CN121111917A

CN121111917A - Cylinder device

Info

Publication number: CN121111917A
Application number: CN202510640811.6A
Authority: CN
Inventors: 小川贵之
Original assignee: KYB Corp
Current assignee: KYB Corp
Priority date: 2024-06-10
Filing date: 2025-05-19
Publication date: 2025-12-12
Also published as: JP2025185587A

Abstract

The cylinder device 1 includes: a hydraulic cylinder A, a cylinder body 2 that extends and retracts due to the supply of working fluid, a pump 13 that supplies working fluid to the cylinder body 2, and a motor 14 that drives the pump 13, which can function as an actuator by being driven by the pump 13 and can function as a passive damper when the pump 13 stops; and a controller C that controls the motor 14; the controller C includes: a torque detection unit 42 that detects the torque Tm of the motor 14; and a selection unit 44 that, based on the torque Tm detected by the torque detection unit 42, selects either an actuator mode that functions as an actuator or a passive damper mode that functions as a passive damper.

Description

Cylinder device

Technical Field

The invention relates to an improvement of a cylinder device.

Background

Conventionally, such a cylinder device is used for various machines, vehicles, and the like, and is used between a vehicle body and a bogie in order to suppress vibrations in the lateral direction with respect to the forward direction of the vehicle body in a railway vehicle, for example.

More specifically, the cylinder device includes a hydraulic cylinder having a cylinder connected to one of a bogie and a vehicle body of a railway vehicle, a piston slidably inserted into the cylinder, a rod inserted into the cylinder and connected to the other of the bogie and the vehicle body, a rod side chamber and a piston side chamber partitioned by the piston in the cylinder, a reservoir tank, a first switching valve provided in the middle of a first passage communicating the rod side chamber and the piston side chamber, a second switching valve provided in the middle of a second passage communicating the piston side chamber and the reservoir tank, a pump for supplying hydraulic oil to the rod side chamber, a discharge passage connecting the rod side chamber to the reservoir tank, a variable relief valve provided in the middle of the discharge passage and capable of changing a valve opening pressure, and a motor for driving the pump, and a controller for controlling the motor and each valve, and for generating thrust by supplying hydraulic oil into the cylinder by driving the pump.

In such a cylinder device, when functioning as an actuator, a pump is driven at a constant rotational speed, and hydraulic oil is supplied into the cylinder, whereby the valve opening pressure of the variable relief valve is adjusted to generate a desired thrust force. However, when a railway vehicle is used on a route in a cold region, since the hydraulic oil in the hydraulic cylinder is extremely low in temperature and the kinematic viscosity of the hydraulic oil is high, if the rotation speed of the pump is set to be constant, the pressure loss becomes large due to the variable relief valve, the line resistance, or the like, the pressure in the cylinder becomes excessively high, the thrust force becomes excessive, and the riding comfort of the vehicle becomes poor.

In contrast, in the conventional cylinder device, as disclosed in JP2013-1305A, the temperature of the hydraulic oil is estimated based on date and position information, and when 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 force of the cylinder device from becoming excessive.

Problems to be solved by the invention

In the conventional cylinder device, in order to suppress the thrust force surplus by changing the rotational speed of the pump according to the temperature of the hydraulic oil, the temperature of the hydraulic oil is estimated based on the date or position information, or the oil temperature is detected, but the actual kinematic viscosity of the hydraulic oil cannot be grasped, and therefore, there is a possibility that the proper thrust force cannot be exerted in response to the change in the actual kinematic viscosity of the hydraulic oil, and the riding comfort of the vehicle may be improved.

In the conventional cylinder device, there is a problem that it is difficult to exert an appropriate thrust force in response to a change in the kinematic viscosity of the working fluid in the cylinder device, and even when the cylinder device is used in an apparatus other than a railway vehicle, which requires vibration suppression, the same problem occurs when the apparatus is used in a cold region.

In view of the above, an object of the present invention is to provide a cylinder device capable of generating an appropriate thrust force in response to a change in the kinematic viscosity of a working fluid in the cylinder device.

Technical means for solving the problems

In order to achieve the above object, a cylinder device according to the present invention includes a hydraulic cylinder having a cylinder body that expands and contracts by supply of a working fluid, a pump that supplies the working fluid to the cylinder body, and a motor that drives the pump, the hydraulic cylinder being capable of functioning as an actuator by driving the pump and functioning as a passive damper when the pump is stopped, and a controller that controls the motor, the controller including a torque detection unit that detects a torque of the motor, and a selection unit that selects either one of an actuator mode that causes the hydraulic cylinder to function as the actuator or a passive damper mode that functions as the passive damper based on the torque detected by the torque detection unit.

According to the cylinder device configured in this way, since one of the actuator mode and the passive mode is selected based on the torque of the motor that varies according to the kinematic viscosity of the working fluid of the hydraulic cylinder, it is possible to determine with high accuracy which of the actuator mode and the passive damper mode is suitable for the kinematic viscosity of the current working fluid, and it is possible to generate an appropriate thrust force in accordance with the variation in the kinematic viscosity of the working fluid.

Drawings

Fig. 1 is a diagram showing a cylinder device provided in an embodiment of a railway vehicle.

Fig. 2 is a circuit diagram of an actuator in a cylinder device of an embodiment.

Fig. 3 is a structural diagram of a controller in the cylinder device according to the embodiment.

Fig. 4 is a flowchart showing a sequence of selection processing of the controller in the cylinder device according to the embodiment.

Fig. 5 is a flowchart showing a sequence of control processing of the hydraulic cylinder of the controller in the cylinder device according to the embodiment.

Description of the embodiments

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

Specifically, one end of the hydraulic cylinder a is connected to the bogie T, and the other end is connected to a pin P suspended below the vehicle body B, and the hydraulic cylinder a is interposed between the bogie T and the vehicle body B in the railway vehicle V, and suppresses vibration of the vehicle body B by the thrust exerted. The cylinder device 1 may be used for equipment other than railway vehicles, which requires vibration suppression, and the like.

Hereinafter, each part of the cylinder device 1 will be described in detail. First, the hydraulic cylinder a will be described. The hydraulic cylinder a includes a cylinder body 2 that expands and contracts due to supply of the working fluid, a pump 13 that supplies the working fluid to the cylinder body 2, and a motor 14 that drives the pump 13, and can function as an actuator by driving the pump 13 and also as a passive damper when the pump 13 is stopped.

Specifically, as shown in fig. 2, the hydraulic cylinder a 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, rod-side chambers 6 and 7 defined by the piston 4 in the cylinder 3, a liquid reservoir 8, a first on-off valve 10 provided in the middle of a first passage 9 communicating the rod-side chambers 6 and 7, a second on-off valve 12 provided in the middle of a second passage 11 communicating the piston-side chambers 7 and 8, a pump 13 for supplying liquid to the rod-side chambers 6 in the cylinder 3, a motor 14 for driving the pump 13, a discharge passage 21 communicating the rod-side chambers 6 and 8, and a pressure control valve 22 provided in the discharge passage 21 and adjusting the pressure in the cylinder 3. The rod-side chamber 6 and the piston-side chamber 7 are filled with hydraulic oil as a working fluid, and the reservoir tank 8 is filled with gas in addition to the hydraulic oil. The hydraulic fluid used in the hydraulic cylinder a of the present embodiment is hydraulic oil, but the hydraulic fluid may be an antifreeze other than hydraulic oil.

