Patent Description:
The washing machine is driven in two main operating modes (washing mode and spin-drying mode) with different operating conditions.

Therefore, 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 at low speed and high torque with a gear ratio of n: <NUM> (washing mode), or operates the output shaft at high speed and low torque with a gear ratio of <NUM>:<NUM> (spin-drying mode).

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

That is, in a normal washing machine, after the washing mode or the rinsing mode is ended, the motor is temporarily stopped, and a draining operation is performed. And, after the draining operation ends, a spin-drying initial mode starts.

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

In addition, in order to start the spin-drying mode after the spin-drying initial mode is completed, the output shaft must be operated at high speed and low torque.

Therefore, the drive system of the washing machine includes parts for shifting a rotational force of the rotor shaft transmitted to the output shaft between the spin-drying initial mode and the spin-drying mode, for example, a planetary gear set and a clutch.

As an example of a related art related to the present invention, Korean Patent Publication No. <CIT> (hereinafter referred to as "Related Art <NUM>") discloses a structure for changing a gear ratio by installing a planetary gear set including carriers, sun gears, multiple satellite gears, internal gears, etc. in a rotor case and changing the position of the internal gear by a solenoid clutch.

That is, in the case of Related Art <NUM>, the washing machine is operated at low speed and high torque by allowing the internal gear to be supported by the stator through the slider of the solenoid clutch in the spin-drying initial mode, and by allowing rotations of the rotor shaft and the sun gear to be transmitted to the output shaft through the planetary gear set.

In addition, the washing machine is operated at high speed and low torque by allowing the internal gear to be supported on the rotor shaft through the slider of the solenoid clutch in the spin-drying mode, and by allowing rotations of the rotor shaft and the sun gear to be transmitted to the output shaft without going through the planetary gear set.

However, according to the drive system disclosed in Related Art <NUM>, since a larger coil is required to obtain sufficient electromagnetic force to move the solenoid clutch, there is a problem in that the weight and volume of the solenoid clutch increases.

In addition, since the solenoid clutch is positioned behind the rotor and the stator, it is disadvantageous to secure the volume of the washing machine, and in order to apply power to the solenoid clutch, a separate circuit must be configured and wired between the rotor and the stator, so that there are problems such as difficult wiring work.

As another example of a related art related to present invention, Korean Patent Registration Publication No. <CIT> (hereinafter referred to as "Related Art <NUM>") discloses a structure for changing a gear ratio while moving the position of a deceleration coupling unit including the planetary gear set forward and backward using a lever.

That is, in the case of Related Art <NUM>, in the spin-drying initial mode, the deceleration coupling unit is moved forward according to the operation of the lever of the lever unit, and accordingly, teeth formed on the coupling cap of the deceleration coupling unit are engaged with teeth formed on the drum, so that the washing machine is operated at low speed and high torque.

In the spin-drying mode, the deceleration coupling unit is moved backward according to the operation of the lever of the lever unit, and accordingly, teeth formed on the coupling housing of the deceleration coupling unit are engaged with teeth formed on the rotor housing, so that the washing machine is operated at high speed and low torque.

However, according to the driving system disclosed in Related Art <NUM>, since the pinion gear provided in the carrier of the deceleration coupling unit must move in the axial direction with respect to the sun gear, only the spur gear, not helical gears, can be used as the pinion gear and the sun gear, and there is a problem in that noise is generated due to this.

In addition, since the forward and backward movement of the deceleration coupling unit is possible only while the motor is stopped, there is a problem in that the motor must be stopped for mode conversion.

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

Therefore, in the spin-drying initial mode, the planetary gear set serves as a support point, so that the output shaft is supported by the planetary gear set and the bearing, but in the spin-drying mode, since the rotor, the planetary gear set, and the output shaft operate as one, and the output shaft is supported by only one bearing, there is a problem of low durability in the spin-drying mode operating at high speed and low torque. <CIT> discloses a direct driving apparatus for a washing machine according to the present invention, capable of deceleration driving, includes a tub, a stator assembly coupled to the tub and a rotor assembly positioned outside the stator assembly, wherein the apparatus further includes a deceleration coupling unit positioned in a central space of the stator assembly.

A problem to be solved by the present invention is to provide a drive system of a washing machine capable of implementing a washing mode and a spin-drying mode by moving the entire planetary gear set without a stop operation between ending washing and starting spin-drying.

In addition, a problem to be solved by the present invention is to provide a drive system of a washing machine capable of implementing low-speed and high-torque washing mode of n:<NUM> since the rotation of the ring gear is stopped without additional parts.

In addition, a problem to be solved by the present invention is to provide a drive system of a washing machine capable of stably guiding the movement of the planetary gear set with respect to the output shaft.

In addition, a problem to be solved by the present invention is to provide a drive system of a washing machine capable of implementing high-speed and low-torque spin-drying mode of <NUM>:<NUM> since the plurality of pinion gears and the rotor shaft are synchronized.

In addition, a problem to be solved by the present invention is to provide a drive system of a washing machine capable of stably guiding the movement of the planetary gear set with respect to the rotor shaft.

In addition, a problem to be solved by the present invention is to provide a drive system of a washing machine capable of increasing the safety factor of the gears provided in the planetary gear set, and reducing the noise generated during gear rotation.

In addition, a problem to be solved by the present invention is to provide a drive system of a washing machine capable of increasing the space efficiency of the washing machine since the length in the axial direction can be reduced.

In addition, a problem to be solved by the present invention is to provide a drive system of a washing machine capable of preventing parts from being damaged when the rotational speeds of the rotor shaft and the output shaft are different.

In addition, a problem to be solved by the present invention is to provide a drive system of a washing machine capable of moving the entire planetary gear set while improving space efficiency.

In addition, a problem to be solved by the present invention is to provide a drive system of a washing machine capable of improving rotational stability of the output shaft since two bearings support the output shaft connected to the washing machine tub.

