Washing machine and motor control method

Abstract

To provide a washing machine capable of achieving a new mode of washing and dewatering.SOLUTION: A washing machine comprises: a water tank; a rotary tub rotating with respect to the water tank; a pulsator disposed in the rotary tub; a motor having a shaft, which extends in an axial direction and rotates at least either one of the pulsator or the rotary tub, a rotor, which is connected to the shaft and rotates in a circumferential direction, and a stator fitted to the water tank; and a control part to control the motor. The rotor and the stator are disposed so as to be spaced away in the axial direction and face each other. The rotor and the shaft are held so as to be capable of vibrating with respect to the axial direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a washing machine and a method for controlling a motor.

Background Art

[0002] Conventionally, washing machines that wash or dehydrate objects by rotating a pulsator or a rotating tub have been used.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a washing machine and a method for controlling a motor of the washing machine that can realize a new mode of washing and dehydration by not only rotating a pulsator or the like but also moving it in the axial direction.

Means for Solving the Problems

[0005] The washing machine according to the embodiment includes a water tank, a rotating tub that rotates with respect to the water tank, a pulsator disposed in the rotating tub, a shaft that extends in the axial direction and rotates at least one of the pulsator and the rotating tub, a rotor that is connected to the shaft and rotates in the circumferential direction, a stator that is attached to the water tank, and a motor having the stator, and a control unit that controls the motor. The rotor and the stator are disposed to face each other with a space therebetween in the axial direction, and the rotor and the shaft are held so as to be vibratable with respect to the axial direction.

Brief Description of the Drawings

[0006]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0007] Hereinafter, a washing machine and a method for controlling the motor of the washing machine according to the embodiment will be described with reference to the drawings. In the following description, components having the same or similar functions are denoted by the same reference numerals. And redundant descriptions of these components may be omitted.

[0008] (First Embodiment) FIG. 1 is a cross-sectional view perpendicular to the front-rear direction of the washing machine 1 according to the present embodiment. In the following description, the installation surface side of the washing machine 1, that is, the vertically downward side, is defined as the lower side of the washing machine, and the side opposite to the installation surface, that is, the vertically upward side, is defined as the upper side of the washing machine 1. Also, based on the direction in which the user standing in front of the washing machine 1 views the washing machine 1, the left and right are defined. Further, the side closer to the user standing in front of the washing machine 1 as viewed from the washing machine 1 is defined as "front", and the far side is defined as "rear". In this specification, the "lateral direction" means the left-right direction in the above definition. In this specification, the "depth direction" means the front-rear direction in the above definition. In the figure, the +X direction is the right direction, the -X direction is the left direction, the +Y direction is the rear direction, the -Y direction is the front direction, the +Z direction is the upper direction, and the -Z direction is the lower direction.

[0009] In the following description, the axial direction of the rotation axis O is simply referred to as the "axial direction". In the present embodiment, the rotation axis O is oriented in the vertical direction. Of the two sides in the axial direction, the upward-facing direction may be referred to as the "one side D1 in the axial direction", and the downward-facing direction may be referred to as the "other side D2 in the axial direction". Further, the radial direction centered on the rotation axis O may be simply referred to as the "radial direction". Furthermore, the circumferential direction centered on the rotation axis O may be simply referred to as the "circumferential direction".

[0010] [Washing machine 1] The washing machine 1 includes, for example, a housing 11, a top cover 12, a water tank 13, a rotary tub 14, a pulsator 15, a motor 16, and a control unit 9. The washing machine 1 is a so-called vertical-axis type washing machine in which the rotation axis O of the rotary tub 14 is oriented in the vertical direction. Note that the washing machine 1 is not limited to the vertical-axis type, and may be a so-called drum-type washing machine of the horizontal-axis type in which the rotation axis of the rotary tub is horizontal or inclined downward toward the rear.

