KR102176372B1 - Electric motor capable of switching windings - Google Patents

Abstract

The present invention relates to a winding-switchable electric motor, wherein a stator coil includes a plurality of winding units capable of being connected in series or parallel to each other, and a fixed terminal unit configured to connect the plurality of winding units in series or parallel to one side of the stator coil, and A changeover switch having a movable terminal part which is arranged to be movable relative to the fixed terminal part so that the plurality of winding parts are selectively connected in series or in parallel is connected, and a rotation speed of the rotation shaft is set in advance at one side of the changeover switch. When the speed is reached, a driving unit for driving the movable terminal unit is provided. Thereby, the use of expensive semiconductor switches can be eliminated and cost can be reduced.

Description

ELECTRIC MOTOR CAPABLE OF SWITCHING WINDINGS}

The present invention relates to an electric motor.

As is well known, an electric motor is a device that converts electrical energy into mechanical energy. The electric motor is classified into an AC motor and a DC motor according to the type of power source. The electric motor is configured with a stator (stator) and a mover (mover, rotor) disposed to be able to move relative to the stator.

The stator of the electric motor includes a stator core and a stator coil wound around the stator core. In recent years, electric vehicles using the electric motor as a power source are increasing. The motor for driving a vehicle used in the electric vehicle requires a relatively large torque when starting, and a high-speed driving when driving.

In consideration of this point, some of the stator coils are provided with a plurality of winding units configured to enable series connection and parallel connection to each other, and a winding switching device for switching windings such that the plurality of winding units are connected in series or in parallel. When a plurality of windings are connected in series or in parallel, a winding-switchable electric motor is used to improve operation efficiency.

However, in such a conventional winding-switchable motor, a winding-switching system including an expensive switching element similar to an inverter is configured for winding-switching, thereby increasing manufacturing cost.

In addition, such a conventional winding switching system has a problem in that a switch-on loss of a plurality of switching elements occurs, resulting in a decrease in overall operation efficiency.

KR 10-0702911 B1

Accordingly, an object of the present invention is to provide a winding-switchable electric motor capable of reducing cost by eliminating the use of expensive semiconductor switches.

In addition, another object of the present invention is to provide a winding-switchable electric motor capable of improving operation efficiency by suppressing occurrence of switch-on loss.

In addition, another object of the present invention is to provide a winding-switchable electric motor capable of easily switching windings during high-speed rotation while excluding the use of an expensive semiconductor switch at an inexpensive price.

In the winding-switchable electric motor according to the present invention for solving the above-described problems, the stator coil includes a plurality of winding units that can be connected in series or parallel to each other, and the plurality of winding units are in series or on one side of the stator coil. A changeover switch having a fixed terminal part to be connected in parallel and a movable terminal part which is arranged to be movable relative to the fixed terminal part so that the plurality of winding parts are selectively connected in series or in parallel is connected, and at one side of the changeover switch It is a technical feature that a driving unit for driving the movable terminal unit is provided when the rotational speed of the rotating shaft reaches a preset set speed.

Specifically, the plurality of winding portions include a first winding portion and a second winding portion, and the fixed terminal portion of the switching switch includes: a first terminal portion configured to connect the first winding portion and the second winding portion in series with each other; And a second terminal portion connecting the first winding portion and the second winding portion in parallel with each other.

The movable terminal portion includes: a first connection terminal portion in contact with the first terminal portion to connect the first terminal portion to be energized; A second connection terminal portion in contact with the second terminal portion to connect the second terminal portion to be energized; And an action rod connecting the first connection terminal portion and the second connection terminal portion.

Here, the fixed terminal part and the movable terminal part, when the first connection terminal part is connected to the first terminal part, the second connection terminal part and the second terminal part are separated from each other, and the second connection terminal part and the second terminal part When connected, the first connection terminal portion and the first terminal portion are configured to be separated from each other.

According to an embodiment of the present invention, the driving unit includes: a centrifugal weight provided to be rotatable along a radial direction on the rotation shaft; And a slider that is moved in the axial direction of the rotation shaft by the centrifugal weight when the centrifugal weight is rotated on one side of the centrifugal weight, wherein the movable terminal part is configured to be moved by a slider that is moved by the centrifugal weight. do.

The centrifugal weight is composed of a pair arranged to face each other, the centrifugal weight composed of the pair is provided with a return spring for returning the centrifugal weight to the initial position.

The movable terminal portion includes a first connection terminal portion connecting the first terminal portion to be energized and a second connection terminal portion connecting the second terminal portion to be energized.

The movable terminal portion is configured to be movable between a serial connection position to which the first terminal portion and the first connection terminal portion are connected and a parallel connection position to which the second terminal portion and the second connection terminal portion are connected.

On the other hand, according to another embodiment of the present invention, the drive unit may include an action member that moves along a radial direction by a centrifugal force when the rotation shaft rotates; A pressure sensing unit that is in contact with the working member to sense pressure; And an actuator for operating the changeover switch when the rotation shaft reaches a preset set speed based on a pressure detection result of the pressure sensing unit.

A body which is integrally rotatably coupled to the rotation shaft and has an accommodation space formed therein is provided on the rotation shaft, and the action member is accommodated and installed in the accommodation space of the body.

The actuator is implemented as an electric actuator when power is applied.

More specifically, the actuator may include a coil generating magnetic force when power is applied; A fixed core provided on one side of the coil; And a movable core disposed to be approached and spaced apart from the fixed core, and a movable core rod integrally coupled to the movable core.

