Pilot-type selector valve and shock absorber

Abstract

This pilot-type selector valve (20) has: a drive unit (30) that operates by being energized; a first valve body (53) that is a valve body that opens a flow path (R) by the operation of the drive unit (30); and a second valve body (61) that is a valve body that can open and close the flow path (R) together with the first valve body (53) and that further opens the flow path (R) by means of a pressure difference between the upstream side and the downstream side of the first valve body (53) when the first valve body (53) opens the flow path (R). The drive unit (30) can contact a second valve body (61) in a state in which the flow path (R) is open.

Description

Pilot-operated switching valve and shock absorber

[0001] The present invention relates to a pilot-operated switching valve and a shock absorber.

[0002] For example, it is known that a pilot-operated switching valve is provided inside a shock absorber of a saddle-ride type vehicle to open and close a flow path through which oil flows. Patent Document 1 discloses a conventional technique in which a pilot-operated switching valve is provided.

[0003] The shock absorber shown in Patent Document 1 has a drive unit that is activated when electricity is applied, a first valve body that opens the flow path when the drive unit is activated, and a second valve body that further opens the flow path due to a pressure difference when the first valve body opens the flow path.

[0004] By opening the first valve body, which is smaller than the second valve body, first, the second valve body is opened using the pressure difference. Since only a small force is required to open the small first valve body, only a small force is required to open the flow path.

[0005] Japanese Patent Application Laid-Open No. 2016-176552

[0006] The inventors of the present invention have studied the pilot-operated switching valve disclosed in Patent Document 1 and found that there is a risk of the second valve element vibrating when the flow path is open. This is thought to be because the opening amount of the second valve element depends on the flow rates through the first and second valve elements, which in turn depend on the opening amount of the second valve element, resulting in non-convergent oscillatory motion. It has also been found that the use of such a pilot-operated switching valve in a shock absorber may also affect the damping force generated by the shock absorber.

[0007] An object of the present invention is to provide a pilot-operated switching valve that can suppress vibration of the second valve body.

[0008] As a result of extensive research, the inventors have discovered that vibration of the second valve body can be suppressed by bringing a drive unit for pushing the first valve body into contact with the second valve body in a state in which the flow path is open. The present invention was completed based on this discovery.

[0009] The present disclosure will be described below.

[0010] According to the present disclosure, there is provided a pilot-operated switching valve having a drive unit that is activated when current is applied, a first valve body that is a valve body that opens a flow path when the drive unit is activated, and a second valve body that is capable of opening and closing the flow path together with the first valve body, and that is a valve body that, when the first valve body opens the flow path, further opens the flow path due to a pressure difference between the upstream and downstream sides of the first valve body, wherein the drive unit is capable of maintaining the second valve body in an open state even when it is in a state where the flow path is open.

[0011] According to the present invention, it is possible to provide a pilot-operated switching valve capable of suppressing vibration of the second valve body.

[0012] FIG. 1 is a front view of a shock absorber equipped with a pilot-operated switching valve according to an embodiment. FIG. 2 is an enlarged view of part 2 of FIG. 1. FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2. FIG. 4A is a front view of the second pressing part, and FIG. 4B is a side view of the second pressing part. FIG. 5A is a diagram illustrating the pilot-operated switching valve before the drive part is activated, FIG. 5B is a diagram illustrating the operation of the pilot-operated switching valve when the drive part is pressing the first valve body, and FIG. 5C is an enlarged view of part 5C of FIG. 5B. FIG. 6A is a diagram illustrating the operation when the second valve body is pressed down, and FIG. 6B is an enlarged view of part 6B of FIG. 6A. FIG. 6B is a diagram illustrating the relationship between time and the position of the second valve body.

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. The embodiments shown in the accompanying drawings are merely examples of the present invention, and the present invention is not limited to these embodiments.

[0014] <Example> Refer to Figure 1. Figure 1 shows a telescopic shock absorber 10 that constitutes a main part of a front fork. The front fork is provided at the front of a saddle-ride type vehicle such as a motorcycle, and suppresses the transmission of vibrations received from the road surface to the vehicle body.

