Actuators and drive units for washing machines

Abstract

To make reciprocating motion of an actuator efficient and appropriate.SOLUTION: An actuator 100 comprises a movable member 120 that reciprocates along a stationary member 110. The stationary member 110 has an electric cable 113 and two magnets 114a, 114b. The movable member 120 has two salient pole cores 120a, 120a, and a connection core 120b connecting base end portions of the salient pole cores 120a, 120a. The movable member 120 reciprocates by switching the electric conduction direction of the electric cable 113.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The disclosed technology relates to an actuator and a drive unit for a washing machine. [Background technology]

[0002] Demands for household washing machines include compact size, large capacity, low noise, and energy saving. Therefore, development of drive units for washing machines is underway to meet these demands.

[0003] Washing machines require a wide range of torque for each process, including washing, rinsing, and spin-drying. To achieve this wide range of torque, it has long been common to use a clutch to switch the transmission.

[0004] In recent years, drive units that directly rotate the pulsator or drum using a motor are becoming mainstream. In such drive units, the rotational force can be changed using inverter control, but the motor must have high efficiency, which places limitations on cost and other factors. For this reason, switching technology using a transmission and clutch is once again attracting attention.

[0005] Furthermore, in recent years, in technical fields such as robotics, there is a need to widely change the rotational force of a motor, and therefore similarly, switching techniques using transmissions and clutches have been attracting attention.

[0006] In relation to the disclosed technology, Patent Document 1 discloses a linear actuator.

[0007] The linear actuator consists of a stator with a core and a coil, and a mover with a magnet and a yoke. The mover's magnet consists of a main magnet and a pair of spring magnets located on either side of it.

[0008] Patent Documents 2 and 3 disclose drive units for washing machines that include a clutch that includes a structure similar to the linear actuator of Patent Document 1. The clutch includes a mover having a magnet with magnetic poles aligned in the order of SNS in the direction of the rotation axis, and a stator having a clutch coil. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-288088 [Patent Document 2] Japanese Patent Application Publication No. 2020-114288 [Patent Document 3] Japanese Patent Publication No. 2020-124381 Summary of the Invention [Problem to be solved by the invention]

[0010] When a clutch is configured with a linear actuator with a magnet as a moving element, the large thrust generated during reciprocating motion can cause a loud impact noise when the clutch is switched, resulting in noise. Additionally, friction caused by contact at the clutch meshing points and impacts from collisions can cause wear and tear on the clutch.

[0011] As a measure to suppress the impact noise, the clutch in Patent Document 3 proposes a method of providing a buffer material at the contact point. However, this method has the problem of being expensive. The clutch in Patent Document 3 also proposes a method of mitigating the collision by generating a thrust force in the opposite direction just before the clutch collides. However, this requires instantaneous switching to a reverse current at the appropriate timing, which is difficult to control.

[0012] Furthermore, if the mover has a magnet, there is a risk that the magnet may come off when the mover rotates at high speed, and there are other problems such as difficulty in manufacturing.

[0013] Therefore, the disclosed technology realizes an actuator that can perform reciprocating motion efficiently and appropriately so as to solve such problems. [Means for solving the problem]

[0014] The disclosed technology relates to an actuator including a fixed member that is fixed in place when in use, and a movable member that reciprocates along the fixed member in a predetermined first direction.

[0015] The fixed member has an electric wire positioned apart in a second direction intersecting the first direction and extending in a direction intersecting both the first direction and the second direction, and two magnets arranged between the electric wire and the movable member while lined up in the first direction and arranged with the same magnetic poles facing the first direction, and the movable member has two salient pole cores arranged side by side in the first direction, each of whose tip portions can be closely opposed to the two magnets, and a connecting core connecting base end portions of the two salient pole cores at a position away from the two magnets, and the movable member reciprocates by switching the direction of current flow in the electric wire.

[0016] In other words, in this actuator, the movable member reciprocates linearly relative to the fixed member when the current direction is switched. The movable member is only a core and does not have a magnet. Therefore, there is no risk of the magnet becoming detached even when rotating at high speed. The movable member has two salient pole cores and a connecting core that form the magnetic flux path, and its structure is simple and easy to manufacture.

[0017] The fixed member is provided with a pair of magnets in a predetermined arrangement with the same magnetic poles facing each other, along with electric wires that form a magnetic field between the fixed member and the movable member when current is applied. By providing such magnets on the fixed member, the movable member can be stably held in two positions that serve as starting points for reciprocating motion when no current is applied. Then, by applying current to the movable member, a smooth and appropriate propulsive force can be generated. This allows the movable member to reciprocate efficiently and appropriately, effectively suppressing impact noise.

[0018] The actuator may be such that the movable member is integrally formed using a plate-like soft magnetic material, and a flange portion that projects in a direction opposite to the first direction is provided at each tip end portion of the salient pole core.

[0019] By providing such a flange, the movable member can be operated more stably.

[0020] The fixed member and the movable member may have a circular shape with their centers aligned, and the electric wire may form a coil wound around the center. In this case, the movable member may be disposed inside the fixed member, or the movable member may be disposed outside the fixed member.

[0021] The disclosed technology also relates to a drive unit for a washing machine.

[0022] The drive unit comprises a drive shaft rotatably supported around a rotation axis, a motor that rotates the drive shaft, and a clutch and a reducer interposed between the drive shaft and the motor, and the clutch has a movable part that slides in the direction of the rotation axis along which the rotation shaft extends, a pair of fixed parts positioned apart in the direction of the rotation axis, and a drive part that switches the connection state of the reducer by sliding the movable part to connect it to one of the fixed parts, and the drive part is constructed using the actuator.

[0023] By using the above-described actuator in the drive section of the clutch that switches the connection state of the reducer, the performance of the washing machine can be improved.

[0024] The drive unit may further include a control device that controls the operation of the clutch, and the control device performs a switching process to connect the movable part to one of the pair of fixed parts by supplying a predetermined switching current to the clutch, and performs a braking process to stop the supply of the switching current to the clutch just before the movable part is connected to one of the fixed parts.

[0025] This makes it possible to effectively suppress impact noise by simply stopping the supply of switching current, that is, by turning off the current.

[0026] The drive unit may further include a control device that controls the operation of the clutch, and the control device executes a switching process to connect the movable part to one of the pair of fixed parts by supplying a predetermined switching current to the clutch, and executes a switching determination process to determine whether the movable part is connected to one of the fixed parts when the switching process is executed.

[0027] Specifically, the control device may execute the switching determination process by comparing the current flowing through the coil with a predetermined determination value immediately after the switching process is executed.

