Spring devices – Resilient shock or vibration absorber – Nonmetallic – resilient element
Reexamination Certificate
2001-09-10
2003-09-09
Butler, Douglas C. (Department: 3683)
Spring devices
Resilient shock or vibration absorber
Nonmetallic, resilient element
C267S141200, C267S140500, C267S294000, C267S153000
Reexamination Certificate
active
06616130
ABSTRACT:
INCORPORATION BY REFERENCE
The disclosure of Japanese Patent Application No. 2000-272594 filed on Sep. 8, 2000 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a cylindrical vibration-isolating device which includes an inner metal sleeve and an outer metal sleeve that are disposed in a radially spaced-apart relation with each other and are elastically connected to each other by an elastic body interposed therebetween, and which is interposed between two members of a vibration system for connecting these two members in a vibration-isolating fashion. More specifically, the present invention is concerned with such a cylindrical vibration-isolating device which includes a sealing-rubber member adapted to seal a bore of the inner metal sleeve so that entrance of water or other objects into the bore of the inner metal sleeve is effectively prevented, with the vibration-isolating device is installed between the two members of the vibration system.
2. Description of the Related Art
A cylindrical vibration-isolating device is known as one type of a vibration damping or isolating mount that is interposed between two members of a vibration system for flexibly connecting the two members in a vibration damping or isolating fashion. The cylindrical vibration-isolating device comprises an inner metal sleeve and an outer metal sleeve disposed radially outwardly of an inner metal sleeve with a suitable radial spacing therebetween and an rubber elastic body interposed between and elastically connecting the inner and outer metal sleeves. For instance, this cylindrical vibration-isolating device may be used in an automotive vehicle as a member mount such as a suspension member, a deferential mount, a body mount, a suspension bush or the like.
Generally, the cylindrical vibration-isolating device is installed between one and the other members of the vibration system such that the inner metal sleeve is fixed to the one member by a mounting bolt or rod fixedly formed in the one member and extending through the bore of the inner metal sleeve, while the outer metal sleeve is forcedly pressed into a fixing bore formed in the other member. In this condition, the inner metal sleeve is fastened in its axial direction between the one member and a washer, which are held in pressing contact with opposite axial end faces of the inner metal sleeve, respectively. Therefore, water is likely to enter into the bore of the inner metal sleeve through a gap between the one member or washer and the corresponding end face of the inner metal sleeve, thus causing rust of the device and resultant deterioration of strength or durability of the device.
To cope with this problem, it has been proposed to provide a thin sealing rubber layer on at least the one end face of the inner metal sleeve which is held in contact with the one member, so that the sealing rubber layer is compressed by and between the one end face of the inner metal sleeve and the one member.
However, the sealing rubber layer compressed by and between the end face of the inner metal sleeve and the one member is prone to suffer from fatigue or wear thereof due to a load and sliding frictional force continuously applied thereto. This leads to early deterioration of sealing capability of the sealing rubber layer. It is therefore difficult to ensure a fluid-tight sealing between the end face of the inner metal sleeve and the one member for a long period of time.
Examples of various types of known sealing members for the cylindrical vibration-isolating device are disclosed in JP-U-57-165827. A first example is a sealing projection which is integrally formed on one of axially opposite end faces of the elastic body. A second example is a sealing projection which is independent of the elastic body, and is formed on and protrudes outwardly from an outer circumferential surface of one of axially opposite end portions of the inner metal sleeve. In the first example, since the sealing projection is integrally formed with the elastic body, the sealing projection is affected by elastic deformation of the elastic body. Thus, the sealing projection of the first example is incapable of exhibiting a stable sealing capability. In the second example, since the sealing projection is formed independently of the elastic body, molding of the sealing projection and the elastic body becomes cumbersome. Further, the sealing projection of the second example is likely to suffer from stress concentration at a bonding surface thereof to the inner metal sleeve, thus causing occurrence of cracks in the sealing projection and separation in the interface between the sealing projection and the inner metal sleeve. Thus, the sealing projection of the second example is insufficient in terms of durability.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a cylindrical vibration-isolating device which includes a novel sealing structure capable of preventing entrance of water into a bore of an inner metal sleeve with high stability for a long period of time.
The above object may be attained according to the following modes of the invention, each of which is numbered like the appended claims and depends from the other mode or modes, where appropriate, to indicate possible combinations of elements or technical features of the invention. It is to be understood that the present invention is not limited to the following modes or combinations of technical features, but may otherwise be recognized based on the thought of the present invention that described in the whole specification and drawings or that may be recognized by those skilled in the art in the light of the disclosure in the whole specification and drawings.
(1) A cylindrical vibration-isolating device comprising: (a) an inner metal sleeve; (b) an outer metal sleeve disposed radially outwardly of the inner metal sleeve with a radial spacing therebetween; (c) an elastic body interposed between and elastically connecting the inner metal sleeve and the outer metal sleeve, such that at least one of axially opposite end portions of the inner metal sleeve is located axially outward of the elastic body; (d) a connecting rubber layer integrally formed with and protruding axially outwardly from the elastic body, said connecting rubber layer having a thin-walled cylindrical shape and being secured to an outer circumferential surface of the at least one of axially opposite end portions of the inner metal sleeve; and (e) an annular sealing-rubber member formed integrally with and protruding axially outwardly from a protruding end portion of the connecting rubber layer, the annular sealing-rubber member protruding axially outwardly from a corresponding end face of the inner metal sleeve, the annular sealing-rubber member having a radially inner base portion which has a concave surface and rises from a first axial position on the outer circumferential surface of the at least one of axially opposite end portions of said inner metal sleeve, which first axial position is axially inwardly spaced apart from the corresponding end face of the inner metal sleeve.
In the vibration-isolating device according to the above mode (1) of the invention, the annular sealing-rubber member, which is provided on the outer circumferential surface of the at least one of axially opposite end portions of the inner metal sleeve which is located axially outward of the elastic body, is integrally connected and formed with the elastic body via the connecting rubber layer which is secured to the outer circumferential surface of the at least one of axially opposite end portion of the inner metal sleeve. According to this structure, the annular sealing-rubber member can be simultaneously formed with the elastic body with ease and firmly secured to the inner metal sleeve. Further, the presence of the connecting rubber, which is thin and secured to the outer circumferential surface of the inner metal s
Hokazono Kiyoshi
Kawakatsu Fukuyoshi
Butler Douglas C.
Rossi & Associates
Tokai Rubber Industries Ltd.
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