JPH01112081A - Lip seal device - Google Patents

Abstract

PURPOSE:To provide an effective lip seal device, by a method wherein an annular groove formed in succession in the peripheral direction of a rotary shaft is formed in the seal surface with the rotary shaft of a slip, and a first seal surface located nearer to the sealed fluid side than the annular groove is further smoothly formed than a second seal surface on the opposite side. CONSTITUTION:A first seal surface 10a located nearer to the sealed fluid side than an annular groove 9 is further smoothly formed than a second seal surface 10b on the opposite side. Thus, in a state in which a lip 6 is incorporated in a rotary shaft 2 and before rotation of the rotary shaft 2, the first seal surface 10a being further smooth compared with the coarse second seal surface 10b is excellently adhered to the outer peripheral surface of the rotary shaft 2 to effect an effective seal action. With the rotary shaft rotated, the coarse second seal surface 10b is further rapidly adapted itself to the surface of the rotary shaft 2 by dint of initial friction between the rotary shaft 2 and the second seal surface than the first seal surface 10a. Thereby, after the second seal surface 10b is adapted itself to the surface of the rotary shaft 2, during the stop of the rotary shaft 2, the second seal surface 10b is further firmly adhered to the rotary shaft 2 than the first seal surface 10a.

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 rotary shaft that is rotatably supported, an outer peripheral part is attached to the case, and an inner peripheral part is curved toward the sealing fluid side. It is well known to have a lip that is in sliding contact with the outer peripheral surface of the rotating shaft.゛Also, a similar lip seal device is known in the past, in which a spiral groove is formed on the sealing surface of the lip with the rotating shaft (Japanese Patent Laid-Open No. 126635/1983).
.

"Problems to be Solved by the Invention" However, in the lip seal device in which such a spiral groove is formed on the sealing surface of the lip with the rotating shaft,
As shown in the experimental results later, the sealing performance during rotation is better than that of a normal lip seal device that does not form a spiral groove, but the sealing performance when the rotating shaft stops rotating is better than that of the normal lip seal device mentioned above. The results were far worse than the equipment itself.

"Means for Solving the Problems" In view of the above circumstances, the present invention provides the lip seal device with an annular groove continuous in the circumferential direction of the rotating shaft on the sealing surface of the lip with the rotating shaft. The first sealing surface on the sealing fluid side of the annular groove is formed to be smoother than the second sealing surface on the opposite side.

"Operation" If an annular groove is formed on the sealing surface of the lip, the wall thickness of the annular groove part will be thinner than other parts, so that part will be more likely to be pressed and deformed by the pressure from the sealed fluid side, thus sealing the lip. Parts of the surface on both sides of the annular groove are particularly strongly pressed against the outer circumferential surface of the rotating shaft. Since the annular grooves are continuous in the circumferential direction, the contact area is also continuous in the circumferential direction, and moreover, there are two
22 because you get a ring-shaped contact part of the book! A sealing effect can be obtained. As a result, in the present invention,
Due to the above-mentioned double sealing action, it is possible to obtain an excellent sealing effect both during rotation and when stopped, compared to the conventional device.

Furthermore, in the present invention, the first sealing surface on the sealed fluid side of the annular groove is formed to be smoother than the second sealing surface on the opposite side, so that the lip is incorporated into the rotating shaft. Before the rotating shaft is rotated, the smooth first sealing surface is in better contact with the outer peripheral surface of the rotating shaft than the rough second sealing surface, making it possible to obtain an effective sealing action. can. Then, when the rotating shaft is rotated, the first
The second seal surface, which is rougher than the seal surface, quickly adapts to the surface of the rotating shaft due to initial wear with the rotating shaft. At the time of stopping, the second sealing surface comes into closer contact with the outer circumferential surface of the rotating shaft more reliably than the first sealing surface.

