FLUID-FILLED VIBRATION DAMPING DEVICE AND SEAL STRUCTURE FOR AIR CHAMBER IN THE SAME

Abstract

A construction of a fluid-filled vibration damping device provided with an air chamber for applying an air pressure capable of increasing the pressure of a fluid in a fluid chamber is realized advantageously in industry. An air chamber is formed between a cylindrical member and a bottom member forming a second mounting member, and a seal protrusion that is caused to fall easily to the inside of the air chamber is interposed between these elements. In the state in which the air chamber is formed, the cylindrical member and the bottom member are brought close to each other and lapped on each other, by which the volume of the air chamber is decreased by an amount corresponding to the approach amount of the elements and the volume amount of the seal protrusion entering into the air chamber due to falling, and thereby the internal pressure of the air chamber is increased.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, advantages and technical and industrial significance of the present invention will be better understood by reading the following detailed description of a presently preferred embodiment of the invention, when considered in connection with the accompanying drawings, in which:

FIG. 1 is a longitudinal section explanatory view showing one embodiment of a fluid-filled vibration damping device having a structure in accordance with the present invention;

FIG. 2 is a longitudinal section explanatory view showing a diaphragm mounted in the fluid-filled vibration damping device shown in FIG. 1;

FIG. 3 is a partially enlarged explanatory view of FIG. 2;

FIG. 4 is a view for explaining an example of one step for forming and sealing an air chamber in manufacturing the fluid-filled vibration damping device shown in FIG. 1, showing a state in which a partition member and a diaphragm are assembled to an integral vulcanized molded product formed by connecting a cylindrical member in a second mounting member to a first mounting member by means of an elastic rubber body to form a pressure-receiving chamber and an equilibrium chamber;

FIG. 5 is a view for explaining a step carried out following the step shown in FIG. 4, showing a state in which a bottom member is inserted in a staking portion of a cylindrical member to form an air chamber;

FIG. 6 is a view for explaining a step carried out following the step shown in FIG. 5, showing a state in which the insertion amount of bottom member is increased gradually with respect to a staking portion of a cylindrical member to gradually increase the internal pressure of an air chamber;

FIG. 7 is a view for explaining a step carried out following the step shown in FIG. 6, showing a state in which a bottom member is fixed by staking to a staking portion of a cylindrical member to seal an air chamber in such a manner that the internal pressure of the air chamber is higher than the atmospheric pressure;

FIG. 8 is a view for explaining an example of one step for forming and sealing an air chamber when another embodiment of a fluid-filled vibration damping device having a structure in accordance with the present invention, showing a state in which a bottom member is inserted onto the end portion of a cylindrical member to form the air chamber; and

FIG. 9 is a view for explaining a step carried out following the step shown in FIG. 8, showing a state in which a bottom member is fixed to a cylindrical member to seal an air chamber in such a manner that the internal pressure of the air chamber is higher than the atmospheric pressure.

Claims

1. A fluid-filled vibration damping device comprising: a first and a second mounting members which are spaced apart from each other;an elastic rubber body which elastically connects said first and second mounting members;a partition member supported by said second mounting member and cooperating with said elastic rubber body to define a pressure-receiving chamber which is filled with a non-compressible fluid and in which an internal pressure is changed by receiving an input vibrational load;a flexible diaphragm cooperating with said partition member to define an equilibrium chamber on one of the opposite sides of said partition member remote from said pressure-receiving chamber, said equilibrium chamber being filled with the fluid, and said flexible diaphragm being displaceable to permit a change in volume of said equilibrium chamber;an orifice passage provided to allow said pressure-receiving chamber and said equilibrium chamber to communicate with each other; andan air chamber filled with air with a pressure higher than an atmospheric pressure, and formed on the opposite side to said equilibrium chamber, so as to hold said flexible diaphragm between said air chamber and said equilibrium chamber, and an air pressure in said air chamber being applied to said fluid in the equilibrium chamber, whereby the pressure of said fluid may be increased,wherein said second mounting member comprises:a cylindrical member located at said first mounting member side, and having a cylindrical shape; anda bottom member located at the opposite side to said first mounting member, the bottom member being fixed to said cylindrical member and cooperating with said cylindrical member to support said partition member and said flexible diaphragm and forming said air chamber between said flexible diaphragm and said bottom member in a state of being lapped on an end portion of said cylindrical member so as to cover an opening on the opposite side to said first mounting member in said cylindrical member; andwherein said device further comprises:a seal member formed of an elastic material, the seal member being interposed between the lapped portions of said cylindrical member and said bottom member in a compressedly deformed state to seal the lapped portion in a fluid-tight manner; anda first seal protrusion formed by a part or a whole of said seal member, having a chevron shape, projecting in the direction such that said cylindrical member and said bottom member are lapped on each other, extending continuously in a circumferential direction so as to surround said air chamber, and being configured so that a cross-sectional shape has an inside surface facing to said air chamber and an outside surface opposite to the inside surface, and an internal angle of the inside surface being larger than the internal angle of the outside surface so that said first seal protrusion easily falls to said air chamber side at the time of compressed deformation caused by lapping of said bottom member on said cylindrical member; andwherein said seal member is interposed between said cylindrical member and said bottom member, either one of said cylindrical member and said bottom member is brought into contact with a tip end portion of said first seal protrusion, and from a state in which said air chamber, the air therein being incapable of going in from an outside and going out to the outside, is formed between the bottom member and the flexible diaphragm, the cylindrical member and the bottom member are brought close to each other and lapped on each other, and said first seal protrusion is caused to fall to an inside of said air chamber in a state of being compressedly deformed, whereby a volume of said air chamber is decreased, so that an internal pressure is increased.

