CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based on and claims priority under 35 U.S.C. § 119 of a Korean patent application number 10-2019-0177789, filed on Dec. 30, 2019, in the Korean Intellectual Property Office, which claims the benefit of Japanese patent application number 2019-006280, filed on Jan. 17, 2019, in the Japan Patent Office, and of a Japanese patent application number 2019-018807, filed on Feb. 05, 2019, in the Japan Patent Office, the disclosure of each of which is incorporated by reference herein in its entirety.

BACKGROUND

1. Field

The disclosure relates to a drive unit suitable for a washing machine and a washing machine having the same.

2. Description of Related Art

Various kinds of washing machines are currently commercialized. The washing machines may be roughly classified into a vertical type washing machine that rotates a rotating tub storing laundry in a vertical axis direction (i.e., a top loading washing machine), and a drum type washing machine that rotates a rotating tub storing laundry in a horizontal axis direction or in an inclined direction. In the trend, the drum type washing machine has become popular. These washing machines are all driven by a motor.

In the case of a drum type washing machine, a series of washing processes such as washing, rinsing, and dehydration are performed by rotating the drum storing the laundry. In the washing or rinsing process for rotating the laundry containing a large amount of water, a high torque rotational force at a low speed is required. In the dehydration process for rotating the laundry to make the laundry contain little water, a low torque rotational force at a high speed is required.

Therefore, the motor for driving the washing machine needs to cope with this rotational force. For this purpose, reducers and clutches are generally used. For example, it is possible to decelerate through a pulley and a belt between a motor and an output shaft, or through a plurality of gears, such as a planetary gear mechanism. In addition, driving states may be switched by interposing a clutch.

Examples of such a reducer and a clutch are disclosed in patent documents 1˜4 of the related art. As for the reducer and clutch disclosed in patent documents, the reducer and the clutch switch two output shafts, the clutch is arranged on the outside of the motor, or the reducer and the clutch are arranged side by side in the axial direction.

The above-mentioned washing machine is a washing machine in which a motor indirectly drives a drive object (i.e., indirect type drive type), which is different from a washing machine in which a motor directly drives a drive object (i.e., direct type drive type). Instead of the reducer and clutch, inverter control is performed in the direct type washing machine.

According to the technique disclosed, patent document 5 discloses a clutch configured to perform switching by sliding a slider by using an electromagnetic force. However, the slider of this document has an adsorber of a metallic material, and the sliding against the elastic force of a spring is performed by adsorbing this adsorber by using the electromagnetic force.

The clutch of patent document 5 generates an electromagnetic force by supplying electric power at all times in order to maintain the slider at a predetermined position.

RELATED ART DOCUMENTS

[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-778

[Patent Document 2] Japanese Patent Application Laid-Open No. 2006-517126

[Patent Document 3] Japanese Patent Application Laid-Open No. 2017-99605

[Patent Document 4] Japanese Patent Application Laid-Open No. 2010-240006

[Patent Document 5] Japanese Patent Application Laid-Open No. 2001-017778

The above information is presented as background information only to assist with an understanding of the disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the disclosure.

SUMMARY

Aspects of the disclosure are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the disclosure to provide a drive unit suitable for driving a washing machine by efficiently combining the direct drive method and the indirect drive method.

As for a washing machine, the large capacity and the low noise with the compact size are needed and further the washing machine is needed to be energy saving.

As for a direct drive type washing machine, it is needed to control a rotational force having a large speed difference or torque difference and to output the rotational force to a single motor having the same magnetic configuration. Therefore, it is needed to drive the motor in a greatly different rotational state and thus it is difficult to maintain an optimal rotational performance state. In addition, it is needed for the motor itself to have a large size so as to cope with such rotation performance state.

On the other hand, as for an indirect drive type washing machine, a reducer or a clutch is interposed between a drive target and a motor. Therefore, a large space for installing the reducer and the clutch is needed, which causes the limitation in the washing capacity. In addition, the mechanical structure is complicated, such as two output shafts. The complicated structure may cause the large noise.

Both the direct drive method and the indirect drive method have strengths and weaknesses, respectively.

Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments.