[0015] The shock absorber 10 is used by spanning from the vicinity of the head pipe to the front wheel of a motorcycle. When a motorcycle is traveling, vibrations are input from the front wheel due to the influence of unevenness in the road surface, etc. At this time, the shock absorber 10 compresses and expands, generating a damping force.

[0016] The shock absorber 10 mainly comprises a cylindrical outer tube 11 that extends downward from the motorcycle's head pipe toward the front wheel, a cylindrical inner tube 12 that extends upward from the front wheel toward the head pipe with its tip inserted inside the outer tube 11, and a coil spring (not shown) that biases the outer tube 11 and inner tube 12 in directions separating them from each other. The space enclosed by the outer tube 11 and inner tube 12 is filled with oil as a working fluid.

[0017] The shock absorber 10 has an outer tube lid portion 16 that closes the upper end (terminal end) of the outer tube 11 and an axle holder 17 that closes the lower end (terminal end) of the inner tube 12.

[0018] A pressure accumulator 18 into which excess oil can flow from the inner tube 12 is provided at a location adjacent to the lower part of the inner tube 12. A pilot-operated switching valve 20 that opens and closes an oil flow path R from the inner tube 12 to the pressure accumulator 18 is provided between the inner tube 12 and the pressure accumulator 18. The flow path R is a portion that connects the inside of the pilot-operated switching valve 20, the inside of the inner tube 12, and the pressure accumulator 18.

[0019] The pressure accumulator may be a bladder or a free piston. Furthermore, any pressure accumulator other than a bladder or a free piston may be used as long as it can store excess oil in the inner tube. The pressure accumulator may be provided on the axis of the inner tube.

[0020] Please refer to Figures 2 and 3. Figures 2 and 3 show the main part of the pilot-operated switching valve 20. The case 21 is shown schematically to facilitate understanding of the invention.

[0021] The pilot-operated switching valve 20 has a substantially cylindrical case 21 with a bottom, a drive unit 30 that operates when electricity is applied, a partition member 23 that is provided adjacent to the tip of the drive unit 30 and that partitions a flow path R within the case 21, a first valve 50 that is a valve that opens the flow path R when the drive unit 30 is activated, a second valve 60 that is a valve that further opens the flow path R due to a pressure difference when the first valve 50 opens the flow path R, a valve storage member 26 that stores the first valve 50 and the second valve 60, and a valve guide member 27 that is a cylindrical member stored in the valve storage member 26 and guides the second valve 60.

[0022] The case 21 has, for example, a cylindrical inner periphery with a bottom, and includes a first flow passage hole 21a that is opened to allow oil to flow in from the inner tube 12 (see FIG. 1 ), and a second flow passage hole 21b that is opened to allow oil to pass through that flows to the pressure accumulator 18 (see FIG. 1 ).

[0023] The drive unit 30 has a cylindrical drive unit main body 31 whose tip is fastened to the case 21, a rod 32 that is movable back and forth along the axis CL of the drive unit main body 31, a coil 33 that is wound around the outer periphery of the rod 32 and can be electrified, a plunger 40 that is mounted at the tip of the rod 32 and can move back and forth along the axis CL together with the rod 32, a retraction stopper 35 that is fixed to the inner surface of the drive unit main body 31 and determines the retraction limit of the plunger 40, and a plunger guide portion 36 that is fixed to the inner surface of the drive unit main body 31 and guides the plunger 40.

[0024] The tip of the drive unit body 31 abuts against a stepped portion formed inside the case 21. This positions the entire drive unit 30.

[0025] A spring (not shown) applies a biasing force to the rod 32 in the backward direction.

[0026] A battery (not shown) is connected to the coil 33, allowing it to be energized. The control unit switches on and off the energization of the coil 33. Various sensors are connected to the control unit, and the control unit switches on and off the energization of the coil 33 based on electrical signals from these sensors.

