Cylinder device

Abstract

An object of the present invention is to provide a cylinder device that can reduce the number of components and miniaturize the device, while also eliminating the need to worry about liquid leakage to the outside. The cylinder device includes a cylinder, a piston that can be slidably inserted into the cylinder, a rod guide and a bottom cover that close the ends of the cylinder, a rod inserted into the cylinder and connected to the piston, a rod-side chamber and a piston-side chamber formed in the cylinder by the piston, a liquid storage tank, a rectifying passage, a suction passage, a first passage, a first switching valve, a second passage, a second switching valve, a discharge passage, and a control valve; when either the rod guide or the bottom cover is used as a cover member, a first valve body, a second valve body, and a control valve body are built into the cover member, and a first solenoid, a second solenoid, and a third solenoid are installed outside the cover member.

Description

Technical Field

[0001] The present invention relates to a cylinder device. Background Art

[0002] Conventionally, as such a cylinder device, there are known, for example, a shock absorber and an actuator that are used to be installed between the body and the bogie of a railway vehicle and suppress vibrations of the body in the left-right direction with respect to the vehicle traveling direction.

[0003] In recent years, particularly in articulated vehicles with intense vibrations, vehicles with current collection devices, and special vehicles that require special fees, in order to improve the riding comfort of railway vehicles, the shock absorber is set as a semi-active shock absorber, or the actuator also has a semi-active shock absorber function.

[0004] In such semi-active shock absorbers and actuators, in addition to a pressure control valve provided for controlling the pressure in the cylinder, there are also two switching valves provided on the passages between the rod side chamber and the piston side chamber in the cylinder and on the passage between the piston side chamber and the reservoir. Moreover, for example, as disclosed in JP2016-084841A, the pressure control valve and the two switching valves are solenoid valves and are mounted on a valve block for connecting to a bottom cover that closes the end of the cylinder. Summary of the Invention

[0005] Problems to be Solved by the Invention

[0006] In this way, when the pressure control valve and the switching valves are connected to the bottom cover by using the valve block, since the valve block and the bottom cover are fastened by bolts, it should be noted that there is a possibility of leakage of hydraulic oil from between the valve block and the bottom cover due to loosening of the bolts caused by vibration input.

[0007] Since the valve block and the bottom cover are fastened by bolts, a space for installing the bolts is required, resulting in a problem of enlargement of the cylinder device and an increase in the number of components.

[0008] Therefore, an object of the present invention is to provide a cylinder device that can reduce the number of components and miniaturize the device, while also eliminating the concern about leakage of liquid to the outside.

[0009] Solutions for Solving the Problems

[0010] In order to achieve the above object, the cylinder device in the technical solution of the present invention includes: a cylinder; a cover member provided at one end of the cylinder to close the end of the cylinder; a piston slidably inserted into the cylinder; a rod inserted into the cylinder and connected to the piston; a rod-side chamber and a piston-side chamber formed in the cylinder by the piston; a liquid storage tank for storing liquid; a rectifying passage that only allows the liquid to flow from the piston-side chamber to the rod-side chamber; an inhalation passage that only allows the liquid to flow from the liquid storage tank to the piston-side chamber; a first passage that communicates the rod-side chamber and the piston-side chamber; a first switching valve provided in the middle of the first passage; a second passage that communicates the piston-side chamber and the liquid storage tank; a second switching valve provided in the middle of the second passage; a discharge passage that connects the rod-side chamber to the liquid storage tank; and a control valve provided in the middle of the discharge passage; wherein the first switching valve has a first valve body provided in the cover member to switch the first passage and a first solenoid installed on the cover member to drive the first valve body; the second switching valve has a second valve body provided in the cover member to switch the second passage and a second solenoid installed on the cover member to drive the second valve body; the control valve has a control valve body provided in the cover member to switch the discharge passage and a third solenoid provided in the cover member to apply a thrust to the control valve body.

[0011] In the cylinder device configured in this way, since the first valve body of the first switching valve, the second valve body of the second switching valve, and the control valve body of the control valve are built into the cover member as a single component, it is not necessary to fix the valve blocks constituting the first switching valve, the valve blocks constituting the second switching valve, and the valve blocks constituting the control valve to the cover member using bolts respectively.

[0012] In addition, the cover member in the cylinder device can be either a rod guide that closes one end of the cylinder and allows the rod to be inserted into the inner peripheral side to guide the axial movement of the rod, or a bottom cover connected to the other end of the cylinder. When the cover member is used as the rod guide, since the first switching valve, the second switching valve, and the control valve, which are heavy objects, are concentrated on the rod guide, the center of gravity of the cylinder device is located near the rod guide, thereby improving the weight balance of the cylinder device and preventing a biased load from being applied to only one of the vibration-proof rubbers of the brackets on both ends where the cylinder device is installed. In addition, when the cover member is used as the bottom cover, since the first switching valve, the second switching valve, and the control valve, which are heavy objects, are concentrated on the bottom cover, it is not necessary to apply a large load to the sliding contact portion between the rod and the rod guide, so that the friction force between the rod and the bushing provided on the inner periphery of the rod guide can be reduced, which is beneficial to the smooth expansion and contraction of the cylinder device.

[0013] In addition, the cylinder device includes: a supply passage that communicates the liquid storage tank and the rod-side chamber; a pump that is disposed in the middle of the supply passage and sucks liquid from the liquid storage tank and supplies the liquid to the rod-side chamber; and a motor that drives the pump. The cover member can be either a rod guide that closes one end of the cylinder and allows the rod to be inserted through the inner periphery to guide the axial movement of the rod, or a bottom cover that closes the other end of the cylinder, or the pump and the motor can be mounted on the other of the rod guide and the bottom cover. According to the cylinder device configured in this way, since the first switching valve, the second switching valve, and the control valve, which are heavy objects, and the pump and the motor, which are also heavy objects, can be arranged in a well-balanced manner on the rod guide and the bottom cover of the cylinder, the weight balance is good, and it is also possible to prevent a large load from being applied only to one of the vibration-damping rubbers provided on the bracket.

[0014] Furthermore, the control valve in the cylinder device can also have: a damping passage and a pressure relief passage that are provided on the cover member and are arranged in parallel in the middle of the discharge passage; a control valve body that is disposed on the damping passage and opens and closes the damping passage; a switching valve body that opens and closes the pressure relief passage; a first spring that biases the control valve body in a direction to close the damping passage; a second spring that biases the switching valve body in the same direction as the first spring and in a direction to open the pressure relief passage; and a third solenoid that resists the acting forces of the first spring and the second spring and applies a thrust to the control valve body via the switching valve body. According to the cylinder device configured in this way, not only can the damping force or the thrust be adjusted, but also the damping force in case of a failure can be set to a predetermined magnitude.

[0015] Effects of the Invention

[0016] According to the cylinder device of the present invention, the number of components can be reduced and the device can be miniaturized, and at the same time, there is no need to worry about liquid leakage to the outside. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a longitudinal sectional view of the cylinder device in the first embodiment of the present invention.

[0018] Figure 2 is a schematic view showing a state in which the cylinder device of the present invention is applied to a railway vehicle.

[0019] Figure 3 is a longitudinal sectional view of the cylinder device in the second embodiment of the present invention.

[0020] Figure 4 is a longitudinal sectional view of the cylinder device in the third embodiment of the present invention.

[0021] Figure 5 is a longitudinal sectional view of the cylinder device in the fourth embodiment of the present invention.

[0022] Figure 6 This is an example of the circuit diagram of the control valve in the cylinder device of the present invention.

[0023] Explanation of Reference Signs

[0024] 1. Cylinder; 2. Rod guide (cover member); 3. Piston; 4. Rod; 5. Rectifying passage; 6. Suction passage; 7. First passage; 8. First switching valve; 8a. First solenoid; 8b. First valve body; 9. Second passage; 10. Second switching valve; 10a. Second solenoid; 10b. Second valve body; 11. Discharge passage; 12. Control valve; 12a, 36. Third solenoid; 12b, 32. Control valve body; 16. Bottom cover; 23. Bottom cover (cover member); 24. Rod guide; 30. Damping passage; 31. Pressure relief passage; 33. Switching valve body; 34. First spring; 35. Second spring; C, C1, C2, C3. Cylinder device; M. Motor; P. Pump; S. Supply passage; R1. Rod side chamber; R2. Piston side chamber; T. Liquid storage tank. Detailed implementation mode

[0025] Hereinafter, the present invention will be described based on the embodiments shown in the drawings. In the cylinder devices C, C1, C2, C3 of the embodiments described below, the same reference numerals are assigned to the same components, and the description will be repeated. Therefore, for the same components that have been described in one embodiment, their detailed descriptions will be omitted in the descriptions of other embodiments.

[0026] As Figure 1 shown, the cylinder device C of the first embodiment is a shock absorber for suppressing the left - right movement of the body B of a railway vehicle. As Figure 1 shown, the cylinder device C includes: a cylinder 1; an annular rod guide 2 provided at one end of the cylinder 1 and serving as a cover member for closing the end of the cylinder 1; a piston 3 slidably inserted into the cylinder 1; a rod 4 inserted into the cylinder 1 and connected to the piston 3; a rod side chamber R1 and a piston side chamber R2 divided in the cylinder 1 by the piston 3; a liquid storage tank T for storing hydraulic oil; a rectifying passage 5 that only allows hydraulic oil to flow from the piston side chamber R2 to the rod side chamber R1; a suction passage 6 that only allows hydraulic oil to flow from the liquid storage tank T to the piston side chamber R2; a first passage 7 connecting the rod side chamber R1 and the piston side chamber R2; a first switching valve 8 provided in the middle of the first passage 7; a second passage 9 connecting the piston side chamber R2 and the liquid storage tank T; a second switching valve 10 provided in the middle of the second passage 9; a discharge passage 11 connecting the rod side chamber R1 and the liquid storage tank T; and a control valve 12 provided in the middle of the discharge passage 11.

