| 摘要 |
PROBLEM TO BE SOLVED: To provide a master cylinder capable of suppressing invalid stepping force.SOLUTION: A piston seal 45 has a toric base part 101 in which are protrudingly provided an inner peripheral lip part 102 that slidably contacts an outer peripheral face 18A of a piston 18 and an outer peripheral lip part 103 that contacts a circumferential groove 32 of a cylinder main body 15. In the base part 101 are formed in a circumference direction a plurality of protrusions 112 that protrude in an opposite direction of the inner peripheral lip part 102 and the outer peripheral lip part 103. In a circumferential wall 89 near an opening part of the cylinder main body 15 of the circumferential groove 32 is formed an inclined face part 89b so as to get narrower from a bottom part toward the opening part of the cylinder main body 15, and the inclined face part 89b is formed at a position to which the plurality of protrusions 112 contact.SELECTED DRAWING: Figure 2 |