[0027] The plunger 40 has a first pressing portion 41 that abuts against the tip of the rod 32 and is approximately T-shaped, a leaf spring 42 through which the first pressing portion 41 passes and abuts against a flange-shaped portion of the first pressing portion 41, and a second pressing portion 43 into which the tip of the first pressing portion 41 is inserted and abuts against the leaf spring 42.

[0028] The first pressing portion 41 has a rod abutting portion 41a against which the rod 32 abuts, and a first pressing portion main body 41b extending from the center of the rod abutting portion 41a along the axis CL.

[0029] The leaf spring 42 is formed by a ring-shaped portion having a plurality of wing-shaped springs extending from the ring portion toward the center.

[0030] 2, 4A, and 4B, the second pressing portion 43 includes a bottomed, cylindrical leaf spring abutment portion 43a that sandwiches the leaf spring 42 together with the retraction stopper 35, a cylindrical connecting portion 43b that extends from the center of the leaf spring abutment portion 43a along the axis CL and into which the first pressing portion body 41b is press-fitted, a second shaft portion 43c that is a shaft-like portion that extends from the tip of the connecting portion 43b along the axis CL and is capable of abutting against the second valve 60, and a first shaft portion 43d that extends from the tip of the second shaft portion 43c along the axis CL and is capable of abutting against the first valve 50.

[0031] The second shaft portion 43c has a non-circular cross section. Specifically, the second shaft portion 43c is formed in a plate shape with a thickness that gradually decreases from the cylindrical connecting portion 43b toward the first shaft portion 43d. Furthermore, the plate-shaped second shaft portion 43c has a shoulder portion 61c (inclined surface) in the width direction that tapers toward the first shaft portion 43d and can abut against the periphery of the second valve hole 61a of the second valve body 61. This configuration allows oil to pass through the second valve hole 61a when the shoulder portion 61c abuts against the periphery of the second valve hole 61a of the second valve body 61. The tip of the shoulder portion 61c is formed as a tapered surface that tapers toward the first shaft portion 43d. This shoulder portion 61c is not limited to an inclined surface, and may be stepped.

[0032] 2 , the plunger guide portion 36 has a tapered guide portion tapered surface portion 36a that is part of the outer peripheral surface and is inclined with respect to the axis CL. The guide portion tapered surface portion 36a is spaced apart from the partition member 23. This allows oil to pass between the guide portion tapered surface portion 36a and the partition member 23.

[0033] A partition member hole 23a through which oil can pass is formed around the axis CL in the partition member 23. The partition member hole 23a constitutes a part of the flow path R, and is opened and closed by the first valve 50 and the second valve 60.

[0034] The first valve 50 includes a biasing member 51 composed of a compression coil spring and having one end abutting against the valve storage member 26, a receiving member 52 that receives the other end of the biasing member 51, a first valve body 53 that is fixed to the receiving member 52 and can open and close a portion of the flow path R, and a first valve seat portion 54 that is formed in the second valve 60 and against which the first valve body 53 abuts when it is in a state where the flow path R is closed.

[0035] The second valve 60 has a second valve body 61 having a cylindrical shape with a bottom, and a second valve seat portion 62 formed in the partition member 23 and against which the second valve body 61 abuts when the flow path R is closed.

[0036] The biasing member 51 biases the second valve body 61 in the closing direction via the first valve body 53, and also constitutes a part of the second valve 60. In other words, it can be said that the second valve 60 also includes the biasing member 51.

[0037] The receiving member 52 is displaceable in the axial direction along the inner circumferential surface of the second valve body 61. In other words, the movement direction of the first valve body 53 is guided by the inner circumferential surface of the second valve body 61 via the receiving member 52. A receiving member oil hole 52a is formed between the receiving member 52 and the inner circumferential surface of the second valve body 61 to allow oil to pass through.

[0038] The tip of the receiving member 52 is formed to have a smaller outer diameter than the other portions, and a predetermined space is formed between the tip and the second valve body 61.

