JP2008045658A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device which keeps an appropriate oil pressure for a long time with respect to a reciprocating motion. <P>SOLUTION: The sealing device 1 is mounted in an annular groove 41 provided in any one of a housing 30 having a shaft bore therein and a shaft 40 to be inserted into the shaft bore, and seals the annular clearance 5 between the two members. The sealing device 1 comprises: a resinoid ring 10 to be brought into sliding contact with the housing 30; and a rubber ring 20 which is arranged between the resinoid ring 10 and the annular groove 41, and energizes the resinoid ring 10 toward the housing 30. The resinoid ring 10 has its height equal to the width of the annular groove 41, and has slits 13 formed on its side surfaces 12, and has a recessed portion 14 formed on its contact surface with the rubber ring 20. The rubber ring 20 has a projecting portion 23 to be fitted into the recessed portion 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sealing device used for a hydraulic cylinder or the like.

  As a sealing device used for a hydraulic cylinder, there is one as shown in FIG. The sealing device 100 is used as a sealing device for the piston 201 of the hydraulic cylinder 200 and used for the outer peripheral sliding portion D of the hydraulic cylinder 200, and is provided to hold the hydraulic pressure in the reciprocating motion of the rod 202. .

  As shown in FIG. 7, the sealing device 100 includes a resin ring 101 and a rubber ring 102, and is attached to an annular groove 203 formed on the outer peripheral surface of the piston 201.

  The resin ring 101 is an annular member having a substantially rectangular cross section made of a resin material such as ethylene tetrafluoride (PTFE), its outer peripheral surface 111 is in sliding contact with the inner peripheral surface of the hydraulic cylinder 200, and its side surface 121 is an annular groove 203. It adheres closely to the side surface 204 of the.

  The rubber ring 102 is compressed and mounted between the resin ring 101 and the groove bottom of the annular groove 203, and the resin ring 101 is urged toward the hydraulic cylinder 200 by its elastic restoring force, so that the resin ring 101 and the hydraulic cylinder 200 are urged. To improve the adhesion between the two.

There are some related techniques described in the following documents.
Utility Model Registration No. 2538325 JP-A-9-133216 JP 2003-254437 A

  As shown in FIG. 7A, the resin ring 101 and the rubber ring 102 are side surfaces on the other axial side (lower side) of the annular groove 203 by the hydraulic pressure P applied from one side (upper side) in the axial direction. 204 is pressed against. When the direction in which the hydraulic pressure is applied by the reciprocating movement of the rod 202 is changed, the resin ring 101 and the rubber ring 102 are respectively in the axial direction one side (upward in the figure) of the annular groove 203 by the hydraulic pressure P applied from the other side in the axial direction (lower in the figure). As shown in FIG. 7B, the ring groove 203 is pressed against the side surface 204 on one axial side (the upper side in the figure) of the annular groove 203.

  In the sealing device for the piston of the hydraulic cylinder, such a change in the hydraulic direction occurs repeatedly, so that the rubber ring 102 slides on the inner peripheral surface of the resin ring 101 every time the hydraulic direction is changed, and the axial direction. It will go back and forth between one side and the other.

  Then, the rubber ring 102 is worn on the contact surface with the resin ring 101 (E in FIG. 7). As a result, the crushing margin of the rubber ring 102 is reduced and the resin ring 101 and the hydraulic cylinder 200 are in close contact with each other. There was a problem that the performance would be lowered.

  Further, as shown in FIG. 8, when the hydraulic direction is switched and the resin ring 101 moves in the annular groove 203, a part of the resin ring 101 is between the rubber ring 102 and the side surface 204 of the annular groove 203. There was also a problem of being caught in the gap (FIG. 8B). In such a state, the hydraulic pressure cannot be properly maintained.

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a sealing device capable of maintaining an appropriate hydraulic pressure for a long period of time against reciprocation.