In accordance with an aspect of the disclosure, a driver (e.g., a drive unit) for a washing machine is provided. The driver includes a unit base, a shaft supported on the unit base in a state rotatable about a rotation axis, a motor to rotate the shaft, and a reducer interposed between the shaft and the motor. The motor and the reducer are integrally formed to be aligned in a line in a direction substantially perpendicular to the rotation axis.

According to the driver, a rotational force of the motor may be output from one shaft, Therefore, it is possible to simplify the structure. The motor and the reducer are integrally formed to be aligned in a line in a direction substantially perpendicular to the rotation axis. Accordingly, the driver may become thinner, and thus the entire driver may be made compact. A washing capacity may be increased, so it is suitable for a washing machine.

The term “aligned in a line” refers to an arrangement in the case of viewing the longitudinal section of the drive unit, and includes not only the objects lined up in a straight line, but also the cases in which the objects line up in a misaligned state with a certain degree. It is required that at least a part of each object just overlap in a column direction.

Particularly, the motor may include a rotor rotatably supported about the rotation axis, and a stator fixed to the unit base to face the rotor with a predetermined gap. The reducer may include a carrier fixed to the shaft, a sun gear configured to pivot about the rotation axis, an internal gear arranged around the sun gear, and a plurality of planetary gears rotatably supported by the carrier to be arranged between the sun gear and the internal gear so as to be engaged with the sun gear and the internal gear. The rotor, the stator, the sun gear, the plurality of planetary gears, and the internal gear may be aligned in a line substantially perpendicular to the rotation axis.

Further, because the rotor is rotatably supported on the shaft through a rotor bearing portion, the rotor, the stator, the sun gear, the plurality of planetary gears, the internal gear and the rotor bearing portion may be aligned in a line substantially perpendicular to the rotation axis.

In accordance with another aspect of the disclosure, a driver includes a unit base, a shaft supported on the unit base in a state rotatable about a rotation axis, a motor to rotate the shaft, and a reducer and a clutch interposed between the shaft and the motor. The motor and the clutch are integrally formed to be aligned in a line in a direction substantially perpendicular to the rotation axis.

The motor and the reducer may be integrally formed to be aligned in a line in a direction substantially perpendicular to the rotation axis. Accordingly, the drive driver may become thinner, and thus the entire driver may be made compact. A washing capacity may be increased, so it is suitable for a washing machine.

Particularly, the motor may include a rotor rotatably supported about the rotation axis, and a stator fixed to the unit base to face the rotor with a predetermined gap. The clutch may include a movable portion slidable in a rotation axis direction, and a pair of fixed portions spaced apart in the rotation axis direction. By connecting the movable portion to any one of the fixed portion, the clutch may switch a mode into a first mode in which the motor rotates the shaft through the reducer, and a second mode in which the motor rotates the shaft without using the reducer. The rotor, the stator, the sun gear, the movable portion and the fixed portion may be aligned in a line substantially perpendicular to the rotation axis.

In accordance with another aspect of the disclosure, a driver is provided. The driver includes a unit base, a shaft supported on the unit base in a state rotatable about a rotation axis, a motor to rotate the shaft, and a reducer and a clutch interposed between the shaft and the motor. The reducer and the clutch are integrally formed to be aligned in a line in a direction substantially perpendicular to the rotation axis.

The reducer and the clutch may be integrally formed to be aligned in a line in a direction substantially perpendicular to the rotation axis, Accordingly, the drive unit may become thinner, and thus the entire drive unit may be made compact. A washing capacity may be increased, so it is suitable for a washing machine

Particularly, the reducer may include a carrier fixed to the shaft, a sun gear to pivot about the rotation axis, an internal gear arranged around the sun gear, and a plurality of planetary gears rotatably supported by the carrier to be arranged between the sun gear and the internal gear so as to be engaged with the sun gear and the internal gear. The clutch may include a movable portion slidable in a rotation axis direction, and a pair of fixed portions spaced apart in the rotation axis direction. By connecting the movable portion to any one of the fixed portion, the clutch may switch a mode into a first mode in which the motor rotates the shaft through the reducer, and a second mode in which the motor rotates the shaft without using the reducer. The sun gear, the plurality of planetary gears, the internal gear, the movable portion and the fixed portion may be aligned in a line substantially perpendicular to the rotation axis.

