JP5324239B2 - Valve structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve structure which can facilitate the securement of the stroke length in a shock absorber and improve riding comfort in a vehicle without sacrificing cost efficiency. <P>SOLUTION: The valve structure is provided with a valve disk 1 in which a port 2 is formed, a leaf valve 10 which is laminated on the valve disk 1 and formed in an annular shape, and which opens/closes the port 2 by fixing and supporting an inner periphery and allowing the deformation to an outer peripheral side, and a biasing member 15 which suppresses the deformation of the leaf valve 10 by biasing the leaf valve 10 in a direction of blocking the port 2, wherein the leaf valve 10 is formed by laminating a plurality of annular plates 10a and an annular initial ring 11 having the inside diameter set to be larger in diameter than the inside diameter of the annular plate 10a is interposed between optional annular grooves 10a. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an improved valve structure.

  In recent years, particularly in a shock absorber interposed between the body of an automobile and an axle, when the piston speed is in a low speed region, characteristics of the damping force generated with respect to the piston speed (damping characteristics) The damping force is increased by increasing the slope of the cylinder, and the slope of the damping force characteristic (damping characteristic) generated with respect to the piston speed when the piston speed is in the medium to high speed range is reduced, so that the piston speed is medium to high. It has been considered that making the damping force as low as possible in the region greatly contributes to improving the ride comfort of the vehicle.

  In addition, the damping force of the shock absorber is generated by generating a differential pressure in the two working chambers in the shock absorber by a damping valve embodied in the piston portion or the like of the shock absorber. For example, there is known a structure in which an annular leaf valve whose inner periphery is fixedly supported is laminated on an outlet end of a port provided in a piston portion, and the port is opened and closed by this leaf valve.

  And, in this valve structure that opens and closes the port with a leaf valve by fixing and supporting the inner periphery of the leaf valve and bending the outer periphery side, the damping force in the medium and high speed range becomes too large, and the ride comfort in the vehicle is increased. It is difficult to satisfy the above-mentioned recent requirements. Therefore, in order to cope with this, as shown in FIG. 3, although the inner periphery of the leaf valve L is fixedly supported, the bending rigidity of the leaf valve L is set low, and the valve opening pressure due to the reduction of the bending rigidity is reduced. There is a valve structure provided with a coil spring S that urges the leaf valve L in a direction to close the port Po by pressing the leaf valve L from the back side in order to prevent the decrease (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2004-190716 (FIG. 1) JP-A-9-291196 (FIG. 1)

  However, in the valve structure disclosed in Japanese Patent Application Laid-Open No. 2004-190716, the rise of the damping force is slow in the low speed region of the piston speed, and the slope of the damping coefficient in the medium and high speed region is still high. However, the above requirement cannot be satisfied. In order to eliminate this, it is only necessary to increase the amount of deflection of the leaf valve L when the piston speed is in the middle to high speed region. For this purpose, the spring constant of the coil spring S must be set low, but if this is done, the initial load by which the coil spring S urges the leaf valve L is reduced and the valve opening pressure is reduced. It is necessary to lengthen the natural length of the coil spring S while maintaining the compression length as it is, which increases the overall length of the valve structure, which is disadvantageous in terms of securing the stroke of the shock absorber, and is costly and sacrifices cost. become.

In addition, 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 slid onto the outer periphery of the guide cylinder G attached to the outer periphery of the piston rod R ′. A valve structure in which the back surface of the leaf valve L ′ is urged through a main valve M by a coil spring S ′ is disclosed in Japanese Patent Laid-Open No. 9-291196.
In this valve structure, when the piston speed when the piston P moves upward is in the low speed region, the outer peripheral side of the leaf valve L ′ bends with the contact portion of the main valve M stacked on the leaf valve L ′ as a fulcrum. Demonstrates substantially the same damping characteristics as the valve structure in which the inner periphery is fixedly supported. When the piston speed reaches the middle-high speed region, the pressure of the hydraulic oil passing through the port Po ′ acts on the leaf valve L ′, The leaf valve L ′ lifts and retracts in the axial direction from the piston P together with the main valve M against the biasing force of the coil spring S ′, so that it is compared with the valve structure of the shock absorber in which the inner periphery is fixedly supported. As a result, the passage area is increased and the damping force is suppressed from being excessive, so that the riding comfort in the vehicle can be improved, and a damping characteristic that satisfies the above requirements can be realized.

