JP2000065216A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device excellent in reliability for keeping the quantity of pumping due to a screw pumping action of a screw part even at the time of abrasion. SOLUTION: A screw part 5 is provided for the sliding surface of a seal lip 2, which is equipped with plural screw ridges 5a, 5b and 5c different in height so as to be disposed out of a parted position from the tip end of the lip of the seal lip 2 toward the lip root direction as the height of each ridge becomes higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device used for a rotary shaft sealing portion of various devices.

[0002]

2. Description of the Related Art Conventionally, as this kind of sealing device, there is one shown in FIG. 2A, for example. That is, the sealing device 100
Are mounted between a housing 101 and a rotating shaft 102 which are concentrically and relatively rotatably assembled with each other.

The sealing device 100 includes an annular seal body 104 fitted and fixed in a shaft hole 103 of a housing 101,
A seal lip 106 and a lip portion 105 having a dust lip 107 are integrally provided on the inner peripheral side of the seal main body 104.

[0004] As shown in an enlarged view in FIG. 2 (b), a screw portion 108 that performs a screw pump action by the relative rotation with respect to the rotary shaft 102 is provided on the sliding surface of the seal lip 106 with the rotary shaft 102. Was provided to improve the sealing performance.

[0005]

However, in the case of the above-mentioned prior art, when the wear of the seal lip 106 progresses, the screw portion 108 also wears, and the pump amount by the screw pump action becomes larger than in the initial state. descend.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide an excellent reliability in maintaining a pump amount by a screw pump action of a screw portion even when worn. It is to provide a sealing device.

[0007]

In order to achieve the above object, the present invention seals an annular gap between two members which rotate concentrically relative to each other, and is slidable with respect to one member. In the sealing device provided with a seal lip that comes into sealing contact with the seal lip, the sliding surface of the seal lip is disposed at a position away from the lip tip of the seal lip in the lip root direction as the height of the screw thread increases. A screw portion having a plurality of screw threads having different heights is provided.

Therefore, a plurality of threads having different thread heights perform the screw pumping operation in order from the thread having a smaller height in accordance with the wear of the seal lip. The pump amount by the screw pump action can be maintained.

[0009] It is preferable that the plurality of threads having different heights have different heights in three stages of low, medium and high.

[0010] Accordingly, the thread of the thread portion performs the screw pumping operation in the order of low, medium and high in accordance with the wear of the seal lip. The pump amount by the screw pump action can be maintained.

[0011]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The sealing device according to the present embodiment is mounted between a housing that is rotatably mounted concentrically with respect to one another and a rotating shaft as one member.

As in the prior art, the sealing device includes an annular seal body fitted and fixed in a shaft hole of the housing, a lip integrally provided on the inner peripheral side of the seal body,
It is composed of

Next, the seal lip of the lip portion, which is a feature of the present invention, will be described in detail with reference to FIG.

FIG. 1A is an enlarged view showing an enlarged lip of the sealing device according to the embodiment of the present invention.
FIG. 1B is an enlarged view showing a thread portion on a sliding surface of the seal lip, and FIG. 1C is a cross-sectional view taken along a line AA in FIG. 1B.

In FIG. 1 (a), a lip portion 1 includes a seal lip 2 for preventing fluid leakage while sliding on a rotating shaft;
And a dust lip 3 for preventing intrusion of external dust.

A spring 4 is provided on the outer periphery of the seal lip 2 to increase the force for pressing the seal lip 2 against the rotating shaft.

In the present embodiment, the dust lip 3
Is a non-sealing target fluid side A, and an upper side where the sealing lip 2 is provided is a sealing target fluid side O for sealing a sealing target fluid such as oil, water, or a chemical.

On the sliding surface of the seal lip 2 with the rotary shaft, there is provided a screw portion 5 which performs a screw pump operation by relative rotation with the rotary shaft.

