JP2013170600A - Damping force control valve and shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damping force control valve having superior position controllability of a valve element during a minute opening thereof, and having a wide range of a controllable opening with high accuracy.SOLUTION: A damping force control valve comprises a hollow, cylindrical valve element reciprocally moved by a solenoid; a first hydraulic fluid chamber comprising a guide hole with the valve element being inserted therein, and a port formed at the position facing an end face of the valve element; and a second hydraulic fluid chamber in communication with the first hydraulic fluid chamber via a passage in the valve element. A gap between the end face of the valve element and the port forms a flow path through which the hydraulic fluid passes, and the degree of opening of the flow path is changed according to the position of the end face of the valve element. The damping force is controlled thereby, and when the degree of opening of the flow path is minimum, the gap between the valve element and the port is totally closed, and when the degree of opening of the flow path is maximum, the valve element is separated from the port. In the passage in the valve element, the opening area of a downstream side end in the flow direction in which the hydraulic fluid in the first hydraulic fluid chamber is discharged outside the first hydraulic fluid chamber via the port is larger than the opening area of a minimum diameter part in the passage.

Description

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

  In general, automobiles, motorcycles, and the like are provided with shock absorbers (buffers) to attenuate vibrations generated in the vehicles. The shock absorber usually includes a cylinder, and a piston and a support shaft that supports the piston are provided in the cylinder. The cylinder is separated into two oil chambers by a piston, and the piston moves in accordance with the expansion and contraction of the shock absorber, whereby the oil moves between the two oil chambers. The oil movement path is provided with orifices, valves, etc. having a relatively small flow path area, and a damping force is generated by the fluid resistance when passing through the flow path with a narrow area, which 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 can be adjusted by electronic control. As such a shock absorber, there are a shock absorber in which a valve is installed in a cylinder and a shock absorber in which a valve is installed outside the cylinder. The damping force can be controlled by adjusting the opening degree.

  As a conventional damping force control valve, for example, there is 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 a stepping motor to change the opening of the valve. Therefore, the position change of the valve body due to the fluid force hardly occurs, and the position control of the valve body can be performed relatively accurately. On the other hand, in the stepping motor, the rotation angle is changed by integrating pulses, and the rectilinear speed of the valve body is determined by the pitch of the screw that converts the rotary motion into the linear motion. Since it is necessary to make the valve body stationary against the hydraulic pressure, the pitch of the screws cannot 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 cannot be obtained.

  The advantage of damping force control by electronic control is that the damping force can be adjusted according to the driving conditions, but if the excellent responsiveness cannot be obtained as described above, the damping force can be accurately adjusted according to the driving conditions. It is difficult to adjust well, and the merit of electronic damping control cannot 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 that linearly reciprocates by a solenoid is formed in the first working fluid chamber 234. The guide hole 234c is inserted. The first working fluid chamber 234 communicates with a second working fluid chamber (not shown) via the passage 200e of the valve body 200. The second working fluid chamber corresponds to the oil chamber 112 in Patent Document 1. The first working fluid chamber 234 is provided with a port 234b at a position facing the end surface 200c of the valve body 200. A gap between the end surface 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 depending on the position of the end surface 200c of the valve body 200, and thereby 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 response cannot be obtained when a stepping motor is used.

International Publication No. 2011/078317 Pamphlet

  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 element and the opening) has a very small 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 with respect to the position controllability of the valve body 200 at a minute opening.

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

The inventor has studied the above-described problems and has obtained the following knowledge.
As shown in FIG. 8, when the distance between the end surface 200c of the valve body 200 and the port 234b (working fluid flow path) is narrow, a force is applied to the vehicle to expand and contract the suspension, and the working fluid becomes the first working fluid chamber 234. When the fluid is discharged from the first working fluid chamber 234 through the interval, the flow S of the working fluid becomes faster because the interval is narrow.

  The flow S of the working fluid enters the working fluid path 232 through between the periphery of the end surface 200c of the valve body 200 and the periphery of the port 234b. The flow S of the working fluid at this time is directed from the outer peripheral side of the valve body 200 toward the center side while moving toward the downstream side along the axial direction of the valve body 200. Therefore, the flow S of the working fluid from the entire periphery collides with each other. As a result, a flow F of the working fluid going to the downstream side and a flow R going in the opposite direction to the flow F are generated.