  However, in the valve structure shown in FIG. 4, many spacers are stacked between the main valve M and the leaf valve L ′, which increases the cost and the number of parts. Since the leaf valve L ′ and the spacer are mounted on the outer periphery of the guide cylinder G, it may be inserted between the guide cylinder G and the piston P at the time of assembly processing. Is lacking.

  Therefore, the present invention has been developed to improve the above-described problems, and the object of the present invention is to ensure the stroke length in the shock absorber without sacrificing the economy and to improve the riding comfort in the vehicle. It is to provide a valve structure that can be improved.

Inner To solve the above object, problem solving means in the present invention comprises a valve disc which ports are formed with the piston rod axis portion is inserted, an annular while being laminated on the valve disc a leaf valve that circumference to open and close the allowed deflection of the fixed support is the outer circumferential side the port, a piston nut fixing the valve disc and the leaf valve in the piston rod, the leaf valve in a direction for closing the port in the valve structure and a coil spring and by energizing suppressing the deflection of the leaf valve, the leaf valve is configured by stacking a plurality of annular plates mounted directly on the outer periphery of the piston rod, the Lee and interposed initials ring annular inner diameter to any annular plates are set to have a larger diameter than the inner diameter of the annular plate It provides an initial deflection to the annular plate which is laminated on the back side of the tangential ring, and characterized in that setting the valve opening pressure of the leaf valve in the biasing force of the biasing force and the coil spring due to the initial deflection of the annular plate To do.

Even if the spring constant of the coil spring is set low, the valve opening pressure of the leaf valve can be adjusted by the initial ring, and most of the valve opening pressure is applied by the urging force due to the initial deflection of the annular plate. Can be avoided. Therefore, according to the valve structure of the present invention, the valve opening pressure of the leaf valve can be adjusted by providing the initial valve, the damping force can be raised when the piston speed is in the low speed region, The slope of the attenuation coefficient in the region can be reduced.

  Therefore, according to this valve structure, the damping characteristics of the shock absorber can be made suitable for vehicle suspension applications, and the riding comfort in the vehicle can be improved.

  In addition, since the above effect can be obtained simply by applying the initial valve to a damping valve in which the conventional valve structure is embodied, the manufacturing cost is not significantly increased, and the economy may be sacrificed. Absent.

  Furthermore, since it is not necessary to secure the valve opening pressure of the leaf valve by using a long natural coil spring compressed at a large compression ratio, the overall length of the valve structure is not lengthened, and the shock absorber There is no problem that the stroke length, which is the extendable range, is shortened, and the mounting property on the vehicle is not deteriorated.

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 figure which shows the damping characteristic in the buffer which embodied the valve | bulb structure in 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 longitudinal cross-sectional view of the piston part of 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 diagram illustrating a damping characteristic in the shock absorber in which the valve structure 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, and is connected to the tip of the piston rod 5 and is placed in the shock absorber. A piston 1 as a valve disk having a port 2 that separates the chamber 41 and the lower chamber 42 and communicates the upper chamber 41 and the lower chamber 42, and is laminated on an end surface of the piston 1 on the lower chamber 42 side. An annular leaf valve 10 that is fixedly supported at the periphery and is allowed to bend on the outer peripheral side to close the downstream of the port 2, and a leaf valve 10 that biases the leaf valve 10 in a direction to close the port 2 to prevent the leaf valve from being bent. A coil spring 15 as a biasing member and an annular initial ring 11 interposed between arbitrary annular plates 10a among a plurality of annular plates 10a constituting the leaf valve 10 are 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 5 slidably penetrating a head member (not shown), the piston 1 provided at the end of the piston rod 5, and two upper portions separated by the piston 1 in the cylinder 40 The chamber 41, the lower chamber 42, a sealing member (not shown) that seals the lower end of the cylinder 40, and a reservoir or air (not shown) that compensates for the volume change in the cylinder corresponding to the volume of the piston rod 5 protruding and retracting from the cylinder 40 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. The piston 1 serving as a valve disk is formed in a bottomed cylindrical shape, and is provided at an axial center portion of the bottom portion 1a, through which a piston rod 5 of a shock absorber is inserted, and a port. 2, a window 3 communicating with the port 2, an annular valve seat 1 c formed on the outer peripheral side of the window 3 serving as an outlet end of the port 2, and a cylindrical portion 1 e extending to the outer peripheral side. ing.

