Washing machine with structure for absorbing vibration of driving part

A washing machine with a vibration-absorbing structure for preventing the transfer of the vibration of the driving part is disclosed. The washing machine includes a rotor housing 50 in which a rotor is installed and which is rotatably moved, a driving shaft 20, 31, 33 for rotating a washing tub or a pulsator using a rotational force transferred from the rotor housing, a power transferring member 120 for transferring the rotational force of the rotor housing to the driving shaft, a rotor bushing 110 coupled to the rotor housing and through which the driving shaft penetrates to be slidingly moved, and at least one vibration-absorbing member 140, 150 installed on a path where a power is transferred from the rotor housing to the driving shaft, for absorbing vibration of the rotor housing.

This application claims the benefit of the Korean Application No. P2002-26458 filed on May 14, 2002, which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a washing machine, and more particularly, to a washing machine with a vibration-preventing structure for preventing the transfer of the vibration of the driving part to other part, thereby minimizing occurrence of vibration and noise.

2. Discussion of the Related Art

Generally, washing machine is an apparatus for washing laundry using frictional action of wash water, emulsification action of detergent and so forth. The wash procedure of the washing machine generally includes cycles of wash, rinse and dehydration.

In these washing machines, an outer tub containing wash water is fixedly installed inside a cabinet appearance of a washing machine, a washing tub for receiving the laundry is rotatably installed inside the outer tub, and a driving part for rotating the washing tub is installed below the outer tub.

Hereinafter, the structure of the driving part is described with reference toFIGS. 1 and 2.

FIG. 1is a sectional view of a driving part of a conventional washing machine, andFIG. 2is a sectional vie taken along the line I-I ofFIG. 1.

As shown inFIG. 1, a tub base2for supporting an outer tub1is installed at the lower portion of the outer tub1, and a bearing housing10is installed at the lower portion of the tub base2.

A stator3is installed at the lower portion of the bearing housing10, and a rotor5is rotatably installed outside the stator3. The rotor5is fixed to a rotor housing50. The rotor5is maintained spaced apart from the stator3at a constant interval, e.g., approximately 0.5 mm. In other words, the driving part shown inFIG. 1is an outer rotor type induction motor.

A hollow washing tub shaft20is rotatably installed inside the bearing housing10. Inside the washing tub shaft20is installed a decelerator40. An upper pulsator shaft33is connected to an upper portion of the decelerator40and a lower pulsator shaft31is connected to a lower portion of the decelerator40. At this time, the upper end of the washing tub shaft20is coupled to the washing tub (not shown), and the upper end of the upper pulsator shaft33is coupled to the pulsator (not shown).

A rotor bushing60is coupled to the core of the rotor housing50, and the lower end of the lower pulsator shaft31penetrates the rotor bushing60and is coupled thereto. The rotor bushing60is fixed to the rotor housing50by a plurality of coupling bolts65.

In order to transfer the rotational force of the lower pulsator shaft31to the washing tub shaft20, a coupling70is installed at the outer circumference of the washing tub shaft20and the outer circumference of the rotor bushing60. According to the location of the coupling70, the washing tub shaft20is selectively coupled to the rotor bushing60, and during their coupling, the rotational force of the lower pulsator shaft31is transferred to the washing tub shaft20.

As shown inFIG. 2, a coupling part61having a polygonal section is formed at the inner circumference of the rotor bushing60. The coupling part61is coupled to the outer circumference of the lower pulsator shaft31to transfer the rotational force of the rotor housing50to the lower pulsator shaft31. Also, a serration part63is formed at the outer circumference of the rotor bushing60. Through the serration part63, the coupling70ascends and descends, and the lower pulsator shaft31and the washing tub shaft20are coupled or separated depending on the location of the coupling70.

Meanwhile, as shown inFIG. 1, between the bearing housing10and the washing tub shaft20, and between the washing tub shaft20and the pulsator shaft31,33are installed a plurality of bearings11,13.

However, the driving part of the conventional washing machine may cause the following problems. In other words, since the rotor5is a rotational body, it always generates some vibration. Then, since the rotor housing50is directly coupled to the pulsator shaft31,33or the washing tub shaft20through the rotor bushing60, the vibration of the rotor5is transferred without any filtering. In this case, the vibration of the rotor5is transferred to the washing tub or the outer tub1, so that a considerable noise is caused.