Therefore, in the present invention, the effect is always maintained from the state before the lip is incorporated into the rotating shaft and the rotating shaft is rotated, to the state after the lip is initially worn when the rotating shaft is rotated. A perfect sealing effect can be obtained.

``Embodiment'' The present invention will be described below with reference to the illustrated embodiment. In FIG. A lip seal device 3 according to the present invention seals between the inner circumferential surface of the hole 1a and the outer circumferential surface of the rotating shaft 2. This lip seal device 3 is composed of four members, namely, a case 4 made of metal, a sealing member 5 made of rubber or synthetic resin, a lip 6 made of rubber or synthetic resin, and a spacer 7 made of metal. ing.

The case 4 is formed into a ring shape so as to surround the rotating shaft 2, and its axial cross-sectional shape includes an inner circumferential axial portion 4a located on the inner circumferential side and extending in the axial direction; A first radial portion 4b extending radially outward from the right end of the inner axial portion 4a; and a first radial portion 4b extending radially outward from the right end of the inner axial portion 4a; It consists of an outer circumference side axial direction part 4c extending in parallel to the outer circumference side, and a second radial direction part 4d further extending radially inward from the left end of the outer circumference side axial direction part 4c. It is formed into a roughly rectangular ring shape with the left end portion cut out.

In the case 4 before the lip 6 and spacer 7 are assembled, the second radial portion 4d extends in the same axial direction as the outer axial portion 4C, and the lip 6 and spacer 7 are not assembled. Then, by bending that portion radially inward, the left end portion on the inner circumferential side described above is formed into a rectangular ring shape with a notch.

Further, the seal member 5 is integrally attached to the case 4 by vulcanization or adhesive, and the seal member 5 is integrally attached to the case 4 by vulcanization or adhesive.
Excluding the outer circumferential side portion of d, the outer circumferential side axial direction continuously covers the outer circumferential side of the first radial portion 4b and the inner circumferential side portion of the inner circumferential side axial portion 4a from the outer circumferential side of the interior 4C, and The inner circumferential part 8 of the case surrounded by the circumferential axial part 4a, the first radial part 4b, and the outer circumferential axial part 4C is filled. Furthermore, the remaining portion of the inner circumferential side portion of the outer circumferential side axial direction portion 4c and the second radial direction portion 4 continuous thereto.
It continuously covers the inner peripheral part of d.

The left end surface of the sealing member 5 filled in the case inner circumference 8 is a support surface 5a, and this support surface 5a and the spacer 7 keep the radial outer circumference of the lip 6 oriented in the radial direction. sandwiched from both sides, and the spacer 7
is supported by a second radial portion 4d that is bent radially inward at its left end surface.

Incidentally, a part of the support surface 5a that supports the lip 6 has a circumferentially continuous protrusion 5b that protrudes toward the lip 6 at a position radially outward from the inner axial portion 4a of the case 4. At the same time, an annular groove 5c is formed at a radially outward position continuous with the protrusion 5b.

Therefore, the lip 6 is formed between the support surface 5a and the spacer 7.
When the radially outer peripheral portion of the supporting surface 5a is held, the protruding portion 5b is relatively larger than the other portions of the supporting surface 5a, and a portion thereof bulges into the annular groove 5c and smoothly elastically deforms. Even when the sealing member 5 ages and its elasticity decreases, the contact state between the protruding portion 5b and the lip 6 is maintained well, so that the sealing fluid flows to the left end of the spacer 7 and the lip 6. Gap and lip 6
Leakage through the gap between the right end surface of the seal member 5 and the support surface 5a of the seal member 5 can be effectively prevented for a long period of time.

At the same time, the lip 6 is connected to the spacer 7 and the case 4 at a position radially inward from the protrusion 5b.
Since the left end surface of the inner circumferential side axial portion 4a of the lip 6 is sandwiched between the lip 6 and the left end surface of the inner circumferential axial portion 4a, the sandwiching state can be maintained constant even when the seal member 5 ages. It is possible to prevent the occurrence of a situation in which the clamping force of the lip 6 decreases and the lip 6 rotates with the rotation of the rotating shaft 2.

