Patent Description:
The washing machine is driven in two main operating modes with different operating conditions, for example, a washing mode (which may include a rinsing mode) and a spin-drying mode.

Therefore, in order to satisfy both of the above two main operating modes, the washing machine is provided with a planetary gear assembly and a clutch assembly, and drives an drum shaft at low speed and high torque with a gear ratio of n: <NUM> (washing mode), or drives the drum shaft at high speed and low torque with a gear ratio of <NUM>:<NUM> (spin-drying mode).

Here, the drum shaft refers to a shaft coupled to a drum to rotate the drum.

In the case of driving the drum shaft at low speed and high torque with a gear ratio of n: <NUM>, it can be referred to as "deceleration mode", and in the case of driving the drum shaft at high speed and low torque with a gear ratio of <NUM>: <NUM>, it can be referred to as "direct connection mode".

That is, in a normal washing machine, a washing mode (which may include a rinsing mode) is performed by operating the drum shaft at low speed and high torque, and after the washing mode ends, the motor is temporarily stopped, and a draining operation is performed. And, after the draining operation ends, a spin-drying mode starts.

However, the drum shaft must be operated at high speed and low torque in the spin-drying mode.

Therefore, the washing machine driving system includes parts for shifting a rotational force of the motor transmitted to the drum shaft between the washing mode and the spin-drying mode, for example, the planetary gear assembly and the clutch assembly.

As an example of a related art related to the present disclosure, Korean Patent Publication No. <CIT> (hereinafter, referred to as "Related Art <NUM>") and Korean Patent Publication No. <CIT> (hereinafter, referred to as "Related Art <NUM>") disclose a washing machine driving system in which the drum shaft is installed to pass through a carrier and a sun gear shaft of a planetary gear assembly.

However, since the diameter of the sun gear accommodating the drum shaft increases in the washing machine driving system of the Related Art <NUM> and Related Art <NUM>, there is a problem that the reduction ratio is small.

As another example of a related art related to the present disclosure, Korean Patent Publication No. <CIT> (hereinafter, referred to as "Related Art <NUM>") discloses a washing machine driving system in which a planetary gear assembly and a clutch assembly are arranged in series on an axis of a drum shaft.

However, the washing machine driving system of the Related Art <NUM> has a problem that the volume of the drum is reduced due to the planetary gear assembly and the clutch assembly arranged in series on the shaft of the drum shaft.

As still another example of a related art related to the present disclosure, Korean Patent Registration Publication No. <CIT> (hereinafter, referred to as "Related Art <NUM>") discloses a washing machine driving system formed by separating the sun gear of the planetary gear assembly from the drum shaft of the drum assembly.

However, the washing machine driving system of the Related Art <NUM> has an inconvenience of having to fasten the drum shaft and the sun gear inside the drum assembly.

<CIT> discloses a washing machine drive assembly comprising a planetary gear and a coupling disposed within a hollow room between the driving shaft, the carrier and the driven shaft, wherein the coupling is configured to be switched between the washing operation with the reduced speed and the spin-drying operation with the motor full speed transferred to the drum.

A technical problem to be solved by the present invention is to facilitate the assembly process of a washing machine driving system including a planetary gear having compact dimensions.

Another technical problem to be solved by the present disclosure is to provide a washing machine driving system in which a drum shaft and the motor are separated, a planetary gear assembly is placed therebetween. According to the washing machine driving system, a size of a sun gear is not affected by a size of an outer diameter of a drum shaft.

Still another technical problem to be solved by the present disclosure is to provide a washing machine driving system in which a carrier shaft is coupled to a back side end of the drum shaft, a coupling shaft is serration-coupled to the carrier shaft, and a second shaft portion of a carrier provided in the planetary gear assembly is serration-coupled to the coupling shaft.

Still another technical problem to be solved by the present disclosure is to provide a washing machine driving system capable of effectively implementing a high reduction ratio region while having a compact size and using a small motor.

Still another technical problem to be solved by the present disclosure is to provide a washing machine driving system capable of securing the volume of the drum to the maximum.

Still another technical problem to be solved by the present disclosure is to provide a washing machine driving system capable of securing assembly efficiency.

Still another technical problem to be solved by the present disclosure is to provide a washing machine driving system capable of minimizing a space required for the arrangement of the planetary gear assembly and the clutch assembly for manipulating it.

Still another technical problem to be solved by the present disclosure is to provide a front-loading type washing machine having the above-mentioned washing machine driving system.

The present invention is defined by the independent claim. The preferred embodiments are set out in the dependent claims.