[0028] In such a case, it is preferable that the control device, immediately before executing the switching process, sets the current flowing through the coil based on a predetermined judgment voltage command value as the judgment value, and executes the switching judgment process by comparing the judgment value with the current flowing through the coil based on the judgment voltage command value immediately after the switching process is executed.

[0029] This allows the success or failure of clutch switching to be determined with high accuracy, preventing the occurrence of problems such as abnormal noise caused by poor switching. [Effects of the Invention]

[0030] According to an actuator to which the disclosed technology is applied, reciprocating motion can be performed efficiently and appropriately, so that impact noise can be easily suppressed, for example. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 2 is a schematic cross-sectional view of an actuator. [Figure 2]FIG. 10 is a diagram for explaining the relationship between the state of the actuator and the thrust. [Figure 3] 4 is a diagram showing magnetic flux lines when a movable member is displaced from a first position to a second position. FIG. [Figure 4] 1 is a schematic diagram showing the structure of a washing machine to which the disclosed technology is applied. [Figure 5] FIG. 2 is a schematic side view showing the appearance of the drive unit. [Figure 6] FIG. 2 is an exploded perspective view showing the main components of the drive unit. [Figure 7] FIG. 2 is a schematic cross-sectional view of a main part of a drive unit. [Figure 8] FIG. 2 is a schematic perspective view showing a portion of a shaft and a rotor. [Figure 9] FIG. 2 is a schematic perspective view showing a portion of a stator. [Figure 10] FIG. 2 is a schematic perspective view showing a portion of a reducer. [Figure 11] FIG. 2 is a schematic perspective view showing a portion of a reducer and a clutch. [Figure 12] FIG. 2 is a schematic perspective view showing the main parts of the reducer and the clutch. [Figure 13] FIG. 2 is a schematic perspective view showing the main parts of the reducer and the clutch. [Figure 14] FIG. 10 is a diagram illustrating clutch switching. [Figure 15A] 1 is a flowchart showing an example of a basic operation of a washing machine. [Figure 15B] 10 is a flowchart showing an example of clutch switching. [Figure 16] 10 is a time chart of a braking process. [Figure 17] 10 is a flowchart of a switching determination process. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, embodiments of the disclosed technology will be described in detail with reference to the accompanying drawings. However, the following description is merely exemplary in nature and does not limit the present invention, its applications, or its uses.

[0033] <Actuator> An actuator 100 based on the disclosed technology is illustrated in Figure 1. Figure 1 is a schematic cross-sectional view of the actuator 100.

[0034] The actuator 100 includes a fixed member 110 that is fixed in place when used, and a movable member 120 that reciprocates along the fixed member 110. The movable member 120 reciprocates linearly within a predetermined range in the direction indicated by arrow Y1 in FIG. 1 (first direction). In other words, the actuator 100 is a linear type. The fixed member 110 and the movable member 120 are arranged to face each other with a small gap (gap G) between them in a direction (second direction) that intersects (substantially perpendicular to) the first direction.

[0035] (Fixing member 110) Fixed member 110 is composed of outer core 111, inner core 112, electric wire 113, two magnets 114a, 114b, etc. Outer core 111 and inner core 112 are formed of a soft magnetic material such as a steel plate. Outer core 111 has a pair of support walls 111a, 111a facing each other and spaced apart in a first direction, and connecting walls 111b connected to each end of support walls 111a, 111a that are farther from movable member 120, and is integrally formed so as to have a U-shaped (arch) cross section.

[0036] The opening of the outer core 111 facing the connecting wall portion 111b faces the gap G. Each of the two magnets 114a, 114b has a rectangular cross section and is in close contact with the opposing surface of each support wall portion 111a, along the opening of the outer core 111. The two magnets 114a, 114b are aligned in the first direction.

[0037] These magnets 114a and 114b are magnetized to be oriented in a first direction, and are arranged so that their respective north poles face the first direction. That is, the side of each of the magnets 114a and 114b that faces the support wall 111a is the south pole, and the magnets are arranged so that their north poles face each other.

[0038] Inner core 112 has a rectangular cross section and is disposed between two magnets 114a and 114b in close contact with these magnets 114a and 114b. Two magnets 114a and 114b and inner core 112 are integrated, and the opening of outer core 111 is closed by these.

[0039] As a result, the two magnets 114a, 114b and the inner core 112, together with the ends of both support walls 111a, 111a of the outer core 111, are exposed and face the gap G. These exposed surfaces are formed flat and parallel to the first direction.

[0040] One or more electric wires 113 are housed in the space between these two magnets 114a, 114b and inner core 112, and connecting wall 111b. The more electric wires 113, the better, and since there are usually multiple electric wires, they are referred to as an electric wire group here. The electric wire group extends in a direction that intersects (is substantially perpendicular to) both the first direction and the second direction, that is, in a direction that is substantially perpendicular to the paper surface.

[0041] (movable parts) The movable member 120 has two salient pole cores 120a, 120a, a connecting core 120b, etc., and is integrally formed from a plate-like soft magnetic material. The movable member 120 is formed by bending a steel plate.

[0042] The two salient pole cores 120a extend parallel to each other in the second direction and are arranged side by side at a predetermined interval in the first direction. When the movable member 120 is placed directly opposite the fixed member 110, the tip end portions of each salient pole core 120a are set to face the two magnets 114a and 114b. In this movable member 120, flanges 121 are provided at the tip end portions of the salient pole cores 120a, respectively, which jut out in opposite directions in the first direction.

[0043] The base end portions of these two salient pole cores 120a, 120a, which are located away from the two magnets 114a, 114b, are connected by the connecting core 120b. This gives the cross section of the movable member 120 a so-called hat shape. Note that as long as the connecting core 120b is away from the magnets 114a, 114b, its cross section may be V-shaped or U-shaped.

[0044] (Actuator operation) This actuator 100 is configured such that, when not energized, a magnetic field formed between the movable member 120 and the fixed member 110 generates a driving force that holds the movable member 120 at the first position or the second position.

[0045] Then, by passing a current through the group of electric wires and switching the direction of the current flow (current flow direction), the movable member 120 reciprocates between a first position indicated by a solid line in Fig. 1 and a second position indicated by a two-dot chain line. In other words, switching the current flow direction changes the magnetic field between the movable member 120 and the fixed member 110. This generates a thrust force in the movable member 120, and the thrust force changes according to the displacement.

