JP2013170602A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact shock absorber capable of ensuring a wide range of a controllable flow range, while ensuring superior traveling performance even when the energization becomes impossible.SOLUTION: A damping force control valve arranged in a bypass comprises a valve element 20 which is reciprocated straight by a solenoid, a first hydraulic fluid chamber 30, a second hydraulic fluid chamber 40 in which an end on the opposite side to an end face of the valve element 20 is exposed, an urging body for applying the force to the valve element along the axial direction of the valve element 20, and a passage for bringing the first hydraulic fluid chamber 30 in communication with the second hydraulic fluid chamber 40. The degree of opening of the flow path formed of the gap between the end face of the valve element 20 and the port is changed according to the position of the end face of the valve element 20. The damping force is controlled thereby. When the degree of opening of the flow path is maximum, the valve element 20 is separated from the port. When the solenoid 23 is not energized, the force toward the port 30a along the axial direction of the valve element is applied to the valve element 20 by the urging body. Thus, the valve element 20 is moved to the closing position.

Description

  The present invention relates to 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 an orifice, valve, etc. with a relatively small channel area as a damping force generator, and the damping force is generated by the fluid resistance when passing through these narrow channels. To attenuate the vibration generated in the vehicle.

  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 inside a cylinder and a shock absorber in which a valve is installed outside the cylinder. In either case, the main damping force generating part A damping force control valve is installed during bypass, and the damping force can be controlled by adjusting the opening degree of the damping force control valve in accordance with the traveling conditions.

  As a conventional damping force control valve, there is a valve that attempts to ensure good running performance when the flow control valve uses a solenoid and the valve closes and becomes hard when energization is impossible due to disconnection or the like. (For example, refer to Patent Document 1).

  7 is a longitudinal sectional view schematically showing the shock absorber 401 shown in Patent Document 1. FIG. 7 (a) shows the shock absorber 401 at the time of hardware characteristics (when fully closed), and FIG. 7 (b). Shows a shock absorber 401 at the time of soft characteristics (see FIG. 1 of Patent Document 1).

  The shock absorber 401 includes a cylinder 402 having a piston 403. A space in the cylinder 402 is divided by a piston 403 into a cylinder upper chamber 402a and a cylinder lower chamber 402b. Main oil liquid passages 407 and 408 are provided in the piston 403. Damping force generators 409 and 410 are provided in the main oil liquid passages 407 and 408. On the other hand, the bypass 412 is provided with a damping force generator 413 and a check valve 414. The flow resistance of the damping force generation unit 413 is smaller than the damping force generation units 409 and 410 of the main oil liquid passages 407 and 408.

  A cylindrical guide member 415 having an opening 416 is installed in the bypass 412. A shutter-shaped valve element 417 is provided inside the guide member 415. The valve body 417 is provided with passages 419 and 420. The valve body 417 is installed on the rod 423. The rod 423 is supported by the support member 421 and linearly reciprocates by the solenoid actuator 424. Thereby, the opening degree of the flow path between the opening 416 and the passage 419 is adjusted. That is, the damping force control in the bypass 412 is performed by adjusting the flow path area of the bypass 412.

  In FIG. 7A, since the bypass 412 is fully closed by the valve body 417, the damping force characteristic is a hard characteristic. On the other hand, in FIG. 7B, since the bypass 412 is opened by the valve body 417, the damping force characteristic is a soft characteristic. When not energized, the bypass 412 is fully closed.

Japanese Patent No. 3060078

  In the shock absorber 401 shown in FIG. 7, since the valve body 417 has a shutter shape, the range of the flow rate that can be controlled in the bypass 412 (the minimum value and the maximum value of the area of the communication portion between the opening 416 and the passage 419). In order to increase the difference), it is necessary to secure a large area where the valve body 417 and the guide member 415 are opposed to each other in the radial direction. Therefore, the radial dimension of the valve body 417 must be increased.