[0027] Moreover, if Figure 2 As shown, this cylinder device C is inserted between the bogie W and the vehicle body B of the railway vehicle, and serves as a shock absorbing device of the vehicle body B for suppressing the vibration of the vehicle body B in the horizontal lateral direction relative to the vehicle running direction.

[0028] The following will describe in detail the various parts of the cylinder device C. The cylinder 1 is cylindrical. Figure 1 The left end of the cylinder 1 is closed by the rod guide 2 as a cover member. Figure 1 The other end of the rod guide 2, which is the right end, is fitted with a valve housing 13. A rod 4 is inserted through the inner periphery of the rod guide 2, and the rod is inserted into the cylinder 1 so as to be movably disposed. The rod guide 2 is in sliding contact with the outer periphery of the rod 4, and guides the axial movement of the rod 4 relative to the cylinder 1. One end of the rod 4 protrudes to the outside of the cylinder 1, and the other end of the rod 4 is connected to the piston 3 which is inserted into the cylinder 1 so as to be slidable.

[0029] An outer cylinder 14 covering the outer periphery of the cylinder 1 is provided on the outer periphery of the cylinder 1. The outer cylinder 14 includes a cylinder portion 14a and a Figure 1 The outer cylinder 14 has a flange portion 14b at the left end. In addition, the outer cylinder 14 has a plurality of threaded holes 14c opening from the left end of the flange portion 14b. In addition, the cylinder portion 14a and the flange portion 14b may be joined by a joining method other than welding. Figure 1 At the middle left end, an annular head cap 15 is fastened by a plurality of bolts 20. Furthermore, the rod guide 2 is fastened to the head cap 15 by a plurality of bolts 21. Figure 1 The right end of the bottom cover 16 is installed, and the bottom cover is used to close the outer cylinder 14 in Figure 1 The right end of .

[0030] In this way, the cylinder 1 and the valve housing 13 engaged with the end of the cylinder 1 are clamped by the head cap 15 and the bottom cover 16 connected to the outer cylinder 14, and are kept fixed relative to the outer cylinder 14. Figure 1 The left end of the rod guide 2 and the head cap 15 are closed, and the outer tube 14 is Figure 1 The right end of the cylinder 1 is closed by the bottom cover 16, and the annular gap between the cylinder 1 and the outer tube 14 is sealed. Moreover, the liquid storage tank T is formed by the annular gap between the cylinder 1 and the outer tube 14.

[0031] In this embodiment, the bottom cover 16 is not directly engaged with the cylinder 1, but is connected to the cylinder 1 via the valve housing 13 by being mounted on the other end of the cylinder portion 14a of the outer cylinder 14. In this way, the bottom cover 16 can be connected to the cylinder 1 indirectly in addition to being directly engaged with the cylinder 1.

[0032] Further, the outer periphery of the rod 4 is sealed by a sealing member 22a installed at the left end in Figure 1 and is sealed within the cylinder 1. Further, the cylinder 1 is divided by a piston 3 slidably inserted therein into Figure 1 a rod-side chamber R1 on the left side in Figure 1 and a piston-side chamber R2 on the right side in Figure 1 . A liquid such as hydraulic oil is filled in the rod-side chamber R1 and the piston-side chamber R2, and a liquid and a gas are filled in the liquid reservoir tank T. In addition, the liquid used in the cylinder device C may also be a liquid other than hydraulic oil, such as water or an aqueous solution. Moreover, at the left end of Figure 1 which is the front end of the rod 4, a bracket 4a connectable to the bogie W of the railway vehicle is provided.

[0033] Next, a rectifying passage 5 is provided on the piston 3. The rectifying passage 5 communicates the piston-side chamber R2 and the rod-side chamber R1 and has a check valve 5a in the middle. The check valve 5a only allows the hydraulic oil to flow from the piston-side chamber R2 to the rod-side chamber R1, and the rectifying passage 5 is set as a one-way passage that only allows the hydraulic oil to flow from the piston-side chamber R2 to the rod-side chamber R1.

[0034] As described above, the valve housing 13 is fitted into the end of the cylinder 1 and closes the right end of the cylinder 1 in Figure 1 . Moreover, the valve housing 13 has a through hole 13a provided in the center, and a suction passage 6 that communicates the liquid reservoir tank T and the piston-side chamber R2 and has a check valve 6a in the middle. An axially extending shaft portion 13b is provided at the center of the right end of the valve housing 13. The through hole 13a opens from the front end of the shaft portion 13b and communicates with the piston-side chamber R2 through the left end of the valve housing 13. The suction passage 6 communicates with the left end of the valve housing 13 from a position at the right end of the valve housing 13 and avoiding the shaft portion 13b. In addition, the check valve 6a only allows the hydraulic oil to flow from the liquid reservoir tank T to the piston-side chamber R2, and the suction passage 6 is set as a one-way passage that only allows the hydraulic oil to flow from the liquid reservoir tank T to the piston-side chamber R2.

[0035] The bottom cover 16 is attached to one end at the right end of the outer cylinder 14 and closes one end of the outer cylinder 14. The bottom cover 16 includes: a bracket 16a that can be connected to the other of the bogie W and the body B of the railway vehicle provided at the right end in Figure 1 ; a cylindrical fitting portion 16b provided at the left end in Figure 1 and fitted to the outer cylinder 14; a recess 16c that fits with the right end of the cylinder 1 and the valve housing 13; and a fitting hole 16d located at the left end in Figure 1 and opening on the outer peripheral side more than the recess 16c, and into which a conduit 17 can be inserted. Moreover, as Figure 1 in Figure 2As shown, the cylinder device C is connected to the body B and the bogie W of the railway vehicle by means of these brackets 4a and 16a, and is inserted between the bogie W and the body B.

[0036] When the fitting portion 16b of the bottom cover 16 configured in this way is fitted to the right end of the outer cylinder 14, a groove is formed between the fitting portion 16b and the right end of the cylindrical portion 14a of the outer cylinder 14, and the two are welded together using this groove. In addition, the joining of the outer cylinder 14 and the bottom cover 16 can also be carried out by a joining method other than welding. The concave portion 16c includes: a large-diameter portion 16c1 whose inner diameter is larger than the outer diameters of the valve housing 13 and the cylinder 1; a medium-diameter portion 16c2 which is connected to the right end of the large-diameter portion 16c1 and whose inner diameter is smaller than that of the large-diameter portion 16c1; and a small-diameter portion 16c3 which is connected to the right end of the medium-diameter portion 16c2 and whose inner diameter is smaller than that of the medium-diameter portion 16c2. When the end of the cylinder 1 in which the valve housing 13 is fitted is inserted into this concave portion 16c, the shaft portion 13b of the valve housing 13 is inserted into the small-diameter portion 16c3 to position the cylinder 1 and the valve housing 13 in the radial direction. In addition, the medium-diameter portion 16c2 is smaller than the outer diameter of the valve housing 13. When the cylinder 1 and the valve housing 13 are inserted into the large-diameter portion 16c1, the valve housing 13 is seated on the stepped portion between the large-diameter portion 16c1 and the medium-diameter portion 16c2, and an annular gap G is formed on the right side of the valve housing 13. This annular gap G communicates with the liquid storage tank T through a groove 16c4 provided in the bottom cover 16. In addition, this annular gap G faces the suction passage 6 provided in the valve housing 13. Therefore, the suction passage 6 communicates with the liquid storage tank T through the gap G and the groove 16c4, and ensures the communication between the piston-side chamber R2 and the liquid storage tank T. In addition, in the liquid storage tank T, in addition to hydraulic oil, gas is also filled. It is not necessary to fill the liquid storage tank T with compressed gas to bring it to a pressurized state.

[0037] In addition, a passage 16e that opens from the fitting hole 16d to the small-diameter portion 16c3 of the concave portion 16c is provided in the bottom cover 16. In addition, the passage 16e communicates with the piston-side chamber R2 through the through hole 13a of the valve housing 13, and makes the fitting hole 16d communicate with the piston-side chamber R2.

[0038] Next, the head cap 15 is annular and includes: a fitting portion 15a that fits with the cylinder 1, which is provided with a large diameter on the right end side of the inner circumference; a flange portion 15b that is provided opposite to the flange portion 14b of the outer cylinder 14 provided on the outer circumference; a fitting hole 15c that opens axially at a position opposite to the fitting hole 16d of the bottom cover 16 at the right end; a passage 15d that extends from the fitting hole 15c and leads to Figure 1 the left end in ; and a passage 15e that extends from Figure 1 the right end; and a passage 15e that extends from Figure 1 the left end; and a passage 15e that extends from Figure 1from the left end to the right end therein. A plurality of threaded holes (not shown) are provided in the flange portion 14b of the outer cylinder 14, and a plurality of holes (not shown) are provided at positions opposite to the threaded holes of the flange portion 15b of the head cap 15. Further, the head cap 15 is fixed to the outer cylinder 14 by butting the flange portion 15b against the flange portion 14b of the outer cylinder 14 and fastening the flange portions 14b and 15b to each other with a plurality of bolts 20.

[0039] In the fitting hole 15c of the head cap 15 and the fitting hole 16d of the bottom cover 16 provided opposite to the fitting hole 15c, a conduit 17 is fitted in a sealed state. Therefore, the passage 15d communicating with the fitting hole 15c communicates with the piston side chamber R2 via the inside of the conduit 17, the passage 16e, and the through hole 13a. In addition, the passage 15e communicates with the liquid storage tank T.

