JP6514573B2 - Shock absorber - Google Patents

Description

  The present invention relates to improvements in shock absorbers.

  Conventionally, in a double cylinder type shock absorber for a vehicle, a cylinder, a piston slidably inserted in the cylinder, and a piston rod movably inserted in the cylinder and coupled to the piston; An annular reservoir provided between the expansion side chamber and pressure side chamber partitioned by the piston in the cylinder, the cylinder and the outer cylinder provided on the outer peripheral side of the cylinder, and the pressure side chamber and reservoir fitted with the end of the cylinder , An expansion-side port and a compression-side port provided on the piston to communicate the expansion-side chamber with the compression-side chamber, a check valve stacked on the expansion-side chamber of the piston to open and close the pressure-side port, and the pressure side of the piston An expansion side leaf valve stacked on the chamber side to open and close the expansion side port, an exhaust port and a suction port provided on the valve case for communicating the pressure side chamber with the reservoir, and pressure of the valve case A check valve for opening and closing the suction ports are stacked in the chamber side, and a pressure side leaf valve for opening and closing the exhaust port are stacked in the reservoir side of the valve case (e.g., see Patent Document 1).

  Then, at the time of contraction operation in which the shock absorber contracts, the piston rod intrudes into the cylinder and the hydraulic oil becomes excessive in the cylinder, so the excess hydraulic oil is discharged to the reservoir. Here, the valve case is provided with a stamped orifice in the valve seat on which the check valve for opening and closing the suction port is seated, and in the case where the shock absorber contracts at low speed, the hydraulic oil passes through the stamped orifice The pressure chamber then discharges into the reservoir.

  Therefore, in such a double cylinder type shock absorber, when the piston speed at the time of contraction is low, the damping force is exerted with a characteristic proportional to the square of the piston speed specific to the orifice. Then, when the piston speed becomes high, the pressure side leaf valve bends to bring the discharge port into communication, so the shock absorber switches from the characteristic peculiar to the orifice to the valve characteristic proportional to the piston speed to exert the damping force.

JP-A-8-177930 (FIG. 9)

  Thus, in the case of the double cylinder type shock absorber described above, in the case of contraction at a low speed, the damping force can be quickly raised with the orifice characteristic proportional to the square of the piston speed. However, in the conventional shock absorber, the pressure escapes to the reservoir through the orifice, and the pressure in the compression side chamber does not increase easily if the piston speed at the time of contraction is low. Is desired.

  Therefore, the present invention has been made to improve the above-mentioned problems, and the object of the present invention is to provide a shock absorber that improves the generation responsiveness of the pressure-side damping force.

  In order to solve the above-mentioned problems, the shock absorber in the solution means of the present invention is provided with an orifice connecting the expansion side chamber and the pressure side chamber, while the valve case only has the flow of the liquid from the pressure side chamber to the reservoir. Only a pressure-side damping valve that allows the flow of liquid to resist and a check valve that only allows the flow of liquid from the reservoir to the pressure-side chamber are provided. In this case, the pressure in the pressure side chamber is rapidly increased because the pressure does not directly escape from the pressure side chamber to the reservoir at the low speed range of the piston speed during the contraction operation.

  In addition, when the shock absorber has a single-acting pressure-side orifice that allows only the flow of liquid from the pressure-side chamber to the expansion-side chamber to resist the flow of liquid, excessive pressure rise in the pressure-side chamber is prevented However, independent tuning of the damping force characteristic becomes possible on both sides of the expansion and contraction.

  Further, the piston is provided with a port for communicating the expansion side chamber with the compression side chamber, and the first leaf valve having the compression side orifice leading to the port is opened and closed on the expansion side chamber side of the piston and the expansion side chamber of the first leaf valve By laminating a second leaf valve that opens and closes the pressure side orifice on the side, it is possible to configure a single-effect pressure side orifice with a simple configuration.

  In addition, if the second leaf valve includes an inner ring, an outer ring for opening and closing the pressure side orifice, and an arm for connecting the inner ring and the outer ring, the width of the arm and the setting number of the arms The valve opening pressure for opening the pressure side orifice can be easily tuned.

