JP2011058562A - Valve structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide valve structure surely lessening sudden change in damping characteristics. <P>SOLUTION: The valve structure includes: a valve disk 1 to which a port 2 is formed; a shaft member 5 stand on the valve disc 1; an annular main leaf valve stacked on the valve disk and installed to the shaft member to open/close to the port; and a plurality of sub leaf valves stacked on the main leaf valve and bent together with the main leaf valve. In the valve structure, a sub leaf valve abutting on the main leaf valve has an inner periphery eccentric from an outer periphery and is an eccentric leaf valve set to have an outer diameter within an outer edge of the main leaf valve when seen in the axial direction, and an outer shape of the sub leaf valve stacked to be closer to a side opposed to the valve disk from the eccentric leaf valve is within the outer edge of the eccentric leaf valve when seen in the axial direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an improved valve structure.

  Conventionally, in this type of valve structure, for example, a piston that is embodied in a piston portion of a hydraulic shock absorber for a vehicle, for example, a piston that separates two pressure chambers in the shock absorber, and a port provided in the piston And an annular laminated leaf valve seated on an annular valve seat disposed on the outer periphery of the cylinder, and a valve that opens and closes the port with this laminated leaf valve is known.

  The valve structure that opens and closes the port by bending the outer peripheral side of the laminated leaf valve includes an orifice formed by a notch provided in the annular valve seat or a notch provided in the outer periphery of the leaf valve in contact with the annular valve seat. The hydraulic oil is allowed to pass through the orifice until the laminated leaf valve reaches a valve opening pressure at which it is separated from the annular valve seat.

  By configuring the valve structure as described above, when the piston speed is low, it is possible to obtain a damping characteristic (a change in the damping force with respect to the piston speed) that is a square characteristic peculiar to the orifice where the damping force rises. When the piston speed goes out of the low speed range and becomes medium to high speed, the laminated leaf valve is separated from the annular valve seat, so that the damping characteristic can be reduced so that the inclination of the damping characteristic becomes smaller than when the piston speed is in the low speed range. Thus, a damping force suitable for the riding comfort of the vehicle can be exhibited.

  However, in the above valve structure, the damping characteristic changes abruptly at the boundary between the low speed region and the medium high speed region of the piston speed, so that the vibration state of the vehicle body changes, and this is perceived by the vehicle occupant. It may be a factor that impairs the ride comfort.

  Therefore, the outer shape (outer shape) of the spacer, which is laminated on the anti-piston side, which is the back side of the laminated leaf valve and regulates the deflection of the laminated leaf valve, is not a circle but a triangle, or the inner circumference is decentered with respect to the outer circumference. In addition, the entire circumference of the laminated leaf valve is not bent at the same time to open the port, but the outer circumference of the laminated leaf valve is partially bent in order to reduce sudden changes in damping characteristics. Has been proposed (see, for example, Patent Document 1).

JP 11-336825 A

  However, the damping force valve configured as described above may be pointed out to have the following problems, although there is no particular problem.

  This is good if the number of stacked leaf valves in the stacked leaf valve is small, but if the number of stacked layers is large, the outer periphery of the stacked leaf valve is partially bent in order only by devising the shape of the spacer. The effect is small, and there is a possibility that a sudden change in the attenuation characteristic cannot be sufficiently mitigated.

  Accordingly, the present invention has been developed to improve the above-described problems, and the object of the present invention is to provide a valve structure that can reliably mitigate sudden changes in damping characteristics. is there.

  In order to solve the above-described object, the problem-solving means in the present invention includes a valve disk in which a port is formed, a shaft member rising from the valve disk, and a layer stacked on the valve disk and mounted on the shaft member to open and close the port. And a plurality of sub leaf valves that are stacked on the main leaf valve and can be bent together with the main leaf valve. The eccentric leaf valve has an eccentric inner periphery and is set to an outer diameter that fits within the outer edge of the main leaf valve when viewed from the axial direction. The outer shape is designed to fit within the outer edge of the eccentric leaf valve as viewed from the axial direction. And features.

