Cylinder device

Abstract

The present application provides a cylinder device capable of generating a set damping force even when being stretched or contracted at high speed. The cylinder device comprises: a cylinder; a piston slidably inserted into the cylinder and connected to one end of a rod, and dividing the cylinder into a rod-side chamber filled with liquid and a piston-side chamber; a liquid reservoir 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 and the liquid chamber without communicating with the liquid reservoir; a suction passage provided in the valve housing; a damping valve provided in the discharge passage; and a check valve provided in the valve housing and setting the suction passage to allow liquid to flow from the liquid reservoir to the piston-side chamber only; wherein the discharge passage has a cover-in passage that is not branched.

Description

TECHNICAL FIELD

[0001] The present application relates to a cylinder device. BACKGROUND

[0002] Conventionally, as such a cylinder device, for example, a damper for mounting between a car body and a bogie of a railway vehicle and suppressing vibration of the car body in the left-right direction with respect to the vehicle traveling direction is known.

[0003] Specifically, such a cylinder device is provided with 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 member, and dividing the cylinder into a rod member side chamber filled with hydraulic oil and a piston side chamber, an outer tube provided to the outer periphery of the cylinder, a reservoir formed by an annular gap between the cylinder and the outer tube, a discharge passage communicating the rod member side chamber and the reservoir, a suction passage communicating the reservoir and the piston side chamber, a damping valve provided to the discharge passage, a check valve provided to the suction passage allowing hydraulic oil to flow only from the reservoir to the piston side chamber, and a straightening passage provided to the piston allowing hydraulic oil to flow only from the piston side chamber to the rod member side chamber, and is a one-way passive damper.

[0004] Further, the discharge passage is formed by a passage provided to a rod member guide fitted to the end of the rod member chamber side of the cylinder and a conduit installed on the rod member guide and housed in the reservoir.

[0005] Patent Literature 1 Japanese Patent Application Publication No. 2014-149003 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In the cylinder device configured in this way, when the cylinder device performs an extension operation, hydraulic oil is discharged from the rod member side chamber which is compressed to the reservoir through the discharge passage, and the hydraulic oil of the volume portion of the rod member which is withdrawn from the cylinder is replenished to the enlarged piston side chamber from the reservoir through the suction passage.

[0008] As described above, the discharge passage is formed by the conduit housed in the reservoir, and the flow of the hydraulic oil flowing through the damping valve with an increased flow rate is straightened by the conduit, the hydraulic oil is discharged into the reservoir to prevent gas entrainment of the hydraulic oil in the reservoir.

[0009] However, when the cylinder device performs an extension operation at high speed, it is possible that straightening of the flow of the hydraulic oil by the conduit alone is not sufficient, and gas in the reservoir is entrained to generate air charge, the hydraulic oil containing the gas enters the piston side chamber through the suction passage, and thus the cylinder device cannot generate a set damping force.

[0010] Therefore, the object of the present invention is to provide a cylinder device that can generate a set damping force even when extending and retracting at high speed.

[0011] Solution for solving the problem

[0012] To achieve the aforementioned objective, the cylinder device in the solution of the present invention comprises: a cylinder; a rod movably inserted into the cylinder along an axial direction; a piston slidably inserted into the cylinder and connected to one end of the rod, dividing the cylinder into a rod-side chamber filled with liquid and a piston-side chamber; a reservoir storing gas and liquid; a valve housing that closes the 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 communicating with the reservoir; a discharge passage communicating with the rod-side chamber and the liquid chamber but not with the reservoir; an intake passage disposed in the valve housing; a damping valve disposed in the discharge passage; and a check valve disposed in the valve housing and configured to allow only liquid to flow from the reservoir to the piston-side chamber; wherein the discharge passage has an inner cover passage disposed on the bottom cover, the inner cover passage having an open end facing the liquid chamber and not branching.

[0013] In a cylinder device constructed in this way, since the liquid discharged from the cylinder and passing through the damping valve can be discharged directly into the liquid chamber opposite the piston side chamber of the valve housing through an unbranched cover passage without passing through the reservoir, liquid without entrained gas can be forcibly injected into the piston side chamber through the suction passage while increasing the pressure in the liquid chamber.

[0014] Alternatively, the cylinder assembly can be configured such that the intake channel has multiple ports arranged circumferentially side-by-side on the valve housing, and the opening end of the discharge channel opens within an imaginary circle of minimum diameter surrounding the entire port, at a position axially opposite to the valve housing. In this configuration, since the distance between each port and the opening end of the discharge channel is closer than if the opening end were positioned outside the imaginary circle, liquid flowing through the discharge channel and into the liquid chamber easily flows to the ports. This facilitates easy delivery of liquid through the intake channel to the piston-side chamber and effectively suppresses insufficient liquid intake in the piston-side chamber.

[0015] Furthermore, the opening end of the discharge passage in the cylinder assembly can be directly opposite the opening on the inlet side of the suction passage of the valve housing. According to the cylinder assembly configured in this way, since the liquid discharged to the liquid chamber through the discharge passage flows to the suction passage, it is easier to deliver liquid to the piston-side chamber through the suction passage, and the occurrence of insufficient liquid intake in the piston-side chamber can be effectively suppressed.

[0016] Furthermore, the cylinder device may also include: a first channel connecting the rod-side chamber and the piston-side chamber; a first switching valve disposed in the first channel; a second channel connecting the piston-side chamber and the reservoir; a second switching valve disposed in the second channel; a supply channel connecting the reservoir and the rod-side chamber without passing through a discharge channel and a liquid chamber; and a pump disposed in the supply channel and capable of drawing liquid from the reservoir and discharging it to the rod-side chamber. According to the cylinder device configured in this way, since the pump draws hydraulic oil directly from the reservoir and supplies it to the rod-side chamber without passing through a discharge channel and a liquid chamber, the amount of hydraulic oil flowing into the liquid chamber through the discharge channel is not reduced due to the pump's operation. This allows for the forced supply of liquid without entrained gas to the piston-side chamber while increasing the pressure in the liquid chamber, enabling the cylinder device to exert the set damping force even during high-speed extension and retraction.

[0017] Invention Effects

[0018] The cylinder device according to the present invention can generate a set damping force even during high-speed extension and retraction. Attached Figure Description

[0019] Figure 1 This is a longitudinal cross-sectional view of a cylinder device according to one embodiment of the present invention.

[0020] Figure 2 This is a diagram showing the state in which the actuator of the cylinder device, as an embodiment of the present invention, is applied to a railway vehicle.

[0021] Figure 3 This figure illustrates the location of the opening end of the discharge passage of a cylinder device according to an embodiment of the present invention.

[0022] Figure 4 This is a diagram illustrating, in principle, a cylinder device in a first variation of an embodiment of the present invention.

[0023] Figure 5 This is a diagram illustrating, in principle, a cylinder device in a second variation of an embodiment of the present invention.

[0024] Figure 6 This is a diagram illustrating, in principle, the cylinder device in a third variation of an embodiment of the present invention. Detailed Implementation

[0025] The present invention will now be described based on the embodiments shown in the figures. Figure 1 and Figure 2 As shown, the cylinder device C of this embodiment is inserted between the trolley W and the body B of the railway vehicle, and is used as a shock absorber for the body B to suppress the horizontal vibration of the body B relative to the direction of vehicle travel.