Furthermore, when the lip 6 is held between the spacer 7 and the left end surface of the inner axial portion 4a of the case 4, the position where the lip 6 is firmly held is set to the position closest to the rotating shaft 2. position, more specifically, the innermost position of the spacer 7, so that the curved portion of the lip 6 is not deformed, for example, when the lip 6 is held between the spacer 7 at a position outward from the middle part. It is also possible to prevent problems such as the sealing surface becoming easier and displacing in the axial direction with respect to the rotating shaft 2, resulting in surface roughening of the sealing surface or deterioration of the durability of the lip 6.

In this embodiment, the seal member 5 is provided on the left end surface of the inner circumferential axial portion 4a, but since the wall thickness of the seal member 5 at that portion is as thin as 0.1 to 0.5 mm, the seal member 5 is 5 aging, the clamping force does not substantially decrease, and furthermore, the thin sealing member 5 prevents the left end surface of the metal inner peripheral axial portion 4a from damaging the lip 6. can.

Further, the sealing member 5 is provided with a plurality of annular protrusions 5d continuous in the circumferential direction at predetermined intervals in a portion covering the outer circumferential side of the outer circumferential axial portion 4c, and the annular protrusions 5d
By press-fitting it into the inner circumferential surface of the stepped hole 1a of the housing 1, it is possible to keep that part liquid-tight.

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 brought into elastic contact with the outer circumferential surface of the rotating shaft 2 due to its own elasticity. , the sealing fluid present on the left side of the lip 6 is prevented from leaking to the atmosphere side on the right side.

A circumferentially continuous annular groove 9 is formed on the sealing surface of the lip 6 with respect to the rotating shaft 2, and the sealing fluid side of the sealing surface is the first sealing surface 10a1. 2 sealing surfaces 10b, and the surface of the first sealing surface 10a is formed to be smoother than the surface of the second sealing surface lOb.

The cross section of the annular groove 9 is formed into a semicircular shape slightly crushed toward the sealing fluid side, as shown in an enlarged view in FIG. The contact portion 9a between the annular groove 9 and the second sealing surface tab is formed at a substantially right angle and its corners are formed as sharply as possible, while the contact portion 9b between the annular groove 9 and the second sealing surface tab is continuous with a gently curved surface.

According to the above-mentioned structure, since the annular groove 9 is formed in the sealing surface of the lip 6, the wall thickness of the lip 6 becomes thinner in that part, and the part deforms when it receives pressure from the sealing fluid side. become more susceptible to As a result, both contact portions 9a and 9b of the annular groove 9 are relatively strongly pressed against the outer circumferential surface of the rotating shaft 2, and each contact portion 9a and 9b is shaped like a continuous line or band in the circumferential direction. come into contact with. Therefore, two existing contact parts are obtained for one annular groove 9, so that a double sealing effect is obtained by each contact part.

When the rotating shaft 2 is rotated in this state, the first sealing surface 10a tends to be slightly raised from the outer peripheral surface of the rotating shaft 2. There is a tendency for contact to be easily interrupted.

In particular, when the contact portion 9a is formed into a smooth curved surface, the contact portion of the contact portion 9a with the rotating shaft 2 tends to fluctuate in the axial direction due to the tendency of the first seal surface 10a to become loose. As a result, a positional shift occurs in the axial direction between some contact portions and other contact portions, and continuous contact in the circumferential direction is likely to be interrupted.

However, if the contact portion 9a is formed as sharply as possible, the sharp corners will come into contact with the outer circumferential surface of the rotating shaft 2, making it difficult for the contact portion to be misaligned. Good continuous contact is maintained and leakage of the sealing fluid is suppressed.