[0040] Further, the conduit 17 is held by the head cap 15 and the bottom cover 16 fixed to the outer cylinder 14, so that even if vibration is input to the cylinder device C, it will not fall off.

[0041] In the present embodiment, the rod guide 2 as a lid member is fastened to the head cap 15 by bolts 21. The rod guide 2 includes: a lid portion 2a having a fitting portion 2a1 fitted to the inner periphery of the cylinder 1, connected to the head cap 15 and closing the left end of the cylinder 1 Figure 1 therein; and a valve holding portion 2b connected to the side of the lid portion 2a and holding the first solenoid 8a of the first switching valve 8, the second solenoid 10a of the second switching valve 10, and the third solenoid 12a of the control valve 12; wherein, it is formed as an integral part that cannot be disassembled.

[0042] The lid portion 2a is provided with a rod insertion hole 2a2 that penetrates from Figure 1 the left end therein to the right end of the fitting portion 2a1 Figure 1 therein. A bushing 19 in a cylindrical shape and in sliding contact with the outer periphery of the rod 4 is mounted on the inner periphery of the rod insertion hole 2a2. Although not shown in the figure, the lid portion 2a is provided with a plurality of bolt insertion holes that are provided opposite to a plurality of threaded holes (not shown) provided in the head cap 15 and allow the bolts 21 to pass through. Further, a ring-shaped seal housing 22 for holding a ring-shaped seal member 22a in sliding contact with the outer periphery of the rod 4 is laminated on the left end of the rod guide 2 Figure 1 therein. The seal housing 22 is also provided with a plurality of bolt insertion holes that are provided opposite to a plurality of threaded holes (not shown) provided in the head cap 15 and allow the bolts 21 to pass through. Therefore, the rod guide 2 and the seal housing 22 are laminated on the head cap 15, and while the bolts 21 are inserted into the bolt insertion holes of the rod guide 2 and the seal housing 22, they are screwed into the threaded holes of the head cap 15, thereby fixing the rod guide 2 and the seal housing 22 to the head cap 15.

[0043] The fitting portion 2a1 of the rod guide 2 is annular and has a groove 2a3 communicating with the rod side chamber R1 on a part of its outer periphery. The rod guide 2 also has passages 2c, 2d, 2e inside the cover portion 2a and the valve holding portion 2b.

[0044] The passage 2c extends from the groove 2a3 in the rod guide 2. Figure 1 The right end of the opening is connected to the channel 15d of the head cap 15. Moreover, the first switch valve 8 is provided on the channel 2c.

[0045] The passage 2d is connected to a connection point P1 that is closer to the passage 15d side than the first on-off valve 8 of the passage 2c, and is connected to the rod guide 2 at the connection point P1. Figure 1 The right end of the channel 2c is opened so that the channel 2c is connected to the channel 15e of the head cap 15. Moreover, a second switch valve 10 is provided on the channel 2d.

[0046] Furthermore, the channel 2e is connected to a connection point P2 closer to the groove 2a3 side than the first switch valve 8 of the channel 2c and a connection point P3 closer to the channel 15e side than the second switch valve 10 of the channel 2d, and the channel 2c and the channel 2d are communicated. Moreover, a control valve 12 is provided in the channel 2d.

[0047] One end side of the channel 2c is communicated with the rod side chamber R1 via the groove 2a3, and the other end side is communicated with the piston side chamber R2 via the channel 15d, the inside of the conduit 17, the channel 16e, and the through hole 13a. Moreover, the first channel 7 is formed by the groove 2a3, the channel 2c, the channel 15d, the inside of the conduit 17, the channel 16e, and the through hole 13a, and communicates the rod side chamber R1 and the piston side chamber R2. In addition, since the first switch valve 8 is provided on the channel 2c, it is provided in the middle of the first channel 7.

[0048] One end side of the channel 2d communicates with the piston side chamber R2 via a portion closer to the channel 15d side than the connection point P1 of the channel 2c, the inside of the conduit 17, the channel 16e, and the through hole 13a without communicating with the first switch valve 8, and the other end side communicates with the reservoir tank T via the channel 15e. Furthermore, the second channel 9 is formed by the through hole 13a, the channel 16e, the inside of the conduit 17, the channel 15d, a portion of the channel 2c, the channel 2d, and the channel 15e, and communicates with the piston side chamber R2 and the reservoir tank T. In addition, since the second switch valve 10 is provided on the channel 2d, it is provided in the middle of the second channel 9.

[0049] One end side of the passage 2e communicates with the rod-side chamber R1 in a state where the first switching valve 8 is not connected, via a portion closer to the groove 2a3 side than the connection point P2 of the passage 2c and the groove 2a3. The other end side communicates with the liquid storage tank T in a state where it does not pass through the second switching valve 10, via a portion closer to the passage 15e side than the connection point P3 of the passage 2d and the passage 15e. Moreover, the discharge passage 11 is formed by the groove 2a3, a part of the passage 2c, the passage 2e, and the passage 15e, and communicates the rod-side chamber R1 and the liquid storage tank T. In addition, the control valve 12 is provided on the passage 2e, and thus it is provided in the middle of the discharge passage 11.

[0050] The first switching valve 8 is a switching valve that opens and closes the passage 2c which is a part of the first passage 7, and includes: a first solenoid 8a which is mounted on the outside of the rod guide 2 by a bolt (not shown); a first valve body 8b which is driven by the first solenoid 8a and is provided on the passage 2c, and has a cut-off position and a communication position; and a spring 8c which biases the first valve body 8b to the cut-off position. Moreover, when the first switching valve 8 energizes the first solenoid 8a to resist the force of the spring 8c and applies a thrust to the first valve body 8b, the first valve body 8b is in the communication position to open the first passage 7. When the first solenoid 8a is not energized, the first valve body 8b is in the cut-off position by the force of the spring 8c to close the first passage 7. In this way, the first switching valve 8 becomes a normally closed type switching valve. Other components of the first switching valve 8 except the first solenoid 8a are provided inside the rod guide 2.

[0051] The second switching valve 10 is a switching valve that opens and closes the passage 2d which is a part of the second passage 9, and includes: a second solenoid 10a which is mounted on the outside of the rod guide 2 by a bolt (not shown); a second valve body 10b which is driven by the second solenoid 10a and is provided on the passage 2d, and has a cut-off position and a communication position; and a spring 10c which biases the second valve body 10b to the cut-off position. Moreover, when the second switching valve 10 energizes the second solenoid 10a to resist the force of the spring 10c and applies a thrust to the second valve body 10b, the second valve body 10b is in the communication position to open the second passage 9. When the second solenoid 10a is not energized, the second valve body 10b is in the cut-off position by the force of the spring 10c to close the second passage 9. In this way, the second switching valve 10 becomes a normally closed type switching valve. Other components of the second switching valve 10 except the second solenoid 10a are provided inside the rod guide 2.

[0052] In the present embodiment, the control valve 12 is a variable relief valve that can adjust the opening pressure and is used to open and close the passage 2e that is part of the discharge passage 11. It includes: a third solenoid 12a that is mounted outside the rod guide 2 by a bolt (not shown); a control valve body 12b that is driven by the third solenoid 12a and is disposed on the passage 2e; a spring 12c that biases the control valve body 12b in the valve-closed direction; and a pilot passage 12d that causes the pressure in the rod-side chamber R1 to act on the control valve body 12b in the valve-opening direction. Moreover, the third solenoid 12a applies a thrust to the control valve body 12b in a direction opposite to the acting force of the spring 12c. On the control valve body 12b, the thrust of the third solenoid 12a and the pressure in the rod-side chamber R1 are applied in the valve-opening direction, and the acting force of the spring 12c is applied in the valve-closed direction. When adjusting the amount of current applied to the third solenoid 12a, the magnitude of the thrust of the third solenoid 12a can be adjusted. Therefore, by adjusting the amount of current applied to the third solenoid 12a, the opening pressure when the control valve 12 opens the discharge passage 11 can be adjusted. The components of the control valve 12 other than the third solenoid 12a are disposed inside the rod guide 2. In addition to the variable relief valve, the control valve 12 can also be a valve that can adjust the resistance applied to the flow of hydraulic oil.

[0053] In addition, the first solenoid 8a, the second solenoid 10a, and the third solenoid 12a are mounted in parallel with the cylinder 1 on the cylinder-side end surface of the rod guide 2 that is a cover member. In this way, when the first solenoid 8a, the second solenoid 10a, and the third solenoid 12a are mounted on the rod guide 2 that is a cover member, the first solenoid 8a, the second solenoid 10a, and the third solenoid 12a do not interfere with the axial movement of the rod 4 relative to the cylinder 1, and an increase in the size of the cylinder device C in the radial direction can be avoided.

[0054] In the cylinder device C configured in this way, when the first switching valve 8 is in the connected position and the second switching valve 10 is in the cut-off position, the rod-side chamber R1 and the piston-side chamber R2 are in a connected state via the first passage 7, while the connection between the piston-side chamber R2 and the liquid storage tank T via the second passage 9 is cut off. In this state, when the cylinder device C exhibits an extending action in which the rod 4 retracts relative to the cylinder 1 by an external input, the hydraulic oil moves from the shrinking rod-side chamber R1 through the first passage 7 to the expanding piston-side chamber R2. In addition, within the entire cylinder 1, the hydraulic oil in the volume portion where the rod 4 retracts from the cylinder 1 is insufficient, and the insufficient hydraulic oil opens the check valve 6a and moves from the liquid storage tank T to the piston-side chamber R2 through the suction passage 6. In this way, in the state where the first switching valve 8 is in the connected position and the second switching valve 10 is in the cut-off position, even when the cylinder device C performs an extending action, the hydraulic oil does not flow through the control valve 12 provided in the discharge passage 11. Since the rod-side chamber R1 and the piston-side chamber R2 are almost at the liquid storage tank pressure, the cylinder device C does not generate a damping force on the extending side that hinders the extending action.

