Patent Application
20120256342
The disclosure of Japanese Patent Application No. 2011-085182 filed on Apr. 7, 2011 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
The invention relates to a method of producing a seal member.
2. Description of the Related Art
A known example of a seal member used in a rolling bearing device for a wheel, for example, for sealing an annular space between an inner ring member and an outer ring member includes a fixed portion fixed to an inner periphery of the outer ring member, and a lip that is in sliding contact with the vicinity of a raceway shoulder portion of the inner ring member.
In the seal member as described above, if two or more lips are formed, or the elastic force of the lip(s) is increased so as to enhance the sealing performance, the sliding resistance increases, resulting in an adverse influence on the fuel efficiency and significant wear of the lip(s).
Under the circumstances, a sealed rolling bearing as disclosed in Japanese Patent Application Publication No. 2004-19779 (JP 2004-19779 A), for example, is known as having an arrangement for reducing wear of a lip of a seal member.
In the sealed rolling bearing containing a lubricant, as disclosed in JP 2004-19779 A, a seal member (sealing plate) attached to one bearing ring is provided with a lip (lip portion) that abuts on and slides on the other bearing ring, and a sliding surface of the lip that is in sliding contact with the other bearing ring is formed with minute projections and recesses.
To form the minute projections and recesses on/in the surface of the lip of the seal member in the rolling bearing of JP 2004-19779A, a large number of pimple-like protrusions opposite in shape to a large number of dimple-like recesses are formed in advance, by an electric discharge machine, or the like, on a portion of a surface of a mold used in cure molding, the portion corresponding to the sliding surface and its surrounding, and a rubber material of the seal member is shaped under pressure during cure molding, to follow the shape of the projections, so that the lip is formed at its surface with the minute projections and recesses during molding of the seal member.
It is possible to reduce the sliding resistance by forming the minute projections and recesses on/in the surface of the lip of the seal member, as disclosed in JP 2004-19779 A.
However, a large number of pimple-like protrusions have to be formed on the molding surface of the molding die (mold), so as to form the minute projections and recesses on/in the surface of the lip; therefore, the cost of production of the molding die is increased, and the manufacturing cost of the seal member is increased accordingly.
It is an object of the invention to provide a method of producing a seal member, by which a seal member that is able to reduce sliding resistance while assuring sealing performance is easily produced.
A method of producing a seal member according to an aspect of the invention includes: mixing an elastic material and fine particles using a kneading device, so as to form a mixed material; charging the mixed material into a molding die, and forming an elastic molded piece having a shape corresponding to that of a molded seal of the seal member; and removing the fine particles present on a surface of the elastic molded piece, so as to form the molded seal.
The foregoing and further features and advantages of the invention will become apparent from the following description of example embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements and wherein:
First, a rolling bearing device for a wheel on which a seal member produced by a method of producing a seal member according to an embodiment of the invention is mounted will be described.
As shown in
As shown in
The core metal 31 includes a cylindrical portion 32, an annular portion 33, a tapered portion 34, and a radially inner end portion 35. The cylindrical portion 32 is press-fitted in and fixed to an inner periphery of one end portion of the outer ring member 10. The annular portion 33 is formed through a bending process so as to extend radially inward from one end of the cylindrical portion 32. The tapered portion 34 is formed through a bending process so as to extend obliquely and inward from a radially inner end of the annular portion 33. The radially inner end portion 35 is formed through a bending process so as to extend radially inward from a distal end of the tapered portion 34.
The molded seal 40 is bonded to one side face of the core metal 31, i.e., the outer surfaces of the annular portion 33, tapered portion 34, and radially inner end portion 35, so as to form an integral structure.
The molded seal 40 includes a lip 41 that is in sliding contact with the vicinity of a base end portion of the flange 3 of the inner ring member 1, and lips 42, 43 that are in sliding contact with an outer periphery of an inner-ring shoulder portion.
