U.S. patent application number 12/181081 was filed with the patent office on 2009-02-05 for suspension apparatus for washing machine and washing machine having the same.
Invention is credited to Kyung-Mun Jong, Young-Jong KIM.
Application Number | 20090031761 12/181081 |
Document ID | / |
Family ID | 40336854 |
Filed Date | 2009-02-05 |
United States Patent
Application |
20090031761 |
Kind Code |
A1 |
KIM; Young-Jong ; et
al. |
February 5, 2009 |
SUSPENSION APPARATUS FOR WASHING MACHINE AND WASHING MACHINE HAVING
THE SAME
Abstract
A suspension apparatus for a washing machine comprises: a pivot
mounted to a casing; a damper cap mounted to an outer tub installed
in the casing; a connection rod having the pivot and the damper cap
at both ends thereof; and an elastic means formed in the damper
cap, wherein a contact area decreasing portion for reducing a
contact area on the surface of the pivot is formed on the pivot.
Under this configuration, vibration or noise transmitted to a
mounting surface for the pivot is reduced.
Inventors: |
KIM; Young-Jong;
(Gyeongsangnam-Do, KR) ; Jong; Kyung-Mun;
(Gyeongsangnam-Do, KR) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
40336854 |
Appl. No.: |
12/181081 |
Filed: |
July 28, 2008 |
Current U.S.
Class: |
68/23.1 |
Current CPC
Class: |
D06F 37/20 20130101;
D06F 37/24 20130101 |
Class at
Publication: |
68/23.1 |
International
Class: |
D06F 37/20 20060101
D06F037/20 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 30, 2007 |
KR |
10-2007-0076582 |
Claims
1. A suspension apparatus for a washing machine, comprising: a
pivot mounted to a casing; a damper cap mounted to an outer tub
installed in the casing; a connection rod having the pivot and the
damper cap at both ends thereof; and an elastic means formed in the
damper cap, wherein a contact area decreasing portion for reducing
a contact area on the surface of the pivot is formed on the
pivot.
2. The apparatus of claim 1, wherein the elastic means is a damper
spring.
3. The apparatus of claim 1, wherein the contact area decreasing
portion includes dimples concavely formed on the surface of the
pivot.
4. The apparatus of claim 1, wherein the contact area decreasing
portion includes a groove formed on the surface of the pivot.
5. The apparatus of claim 1, wherein a lubricant is deposited to
the contact area decreasing portion.
6. The apparatus of claim 5, wherein a damper base sliding along an
inner surface of the damper cap and supporting one end of the
connection rod is provided in the damper cap, wherein below the
damper base, mounted is an extension spring for uniformly
maintaining an air gap between the damper base and the damper cap,
and thereby increasing a viscous damping force by air leaked
through the air gap.
7. The apparatus of claim 6, wherein the extension spring
consecutively contacts a lower side surface of the damper base.
8. The apparatus of claim 7, further comprising a base cap mounted
to a lower side of the damper cap, and configured to reduce a
leakage amount of air inside the damper cap.
9. A washing machine having a suspension apparatus, the washing
machine comprising a casing, an outer tub installed in the casing,
and a suspension apparatus installed between the casing and the
outer tub, wherein the suspension apparatus comprises: a pivot
mounted to the casing; a damper cap mounted to the outer tub
installed in the casing; a connection rod having the pivot and the
damper cap at both ends thereof; and an elastic means formed in the
damper cap, wherein a contact area decreasing portion for reducing
a contact area between the pivot and the casing is formed on the
surface of either the casing, or the pivot.
10. The washing machine of claim 9, wherein the elastic means is a
damper spring.
11. The washing machine of claim 9, wherein the contact area
decreasing portion includes concaved dimples or grooves.
12. The washing machine of claim 9, wherein a lubricant is
deposited to the contact area decreasing portion.
13. The washing machine of claim 12, wherein the suspension
apparatus further comprises a base cap mounted to a lower side of
the damper cap, and configured to reduce a leakage amount of air
inside the damper cap.