[0055] On the other hand, in the state where the first switching valve 8 is in the connected position and the second switching valve 10 is in the cut-off position, when the cylinder device C exhibits a contracting action, the hydraulic oil moves from the shrinking piston-side chamber R2 to the expanding rod-side chamber R1 after passing through the first passage 7. In addition, within the entire cylinder 1, the hydraulic oil in the volume portion where the rod 4 enters the cylinder 1 is excessive. Since the second passage 9 is cut off, the excessive hydraulic oil in the cylinder 1 moves from the inside of the cylinder 1 to the liquid storage tank T through the control valve 12 in the discharge passage 11. In this way, in the state where the first switching valve 8 is in the connected position and the second switching valve 10 is in the cut-off position, when the cylinder device C performs a contracting action, the hydraulic oil flows through the control valve 12 provided in the discharge passage 11, and the overall pressure in the cylinder 1 rises. Therefore, the cylinder device C generates a damping force on the compression side that hinders the contracting action. Since the magnitude of the pressure in the cylinder 1 can be adjusted by adjusting the opening pressure of the control valve 12, the damping force on the compression side generated by the cylinder device C can be adjusted by adjusting the amount of electric current applied to the third solenoid 12a of the control valve 12. The damping force on the compression side generated by the cylinder device C at this time is the damping force obtained by multiplying the difference between the pressure-receiving area on the piston-side chamber R2 side of the piston 3 and the pressure-receiving area of the rod-side chamber R1 by the pressure in the cylinder 1.

[0056] In addition, in the cylinder device C, when the first switching valve 8 is in the cut-off position and the second switching valve 10 is in the communication position, the communication between the rod-side chamber R1 and the piston-side chamber R2 via the first passage 7 is cut off, and the piston-side chamber R2 and the liquid storage tank T communicate via the second passage 9. In this state, when the cylinder device C exhibits an extending action in which the rod 4 retracts relative to the cylinder 1 due to an external input, since the first passage 7 is cut off, the hydraulic oil moves from the shrinking rod-side chamber R1 to the liquid storage tank T after passing through the control valve 12 of the discharge passage 11. The hydraulic oil is supplied to the piston-side chamber R2 that expands due to the extending action of the cylinder device C after flowing through the second passage 9 from the liquid storage tank T. In this way, in the state where the first switching valve 8 is in the cut-off position and the second switching valve 10 is in the communication position, when the cylinder device C performs an extending action, the hydraulic oil flows through the control valve 12 provided in the discharge passage 11, and the pressure in the rod-side chamber R1 rises. On the other hand, since the pressure in the piston-side chamber R2 is almost the liquid storage tank pressure, the cylinder device C generates a damping force on the extending side that hinders the extending action. Since the magnitude of the pressure in the rod-side chamber R1 can be adjusted by adjusting the opening pressure of the control valve 12, the damping force on the extending side generated by the cylinder device C can be adjusted by adjusting the amount of electric current applied to the third solenoid 12a of the control valve 12. The damping force on the extending side generated by the cylinder device C at this time is the damping force of the value obtained by multiplying the pressure receiving area of the rod-side chamber R1 of the piston 3 by the pressure in the cylinder 1.

[0057] On the other hand, in the state where the first switching valve 8 is in the cut-off position and the second switching valve 10 is in the communication position, when the cylinder device C exhibits a contracting action, the hydraulic oil pushes open the check valve 5a and moves from the shrinking piston-side chamber R2 to the expanding rod-side chamber R1 after flowing through the rectifying passage 5. In addition, in the entire cylinder 1, the hydraulic oil in the volume part where the rod 4 enters the cylinder 1 is excessive, and the excessive hydraulic oil in the cylinder 1 moves from the cylinder 1 to the liquid storage tank T through the second passage 9. In this way, in the state where the first switching valve 8 is in the cut-off position and the second switching valve 10 is in the communication position, even when the cylinder device C performs a contracting action, the hydraulic oil does not flow through the control valve 12 provided in the discharge passage 11. Since the rod-side chamber R1 and the piston-side chamber R2 are almost at the liquid storage tank pressure, the cylinder device C does not generate a damping force on the compression side that hinders the contracting action.

[0058] As described above, the damping force on the compression side of the cylinder device C is the damping force obtained by multiplying the difference between the pressure-receiving area on the piston-side chamber R2 side of the piston 3 and the pressure-receiving area of the rod-side chamber R1 by the pressure in the cylinder 1, and the damping force on the extension side generated by the cylinder device C is the damping force obtained by multiplying the pressure-receiving area of the rod-side chamber R1 of the piston 3 by the pressure in the cylinder 1. In the cylinder device C of the present embodiment, the pressure-receiving area on the rod-side chamber R1 side of the piston 3 is set to be half of the pressure-receiving area on the piston-side chamber R2 side. Therefore, if the valve opening pressure of the control valve 12 is the same, the cylinder device C can make the damping force on the extension side and the damping force on the compression side equal. Therefore, if the pressure-receiving area on the rod-side chamber R1 side of the piston 3 is set to be half of the pressure-receiving area on the piston-side chamber R2 side, the damping force of the cylinder device C can be easily controlled.

[0059] As described above, when the first switching valve 8 is in the communication position and the second switching valve 10 is in the cut-off position, the cylinder device C generates a damping force only during the contraction operation and does not generate a damping force during the extension operation. In addition, when the first switching valve 8 is in the cut-off position and the second switching valve 10 is in the communication position, the cylinder device C generates a damping force only during the extension operation and does not generate a damping force during the contraction operation.

[0060] When Figure 2In a state where the shown cylinder device C is installed on a railway vehicle, when the vehicle body B moves rightward relative to the bogie W, and when the cylinder device C exhibits a contraction action and the vehicle body B moves leftward relative to the bogie W, the cylinder device C exhibits an extension action. In this case, the cylinder device C 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 the bogie W move rightward and the moving speed of the bogie W is slower than that of the vehicle body B, it performs a contraction action to generate the damping force on the compression side and can suppress 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 faster than that of the vehicle body B, the cylinder device C does not perform a contraction action but exhibits an extension action. Here, when the cylinder device C generates the damping force on the extension side, since the extension action of the cylinder device C is suppressed, the rightward movement of the bogie W is transmitted to the vehicle body B. However, in the cylinder device C of the present embodiment, since it can function as a semi-active shock absorber with a unilateral effect, it can be controlled so that only the damping force on the compression side is generated when the vehicle body B and the bogie W move rightward and the moving speed of the bogie W is faster than that of the vehicle body B, thereby preventing the promotion of the vibration of the vehicle body B. In addition, when the vehicle body B and the bogie W move leftward and the moving speed of the bogie W is faster than that of the vehicle body B, it is only necessary to control it to generate only the damping force on the extension side of the cylinder device C. In this way, when the direction in which the cylinder device C generates the damping force is a direction in which the vibration of the bogie W of the railway vehicle strengthens the vibration of the vehicle body B, the cylinder device C functions as a shock absorber with a unilateral effect so that no force is generated in this direction. Therefore, this cylinder device C can easily achieve semi-active control according to the Carnop theory and can thus function as a semi-active shock absorber.

[0061] Next, when both the first switching valve 8 and the second switching valve 10 are in the cut-off position, the communication between the rod-side chamber R1 and the piston-side chamber R2 via the first passage 7 is cut off, and the communication between the piston-side chamber R2 and the liquid storage tank T via the second passage 9 is cut off. In this state, when the cylinder device C exhibits an extending action in which the rod 4 retracts relative to the cylinder 1 due to an external input, since the first passage 7 is cut off, the hydraulic oil moves from the shrinking rod-side chamber R1 to the liquid storage tank T after passing through the control valve 12 of the discharge passage 11. In the piston-side chamber R2 that expands due to the extending action of the cylinder device C, the check valve 6a opens, and hydraulic oil is supplied from the liquid storage tank T through the suction passage 6. In this way, in a state where both the first switching valve 8 and the second switching valve 10 are in the cut-off position, when the cylinder device C performs an extending action, the hydraulic oil flows through the control valve 12 provided in the discharge passage 11, and the pressure in the rod-side chamber R1 rises. On the other hand, since the pressure in the piston-side chamber R2 is almost the liquid storage tank pressure, the cylinder device C generates a damping force on the extending side that hinders the extending action. Since the magnitude of the pressure in the rod-side chamber R1 can be adjusted by adjusting the opening pressure of the control valve 12, the damping force on the extending side generated by the cylinder device C can be adjusted by adjusting the amount of electric current applied to the third solenoid 12a of the control valve 12.

[0062] On the other hand, in a state where both the first switching valve 8 and the second switching valve 10 are in the cut-off position, when the cylinder device C exhibits a contracting action, the hydraulic oil pushes open the check valve 5a and moves from the shrinking piston-side chamber R2 to the expanding rod-side chamber R1 via the rectifying passage 5. In addition, in the entire cylinder 1, the hydraulic oil in the volume part where the rod 4 enters the cylinder 1 is excessive. Since the second passage 9 is cut off, the excessive hydraulic oil in the cylinder 1 moves from the inside of the cylinder 1 to the liquid storage tank T through the control valve 12 of the discharge passage 11. In this way, in a state where both the first switching valve 8 and the second switching valve 10 are in the cut-off position, when the cylinder device C performs a contracting action, the hydraulic oil flows through the control valve 12 provided in the discharge passage 11, and the overall pressure in the cylinder 1 rises. Therefore, the cylinder device C generates a damping force on the compression side that hinders the contracting action. Since the magnitude of the pressure in the cylinder 1 can be adjusted by adjusting the opening pressure of the control valve 12, the damping force on the compression side generated by the cylinder device C can be adjusted by adjusting the amount of electric current applied to the third solenoid 12a of the control valve 12.

