JPH0639170Y2 - Lip seal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an improvement of a lip-type seal for sealing the circumference of a rotating shaft.

[Prior Art] Conventionally, as a shaft sealing device used in, for example, a compressor of a car cooler, there is a lip type seal as shown in FIG.

This lip-type seal includes a rubber-made lip member 1 on the sealed space A side in the compressor, a synthetic resin (PTFE or the like) lip member 2 on the anti-sealed space (atmosphere) B side, and the synthetic resin lip member 2. It is composed of a metal backup ring 3 supported from the side opposite to the hermetically sealed space B, and a metal case 4 integrally caulking and fixing the outer peripheral portions of the lip members 1 and 2 and the backup ring 3.

The metal case 4 is airtightly attached to the inner peripheral surface of the shaft hole 8 of the compressor housing 7 through the O-ring 5, and the step portion 8a on the inner peripheral surface of the shaft hole 8 and the inner peripheral surface Both lip members 1 and 2 fixed to the metal snap ring 6 fitted in the annular groove 8b and extending toward the sealed space A.
The inner peripheral surface of the front end of the sliding contact with the outer peripheral surface of the shaft 9 inserted into the shaft hole 8 and the sliding edge 1b projecting from the inner peripheral surface of the front end 1a of the rubber lip member 1 has The refrigerant and the refrigerating machine oil are prevented from leaking to the anti-sealed space B side.

[Problems to be solved by the device]

However, in the above lip-type seal, the rubber-made lip member 1 and the backup ring 3 via the synthetic resin lip member 2 are used.
The pressure in the sealed space A is 5kg / cm
^{When the} pressure is higher than ² , both lip members 1 and 2 bend to the opposite sealed space B side, and the tip of the synthetic resin lip member 2 slightly retracts to the sealed space B side. As shown by the broken line in the figure, the tip portion 1a of the slab solidly contacts the outer peripheral surface of the shaft 9 due to the pressure, and as a result, the sliding heat generation amount increases and the sliding edge 1b hardens and cracks develop. However, there is a problem that the sealing property is deteriorated due to the occurrence of the above.

Therefore, it is conceivable to apply a metal reinforcing ring to the surface of the rubber-made lip member 1 on the sealed space A side so as to reinforce the lip members so as not to bend toward the anti-sealed space B side due to the pressure. However, in this case, there is a problem that the deterioration of the hermeticity due to the impaired followability of the tip portion 1a of the lip member 1 against the radial displacement (shaft wobbling) of the shaft 9 cannot be avoided.

In view of the above, the lip-type seal of the present invention has been made in view of obtaining stable sealing performance for a long period of time.

[Means for Solving the Problems]

In order to solve the above problems, the lip type seal of the present invention is
A metal reinforcing ring is attached to the surface of the lip member on the side of the sealed space except for the tip portion, and the tip portion is formed with a pressure receiving surface for receiving the pressure of the sealed space in the radial direction in opposite directions. In the inner peripheral surface of the portion, an annular concave portion, which is cut in a substantially axial direction, is formed on the side opposite to the sealed space of the sliding edge.

[Action]

According to the present invention, since the lip member is reinforced by the metal reinforcing ring, and the tip portion of the lip member is balanced in the radial direction, the tip of the lip portion does not stick to the shaft due to the pressure of the sealed space. The portion has a large degree of freedom in the radial direction due to the recess extending in the substantially axial direction formed from the side of the sealed space that does not receive pressure, and therefore has good followability to shaft runout.

〔Example〕

The present invention will be described below with reference to an embodiment shown in FIG.

That is, in the lip type seal of this embodiment, a metal reinforcing ring 10 having a cross-sectional shape bent corresponding to the lip member 1 is attached to the surface of the rubber lip member 1 on the sealed space A side. It is reinforced. The tip portion 1a of the lip member 1 is projected and exposed from the tip edge 10a of the reinforcing ring 10, and the surface of the tip portion 1a that faces the sealed space A side has the pressure of the sealed space A from the outer diameter side. A tapered pressure-receiving surface 11 that receives and has a smaller diameter toward the tip and an inverse taper-shaped pressure receiving surface 12 that receives the pressure from the inner diameter side and that has a larger diameter toward the tip are formed corresponding to the radial direction. There is. Also, the tip 1a
On the inner peripheral surface of the sliding edge 1b with the shaft 9 on the side opposite to the sealed space B, there is formed an annular recessed portion 13 which is scooped out in a lateral J-shape in a substantially axial direction. Other configurations are similar to those of the conventional example shown in FIG.

In the above structure, since the rubber-made lip member 1 facing the sealed space A is reinforced almost entirely on the sealed space A side by the metal reinforcing ring 10, the pressure in the sealed space A exceeds 5 kg / cm ^2. Even if it becomes, both lip members 1 and 2 do not bend to the anti-seal space B side, and the tip portion of the rubber-made lip member 1
Since the pressure of the sealed space A acting on 1a is balanced in the radial direction by the pressure receiving surfaces 11 and 12, the tip portion 1a does not stick to the outer peripheral surface of the shaft 9 due to this pressure. Further, since the tip end portion 1a has a large degree of freedom in the radial direction due to the formation of the recessed portion 13, the followability with respect to the axial runout of the shaft 9 is excellent, and as described above, the tip end portion 1a has a pressure. In addition to being balanced, the recess 13 does not receive the pressure in the sealed space A, so that the sliding load on the sliding edge 1b due to the pressure does not increase.

[Effect of device]

As described above, according to the present invention, since the lip member is reinforced by the metal reinforcing ring and the tip end thereof is pressure-balanced in the radial direction, the sliding edge can be solidly contacted with the shaft by the pressure of the sealed space. In addition, since the radial degree of freedom of the tip portion is secured by forming the recessed portion, even if the shaft swings, it can follow this well and exhibit stable sealing performance. Since the sliding load does not increase, the life can be improved.

[Brief description of drawings]

FIG. 1 is a half cutaway view of a state of use showing an embodiment of the present invention,
FIG. 2 is a half-cut cross-sectional view showing a conventional structure in use. 1 rubber lip member, 1a tip part 1b sliding edge, 10 metal reinforcing ring 11,12 pressure receiving surface, 13 recess, A sealed space B anti-sealed space

Claims (1)

[Scope of utility model registration request] 1. A lip formed by holding a rubber-made lip member on the inner periphery of a metal case, the rubber lip member being bent and extending toward the sealed space and having a sliding edge with the outer peripheral surface of the shaft projectingly formed on the inner peripheral surface of the tip portion. A mold seal, wherein a metal reinforcing ring is attached to the surface of the lip member on the side of the sealed space except the tip portion, and the tip portion receives the pressure of the sealed space in the radial direction in opposite directions. And a ring-shaped recess formed in the inner peripheral surface of the tip portion on the side of the sliding edge opposite to the sealed space, the lip-shaped seal being formed in the axial direction.