WO2007126233A2

WO2007126233A2 - Drum type washing machine and method for controlling the same

Info

Publication number: WO2007126233A2
Application number: PCT/KR2007/001958
Authority: WO
Inventors: Bon Kwon Koo; Jin Woong Kim; Young Suk Kim
Original assignee: Lg Electronics Inc.
Priority date: 2006-04-27
Filing date: 2007-04-23
Publication date: 2007-11-08
Also published as: DE112007000459T5; DE112007000459B4; US20070251023A1; WO2007126233A3; KR100793796B1; KR20070105782A

Abstract

A drum type washing machine has an access hole (110) and a drum door (200) for closing the access hole (110) provided an the cylindrical sidewall of the drum (100). The enclosure of the washing machine includes an access opening (15) that aligns with the assess hole (110) of the drum (100). A motor (300) of the washing machine is coupled to both the drum door (200) and the drum (100) itself. Thus, the motor (300) can be used to rotate the drum (100) and the door (200) during washing operations. A clutch unit (400) selectively couples and decouples the motor (300) from the drum (100) so that the drum door (200) can be rotated with respect to the drum (100) to open and close the access hole (110) of the drum (100).

Description

DRUM TYPE WASHING MACHINEAND METHODFOR CONTROLLING THE SAME

Technical Field

[1] The present invention relates to a drum type washing machine, and more specifically, to an access hole and a drum door of such a washing machine, and methods of controlling the same.

Background Art

[2] Washing machines are used to clean laundry using chemical actions relying on wash water and detergent. Washing machines can be categorized based on the method used to perform washing action. For example, washing machines can be categorized into an agitator-type washing machine, a plusator-type washing machine and a drum-type washing machine. An agitator-type washing machine includes a vertical agitator that is rotated back and forth to perform washing actions. A pulsator-type washing machine includes a plate-shaped pulsator that is moved to generate water currents to perform washing. A drum-type washing machine performs washing by rotating a horizontally oriented cylindrical drum having plural lifters that project in towards the center of the drum. As the drum rotates, the lifters produce a friction force between the wash water and the laundry.

[3] The rotation shafts of the drums in the agitator-type washing machine and the pulsator-type washing machine are oriented vertically. Also, these types of machines typically require less time to complete a washing cycle. However, the fabric of the laundry being washed may be damaged in the agitator-type washing machines and the pulsator-type washing machines. In contrast, the rotation shaft of a drum-type washing machine is horizontally provided, and the drum type washing machine tends to damage to fabric less than the other types.

[4] Drum-type washing machines can have a front loading system, where a door closes off one end of the cylindrical drum. In other types of drum-type washing machines the ends of the cylindrical drum are closed off, but an access hole is formed on the circumferential surface of a cylindrical drum. If an access hole is formed in the circumferential surface of the cylindrical drum, the access hole is opened and closed by a drum door which is coupled to the cylindrical drum. There may also be a separate door on the housing of the washing machine at a position that corresponds to the drum door on the cylindrical drum.

[5] To use the drum-type washing machine, a user opens the door on the washing machine housing, and then the drum door, to load laundry into the drum. The user then closes the drum door and locks the drum door using a latch. After he/she closes the door on the housing, the user activates a washing cycle. Once washing is complete, the user opens the housing door, releases the latch, and opens the drum door to unload the laundry through the access hole. Disclosure of Invention Technical Problem

[6] In some instances, it may be inconvenient for the user to have to open and closes the drum door with his/her hands. In addition, when the user tries to open and close the drum door, it may be possible for the user to injure his/her hands. Technical Solution

[7] To solve the technical problem mentioned above, one aspect of the embodiment provides a washing machine comprising: an enclosure including an access opening formed thereon; a tub mounted in the enclosure; a drum rotatably mounted inside the tub and including an access hole provided on a circumferential cylindrical surface of the drum; a drum door that moves to open and close the access hole; a motor mounted on the enclosure, wherein a rotor of the motor is rotationally fixed to one of the drum and the drum door; and a clutch unit that selectively rotationally couples the rotor to the other of the drum and the drum door.

