JP6695718B2 - Cylinder device - Google Patents

Description

  The present invention relates to a cylinder device.

  For example, in a cylinder device attached to a structure as a damping device that damps vibrations of a structure, or in a cylinder device that is used as a damping device that damps vertical movements of a running wheel of a railroad vehicle or the like, a cylinder device is enclosed in a cylinder. Damping force is generated by the flow path resistance when the working fluid (working oil) passes through the minute flow path of the damping mechanism (throttle) provided in the piston as the piston reciprocates (for example, patents Reference 1).

  In such a cylinder device, the sliding stroke (stroke) of the piston in the cylinder is determined by design, and damping is performed with respect to the piston speed within that range.

  Also, in the cylinder device, when the piston moves to a position exceeding the predetermined sliding stroke, a clearance of a predetermined size is provided so that the piston does not collide with the inner wall of the cylinder end portion in the piston moving direction immediately, and the cylinder end A stopper is provided on the inner wall of the part. However, when an unexpectedly large acceleration is input to the cylinder device, the piston moves to a position beyond the sliding stroke and collides with the stopper.

  In such a situation, since the damping force against the input acceleration (piston speed) cannot be obtained sufficiently, the piston is communicated from the inside of the cylinder to the reservoir chamber formed in parallel to the outside of the cylinder immediately before it collides with the stopper. By shutting off the orifice, the damping force is increased and the shock is suppressed.

  However, if the orifice that connects the cylinder and the reservoir chamber is cut off immediately before the piston collides with the stopper as described above, the working fluid that accompanies the movement of the piston passes through only the minute flow path of the damping mechanism provided in the piston. I will let you. Therefore, if the damping force is increased when the piston reaches the position just before the stroke end of the sliding stroke, an excessive force acts on the structure connected to both ends of the cylinder device or each support part of the vehicle. Therefore, there is a possibility that the supporting portion may be deformed or damaged.

  Therefore, in the conventional cylinder device, for example, as described in Patent Document 1, a spiral groove around the axis around the piston movement direction is formed in the cylinder inner peripheral wall inside the stroke end of the piston. As a result, immediately before the piston collides with the stopper, both end faces of the piston straddle the spiral groove, and the working fluid in the cylinder chamber (first chamber) pressurized by the piston passes through the spiral groove and becomes non-conductive. The damping force is reduced by flowing into the cylinder chamber (second chamber) on the pressurizing side. As a result, an excessive force does not act on the support mechanism to which the end portion of the piston rod of the cylinder device and the end portion of the cylinder body are connected, and damage to the support mechanism can be suppressed.

Japanese Patent Laid-Open No. 2000-18308

  However, in the above-mentioned conventional cylinder device, it is difficult to accurately machine the spiral groove on the inner peripheral wall of the cylinder, and the outer periphery of the piston comes into sliding contact with the corner of the spiral groove when reciprocating in the cylinder. .. Therefore, conventionally, there is a problem that the outer peripheral surface of the piston is scratched by rubbing against the edge of the spiral groove, or the ring-shaped seal member provided on the outer peripheral surface of the piston is easily worn and the durability is reduced. It was

  In view of the above circumstances, the present invention has an object to provide a cylinder device that solves the above problems.

  In order to solve the above problems, the present invention has the following means.

The present invention relates to a cylinder in which a working fluid is sealed, a piston that defines the inside of the cylinder into a first chamber and a second chamber, and slides in the cylinder, a rod connected to the piston, and the piston. provided, accompanied by the first chamber and the second chamber, the communicating path that communicates, to the passage of opened and working fluid by a pressure differential between the first chamber and the second chamber with the movement of the piston A valve having a damping valve that generates a damping force and a valve portion that is arranged at a position radially separated from the central axis of the piston and that increases the passage area of the communication passage when the piston approaches the stroke end. and wherein the kite comprising a mechanism.

  ADVANTAGE OF THE INVENTION According to this invention, damage of a piston and abrasion of the seal member provided in the outer periphery of a piston can be suppressed and durability can be improved.

