JP6775295B2 - Sealing device for differential side - Google Patents

Description

The present invention relates to a sealing device used on the differential side of an automobile.

In general, an automobile differential device includes a differential case that houses a differential pinion gear and a differential side gear, a housing that rotatably supports the differential case, and a drive shaft that is connected to the differential side gear and inserted into a shaft hole of the housing. ing. In the annular space between the shaft hole of the housing and the drive shaft, a sealing device for the differential side that also prevents leakage of lubricating oil inside the housing (inside the sealing space) and prevents foreign matter from entering from the outside of the housing. (See, for example, Patent Document 1).

As shown in FIG. 6, the sealing device described in Patent Document 1 includes a seal body 114 mounted on the shaft hole 111a of the housing 111, and a deflector 115 mounted on the outer peripheral surface of the drive shaft 112. The seal body 114 includes a main lip portion 132 that contacts the drive shaft 112, a dust strip portion (auxiliary lip portion) 133 that contacts the drive shaft 112 on the outer side B of the housing 111 from the main lip portion 132, and this diameter. It has a side lip portion 134 that is provided on the outer side B of the strip portion 133, is on the outer side B, and extends obliquely outward in the radial direction. The deflector 115 has an annular plate portion 115b arranged along the radial direction, and the side lip portion 134 comes into contact with the annular plate portion 115b of the deflector 115 to cause foreign matter from the outer side B. Prevent intrusion.

Japanese Unexamined Patent Publication No. 2007-22506

A plurality of protrusions 132g are provided on the inner peripheral surface 132b (contact surface with the drive shaft 112) of the main lip portion 132 in the seal body 114 of Patent Document 1, and are provided on the side inside the housing 111 (inside the sealing space A). Even if the lubricating oil of the above is about to leak from between the drive shaft 112 and the main lip portion 132 to the outer side B, the protrusion 132 g causes a pumping action due to the relative rotation between the main lip portion 132 and the drive shaft 112, and the lubricating oil Is configured to be pushed back to the inner side of the housing 111.

However, since the space S between the main lip portion 132 and the dust strip portion 133 tends to have a negative pressure due to the pumping action, the main lip portion 132 and the dust strip portion 133 have a drive shaft as shown in FIG. It is often strongly pressed against the outer peripheral surface of 112. Therefore, the inner peripheral surface 132b of the main lip portion 132 comes into contact with the drive shaft 112 in a wide range, and the wear and heat generation of the entire inner peripheral surface 132b of the main lip portion 132 becomes large.

Therefore, an object of the present invention is to provide a sealing device for a differential side capable of suppressing wear and heat generation on the inner peripheral surface of the main lip portion.

The sealing device of the present invention
A sealing device for the differential side that seals between the sealing space inside the housing in which the shaft hole for inserting the drive shaft is formed and the outside of the housing.
A main lip portion that is attached to the shaft hole and contacts the outer peripheral surface of the drive shaft, and an auxiliary lip that is provided on the outer side of the main lip portion via a space portion and contacts the outer peripheral surface of the drive shaft. Equipped with a seal body that has a part
The main lip part
A first inner peripheral surface that is inclined so that the inner diameter becomes larger toward the outer side and at least a part of the drive shaft comes into contact with the outer peripheral surface of the drive shaft.
A regulating portion that prevents the entire surface of the first inner peripheral surface from coming into contact with the outer peripheral surface of the drive shaft,
A plurality of protrusions for returning the fluid in the housing formed on the first inner peripheral surface and leaking to the outer side into the housing by the pumping action accompanying the relative rotation with the drive shaft. With
The regulating unit includes a second inner peripheral surface of the first inner cylindrical disposed me along an obtuse angle and in a natural state to the axis of the drive shaft with respect to the peripheral surface,
The angle between the first inner peripheral surface and the second inner peripheral surface is set in the range of 130 ° to 170 °.