  If it does so, the area of the sliding part F of the guide member 415 and the valve body 417 will become large, and friction will become large. Moreover, since the widened sliding portion F is located in the oil flow, minute foreign matter enters the sliding portion, and the friction further increases. In order to cope with the increase in friction, it is necessary to strengthen the spring 422 for biasing the valve body 417 in the closing direction. When the spring 422 becomes stronger, the solenoid actuator 424 for driving the valve body 417 also becomes larger.

  Further, the rod 423 that connects the solenoid actuator 424 and the valve body 417 protrudes from the support member 421 so that the valve body 417 blocks the oil passage (bypass 412) when the energization is disabled. At this time, if the oil pressure around the valve body 417 is high, the protruding movement of the rod 423 is hindered. Therefore, in order for the projecting movement of the rod 423 to overcome this hydraulic pressure, it is necessary to further strengthen the spring 422, and further increase the size of the solenoid actuator 424. In the field of vehicles such as motorcycles and automobiles, the installation space for equipment is limited, so there is a strong demand for making the installation space for valves as small as possible. In addition, from the viewpoint of improving running performance, there is a strong demand for lighter valves. Therefore, enlargement of the valve must be avoided as much as possible.

  The present invention has been made in view of the above-mentioned problems, and is small in size and can secure a wide range of controllable flow rate while ensuring good running performance even when energization is disabled. It is to provide a shock absorber.

The present invention employs the following configuration in order to solve the above-described problems.
(1) A shock absorber,
The shock absorber is
A damping force generator that generates a damping force by the fluid resistance of the working fluid;
A damping force control valve disposed in the bypass with respect to the damping force generation unit,
The damping force control valve is
A 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 in which an end opposite to the end face of the valve body is exposed;
An urging body that applies force to the valve body along an axial direction of the valve body;
A passage communicating the first working fluid chamber and the second working fluid chamber;
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 maximized, the valve body is separated from the port, while when the solenoid is not energized, the biasing body causes a force toward the port along the axial direction of the valve body. The valve body is moved to the closed position.

  According to the configuration of (1), the end face of the valve body and the port face each other, and the gap between the end face of the valve body and the port is a flow path through which the working fluid passes. The opening degree of the flow path is changed depending on the position of the end face of the valve body that linearly reciprocates in the axial direction, and thereby the damping force is controlled. Unlike the shock absorber shown in FIG. 7, the amount of change in the flow path area with respect to the stroke of the valve element (axial displacement) is large. Therefore, it is possible to ensure a wide range of flow rate that can be controlled in the bypass without increasing the diameter of the valve body.

  In the first working fluid chamber, the distance between the end face of the opposing valve body and the port is a flow path through which the working fluid passes. Therefore, when adjusting the position of the end face of the valve body, The wall does not slide. Therefore, an increase in friction due to sliding can be avoided. In addition, since there is no sliding portion around the flow path through which the working fluid passes, there is no increase in friction due to the biting of minute foreign matter.

  Since the first working fluid chamber and the second working fluid chamber communicate with each other through the valve body passage, the working fluid in the first working fluid chamber is discharged out of the first working fluid chamber through the port. The pressure difference between the downstream end of the valve element and the end opposite to the downstream end is small with respect to the direction. Therefore, the generation of a pressure difference between the first working fluid chamber and the second working fluid chamber can be suppressed. Therefore, there is no need to strengthen the urging body unlike the shock absorber shown in FIG. An increase in the size of the solenoid can be avoided.

  When the solenoid is not energized, the urging body applies a force toward the port along the axial direction of the valve body. At this time, the valve body pushes away the working fluid in the first working fluid chamber and moves toward the port, but the pressure at that time propagates to the second working fluid chamber 40 through the passage, so that the first working fluid Increase in indoor pressure is suppressed. Further, as described above, an increase in friction during movement of the valve body is prevented. Therefore, the interval between the end face of the valve body and the port can be quickly closed only by the urging force of the urging body. As described above, since the generation of resistance (friction and pressure rise) to the valve body when the valve body moves toward the port is suppressed as much as possible, it has excellent responsiveness when the solenoid is not energized, and quickly Hard characteristics can be obtained.

