Plastic and nonmetallic article shaping or treating: processes – With printing or coating of workpiece – Anti-stick or adhesion preventing coating
Reexamination Certificate
2002-03-05
2004-10-05
Tentoni, Leo B. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
With printing or coating of workpiece
Anti-stick or adhesion preventing coating
C264S159000, C264S269000, C264S297100, C264S300000, C427S230000, C427S236000
Reexamination Certificate
active
06800230
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a disc brake piston seal member, attached to a ring-shaped groove formed on an inner circumferential surface of a cylinder hole of a brake caliper, in a slidable and close contact with an outer circumferential surface of a piston slidably engaged with the cylinder hole, and a method for manufacturing the seal member.
2. Description of Background Art
In a disc brake, if hardness and fastening allowance of a piston seal member change in accordance with temperature change, a friction coefficient of the piston seal member to the piston changes, consequently, a seal characteristic, brake-gap adjustment characteristic and the like of the piston seal member may be degraded.
Accordingly, to always stabilize the friction coefficient between the piston and the piston seal member regardless of temperature change, it is conventional to form a plate layer with a low friction coefficient on the outer circumferential surface of the piston (See, e.g., JP-A No. H11-63047).
However, to form a plate layer with a low friction coefficient on the outer circumferential surface of the piston as described above, a comparatively-troublesome plating processing is required. Further, as the plating processing must be performed on the entire outer circumferential surface of the piston, the costs of the disc brake increases.
The present invention has been made in view of the above situation, and has its object to provide a disc brake piston seal member and its manufacturing method capable of stabilizing the friction coefficient to the piston without an increase in cost.
SUMMARY AND OBJECTS OF THE INVENTION
To attain the above object, the present invention provides as its first aspect a disc brake piston seal member, attached to a ring-shaped groove formed on an inner circumferential surface of a cylinder hole of a brake caliper, in a slidable and close contact with an outer circumferential surface of a piston slidably engaged with said cylinder hole, wherein at least the inner circumferential surface, in close contact with the outer circumferential surface of said piston, is coated with a friction reducing agent.
Note that the piston seal member corresponds to a dust seal member
12
and a brake-gap adjustment seal member
13
in an embodiment of the present invention to be described later, and the ring-shaped groove corresponds to first and second ring grooves
10
and
11
in the embodiment of the present invention to be described later.
According to the first aspect, even if the hardness and fastening allowance of the piston seal member change due to temperature change, the friction coefficient of the seal member to the piston can be stabilized. Accordingly, if this piston seal member is a dust seal member, its seal function can always be normally performed, and the sliding resistance of the piston can be reduced Further, if the piston seal member is a brake-gap adjustment seal member, the roll back amount of the seal member upon withdrawal of the piston can always be constant, thus the brake-gap adjustment function can be stabilized.
Further, the coating of the friction reducing agent can be performed only in an extremely small region, i.e., the inner circumferential surface of the piston seal member, and can be easily performed by brush-coating, spray coating or the like, the increase in the costs of the disc brake by this coating is extremely small.
Further, the present invention provides, as a second aspect, upon the manufacture of the disc brake piston seal member, a coating of an inner circumferential surface of a cylindrical seal material with the friction reducing agent; and cutting said seal material into ring pieces, thus manufacturing multiple piston seal members.
According to the second aspect, multiple piston seal members coated with the friction reducing agent on their inner circumferential surfaces can be efficiently manufactured. Especially, as the coating of the friction reducing agent can be performed only once per one seal material, the increase in the costs of the disc brake by the coating is further extremely small.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
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Ishikawa Yoshimi
Kuwahara Shinichi
Noro Hirofumi
Birch & Stewart Kolasch & Birch, LLP
Honda Giken Kogyo Kabushiki Kaisha
Tentoni Leo B.
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