JP2010164121A - Valve structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve structure satisfying ride comfort of a vehicle without sacrificing a stroke length and economy of a shock absorber. <P>SOLUTION: This means includes a valve disk 1 having a port 2 formed thereon, and a leaf valve 10 which is laminated on the valve disk 1, which has an annular shape, of which inner circumference is fixed and supported, of which outer circumference side is allowed to deform to open and close the port 2. A valve structure including an annular window 3 making an outlet end of the port 2 communicate to a leaf valve opposite end of the valve disk 1, and annular seat parts 4, 5 on which the leaf valve 10 is seated on an inner circumference and an outer circumference of the annular window 3, includes an annular groove 6 on the inner circumference side of a seat 5 on the inner circumference side of the valve disk 1. An outer diameter of the annular groove 6 is larger than at least a diameter of a position which becomes a fulcrum of deformation of the leaf valve 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a valve structure particularly suitable for a shock absorber.

  Conventionally, this type of valve structure is embodied in, for example, a piston portion of a shock absorber for a vehicle, and an annular leaf valve is stacked on an outlet end of a port provided in the piston portion. Those that open and close ports are known.

  Specifically, the piston includes an annular window communicated with the outlet end of the port at an end portion facing the leaf valve, and an annular seat portion on which the leaf valve is seated on each of the inner and outer circumferences of the annular window, The leaf valve receives pressure from the port side, and when the difference between the pressure from the front on the port side and the pressure from the back reaches the valve opening pressure, the outer edge of the spacer stacked on the back side is used as a fulcrum for bending. The port is opened by bending and separating from the outer peripheral seat (see, for example, Patent Document 1).

  In addition, the part which receives the action of the pressure from the port side of the leaf valve is a part facing the annular window before separating from the seat part on the outer peripheral side (before opening the valve), and after separating (after opening the valve) Strictly speaking, the entire outer side from the fulcrum point of deflection. However, the clearance between the leaf valve and the seat portion on the inner peripheral side, which is formed by bending the outer peripheral side of the leaf valve, is small, and it is difficult for pressure to enter the small clearance. The portion facing the seat does not contribute much to the pressure receiving area, and the effective pressure receiving area does not change so much before and after the leaf valve is opened.

  In the valve structure in which the inner periphery of the leaf valve is fixedly supported and the port is opened and closed by bending the outer periphery, the damping force is relatively large when the piston speed of the shock absorber is in the low speed region. In order to realize the damping characteristics that rise up (the characteristics of the damping force that the shock absorber generates with respect to the piston speed) and to improve the riding comfort in the vehicle, the leaf seat is not opened and the seat part on the outer peripheral side is opened. Since only the orifice provided by stamping is allowed to pass through the hydraulic oil, the bending rigidity of the leaf valve is set so as not to open when the piston speed is in the low speed region. Therefore, when the piston speed at which the leaf valve opens is in the middle to high speed region, the amount of bending of the leaf valve is insufficient, and the damping force may become too large, which may impair the riding comfort in the vehicle.

  In order to solve this problem, as shown in FIG. 4, the inner periphery of the leaf valve L is not fixedly supported and the inner periphery of the leaf valve L is fixed to the piston rod R or the piston P to the piston rod R. A shock absorber valve structure has been proposed in which the back surface of the leaf valve L is urged by a spring S through a main valve M by sliding contact with the outer periphery of a piston nut N. (See, for example, Patent Document 2).

  In the shock absorber to which this valve structure is applied, as shown in the drawing, when the piston speed when the piston P moves upward is in the low speed region, the leaf valve L does not open and strikes the seat portion on the outer peripheral side. Since the damping force is generated only by the scribed orifice, as shown in FIG. 5, when the piston speed reaches the middle-high speed region, it exhibits substantially the same damping characteristics as the valve structure in which the inner periphery is fixedly supported. The pressure of the hydraulic oil passing through the port Po acts on the leaf valve L, the leaf valve L bends and opens, and the leaf valve L, together with the main valve M, axially extends from the piston P against the urging force of the spring S. As the valve structure is lifted and moved backward, the flow path area is larger compared to a valve structure in which the inner periphery is fixedly supported, and the damping force is suppressed from being excessive, thereby improving the riding comfort in the vehicle. Rukoto can.