According to the above configuration, even when the main lip portion is strongly pressed against the outer peripheral surface of the drive shaft, the main lip is restricted from contacting the first inner peripheral surface with the outer peripheral surface of the drive shaft. Since the regulating portion is provided, the contact area of the first inner peripheral surface of the main lip portion with respect to the outer peripheral surface of the drive shaft can be reduced, and wear and heat generation on the first inner peripheral surface can be suppressed.

The main lip portion is for returning the fluid in the housing, which is formed on the first inner peripheral surface and is about to leak to the outer side, into the housing by a pumping action accompanying the relative rotation with the drive shaft. A plurality of protrusions may be further provided.
In this way, when a configuration is adopted in which the space between the main lip portion and the auxiliary lip portion tends to have a negative pressure due to the pumping action of the protrusions, the main lip portion is strongly pressed against the outer peripheral surface of the drive shaft. Therefore, it is more useful to provide the above-mentioned regulatory section.

The regulating unit, that have a second inner peripheral surface disposed substantially along the axis of the first inner obtuse angle relative to the circumferential surface and the drive shaft.
With such a configuration, when the negative pressure in the space between the main lip portion and the auxiliary lip portion is small (high pressure), the second inner peripheral surface of the regulating portion does not come into contact with the drive shaft, and the regulating portion is concerned. Wear and heat generation can be suppressed.
Further, a concave groove is formed on the outer side of the second cylindrical surface.
It is preferable that the angle of the internal angle between the second inner peripheral surface and the inner surface of the concave groove adjacent to the second inner peripheral surface is set in the range of 100 ° to 170 °.

According to the sealing device for the differential side of the present invention, it is possible to suppress wear and heat generation on the inner peripheral surface of the main lip portion.

It is sectional drawing which shows the sealing device which concerns on one Embodiment. It is sectional drawing which shows the main part of the seal body of a sealing device in an enlarged manner. It is sectional drawing which shows the side lip part of the seal member at the time of the maximum tightening allowance. It is sectional drawing which shows the main lip part and auxiliary lip part of a seal member at the time of strong pressure contact. It is a graph which shows the relationship between the tightening allowance of the side lip of a seal member, and the reaction force. It is sectional drawing which shows the conventional sealing apparatus. It is sectional drawing which shows the side lip part at the time of the maximum tightening margin in the conventional seal member. FIG. 5 is a cross-sectional view showing a main lip and an auxiliary lip when strongly pressed against a drive shaft in a conventional sealing member.

Hereinafter, embodiments of the sealing device will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a sealing device according to an embodiment of the present invention. The sealing device 10 is connected to a housing 11 that rotatably supports a differential case accommodating a differential pinion gear and a differential side gear in a differential device of an automobile, and is inserted into a shaft hole 11a formed in the housing 11. It is a sealing device for the differential side used between the drive shaft (rotating shaft) 12 and the housing.

The sealing device 10 is mounted in an annular space formed between the drive shaft 12 and the housing 11 which rotate relative to each other, and a sealing fluid such as a lubricating oil sealed in the sealing space A inside the housing 11 is introduced. Prevents leakage to the outer side B of the housing 11.
The sealing device 10 includes a sealing body 14 and a deflector (contact member) 15.
The seal body 14 is composed of an annular core metal 21 having a substantially L-shaped cross section, a seal member 22 fixed to the core metal 21, and an annular spring ring 23.

The core metal 21 is an annular member made of metal (for example, SPCC), and has a cylindrical cylindrical portion 21a arranged coaxially with the drive shaft 12 and a radial end portion of the cylindrical portion 21a in the axial direction. It is composed of an annular plate portion 21b that is curved inward.

The sealing member 22 is made of an elastic member such as synthetic rubber (for example, acrylonitrile-butadiene rubber (NBR), acrylic rubber (ACM)), and is fixed to the core metal 21 by bonding or baking by vulcanization. The seal member 22 is formed in an annular shape, and has a main body portion 31, a main lip portion 32, an auxiliary lip portion 33, and a side lip portion 34.

