JPH08247295A - Sealing device - Google Patents

Abstract

PURPOSE: To ensure an anti-dust property prevent a seal lip from damages and to improve the operability in assembly. CONSTITUTION: A sealing device for sealing a housing 3 and a rotary shaft 2 concentric thereto to be incorporated relatively rotatably to each other is provided with an annular seal body 4 mounted to the housing 3 and a seal lip 5 provided continuously on the seal body 5 and slidably sealingly contacting the rotary shaft. In the sealing device, a protective member 6 is provided on the rotary shaft inserting side of the seal body, which protects the seal body 4 when the rotary shaft of the seal body is inserted. The protective member 6 has an annular projection 63 projecting to the atmosphere side A, and a cover member 7 spaced by a predetermined gap from the annular projection is provided to cover the annular projection 63.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device such as an oil seal used in a diff part of an automobile, and more particularly to a sealing device assembled to a stepped shaft such as a spline shaft.

[0002]

2. Description of the Related Art As a conventional sealing device of this type, for example, there is one shown in FIG. That is, this sealing device 1
Reference numeral 00 is used in a diff part for an automobile, and seals between a stepped spline shaft 101 as a rotating shaft and a housing 102 assembled so as to be rotatable relative to each other.

The sealing device 100 is provided with an annular seal body 103 which is attached to a housing 102. The seal body 103 has a reinforcing ring 105 which is a cylindrical member having an L-shaped cross section having an inward flange 104. It has a rubber-like elastic body 106 integrally baked and fixed to the outer peripheral surface of the cylindrical portion 105A of the reinforcing ring 105 and the end surface A on the atmosphere side.

Further, the spline shaft 10 is attached to the inner end of the flange portion 104 of the reinforcing ring 105 continuously with the rubber-like elastic body 106.
1. A seal lip portion 1 slidably sealingly contacting the outer peripheral surface of 1.
07.

The seal lip portion 107 is the flange portion 10.
4 has a wedge-shaped main lip 108 extending from the inner end to the axial sealed fluid side O, and a substantially rectangular shape having a tapered cross-section extending from the inner end of the flange portion 104 to the axial atmosphere side A and tilting toward the radial spline shaft 101 side. It is made up of a secondary lip 109. The sub-lip 109 prevents dust from entering from the atmosphere side A.

The main lip 108 has a spring 1 for applying a tightening force to the spline shaft 101 on the outer peripheral side.
10 is mounted. Also, the thread groove 11 is formed on the surface on the atmosphere side A.
1 is formed, and the sealing action is enhanced by the pumping action of the thread groove 111.

At the inner end of the flange portion 104, a side lip 112 having a substantially rectangular cross section, which extends continuously to the rubber-like elastic body 106 toward the atmospheric side A in the axial direction and inclines radially outward.
Is provided.

The side lip 112 slidably and sealingly contacts the end surface of the step portion of the spline shaft 101 to prevent dust from entering from the atmosphere side A, and is used for so-called dust protection.

When the sealing device 100 is assembled between the housing 102 and the spline shaft 101, as shown in FIG.
Spline shaft 1 having a plurality of steps as shown in (b)
When inserting the sealing device 100 into 01, the seal body 103
Often, the spline portion 101A and the stepped portion (B portion in the drawing) are deformed and deformed, and the tip of the seal lip portion 107 that is continuously provided with the seal body 103 is scratched. Therefore, we pay close attention to the assembly.

Therefore, in order to improve the assemblability, an improved sealing device as shown in FIG. 4 has been used recently.

The sealing device 200 is the same as the sealing device 10 described above.
Similar to 0, it seals between a stepped spline shaft 101 as a rotating shaft and a housing 102 that is relatively rotatably assembled.

The sealing device 200 is provided with an annular seal body 201 which is attached to the housing 102. The seal body 201 has a reinforcing ring 203 having a substantially U-shaped cross section having a recess 202 opening to the atmosphere side A, and a reinforcement. It has a rubber-like elastic body 204 integrally and bake-fixed on substantially the entire inside and outside of the recess 202 of the ring 203. Also, the recess 20
The atmosphere side A end of the inner peripheral side portion of 2 has a radially inward flange portion 205.

The spline shaft 1 is attached to the inner end of the flange portion 205 of the reinforcing ring 203 continuously with the rubber-like elastic body 204.
01 has a seal lip portion 206 slidably sealingly contacting the outer peripheral surface thereof.

The seal lip portion 206 is the sealing device 1 described above.
Like 00, it extends from the inner end of the flange portion 205 to the axial sealed fluid side O, extends to the main lip 207 having a wedge-shaped cross section, and extends from the inner end of the flange portion 205 to the axial atmosphere side A to the radial direction spline shaft 101 side. The auxiliary lip 208 has a substantially rectangular shape with a tapered cross section.

