a station.

[0065] Next, the rotation speed determination unit 45 receives the selection result of the selection unit 44 as input, and if the selection unit 44 selects the actuator, compares the average value Tma of the torque Tm with the second torque threshold T2 and determines the rotation speed of the motor 14 in accordance with the result of the comparison, and if the selection unit 44 selects the passive damper mode, determines the rotation speed of the motor 14 to be 0.

[0066] When the selection unit 44 selects the passive damper mode, driving the motor 14 causes the hydraulic cylinder A to function as an actuator, so the rotation speed of the motor 14 is set to 0 so that the motor 14 can be stopped and the hydraulic cylinder A can function as a passive damper.

[0067] On the other hand, when the selection unit 44 selects the actuator mode, the rotation speed determination unit 45 determines to set the rotation speed of the motor 14 to a predetermined low rotation speed RL if the value of the average value Tma of the torque Tm is equal to or greater than the second torque threshold T2, and determines to set the rotation speed of the motor 14 to a predetermined normal rotation speed RN if the value of the average value Tma of the torque Tm is less than the second torque threshold T2. The second torque threshold T2 is set to a value lower than the first torque threshold T1, and the selection unit 44 selects the actuator mode when the average value Tma is less than the first torque threshold T1. Therefore, the rotation speed determination unit 45 determines to drive the motor 14 at the low rotation speed RL if T1 > Tma ≥ T2, and determines to drive the motor 14 at the normal rotation speed RN if T2 > Tma. In addition, the rotation speed determination unit 45 may determine to drive the motor 14 at the low rotation speed RL when T1>Tma≧T2 without receiving the selection result from the selection unit 44, and may determine to drive the motor 14 at the normal rotation speed RN when T2>Tma.

[0068] In this way, when the selection unit 44 selects to cause the hydraulic cylinder A to function as an actuator, the rotation speed determination unit 45 sets the rotation speed of the motor 14 to a low rotation speed RL lower than the normal rotation speed RN when the kinetic viscosity of the hydraulic oil is high, resulting in a large pressure loss within the hydraulic cylinder A and a tendency for the thrust to be large. Alternatively, the rotation speed determination unit 45 sets the rotation speed of the motor 14 to a normal rotation speed RN higher than the low rotation speed RL when the kinetic viscosity of the hydraulic oil is low and there is no risk of the thrust of the hydraulic cylinder A being excessive. The normal rotation speed RN is preset to a rotation speed of the motor 14 taking into account the specifications of the hydraulic cylinder A, such that the kinetic viscosity of the hydraulic oil is within a range suitable for normal use and the thrust is appropriate for causing the hydraulic cylinder A to function as an actuator. On the other hand, the low rotation speed RL is set to a rotation speed of the motor 14 such that the thrust of the hydraulic cylinder A is not excessive even when the railway vehicle V is operated in a cold region and the temperature of the hydraulic oil is low and the kinetic viscosity is high. After determining the rotation speed of the motor 14, the rotation speed determination unit 45 inputs the determined rotation speed to the control command generation unit 50.

[0069] In this way, the second torque threshold T2 is a reference torque for selecting a rotation speed of the motor 14 appropriate for the kinetic viscosity of the hydraulic oil. Specifically, even though the temperature of the hydraulic oil is higher and the kinetic viscosity of the hydraulic oil is lower than the kinetic viscosity of the hydraulic oil when the torque Tm is equal to or higher than the first torque threshold T1, driving the motor 14 at the predetermined normal rotation speed RN may result in excessive thrust from the hydraulic cylinder A, impairing the ride comfort of the vehicle body B. Therefore, the second torque threshold T2 is set to the value of the torque Tm of the motor 14 that would be detected when the kinetic viscosity of the hydraulic oil reaches a value at which the thrust from the hydraulic cylinder A becomes excessive when the motor 14 is driven at the predetermined normal rotation speed RN.