When a magnetic force is generated by the coil when power is applied to the coil, the movable core rod is moved together along the moving direction of the movable core when the movable core is moved to approach the fixed core.

An elastic member is provided inside the receiving space of the body to press the action member against centrifugal force.

Here, the elastic member may be implemented as a compression coil spring.

The body is provided with a movement inhibiting unit that suppresses excessive compression of the pressure sensing unit by the action member when the rotation shaft is rotated.

Here, the pressure sensing unit may be configured to be elastically deformed along the thickness direction, and may be pressed by the action member to be compressed in the thickness direction. The movement restraining part is provided on at least one side of the pressure sensing part and configured to prevent excessive compression of the pressure sensing part by the action member.

A support part receiving and supporting the pressure sensing part is detachably coupled to the body.

In the body, a coupling portion to which the support portion is coupled is recessed, and the support portion is configured to be insertedly coupled to the coupling portion.

The body and the support are configured to be screwed together.

The elastic member is configured to be expandable and contractible along the moving direction of the acting member.

One end of the elastic member is configured to be supported by contacting the interior of the receiving space of the body, and the other end of the elastic member is configured to be supported by contacting the support.

As described above, according to an embodiment of the present invention, a switching switch for connecting a plurality of windings of a stator coil in series or in parallel is provided with a plurality of terminal portions and a movable terminal portion, thereby using an expensive semiconductor switch. Can be excluded, manufacturing cost can be reduced.

In addition, since the winding changeover switch is configured without a semiconductor switch, it is possible to suppress the occurrence of switch-on loss and to suppress a decrease in overall operating efficiency due to the occurrence of switch-on loss. Accordingly, the operating efficiency of the electric motor can be improved.

In addition, since the drive unit for driving the winding changeover switch is configured to be driven using a centrifugal force generated by a preset set speed when the rotor rotates, the configuration of the drive unit can be simplified.

In addition, the driving unit includes an acting member that is moved radially by a centrifugal force when the rotation shaft is rotated, a pressure sensing unit for sensing the pressure of the working member, and an actuator for operating a switching switch based on the detection result of the pressure sensing unit. By being provided and configured, the configuration is simple at low cost, and it is possible to easily switch the winding of the stator coil even when the rotating shaft rotates at high speed.

1 is a cross-sectional view of a winding-switchable electric motor according to an embodiment of the present invention,
FIG. 2 is a diagram schematically showing a connection state of a stator coil and a changeover switch of the electric motor of FIG. 1;
3 is a view showing the inside of the changeover switch of FIG. 1;
4 is a view for explaining the operation of the switching switch of FIG. 3;
5 is a cross-sectional view of a winding-switchable electric motor according to another embodiment of the present invention,
6 is a cross-sectional view of the drive unit of FIG. 5;
7 is a view for explaining the operation of the drive unit of FIG. 6;
8 is a view showing the inside of the actuator of FIG. 5;
9 is a view for explaining the action of the actuator of FIG. 8;
10 is a control block diagram of the electric motor of FIG. 5.

Hereinafter, exemplary embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings. In the present specification, the same/similar reference numerals are assigned to the same/similar configurations even in different embodiments, and the description is replaced with the first description. Singular expressions used in the present specification include plural expressions unless the context clearly indicates otherwise. In addition, in describing the embodiments disclosed in the present specification, if it is determined that a detailed description of related known technologies may obscure the subject matter of the embodiments disclosed in the present specification, the detailed description thereof will be omitted. In addition, it should be noted that the accompanying drawings are for easy understanding of the embodiments disclosed in the present specification and should not be construed as limiting the technical idea disclosed in the present specification by the accompanying drawings.

1 is a cross-sectional view of a winding-switchable electric motor according to an embodiment of the present invention. As shown in FIG. 1, the winding-switchable electric motor of the present invention includes a stator 150, a rotor 250, a changeover switch 300, and a drive unit 400.

A housing or frame 110 (hereinafter, referred to as'frame 110') is provided outside the stator 150. The frame 110 is configured such that an accommodation space is formed therein. The frame 110 includes, for example, a cylindrical portion 120 having an accommodation space formed therein, and a bracket 130 coupled to block an opening of the cylindrical portion 120.

The tubular portion 120 may be configured to have both sides open, for example. The brackets 130 are respectively coupled to both sides of the tubular portion 120. The cylindrical portion 120 may have an inner shape corresponding to the outer shape of the stator 150. In this embodiment, a case in which the outer surface of the stator 150 is formed in a circular shape and the cylindrical portion 120 is implemented in a cylindrical shape is exemplified, but is not limited thereto.

The stator 150 includes a stator core 160 and a stator coil 180 wound around the stator core 160. The stator core 160 may be configured by insulatingly stacking a plurality of electrical steel sheets 162, for example. A plurality of slots 164 and teeth 166 are formed in the electrical steel plate 162 of the stator core 160. The electrical steel plate 162 of the stator core 160 has a circular shape, and the plurality of slots 164 and teeth 166 are formed alternately with each other along an outer circumferential surface. The plurality of slots 164 are formed through the electrical steel plate 162 along the axial direction. A rotor receiving hole is formed through the center of the stator core 160 so that the rotor 250 can be accommodated with a predetermined air gap 240 therebetween.

