JP2022087486A - Shock absorber - Google Patents

Abstract

To provide a shock absorber capable of improving the generation responsiveness of damping force.SOLUTION: A shock absorber D includes a cylinder 1, a rod 2 movably inserted into the cylinder 1, a piston 3 movably inserted into the cylinder 1 for partitioning the cylinder 1 into an extension side chamber R1 and a pressure side chamber R2, a reservoir R storing fluid, an extension side discharge passage 4 connected at one end to the extension side chamber R1 for allowing only the flow of the fluid from the extension side chamber R1 to the other end side, a pressure side discharge passage 5 connected at one end to the pressure side chamber R2 for allowing only the flow of the fluid from the pressure side chamber R2 to the other end side, a common discharge passage 6 connecting the other end of the extension side discharge passage 4 and the pressure side discharge passage 5 to the reservoir R, an extension and pressure common damping valve 7 provided in the common discharge passage 6, an extension side suction passage 8 for allowing only the flow of the fluid from the reservoir R to the extension side chamber R1, and a pressure side suction passage 9 for allowing only the flow of the fluid from the reservoir R to the pressure side chamber R2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a shock absorber.

The shock absorber is interposed between the vehicle body and the wheels of the vehicle and exerts a damping force to suppress the vibration of the vehicle body and the wheels. The damping force exerted by the shock absorber is exerted by the damping valve and affects the riding comfort in the vehicle.

Such a shock absorber is, for example, a cylinder, a rod movably inserted into the cylinder, and an extension chamber connected to the rod and movably inserted into the cylinder and filled with hydraulic oil in the cylinder. A piston that divides the pressure side chamber and the compression side chamber, a reservoir having a liquid chamber for storing liquid and an air chamber for pressurizing the liquid chamber, a first passage connecting the extension side chamber and the liquid chamber, and a compression side chamber and a liquid chamber. The second passage, the extension side damping valve and the first check valve provided in parallel with the first passage, and the compression side damping valve and the second check valve provided in parallel with the second passage are provided. (See, for example, Patent Document 1).

The first check valve allows only the flow of hydraulic oil from the extension chamber to the reservoir, and the second check valve allows only the flow of hydraulic oil from the compression concubine to the reservoir.

Therefore, in the shock absorber configured in this way, when the extension operation is performed in which the piston moves in the direction of compressing the extension side chamber with respect to the cylinder, the hydraulic oil in the extension side chamber to be compressed causes the extension side damping valve and the second check valve. It moves to the compression side chamber that expands through it, and the extension side damping valve generates an extension side damping force that hinders the extension operation.

On the other hand, in the shock absorber, during the contraction operation in which the piston moves in the direction of compressing the compression side chamber with respect to the cylinder, the hydraulic oil in the compression side chamber to be compressed expands through the compression side damping valve and the first check valve. It moves to the side chamber and generates a compression side damping force that hinders the contraction operation by the compression side damping valve.

Therefore, the conventional shock absorber can send the hydraulic oil equal to the volume fluctuation of the compressed side chamber to the compression side damping valve even during the contraction operation, and is effective when generating the compression side damping force. The pressure receiving area of the piston can be increased. In a general double-cylinder shock absorber, only the volume of hydraulic oil that the rod enters the cylinder during contraction can be sent to the compression side damping valve, and the pressure receiving area of the piston is also large due to the limitation of the rod diameter. It's hard. Therefore, the conventional shock absorber can increase the amount of hydraulic oil passing through the compression side damping valve at the time of contraction operation and can secure a large pressure receiving area of the piston as compared with a general double cylinder type shock absorber, which is large. Can exert damping force.

U.S. Pat. No. 7,607,522

When the conventional shock absorber is extended, the hydraulic oil passes through the first passage and the second passage in order and moves from the extension side chamber to the compression side chamber, and when the conventional shock absorber is contracted, the hydraulic oil is the first. It moves from the compression side chamber to the extension side chamber by passing through the second passage and the first passage in order.

As described above, in the conventional shock absorber, the flow of the hydraulic oil passing through the first passage and the second passage is reversed in order to switch from the extension operation to the contraction operation or from the contraction operation to the extension operation, but the operation is performed. The flow of hydraulic oil cannot be reversed instantly due to the influence of compressibility and inertia due to the oil containing gas. Therefore, the conventional damping force has a problem that the generation of the damping force is delayed at the switching of the expansion / contraction operation, and it is required to improve the generation response of the damping force.