It is an AA sectional view showing an internal structure of a cylinder device in a 1st embodiment of the present invention. It is a BB sectional view showing an internal structure of a cylinder device in a 1st embodiment of the present invention. It is sectional drawing which expands and shows the damping force switching mechanism in the 1st Embodiment of this invention. It is sectional drawing which expands and shows the operation | movement in the stroke end of the damping force switching mechanism in the 1st Embodiment of this invention. It is the figure which looked at the one side end surface of the piston in the 1st Embodiment of this invention from the axial direction. 3 is a graph showing a relationship between a piston stroke and a damping force of the cylinder device according to the first embodiment of the present invention. It is sectional drawing which shows the internal structure of the cylinder apparatus in the 2nd Embodiment of this invention. It is sectional drawing which shows the internal structure of the cylinder apparatus in the 3rd Embodiment of this invention. It is sectional drawing which shows the internal structure of the cylinder apparatus in the 4th Embodiment of this invention. It is sectional drawing which expands and shows the damping force switching mechanism in the 4th Embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[Structure of cylinder device]
FIG. 1 is a sectional view showing the internal structure of a cylinder device according to the first embodiment of the present invention. Note that FIG. 1 shows an irregular cross-sectional view taken along the line AA shown in FIG. As shown in FIGS. 1 and 5, the cylinder device 10 is a hydraulic shock absorber in which working oil (working fluid) F is enclosed in the cylinder. The cylinder device 10 also includes a cylinder 20 in which hydraulic oil is sealed, a piston 30 that slides inside the cylinder 20, and a piston rod 40 that is connected to the piston 30.

  The cylinder 20 has a cylinder chamber 22 inside, and the cylinder chamber 22 is defined by a piston 30 into a first chamber 24 and a second chamber 26. The first chamber 24 and the second chamber 26 are filled with hydraulic oil. The first and second lid members 25 and 27 are fixed to both ends of the cylinder body 21 of the cylinder 20, and the first and second guide members are provided inside the first and second lid members 25 and 27. Members 28, 29 are arranged. Further, a cylindrical hollow rod 151 formed so as to cover an accumulator 160 described later is fixed to the second lid member 27. In the first embodiment, the end portion of the piston rod 40 extending in the X1 direction and the end portion of the hollow rod 151 extending in the X2 direction are connected to, for example, the support portion of the structure.

  The piston 30 has a temperature compensation valve mechanism 90, first and second relief valves 100 and 110, and first and second pressure regulating valves 120 and 130 in addition to the damping force switching mechanisms 50 and 60.

  In the first embodiment, the damping force generating mechanism includes first and second relief valves 100 and 110, and first and second pressure regulating valves 120 and 130. It should be noted that each relief valve and each pressure regulating valve are set to open according to the pressure change in the first chamber 24 and the second chamber 26, and the number of relief valves and pressure regulating valves installed is required. It is desirable to arrange them so that damping characteristics can be obtained.

  FIG. 1 shows a first relief valve 100 that operates when the temperature compensation valve mechanism 90 and the piston 30 slide in the X1 direction. As shown in FIG. 5, the piston 30 slides in the X1 direction. The first pressure regulating valve 120, which operates when moving, and the second relief valve 110 and the second pressure regulating valve 130, which operate when the piston 30 slides in the X2 direction, are arranged at positions displaced in the circumferential direction. Note that the structures of the second relief valve 110 and the first and second pressure regulating valves 120 and 130 are the same as those of the first relief valve 100, so description thereof will be omitted.

  The piston rod 40 has a first piston rod 42 provided on one side (X1 direction side) of the piston 30 and a second piston rod 44 provided on the other side (X2 direction side) of the piston 30. The first piston rod 42 has a large diameter portion 42a extending to one side of the piston 30 (X1 direction side) and a small diameter portion 42b penetrating the central hole 32 of the piston 30. The second piston rod 44 is formed in a hollow cylindrical shape, and has an inner diameter portion 44 a through which the small diameter portion 42 b of the first piston rod 42 is inserted and an outer diameter that is the same as the outer diameter of the first piston rod 42. And a portion 44b.

  As described above, since the outer diameters of the piston rod 40 on one side and the other side of the piston 30 are the same, when the piston 30 reciprocates in the X1 and X2 directions, the first chamber accompanying the movement of the piston rod 40 There is no difference between the inflow amount and the outflow amount of the hydraulic oil in the 24 and the second chamber 26. Further, the piston rod 40 is slidably supported in the X1 and X2 directions by the central holes 28a and 29a of the first and second guide members 28 and 29 provided in the axial direction of the cylinder 20. Further, first and second stopper portions 28b and 29b for restricting strokes of the piston 30 in the X1 and X2 directions within a predetermined sliding range are provided at inner ends of the first and second guide members 28 and 29 in the axial direction. It projects toward the cylinder chamber.

  Further, the piston 30 has a temperature compensation path 140 and a relief path 150. The temperature compensation path 140 has a communication hole 146 penetrating the small diameter portion 42b of the first piston rod 42, and the communication hole 146 communicates with the accumulator 160.

