Honda Giken Kogyo Kabushiki Kaisha

Kiminobu Terao

Yorinori Kumagai

Takamichi Shimada

Junya Nagai

Kouji Ueda

Kenji Amano

Toshio Oka

Mayumi Takada

Yoichi Kojima

Yoshihiro Kodama

A hydraulic seal system includes a seal ring groove and a seal ring mounted in the seal ring groove. The seal ring and seal ring groove are rotatable relative to each other, and have sealing sides, respectively, which are put into pressure contact with each other by a sealing hydraulic pressure. The seal ring is made of a synthetic resin to have a fixed elasticity. The sealing side of the seal ring is formed into a convex curved surface with its radially central portion raised, so that when a hydraulic pressure is applied, the sealing side can be compressedly deformed to define a hydraulic pocket. Thus, the formation and retaining of an oil film at the pressure contact portions of the sealing sides is promoted.

Hydraulic seal system

One end of a seal ring retained in a seal ring groove is formed in such a manner that it is offset radially inwardly from the other end, so that oil is permitted to leak by opening an abutment joint formed by the two ends in a condition in which no hydraulic pressure is applied. If a hydraulic pressure is supplied to bring a hydraulic actuator into an engaged state, the one end of the seal ring is deformed radially outwardly by the hydraulic pressure to come into close contact with a sealing surface and to close the abutment joint, thereby preventing the oil from-leaking past the oil ring. Consequently, upon engagement of the hydraulic actuator, a sealing property or salability of the oil can be assured, and upon releasing of the engagement of the hydraulic actuator, an oil leaking property of the seal ring can be provided, leaking property of the oil can be provided, thereby enhancing the responsiveness of the hydraulic actuator.

Hydraulic sealing device

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.

Hydraulic brake for transmission

In a sealing device, a crank-shaped oil channel is defined in an abutment of a sealing ring for sealing between a shaft member and a housing which surrounds the shaft member and is rotatable relative the shaft member. The crank-shaped oil channel is comprised of a first oil channel portion and a second oil channel portion which extend axially, and a third oil channel portion which connects the first and second oil channel portions to each other. If the sealing ring is thermally expanded circumferentially due to a change in temperature, the sectional area of the flow path in each of the first and second oil channel portions is varied, but the sectional area of the flow path in the third oil channel portion is not substantially varied. Therefore, it is possible to leak a given amount of an oil from one side of the sealing ring through the crank-shaped oil channel to the other side, thereby preventing the wearing of the shaft member caused by foreign matter, such as an iron powder, contained in the oil.

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Saitama, Japan

Kiminobu Terao