In order to achieve the above object, a sealing device according to the present invention comprises:
A sealing device that is attached to an annular groove provided in one member of a housing having a shaft hole and a shaft inserted into the shaft hole, and seals an annular gap between the two members,
A resin ring in sliding contact with the other member;
A rubber ring that is mounted between the resin ring and the annular groove and biases the resin ring toward the other member;
With
The resin ring has a height that matches the width of the annular groove, a slit is formed on the side surface, and a recess is formed on the contact surface with the rubber ring,
The rubber ring includes a convex portion fitted into the concave portion.

  Since the height of the resin ring matches the width of the annular groove, the resin ring is restrained from moving in the annular groove when the hydraulic direction is switched, and a part of the resin ring is separated from the rubber ring and the annular groove. It is prevented from being caught in the gap between the two.

  Further, by providing the slit, the annular groove is not completely blocked by the resin ring, and hydraulic pressure can be introduced into the annular groove.

  In addition, since the resin ring and the rubber ring are in contact with each other by concave-convex fitting, the rubber ring is prevented from sliding with respect to the resin ring when the hydraulic direction is switched, and the contact surface of the rubber ring with the resin ring Wear can be suppressed.

  Here, the height of the resin ring refers to the axial width, and the side surface of the resin ring refers to the end surface in the axial direction.

The concave portion is composed of a tapered surface portion formed on each end in the axial direction, and a peripheral surface portion parallel to the axis formed between the tapered surface portions,
The convex portion may include a tapered surface portion and a peripheral surface portion corresponding to the shapes of the tapered surface portion and the peripheral surface portion of the concave portion.

  Each circumferential surface portion of the concave portion and the convex portion may have an axial width of at least 1 mm.

  As described above, according to the present invention, it is possible to maintain an appropriate hydraulic pressure for a long time against reciprocation.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

First, with reference to FIG. 4, a schematic configuration of a sealing device according to an embodiment of the present invention will be described.
FIG. 4 is a schematic cross-sectional view showing a mounting state of the sealing device according to the present embodiment.

<Configuration and outline of sealing device>
A sealing device 1 according to the present embodiment is a sealing device for a piston in a hydraulic cylinder as shown in FIG. 6 and is provided to hold the hydraulic pressure in the reciprocating motion of a rod. The sealing device 1 includes a resin ring 10 and a rubber ring 20, and an annular gap 5 between a housing (cylinder) 30 having a shaft hole and a shaft (piston and rod) 40 inserted into the shaft hole. To seal.

  The sealing device 1 is mounted in an annular groove 41 provided on the outer peripheral surface of the shaft 40. The resin ring 10 is disposed on the opening side of the annular groove 41, the outer peripheral surface 11 is in sliding contact with the inner peripheral surface of the housing 30, and the side surface 12 is in close contact with the side surface 42 of the annular groove 41. The rubber ring 20 is mounted by being compressed between the resin ring 10 and the groove bottom 43 of the annular groove 41, the outer peripheral surface thereof is in close contact with the inner peripheral surface of the resin ring 10, and the inner peripheral surface 21 thereof is the annular groove 41. In close contact with the groove bottom 43. The rubber ring 20 urges the resin ring 10 toward the housing 30 by its elastic restoring force, thereby improving the adhesion between the resin ring 10 and the housing 30.

  A gap 6 is formed between the side surface 22 of the rubber ring 20 and the side surface 42 of the annular groove 41. A plurality of slits 13 for introducing hydraulic pressure are formed on the side surface 12 of the resin ring 10, and the gap 6 and the annular gap 5 are communicated with each other through the slit 13.

  An annular recess 14 extending in the circumferential direction is formed on the inner peripheral surface of the resin ring 10. On the other hand, an annular protrusion 23 extending in the circumferential direction is formed on the outer peripheral surface of the rubber ring 20. The resin ring 10 and the rubber ring 20 are in contact with each other with the concave portion 14 and the convex portion 23 fitted.