A drive system of a washing machine according to one aspect of the present invention for achieving the above object is specified in independent claim <NUM>.

In this case, when the planetary gear set is moved to one side, a part of the planetary gear set may be coupled to the rotor shaft to transmit a rotational force of the rotor shaft to the output shaft at a ratio of <NUM>:<NUM>, and when the planetary gear set is moved to other side, another part of the planetary gear set may be coupled to the housing to reduce and transmit the rotational force of the rotor shaft to the output shaft at a gear ratio of n:<NUM>.

Through this, it is possible to implement a washing mode and a spin-drying mode by moving the entire planetary gear set without a stop operation between ending washing and starting spin-drying.

In addition, the planetary gear set may include a sun gear spline-coupled to the rotor shaft, a plurality of pinion gears coupled to an outer circumferential surface of the sun gear and spaced apart in a circumferential direction, a ring gear that an inner circumferential surface of the ring gear coupled to the plurality of pinion gears, and a carrier coupled to the plurality of pinion gears.

In this case, the ring gear may include a first clutch portion formed on an upper surface of the ring gear, and the housing may include a second clutch portion coupled to the first clutch portion when the planetary gear set is moved to the other side.

Through this, since the rotation of the ring gear is stopped without additional parts, it is possible to implement low-speed and high-torque washing mode of n: <NUM>.

In addition, the carrier may include a first carrier disposed on the plurality of pinion gears, a second carrier disposed under the plurality of pinion gears, and a plurality of connecting portions connecting each of the plurality of pinion gears to the first carrier and the second carrier.

In this case, the first carrier may include a first spline portion formed on an inner circumferential surface of the first carrier, and the output shaft may include a second spline portion formed on an outer circumferential surface of the output shaft and spline-coupled to the first spline portion.

Through this, it is possible to stably guide the movement of the planetary gear set with respect to the output shaft.

In addition, the second carrier may include a third clutch portion formed on a lower surface of the second carrier, and the rotor shaft may include a fourth clutch portion coupled to the third clutch portion when the planetary gear set is moved to the one side.

Through this, since the plurality of pinion gears and the rotor shaft are synchronized, it is possible to implement high-speed and low-torque spin-drying mode of <NUM>:<NUM>.

In addition, the sun gear may include a third spline portion formed on an inner circumferential surface of the sun gear, and the rotor shaft may include a fourth spline portion formed on an outer circumferential surface of the rotor shaft and spline-connected to the third spline portion.

Through this, it is possible to stably guide the movement of the planetary gear set with respect to the rotor shaft.

In addition, the sun gear, the plurality of pinion gears, and the ring gear may include helical gears.

Through this, it is possible to increase the safety factor of the gears provided in the planetary gear set, and reduce the noise generated during gear rotation.

Through this, since the length in the axial direction can be reduced, it is possible to increase the space efficiency of the washing machine.

In addition, the present invention may further include a bushing disposed between the at least part of the output shaft and the rotor shaft.

Through this, it is possible to prevent parts from being damaged when the rotational speeds of the rotor shaft and the output shaft are different.

In addition, the ring gear may include a groove formed on an outer circumferential surface of the ring gear, and wherein the actuator is disposed on the groove.

Through this, it is possible to move the entire planetary gear set while improving space efficiency.

A drive system of a washing machine according to one aspect of the present invention (not being claimed) for achieving the above object includes a housing, a motor disposed on one side of the housing, a rotor coupled to the motor, an output shaft bearing-coupled to the housing, and wherein at least part of the output shaft is disposed within the rotor, a planetary gear set that a part of the planetary gear set is spline-coupled to the rotor, and other part of the planetary gear set is spline-coupled to the output shaft, and an actuator moving the planetary gear set in a vertical direction.

In this case, when the planetary gear set is moved to one side, a part of the planetary gear set may be coupled to the rotor to transmit a rotational force of the rotor to the output shaft at a ratio of <NUM>:<NUM>, and when the planetary gear set is moved to other side, another part of the planetary gear set may be coupled to the housing to reduce and transmit the rotational force of the rotor to the output shaft at a gear ratio of n: <NUM>.

In addition, the planetary gear set may include a sun gear spline-coupled to the rotor, a plurality of pinion gears coupled to an outer circumferential surface of the sun gear and spaced apart in a circumferential direction, a ring gear that an inner circumferential surface of the ring gear coupled to the plurality of pinion gears, and a carrier coupled to the plurality of pinion gears.

In this case, the ring gear may include a fifth clutch portion formed on an upper surface of the ring gear, and the housing may include a sixth clutch portion coupled to the fifth clutch portion when the planetary gear set is moved to the other side.

In addition, the carrier may include a third carrier disposed on the plurality of pinion gears, a fourth carrier disposed under the plurality of pinion gears, and a plurality of connecting portions connecting each of the plurality of pinion gears to the third carrier and the fourth carrier.

In this case, the third carrier may include a fifth spline portion formed on an outer circumferential surface of the third carrier, and the output shaft may include a first region disposed in the planetary gear set, a second region disposed on the first region, a protrusion protruding downward from a lower surface of the second region and spaced apart from the first region, and a sixth spline portion formed on an inner circumferential surface of the protrusion and spline-coupled to the fifth spline portion.

In addition, the present invention may further include a third bearing disposed between the second region and the housing, and a fourth bearing disposed between the protrusion and the housing,.

In this case, the planetary gear set may be disposed under the fourth bearing.

Through this, since two bearings support the output shaft connected to the washing machine tub, it is possible to improve rotational stability of the output shaft.

In addition, the ring gear may include a seventh clutch portion formed on a lower surface of the ring gear, and the rotor may include an eighth clutch portion coupled to the seventh clutch portion when the planetary gear set is moved to the one side.