Therefore, an object of the present invention is to provide a shock absorber capable of improving the generation response of the damping force.

In order to solve the above-mentioned problems, the shock absorber of the present invention has a cylinder, a rod that is movably inserted into the cylinder, a rod that is connected to the rod and is movably inserted into the cylinder, and a liquid in the cylinder. A piston that divides the extension chamber and the compression side chamber into which the liquid is filled, a reservoir that stores the liquid, and an extension side discharge that is connected to the extension side chamber at one end and allows only the flow of liquid from the extension side chamber to the other end side. The passage, one end is connected to the compression side chamber and the compression side discharge passage allows only the flow of liquid from the compression side chamber to the other end side, and one end is the other end of the extension side discharge passage and the other end of the compression side discharge passage. A common discharge passage that is connected and the other end is connected to the reservoir, a compression common damping valve provided in the common discharge passage, an extension side suction passage that allows only the flow of liquid from the reservoir to the extension side chamber, and a reservoir. It is characterized by having a compression side suction passage that allows only the flow of liquid from the compression side chamber to the compression side chamber.

In the shock absorber configured in this way, the liquid always flows in the same direction only in the common discharge passage when the shock absorber expands and contracts, and flows in one way through the extension side discharge passage and the compression side suction passage when the shock absorber expands, and the shock absorber During contraction, it flows one way through the compression side discharge passage and the extension side suction passage. Therefore, the liquid does not flow in the same passage in the reverse direction when the shock absorber is expanded and contracted, and the closing delay of various valves arranged in each passage does not occur.

Further, the shock absorber may be provided with a common check valve provided in the common discharge passage and allowing only the flow of liquid from one end of the common discharge passage toward the reservoir side. According to the shock absorber configured in this way, the backflow of the liquid from the liquid chamber to the common discharge passage side can be prevented, and the disturbance of the damping force can be prevented, so that the riding comfort in the vehicle can be further improved.

Further, the shock absorber may include an extension side damping valve provided in the extension side discharge passage and a compression side damping valve provided in the compression side discharge passage. According to the shock absorber configured in this way, the extension side damping force is generated by the extension side damping valve and the extension common damping valve during extension, and the compression side damping force is generated by the compression side damping valve and the extension common damping valve during contraction. Is generated, so that the extension side damping force and the compression side damping force can be set independently.

Further, the shock absorber may be provided with a relief valve arranged in parallel with the extension pressure common damping valve in the common discharge passage. According to the shock absorber configured in this way, it is possible to set the damping force characteristics when the piston speed when the piston moves with respect to the cylinder is in the low speed range with the extension side damping valve and the compression side. With the damping valve, the damping force characteristics can be set when the piston speed is in the high speed range exceeding the low speed range.

Further, when the extension pressure common damping valve in the shock absorber is a variable damping valve, the damping force on the extension side and the compression side can be adjusted at the same time so as to be suitable for suppressing the vibration of the vehicle body to be applied.

From the above, according to the shock absorber of the present invention, it is possible to improve the generation response of the damping force.

It is a vertical sectional view of the shock absorber in one Embodiment. It is a figure which showed an example of the check valve of the shock absorber in one Embodiment. It is sectional drawing of the shock absorber in the 1st modification of one Embodiment. It is sectional drawing of the shock absorber in the 2nd modification of one Embodiment. It is a figure which showed the damping force characteristic of the shock absorber in the 2nd modification of one Embodiment.

Hereinafter, the present invention will be described based on the embodiments shown in the figure. As shown in FIG. 1, the shock absorber D in one embodiment has a cylinder 1, a rod 2 movably inserted into the cylinder 1, and a rod 2 connected to the rod 2 and movably inserted into the cylinder 1. A piston 3 that divides the inside of the cylinder 1 into an extension side chamber R1 and a compression side chamber R2, a reservoir R that stores the liquid, and one end connected to the extension side chamber R1 and the other end from the extension side chamber R1. An extension side discharge passage 4 that allows only the flow of liquid toward the side, and a compression side discharge passage 5 that is connected to the compression side chamber R2 at one end and allows only the flow of liquid from the compression side chamber R2 toward the other end side. Is connected to the other end of the extension side discharge passage 4 and the other end of the compression side discharge passage 5, and the other end is connected to the reservoir R. 7 is provided with an extension-side suction passage 8 that allows only the flow of liquid from the reservoir R to the extension-side chamber R1, and a compression-side suction passage 9 that allows only the flow of liquid from the reservoir R to the compression-side chamber R2. In the case of this shock absorber D, it is used by being interposed between the vehicle body and the axle in a vehicle (not shown), and suppresses vibration of the vehicle body and wheels.

