WO2013122251A1

WO2013122251A1 - Damping force control valve and shock absorber

Info

Publication number: WO2013122251A1
Application number: PCT/JP2013/053845
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: JP2013170601A

Abstract

A damping force control valve (10) having improved damping force control characteristics during minute opening. The damping force control valve (10) comprises: a 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). The damping force is controlled by the degree of opening of a communications passage (52) that is the gap between an end surface (20a) of the valve body (20) and the port (30a). Variation of the cross-sectional area of the communications passage relative to the stroke of the valve (20), during minute opening, is reduced by forming a sloping section (20e) and an outer peripheral tapered section (20f), at a position lower than a closed section (50) of the valve body (20) being the position where the communications passage (52) is closed.

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 communicates with a second working fluid chamber (not shown) via the passage 200 e of the valve body 200 inserted into the guide hole 234 c. 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. Furthermore, since the valve body 200 is in the form of a hollow cylinder, and includes the passage 200e that communicates the first working fluid chamber 234 with the second working fluid chamber, the valve 200 is a valve compared to when using a columnar valve body. The amount (volume) of the working fluid with which the valve body 200 pushes away when the body 200 moves back and forth is small. Further, since the first working fluid chamber 234 and the second working fluid chamber are in communication with each other, a pressure difference between the first working fluid chamber 234 and the second working fluid chamber is unlikely to occur. Therefore, the valve body 200 is unlikely to receive the resistance of the working fluid when performing linear reciprocation. 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.

Further, in the damping force control valve shown in Patent Document 1, as described above, since it is difficult for the valve body 200 to receive the resistance of the working fluid when performing linear reciprocation, the drive power of the valve body 200 can be lowered. . As a result, since a relatively small solenoid can be used, downsizing and weight reduction of the damping force control valve become possible. As described above, in the damping force control valve shown in Patent Document 1, it is possible to realize both the improvement of the response and the reduction in size and weight of the valve.
In the field of vehicles such as motorcycles and automobiles, there is a strong demand for reducing the installation space of the valve as much as possible because the installation space of the equipment is limited. In addition, from the viewpoint of improvement of running performance, the demand for weight reduction of the valve is also very strong. Therefore, the miniaturization and weight reduction of the valve have very great technical significance in the present field.

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 port) has a minute opening degree. The valve body 200 may not be stable at the target position.

Further, in the damping force control valve shown in Patent Document 1, the distance between the end face 200c of the valve body 200 and the port 234b is the flow path of the working fluid, and the opening degree of the flow path depends on the position of the end face 200c of the valve body 200. Be changed. Specifically, when the end face 200c of the valve body 200 and the port 234b are positioned on the same plane, the flow path is fully closed. When the valve body 200 is slightly moved from the fully closed state, the valve body 200 and the port 234b are separated, and the state of the minute opening as shown in FIG. 8 is obtained. Therefore, at the minute opening degree, the area change of the flow path of the working fluid with respect to the position change of the end face 200c is large, and the control characteristic of the damping force becomes sharp. In this state, the amount of reaction of the output with respect to the amount of change in the input for damping force control is large, so there is a problem that it is difficult to perform damping force control accurately at the time of the minute opening.

As described above, the damping force control valve disclosed in Patent Document 1 has room for improvement in the position controllability of the valve body 200 at the time of the minute opening.

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.
In the damping force control valve shown in FIG. 8, the valve body 200 has a hollow cylindrical shape, and the first working fluid chamber 234 and the second working fluid chamber (not shown) are separated via the passage 200 e of the valve body 200. It is in communication. Therefore, as described above, the valve body 200 is unlikely to receive the resistance of the working fluid when performing the linear reciprocating motion. As a result, the movement of the valve body 200 with low power becomes possible, and the downsizing and weight reduction of the valve are realized. However, in other words, this means that the valve body 200 is susceptible to fluid force.

In the damping force control valve shown in FIG. 8, when the distance between the end face 200c of the valve body 200 and the port 234b (flow path of working fluid) is narrow, a force is applied to the vehicle to extend or contract the suspension, and the working fluid is the first action When the fluid chamber 234 is discharged to the outside of the first working fluid chamber 234 via the above-mentioned interval, the flow S of the working fluid is accelerated because the above-mentioned interval is narrow. On the other hand, when fully closed, the flow S of the working fluid does not occur. As described above, when the valve body 200 slightly moves at the minute opening degree, the speed of the flow S of the working fluid changes significantly.