[0070] The control command generation unit 50 generates and outputs control commands corresponding to each of the motor control unit 46, the pressure control valve control unit 47, the first opening / closing valve control unit 48 and the second opening / closing valve control unit 49 based on the speed of the railway vehicle V input from a vehicle monitor not shown, the target thrust calculated by the target thrust calculation unit 41, the selection result of the selection unit 44 and the rotation speed of the motor 14 determined by the rotation speed determination unit 45.

[0071] When the speed of the railway vehicle V is less than a predetermined control start speed, the control command generation unit 50 commands each of the motor control unit 46, the pressure control valve control unit 47, the first on-off valve control unit 48, and the second on-off valve control unit 49 to cause the hydraulic cylinder A to function as a passive damper, regardless of the target thrust of the target thrust calculation unit 41 and the selection result of the selection unit 44. In other words, when the speed of the railway vehicle V is less than the control start speed, the control command generation unit 50 generates a motor control command to stop the motor 14, a pressure control valve control command to maximize the valve opening pressure without energizing the pressure control valve 22, and a first on-off valve control command and a second on-off valve control command to close the first on-off valve 10 and the second on-off valve 12, and inputs the corresponding control commands to the motor control unit 46, the pressure control valve control unit 47, the first on-off valve control unit 48, and the second on-off valve control unit 49. The control start speed can be set arbitrarily, but is set to a speed at which the vibration of the railway vehicle V becomes so great that it is required to cause the hydraulic cylinder A to function as an actuator and actively suppress the vibration of the car body B.

[0072] In addition, when the speed of the railway vehicle V reaches or exceeds a predetermined control start speed, the control command generation unit 50 generates each control command to be input to the motor control unit 46, the pressure control valve control unit 47, the first opening / closing valve control unit 48 and the second opening / closing valve control unit 49 according to the selection result of the selection unit 44.

[0073] When the speed of the railway vehicle V is equal to or greater than a predetermined control start speed but the selection unit 44 has selected the passive damper mode, the control command generation unit 50 instructs each of the motor control unit 46, the pressure control valve control unit 47, the first on-off valve control unit 48 and the second on-off valve control unit 49 to stop the motor 14, not energize the pressure control valve 22 to maximize the valve opening pressure, and close the first on-off valve 10 and the second on-off valve 12, in order to make the hydraulic cylinder A function as a passive damper, just as when the speed of the railway vehicle V is less than the predetermined control start speed.

[0074] On the other hand, when the speed of the railway vehicle V is equal to or greater than the predetermined control start speed but the selection unit 44 has selected the actuator mode, the control command generation unit 50 generates a pressure valve control command, a first opening / closing valve control command and a second opening / closing valve control command as instructed by the target thrust calculated by the target thrust calculation unit 41, and gives these to the pressure control valve control unit 47, the first opening / closing valve control unit 48 and the second opening / closing valve control unit 49, and generates a motor control command that instructs the motor 14 to be driven at the rotation speed determined by the rotation speed determination unit 45, and gives this to the motor control unit 46.

[0075] Specifically, the control command generation unit 50 generates a pressure control valve control command that instructs the current to be supplied to the pressure control valve 22 in accordance with the value of the target thrust calculated by the target thrust calculation unit 41, excluding the sign, and inputs the generated pressure control command to the pressure control valve control unit 47. As described above, the magnitude of the thrust of the hydraulic cylinder A can be adjusted by the valve opening pressure of the pressure control valve 22 regardless of the direction of the thrust of the hydraulic cylinder A, so that the valve opening pressure of the pressure control valve 22 for outputting the target thrust to the hydraulic cylinder A can be uniquely calculated from the target thrust. Furthermore, since the valve opening pressure of the pressure control valve 22 can be adjusted by the current supplied to the proportional solenoid 22c of the pressure control valve 22, the control command generation unit 50 calculates the amount of current to be supplied to the proportional solenoid 22c of the pressure control valve 22 from the numerical value of the target thrust calculated by the target thrust calculation unit 41, generates a pressure control valve control command that instructs the amount of current to be supplied to the proportional solenoid 22c, and inputs the generated pressure control valve control command to the pressure control valve control unit 47.

