Power system of clothes washing machine

A clothes washing machine includes a water tub, a spin basket, and a clothes agitator. A vertical dehydrating shaft is fixed to the spin basket, and a laundering shaft extends coaxially within the dehydrating shaft. Upper and lower ends of the laundering shaft are connected to the agitator and a motor respectively, whereby rotation of the motor is always transmitted to the agitator. In order to selectively connect the dehydrating shaft to the laundering shaft (e.g., during a spin-drying operation), a connecting gear is mounted on the dehydrating shaft for rotation therewith and for vertical movement relative thereto. A power-driven actuator is provided for selectively moving the connecting gear up or down. When the connecting gear moves down, lower teeth thereon become operably connected to the motor so that the dehydrating shaft and laundering shaft rotate together. During a washing or rinsing operation, the connecting gear is moved up, whereby upper teeth thereon become connected to a fixed element, whereby the dehydrating shaft is fixed against rotation.

BACKGROUND OF THE INVENTION 
(1) Field of the Invention 
The present invention relates to a power system of a washing machine and, 
more particularly, to a power system of a washing machine which can 
suppress a rotation of a rotating drum during a washing operation and 
rotate the rotating drum at a high speed during a dehydrating or spin 
drying operation. 
(2) Description of the Related Art 
Generally, a washing machine includes a main body defining an outer 
configuration thereof, a water reserving drum or water tub installed 
within the body, and rotating drum or spin basket and agitator blade 
mounted within the water reserving drum. A power system for driving the 
rotating drum and blade is mounted under the water reserving drum. 
The power system conventionally comprises a motor, a power transmission 
system, and a belt for connecting the motor to the power transmission 
system. This will be described hereinbelow with reference to FIG. 6. 
As shown in drawing, a conventional power transmission system 10 has a 
hollow dehydrating shaft 11 and a laundering shaft 12 inserted into the 
hollow portion of the hollow dehydrating shaft 11. The laundering shaft 12 
is divided into upper and lower portions, with a planetary gear unit 13 
being disposed therebetween. The planetary gear unit 13 controls a 
rotating speed. A brake band 14 and a brake lever 15 are disposed beside 
the dehydrating shaft 11 so as to brake the rotation of the dehydrating 
shaft 11. A one-way bearing 16, for suppressing an idling rotation of a 
rotating drum 21 by cooperating with the brake band 14 and allowing the 
dehydrating shaft 11 to rotate in only one direction, is mounted on an 
outer circumference of the dehydrating shaft 11. In addition, a clutch 
spring 17 and a clutch lever 18 for transmitting/interrupting power from 
the motor to both the dehydrating shaft 11 and the laundering shaft 12 are 
mounted under the one-way bearing 16. A pulley 19 on which a belt (not 
shown) is engaged is mounted on a lower end of the laundering shaft 12. 
In this conventional power transmission system 10, torque of the motor is 
selectively transmitted to the rotating blade 22 or the rotating drum 21 
through the clutch spring 17, thereby performing the washing and 
dehydrating (spin drying) operations. To achieve this, it is necessary 
that the clutch spring 17 has high tensile strength to enable the 
transmission or interruption of torque from the motor to the dehydrating 
shaft 11 and the laundering shaft 12, both of which are rotated at a high 
speed. However, the manufacturing process for such a spring having high 
tensile strength is complicated, and, as a result, manufacturing costs are 
increased. 
In addition, the brake band 14 for preventing the rotating drum 21 from 
idling during the washing operation is, when it brakes the rotating drum 
21 in one direction, subjected to high force generated when the rotating 
drum 21 is urged to rotate by a water current within the water reserving 
drum. The above described one-way bearing 16 must be used as a result, 
making the structure complicated and increasing manufacturing costs. 
Finally, an unpleasant noise is generated during the braking operation of 
the brake band. 
As described above, the conventional power system of a washing machine is 
complicated with regard to the arrangement of parts for performing the 
washing, dehydrating and braking operations, making it difficult to 
manufacture the same and increasing manufacturing costs. In addition, 
because of the large number of parts needed for this complicated 
arrangement, much space is required which, in turn, acts to increase the 
overall size of the washer. 
SUMMARY OF THE INVENTION 
Therefore, the present invention is made in an effort to solve the above 
described problems. 
It is an object of the present invention to provide a washing machine 
having a power system which is easy to manufacture by integrally 
connecting the power transmission system to a drive motor. 
It is another object of the present invention to provide a washing machine 
which can minimize the noise generated during operation. 
