JPH11218176A - Shock absorber and leaf valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase freedom of design of a shock absorber provided with a valve comprising leaf valves. SOLUTION: During elongation of a piston rod, three leaf valves 102, 104, 106 are bent. During contraction, one leaf valve 106 is bent in the small state of force acting upon a shock absorber, and three leaf valves 102, 104, 106 are bent in the large state of the force. Larger damping force can therefore be generated during elongation than during contraction, and during contraction, small damping force can be controlled even if acting force is small. In this shock absorber, freedom of design of a damping characteristic can be thus increassed, and freedom of design of the shock absorber can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a shock absorber including a leaf valve.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 62-114239 discloses that
As an example of the above-described shock absorber, a cylinder body, a piston that partitions the inside of the cylinder body into two chambers, and increases and decreases the volume of the two chambers with the operation of the shock absorber, and a piston rod fixed thereto, There is described a shock absorber including a valve that allows a flow of hydraulic fluid from a high-pressure chamber having a higher pressure to a low-pressure chamber having a lower pressure among the two chambers. This valve includes two leaf valves stacked in the thickness direction. In this valve,
Regardless of the operating state of the shock absorber, the two leaf valves bend together. Therefore, the degree of freedom in designing the shock absorber is not sufficient, and it is difficult to design a shock absorber having a desired damping characteristic.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to increase the degree of freedom in designing a shock absorber provided with a valve having a leaf valve. According to the present invention, the following shock absorber and leaf valve are obtained. In addition, each mode is divided into items, item numbers are assigned, and if necessary, the numbers of other items are cited and described in the same format as the claims. This is to clarify the possibility of adopting the features described in each section in combination. (1) A cylinder body, a piston for partitioning the inside of the cylinder body into two chambers, and increasing or decreasing the volume of the two chambers with the operation of the shock absorber, a piston rod fixed thereto, and a piston rod for the two chambers. A valve that permits the flow of the hydraulic fluid from the high-pressure chamber of the higher pressure to the low-pressure chamber of the lower pressure, wherein the valve includes a leaf valve in which a plurality of stacked valves are stacked, and A shock absorber characterized in that the number of bent leaf valves varies depending on the state. As described above, in the valve provided in the shock absorber described in this section, the number of bent leaf valves varies depending on the operating state of the shock absorber. Usually, when the number of flexures is small, the valve is more easily flexed than when the number is large. For this reason, the valve opening pressure of the valve decreases, and the damping coefficient of the damping force generated in the valve (the amount of increase in the damping force with respect to the amount of increase in the relative movement speed of the piston rod with respect to the cylinder body) decreases. If designed so that the number of flexures is different,
Since the attenuation characteristics can be made different, the degree of freedom in designing the attenuation characteristics can be increased. Each of the plurality of leaf valves in the present specification may be one that bends at least at one of the operation times of the shock absorber, and does not necessarily bend when the shock absorber is operated. For example, if the piston rod does not bend in the contracted state in which the piston rod is contracted with respect to the cylinder body, but bends in the extended state in which the piston rod is extended, it is a leaf valve. For this reason, a leaf valve that satisfies the above-described conditions even if it does not sit and separate from the valve seat of the valve is used. For example, the valve may include three annular plate-like members, an inner peripheral valve seat provided on one of the two chambers, and an outer peripheral valve seat provided on the other chamber. When the hydraulic pressure of the other chamber is higher than the hydraulic pressure of the one chamber, only one of the three annular plate-shaped members located on the side of the one chamber is bent, and one of the three annular plate-shaped members is bent. When the hydraulic pressure in the chamber is higher than the hydraulic pressure in the other chamber, all three annular plate members can be bent. When the fluid pressure in the other chamber is higher than the fluid pressure in the one chamber, the outer peripheral portion is bent while the inner peripheral edge of the one plate member is pressed against the inner peripheral valve seat. As a matter of course, the outer peripheral portion is not seated and separated from the outer valve seat, but is seated and separated from the intermediate plate member located in the middle. However, the one-side plate-like member is a leaf valve because it satisfies the condition that the one-side plate-like member bends at least at one time of the operation time of the shock absorber. Similarly, the other plate-shaped member located on the other chamber side cannot be seated or separated from the inner peripheral valve seat when the inner peripheral portion is bent, but the one that satisfies the above-described conditions. Therefore, it is a leaf valve. The intermediate plate-shaped member is a leaf valve, although it is not seated or separated from the outer peripheral valve seat or the inner peripheral valve seat. The operating state may be, as described later in (4), whether the hydraulic pressure difference between the high-pressure chamber and the low-pressure chamber is small or large, or the valve may be operated as described in (2) below. However, if the flow of the hydraulic fluid is permitted during both extension and contraction of the piston rod, as described with respect to the item (3),
The operating state can be elongating or contracting. (2) The shock absorber according to (1), wherein the valve allows the flow of the hydraulic fluid in both a state where the piston rod is extended and a state where the piston rod is contracted. In the shock absorber described in this section, the valve allows the flow of the hydraulic fluid during the extension and the contraction of the piston rod. Therefore, it is not necessary to provide both a valve for extension allowed during extension and a valve for contraction allowed during contraction, and the structure of the shock absorber can be simplified accordingly. (3) The shock absorber according to item (2), wherein the number of leaf valves that bends varies depending on whether the piston rod is being extended or contracted. In the shock absorber described in this section, the damping characteristics can be made different between during extension and during contraction, and the magnitude of the damping force generated when the relative movement speed of the piston rod to the cylinder body is different is different. Can be made. The number of flexures may be larger during extension or contraction, but it is generally desirable that the damping force generated during extension is larger than that during contraction. It is desirable that the number be larger than the number of sheets that bends during contraction. For example, some of the leaf valves may flex during contraction, and all leaf valves may flex during extension. When the valve includes three leaf valves, the number of leaf valves that bends during contraction is one or two,