In particular, the rotor5does not rotate at a constant revolution per minute (RPM) but is driven while varying the RPM within a certain range. Owing to the variation of the RPM, there occurs a ripple phenomenon in which the pulsator shaft31,33or the washing tub shaft20vibrates. For instance, if the rotor5is set to rotate at an 850 rpm, it rotates in real in a range of 840-860 rpm. At this time, the ripple phenomenon is one vibration source, which is directly transferred to the washing tub or the outer tub1to cause a regular noise during its operation.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a washing machine with a structure for absorbing vibration of a driving part that substantially obviates one or more problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a washing machine with a vibration-preventive structure for preventing the transfer of the vibration of the driving part to other part, thereby minimizing occurrence of vibration and noise.

To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a washing machine includes: a rotor housing in which a rotor is installed and which is rotatably moved; a driving shaft for rotating a washing tub or a pulsator using a rotational force transferred from the rotor housing; a power transferring member for transferring the rotational force of the rotor housing to the driving shaft; a rotor bushing coupled to the rotor housing and through which the driving shaft penetrates to be slidingly moved; and at least one vibration-absorbing member installed on a path where a power is transferred from the rotor housing to the driving shaft, for absorbing vibration of the rotor housing.

In an aspect, the power transferring member is a bracket which is coupled to the rotor housing and at the same time which the driving shaft penetrates to be coupled to.

At this time, the vibration-absorbing member is installed between the rotor housing and the bracket. The vibration-absorbing member is fixed by a coupling member for fixing the rotor bushing and the bracket to the rotor housing.

In an aspect, the washing machine of the present invention further includes a power breaking member coupled to the driving shaft, for selectively transferring the rotational force of the rotational shaft to the washing tub.

At this time, the vibration-absorbing member is installed between the rotor bushing and the power breaking member.

Thus, according to the present invention, the driving shaft is not directly coupled to the rotor bushing like the conventional art but only penetrates the rotor bushing to be coupled to the rotor housing through the bracket. At this time, since the vibration-absorbing member is installed between the bracket and the rotor housing, the vibration of the rotor is absorbed by the vibration-absorbing member before it is transferred to the driving shaft. Accordingly, it is prevented that the washing tub or outer tub vibrates through the driving shaft, thereby preventing occurrence of noise.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 3is a sectional view of a driving part of a washing machine according to a preferred embodiment of the present invention, and shows a state of wash cycle,FIG. 4is a disassembled perspective view of main elements of the driving part ofFIG. 3, andFIG. 5illustrates is a sectional view of a driving part of a washing machine according to a preferred embodiment of the present invention, and shows a state of dehydration cycle.

First, as shown inFIG. 3, a tub base2for supporting an outer tub1is installed at the lower portion of the outer tub1, and a bearing housing10is installed at the lower portion of the tub base2.

A stator3is installed at the lower portion of the bearing housing10, and a rotor5is rotatably installed outside the stator3. The rotor5is fixed to a rotor housing50. Accordingly, the rotor housing50is rotatable along with the rotor5. The rotor5is maintained spaced apart from the stator3at a constant interval, e.g., approximately 0.5 mm.

A driving shaft penetrates the interior of the bearing housing10. The driving shaft includes a hollow washing tub shaft20and a pulsator shaft31,33rotatably installed inside the washing tub shaft20. At this time, two, upper and lower bearings11are installed between the bearing housing10and the hydration shaft20, and a plurality of bearings are also installed between the washing tub shaft20and the pulsator shaft31,33. A washing tub5is coupled to the upper end of the washing tub shaft20, and a pulsator is coupled to the upper end of the pulsator shaft33.

Inside the washing tub shaft20is installed a decelerator having a proper deceleration ratio. At this time, the pulsator shaft is divided into the upper pulsator shaft33and the lower pulsator shaft31round the decelerator40. The decelerator40includes a line gear41, a plurality of epicyclic gears42and a rim gear43formed at the inner wall of the washing tub shaft20. The decelerator properly reduces revolution per minute (RPM) and transfers the reduced RPM to the upper pulsator shaft33.

A rotor bushing110is installed at the upper portion of the rotational core of the rotor housing50, and a bracket120is installed at the lower portion of the rotor bushing110. The lower pulsator shaft31penetrates the cores of the rotor bushing110and the bracket120. At this time, the lower pulsator shaft31penetrates the rotor bushing110, but they are not coupled with each other. Accordingly, the lower pulsator shaft is only slidingly moved with respect to the rotor bushing110. Also, the bracket120functions as a power transferring member for transferring the rotational force of the rotor housing50to the lower pulsator shaft31. For this purpose, the bracket is coupled to the rotor housing50and at the same time is also coupled to the lower pulsator shaft31. Also, the rotor bushing110and the bracket120are fixed to the rotor housing50by a plurality of coupling members160. Here, it should be noted that the bracket120and the rotor bushing110are conventionally made in a single member, but they are made in two separatable members in the present invention. Such a separate structure is to minimize a transfer of the vibration, as will be described later.