[0026] like Figure 1 As shown, the cylinder device C includes: a cylinder 1; a rod 2 movably inserted into the cylinder 1 along the axial direction; a piston 3 slidably inserted into the cylinder 1 and connected to one end of the rod 2, dividing the cylinder 1 into a rod-side chamber R1 filled with liquid and a piston-side chamber R2; a reservoir T storing gas and liquid; a valve housing 4 that closes the end of the cylinder 1 while separating the piston-side chamber R2 and a liquid chamber L communicating with the reservoir T; a discharge passage 5 communicating with the rod-side chamber R1 and the liquid chamber L; a suction passage 6 provided in the valve housing 4; a damping valve 15 provided in the discharge passage 5; and a check valve 7 provided in the valve housing 4 and configured to allow liquid to flow only from the reservoir T to the piston-side chamber R2 as a one-way passage.

[0027] The following will provide a detailed description of each part of the cylinder assembly C. Cylinder 1 is cylindrical. In cylinder 1... Figure 1 The left end of the cylinder 1 is fitted with a ring-shaped rod guide 8. Figure 1 The right end of the cylinder 1 is fitted with a valve housing 4. A rod 2 is inserted through the inner circumference of the rod guide 8, and this rod can be freely inserted into the cylinder 1. Furthermore, the rod guide 8 guides the rod 2 to move axially relative to the cylinder 1. One end of the rod 2 protrudes outward from the cylinder 1, and the other end of the rod 2 is connected to a piston 3 that can be freely 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.

[0028] An outer cylinder 9 is provided on the outer periphery of the cylinder 1 to cover the outer periphery of the cylinder 1. Figure 1 A rod guide 8 is fitted into the inner circumference of the left end side of the outer cylinder 9, and a threaded portion 9a is formed therein, into which a locking nut 10 with a threaded groove on the outer circumference is screwed. Furthermore, the outer cylinder 9... Figure 1 A bottom cover 11 is installed at the right end of the inner cylinder 9. This bottom cover is used to close the outer cylinder 9. Figure 1 The right end of the middle.

[0029] Thus, the rod guide 8, the cylinder 1, and the valve housing 4, which engages with the end of the cylinder 1, are clamped by the locking nut 10 and the bottom cover 11 mounted on the outer cylinder 9, and are fixed immovably relative to the outer cylinder 9. As described above, the cylinder 1 and the outer cylinder 9... Figure 1 The left end of the inner cylinder is closed by the rod guide 8, and the outer cylinder 9 Figure 1 The right end of the cylinder is closed by the bottom cover 11, which also seals the annular gap between the cylinder 1 and the outer cylinder 9.

[0030] Furthermore, the outer periphery of the rod 2 is sealed by an annular sealing member 12 installed on the rod guide 8, and the cylinder 1 is also sealed. Further, the cylinder 1 is divided by a piston 3 that can be slidably inserted into the inner side.Figure 1 The left side chamber of the rod and Figure 1 The piston-side chamber R2 is located on the right side. Furthermore, both the rod-side chamber R1 and the piston-side chamber R2 are filled with hydraulic oil as a fluid.

[0031] Next, a flow-rectifying channel 13 is provided on the piston 3, which connects the piston-side chamber R2 and the rod-side chamber R1, and includes a check valve 13a in the middle. The check valve 13a only allows hydraulic oil to flow from the piston-side chamber R2 to the rod-side chamber R1, and the flow-rectifying channel 13 is configured as a one-way channel that only allows hydraulic oil to flow from the piston-side chamber R2 to the rod-side chamber R1.

[0032] As mentioned earlier, the valve housing 4 is fitted into the end of the cylinder 1 and seals the cylinder 1. Figure 1 The right end of the cylinder 1. Specifically, the valve housing 4 includes: a clamping part of the cylinder 1. Figure 1 The disc-shaped main body 4a between the right end and the bottom cover 11; from the main body 4a towards Figure 1 The left side protrudes and fits into cylinder 1. Figure 1 The fitting portion 4b on the inner periphery of the middle right end; from the main body portion 4a Figure 1 The recessed portion 4c with an opening at the right end; and the portion 4b with an opening at the right end. Figure 1 The recess 4d has an opening at the left end. The recess 4c is formed in the main body 4a via... Figure 1 The cutout 4e at the left end of the cylinder, which serves as a channel described later, communicates with the annular gap between the cylinder 1 and the outer cylinder 9. The recess 4d faces the piston-side chamber R2 and communicates with the piston-side chamber R2.

[0033] Furthermore, the valve housing 4 has six ports 6a that pass through the main body 4a and connect the recesses 4c and 4d to form the suction passage 6. Each port 6a is arranged at equal intervals on the same circumference centered on the axis of the valve housing 4, and connects the piston-side chamber R2 and the recess 4c. The number of ports 6a can be arbitrary and may be odd. However, when the cross-section of the port 6a is circular, providing multiple ports 6a makes it easier to ensure the flow area of ​​the suction passage 6. The cross-sectional shape of the port 6a is not limited to circular; it can also be other shapes such as arcuate or rectangular. Furthermore, the larger the flow area of ​​the suction passage 6, the smoother the flow of hydraulic oil from the reservoir T to the piston-side chamber R2, which is advantageous in preventing insufficient suction when the piston-side chamber R2 expands.

[0034] The bottom cover 11 is located on the opposite side of the piston-side chamber of the valve housing 4 and is welded onto the outer cylinder 9 to seal the outer cylinder 9. Figure 1 The right end of the middle, and the bottom cover 11 in Figure 1 The left end of the middle has a main body 4a Figure 1The right end of the recess 11a fits into the valve housing 4, and positions the valve housing 4 and the cylinder 1 fitted with the valve housing 4 radially. When the valve housing 4 is fitted with the bottom cover 11, a liquid chamber L is formed between the recess 4c of the valve housing 4 and the recess 11a of the bottom cover 11, that is, on the opposite side of the piston-side chamber of the valve housing 4. In addition, the depth of the recess 11a is shallower than the depth of the cut 4e of the valve housing 4, so that even if the valve housing 4 is fitted in the recess 11a, the communication between the liquid chamber L and the annular gap can be ensured.

[0035] Furthermore, the reservoir T is formed by the annular gap between the cylinder 1 and the outer cylinder 9. Additionally, the liquid chamber L, formed by the recess 4c and located opposite the piston-side chamber facing the valve housing 4, connects to the reservoir T via the cutout 4e and is also connected to the piston-side chamber R2 via the suction passage 6. Furthermore, the channel connecting the reservoir T and the liquid chamber L can be formed in a portion other than the cutout 4e, and can be located on the bottom cover 11 instead of the valve housing 4.

[0036] The reservoir T is filled with gas and hydraulic oil, similar to that in cylinder 1, and the liquid chamber L is also filled with hydraulic oil. Alternatively, the liquid used in the cylinder assembly C can be water, an aqueous solution, or any liquid other than hydraulic oil.