Through this, since the ring gear and the rotor are synchronized, it is possible to implement high-speed and low-torque spin-drying mode of <NUM>:<NUM>.

In addition, the sun gear may include a seventh spline portion formed on an outer circumferential surface of the sun gear, and the rotor may include an eighth spline portion formed on an inner circumferential surface of the rotor and spline-connected to the seventh spline portion.

Through this, it is possible to stably guide the movement of the planetary gear set with respect to the rotor.

Through the present invention, it is possible to provide the drive system of the washing machine capable of implementing a washing mode and a spin-drying mode by moving the entire planetary gear set without a stop operation between ending washing and starting spin-drying.

In addition, through the present invention, since the rotation of the ring gear is stopped without additional parts, it is possible to provide the drive system of the washing machine capable of implementing low-speed and high-torque washing mode of n:<NUM>.

Through the present invention, it is possible to provide the drive system of the washing machine capable of stably guiding the movement of the planetary gear set with respect to the output shaft.

In addition, through the present invention, since the plurality of pinion gears and the rotor shaft are synchronized, it is possible to provide the drive system of the washing machine capable of implementing high-speed and low-torque spin-drying mode of <NUM>:<NUM>.

In addition, through the present invention, it is possible to provide the drive system of the washing machine capable of stably guiding the movement of the planetary gear set with respect to the rotor shaft.

In addition, through the present invention, it is possible to provide the drive system of the washing machine capable of increasing the safety factor of the gears provided in the planetary gear set, and reducing the noise generated during gear rotation.

In addition, through the present invention, since the length in the axial direction can be reduced, it is possible to provide the drive system of the washing machine capable of increasing the space efficiency of the washing machine.

In addition, through the present invention, it is possible to provide the drive system of the washing machine capable of preventing parts from being damaged when the rotational speeds of the rotor shaft and the output shaft are different.

In addition, through the present invention, it is possible to provide the drive system of the washing machine capable of moving the entire planetary gear set while improving space efficiency.

In addition, through the present invention, it is possible to provide the drive system of the washing machine capable of improving rotational stability of the output shaft since two bearings support the output shaft connected to the washing machine tub.

Hereinafter, embodiments disclosed in the present invention will be described in detail with reference to the accompanying drawings, however, regardless of the reference numerals, the same or similar components will be given the same reference numerals and redundant description thereof will be omitted.

In describing the embodiments disclosed in the present invention, when a component is referred to as being "connected" or "accessed" to other component, it may be directly connected or accessed to the other component, however, it may be understood that other components may be present in the middle.

In addition, in describing the embodiments disclosed in the present invention, when it is determined that the detailed description of the related known technology may obscure the subject matter of the embodiments disclosed in the present invention, the detailed description thereof will be omitted. In addition, the accompanying drawings are only for easily understanding the embodiments disclosed in the present invention.

On the other hand, terms of invention may be replaced with terms such as document, specification, description.

<FIG> and <FIG> are perspective views of a tub of a washing machine and a drive system of a washing machine according to an embodiment of the present invention. <FIG> is a perspective view of a drive system of a washing machine according to an embodiment of the present invention. <FIG> is an exploded perspective view of a drive system of a washing machine according to an embodiment of the present invention. <FIG> is a cross-sectional view of a drive system of a washing machine according to an embodiment of the present invention. <FIG> is a perspective view of a planetary gear set of a drive system of a washing machine according to an embodiment of the present invention. <FIG> is a perspective view of an output shaft of a drive system of a washing machine according to an embodiment of the present invention. <FIG> is a view in which the first carrier is removed from <FIG>. <FIG> is a perspective view of a planetary gear set of a drive system of a washing machine according to an embodiment of the present invention. <FIG> is a cross-sectional perspective view of a housing of a drive system of a washing machine according to an embodiment of the present invention. <FIG> is a perspective view of a rotor shaft of a drive system of a washing machine according to an embodiment of the present invention.

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

The washing machine according to an embodiment of the present invention may be a top loading type in which the center of rotation of the inner tub is formed in a direction perpendicular to the floor and it is designed for the laundry to be loaded from the top and a front loading type in which the center of rotation of the inner tub is formed in a direction horizontal to the floor or it is inclined in a downward direction toward the rear end and it is designed for the laundry to be loaded from the front.

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

The drive system of the washing machine <NUM> according to an embodiment of the present invention includes a housing <NUM>, an output shaft <NUM>, a first bearing <NUM>, a second bearing <NUM>, and a planetary gear set <NUM>, an actuator <NUM>, a rotor shaft <NUM>, and a motor <NUM>.

The output shaft <NUM> may be rotatably disposed in the housing <NUM>. The pulsator <NUM> may be disposed above the housing <NUM>. The housing <NUM> may be coupled to the inner tub <NUM>. The motor <NUM> may be disposed below the housing <NUM>. The housing <NUM> may be coupled to the planetary gear set <NUM>.

The housing <NUM> may include a second clutch portion <NUM>. The second clutch portion <NUM> may protrude inward from an inner circumferential surface of the housing <NUM> and protrude downward from a circumferential portion <NUM> extending in a circumferential direction. The second clutch portion <NUM> may engage with a first clutch portion <NUM> of a ring gear <NUM> of the planetary gear set <NUM> when the planetary gear set <NUM> is moved to the top or the other side. The second clutch portion <NUM> may be formed in a shape complementary to that of the first clutch portion <NUM>.

The output shaft <NUM> may extend in the axial direction. The output shaft <NUM> may be coupled to 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 rotatably coupled to the rotor shaft <NUM> at the same speed or at different speeds. The output shaft <NUM> may be bushing-coupled to the rotor shaft <NUM>.

The pulsator <NUM> may be coupled to an upper region <NUM> of the output shaft <NUM>.

A central region <NUM> of the output shaft <NUM> may be bearing-coupled to the housing <NUM>. The first bearing <NUM> may be disposed between the central region <NUM> of the output shaft <NUM> and the housing <NUM>.

