JP2009216168A - Sealing device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device which can be improved in sealing performance and reduced in manufacturing cost. <P>SOLUTION: The sealing device comprises a first seal part having an inner periphery side seal lip 11 and an outer periphery side seal lip 12, an annular recessed portion 15 formed therebetween, and a spring 17 mounted in the annular recessed portion 15 for sealing a first sealed region, and a second seal part having an inner periphery side seal lip 13 and an outer periphery side seal lip 14, an annular recessed portion 16 formed therebetween, and a spring 18 mounted in the annular recessed portion 16 for sealing a second sealed region. contact faces of the seal lips with the other member are molded by a metal mold. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sealing device and a method for manufacturing the sealing device.

  In a fuel pump installed in a gasoline direct injection engine of an automobile, fuel is prevented from flowing from the sliding portion side of the plunger to the cam side, and oil is prevented from entering the plunger sliding portion side from the cam side. Various devices have been conventionally used as sealing devices for that purpose (see each patent document).

  A conventional sealing device for a fuel pump will be described with reference to FIGS. FIG. 6 is a schematic cross-sectional view of a conventional sealing device. FIG. 7 is a schematic cross-sectional view of a conventional sealing device.

  The sealing device 100 shown in FIG. 6 includes a resin seal 101a and a rubber seal 101b as the fuel seal portion 101, and an X ring 102a as the oil seal portion 102, and provides an annular gap between the plunger 200 and the housing 300. Seal.

  Such a type of sealing device 100 requires a spacer 103 between the fuel seal portion 101 and the oil seal portion 102, and is costly because it is composed of a plurality of members. Furthermore, the rubber seal cannot be used because the oil resistance is inferior when the object to be sealed is, for example, gasoline containing a high concentration of alcohol.

  The sealing device 400 shown in FIG. 7 has a configuration in which a resin U packing such as PTFE and a metal spring are combined. Since the fuel pump reciprocates at a high speed with a small stroke length, a resin material such as PTFE with excellent friction characteristics is used as the plunger seal member to prevent wear due to lack of lubrication on the sliding surface. It has been.

  In the sealing device 400, the inner peripheral lip 401 a and the outer peripheral lip 401 b function as the fuel seal portion 401, and the plate-like lip 402 a functions as the oil seal portion 402. In addition, a metal spring 404 is attached to an annular recess 403 formed between the inner peripheral lip 401a and the outer peripheral lip 401b to improve the followability and adhesion of the seal lip made of a resin material to the mating member. .

  However, since such a sealing device forms its shape by cutting, there may be a case where a minute leak from the processing eye occurs, and the manufacturing cost increases because the number of processing steps increases.

Therefore, in recent years, in addition to improving the sealing performance such as pressure resistance and alcohol resistance, it is required to reduce the manufacturing cost.
JP 2003-35239 A JP 2006-34895 A Japanese Utility Model Publication No. 60-131757 Japanese Utility Model Publication No. 61-164862 Japanese Utility Model Publication No. 63-101366 JP-A-4-191571 JP-A-8-82372 Japanese Patent No. 2651407 Japanese Patent No. 2955822 JP 2003-247646 A Patent No. 3971202 Japanese Utility Model Publication No. 62-114272 Japanese Utility Model Publication No. 4-27261

  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 improving the sealing performance and reducing the manufacturing cost. .