14. The washing machine of claim 13, wherein an air hole for a
viscous damping is formed at either the damper cap or the base
cap.
15. The washing machine of claim 12, wherein a damper base sliding
along an inner surface of the damper cap and supporting one end of
the connection rod is provided in the damper cap, wherein below the
damper base, mounted is an extension spring for uniformly
maintaining an air gap between the damper base and the damper cap,
and thereby increasing a viscous damping force by air leaked
through the air gap.
Description
RELATED APPLICATION
[0001] The present invention relates to subject matter contained in
priority Korean Application No. 10-2007-0076582, filed on Jul. 30,
2007, which is herein expressly incorporated by reference in its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a washing machine, and more
particularly, to a suspension apparatus for a washing machine
capable of reducing vibration or noise transmitted to a body of a
washing machine from an outer tub, by forming a contact area
decreasing portion on either an upper pivot or a mounting surface
for the upper pivot so as to decrease a contact area therebetween,
and thereby allowing lubricant deposited onto the contact area
decreasing portion to stay for a long time, and a washing machine
having the same.
[0004] 2. Description of the Background Art
[0005] Generally, a washing machine serves to wash laundry by using
a softening process by detergent, a frictional process by water
stream occurring as washing blades rotate, an impact process by
washing blades, etc. By using a motor as a main driving force, the
washing machine performs a washing process, a rinsing process, and
a dehydrating process so as to wash laundry with using detergent
and water. The washing machine comprises a motor serving as a
driving unit, a mechanical part for transmitting energy to laundry,
a controller for controlling washing processes, a water supply unit
for supplying water, and a water drain unit for discharging
water.
[0006] The washing machine is largely divided into a cylinder type,
an agitator type, and a pulsator type according to washing
methods.
[0007] According to the agitator type, an agitator protruding from
the center of an inner tub with a wing shape is rotated in right
and left directions thus to wash laundry. According to the pulsator
type, laundry is washed by using turbulent stream occurring as a
disc-shaped pulsator is rotated. According to the cylinder type,
water, detergent, and laundry are put into a drum having a
plurality of protrusions, and then are rotated with a low speed in
a horizontal axis, thereby washing laundry by an impact occurring
as the laundry is lifted and dropped by the protrusions.
[0008] FIG. 1 is a schematic sectional view of a washing machine in
accordance with the related art, FIG. 2 is a schematic sectional
view of a suspension apparatus for a washing machine in accordance
with the related art, and FIG. 3 is an enlarged sectional view of
`A` of FIG. 2.
[0009] Referring to FIG. 1, a washing machine 1 comprises a body or
a casing 10 that forms appearance; an outer tub 12 mounted in the
casing 10; an inner tub 13 mounted in the outer tub 12; a
suspension apparatus 20 or suspensions each having one end
connected to an upper inner circumferential surface of the body or
the casing 10, having another end connected to a lower outer
circumferential surface of the outer tub 12, and configured to
support the outer tub 12; and a driving unit 15 disposed below the
outer tub 12, and configured to drive the inner tub 13.
[0010] Referring to FIG. 2, each of the suspensions 20 comprises a
damper cap 22 installed below the outer tub 12; a connection rod 21
having one end penetrating the damper cap 22, and another end
disposed at an upper pivot 25 mounted to the casing 10; a damper
spring 23 mounted in the damper cap 22, and configured to absorb
vibration from the outer tub 12; and a damper base 24 installed at
a lower opening of the damper cap 22, and configured to support the
connection rod 21 or the damper spring 23. Here, the upper pivot 25
for supporting an upper end of the connection rod 21 is installed
at the casing 10 or a suspension mounting portion 14 of the casing
10 or the body. And, a mounting hole 14a for inserting the upper
pivot 25 is formed at the suspension mounting portion 14.
[0011] According to a basic vibration reducing mechanism, vibration
occurring from the inner tub 13 is reduced by a viscous damping
force occurring as air is discharged through an air hole (not
shown) of the damper cap 22, and by a frictional damping force
occurring as the damper cap 22 and the damper base 24 come into
friction with each other. Here, excessive vibration or amplitude is
reduced by a viscous damping force.