The molded seal 40 is produced by a production method as described below, and its surface including the lips 41, 42, 43 is formed with minute projections and recesses 45.
Next, the method of producing the seal member according to one embodiment of the invention will be described with reference to
The method of producing the seal member according to this embodiment includes a mixing step, a molding step, a particle removing step, and a joining step. First, in the mixing step, as shown in
Then, the elastic material 60 and the fine particles 61 are mixed together by the roller-type kneading device 71, so as to form a mixed material 62.
In this embodiment, water-soluble particles (e.g., salt, sugar, etc.) are used as the fine particles 61.
As the kneading device, a screw-type kneading device may be used in place of the roller-type kneading device 71.
Subsequently, in the molding step, the mixed material 62 is charged into a cavity formed between two molding dies 76, 77 that are placed in the open or closed position, as shown in
Then, the two molding dies 76, 77 are brought into the open position, and the elastic molded piece 65 is removed from the dies 76, 77. When an undercut portion is present in the elastic molded piece 65, the elastic molded piece 65 is removed while the undercut portion of the molded piece 65 is elastically deformed.
Subsequently, in the particle removing step, the fine particles 61 present on a surface of the elastic molded piece 65 are removed, so that the molded seal 40 is formed.
In this embodiment, the fine particles 61 are water-soluble particles; therefore, as shown in
In this manner, the fine particles 61 present on the surface of the elastic molded piece 65 are dissolved and removed, so that the molded seal 40 having minute projections and recesses 45 on its surface is formed.
Finally, in the joining step, the molded seal 40 is bonded integrally to one side face of the core metal 31, i.e., the outer surfaces of the annular portion 33, tapered portion 34 and radially inner end portion 35, with an adhesive or through cure adhesion, for example, to thus form the seal member 30, as shown in
The method of producing the seal member according to this embodiment includes the above-described steps.
Thus, after the mixed material 62 of the elastic material 60 and the fine particles 61 are charged into the molding dies 76, 77, and the elastic molded piece 65 of which the shape corresponds to that of the molded seal 40 is formed, the fine particles 61 present on the surface of the elastic molded piece 65 are removed. In this manner, the molded seal 40 having minute projections and recesses 45 on its surface is easily produced.
Then, the molded seal 40 is joined (bonded) integrally to the core metal 31, so as to provide the seal member 30.
In the seal member 30 produced as described above, the lips 41, 42, 43 of the molded seal 40 assure sealing performance, and the minute projections and recesses 45 formed on the sliding surfaces of the lips 41, 42, 43 serve to reduce the sliding resistance.
Also, in this embodiment, the use of the water-soluble particles as the fine particles 61 makes it possible to dissolve the fine particles 61 present on the surface of the elastic molded piece 65 in the wash liquid (such as hot water, warm water, or ambient temperature water), and easily remove the fine particles 61. Consequently, the molded seal 40 is produced with improved efficiency, at reduced cost.
It is to be understood that this invention is not limited to the illustrated embodiment, but may be embodied in various forms, without departing from the principle of the invention.
For example, this invention may also be implemented in the case where a seal member 130 includes a core metal 131 and a molded seal 140, as shown in
For example, a sealing device having the seal member 130 and the slinger 150 is disposed between a raceway shoulder portion of an inner ring body 5 mounted on an end portion of the hub spindle 4 of the inner ring member 1 of the rolling bearing device for a wheel, and an inner periphery of an end portion of the outer ring member 10, as shown in
While the seal member 30 (130) includes the core metal 31 (131) and the molded seal 40 (140) in the illustrated embodiment, the seal member may consist solely of a molded seal.
According to the present invention, the use of the water-soluble particles makes it possible to dissolve the fine particles present on the surface of the elastic molded piece in the wash liquid (such as hot water or warm water), and easily remove the fine particles, thus effectively improving the productivity and reducing the cost.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-085182 | Apr 2011 | JP | national |