The number of flexures during extension can be two or three. (4) The number of leaf valves that bend varies depending on the operating state of the hydraulic pressure difference between the high-pressure chamber and the low-pressure chamber of the shock absorber. The shock absorber according to any one of the above. In the shock absorber described in this section, when the hydraulic pressure difference between the high-pressure chamber and the low-pressure chamber is small and large,
The attenuation characteristics can be different. By reducing the number of sheets that bend when the hydraulic pressure difference is small, the leaf valve can be bent while the force acting on the shock absorber is small, and a small damping force can be controlled.
A valve with a low valve opening pressure can be obtained. When the shock absorber described in this section is combined with the shock absorber described in section (3), the degree of freedom in designing damping characteristics can be further increased. For example, in the case where the valve includes three leaf valves, the number of flexures during extension is set to three, and the number of contractions is set to one. Number 1
The number of sheets may be two or three when the number is large. (5) The plurality of leaf valves include a selected bending leaf valve that bends or does not bend according to the operation state of the shock absorber and a non-selection bending leaf valve that bends regardless of the operation state. The shock absorber according to any one of paragraphs (4) to (4). In the valve of the shock absorber described in this section, the non-selective bending leaf valve bends, or the non-selective bending leaf valve and the selective bending leaf valve bend in accordance with the operation state of the shock absorber. In some cases, the non-selective bending leaf valve and at least one of the plurality of selective bending leaf valves may be bent. When a plurality of leaf valves are stacked in the thickness direction, of the plurality of leaf valves,
One or more leaf valves including the outermost leaf valve located on the outermost side on one side in the thickness direction are non-selected flexible leaf valves, and all non-selected flexible leaf valves are excluded from the leaf valves. Can be a selective bending leaf valve. (6) The selective bending leaf valve is provided with pressure guiding means for guiding the hydraulic pressure in the chamber of the two chambers on the side opposite to the side where the non-selective bending leaf valve is located to the non-selective bending leaf valve. The shock absorber according to item (5). The hydraulic pressure of the chamber (the other chamber) on the side (the other side) opposite to the side (the one side) where the non-selected flexible leaf valve is located is guided to the non-selected flexible leaf valve by the pressure guiding means. The other side surface of the non-selective flexible leaf valve (if there is one or more non-selective flexible leaf valves, the other side of the leaf valve located on the other side of the one or more non-selective flexible leaf valves) (Hereinafter, abbreviated similarly), the hydraulic pressure of the other chamber guided by the pressure guiding means acts, and the hydraulic pressure of the one chamber acts on the one side surface. If the hydraulic pressure acting on the other surface is greater than the hydraulic pressure acting on the one surface by more than the hydraulic pressure difference (valve opening pressure) required for the non-selective flex leaf valve to flex, the non-select flex leaf valve flexes. Can be (7) The shock absorber according to (6), wherein the pressure guiding means includes one or more pressure guiding paths formed through one or more selective bending leaf valves in the thickness direction. In the shock absorber described in this section, the hydraulic pressure in the other chamber is 1
The non-selective flexible leaf valve is guided to the non-selective flexible leaf valve via a pressure guide path formed by a group of through holes provided in each of the one or more selective flexible leaf valves, and acts on the surface on the other side.
Through-holes in the thickness direction are formed in each of the selective bending leaf valves, and if these selective-flexing leaf valves are overlapped with each through-hole communicating with each other, hydraulic pressure is formed by the plurality of through-holes. It is guided by the pressure passage and acts on the selective deflection leaf valve. Even if the cross-sectional area is uniform in the axial direction, the impulse path has a small area with a small cross-sectional area and a large area with a large cross-sectional area. (A small-diameter portion), but the portion of the pressure guide path adjacent to the non-selective flexible leaf valve is desirably a large-area portion. This is because if the area is large, the hydraulic pressure in the other chamber can be satisfactorily applied to the non-selective bending leaf valve. That is, in the case where the number of the selective bending leaf valve is one, the through hole in the thickness direction formed in the one selective bending leaf valve has a large area even if the cross-sectional area is uniform. It may have a small area portion, and in the case of a plurality, the sectional areas of the through holes formed in each of the plurality of selective bending leaf valves may be the same or different. Even when a plurality of selective bending leaf valves are included, the through-hole formed in one leaf valve may have a shape having a large area portion and a small area portion. The number of leaf valves that bend according to the operating state can be determined by the cross-sectional area of the pressure guiding path. When the pressure guide path has a uniform and large cross-sectional area, and the hydraulic pressure in the other chamber is higher than the hydraulic pressure in one chamber, even if the operating speed of the shock absorber is small or large, In a state where only the non-selective flexible leaf valve is bent and the hydraulic pressure in one chamber is higher than the hydraulic pressure in the other chamber, the non-selective flexible leaf valve and the selective flexible leaf valve bend together. If the hydraulic pressure in the other chamber is higher than the hydraulic pressure in one chamber, the hydraulic pressure in the other chamber is directed through the pressure path and acts on the other side of the non-selective flex leaf valve; The non-selective bent leaf valve is bent to generate a flow of the hydraulic fluid in the pressure guide path. However, if the cross-sectional area of the pressure guide path is large, the hydraulic fluid is allowed to flow at a sufficient flow rate. No substantial hydraulic pressure difference occurs on both sides of the valve, and the selective bending leaf valve does not bend. On the other hand, when the pressure guide path has a small area and a large area formed in a portion adjacent to the non-selective bending leaf valve, the small area is formed. The number of flexures is determined by the position according to the operation state. When the hydraulic pressure in the other chamber is higher than the hydraulic pressure in the one chamber, only the non-selective bending leaf valve is bent when the operating speed of the shock absorber is low, and a small area is formed when the operating speed is high. The selected flexible leaf valve and the selective flexible leaf valve located on the side of one of the chambers also flex. When the hydraulic pressure difference increases, the flow of the hydraulic fluid in the small area portion is suppressed, so that the hydraulic fluid cannot flow at a sufficient flow rate. for that reason,
