CN113775687A - Cylinder device - Google Patents

Abstract

The invention provides a cylinder device capable of generating a set damping force even in high-speed expansion and contraction. The cylinder device is provided with: a cylinder; a piston slidably inserted into the cylinder and coupled to one end of the rod, and dividing the inside of the cylinder into a rod-side chamber and a piston-side chamber filled with a liquid; a liquid storage tank for storing gas and liquid; a valve housing closing an end of the cylinder; a bottom cover forming a liquid chamber with the valve housing; a discharge passage communicating the rod-side chamber with the liquid chamber without communicating with the liquid reservoir; a suction passage provided to the valve housing; a damping valve disposed in the discharge passage; and a check valve provided in the valve housing and setting the suction passage to a one-way passage that allows only the liquid to flow from the liquid reservoir to the piston-side chamber; wherein the discharge passage has an unbranched in-cap passage.

Description

Cylinder device

Technical Field

The present invention relates to a cylinder device.

Background

Conventionally, as such a cylinder device, for example, a damper is known which is mounted between a vehicle body and a bogie of a railway vehicle and suppresses vibration of the vehicle body in the lateral direction with respect to the vehicle traveling direction.

Specifically, this cylinder device includes: a cylinder; a rod member movably inserted into the cylinder; a piston slidably inserted into the cylinder and coupled to one end of the rod, and dividing the inside of the cylinder into a rod-side chamber and a piston-side chamber filled with hydraulic oil; an outer cylinder disposed on the outer periphery of the cylinder; a liquid storage tank formed by an annular gap between the cylinder and the outer cylinder; a discharge passage for communicating the rod side chamber with the liquid storage tank; a suction passage communicating the liquid reservoir with the piston-side chamber; a damping valve disposed in the discharge passage; a check valve provided in the suction passage and allowing only hydraulic oil to flow from the reservoir to the piston-side chamber; and a rectifying passage provided to the piston and allowing only hydraulic oil to flow from the piston-side chamber to the rod-side chamber, the cylinder device being a one-way type passive shock absorber.

Further, the discharge passage is formed by a passage provided to a rod guide fitted to an end of the cylinder on the rod chamber side and a pipe mounted on the rod guide and accommodated in the liquid reservoir.

Japanese patent application laid-open No. 2014-149003

Summary of The Invention

Problems to be solved by the invention

In the cylinder device configured in this way, when the cylinder device performs an expansion operation, hydraulic oil is discharged from the compressed rod-side chamber to the reservoir tank through the discharge passage, and hydraulic oil of the volume portion where the rod is withdrawn from the cylinder is replenished from the reservoir tank to the enlarged piston-side chamber through the suction passage.

As described above, the discharge passage is formed by the conduit accommodated in the reservoir tank, and the flow of the hydraulic oil, the flow rate of which is increased by the flow rate of the hydraulic oil flowing through the damping valve, is rectified by the conduit, and the hydraulic oil is discharged into the reservoir tank to prevent the gas of the hydraulic oil from being entrained in the reservoir tank.

However, when the cylinder device performs an extension operation at a high speed, there is a possibility that the flow of the hydraulic oil is not sufficiently rectified only by the conduit, and thus the hydraulic oil containing gas is entrained by the gas in the reservoir to generate an air charge, and the hydraulic oil containing gas enters the piston-side chamber through the suction passage, so that the cylinder device cannot generate a set damping force.

Accordingly, an object of the present invention is to provide a cylinder device capable of generating a set damping force even at the time of high-speed expansion and contraction.

Means for solving the problems

In order to achieve the above object, a cylinder device according to a solution of the present invention includes: a cylinder; a rod member inserted into the cylinder so as to be movable in the axial direction; a piston slidably inserted into the cylinder and coupled to one end of the rod, and dividing the inside of the cylinder into a rod-side chamber and a piston-side chamber filled with a liquid; a liquid storage tank for storing gas and liquid; a valve housing closing an end of the cylinder; a bottom cover disposed on the opposite side of the piston-side chamber of the valve housing; a liquid chamber formed between the valve housing and the bottom cover and communicated with the liquid storage tank; a discharge passage communicating the rod-side chamber with the liquid chamber without communicating with the liquid reservoir; a suction passage provided to the valve housing; a damping valve disposed in the discharge passage; and a check valve provided in the valve housing and setting the suction passage to a one-way passage that allows only the liquid to flow from the liquid reservoir to the piston-side chamber; wherein the discharge passage has an in-cap passage provided on the bottom cap, the in-cap passage having an open end facing the liquid chamber and being not branched.

In the cylinder device configured in this manner, since the liquid discharged from the inside of the cylinder and passing through the damper valve can be directly discharged into the liquid chamber provided on the opposite side of the piston-side chamber of the valve housing through the head inner passage provided to the bottom head without passing through the liquid reservoir and without branching, it is possible to forcibly inject the liquid without entrained gas into the piston-side chamber through the suction passage while increasing the pressure in the liquid chamber.

Further, the cylinder device may be configured such that the intake passage has a plurality of ports formed side by side in the circumferential direction on the valve housing, and the open end of the discharge passage opens at a position opposite to the axial direction of the valve housing within an imaginary circle of the smallest diameter of circles surrounding the entire ports. In the cylinder device configured in this way, since the distance between each port and the open end of the discharge passage is closer than in the case where the open end is arranged in a range not opposed to the imaginary circle, the liquid that passes through the discharge passage and enters the liquid chamber easily flows toward the port, the liquid can be easily delivered into the piston-side chamber through the suction passage, and the occurrence of insufficient suction of the liquid in the piston-side chamber can be effectively suppressed.

Further, the open end of the discharge passage in the cylinder device may face the opening of the inlet side of the suction passage of the valve housing. According to the cylinder device configured in this way, since the liquid discharged to the liquid chamber through the discharge passage flows toward the suction passage, the liquid can be more easily conveyed into the piston-side chamber through the suction passage, and the occurrence of insufficient suction of the liquid in the piston-side chamber can be effectively suppressed.

Further, the cylinder device may include: a first passage communicating the rod-side chamber and the piston-side chamber; a first switching valve disposed in the first passage; a second passage communicating the piston-side chamber with the reservoir; the second switch valve is arranged on the second channel; a supply passage for communicating the liquid storage tank with the rod-side chamber without passing through the discharge passage and the liquid chamber; and a pump provided in the supply passage and capable of sucking liquid from the liquid reservoir and discharging the liquid to the rod-side chamber. According to the cylinder device configured in this manner, since the pump directly sucks the hydraulic oil from the reservoir tank and supplies it to the rod-side chamber without passing through the discharge passage and the liquid chamber, the amount of hydraulic oil flowing into the liquid chamber through the discharge passage is not reduced by the driving of the pump, and it is possible to forcibly supply the liquid without entrained gas to the piston-side chamber while increasing the pressure in the liquid chamber, and the cylinder device can exert the set damping force even at the time of high-speed expansion and contraction.

Effects of the invention

According to the cylinder device of the present invention, a set damping force can be generated even at high-speed expansion and contraction.

Drawings

Fig. 1 is a longitudinal sectional view of a cylinder device in an embodiment of the present invention.

Fig. 2 is a diagram showing a state in which an actuator as a cylinder device according to an embodiment of the present invention is applied to a railway vehicle.

