Manufacturing method of rocker arm
AssigneeKoyo Seiko Co., Ltd.
InventorNobutsuna Motohashi
Life of this patent
Estimating the term…
Abstract
When forces given in the processes of machining in the cross direction and machining for forming a groove are adjusted and the machining is repeatedly conducted by a plurality of times, the valve engaging portion (10) is machined, and the metal flow (30) formed between the valve guide walls (28, 29) and the connecting wall (8) is prevented from being cut off. Therefore, the rigidity of the valve engaging portion (10) can be ensured, and the quality of the rocker arm (1) can be stabilized.
Claims2
A method of manufacturing a rocker arm for opening and closing a valve, the method comprising the steps of:
- (a) providing a metallic sheet;
- (b) bending the metallic sheet to form a pair of predetermined side wall regions and an predetermined connecting wall region for connecting the pair of predetermined side wall regions;
- (c) first pressing outer sides of the pair of predetermined side wall regions in a connecting direction in which the predetermined connecting wall region extends, respectively, to plastically flow so that a height of the pair of predetermined side wall regions is gradually increased;
- (d) second pressing the predetermined connecting wall region so as to be recessed in a height direction perpendicular to the connecting direction;
- and
- repeating step (c) and (d) plural times, whereby a portions of the pair of predetermined side wall regions are made to be a pair of valve guide walls of a valve engaging portion which extends in the height direction, in which the predetermined connecting wall region is made to be a connecting wall of the valve engaging portion, which connects the pair of valve guide walls with each other at intermediate portion of the pair of valve guide walls in the height direction.
A rocker arm for opening and closing a valve comprising:
- a body including a valve engaging portion with which the valve is engaged, the valve engaging portion including a pair of valve guide walls opposed to each other and a connecting wall for connecting the valve guide walls with each other at a middle position in the height direction of the valve guide walls,
- wherein the body is made of one metallic sheet by plastic deformation so that a metal flow continues between both the valve guide walls and the connecting wall.
Dependencies are inferred from the claim text.