[0076] Furthermore, since the sign of the target thrust value indicates the direction of thrust to be output by hydraulic cylinder A, the control command generation unit 50 generates a first on-off valve control command and a second on-off valve control command for controlling the opening and closing of the first on-off valve 10 and the second on-off valve 12 from the sign. When the sign indicates that hydraulic cylinder A is to generate thrust in the extension direction, the control command generation unit 50 generates a first on-off valve control command to open the first on-off valve 10 and inputs it to the first on-off valve control unit 48, and generates a second on-off valve control command to close the second on-off valve 12 and inputs it to the second on-off valve control unit 49. On the other hand, when the sign indicates that hydraulic cylinder A is to generate thrust in the contraction direction, the control command generation unit 50 generates a first on-off valve control command to close the first on-off valve 10 and inputs it to the first on-off valve control unit 48, and generates a second on-off valve control command to open the second on-off valve 12 and inputs it to the second on-off valve control unit 49.

[0077] Furthermore, the control command generation unit 50 generates a motor control command to drive the motor 14 at the rotation speed determined by the rotation speed determination unit 45 so that the hydraulic cylinder A functions as an actuator, and inputs the motor control command to the motor control unit 46.

[0078] As described above, the control command generation unit 50 causes hydraulic cylinder A to function as a passive damper regardless of the selection result of the selection unit 44 when the speed of the railway vehicle V is below the control start speed, causes hydraulic cylinder A to function as a passive damper when the speed of the railway vehicle V is above the control start speed and the selection result of the selection unit 44 selects the passive damper mode, and causes hydraulic cylinder A to function as an actuator when the speed of the railway vehicle V is above the control start speed and the selection result of the selection unit 44 selects the actuator mode. Furthermore, when causing hydraulic cylinder A to function as an actuator, the control command generation unit 50 drives motor 14 at the rotation speed determined by the rotation speed determination unit 45.

[0079] As described above, when the control command generation unit 50 receives an input of a command from the selection unit 44 instructing the start of the selection process, it outputs a first on-off valve control command to open the first on-off valve 10 to the first on-off valve control unit 48 to open the first on-off valve 10, and outputs a second on-off valve control command to open the second on-off valve 12 to the second on-off valve control unit 49 to open the second on-off valve 12, while outputting a motor control command to the motor control unit 46 to start the motor 14 and drive it at the normal rotation speed RN, thereby driving the motor 14 at the normal rotation speed RN.

[0080] Next, the motor control unit 46 drives the motor 14 at the rotation speed instructed by the motor control command input from the control command generation unit 50. Although not shown, the motor control unit 46 is a motor driver that has a drive circuit that supplies current to the motor 14, monitors the current flowing through the motor 14 and the rotation speed, and controls the drive circuit to control the motor 14 to the rotation speed instructed by the rotation speed determination unit 45.

[0081] The motor control unit 46 detects the current and rotation speed of the motor 14 and performs feedback control.When the control command generation unit 50 instructs the motor 14 to stop, the motor control unit 46 stops the motor 14 without supplying current to the motor 14.When the rotation speed instructed by the control command generation unit 50 is the normal rotation speed RN, the motor control unit 46 supplies current to the motor 14 so that the rotation speed of the motor 14 matches the normal rotation speed RN.When the rotation speed instructed by the control command generation unit 50 is the low rotation speed RL, the motor control unit 46 supplies current to the motor 14 so that the rotation speed of the motor 14 matches the low rotation speed RL.

[0082] Note that when the speed of the railway vehicle V falls below a predetermined control start speed, the control command generation unit 50 instructs the motor 14 to stop, and therefore the motor control unit 46 stops the motor 14 and does not drive the motor 14. Furthermore, when the selection process of the selection unit 44 is performed, the condition for the selection process by the selection unit 44 is that the railway vehicle V is stopped, and when the speed of the railway vehicle V is below the control start speed, the control command generation unit 50 inputs a motor control command to the motor control unit 46 that instructs the motor 14 to stop. Therefore, when the selection process is performed, the motor control unit 46 always starts the motor 14 that is in a stopped state.

