JPH0337483A - Lip seal device - Google Patents

Abstract

PURPOSE:To secure an excellent sealing effect by mounting the outer circumferential section of an elastic presser member, thereby over-lapping its inner circumferential surface onto the outer circumferential surface of a lip at its inner circumferential side in such a way as to be energized to the rotating shaft side of the lip. CONSTITUTION:A lip seal device 3 is made up out of a metallic case 4, a presser member 5 made of a soft material such as rubber and the like, a lip 6 which is relatively hard and durable, and of a metallic spacer 7. The case 4 is formed in such a way that it encloses a rotating shaft 2, and is also formed into a U-shape configuration in cross section by means of a cylindrical section 4a extending in the axial direction and flange sections 4b and 4c extending in the radial direction. The member 5 covers the outside and inside sections of the section 4b, and furthermore, the inner circumferential side section of the section 4a in succession. The inner end section in the radial direction of the section 4b is formed with a presser section 5a, and the presser section 5a is energized to the direction that the inner circumference at the tip end section of the lip 6 is closely brought in contact with the rotating shaft 2. The outer circumferential section in the radial direction of the lip 6 is integrally connected with the case 4 by a spacer 7 in fluid sealing relation.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a lip seal device having a lip that slides into contact with a rotating shaft.

``Prior Art'' Conventionally, a lip seal device has a case that surrounds a rotation shaft that is rotatably supported, an outer peripheral end part is attached to the case, and an inner peripheral tip part is curved toward the sealing fluid side. A lip that is in sliding contact with the outer circumferential surface of the rotating shaft, and a sealing surface of the lip with the rotating shaft (this includes an annular groove continuously formed in the circumferential direction of the rotating shaft) is known. There is (
JP-A-1-112082).

In addition, as a lip seal device with another configuration, the outer peripheral ends of two lips are attached to the case, and the inner peripheral ends of each lip are curved toward the sealing fluid side and slid onto the outer peripheral surface of the rotating shaft. There is known a device in which the tip of one lip that is in contact with the sealing fluid side presses the tip of the other lip to bias it toward the rotating shaft (Japanese Utility Model Publication No. 6120569). .

``Problem to be solved by the invention'' In the former lip seal device, since an annular groove is formed in the above-mentioned rib, the wall thickness of the annular groove portion is thinner than other portions, which reduces the pressure on the sealed fluid side. As a result, that part becomes more likely to be pressed and deformed. As a result, parts of the sealing surface on both sides of the annular groove are particularly strongly pressed against the outer circumferential surface of the rotating shaft, and since this annular groove is continuous in the circumferential direction, the contact area is also circumferential. It becomes continuous in the direction. Therefore, two annular contact parts are obtained for one annular groove, so a double sealing effect is obtained, and thereby an excellent sealing effect can be obtained both when rotating and when stopped. becomes possible.

However, since the above-mentioned lip is usually manufactured from relatively hard PTFE etc. in consideration of durability, if large vibrations are applied to the lip seal device, or there is a large misalignment or shaft wobbling of the rotating shaft, the lip may be damaged. The tip of the tube could not follow its vibrations (it would float up, and there was a risk of leakage).

On the other hand, in the latter lip seal device, the two lips have a double sealing effect (combiningly, a good sealing effect can be obtained), and in particular, the lip on the sealed fluid side is relatively If manufactured, the tip of this lip or the other lip is pressed against the rotating shaft, so even if the other lip is made of a relatively hard material with high durability, it can be prevented from lifting off from the rotating shaft. In the past, large vibrations were applied to the lip seal device,
A good sealing effect can be obtained even if there is a large misalignment or shaft wobbling of the rotating shaft.

However, on the other hand, if the lip on the sealed fluid side is made of relatively soft rubber or the like, the durability of the lip will be reduced, and the seal portion will be easily damaged, especially under high speed and high pressure. If the sealing effect of the sill part is lost, it becomes essentially a single lip, making it difficult to obtain a good sealing effect.

"Means for Solving the Problems" In view of such circumstances, the present invention provides the above-mentioned former lip seal device, that is, a case that surrounds a rotating shaft that is rotatably supported, and an outer peripheral portion of which is attached to the case. a lip that is attached and whose inner circumference is curved toward the sealed fluid side and is in sliding contact with the outer circumferential surface of the rotating shaft; In the lip seal device having an annular groove formed therein, the outer circumferential portion of an elastic presser member is attached to the case, and the inner circumferential portion of the presser member is overlapped with the outer circumferential surface of the inner circumferential portion of the lip. The lip is biased toward the rotating shaft, and the inner peripheral end of the holding member is separated from the rotating shaft.

"Function" According to the above structure, an excellent sealing effect can be obtained by the double sealing action 1 on both sides of the annular groove formed in the lip, and the pressing member that presses the tip of the lip is a seal. Since it is not directly involved in the action, the presser member can be made of a flexible material such as rubber.Therefore, even if large vibrations are applied to the lip sill device, or there is a large misalignment or vibration of the rotating shaft, the holding member can be made of a flexible material such as rubber. Since the tip portion can always be brought into close contact with the rotating shaft by pressing the holding member, an excellent sealing effect can be obtained even under the above-mentioned adverse conditions.

``Embodiment'' The present invention will be described below with reference to the illustrated embodiment. A rotating shaft 2 is rotatably supported by passing through a stepped hole 1a formed in a housing 1, and the inner peripheral surface of the stepped hole 1a is rotatably supported. A lip seal device 3 according to the present invention seals between the rotary shaft 2 and the outer circumferential surface of the rotating shaft 2. This lip seal device 3 is made up of four members: a metal case 4, a holding member 5 made of a relatively soft material such as rubber, and a relatively hard but durable material such as PTFE. Lip 6 and Zara (
It is composed of a spacer 7 made of metal.