Japanese Patent Laying-Open No. 2003-42213 (FIG. 2) JP-A-9-291196 (FIG. 1)

  However, in the proposed valve structure as described above and the shock absorber to which the valve structure is applied, the main valve M and the spring S are essential, although it is a useful technique in terms of improving the riding comfort in the vehicle. Since the lift of the leaf valve L from the piston P needs to be permitted, the length of the entire piston portion including the valve structure becomes long, and the stroke length which is the extendable range of the shock absorber by that length In addition, it is difficult to ensure, and the increase in the number of parts and the number of processing steps increases the manufacturing cost, which is disadvantageous in terms of economy.

  The same applies when the valve structure is applied to a base valve provided between a reservoir and a pressure chamber of a shock absorber provided with a reservoir.

  Therefore, the present invention was devised to improve the above-mentioned problems, and its purpose is not only to satisfy the ride comfort in the vehicle, but also to sacrifice the stroke length and economics of the shock absorber. It is to provide a valve structure that does not occur.

  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, and a ring disk that is laminated and annularly supported with its inner periphery fixed and allowed to bend on the outer periphery side. An annular window in which the outlet end of the port communicates with an end of the valve disk facing the leaf valve, and an annular seat on which the leaf valve is seated on each of the inner and outer circumferences of the annular window In the valve structure provided with a portion, an annular groove is provided on the inner peripheral side from the seat portion on the inner peripheral side of the valve disk, and the outer diameter of the annular groove is larger than at least a diameter that serves as a fulcrum of deflection of the leaf valve. It is characterized by that.

  According to the valve structure of the present invention, the piston speed is increased while increasing the damping coefficient in the low speed region without adopting a structure in which the leaf valve is lifted from the valve disk without using the main valve or the spring. Since it is possible to reduce the slope of the damping characteristic in the high speed region, it is possible to improve the ride comfort in the vehicle, and the axial length of the piston part and the base valve part including the valve structure is not increased. It is not difficult to secure a stroke length that is a stretchable range of the shock absorber.

  Also, since only an annular groove is added to the valve disc of the conventional structure, the number of processing steps does not increase significantly, and when the valve disc is shaped by sintering, it can be manufactured without any special processing. Further, since the number of parts and the number of processing steps are not increased, economic efficiency is not sacrificed.

It is a longitudinal cross-sectional view in the piston part of the shock absorber in which the valve structure in one embodiment was embodied. It is a perspective view of the piston of the shock absorber in which the valve structure in one embodiment was embodied. It is a figure which shows the damping characteristic in the buffer which embodied the valve | bulb structure of the buffer of one Embodiment. It is a longitudinal cross-sectional view of the piston part of the buffer which actualized the valve structure of the conventional buffer. It is a figure which shows the damping characteristic in the buffer which actualized the valve structure of the conventional buffer.

  Hereinafter, a valve structure and a shock absorber according to the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a piston portion of a shock absorber in which a valve structure according to an embodiment is embodied. FIG. 2 is a perspective view of a piston of a shock absorber in which a valve structure according to an embodiment is embodied. FIG. 3 is a diagram illustrating a damping characteristic in a shock absorber in which the valve structure of the shock absorber according to the embodiment is embodied.

  As shown in FIG. 1, the valve structure of the shock absorber in one embodiment is embodied as an extension side damping valve of the piston portion of the shock absorber interposed between the vehicle body and the axle of the vehicle. Specifically, a piston 1 as a valve disk in which a port 2 is formed, and a leaf valve 10 that is laminated on the piston 1 and is annular and has an inner periphery fixedly supported and allowed to bend on the outer periphery side to open and close the port 2. And is configured.

  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 8 slidably penetrating a head member (not shown), the piston 1 provided at the end of the piston rod 8, and two pressures separated by the piston 1 in the cylinder 40 The upper chamber 41 and the lower chamber 42, which are chambers, a sealing member (not shown) for sealing the lower end of the cylinder 40, and a cylinder internal volume change corresponding to the volume of the piston rod 8 protruding and retracting from the cylinder 40 are not shown. The cylinder 40 is configured to include a reservoir or an air chamber, and the cylinder 40 is filled with a fluid, specifically, hydraulic oil.