The wording "tooth coupling" refers to a state in which teeth of a gear portion provided in a corresponding gear are engaged with each other and coupled to each other.

According to the washing machine driving system according to the present disclosure, a carrier shaft, which is unrelated to the reduction ratio of the planetary gear assembly, is fixedly supported on the drum shaft, and the sun gear, which is related to the reduction ratio of the planetary gear assembly, is rotationally supported on a coupling shaft that rotates integrally with the carrier shaft.

Therefore, since the sun gear, which is related to the reduction ratio of the planetary gear assembly, can be miniaturized, it is possible to compact the planetary gear assembly, and effectively implement a high reduction ratio region while using a small motor.

In addition, the motor and the planetary gear assembly may be assembled and separated at the back side of the washing machine, so it is possible to improve assembly efficiency.

The first fastening member may include a first head portion, the third fastening member may include a second head portion, and the first head portion of the first fastening member and the second head portion of the third fastening member may face each other in an inner space of the carrier shaft.

According to this configuration, since the first head portion of the first fastening member and the second head portion of the third fastening member are positioned in the inner space of the carrier shaft, it is possible to more compactly form the planetary gear assembly.

A front end of the sun gear may be spaced apart from the back end of the drum shaft in an axial direction.

Therefore, even if the outer diameter of the drum shaft is large, the size of the sun gear, which is related to the reduction ratio of the planetary gear assembly, can be formed regardless of the size of the drum shaft, so that it is possible to downsize the sun gear, and accordingly, it is possible to downsize the planetary gear assembly.

The washing machine driving system according to the present disclosure, may further comprise a bearing assembly including a bearing housing in which the gear housing is fixedly supported; a clutch coupled to the gear housing to be slidable toward a front side and a back side along the axial direction of the drum shaft, and integrally rotating with the gear housing; and a clutch driving portion moving the clutch toward the front side or the back side.

The planetary gear assembly and the clutch may be positioned in an inner space formed by a stator provided in a motor.

According to the present disclosure, since the planetary gear assembly and the clutch may be disposed in the inner space of the stator, it is possible to compact the washing machine driving system, and it is possible to secure the volume of the drum to the maximum.

The bearing assembly may further include a first support bearing accommodated inside the bearing housing, the first support bearing may include a first bearing positioned between the bearing housing and the drum shaft to rotationally support the drum shaft, a second bearing positioned between the bearing housing and the carrier shaft to rotationally support the carrier shaft, and a third bearing positioned between the bearing housing and the gear housing to support the gear housing.

According to this configuration, it is possible to effectively support the drum shaft, the carrier shaft, and the gear housing.

The gear housing of the planetary gear assembly may be coupled to the bearing housing by the third bearing.

According to this configuration, it is possible to effectively support the gear housing.

The washing machine driving system may further comprise a second support bearing supporting the sun gear and the third fastening member, and the second support bearing may include a fourth bearing positioned between the coupling shaft and the sun gear, and a fifth bearing positioned between the gear housing and the sun gear.

A front end of the second head portion of the third fastening member may be positioned forward a front end of the first shaft portion of the coupling shaft in the axial direction, and a forward movement of the fourth bearing in the axial direction may be restrained by the second head portion of the third fastening member.

According to this configuration, it is possible to effectively support the coupling shaft and the sun gear.

A back side end of the third fastening member may be fixed to the rotor frame by a fourth fastening member screwed to the third fastening member, and the third fastening member and the sun gear may rotate integrally with the rotor frame.

According to this configuration, it is possible to effectively assemble the planetary gear assembly and the motor at the back side of the washing machine.

The clutch may include a plurality of coupling protrusions at front side and back side ends, respectively, and the bearing housing and the rotor frame each may include a protrusion coupling portion coupled to the plurality of coupling protrusions when the clutch moves toward the front side or the back side.

According to this configuration, since the power transmission path can be adjusted by engaging the clutch with the bearing housing or the rotor frame, the installation space for the clutch can be minimized.

The clutch driving portion may include a clutch motor positioned in a direction perpendicular to the axial direction and coupled to the tub; a drawer coupled to the clutch motor and moving in a direction perpendicular to the axial direction by the clutch motor; a lifter including an arm portion in contact with a back side end of the clutch and moving in the axial direction according to the movement of the drawer; and a return spring positioned between the clutch and the gear housing and applying the clutch pressure toward the back side in the axial direction.

According to this configuration, since a clutch link structure can be formed by simple linear motion of the drawer in a direction perpendicular to the axial direction within a narrow space between the motor and the planetary gear assembly, it is possible to minimize the installation space of the clutch driving portion.

