JP2602575Y2 - Oil seal - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal used for automobiles and industrial machines.

[0002]

2. Description of the Related Art An oil seal is generally fixed to a machine main body side and has a lip in contact with a shaft at an inner peripheral portion thereof to prevent a fluid such as a liquid or a gas inside the machine from flowing out. It has both functions of preventing dust and dust from entering the inside of the machine from the outside. Such a function can be achieved by using only one lip. However, two lips are provided, one of which is to prevent the fluid from flowing out from the inside only, and the other is to provide a double to prevent the intrusion of dust or the like from the outside. Structures are known. The former lip is called a main lip, and the latter lip is called a dust lip or a sub lip.

FIG. 4 shows an example of this type of conventional oil seal. The oil seal 1 includes a reinforcing ring 2 having an L-shaped cross section and a rubber-like elastic body 3 integrally formed therewith.
A main lip 4 and a dust lip 5 are formed at the tip of the inner peripheral portion of the rubber-like elastic body 3. A spring 7 for pressing the tip of the main lip 4 against the shaft 6 is fitted on the outer peripheral surface of the main lip 4. This oil seal 1 is
The outer peripheral portion of the reinforcing ring 2 is used by being pressed into a mounting hole on the machine body side.

[0004] In such a double-structure oil seal, when the dust lip is provided with an interference in order to surely prevent the intrusion of dust and the like, when it is pressed against the shaft, the concave space between the main lip and the dust lip is formed. The inside air is removed by the pumping action of the main lip and that part becomes negative pressure, the main lip and the dust lip on both sides are attracted to each other inside, the tension force on the shaft increases, and the lip wears faster. There was a problem that the sealing performance was reduced. For this reason, measures have been taken to prevent negative pressure by providing ventilation holes in the dust lip.

[0005]

However, in such an oil seal provided with a vent hole in the dust lip,
In some cases, the ventilation holes were blocked by dust or the like, and did not serve as ventilation holes. In addition, since the dust lip is pressed against the shaft with an interference, the oil seal generates heat when used under high temperature and high peripheral speed conditions. There was a problem that the molding had to be performed with an excellent material, resulting in an increase in cost.

The present invention solves such a conventional problem by preventing a negative pressure in a concave space between a main lip and a dust lip, and at the same time, dust and the like enter the concave space. An object of the present invention is to provide an oil seal capable of discharging the oil seal even when the oil seal is discharged.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a main lip which is pressed against a shaft and the main lip.
And a non-contact dust lip axially located Rimojiku direction external side, on the inner surface of the dust lip, which was provided with a plurality of projections or grooves to generate an air flow toward the outside at least the axial direction is there.

[0008]

According to the present invention, according to the above structure, the air flow is generated outward in the axial direction by the projections or grooves provided on the inner surface of the dust lip. Can be discharged, and since the dust lip is not in contact with the shaft, the outside air flows between the main lip and the dust lip, so that a negative pressure does not occur in that portion.

[0009]

FIG. 1 shows the configuration of an embodiment of the present invention. The oil seal 11 includes a reinforcing ring 12 having an L-shaped cross section and a rubber-like elastic body 13 integrally formed therewith. A main lip 14 that comes into contact with the shaft 19 with an interference and a dust lip 15 that is not in contact with the shaft 19 are formed at the tip of the inner peripheral portion of the rubber-like elastic body 13. Main lip 14
A spiral shape which is inclined at the same angle in the same direction with respect to a generatrix parallel to the axis L in the unfolded state is provided on the entire periphery of the inner side surface, that is, the surface facing the concave space 16 between the main lip 14 and the dust lip 15. Are formed at equal intervals in the circumferential direction. The helix 17 generates an airflow inward in the axial direction indicated by arrow A, and
This is to assist the pumping action of No. 4. The helix 17 has a height of 0.1 mm or less, and the main lip 14
9 can be line-contacted, and the inclination direction is determined by the rotation direction of the shaft 19 or the oil seal 11. On the other hand, on the entire inner surface of the dust lip 15, that is, the surface facing the concave space 16, a plurality of projections 18 inclined in the opposite direction to the helix 17 at the same angle with respect to the generatrix parallel to the axis L in the unfolded state. Are formed at equal intervals in the circumferential direction. The projection 18 is for generating an airflow outward in the axial direction indicated by the arrow B, and has a height of 0.05 mm to
It has about 0.2 mm. A spring 20 for pressing the tip of the main lip 14 against the shaft 19 is fitted on the outer peripheral surface of the main lip 14. This oil seal 1
1 is used by pressing the outer peripheral portion of the reinforcing ring 12 into a mounting hole of the housing.

