Hydraulic brake for transmission

摘要

In a hydraulic brake for a transmission, an assist piston, a reaction piston and a main piston are accommodated on a cylinder. The assist piston has a first acting portion in abutment against the main piston, and the main piston has a second acting portion facing one end of stacked frictional engaging elements. The assist piston and the main piston are moved rightwardly by a hydraulic pressure supplied to a first oil chamber and a second oil chamber to bring the frictional engaging elements into engagement with one another. The first and second acting portions are superposed as viewed axially, thereby preventing a jarring of the assist piston and the main piston. In one embodiment, each of the pistons is formed from a pressed article, whereby the machining cost can be reduced and, moreover, oil passages connecting the first and second oil chambers can be provided in a simple manner.