  The flow F of the working fluid is a rapid flow that passes through the working fluid path 232 and goes out of the damping path control valve. Therefore, the pressure in the working fluid path 232 is lowered. Further, the pressure in the passage 200e increases due to the generation of the flow R of the working fluid, and the pressure propagates to the second working fluid chamber (corresponding to the second working fluid chamber 40 in Patent Document 1), whereby the second The pressure in the working fluid chamber increases. When such working fluid flows F and R are generated, a pressure difference is generated between the passage 200e side and the working fluid path 232 side. Due to this pressure difference, a force directed to the port 234b is applied to the valve body 200.

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

In this manner, when the force toward the port 234b is applied to the valve body 200, the valve body 200 approaches the port 234b, and the interval (the working fluid flow path) between the end surface 200c of the valve body 200 and the port 234b is further narrowed. . As the distance between the end surface 200c of the valve body 200 and the port 234b is narrower, the force applied to the valve body 200 becomes stronger, so that the position of the valve body 200 further changes.
By such a mechanism, the case where the valve body 200 was not stabilized at the target position occurred.

The above-described problem does not occur in the damping force control valve provided with the 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 if it receives a fluid force, and therefore the position of the valve body does not change due to the flow of the working fluid.
The above knowledge is a mechanism for generating a problem peculiar to a damping force control valve provided with a solenoid, and the present inventor has obtained the above knowledge and completed the present invention based on the above knowledge.

That is, the present invention employs the following configuration.
(1) A damping force control valve,
The damping force control valve is
A hollow cylindrical valve body that linearly reciprocates by a solenoid;
A first working fluid chamber comprising 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 communicating with the first working fluid chamber via a passage in the valve body;
With
The gap between the end face of the valve body and the port is a flow path through which a working fluid passes,
The opening degree of the flow path is changed depending on the position of the end face of the valve body, whereby the damping force is controlled,
When the opening of the flow path is the minimum, the gap between the valve body and the port is fully closed, while when the opening of the flow path is the maximum, the valve body is away from the port,
In the passage in the valve body, the opening area at the downstream end in 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 in the passage. It is larger than the opening area of the small diameter part.

  According to the structure of (1), the opening area of a downstream end is larger than the opening area of the minimum diameter part in a channel | path. As a result, a space having a larger opening area than the minimum diameter portion is secured on the downstream side of the passage. Therefore, even if the flow R (see FIG. 8) of the working fluid from the downstream to the second working fluid chamber is generated via the passage, the working fluid flow R is a space having a wide opening area on the downstream side of the minimum diameter portion. It is easy to return to the flow F of the working fluid while vortexing inside and diffusing. As a result, an increase in pressure in the second working fluid chamber can be suppressed, so that an increase in the pressure difference between the downstream side and the passage is prevented, and a force applied to the valve body toward the port can be suppressed. .

  Moreover, since the opening area of the downstream end is large, the distance that the flow S (see FIG. 8) of the working fluid passing between the end face of the valve element and the port flows along the surface of the end face of the valve element is small. Relatively short. Therefore, it is difficult for the working fluid on the surface of the end face of the valve body to be drawn to the flow S of the working fluid. Therefore, the pressure drop on the surface of the end face of the valve body is prevented, and the force applied to the valve body toward the port can be suppressed. Therefore, according to the configuration of (1), it is excellent in the position controllability of the valve body at the time of a minute opening, a wide range of opening that can be controlled with high accuracy, and high responsiveness can be realized.

(2) The damping force control valve according to (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 applies force to the valve body along the axial direction of the valve body,
In the passage in the valve body, it is preferable that an opening area of the downstream end is smaller than an inner diameter area of the biasing body.

  According to the structure of (2), the opening area of the said downstream end is smaller than the internal diameter area of the cyclic | annular biasing body which applies force to a valve body along the axial direction of a valve body, Is inserted, it is not necessary to install the urging body in the passage from the first working fluid chamber to the second working fluid chamber via the passage. Therefore, the pressure transmission in the passage or the movement of the working fluid during 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),
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 large-diameter portion toward the second working fluid chamber. It is preferable that it is larger than the diameter of the part.