  According to the valve structure of the present invention, the sub leaf valve stacked on the side opposite to the valve disc of the main leaf valve is an eccentric leaf valve whose inner periphery is eccentric with respect to the outer periphery, and the main leaf valve is formed by the sub leaf valve. Since the unsupported outer peripheral portion is gradually bent and the port is gradually opened, a sudden change in the attenuation coefficient can be mitigated.

  In addition, the sub leaf valve, which is a fulcrum of deflection of the outer periphery of the main leaf valve, is directly stacked on the side opposite to the valve disc of the main leaf valve, and is further stacked on the side opposite to the piston of the sub leaf valve as an eccentric leaf valve. Since the sub-leaf valve has an outer shape that fits within the outer edge of the sub-leaf valve when viewed from the axial direction, the sub-leaf valve does not hinder only the outer periphery of the main leaf valve, and the sub-leaf valves are stacked. Even if the number is large, the outer periphery of the main leaf valve can be gradually bent, and a sudden change in the damping characteristic can be reliably mitigated.

It is a longitudinal cross-sectional view of the piston part of the shock absorber in which the valve structure in one embodiment was embodied. It is a top view in the state where the main leaf valve and sub-leaf valve of one embodiment were laminated. It is the figure which showed the damping characteristic of the expansion | extension side of the buffer with which the valve structure in one Embodiment was embodied.

  The valve structure of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the valve structure in one embodiment is embodied as an extension side damping valve of a piston portion of a shock absorber, and rises from a piston 1 that is a valve disk in which a port 2 is formed, and the piston 1. An end 5a of the piston rod 5 as a shaft member, an annular main leaf valve 10 which is annular and is mounted on the outer periphery of the end 5a and which is stacked on the piston 1 to open and close the port 2, and a main leaf valve 10 And a plurality of sub leaf valves 11 and 12 that can be bent together with the main leaf valve 10.

  On the other hand, a shock absorber in which the valve structure is embodied is well known and will not be described in detail, but specifically, for example, a cylinder 40 and a head member (not shown) that seals the upper end of the cylinder 40. ), A piston rod 5 that slidably passes through a head member (not shown), a piston 1 that is inserted into the tip 5a of the piston rod 5 that forms a shaft member, and is fixed to the tip 5a, and a cylinder 40 An upper chamber 41 in FIG. 1, a lower chamber 42 in the lower side in FIG. 1, a sealing member (not shown) that seals the lower end of the cylinder 40, and the cylinder 40 protrude from the cylinder 40. A cylinder or an air chamber (not shown) that compensates for a change in the cylinder volume corresponding to the volume of the piston rod 5 is provided, and the cylinder 40 is filled with a fluid, specifically, hydraulic oil.

  In this case, in this case, when the piston 1 moves upward in FIG. 1 with respect to the cylinder 40, the pressure in the one chamber 41 rises and the port from the one chamber 41 to the other chamber 42 is ported. 2, when the hydraulic oil moves, the main leaf valve 10 and the sub leaf valves 11, 12 cooperate with the movement of the hydraulic oil to give resistance and cause a predetermined pressure loss. It functions as a damping force generating element that generates a predetermined damping force.

  Hereinafter, the valve structure will be described in detail. The piston 1 serving as a valve disk is formed in a bottomed cylindrical shape, and an insertion hole 1b through which the tip 5a of the piston rod 5 of the shock absorber is inserted into the axial center of the bottom 1a; A port 2, a window 3 communicating with the port 2, an annular valve seat 1c formed on the outer peripheral side of the window 3 serving as an outlet end of the port 2 and projecting from the bottom 1a of the piston 1 toward the main leaf valve 10; A cylindrical portion 1e extending to the side is provided.

  The piston 1 is provided with a pressure-side port 1d that allows a flow of hydraulic oil from the other chamber 42 to the one chamber 41 when the shock absorber contracts, on the outer peripheral side of the port 2 on the extended side of the bottom 1a. It has been.

