JPH078643U - Shock absorber - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a shock absorber capable of improving the vehicle performance by reducing the damping force characteristic when the piston speed decreases after the maximum piston speed is reached. A first extension provided on an end surface of the main piston valve 4 on the side of the intermediate chamber 11 that restricts the fluid flow from the upper chamber A toward the intermediate chamber 11 during the extension stroke to generate a damping force. A second disc valve 5 and an end face of the sub-piston valve 7 on the side of the second chamber, which generates a damping force by restricting the flow of fluid from the intermediate chamber to the lower chamber B in the extension stroke. 2 Expansion side disk valve 8
And a bypass flow passage that bypasses the second expansion-side disk valve to connect the intermediate chamber and the lower chamber, and the rising hydraulic pressure on the lower chamber side is received in the pressure receiving chamber C to displace the bypass flow passage in the closing direction. Then, the seat valve 1 which is displaced in the direction of opening the bypass passage by the displacement caused by the opening of the first extension side disc valve
2 and an on-off valve device composed of the on-off valve 14.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a shock absorber suitable for use in a vehicle suspension.

[0002]

[Prior art]

 As a conventional shock absorber, for example, a shock absorber disclosed in JP-A-61-109933 is known.

In this conventional shock absorber, the damping force generating means for generating a damping force by restricting the flow of hydraulic fluid between the chambers defined by the piston is a disc valve with a fixed inner circumference. As shown by the solid line in FIG. 4, the damping force is generated with a sine waveform that maximizes when the maximum piston speed is reached in each extension / compression stroke.

[0004]

[Problems to be solved by the device]

 However, such a conventional shock absorber has the following problems.

That is, in the vehicle, although the input energy is gradually attenuated by the damping force generated by the shock absorber with respect to one input, the damping force generated by the shock absorber is the maximum piston speed in each extension and compression stroke. Since the sine waveform maximizes the arrival time, an excessive damping force state occurs and the riding comfort and steering stability of the vehicle are deteriorated.

The present invention has been made by paying attention to the above-mentioned conventional problems, and improves the vehicle performance by reducing the damping force characteristic when the piston speed decreases after the maximum piston speed is reached. An object of the present invention is to provide a shock absorber that can be used.

[0007]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the shock absorber of the present invention has a main valve body that defines the inside of a cylinder into a first chamber and a second chamber, and a main valve body provided on one side of the main valve body. A sub-valve body that forms an intermediate chamber between the valve body and the intermediate chamber side end surface of the main valve body, and restricts the flow of fluid from the first chamber to the intermediate chamber during the stroke of the shock absorber. The first disc valve that generates a damping force by allowing it and the second chamber side end face of the sub-valve body restrict the flow of fluid from the intermediate chamber to the second chamber during the stroke of the shock absorber. Is formed in the sub-valve body, and the second disc valve that generates a damping force by allowing the second disc valve to bypass, and the bypass passage that allows only the flow from the intermediate chamber to the second chamber by bypassing the second disc valve. It is slidably fitted in the annular recess, and forms a pressure receiving chamber with the bottom of the annular recess, and receives the rising hydraulic pressure on the side of the second chamber to close the bypass passage. A means provided with an opening / closing valve device that is displaced and is displaced in the direction in which the bypass flow passage is opened by the displacement due to the opening of the first disc valve, and an orifice that connects the pressure receiving chamber and the second chamber.

[0008]

[Action]

 Since the shock absorber of the present invention is configured as described above, during the stroke of the shock absorber in which the hydraulic pressure on the second chamber side rises, the rising hydraulic pressure on the second chamber side is received through the orifice in the pressure receiving chamber. By receiving the pressure at, the on-off valve device is displaced in the direction to close the bypass passage.

Therefore, when switching from this state to the stroke side of the shock absorber in which the hydraulic pressure on the first chamber side rises, the hydraulic fluid in the first chamber opens the first disc valve to the intermediate chamber. Inflow. At this time, the opening / closing valve device is displaced in the opening direction of the bypass passage due to the displacement caused by the opening of the first disc valve, but the bypass passage is displaced while the first disc valve is displaced in the opening direction. Is kept closed. Therefore, until the maximum piston speed at which the opening (displacement amount) of the first disc valve reaches the maximum, the hydraulic fluid that has flowed into the intermediate chamber opens the second disc valve to open the second disc valve. In addition to flowing into the chamber side, the opening (displacement amount) of the first disc valve gradually decreases after the maximum piston speed is reached, so only the amount by which the opening / closing valve device is displaced in the direction to open the bypass passage is bypassed. The flow path is opened, and as a result, a flow that flows from the intermediate chamber to the second chamber side via the bypass flow path is generated. Therefore, compared with the case where the second disc valve is opened and communication is performed. The damping force decreases.

Therefore, the damping force characteristic when the piston speed decreases after the maximum piston speed is reached is reduced, and the vehicle performance is improved.

[0011]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the configuration of the embodiment will be described.