The main body 31 is provided on the outer peripheral surface of the cylindrical portion 21a of the core metal 21 and is fixed to the shaft hole 11a of the housing 11, and the side surface provided on the side surface of the outer side B of the annular plate portion 21b. A portion 31b and an inner peripheral portion 31c that covers the inner peripheral portion of the annular plate portion 21b are provided. The outer peripheral portion 31a, the side surface portion 31b, and the inner peripheral portion 31c are integrally formed. The outer peripheral portion 31a is arranged along the axial direction, and the side surface portion 31b is arranged along the radial direction.

<Structure of main lip portion 32>
The main lip portion 32 extends toward the sealed space A side in the radial direction of the inner peripheral portion 31c of the main body portion 31. A peripheral groove 32a is formed on the outer peripheral surface of the main lip portion 32. A spring ring 23 called a garter spring is mounted on the peripheral groove 32a. The spring ring 23 tightens the main lip portion 32 inward in the radial direction.

FIG. 2 is an enlarged cross-sectional view showing a main part of the seal body 14 of the sealing device 10. In FIG. 2, a seal body 14 in a natural state that is not loaded from the outside is shown.
As shown in FIGS. 1 and 2, the main lip portion 32 comes into contact with the outer peripheral surface of the drive shaft 12 with a tightening margin to prevent the sealing fluid in the sealing space A from leaking to the outer side B. The main lip portion 32 has a substantially V-shape in which the cross-sectional shape on the inner side in the radial direction becomes thinner in the radial direction (the width dimension in the axial direction becomes smaller). Therefore, the inner peripheral surface of the main lip portion 32 has a first inclined surface 32b on the outer side B and a second inclined surface 32c on the sealed space A side.

The first inclined surface 32b is inclined so that the inner diameter becomes larger toward the outer side B, and the second inclined surface 32c is inclined so that the inner diameter becomes larger toward the sealed space A side. The minimum diameter portion (top) of the main lip portion 32, which is the boundary portion between the first inclined surface 32b and the second inclined surface 32c, is referred to as the first lip tip portion 32d. Further, on the outer side B from the first inclined surface 32b, a cylindrical cylindrical surface 32e formed in a direction substantially along the axial direction C is formed. The first inclined surface 32b and the cylindrical surface 32e intersect at an obtuse angle. The cylindrical surface 32e constitutes a contact surface (second inner peripheral surface) that can come into contact with the outer peripheral surface of the drive shaft 12 as described later.

The angle θ1 of the internal angle between the first inclined surface 32b and the second inclined surface 32c is an obtuse angle, and is, for example, about 122 °. θ1 can be set, for example, in the range of 95 ° to 140 °.
The angle θ2 between the first inclined surface 32b and the cylindrical surface 32e is, for example, about 157 °. θ2 can be set, for example, in the range of 130 ° to 170 °.

A concave groove 37 is formed on the outer side B of the cylindrical surface 32e. The angle θ3 of the internal angle between the inner surface 37a of the concave groove 37 adjacent to the cylindrical surface 32e and the cylindrical surface 32e is an obtuse angle, for example, about 140 °. θ3 can be set, for example, in the range of 100 ° to 170 °.

The first inclined surface (first inner peripheral surface) 32b of the main lip portion 32 functions as a sealing surface that contacts the outer peripheral surface of the drive shaft 12. As shown in FIG. 1, a plurality of protrusions 32g are formed on the first inclined surface 32b so as to be inclined at a required angle in the circumferential direction with respect to the axial direction. By forming the protrusion 32g on the first inclined surface 32b, the contact portion between the main lip portion 32 and the drive shaft 12 will leak to the outer side B as the seal member 22 and the drive shaft 12 rotate relative to each other. The pumping action of returning the sealing fluid in the sealing space A to the sealing space A is exhibited.

As shown enlarged in FIG. 2B, the cylindrical surface 32e and the inner surface 37a of the concave groove 37 project radially inward from the first inclined surface 32b in the direction a perpendicular to the first inclined surface 32b. The protrusion 38 is formed. The protrusion 38 constitutes a regulation portion that regulates the entire surface of the first inclined surface 32b from coming into contact with the outer peripheral surface of the drive shaft 12.