The rotor 250 includes a rotation shaft 251 and a rotor core 260 rotated around the rotation shaft 251. The rotor core 260 may be formed by insulating laminated electrical steel sheets 262, for example. The electrical steel sheet 262 of the rotor core 260 is formed in a circular shape. A rotation shaft hole 264 into which the rotation shaft 251 is inserted is formed through the center of the electrical steel plate 262 of the rotor core 260. The rotor core 260 is provided with a plurality of conductor bars 266 inserted in the axial direction and spaced apart in the circumferential direction, for example. Short-circuit rings 267 are provided at both ends of the rotor core 260 to connect the plurality of conductor bars 266 to each other. The plurality of conductor bars 266 connected by the short ring 267 form a closed circuit.

The rotation shaft 251 is formed to protrude toward both sides of the rotor core 260. Both sides of the rotation shaft 251 are rotatably supported. Bearings 255 are respectively coupled to both sides of the rotation shaft 251. The bearings 255 are respectively coupled to the bearing coupling portions 135 provided in the bracket 130. In this embodiment, a case in which the rotor 250 is implemented as a so-called induction rotor with a plurality of conductor bars 266 is illustrated, but this is only an example, and the rotor 250 is different from each other along the circumferential direction. It may be configured with permanent magnets in which magnetic poles are alternately formed.

2 is a diagram schematically showing a connection state of a stator coil and a changeover switch of the electric motor of FIG. 1. As shown in FIG. 2, the stator coil 180 is configured with a plurality of phase-specific winding units 190 connected to each phase of the power supply. Here, the power source is composed of a three-phase (U-phase, V-phase, W-phase) AC power supply. The power may be configured to be provided by, for example, an inverter 210. The inverter 210 may convert, for example, DC power input from a vehicle battery into 3-phase AC power and provide it. A cable 215 outputting three-phase power is provided at one side of the inverter 210. The cables 215 of the inverter 210 are respectively connected to a power input terminal of the stator coil 180.

Each of the plurality of phase-specific winding units 190 of the stator coil 180 includes a first winding unit and a second winding unit that can be connected in series or in parallel with each other.

More specifically, the stator coil 180 includes a U-phase winding unit 190U, a V-phase winding unit 190V, and a W-phase winding unit 190W respectively connected to a three-phase (U-phase, V-phase, W-phase) power supply. Equipped. The U-phase winding unit 190U includes a first winding unit (a first U-shaped winding unit 190U1) and a second winding unit (a second U-shaped winding unit) that can be connected in series or parallel to each other. The V-phase winding unit 190V includes a first winding unit (a first V-phase winding unit 190V1) and a second winding unit (a second V-phase winding unit 190V2) that can be connected in series or parallel to each other. The W-phase winding unit 190W includes a first winding unit (a first W upper winding unit 190W1) and a second winding unit (a second W upper winding unit 190W2) that can be connected in series or parallel to each other.

To one side of the stator coil 180, each of the first winding portions 190U1, 190V1, 190W1 and the second winding portions 190U2, 190V2, 190W2 of the same phase (U phase, V phase, W phase) are selectively series A switching switch 300 for connecting or connecting in parallel is provided. In the electric motor of the present embodiment, when the first winding portions 190U1, 190V1, 190W1 and the second winding portions 190U2, 190V2, 190W2 of the stator coil 180 are connected in series with each other, a torque is increased. The speed is reduced. In the electric motor of this embodiment, when the first winding portions 190U1, 190V1, 190W1 and the second winding portions 190U2, 190V2, 190W2 of the stator coil 180 are connected in parallel with each other, the torque decreases and the speed increases. . Accordingly, when the electric motor of this embodiment is used to drive a vehicle, driving efficiency can be improved.

The winding-switchable motor of this embodiment, when reaching a set speed set at around 95% (±2%) of the rated speed, the first winding unit 190U1, 190V1, 190W1 and the second winding unit 190U2, 190V2, 190W2) are configured to be switched in parallel with each other. More specifically, in the electric motor of this embodiment, the set speed may be configured such that the first winding part and the second winding part are switched in parallel with each other at 93% to 97% of the rated speed, for example. Here, the rated speed of the electric motor of this embodiment may be set within 10,000 rpm from several thousand rpm, for example. When the rated speed of the electric motor of the present embodiment is, for example, 4000 rpm, the stator coil 180 may be configured to be connected in parallel with the first winding part and the second winding part at about 3800 rpm (3720 to 3880 rpm).

3 is a view showing the inside of the changeover switch of FIG. 1, and FIG. 4 is a view for explaining the operation of the changeover switch of FIG. 3 and 4, the switching switch 300 includes a fixed terminal part 320 and a fixed terminal part 320 for selectively connecting the first winding part and the second winding part in series or parallel to each other. ) And a movable terminal portion 340 disposed to be movable relative to each other so that the first winding portion and the second winding portion are selectively connected to each other in series or parallel.

The fixed terminal part 320 includes: a first terminal part 321 for connecting the first winding part and the second winding part in series with each other; And a second terminal portion 322 connecting the first winding portion and the second winding portion in parallel with each other. The first terminal portion 321 and the second terminal portion 322 are electrically connected to each other by the first winding portion and the second winding portion and a connection line 360. The connection line 360 includes a first connection line 361 connecting the first terminal part 321 and the stator coil 180, and a second connection line 361 connecting the second terminal part 322 and the stator coil 180 A connection line 362 is provided.