Over the rotor bushing110is installed a power breaking member130. The power breaking member130is a member for selectively transferring the rotational force of the lower pulsator shaft31to the washing tub shaft. For this purpose, the lower pulsator shaft31penetrates the core of the power breaking member130, and the power breaking member130and the lower pulsator shaft31are coupled to each other. Here, it should be noted that the power breaking member130and the lower pulsator shaft31are conventionally made in a single member, but they are made in two separatable members in the present invention. Such a separate structure is to minimize a transfer of the vibration, as will be described later.

A coupling70is installed at an outer circumference of the washing tub shaft20. The coupling70selectively constrains the washing tub shaft20to the power breaking member130while ascending and descending along the outer circumference of the power breaking member130. For this purpose, a serration part21is formed at an outer circumference of the washing tub shaft20, and a serration part is also installed at an inner circumference of the coupling70. At this time, a protruded part71is formed in the coupling70and an insertion groove15is formed in the bearing housing10. In other words, when the coupling70ascends, the protruded part71is inserted into the insertion groove15and fixed to.

Meanwhile, in order to prevent the vibration generated from the rotor5from being transferred to the washing tub or the outer tub1, at least one vibration-absorbing member140,150is installed on a path where a power is transferred from the rotor housing50to the pulsator shaft31,33or the washing tub shaft20. At this time, the vibration-absorbing member includes a first vibration-absorbing member140installed between the rotor housing50and the bracket120, and a second vibration-absorbing member150installed between the rotor bushing110and the power breaking member130. The first vibration-absorbing member140absorbs the vibration of the rotor housing50, thereby preventing the vibration from being transferred to the lower pulsator shaft31. The vibration-absorbing member150absorbs the vibration of the rotor bushing110rotating along with the rotor housing50, thereby preventing the vibration from being transferred to the washing tub shaft20.

Hereinafter, coupling relations of elements including the lower pulsator shaft31and the bracket are concretely described.

As shown inFIG. 4, the lower pulsator shaft31is provided with a first coupling part31ahaving a polygonal section, approximately hexagon section, and a second coupling part31bextended from the lower end of the first coupling part31aand having a screw thread formed at the surface thereof. The first coupling part31asequentially penetrates the power breaking member130, the second vibration-absorbing member150, the rotor bushing110and the bracket120. The lower pulsator shaft31is fixed to the bracket120by coupling the second coupling part31bwith a nut35.

The power breaking member130is a ring-shaped member that is the same in outer diameter as the washing tub shaft20, and has a coupling hole formed at the core thereof. The power breaking member130is coupled to the lower pulsator shaft31through the coupling hole131. For this purpose, the coupling hole131has a polygonal face corresponding to the first coupling part31aof the lower pulsator shaft31. At this time, it may be allowed to form a serration part engaged with the first coupling part31aof the lower pulsator shaft31and the coupling hole131of the power breaking member130, respectively. And, a serration part133is formed at the outer circumference of the power breaking member130. The serration part133of the power breaking member130is selectively coupled to the serration part formed at the inner circumference of the coupling70. In other words, the coupling70ascends and descends along the serration part21of the washing tub shaft20and the serration part133of the power breaking member130.

The second vibration-absorbing member150is a ring-shaped sheet, and has a penetration hole151formed at the core thereof and through which the first coupling part31aof the lower pulsator shaft31penetrates.

The rotor bushing110has a penetration hole111formed at the core thereof. The first coupling part31aof the lower pulsator shaft31penetrates the penetration hole111of the rotor bushing110. However, the first coupling part31ais not coupled to the penetration hole111. Accordingly, the lower pulsator shaft31and the rotor bushing110perform only a sliding motion, and do not influence the rotation of the counterpart. And, a circular mounting groove113is formed at the lower surface of the rotor bushing110. (refer toFIG. 3)

The bracket120has a coupling hole121formed at the core thereof. The lower pulsator shaft31penetrates the coupling hole121to be coupled to the bracket120. For this purpose, the coupling hole121of the bracket120has a polygonal face corresponding to the first coupling part31aof the lower pulsator shaft31. At this time, it may be allowed to form a serration part engaged with the first coupling part31aof the lower pulsator shaft31and the coupling hole121of the bracket120, respectively. The bracket120has a circular protruded mounting part123formed at the core thereof. The mounting part123is inserted into the mounting groove113of the rotor bushing110. At this time, the mounting part123maintains a status that is not in contact with the mounting groove113.

As aforementioned, the rotor bushing110and the bracket120are firmly fixed to the rotor housing50by the coupling member160. For this purpose, a plurality of coupling holes115are formed at the rotor bushing110, and a plurality of insertion holes125are formed at the bracket120. The coupling holes115and the insertion holes125are formed at corresponding locations.