Fig. 3 is a diagram illustrating a position where an opening end of a discharge passage of a cylinder device according to an embodiment of the present invention is provided.

Fig. 4 is a diagram schematically showing a cylinder device in a first modification of the embodiment of the present invention.

Fig. 5 is a diagram schematically showing a cylinder device according to a second modification of the embodiment of the present invention.

Fig. 6 is a diagram schematically showing a cylinder device according to a third modification of the embodiment of the present invention.

Detailed Description

The present invention will be described based on embodiments shown in the drawings. As shown in fig. 1 and 2, the cylinder device C of the present embodiment is interposed between the bogie W and the vehicle body B of the railway vehicle, and is used as a vibration damping device for the vehicle body B for suppressing vibration of the vehicle body B in a horizontal lateral direction with respect to the vehicle traveling direction.

As shown in fig. 1, the cylinder device C includes: a cylinder 1; a rod member 2 inserted into the cylinder 1 so as to be movable in the axial direction; a piston 3 slidably inserted into the cylinder 1 and coupled to one end of the rod 2, and dividing the inside of the cylinder 1 into a rod-side chamber R1 filled with liquid and a piston-side chamber R2; a liquid storage tank T for storing gas and liquid; a valve housing 4 that closes the end of the cylinder 1 and partitions the piston-side chamber R2 and the liquid chamber L communicating with the liquid reservoir T; a discharge passage 5 communicating the rod-side chamber R1 and the liquid chamber L; a suction passage 6 provided in the valve housing 4; a damper valve 15 provided in the discharge passage 5; and a check valve 7 provided in the valve housing 4 and setting the suction passage 6 to a one-way passage that allows only the liquid to flow from the reservoir tank T to the piston-side chamber R2.

Hereinafter, each part of the cylinder device C will be described in detail. The cylinder 1 is cylindrical, and an annular rod guide 8 is fitted to the left end of the cylinder 1 in fig. 1, and a valve housing 4 is fitted to the right end of the cylinder 1 in fig. 1. A rod 2 is inserted through the inner periphery of the rod guide 8, and the rod is inserted into the cylinder 1 so as to be movable. And, the rod guide 8 guides the axial movement of the rod 2 with respect to the cylinder 1. One end of the rod 2 protrudes outside the cylinder 1, and the other end of the rod 2 is connected to a piston 3 slidably inserted into the cylinder 1. The left end of the cylinder 1 is closed by the rod guide 8 and the rod 2, and the right end of the cylinder 1 is closed by the valve housing 4.

An outer cylinder 9 is provided on the outer peripheral side of the cylinder 1 to cover the outer periphery of the cylinder 1. A rod guide 8 is fitted to the inner periphery of the outer cylinder 9 on the left end side in fig. 1, and a lock nut 10 having a threaded groove on the outer periphery is screwed to a threaded portion 9 a. Further, the right end of the outer cylinder 9 in fig. 1 is mounted with a bottom cover 11 for closing the right end of the outer cylinder 9 in fig. 1.

In this way, the rod guide 8, the cylinder 1, and the valve housing 4 fitted to the end of the cylinder 1 are sandwiched by the lock nut 10 and the bottom cover 11 mounted on the outer cylinder 9, and are fixed immovably with respect to the outer cylinder 9. As described above, the left end in fig. 1 of the cylinder 1 and the outer cylinder 9 is closed by the rod guide 8, the right end in fig. 1 of the outer cylinder 9 is closed by the bottom cover 11, and the annular gap between the cylinder 1 and the outer cylinder 9 is sealed.

In addition, the outer periphery of the rod 2 is sealed by an annular seal member 12 mounted on the rod guide 8, and the inside of the cylinder 1 is sealed. Further, the cylinder 1 is divided into a rod-side chamber R1 on the left side in fig. 1 and a piston-side chamber R2 on the right side in fig. 1 by a piston 3 slidably inserted inside. The rod-side chamber R1 and the piston-side chamber R2 are filled with hydraulic oil as liquid.

Next, the piston 3 is provided with a rectifying passage 13 which communicates the piston-side chamber R2 and the rod-side chamber R1 and which is provided with a check valve 13a at a middle portion thereof. The check valve 13a allows the hydraulic oil to flow only from the piston-side chamber R2 to the rod-side chamber R1, and the rectifying passage 13 is set to a one-way passage that allows the hydraulic oil to flow only from the piston-side chamber R2 to the rod-side chamber R1.

As described above, the valve housing 4 is fitted to the end of the cylinder 1 and closes the right end of the cylinder 1 in fig. 1. Specifically, the valve housing 4 includes: a disk-shaped body 4a sandwiched between the right end of the cylinder 1 in fig. 1 and the bottom cover 11; a fitting portion 4b that projects from the body portion 4a to the left in fig. 1 and is fitted to the inner periphery of the right end of the cylinder 1 in fig. 1; a recess 4c that opens from the right end of the main body 4a in fig. 1; and a recess 4d opened from the left end of the fitting portion 4b in fig. 1. The recess 4c communicates with an annular gap between the cylinder 1 and the outer cylinder 9 via a notch 4e, which is a passage described later, formed at the left end of the body portion 4a in fig. 1, and the recess 4d faces the piston-side chamber R2 and communicates with the piston-side chamber R2.

Further, the valve housing 4 has 6 ports 6a which communicate the recess 4c and the recess 4d through the body portion 4a to form the suction passage 6. The ports 6a are arranged at equal intervals on the same circumference around the axis of the valve housing 4, and communicate the piston side chamber R2 with the recess 4 c. The number of ports 6a may be set arbitrarily or may be singular. However, when the cross section of the port 6a is circular, if a plurality of ports 6a are provided, it is easy to secure the flow path area of the suction passage 6. The cross-sectional shape of the port 6a is not limited to a circle, but may be other shapes such as an arc or a rectangle. In addition, the larger the flow path area of the suction passage 6, the smoother the flow of the hydraulic oil from the reservoir tank T to the piston-side chamber R2, which is advantageous in that an insufficient suction does not occur when the piston-side chamber R2 is enlarged.

The bottom cover 11 is disposed on the opposite side of the piston-side chamber of the valve housing 4 and is attached to the outer cylinder 9 by welding to close the right end in fig. 1 of the outer cylinder 9, and the bottom cover 11 has a recess 11a at the left end in fig. 1 into which the right end in fig. 1 of the body portion 4a is fitted, and positions the valve housing 4 and the cylinder 1 fitted with the valve housing 4 in the radial direction. When the valve housing 4 is fitted with the bottom cover 11, the liquid chamber L is formed between the recess 4c of the valve housing 4 and the recess 11a of the bottom cover 11, i.e., on the opposite side of the piston-side chamber of the valve housing 4. Further, the depth of the recess 11a is shallower than the depth of the notch 4e of the valve housing 4, and even if the valve housing 4 is fitted in the recess 11a, communication between the liquid chamber L and the annular gap can be secured.

Further, the reservoir tank T is formed by an annular gap between the cylinder 1 and the outer cylinder 9. Further, the liquid chamber L formed by the recess 4c facing the opposite side of the piston-side chamber of the valve housing 4 is opened to the reservoir tank T with the slit 4e as a passage, and communicates with the piston-side chamber R2 through the suction passage 6. In addition, the passage that communicates the liquid reservoir tank T and the liquid chamber L may be formed by a portion other than the slit 4e, and may be provided in the bottom cover 11 instead of the valve housing 4.

