| 摘要 |
<p>A brake system that includes a friction plate composed of inner friction plates and outer friction plates that are arranged alternately in an axial direction; a cylinder portion that is open toward the friction plate in the axial direction; a piston member that slidably fits into an opening portion of the cylinder portion, thereby forming a working oil chamber, and that is pressed and driven away from the cylinder portion in the axial direction by oil pressure supplied to the working oil chamber, thereby pressing the friction plate; a return spring that biases the piston member toward the cylinder portion in the axial direction; and a drum member integrally provided with a drum portion that is in spline engagement with the friction plate, a pressure-receiving portion that is formed in a vertical direction to the axial direction and receives a reaction force of the return spring, and a fixed portion.</p> |