[0037] In addition, the bottom cover 11 has: from Figure 1 The fitting hole 11b opens at the left end, i.e., the end face facing the liquid storage tank T; and the cover channel 11c opens from the fitting hole 11b without branching along the way, and opens to the end opposite to the recess 4c of the valve housing 4 and facing the liquid chamber L, and in Figure 2 The right end of the cylinder assembly has a bracket 11d that can be connected to the body B of the railway vehicle. The cylinder assembly C is connected to the body B and the trolley W of the railway vehicle via brackets 2a and 11a, as shown below. Figure 3 As shown, it can be installed between the vehicle body B and the trolley W.

[0038] The opening end of the inner channel 11c facing the liquid chamber L formed by the recess 4c, i.e., the opening end of the discharge channel 5, opens at a different position than the opening end of the cut 4e, which serves as a channel connecting the liquid chamber L to the storage tank T, facing the liquid chamber L. Furthermore, as... Figure 1As shown, the opening end of the discharge channel 5 facing the liquid chamber L opens within the imaginary circle VC, which is the smallest diameter in the circle surrounding the entire port 6a, at a position axially opposite to the valve housing 4. That is, when the cylinder assembly C is viewed axially, the opening end of the discharge channel 5 opens within the imaginary circle VC on the side of the liquid chamber L of the bottom cover 11, at a position axially opposite to the valve housing 4. In this embodiment, since all ports 6a are arranged on the same circumference, the diameter of the imaginary circle VC is the length obtained by adding the diameter of the ports 6a to the diameter of the same circle. Furthermore, for example, even when the ports 6a are not equally spaced on the same circumference but are arranged in a range unevenly distributed circumferentially on the valve housing 4, the diameter of the imaginary circle VC is still the length obtained by adding the diameter of the same circle to the diameter of the ports 6a. However, in this case, it is sufficient to position the opening end of the discharge channel 5 as close as possible to the area where the ports 6a of the valve housing 4 are concentrated. Furthermore, the inner channel 11c opens at a position axially opposite to any one of the multiple ports 6a. Alternatively, the inner channel 11c may branch to have multiple openings, in which case the openings can be located at positions opposite to the range of the imaginary circle VC, i.e., positions directly opposite to ports 6a.

[0039] Furthermore, a check valve 7 is accommodated in the recess 4d of the valve housing 4. The check valve 7 has: an annular valve body 7a that can be seated on or off the bottom of the recess 4d to open and close ports 6a; an annular spring support 7b fixed to the inner circumference of the fitting portion 4b forming the sidewall 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 push 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 force. When the valve body 7a is in contact with the bottom of the recess 4d, it closes all ports 6a to cut off the suction passage 6. In addition, the outer circumference of the valve body 7a slides in contact with the sidewall of the recess 4d forming the valve housing 4, and is able to move without radial deviation when approaching the bottom away from the valve body 7a axially.

[0040] In check valve 7, when the pressure in liquid chamber L exceeds the pressure in piston-side chamber R2 and the pressure difference between the two reaches the opening pressure set by spring 7c, spring 7c is compressed due to the pressure exerted on valve body 7a, and suction passage 6 is opened. Furthermore, when the pressure in piston-side chamber R2 is higher than the pressure in liquid chamber L, check valve 7 remains seated in valve body 4, closing the outlet end of port 6a to cut off suction passage 6. Thus, check valve 7 only allows hydraulic oil to flow from reservoir T to piston-side chamber R2 and prevents flow to the opposite side, and sets suction passage 6 as a one-way passage that only allows hydraulic oil to flow from reservoir T to piston-side chamber R2.

[0041] Next, the rod guide 8 has: an annular cover 8a that fits into the inner circumference of the outer cylinder 9 and into which the rod 2 can be slidably inserted; from the cover 8a... Figure 1 The right end of the annular fitting portion 8b protrudes to fit into the outer periphery of the cylinder 1; and is provided on the cover portion 8a. Figure 1 The annular recess 8c on the outer periphery of the left end of the middle; located on the inner periphery of the cover 8a and from Figure 1 The groove 8d formed from the right end to the middle; located in the fitting part 8b Figure 1 The right end of the groove 8d faces the liquid storage tank T and is axially aligned with the fitting hole 11b of the bottom cover 11; and the channel 8f connects the groove 8d and the fitting hole 8e.

[0042] Furthermore, the rod guide 8, along with the cylinder 1 and valve housing 4, is housed within the outer cylinder 9. The bottom cover 11 is integrally welded to the outer cylinder 9 and screwed onto the outer cylinder 9. Figure 1 The locking nut 10 on the inner circumference of the left end of the cylinder is fixed together with the cylinder 1 and the valve housing 4 inside the outer cylinder 9.

[0043] In addition, an annular sealing member 12 is installed on the inner circumference of the rod guide 8, which slides in contact with the outer circumference of the rod 2 to seal between the rod 2 and the rod guide 8, so as to prevent liquid from leaking from the inside of the cylinder 1.

[0044] Furthermore, the conduit 14 housed in the storage tank T Figure 1 The left end of the guide tube 14 engages with the fitting hole 8e of the rod guide 8. Figure 4 The right end of the tube 14 is fitted into the fitting hole 11b of the bottom cover 11. Thus, the tube 14 is held in place by the rod guide 8 fixed to the outer cylinder 9 and the bottom cover 11, so that it will not fall off even if vibration is input to the cylinder device C.

[0045] The groove 8d in the rod guide 8 facing the rod-side chamber R1 communicates with the liquid chamber L via the channel 8f, the conduit 14, and the inner channel 11c in the bottom cover 11, and further communicates with the storage tank T via the cut 4e. Furthermore, a discharge channel 5 is formed through these grooves 8d, channels 8f, the conduit 14, and the inner channel 11c. Hydraulic oil flowing from the rod-side chamber R1 to the storage tank T via the discharge channel 5 passes through the liquid chamber L and reaches the storage tank T. Thus, the terminal side of the discharge channel 5 is formed by the conduit 14 held by the rod guide 8 and the bottom cover 11, and the unbranched inner channel 11c, and does not communicate with the storage tank T. Therefore, rectified liquid without entrained gas can be discharged into the liquid chamber L. Alternatively, instead of the conduit 14, a tubular member can be provided on the inner or outer circumference of the outer cylinder 9, forming an annular gap between the tubular member and the outer cylinder 9 as part of the discharge channel 5.