[0012] Vibration occurring from the inner tub 13 or the outer tub
12 is transmitted to the casing 10 through the suspension 20. In
order to reduce vibration or noise transmitted to the casing 10 and
smoothly support the upper pivot 25, as shown in FIG. 3, a
lubricant 16 such as grease is deposited between the suspension
mounting portion 14 and a mounting surface for the upper pivot
25.
[0013] However, when the suspension 20 is severely moved due to
excessive vibration, the lubricant 16 disposed between the upper
pivot 25 and the suspension mounting portion 14 plane-contacting
each other is discharged out. Accordingly, the lubricant 16 does
not perform its function well.
[0014] Furthermore, since there is no medium material for absorbing
vibration or noise between the upper pivot 25 and the suspension
mounting portion 14, a contact area between the upper pivot 25 and
the suspension mounting portion 14 is increased. Accordingly, most
of vibration or noise occurring from the outer tub 12, etc. is
transmitted to the casing 11, thereby increasing entire noise or
vibration.
[0015] An air gap which allows a reciprocation of the washing
machine is formed between the damper cap 22 and the damper base 24.
If the washing machine 1 is used by approximately 1000 cycles, a
clearance of the air gap is increased to allow a large amount of
air to leak through the air gap. This causes a viscous damping
force to be greatly lowered, thereby not reducing excessive
vibration.
SUMMARY OF THE INVENTION
[0016] Therefore, it is a first object of the present invention to
provide a suspension apparatus for a washing machine capable of
reducing vibration or noise transmitted to a casing by decreasing a
contact area between a pivot and a suspension mounting portion of a
casing for mounting the pivot, by forming a contact area decreasing
portion on either the pivot or the suspension mounting portion, and
a washing machine having the same.
[0017] It is a second object of the present invention to provide a
suspension apparatus for a washing machine capable of allowing a
lubricant deposited onto a contact area decreasing portion to stay
for a long time without being discharged therefrom even when being
severely moved, by concavely forming the contact area decreasing
portion at either a pivot or a suspension mounting portion of a
casing for mounting the pivot, and a washing machine having the
same.
[0018] It is a third object of the present invention to provide a
suspension apparatus for a washing machine capable of having a
constant abrasion of a damper base in a circumferential direction
and capable of enhancing reliability, by using an extension spring
consecutively contacting the damper base in a circumferential
direction, and a washing machine having the same.
[0019] To achieve these and other advantages and in accordance with
the purpose of the present invention, as embodied and broadly
described herein, there is provided a suspension apparatus for a
washing machine, comprising: a pivot mounted to a casing; a damper
cap mounted to an outer tub installed in the casing; a connection
rod having the pivot and the damper cap at both ends thereof; and
an elastic means formed in the damper cap, wherein a contact area
decreasing portion for reducing a contact area on the surface of
the pivot is formed on the pivot.
[0020] Under this configuration, a contact area of the pivot to the
casing is reduced, and vibration or noise transmitted to the casing
due to a direct contact between the pivot and the casing is
reduced.
[0021] Here, the contact area decreasing portion is a dimple
concavely formed on the surface of the pivot, or a groove formed on
the surface of the pivot. That is, owing to a concaved dimple or
groove, a contact area of the pivot to the casing is reduced.
[0022] A lubricant may be deposited to the contact area decreasing
portion. Once a lubricant is deposited to the contact area
decreasing portion, i.e., the concaved dimple or groove, the
lubricant is not discharged out. Also, when the suspension
apparatus is severely moved at the time of excessive vibration, a
lubricating process can be stably performed, and a function for
preventing noise/vibration can be effectively performed.
[0023] A damper base sliding along an inner surface of the damper
cap, and configured to support one end of the connection rod is
further formed at one end of the damper cap. Below the damper base,
may be mounted an extension spring for uniformly maintaining an air
gap between the damper base and the damper cap, and thereby
increasing a viscous damping force by air leaked through the air
gap.