In order to achieve the above object, a sealing device according to the present invention comprises:
It is mounted in an annular groove provided in one member of a housing having a relatively reciprocating shaft and a shaft hole into which the shaft is inserted, and from the first sealing region on one axial side to the other axial side. In order to prevent the first sealing fluid from entering the second sealing region and to prevent the second sealing fluid from entering from the second sealing region to the first sealing region, the annular gap between the two members is sealed. A sealing device for
A first seal lip extending toward the first sealing region and contacting the groove bottom surface of the annular groove;
A second seal lip extending toward the first sealing region and slidingly contacting the other member of the two members;
A first annular recess formed between the first seal lip and the second seal lip and opening into a first sealing region;
A first biasing member mounted in the first annular recess, biasing the first seal lip toward the bottom of the annular groove, and biasing the second seal lip toward the other member. ,
A first seal portion having
A third seal lip extending toward the second sealing region and contacting the groove bottom surface of the annular groove;
A fourth seal lip extending toward the second sealing region and slidingly contacting the other member;
A second annular recess formed between the third seal lip and the fourth seal lip and opening to a second sealing region;
A second urging member that is mounted in the second annular recess, urges the third seal lip toward the bottom of the annular groove, and urges the fourth seal lip toward the other member. ,
A second seal part having
The surface where the first seal lip and the third seal lip are in contact with the groove bottom surface of the annular groove, and the surface where the second seal lip and the fourth seal lip are in sliding contact with the other member are gold It is a surface formed by a mold.

  According to this configuration, the seal lip can exhibit high adhesion to any sealed region, and the followability and pressure resistance to the mating member can be improved. Further, the surface where the seal lip comes into contact with the mating member, that is, the seal surface of the seal lip is a mold forming surface, so that the seal surface can be formed without requiring other processes such as cutting. it can.

The first seal lip, the second seal lip, the third seal lip, and the fourth seal lip are urged by annular recesses that are formed on both axial end surfaces of the cylindrical resin molded product and that open in the axial direction. A member is mounted, and the annular recess is preferably formed by being radially expanded by the biasing member.

  Thereby, the process for shaping the shape of the seal lip becomes unnecessary, and the number of manufacturing steps can be reduced.

  The distance between the second seal lip and the fourth seal lip may be longer than the stroke length of the reciprocating movement of the shaft.

  Thereby, the so-called scraping leakage can be prevented. That is, in the relative reciprocal movement of the two members, one sealing fluid adhering to the surface of the other member enters the other sealing region without being scraped off by the sealing lip, thereby leaking into the other sealing region. Is suppressed.

  The shape may be symmetrical in the axial direction.

  As a result, when the sealing device is mounted in the annular groove, it can be assembled in any axial direction, so that no erroneous assembly occurs and the mountability is improved.

  It is good to provide the positioning protrusion pinched | interposed and fixed between the several member which comprises the part of the said annular groove in said one member.

  Thereby, the mounting property of the sealing device to the annular groove is improved, and the sealing device is prevented from dropping from the annular groove when the mating member is assembled.

In order to achieve the above object, a method for manufacturing a sealing device according to the present invention includes:
A manufacturing method of the above-described sealing device,
A step of molding a cylindrical resin molded article having an annular recess recessed in the axial direction along the circumferential direction at both axial end faces;
Cutting the concave portion of the resin molded product into the first annular concave portion and the second annular concave portion; and
Attaching the first biasing member and the second biasing member to the processed first annular recess and the second annular recess;
It is characterized by providing.

  Thus, only the first annular recess and the second annular recess require cutting, and the shape of each seal lip can be manufactured by molding. Therefore, the number of manufacturing processes can be reduced.

  As described above, according to the present invention, it is possible to improve the sealing performance and reduce the manufacturing cost.

  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. .

Example 1
With reference to FIG.1 and FIG.2, the sealing device which concerns on Example 1 of this invention is demonstrated. FIG. 1 is a schematic cross-sectional view of a sealing device according to the present embodiment. FIG. 2 is a schematic half cross-sectional view showing a mounting state of the sealing device according to the present embodiment.

<Configuration and outline of sealing device>
As shown in FIG. 2, the sealing device 1 is an annular seal member made of a resin material such as PTFE, and an annular gap 4 between the housing 2 and the shaft 3 inserted into the shaft hole 20 of the housing 2. Seal. As a specific usage example of the sealing device 1, for example, a plunger seal in a fuel pump provided in a gasoline direct injection engine can be cited. The sealing device 1 is used by being mounted in an annular groove 21 provided on the inner peripheral surface of the shaft hole 20 of the housing 2, and the first sealing region A on one axial side and the second sealing region B on the other axial side. This is a so-called two-component seal that seals between the two.

