WO2013122250A1

WO2013122250A1 - Damping force control valve and shock absorber

Info

Publication number: WO2013122250A1
Application number: PCT/JP2013/053844
Authority: WO
Inventors: 福田　博美
Original assignee: ヤマハ発動機株式会社
Priority date: 2012-02-17
Filing date: 2013-02-18
Publication date: 2013-08-22
Also published as: JP2013170600A

Abstract

Provided is a damping force control valve having excellent valve body position control characteristics during minute opening thereof. The damping force control valve (10) comprises: a hollow, cylindrical valve body (20) reciprocally moved by a solenoid (23); a first working fluid chamber (30) comprising a port (30a); and a second working fluid chamber (40) connected to a passage (21). A gap between an end surface (20a) of the valve body (20) and the port (30a) is a flowpath through which the working fluid passes, and the damping force is controlled by the degree of opening of the flowpath. A large diameter section (21a) of the passage (21), in the end surface of the valve body (20), has an opening area that is larger than a connecting section (21b), thereby making it difficult for eddies to be generated inside the large diameter section (21a). As a result, pressure reduction on the surface of the end surface (20a) is prevented when the working fluid is discharged from the first working fluid chamber (30) through the port (30a).

Description

Damping force control valve and shock absorber

The present invention relates to a damping force control valve and a shock absorber.

In general, a motor vehicle, a motorcycle and the like are provided with a shock absorber (shock absorber) in order to attenuate vibrations generated in the vehicle. The shock absorber usually comprises a cylinder, in which a piston and a support shaft for supporting the piston are provided. The inside of the cylinder is separated into two oil chambers by the piston, and the piston moves according to the expansion and contraction of the shock absorber, whereby the oil moves between the two oil chambers. The oil movement path is provided with an orifice, valve, etc. with a relatively narrow flow path area, and the fluid resistance when passing through these narrow flow paths generates a damping force and is generated in the vehicle Damping vibration.

As a conventional shock absorber, there is a shock absorber provided with a damping force control valve (variable orifice) whose opening degree can be adjusted by electronic control. As such shock absorbers, there are a shock absorber in which the valve is installed in the cylinder and a shock absorber in which the valve is installed outside the cylinder. In either case, the valve depends on the traveling conditions. The damping force can be controlled by adjusting the opening degree of.

As a conventional damping force control valve, there is, for example, a damping force control valve provided with a stepping motor. In such a damping force control valve, the position of the valve body is adjusted by the stepping motor to change the opening degree of the valve. Therefore, it is hard to produce the position change of the valve body by hydraulic force, and position control of a valve body can be performed comparatively correctly. On the other hand, in the stepping motor, the rotational angle changes due to the integration of the pulses, and the linear velocity of the valve is determined by the pitch of the screw that converts the rotational movement into the linear movement. Since it is necessary to stop the valve body against oil pressure, the pitch of the screw can not be increased. Therefore, it takes a relatively long time to move the valve body to the target position. As a result, there is a problem that excellent responsiveness can not be obtained.

An advantage of damping force control by electronic control is that damping force can be adjusted according to driving conditions, but as described above, if excellent responsiveness can not be obtained, damping force can be accurate according to driving conditions. It is difficult to adjust well, and the merit of damping control by electronic control can not be fully utilized.

Further, as a conventional damping force control valve, there is a damping force control valve provided with a solenoid (see, for example, Patent Document 1). In the damping force control valve shown in Patent Document 1, as shown in FIG. 8 (see FIG. 6 of Patent Document 1), a hollow cylindrical valve body 200 linearly reciprocated by a solenoid is formed in the first working fluid chamber 234 The guide holes 234c are inserted. The first working fluid chamber 234 is in communication with a second working fluid chamber (not shown) via the passage 200 e of the valve body 200. The second working fluid chamber corresponds to the oil chamber 112 in Patent Document 1. Further, a port 234 b is provided in the first working fluid chamber 234 at a position facing the end face 200 c of the valve body 200. A gap between the end face 200c of the valve body 200 and the port 234b is a flow path of the working fluid. The opening degree of the flow path is changed by the position of the end face 200c of the valve body 200, whereby the damping force is controlled. According to such a damping force control valve, since the position of the valve body 200 is adjusted by the solenoid, the valve body 200 can be quickly moved to the target position, and excellent responsiveness can be obtained. Therefore, according to the damping force control valve shown in Patent Document 1, it is possible to solve the problem that excellent responsiveness can not be obtained when a stepping motor is used.

International Publication No. 2011/078317 brochure

However, in the shock absorber using the damping force control valve shown in Patent Document 1, as shown in FIG. 8, when the flow path of the working fluid (the gap between the end face of the valve body and the opening) has a minute opening degree The valve body 200 may not be stable at the target position. Therefore, the damping force control valve shown in Patent Document 1 has room for improvement in the position controllability of the valve body 200 at the minute opening degree.

An object of the present invention is to provide a damping force control valve which is excellent in position controllability of a valve body at the time of a minute opening degree, and which has a wide range of an opening degree which can be accurately controlled.

The inventors examined the above-mentioned problems and obtained the following findings.
As shown in FIG. 8, when the distance between the end face 200 c of the valve body 200 and the port 234 b (flow path of the working fluid) is narrow, a force is applied to the vehicle to extend and retract the suspension, and the working fluid is the first working fluid chamber 234. When the air is discharged from the first working fluid chamber 234 through the above-mentioned interval, the flow S of working fluid becomes faster because the above-mentioned interval is narrow.

The flow S of the working fluid passes between the periphery of the end face 200 c of the valve body 200 and the periphery of the port 234 b and enters the working fluid passage 232. The flow S of the working fluid at this time goes from the outer peripheral side to the central side of the valve body 200 while going downstream along the axial direction of the valve body 200. Therefore, the flows S of the working fluid from the entire periphery collide with each other. As a result, a flow F of the working fluid directed downstream and a flow R directed in the opposite direction to the flow F are generated.

The flow F of the working fluid passes through the working fluid passage 232 and becomes a rapid flow going out of the damping passage control valve. Therefore, the pressure in the working fluid passage 232 is lowered. In addition, the generation of the flow R of the working fluid raises the pressure in the passage 200e, and the pressure is propagated to the second working fluid chamber (corresponding to the second working fluid chamber 40 in Patent Document 1). The pressure in the working fluid chamber increases. The flow of the working fluid F, R causes a pressure difference between the passage 200 e and the working fluid passage 232. The pressure difference applies a force to the valve body 200 toward the port 234 b.