In accordance with another aspect of the disclosure, a driver includes a unit base, a shaft supported on the unit base in a state rotatable about a rotation axis, a motor to rotate the shaft, and a reducer and a clutch interposed between the shaft and the motor. The motor, the reducer and the clutch are integrally formed to be aligned in a line in a direction substantially perpendicular to the rotation axis.

The motor, the reducer and the clutch may be integrally formed to be aligned in a line in a direction substantially perpendicular to the rotation axis. Accordingly, the driver may become thinner, and thus the entire driver may be made compact. A washing capacity may be increased, so it is suitable for a washing machine.

Particularly, the motor may include a rotor rotatably supported about the rotation axis, and a stator fixed to the unit base to face the rotor with a predetermined gap. The reducer may include a carrier fixed to the shaft, a sun gear to pivot about the rotation axis, an internal gear arranged around the sun gear, and a plurality of planetary gears rotatably supported by the carrier to be arranged between the sun gear and the internal gear so as to be engaged with the sun gear and the internal gear. The clutch may include a movable portion slidable in a rotation axis direction, and a pair of fixed portions spaced apart in the rotation axis direction. By connecting the movable portion to any one of the fixed portion, the clutch may switch a mode into a first mode in which the motor rotates the shaft through the reducer, and a second mode in which the motor rotates the shaft without using the reducer. The rotor, the stator, the sun gear, the plurality of planetary gears, the internal gear, the movable portion, and the fixed portion may be aligned in a line substantially perpendicular to the rotation axis.

Further, because the rotor is rotatably supported on the shaft through a rotor bearing portion, the rotor, the stator, the sun gear, the plurality of planetary gears, the internal gear, the movable portion, the fixed portion and the rotor bearing portion may be aligned in a line substantially perpendicular to the rotation axis.

As for the driver, the rotor may include a plurality of magnets, and the plurality of magnets may face an outer circumferential portion of the stator.

As for the driver, the rotor may include a cylindrical rotor case formed in such a way that a height of a circumferential wall is smaller than a radius of a bottom wall and a bottom has a center coinciding with the rotation axis. The rotor, the stator, the sun gear, the plurality of planetary gears, the internal gear, the movable portion, the fixed portion and the rotor bearing portion may be accommodated in the rotor case.

Therefore, almost all of the driver may be accommodated in the rotor case of the motor, and thus the driver may be more compact.

As for the driver, the rotor case may further include a shaft support to be supported by the rotor bearing portion, and the shaft support may serve as the sun gear.

Therefore, the driver may be configured more efficiently by sharing the members

In accordance with another aspect of the disclosure, a washing machine is provided. The washing machine includes a fixed tub installed inside a body, a rotating tub rotatably disposed in the fixed tub to accommodate laundry, and the above-mentioned drive unit.

The unit base may be installed on a bottom of the fired tub, the shaft passing through the bottom of the fixed tub may be fixed to the rotating tub and thus the rotating tub may be rotated about the rotation axis.

That is, the compact driver mentioned above may be used for the washing machine and particularly the driver may be installed on the bottom of the fixed tub so as to rotate the rotating tub. Therefore, the capacity of the fixed tub and the rotating tub may be enlarged.

The washing machine may further include at least one processor configured to perform at least each process of washing, rinsing, and dehydration, by controlling the driver and the at least one processor may switch a mode into the first mode in the washing and rinsing process and switches a mode into the second mode in the dehydration process.

Accordingly, by the driver, it is possible to output the rotational force corresponding to each process performed by the washing machine and thus it is possible to operate efficiently.

As for the washing machine, the rotation axis may be arranged to extend in a direction that is inclined with respect to the horizontal direction or in a substantially horizontal direction.

The embodiment may be applied to the drum type washing machine Because as for the drum type washing machine, the output of a driving force is applied to only a drum, it is suitable for the drive unit mentioned above. It is possible to realize a washing machine with ease and convenience.