[0039] The first valve body 53 has a bullet shape. More specifically, the base end is formed in a cylindrical shape, and the tip end is formed in a semi-spherical shape, and these are integrally connected.

[0040] The first valve seat portion 54 is inclined with respect to the axis CL so as to increase the contact area with the first valve body 53 .

[0041] The second valve body 61 has a second valve hole 61a that penetrates the center of the bottom. The second valve hole 61a is continuous with the first valve seat 54.

[0042] Further, on the outer peripheral surface of the second valve body 61 , a hydraulic pressure receiving surface portion 61 b ​​is formed which is inclined in an oblique direction with respect to the oil flowing toward the second valve body 61 .

[0043] The second valve seat portion 62 is provided with an O-ring.

[0044] A groove-shaped groove portion 26a is formed in the radial direction around the axis CL at the bottom of the valve housing member 26. A housing portion through-hole portion 26b penetrates the bottom of the valve housing member 26 from the center of the groove portion 26a along the axis CL. The inner diameter of the housing portion through-hole portion 26b is smaller than the inner diameter of the biasing member 51.

[0045] The valve guide member 27 has valve guide holes 27a at multiple locations to allow oil to pass through. The central axes of the valve guide holes 27a are oriented in the radial direction. The oil pressure receiving surface 61b of the second valve body 61 can be said to be inclined with respect to the axis of the valve guide holes 27a.

[0046] The operation of the pilot-operated switching valve 20 described above will now be described.

[0047] See FIG. 5A. When the plunger 40 is in the retracted position, the first valve body 53 and the second valve body 61 block the flow of oil toward the pressure accumulator 18 (see FIG. 1). In this case, the oil flows toward, for example, the variable spring rate mechanism. Specifically, the first valve body 53 abuts against the first valve seat 54 and the second valve body 61 abuts against the second valve seat 62 due to the biasing force of the biasing member 51. This closes the flow path R. In this case, by guiding the oil generated by the relative movement of the inner tube and the outer tube to the variable spring rate mechanism, the retracted length of the spring in the variable spring rate mechanism is shortened, and a strong spring reaction force is obtained.

[0048] See Figure 2. For example, when the variable spring rate mechanism is not to be operated, current is applied to the coil 33. When current is applied, the rod 32 moves forward and the plunger 40 is pushed out. See Figure 5B. The pushed-out plunger 40 pushes the first valve body 53 against the biasing force of the biasing member 51. This opens the previously blocked flow path R, allowing oil to flow into the pressure accumulator 18. At this time, the spring storage length of the variable spring rate mechanism does not change, and a low spring reaction force is obtained.

[0049] 5C, the first shaft portion 43d pushes the first valve body 53, causing the first valve body 53 to move away from the first valve seat portion 54. This allows oil to pass through the second valve hole portion 61a. In other words, a portion of the flow path R is opened.

[0050] 6A , when the flow path R is opened, the second valve body 61 is pushed down by the pressure difference between the hydraulic pressure on the upstream side and the hydraulic pressure on the downstream side of the second valve body 61. As the second valve body 61 is pushed down, the plunger 40 continues to move forward.

[0051] When the second valve body 61 is hydraulically pressed down until it abuts against the valve housing member 26, the first valve body 53 is also pressed down to its retraction limit by the plunger 40. This fully opens the flow path R. Oil passes from the valve guide hole 27a through the partition member hole 23a.

[0052] Furthermore, since the oil pressure receiving surface is formed at an angle to both the direction of oil flow and the direction of movement of the second valve body 61, the second valve body 61 can be reliably operated.

[0053] 6B , when the second valve body 61 fully opens the flow path R, the first shaft 43 d abuts against the first valve body 53, and the second shaft 43 c abuts against the second valve body 61. The portion of the second valve body 61 that the second shaft 43 c abuts against is tapered to match the inclined shape of the tip of the second shaft 43 c.