[8] Another aspect of the embodiment provides a method for controlling a washing machine having a cylindrical drum and a drum door that moves substantially parallel to the cylindrical surface of the drum to open and close an access hole on the cylindrical surface of the drum, comprising: rotationally coupling a rotor of a motor of the washing machine to both the drum and the drum door so that the motor rotates the drum and the drum door together; disconnecting one of the drum and the drum door from the rotor; and rotating the rotor and the other of the drum and the drum door to move the drum door with respect to the drum to open and close the access hole of the drum.

[9] Still another aspect of the embodiment provides a method for controlling a washing machine having a cylindrical drum and a drum door that moves substantially parallel to the cylindrical surface of the drum to open and close an access hole on the cylindrical surface of the drum, wherein the washing machine also includes an enclosure with an access opening, the method comprising: rotating both the drum and the drum door together with a motor until the access hole is aligned with the access opening; disconnecting the drum from the motor such that the drum door is still rotationally coupled to the motor; and moving the drum door with respect to the drum with the motor to open the access hole of the drum. Advantageous Effects [10] In a washing machine according to the embodiments, both the drum and the drum door that opens and closes the drum are operated by one motor. Also, since the driving force of the motor is selectively transmitted to the drum by the clutch unit, the motor may rotate both the drum and the drum door at the same time or the motor may rotate only the drum door with respect to the drum to open and close the access hole of the drum. As a result, the drum door can be opened and closed automatically, which is convenient to the user. Also, the user does not have to open and close the drum door directly and it enables the user to use the washing machine safely. Brief Description of the Drawings

[11] The embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, and wherein:

[12] FlG. 1 is a diagram schematically illustrating a drum-type washing machine according to a first embodiment;

[13] FlG. 2 is a partial cross-sectional view illustrating a drum, a tub and a driving part provided in the drum-type washing machine of FlG. 1 ;

[14] FlG. 3 is a cross-sectional view illustrating portions of the drum shown in FlG. 2;

[15] FIGS. 4 and 5 are partial cross-sectional views illustrating the driving part of the washing machine shown in FlG. 2;

[16] FlG. 6 is a perspective view illustrating an alternate embodiment of a clutch unit of a washing machine as shown in FlG. 2; and

[17] FlG. 7 is a flow chart of a method for controlling a drum-type washing machine.

Mode for the Invention

[18] Reference will now be made in detail to specific embodiments, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[19] As shown in FlG. 1, a drum-type washing machine includes an enclosure 10 having an access opening 11 provided, for example, at an upper front portion thereof. A tub 20 is provided inside the enclosure 10 to store water. A rotatable drum 100 is provided within the tub 20. An access hole 110 and a drum door 200 are provided along a circumferential surface of the drum 100. Laundry may be loaded into the drum 100 through the access hole 110 and the drum door 200 may open and close the access hole 110. Also, a plurality of through-holes may be formed on the drum 100 and water may pass through the through-holes.

[20] An opening is provided in the tub 20 to connect the access opening 11 of the enclosure 10 and the access hole 110 of the drum 100 to each other. As a result, a user can load or unload the laundry into or out of the drum 100 through the access hole 110. The door 15 of the washing machine opens and closes both the access opening 11 of the enclosure 10 and the opening of the tub 20. Thus, when the door 15 is closed, the tub 20 is able to contain water. The drum door 200 opens and closes the access hole 110 of the drum 100.

[21] In addition, as shown in FlG. 2 and FlG. 3, the drum-type washing machine includes a motor 300 that operates the drum 100 and the drum door 200. The motor 300 includes a stator 310 and a rotor 320. As shown in FlG. 2, the stator 310 is secured to the tub 20 and the rotor 320 covers the stator 310.

[22] The rotor of the motor 300 is coupled to the drum door 200 to operate the drum door

200. More specifically, a door shaft 210 is coupled between the rotor 320 and a predetermined portion of the drum door 200. As a result, when the rotor 320 rotates, the drum door 200 is rotated with the rotor.