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

  Further, 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 projected 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, a pressure side leaf valve 100, a spacer 101, a valve stopper 102, a piston 1, a leaf valve 10, an initial valve 11 and a spacer 13 are assembled to the tip 5a of the piston rod 5 in order from the top in FIG. The piston nut 4 is screwed into a screw portion 5c provided at the tip of the piston rod 5, whereby each member assembled to the piston rod 5 is sandwiched between the step portion 5b of the piston rod 5 and the piston nut 4. It is fixed to the piston rod 5. As described above, by forming the piston 1 in the shape of a bottomed cylinder, a member constituting the valve structure such as a leaf valve can be accommodated in the piston 1, and the piston 1 shown in FIG. The length from the middle upper end to the lower end in FIG. 1 of the piston nut 4 can be shortened, and the piston portion can be reduced in size.

  Subsequently, the leaf valve 10 is configured as a laminated leaf valve by laminating a plurality of annular plates, that is, the annular plates 10a, and the upper surface in FIG. 1 is in contact with the valve seat 1c. . The valve seat 1c is provided with a recessed portion 1f formed by being stamped, and the recessed portion 1f functions as an orifice when the leaf valve 10 is seated on the valve seat 1c. The orifice may be provided by a notch or the like formed on the outer periphery of the leaf valve 10.

  As described above, the leaf valve 10 is assembled to the piston rod 5 together with the piston 1 so that the inner peripheral side is fixedly supported by the piston rod 5 and only the outer peripheral side deflection is allowed to close the port 2 described above. Can be done.

  An annular initial ring 11 whose inner diameter is set larger than the inner diameter of the annular plate 10a and whose outer diameter is set to the same diameter is interposed between arbitrary annular plates 10a among the plurality of annular plates 10a. Has been. The initial ring 11 is concentrically arranged with the annular plate 10a and gives initial deflection to each annular plate 10a stacked on the back side which is lower in FIG. 1 than the initial ring 11, and this initial deflection is given. The annular plate 10a urges each annular plate 10a stacked on the front side, which is the upper side in FIG. 1 from the initial ring 11, in a direction in which the annular plate 10a is seated on the valve seat 1c.

  Furthermore, since the initial ring 11 is not illustrated with any parts on the inner peripheral side in the drawing, it is advisable to provide a means for preventing positional displacement with respect to the annular plate 10a, for example, by welding or bonding. What is necessary is just to make it fix to any one cyclic | annular board 10a among the upper and lower sides in the figure. Further, as a measure for preventing the displacement of the initial ring 11, it is thinner than the annular plate 10a and is slidably fitted to the inner periphery of the initial ring 11, or is loosely fitted and has an inner diameter of the annular plate 10a. Similarly, an annular plate whose inner peripheral side is fixed to the piston rod 5 may be provided.

  That is, since the initial ring 11 is present between the annular plates 10a, an initial deflection is given to any annular plate 10a of the leaf valve 10, so that the valve opening pressure at which the leaf valve 10 is separated from the valve seat 1c is increased. Can do it.

  The valve opening pressure of the leaf valve 10 can be adjusted by the thickness of the initial ring 11 (vertical length in FIG. 1), and when the number of laminated annular plates 10a is 3 or more. Since the number of the annular plates 10a giving the initial deflection can be changed also depending on the location where the initial ring 11 is interposed, it can be adjusted depending on the location where the initial ring 11 is provided.