Hereinafter, each part of the shock absorber D will be described in detail. As shown in FIG. 1, the cylinder 1 has a cylindrical shape, the upper end of FIG. 1 is closed by an annular rod guide 19, and the lower end of FIG. 1 is closed by a cap 20.

Further, the inside of the cylinder 1 is divided into an extension side chamber R1 in the upper part in FIG. 1 and a compression side chamber R2 in the lower part in FIG. 1 by a piston 3 movably inserted into the cylinder 1. The extension side chamber R1 and the compression side chamber R2 are filled with a liquid such as hydraulic oil. In addition to the hydraulic oil, a liquid such as water or an aqueous solution can also be used as the liquid.

The rod 2 is movably inserted into the cylinder 1 through the inner circumference of the rod guide 19 in the vertical direction which is the central axis direction of FIG. 1, and the piston 3 is connected to the tip thereof. Therefore, when the rod 2 moves in the axial direction with respect to the cylinder 1, the piston 3 connected to the rod 2 also moves in the axial direction with respect to the cylinder 1 to compress and stretch one of the extension side chamber R1 and the compression side chamber R2. The other side of the side chamber R1 and the compression side chamber R2 is enlarged. The outer circumference of the rod 2 is slidably contacted with the inner circumference of the rod guide 19, and the rod guide 19 and the piston 3 guide the rod 2 to move in the axial direction with respect to the cylinder 1. The shock absorber D of the present embodiment is configured as a so-called single rod type shock absorber in which the rod 2 is inserted only in the extension side chamber R1, but the rod 2 is not only in the extension side chamber R1 but also in the compression side chamber R1. It may be configured as a so-called double-rod type shock absorber that is also inserted in R2.

An outer cylinder 10 that covers the outer circumference of the cylinder 1 is provided on the outer circumference of the cylinder 1. Further, the upper end of the outer cylinder 10 in FIG. 1 is closed by fitting the rod guide 19, and the lower end of the outer cylinder 10 in FIG. 1 is closed by the cap 20. Then, the annular gap S formed between the cylinder 1 and the outer cylinder 10 is communicated with the extension side chamber R1 in the cylinder 1 through the through hole 1a provided near the upper end in FIG. 1 of the cylinder 1. There is.

The reservoir R is filled with a cylindrical reservoir tank 11 in which both ends are closed, a liquid chamber L in which the reservoir tank 11 is movably inserted in the axial direction and the inside of the reservoir tank 11 is filled with a liquid, and a gas. It is configured to include an air chamber G and a free piston 12 for partitioning. A high-pressure gas that is inert as a gas is sealed in the air chamber G, and the pressure in the air chamber G acts on the liquid chamber L via the free piston 12, and the liquid chamber L is pressurized. .. In the shock absorber D of the present embodiment, the reservoir R is divided into a liquid chamber L and an air chamber G by a free piston 12, but instead of the free piston 12, a diaphragm or a bellows is used to divide the reservoir R into the liquid chamber L. It may be partitioned into room G. Further, when the common discharge passage 6, the extension side suction passage 8, and the compression side suction passage 9, which will be described later, are connected to the lower ends of the reservoir tank 11 and there is no risk of gas entering the cylinder, a free piston 12, a diaphragm, a bellows, etc. The member for partitioning the chamber G can be omitted. Further, in the shock absorber D of the present embodiment, the high pressure gas is sealed in the air chamber G, but instead of filling the high pressure gas, a spring that urges the free piston 12 in the direction of compressing the liquid chamber L. An elastic body such as the above may be provided.

One end of the extension side discharge passage 4 is connected to the extension side chamber R1, and the other end is drawn out of the outer cylinder 10. Specifically, in the shock absorber D of the present embodiment, the extension side discharge passage 4 is configured to include a through hole 1a, an annular gap S, and a conduit 13 leading to an end surface facing the annular gap S of the cap 20. ing. Since one end of the extension side discharge passage 4 may be connected to the extension side chamber R1 and the other end may be connected to the common discharge passage 6 described later, the specific configuration of the passage can be changed as appropriate.