  Therefore, the shock absorber (1) is small and can secure a wide range of controllable flow rates while ensuring good running performance even when power is not available.

(2) The shock absorber according to (1),
The passage is provided along the axial direction of the valve body, and when the solenoid cannot be energized and the interval between the valve body and the port is narrowed, the first working fluid chamber and the second operation fluid are provided. Of the fluid chambers, it is preferable to reduce the pressure difference between the two working fluid chambers by flowing the working fluid from the high pressure side working fluid chamber to the low pressure side working fluid chamber.

  According to the structure of (2), the channel | path which connects a 1st working fluid chamber and a 2nd working fluid chamber is comparatively short. Therefore, pressure transmission between the first working fluid chamber and the second working fluid chamber occurs promptly when the interval between the end face of the valve element and the port (flow path for the working fluid) is closed. Thereby, generation | occurrence | production of the pressure difference of a 1st working fluid chamber and a 2nd working fluid chamber can be suppressed more effectively. Therefore, the responsiveness can be further improved.

(3) The shock absorber according to (2),
The passage passes through the valve body along the axial direction of the valve body, and when the solenoid cannot be energized and the distance between the valve body and the port becomes narrow, the first working fluid chamber and While the pressure difference with the second working fluid chamber is reduced, the passage approaches the port. .

  According to the configuration of (3), the passage communicating the first working fluid chamber and the second working fluid chamber is further shortened, and the passage approaches the port when the distance between the valve body and the port is narrowed. Responsiveness can be improved. Further, since the passage is provided in the valve body, it is not necessary to secure a space for forming the passage outside the valve body. Therefore, an increase in the size of the valve can be avoided.

(4) The shock absorber according to any one of (1) to (3),
The urging body is preferably installed in the first working fluid chamber and applies a force toward the port along the axial direction of the valve body to the valve body.

  According to the configuration of (4), since the valve body can be smoothly moved by pulling the valve body to the first working fluid chamber side by the biasing body, the position stability of the valve body and Responsiveness is further improved.

(5) The shock absorber according to any one of (1) to (4),
The biasing body is installed at a position where a part of the biasing body overlaps the passage in the axial direction of the valve body, and is directed to the port along the axial direction of the valve body with respect to the valve body. It is preferable to apply force.

  According to the structure of (5), since an urging body and a valve body can be arrange | positioned compactly, a damping force control valve can be reduced in size.

(6) The shock absorber according to any one of (1) to (4),
The biasing body is installed at a position where the entire biasing body overlaps with the passage in the axial direction of the valve body, and the force toward the port along the axial direction of the valve body is applied to the valve body. Add

  According to the configuration of (6), since the urging body and the valve body can be arranged more compactly, the damping force control valve can be further reduced in size.

  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 secure a wide range of flow rates that are small and controllable while ensuring a good running performance even when energization is disabled.

It is a longitudinal cross-sectional view which shows typically an example of the damping force control valve with which the shock absorber of this invention is provided. It is a longitudinal cross-sectional view which shows typically the open state (a) of a damping force control valve shown in FIG. 1, a micro opening degree state (b), and a closed state (c). It is a longitudinal cross-sectional view which shows typically the open state (a) of the other damping force control valve which concerns on this invention, a micro opening degree state (b), and a closed state (c). It is a longitudinal cross-sectional view which shows typically the open state (a) of the other damping force control valve which concerns on this invention, a micro opening degree state (b), and a closed state (c). 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 longitudinal cross-sectional view which shows the conventional shock absorber typically.