  In the temperature compensating path 140, a first valve 142 provided with an orifice 142a which is opened and always communicates with the flow from the accumulator 160 to the first chamber 24, and from the accumulator 160 to the second chamber 26. And a second valve 144 which is provided with an orifice 144a which is open to the above flow and is always in communication with the second valve 144. Then, when the oil liquid in the first and second chambers 24, 26 thermally expands, the working fluid is recovered via the orifices 142a, 144a, and the contraction amount of the working fluid due to the temperature decrease or some cause Thus, the temperature compensating valve mechanism 90 for replenishing the oil liquid when the first and second chambers 24, 26 become negative pressure is configured. In addition, the accumulator 160 absorbs the working fluid in the storage chamber 162 in which the working fluid is stored and the thermal expansion amount due to the temperature increase by the operation of the accumulator piston 164, and supplies the working fluid in the contraction amount due to the temperature decrease. It is a thing.

  In addition, when the pressure in the first chamber 24 and the second chamber 26 rises when the piston 30 reciprocates, the first and second valves 142 and 144 maintain the valve open state and are pressurized by the piston 30. The stored working fluid is prevented from being supplied to the accumulator 160.

  The relief path 150 is provided with a first relief valve 100 that opens due to a pressure difference between the first chamber 24 and the second chamber 26 due to the movement of the piston 30 to generate a damping force due to the passage of the working fluid. There is. Further, the first relief valve 100 has a valve body 100a that opens or closes according to the pressure change of the working fluid pressurized in the first chamber 24 due to the operation of the piston 30. That is, when the pressure in the first chamber 24 becomes higher than the pressure in the second chamber 26 by a predetermined pressure or more, the valve body 100a opens, and the working fluid in the first chamber 24 passes through the first relief valve 100. Move to the second chamber 26. At that time, in the first relief valve 100, a damping force due to viscous resistance is generated during the passage of the working fluid, and it functions as a damping valve that converts the input vibration energy into heat and attenuates it.

  The second relief valve 110 and the first and second pressure regulating valves 120 and 130 are provided as damping valves like the first relief valve 100, and are appropriately opened and damped by the pressure difference caused by the operation of the piston 30. It is a damping valve that generates force. The first relief valve 100 and the first pressure regulating valve 120 are opened to generate a damping force when the piston 30 moves in the X1 direction, and the second relief valve 110 and the second pressure regulating valve 130 are connected to the piston 30. Is provided so as to generate a damping force by opening the valve when moving in the X2 direction.

  Further, the spring constants of springs for urging the valve bodies are set to different values so that the opening timings of the first and second relief valves 100 and 110 and the first and second pressure regulating valves 120 and 130 are deviated. There is. It is also possible to set the first and second relief valves 100 and 110 and the first and second pressure regulating valves 120 and 130 to open at substantially the same time.

  FIG. 2 is a sectional view showing the internal structure of the cylinder device according to the first embodiment of the present invention. Note that FIG. 2 shows a sectional view taken along the line BB shown in FIG.

  The cylinder 20 of the first embodiment is a cylindrical assembly in which a plurality of parts are combined, but the shape of each part and the number of divisions are not limited to this, and therefore the description of each part is omitted. ..

  The piston 30 has first and second damping force switching mechanisms (valve mechanisms) 50 and 60 that switch to reduce the damping force when the piston 30 comes into contact with the first and second stopper portions 28b and 29b.

  The first damping force switching mechanism 50 is provided in the first communication passage 34 formed inside the piston 30. The second damping force switching mechanism 60 is provided in the second communication passage 36 formed inside the piston 30. Each of the communication passages 34 and 36 is formed inside the piston 30 so as to intersect with the first and second damping force switching mechanisms 50 and 60, and communicates the first chamber 24 and the second chamber 26 through separate paths. ing. Further, first and second check valves 70 and 80, which will be described later, are provided in the respective communication passages 34 and 36.

[Structure of damping force switching mechanism]
FIG. 3 is an enlarged sectional view showing a damping force switching mechanism according to the first embodiment of the present invention. As shown in FIG. 3, the first damping force switching mechanism 50 has a passage area in the first communication passage 34 when the X1 direction side end surface of the piston 30 reaches a predetermined position immediately before contacting the first stopper portion 28b. Is largely changed, and has a first valve portion 52, a first shaft member 54, and a first spring member (biasing member) 56. The first valve portion 52 and the first shaft member 54 are biased by the first spring member in a direction (X1 direction) protruding from the end surface of the piston 30.

  The first shaft member 54 sets the timing of the damping force reduction with respect to the piston position to a predetermined position by the length of the first shaft member 54 that projects in the axial direction from the end surface 30a on the X1 side. The first shaft member 54 has a small diameter small passage 54 a that penetrates the inside in the axial direction, and the base end portion is coupled to the first valve portion 52. Therefore, since the first valve portion 52 and the first shaft member 54 are movable in the axial direction, when the end portion of the first shaft member 54 comes into contact with the end portion of the first stopper portion 28b, the piston 30 moves relative to each other. The first valve portion 52 opens due to the displacement.

