JPH0656568U - Oil seal - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an oil seal that can maintain a good sealing property. A large number of protruding ribs 8 that are inclined with respect to the seal lip tip edge 3a are formed on the air side inclined surface 6, and the rib 8 from the air side inclined surface 6 in the seal lip tip edge side portion is formed. In the oil seal formed so that the height is relatively lower than that of the other portion, and the annular groove 12 is formed at the seal lip tip edge side portion of the oil side inclined surface 7, the oil side inclined surface 7 An oil seal in which a large number of protruding ribs 13 are formed in the annular groove 12 at predetermined circumferential intervals.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an oil seal having ribs for improving hermeticity.

[0002]

[Prior art]

 In general, it is known that an oil seal has a pumping action of pushing back the oil leaking from the oil side of the seal lip to the air side to the oil side again. In order to increase the pumping action and improve the sealing action of the oil seal, conventionally, as shown in FIG. 5, a cross section wedge composed of an air side inclined surface 52 and an oil side inclined surface 53 inclined in opposite directions. Provided with a rubber-made seal portion 50 in which a circular annular seal lip 51 is formed, and the air-side inclined surface 52 has a large number of chevron-shaped cross-sections inclined toward the tip edge 51a of the seal lip 51. An oil seal is known in which 54 is formed at predetermined intervals in the circumferential direction. In this oil seal, as can be understood from the contact state of the tip edge 51a of the seal lip 51 with respect to the shaft (not shown) in FIG. 6, the seal lip 51 rotates in accordance with the rotation of the shaft in the direction of arrow A. The oil leaking to the air side 55 due to an abnormality such as a scratch on 51 is forcibly returned to the oil side 56 along the rib 54 (direction of arrow X).

[0003]

[Problems to be solved by the device]

 In order to increase the pumping action, the rib height may be increased, but the contact drag force that the rib 54 receives from the shaft increases, and the tip edges 51a of the seal lip 51 on both sides of the rib 54 increase. May be deformed and a portion with a small contact width may be formed at the base portion B of the contact portion of the rib 54, which causes a new problem of oil leakage in extreme cases. In order to solve such a problem, FIG. 7 (Shokaihei 4-17566) is proposed. That is, a rubber seal member 70 having an annular seal lip 71 having a wedge-shaped cross section, which is composed of an air-side inclined surface 72 and an oil-side inclined surface 73 which are inclined in mutually opposite directions, is provided. A large number of protruding ribs 74 that are inclined with respect to the seal lip tip edge 71a are formed on the surface 72, and the height of the rib 74 from the air side inclined surface 72 of the seal lip tip edge 71a side portion 74a is higher. It is known that the oil seal is formed to have a height lower than that of the other portion 74b, and an annular groove 75 is formed in a portion of the oil side inclined surface 73 on the seal lip tip edge 71a side. This oil seal assists the tightening force of the seal lip 71 on the shaft by means of an annular gutter spring 79 provided on the outer peripheral surface of the seal lip 71. The center of the rotor spring 79 is offset from the front edge 71a of the seal lip 71 in the axial direction toward the lip root by a predetermined amount h. The height of the rib 74 will be described in detail below. The air-side inclined surface 72 is formed in a two-step taper shape with a first surface 76 on the base side of the lip 71 and a second surface 77 near the tip edge 71a of the lip 71, and the axis O The angle α of the first surface 76 and the angle β of the second surface 77 with respect to −O are set to α <β. Therefore, since each rib 74 has a ridge line 78 along the first surface 76 so that the height from the first surface 76 is constant, the height of the rib 74 is the same as that of the seal lip 71. It gradually decreases as it approaches the leading edge 71a. With such a configuration, even if the height of the rib 74 is set high, the height of the seal lip tip edge side portion 74a of the rib 74 is relatively low, so that the rib is not attached when mounted on the shaft. The deformation of the seal lip tip edge side portion 74a of the seal lip 74 is suppressed, and the rigidity of the tip edge 71a portion of the seal lip 71 can be weakened by the annular groove 75 formed in the air side inclined surface 72. It is expected that the contact area of the tip edge with the shaft will be stable and the followability will be improved, and the pump action will be maintained well. However, in the oil seal of FIG. 7, although the above effect can be expected, conversely, due to the eccentricity of the shaft, the load h is affected by the offset amount h of the lip tip edge 71a and the center of the gutter spring 79. The receiving part may move from the tip edge 71a of the lip 71 to the C portion of the air-side inclined surface 72, and the lip tip may rise from the shaft and come out of contact with the shaft. In this case, the sealing performance will deteriorate. . SUMMARY OF THE INVENTION An object of the present invention is to solve the above technical problems and to provide an oil seal capable of obtaining a high pumping action and ensuring a good sealing property.

[0004]

Means for Solving the Problems As means for solving the above-mentioned problems, a rubber-made annular seal lip having a wedge-shaped cross section formed of an air-side inclined surface and an oil-side inclined surface inclined in opposite directions is formed. A seal member is provided, and a large number of protruding ribs that incline with respect to the tip edge of the seal lip are formed on the air-side inclined surface, and the air-side inclined surface at the seal lip tip edge side portion of the rib. The oil-side inclined surface of the oil-side inclined surface of the oil-side inclined surface formed with an annular groove at the tip end edge side of the seal lip of the oil-side inclined surface. In the above annular groove, a large number of protruding ribs are formed at predetermined intervals on the circumference.

