JP4839199B2 - Damping force generator for hydraulic shock absorber - Google Patents

Description

  The present invention relates to a damping force generating device in a hydraulic shock absorber, and in particular, in a cylindrical hydraulic shock absorber in which a rod body is inserted so as to be able to protrude and retract, the rod body protrudes from the cylinder body with a large stroke. In the hydraulic shock absorber having a collision preventing means for preventing the piston portion held by the rod body from colliding with a bearing member that penetrates the rod body while sealing the opening end of the cylinder body at the time of extending operation The present invention relates to an improvement of a damping force generator.

  In a cylindrical hydraulic shock absorber in which a rod body is inserted into the cylinder body so as to be able to appear and retract, the piston portion held by the rod body at the time of full extension operation in which the rod body protrudes from the cylinder body with a large stroke is the cylinder body. For example, Patent Literature 1 discloses a hydraulic shock absorber having a collision prevention means for preventing a collision with a bearing member that penetrates a rod body while sealing an opening end of the rod.

  That is, in the collision prevention structure disclosed in Patent Document 1, for example, as shown in FIG. 3, a cylindrical hydraulic shock absorber in which a rod body 2 is inserted into a cylinder body 1 so as to be able to protrude and retract. 2, the bearing member 11 that seals the opening end that is the upper end of the cylinder body 1 and passes the rod body 2 through the shaft core portion is formed of a coil spring that is also called an extension spring disposed in the cylinder body 1. The prevention means 3 is held.

  On the other hand, in this hydraulic shock absorber, the piston body 41 that constitutes the piston portion 4 that is fixedly held by the distal end portion 2a that is the lower end portion of the rod body 2 that resides in the cylinder body 1 is the cylinder body. It is assumed that an expansion side chamber R1 and a compression side chamber R2 are defined in the cylinder body 1 while being slidably accommodated in the cylinder 1.

  The oil buffer has a compression side damping valve 42 that closes the downstream end of the compression side port 41a opened in the piston body 41 so as to be openable and closable, and is fixed to the distal end portion 2a of the rod body 2. The valve stopper 43 that restricts the valve opening degree of the pressure side damping valve 42 by restricting the lift amount of the outer side of the pressure side damping valve 42 at the outer circumference side portion.

  Therefore, in the hydraulic shock absorber disclosed in Patent Document 1 described above, that is, as shown in FIG. 3, the piston portion is in a fully extended operation in which the rod body 2 protrudes from the cylinder body 1 with a large stroke. 4, that is, in the drawing, the collision preventing means 3 made of a coil spring prevents the valve stopper 43 constituting the piston portion 4 from colliding with the bearing member 11.

In addition, in the place indicated by above-mentioned patent document 1, it is supposed that it has cushion rubber other than the above-mentioned coil spring, and this cushion rubber also functions as the collision preventing means 3.
JP 2003-194128 A (see FIG. 1)

  However, in the hydraulic shock absorber disclosed in Patent Document 1 described above, ie, shown in FIG. 3, there is no problem with preventing the collision at the time of the fully extended operation of the hydraulic shock absorber. There is a concern that there is a slight problem with the generation of the compression side damping force by the damping valve 42.

  That is, in the above-described hydraulic shock absorber, the valve stopper 43 approaches and contracts the coil spring as the collision preventing means 3 when the rod body 2 protrudes from the cylinder body 1 with a large stroke when it is fully extended. It is said.

  Therefore, when the hydraulic shock absorber is in the fully extended state, the axial force, which is the spring force of the coil spring, acts on the rod body 2 via the valve stopper 43 even in a so-called stationary state.

  From this, when the hydraulic shock absorber in the most extended state starts contracting operation, the rod body 2 is applied with an axial force as a spring force of the coil spring in addition to the so-called axial force due to an external load. It will be.

  Therefore, when the most extended hydraulic shock absorber starts the contraction operation, the damping force generated by the compression side damping valve 42 tends to be insufficient, which may be pointed out.