[0083] The pressure control valve control unit 47 supplies a current instructed by a pressure control valve control command input from the control command generation unit 50 to the proportional solenoid 22c of the pressure control valve 22 to adjust the valve opening pressure of the pressure control valve 22. Although not shown, the pressure control valve control unit 47 is a solenoid driver that has a drive circuit that supplies a current to the proportional solenoid 22c, monitors the current flowing through the proportional solenoid 22c, and PWM-controls the drive circuit to control the amount of current flowing through the proportional solenoid 22c to the amount of current instructed by the control command generation unit 50.

[0084] The first on-off valve control unit 48 opens and closes the first on-off valve 10 as instructed by a first on-off valve control command input from the control command generation unit 50. When the first on-off valve control command instructs to close the first on-off valve 10, the first on-off valve control unit 48 does not energize the solenoid 10e of the first on-off valve 10, causing the first on-off valve 10 to be in the shut-off position 10c. On the other hand, when the first on-off valve control command instructs to open the first on-off valve 10, the first on-off valve control unit 48 energizes the solenoid 10e of the first on-off valve 10 to excite the solenoid 10e, causing the first on-off valve 10 to be in the communicating position 10b. Although not shown, the first on-off valve control unit 48 has a drive circuit equipped with a switch and serves as a solenoid driver that switches between energizing and de-energizing the solenoid 10e by switching the switch on and off.

[0085] Similarly to the first on-off valve control unit 48, the second on-off valve control unit 49 also opens and closes the second on-off valve 12 as instructed by a second on-off valve control command input from the control command generation unit 50. When the second on-off valve control command instructs the second on-off valve 12 to be closed, the second on-off valve control unit 49 does not energize the solenoid 12e of the second on-off valve 12, causing the second on-off valve 12 to be in the shut-off position 12c. On the other hand, when the second on-off valve control command instructs the second on-off valve 12 to be open, the second on-off valve control unit 49 energizes the solenoid 12e of the second on-off valve 12 to excite the solenoid 12e, causing the second on-off valve 12 to be in the communicating position 12b. Although not shown, the second on-off valve control unit 49 has a drive circuit equipped with a switch not shown, and serves as a solenoid driver that switches between energizing and de-energizing the solenoid 12e by switching the switch on and off.

[0086] Although not shown in the figure, the controller C may be configured with, as hardware resources, specifically, for example, a CPU (Central Processing Unit) that executes an operating system and other programs for controlling the motor 14, the first on-off valve 10, the second on-off valve 12, and the pressure control valve 22, a storage device such as a ROM (Read Only Memory) that stores the programs necessary for the control, a storage device such as a RAM (Random Access Memory) that provides storage space for the CPU, and an interface for exchanging signals between the CPU, acceleration sensor 40, motor control unit 46, pressure control valve control unit 47, first on-off valve control unit 48, and second on-off valve control unit 49.

[0087] The target thrust calculation unit 41, torque detection unit 42, average value calculation unit 43, selection unit 44, rotation speed determination unit 45 and control command generation unit 50 in the controller C are realized by the CPU executing a program that performs the above control.

[0088] First, the selection process of the controller C for selecting whether to make the hydraulic cylinder A function as a passive damper or as an actuator will be described with reference to the flowchart shown in FIG.

[0089] In the selection process, in order to determine whether the conditions for executing the selection process are met, the controller C determines whether the stopping time of the railway vehicle V after the speed of the railway vehicle V has decreased and the railway vehicle V has stopped is equal to or longer than a predetermined stopping time (step S1). At the time of determining whether the stopping time is equal to or longer than the predetermined stopping time, the railway vehicle V has already stopped, and therefore, as described above, the hydraulic cylinder A is not controlled as an actuator but is made to function as a passive damper, so the motor 14 is stopped and the first on-off valve 10 and the second on-off valve 12 are both closed.

