JP5027563B2 - Check seal structure - Google Patents

Description

  The present invention relates to a check seal structure.

  In general, a multi-cylinder type hydraulic shock absorber includes a rod guide that closes the opening end of the cylinder and the opening end of the outer cylinder covering the cylinder and supports a rod that is movably inserted into the cylinder. The rod guide is laminated with an annular insert metal having a seal member on each of the inner periphery and the outer periphery to keep the hydraulic shock absorber oil-tight.

  In such a double cylinder type hydraulic shock absorber, the rod and the rod guide are not completely sealed, so the rod guide and the insert pass between the rod and the rod guide. It is necessary to return the hydraulic oil flowing into the space between the metal to the reservoir, and the rod guide is provided with a communication hole that communicates the space and the reservoir formed between the cylinder and the outer cylinder. ing.

  However, if the space and the reservoir communicate with each other without limitation, gas may enter the cylinder from the reservoir side. Therefore, in the hydraulic shock absorber, a rubber called a check seal is formed on the lower surface of the insert metal. The annular valve body formed in the above is seated on the upper surface of the rod guide. This check seal cuts off the communication between the communication hole and the space, and acts to bend when the pressure in the space increases and to connect the space to the reservoir and return the hydraulic oil from the space to the reservoir.

  After the check seal is opened by the pressure in the space acting on the inner peripheral surface (hereinafter simply referred to as “internal pressure”) and the hydraulic oil is returned to the reservoir, the check pressure is reduced from the reservoir side on the outer peripheral surface as the internal pressure decreases. It receives pressure (hereinafter referred to simply as “external pressure”) and is pressed to the rod guide side, again blocking the communication between the space and the reservoir, allowing only the flow of hydraulic oil from the space to the reservoir It is designed to function as a check valve.

  However, when such a check seal is provided, the above internal pressure is inevitably increased to the valve opening pressure of the check seal. Since the tightening force of the oil lip increases and the sliding resistance of the rod increases, the check seal is required to be opened with a minimum internal pressure.

  In order to satisfy this requirement, the flexural rigidity of the check seal can be reduced. However, in this case, the check seal is warped to the inner peripheral side due to the external pressure from the reservoir side, and the function as the check valve is impaired. Therefore, it is desirable to develop a check seal that can withstand a large external pressure while reducing the valve opening pressure as much as possible. As one measure, contact the rod guide from the tip of the check seal to the middle. In addition, a check seal structure has been proposed in which a plurality of concavities and convexities that engage with each other are provided at contact portions of both the check seal and the rod guide (see, for example, Patent Document 1).

With this proposed check seal structure, it is possible to withstand a large external pressure by engaging the check seal and the plurality of projections and depressions provided on the rod guide while maintaining the valve opening pressure, and to prevent the check seal from curling. it can.
JP 09-317914 A (FIG. 3)

In order to achieve the above-described object, the problem solving means in the present invention is configured to close the opening end of the cylinder in the hydraulic shock absorber and the opening end of the outer cylinder covering the cylinder, and pivot the rod that is movably inserted into the cylinder. A rod guide to be supported, an annular insert metal stacked on the rod guide, and a space between the rod guide and the insert metal formed between the cylinder and the outer cylinder by contacting the rod guide provided on the insert metal. In a check seal structure having an annular check seal that allows only the flow of hydraulic oil toward the reservoir, a protrusion that abuts the rod guide is provided at the tip of the check seal, and the rod guide is engaged with the protrusion to check the seal. Is provided with a step that restricts the return to the inner peripheral side of the check seal. Molded from the contact portion to cause the rod guide so that the range to the root portion continuous to the insert metal, also has the protrusion opposing surfaces of the rod guide serving as a seat portion facing the inner circumferential surface of the check seal It is characterized by being set so as to follow the inclination of the check seal in the state in contact with the rod guide.

  That is, in the conventionally proposed check seal, since the tip end to the intermediate portion of the check seal are in close contact with the end surface of the rod guide, the pressure receiving surface that receives the internal pressure of the check seal is from the root portion connected to the insert metal. The check seal cannot be opened unless the pressure receiving area is secured and a large internal pressure is applied to a narrow range up to the intermediate portion.

  In addition, when the check seal receives internal pressure at the pressure receiving surface and a gap is formed between the contact portion from the tip to the intermediate portion of the check seal and the end surface of the rod guide, this time, the inner peripheral surface of the check seal Is the pressure in the space because the entire pressure receiving surface is subjected to internal pressure, the area of the pressure receiving surface (hereinafter simply referred to as “pressure receiving area”) is rapidly expanded, and the check seal is suddenly opened. The internal pressure drops rapidly, and the check seal closes rapidly due to the influence.