  Next, with reference to FIGS. 1-3, schematic structure of the resin ring 10 and the rubber ring 20 which comprise the sealing device 1 which concerns on a present Example is demonstrated. 1A and 1B are schematic views showing a configuration of a resin ring of a sealing device according to the present embodiment, in which FIG. 1A shows a state seen from an axial direction, and FIG. 1B is a cross-sectional view taken along line AA in FIG. 2A and 2B are schematic views showing the configuration of the rubber ring of the sealing device according to the present embodiment, in which FIG. 2A shows a state seen from the axial direction, and FIG. 2B is a BB cross-sectional view of FIG. FIG. 3 is a schematic cross-sectional view showing a dimensional relationship among the resin ring, the rubber ring, and the annular groove of the sealing device according to the present embodiment.

<Configuration and overview of resin ring>
As shown in FIG. 1, the resin ring 10 is an annular member having a substantially rectangular cross section, and is made of a resin material such as ethylene tetrafluoride (PTFE).

  The resin ring 10 has a plurality of slits 13 formed on both side surfaces 12 respectively. The slits 13 are formed at equal intervals on both side surfaces 12, and the circumferential arrangement is staggered between the slits 13 formed on one side surface 12 and the slits 13 formed on the other side surface 12. It is formed as follows.

  In addition, the inner peripheral surface of the resin ring 10 is formed with tapered surface portions 14a that are inclined in the outer diameter direction from the end portion in the axial direction toward the center on both sides of the inner peripheral surface. Further, a peripheral surface portion 14b extending in parallel with the axial direction is formed between the tapered surface portions 14a. The tapered surface portion 14a and the peripheral surface portion 14b constitute an annular concave portion 14 extending in the circumferential direction on the inner peripheral surface of the resin ring 10.

<Configuration and overview of rubber ring>
As shown in FIG. 2, the rubber ring 20 is an annular member having a substantially rectangular cross section, and is made of a rubber material such as nitrile rubber.

  On the outer peripheral surface of the rubber ring 20, tapered surface portions 23a that are inclined in the outer diameter direction from the end portion in the axial direction toward the center are formed on both sides of the outer peripheral surface. Further, a peripheral surface portion 23b extending in parallel with the axial direction is formed between the tapered surface portions 23a. The tapered surface portion 23a and the peripheral surface portion 23b constitute an annular convex portion 23 that extends in the circumferential direction on the outer peripheral surface of the rubber ring 20.

<Dimensional relationship among resin ring, rubber ring and annular groove>
As shown in FIG. 3, the height of the resin ring 10 (the width in the axial direction) and the width of the annular groove 41 are set to the same dimension W1. Moreover, the peripheral surface part 14b of the recessed part 14 of the resin ring 10 and the peripheral surface part 23b of the convex part 23 of the rubber ring 20 are set to the same width W2.

  Further, the tapered surface portion 14a of the concave portion 14 of the resin ring 10 and the tapered surface portion 23a of the convex portion 23 of the rubber ring 20 are set to the same inclination angle. That is, the concave portion 14 of the resin ring 10 and the convex portion 23 of the rubber ring 20 are formed in shapes corresponding to each other, and in the mounted state, the tapered surface portion 14a and the tapered surface portion 23a, and the peripheral surface portion 14b and the peripheral surface portion 23b. And abut each other.

  Here, the width W2 of the peripheral surface portions 14b and 23b is set to 1 mm or more in order to prevent the resin ring 10 from being damaged by stress concentration on the tapered surface portion 14a of the resin ring 10 during hydraulic action. preferable.

  Next, with reference to FIG. 5, the state at the time of use of the sealing device 1 which concerns on a present Example is demonstrated. FIG. 5 is a schematic cross-sectional view showing a state where hydraulic pressure acts in the sealing device according to the present embodiment, (a) shows a case where the hydraulic pressure acts from one side in the axial direction (upward in the figure), (B) shows the case where the hydraulic pressure acts from the other side in the axial direction (downward in the figure).