  In the first embodiment, the first valve portion 52 is provided with a spool 52a having a smaller diameter than both end portions and a seal portion 52b having a larger diameter than the spool 52a. Further, the first valve portion 52 is biased in the X1 direction by the first spring member 56. Therefore, the spool 52a of the first valve portion 52 is at a position separated from the first communication passage 34, and the large-diameter seal portion 52b closes the first communication passage 34.

  Further, the first valve portion 52 has a small flow passage 52c having a minute passage area penetrating the axis. The small flow path 52c communicates with the small flow path 54a of the first shaft member 54 described above. Therefore, even when the first valve portion 52 closes the first communication passage 34, the working fluid pressurized in the first chamber 24 due to the movement of the piston 30 passes through the small flow paths 54a and 52c. The pressure inside the insertion hole is made equal to the pressure inside the first chamber 24. Therefore, the first valve portion 52 is provided so as not to open due to the pressure of the working fluid in the first chamber 24.

  Further, the first shaft member 54 projects axially by a predetermined length from the end surface 30a of the piston 30 on the X1 direction side by the spring force of the first spring member 56. The protruding length of the first shaft member 54 is appropriately set according to the pressure reduction start position with respect to the piston stroke end. That is, when the piston 30 approaches the piston stroke end, it is determined by the position of the timing for reducing the damping force with respect to the piston stroke.

[Operation of damping force switching mechanism]
FIG. 4 is an enlarged sectional view showing the operation at the stroke end of the damping force switching mechanism according to the first embodiment of the present invention. As shown in FIG. 4, when the piston 30 moves in the X1 direction, the tip portion of the first shaft member 54 approaches the end portion of the first stopper portion 28b of the first guide member 28. In the operation process of the piston 30, the pressure in the first chamber 24 increases and a pressure difference is generated between the first chamber 24 and the second chamber 26. Therefore, when the piston 30 reciprocates in the cylinder 20, the first and second relief valves 100 and 110 and the first and second pressure regulating valves 120 and 130 (see FIG. 1) to be described later are opened and closed. A damping force is generated. Therefore, when vibration energy is input to the cylinder device 10, the first and second relief valves 100 and 110 and the first and second pressure regulating valves 120 and 130 (see FIG. 1) corresponding to the moving direction of the piston 30 are input. A damping force is generated by the viscous resistance when the working fluid passes through either of them, and the input vibration energy can be attenuated.

  Further, when the piston 30 approaches the stroke end in the cylinder 20, the tip portion of the first shaft member 54 contacts the end portion of the first stopper portion 28b of the first guide member 28. This allows the piston 30 to move in the X1 direction and the first shaft member 54 to relatively move the first valve portion 52 in the X2 direction. When the piston 30 further moves in the X1 direction and reaches the position immediately before contacting the first guide member 28, the first shaft member 54 and the first valve portion 52 are pressed in the X2 direction which is the opposite direction to the piston moving direction. To be done. As a result, the spool 52a of the first valve portion 52 reaches the damping force switching position that intersects with the first communication passage 34.

  Then, since the flow rate of the working fluid flowing through the first communication passage 34 is increased and the first check valve 70 is opened by the pressure of the working fluid, the pressurized working fluid in the first chamber 24 is It passes through the first communication passage 34 via the first communication passage 34 and flows out to the second chamber 26. As a result, just before the piston 30 contacts the first stopper portion 28b, part of the working fluid pressurized in the first chamber 24 due to the movement of the piston 30 moves to the second chamber 26. As a result, the pressure in the first chamber 24 is reduced, so that it is possible to suppress an excessive force from acting on the support portion such as the structure to which the cylinder device 10 is attached.

  The second damping force switching mechanism 60 reduces the passage area of the second communication passage 36 when the X2 direction side end surface 30b of the piston 30 reaches a predetermined position immediately before contacting the second stopper portion 29b of the second guide member 29. It is configured to be large, and includes a second valve portion 62, a second shaft member 64, and a second spring member 66. That is, the second damping force switching mechanism 60 has the same configuration as the first damping force switching mechanism 50, and is provided in a direction 180 degrees reversed from the axial first axial damping force switching mechanism 50. The operations of the second valve portion 62 and the second shaft member 64 when the piston 30 moves in the X2 direction are the same as in the case of the first damping force switching mechanism 50 described above.

[Change pattern of damping force]
Here, a change in damping force in the cylinder device 10 configured as described above will be described. FIG. 6 is a graph showing the relationship between the piston stroke and the damping force of the cylinder device according to the first embodiment of the present invention.

  A graph G shown in FIG. 6 shows the relationship between the piston stroke indicated by the horizontal axis in the orthogonal coordinate system and the damping force indicated by the vertical axis according to the piston stroke. In addition, the displacement is the case of operating with a sine wave. In the first quadrant and the third quadrant, steep slopes α and β showing a decrease in damping force near the stroke end of the piston 30 appear. In the other quadrants 4 and 4, the damping force near the stroke end increases and changes in a circular pattern with substantially the same radius.