The case 4 has a ring shape surrounding the rotating shaft 2, and its axial cross-sectional shape includes a cylindrical portion 4a extending in the axial direction, and a cylindrical portion 4a extending radially inward from both ends of the cylindrical portion 4a. The extending flange portions 4b and 4c form a U-shaped cross section.

The pressing member 5 is integrally attached to the case 4 by vulcanization bonding or adhesion, and extends from the outer peripheral side of the cylindrical portion 4a to the outer and inner portions of the flange portion 4b.
Roughly, the inner peripheral side portion of the cylindrical portion 4a is continuously covered.

A radially inner end portion of the flange portion 4b of the holding member 5 is formed with a holding portion 5a extending diagonally forward from the inner end portion toward the rotating shaft 2. This presser part 5a
In the assembly state, the inner periphery of the tip of the lip 6 is urged in the direction of coming into close contact with the rotating shaft 2.The tip of the holding portion 5a is spaced apart from the rotating shaft 2. , the presser portion 5a is in sliding contact with the rotating shaft 2 and the lip 6 is
This ensures that the lubrication conditions are not affected.

Further, a relief portion 5b is formed on the base side of the presser portion 5a of the presser member 5, that is, on the flange portion 4b side, to make the presser member 5 M@ from the surface of the lip 6.
Since the sealing fluid pressure can be concentrated on the holding part 5a, the tip of the lip 6 can be securely sealed against the rotating shaft 2.
I can do it. Therefore, even if the tip of the lip 6 is shaken due to vibration or misalignment or shaft wobbling of the rotating shaft, it can follow it well and keep the inner periphery of the tip of the lip 6 in close contact with the rotating shaft 2 at all times. It looks like it's straining.

The radially outer circumferential portion of the lip 6 includes an inner portion of the flange portion 4b of the presser member 5 and a cylindrical portion 4a.
The lip 6 is integrally connected to the case 4 in a fluid-tight manner by a spacer 7 disposed between the outer circumference of the lip 6 and the flange portion 4c.

Further, the inner circumferential portion of the lip 6 is curved so as to protrude toward the sealed fluid side, that is, to the left, and the inner circumferential surface side of the protruding portion is applied to the outer circumferential surface of the rotating shaft 2 with its own elasticity and the presser portion 5a. Due to the elasticity of the lip 6, the sealing fluid present on the left side of the lip 6 is prevented from leaking to the atmosphere side on the right side. An annular groove 9 continuous in the circumferential direction is formed on the sealing surface of the lip 6 with the rotating shaft 2.

According to the above configuration, since the annular groove 9 is formed on the sealing surface of the lip 6, the wall thickness of the lip 6 becomes thinner in that area, and this area is easily deformed when receiving the pressure of the sealing fluid. Become. As a result, both side portions of the annular groove 9 come to be relatively strongly pressed against the outer circumferential surface of the rotating shaft 2, and each contact portion comes into contact in a continuous line or band shape in the circumferential direction. Therefore, for one annular groove 9, 2
Since an annular contact part of the book is obtained, a double sealing action can be obtained by each contact part.

Further, since the presser member 5 that presses the tip of the lip 6 does not participate in the sealing action, the sealing effect will not be reduced even if the presser member 5 is made of a flexible material such as rubber as described above. By manufacturing the presser member 5 from a flexible material, even if large vibrations are applied to the lip seal device 3 or the rotary shaft 2 is misaligned or shakes, the tip of the lip 6 can be held with a flexible presser. The member 5 (thus, can always be brought into tight contact with the rotating shaft 2).Therefore, even under the above-mentioned adverse conditions, a stable and excellent sealing effect can always be obtained.

Furthermore, if the tip of the presser member 5 is brought into contact with the rotating shaft 2 and sealed at that portion, the lubrication conditions for the sealing surface of the lip 6 will deteriorate, and the sealing surface will be damaged. However, since the tip of the presser member 5 is separated from the rotating shaft 2, it is possible to prevent such a situation from occurring. Therefore, for this reason, at least a portion of the tip of the presser member 5 may be separated from the rotating shaft 2.

"Effects of the Invention" As described above, according to the present invention, not only can an excellent sealing effect be obtained by the double sealing action on both sides of the annular groove formed in the lip, but also the presser foot that presses the tip of the lip. Since the member does not participate in the sealing action, the holding member can be made of a flexible material such as rubber. Even if large vibrations are applied to the lip seal device, or the rotating shaft is misaligned or shakes, the tip of the lip can always be held firmly against the rotating shaft by the presser member, which is always excellent. The effect of being able to obtain a sealing effect is obtained.

[Brief explanation of drawings]

The figure is a sectional view showing one embodiment of the present invention. 1...Housing 3...Lipstick 5... Pressing member 5b... relief part 9...Annular groove 2...Rotation axis Sail device 4...case 5a...presser part 6...Lip

Claims (1)

[Scope of Claims] A case surrounding a rotatably supported rotary shaft; On the sealing surface between the lip that is in sliding contact with the surface and the rotation axis of the lip,
In a lip seal device equipped with an annular groove continuously formed in the circumferential direction of a rotating shaft, an outer peripheral end of an elastic presser member is attached to the case, and an inner peripheral end of the presser member is attached to the lip. A lip seal device characterized in that the tip of the lip is superimposed on the outer circumferential surface of the tip of the presser member to urge the tip of the lip toward the rotating shaft, and the tip of the holding member is separated from the rotating shaft.