Further, the narrower the distance between the end face 200c of the valve body 200 and the port 234b (the flow path of the working fluid), the faster the flow S of the working fluid, so the working fluid on the surface of the end face 200c of the valve body 200 It is drawn to the fluid flow S. Therefore, the pressure on the surface of the end face 200c of the valve body 200 becomes low, and as a result, a force toward the port 234b is applied to the valve body 200.

Thus, when the valve body 200 is subjected to a force toward the port 234b, the valve body 200 approaches the port 234b, and the distance between the end face 200c of the valve body 200 and the port 234b (flow path of working fluid) becomes narrower. . The smaller the distance between the end face 200c of the valve body 200 and the port 234b, the stronger the force applied to the valve body 200, and therefore the position of the valve body 200 is further changed.
Such a mechanism causes the case where the valve body 200 is not stable at the target position.

The problems described above do not occur in a damping force control valve provided with a stepping motor. This is because, when adjusting the position of the valve body by the stepping motor, the valve body does not move even when receiving a fluid force, so the position of the valve body does not change due to the flow of the working fluid.
The above finding is a generation mechanism of a problem unique to a damping force control valve provided with a solenoid, and the present inventors obtained the above finding and completed the present invention based on the above finding.

That is, the present invention adopts the following configuration.
(1) Damping force control valve
The damping force control valve is
A hollow cylindrical valve body linearly reciprocated by a solenoid;
A first working fluid chamber including a guide hole through which the valve body is inserted, and a port formed at a position facing the end face of the valve body;
A second working fluid chamber in communication with the first working fluid chamber via a passage in the valve body;
Equipped with
A gap between the end face of the valve body and the port is a flow passage through which the working fluid passes,
The opening degree of the flow passage is changed by the position of the end face of the valve body, whereby the damping force is controlled,
When the opening degree of the flow path is minimum, the gap between the valve body and the port is fully closed, and when the opening degree of the flow path is maximum, the valve body is separated from the port;
In the passage in the valve body, the opening area of the downstream end of the flow direction in which the working fluid in the first working fluid chamber is discharged out of the first working fluid chamber through the port is the largest opening in the passage. Larger than the opening area of the small diameter portion.

According to the configuration of (1), the opening area of the downstream end is larger than the opening area of the smallest diameter portion in the passage. As a result, on the downstream side of the passage, a space having a larger opening area than the minimum diameter portion is secured. Therefore, even if a flow R (see FIG. 8) of the working fluid from the downstream side to the second working fluid chamber via the passage occurs, the flow R of the working fluid is a space having a large open area downstream of the minimum diameter portion It is easy to return to the flow F of the working fluid while diffusing in a vortex. As a result, since it is possible to suppress an increase in pressure in the second working fluid chamber, it is possible to prevent an increase in the pressure difference between the downstream side and the inside of the passage, and to suppress the force applied to the valve toward the port. .

In addition, since the opening area of the downstream end is large, the distance S along which the flow S (see FIG. 8) of working fluid passing between the end face of the valve body and the port flows along the surface of the end face of the valve body Relatively short. Therefore, the working fluid on the surface of the end face of the valve body is less likely to be attracted to the flow S of the working fluid. Therefore, the pressure drop on the surface of the end face of the valve disc can be prevented, and the force applied to the valve disc toward the port can be suppressed. Therefore, according to the configuration of (1), the position controllability of the valve body at the time of the minute opening degree is excellent, and the range of the opening degree that can be accurately controlled is wide, and high responsiveness can be realized.

(2) The damping force control valve of (1),
The damping force control valve includes an annular biasing body through which the valve body is inserted in the first working fluid chamber and which applies a force to the valve body along an axial direction of the valve body.
In the passage in the valve body, the opening area of the downstream end is preferably smaller than the inner diameter area of the biasing body.

According to the configuration of (2), the opening area of the downstream end is smaller than the inner diameter area of the annular biasing body that applies a force to the valve body along the axial direction of the valve body, and the biasing body Since it is inserted, it is not necessary to install the biasing body in the passage from the first working fluid chamber to the second working fluid chamber via the passage. Therefore, the pressure transmission or the movement of the working fluid in the passage at the time of the movement of the valve body is smooth, and the responsiveness can be further improved.

(3) The damping force control valve according to (1) or (2), wherein
The passage has a large diameter portion including the downstream end, and the diameter of the large diameter portion extends from the opposite end of the downstream end of the large diameter portion toward the second working fluid chamber Preferably, it is larger than the diameter of the part.

According to the configuration of (3), in the large diameter portion having a diameter larger than the diameter of the communication portion, the flow R of the working fluid is likely to return to the flow F of the working fluid while forming a vortex and diffusing. In addition, the flow S of the working fluid passing between the end face of the valve body and the port (see FIG. 8) flows along the surface of the end face of the valve body so as to reduce the force applied to the valve body toward the port. can do. Therefore, according to the configuration of (3), the position controllability of the valve body at the time of the minute opening can be further improved, and the range of the opening that can be accurately controlled can be wider and higher response can be realized.

(4) The damping force control valve of (3),
It is preferable that the large diameter portion has a step in which the diameter of the passage changes.

According to the configuration of (4), since the vortices are easily generated in the large diameter portion, an increase in the pressure of the second working fluid chamber can be effectively suppressed.

(5) The damping force control valve according to (3) or (4), wherein
The large diameter portion preferably has a tapered shape in which the diameter of the passage increases as it approaches the downstream end.

According to the configuration of (5), since the vortices are easily generated in the large diameter portion, the increase in the pressure of the second working fluid chamber can be effectively suppressed.

(6) The damping force control valve according to any one of (3) to (5), wherein
It is preferable that the gravity center position of the large diameter portion and the gravity center position of the valve body be different in the axial direction of the valve body.

When the position of the center of gravity of the large diameter portion matches the position of the center of gravity of the valve body, it is difficult to stabilize the valve body on the axis because there is a minute gap between the valve body and the bearing. Therefore, the flow of the working fluid may fluctuate, and as a result, the flow may become unstable.
On the other hand, according to the configuration of (6), by making the position of the center of gravity of the large diameter portion and the position of the center of gravity of the valve body different, temporal fluctuation of the working fluid flow is suppressed and the working fluid flow is reduced. It can be stabilized. As a result, the radial position of the valve body is stabilized, and fluctuations in fluid force can be suppressed. As a result, stability and accuracy of position control of the valve body in the axial direction can be improved.