The clutch driving portion may further include a holder for supporting the drawer and the lifter.

According to this configuration, it is possible to effectively support the drawer and the lifter.

The drawer and the lifter each may include an inclined portion for moving the lifter in the axial direction according to the movement of the drawer.

According to this configuration, it is possible to effectively transmit the power of the clutch motor to the clutch.

The lifter may include a guide, and a stator may include a guide insert portion into which the guide is inserted.

According to this configuration, it is possible to effectively support the axial movement of the lifter.

The stator or the lifter may include a moment preventing portion for preventing rotational moment from being applied to the guide when the lifter moves in the axial direction.

Each of the sun gear, the ring gear, and the plurality of pinion gears may include a helical gear.

According to this configuration, it is possible to increase the safety factor of the gears provided in the planetary gear assembly, and reduce operating noise generated during gear rotation.

The washing machine according to the present disclosure may include a washing machine driving system having the above configuration.

Therefore, it is possible to maximize the volume of the drum and improve the assembly efficiency.

According to the present disclosure, since the drum shaft and the motor are separated, and the planetary gear assembly is disposed between the drum shaft and the motor, it is possible to form the size of the sun gear provided in the planetary gear assembly regardless of the size of the outer diameter of the drum shaft.

Therefore, since the size of the sun gear can be reduced, it is possible to compact the planetary gear assembly. In addition, it is possible to effectively implement a high reduction ratio region while using a small motor. Accordingly, it is possible to down-sizing the motor and motor driving circuit.

In addition, since the volume of the drum can be secured as much as the size of the planetary gear assembly is reduced, it is possible to maximize the volume of the drum and improve the assembly efficiency.

In addition, since the carrier shaft is coupled to the back side end of the drum shaft, the coupling shaft is serration-coupled to the carrier shaft, and the second shaft portion of the carrier provided in the planetary gear assembly is serration-coupled to the coupling shaft, it is possible to reliably fix and support the carrier shaft, the coupling shaft, and the second shaft portion of the carrier.

In addition, it is possible to sufficiently secure the axial force necessary for moving the clutch even with a small-sized clutch motor.

In addition, it is possible to increase the safety factor of the gears provided in the planetary gear assembly.

In addition, it is possible to improve the durability and noise performance of the washing machine driving system and increase the driving efficiency.

In addition, it is possible to improve the assembly efficiency of the washing machine driving system.

Effects obtainable from the present disclosure are not limited by the effects mentioned above, and other effects which are not mentioned above can be clearly understood from the following description by those skilled in the art to which the present disclosure pertains.

The accompanying drawings, which are included as a part of the detailed description to help the understanding of the present disclosure, provide embodiments of the present disclosure, and together with the detailed description, describe the technical features of the present disclosure.

Hereinafter, embodiments disclosed in the present disclosure 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.

The suffixes "assembly" and "unit" for elements used in the following description are given or mixed in consideration of only the ease of writing the specification, and do not have distinct meanings or roles by themselves.

In addition, in describing the embodiments disclosed in the present disclosure, 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 disclosure, the detailed description thereof will be omitted.

In addition, the accompanying drawings are only for easily understanding the embodiments disclosed in the present disclosure, the technical disclosure is not limited by the accompanying drawings, and it should be understood that the accompanying drawings include all changes, equivalents, and substitutes included in the scope of the present disclosure.

While terms, such as "first", "second", etc., may be used to describe various elements, such elements must not be limited by the above terms. The above terms are used only to distinguish one element from another.

When an element is referred to as being "coupled" or "connected" to another element, it may be directly coupled to or connected to the other element, however, it should be understood that other elements may exist in the middle.

On the other hand, when an element is referred to as being "directly coupled" or "directly assembled" to another element, it should be understood that there are no other elements in the middle.

The singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise.

In addition, in the present disclosure, it should be understood that the terms "comprise" and "have" specify the presence of stated features, integers, steps, operations, elements, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, or combinations thereof.

Hereinafter, a preferred embodiment according to the present disclosure will be described in detail with reference to the accompanying drawings, however, regardless of the reference numerals, the same or similar elements will be given the same reference numerals and redundant description thereof will be omitted.

The washing machine according to an embodiment of the present disclosure is a so-called drum type washing machine. In addition, this washing machine is a so-called full-automatic washing machine, and is configured to automatically execute a series of washing processes including processes such as washing, rinsing, and spin-drying.

As shown in <FIG>, a washing machine according to the present disclosure may be composed of a main body, a tub <NUM> (fixed tank), a drum <NUM> (rotating tank), a washing machine driving system, a controller (control device), and the like.