  According to the shock absorber of the present invention, it is possible to improve the generation responsiveness of the pressure-side damping force.

It is a longitudinal cross-sectional view of the buffer in one embodiment. It is an enlarged longitudinal cross-sectional view of the piston part of the shock absorber in one embodiment. It is a top view of the 1st leaf valve of the buffer in one embodiment. It is a top view of the 2nd leaf valve of a buffer in one embodiment. It is an expansion longitudinal cross-sectional view of the bottom part of the buffer in one embodiment. It is a figure showing the damping force characteristic at the time of contraction operation of the buffer in one embodiment.

  Hereinafter, the present invention will be described based on the embodiments shown in the drawings. As shown in FIG. 1, the shock absorber D in one embodiment includes a cylinder 1, a piston 2 slidably inserted in the cylinder 1, and a piston 2 movably inserted in the cylinder 1. A piston rod 3 to be connected, a valve case 4 separating the reservoir R and the liquid chamber L in the cylinder 1, an expansion side chamber R1 and a pressure side chamber R2 divided by the piston 2 in the liquid chamber L, and an expansion side chamber R1 It comprises an orifice O communicating with the pressure side chamber R2, and a pressure side damping valve 5 and a check valve 6 provided in the valve case 4.

  Further, in the case of the shock absorber D in the present embodiment, the reservoir R is formed between the cylinder 1 and the outer cylinder 7 provided on the outer periphery of the cylinder 1. Then, the cylinder 1 is filled with a liquid such as hydraulic oil, and the reservoir R is filled with a liquid and a gas. As the liquid, in addition to the hydraulic oil, for example, a liquid such as water or an aqueous solution can also be used.

  Each part will be described in detail below. A piston rod 3 is movably inserted into the cylinder 1, and a piston 2 is connected to the tip of the piston rod 3. Specifically, the piston rod 3 includes a small diameter portion 3a provided on the lower end side in FIG. 1 and a screw portion 3b provided on the outer periphery of the tip of the small diameter portion 3a. Further, the upper end side of the piston rod 3 in FIG. 1 is projected outward through the inside of an annular rod guide 10 mounted on the upper end of the cylinder 1 and the outer cylinder 7 in FIG. The rod guide 10 is provided with a cylindrical bush 11 on its inner periphery, and axially supports the piston rod 3 inserted in the bush 11 so that the axial movement of the piston rod 3 in the vertical direction in FIG. To guide you. Further, a seal member 12 for sealing between the cylinder 1 and the outer cylinder 7 and the piston rod 3 is stacked above the rod guide 10 in FIG. 1 so that the inside of the cylinder 1 is kept fluid tight.

  Further, an annular recess 10a in which a seal portion 12a slidably contacting the outer periphery of the piston rod 3 of the seal member 12 is provided on the inner periphery of the upper end in FIG. 1 of the rod guide 10. The annular recess 10a communicates with the reservoir R through a return passage 10b provided in the rod guide 10, and communicates with the expansion chamber R1 via a sliding gap between the bush 11 and the piston rod 3. At the lower end of the seal member 12 in FIG. 1, a check seal 12 b which can be attached to and detached from a stepped portion 10 c provided in the annular recess 10 a of the rod guide 10 is provided. When the check seal 12b is seated on the step 10c, the communication between the annular recess 10a and the return passage 10b is cut off, and when the pressure in the annular recess 10a becomes high, the check seal 12b bends and leaves the step 10c. The recess 10a is in communication with the reservoir R via the return passage 10b.

  In the cylinder 1, as shown in FIG. 2, a piston 2 connected to the piston rod 3 is slidably inserted. The piston 2 is provided with an annular disk portion 2a, a cylindrical portion 2b provided on the outer periphery of the disk portion 2a, and a plurality of disk portions 2a provided on the same circumference on the same circumference to communicate the expansion side chamber R1 The expansion side port 2c and a plurality of pressure side ports 2d provided on the same circumference on the same circumference and on the outer peripheral side than the expansion side port 2c are provided similarly, and the liquid chamber L in the cylinder 1 is an expansion side chamber. It divides into R1 and pressure side room R2.