(7) The damping force control valve according to any one of (1) to (6), wherein
Preferably, substantially only fluid is present in the passage of the valve body.
In addition, "fluid" here is not limited to a working fluid, but contains gas, such as air. Also, "substantially only the fluid is present" means that the fluid may contain solid impurities moving with the working fluid. Such solid impurities include, for example, dust generated from the sliding portion in the valve (or shock absorber).

According to the configuration of (7), no urging body or the like is attached in the passage, and the movement of the working fluid in the passage is smooth at the time of movement of the valve body, and the response can be further improved. .

(8) The damping force control valve according to any one of (1) to (7), wherein
It is preferable that the flow direction in which the working fluid in the first working fluid chamber is discharged to the outside of the first working fluid chamber through the port is along the axial direction of the valve body.

According to the configuration of (8), since the working fluid can be smoothly discharged to the outside of the first working fluid, the responsiveness can be further improved.

(9) It is a shock absorber,
The shock absorber preferably includes a damping force control valve according to any one of (1) to (8).

According to the configuration of (9), since the damping force control valve of any one of (1) to (8) is provided, the range of damping force that can be accurately controlled is wide, and high responsiveness can be realized.

(10) The shock absorber of (9),
The shock absorber is configured to flow the working fluid in a direction in which the working fluid in the first working fluid chamber is discharged to the outside of the first working fluid via the port in the damping force control valve. Is preferred.

According to the configuration of (10), in the damping force control valve, the working fluid can be made to flow in the direction in which the force applied to the valve body toward the port can be more effectively suppressed. Therefore, the range of damping force that can be accurately controlled is wider, and higher responsiveness can be realized.

The above and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention taken in conjunction with the accompanying drawings.

According to the present invention, it is possible to provide a damping force control valve which is excellent in position controllability of the valve body at the time of the minute opening, and which has a wide range of the controllable opening degree.

It is a longitudinal section showing a damping force control valve concerning one embodiment of the present invention typically. It is a longitudinal cross-sectional view which shows typically a mode at the time of the micro opening degree (b), the full opening state (c) at the time of full closing (a) of the damping force control valve shown in FIG. It is a longitudinal cross-sectional view which shows typically a mode at the time of the micro opening degree (b), and the full closing (c) at the time of full closing (a) of the damping force control valve which concerns on other embodiment of this invention. (A)-(h) is a longitudinal cross-sectional view which shows typically the example of the shape of the downstream end of a valve body. (A) to (i) are side views schematically showing modifications of the shape of the downstream end of the valve body. It is a hydraulic circuit figure which shows an example of the shock absorber provided with the damping force control valve shown in FIG. It is a hydraulic circuit figure which shows an example of the shock absorber provided with the damping force control valve shown in FIG. It is a partial expanded sectional view which shows typically the conventional damping force control valve in the time of micro opening degree.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view schematically showing a damping force control valve 10 according to an embodiment of the present invention.
FIG. 1 shows a state in which the damping force control valve 10 is fully closed.
In the following description, the direction in which the working fluid of the first working fluid chamber 30 is discharged through the first port 30a is referred to as the downstream direction D. Further, a direction opposite to the downstream direction D along the axial direction S of the valve body 20 is referred to as an opposite direction U.

The damping force control valve 10 includes a hollow cylindrical outer cylinder 11 (housing). The outer cylinder 11 includes an opening 11 a on the downstream direction D side and an opening 11 b on the opposite direction U side. The inner cylinder 12 is fitted into the opening 11 b of the outer cylinder 11. The opposite direction U side end of the outer cylinder 11 is bent inward and abuts against the inner cylinder 12 in the axial direction S, whereby the outer cylinder 11 and the inner cylinder 12 are fixed. The outer cylinder 11 has a flange portion 11 c that annularly protrudes toward the axial center at a substantially central portion in the axial direction S. The flange portion 11c has a cylindrical portion 11d extending toward the opening 11b at its inner edge. The cylindrical guide member 13 is inserted into the cylindrical portion 11 d. The guide member 13 has a flange portion 13a on the downstream direction D side. The

flanges

11c and 13a are in contact with each other. Thereby, in the outer cylinder 11, the movement to the opposite direction U side of the guide member 13 is regulated. The guide member 13 is provided with a guide hole 13b. A hollow cylindrical valve body 20 is slidably inserted into the guide hole 13b.

The valve body 20 has an end face 20a on the downstream direction D side and an end face 20b on the opposite direction U side. The valve body 20 is formed with a passage 21 extending from the end face 20a to the end face 20b. The passage 21 includes a large diameter portion 21 a including an end surface 20 a on the downstream direction D side, and a communication portion 21 b extending toward the second working fluid chamber 40 from the opposite direction U side end of the large diameter portion 21 a. The communicating portion 21 b is a columnar space, and the diameter is substantially constant. The opening area of the passage 21 (large diameter part 21a) at the end face 20a on the downstream direction D side of the valve body 20 is larger than the opening area of the communication part 21b. In the passage 21, the diameter of the communication portion 21b is the smallest. That is, in the damping force control valve 10, the communication portion 21b is the smallest diameter portion in the passage 21. The boundary between the large diameter portion 21 a and the communication portion 21 b in the axial direction S is located in the first working fluid chamber 30.

The end face 20 a on the downstream direction D side of the valve body 20 faces the first port 30 a of the first working fluid chamber 30. The end surface 20a does not abut on the wall surface (bottom surface 26a) of the first working fluid chamber 30. The valve body 20 is made of a nonmagnetic material. A hollow cylindrical support member 14 is installed on the opposite direction U side of the cylindrical portion 11 d. The support member 14 faces the cylindrical portion 11 d coaxially with the cylindrical portion 11 d. The supporting member 14 has an opening 14a formed on the downstream direction D side, an opening 14b formed on the opposite direction U side, and a guide portion 14c which annularly protrudes toward the axial center at a substantially central portion in the axial direction S Have. An annular bearing 20c is installed on the inner peripheral side of the guide portion 14c. The valve body 20 is inserted into the bearing 20c, and the bearing 20c slidably supports the valve body 20. A spring receiving member 15 is fixed on the inner peripheral surface of the support member 14 closer to the opening 14 b than the guide portion 14 c. An annular seal 16 (e.g., an O-ring) for sealing between the support member 14 and the spring receiving member 15 is provided on the outer peripheral surface of the spring receiving member 15. A cap 17 is provided at the opposite direction U side end of the support member 14. The cap 17 closes the opening 14 b. In the support member 14, a second working fluid chamber 40 is formed between the guide portion 14 c and the spring receiving member 15.