The controller may be composed of hardware such as a CPU and memory, and software such as a control program and various data. The controller may include at least one processor. The processor may be configured to execute program instructions maintained on memory.

The main body of the washing machine is a box-shaped container composed of panels or frames, and may constitute an exterior of the washing machine. A circular inlet for putting in and taking out laundry may be formed on the front of the main body.

A door having a transparent window may be installed in the inlet, and the inlet may be opened and closed by the door.

An operation unit having a switch, etc. operated by a user may be installed on the upper side of the inlet in the main body.

The tub <NUM> communicating with the inlet may be installed inside the main body. The tub <NUM> is made of a bottomed cylindrical container capable of storing water, and an opening of the tub <NUM> may communicate with the inlet.

A water supply device including a water supply pipe, a water supply valve, and a detergent injection unit may be provided at the upper part of the tub <NUM>.

The drum <NUM> may be formed of a cylindrical container having a diameter slightly smaller than that of the tub <NUM>, and may be accommodated in the tub <NUM> in a state in which the center line coincides with the tub <NUM>.

The drum <NUM> may have a circular opening corresponding to the inlet, and laundry may be put into the drum <NUM> through the inlet and the circular opening. A plurality of dewatering holes may be formed throughout the entire circumference of the drum <NUM>.

A driving system is installed on a back side of the tub <NUM>. Here, the back side means a side where a motor is positioned, and means the right side based on <FIG> and <FIG>. In addition, a front side means a side where the tub <NUM> is positioned, and means the left side based on <FIG> and <FIG>.

Referring to <FIG>, the driving system may largely include a bearing assembly <NUM>, a second bearing assembly <NUM>, a planetary gear assembly <NUM>, a clutch <NUM>, a clutch driving portion <NUM>, and a motor <NUM>.

The drum <NUM> may be fixed to a front side end of a drum shaft <NUM> protruding through the tub <NUM>. Thus, the drum <NUM> may be driven in a direct driving manner.

The bearing assembly <NUM> may be fixedly supported on the tub <NUM> toward the back side of the tub <NUM>. The bearing assembly <NUM> may include a bearing housing <NUM> fixedly supported on the tub <NUM>. The bearing housing <NUM> may have an inner space for accommodating the drum shaft <NUM>.

Here, "fixed support" means that the tub <NUM> and the bearing assembly <NUM> are supported in a state in which relative rotation between them is impossible, that is, in a fixed state.

The bearing assembly <NUM> may include a first support bearing <NUM> accommodated inside the bearing housing <NUM>.

The first support bearing <NUM> may include a first bearing 120a positioned between the bearing housing <NUM> and the drum shaft <NUM> to rotationally support the drum shaft <NUM>, a second bearing 120b positioned between the bearing housing <NUM> and a carrier shaft <NUM> to rotationally support the carrier shaft <NUM>, and a third bearing 120c positioned between the bearing housing <NUM> and a gear housing <NUM> to support the gear housing <NUM>.

Here, "rotationally support" means that the drum shaft <NUM> is rotatably supported with respect to the bearing housing <NUM>.

Therefore, the first support bearing <NUM> may effectively support the drum shaft <NUM> and the planetary gear assembly <NUM>.

The carrier shaft <NUM> may be fastened and supported by a first fastening member <NUM> at a back side end of the drum shaft <NUM>, and the carrier shaft <NUM> may rotate integrally with the drum shaft <NUM>.

The first fastening member <NUM> may be formed of a screw inserted into an inner space of the carrier shaft <NUM> from a back side of the carrier shaft <NUM> and fastening the carrier shaft <NUM> to the drum shaft <NUM>.

A first head portion 311a of the first fastening member <NUM> may be positioned in the inner space of the carrier shaft <NUM>.

A front end of the carrier shaft <NUM> may be inserted into a back end of the drum shaft <NUM>.

To this end, a groove of a certain depth may be formed at the back end of the drum shaft <NUM>, and a protrusion inserted into the groove of the drum shaft <NUM> may be provided at the front end of the carrier shaft <NUM>.

Splines or serrations may be provided on an inner circumferential surface of the groove formed at the back end of the drum shaft <NUM> and an outer circumferential surface of the protrusion formed at the front end of the carrier shaft <NUM>, respectively.

According to this configuration, the carrier shaft <NUM> can be fixedly supported to the drum shaft <NUM> more reliably.