[23] The drum door 200 is movable with respect to the drum 100. The drum door 200 moves along a direction that is substantially parallel to the circumferential surface of the drum 100. Typically, the drum door 200 is provided at an inner portion of the drum 100 and it slides along an inner circumference of the drum 100 to open and close the access hole 110 of the drum 100. A middle portion of the drum door 200 has a shape corresponding to the access hole 110. An end of the drum door 200 extends down one end of the cylindrical drum and is secured to door shaft 210, as shown in FlG. 4. Thus, when the rotor 320 is rotated, the drum door 200 can be rotated by the door shaft 210 relative to the drum, to thereby cause the middle portion of the drum door 200 to slides along the circumferential direction of the drum 100 to open and close the access hole 110.

[24] At least one first bar 120 projects toward the inside of the drum 100 from an edge of the access hole 110 of the drum 100. At least one second bar 130 projects toward an inside of the drum 100 from the other opposite edge of the access hole 110. At least one first hook 220 is formed at an edge of the drum door 200, and the first bar 120 engages with the first hook 220. At least one second hook 230 is formed at the other opposite edge of the drum door 200, and the second bar 130 engages with the second hook 230. As shown in FlG. 3, the first hook 220 and the second hook 230 have curved shapes, respectively. When the access hole 110 is closed, the first hook 220 and the second hook 230 are facing the first bar 120 and the second bar 130, respectively.

[25] After rotating in a particular direction during a washing operation, even after the drum 100 stops, the first hook 220 may be engaged to the first bar 120. However, as shown in FlG. 3, the second hook 230 may slightly separate from the second bar 130 after the drum 100 stops so that the second bar 130 and the second hook 230 may be prevented from interfering with an opening motion of the drum door 200. When the drum door covers the access hole 110, and the drum 100 is rotating, the second hook 230 is pushed against the second bar 130 by a centrifugal force so that the door remains closed.

[26] The drum door 200 may include a weight 250 attached to the second hook 230, or to a predetermined portion adjacent to the second hook 230, so that the second bar 130 will remain engaged with the second hook 230 while the drum 100 is rotating. The weight 250 attached to the drum door 200 pushes the drum door 200 toward an inner surface of the drum 100 using a centrifugal force when the drum 100 is rotating. As a result, the drum door 200 is closely contacted with the drum 100 to prevent the laundry inside the drum 100 from escaping through a gap.

[27] While the drum door 200 is directly connected to the motor 300 and moves with the rotor of the motor 300, the drum 100 is selectively connected to the motor 300 by a clutch unit. The clutch unit 400 selectively transfers the rotational force of the motor 300 to the drum 100.

[28] As shown in FIGS. 4 to 6, a hollow drum shaft 150 is fixed to the drum 100. An end of the drum shaft 150 is fixed to the drum 100 and the opposite end of the drum shaft 150 passes through the tub 20 to extend toward the motor 300. The door shaft 210 and the drum shaft 150 are arranged in the same shaft direction and the door shaft 210 passes through the drum shaft 150. An oil-less bearing 215 is interposed between the door shaft 210 and the drum shaft 150. In addition, a bearing 155 is interposed between the drum shaft 150 and the tub 20 to rotatably support the drum 100 with respect to the tub 20.

[29] The clutch unit 400 is provided between the drum shaft 150 and the motor 300 to selectively transfer the rotational force of the motor 300 to the drum shaft 150. The clutch unit 400 includes a clutch member 410 and an actuator 450. The clutch member 410 is movable along a longitudinal direction of the door shaft 210 and the drum shaft 150. The actuator 450 operates the clutch member 410.

[30] The clutch member 410 includes a first serration 411 and a second serration 412. As shown in FlG. 4, the first serration 411 and the second serration 412 are formed on inner circumferential surfaces of cylindrical portions of the clutch member 410. The first serration 411 is able to engage the rotor 320 of the motor 300 and the second serration 412 is able to engage with the hollow drum shaft 150 attached to the drum 100. The clutching member 410 is shaped such that an end of the drum shaft 150 can be received in a hollow cylindrical portion of the clutch member having the second serration 412.

