Patent Description:
A washing machine is driven in two main operating modes (washing mode, dehydration mode) with different operating conditions.

In order to satisfy both of the above two main operating modes, the washing machine is provided with a planetary gear set and a clutch, and operates an output shaft with a low speed and high torque with a gear ratio of n:<NUM> (washing mode), or operates the output shaft with a high speed and low torque with a gear ratio of <NUM>:<NUM> (dehydration mode).

Here, the output shaft refers to a shaft coupled to a drum to rotate the drum. The drum may be referred to as an "inner tub".

That is, in a typical washing machine, after a washing mode or a rinsing mode is terminated, the motor is temporarily stopped and a draining operation is performed. And, after the draining operation is completed, an initial dehydration mode starts.

However, since high torque is required to initially start wet laundry in the initial dehydration mode, the output shaft should be operated at low speed and high torque.

Moreover, in order to start the dehydration mode after the initial dehydration mode is completed, the output shaft should be operated at high speed and low torque.

Therefore, the washing machine drive system has components for changing a rotational force of a rotor shaft transmitted to the output shaft between the initial dehydration mode and the dehydration mode, such as a planetary gear set and a clutch.

As an example of a related art related to the present disclosure, Korean Patent No. <CIT> (hereinafter referred to as "prior art") discloses a structure in which the position of a reduction coupling unit including a planetary gear set is moved forward and backward using a lever while changing the gear ratio.

That is, in the case of the prior art, in an initial dehydration mode, the reduction coupling unit moves forward according to the operation of a lever of a lever unit, and accordingly, the teeth formed on a coupling cap of the reduction coupling unit engage with the teeth formed on the drum, so that the washing machine operates at low speed and high torque.

In addition, in the dehydration mode, the reduction coupling unit moves backward according to the operation of the lever of the lever unit, and accordingly, the teeth formed on the coupling housing of the reduction coupling unit engage with the teeth formed on the rotor housing, so that the washing machine operates at high speed and low torque.

However, according to the drive system disclosed in the prior patent, since the pinion gear equipped on the carrier of the reduction coupling unit should move axially with respect to the sun gear, only a spur gear, not a helical gear, can be used as the pinion gear and the sun gear, which causes a problem of noise.

In addition, since the forward and backward movement of the reduction coupling unit is possible only when the motor is stopped, there is a problem that the motor should be stopped for mode switching.

In addition, the sun gear equipped in the planetary gear set is mounted on the bearing on the output shaft, and the output shaft is supported by only one bearing.

Therefore, in the initial dehydration mode, the planetary gear set acts as a support point, and the output shaft is supported by the planetary gear set and the bearing, but in the dehydration mode, the rotor, the planetary gear set, and the output shaft operate as one, and the output shaft is supported by only one bearing, so there is a problem of low durability in the dehydration mode in which the operation is performed at high speed and low torque.

Further washing machine drive systems of the prior art are disclosed, for instance, in <CIT>, <CIT>, and <CIT>.

An object of the present invention seeks to solve is to provide a washing machine drive system that can apply a reduction ratio while maintaining the rotation of a rotor by implementing a neutral mode of a clutch.

In addition, an object of the present invention is to provide a washing machine drive system that can generate high torque by applying a reduction ratio without stopping the rotation of the rotor.

In addition, an object of an embodiment of the present invention is to provide a washing machine drive system that can apply a helical gear to the detailed configuration of a planetary gear set.

In addition, an object of an embodiment of the present invention is to provide a washing machine drive system that can improve space efficiency while making the rotational speed of a sun gear and the rotational speed of a carrier different.

In addition, an object of an embodiment of the present invention is to provide a washing machine drive system that can improve space efficiency while making the rotational speed of a carrier and the rotational speed of a ring gear different.

In addition, an object of an embodiment of the present invention is to provide a washing machine drive system that can stop the rotation of a ring gear that is spline-coupled with the clutch actuator by coupling a clutch actuator to a clutch stator.

In addition, an object of an embodiment of the present invention is to provide a washing machine drive system that can rotate the ring gear that is spline-coupled with the clutch actuator together with the rotor by coupling the clutch actuator to the rotor.

In addition, an object of an embodiment of the present invention is to provide a washing machine drive system that can reduce power consumption by maintaining the position of the clutch actuator even when the clutch actuator is moved in a vertical direction and the supply of current is stopped.

In addition, an object of an embodiment of the present invention is to provide a washing machine drive system that can improve space efficiency and reduce size.

In addition, an object of an embodiment of the present invention is to provide a washing machine drive system that can maintain the position of the clutch actuator even when the supply of current to first to third coils is stopped by forming three stable points.

According to the present invention, there is provided a washing machine drive system according to claim <NUM>, the washing machine drive system including: a housing; a motor stator coupled to the housing; a rotor facing the motor stator; an output shaft bearing-coupled to the housing; a planetary gear set coupled to the rotor and spline-coupled to an outer peripheral surface of the output shaft; a clutch stator coupled to the motor stator; and a clutch actuator spline-coupled to an outer peripheral surface of the planetary gear set so as to be vertically movable and facing the clutch stator.

In this case, the clutch stator includes first to third coils arranged in parallel in a vertical direction, the clutch actuator is fixed to the rotor and transmits rotational force of the rotor to the output shaft at a <NUM>:<NUM> ratio when current is supplied to the first coil, the clutch actuator is fixed to the clutch stator, reduces the rotational force of the rotor at a gear ratio of n:<NUM>, and transmits the reduced rotational force to the output shaft when current is supplied to the third coil, and the clutch actuator is disengaged from the rotor or the clutch stator when current is supplied to the second coil.

Accordingly, a neutral mode of the clutch is implemented, and thus, a reduction ratio can be applied while maintaining the rotation of the rotor.

In addition, since the reduction ratio is applied without stopping the rotation of the rotor, an initial dehydration mode can be entered, so high torque can be generated.

The planetary gear set may include a sun gear coupled to the rotor, a plurality of pinion gears coupled with an outer surface of the sun gear and spaced apart in a circumferential direction, a ring gear whose inner peripheral surface is coupled with the plurality of pinion gears and whose outer peripheral surface is spline-coupled with the clutch actuator, and a carrier coupled with the plurality of pinion gears and spline-coupled to the outer peripheral surface of the output shaft.

Accordingly, since the pinion gear does not need to move axially with respect to the sun gear, the helical gear can be applied to detailed configurations of the planetary gear set.

The washing machine drive system may further include a sun gear bearing arranged between the carrier and the sun gear.

Accordingly, space efficiency can be improved while making the rotational speed of the sun gear and the rotational speed of the carrier different.

The sun gear bearing may overlap the first and second coils in a direction perpendicular to the output shaft.