The hydraulic cylinder a generates a thrust in the expansion direction when the first passage 9 is placed in a communication state by the first switching valve 10 and the pump 13 is driven in a state where the second switching valve 12 is closed, and generates a thrust in the contraction direction when the second passage 11 is placed in a communication state by the second switching valve 12 and the pump 13 is driven in a state where the first switching valve 10 is closed.

Hereinafter, each part of the hydraulic cylinder a will be described in detail. The cylinder 3 has a cylindrical shape, the right end of which is closed by a cover 15 in fig. 2, and the left end of which is fitted with an annular guide 16 in fig. 2. The rod 5 inserted into the cylinder 3 so as to be movable is inserted into the guide 16 so as to be slidable. One end of the rod 5 protrudes outside the cylinder 3, and the other end in the cylinder 3 is connected to a piston 4 that is also slidably inserted into the cylinder 3.

The space between the outer periphery of the rod 5 and the cylinder 3 is sealed by a sealing member, not shown, so that the inside of the cylinder 3 is maintained in a sealed state. The rod-side chamber 6 and the piston-side chamber 7 defined by the piston 4 in the cylinder 3 are filled with hydraulic oil as a liquid as described above. Although not shown in detail, the hydraulic cylinder a includes an outer tube 23, the outer tube 23 is tubular and covers the outer periphery of the cylinder 3, the open ends of both ends are closed by a cover 15 and a guide 16, respectively, a liquid reservoir 8 is formed between the cylinder 3 and the liquid reservoir 8, and the liquid reservoir 8 is integrally provided with the cylinder body 2. Further, the liquid reservoir 8 is filled with hydraulic oil as a liquid and filled with gas.

The cover 15 closing the left end of the rod 5 and the right end of the cylinder 3 in fig. 2 includes an unillustrated attachment portion, and the rod 5 of the hydraulic cylinder a can be coupled to the bogie T in the railway vehicle V, the cylinder 3 can be coupled to the vehicle body B, and the hydraulic cylinder a can be interposed between the bogie T and the vehicle body B by the attachment portion outside the drawing.

The rod-side chamber 6 and the piston-side chamber 7 are communicated with each other through a first passage 9, and a first on-off valve 10 is provided in the middle of the first passage 9. The first passage 9 communicates with the rod side chamber 6 and the piston side chamber 7 outside the cylinder 3, but may be provided in the piston 4.

In this embodiment, the first switching valve 10 is an electromagnetic switching valve, and includes a valve body 10a having a communication position 10b for opening the first passage 9 to communicate the rod side chamber 6 with the piston side chamber 7 and a blocking position 10c for blocking communication between the rod side chamber 6 and the piston side chamber 7, a spring 10d for biasing the valve body 10a to adopt the blocking position 10c, and a solenoid 10e for switching the valve body 10a to the communication position 10b against the spring 10d when energized.

Next, the piston-side chamber 7 and the reservoir tank 8 communicate through a second passage 11, and a second on-off valve 12 is provided in the middle of the second passage 11. In this embodiment, the second switching valve 12 is an electromagnetic switching valve, and includes a valve body 12a having a communication position 12b for opening the second passage 11 to communicate the piston side chamber 7 with the reservoir tank 8 and a blocking position 12c for blocking communication between the piston side chamber 7 and the reservoir tank 8, a spring 12d for biasing the valve body 12a to adopt the blocking position 12c, and a solenoid 12e for switching the valve body 12a to the communication position 12b against the spring 12d when energized.

The pump 13 is driven by a motor 14. The pump 13 is a pump that ejects liquid in only one direction, and its ejection port communicates with the rod-side chamber 6 through the supply passage 17, and its suction port communicates with the liquid reservoir 8, and when driven by the motor 14, sucks liquid from the liquid reservoir 8 and supplies the liquid to the rod-side chamber 6.

As described above, since the pump 13 ejects the liquid in only one direction and there is no switching operation of the rotation direction, there is no problem that the ejection amount changes at the time of the rotation switching, and an inexpensive gear pump or the like can be used. Further, since the rotation direction of the pump 13 is always the same direction, even the motor 14 as the driving source for driving the pump 13 does not require high responsiveness to rotation switching, and accordingly, an inexpensive motor 14 can be used. Further, a check valve 18 for preventing the liquid from flowing backward from the rod-side chamber 6 to the pump 13 is provided in the middle of the supply passage 17.

In the case of this embodiment, the rod-side chamber 6 and the reservoir tank 8 are connected by a discharge passage 21, and a pressure control valve 22 capable of changing the valve opening pressure is provided in the middle of the discharge passage 21.

The pressure control valve 22 includes a valve body 22a provided in the middle of the discharge passage 21, a spring 22b that biases the valve body 22a so as to intercept the discharge passage 21, and a proportional solenoid 22c that generates a thrust force against the spring 22b when energized, and is configured as a variable relief valve that biases the valve body 22a in a valve opening direction by an upstream-side pressure, and can adjust a valve opening pressure by adjusting an amount of current flowing to the proportional solenoid 22 c. The pressure control valve 22 may be a valve other than a variable relief valve as long as the pressure on the upstream side can be adjusted.

In the pressure control valve 22, if the pressure of the rod-side chamber 6 in the cylinder 3 acting upstream of the valve body 22a as the discharge passage 21 exceeds the relief pressure (valve opening pressure), the resultant of the force applied in the valve opening direction of the valve body 22a due to the pressure of the rod-side chamber 6 and the force of the proportional solenoid 22c pushing the valve body 22a exceeds the force of the spring 22b applying the valve body 22a, and the valve body 22a opens the discharge passage 21.

Further, by adjusting the amount of current supplied to the proportional solenoid 22c, the thrust force applied to the valve body 22a by the proportional solenoid 22c can be adjusted, and the pressure control valve 22 sets the valve opening pressure to be minimum when the amount of current supplied to the proportional solenoid 22c is maximized, and conversely, sets the valve opening pressure to be maximum when no current is supplied to the proportional solenoid 22c at all.

The pressure control valve 22 opens and communicates the rod side chamber 6 and the tank 8 through the discharge passage 21 when there is an excessive input in the expansion and contraction direction of the hydraulic cylinder a and the pressure in the rod side chamber 6 exceeds the valve opening pressure, regardless of the open/close states of the first and second open/close valves 10 and 12, and thus serves to prevent the excessive pressure in the rod side chamber 6 and protect the entire system of the hydraulic cylinder a.

The hydraulic cylinder a in the cylinder device 1 of the present embodiment includes a rectifying passage 19 that communicates with the piston side chamber 7 and the rod side chamber 6, and a suction passage 20 that communicates with the reservoir tank 8 and the piston side chamber 7.

The rectifying passage 19 is provided with a check valve 19a midway, and is set as a passage allowing only one-way passage of the liquid from the piston-side chamber 7 to the rod-side chamber 6. The suction passage 20 is provided with a check valve 20a in the middle, and is set to a passage allowing only one-way passage of the liquid from the reservoir 8 to the piston-side chamber 7. The rectifying passage 19 may be collected in the first passage 9 by using the cutoff position 10c of the first switching valve 10 as a check valve, and the suction passage 20 may be collected in the second passage 11 by using the cutoff position 12c of the second switching valve 12 as a check valve.