The extension side discharge passage 4 is provided with a check valve 16 that allows only the flow of liquid from the extension side chamber R1 toward the other end side, and an extension side damping valve 14 that resists the flow of the passing liquid. The extension side discharge passage 4 is set as a one-way passage that allows only the flow of liquid from the extension side chamber R1 toward the other end side by installing the check valve 16. The extension side damping valve 14 is a variable throttle valve, and the resistance given to the flow of the passing liquid can be adjusted by adjusting the opening area. Further, the extension side damping valve 14 may be a damping valve having a check function that allows only the flow of liquid from the extension side chamber R1 toward the other end side and gives resistance to the flowing liquid flow. Since the extension side discharge passage 4 can be set as a one-way passage, the check valve 16 can be omitted. As described above, in order to set the extension side discharge passage 4 as a one-way passage, the extension side damping valve 14 that allows only the flow of the liquid from one direction may be used, or the extension side damping valve 14 may be both of the liquid. If the valve allows forward flow, the check valve 16 may be used.

One end of the compression side discharge passage 5 is connected to the compression side chamber R2, and the other end is drawn out of the outer cylinder 10. Specifically, in the shock absorber D of the present embodiment, the compression side discharge passage 5 is formed by a conduit leading to the end surface of the cap 20 facing the compression side chamber R2. Since one end of the compression side discharge passage 5 may be connected to the compression side chamber R2 and the other end may be connected to the common discharge passage 6 described later, the specific configuration of the passage can be appropriately changed.

The compression side discharge passage 5 is provided with a check valve 17 that allows only the flow of liquid from the compression side chamber R2 toward the other end side, and a compression side damping valve 15 that resists the flow of the passing liquid. The compression side discharge passage 5 is set as a one-way passage that allows only the flow of liquid from the compression side chamber R2 toward the other end side by installing the check valve 17. The compression side damping valve 15 is a variable throttle valve, and the resistance given to the flow of the passing liquid can be adjusted by adjusting the opening area. Further, the compression side damping valve 15 may be a damping valve having a check function that allows only the flow of liquid from the compression side chamber R2 toward the other end side and gives resistance to the flowing liquid flow. Since the compression side discharge passage 5 can be set as a one-way passage, the check valve 17 can be omitted. In this way, in order to set the compression side discharge passage 5 as a one-way passage, the compression side damping valve 15 that allows only the flow of the liquid from one direction may be used, or the compression side damping valve 15 may make the bidirectional flow of the liquid. If the valve is acceptable, the check valve 17 may be used.

One end of the common discharge passage 6 is connected to the other end of the extension side discharge passage 4 and the other end of the compression side discharge passage 5, and the other end is connected to the liquid chamber L of the reservoir R. That is, in the common discharge passage 6, the other end of the extension side discharge passage 4 and the other end of the compression side discharge passage 5 are communicated with the liquid chamber L of the reservoir R. The liquid that has passed from the extension side chamber R1 to the extension side discharge passage 4 goes to the liquid chamber L through the common discharge passage 6 in order to prevent the liquid from flowing from the common discharge passage 6 to the compression side chamber R2. Further, the liquid that has passed through the compression side discharge passage 5 from the compression side chamber R2 is transferred to the liquid chamber L through the common discharge passage 6 because the extension side discharge passage 4 blocks the flow of the liquid from the common discharge passage 6 to the extension side chamber R1. Head. In this way, the liquid passing through the common discharge passage 6 always has one end of the common discharge passage 6 connected to the other end of the extension side discharge passage 4 and the other end of the compression side discharge passage 5 as an upstream, and is a common discharge passage. With the other end of No. 6 as the downstream, the liquid chamber moves toward the L side.

Further, the common discharge passage 6 is provided with a pressure expansion common damping valve 7 that resists the flow of the passing liquid. In the present embodiment, the expansion pressure common damping valve 7 is a variable throttle valve whose opening area can be adjusted by an external operation. The expansion pressure common damping valve 7 changes the resistance given to the flow of the liquid when the opening area is changed.

The extension side suction passage 8 connects the liquid chamber L of the reservoir R and the extension side chamber R1 in the shock absorber D of the present embodiment. Specifically, in the shock absorber D of the present embodiment, the extension side suction passage 8 is configured to include a through hole 1a, an annular gap S, and a conduit 18 leading to an end surface facing the annular gap S of the cap 20. ing. Since it is sufficient that one end of the extension side suction passage 8 is connected to the extension side chamber R1 and the other end is connected to the reservoir R, the specific configuration of the passage can be appropriately changed.