[0090] If it is determined in step S1 that the time that the railway vehicle V has been stopped is less than the predetermined stopping time, the time is counted and the determination in step S1 is repeated. On the other hand, if it is determined in step S1 that the time that the railway vehicle V has been stopped is equal to or longer than the predetermined stopping time, the conditions for executing a selection process to select one of the actuator mode and the passive damper mode are met, and so the controller C opens the first on-off valve 10 and the second on-off valve 12 to execute the selection process, and then drives the motor 14 at the normal rotation speed RN to supply hydraulic oil from the pump 13 into the cylinder 3 (step S2). With the first on-off valve 10 and the second on-off valve 12 open, the rod-side chamber 6 and the piston-side chamber 7 are connected to the tank 8 via the first passage 9 and the second passage 11, and even if the pump 13 is driven, hydraulic oil is returned to the tank 8 via the cylinder 3, so that the hydraulic cylinder A is in an unloaded state and does not generate thrust.

[0091] Next, the controller C reads the torque Tm of the motor 14 measured during a predetermined time period from when the motor 14 is started, and calculates an average value Tma of the torque Tm (step S3). Then, the controller C determines whether the average value Tma is equal to or greater than a first torque threshold T1 in order to select whether the hydraulic cylinder A functions as an actuator or as a passive damper (step S4).

[0092] If the determination in step S4 is that the average value Tma is equal to or greater than the first torque threshold T1, the dynamic viscosity of the hydraulic oil is high and is not suitable for causing the hydraulic cylinder A to function as an actuator, so the passive damper mode in which the hydraulic cylinder A functions as a passive damper is selected (step S5). Then, the controller C stops driving the motor 14, and then closes the first on-off valve 10 and the second on-off valve 12 (step S6), ending the process.

[0093] Furthermore, if the determination in step S4 shows that the average value Tma is less than the first torque threshold T1, the kinetic viscosity of the hydraulic oil is low and the hydraulic cylinder A can function as an actuator, so the controller C selects the actuator mode and proceeds to step S7, where it determines whether the average value Tma is less than the first torque threshold T1 and greater than or equal to the second torque threshold T2 in order to determine whether the kinetic viscosity of the hydraulic oil is suitable for setting the rotation speed of the motor 14 to the normal rotation speed RN or the low rotation speed RL. Note that, in the determination in step S7, since the average value Tma is less than the first torque threshold T1 in the determination in step S4, it is sufficient to determine whether the average value Tma is greater than or equal to the second torque threshold T1.

[0094] If it is determined in step S7 that the average value Tma is less than the first torque threshold value T1 and greater than or equal to the second torque threshold value T2, the dynamic viscosity of the hydraulic oil is high enough to allow the hydraulic cylinder A to function as an actuator, and the thrust of the hydraulic cylinder A tends to increase when the motor 14 is driven at the normal rotation speed RN. Therefore, the controller C determines to adopt the low rotation speed RL and sets the rotation speed of the motor 14 to the low rotation speed RL (step S8).

[0095] After setting the rotation speed of the motor 14 in step S8, the controller C proceeds to step S6, stops driving the motor 14, and closes the first on-off valve 10 and the second on-off valve 12.

[0096] Furthermore, if it is determined in step S7 that the average value Tma is less than the second torque threshold value T2, the dynamic viscosity of the hydraulic oil is low enough to enable the hydraulic cylinder A to function as an actuator and to drive the motor 14 at the normal rotation speed RN, so the controller C decides to adopt the normal rotation speed RN and sets the rotation speed of the motor 14 to the normal rotation speed RN (step S9). After setting the rotation speed of the motor 14 in step S9, the controller C proceeds to step S6, stops driving the motor 14, and closes the first on-off valve 10 and the second on-off valve 12.