[0046] 2 shows the relationship between the state of the actuator 100 and the thrust. The horizontal axis represents the position of the movable member 120 relative to the fixed member 110. The vertical axis represents the magnitude of the thrust toward the first position P1 or the second position P2.

[0047] Line L1 represents the change in thrust at each position when no current is applied. Line L2 represents the change in thrust when current is applied from the front toward the paper surface (second current application direction). Line L3 represents the change in thrust when current is applied from the paper surface toward the front (first current application direction). The two-dot chain line L4 will be described later.

[0048] When no current is applied, if the movable member 120 is in the first position P1, a propulsive force toward the first position P1 is generated, and if the movable member 120 is in the second position P2, a propulsive force toward the second position P2 is generated. Therefore, when the movable member 120 is in the first position or the second position, it can be stably held in that position even without current being applied.

[0049] By supplying current in the first current direction, a driving force toward the first position is generated as shown by line L3. By supplying current in the second current direction, a driving force toward the second position is generated as shown by line L2. Therefore, by switching the current direction, the movable member 120 can be reciprocated between the first position and the second position.

[0050] Moreover, the propulsive force generated by energization after the movable member 120 reaches the position (P0, midpoint) directly facing the fixed member 110 can be made smaller than the propulsive force before passing the midpoint. Since the latter half can be displaced gradually, impact noise is suppressed.

[0051] 3 shows magnetic flux lines obtained by magnetic field analysis when the movable member 120 is displaced from the first position to the second position. The lines in each diagram represent magnetic flux. Similarly, arrow B represents the driving force acting on the movable member 120.

[0052] 1(a) shows a state in which the movable member 120 is located at the first position. No current flows through the electric wire 113 (non-energized state). Of the two magnets 114a, 114b of the fixed member 110, a large amount of magnetic flux from the magnet 114a (first magnet 114a) located on the first position side flows through the movable member 120, generating a propulsive force toward the first position, and the movable member 120 is held at the first position.

[0053] 1(b) shows a state in which the movable member 120 is located at the first position. Electricity is passed through the electric wire 113 in a second current-carrying direction. This current weakens the magnetic flux flowing through the movable member 120 by the first magnet 114a. Then, a propulsive force toward the second position is generated by the magnetic force of the magnet 114b (second magnet 114b) located on the second position side, and the movable member 120 is displaced from the first position toward the second position.

[0054] Graph (c) shows a transient state in which the movable member 120 is displaced. The magnetic flux generated by the current and the magnetic flux of the first magnet 114a flow through the core of the fixed member 110 to the movable member 120, increasing the magnetic flux density of the movable member 120. This suppresses the increase in the gap magnetic flux that provides the propulsive force, and the propulsive force gradually decreases. As a result, the movable member 120 is slowly displaced from the first position toward the second position while its acceleration weakens.

[0055] 10(d) shows the state where the movable member 120 has reached the second position. As the magnetic flux density of the movable member 120 increases further, the propulsive force of the movable member 120 decreases, and the movable member 120 is held at the second position.

[0056] Note that when the movable member 120 is displaced from the second position to the first position, it is the same as when it is displaced from the first position to the second position, except that the direction of displacement is reversed, and therefore a description thereof will be omitted.

[0057] (Compared to the conventional configuration) The two-dot chain line L4 in Figure 2 represents the thrust force when the movable member has a magnet (movement-side magnet) (the configuration of the movable member of the clutch in Patent Document 3 mentioned above), for comparison. In this case, the thrust force reaches a maximum near the destination of displacement, and its magnitude is also large. As a result, the momentum of the displacement of the movable member is too strong, generating a loud impact noise.

[0058] In contrast, with this actuator 100, as shown by lines L2 and L3, the thrust decreases in the latter half of the displacement and becomes smaller as the actuator approaches the target position, allowing the momentum of the displacement of the movable member to be moderate. When this actuator 100 was compared with a comparative example under the same conditions, a maximum reduction in thrust of about 50% was observed. Therefore, with this actuator 100, impact noise can be effectively suppressed.

[0059] Furthermore, when the movable member 120 has a mover-side magnet as in the comparative example, there is a risk that the mover-side magnet may come off when the movable member 120 rotates at high speed. In contrast, this actuator 100 does not have a mover-side magnet, so there is no such risk. Therefore, it can rotate at high speed, which is advantageous for dehydration, for example.

[0060] Furthermore, compared to comparable products, this actuator 100 has the advantage of being easier to manufacture. That is, these magnets are typically magnetized after assembling the hard magnetic material, rather than assembling the magnet itself. If the magnet is assembled first, foreign matter such as iron powder may adhere to the magnet or its surroundings during subsequent manufacturing processes, making manufacturing difficult due to the effects of magnetism.

[0061] While the mover magnets for comparison are difficult to magnetize after assembly, the magnets 114a, 114b of this actuator 100 are relatively easy to magnetize after assembly. Therefore, this actuator 100 has the advantage of being easy to manufacture. With this actuator 100, the core (iron core), which is machined with high precision, becomes the main magnetic path for the air gap surface, so it is possible to mitigate non-uniformity in magnetic flux due to variations in magnetization in the core part, and it is also possible to suppress iron loss caused by variations in magnetization.

[0062] Furthermore, in this actuator 100, magnetic flux is less likely to flow in a direction that demagnetizes the magnets 114a and 114b (see the magnetic flux distribution in FIG. 3). Therefore, the demagnetization resistance can be low, and inexpensive magnets can be used for these magnets 114a and 114b. Also, since the movable member 120 can be made only from thin iron plates, the movable member 120 can be made lighter. Less energy is required to displace the movable member 120, and noise can also be reduced.

[0063] <Drive unit for washing machine> Next, an application example of the above-described actuator 100 (a drive unit for a washing machine) will be described.

[0064] Specifically, the actuator 100 is used in the clutch 54 of the drive unit 5, which will be described later. The stator 5432 (fixed member 110) and the mover 5431 (movable member 120) of the clutch 54 (actuator 100) are circular and have the same center, and are formed into an annular shape. The group of electric wires constitutes a clutch coil 5432a wound around the center.

[0065] (washing machine) 4 shows an example of a washing machine 1 to which the actuator 100 is applied. This washing machine 1 is a so-called drum type washing machine. This washing machine 1 is also a so-called fully automatic washing machine, which is configured to automatically perform a series of washing processes including washing, rinsing, spin-drying, etc.

[0066] The washing machine 1 is mainly composed of a housing 2, a tub 3 (fixed tub), a drum 4 (rotary tub), a drive unit 5, a controller 6 (control device), and the like.