  According to the configuration of (3), the flow R of the working fluid easily returns to the flow F of the working fluid while diffusing in a vortex in the large-diameter portion having a diameter larger than the diameter of the communication portion. Further, the working fluid flow S (see FIG. 8) passing between the end face of the valve body and the port has a short distance along the surface of the end face of the valve body, and the force applied to the valve body toward the port is suppressed. can do. Therefore, according to the configuration of (3), the position controllability of the valve body at the minute opening is further excellent, the range of the opening that can be controlled with high accuracy is further widened, and higher responsiveness can be realized.

(4) The damping force control valve according to (3),
The large diameter portion preferably has a step where the diameter of the passage changes.

  According to the structure of (4), since it becomes easy to produce | generate a vortex within a large diameter part, the raise of the pressure of a 2nd working fluid chamber can be suppressed effectively.

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

  According to the structure of (5), since it becomes easy to produce | generate a vortex within a large diameter part, the raise of the pressure of a 2nd working fluid chamber can be suppressed effectively.

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

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, there is a minute gap between the valve body and the bearing, so it is difficult to stabilize the valve body on the axis. Therefore, the flow of the working fluid fluctuates, and as a result, the flow may become unstable.
On the other hand, according to the configuration of (6), the centroid position of the large-diameter portion and the centroid position of the valve body are different from each other, thereby suppressing the temporal change in the flow of the working fluid and reducing the flow of the working fluid. It can be stabilized. Thereby, the position of the valve body in the radial direction can be stabilized, and the fluctuation of the fluid force can be suppressed. As a result, the stability and accuracy of the 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),
It is preferable that substantially only fluid is present in the passage of the valve body.
The “fluid” here is not limited to a working fluid but includes a gas such as air. Further, “substantially only the fluid exists” means that the fluid may contain solid impurities that move with the working fluid. Examples of such solid impurities include dust generated from a sliding portion in a valve (or shock absorber).

  According to the structure of (7), the biasing body etc. are not attached in a channel | path, the movement of the working fluid in a channel | path at the time of movement of a valve body is smooth, and it can improve responsiveness more. .

(8) The damping force control valve according to any one of (1) to (7),
The direction of the flow of the working fluid in the first working fluid chamber being discharged out of the first working fluid chamber through the port is preferably along the axial direction of the valve body.

  According to the structure of (8), since a working fluid can be discharged | emitted smoothly out of a 1st working fluid chamber, responsiveness can further be improved.

(9) A shock absorber,
The shock absorber preferably includes the 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 controlled with high accuracy is wide, and high responsiveness can be realized.

(10) The shock absorber according to (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 out of the first working fluid chamber through the port in the damping force control valve. Is preferred.

  According to the configuration of (10), in the damping force control valve, it is possible to flow the working fluid in a direction that can more effectively suppress the force applied to the valve body toward the port. Therefore, the range of damping force that can be controlled with high accuracy 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.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in the position controllability of the valve body at the time of a very small opening degree, and can provide the damping force control valve with the wide opening range which can be controlled accurately.

It is a longitudinal section showing typically a damping force control valve concerning one embodiment of the present invention. It is a longitudinal cross-sectional view which shows typically the mode at the time of the fully closed (a) of the damping force control valve shown in FIG. It is a longitudinal cross-sectional view which shows typically the mode at the time of the fully closed (a), the minute opening degree (b), and the fully closed time (c) 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)-(i) is a side view which shows typically the modification of the shape of the downstream end of a valve body. It is a hydraulic circuit diagram which shows an example of the shock absorber provided with the damping force control valve shown in FIG. It is a hydraulic circuit diagram 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 at the time of a very small opening degree.