[31] As shown in FlG. 4, a fourth serration 330 on the rotor 320 engages with the first serration 411 to rotationally couple the clutch member 410 to the rotor 320. A fifth serration 151 on the hollow drum shaft 150 engages with the second serration 412 to rotationally couple the clutch member to the drum 100.

[32] Furthermore, the clutch member 410 may include a third serration 413 that is able to engage a sixth serration 25 on the tub 20. As shown in FlG. 5, the third serration 413 may be engaged to the sixth serration 25 of the tub 20, when the first serration 411 is disengaged from the fourth serration 330 of the motor 300. At the same time, the second serration 412 would engaged to the fifth serration 151 of the hollow drum shaft 150 attached to the drum 100.

[33] When the clutch member 410 moves toward the motor 300, as shown in FlG. 4, the first serration 411 engages the fourth serration 330 of the rotor 320, and the second serration 412 engages the fifth serration 151 on the hollow drum shaft 150. As a result, the rotational force of the rotor 320 is transmitted to the drum 100, as well as to the drum door 200. In this configuration, the drum 100 will rotated together with the drum door 200 when the rotor turns.

[34] When the clutch member 410 moves toward the drum 100, as shown in FlG. 5, the first serration 411 disengages from the fourth serration 330, which decouples the rotor and the drum 100. At the same time, the second serration 412 and the third serration 413 engage the fifth serration 151 and the sixth serration 25, respectively. In this configuration, the drum 100 will not rotate together with the rotor of the motor. Instead, when the rotor moves, only the drum door 200 is rotated by the rotor of the motor. Thus, moving the rotor will cause the door 200 to open and close the access hole 110 of the drum 100. Note, the engagement between the hollow drum shaft 150 and the clutch member 410, and the engagement between the clutch member 410 and the tub 20 prevent the drum from rotating with respect to the tub 20.

[35] In alternate embodiments, the sixth serration 25 that engages the third serration 413 on the clutch member 410 may be formed on some other stationary portion of the washing machine, such as a bracket fixed to the tub 20 or a portion of the enclosure 10. This would also prevent the tub from rotating when only the door 200 is to be moved.

[36] The actuator 450 moves the clutch member 410 along the door shaft 210 and the drum shaft 150. The actuator 450 may comprise various different mechanisms, as would be apparent to one of ordinary skill in the art. With reference to FIGS. 4 and 5, in the illustrated embodiment the actuator 450 may include a solenoid 451 and a magnetic member 452. The solenoid 451 may be attached to either the tub 20 or the clutch member 410. The magnetic member 452 would be provided on the other of the tub 20 and the clutch member 410. When electric current is applied to the solenoid 451, the solenoid 451 would pull the magnetic member 452 and thus the clutch member 410 would move from the position shown in FlG 4 towards the tub 20 to the position shown in FlG. 5. If the direction of the polarity of the electric current applied to the solenoid 451 is reversed, the clutching member 410 could be moved in an opposite direction so that it returns to the position shown in FlG. 4.

[37] In some embodiments, a spring 430 is interposed between the rotor 320 and the clutch member 410 to bias the clutch member 410 into a certain position. The solenoid 451 would be used to overcome the force of the spring 430 and thereby move the clutch member to a new position. Then, when the power applied to the solenoid 451 is removed, the spring 430 would move the clutch member 410 back to its original position, as shown in FlG. 4.

[38] In an alternate embodiment, as shown in FlG. 6, the actuator 450 includes a lever 453 connected to the clutch member 410, and the motor 300 operates the lever 453. An end of the lever 453 would be directly or indirectly connected to the motor 300. A middle portion of the lever 453 is connected to a hinge 454. The opposite end of the lever 453 is connected to the clutch member 410.