  The piston rod 5 is inserted into the insertion hole 1b of the piston 1 as described above, and the tip of the piston rod 5 is protruded downward in FIG. The outer diameter of the tip 5a of the piston rod 5 is set to be smaller than the outer diameter on the upper side in FIG. 1 from the tip 5a, and a step portion 5b is formed at a portion where the outer diameters of the upper side and the tip are different. Yes.

  Then, after inserting the tip 5a of the piston rod 5 into the inner circumference of the check valve 20, the spacer 21 and the valve stopper 22 on the pressure side, and the insertion hole 1b of the piston 1, respectively, the piston 1 is inserted into the tip 5a. After assembling the annular leaf valve 10, the sub leaf valves 11, 12, and the spacer 13 arranged at the lower side in FIG. 1, the piston nut 6 is screwed onto the screw portion 5 c provided at the tip 5 a of the piston rod 5. Thus, the piston 1 and each member are sandwiched between the step 5 b of the piston rod 5 and the piston nut 6 and fixed to the piston rod 5.

  In the case of this embodiment, the suction side end which is the lower end of the port 1d is not blocked by the main leaf valve 10 which is arranged on the outer peripheral side from the opening end of the port 2 and is stacked on the piston 1. The suction side end that is the upper end of the port 2 is not blocked by the check valve 20. If the port 2 is not closed by the check valve 20 and the port 1d is not closed by the main leaf valve 10, the arrangement and shape of the port 2 are not limited to those shown in the figure. You may employ | adopt the structure which arrange | positions on the periphery and makes a valve seat what is called a petal type.

  Also, as described above, the main leaf valve 10, while ensuring the sliding contact length in the axial direction necessary for avoiding the shaft shake with respect to the cylinder 40, by making the piston 1 into a bottomed cylindrical shape. Part or all of the members constituting the valve structure such as the sub-leaf valves 11 and 12 can be accommodated in the piston 1, and the piston 1 from the upper end in FIG. 1 to the lower end in FIG. There is an advantage that the length of can be shortened and the piston portion can be downsized.

  A main leaf valve 10 and sub-leaf valves 11 and 12 are stacked on the bottom 1a of the piston 1. The main leaf valve 10 and the sub-leaf valves 11 and 12 are annular and are arranged at the tip 5a of the piston rod 5. It is mounted on the outer periphery, the inner peripheral side is clamped and fixed by the piston 1 and the piston nut 6, and the outer periphery is a free end to allow the outer periphery to bend.

  The main leaf valve 10 is on a ring, and the upper surface in FIG. 1 can be brought into contact with the valve seat 1c to close the port 2 of the piston 1, and the port 2 is opened by bending. It has become. Further, the sub leaf valves 11 and 12 can be bent together with the main leaf valve 10, and serve as an adjustment element for the bending rigidity of the entire valve including the main leaf valve 10.

  Of the sub-leaf valves 11 and 12, the sub-leaf valve 11 in contact with the side opposite to the piston of the main leaf valve 10 is annular and has an inner periphery that is eccentric with respect to the outer periphery, as shown in FIG. Furthermore, an eccentric leaf valve set to an outer diameter that fits within the outer edge of the main leaf valve 10 when viewed from the axial direction.

  Further, the outer peripheral shape of the sub-leaf valve 12 stacked on the anti-piston side, which is on the side opposite to the valve disc from the sub-leaf valve 11 as the eccentric leaf valve, that is, the outer shape is the outer edge of the sub-leaf valve 11 when viewed from the axial direction. The shape fits inside.

  Specifically, as shown in FIG. 2, the sub-leaf valve 12 has an annular shape in which the inner and outer circumferences are set concentrically. In this case, the outer edge is the outer edge of the sub-leaf valve 11 when viewed from the axial direction. It is set to the outer diameter that touches. The definition that the outer shape of the sub-leaf valve 12 fits within the outer edge of the sub-leaf valve 11 as an eccentric leaf valve when viewed from the axial direction is that the outer shape of the sub-leaf valve 12 and the outer edge of the sub-leaf valve 11 are as described above. It includes touching when viewed from the axial direction.