  Incidentally, the damping force generated by the compression side damping valve 42 is set to be high on the premise that the spring force of the coil spring as the collision preventing means 3 acts on the rod body 2 as an axial force when the hydraulic shock absorber is in the maximum extension state. Then, the so-called normal time damping force where the spring force of the coil spring does not act becomes too high.

  The present invention was devised in view of such a current situation, and the object of the present invention is not only to enable collision prevention when the hydraulic shock absorber is fully extended, but also to achieve the maximum extension. When the hydraulic shock absorber in the state starts contracting operation, the pressure side damping force generated by the pressure side damping valve provided in the piston portion in the cylinder body is not deficient. It is an object of the present invention to provide an anti-collision structure that is optimal for expecting an improvement of the above.

In order to achieve the above-described object, the means of the present invention includes a bearing member that seals an open end of a cylinder body, a rod body that penetrates the bearing member into the cylinder body and is inserted through the bearing member, A piston body held at the tip of the rod body, a pressure side chamber and an extension side chamber defined in the cylinder body by the piston body, and a pressure side port formed in the piston body to communicate the pressure side chamber and the extension side chamber And a pressure-side damping valve provided at the outlet end of the pressure-side port so as to be opened and closed, a valve stopper laminated on the pressure-side damping valve, and the bearing member and the valve stopper. In a hydraulic shock absorber having a collision preventing means for preventing a collision between a valve stopper and a piston body with respect to a bearing member by a spring force, a biasing hand is interposed between the bearing member and the compression side damping valve. The lower end of the urging means is supported on the outer peripheral side portion of the compression side damping valve while the upper end of the urging means is opposed to the bearing member, and the lower end of the collision preventing means is seated on the valve stopper when fully extended. While the upper end of the urging means is seated on the bearing member and the urging means is contracted, the valve opening degree of the compression side damping valve is controlled by the spring force of the urging means. The upper end of the urging means is separated from the bearing member during a contraction operation in which the rod body is immersed in the body.

  Therefore, in the present invention, since the collision prevention means is provided, the piston portion is not caused to collide with the bearing member when the hydraulic shock absorber is fully extended so that the rod body protrudes from the cylinder body with a large stroke. It becomes possible.

Then, in the present invention, since providing the biasing means for supporting the lower end while facing the upper end to the bearing member on the outer peripheral side of the compression side damping valve, biasing means is most extended state of the hydraulic shock absorber The valve opening degree of the compression side damping valve is controlled by the spring force that is contracted during the fully extended operation.

  As a result, even when the hydraulic shock absorber in the most extended state starts contracting operation, even if the axial force from the collision prevention means acts on the rod body in addition to the axial force due to an external load, the compression side damping By reducing the valve opening degree of the valve, the damping force generated by the compression side damping valve can be increased.

For this reason, when the hydraulic shock absorber is in the fully extended state, the damping force generated by the compression side damping valve must be set high so that the spring force from the collision preventing means acts on the rod body as an axial force. In other words, it is possible to prevent the damping force during so-called normal time from being excessively high except when the spring force of the collision preventing means does not act .

Hereinafter, the present invention will be described based on the illustrated embodiment. A damping force generating device in a hydraulic shock absorber according to the present invention is embodied in a cylindrical hydraulic shock absorber as shown in FIG. Basically, it has the same configuration as that shown in FIG.
That is, the hydraulic shock absorber according to this embodiment includes a bearing member 11 that seals the opening end of the cylinder body 1 and a rod body that is inserted into the cylinder body 1 so as to be able to protrude and retract. 2, a piston body 41 held at the tip of the rod body 2, a compression side chamber R 2 and an extension side chamber R 1 defined in the cylinder body 1 by the piston body 41, and the piston body 41. A pressure side port 41a communicating the pressure side chamber R2 and the extension side chamber R1, a pressure side damping valve 42 provided at the outlet end of the pressure side port 41a so as to be openable and closable, a valve stopper 43 stacked on the pressure side damping valve 42, and Collision prevention that interposes between the bearing member 11 and the valve stopper 43 to prevent the valve stopper 43 and the piston body 41 from colliding with the bearing member 11 with a spring force when fully extended. It is made of and means 3.
In this embodiment, the urging means 5 comprising a coil spring is provided between the bearing member 11 and the compression side damping valve 42 so that the tip as the upper end of the urging means 5 faces the bearing member 11. However, the base end, which is the lower end, is carried on the outer peripheral side portion of the compression side damping valve 42, and the tip, which is the lower end of the collision preventing means 3, is seated on the valve stopper 43 and the urging means 5 at the time of full extension operation. The valve opening of the compression side damping valve 42 is controlled by the spring force of the urging means 5 while the upper end of the urging means 5 is seated on the bearing member 11 and the urging means 5 is contracted.
Further, the upper end of the urging means 5 is separated from the bearing member 11 when the rod body 2 is retracted into the cylinder body 1 from the fully extended state.