The liquid storage tank T is filled with gas and hydraulic oil as in the cylinder 1, and the liquid chamber L is also filled with hydraulic oil. The liquid used in the cylinder device C may be a liquid other than hydraulic oil, such as water or an aqueous solution.

Further, the bottom cover 11 has: a fitting hole 11b opened from the left end in fig. 1, i.e., the end surface facing the reservoir tank T; and a cover inner passage 11c that opens from the fitting hole 11B, does not branch on the way, and opens to an end portion facing the liquid chamber L opposite to the recess 4c of the valve housing 4, and has a bracket 11d at a right end in fig. 1 that can be coupled to the vehicle body B of the railway vehicle. The cylinder device C is coupled to the vehicle body B and the bogie W of the railway vehicle by the brackets 2a and 11a, and can be mounted between the vehicle body B and the bogie W as shown in fig. 2.

The open end of the cap inner passage 11c facing the liquid chamber L formed by the recess 4c, that is, the open end of the discharge passage 5, opens at a position different from the open end facing the liquid chamber L, which is the slit 4e as a passage communicating the liquid chamber L to the liquid reservoir T. Further, as shown in fig. 3, the open end of the discharge passage 5 facing the liquid chamber L is opened at a position opposite to the axial direction of the valve housing 4 within an imaginary circle VC of the smallest diameter of the circles surrounding the entire port 6 a. That is, when the cylinder device C is viewed from the axial direction, the open end of the discharge passage 5 opens at a position opposite to the axial direction of the valve housing 4 within the range of the imaginary circle VC on the side of the liquid chamber L of the bottom cover 11. In the present embodiment, since all the ports 6a are arranged on the same circumference, the diameter of the virtual circle VC is a length obtained by adding the diameter of the ports 6a to the diameter of the same circle. For example, when the ports 6a are arranged in the range that is not uniform in the circumferential direction of the valve housing 4 even if they are not arranged at equal intervals on the same circumference, the diameter of the virtual circle VC is the length obtained by adding the diameter of the same circle to the diameter of the ports 6a, but in this case, the opening end of the discharge passage 5 may be provided at a position as opposed to the range where the ports 6a of the valve housing 4 are concentrated as much as possible. Further, the cover inner passage 11c is opened at a position axially opposed to any of the plurality of ports 6 a. The open end of the cover inner passage 11c may be branched to have a plurality of openings, and in this case, the open end may be opened at a position facing the range of the virtual circle VC, that is, at a position facing the port 6 a.

A check valve 7 is accommodated in the recess 4d of the valve housing 4, and the check valve 7 includes: an annular valve body 7a seatable off the bottom of the recess 4d to open and close the port 6 a; a ring-shaped spring support 7b fixed to the inner periphery of the fitting portion 4b, forming a side wall of the recess 4d of the valve housing 4; and a spring 7c installed between the valve body 7a and the spring support 7b to urge the valve body 7a toward the bottom. The spring 7c has a low spring constant, and pushes the valve body 7a with a very weak urging force, the valve body 7a closing all the ports 6a to shut off the suction passage 6 in a state of abutting against the bottom of the recess 4 d. In addition, the outer periphery of the valve body 7a is in sliding contact with the side wall forming the recess 4d of the valve housing 4, and is movable without being deviated in the radial direction when approaching in the axial direction away from the bottom of the valve body 7 a.

In the check valve 7, when the pressure in the liquid chamber L exceeds the pressure of the piston-side chamber R2 and the differential pressure therebetween reaches the valve-opening pressure set by the spring 7c, the spring 7c is compressed by receiving the pressure that presses the valve body 7a, and the suction passage 6 is opened. Further, when the pressure of the piston-side chamber R2 is higher than the pressure of the liquid chamber L, the check valve 7 remains seated in the valve housing 4, closing the outlet end of the port 6a to shut off the suction passage 6. Thus, the check valve 7 allows the hydraulic oil to flow only from the reservoir tank T to the piston-side chamber R2 and blocks the flow to the opposite side, and the suction passage 6 is set to a one-way passage that allows the hydraulic oil to flow only from the reservoir tank T to the piston-side chamber R2.

Next, the rod guide 8 has: a ring-shaped cover 8a fitted to the inner periphery of the outer cylinder 9 and into which the rod 2 is slidably inserted; an annular fitting portion 8b that protrudes from the right end of the cap portion 8a in fig. 1 to be fitted to the outer periphery of the cylinder 1; an annular recess 8c provided on the outer periphery of the left end of the lid portion 8a in fig. 1; a groove 8d located on the inner periphery of the lid portion 8a and formed from the right end to the middle in fig. 1; a fitting hole 8e located at the right end of the fitting portion 8b in fig. 1, facing the tank T, and axially facing the fitting hole 11b of the bottom cover 11; and a passage 8f communicating the groove 8d with the fitting hole 8 e.

Further, the rod guide 8 is accommodated in the outer cylinder 9 together with the cylinder 1 and the valve housing 4, and the bottom cover 11 is integrated with the outer cylinder 9 by welding and fixed inside the outer cylinder 9 together with the cylinder 1 and the valve housing 4 by a lock nut 10 screwed on the left end inner periphery in fig. 1 of the outer cylinder 9.

Further, on the inner periphery of the rod guide 8, an annular seal member 12 that is in sliding contact with the outer periphery of the rod 2 to seal between the rod 2 and the rod guide 8 is mounted to prevent liquid from leaking from the inside of the cylinder 1.

The left end of the pipe 14 housed in the tank T in fig. 1 is fitted into the fitting hole 8e of the rod guide 8, and the right end of the pipe 14 in fig. 1 is fitted into the fitting hole 11b of the bottom cover 11. In this way, the guide tube 14 is held by the rod guide 8 and the bottom cover 11 fixed to the outer cylinder 9, and therefore, even if vibration is input to the cylinder device C, it does not fall off.

The groove 8d provided in the lever guide 8 facing the lever-side chamber R1 communicates with the liquid chamber L, further, the liquid reservoir T through the slit 4e, through the passage 8f, in the guide tube 14, and the cover inner passage 11c provided in the bottom cover 11. Also, the discharge passage 5 is formed by these grooves 8d, the passage 8f, the inside of the conduit 14, and the cover inner passage 11c, and the hydraulic oil flowing from the rod-side chamber R1 to the reservoir tank T through the discharge passage 5 passes through the liquid chamber L to reach the reservoir tank T. In this way, the discharge passage 5 is formed by the cap inner passage 11c that is not branched from the inside and midway of the guide tube 14 held by the rod guide 8 and the bottom cap 11, and does not communicate with the liquid reservoir T midway, and therefore, the rectified liquid without entrained gas can be discharged into the liquid chamber L. In addition, instead of the duct 14, a tubular member may be provided on the inner or outer periphery of the outer cylinder 9, the tubular member forming an annular gap with the outer cylinder 9 as a part of the discharge passage 5.

