Piston for vehicle disc brake and manufacturing method thereof

Patent metadata

Field	Value
Publication number	US-10465759-B2
Application number	US-201615547445-A
Country	US
Kind code	B2
Filing date	Feb 18, 2016
Priority date	Feb 19, 2015
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

A piston has a piston main body including an aluminum alloy, and a covering layer formed on the outer surface of the piston main body, and the covering layer has a first plating layer including an iron-phosphorous alloy, and a second plating layer including a nickel-phosphorous alloy formed on the first plating layer.

First claim

The invention claimed is:

1. A piston for a vehicle disc brake, the piston being accommodated via a piston seal in a cylinder hole formed in a caliper body of the vehicle disc brake so as to be movable in a disc shaft direction, the piston comprising:
a piston main body made of aluminum alloy; and
a covering layer formed on an outer surface of the piston main body, wherein
the covering layer includes a first plating layer made of iron-phosphorous alloy and a second plating layer made of nickel-phosphorous alloy,
the outer surface of the piston main body having undergone a zincate treatment before the formation of first plating layer of the covering layer thereon, and
the second plating layer being formed on the first plating layer.

2. The piston for a vehicle disc brake according to claim 1 ,
wherein the second plating layer further includes 10 to 30 volume percent of resin particles and the resin particles are made of polytetrafluoroethylene (PTFE).

3. The piston for a vehicle disc brake according to claim 1 ,
wherein the first plating layer has a film thickness of 1 to 15 μm and the second plating layer has a film thickness of 1 to 15 μm.

4. A method for manufacturing a piston for a vehicle disc brake, the piston being accommodated via a piston seal in a cylinder hole formed in a caliper body of the vehicle disc brake so as to be movable in a disc shaft direction, the method comprising the steps of:
forming a first plating layer made of iron-phosphorous alloy on an outer surface of a piston main body made of aluminum alloy using electrolytic plating, the outer surface having undergone zincate treatment; and
forming a second plating layer made of nickel-phosphorous alloy on a surface of the first plating layer using electroless plating.

5. The method for manufacturing a piston for a vehicle disc brake according to claim 4 ,
wherein a plating solution including an iron compound, a phosphinic acid compound, and organic acid is used in the process of forming the first plating layer.

6. The method for manufacturing a piston for a vehicle disc brake according to claim 5 ,
wherein the organic acid is glycine and L-ascorbic acid.

7. The method for manufacturing a piston for a vehicle disc brake according to claim 4 ,
wherein the second plating layer further includes 10 to 30 volume percent of resin particles and the resin particles are made of polytetrafluoroethylene (PTFE).

8. The piston for a vehicle disc brake according to claim 2 ,
wherein the first plating layer has a film thickness of 1 to 15 μm and the second plating layer has a film thickness of 1 to 15 μm.

9. The method for manufacturing a piston for a vehicle disc brake according to claim 5 ,
wherein the second plating layer further includes 10 to 30 volume percent of resin particles and the resin particles are made of polytetrafluoroethylene (PTFE).

10. The method for manufacturing a piston for a vehicle disc brake according to claim 6 ,
wherein the second plating layer further includes 10 to 30 volume percent of resin particles and the resin particles are made of polytetrafluoroethylene (PTFE).

Assignees

• Nissin Kogyo Kk
• Univ Shinshu

Inventors

• Okamoto Minoru
• Takahashi Yohei
• Arai Susumu
• Ueda Miyoka

Classifications

• C25D5/44

  Aluminium · CPC title

• C25D3/562 Primary

  containing more than 50% by weight of iron or nickel or cobalt · CPC title

• C23C18/32

  Coating with nickel, cobalt or mixtures thereof with phosphorus or boron (C23C18/50 takes precedence) · CPC title

• C23C18/1662

  Use of incorporated material in the solution or dispersion, e.g. particles, whiskers, wires · CPC title

• C23C18/1653

  Two or more layers with at least one layer obtained by electroless plating and one layer obtained by electroplating · CPC title