[0054] When the flow path R is fully open, the drive unit 30 is kept in contact with the first valve body 53 and the second valve body 61. As a result, by guiding the oil generated by the relative movement between the inner tube and the outer tube to the pressure accumulator 18, the oil is not guided to the variable spring rate mechanism, the stored length of the spring does not shorten, the spring reaction force does not become strong, and the same behavior as that of a normal suspension is obtained.

[0055] On the other hand, when the supply of current to the coil 33 (see FIG. 2) is stopped, the plunger 40 retracts. When the plunger 40 retracts, the first valve body 53 and the second valve body 61 close the flow path R due to the biasing force of the biasing member 51.

[0056] According to the pilot type switching valve 20, in the state where the flow path R is opened, the drive portion 30 is kept in contact with the second valve body 61. Next, the reason for this will be explained.

[0057] Please refer to Figure 7. Figure 7 shows the relationship between time and the position of the second valve body. Line 71 shows the results when the pilot-operated switching valve of the comparative example was used, and line 72 shows the results when the pilot-operated switching valve 20 of the embodiment (see Figure 2) was used. The horizontal axis shows time, and the vertical axis shows the position of the second valve body relative to the second valve seat.

[0058] In the pilot-operated switching valve of the comparative example, the second valve body gradually begins to open after a predetermined time T1 has elapsed since the first valve body began to open, as shown by line 71. Although the second valve body is fully opened at time T2, the second valve body vibrates due to the influence of the oil flow, and its position is unstable.

[0059] 5C, as shown by the line 72, in the pilot-operated switching valve 20 according to the embodiment, when the first valve body 53 starts to open and the predetermined time T1 has elapsed, the second valve body 61 starts to gradually open.

[0060] 6B and 7, the second valve body 61 reaches the fully open position at time T2. Since the second valve body 61 is held down by the drive unit 30, vibrations are suppressed and the position is stabilized.

[0061] The pilot-operated switching valve 20 described above will be summarized below.

[0062] See Fig. 2. First, the pilot-operated switching valve 20 includes a drive unit 30 that is actuated when energized, a first valve element 53 that opens the flow path R when the drive unit 30 is actuated, and a second valve element 61 that can open and close the flow path R together with the first valve element 53 and that, when the first valve element 53 opens the flow path R, further opens the flow path R due to the pressure difference between the upstream and downstream sides of the first valve element 53. See Fig. 6B. The drive unit 30 can also maintain the second valve element 61 in an open state when the flow path R is open.

[0063] Also see Figure 7. According to the pilot-operated switching valve 20, the drive unit 30 abuts against the second valve body 61 when the second valve body 61 is fully open. This makes it possible to suppress changes in the position of the second valve body 61 due to vibration. In other words, it is possible to provide a pilot-operated switching valve 20 that can suppress vibration of the second valve body 61.

[0064] 6B only. Secondly, the first pilot-operated switching valve 20 further includes a first valve seat 54 that abuts against the first valve body 53 when the first valve body 53 closes the flow path R. The second valve body 61 also includes a second valve hole 61a through which fluid can pass. The first valve seat 54 is formed on the periphery of the second valve hole 61a of the second valve body 61. Because the first valve seat 54 is formed on the second valve body 61, the first valve seat 54 can be formed with a small number of parts, which is preferable.

[0065] Third, in the second pilot type switching valve 20, the drive unit 30 has a first shaft 43d that is capable of passing through the second valve hole 61a and pushing the first valve body 53. In other words, the second valve hole 61a is opened on the track on which the first shaft 43d operates, and the first valve body 53 is provided. This allows the drive unit 30, the first valve body 53, and the second valve body 61 to be provided compactly, and the pilot type switching valve 20 can be made smaller.

[0066] Fourth, in the third pilot-operated switching valve 20, the drive unit 30 has a second shaft portion 43c that can abut against the periphery of the second valve hole 61a. By abutting against the periphery of the second valve hole 61a, the second shaft portion 43c can be formed in a position close to the first shaft portion 43d. This allows the drive unit 30 to be made compact, and the pilot-operated switching valve 20 to be made smaller.