To achieve the above objects, the present invention provides a washing 
machine, comprising a water reserving drum for reserving water therein, a 
rotating drum mounted inside the water reserving drum, a rotating blade 
assembly mounted on an inner bottom surface of the rotating drum, a 
reversible motor mounted under the water reserving drum, a hollow 
dehydrating shaft having an upper end coupled to the rotating drum and a 
lower end extending outside the water reserving drum, and a laundering 
shaft inserted into the hollow dehydrating shaft such that the laundering 
shaft extends out of the upper and lower ends of the hollow dehydrating 
shaft, the laundering shaft having an upper end coupled to the rotating 
blade assembly and a lower end coupled to the motor, a coupling member 
coupled on an outer circumference of the lower end of the laundering shaft 
so as to rotate therewith, a connecting member mounted on the dehydrating 
shaft to be ascendable/descendible along a longitudinal axis of the 
dehydrating shaft, the connecting member allowing, when ascended, the 
laundering shaft to rotate by itself and, when descended, the laundering 
and dehydrating shafts to rotate by coupling to the coupling member, and 
means for raising and lowering the connecting member.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
Reference will now be made in detail to the present preferred embodiments 
of the invention, examples of which are illustrated in the accompanying 
drawings. Wherever possible, the same reference numbers will be used 
throughout the drawings to refer to the same or like parts. 
Referring first to FIG. 1, the inventive washing machine comprises a main 
body 50 defining an outer configuration thereof and a water reserving drum 
or water tub 51 installed inside the main body 50 which holds water. A 
rotating drum or spin basket 52, inside of which laundry is washed, is 
provided inside the water reserving drum 51. Installed above a bottom 
surface of the rotating drum 52 is a rotating agitator blade assembly 53 
which rotates in forward and reverse directions so as to generate water 
currents. 
A power system 60, for driving the rotating blade assembly 53 and the 
rotating drum 52, is installed under the water reserving drum 51. Here, 
the power system 60 comprises a reversible motor 90 and a power 
transmission system 70, which transmits a rotating force of the reversible 
motor 90 to the rotating blade assembly 53 or the rotating reservoir 52. 
In addition, a drain hose 54 is mounted on the right side (in the drawing) 
of the power system 60, the drain hose 54 draining the water in the water 
reserving drum 51 out of the main body 50. A drain valve 55 for 
opening/closing the drain hose 54 is mounted on the drain hose 54. A drain 
motor (not shown) which controls the operation of the drain valve 55 and 
the power transmission system 70, is mounted between the drain valve 55 
and the power transmission system 70. 
The power transmission system 70 of the power system 60 is coupled at its 
upper portion to the rotating drum 52, and, as shown in FIG. 2, is 
provided at its lower portion with a hollow dehydrating shaft 72 which is 
passing through a bottom surface of the water reserving drum 51. There is 
further provided a cylindrical supporting plate 73 which is coupled on an 
inner bottom surface of the water reserving drum 51 so that the 
dehydrating shaft 72 can be supportably coupled thereon. Here, a bearing 
74 is disposed between the supporting plate 73 and the dehydrating shaft 
72 so that the dehydrating shaft 72 coupled to the supporting plate 73 can 
freely rotate. 
Inserted into the dehydrating shaft 72 is a laundering shaft 71, an upper 
end of which is coupled to the rotating blade assembly 53 and a lower end 
of which is coupled to a rotor 92 of the reversible motor 90 (see FIG. 3). 
Both ends of the laundering shaft 71 are serrated to allow for the 
coupling to the rotating blade assembly 53 and the reversible motor 90. 
Inserted around the dehydrating shaft 72 is a ring-shaped connecting gear 
77 which can ascend and descend along the dehydrating shaft 72. After the 
connecting gear 77 descends along the dehydrating shaft 72, the 
dehydrating shaft 72 rotates together with the laundering shaft 71, and 
after the connecting gear ascends, the laundering shaft rotates by itself. 
That is, a coupling gear 81 which is designed to integrally rotate with the 
reversible motor 90 is integrally mounted on a lower end of the laundering 
shaft 71 so that when the connecting gear 77 descends it can mesh with the 
coupling gear 81. 
The connecting gear 77 is provided at its inner lower circumference with 
inner teeth 77a, and at its outer upper circumference with outer teeth 
77b. A plurality of projections 77c are formed on an upper portion of the 
inner teeth 77a. The projections 77c are designed to be inserted into 
corresponding coupling grooves 72a, which extend along a portion of the 
dehydrating shaft 72 where the connecting gear 77 is coupled, so as to 
allow the connecting gear 77 to slide upward and downward along the 
coupling grooves 72a. 
