Motors and motor units

Abstract

For example, to provide a motor that can switch the connection method of multiple coils within a single circuit. [Solution] For example, a motor (100, 200) comprising a circuit (10) having a first coil (11), a second coil (12), and a first switching element (13) connected to the first coil (11) and the second coil (12), wherein the circuit (10) corresponds to a first phase, and the first switching element (13) can switch the connection between the first coil (11) and the second coil (12) between a parallel connection and a series connection.

Description

Technical Field

[0001] The present invention relates to a motor and a motor unit.

Background Art

[0002] In a brushless DC motor or the like, there is known one having a plurality of coils corresponding to one phase (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] If it is possible to switch the connection method of a plurality of coils within one circuit for each phase, the versatility of the motor is improved and it is also advantageous in terms of cost. An example of the problem of the present invention is to provide a motor capable of switching the connection method of a plurality of coils within one circuit.

Means for Solving the Problems

[0005] The motor of the present invention includes a circuit having a first coil, a second coil, and a first switching element connected to the first coil and the second coil. The circuit corresponds to a first phase, and the first switching element can switch the connection between the first coil and the second coil between a parallel connection and a series connection.

Brief Description of the Drawings

[0006] [Figure 1] It is a cross-sectional view along the rotation axis of the motor according to one embodiment. [Figure 2] It is a cross-sectional view along the radial direction of the motor according to one embodiment. [Figure 3]This diagram shows that in a motor according to one embodiment, the motor drive control device controls the switching elements of the circuits corresponding to each phase. [Figure 4] This diagram shows that in a motor according to one embodiment, multiple circuits are connected in a Y-connection (star connection). [Figure 5] This diagram shows that in a motor according to another embodiment, multiple circuits are connected in a delta configuration. [Modes for carrying out the invention]

[0007] In describing embodiments of the present invention, for convenience of explanation, the direction along the rotor's rotation axis X (rotation axis direction) is simply referred to as the rotation axis direction. In the rotation axis direction, the direction of arrow a in Figure 1 is referred to as one side, and the direction of arrow b, which is the opposite direction, is referred to as the other side. In a plane perpendicular to the rotation axis X, the direction approaching or moving away from the rotation axis X is referred to as the radial direction. In the radial direction, the direction of arrow c, moving away from the rotation axis X, is referred to as the outside or one side, and the direction of arrow d, moving towards the rotation axis X, is referred to as the inside or the other side. In a certain member or part, the outer surface in the radial direction (direction of arrow c) may be referred to as the outer circumferential surface, and the inner surface in the radial direction (direction of arrow d) may be referred to as the inner circumferential surface. The direction of rotation around the rotation axis X is referred to as the circumferential direction.

[0008] The overall configuration of a motor according to an embodiment of the present invention will be described below with reference to the drawings. The overall configuration of the motor shown below is merely one example of the overall configuration of the motor of the present invention. For example, the motor of the present invention may be an inner rotor type motor as illustrated below, an inner rotor type motor having other configurations, or an outer rotor type motor. Furthermore, the motor of the present invention may be, for example, a brushless DC motor, or another type of motor.

[0009] Figure 1 is a cross-sectional view of the motor 100 according to this embodiment along the rotation axis X. However, the shaft 130 is not shown as a cross-section in Figure 1. Figure 2 is a cross-sectional view of the motor 100 along the radial direction, and is a view of the AA section in Figure 1 (viewed in the direction of arrow b).

[0010] As shown in Figure 1, the motor 100 comprises a housing 110, a cover 120, and a shaft 130. The housing 110 has a substantially cylindrical housing body 111, a flange portion 112 extending radially outward (arrow c) from one end in the rotation axis direction (arrow a direction), and a bottom portion 113 that covers part or all of the other side (arrow b direction) of the housing body 111 in the rotation axis direction. The cover 120 has a substantially disc-shaped plate portion 121. The plate portion 121 of the cover 120 is connected to the flange portion 112 of the housing 110.

[0011] A hole 120h is formed in the cover 120. The hole 120h penetrates the plate portion 121 of the cover 120 in the direction of the rotation axis. A cylindrical projection 122 is provided on the cover 120 coaxially with the hole 120h, projecting to the other side (direction of arrow b) in the direction of the rotation axis. The projection 122 holds the first bearing 141, which will be described later.

[0012] The shaft 130 extends in the direction of rotation from near the bottom 113 of the housing 110 to one side of the cover 120 (in the direction of arrow a). The shaft 130 passes through the hole 120h of the cover 120 and protrudes to one side in the direction of rotation (in the direction of arrow a). The shaft 130 has one end 131 on one side in the direction of rotation (in the direction of arrow a) and the other end 134 on the other side (in the direction of arrow b). A gear may be formed on the outer circumferential surface of one end 131 of the shaft 130, as shown in the figure.