<Structure of auxiliary lip portion 33>
As shown in FIGS. 1 and 2, the auxiliary lip portion 33 contacts the outer peripheral surface of the drive shaft 12 with a tightening allowance to prevent foreign matter from entering the sealed space A mainly from the outer side B. The auxiliary lip portion 33 has a substantially V-shape in which the cross-sectional shape inside the auxiliary lip portion 33 becomes thinner in the radial direction (the width dimension in the axial direction becomes smaller). Therefore, the inner peripheral surface of the auxiliary lip portion 33 has a third inclined surface 33a on the sealing space A side and a fourth inclined surface 33b on the outer side B.

The minimum diameter portion (top) of the auxiliary lip portion 33, which is the boundary portion between the third inclined surface 33a and the fourth inclined surface 33b, is referred to as the second lip tip portion 33c. The third inclined surface 33a of the auxiliary lip portion 33 functions as a sealing surface that contacts the outer peripheral surface of the drive shaft 12.
The angle θ4 of the internal angle between the third inclined surface 33a and the fourth inclined surface 33b is an obtuse angle, and is, for example, about 111 °. The angle θ4 can be set, for example, in the range of 95 ° to 150 °.

<Action of main lip 32>
Since a concave groove 37 is formed between the main lip portion 32 and the auxiliary lip portion 33, between the auxiliary lip portion 33, the main lip portion 32, and the outer peripheral surface of the drive shaft 12 in which they come into contact. An annular first space portion S1 (see FIG. 1) is formed in.
Since the protrusions 32g are formed on the first inclined surface 32b of the main lip portion 32, the air in the first space portion S1 is discharged to the sealed space A side by the pumping action of the protrusions 32g, and the first The inside of the space portion S1 tends to have a negative pressure. Then, when the inside of the first space portion S1 becomes negative pressure, the main lip portion 32 and the auxiliary lip portion 33 are strongly pressed against the outer peripheral surface of the drive shaft 12. This state is shown in FIG.

As shown in FIG. 4, in the main lip portion 32, the first inclined surface 32b contacts the outer peripheral surface of the drive shaft 12, but the protrusion (regulating portion) 38 is adjacent to the outer side B of the first inclined surface 32b. The first inclined surface 32b does not come into contact with the outer peripheral surface of the drive shaft 12 as a whole, and a part of the first inclined surface 32b is in a floating state. Therefore, a gap c is formed between the main lip portion 32 and the drive shaft 12.

As shown in FIG. 8, in the case of the conventional seal body 114, the main lip portion 132 does not have the protrusion 38 as in the present embodiment, so that the entire surface of the first inclined surface 132b comes into contact with the drive shaft 12. doing. Therefore, the wear and heat generation of the entire first inclined surface 132b become large.
On the other hand, in the present embodiment, as shown in FIG. 4, the contact portions of the main lip portion 32 with respect to the drive shaft 12 are dispersed, and the entire surface of the first inclined surface 32b of the main lip portion 32 comes into contact with the drive shaft 12. Can be suppressed. Therefore, wear and heat generation of the first inclined surface 32b of the main lip portion 32 can be suppressed.

<Structure of side lip portion 34>
As shown in FIG. 1, the side lip portion 34 of the seal member 22 extends from the boundary portion between the side surface portion 31b and the inner peripheral portion 31c of the main body portion 31 to the outer side B. The side lip portion 34 is formed in a shape bent in multiple stages. Specifically, the side lip portion 34 includes a base end portion 41, an intermediate portion 42, 43, and a tip portion 44 in this order from the sealed space A side. Then, the space between the base end portion 41 and the intermediate portion 42 and the space between the intermediate portion 43 and the tip portion 44 are bent, respectively.