Embodiments of the present invention will be described below with reference to the drawings.
First, the damping force control valve 10 provided in the shock absorber 100 according to the present invention will be described.
FIG. 1 is a longitudinal sectional view schematically showing a damping force control valve 10 provided in the shock absorber 100 of the present invention.
FIG. 1 shows a closed state when the damping force control valve 10 is not energized.
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 shock absorber 100, the guide hole 13 b and the first port 30 a are formed at positions facing each other across the space in the first working fluid chamber 30. The distance between the guide hole 13b and the first port 30a is longer than the distance between the first port 30a and the second port 30b. The distance between the guide hole 13b and the second port 30b is longer than the distance between the first port 30a and the second port 30b. In the axial direction S, the second port 30b is closer to the first port 30a than the guide hole 13b. In the axial direction S, the second port 30b is provided between the guide hole 13b and the first port 30a. A member that slides with the valve body 20 is not provided in the first working fluid chamber 30.
In the shock absorber 100, the guide hole 13b and the valve body 20 slide, but a portion where the guide hole 13b and the valve body 20 slide is provided at a position away from the first port 30a and the second port 30b. Therefore, an increase in friction due to minute foreign matter can be suppressed.

  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 10 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 in an open state (a), a minute opening state (b), and a closed state (c).

  In the damping force control valve 10, slant processing is applied to a part (substantially half) of the end surface 20 a (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. When the solenoid coil 23 is energized and the damping force control valve 10 is in the open state, the valve body 20 is separated from the first port 30a as shown in FIG. When the valve body 20 and the first port 30a are separated, the interval between the entire outer peripheral edge of the valve body 20 and the entire outer peripheral edge of the first port 30a is the working fluid flow path T.

  In the state shown in FIG. 2A, when the energization to the solenoid coil 23 is interrupted, the valve body 20 is moved to the downstream direction D side by the coil springs 18, 34, and 35. At this time, the passage 21 also moves in the downstream direction D.

  FIG. 2B shows a state when the valve body 20 is moving toward the downstream direction D side. In FIG. 2B, the flat portion 20d of the end surface 20a of the valve body 20 is the axis line. In the direction S, it exists at the same position as the first port 30a. There is a gap between the inclined portion 20e and the first port 30a. This interval is the working fluid flow path T. Since the large-diameter portion 21a is formed in the valve body 20, when a part of the working fluid that has passed through the working fluid flow path T flows in the opposite direction U, a vortex is formed in the large-diameter portion 21a and diffused. As a result, it becomes easier to head in the downstream direction D. Therefore, the generation of a pressure difference between the first working fluid chamber 30 and the second working fluid chamber 40 can be suppressed more efficiently.

  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.

  The valve body 20 is further moved in the downstream direction D from the state shown in FIG. 2 (b) by the coil springs 18, 34, and 35, and stops at the position shown in FIG. 2 (c). This position is the closed position of the valve body 20. The closed position is a position on the most downstream direction D side where the valve element 20 is moved by the coil springs 18, 34, 35 when the solenoid coil 23 is not energized. When the valve body 20 is in the closed position, the first port 30a is preferably closed by the valve body 20. In other words, it is preferable that the first port 30a is substantially fully closed by the valve body 20 when the valve body 20 is in the closed position. The substantially fully closed state here means that a slight amount of opening is allowed depending on the use state or the like. The first port 30 a may be completely closed by the valve body 20. In the shock absorber 100, when the valve body 20 is located at the closed position, the downstream end D side of the passage 21 enters the first port 30a, and the passage 21 communicates with the working fluid chamber 31.

  Since the valve body 20 is formed with a passage 21 that allows the first working fluid chamber 30 and the second working fluid chamber 40 to communicate with each other, a damping force is provided as shown in FIGS. When the control valve 10 shifts from the open state to the closed state, the pressure of the working fluid in the first working fluid chamber 30 is transmitted to the second working fluid chamber 40, and thus the first working fluid chamber 30 and the second working fluid chamber 40. Can be suppressed from occurring. Accordingly, the valve body 20 can be quickly moved to the closed position by the coil springs 18, 34, 35 when the solenoid is not energized.

Next, another embodiment of the damping force control valve will be described.
FIG. 3 is a longitudinal sectional view schematically showing an open state (a), a minute opening state (b), and a closed state (c) of a damping force control valve according to another embodiment of the present invention. 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 components as those in FIG. 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 in a non-energized state in the state shown in FIG. 3A, the valve body 20 moves in the downstream direction D. Thereby, the damping force control valve 10 becomes a minute opening degree. At this time, as shown in FIG.3 (b), the flow path T is the space | interval of all the outer periphery of the valve body 20, and the fully open periphery of the 1st port 30a. Thereafter, the valve body 20 further moves in the downstream direction D. As shown in FIG. 3C, the end surface 20a ′ of the valve body 20 and the first port 30a are located at the same position in the axial direction S, The first port 30 a is closed by the end face 20 a ′ of the body 20. At this time, the end surface 20a ′ of the valve body 20 is located at the closed position.