[0046] Furthermore, a damping valve 15 is provided in the channel 8f of the rod guide 8. In this embodiment, the damping valve 15 is a variable relief valve capable of adjusting the opening pressure and configured to open and close the discharge channel 5. It includes: a solenoid 15a; a valve body 15b driven by the solenoid 15a and provided in the channel 8f; a spring 15c that applies force to the valve body 15b in the closing direction; and a pilot channel 15d that causes the pressure of the rod-side chamber R1 to act on the valve body 15b in the opening direction. The solenoid 15a also applies a thrust to the valve body 15b in the direction opposing the force of the spring 15c. On the valve body 15b, the thrust of the solenoid 15a and the pressure of the rod-side chamber R1 act in the opening direction, and the force of the spring 15c acts in the closing direction. When the amount of current applied to the solenoid 15a is adjusted, the magnitude of the thrust of the solenoid 15a can be adjusted. Therefore, by adjusting the amount of current applied to the solenoid 15a, the opening pressure when the damping valve 15 opens the discharge channel 5 can be adjusted. Furthermore, besides a variable relief valve, the damping valve 15 can also be a valve capable of adjusting the resistance it applies to the flow of hydraulic oil. And if it is not necessary to adjust the damping force, it can also be a valve that does not have an actuator such as a solenoid and provides a set resistance to the flow of hydraulic oil. In this embodiment, the damping valve 15 is provided on the rod guide 8, but it could also be provided on the bottom cover 11.

[0047] In the cylinder assembly C configured in this way, when the cylinder assembly C extends relative to the cylinder 1 by means of an external input, the hydraulic oil in the rod-side chamber R1, which is reduced in size due to the movement of the piston 3, cannot pass through the rectifier channel 13 because the check valve 13a is closed. Therefore, the hydraulic oil moves to the reservoir T through the discharge channel 5 and the liquid chamber L. Since the check valve 7 is open, hydraulic oil is supplied from the reservoir T through the suction channel 6 and the liquid chamber L to the piston-side chamber R2, which expands due to the extension of the cylinder assembly C. Thus, when the cylinder assembly C performs the extension action, the pressure in the rod-side chamber R1 rises due to the pressure loss when the hydraulic oil flows through the damping valve 15 located in the discharge channel 5. On the other hand, since the pressure in the piston-side chamber R2 is almost the reservoir pressure, the cylinder assembly C generates a damping force on the extension side that hinders the extension action. Furthermore, since the pressure in the rod-side chamber R1 can be adjusted by regulating the opening pressure of the damping valve 15, the damping force on the extension side generated by the cylinder device C can be adjusted by regulating the amount of current applied to the solenoid 15a of the damping valve 15.

[0048] On the other hand, when the cylinder assembly C retracts, the hydraulic oil pushes open the check valve 13a and flows through the rectifier channel 13 from the piston-side chamber R2, which shrinks due to the movement of the piston 3, to the expanding rod-side chamber R1. Furthermore, within the entire cylinder 1, the hydraulic oil in the volume of the rod 2 entering the cylinder 1 becomes excess. This excess hydraulic oil moves from the cylinder 1 through the damping valve 15 in the discharge channel 5 and the liquid chamber L to the reservoir T. Thus, when the cylinder assembly C retracts, the hydraulic oil flows through the damping valve 15 in the discharge channel 5, causing the overall pressure within the cylinder 1 to rise. Consequently, the cylinder assembly C generates a damping force on the compression side that hinders the retraction action. Since the pressure capacity of the cylinder 1 can be adjusted by regulating the opening pressure of the damping valve 15, the damping force on the compression side generated by the cylinder assembly C can be adjusted by regulating the amount of current applied to the solenoid 15a of the damping valve 15.

[0049] As described above, when the cylinder assembly C extends or retracts, hydraulic oil circulates unidirectionally in the reservoir T, the piston-side chamber R2, and the rod-side chamber R1, and flows through the damping valve 15. Therefore, the cylinder assembly C can function as a unidirectional passive damper, generating damping force during both extension and retraction, and the damping force can be adjusted by regulating the opening pressure of the damping valve 15. Furthermore, as mentioned earlier, in the cylinder assembly C of this embodiment, since the pressure-bearing area of ​​the rod-side chamber R1 of the piston 3 is set to be half that of the pressure-bearing area of ​​the piston-side chamber R2, if the opening pressure of the damping valve 15 is the same, the damping force on the extension side and the damping force on the compression side of the cylinder assembly C can be made equal.

[0050] Furthermore, in the cylinder device C of this embodiment, the opening end of the discharge channel 5 communicates with the liquid chamber L located on the opposite side of the piston-side chamber of the valve housing 4, and the valve housing 4 is provided with a suction channel 6. When the cylinder device C extends, the hydraulic oil discharged from the cylinder 1 and passing through the damping valve 15 is discharged into the liquid chamber L. Additionally, since the opening end of the discharge channel 5 facing the liquid chamber L is at a different position than the opening end of the cut 4e on the liquid chamber L side, and the opening 4e is a channel connecting the liquid chamber L and the reservoir T, the hydraulic oil flowing through the discharge channel 5 passes through the liquid chamber L and is discharged into the reservoir T through the cut 4e. Thus, since the hydraulic oil that has already passed through the discharge channel 5 has temporarily passed through the liquid chamber L, the pressure in the liquid chamber L tends to become higher than that in the reservoir T due to the inflow of hydraulic oil. Simultaneously, the hydraulic oil that has just passed through the discharge channel 5 and has not yet come into contact with the gas can be forcibly injected into the piston-side chamber R2 through the suction channel 6. Therefore, even if the cylinder assembly C extends at high speed, it can suppress the insufficient intake of hydraulic oil in the piston-side chamber R2 and the intrusion of hydraulic oil carrying gas into the cylinder 1, thus enabling the set damping force to be exerted.

[0051] Thus, the cylinder device C in this embodiment includes: a cylinder 1; a rod 2 movably inserted into the cylinder 1 along the axial direction; a piston 3 slidably inserted into the cylinder 1 and connected to one end of the rod 2, dividing the cylinder 1 into a rod-side chamber R1 filled with hydraulic oil (liquid) and a piston-side chamber R2; a reservoir T storing gas and hydraulic oil (liquid); a valve housing 4 sealing the end of the cylinder 1; a bottom cover 11 disposed on the opposite side of the piston-side chamber of the valve housing 4; and a valve body formed between the valve housing 4 and the bottom cover 11. The valve body 4 includes a liquid chamber L connected to the storage tank T; a discharge channel 5 that connects the rod-side chamber R1 and the liquid chamber L but not the storage tank T; a suction channel 6 provided in the valve body 4; a damping valve 15 provided in the discharge channel 5; and a check valve 7 provided in the valve body 4 that sets the suction channel 6 as a one-way channel that only allows liquid to flow from the storage tank T to the piston-side chamber R2; wherein the discharge channel 5 has an inner cover channel 11c provided in the bottom cover 11, the inner cover channel 11c having an open end facing the liquid chamber L and not branching.

[0052] In the cylinder device C constructed in this way, as mentioned above, since the hydraulic oil (liquid) discharged from the cylinder 1 and passing through the damping valve 15 without entrained gas can be rectified through the unbranched cover passage 11c and directly discharged into the liquid chamber L located on the opposite side of the piston side chamber of the valve housing 4 without passing through the reservoir T, the hydraulic oil (liquid) without entrained gas can be forcibly injected into the piston side chamber R2 through the suction passage 6 while increasing the pressure of the liquid chamber L.

[0053] In summary, according to the cylinder device C of this embodiment, even at high speeds of extension and retraction, it is possible to suppress the insufficient intake of hydraulic oil in the piston-side chamber R2 and the intrusion of hydraulic oil (liquid) containing gas into the cylinder 1, thus enabling the application of the set damping force.

