JP2005273693A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device capable of compatibly establishing reduction of torque and sealing performance. <P>SOLUTION: This device includes a seal lip 8 sealing sealed fluid and a screw pump mechanism 9 arranged on an outside of the seal lip 8. The screw pump mechanism 9 demonstrates fluid pumping action toward the seal lip 8 to reduce tightening force of the seal lip 8. A rubber like elastic body 6 is attached on a metal ring 5 fitted in an inner circumference of a spindle hole 3 of the housing 2, and the seal lip 8 slidably put close to a circumference surface of a spindle 4 and a cylindrical part 10 arranged on an outside of the seal lip 8 and provided with a cylindrical surface 10a facing the circumference surface 4a of the spindle 4 are formed as one piece by the rubber like elastic body 6. A screw 11 of the screw pump mechanism 9 is provided on the cylindrical surface 10a of the cylindrical part 10 or the circumference surface 4a of the spindle 4 facing the same. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sealing device. The sealing device of the present invention is used, for example, in the field related to automobiles or other general industrial machines.

  As shown in FIG. 3, the sealing device 51 previously proposed by the applicant of the present application has a seal lip 52, and is slidably in close contact with the peripheral surface of the shaft 53 on the atmosphere A side of the seal lip 52. A lip end 54 is provided, and a screw 55 of a screw pump mechanism that performs a fluid pumping action when the shaft 53 rotates is provided on the sealed fluid B side. When the shaft 53 rotates, the screw 55 performs a pumping action in a direction in which the sealing fluid B is pushed back (arrow direction in the figure).

  The sealing device 51 having the above-described configuration is configured to perform a sealing function by simultaneously performing a sealing action by interference and a sealing action by pumping with one seal lip 52. In the sealing device 51, the torque of the seal lip 52 is reduced by a method of reducing the tension (reducing the surface pressure) by reducing the cross section of the seal lip 52.

  However, the sealing device 51 having the above configuration has room for further improvement in the following points.

  That is, in the sealing device 51 configured as described above, it is necessary to secure the minimum surface pressure of the seal lip 52 in order to ensure the sealing performance. There is a limit to the compatibility between sealing and sealing. As a drawback due to a decrease in the surface pressure, there is a concern about a decrease in eccentricity following a low temperature and a decrease in sealing performance.

JP 2002-174346 A

  An object of this invention is to provide the sealing device which can make low torque and sealing performance compatible in view of the above point.

  In order to achieve the above object, a sealing device according to claim 1 of the present invention includes a seal lip for sealing a sealing fluid, and a screw pump mechanism disposed outside the seal lip, and the screw pump mechanism includes the seal lip. It is characterized in that it exerts a fluid pumping action toward the lip to substantially reduce the tightening force of the seal lip.

  The sealing device according to claim 2 of the present invention is the sealing device according to claim 1, wherein a rubber-like elastic body is attached to a metal ring fitted to the inner periphery of the shaft hole of the housing. The body integrally forms a seal lip that is slidably in close contact with the peripheral surface of the shaft, and a cylindrical portion that is disposed outside the seal lip and has a cylindrical surface that faces the peripheral surface of the shaft. The screw of the screw pump mechanism is provided on the cylindrical surface of the cylindrical portion or the peripheral surface of the shaft opposed to the cylindrical surface.

  According to a third aspect of the present invention, in the sealing device according to the first or second aspect, the screw of the screw pump mechanism is provided on the peripheral surface of the shaft.

  The present invention has the following effects.

  That is, in the sealing device according to the first aspect of the present invention having the above-described configuration, the sealing lip performs a sealing function to seal the sealing fluid, and the screw pump mechanism disposed outside the sealing lip is provided on the sealing lip. It serves as a fluid pumping action and substantially reduces the tightness of the seal lip. Therefore, since the sealing action portion and the pumping action portion are clearly divided in function in this way, the sealing performance is ensured by the former sealing lip, and the torque of the sealing lip is reduced by the latter screw pump mechanism. Can do.

  According to the second aspect of the present invention, the seal lip that is slidably in close contact with the peripheral surface of the shaft and forms a sealing function, and the cylindrical portion that is combined with the shaft to form the screw pump mechanism are integrally formed with each other. The two oil seals can constitute a sealing device that achieves the operational effects of the first aspect.

  In the first or second aspect, the screw of the screw pump mechanism may be provided on the cylindrical surface of the cylindrical portion, or may be provided on the peripheral surface of the shaft facing the cylindrical surface of the cylindrical portion. In the case where it is provided on the peripheral surface of the latter shaft, a large pumping force can be generally obtained because it is not subject to the restriction of the thread groove opening cross-sectional area. Therefore, if the screw of the screw pump mechanism is provided on the peripheral surface of the shaft as in claim 3, a sealing device that exhibits a relatively large pumping force can be configured.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a half-cut section of a sealing device 1 according to an embodiment of the present invention. The sealing device 1 according to this embodiment is mounted on the inner periphery of the shaft hole 3 of the housing 2 and is slidably in close contact with the peripheral surface 4a of the shaft 4 to seal the sealing fluid B such as lubricating oil. The configuration is as follows.