  For example, when the first damping force switching mechanism 50 shown in FIGS. 2 to 4 is not provided, the damping force near the stroke end of the piston 30 has a circular pattern in the first quadrant and the third quadrant, as shown by the broken line. In this case, it can be seen that the damping force in the first and second relief valves 100 and 110 as the damping valve and the first and second pressure regulating valves 120 and 130 is generated until the piston 30 reaches the stroke end. Further, the change in the damping force due to the circular pattern maintains a relatively high damping force until the stroke end is reached, and as a reaction, the force received by the support portion of the structure to which both ends of the cylinder device 10 are connected is received. I know it's strong.

  On the other hand, in the case where the first damping force switching mechanism 50 of the first embodiment is provided, when the piston 30 moves in the X1 direction and reaches the position immediately before contacting the first guide member 28, the first shaft member 54 and the first shaft member 54 The 1-valve portion 52 is pressed in the X2 direction which is the opposite direction to the piston moving direction. As a result, the spool 52a of the first valve portion 52 reaches the damping force switching position that intersects with the first communication passage 34 (see FIG. 4). That is, just before the piston 30 comes into contact with the first stopper portion 28 b, part of the working fluid pressurized in the first chamber 24 due to the movement of the piston 30 is transferred to the second chamber 26 via the first communication passage 34. Moving. As a result, the pressure in the first chamber 24 decreases, so that the damping forces of the first and second relief valves 100 and 110 and the first and second pressure regulating valves 120 and 130 also rapidly decrease as indicated by the slopes α and β. To do. Therefore, it is possible to prevent an excessive force from being applied to a support portion such as a structure to which the cylinder device 10 is attached.

  In FIG. 6, for example, when the inclination α in the first quadrant is due to the first damping force switching mechanism 50, the inclination β in the third quadrant is due to the second damping force switching mechanism 60.

  As described above, in the first embodiment, by providing the piston 30 with the first and second damping force switching mechanisms 50 and 60, the damping force is reduced at both stroke ends of the piston 30 that reciprocates in the cylinder 20. By doing so, it is possible to prevent an excessive force from acting on each support portion such as a structure to which the cylinder device 10 is attached.

  In addition, in the first embodiment, the shaft members 54 and 64 of the first and second damping force switching mechanisms 50 and 60 project in the axial direction (X1 and X2 directions) from the end surfaces 30a and 30b of the piston 30. It is possible to suppress damage to the outer periphery of the piston 30, the seal member that seals the outer periphery of the piston 30, and the like.

  In addition, in the above-described first embodiment, the case where the first valve portion 52 has the spool has been described as an example, but the present invention is not limited to this, and needless to say, another valve structure may be used. ..

  Further, in the above-described first embodiment, the case where the tip end portion of the first shaft member 54 contacts the first stopper portion 28b of the first guide member 28 has been described, but the present invention is not limited to this, and the first guide member is not limited thereto. Instead of 28, the tip portion of the first shaft member 54 may abut the inner wall of the lid member 25.

  Next, a second embodiment of the present invention will be described based on FIG. The same components as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and the description thereof will be omitted. Further, members having substantially the same function are denoted by reference numerals obtained by adding 200 to the reference numerals in the first embodiment.

  The cylinder 220 is roughly composed of a cylinder body 21 and first and second lid members 225 and 227 that close the ends thereof.

  A piston 230 is slidably fitted in the cylinder 220. A piston rod 240 including a first piston rod 242 and a second piston rod 244 is attached to the piston 230.

  Similar to the first embodiment, the piston 230 is provided with the first and second relief valves 100 and 110 and the first and second pressure regulating valves 120 and 130 in other cross sections.

  Further, the piston 230 is provided with the temperature compensation path 140 as in the first embodiment. The temperature compensation path 140 has a communication hole 146 penetrating the small diameter portion 242b of the first piston rod 242, and the communication hole 146 is communicated with the accumulator 260.

  In the temperature compensation path 140, a first valve 142 provided with an orifice 142a that opens and always communicates with the flow from the accumulator 260 to the first chamber 24, and from the accumulator 160 to the second chamber 26. And a second valve 144 which is provided with an orifice 144a which is open to the above flow and is always in communication with the second valve 144. Then, when the oil liquid in the first and second chambers 24, 26 thermally expands, the working fluid is recovered via the orifices 142a, 144a, and due to the contraction amount of the working fluid due to the temperature decrease or some other reason. The temperature compensating valve mechanism 90 is configured to replenish the oil liquid when the first and second chambers 24 and 26 have a negative pressure.