In addition, when splines or serrations each are formed on the inner circumferential surface of the groove formed at the back end of the drum shaft <NUM> and the outer circumferential surface of the protrusion formed at the front end of the carrier shaft <NUM>, optionally, the first fastening member may be omitted.

A coupling shaft <NUM> may be fastened and fixedly supported at a back side end of the carrier shaft <NUM> by a second fastening member <NUM>, and the coupling shaft <NUM> may rotate integrally with the carrier shaft <NUM>.

The coupling shaft <NUM> may include a first shaft portion 330a inserted into the carrier shaft <NUM>, and a first flange portion 330b fixed to a back end of the carrier shaft <NUM> by the second fastening member <NUM>.

Splines or serrations may be provided on an outer circumferential surface of the first shaft portion 330a of the coupling shaft <NUM> and an inner circumferential surface of the carrier shaft <NUM> into which the first shaft portion 330a is inserted, respectively.

According to this configuration, the coupling shaft <NUM> can be fixedly supported to the carrier shaft <NUM> more reliably.

The second fastening member <NUM> may be made of a screw.

A carrier <NUM> may be coupled to and fixedly supported on the coupling shaft <NUM>.

The carrier <NUM> may include a second shaft portion 340a inserted into the first shaft portion 330a of the coupling shaft <NUM>, and a second flange portion 340b positioned on a back side of the first flange portion 330b of the coupling shaft <NUM>.

Splines or serrations may be provided on a part of an outer circumferential surface of the second shaft portion 340a of the carrier <NUM> and an inner circumferential surface of the first shaft portion 330a of the coupling shaft <NUM>, respectively.

According to this configuration, the carrier <NUM> can be fixedly supported to the coupling shaft <NUM> more reliably.

The carrier <NUM> may rotate integrally with the coupling shaft <NUM>, the carrier shaft <NUM> and the drum shaft <NUM>.

The planetary gear assembly <NUM> may further include the gear housing <NUM>, a sun gear <NUM> accommodated inside the gear housing <NUM>, a ring gear <NUM>, and a plurality of pinion gears <NUM>, in addition to the carrier shaft <NUM>, the coupling shaft <NUM>, and the carrier <NUM>.

The sun gear <NUM> may be rotationally supported on the coupling shaft <NUM> and fixedly supported on a rotor frame <NUM> of the motor <NUM> by a third fastening member <NUM>.

The third fastening member <NUM> may penetrate the sun gear <NUM> in an axial direction and may rotate integrally with the sun gear <NUM>. The third fastening member <NUM> may be formed of a bolt.

A second head portion 315a of the third fastening member <NUM> may be positioned in the inner space of the carrier shaft <NUM>, and face the first head portion 311a of the first fastening member <NUM>, and a front end of the second head part 315a may be positioned in front of a front end of the first shaft portion 330a of the coupling shaft <NUM>.

When the sun gear <NUM> is coupled to the coupling shaft <NUM> using the third fastening member <NUM>, since the motor <NUM> and the planetary gear assembly <NUM> may be assembled and separated on the back side for easy visibility, assembly efficiency can be improved.

In the inner space of the carrier shaft <NUM>, a front end of the sun gear <NUM> may be spaced apart from a back end of the first fastening member <NUM>, that is, the first head portion 311a of the first fastening member <NUM>.

Therefore, the front end of the sun gear <NUM> is spaced apart from the back end of the drum shaft <NUM> in the axial direction.

Specifically, the carrier shaft <NUM> is fixedly supported on the back end of the drum shaft <NUM>, the coupling shaft <NUM> is fixedly supported on the carrier shaft <NUM>, and the third fastening member <NUM> and the sun gear <NUM> are rotationally supported on the coupling shaft <NUM>.

In this way, since the front end of the sun gear <NUM> is spaced apart from the back end of the drum shaft <NUM>, it is possible to downsize the sun gear <NUM> related to the reduction ratio of the planetary gear assembly <NUM>.

Therefore, it is possible to compact the planetary gear assembly <NUM>, and it is possible to effectively implement a high reduction ratio region while using a small motor.

The sun gear <NUM> and the third fastening member <NUM> may be supported by a second support bearing <NUM>.

The second support bearing <NUM> may include a fourth bearing <NUM> positioned between the coupling shaft <NUM> and the sun gear <NUM>, and a fifth bearing <NUM> positioned between the gear housing <NUM> and the sun gear <NUM>.

The first shaft portion 330a of the coupling shaft <NUM> may include a seating portion for seating the fourth bearing <NUM> thereon.

The second head portion 315a of the third fastening member <NUM> may be in contact with the fourth bearing <NUM>.