Next, the operation of the oil seal 11 will be described. The oil seal 11 is an oil seal 1
The housing on which the housing 1 is attached may be used for a machine that rotates or the shaft 19 may be used for a machine that rotates. However, the case where the shaft rotates will be described as an example. When the shaft 19 rotates in the direction of arrow C, airflow in the direction of arrow B is generated by the projections 18 provided on the inner surface of the dust lip 15, and even if dust or the like enters the concave space 16 from the outside, Can be discharged. Further, since a gap is formed between the dust lip 15 and the shaft 19 in a non-contact manner, no negative pressure is generated in the concave space 16. Furthermore, the helix 17 provided on the inner side surface of the main lip 14 generates an air flow in the direction of arrow A, and pushes back the fluid that is going to flow out of the machine to the outside, so that the sealing performance is further improved.

As described above, according to the above-described embodiment, since the plurality of projections 18 for generating the air flow outward in the axial direction are formed on the entire circumference of the inner surface of the dust lip 15, the main lip 14 Should dust or the like enter the recessed space 16 between the metal and the dust lip 15, it can be discharged.

In the above embodiment, the angle of inclination of the helical projection 18 is appropriately determined from the rotation speed and the like.
As shown in FIG. 2, a plurality of screw-shaped protrusions 28 whose inclination angles are increased with respect to the axis L are provided, or as shown in FIG. 3, a plurality of arc-shaped protrusions with the main lip 14 side convex. 38 may be provided to generate airflow outward in the axial direction, respectively. Also, the projections 18, 28,
Instead of 38, a groove having a similar depth or more may be formed. In this case, the space between the grooves corresponds to the protrusion in the above embodiment. The projections are more advantageous than the grooves from the viewpoint of mold production.

[0013]

(4) As described above, according to the present invention, the main lip which comes into pressure contact with the shaft and the outer side in the axial direction from the main lip.
A non-contact dust lip is provided on the shaft to be placed, and a plurality of projections or grooves for generating an air flow outward in the axial direction are provided on the inner surface of the dust lip. The negative pressure in the concave space can be prevented, and even if dust or the like enters the concave space, it can be discharged. Also, for sealing improvement, when axially inwardly directed Ke provided with a plurality of projections or grooves for generating an air flow on the inner surface of the main lip, since concave space is likely to become a negative pressure, the The application of the invention is more effective,
With the sealing property can be satisfactorily maintained, hot, so a particularly remarkable effect for use in high peripheral speed conditions.

[Brief description of the drawings]

FIG. 1 is a schematic partial sectional view of an oil seal showing an embodiment of the present invention.

FIG. 2 is a schematic partial sectional view of an oil seal showing another embodiment of the present invention.

FIG. 3 is a schematic partial sectional view of an oil seal showing still another embodiment of the present invention.

FIG. 4 is a schematic partial sectional view of an oil seal showing a conventional example.

[Explanation of symbols]

 Reference Signs List 11 oil seal 12 reinforcing ring 13 rubber-like elastic body 14 main lip 15 dust lip 16 concave space 17 helix 18, 28, 38 protrusion 19 shaft 20 spring

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tohru Shinohara 2 Nissan Motor Co., Ltd., Nissan Motor Co., Ltd. (72) Inventor Shuji Kurosaka 2 Takaracho, Kanagawa Ward, Yokohama City, Kanagawa Prefecture Nissan Motor Co., Ltd. (56) References JP-A-59-72359 (JP, U) JP-A-6-6831 (JP, U) JP-A-6-67694 (JP, U) JP-A 47-15880 (JP, Y1) J. 47-13774 (JP, Y1) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16J 15/32 311

Claims (2)

(57) [Scope of request for utility model registration] 1. A main lip pressed against a shaft and said main lip.
An oil seal comprising: a dust lip that is not in contact with a shaft positioned on the outer side in the axial direction; and a plurality of projections or grooves on the inner surface of the dust lip that generate airflow at least outward in the axial direction. . 2. The oil seal according to claim 1, further comprising a plurality of projections or grooves on the inner side surface of the main lip for generating an air flow inward in the axial direction.