On the other hand, the other contact portion 9b is located outside the contact portion 9a, and can maintain continuous contact in the circumferential direction better than the contact portion 9a on the sealing fluid side. Although it is preferable to form the contact portion 9b with a sharp edge from the viewpoint of preventing leakage of the sealing fluid,
Since lubrication by the sealing fluid cannot be expected, the second seal surface 1
Since there is a risk of causing a problem in the durability of the contact portion 9b, the contact portion 9b is formed into a gently curved surface so that the sealing fluid can be introduced into the second sealing surface 10b for lubrication.

Furthermore, in this embodiment, since the first sealing surface 10a is formed to be smoother than the second sealing surface tab, before the lip seal device 3 is assembled to the housing 1 and the rotating shaft 2 is rotated for the first time. until the smooth first sealing surface 10
The smooth first sealing surface 1 is more securely attached to the outer circumferential surface of the rotating shaft 2 than the second sealing surface 10b, which is rougher.
0a provides a good sealing effect.

On the other hand, when the rotation of the rotating shaft 2 starts, the second sealing surface 10b, which is rougher than the first sealing surface 10a,
Due to the initial wear, it quickly adapts to the surface of the rotating shaft 2. After the second sealing surface 10b has become familiar with the surface of the rotating shaft 2, when the rotating shaft 2 stops rotating, the second sealing surface 10b is more securely attached to the outer peripheral surface of the rotating shaft 2 than the first sealing surface 10a. It comes to be in close contact with. In other words, even when the rotating shaft 2 is rotated, the smooth first sealing surface 10a is less susceptible to initial wear and has a strong tendency to maintain its initial state, so it does not easily adapt to the surface of the rotating shaft 2. Eventually, the second sealing surface 10b will perform a better sealing action than the first sealing surface 10a.

In short, even if the surface of the second seal surface 10b is made rough to make it fit easily to the rotating shaft 2, the second seal surface Job
While the surface of the first sealing surface 10a is rough, the smooth first sealing surface 10a performs a good sealing action.

Next, FIG. 3 shows another embodiment of the present invention, in which the lip seal device 13 of this embodiment has two first lips 1
6A and a second lip 16B.

The inner peripheral portions of each of the lips 16A, 16B are curved toward the sealing fluid side and slidably contact the outer peripheral surface of the rotating shaft 12, and the first lip 16A, which is on the sealing fluid side, is substantially different from the above embodiment. An annular groove 19 having the same configuration is formed, and a first sealing surface 20a is formed on the left side of the annular groove 19, and a #g2 sealing surface 20b is formed on the right side.

The cylindrical case 14 that supports the outer peripheral portions of the first lip 16A and the second lip 16B includes a large diameter portion 14a, a small diameter portion 14b, and a stepped portion 14c between the two, and the left end of the small diameter portion 14b. Case 1 is folded outward in the radial direction.
An annular groove 25 is formed on the outer peripheral surface of 4. A seal member 26 is fitted into this annular groove 25, and the seal member 26 seals between the housing 11 and the case 14.

Further, the right end portion of the large diameter portion 14a is bent radially inward to form a caulked portion 14d, and between this caulked portion 14d and the step portion 14c, the plate 27, the A first lip 16A, a sealing member 29 in which a rigid plate 28 such as a metal washer is embedded, and the second lip 1
6B and plate 30 are integrally sandwiched and connected.

The plate 27 is manufactured from metal and has an outer diameter smaller than the inner diameter of the large diameter portion 14a by a predetermined amount, and is formed on the outer periphery of the first lip 16A to protrude toward the sealed fluid side. By engaging the protrusion 16Aa with the outer peripheral surface of the plate 27, the first lip 16A is prevented from being pulled out. In addition, the first lip 16
An annular groove 1 is provided on the outer periphery of A on the opposite side of the protrusion 16Aa.
6Ab is formed, and the space formed by this annular groove 16Ab is used as a relief part for elastic deformation when the rubber seal member 29 is assembled into the case 14.