  At the lower end in FIG. 2 of the disk portion 2a, the expansion side port 2c is projected downward in the drawing from the annular window 2e leading to the outlet end of each expansion side port 2c, and between the annular window 2e and the compression side port 2d. A surrounding annular expansion side valve seat 2f is provided. At the upper end of the piston 2 in FIG. 2, from an annular window 2g communicating with the inlet end of each expansion side port 2c, an annular window 2h communicating with the outlet end of each compression side port 2d, and between the annular window 2g and the annular window 2h An annular pressure side inner circumferential valve seat 2i protruding upward in the figure and an annular pressure side outer circumferential valve seat 2j projecting upward in the figure from the outer circumference of the annular window 2h and surrounding the outer circumferential side of the pressure side port 2d are provided.

  Further, at the lower end in FIG. 2 which is the pressure side chamber R2 side of the piston 2, there is stacked an expansion side leaf valve 8 which is seated on the expansion side valve seat 2f to open and close the expansion side port 2c. The expansion side leaf valve 8 is configured by laminating a plurality of annular leaf valves, and is assembled to the outer periphery of the small diameter portion 3a of the piston rod 3 together with the piston 2 and is a piston nut screwed to the screw portion 3b The small diameter portion 3a is mounted on the small diameter portion 3a. When the expansion side leaf valve 8 is attached to the small diameter portion 3a of the piston rod 3, the inner periphery is fixed and the outer periphery is allowed to bend. Further, among the leaf valves constituting the expansion side leaf valve 8, a leaf valve that is seated on the expansion side valve seat 2f is provided with a notch, and the orifice O is formed by the cutout. Then, at the time of the extension operation of the shock absorber D, the expansion side leaf valve 8 is kept in the sitting state on the expansion side valve seat 2f until the pressure of the expansion side chamber R1 acting via the expansion side port 2c reaches the valve opening pressure. However, the liquid can move from the expansion chamber R1 to the compression chamber R2 via the orifice O. On the other hand, when the pressure of the expansion side chamber R1 acting via the expansion side port 2c reaches the valve opening pressure during the expansion operation of the shock absorber D, the expansion side leaf valve 8 is released from the expansion side valve seat 2f. Then open the expansion port 2c. Further, when the shock absorber D is contracted, the expansion side leaf valve 8 is pressed against the expansion side valve seat 2f by the pressure of the pressure side chamber R2 to be in a sitting state, but the liquid is compressed from the pressure side chamber R2 through the orifice O It can move to R1. That is, this orifice O is a dual action orifice that allows the passage of liquid on both sides of the expansion operation and contraction operation of the shock absorber D, that is, both sides of the expansion pressure. The orifice O may be formed as a recess provided by being stamped on the expansion side valve seat 2f. The structure of the piston 2 is an example and is not limited to the above, and the arrangement and shape of the expansion side port 2c and the compression side port 2d can be changed, and the shape of each valve seat is also annular. It is also possible to adopt a petal type. Instead of the expansion side leaf valve 8, another valve such as a poppet valve may be used to open and close the expansion side port 2c.

  At the upper end in FIG. 2 which is the expansion side chamber R1 side of the piston 2, a pressure side leaf valve 9 is stacked which is seated on the pressure side inner peripheral valve seat 2i and the pressure side outer peripheral valve seat 2j to open and close the pressure side port 2d. The pressure side leaf valve 9 is stacked on the upper side in FIG. 2 which is the side of the expansion side chamber R1 of the first leaf valve 14 and the annular first leaf valve 14 that is seated on the pressure side inner peripheral valve seat 2i and the pressure side outer peripheral valve seat 2j. And an annular second leaf valve 15.

  As shown in FIG. 3, the first leaf valve 14 is annular, and has a compression side orifice consisting of seven holes 14a opposed to the annular window 2g provided in the piston 2 and one small hole opposed to the annular window 2h. And 14b. Further, as shown in FIG. 4, the second leaf valve 15 is annular, and is an outer ring 15b disposed on the outer ring side of the inner ring 15a and the inner ring 15a and having a larger inner diameter than the inner ring 15a; And three arms 15c connecting the outer ring 15b. And three arc-shaped holes 15d are formed between the inner ring 15a and the outer ring 15b. The arcuate hole 15 d is provided at a position facing the hole 14 a when the second leaf valve 15 is stacked on the first leaf valve 14. Note that the number and width of the arms 15c can be set as desired in consideration of not blocking most of the holes 14a.