  Note that the outer shape of the sub-leaf valve 12 may not necessarily be an annular shape as long as it is within the outer edge of the sub-leaf valve 11 as an eccentric leaf valve when viewed from the axial direction.

  In this embodiment, the sub-leaf valve 12 is composed of a single annular plate. However, the sub-leaf valve 12 may be composed of a plurality of annular plates. Any sub-leaf valve 11 that is laminated on the sub-leaf valve 11 that is an eccentric leaf valve when it is composed of a plurality of valves may be arbitrary depending on the damping characteristic (relationship of the damping force to the piston speed) realized by the structure. As long as the outer shape of the sub-leaf valve 11 is within the outer edge of the sub-leaf valve 11 when viewed from the axial direction.

  The valve seat 1c on which the main leaf valve 10 is seated is provided with a recess 1f. When the main leaf valve 10 is seated on the valve seat 1c and the port 2 is closed, the recess 1f The chamber 41 communicates with the other chamber 42, and the concave portion 1f functions as a fixed orifice.

  Instead of providing the recess 1f that functions as a fixed orifice as described above, a notch that functions as a fixed orifice may be provided from the outer edge of the main leaf valve 10 toward the inner periphery. When the cutout is provided in this way, the main leaf valve 10 is constituted by two annular plates so that the sectional area of the orifice is set by the plate thickness and the cutout width of the annular plate while seated on the valve seat 1c. May be.

  Next, the operation of the valve structure in the embodiment will be described. As described above, when the piston 1 moves upward in FIG. 1 with respect to the cylinder 40, the pressure in the one chamber 41 increases, and the one chamber 41 increases. The hydraulic fluid inside passes through the port 2 and tries to move into the other chamber 42.

  When the piston speed, which is the expansion / contraction speed of the shock absorber, is in the very low speed region, the main leaf valve 10 is configured so that the difference between the pressure in the one chamber 41 and the pressure in the other chamber 42 is small. While remaining closed, the hydraulic oil passes through a fixed orifice formed by the recess 1f provided in the valve seat 1c described above.

  Therefore, the damping characteristic (relationship of the damping force to the piston speed) at this time is as shown by the solid line in FIG. 3, and the damping coefficient is relatively large in this very low speed region.

  On the other hand, when the speed of the piston 1 reaches the low speed region, the difference between the pressure in the one chamber 41 and the pressure in the other chamber 42 increases, and the force that pushes down the main leaf valve 10 of hydraulic oil downward in FIG. 1 increases. The outer periphery of the main leaf valve 10 is bent.

  Here, a sub leaf valve 11 as an eccentric leaf valve whose inner periphery is eccentric with respect to the outer periphery is laminated on the back surface of the main leaf valve 10, and the main leaf valve 10 is an outer periphery that is not supported by the sub leaf valve 11. Start bending from the part. At the beginning of the bending, the outer peripheral portion that is not supported by the sub-leaf valve 11 is bent with the outer edge of the sub-leaf valve 11 as a fulcrum, so that the apparent bending rigidity in the outer peripheral portion is the same as the outer edge of the main leaf valve 10 and the sub-leaf. The portion a having the largest radial difference between the outer edges of the bulb 11 is the smallest, and the portion b having the smallest radial difference is the largest.

  Therefore, the outer peripheral portion of the main leaf valve 10 that is not supported by the sub leaf valve 11 begins to bend from the portion a with respect to the increase in piston speed, and gradually bends toward the portion b as shown by the arrow in FIG. Finally, the portion b is bent and the port 2 is opened over the entire circumference of the valve seat 1c.

  Since the main leaf valve 10 bends in this way, when the piston speed is in the low speed region, the gap between the valve seat 1c and the leaf valve 10 gradually increases as the piston speed increases, and the port 2 As shown by the solid line in FIG. 3, the damping characteristic when the piston speed is in the low speed region is smaller than the damping coefficient obtained by the fixed orifice when the piston speed is in the very low speed region. In addition, the damping coefficient gradually and smoothly decreases as the piston speed increases.