Next, another embodiment of the present invention will be described.
FIG. 4 is a longitudinal sectional view schematically showing an open state (a), a minute opening state (b), and a closed state (c) of a damping force control valve according to another embodiment of the present invention. 4 is the same as FIG. 2 except for the shape of the downstream end D side of the valve body 20. In FIG. 4, the same components as those in FIG. The description will be omitted or simplified.

  In the damping force control valve 10 shown in FIG. 4, the valve body 20 includes a passage 21 that penetrates the valve body 20 in the axial direction S, but the large-diameter portion 21 a is not formed. The valve body 20 includes an annular end surface 20a ″. When the solenoid coil 23 is in a non-energized state in the state shown in FIG. 4A, the valve body 20 moves in the downstream direction D. Thereby, the damping force control valve 10 becomes a minute opening degree. At this time, as shown in FIG. 4B, the flow path T is the distance between the entire outer peripheral edge of the valve body 20 and the fully open peripheral edge of the first port 30a. Thereafter, the valve body 20 further moves in the downstream direction D, and as shown in FIG. 4C, the end surface 20a ″ of the valve body 20 and the first port 30a exist at the same position in the axial direction S, The first port 30 a is closed by the end surface 20 a ′ of the valve body 20. At this time, the end surface 20a ′ of the valve body 20 is located at the closed position.

  Also in the damping force control valve 10 shown in FIGS. 3 and 4, the passage 21 can suppress the occurrence of a pressure difference between the first working fluid chamber 30 and the second working fluid chamber 40. It can be quickly moved to the closed position.

Next, a shock absorber 100 according to an embodiment of the present invention will be described.
5 and 6 are hydraulic circuit diagrams showing a shock absorber 100 including 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 serving as a damping force generation unit includes damping valves 148 and 150 having 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, the damping valve 116b having a plurality of shims, and the 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. 2A, 2B, 3A, 3B, and 4A, 4B, the damping force control valve 10 supplies the working fluid to the working fluid path. It is possible to flow in the direction from 32 to the working fluid path 31 via the first working fluid chamber 30. The damping force control valve 10 can also flow 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.5 and FIG.6.

  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. 6, 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 shock absorber 100, the end surface 20a of the valve body 20 and the first port 30a face each other, and the gap between the entire outer peripheral edge of the end surface 20a of the valve body 20 and the entire outer peripheral edge of the first port 30a is large. The flow path T of the working fluid. The opening degree of the flow path T is changed depending on the position of the end face 20a of the valve body 20, and thereby the damping force is controlled. Since the change amount of the flow path area with respect to the stroke of the valve body 20 is large, it is possible to ensure a wide range of flow rate that can be controlled in the bypass with respect to the damping valve 116b as the damping force generation unit without increasing the diameter of the valve body 20.

  Further, in the first working fluid chamber 30, the interval between the end surface 20 a of the valve body 20 and the first port 30 a is the flow path T of the working fluid. Therefore, when adjusting the position of the end surface 20 a of the valve body 20, The inner wall surface of one working fluid chamber 30 does not slide. Therefore, an increase in friction due to sliding can be avoided. In addition, since there is no sliding portion around the working fluid flow path T, there is no increase in friction due to the biting of minute foreign matter.

  Further, since 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, the end face 20 a on the downstream direction D side of the valve body 20 and the opposite direction U side. The pressure difference with the end face 20b is small. Therefore, the generation of a pressure difference between the first working fluid chamber 30 and the second working fluid chamber 40 can be suppressed. As a result, enlargement of the solenoid can be avoided.