Therefore, when the first leaf valve 14 and the second leaf valve 15 are stacked on the piston 2, the hole 14a faces the annular window 2g, the arc-like hole 15d faces the hole 14a, and the expansion side chamber R1 of the expansion side port 2c Communication with is secured. Further, when the first leaf valve 14 and the second leaf valve 15 are stacked on the piston 2, the pressure side orifice 14 b is closed by the outer ring 15 b of the second leaf valve 15.

  And, the pressure side leaf valve 9 configured in this way is attached to the outer periphery of the small diameter portion 3a of the piston rod 3 together with the piston 2, and mounted on the small diameter portion 3a by the piston nut 13 screwed to the screw portion 3b. Ru. When the first leaf valve 14 and the second leaf valve 15 are mounted on the small diameter portion 3 a of the piston rod 3, the inner periphery is fixed together and the outer periphery is allowed to bend. Therefore, when the pressure of pressure side room R2 which acts via pressure side port 2d reaches valve-opening pressure at the time of contraction operation of shock absorber D, the 1st leaf valve 14 and the 2nd leaf valve 15 bend together, and pressure side port 2d Is released.

  Here, the second leaf valve 15 has a structure in which the outer ring 15b is connected to the inner ring 15a fixed to the small diameter portion 3a by the arm portion 15c whose circumferential width is narrower than the arc-shaped hole 15d. Therefore, the rigidity is low and it is easy to bend as compared with the first leaf valve 14. By this, before the first leaf valve 14 and the second leaf valve 15 both bend and open the pressure side port 2 d, the pressure of the pressure side chamber R2 causes the outer ring 15 b to face the pressure side orifice 14 b from the first leaf valve 14 The separated pressure side orifice 14b can be opened. On the other hand, at the time of extension operation of the shock absorber D, the second leaf valve 15 is pressed against the first leaf valve 14 by the pressure of the expansion side chamber R1, the outer ring 15b does not separate from the first leaf valve 14 and the pressure side orifice 14b Shut up. Therefore, the pressure side orifice 14b allows only the flow of the liquid from the pressure side chamber R2 to the expansion side chamber R1 and gives resistance to the flow of the liquid. It functions as an effective orifice.

  The valve case 4 is fitted to the lower end of the cylinder 1, is held between the outer cylinder 7 and the cylinder 1 and is fixed to the lower end of the cylinder 1 in FIG. A reservoir R formed between the outer cylinder 7 and the outer cylinder 7 is partitioned. And, as shown in FIG. 5, the valve case 4 has an annular shape, and is provided on the same circumference, and a plurality of suction ports 4a communicating the pressure side chamber R2 and the reservoir R, and the suction port 4a inside A plurality of discharge ports 4 b provided on the same circumference on the same circumference and communicating the pressure side chamber R 2 with the reservoir R are provided.

  Further, at the lower end of the valve case 4 in FIG. 5, an annular window 4c communicating with the outlet end of each discharge port 4b, and an annular shape which protrudes downward in the figure from between the annular window 4c and the suction port 4a and surrounds the discharge port 4b. The discharge side valve seat 4d is provided. At the upper end of the valve case 4 in FIG. 5, an annular window 4e communicating with the inlet end of each discharge port 4b, an annular window 4f communicating with the outlet end of each suction port 4a, and between the annular window 4e and the annular window 4f An annular suction side inner peripheral valve seat 4g protruding upward in the drawing and an annular suction side outer peripheral valve seat 4h protruding upward in the drawing from the outer periphery of the annular window 4f and surrounding the outer peripheral side of the suction port 4a are provided. .

