JPWO2018097119A1 - Dust seal - Google Patents

Abstract

Provided is a dust seal capable of suppressing a decrease in function of a metal pressing member. In the dust seal 100 that seals the annular gap between the shaft 500 and the housing 600, an elastic seal body 120 having a dust strip 123 that is in close contact with the shaft 500, and embedded in the seal body 120, the dust strip 123 is provided. And a metal pressing member 130 that presses inward in the radial direction.

Description

  The present invention relates to a dust seal that seals an annular gap between a shaft and a housing.

  In various devices such as a hydraulic cylinder, a dust seal is provided in order to suppress entry of foreign matter from the outside into the device. The seal body in the dust seal is made of an elastic body such as polyurethane elastomer or rubber. In the case of a single elastic body, the sealing performance deteriorates due to the occurrence of settling (plastic deformation) after long-term use. Therefore, a technique is known in which a pressing member (metal spring) is provided for pressing the dust lip provided in the seal body toward the inside in the radial direction (see Patent Document 1).

  However, in such a technique, there is a possibility that the pressing function may not be exhibited due to dust (such as muddy water) adhering to the pressing member and solidifying. Moreover, the salt content and metal powder contained in the dust may cause rust and electric corrosion to occur on the metal pressing member, thereby reducing the function.

Japanese Utility Model Publication No. 63-27763

  The objective of this invention is providing the dust seal which can aim at suppression of the fall of the function of a metal press member.

  The present invention employs the following means in order to solve the above problems.

That is, the dust seal of the present invention is
In the dust seal that seals the annular gap between the shaft and the housing,
A seal body made of an elastic body having a dust lip closely contacting the shaft;
A metal pressing member that is embedded inside the seal body and presses the duster strip radially inward;
It is characterized by providing.

  According to the present invention, since the metal pressing member is embedded in the seal body, dust (foreign matter) does not adhere to the pressing member.

The dust lip is provided so as to extend from the sealing region side to the side opposite to the sealing region and radially inward,
The pressing member has a pressing portion that extends from the sealing region side to the opposite side of the sealing region and radially inward within the dust lip and presses the dustlip radially inward. .

  In this manner, the dust lip can be pressed radially inward by the pressing portion provided on the pressing member.

A reinforcing ring having an annular portion and an inward flange portion provided at an end of the annular portion;
The seal body provided integrally with the reinforcing ring;
With
The pressing member may include an annular portion provided along the inner side of the annular portion and an inward flange portion provided along the inward flange portion.

  Thereby, even when the seal body is integrally formed with the reinforcing ring, the positioning accuracy of the pressing member with respect to the reinforcing ring can be increased.

  The seal body is provided with a recess for positioning the pressing member with respect to the reinforcement ring by a molding die that integrally forms the seal body with respect to the reinforcement ring on the radially inner side of the annular portion. It is good to have.

  Thereby, even when the seal body is integrally formed with the reinforcing ring, the positioning accuracy of the pressing member with respect to the reinforcing ring can be further increased.

  The pressing member may be provided with a plurality of through portions penetrating the front and back.

  Accordingly, when the seal body is integrally formed with the reinforcing ring, the flow resistance of the molding material against the pressing member can be suppressed when the molding material for molding the seal body flows during molding. . Thereby, the positioning accuracy of the pressing member with respect to the reinforcing ring can be further increased.

  In addition, said each structure can be employ | adopted combining as much as possible.

  As described above, according to the present invention, it is possible to suppress the deterioration of the function of the metal pressing member.

FIG. 1 is a schematic cross-sectional view of a dust seal according to Embodiment 1 of the present invention. FIG. 2 is a schematic cross-sectional view of a sealing structure to which the dust seal according to the first embodiment of the present invention is applied. FIG. 3 is a part of a perspective view of a pressing member provided in the dust seal according to the first embodiment of the present invention. FIG. 4 is a partially broken perspective view of the dust seal according to the first embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a sealing structure to which a dust seal according to Example 2 of the present invention is applied. FIG. 6 is a part of a perspective view of a pressing member provided in a dust seal according to Embodiment 2 of the present invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail 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. .