Embodiments of the present invention will be described below 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 where the damping force control valve 10 is fully closed.
In the following description, the direction in which the working fluid in the first working fluid chamber 30 is discharged through the first port 30a is referred to as a downstream direction D. 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 11a on the downstream direction D side and an opening 11b on the opposite direction U side. The inner cylinder 12 is fitted into the opening 11 b of the outer cylinder 11. The opposite end U side end of the outer cylinder 11 is bent inward and is in contact with 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 protrudes in an annular shape 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 the inner edge portion thereof. A cylindrical guide member 13 is inserted into the cylindrical portion 11d. The guide member 13 has a flange portion 13a on the downstream direction D side. The flange portions 11c and 13a are in contact with each other. This restricts the movement of the guide member 13 in the opposite direction U in the outer cylinder 11. The guide member 13 includes 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 surface 20a on the downstream direction D side and an end surface 20b on the opposite direction U side. The valve body 20 has a passage 21 extending from the end surface 20a to the end surface 20b. The passage 21 includes a large diameter portion 21a including an end surface 20a on the downstream direction D side, and a communication portion 21b extending from the end on the U direction opposite to the large diameter portion 21a toward the second working fluid chamber 40. The communicating part 21b is a columnar space and has a substantially constant diameter. The opening area of the passage 21 (large diameter portion 21a) on the end surface 20a on the downstream direction D side of the valve body 20 is larger than the opening area of the communication portion 21b. In the passage 21, the communication portion 21b has the smallest diameter. That is, in the damping force control valve 10, the communication portion 21 b is the smallest diameter portion in the passage 21. A 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.

  An end surface 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 contact 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 side U of the cylindrical portion 11d. The support member 14 faces the cylindrical portion 11d on the same axis as the cylindrical portion 11d. The support member 14 includes 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 projecting in an annular shape 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 in the bearing 20c, and the bearing 20c supports the valve body 20 so that sliding is possible. On the inner peripheral surface of the support member 14, a spring receiving member 15 is fixed closer to the opening 14 b than the guide portion 14 c. An annular seal 16 (for example, 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 end U side of the support member 14. The cap 17 closes the opening 14b. 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 surface 20 b of the valve body 20 and the spring receiving member 15. The coil spring 18 urges the valve body 20 in the downstream direction D. A cylindrical tube member 19 is provided so as to connect the cylindrical portion 11d and the support member 14. The cylindrical member 19 is made of a nonmagnetic material. A bobbin 22 is provided in the outer cylinder 11. 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. 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, the plunger 25 can be moved in the axial direction S between the guide member 13 and the guide portion 14 c by adjusting the magnetic flux density of the magnetic field generated by the solenoid coil 23. 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 25a of the plunger 25 is formed by the cylindrical portion 11d, the guide member 13, the guide portion 14c, and the cylindrical member 19. The working space HO is also filled in the installation space 25a. The space 25 a communicates with the first working fluid chamber 30 through a gap between the outer peripheral surface of the valve body 20 and the inner peripheral surface of the guide member 13. The space 25a communicates with the second working fluid chamber 40 via a gap between the outer peripheral surface of the valve body 20 and the inner peripheral surface of the guide portion 14c.

  In the outer cylinder 11, a bottomed substantially cylindrical valve head 26 is installed on the opening 11 a side 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 surface 20 a of the valve body 20. In the valve head 26, the working fluid path 31 extends in the downstream direction D from the first port 30a. The valve head 26 includes 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 path 32 extends from the second port 30b in the radial direction.

  A first working fluid chamber 30 is constituted by the valve head 26 and the guide member 13. The first working fluid chamber 30 includes a guide hole 13b. The first working fluid chamber 30 and the second working fluid chamber 40 are disposed to face each other with the valve body 20 in between. The end surface 20a 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 communicate with each other 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 into the first working fluid chamber 30 from the working fluid path 32 along the radial direction of the valve body 20.

  In the first working fluid chamber 30, the downstream side surface 13 c of the guide member 13 and the bottom surface 26 a of the valve head 26 face each other along 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. The fixture is not limited to a circlip.

  On the downstream direction D side of the circlip 33, a coil spring 34 as an urging member is installed between the circlip 33 and the bottom surface 26 a of the valve head 26. The valve body 20 is inserted through the coil spring 34. As it approaches the downstream direction D, the diameter of the coil spring 34 increases. Therefore, the flow of the working fluid from the working fluid path 32 through the first working fluid chamber 30 to the working fluid path 31 is hardly disturbed by the coil spring 34.

