Vibration-damping device for vehicles and method of manufacturing the same

• US 20050253317A1
• Filed: 05/10/2005
• Published: 11/17/2005
• Est. Priority Date: 05/14/2004
• Status: Active Grant

• Current Assignee: Tokai Rubber Industries Limited
• Original Assignee: Tokai Rubber Industries Limited
• Inventors: Maeda, Kouichi, Yasumoto, Yoshinori
• Granted Patent: US 7,267,740 B2
• Time in Patent Office: Days
• US Class Current: 267/140.110
• CPC Class Codes: F16F 7/108 on plastics springs
• CPC Class Codes: Y10T 29/49615 Resilient shock or vibration absorber utility

Abstract

A vehicle vibration-damping device including a rigid housing and an independent mass member housed in the housing and having a metallic mass of circular shape in section and a rubber elastic body layer adhered to the metallic mass. A distance of a gap between opposing surfaces of the housing and the metallic mass in the radial direction, with the housing and metallic mass disposed coaxially, is set to between 0.5 and 2 mm. The rubber elastic body layer is formed around an entire outer peripheral surface of the metallic mass by a vulcanization molding of a rubber material filling the gap, and thermal contraction is used both to cause the rubber elastic body layer to peel from the housing and to cause it to adhere onto the outer peripheral surface of the metallic mass to thereby fabricate a small gap of no more than 0.1 mm. A method of manufacturing the same is also disclosed.

Claims

1. A vehicle vibration-damping device adapted to be installed on a vibrating member to damp vibrations excited therein, comprising:

a rigid housing having a cylindrical inner peripheral surface, that is adapted to be attached to the vibrating member; and

an independent mass member including a metallic mass having a circular shape in cross section, and a rubber elastic body layer adhered to an outer peripheral surface of the metallic mass, the independent mass member being housed within the housing with a gap therebetween in a radial direction corresponding to a primary vibration input direction so that the independent mass member is movable relative to the housing in the primary vibration input direction, the vibration-damping device being capable of exhibiting a vibration-damping effect based on the independent mass member moving relative to the housing, and striking the housing, when a vibration is applied,

wherein a distance between opposing surfaces of the inner peripheral surface of the housing and the outer peripheral surface of the metallic mass in the radial direction, when the housing and metallic mass are disposed coaxially, is set to between 0.5 and 2 mm, and

wherein the rubber elastic body layer is formed around an entire outer peripheral surface of the metallic mass by a vulcanization molding of a rubber material filling the gap between the inner peripheral surface of the housing and the outer peripheral surface of the metallic mass, and thermal contraction is used both to cause the rubber elastic body layer to peel from the housing and to cause it to adhere onto the outer peripheral surface of the metallic mass to thereby fabricate a small gap of no more than 0.1 mm, between the opposing surfaces, when the rubber elastic layer member and the housing are disposed coaxially, so that a natural frequency of the independent mass member is set to a frequency band that is higher than a natural frequency of the vibrating member so that the metallic mass is repetitively strike the inner surface of the housing on both sides in the primary vibration input direction through the rubber elastic body layer when a vibration is applied.

2. A vehicle vibration-damping device according to claim 1, wherein the vibration-damping device is disposed in a state where the primary vibration input direction is approximately vertically oriented, and when the vibration-damping device is subjected to at least 2G input vibration, the independent mass member undergoes repetitive strike against the inner peripheral surface of the housing on both sides in the primary vibration input direction.

3. A vehicle vibration-damping device according to claim 1, wherein at least one through hole is fabricated in the housing in a position that avoids the part wherein the independent mass member strikes the housing when a vibration is applied in the primary vibration input direction.

4. A vehicle vibration-damping device according to claim 1, wherein an outer peripheral surface of the rubber elastic body layer and the inner peripheral surface of the housing are fabricated so as to extend in the axial direction with approximately uniform cross sections so that the small gap that is fabricated between the outer peripheral surface of the rubber elastic body layer and the inner peripheral surface of the housing is approximately uniform along the entire length in the axial direction.

5. A method of manufacturing a vehicle vibration-damping device comprising:

(a) a gap fabricating process that fabricates a gap of 0.5-2 mm between an inner peripheral surface of a rigid housing and an outer peripheral surface of a metallic mass, by rigidly positioning the housing having an inner peripheral surface of cylindrical shape and the metallic mass having a cylindrical cross section, relative to a vulcanization fabrication mold for fabricating a rubber elastic body layer, while by disposing the metallic mass coaxially disposed within the housing;

(b) a rubber elastic body layer fabricating process wherein a rubber material is filled into the gap, and then is vulcanized to mold the rubber material within a mold cavity that is formed between the housing and the metallic mass in order to fabricate the rubber elastic body layer; and

(c) a small gap fabricating process that fabricates a small gap of no more than 0.1 mm between the outer peripheral surface of the rubber elastic body layer and the inner peripheral surface of the housing that are opposed to each other in a radial direction, under a condition of the metallic mass being disposed coaxially within the housing, by utilizing a thermal contraction of the rubber elastic body layer to both peel the rubber elastic body layer from the housing and to adhere the rubber elastic body layer by means of reduction of an diameter thereof towards the metallic mass,

wherein a natural frequency of the independent mass member that is formed by a tight adherence of the rubber elastic body layer to the outer peripheral surface of the metallic mass is set to be at a frequency band that is higher than a frequency of a target vibration that is to be damped for a vibrating member so that, upon application of the target vibration, the independent mass member repetitively strikes the inner surfaces of the housing on both sides in a primary vibration input direction.

6. A method of manufacturing a vehicle vibration-damping device according to claim 5, further comprising a preliminary process that performs at least one of an adhesion treatment for ensuring an adhesion of the rubber elastic body layer to the metallic mass, and a non-adhesion treatment for ensuring a non-adhesion of the rubber elastic body layer to the housing, prior to the rubber elastic body layer fabricating process.

7. A method of manufacturing a vehicle vibration-damping device according to claim 5, further comprising a release process that forcibly causes a relative movement between the rubber elastic body layer and the housing, in at least one of a circumferential direction and an axial direction, and that is executed posterior to the rubber elastic body layer fabricating process.