Further, a damper valve 15 is provided midway in the passage 8f provided in the rod guide 8. In the present embodiment, the damping valve 15 is a variable relief valve that can adjust a valve opening pressure and open and close the discharge passage 5, and includes: the solenoid 15 a; a valve body 15b driven by the solenoid 15a and provided in the passage 8 f; a spring 15c that urges the valve body 15b in a valve closing direction; and a pilot passage 15d for causing the pressure in the rod side chamber R1 to act on the valve element 15b in the valve opening direction. The solenoid 15a applies a thrust force to the valve body 15b in a direction against the urging force of the spring 15 c. The valve element 15b is acted on by the thrust of the solenoid 15a and the pressure of the rod side chamber R1 in the valve opening direction, and acted on by the spring 15c in the valve closing direction. Since the magnitude of the thrust of the solenoid 15a can be adjusted by adjusting the amount of current applied to the solenoid 15a, the valve opening pressure at which the damping valve 15 opens the discharge passage 5 can be adjusted by adjusting the amount of current applied to the solenoid 15 a. In addition, the damping valve 15 may be a valve capable of adjusting its resistance to the flow of the hydraulic oil, other than the variable relief valve, and may be a valve that does not have an actuator such as a solenoid and provides a set resistance to the flow of the hydraulic oil if it is not necessary to adjust the damping force. Further, in the present embodiment, the damper valve 15 is provided in the pin guide 8, but may be provided in the bottom cover 11.

In the cylinder device C configured in this way, when the cylinder device C exhibits an extension action in which the rod 2 is withdrawn with respect to the cylinder 1 by an external input, the hydraulic oil in the rod-side chamber R1, which is contracted by the movement of the piston 3, cannot pass through the rectifying passage 13 because the check valve 13a is closed, and therefore, the hydraulic oil moves to the reservoir tank T through the discharge passage 5 and the liquid chamber L. As the check valve 7 opens, the hydraulic oil is supplied from the reservoir tank T through the suction passage 6 via the liquid chamber L to the piston-side chamber R2 enlarged by the expanding action of the cylinder device C. In this way, when the cylinder device C performs the extension operation, the pressure in the rod side chamber R1 rises due to the pressure loss when the hydraulic oil flows through the damping valve 15 provided in the discharge passage 5, and on the other hand, since the pressure in the piston side chamber R2 is almost the tank pressure, the cylinder device C generates the extension-side damping force that interferes with the extension operation. Further, since the pressure in the rod side chamber R1 can be adjusted by adjusting the valve opening pressure of the damper valve 15, the damping force on the expansion side generated by the cylinder device C can be adjusted by adjusting the amount of current applied to the solenoid 15a of the damper valve 15.

On the other hand, when the cylinder device C exhibits the contraction action, the hydraulic oil pushes open the check valve 13a and moves from the piston-side chamber R2, which is contracted by the movement of the piston 3, to the rod-side chamber R1, which is expanded, through the rectifying passage 13. Further, in the entire cylinder 1, the hydraulic oil of the volume portion of the rod member 2 entering the cylinder 1 becomes excessive, and the hydraulic oil of the excessive portion in the cylinder 1 moves from the cylinder 1 to the reservoir tank T through the damping valve 15 of the discharge passage 5 and the liquid chamber L. In this way, when the cylinder device C performs the contraction operation, the hydraulic oil flows through the damping valve 15 provided in the discharge passage 5, and the entire pressure in the cylinder 1 rises, so that the cylinder device C generates a compression-side damping force that interferes with the contraction operation. Since the pressure capacity of the cylinder 1 can be adjusted by adjusting the valve opening pressure of the damping valve 15, the compression-side damping force generated by the cylinder device C can be adjusted by adjusting the amount of current applied to the solenoid 15a of the damping valve 15.

As described above, when the cylinder device C expands and contracts, the hydraulic oil circulates unidirectionally in the reservoir tank T, the piston-side chamber R2, and the rod-side chamber R1, and flows through the damping valve 15. Therefore, the cylinder device C can function as a one-way type passive damper that generates a damping force both during an expansion operation and during a contraction operation, and can adjust the damping force by adjusting the valve opening pressure of the damping valve 15. Further, as described above, in the cylinder device C of the present embodiment, since the pressure receiving area on the rod side chamber R1 side of the piston 3 is set to be one-half of the pressure receiving area on the piston side chamber R2 side, the extension side damping force and the compression side damping force of the cylinder device C can be made equal if the valve opening pressures of the damping valves 15 are the same.

Also, in the cylinder device C of the present embodiment, the open end of the discharge passage 5 communicates with the liquid chamber L provided on the opposite side of the piston-side chamber of the valve housing 4, and the valve housing 4 is provided with the suction passage 6, and when the cylinder device C is extended, the hydraulic oil discharged from the cylinder 1 and passing through the damping valve 15 is discharged into the liquid chamber L. Further, since the open end of the discharge passage 5 facing the liquid chamber L is opened at a position different from the open end of the slit 4e on the side of the liquid chamber L, the opening 4e is a passage that communicates the liquid chamber L with the reservoir tank T, and therefore, the hydraulic oil flowing through the discharge passage 5 passes through the liquid chamber L, and is discharged into the reservoir tank T through the slit 4 e. In this manner, since the hydraulic oil that has passed through the discharge passage 5 passes through the liquid chamber L once, the pressure in the liquid chamber L tends to become higher than the reservoir tank T due to the inflow of the hydraulic oil, and at the same time, the hydraulic oil that has just passed through the discharge passage 5 without being in contact with the gas can be forcibly injected into the piston-side chamber R2 through the suction passage 6. Therefore, even if the cylinder device C extends at a high speed, the occurrence of insufficient intake of the hydraulic oil in the piston side chamber R2 and the intrusion of the hydraulic oil entrained with gas into the cylinder 1 can be suppressed, and therefore, the set damping force can be exerted.

As described above, the cylinder device C according to the present embodiment includes: a cylinder 1; a rod member 2 inserted into the cylinder 1 so as to be movable in the axial direction; a piston 3 slidably inserted into the cylinder 1 and coupled to one end of the rod 2, and dividing the inside of the cylinder 1 into a rod-side chamber R1 filled with hydraulic oil (liquid) and a piston-side chamber R2; a liquid storage tank T for storing gas and hydraulic oil (liquid); a valve housing 4 closing an end of the cylinder 1; a bottom cover 11 disposed on the opposite side of the piston-side chamber of the valve housing 4; a liquid chamber L formed between the valve housing 4 and the bottom cover 11 and communicating with the liquid reservoir tank T; a discharge passage 5 which communicates the rod-side chamber R1 with the liquid chamber L without communicating with the liquid reservoir T; a suction passage 6 provided in the valve housing 4; a damper valve 15 provided in the discharge passage 5; and a check valve 7 provided in the valve housing 4 and setting the suction passage 6 to a one-way passage that allows only the liquid to flow from the reservoir tank T to the piston-side chamber R2; here, the discharge passage 5 has a cover inner passage 11c provided in the bottom cover 11, the cover inner passage 11c having an open end facing the liquid chamber L and being not branched.