[0054] Furthermore, the opening end of the inner cover channel 11c, which serves as the opening end of the discharge channel 5, towards the liquid chamber L can also be located at a position other than the position opposite to the valve housing 4 within the range of the imaginary circle VC of the bottom cover 11. Moreover, depending on the shape and structure of the valve housing 4 and the bottom cover 11, even if the discharge channel 5 is connected to the liquid chamber L radially due to the arrangement of the discharge channel 5, the pressure in the liquid chamber L increases due to the inflow of hydraulic oil flowing through the discharge channel 5. This allows the hydraulic oil that has just flowed through the discharge channel 5 without contacting the gas to be forcibly injected into the piston-side chamber R2 through the suction channel 6. Therefore, the effects of the present invention are not lost. In contrast, in the cylinder device C of this embodiment, the opening end of the discharge channel 5, which is the opening end of the inner cover channel 11c facing the liquid chamber L, is set within the range of the imaginary circle VC with the smallest diameter surrounding the entire port 6a, at a position axially opposite to the valve housing 4. In the cylinder device C constructed in this way, since the opening end of the discharge passage 5 facing the liquid chamber L is positioned relative to the imaginary circle VC with the smallest diameter in 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 and is easily fed into the piston-side chamber R2 through the suction passage 6, effectively suppressing the occurrence of insufficient hydraulic oil intake in the piston-side chamber R2. Furthermore, even when the ports 6a are not equally spaced on the same circumference and are arranged in an uneven range in the circumferential direction of the valve body 4, as long as the opening end of the discharge passage 5 is located within the imaginary circle VC and in a position opposite to the axial direction of the valve body 4, the opening end of the discharge passage 5 can be arranged relative to the portion of the valve body 4 where the ports 6a are concentrated as much as possible.

[0055] Furthermore, in the cylinder device C of this embodiment, the opening end of the discharge channel 5 is the opening end of the inner cover channel 11c facing the liquid chamber L, which is directly opposite the opening of the inlet side of the suction channel 6 of the valve housing 4. Specifically, in this embodiment, the opening end of the inner cover channel 11c provided in the bottom cover 11 is directly opposite the inlet end of any one of the plurality of ports 6a provided in the suction channel 6 of the valve housing 4, i.e., the opposite end of the piston-side chamber. According to the cylinder device C configured in this way, since the hydraulic oil discharged to the liquid chamber L through the discharge channel 5 flows to the port 6a, it is easier to deliver the hydraulic oil to the piston-side chamber R2 through the suction channel 6, and the occurrence of insufficient hydraulic oil intake in the piston-side chamber R2 can be effectively suppressed.

[0056] Furthermore, since the cylinder device C of this embodiment has a rectifier channel 13 that only allows hydraulic oil (liquid) to flow from the piston-side chamber R2 to the rod-side chamber R1, the cylinder device C is configured as a one-way shock absorber. In a one-way shock absorber, when the cylinder device C extends, the entire amount of hydraulic oil required to expand the volume of the piston-side chamber R2 in conjunction with the movement of the piston 3 needs to be supplied to the piston-side chamber R2. However, as mentioned above, the cylinder device C of this embodiment can increase the pressure in the liquid chamber L during the extension operation and can smoothly supply hydraulic oil without entrained gas to the piston-side chamber R2, thus achieving the set damping force even when configured as a one-way type. Therefore, the cylinder device C of this embodiment improves the practicality of a shock absorber configured as a one-way type.

[0057] Furthermore, as mentioned earlier, the cylinder assembly C is a unidirectional shock absorber. However, it can also be a bidirectional shock absorber as long as hydraulic oil can be discharged from the rod-side chamber R1 to the liquid chamber L through the discharge channel 5 during extension, and hydraulic oil insufficient in the piston-side chamber R2 can be supplied from the reservoir T. When the cylinder assembly is configured as a bidirectional shock absorber, for example, it can be configured as follows: Figure 4 The cylinder device C1 of the first modified embodiment shown can be configured as described. Figure 5 The structure of the cylinder device C1 is shown in principle, but components marked with the same reference numerals refer to the same components as those in the cylinder device C of one embodiment. The cylinder device C1 eliminates the flow channel 13 of the piston 3 in the cylinder device C of one embodiment, and instead includes: a channel 16, which is arranged alongside the discharge channel 5 and bypasses the damping valve 15; a check valve 17, which is provided in the channel 16 and allows hydraulic oil to flow only from the reservoir T toward the rod-side chamber R1; a channel 18, which is arranged alongside the intake channel 6 and bypasses the check valve 7; and a compression-side damping valve 19, which is provided in the channel 18 and allows hydraulic oil to flow only from the piston-side chamber R2 toward the reservoir T, and applies resistance to the flow of the hydraulic oil.

[0058] Channel 16 connects the reservoir T and the rod-side chamber R1 independently of the discharge channel 5, but it may also share a portion with the discharge channel 5, and may also connect the rod-side chamber R1 with the liquid chamber L. Similarly, channel 18 connects the piston-side chamber R2 with the liquid chamber L independently of the suction channel 6, but it may also share a portion with the suction channel 6, and may also connect the piston-side chamber R2 with the reservoir T.

[0059] In the cylinder assembly C1 configured in this manner, during the extension action, the hydraulic oil in the rod-side chamber R1, which shrinks due to the movement of the piston 3, flows through the damping valve 15 and the liquid chamber L to the reservoir T. Hydraulic oil is then supplied from the reservoir T to the piston-side chamber R2, which expands due to the movement of the piston 3, via the liquid chamber L and the suction passage 6. During the extension action of the cylinder assembly C1, the hydraulic oil discharged from the discharge passage 5 is discharged to the liquid chamber L, located on the opposite side of the piston-side chamber in the valve housing 4. Therefore, hydraulic oil without gas entrainment is forcibly injected into the piston-side chamber R2. Furthermore, during the retraction action of the cylinder assembly C1, the hydraulic oil in the piston-side chamber R2, which shrinks due to the movement of the piston 3, flows through the compression-side damping valve 19 to the reservoir T. Hydraulic oil is then supplied from the reservoir T to the rod-side chamber R1, which expands due to the movement of the piston 3, via the passage 16. Furthermore, the amount of hydraulic oil required in the rod-side chamber R1 when the cylinder device C1 retracts is the amount of oil obtained by multiplying the value obtained by subtracting the cross-sectional area of ​​the rod 2 from the cross-sectional area of ​​the piston 3 by the amount of movement of the piston 3. In the cylinder device C1 of this embodiment, since the cross-sectional area of ​​the rod 2 is half the cross-sectional area of ​​the piston 3, the amount of hydraulic oil required in the rod-side chamber R1 when the cylinder device C1 retracts is half the amount of hydraulic oil required in the piston-side chamber R2 when the cylinder device C1 extends. Therefore, when the cylinder device C1 retracts, it is not a problem even if the outlet end of the channel 18 equipped with the compression-side damping valve 19 is not located near the inlet of the check valve 17. Alternatively, the outlet end of the channel 18 can be located as close as possible to or opposite to the inlet of the port of the check valve 17 provided on the component equipped with the check valve 17, thereby allowing hydraulic oil to be injected into the rod-side chamber R1. Thus, even if the cylinder device C1 is configured as a two-way type, since working oil is discharged into the liquid chamber L located on the opposite side of the piston side chamber of the valve housing 4 during the extension action, the pressure of the liquid chamber L can be increased and hydraulic oil without gas entrainment can be forcibly supplied to the piston side chamber R2. Therefore, even if the cylinder device C1 extends and retracts at high speed, the set damping force can be exerted.