[0024] Here, the extension spring consecutively contacts a lower
side surface of the damper base. The reason is in order to maintain
a constant abrasion of the damper cap and the damper base in a
circumferential direction, to reduce a lowering of a viscous
damping force due to non-uniform increase of an air gap, and to
prolong a life-span of the suspension apparatus.
[0025] A base cap for reducing a leakage amount of air inside the
damper cap may be further mounted below the damper cap.
Accordingly, even if the air gap between the damper cap and the
damper base is non-uniformly increased, a lowering of a viscous
damping force can be prevented.
[0026] To achieve these and other advantages and in accordance with
the purpose of the present invention, as embodied and broadly
described herein, there is also provided a washing machine having a
suspension apparatus, the washing machine comprising a casing, an
outer tub installed in the casing, and a suspension apparatus
installed between the casing and the outer tub, wherein the
suspension apparatus comprises: a pivot mounted to the casing; a
damper cap mounted to the outer tub installed in the casing; a
connection rod having the pivot and the damper cap at both ends
thereof; and an elastic means formed in the damper cap, wherein a
contact area decreasing portion for reducing a contact area between
the pivot and the casing is formed on the surface of either the
casing, or the pivot.
[0027] The contact area decreasing portion may be implemented as a
concaved dimple or groove, and a lubricant may be deposited to the
contact area decreasing portion. Once a lubricant is deposited to
the contact area decreasing portion, the lubricant is not
discharged out. Also, when the suspension apparatus is severely
moved at the time of excessive vibration, a lubricating process can
be stably performed, and a function for preventing noise/vibration
can be effectively performed.
[0028] A base cap for reducing a leakage amount of air inside the
damper cap may be further mounted below the damper cap. An air hole
for a viscous damping may be formed at either the damper cap or the
base cap, or at both of them.
[0029] A damper base sliding along an inner surface of the damper
cap, and configured to support one end of the connection rod is
further formed at one end of the damper cap. Below the damper base,
may be mounted an extension spring for uniformly maintaining an air
gap between the damper base and the damper cap, and thereby
increasing a viscous damping force by air leaked through the air
gap.
[0030] Under this configuration, a lowering of a viscous damping
force due to air inside the damper cap can be reduced.
[0031] The foregoing and other objects, features, aspects and
advantages of the present invention will become more apparent from
the following detailed description of the present invention when
taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention and together with the description serve to explain
the principles of the invention.
[0033] In the drawings:
[0034] FIG. 1 is a schematic sectional view of a washing machine in
accordance with the related art;
[0035] FIG. 2 is a schematic sectional view of a suspension
apparatus for a washing machine in accordance with the related
art;
[0036] FIG. 3 is an enlarged sectional view of `A` of FIG. 2;
[0037] FIGS. 4A to 4C are views showing a pivot of a suspension
apparatus according to the present invention;
[0038] FIG. 5 is a sectional view showing a state that the pivot of
FIG. 4 is mounted to a washing machine;
[0039] FIG. 6 is a sectional view of a lower configuration of the
suspension apparatus of FIG. 4;
[0040] FIGS. 7A to 7C are views respectively showing an extension
spring of the suspension apparatus of FIG. 4;
[0041] FIG. 8 is a sectional view showing a modification example of
a lower configuration of the suspension apparatus of FIG. 6;
and
[0042] FIG. 9 is an experimental graph showing each noise occurring
from the conventional suspension apparatus and the suspension
apparatus of FIG. 4 according to a frequency.
DETAILED DESCRIPTION OF THE INVENTION
[0043] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings.
[0044] Hereinafter, the configuration and operation of a suspension
apparatus for a washing machine according to one embodiment of the
present invention will be explained in more detail with reference
to the attached drawings.
[0045] Explanation for well-known configurations or functions will
be omitted. And the same reference numerals will be given to the
same parts as those of the aforementioned configurations, and their
detailed explanation will be omitted.