The main lip 207 has a spring 2 for applying a tightening force to the spline shaft 101 on the outer peripheral side.
09 is installed. Further, a thread groove 210 having a shape different from that of the sealing device 100 is formed on the surface on the atmosphere side A.

The sealing device 200 is provided with a protector 211 as a protection member that protects the seal body 201 when the spline shaft 101 is inserted.

The protector 211 is a cylindrical member made of metal and having an L-shaped cross section having a radially inwardly facing flange portion 212. Then, the flange portion 212 is set to the atmosphere side A.
That is, with the shaft insertion side, the cylindrical portion 213 is fitted and attached to the inner peripheral surface of the outer peripheral portion of the recess 202 of the reinforcing ring 203 via the rubber-like elastic body 204.

Thus, the protector 21 is attached to the shaft insertion side.
1 is provided, it is possible to prevent the seal body 201 from hitting the spline portion 101A of the spline shaft 101 and the step portion (see FIG. 3B), and the main lip 207 and the sub The lip 208 is prevented from being scratched.

As a result, since it is not necessary to pay close attention when inserting the shaft, workability in assembly is improved accordingly.

[0020]

However, in the case of the sealing device 200 described above, the protector 211 made of metal is used.
Therefore, the side lip for dust protection provided in the sealing device 100 cannot be provided. Therefore, the sealing performance against dust from the atmosphere A is impaired.

The present invention has been made to solve the above-mentioned problems of the prior art, and the purpose thereof is to:
It is an object of the present invention to provide a sealing device capable of preventing scratches on a seal lip and improving workability in assembly while ensuring dust resistance.

[0022]

In order to achieve the above object, in the present invention, a seal is provided between a housing which is concentrically assembled with each other and is rotatable relative to each other, and a rotary shaft which is inserted into the housing. A sealing device comprising an annular seal body attached to the housing, and a seal lip continuously provided on the seal body and slidably sealingly contacting the rotary shaft. A protective member that protects the seal body is provided on the rotary shaft insertion side of the seal body at the time of insertion, and the protective member has an annular protrusion that protrudes to the atmosphere side. Is provided with a covering member.

Further, a displacement member which is displaced in the radial direction according to the diameter of the rotary shaft may be provided on the rotary shaft side of the protective member.

[0024]

In the above-structured sealing device, since the protective member for protecting the seal body is provided on the shaft insertion side, the seal body is protected when the shaft is inserted and is not deformed. Since the seal lip that is attached does not hit the shaft, it is not scratched. This allows
Since it is not necessary to pay close attention when inserting the shaft, workability in assembly is improved accordingly.

Further, since the covering member which covers the annular projection with a predetermined gap from the annular projection of the protection member is provided,
The labyrinth effect of the predetermined gap can prevent dust from entering from the atmosphere side.

Further, by providing a displacement member which is displaced in the radial direction according to the diameter of the rotary shaft on the rotary shaft side of the protective member, it is possible to absorb interference of the rotary shaft when the shaft is inserted. As a result, workability in assembly is further improved.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. 1 and 2 showing a sealing device according to an embodiment of the present invention, reference numeral 1 denotes a sealing device main body. In this embodiment, a rotary shaft is used in a diff part for an automobile like the conventional example. The stepped spline shaft 2 and the housing 3 that is assembled so as to be rotatable relative to each other are sealed, and the spline shaft 2 is inserted into the housing 3 and then assembled.

The sealing device 1 is generally provided with an annular seal body 4 attached to the housing 3, and a seal lip portion 5 which is continuously provided with the seal body 4 and slidably sealingly contacts the outer peripheral surface of the spline shaft 2. And a seal body 4 provided on the insertion side of the seal body 4 when the spline shaft 2 is inserted.
The protective cap 6 is provided as a protective member for protecting the above, and a slinger 7 which is attached to the outer peripheral surface of the spline shaft 2 on the atmosphere side A of the protective cap 6 and rotates together.

The seal body 4 comprises a reinforcing ring 8 and a rubber-like elastic body 9 integrally fixed to the reinforcing ring 8 by baking.

The reinforcing ring 8 is on the atmosphere side A, that is, the spline shaft 2.
It is a cylindrical member having a substantially U-shaped cross section having a recess 81 that is open on the insertion side. Further, the inner peripheral portion of the concave portion 81 is inclined inward in the radial direction, and the tip end portion thereof has a flange portion 8 which is directed radially inward.
Two.

A rubber-like elastic body 9 is integrally baked and fixed on almost the entire inner and outer sides of the reinforcing ring 8.