In the cylinder device C configured in this manner, as described above, since the hydraulic oil (liquid) discharged from the cylinder 1 and passing through the damper valve 15 without entrained gas can be discharged directly into the liquid chamber L provided on the opposite side of the piston-side chamber of the valve housing 4 after being rectified by the head inner passage 11C without branching, without passing through the reservoir tank T, it is possible to forcibly inject the hydraulic oil (liquid) without entrained gas into the piston-side chamber R2 through the suction passage 6 while increasing the pressure of the liquid chamber L.

As described above, according to the cylinder device C of the present embodiment, even when the expansion and contraction are performed at high speed, the occurrence of insufficient intake of the hydraulic oil in the piston side chamber R2 and the intrusion of the hydraulic oil (liquid) with entrained gas into the cylinder 1 can be suppressed, and therefore, the set damping force can be exerted.

In addition, the open end of the cap inner passage 11c, which is the open end of the discharge passage 5, to the liquid chamber L may also be opened at a position other than the position opposing the valve housing 4 in the range of the imaginary circle VC of the bottom cap 11, and furthermore, according to the shape and structure of the valve housing 4 and the shape and structure of the bottom cap 11, even in the case where the discharge passage 5 is connected to the liquid chamber L from the radial direction due to the arrangement relationship of the discharge passage 5, the pressure in the liquid chamber L is raised due to the inflow of the hydraulic oil flowing through the discharge passage 5, and the hydraulic oil that has just flowed through the discharge passage 5 without being in contact with the gas can be forcibly injected into the piston-side chamber R2 through the suction passage 6, and therefore, the effect of the present invention does not disappear. In contrast, in the cylinder device C of the present embodiment, the open end of the discharge passage 5, in this case, the open end of the head inner passage 11C facing the liquid chamber L is set at a position facing the axial direction of the valve housing 4 within an imaginary circle VC of the smallest diameter of circles surrounding the entire port 6 a. In the cylinder device C configured in this way, since the open end of the discharge passage 5 facing the liquid chamber L is set at a position opposite to the extent of the imaginary circle VC of the smallest diameter of the circle surrounding the entire port 6a, the hydraulic oil flowing through the discharge passage 5 into the liquid chamber L easily flows to the port 6a, the hydraulic oil is easily sent into the piston-side chamber R2 through the suction passage 6, and the occurrence of the suction shortage of the hydraulic oil in the piston-side chamber R2 can be effectively suppressed. In addition, even when the ports 6a are not arranged at equal intervals on the same circumference but are arranged in a range that is not uniform in the circumferential direction of the valve housing 4, the open end of the discharge passage 5 may be located within the range of the imaginary circle VC at a position facing the axial direction of the valve housing 4, and in this case, the open end of the discharge passage 5 may be provided so as to face a portion where the ports 6a of the valve housing 4 are concentrated as much as possible.

In the cylinder device C of the present embodiment, the open end of the discharge passage 5, in this case, the open end of the in-head passage 11C facing the liquid chamber L faces the opening on the inlet side of the intake passage 6 of the valve housing 4. In the present embodiment, specifically, the open end of the head inner passage 11c provided in the bottom head 11 faces the inlet end of any of the plurality of ports 6a forming the suction passage 6 provided in the valve housing 4, that is, the opposite side end of the piston-side chamber. According to the cylinder device C constructed in this way, since the hydraulic oil that passes through the discharge passage 5 and is discharged to the liquid chamber L flows toward the port 6a, it is easier to deliver the hydraulic oil into the piston-side chamber R2 through the suction passage 6, and it is possible to effectively suppress the occurrence of the insufficient suction of the hydraulic oil in the piston-side chamber R2.

Further, since the cylinder device C of the present embodiment is provided with the rectifying passage 13 that allows only the hydraulic oil (liquid) to flow from the piston-side chamber R2 to the rod-side chamber R1, the cylinder device C is set as a one-way type shock absorber. In the one-way type shock absorber, when the cylinder device C extends, it is necessary to supply the entire amount of the hydraulic oil in the volume-enlarged portion of the piston-side chamber R2 accompanying the movement of the piston 3 to the piston-side chamber R2. However, as described above, the cylinder device C according to the present embodiment can increase the pressure in the liquid chamber L during the extension operation, smoothly supply the hydraulic oil without entrained gas to the piston side chamber R2, and can exert the set damping force even if the device is set to the one-way type. Therefore, the cylinder device C of the present embodiment can improve the practicality of the one-way type damper.

Further, as described above, the cylinder device C is a one-way type shock absorber, but may be a two-way type shock absorber as long as it is a type that can discharge the hydraulic oil from the rod side chamber R1 to the liquid chamber L through the discharge passage 5 at the time of extension and supply the hydraulic oil that is insufficient in the piston side chamber R2 from the reservoir T. When the cylinder device is a bidirectional shock absorber, it may be configured as the cylinder device C1 of the first modification of the embodiment shown in fig. 4, for example. In fig. 4, the structure of the cylinder device C1 is schematically shown, but components denoted by the same reference numerals are the same as those of the cylinder device C of the embodiment. The cylinder device C1 is provided with, in addition to the cylinder device C of the embodiment, the rectifying passage 13 of the piston 3: a passage 16 which is provided in parallel with the discharge passage 5 and bypasses the damping valve 15; a check valve 17 provided in the passage 16 to allow only hydraulic oil to flow from the reservoir tank T toward the rod-side chamber R1; a passage 18 which is provided in parallel with the suction passage 6 and bypasses the check valve 7; and a compression-side damping valve 19 that is provided in the passage 18, allows only the flow of the hydraulic oil from the piston-side chamber R2 toward the tank T, and exerts resistance against the flow of the hydraulic oil therethrough.

The passage 16 communicates the reservoir tank T and the rod-side chamber R1 independently of the discharge passage 5, but may share a portion with the discharge passage 5, or may communicate the rod-side chamber R1 with the liquid chamber L. Further, the passage 18 communicates the piston side chamber R2 with the liquid chamber L independently of the suction passage 6, but may be a part common to the suction passage 6, or may communicate the piston side chamber R2 with the reservoir tank T.

In the cylinder device C1 configured in this way, during the expansion operation, the hydraulic oil in the rod-side chamber R1 that has contracted due to the movement of the piston 3 flows to the reservoir T through the damping valve 15 and the liquid chamber L, and the hydraulic oil is supplied from the reservoir T to the piston-side chamber R2 that has expanded due to the movement of the piston 3 via the liquid chamber L and the suction passage 6. When the cylinder device C1 extends, the hydraulic oil discharged from the discharge passage 5 is discharged to the liquid chamber L provided on the opposite side of the piston-side chamber of the valve housing 4, and therefore, the hydraulic oil without being entrained by the gas is forcibly injected into the piston-side chamber R2. Further, when the cylinder device C1 contracts, the hydraulic oil in the piston-side chamber R2, which has been reduced by the movement of the piston 3, flows to the reservoir tank T through the compression-side damping valve 19, and the hydraulic oil is supplied from the reservoir tank T to the rod-side chamber R1, which has been enlarged by the movement of the piston 3, through the passage 16. The hydraulic oil amount required in the rod-side chamber R1 when the cylinder device C1 contracts is an oil amount obtained by multiplying the movement amount of the piston 3 by a value obtained by subtracting the cross-sectional area of the rod 2 from the cross-sectional area of the piston 3. In the cylinder device C1 of the present embodiment, since the sectional area of the rod 2 is half of the sectional area of the piston 3, the amount of hydraulic oil required in the rod side chamber R1 when the cylinder device C1 performs the contraction operation is half of the amount of hydraulic oil required in the piston side chamber R2 when the cylinder device C1 performs the expansion operation. Therefore, when the cylinder device C1 performs the contraction operation, there is no problem even if the outlet end of the passage 18 provided with the compression-side damping valve 19 is not provided in the vicinity of the inlet of the check valve 17. Further, it is needless to say that the outlet end of the passage 18 may be provided at the position closest to or opposite to the inlet of the port of the check valve 17 provided in the member in which the check valve 17 is provided, and the hydraulic oil may be injected into the rod-side chamber R1. In this way, even in the case of the cylinder device C1 of the bidirectional type, since the hydraulic oil is discharged to the liquid chamber L provided on the opposite side of the piston-side chamber of the valve housing 4 during the expansion operation, the pressure in the liquid chamber L can be increased and the hydraulic oil without entrained gas can be forcibly supplied to the piston-side chamber R2, and therefore, even if the cylinder device C1 expands and contracts at high speed, the set damping force can be exerted.