[0046] FIGS. 4A to 4C are views showing an upper pivot of a
suspension apparatus according to the present invention, and FIG. 5
is a sectional view of the upper pivot of FIG. 4 showing a mounted
state to a washing machine.
[0047] Referring to FIG. 4A, an upper end of a connection rod 210
of a suspension apparatus 200 according to the present invention is
exposed to an upper surface of a pivot 270 by penetrating the pivot
270. The upper end of the connection rod 210 undergoes a caulking
process, or is implemented as an additional member such as nuts so
as not to be separated from the pivot 270.
[0048] When viewed from the top, the pivot 270 has an approximate
circle shape. A coupling hole 271 for the connection rod 210 is
formed at a central portion of the pivot 270. A connection rod
supporting portion 272 for stably supporting the connection rod 210
is extendingly formed at a part where the coupling hole 271 is
formed, in a downward direction along the connection rod 210.
[0049] A part where the connection rod supporting portion 272
starts to extend is extended in a circumferential direction,
thereby being integrally formed with a mounting portion 273 having
a similar shape to a top. Here, a lower surface of the mounting
portion 273 comes in contact with the casing 10 (refer to FIG. 1)
of the washing machine 10 (refer to FIG. 1) or the body, thereby
mounting the pivot 270.
[0050] A contact area decreasing portion 274 is formed on a lower
surface of the mounting portion 273. The contact area decreasing
portion 274 serves to decrease a contact area between a lower
surface of the mounting portion 273 and the surface of the casing
10.
[0051] The contact area decreasing portion 274 is concavely formed
on a lower surface of the mounting portion 273, and is preferably
implemented as a dimple or a groove on the surface of a golf
ball.
[0052] FIG. 4B is a bottom view of the pivot 270 having a plurality
of contact area decreasing portions 274 in the form of dimples, and
FIG. 4C is a bottom view of a pivot 270' having a plurality of
contact area decreasing portions 274' in the form of concaved
grooves.
[0053] Here, the contact area decreasing portions 274 and 274' may
be concavely formed on each lower surface of the mounting portions
273 and 273', and may be also protruding from each lower surface of
the mounting portions 273 and 273'.
[0054] Regardless of a concaved shape or a convex shape, the
contact area decreasing portions 274 and 274' may have any shape to
decrease a contact area between each surface of the mounting
portions 273 and 273' and the casing 10.
[0055] FIG. 5 is a view showing a state that the pivot 270 of the
suspension apparatus 200 is mounted to a suspension mounting
portion 140 of the casing. The suspension mounting portion 140 is a
part of the casing 10 (refer to FIG. 1) or the body. Preferably,
the suspension mounting portion 140 is respectively formed at four
corners of the washing machine 1. A mounting hole for inserting the
pivot 270 is formed at the suspension mounting portion 140.
[0056] A lubricant 160 such as grease is interposed between the
suspension mounting portion 140 and the pivot 270 mounted to the
mounting hole of the suspension mounting portion 140.
[0057] Preferably, a sufficient amount of the lubricant 160 is
deposited between the pivot 270 and the suspension mounting portion
140.
[0058] The lubricant 160 is filled in the contact area decreasing
portions 274 and 274', thereby performing a lubricating process so
as to decrease a friction between the suspension mounting portion
140 and the mounting portion 273 of the pivot 270.
[0059] The lubricant 160 may also perform a vibration absorbing
function or a vibration preventing function, which prevents or
reduces vibration or noise occurring along the connection rod 210
from being transmitted to the casing 10 or the suspension mounting
portion 140 via the pivot 270. More concretely, vibration or noise
transmitted to the casing 10 where the suspension mounting portion
140 is formed, or to the body has a lowered intensity via the
lubricant 160 deposited between the pivot 270 and the suspension
mounting portion 140, and then is transmitted to the casing 10,
etc. Accordingly, noise due to vibration of the case 10, etc. is
considerably reduced.