A back end of the sun gear <NUM> may be coupled to the rotor frame <NUM> of the motor <NUM> by a fourth fastening member <NUM> screwed to a back end of the third fastening member <NUM>.

The ring gear <NUM> may be positioned on an inner wall of the gear housing <NUM>, and may be fixedly supported on the gear housing <NUM>.

The plurality of pinion gears <NUM> may be coupled to the second flange portion 340b of the carrier <NUM>.

The plurality of pinion gears <NUM> coupled to the second flange portion 340b of the carrier <NUM> may rotate or revolve depending on whether the second flange portion 340b of the carrier <NUM> rotates in a state in which they are tooth-coupled to the sun gear <NUM> and the ring gear <NUM>, respectively.

Here, "tooth coupling" refers to a state in which teeth of the gear portion provided in the corresponding gear are engaged with each other and coupled to each other.

For example, in a state in which the second flange 340b of the carrier <NUM> is fixed, the plurality of pinion gears <NUM> each may rotate, but cannot revolve. In addition, in a state in which the second flange portion 340b of the carrier <NUM> rotates, the plurality of pinion gears <NUM> may revolve, or rotate and revolve.

The gear housing <NUM> of the planetary gear assembly <NUM> may be coupled to the bearing housing <NUM> by the third bearing 120c.

According to this configuration, the planetary gear assembly <NUM> is limited in movement in the axial direction. Therefore, if the sun gear <NUM>, the ring gear <NUM>, and the plurality of pinion gears <NUM> each have a helical gear, the safety factor of the gears provided in the planetary gear assembly <NUM> can be increased, and the operating noise generated during gear rotation can reduced.

The motor <NUM> may include the rotor frame <NUM> to which a back side end of the sun gear <NUM> is fixedly coupled, a stator <NUM> positioned in an inner space of the rotor frame <NUM>, and a plurality of permanent magnets <NUM> positioned inside the rotor frame <NUM> and rotating the rotor frame <NUM> by interaction with the stator <NUM>.

Therefore, when the motor <NUM> operates and the rotor frame <NUM> rotates, the sun gear <NUM> fixed to the rotor frame <NUM> rotates, and the drum shaft rotates according to the rotation of the sun gear <NUM>.

At this time, the drum shaft <NUM> may rotate at low speed and high torque or at high speed and low torque, which will be described later.

The rotor frame <NUM> has a space for accommodating the stator <NUM> and the plurality of permanent magnets <NUM> therein.

The stator <NUM> disposed in the inner space of the rotor frame <NUM> may be fixed to the bearing housing <NUM> of the bearing assembly <NUM>, and has an inner space accommodating the planetary gear assembly <NUM>.

That is, the planetary gear assembly <NUM>, in particular, the gear housing <NUM> is positioned in the inner space formed by the stator <NUM>.

The clutch <NUM> for converting a power transmission path through the planetary gear assembly <NUM> may be positioned in the inner space formed by the stator <NUM>.

That is, the clutch <NUM> may be coupled to the gear housing <NUM> to be slidable toward front side and the back side along the axial direction of the drum shaft.

Referring to <FIG>, the clutch <NUM> is formed of two-stage bodies 400a and 400b having different diameters, and splines or serrations may be provided on an inner circumferential surface of a first body 400a having a relatively small diameter and an outer circumferential surface of the gear housing <NUM>, respectively.

In addition, a return spring <NUM> of the clutch driving portion <NUM> is positioned between the inside of a second body 400b having a relatively larger diameter than the first body 400a and the outer surface of the gear housing <NUM>, and between the second body 400b and the outer surface of the second bearing housing <NUM>.

Therefore, the clutch <NUM> may rotate integrally with the gear housing <NUM>, and may move forward and backward along the axial direction.

The clutch <NUM> may include a plurality of coupling protrusions <NUM> and <NUM> at front side end and back side end, respectively.

The coupling protrusion <NUM> at the front side end may be formed at a front side end of the second body 400b, and the coupling protrusion <NUM> at the back side end may be formed at a back side end of the first body 400a.

The bearing housing <NUM> may include a protrusion coupling portion <NUM> coupled to the plurality of coupling protrusions <NUM> when the clutch <NUM> moves forward along the axial direction, and the rotor frame <NUM> may include a protrusion coupling portion <NUM> coupled to the plurality of coupling protrusions <NUM> when the clutch <NUM> moves backward along the axial direction.

A method of driving the washing machine having the driving system according to this configuration will be described with reference to <FIG> and <FIG>.