[0011] The housing 11 is generally configured in a rectangular box shape by, for example, a steel plate. The top cover 12 is made of, for example, synthetic resin and is provided on the upper part of the housing 11. The water tank 13 and the rotary tub 14 function as a washing tub and a dehydration tub for accommodating clothes to be washed. The water tank 13 and the rotary tub 14 are provided in the housing 11. The water tank 13 and the rotary tub 14 are configured in a container shape with an open upper surface. The water in the water tank 13 flows out from the drain port 131 and is drained to the outside through the drain valve 132.

[0012] The motor 16 has a flat cylindrical outer appearance with a diameter smaller than that of the water tank 13, and is assembled below the water tank 13 such that the rotation axis O passes through its center.

[0013] [2. Configuration of motor 16] FIG. 2 is a perspective view of the motor 16. The motor 16 has a shaft 17, a rotor 20, and a stator 30. The motor 16 is a direct drive motor that directly rotates the shaft 17. Also, the motor 16 is an axial gap type motor in which the rotor 20 and the stator 30 are arranged to face each other with a gap in the axial direction. By flowing an alternating current through the stator coil 30c of the stator 30 to generate a rotating magnetic field, the rotor 20 rotates. The shaft 17 is connected to the rotor 20 and rotates in accordance with the rotation of the rotor 20. The rotation axis of the shaft 17 coincides with the rotation axis O of the rotary tub 14.

[0014] The shaft 17 is connected to the rotary tub 14 and the pulsator 15 via a clutch mechanism (not shown). The clutch mechanism selectively transmits the rotation of the motor 16 to the rotary tub 14 and the pulsator 15. During washing and rinsing, the motor 16 and the clutch mechanism transmit the driving force of the motor 16 to the pulsator 15 with the rotation of the rotary tub 14 stopped, and directly drive the pulsator 15 to rotate forward and backward at a low speed. On the other hand, during dehydration and the like, the motor 16 and the clutch mechanism transmit the driving force of the motor 16 to the rotary tub 14, and drive the rotary tub 14 and the pulsator 15 to rotate in one direction at a high speed.

[0015] Figure 3 is a diagram showing the operation of the thrust vibration of the shaft 17. The shaft 17 is held so as to be able to advance and retreat in the axial direction. The vibration of the shaft 17 in the axial direction is also referred to as "thrust vibration V". When the shaft 17 undergoes thrust vibration, the pulsator 15 moves up and down with respect to the rotary tub 14. Also, when the shaft 17 undergoes thrust vibration, the axial gap G formed between the rotor 20 and the stator 30 changes. The advance and retreat range in the axial direction due to the thrust vibration V of the shaft 17 is regulated by a stopper or the like.

[0016] As shown in FIG. 3, when the shaft 17 moves to one axial side D1, the pulsator 15 moves upward with respect to the rotary groove 14. Further, the rotor 20 moves upward with respect to the stator 30. The axial (shaft direction) interval G formed between the rotor 20 and the stator 30 becomes narrower. The narrowest interval G is also referred to as the "first interval G1".

[0017] As shown in FIG. 1, when the shaft 17 moves to the other axial side D2, the pulsator 15 moves downward with respect to the rotary groove 14. Further, the rotor 20 moves downward with respect to the stator 30. The axial (shaft direction) interval G formed between the rotor 20 and the stator 30 becomes wider. The widest interval G is also referred to as the "second interval G2" (G1 < G2).

[0018] The motor 16 may have a sensor that can detect the length of the axial (shaft direction) interval G formed between the rotor 20 and the stator 30 and the change in the interval G. The control unit 9 can acquire the length of the interval G and the change in the interval G from the sensor.

[0019] The rotor 20 is located on the other axial side D2 of the stator 30. The rotor 20 is arranged on the other axial side D2 of the coil 35 described later. The rotor 20 is annular with the rotation axis O as the center. The rotor 20 is fixed to the shaft 17. The rotor 20 rotates in the circumferential direction together with the shaft 17 around the rotation axis O. The rotor 20 includes a back yoke 21, a plurality of magnets 24, and a rotor holding portion 29.