  That is, first, a metal ring 5 fitted to the inner periphery of the shaft hole 3 of the housing 2 is provided, and a rubber-like elastic body 6 is vulcanized and bonded to the metal ring 5. The rubber-like elastic body 6 is slidably in close contact with the outer peripheral seal portion 7 that seals the sealing fluid B by being radially compressed between the metal ring 5 and the housing 2, and is slidably in close contact with the peripheral surface 4 a of the shaft 4. The seal lip 8 that seals the fluid B and the cylindrical portion 10 that is disposed outside the seal lip 8 (at the atmosphere A side) and that faces the peripheral surface 4a of the shaft 4 and forms the screw pump mechanism 9 are integrally formed. The screw 11 of the screw pump mechanism 9 is provided on the peripheral surface 4a of the latter shaft 4 among the cylindrical surface 10a of the cylindrical portion 10 and the peripheral surface 4a of the shaft 4 that are opposed to each other in the radial direction. The screw pump mechanism 9 performs a fluid pumping action in the direction of the arrow in the figure toward the seal lip 8 when the shaft 4 rotates, and reduces the tension of the seal lip 8.

  In the sealing device 1 configured as described above, the seal lip 8 functions as a seal to seal the sealing fluid B as described above, and the screw pump mechanism 9 disposed outside the seal lip 8 is directed toward the seal lip 8. Thus, it functions to reduce the tension of the seal lip 8 by performing a fluid pumping action. The reason why the tightening force decreases is that the atmospheric pressure of the seal lip 8 is increased by the fluid pumping action of the screw pump mechanism 9. Therefore, since the sealing action part and the pumping action part are clearly divided into functions, the sealing performance is secured by the former seal lip 8 and the torque of the sealing lip 8 is reduced by the latter screw pump mechanism 9. Therefore, the sealing device 1 that can achieve both low torque and sealing performance can be provided as intended.

  Further, as shown in the drawing, since the entire sealing device 1 is configured as a one-piece oil seal, it is possible to provide the sealing device 1 that is easy to handle such as manufacture, transportation, storage, and detachment.

  Further, since the screw 11 of the screw pump mechanism 9 is provided on the peripheral surface 4a of the shaft 4 that is not limited by the size of the cross-sectional area of the screw groove opening, the sealing device 1 that exhibits a relatively large pumping force is provided. be able to.

  In the above-described embodiment, a radial clearance c having a predetermined size is set between the cylindrical surface 10a of the cylindrical portion 10 and the peripheral surface 4a of the shaft 4 facing the cylindrical surface 10a. The ten cylindrical surfaces 10a may be configured to slidably contact the peripheral surface 4a of the shaft 4. However, in this case, in order to reduce the torque, the cylindrical surface 10a of the cylindrical portion 10 is subjected to a coating process, or the sliding ring 12 is attached to the cylindrical surface 10a as shown in FIG. The material of the mounting ring 12 is preferably a resin material having wear resistance and low friction characteristics, such as polytetrafluoroethylene (PTFE).

Sectional drawing of the half-section of the sealing device based on the Example of this invention Half-cut sectional view of a sealing device according to another embodiment of the present invention Explanatory drawing of the sealing device which concerns on a prior art example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing device 2 Housing 3 Shaft hole 4 Shaft 4a Circumference surface 5 Metal ring 6 Rubber-like elastic body 7 Outer periphery seal part 8 Seal lip 9 Screw pump mechanism 10 Cylindrical part 10a Cylindrical surface 11 Screw 12 Sliding ring A Atmosphere side B Sealing fluid Side c Radial clearance

Claims (3)

A seal lip (8) for sealing a sealing fluid, and a screw pump mechanism (9) disposed outside the seal lip (8),
The sealing device according to claim 1, wherein the screw pump mechanism (9) performs a fluid pumping action toward the seal lip (8) to substantially reduce a pressing force of the seal lip (8). The sealing device of claim 1.
A rubber-like elastic body (6) is attached to a metal ring (5) fitted to the inner periphery of the shaft hole (3) of the housing (2), and the rubber-like elastic body (6) causes the shaft (4). A seal lip (8) that is slidably in close contact with the peripheral surface (4a), and a cylindrical surface (10a) that is disposed outside the seal lip (8) and faces the peripheral surface (4a) of the shaft (4). The cylindrical portion (10) provided is integrally molded,
A sealing device, wherein a screw (11) of a screw pump mechanism (9) is provided on a cylindrical surface (10a) of the cylindrical portion (10) or a peripheral surface (4a) of a shaft (4) opposed to the cylindrical surface (10a). The sealing device according to claim 1 or 2,
A sealing device, wherein a screw (11) of a screw pump mechanism (9) is provided on a peripheral surface (4a) of a shaft (4).

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