  In the above valve structure, when the piston 1 moves upward in FIG. 1 with respect to the cylinder 40, the pressure in the upper chamber 41 rises, and the port 2 passes from the upper chamber 41 to the lower chamber 42. When the hydraulic oil moves, the leaf valve 10 provides resistance to the movement of the hydraulic oil to cause a predetermined pressure loss, thereby functioning as a damping force generating element that generates a predetermined damping force in the shock absorber.

  Hereinafter, the valve structure will be described in detail. As shown in FIGS. 1 and 2, the piston 1 that is a valve disk is formed in an annular shape, and the inside of the cylinder 40 is divided into an upper chamber 41 and a lower chamber 42. An insertion hole 1a through which the tip 8a of the piston rod 8 of the shock absorber is inserted in the shaft center, a plurality of ports 2 communicating with the upper chamber 41 and the lower chamber 42, and a lower end in FIG. 1 is formed on the outer peripheral side and the inner peripheral side of the annular window 3 connected to the lower end opening in FIG. 1 and the annular window 3 connected to each port 2. The outer peripheral side sheet part 4 and the inner peripheral side sheet part 5 that are formed, and the annular groove 6 that is formed on the inner peripheral side of the inner peripheral side sheet part 5 are configured.

  The piston 1 is provided with a pressure-side port 7 that allows a flow of hydraulic oil from the lower chamber 42 toward the upper chamber 41 when the shock absorber contracts, on the outer peripheral side of the outer peripheral seat portion 4.

  In this embodiment, the outer circumferential side seat portion 4 is provided with a stamping orifice 4a that is a recess that crosses the outer circumferential seat portion 4, and even when the leaf valve 10 is seated on the outer circumferential side seat portion 4, The port 2 is communicated with the lower chamber 42 by the stamping orifice 4a. Further, a cutout functioning as an orifice is provided on the outer periphery of the leaf valve 10 in place of the stamping orifice 4a, and even if the leaf valve 10 is seated on the outer peripheral seat portion 4, the port 2 The lower chamber 42 may be communicated with each other, and the present invention is not limited to this, and an orifice that communicates the upper chamber 41 and the lower chamber 42 may be provided separately.

  As described above, the tip 8a of the piston rod 8 is inserted into the insertion hole 1a of the piston 1, and the tip 8a of the piston rod 8 is protruded downward in FIG. The outer diameter of the tip 8a of the piston rod 8 is set to be smaller than the outer diameter on the upper side in FIG. 1 from the tip 8a, and the step 8b is formed with the outer diameter of the upper side and the tip 8a being different.

  A pressure-side leaf valve 20, a spacer 21 and a valve stopper 22 are sequentially stacked on the upper end of the piston 1 in FIG. 1, and a leaf valve 10 on the lower end in FIG. The sub leaf valve 11 and the spacer 12 are laminated in order, and these members including the piston 1 are assembled to the tip 8a of the piston rod 8, and the piston nut 9 is screwed into the screw portion 8c provided at the tip 8a of the piston rod 8. By wearing, it is clamped by the step 8b of the piston rod 8 and the piston nut 9 and fixed to the piston rod 8.

  The leaf valve 10 is an annular plate. When the leaf valve 10 is assembled to the tip 8a of the piston rod 8 as described above, the inner periphery is fixedly supported and the outer periphery is bent, and the leaf valve 10 is set to be so-called outward opening. .

  And since the inner periphery of this leaf valve 10 is supported by the spacer 12 whose outer diameter is set smaller than the leaf valve 10 and the sub leaf valve 11 stacked on the lower side in FIG. The leaf valve 10 bends with a circumference having substantially the same diameter as the outer edge of the spacer 12 as a fulcrum.

  The outer diameter of the annular groove 6 formed in the piston 1 is set to be larger than the outer diameter of the spacer 12, and the fulcrum of the leaf valve 10 is inward of the outer diameter of the annular groove 6. It is supposed to be arranged in.

  Similar to the leaf valve 10, the pressure side leaf valve 20 has an inner periphery fixed to the piston rod 8 and set to open outward so as to open and close the pressure side port 7. When the shock absorber contracts, It functions as a damping force generating element that gives resistance to the flow of hydraulic oil from 42 to the upper chamber 41 and generates a predetermined damping force on the shock absorber. The pressure-side leaf valve 20 includes a through hole 20a so as not to block the entrance of the port 2.

