JP2571439Y2 - Universal joint sealing device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device for a universal joint in which leakage of lubricating oil from an oil seal is improved.

[0002]

2. Description of the Related Art Conventionally, for example, an output shaft and a propeller shaft of a transmission of an automobile are connected by a universal joint.

Specifically, as shown in FIG. 2, the universal joint includes a yoke bearing case 1a fixed to an end of an output shaft and a yoke bearing case fixed to an end of a propeller shaft. 1b, 1
b are connected by a cross shaft 3. A rolling element 4 is disposed between the shaft end 3a of the cross shaft 3 and the bearing case 1 (1a, 1b) (see Japanese Utility Model Laid-Open No. 63-49026).

The open end 1 d of the bearing case 1 is sealed by a seal member 5.

[0005] As shown in detail in FIG. 3, the seal member 5 includes a cored bar 6 and an oil seal 7 supported by the cored bar 6. The metal core 6 is pressed into a concave step portion 1c formed at the opening end 1d of the bearing case 1. The oil seal 7 faces the outer side of the bearing case 1, and has a first lip portion 7 a slidably in contact with an outer peripheral surface of the slinger 8 pressed into the base 3 b of the cross shaft 3, and a shaft of the cross shaft 3. A second lip portion 7b slidingly contacting the outer peripheral surface of the end portion 3a.

[0006]

However, the lips 7a, 7b of the oil seal 7 are all directed outward of the bearing case 1. Therefore, as shown in FIG. 2, each lip portion 7a, 7b responds to the pressure of the lubricating oil supplied from the lubricating oil supply hole 3c of the cross shaft 3 to the rotating portion of the rolling element 4 by centrifugal force. Become an escaper. Therefore, when the universal joint rotates, the gap between the second lip 7b and the outer peripheral surface of the shaft end 3a of the cross shaft 3 and the gap between the first lip 7a and the outer peripheral surface of the slinger 8 are determined. Therefore, there is a problem that the lubricating oil easily leaks to the outside.

[0007] This problem is an important problem that must be overcome in order to satisfy the recent demand for extending the greasing interval inside the bearing, and at least the demand for maintenance-free operation during the overhaul period.

[0008] Therefore, the object of the present invention is to provide a universal joint in which the structure of the seal member is devised so that lubricating oil does not easily leak from the oil seal and foreign substances do not enter from the outside, in order to achieve maintenance-free operation. To provide a sealing device.

[0009]

In order to achieve the above object, according to the present invention, a rolling element is disposed between a bearing case of a yoke and a shaft end of a cross shaft, and the opening end of the bearing case is sealed. In the sealing device for a universal joint provided with a sealing member, a slinger having a substantially U-shaped cross section which is fitted to the base of the cross shaft with an opening facing the opening end of the bearing case, and an opening of the bearing case A seal member attached to the end, the seal member comprising a metal core and an oil seal, wherein the metal core is press-fitted into a concave step formed at an open end of the bearing case; A supporting portion that supports the oil seal, and a pressing portion that presses an end surface of the rolling element, wherein the oil seal has
A first lip projecting inwardly of the bearing case and slidingly contacting an outer peripheral surface of a shaft end of the cross shaft;
A second portion extending in the axial direction opposite to the lip and slidingly contacting a curved portion of the cross shaft formed between the shaft end portion and the root portion of the cross shaft;
A third lip extending diagonally inward in the slinger direction from the support portion of the cored bar in a radially inward direction, and slidingly contacting the outer peripheral surface of the inner leg portion of the slinger; A fourth portion is formed so as to extend diagonally outward in the radial direction continuously from the portion, and slides on the inner surface of the bottom of the slinger.
And a fifth lip that protrudes toward the opening end face of the bearing case near the opening on the inner peripheral surface of the outer leg portion of the slinger.

[0010]

When the slinger and the seal member having the above construction are assembled at a predetermined position of the universal joint, the sealing device operates as follows.

[0011] The end face of the rolling element is pressed by the pressing portion of the metal core pressed into the concave step portion of the bearing case, and the axial movement of the rolling element is regulated.