A hydraulic pressure difference occurs before and after the selective bending leaf valve, and the selective bending leaf valve also bends. The non-selective flexible leaf valve, the selective flexible leaf valve having a small area, and the selective flexible leaf valve located on one side of the chamber are bent. In this manner, the number of leaf valves that bend according to the operation state can be determined based on the size of the cross-sectional area of the pressure guiding path, the position in the thickness direction of the selected leaf valve where the small area portion is formed, and the like. . When the hydraulic pressure of the other chamber is higher than the hydraulic pressure of the one chamber, in a state where only the non-selective bending leaf valve is bent, the hydraulic fluid is supplied to the pressure guide path, the selective bending leaf valve and the non-selective bending leaf valve. Flows through the gap between the leaf valve and the valve seat of the valve in addition to the above-described path in a state where the non-selective bending leaf valve and the selective bending leaf valve are bent. . In the former case, when the impulse path has a small area, the orifice characteristic is obtained after the non-selective bent leaf valve is bent, and in a state where all the leaf valves are bent, Only the valve characteristics are obtained.
Also, when the hydraulic pressure in one chamber is higher than the hydraulic pressure in the other chamber and all leaf valves are bent, only valve characteristics are obtained. (8) The valve includes three leaf valves stacked in a thickness direction, wherein the three leaf valves are a main bending leaf valve located on any one side in the thickness direction, and Including a throttle leaf valve having a small cross-sectional area through-hole located on the other side in the thickness direction, and a pressure guiding leaf valve intermediately having a large cross-sectional area through hole
The shock absorber according to any one of paragraphs (1) to (7). When the hydraulic pressure in the other chamber becomes higher than the hydraulic pressure in one chamber due to the operation of the shock absorber, the hydraulic fluid in the other chamber passes through the small-area through-hole and the large-area through-hole. Guided and acts on the other side surface of the main flex leaf valve. On the other hand, the hydraulic pressure in one chamber acts on one surface of the main flexible leaf valve. If the hydraulic pressure in the other chamber is higher than the hydraulic pressure in the one chamber by more than the hydraulic pressure difference required for the main flexure leaf valve to flex, the main flexure leaf valve flexes and the flow of hydraulic fluid is allowed. If the main bending leaf valve is easily bent, the valve will be opened even if the hydraulic pressure difference between the other chamber and the one chamber is small (even if the force acting on the shock absorber is small). The force acting on the shock absorber increases (the operating speed of the shock absorber increases), and the hydraulic pressure in the other chamber acting on the other surface of the throttle leaf valve acts on the one surface. When the hydraulic pressure in the chamber becomes larger than the hydraulic pressure difference required for the two leaf valves for throttling and pressure guiding to bend, the two leaf valves are bent together. In this state, as a result, all three leaf valves bend. Conversely, the hydraulic pressure in one chamber acting on the main flexure leaf valve is greater than the fluid pressure in the other chamber acting on the throttle leaf valve, and the hydraulic pressure difference (valve opening pressure) required for the three leaf valves to flex. If it is higher, the three leaf valves will bend together. In addition, instead of having the through-hole having a large cross-sectional area, the pressure-guiding leaf valve located in the middle has a shape and dimensions that do not block the through-hole with a small cross-sectional area formed in the restrictor leaf valve. Can achieve a similar effect. (9) The valve according to any one of (1) to (4), wherein the valve includes two leaf valves, and one of the leaf valves and a part of the other leaf valve are overlapped. Shock absorber. In the shock absorber described in this section, the other leaf valve has a portion overlapping with one leaf valve and a portion not overlapping. Therefore, the other leaf valve 1 depends on the operating state.
The leaf valves may be deflected, or one and the other two leaf valves may be deflected. (10) A cylinder body, a piston for partitioning the inside of the cylinder body into two chambers, and increasing and decreasing the volume of the two chambers with the operation of the shock absorber, a piston rod fixed thereto, and a piston rod for the two chambers. A valve that permits the flow of hydraulic fluid from the high-pressure chamber with the higher pressure to the low-pressure chamber with the lower pressure, wherein the damping characteristic of the damping force generated in the valve is in the operating state. Shock absorber that changes according to. In the valve, if the number of bent leaf valves differs according to the operation state, the damping characteristic changes. The valve described in this section can be, for example, the valve described in any one of the above-mentioned paragraphs (1) to (9). (11) a cylinder body, a piston that partitions the interior of the cylinder body into two chambers, and increases or decreases the volume of the two chambers with the operation of the shock absorber, and a piston rod fixed thereto; and the two chambers. A hard valve that allows the flow of hydraulic fluid from the high-pressure chamber to the low-pressure chamber when the hydraulic pressure difference between the high-pressure chamber having a higher pressure and the low-pressure chamber having a lower pressure is large; and A shock absorber including a soft valve that allows a flow of hydraulic fluid from a high-pressure chamber to a low-pressure chamber from a state where a pressure difference is small, and a liquid passage having a throttle function provided in parallel with the hard valve, wherein At least one of the valve and the hard valve includes a plurality of stacked leaf valves, and the number of leaf valves that bends according to the operation state of the shock absorber. Shock absorbers with different numbers. A valve having a different number of leaf valves that bends according to the operation state of the shock absorber may be applied to a hard valve, a soft valve, or both. In the absorber, since a hard valve bypass passage having a throttle function is provided in parallel with the hard valve, it is desirable to apply the invention to a soft valve. At least one of the hard valve and the soft valve is as described in the above items (2) to (9).
It can be any one of the valves described in the section.
Further, the hard valve and the soft valve may be valves of the same mode, or may be valves of different modes.
Any combination of the two valves described in (9) can be used. (12) When the hard valve and the soft valve are in both the extended state and the contracted state of the piston rod,
The hard valve and the soft valve allow the flow of the hydraulic fluid from the high-pressure chamber to the low-pressure chamber, and each of the hard valve and the soft valve is a portion of one of the two chambers of the piston on the side of one of the two chambers. Is provided on the side of the room
The liquid passage is provided inside the piston and opens to a chamber on the side where the hard valve is provided, and to a liquid passage between the hard valve and the soft valve.
The shock absorber according to (11). Because a hard valve and a soft valve are provided on both sides of the piston,
The size of the piston can be reduced. (13) A leaf valve for a shock absorber valve, wherein the leaf valve has an annular plate shape and has a through hole penetrating in a thickness direction at a portion between an outer peripheral edge and an inner peripheral edge. ). For example, the throttle leaf valve and the pressure guiding leaf valve described in the above (8) correspond to the leaf valve of the present embodiment. (14) The leaf valve according to (13), wherein the through-hole has a cross-sectional area large enough to perform a throttle function, and is bent by a pressure difference generated before and after the through-hole at least one time during the operation of the shock absorber. This leaf valve can be referred to as a throttle leaf valve. (15) The leaf valve according to (13), wherein the through-hole has a cross-sectional area having a size that does not substantially perform the throttle function at any time during the operation of the shock absorber. This leaf valve can be referred to as a pressure guiding leaf valve.