At the inner end of the flange portion 82 of the reinforcing ring 8, a seal lip portion 5 made of a rubber-like elastic body is provided continuously with the rubber-like elastic body 9.

The seal lip portion 5 has a main lip 51 and a sub lip 52, and the main lip 51 has a flange portion 82.
From the inner end to the axially sealed fluid side O, and has a wedge-shaped cross section. A flange portion 82 is provided on the atmosphere side A of the main lip 51.
A sub-lip 52 having a substantially rectangular shape with a tapered cross section is provided, which extends from the inner end to the air side A in the axial direction and is inclined inward in the radial direction.

The main lip 51 and the sub-lip 52 are slidably and sealingly contacted with the outer peripheral surface of the spline shaft 2. The main lip 51 seals the sealing fluid, and the sub-lip 52 from the atmosphere side A. It is designed to prevent dust from entering. A spring 10 for applying a tightening force to the spline shaft 2 is provided on the outer peripheral side of the main lip 51.

On the atmosphere side A of the seal body 4, that is, on the shaft insertion side,
An annular protective cap 6 made of resin (for example, PAT, PEND) is provided.

The protective cap 6 includes a cap body 61 having a substantially rectangular cross section, and a sealing fluid side O from the cap body 61.
The fitting portion 62 that protrudes to the end and is fitted into the recess 81 of the reinforcing ring 8.
And an annular protrusion 63 projecting from the cap body 61 to the atmosphere side A, and has a substantially T-shaped cross section. Further, on the inner peripheral side of the cap main body 61, there is provided a resin guide member 64 which continuously serves as a guide when the shaft is inserted.

The guide member 64 is provided all around the inner circumference of the cap body 61.
Is a member having an arc-shaped cross section that extends radially inward from a corner of the inner peripheral surface on the atmosphere side A and bends to the sealed fluid side O. The guide member 64 is thin and has a plurality of slits 65 formed at predetermined intervals in the circumferential direction.
A circumferential groove 66 is formed at the back end of the groove 5. This allows
The guide member 64 is easily bent (displaced) in the radial direction.

The fitting portion 62 of the protective cap 6 has a shape substantially conforming to the shape of the inner surface of the recess 81 of the reinforcing ring 8 of the seal body 4.

The protective cap 6 thus constructed is
By fitting the fitting portion 62 into the recess 81 of the seal body 4 via the rubber-like elastic body 9, the fitting portion 62 is attached to the seal body 4.

The seal body 4 provided with the protective cap 6 as described above is assembled between the housing 3 and the spline shaft 2 as follows by way of example.

The spline shaft 2 has a plurality of step portions as shown in FIG. 3B, and has a spline portion at the tip end in the axial direction.

First, the outer peripheral surface of the outer peripheral portion of the concave portion 81 of the reinforcing ring 8 of the seal main body 4 is fitted to the inner peripheral surface of the housing 3 so as to make sealing contact with the rubber-like elastic body 9. At this time,
The fitting portion 62 of the protective cap 6 is fitted into the recess 81,
A protective cap 6 is attached to the seal body 4.

The spline shaft 2 is inserted into the inner circumference of the seal body 4 in that state. At this time, the protective cap 6 prevents the seal body 4 from directly contacting the spline portion or the stepped portion of the spline shaft 2. Therefore, the seal body 4
Is protected and is not deformed, and the main lip 51 and the sub lip 52 that are continuously provided do not hit the spline shaft 2, so that scratches are prevented. As a result, since it is not necessary to pay close attention when inserting the shaft, it is possible to improve the workability in assembly by that much.

In addition, since the protective cap 6 is provided with the guide member 64 that flexes (displaces) in the radial direction, the guide member 64 can absorb radial interference when the spline shaft 2 is inserted. The workability is improved, and since the inner peripheral portion of the guide member 64 extends to the vicinity of the sliding surface of the seal lip portion 5, it is useful for preventing the seal lip portion 5 from being damaged.

Then, the seal body 4 is assembled as shown in FIG.
The slinger 7 attached to the spline shaft 2 and the annular projection 63 of the protective cap 6 are assembled with a predetermined gap as shown in FIG.

The slinger 7 is the atmosphere side A of the seal body 4.
And a cross-section L-shaped portion 72 that covers the end of the housing 3 and that is provided continuously from the end O of the sealed fluid side of the outer periphery of the recess 71.

The bottom surface of the recess 71, the atmosphere-side A end surface of the annular projection 63, the inner peripheral surface of the outer peripheral portion of the recess 71, and the outer peripheral surface of the annular projection 63 including the cap body 61 of the protective cap 6 are respectively provided. It has a predetermined minute gap. Also,
Predetermined minute gaps are also provided on the sealed fluid side O end surface of the L-shaped section 72 and the inner peripheral surface of the outer peripheral portion, and on the atmosphere side A end surface and the outer peripheral surface of the end portion of the housing 3, respectively.