The end face 20 b of the valve body 20 is exposed in the second working fluid chamber 40. In the second working fluid chamber 40, the coil spring 18 is supported by the end face 20 b of the valve body 20 and the spring receiving member 15. The coil spring 18 biases the valve body 20 in the downstream direction D. A cylindrical cylindrical member 19 is provided to connect the cylindrical portion 11 d and the support member 14. The cylindrical member 19 is made of a nonmagnetic material. In the outer cylinder 11, a bobbin 22 is provided. The bobbin 22 covers the outer peripheral surface of the support member 14 and the outer peripheral surface of the cylindrical member 19. A solenoid coil 23 is wound around the bobbin 22. An annular plate-like cap 24 is attached between the bobbin 22 and the inner cylinder 12 on the inner peripheral surface of the outer cylinder 11. The cap 24 is made of a magnetic material (for example, iron).

On the outer peripheral surface of the valve body 20, a cylindrical plunger 25 is fixed between the guide member 13 and the guide portion 14c. The inner diameter of the cylindrical portion 11 d is larger than the outer diameter of the plunger 25. Further, in the support member 14, the inner diameter of the portion closer to the opening 14 a than the guide portion 14 c is larger than the outer diameter of the plunger 25. Therefore, the plunger 25 can move in the axial direction S between the guide member 13 and the guide portion 14c. In the damping force control valve 10, by adjusting the magnetic flux density of the magnetic field generated by the solenoid coil 23, the plunger 25 can be moved in the axial direction S between the guide member 13 and the guide portion 14c. Thereby, the valve body 20 moves in the axial direction S. The solenoid coil 23 and the coil spring 18 constitute a solenoid. The installation space 25 a of the plunger 25 is formed by the cylindrical portion 11 d, the guide member 13, the guide portion 14 c and the cylindrical member 19. The working fluid HO is also filled in the installation space 25a. The space 25 a communicates with the first working fluid chamber 30 via a gap between the outer peripheral surface of the valve body 20 and the inner peripheral surface of the guide member 13. The space 25 a communicates with the second working fluid chamber 40 through a gap between the outer peripheral surface of the valve body 20 and the inner peripheral surface of the guide portion 14 c.

A substantially cylindrical valve head 26 with a bottom is disposed on the side of the opening 11 a in the outer cylinder 11 so as to contact the flange portion 13 a of the guide member 13. A first port 30 a is formed at the center of the bottom surface 26 a of the valve head 26. The first port 30 a is installed at a position facing the end face 20 a of the valve body 20. In the valve head 26, the working fluid path 31 extends from the first port 30a in the downstream direction D. The valve head 26 is provided with a second port 30 b on the outer peripheral wall 26 c of the valve head 26. In the valve head 26, the working fluid passage 32 extends radially from the second port 30b.

A first working fluid chamber 30 is constituted by the valve head 26 and the guide member 13. The first working fluid chamber 30 is provided with a guide hole 13 b. The first working fluid chamber 30 and the second working fluid chamber 40 are disposed opposite to each other with the valve body 20 interposed therebetween. The end face 20 a of the valve body 20 is disposed on the first working fluid chamber 30 side. The first working fluid chamber 30 and the second working fluid chamber 40 are in communication via the passage 21 of the valve body 20. A space in the first working fluid chamber 30 is located around the outer peripheral surface of the valve body 20. The working fluid flows from the working fluid passage 32 along the radial direction of the valve body 20 into the first working fluid chamber 30.

In the first working fluid chamber 30, the downstream side surface 13c of the guide member 13 and the bottom surface 26a of the valve head 26 are opposed in the axial direction S. In the first working fluid chamber 30, a circlip 33 as a fixture is fixed to the outer periphery of the valve body 20. In addition, a fixing tool is not limited to a circlip.

Between the circlip 33 and the bottom surface 26 a of the valve head 26 on the downstream direction D side of the circlip 33, a coil spring 34 as a biasing body is installed. The valve body 20 is inserted into the coil spring 34. As the downstream direction D is approached, the diameter of the coil spring 34 increases. Therefore, the flow of the working fluid from the working fluid passage 32 to the working fluid passage 31 via the first working fluid chamber 30 is less likely to be blocked by the coil spring 34.

A coil spring 35 as an urging body is installed between the circlip 33 and the downstream side surface 13c of the guide member 13 on the opposite direction U side of the circlip 33 as a fixing tool. The valve body 20 is inserted through the coil spring 35. As the reverse direction U is approached, the diameter of the coil spring 35 increases.

The coil springs 18, 34, 35 apply a force to the valve body 20 along the axial direction S. In the damping force control valve 10, when the solenoid coil 23 is not energized, the valve body 20 is moved by the coil springs 18, 34, 35, and the valve body 20 closes the first port 30a. In addition, an urging body is not limited to a coil spring, For example, conventionally well-known urging bodies, such as a leaf | plate spring, are employable.

Next, the operation of the damping force control valve will be described with reference to FIG.
FIG. 2 is a longitudinal sectional view schematically showing the damping force control valve shown in FIG. 1 when fully closed (a), when it is slightly open (b), and when it is fully opened (c).

When the solenoid coil 23 is not energized, as shown in FIG. 2A, the valve body 20 is positioned on the downstream direction D side by the coil springs 18, 34, 35, and the first port 30a is closed. Thereby, the flow path (flow path T in FIGS. 2B and 2C) from the working fluid path 32 to the working fluid path 31 via the first working fluid chamber 30 is blocked.

Slant processing is applied to a part (approximately half) of the end face 20a (see FIG. 1) of the valve body 20. Thus, the end face 20a includes the flat portion 20d and the inclined portion 20e which is inclined in the opposite direction D from the flat portion 20d. In FIG. 2A, the flat portion 20d is located on the downstream direction D side of the first port 30a and enters the working fluid passage 31. The edge on the opposite direction U side of the inclined portion 20 e is present at the same position as the first port 30 a in the axial direction S of the valve body 20.

