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Publication numberUS3545415 A
Publication typeGrant
Publication dateDec 8, 1970
Filing dateApr 8, 1968
Priority dateApr 8, 1967
Publication numberUS 3545415 A, US 3545415A, US-A-3545415, US3545415 A, US3545415A
InventorsMori Yoshio
Original AssigneeNippon Piston Ring Co Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Valve lifter with thin plastic coating
US 3545415 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent Yoahio Mori inventor Tokyo, Japan Appl. No. 719,371 Filed April 8, 1968 Patented Dee. 8, 1970 Assignee Nippon Piston Ring Co., Ltd.

Tokyo, Japan Priority April 8, 1967 Japan VALVE LIFTER WITH THIN PLASTIC COATING 2 Claims, 1 Drawing Fig.

US. Cl.

Int. Cl. .4 F24c 3/00 Field 01' Search 74/569;

Primary Examiner-Benjamin W. Wyche, III AltomeySughrue, Rothwell, Mion, Zinn & MacPeak ABSTRACT: A valve lifter having mutually sliding surfaces requiring little or no lubrication, wherein at least one of said surfaces is coated with polytetrafluoroethylene.

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1 VALVE LIFTER WITH THIN PLASTIC COATING BACKGROUND OF THE INVENTION This invention relates to construction of an improved valve lifter, particularly to a valve lifter for easy use in combustion engines.

Lubricating oil is normally supplied on theface where the valve lifter makes contact with the cam face and on the sliding surfaces where the valve lifter slides against a guide. It is usually necessary to wet the sliding parts of the valve lifter with a lubricating oil spread over the contactsurfaces of metal at the start of the engine operation. Until the surfaces are adequately lubricated, scuffing, friction loss will occur. Engine performance is therefore substantially reduced at the start of its operation and considerable scuffing and abrasion by its sticking may result during these relatively brief periods. The

problem has now become magnified with the advent of hard. alloy-metal valve lifters for high speed rotation, since the harder the material is, the more abrasion and scuffing will occur at the beginning of the engines operation.

BRIEF DESCRIPTION OF THE DRAWING The FIG. is a sectional side elevationof a valve lifter wherein the sliding surfaces are coated with polytetrafiuoroethylene.

SUMMARY OF THE INVENTION DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawing illustrating the invention is a sectional side elevation of the valve lifter and the cam, numeral 1 is the valve lifter, numeral 2 is the cam, numeral 3 is the cylinder block. The valve lifter, the cam and the sliding contact surface between the valve lifter and the mating guide portion are coated with polytetrafluoroethylene. The coating may be put on either the valve lifter and the cam or the contact surface of the valve lifter and the mating guide portion, since the polytetrafluoroethylene coated on one surface will partly adhereto the surfaces contacted therewith forming a film of the resin on the latter during the sliding contact. In the embodiment shown, the resin is coated onto the surface 4 and 5, whereby these surfaces contact with surfaces 4' and 5' respectively and a film of the resin is formed on the surfaces 4' and The thickness of the film of polytetrafluoroethylene is not critical but it in general should be between about 5-300 (p. microns). The full effect however, will not be obtained if the thickness is under 5p. Over 300p. the film often is loosened and might be removed by the sliding contact. Preferably, the thickness of the resin for the valve lifter of the combustion engine for automobile,is about 10p.

The coating of polytetrafluoroethylene resin can be achieved by well known methods, i.e., flowing, spraying, enameling etc., but best results are obtainable by spraying. Spraying is accomplished as follows: The valve lifter, cam, and

mating guide portion are demated and their surfaces cleaned with water, liquid honed, and cleaned again with water to make it easier to adhere the resin. These are dried in the air. The aperture of the spray gun is suitably about 0.8-1.0 mm. The coating liquid is made by using water, thinner or other so]- vents. The coating liquid should be, agitated and passed through a filter of 100-200 mesh stainless wire. It is preferable to operate at the condition of 2-3 kg./cm. spray pressure and at 1520 cm. distance from the surface to be coated.

