Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2002-09-10
2004-04-06
Knight, Anthony (Department: 3676)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C267S219000, C267S140120, C277S916000
Reexamination Certificate
active
06715745
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a liquid-sealed mount.
BACKGROUND ART
In a working vehicle such as a hydraulic shovel, a cab is mounted on a vehicle body frame via a liquid-sealed mount to reduce transmissibility of vibrations and impacts, which occur during a working operation and traveling, to a cab.
FIG. 10
is a sectional view showing a first example of a conventional liquid-sealed mount. A damping member
34
attached at a lower end of a stud
33
is housed inside a cylindrical case
31
having a bottom face. The dumping member
34
is formed into a disc-shape having a little smaller diameter than an inner diameter of the case
31
to form a ring-shaped clearance between an outer circumferential portion thereof and the case
31
. The stud
33
is attached at a position of an axis of a cylindrical elastic body
36
inserted in the case
31
, and is held by the case
31
via the cylindrical elastic body
36
. A recessed portion
36
a
is formed on an undersurface of the elastic body
36
. A viscous liquid L is sealed up to a midpoint of the recessed portion
36
a
inside the case
31
sealed by the elastic body
36
, and an air chamber sealed by the viscous liquid L is formed in an upper part in the recessed portion
36
a.
The case
31
and the stud
33
are mounted to either the cab or the vehicle body frame, respectively. Vibrations and impacts occurring to the vehicle relatively move the case
31
and the stud
33
, and the damping member
34
agitates the viscous liquid L. A damping force occurring at this time causes a buffering action to work, which reduces the vibrations and impacts transmitted to the cab.
FIG. 11
shows a second example of the conventional liquid-sealed mount, which is a sectional view showing a liquid-sealed mount disclosed in Japanese Patent Laid-open No. 7-127683 that can prevent breakage of an elastic body even when a large load acts thereon to cause a large displacement.
A damping member
44
attached to a lower end of a stud
43
is housed inside a cylindrical case
41
having a bottom face. The damping member
44
, which has an orifice hole
44
a
vertically penetrating it, forms a disc-shape having a little smaller diameter than an inner diameter of the case
41
, and a ring-shaped clearance is formed between an outer circumferential portion thereof and the case
41
. A coil spring
48
is provided between the case
41
and the damping member
44
, and upper and lower ends thereof are connected to the bottom face of the case
41
and the damping member
44
, respectively. A sleeve
47
is attached to an inner circumference of a cylindrical elastic body
46
attached in an upper part of the case
41
, and the stud
43
is hermetically in contact with an inner circumference of the sleeve
47
and is held to be vertically slidable. A bellows
49
is integrally formed at a lower end of the elastic body
46
, and a lower end portion of the bellows
49
is hermetically attached to an attached portion of the damping member
44
and the stud
43
. The viscous liquid L is scaled inside the case
41
sealed by the elastic body
46
, the bellows
49
and the damping member
44
.
Even if a large load acts on the stud
43
, it is supported by the spring
48
and the load does not act on the elastic body
46
, and therefore breakage of the elastic body
46
can be prevented. Cushioning, in a vertical direction is performed by the dumping member
44
and the spring
48
, and cushioning in a lateral direction is performed by the elastic body
46
. Both of the cushioning actions reduce the vibrations and impacts transmitted to the cab.
However, the above-described conventional liquid-sealed mount has the following disadvantages.
The damping force is caused by pressure loss of the viscous liquid L which is throttled in the clearance from the cases
31
and
41
due to a pressure difference between upper sides and lower sides to the damping members
34
and
44
to flow. Consequently, in the direction in which the studs
33
and
43
descend, the lower sides of the damping members
34
and
44
are at high pressure and the pressure difference from the upper side becomes large, thus making it possible to obtain a large damping force. However, in the direction in which the studs
33
and
43
ascend, the air inside the recessed portion
36
a
is compressed in the first example of the prior art, and the air inside the bellows
49
is compressed to contract the bellows
49
in the second example of the prior art. Therefore, the upper sides of the damping members
34
and
44
are never at sufficient high pressure. Consequently, the pressure differences between the upper sides and the lower sides of the damping members
34
and
44
cannot be sufficiently large, and the damping force is reduced.
Further, when a large load in a rising direction is exerted on the studs
33
and
43
, the pressure in the upper sides of the damping members
34
and
44
do not become sufficiently high, and the pressure differences corresponding to the load occur between both sides of the damping members
34
and
44
. As a result, the pressure in the lower sides of the damping members
34
and
44
is reduced to cause cavitation, and the flow of the viscous liquid L flowing through the aforementioned clearance is extremely reduced, thus reducing the damping force to a large extent.
SUMMARY OF THE INVENTION
To eliminate the above-described disadvantage, the present invention has its object to provide a liquid-sealed mount, which is capable of obtaining excellent damping performance.
In order to attain the above-described object, the liquid-scaled mount according to the present invention has a constitution including
an elastic body,
a stud penetrating through the elastic body;
a case, which is in a cylindrical shape with one end side being opened and with a bottom face on the other end side, houses a viscous liquid in an inside thereof, and which the viscous liquid is sealed in by fitting the elastic body and the stud into the opening at the one end side, and
a damping member attached to the stud in a state in which the damping member submerges in the viscous liquid,
wherein a wall surface of a portion, which submerges in the viscous liquid, of the case is formed so that an inner diameter gradually decreases toward a lower position and an angle of inclination is different in an upper part from a lower part, and an outer circumferential side surface of the damping member opposes the inclined surface of the case.
According to the above constitution, the clearance between the case and the outer circumferential side surface of the damping member is gradually narrowed following the descent of the stud (namely, the descent of the damping member), and therefore the damping force caused by pressure loss of the viscous liquid passing through this clearance can be smoothly made larger, and a large damping force can be obtained according to the vibration width, namely, when the width of vibration is large. Further, the angle of inclination of the inclined surface of the case is formed in a plurality of stages, whereby the damping force can be changed in the multiple stages, and therefore the impact that occurs at the time of abutment against the stopper can be cushioned by setting the damping force to be large before the stud or the like abuts against the stopper. The damping force can be set optionally by optionally setting a plurality of angles of inclination of the case.
Further, in the liquid sealed mount, the constitution in which an outer diameter of the damping member is larger in a lower part than in an upper part may be suitable. According to the above constitution, for the vibration in the lateral direction, which oscillates the upper end portion of the stud, the resultant force of the reaction force, which controls and diminishes the vibration, acts on the lower part of the damping member, and thus a profound vibration controlling effect can be obtained.
REFERENCES:
patent: 4610438 (1986-09-01), Eberhard et al.
patent: 5516176 (1996-05-01), Kimoto et al.
patent: 5707
Kuzukawa Mitsuo
Nakada Kuniaki
Knight Anthony
Komatsu Ltd.
Patel Vishal
Rader & Fishman & Grauer, PLLC
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