When the hydraulic cylinder a configured in this way is caused to exert a thrust in the desired extension direction, the first switching valve 10 is set to the communication position 10b, the second switching valve 12 is set to the blocking position 12c, the motor 14 is rotated at a constant speed, and the liquid is supplied from the pump 13 into the cylinder 3. In this way, the rod side chamber 6 and the piston side chamber 7 are in communication, liquid is supplied from the pump 13 to the rod side chamber 6 and the piston side chamber 7, the piston 4 is pushed to the left in fig. 2, and the hydraulic cylinder a exerts thrust in the extension direction. When the pressures of the rod side chamber 6 and the piston side chamber 7 in the cylinder 3 exceed the valve opening pressure of the pressure control valve 22, the pressure control valve 22 opens and the liquid in the cylinder 3 moves to the liquid reservoir 8 through 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. Further, the hydraulic cylinder a generates a thrust force that pushes the piston 4 to the left in fig. 2 because the pressure receiving area of the piston 4 on the piston side chamber side facing the piston side chamber 7 is larger than the pressure receiving area of the piston 4 on the rod side chamber side facing the rod side chamber 6 by only the cross-sectional area of the rod 5. In this way, the hydraulic cylinder a can generate a thrust force that drives the pump 13 to extend the cylinder body 2, the thrust force being equal to a value obtained by multiplying the cross-sectional area of the rod 5 by the valve opening pressure of the pressure control valve 22. Therefore, by adjusting the valve opening pressure of the pressure control valve 22, the thrust force in the extension direction generated by the hydraulic cylinder a can be adjusted.

In contrast, when the hydraulic cylinder a is caused to generate a thrust in the required contraction direction, the first switching valve 10 is set to the blocking position 10c, the second switching valve 12 is set to the communication position 12b, the motor 14 is rotated at a constant speed, and the liquid is supplied from the pump 13 into the rod side chamber 6. As a result, the piston side chamber 7 and the reservoir tank 8 are in communication, and the 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 the hydraulic cylinder a exerts a contracting thrust force. In this way, the hydraulic cylinder a can generate a thrust force that drives the pump 13 to contract the cylinder body 2, which is equal to a 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 if the pressure of the reservoir tank 8 is regarded as 0. Since the pressure of the rod side chamber 6 can be adjusted by adjusting the amount of current of the pressure control valve 22, the thrust in the contraction direction generated by the hydraulic cylinder a can be adjusted.

In the case of this hydraulic cylinder a, the cross-sectional area of the rod 5 is made half of the cross-sectional area of the piston 4, and the pressure receiving area of the piston 4 on the rod side chamber 6 side is made half of the pressure receiving area of the piston side chamber 7 side, and if the pressures of the rod side chamber 6 are made the same at the time of extension driving and at the time of contraction driving, the thrust forces generated by both expansion and contraction are equal, and the flow rate with respect to the displacement amount of the hydraulic cylinder a is also the same at both expansion and contraction sides. Therefore, when the thrust force of the hydraulic cylinder a is controlled, if the magnitudes of the thrust forces in the extension direction and the contraction direction are the same, the amounts of current applied to the pressure control valve 22 are also the same, so that the control of the hydraulic cylinder a becomes simple, and besides, the flow rate with respect to the displacement amount of the hydraulic cylinder a is also the same, so that there is an advantage that the responsiveness is the same on both sides of extension and contraction.

Since the hydraulic cylinder a of the present embodiment includes the rectifying passage 19 and the suction passage 20, if the first switching valve 10 and the second switching valve 12 each adopt the blocking positions 10c and 12c, the rod-side chamber 6, the piston-side chamber 7, and the reservoir tank 8 are connected in series in the rectifying passage 19, the suction passage 20, and the discharge passage 21, and function as a direct-flow damper. Therefore, when the motor 14, the first switching valve 10, the second switching valve 12, and the pressure control valve 22 of the hydraulic cylinder a fail to be energized, the valve bodies 10a, 12a of the first switching valve 10 and the second switching valve 12 are pressed by the springs 10d, 12d, and the cut-off positions 10c, 12c are adopted, respectively, and the pressure control valve 22 functions as a pressure control valve with the maximum valve opening pressure fixed, so that the hydraulic cylinder a automatically functions as a passive damper.

When the motor 14 is stopped and the pump 13 is not driven, the hydraulic cylinder a can generate a damping force only when the valve is extended or contracted in a state where only one of the first switching valve 10 and the second switching valve 12 is opened. In this way, the hydraulic cylinder a can exert a damping force of a desired height only in a desired direction, and thus can function as a semi-active damper.

As described above, the hydraulic cylinder a can function as an actuator by driving the pump 13, and also as a passive damper when the pump 13 is stopped, and can function as a semi-active damper by controlling the first switching valve 10, the second switching valve 12, and the pressure control valve 22 even when the pump 13 is stopped. In addition, the hydraulic cylinder a may function as an actuator that can expand and contract the cylinder body 2 by driving the pump 13, and in a state where the pump 13 is stopped, a thrust that prevents expansion and contraction may be generated when the cylinder body 2 expands and contracts due to an external force, and therefore, in this case, a structure other than the above may be adopted.

Next, as shown in fig. 3, the controller C of the present embodiment includes an acceleration sensor 40 for detecting a horizontal and lateral acceleration α with respect to the vehicle forward direction of the vehicle body B, a target thrust computing unit 41 for obtaining a target thrust of the hydraulic cylinder a, a torque detecting unit 42 for detecting a torque of the motor 14, an average computing unit 43 for obtaining an average Tma of the torque Tm detected by the torque detecting unit 42, a selecting unit 44 for selecting the hydraulic cylinder a to function as an actuator or as a passive damper based on the average Tma of the torque Tm obtained by the average computing unit 43, a rotation speed determining unit 45 for determining a rotation speed of the motor 14 based on a selection result of the selecting unit 44 and the average Tma of the torque Tm, a motor control unit 46 for controlling the motor 14, a pressure control valve control unit 47 for controlling the pressure control valve 22, a first switching valve control unit 48 for controlling the first switching valve 10, a second switching valve control unit 49 for controlling the second switching valve 12, and a control command generating unit 50 for selectively causing the hydraulic cylinder a to function as an actuator based on the average Tma of the torque Tm obtained by the average computing unit 43, a rotation speed determining unit 45 for determining a rotation speed of the hydraulic cylinder a corresponding to the motor 14, a speed control unit 46 for controlling the second switching valve control valve 48, and a railway vehicle body 1.

Hereinafter, each part of the controller C will be described in detail. The acceleration sensor 40 detects a horizontal lateral acceleration α with respect to the vehicle forward direction of the vehicle body B, and inputs the detected horizontal lateral acceleration α to the target thrust computing unit 41.

The target thrust calculating unit 41 filters and removes a steady acceleration, a drift component, or noise during traveling of a curve included in the acceleration α, integrates the filtered acceleration α to obtain a lateral velocity of the vehicle body B, and multiplies the obtained velocity by a hook damping coefficient to obtain a thrust to be output to the hydraulic cylinder a. For example, when the thrust in the direction of pushing the vehicle body B to the left in fig. 1 is a thrust in the direction of pushing the vehicle body B to the right in fig. 1, the target thrust calculating unit 41 obtains the value of the target thrust as a positive value, and conversely, when the thrust in the direction of pushing the vehicle body B to the right in fig. 1 is a thrust in the direction of pushing the vehicle body B, obtains the value of the target thrust as a negative value, and inputs a command for instructing the obtained target thrust to the control command generating unit 50.