  That is, in the illustrated hydraulic shock absorber, the rod body 2 is inserted into the cylinder body 1 so as to be able to protrude and retract, and the piston portion 4 is held by the tip portion 2a of the rod body 2 that is present in the cylinder body 1. It is supposed to become.

  At this time, the opening end, which is the upper end of the cylinder body 1 in the figure, is sealed with the bearing member 11, and the rod body 2 penetrates the shaft core portion of the bearing member 11. Is provided with a collision preventing means 3 made of a coil spring, which may be called an extension spring, under the holder member 31.

  Incidentally, in the coil spring as the collision preventing means 3, the holder member 31 holds the base end that is the upper end in the figure, and the tip that is the lower end in the figure is downward in the so-called normal time. It is assumed that it is opposed to a certain valve stopper 43 so as to be separable.

  Therefore, in this hydraulic shock absorber, when the rod body 2 protrudes from the cylinder body 1 with a large stroke, the coil spring is contracted by the adjacent valve stopper 43 during the extending operation. At this time, the piston portion 4 can be prevented from colliding with the bearing member 11 by the spring force of the coil spring.

  By the way, in this hydraulic shock absorber, the piston part 4 is slidably accommodated in the cylinder body 1 and is composed of a piston body 41 constituting the piston part 4 in the cylinder body 1 and the expansion side chamber R1 and the pressure side chamber. A pressure side damping valve 42 that defines R2 and that opens and closes the downstream side end that becomes the upper side end in the drawing of the pressure side port 41a opened in the piston body 41 and opens to the extension side chamber R1 is provided. It is going to be.

  The piston body 41 is also opened with an extension side port (not shown), and the downstream end of the extension side port that opens to the pressure side chamber R2 is closed so that the extension side damping valve 44 can be opened and closed. It is supposed to be done.

  The compression-side damping valve 42 and the expansion-side damping valve 44 are, as shown in the figure, formed by laminating a plurality of annular leaf valves having different diameters, and are arranged freely at the outer peripheral end by fixing the inner peripheral end. That is, the inner peripheral side portions (not shown) of the damping valves 42 and 44 are fixed to the boss portions (not shown) of the piston body 41, and the outer peripheral side portions (not shown) are seat portions (not shown) of the piston body 41. It is supposed to be sitting on and off.

  Therefore, in this hydraulic shock absorber, when the piston portion 4 slides in the cylinder body 1, the hydraulic oil between the expansion side chamber R1 and the pressure side chamber R2 via the damping valves 42, 44 is obtained. The reciprocation is enabled, and a predetermined damping force is generated by each of the damping valves 42 and 44.

  On the other hand, in the piston portion 4 in this hydraulic shock absorber, as described above, the amount of deflection of the outer peripheral side portion of the pressure side damping valve 42, that is, the lift amount is regulated so as to face the back surface of the pressure side damping valve 42 described above. It has a valve stopper 43 to be used.

  The main components of the valve stopper 43, the pressure side damping valve 42, the piston body 41, and the extension side damping valve 44 are the stepped portion 2c and the tip portion formed between the tip portion 2a and the shaft portion 2b of the rod body 2. It is assumed that it is sandwiched between a piston nut 45 that is screwed into a screw-like portion (not shown) that is an extension of 2a.