A lower region <NUM> of the output shaft <NUM> may be disposed within the rotor shaft <NUM>. The lower region <NUM> of the output shaft <NUM> may be coupled to the rotor shaft <NUM>. The bushing <NUM> may be disposed between the lower region <NUM> of the output shaft <NUM> and the rotor shaft <NUM>. A diameter of the lower region <NUM> of the output shaft <NUM> may be smaller than a diameter of the central region <NUM>. An axial length of the lower region <NUM> of the output shaft <NUM> may be longer than an axial length of the central region <NUM> of the output shaft <NUM>. In one embodiment of the present invention, the axial direction may be interpreted as meaning a vertical direction based on <FIG>.

The output shaft <NUM> may include a second spline portion <NUM> formed on an outer circumferential surface. The second spline portion <NUM> may protrude outward from the outer circumferential surface of the output shaft <NUM>. The second spline portion <NUM> may be disposed between the central region <NUM> and the lower region <NUM> of the output shaft <NUM>. The second spline portion <NUM> may be spline-coupled to a first spline portion <NUM> of a first carrier <NUM> of the planetary gear set <NUM>. Here, "a spline" may mean a cut groove on a shaft or a bore, and "a spline coupling" may mean a coupling so that perturbation in the axial direction is possible and rotation together is possible.

The first bearing <NUM> may be disposed between the housing <NUM> and the output shaft <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 disposed below a fifth bearing <NUM>. The first bearing <NUM> may be disposed above the planetary gear set <NUM>.

The second bearing <NUM> may be disposed between the rotor shaft <NUM> and the housing <NUM>. The second bearing <NUM> may be disposed below the planetary gear set <NUM>. The second bearing <NUM> may bearing-couple the rotor shaft <NUM> to the housing <NUM>. The second bearing <NUM> may rotatably couple the rotor shaft <NUM> to the housing <NUM>. The second bearing <NUM> may extend in the circumferential direction.

A part of the planetary gear set <NUM> may be spline-coupled to the rotor shaft <NUM>, and another part may be spline-coupled to the output shaft <NUM>. The planetary gear set <NUM> may be vertically moved by a first actuator <NUM>.

When the planetary gear set <NUM> is moved to one side or lower part, a part of the planetary gear set <NUM> may be coupled to the rotor shaft <NUM>. In this case, the rotational force of the rotor shaft <NUM> may be transmitted to the output shaft <NUM> at a <NUM>:<NUM> ratio.

When the planetary gear set <NUM> is moved to the other side or upper part, another part of the planetary gear set <NUM> may be coupled to the housing <NUM>. In this case, the rotational force of the rotor shaft <NUM> may be reduced at a gear ratio of n:<NUM> and transmitted to the output shaft <NUM>.

Through this, it is possible to implement a washing mode and a spin-drying mode by moving the entire planetary gear set <NUM> without a stop operation between ending washing and starting spin-drying.

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

The sun gear <NUM> may be spline-coupled to the rotor shaft <NUM>. Specifically, a third spline portion <NUM> formed on an inner circumferential surface of the sun gear <NUM> may be spline-coupled to a fourth spline portion <NUM> formed on an outer circumferential surface of the rotor shaft <NUM>. A first helical gear <NUM> may be formed on an outer circumferential surface of the sun gear <NUM>.

The plurality of pinion gears <NUM> may be spaced apart from each other in the circumferential direction. Outer circumferential surfaces of the plurality of pinion gears <NUM> may be coupled to the outer circumferential surfaces of the sun gear <NUM>, respectively. A second helical gear <NUM> may be formed on the outer circumferential surfaces of the plurality of pinion gears <NUM>.

In one embodiment of the present invention, the number of the plurality of pinion gears <NUM> is four as an example, but the number of the plurality of pinion gears <NUM> may be variously changed without being limited thereto.

A plurality of connection portions <NUM> may be formed inside each of the plurality of pinion gears <NUM>. The plurality of pinion gears <NUM> may be connected to the carriers <NUM> and <NUM> through the connection portion <NUM>.

An inner circumferential surface of the ring gear <NUM> may be coupled to the plurality of pinion gears <NUM>. A third helical gear <NUM> may be formed on the inner circumferential surface of the ring gear <NUM>.

The ring gear <NUM> may include the first clutch portion <NUM> formed on an upper surface. The first clutch portion <NUM> may be coupled to the second clutch portion <NUM> of the housing <NUM>. Specifically, when the planetary gear set <NUM> moves upward, the first clutch portion <NUM> may be coupled to the second clutch portion <NUM>. In this case, rotation of the ring gear <NUM> may be stopped, and low-speed and high-torque washing mode of n:<NUM> may be implemented according to a gear ratio between the sun gear <NUM> and the plurality of pinion gears <NUM>.

The carriers <NUM> and <NUM> may be coupled to the plurality of pinion gears <NUM>. The carriers <NUM> and <NUM> may be coupled to the plurality of pinion gears <NUM> through the connection portion <NUM>.

The carriers <NUM> and <NUM> may include a first carrier <NUM> disposed above the plurality of pinion gears <NUM> and a second carrier <NUM> disposed below the plurality of pinion gears <NUM>. The first carrier <NUM> and the second carrier <NUM> may be connected to the plurality of pinion gears <NUM> through the connection portion <NUM>.

The first carrier <NUM> may include a first coupling hole <NUM> to which the plurality of connection portions <NUM> are coupled, a through hole <NUM> penetrated by the lower region <NUM> of the output shaft <NUM>, a protrusion region <NUM> protruding upward from the upper surface, and the first spline portion <NUM> formed on an inner circumferential surface of the protruding region <NUM>.

The first spline portion <NUM> of the first carrier <NUM> may be coupled to the second spline portion <NUM> of the output shaft <NUM>. Through this, it is possible to stably guide the movement of the planetary gear set <NUM> with respect to the output shaft <NUM>.