The coupling member160includes a body part161,163inserted into the rotor bushing110and the bracket120, and a flange part165having a greater diameter than the body part. The body part includes a first coupling part161is fixedly inserted into the coupling hole115, and a second coupling part163inserted into the insertion hole125. At the outer circumference of the first coupling part161is formed a screw thread engaged with the coupling hole115. Accordingly, the first coupling part161penetrates the rotor housing50to be coupled to the coupling hole115. The second coupling part163fixes the first vibration-absorbing member140while penetrating the insertion hole125. And, the flange part165is formed between the first coupling part161and the second coupling part163to prevent the bracket120from being directly contacted with the rotor housing50.

The first vibration-absorbing member140is fixedly inserted into the insertion hole125of the bracket120. The first vibration-absorbing member140is a hollow cylindrical shape enclosing the outer circumference of the second coupling part163, and the second coupling part163is inserted into the interior of the first vibration-absorbing member140, so that the vibration-absorbing member140is firmly fixed to the bracket120. At this time, the first vibration-absorbing member140has a head part141at the upper end thereof. The head part141prevents the flange part165from being directly contacted with the bracket120.

Meanwhile, the first and second vibration-absorbing members140and150are preferably made of elastic material such as rubber.

In summary, the first vibration-absorbing member140is installed between the rotor housing50and the bracket120, to absorb the vibration of the rotor housing50. Accordingly, it is prevented that the vibration of the rotor housing50is transferred to the bracket120. This means that the vibration of the rotor housing50is not transferred to the lower pulsator shaft31. Also, the second vibration-absorbing member150is installed between the rotor bushing110and the power breaking member130, to absorb the vibration of the rotor bushing110. Accordingly, it is prevented that the vibration of the rotor bushing110is transferred to the power breaking member130. This means that the vibration of the rotor bushing110is not transferred to the washing tub shaft20.

Operation of the washing machine according to the present invention is described as follows.

First,FIG. 3illustrates a status of a washing cycle. The coupling ascends with the help of an ascent inducing member such as a clutch assembly (not shown). At this time, the coupling70ascends along the outer circumference of the washing tub shaft20until the protruded part71is inserted into the insertion groove15of the bearing housing10. As a result, the washing tub shaft20is separated from the power breaking member130.

In this state, the rotor housing50is rotated by an interaction of the rotor5and the stator3. The rotational force of the rotor housing50is transferred to the rotor bushing110and at the same time is transferred to the bracket120via the coupling member160. Also, the vibration of the rotor bushing110is attenuated by the second vibration-absorbing member150.

After that, the rotational force of the rotor housing50is transferred to the lower pulsator shaft31, the decelerator40and the upper33in the named order. In this procedure, the RPM of the lower pulsator shaft31is properly decelerated through the decelerator40, and is then transferred to the upper pulsator shaft33. Accordingly, the upper pulsator shaft33rotates the pulsator at a low speed, so that water stream is generated inside the washing tub.

Next,FIG. 5illustrates a status of the dehydration cycle. Referring toFIG. 5, the coupling descends by the weight of itself or with the help of the clutch assembly. At this time, the coupling70descends along the outer circumference of the washing tub shaft20and the outer circumference of the power breaking member130, to constrain the washing tub shaft20and the power breaking member130at the same time.

In this state, the rotational force of the rotor housing50is transferred to the rotor bushing and at the same time is transferred to the bracket120via the coupling member160. During this procedure, the vibration of the rotor housing50is attenuated by the first vibration-absorbing member140. Also, the vibration of the rotor bushing110is attenuated by the second vibration-absorbing member150.

After that, the rotational force of the rotor housing50is transferred to the lower pulsator shaft31, and is continuously transferred to the washing tub shaft20via the power breaking member130and the coupling70. Accordingly, the washing tub shaft20is rotated along with the lower pulsator shaft31and the upper pulsator shaft33at the same speed. Accordingly, the washing tub is rotated at a high speed, so that washing water is removed by centrifugal force.

While the aforementioned embodiments show and describe vibration-preventive structure of the driving part of a washing machine having all the pulsator shaft31,33and the washing tub shaft20, they can be naturally applied to a washing machine in which washing cycle and dehydration cycle are performed by a single driving shaft by controlling the rotational speed of the driving part.

According to a washing machine of the present invention, at least one vibration-absorbing member is provided on a path where a power of the driving part is transferred to the washing tub or outer tub, thereby capable of absorbing the vibration of the driving part. Accordingly, it is prevented that the vibration of the driving part, in particular the vibration due to the ripple phenomenon is transferred to the washing tub or outer tub, so that it becomes possible to reduce a set noise considerably as a whole.