Therefore, it is possible to reduce the size of the washing machine drive system.

The washing machine drive system may further include a ring gear bearing arranged between the carrier and the ring gear.

Accordingly, space efficiency can be improved while making the rotational speed of the carrier and the rotational speed of the ring gear different.

A vertical center area of the plurality of pinion gears may be arranged between the first coil and the second coil in a direction perpendicular to the output axis.

The plurality of pinion gears may overlap the first and second coils in a direction perpendicular to the output shaft, and may not overlap the third coil in a direction perpendicular to the output shaft.

An upper surface of the ring gear may overlap the third coil in a direction perpendicular to the output shaft, and a lower surface of the ring gear may be arranged below the first coil in the direction perpendicular to the output shaft.

Moreover, the clutch actuator may include a first clutch portion formed on an upper surface of the clutch, the clutch stator may include a second clutch portion formed on a surface facing the upper surface of the clutch actuator, and the first clutch portion may be engaged and coupled with the second clutch portion when current is supplied to the third coil.

Therefore, by coupling the clutch actuator to the clutch stator, the rotation of the ring gear spline-coupled to the clutch actuator can be stopped.

The clutch actuator may include a third clutch portion formed on a lower surface of the clutch actuator, the rotor may include a fourth clutch portion formed on a surface facing the lower surface of the clutch actuator, and the third clutch portion may be engaged and coupled with the fourth clutch portion when current is supplied to the first coil.

Therefore, by coupling the clutch actuator to the rotor, the ring gear spline-coupled to the clutch actuator can rotate together with the rotor.

The clutch actuator may include a clutch coupling portion spline-connected to the planetary gear set and a clutch magnet disposed in the clutch coupling portion and facing the clutch stator.

In this case, the coupling of the clutch actuator and the rotor may be maintained when current is supplied to the first coil and then the supply of current is stopped, the coupling of the clutch actuator and the clutch stator may be maintained when current is supplied to the third coil and then the supply of current is stopped, and decoupling of the clutch actuator and the rotor or the clutch stator may be maintained when current is supplied to the second coil and then the supply of current is stopped.

Accordingly, power consumption can be reduced because the position of the clutch actuator is maintained even when the clutch actuator is moved in the vertical direction and the supply of current is stopped.

A vertical length of the clutch magnet may be between <NUM> and <NUM> times a vertical length of each of the first to third coils.

Moreover, the clutch stator may include a stator coupling portion coupled to the motor stator, and first to third cores arranged in the stator coupling portion and arranged in parallel in a vertical direction.

In this case, the first coil may be arranged in the first core, the second coil may be arranged in the second core, the third coil may be arranged in the third core, and the first to third cores may be each formed in the same shape, and the first to third coils may be each formed in the same shape.

The stator coupling portion may include a circumferential portion extending inwardly in the circumferential direction from an upper surface of the stator coupling portion, a second clutch portion may be arranged on a lower surface of the circumferential portion, and a second clutch portion may overlap the clutch actuator in a vertical direction.

Accordingly, it is possible to improve space efficiency of the washing machine drive system.

The clutch actuator may include a clutch coupling portion spline-coupled to the planetary gear set, and a clutch magnet disposed in the clutch coupling portion and facing the clutch stator.

In this case, the clutch magnet may overlap the first coil, the second coil, the first core, and the second core in a horizontal direction when current is supplied to the first coil, the clutch magnet may overlap the second coil and the first to third cores in the horizontal direction when current is supplied to the second coil, and the clutch magnet may overlap the second coil, the third coil, the second core, and the third core in the horizontal direction when current is supplied to the third coil.

Moreover, the vertical center region of the clutch magnet may overlap the upper region of the first coil in the horizontal direction when current is supplied to the first coil, the vertical center region of the clutch magnet may overlap the vertical center region of the second coil in the horizontal direction when current is supplied to the second coil, and the vertical center region of the clutch magnet may overlap the lower region of the third coil in the horizontal direction when current is supplied to the third coil.

Accordingly, three stable points are formed so that the position of the clutch actuator can be maintained even when the supply of current to the first to third coils is stopped.

The clutch actuator and the clutch stator may be disposed between the planetary gear set and the motor stator in a direction perpendicular to the output shaft.

The rotor may include a rotor case including a disk portion sharing a center with the output shaft and a cylindrical portion extending upward from a radially outer side of the disk portion, and a rotor magnet disposed in the cylindrical portion and facing the motor stator.

In this case, the rotor magnet may overlap the second and third coils in a direction perpendicular to the output shaft and may not overlap the first coil in the direction perpendicular to the output shaft.

Therefore, it is possible to improve of space efficiency of the rotor and the motor stator.

According to the present invention, it is possible to provide a washing machine drive system that can apply a reduction ratio while maintaining the rotation of a rotor by implementing a neutral mode of a clutch.

According to the present invention, it is possible to provide a washing machine drive system that can generate high torque by applying a reduction ratio without stopping the rotation of the rotor.

According to an embodiment of the present invention, it is possible to provide a washing machine drive system that can apply a helical gear to the detailed configuration of a planetary gear set.

According to an embodiment of the present invention, it is possible to provide a washing machine drive system that can improve space efficiency while making the rotational speed of a sun gear and the rotational speed of a carrier different.

According to an embodiment of the present invention, it is possible to a washing machine drive system that can improve space efficiency while making the rotational speed of a carrier and the rotational speed of a ring gear different.

According to an embodiment of the present invention, it is possible to provide a washing machine drive system that can stop the rotation of a ring gear that is spline-coupled with the clutch actuator by coupling a clutch actuator to a clutch stator.

According to an embodiment of the present invention, it is possible to provide a washing machine drive system that can rotate the ring gear that is spline-coupled with the clutch actuator together with the rotor by coupling the clutch actuator to the rotor.

According to an embodiment of the present invention, it is possible to provide a washing machine drive system that can reduce power consumption by maintaining the position of the clutch actuator even when the clutch actuator is moved in a vertical direction and the supply of current is stopped.

According to an embodiment of the present invention, it is possible to provide a washing machine drive system that can improve space efficiency and reduce size.

According to an embodiment of the present invention, it is possible to provide a washing machine drive system that can maintain the position of the clutch actuator even when the supply of current to first to third coils is stopped by forming three stable points.

Hereinafter, embodiments disclosed in this disclosure will be described in detail with reference to the attached drawings, and regardless of the drawing symbols, identical or similar components will be given the same reference numerals and redundant descriptions thereof will be omitted.

When describing the embodiments disclosed in this disclosure, when it is mentioned that a component is "coupled" or "connected" to another component, it should be understood that it may be directly connected or connected to the other component, but other components may exist therebetween.