When the speed of the flow S of the working fluid changes significantly, the fluid force on the valve body 200 also largely changes. As described above, since the valve body 200 is susceptible to fluid force, a large fluctuation in fluid force causes the position of the valve body 200 to be unstable. Therefore, although it is desirable to perform position control of the valve body with high accuracy, as described above, the control characteristics of the damping force at the time of the minute opening degree are sharp, and position control of the valve body 200 is difficult. Also, each time the position of the valve body 200 is changed, the flow S of the working fluid changes, and the fluctuation of the fluid force makes the position of the valve body 200 unstable.
As described above, in the damping force control valve shown in Patent Document 1, the above-described several factors are related in a combined manner, making it difficult to control the position of the valve body 200 at the minute opening degree.

The problems described above do not occur in a damping force control valve provided with a stepping motor. This is because, when the position of the valve body is adjusted by the stepping motor, the valve body does not move even when receiving a fluid force, and therefore 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;
The valve body has a closed portion corresponding to the port when fully closed,
The port and the port are provided on the outer periphery of the valve body on the downstream side of 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 than the closed portion. A communication passage is formed to communicate with the first working fluid chamber.

According to the configuration of (1), the communication passage is formed on the outer periphery of the valve body on the downstream side of the closed portion corresponding to the port when fully closed. The valve body has, for example, a protrusion on the downstream side of the closed portion (seal portion), and a communication passage is formed on the outer periphery of the protrusion. Therefore, when the valve body moves from the fully closed position in the direction opposite to the downstream side, a part (protrusion) of the valve body is located in the port rather than immediately separating the valve body and the port. Condition occurs. In this state, the port and the first working fluid chamber are separated by a portion (protrusion) of the valve body, and the port and the first working fluid chamber are communicated by the communication passage. And when an opening degree is the largest, a valve body and a port will separate.

In short, in the conventional damping force control valve shown in FIG. 8, the valve body is always separated from the port when the flow path is open. On the other hand, in the configuration of (1), when the flow path is opened, first, a part of the valve body is in the state of being located in the port, and then the valve body is in the state of separating from the port. Thereby, it is possible to reduce the change in the area of the flow path of the working fluid with respect to the change in the position of the valve body at the minute opening degree. As a result, it is possible to suppress the control characteristic of the sharp damping force at the minute opening degree.

Describing from the relationship between the stroke of the valve body (the distance between the end face of the valve body and the port) and the pressure of the working fluid, when the flow rate is constant, the differential pressure before and after the valve is inversely proportional to the square of the opening area. In the conventional damping force control valve shown in FIG. 8, the opening area is proportional to the product of the diameter of the port and the stroke of the valve body, but the diameter of the port does not change. Thus, the differential pressure across the valve is inversely proportional to the square of the stroke of the valve body. Therefore, the change of the pressure of the working fluid with respect to the change of the stroke becomes large at the minute opening degree (that is, when the stroke is small). From the viewpoint of controllability, it is desirable that the relationship between the stroke of the valve body and the pressure of the working fluid be linear. According to the configuration of (1), the change in the area of the flow path of the working fluid with respect to the position change of the valve body at the small opening degree becomes small, so the relationship between the stroke of the valve body at the small opening degree and the pressure of the working fluid Can be approached linearly.

Furthermore, since the change in area of the flow path of the working fluid can be reduced, the change in speed of the flow S (see FIG. 8) of the working fluid can be mitigated. Therefore, the fluctuation of the fluid force can be suppressed, whereby the position of the valve can be stabilized. Therefore, the damping force control valve of (1) is excellent in the position controllability of the valve body at the time of the minute opening degree, and the range of the opening degree which can be accurately controlled is wide.

(2) The damping force control valve of (1),
It is preferable that the communication passage be arranged in a point-symmetrical manner with respect to the axis of the valve body as viewed in the axial direction of the valve body.

In the case where the communication passages are arranged point-symmetrically, 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 (2), the flow of the working fluid can be stabilized by intentionally making the communication passage point-symmetrical. 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.

(3) The damping force control valve according to (1) or (2), wherein
It is preferable that the communication passage is formed in a part of the outer periphery of the valve body.

In order to moderate the change in the area of the flow path of the working fluid with respect to the change in the stroke of the valve body, for example, it is conceivable to lengthen the portion (protrusion) downstream of the closed portion of the valve body. However, if the downstream portion is made longer, the entire valve body becomes longer. In addition, securing a long stroke makes it difficult to use a small solenoid. I would like to avoid that situation from the viewpoint of reducing the size and weight of the valve. Therefore, in order to investigate and improve the position controllability of the valve at the time of the minute opening, the inventor does not necessarily have to form a communication passage in the entire outer periphery of the valve, and a part of the outer periphery It has been found that, if the valve is formed in the above, it is possible to improve the position controllability of the valve at the time of the minute opening, and further to realize the downsizing and weight reduction of the valve.