<Hydraulic action>
As shown in FIG. 5A, when the hydraulic pressure is applied from one side in the axial direction (the upper side in the figure), through the slit 13 for introducing the hydraulic pressure provided on the side surface 12 on the one side in the axial direction of the resin ring 10, Hydraulic pressure is introduced into the gap 6 on one axial side between the side surface 22 of the rubber ring 20 and the annular groove 41.

  With this hydraulic pressure, the rubber ring 20 is pushed toward the other side in the axial direction (downward in the figure). On the other hand, since the height of the resin ring 10 coincides with the width of the annular groove 41, the resin ring 10 is restricted from moving in the annular groove 41 with respect to the hydraulic pressure.

  At this time, since the convex part 23 formed on the outer peripheral surface of the rubber ring 20 is fitted into the concave part 14 formed on the inner peripheral surface of the resin ring 10, the outer peripheral surface of the rubber ring 20 is the inner side of the resin ring 10. Sliding against the peripheral surface is suppressed.

  Therefore, the rubber ring 20 maintains the contact state between the peripheral surface portion 23b of the convex portion 23 and the peripheral surface portion 14b of the concave portion 14 of the resin ring 10, and the outer peripheral surface side is not deformed so much. 41 toward the groove bottom 43 side) of 41 and is greatly deformed to the other side in the axial direction, and is pressed against the side surface 42 on the other axial side of the annular groove 41.

  At this time, since the outer peripheral surface side of the rubber ring 20 is not so deformed by the concave and convex fitting between the convex portion 23 and the concave portion 14, the portion close to the tapered surface portion 23 a of the side surface 22 on the other axial side of the rubber ring 20 is the slit 13. It does not protrude (C in FIG. 5).

  Further, when the rubber ring 20 is pushed to the other side in the axial direction, the tapered surface portion 14a of the concave portion 14 of the resin ring 10 on the other side in the axial direction and the tapered surface portion 23a of the convex portion 23 of the rubber ring 20 in contact therewith. The surface pressure between is increased.

  Next, as shown in FIG. 5 (b), when the direction of the hydraulic pressure is switched by the reciprocating motion of the shaft (piston) 40, and the hydraulic pressure is applied from the other side (downward in the drawing), the shaft of the resin ring 10 The hydraulic pressure is introduced into the gap 6 on the other axial side between the side surface 22 of the rubber ring 20 and the annular groove 41 via the hydraulic pressure introducing slit 13 provided on the side surface 12 on the other side in the direction.

  Due to this hydraulic pressure, the rubber ring 20 is pushed toward one side in the axial direction (upward in the figure), and the height of the resin ring 10 coincides with the width of the annular groove 41. The movement within 41 is restricted.

  Further, the rubber ring 20 has an inner peripheral surface with the concave / convex fitting between the concave portion 14 and the convex portion 23, so that sliding with respect to the resin ring 10 is suppressed and the contact state between the peripheral surface portion 14 b and the peripheral surface portion 23 b is maintained. The side is greatly deformed toward one side in the axial direction and is pressed against the side surface 42 on one side in the axial direction of the annular groove 41.

  Also in this case, as in the case of FIG. 5A described above, a part of the rubber ring 20 does not protrude into the slit 13, and the tapered surface portion 14a on one side in the axial direction of the concave portion 14 of the resin ring 10; The surface pressure between the taper surface portion 23a of the convex portion 23 of the rubber ring 20 in contact with this is increased.

<Excellent point of sealing device according to this embodiment>
According to the sealing device according to the present embodiment, since the height of the resin ring matches the width of the annular groove, the resin ring is prevented from moving in the annular groove when the hydraulic direction is switched, and the resin ring Part of the ring is prevented from being caught in the gap between the rubber ring and the annular groove.

  Further, by providing the slit, the annular groove is not completely blocked by the resin ring, and hydraulic pressure can be introduced into the annular groove.