[0067] Fifth, in the fourth pilot-type switching valve 20, the second shaft portion 43c has a non-circular cross section, and is in contact with the periphery of the second valve hole portion 61a, allowing fluid to pass through the second valve hole portion 61a.

[0068] 5A. Sixth, any one of the second to fifth pilot-operated switching valves 20 further includes a biasing member 51 that biases the first valve body 53 toward the first valve seat portion 54, and a second valve seat portion 62 that the second valve body 61 abuts against when the flow path R is closed. When the first valve body 53 abuts against the first valve seat portion 54 due to the biasing force of the biasing member 51, the second valve body 61 receives a biasing force in a direction in which it seats on the second valve seat portion 62. Since the first valve body 53 and the second valve body 61 are biased in the closing direction by a single biasing member 51, this can contribute to a reduction in the number of parts.

[0069] Although the shock absorber according to the present invention has been described as being applied to an inverted front fork of a motorcycle, it can also be applied to an upright front fork or rear shock absorber.Furthermore, the vehicle on which it is mounted is not limited to motorcycles, but can also be applied to saddle-ride vehicles such as tricycles and other vehicles.

[0070] Furthermore, the location where the pilot-operated switching valve is provided may be between the shock absorber body and the pressure accumulator, or between the shock absorber body and the spring rate variable mechanism, or may be in a location other than these, and the location where the pilot-operated switching valve is provided is not limited to these locations.

[0071] As long as the functions and effects of the present invention are exhibited, the present invention is not limited to the examples.

[0072] The pilot-operated switching valve of the present invention is suitable for opening and closing the flow passage of the front fork of a saddle-ride type vehicle.

[0073] 20...pilot type switching valve, 30...drive portion, 43c...second shaft portion, 43d...first shaft portion, 51...biasing member, 53...first valve body, 54...first valve seat portion, 61...second valve body, 61a...second valve hole portion, 62...second valve seat portion, R...flow path

Claims

1. A pilot-type switching valve comprising: a drive unit that is actuated when electricity is passed through it; a first valve body that opens a flow path when the drive unit is actuated; and a second valve body that is capable of opening and closing the flow path together with the first valve body, and that, when the first valve body opens the flow path, further opens the flow path due to the pressure difference between the upstream and downstream sides of the first valve body, wherein the drive unit is also capable of holding the second valve body in an open state even when it is opening the flow path.

2. A pilot-operated switching valve as described in claim 1, further comprising a first valve seat portion which the first valve body abuts when the flow path is closed, and the second valve body has a second valve hole portion through which a fluid can pass, and the first valve seat portion is formed on the periphery of the second valve hole portion of the second valve body.

3. A pilot-operated changeover valve as claimed in claim 2, wherein the drive portion has a first shaft portion capable of passing through the second valve hole portion and pushing the first valve body.

4. A pilot type changeover valve as claimed in claim 3, wherein the drive portion has a second shaft portion capable of abutting against the periphery of the second valve hole portion.

5. A pilot-operated changeover valve as claimed in claim 4, wherein the second shaft portion has a non-circular cross section and is in contact with the periphery of the second valve hole portion to allow fluid to pass through the second valve hole portion.

6. A pilot-operated changeover valve as described in claim 2, further comprising: a biasing member that biases the first valve body toward the first valve seat portion; and a second valve seat portion against which the second valve body abuts when the second valve body closes the flow path, wherein when the first valve body abuts against the first valve seat portion due to the biasing force of the biasing member, the second valve body is biased in a direction such that it seats on the second valve seat portion.

7. A shock absorber having a pilot type switching valve as described in claim 1, comprising: a telescopic outer tube and an inner tube; and a pressure accumulator provided in the outer tube or the inner tube and capable of storing oil, wherein the flow path of the pilot type switching valve is a portion connecting the inside of the inner tube and the pressure accumulator.

Images