# US 4,395,442 A · Method of coating the working surfaces of piston operating devices

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- Number: US 4,395,442 A
- Document ID: US4395442A
- Status: Granted
- Kind: A
- Application number: 06/327,338
- Filed: 1981-12-04
- Granted: 1983-07-26
- Earliest claimed: 1980-12-19
- Assignees: WABCO Fahrzeugbremsen GmbH
- Inventors: Gunther Meise; Herbert Unger
- Web page: https://patentgrep.com/patent/US4395442A

## CPC

- F04B 39/126: {Cylinder liners}
- F02B 77/02: Surface coverings of combustion-gas-swept parts (of pistons F02F3/10; of cylinders and cylinder heads F02F1/00)
- F02B 1/04: with fuel-air mixture admission into cylinder
- Y10T 29/49263: by coating or cladding
- Y10T 29/49272: with liner, coating, or sleeve
- F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F)
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A method of protecting the frictional engaging surfaces of an aluminum alloy piston-cylinder machine, including the steps of: coating the surface of one of the piston-cylinder members with an epoxy-resin in which is mixed a ceramic oxide material, placing the coated member in a drier oven, and heating and curing the epoxy-resin and ceramic oxide coating for at least one hour at a temperature of approximately 220.degree. C.

## Claims

### Claim 1

A process of protecting the mating surfaces of a piston type of machine including the steps of: coating at least one of the mating surfaces of the piston-cylinder members by spraying under pressure a varnish having an epoxy-resin base in which is mixed a ceramic oxide material which contains sintered aluminum oxide and zirconium oxide, placing the varnish coated member in an oven, and heating the varnish coated member at a given temperature for a given period of time to result in a hardened wear-resistant surface finish.

### Claim 2 (depends on 1)

The process as defined in claim 1, wherein the thickness of said varnish coat is between 20 and 40 .mu.m.

### Claim 3 (depends on 2)

The process as defined in claim 2, wherein the thickness of said varnish coat is 30 .mu.m.

### Claim 4 (depends on 1)

The process as defined in claim 1, wherein the given temperature of the oven is more than 200.degree. C.

### Claim 5 (depends on 4)

The process as defined in claim 4, wherein the given period of time is approximately one hour and the given temperature is approximately 220.degree. C.