FIG. 1 is a cross-sectional view showing a structure of a piston P portion in a shock absorber according to an embodiment of the present invention. As shown in FIG. 1, the piston P has an upper chamber (first chamber) inside a cylinder 1. ) A and a lower chamber (second chamber) B are defined so as to be slidable, and the piston P is attached to the tip small diameter portion 3 a of the piston rod 3.

That is, the main piston valve (main valve body) 4, the first expansion side disc valve 5, the spacer 6, and the sub piston valve (sub valve body) 7 are attached to the small diameter portion 3 a of the piston rod 3. Then, the second expansion side disc valve 8 and the expansion side check valve 9 are sequentially mounted, and finally fastened with the nut 10.

An intermediate chamber 11 is formed between the main piston valve 4 and the sub piston valve 7.

An annular groove 4b is formed on the lower end surface side of the main piston valve 4 and communicates with the upper chamber A through an extension side communication hole 4a. The annular groove 4b is closed in the first groove 4b. The expansion side disc valve 5 is provided. A pressure side communication groove 4c that communicates between the intermediate chamber 11 and the upper chamber A is formed outside the annular groove 4b in the main piston valve 4.

As shown in detail in FIG. 2, an inner annular groove 7b communicating with the intermediate chamber 11 via an inner communication hole 7a and an outer communication hole 7c are formed on the lower end surface side of the sub-piston valve 7. There are formed four outer circumferential recesses 7d which communicate with the intermediate chamber 11 via the circumferential direction, and the second extension side disc valve 8 is closed while the inner annular groove 7b and the outer recess 7d are closed. It is provided. On the inner peripheral side of the second disc valve 8, as shown in detail in FIG. 3, a slit-shaped orifice hole 8a which connects the inner annular groove 7b and the lower chamber B is formed. In addition, the extension side check valve 9 is provided in a state where the orifice hole 8a is closed from the lower chamber B side.

Inside the intermediate chamber 11, there is provided a seat valve 12 which is movable up and down in the axial direction along the outer peripheral surface of the spacer 6. The seat valve 12 is in a state in which the annular protrusion 12a formed on the upper surface of the seat valve 12 by the biasing force of the spring 13 is always in contact with the lower end of the first extension-side disk valve 5. .

On the upper end surface side of the sub-piston valve 7, a ring-shaped recess 7e is formed at a position between both communication holes 7a, 7c, and the lower portion of the cylindrical opening / closing valve 14 is located inside the ring-shaped recess 7e. The on-off valve 14 forms a pressure receiving chamber C at the bottom of the annular recess 7e. O-rings 15 and 15 that seal between the inner and outer sliding surfaces of the annular recess 7e are mounted on the inner and outer peripheral surfaces of the on-off valve 14. Further, an orifice hole 7f communicating with the lower chamber B is formed at the bottom of the pressure receiving chamber C, and the hydraulic pressure of the lower chamber B is received by the pressure receiving chamber C through the orifice hole 7f, so that the opening / closing valve 14 The upper end surface of the on-off valve 14 abuts the lower surface of the seat valve 12 so that the intermediate chamber 11 and the inner annular groove 7b can be shut off from each other. That is, in this embodiment, the on-off valve device is constituted by the seat valve 12, the spring 13 and the on-off valve 14.

An annular groove 7h communicating with the lower chamber B via a pressure side communication hole 7g is formed on the outer peripheral side upper surface of the sub-piston valve 7, and the annular pressure side check is performed in a state where the annular groove 7h is closed. A valve 16 is provided. A spring 17 is interposed between the pressure side check valve 16 and the seat valve 12 to bias the pressure side check valve 16 in the direction of closing the annular groove 7h.

Next, the operation of the embodiment will be described. (A) During the pressure stroke of the shock absorber (see the right half cross-sectional view in FIG. 1) In the pressure stroke of the shock absorber in which the piston P slides downward with respect to the cylinder 1, the hydraulic fluid on the side of the compressed lower chamber B is compressed. Through the pressure side communication hole 7g of the sub-piston valve 7 and the annular groove 7h, the pressure side check valve 16 is opened and flows into the intermediate chamber 11, and from this intermediate chamber 11 the pressure side communication hole of the main piston valve 4. 4c, the pressure side disc valve (not shown) is opened and flows into the upper chamber A side. As a result, as shown in FIG. 4, the sine waveform is attenuated when the maximum piston speed is reached. Force characteristic is generated.

At this time, since the hydraulic fluid pressure on the lower chamber B side is supplied into the pressure receiving chamber C via the orifice hole 7f, the on-off valve 14 is pushed upward and slid. The upper end surface of the on-off valve 14 abuts the lower surface of the seat valve 12, whereby a bypass flow path connecting the intermediate chamber 11, the inner communication hole 7a, the inner annular groove 7b, and the orifice hole 8a is formed. It has been cut off.