In addition, the coupling gear 81 is provided on its outer upper portion 
with outer teeth 81a which are designed to mesh with the inner teeth 77a 
of the connecting gear 77 when the same descends. 
Mounted on an under surface of the water reserving drum 51 is a fixing 
plate 75. The fixing plate 75 is provided with inner teeth 75a which, 
after the connecting gear 77 ascends, mesh with the outer teeth 77b of the 
connecting gear 77 so as to restrict the rotation of the dehydrating shaft 
72. 
For the above operation, the connecting gear 77 is raised and lowered along 
the grooves 72a of the dehydrating shaft 72 by ascending/descending means 
which will be described more in detail hereinafter. 
The ascending/descending means comprises an ascending/descending guide 
member 76 which is coupled to the fixing plate 75 by fastener means such 
as bolts or screws (not shown). The guide member 76 is comprised of two 
pieces separated symmetrically. A semi-circular ascending/descending guide 
plate 76b extends from each proximal end of the plates. An inclined 
ascending/descending guide slit 76a which has an opened lower end is 
formed on the ascending/descending guide plate 76b. 
The ascending/descending means further comprises an ascending/descending 
ring 79 on which ascending/descending projections 79a are formed. The 
ascending/descending ring 79 is engaged with a stepped portion of the 
connecting gear 77. A bearing 78 is interposed between the connecting gear 
77 and the ascending/descending ring 79. The bearing 78 prevents rotating 
force from being transmitted to the ascending/descending ring 79 even when 
the connecting gear 77 rotates. The bearing 78 is designed to be fixed by 
a plurality of fixing steps 79b. The projections 79a are respectively 
formed on diametrically opposite sides of the ascending/descending ring 
79. 
As described above, the ascending/descending ring 79 is designed to guide 
the ascending/descending operation of the connecting gear 77 while 
ascending and descending along the ascending/descending guide slits 76a. 
For this operation, a ring-shaped ascending/descending gear 80 is 
connected to free ends of the ascending/descending projections 79a. 
The ascending/descending gear 80 is provided with outer teeth 80a at an 
outer circumference thereof, and is provided on its inner circumference 
with circumferentially opposed slots 80b into which the projections 79a 
are inserted. 
In addition, the outer teeth 80a of the ascending/descending gear 80 mesh 
with a rotating gear 82 for rotating the ascending/descending gear 80. A 
connecting bar 84 is articulated on the rotating gear 82 by a connecting 
pin 83. Rotating force of a drain motor (not shown) is transmitted to the 
connecting bar 84, thereby driving the rotating gear 82. 
As described above, the ring-shaped ascending/descending gear 80, the 
ascending/descending ring 79, and the connecting gear 77 are disposed in 
this order, thereby raising and lowering the connecting gear 77 when a 
driving force of the rotating gear 82 is applied. 
As shown in FIG. 3, the driving motor of the power system 60 is a brushless 
DC motor comprised of a rotor 92 and a stator 91 disposed inside the rotor 
92. The coupling gear 81 engaged with the laundering shaft 71 of the power 
transmission system 70 is coupled on a central portion of the rotor 92. 
Magnets 93 are mounted along an inner circumference of the rotor 92. The 
stator 91 is comprised of a core 94 facing the magnets 93 and a coil 95 
wound around the core 94 so that the rotor 92 is driven by electromagnetic 
force generated between the core 95 of the stator 91 and the magnet 93 of 
the rotor 92 by electric current applied to the coil 95. 
The operation of the above described power system 60 of the washing machine 
according to the present invention will be described hereinafter. 
A washing operation will be first described with reference to FIG. 3. The 
rotating gear 82 is rotated by the drain motor (not shown) which is driven 
by initial input current. By the rotation of the rotating gear 82, the 
ascending/descending gear 80 rotates, making the ascending/descending 
projections 79a rotate. The projections 79a ascend along the guide slits 
76a of the guide member 76 such that the ring 79 ascends. As a result, the 
connecting gear 77 ascends along the projections 72a of the dehydrating 
shaft 72 without rotating so that the outer teeth 77b of the connecting 
gear 77 become fixed by meshing with the inner teeth 75a of the fixing 
plate 75. 
In the above state, the laundry is placed in the rotating drum 52 and the 
water is fed to the water reserving drum 51, whereupon electric current is 
applied to the motor 90, so that the rotor 92 of the motor 90 rotates in 
the forward and reverse directions. Here, the laundering shaft 71 and the 
coupling gear 81 rotate with the rotation of the motor 90, thereby 
rotating the rotating blade assembly 53 coupled to the laundering shaft 71 
and performing the washing/rinsing operation. 
