JPH0643579Y2 - Oil seal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an oil seal used for sealing between two members that are concentrically combined with each other and make relative rotational movement, and more specifically, A combination of a wear sleeve having a substantially L-shaped cross-sectional shape attached to a shaft, and a seal member having a rubber-like elastic material seal lip that is fitted into a housing and slidably slides on a cylindrical peripheral surface of the wear sleeve. Related to the oil seal.

[Prior Art] As shown in FIG. 4, a wear member (2) having a substantially L-shaped cross section is attached to a rotating shaft, and a seal member having a seal lip made of a rubber-like elastic material. There is known an oil seal in which (6) is mounted on the housing side and the seal lip is brought into sealing contact with the peripheral surface of the wear sleeve.

In the oil seal of the same figure, the wear sleeve (2) has a cylindrical portion (3) provided with a coating of a rubber-like elastic material on the inner peripheral side, and a flange portion radially extending from one end of the cylindrical portion (3). (4) is attached to the shaft (1). Further, the seal member (6) is a held portion (7) made of an annular body having a substantially V-shaped cross section.
And a seal lip adhered to the inner end of the held portion (7). Then, the seal member (6) is attached to the housing (5), and the seal lip (8) is slidably slid on the peripheral surface of the cylindrical portion (3) of the wear sleeve (2). Furthermore, the held portion (7) of the seal member (6)
Wear sleeve (2) with a donut shape at the end
A unitizing plate (10) is provided so as to face the flange portion (4) of the.

The oil seal described above is provided on the side surface of the held portion (7) of the flange portion (4) of the wear sleeve (2) attached to the shaft (1) and the end portion of the held portion (7). It is sandwiched between the provided unitizing plates and regulates the relative position of the wear sleeve (10) and the seal member (6) in the axial direction, and is formed between the flange portion (4) and the unitizing plate (10). The labyrinth effect of the small gap is achieved.

Further, the seal lip (8) provided on the seal member (6) is configured to prevent leakage of the internal lubricant and intrusion of dust, muddy water, and the like from the outside.

[Problems to be Solved by the Invention] In the oil seal described above, in order to ensure the function of preventing the intrusion of external dust and the like, the oil seal is formed between the flange portion (4) and the unitizing plate (10). It is effective to set the gap formed as narrow as possible to enhance the labyrinth effect of the gap. However, the smaller the gap is, the more axial positioning of the wear sleeve (2) and the seal member (6) becomes. Not only is it difficult to perform, but there is also a large risk of increasing friction loss due to contact between the flange portion (4) and the unitizing plate (10) due to fluctuations in the relative positions of the shaft (1) and housing (5) during operation. .

There is also an example in which the flange portion (4) or the side faces of the unitizing plate (10) are provided with at least one dust lip that is slidably sealed on the facing faces, but in this case also, the wear sleeve (2) and the unitizing plate ( This is not preferable because friction loss with 10) increases.

On the other hand, the flange portion (4) of the wear sleeve (2) extends radially outward from the cylindrical portion (3), and the seal member (6).
Of the wear sleeve (2) because the unitized plate (10), which is connected to the held portion (7) of the wearer and faces the flange portion (4), extends radially inward from the held portion (7). Due to the centrifugal force caused by the above, external dust or the like that enters through the gap formed between the flange portion (4) and the unitized plate reaches the seal lip (8) side, and the seal lip (8) early May cause wear.

The present invention provides a structure of an oil seal that solves the above-mentioned problems in the conventional oil seal, suppresses friction loss due to rotation, and reliably prevents external dust and the like from entering due to centrifugal force. That is the purpose.

[Means for Solving the Problems] In view of the above points, the present invention has a held portion that has an outer peripheral cylindrical portion attached to a housing and a radial portion that extends radially inward from one axial end of the outer peripheral cylindrical portion. And a seal member composed of a seal lip made of a rubber-like elastic material adhered to the inner peripheral end of the radial portion, and a cylindrical portion mounted on a shaft rotating relative to the housing and sliding on the seal lip. A wear sleeve having a substantially L-shaped cross-section, the wear sleeve having a flange portion extending from the cylindrical portion in a radial direction,
An oil seal having a substantially donut shape at the other end of the outer peripheral cylindrical portion, which is joined to a unitized plate that forms a gap in the radial direction in a state of facing the flange portion, in the outer peripheral end portion of the flange portion. An auxiliary seal made of a rubber-like elastic material is adhered to the inner peripheral surface of the outer peripheral cylindrical portion, and a substantially screw-shaped protrusion or groove is formed on the outer peripheral surface of the auxiliary seal to provide a hydrodynamic pump action toward the unitized plate side. At the same time, a drain hole is formed at the radially outer end of the unitize plate.