[0063] As described above, when both the first switching valve 8 and the second switching valve 10 are in the cut-off position and the cylinder device C expands and contracts, the hydraulic oil circulates unidirectionally in the liquid storage tank T, the piston side chamber R2, and the rod side chamber R1 and flows through the control valve 12. Therefore, the cylinder device C can function as a unidirectional passive shock absorber, which generates damping forces during both the extending action and the contracting action, and the damping force can be adjusted by adjusting the opening pressure of the control valve 12. In addition, 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, if the opening pressure of the control valve 12 is the same, the cylinder device C can make the damping force on the extending side and the damping force on the compressing side equal.

[0064] Furthermore, in the cylinder device C, when both the first switching valve 8 and the second switching valve 10 are in the connected position, the rod side chamber R1 and the piston side chamber R2 are connected via the first passage 7, and the piston side chamber R2 and the liquid storage tank T are connected via the second passage 9. In this state, when the cylinder device C shows an extending action in which the rod 4 retracts relative to the cylinder 1 by an external input, the hydraulic oil moves from the shrinking rod side chamber R1 through the first passage 7 to the expanding piston side chamber R2. In addition, within the entire cylinder 1, the hydraulic oil in the volume part where the rod 4 retracts from the cylinder 1 is insufficient, and the insufficient hydraulic oil moves from the liquid storage tank T to the piston side chamber R2 through the second passage 9. In this way, when both the first switching valve 8 and the second switching valve 10 are in the connected position, even if the cylinder device C performs an extending action, the hydraulic oil does not flow through the control valve 12 provided in the discharge passage 11, and since the rod side chamber R1 and the piston side chamber R2 are almost at the liquid storage tank pressure, the cylinder device C does not generate a damping force on the extending side that hinders the extending action.

[0065] On the other hand, in the state where both the first switching valve 8 and the second switching valve 10 are in the connected position, when the cylinder device C shows a contracting action, the hydraulic oil moves from the shrinking piston side chamber R2 to the expanding rod side chamber R1 after passing through the first passage 7. In addition, within the entire cylinder 1, the hydraulic oil in the volume part where the rod 4 enters the cylinder 1 is excessive, and the excessive hydraulic oil in the cylinder 1 moves from the inside of the cylinder 1 to the liquid storage tank T through the second passage 9. In this way, in the state where both the first switching valve 8 and the second switching valve 10 are in the connected position, even if the cylinder device C performs a contracting action, the hydraulic oil does not flow through the control valve 12 provided in the discharge passage 11, and since the rod side chamber R1 and the piston side chamber R2 are almost at the liquid storage tank pressure, the cylinder device C does not generate a damping force on the compressing side that hinders the contracting action.

[0066] As described above, when both the first switching valve 8 and the second switching valve 10 are in the communicating position, the cylinder device C is in an unloaded state where no damping force is generated during both the extending operation and the contracting operation.

[0067] As described above, the cylinder device C in the present embodiment includes: a cylinder 1; a rod guide member (cover member) 2 provided at one end of the cylinder 1 to close the end of the cylinder 1; a piston 3 slidably inserted into the cylinder 1; a rod 4 inserted into the cylinder 1 and connected to the piston 3; a rod-side chamber R1 and a piston-side chamber R2 formed in the cylinder 1 by partitioning with the piston 3; a liquid storage tank T for storing hydraulic oil (liquid); a rectifying passage 5 that only allows the hydraulic oil (liquid) to flow from the piston-side chamber R2 to the rod-side chamber R1; a suction passage 6 that only allows the hydraulic oil (liquid) to flow from the liquid storage tank T to the piston-side chamber R2; a first passage 7 that connects the rod-side chamber R1 and the piston-side chamber R2; a first switching valve 8 provided in the middle of the first passage 7; a second passage 9 that connects the piston-side chamber R2 and the liquid storage tank T; a second switching valve 10 provided in the middle of the second passage 9; a discharge passage 11 that connects the rod-side chamber R1 and the liquid storage tank T; and a control valve 12 provided in the middle of the discharge passage 11. Among them, the first switching valve 8 has a first valve body 8b provided in the rod guide member (cover member) 2 for switching the first passage 7, and a first solenoid 8a mounted on the rod guide member (cover member) 2 for driving the first valve body 8b; the second switching valve 10 has a second valve body 10b provided in the rod guide member (cover member) 2 for switching the second passage 9, and a second solenoid 10a mounted on the rod guide member (cover member) 2 for driving the second valve body 10b; the control valve 12 has a control valve body 12b provided in the rod guide member (cover member) 2 for switching the discharge passage 11, and a third solenoid 12a provided in the rod guide member (cover member) 2 for applying a thrust to the control valve body 12b.

[0068] In the cylinder device C configured in this manner, the first valve body 8b of the first switching valve 8, the second valve body 10b of the second switching valve 10, and the control valve body 12b of the control valve 12 are built in a rod guide (cover member) 2 as a single component. Therefore, in the cylinder device C of the present embodiment, it is not necessary to fix the valve blocks constituting the first switching valve, the valve blocks constituting the second switching valve, and the valve blocks constituting the control valve to the rod guide (cover member) 2 with bolts respectively. When adopting a structure for fastening each valve block to the rod guide (cover member) 2 with bolts, it is necessary to fasten the first, second, and third spiral tubes to each valve block with bolts, and the number of bolt fastening parts becomes very large. Moreover, it is necessary to take the following measures, that is, to set the natural frequency of each valve block and the total natural frequency including the rod guide (cover member) 2 and the valve blocks to be above the natural frequency of the railway vehicle to prevent the bolts from falling off, and in order to ensure the fitting length of the bolts, the design constraints of each valve block and the rod guide (cover member) 2 increase, and the degree of freedom in material selection is significantly limited due to the problem of vibration frequency. In contrast, as described above, in the cylinder device C of the present embodiment, since the first valve body 8b of the first switching valve 8, the second valve body 10b of the second switching valve 10, and the control valve body 12b of the control valve 12 are built in the rod guide (cover member) 2 as a single component, the number of bolt fastening parts can be reduced, and the degree of freedom in material selection of the rod guide (cover member) 2 can be improved. For example, a lightweight metal such as aluminum can be used to form the rod guide (cover member) 2. In addition, since it is not necessary to connect each valve block to the rod guide (cover member) 2, there is no need to worry about leakage of hydraulic oil (liquid) from between the rod guide (cover member) 2 and each valve block. Therefore, according to the cylinder device C of the present embodiment, since the number of bolt fastening parts can be reduced without the valve blocks, the number of components can be reduced and the device can be miniaturized, and there is no need to worry about leakage of hydraulic oil (liquid) to the outside. In addition, according to the cylinder device C of the present embodiment, since it is not necessary to connect the valve blocks to the side of the rod guide (cover member) 2, the thickness of the portion of the rod 4 for supporting the rod guide (cover member) 2 can be limited to the minimum required for the thickness because the degree of freedom in design is improved.

[0069] In addition, when the cover member is used as the rod guide 2, since the first switching valve 8, the second switching valve 10, and the control valve 12 as heavy objects are concentrated on the rod guide 2, the center of gravity of the cylinder device C is located near the rod guide 2, so that the weight balance of the cylinder device C is improved, and it is also possible to prevent an offset load from being applied only to one of the vibration-proof rubbers V1, V2 of the brackets 4a, 16a on both ends of the cylinder device C.

[0070] In addition, in the foregoing content, although the cover member is used as the rod guide 2, it may also be asFigure 3 Like the cylinder device C1 in the second embodiment shown, with the bottom cover 23 as the cover member, the first solenoid 8a, the second solenoid 10a, and the third solenoid 12a are mounted on the bottom cover 23, and the first valve body 8b of the first switching valve 8, the second valve body 10b of the second switching valve 10, and the control valve body 12b of the control valve 12 are built in the bottom cover 23. The cylinder device C1 in the second embodiment is a shock absorber for suppressing the left - right movement of the body B of a railway vehicle. In addition, as Figure 3 shown, the only differences between the cylinder device C1 in the second embodiment and the cylinder device C in the first embodiment are the bottom cover 23 and the rod guide 24.

[0071] The bottom cover 23 is mounted on one end of the right end of the outer cylinder 14 in Figure 3 and closes one end of the outer cylinder 14. The bottom cover 23 has: a cover portion 23a that fits into the right end of the outer cylinder 14 in Figure 3 and is used to close the right end of the outer cylinder 14; a valve holding portion 23b that is connected to the side of the cover portion 23a and is used to hold the first solenoid 8a in the first switching valve 8, the second solenoid 10a of the second switching valve 10, and the third solenoid 12a in the control valve 12; and a bracket 23c that is provided at the right end of the cover portion 23a in Figure 3 ; among them, at least the cover portion 23a and the valve holding portion 23b are formed as an inseparable one - piece component.

[0072] The cover portion 23a has: a concave portion 23a1 that fits with the right end of the cylinder 1 of the valve housing 13 and the valve housing 13; and a fitting hole 23a2 that is located at the Figure 3 left end in and opens on the outer peripheral side from the concave portion 23a1, and the conduit 17 can be inserted into the Figure 2 right end in. In addition, a gap G formed on the outer periphery of the shaft portion 13b of the valve housing 13 in the concave portion 23a1 communicates with the liquid storage tank T.