In addition, when describing the embodiments disclosed in this disclosure, in a case where it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this disclosure, the detailed description thereof will be omitted. In addition, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in the present disclosure, and the technical ideas disclosed in the present disclosure are not limited by the attached drawings.

Meanwhile, the term such as the disclosure may be replaced with terms such as document, specification, and description.

<FIG> and <FIG> are perspective views of a tub and a washing machine drive system of a washing machine according to one embodiment of the present invention.

Referring to <FIG> and <FIG>, the washing machine according to one embodiment of the present invention may include an inner tub <NUM>, a pulsator <NUM>, and a washing machine drive system <NUM>, but may be implemented excluding some of the configurations thereof, and does not exclude additional configurations.

The washing machine according to one embodiment of the present invention may be a top loading type washing machine in which a rotation center of the inner tub <NUM> is formed in a direction perpendicular to a bottom and is designed to allow laundry to be loaded from the upper side, and a front loading type washing machine in which the rotation center of the inner tub <NUM> is formed in a direction horizontal to the bottom or inclined in a direction that decreases toward the rear end and is designed to allow laundry to be loaded from the front.

The inner tub <NUM> may have a cylindrical shape with an open top or front. The pulsator <NUM> may be arranged on a bottom surface of the inner tub <NUM>. The inner tub <NUM> may be formed of a plastic material. The pulsator <NUM> may be connected to an output shaft <NUM> of the washing machine drive system <NUM>. The washing machine drive system <NUM> may be coupled to the inner tub <NUM> to rotate the pulsator <NUM>.

<FIG> is a perspective view of the washing machine drive system according to one embodiment of the present invention. <FIG> is an exploded perspective view of the washing machine drive system according to one embodiment of the present invention. <FIG> is a cross-sectional perspective view of the washing machine drive system according to one embodiment of the present invention. <FIG> is a partial cross-sectional perspective view of a clutch actuator, a clutch stator, and a rotor of the washing machine drive system according to one embodiment of the present invention. <FIG> is a view in which an upper carrier is removed in a planetary gear set of a washing machine drive system according to one embodiment of the present invention. <FIG> is a cross-sectional view of a partial configuration of the washing machine drive system according to one embodiment of the present invention. <FIG> is an enlarged view of the clutch actuator and the clutch stator region in a cross-section of the washing machine drive system according to one embodiment of the present invention.

Referring to <FIG>, the washing machine drive system <NUM> according to one embodiment of the present disclosure may include an output shaft <NUM>, a housing <NUM>, a first bearing <NUM>, a second bearing <NUM>, a motor stator <NUM>, a rotor <NUM>, a planetary gear set <NUM>, and a clutch <NUM>, but some of these components may be excluded and additional components are not excluded.

The output shaft <NUM> may be extended in an axial direction. The output shaft <NUM> may be coupled with the pulsator <NUM>. The output shaft <NUM> may be rotatably coupled to the housing <NUM>. The output shaft <NUM> may be bearing-coupled to the housing <NUM>. The output shaft <NUM> may be coupled to the planetary gear set <NUM>. The output shaft <NUM> may be spline-coupled to the carrier <NUM> of the planetary gear set <NUM>. Here, the spline refers to a groove or a groove cut into a shaft or a bore, and the spline-coupling may refer to a coupling that can rotate together while sliding in the axial direction. The output shaft <NUM> may rotate at the same speed as the carrier <NUM> of the planetary gear set <NUM>. In one embodiment of the present disclosure, the axial direction may be interpreted as a vertical direction based on <FIG> and <FIG>.

The pulsator <NUM> may be coupled to the upper region of the output shaft <NUM>. The central region of the output shaft <NUM> may be bearing-coupled to the housing <NUM>. A first bearing <NUM> and a second bearing <NUM> may be arranged between the central region of the output shaft <NUM> and the housing <NUM>.

The lower region of the output shaft <NUM> may be arranged inside the rotor <NUM>. The lower region of the output shaft <NUM> may be coupled to the planetary gear set <NUM>. The diameter of the lower region of the output shaft <NUM> may be smaller than the diameter of the central region. The axial length of the lower region of the output shaft <NUM> may be shorter than the axial length of the central region of the output shaft <NUM>.

The output shaft <NUM> may include a first spline portion <NUM> formed on an outer peripheral surface. The first spline portion <NUM> may protrude outwardly from the outer peripheral surface of the output shaft <NUM>. The first spline portion <NUM> may be arranged in a lower region of the output shaft <NUM>. The first spline portion <NUM> may be spline-coupled to the second spline portion <NUM> of the carrier <NUM> of the planetary gear set <NUM>.

The output shaft <NUM> may be rotatably coupled to the housing <NUM>. The pulsator <NUM> may be arranged in the upper portion of the housing <NUM>. The housing <NUM> may be coupled to the inner tub <NUM>. The motor stator <NUM>, the rotor <NUM>, the planetary gear set <NUM>, and the clutch <NUM> may be arranged in the lower portion of the housing <NUM>. The housing <NUM> may be coupled to the motor stator <NUM>. The housing <NUM> may be formed of a plastic material.

The first bearing <NUM> may be arranged between the output shaft <NUM> and the housing <NUM>. The first bearing <NUM> may bearing-couple the output shaft <NUM> to the housing <NUM>. The first bearing <NUM> may rotatably couple the output shaft <NUM> to the housing <NUM>. The first bearing <NUM> may extend in the circumferential direction. The first bearing <NUM> may be arranged above the second bearing <NUM>.

The second bearing <NUM> may be arranged between the output shaft <NUM> and the housing <NUM>. The second bearing <NUM> may bearing-couple the output shaft <NUM> to the housing <NUM>. The second bearing <NUM> may rotatably couple the output shaft <NUM> to the housing <NUM>. The second bearing <NUM> may extend in the circumferential direction. The second bearing <NUM> may be arranged below the first bearing <NUM>. The second bearing <NUM> may be arranged above the planetary gear set <NUM>. The second bearing <NUM> may be arranged above the carrier <NUM> of the planetary gear set <NUM>. The second bearing <NUM> may be arranged radially inwardly of the motor stator <NUM>. The second bearing <NUM> may be arranged radially inwardly of the clutch stators <NUM>, <NUM>, <NUM>, and <NUM>.

The motor stator <NUM> may be coupled to the housing <NUM>. The motor stator <NUM> may be arranged inside the rotor <NUM>. The motor stator <NUM> may face the rotor <NUM>. The motor stator <NUM> may be arranged above the clutch <NUM>. The motor stator <NUM> may be arranged above the clutch stators <NUM>, <NUM>, <NUM>, and <NUM>. The clutch stators <NUM>, <NUM>, <NUM>, and <NUM> may be coupled to the motor stator <NUM>.