  As shown in FIG. 1, the sealing device 1 includes a cylindrical seal body 10 having a substantially rectangular cross section, and seal lips 11, 12, 13 extending from the inner and outer peripheral sides of both ends of the seal body 10 in the axial direction. 14, annular recesses 15 and 16 formed between the inner peripheral seal lips 11 and 13 and the outer peripheral seal lips 12 and 14 and opening in the axial direction, and the annular recesses 15 and 16, respectively. Springs 17 and 18.

  Each of the springs 17 and 18 is a metal annular member having a substantially U-shaped or V-shaped half-section, and is configured such that a portion between the inner and outer peripheral sides is recessed in the axial direction with respect to the inner and outer peripheral sides. Yes. The springs 17 and 18 are attached to the annular recesses 15 and 16 so that the recessed portions are on the bottom side of the annular recesses 15 and 16. The annular recesses 15 and 16 are expanded in the radial direction by the springs 17 and 18, and the seal lips 11 to 14 are urged in the radial direction. Thereby, the front end sides of the inner peripheral side seal lips 11 and 13 are inclined in the inner diameter direction, and the front end sides of the outer peripheral side seal lips 12 and 14 are inclined in the outer diameter direction.

  When used as a plunger seal of a fuel pump, for example, an inner peripheral side seal lip 11 and an outer peripheral side seal lip 12 extending toward the first sealing region A side, an annular recess 15 and a spring 17 include a fuel seal portion. (1st seal | sticker part) is comprised. Further, the inner peripheral side seal lip 13 and the outer peripheral side seal lip 14 extending to the second sealing region B side, the annular recess 16 and the spring 18 constitute an oil seal portion (second seal portion).

  That is, the inner peripheral side seal lip 11 is in sliding contact with the outer peripheral surface 30 of the shaft (plunger) 3, and the outer peripheral side seal lip 12 is in close contact with the groove bottom surface 22 of the annular groove 21 of the housing (cylinder, cylinder holder, etc.) 2. This prevents fuel such as gasoline from entering the second sealed area B from the first sealed area A. Further, when the inner peripheral side seal lip 13 is in sliding contact with the outer peripheral surface 30 of the shaft 3 and the outer peripheral side seal lip 14 is in close contact with the groove bottom surface 22 of the annular groove 21, oil such as engine oil is supplied to the second sealing region. Intrusion from B into the first sealed area A is prevented.

  In addition, since the fuel pump reciprocates a small stroke length at a high speed by rotation of a cam disposed on the second sealing region B side, the contact surface of the inner peripheral side seal lip 11 and the inner peripheral side seal lip 13 are moved. The distance D between the contact surface and the contact surface is longer than the stroke length S of the shaft (plunger) 3. As a result, the occurrence of so-called scraping leakage, in which fuel, oil, or the like that remains on the shaft 3 without being scraped off by the seal lip, enters the sealed region on the opposite side by the reciprocating movement of the shaft 3, is suppressed.

  Moreover, as shown in the drawing, the sealing device 1 has a cross-sectional shape that is symmetrical in the axial direction, and can be assembled to the annular groove 21 regardless of the axial direction. Accordingly, there is no occurrence of erroneous assembly of the sealing device 1, and the mountability is improved.

<Manufacturing method of sealing device>
Next, with reference to FIG. 3, the manufacturing method of the sealing device based on a present Example is demonstrated. FIG. 3 is a schematic diagram illustrating the manufacturing process of the sealing device according to the present embodiment, where (a) is a schematic half sectional view of a resin molded product, and (b) is a schematic diagram illustrating a state where an annular recess is molded. (C) is a schematic half sectional view showing a state where a spring is mounted on the annular recess.