In accordance with another aspect of the disclosure, a driver is provided, The driver includes a shaft, a motor to rotate the shaft, a clutch interposed between the shaft and the motor, and a reducer configured to use a planetary gear mechanism. The clutch includes a movable portion slidable in a rotation axis direction, a pair of fixed portions spaced apart in the rotation axis direction, and an actuator to switch a connection state of the reducer by connecting the movable portion to any one of the fixed portion by sliding the movable portion. The actuator includes a movable element provided in the movable portion and including a clutch magnet, and a fixed element arranged to face the movable element with a gap therebetween in a diameter direction and including a clutch coil and a clutch yoke. The clutch magnet includes a plurality of magnetic poles arranged in the rotation axis direction.

Particularly, the driver may be configured as follows.

In accordance with another aspect of the disclosure, a driver includes a unit base, a shaft supported on the unit base in a state rotatable about a rotation axis, a motor to rotate the shaft, and a reducer and a clutch interposed between the shaft and the motor.

The motor may include a rotor rotatably supported about the rotation axis, and a stator fixed to the unit base to face the rotor with a predetermined gap.

The reducer may include a carrier fixed to the shaft, a sun gear to pivot about the rotation axis, an internal gear arranged around the sun gear, and a plurality of planetary gears rotatably supported by the carrier to be arranged between the sun gear and the internal gear so as to be engaged with the sun gear and the internal gear.

The clutch may include a movable portion slidable in a rotation axis direction, a pair of fixed portions including first and second fixed portions spaced apart in the rotation axis direction, and an actuator to slide the movable portion. The clutch may be configured to be switchable between a first mode in which the motor rotates the shaft through the reducer as the movable portion is connected to the first fixed portion, and a second mode in which the motor rotates the shaft without using the reducer as the movable portion is connected to the second fixed portion.

The actuator may include a movable element provided in the movable portion and including a clutch magnet, and a fixed element arranged to face the movable element with a gap therebetween in a diameter direction and including a clutch coil and a clutch yoke. The clutch magnet may include a plurality of magnetic poles arranged in the rotation axis direction.

According to this driver, the clutch and the reducer may be provided between the shaft and the motor outputting a driving force. That is, because the clutch and the reducer are integrally formed, the entire unit may be made compact. It is possible to perform two types output such as decelerated output and output without deceleration, using a single shaft. Therefore, it is suitable for the washing machine to perform a washing process or a dehydration process.

The clutch may switch the connection state of the reducer by sliding the movable portion where the movable element of the actuator is installed in the rotation axis direction. Because the movable portion includes a clutch magnet having a plurality of magnetic poles arranged in the rotation axis direction, the movable portion may be slid by supplying a current to the clutch coil of the fixed element. Further, it is possible to maintain the connection state of the movable portion due to the action of the electromagnetic force acting between the clutch yoke and the clutch magnet.

Therefore, the electric power consumption may be suppressed because a current is supplied to the clutch coil only when the clutch is switched.

A first stable point magnetically stabilized on any one side of the connecting portion of the movable portion and the fixed portion and a second stable point magnetically stabilized on the other side of the connection portion may be generated when a current is not supplied to the clutch coil.

Particularly, it is appropriate that the clutch magnet includes three magnetic poles, and the clutch yoke includes end magnetic poles positioned at both ends of the magnetic poles and a pair of magnetic pole facing portion provided to face to each other.

Therefore, the connection state of the movable portion nay be maintained more stably.

In the washing machine, the fixed portion may include a fixed side protruding in the rotation axis direction, and the movable portion may include a pair of movable side protrusions engaged with the fixed side protrusion when being connected to the fixed portion. The washing machine may further include a position selector to position the fixed portion and the movable portion on a predetermined position in the circumferential direction in which the fixed side protrusion is engaged with the movable side protrusion.

Because the fixed portion and the movable portion are connected by the engagement of the fixed side protrusion and the movable side protrusion, such a stable connection state may be secured by a simple configuration. Because the position selector is provided, the fixed portion and the movable portion may be smoothly engaged with each other even when the movable side protrusion is shifted in the circumferential direction with respect to the fixed side protrusion.

The washing machine may further include an impact absorbing member to reduce an impact at the time of connection to the connection portion of the movable portion and the fixed portion.

The movable portion may be slid and then connected to the fixed portion. Therefore, at the time of connection, an unpleasant impact sound may occur according to this contact. On the other hand, when the impact absorbing member, such as an elastic member or a vibration damping member, is provided at the connection portion of the movable portion and the fixed portion, the impact sound may be reduced.