The auxiliary seal made of a substantially cylindrical rubber-like elastic material adhered to the outer end of the flange of the wear sleeve is designed to keep the foreign matter environment level and the rotation speed between the inner peripheral surface of the held portion and the opposite surface. Correspondingly, zero or a slight tightening margin is set.

The auxiliary seal is expanded outward by the centrifugal force caused by the rotation of the wear sleeve and strongly contacts the inner peripheral surface of the held portion to generate heat, so in high-speed rotation where heat generation becomes a problem,
The design of the appropriate hardness to withstand the centrifugal forces at maximum rotation controls the movement of the auxiliary seal.

At low rotational speeds, hydrodynamic labyrinth seals are formed, and at high rotational speeds very slight contact (minimum lip load designed to reduce heat generation in the auxiliary seal) is desirable in some foreign body environments.

A hydrodynamic labyrinth type that eliminates foreign substances by utilizing a considerable protrusion height or groove depth when the auxiliary seal wears and eliminates the interference when using the contact design at high speed. The sealing function of can be maintained.

When used in a device with a rotating housing, a slight interference or minimal clearance is applied to obtain a similar improved sealing function, since no centrifugal force acts on the auxiliary seal.

[Operation] According to the oil seal of the present invention, a gap is formed between the flange portion (4) and the unitizing plate (10), and dust passing through the gap passes over the flange portion (4) and the seal lip ( In order to prevent reaching to 8), an auxiliary seal (12) is provided and the auxiliary seal (12) is provided with a substantially screw-shaped projection or groove (13) that causes a hydrodynamic pumping action toward the unitizing plate (10) side. It is attached.

Due to this pumping action, a substantially screw-shaped protrusion or groove (13)
Dust and the like located in the vicinity of are pushed back to the unitizing plate (10) side when the shaft rotates. But unitized boards (10)
In the gap (16) between the flange (4) and the unitizing plate (1
Dust that has entered from the inner peripheral surface of (0) is in the flange (4).
Because of the centrifugal force generated by the rotation of the gap, a flow moving in the outer peripheral direction is formed, so that dust and the like that have entered through the gap (16) cannot exit from the inner peripheral end portion of the unitized plate in the gap. Therefore, by providing a drain hole (11) at the radial outer end of the unitizing plate (10) for dust and the like collected in the oil seal, the oil seal can be utilized by utilizing the pump action generated by the auxiliary seal (12). It is possible to effectively discharge dust and the like that is trying to accumulate inside.

As described above, the oil seal of the present invention has improved sealability, and a good seal can be obtained without minimizing the gap between the conventional flange portion and the unitized plate. The gap may be set relatively large, that is, the axial positioning accuracy between the seal member and the wear ring is not required.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings. In the embodiment shown in FIG. 1, an outer peripheral cylindrical portion to be attached to a housing (5) and a radial inner side from one axial end of the outer peripheral cylindrical portion. A seal member (6) having a held portion (7) having a radial portion extending in the direction of the radial direction and having a seal lip (8) made of a rubber-like elastic material adhered to the inner peripheral end of the radial portion. And have. Further, a cylindrical portion (3) mounted on a shaft (1) that rotates relative to the housing (5) and on which the seal lip (8) slides, and a flange portion (radially extending from the cylindrical portion (3) ( 4) and a wear sleeve (2) having a substantially L-shaped cross section having a substantially donut shape at the other end of the outer peripheral cylindrical portion, and having a gap in the radial direction facing the flange portion (4). Bonded unitizing plates (10) forming (16).

A rubber-like elastic material auxiliary seal (12) facing the inner peripheral surface of the outer peripheral cylindrical portion is adhered to the outer peripheral end of the flange portion (4), and the unitized plate (10) is attached to the outer peripheral surface of the auxiliary seal (12). ) Side is formed with a substantially screw-shaped projection or groove (13) for providing a hydrodynamic pumping action, and a drain hole (11) is formed at the radially outer end of the unitizing plate (10).

In the embodiment described above, the threaded groove (13) formed on the peripheral surface of the auxiliary seal (12) causes a hydrodynamic pumping action by rotation of the wear sleeve (2) attached to the shaft (1). Show. Dite and muddy water that have flowed in between the flange portion (4) and the unitizing plate (10) cannot be drained (1).
It is excluded to the outside through 1).