[0013] A first bearing 141 is positioned on the outer circumferential surface of the shaft 130. The first bearing 141 is a ball bearing comprising an inner ring 141i, an outer ring 141o, and rolling elements. Note that the first bearing 141 is not limited to a ball bearing, and may be any other type of bearing, such as a sleeve bearing.

[0014] The inner ring 141i of the first bearing 141 is bonded or press-fitted to the outer circumferential surface of the shaft 130. This fixes the inner ring 141i of the first bearing 141 to the shaft 130, allowing it to rotate integrally with the shaft 130 around the axis of rotation X. The outer ring 141o of the first bearing 141 is bonded or press-fitted to the inner circumferential surface of the projection 122 of the cover 120. This holds the outer ring 141o of the first bearing 141 to the projection 122 of the cover 120. With this configuration, the first bearing 141 rotatably supports the shaft 130 relative to the cover 120.

[0015] A second bearing 142 is positioned on the outer circumferential surface of the other end 134 of the shaft 130. The second bearing 142 is a ball bearing comprising an inner ring 142i, an outer ring 142o, and rolling elements. Note that the second bearing 142 is not limited to a ball bearing, and may be any other type of bearing, such as a sleeve bearing.

[0016] The inner ring 142i of the second bearing 142 is bonded or press-fitted to the outer circumferential surface of the other end 134 of the shaft 130. This fixes the inner ring 142i of the second bearing 142 to the shaft 130, allowing it to rotate integrally with the shaft 130 around the axis of rotation X. A cylindrical retaining portion 113a is provided in the center of the bottom 113 of the housing 110, protruding to one side (in the direction of arrow a) in the direction of rotation. The outer ring 142o of the second bearing 142 is bonded or press-fitted to the inner circumferential surface of the retaining portion 113a of the housing 110. This holds the outer ring 142o of the second bearing 142 in the retaining portion 113a of the housing 110. With this configuration, the second bearing 142 rotatably supports the shaft 130 relative to the housing 110.

[0017] In the direction of the rotation axis, a rotor 160 is disposed between a first bearing 141 and a second bearing 142. The inner peripheral surface of an annular portion 163a of the rotor 160, which will be described later, is fixed to the outer peripheral surface of a shaft 130. Therefore, the shaft 130 is rotatable integrally with the rotor 160.

[0018] As shown in FIG. 2, the rotor 160 has, for example, a plurality of first magnets 161, a plurality of second magnets 162, and a rotor core (magnetic body) 163. The rotor core 163 has an annular portion 163a and a plurality of magnetic pole pieces 163b that extend radially from the annular portion 163a via connecting portions 163c and 163d. Each of the plurality of first magnets 161 is disposed in a substantially rectangular space between the plurality of magnetic pole pieces 163b. The plurality of second magnets 162 are disposed between the annular portion 163a and the plurality of magnetic pole pieces 163b. However, the rotor 160 is not limited to having such a configuration.

[0019] A stator 150 is supported on the inner peripheral surface of a housing body 111. The stator 150 faces the rotor 160 in the radial direction. The stator 150 is disposed on the outer side (in the direction of arrow c) of the rotor 160 in the radial direction. The stator 150 surrounds the rotor 160 from the outer side (in the direction of arrow c) in the radial direction.

[0020] As shown in FIG. 2, the stator 150 has a stator core (magnetic body) 151 and a coil group 152. The stator core 151 is, for example, a laminate in which silicon steel sheets or the like are stacked in the direction of the rotation axis. The stator core 151 has an annular portion 154 disposed coaxially with the shaft 130 and a plurality of teeth 153 formed to extend from the annular portion 154 toward the shaft 130. In the radial direction, the plurality of teeth 153 face the rotor 160. The coil group 152 is wound around each of the plurality of teeth 153. The stator core 151 and the coil group 152 are insulated by an insulator 155 formed of an insulator.

[0021] Hereinafter, the circuit of the motor 100 will be described in detail mainly with reference to FIGS. 3 and 4. FIG. 3 is a diagram showing that in the motor unit 1, a motor drive control device 40 (hereinafter, also simply referred to as "control device 40") controls the switching elements of the circuit of the motor 100 (first circuit 10, second circuit 20, third circuit 30). FIG. 4 is a diagram showing details of each circuit in the motor 100.

[0022] The motor unit 1 includes a control device 40 and a motor 100. The control device 40 drives the motor 100 via conductors Lu, Lv, Lw. Also, as shown by arrows S1, S2, S3 in FIG. 3, the control device 40 controls the circuits (first circuit 10, second circuit 20, third circuit 30) provided in the motor 100. Specifically, the control device 40 controls the on / off of each switching element (first switching elements 13, 23, 33, second switching elements 14, 24, 34, third switching elements 15, 25, 35 described later) provided in each circuit. The control device 40 may be connected to each switching element by wire or wirelessly.