  Therefore, in the illustrated hydraulic shock absorber, the valve stopper 43, the compression side damping valve 42, the piston body 41, and the extension side damping valve 44, which are the main components described above, are fixedly held by the rod body 2. In particular, the valve stopper 43 functions as a part of the rod body 2 in view of the relationship with the coil spring 3 as a collision preventing means described later.

  By the way, in the damping force generating device in the hydraulic shock absorber according to the present invention, the biasing means 5 for supporting the base end on the outer peripheral side portion of the compression side damping valve 42 while the tip end faces the bearing member 11 so as to be separable. At the same time, the biasing means 5 is contracted by being seated on the bearing member 11 when the biasing means 5 is fully extended, and the valve opening degree of the compression side damping valve 42 is controlled by the spring force provided.

  That is, as shown in the figure, the urging means 5 is formed of a coil spring, and the base end which is the lower end in the figure is made the spring receiving member 51 while the front end which is the upper end in the figure is opposed to the bearing member 11 so as to be separable. It is assumed that it is carried on the outer peripheral side portion of the compression side damping valve 42 under the intervening state.

  At this time, it is assumed that the spring receiving member 51 is interposed on the outer periphery of the valve stopper 43 under a lift amount restricting structure. As shown in FIG. A hook-like projecting portion 43a is provided at the upper end where the tip of the coil spring contacts, and the amount of lift of the spring receiving member 51, that is, the amount of movement of the compression side damping valve 42 in the lift direction by the projecting portion 43a. Is adopted.

  By the way, in the urging means 5 according to the present invention, the spring force possessed by the collision preventing means 3 acts on the rod body 2 as an axial force. When starting, the rod body 2 is immersed in the cylinder body 1 with an axial force greater than that set in the compression side damping valve 42. As a result, the damping force generated by the compression side damping valve 42 is insufficient. It is supposed to be arranged to prevent it from becoming a tendency to do so.

  Then, as a specific measure for preventing the damping force from being insufficient, the valve opening degree in the compression side damping valve 42 is controlled, that is, the valve opening degree is reduced, and the flow path resistance when the hydraulic oil passes through. I try to make it bigger.

  Therefore, in the present invention, since the above-described damping force is prevented from being deficient, a measure for setting the damping force generated by the compression side damping valve 42 to be high in advance is not adopted. There is no need to worry that the damping force during so-called normal time when the spring force is not acting will be too high.

  Incidentally, by disposing the urging means 5, the tip of the coil spring is contracted close to the bearing member 11 when the rod body 2 protrudes from the cylinder body 1 with a large stroke. At this time, the outer peripheral side portion of the compression side damping valve 42 tends to come into pressure contact with the seat portion of the piston body 41 by the spring force of the coil spring. As a result, the cracking pressure in the compression side damping valve 42 is reduced. Thus, a high damping force commensurate with the axial force from the collision preventing means 3 in addition to the axial force caused by the external load is generated on the rod body 2.

  In the present invention, the spring force of each of the collision preventing means 3 and the urging means 5 is generated when the rod body 2 protrudes from the inside of the cylinder body 1 with a large stroke, and the piston force is generated. Since the portion 4 is prevented from colliding with the bearing member 11, a more reliable collision prevention function can be exhibited.

  By the way, as to the timing of expansion and contraction in the collision preventing means 3 and the urging means 5, as far as the present invention intends, as long as the tip of the collision preventing means 3 is in contact with the valve stopper 43, it is not necessary. It can be said that it is preferable that the tip of the biasing means 5 is not separated from the bearing member 11.

  However, immediately before the tip of the collision prevention means 3 is separated from the valve stopper 43, the collision prevention means 3 has almost no spring force, and therefore there is no situation in which an axial force acts on the rod body 2. You can see it.

  If this is the case, it can be said that the front end of the urging means 5 may be separated from the bearing member 11 immediately before the front end of the collision preventing means 3 is separated from the valve stopper 43.