(Example 1)
With reference to FIGS. 1-4, the dust seal which concerns on Example 1 of this invention is demonstrated. The dust seal according to the embodiment of the present invention can be used for a hydraulic cylinder provided in a construction machine, an automobile shock absorber, a damper, a general industrial device, and the like. In addition, the sealing structure to which the dust seal according to the present embodiment is applied includes a shaft, a housing, and a dust seal that seals an annular gap between the shaft and the housing. The dust seal is preferably used when the shaft and the housing move relative to each other. The relative movement between the shaft and the housing includes the case where the two or more movements are performed in combination when the reciprocating movement is relatively relative, the relative rotation is performed, or the relative swinging is performed. It is.

  FIG. 1 is a schematic cross-sectional view of a dust seal according to Embodiment 1 of the present invention. The dust seal according to the present embodiment has a rotationally symmetric shape except for a part of the configuration, and FIG. 1 shows a cross-sectional view of the dust seal taken along a plane including the central axis of the dust seal. FIG. 2 is a schematic cross-sectional view of a sealing structure to which the dust seal according to the first embodiment of the present invention is applied. 2 also shows a cross-sectional view of the dust seal or the like cut along a plane including the center axis of the dust seal. FIG. 3 is a part of a perspective view of a pressing member provided in the dust seal according to the first embodiment of the present invention. FIG. 4 is a partially broken perspective view of the dust seal according to the first embodiment of the present invention, and shows a part of a perspective view of the dust seal cut along a plane including the central axis.

<Sealing structure>
With reference to FIG. 2, the sealing structure to which the dust seal according to the present embodiment is applied will be described. The sealing structure according to the present embodiment includes a housing 600 having a shaft hole, a shaft 500 inserted through the shaft hole, and a dust seal 100. An annular gap between the shaft 500 and the housing 600 is sealed by the dust seal 100. In FIG. 2, the left side is a sealed region side (O) in which a fluid to be sealed (for example, oil) is sealed, and the right side is a side opposite to the sealed region (atmosphere side (A)).

<Dust seal>
With reference to FIGS. 1-4, the dust seal 100 which concerns on a present Example is demonstrated in detail. The dust seal 100 according to the present embodiment includes a metal reinforcing ring 110, an elastic seal body 120 provided integrally with the reinforcing ring 110, and a metal ring embedded in the seal body 120. The pressing member (spring) 130 is provided. Note that the dust seal 100 can be obtained by molding the seal body 120 by insert molding (injection molding) using the reinforcing ring 110 and the pressing member 130 as insert parts. The seal body 120 is made of polyurethane elastomer or rubber.

  The reinforcing ring 110 includes an annular portion 111 and an inward flange portion 112 provided at the end of the annular portion 111. The annular portion 111 according to the present embodiment has a cylindrical shape. The annular seal 111 is fitted to the inner peripheral surface of the shaft hole of the housing 600, whereby the dust seal 100 is fixed to the housing 600.

  The seal body 120 includes an annular portion 121, a main lip 122, and a dust lip 123. The annular portion 121 is provided on the inner peripheral surface side of the annular portion 111 in the reinforcing ring 110. The main lip 122 extends from the atmosphere side (A) to the sealed region side (O) and radially inward, and is configured to be in close contact with the shaft 500. The dust lip 123 is provided on the atmosphere side (A) with respect to the main lip 122, and extends from the sealing region side (O) to the atmosphere side (A) and radially inward, so as to be in close contact with the shaft 500. Has been. When the shaft 500 and the housing 600 move relative to each other, the tip end of the main lip 122 and the tip end of the dust lip 123 slide while maintaining a state in close contact with the outer peripheral surface of the shaft 500.