Since the first lip portion of the oil seal faces the holding portion of the core metal, that is, the inside of the bearing case, the first lip portion bites against the pressure of the lubricating oil supplied to the rotating portion of the rolling element. As a result, the pressure of the lubricating oil makes it possible to strongly press the outer peripheral surface of the shaft end of the cross shaft. Therefore, outflow of lubricating oil is prevented. In this specification, the term lubricating oil includes grease.

Further, since the fifth lip of the oil seal projects toward the opening end of the bearing case, that is, toward the outside of the slinger, the fifth lip easily penetrates into the outside air pressure, so that the outer leg portion of the slinger can be easily inserted. It is strongly pressed against the inner peripheral surface. Therefore, invasion of foreign substances such as muddy water and dust into the slinger is prevented. Also, like the fifth lip,
The fourth, third, and second lips are also self-penetrating due to the outside air pressure due to the protruding direction of each lip, and are strongly pressed against the bottom of the slinger, the inner leg of the slinger, and the curved portion of the cross shaft, respectively. Can be Therefore, even if foreign matter enters the slinger from outside from between the fifth lip and the outer leg of the slinger, the remaining fourth, third,
The second lip sequentially prevents foreign matter from entering. In addition, since the sealing performance is maintained by the fourth lip against the axial displacement between the bearing case and the cross shaft that occurs during operation, the effect of preventing foreign matter from entering is maintained for a long time.

Further, among the first to fifth lips, the lips adjacent to each other are located at positions separated from each other in the axial direction and the radial direction, so that a space is formed therebetween, and lubricating oil is sealed in this space. Thereby, the durability of the lip itself is improved.

Further, among the above five lips, the third to fifth lips are provided.
Since the lip is provided inside the above slinger,
This effectively utilizes the internal space of the slinger, and even with such a large number of lips, the device can be effectively sealed with a small space without increasing the size of the device.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in FIG.

The same construction as the prior art shown in FIG.
The parts of the operation are assigned the same numbers, and detailed explanations are omitted.

As shown in FIG. 1, a rolling element 4 is disposed between the shaft end 3a of the cross shaft 3 of the universal joint and the bearing case 1 of the yoke. This bearing case 1
A concave step portion 1c is formed at the open end 1d of the first member.

On the outer peripheral surface of the root 3d of the cross shaft 3,
A substantially U-shaped slinger 10 opened toward the open end 1d of the bearing case 1 is press-fitted.

On the other hand, the seal member 11 comprises a cored bar 12 and an oil seal 13.

The cored bar 12 has a press-fit portion 12a which is an overlapped portion in which the outer peripheral surface is press-fitted from the axial direction to the inner peripheral surface of the concave step portion 1c of the bearing case 1, and this press-fit. A support portion 12b that protrudes from the portion 12a in a radially inward / outward direction in a flange shape, is insert-molded into the oil seal 13, and supports the oil seal 13;
A pressing portion 12c that is integrated with the inner peripheral surface of the press-fit portion 12a by press-fit and that presses the end surface 4a of the rolling element 4 is provided.

The pressing portion 12c does not need to be integrated with the cored bar 12, for example, the concave step portion 1 of the bearing case 1.
A ring-shaped flat plate may be sandwiched between the bottom surface of c and the press-fit portion 12a of the cored bar 12, and the flat plate may press the end surface 4a of the rolling element 4.

On the other hand, the oil seal 13 has the following five types of lips. That is, (1) the inner side of the bearing case 1, that is, the holding portion 1
A lubricating oil outflow prevention lip 13a as a first lip that protrudes toward 2c and slides on the outer peripheral surface of the shaft end 3a of the cross shaft 3. A ring-shaped coil spring 14 for biasing the lip 13a in the radial direction is insert-molded on the lubricating oil outflow prevention lip 13a.

The lip 13a for preventing lubricating oil from flowing out
Is in the position of the solid line in the free state, but displaces as shown by the two-dot chain line in the state where it is incorporated in a predetermined place. This is also true for the remaining four lips.

(2) The lubricating oil outflow prevention lip 13
The second lip extends in the direction opposite to the axial direction of "a", that is, the outer side of the bearing case 1, and slides on the curved portion 3d formed between the shaft end 3a and the root 3b of the cross shaft 3. Axial lip 13c.

(3) A third lip extending from the outer flange-shaped support portion 12b of the cored bar 12 to the inside of the slinger 10 obliquely in the radial direction and slidingly contacting the outer peripheral surface of the inner leg portion 10a of the slinger 10. Main radial lip 13b for preventing foreign matter from entering.