[0097] In this way, each time the railway vehicle V stops, when the time that the railway vehicle V has been stopped reaches or exceeds a predetermined stop time, the controller C executes a selection process to select either an actuator mode in which the hydraulic cylinder A functions as an actuator, or a passive damper mode in which the hydraulic cylinder A functions as a passive damper. Therefore, depending on the temperature of the region in which the railway vehicle V travels, either the actuator or the passive damper, whichever is more suitable for suppressing vibration of the carbody B, can be selected to cause the hydraulic cylinder A to function. Furthermore, because the selection process is executed while the railway vehicle V is stopped, even if the line on which the railway vehicle V travels is established in both warm and cold regions, each time the railway vehicle V stops, either the actuator or the passive damper, whichever is more suitable, is selected in accordance with changes in the kinematic viscosity of the hydraulic oil, so that vibration of the carbody B can be effectively suppressed in accordance with the temperature of the region in which the railway vehicle V travels.

[0098] Next, the control of the hydraulic cylinder A by the controller C while the railway vehicle V is traveling will be described with reference to the flowchart shown in FIG.

[0099] If the speed of the railway vehicle V while it is traveling is less than the control start speed, the hydraulic cylinder A does not function as an actuator, but if the speed of the railway vehicle V becomes equal to or greater than the control start speed, the hydraulic cylinder A can function as an actuator. Therefore, the controller C determines whether the speed of the railway vehicle V input from a vehicle monitor not shown is equal to or greater than the control start speed (step S11).

[0100] If it is determined in step S11 that the speed of the railway vehicle V is less than the control start speed, the controller C stops the motor 14, closes the first opening / closing valve 10 and the second opening / closing valve 12, and does not energize the pressure control valve 22, setting the valve opening pressure to its maximum, causing the hydraulic cylinder A to function as a passive damper (step S12).

[0101] On the other hand, if it is determined in step S11 that the speed of the railway vehicle V is equal to or greater than the control start speed, the controller C determines whether the actuator mode is selected (step S13), and if the actuator mode is selected, calculates a target thrust to cause the hydraulic cylinder A to function as an actuator (step S14).

[0102] Then, the process proceeds to step S15, where the controller C drives the motor 14 at the rotation speed determined in conjunction with the selection process, while adjusting the valve opening pressure of the pressure control valve 22 and switching the first opening / closing valve 10 and the second opening / closing valve 12 on and off so that the hydraulic cylinder A outputs the thrust indicated by the target thrust.

[0103] On the other hand, if it is determined in step S11 that the actuator mode has not been selected but the passive damper mode has been selected, the controller C proceeds to step S16, stops the motor 14, closes the first on-off valve 10 and the second on-off valve 12, does not energize the pressure control valve 22 to maximize the valve opening pressure, and causes the hydraulic cylinder A to function as a passive damper.

[0104] This control by the controller C while the railway vehicle V is traveling is repeatedly executed while the railway vehicle V is traveling, and when the speed of the railway vehicle V is equal to or greater than the control start speed, if the actuator mode is selected by the selection process, the hydraulic cylinder A functions as an actuator to output the target thrust determined by the controller C, and when the passive damper mode is selected by the selection process even if the speed of the railway vehicle V is equal to or greater than the control start speed, or when the speed of the railway vehicle V is less than the control start speed, the hydraulic cylinder A functions as a passive damper. Then, when the railway vehicle V stops, the selection process is executed by the controller C to select either the actuator mode or the passive damper mode.

[0105] As described above, the cylinder device 1 of this embodiment has a cylinder body 2 that expands and contracts when hydraulic oil (hydraulic liquid) is supplied, a pump 13 that supplies hydraulic oil (hydraulic liquid) to the cylinder body 2, and a motor 14 that drives the pump 13, and is equipped with a hydraulic cylinder A that can function as an actuator when driven by the pump 13 and can also function as a passive damper when the pump 13 is stopped, and a controller C that controls the motor 14, and the controller C is equipped with a torque detection unit 42 that detects the torque Tm of the motor 14, and a selection unit 44 that selects either an actuator mode in which the hydraulic cylinder A functions as an actuator or a passive damper mode in which the hydraulic cylinder A functions as a passive damper based on the torque Tm detected by the torque detection unit 42.