The extension side suction passage 8 is provided with an extension side check valve 8a that allows only the flow of liquid from the reservoir R to the extension side chamber R1. The extension side suction passage 8 is set as a one-way passage that allows only the flow of liquid from the reservoir R to the extension side chamber R1 by installing the extension side check valve 8a.

The compression side suction passage 9 connects the liquid chamber L of the reservoir R and the compression side chamber R2 in the shock absorber D of the present embodiment. Specifically, in the shock absorber D of the present embodiment, the compression side suction passage 9 is formed by a conduit leading to an end surface of the cap 20 facing the compression side chamber R2. Since it is sufficient that one end of the compression side suction passage 9 is connected to the compression side chamber R2 and the other end is connected to the reservoir R, the specific configuration of the passage can be appropriately changed.

The compression side suction passage 9 is provided with a compression side check valve 9a that allows only the flow of liquid from the reservoir R to the compression side chamber R2. The compression side suction passage 9 is set as a one-way passage that allows only the flow of liquid from the reservoir R to the compression side chamber R2 by installing the compression side check valve 9a.

The shock absorber D of the present embodiment is configured as described above, and the operation of the shock absorber D will be described below. First, the operation of the shock absorber D during extension will be described. When the shock absorber D is extended, the piston 3 moves upward in FIG. 1 with respect to the cylinder 1, the extension side chamber R1 is compressed by the piston 3, and the compression side chamber R2 is expanded. The liquid in the extension side chamber R1 to be compressed is blocked by the extension side check valve 8a in the extension side suction passage 8 and by the check valve 17 in the compression side discharge passage 5, so that the extension side discharge passage 4 and the common discharge passage are blocked. It moves to the liquid chamber L of the reservoir R through 6. Since the extension side damping valve 14 and the extension side common damping valve 7 provide resistance to the flow of the liquid passing through the extension side discharge passage 4 and the common discharge passage 6, the pressure in the extension side chamber R1 rises. Further, since the check valve 9a of the compression side suction passage 9 is opened and the liquid is supplied from the reservoir R to the compression side chamber R2 expanded by the movement of the piston 3, the pressure in the compression side chamber R2 is in the reservoir R. It is almost equal to the pressure (reservoir pressure). In this way, there is a difference in pressure between the extension side chamber R1 and the compression side chamber R2, and the shock absorber D generates an extension side damping force that hinders extension by the extension side damping valve 14 and the extension side common damping valve 7. Further, in the present embodiment, the extension side damping force of the shock absorber D can be adjusted in magnitude by adjusting the opening area of the expansion pressure common damping valve 7, which is a variable throttle valve.

Next, the operation of the shock absorber D during contraction will be described. When the shock absorber D contracts, the piston 3 moves downward in FIG. 1 with respect to the cylinder 1, the compression side chamber R2 is compressed by the piston 3, and the extension side chamber R1 is expanded. The liquid in the compressed side chamber R2 is shut off by the compression side check valve 9a in the compression side suction passage 9 and by the check valve 16 in the extension side discharge passage 4, so that the liquid is blocked through the compression side discharge passage 5 and the common discharge passage 6. Move to the liquid chamber L of the reservoir R. Since the compression side damping valve 15 and the expansion pressure common damping valve 7 provide resistance to the flow of the liquid passing through the compression side discharge passage 5 and the common discharge passage 6, the pressure in the compression side chamber R2 rises. Further, since the check valve 8a of the extension side suction passage 8 is opened and the liquid is supplied from the reservoir R to the extension side chamber R1 expanded by the movement of the piston 3, the pressure in the extension side chamber R1 is the reservoir pressure. Almost equal. In this way, there is a difference in pressure between the compression side chamber R2 and the extension side chamber R1, and the shock absorber D generates a compression side damping force that hinders contraction by the compression side damping valve 15 and the extension common damping valve 7. Further, in the present embodiment, the compression side damping force of the shock absorber D can be adjusted in magnitude by adjusting the opening area of the expansion pressure common damping valve 7, which is a variable throttle valve.