(B) During the stroke of the shock absorber (see the left half sectional view of FIG. 1) In the stroke of the shock absorber in which the piston P slides upward with respect to the cylinder 1, the side of the compressed upper chamber A The hydraulic fluid of 1 opens the first extension side disc valve 5 and flows into the intermediate chamber 11. At this time, the seat valve 12 is pressed and slid downward against the urging force of the spring 13 due to the downward displacement of the outer peripheral side due to the opening of the first expansion-side disc valve 5. The on-off valve 14 is also pressed and slid downward toward the inside of the annular recess 7e. The hydraulic fluid that has flowed into the intermediate chamber 11 passes through the outer communication hole 7c and the outer recess 7d of the sub-piston valve 7 and opens the second extension side disc valve 8 to flow into the lower chamber B side. As a result, as shown in Fig. 4, until the maximum piston speed is reached, a damping force characteristic of a sine waveform having the maximum value at that point is generated.

Next, after the maximum piston speed is reached, when the piston speed begins to decrease, the opening degree of the first extension side disc valve 5 decreases, that is, the outer peripheral side of the first extension side disc valve 5 moves upward. As the seat valve 12 is pushed back by the urging force of the spring 13 by the movement, and the opening / closing valve 14 is held in that position by the throttling action of the orifice hole 7f, the upper end surface of the opening / closing valve 14 A gap a is formed between the lower surface of the seat valve 12 and the lower surface of the seat valve 12, whereby the hydraulic fluid on the side of the upper chamber A that has flowed into the intermediate chamber 11 passes through the gap a and the inside of the on-off valve 14. Flow through the bypass passage passing through the inner communication hole 7a of the sub-piston valve 7, the inner annular groove 7b and the orifice hole 8a of the second expansion side disc valve 8 from that position, and then the expansion side check valve The valve opens the valve 9 and flows into the lower chamber B side. As a result, after reaching the maximum piston speed, the damping force characteristic of the sine waveform shown by the solid line in FIG. The damping force characteristic can be reduced.

As described above, the damping force variable shock absorber of this embodiment can improve the vehicle performance by reducing the damping force characteristics when the piston speed decreases after the maximum piston speed is reached. It has the feature that

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and there are design changes and the like within a range not departing from the gist of the present invention. Even included in the present invention.

For example, in the embodiment, the example in which the present invention is applied to the piston as the valve body is shown, but the invention can also be applied to the base valve and the like.

Further, in the embodiment, the present invention is applied to the extension stroke side, but it may be applied to the pressure stroke side or both the extension stroke and the compression stroke side.

Further, in the embodiment, the on-off valve device is constituted by the on-off valve and the seat valve, but the seat valve is omitted and the tip end surface of the on-off valve is brought into contact with the first extension side disc valve. Also, the same effect can be obtained.

[0029]

[Effect of device]

 As described above, in the shock absorber of the present invention, the bypass passage for bypassing the second disk valve to allow only the flow in the direction from the intermediate chamber to the second chamber, and the rising hydraulic pressure on the second chamber side. The maximum piston speed is provided by providing an on-off valve device that displaces the bypass flow passage in the closing direction by receiving pressure in the pressure receiving chamber, and displaces the bypass flow passage in the opening direction by the displacement caused by opening the first disc valve. It is possible to improve the vehicle performance by reducing the damping force characteristic when the piston speed decreases after the vehicle arrives.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing a main part of a shock absorber according to an embodiment of the present invention.

FIG. 2 is a bottom view showing a sub-piston valve portion of the shock absorber of the embodiment.

FIG. 3 is a plan view showing a second expansion side disc valve in the shock absorber of the embodiment.

FIG. 4 is a damping force characteristic diagram of the shock absorber of the embodiment.

[Explanation of symbols]

 A Upper chamber (first chamber) B Lower chamber (second chamber) C Pressure receiving chamber 1 Cylinder 4 Main piston valve (main valve body) 5 First expansion side disc valve 7 Sub piston valve (sub valve body) 7e Annular recess 7f Orifice hole (orifice) 8 Second expansion side disc valve 11 Intermediate chamber 12 Seat valve (open / close valve device) 14 Open / close valve (open / close valve device)

Claims (1)

[Scope of utility model registration request] 1. A main valve body which defines a first chamber and a second chamber in a cylinder, and a sub valve which is provided on one side of the main valve body and forms an intermediate chamber between the main valve body and the main valve body. A first body, which is provided on an end surface of the main valve body on the side of the intermediate chamber, generates a damping force by restricting the fluid flow from the first chamber toward the intermediate chamber during the stroke of the shock absorber.
The disc valve and the second valve-side second end of the sub-valve body that generates damping force by restricting the flow of fluid from the intermediate chamber to the second chamber during the stroke of the shock absorber A disc valve, a bypass flow passage that bypasses the second disc valve and allows only a flow in the direction from the intermediate chamber to the second chamber, and is slidably fitted in an annular recess formed in the sub-valve body. A pressure receiving chamber is formed between the bottom of the concave portion and the rising hydraulic pressure on the second chamber side is received to displace the bypass passage in the direction of closing the bypass passage, and the displacement of the bypass valve due to the opening of the first disc valve opens the bypass passage. A shock absorber, comprising: an opening / closing valve device that is displaced in the opening direction; and an orifice that connects the pressure receiving chamber and the second chamber.