The motor stator <NUM> may include a motor coupling portion <NUM>. The motor coupling portion <NUM> may be coupled to the housing <NUM>. The motor coupling portion <NUM> may be arranged below the housing <NUM>. A stator coupling portion <NUM> may be coupled to the motor couple portion <NUM>. The motor couple portion <NUM> may be arranged above the stator coupling portion <NUM>. The motor couple portion <NUM> may extend in a circumferential direction. A motor stator <NUM> may be arranged on an outer peripheral surface of the motor couple portion <NUM>.

The motor stator <NUM> may include the motor stator <NUM>. The motor stator <NUM> may be disposed radially outwardly of the motor couple portion <NUM>. The motor stator <NUM> may be coupled to the motor couple portion <NUM>. The motor stator <NUM> may be disposed radially inwardly of the rotor <NUM>. The motor stator <NUM> may face the rotor magnet <NUM>. The motor stator <NUM> may include a plurality of motor stator units spaced apart in the circumferential direction. The motor stator unit may include a motor stator core formed on an outer peripheral surface of the motor couple portion <NUM>, a motor coil wound around the motor stator core, and a yoke coupled to the motor stator core. The motor stator <NUM> may rotate the rotor magnet <NUM> through electromagnetic interaction.

The rotor <NUM> may face the motor stator <NUM>. The rotor <NUM> may be coupled with the planetary gear set <NUM>. The rotor <NUM> may be coupled with a sun gear <NUM> of the planetary gear set <NUM>. Therefore, the rotor <NUM> may supply a rotational force to the output shaft <NUM>.

The rotor <NUM> may include a rotor magnet <NUM>. The rotor magnet <NUM> may be disposed in a rotor case <NUM>. The rotor magnet <NUM> may be disposed on an inner peripheral surface of a cylindrical portion <NUM> of the rotor case <NUM>. The rotor magnet <NUM> may face the motor stator <NUM>. The rotor magnet <NUM> may face the motor stator <NUM> of the motor stator <NUM>. When current is supplied to the motor stator <NUM> of the motor stator <NUM>, the rotor magnet <NUM> may rotate in one direction or the other direction due to electromagnetic interaction.

The rotor magnet <NUM> may overlap a second coil <NUM> and a third coil <NUM> in a direction perpendicular to or horizontal to the output shaft <NUM>. The rotor magnet <NUM> may not overlap the first coil <NUM> in the direction perpendicular to or horizontal to the output shaft <NUM>. Accordingly, the space efficiency of the rotor <NUM> and the motor stator <NUM> can be improved.

The rotor magnet <NUM> may include a plurality of rotor magnet units spaced apart in the circumferential direction. Each of the plurality of rotor magnet units may face each of the plurality of motor stator units.

The rotor <NUM> may include a rotor case <NUM>. The rotor case <NUM> may include a disk portion <NUM> sharing a center with the output shaft <NUM> and a cylindrical portion <NUM> extending upwardly from the radial outer side of the disk portion <NUM>. A rotor magnet <NUM> may be arranged on an inner peripheral surface of a cylindrical portion <NUM>. A disk portion <NUM> may be coupled with the planetary gear set <NUM>. The disk portion <NUM> may be coupled with the sun gear <NUM> of the planetary gear set <NUM>. A fourth clutch portion <NUM> may be formed in the disk portion <NUM>. The fourth clutch portion <NUM> may be formed on an upper surface of the disk portion <NUM>. The fourth clutch portion <NUM> may face a third clutch portion <NUM> of clutch actuators <NUM> and <NUM>. The fourth clutch portion <NUM> may be engaged and coupled with the third clutch portion <NUM> of the clutch actuators <NUM> and <NUM>. The fourth clutch portion <NUM> may extend in the circumferential direction. The fourth clutch portion <NUM> may be formed of a plurality of protrusions spaced apart from each other in the circumferential direction.

The motor stator <NUM> and the rotor <NUM> may be referred to as a "motor'.

The planetary gear set <NUM> may be spline-coupled to the outer peripheral surface of the output shaft <NUM>. The planetary gear set <NUM> may be coupled to the rotor <NUM>. The planetary gear set <NUM> may rotate integrally with the rotor <NUM>. The planetary gear set <NUM> may transmit the rotational force of the rotor <NUM> to the output shaft <NUM>.

Specifically, according to the vertical movement of the clutch actuators <NUM> and <NUM>, the planetary gear set <NUM> may transmit the rotational force of the rotor <NUM> to the output shaft <NUM> by reducing the rotational force with a gear ratio of <NUM>:<NUM> or n:<NUM>. For example, when the clutch actuators <NUM> and <NUM> moves upward and is fixed to the clutch stators <NUM>, <NUM>, <NUM>, and <NUM>, a part of the planetary gear set <NUM> spline-coupled with the clutch actuators <NUM> and <NUM> is fixed, so that the rotational force of the rotor <NUM> may be transmitted to the output shaft <NUM> while being reduced with a gear ratio of n:<NUM>. In contrast, when the clutch actuators <NUM> and <NUM> moves downward and is fixed to the rotor <NUM>, the clutch actuators <NUM> and <NUM> and the planetary gear set <NUM> rotate together with the rotor <NUM> as a whole, so that the rotational force of the rotor <NUM> may be transmitted to the output shaft <NUM> in a <NUM>:<NUM> ratio. Accordingly, a washing mode and a dehydration mode may be implemented without a stop motion between the end of the washing and the start of the dehydration.

The planetary gear set <NUM> may include a sun gear <NUM>, a plurality of pinion gears <NUM>, a ring gear <NUM>, a connecting portion <NUM>, and a carrier <NUM>.

The sun gear <NUM> may be coupled to the rotor <NUM>. The sun gear <NUM> may be coupled to the rotor case <NUM> of the rotor <NUM>. The lower region of the sun gear <NUM> may be coupled to the radially inner region of the rotor case <NUM>. The sun gear <NUM> may be coupled to the plurality of pinion gears <NUM>. The upper region of the sun gear <NUM> may be coupled to the plurality of pinion gears <NUM>. The outer peripheral surface of the sun gear <NUM> may be coupled to the plurality of pinion gears <NUM>. The sun gear <NUM> may be bearing-coupled to the carrier <NUM> through a sun gear bearing <NUM>. A first gear <NUM> may be formed on the outer peripheral surface of the sun gear <NUM>. In one embodiment of the present disclosure, the first gear <NUM> is described as a spur gear, but the first gear <NUM> may be changed to a helical gear.