In this way, the shock absorber D generates a damping force as it expands and contracts, but at the time of expansion, the liquid flows one-way from the extension side chamber R1 to the liquid chamber L through the extension side damping valve 14 and the extension common damping valve 7. At the same time, the pressure side suction passage 9 flows from the liquid chamber L toward the compression side chamber R2 in one way, and when the liquid contracts, the pressure side damping valve 15 and the expansion common damping valve 7 flow in one way from the compression side chamber R2 to the liquid chamber L. As it flows, it flows one-way through the extension-side suction passage 8 from the liquid chamber L toward the extension-side chamber R1. Further, when the shock absorber D expands and contracts, the liquid always passes through the common discharge passage 6 and the compression common damping valve 7, but the liquid has the common discharge passage 6 as the extension side chamber R1 or the compression side chamber R2 as the upstream and the reservoir R as the downstream. It flows in one way. As described above, in the shock absorber D of the present embodiment, the liquid always flows in the same direction only in the common discharge passage 6 when the shock absorber D is expanded and contracted, and when the shock absorber D is extended, the extension side discharge passage 4 and the compression side suction passage are used. 9 flows in one way, and when the shock absorber D contracts, it flows in one way through the compression side discharge passage 5 and the extension side suction passage 8. Therefore, the liquid does not flow in the same passage in the reverse direction when the shock absorber D is expanded and contracted. Therefore, in the shock absorber D of the present embodiment, unlike the conventional shock absorber, the same passage is not reversed and flows, and various valves (main) provided in each passage 4, 5, 6, 8 and 9. In the case of the embodiment, the problem of closing delay of the extension pressure common damping valve 7 and the check valves 8a, 9a, 16, 17) does not occur, and the shock absorber D can generate a damping force with good responsiveness when the expansion / contraction operation is switched. ..

As described above, the shock absorber D of the present embodiment includes a cylinder 1, a rod 2 movably inserted into the cylinder 1, and a rod 2 connected to the rod 2 and movably inserted into the cylinder 1. A piston 3 that divides the inside of the cylinder 1 into an extension side chamber R1 and a compression side chamber R2, a reservoir R that stores a liquid, and one end connected to the extension side chamber R1 and from the extension side chamber R1 to the other end side. An extension side discharge passage 4 that allows only the flow of liquid toward the end, and a compression side discharge passage 5 that is connected to the compression side chamber R2 and allows only the flow of liquid from the compression side chamber R2 toward the other end, and one end is extended. A common discharge passage 6 connected to the other end of the side discharge passage 4 and the other end of the compression side discharge passage 5 and the other end connected to the reservoir R, and a compression common damping valve 7 provided in the common discharge passage 6. The extension-side suction passage 8 that allows only the flow of liquid from the reservoir R to the extension-side chamber R1 and the compression-side suction passage 9 that allows only the flow of liquid from the reservoir R to the compression-side chamber R2 are provided.

In the shock absorber D configured in this way, as described above, the liquid always flows in the same direction only in the common discharge passage 6 when the shock absorber D expands and contracts, and when the shock absorber D expands, the extension side discharge passage 4 and the compression side suction are sucked. It flows one way through the passage 9, and when the shock absorber D contracts, it flows one way through the compression side discharge passage 5 and the extension side suction passage 8. Therefore, the liquid does not flow in the same passage in the reverse direction when the shock absorber D is expanded and contracted, and the closing delay of the check valves 8a, 9a, 16 and 17 does not occur.

Here, the check valves 8a, 9a, 16 and 17 are, for example, as shown in FIG. 2, a valve case 21 having an annular valve seat 21b surrounding the port 21a and the outlet end of the port 21a, and a valve seat 21b. It is provided with a valve body 22 that takes off and sits on the valve body 22 and a spring 23 that urges the valve body 22 toward the valve seat 21b. In the check valves 8a, 9a, 16 and 17 configured in this way, the liquid flows through the port 21a in one way, so that the diameter of the valve seat 21b can be increased and the lift amount of the valve body 22 from the valve seat 21b can be increased. Can be made smaller. As described above, the shock absorber D of the present embodiment adopts a structure in which the liquid does not flow in the same passage in the reverse direction when the shock absorber D is extended and contracted. Therefore, the check valves 8a, 9a, 16 The time required for closing the valves after opening the valves 17 and 17 can be shortened, and the delay in closing the check valves 8a, 9a, 16 and 17 can be suppressed. Therefore, according to the shock absorber D of the present embodiment, it is possible to prevent the check valves 8a, 9a, 16 and 17 from being delayed in closing when the shock absorber D is switched between expansion and contraction, so that the responsiveness to the generation of damping force can be improved.