When the solenoid coil 23 is energized and the damping force control valve 10 is adjusted to a minute opening degree (for example, an interval of about 0.5 mm), as shown in FIG. 2B, the flat portion 20d and the first port 30a Are present at the same position in the axial direction S of the valve body 20. On the other hand, there is an interval between the inclined portion 20e and the first port 30a. This interval is the flow path T of the working fluid. At the minute opening degree, since the flow path T of the working fluid is narrow, the flow X of the working fluid passing through the flow path T is relatively fast. The flow X of the working fluid collides with the inner wall of the working fluid passage 31, and a part of the flow X goes in the downstream direction D as it is. Also, a part of the flow X becomes a flow Y in the opposite direction U. Since the large diameter portion 21a is formed at the downstream direction D side end of the valve body 20, the flow Y of the working fluid swirls in the large diameter portion 21a and diffuses into the flow X of the working fluid while diffusing. It is easy to return. That is, the large diameter portion 21a has a rectifying action, and regulates the flow of the working fluid in the downstream direction D. Thereby, the increase in the pressure difference between the working fluid passage 31 and the second working fluid chamber 40 is prevented, and the force applied to the valve body 20 toward the first port 30 a can be suppressed. Further, since the large diameter portion 21a is formed, the distance by which the flow X of the working fluid flows along the end face 20a (the inclined portion 20e) is short. Accordingly, it is possible to suppress the force applied to the valve body 20 toward the first port 30a. As a result, the damping force control valve 10 is excellent in position controllability of the valve body 20 at the time of the minute opening degree, and the range of the controllable opening degree is wide, and higher responsiveness can be realized.

Further, as shown in FIG. 2B, when a part of the outer peripheral edge of the valve body 20 is located in the first port 30a, the flow path T is a part of the outer peripheral edge of the valve body 20 and the first It is a distance from a part of the outer peripheral edge of one port 30a. Therefore, the change in the opening area of the flow passage T with respect to the stroke (displacement amount in the axial direction S) of the valve body 20 is relatively small.

When the solenoid coil 23 is energized and the opening of the damping force control valve 10 is adjusted to the maximum (for example, an interval of about 2 mm), as shown in FIG. 2C, the valve body 20 is moved from the first port 30a. Leave. When the valve body 20 and the first port 30a are separated, the flow path T is a distance between the entire outer peripheral edge of the valve body 20 and the entire outer peripheral edge of the first port 30a. Therefore, the change in the opening area of the flow passage T with respect to the stroke of the valve body 20 is relatively large.

Thus, in the damping force control valve 10, the change in the opening area of the flow passage T with respect to the stroke of the valve body 20 is small when the opening degree is small, and the opening of the flow path T with respect to the stroke of the valve body 20 when the opening degree is large. The change in area is large.

Next, another embodiment of the present invention will be described.
FIG. 3 is a longitudinal sectional view schematically showing the damping force control valve according to another embodiment of the present invention when the valve is fully closed (a), slightly open (b) and fully closed (c). is there. 3 is the same as FIG. 2 except for the shape of the downstream end D side end of the valve body 20, so in FIG. The explanation is omitted or simplified.

In the damping force control valve 10 shown in FIG. 3, the end face 20 a ′ on the downstream direction D side of the valve body 20 is flat. When the solenoid coil 23 is not energized, as shown in FIG. 3A, the valve body 20 is positioned on the downstream direction D side by the coil springs 18, 34 and 35, and the first port 30a is closed. The end face 20 a ′ of the valve body 20 is present at the same position as the first port 30 a in the axial direction S of the valve body 20.

When the solenoid coil 23 is energized and the damping force control valve 10 is adjusted to a minute opening degree, as shown in FIG. 3B, the end face 20a of the valve body 20 (FIG. 3A) and the first port 30a opens. The distance between the entire outer peripheral edge of the valve body 20 and the entire outer peripheral edge of the first port 30a is the flow path T of the working fluid. At the minute opening degree, since the flow path T of the working fluid is narrow, the flow X of the working fluid passing through the flow path T is relatively fast. The working fluid flows X passing through the flow path T collide with each other, and a part of the flow X directly proceeds in the downstream direction D. Also, a part of the flow X becomes a flow Y in the opposite direction U. Since the large diameter portion 21a is formed at the downstream direction D side end of the valve body 20, the flow Y of the working fluid swirls in the large diameter portion 21a and diffuses into the flow X of the working fluid while diffusing. It is easy to return. Thereby, the increase in the pressure difference between the working fluid passage 31 and the second working fluid chamber 40 is prevented, and the force applied to the valve body 20 toward the first port 30 a can be suppressed. In addition, since the large diameter portion 21a is formed, the distance by which the flow X of the working fluid flows along the end face 20a is short. Accordingly, it is possible to suppress the force applied to the valve body 20 toward the first port 30a. As a result, the damping force control valve 10 is excellent in position controllability of the valve body 20 at the time of the minute opening degree, and the range of the controllable opening degree is wide, and higher responsiveness can be realized. Thereafter, when the opening degree of the damping force control valve 10 is adjusted to the maximum, as shown in FIG. 3C, the flow passage T is widely secured.

Next, a modification of the shape of the downstream end D side end of the valve body 20 will be described with reference to FIGS. 4 and 5.
4 (a) to 4 (h) are longitudinal sectional views schematically showing examples of the shape of the downstream end of the valve body 20. As shown in FIG.
In the figure, Q is the radius of the communicating portion 21b. V is a difference in radius between the large diameter portion 21a and the communication portion 21b. W is the thickness of the valve body 20 at the large diameter portion 21a. Q + V is the radius of the large diameter portion 21a. V + W is the thickness of the valve body 20 in the communication portion 21 b. H is the depth of the cylindrical portion of the large diameter portion 21a, and K is the depth of the tapered portion. In FIGS. 4A to 4H, Q <W + V, Q> W, and V> W. The dimensional relationship of Q, V, W is an example of this embodiment, and the dimensional relationship of Q, V, W in the present invention is not limited to this example.

In FIG. 4A, the large diameter portion 21a is cylindrical, and there is a step between the large diameter portion 21a and the communication portion 21b. The depth H satisfies H <Q, H <V, H> W.