The second carrier <NUM> may include a second coupling hole <NUM> to which the plurality of connection portions <NUM> are coupled, and a third clutch portion <NUM> protruding downward from a lower surface.

The third clutch portion <NUM> may be coupled to a fourth clutch portion <NUM> of the rotor shaft <NUM>. Specifically, when the planetary gear set <NUM> is moved downward, the third clutch portion <NUM> of the second carrier <NUM> of the planetary gear set <NUM> is coupled to the fourth clutch portion <NUM> of the rotor shaft <NUM> to rotate together. Through this, since the plurality of pinion gears <NUM> and the rotor shaft <NUM> are synchronized, it is possible to implement high-speed and low-torque spin-drying mode of <NUM>:<NUM>.

The first helical gear <NUM> may be formed on the outer circumferential surface of the sun gear <NUM>, the second helical gear <NUM> may be formed on the outer circumferential surface of the plurality of pinion gears <NUM>, and the third helical gear <NUM> may be formed on the inner circumferential surface of the ring gear <NUM>. Since the planetary gear set <NUM> is moved in the vertical direction as a whole, a helical gear may be formed in the sun gear <NUM>, the plurality of pinion gears <NUM>, and the ring gear <NUM>. Through this, it is possible to increase the safety factor of the gears provided in the planetary gear set <NUM>, and reduce the noise generated during gear rotation.

The planetary gear set <NUM> may be disposed between the first bearing <NUM> and the second bearing <NUM>. Through this, since the length in the axial direction in the drive system of the washing machine <NUM> can be reduced, it is possible to increase the space efficiency of the washing machine.

The ring gear <NUM> may include a groove <NUM> formed on an outer circumferential surface and in which the first actuator <NUM> is disposed. The groove <NUM> may extend in the circumferential direction. The entire planetary gear set <NUM> including the ring gear <NUM> may be moved in the vertical direction by the first actuator <NUM> disposed in the groove <NUM>. Through this, it is possible to move the entire planetary gear set <NUM> in the vertical direction while improving space efficiency.

The first actuator <NUM> may move the planetary gear set <NUM> in the vertical direction. A detailed description of the first actuator <NUM> will be described later.

The rotor shaft <NUM> may be coupled to the motor <NUM>. The rotor shaft <NUM> may be bearing-coupled to the housing <NUM>. The rotor shaft <NUM> may be rotatably coupled to the housing <NUM> by the second bearing <NUM>.

The rotor shaft <NUM> may include a flange portion <NUM> including a protrusion <NUM> coupled to the motor <NUM>, a clutch region <NUM> protruding upward from a central region of the flange portion <NUM>, the fourth clutch portion <NUM> formed on an upper surface of the clutch region <NUM>, a spline region <NUM> protruding upward from the clutch region <NUM>, and the fourth spline portion <NUM> protruding outward in the radial direction from an upper part of the spline region <NUM>.

The fourth clutch portion <NUM> may be coupled to the third clutch portion <NUM> formed on a lower surface of the second carrier <NUM>. Through this, when the planetary gear set <NUM> moves downward, the fourth clutch portion <NUM> is coupled to the third clutch portion <NUM> to rotate integrally.

The fourth spline portion <NUM> may be formed on the outer circumferential surface of the rotor shaft <NUM>. Specifically, the fourth spline portion <NUM> may be formed on an outer circumferential surface of the spline region <NUM>. The fourth spline portion <NUM> may be spline-coupled to the third spline portion <NUM> formed on the inner circumferential surface of the sun gear <NUM>. Through this, it is possible to stably guide the movement of the planetary gear set <NUM> with respect to the rotor shaft <NUM>.

The motor <NUM> may be disposed on one side of the housing <NUM>. The motor <NUM> may be disposed below the housing <NUM>. The motor <NUM> may be coupled to the rotor shaft <NUM>. The motor <NUM> may receive power from the outside and rotate in one direction or the other direction to rotate the rotor shaft <NUM> in one direction or the other direction.

The fifth bearing <NUM> may be disposed between the output shaft <NUM> and the housing <NUM>. The fifth bearing <NUM> may rotatably couple the output shaft <NUM> to the housing <NUM>.

The bushing <NUM> may be disposed between at least a part of the output shaft <NUM> and the rotor shaft <NUM>. The bushing <NUM> may be disposed between the lower region <NUM> of the output shaft <NUM> and the rotor shaft <NUM>. Through this, it is possible to prevent parts from being damaged when the rotational speeds of the rotor shaft <NUM> and the output shaft <NUM> are different.

<FIG> and <FIG> are operational diagrams of a drive system of a washing machine according to an embodiment of the present invention.

Referring to <FIG>, the planetary gear set <NUM> is moved upward by the first actuator <NUM>. In this case, the first clutch portion <NUM> of the ring gear <NUM> of the planetary gear set <NUM> may be engaged with and fixed to the second clutch portion <NUM> of the housing <NUM>. With the ring gear <NUM> fixed, as the rotor shaft <NUM> rotates, the sun gear <NUM> rotates, and the sun gear <NUM> causes the pinion gear <NUM> to rotate and revolve. In this case, the rotational force of the rotor shaft <NUM> is reduced at a gear ratio of n:<NUM> and transmitted to the output shaft <NUM> so that the output shaft <NUM> rotates at low speed and high torque.

Referring to <FIG>, the planetary gear set <NUM> is moved downward by the first actuator <NUM>. In this case, the third clutch portion <NUM> of the second carrier <NUM> of the planetary gear set <NUM> is engaged with the fourth clutch portion <NUM> of the rotor shaft <NUM>, and the plurality of pinion gears <NUM> connected to the second carrier <NUM> do not rotate but revolve. The planetary gear set <NUM> transmits the rotational force of the rotor shaft <NUM> to the output shaft <NUM> at a ratio of <NUM>:<NUM> so that the output shaft <NUM> rotates at high speed and low torque.