  Furthermore, at the lower end in FIG. 5 which is the reservoir R side of the valve case 4, a pressure side damping valve 5 is stacked which is seated on the discharge side valve seat 4 d and opens and closes the discharge port 4 b. The compression side damping valve 5 is configured by laminating a plurality of annular leaf valves, and is assembled on the outer periphery of the assembly rod 16 inserted into the inner periphery of the valve case 4 and at the tip of the assembly rod 16 The assembly rod 16 is attached to the assembly rod 16 by means of a nut 17 screwed onto the provided screw portion 16a.

  When the compression side damping valve 5 is attached to the assembling rod 16, the inner periphery is fixed and the outer periphery is allowed to bend. Then, when the pressure of the pressure side chamber R2 acting through the discharge port 4b reaches the valve opening pressure at the time of contraction operation of the shock absorber D, the pressure side damping valve 5 separates from the discharge side valve seat 4d and the discharge port Open 4b. Thus, at the time of contraction operation of the shock absorber D, the pressure side damping valve 5 opens the discharge port 4b, and the liquid can move from the pressure side chamber R2 to the reservoir R. Further, at the time of the extension operation of the shock absorber D, the piston rod 3 retracts from the cylinder 1 and the volume of the pressure side chamber R2 is expanded, so the pressure of the pressure side chamber R2 is equal to the valve opening pressure of the pressure side damping valve 5 And the discharge port 4b is maintained in the closed state. Thus, the pressure-side damping valve 5 allows only the flow of the liquid from the pressure-side chamber R2 to the reservoir R to resist the flow of the liquid.

  On the other hand, at the upper end in FIG. 5 which is the pressure side chamber R2 side of the valve case 4, there is stacked a check valve 6 which is seated on the suction side inner peripheral valve seat 4g and the suction side outer peripheral valve seat 4h to open and close the suction port 4a. It is done. In this example, the check valve 6 is configured to include two annular plates 6 a that are seated on and separated from the suction side inner circumferential valve seat 4 g and the suction side outer circumferential valve seat 4 h, and assembled on the outer periphery of the assembly rod 16. It is attached and attached to the assembly rod 16 by a nut 17. Further, the check valve 6 is configured to ensure the communication between the pressure side chamber R2 and the discharge port 4b by the through hole 6b provided in the annular plate 6a.

  When the check valve 6 is attached to the assembly rod 16, the inner periphery is fixed and the outer periphery is allowed to bend. Then, at the time of the extension operation of the shock absorber D, as the piston rod 3 is withdrawn from the cylinder 1, the pressure side chamber R2 is depressurized and is opened by the pressure of the reservoir R, and the suction port 4a is opened. Thus, at the time of the extension operation of the shock absorber D, the check valve 6 opens the suction port 4a, and the liquid can be moved from the reservoir R to the pressure side chamber R2. Further, at the time of the contraction operation of the shock absorber D, the check valve 6 is pressed against the valve case 4 by the pressure of the pressure side chamber R2 that increases the pressure, so the suction port 4a is maintained in the closed state. Thus, the check valve 6 allows only the flow of liquid from the reservoir R to the pressure side chamber R2. The structure of the valve case 4 is an example and is not limited to the above, and the arrangement and shape of the suction port 4a and the discharge port 4b can be changed, and the shape of each valve seat is also annular. It is also possible to adopt a petal type.

  In order to prevent sticking of the discharge side valve seat 4d and the pressure side damping valve 5 and sticking of the suction side outer peripheral valve seat 4h and the check valve 6, the contact surface of the discharge side valve seat 4d to the pressure side damping valve 5 and suction The surface roughness is roughened by subjecting the contact surface of the side outer peripheral valve seat 4 h to the check valve 6 to a matte finish or the like. Instead of roughening the surface roughness described above, the discharge side valve seat 4d, the pressure side damping valve 5, the suction side outer peripheral valve seat 4h or the check valve 6 is attached to allow passage of a very small amount of liquid even when the valve is closed. Even in the case of providing the prevention notch or the like, the valve case 4 is not provided with the orifice. The purpose of providing only the pressure side damping valve 5 and the check valve 6 in the valve case 4 is to exclude the provision of the orifice in the pressure side damping valve 5 and the check valve 6.