Further, the inner circumferential surface of the sealing member 29 has a second lip 16B.
The curved surface 29a is formed along the sealed fluid side curved surface of the second lip 16B, and this curved surface 29a prevents the inner circumferential portion of the second lip 16B from being displaced to the left in the axial direction more than necessary. The tip of the lip 16B is the first lip 16
It is made to prevent A from polymerizing more than necessary.

Further, the plate 30 located at the right end is made of metal and has a simple washer shape, but the gap t° between its inner circumferential surface and the outer circumferential surface of the rotating shaft 12 has become smaller due to some reason. The gap is set to be small enough to prevent the inner peripheral portion of the lip 18B from turning over to the right side.

It is clear that even in this embodiment having the above configuration, the same effects as in the previous embodiment can be obtained by the annular groove 19 provided in the first lip 16A.

Next, the effects of the present invention will be explained based on the test results shown in FIG.

This test result shows the result of measuring the amount of leakage by incorporating the lip seal device 3 shown in FIG. 1 into a swash plate type compressor. In this test, the suction side pressure of the swash plate compressor was set at 1.5 to 2.5 Kg/cm'
, the discharge side pressure is set to 13 to 18 Kg/c rn", and 4
After continuously rotating at 500 rpm for 24 hours, the motor was stopped for 24 hours, and this was repeated four times, and the total leakage amount during rotation and the total leakage amount during stoppage were measured.

In addition, as a conventional product A for comparison, the annular groove is omitted from the sealing surface of the lip 6, and as a conventional product B, the annular groove is omitted from the sealing surface of the lip 6, and a spiral groove is formed on the sealing surface. We used a device with . Of course, the spiral direction of this spiral groove is formed in the direction in which the sealing fluid leaked to the sealing surface due to the rotation of the rotating shaft 2 is returned.

As shown in the test results in Figure 4, compared to conventional products A and B, the product of the present invention has a smaller amount of leakage both when the rotating shaft 2 is rotating and when it is stopped, and has a good seal. performance is obtained.

In each of the above embodiments, when the thickness t of each lip 6.16A is 1 mm, the distance from the tip of each lip to the annular groove 9.19! When the sealing performance was measured by changing the distance 12 in the range of 0.3 to 1.1 m, it was found that the sealing performance tended to be generally better as the distance 1 was increased. The width of the annular groove 9.19 is also 0.
2-1.2. When the width was varied within the range of mm, it was found that the larger the width, the better the sealing properties tended to be.

"Effects of the Invention" As described above, according to the present invention, the amount of leakage can be reduced both during rotation and when stopped, and moreover, before the lip is incorporated into the rotating shaft and the rotating shaft is rotated. As a result, an effect can be obtained in that an effective sealing action can always be obtained even after the rotation shaft has been rotated and the lip has passed through the initial four stages.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional view showing another embodiment of the present invention, and FIG. 4 is a diagram showing the test results of measuring the leakage amount of the glue tube reel device shown in FIG. 1 and the conventional product. be. 1.11... Housing 2.12... Rotating shaft 3.13... Lip seal device 4.14... Case 5.29-... Seal member 6.16A...
Lip 9.19--Annular groove 9a, 9b-
...Connection parts 10a, 20a--first sealing surfaces 10b, 20b--second sealing surfaces

Claims (1)

[Scope of Claims] A case surrounding a rotating shaft rotatably supported;
A lip seal device comprising a lip whose outer peripheral part is attached to the case and whose inner peripheral part is curved toward the sealed fluid side and is in sliding contact with the outer peripheral surface of the rotating shaft, wherein the lip seals with the rotating shaft. The sealing surface is provided with an annular groove continuous in the circumferential direction of the rotating shaft, and the first sealing surface on the sealed fluid side of the annular groove is formed to be smoother than the second sealing surface on the opposite side. Lip seal device.