[0067] The housing 2 is a box-shaped container made up of panels and a frame, and forms the outer shell of the washing machine 1. A circular loading opening 2a is formed on the front of the housing 2 for loading and unloading laundry. A door 2b with a transparent window is attached to the loading opening 2a. The loading opening 2a is opened and closed by the door 2b. An operating unit 7 having switches and the like to be operated by the user is provided above the loading opening 2a on the housing 2.

[0068] (Tab 3) A tub 3 communicating with the inlet 2a is installed inside the housing 2. The tub 3 is a cylindrical container with a bottom that can store water, and its opening is connected to the inlet 2a. The tub 3 is supported by a damper (not shown) installed inside the housing 2 so that it is stable in a position with its center line J tilted slightly upward toward the front.

[0069] A water supply device 8 consisting of a water supply pipe 8a, a water supply valve 8b, a chemical dispenser 8c, etc. is provided above the tub 3. The upstream end of the water supply pipe 8a protrudes outside the washing machine 1 and is connected to a water supply source (not shown). The downstream end of the water supply pipe 8a is connected to a water supply port 3a that opens at the top of the tub 3. The water supply valve 8b and the chemical dispenser 8c are installed in this order from the upstream side along the water supply pipe 8a.

[0070] The chemical dispenser 8c stores chemicals such as detergent and fabric softener, and dispenses these chemicals into the tub 3 by mixing them with the supplied water. A drain outlet 3b is provided at the bottom of the tub 3. The drain outlet 3b is connected to a drain pump 9. The drain pump 9 discharges unnecessary water that accumulates in the tub 3 to the outside of the washing machine 1 through a drain pipe 9a.

[0071] (Drums 4) The drum 4 is a cylindrical container with a diameter slightly smaller than that of the tub 3, and is housed in the tub 3 with its center line J aligned with that of the tub 3. A circular opening 4a facing the loading port 2a is formed in the front of the drum 4. The laundry is loaded into the drum 4 through the loading port 2a and the circular opening 4a.

[0072] A large number of dewatering holes 4b are formed around the entire circumference of the side of the drum 4 (only some of them are shown in Figure 4). In addition, agitation lifters 4c are attached to multiple locations on the inside of the side. The front of the drum 4 is rotatably supported by the inlet 2a.

[0073] A drive unit 5 is attached to the bottom of the tub 3. As specifically shown in Figures 5 and 6, the drive unit 5 is made up of a shaft 50, a unit base 51, a motor 52, etc. The shaft 50 passes through the rear of the tub 3 and protrudes into the interior of the tub 3. The tip of the shaft 50 is fixed to the center of the bottom of the drum 4.

[0074] That is, the rear part of the drum 4 is journaled by a shaft 50, and the drive unit 5 directly drives the drum 4 (corresponding to a so-called direct drive system). As a result, the drum 4 rotates around the center line J by the drive of the motor 52.

[0075] The center line J corresponds to the rotation axis (rotation axis J). Because this washing machine 1 is a drum type, the rotation axis J is disposed so as to extend in a direction inclined with respect to the horizontal direction or in a substantially horizontal direction.

[0076] The controller 6 is installed on the top of the housing 2. The controller 6 is composed of hardware such as a CPU and memory, and software such as a control program and various data. The controller 6 comprehensively controls the operation of the washing machine 1.

[0077] An inverter 10 that receives power from an external power source is installed inside the housing 2. The inverter 10 is electrically connected to the controller 6 and the drive unit 5. The controller 6 controls the inverter 10 to drive the drive unit 5, which then rotates the drum 4.

[0078] <Drive unit 5> As described above, the drive unit 5 is made up of the shaft 50, the unit base 51, the motor 52, etc. A schematic cross-sectional view of the main part of the drive unit 5 is shown in FIG.

[0079] As shown in FIG. 6, the unit base 51 is made of a substantially disk-shaped metal or resin member attached to the bottom of the tub 3. A cylindrical shaft insertion hole 511 extending along the center line J is formed in the center of the unit base 51. A pair of ball bearings (a main bearing 512M and a sub-bearing 512S) are attached to both ends of the shaft insertion hole 511. In FIG. 6, the shaft 50 and the sub-bearing 512S are shown assembled to the motor 52. The motor 52 is assembled to the back side of the unit base 51.

[0080] The shaft 50 is made of a cylindrical metal member with a diameter smaller than that of the shaft insertion hole 511. The shaft 50 is inserted into the shaft insertion hole 511 with its tip portion protruding from the shaft insertion hole 511. The shaft 50 is supported by the unit base 51 via a pair of ball bearings 512M, 512S. This allows the shaft 50 to rotate around the rotation axis J.

[0081] This motor 52 is designed to have a structure suitable for driving the washing machine 1. That is, the washing machine 1 performs the washing, rinsing, and spin-drying processes. For this purpose, the motor 52 is required to have a high torque output at low rotation speeds and a low torque output at high rotation speeds.

[0082] Generally, a system is used in which a reducer and clutch are placed between the drum and the motor to indirectly rotate the drum (indirect drive system), or a system is used in which the motor is driven by an inverter to directly rotate the drum (direct drive system).

[0083] In contrast, this drive unit 5 is designed to efficiently combine the indirect drive system and the direct drive system to eliminate the drawbacks of each system. In other words, this washing machine 1 can achieve a large washing capacity in a compact size, low noise, and energy savings.

[0084] Specifically, a motor 52 that rotates a single shaft 50, which is an output shaft, is efficiently incorporated with a reducer 53 and a clutch 54 that are interposed between the shaft 50 and the motor 52, thereby forming an integrated structure. As a result, the motor 52, reducer 53, and clutch 54 are aligned in a line in a direction substantially perpendicular to the rotation axis J. These structures will be described in detail below.

[0085] (Base end portion 50a of shaft 50) As shown in Fig. 7, the base end 50a of the shaft 50 protrudes from the sub-bearing 512S. A threaded hole 501 extending along the center line J is formed in the base end 50a of the shaft 50. Serrations extending along the center line J are formed on the outer circumferential surface of the base end 50a of the shaft 50 (see Fig. 10). A bolt 503 is fastened to the threaded hole 501 via a fastener 502. In this way, a main frame 5311 of a carrier 531 (described later) is fixed to the base end 50a of the shaft 50.

[0086] (Motor 52) The motor 52 has a rotor 521 and a stator 522. The motor 52 is a so-called outer rotor type in which the rotor 521 is located outside the stator 522.