[39] When the motor 300 is operated in a first direction to pull the end of the lever 453, the lever 453 rotates about the hinge 453 in a first direction to move the clutch member 410 toward one of the motor 300 and the drum 100. When the motor 300 is operated in a second direction to push the end of the lever 453, the lever 453 rotates about the hinge 454 in a second direction and thus the clutch member 410 moves toward the other of the motor 300 and the drum 100. As a result, the clutch member 410 is moved toward either the motor 300 or the drum 100 according to the direction of the motor operation.

[40] Referring back to FlG. 2, a first sensor 31 and a second sensor 32 may be provided in the drum-type washing machine to monitor a rotational position of the drum within the tub. The first sensor 31 is attached to the drum 100. The second sensor 32 is attached to a non-rotating portion of the washing machine, such as the tub 20. The first sensor 31 and the second sensor 32 may comprise a magnet and a hall sensor which interact to send a signal indicative of the rotational position of the drum. In particular, the sensors indicate when the access opening 11 of the housing and the access hole 110 of the drum 100 are aligned.

[41] Specifically, when the drum 100 is rotated slowly by the motor 300, and the first sensor 31 is brought into alignment with and the second sensor 32 so that they face each other, a signal would be generated to indicate that the access opening 11 and the access hole 110 are aligned. The signal sent by the first sensor 31 and/or the second sensor 32 would be transmitted to a controller (not shown). The controller then determines that the access opening 11 and the access hole 110 are aligned. Hence, the controller (not shown) sends a control signal to operate the clutch unit 400.

[42] In a washing machine as described above, the drum 100 as well as the drum door 200 may be operated by one motor 300. A controller of the washing machine would control the clutch unit 400 to connect the motor 300 to both the drum 100 and the drum door 200, such that the motor 300 rotates the drum 100 and the drum door 200. The controller would also control the clutch unit 400 to disconnect the drum 100 from the motor 300, such that the drum door 200 can be rotated with respect to the drum 100 to open and close the drum 100. The clutch unit would couple the drum 100 to a fixed part, such as the tub 20, to efficiently prevent the drum 100 from rotating together with the drum door 200 when the drum door 200 is rotated with respect to the drum 100

[43] Although the embodiment described above has a drum that is selectively coupled to the rotor by the clutch unit, in alternate embodiments, the drum door could be the element that is selectively coupled to the motor, while the drum itself is always coupled to the motor. In this alternate embodiment, to open and close the door the clutch would decouple the drum door from the motor and then rotate the drum with respect to the drum door to open and close the access hole. The clutch unit might also act to couple the drum door to a stationary part of the washing machine during the door opening and closing actions.

[44] A method of controlling a drum-type washing machine and a door of a rotating drum of the washing machine will now be described with reference to FlG. 7. This method will refer to an embodiment as illustrated in the drawings, where the drum is selectively coupled to the motor. However, the method could be slightly altered if an alternate embodiment of the washing machine were used where the motor is selectively coupled to the drum door instead.

[45] During the operation, or when the washing machine is stopped, the controller (not shown) would detect whether there is a command for opening the drum 100 (SlOO) or a command for closing the drum 100 (S200). If the controller (not shown) receives a command for opening the drum 100, the controller (not shown) first identifies whether the rotation speed of the drum 100 is below a predetermined value (SIlO). The rotation speed of the drum 100 may be determined by a speed sensor, or by monitoring signals output by the first and second sensors 31 and 32. If it is identified that the rotation speed of the drum 100 is substantially higher than the predetermined value, the controller (not shown) controls the motor 300 and the drum 100 to lessen the rotational speed below a predetermined value (Sl 15). This is because it is preferred to stop the drum 100 when the access hole 110 and the access opening 11 are aligned, and doing so is easier to accomplish if the rotational speed of the drum is slow.

[46] If the drum 100 is stopped or the rotation speed of the drum 100 is below the predetermined value, the controller (not shown) identifies whether the access hole 110 of the drum which is covered by the drum door 200 and the access opening 11 of the enclosure 10 are aligned (S 120). Here, the controller (not shown) identifies whether the access hole 110 and the access opening 11 are aligned by using the signals output from the first sensor 31 and/or the second sensor 32. If it is determined that the access hole 110 and the access opening 11 are not aligned, the controller (not shown) repeatedly checks whether the access hole 110 and the access opening 11 are aligned as the motor 300 continues to rotate the drum 100 and the drum door 200 below the predetermined speed. When the controller determines that the access hole 110 and the access opening 11 are aligned, by signals of the first and/or second sensors 31 and 32, the controller (not shown) controls the drum 100 to stop rotating (S130).