[0020] The back yoke 21 is located on the other axial side D2 of the magnet 24. The rotor 20 is fixed to the shaft 17 in the back yoke 21. The rotor holding portion 29 holds the back yoke 21 and the plurality of magnets 24.

[0021] The plurality of magnets 24 are arranged along the circumferential direction centered on the rotation axis O. The magnets 24 have the axial direction as the magnetic pole direction. The plurality of magnets 24 arranged in the circumferential direction are arranged with the N poles and S poles alternating and reversing. The plurality of magnets 24 are held by the rotor holding portion 29.

[0022] In the present embodiment, the magnet 24 is a ferrite magnet. However, the magnet 24 may be other types of magnets (for example, rare earth magnets such as neodymium magnets).

[0023] The magnet 24 may be an anisotropic magnet or an isotropic magnet. When the magnet 24 is an anisotropic magnet, by setting the magnetization easy axis of the magnet 24 in the axial direction, the magnetic force in the axial direction of the magnet 24 can be increased as a whole. On the other hand, when an isotropic magnet is used as the magnet 24, the rotor 20 can be manufactured at a lower cost compared to an anisotropic magnet.

[0024] The stator 30 is located on one axial side D1 of the rotor 20. The stator 30 is arranged on one axial side D1 of the magnet 24. The stator 30 is annular centered on the rotation axis O. The stator 30 includes a stator core 31, a plurality of coils 35, and a stator holding portion 39.

[0025] The stator core 31 is annular along a plane perpendicular to the axial direction centered on the rotation axis O. The stator core 31 includes a plurality of teeth portions 33.

[0026] The plurality of teeth portions 33 are arranged at equal intervals along the circumferential direction of the rotation axis O. The teeth portion 33 has an isosceles trapezoidal shape when viewed from the axial direction. When viewed from the axial direction, the two sides of the teeth portion 33 that are parallel to each other extend perpendicular to the radial direction of the rotation axis O. Also, among the two sides of the teeth portion 33 that are parallel to each other when viewed from the axial direction, the short side is arranged on the side of the rotation axis O, and the long side is arranged on the side away from the rotation axis O.

[0027] The coil 35 is wound around the tooth portion 33 via an insulator (not shown). The insulator (not shown) is, for example, bobbin-shaped. The coil 35 is attached to each of the plurality of tooth portions 33. The plurality of coils 35 are arranged side by side in the circumferential direction. The end portions of the coil 35 are drawn out from the stator 30 and connected to a power supply device. Thereby, an electric current flows through the coil 35. Each coil 35 is wound around an axis parallel to the rotation axis O. Therefore, when an electric current flows through the coil 35, magnetic poles are formed in the axial direction. That is, the coil 35 forms magnetic poles on the rotor 20 side facing in the axial direction.

[0028] The stator holding portion 39 is made of an insulating resin material. The stator holding portion 39 holds the stator core 31 and the plurality of coils 35, and firmly fixes the stator 30 to the bottom 13e of the water tank 13.

[0029] FIG. 4 is a diagram showing the elastic member 19. The motor 16 may have an elastic member 19 that suppresses rattling due to the thrust vibration V. The elastic member 19 is, for example, a spring or a damper. The elastic member 19 is inserted into the axial (axial) interval G formed between the rotor 20 and the stator 30. The elastic member 19 can suppress the occurrence of unnecessary thrust vibration V by allowing the thrust vibration V only when the force generating the thrust vibration V in the axial (axial) direction is equal to or greater than a predetermined force.

[0030] The control unit 9 controls the overall operation of the washing machine 1, such as the rotational operation of the motor 16. Further, the control unit 9 receives operation inputs to the washing machine 1 via a touch panel (not shown) or a network. The control unit 9 includes, for example, a computer having a processor such as a CPU, a memory, and a storage medium, and can execute software. The functions of the control unit 9 are realized by software.