In addition, the action effect of the shock absorber D that the damping force can be generated with good responsiveness when the expansion / contraction operation is switched is that the extension side discharge passage 4 allows only the flow of the liquid from the extension side chamber R1 to the common discharge passage 6 in the opposite direction. It is set as a one-way passage that blocks the flow of liquid, and the compression side discharge passage 5 is set as a one-way passage that allows only the flow of liquid from the compression side chamber R2 to the common discharge passage 6 and blocks the reverse flow. Therefore, one or both of the extension side damping valve 14 provided in the extension side discharge passage 4 and the compression side damping valve 15 provided in the compression side discharge passage 5 may be abolished. Further, regarding the extension side chamber R1 side from the check valve 16 and the extension side damping valve 14 in the extension side discharge passage 4, and the extension side chamber R1 side from the check valve 8a of the extension side suction passage 8, the extension side discharge passage 4 and the extension side suction passage 4 The passage may be shared with the passage 8. Further, on the compression side chamber R2 side from the check valve 17 and the compression side damping valve 15 in the compression side discharge passage 5, and the compression side chamber R2 side from the check valve 9a of the compression side suction passage 9, the compression side discharge passage 5 and the compression side suction passage 9 pass through the passage. May be common. Even in this case, since the liquid passes through various valves provided in the passages 4, 5, 6, 8 and 9 in one way, the effect of the present invention is not lost.

Further, the shock absorber D of the present embodiment includes an extension side damping valve 14 provided in the extension side discharge passage 4 and a compression side damping valve 15 provided in the compression side discharge passage 5. In the shock absorber D configured in this way, the extension side damping force is generated by the extension side damping valve 14 and the extension common damping valve 7 at the time of extension, and the compression side damping valve 15 and the extension common damping valve 7 generate the extension side damping force at the time of contraction. Since the compression side damping force is generated, the extension side damping force and the compression side damping force can be set independently.

Further, in the shock absorber D of the present embodiment, the extension side damping valve 14 provided in the extension side discharge passage 4 and the compression side damping valve 15 provided in the compression side discharge passage 5 are variable throttle valves. By adjusting the resistance given to the flow of the liquid by the side damping valve 14 and the compression side damping valve 15, the damping force on the extension side and the compression side of the shock absorber D can be independently adjusted in magnitude. Therefore, according to the shock absorber D configured as described above, the damping forces on the extension side and the compression side can be independently adjusted so as to be suitable for suppressing the vibration of the vehicle body of the applied vehicle. In the above-mentioned place, the extension side damping valve 14 and the compression side damping valve 15 are variable throttle valves, but any variable damping valve capable of adjusting the resistance given to the flow of the liquid may be used. In addition to the variable throttle valve whose area can be adjusted, a variable relief valve whose valve opening pressure can be adjusted may be used.

Further, since the compression common damping valve 7 in the shock absorber D of the present embodiment is a variable throttle valve, the compression common damping valve 7 applies the damping force on the extension side and the compression side of the shock absorber D to flow the liquid. The size can be adjusted by adjusting the resistance given to. Therefore, according to the shock absorber D configured in this way, the damping force on the extension side and the damping force on the compression side can be adjusted at the same time so as to be suitable for suppressing the vibration of the vehicle body of the applied vehicle. In the above-mentioned place, the expansion pressure common damping valve 7 is a variable throttle valve, but since it is sufficient if it is a variable damping valve capable of adjusting the resistance given to the flow of liquid, the flow path area can be adjusted. In addition to the variable throttle valve that can be used, a variable relief valve that can adjust the valve opening pressure may be used.

Further, as in the shock absorber D1 of the first modification of the first embodiment shown in FIG. 3, in addition to the configuration of the shock absorber D, the extension side discharge passage is connected to the common discharge passage 6 in series with the expansion common damping valve 7. A common check valve 25 may be provided that allows only the flow of liquid from the 4 and the compression side discharge passage 5 toward the liquid chamber L in the reservoir R. As described above, in the shock absorber D1 provided with the common check valve 25 in the common discharge passage 6, it is possible to prevent the liquid from flowing back from the liquid chamber L to the extension side discharge passage 4 or the compression side discharge passage 5. When the gas is dissolved in the liquid or the liquid entrains the gas, the liquid apparently exhibits elasticity, and when the expansion / contraction of the shock absorber D1 is switched, the compression side from the extension side damping valve 14 of the extension side discharge passage 4 There is a possibility that the liquid is compressed between the pressure side damping valve 15 of the discharge passage 5 and the common discharge passage 6, and the liquid flows back from the liquid chamber L to the common discharge passage 6. When the liquid flows back from the liquid chamber L to the common discharge passage 6 in this way, the flow rate of the liquid passing through the expansion common damping valve 7 and the expansion side damping valve 14 and the compression side damping valve 15 at the switching of expansion and contraction of the shock absorber D1. If is provided, the flow rate of the liquid passing through them may not be stable and the damping force may fluctuate sharply. Therefore, when the common check valve 25 is provided as in the shock absorber D1 of the present embodiment, it is possible to prevent the backflow of the liquid from the liquid chamber L to the common discharge passage 6 side. Therefore, according to the shock absorber D1 of the first modification of the first embodiment, it is possible to prevent the disturbance of the damping force and further improve the riding comfort in the vehicle.