On the other hand, on the inner peripheral surface of the end of the housing 3,
It has a taper surface 31 whose diameter increases toward the atmosphere-side A end surface, and the taper surface 31 and the outer peripheral surface of the seal body 4 and the sealing fluid-side O end surface of the L-shaped section 72 of the slinger 7 expand. The chamber 11 is formed, and the inner peripheral surface of the annular protrusion 63 and the cap body 61 (including the guide member 64) of the protective cap 6 are formed.
The expansion chamber 12 is formed by the end surface on the atmosphere side A and the outer peripheral surface of the inner peripheral portion of the recess 71 of the slinger 7.

Due to the labyrinth effect of the minute gaps and the expansion chambers 11 and 12, the invasion of dust from the atmosphere side A can be prevented. That is, it forms a sealing means for dust protection,
The dust resistance from the atmosphere side A is secured.

The protective cap 6 shown in the above embodiment is used.
May be formed integrally with the seal main body 4 instead of being a separate body, and the shape is not limited to the above-mentioned one, and any point may be used as long as it has an annular projection protruding toward the atmosphere side A.

Although the protective cap 6 is provided with the guide member 64, the shape thereof is not limited to the above-mentioned shape, and any shape may be used as long as it can absorb the interference of the spline shaft 2. Further, although the workability is slightly improved, the guide member 64 may be omitted.

The shape of the slinger 7 is not limited to the above, and the labyrinth effect may be somewhat reduced, but the slinger 7 may have a shape that does not cover the end of the housing 3.

[0053]

As described above, the present invention has the above-mentioned structure and action, and since the protective member for protecting the seal main body is provided on the shaft insertion side, the seal main body is protected and deformed when the shaft is inserted. Since the seal lips that are continuously provided do not hit the shaft, scratches can be prevented. As a result, since it is not necessary to pay close attention when inserting the shaft, it is possible to improve the workability in assembly by that much.

Since the covering member which covers the annular projection with a predetermined gap from the annular projection of the protection member is provided, the labyrinth effect of the predetermined clearance can prevent dust from entering from the atmosphere side. As a result, it is possible to secure the sealing resistance to the atmosphere side.

Further, by providing a displacement member on the rotary shaft side of the protective member, which is displaced in the radial direction according to the diameter of the rotary shaft, it is possible to absorb interference of the rotary shaft when the shaft is inserted. As a result, workability in assembly can be further improved.

[Brief description of drawings]

1A is a sectional view of a sealing device according to an embodiment of the present invention, and FIG. 1B is a sectional perspective view of a main part of a protective cap of FIG. 1A.

FIG. 2 is a sectional view showing a state where the sealing device of FIG. 1 is assembled between a spline shaft and a housing.

FIG. 3 (a) is a cross-sectional view of a conventional sealing device,
FIG. 7B is a diagram showing a step of inserting the spline shaft into the sealing device of FIG. 7A, and FIG. 7C is a sectional view showing a state in which the spline shaft and the housing are assembled. .

FIG. 4 (a) is a cross-sectional view of another conventional sealing device, and FIG. 4 (b) is a cross-sectional view showing a state of being assembled between a spline shaft and a housing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing device 2 Spline shaft (rotary shaft) 3 Housing 31 Tapered surface 4 Seal body 5 Seal lip part 51 Main lip 52 Sub lip 6 Protective cap (protective member) 61 Cap body 62 Fitting part 63 Annular protrusion 64 Guide member (displacement) Member) 65 Slit 66 Circumferential groove 7 Slinger (covering member) 71 Recessed portion 72 L-shaped section 8 Reinforcement ring 81 Recessed portion 82 Flange portion 9 Rubber-like elastic body 10 Spring 11, 12 Expansion chamber

Claims (2)

[Claims] 1. A housing for concentrically and relatively rotatably assembled to each other and a rotary shaft inserted into the housing to seal, and an annular seal body attached to the housing and a continuous seal body. And a seal lip that is provided on the rotary shaft and slidably sealingly contacts the rotary shaft, and a protective member that protects the seal main body on the rotary shaft insertion side of the seal main body when the rotary shaft is inserted into the seal main body. The sealing device is characterized in that the protective member has an annular protrusion that protrudes toward the atmosphere side, and a covering member that covers the annular protrusion with a predetermined gap from the annular protrusion. 2. The sealing device according to claim 1, wherein a displacement member that is displaced in the radial direction according to the diameter of the rotary shaft is provided on the rotary shaft side of the protective member.