According to the drive system of the washing machine <NUM> according to an embodiment of the present invention, it is possible to implement the washing mode and the spin-drying mode by moving the entire planetary gear set <NUM> without a stop operation between ending washing and starting spin-drying.

<FIG> is a perspective view of a drive system of a washing machine according to another embodiment of the present invention. <FIG> is an exploded perspective view of a drive system of a washing machine according to another embodiment of the present invention. <FIG> is a cross-sectional view of a drive system of a washing machine according to another embodiment of the present invention. <FIG> is a perspective view of an output shaft of a drive system of a washing machine according to another embodiment of the present invention. <FIG> is a perspective view of a part of a ring gear of a drive system of a washing machine according to another embodiment of the present invention. <FIG> is a perspective view of a housing of a drive system of a washing machine according to another embodiment of the present invention. <FIG> is a perspective view of a part of a planetary gear set and a rotor of a drive system of a washing machine according to another embodiment of the present invention. <FIG> is a view in which the third carrier is removed from <FIG>. <FIG> is a perspective view of a part of a planetary gear set of a drive system of a washing machine according to another embodiment of the present invention. <FIG> is a perspective view of a rotor of a drive system of a washing machine according to another embodiment of the present invention.

Referring to <FIG>, a drive system of a washing machine <NUM> according to another embodiment of the present invention may include a housing <NUM>, a output shaft <NUM>, a third bearing <NUM>, a fourth bearing <NUM>, a planetary gear set <NUM>, a second actuator <NUM>, a rotor <NUM>, and a motor <NUM>, but may be implemented except for some of these configurations, and does not exclude other additional configurations.

The housing <NUM> may include a cylindrical portion <NUM> extending downward and a sixth clutch portion <NUM> extending radially outward from the cylindrical portion. The sixth clutch portion <NUM> may be engaged with a fifth clutch portion <NUM> of a ring gear <NUM> of the planetary gear set <NUM> when the planetary gear set <NUM> is moved to the upper part or the other side. The sixth clutch portion <NUM> may be formed in a shape complementary to that of the fifth clutch portion <NUM>.

The output shaft <NUM> may extend in the axial direction. The output shaft <NUM> may be coupled to 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 rotatably coupled at the same speed as the rotor <NUM> or at different speeds. The output shaft <NUM> may be bearing-coupled to the rotor <NUM>. In another embodiment of the present invention, the axial direction may be interpreted as meaning the vertical direction based on <FIG>.

A first region <NUM> of the output shaft <NUM> may be disposed within the planetary gear set <NUM>. The first region <NUM> of the output shaft <NUM> may be disposed inside the rotor <NUM>. The first region <NUM> of the output shaft <NUM> may be bearing-coupled to the rotor <NUM>.

A second region <NUM> of the output shaft <NUM> may be disposed above the first region <NUM>. The second region <NUM> of the output shaft <NUM> may be bearing-coupled to the housing <NUM>. The third bearing <NUM> may be disposed between the second region <NUM> of the output shaft <NUM> and the housing <NUM>. The second region <NUM> of the output shaft <NUM> may be rotatably coupled to the housing <NUM> by the third bearing <NUM>. A diameter of the second region <NUM> of the output shaft <NUM> may be larger than that of the first region <NUM>.

The protrusion <NUM> of the output shaft <NUM> may protrude downward from the lower surface of the second region <NUM> and be spaced apart from the first region <NUM> in the radial direction. The protrusion <NUM> of the output shaft <NUM> may be bearing-coupled to the housing <NUM>. The fourth bearing <NUM> may be disposed between the protrusion <NUM> of the output shaft <NUM> and the housing <NUM>. The protrusion <NUM> of the output shaft <NUM> may be rotatably coupled to the housing <NUM> by the fourth bearing <NUM>. A diameter of the protrusion <NUM> of the output shaft <NUM> may be smaller than the diameter of the second region <NUM> and larger than a diameter of the first region <NUM>.

A sixth spline portion <NUM> of the output shaft <NUM> may be formed on an inner circumferential surface of the protrusion <NUM> of the output shaft <NUM>. The sixth spline portion <NUM> may be spline-coupled to a fifth spline portion <NUM> of a third carrier <NUM>. Through this, it is possible to stably guide the movement of the planetary gear set <NUM> with respect to the output shaft <NUM>.

The third bearing <NUM> may be disposed between the housing <NUM> and the output shaft <NUM>. The third bearing <NUM> may bearing-couple the output shaft <NUM> to the housing <NUM>. The third bearing <NUM> may rotatably couple the output shaft <NUM> to the housing <NUM>. The third bearing <NUM> may be disposed between the second region <NUM> of the output shaft <NUM> and the housing <NUM>. The third bearing <NUM> may extend in the circumferential direction.

The fourth bearing <NUM> may be disposed between the housing <NUM> and the output shaft <NUM>. The fourth bearing <NUM> may bearing-couple the output shaft <NUM> to the housing <NUM>. The fourth bearing <NUM> may rotatably couple the output shaft <NUM> to the housing <NUM>. The fourth bearing <NUM> may be disposed between the protrusion <NUM> of the output shaft <NUM> and the housing <NUM>. The fourth bearing <NUM> may extend in the circumferential direction. The fourth bearing <NUM> may be disposed below the third bearing <NUM>. The fourth bearing <NUM> may be disposed above the planetary gear set <NUM>.

A part of the planetary gear set <NUM> may be spline-coupled to the rotor <NUM> and another part of the planetary gear set <NUM> may be spline-coupled to the output shaft <NUM>. The planetary gear set <NUM> may be vertically moved by the second actuator <NUM>.