(4) A main axial lip as a fourth lip extending obliquely outward in the radial direction from the main radial lip 13b toward the bottom 10c of the slinger 10 and slidingly contacting the inner surface of the bottom 10c. 13
f. The main axial lip 13f is formed continuously from the main radial lip 13b, as is apparent from FIG.

(5) Opening-side end face 1e of the bearing case 1
To the outer leg 10b of the slinger 10.
And a lip 13e for preventing foreign matter from entering as a fifth lip that is in sliding contact with the inner peripheral surface of the lip 13e. Due to the sealing action of the lip 13e, foreign substances such as muddy water and dust are removed from the slinger 10.
Intrusion into the inside is prevented. This lip 13
It is not necessary for e to be in contact with the slinger 10, and in the case of non-contact, the labyrinth structure may be provided between the slinger 10 and the outer leg 10b.

The five lips provided on the oil seal 13 have been described above. Of the five lips, three lips 13e, 13f, and 13b are provided inside the slinger 10 to effectively use the internal space of the slinger 10. Because I used it, despite forming many lips,
An effective sealing structure can be provided without increasing the size of the sealing device.

Of the above five lips, lips 13a and 13c, 13c and 13b, 13b and 13
f, the space formed between 13f and 13e,
Lubricant is enclosed to improve the durability of the lip itself, and thus maintain the sealing performance for a long period of time.

The oil seal 13 is provided with a bulging portion 13d which comes into contact with the opening side end face 1e of the bearing case 1 and is displaced from a solid line state to a two-dot chain line state.

According to the above configuration, most of the rainwater and the like from the outside is first bounced off by the slinger 10, but the rainwater that has entered the gap between the end face 1 e of the bearing case 1 and the outer leg 10 b of the slinger 10. Foreign matter such as is prevented from entering the opening end 1d side of the bearing case 1 by the bulging portion 13d of the oil seal 13, and is prevented from entering the slinger 10 by the lip 13e.

Further, the main axial and radial lips 13f and 13b are apt to bite against the external air pressure, and are strongly pressed against the inner surface of the bottom portion 10c of the slinger 10 and the outer peripheral surface of the inner leg 10a by the external air pressure. Rainwater or the like that has entered the inside 10 is prevented from entering the curved portion 3d side of the cross shaft 3 by the main axial and the radial lips 13f and 13b.

In the event that foreign matter enters the curved portion 3d, the axial lip 13c slidingly contacting the curved portion 3d prevents entry into the bearing.

As described above, according to the present invention, foreign matter intrusion is prevented in four steps by the foreign matter intrusion prevention lips 13e, 13f, 13b, and 13c which are sequentially provided at a predetermined distance from the outside to the inside in the radial direction. Is prevented. Therefore, intrusion of foreign matter into the bearing is very effectively prevented. In addition, with respect to the axial displacement between the bearing case 1 and the cross shaft 3 that occurs during operation, the sealing performance is maintained by the main axial lip 13f that is in sliding contact with the bottom 3c of the slinger 10, so that the sealing performance is maintained for a long time. The effect of preventing foreign matter from entering is maintained.

On the other hand, the lubricating oil outflow preventing lip portion 13a
Is directed inwardly of the bearing case 1, so that it easily penetrates the pressure of the lubricating oil supplied to the rotating portion of the rolling element 4, and the pressure of the lubricating oil and the urging force of the coil spring 14 At the outer peripheral surface of the shaft end 3a of the cross shaft 3, the lubricating oil hardly leaks to the outside through the gap between the lip 13a and the outer peripheral surface of the shaft end 3a of the cross shaft 3. In addition, entry of foreign matter is also prevented.