When the clutch <NUM> moves forward and the coupling protrusion <NUM> at the front side end of the clutch <NUM> is coupled to the protrusion coupling portion <NUM> of the bearing housing <NUM> as shown in <FIG>, rotation of the gear housing <NUM> to which the clutch <NUM> is coupled is restrained.

That is, since the bearing housing <NUM> is fixed to the tub <NUM>, rotations of the bearing housing <NUM>, the clutch <NUM> coupled to the bearing housing <NUM>, and the gear housing <NUM> coupled to the clutch <NUM> are restrained.

Therefore, since the ring gear <NUM> is maintained in a fixed state, while the rotor frame <NUM> and the sun gear <NUM> rotate, the plurality of pinion gears <NUM> revolve around the sun gear <NUM> while rotating on their own, and the rotational force of the sun gear <NUM> is transmitted to the drum shaft <NUM> through the plurality of pinion gears <NUM> and the carrier <NUM> so that the drum shaft <NUM> is driven at low speed and high torque.

Then, when the clutch <NUM> moves to the back side and the coupling protrusion <NUM> of the clutch <NUM> is coupled to the protrusion coupling portion <NUM> of the rotor frame <NUM>, the sun gear <NUM>, the clutch <NUM>, and the gear housing <NUM> to which the clutch <NUM> is coupled rotate integrally while the rotor frame <NUM> rotates.

Therefore, since the carrier <NUM> also rotates integrally with the gear housing <NUM>, the rotational speed of the carrier <NUM> coincides with the rotational speed of the sun gear <NUM>, and accordingly, the drum shaft <NUM> is driven at high speed and low torque.

According to this configuration, since the power transmission path may be adjusted by coupling the clutch <NUM> to the bearing housing <NUM> or the rotor frame <NUM>, the clutch <NUM> may move within a narrow space. Therefore, the installation space of the clutch <NUM> can be minimized.

Since the planetary gear assembly <NUM> and the clutch <NUM> are disposed in the inner space of the stator <NUM>, it is possible to compact the washing machine driving system and secure the maximum volume of the drum <NUM>.

In order to be able to adjust the power transmission path by changing the position of the clutch <NUM> as described above, the washing machine drive system of the present disclosure further includes the clutch driving portion <NUM>.

The clutch driving portion <NUM> may include a clutch motor <NUM>, a drawer <NUM>, a lifter <NUM>, and a return spring <NUM>.

The clutch motor <NUM> may be positioned in a direction perpendicular to the axial direction and may be coupled to the tub <NUM>.

The drawer <NUM> may be coupled to the clutch motor <NUM> and may move in the direction perpendicular to the axial direction by the clutch motor <NUM>. When the drawer <NUM> is moved, a part of the drawer <NUM> may be positioned between a space between the rotor frame <NUM> and the tub <NUM>.

The lifter <NUM> has a C-type arm portion <NUM> that is in contact with a back side end of the clutch <NUM>. It is also possible to have a ring-type arm portion instead of the C-type arm portion <NUM>, and it is also possible to replace the C-type arm portion with another component capable of pressing the clutch <NUM> forward.

The lifter <NUM> may move in the axial direction according to the movement of the drawer <NUM>.

To this end, the drawer <NUM> and the lifter <NUM> each may include an inclined portion <NUM> to allow the lifter <NUM> to move in the axial direction according to the movement of the drawer <NUM>.

According to this configuration, it is possible to effectively transmit the power of the clutch motor <NUM> to the clutch <NUM>.

The return spring <NUM> may be positioned inside the second body 400b of the clutch <NUM>.

Therefore, the return spring <NUM> may be positioned between the clutch <NUM> and the gear housing <NUM> and between the clutch <NUM> and the second bearing housing <NUM>, and press the clutch <NUM> toward the back side in the axial direction.

According to this configuration, since a clutch link structure may be formed by simple linear motion of the drawer <NUM> in the direction perpendicular to the axial direction within a narrow space between the motor <NUM> and the planetary gear assembly <NUM>, it is possible to minimize an installation space of the clutch driving portion <NUM>.

The clutch driving portion <NUM> may further include a holder <NUM> for supporting the drawer <NUM> and the lifter <NUM>. According to this configuration, it is possible to effectively support the drawer <NUM> and the lifter <NUM> using the holder <NUM>.

The lifter <NUM> may include a guide <NUM>, and the stator <NUM> may include a guide insertion portion <NUM> into which the guide <NUM> is inserted.

According to this configuration, it is possible to effectively support the axial movement of the lifter <NUM>.

In addition, the stator <NUM> may include a moment preventing portion <NUM> for preventing rotational moment from being applied to the guide <NUM> when the lifter <NUM> moves in the axial direction.