According to the configuration of (3), it is possible to realize the improvement of the position controllability of the valve body at the minute opening degree, and the downsizing and weight reduction of the valve at a high level.

(4) The damping force control valve according to any one of (1) to (3), wherein
It is preferable that a taper is formed on the outer periphery on the downstream side of the valve body, and the thickness of the valve body becomes thinner toward the downstream side of the valve body.

The conventional damping force control valve shown in FIG. 8 is fully closed when the end face 200c of the valve body 200 is located on the same plane as the port 234b, so the valve body 200 does not enter the port 234b. However, in the present invention, a part of the valve body enters the port. Therefore, in the invention of (4), the outer periphery on the downstream side of the valve body is tapered, and the thickness of the valve body is made thinner as it approaches the downstream side of the valve body, so that the end face of the valve body can be more smoothly. Can be inserted into the port.

(5) The damping force control valve according to any one of (1) to (4), wherein
Preferably, the communication path establishes communication between the port and the first working fluid chamber when a portion of the valve downstream of the blocking portion is located in the port.

According to the configuration of (5), when the flow path is opened, first, a part of the valve body remains in the port, and then the valve body is separated from the port. When a portion of the valve body is located in the port, the port and the first working fluid chamber are separated by the communication passage when the port and the first working fluid chamber are separated by the portion (projecting portion) of the valve body And communicate with each other. Therefore, it is possible to reduce the change in the area of the flow path of the working fluid with respect to the change in the position of the valve body at the minute opening degree.

(6) A shock absorber,
The shock absorber preferably includes the damping force control valve according to any one of (1) to (5).

According to the configuration of (6), since the damping force control valve according to any one of (1) to (5) is provided, the range of damping force that can be accurately controlled is wide, and high responsiveness can be realized.

(7) The shock absorber of (6),
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 (7), in the damping force control valve, the working fluid can be flowed in the direction in which the position of the valve body is relatively stable. 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.

(A) is a longitudinal cross-sectional view which shows typically the damping force control valve which concerns on one Embodiment of this invention, (b) is the partial expanded sectional view. 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. (A) is a partial expanded side view which shows typically the downstream end of the valve body shown in FIG. 1, (b) is an A direction view of (a), (c) is (a) Is a view of the valve body shown in FIG. (A) is a partial expanded side view which shows typically the modification of the downstream end of a valve body, (b) is an A direction view of (a), (c) is (a) It is the figure which looked at the valve body shown to in the reverse direction U. FIG. (A) to (i) are side views schematically showing an example of the downstream end shape 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 (a) is a longitudinal cross-sectional view which shows typically the damping force control valve 10 which concerns on one Embodiment of this invention, (b) is the elements on larger scale sectional drawing.
FIG. 1 (a) shows a state when the damping force control valve 10 is fully closed, and FIG. 1 (b) shows a state when the minute opening degree.
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 prevented. 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 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. The valve head 26 has a bottomed cylindrical shape. 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 path of the working fluid from the working fluid path 32 to the working fluid path 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 tip shape of the valve body 20 will be described using FIG. 1 (b).
In the figure, reference numeral 50 denotes a closed portion corresponding to the first port 30a when fully closed (see FIG. 1). In other words, when the blocking portion 50 is present at the same position as the first port 30 a in the axial direction of the valve body 20, the damping force control valve 10 is in the closed state.

In the valve body 20, the protrusion 51 is located on the downstream direction D side of the closing portion 50. The end face 20a of the valve body 20 includes a flat portion 20d and an inclined portion 20e which is inclined in the opposite direction U from the flat portion 20d. The inclined portion 20 e faces in the outer peripheral direction. At the minute opening shown in FIG. 1B, a communication passage 52 for communicating the first port 30a with the first working fluid chamber 30 is formed on the outer periphery of the valve body 20 in the protrusion 51. Further, as shown in FIG. 1 (b), the communication passage 52 is formed in a part (approximately half in the figure) of the outer periphery of the valve body 20. As described above, the communication passage 52 is disposed in an astigmatic manner with respect to the axis C of the valve body 20 as viewed in the axial direction S of the valve body 20. That is, it is unevenly distributed in the outer periphery of the valve body 20 on the basis of the axis C of the valve body 20.

