JP4666132B2 - Oil seal - Google Patents

Description

The present invention relates to an oil seal, and more particularly, to an oil seal that has a protrusion provided on an inclined surface of a seal lip portion to push oil back to the sealing target side.

  Conventionally, for example, an oil seal 101 shown in FIG. 3 is known. The oil seal 101 includes a metal ring 102 having an L-shaped cross section and a seal body 103 made of a rubber-like elastic body that is vulcanized and bonded so as to cover the metal ring 102. The seal body 103 is composed of a fixed sealing portion 104 positioned on the outer peripheral side of the metal ring 102 and a seal lip portion 106 positioned on the inner peripheral side of the metal ring 102 and having a lip edge 105 at the tip portion. On the outer peripheral side of the portion 106 and on the opposite side of the lip edge 105, a recess 108 for mounting the garter spring 107 is provided.

The oil seal 101 is disposed between the housing 111 and a shaft 112 that is on the inner peripheral side thereof and concentric with the housing 111, and the metal ring 102 is fixed to the housing 111 via a fixed sealing portion 104. The lip edge 105 which is the tip of the seal lip portion 106 is attached to the shaft 112 so as to be in close contact with the shaft 112 . A garter spring 107 mounted in a recess 108 formed on the opposite side of the lip edge 105 is tightened radially inward, so that the atmosphere-side inclined surface 109 is separated from the lip edge 105 which is the tip of the seal lip portion 106. A predetermined portion slides on the shaft 112 to prevent foreign matter such as muddy water from entering the sealed fluid side A from the atmosphere side B and prevent oil on the sealed fluid side A from flowing out to the atmosphere side B. Yes.

However, in the oil seal 101, since the shaft 112 and the oil seal 101 rotate relative to each other, a small amount of oil leaks to the atmosphere side B from the sliding surface between the seal lip portion 106 and the shaft 112. An oil seal provided with a plurality of protrusions on the atmosphere-side inclined surface 109, that is, a so-called threaded oil seal, is well known for the purpose of pushing the leaked oil back to the sealed fluid side A and enhancing the sealing effect. For example, what is described in Japanese Utility Model Laid-Open No. 2-109076. The threaded oil seal, a plurality of projections provided on the air-side inclined surface of the seal lip portion, since the mounted so as to have a predetermined angle with respect to the circumferential direction, the sealing lip and the shaft peripheral surface A small amount of oil leaking from between the two and the like acts as a pump so as to push it back to the sealed fluid side, thereby further preventing the oil from leaking to the atmosphere side.

However, the protrusion disclosed in the above device has a cross-sectional shape as shown in FIG. 4 and is composed of a pair of inclined side surfaces 121 intersecting each other at an angle γ. In the case of a low viscosity oil, there is a problem that an oil film is not formed between the protrusions 120 and the pump function does not work effectively.

Japanese Utility Model Publication No. 02-109076

The present invention has been made in view of the above points, and an object of the present invention is to provide a threaded oil seal having a high sealing effect that can act as a pump by a protrusion even if the object to be sealed is a low-viscosity oil such as gasoline or light oil. And

In order to achieve the above object, an oil seal according to claim 1 of the present invention provides:
In a circumferential direction on the atmosphere-side inclined surface of the seal lip portion that is integrally formed with the fixed sealing portion that is in close contact with the other member disposed concentrically with the one member and that is provided to slide on the one member. In the oil seal provided with a plurality of protrusions having a fixed inclination angle, the protrusions have two or more inclined side surfaces with different inclination angles, and the inclined side surfaces on both sides of the tip portion are mutually connected. The angle formed is smaller than the angle formed by the inclined side surfaces on both sides on the base side of the projection .

  The present invention has the following effects.

That is, in the oil seal of the present invention having the above-described configuration, the side surfaces on both sides of the protrusion are formed by two or more inclined side surfaces having different inclination angles, and the angle formed by the inclined side surfaces on both sides of the tip portion of the protrusion However, since the inclined side surfaces on both sides on the base side of the projection are smaller than each other, a small amount of the liquid to be sealed leaked from the sliding surface of the seal lip portion and the one member is separated between the one member and the tip of the projection. It becomes easy to be supplied to the narrow gap formed . In addition, since the liquid to be sealed also flows into the protrusion corners due to the inclined surface on the atmosphere side of the seal lip and the inclined side surface on the base side of the protrusion , the supply amount to the root corner increases to form an oil film and pump Since the function can be effectively operated, the sealing effect can be further enhanced.

  Preferred embodiments of the present invention will be described below with reference to the drawings. However, the scope of the present invention is not intended to be limited to the contents described in this embodiment unless otherwise specified.

FIG. 1 shows a cross section of a main part of an oil seal 1 according to an embodiment of the present invention, which is configured as follows.