[0060] Furthermore, when the channel 18 is connected to the liquid chamber L, when the cylinder device C1 performs a retraction action, hydraulic oil flows from the piston-side chamber R2 into the liquid chamber L, and the pressure in the liquid chamber L tends to increase. Therefore, when the cylinder device C1 switches to an extension action, hydraulic oil is rapidly supplied to the piston-side chamber R2. Thus, when the cylinder device C1 switches from a retraction action to an extension action, the damping force also rises rapidly.

[0061] Furthermore, when the cylinder assembly C2 is configured as a semi-active damper, as long as... Figure 5 The cylinder device C2 of the second variation of the first embodiment shown can be configured as described. Figure 2The structure of the cylinder device C2 is shown in principle, but the parts marked with the same reference numerals refer to the same parts as the cylinder device C in one embodiment.

[0062] Based on the structure of cylinder device C in one embodiment, cylinder device C2 further includes: a first channel 20 that connects rod-side chamber R1 and piston-side chamber R2; a first switching valve 21 disposed in the middle of the first channel 20; a second channel 22 that connects piston-side chamber R2 and liquid storage tank T; and a second switching valve 23 disposed in the middle of the second channel 22.

[0063] The first channel 20 is formed by a channel disposed inside the rod guide 8, the bottom cover 11 and the valve housing 4 and a conduit 24 mounted on the rod guide 8 and the bottom cover 11, and connects the rod side chamber R1 and the piston side chamber R2.

[0064] The first switching valve 21, located in the first channel 20, is an electromagnetic switching valve that opens the first channel 20 to the connected position when energized and closes the first channel 20 to the cut-off position when not energized, and is located on the rod guide 8. Alternatively, the first switching valve 21 can also be located on the bottom cover 11.

[0065] The second channel 22 shares a portion of the channel with the discharge channel 5 and the first channel 20, and connects the piston-side chamber R2 to the storage tank T through conduits 14 and 24. Alternatively, the second channel 22 can be set independently of the discharge channel 5 and the first channel 20, but by sharing a portion of the channel with the discharge channel 5 and the first channel 20, the number of components and processing time can be reduced.

[0066] The second switching valve 23, located in the second channel 22, is an electromagnetic switching valve that opens the second channel 22 to the connected position when energized and closes the second channel 22 to the cut-off position when not energized, and is located on the rod guide 8. Alternatively, the second switching valve 23 can also be located on the bottom cover 11.

[0067] In the cylinder assembly C2 configured in this manner, when the first switching valve 21 is in the connected position and the second switching valve 23 is in the disconnected position, the rod-side chamber R1 and the piston-side chamber R2 are connected via the first channel 20, while the connection between the piston-side chamber R2 and the reservoir T via the second channel 22 is disconnected. In this state, when the cylinder assembly C2 is subjected to an extension action of the rod 2 retracting from the cylinder 1 by external input, hydraulic oil moves from the reduced rod-side chamber R1 through the first channel 20 to the expanded piston-side chamber R2. Furthermore, within the entire cylinder 1, the hydraulic oil in the volume portion where the rod 2 retracts from the cylinder 1 is insufficient, and the insufficient hydraulic oil moves from the reservoir T to the piston-side chamber R2 via the check valve 7 through the liquid chamber L and the suction channel 6. Thus, when the first switch valve 21 is in the connected position and the second switch valve 23 is in the cut-off position, even if the cylinder device C2 extends, the hydraulic oil will not flow through the damping valve 15 located in the discharge channel 5. Since the rod-side chamber R1 and the piston-side chamber R2 are almost at the reservoir pressure, the cylinder device C2 will not generate a damping force on the extension side that would hinder the extension action.

[0068] On the other hand, with the first switch valve 21 in the open position and the second switch valve 23 in the closed position, when the cylinder assembly C2 retracts, hydraulic oil moves from the shrinking piston-side chamber R2 to the expanding rod-side chamber R1 via the first channel 20. Furthermore, within the entire cylinder 1, the hydraulic oil in the volume of the rod 2 entering the cylinder 1 becomes excess. Since the second channel 22 is closed, the excess hydraulic oil in the cylinder 1 moves from the cylinder 1 through the damping valve 15 of the discharge channel 5 and the liquid chamber L to the reservoir T. Thus, with the first switch valve 21 in the open position and the second switch valve 23 in the closed position, when the cylinder assembly C2 retracts, hydraulic oil flows through the damping valve 15 located in the discharge channel 5, causing the overall pressure within the cylinder 1 to rise. Therefore, the cylinder assembly C2 generates a damping force on the compression side that hinders the retraction action. Since the pressure inside the cylinder 1 can be adjusted by regulating the opening pressure of the damping valve 15, the damping force on the compression side of the cylinder assembly C2 can be adjusted by regulating the amount of current applied to the damping valve 15.

[0069] Furthermore, in the cylinder assembly C2, when the first switching valve 21 is in the off position and the second switching valve 23 is in the connected position, the communication between the rod-side chamber R1 and the piston-side chamber R2 via the first channel 20 is cut off, while the piston-side chamber R2 and the reservoir T are connected via the second channel 22. In this state, when the cylinder assembly C2 extends relative to the cylinder 1 due to external input, hydraulic oil flows from the reduced rod-side chamber R1 through the damping valve 15 of the discharge channel 5 and the liquid chamber L to the reservoir T because the first channel 20 is cut off. Hydraulic oil then flows from the reservoir T through the second channel 22 and is supplied to the expanded piston-side chamber R2 due to the extension action of the cylinder assembly C2. Thus, with the first switching valve 21 in the off position and the second switching valve 23 in the open position, when the cylinder assembly C2 extends, hydraulic oil flows through the damping valve 15 located in the discharge channel 5, causing the pressure in the rod-side chamber R1 to rise. On the other hand, since the pressure in the piston-side chamber R2 is almost the same as the reservoir pressure, the cylinder assembly C2 generates a damping force on the extension side that hinders the extension action. Since the pressure in the rod-side chamber R1 can be adjusted by regulating the opening pressure of the damping valve 15, the damping force on the extension side generated by the cylinder assembly C2 can be adjusted by regulating the amount of current applied to the damping valve 15.