[0004]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A shock absorber according to an embodiment of the present invention will be described in detail with reference to the drawings. The shock absorber is one of the components of the suspension. As shown in FIG. 3, the cylinder body 10 of the shock absorber is attached to the wheel member 12 via a bracket, and the piston rod 14 is attached to the vehicle body member 16. The spring 18 is provided between the upper seat 22 and the lower seat 20 attached to the cylinder body 10.

As shown in FIGS. 1 and 2, the shock absorber includes the cylinder body 10, the piston rod 14, the piston 28, the damping force control device 30, and the like.
The piston rod 14 penetrates through the piston 28, and is fixed at its end by a nut, so that the piston 28 and the piston rod 14 can be integrally moved. The piston 28 is liquid-tight and slidable with respect to the cylinder body 10, and the interior of the cylinder body 10 is partitioned into a lower chamber 34 and an upper chamber 36 by the piston 28.

The damping force control device 30 includes a hard valve 4
0, a soft valve 42, a variable throttle device 44, and the like. A hard valve 40 is provided on the lower chamber side of the piston 28, a soft valve 42 is provided on the upper chamber side, and an intermediate liquid passage 46 is provided between the hard valve 40 and the soft valve 42. Further, a through hole 48 extending in the axial direction and having an opening in the lower chamber 34 is provided inside the piston rod 14, and a spool 50 is slidably disposed in the through hole 48. A plurality of radial holes 52 extending in the radial direction are formed in a portion of the piston rod 14 corresponding to the intermediate liquid passage 46, so that the intermediate liquid passage 46 and the through hole 48 communicate with each other. The lower chamber 34 and the intermediate liquid passage 46 are connected by the through hole 48 and the radial hole 52, bypassing the hard valve 40. Lower chamber 34 of through hole 48 provided in piston rod 14
A hard valve bypass passage 54 is formed by the portion between the fluid passage 46 and the intermediate liquid passage 46, the radial hole 52, and the like.
As the spool 50 moves in the axial direction, the opening area of the radial hole 52 is controlled, and the flow area of the hard valve bypass passage 54 is controlled.

The variable throttle device 44 is provided with the spool 50
And a moving device 56 for moving the spool 50 in the axial direction. The moving device 56 includes an electric motor 60.
And a motion conversion mechanism 62 that converts the rotational motion of the electric motor 60 into a linear movement in the axial direction, and a shaft 64 that is movable in the axial direction. When the electric motor 60 is rotated, the rotation is converted into the axial movement of the shaft 64 by the movement conversion mechanism 62, and the axial movement of the shaft 64 causes the spool 50 to move in the axial direction.
Thus, in the present embodiment, the hard valve 4
0, a soft valve 42 and a hard valve bypass passage 54 are provided in the piston 28, and a variable throttle device 44 for controlling the flow area of the hard valve bypass passage 54 is provided inside the piston rod 14. In the middle of the piston rod 14, a rebound stopper 7
0 is attached, and the extension limit of the piston rod 14 is defined.

