JP2009222184A - Seal structure for universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seal structure capable of securing smooth joint operation by restraining the occurrence of a sucking phenomenon by pressure fluctuation, without making pressure slipped out to the outside a joint, even if the pressure (internal pressure) is generated in the joint by a temperature change. <P>SOLUTION: This seal structure is used for a universal joint having a spider 2, a cup 3 for surrounding the end outer periphery of the spider 2 and a bearing 4 interposed between the spider 2 and the cup 3, and has a seal lip 5. An inside seal 10 such as a lip shape or a projection shape of sealing the internal pressure by being slidably brought into close contact with a peripheral surface 2a of the spider 2 is arranged at a tip of an inward flange 3a in the cup 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a seal structure, and more particularly to a seal structure for a universal joint used for a universal joint used for a steering joint, a propeller shaft, or the like of a vehicle such as an automobile.

  2. Description of the Related Art Conventionally, a universal joint shown in FIG. 5 is known as a universal joint used for a steering joint, a propeller shaft, and the like of a vehicle such as an automobile. The universal joint 1 includes a cup 3 surrounding an outer periphery of an end portion of the spider 2 and spider 2. A bearing 4 interposed between the spider 2 and the cup 3 is provided, and a lip seal 5 is provided as a universal joint seal for sealing dust such as grease inside the joint and outside muddy water.

  As shown in an enlarged view in FIG. 6, the lip seal 5 is provided integrally with the fixing portion 6 fixed to the spider 2 and the fixing portion 6, and slides on the end surface of the inward flange portion 3 a at the tip of the cup 3. A seal lip 7 that is movably in close contact, and a dust lip 8 that is disposed on the outer peripheral side of the seal lip 7 and is provided integrally with the fixed portion 6 and slidably close to the cup 3 are provided ( Patent Document 1).

  In the lip seal 5 shown in FIG. 6, the seal lip 7 has an inwardly-shaped seal lip that is in close contact with the end surface of the inward flange portion 3a at the tip of the cup 3 with the lip end facing inward in the radial direction. However, as another prior art, as shown in FIG. 7, the outward shape is in close contact with the end face of the inward flange portion 3a at the tip of the cup 3 with the lip end of the seal lip 7 facing radially outward. Some of them are used as seal lips (see Patent Document 2).

  When comparing the inwardly-shaped seal lip 7 of FIG. 6 and the outwardly-shaped seal lip 7 of FIG. 7, the outward-shaped seal lip 7 of FIG. 7 has the advantage that the bending torque can be reduced. However, the seal structure provided with the outwardly-shaped seal lip 7 of FIG. 7 has the following disadvantages.

  In other words, if the seal structure is set to a universal joint and heat is generated during operation (due to sliding heat generated by the seal lip or peripheral equipment (exhaust pipe, etc.)), pressure (internal pressure) is generated inside the joint (inside the cup 3). ) Occurs, and the generated internal pressure acts as a back pressure on the outwardly-shaped seal lip 7. After that, when cooled, the inside of the joint is under negative pressure, so a suction phenomenon occurs. If water (muddy water, ice, etc.) adheres to the joint, this water is sucked into the joint along with air. There is a risk of hindering smooth joint operation. In addition, the lip contact state may become unstable due to the influence of pressure.

JP 2000-110846 A JP 2001-146924 A

  In view of the above points, the present invention can suppress the occurrence of a suction phenomenon due to pressure fluctuations, even if a pressure (internal pressure) is generated inside the joint due to a temperature change or the like. An object of the present invention is to provide a seal structure that can ensure a smooth joint operation.

  In order to achieve the above object, a seal structure according to claim 1 of the present invention is a seal used for a universal joint having a spider, a cup surrounding an outer periphery of an end of the spider, and a bearing interposed between the spider and the cup. And a lip seal interposed between the spider and the cup outside the bearing, the lip seal being fixed to the spider and provided integrally with the fixed portion. A seal lip that is slidably in close contact with the end face of the inward flange portion at the tip of the cup, and is disposed on the outer peripheral side of the seal lip and is provided integrally with the fixing portion and is slidable on the cup A dust strip that is in close contact with the inner surface of the spider. It is characterized in that the closely internal pressure is provided inside the seal to seal the.

  The seal structure according to claim 2 of the present invention is the seal structure according to claim 1, wherein the lip end of the seal lip that is slidably in close contact with the end face of the inward flange portion at the tip of the cup in the lip seal has a lip end. An outwardly facing seal lip that is in close contact with the end surface of the flange portion in a state of being directed radially outward, or an inward shape that is in close contact with the end surface of the flange portion in a state of being directed radially inward It is characterized by being a seal lip.

  In the present invention having the above-described configuration, an internal seal is provided as a third seal located further inside the dust lip and the seal lip so as to be slidably in close contact with the peripheral surface of the spider and seal the internal pressure. For this reason, the internal pressure is not easily released to the outside of the joint by the sealing action of the internal seal.

  Further, in the present invention, the internal seal that performs the above-described action is provided at the tip of the inward flange portion of the cup and is slidably in close contact with the peripheral surface of the spider, and the tip of the inward flange portion Since the radial interval is set small between the peripheral surface of the part and the spider, the internal seal also has a small height dimension (internal / external diameter difference). In the case of a seal having a small height dimension, the rigidity can be set higher than that of a normal seal lip, so that the internal pressure is difficult to escape to the outside of the joint.

  Further, the shape of the internal seal is preferably a lip shape or a protrusion shape as a shape that allows the pressure inside the joint to be released when the joint is assembled (a shape that does not enclose pressure).

  The lip seal combined with the internal seal is a lip seal having the outwardly-shaped seal lip, but even if the lip seal has an inward-shaped seal lip, the release of internal pressure is not zero. The effect is recognized. Therefore, in the present invention, the direction of the seal lip is not limited, and this is confirmed in claim 2.

  The present invention has the following effects.

  That is, in the present invention, an internal seal is provided as a third seal located further inside the dust lip and the seal lip so as to be slidably in close contact with the peripheral surface of the spider and seal the internal pressure. The internal pressure prevents the internal pressure from coming out of the joint due to the sealing action of the internal seal. If the internal pressure is difficult to escape, it is possible to suppress the occurrence of a suction phenomenon when the temperature is lowered, and thus to suppress the water in the vicinity of the joint from being sucked into the joint and hindering the smooth joint operation. Further, since the seal lip is not subjected to pressure, unstable contact is not caused.

  Further, in the present invention, the internal seal that performs the above-described action is provided at the tip of the inward flange portion of the cup and is slidably in close contact with the peripheral surface of the spider, and has a small height dimension. Therefore, the rigidity can be set higher than that of a normal seal lip, and the internal pressure is difficult to escape to the outside of the joint.

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

  FIG. 1 shows a cross section of the main part of a seal structure according to an embodiment of the present invention. The right side of the figure is the inner peripheral side and the left side is the outer peripheral side, but the seal structure is upside down for convenience of drawing as compared to FIGS. 6 and 7 according to the conventional example.

  The seal structure according to the embodiment is used as a universal joint seal or a propeller shaft seal for a universal joint used for a steering joint, a propeller shaft or the like in a vehicle such as an automobile.

  The universal joint is provided with a spider 2, a cup 3 surrounding the outer peripheral side of the end of the spider 2, and a bearing (needle bearing) 4 interposed between the spider 2 and the cup 3. A lip seal 5 is provided as a universal joint seal for sealing dust such as external muddy water. The cup 3 integrally has an inward flange portion 3a at the tip of the cylindrical portion 3b. The lip seal 5 is formed integrally with the fixed portion 6 and the annular fixed portion 6 fixed (fitted) to the step portion of the spider 2, and is slidable on the end surface of the inward flange portion 3a at the tip of the cup 3. And a dust lip 8 which is disposed on the outer peripheral side of the seal lip 7 and is integrally formed with the fixed portion 6 so as to be slidably in contact with the root portion of the inward flange portion 3a at the tip of the cup 3. And are provided. A reinforcing ring 9 having a U-shaped cross section is embedded in the fixed portion 6. The seal lip 7 is an outwardly-shaped seal lip that is in close contact with the end surface of the flange portion 3a in a state where the lip end 7a faces radially outward.

  Further, in this embodiment, an inner seal 10 is provided at the tip of the inward flange portion 3a of the cup 3, that is, the inner diameter surface so as to be slidably in close contact with the peripheral surface 2a of the spider 2 and seal the internal pressure. . The inner seal 10 is formed of a predetermined rubber-like elastic body, is vulcanized and bonded to the tip portion of the flange portion 3a, that is, the inner diameter surface, and is formed as a lip shape. The direction of the lip is such that the pressure inside the joint is released when the joint is assembled (the direction in which the pressure is not sealed), that is, the lip end is away from the bearing 4 inside the joint.

  In the seal structure having the above-described configuration, an internal seal 10 is provided as a third seal located further inside the dust lip 8 and the seal lip 7 and slidably in close contact with the peripheral surface 2a of the spider 2 to seal the internal pressure. Therefore, the internal pressure generated inside the joint is not easily released to the outside of the joint by the sealing action of the internal seal 10. If it is difficult to release the internal pressure inside the joint, it is possible to suppress the occurrence of a suction phenomenon when the temperature drops, and thus it is possible to suppress the water in the vicinity of the joint from being sucked into the joint and hindering smooth joint operation. . Further, since the seal lip 7 is not directly subjected to pressure, unstable contact is not caused.

  Further, in the above configuration, the internal seal 10 that performs the above-described action is provided at the tip of the inward flange portion 3a in the cup 3, that is, the inner diameter surface, and is slidably in close contact with the peripheral surface 2a of the spider 2. Therefore, the inner seal 10 has a small height, and therefore the rigidity of the inner seal 10 can be set higher than that of a normal seal lip, and the internal pressure does not easily escape to the outside of the joint.

  In the above embodiment, the inner seal 10 has a lip shape. However, the inner seal 10 is not particularly limited as long as the pressure inside the joint can be released when the joint is assembled (no pressure is sealed). For example, the protrusion shape shown in FIG. There may be. The inner seal 10 in FIG. 2 has a projection having a triangular cross section in close contact with the peripheral surface 2a of the spider 2 at the top.

  Moreover, in the said Example, although the lip seal 5 combined with the internal seal 10 shall be equipped with the outward-shaped seal lip 7, it is provided with the inward-shaped seal lip 7 as shown in FIG. 3 or FIG. It is also good. In the example of FIG. 3, the same lip-shaped internal seal 10 as that of the above-described embodiment (FIG. 1) is provided. In the example of FIG. 4, an internal seal 10 having the same protruding shape as that of the example of FIG. 2 is provided.

Sectional drawing of the principal part of the seal structure for universal joints based on the Example of this invention. Sectional drawing of the principal part of the seal structure for universal joints which concerns on the other Example of this invention. Sectional drawing of the principal part of the seal structure for universal joints which concerns on the other Example of this invention. Sectional drawing of the principal part of the seal structure for universal joints which concerns on the other Example of this invention. Illustration of universal joint Cross section of the main part of the universal joint seal according to the conventional example Cross-sectional view of main parts of a universal joint seal according to another conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Universal joint 2 Spider 2a Circumferential surface 3 Cup 3a Inward flange part 3b Cylindrical part 4 Bearing 5 Lip seal 6 Fixed part 7 Seal lip 7a Lip end 8 Dustrip 9 Reinforcement ring 10 Internal seal

Claims (2)

A seal structure used for a universal joint having a spider, a cup surrounding an outer periphery of an end portion of the spider, and a bearing interposed between the spider and the cup,
A lip seal interposed between the spider and the cup on the outside of the bearing, the lip seal being fixed to the spider and integrally provided in the fixed portion; A seal lip that is slidably in close contact with the end face of the inward flange portion, and a dust lip that is disposed on the outer peripheral side of the seal lip and is provided integrally with the fixing portion and slidably in close contact with the cup And integrally
A seal structure for a universal joint, wherein an inner seal that seals an internal pressure is provided at a distal end portion of an inward flange portion of the cup so as to be slidably in contact with a peripheral surface of the spider. The seal structure according to claim 1,
The seal lip that is slidably in close contact with the end face of the inward flange portion at the tip of the cup in the lip seal is an outwardly-shaped seal lip that is in close contact with the end surface of the flange portion with the lip end facing radially outward. Or a seal lip for a universal joint, wherein the seal lip is an inwardly-shaped seal lip that is in close contact with the end face of the flange portion with the lip end facing radially inward.

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