[0060] Furthermore, even if the suspension apparatus 200 is
severely moved due to vibration of outer tub 12 (refer to FIG. 1)
in an excessive vibration state such as an initial stage for
dehydration, the lubricant can stably stay at the contact area
decreasing portions 274 and 274', and the lubricant 160 deposited
between the pivot 270 and the suspension mounting portion 140 is
prevented from being discharged therefrom.
[0061] The contact area decreasing portions 274 and 274' may be
formed not only on the pivot 270 of the suspension 120, but also on
the suspension mounting portion 140 or the casing 10. That is, the
contact area decreasing portions 274 and 274' may be formed on the
surface of either the suspension mounting portion 140, or the
mounting portion 273 of the pivot 270.
[0062] Hereinafter, a lower part of the suspension apparatus, that
is, a part connected to the outer tub 12 will be explained in more
detail.
[0063] FIG. 6 is a sectional view of a lower configuration of the
suspension apparatus of FIG. 4, FIGS. 7A to 7C are views
respectively showing an extension spring of the suspension
apparatus of FIG. 4, and FIG. 8 is a sectional view showing a
modification example of a lower configuration of the suspension
apparatus of FIG. 6.
[0064] As shown in FIG. 6, the suspension apparatus 200 for a
washing machine according to the present invention comprises: a
connection rod 210; a damper cap 220 having one end of the
connection rod 210 penetratingly formed thereat; a damper spring
230 installed in the damper cap 220; a damper base 240 configured
to support one end of the connection rod 210 penetratingly
installed at the damper cap 220; extension springs 260 mounted to a
lower side of the damper base 240; and a base cap 250 mounted to a
lower opening of the damper cap 220.
[0065] An upper portion of the damper cap 220 is upwardly extending
like a bottle neck, and the upwardly extending portion encompasses
the connection rod 210.
[0066] The connection rod 210 is positioned inside the damper cap
220 via a through hole 222 formed at the upper portion of the
damper cap 220. One end of the through hole 222 is protruding to
inside of the damper cap 220, thereby constituting a connection rod
supporting portion 223 that encompasses and supports the connection
rod 210.
[0067] One end of the connection rod 210 is fixed to a connection
rod fixing portion 241 protruding from an upper surface of the
damper base 240 by a certain height. Preferably, the connection rod
fixing portion 241 is formed to have a certain height so as to
stably support the connection rod 210.
[0068] A plurality of protrusions 242 are formed on an outer
circumferential surface of the connection rod fixing portion 241.
The plurality of protrusions 242 are forcibly inserted into an
inner circumferential surface of the damper spring 230, thereby
stably supporting the damper spring 230.
[0069] A lower end of the damper spring 230 is supported by the
protrusions 242 on the surface of the connection rod fixing portion
241, and an upper end of the damper spring 230 is supported by a
spring supporting portion 224 formed on an inner surface of the
damper cap 220.
[0070] At an initial state, i.e., at a state that the washing
machine is not provided with washing water or laundry therein, the
damper spring 230 preferably maintains a compressed state, and the
damper base 240 for supporting the damper spring 230 is positioned
at an inner side of a lower end of the damper cap 220. The reason
is as follows. Once laundry or washing water is introduced into the
inner tub 13 (refer to FIG. 1), the damper spring 230 is extended
due to a weight of the laundry or washing water, and the damper
base 240 moves to a lower side of the damper cap 220. Here, if the
damper base 240 is positioned at the end of the damper cap 220,
laundry, etc. is introduced into the inner tub 13, and the damper
base 240 may be completely separated from the damper cap 220.
[0071] Here, the damper spring 230 is preferably a compression coil
spring, but is not limited thereto. As the damper spring 230, any
elastic means having an elastic restoration force and configured to
absorb or attenuate vibration may be used. For example, a rubber
member may be used to connect one end of the connection rod 210 and
the connection rod fixing portion 241 of the damper base 240. Also,
a rubber pillar (not shown) having a cavity therein may be used as
the damper spring 230. When the damper spring 230 is used as an
elastic means, one end of the connection rod 210 disposed in the
damper cap 220 is preferably disposed inside the damper spring
230.