  As described above, if the pressure receiving area for receiving the internal pressure in the check seal is not sufficiently secured, the opening operation and the closing operation of the check seal are vibrated repeatedly, and the check seal is subjected to vibration stress and is subjected to a durable surface. In addition, the check seal valve opening and closing operations may be vibrated and the internal pressure in the space may fluctuate more and the rod's sliding resistance may become unstable and buffered. There is a possibility that stable and smooth expansion and contraction of the vessel cannot be compensated.

  Therefore, the present invention was devised to improve the above-described problems, and the object of the present invention is to withstand a large external pressure by opening the valve with a small internal pressure while ensuring a sufficient pressure receiving area for receiving the internal pressure. It is to provide a check seal structure that is possible.

  In order to solve the above-described object, the problem solving means in the present invention is configured to close the opening end of the cylinder in the hydraulic shock absorber and the opening end of the outer cylinder covering the cylinder, and pivot the rod that is movably inserted into the cylinder. A rod guide to be supported, an annular insert metal stacked on the rod guide, and a space between the rod guide and the insert metal formed between the cylinder and the outer cylinder by contacting the rod guide provided on the insert metal. In a check seal structure including an annular check seal that allows only the flow of hydraulic oil toward the reservoir, a protrusion that contacts the rod guide is provided at the tip of the check seal, and the rod guide is engaged with the protrusion of the check seal. A step was provided to restrict the check seal from curving toward the inner periphery.

According to the check seal structure of the present invention, since the pressure receiving area is sufficiently secured, not only the valve opening operation can be reliably performed with a small internal pressure, but the valve opening operation and the valve closing operation are not vibrated. No stress is applied and deterioration of the check seal is not promoted.
That is, the pressure-receiving surface on the valve opening side of the check seal is formed so as to be in the range from the contact portion of the protrusion to the rod guide to the root portion connected to the insert metal, so the pressure-receiving surface that receives the internal pressure in the space Compared with the conventional check seal structure, the range can be made very large, the pressure receiving area can be secured sufficiently large, and the valve can be opened with a smaller internal pressure than the conventional check seal structure.
In this way, since the pressure receiving surface that receives the internal pressure can be set in a wide range, there is no fluctuation in the pressure receiving area immediately before and after the valve opening operation, so that the valve opening operation and the valve closing operation are abruptly and oscillatory. It will never be.

  In addition, since there is no inconvenience that the internal pressure fluctuates due to the repeated vibrations of the check seal opening and closing operations, the oil lip tightening force does not fluctuate. The sliding resistance of the rod is stabilized, and it becomes possible to compensate for the stable and smooth expansion / contraction operation of the hydraulic shock absorber.

In addition, this check seal structure can withstand a large external pressure by engaging the check seal protrusion and the step, and coupled with the fact that the valve can be reliably opened with a small internal pressure, increasing the degree of freedom in designing the check seal. The versatility of the check seal is also improved.
In addition, the opposing surface, which is the seat part of the rod guide, is set so as to follow the inclination of the check seal, so that the force acting on the check seal is The entire seal is pressed against this facing surface, and the check seal is in close contact with this facing surface to reliably prevent the backflow of gas and hydraulic oil from the reservoir to the space. The warp of the seal is also prevented, and further, since the bending point where stress concentrates on the root portion and the middle portion of the check seal is not generated, the life of the check seal can be further extended.

  Hereinafter, the check seal structure of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a head portion of a hydraulic shock absorber in which a check seal structure according to an embodiment is embodied. FIG. 2 is an enlarged longitudinal sectional view of a head portion of a hydraulic shock absorber in which a check seal structure according to an embodiment is embodied. FIG. 3 is an enlarged longitudinal sectional view of a head portion of a hydraulic shock absorber in which a check seal structure according to a modification of the embodiment is embodied. FIG. 4 is an enlarged longitudinal sectional view of a head portion of a hydraulic shock absorber in which a check seal structure according to another modification of the embodiment is embodied.