When the washing/rinsing operation is finished, the water reserved within 
the water reserving drum 51 is drained by the opening of the drain valve 
55 by the drain motor (not shown). 
After the water is completely drained, the dehydrating operation is 
performed in a state where the drain valve 55 is opened. The operation of 
the power system 60 during the dehydrating stroke will be described 
hereinafter with reference to FIG. 4. 
When the drain valve 55 is opened by the drain motor, the power 
transmission system 70 changes to a dehydrating driving state. That is, 
when the drain motor is operated, the drain valve 55 is opened, and at the 
same time, the rotating gear 82 rotates the ascending/descending gear 80. 
By the rotation of the ascending/descending gear 80, the projections 79a 
descend along the ascending/descending guide slits 76a of the 
ascending/descending guide assembly 76, thereby lowering the 
ascending/descending ring 79. As a result, the connecting gear 77 descends 
along the grooves 72a of the dehydrating shaft 72. The inner teeth 77a of 
the descended connecting gear 77 mesh with the outer teeth 81a of the 
coupling gear 81. In this state, when power is applied to the driving 
motor 90 so as to rotate the rotor 92 at a high speed, the laundering 
shaft 71 and the connecting gear 77 meshing with the coupling gear 81 also 
rotate at a high speed, thereby rotating the dehydrating shaft 72 at a 
high speed. 
By this operation, the rotating blade assembly 53 and the rotating drum 52 
rotate at a high speed such that the water retained in the laundry is 
squeezed out by the centrifugal force and drained through the drain hose 
54. 
When the motor stops, electrical power is applied to the motor such that a 
reversed magnetic flux can be generated in the coil 95 and, thus, a 
reversed electromagnetic force can be generated in the rotor 93. 
Therefore, the motor generates a reverse rotational force such that the 
rotating speed of the rotor 92 is rapidly reduced and consequently 
stopped. The operation is controlled by a control portion of the washing 
machine. 
Referring to FIG. 5, there is shown a sectional view of a power system 
according to a second embodiment of the present invention. 
As shown in the drawing, a laundering shaft 101 is inserted in a hollow 
shaft of a hollow dehydrating shaft 100. A coupling gear 102 is integrally 
mounted on a lower end of the laundering shaft 101. A fixing gear 103 is 
mounted on a lower surface of a water reserving drum or tub 111. A 
vertically movable connecting gear having upper and lower teeth 104a and 
104b divided by a stepped portion is disposed between the fixing gear 103 
and the coupling gear 102. The lower teeth 104b of the connecting gear 104 
mesh with the coupling gear after descending, and mesh with the fixing 
gear 103 after ascending. An ascending/descending ring 105 is coupled on 
the stepped portion of the connecting gear 104 by means of bearing 106 
interposed between the ascending/descending ring 105 and the connecting 
gear 104. The ascending/descending ring 105 is provided with two 
ascending/descending projections 105a which extend into guide slots 107a 
formed on a cylindrical guide member 107. The projections 105a extending 
into the slots 107a are designed to be moved downward in response to the 
application of an external force. A spring 108 is disposed between the 
upper end of each of the projections 105a and the lower end of the water 
reserving drum 11, thereby raising the connecting gear 104 by elastic 
force of the springs 108 when the outer force is released and making the 
connecting gear 104 mesh with the fixing gear 103. 
The connecting gear 104 is provided with a projection formed on an inner 
circumference and inserted into a groove 100a formed on an outer 
circumference of the dehydrating shaft 100. A bearing 110 is disposed 
between the dehydrating shaft 100 and the water reserving drum 11. 
In the above described second embodiment, the operations are performed as 
follows. 
For the dehydrating operation, when an external force is applied to the 
ascending/descending projections 105a, the connecting gear 104 moves 
downward and is engaged with the coupling gear 102, thereby causing the 
dehydrating and laundering shafts 100 and 101 to be rotated together. 
For the washing and rinsing, when the external force being applied to the 
ascending/descending projections 105 is released, the connecting gear 104 
ascends by the biasing force of the springs 108 and is engaged with the 
fixing gear 103 such that the dehydrating shaft 100 does not rotate but 
only the laundering shaft 101 rotates. 
While the invention has been described in connection with what is presently 
considered to be most practical and preferred embodiments, it is to be 
understood that the invention is not limited to the disclosed embodiments, 
but, on the contrary, it is intended to cover various modifications and 
equivalent arrangements included within the spirit and scope of appended 
claims.