  Next, the damping force switching mechanism 250, which is a characteristic configuration of the second embodiment, will be described.

  The piston 230 is provided with a through hole 201 penetrating in the axial direction. The pin 202 is inserted into the through hole 201. Both ends of the pin 202 are in contact with the first and second lid members 225 and 227 and are not fixed. This prevents the pin 202 from being loaded even when the piston rod 240 rotates.

  The pin 202 has small-diameter portions 202a and 202c at both ends thereof, and has a large-diameter portion 202b having an outer diameter substantially equal to the inner diameter of the through hole at the central portion. The small diameter portions 202a and 202c are the shaft portions of the present invention, and the portion that expands from the small diameter portions 202a and 202c to the large diameter portion 202b is the valve portion. The small-diameter portions 202a and 202c may have the same diameter as the large-diameter portion 202b instead of having a small diameter as a whole, and may have a structure in which a slit is formed so that the outer circumference may have a partially small diameter.

  In the piston 230, a first connecting path 203 connected to the middle of the through hole 201 on the first chamber 24 side and a second connecting path 204 connecting to the middle of the second chamber 26 side are formed. The connection path 203 and the second connection path 204 are connected via the communication path 205, and are further connected to the temperature compensation path 140. The first seal 206 is provided on the first chamber 24 side of the first connection path 203, and the second seal 207 is provided on the first chamber 26 side of the second connection path 204, and the large diameter portion 202b is provided. When the seals 206 and 207 are in contact, the flow of the working fluid is blocked, and when the small diameter portions 202a and 202c face each other, the flow of the working fluid is allowed.

  In the second embodiment configured in this way, the working fluid in the first chamber 24 is in the small diameter portion near the stroke end where the piston 230 moves in the X1 direction and the seal 206 faces the small diameter portion 202a. Between the 202a and the through-hole 201, it flows into the second chamber 26 via the first connection path 203, the temperature compensation path 140, and the second valve 144. At this time, since the second valve 144 has a lower valve opening pressure than the first relief valve 100 and the first pressure regulating valve 120, a low damping force is generated.

  Further, in the vicinity of the stroke end where the piston 230 moves in the X2 direction and the seal 207 faces the small diameter portion 202c, the working fluid in the second chamber 26 is discharged between the small diameter portion 202c and the through hole 201, the second connection path 204, It flows into the first chamber 24 via the temperature compensation path 140 and the first valve 142. At this time, since the valve opening pressure of the first valve 142 is lower than that of the second relief valve 110 and the second pressure regulating valve 130, a low damping force is generated.

  Further, when the piston 230 is in the intermediate stroke, the through hole 201 is closed by the pin 202, and the first and second relief valves 100 and 110 and the first and second pressure regulating valves 120 and 130 provide high damping force. Occur.

  Therefore, also in the second embodiment, the attenuation characteristic shown in FIG. 6 is generated as in the first embodiment.

  Next, a third embodiment of the present invention will be described based on FIG. The same components as those in the first and second embodiments are designated by the same reference numerals as those in the first and second embodiments, and the description thereof will be omitted. Further, the members having substantially the same function are denoted by the numbers obtained by adding 300 to the reference numbers in the first embodiment.

  The third embodiment resides in that the pins 202 of the second embodiment are dispersed into two, and the others are the same.

  The cylinder 320 is roughly composed of the cylinder body 21 and first and second lid members 225 and 227 that close the ends thereof.

  Similar to the first embodiment, the piston 330 is provided with the first and second relief valves 100 and 110 and the first and second pressure regulating valves 120 and 130 in other cross sections.

  Further, the piston 330 is provided with the temperature compensation path 140 as in the first embodiment. The temperature compensation path 140 has a communication hole 146 penetrating the small diameter portion 242b of the first piston rod 242, and the communication hole 146 is communicated with the accumulator 260.

  In the temperature compensation path 140, there is provided a first valve 142 provided with an orifice 142a which is opened for constant flow from an accumulator 260 provided in a cross section different from that shown in FIG. 8 toward the first chamber 24, and an accumulator. There is provided a second valve 144 which is opened with respect to the flow from 260 to the second chamber 26 and which is provided with an orifice 144a which is always in communication with the second valve 144. Then, when the oil liquid in the first and second chambers 24, 26 thermally expands, the working fluid is recovered via the orifices 142a, 144a, and due to the contraction amount of the working fluid due to the temperature decrease or some other reason. The temperature compensating valve mechanism 90 is configured to replenish the oil liquid when the first and second chambers 24 and 26 have a negative pressure.

  Next, the damping force switching mechanism 350, which is a characteristic configuration of the third embodiment, will be described.

  The piston 330 is provided with a first through hole 301a and a second through hole 301b penetrating in the axial direction. Pins 302a and 302b are inserted into the through holes 301a and 301b, respectively.