As shown in FIG. 4, the hard valve 40 includes a valve seat 80 provided below the piston 28, a leaf valve 82 having a generally annular thin plate shape, and an inner peripheral side of the leaf valve 82. A positioning member 84 for determining the radial position of the leaf valve 82;
And an intermediate sheet member 86 provided on the upper surface side (the side facing the intermediate liquid passage 46) of the inner peripheral edge of the second sheet member 2. Since the intermediate side sheet member 86 is in contact with the piston body via the spacer 88, the differential pressure acting force corresponding to the differential pressure between the lower chamber 34 and the intermediate liquid passage 46 applied to the leaf valve 82. It is possible to receive. An annular groove 90 and a liquid passage 91 to the plurality of lower chambers 34 are formed in the piston 28, and the periphery of the groove 90 is a valve seat 80 as a chamber-side seat. as a result,
The leaf valve 82 is elastically deformed by the valve seat 80 and the intermediate side seat member 86 with the upper surface 92 of the leaf valve 82 facing the intermediate liquid passage 46 and the lower surface 94 facing the lower chamber 34. Supported. Leaf valve 82
When the pressure difference between the intermediate liquid passage 46 and the lower chamber 34 becomes greater than a set pressure (hard valve opening pressure), the valve is bent and the hard valve 40 is opened.

When the fluid pressure in the lower chamber 34 is higher than the fluid pressure in the intermediate fluid passage 46 by more than the valve opening pressure, the inner peripheral edge of the leaf valve 82 is pressed against the intermediate seat member 86, and The outer peripheral portion is bent with the edge of the fulcrum as a fulcrum. When the fluid pressure of the intermediate fluid passage 46 is higher than the fluid pressure of the lower chamber 34 by more than the valve opening pressure, the outer peripheral edge is pressed against the valve seat 80, and the inner peripheral portion is supported by the outer peripheral edge as a fulcrum. Is deflected. Here, in the leaf valve 82, the inner peripheral portion is less likely to bend than the outer peripheral portion. The valve opening pressure of the hard valve 40 is larger when the inner peripheral portion is flexed, and the damping force generated when the inner peripheral portion is flexed is that the outer peripheral portion is flexed. Than in the case where
It increases when the relative movement speed of the piston rod 14 with respect to the cylinder body 10 is the same. It is more difficult for the piston rod 14 to open during extension than during contraction,
The damping force generated in the shock absorber is
It is to be bigger.

As shown in FIGS. 5 and 6, the soft valve 42 includes a valve seat 100 provided on the piston 28 and three annular thin plate-shaped leaf valves 102, 104, and 106.
, A positioning member 110 and a room-side sheet member 112. The chamber side seat member 112 is brought into contact with the piston rod 14, and the leaf valves 102, 10
It is possible to receive a differential pressure acting force acting on 4,106. An annular groove 114 is formed in the piston 28, and the groove 114 and the intermediate liquid passage 46
6 communicate with each other. The outer peripheral edge of the groove 114 is the valve seat 100. In the soft valve 42, three leaf valves 102, 104 and 106 are stacked in the axial direction. The leaf valve 102 located closest to the intermediate liquid passage 46 has a small-diameter axial through hole 12.
0 are formed along the circumference of substantially the same radius, and the leaf valve 106 located closest to the upper chamber 36 side.
Is thin and easy to bend, and the leaf valve 104 located in the middle has a plurality of large-diameter through holes 122 formed therein. Two leaf valves 102 and 104
Is a state in which the small-diameter through-hole 120 and the large-diameter through-hole 122 are located in the same phase, that is, the through-holes 120 and 12
2 are arranged in a state where they are communicated with each other. An orifice is formed by the small-diameter through-hole 120, and the large-diameter through-hole 122 enables the hydraulic pressure of the intermediate liquid passage 46 to be transmitted well to the surface 124 of the leaf valve 106 on the intermediate hydraulic pressure chamber side. The hydraulic pressure in the intermediate liquid passage 46 passes through the small-diameter through-hole 120 and the large-diameter through-hole 122 to the leaf valve 106.
Is transmitted to A pressure guiding path is formed by the through holes 120 and 122.

As shown in FIG. 7, when the fluid pressure in the intermediate fluid passage 46 is higher than the fluid pressure in the upper chamber 36, the fluid pressure in the intermediate fluid passage 46 is increased through the through holes 120 and 122, and the leaf valve 10 is turned on.
6 and is guided to the surface 124 on the side of the intermediate liquid passage and acts. On the other hand, the hydraulic pressure of the upper chamber 36 acts on the upper surface 126 of the leaf valve 106. When a substantial difference in hydraulic pressure between the two surfaces 124 and 126 of the leaf valve 106 is equal to or greater than a magnitude (valve opening pressure) required for the leaf valve 106 to bend, the inner peripheral edge of the leaf valve 106 is The sheet is pressed against the sheet member 112, and the outer peripheral portion is bent upward. The working fluid in the intermediate fluid passage 46 is supplied to the small diameter through hole 12
0, large diameter through hole 122, leaf valves 104 and 106
Through the gap between the upper chamber 36 and the upper chamber 36. Since the leaf valve 106 is easily bent, even if the hydraulic pressure difference between the intermediate liquid passage 46 and the upper chamber 36 is small, the leaf valve 106 is bent and the flow of the hydraulic fluid is allowed. In this case, a damping force having an orifice characteristic is generated.

Thereafter, when the hydraulic pressure difference between the intermediate liquid passage 46 and the upper chamber 36 increases, the flow of the hydraulic fluid flows through the through hole 120.
, It cannot flow at a sufficient flow rate. Therefore, the hydraulic pressure of the intermediate liquid passage 46 acts on the surface 128 of the leaf valve 102 on the side of the intermediate liquid passage. On the other hand, a hydraulic force corresponding to the hydraulic pressure of the upper chamber 36 acts on the upper chamber side surface 130 of the leaf valve 104. The intermediate liquid passage 46 acting on the surface 128 of the leaf valve 102
Is different from the hydraulic pressure of the upper chamber 36 acting on the surface 130 of the leaf valve 104.
When the hydraulic pressure difference required for bending of the valve 4 becomes equal to or larger than that, the outer peripheral portions of the leaf valves 102 and 104 are both bent upward. The flow of the hydraulic fluid from between the leaf valve 102 and the valve seat 100 is also allowed, and a damping force of the valve characteristics is generated. As shown in the figure, the hydraulic fluid is supplied to the through holes 120 and 12.
2. It can flow through the gap between the leaf valves 106 and 104, and can flow through the gap between the leaf valves 102 and 104.