  Further, the outer diameter of the initial ring 11 may not be the same as the outer diameter of the annular plate 10a but may be set to a small diameter or a large diameter. Consideration is given so that the annular gap between the channels is not too narrow and the channel area is not too small. Furthermore, the number of the annular plates 10a constituting the leaf valve 10 may be set arbitrarily according to the damping characteristic (relationship of the damping force with respect to the piston speed) realized by the present valve structure, and the initial ring 11 depends on the damping characteristic generated in the shock absorber. The outer diameter of each annular plate 10a can be arbitrarily set as long as the initial ring 11 can be interposed.

  Subsequently, the piston nut 4 includes a cylindrical portion 4a and a flange 4b extending from the outer periphery of the lower end in FIG. 1, and the upper end outer periphery of the cylindrical portion 4a has a small diameter to form a small diameter portion 4c. Yes.

  An annular valve restraining member 14 is slidably mounted on the outer periphery of the small diameter portion 4 c of the piston nut 4. The valve restraining member 14 is connected to the valve restraining member 14 and the flange 4 b of the piston nut 4. The leaf spring 10 is in contact with a coil spring 15 interposed therebetween. Therefore, the leaf valve 10 is urged by the coil spring 15 as the urging member via the valve holding member 4, and the bending is suppressed.

  As shown, the valve holding member 14 includes a cylindrical portion 14a and a flange portion 14b provided on the outer periphery of the cylindrical portion 14a. The flange portion 14b supports the lower end of the coil spring 15, and the flange portion 14b. Is in contact with the leaf valve 10. In this embodiment, the sliding length is secured in the axial direction of the valve restraining member 14, and when the outer periphery of the small-diameter portion 4c of the piston nut 4 is moved in the axial direction, rattling occurs and stick slip occurs. Although consideration is given so as not to damage the outer periphery of the small diameter portion 4c, the shape thereof is arbitrary.

  Further, in the above description, the urging member is the coil spring 15. However, since a predetermined urging force may be applied to the leaf valve 10, this may be a disc spring, a leaf spring, or an elastic material such as rubber. It may be a body. In this case, the piston nut 4 is formed in a cylindrical shape and the valve holding member 14 is slidably mounted. However, a separate cylinder is interposed between the piston nut and the spacer 13 so that the valve holding member is held in the cylinder. The member 14 may be attached.

The constructed valve structure in this manner, until the leaf valve 10 is opened, the biasing force of the coil spring 15 biasing the leaf valve 10 is constant does not change, the annular plate 10a as described above The initial valve 11 is given initial deflection, and the leaf valve 10 exhibits an urging force for seating itself on the valve seat 1c by the initial deflection of the annular plate 10a .

When the piston speed, which is the extension speed of the shock absorber, is in the low speed region, the leaf valve 10 is initially deflected to the annular plate 10a and is urged by the coil spring 15, so that the upper chamber 41 and the lower Since the differential pressure in the chamber 42 does not reach the valve opening pressure, the leaf valve 10 is kept seated on the valve seat 1c.

  Then, when the piston speed is low, the hydraulic oil passes from the upper chamber 41 to the lower chamber 42 through the recess 1f that functions as an orifice formed by stamping the valve seat 1c. . Therefore, the damping characteristic at this time is as shown by the solid line in FIG. 2, and in this low speed region, the damping coefficient is relatively large, and the characteristic quickly rises as the piston speed increases. The damping coefficient is larger than the damping coefficient (dashed line in FIG. 2) in the damping characteristic of the conventional valve structure in which the leaf valve is biased by the coil spring while being fixedly supported.

After that, when the piston speed increases and the speed of the piston 1 reaches the middle-high speed region, the difference between the pressure in the upper chamber 41 and the pressure in the lower chamber 42 increases, and the hydraulic oil leaf valve 10 is set in FIG. increased force pushing down the middle downward and overcome the biasing force by the force deflection initial biasing force and the annular plate 10a of the coil spring 15, unseated from the valve seat 1c is bent outer circumferential side of the leaf valve 10 To open port 2.

  Thus, after the leaf valve 10 is bent and opened, the leaf valve 10 exerts an urging force in the direction of closing the port 2 according to the amount of bending, and the leaf spring 10 is bent similarly. As a result, the urging force of the leaf valve 10 in the direction of closing the port 2 is exerted in accordance with the amount of displacement pushed down.

