Nissan Motor Company Limited

Bridgestone Corporation

Hajime Takeguchi

Tatsuro Ishiyama

Toshiyuki Tabata

Takao Ushijima

Nobuaki Fujiwara

Toshihiko Aihara

In order to prevent relative displacement between two elements which form part of a separation assembly used to define first and second auxiliary chambers within a fluid filled vibration insulator, the two members are fixedly connected together prior assembly.

Multi-chamber fluid filled vibration insulator

A power unit mount through which a power unit is supported on a vehicle body in a manner to insulate vibration transmission. The power unit mount is comprised of an elastomeric support body fixedly interposed between inner and outer cylindrical members which are connected respectively to the vehicle body and the power unit. The elastomeric support body is formed with a hollow defining a main fluid chamber. An elastomeric diaphragm is provided to define an auxiliary fluid chamber which is communicable with the main fluid chamber through first and second orifice passages which extend along the inner periphery of the outer cylindrical member. Liquid fills the main and auxiliary fluid chambers and the orifice passages. In the first orifice passages, the resonance point of the liquid is tuned to increase the loss factor of the power unit mount in response to relatively low frequency vibration, thereby dampening engine shake. In the second orifice passage, the resonance point of the liquid is tuned to lower the dynamic spring constant of the power unit mount in response to relatively high frequency vibration, thereby dampening idling vibration of the power unit. Additionally, a movable plate arrangement is disposed in the second orifice passage and adapted to close the orifice passage in response to the relatively low frequency vibration, thereby permitting fluid passage through only the first orifice passage during input of the relatively low frequency vibration.

Fluid-filled power unit mount

A bush-type vibration damping device having an inner cylinder and an outer cylinder arranged in such a way that their axes extend in parallel with each other, and an elastic member is interposed between the inner and outer cylinders. A pressure receiving chamber, a first sub-liquid chamber and a second sub-liquid chamber are provided at one side of the inner cylinder. The first sub-liquid chamber has a not smaller resistance to expansion by pressure than the second sub-liquid chamber. The first and second sub-liquid chambers are connected to the pressure receiving liquid chamber through first and second communication passages, respectively. The second communication passage produces a not smaller resistance to flowing liquid than the first communication passage. Vibration of a comparatively low frequency and large amplitude is adsorbed by the flow resistance encountered by a liquid displaced through the second communication passage, while vibration of a comparatively high frequency and small amplitude causes a resonance of the liquid in the first passage so as to limit increase in the dynamic spring constant.

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Yokohama, Japan

Hajime Takeguchi