Liquid-encapsulated damper mount

Details Liquid-encapsulated damper mount Liquid-encapsulated damper mount

1999-02-16

2002-08-06

Rodriguez, Pam (Department: 3683)

Brakes

Internal-resistance motion retarder

Including means connecting thrust member to load

C267S220000, C280S124147

Reexamination Certificate

active

06427814

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid-encapsulated damper mount for supporting, on a vehicle body, an upper end of a damper which suspends a wheel of the vehicle.
2. Description of the Related Art
A liquid-encapsulated damper mount is already known from Japanese Utility Model Publication No. 7-49098.
FIG. 14
shows the structure of the above known liquid-encapsulated damper mount. An inner member or shell
01
fixed to an upper end of a damper (not shown) and an outer member or shell
02
fixed to a vehicle body (not shown), are connected to each other by a first elastomer member
03
and a second elastomer member
04
, thereby defining a liquid chamber
05
having a non-compressible liquid encapsulated therein, between the first and second elastomer members
03
and
04
. A partition member
06
is disposed within the liquid chamber
05
, and the liquid chamber
05
is divided into an upper chamber portion
08
and a lower chamber portion
09
through a restriction
07
defined between an outer peripheral surface of the partition member
06
and an inner peripheral surface of the first elastomer member
03
.
When the inner member
01
and the outer member
02
are moved relative to each other by a load transmitted from the wheel via the damper to the liquid-encapsulated damper mount to deform the first and second elastomer members
03
and
04
, the volumes of the upper and lower chamber portions
08
and
09
are alternately increased and decreased, whereby the liquid is reciprocally moved through the restriction
07
. In this case, the dynamic spring constant at middle and higher frequency ranges can be reduced by the liquid column resonance effect generated in the restriction to contribute to a reduction in load noise.
When a load at a very low speed (e.g., 0.03 m/sec or less) is inputted from the wheel to the damper during traveling of the vehicle on a relatively flat paved road surface, the friction between a piston and a cylinder of the damper is unstable under the influence of the individual differences in oil seals or a change in oil seal with the passage of time, thereby resulting in a problem in that sufficient damping is not obtained in a hydraulic valve of the damper, and an unsprung portion of the vehicle suspension causes a resonance which degrades the riding comfort. In other words, if the friction component of the damper has a large value in
FIG. 15
which is a model diagram of the vibration system including the damper and the liquiden-capsulated damper mount in combination, when the load of the very low speed is inputted, a damping component (a dash pot component) caused by the passage of working oil through the hydraulic valve of the damper can not be generated in a normal fashion, thereby providing a degradation in riding comfort.
It is conceived that when the load of the very low speed is inputted, a damping force is generated by the liquid-encapsulated damper mount rather than by the damper. For this purpose, the cross-sectional area of the restriction of the liquid-encapsulated damper mount may be set at a sufficient small value, and a damping component may be generated when the liquid flows through the restriction.
However, the prior art liquid-encapsulated damper mount shown in
FIG. 14
suffers from the following problem: The restriction
07
is defined by the clearance between the outer peripheral surface of the partition member
06
and the inner peripheral surface of the first elastomer member
03
, and when a load from the damper is inputted in an oblique direction, the contact between the outer peripheral surface of the partition member
06
and the inner peripheral surface of the first elastomer member
03
must be avoided. For this reason, it is difficult to decrease the cross-sectional area of the restriction
07
.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to ensure that when a load of a very low speed is inputted from a road surface, a sufficient damping force is generated in the liquid-encapsulated damper mount, thereby enhancing the riding comfort during traveling of the vehicle on a flat road.
To achieve the above object, according to a first aspect and feature of the present invention, there is provided a liquid-encapsulated damper mount comprising an outer member fixed to a vehicle body, an inner member fixed to an upper end of a damper which suspends a wheel of a vehicle, an elastomer member connecting the inner member and the outer member for supporting the upper end of the damper on the vehicle body. A first liquid chamber and a second liquid chamber are defined within the elastomer, to communicate with each other through a restriction, the restriction being defined to penetrate one of an inside of a rigid member and an inside of the elastomer member.
With the above arrangement, the restriction interconnecting the first and second liquid chambers defined within the elastomer member of the liquid-encapsulated damper mount, is defined to penetrate the inside of the rigid member or the inside of the elastomer member. Therefore, even if the cross-sectional area of the restriction is set at a sufficiently small value, so that a damping force corresponding to the inputting of a load of a very low speed is generated, the cross-sectional area of the restriction can be prevented from being changed by the load, whereby a stable damping force is generated to enhance the riding comfort during traveling of the vehicle on a flat road.
The rigid member is, for example, a member formed from a metal or a hard synthetic resin, i.e., may be any material, if the material is not deformed by inputting of a load.
According to a second aspect and feature of the present invention, the rigid member comprises the inner member and a ring member which is fitted over an outer periphery of the inner member and connected to an inner periphery of the elastomer member. The restriction is defined in abutting faces of the inner member and the ring member.
With the above arrangement, the restriction is defined in the abutting faces of the inner member and the ring member. Therefore, the restriction can be easily formed by the step of only defining a groove in at least one of the inner member and the ring member and moreover, a special member for defining the restriction is not required, leading to a reduction in number of parts.
According to a third aspect and feature of the present invention, a system loss factor is set, such that the loss factor has a peak value when the frequency of vibration inputted from the wheel is in the vicinity of the natural frequency of an unsprung portion of a suspension.
With the above arrangement, when the frequency of vibration inputted from the wheel becomes a value in the vicinity of the natural frequency of the unsprung portion of the suspension, the value of the loss factor is peaked to generate a larger damping and hence, the resonance of the suspension can be prevented, to thereby enhance the riding comfort.
The term “loss factor tan &dgr;” is defined as a tangent of a loss angle between the stress and the strain of a system which is being forcibly vibrated. The vicinity of the natural frequency of the unsprung portion of the suspension is defined to indicate a range of 0.7 f
0
to 1.4 f
0
, wherein f
0
represents the natural frequency.
According to a fourth aspect and feature of the present invention, a stopper for limiting the maximum relative displacement of the outer member and the inner member is formed integrally with the elastomer member.
With the above arrangement, since the stopper for limiting the maximum relative displacement of the outer member and the inner member is formed integrally with the elastomer member, the number of parts can be reduced, as compared with the case where the stopper is provided separately from the elastomer member.
The above and other objects, features and advantages of the invention will become apparent from the following description of the preferred embodiments taken in conjunction with the accomp

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