The first terminal portion 321 includes a first U upper terminal portion 321U1, a first V upper terminal portion 321V1, and a first W upper terminal portion 321W1 disposed spaced apart from each other. The first U upper terminal part 321U1 is electrically connected to one side (right end of the drawing) of the second U upper winding part 190U2 by the first connection line 361. The first V upper terminal portion 321V1 is electrically connected to one side (right end of the drawing) of the second V upper winding portion 190V2 by the first connection line 361. The first W upper terminal part 321W1 is electrically connected to one side (right end of the drawing) of the second W upper winding part 190W2 by the first connection line 361.

The second terminal portion 322 includes a second U upper terminal portion 322U2, a second V upper terminal portion 322V2, and a second W upper terminal portion 322W2 disposed spaced apart from each other. The second U upper terminal portion 322U2 is electrically connected to a connection line between the first U upper winding unit 190U1 and the second U upper winding unit 190U2 by the second connection line 362. The second V upper terminal portion 322V2 is electrically connected to a connection line between the first V upper winding unit 190V1 and the second V upper winding unit 190V2 by the second connection line 362. The second W upper terminal portion 322W2 is electrically connected to a connection line between the first W upper winding portion 190W1 and the second W upper winding portion 190W2 by the second connection line 362.

The movable terminal part 340 may include a first connection terminal part 341 in contact with the first terminal part 321 to connect the first terminal part 321 to be energized; A second connection terminal portion 342 in contact with the second terminal portion 322 to connect the second terminal portion 322 to be energized; And an action rod 350 integrally connecting the first connection terminal portion 341 and the second connection terminal portion 342.

The first terminal portion 321 and the second terminal portion 322 are configured with a plurality of contact points 325 spaced apart from each other, respectively. The first connection terminal portion 341 and the second connection terminal portion 342 connect each of the plurality of contact points 325 of the first terminal portion 321 and the second terminal portion 322 formed spaced apart from each other for each phase so as to be energized. Each of the plurality of connecting pieces 3450 may be provided. Each of the plurality of connecting pieces 345 is implemented in a rod or plate shape.

Here, the fixed terminal part 320 and the movable terminal part 340 are, when the first connection terminal part 341 is connected to the first terminal part 321, the second connection terminal part 342 and the second terminal part ( 322 is separated from each other, and when the second connection terminal portion 342 and the second terminal portion 322 are connected, the first connection terminal portion 341 and the first terminal portion 321 are preset to be separated from each other. It is configured to be spaced apart by distance.

The changeover switch 300 includes a case 310 accommodating the first terminal portion 321 and the second terminal portion 322 and the movable terminal portion 340. One end of the action rod 350 protrudes from one side of the case 310 (left side in the drawing). The other end of the action rod 350 is movably accommodated on the other side (right side in the drawing) of the case 310. The other side of the case 310 is provided with an elastic member 358 for pressing the action rod 350 in the longitudinal direction. The elastic member 358 may be implemented as, for example, a compression coil spring. The action rod 350 is provided with a contact piece 357 in contact with the elastic member. An elastic member receiving part 315 in which the elastic member 358 is accommodated is formed on the other side of the case 310. The movable terminal portion 340 is located at a serial connection position where the first winding portion and the second winding portion are connected in series by the elastic force of the elastic member 358 (see FIG. 3). When the motor of this embodiment is stopped, the movable terminal part 340 is present in a serial connection position by the elastic force of the elastic member 358, and the stator coil 180 has a first winding part and a second winding part in series with each other. Is connected to. Accordingly, a relatively large torque is generated when the electric motor is started, so that starting is facilitated, and operation efficiency can be improved.

At one side of the changeover switch 300, when the rotation shaft 251 reaches a preset set speed, a driving unit 400 that drives the movable terminal part 340 so that the first winding part and the second winding part are connected in parallel. Is equipped. When the first winding part and the second winding part are connected in parallel by the driving unit 400, the input (current) of the stator coil 180 may be reduced, thereby improving driving efficiency.

Referring back to FIG. 1, the drive unit 400 includes a centrifugal weight 410 provided to be rotatable along a radial direction on the rotation shaft 251; And a slider 440 which is moved in the axial direction of the rotation shaft 251 by the centrifugal weight 410 when the centrifugal weight 410 rotates on one side of the centrifugal weight 410.

The drive unit 400 includes a centrifugal weight support part 420 that supports the centrifugal weight 410 so as to be rotatable by a centrifugal force. The centrifugal weight support part 420 includes a rotation shaft coupling part 422 into which a rotation shaft 251 is inserted and coupled, and a guide 425 extending outward from the rotation shaft coupling part 422. The rotation shaft coupling portion 422 is constrained with respect to the rotation direction of the rotation shaft 251 and is coupled to be movable along the axial direction. The rotation shaft coupling portion 422 and the rotation shaft 251 may have, for example, male and female splines meshed with each other in a rotational direction in a mutual contact area, respectively. The rotation shaft coupling portion 422 has, for example, a cylindrical shape. In this embodiment, a case where the rotation shaft coupling part 422 and the rotation shaft 251 are provided with a sprang-in part that meshes with each other is illustrated, but this is only an example, and the rotational direction in the mutual contact area It may be configured with a serration.