When the planetary gear set <NUM> is moved to one side or a lower part, a part of the planetary gear set <NUM> may be coupled to the rotor <NUM>. In this case, the rotational force of the rotor <NUM> may be transmitted to the output shaft <NUM> at a ratio of <NUM>:<NUM>.

When the planetary gear set <NUM> is moved to the other side or an upper part, another part of the planetary gear set <NUM> may be coupled to the housing <NUM>. In this case, the rotational force of the rotor <NUM> may be reduced at a gear ratio of n:<NUM> and transmitted to the output shaft <NUM>.

The sun gear <NUM> may be spline-coupled to the rotor <NUM>. Specifically, a seventh spline portion <NUM> formed on an outer circumferential surface of a region extending downward of the sun gear <NUM> may be spline-coupled to an eighth spline portion <NUM> formed on an inner circumferential surface of the rotor <NUM>. <FIG> and <FIG> show that the outer circumferential surface of the sun gear <NUM> is the spur gear <NUM> as an example, but a fourth helical gear may be formed on the outer circumferential surface of the sun gear <NUM>.

The plurality of pinion gears <NUM> may be spaced apart from each other in the circumferential direction. The outer circumferential surfaces of the plurality of pinion gears <NUM> may be coupled to the outer circumferential surfaces of the sun gear <NUM>, respectively. <FIG> and <FIG> show that the outer circumferential surface of the plurality of pinion gears <NUM> are the spur gears <NUM> as an example, but a fifth helical gear may be formed on the outer circumferential surface of the plurality of pinion gears <NUM>.

Another embodiment of the present invention has been described as an example in which the number of the plurality of pinion gears <NUM> is four, but the number of the plurality of pinion gears <NUM> may be variously changed without being limited thereto.

A plurality of connection portions <NUM> may be formed in each of the plurality of pinion gears <NUM>. The plurality of pinion gears <NUM> may be connected to the carriers <NUM> and <NUM> through the connection portion <NUM>.

The ring gear <NUM> may include an inner portion <NUM> and an outer portion <NUM>.

An inner circumferential surface of the inner portion <NUM> of the ring gear <NUM> may be coupled to the plurality of pinion gears <NUM>. <FIG> and <FIG> show the inner circumferential surface of the ring gear <NUM> is a spur gear <NUM> as an example, but a sixth helical gear may be formed on the inner circumferential surface of the ring gear <NUM>.

The outer portion <NUM> of the ring gear <NUM> may include a disk portion <NUM>, a vertical portion <NUM> extending in the axial direction from the outer side in the radial direction of the disk portion, a fifth clutch portion <NUM> formed on an upper surface of the vertical portion <NUM>, a seventh clutch portion <NUM> formed on a lower surface of the vertical portion <NUM>, a horizontal portion <NUM> protruding outward in the radial direction and extending in the circumferential direction from the vertical portion <NUM>, and an actuator groove <NUM> concavely formed inward in the radial direction from the horizontal portion <NUM>.

The fifth clutch portion <NUM> may be formed on an upper surface of the ring gear <NUM>. The fifth clutch portion <NUM> may be engaged with the sixth clutch portion <NUM> of the housing <NUM> when the planetary gear set <NUM> moves upward. Through this, since the rotation of the ring gear <NUM> is stopped without additional parts, it is possible to implement low-speed and high-torque washing mode of n:<NUM>.

The seventh clutch portion <NUM> may be formed on a lower surface of the ring gear <NUM>. The seventh clutch portion <NUM> may be engaged with an eighth clutch portion <NUM> formed on an upper surface of the rotor <NUM> when the planetary gear set <NUM> moves downward. Through this, since the ring gear <NUM> and the rotor <NUM> are synchronized, it is possible to implement high-speed and low-torque spin-drying mode of <NUM>:<NUM>.

The second actuator <NUM> may be disposed in the actuator groove <NUM>. The actuator groove <NUM> may extend in the circumferential direction. The entire planetary gear set <NUM> including the ring gear <NUM> may be moved in the vertical direction by the second actuator <NUM> disposed in the actuator groove <NUM>. Through this, it is possible to move the entire planetary gear set <NUM> in the vertical direction while improving space efficiency.

The carriers <NUM> and <NUM> may include a third carrier <NUM> disposed above the plurality of pinion gears <NUM> and a fourth carrier <NUM> disposed below the plurality of pinion gears <NUM>. The third carrier <NUM> and the fourth carrier <NUM> may be connected to the plurality of pinion gears <NUM> through the connection portion <NUM>.

The third carrier <NUM> may include a second coupling hole <NUM> to which the plurality of connection portions <NUM> are coupled, a through hole penetrated by the first region <NUM> of the output shaft <NUM>, a protrusion region <NUM> protruding upward from the upper surface, and a fifth spline portion <NUM> formed on an outer circumferential surface of the protrusion region <NUM>.

The fifth spline portion <NUM> of the third carrier <NUM> may be coupled to the sixth spline portion <NUM> of the output shaft <NUM>. Through this, it is possible to stably guide the movement of the planetary gear set <NUM> with respect to the output shaft <NUM>.

The fourth helical gear may be formed on the outer circumferential surface of the sun gear <NUM>, the fifth helical gear may be formed on an outer circumferential surface of the plurality of pinion gears <NUM>, and the sixth helical gear may be formed on an inner circumferential surface of the ring gear <NUM>. Since the planetary gear set <NUM> moves in the vertical direction as a whole, helical gears may be formed at the sun gear <NUM>, the plurality of pinion gears <NUM>, and the ring gear <NUM>. Through this, it is possible to increase the safety factor of the gears provided in the planetary gear set <NUM>, and reduce the noise generated during gear rotation.

The planetary gear set <NUM> may be disposed below the third bearing <NUM> and the fourth bearing <NUM>. Since two bearings support the output shaft <NUM> connected to the washing machine tub, rotational stability of the output shaft <NUM> may be improved.