[0087] As shown in FIG. 8, rotor 521 is composed of rotor case 5211, a plurality of magnets 5212, and the like. Rotor case 5211 is made of a cylindrical member with a bottom, the center of which is aligned with rotation axis J. Rotor case 5211 has disk-shaped bottom wall 5211a with a circular hole in the center, and cylindrical peripheral wall 5211b continuing around bottom wall 5211a. Bottom wall 5211a may be made of multiple pieces or a single piece. Rotor case 5211 has a shallow bottom (small thickness), and the height of peripheral wall 5211b is smaller than the radius of bottom wall 5211a.

[0088] A cylindrical bearing portion 5211c is formed around a round hole that opens at the center of the bottom wall 5211a, facing the peripheral wall 5211b. A gear is formed on the outer circumferential surface of the bearing portion 5211c, and the bearing portion 5211c also serves as a sun gear (sun gear 5211c) that will be described later.

[0089] A cylindrical sintered oil-impregnated bearing 5213 is fixed to the inside of the shaft support portion 5211c. The shaft support portion 5211c is slidably supported on the shaft 50 (more specifically, on a main frame 5311 fixed to the shaft 50) via this sintered oil-impregnated bearing 5213. This allows the rotor case 5211 to rotate relative to the shaft 50. The sintered oil-impregnated bearing 5213 constitutes a rotor bearing portion.

[0090] Each magnet 5212 is made of a rectangular permanent magnet 114 bent into an arc shape. The magnets 5212 are fixed to the inner surface of the peripheral wall 5211b of the rotor case 5211 so as to be lined up in series in the circumferential direction. Each magnet 5212 constitutes a magnetic pole of the rotor 521, and is arranged so that the south pole and the north pole are alternately arranged.

[0091] 9, stator 522 is made of an annular member and has an annular core portion 522a and a plurality of teeth 522b protruding radially outward from core portion 522a. Stator 522 is fixed to unit base 51 via fixing flange portion 522c provided inside core portion 522a. Stator 522 is housed in rotor case 5211.

[0092] Core portion 522a and each tooth portion 522b are formed by covering the surface of stator core 5221 made of magnetic metal with an insulating insulator. Although not shown, multiple coils are formed by winding conductive wire around each tooth portion 522b in a predetermined order. A portion of stator core 5221 is exposed at the end face of each tooth portion 522b located on the outer periphery of stator 522. These exposed portions of stator core 5221 face magnets 5212 of rotor 521 in the radial direction, with a predetermined gap G between them.

[0093] The multiple coils form three-phase coil groups consisting of U, V, and W. The controller 6 controls the inverter 10 to supply alternating current to each of these coil groups while shifting the phase. This creates a magnetic field between each coil group and the magnetic poles of the rotor 521. The magnetic force causes the rotor 521 to rotate around the rotation axis J.

[0094] (Reducer 53) The reducer 53 is disposed around the bearing portion 5211c. The reducer 53 is housed in the rotor case 5211. Fig. 10 shows the reducer 53. The reducer 53 is a reducer that uses a so-called planetary gear mechanism, and is composed of a carrier 531, a sun gear 5211c, a plurality of (four in the illustrated example) planetary gears 533, an internal gear 534, and the like.

[0095] The carrier 531 has a main frame 5311 and a sub-frame 5312. The sub-frame 5312 is an annular member having four lower bearing recesses 5312a. The sub-frame 5312 is mounted on the rotor case 5211 via an annular guide plate 535.

[0096] A ring-shaped sliding member 536 is fixed to the inside of guide plate 535. Guide plate 535 is rotatably mounted on bottom wall 5211a of rotor case 5211 with sliding member 536 interposed between guide plate 535 and pivot support portion 5211c.

[0097] The main frame 5311 has a base 5311a in the shape of a shallow cylinder with a bottom, and a cylindrical shaft stopper 5311b protruding from the center of the base 5311a to the back side. The back side of the base 5311a is disposed to face the sub-frame 5312. A plurality of upper bearing recesses 5311c are formed on the back side of the base 5311a, each facing one of the lower bearing recesses 5312a.

[0098] Serrations that fit onto the base end 50a of the shaft 50 are formed on the inner peripheral surface of the shaft stopper 5311b. By inserting the base end 50a of the shaft 50 into the shaft stopper 5311b, the main frame 5311 is fixed to the shaft 50 in an unrotatable state. As described above, the shaft support 5211c of the rotor 521 is supported around the shaft stopper 5311b via the sintered oil-impregnated bearing 5213 that forms the rotor bearing. This shaft support 5211c forms the sun gear that rotates about the rotation axis J.

[0099] The internal gear 534 is made of a substantially cylindrical member with a larger diameter than the sun gear 5211c. A gear portion 534a is provided on the lower part of the inner peripheral surface of the internal gear 534. Gear teeth are formed on the gear portion 534a all around. In addition, a plurality of inner slide guides 534b, each consisting of linear protrusions extending in the direction of the rotation axis, are formed at equal intervals all around the outer peripheral surface of the internal gear 534. These inner slide guides 534b will be described separately below.

[0100] The internal gear 534 is disposed around the sun gear 5211c with the rotation axis J as the center. The lower part of the internal gear 534 is disposed on a guide plate 535. A ring-shaped sliding member 537 is fixed to the inside of the upper part of the internal gear 534 (see FIG. 7). The carrier 531 (main frame 5311) is rotatably supported by the internal gear 534 via this sliding member 537.

[0101] Each planetary gear 533 is rotatably supported by the carrier 531, and is disposed between the sun gear 5211c and the internal gear 534 so as to mesh with them.

[0102] Each planetary gear 533 is made of a small-diameter gear member. A pin hole is formed through the center of each planetary gear 533. Both ends of a pin 5331 inserted into the pin hole are journaled in an upper bearing recess 5311c of the main frame 5311 and a lower bearing recess 5312a of the sub-frame 5312. Gear teeth are formed around the entire outer periphery of each planetary gear 533. These gear teeth mesh with both the sun gear 5211c and the internal gear 534.

[0103] Therefore, when the sun gear 5211c rotates at a predetermined speed while the internal gear 534 is fixed (unrotatable), each planetary gear 533 rotates while orbiting the sun gear 5211c, causing the carrier 531 and the shaft 50 to rotate at a reduced speed.

[0104] (Clutch 54) The clutch 54 is disposed around the reducer 53. The clutch 54 is housed in a rotor case 5211. Figures 11, 12, and 13 show the reducer 53 and the clutch 54. The clutch 54 has a slider 541 (movable part), rotor-side and stator-side lock claws 542R, 542S (fixed parts), and a clutch driver 543 (drive part).