As described above, when the fluid pressure in the intermediate fluid passage 46 is higher than the fluid pressure in the upper chamber 36, when the fluid pressure difference between the intermediate fluid passage 46 and the upper chamber 36 is small, the leaf valve 106 Only the leaf valves 102, 104 are flexed if they are large. As described above, the number of flexures differs between a case where the hydraulic pressure difference is small and a case where the hydraulic pressure difference is large, so that damping forces having different damping characteristics are generated. In addition, since the leaf valve 106 is easy to bend, there is an advantage that the hydraulic pressure difference is very small, the flow of the hydraulic fluid is allowed in a state where the operating speed of the shock absorber is very small, and the damping force can be controlled.

On the other hand, when the hydraulic pressure in the upper chamber 36 is higher than the hydraulic pressure in the intermediate liquid passage 46, the leaf valves 102, 104, 10
When the hydraulic pressure difference (valve opening pressure) required for bending of the valve 6 increases, the outer edges of the leaf valves 102, 104, and 106 are pressed against the valve seat 100, and the inner circumference of the leaf valves 102, 104, and 106 is bent downward. Can be In this case, three leaf valves 1
02, 104, and 106 are flexed together, the resistance applied to the hydraulic fluid increases, and a damping force of valve characteristics is generated.

As shown in FIG. 8, in the soft valve 42, when the fluid pressure in the intermediate fluid passage 46 is higher than the fluid pressure in the upper chamber 36, and when the fluid pressure difference is small, a damping force of the orifice characteristic is generated. When the hydraulic pressure difference is large, a damping force having valve characteristics is generated. When the hydraulic pressure in the upper chamber 36 is higher than the hydraulic pressure in the intermediate liquid passage 46, the three leaf valves 102, 104, and 106 are flexed together, so that the damping is greater than when one leaf valve is flexed. Force is generated. In this case, both the valve opening pressure and the damping coefficient increase.

The electric motor 60 is controlled by a controller 130. By controlling the electric motor, the flow passage area of the hard valve bypass passage 54 is controlled, and the damping force is controlled. In the shock absorber configured as described above, the force acting on the shock absorber is small, and the hydraulic fluid does not flow from the high-pressure chamber to the low-pressure chamber before the soft valve 42 is opened. The force acting on the shock absorber increases, and the soft valve 42
Is opened, the hydraulic fluid is caused to flow through the soft valve 42, the intermediate fluid passage 46, and the hard valve bypass passage 54, and becomes larger. When the hard valve 40 is opened, a part of the hydraulic fluid is 42, intermediate liquid passage 4
6, it is made to flow through the hard valve 40.

When the distance between the vehicle body-side member 16 and the wheel-side member 12 becomes small, a downward force acts on the piston 28, and a force for contracting the piston rod 14 acts.
When the force acting on the shock absorber is small, the hard valve 40 is not opened, but in the soft valve 42, only the leaf valve 106 is bent, and the flow of the hydraulic fluid is allowed. When the soft valve 42 is opened, the working fluid flows through the hard valve bypass passage 54, the intermediate liquid passage 46, and the soft valve 42. When the force acting on the shock absorber increases, the leaf valves 102 and 104 also bend. When the size becomes even larger, the leaf valve 82 is bent in the hard valve 40, and the flow of the hydraulic fluid is allowed. Some hydraulic fluids
Hard valve 40, intermediate liquid passage 46, soft valve 42
Will flow through. When the distance between the vehicle body-side member 16 and the wheel-side member 12 increases, an upward force acts on the piston 28, and a force for extending the piston rod 14 acts. During the extension, the flow of the hydraulic fluid is permitted by bending the leaf valves 102, 104, and 106 in the soft valve 42, and the flow is permitted by bending the leaf valve 82 in the hard valve 40. Is done.

In the shock absorber according to the present embodiment, the damping force is generated as shown in FIG. Since three leaf valves are flexed by the soft valve 42 during extension, the valve opening pressure is greater and the damping coefficient is greater than during contraction. Further, during contraction, when the force acting on the shock absorber is small and the hydraulic pressure difference between the intermediate liquid passage 46 and the upper chamber 36 is small, the leaf valve 106 is bent, and the flow of the hydraulic fluid is allowed. You. As described above, in the present embodiment, in the soft valve 42, the number of flexures can be varied depending on whether the piston rod 14 is expanding or contracting, when the hydraulic pressure difference is small, or when the piston rod 14 is large. The degree of freedom described above can be increased, and the degree of freedom in setting the shock absorber can be increased. The leaf valves 102 and 104 included in the soft valve 42 are the leaf valves according to one embodiment of the present invention.