  On the other hand, when the speed of the piston 1 reaches the middle-high speed region and the difference between the pressure in the one chamber 41 and the pressure in the other chamber 42 increases, the force that pushes down the main leaf valve 10 of the hydraulic oil downward in FIG. As the main leaf valve 10 and the sub leaf valves 11 and 12 are bent, the port 2 is greatly opened.

  As described above, when the main leaf valve 10 and the sub leaf valves 11 and 12 are bent, a large gap is generated between the valve seat 1c and the main leaf valve 10, and the port 2 is greatly opened. Increases in proportion to That is, as shown by the solid line in FIG. 3, the damping characteristic when the piston speed is in the medium / high speed region is smaller than the damping coefficient depending on the fixed orifice in the very low speed region, although proportional to the increase in the piston speed. The slope of the attenuation characteristic becomes small.

  The attenuation coefficient when the piston speed is in the low speed region gradually and smoothly changes from a high attenuation coefficient in the very low speed region to a small attenuation coefficient in the medium to high speed region, so that sudden changes in the attenuation coefficient can be mitigated. it can.

  A sub leaf valve 11 serving as a fulcrum for bending the outer periphery of the main leaf valve 10 is directly laminated on the anti-piston side, which is the anti-valve disk side of the main leaf valve 10, and is further sub-leaf valve as an eccentric leaf valve. 11, the outer shape of the sub-leaf valve 12 stacked on the side opposite to the piston is configured to fit within the outer edge of the sub-leaf valve 11 when viewed from the axial direction. Even if the number of stacked sub-leaf valves 12 is not hindered, the outer periphery of the main leaf valve 10 can be gradually bent, and a sudden change in the damping characteristic can be reliably mitigated. .

  In addition, when the sub-leaf valve 12 is formed in an annular shape having an inner circumference and an outer circumference that are concentric, it is not necessary to position the sub-leaf valve 11 in the circumferential direction, so that the assembly is easy and the damping characteristic is also a product. It is possible to enjoy the advantage of not varying every time.

  In this embodiment, in order to explain the change of the damping characteristic, the piston speed is provided with the sections of the low speed, the low speed, and the medium speed, but the speed at the boundary between these sections is set arbitrarily. can do.

  This is the end of the description of the embodiment of the valve structure, but the valve structure of the present invention can be embodied in the compression side damping valve of the piston portion of the shock absorber, or in the base valve portion. Thus, the effects of the present invention are not lost.

  In the above-described embodiment, the shaft member is the tip 5a of the piston rod 5, but instead of this, a shaft member that is integral with or separate from the valve disk may be provided on the valve disk.

  It should be noted that the scope of the present invention is not limited to the details shown or described.

The present invention is applicable to a valve such as a shock absorber.

DESCRIPTION OF SYMBOLS 1 Piston 1a which is a valve disc Bottom part 1b Insertion hole 1c Valve seat 1d, 2 Port 1e Tube part 1f Recess 3 Window 5 Piston rod 5a Piston rod tip 5b Step part 5c Screw part 6 Piston nut 10 Main leaf valve 11 Sub-leaf valve material 12 as an eccentric leaf valve Sub-leaf valve 13 Spacer 20 Check valve 21 Spacer 22 Valve stopper 40 Cylinder 41 One chamber 42 Other chamber

Claims (2)

A valve disk in which a port is formed, a shaft member rising from the valve disk, an annular main leaf valve that is stacked on the valve disk and mounted on the shaft member to open and close the port, and a main leaf that is stacked on the main leaf valve In a valve structure including a plurality of sub-leaf valves that can be bent together with the valve, the sub-reel valve that contacts the main leaf valve has an inner periphery that is eccentric with respect to the outer periphery and the main leaf valve as viewed from the axial direction. It is an eccentric leaf valve set to an outer diameter that fits within the outer edge, and the outer shape of the sub-leaf valve stacked on the side opposite to the valve disc from the eccentric leaf valve is shaped to fit within the outer edge of the eccentric leaf valve as viewed from the axial direction. A valve structure characterized by being made. The valve structure according to claim 1, wherein the sub-leaf valve laminated on the side opposite to the valve disc from the eccentric leaf valve has a concentric inner and outer periphery.

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