[0070] On the other hand, when the first switch valve 21 is in the off position and the second switch valve 23 is in the open position, when the cylinder assembly C2 retracts, the hydraulic oil pushes open the check valve 13a and flows from the reduced piston-side chamber R2 through the rectifier channel 13 to the expanded rod-side chamber R1. Furthermore, within the entire cylinder 1, the hydraulic oil in the volume of the rod 2 entering the cylinder 1 becomes excess, and this excess hydraulic oil moves from the cylinder 1 through the second channel 22 to the reservoir T. Thus, when the first switch valve 21 is in the off position and the second switch valve 23 is in the open position, even if the cylinder assembly C2 retracts, the hydraulic oil will not flow through the damping valve 15 located in the discharge channel 5. The rod-side chamber R1 and the piston-side chamber R2 are almost at the reservoir pressure, therefore the cylinder assembly C2 will not generate a damping force on the compression side that would hinder the retraction action.

[0071] As described above, in the cylinder device C2 of this embodiment, the pressure-bearing area of ​​the rod-side chamber R1 of the piston 3 is set to be half the pressure-bearing area of ​​the piston-side chamber R2. Therefore, if the opening pressure of the damping valve 15 is the same, the damping force on the extension side and the damping force on the compression side of the cylinder device C2 are equal. Therefore, if the pressure-bearing area of ​​the rod-side chamber R1 of the piston 3 is set to be half the pressure-bearing area of ​​the piston-side chamber R2, the damping force of the cylinder device C2 can be easily controlled.

[0072] As described above, when the first switching valve 21 is in the connected position and the second switching valve 23 is in the disconnected position, the cylinder device C2 generates damping force only during the contraction action and not during the extension action. Furthermore, when the first switching valve 21 is in the disconnected position and the second switching valve 23 is in the connected position, the cylinder device C2 generates damping force only during the extension action and not during the contraction action.

[0073] exist Figure 6 As shown in the diagram where cylinder assembly C2 is installed on a railway vehicle, when the vehicle body B moves to the right relative to the trolley W, cylinder assembly C2 retracts, and when the vehicle body B moves to the left relative to the trolley W, cylinder assembly C2 extends. In this case, cylinder assembly C2 uses the damping force on the compression side to suppress the rightward movement of the vehicle body B. However, when the vehicle body B and trolley W move to the right, and the trolley W moves relatively slowly, it retracts to generate the damping force on the compression side, thus suppressing the vibration of the vehicle body B. But when the vehicle body B and trolley W move to the right, and the trolley W moves relatively fast, cylinder assembly C2 does not retract but extends. Here, when cylinder assembly C2 generates the damping force on the extension side, since the extension of cylinder assembly C2 is suppressed, the rightward movement of the trolley W is transmitted to the vehicle body B. However, in the cylinder device C2 of this embodiment, since it can function as a semi-active damper with a unilateral effect, it can be controlled so that when the vehicle body B and the trolley W move to the right and the trolley W moves at a relatively high speed, only the compression-side damping force is generated, thereby preventing the vibration of the vehicle body B from being amplified. Furthermore, when the vehicle body B and the trolley W move to the left and the trolley W moves at a relatively high speed, it can be controlled to generate only the extension-side damping force of the cylinder device C2. Thus, when the direction in which the damping force generated by the cylinder device C2 is due to the vibration of the trolley W of the railway vehicle amplifies the vibration of the vehicle body B, the cylinder device C2 can function as a damper with a unilateral effect, preventing it from generating force in that direction. Therefore, this cylinder device C2 can be easily semi-actively controlled according to Carnop's theory, and thus can function as a semi-active damper.

[0074] Next, if both the first switching valve 21 and the second switching valve 23 are set to the off position, the circuit structure of the cylinder device C2 is outwardly identical to that of the cylinder device C in an embodiment that does not have the first channel 20, the first switching valve 21, the second channel 22, and the second switching valve 23. Therefore, in this case, the hydraulic oil of the cylinder device C2 will definitely pass through the damping valve 15 during the extension and retraction action, thus functioning as a unidirectional shock absorber that exerts damping force during both the extension and retraction actions.

[0075] Furthermore, in the cylinder assembly C2, when both the first switching valve 21 and the second switching valve 23 are in the connected position, the rod-side chamber R1 and the piston-side chamber R2 are connected via the first channel 20, and the piston-side chamber R2 and the reservoir T are connected via the second channel 22. That is, when the cylinder assembly C2 is in this state, the rod-side chamber R1 and the piston-side chamber R2 are always connected to the reservoir T via the first channel 20 and the second channel 22. Therefore, regardless of whether the cylinder assembly C2 performs an extension or retraction action, the cylinder 1 is under reservoir pressure, and the cylinder assembly C2 is in an unloading state where no damping force is exerted.

[0076] Even in the cylinder device C2 configured in this way, when the hydraulic oil exerts a damping force during the extension action, it is discharged from the rod-side chamber R1 through the discharge passage 5 to the liquid chamber L formed between the valve housing 4 and the bottom cover 11. Thus, similar to the cylinder device C in one embodiment, the cylinder device C2 can increase the pressure in the liquid chamber L and forcefully supply hydraulic oil without gas entrainment to the piston-side chamber R2, so that the set damping force can be exerted even at high-speed extension and retraction.

[0077] Alternatively, it can be like Figure 6 Like the cylinder device C3 in the third variation of the first embodiment shown, a pump P and a motor M are added to the structure of the cylinder device C2 so that the cylinder device C3 functions as an actuator.

[0078] Specifically, the cylinder device C3 of the third modification, based on the structure of the cylinder device C2, further includes: a supply channel 25 that connects the rod-side chamber R1 to the reservoir T without passing through the discharge channel 5 and the liquid chamber L; a pump P, which is disposed inside the bottom cover 11 and can supply hydraulic oil from the reservoir T to the rod-side chamber R1 through the supply channel 25; a motor M, which is mounted on the bottom cover 11 and drives the pump P; and a check valve 26, which is disposed in the middle of the supply channel 25 and between the pump P and the rod-side chamber R1, allowing hydraulic oil to flow only from the pump P to the rod-side chamber R1.

[0079] The supply channel 25 is formed by a channel provided inside the rod guide 8 and the bottom cover 11 and a conduit 27 erected in the rod guide 8 and the bottom cover 11, and connects the rod side chamber R1 to the liquid storage tank T.

[0080] Pump P is housed within the bottom cover 11. In this embodiment, it is a gear pump positioned midway through the supply channel 25. Furthermore, motor M is mounted on the bottom cover 11 and powers the drive shaft of pump P. When pump P is driven by motor M, it draws hydraulic oil from the reservoir T and supplies it to the rod-side chamber R1. Alternatively, pump P can be any pump other than a gear pump. Furthermore, motor M can also include a speed reducer; in this case, the output shaft of the speed reducer can be connected to pump P. Additionally, pump P and motor M can also be housed within the rod guide 8.