  When the solenoid is not energized, the coil springs 18, 34, and 35 apply a force toward the first port 30 a along the axial direction of the valve body 20 to the valve body 20. At this time, the valve body 20 pushes away the working fluid in the first working fluid chamber 30 and moves toward the first port 30 a, and the pressure at that time propagates to the second working fluid chamber 40 through the passage 21. Therefore, an increase in the pressure of the first working fluid chamber 30 is suppressed. Further, since sliding between the valve body 20 and other members does not occur in the first working fluid chamber 30, an increase in friction during movement of the valve body 20 is prevented. Therefore, the interval between the end surface 20a of the valve body 20 and the first port 30a can be quickly closed only by the urging force of the coil springs 18, 34, and 35. Thus, since the generation of resistance (friction and pressure rise) to the valve body 20 when the valve body 20 moves toward the first port 30a is suppressed as much as possible, the responsiveness when the solenoid is not energized is excellent. The hardware characteristics can be obtained quickly. Therefore, the shock absorber 100 is small in size and can secure a wide controllable flow rate range while ensuring good running performance even when energization is disabled.

  Moreover, since the passage 21 penetrates the valve body 20 along the axial direction of the valve body 20, the passage 21 is short. Accordingly, when the solenoid coil 23 cannot be energized and the distance between the valve body 20 and the first port 30a becomes narrow, the pressure difference between the high pressure side first working fluid chamber 30 and the low pressure side second working fluid chamber 40 is reduced. It can be quickly reduced and has excellent responsiveness. Further, since the passage 21 is provided in the valve body 20, the space for forming the passage 21 may not be secured outside the valve body 20. Therefore, an increase in the size of the valve can be avoided.

  In addition, coil springs 34 and 35 are installed in the first working fluid chamber 30 and apply a force toward the first port 30 a along the axial direction of the valve body 20 to the valve body 20. It can be pulled out smoothly to the one working fluid chamber 30 side.

  Further, the coils 34 and 35 are installed at positions where the coils 34 and 35 overlap with the passage 21 in the axial direction S of the valve body 20, and the first port along the axial direction S of the valve body 20 with respect to the valve body 20. Apply force toward 30a. Therefore, since the coil springs 34 and 35 and the valve body 20 can be arranged more compactly, the damping force control valve 10 can be further downsized.

  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. Although the shock absorber 100 shown in FIGS. 5 and 6 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, it is preferable that the working fluid can be flowed in a direction in which the working fluid is discharged from at least the first working fluid chamber 30 via 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 shock absorber 100, a damping force adjusting device 116 is installed between the hydraulic cylinder 112 and the reservoir tank 114, and a check valve 116c as a damping force generating unit that generates a contracting damping force is provided in the damping force adjusting device 116. The damping force control valve 10 is installed in a bypass with respect to the damping valve 116b. At the time of retraction, in the damping force adjusting device 116, the working fluid corresponding to the volume of the piston rod 162 entering the hydraulic cylinder 112 flows. A part of the working fluid flows through the damping valve 116 b and the remaining part of the working fluid flows through the damping force control valve 10. At this time, the damping valve 116b and the damping force control valve 10 are in a bypass relationship with each other. Note that the present invention is not limited to this example. For example, in the shock absorber 100, a damping valve as a damping force generation unit may be installed instead of the check valve 116c. In this case, the damping force control valve 10 is installed in a bypass with respect to the check valve 116c that generates an elongation damping force. At the time of extension, in the damping force adjusting device 116, the working fluid corresponding to the volume of the piston rod 162 that retreats from the hydraulic cylinder 112 flows. A part of the working fluid flows through the damping valve, and the rest of the working fluid flows through the damping force control valve 10. At this time, the damping valve and the damping force control valve 10 are in a bypass relationship with each other.

  As described above, in the present invention, the damping force control valve 10 may be installed outside the hydraulic cylinder 112 in a bypass with respect to the damping force generation unit (attenuation valve 116b) that generates a contraction damping force. You may install in the bypass with respect to the damping force generation | occurrence | production part to generate | occur | produce, and may be installed in both bypasses.

