A variable stiffness vibration damping device includes a first support member, a second support member, a pair of main elastic members, a partition elastic member, a first communication passage, a pair of first radial walls, a second communication passage, a coil, a yoke, and a magnetic fluid. The second support member includes an axial portion. The first communication passage is provided in one of the first support member and the axial portion such that a first liquid chamber and a second liquid chamber communicate via the first communication passage. The pair of first radial walls partition one of the first liquid chamber and the second liquid chamber into a pair of third liquid chambers. The second communication passage is provided in the one of the first support member and the axial portion such that the pair of third liquid chambers communicate via the second communication passage.

In a fluid-filled vibration damping device in which multiple fluid chambers filled with a magnetic functional fluid communicate with each other by an orifice path, and a magnetic unit applying a magnetic field to the orifice path is provided in a state of being externally inserted to an outer cylindrical member, the magnetic unit includes a magnetic field generation part forming a magnetic field and a magnetic path formation part inducing a magnetic flux, the magnetic field is applied from a magnetic gap part of the magnetic path formation part arranged on an outer circumference of the orifice path to the orifice path, and on an outer circumferential surface of the outer cylindrical member, an installation part to which an outer mounting member realizing linking between the outer cylindrical member and a vibration damping linking target member is installed is biased from the magnetic field generation part in an axial direction.

A liquid filled bushing assembly includes an inner tubular member (11), an outer tubular member (12) disposed in a coaxial relation to the inner tubular member, and an elastic member (13) interposed between the inner tubular member and the outer tubular member, wherein not only the stiffness of the liquid filled bushing assembly in the lateral directions can be freely selected but also the stiffness of the liquid filled bushing assembly in the rotational direction and/or the axial direction can be freely selected.

A mount bush includes: an inner tubular member; an outer tubular member arranged coaxially with the inner tubular member and surrounding an outer periphery of the inner tubular member with a clearance; and an elastic member connecting the inner tubular member with the outer tubular member, wherein the inner tubular member includes: an inner yoke having a coil therein; and an outer yoke coaxially coupled with the inner yoke at a radially outer position than the coil, and the elastic member has a first and second fluid chambers, facing each other across an axis of the inner tubular member and having magnetic fluid encapsulated therein, whose viscosity varies by a magnetic field, wherein the outer yoke has a communication passage communicating the first fluid chamber with the second fluid chamber, and is provided with a permanent magnet to generate a magnetic field in the communication passage.

A mount bush includes a tube member, a shaft member disposed coaxially with an axis of the tube member and having a coil, a first liquid chamber disposed at an upper side in an internal space between the tube member and the shaft member, a second liquid chamber in communication with a lower side of the first liquid chamber and containing a magnetic viscoelastic fluid, and a third liquid chamber in communication with a lower side of the second liquid chamber and having a porous body, wherein the coil is disposed such that a magnetic path that passes through the second liquid chamber in an orientation along at least one of an axial direction and a radial direction is formed through electrical conduction.

A hydraulic mount apparatus includes a housing having an upper and a lower portion disposed on a center axis and defining a housing chamber. A partition member is disposed in the housing chamber dividing the housing chamber into a pumping chamber and a receiving chamber. The pumping chamber extends between the upper portion and the partition member. The receiving chamber extends between the lower portion and the partition member. A decoupler attaches to the partition member separating the pumping and the receiving chambers. A moving member of elastomeric material, disposed in the pumping chamber, attaches to the decoupler. The moving member is molded from a first elastomeric material having a first hardness level and a second elastomeric material having a second hardness level with the first hardness level and the second hardness level being different from one another. The second hardness level is less than the first hardness level.

A system and method using a mount assembly for attaching a powertrain to a structural member of a vehicle. The mount assembly includes a first compliant member, a second compliant member, a first fluid chamber, a second fluid chamber, a pressure compliant membrane, electro-magnetorheological switch and a magnetorheological fluid. A fluid conduit interconnects the first fluid chamber with the second fluid chamber to allow a fluid to pass from the first fluid chamber to the second fluid chamber. The pressure compliant membrane seals the aperture in the second fluid chamber. The electro-magnetorheological switch is activated to generate an electric field in the fluid conduit to change the viscosity of the magnetorheological fluid to achieve a first stiffness profile of the mount assembly. The electro-magnetorheological switch is deactivated to remove the electric field in the fluid conduit to change the viscosity of the magnetorheological fluid to achieve a second stiffness profile of the mount assembly.

A system comprises an elastic mount configured to support a propulsion device with respect to a marine vessel. The elastic mount contains an electromagnetic fluid. An electromagnet is configured so that increasing an amount of electricity applied to the electromagnet increases the shear strength of the electromagnetic fluid in the elastic mount and thereby decreases elasticity of the elastic mount, and so that decreasing the amount of electricity applied to the electromagnet decreases the shear strength of the electromagnetic fluid in the elastic mount and thereby increases the elasticity of the elastic mount. A controller automatically adapts the amount of electricity applied to the electromagnet based on one or more sensed conditions so as to improve performance and/or handling of the marine vessel.

A hydraulic mount assembly includes a mount body defining a cavity. A powertrain includes a dynamic mass, and a structure that supports the dynamic mass. The assembly is attached to the structure and supports the dynamic mass. A first plate is fixed relative to the mount body inside the cavity to separate the cavity into a first chamber and a second chamber. The first plate defines a plurality of first passages that fluidly connects the first and second chambers. A decoupler is disposed between the first and second chambers. An actuator is coupled to the first plate. The decoupler is movable in response to actuation of the actuator. The decoupler abuts the first plate when in a locked position to prevent fluid communication through the first passages. The decoupler is movable relative to the first plate when in an unlocked position to allow fluid communication through the first passages.

In a vibration damping device applying a magnetic force from a magnetic field generation unit to an orifice path communicating with fluid chambers into which a magnetic functional fluid is filled and controlling vibration damping properties. An intermediate cylindrical member to which an outer cylindrical member formed by a non-magnetic material is externally fit and fixed is formed by a ferromagnetic material. In the intermediate cylindrical member, a magnetic field acting opening part is provided at a position corresponding to the orifice path.