[0073] Moreover, the bottom cover 23 also has channels 23d, 23e, 23f inside the cover portion 23a and the valve holding portion 23b.

[0074] The channel 23d opens at the right end of the fitting hole 23a2 of the bottom cover 23 in Figure 3 and communicates with the deepest part where the shaft portion 13b is fitted in the concave portion 23a1, and at the same time communicates with the piston - side chamber R2 via the through - hole 13a. And a first switching valve 8 is provided on the channel 23d.

[0075] The channel 23e is connected to a side closer to the concave portion 23a1 than the first switching valve 8 of the channel 23d, communicates with the gap G in the concave portion 23a1, and at the same time communicates with the liquid storage tank T via the gap G. And a second switching valve 10 is provided on the channel 23e.

[0076] Further, the passage 23f is connected to a side closer to the catheter 17 than the first switching valve 8 of the passage 23d and a side closer to the liquid storage tank T than the second switching valve 10 of the passage 23e, and the passage 23d and the passage 23e are communicated. Moreover, a control valve 12 is provided in the passage 23f.

[0077] Next, the rod guide 24 is fastened to the head cap 15 by bolts 21. The rod guide 24 has a fitting portion 24a fitted to the inner periphery of the cylinder 1 and a rod insertion hole 24b penetrating through the left end in Figure 3 to the right end in Figure 3 of the fitting portion 24a, which is connected to the head cap 15 and closes the left end of the cylinder 1 in Figure 3 . Further, a bush 19 in a cylindrical shape and in sliding contact with the outer periphery of the rod 4 is mounted on the inner periphery of the rod insertion hole 24b.

[0078] The rod guide 24 is fixed to the head cap 15 together with the seal housing 22 laminated on the left end in Figure 3 of the rod guide 24 by bolts 21. In addition, the fitting portion 24a of the rod guide 24 is in a ring shape and has a groove 24c communicating with the rod side chamber R1 on a part of its outer periphery. The rod guide 24 has a passage 24d communicating the groove 24c and the passage 15d of the head cap 15. Further, the passage 15e of the head cap 15 in the first embodiment is abolished.

[0079] During arrangement, one end side of the passage 23d of the bottom cover 23 communicates with the rod side chamber R1 via the catheter 17, the passage 24d, and the groove 24c, and the other end side communicates with the piston side chamber R2 via the through hole 13a. Therefore, the first passage 7 is formed by the groove 24c, the passage 24d, the passage 15d, inside the catheter 17, the passage 23d, and the through hole 13a, and communicates the rod side chamber R1 and the piston side chamber R2. Moreover, since the first switching valve 8 is provided on the passage 23d, it is provided in the middle of the first passage 7.

[0080] One end side of the passage 23e communicates with the piston side chamber R2 via a portion closer to the piston side chamber R2 than the first switching valve 8 of the passage 23e and the through hole 13a without communicating with the first switching valve 8, and the other end side communicates with the liquid storage tank T through the gap G. Further, the second passage 9 is formed by the through hole 13a, the passage 23e, and a part of the passage 23d, and communicates the piston side chamber R2 and the liquid storage tank T. Moreover, since the second switching valve 10 is provided in the passage 23e, it is provided in the middle of the second passage 9.

[0081] One end side of the passage 23f communicates with the rod-side chamber R1 in a state where the first switching valve 8 of the passage 23d is not connected, via a portion closer to the rod-side chamber R1 side than the first switching valve 8 of the passage 23d, and the other end side communicates with the liquid storage tank T in a state where the second switching valve 10 of the passage 23e is not connected, via a portion closer to the liquid storage tank T side than the second switching valve 10 of the passage 23e. Further, the discharge passage 11 is formed by the groove 24c, the passage 24d, the passage 15d, the inside of the conduit 17, a part of the passage 23d, the passage 23f, and a part of the passage 23e, and communicates the rod-side chamber R1 and the liquid storage tank T. In addition, the control valve 12 is provided on the passage 23f, and thus it is provided in the middle of the discharge passage 11.

[0082] Moreover, a first solenoid 8a, a second solenoid 10a, and a third solenoid 12a are mounted on the bottom cover 23, and a first valve body 8b of the first switching valve 8, a second valve body 10b of the second switching valve 10, and a control valve body 12b of the control valve 12 are provided inside the bottom cover 23.

[0083] Since the cylinder device C1 configured in this way also includes the rectifying passage 5, the suction passage 6, the first passage 7, the second passage 9, the discharge passage 11, the first switching valve 8 provided in the first passage 7, the second switching valve 10 provided in the second passage 9, and the control valve 12 provided in the discharge passage 11, it is the same as the cylinder device C in the first embodiment. By switching the opening and closing of the first switching valve 8 and the second switching valve 10, it can function as a semi-active shock absorber or a passive shock absorber, and furthermore, it can also be in an unloading state.

[0084] Moreover, in the cylinder device C1 of the present embodiment, the first valve body 8b of the first switching valve 8, the second valve body 10b of the second switching valve 10, and the control valve body 12b of the control valve 12 can be built in the bottom cover (cover member) 23 as one component. Therefore, in the cylinder device C1 of the present embodiment, it is not necessary to fix the valve blocks constituting the first switching valve, the valve blocks constituting the second switching valve, and the valve blocks constituting the control valve to the bottom cover (cover member) 23 with bolts respectively. Therefore, according to the cylinder device C1 in the present embodiment, the same as the cylinder device C in the first embodiment, since the valve blocks are not required, the number of bolt fastening parts can be reduced, so that the number of components can be reduced and the device can be miniaturized, and there is no need to worry about hydraulic oil (liquid) leaking to the outside. In addition, according to the cylinder device C in the present embodiment, since it is not necessary to connect the valve blocks to the side of the bottom cover (cover member) 23, for the thickness of the bottom cover (cover member) 23, since the design freedom is improved, it can be limited to the minimum required for this thickness.

[0085] In addition, when the lid member is used as the bottom lid 23, since the first switching valve 8, the second switching valve 10, and the control valve 12, which are heavy objects, are concentrated on the bottom lid 23, there is no need to apply a large load on the rod 4 and the rod guide 24. Therefore, the frictional force between the rod 4 and the bushing 19 provided on the inner periphery of the rod guide 24 can be reduced, which is beneficial to the smooth expansion and contraction of the cylinder device C1.

[0086] In addition, in the cylinder devices C and C1 of the first and second embodiments, when the control valve 12 is a variable relief valve, the pressure in the rod-side chamber R1 can be adjusted. When the cylinder devices C and C1 function as semi-active shock absorbers, the damping force can be easily adjusted, and the damping force of the cylinder devices C and C1 can be controlled without a sensor.

[0087] Next, as in the cylinder device C2 in the third embodiment shown Figure 4 below, a pump P and a motor M can also be provided on the bottom lid 16 so that the cylinder device C2 functions as an actuator.

[0088] The difference between the cylinder device C2 in the third embodiment and the cylinder device C in the first embodiment is that the pump P and the motor M are integrated with the bottom lid 16 of the cylinder device C in the first embodiment.

[0089] In addition to the structure of the bottom lid 16 in the cylinder device C of the first embodiment, the bottom lid 16 in the cylinder device C2 further includes: a pump holding portion 16f that extends laterally; a fitting hole 16g that is located at the left end of Figure 4 and opens on the outer peripheral side from the concave portion 16c and can insert the conduit 18; and a passage 16h that opens from the fitting hole 16g and communicates with the gap G in the concave portion 16c.

[0090] In addition, the head cap 15 further includes: a fitting hole 15f that is located at the left end of Figure 4 and opens at a position axially opposite to the fitting hole 16g of the bottom lid 16; and a passage 15g that opens from the fitting hole 15f and communicates with Figure 4 the left end of. The conduit 18 is fitted in the fitting hole 15f of the head cap 15 and the fitting hole 16g of the bottom lid 16. The conduit 18 is held by the head cap 15 and the bottom lid 16 fixed to the outer cylinder 14. Therefore, even if vibration is input to the cylinder device C2, it will not fall off.

[0091] In addition, the rod guide 2 serving as the lid member includes a passage 2f for communicating the passage 15g to a side closer to the rod-side chamber R1 than the connection point P2 of the passage 2c. In addition, the passage 2f can also be connected to a side closer to the rod-side chamber R1 than the control valve 12 of the passage 2e.

[0092] Upon return, one end side of passage 16h communicates with the liquid storage tank T via the gap G, and the other end side communicates with the rod-side chamber R1 via the conduit 18, passage 15g, passage 2c, and groove 2a3. Moreover, in the cylinder device C2 of the present embodiment, the supply passage S is formed by passage 16h, conduit 18, passage 15g, passage 2c, and groove 2a3, and communicates the rod-side chamber R1 and the liquid storage tank T.

[0093] The pump P is disposed within the pump holding portion 16f of the bottom cover 16. In the present embodiment, it is a gear pump disposed in the middle of passage 16h. Further, the motor M is fastened to the cylinder-side end of the pump holding portion 16f of the bottom cover 16 in parallel with the cylinder 1 by bolts (not shown). The output shaft (not shown) in the motor M is connected to the drive shaft of the pump P, and the pump P can be driven by the motor M. When the pump P is driven by the motor M, hydraulic oil is sucked from the liquid storage tank T and supplied into the rod-side chamber R1. Additionally, the pump P can also be a pump other than a gear pump. Furthermore, the motor M can also be provided with a speed reducer. In this case, the output shaft of the speed reducer is simply connected to the pump P.