The washing machine may further include at least one processor configured to control the motor and the clutch. The at least one processor may include a motor controller configured to control driving of the motor, and a clutch controller configured to control driving of the clutch. The clutch controller and the motor controller may share a control circuit.

Therefore, it is possible to prevent an increase in the number of components, such as a semiconductor element, and thus the washing machine may be implemented at low cost.

Immediately before the clutch controller supplies a predetermined switching current to the clutch to connect the movable portion to the fixed portion, the clutch controller may supply an impact relaxation current, which is an opposite direction to the switching current, to the clutch.

Therefore, the impact sound may be simply reduced without performing structural studies.

In accordance with another aspect of the disclosure, a washing machine is provided. The washing machine includes a body, a fixed tub installed inside the body, a rotating tub rotatably disposed in the fixed tub to accommodate laundry, and a driver configured to rotate the rotating tub. The driver includes a shaft connected to a bottom of the rotating tub to rotate the rotating tub about a rotation axis, a motor including a stator and a rotor rotatable through interaction with the stator, a reducer to connect the rotor to the shaft to rotate the shaft, and a clutch switchable between a first mode in which the motor reduces a speed through the reducer and then the motor rotates the shaft at a reduced speed, and a second mode in which the motor rotates the shaft without reducing the speed. The reducer and the clutch are arranged between the shaft and the motor.

The reducer, the clutch, and the motor may be arranged in a lime along a direction perpendicular to the rotation axis.

The rotor may include a rotor case and a plurality of magnets. The plurality of magnets may be arranged to face an outer circumferential portion of the stator.

The rotor case may include a disk-shaped bottom wall in which a center thereof coincides with the rotation axis, and a cylindrical circumferential wall extending around the bottom wall. The stator, the reducer, and the clutch may be accommodated in the rotor case.

The rotor case may include a shaft support rotatably supported on the shaft through a rotor bearing portion.

The washing machine may further include at least one processor configured to perform at least each process of washing, rinsing, and dehydration, by controlling the driver, and the at least one processor may be further configured to control the clutch to switch into the first mode in the washing and rinsing process, and control the clutch to switch into the second mode in the dehydration process.

The reducer may include a carrier fixed to the shaft, a sun gear to pivot about the rotation axis, an internal gear arranged around the sun gear, and a plurality of planetary gears rotatably supported by the carrier to be arranged between the sun gear and the internal gear so as to be engaged with the sun gear and the internal gear.

The clutch may include a movable portion slidable in a rotation axis direction, a pair of fixed portions spaced apart in the rotation axis direction, and an actuator to switch the mode between the first mode and the second mode by connecting the movable portion to any one of the pair of fixed portions.

The pair of fixed portions may include a first fixed portion fixed to the stator and a second fixed portion fixed to the rotor

The movable portion may be formed of a cylindrical member having a diameter larger than that of the internal gear, and may be arranged on the outside of the internal gear to be slidable in the rotation axis direction.

The pair of fixed portions each may include a pair of locking protrusions protruding in the rotation axis direction, and the movable portion may include a pair of hooking protrusions formed to be spaced apart in the rotation axis direction to be engaged with the pair of locking protrusions.

The actuator may include a movable element provided on the movable portion and including a clutch magnet, and a fixed element provided to face the movable element with a gap therebetween in a diameter direction and including a clutch coil and a clutch yoke. The clutch magnet may include a plurality of magnetic poles arranged in the rotation axis direction.

A first stable point, in which the movable element is magnetically stabilized on any one side of a connection portion where the movable portion is connected to the fixed portion, and a second stable point, in which the movable element is magnetically stabilized on the other side of the connection portion, may be generated when a current is not supplied to the clutch coil.

The clutch may include a position selector to allow the fixed portion and the movable portion to be placed on a predetermined position in a circumferential direction where the locking protrusion is engaged with the hooking protrusion.

The washing machine may further include at least one processor configured to control the motor and the clutch. The at least one processor may include a motor controller configured to control driving of the motor, and a clutch controller configured to control driving of the clutch. Immediately before the clutch controller supplies a predetermined switching current to the clutch to connect the movable portion to the fixed portion, the clutch controller may supply an impact relaxation current, which is an opposite direction to the switching current, to the clutch.

Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the disclosure.