Further, as described above, the target thrust calculating unit 41 calculates the target thrust according to the astronomical control law, but may calculate the target thrust using a control law other than the astronomical control law, for example, it is possible to extract a component of the resonance frequency band in the body B of the railway vehicle V from the acceleration α, weight the extracted component of the resonance frequency band of the acceleration α by frequency, and perform H infinity control on the target thrust for suppressing the vibration of the body B. The target thrust calculating unit 41 may grasp yaw vibration, which is lateral vibration of the vehicle body B, and yaw vibration, which is vibration in a rotational direction around the center of gravity of the vehicle body B, by providing the acceleration sensor 40 in front of and behind the vehicle body B, and determine a resultant force of the thrust for suppressing the yaw vibration and the thrust for suppressing the yaw vibration as the target thrust to be output to the hydraulic cylinder a.

The torque detection unit 42 monitors the current flowing to the motor 14, and detects the torque output from the motor 14. Since a current sensor is provided in the motor 14 or a driving circuit of the motor control unit 46 described below to drive the motor 14, the torque detection unit 42 can monitor the current using the current sensor. In the cylinder device 1 of the present embodiment, the controller C drives the motor 14 at the predetermined normal rotation speed RN of the motor 14 to drive the pump 13 when detecting the torque, but in order to open the first switching valve 10 and the second switching valve 12, the hydraulic cylinder a is in an unloaded state in which thrust is not exerted. Therefore, since the hydraulic cylinder a is in the unloaded state, the torque detection unit 42 detects the torque Tm corresponding to the line resistance in the hydraulic cylinder a, and in order to detect the torque Tm corresponding to the magnitude of the kinematic viscosity of the hydraulic oil, the lower the temperature of the hydraulic oil is, the higher the torque Tm is detected.

In addition, as described above, in a state in which the motor 14 is driven at the normal rotation speed RN, the torque detection unit 42 monitors the current of the motor 14, and therefore the torque detection unit 42 can grasp the current and the rotation speed flowing to the motor 14. Further, 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, the current, and the characteristics of the motor 14 by monitoring the current of the motor 14. The torque detection unit 42 may be a torque sensor that detects an output shaft torque of the motor 14 other than the one shown in the figure.

After the motor 14 is started from the stopped state, the average value calculating unit 43 obtains an average value Tma of the torque Tm detected by the torque detecting unit 42 for a predetermined period of time. Specifically, the average value calculating unit 43 divides the sum of the values of the torque Tm detected by the torque detecting unit 42 in a predetermined sampling period by the number of samples of the sampled torque Tm to obtain the average value Tma during a predetermined time period after the motor 14 is started. The predetermined time is, for example, about 5 seconds. The predetermined time may be determined in consideration of the processing time of the torque detection unit 42, the selection unit 44, and the rotation speed determination unit 45 so that the torque detection unit 42 can calculate the average value Tma when the railway vehicle V temporarily stops at the stop, the selection unit 44 described below performs the selection process, and the rotation speed determination unit 45 can perform and end the rotation speed determination process.

The average value calculation unit 43 may simulate and calculate the average value Tma of the torque Tm by performing a low-pass filter process on the torque Tm detected during a predetermined time after the motor 14 is started from the stopped state.

The selecting unit 44 selects whether to cause the hydraulic cylinder a to function as an actuator or to function as a passive damper based on the torque Tm detected by the torque detecting unit 42. Specifically, the selection unit 44 acquires the speed of the railway vehicle V from a vehicle monitor outside the figure in the railway vehicle V, counts the time after the railway vehicle V is stopped, and executes the selection process when the counted time is equal to or longer than a predetermined stop time. The controller C may be provided with a sensor for detecting the speed of the railway vehicle V alone, and may detect the speed by using the sensor. The parking time is set to, for example, about 5 seconds, and is set to a time period in which the degree of parking at a parking station, a railway base, or the like can be recognized.

When the selection process is started, the selection unit 44 inputs an instruction to execute the selection process to the control instruction generation unit 50. When an instruction to execute the selection process is given, the control instruction generating unit 50 outputs an instruction to open the first switching valve 10 to the first switching valve control unit 48, and outputs an instruction to open the second switching valve 12 to the second switching valve control unit 49, so that the hydraulic cylinder a is in the unloaded state, and then outputs an instruction to start the motor 14 and drive the motor at the predetermined normal rotation speed RN to the motor control unit 46, so that the motor 14 is driven at the normal rotation speed RN.

When the selection process by 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 obtains an average value Tma of the torque Tm detected until a predetermined time elapses after the motor 14 is started, and outputs the average value Tma to the selection unit 44.

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 the passive damper mode to function the hydraulic cylinder a as a passive damper. On the other hand, when the average value Tma of the torque Tm is smaller than the first torque threshold value T1, the selection unit 44 selects the actuator mode to function the hydraulic cylinder a as an actuator. The selecting unit 44 outputs the selection result of which of the actuator and the passive damper is selected to the control command generating unit 50. In the selection process of the selection unit 44, the motor 14 is driven to detect the torque Tm of the motor 14, but since the hydraulic cylinder a is set to the unloaded state, the hydraulic cylinder a does not generate a thrust force to shake the vehicle body B, and therefore the railway vehicle V can safely perform the selection process even in operation.

The torque Tm of the motor 14 increases in proportion to the kinematic viscosity of the hydraulic oil in the hydraulic cylinder a, and therefore a higher average value Tma means a higher kinematic viscosity of the hydraulic oil. If the kinematic viscosity of the hydraulic oil is too high, the pressure loss in the hydraulic cylinder a becomes too large and the thrust force becomes too high when the motor 14 is driven to function as the actuator, and the vibration damping performance of the vehicle body B is deteriorated.

The first torque threshold T1 is set to a value of the torque Tm of the motor 14 to be detected when the temperature of the hydraulic oil is low and the kinematic viscosity of the hydraulic oil becomes a value of such a degree that the vibration damping property of the vehicle body B is deteriorated. Therefore, as described above, the selection unit 44 compares the average value Tma with the first torque threshold value T1, and as a result, when the average value Tma is equal to or greater than the first torque threshold value T1 and the kinematic viscosity of the hydraulic oil is high, the vibration damping performance of the vehicle body B may be deteriorated, and therefore, selects the hydraulic cylinder a as the passive damper, whereas when the average value Tma is smaller than the first torque threshold value T1 and the kinematic viscosity of the hydraulic oil is not a height that deteriorates the vibration damping performance of the vehicle body B even if the hydraulic cylinder a is used as the actuator, the hydraulic cylinder a is selected as the actuator.

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 or not the kinematic viscosity is excessive at the current time by monitoring the kinematic viscosity of the hydraulic oil when the selection process is performed and comparing the average value Tma with the first torque threshold T1.

Here, when the motor 14 is rotated from the stopped state, the torque Tm at the time of starting the motor 14 becomes large, and the torque Tm fluctuates before the torque Tm of the motor 14 stabilizes. Therefore, if the torque Tm detected by the torque detecting portion 42 is directly used in the selecting portion 44, the kinematic viscosity of the hydraulic oil may not be adequately grasped. In contrast, in the present embodiment, the controller C includes the average value calculation unit 43, and the selection unit 44 selects one of the actuator mode and 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, a mode suitable for the kinematic viscosity of the hydraulic oil can be selected from the actuator mode and the passive damper mode with high accuracy.