Further, as in the shock absorber D2 of the second modification of the second embodiment shown in FIG. 4, in addition to the configuration of the shock absorber D, the relief valve 26 is parallel to the compression common damping valve 7 in the common discharge passage 6. May be provided. As shown in FIG. 5, the damping force characteristic of the shock absorber D2 configured as described above (characteristic of the damping force generated by the shock absorber D2 with respect to the piston speed, which is the speed of the piston 3 with respect to the cylinder 1) is the relief valve 26. Since the liquid passes through the expansion common damping valve 7 until the valve is opened, the characteristics of the expansion common damping valve 7 appear, and after the relief valve 26 is opened, the characteristics of the extension side damping valve 14 and the compression side damping valve 15 are mainly exhibited. It will appear. Therefore, in the shock absorber D2 configured in this way, the damping when the piston speed (expansion / contraction speed of the shock absorber D2) when the piston 3 moves with respect to the cylinder 1 in the compression common damping valve 7 is in the low speed range. The force characteristic can be set, and the damping force characteristic can be set when the piston speed is in the high speed range exceeding the low speed range in the extension side damping valve 14 and the compression side damping valve 15. Further, when the extension pressure common damping valve 7, the extension side damping valve 14 and the compression side damping valve 15 are variable damping valves, the extension side and compression side damping force characteristics when the piston speed of the shock absorber D2 is in the low speed range. Can be adjusted by the extension pressure common damping valve 7, and the extension side and compression side damping force characteristics when the piston speed of the shock absorber D2 is in the high speed range can be adjusted independently by extension side damping valve 14 and compression side damping valve 15. can. The extension side damping valve 14 and the compression side damping valve 15 may be not a throttle valve or a variable throttle valve but a damping valve having a check function.

Although the preferred embodiments of the present invention have been described in detail above, they can be modified, modified, and modified as long as they do not deviate from the claims.

1 ... Cylinder, 2 ... Rod, 3 ... Piston, 4 ... Extension side discharge passage, 5 ... Compression side discharge passage, 6 ... Common discharge passage, 7 ... Common extension Damping valve, 8 ... extension side suction passage, 9 ... compression side suction passage, 14 ... extension side damping valve, 15 ... compression side damping valve, 25 ... common check valve, 26 ... relief Valve, D, D1, D2 ... shock absorber, R ... reservoir, R1 ... extension side chamber, R2 ... compression side chamber

Claims (5)

Cylinder and
A rod that is movably inserted into the cylinder,
A piston that is connected to the rod and is movably inserted into the cylinder and divides the inside of the cylinder into an extension side chamber and a compression side chamber filled with a liquid.
A reservoir that stores liquid and
An extension side discharge passage whose one end is connected to the extension side chamber and which allows only the flow of liquid from the extension side chamber toward the other end side.
A compression side discharge passage that is connected to the compression side chamber at one end and allows only the flow of liquid from the compression side chamber toward the other end.
A common discharge passage in which one end is connected to the other end of the extension side discharge passage and the other end of the compression side discharge passage and the other end is connected to the reservoir.
The extension pressure common damping valve provided in the common discharge passage and
An extension-side suction passage that allows only the flow of liquid from the reservoir to the extension-side chamber,
A shock absorber comprising a compression side suction passage that allows only the flow of liquid from the reservoir to the compression side chamber. The shock absorber according to claim 1, further comprising a common check valve provided in the common discharge passage and allowing only a liquid flow from the one end of the common discharge passage toward the reservoir side. The extension side damping valve provided in the extension side discharge passage and
The shock absorber according to claim 1 or 2, further comprising a pressure side damping valve provided in the pressure side discharge passage. The shock absorber according to claim 3, wherein the common discharge passage is provided with a relief valve arranged in parallel with the extension pressure common damping valve. The shock absorber according to any one of claims 1 to 4, wherein the extension pressure common damping valve is a variable damping valve.

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