The guides 425 are formed respectively protruding from the outer surface of the rotation shaft coupling portion 422 in a direction perpendicular to the rotation shaft 251. The guide 425 is implemented in a cantilever shape. The guides 425 are formed in pairs to protrude in opposite directions to each other on both sides of the rotation shaft coupling part 422. At the end of the guide 425, a separation prevention part 427 is formed to prevent separation of the centrifugal weight 410. The departure prevention part 427 is, for example, the guide 425 so as to be in contact with the centrifugal weight 410 moved outward along the guide 425 to suppress the movement of the centrifugal weight 410 ) Is formed to protrude horizontally in the longitudinal direction.

The centrifugal weight 410 is implemented in a substantially triangular shape. The centrifugal weight 410 is formed in a pair. The centrifugal weight 410 is formed with a through portion 415 to allow the guide 425 to pass (see FIG. 4 ). A return spring 417 for returning the centrifugal weight 410 to the initial position is provided between the pair of centrifugal weights 410. The return spring 417 is implemented as, for example, a tension spring. The return spring 417 may be provided on both sides of the centrifugal weight 410, respectively. The return spring 417 is coupled to the centrifugal weight 410 in a state in which both ends are pulled so that a preset tensile force can act. Each end of the return spring 417 is formed on the centrifugal weight 410 so that each end of the return spring 417 can be engaged.

A slider 440 is provided on one side of the centrifugal weight 410. The slider 440 is formed to be movable along the axial direction of the rotation shaft 251. The slider 440 includes a rotation shaft receiving portion 445 coupled to pass through the rotation shaft 251 and a collar 448 extending in a radial direction at one side of the rotation shaft receiving portion 445. . A centrifugal weight coupling portion 446 into which one end of the centrifugal weight 410 is inserted and coupled is formed on an outer surface of the rotating shaft receiving portion 445. The centrifugal weight 410 and the centrifugal weight coupling part 446 are formed to be constrained with respect to the axial direction of the rotation shaft 251. Accordingly, when the centrifugal weight 410 rotates by the centrifugal force when the rotation shaft 251 rotates, the slider 440 may be moved along the axial direction by the centrifugal weight 410. The centrifugal weight coupling part 446 is formed to be opened radially outward of the rotation shaft 251.

On one side of the collar 448, an action rod 350 of the changeover switch 300 is disposed to be contactable. The action rod 350 may include, for example, a bent end portion 355 that is horizontally bent in the moving direction of the slider 440. The bent end portion 355 of the action rod 350 is disposed to contact the collar 448. In this embodiment, the moving direction of the working rod 350 is arranged parallel to the moving direction of the slider 440, and a bent end 355 is formed at the end of the working rod 350, so that the working rod 350 ) Is configured to be pulled, but this is only an example, and the drive unit 400 and the changeover switch 300 are operated by the drive unit 400 and the action rod 350 of the changeover switch 300 It may be configured to be moved by being pressed (pushed).

With this configuration, before starting the operation, the first winding portion and the second winding portion of the stator coil 180 are connected in series by the changeover switch 300. When the operation is started and power is applied to the stator coil 180, the rotor 250 is rotated around the rotation shaft 251 by a rotating magnetic field formed by the stator coil 180. At this time, since the first and second windings of the plurality of phase-specific windings 190 of the stator coil 180 are connected in series, respectively, a relatively large torque is output. As a result, starting can be facilitated and operation efficiency can be improved.

When time elapses, the rotational speed of the rotor 250 increases, and when the rotational speed of the rotational shaft 251 reaches a preset set speed, the centrifugal force of the centrifugal weight 410 of the driving unit 400 increases. The elastic force (tensile force) of the return spring 417 is exceeded, and accordingly, the centrifugal weight 410 is rotated along the radial direction. One side of the centrifugal weight 410 is moved outward along the guide 425, and the other side of the centrifugal weight 410 is moved along the axial direction of the rotation shaft 251. Accordingly, the slider 440 is moved along the axial direction of the rotation shaft 251.

When the slider 440 is moved along the axial direction by the rotation of the centrifugal weight 410, as shown in FIG. 4, the action rod 350 of the switching switch 300 is pulled and moved in the axial direction. do. Accordingly, the first connection terminal portion 341 is spaced apart from the first terminal portion 321, and the second connection terminal portion 342 is in contact with the second terminal portion 322 so that the second terminal portion 322 It is connected to be energized. Accordingly, the first winding portion and the second winding portion of the phase-specific winding portion 190 of the stator coil 180 are disconnected from each other in series and are connected in parallel with each other. Accordingly, the rotor 250 maintains high-speed rotation while reducing the input of the stator coil 180, thereby improving the driving efficiency of the electric motor.

Hereinafter, another embodiment of the present invention will be described with reference to FIGS. 5 to 10. 5 is a cross-sectional view of a winding-switchable electric motor according to another embodiment of the present invention. The winding-switchable electric motor of this embodiment includes a stator 150, a rotor 250, a changeover switch 300, and a drive unit 500.

A frame 110 is provided outside the stator 150. The frame 110 is configured with a tubular portion 120 and a bracket 130.

The stator 150 includes a stator core 160 and a stator coil 180 wound around the stator core 160. Inside the stator 150, the rotor 250 is rotatably accommodated with a predetermined air gap.

The rotor 250 includes a rotation shaft 251, a rotor core 260 rotated around the rotation shaft 251, and a plurality of conductor bars 266 provided in the rotor core 260.