The soft valve is not limited to the soft valve 42 in the above-described embodiment, but may be in the form shown in FIGS. The soft valve 150 is
Like the soft valve 42, the three leaf valves 15
2, 154, and 156, but the leaf valve 154 located in the middle has an outer diameter of the leaf valve 152.
The size is such that the small-diameter through hole 158 formed in the hole is not closed. Since the small-diameter through hole 158 is provided along a circumference having substantially the same radius, the outer diameter of the leaf valve 154 is smaller than that radius. Further, as in the case of the above embodiment, an annular groove 160 is formed in the piston 28, and the outer peripheral edge thereof is the valve seat 162, but the outer peripheral edge protrudes from the inner peripheral edge. Have been allowed. The outer peripheral edge of the leaf valve 152 supported by the valve seat 162 is bent upward, pressed against the outer peripheral edge of the leaf valve 156, and brought into close contact. Since the outer diameter of the leaf valve 154 is smaller than the outer diameter of the leaf valves 152 and 156, the outer peripheral edges of the leaf valves 152 and 156 are brought into contact with each other in a non-operating state of the shock absorber. The flow of hydraulic fluid is avoided.

As shown in FIG. 12, when the liquid pressure in the intermediate liquid passage 46 is higher than the liquid pressure in the upper chamber 36, the intermediate liquid passage 46
Of the through hole 158, the leaf valves 152 and 154
Through the gap between the intermediate liquid passages 46 of the leaf valve 156.
Acts on the side surface. The upper chamber 3 of the leaf valve 156
The hydraulic pressure of the upper chamber 36 acts on the surface on the sixth side. When the hydraulic pressure difference becomes equal to or greater than the hydraulic pressure difference (valve opening pressure) required to flex the leaf valve 156, the outer peripheral portion of the leaf valve 156 is flexed upward, and the damping force of the orifice characteristic is reduced. Generated. Further, if the difference between the hydraulic pressures acting on the surface of the leaf valve 152 on the intermediate liquid passage 46 side and the surface on the upper chamber 36 side becomes greater than the hydraulic pressure difference required to bend the leaf valves 152 and 154, respectively. , Leaf valves 152, 15
4 are both bent upward to generate a damping force having valve characteristics. When the hydraulic pressure of the upper chamber 36 becomes higher than the hydraulic pressure of the intermediate liquid passage 46 by a hydraulic pressure difference (valve opening pressure) required for the leaf valves 152, 154, and 156 to bend, the leaf valve 1
52, 154, and 156, the inner peripheral portions are both bent downward. During extension, three leaf valves 15
Since 2,154 and 156 are bent, the valve opening pressure is large and the damping coefficient is large. Note that the leaf valve 152
Is a leaf valve according to an embodiment of the present invention.

The soft valve may be a soft valve 180 shown in FIG. Soft valve 18
0 includes three leaf valves 182, 184 and 186, but the through hole 188 formed in the leaf valve 182 located on the intermediate liquid passage 46 side is relatively large,
The pressure guide path does not have a throttle function. Therefore, 1
When the leaf valves 186 are bent,
The hydraulic fluid flows through the through holes 188 and 190, and the generated damping force has valve characteristics instead of orifice characteristics. Further, since the through hole 188 is large enough to allow a large flow of the hydraulic fluid, even if the hydraulic pressure difference becomes large, the three leaf valves 182, 184, and 186 are not bent together. Only one leaf valve 186 bends. As described above, one leaf valve 186 is flexed during the contraction of the piston rod 14, and three leaf valves 182, 184, 186 are flexed together during the extension. Similar effects can be obtained even if the outer diameter of the leaf valve 184 is smaller than the radius at which the through hole 188 formed in the leaf valve 182 is formed. Further, as shown in the drawing, it is not essential to provide a positioning member corresponding to each of the leaf valves 182, 184, 186, and one positioning member may be provided as in the above embodiment.

The soft valve may be a soft valve 200 shown in FIG. Soft valve 2
00, the two leaf valves 202 and 204
The inner diameter is almost the same and the outer diameter is different, and the entire leaf valve 204 and a part of the leaf valve 202 are overlapped. The soft valve 200 is a leaf valve 20
2 and 204, and also includes positioning members 206 and 208, and the leaf valve 2 located on the intermediate liquid passage 46 side.
02 is positioned by the positioning member 206, and the leaf valve 204 located on the upper chamber 36 side is positioned by the positioning member 208.
Reference numeral 8 also functions as the upper chamber side seat member of the leaf valve 202. The upper chamber side seat member of the leaf valve 204 is the piston rod 14. As shown in FIG. 15, while the piston rod 14 is contracted, the leaf valves 202 and 204 are both flexed, but during extension, the leaf valve 204 is hardly flexed, and only the leaf valve 202 is flexed. Will be
The number of leaf valves that bend during contraction and during extension is different. During extension, leaf valves 202 and 2
04, the hydraulic fluid enters between the leaf valve 20
2, a hydraulic pressure difference occurs between both surfaces, and only the leaf valve 202 bends.

It should be noted that one or more notches can be provided at the outer peripheral edges of the positioning members 206 and 208. If the notch is provided, the flow of the hydraulic fluid can be allowed at a sufficient flow rate in the early stage of the valve opening. Also, the leaf valve 204 is
The hydraulic pressure transmitting portion 228 and the plurality of through holes 23 shown in FIG.
It may be a leaf valve 232 containing zero. The hydraulic pressure in the upper chamber 36 is transmitted favorably to the surface of the leaf valve 202 on the upper chamber 36 side through the through hole 230 and the hydraulic pressure transmitting section 228. When the hydraulic pressure difference generated on both surfaces of the leaf valve 202 becomes equal to or more than the valve opening pressure, the leaf valve 204 does not bend, and only the leaf valve 202 bends.