At the time of the minute opening shown in FIG. 1 (b), the projecting portion 51 located in the downstream direction D of the closing portion 50 is located in the first port 30a, while the communication passage 52 is the first port 30a and the first port 30a. It communicates with the working fluid chamber 30. As described above, in the damping force control valve 10, the first port 30a and the first working fluid chamber 30 communicate with each other through the communication passage 52 while a part of the protrusion 51 is positioned in the first port 30a. .

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.

About half of the end face 20a (see FIG. 1) of the valve body 20 is slanted. 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 (for example, about 0.5 mm), as shown in FIG. 2B, the flat portion 20 d and the first port 30 a It exists in 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. As a result, it is possible to widen the range of the precisely controllable opening degree while suppressing the control characteristic of the sharp damping force at the minute opening degree.

Fig.3 (a) is a partial expanded side view which shows typically the downstream end of the valve body shown in FIG. 1, (b) is an A direction view of (a), (c) is It is the figure which looked at the valve body shown to (a) in the reverse direction U. FIG.

As shown in FIG. 3, an outer peripheral tapered portion 20 f is formed on the valve body 20. In the axial direction S, the length of the outer peripheral tapered portion 20f is shorter than the length of the large diameter portion 21a.

The outer circumferential tapered portion 20 f is formed in the projecting portion 51. When the projecting portion 51 is positioned in the first port portion 30a (see FIG. 1), the first port portion 30a and the first working fluid chamber 30 communicate with each other in the outer peripheral tapered portion 20f. The outer circumferential tapered portion 20f constitutes a communication passage. In the outer circumferential tapered portion 20 f, the thickness of the valve body 20 becomes thinner as it approaches the downstream direction D, but does not become zero. Therefore, in the outer peripheral tapered portion 20 f, the first working fluid chamber 30 and the passage 21 of the valve body 20 do not directly communicate with each other.

The inclined portion 20e also constitutes the communication passage 52 (see FIG. 1B) as described above. In the inclined portion 20 e, the first working fluid chamber 30 and the first port 30 a communicate with each other, and the first working fluid chamber 30 and the passage 21 of the valve body 20 directly communicate with each other. As described above, the communication passage formed by the outer peripheral tapered portion 20f is different from the communication passage formed by the inclined portion 20e. The communication passage in the present invention preferably communicates the first working fluid chamber 30 with the first port 30 a and the passage 21. This is because the working fluid can flow more smoothly. In addition, although the angle which the outer periphery taper part 20f and the axial direction S comprise is not specifically limited, For example, it is preferable that it is 10 degrees or less.

Next, another embodiment of the present invention will be described with reference to FIG.
Fig.4 (a) is a partial expanded side view which shows typically the modification of the downstream end of a valve body, (b) is an A direction view of (a), (c) is It is the figure which looked at the valve body shown to a) in the reverse direction U. FIG.

The valve body 20 shown in FIG. 4 is the same as the valve body shown in FIG. 3 except for the shape of the large diameter portion 21a. In FIG. 4, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof will be omitted or simplified.

The large diameter portion 21a shown in FIG. 4 has a cylindrical space. Even with the valve body 20 shown in FIG. 4, the working fluid flowing in from the communication passage flows like the flow X of the working fluid shown in FIG. 2 (b), similarly to the valve body 20 shown in FIGS. .

5 (a) to 5 (i) are longitudinal cross-sectional views schematically showing examples of the downstream side end shape 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. In addition, an outer peripheral tapered portion 20f is formed on the outer peripheral edge of the end face 20a. A communication passage is formed by the outer peripheral tapered portion 20f.

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. In addition, an outer peripheral tapered portion 20f is formed on the outer peripheral edge of the end face 20a. A communication passage is formed by the outer peripheral tapered portion 20f.

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. A communication passage is formed by the outer peripheral tapered portion 20f.

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. A communication passage is formed by the outer peripheral tapered portion 20f.

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. A communication passage is formed by the outer peripheral tapered portion 20f.

FIG.5 (f) has shown the valve body of FIG. 3 and the same shape. 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. A communication path is formed by the inclined portion 20e and the outer peripheral tapered portion 20f.

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. A communication path is formed by the inclined portion 20e and the outer peripheral tapered portion 20f.

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. A communication passage is formed between the inclined portion 20e and the outer peripheral tapered portion 20f.

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). A communication passage is formed between the inclined portion 20e and the outer peripheral tapered portion 20f.

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. A communication passage is formed between the inclined portion 20e and the outer peripheral tapered portion 20f. As shown in FIG. 5, in the present invention, it is preferable to have an inclined portion 20 e formed on a part of the end face 20 a of the valve body 20, and the inclined portion 20 e is facing the outside of the valve body 20 in the radial direction. . This is because the change in the opening area of the communication passage due to the stroke of the valve body 20 can be reduced when the opening degree is relatively small.

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 a plurality of shims damping valves 148 damping

valves

148, 150. 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).

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, the damping force control valve 10 causes the working fluid to flow from the working fluid passage 32 to the working fluid passage 31 via the first working fluid chamber 30. Can. 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, in the damping force control valve 10, a communication passage for connecting the first port 30a and the first working fluid chamber 30 is formed on the outer periphery of the projecting portion 51 of the valve body 20. Specifically, the communication passage is formed by the inclined portion 20e and the outer peripheral tapered portion 20f. Therefore, when the valve body 20 moves in the opposite direction U from the state in which the first port 30 a is closed by the closing portion 50, the protrusion 51 is first positioned in the first port 50. Then, the valve body 20 is separated from the first port 30a. Accordingly, it is possible to reduce the change in the area of the flow path of the working fluid with respect to the change in the position of the valve body 20 at the minute opening degree. As a result, it is possible to suppress the control characteristic of the sharp damping force at the minute opening degree, and to make the relationship between the stroke of the valve body at the minute opening degree and the pressure of the working fluid close to linear. Furthermore, since the change in area of the working fluid flow path can be reduced, the change in velocity of the working fluid flow X can be mitigated. Therefore, the fluctuation of the fluid force can be suppressed, whereby the position of the valve can be stabilized.

Further, in the damping force control valve 10, the communication passage 52 is disposed in a point-symmetrical manner with respect to the axis C of the valve body 20, so that the flow of the working fluid can be stabilized. Thereby, the fluctuation of the fluid force can be suppressed, and as a result, the stability and accuracy of position control of the valve body in the axial direction can be improved.

Further, in the damping force control valve 10, since the communication passage 52 is formed in a part of the outer periphery of the valve body 20, improvement of the position controllability of the valve body 20 at the minute opening degree, downsizing of the valve It is possible to realize weight reduction at a high level.

In addition, when the valve body 20 includes the outer peripheral tapered portion 20f and the thickness of the valve body 20 becomes thinner toward the downstream direction D side of the valve body 20, the end face 20a of the valve body 20 can be made more smoothly. It can be inserted into port 30a.

Furthermore, when the protrusion 51 is located in the first port 30a, the communication path 52 establishes communication between the first port 30a and the first working fluid chamber 30. Therefore, when the flow path of the damping force control valve 10 opens from the closed state, first, a part of the valve body 20 remains in the first port 30a, and then the valve body 20 is moved from the first port 30a. It will be away. In the state where the protrusion 51 is located in the first port 20, as shown in FIG. 1B, when the first port 30a and the first working fluid chamber 30 are divided by the protrusion 51, The passage 52 allows the first port 30a and the first working fluid chamber 30 to communicate with each other. Therefore, it is possible to reduce the change in the area of the flow path of the working fluid with respect to the change in the position of the valve body 20 at the minute opening degree.

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, preferably, the working fluid can be made 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, the entire end face 20 a of the valve body 20 may be inclined with respect to the axial direction S. 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 communicating portion 23 solenoid coil 26 valve bed 30 first working fluid chamber 30a first port 40 second working fluid chamber 50 closing portion 51 projecting portion 52 communicating path

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;
The valve body has a closed portion corresponding to the port when fully closed,
The port and the port are provided on the outer periphery of the valve body on the downstream side of 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 than the closed portion. A communication passage is formed to communicate with the first working fluid chamber.
The damping force control valve according to claim 1, wherein
The communication passage is disposed in an astigmatic manner with respect to the axis of the valve as viewed from the axial direction of the valve.
The damping force control valve according to claim 1 or 2, wherein
The communication passage is formed at a part of the outer periphery of the valve body.
The damping force control valve according to any one of claims 1 to 3, wherein
A taper is formed on the outer periphery on the tip side of the valve body, and the thickness of the valve body becomes thinner toward the downstream side of the valve body.
The damping force control valve according to any one of claims 1 to 4, wherein
The communication path establishes communication between the port and the first working fluid chamber when a portion of the valve downstream of the blocking portion is located in the port.
A shock absorber,
The shock absorber is provided with the damping force control valve according to any one of claims 1 to 5.
The shock absorber according to claim 6, wherein
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.