[0072] An air hole 221 is formed at an upper portion of the damper
cap 220, through which a viscous damping process due to air inside
the damper cap 220 is performed. Between an inner surface of the
damper cap 220 and an outermost circumference of the damper base
240, a minute air gap (not shown) is formed. A frictional damping
process occurs through the air gap.
[0073] The base cap 250 may be mounted to a lower opening of the
damper cap 220. The base cap 250 is coupled to the damper cap 220
by a hook (not shown) formed at the damper cap 220 with receiving
the damper base 240 therein. In order to ensure a sealed state
inside the damper cap 220, the damper cap 220 and the base cap 250
may be coupled to each other by forming a screw thread at a
coupling portion therebetween.
[0074] The damper base 240 will be explained in more detail with
reference to FIG. 5.
[0075] The connection rod fixing portion 241 connected to one end
of the connection rod 210 is formed above the damper base 240, and
the plurality of protrusions 242 are provided on an outer
circumferential surface of the connection rod fixing portion 241. A
spring supporting portion 243 is integrally formed below the
connection rod fixing portion 241. Preferably, the spring
supporting portion 243 is formed in a wide disc shape so as to
sufficiently support the damper spring 230.
[0076] A skirt portion 244 having an area wider than that of the
spring supporting portion 243 is integrally formed below the spring
supporting portion 243. Here, the skirt portion 244 is in a thin
cylindrical shape having a predetermined height, and an air gap is
formed between an outer surface of the skirt portion 244 and an
inner surface of the damper cap 220.
[0077] Referring to FIG. 7A, a plurality of slits (not shown) are
formed at the skirt portion 244 in a height direction, and an
extension spring 260 is mounted to an inner surface of the skirt
portion 244. Here, in order to prevent the extension spring 260
from being separated from the skirt portion 244, a concaved groove
(not shown) or stopping jaws 245 are formed on an inner surface of
the skirt portion 244.
[0078] Since the extension spring 260 is mounted to the skirt
portion 244 with a diameter decreased than the original diameter,
it has an elastic restoration force to restore the original
diameter. Due to the elastic restoration force, the edge of the
damper base 240 is extended to an inner surface of the damper cap
220. That is, the skirt portion 244 is pushed to the damper cap 220
thus to be extended.
[0079] Here, the skirt portion 244 can have a large extension
degree by being provided with the plurality of slits in a height
direction thereof. The skirt portion 244 can be outwardly extended
even by the extension spring 260 having a small elastic restoration
force.
[0080] Either the stopping jaws 245 or the slits, or both the
stopping jaws 245 and the slits can be formed with consideration of
the size of the damper base 240, or an elastic force of the
extension spring 260, etc.
[0081] The extension spring 260 has to be provided with a
consecutive circumference.
[0082] When viewed from the front, the extension spring 260 is in a
ring shape having a consecutive circumference (refer to FIG. 7B),
whereas when viewed from the side, the extension spring 260 has
some parts overlapping each other in a longitudinal direction
(refer to FIG. 7C). That is, the extension spring 260 is wound so
that both ends thereof can overlap each other by a predetermined
length.
[0083] Here, curved portions 260a and 260b are formed at both ends
of the extension spring 260 toward the center of the extension
spring 260. The curved portions 260a and 260b are used to mount the
extension spring 260 to the damper base 240. When the curved
portions 260a and 260b are pressed at both sides, a diameter of one
side of the extension spring 260 is decreased to allow the
extension spring 260 to be easily mounted to the damper base 240.
Then, when the curved portions 260a and 260b are released, the
extension spring 260 is restored to the original state. At the same
time, the skirt portion 243 is outwardly extended.
[0084] As shown in FIG. 7A, the extension spring 260 consecutively
contacts lower side surfaces of the damper base 240, i.e., the
skirt portion 244, due to its consecutive circumference. That is,
all parts of the extension spring 260 come in contact with the
skirt portion 244. Accordingly, an air gap between the damper cap
220 and the damper base 240 is uniformly maintained in a
circumferential direction of the extension spring 260, thereby
preventing non-uniform clearance of the air gap.