As shown in FIG. 2, the side lip portion 34 of the present embodiment has a length (width with respect to the axial direction C) L1 of the main body portion 31 of the seal member 22 from the side surface portion 31b, for example, about 12.1 mm. ing.
The base end portion 41 extends obliquely from the side surface portion 31b of the seal member 22 on the outer side B and inward in the radial direction. The angle θ5 between the base end portion 41 and the side surface portion 31b is an obtuse angle, for example, about 106 °. The angle θ5 can be set, for example, in the range of 95 ° to 150 °. The base end portion 41 of the present embodiment has a length (width with respect to the axial direction C) L2 from the side surface portion 31b of the main body portion 31 of, for example, about 2.4 mm. The length L2 of the base end portion 41 is about 20% of the length L1 of the entire side lip portion 34.

The intermediate portions 42 and 43 have a base end side intermediate portion 42 and a tip end portion side intermediate portion 43. The base end side intermediate portion 42 extends obliquely from the tip end of the base end portion 41 on the outer side B and outward in the radial direction. The angle θ6 between the base end portion 41 and the base end portion side intermediate portion 42 is an obtuse angle, for example, about 97 °. The angle θ6 is set to be smaller than the angle θ5. Further, the angle θ6 can be set in the range of, for example, 95 ° to 150 °. The side lip portion 34 is formed in a shape that is convex inward in the radial direction at the proximal end portion 41 and the proximal end portion side intermediate portion 42.

The tip-side intermediate portion 43 extends obliquely from the tip of the proximal end-side intermediate portion 42 to the outer side B and radially outward. The angle θ7 between the base end side intermediate portion 42 and the tip end side intermediate portion 43 is an obtuse angle, for example, about 120 °. The angle θ7 is set to be a value larger than the angles θ5 and θ6. Further, the angle θ7 can be set in the range of, for example, 95 ° to 150 °. Further, the tip end side intermediate portion 43 is set so that the inclination angle θ10 with respect to the axial direction C is smaller than the inclination angle θ9 in the proximal end portion side intermediate portion 42.

The intermediate portions 42 and 43 of the present embodiment have a length (width) L3 in the axial direction C of about 7.2 mm. Of these, the length L4 of the base end side intermediate portion 42 is about 2.2 mm, and the length L5 of the tip end side intermediate portion 43 is about 5.0 mm. The length L3 of the intermediate portions 42 and 43 is about 60% of the length L1 of the entire side lip portion 34, and the lengths L4 and L5 between the base end side intermediate portion 42 and the tip end side intermediate portion 43. The ratio of is about 3: 7.

The side lip portion 34 is formed in a shape that is convex outward in the radial direction at the portion of the base end side intermediate portion 42 and the tip end portion side intermediate portion 43. Therefore, the inner peripheral surfaces of the intermediate portions 42 and 43 of the side lip portion 34 are formed in a concave shape. The inner peripheral surfaces of the intermediate portions 42 and 43 are formed in a concave shape, so that the side lip portion 34 has a space D between the tip portion 44 and the base end portion 41.

The tip portion 44 extends obliquely from the tip end of the tip end side intermediate portion 43 on the outer side B and outward in the radial direction. The angle θ8 between the tip end side intermediate portion 43 and the tip end portion 44 is an obtuse angle, for example, about 154 °. The angle θ8 is set to be larger than the angle θ7. Further, the angle θ8 can be set in the range of, for example, 100 ° to 170 °. The tip portion 44 of the present embodiment has a length (width) L6 in the axial direction C of about 2.5 mm. The length L6 of the tip portion 44 is about 20% of the length L1 of the entire side lip portion 34.
The side lip portion 34 is formed in a shape that is convex inward in the radial direction at the tip portion side intermediate portion 43 and the tip portion 44 portion.

The tip portion 44 functions as a seal portion that comes into contact with the deflector 15 attached to the drive shaft 12. A groove 44b extending in the circumferential direction is formed on the inner peripheral surface 44a of the tip portion 44. The groove 44b functions to hold the oil. Therefore, heat generation and wear at the tip portion 44 can be suppressed.