[0105] The clutch driver 543 has a mover 5431 and a stator 5432. The mover 5431 and the stator 5432 are configured using the actuator 100 described above.

[0106] The slider 541 is made of a cylindrical member with a larger diameter than the internal gear 534. On the inner peripheral surface of the slider 541, as only a portion of it is shown in Figure 11, a plurality of outer slide guides 541a made of linear protrusions extending in the direction of the rotation axis are formed at equal intervals around the entire circumference. These outer slide guides 541a are configured to mesh with a plurality of inner slide guides 534b formed on the outer peripheral surface of the internal gear 534.

[0107] The slider 541 is disposed around the internal gear 534 with its outer slide guides 541a meshing with the inner slide guides 534b of the internal gear 534. This allows the slider 541 to slide in the direction of the rotation axis.

[0108] A pair of engagement claws 5411R, 5411S, each consisting of a rotor-side and stator-side engagement claw, is formed on the outer circumferential surface of slider 541. These engagement claws 5411R, 5411S are made up of multiple protrusions (movable-side protrusions) protruding in the rotational axis direction, and are formed at equal intervals around the entire outer circumferential surface of slider 541. Rotor-side engagement claw 5411R is disposed at the lower end of slider 541, with each protrusion protruding downward. Stator-side engagement claw 5411S is disposed at the upper end of slider 541, with each protrusion protruding upward.

[0109] A mover accommodating portion 541b for accommodating the mover 5431 is formed on the outer circumferential surface of the slider 541 between the engaging claws 5411R and 5411S on the rotor side and the stator side.

[0110] As shown in Figure 13, rotor-side locking claw 542R is provided on an annular member 544 attached to rotor case 5211. Rotor-side locking claw 542R is composed of multiple protrusions (fixed-side protrusions) that protrude in the direction of the rotation axis at equal intervals around the entire circumference. These protrusions protrude upward. Although not shown, these protrusions can be formed simultaneously with other components during integral molding of the rotor side, or can be formed integrally with rotor case 5211.

[0111] The stator-side locking claw 542S is provided on an annular member 545 attached to the stator 522. The stator-side locking claw 542S is composed of a plurality of protrusions (fixed-side protrusions) that protrude in the direction of the rotation axis at equal intervals around the entire circumference. These protrusions protrude downward. These protrusions can also be formed integrally with the insulator.

[0112] The rotor-side locking claw 542R and the stator-side locking claw 542S are arranged to face each other at positions spaced apart in the direction of the rotation axis. The rotor-side locking claw 542R is configured to mesh with the rotor-side engaging claw 5411R, and the stator-side locking claw 542S is configured to mesh with the stator-side engaging claw 5411S.

[0113] The distance between rotor-side locking claw 542R and stator-side locking claw 542S is set larger than the distance between rotor-side engagement claw 5411R and stator-side engagement claw 5411S. Therefore, when rotor-side locking claw 542R engages with rotor-side engagement claw 5411R to be coupled, stator-side locking claw 542S does not engage with stator-side engagement claw 5411S. When stator-side locking claw 542S engages with stator-side engagement claw 5411S to be coupled, rotor-side locking claw 542R does not engage with rotor-side engagement claw 5411R.

[0114] 12, the mover 5431 of the clutch driver 543 has the movable member 120. The movable member 120 is installed in the mover accommodating portion 541b.

[0115] 13, the stator 5432 of the clutch driver 543 has a fixed member 110. That is, it is made up of a clutch coil 5432a, an inner core 112, an outer core 111, two magnets 114a and 114b, and the like.

[0116] Outer core 111 is composed of a pair of upper and lower annular holders 5432c. Holders 5432c are fixed to stator 522. Inner core 112 and two magnets 114a, 114b are both formed in an annular shape. Movable member 120 is configured to be positioned inside fixed member 110 and to face fixed member 110 with a small radial gap G between them.

[0117] The supply of current to the clutch coil 5432a is controlled by the controller 6. When the controller 6 supplies a switching current, that is, currents having opposite current directions, to the clutch coil 5432a, the movable member 120 is displaced linearly relative to the fixed member 110. As a result, the controller 6 executes a process (switching process) of sliding the slider 541 in either direction of the rotation axis.

[0118] This switches between a first mode in which the stator side locking claws 542S and the stator side engaging claws 5411S engage, and a second mode in which the rotor side locking claws 542R and the rotor side engaging claws 5411R engage, as shown in FIG.

[0119] In the first mode, the internal gear 534 is supported by the stator 522 via the slider 541. As a result, the rotation of the rotor 521 and the sun gear 5211c is transmitted to the shaft 50 and the carrier 531 via the reducer 53. Therefore, the drive unit 5 outputs a high torque rotational force at a low rotation speed.

[0120] On the other hand, in the second mode, the internal gear 534 is supported by the rotor 521 via the slider 541. As a result, the rotation of the rotor 521 and the sun gear 5211c is transmitted to the shaft 50 and the carrier 531 without going through the reducer 53.

[0121] That is, the rotor 521, the sun gear 5211c, and the internal gear 534 rotate together, and therefore the planetary gears 533 do not orbit. As a result, the shaft 50 and the carrier 531 also rotate together with these. Therefore, the drive unit 5 outputs a rotational force with high rotation speed and low torque.

[0122] Thus, with this drive unit 5, the motor 52, the reducer 53, and the clutch 54 are efficiently incorporated into the motor 52 and configured as an integrated unit so that they are aligned in a direction substantially perpendicular to the rotation axis J. Then, by switching the clutch 54, it is possible to output a rotational force with low rotation speed and high torque, and a rotational force with low torque but high rotation speed, through the single shaft 50. Furthermore, even in both the first mode and the second mode, which have different outputs, the rotation speed and torque values ​​of the motor 52 can be set to relatively similar values, thereby optimizing motor efficiency.

[0123] Therefore, the drive unit 5 is compact in size and can output a rotational force suitable for a washing machine. The drive unit 5 is suitable for a washing machine.

[0124] (Washing machine 1 operation) FIG. 15A shows an example of a basic operation of the washing machine 1.

[0125] When the washing machine 1 is operated, laundry is first loaded into the drum 4 (Step S1). In the case of this washing machine 1, detergent and the like are also loaded into the chemical dispenser 8c at this time. Then, a command to start washing is input to the controller 6 by operating the operation unit 7 (Yes in Step S2). In response, the controller 6 automatically starts a series of washing processes including washing, rinsing, and spin-drying.