  The sub leaf valve 11 is composed of an arbitrary number of annular plates, and is laminated on the rear surface of the leaf valve 10 to increase the apparent bending rigidity of the leaf valve 10 and to increase the number of annular plates. The bending rigidity can be adjusted according to the setting, and the damping characteristic of the shock absorber to which the valve structure is applied can be finely adjusted according to the setting of the outer diameter. If the damping characteristic required for the shock absorber can be realized by the bending rigidity of only the leaf valve 10, the sub leaf valve 11 is unnecessary and can be omitted.

  Note that the end on the inner peripheral side of the annular groove 6 of the piston 1 is lower than the outer peripheral seat 4 and the inner peripheral seat 5, whereby the leaf valve 10 is connected to the outer peripheral seat 4 and the inner peripheral. The outer peripheral side of the leaf valve 10 is bent in the state of being seated on the side seat portion 5, so that the leaf valve 10 is initially bent.

  By setting the deflection amount of the initial deflection, it is possible to adjust the valve opening pressure when the leaf valve 10 is separated from the outer peripheral side seat portion 4 and opens the port 2. The deflection amount of the initial deflection is It can be set by the difference in height between the end portion on the inner peripheral side from the annular groove 6 and the height of the outer peripheral side seat portion 4 and the inner peripheral side seat portion 5. In addition, by setting the height of the outer peripheral side seat part 4 higher than the height of the inner peripheral side seat part 5, the port 2 can be reliably closed when seated.

  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 upper chamber 41 increases, and the upper chamber 41 is increased. The hydraulic fluid inside passes through the port 2 and tries to move into the lower chamber 42.

  When the piston speed when the shock absorber extends is in the low speed region, the differential pressure between the upper chamber 41 and the lower chamber 42 does not reach the valve opening pressure of the leaf valve 10, and the hydraulic oil passes through the punch orifice 4a. The upper chamber 41 moves from the upper chamber 41 to the lower chamber 42, and resistance is given to the flow of hydraulic oil at the stamping orifice 4a. The damping characteristic of the shock absorber at this time is as shown by the solid line in FIG. 3, and the damping coefficient is relatively large in this low speed region.

  On the other hand, the speed of the piston 1 reaches the middle-high speed region, and the difference between the pressure in the upper chamber 41 and the pressure in the lower chamber 42 increases, and the leaf valve 10 is bent and is separated from the outer seat portion 4. The leaf valve 10 is also separated from the inner peripheral side seat portion 5 due to the deflection on the outer peripheral side, and since the fulcrum of the leaf valve 10 is inside the outer diameter of the annular groove 6, the annular groove 6 communicates with the port 2. Is done. Here, the annular groove 6 forms a gap between the leaf valve 10 and the pressure valve so that the pressure can be sufficiently transmitted. 2, the pressure in the upper chamber 41 acts also in the annular groove 6.

  Then, in the valve structure of this embodiment, the pressure receiving surface of the leaf valve 10 before the valve opening is a portion facing the annular window 3, but after the valve opening, the pressure receiving surface of the leaf valve 10 is also in the annular groove 6. Since the pressure in the chamber 41 acts, the larger one of the inner diameter of the annular groove 6 or the outer diameter of the spacer 12 can be the inner limit, and the entire outer periphery can be the pressure receiving surface from the limit. Then, the pressure receiving area of the leaf valve 10 increases.

  Therefore, after opening the valve, the force that causes the leaf valve 10 to bend due to the pressure of the upper chamber 41 acting through the port 2 is increased after opening the valve, so that the annular groove is formed on the inner peripheral side from the inner peripheral side seat portion. Compared to a valve structure that does not include the valve structure, the amount of bending of the leaf valve 10 is increased even when the same pressure is applied after the valve is opened, and the annular gap between the leaf valve 10 and the outer seat portion 4 is increased. Therefore, the generated damping force with respect to the piston speed of the shock absorber becomes small.

  In other words, the damping characteristics when the piston speed is in the medium-high speed region are as shown by the solid line in FIG. 3, and although proportional to the increase in piston speed, the damping coefficient is smaller than the low-speed region, and is indicated by the broken line. Even when compared with the damping characteristic of a conventional valve structure having a leaf valve whose inner periphery is fixedly supported, the slope of the damping characteristic is reduced.