The stator coil 180 includes a plurality of phase-specific winding units 190 respectively connected to each phase (U phase, V phase, W phase) of the power supply. The plurality of phase-specific winding units 190 are configured with a first winding unit and a second winding unit selectively connected in series or parallel to each other.

The winding-switchable electric motor of the present embodiment may be configured with a rated speed of 10,000 rpm to tens of thousands of rpm, for example.

At one side of the stator coil 180, a switching switch 300 for switching the first winding portions 190U1, 190V1, 190W1 and the second winding portions 190U2, 190V2, 190W2 of the stator coil 180 in series or parallel. ) Is provided.

The changeover switch 300 includes a first terminal portion 321 for connecting the first winding portions 190U1, 190V1, 190W1 and the second winding portions 190U2, 190V2, 190W2 in series with each other, and the first winding Between the second terminal portion 322 and the first terminal portion 321 and the second terminal portion 322 to allow the unit (190U1, 190V1, 190W1) and the second winding portion (190U2, 190V2, 190W2) to be connected in parallel with each other The first terminal portion 321 and the second terminal portion 322 are arranged to be movable and include a movable terminal portion 340 that selectively connects the second terminal portion 322.

On the other hand, at one side of the changeover switch 300, when the rotation speed of the rotation shaft 251 reaches a preset set speed, the first winding unit 190U1, 190V1, 190W1 and the second winding unit 190U2, 190V2, 190W2 ) Is provided with a driving unit 500 for driving the movable terminal unit 340 to be connected in parallel with each other.

6 is a cross-sectional view of the drive unit of FIG. 5, and FIG. 7 is a view for explaining the operation of the drive unit of FIG. 6. As shown in FIG. 6, the driving unit 500 includes, for example, an action member 550 that is moved along a radial direction by centrifugal force when the rotation shaft 251 rotates; A pressure sensing unit 560 disposed so as to be in contact with the working member 550 to sense a pressure when the rotation shaft 251 rotates; And an actuator 570 that operates the changeover switch 300 when the rotation shaft 251 reaches a preset set speed based on the pressure detection result of the pressure detection unit 560.

The driving unit 500 includes a body 510 that guides the movement of the working member 550. The body 510 may be provided to be rotatable integrally with the rotation shaft 251, for example. The body 510 may be formed of, for example, a synthetic resin member, and may be integrally fixedly coupled to the rotation shaft 251. The body 510 is configured in a cylindrical shape, for example. An accommodation space 512 is formed inside the body 510. The accommodation space 512 is formed along the radial direction of the body 510. The accommodation space 512 of the body 510 may be formed to be open to the outside along a radial direction, for example. The receiving space 512 is formed to accommodate the working member 550 therein to guide the working member 550 to slide along the radial direction of the body 510.

Inside the body 510, a pressure sensing unit 560 is provided in contact with the working member 550 to sense pressure. The pressure sensing unit 560 may be configured to be elastically deformed along the moving direction of the acting member 550. When the pressure sensing unit 560 is in contact with the working member 550, it is pressed by the working member 550 and may be configured to be contracted in the thickness direction. The pressure sensing unit 560 is provided with a signal line 562 to output a sensing signal to the outside when the pressure is sensed. The pressure sensing unit 560 may be configured to detect a change in the centrifugal force acting on the acting member 550 according to an increase in the rotational speed of the rotation shaft 251.

According to this configuration, the mass of the acting member 550 does not need to be large, and it may be desirable that the mass of the acting member 550 be small as long as detection precision is ensured. If the mass of the working member 550 is small, the sensing capacity of the pressure sensing unit 560 can be reduced by that amount, and the sizes of the working member 550 and the body 510 can be reduced together, so that the driving unit ( 500), the overall manufacturing cost can be reduced. In addition, in the driving unit 500 of this embodiment, since the mass of the working member 550 is relatively small, the rotation shaft 251 rotates at high speed (for example, 5,000 rpm to tens of thousands of rpm). At the time, since the magnitude of the centrifugal force generated by the working member 550 is relatively small, the support strength of the body 510 for supporting the working member 550 is relatively small, so the configuration can be made at low cost. .

The body 510 is provided with a support part 515 for receiving and supporting the pressure sensing part 560. The support part 515 may be configured to be detachable from the body 510. The support part 515 may be configured to be coupled to the body 510 to block the opening of the receiving space 512. The support part 515 has a width that is wider than the width of the opening of the receiving space 512. The support part 515 may be configured to be screwed to the body 510, for example. A receiving part 517 into which the pressure sensing part 560 is inserted is formed in the support part 515. On the outer edge of the receiving part 517, a movement inhibiting part 518 is formed in contact with the working member 550 to suppress the movement of the working member 550. Thereby, the pressure sensing unit 560 is suppressed from being excessively compressed by the acting member 550, thereby preventing the occurrence of damage to the pressure sensing unit 560 due to excessive compression of the pressure sensing unit 560. Can be suppressed.

An elastic member 530 is provided inside the body 510 to press the action member 550 against centrifugal force. The elastic member 530 may be implemented as, for example, a compression coil spring. When the elastic member 530 is accommodated inside the receiving space 512, it is slightly compressed and may be accommodated in a state in which elastic force is accumulated. Thereby, when the rotation shaft 251 is stopped, the working member 550 is pressed by the elastic member 530 and is disposed at a position (initial position) moved toward the rotation shaft 251.