[0126] Prior to the washing step, the controller 6 measures the weight of the laundry in order to set the amount of water to be supplied (step S3). The controller 6 sets an appropriate amount of water to be supplied based on the measured weight of the laundry (step S4).

[0127] Once the amount of water to be supplied has been set, the controller 6 starts the washing process (step S5). When the washing process starts, the controller 6 controls the water supply valve 8b to supply the set amount of water to the tub 3. At this time, the detergent contained in the chemical supply device 8c is supplied to the tub 3 together with the supplied water.

[0128] Next, the controller 6 drives the drive unit 5 to start rotating the drum 4. At this time, prior to rotating the drum 4, the controller 6 determines whether the washing or rinsing process is in progress (step S10), as shown in Fig. 15B. If the washing or rinsing process is in progress, the controller 6 controls the clutch 54 to switch to the first mode (step S11). If the washing or rinsing process is not in progress, i.e., if the spin-drying process is in progress, the controller 6 controls the clutch 54 to switch to the second mode (step S12).

[0129] Since the washing step is being performed here, the controller 6 switches the clutch 54 to the first mode, which causes the drive unit 5 to output a high torque rotational force at a low speed. This allows the relatively heavy drum 4 to be rotated efficiently at a low speed.

[0130] When the washing step is completed, the controller 6 starts the rinsing step (step S6). In the rinsing step, the drain pump 9 is driven to drain the washing water accumulated in the tub 3. Next, the controller 6 performs the water supply and stirring processes in the same manner as in the washing step.

[0131] In the rinsing step, the drive unit 5 is driven with the clutch 54 maintained in the first mode.

[0132] After the rinsing cycle is completed, the controller 6 executes the spin cycle (step S7). In the spin cycle, the drum 4 is driven to rotate at high speed for a predetermined time. Therefore, the controller 6 switches the clutch 54 to the second mode prior to the spin cycle. In the second mode, a rotational force with high rotation speed and low torque can be output. Therefore, the drum 4, which is relatively light, can be rotated efficiently at high speed.

[0133] The laundry is stuck to the inner surface of the drum 4 by centrifugal force, and the water contained in the laundry flows out of the drum 4. As a result, the laundry is dehydrated.

[0134] Water that accumulates in tub 3 during spin-drying is drained by driving drain pump 9. When the spin-drying process is completed, a predetermined buzzer sounds to notify the user that washing has finished, and operation of washing machine 1 ends.

[0135] (Impact noise suppression control by drive unit) In this washing machine 1, the control is devised so that the impact noise can be suppressed by utilizing the structure of the clutch driver 543, more specifically, the actuator 100.

[0136] Specifically, the controller 6 executes a switching process, and executes a process (braking process) to stop the supply of switching current to the clutch 54 immediately before the slider 541 is connected to the locking claws 542R, 542S.

[0137] 16 shows a time chart of the braking process. Graph G1 represents the change in current flowing through the clutch 54. Graph G2 represents the speed of the slider 541. Graph G3 represents the thrust of the slider 541. MP is the target position where the locking claws 542R, 542S and the engaging claws 5411R, 5411S mesh with each other (corresponding to the first position and the second position).

[0138] At a predetermined timing before the slider 541 reaches the target position MP, the controller 6 turns off the power supply to the clutch coil 5432a. Even when the power supply to the clutch coil 5432a is turned off, the slider 541 continues to move due to inertia and the magnetic force of the magnet. By turning off the power supply to the clutch coil 5432a, the speed of the slider 541 is suppressed by a sudden decrease in the propulsive force and braking by the regenerative current. This makes it possible to suppress impact noise.

[0139] This can be easily controlled by simply stopping the supply of switching current to the clutch 54. By simply adjusting the timing of stopping, impact noise can be effectively suppressed.

[0140] (Clutch switching determination control by drive unit) If the switching process fails, for example, because the clutch 54 is not switched or is switched but not in the appropriate position, and the motor 52 is driven in that state, problems such as abnormal noise and damage to the clutch 54 may occur. Therefore, it is preferable to determine the success or failure of each switching process.

[0141] In contrast, this washing machine is further devised to control the clutch driver 543, more specifically, by utilizing the structure of the actuator 100, so that it is possible to determine whether the clutch 54 has been switched successfully.

[0142] Specifically, the controller 6 compares the current flowing through the clutch coil 5432a with a predetermined determination value immediately after the switching process is executed, thereby executing a process (switching determination process) for determining whether the switching of the clutch 54 has been successful.

[0143] When current flows in the same direction before and after the switching process, the magnetic flux density between the movable member 120 and the fixed member 110 differs. This causes a difference in inductance, which changes the transient response of the current. Based on this change, the success or failure of the switching process can be determined.

[0144] Specifically, as shown in (b) of Figure 3, when current is applied before the switching process, the magnetic flux generated by the current in the movable member 120 acts to weaken the magnetic flux of the magnet 114. Therefore, the magnetic flux density is low. In contrast, as shown in (d) of Figure 3, when current is applied after the switching process, the direction of the magnetic flux of the current and the direction of the magnetic flux of the magnet 114 are the same. Therefore, the magnetic flux density is high.

[0145] This causes a difference in inductance before and after the switching process, which in turn causes a change in the transient response of the current. Based on this change, the controller 6 determines whether the switching process has been successful.

[0146] The judgment value may be set to a predetermined value in advance, but it is preferable to energize clutch coil 5432a based on a predetermined judgment voltage command value immediately before executing the switching process, and set the current flowing through clutch coil 5432a as the judgment value.

[0147] The judgment value may be affected by external factors such as the ambient temperature and the usage state of the clutch 54. However, if the judgment value is set in this manner each time the switching judgment process is performed, such influences can be eliminated, and the switching judgment process can be performed with high accuracy.

[0148] Then, the switching determination process can be performed by comparing the determination value with the current flowing through the clutch coil 5432a based on the determination voltage command value immediately after the switching process is performed.

[0149] An example of such a switching determination process is shown in Fig. 17. When starting the switching process, immediately before that, the controller 6 energizes the clutch coil 5432a based on a predetermined voltage command value for determination (a voltage command value that causes a current of a magnitude that does not affect the state of the clutch 54 to flow). By doing so, the controller 6 obtains a current value Ia flowing through the clutch coil 5432a and sets the current value Ia as a determination value (step S20).

[0150] Specifically, a predetermined voltage is applied for a short period of several milliseconds during which the clutch 54 cannot respond. For example, the voltage may be applied in the form of PWM modulated with a carrier frequency of several tens of kilohertz using an inverter, or in the form of a single pulse.