[0094] Moreover, in the middle of passage 16h, on the side closer to the rod-side chamber R1 than the pump P, a check valve 25 is provided that only allows hydraulic oil to flow from the pump P to the rod-side chamber R1, which is used to prevent the hydraulic oil from flowing back from the rod-side chamber R1 to the pump P side.

[0095] In the cylinder device C2 configured in this way, while driving the pump P with the motor M, when the first switching valve 8 is in the connected position and the second switching valve 10 is in the cut-off position, the rod-side chamber R1 and the piston-side chamber R2 are put into a communicating state through the first passage 7, and hydraulic oil is supplied to both of them. Through the supply of hydraulic oil, the total volume of the rod-side chamber R1 and the piston-side chamber R2 increases, and the rod 4 is pushed out to the Figure 4 left in the [cylinder 1], so that the cylinder device C2 exhibits an extending action. When the pressure in the rod-side chamber R1 and the piston-side chamber R2 exceeds the opening pressure of the control valve 12, the control valve 12 opens, and the hydraulic oil is discharged to the liquid storage tank T via the discharge passage 11. 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 control valve 12, and this opening pressure is determined by the amount of current applied to the third solenoid 12a. Therefore, the cylinder device C2 exerts a thrust in the extending direction, and this thrust is equal to the value obtained by multiplying the difference in the pressure-receiving areas on the piston-side chamber R2 side and the rod-side chamber R1 side in the piston 3 by the opening pressure of the control valve 12. In addition, the thrust generated by the cylinder device C2 is achieved by adjusting the amount of current applied to the third solenoid 12a.

[0096] On the other hand, in the cylinder device C2, while the pump P is driven by the motor M, when the first switching valve 8 is in the cut-off position and the second switching valve 10 is in the communication position, hydraulic oil is only supplied to the rod-side chamber R1 and the rod-side chamber R1 expands. Conversely, the hydraulic oil is discharged from the contracted piston-side chamber R2 into the liquid storage tank T through the second passage 9 in the communicating state. Then, the piston 3 is pushed Figure 4 to the right in Figure 4 , and the cylinder device C2 exhibits a contraction action. In this case, the pressure in the piston-side chamber R2 is the liquid storage tank pressure and is constant, while the pressure in the rod-side chamber R1 is controlled to be equal to the valve opening pressure of the control valve 12. Therefore, the cylinder device C2 exerts a thrust in the contraction direction, and this thrust is equal to the value obtained by multiplying the pressure receiving area on the rod-side chamber R1 side of the piston 3 by the valve opening pressure of the control valve 12. In addition, the thrust generated by the cylinder device C2 is achieved by adjusting the amount of current applied to the third solenoid 12a.

[0097] In addition, when the pump P stops, similar to the cylinder device C, the cylinder device C2 includes a rectifying passage 5, a suction passage 6, a first passage 7, a second passage 9, a discharge passage 11, a first switching valve 8 provided in the first passage 7, a second switching valve 10 provided in the second passage 9, and a control valve 12 provided on the discharge passage 11. Therefore, similar to the cylinder device C in the first embodiment, by switching the opening and closing of the first switching valve 8 and the second switching valve 10, it can function as a semi-active shock absorber or a passive shock absorber, and furthermore, it can also be in an unloaded state. In addition, when the cylinder device C2 is in the unloaded state, even if the pump P is driven, the cylinder device C2 will not extend or contract, and no damping force will be generated relative to vibration due to external forces.

[0098] In this way, in addition to the structure of the cylinder device C in the aforementioned first embodiment, the cylinder device C2 in the third embodiment further includes a supply passage S for communicating the liquid storage tank T and the rod-side chamber R1, a pump P provided in the middle of the supply passage S for sucking hydraulic oil (liquid) from the liquid storage tank T and supplying the hydraulic oil (liquid) to the rod-side chamber R1, and a motor M for driving the pump P. The cover member is the rod guide 2, which closes one end of the cylinder 1 and allows the rod 4 to be inserted into the inner peripheral side, guides the axial movement of the rod 4, and the pump P and the motor M are mounted on the bottom cover 16. According to the cylinder device C2 configured in this way, since the first switching valve 8, the second switching valve 10, and the control valve 12, which are heavy objects, and the pump P and the motor M, which are also heavy objects, can be arranged in a well-balanced manner on the rod guide 2 and the bottom cover 16 in the cylinder 1, the weight balance is good, and it is also possible to prevent a large load from being applied only to one of the vibration isolation rubbers V1 and V2 mounted on the brackets 4a and 16a.

[0099] In addition, it can also be asFigure 5 As in the cylinder device C3 in the fourth embodiment shown, a pump P and a motor M are provided on the rod guide 24 so that the cylinder device C3 functions as an actuator.

[0100] The difference between the cylinder device C3 in the fourth embodiment and the cylinder device C1 in the second embodiment is that the pump P and the motor M are integrated with the rod guide 24 of the cylinder device C1 in the second embodiment.

[0101] In addition to the structure of the rod guide 24 in the cylinder device C1 of the second embodiment, the rod guide 24 in the cylinder device C3 further includes a pump holding portion 24e extending laterally and a Figure 5 passage 24f that opens at the right end of the [] and communicates with the groove 24c.

[0102] In addition, the head cap 15 has a fitting hole 15f that opens at the right end of the [] facing the liquid storage tank T and a passage 15g that opens from the fitting hole 15f and communicates with the Figure 5 left end of the []. Figure 5 In addition to the structure of the cylinder device C1 in the second embodiment, the bottom cover 23 further includes: a fitting hole 23g that is located at the left end of the [] facing the liquid storage tank T and opens at a position axially opposite to the fitting hole 15f provided on the head cap 15; and a passage 23h that communicates the fitting hole 23g and the gap G.

[0103] A conduit 18 is fitted into the fitting hole 15f of the head cap 15 and the fitting hole 23g of the bottom cover 23. The conduit 18 is held by the head cap 15 and the bottom cover 16 fixed to the outer cylinder 14. Therefore, even if vibration is input to the cylinder device C3, it will not fall off. Figure 5

[0104]

[0105] ​​One end side of the passage 24f of the rod guide 24 communicates with the rod-side chamber R1 via the groove 24c, and the other end side communicates with the liquid storage tank T via the passage 15g, the conduit 18, the passage 23h, and the gap G. Therefore, the supply passage S is formed by the groove 24c, the passage 24f, the passage 15g, the conduit 18, and the passage 23h, and communicates the rod-side chamber R1 and the liquid storage tank T. Moreover, the pump P is disposed within the pump holding portion 24e of the rod guide 24, and in the present embodiment, it is a gear pump disposed in the middle of the passage 24f. In addition, the motor M is fastened to the cylinder-side end of the pump holding portion 24e of the rod guide 24 in parallel with the cylinder 1 by bolts (not shown), and it is considered that the motor M does not interfere with the axial movement of the rod 4 relative to the cylinder 1. An output shaft (not shown) in the motor M is connected to the drive shaft of the pump P, and the pump P can be driven by the motor M. When the pump P is driven by the motor M, hydraulic oil is sucked from the liquid storage tank T and supplied into the rod-side chamber R1. Additionally, the pump P can also be a pump other than a gear pump. Further, the motor M can also be provided with a speed reducer, and in this case, the output shaft of the speed reducer may be connected to the pump P.

[0106] In addition, in the middle of the passage 24f, on the side closer to the rod-side chamber R1 than the pump P, a check valve 26 for only allowing hydraulic oil to flow from the pump P to the rod-side chamber R1 is provided to prevent the hydraulic oil from flowing back from the rod-side chamber R1 to the pump P side.

[0107] In the cylinder device C3 configured in this way, while driving the pump P with the motor M, when the first switching valve 8 is in the connected position and the second switching valve 10 is in the cut-off position, the rod-side chamber R1 and the piston-side chamber R2 are put into a communicating state through the first passage 7, and hydraulic oil is supplied to both of them. Through the supply of the hydraulic oil, the total volume of the rod-side chamber R1 and the piston-side chamber R2 increases, and the rod 4 is pushed out to the left in the Figure 5 so that the cylinder device C3 exhibits an extending action. When the pressure in the rod-side chamber R1 and the piston-side chamber R2 exceeds the opening pressure of the control valve 12, the control valve 12 opens, and the hydraulic oil is discharged to the liquid storage tank T via the discharge passage 11. 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 control valve 12, and this opening pressure is determined by the amount of electric current applied to the third solenoid 12a. Therefore, the cylinder device C3 exerts a thrust in the extending direction, and this thrust is equal to the value obtained by multiplying the pressure-receiving area difference between the piston-side chamber R2 side and the rod-side chamber R1 side in the piston 3 by the opening pressure of the control valve 12. In addition, the thrust generated by the cylinder device C3 is achieved by adjusting the amount of electric current applied to the third solenoid 12a.

[0108] On the other hand, in the cylinder device C3, while driving the pump P with the motor M, when the first switching valve 8 is in the cut-off position and the second switching valve 10 is in the communicating position, the hydraulic oil is supplied only to the rod-side chamber R1 and the rod-side chamber R1 expands. Conversely, the hydraulic oil is discharged from the contracted piston-side chamber R2 through the second passage 9 in the communicating state to the liquid storage tank T. Then, the piston 3 is pushed Figure 5 to the right in Figure 5 , and the cylinder device C2 exhibits a contraction action. In this case, the pressure in the piston-side chamber R2 is the liquid storage tank pressure and is constant, while the pressure in the rod-side chamber R1 is controlled to be equal to the opening pressure of the control valve 12. Therefore, the cylinder device C3 exerts a thrust in the contraction direction, and this thrust is equal to the value obtained by multiplying the pressure receiving area on the rod-side chamber R1 side of the piston 3 by the opening pressure of the control valve 12. In addition, the thrust generated by the cylinder device C2 is achieved by adjusting the amount of current applied to the third solenoid 12a.