[0106] According to the cylinder device 1 configured in this manner, either the actuator mode or the passive damper mode is selected based on the torque Tm of the motor 14, which changes depending on the kinetic viscosity of the hydraulic oil (working liquid) in the hydraulic cylinder A. Therefore, it is possible to accurately determine whether the actuator mode or the passive damper mode is suitable for the current kinetic viscosity of the hydraulic oil (working liquid), and to generate an appropriate thrust in response to changes in the kinetic viscosity of the hydraulic oil (working liquid).

[0107] Therefore, according to the cylinder device 1 of this embodiment, vibration of the car body B of the railway vehicle V can be efficiently suppressed even when the outside air temperature changes, and the dynamic viscosity of the hydraulic oil (working liquid) can be accurately grasped.Therefore, compared to conventional cylinder devices that estimate the temperature of the hydraulic oil (working liquid) using date or location information or directly detect the temperature of the hydraulic oil (working liquid), control can be performed that is appropriate for the dynamic viscosity of the actual hydraulic oil (working liquid), and the ride comfort of the railway vehicle V can be improved.

[0108] Furthermore, in the cylinder device 1 of the present embodiment, the controller C includes a rotation speed determination unit 45 that determines the rotation speed of the motor 14 based on the torque Tm.

[0109] According to the cylinder device 1 configured in this manner, when the hydraulic cylinder A is made to function as an actuator, the motor 14 can be driven at a rotation speed suited to the dynamic viscosity of the hydraulic oil, thereby preventing excessive thrust from being output by the hydraulic cylinder A. Furthermore, according to the cylinder device 1 of this embodiment, by using the hydraulic cylinder A in a railway vehicle V, the thrust of the hydraulic cylinder A functioning as an actuator can be prevented from becoming higher than the target thrust, thereby improving the ride comfort in the vehicle even when the temperature changes.

[0110] Furthermore, according to the cylinder device 1 of this embodiment, even when feedback control is performed on the thrust of hydraulic cylinder A, excessive thrust does not occur even if the dynamic viscosity of the hydraulic oil (working liquid) is high, so the error between the target thrust and the thrust actually output is reduced, hunting, which causes the thrust of hydraulic cylinder A to become oscillatory, is also reduced, and the problem of vibrating the body B of the railway vehicle and worsening the vibration situation does not occur.

[0111] Furthermore, in the cylinder device 1 of this embodiment, when the torque Tm is equal to or greater than a first torque threshold T1, the controller C causes the hydraulic cylinder A to function as a passive damper, and when the torque Tm is less than the first torque threshold T1 and equal to or greater than a second torque threshold T2 that is lower than the first torque threshold T1, the controller C drives the motor 14 at a low rotation speed RL to cause the hydraulic cylinder A to function as an actuator, and when the torque Tm is less than the second torque threshold T2, the controller C drives the motor 14 at a normal rotation speed RN that is higher than the low rotation speed R1 to cause the hydraulic cylinder A to function as an actuator.

[0112] According to the cylinder device 1 configured in this manner, by setting a first torque threshold T1 and a second torque threshold T2 for the torque Tm and comparing the torque Tm with these first torque threshold T1 and second torque threshold T2, it is possible to easily switch between the actuator mode and the passive damper mode and switch the rotation speed of the motor 14, thereby generating an appropriate thrust according to the dynamic viscosity of the hydraulic oil (working liquid).

[0113] Furthermore, in the cylinder device 1 of this embodiment, the controller C has an average value calculation unit 43 that calculates the average value Tma of the torque Tm detected over a predetermined time period after the motor 14 is started from a stopped state, and the selection unit 44 selects one of the actuator mode and the passive damper mode based on the average value Tma of the torque Tm.