In the above, it has been described that the moment preventing portion <NUM> is provided in the stator <NUM> as an example, but the moment preventing portion may be provided in the lifter <NUM>.

According to this configuration, it is possible to effectively prevent malfunction of the lifter, and it is possible to effectively transmit the power of the clutch motor <NUM> to the clutch <NUM>.

According to this configuration, when the clutch motor <NUM> operates to pull the drawer <NUM> in the deceleration mode, the lifter <NUM> moves forward along the inclined portion <NUM> of the drawer <NUM>, and the C-type arm portion <NUM> of the lifter <NUM> presses the clutch <NUM> forward, and accordingly, the return spring <NUM> mounted inside the clutch <NUM> in a compressed state is further compressed.

Then, the coupling protrusion <NUM> of the clutch <NUM> separates from the protrusion coupling portion <NUM> of the rotor frame <NUM> and is separated from each other. Subsequently, when power is applied to the motor <NUM> to slowly rotate the rotor frame <NUM>, while the coupling protrusion <NUM> of the clutch <NUM> is forwardly inserted into the protrusion coupling portion <NUM> formed on the bearing housing <NUM>, the rotation of the ring gear <NUM> is restrained.

In addition, in the direct connection mode, when the clutch motor <NUM> pushes the drawer <NUM>, the lifter <NUM> moves rearward along the inclined portion <NUM> of the drawer <NUM> and the return spring <NUM> mounted inside the clutch <NUM> in a compressed state becomes less compressed.

Then, the coupling protrusion <NUM> of the clutch <NUM> separates from the protrusion coupling portion <NUM> of the bearing housing <NUM> and is separated from each other. Subsequently, when power is applied to the motor <NUM> to slowly rotate the rotor frame <NUM>, the coupling protrusion <NUM> of the clutch <NUM> has a rotational degree of freedom while being inserted into the protrusion coupling portion <NUM> of the rotor frame <NUM> by the spring force of the return spring <NUM>, and the ring gear <NUM> has a degree of rotational freedom while being integrated with the rotor frame <NUM>.

According to the washing machine driving system of this configuration, after inserting the drum assembly including the drum shaft <NUM> into the bearing housing <NUM> fixed to the tub <NUM>, and inserting the carrier shaft <NUM> into the second bearing 120b, coupling the carrier shaft <NUM> to the drum shaft <NUM> using the first fastening member <NUM>, inserting the fourth bearing <NUM> into the coupling shaft <NUM>, coupling the coupling shaft <NUM> to the carrier shaft <NUM> using the second coupling member <NUM> while the third coupling member <NUM> is inserted into the coupling shaft <NUM>, mounting the motor <NUM> on a back side of the planetary gear assembly <NUM>, and fastening the fourth fastening member <NUM> to the third fastening member <NUM> may be performed sequentially. Thus, it is possible to complete the installation of the planetary gear assembly <NUM> and the motor <NUM> by sequentially performing the above operations.

Therefore, since it is possible to assemble the planetary gear assembly and the motor on the back side for easy visibility, the assembly efficiency can be improved.

Claim 1:
A washing machine driving system comprising a planetary gear assembly (<NUM>) comprising:
a carrier shaft (<NUM>) fixedly supported on a back end of a drum shaft (<NUM>) by a first fastening member (<NUM>);
a coupling shaft (<NUM>) including a first shaft portion (330a) inserted into the carrier shaft (<NUM>) and a first flange portion (330b) fixed to a back end of the carrier shaft (<NUM>) by a second fastening member (<NUM>), and fixedly supported on the carrier shaft (<NUM>);
a carrier (<NUM>) including a second shaft portion (340a) inserted into the first shaft portion (330a) of the coupling shaft (<NUM>) and a second flange portion (340b) positioned at a back side of the first flange portion (330b) of the coupling shaft (<NUM>), and fixedly supported on the coupling shaft (<NUM>);
a sun gear (<NUM>) rotationally supported on the coupling shaft (<NUM>) and fixedly supported on a rotor frame (<NUM>) of a motor (<NUM>) by a third fastening member (<NUM>);
a plurality of pinion gears (<NUM>) coupled to the second flange portion (340b) of the carrier (<NUM>), and tooth-coupled with the sun gear (<NUM>);
a ring gear (<NUM>) tooth-coupled with the plurality of pinion gears (<NUM>); and
a gear housing (<NUM>) accommodating the sun gear (<NUM>), the plurality of pinion gears (<NUM>), and the ring gear (<NUM>) therein.