  First, as shown in FIG. 3 (a), annular recesses 15a and 16a that are recessed in the axial direction along the circumferential direction, or inner cylindrical portions 11a and 13a, and an outer peripheral cylinder are formed on both end surfaces in the axial direction. The substantially cylindrical resin molded product 1a having the portions 12a and 14a is molded with a mold and fired.

  Next, as shown in FIG. 3B, the recesses 15a and 16a are cut into annular recesses 15 and 16 to which the springs 17 and 18 can be attached. Specifically, both the side surfaces of the recesses 15a and 16a, that is, the outer peripheral surfaces of the inner cylindrical portions 11a and 13a and the outer peripheral cylinder so that the recesses 15a and 16a are gradually wider on the opening side than the bottom side. The inner peripheral surfaces of the portions 12a and 14a are cut and inclined. Here, the outer peripheral side surfaces of the recesses 15a, 16a, that is, the recess opening side edges of the inner peripheral surfaces of the outer cylindrical portions 12a, 14a are left without being cut, and protrusions for locking the springs 17, 18 Let them be parts 15b and 16b.

  Finally, as shown in FIG. 3C, springs 17 and 18 are attached to the annular recesses 15 and 16, respectively. The annular recesses 15 and 16 are expanded in the radial direction by the springs 17 and 18, and are formed at the distal ends of the inner peripheral protrusions 11 b and 13 b and the outer peripheral protrusions 12 b and 14 b formed by the cutting process, that is, the annular recesses. 15 and 16 are deformed so that the portions on both sides are inclined in the radial direction. As a result, seal lips 11, 12, 13, and 14 are formed in which the corners 11c, 13c, 12c, and 14c of the inner peripheral protrusions 11b and 13b and the outer peripheral protrusions 12b and 14b are lip tips. Become.

  Here, fine leakage due to the surface roughness of the seal surface can be reduced by finishing the roughness / finish of the mold to 6.3z or less without any machining.

  Thus, since the seal lip can be formed by pushing the springs 17 and 18 and deforming the seal member, a step such as cutting is not required to form the shape of the seal lip. Accordingly, the number of manufacturing steps can be reduced, and the manufacturing cost can be reduced.

(Example 2)
Next, with reference to FIG.4 and FIG.5, the sealing device which concerns on Example 2 of this invention is demonstrated. FIG. 4 is a schematic cross-sectional view of the sealing device according to the present embodiment. FIG. 5 is a schematic cross-sectional view showing a mounted state of the sealing device according to the present embodiment. In addition, about the structure which is common in Example 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted here. The configuration that is not particularly described and the operational effects thereof are the same as those in the first embodiment.

  As shown in FIG. 4, the sealing device 1 ′ according to the present embodiment includes a protruding portion 19 that protrudes in the radial direction on the outer peripheral surface of the seal body 10. The protrusion 19 may partially protrude from the outer peripheral surface of the seal body 10 or may be a flange-like protrusion that protrudes over the entire outer periphery of the seal body 10. Further, the position of the protrusion 19 is preferably symmetrical with respect to the axial direction by being the central part of the seal body 10 in the axial direction, but may be a position shifted from the central part.

When the housing 2 is configured so as to be divided into a plurality of members at the groove bottom portion of the annular groove 21, for example, as shown in FIG. 5, the annular groove 21 includes the seal retainer 2 a and the cylinder holder 2.
In the case where the step portion b is configured in combination, the sealing device 1 ′ is provided between the seal holder 2 a and the cylinder holder 2 b by the recess 23 formed in the groove bottom of the annular groove 21. It is sandwiched between and fixed. As a result, the sealing device 1 ′ is positioned with respect to the annular groove 21.

  Therefore, the mounting property of the sealing device to the annular groove is improved, and when the mating members are assembled after the sealing device is mounted, the sealing device is prevented from falling off the annular groove.