Instead of obtaining the average value Tma, the selecting unit 44 may perform the selection process using the torque Tm detected after the torque Tm has stabilized after the motor is started for 14 seconds. In contrast, in the cylinder device 1 of the present embodiment, since the average value Tma is obtained for the predetermined time period from the start of the motor 14, the selection process by the selection unit 44 can be executed with high accuracy even if the torque Tm is unstable, and therefore, the selection process can be completed in a shorter time period than in the case of using the torque Tm detected after the torque Tm is stable, and the selection process can be executed in time in a very short time period when the railway vehicle V is stopped at the stop.

Next, the rotation speed determining unit 45 receives an input of a selection result from the selecting unit 44, compares the value of the average value Tma of the torque Tm with the second torque threshold T2 when the selecting unit 44 selects the actuator, determines the rotation speed of the motor 14 based on the comparison result, and determines the rotation speed of the motor 14 to be 0 when the selecting unit 44 selects the passive damper mode.

When the selection portion 44 selects the passive damper mode, if the motor 14 is driven, the hydraulic cylinder a functions as an actuator, and therefore the rotation speed of the motor 14 is set to 0 to stop the motor 14 and the hydraulic cylinder a can function as a passive damper.

On the other hand, when the selection unit 44 selects the actuator mode, the rotation speed determination unit 45 determines that the rotation speed of the motor 14 is set to the predetermined low rotation speed RL when the value of the average value Tma of the torque Tm is equal to or greater than the second torque threshold T2, and determines that the rotation speed of the motor 14 is set to the predetermined normal rotation speed RN when the value of the average value Tma of the torque Tm is smaller than the second torque threshold T2. The second torque threshold T2 is set to a value lower than the first torque threshold T1, and when the average value Tma is smaller than the first torque threshold T1, the selection unit 44 selects the actuator mode, so that the rotation speed determination unit 45 determines the rotation speed at which the motor 14 is driven at the low rotation speed RL when T1> Tma ≡t2, and determines the rotation speed at which the motor 14 is driven at the normal rotation speed RN when T2> Tma. The rotation speed determination unit 45 may determine the rotation speed of the motor 14 to be driven at the low rotation speed RL when T1> Tma > T2, and determine the rotation speed of the motor 14 to be driven at the normal rotation speed RN when T2> Tma, instead of receiving the input of the selection result from the selection unit 44.

In this way, when the selection unit 44 selects the hydraulic cylinder a to function as the actuator, the rotation speed determining unit 45 sets the rotation speed of the motor 14 to the low rotation speed RL lower than the normal rotation speed RN when the kinematic viscosity of the hydraulic oil is high, the pressure loss in the hydraulic cylinder a is large, and the thrust tends to be large, and sets the rotation speed of the motor 14 to the normal rotation speed RN higher than the low rotation speed RL when the kinematic viscosity of the hydraulic oil is low and there is no fear that the thrust of the hydraulic cylinder a becomes excessive. In consideration of the specification of the hydraulic cylinder a, the normal rotation speed RN is set in advance as the rotation speed of the motor 14 so that the kinematic viscosity of the hydraulic oil is in a range suitable for normal use, and the thrust force is suitable 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 at which the thrust force of the hydraulic cylinder a is not excessively large even when the railway vehicle V is running in a cold region and the temperature of the hydraulic oil is low and the kinematic viscosity becomes high. When determining the rotation speed of the motor 14, the rotation speed determining unit 45 inputs the determined rotation speed to the control command generating unit 50.

In this way, the second torque threshold T2 becomes a torque with the rotation speed of the motor 14 as a reference for selecting a rotation speed suitable for the kinematic viscosity of the hydraulic oil. Specifically, the temperature of the hydraulic oil is higher and the kinematic viscosity of the hydraulic oil is lower than the kinematic viscosity of the hydraulic oil when the torque Tm is equal to or higher than the first torque threshold T1, but when the motor 14 is driven at the predetermined normal rotation speed RN, the thrust force of the hydraulic cylinder a may be excessively large, and the riding comfort of the vehicle body B may be impaired. Therefore, the second torque threshold T2 is set to a value of the torque Tm of the motor 14 to be detected when the kinematic viscosity of the hydraulic oil becomes a value that causes the thrust force of the hydraulic cylinder a to become excessively large when the motor 14 is driven at the prescribed normal rotation speed RN.

The control command generating 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 on-off valve control unit 48, and the second on-off valve control unit 49 based on the speed of the railway vehicle V input from the vehicle monitor outside the figure, the target thrust obtained by the target thrust calculating unit 41, the selection result of the selecting unit 44, and the rotation speed of the motor 14 determined by the rotation speed determining unit 45.

When the speed of the railway vehicle V is lower than the predetermined control start speed, the control command generating unit 50 issues a command to 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 so that the hydraulic cylinder a functions as a passive damper, independently of the target thrust calculating unit 41 and the selection result of the selecting unit 44. That is, when the speed of the railway vehicle V is lower than the control start speed, the control command generating unit 50 generates a motor control command for stopping the motor 14, a pressure control valve control command for maximizing the valve opening pressure without energizing the pressure control valve 22, a first valve opening/closing control command for closing the first valve 10 and the second valve 12, and a second valve opening/closing control command, and inputs the corresponding control commands to the motor control unit 46, the pressure control valve control unit 47, the first valve opening/closing control unit 48, and the second valve opening/closing control unit 49. The control start speed may be arbitrarily set to a speed required to actively damp the vibration of the vehicle body B by causing the hydraulic cylinder a to function as an actuator when the vibration of the railway vehicle V increases.

When the speed of the railway vehicle V is equal to or higher than the predetermined control start speed, the control command generating unit 50 generates respective control commands to be input 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 selection result of the selecting unit 44.

When the speed of the railway vehicle V is equal to or higher than the predetermined control start speed, but the selection unit 44 selects the passive damper mode, similarly to the case where the speed of the railway vehicle V is lower than the predetermined control start speed, 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, maximize the valve opening pressure without energizing the pressure control valve 22, and close the first on-off valve 10 and the second on-off valve 12 so as to cause the hydraulic cylinder a to function as a passive damper.

On the other hand, when the speed of the railway vehicle V is equal to or higher than the predetermined control start speed, but the selection unit 44 selects the actuator mode, the control command generation unit 50 generates and supplies the pressure valve control command, the first on-off valve control command, and the second on-off valve control command to the pressure control valve control unit 47, the first on-off valve control unit 48, and the second on-off valve control unit 49 in accordance with the instruction of the target thrust obtained by the target thrust calculation unit 41, and generates and supplies the motor control command instructing to drive the motor 14 in accordance with the rotation speed determined by the rotation speed determination unit 45 to the motor control unit 46.

Specifically, the control command generating unit 50 generates a pressure control valve control command for instructing the current supplied to the pressure control valve 22 from the value obtained by the target thrust calculating unit 41 and excluding the sign, and inputs the command to the pressure control valve control unit 47. As described above, the magnitude of the thrust force can be adjusted by the valve opening pressure of the pressure control valve 22 irrespective of the direction of the thrust force of the hydraulic cylinder a, and therefore the valve opening pressure of the pressure control valve 22 for outputting the target thrust force to the hydraulic cylinder a can be uniquely obtained from the target thrust force. Further, since the valve opening pressure of the pressure control valve 22 can be adjusted by the current supplied to the proportional solenoid 22c in the pressure control valve 22, the control command generating unit 50 obtains the amount of current to be supplied to the proportional solenoid 22c of the pressure control valve 22 from the value of the target thrust obtained by the target thrust calculating unit 41, generates a pressure control valve control command indicating the amount of current supplied to the proportional solenoid 22c, and outputs the pressure control valve control command to the pressure control valve control unit 47.