The plurality of pinion gears <NUM> may be spaced apart from each other in the circumferential direction. The outer peripheral surfaces of the plurality of pinion gears <NUM> may be coupled with the outer peripheral surfaces of the sun gear <NUM>, respectively. A second gear <NUM> may be formed on the outer peripheral surfaces of the plurality of pinion gears <NUM>. In one embodiment of the present disclosure, the second gear <NUM> is described as a spur gear, but alternatively, the second gear <NUM> may be changed to a helical gear.

In one embodiment of the present disclosure, the number of the plurality of pinion gears <NUM> is described as three, but is not limited thereto, and the number of the plurality of pinion gears <NUM> may be changed in various ways.

The connecting portion <NUM> may be formed inside each of the plurality of pinion gears <NUM>. The plurality of pinion gears <NUM> may be connected to the carrier <NUM> through the connecting portion <NUM>.

An inner peripheral surface of the ring gear <NUM> may be coupled with the plurality of pinion gears <NUM>. A third gear <NUM> may be formed on the inner peripheral surface of the ring gear <NUM>. In one embodiment of the present disclosure, the third gear <NUM> is described as a spur gear, but in other embodiments, the third gear <NUM> may be changed to a helical gear.

The outer peripheral surface of the ring gear <NUM> may be spline-coupled with the clutch actuators <NUM> and <NUM>. A third spline portion <NUM> may be formed on the outer peripheral surface of the ring gear <NUM>. The third spline portion <NUM> of the ring gear <NUM> may be spline-coupled with a fourth spline portion <NUM> of the clutch actuators <NUM> and <NUM>.

The carrier <NUM> may be coupled with the plurality of pinion gears <NUM>. The carrier <NUM> may be coupled with the plurality of pinion gears <NUM> through the connecting portion <NUM>. The carrier <NUM> may be arranged on the plurality of pinion gears <NUM>.

The carrier <NUM> may be spline-coupled to the outer peripheral surface of the output shaft <NUM>. A second spline portion <NUM> may be formed on the inner peripheral surface of the carrier <NUM>. The second spline portion <NUM> may be spline-coupled with the first spline portion <NUM> of the output shaft <NUM>.

The carrier <NUM> may be bearing-coupled with the sun gear <NUM> through the sun gear bearing <NUM>. The carrier <NUM> may be bearing-coupled with the ring gear <NUM> through the ring gear bearing <NUM>. Therefore, the rotational speed of the carrier <NUM> and the rotational speed of the ring gear <NUM> may be made different, and the rotational speed of the carrier <NUM> and the rotational speed of the sun gear <NUM> may be made different, so that the rotational force of the rotor <NUM> may be reduced by the gear ratio of n:<NUM> and transmitted to the output shaft <NUM>.

The ring gear bearing <NUM> may include a first ring gear bearing <NUM> and a second ring gear bearing <NUM> that are spaced apart in the vertical direction. The first ring gear bearing <NUM> may be arranged above the plurality of pinion gears <NUM>, and the second ring gear bearing <NUM> may be arranged below the plurality of pinion gears <NUM>.

The sun gear bearing <NUM> may overlap the first coil <NUM> and the second coil <NUM> in the direction vertical or horizontal to the output shaft <NUM>. The sun gear bearing <NUM> may include a first sun gear bearing <NUM> and a second sun gear bearing <NUM> that are spaced apart in a vertical direction. The vertical center regions of the plurality of pinion gears <NUM> may be arranged between the first coil <NUM> and the second coil <NUM> in a direction vertical or horizontal to the output shaft <NUM>. The plurality of pinion gears <NUM> may overlap the first coil <NUM> and the second coil <NUM> in the direction perpendicular or horizontal to the output shaft <NUM>. The plurality of pinion gears <NUM> may not overlap the third coil <NUM> in the direction perpendicular or horizontal to the output shaft <NUM>. The upper surface of the ring gear <NUM> may overlap the third coil <NUM> in the direction perpendicular or horizontal to the output shaft <NUM>. The lower surface of the ring gear <NUM> may be arranged below the first coil <NUM> in a direction perpendicular or horizontal to the output shaft <NUM>. Therefore, the size of the washing machine drive system <NUM> can be reduced.

The clutch <NUM> may be arranged between the motor <NUM> and <NUM> and the planetary gear set <NUM>. A portion of the clutch <NUM> may be spline-coupled to the planetary gear set <NUM>, and another portion may be coupled to the motor stator <NUM>. The clutch <NUM> may lock or unlock a portion of the planetary gear set <NUM>. Accordingly, the clutch <NUM> may allow the planetary gear set <NUM> to transmit the rotational force of the rotor <NUM> to the output shaft <NUM> at a <NUM>:<NUM> ratio, or to transmit the rotational force to the output shaft <NUM> while reducing the rotation force at a gear ratio of n:<NUM>. The clutch <NUM> may include the clutch stators <NUM>, <NUM>, <NUM>, and <NUM> and clutch actuators <NUM> and <NUM>.

The clutch stators <NUM>, <NUM>, <NUM>, and <NUM> may be coupled to the motor stator <NUM>. The clutch stators <NUM>, <NUM>, <NUM>, and <NUM> may be coupled to the motor couple portion <NUM>. The clutch stators <NUM>, <NUM>, <NUM>, and <NUM> may be coupled to the lower surface of the motor couple portion <NUM>. The clutch stators <NUM>, <NUM>, <NUM>, and <NUM> may be arranged between the planetary gear set <NUM> and the motor stator <NUM> in the direction perpendicular or horizontal to the output shaft <NUM>. The clutch stators <NUM>, <NUM>, <NUM>, and <NUM> may include a stator coupling portion <NUM>, a clutch stator <NUM>, an insulator <NUM>, and a coil <NUM>.

The stator coupling portion <NUM> may be coupled to the lower surface of the motor couple portion <NUM>. The clutch stator <NUM>, the insulator <NUM>, and the coil <NUM> may be coupled to the stator coupling portion <NUM>. The stator coupling portion <NUM> may be formed of a plastic material. The stator coupling portion <NUM> may include a circumferential portion <NUM> extending inwardly in a circumferential direction from an upper surface, and a second clutch portion <NUM> formed on a lower surface of the circumferential portion <NUM>.

The circumferential portion <NUM> may extend in a circumferential direction. The circumferential portion <NUM> may extend upwardly from the upper surface and inner peripheral surface of the stator coupling portion <NUM> and extend radially inwardly. The lower surface of the circumferential portion <NUM> may face the clutch actuators <NUM> and <NUM>.