  The pressing member 130 includes a first annular portion 131 provided along the inside of the annular portion 111 in the reinforcing ring 110, an inward flange portion 132 provided along the inward flange portion 112 in the reinforcing ring 110, and an inward flange. And a second annular portion 133 provided along the tip of the portion 112. The pressing member 130 has a pressing portion 134 that extends from the tip of the second annular portion 133 toward the atmosphere side (A) and radially inward, and presses the dust lip 123 radially inward.

  Further, a concave portion 121 a is provided on the inner peripheral surface side of the annular portion 121 in the seal body 120 on the radially inner side of the first annular portion 131 in the pressing member 130. In addition, the recessed part 121a is provided with two or more at intervals in the circumferential direction. These recesses 121 a are provided for positioning the pressing member 130 with respect to the reinforcing ring 110 by a molding die that integrally molds the seal body 120 with respect to the reinforcing ring 110. This point will be described with reference to FIG. 4 is a part of a sectional view when the reinforcing ring 110 and the pressing member 130 are set with respect to the molding die 700 (the end of the annular portion 111 and the pressing member 130 in the reinforcing ring 110). The vicinity of the end of the first annular portion 131 in FIG. For the molding die 700, the reinforcing ring 110 and the pressing member 130 are set in a state in which they are overlapped. At this time, the annular portion 111 of the reinforcing ring 110 and the first annular portion 131 of the pressing member 130, the inward flange portion 112 of the reinforcing ring 110 and the inward flange portion 132 of the pressing member 130, and the inward flange portion 112 of the reinforcing ring 110. And the second annular portion 133 of the pressing member 130 are in close contact with each other. The pressing member 701 provided in the molding die 700 keeps the pressing member 130 positioned with respect to the reinforcing ring 110 even during molding.

  In FIG. 4, C indicates a cavity. A portion of the cavity C shown in a circle in FIG. 4 corresponds to a portion where the annular portion 121 in the seal body 120 is formed. And the recessed part 121a is formed of the site | part corresponded to the pressing part 701. FIG. In a state where the reinforcing ring 110 and the pressing member 130 are set with respect to the molding die 700, the pressing portion 701 in the molding die 700 is in contact with a part of the first annular portion 131 in the pressing member 130. Yes. Thereby, the state in which the reinforcing ring 110 and the pressing member 130 are positioned in the molding die 700 is maintained.

  In addition, the pressing member 130 is provided with a plurality of through portions 135 penetrating the front and back. In the present embodiment, the penetrating portion 135 is configured by a slit that extends in parallel with the central axis from the end portion on the pressing portion 134 side of the pressing member 130 to the vicinity of the end portion on the first annular portion 131 side. As described above, by providing the plurality of through portions 135, the material of the seal body 120 can pass through the through portions 135 when insert molding is performed.

<Excellent point of dust seal according to the present embodiment>
According to the dust seal 100 according to the present embodiment, since the metal pressing member 130 is embedded in the seal body 120, dust (foreign matter) does not adhere to the pressing member 130 (at least the pressing portion 134). Absent. Therefore, there is no possibility that dust (such as muddy water) adheres to the pressing member 130 and the pressing function is not exhibited. Further, the salt or metal powder contained in the dust does not cause rust or electric corrosion on the pressing member 130 to deteriorate the function. As described above, it is possible to suppress the deterioration of the function of the metal pressing member 130.

  Further, the pressing member 130 according to the present embodiment includes a first annular portion 131 provided along the inside of the annular portion 111 in the reinforcing ring 110 and an inward flange provided along the inward flange portion 112 in the reinforcing ring 110. It has a portion 132. Thereby, even when the seal body 120 is integrally formed with the reinforcing ring 110, the positioning accuracy of the pressing member 130 with respect to the reinforcing ring 110 can be increased.

  Further, the seal body 120 is pressed against the reinforcing ring 110 by a molding die 700 that integrally molds the seal body 120 with respect to the reinforcing ring 110 inside the annular portion 131 of the pressing member 130 in the radial direction. A recess 121a for positioning is provided. Thereby, even when the seal body 120 is integrally formed with the reinforcing ring 110, the positioning accuracy of the pressing member 130 with respect to the reinforcing ring 110 can be further enhanced. Note that the pressing member 130 may be exposed in the portion where the recess 121a is provided. However, even if dust adheres to the part, the pressing function by the pressing member 130 is hardly affected.

