PURPOSE: To prevent a cut-out to insert a key from breakage, by consisting of a control piston with a piston main body made of synthetic resin and an outer ring made of metal fitted with the circumference of the piston main body, and by piercing the key restricting the movement of a plunger into the above-metnioned piston main body and the outer ring.
CONSTITUTION: The control piston 9 is consisted of the piston 18 as the main body made of synthetic resin and the outer ring 17 made a metal fitted with the circumference of the piston main body. The cut-out wider than an air passage 28 is formed through the piston 18 and the outer ring 17, in the direction of a right angle to the axis of the piston and the ring, connected with the passage 28. The U-shaped key 13, of which limits of forwards and backward movements are restricted by utilizing the cut-out formed in valve plunger 22, is inserte into the above-mentioned cut-out. The key 13 is served to fix a stopper plate 11 which restricts the backward limit of movement of the control piston 9 as well as to fix the above-mentioned piston 18 and the outer ring 17, and is prevented from coming off by a ring spring 12 held by the stopper plate 11.
FUJII TAKASHI
OGURA OSAMU
AISIN SEIKI