With this configuration, when the rotation shaft 251 is rotated, it is integrally rotated with the body 510. As the rotational speed of the rotation shaft 251 increases, the centrifugal force acting on the working member 550 increases, and as the centrifugal force of the working member 550 increases, the elastic member is compressed so that the working member 550 Is moved to. When the working member 550 comes into contact with the pressure sensing unit 560, as shown in FIG. 7, the pressure sensing unit 560 is elastically deformed to contract in the thickness direction and senses the pressure. When the rotational speed of the rotation shaft 251 is increased and the centrifugal force is increased, the action member 550 is in contact with the movement restraining unit 518 to inhibit movement, whereby the pressure sensing unit 560 is prevented from excessive compression. The occurrence of resulting damage can be prevented.

Meanwhile, the actuator 570 for driving the movable terminal unit 340 is provided at one side of the changeover switch 300. The actuator 570 includes an electric actuator 570 that generates a driving force when power is applied. The actuator 570 is implemented as a solenoid.

FIG. 8 is a view showing the inside of the actuator of FIG. 5, and FIG. 9 is a view for explaining the operation of the actuator of FIG. 8. As shown in FIG. 8, the actuator 570 includes a coil 572 generating magnetic force when power is applied; A fixed core 574 provided on one side of the coil 572; A movable core 577 that is disposed to be approached and spaced apart from the fixed core 574; And a movable core rod 581 integrally coupled to the movable core 577. The fixed core 574 and the movable core 577 are composed of a magnetic material.

A yoke 571 is provided outside the coil 572. The yoke 571 is formed of a magnetic material to form a magnetic path. The yoke 571 has a substantially rectangular parallelepiped shape. The fixed core 574 is provided inside the coil 572. The movable core 577 is spaced apart from one side of the fixed core 574. The fixed core 574 and the movable core 577 are spaced apart so as to be accessible from each other along the axial direction. The movable core rod 581 is provided at the center of the movable core 577. The movable core rod 581 is coupled to pass through the center of the fixed core 574. A movable core rod receiving portion 575 is formed through the fixed core 574 so that the movable core rod 581 can be movably received. The movable core rod 581 protrudes to one side of the yoke 571. At the end of the movable core rod 581 protruding to the outside of the yoke 571, a locking protrusion 583 is provided so as to be constrained in the axial direction with the bent end 355 of the movable terminal portion 340 of the changeover switch 300 do.

One side of the movable core 577 is provided with an elastic member 579 for pressing the movable core 577 in the axial direction. The elastic member 579 is implemented as, for example, a compression coil spring. The elastic member 579 is compressed when the movable core 577 is moved toward the fixed core 574 to accumulate elastic force. Here, the magnetic force generated by the coil 572 not only compresses the elastic member 579, but also the changeover switch 300 connected to the action rod 350 connected to the movable core rod 581. By compressing the elastic member 358 of the movable terminal portion 340 may be configured to a degree that can be moved to the parallel connection position and/or higher.

With this configuration, when power is applied to the coil 572, magnetic flux passing through the inside of the coil 572 is generated. The fixed core 574 forms a magnetic path. The fixed core 574 is magnetized. Accordingly, the movable core is moved to approach the fixed core 574, as shown in FIG. 9.

On the other hand, when the supply of power to the coil 572 is stopped, the magnetic force generated by the coil 572 is extinguished, and the movable core 577 is the fixed core due to the accumulated elastic force of the elastic member 579. It returns to the initial position separated from (574).

10 is a control block diagram of the electric motor of FIG. 5. As shown in FIG. 10, the winding-switchable motor of the present embodiment includes a control unit 600 implemented as a microprocessor with a control program. The control unit 600 is configured to adjust the frequency of power during speed adjustment. A speed control unit 610 for adjusting the rotational speed of the electric motor is communicatively connected to the control unit 600. An inverter 210 is controllably connected to the controller 600 to adjust the frequency of the power input to the stator coil 180 based on an input signal from the speed controller 610.

On the other hand, when the rotation speed of the rotation shaft 251 reaches a preset set speed, the control unit 600 controls the driving unit 500 so that the first winding part and the second winding part of the stator coil 180 are connected in parallel with each other. ) Is configured to be able to control.

More specifically, when the rotation shaft 251 reaches a set speed set at around 95% (±2%) of the rated speed, the control unit 600 controls the first and second windings of the stator coil 180. It can be configured to control to be connected in parallel with each other. The controller 600 controls the actuator 570 so that the first and second windings of the stator coil 180 are connected in parallel when the rotational speed of the rotation shaft 251 reaches a preset set speed. It is structured to be able to.

The pressure sensing unit 560 is communicatively connected to the control unit 600 to detect pressure when the rotational speed of the rotation shaft 251 is increased. The actuator 570 is controllably connected to the controller 600 to control the movable terminal 340 of the changeover switch 300 when the rotational speed of the rotation shaft 251 reaches a preset set speed. .

The control unit 600 may be configured to store and store in advance a rotational speed of the rotational shaft 251 when the rotational shaft 251 rotates and a corresponding pressure value of a centrifugal force acting on the acting member 550 corresponding thereto. . The control unit 600 may be configured to calculate the rotational speed of the rotation shaft 251 based on the pressure value sensed by the pressure sensing unit 560.

The controller 600 controls the actuator 570 when the rotation speed of the rotation shaft 251 calculated by the calculation unit is less than the set speed, and the movable terminal part 340 of the changeover switch 300 is connected in series. Can be moved to a location.