The rotor <NUM> may be coupled to the motor <NUM>. The rotor <NUM> may include a disk portion coupled to the motor <NUM>, an eighth clutch portion <NUM> protruding upward from the outside in the radial direction of the disk portion, a spline protrusion <NUM> protruding upward from a central region of the disk portion, and an eighth spline portion <NUM> formed on an inner circumferential surface of the spline protrusion <NUM>.

The eighth clutch portion <NUM> may be coupled to the seventh clutch portion <NUM> formed on the lower surface of the ring gear <NUM>. Through this, when the planetary gear set <NUM> is moved downward, the seventh clutch portion <NUM> is coupled to the eighth clutch portion <NUM> to rotate integrally.

The eighth spline portion <NUM> may be formed on the inner circumferential surface of the rotor <NUM>. Specifically, the eighth spline portion <NUM> may be formed on the inner circumferential surface of the spline protrusion <NUM>. The eighth spline portion <NUM> may be spline-coupled to the seventh spline portion <NUM> formed on the outer circumferential surface of the sun gear <NUM>. Through this, it is possible to stably guide the movement of the planetary gear set <NUM> with respect to the rotor <NUM>.

The motor <NUM> may be disposed on one side of the housing <NUM>. The motor <NUM> may be disposed below the housing <NUM>. The motor <NUM> may be coupled to the rotor <NUM>. The motor <NUM> may receive power from the outside and rotate in one direction or the other direction to rotate the rotor <NUM> in one direction or the other direction.

<FIG> are operation diagrams of actuators of a drive system of a washing machine according to another embodiment of the present invention.

Referring to <FIG>, the second actuator <NUM> may include a driving portion <NUM>, a first connecting rod <NUM>, a bracket <NUM>, a second connecting rod <NUM>, and a fork portion <NUM>. A driving protrusion <NUM> of the driving portion <NUM> is inserted into a driving hole <NUM> of the first connecting rod <NUM>. When the driving protrusion <NUM> of the driving portion <NUM> rotates in one direction, the first connecting rod <NUM> is moved in the horizontal direction by the fixed bracket <NUM>, and the fork portion <NUM> is moved vertically or axially by the second connecting rod <NUM> connected to the first connecting rod <NUM>. The planetary gear set <NUM> is moved vertically or axially by the fork portion <NUM> inserted into the actuator groove <NUM>. The fork portion <NUM> other than a region connected to the second connecting rod <NUM> may be connected to a support portion <NUM> connected to the housing <NUM>.

The first actuator <NUM> described above may be the same as the second actuator <NUM>. However, the description of the second actuator <NUM> is only an example, and if the planetary gear set <NUM> can be moved in the vertical direction, the second actuator <NUM> can be changed to an actuator applicable to those skilled in the art.

<FIG> are operational diagrams of a drive system of a washing machine according to another embodiment of the present invention.

Referring to <FIG>, the planetary gear set <NUM> is moved upward by the second actuator <NUM>. In this case, the fifth clutch portion <NUM> of the ring gear <NUM> of the planetary gear set <NUM> may be engaged with and fixed to the sixth clutch portion <NUM> of the housing <NUM>. With the ring gear <NUM> fixed, as the rotor <NUM> rotates, the sun gear <NUM> rotates, and the sun gear <NUM> causes the pinion gear <NUM> to rotate and revolve. In this case, the rotational force of the rotor <NUM> is reduced at a gear ratio of n:<NUM> and transmitted to the output shaft <NUM> so that the output shaft <NUM> rotates at low speed and high torque.

Referring to <FIG>, the planetary gear set <NUM> is moved downward by the second actuator <NUM>. In this case, the seventh clutch portion <NUM> of the ring gear <NUM> of the planetary gear set <NUM> is engaged with the eighth clutch portion <NUM> of the rotor <NUM>, and while the ring gear <NUM> rotates together with the rotor <NUM>, the plurality of pinion gears <NUM> do not rotate but revolve. The planetary gear set <NUM> transmits the rotational force of the rotor <NUM> to the output shaft <NUM> at a ratio of <NUM>:<NUM> so that the output shaft <NUM> rotates at high speed and low torque.

Claim 1:
A drive system for a washing machine comprising:
a housing (<NUM>);
a motor (<NUM>) disposed on one side of the housing (<NUM>);
a rotor shaft (<NUM>) coupled to the motor (<NUM>) and bearing-coupled to the housing (<NUM>);
an output shaft (<NUM>) bearing-coupled to the housing (<NUM>), and wherein at least part of the output shaft (<NUM>) is disposed in the rotor shaft (<NUM>);
a planetary gear set (<NUM>) wherein a part of the planetary gear set (<NUM>) is spline-coupled to the rotor shaft (<NUM>), and another part of the planetary gear set (<NUM>) is spline-coupled to the output shaft (<NUM>);
an actuator (<NUM>) configured to move the planetary gear set (<NUM>) in a vertical direction;
a first bearing (<NUM>) disposed between the output shaft (<NUM>) and the housing (<NUM>); and
a second bearing (<NUM>) disposed between the rotor shaft (<NUM>) and the housing (<NUM>),
wherein when the planetary gear set (<NUM>) is moved to one side, a part of the planetary gear set (<NUM>) is coupled to the rotor shaft (<NUM>) configured to transmit a rotational force of the rotor shaft (<NUM>) to the output shaft (<NUM>) at a ratio of <NUM>:<NUM>, and
when the planetary gear set (<NUM>) is moved to other side, another part of the planetary gear set (<NUM>) is coupled to the housing (<NUM>) and is configured to reduce and transmit the rotational force of the rotor shaft (<NUM>) to the output shaft (<NUM>) at a gear ratio of n:<NUM>, and
wherein the planetary gear set (<NUM>) is disposed between the first bearing (<NUM>) and the second bearing (<NUM>).