As shown in FIG. 1, the deflector 15 has a cylindrical cylindrical portion 15a fitted to the outer peripheral surface of the drive shaft 12 and an annular shape bent outward in the radial direction from one end in the axial direction of the cylindrical portion 15a. It has an annular plate portion 15b of the above. The deflector 15 is fixed to the drive shaft 12 so that the annular plate portion 15b faces the outer side B of the side lip portion 34 of the seal body 14.

The inner peripheral surface of the side lip portion 34 of the seal body 14 has a tightening allowance and comes into contact with the deflector 15, and the inner peripheral surface of the side lip portion 34, the annular plate portion 15b of the deflector 15, and the drive shaft 12 A second space portion S2 is formed between the outer peripheral surface and the outer peripheral surface of the auxiliary lip portion 33.

The tightening allowance of the side lip portion 34 varies greatly depending on the relative position when the housing 11, the drive shaft 12, the seal body 14, and the deflector 15 are assembled, the amount of sliding of the drive shaft 12 in the axial direction during operation, and the like. For example, the slide amount of the drive shaft 12 during operation is about 3 mm, and the tightening allowance range E of the side lip portion 34 in consideration of this slide amount is about 1 mm to 7 mm. The shape of the side lip portion 34 is designed so that it can be appropriately contacted with the deflector 15 regardless of the size of the tightening allowance.

Specifically, the side lip portion 34 is configured such that its tip portion 44 always contacts the deflector 15. In FIG. 1, the position of the deflector 15 when the tightening allowance of the side lip portion 34 is the minimum is shown by a solid line, and the position of the deflector 15 when the tightening allowance of the side lip portion 34 is the maximum is shown by a two-dot chain line. There is. Further, FIG. 3 shows the state of the side lip portion 34 when the tightening allowance is maximum.

The side lip portion 34 includes intermediate portions 42, 43 between the base end portion 41 and the tip end portion 44, and the intermediate portions 42, 43 have an inner peripheral surface formed in a concave shape, and the tip end portion 44 and the base end portion 41 are formed. There is a vacant space D between and. Therefore, as shown in FIG. 3, the tightening allowance of the side lip portion 34 is maximized, and even when the side lip portion 34 is greatly bent outward in the radial direction, the tip portion 44 comes into contact with the deflector 15 and other portions ( The intermediate portions 42, 43 and the base end portion 41) do not come into contact with the deflector 15. Therefore, the tip portion 44 can be maintained in contact with the deflector 15, and the contact surface pressure between the tip portion 44 and the deflector 15 can be sufficiently secured, so that foreign matter can enter from the external side B. It can be reliably prevented.

Further, the base end portion 41 of the side lip portion 34 extends radially inward from the side surface portion 31b and the inner peripheral portion 31c of the seal member 22, and the base end portion side intermediate portion 42 extends from the tip end of the base end portion 41. It extends radially outward. Due to such a structure, as shown in FIG. 3, even if the tightening allowance is expanded, the base end portion 41 does not elastically deform so much outward in the radial direction, and the base end portion 41 and the base end portion side intermediate portion 42 The elastic deformation between them is large. As a result, it is possible to follow the change in the tightening allowance of the side lip portion 34 without affecting the contact state between the deflector 15 and the tip portion 44.

FIG. 5 is a graph showing the relationship between the tightening allowance of the side lip portion 34 and the reaction force of the side lip portion 34. FIG. 5 shows a comparison between the seal body 14 having the shape of the above embodiment and the seal body 114 of the prior art (see FIG. 6). Further, FIG. 7 shows the shape of the side lip portion 134 when the tightening allowance is maximized in the seal body 114 of the prior art.

In the seal body 114 of the prior art, as shown in FIG. 6, substantially the entire side lip portion 134 has a shape that is inclined in a tapered shape. Therefore, as shown in FIG. 7, when the tightening allowance becomes large, the side The lip portion 134 bends outward in the radial direction while expanding the contact area with the deflector 115. At the same time, the peak of the contact surface pressure gradually moves inward in the radial direction from the tip portion, and the tip portion of the side lip portion 134 tends to rise from the deflector 15. Therefore, there is a problem that the effect of preventing the invasion of foreign matter is reduced.