  As shown in FIG. 1, the check seal structure in one embodiment is embodied in the upper end portion of a cylinder that is a head portion of a hydraulic shock absorber. Specifically, the hydraulic shock absorber is disposed outside the cylinder 1, the outer cylinder 2 that covers the cylinder 1 and closes the opening end of the cylinder 1 and the opening end of the outer cylinder 2, and the cylinder 1. A rod guide 4 that pivotally supports a rod 3 that is movably inserted into the rod guide 4 and an annular insert metal 5 that is stacked on the rod guide 4 are provided. 3 is slidably inserted into the cylinder 1 so that a rod-side chamber R1 filled with hydraulic fluid in the cylinder 1 and a piston-side chamber outside the figure are partitioned. A reservoir R filled with gas and hydraulic oil is formed between the outer cylinder 2.

  The rod guide 4 is formed in an annular shape, and is provided so that a convex portion 4a protrudes downward from the lower end in FIG. 1, and this convex portion 4a fits into the opening end that is the upper end in FIG. The upper end of the cylinder 1 is closed. Moreover, the rod guide 4 is inserted in the inner peripheral side of the opening end used as the upper end in FIG. 1 of the outer cylinder 2, and also obstruct | occludes the upper end of the outer cylinder 2. FIG.

  Further, a cylindrical slide bearing 6 is mounted on the inner periphery of the rod guide 4, and the rod 3 is slidably inserted into the slide bearing 6. Further, the rod guide 4 is provided with a recess 4b on the inner peripheral side at the upper end in FIG. 1 and a step 4e continuous to the outer periphery of the recess 4b, and a notch 4c is provided on the outer periphery at the upper end in FIG. A communication hole 4d that communicates from the outer edge of the stepped portion 4e to the surface facing the reservoir R of the rod guide 4 is provided.

  Further, as shown in FIGS. 1 and 2, the inner peripheral portion of the stepped portion 4 e protrudes toward the insert metal 5, and the upper surface of the inner peripheral portion is an inclined surface, and a check seal 9 described later on the inner peripheral portion. Is formed, and a step 4g is provided in the middle of the seat portion 4f so that the inner peripheral side of the seat portion 4f becomes higher.

  Next, the insert metal 5 laminated on the upper side of the rod guide 4 in FIG. 1 has an annular and flat plate shape, an inner peripheral seal 7 that is in sliding contact with the outer periphery of the rod 3 on the inner periphery thereof, and an outer periphery thereof. An outer peripheral seal 8 accommodated in the notch 4c of the rod guide 4 and in close contact with the outer periphery of the outer cylinder 2, and a check seal 9 are integrally held on the lower surface in FIG.

  The inner peripheral seal 7 includes a dust lip 7a slidably contacting the upper side of the rod 3 in FIG. 1 and an oil lip 7b slidably contacting the lower side of the rod 3 in FIG. Seal the gap. On the other hand, the outer peripheral seal 8 seals between the insert metal 5 and the outer cylinder 2.

  The insert metal 5 is fixed to the outer cylinder 2 while being pressed against the rod guide 4 side by crimping the opening end of the outer cylinder 2 to the inner peripheral side, and the opening ends of the cylinder 1 and the outer cylinder 2 are connected to each other. Sealing is performed to maintain the cylinder 1 and the outer cylinder 2 in a sealed state.

  When the insert metal 5 is stacked on the rod guide 4, a space A is formed between the insert metal 5 and the recess 4 b provided on the upper surface side of the rod guide 4 in FIG. 1. In this space A, when the hydraulic shock absorber expands and contracts, the hydraulic oil that adheres to the outer periphery of the rod 3 and passes above the rod guide 4 through the sliding gap between the rod 3 and the slide bearing 6 is retained. It is scraped off by the inner peripheral seal 7 and left behind. When the expansion and contraction of the hydraulic shock absorber is repeated, the hydraulic oil that is gradually left behind is accumulated in the space A.

  Therefore, in order to return the hydraulic oil accumulated in the space A to the reservoir R in this way and prevent the gas in the reservoir R from leaking into the space A, the lower surface of the insert metal 5 is shown in FIG. As shown in FIG. 2, an annular check seal 9 that abuts against the seat portion 4 f of the rod guide 4 and divides the space A from the reservoir R is provided.

  The check seal 9 has a base end that is the upper end in FIG. 1 integrated with the lower surface of the insert metal 5 in FIG. 1 by welding, bonding, or the like. It is integrated.

  In integrating the inner peripheral seal 7, the outer peripheral seal 8, and the check seal 9 into the insert metal 5, specifically, for example, the insert metal 5 is placed in a mold that forms the inner peripheral seal 7, the outer peripheral seal 8, and the check seal 9. Is inserted, the material of each of the seals 7, 8, 9 is heated, put into the mold and pressed to mold each of the seals 7, 8, 9 and integrated with the insert metal 5. Each of the seals 7, 8, and 9 may be integrated with the insert metal 5 without using such a molding method.