In FIG. 4B, the large diameter portion 21a is cylindrical, and there is a step between the large diameter portion 21a and the communication portion 21b. The depth H satisfies H> Q, H> V, H> W.

FIG. 4 (c) is the same as FIG. 4 (a) except that a taper portion 26b is formed on the periphery of the first port 30a of the valve head 26. The depth J of the tapered portion 26b satisfies J <H.

In FIG. 4D, the large diameter portion 21a is composed of a cylindrical portion located on the downstream direction D side and a tapered portion located on the opposite direction U side. Further, a tapered portion 26 b is formed on the periphery of the first port 30 a of the valve head 26. The depth H satisfies H <Q, H <V, H> W, H> J, and H <K. Also, the depth K satisfies K> Q, K> V, K> W, K> J. Also, J and W satisfy W> J. When viewed from the downstream direction D side of the valve body 20, an angle formed by the axial direction S of the valve body 20 and the tapered portion of the large diameter portion 21a is 30 °.

In FIG. 4E, the large diameter portion 21a is composed of a cylindrical portion located on the downstream direction D side and a tapered portion located on the opposite direction U side. Further, a tapered portion 26 b is formed on the periphery of the first port 30 a of the valve head 26. 4 (e) is the same as FIG. 4 (d) except that J is larger than FIG. 4 (d). The depth J of the tapered portion 26b satisfies J> W, J <H, J <Q, and J <V.

In FIG. 4 (f), the large diameter portion 21a has a tapered shape. The depth K satisfies K> Q, K> V, K> W. When viewed from the downstream direction D of the valve body 20, an angle formed by the axial direction S of the valve body 20 and the tapered portion of the large diameter portion 21a is, for example, 30 °.

In FIG. 4 (g), the large diameter portion 21a has a tapered shape. The depth K satisfies K> Q, K <V, K> W. When viewed from the downstream direction D of the valve body 20, an angle formed by the axial direction S of the valve body 20 and the tapered portion of the large diameter portion 21a is, for example, 45 °.

In FIG. 4 (h), the large diameter portion 21a has a tapered shape. The depth K satisfies K <Q, K <V, K> W. When viewed from the downstream direction D side of the valve body 20, an angle formed by the axial direction S of the valve body 20 and the tapered portion of the large diameter portion 21a is, for example, 60 °.

According to the valve body 20 having the shape shown in FIGS. 4 (a) to 4 (h), as shown in FIGS. 2 (b) and 3 (b), the flow Y of the working fluid in the opposite direction U is large. It returns to the flow X of the working fluid in the downstream direction D while diffusing in a vortex in the diameter portion 21a. Thereby, generation | occurrence | production of the pressure difference of the communication part 21b and the working fluid path 31 can be prevented. Although the angle which the axial direction S of the valve body 20 and the taper part of the large diameter part 21a comprise is not specifically limited, For example, it is preferable that it is 22.5 degrees or more.

5 (a) to 5 (i) are side views schematically showing modifications of the shape of the downstream end of the valve body.

In FIG. 5A, the cylindrical large diameter portion 21a is formed so as to include the end face 20a on the downstream direction D side of the valve body 20. A communicating portion 21b is formed on the opposite direction U side of the large diameter portion 21a. The axis C of the valve body 20 is the same as the axis of the communicating portion. The axis C of the valve body 20 is different from the axis C 'of the large diameter portion 21a. That is, the barycentric position of the large diameter portion 21a and the barycentric position of the valve body 20 are different. In addition, an outer peripheral tapered portion 20f is formed on the outer peripheral edge of the end face 20a.

In FIG. 5 (b), the large diameter portion 21 a is formed so as to include the end face 20 a on the downstream direction D side of the valve body 20. The large diameter portion 21a is composed of a cylindrical portion located on the downstream direction D side and a tapered portion located on the opposite direction U side, and the axial line C 'is between the cylindrical portion and the tapered portion. Although common, the axis C 'is different from the axis C of the valve body 20. That is, the outer peripheral tapered portion 20f is formed on the outer peripheral edge of the end face 20a.

In FIG. 5C, the large diameter portion 21a is formed so as to include the end face 20a on the downstream direction D side of the valve body 20. The large diameter portion 21a has a tapered shape. An outer peripheral tapered portion 20f is formed on the outer peripheral edge of the end face 20a.

In FIG. 5D, the cylindrical large diameter portion 21a is formed so as to include the end face 20a on the downstream direction D side of the valve body 20. The axes of the valve body 20 and the large diameter portion 21a coincide with each other. In addition, an outer peripheral tapered portion 20f is formed on the outer peripheral side of the end face 20a.

In FIG. 5E, the large diameter portion 21a is formed so as to include the end face 20a on the downstream direction D side of the valve body 20. The large diameter portion 21a is composed of a cylindrical portion located on the downstream direction D side and a tapered portion located on the opposite direction U side, and the axis of the valve body 20, the cylindrical portion and the tapered portion And the axis of. In addition, an outer peripheral tapered portion 20f is formed on the outer peripheral side of the end face 20a.

FIG. 5 (f) has the same shape as the valve body 20 shown in FIG. 1 and FIG. 2, but FIG. 5 (f) shows the outer peripheral taper 20f not shown in FIG. 1 and FIG. ing.
In (f) of FIG. 5, the large diameter portion 21 a is formed on the downstream direction D side of the valve body 20. The large diameter portion 21a has a tapered shape. An outer peripheral tapered portion 20f is formed on the outer peripheral edge of the end face 20a. Further, approximately half of the end face 20a of the valve body 20 is slanted, and the end face 20a includes a flat portion 20d and an inclined portion 20e which is inclined in the opposite direction D from the flat portion 20d. The inclined portion 20e is flat.

The valve body 20 of FIG. 5 (g) is the same as FIG. 5 (d) except that the end face 20a is subjected to slant processing as in FIG. 5 (f).

The valve body 20 of FIG. 5 (h) is the same as FIG. 5 (e) except that the end face 20a is subjected to slant processing as in FIG. 5 (f).

The valve body 20 of FIG. 5 (i) is the same as the valve body 20 of FIG. 5 (f) except that the inclined portion 20e is a curved surface (convex surface).

The valve body 20 of FIG. 5 (j) is the same as FIG. 5 (f) except that the axis C of the valve 20 and the axis C 'of the tapered large diameter portion 21a are shifted. Although the angle which the outer periphery taper part 20f and the axial direction S of the valve body 20 comprise is not specifically limited, For example, it is preferable that it is 10 degrees or less.