  In addition, since the resin ring and the rubber ring are in contact with each other by concave-convex fitting, the rubber ring is prevented from sliding with respect to the resin ring when the hydraulic direction is switched, and the contact surface of the rubber ring with the resin ring Wear can be suppressed. Therefore, a reduction in the crushing cost of the rubber ring due to wear is suppressed, and the sealing performance can be maintained for a long period.

  Here, in the sealing device for pistons such as the sealing device according to the present embodiment, in order to exhibit and maintain the sealing performance against high-pressure hydraulic pressure, the sealing device itself is pressed against the other surface by the tightening force. In addition to the close contact, it is important to obtain an expansion force by the hydraulic pressure introduced into the mounting groove (annular groove). However, when the hydraulic pressure is not smoothly introduced into the mounting groove, so-called blow-through leakage (passing) may occur from the hydraulic pressure side to the anti-hydraulic side. Further, as described above, when a part of the resin ring is sandwiched in the gap between the rubber ring and the annular groove, blowout leakage may occur even when the crushing cost of the rubber ring is reduced.

  Therefore, according to the sealing device according to the present embodiment, the occurrence of blow-through leakage can be suppressed.

Further, when the rubber ring is pushed into the side surface of the annular groove by hydraulic pressure, the gap between the taper surface portion of the resin ring concave portion on the side where the rubber ring is pushed in and the taper surface portion of the rubber ring convex portion in contact therewith. Surface pressure is increased. Thereby, the surface pressure with respect to the housing of a resin ring is raised, and adhesiveness and sealing performance are improved.

It is a schematic diagram which shows the structure of the resin ring of the sealing device which concerns on a present Example. It is a schematic diagram which shows the structure of the rubber ring of the sealing device which concerns on a present Example. It is typical sectional drawing which shows the dimensional relationship between the resin ring of the sealing apparatus which concerns on a present Example, a rubber ring, and an annular groove. It is typical sectional drawing which shows the mounting state of the sealing device which concerns on a present Example. It is typical sectional drawing which shows a mode when a hydraulic pressure acts in the sealing apparatus which concerns on a present Example. It is a figure explaining the structure of the hydraulic cylinder in which the sealing device which concerns on a prior art is used. It is typical sectional drawing which shows the use condition of the sealing device which concerns on a prior art. It is typical sectional drawing which shows the use condition of the sealing device which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing device 10 Resin ring 11 Outer peripheral surface 12 Side surface 13 Slit 14 Recessed portion 14a Tapered surface portion 14b Peripheral surface portion 20 Rubber ring 21 Inner peripheral surface 22 Side surface 23 Convex portion 23a Tapered surface portion 23b Peripheral surface portion 30 Housing 40 Shaft 41 Annular groove 42 Side surface 43 Groove Bottom 5 annular gap 6 gap

Claims (3)

A sealing device that is attached to an annular groove provided in one member of a housing having a shaft hole and a shaft inserted into the shaft hole, and seals an annular gap between the two members,
A resin ring in sliding contact with the other member;
A rubber ring that is mounted between the resin ring and the annular groove and biases the resin ring toward the other member;
With
The resin ring has a height that matches the width of the annular groove, a slit is formed on the side surface, and a recess is formed on the contact surface with the rubber ring,
The said rubber ring is provided with the convex part fitted by the said recessed part, The sealing device characterized by the above-mentioned. The concave portion includes a tapered surface portion formed on each of both end sides in the axial direction of the contact surface, and a peripheral surface portion parallel to the axis formed between the tapered surface portions,
The sealing device according to claim 1, wherein the convex portion includes a tapered surface portion and a peripheral surface portion corresponding to shapes of the tapered surface portion and the peripheral surface portion of the concave portion. The sealing device according to claim 2, wherein each of the peripheral portions of the concave portion and the convex portion has an axial width of at least 1 mm.

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