With this configuration, when the operation is stopped, the switching switch 300 is present in the serial connection position, which is the initial position of the movable terminal part 340 by the elastic force of the elastic member 358. Accordingly, the stator coil 180 is connected in series with each of the first and second winding portions of the plurality of phase-specific winding portions 190. When power is input to the stator coil 180 from the inverter 210, the stator coil 180 forms a rotating magnetic field, and the rotor 250 is rotated around the rotation shaft 251 by electromagnetic induction. .

When time elapses, the rotational speed of the rotation shaft 251 increases, and the centrifugal force acting on the action member 550 increases. The working member 550 is moved outward along the radial direction, and the pressure sensing unit 560 is contracted by the working member 550 to sense pressure. When the rotational speed of the rotational shaft 251 reaches the set speed by the pressure sensing unit 560, the control unit 600 controls the actuator 570 to control the movable terminal part 340 of the changeover switch 300. Is moved to the parallel connection position. When the movable terminal unit 340 is moved to the parallel connection position, each of the first and second winding units of the plurality of phase-specific winding units 190 of the stator coil 180 are connected in parallel to each other. Accordingly, the rotor 250 maintains a normal operating speed while reducing the current input to the stator coil 180, thereby improving the driving efficiency of the electric motor.

On the other hand, the control unit 600 controls the power supply of the coil 572 of the actuator 570 to be stopped when the rotational speed of the rotation shaft 251 is reduced below the set speed. Thereby, the movable core rod 581 of the actuator 570 is returned to the initial position by the elastic force of the elastic member 579, and the movable terminal portion 340 of the changeover switch 300 is formed of the elastic member 358. It is moved to the series connection position by the elastic force. Accordingly, the stator coil 180 is connected in series with each of the first winding portions and the second winding portions of the plurality of phase-specific winding portions 190, respectively.

In the above, it has been shown and described with respect to specific embodiments of the present invention. However, the present invention may be implemented in various forms within a range not departing from its spirit or essential features, and thus the above-described embodiments should not be limited by the content of the detailed description.

In addition, even if the embodiments are not listed in detail in the above-described detailed description, they should be broadly interpreted within the scope of the technical idea defined in the appended claims. In addition, all changes and modifications included within the technical scope of the claims and their equivalents should be covered by the appended claims.

Claims (10)

A stator having a stator core having a plurality of slots and a stator coil wound through the plurality of slots; And
Including; a rotor disposed rotatably with respect to the stator about a rotation axis,
The stator coil includes a plurality of phase-specific winding units connected to each phase of the power supply,
The plurality of phase-specific winding units each have a first winding unit and a second winding unit that can be connected in series or parallel to each other,
At one side of the stator coil, a first terminal portion for connecting the first winding portion and the second winding portion in series, a second terminal portion for connecting the first winding portion and the second winding portion in parallel, and the first terminal portion; A changeover switch that is arranged to be movable between the second terminal portions and has a movable terminal portion selectively connecting the first terminal portion and the second terminal portion, and switches the first winding portion and the second winding portion in series or parallel Is connected,
A winding, characterized in that, at one side of the switching switch, a driving unit is provided to drive the movable terminal part so that the first winding part and the second winding part are connected in parallel to each other when the rotational speed of the rotation shaft reaches a preset set speed. Switchable electric motor. The method of claim 1,
The driving unit may include a centrifugal weight provided to be rotatable along a radial direction on the rotation shaft; And a slider that is moved in the axial direction of the rotating shaft by the centrifugal weight when the centrifugal weight is rotated on one side of the centrifugal weight, and
A winding switchable electric motor, wherein the movable terminal portion is moved by the slider. The method of claim 2,
The centrifugal weight is composed of a pair arranged to face each other, the winding switchable electric motor, characterized in that it further comprises a return spring to return the centrifugal weight to the initial position. The method of claim 1,
The movable terminal part includes a first connection terminal part for energizing the first terminal part and a second connection terminal part for energizing the second terminal part, and the first terminal part and the first connection terminal part are connected to each other. A winding switchable motor, characterized in that it is movable between a series connection position and a parallel connection position to which the second terminal part and the second connection terminal part are connected. The method of claim 1,
The driving unit,
A body integrally rotatably coupled to the rotating shaft and having an accommodation space formed therein;
An action member accommodated in the receiving space and moved along a radial direction when the rotation shaft rotates;
A pressure sensing unit disposed to be in contact with the working member to sense a pressure when the rotating shaft rotates; And
And an actuator that operates the changeover switch when the rotation shaft reaches a preset set speed based on a pressure detection result of the pressure sensing unit. The method of claim 5,
The actuator may include a coil generating magnetic force when power is applied; A fixed core provided on one side of the coil; And a movable core disposed to be approached and spaced apart from the fixed core, and a movable core rod integrally coupled to the movable core. The method of claim 5,
A winding switchable electric motor, characterized in that the body is provided with an elastic member for pressing the working member against centrifugal force. The method of claim 7,
A winding switchable electric motor, characterized in that a support part receiving and supporting the pressure sensing part is detachably coupled to the body. The method of claim 8,
One end of the elastic member is supported inside the receiving space of the body, and the other end of the elastic member is supported by the support part. The method of claim 5,
A winding switchable electric motor, wherein the body is provided with a movement restraining unit that suppresses excessive compression of the pressure sensing unit by the acting member when the rotation shaft is rotated.

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