  The first lid member 225 side of the pin 302a is a small diameter portion 302aa, and the opposite side is a large diameter portion 302ab. The second lid member 227 side of the pin 302b is a small diameter portion 302ba, and the opposite side is a large diameter portion 302bb. The small diameter portions 302aa and 302ba are the shaft portion of the present invention, and the portion that expands from the small diameter portion to the large diameter portion is the valve portion.

  In the piston 330, a first connecting path 303 is formed which is connected to the through hole 301a on the side of the first chamber 24, and the first connecting path 303 is connected to the temperature compensating path 140.

  In addition, a second connection path 304 that is connected in the middle of the through hole 301b on the second chamber 26 side is formed, and is connected to the temperature compensation path 140.

  In the third embodiment configured as described above, the piston 330 moves in the X1 direction, and the working fluid in the first chamber 24 is in the small diameter portion near the stroke end where the seal 206 faces the small diameter portion 302aa. Between the 302 aa and the through hole 301 a, the gas flows into the second chamber 26 via the first connection path 303, the temperature compensation path 140, and the second valve 144. At this time, since the second valve 144 has a lower valve opening pressure than the first relief valve 100 and the first pressure regulating valve 120, a low damping force is generated.

  Further, in the vicinity of the stroke end where the piston 330 moves in the X2 direction and the seal 207 faces the small diameter portion 302ba, the working fluid in the second chamber 26 flows between the small diameter portion 302ba and the through hole 301b, the second connecting passage 304, It flows into the second chamber 26 via the temperature compensation path 140 and the second valve 144. At this time, since the second valve 144 has a lower valve opening pressure than the second relief valve 110 and the second pressure regulating valve 130, a low damping force is generated.

  Further, when the piston 330 is in the intermediate stroke, the through holes 301a and 301b are closed by the pins 302a and 302b, and the first and second relief valves 100 and 110 and the first and second pressure regulating valves 120 and 130 are used. High damping force is generated.

  Therefore, also in the third embodiment, the attenuation characteristic shown in FIG. 6 is generated as in the first embodiment.

  Next, a fourth embodiment of the present invention will be described based on FIGS. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. Further, members having substantially the same function are denoted by the numbers obtained by adding 400 to the reference numbers in the first embodiment.

  The cylinder 420 is roughly composed of a cylinder body 421 and first and second lid members 425 and 427 that close the ends thereof.

  A piston 430 is slidably fitted in the cylinder 420. A piston rod 440 including a first piston rod 442 and a second piston rod 444 is attached to the piston 430.

  Similar to the first embodiment, the piston 430 is provided with the first and second relief valves 100 and 110 and the first and second pressure regulating valves 120 and 130 in other cross sections.

  Further, the piston 430 is provided with the temperature compensation path 140 as in the first embodiment. The temperature compensation path 140 has a communication hole 146 penetrating the small diameter portion 442b of the first piston rod 442, and the communication hole 146 is communicated with the accumulator 460.

  In the temperature compensating path 140, a first valve 142 provided with an orifice 142a that opens and always communicates with the flow from the accumulator 460 to the first chamber 24, and from the accumulator 160 to the second chamber 26. And a second valve 144 which is provided with an orifice 144a which is open to the above flow and is always in communication with the second valve 144. Then, when the oil liquid in the first and second chambers 24, 26 thermally expands, the working fluid is recovered via the orifices 142a, 144a, and due to the contraction amount of the working fluid due to the temperature decrease or some other reason. The temperature compensating valve mechanism 90 is configured to replenish the oil liquid when the first and second chambers 24 and 26 have a negative pressure.

  Next, the damping force switching mechanism 450, which is a characteristic configuration of the fourth embodiment, will be described.

  The piston 430 is provided with a through hole 401 penetrating in the axial direction. The through hole 401 communicates with the temperature compensation path 140.

  The piston 430 is provided with valve holes 402a and 402b that extend radially from the outer circumference toward the through hole 401 on the first chamber 24 side and the second chamber 26 side.

  Valve bodies 403a and 403b are slidably inserted into the valve holes 402a and 402b, respectively. The valve bodies 403a and 403b are urged radially outward by springs 404a and 404b. Further, when the valve bodies 403a and 403b move inward in the radial direction, the through hole 401 is blocked.

  Expanded portions 405a and 405c having an expanded inner diameter are formed on the inner peripheral surfaces of both ends of the cylinder 420, and a small diameter portion 405b having a diameter substantially the same as the outer diameter of the piston 430 is formed in the vicinity of the middle.

  In the fourth embodiment thus configured, when the piston 430 moves in the X1 direction and the valve body 403a faces the expanded diameter portion 405a, the spring 404a moves the valve body 403a radially outward. Then, the through hole 401 is brought into a communication state as shown in FIG.