  Further, the pressing member 130 is provided with a plurality of through portions 135 penetrating the front and back. Thereby, when the seal body 120 is integrally molded with the reinforcing ring 110, the flow resistance of the molding material against the pressing member 130 is suppressed when the molding material for molding the seal body 120 flows during molding. Can be made. Thereby, the positioning accuracy of the pressing member 130 with respect to the reinforcing ring 110 can be further enhanced.

(Example 2)
5 and 6 show a second embodiment of the present invention. The sealing structure and application to which the dust seal 200 according to the present embodiment is applied are the same as in the first embodiment. FIG. 5 is a schematic cross-sectional view of a sealing structure to which a dust seal according to Example 2 of the present invention is applied. The dust seal according to the present embodiment also has a rotationally symmetric shape except for a part of the configuration, and FIG. 5 shows a cross-sectional view of the dust seal cut along a plane including the central axis of the dust seal. FIG. 6 is a part of a perspective view of a pressing member provided in a dust seal according to Embodiment 2 of the present invention.

<Sealing structure>
With reference to FIG. 5, the sealing structure to which the dust seal based on a present Example is applied is demonstrated. The sealing structure according to the present embodiment includes a housing 600 having a shaft hole, a shaft 500 inserted through the shaft hole, and a dust seal 200. An annular gap between the shaft 500 and the housing 600 is sealed by the dust seal 200. In FIG. 5, the left side is a sealed region side (O) in which a fluid to be sealed (for example, oil) is sealed, and the right side is a side opposite to the sealed region (atmosphere side (A)).

<Dust seal>
With reference to FIG.5 and FIG.6, the dust seal 200 which concerns on a present Example is demonstrated in detail. The dust seal 200 according to the present embodiment includes a metal reinforcing ring 210, an elastic seal body 220 provided integrally with the reinforcing ring 210, and a metal ring embedded in the seal body 220. The pressing member (spring) 230 is provided. The dust seal 200 is obtained by molding the seal body 220 by insert molding (injection molding) using the reinforcing ring 210 and the pressing member 230 as insert parts. The seal body 220 is made of polyurethane elastomer or rubber.

  The reinforcing ring 210 includes an annular portion 211 and an inward flange portion 212 provided at the end of the annular portion 211. The annular portion 211 according to the present embodiment has a cylindrical shape. The dust seal 200 is fixed to the housing 600 by fitting the annular portion 211 to the inner peripheral surface of the shaft hole of the housing 600.

  The seal body 220 includes an annular portion 221 and a dust lip 222. The annular portion 221 is provided on the inner peripheral surface side of the annular portion 211 in the reinforcing ring 210. The dust lip 222 extends from the sealed region side (O) to the atmosphere side (A) and radially inward, and is configured to be in close contact with the shaft 500. When the shaft 500 and the housing 600 move relative to each other, the dust lip 222 slides while maintaining the state where the tip of the dust lip 222 is in close contact with the outer peripheral surface of the shaft 500.

  The pressing member 230 has an annular portion 231 provided along the inside of the annular portion 211 in the reinforcing ring 210 and an inward flange portion 232 provided along the inward flange portion 212 in the reinforcing ring 210. The pressing member 230 has a pressing portion 233 that extends from the tip of the inward flange portion 232 toward the atmosphere side (A) and radially inward, and presses the dust lip 222 radially inward.

  Further, on the inner peripheral surface side of the annular portion 221 in the seal body 220, a recess 221a is provided on the radially inner side of the annular portion 231 of the pressing member 230. In addition, the recessed part 221a is provided with two or more at intervals in the circumferential direction. These recesses 221 a are provided for positioning the pressing member 230 with respect to the reinforcing ring 210 by a molding die for integrally molding the seal body 220 with respect to the reinforcing ring 210. This point is as described in the first embodiment.