A suitable exhaust system IS arranged in the place where the spraying is done and where it is kept clean without suspended matter such as dust.

After spraying, the member isdried under 90 C. Infrared rays may be used for heating. Rapid drying should be avoided to protect the film from forming wrinkles and cracking.

The member is them put into a furnace and baked at a temperature of 350--400 C., and quenched whereby the film is made tenacious. The film of resin may be provided either on the surface 4 and 5 or on the surface 4' and 5, but it easier in operation to coat it on the surface 4 and 5 than 4' and 5'.

Polytetrafluorethylene applied to the invention has a very small coefficient of friction, and also is so lubricous that it fully functions as a lubricant even if lubricating oil is not supplied. Therefore, it does no happen that scuffing is caused at the contact surface of the valve lifter and the cam at the beginning of the running of the engine; also friction loss between the lifter and the guide is minimized.

In this way, a stable sliding between the surfaces is made possible providing a more fully effective engine even from the start of engine operation,

This invention can be adapted to the construction of any of various shapes and qualities of valve lifter i.e., it is applicable in the construction of valve lifter comprised as follows:

1. In an internal combustion engine having a rotating cam and a driven valve lifter having surfaces adapted for sliding contact with said rotating cam and with the block of said internal combustion engine, the improvement comprising a coating on at least one of said surfaces composed of a film of polytetrafiuoroethylene having a thickness of from 5 to 300p..

2. The improved valve lifter as in claim 1, wherein the thickness of said film is about 10 microns.

in air or heated in air.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4380216 *Sep 17, 1980Apr 19, 1983Tecumseh Products CompanyEconomical engine construction
US4686867 *Jun 16, 1986Aug 18, 1987Ste LookBicycle pedal and shoe fastening combination
US4745817 *Jun 14, 1985May 24, 1988Honda Giken Kogyo Kabushiki KaishaPiston/crank connection mechanism for an internal combustion engine
US4790049 *Apr 20, 1987Dec 13, 1988Grosh Jack FRope locking device
US4800856 *Mar 11, 1985Jan 31, 1989Outboard Marine CorporationAbrasion resistant roller apparatus for internal combustion engines
US4841800 *Mar 9, 1987Jun 27, 1989Ampex CorporationAdjustable control lever
US4876996 *Mar 7, 1989Oct 31, 1989Ina Walzlager Schaeffler KgDevice for the valve control gear of an internal combustion engine
US4909198 *Feb 28, 1989Mar 20, 1990Toyota Jidosha Kabushiki KaishaAluminum alloy valve lifter with sprayed coating and method of producing same
US5185923 *Aug 9, 1991Feb 16, 1993Ngk Spark Plug Co., Ltd.Method of making a frictionally sliding component
US5228418 *Apr 14, 1992Jul 20, 1993Firma Carl FreudenbergTappet for a valve in an internal combustion engine
US5237967 *Jan 8, 1993Aug 24, 1993Ford Motor CompanyPowertrain component with amorphous hydrogenated carbon film
US5249554 *Jan 8, 1993Oct 5, 1993Ford Motor CompanyPowertrain component with adherent film having a graded composition
US5320074 *Jun 17, 1993Jun 14, 1994Sealed Power Technologies Limited PartnershipDirect acting hydraulic tappet
US5743224 *Jul 8, 1996Apr 28, 1998Unisia Jecs CorporationValve lifter surface and processing method thereof
US5816207 *Jan 16, 1997Oct 6, 1998Nsk Ltd.Tappet roller bearing
WO1980002054A1 *Mar 19, 1979Oct 2, 1980Goloff ACam roller follower
WO1988007232A1 *Mar 8, 1988Sep 22, 1988AmpexAdjustable control lever
U.S. Classification123/90.51, 74/569
International ClassificationF01L1/14
Cooperative ClassificationF01L1/14
European ClassificationF01L1/14