JPH0649973Y2 - Oil seal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an oil seal for sealing between a housing and a rotary shaft by a slinger and a seal member.

(Prior Art) Conventionally, there is such an oil seal as shown in FIG. The oil seal 100 is configured by attaching a slinger 102 to the outer circumference of a rotating shaft 101. The slinger 102 has a portion fixed to the rotating shaft 101, that is, a cylindrical portion 102a, and further has an annular collar portion 102b extending from the cylindrical portion 102a in the radial direction.

On the other hand, the seal member 104 is provided in the mounting hole 103a of the housing 103.
Are fitted. The seal member 104 is formed integrally with the metal ring 105. Furthermore, a lip portion 106 is formed on the seal member 104, and a lip tip 106a of the lip portion 106 is
The slinger 102 is adapted to be in line contact with the outer peripheral surface in a state of being inclined with respect to the annular flange member 102b by the elastic force in the axial direction as shown by a dotted line so as to seal.

(Problems to be Solved by the Invention) However, in the above-described conventional example, the lip portion 106 slidingly contacting the slinger 102 is deformed by the radial back pressure (arrow a) of the sealing fluid R, and is indicated by the solid line. It will be in a surface contact state. As a result, there is a problem that the lip tip 106a is heated and worn by the frictional force during rotation, the sealing performance is deteriorated, and the sealing fluid R leaks to the atmosphere A side.

This invention is to solve the above problems, and provides an oil seal that prevents the lip from deforming and making surface contact with the slinger due to radial back pressure due to the sealing fluid, and can always maintain stable sealing performance. The purpose is to do.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a rotary shaft by a slinger fixed to an outer peripheral surface of a rotary shaft and an annular seal member having a lip portion slidingly contacting the slinger. In an oil seal formed by hermetically sealing with a housing, the seal member is housed in a fixed case provided in a mounting hole of the housing so as to be movable in the axial direction, and a lip portion is formed in a wedge shape in cross section, In addition, a pressure adjusting chamber that expands by the pressure of the introduced fluid and presses the sealing member toward the slinger is provided between the back surface of the sealing member and the fixed case.

(Operation) According to the operation of the present invention based on the above configuration, the pressure adjusting chamber is expanded by the pressure of the introduced fluid, and the seal member is pressed toward the slinger. As a result, the contact pressure at the lip portion becomes stronger. Therefore, even if the radial pressure by the sealing fluid acts on the lip portion, it does not deform.

(Embodiment) Next, this invention will be described based on an embodiment shown in FIGS. 1 and 2.

FIG. 1 shows the first embodiment, and in the figure, 1 shows the entire oil seal that seals between the mounting hole 3 of the housing 2 and the rotary shaft 4. Reference numeral 5 denotes a fixed case having a U-shaped cross section fitted in the mounting hole 3 via a rubber-like elastic body 6. The fixed case 5 is made of metal, and its open side 7 faces the sealed fluid B. There is. Further, 9 is a rotary shaft 4
With a slinger attached to the outer periphery of via a rubber-like elastic body 8,
The slinger 9 is composed of a cylindrical portion 10 and an annular collar portion 11 extending outward from the cylindrical portion 10.

Reference numeral 12 is a rubber seal member mounted in the fixed case 5 so as to be movable in the axial direction. A lip portion 13 having a wedge-shaped cross section is formed at an end portion of the seal member 12 on the side of the sealed fluid B. Is in sliding contact with the annular brim portion 11. Further, the outer peripheral surface of the seal member 12 is formed with auxiliary lips 14 and 15 which make sealing contact with the inner peripheral surface 5a of the fixed case 5, and the inner peripheral surface is also sealed to the inner peripheral surface 5a of the fixed case 5. An auxiliary lip 16 is formed for contact. Further, on the inner peripheral surface of the seal member 12 and at a position closer to the sealing fluid B side than the auxiliary lip 16, there are formed ridges 17 and 18 which come into contact with the inner peripheral surface 5a of the fixed case 5. The ridges 17 and 18 are for positioning in the fixed case 5 and for maintaining the contact angle and the tip angle of the lip tip 13a of the lip portion 13 with respect to the slinger 9 at predetermined values. Although not particularly shown, an auxiliary lip
Grease for lubrication is enclosed between 14, 15 and between the ridges 17, 18 and the auxiliary lip 16.