  The check seal 9 is formed in an annular shape and has a protrusion 9a at the tip, and extends from the lower surface of the insert metal 5. The protrusion 9a at the tip is stepped by the sheet portion 4f of the rod guide 4 by its own elasticity. It is pressed and contacted to the outer peripheral side from 4g.

  Further, as shown in the drawing, in the state where the protrusion 9 a of the check seal 9 is in contact with the sheet portion 4 f of the rod guide 4, the sheet portion 4 f that is an opposing surface facing the inner peripheral surface of the check seal 9 in the rod guide 4. The inner peripheral side surface s is set along the inclination of the check seal 9, and when the protrusion 9 a of the check seal 9 is in contact with the seat portion 4 f of the rod guide 4, The peripheral side surface s is set so as to be substantially parallel to the inner peripheral surface of the check seal 9.

  Since the check seal 9 is bent in this way to generate a resilient force and its tip abuts against the seat portion 4f of the rod guide 4, the check seal 9 is placed in the reservoir R via the communication hole 4d. In addition to preventing the sealed gas from flowing into the space A, conversely, when the hydraulic oil accumulates in the space A and the pressure in the space A rises, it functions to bend and release the hydraulic oil to the reservoir R. .

  That is, the check seal 9 basically functions as a check valve that allows only the flow of hydraulic oil from the space A to the reservoir R, and the hydraulic oil is accumulated to some extent in the space A, and the pressure in the space A When the pressure rises, it is bent by the pressure, away from the rod guide 4, communicates the space A to the communication hole 4 d, and returns the hydraulic oil to the reservoir R. The protrusion 9 a provided at the tip of the check seal 9 Since the valve is brought into contact with the seat portion 4f and closed, the pressure receiving surface that receives the internal pressure in the space A is conventionally connected from the base portion 9b of the check seal 9 to the contact portion of the protrusion 9a with the seat portion 4f. Compared to the check seal structure, it can be made a very large range, the pressure receiving area can be secured sufficiently large, and in addition, the contact area of the contact part is a leap compared to the conventional check seal Since decreases, it can be opened with a small pressure by comparing a check seal 9 to the conventional check seal structure.

  In the check seal 9, the pressure receiving surface that receives the internal pressure can be set in a wide range from the base portion 9 b of the check seal 9 to the contact portion of the protrusion 9 a with the seat portion 4 f. Since the pressure receiving area does not change immediately before and after the valve operation, the valve opening operation and the valve closing operation do not become abrupt and oscillating.

  As described above, the check seal 9 can be opened with a small internal pressure, but conversely, an external pressure that causes the check seal 9 to warp from the reservoir R side to the inner peripheral side on the outer peripheral side. When acting, the protrusion 9a at the tip of the check seal 9 is engaged with the step 4g provided on the inner peripheral side from the contact portion of the sheet portion 4f, and the warping of the check seal 9 toward the inner peripheral side is restricted.

  That is, even if the external pressure becomes abnormally high, the protrusion 9a of the check seal 9 is caught by the step 4g as described above, and the tip of the check seal 9 does not move further to the inner peripheral side, and the warping is repeated. Is prevented and can withstand a large external pressure. The step 4g is provided to prevent the check seal 9 from being bent back, and the shape of the step 4g and the shape of the protrusion 9a are not particularly limited, but both may be easily engaged with each other. desirable. Therefore, in this case, since the cross section of the protrusion 9a is circular, the step 4g is also provided with a curved surface so that it can be easily engaged with the protrusion 9a.

  As can be understood from the above description, in the check seal 9 in which the check seal structure of the present invention is embodied, the pressure receiving area is sufficiently secured, so that not only the valve can be opened reliably with a small internal pressure, but also the valve opening and closing operations. Therefore, the check seal 9 is not subjected to vibrational stress, and the deterioration of the check seal 9 is not promoted.

  In addition, since the valve opening operation and the valve closing operation of the check seal 9 are oscillated repeatedly, there is no inconvenience that the fluctuation of the internal pressure in the space A becomes severe. Therefore, the sliding resistance of the rod 3 is stabilized and the stable and smooth expansion and contraction operation of the hydraulic shock absorber can be compensated.

  Further, in this check seal structure, the design seal 9 can be freely designed in combination with the fact that the engagement between the protrusion 9a of the check seal 9 and the step 4g can withstand a large external pressure and the valve can be reliably opened with a small internal pressure. As a result, the versatility of the check seal 9 is improved.

  Further, in the case of this embodiment, the inner peripheral side surface s of the seat portion 4f of the rod guide 4 is set along the inclination of the check seal 9, so that an external pressure that is an abnormally high pressure acts from the reservoir R side. However, the force acting on the check seal 9 is such that the entire check seal 9 is pressed against the inner peripheral side surface s which is the opposite surface of the seat portion 4f, and the check seal 9 comes into close contact with the seat portion 4f and the reservoir R As a result, it is possible to reliably prevent the backflow of gas and hydraulic oil from the space A to the space A, and the setting itself prevents the check seal 9 from warping, and furthermore, stress is applied to the root portion 9b and the intermediate portion of the check seal 9. Since the concentrated bending point is not generated, the life of the check seal 9 can be further extended.

  In addition, in the place mentioned above, although the check seal | sticker 9 becomes a shape inclined so that it may expand toward a lower end outer peripheral side with respect to the axis line of the rod 3 which becomes an up-down direction in FIG. 1, this is shown in FIG. As shown in the figure, a bowl shape may be used. When the check seal 9 has a bowl shape as described above, the rigidity of the check seal 9 is reduced, so that the valve opening pressure can be further reduced. Further, in this case, there is no need to form a seat portion with an inclined surface formed by projecting the inner peripheral side of the step portion 4e of the rod guide 4 upward in the figure, and the horizontal step portion 4e itself in FIG. , The check seal facing surface t of the stepped portion 4e can be along the check seal 9, which is advantageous in terms of processing.

  Further, as shown in FIG. 4, the check seal 9 may be cylindrical, and in this case, since the rigidity of the check seal 9 is increased, the valve opening pressure can be increased. In this case, if the sheet portion 11 is formed on the outer periphery of the cylindrical portion 10 provided on the inner peripheral side of the step portion 4 e of the rod guide 4, the check seal facing surface u in the sheet portion 11 is along the check seal 9. Can be set as follows.

  As described above, the bending rigidity can be adjusted by the shape of the check seal 9, and the valve opening pressure in the check seal 9 can be tuned.

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

It is a longitudinal cross-sectional view of the head part of the hydraulic shock absorber with which the check seal structure in one embodiment was embodied. It is an expanded vertical sectional view of the head part of the hydraulic shock absorber with which the check seal structure in one embodiment was embodied. It is an expansion longitudinal cross-sectional view of the head part of the hydraulic shock absorber with which the check seal | sticker structure in one modification of one Embodiment was actualized. It is an expanded vertical sectional view of the head part of the hydraulic shock absorber with which the check seal structure in other modifications of one embodiment was embodied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Outer cylinder 3 Rod 4 Rod guide 4a Convex part 4b in the rod guide Concave part 4c in the rod guide Notch 4d in the rod guide 4d Communication hole 4e in the rod guide Step part 4f in the rod guide 11 Seat part 4g in the rod guide In the rod guide Step 5 Insert metal 6 Slide bearing 7 Inner seal 7a Dustrip 7b Oil lip 8 Outer seal 9 Check seal 9a Protrusion 9b at the tip of the check seal 10 Base part of the check seal A Space R Reservoir R1 Rod side chamber s Inner side surface t, u of the seat part that is the opposing surface of the rod guide The check seal opposing surface of the rod guide

Claims (2)

A rod guide that supports a rod that is inserted into the cylinder so as to be movable while closing the opening end of the cylinder and the opening of the outer cylinder that covers the cylinder in the hydraulic shock absorber; and an annular insert metal that is stacked on the rod guide An annular check seal that is provided on the insert metal and that abuts against the rod guide and allows only the flow of hydraulic oil from the space between the rod guide and the insert metal toward the reservoir formed between the cylinder and the outer cylinder. In the check seal structure provided, a protrusion that abuts the rod guide is provided at the tip of the check seal, and a step is provided on the rod guide that engages the protrusion to restrict the check seal from curving toward the inner periphery. The pressure-receiving surface on the valve opening side of the seal is connected to the insert metal from the contact portion of the protrusion with the rod guide. Molding so as to range up to the root portion and the opposing surface of the rod guide serving as a seat portion facing the inner circumferential surface of the check seal along the slope of the check seal in a state where the projection is in contact with the rod guide Check seal structure characterized by being set. 2. The check seal structure according to claim 1, wherein the check seal is formed so as to be inclined while expanding the diameter toward the outer peripheral side of the lower end with respect to the axis of the rod inserted in the vertical direction.

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