Further, since the symbol in the value of the target thrust indicates the direction of the thrust to be output by the hydraulic cylinder a, the control command generating unit 50 generates the first and second on/off valve control commands for controlling the opening/closing of the first and second on/off valves 10 and 12 based on the symbol. When the symbol indicates that the hydraulic cylinder a is generating thrust in the extension direction, the control command generating unit 50 generates a first on-off valve control command for opening the first on-off valve 10, and inputs the first on-off valve control command to the first on-off valve control unit 48, and generates a second on-off valve control command for closing the second on-off valve 12, and inputs the second on-off valve control command to the second on-off valve control unit 49. On the other hand, when the symbol indicates that the hydraulic cylinder a is generating thrust in the contraction direction, the control command generating unit 50 generates a first on-off valve control command for closing the first on-off valve 10, and inputs the first on-off valve control unit 48, and generates a second on-off valve control command for opening the second on-off valve 12, and inputs the second on-off valve control command to the second on-off valve control unit 49.

Further, the control command generating unit 50 generates a motor control command to drive the motor 14 at the rotation speed determined by the rotation speed determining unit 45 so as to cause the hydraulic cylinder a to function as an actuator, and inputs the motor control command to the motor control unit 46.

As described above, the control command generating unit 50 causes the hydraulic cylinder a to function as a passive damper when the speed of the railway vehicle V is lower than the control start speed, regardless of the selection result of the selecting unit 44, causes the hydraulic cylinder a to function as a passive damper when the speed of the railway vehicle V is equal to or higher than the control start speed and the selection result of the selecting unit 44 selects the passive damper mode, and causes the hydraulic cylinder a to function as an actuator when the speed of the railway vehicle V is equal to or higher than the control start speed and the selection result of the selecting unit 44 selects the actuator mode. Further, when the hydraulic cylinder a is caused to function as an actuator, the control command generation unit 50 drives the motor 14 at the rotation speed determined by the rotation speed determination unit 45.

When the command for starting the selection process is input from the selection unit 44 as described above, the control command generation unit 50 outputs the first on/off valve control command for opening 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 the second on/off valve control command for opening the second on/off valve 12 to the second on/off valve control unit 49 to open the second on/off valve 12, and simultaneously outputs the motor control command for starting the motor 14 and driving the motor at the normal rotation speed RN to the motor control unit 46 to drive the motor 14 at the normal rotation speed RN.

Next, the motor control unit 46 drives the motor 14 at the rotation speed indicated by the motor control command input from the control command generation unit 50. The motor control unit 46 is not shown, and is configured as a motor driver having a drive circuit for supplying current to the motor 14, and controlling the drive circuit by monitoring the current and the rotation speed flowing to the motor 14, and controlling the motor 14 to the rotation speed instructed by the rotation speed determining unit 45.

The motor control unit 46 detects the current and the rotation speed of the motor 14 and performs feedback control, and when the control command generation unit 50 instructs to stop the motor 14, the motor 14 is stopped without energizing the motor 14, when the rotation speed instructed by the control command generation unit 50 is the normal rotation speed RN, the motor 14 is energized so that the rotation speed of the motor 14 matches the normal rotation speed RN, and when the rotation speed instructed by the control command generation unit 50 is the low rotation speed RL, the motor 14 is energized so that the rotation speed of the motor 14 matches the low rotation speed RL.

When the speed of the railway vehicle V is lower than the predetermined control start speed, the control command generating unit 50 instructs to stop the motor 14, and therefore the motor control unit 46 stops the motor 14 without driving the motor 14. Further, when the selection process of the selection unit 44 is performed, if the condition for the selection unit 44 to perform the selection process is that the railway vehicle V is stopped and the speed of the railway vehicle V is less than the control start speed, the control instruction generation unit 50 inputs a motor control instruction instructing the motor 14 to stop to the motor control unit 46. Therefore, the motor control unit 46 must start the motor 14 in a stopped state when executing the selection process.

The pressure control valve control unit 47 supplies a current indicated by the 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. The pressure control valve control unit 47 is not shown, and is provided with a drive circuit for supplying current to the proportional solenoid 22c, and a solenoid driver for monitoring the current flowing to the proportional solenoid 22c, PWM-controlling the drive circuit, and controlling the amount of current flowing to the proportional solenoid 22c to the amount of current instructed from the control command generation unit 50.

The first on-off valve control unit 48 opens and closes the first on-off valve 10 as instructed by the first on-off valve control command input from the control command generation unit 50. When the first on-off valve control command instructs the first on-off valve 10 to close, the first on-off valve control unit 48 does not energize the solenoid 10e of the first on-off valve 10 and takes the first on-off valve 10 as the cut-off position 10c. On the other hand, when the first on-off valve control command instructs the first on-off valve 10 to open, the first on-off valve control unit 48 energizes the solenoid 10e of the first on-off valve 10 to energize the solenoid 10e, and sets the first on-off valve 10 as the communication position 10b. The first on-off valve control unit 48 is not shown, and has a drive circuit including a switch, and switches between a solenoid driver for energizing and de-energizing the solenoid 10e by switching on/off of the switch.

The second on-off valve control unit 49 opens and closes the second on-off valve 12 as instructed by the second on-off valve control command input from the control command generation unit 50, similarly to the first on-off valve control unit 48. When the second on-off valve control command instructs the second on-off valve 12 to close, the second on-off valve control unit 49 does not energize the solenoid 12e of the second on-off valve 12 and takes the second on-off valve 12 as the blocking position 12c. On the other hand, when the second on-off valve control command instructs the second on-off valve 12 to open, the second on-off valve control unit 49 energizes the solenoid 12e of the second on-off valve 12 to energize the solenoid 12e, and sets the second on-off valve 12 as the communication position 12b. The second on-off valve control unit 49 is not shown, and has a drive circuit including a switch not shown, and switches between on and off of the switch to switch the solenoid driver for energizing and deenergizing the solenoid 12 e.

The controller C is not shown, but may include, as hardware resources, a CPU (Central Processing Unit ) that executes other programs for controlling the operating system and the motor 14, the first switching valve 10, the second switching valve 12, and the pressure control valve 22, a storage device such as a ROM (Read Only Memory) that stores programs necessary for the control, a storage device such as a RAM (Random Access Memory ) that provides a storage area to the CPU, and interfaces for exchanging signals among the CPU, the acceleration sensor 40, the motor control unit 46, the pressure control valve control unit 47, the first switching valve control unit 48, and the second switching valve control unit 49, for example.

The target thrust calculating unit 41, the torque detecting unit 42, the average calculating unit 43, the selecting unit 44, the rotation speed determining unit 45, and the control command generating unit 50 in the controller C are realized by executing a program for performing the above-described control by a CPU.

First, a selection process of selecting whether to make the hydraulic cylinder a of the controller C function as a passive damper or as an actuator will be described with reference to a flowchart shown in fig. 4.