Next, a shock absorber 100 according to an embodiment of the present invention will be described.
6 and 7 are hydraulic circuit diagrams showing a shock absorber 100 provided with the damping force control valve 10 shown in FIG.

The shock absorber 100 is provided with a hydraulic cylinder 112. In the hydraulic cylinder 112, a piston assembly 144 is installed. The hydraulic cylinder 112 is divided into two working

fluid chambers

158 and 160 by a piston assembly 144. One end of the piston rod 162 is inserted into the hydraulic cylinder 112 from one end side of the hydraulic cylinder 112 and is fixed to the piston assembly 144. The other end of the piston rod 162 is connected to the vehicle body side (not shown) of the vehicle. The other end of the hydraulic cylinder 112 is connected to the wheel side (not shown) of the vehicle body.

The piston assembly 144 includes damping

valves

148, 150 comprised of a plurality of shims. The damping valve 148 can flow the working fluid from the working fluid chamber 160 to the working fluid chamber 158, at which time a damping force is generated (elongation damping). The working fluid can not flow in the opposite direction. The damping valve 150 can flow the working fluid from the working fluid chamber 158 to the working fluid chamber 160, at which time a damping force is generated (shrinkage damping). The working fluid can not flow in the opposite direction.

A damping force adjustment device 116 is installed between the working fluid chamber 158 and the reservoir tank 114. In the damping force adjustment device 116, the damping force control valve 10, a damping valve 116b composed of a plurality of shims, and a check valve 116c are installed in parallel. The damping valve 116 b can flow the working fluid from the hydraulic cylinder 112 side to the reservoir tank 114 side, and can not flow the working fluid in the opposite direction. The check valve 116 c can flow the working fluid from the reservoir tank 114 side to the hydraulic cylinder 112 side. The working fluid can not flow in the opposite direction. The working fluid O and the gas G are contained in the reservoir tank 114, and the working fluid O and the gas G are in contact at the interface OS. The working fluid O is, for example, working oil or the like. The gas G is, for example, nitrogen gas or air.

In the state shown in FIGS. 2B and 2C and FIGS. 3B and 3C, the damping force control valve 10 uses the working fluid from the working fluid passage 32 via the first working fluid chamber 30. It can flow in the direction toward the working fluid path 31. Further, the damping force control valve 10 can also flow the working fluid in the opposite direction. Further, as shown in FIGS. 6 and 7, the damping force control valve 10 is installed as a bypass for the damping valve 116b.

When the piston assembly 144 moves in the X1 direction, the working fluid of the volume of the piston rod 162 that has entered the hydraulic cylinder 112 is discharged from the hydraulic cylinder 112 and moves to the reservoir tank 114. The damping force control valve 10 and the damping valve 116b are in a bypass relationship with each other, and the working fluid HO discharged from the hydraulic cylinder 112 passes through the damping force control valve 10 and the damping valve 116b as shown in FIG. It flows into the reservoir tank 114. In the damping force control valve 10, the working fluid flows in the direction of being discharged from the first working fluid chamber 30 via the first port 30a. The resistance when flowing through the damping force adjusting device 116 (the damping valve 116b and the damping force control valve 10) increases the pressure of the working fluid in the hydraulic cylinder 112 and resists the movement of the piston rod 162 in the X1 direction (cylinder The pressure of the working fluid (cross sectional area of the piston rod 162), that is, the compression damping force (1) is generated. Here, when the opening degree of the damping force control valve 10 is adjusted, the ratio of the flow rate between the damping valve 116 b and the damping force control valve 10 changes, so that the resistance of the damping valve 116 is adjusted and the compression acting on the piston rod 162 Damping force is adjusted. Also, the working fluid flows from the working fluid chamber 158 toward the working fluid chamber 160 also in the damping valve 150 of the piston assembly 144, and the resistance at that time acts on the piston assembly 144 and the compression damping force (2) on the piston rod 162 Is added as

On the other hand, when the piston assembly 144 moves in the X2 direction, as shown in FIG. 7, the working fluid of the volume from which the piston rod 162 is withdrawn passes through the check valve 116 c without resistance and returns to the hydraulic cylinder 112.
Thus, in the shock absorber 100, part of the damping force at the time of compression can be adjusted by the damping force control valve 10. Specifically, in the shock absorber 100, the compression damping force (1) generated by the approach of the piston rod 162 in the damping forces during compression (ie, the above-mentioned compression damping forces (1) and (2)) is adjusted can do.
The present invention is not limited to this example, and for example, the shock absorber 100 may be capable of adjusting all of the damping force at the time of compression by the damping force control valve 10. Specifically, in the example shown in FIG. 6 and FIG. 7, instead of the damping valve 150, a check valve may be provided to flow the working fluid from the working fluid chamber 158 to the working fluid chamber 160. In the shock absorber 100 configured as described above, when the piston assembly 144 moves in the X1 direction, the above-described compression damping force (1) is generated, but the above-described compression damping force (2) is not generated. Therefore, by adjusting the compression damping force (1), it is possible to adjust all of the damping forces at the time of compression.

As described above, according to the damping force control valve 10, in the passage 21 of the valve body 20, the opening area at the end on the downstream direction D side is larger than the opening area of the communicating portion 21b as the smallest diameter portion in the passage 21. Therefore, the increase in the pressure difference between the working fluid passage 31 on the downstream side and the passage 21 can be suppressed, and the force applied to the valve body 20 toward the first port 30 a can be suppressed. Further, since the distance by which the flow X of the working fluid passing between the end face 20a of the valve body 20 and the first port 30a flows along the surface of the end face 20a of the valve body 20 is relatively short, the end face 20a of the valve body 20 The pressure drop on the surface of the valve body 20 is prevented, and the force applied to the valve body 20 toward the first port 30a can be suppressed. Therefore, the position controllability of the valve body 20 at the time of the minute opening degree is excellent, and the range of the opening degree that can be accurately controlled is wide, and high responsiveness can be realized.

The damping force control valve 10 further includes coil springs 34 and 35 through which the valve body 20 is inserted in the first working fluid chamber 30 and applying a force to the valve body 20 along the axial direction S of the valve body 20. In the passage 21 in the valve body 20, the opening area of the downstream end is smaller than the inner diameter area of the coil springs 34, 35. The pressure transmission or the movement of the working fluid in the passage 21 at the time of the movement of the valve body 20 is smooth, and the response can be further improved.