[0031] [Operation of the washing machine 1] Next, the operation of the washing machine 1 including the motor 16 will be described.

[0032] FIG. 5 is a graph showing the relationship between the rotational speed and torque of the motor 16. By changing the interval G, the rotational speed-torque characteristics of the motor 16 change. That is, the motor 16 is a motor whose rotational speed-torque characteristics change when the interval G changes.

[0033] When the interval G becomes as narrow as the first interval G1, the magnet 24 and the coil 35 approach each other, so the motor 16 tends to output high torque. In this case, the rotational speed-torque characteristics of the motor 16 are suitable for "washing" that requires high torque.

[0034] When the interval G becomes as wide as the second interval G2, the magnet 24 and the coil 35 move away from each other, so the motor 16 tends to output a high rotational speed. In this case, the rotational speed-torque characteristics of the motor 16 are suitable for "dehydration" that requires a high rotational speed.

[0035] When the washing machine 1 performs washing (such as easy washing or rinsing), the water tank 13 is filled with washing water. Buoyancy is generated on the pulsator 15, and the pulsator 15 moves upward with respect to the rotary tub 14. Further, the rotor 20 moves upward with respect to the stator 30. The axial interval G formed between the rotor 20 and the stator 30 becomes narrow. As a result, the rotational speed-torque characteristics of the motor 16 change to those suitable for "washing" that requires high torque.

[0036] When the washing machine 1 performs dehydration, the washing water is discharged from the water tank 13. The pulsator 15 moves downward with respect to the rotary tub 14. Further, the rotor 20 moves downward with respect to the stator 30. The axial interval G formed between the rotor 20 and the stator 30 becomes wide. As a result, the rotational speed-torque characteristics of the motor 16 change to those suitable for "dehydration" that requires a high rotational speed.

[0037] According to the washing machine 1 of this embodiment, by only taking in and out the washing water in washing and dehydration, the pulsator 15 can be moved in the axial direction (axis direction), and the rotational speed - torque characteristics of the motor 16 can be automatically changed to those suitable for each case.

[0038] (Second Embodiment) Referring to FIGS. 6 to 9, the washing machine 1B of the second embodiment will be described. In the following description, for the components common to those already described, the same reference numerals will be given and the overlapping description will be omitted.

[0039] FIG. 6 is a functional block diagram of the control unit 9B. The washing machine 1B includes a control unit 9B instead of the control unit 9 as compared with the washing machine 1 of the first embodiment. The control unit 9B has an interval control unit 92 that actively controls the interval G in addition to a rotational speed - torque control unit 91 that controls the rotational speed and torque of the motor 16.

[0040] The interval control unit 92 actively controls the interval G based on information such as a sensor that can detect the length of the interval G and the change in the interval G. For example, the interval control unit 92 controls the interval G to a desired interval by flowing a DC exciting current through at least a part of the coil 35.

[0041] FIGS. 7 to 9 are diagrams showing examples of water flow due to the thrust vibration V. For example, when the rotor 20 and the shaft 17 are not rotating, the interval control unit 92 may cause the rotor 20 and the shaft 17 to undergo a thrust vibration V to vibrate the pulsator 15 in the vertical direction, thereby generating a water flow that vibrates in the vertical direction in the washing water W.

[0042] As shown in FIG. 7, the interval control unit 92 may generate a thrust vibration V1, which is a thrust vibration V with a large vibration amplitude, to generate a water flow that vibrates greatly in the vertical direction in the washing water W. This makes it easy to gently replace the object to be washed and facilitates washing.

[0043] As shown in Fig. 8, the interval control unit 92 may generate a thrust vibration V2, which is a minute vibration thrust vibration V, to generate a water flow that vibrates like ripples (ripple vibration) in the washing water W. It is easy to gently scrub the object to be washed.

