| 摘要 |
<p>PURPOSE:To prevent the reduction in roughness of the cylinder hole inside surface due to electrochemical corrosion by forming an annular expanded portion having a sliding surface at its outer periphery of a synthetic resin so as to establish a sliding engagement between a metal and a synthetic resin. CONSTITUTION:The piston 3 of the cylinder main body 1 of a single master cylinder comprises a portion 4 made of a synthetic resin and a central reinforcement member 5 made of a metal. The portion 4 is provided with annular expanded portions 6 and 7 for sliding engagement, and seal cups 8 and 9 are fitted liquidtight in front of the portions 6 and 7 respectively. The reinforcement member 5 is provided at its front end with a flange 12 for reinforcing the expanded portion 7. This constitution prevents abnormal forces from acting on the portion 4 and protects the cylinder inside surface from scratch and wear on the movement of the piston 3. The member 5 does ot require finishing because it does not slide, and the portion 4 does not require machining because it can be molded.</p> |