As shown in FIG. 1C which shows a cross section taken along the line AA of FIG.
a), a plurality of sets of thread 5a, 5b, and 5c that are different in three stages of (a), middle (5b), and high (5c) are arranged side by side on the screw portion 5. That is, as shown in FIG. 1 (b), the screw threads 5a, 5b, 5c having three different heights of low, middle, and high are arranged in the order of low, middle, high, low, middle, high,. A plurality of them are regularly arranged.

As described above, the order in which the threads 5a, 5b, and 5c are arranged is, as described above, the order of low, high, middle, high, and high.
Threads 5a, 5 different in three stages, such as middle, low
It suffices that a plurality of b and 5c are arranged as one set and a plurality of sets are arranged.

The thread 5a, 5b, 5c having three different heights of low, medium, and high is provided with a predetermined distance from the lip tip of the seal lip 2 toward the lip root as the height of the thread increases. They are arranged from positions separated by L.

That is, the low-height thread 5a is arranged from the lip tip, and the middle-height thread 5b is arranged from the lip tip where the low-height thread 5a is arranged to the lip root direction. The thread 5c having a high height is arranged from a position spaced a predetermined distance L in the lip root direction from the position where the thread 5b having an intermediate height is arranged.

However, the distance itself may be gradually reduced or extended without arranging the thread whose height becomes higher at every equal predetermined distance L.

In the seal lip having the thread portion 5 described above, when the thread 5a having a low height is worn together with the wear of the seal lip 2, the thread 5b having a medium height acts as a pump to reduce the pump amount. When the thread 5b having a medium height wears due to further progress of the wear of the seal lip 2, the thread 5c having a high height performs a pumping operation to supplement the pump amount. , Even when worn
Can be maintained in the same manner as in the initial state.

In addition, as long as the sealing device is provided with the sealing lip 2 having the screw portion 5 according to the present embodiment, various shapes can be applied to the sealing device.

In addition to the threads having different heights in three stages, a plurality of threads having various heights such as a thread having different heights in multiple stages and a thread having different heights in two stages are provided. Can be used.

[0028]

As described above, according to the present invention, as the height of the thread on the sliding surface of the seal lip increases, the height of the plurality of seal lips differing from the tip of the lip in the lip root direction is different. With the provision of the thread portion having the thread portion, a plurality of thread portions having different heights of the thread portion perform the screw pumping operation in order from the thread having a lower height in accordance with the wear of the seal lip, Even during wear, the amount of pumping by the screw pumping action of the screw portion can be maintained.

The plurality of threads having different heights have a low height,
Since the threads are different in three stages of medium and high, according to the wear of the seal lip, the thread of the thread part performs the screw pump action in the order of low, medium and high thread. Become
Even during wear, the amount of pumping by the screw pumping action of the screw portion can be maintained.

[Brief description of the drawings]

FIG. 1A is a diagram showing a lip portion of a sealing device according to an embodiment, and FIG. 1B is a diagram showing a thread portion on a sliding surface of a sealing lip; FIG. 1C is a diagram showing a cross section taken along line AA of FIG.

FIG. 2 (a) is a view showing a conventional sealing device,
FIG. 2B is a view showing a lip portion of the conventional sealing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1,105 Lip part 2,106 Seal lip 3,107 Dust lip 4 Spring 5,108 Thread part 5a Thread (low) 5b Thread (medium) 5c Thread (high) 100 Sealing device 101 Housing 102 Rotation axis 103 Axis Hole 104 Seal body

Claims (2)

[Claims] 1. A sealing device for sealing an annular gap between two members concentrically rotating relative to each other and having a seal lip slidably and sealingly contacting one member, wherein the sliding of the seal lip is performed. The moving surface is provided with a thread portion having a plurality of threads having different heights arranged from a position away from the lip tip of the seal lip in the lip root direction as the height of the threads increases. And sealing device. 2. The sealing device according to claim 1, wherein the plurality of threads having different heights have three different levels of height, low, medium, and high.