The second clutch portion <NUM> may be vertically overlapped with the clutch actuators <NUM> and <NUM>. The second clutch portion <NUM> may face a first clutch portion <NUM> of the clutch actuators <NUM> and <NUM>. The second clutch portion <NUM> may be engaged and coupled with the first clutch portion <NUM> of the clutch actuators <NUM> and <NUM>. The second clutch portion <NUM> may be formed with a plurality of protrusions spaced apart from each other in the circumferential direction.

The clutch stator <NUM> may be coupled to the stator coupling portion <NUM>. The clutch stator <NUM> may be formed of a metal material. The insulator <NUM> and a coil <NUM> may be arranged in the clutch stator <NUM>. The clutch stator <NUM> may include first to third cores <NUM>, <NUM>, and <NUM> arranged in parallel in the vertical direction. The first to third cores <NUM>, <NUM>, and <NUM> may be formed in the same shape, respectively. First to third insulators <NUM>, <NUM>, and <NUM> and the first to third coils <NUM>, <NUM>, and <NUM> may be arranged in the first to third cores <NUM>, <NUM>, and <NUM>.

The insulator <NUM> may be arranged in the clutch stator <NUM>. The insulator <NUM> may include first to third insulators <NUM>, <NUM>, and <NUM> arranged in parallel in the vertical direction. The first to third insulators <NUM>, <NUM>, and <NUM> may be arranged in the first to third cores <NUM>, <NUM>, and <NUM>.

The coil <NUM> may be arranged in the clutch stator <NUM>. The coil <NUM> may be arranged radially inwardly of the insulator <NUM>. The coil <NUM> may include the first to third coils <NUM>, <NUM>, and <NUM>. The first to third coils <NUM>, <NUM>, and <NUM> may be arranged in parallel in the vertical direction. The first to third coils <NUM>, <NUM>, and <NUM> may be spaced apart from each other at equal intervals in the vertical direction. The first coil <NUM> may be arranged in the first core <NUM>. The second coil <NUM> may be arranged in the second core <NUM>. The third coil <NUM> may be arranged in the third core <NUM>. The first to third coils <NUM>, <NUM>, and <NUM> may each be formed in the same shape.

When current is supplied to the first coil <NUM>, the clutch actuators <NUM> and <NUM> may move downward. In this case, the third clutch portion <NUM> of the clutch actuators <NUM> and <NUM> is engaged and coupled with the fourth clutch portion <NUM> of the rotor <NUM> so that the clutch actuators <NUM> and <NUM> may be fixed to the rotor <NUM>. Since the planetary gear set <NUM> spline-coupled with the clutch actuators <NUM> and <NUM> rotates integrally with the rotor <NUM>, the rotational force of the rotor <NUM> may be transmitted <NUM>:<NUM> to the output shaft <NUM> to implement the dehydration mode.

When current is supplied to the third coil <NUM>, the clutch actuators <NUM> and <NUM> may move upward. In this case, the first clutch portion <NUM> of the clutch actuators <NUM> and <NUM> is engaged and coupled with the second clutch portion <NUM> of the clutch stators <NUM>, <NUM>, <NUM>, and <NUM> so that the clutch actuators <NUM> and <NUM> may be fixed to the clutch stators <NUM>, <NUM>, <NUM>, and <NUM>. Since the ring gear <NUM> of the planetary gear set <NUM> spline-coupled to the clutch actuators <NUM> and <NUM> is fixed, the rotational force of the rotor <NUM> may be reduced by a gear ratio of n:<NUM> and transmitted to the output shaft <NUM> to implement the washing mode.

When current is supplied to the second coil <NUM>, the clutch actuators <NUM> and <NUM> may be decoupled from the rotor <NUM> or the clutch stators <NUM>, <NUM>, <NUM>, and <NUM>. Accordingly, the neutral mode of the clutch <NUM> is implemented, so that the reduction ratio may be applied while maintaining the rotation of the rotor <NUM>. In addition, since the rotation of the rotor <NUM> is not stopped and the reduction ratio is applied to enter the initial dehydration mode, high torque may be generated.

The clutch actuators <NUM> and <NUM> may be spline-coupled to the outer peripheral surface of the planetary gear set <NUM>. Accordingly, the clutch actuators <NUM> and <NUM> may move in the vertical direction in a state of being coupled to the planetary gear set <NUM>. The clutch actuators <NUM> and <NUM> may face the clutch stators <NUM>, <NUM>, <NUM>, and <NUM>. The clutch actuators <NUM> and <NUM> may be arranged between the planetary gear set <NUM> and the motor stator <NUM> in the direction perpendicular or horizontal to the output shaft <NUM>. The clutch actuators <NUM> and <NUM> may include a clutch coupling portion <NUM>, a first clutch portion <NUM>, a third clutch portion <NUM>, a fourth spline portion <NUM>, and a clutch magnet <NUM>.

The clutch coupling portion <NUM> may extend in the circumferential direction. The cross section of the clutch coupling portion <NUM> may be formed in a "U" shape. The clutch coupling portion <NUM> may be spline-coupled to the planetary gear set <NUM>. The clutch coupling portion <NUM> may be spline-coupled to the ring gear <NUM> of the planetary gear set <NUM>. The clutch coupling portion <NUM> may face the clutch stators <NUM>, <NUM>, <NUM>, and <NUM>. The upper surface of the clutch coupling portion <NUM> may face the second clutch portion <NUM>. The lower surface of the clutch coupling portion <NUM> may face the fourth clutch portion <NUM>.

The first clutch portion <NUM> may be formed on the upper surface of the clutch actuators <NUM> and <NUM>. The first clutch portion <NUM> may be formed on the upper surface of the clutch coupling portion <NUM>. The first clutch portion <NUM> may be formed in a plurality of protrusion shapes spaced apart in the circumferential direction. The first clutch portion <NUM> may face the second clutch portion <NUM>. The first clutch portion <NUM> may be engaged and coupled with the second clutch portion <NUM>. Specifically, when current is supplied to the third coil <NUM> and the clutch actuators <NUM> and <NUM> moves upward, the first clutch portion <NUM> may be engaged and coupled with the second clutch portion <NUM> so that the clutch actuators <NUM> and <NUM> may be fixed to the clutch stators <NUM>, <NUM>, <NUM>, and <NUM>. Accordingly, by coupling the clutch actuators <NUM> and <NUM> to the clutch stators <NUM>, <NUM>, <NUM>, and <NUM>, the rotation of the ring gear <NUM> spline-coupled with the clutch actuators <NUM> and <NUM> may be stopped.