[0044] As shown in Fig. 9, the interval control unit 92 may simultaneously generate the thrust vibration V1 and the thrust vibration V2 to generate a more complex water flow in the washing water W. While gently scrubbing the object to be washed, it is easy to gently replace and wash the object to be washed.

[0045] For example, in a state where the rotor 20 and the shaft 17 are rotating, the interval control unit 92 may vibrate the rotor 20 and the shaft 17 with the thrust vibration V and vibrate the pulsator 15 in the vertical direction to generate a more complex water flow in the washing water W.

[0046] According to the washing machine 1B of the present embodiment, the control unit 9B actively controls the interval G to generate the thrust vibration V, and a new mode of washing and dehydration can be realized.

[0047] According to the washing machine 1B of the present embodiment, by actively controlling the interval G by the control unit 9B, the rotational speed-torque characteristics of the motor 16 can be changed to be suitable for the operations (such as washing and dehydration) of the washing machine 1B.

[0048] (Third Embodiment) Referring to Fig. 10, the washing machine 1C of the third embodiment will be described. In the following description, for the components that are the same as those already described, the same reference numerals will be given and the overlapping description will be omitted.

[0049] Fig. 10 is a cross-sectional view perpendicular to the front-rear direction of the washing machine 1C. The washing machine 1C includes a motor 16C instead of the motor 16 as compared with the washing machine 1 of the first embodiment.

[0050] In addition to the shaft 17, the rotor 20, and the stator 30, the motor 16C further includes a drive unit 18. The drive unit 18 is a mechanical structure that controls the interval G. The drive unit 18 is controlled by the control unit 9.

[0051] When the washing machine 1C performs washing, the control unit 9 controls the drive unit 18, and as a result, the drive unit 18 narrows the interval G. As a result, the rotational speed-torque characteristic of the motor 16 changes to a characteristic suitable for "washing" that requires high torque.

[0052] When the washing machine 1 performs dehydration, the control unit 9 controls the drive unit 18, and as a result, the drive unit 18 widens the interval G. As a result, the rotational speed-torque characteristic of the motor 16 changes to a characteristic suitable for "dehydration" that requires a high rotational speed.

[0053] For example, when the rotor 20 and the shaft 17 are not rotating, the drive unit 18 may cause the rotor 20 and the shaft 17 to perform a thrust vibration V, cause the pulsator 15 to vibrate in the vertical direction, and generate a water flow that vibrates in the vertical direction in the washing water W.

[0054] As shown in FIG. 7, the drive unit 18 may generate a thrust vibration V1 that is a thrust vibration V with a large vibration amplitude, and generate a water flow that vibrates greatly in the vertical direction in the washing water W. It is easy to gently replace the object to be washed and facilitate washing.

[0055] As shown in FIG. 8, the drive unit 18 may generate a thrust vibration V2 that is a thrust vibration V with a minute vibration, and generate a water flow that vibrates like a ripple (ripple vibration) in the washing water W. It is easy to gently scrub the object to be washed.

[0056] As shown in FIG. 9, the drive unit 18 may generate the thrust vibration V1 and the thrust vibration V2 simultaneously, and generate a more complex water flow in the washing water W. It is easy to gently scrub the object to be washed while gently replacing the object to be washed and facilitating washing.

[0057] For example, in a state where the rotor 20 and the shaft 17 are rotating, the drive unit 18 may cause the rotor 20 and the shaft 17 to undergo thrust vibration V, cause the pulsator 15 to vibrate in the vertical direction, and generate a more complex water flow in the washing water W.

[0058] According to the washing machine 1C of the present embodiment, the drive unit 18 that controls the interval G by a mechanical structure can more accurately control the interval G to generate thrust vibration V, and realize a new mode of washing and dehydration.

[0059] According to the washing machine 1C of the present embodiment, the drive unit 18 that controls the interval G by a mechanical structure can change the rotational speed-torque characteristics of the motor 16 to be suitable for the operation (such as washing and dehydration) of the washing machine 1C.