[0109] In addition, when the pump P stops, similar to the cylinder device C1, the cylinder device C3 includes a rectifying passage 5, a suction passage 6, a first passage 7, a second passage 9, a discharge passage 11, a first switching valve 8 provided in the first passage 7, a second switching valve 10 provided in the second passage 9, and a control valve 12 provided on the discharge passage 11. Therefore, by switching the opening and closing of the first switching valve 8 and the second switching valve 10, it can function as a semi-active shock absorber or a passive shock absorber, and furthermore, it can also be in an unloaded state. In addition, when the cylinder device C3 is in the unloaded state, even if the pump P is driven, it will not extend or contract, and no damping force will be generated with respect to vibration due to external force.

[0110] In this way, in addition to the structure of the cylinder device C1 in the aforementioned second embodiment, the cylinder device C3 in the fourth embodiment further includes a supply passage S for communicating the liquid storage tank T and the rod-side chamber R1, a pump P provided in the middle of the supply passage S for sucking hydraulic oil (liquid) from the liquid storage tank T and supplying the hydraulic oil (liquid) to the rod-side chamber R1, and a motor M for driving the pump P. The cover member is a bottom cover 23, which closes one end of the cylinder 1 and allows the rod 4 to be inserted through to the inner peripheral side, and the pump P and the motor M are mounted on a rod guide 24 for guiding the axial movement of the rod 4. According to the cylinder device C3 configured in this way, since the first switching valve 8, the second switching valve 10, and the control valve 12, which are heavy objects, and the pump P and the motor M, which are also heavy objects, can be arranged well-balanced on the rod guide 24 and the bottom cover 23 in the cylinder 1, the weight balance is good, and it is also possible to prevent a large load from being applied only to one of the vibration isolation rubbers V1 and V2 mounted on the brackets 4a and 23c.

[0111] In addition, in the cylinder devices C2 and C3 of the third and fourth embodiments, when the control valve 12 is a variable relief valve, the pressure in the rod-side chamber R1 can be adjusted, and when the cylinder devices C2 and C3 function as actuators, the thrust can be easily adjusted. Further, in addition to being able to control the thrust of the cylinder devices C2 and C3 without sensors, the motor M only needs to drive the pump P at a constant rotational speed, and there is no need to highly control the motor M in order to adjust the discharge flow rate of the pump P. Therefore, the cylinder devices C2 and C3 are inexpensive, and a robust system can be constructed both in terms of hardware and software.

[0112] In each embodiment, in addition to the variable relief valve, the control valve 12 can also adopt various other valves. For example, as Figure 6 shown, when the rod guide 2 or the bottom cover 23 is used as the cover member, it can include: a damping passage 30 and a pressure relief passage 31 arranged in parallel in the discharge passage 11 of the cover member, a control valve body 32 provided on the damping passage 30 for switching the damping passage 30, a switching valve body 33 for switching the pressure relief passage 31, a first spring 34 for applying a force to the control valve body 32 in the direction of closing the damping passage 30, a second spring 35 for applying a force to the switching valve body 33 in the same direction as the first spring 34 and in the direction of opening the pressure relief passage 31, and a third solenoid 36 for resisting the acting forces of the first spring 34 and the second spring 35 and applying a thrust to the control valve body 32 via the switching valve body 33, and is constituted thereby.

[0113] The third solenoid 36 is installed outside the rod guide 2 or the bottom cover 23 serving as the cover member, and the damping passage 30, the pressure relief passage 31, the control valve body 32, the switching valve body 33, the first spring 34, and the second spring 35 are provided inside the rod guide 2 or the bottom cover 23 serving as the cover member.

[0114] Regarding Figure 6 each part of the control valve 12 shown, the damping passage 30 and the pressure relief passage 31 are arranged in parallel in the middle of the discharge passage 11. The control valve body 32 provided in the damping passage 30 is urged in the valve-opening direction by the pressure in the rod-side chamber R1 through the pilot passage 37, and is urged in the valve-closing direction by the first spring 34.

[0115] The switching valve body 33 provided on the pressure relief passage 31 is biased in the valve opening direction by a second spring 35 having the same biasing direction as the first spring 34. The third solenoid 36 applies a thrust in the valve closing direction to the switching valve body 33. The switching valve body 33 applies a preset resistance to the flow of hydraulic oil when the valve is opened. The switching valve body 33 and the control valve body 32 are arranged adjacent to each other in a separated state, and in a state where the third solenoid 36 is not energized, the switching valve body 33 adopts a position where the pressure relief passage 31 is communicated through the second spring 35, while the control valve body 32 is biased by the first spring 34 and the valve opening pressure is maximized. When the third solenoid 36 is energized and applies a thrust capable of compressing the second spring 35 to close the valve to the switching valve body 33, the switching valve body 33 switches to a cut-off position for cutting off the pressure relief passage 31 and abuts against the adjacent control valve body 32, and applies the thrust of the third solenoid 36 to the control valve body 32 in the valve opening direction.

[0116] Therefore, when a current equal to or greater than the amount of current (necessary current amount) required to apply a thrust required to switch the switching valve body 33 to the cut-off position is applied to the third solenoid 36, the thrust of the third solenoid 36 can be applied to the control valve body 32 via the switching valve body 33. Moreover, when a current in a range equal to or greater than the necessary current amount is applied to the third solenoid 36 and the current amount is adjusted, the thrust acting on the control valve body 32 is adjusted, and the valve opening pressure of the control valve body 32 can be adjusted.

[0117] Therefore, when the control valve 12 configured in this way is used, the damping force or thrust of the cylinder devices C, C1, C2, C3 can be adjusted by adjusting the current amount of the third solenoid 36. In addition, when the third solenoid 36 is not energized or cannot be energized, the switching valve body 33 opens the pressure relief passage 31 and applies a predetermined resistance to the flow of hydraulic oil. Therefore, when the cylinder devices C, C1, C2, C3 function as passive shock absorbers or fail, a preset damping force can be generated by the switching valve body 33. Further, when the third solenoid 36 is not energized or cannot be energized, the control valve body 32 maximizes the valve opening pressure, but prevents a situation where the valve is opened and the pressure in the cylinder 1 becomes excessive when the pressure in the cylinder 1 increases.

[0118] Thus, when the rod guide 2 or the bottom cover 23 is used as the cover member, the control valve 12 includes a damping passage 30 and a pressure relief passage 31 arranged in parallel in the discharge passage 11 of the cover member, a control valve body 32 provided on the damping passage 30 for opening and closing the damping passage 30, a switching valve body 33 for opening and closing the pressure relief passage 31, a first spring 34 for applying a force to the control valve body 32 in a direction to close the damping passage 30, a second spring 35 for applying a force to the switching valve body 33 in the same direction as the first spring 34 and in a direction to open the pressure relief passage 31, and a third solenoid 36 for resisting the acting forces of the first spring 34 and the second spring 35 and applying a thrust to the control valve body 32 via the switching valve body 33. When constituted in this way, not only can the damping force or thrust of the cylinder devices C, C1, C2, and C3 be adjusted, but also the damping force during a failure can be set to a predetermined magnitude. In addition, for the setting of the damping force during a failure, in addition to being set by the flow path resistance at the communication position of the switching valve body 33, a damping valve such as an overflow valve or a throttle valve for applying resistance can be provided on the pressure relief passage 31 instead of the switching valve body 33 during the setting.

[0119] In addition, the uses of the cylinder devices C, C1, C2, and C3 are not only for suppressing the vibrations of railway vehicles, but also for various uses such as buildings, suppressing mechanical vibrations, and suppressing vehicle vibrations.

[0120] The preferred embodiments of the present invention have been described in detail above, but modifications, deformations, and changes can be made as long as they do not depart from the scope of the claims.

Claims

1. A cylinder device, characterized in that, It includes: A cylinder; A piston that can slide freely into the cylinder; A rod that is inserted into the cylinder and connected to the piston; A ring-shaped rod guide that closes one end of the cylinder and allows the rod to pass through to the inner circumferential side to guide the axial movement of the rod; A bottom cover that closes the other end of the cylinder; A rod-side chamber and a piston-side chamber that are divided in the cylinder by the piston; A liquid storage tank that stores liquid; A rectifying channel that only allows liquid to flow from the piston-side chamber to the rod-side chamber; An intake channel that only allows liquid to flow from the liquid storage tank to the piston-side chamber; A first channel that connects the rod-side chamber and the piston-side chamber; A first switching valve that is provided in the middle of the first channel; A second channel that connects the piston-side chamber and the liquid storage tank; A second switching valve that is provided in the middle of the second channel; A discharge channel that connects the rod-side chamber to the liquid storage tank; And a control valve that is provided in the middle of the discharge channel, When the rod guide is used as a cover member, the first switching valve has a first valve body that is provided in the cover member and switches the first channel, and a first solenoid that is mounted on the cover member and drives the first valve body, The second switching valve has a second valve body that is provided in the cover member and switches the second channel, and a second solenoid that is mounted on the cover member and drives the second valve body, The control valve has a control valve body that is provided in the cover member and switches the discharge channel, and a third solenoid that is provided in the cover member and applies a thrust to the control valve body.

2. The cylinder device according to claim 1, characterized in that It includes: A supply channel that connects the liquid storage tank and the rod-side chamber; A pump that is provided in the middle of the supply channel and sucks liquid from the liquid storage tank and supplies the liquid to the rod-side chamber; And a motor that is used to drive the pump, The pump and the motor are mounted on the bottom cover.

Images