Further, the passage 21 has a large diameter portion 21a including the downstream end, and the diameter of the large diameter portion 21a is larger than the diameter of the communication portion 21b. In the large diameter portion 21a, a portion of the flow X of the working fluid returns to the flow F of the working fluid. Further, the flow of working fluid passing between the end face 20a of the valve body 20 and the first port 30a is relatively short, and the distance flowing along the surface of the end face 20a of the valve body 20 is relatively short. The force applied to the body 20 can be suppressed.

In the valve body 20 shown to Fig.4 (a), the level | step difference to which the diameter of the channel | path 21 changes is provided between the large diameter part 21a and the communication part 21b. Thus, the large diameter portion 21a preferably has a step. Vortex generation in the large diameter portion 21a is facilitated.

In the valve body 20 shown in FIG. 4F, the large diameter portion 21a has a tapered shape in which the diameter of the passage 21 increases as it approaches the downstream end D side end. Thus, the large diameter portion 21a preferably has a tapered shape. Vortex generation in the large diameter portion 21a is facilitated.

In the valve body 20 shown to Fig.5 (a), in the axial direction S view of the valve body 20, axial center C 'of the large diameter part 21a and axial center C of the valve body 20 differ. That is, the position of the center of gravity of the large diameter portion 21 a is different from the position of the center of gravity of the valve body 20. The force exerted in the radial direction of the valve body 20 by the flow X of the working fluid is not parallel on the axis C of the valve body 20, and the valve body 20 is stabilized along the wall of the guide hole 13b.

In the damping force control valve 10, substantially only the fluid exists in the passage 21 of the valve body 20. In the passage 21, a member such as a biasing body is not attached. The pressure transmission or the movement of the working fluid in the passage 21 at the time of the movement of the valve body 20 is smooth.

In the damping force control valve 10, the flow direction of the working fluid in the downstream direction D is along the axial direction S of the valve body 20. Since the working fluid can be smoothly discharged out of the first working fluid chamber 30, the responsiveness is excellent.

Although the above-mentioned embodiment explained the case where damping force control valve 10 was connected to hydraulic cylinder 112, the arrangement method of a damping force adjustment device is not limited to the above-mentioned example. Although the shock absorber 100 shown in FIGS. 6 and 7 is configured to allow the working fluid to flow in both directions with respect to the damping force control valve 10, the present invention is not limited to this example. In the present invention, the working fluid is preferably configured to flow in a direction in which the working fluid is discharged from at least the first working fluid chamber 30 via the first port 30a. In addition, the shock absorber 100 may be configured to flow the working fluid in a direction to discharge the working fluid from the first working fluid chamber 30 via the first port 30a at the time of extension, and at the time of retraction, the first working fluid chamber 30 may be configured to flow the working fluid in the direction of discharging the working fluid via the first port 30a.

Although the above-mentioned embodiment explained cylindrical valve body, shape of a valve body is not limited to the above-mentioned example. For example, the valve body may have a hollow rectangular tube shape. Further, the shape of the working fluid passage is not limited to the above-described example, and the cross section of the working fluid passage may be polygonal or elliptical. Further, in the present embodiment, the case where a proportional solenoid is used as the solenoid has been described. However, the present invention is not limited to this example, and an ON / OFF solenoid may be used as the solenoid, for example.

Although the preferred embodiments of the present invention have been described above, it is apparent that various modifications can be made without departing from the scope and spirit of the present invention. The scope of the present invention is limited only by the appended claims.

10 damping force control valve 20 valve body 21 passage 21a large diameter portion 21b communication portion 23 solenoid coil 26 valve bed 30 first working fluid chamber 30a first port 40 second working fluid chamber

Claims

Damping force control valve,
The damping force control valve is
A hollow cylindrical valve body linearly reciprocated by a solenoid;
A first working fluid chamber including a guide hole through which the valve body is inserted, and a port formed at a position facing the end face of the valve body;
A second working fluid chamber in communication with the first working fluid chamber via a passage in the valve body;
Equipped with
A gap between the end face of the valve body and the port is a flow passage through which the working fluid passes,
The opening degree of the flow passage is changed by the position of the end face of the valve body, whereby the damping force is controlled,
When the opening degree of the flow path is minimum, the gap between the valve body and the port is fully closed, and when the opening degree of the flow path is maximum, the valve body is separated from the port;
In the passage in the valve body, the opening area of the downstream end of the flow direction in which the working fluid in the first working fluid chamber is discharged out of the first working fluid chamber through the port is the largest opening in the passage. Larger than the opening area of the small diameter portion.
The damping force control valve according to claim 1, wherein
The damping force control valve includes an annular biasing body through which the valve body is inserted in the first working fluid chamber and which applies a force to the valve body along an axial direction of the valve body.
In the passage in the valve body, the opening area of the downstream end is smaller than the inner diameter area of the biasing body.
The damping force control valve according to claim 1 or 2, wherein
The passage has a large diameter portion including the downstream end, and the diameter of the large diameter portion extends from the opposite end of the downstream end of the large diameter portion toward the second working fluid chamber Larger than the diameter of the part.
The damping force control valve according to claim 3, wherein
The large diameter portion has a step in which the diameter of the passage changes.
The damping force control valve according to claim 3 or 4, wherein
The large diameter portion has a tapered shape in which the diameter of the passage increases as it approaches the downstream end.
The damping force control valve according to any one of claims 3 to 5, wherein
The position of the center of gravity of the large diameter portion is different from the position of the center of gravity of the valve in the axial direction of the valve.
The damping force control valve according to any one of claims 1 to 6, wherein
Substantially only fluid is present in the passage of the valve body.
The damping force control valve according to any one of claims 1 to 7, wherein
The flow direction in which the working fluid in the first working fluid chamber is discharged to the outside of the first working fluid chamber through the port is along the axial direction of the valve body.
A shock absorber,
The shock absorber is provided with the damping force control valve according to any one of claims 1 to 8.
The shock absorber according to claim 9,
The shock absorber is configured to flow the working fluid in a direction in which the working fluid in the first working fluid chamber is discharged to the outside of the first working fluid via the port in the damping force control valve.