Spring devices – Resilient shock or vibration absorber – Nonmetallic – resilient element
Reexamination Certificate
1999-03-17
2001-04-10
Graham, Matthew C. (Department: 3613)
Spring devices
Resilient shock or vibration absorber
Nonmetallic, resilient element
C267S140120, C267S293000
Reexamination Certificate
active
06213455
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vibration isolator used suitably as, for example, an engine mount which vibroisolatingly supports an engine unit to be mounted on a vehicle.
2. Description of the Related Art
Conventionally, when an engine unit is mounted on a vehicle, such a vibration isolator as an engine mount is employed to support the engine unit vibroisolatingly, in order to suppress vibrations generated at the engine unit from being transmitted to a car body. An example of the conventional engine mount of this type is shown in
FIGS. 11
to
13
.
This engine mount comprises a cylindrical inner member
5
; a mounting member
6
having a tubular portion
61
which is disposed outside of and at a distance from the inner member
5
approximately coaxially with the inner member
5
, and two mounting seat portions
62
,
63
which are integrally formed at an outer periphery of the tubular portion
61
; a rubber elastic body
7
disposed between and connecting integrally the inner member
5
and the tubular portion
61
, and having axially through cavity portions
71
,
72
; and an elastic stopper
8
projecting from an inner circumferential surface of the tubular portion
61
in a manner to face the inner member
5
by way of one cavity portion
71
. At a portion of the tubular portion
61
where the elastic stopper
8
is formed, there are side stoppers
65
,
65
extending in axially opposite directions and having the same thickness as the tubular portion
61
. On the surface of each of the side stoppers
65
,
65
, there is disposed a thin portion
85
of the elastic stopper
8
.
This engine mount is secured by fixing one of the inner member
5
and the mounting member
6
to an engine unit and fixing the other to a car body. In this case, the elastic stopper
8
is placed so as to stand in a main vibration input direction, and fore ends of brackets
55
,
55
which are connected to both the ends of the inner member
5
are provided so as to face the side stoppers
65
,
65
.
When vibrations are input from the engine unit to the engine mount, the rubber elastic body
7
disposed between the inner member
5
and the tubular portion
61
of the mounting member
6
is deformed elastically, thereby damping the vibrations effectively. When relatively weak vibrations are input, the elastic stopper
8
is compressed by the inner member and the tubular portion
61
, whereby relative displacement of the inner member
5
and the mounting member
6
is restricted elastically and vibration transmitting power is reduced effectively.
When strong vibrations are input, the fore ends of the brackets
55
,
55
which are connected to both the ends of the inner member
5
come in contact with the thin portions
85
,
85
of the elastic stopper
8
which are placed on the side stoppers
65
,
65
. Thus, excessive relative displacement of the inner member
5
and the mounting member
6
is restricted, and the rubber elastic body
7
and the elastic stopper
8
are prevented from being excessively deformed, so superior durability is secured.
By the way, the above conventional engine mount uses the brackets
55
,
55
which are connected to both the ends of the inner member
5
, and the side stoppers
65
,
65
which extend in the axially opposite directions from the tubular portion
61
of the mounting member
6
, as a stopper structure for restricting excessive relative displacement of the inner member
5
and the mounting member
6
when strong vibrations are input.
Because the side stoppers
65
,
65
project axially, the tubular portion
61
of the mounting member
6
is increased in size. Besides, since the shape and size of the side stoppers
65
,
65
must be determined in accordance with the shape and size of the brackets
55
,
55
connected to the inner member
5
, a lot of limitations are imposed on the design and the stopper structure becomes complicated.
SUMMARY OF THE INVENTION
The present invention has been conceived to dissolve these inconveniences.
It is an object of the present invention to provide a vibration isolator which achieves both a reduction in the vibration transmitting power and superior durability of an elastic stopper.
It is another object of the present invention to provide a vibration isolator which has a compact stopper structure.
A vibration isolator according to the first aspect of the present invention, which dissolves the above inconveniences, comprises: an inner member; a mounting member having a tubular portion which is disposed outside of and at a distance from the inner member approximately coaxially with the inner member; a rubber elastic body disposed between and connecting integrally the inner member and the tubular portion, and having an axially through cavity portion; and an elastic stopper projecting from an inner circumferential surface of the tubular portion in a manner to face the inner member by way of the cavity portion, wherein the tubular portion has side stoppers which are disposed at both the axial ends of a portion where the elastic stopper is formed, in a manner to face the inner member, and which form therebetween a concave portion depressed in a radially outward direction; and the elastic stopper has a projection base portion which is embedded in the concave portion and which projects in a radially outward direction from fore end surfaces of the side stoppers.
According to the first aspect of the present invention, since the side stoppers for restricting excessive relative displacement of the inner member and the mounting member are disposed at both the axial ends of a portion of the tubular portion where the elastic stopper is formed, in a manner to face the inner member, the vibration isolator can have a compact shape in which the tubular portion doesn't protrude axially. In addition, since the elastic stopper for restricting elastically the relative displacement of the inner member and the mounting member is arranged in such a way that the projection base portion is embedded in the concave portion formed between both the side stoppers. Owing to this projection base portion, the elastic stopper can attain a sufficiently large thickness (volume) and, as a result, the vibration transmitting power can be decreased effectively.
Thus, according to the first aspect of the present invention, the vibration isolator can attain both a reduction in the vibration transmitting power and superior durability of the elastic stopper, and can have a compact stopper structure.
In the present invention, the side stoppers provided at the tubular portion of the mounting member are constituted by rigid bodies having an appropriate strength, and, for example, can be formed of metal, synthetic resin, or the like integrally with the tubular portion.
A vibration isolator according to the second aspect of the present invention has a construction wherein, in the first aspect of the present invention, the mounting member is formed of synthetic resin.
According to this aspect of the present invention, since the mounting member including the tubular portion and the side stoppers is formed of a lightweight synthetic resin, the mounting member can be sufficiently reduced in weight. A polyamide resin, for example, 6,6-nylon can be suitably employed as a synthetic resin in view of strength. This synthetic resin may be improved in strength by being filled with such a reinforcing fiber as glass fiber.
A vibration isolator according to the third aspect of the present invention has a construction wherein, in the second aspect of the present invention, the mounting member is formed by placing at least the elastic stopper in a molding die and carrying out injection molding, and the side stoppers are formed of synthetic resin integrally with the tubular portion.
According to this aspect of the present invention, since the elastic stopper is disposed between the side stoppers which are to be axially arranged in the molding die, the direction of removing the molding die can be set as an axial direction. Thus, the sid
Kato Kazuhiko
Suzuki Tatsuya
Graham Matthew C.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Sy Mariano
Tokai Rubber Industries Ltd.
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