In the selection process, in order to determine whether or not the condition for executing the selection process is satisfied, the controller C determines whether or not the time for stopping the railway vehicle V is equal to or longer than a predetermined stop time after the speed of the railway vehicle V is reduced and the railway vehicle V is stopped (step S1). When it is determined whether or not the parking time is equal to or longer than the predetermined parking time, since the railway vehicle V has already been parked, the motor 14 is stopped and both the first switching valve 10 and the second switching valve 12 are closed because the hydraulic cylinder a is not controlled to function as an actuator but as a passive damper as described above.

In the judgment in step S1, when the time for which the railway vehicle V is stopped is smaller than the predetermined stop time, the time is counted, and the judgment in step S1 is repeated. On the other hand, in the judgment in step S1, when the time for which the railway vehicle V is stopped is equal to or longer than the predetermined stop time, since the condition for executing the selection process of selecting one of the actuator mode and the passive damper mode is provided, the controller C opens the first switching valve 10 and the second switching valve 12, and thereafter drives the motor 14 at the normal rotation speed RN to supply the hydraulic oil from the pump 13 into the cylinder 3 in order to execute the selection process (step S2). In a state where the first and second switching valves 10 and 12 are opened, even if the rod-side chamber 6 and the piston-side chamber 7 communicate with the reservoir tank 8 via the first and second passages 9 and 11 to drive the pump 13, the hydraulic oil returns to the reservoir tank 8 via the cylinder 3, so that the hydraulic cylinder a is in an unloaded state without generating thrust.

Next, the controller C reads the torque Tm of the motor 14 detected until a predetermined time elapses from the start of the motor 14, and obtains a mean value Tma of the torque Tm (step S3). Then, the controller C determines whether or not the average value Tma is equal to or greater than the first torque threshold T1 in order to select the hydraulic cylinder a to function as an actuator or as a passive damper (step S4).

In the determination in step S4, when the average value Tma is equal to or greater than the first torque threshold value T1, the hydraulic cylinder a is not suitable to function as an actuator because of the high kinematic viscosity of the hydraulic oil, and therefore, the passive damper mode in which the hydraulic cylinder a functions as a passive damper is selected (step S5). After stopping the driving of the motor 14, the controller C closes the first switching valve 10 and the second switching valve 12 (step S6), and ends the process.

In the determination in step S4, if the average value Tma is smaller than the first torque threshold value T1, the movement viscosity of the hydraulic oil is low, and the hydraulic cylinder a can be caused to function as an actuator, so that the controller C selects the actuator mode, and proceeds to step S7, and determines whether the average value Tma is smaller than the first torque threshold value T1 and equal to or larger than the second torque threshold value T2 in order to determine whether the movement 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. In the determination in step S7, since the average value Tma is smaller than the first torque threshold value T1 in the determination in step S4, it is sufficient to determine whether or not the average value Tma is equal to or greater than the second torque threshold value T1.

In the determination in step S7, when the average value Tma is smaller than the first torque threshold value T1 and equal to or greater than the second torque threshold value T2, the kinematic viscosity of the hydraulic oil increases while the hydraulic cylinder a functions as an actuator, and when the motor 14 is driven at the normal rotation speed RN, the thrust force of the hydraulic cylinder a tends to increase, so the controller C determines to use the low rotation speed RL and sets the rotation speed of the motor 14 to the low rotation speed RL (step S8).

After setting the rotation speed of the motor 14 in step S8, the controller C proceeds to step S6, and stops driving of the motor 14 to close the first switching valve 10 and the second switching valve 12.

In the determination in step S7, when the average value Tma is smaller than the second torque threshold T2, the kinematic viscosity of the hydraulic oil is reduced to such an extent that the hydraulic cylinder a functions as an actuator and is suitable for driving the motor 14 at the normal rotation speed RN, and therefore the controller C decides to employ 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, and stops driving of the motor 14 to close the first switching valve 10 and the second switching valve 12.

In this way, the controller C executes the selection process to select either one of the actuator mode in which the hydraulic cylinder a functions as an actuator or the passive damper mode in which the hydraulic cylinder a functions as a passive damper, if the time for which the railway vehicle V is parked is equal to or longer than the predetermined parking time each time the railway vehicle V is parked. Therefore, one of the actuator and the passive damper suitable for suppressing the vibration of the vehicle body B can be selected to function as the hydraulic cylinder a according to the air temperature of the area where the railway vehicle V runs. Further, since the selection process is performed during the parking of the railway vehicle V, even in the case where the route along which the railway vehicle V travels is set to include a warm region and a cold region, any one of the actuator and the passive damper is selected in accordance with a change in the kinematic viscosity of the hydraulic oil every time the railway vehicle V is parked, and therefore the vibration of the vehicle body B can be effectively suppressed in correspondence with the region temperature along which the railway vehicle V travels.

Next, according to the flowchart shown in fig. 5, the control of the hydraulic cylinder a in the controller C during running of the railway vehicle V will be described.

When the speed of the railway vehicle V during traveling is lower than the control start speed, the hydraulic cylinder a does not function as an actuator, and when the speed of the railway vehicle V is equal to or higher than the control start speed, the controller C determines whether or not the speed of the railway vehicle V input from the vehicle monitor outside the figure is equal to or higher than the control start speed in this state because the hydraulic cylinder a can be caused to function as an actuator (step S11).

In the determination at step S11, when the speed of the railway vehicle V is lower than the control start speed, the controller C stops the motor 14 to cause the hydraulic cylinder a to function as a passive damper, closes the first switching valve 10 and the second switching valve 12, and maximizes the valve opening pressure without energizing the pressure control valve 22, thereby causing the hydraulic cylinder a to function as a passive damper (step S12).

On the other hand, in the judgment in step S11, when the speed of the railway vehicle V is equal to or higher than the control start speed, the controller C judges whether or not the actuator mode is selected (step S13), and when the actuator mode is selected, the controller calculates the target thrust so that the hydraulic cylinder a functions as an actuator (step S14).

Then, the flow proceeds to step S15, and the controller C drives the motor 14 at the rotation speed determined in accordance with the selection process, and, in order to output the thrust indicated by the target thrust to the hydraulic cylinder a, switches the opening/closing of the first switching valve 10 and the second switching valve 12 while adjusting the valve opening pressure of the pressure control valve 22, so that the hydraulic cylinder a outputs the thrust equal to the target thrust.

On the other hand, if the actuator mode is not selected and the passive damper mode is selected in the judgment of step S11, the controller C proceeds to step S16, and stops the motor 14 to close the first switching valve 10 and the second switching valve 12, and the pressure control valve 22 is not energized to maximize the valve opening pressure, thereby allowing the hydraulic cylinder a to function as a passive damper.

When the speed of the railway vehicle V is equal to or higher than the control start speed, the hydraulic cylinder a functions as an actuator to output the target thrust force obtained by the controller C, and when the speed of the railway vehicle V is equal to or higher than the control start speed, the passive damper mode is selected by the selection process, or the speed of the railway vehicle V is lower than the control start speed. Also, when the railway vehicle V is stopped, a selection process is performed by the controller C to select one of the actuator mode or the passive damper mode.

As described above, the cylinder device 1 of the present embodiment includes the hydraulic cylinder a, which has the cylinder body 2 that expands and contracts due to the supply of the hydraulic oil (working fluid), the pump 13 that supplies the hydraulic oil (working fluid) to the cylinder body 2, and the motor 14 that drives the pump 13, and which can function as an actuator by the driving of the pump 13 and can function as a passive damper when the pump 13 is stopped, and the controller C that controls the motor 14 includes the torque detection unit 42 that detects the torque Tm of the motor 14, and the selection unit 44 that selects either the actuator mode that causes the hydraulic cylinder a to function as an actuator or the passive damper mode that functions as a passive damper based on the torque Tm detected by the torque detection unit 42.