  The shock absorber D is configured as described above, and its operation will be described below. First, an operation at the time of the extension operation of the shock absorber D in which the piston 2 moves upward in FIG. 1 with respect to the cylinder 1 will be described. At the time of the extension operation of the shock absorber D, since the piston 2 compresses the expansion side chamber R1, the liquid tends to move from the expansion side chamber R1 to the pressure side chamber R2. Further, since the piston rod 3 is withdrawn from the inside of the cylinder 1, the liquid of the withdrawal volume of the piston rod 3 runs short in the cylinder 1. When the piston speed, which is the moving speed of the piston 2 with respect to the cylinder 1, is low, the pressure in the expansion chamber R1 does not reach the opening pressure of the expansion leaf valve 8 and the pressure side orifice 14b is the second leaf as described above. It is maintained in the closed state by the valve 15. Therefore, in this case, the liquid passes through the orifice O and moves from the expansion side chamber R1 to the pressure side chamber R2.

  On the other hand, the liquid lacking in the cylinder 1 is supplied from the reservoir R to the pressure side chamber R2 through the suction port 4a by opening the check valve 6. Therefore, the pressure in the expansion side chamber R1 increases, and the pressure in the pressure side chamber R2 becomes substantially a reservoir pressure, so that a differential pressure is generated in both chambers, and the shock absorber D exerts a damping force to suppress the extension operation. . In this case, the damping force characteristic of the shock absorber D is an orifice-specific characteristic in which the slope increases in proportion to the square of the velocity as the piston velocity increases. When the piston speed reaches the high speed region, the pressure in the expansion side chamber R1 reaches the opening pressure of the expansion side leaf valve 8 to be opened, the expansion side port 2c is opened, and the liquid passes therethrough. Thus, the damping force characteristic of shock absorber D is a valve-specific characteristic that is proportional to the increase in piston speed.

  On the contrary, the operation at the time of contraction operation of shock absorber D which piston 2 moves below in Drawing 1 to cylinder 1 is explained. Since the piston 2 compresses the pressure side chamber R2 at the time of contraction operation of the shock absorber D, the liquid tends to move from the pressure side chamber R2 to the expansion side chamber R1. When the piston speed, which is the moving speed of the piston 2 relative to the cylinder 1, is low, the pressure in the pressure side chamber R2 does not reach the valve opening pressure of the pressure side leaf valve 9 and the pressure side damping valve 5, and the outer ring 15b of the second leaf valve 15 The pressure side orifice 14 b is opened apart from the first leaf valve 14. Accordingly, the liquid moves from the pressure side chamber R2 to the expansion side chamber R1 through the orifice O and the pressure side orifice 14b. Although the piston rod 3 intrudes into the cylinder 1 and the liquid invading the piston rod 3 in the cylinder 1 becomes excessive, the pressure in the expansion side chamber R1 increases the pressure in the annular recess 10a, The check seal 12 b opens to allow excess liquid to escape to the reservoir R. As described above, when the shock absorber D is contracted and the piston speed is low, since the liquid in the pressure side chamber R2 separates the pressure side chamber R2 from the reservoir R, no orifice is provided in the valve case 4 , Does not move directly to the reservoir R. Therefore, when the shock absorber D is in contraction and the piston speed is low, pressure does not directly escape from the pressure side chamber R2 to the reservoir R, so the pressure in the pressure side chamber R2 rises rapidly. Therefore, the damping force characteristic (the characteristic of the damping force with respect to the piston speed) of shock absorber D in this case is, as shown in FIG. It becomes a characteristic close to the characteristic, and becomes a characteristic in which the damping force rises with good response. As described above, according to the shock absorber D of the present invention, it is possible to improve the generation responsiveness of the pressure-side damping force. Even when the check seal 12b is not provided, the pressure increase in the pressure side chamber R2 does not change at the point where the pressure increase rapidly, so that the damping force generation responsiveness at the time of the contraction operation in the shock absorber D is improved.