Further, when the passage 18 communicates with the liquid chamber L, the hydraulic oil flows into the liquid chamber L from the piston-side chamber R2 when the cylinder device C1 performs the contraction operation, and the pressure in the liquid chamber L tends to increase, so that the hydraulic oil is rapidly supplied to the piston-side chamber R2 when the cylinder device C1 switches to the extension operation, and therefore the damping force also rapidly increases when the cylinder device C1 switches from the contraction operation to the extension operation.

Further, when the cylinder device C2 is a semi-active damper, it may be configured as the cylinder device C2 according to the second modification of the embodiment shown in fig. 5. In fig. 5, the structure of the cylinder device C2 is schematically shown, but components denoted by the same reference numerals are the same as those of the cylinder device C of the embodiment.

The cylinder device C2 includes, in addition to the structure of the cylinder device C according to the embodiment: a first passage 20 communicating the rod-side chamber R1 with the piston-side chamber R2; a first on-off valve 21 provided midway in the first passage 20; a second passage 22 that communicates the piston-side chamber R2 with the reservoir tank T; and a second on-off valve 23 provided midway in the second passage 22.

The first passage 20 is formed by passages provided inside the rod guide 8, the bottom cover 11, and the valve housing 4, and the conduit 24 bridged between the rod guide 8 and the bottom cover 11, and communicates the rod-side chamber R1 with the piston-side chamber R2.

The first on-off valve 21 provided in the first passage 20 is an electromagnetic on-off valve that adopts a communication position to open the first passage 20 when energized and adopts a blocking position to block the first passage 20 when de-energized, and is provided in the rod guide 8. The first on-off valve 21 may be provided in the bottom cover 11.

The second passage 22 shares a part of the passage with the discharge passage 5 and the first passage 20, and communicates the piston-side chamber R2 with the reservoir tank T through the inside of the conduits 14, 24. The second passage 22 may be provided separately from the discharge passage 5 and the first passage 20, but the number of components and the number of processing steps can be reduced by sharing a part of the passage with the discharge passage 5 and the first passage 20.

The second on-off valve 23 provided in the second passage 22 is an electromagnetic on-off valve that adopts a communication position for opening the second passage 22 when energized and adopts a blocking position for blocking the second passage 22 when de-energized, and is provided in the rod guide 8. The second on-off valve 23 may be provided in the bottom cover 11.

In the cylinder device C2 configured in this way, when the first switching valve 21 is in the communication position and the second switching valve 23 is in the shutoff position, the rod-side chamber R1 and the piston-side chamber R2 are in the communication state via the first passage 20, and the communication between the piston-side chamber R2 and the reservoir tank T via the second passage 22 is shut off. In this state, when the cylinder device C2 exhibits an extension action in which the rod 2 retreats relative to the cylinder 1 by an external input, the hydraulic oil moves from the contracted rod-side chamber R1 to the expanded piston-side chamber R2 through the first passage 20. Further, in the entire cylinder 1, the volume portion of the rod member 2 withdrawn from the cylinder 1 is short of the hydraulic oil, and the short portion of the hydraulic oil is opened by the check valve 7 to move from the reservoir tank T to the piston-side chamber R2 via the liquid chamber L and the suction passage 6. In this way, in the state where the first on-off valve 21 is in the on position and the second on-off valve 23 is in the off position, even if the cylinder device C2 performs the extension operation, the hydraulic oil does not flow through the damping valve 15 provided in the discharge passage 5, and since the rod side chamber R1 and the piston side chamber R2 are almost at the tank pressure, the cylinder device C2 does not generate the extension-side damping force that hinders the extension operation.

On the other hand, in a state where the first switching valve 21 is in the on position and the second switching valve 23 is in the off position, when the cylinder device C2 exhibits the contraction operation, the hydraulic oil moves from the reduced piston-side chamber R2 to the enlarged rod-side chamber R1 after passing through the first passage 20. Further, in the entire cylinder 1, the hydraulic oil in the volume portion of the rod member 2 entering the cylinder 1 becomes excessive, and since the second passage 22 is cut off, the hydraulic oil in the excessive portion in the cylinder 1 moves from the cylinder 1 to the reservoir tank T through the damping valve 15 and the liquid chamber L of the discharge passage 5. In this way, when the cylinder device C2 contracts in a state where the first on-off valve 21 is in the on position and the second on-off valve 23 is in the off position, the hydraulic oil flows through the damping valve 15 provided in the discharge passage 5, and the entire pressure in the cylinder 1 rises, so that the cylinder device C2 generates a compression-side damping force that interferes with the contraction operation. Since the magnitude of the pressure in the cylinder 1 can be adjusted by adjusting the valve opening pressure of the orifice valve 15, the compression-side damping force generated by the cylinder device C2 can be adjusted by adjusting the amount of current applied to the orifice valve 15.

Further, in the cylinder device C2, when the first switching valve 21 is in the cut-off position and the second switching valve 23 is in the communication position, the communication between the rod-side chamber R1 and the piston-side chamber R2 via the first passage 20 is cut off, and the piston-side chamber R2 and the reservoir tank T are communicated via the second passage 22. In this state, when the cylinder device C2 exhibits an expansion operation in which the rod 2 is retracted with respect to the cylinder 1 by an external input, the first passage 20 is cut off, and therefore, the hydraulic oil flows from the reduced rod-side chamber R1 through the damping valve 15 and the liquid chamber L of the discharge passage 5 to the reservoir T. The hydraulic oil is supplied from the reservoir tank T to the piston-side chamber R2 that is expanded by the expansion operation of the cylinder device C2 after passing through the second passage 22. In this way, when the cylinder device C2 performs an expansion operation in a state where the first on-off valve 21 is in the shutoff position and the second on-off valve 23 is in the on position, the hydraulic oil flows through the damping valve 15 provided in the discharge passage 5, and the pressure in the rod side chamber R1 rises, while the pressure in the piston side chamber R2 is almost the tank pressure, and therefore the cylinder device C generates an expansion-side damping force that interferes with the expansion operation. Since the pressure in the rod side chamber R1 can be adjusted by adjusting the valve opening pressure of the damping valve 15, the expansion side damping force generated by the cylinder device C2 can be adjusted by adjusting the amount of current applied to the damping valve 15.