[0151] Next, the controller 6 executes a switching process (step S21), which displaces the slider 541 and switches the clutch 54 to either the first mode or the second mode.

[0152] In order to determine whether the clutch 54 has been switched appropriately, the controller 6 energizes the clutch coil 5432a based on the same determination voltage command value as above, and obtains a current value Ib for comparison (step S22).The controller 6 then compares whether the current value Ib is greater than a determination value Ia (step S23).

[0153] As can be seen from the analysis results in Figure 3, the magnetic field generated by the current flowing through the clutch coil 5432a forms a magnetic path by passing mainly through the iron cores of the movable and fixed parts, which have low magnetic permeability and low magnetic resistance. In the configuration of the present invention, as described above, the magnetic flux density when current flows in the same direction varies depending on the position of the clutch rotor. The soft magnetic material used in the iron core has the property that as the magnetic flux density increases, the magnetic permeability decreases and the magnetic resistance increases. By utilizing this property, the magnetic resistance when current is applied changes depending on the position of the clutch 54, so the impedance of the clutch coil 5432a changes, and the transient response of the current when voltage is applied changes.

[0154] As a result, if the current value Ib is greater than the judgment value Ia, it is determined that the switching of the clutch 54 has been successful (step S24). If the current value Ib is equal to or less than the judgment value Ia, it is determined that the switching of the clutch 54 has failed, and a retry is performed (step S25). Note that, although the case where the current value Ib is determined to be successful when it is greater than the judgment value Ia has been shown here, if the direction of the current flow at the time of switching is reversed, the magnitude relationship between the current value Ib and the judgment value Ia will be reversed.

[0155] If the absolute values ​​of the current values ​​Ia and Ib (|Ia|, |Ib|) are used for the judgment, it becomes possible to judge based only on the magnitude relationship of the numerical values, regardless of the direction of the current flow. Also, to prevent erroneous judgments, the judgment value Ia obtained first can be multiplied by a coefficient, such as ``|Ib| > |Ia| × coefficient,'' so that it is not judged as successful unless the judgment value Ib obtained later exceeds this coefficient.

[0156] According to this drive unit 5, it is possible to appropriately determine each time whether the clutch 54 has been switched successfully, and therefore it is possible to prevent problems caused by improper switching of the clutch 54.

[0157] The disclosed technology is not limited to the above-described embodiment, but also includes various other configurations.

[0158] For example, in the embodiment, the magnets are arranged so that their north poles face each other, but they may also be arranged so that their south poles face each other. By reversing the direction of current flow to the coils, the same effects as in the embodiment can be obtained. Furthermore, the fixed member 110 may have three or more magnets. The movable member 120 may be arranged inside or outside the fixed member 110. [Explanation of symbols]

[0159] 100 Actuators 110 Fixing member 112 Inner Core 113 Electric wire 114a, 114b magnet 120 Movable parts 120a salient pole core 120b connected core 1 washing machine 3 Tab (fixed tank) 4 Drum (rotating tank) 5 Drive unit 6 Controller (control device) 52 Motor 53 Reducer 533 Planetary Gear 534 Internal Gear 54 Clutch 541 Slider (moving part) 5411R Rotor side engagement claw 5411S Stator side engagement claw 542R Rotor side locking claw (fixed part) 542S Stator side locking claw (fixed part) 543 Clutch driver (drive unit) 5431 Mover 5432 Stator 5432a clutch coil J Center line (rotation axis) G Gap

Claims

1. An actuator including a fixed member that is fixed in place and a movable member that reciprocates along the fixed member in a predetermined first direction, The fixing member is an electric wire positioned apart from the movable member in a second direction intersecting the first direction and extending in a direction intersecting both the first direction and the second direction; two magnets arranged between the electric wire and the movable member in a state aligned in the first direction, and arranged such that the same magnetic poles of each magnet face each other in the first direction; an inner core closely integrated between the magnets so that magnetic flux can flow; an outer core having a pair of support walls that are spaced apart and opposed to each other in the first direction, with the magnets closely contacting each other on their opposing surfaces, and integrally formed with the outer core via a connecting wall that allows magnetic flux to flow; and The movable member is two salient pole cores arranged side by side in the first direction, each having a tip portion that faces the two magnets across a gap; a connecting core connecting base end portions of the two salient pole cores at a position spaced apart from the two magnets; and An actuator in which the movable member reciprocates by switching the direction of current flow in the electric wire.

2. 2. The actuator according to claim 1, the movable member is integrally formed using a plate-shaped soft magnetic material, An actuator in which a flange portion that projects in a direction opposite to the first direction is provided at each tip end portion of the salient pole core.

3. 3. The actuator according to claim 1, the fixed member and the movable member have a circular shape with their centers aligned, The actuator has a coil wound around the center by the electric wire.

4. 4. The actuator according to claim 3, An actuator in which the movable member is disposed inside the fixed member.

5. 4. The actuator according to claim 3, An actuator in which the movable member is disposed outside the fixed member.

6. A drive unit for a washing machine, comprising: a drive shaft supported rotatably about a rotation axis; a motor that rotates the drive shaft; a clutch and a reducer interposed between the drive shaft and the motor; Equipped with The clutch is a movable portion that slides in a rotation axis direction along which the rotation axis extends; a pair of fixing portions positioned apart in the direction of the rotation axis; a drive unit that switches the connection state of the reducer by sliding the movable unit to connect it to one of the fixed units; and A drive unit, wherein the drive section is configured using the actuator according to any one of claims 3 to 5.

7. 7. The drive unit according to claim 6, Further, a control device for controlling the operation of the clutch is provided. A drive unit in which the control device performs a switching process to connect the movable part to one of the pair of fixed parts by supplying a predetermined switching current to the clutch, and performs a braking process to stop the supply of the switching current to the clutch just before the movable part is connected to one of the fixed parts.

8. 7. The drive unit according to claim 6, Further, a control device for controlling the operation of the clutch is provided. A drive unit in which the control device executes a switching process to connect the movable part to one of the pair of fixed parts by supplying a predetermined switching current to the clutch, and also executes a switching determination process to determine whether the movable part is connected to one of the fixed parts when the switching process is executed.

9. 9. The drive unit according to claim 8, The control device executes the switching determination process by comparing the current flowing through the coil with a predetermined determination value immediately after the switching process is executed.

10. 10. The drive unit according to claim 9, the control device sets the current flowing through the coil based on a predetermined voltage command value for determination as the determination value immediately before executing the switching process, and executes the switching determination process by comparing the determination value with the current flowing through the coil based on the voltage command value for determination immediately after the switching process is executed.

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