In the second embodiment, the outer end portion of the flange portion (4) is bent toward the cylindrical portion (3) side so that the rubber-like elastic material auxiliary seal (1
The point 2) is directed to the unitizing plate (10) side, which is different from the embodiment shown in FIG. In the embodiment shown in FIG. 3, in addition to the auxiliary seal (12) and the drain hole (11) in the embodiment shown in FIG. 1, a wear sleeve (4) is formed on the side surface of the flange portion (4) facing the unitizing plate (10). A spiral groove (14) that provides a hydrodynamic pumping action from the outside to the inside with the rotation of 2) is provided, and an annular protrusion () is provided at the end of the auxiliary seal (12) on the unitizing plate (10) side. 15) is provided to strengthen the function of blocking the intrusion of dust or muddy water.

[Advantages of the Invention] As described above, the oil seal of the present invention includes a retained portion having an outer peripheral cylindrical portion attached to the housing and a radial portion extending radially inward from one axial end of the outer peripheral cylindrical portion, A seal member composed of a seal lip made of a rubber-like elastic material adhered to an inner peripheral end of the radial portion, a cylindrical portion attached to a shaft rotating relative to a housing, and sliding with the seal lip, and A wear sleeve having a substantially L-shaped cross section having a flange portion extending in the radial direction from the cylindrical portion is provided, and the other end portion of the outer peripheral cylindrical portion has a substantially donut shape, and is in a radial direction in a state of facing the flange portion. In an oil seal to which a unitized plate forming a gap is connected, an auxiliary seal made of rubber-like elastic material facing the inner peripheral surface of the outer peripheral cylindrical portion is provided at the outer peripheral end of the flange portion. Is attached to the outer surface of the auxiliary seal, and a substantially screw-shaped projection or groove for providing a hydrodynamic pumping action toward the unitized plate is formed, and a drain hole is formed at the outer end of the unitized plate in the radial direction. The following effects are achieved by adopting the configuration in which it is leaned.

The accuracy of the axial position when assembling the wear sleeve and the seal member is not required, and the hydrodynamic pumping action produced by the protrusions or grooves of the auxiliary seal as the wear sleeve rotates causes the flange portion and the unitized plate to move. Dust that has passed through the space is removed to the outside through the drain hole of the unitizing plate, so damage to the seal lip due to dust or muddy water is effectively prevented.

[Brief description of drawings]

FIG. 1 is a half-cut sectional view according to an embodiment of the present invention, FIGS. 2 and 3 are half-cut sectional views according to other embodiments of the present invention, and FIG. 4 is a half-cut sectional view of a conventional technique. (1) …… Shaft, (2) …… Wear sleeve,
(3) …… Cylinder part, (4) …… Flange part, (5) ……
Housing, (6) …… Seal member, (7) …… Retained part, (8) …… Seal lip, (10) …… Unitize plate, (11) …… Drain hole, (12) …… Auxiliary seal , (1
3) …… Screw-like projection or groove, (14) …… Spiral groove, (1
5) …… annular protrusion, (16) …… gap

Claims (1)

[Scope of utility model registration request] 1. A retained portion (7) having an outer peripheral cylindrical portion attached to a housing (5) and a radial portion extending radially inward from one axial end of the outer peripheral cylindrical portion, and a retained portion (7) of the radial portion. A seal member (6) composed of a seal lip (8) made of a rubber-like elastic material adhered to an inner peripheral end, and a shaft (1) rotating relative to a housing (5) are attached to the seal lip (8). 8) Sliding cylindrical part (3)
And a wear sleeve (2) having a substantially L-shaped cross section having a flange portion (4) extending from the cylindrical portion (3) in the radial direction.
An oil having a substantially donut shape at the other end of the outer peripheral cylindrical portion and having a unitary plate (10) which forms a gap (16) in the radial direction in a state of facing the flange portion (4). In the seal, a rubber-like elastic material auxiliary seal (12) facing the inner peripheral surface of the outer peripheral cylindrical portion is adhered to the outer peripheral end of the flange portion (4), and the outer peripheral surface of the auxiliary seal (12) has the above-mentioned structure. A substantially screw-shaped projection or groove (13) for providing a hydrodynamic pumping action toward the unitizing plate (10) side is formed, and a drain hole (11) is formed at the radially outer end of the unitizing plate (10). An oil seal characterized by being dripping.