  The oil seal 1 includes a metal ring 2 having an L-shaped cross section and a seal body 3 made of a rubber-like elastic body that is vulcanized and bonded so as to cover the metal ring 2. The seal body 3 is composed of a fixed sealing portion 4 positioned on the outer peripheral side of the metal ring 2 and a seal lip portion 6 positioned on the inner peripheral side of the metal ring 2 and having a lip edge 5 at the tip. On the outer peripheral side of the portion 6 and on the opposite side of the lip edge 5, a recess 8 for mounting the garter spring 7 is provided.

The oil seal 1 is disposed between a housing 11 and a shaft 12 on the inner peripheral side thereof and concentric with the housing 11. The metal ring 2 is fixed to the housing 11 via a fixed sealing portion 4. The lip edge 5 which is the tip of the seal lip 6 is attached to the shaft 12 so as to be in close contact with the shaft 12 . The garter spring 7 attached to the recess 8 formed on the opposite side of the lip edge 5 is tightened radially inward to improve the sealing performance of the seal lip portion 6, and foreign matters such as muddy water are released from the atmosphere side B. In addition to preventing the oil from entering the sealed fluid side A, the oil on the sealed fluid side A is prevented from leaking out to the atmosphere side B.

Furthermore, a plurality of protrusions 21 are provided on the atmosphere-side inclined surface 9 of the seal lip portion 6 with a predetermined inclination angle with respect to the circumferential direction at a predetermined interval in the circumferential direction . In addition, as shown in FIG. 2, the inclined side surfaces on both sides forming the protrusion 21 are formed by connecting two or more inclined side surfaces 22 and 23 having different inclination angles , and are inclined on both sides of the tip 24 of the protrusion 21. The angle α formed between the side surfaces 22 and 22 is formed to be smaller than the angle β formed between the inclined side surfaces 23 and 23 on both sides on the adjacent base portion 25 side . For example, α is set to 90 ° with respect to β = 130 °.

The oil seal 1 mounted in this way has a sealing property secured by the elasticity of the garter spring 7 and the lip edge 5 of the seal lip 6 is pressed against the shaft 12, but the oil seal 1 and the shaft 12 are relatively Since it rotates, a small amount of oil leaks from the sealed fluid side A to the atmosphere side B from the lip edge 5 which is the tip of the seal lip portion 6. However, the atmosphere side inclined surface 9 of the seal lip 6 is provided with a plurality of projections 21 at a predetermined interval, and the inclined side surfaces on both sides of the projection 21 have two or more inclined side surfaces 22 having different inclination angles. The angle α formed between the inclined side surfaces 22 and 22 on both sides of the tip portion 24 of the protrusion 21 is smaller than the angle β formed between the inclined side surfaces 23 and 23 on both sides on the adjacent base 25 side. Therefore, a small amount of leaked oil can easily flow from the inclined side surface 23 on the base 25 side along the inclined side surface 22 of the distal end portion 24. Therefore, the oil is easily supplied to the narrow gap 31 formed at the tip of the projection 21 with the shaft peripheral surface, and the inclined side surface 9 of the seal lip portion 6 and the inclined side surface 23 of the projection 21 on the base 25 side have a small inclination. The oil supply amount is also increased at the protrusion corner portion 32, so that an oil film can be easily formed, and the pump function can be effectively operated.

  It should be noted that the inclination angle is set to a value where α is smaller than β in accordance with the use conditions in the range of α = 90 to 120 degrees and β = 130 to 160 degrees.

In the present embodiment, the case where there are two types of inclined side surfaces has been described. However, there may be three or more types. With the configuration described above, the sealing fluid is supplied to the narrow gap at the tip of the lip, so that the inclination angle of the third inclined side surface connected to the base 25 side may be any angle.

  The height of the protrusion 21 is appropriately selected within a range in which the liquid to be sealed does not leak when stationary and within a range in which the pump function operates.

Partial sectional view of an oil seal according to the present invention The expanded sectional view of the projection part concerning the present invention Partial sectional view of an oil seal according to a conventional example Enlarged sectional view of a protrusion according to a conventional example

DESCRIPTION OF SYMBOLS 1 Oil seal 2 Metal ring 3 Seal main body 4 Fixed sealing part 5 Lip edge 6 Seal lip part 7 Garter spring 8 Recessed part 9 Atmosphere side inclined surface 11 Housing
12 axes
21 Protrusions
22 Inclined side
23 Base side inclined side surface 24 Tip 25 Base 31 Narrow gap 32 Base corner
Angle formed by the inclined side surfaces on both sides of α and β

Claims (1)

In a circumferential direction on the atmosphere-side inclined surface of the seal lip portion that is integrally formed with the fixed sealing portion that is in close contact with the other member disposed concentrically with the one member and that is provided to slide on the one member. In the oil seal provided with a plurality of protrusions having a fixed inclination angle ,
The side surface of each side of the protrusion is composed of two or more inclined side surfaces having different inclination angles, and the angle formed by the inclined side surfaces on both sides of the tip portion is greater than the angle formed by the inclined side surfaces on both sides on the base side of the protrusion An oil seal that is small .

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