  However, when the tip of the biasing means 5 is not to be separated from the bearing member 11 even after the tip of the collision preventing means 3 is separated from the valve stopper 43, the contraction operation is started from the maximum extension state. Since the cracking pressure in the compression side damping valve 42 is increased, even when the hydraulic pressure in the compression side chamber R2 tends to decrease compared to the normal time for some reason at the start of the contraction operation, the predetermined pressure by the compression side damping valve 42 is obtained. The generation of the compression side damping force can be expected.

  In the above description, the valve stopper 43 embodying the present invention regulates the lift amount, which is the amount of bending of the outer peripheral side portion of the compression side damping valve 42. However, according to the intention of the present invention, the valve stopper 43 Of course, it may be set so as not to be related to the regulation of the lift amount of the compression side damping valve 42, and the operation and effect in that case are not different.

1 is a partial half-longitudinal longitudinal sectional view showing a hydraulic shock absorber embodying a collision preventing structure according to the present invention in a partially broken view. It is a figure which shows the operating state of the collision prevention structure in the hydraulic shock absorber of FIG. 1 similarly to FIG. It is a figure which shows the hydraulic shock absorber which actualized the collision prevention structure as a prior art example similarly to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder body 2 Rod body 3 Collision prevention means 4 Piston part 5 Energizing means 11 Bearing member 41 Piston body 41a Pressure side port 42 Pressure side damping valve 43 Valve stopper R1 Extension side chamber R2 Pressure side chamber

Claims (5)

A bearing member that seals the opening end of the cylinder body, a rod body that penetrates the bearing member through the bearing member so as to be able to protrude and retract, a piston body that is held at the tip of the rod body, and the piston A pressure side chamber and an extension side chamber defined in the cylinder body by a body, a pressure side port formed in the piston body to communicate the pressure side chamber and the extension side chamber, and a pressure side provided openably at the outlet end of the pressure side port The damping valve, the valve stopper laminated on the compression side damping valve, and the bearing member and the valve stopper are interposed between the valve member and the valve stopper so that the collision between the valve stopper and the piston body with respect to the bearing member is caused by the spring force when the extension member is fully extended. In the hydraulic shock absorber having a collision preventing means for preventing, an urging means is provided between the bearing member and the compression side damping valve, and an upper end of the urging means is opposed to the bearing member. The lower end is supported on the outer peripheral side of the compression side damping valve while the lower end of the collision preventing means is seated on the valve stopper and the upper end of the urging means is seated on the bearing member during the fully extending operation. The valve opening of the compression side damping valve is controlled by the spring force of the biasing means while contracting the biasing means, and further, the biasing means during the contracting operation in which the rod body is immersed in the cylinder body from the fully extended state. A damping force generating device in a hydraulic shock absorber, wherein an upper end of the hydraulic shock absorber is separated from the bearing member . 2. The damping force generating device for a hydraulic shock absorber according to claim 1, wherein the collision preventing means is formed of a coil spring and the distal end of the collision preventing means is opposed to the valve stopper so as to be separable while being held by the bearing member. The biasing means comprises a coil spring and the base end is supported on the outer peripheral side of the compression side damping valve with the spring receiving member disposed, and the spring receiving member is placed on the outer periphery of the valve stopper on the outer peripheral side of the compression side damping valve. The damping force generating device for a hydraulic shock absorber according to claim 1 or 2, wherein the damping force generating device is movably mounted on the hydraulic shock absorber. 4. The claim 1, claim 2 or claim 3, wherein the tip of the urging means is separated from the bearing member when the tip of the collision preventing means is separated from the valve stopper by a contraction operation in which the rod body is immersed in the cylinder body. A damping force generator for a hydraulic shock absorber according to claim 1. The pressure side damping valve is composed of an annular leaf valve, and the downstream end of the pressure side port for opening is closed so as to be openable and closable at the outer peripheral side of the piston body constituting the piston portion. Or the damping-force generator in the hydraulic buffer of Claim 4.

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