[47] When the drum 100 stops, the controller (not shown) operates the clutching unit 400 to disconnect the drum from the motor 300 (S 140). Even though the motor 300 and the drum 100 are disconnected from each other, the connection between the motor 300 and the drum door 200 is maintained. As a result, if the motor 300 is rotated in this condition, the drum door 200 is rotated with respect to the drum 100.

[48] As the motor 300 and the drum are being disconnected from each other, the controller (not shown) secures the drum 100 to a fixed part of the washing machine, for example, the tub 20 or a bracket fixed to the tub 20 (S 150), so that the drum 100 may be prevented from being rotated together with the drum door 200 by the operation or the vibration of the motor 300.

[49] When the motor 300 is disconnected from the drum 100 and the drum 100 is secured to the tub 20, the motor 300 is operated by the controller (not shown). Hence, the drum door 200 is rotated with respect to the drum 100 and the access hole 110 of the drum 100 is opened (S 160). In some embodiments, the rotation of the motor 300 stops after the rotor rotates through a predetermined angle to fully open the access hole 100. In alternate embodiments, the motor 300 may simple rotate to open the access hole 110 until further rotation is impossible. In this case, a protrusion or the like may be provided on the drum 100 to limit the rotation of the drum door 200.

[50] When the drum 100 is opened through the above process, the user may load or unload laundry into or out of the drum 100. When a command for closing the drum 100 is transmitted by the user or a preset program (S200), the controller (not shown) rotates the rotor 320 of the motor 300 to close the access hole 110 of the drum 100 with the drum door 200. As described above, this could involve rotating the rotor 320 and the drum door 200 through a predetermined angle, or until the drum door 200 stops moving and the first hook 220 engages the first bar 120 of the drum 100.

[51] When the drum door 200 closes the drum 100, the controller (not shown) controls the clutch unit 400 to connect the drum 100 to the motor 300 (220). When a command for rotating the drum 100 is received (S230), for example, preset washing programs are to be performed, the controller (not shown) operates the motor 300 and thus the drum 100 and the drum door 200 are rotated at the same time (S240).

[52] Any reference in this specification to "one embodiment," "an embodiment,"

"example embodiment," etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.

[53] Although various embodiments have been described, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, variations and modifications are possible in the component parts and/or the subject combination of arrangements while still falling within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. Industrial Applicability

[54] In a washing machine as described above, both the drum and the drum door that opens and closes the drum are operated by one motor. Also, since the driving force of the motor is selectively transmitted to the drum by the clutch unit, the motor may rotate both the drum and the drum door at the same time or the motor may rotate only the drum door with respect to the drum to open and close the access hole of the drum. As a result, the drum door can be opened and closed automatically, which is convenient to the user. Also, the user does not have to open and close the drum door directly and it enables the user to use the washing machine safely.

Claims

[1] A washing machine, comprising: an enclosure including an access opening formed thereon; a tub mounted in the enclosure; a drum rotatably mounted inside the tub and including an access hole provided on a circumferential cylindrical surface of the drum; a drum door that moves to open and close the access hole; a motor mounted on the enclosure, wherein a rotor of the motor is rotationally fixed to one of the drum and the drum door; and a clutch unit that selectively rotationally couples the rotor to the other of the drum and the drum door.

[2] The washing machine of claim 1, wherein the drum door moves relative to the drum in a direction substantially parallel to the circumferential cylindrical surface of the drum to open and close the access hole.

[3] The washing machine of claim 1, wherein the drum door is positioned within the drum, and wherein the drum door is pushed against the inner cylindrical surface of the drum by centrifugal force during rotation of the drum.