  Further, the damping force control valve 10 may be installed in a bypass for the damping valve 150 in the hydraulic cylinder 112. At the time of degeneration, working fluid corresponding to the volume reduction of the working fluid chamber 158 flows through the damping valve 150. A part of the working fluid flows through the damping valve 150, and the rest of the working fluid flows through the damping force control valve 10. At this time, the damping valve 150 and the damping force control valve 10 are in a bypass relationship with each other. Further, the damping force control valve 10 may be installed in a bypass for the damping valve 150 in the hydraulic cylinder 112. At the time of extension, the working fluid corresponding to the volume decrease of the working fluid chamber 160 flows through the damping valve 148. A part of the working fluid flows through the damping valve 148, and the rest of the working fluid flows through the damping force control valve 10. At this time, the damping valve 148 and the damping force control valve 10 are in a bypass relationship with each other.

  As described above, in the present invention, the damping force control valve 10 may be installed in the hydraulic cylinder 112 in a bypass with respect to the damping force generation unit (damping valve 150) that generates the contraction damping force. It may be installed in the bypass for the damping force generation unit (attenuation valve 148) to be generated, or may be installed in both bypasses. In this invention, the damping force control valve 10 should just be installed in the bypass with respect to a damping force generation | occurrence | production part, and the installation position and installation aspect of the damping force control valve 10 are not specifically limited.

  In the shock absorber 100, the passage 21 passes through the valve body 20 in the axial direction S. However, in the present invention, the formation position of the passage 21 is not limited to this example. For example, the passage may be formed on the outer peripheral side surface of the valve body 20 along the axial direction S. Further, the passage may not be formed in the valve body 20. For example, the passage may be formed in a member that faces the outer peripheral side surface of the valve body 20 along the axial direction S.

  In the shock absorber 100, coil springs 34 and 35 as urging bodies are installed in the first working fluid chamber 30. The coil spring 35 is an urging body that applies a force toward the first port 30a to the valve body 20 when extended. The coil spring 34 is a biasing body that applies a force toward the first port 30a to the valve body 20 when retracted. In the present invention, either one of these two urging bodies may be provided.

  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 oil passage is not limited to the above example, and the cross section of the oil passage 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 100 shock absorber

Claims (6)

A shock absorber,
The shock absorber is
A damping force generator that generates a damping force by the fluid resistance of the working fluid;
A damping force control valve disposed in the bypass with respect to the damping force generation unit,
The damping force control valve is
A 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 in which an end opposite to the end face of the valve body is exposed, and an urging body that applies force to the valve body along the axial direction of the valve body,
A passage communicating the first working fluid chamber and the second working fluid chamber;
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 maximized, the valve body is separated from the port, while when the solenoid is not energized, the biasing body causes a force toward the port along the axial direction of the valve body. The valve body is moved to the closed position. The shock absorber according to claim 1,
The passage is provided along the axial direction of the valve body, and when the solenoid cannot be energized and the interval between the valve body and the port is narrowed, the first working fluid chamber and the second operation fluid are provided. By flowing the working fluid from the working fluid chamber on the high pressure side to the working fluid chamber on the low pressure side of the fluid chamber, the pressure difference between the two working fluid chambers is reduced. The shock absorber according to claim 2,
The passage passes through the valve body along the axial direction of the valve body, and when the solenoid cannot be energized and the distance between the valve body and the port becomes narrow, the first working fluid chamber and While the pressure difference with the second working fluid chamber is reduced, the passage approaches the port. The shock absorber according to any one of claims 1 to 3,
The urging body is installed in the first working fluid chamber, and applies a force toward the port along the axial direction of the valve body to the valve body. The shock absorber according to any one of claims 1 to 4,
The biasing body is installed at a position where a part of the biasing body overlaps the passage in the axial direction of the valve body, and is directed to the port along the axial direction of the valve body with respect to the valve body. Apply power. The shock absorber according to any one of claims 1 to 4,
The biasing body is installed at a position where the entire biasing body overlaps with the passage in the axial direction of the valve body, and the force toward the port along the axial direction of the valve body is applied to the valve body. Add

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