[0081] In the cylinder assembly C3 configured in this manner, when the pump P is driven by the motor M, and the first switching valve 21 is in the connected position and the second switching valve 23 is in the cut-off position, the rod-side chamber R1 and the piston-side chamber R2 are connected through the first channel 20, and hydraulic oil is supplied to both from the pump P. The supply of hydraulic oil increases the total volume of the rod-side chamber R1 and the piston-side chamber R2, and the rod 2 moves from the cylinder 1 to... Figure 6 The cylinder C3 extends to the left, causing it to extend. When the pressure in the rod-side chamber R1 and the piston-side chamber R2 exceeds the opening pressure of the damping valve 15, the damping valve 15 opens, and hydraulic oil is discharged to the reservoir T via the discharge channel 5 and the liquid chamber L. Therefore, the pressure in the rod-side chamber R1 and the piston-side chamber R2 is controlled to be equal to the opening pressure of the damping valve 15. Thus, the cylinder C3 exerts a thrust in the extension direction, which is equal to the value obtained by multiplying the difference in pressure-bearing areas between the piston-side chamber R2 and the rod-side chamber R1 in the piston 3 by the opening pressure of the damping valve 15. Furthermore, the thrust generated by the cylinder C3 is adjusted by regulating the amount of current applied to the damping valve 15.

[0082] On the other hand, in the cylinder assembly C3, when the pump P is driven by the motor M, and the first switching valve 21 is in the off position and the second switching valve 23 is in the open position, hydraulic oil is only supplied to the rod-side chamber R1, causing the rod-side chamber R1 to expand. Conversely, hydraulic oil is discharged from the contracted piston-side chamber R2 through the open second channel 22 to the reservoir T. Thus, the piston 3 is pushed... ​ Pushing to the right in the piston 3 causes the cylinder assembly C3 to retract. In this situation, the pressure in the piston-side chamber R2 is equal to the reservoir pressure, while the pressure in the rod-side chamber R1 is controlled to be equal to the opening pressure of the damping valve 15. Therefore, the cylinder assembly C3 exerts a thrust in the retraction direction, which is equal to the value obtained by multiplying the pressure-bearing area of ​​the rod-side chamber R1 in the piston 3 by the opening pressure of the damping valve 15. Furthermore, the thrust generated by the cylinder assembly C3 is adjusted by regulating the amount of current applied to the damping valve 15.

[0083] Thus, if, while driving pump P, one of the first switching valve 21 and the second switching valve 23 is set to the connected position and the other of the first switching valve 21 and the second switching valve 23 is set to the cut-off position according to the direction of the thrust to be output by cylinder device C3, then cylinder device C3 functions as an actuator. Furthermore, in this embodiment, since damping valve 15 is a variable relief valve, it is also utilized for controlling the thrust when cylinder device C3 functions as an actuator.

[0084] Furthermore, when pump P stops, similar to cylinder assembly C2, cylinder assembly C3 includes a rectifier channel 13, a suction channel 6, a first channel 20, a second channel 22, a discharge channel 5, a first switching valve 21 provided in the first channel 20, a second switching valve 23 provided in the second channel 22, and a damping valve 15 provided in the discharge channel 5. Therefore, by switching the first switching valve 21 and the second switching valve 23, it can function as a semi-active or passive shock absorber, and can also be in an unloaded state. In addition, when cylinder assembly C3 is in the unloaded state, it will not extend or retract even when driving pump P, and will not generate damping force for vibrations caused by external forces.

[0085] Even in the cylinder device C3 configured in this way, when functioning as a shock absorber, hydraulic oil is discharged from the rod-side chamber R1 via the discharge passage 5 to the liquid chamber L, which is located on the opposite side of the piston-side chamber of the valve housing 4, in a manner that exerts damping force during extension. In the cylinder device C3, since the pump P draws hydraulic oil directly from the reservoir 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 due to the driving of the pump P. Thus, even in the cylinder device C3, which is equipped with the pump P to generate thrust, similar to the cylinder device C of one embodiment, the pressure in the liquid chamber L can be increased and hydraulic oil without gas entrainment can be forcibly supplied to the piston-side chamber R2, so that the set damping force can be exerted even during high-speed extension and retraction.

[0086] Furthermore, the shape and structure of the rod guide 8, valve housing 4, and bottom cover 11 in the cylinder assemblies C, C1, C2, and C3 can be arbitrarily changed, and they can also be formed from multiple components. In addition, the cylinder assemblies C, C1, C2, and C3 can be used not only to suppress the vibration of railway vehicles, but also to suppress the vibration of buildings, machinery, and vehicles, among other applications.

[0087] The preferred embodiments of the present invention have been described in detail above, but modifications, variations and alterations can be made without departing from the scope of the claims.

[0088] Symbol Explanation

[0089] 1 cylinder

[0090] 2 rods

[0091] 3 Pistons

[0092] 4 valve housing

[0093] 4e Incision (Channel)

[0094] 5. Discharge Channel

[0095] 6. Inhalation Channel

[0096] 6a port

[0097] 7. Check valve

[0098] 8. Rod guide

[0099] 11. Bottom Cover

[0100] 11c Inner channel of the cover

[0101] 13 Rectifier Channels

[0102] 15 Damping valve

[0103] 20 First Channel

[0104] 21 First switching valve

[0105] 22 Second Channel

[0106] 23 Second switching valve

[0107] 25 Supply Channels

[0108] C,C1,C2,C3 cylinder assembly

[0109] L liquid chamber

[0110] P pump

[0111] R1 rod side chamber

[0112] R2 Piston Side Chamber

[0113] T-type storage tank

[0114] VC Imaginary Circle

Claims

1. A cylinder device characterized by comprising: Possessing: a cylinder; a rod member which is axially movably inserted into the cylinder; a piston which is slidably inserted into the cylinder and is connected to one end of the rod member, and which divides the cylinder into a rod member side chamber filled with a liquid and a piston side chamber; a liquid reservoir which stores a gas and a liquid; a valve housing which closes an end of the cylinder; a bottom cover which is arranged on the opposite side of the piston side chamber of the valve housing; a liquid chamber which is formed between the valve housing and the bottom cover and which communicates with the liquid reservoir; a discharge passage which communicates the rod member side chamber and the liquid chamber without communicating with the liquid reservoir; a suction passage which is provided to the valve housing; a damping valve which is provided to the discharge passage; and a check valve which is provided to the valve housing and which sets the suction passage to allow the flow of the liquid from the liquid reservoir to the piston side chamber only; wherein the discharge passage has a lid inner passage which is provided to the bottom cover, which has an open end facing the liquid chamber, and which is not connected to other passages than the discharge passage and is not branched.

2. The cylinder device according to claim 1, characterized in that: the suction passage has a plurality of ports which are formed in parallel on the valve housing in the circumferential direction, and the open end of the discharge passage is opened at a position opposite to the axial direction of the valve housing within a range of an imaginary circle having the smallest diameter among circles around the entire ports.

3. The cylinder device according to claim 2, characterized in that: the open end of the discharge passage is directly opposite to the opening of the inlet side of the suction passage of the valve housing.

4. The cylinder device according to any one of claims 1 to 3, characterized in that Possessing: a first passage which communicates the rod member side chamber and the piston side chamber; a first on-off valve which is provided to the first passage; a second passage which communicates the piston side chamber and the liquid reservoir; a second on-off valve which is provided to the second passage; a supply passage which communicates the liquid reservoir and the rod member side chamber without passing through the discharge passage and the liquid chamber; and a pump which is provided to the supply passage and which can supply the liquid from the liquid reservoir to the rod member side chamber.

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