Vibration isolator
View Patent ↗A vibration isolator having an inner passage of a communication tube that communicates the negative pressure chamber with the valve chamber. A pipe connection part and a supply/discharge pipe communicate the valve chamber with the supply/discharge port of a switching valve on the outside of the vibration isolator. The switching valve selectively communicates the supply/discharge port to either an intake manifold as the negative pressure supply source, or an atmosphere space. The negative pressure chamber communicates with the valve chamber through the communication tube on the inner peripheral side of the outer cylinder member. Thus, either of a negative pressure and an atmospheric pressure, which is same as a pressure in the valve chamber, can be supplied into the negative pressure chamber, by supplying either of the negative pressure and the atmospheric pressure into the valve chamber through the supply/discharge pipe and the pipe connection part.
1. A vibration isolator, comprising:
an outer cylinder member connected to one of a vibration source and a vibration reception portion;
a mount member arranged on an inner peripheral side of the outer cylinder member and connected to the other of the vibration source and the vibration reception portion;
an elastic body arranged between the outer cylinder member and the mount member;
a main liquid chamber filled with a liquid and having partition walls, a part of which is formed partly by the elastic body so that the main liquid chamber has an inner volume that changes as the elastic body deforms;
an auxiliary liquid chamber filled with a liquid and having partition walls, a part of which is formed partly by a diaphragm so that the auxiliary liquid chamber is expandable/contractible;
a first restriction passage for communicating the main liquid chamber and the auxiliary liquid chamber with each other;
a second restriction passage for communicating the main liquid chamber and the auxiliary liquid chamber with each other, the second restriction passage being different in flow resistance from the first restriction passage;
a film-like membrane forming another part of the partition walls of the main liquid chamber, and being elastically deformable in an expanding/contracting direction for increasing/decreasing the inner volume of the main liquid chamber;
a negative pressure chamber provided on an outer side of the main liquid chamber through the membrane, for attracting the membrane to an inner wall when supplied with a negative pressure, to thereby restrain the membrane from deformation in the expanding/contracting direction, and releasing the membrane from the inner wall when supplied with an atmospheric pressure;
a valve mechanism including a valve body supported movably between an open position for opening the second restriction passage and a closed position for closing the second restriction passage, and a valve chamber having walls, a part of which is formed by a movable wall that is movable along an opening/closing direction of the valve body, said movable wall causing the valve body to be moved into the open position when the valve chamber is supplied with the negative pressure, and into the closed position when the valve chamber is supplied with the atmospheric pressure;
an internal passage arranged on the inner peripheral side of the outer cylinder member and communicating the negative pressure chamber and the valve chamber with each other; and
an operating pressure supply passage for communicating one of the negative pressure chamber and the valve chamber with an operating pressure supply source for selectively supplying one of the negative pressure and the atmospheric pressure from the outer side of the vibration isolator,
wherein said internal passage extends through said valve body and said movable wall.
2. A vibration isolator according to claim 1 , wherein said valve body is formed into an annular shape and arranged on an outer peripheral side of said internal passage so as to be slidingly movable along said opening/closing direction, further comprising an annular sliding seal means for liquid-tightly sealing a clearance between an inner peripheral portion of said valve body and an outer peripheral surface of the internal passage, said seal means being movable in said opening/closing direction along the outer peripheral surface of the internal passage.
3. A vibration isolator according to claim 1 , wherein said movable wall is formed into an annular shape and arranged on the outer peripheral side of said internal passage so as to be slidingly movable along said opening/closing direction,
said vibration isolator further comprising an annular, inner peripheral seal means fixedly secured, respectively, to an inner peripheral portion of said movable wall and an outer peripheral surface of said internal passage, for liquid-tightly sealing a clearance between the movable wall and the internal passage, said inner peripheral seal means being elastically deformable in said opening/closing direction.
4. A vibration isolator according to claim 3 , further comprising an annular, outer peripheral seal means fixedly secured, respectively, to an outer peripheral portion of said movable wall and an inner peripheral side of said outer cylinder member, for liquid-tightly sealing a clearance between the movable wall and the outer cylinder member, said outer peripheral seal means being elastically deformable in said opening/closing direction.
5. A vibration isolator according to claim 1 , wherein a space is formed between said elastic body on the inner peripheral side of the outer cylinder member and said diaphragm,
said vibration isolator further comprising a partition member dividing said space into said main liquid chamber and said auxiliary liquid chamber, said membrane and said negative pressure chamber being arranged in association with said partition member.
6. A vibration isolator according to claim 1 , wherein said membrane is comprised of a rubber material and has an outer peripheral portion that is adhered to said partition member by vulcanization, over an entire circumference thereof.
7. A vibration isolator according to claim 1 , wherein said valve mechanism comprises a spring member for urging said valve body toward said closed position through said movable wall.
8. A vibration isolator according to claim 7 , wherein said spring member comprises a coil spring that is arranged in said valve chamber in its compressed state.