The third clutch portion <NUM> may be formed on the lower surface of the clutch actuators <NUM> and <NUM>. The third clutch portion <NUM> may be formed on the lower surface of the clutch coupling portion <NUM>. The third clutch portion <NUM> may be formed as a plurality of protrusion shapes spaced apart in the circumferential direction. The third clutch portion <NUM> may face the fourth clutch portion <NUM>. The third clutch portion <NUM> may be engaged and coupled with the fourth clutch portion <NUM>. Specifically, when current is supplied to the first coil <NUM> and the clutch actuators <NUM> and <NUM> moves downward, the third clutch portion <NUM> may be engaged and coupled with the fourth clutch portion <NUM>, so that the clutch actuators <NUM> and <NUM> may be fixed to the rotor <NUM>. Therefore, the ring gear <NUM> spline-coupled with the clutch actuators <NUM> and <NUM> may be rotated together with the rotor <NUM>.

The fourth spline portion <NUM> may be formed on the inner peripheral surface of the clutch coupling portion <NUM>. The fourth spline portion <NUM> may be spline-coupled with the planetary gear set <NUM>. The fourth spline portion <NUM> may be spline-coupled with the third spline portion <NUM> of the ring gear <NUM>.

The clutch magnet <NUM> may be arranged in the clutch coupling portion <NUM>. The clutch magnet <NUM> may be arranged in a groove formed on the outer peripheral surface of the clutch coupling portion <NUM>. The clutch magnet <NUM> may extend in the circumferential direction. The clutch magnet <NUM> may face the clutch stators <NUM>, <NUM>, <NUM>, and <NUM>. The clutch magnet <NUM> may face the first to third coils <NUM>, <NUM>, and <NUM>. The clutch magnet <NUM> may move in the vertical direction by electromagnetic interaction with the first to third coils <NUM>, <NUM>, and <NUM>. The clutch magnet <NUM> may include a plurality of magnetic poles arranged in the vertical direction. The vertical length of the clutch magnet <NUM> may be between <NUM> and <NUM> times the vertical length of each of the first to third coils <NUM>, <NUM>, and <NUM>. Preferably, the vertical length of the clutch magnet <NUM> may be between <NUM> and <NUM> times the vertical length of each of the first to third coils <NUM>, <NUM>, and <NUM>. More preferably, the vertical length of the clutch magnet <NUM> may be twice the vertical length of each of the first to third coils <NUM>, <NUM>, and <NUM>. Accordingly, while the positions of the three stable points can be stably determined, the efficiency of the clutch <NUM> can be improved. Here, the vertical length of the clutch magnet <NUM> may be understood to mean the length in the up-down direction based on <FIG>, <FIG>, <FIG>.

When current is supplied to the first coil <NUM>, the clutch magnet <NUM> may overlap the first coil <NUM>, the second coil <NUM>, the first core <NUM>, and the second core <NUM> in the horizontal direction. When current is supplied to the first coil <NUM>, the vertical center region of the clutch magnet <NUM> may be overlap the upper region of the first coil <NUM> in the horizontal direction. Here, the upper region of the first coil <NUM> may be interpreted as meaning a region adjacent to the upper end or the upper surface of the first coil <NUM>. In the present disclosure, the meaning of overlapping in the horizontal direction may be understood as overlapping in a left-right direction based on <FIG>, <FIG>, <FIG>.

When current is supplied to the second coil <NUM>, the clutch magnet <NUM> may overlap the second coil <NUM> and the first to third cores <NUM>, <NUM>, and <NUM> in the horizontal direction. When current is supplied to the second coil <NUM>, the vertical center region of the clutch magnet <NUM> may overlap the vertical center region of the second coil <NUM> in the horizontal direction.

When current is supplied to the third coil <NUM>, the clutch magnet <NUM> may overlap the second coil <NUM>, the third coil <NUM>, the second core <NUM>, and the third core <NUM> in the horizontal direction. When current is supplied to the third coil <NUM>, the vertical center region of the clutch magnet <NUM> may overlap the lower region of the third coil <NUM> in the horizontal direction. Here, the lower region of the third coil <NUM> may be interpreted as a region adjacent to the lower end or the lower surface of the third coil <NUM>.

Accordingly, three stable points may be formed so that the position of the clutch actuators <NUM> and <NUM> may be maintained even when the supply of current to the first to third coils <NUM>, <NUM>, and <NUM> is stopped. Here, the three stable points may be understood as the central region of the clutch magnet <NUM> being located at the -k, <NUM>, and k points based on <FIG>.

Specifically, when the supply of current is stopped after the supply of current to the first coil <NUM>, the coupling of the clutch actuators <NUM> and <NUM> and the rotor <NUM> may be maintained. When the current supply to the third coil <NUM> is stopped after the current supply is supplied, the coupling between the clutch actuators <NUM> and <NUM> and the clutch stators <NUM>, <NUM>, <NUM>, and <NUM> may be maintained. When the current supply to the second coil <NUM> is stopped after the current supply is supplied, the decoupling between the clutch actuators <NUM> and <NUM> and the rotor <NUM> or the clutch stators <NUM>, <NUM>, <NUM>, and <NUM> may be maintained.

Accordingly, even when the clutch actuators <NUM> and <NUM> is moved in the vertical direction and the current supply is stopped, the position of the clutch actuators <NUM> and <NUM> is maintained, so that power consumption may be reduced.

<FIG> are operation diagrams of the clutch actuator in the washing machine drive system according to one embodiment of the present disclosure.

Referring to <FIG>, when current is supplied to the first coil <NUM>, the clutch actuators <NUM> and <NUM> moves downward due to the electromagnetic interaction between the first coil <NUM> and the clutch magnet <NUM>. In this case, the third clutch portion <NUM> of the clutch actuators <NUM> and <NUM> is engaged and coupled with the fourth clutch portion <NUM> of the rotor <NUM>. Since the ring gear <NUM> spline-coupled with the clutch actuators <NUM> and <NUM> rotate together with the rotor <NUM>, the clutch <NUM> transmits the rotational force of the rotor <NUM> to the output shaft <NUM><NUM>:<NUM> to implement the dehydration mode.

Referring to <FIG>, when current is supplied to the second coil <NUM>, the clutch actuators <NUM> and <NUM> moves to the region adjacent to the second coil <NUM> due to the electromagnetic interaction between the second coil <NUM> and the clutch magnet <NUM>. In this case, the clutch actuators <NUM> and <NUM> are decoupled with the rotor <NUM> and the clutch stators <NUM>, <NUM>, <NUM>, and <NUM> and implements the neutral mode, so that even when the rotor <NUM> rotates, the mode can be switched from the washing mode to the dehydration mode or from the dehydration mode to the washing mode.