On the other hand, in a state where the first switching valve 21 is in the shutoff position and the second switching valve 23 is in the communication position, when the cylinder device C2 exhibits the contraction action, the hydraulic oil pushes open the check valve 13a and moves from the reduced piston-side chamber R2 through the rectifying passage 13 to the enlarged rod-side chamber R1. Further, in the entire cylinder 1, the hydraulic oil of the volume portion of the rod member 2 entering the cylinder 1 becomes excessive, and the excessive hydraulic oil in the cylinder 1 moves from the cylinder 1 to the reservoir tank T through the second passage 22. In this way, in the state where the first on-off valve 21 is in the shutoff position and the second on-off valve 23 is in the on position, even if the cylinder device C2 performs the contraction operation, the hydraulic oil does not flow through the damping valve 15 provided in the discharge passage 5, and the rod side chamber R1 and the piston side chamber R2 are almost at the tank pressure, so the cylinder device C2 does not generate the compression side damping force that hinders the contraction operation.

As described above, in the cylinder device C2 of the present embodiment, the pressure receiving area on the rod-side chamber R1 side of the piston 3 is set to be one-half of the pressure receiving area on the piston-side chamber R2 side. Therefore, when the valve opening pressure of the damper valve 15 is made the same, the damping force on the expansion side and the damping force on the compression side of the cylinder device C2 become equal. Therefore, if the pressure receiving area on the rod side chamber R1 side of the piston 3 is set to one-half of the pressure receiving area on the piston side chamber R2 side, the damping force of the cylinder device C2 can be easily controlled.

As described above, when the first switching valve 21 is in the on position and the second switching valve 23 is in the off position, the cylinder device C2 generates the damping force only during the contraction operation, and does not generate the damping force during the expansion operation. Further, when the first switching valve 21 is in the shutoff position and the second switching valve 23 is in the communication position, the cylinder device C2 generates the damping force only during the expansion operation, and does not generate the damping force during the contraction operation.

In the state shown in fig. 2 in which the cylinder device C2 is mounted on the railway vehicle, the cylinder device C2 exhibits a contracting action when the vehicle body B moves to the right with respect to the bogie W, and the cylinder device C2 exhibits an expanding action when the vehicle body B moves to the left with respect to the bogie W. In this case, although the cylinder device C2 suppresses the rightward movement of the vehicle body B by the compression-side damping force, when the vehicle body B and the bogie W move rightward and the moving speed of the bogie W is relatively slow, the cylinder device C performs a contraction operation to generate the compression-side damping force, thereby suppressing the vibration of the vehicle body B. However, when the vehicle body B and the bogie W move rightward and the moving speed of the bogie W is relatively high, the cylinder device C2 exhibits the expansion operation without performing the contraction operation. Here, when the cylinder device C2 generates an extension-side damping force, the extension operation of the cylinder device C2 is suppressed, and therefore, the movement of the bogie W in the right direction is transmitted to the vehicle body B. However, in the cylinder device C2 of the present embodiment, since it can function as a semi-active damper having a one-sided effect, it is possible to control so that only the damping force on the compression side is generated when the vehicle body B and the bogie W move to the right and the moving speed of the bogie W is relatively high, and it is possible to prevent the vibration of the vehicle body B from being promoted. When the vehicle body B and the carriage W move leftward and the moving speed of the carriage W is relatively high, it is only necessary to control so that only the damping force on the expansion side of the cylinder device C2 is generated. In this way, when the direction in which the cylinder device C2 generates damping force is a direction in which the vibration of the vehicle body B is intensified by the vibration of the bogie W of the railway vehicle, the cylinder device C2 can be caused to function as a shock absorber having a one-sided effect so as not to generate force in such a direction. Therefore, this cylinder device C2 can easily realize semi-active control according to the Carnop (Carnop) theory, and thus can function as a semi-active shock absorber.

Next, when both the first on-off valve 21 and the second on-off valve 23 are set to the off positions, the circuit structure of the cylinder device C2 is identical in appearance to the circuit structure of the cylinder device C of the embodiment that does not include the first passage 20, the first on-off valve 21, the second passage 22, and the second on-off valve 23. Therefore, in this case, the cylinder device C2 functions as a one-way type shock absorber that generates a damping force during both the expansion operation and the contraction operation because the hydraulic oil always passes through the damping valve 15 during the expansion and contraction operation.

Further, in the cylinder device C2, when both the first switching valve 21 and the second switching valve 23 are in the communication position, the rod-side chamber R1 and the piston-side chamber R2 communicate via the first passage 20, and the piston-side chamber R2 and the reservoir tank T communicate via the second passage 22. That is, when the cylinder device C2 is in this state, the rod-side chamber R1 and the piston-side chamber R2 are always in communication with the reservoir T via the first passage 20 and the second passage 22, and therefore, the reservoir pressure is present in the cylinder 1 regardless of whether the cylinder device C2 performs the expansion operation or the contraction operation, and the cylinder device C2 is in the unloaded state in which the damping force is not exerted.

In the cylinder device C2 configured in this way, the hydraulic oil is discharged from the rod-side chamber R1 to the liquid chamber L formed between the valve housing 4 and the bottom cover 11 via the discharge passage 5 so as to generate the damping force during the expansion operation. As described above, the cylinder device C2 can forcibly supply the pressure oil without gas entrainment to the piston-side chamber R2 while increasing the pressure in the liquid chamber L, as in the cylinder device C of the embodiment, and therefore can exert a set damping force even when expanding and contracting at a high speed.

As in the cylinder device C3 of the third modification of the embodiment shown in fig. 6, the pump P and the motor M may be added to the structure of the cylinder device C2, and the cylinder device C3 may function as an actuator.

Specifically, the cylinder device C3 according to the third modification includes, in addition to the structure of the cylinder device C2: a supply passage 25 that communicates the rod-side chamber R1 with the reservoir tank T without passing through the discharge passage 5 and the liquid chamber L; a pump P provided in the bottom cover 11 and capable of supplying hydraulic oil from the reservoir tank T to the rod-side chamber R1 through the supply passage 25; a motor M mounted to the bottom cover 11 and driving the pump P; and a check valve 26 provided midway in the supply passage 25 between the pump P and the rod-side chamber R1 and allowing only the hydraulic oil to flow from the pump P to the rod-side chamber R1.

The supply passage 25 is formed by a passage provided inside the rod guide 8 and the bottom cover 11 and a conduit 27 bridged between the rod guide 8 and the bottom cover 11, and communicates the rod-side chamber R1 with the tank T.

The pump P is provided in the bottom cover 11, and in the present embodiment, is a gear pump provided in the middle of the supply passage 25. The motor M is attached to the bottom cover 11 and supplies power to the drive shaft of the pump P. When the pump P is driven by the motor M, hydraulic oil is sucked from the reservoir tank T and supplied to the rod-side chamber R1. The pump P may be a pump other than a gear pump. Further, the motor M may be provided with a speed reducer, and in this case, an output shaft of the speed reducer may be connected to the pump P. Further, the pump P and the motor M may be provided to the rod guide 8.

