JPH0614143Y2 - Lip seal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a structure of a lip-type seal used for axially sealing a rotating shaft portion of a machine body such as a compressor for a car air conditioner.

[Prior Art] A high-pressure lip-type seal conventionally used as a shaft sealing device such as a compressor for a car air conditioner of this type has been inserted into a housing of a machine body (not shown) as illustrated in FIG. The tip of the tip (1
The atmospheric side (A) of the rubber lip (1) with which a) is slidably contacted is backed up by the synthetic resin lip (2) made of trifluoroethylene resin or tetrafluoroethylene resin, and the atmospheric side (A). There is a structure in which a high-pressure (about 5 kgf / cm ² ) sealed liquid side (B) is sealed.

[Problems to be Solved by the Invention] However, in the lip type seal having such a conventional structure, since the rubber lip (1) is formed of one kind of rubber lip material, the rotation shaft (S) is When the temperature of the rubber lip (1) rises due to the temperature rise of the sealing liquid due to the rotation, the surface pressure of the rubber lip tip (1a) is indicated by the solid line from the sharp tip contact state shown by the dotted line in FIG. There is a problem in that it deforms to a harassment state, whereby the width of the sealing surface with the rotating shaft (S) widens, the rotating shaft is easily worn, and the sealing performance becomes unstable.

[Object of the Invention] The present invention has been made under the above circumstances, and an object of the present invention is to provide a lip-type seal capable of maintaining a stable sealing property. is there.

[Means for Solving the Problems] In order to solve the above-described problems, the present invention provides a rubber lip whose tip end is in sliding contact with the circumference of a rotary shaft, and a plurality of types of rubber having different thermal expansion coefficients. Made of laminated lip material,
In addition, the lip material facing the sealed liquid has a large thermal expansion coefficient. In this case, the rubber lip is formed of, for example, two kinds of rubber lip materials, and the atmosphere side thereof is It is preferable to back up with a synthetic resin lip.

[Operation] That is, according to the present invention, with the above configuration,
The rubber lip is formed by laminating multiple types of rubber lip materials with different thermal expansion coefficients, and the lip material facing the sealing liquid has a large thermal expansion coefficient. When the temperature of the rubber lip rises due to the temperature rise of, the expansion of the outer lip material facing the sealing liquid side is large and the expansion of the inner lip material is small, and the difference between them becomes large. The surface pressure at the tip of the lip maintains a stable state, wear of the rotating shaft is prevented, and
Even at a low temperature such as when the operation is stopped, since the tip of the lip is not bent so much, the tightening force with the rotary shaft is increased, whereby a stable sealing property is obtained.

[Embodiment] The present invention will be described below with reference to an embodiment shown in FIGS. 1 and 3. In the illustrated embodiment according to the present invention, the same reference numerals are used for the portions that have the same construction as the lip type seal having the conventional structure shown in FIG.

That is, according to the present invention, as shown in FIG. 1, a rubber lip (1) backed up by a synthetic resin lip (2).
Are laminated with a first rubber lip material (11) and a second rubber lip material (12) having different thermal expansion coefficients from each other, and the outer first surface facing the sealing liquid side (B) is formed. The first rubber lip material (11) has a larger thermal expansion coefficient than that of the second rubber lip material (12) on the inner side. As a result, as shown in FIG. , The first lip material (11) facing the sealed liquid side (B) when the temperature of the rubber lip (1) rises during operation
Of the second lip material (12) is small and the difference between them is large, and the surface pressure of the lip tip (1a) to the rotating shaft (S) is always maintained in a stable state. .

Further, even at a low temperature such as when the operation is stopped, since the bending of the lip tip portion (1a) is small, the rotating shaft (S)
The tightening force with and becomes large, and thereby stable sealing performance is maintained.

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[Effects of the Invention] As is apparent from the above description, according to the present invention, a rubber lip whose tip end is in sliding contact with the circumference of the rotating shaft is provided with a plurality of types of rubber lips having different thermal expansion coefficients. Because the lip material facing the sealing liquid side is laminated and made to have a large thermal expansion coefficient, the temperature of the sealing liquid increases with the rotation of the rotating shaft, and the temperature of the rubber lip rises. However, the expansion of the outer lip material facing the sealing liquid side is large, the expansion of the inner lip material is small, and the difference is large, so the surface pressure of the lip tip to the rotating shaft is always stable It can be maintained at a high level, prevents wear of the rotary shaft, and has little bending of the lip tip even at low temperature such as when operation is stopped. , By this, stable sealing property It has an excellent effect of being able to obtain.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of an essential part showing an embodiment of a lip-type seal according to the present invention, FIG. 2 is an explanatory view showing a surface pressure state of a rubber lip against a rotating shaft at a high temperature, and FIG. FIG. 4 is a schematic explanatory view of a main part of a conventional lip-type seal. (S) ... Rotary shaft, (1) ... Rubber lip, (1a) ... Lip tip, (11) ... First rubber lip material, (12) ... Second rubber lip Material, (2) …… Synthetic resin lip, (A) …… Atmosphere side, (B) …… Seal fluid side.

Claims (2)

[Scope of utility model registration request] 1. A lip material which is formed by laminating a plurality of kinds of rubber lip materials having different thermal expansion coefficients from each other, and a rubber lip whose tip is slidably contacted with the circumference of a rotary shaft, and which faces the sealing liquid side. A lip-type seal characterized by having a large coefficient of thermal expansion. 2. The lip-type seal according to claim 1, wherein the rubber lip is formed of two kinds of rubber lip materials, and the atmosphere side thereof is backed up by a synthetic resin lip.