<Others>
In the above embodiment, the configuration in which the sealing device is mounted in the annular groove provided in the shaft hole of the housing has been described, but the sealing device may be mounted in the annular groove provided in the outer peripheral surface of the shaft. The present invention can be preferably applied.

  Moreover, although the said Example demonstrated only the usage example as a plunger seal in a fuel pump, as a use as a 2 liquid seal | sticker which seals between two sealing area | regions, it is not restricted to this.

1 is a schematic cross-sectional view of a sealing device according to Example 1. FIG. FIG. 3 is a schematic half cross-sectional view illustrating a mounting state of the sealing device according to the first embodiment. 6 is a schematic diagram illustrating a manufacturing process of the sealing device according to Embodiment 1. FIG. 6 is a schematic cross-sectional view of a sealing device according to Example 2. FIG. 6 is a schematic half cross-sectional view showing a mounting state of the sealing device according to Embodiment 2. FIG. It is typical sectional drawing of the sealing device which concerns on a prior art. It is typical sectional drawing of the sealing device which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing device 10 Seal main body 11, 13 Inner peripheral side seal lip 12, 14 Outer peripheral side seal lip 15, 16 Annular recess 17, 18 Spring 2 Housing 20 Axle hole 21 Annular groove 22 Groove bottom 3 Axis 30 Outer surface

Claims (6)

It is mounted in an annular groove provided in one member of a housing having a relatively reciprocating shaft and a shaft hole into which the shaft is inserted, and from the first sealing region on one axial side to the other axial side. In order to prevent the first sealing fluid from entering the second sealing region and to prevent the second sealing fluid from entering from the second sealing region to the first sealing region, the annular gap between the two members is sealed. A sealing device for
A first seal lip extending toward the first sealing region and contacting the groove bottom surface of the annular groove;
A second seal lip extending toward the first sealing region and slidingly contacting the other member of the two members;
A first annular recess formed between the first seal lip and the second seal lip and opening into a first sealing region;
A first biasing member mounted in the first annular recess, biasing the first seal lip toward the bottom of the annular groove, and biasing the second seal lip toward the other member. ,
A first seal portion having
A third seal lip extending toward the second sealing region and contacting the groove bottom surface of the annular groove;
A fourth seal lip extending toward the second sealing region and slidingly contacting the other member;
A second annular recess formed between the third seal lip and the fourth seal lip and opening to a second sealing region;
A second urging member that is mounted in the second annular recess, urges the third seal lip toward the bottom of the annular groove, and urges the fourth seal lip toward the other member. ,
A second seal part having
The surface where the first seal lip and the third seal lip are in contact with the bottom surface of the annular groove, and the surface where the second seal lip and the fourth seal lip are in sliding contact with the other member are gold Sealing device characterized by being a surface formed by a mold   The first seal lip, the second seal lip, the third seal lip, and the fourth seal lip are urged by annular recesses that are formed on both axial end surfaces of the cylindrical resin molded product and that open in the axial direction. The sealing device according to claim 1, wherein the sealing device is formed by mounting a member and expanding the annular concave portion in a radial direction by the biasing member.   The sealing device according to claim 1 or 2, wherein a distance between the second seal lip and the fourth seal lip is longer than a stroke length of reciprocation of the shaft.   The sealing device according to any one of claims 1 to 3, wherein the sealing device has an axially symmetric shape.   The sealing device according to any one of claims 1 to 4, further comprising a positioning protrusion that is sandwiched and fixed between a plurality of members that constitute the annular groove portion of the one member. A method for manufacturing a sealing device according to any one of claims 1 to 5,
A step of molding a cylindrical resin molded article having an annular recess recessed in the axial direction along the circumferential direction at both axial end faces;
Cutting the concave portion of the resin molded product into the first annular concave portion and the second annular concave portion; and
Attaching the first biasing member and the second biasing member to the processed first annular recess and the second annular recess;
The manufacturing method of the sealing device characterized by the above-mentioned.

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