According to the cylinder device 1 configured in this way, since either the actuator mode or the passive damper mode is selected based on the torque Tm of the motor 14 that varies according to the kinematic viscosity of the hydraulic oil (working fluid) of the hydraulic cylinder a, it is possible to determine with high accuracy which of the actuator mode and the passive damper mode is suitable for the kinematic viscosity of the current hydraulic oil (working fluid), and it is possible to generate an appropriate thrust force corresponding to the variation in the kinematic viscosity of the hydraulic oil (working fluid).

Therefore, according to the cylinder device 1 of the present embodiment, even if the external temperature changes, the vibration of the vehicle body B of the railway vehicle V can be suppressed with high efficiency, and the kinematic viscosity of the hydraulic oil (working fluid) can be grasped with high accuracy, so that it is possible to control the kinematic viscosity suitable for the actual hydraulic oil (working fluid) and to improve the riding comfort of the railway vehicle V, as compared with the conventional cylinder device in which the temperature of the hydraulic oil (working fluid) is estimated from the date or position information or the temperature of the hydraulic oil (working fluid) is directly detected.

In the cylinder device 1 of the present embodiment, the controller C includes a rotation speed determining unit 45 that determines the rotation speed of the motor 14 based on the torque Tm.

According to the cylinder device 1 configured in this way, when the hydraulic cylinder a is caused to function as an actuator, the motor 14 can be driven at a rotational speed suitable for the kinematic viscosity of the hydraulic oil, and therefore, the thrust force output by the hydraulic cylinder a can be suppressed from becoming excessive. Further, according to the cylinder device 1 of the present embodiment, by using the hydraulic cylinder a in the railway vehicle V, the thrust of the hydraulic cylinder a functioning as an actuator can be suppressed from being higher than the target thrust, and therefore, even if the air temperature changes, the riding comfort of the vehicle can be improved.

Further, according to the cylinder device 1 of the present embodiment, even when feedback control is performed on the thrust force of the hydraulic cylinder a, the thrust force is not excessive even if the kinematic viscosity of the hydraulic oil (working fluid) is high, and therefore, the error between the target thrust force and the actual output thrust force is small, and the oscillation in which the thrust force of the hydraulic cylinder a oscillates is also reduced, and the problem that the oscillation condition is deteriorated due to the vibration of the body B of the railway vehicle does not occur.

Further, in the cylinder device 1 of the present embodiment, the controller C causes the hydraulic cylinder a to function as a passive damper when the torque Tm is equal to or greater than the first torque threshold T1, causes the motor 14 to function as an actuator when the torque Tm is equal to or greater than the first torque threshold T1 and is equal to or greater than the second torque threshold T2 which is lower than the first torque threshold T1, and causes the motor 14 to function as an actuator when the torque Tm is equal to or less than the second torque threshold T2 and causes the motor 14 to function as an actuator when the torque Tm is less than the second torque threshold T2 and is greater than the normal rotation speed RN which is higher than the low rotation speed R1.

According to the cylinder device 1 configured in this way, the first torque threshold value T1 and the second torque threshold value T2 are set with respect to the torque Tm, and by comparing the torque Tm with these first torque threshold value T1 and second torque threshold value T2, it is possible to easily perform switching between the actuator mode and the passive damper mode and switching of the rotation speed of the motor 14, and to generate an appropriate thrust force according to the kinematic viscosity of the hydraulic oil (working fluid).

In the cylinder device 1 of the present embodiment, the controller C includes a mean value calculation unit 43, and the mean value calculation unit 43 obtains a mean value Tma of the torque Tm detected within a predetermined time after the motor 14 is started from the stopped state, and the selection unit 44 selects one of the actuator mode and the passive damper mode based on the mean value Tma of the torque Tm.

According to the cylinder device 1 configured in this way, the selecting 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 detecting unit 42 fluctuates, it is possible to accurately select which of the actuator and the passive damper is suitable for the kinematic viscosity of the hydraulic oil, and it is possible to finish the selection process in a short time. Therefore, when the cylinder device 1 is used for the railway vehicle V, the selection process can be performed even when the vehicle is parked in a very short time at the stop, and the selection process can be performed in time every time the vehicle is parked at the stop, so that the hydraulic cylinder a functions as one of the actuators and the passive dampers that is suitable for the kinematic viscosity of the hydraulic oil (working fluid), and the riding comfort of the vehicle is improved.

Further, in the cylinder device 1 of the present embodiment, the hydraulic cylinder a is interposed between the bogie T and the vehicle body B of the railway vehicle V, and when the stopped state of the railway vehicle V continues for a predetermined stop time, the selection unit 44 selects one of the actuator mode and the passive damper mode. In the cylinder device 1 configured in this way, since the selection unit 44 performs the selection process when the stopped state of the railway vehicle V continues for a predetermined stop time, the selection process can be performed when the railway vehicle V is stopped at a stop or the like, and the selection process can be performed in time to cause the hydraulic cylinder a to function as one of the actuators and the passive dampers that is suitable for the kinematic viscosity of the hydraulic oil (working fluid), so that the riding comfort of the vehicle can be improved.

As described above, the cylinder device 1 is applied to the railway vehicle V, but the cylinder device 1 may be applied to various devices other than the railway vehicle V, such as construction machines, ships, and airplanes.

The description of the embodiments of the present invention is completed above, but the scope of the present invention is of course not limited to the details shown or described.

Symbol description

1. Cylinder device

2. Cylinder body

13. Pump with a pump body

14. Motor with a motor housing

42. Torque detection unit

43. Average value calculation unit

44. Selection part

45. Rotation speed determining part

A hydraulic cylinder

B vehicle body

C controller

T-shaped bogie

V railway vehicle

Claims

1. A cylinder assembly, comprising:

A hydraulic cylinder comprises a cylinder body that extends and retracts due to the supply of working fluid, a pump that supplies the working fluid to the cylinder body, and a motor that drives the pump. It functions as an actuator when driven by the pump and as a passive damper when the pump stops.

The controller controls the motor;

The controller includes:

A torque detection unit detects the torque of the motor; and

The selection unit selects, based on the torque detected by the torque detection unit, either an actuator mode that functions as an actuator or a passive damper mode that functions as a passive damper.

2. The cylinder device according to claim 1, wherein...

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

3. The cylinder device according to claim 1, wherein...

Regarding the controller...

When the torque is above a first torque threshold, the hydraulic cylinder functions as a passive damper.

When the torque is less than the first torque threshold and greater than or equal to a second torque threshold below the first torque threshold, the motor is driven at a low speed, thereby enabling the hydraulic cylinder to function as an actuator.

When the torque is less than the second torque threshold, the motor is driven at a normal speed higher than the low speed, so that the hydraulic cylinder functions as an actuator.

4. The cylinder device according to any one of claims 1 to 3, wherein

The controller includes:

The average value calculation unit calculates the average value of the torque detected within a specified time after the motor is started from a stopped state.

The selection unit selects either the actuator mode or the passive damper mode based on the average value of the torque.

5. The cylinder device according to claim 1, wherein...

The hydraulic cylinder is installed between the bogie and the car body of the railway vehicle.

When the railway vehicle remains stationary for a specified period of time, the selection unit selects either the actuator mode or the passive damper mode.