Reference numeral 19 denotes the rear surface 20 of the seal member 12 on the atmosphere D side, and the fixed case 5.
A pressure adjusting chamber formed between the inner peripheral surface 5a and the inner peripheral surface 5a for adjusting the back pressure in the axial direction with respect to the seal member 12 by the supply amount of liquid (air, oil, etc.). Reference numeral 21 denotes a fluid supply port that penetrates the fixed case 5 from the pressure adjustment chamber 19 toward the atmosphere D, and is connected to a hydraulic pump, an air compressor or the like (not shown). Reference numeral 22 is a retainer that holds the fluid supply port 21.

Next, the operation of the above embodiment will be described.

First, during rotation of the rotary shaft 4, the mounting hole 3 of the housing 2 and the fixed case 5 are sealed by a rubber-like elastic body 6, and the rotary shaft 4 and the slinger 9 are surrounded by the rubber-like elastic body. 8
It is sealed by. Further, the lip tip 13a of the seal member 12 mounted in the fixed case 5 linearly contacts the annular flange portion 11 of the slinger 9 to seal the sealing fluid B from leaking to the atmosphere D. Furthermore, since the auxiliary lip 14 of the seal member 12 is in contact with the inner peripheral surface of the fixed case 5, the sealing fluid B does not enter the pressure adjusting chamber 19. Furthermore, the protrusions 17 and 18 suppress the eccentricity of the seal member 12.

When a back pressure in the radial direction (arrow b) acts on the lip portion 13 from the sealed fluid B side, compressed air or oil is supplied to the fluid supply port by operating an air compressor and a hydraulic pump (not shown). It is supplied into the pressure control chamber 19 through 21. Then, since the pressure adjusting chamber 19 is sealed by the auxiliary lips 15 and 16, the pressure increases, and the seal member 12 is axially pressed toward the sealed fluid B side. As a result, the lip tip 13a of the lip portion 13 makes strong contact with the annular collar portion 11, so that the lip portion 13 is not deformed, and a good line contact state can be maintained. Therefore, the sealing fluid B does not leak from the sealing surface to the atmosphere D side.

During the above-mentioned operation, the pressure in the pressure control chamber 19 can be changed to correspond to the pressure-generating sealed fluid by appropriately changing it according to the pressure generated from the sealing fluid B side.

FIG. 2 shows a second embodiment. In this embodiment, a plurality of lip portions 13 are formed on the sealing fluid B side of the seal member 12. And between the lip portions 13,
The same grease (not shown) as described above is filled. The lip portion 13 is not limited to three places as in the illustrated embodiment.
The configuration of the other parts is the same as that of the above-mentioned embodiment, and therefore will be omitted.

The operation is the same as that of the above-described embodiment, but there are a plurality of lip portions 13 in contact with the annular flange portion 11 of the slinger 9, and the grease is filled to improve heat resistance and wear resistance.

In addition, in the first and second embodiments, the seal member 12
As a matter of course, a material having excellent oil resistance, heat resistance, and wear resistance such as nitrile rubber, acrylic rubber, silicone rubber, and fluorine rubber is selected.

(Effect of the Invention) Since the present invention is configured as described above, the pressure adjusting chamber expands and presses the seal member due to the pressure of the introduced fluid, thereby increasing the contact pressure of the lip tip with respect to the slinger. be able to. Therefore, it is possible to prevent the lip portion from being deformed due to the radial pressure of the sealing fluid to cause heat generation and wear of the lip tip, and it is possible to maintain a stable sealing performance at all times.

[Brief description of drawings]

1 and 2 are longitudinal sectional views showing the first and second embodiments of the present invention, and FIG. 3 is a longitudinal sectional view showing a conventional example. Explanation of symbols 1 …… Oil seal, 2 …… Housing 3 …… Mounting hole, 4 …… Rotary shaft 5 …… Fixed case, 9 …… Slinger 12 …… Seal member, 13 …… Lip part 19 …… Pressure adjustment Chamber, 20 …… Rear side of sealing member B …… Seal fluid, D …… Atmosphere

Claims (1)

[Scope of utility model registration request] 1. An oil seal in which a rotary shaft and a housing are sealed by a slinger fixed to the outer peripheral surface of the rotary shaft and an annular seal member having a lip portion slidably contacting the slinger. The seal member is housed in a fixed case provided in the mounting hole of the housing so as to be movable in the axial direction, the lip portion is formed in a wedge shape in cross section, and is introduced between the back surface of the seal member and the fixed case. An oil seal which is provided with a pressure adjusting chamber that expands by the pressure of the fluid to be pushed and presses the seal member toward the slinger.