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

  The coil springs 18, 34, and 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. The urging body is not limited to a coil spring, and for example, a conventionally known urging body such as a leaf spring can be adopted.

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 state of the damping force control valve shown in FIG. 1 when fully closed (a), when the opening degree is minute (b), and when fully opened (c).

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

  Slant processing is applied to a part (substantially half) of the end face 20a (see FIG. 1) of the valve body 20. Thereby, the end surface 20a includes a flat portion 20d and an inclined portion 20e inclined from the flat portion 20d toward the opposite direction D. In FIG. 2A, the flat portion 20 d is located on the downstream direction D side from the first port 30 a and enters the working fluid path 31. An end edge on the opposite direction U side of the inclined portion 20 e exists 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 small opening (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 a gap between the inclined portion 20e and the first port 30a. This interval is the working fluid flow path T. When the opening is very small, the flow path T of the working fluid is narrow, so 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 path 31, and a part of the flow X goes in the downstream direction D as it is. Further, a part of the flow X becomes a flow Y directed in the opposite direction U. Since the large-diameter portion 21a is formed at the downstream side D side end of the valve body 20, the flow Y of the working fluid forms a vortex in the large-diameter portion 21a and diffuses into the flow X of the working fluid. 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, increase of the pressure difference of the working fluid path 31 and the 2nd working fluid chamber 40 is prevented, and the force added to the valve body 20 toward the 1st port 30a can be suppressed. Further, since the large-diameter portion 21a is formed, the distance that the working fluid flow X flows along the end surface 20a (the inclined portion 20e) is short. Therefore, the force applied to the valve body 20 toward the first port 30a can be suppressed. Thereby, the damping force control valve 10 is excellent in the position controllability of the valve body 20 at the time of a very small opening, has a wide range of opening that can be controlled with high accuracy, and can realize higher responsiveness.

  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 This is the distance from a part of the outer peripheral edge of one port 30a. Therefore, the change in the opening area of the flow path T with respect to the stroke of the valve body 20 (the displacement amount in the axial direction S) is relatively small.

  When the solenoid coil 23 is energized and the opening degree of the damping force control valve 10 is adjusted to the maximum (for example, an interval of about 2 mm), as shown in FIG. Leave. When the valve body 20 and the first port 30a are separated, the flow path T is the 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 of the opening area of the flow path T with respect to the stroke of the valve body 20 is relatively large.

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

Next, another embodiment of the present invention will be described.
FIG. 3 is a longitudinal cross-sectional view schematically showing the state of the damping force control valve according to another embodiment of the present invention when it is fully closed (a), when it is slightly opened (b), and when it is fully closed (c). is there. Since FIG. 3 is the same as FIG. 2 except for the shape of the downstream end D side of the valve body 20, in FIG. 3, the same reference numerals are given to the same configurations as FIG. The description is omitted or simplified.

  In the damping force control valve 10 shown in FIG. 3, the end face 20a ′ 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 30 a is closed. The end surface 20 a ′ of the valve body 20 exists 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 small opening, as shown in FIG. 3B, the end face 20a of the valve body 20 (FIG. 3A) and the first port 30a opens. A distance between the entire outer peripheral edge of the valve body 20 and the entire outer peripheral edge of the first port 30a is a flow path T of the working fluid. When the opening is very small, the flow path T of the working fluid is narrow, so 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 goes in the downstream direction D as it is. Further, a part of the flow X becomes a flow Y directed in the opposite direction U. Since the large-diameter portion 21a is formed at the downstream side D side end of the valve body 20, the flow Y of the working fluid forms a vortex in the large-diameter portion 21a and diffuses into the flow X of the working fluid. Easy to return. Thereby, increase of the pressure difference of the working fluid path 31 and the 2nd working fluid chamber 40 is prevented, and the force added to the valve body 20 toward the 1st port 30a can be suppressed. Further, since the large diameter portion 21a is formed, the distance that the working fluid flow X flows along the end face 20a is short. Therefore, the force applied to the valve body 20 toward the first port 30a can be suppressed. Thereby, the damping force control valve 10 is excellent in the position controllability of the valve body 20 at the time of a very small opening, has a wide range of opening that can be controlled with high accuracy, and can realize higher responsiveness. Thereafter, when the opening degree of the damping force control valve 10 is adjusted to the maximum, as shown in FIG.

Next, a modified example 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.
4A to 4H are longitudinal sectional views schematically showing an example of the shape of the downstream end of the valve body 20.
In the figure, Q is the radius of the communication 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 in 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 part 21b. 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. This dimensional relationship between Q, V, and W is an example of this embodiment, and the dimensional relationship between Q, V, and 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, and H> W.

  In FIG.4 (b), the large diameter part 21a is cylindrical, and there exists a level | step difference between the large diameter part 21a and the communication part 21b. The depth H satisfies H> Q, H> V, and H> W.

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

  In FIG.4 (d), the large diameter part 21a consists of the cylindrical part located in the downstream direction D side, and the taper-shaped part located in 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. The depth K satisfies K> Q, K> V, K> W, and K> J. J and W satisfy W> J. When viewed from the downstream direction D side of the valve body 20, the 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.4 (e), the large diameter part 21a consists of the cylindrical part located in the downstream direction D side, and the taper-shaped part located in 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 part 21a is a taper shape. The depth K satisfies K> Q, K> V, and K> W. When viewed from the downstream direction D side of the valve body 20, the 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 part 21a is a taper shape. The depth K satisfies K> Q, K <V, and K> W. When viewed from the downstream direction D side of the valve body 20, the 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 part 21a is a taper shape. The depth K satisfies K <Q, K <V, K> W. When viewed from the downstream direction D side of the valve body 20, the 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. 4A to 4H, the flow Y of the working fluid toward the opposite direction U is large as shown in FIGS. 2B and 3B. It returns to the flow X of the working fluid in the downstream direction D while vortexing and diffusing 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. The angle formed by the axial direction S of the valve body 20 and the tapered portion of the large diameter portion 21a is not particularly limited, but is preferably 22.5 ° or more, for example.

  Fig.5 (a)-(i) is a side view which shows typically the modification of the shape of the downstream end of a valve body.

  In FIG. 5A, a cylindrical large-diameter portion 21a is formed so as to include the end surface 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 communication part. The axis C of the valve body 20 is different from the axis C ′ of the large diameter portion 21a. That is, the position of the center of gravity of the large diameter portion 21a and the position of the center of gravity of the valve body 20 are different. Further, an outer peripheral taper portion 20f is formed on the outer peripheral edge of the end surface 20a.

  In FIG.5 (b), the large diameter part 21a is formed so that the end surface 20a of the downstream direction D side of the valve body 20 may be included. 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 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, an outer peripheral tapered portion 20f is formed on the outer peripheral edge of the end surface 20a.

  In FIG.5 (c), the large diameter part 21a is formed so that the end surface 20a of the downstream direction D side of the valve body 20 may be included. 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 surface 20a.

  In FIG. 5D, a cylindrical large diameter portion 21 a is formed so as to include the end surface 20 a on the downstream direction D side of the valve body 20. The axes of the valve body 20 and the large diameter portion 21a are matched. Further, an outer peripheral taper portion 20f is formed on the outer peripheral side of the end surface 20a.

  In FIG.5 (e), the large diameter part 21a is formed so that the end surface 20a of the downstream direction D side of the valve body 20 may be included. The large diameter portion 21a includes a cylindrical portion located on the downstream direction D side and a tapered portion located on the opposite direction U side. The axis of the valve body 20, the cylindrical portion, and the tapered portion The axis is common. Further, an outer peripheral taper portion 20f is formed on the outer peripheral side of the end surface 20a.

5 (f) has the same shape as the valve body 20 shown in FIGS. 1 and 2, but FIG. 5 (f) shows an outer peripheral taper 20f that was not shown in FIGS. ing.
In FIG. 5 (f), a 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 surface 20a. Further, slant processing is performed on substantially half of the end surface 20a of the valve body 20, and the end surface 20a includes a flat portion 20d and an inclined portion 20e that inclines in the opposite direction D from the flat portion 20d. The inclined portion 20e is flat.

  5 (g) is the same as FIG. 5 (d), except that the end surface 20a is slanted as in FIG. 5 (f).

  The valve body 20 of FIG. 5 (h) is the same as FIG. 5 (e) except that the end surface 20a is slanted as in FIG. 5 (f).

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

  The valve body 20 in FIG. 5 (j) is the same as FIG. 5 (f) except that the axis C of the valve body 20 and the axis C ′ of the tapered large diameter portion 21a are misaligned. The angle formed by the outer peripheral tapered portion 20f and the axial direction S of the valve body 20 is not particularly limited, but is preferably 10 ° or less, for example.

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

  The shock absorber 100 includes a hydraulic cylinder 112. A piston assembly 144 is installed in the hydraulic cylinder 112. The hydraulic cylinder 112 is divided into two working fluid chambers 158 and 160 by the 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 and 150 made up 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, and at this time, a damping force is generated (elongation damping). The working fluid cannot 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, and at this time, a damping force is generated (contraction damping). The working fluid cannot flow in the opposite direction.

  A damping force adjusting device 116 is installed between the working fluid chamber 158 and the reservoir tank 114. In the damping force adjusting 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 116b can flow the working fluid from the hydraulic cylinder 112 side to the reservoir tank 114 side, and cannot flow the working fluid in the opposite direction. The check valve 116c can flow the working fluid from the reservoir tank 114 side to the hydraulic cylinder 112 side. The working fluid cannot flow in the opposite direction. The reservoir tank 114 contains the working fluid O and the gas G, and the working fluid O and the gas G are in contact with each other at the interface OS. The working fluid O is, for example, working oil. 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 passes the working fluid from the working fluid path 32 through the first working fluid chamber 30. It can flow in the direction toward the working fluid path 31. The damping force control valve 10 can also flow the working fluid in the opposite direction. Moreover, the damping force control valve 10 is installed as a bypass with respect to the damping valve 116b, as shown in FIG.6 and FIG.7.

  When the piston assembly 144 moves in the X1 direction, the working fluid corresponding to the volume of the piston rod 162 that has entered the hydraulic cylinder 112 is discharged from the hydraulic cylinder 112 and moved 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 inside the 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 flow rate ratio between the damping valve 116b 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 is adjusted. The damping force is adjusted. Further, the working fluid also flows from the working fluid chamber 158 to the working fluid chamber 160 in the damping valve 150 of the piston assembly 144, the resistance at that time acts on the piston assembly 144, and the compression damping force (2) acts on the piston rod 162. 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 has retracted passes through the check valve 116c without resistance and returns to the hydraulic cylinder 112.
Thus, in the shock absorber 100, a part of the damping force at the time of compression can be adjusted by the damping force control valve 10. Specifically, the shock absorber 100 adjusts the compression damping force (1) generated by the entry of the piston rod 162 out of the damping force during compression (that is, the compression damping forces (1) and (2)). can do.
The present invention is not limited to this example. For example, the shock absorber 100 may be capable of adjusting all of the damping force during compression by the damping force control valve 10. Specifically, in the example illustrated in FIGS. 6 and 7, a check valve that allows the working fluid to flow from the working fluid chamber 158 to the working fluid chamber 160 may be provided instead of the damping valve 150. In the shock absorber 100 configured as described above, when the piston assembly 144 moves in the X1 direction, the compression damping force (1) is generated, but the compression damping force (2) is not generated. Therefore, by adjusting the compression damping force (1), it is possible to adjust the entire damping force during compression.

  As described above, according to the damping force control valve 10, the opening area of the downstream direction D side end in the passage 21 of the valve body 20 is larger than the opening area of the communication portion 21 b as the minimum diameter portion in the passage 21. Therefore, an increase in the pressure difference between the downstream working fluid passage 31 and the passage 21 is suppressed, and the force applied to the valve body 20 toward the first port 30a can be suppressed. Further, the distance X of the working fluid flow X passing between the end surface 20a of the valve body 20 and the first port 30a flows along the surface of the end surface 20a of the valve body 20 is relatively short. A 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 minute opening is excellent, the range of the opening that can be accurately controlled is wide, and high responsiveness can be realized.

  Further, the damping force control valve 10 includes coil springs 34 and 35 through which the valve body 20 is inserted in the first working fluid chamber 30 and applies 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 at the downstream end is smaller than the inner diameter area of the coil springs 34 and 35. The pressure transmission in the passage 21 or the movement of the working fluid during the movement of the valve body 20 is smooth, and the responsiveness can be further improved.

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

  In the valve body 20 shown to Fig.4 (a), the level | step difference from which the diameter of the channel | path 21 changes is provided between the large diameter part 21a and the communication part 21b. Thus, it is preferable that the large diameter part 21a has a level | step difference. Generation of vortices 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 end in the downstream direction D. Thus, it is preferable that the large diameter part 21a has a taper shape. Generation of vortices in the large diameter portion 21a is facilitated.

  In the valve body 20 shown in FIG. 5A, the axial center C ′ of the large diameter portion 21 a and the axial center C of the valve body 20 are different in the axial direction S view of the valve body 20. That is, the position of the center of gravity of the large diameter portion 21a is different from the position of the center of gravity of the valve body 20. The force applied 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 fluid exists in the passage 21 of the valve body 20. A member such as a biasing member is not attached in the passage 21. When the valve body 20 moves, the pressure transmission in the passage 21 or the movement of the working fluid is smooth.

  In the damping force control valve 10, the direction of the flow 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.

  In the above-described embodiment, the case where the damping force control valve 10 is connected to the hydraulic cylinder 112 has been described, but the arrangement method of the damping force adjusting device is not limited to the above example. 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, but the present invention is not limited to this example. In the present invention, it is preferable that the working fluid is configured to flow in a direction in which the working fluid is discharged from at least the first working fluid chamber 30 through the first port 30a. Further, the shock absorber 100 may be configured to flow the working fluid from the first working fluid chamber 30 through the first port 30a when extended, and the first working fluid chamber when degenerated. The working fluid may be configured to flow in a direction in which the working fluid is discharged from 30 through the first port 30a.

  In the above-described embodiment, the cylindrical valve body has been described, but the shape of the valve body is not limited to the above example. For example, the valve body may have a hollow rectangular tube shape. Further, the shape of the working fluid path is not limited to the above example, and the cross section of the working fluid path may be polygonal or elliptical. 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 for example, an ON / OFF solenoid may be used as the solenoid.

  Although the preferred embodiment of the present invention has 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 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 (10)

A damping force control valve,
The damping force control valve is
A hollow cylindrical valve body that linearly reciprocates by a solenoid;
A first working fluid chamber comprising 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 communicating with the first working fluid chamber via a passage in the valve body;
With
The gap between the end face of the valve body and the port is a flow path through which a working fluid passes,
The opening degree of the flow path is changed depending on the position of the end face of the valve body, whereby the damping force is controlled,
When the opening of the flow path is the minimum, the gap between the valve body and the port is fully closed, while when the opening of the flow path is the maximum, the valve body is away from the port,
In the passage in the valve body, the opening area at the downstream end in 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 in the passage. It is larger than the opening area of the small diameter part. The damping force control valve according to claim 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 applies force to the valve body along the axial direction of the valve body,
In the passage in the valve body, an opening area of the downstream end is smaller than an inner diameter area of the biasing body. The damping force control valve according to claim 1 or 2,
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 large-diameter portion toward the second working fluid chamber. It is larger than the diameter of the part. A damping force control valve according to claim 3,
The large diameter portion has a step where the diameter of the passage changes. The damping force control valve according to claim 3 or 4,
The large diameter portion has a tapered shape in which the diameter of the passage increases as it approaches the downstream end. A damping force control valve according to any one of claims 3 to 5,
When the valve body is viewed in the axial direction, 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 body. A damping force control valve according to any one of claims 1 to 6,
There is substantially only fluid in the passage of the valve body. A damping force control valve according to any one of claims 1 to 7,
The direction of the flow in which the working fluid in the first working fluid chamber is discharged out of the first working fluid chamber through the port is along the axial direction of the valve body. A shock absorber,
The shock absorber includes 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 out of the first working fluid chamber through the port in the damping force control valve.

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