  As is clear from the above description, in the valve structure of the present embodiment, when the piston speed is in the middle and high speed region without using the main valve or the spring to lift the leaf valve from the piston as the valve disk. It is possible to reduce the slope of the attenuation characteristic.

  Therefore, in the valve structure of the present embodiment, while the damping coefficient is increased in the low speed region of the piston speed, the slope of the damping characteristic in the medium speed range is compared with the conventional shock absorber valve structure. Since it is possible to reduce the size, it is possible to improve the ride comfort in the vehicle, and it is not necessary to use a structure that lifts the leaf valve from the valve disk without using the main valve or spring, so the valve structure is included. The axial length of the piston portion does not become long, and it is not difficult to secure a stroke length that is an extendable range of the shock absorber.

  Also, since only an annular groove is added to the valve disc of the conventional structure, the number of processing steps does not increase significantly, and when the valve disc is shaped by sintering, it can be manufactured without any special processing. Further, since the number of parts and the number of processing steps are not increased, economic efficiency is not sacrificed.

  Furthermore, when it is desired to reduce the damping characteristic in the medium / high speed region as low as possible, the pressure receiving area of the leaf valve 10 after the valve opening may be maximized, so that the inner diameter of the annular groove 6 is set to bend the leaf valve 10. What is necessary is just to set below the outer diameter of the spacer 12 which determines the fulcrum position. In other words, the inner edge of the annular groove 6 only needs to be disposed inside the annular projection line projected onto the leaf valve-facing end of the piston 1 that is the valve disk and the outer edge of the spacer 12. The comfort is further improved.

  When the leaf valve 10 is opened and then closed, the annular groove 6 through which the pressure in the upper chamber 41 is propagated is also closed, so that the pressure in the annular groove 6 is increased and the valve opening pressure of the leaf valve 10 is changed. However, the annular groove 6 communicates with the lower chamber 42, and a passage having flow resistance such as a throttle or choke is provided, and the annular groove 6 after valve closing is depressurized. The change in the valve opening pressure can be eliminated. This passage only needs to communicate with the annular groove 6 and the lower chamber 42, and can be provided at an arbitrary position. Specifically, the piston 1, the piston rod 5, the leaf valve 10, the sub-leaf valve 11, etc. What is necessary is just to provide in a member.

  Further, in the present embodiment, in order to explain the change of the damping characteristic, the piston speed is provided with sections of low speed, medium speed, and high speed, but the speeds at the boundaries of these sections are set arbitrarily. be able to.

  This is the end of the description of the embodiment of the valve structure. However, the valve structure of the present invention may be embodied in the compression side damping valve of the piston portion of the shock absorber. If it is provided, it can be embodied in a base valve section that partitions the reservoir and the pressure chamber. In that case, the reservoir and the pressure chamber may be partitioned by a valve disk. There is no loss of the operational effect that the ride comfort in the vehicle can be improved without sacrificing the stroke length and economy of the vessel. Also, the scope of the invention is not limited to the details shown or described.

The valve structure of the present invention can be used for a shock absorber valve.

DESCRIPTION OF SYMBOLS 1 Piston 1a which is a valve disc Insertion hole 2 Port 3 Annular window 4 Outer peripheral side seat part 4a Stamping orifice 5 Inner peripheral side seat part 6 Annular groove 7 Pressure side port 8 Piston rod 8a Piston rod tip 8b Step part 8c Screw part 9 Piston Nut 10 Leaf valve 11 Sub leaf valve 12, 21 Spacer 20 Pressure side leaf valve 20a Through hole 22 Valve stopper 40 Cylinder 41 Upper chamber 42 Lower chamber

Claims (1)

A valve disc having a port formed therein, and a leaf valve that is laminated on the valve disc and is annular and has an inner periphery fixedly supported and allowed to bend on the outer periphery side to open and close the port. In a valve structure in which an annular window having an end communicating with an outlet end of a port and an annular seat portion in which a leaf valve is seated on each of an inner periphery and an outer periphery of the annular window is provided. A valve structure characterized in that an annular groove is provided on the inner peripheral side from the portion, and the outer diameter of the annular groove is at least larger than the diameter serving as a fulcrum for bending the leaf valve.

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