# US 5,349,748 A · Method of manufacturing a tappet for an internal combustion engine

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- Number: US 5,349,748 A
- Document ID: US5349748A
- Status: Granted
- Kind: A
- Application number: 08/103,223
- Filed: 1993-08-09
- Granted: 1994-09-27
- Earliest claimed: 1993-03-26
- Assignees: Fuji Oozx Inc.
- Inventors: Nobuo Hara
- Web page: https://patentgrep.com/patent/US5349748A

## CPC

- F01L 1/143: {for use with overhead camshafts}
- F01L 2303/00: Manufacturing of components used in valve arrangements
- F02B 2275/18: DOHC [Double overhead camshaft]
- Y10T 29/49247: Valve lifter making
- Y10T 29/49304: Valve tappet making
- Y10T 29/49314: with assembly or composite article making
- F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- 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 manufacturing a tappet used in a valve operating mechanism of a direct acting type in an internal combustion engine. A tip engaged with a center bore of an inner upper surface of a tappet body includes upper and lower convex surfaces and a rounded upper circumferential corner having a certain curvature. thereby preventing concentration of stress even if the tip is subject to high compression load. Thus, durability and reliablity of the tappet are increased.

## Claims

### Claim 1

A method of manufacturing a tappet for use in an internal combustion engine comprising the steps of:
providing a plastically deformable, cup-shaped cylindrical tappet body closed at an upper end and having an inner upper surface;
forming an engage bore having a flat upper surface at the center of the inner upper surface of the cylindrical tappet body;
inserting a tip having upper and lower convex surfaces and a rounded upper circumferential corner having a certain curvature within the engage bore; and
imposing force upon the lower convex surface of the tip plastically deforming the inner upper surface of the engage bore forming a concave surface in the inner upper surface of the engage bore corresponding to the upper convex surface of the tip.

### Claim 2 (depends on 1)

A method for manufacturing a tappet as defined in claim 1 including the step of deforming inwardly the inner upward surface of said cylindrical tappet body adjacent the engage bore fixing said tip within the engage bore.

### Claim 3

A method of manufacturing a tappet comprising the steps of:
forming an engage bore having a flat upper surface at a center of an inner upper surface of a plastically deformable cylindrical tappet body which is closed at an upper end;
inserting a tip having upper and lower convex surfaces and a rounded upper circumferential corner having a certain curvature into the engage bore;
pressing the tip strongly until the inner upper surface of the engage bore is plastically deformed to form a concave surface corresponding to the upper surface of the tip and to caulk a downward circumferential projection around the engage bore inwardly.