  In such a state, the working fluid in the first chamber 24 flows into the second chamber 26 via the through hole 401, the temperature compensation path 140, and the second valve 144. At this time, since the second valve 144 has a lower valve opening pressure than the first relief valve 100 and the first pressure regulating valve 120, a low damping force is generated.

  Further, when the piston 430 moves in the X2 direction and the valve body 403b faces the expanded diameter portion 405c, the valve body 403b moves radially outward by the spring 404b, and the through hole 401 is brought into a communicating state. In such a state, the working fluid in the second chamber 26 flows into the first chamber 24 via the through hole 401, the temperature compensation path 140, and the first valve 142. At this time, since the second valve 144 has a lower valve opening pressure than the first relief valve 100 and the first pressure regulating valve 120, a low damping force is generated.

  Further, when the piston 430 is in the intermediate stroke, the through hole 401 is closed by the valve bodies 403a and 403b, and is higher than the first and second relief valves 100 and 110 and the first and second pressure regulating valves 120 and 130. A damping force is generated.

  Therefore, also in the fourth embodiment, the attenuation characteristic shown in FIG. 6 is generated as in the first embodiment.

10 Cylinder device 20 Cylinder 22 Cylinder chamber 24, 26 1st, 2nd chamber 25, 27 1st, 2nd lid member 28, 29 1st, 2nd guide member 28b, 29b 1st, 2nd stopper part 30 Piston 34 , 36 1st, 2nd communicating passage 40 Piston rod 42, 44 1st, 2nd piston rod 50, 60 1st, 2nd damping force switching mechanism 52, 62 1st, 2nd valve part 54, 64 1st, Second shaft member 56, 66 First, second spring member 70, 80 First, second check valve 90 Temperature compensation valve mechanism 100, 110 First, second relief valve 120, 130 First, second pressure regulating valve 140 temperature compensation path 150 relief path 160 accumulator

Claims (7)

A cylinder filled with working fluid,
A piston that defines the inside of the cylinder into a first chamber and a second chamber and slides in the cylinder;
A rod connected to the piston ,
Provided in the piston, and a communication passage which communicates with said second chamber and said first chamber,
A damping valve that opens by a pressure difference between the first chamber and the second chamber due to the movement of the piston to generate a damping force associated with the passage of the working fluid ;
A valve mechanism having a valve portion arranged at a position spaced apart from the central axis of the piston in a radial direction and increasing the passage area of the communication passage when the piston approaches the stroke end ;
Cylinder and wherein the kite comprising a. A cylinder filled with working fluid,
A piston that defines the inside of the cylinder into a first chamber and a second chamber and slides in the cylinder;
A rod connected to the piston,
A communication passage that is provided in the piston and that communicates the first chamber and the second chamber;
A damping valve that opens by a pressure difference between the first chamber and the second chamber due to the movement of the piston to generate a damping force associated with the passage of the working fluid;
A valve portion arranged at a position spaced apart from the central axis of the piston in the radial direction, and changing the passage area of the communication passage depending on the axial position of the piston, and the valve portion protruding axially from the end surface of the piston to the valve portion. A valve mechanism having a coupled shaft member ,
It features and to Resid cylinder device further comprising a.   The shaft member is provided integrally with the valve portion, and moves the valve portion in a piston moving direction by relative displacement caused by movement of the piston after contacting an inner wall of the cylinder. 2. The cylinder device according to item 2.   The cylinder according to claim 2 or 3, wherein the valve portion has a spool provided coaxially with the shaft member, and closes or opens the communication passage according to a moving position of the shaft member. apparatus. A cylinder filled with working fluid,
A piston that defines the inside of the cylinder into a first chamber and a second chamber and slides in the cylinder;
A rod connected to the piston,
A communication passage that is provided in the piston and that communicates the first chamber and the second chamber;
A damping valve that opens by a pressure difference between the first chamber and the second chamber due to the movement of the piston to generate a damping force associated with the passage of the working fluid;
A valve portion arranged at a position radially separated from the central axis of the piston and changing the passage area of the communication passage depending on the axial position of the piston; and a valve portion protruding radially from the outer peripheral surface of the piston to the valve portion. A valve mechanism having a coupled shaft member ,
It features and to Resid cylinder device further comprising a. An urging member for urging the shaft member in the protruding direction is provided,
The valve portion has a passage area before the tip of the shaft member abuts the inner wall of the cylinder by moving the tip of the shaft member abutting the inner wall of the end of the cylinder toward the piston side. The cylinder device according to any one of claims 2 to 5, wherein the cylinder device is made larger.   The cylinder device according to any one of claims 2 to 4, wherein the shaft member is provided on both sides in a moving direction of the valve portion and abuts on inner walls of end portions on both sides of the cylinder.

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