[0037]

As is apparent from the above description, the sealing device for a universal joint according to the present invention has a U-shaped cross-section in which the opening is opposed to the opening end of the bearing case and pressed into the base of the cross shaft. A slinger and a seal member attached to the open end of the bearing case are provided. The oil seal is supported by a metal core pressed into a concave step formed at the open end of the bearing case. A lip is provided. Of these five lips, the first lip projects toward the inner side of the bearing case, so that the first lip penetrates against the pressure of the lubricating oil supplied to the rotating portion of the rolling element, and the lubricating oil Since the pressure is strongly pressed against the outer peripheral surface of the shaft end of the cross shaft, it is possible to prevent the lubricating oil from leaking outside through the space between the first lip and the outer peripheral surface of the shaft end of the cross shaft. it can. Further, among the remaining four lips, the fifth lip projects toward the opening-side end surface of the bearing case, that is, toward the outside of the slinger, so that the fifth lip penetrates into the outside air pressure and becomes selfish. It is strongly pressed against the inner peripheral surface of the outer leg. Therefore, it is possible to prevent foreign substances such as muddy water and dust from entering the slinger. Also, like the fifth lip, the fourth, third and second lips are also self-penetrating to the external pressure thanks to the direction in which each lip extends, and the bottom of the slinger, the inner leg of the slinger, And the curved part of the cross shaft, respectively, even if foreign matter enters the slinger from outside,
The fourth, third, and second lips can sequentially prevent foreign matter from entering the bearing. In addition, since the sealing property is maintained by the fourth lip against the axial displacement between the bearing case and the cross shaft generated during operation,
The effect of preventing foreign matter from entering can be maintained for a long period of time.

Further, among the first to fifth lips, the lips adjacent to each other are located at positions separated from each other in the axial direction and the radial direction, so that a space is formed therebetween, and lubricating oil is sealed in this space. Thereby, the durability of the lip itself can be improved. Therefore, the sealing properties of each lip can be maintained for a long time.

As described above, the present invention can prevent the lubricating oil from flowing out of the bearing and the intrusion of foreign matter from the outside into the bearing, and can also improve the durability of the lip itself. And can greatly contribute to realization of maintenance-free operation.

Further, among the above five lips, the third to fifth lips
Since the lip is provided inside the slinger, the inner space of the slinger is effectively used, and even with such a large number of lips, the device does not increase in size,
Effective sealing can be achieved with a small space.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a sealing device for a universal joint according to the present invention.

FIG. 2 is a partial cross-sectional plan view of a universal joint.

FIG. 3 is a sectional view of a conventional sealing device for a universal joint.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Bearing case, 1c ... Concave step part, 1d ... Open end, 3 ... Cross axis, 3a ... Shaft end part, 3b ... Root part, 3d ... Curved part, 4
... rolling element, 10 ... slinger, 10a ... inner leg, 10b
... Outer leg part, 10c ... Bottom part, 11 ... Seal member, 12 ... Core bar, 12a ... Press fitting part, 12b ... Support part, 12c ... Holding part, 13 ... Oil seal, 13a ... First lip, 13
b: third lip, 13c: second lip, 13e: fifth lip, 13f: fourth lip.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shunichi Matsui 3-5-8 Minamisenba, Chuo-ku, Osaka-shi, Osaka Inside Koyo Seiko Co., Ltd. (56) References JP-A-57-54725 (JP, A) Showa 54-8045 (JP, U) Actually open Showa 63-49026 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A universal joint sealing device in which a rolling element is disposed between a bearing case of a yoke and a shaft end of a cross shaft, and a sealing member for sealing an opening end of the bearing case is provided. A slinger having a substantially U-shaped cross-section, which is pressed against the root of the cross shaft so as to face the open end of the bearing case, and a seal member attached to the open end of the bearing case. A metal core and an oil seal, wherein the metal core has a press-fit portion that is press-fitted into a concave step formed at an open end of the bearing case, a support portion that supports the oil seal, A first holding portion for holding an end surface, wherein the oil seal projects toward an inner side of the bearing case and slides on an outer peripheral surface of a shaft end of the cross shaft.
A second lip extending in a direction axially opposite to the first lip and slidingly contacting a curved portion of the cross shaft formed between a shaft end portion and a root portion of the cross shaft; A third lip extending radially inward in the slinger from the support portion of the slinger in the radial direction and slidingly contacting the outer peripheral surface of the inner leg of the slinger; and a radial direction continuing from a part of the third lip. A fourth lip formed so as to extend obliquely outward and slidingly contacting the bottom inner surface of the slinger; and a fourth lip projecting toward an opening end surface of the bearing case near an opening of an inner peripheral surface of an outer leg portion of the slinger. 5. A sealing device for a universal joint, comprising: