JP2017207107A - Seal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of a grease retaining function caused by abrasion of a satin 133 formed on an inner peripheral surface of a sub lip part 132 of a seal lip 13 and achieve improvement of durability of the seal lip 13.SOLUTION: A seal device includes a seal lip 13 which is integrally provided with a reinforcement ring 11 and formed by a rubber elastic body. A main lip part 131, which tightly contacts with an outer peripheral surface of a rotor 3 in a slidable manner, and a sub lip part 132, which is positioned closer to a root 13a side of the seal lip 13 than the main lip part 131 and may contact with the outer peripheral surface of the rotor 3, are formed on an inner peripheral surface of the seal lip 13. A second reinforcement ring 16 positioned at an outer periphery of the sub lip part 132 and fixed to the reinforcement ring 11 is embedded in the seal lip 13.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sealing device that has a sealing lip and is used, for example, as a sealing means around a rotating shaft in a power steering device of an automobile.

  2. Description of the Related Art Conventionally, for example, a sealing device as shown in FIG. 2 is known as a sealing device that seals the outer periphery of a rotating shaft with a sealing lip in an automobile power steering device or the like. That is, this type of sealing device 100 includes a fixed seal portion 102 that is tightly fitted to the inner peripheral surface of the housing 200, and a seal lip 103 and a dust lip 104 that are slidably in close contact with the outer peripheral surface of the rotary shaft 300. A rubber elastic body is integrally formed with the metal reinforcing ring 101 to compensate the tight force of the seal lip 103 on the outer periphery of the seal lip 103 and to ensure the radial followability of the seal lip 103 with respect to the rotary shaft 300. The garter spring 105 is fitted.

  On the inner peripheral surface of the seal lip 103, a main lip portion 103a and a sub lip portion 103b positioned on the base side thereof are formed. Then, when the rotary shaft 300 is displaced in the radial direction by swinging, the secondary lip 103b prevents the internal peripheral surface of the secondary lip portion 103b from sticking to the outer peripheral surface of the rotary shaft 300 and generating noise. A satin finish 103c for holding grease is formed on the inner peripheral surface of the portion 103b, thereby improving the lubricity of the outer peripheral surface of the rotating shaft 300.

  The sealing device 100 configured as described above is sealed by the main lip portion 103a of the seal lip 103 facing the sealed space A side (right side in FIG. 2) being slidably in contact with the outer peripheral surface of the rotary shaft 300. The oil to be sealed in the space A is prevented from leaking into the atmosphere B on the left side in FIG. 2 from the shaft circumference, and the dust lip 104 prevents intrusion of muddy water, dust, etc. from the atmosphere B side. Yes (see, for example, Patent Document 1 below).

JP 2002-139156 A

  However, according to the conventional sealing device 100, the seal lip 103 is subjected to a diameter reduction deformation due to a pressure increase in the sealed space A, a radial displacement of the rotary shaft 300, or the like, and the inner peripheral surface of the sub lip portion 103b is the rotary shaft. If the outer peripheral surface of 300 is repeatedly applied to the solid surface, the wear of the sub lip portion 103b is likely to proceed, and there is a concern that the grease holding function of the sub lip portion 103b may be impaired over time.

  The present invention has been made in view of the above points, and its technical problem is to prevent the grease retaining function from being deteriorated due to wear of the auxiliary lip portion and to improve the durability of the seal lip. It is in.

  In order to solve the technical problem described above, a sealing device according to the invention of claim 1 includes a seal lip made of a rubber elastic body provided integrally with a reinforcing ring, and a rotating body on the inner peripheral surface of the seal lip. A main lip portion slidably in contact with the outer peripheral surface of the seal lip, and a sub lip portion which is located on the root side of the seal lip from the main lip portion and can contact the outer peripheral surface of the rotating body In the apparatus, the seal lip is embedded with a second reinforcing ring located on the outer periphery of the sub lip portion and fixed to the reinforcing ring.

  A sealing device according to a second aspect of the invention is characterized in that, in the configuration of the first aspect, minute irregularities for retaining a lubricant are formed on the inner peripheral surface of the sub lip portion.

  According to the sealing device of the present invention, the second lip portion is embedded in the seal lip at the outer periphery of the sub lip portion, thereby increasing the rigidity of the sub lip portion and increasing the pressure in the sealed space. Even if the rotator is displaced in the radial direction, the inner peripheral surface of the sub lip portion is less likely to stick to the outer peripheral surface of the rotator, so that the wear of the sub lip portion is suppressed, resulting in the durability of the seal lip. Can be improved.

It is sectional drawing which cuts and shows preferable embodiment of the sealing device which concerns on this invention by the plane which passes along an axial center. It is sectional drawing which cuts and shows an example of the conventional sealing device by the plane which passes along an axial center.

  Hereinafter, a preferred embodiment of a sealing device according to the present invention will be described in detail with reference to FIG.

  A sealing device 1 according to the embodiment shown in FIG. 1 is fixedly fitted to an inner peripheral surface of a housing 2 in a power steering device or the like of an automobile, and is rotatable and swingable on the inner periphery of the housing 2. A seal lip 13 and a dust lip 14 slidably brought into close contact with the outer peripheral surface of the inserted rotating shaft 3 are attached to a metal reinforcing ring 11 by a rubber-like elastic body (rubber or synthetic resin having rubber-like elasticity). The seal lip 13 has a structure in which a garter spring 15 is mounted on the outer periphery of the seal lip 13 and a second reinforcing ring 16 is embedded in the seal lip 13. The rotating shaft 3 corresponds to the rotating body described in claim 1.

  The reinforcing ring 11 includes a cylindrical portion 11a, and an inward flange portion 11b that extends and bends from an end portion of the cylindrical portion 11a opposite to the sealed space A to the inner diameter side.

  The fixed seal portion 12 is press-fitted and fixed to the inner peripheral surface of the housing 2, and is provided so as to cover the outer peripheral surface of the cylindrical portion 11 a in the reinforcing ring 11.

  The seal lip 13 is continuous with the fixed seal portion 12 through the intermediate portion 17 that has been turned from the fixed seal portion 12 to the inner peripheral side of the cylindrical portion 11a of the reinforcing ring 11, and from the inner diameter portion of the intermediate portion 17, It extends in the direction (the right side in FIG. 1) which becomes the sealed space A side in the mounted state.

  On the inner peripheral surface of the seal lip 13, a main lip portion 131 that is slidably in contact with the outer peripheral surface of the rotating shaft 3 with an appropriate tightening margin, and on the root 13 a side of the seal lip 13 from the main lip portion 131. A sub lip portion 132 is formed which can be positioned and abutted against the outer peripheral surface of the rotary shaft 3.

  A satin finish 133 is formed on the inner peripheral surface of the sub lip 132 in the seal lip 13, and this satin finish 133 is not formed in the process of vulcanization molding of the fixed seal portion 12, the seal lip 13, the dust strip 14, and the like. It is formed by a rough surface formed on the molding surface of the sub lip portion in the mold shown in the figure, and is composed of innumerable minute irregularities.

  The dust lip 14 is continuously vulcanized and bonded to the inner diameter end of the inward flange portion 11b of the reinforcing ring 11 continuously with the root 13a of the seal lip 13, and is opposite to the seal lip 13, that is, on the left side (atmosphere) in FIG. B side).

  The garter spring 15 is formed by connecting long metal coil springs in an annular shape, and is fitted into an annular groove 13 b formed on the outer peripheral side of the main lip portion 131 of the seal lip 13. This is to compensate for the decrease in the tightening force with time due to the settling, and to ensure the radial followability of the main lip portion 131 with respect to the rotating shaft 3.

  The second reinforcing ring 16 is made of metal or synthetic resin, and is embedded in the seal lip 13 at a position from the vicinity of the root 13a to the outer periphery of the sub lip 132, and the inward flange portion of the reinforcing ring 11 It fits in the annular recessed part 11c formed in the surface by the side of the seal lip 13 in the inner diameter end of 11b.

  The second reinforcing ring 16 has a cross-sectional shape in which an end portion 16a opposite to the inner diameter end of the inward flange portion 11b of the reinforcing ring 11 is thin in the radial direction, and the attachment position of the garter spring 15 The shape does not reach. As a result, the radial followability of the main lip 131 of the seal lip 13 with respect to the radial displacement caused by the swinging of the rotary shaft 3 or the like is ensured.

  The sealing device 1 configured as described above is preliminarily provided on the inner peripheral surface between the main lip portion 131 of the seal lip 13 and the dust lip 14 for the purpose of lubricating the seal lip 13 and the dust lip 14 with respect to the rotary shaft 3. A grease (not shown) is applied. The grease corresponds to the lubricant recited in claim 2.

  The fixed seal portion 12 is press-fitted into the inner peripheral surface of the housing 2 so that the seal lip 13 faces the sealed space A, and the main lip portion 131 of the seal lip 13 slides on the outer peripheral surface of the rotary shaft 3. By being in close contact with each other, the oil to be sealed in the sealed space A is prevented from leaking from the shaft periphery to the atmosphere B side, and the dust lip 14 is slidably contacted with the outer peripheral surface of the rotating shaft 3. This prevents muddy water or dust on the atmosphere B side from entering the seal lip 13 side.

  For this reason, in the mounted state, sufficient grease is interposed between the valley portion 13 c between the main lip portion 131 and the sub lip portion 132 of the seal lip 13 and the outer peripheral surface of the rotary shaft 3. A part of the grease intervenes in sliding portions between the main lip portion 131 and the sub lip portion 132 and the outer peripheral surface of the rotating shaft 3 as the rotating shaft 3 rotates, so that a lubricating film is formed. 3 has good lubricity to the outer peripheral surface. Moreover, the satin fabric 133 formed on the inner peripheral surface of the sub lip portion 132 also becomes an infinite number of fine grease reservoirs and forms a thick lubricating layer, whereby the sub lip portion 132 is lubricated better.

  Even if the pressure of the oil to be sealed in the sealed space A rises and a deformation force in the diameter reducing direction acts on the seal lip 13, the sub lip 132 is applied to the seal lip 13 from the vicinity of the root 13 a. Since the second reinforcing ring 16 located on the outer periphery of the seal lip 13 is embedded, at least the portion from the vicinity of the root 13a to the sub lip portion 132 is not subjected to large diameter deformation due to the pressure. Solid contact of the inner peripheral surface of the sub lip part 132 with respect to the outer peripheral surface of the rotating shaft 3 is suppressed. Accordingly, the matte surface 133 formed on the inner peripheral surface of the sub lip portion 132 is not easily worn, and the grease retaining function by the matte surface 133 is maintained over a long period of time, so that insufficient lubrication is effectively prevented.

  Further, even if an uneven load is applied to the seal lip 13 due to the radial behavior caused by the swinging of the rotating shaft 3, as described above, the seal lip 13 is at least a portion from the vicinity of the root 13a to the sub lip 132. Is reinforced by the second reinforcing ring 16 and has high rigidity, so that the solid contact of the inner peripheral surface of the sub lip portion 132 with respect to the outer peripheral surface of the rotating shaft 3 is suppressed. Accordingly, in this case as well, the matte surface 133 formed on the inner peripheral surface of the auxiliary lip portion 132 is not easily worn, and the grease retaining function by the matte surface 133 is maintained over a long period of time, so that insufficient lubrication is effectively prevented. The durability of the lip 13 can be improved.

  The cross-sectional shape of the second reinforcing ring 16 is not limited to that shown in the drawing, and can be changed as appropriate according to the specifications of the seal lip 13.

DESCRIPTION OF SYMBOLS 1 Sealing device 11 Reinforcement ring 13 Seal lip 131 Main lip part 132 Sub lip part 133 Satin (micro unevenness)
14 Dustrip 16 Second reinforcing ring 2 Housing 3 Rotating shaft (Rotating body)

Claims (2)

  A seal lip made of a rubber elastic body provided integrally with the reinforcing ring, and a main lip portion that is slidably in contact with an inner peripheral surface of the seal lip and an outer peripheral surface of the rotating body; In the sealing device in which a sub lip portion formed on the base side of the seal lip and capable of contacting the outer peripheral surface of the rotating body is formed, the seal lip is positioned on the outer periphery of the sub lip portion, and the reinforcing ring A sealing device characterized in that a second reinforcing ring fixed to the pad is embedded.   The sealing device according to claim 1, wherein minute irregularities for retaining the lubricant are formed on the inner peripheral surface of the sub lip portion.

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