[0085] As the extension spring 260 having a consecutive
circumference is used, the skirt portion 244 of the damper base 240
is prevented from being flatly abraded even when coming into
friction with an inner surface of the damper cap 220.
[0086] The suspension apparatus 200' of FIG. 8 is different from
the suspension apparatus 200 of FIG. 6 in that an air hole 251 is
formed at a base cap 250'.
[0087] According to the suspension apparatus 200 of FIG. 6, the
base cap 250 is mounted to a lower side of the damper cap 220, but
an air hole is not formed at the base cap 250. This allows air
leakage through the air gap to be prevented, but causes air inside
the damper cap 220 to have a difficulty in being discharged out,
which can not reduce excessive vibration. In order to solve this
problem, the air hole 251 may be formed at the base cap 250'.
[0088] The air hole 251 of the base cap 250' is formed
approximately at a lower surface of the suspension apparatus 200'.
Accordingly, even if a lubricant such as grease deposited on the
damper cap 220 flows down, the air hole 251 is not blocked.
[0089] When the air hole 251 is formed at the base cap 250', it is
preferable not to form the air hole 221 blocked by a lubricant at
the damper cap 220. However, when a sufficient viscous damping
force can not be obtained from the air hole 251 of the base cap
250', it is effective to form the air hole 221 at the damper cap
220. In this case, in order to prevent the air hole 221 of the
damper cap 220 from being blocked by a lubricant such as grease,
the air hole 221 is formed at an upper side.
[0090] In order to reduce excessive vibration of the washing
machine by using a viscous damping force occurring from air
leakage, either the air hole 221 of the damper cap 220 or the air
hole 251 of the base cap 250', or both of them may be formed. This
selection has to be performed in the aspect of vibration with
consideration of a capacity of the washing machine, a rotation
speed of the inner tube at the time of a dehydration process,
etc.
[0091] By using each of the suspension apparatuses 200 and 200',
the air gap between the damper cap 220 and each of the dampers
bases 250 and 250' can be constantly maintained. This causes a
viscous damping force by air leaked through the air gap to be
increased.
[0092] FIG. 9 is an experimental graph showing each noise according
to a frequency, the noise occurring from the conventional
suspension apparatus and the suspension apparatus of FIG. 4.
[0093] Referring to FIG. 9, a horizontal axis of the graph denotes
a frequency (Hz), and a vertical axis of the graph shows noise (dB)
transmitted to the suspension mounting portion 140 or the casing
10.
[0094] When comparing each noise occurring at a middle frequency
(`B` of FIG. 9), noise occurring from the suspension apparatuses
200 and 200' having the contact area decreasing portions 274 and
274' according to the present invention is considerably less than
noise occurring from the conventional suspension apparatus.
[0095] So far, the present applicant explained about the suspension
apparatus applied to a washing machine, but the suspension
apparatus may also be applied to various fields such as a washing
machine compatible with a drier, a dryer, or a combined washing
system.
[0096] The foregoing embodiments and advantages are merely
exemplary and are not to be construed as limiting the present
invention. The present teachings can be readily applied to other
types of apparatuses. This description is intended to be
illustrative, and not to limit the scope of the claims. Many
alternatives, modifications, and variations will be apparent to
those skilled in the art. The features, structures, methods, and
other characteristics of the exemplary embodiments described herein
may be combined in various ways to obtain additional and/or
alternative exemplary embodiments.
[0097] As the present features may be embodied in several forms
without departing from the characteristics thereof, it should also
be understood that the above-described embodiments are not limited
by any of the details of the foregoing description, unless
otherwise specified, but rather should be construed broadly within
its scope as defined in the appended claims, and therefore all
changes and modifications that fall within the metes and bounds of
the claims, or equivalents of such metes and bounds are therefore
intended to be embraced by the appended claims.
* * * * *