2. The fluid-filled vibration damping device according to claim 1, wherein said internal angle of the inside surface of said first seal protrusion is substantially set at a right angle or an obtuse angle.

3. The fluid-filled vibration damping device according to claim 1, wherein a housing portion having a concave portion or a hole for housing a portion of said first seal protrusion caused to fall to the air chamber side by compressed deformation is provided in an outer peripheral portion of said air chamber.

4. The fluid-filled vibration damping device according to claim 1, wherein a second seal protrusion formed of an elastic material is provided to project in the direction such that said cylindrical member and said bottom member are lapped on each other, to extend continuously in the circumferential direction so as to surround said first seal protrusion from the outside, and to have a cross-sectional shape parallel with the projecting direction so as not to fall easily at the time of compressed deformation caused by lapping of said bottom member on said cylindrical member.

5. The fluid-filled vibration damping device according to claim 1, wherein said seal member formed of the elastic material is provided at an outer peripheral portion of said flexible diaphragm, said flexible diaphragm is supported on said second mounting member in a state in which the lapped portions are sealed by holding said seal member between the lapped portions of said cylindrical member and said bottom member, said seal member, and further said first seal protrusion is integrally formed on the seal member of the flexible diaphragm.

6. The fluid-filled vibration damping device according to claim 1, wherein said bottom member consists of a one-side bottomed cylindrical body integrally having a cylindrical portion capable of being installed on said cylindrical member and a bottom portion that closes an opening on one side in the axial direction of the cylindrical portion, and said cylindrical portion is subjected to diameter-reducing operation in a state in which said cylindrical portion is installed on said cylindrical member and said bottom member is arranged so as to close an opening of said cylindrical member, whereby said bottom member is fixed in a state in which said bottom member is lapped on said cylindrical member, and said seal member is interposed between the cylindrical portion of the bottom member and the cylindrical member.

7. A seal structure for sealing an air chamber in a fluid-tight manner in a fluid-filled vibration damping device comprising: a first and a second mounting members which are spaced apart from each other; an elastic rubber body which elastically connects said first and second mounting members; a partition member supported by said second mounting member and cooperating with said elastic rubber body to define a pressure-receiving chamber which is filled with a non-compressible fluid and in which an internal pressure is changed by receiving an input vibrational load; a flexible diaphragm cooperating with said partition member to define an equilibrium chamber on one of the opposite sides of said partition member remote from said pressure-receiving chamber, said equilibrium chamber being filled with the fluid, and said flexible diaphragm being displaceable to permit a change in volume of said equilibrium chamber; an orifice passage provided to allow said pressure-receiving chamber and said equilibrium chamber to communicate with each other; and the air chamber filled with air with a pressure higher than an atmospheric pressure, formed on the opposite side to said equilibrium chamber, so as to hold said flexible diaphragm between said air chamber and said equilibrium chamber, and an air pressure in said air chamber being applied to said fluid in the equilibrium chamber, whereby the pressure of said fluid may be increased; wherein said second mounting member comprises a cylindrical portion formed on the second mounting member, the cylindrical portion having a cylindrical shape provided with a first opening that is open to the first mounting member side and a second opening that is open to the opposite side to the first mounting member, and supporting the partition member on the first mounting member side and supporting the flexible diaphragm on the opposite side to the first mounting member, and a closing member for closing the second opening of the cylindrical portion fixed to the cylindrical portion so as to be lapped on an end portion on the second opening side of the cylindrical portion, whereby the air chamber is formed between the closing member and the flexible diaphragm, wherein a seal member formed of an elastic material is disposed to be interposed between the lapped portions of the cylindrical portion and the closing member in a compressedly deformed state to seal the lapped portion in a fluid-tight manner;a seal protrusion having a chevron shape is formed by a part or a whole of the seal member, the seal protrusion projecting in the direction such that the cylindrical portion and the closing member are lapped on each other, extending continuously in a circumferential direction so as to surround the air chamber, and being configured so that a cross-sectional shape has an inside surface facing to the air chamber and an outside surface opposite to the inside surface, and an internal angle of the inside surface is larger than the internal angle of the outside surface so that the seal protrusion easily falls to the air chamber side at the time of compressed deformation caused by lapping of the closing member on the cylindrical portion; andeither one of the cylindrical portion and the closing member is brought into contact with a tip end portion of the seal protrusion in the seal member interposed between the cylindrical portion and the closing member, and from a state in which the air chamber, the air therein being incapable of going in from an outside and going out to the outside, is formed between the closing member and the flexible diaphragm, the cylindrical portion and the closing member are brought close to each other and lapped on each other, and the seal protrusion is caused to fall to an inside of the air chamber in a state of being compressedly deformed, whereby a volume of the air chamber is decreased, so that an internal pressure is increased to seal the air chamber in a fluid-tight manner in this state.