In the cylinder device C3 configured in this way, when the first on-off valve 21 is brought into the on position and the second on-off valve 23 is brought into the off position while the pump P is driven by the motor M, the rod-side chamber R1 and the piston-side chamber R2 are brought into the on state by the first passage 20, and hydraulic oil is supplied from the pump P to both. By the supply of the hydraulic oil, the sum of the volumes of the rod-side chamber R1 and the piston-side chamber R2 is increased, and the rod 2 is pushed out from the cylinder 1 to the left in fig. 6, so that the cylinder device C3 exhibits an extending action. When the pressures in the rod side chamber R1 and the piston side chamber R2 exceed the valve opening pressure of the damper valve 15, the damper valve 15 opens, and the hydraulic oil is discharged to the reservoir T through the discharge passage 5 and the liquid chamber L. Therefore, the pressures in the rod side chamber R1 and the piston side chamber R2 are controlled to be equal to the valve opening pressure of the damper valve 15. Therefore, the cylinder device C3 generates an extension-direction thrust equal to a value obtained by multiplying the difference in pressure receiving area between the piston-side chamber R2 and the rod-side chamber R1 of the piston 3 by the valve opening pressure of the damping valve 15. Further, the thrust force generated by the cylinder device C3 is adjusted by adjusting the amount of current applied to the damping valve 15.

On the other hand, in the cylinder device C3, when the pump P is driven by the motor M and the first switching valve 21 is set to the shutoff position and the second switching valve 23 is set to the communication position, the hydraulic oil is supplied only to the rod side chamber R1 and the rod side chamber R1 is expanded, and conversely, the hydraulic oil is discharged from the contracted piston side chamber R2 to the reservoir tank T through the second passage 22 which is set in the communication state. Then, the piston 3 is pushed rightward in fig. 6, and the cylinder device C3 exhibits a contracting action. In this case, the pressure of the piston-side chamber R2 is the tank pressure, and the pressure of the rod-side chamber R1 is controlled to a pressure equal to the valve opening pressure of the damper valve 15. Therefore, the cylinder device C3 generates a thrust force in the contraction direction, which is equal to a value obtained by multiplying the pressure receiving area on the rod side chamber R1 side in the piston 3 by the valve opening pressure of the damper valve 15. Further, the thrust force generated by the cylinder device C3 is adjusted by adjusting the amount of current applied to the damping valve 15.

In this way, when one of the first on-off valve 21 and the second on-off valve 23 is set to the on position and the other of the first on-off valve 21 and the second on-off valve 23 is set to the off position in accordance with the direction of the thrust to be output from the cylinder device C3 while the pump P is driven, the cylinder device C3 functions as an actuator. In the present embodiment, the damping valve 15 is a variable relief valve, and therefore is also used for controlling the thrust force when the cylinder device C3 functions as an actuator.

Further, when the pump P is stopped, the cylinder device C3 includes the rectifying passage 13, the intake passage 6, the first passage 20, the second passage 22, the discharge passage 5, the first on-off valve 21 provided in the first passage 20, the second on-off valve 23 provided in the second passage 22, and the damping valve 15 provided in the discharge passage 5, as in the cylinder device C2, and therefore, the switching of the opening and closing of the first on-off valve 21 and the second on-off valve 23 can function as a semi-active damper or a passive damper, and can be in an unloaded state. In the unloaded state, cylinder device C3 is in a state in which cylinder device C2 does not expand or contract even when pump P is driven, and in which damping force is not generated against vibration due to external force.

In the cylinder device C3 configured in this way, when functioning as a shock absorber, the hydraulic oil is discharged from the rod-side chamber R1 to the liquid chamber L provided on the opposite side of the piston-side chamber of the valve housing 4 via the discharge passage 5 so as to generate a damping force during the extension operation. In the cylinder device C3, since the pump P directly sucks the hydraulic oil from the reservoir tank T and supplies it to the rod-side chamber R1 without passing through the discharge passage 5 and the liquid chamber L, the amount of hydraulic oil flowing into the liquid chamber L through the discharge passage 5 is not reduced by the driving of the pump P. In this way, even in the cylinder device C3 in which the pump P is mounted to generate thrust, the pressure in the liquid chamber L can be increased and the hydraulic oil without entrained gas can be forcibly supplied to the piston-side chamber R2, as in the cylinder device C of the embodiment, and therefore, a set damping force can be exerted even when the piston expands and contracts at high speed.

The shapes and structures of the rod guide 8, the valve housing 4, and the bottom cover 11 in the cylinder devices C, C1, C2, and C3 may be changed arbitrarily, and each may be formed of a plurality of members. Further, the cylinder devices C, C1, C2, and C3 can be used for various purposes such as suppressing vibration of a building and a machine, suppressing vibration of a vehicle, and the like, in addition to suppressing vibration of a railway vehicle.

While the preferred embodiments of the present invention have been illustrated and described in detail, modifications, variations and changes may be made without departing from the scope of the claims.

Description of the symbols

1 cylinder

2 Bar

3 piston

4 valve housing

4e incision (channel)

5 discharge channel

6 suction channel

6a port

7 check valve

8 rod guide

11 bottom cover

11c cover inner channel

13 rectifying channel

15 damping valve

20 first channel

21 first on-off valve

22 second channel

23 second on-off valve

25 feed channel

C, C1, C2, C3 cylinder device

L liquid chamber

P pump

R1 rod side chamber

R2 piston side Chamber

T liquid storage tank

VC imaginary circle

Claims (4)

1. A cylinder device is characterized by comprising:

a cylinder;

a rod member inserted into the cylinder so as to be movable in an axial direction;

a piston slidably inserted into the cylinder and coupled to one end of the rod, and dividing the inside of the cylinder into a rod-side chamber and a piston-side chamber filled with a liquid;

a liquid storage tank for storing gas and liquid;

a valve housing closing an end of the cylinder;

a bottom cover disposed on the opposite side of the piston-side chamber of the valve housing;

a liquid chamber formed between the valve housing and the bottom cap and communicating with the liquid reservoir;

a discharge passage that communicates the rod-side chamber with the liquid chamber without communicating with the liquid reservoir;

a suction passage provided to the valve housing;

a damping valve disposed in the discharge passage;

and a check valve provided to the valve housing and setting the suction passage to a one-way passage that allows only a flow of liquid from the liquid storage tank to the piston-side chamber;

wherein the discharge passage has a cover inner passage provided on the bottom cover, the cover inner passage having an open end facing the liquid chamber and being not branched.

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

the suction passage has a plurality of ports formed side by side in a circumferential direction on the valve housing,

and the open end of the discharge passage opens at a position opposite to the axial direction of the valve housing within an imaginary circle of a smallest diameter in a circle surrounding the entire port.

3. The cylinder device according to claim 2, wherein:

the open end of the discharge passage faces an opening of an inlet side of the suction passage of the valve housing.

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

a first passage communicating the rod-side chamber and the piston-side chamber;

a first switching valve disposed in the first passage;

a second passage communicating the piston-side chamber with the liquid reservoir;

a second switching valve disposed in the second passage;

a supply passage that communicates the liquid reservoir and the rod-side chamber without passing through the discharge passage and the liquid chamber;

and a pump provided in the supply passage and capable of supplying the liquid from the liquid reservoir to the rod-side chamber.

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