Referring to <FIG>, when current is supplied to the third coil <NUM>, the clutch actuators <NUM> and <NUM> moves upward due to the electromagnetic interaction between the third coil <NUM> and the clutch magnet <NUM>. In this case, the first clutch portion <NUM> of the clutch actuators <NUM> and <NUM> is engaged and coupled with the second clutch portion <NUM> of the clutch stators <NUM>, <NUM>, <NUM>, and <NUM>. Since the ring gear <NUM> splined-coupled with the clutch actuators <NUM> and <NUM> is fixed, the planetary gear set <NUM> reduces the rotational force of the rotor <NUM> with a gear ratio of n:<NUM> and transmits the reduced rotational force to the output shaft <NUM> to implement the washing mode.

<FIG> is a graph illustrating a z-axis force according to the position of the clutch actuator of the washing machine drive system according to one embodiment of the present disclosure. <FIG> are views illustrating a magnetic flux density distribution of the clutch stator according to the position of the clutch actuator of the washing machine drive system according to one embodiment of the present disclosure.

Referring to <FIG> and <FIG>, it can be seen that when the vertical center region of the clutch magnet <NUM> is arranged at a -k position, the z-axis force applied to the clutch magnet <NUM> by the magnetic flux density of the first to third cores <NUM>, <NUM>, and <NUM> and the clutch magnet <NUM> is <NUM>.

Referring to <FIG> and <FIG>, it can be seen that when the vertical center region of the clutch magnet <NUM> is arranged at an O position, the z-axis force applied to the clutch magnet <NUM> by the magnetic flux density of the first to third cores <NUM>, <NUM>, and <NUM> and the clutch magnet <NUM> is <NUM>.

Referring to <FIG> and <FIG>, when the vertical center region of the clutch magnet <NUM> is arranged at a +k position, it can be seen that the z-axis force applied to the clutch magnet <NUM> by the magnetic flux density of the first to third cores <NUM>, <NUM>, and <NUM> and the clutch magnet <NUM> is <NUM>.

<FIG> and <FIG> are graphs illustrating the z-axis force applied to the clutch magnet according to the position of the clutch magnet of the washing machine drive system according to one embodiment of the present disclosure.

Referring to <FIG> and <FIG>, when the mode is switched from Mode <NUM> to Mode <NUM>, current is supplied to the second coil <NUM>. Specifically, when current is supplied to the second coil <NUM> in the dehydration mode where the clutch magnet <NUM> is on the left side in the z-axis direction vertically downward, force is applied to the clutch magnet <NUM> to the right side in the z-axis direction. In this case, since the position of the clutch magnet <NUM> moves to the center in the z-axis direction (center in the vertical direction), the neutral mode can be implemented. In particular, when the position of the z-axis center area (center area in the vertical direction) of the clutch magnet <NUM> is at a position of <NUM>, the z-axis force applied to the clutch magnet <NUM> becomes <NUM>, so that it can be positioned at a stable point without immediately switching to the washing mode.

Referring to <FIG> and <FIG>, when the mode is switched from Mode <NUM> to Mode <NUM>, current is supplied to the first coil <NUM>. Specifically, when current is supplied to the first coil <NUM> in the neutral mode where the clutch magnet <NUM> is at the center of the z-axis direction (center in the vertical direction), a force is applied to the clutch magnet <NUM> to the left in the z-axis direction. In this case, since the position of the clutch magnet <NUM> moves to the left in the z-axis direction (downward in the vertical direction), the dehydration mode can be implemented.

Referring to <FIG> and <FIG>, when the mode is switched from Mode <NUM> to Mode <NUM>, current is supplied to the third coil <NUM>. Specifically, when current is supplied to the third coil <NUM> in the neutral mode where the clutch magnet <NUM> is at the center of the z-axis direction (the center in the vertical direction), a force is applied to the clutch magnet <NUM> to the right in the z-axis direction. In this case, since the position of the clutch magnet <NUM> moves to the right in the z-axis direction (upward in the vertical direction), the washing mode can be implemented.

Referring to <FIG> and <FIG>, when the mode is switched Mode <NUM> to Mode <NUM>, current is supplied to the second coil <NUM>. Specifically, when current is supplied to the second coil <NUM> in the washing mode where the clutch magnet <NUM> is to the right in the z-axis direction (upward in the vertical direction), a force is applied to the clutch magnet <NUM> to the left in the z-axis direction. In this case, since the position of the clutch magnet <NUM> moves to the left in the z-axis direction (downward in the vertical direction), the neutral mode can be implemented. In particular, when the position of the z-axis central region (central region in the vertical direction) of the clutch magnet <NUM> is at a position of <NUM>, the z-axis force applied to the clutch magnet <NUM> becomes <NUM>, so that the mode does not immediately go to the dehydration mode but can be positioned at a stable point.

That is, the size and arrangement of the detailed configuration of the clutch <NUM> according to one embodiment of the present disclosure can form three stable points, and thus, even when the supply of current to the first to third coils <NUM>, <NUM>, and <NUM> is stopped, the positions of the clutch actuators <NUM> and <NUM> can be maintained.

Claim 1:
A washing machine drive system comprising:
a housing (<NUM>);
a motor stator (<NUM>) coupled to the housing (<NUM>);
a rotor (<NUM>) facing the motor stator (<NUM>);
an output shaft (<NUM>) bearing-coupled to the housing (<NUM>);
a planetary gear set (<NUM>) coupled to the rotor (<NUM>) and spline-coupled to an outer peripheral surface of the output shaft (<NUM>);
a clutch stator (<NUM>, <NUM>, <NUM>) coupled to the motor stator (<NUM>); and
a clutch actuator (<NUM>, <NUM>) spline-coupled to an outer peripheral surface of the planetary gear set (<NUM>) so as to be vertically movable and facing the clutch stator (<NUM>, <NUM>, <NUM>),
characterised in that
the clutch stator (<NUM>, <NUM>, <NUM>) includes first to third coils (<NUM>, <NUM>, <NUM>) arranged in parallel in a vertical direction, the vertical direction being parallel to the output shaft (<NUM>);
the clutch actuator (<NUM>, <NUM>) is configured to be fixed to the rotor (<NUM>) and to transmit rotational force of the rotor (<NUM>) to the output shaft (<NUM>) at a <NUM>:<NUM> ratio when current is supplied to the first coil (<NUM>),
the clutch actuator (<NUM>, <NUM>) is configured to be fixed to the clutch stator (<NUM>, <NUM>, <NUM>), to reduce the rotational force of the rotor (<NUM>) at a gear ratio of n:<NUM>, and to transmit the reduced rotational force to the output shaft (<NUM>) when current is supplied to the third coil (<NUM>), and
the clutch actuator (<NUM>, <NUM>) is configured to be disengaged from the rotor (<NUM>) or the clutch stator (<NUM>, <NUM>, <NUM>) when current is supplied to the second coil (<NUM>).