The soft valve may be a soft valve 250 shown in FIG. Soft valve 25
0 includes two leaf valves 252 and 254, an inner peripheral side positioning member 256, an outer peripheral side positioning portion 258, and an upper chamber side seat member 260. The two leaf valves 252 and 254 have substantially the same outer diameter and different inner diameters, and the entire leaf valve 252 and a part of the leaf valve 254 overlap. The leaf valve 254 is positioned by the inner peripheral positioning member 256, and the leaf valve 252 is positioned by the outer peripheral positioning portion 2.
Positioned by 58. Outer side positioning part 258
Is provided on the outer peripheral portion of the piston 28,
A plurality of notches 262 are formed on the inner peripheral side, and are positioned by the outer peripheral surface of the leaf valve 252 abutting on the inner peripheral surface. In addition, these notches 26
2 allows the flow of the hydraulic fluid at a sufficient flow rate in the early stage of valve opening.

During the contraction of the piston rod 14, FIG.
, The leaf valve 252 is hardly bent,
While the leaf valve 254 is flexed, during extension the leaf valves 252 and 254 are flexed together. During contraction, the leaf valve 254 is flexed almost without being affected by the leaf valve 252, so that the number of leaf valves flexing during contraction and extension is different. Note that, as in the case of the above embodiment, the leaf valve 252 may have a through hole and a hydraulic pressure transmitting portion as shown in FIG. In this case, the hydraulic pressure transmitting unit 228 is disposed in a state of being located on the upper surface.

The soft valve may be a soft valve 280 shown in FIGS. The soft valve 280 includes two leaf valves 282 and 284. The leaf valve 282 has a circular outer shape, and the leaf valve 284 has a generally rectangular shape. When the fluid pressure in the intermediate fluid passage 46 is higher than the fluid pressure in the upper chamber 36 and the fluid pressure difference is small,
Only the leaf valve 282 is flexed, and when larger, both leaf valves 282 and 284 are flexed. Upper room 3
When the hydraulic pressure of the valve 6 is higher than the hydraulic pressure of the intermediate liquid passage 46, both the leaf valves 282 and 284 are bent, and a large damping force is generated.

Further, in each of the above embodiments, the valve included in the shock absorber according to one embodiment of the present invention is applied to the soft valve. It can be applied to both. Further, the structure of the shock absorber is not limited to that in the above-described embodiment. Even when the hard valve is provided in parallel with the soft valve and the liquid passage provided in series with the soft valve, one of the hard valve and the soft valve may be used. The present invention can be applied to shock absorbers having various structures such as a structure provided with only a shock absorber.
Although not specifically exemplified, the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view around a piston of a shock absorber that is one embodiment common to the present invention.

FIG. 2 is a sectional view of the entire shock absorber.

FIG. 3 is an external view of the entire shock absorber.

FIG. 4 is a sectional view of a hard valve included in the shock absorber.

FIG. 5 is a sectional view of a soft valve included in the shock absorber. This soft valve includes a leaf valve according to an embodiment of the present invention.

FIG. 6 is a plan view of a leaf valve included in the soft valve.

FIG. 7 is an operation diagram of the soft valve.

FIG. 8 is a diagram showing a damping characteristic of a damping force generated in the soft valve.

FIG. 9 is a diagram showing a damping characteristic of a damping force generated in the shock absorber.

FIG. 10 is a sectional view of a soft valve included in a shock absorber according to another embodiment of the present invention. This soft valve includes a leaf valve according to an embodiment of the present invention.

FIG. 11 is a plan view of a leaf valve included in the soft valve.

FIG. 12 is an operation diagram of the soft valve.

FIG. 13 is an operation diagram of a soft valve included in a shock absorber according to still another embodiment of the present invention.
This soft valve includes a leaf valve according to an embodiment of the present invention.

FIG. 14 is a sectional view of a soft valve included in a shock absorber according to yet another embodiment of the present invention.

FIG. 15 is an operation diagram of the soft valve.

FIG. 16 is a partial sectional view of another leaf valve included in the soft valve. This leaf valve is provided in claim 4
It is a leaf valve which is one embodiment of the invention as described in (1).

FIG. 17 is a sectional view of a soft valve included in a shock absorber according to yet another embodiment of the present invention.

FIG. 18 is an operation diagram of the soft valve.

FIG. 19 is a sectional view of a soft valve included in a shock absorber according to yet another embodiment of the present invention.

FIG. 20 is a plan view of the soft valve.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Cylinder main body 14 Piston rod 28 Piston 30 Damping force control device 40 Hard valve 42,150,180.200,250,280 Soft valve 102,104,106,152,154,156,1
82,184,186,202,204,232,25
2,254,282,284 Leaf valve 120,122,158,188,190,230 Through hole

Claims (4)

[Claims] 1. A cylinder body, a piston for partitioning the inside of the cylinder body into two chambers, and increasing and decreasing the volume of the two chambers with the operation of the shock absorber, and a piston rod fixed thereto; A valve that allows the flow of hydraulic fluid from the high-pressure chamber of the higher pressure chamber to the low-pressure chamber of the lower pressure chamber, wherein the valve includes a plurality of stacked leaf valves. ,
A shock absorber characterized in that the number of leaf valves that bend varies depending on the operation state of the shock absorber. 2. The shock absorber according to claim 1, wherein the valve allows the flow of the hydraulic fluid in both a state where the piston rod is extended and a state where the piston rod is contracted. 3. The shock absorber according to claim 2, wherein the number of leaf valves that bends in the valve varies depending on whether the piston rod is being extended or contracted. 4. A leaf valve for a shock absorber valve, wherein the leaf valve has an annular plate shape and has a through hole penetrating in a thickness direction at a portion between an outer peripheral edge and an inner peripheral edge.