| 摘要 |
<p>PURPOSE:To make smooth sliding motion securable, by constituting a master cylinder piston with a first piston and a second piston being opposed with each other with an annular groove between, while making a support surface of the piston wider to a cylinder hole. CONSTITUTION:A front piston 11 of a master cylinder piston is divided into a first piston 13 in front and a second piston in the rear, and these pistons 13 and 14 are opposed with each other with an annular groove 15 between. A chamfered part 16, where an inner circumferential surface is partially shaved off, is formed on an outer circumference of the first piston. In addition, on the outer circumferential part of the second piston 14, there are taper parts 17 at both sides in front and in the rear, and width (a) of the outermost circumferential surface is made to be smaller than a diameter of a supply port 8 in design. Therefore, a piston 4 is supported on a wide support surface by these first and second pistons 13 and 14 so that stable sliding motion is performable.</p> |