  Further, in the case where only the improvement of the generation response of the pressure-side damping force of the shock absorber D is intended, the pressure-side orifice 14b may be omitted. However, if the pressure side orifice 14b having a single effect that is effective only during the contraction operation is provided, it is possible to tune the damping force characteristics independently on both sides of the expansion and contraction while preventing an excessive pressure rise in the pressure side chamber R2. .

  Further, the piston 2 is provided with a port 2d for communicating the expansion side chamber R1 with the pressure side chamber R2, and the first leaf valve 14 having the pressure side orifice 14b communicating with the port 2d is opened and closed on the expansion side chamber R1 side of the piston 2 When the second leaf valve 15 that stacks and opens and closes the pressure side orifice 14b on the expansion side chamber R1 side of the first leaf valve 14 is stacked, the pressure side orifice 14b having a single effect can be configured with a simple configuration. The configuration of the pressure-side orifice is not limited to the above-described configuration, and a valve having a structure other than the pressure-side leaf valve 9 may be used to open and close the pressure-side port 2d. For example, when communication between the expansion side chamber R1 and the pressure side chamber R2 is ensured by the pressure side orifice, the pressure side port 2d may not be used but may be independently communicated with it. The valve may be independent without being integrated into the valve.

  Further, when the second leaf valve 15 includes the inner ring 15a, the outer ring 15b for opening and closing the pressure side orifice 14b, and the arm portion 15c for connecting the inner ring 15a and the outer ring 15b, the arm portion By setting the width 15c and the number of installation, the valve opening pressure for opening the pressure side orifice 14b can be easily tuned.

  Returning back, when the piston speed reaches the high speed region, the pressure in the pressure side chamber R2 reaches the valve opening pressure of the pressure side leaf valve 9 and the pressure side damping valve 5, opens, and the pressure side port 2d and the discharge port 4b are opened. . In this case, the liquid moves from the pressure side chamber R2 to the expansion side chamber R1 via the pressure side port 2d and also to the reservoir R via the discharge port 4b. Then, the damping force characteristic of the shock absorber D is, as shown in FIG. 7, characteristic of the liquid passing through the orifice O and the pressure side orifice 14b, the valve characteristic is proportional to the increase of the piston speed although the inclination is smaller. It becomes the characteristic of

  This completes the description of the embodiments of the present invention, but it is to be understood that the scope of the present invention is not limited to the exact details shown or described.

1 · · · · · · · · · · · · · · · · · · · · · 2 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Valve 14 14 first leaf valve 14 b pressure side orifice 15 second leaf valve 15 a inner ring 15 b outer ring 15 c arm D · · Buffer, L · · · Liquid chamber, O · · · · · · · · · · · · · · · Reservoir, R1 · · · extension side chamber, R2 · · · pressure side chamber,

Claims (3)

With the cylinder,
A piston slidably inserted in the cylinder;
A piston rod movably inserted into the cylinder and coupled to the piston;
A valve case separating the reservoir and a liquid chamber in the cylinder;
An expansion side chamber and a pressure side chamber partitioned by the piston in the liquid chamber;
An orifice communicating the expansion side chamber with the pressure side chamber ;
And a single-acting pressure-side orifice that provides resistance to the flow of liquid while allowing communication between the expansion-side chamber and the pressure-side chamber, and allowing only the flow of liquid from the pressure-side chamber toward the expansion-side chamber ;
A pressure-side damping valve that allows only the flow of liquid from the pressure-side chamber to the reservoir to resist the flow of liquid, and a non-return that allows only the flow of liquid from the reservoir to the pressure-side chamber in the valve case A shock absorber characterized in that only a valve is provided. The piston has a port communicating the expansion side chamber with the pressure side chamber.
A first leaf valve having the compression side orifice which is stacked on the expansion side chamber side of the piston to open and close the port and which is a small hole communicating with the port;
2. The shock absorber according to claim 1 , further comprising: a second leaf valve stacked on the expansion side chamber side of the first leaf valve to open and close the pressure side orifice. The second leaf valve includes an inner ring, an outer ring disposed on the outer peripheral side of the inner ring to open and close the pressure-side orifice, and an arm portion connecting the inner ring and the outer ring. The shock absorber according to claim 2 , characterized in that.

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