  Also in the pressing member 230 according to the present embodiment, a plurality of through portions 234 penetrating the front and back are provided. In the present embodiment, the penetrating portion 234 is constituted by a slit that extends in parallel to the central axis from the end portion on the pressing portion 233 side of the pressing member 230 and extends to the vicinity of the end portion on the annular portion 231 side. Thus, by providing the plurality of through portions 234, the material of the seal body 220 can pass through the through portions 234 when insert molding is performed.

  Also in the dust seal 200 according to the present embodiment configured as described above, the same effects as those of the first embodiment can be obtained.

(Other)
In each of the above embodiments, the case of a dust seal provided with a reinforcing ring has been described as an example. However, the present invention is also applicable to a dust seal not provided with a reinforcing ring. That is, a metal pressing member that presses the dust lip radially inward can be provided inside an elastic seal body that does not include a reinforcing ring. In each of the above embodiments, in order to position the pressing member, the pressing member is positioned with respect to the reinforcing ring (the pressing member has a shape portion along the reinforcing ring, and a recess is provided in the seal body. The configuration has been described as an example. However, in the case where another configuration for positioning the pressing member inside the seal body of the dust seal can be employed, the above configuration may not be employed.

100, 200 Dust seal 110, 210 Reinforcement ring 111, 211 Annular part 112, 212 Inward flange part 120, 220 Seal body 121, 221 Annular part 121a, 221a Recessed part 122 Main lip 123, 222 Dustrip 130, 230 Press member 131 1st 1 annular portion 231 annular portion 132,232 inward flange portion 133 second annular portion 134,233 pressing portion 135,234 penetrating portion 500 shaft 600 housing 700 molding die 701 holding portion C cavity

That is, the dust seal of the present invention is
In the dust seal that seals the annular gap between the shaft and the housing,
A seal body made of an elastic body having a dust lip closely contacting the shaft;
A metal pressing member that is embedded inside the seal body and presses the duster strip radially inward;
A dust seal comprising:
A reinforcing ring having an annular portion and an inward flange portion provided at an end of the annular portion;
The seal body provided integrally with the reinforcing ring;
With
The pressing member has an annular portion provided along the inner side of the annular portion, and an inward flange portion provided along the inward flange portion.
The seal body is provided with a recess for positioning the pressing member with respect to the reinforcement ring by a molding die that integrally forms the seal body with respect to the reinforcement ring on the radially inner side of the annular portion. It is characterized by.

According to the present invention, since the metal pressing member is embedded in the seal body, dust (foreign matter) does not adhere to the pressing member. Even when the seal body is integrally formed with the reinforcing ring, the positioning accuracy of the pressing member with respect to the reinforcing ring can be increased.

Claims (5)

In the dust seal that seals the annular gap between the shaft and the housing,
A seal body made of an elastic body having a dust lip closely contacting the shaft;
A metal pressing member that is embedded inside the seal body and presses the duster strip radially inward;
A dust seal characterized by comprising: The dust lip is provided so as to extend from the sealing region side to the side opposite to the sealing region and radially inward,
The pressing member has a pressing portion that extends from the sealing region side to the opposite side of the sealing region and radially inward within the dust lip and presses the dustlip radially inward. The dust seal according to claim 1. A reinforcing ring having an annular portion and an inward flange portion provided at an end of the annular portion;
The seal body provided integrally with the reinforcing ring;
With
3. The dust seal according to claim 1, wherein the pressing member includes an annular portion provided along an inner side of the annular portion and an inward flange portion provided along the inward flange portion.   The seal body is provided with a recess for positioning the pressing member with respect to the reinforcement ring by a molding die that integrally forms the seal body with respect to the reinforcement ring on the radially inner side of the annular portion. The dust seal according to claim 3, wherein the dust seal is provided.   The dust seal according to any one of claims 1 to 4, wherein the pressing member is provided with a plurality of through portions penetrating the front and back.

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