[0114] According to the cylinder device 1 configured in this manner, the selection unit 44 selects either the actuator mode or the passive damper mode using the average value Tma of the torque Tm, so that even if the torque Tm detected by the torque detection unit 42 fluctuates, it is possible to accurately select whether the actuator or the passive damper is suitable for the dynamic viscosity of the hydraulic oil, and the selection process can be completed in a short time. Therefore, when the cylinder device 1 is used in a railway vehicle V, the selection process can be performed even during an extremely short stop at a station, and the selection process can be performed in a timely manner each time the train stops at a station, allowing the hydraulic cylinder A to function as either the actuator or the passive damper that is suitable for the dynamic viscosity of the hydraulic oil (working liquid), thereby improving the ride comfort of the vehicle.

[0115] Furthermore, in the cylinder device 1 of this embodiment, the hydraulic cylinder A is interposed between the bogie T and the carbody B of the railway vehicle V, and the selection unit 44 selects one of the actuator mode and the passive damper mode when the railway vehicle V remains stopped for a predetermined stopping time. In the cylinder device 1 configured in this manner, the selection unit 44 executes the selection process when the railway vehicle V remains stopped for a predetermined stopping time, so the selection process can be executed when the railway vehicle V stops at a station or the like, and the selection process is performed in a timely manner to allow the hydraulic cylinder A to function as one of the actuator and passive damper modes that is suited to the kinetic viscosity of the hydraulic oil (working liquid), thereby improving the ride comfort of the vehicle.

[0116] In the above description, the cylinder device 1 is applied to a railway vehicle V, but the cylinder device 1 may also be used in various equipment other than the railway vehicle V, such as construction machinery, ships, and aircraft.

[0117] Although the description of the embodiment of the present invention has been completed above, it goes without saying that the scope of the present invention is not limited to the exact details shown or described. [Explanation of symbols]

[0118] 1···Cylinder device, 2···Cylinder body, 13···Pump, 14···Motor, 42···Torque detection unit, 43···Average value calculation unit, 44···Selection unit, 45···Rotation speed determination unit, A···Hydraulic cylinder, B···Car body, C···Controller, T···Bogie, V···Railway vehicle

Claims

1. a hydraulic cylinder having a cylinder body that expands and contracts when hydraulic fluid is supplied to the cylinder body, a pump that supplies the hydraulic fluid to the cylinder body, and a motor that drives the pump, and which can function as an actuator when the pump is driven and can also function as a passive damper when the pump is stopped; a controller for controlling the motor; The controller a torque detection unit that detects the torque of the motor; a selection unit that selects either an actuator mode in which the hydraulic cylinder functions as an actuator or a passive damper mode in which the hydraulic cylinder functions as a passive damper based on the torque detected by the torque detection unit. A cylinder device characterized by:

2. The controller has a rotation speed determination unit that determines the rotation speed of the motor based on the torque.

2. The cylinder device according to claim 1.

3. The controller causing the hydraulic cylinder to function as a passive damper when the torque is equal to or greater than a first torque threshold; When the torque is less than the first torque threshold and is equal to or greater than a second torque threshold that is lower than the first torque threshold, driving the motor at a low rotation speed to cause the hydraulic cylinder to function as an actuator; If the torque is less than the second torque threshold, the motor is driven at a normal rotation speed that is higher than the low rotation speed, causing the hydraulic cylinder to function as an actuator.

2. The cylinder device according to claim 1.

4. The controller an average value calculation unit that calculates an average value of torque detected over a predetermined time period after the motor is started from a stopped state; The selection unit Selecting one of the actuator mode and the passive damper mode based on the average value of the torque.

4. The cylinder device according to claim 1, wherein the cylinder device is a cylinder body.

5. The hydraulic cylinder is interposed between a bogie and a car body of a railway vehicle, The selection unit selects one of the actuator mode and the passive damper mode when the stopped state of the railway vehicle continues for a predetermined stopping time.

2. The cylinder device according to claim 1.

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