[0060] When the washing machine has a drying function, the control unit 9 may control the interval G as follows. When the washing machine performs drying, since there is no water load, the control unit 9 preferably widens the interval G and dries the clothes by rotating at a low torque. Also, at the initial stage of drying, since the clothes contain a lot of water, high-torque rotation may be required. In this case, the control unit 9 may control the interval G so that high-torque rotation is performed at the initial stage of drying and low-torque rotation is performed after drying has progressed to a certain extent. Further, when the drying progresses and the clothes become lighter, the control unit 9 may control the interval G so as to vibrate the pulsator 15 in the vertical direction to lift the clothes. A space through which air passes is created under the clothes, promoting the drying of the lower side of the clothes (the pulsator 15 side) where drying is difficult, and suppressing uneven drying.

[0061] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalent scope.

Description of Symbols

[0062] 1, 1B, 1C... washing machine, 9, 9B... control unit, 11... housing, 13... water tank, 14... rotary tank, 15... pulsator, 16, 16C... motor, 17... shaft, 18... drive unit, 19... elastic member, 20... rotor, 30... stator, D1... one axial side, D2... the other axial side, G... interval (gap), V... thrust vibration

Claims

1. A water tank, A rotating tank that rotates with respect to the water tank, A pulsator disposed in the rotating tank, A shaft extending in the axial direction for rotating at least one of the pulsator and the rotating tank, a rotor connected to the shaft and rotating in the circumferential direction, and a stator attached to the water tank, a motor having the same, A control unit for controlling the motor, Comprising, The rotor and the stator are disposed opposite to each other with a space therebetween in the axial direction, The rotor and the shaft are held so as to be vibratable with respect to the axial direction, A washing machine.

2. When the rotor and the shaft move to one side in the axial direction, the space is narrowed, When the rotor and the shaft move to the other side in the axial direction, the space is widened, The washing machine according to claim 1.

3. When the pulsator moves upward due to the buoyancy of the washing water in the water tank, the rotor and the stator move to one side in the axial direction, and the space is narrowed, The washing machine according to claim 1.

4. The motor has an elastic member inserted into the space, The washing machine according to claim 1.

5. The motor has a sensor for detecting at least one of the length of the space and the change in the space, The washing machine according to claim 1.

6. The control unit controls the space by controlling the current flowing through the coil of the stator, The washing machine according to claim 1.

7. The control unit vibrates the shaft and the pulsator in the vertical direction by controlling the space, and generates a water flow vibrating in the vertical direction in the washing water in the water tank, The washing machine according to claim 6.

8. The control unit slightly vibrates the shaft and the pulsator in the vertical direction by controlling the space, and generates a water flow slightly vibrating in the vertical direction in the washing water in the water tank, The washing machine according to claim 6.

9. Further comprising a drive unit which is a mechanical structure for controlling the space, The washing machine according to claim 1.

10. When the washing machine performs washing, the drive unit narrows the space, When the washing machine performs dehydration, the drive unit widens the space, The washing machine according to claim 9.

11. The drive unit vibrates the shaft and the pulsator in the vertical direction by controlling the space, and generates a water flow vibrating in the vertical direction in the washing water in the water tank, The washing machine according to claim 9.

12. By controlling the interval between the shaft and the pulsator, the drive unit causes the shaft and the pulsator to vibrate slightly in the vertical direction, generating a water flow that vibrates slightly in the vertical direction in the washing water in the water tank. The washing machine according to claim 9.

13. A control method for a motor mounted on a washing machine, in which a rotor and a stator are arranged to face each other with a space therebetween in the axial direction and the space can be controlled. When the washing machine performs washing, the space is narrowed. When the washing machine performs dehydration, the space is widened. A control method for a motor.

14. The space is controlled by controlling the current flowing through the coil of the stator. The control method for a motor according to claim 13.

15. The space is controlled by controlling it with a mechanical structure. The control method for a motor according to claim 13.

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