Further, as shown in FIG. 5, in the conventional seal body 114, the reaction force of the side lip portion 134 also increases as the tightening allowance increases, but when the tightening allowance exceeds a certain value (for example, 3 mm), it is indicated by a dotted line. The reaction force increases sharply. Therefore, as described above, the side lip portion 134 is worn out and heat is increased.

On the other hand, in the case of the seal main body 14 of the present embodiment, as shown in FIG. 3, even if the tightening allowance is large, the tip portion 44 can be maintained in contact with the deflector 15 and moreover. The intermediate portions 42 and 43 do not come into contact with the deflector 15. Therefore, the effect of preventing the invasion of foreign matter can be suitably maintained.

Further, as shown in FIG. 5, the reaction force of the side lip portion 34 rises relatively rapidly from the time when the tightening allowance starts to expand until it reaches a predetermined value (for example, up to 1.6 mm). After exceeding the predetermined value, it starts to decrease, and then the reaction force gradually decreases as the tightening allowance increases. Therefore, even if the tightening allowance changes within the above-mentioned tightening allowance range (for example, 1.0 to 7.0 mm), excessive wear and heat generation can be suppressed while maintaining the sealing property.

The sealing device of the present invention is not limited to the above embodiment, and the dimensions, materials, shapes, relative arrangements, etc. of the components can be appropriately changed within the scope of the present invention.
For example, the protrusion 38 of the above embodiment is formed in a mountain shape by the cylindrical surface 32e and the inner surface 37a, but the present invention is not limited to this, and the protrusion 38 of the main lip portion 32 with respect to the drive shaft 12 of the first inclined surface 32b. Various shapes can be adopted as long as the contact area can be reduced.

In the above embodiment, the inner peripheral surfaces of the side lip portions 34 are formed to be concave by bending the intermediate portions 42 and 43 at the boundary between the base end side intermediate portion 42 and the tip end side intermediate portion 43. , The inner peripheral surface of the intermediate portion may be curved to form a concave shape.
The base end portion 41 of the side lip portion 34 may extend on the outer side B and diagonally outward in the radial direction.

10: Sealing device 11: Housing 11a: Shaft hole 12: Drive shaft 14: Seal body 32: Main lip portion 32b: First inclined surface (first inner peripheral surface)
32e: Cylindrical surface (second inner peripheral surface)
32g: Protrusion 33: Auxiliary lip 38: Protrusion A: Sealed space B: External side S1: First space

Claims (2)

A sealing device for the differential side that seals between the sealing space inside the housing in which the shaft hole for inserting the drive shaft is formed and the outside of the housing.
A main lip portion that is attached to the shaft hole and contacts the outer peripheral surface of the drive shaft, and an auxiliary lip that is provided on the outer side of the main lip portion via a space portion and contacts the outer peripheral surface of the drive shaft. Equipped with a seal body that has a part
The main lip part
A first inner peripheral surface that is inclined so that the inner diameter becomes larger toward the outer side and at least a part of the drive shaft comes into contact with the outer peripheral surface of the drive shaft.
A regulatory unit that regulates the entire surface of the first inner peripheral surface from coming into contact with the outer peripheral surface of the drive shaft,
A plurality of protrusions for returning the fluid in the housing formed on the first inner peripheral surface and leaking to the outer side into the housing by the pumping action accompanying the relative rotation with the drive shaft. With
The restricting portion is provided adjacent to the outer side of the first inner peripheral surface, I along the axis of said drive shaft and nature an obtuse angle relative to the first inner circumferential surface It has a cylindrical second inner peripheral surface that is arranged.
A sealing device for a differential side in which the angle between the first inner peripheral surface and the second inner peripheral surface is set in the range of 130 ° to 170 °. A concave groove is formed on the outer side of the second cylindrical surface.
Claim 1 in which the angle of an internal angle between the second inner peripheral surface and the inner surface of the concave groove adjacent to the second inner peripheral surface is set in the range of 100 ° to 170 °. Sealing device for differential side described in.

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