[4] The washing machine of claim 1, wherein when the clutch unit rotationally couples the rotor to the other of the drum and the drum door the drum and the drum door rotate together with the rotor.

[5] The washing machine of claim 4, wherein when the clutch unit decouples the rotor from the other of the drum and the drum door, rotation of the rotor causes the drum door to move with respect to the drum to open and close the access hole.

[6] The washing machine of claim 5, wherein when the clutch unit decouples the rotor from the other of the drum and the drum door, the clutch unit also couples the other of the drum and the drum door to a fixed part of the washing machine.

[7] The washing machine of claim 6, wherein the fixed part comprises the tub.

[8] The washing machine of claim 1, further comprising: a first sensor part mounted on the drum; and a second sensor part mounted on a fixed part of the washing machine such that the first sensor will pass by the second sensor as the drum rotates, and wherein at least one of the first and second sensor parts generate a signal when the first and second sensor parts are adjacent one another.

[9] The washing machine of claim 1, further comprising: a hollow drum shaft having a first end that is coupled to the drum and a second end that passes through and extends from the tub; and a door shaft that is rotationally coupled to the rotor, wherein the door shaft passes through the hollow drum shaft and is attached to the drum door.

[10] The washing machine of claim 9, wherein the clutch unit comprises: a clutch member that is rotationally coupled to the hollow drum shaft and that is movably mounted between the rotor and the hollow drum shaft, wherein the clutch member can move along a longitudinal direction of the hollow drum shaft, and wherein the clutch member can be selectively rotationally coupled to the rotor; and an actuator for moving the clutch member in the longitudinal direction of the hollow drum shaft.

[11] The washing machine of claim 10, wherein a first serration on the rotor can selectively engage a second serration on the clutch member to rotationally couple the clutch member to the rotor.

[12] The washing machine of claim 11, wherein the actuator can operate to move the clutch member in a longitudinal direction such that the second serration on the clutch member disengages from the first serration on the rotor.

[13] The washing machine of claim 12, wherein when the clutch member is moved to a position where the second serration on the clutch member is disengaged from the first serration on the rotor, the clutch member is rotationally fixed to a stationary part of the washing machine.

[14] The washing machine of claim 12, wherein when the clutch member is moved to a position where the second serration on the clutch member is disengaged from the first serration on the rotor, a third serration on the clutch member engages with a fourth serration on a fixed portion of the washing machine to rotationally fix the clutch member to the fixed portion of the washing machine.

[15] The washing machine of claim 12, wherein the actuator can also operate to move the clutch member in a longitudinal direction such that the second serration on the clutch member engages the first serration on the rotor.

[16] The washing machine of claim 12, further comprising a biasing member that biases the clutch member into a position at which the second serration on the clutch member engages the first serration on the rotor.

[17] A method for controlling a washing machine having a cylindrical drum and a drum door that moves substantially parallel to the cylindrical surface of the drum to open and close an access hole on the cylindrical surface of the drum, comprising: rotationally coupling a rotor of a motor of the washing machine to both the drum and the drum door so that the motor rotates the drum and the drum door together; disconnecting one of the drum and the drum door from the rotor; and rotating the rotor and the other of the drum and the drum door to move the drum door with respect to the drum to open and close the access hole of the drum.

[18] The method of claim 17, further comprising rotationally fixing the one of the drum and the drum door that is disconnected from the rotor to a fixed part of the washing machine before performing the rotating step.

[19] A method for controlling a washing machine having a cylindrical drum and a drum door that moves substantially parallel to the cylindrical surface of the drum to open and close an access hole on the cylindrical surface of the drum, wherein the washing machine also includes an enclosure with an access opening, the method comprising: rotating both the drum and the drum door together with a motor until the access hole is aligned with the access opening; disconnecting the drum from the motor such that the drum door is still rotationally coupled to the motor; and moving the drum door with respect to the drum with the motor to open the access hole of the drum.

[20] The method of claim 19, further comprising rotationally fixing the drum to a fixed part of the washing machine before performing the moving step.