  That is, after the valve is opened, the amount of deflection of the leaf valve 10 increases in proportion to the combined spring constant of the spring constant of the leaf valve 10 and the spring multiplier of the coil spring. Since the valve constants of the valve 10 and the coil spring 15 are lower than the individual spring constants, the damping speed in the middle and high speed region where the leaf valve 10 opens is higher than the damping coefficient in the low speed region as shown by the solid line in FIG. Although the damping force rises in the low speed region, the slope of the damping coefficient in the medium / high speed region is fixed, so that the inner periphery of the leaf valve is fixed and the leaf valve is energized by the coil spring. Becomes smaller than the attenuation coefficient at (a broken line in FIG. 2).

  Therefore, according to this valve structure, the damping characteristics of the shock absorber can be made suitable for vehicle suspension applications, and the riding comfort in the vehicle can be improved.

  Further, the above effect can be obtained only by applying the initial valve 11 to a damping valve in which the conventional valve structure is embodied, so that the manufacturing cost is not significantly increased and the economy is sacrificed. Nor.

  A structure in which the leaf valve 10 is mounted directly on the outer periphery of the piston rod 5 is employed, and the leaf valve 10 or the like is attached to the piston rod 5 as compared with a valve structure in which the leaf valve is lifted from the piston. It becomes easy.

  Further, since it is not necessary to secure the valve opening pressure of the leaf valve 10 by using the coil spring 15 having a long natural length compressed at a large compression ratio, the total length of the valve structure is not lengthened, and the buffer is not buffered. This does not cause a problem that the stroke length, which is the extendable range of the device, is shortened, and the mounting property on the vehicle is not deteriorated.

Furthermore, even if the spring constant of the coil spring 15 is set low, the valve opening pressure of the leaf valve 10 can be adjusted by the initial ring 11, and the valve opening of the leaf valve 10 is performed by the urging force due to the initial deflection of the annular plate 10a. If the majority of the pressure is applied, the length of the coil spring 15 can be avoided, and the damping coefficient when the piston speed is in the middle to high speed range is further reduced, so that the damping characteristic is ideal. Therefore, the ride comfort in the vehicle can be further improved without sacrificing economy and stroke length.

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

  Although the description of the embodiment of the valve structure is finished as described above, the valve structure of the present invention may be embodied in the compression side damping valve of the piston portion of the shock absorber. Of course, the present invention can be embodied in a base valve section that partitions the reservoir, and can be applied to a valve that functions as a damping force generating element that generates a damping force.

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

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

DESCRIPTION OF SYMBOLS 1 Piston 1a which is a valve disc Bottom 1b Insertion hole 1c Valve seat 1d, 2 Port 1e Tube 1f Recess 3 Window 4 Piston nut 4a Piston nut 4b Piston nut flange 4c Piston nut small diameter portion 5 Piston rod 5a Piston rod End 5b of piston rod Step portion 5c of piston rod Screw portion 13, 101 of piston rod Spacer 10 Leaf valve 10a Annular plate 11 of leaf valve Initial valve 14 Valve restraining member 14a Tube portion 14b of valve restraining member Gutter portion 15 of valve restraining member Coil spring 40 as an urging member Cylinder 41 Upper chamber 42 Lower chamber 100 Pressure side leaf valve 102 Valve stopper

Claims (1)

Closing a valve disc, a deflection of the inner periphery is fixedly supported outer periphery an annular is allowed the port while being stacked on the valve disk port with the piston rod axis portion is inserted is formed a leaf valve that, the valve disc and the leaf valve and the piston nut fixed to the piston rod, and a suppressing coil spring deflection of the leaf valve by energizing the leaf valve in a direction for closing the port In the provided valve structure,
The leaf valve is configured by stacking a plurality of annular plates mounted directly on the outer periphery of the piston rod,
Interposing an annular initial ring whose inner diameter is set to be larger than the inner diameter of the annular plate between arbitrary annular plates , the initial deflection is given to the annular plate laminated on the back side of the initial ring,
A valve structure characterized in that an opening pressure of the leaf valve is set by an urging force due to an initial deflection of the annular plate and an urging force of the coil spring .

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