[0005]

[Action]

 According to the oil seal configured as described above, a large number of ribs extending from the lip tip edge to the annular groove are formed on the oil side inclined surface of the seal lip, so that the reaction force against deformation of the lip from the shaft, that is, the deformation resistance increases. In addition, the magnitude of the lip pressure can be clarified, and a high pump action can be maintained and the sealing performance can be maintained.

[0006]

【Example】

 Hereinafter, a specific embodiment of the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of the present invention, FIG. 1 is a sectional view of an oil seal, and FIG. 2 is an enlarged perspective view of a main part. This oil seal is an annular member formed by integrally vulcanizing and adhering an elastic member 1 made of rubber such as NBR and a metal cored bar 2, and is a seal member on the inner peripheral portion of the elastic member 1. 1a is provided with a seal lip 3 and a dust lip 4 which come into contact with the shaft and seal between the shaft and the shaft.

The seal lip 3 has a wedge-shaped cross section having an air-side inclined surface 6 and an oil-side inclined surface 7 that are inclined in opposite directions on the inner peripheral surface thereof. In FIG. 1, the right side is the oil side and the left side is the air side. Further, on the outer peripheral surface of the seal lip 3, an annular gutter spring 5 is provided to assist the tightening force of the seal lip 3 on the shaft.

The air-side inclined surface 6 of the seal member 1 a has a first surface 9 that occupies most of the air-side inclined surface 6 on the side of the root portion of the seal lip 3 and the tip of the seal lip 3. It is formed in a two-step taper shape with the second surface 10 near the edge 3a. The first surface 9 has an inclination angle α with respect to the axis OO and the second surface 10 has an inclination angle β with respect to the axis OO such that α <β. Further, on the air-side inclined surface 6, a large number of protruding ribs 8 are formed at predetermined intervals in the circumferential direction so as to be inclined at a predetermined angle with respect to the tip edge 3a of the seal lip 3. The rib 8 has a chevron cross section. Each rib 8 has a ridge line 11 along the first surface 9 so that the height from the first surface 9 is constant, and the height of the rib 8 depends on the inclination angle α <β. -It becomes gradually lower as it approaches the leading edge 3a of the rulip 3. The height of the rib 8 at the tip edge 3a may be zero. As a result, the height of the tip edge 8a of the rib 8 is relatively lower than that of the other portion 8b.

Next, on the oil-side inclined surface 7, an annular groove 12 formed by a step is formed near the tip edge 3a of the seal lip 3 to weaken the rigidity of the seal lip 3. Furthermore, on the oil-side inclined surface 7, there are a number of projecting cross-sections that extend from the axially starting end edge 12a of the annular groove 12 on the tip edge 3a side of the seal lip 3 to the terminal edge 12b of the annular groove 12. The ribs 13 are formed at the same positions in the axial direction as the ribs 8 formed on the air-side inclined surface 6 at predetermined intervals in the circumferential direction.

FIG. 3 shows another embodiment, in which the oil lip-side inclined surface 7 and the annular groove 12 are formed by forming the oil lip-side inclined surface 7 and the annular groove 12 from the seal lip tip edge 3a toward the oil side. A rib 13 extending from the edge 3a to the terminal edge 12b of the annular groove 12 is formed. Further, FIG. 4 shows another embodiment in which the ribs 13 are formed so as to be displaced in the circumferential direction from the ribs 8 formed on the air-side inclined surface 6. The rib 13 may be formed so as to be parallel to the axis O-O, or may be inclined at a predetermined angle with respect to the tip end edge 3a of the lip. Further, the length of the rib 13 formed on the oil side inclined surface 7 may be from the lip tip edge 3a to the axial end edge 12a of the annular groove 12 as shown in FIG. In addition, the number and shape of the ribs 13 can be set arbitrarily.

[0011]

[Effect of device]

 In the oil seal according to the present invention, since a large number of ribs extending from the lip tip edge to the annular groove are formed on the oil side inclined surface of the seal lip, it is possible to give the lip a reaction force against deformation from the shaft, that is, deformation resistance. In addition, the magnitude of the lip pressure can be clarified, a high pumping action can be maintained, and the sealing performance can be improved by preventing the lip from rising.

[0012]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an oil seal according to an embodiment of the present invention.

FIG. 2 is a perspective view of an enlarged main part of the seal lip of FIG.

3 is a view corresponding to FIG. 2 of another embodiment according to the present invention.

FIG. 4 is a view corresponding to FIG. 2 of still another embodiment according to the present invention.

FIG. 5 is a perspective view of a main part of a conventional oil seal.

FIG. 6 is a view showing a state where the tip edge of the seal lip in FIG. 3 is in contact with the shaft.

FIG. 7 is a sectional view of another conventional oil seal.

[Explanation of symbols]

1a Seal member 3 Seal lip 3a Seal lip tip edge 6 Air side inclined surface 7 Oil side inclined surface 8, 13 Rib 12 Annular groove

Claims (1)

[Reference number] KU020016 [Claims for utility model registration] 1. A rubber seal member formed with an annular seal lip having a wedge-shaped cross section, which is composed of an air-side inclined surface and an oil-side inclined surface which are inclined in opposite directions, and the air-side inclined surface is provided with the above-mentioned rubber seal member. A number of protruding ribs that are inclined with respect to the seal lip tip edge are formed, and the height of the rib from the air side inclined surface at the seal lip tip edge side portion is relatively lower than other portions. In the oil seal thus formed, in which the annular groove is formed at the tip end side of the seal lip of the oil side inclined surface, a large number of protruding ribs are provided at predetermined circumferential intervals in the annular groove of the oil side inclined surface. An oil seal characterized by being formed by forming.