[0023] The control device 40 has, for example, a control circuit and a drive circuit not shown. The control circuit is realized, for example, by a program processing device (e.g., a microcontroller) having a configuration in which a processor such as a CPU, various storage devices such as a RAM and a ROM, and peripheral circuits such as a counter (timer), an A / D conversion circuit, a D / A conversion circuit, a clock generation circuit, and an input / output I / F circuit are connected to each other via a bus or a dedicated line. The drive circuit may have, for example, an inverter circuit that drives each coil, a pre-drive circuit that drives the inverter circuit according to a drive control signal, and a current detection circuit that detects the current flowing through each coil. The control device 40 may have a configuration in which a part or all of the control circuit and a part or all of the drive circuit are packaged as one integrated circuit device (IC), or a configuration in which the control circuit and the drive circuit are each packaged as an individual integrated circuit device. The control device 40 may be mounted, for example, on a substrate 170 (see FIG. 1) disposed inside the housing 110 of the motor 100, or may be disposed outside the motor 100.

[0024] The motor 100 includes a first circuit 10, a second circuit 20, and a third circuit 30. The first circuit 10 corresponds to the first phase (U phase in the illustrated configuration), the second circuit 20 corresponds to the second phase (V phase in the illustrated configuration), and the third circuit 30 corresponds to the third phase (W phase in the illustrated configuration). The first circuit 10, the second circuit 20, and the third circuit 30 are connected to a single contact (neutral point) P in a Y-connection (star connection).

[0025] As shown in Figure 4, the first circuit 10 is formed between two branches 10a and 10b. A single conductor Lu extending from the control device 40 splits into multiple conductors at branch 10a, and then converges back into a single conductor at branch 10b, connecting to a single contact (neutral point) P.

[0026] The first circuit 10 comprises a first coil 11, a second coil 12, a first switching element 13, a second switching element 14, and a third switching element 15 between two branches 10a and 10b. The first coil 11 and the second coil 12 are wound around multiple teeth 153 of the stator core 151, each forming part of a coil group 152. The first coil 11 and the second coil 12 may be wound around the same teeth or different teeth. The inductances of the first coil 11 and the second coil 12 may be the same, approximately the same, or different. The first switching element 13, the second switching element 14, and the third switching element 15 may each be elements capable of switching current on / off, such as switches, transistors, or FETs. In the following descriptions of the first switching element 13, the second switching element 14, and the third switching element 15, "on" indicates a state in which the current is not interrupted by the switching element, and "off" indicates a state in which the current is interrupted by the switching element.

[0027] In the first circuit 10, the first coil 11 and the second switching element 14 are connected in series. The second switching element 14 is positioned closer to the contact P than the first coil 11. Also in the first circuit 10, the second coil 12 and the third switching element 15 are connected in series. The second coil 12 is positioned closer to the contact P than the third switching element 15. The first switching element 13 is connected to the first coil 11 and the second coil 12. Specifically, the first switching element 13 is connected to the point between the first coil 11 and the second switching element 14, and to the point between the second coil 12 and the third switching element 15. When the first switching element 13 is off, the conductive path including the first coil 11 and the second switching element 14 is in parallel with the conductive path including the second coil 12 and the third switching element 15.

[0028] The first switching element 13 can switch the connection between the first coil 11 and the second coil 12 between parallel and series connections. For example, if the first switching element 13 is turned off, the second switching element 14 is turned on, and the third switching element 15 is turned on, the first coil 11 and the second coil 12 will be connected in parallel within the first circuit 10. Also, if the first switching element 13 is turned on, the second switching element 14 is turned off, and the third switching element 15 is turned off, the first coil 11 and the second coil 12 will be connected in series within the first circuit 10. Furthermore, for example, if a fault (open or short) occurs in the first coil 11, the current can be continued without passing through the first coil 11 by turning off the first switching element 13, the second switching element 14, and the third switching element 15.

[0029] As shown in Figure 4, the second circuit 20 has the same configuration as the first circuit 10. The second circuit 20 is formed between two branches 20a and 20b. A single conductor Lv extending from the control device 40 splits into multiple conductors at branch 20a, and then converges back into a single conductor at branch 20b, connecting to a single contact (neutral point) P.

[0030] The second circuit 20 comprises a first coil 21, a second coil 22, a first switching element 23, a second switching element 24, and a third switching element 25 between two branches 20a and 20b. The first coil 21 and the second coil 22 are wound around multiple teeth 153 of the stator core 151, each constituting part of a coil group 152. The first coil 21 and the second coil 22 may be wound around the same teeth or different teeth. The inductances of the first coil 21 and the second coil 22 may be the same, approximately the same, or different. The first switching element 23, the second switching element 24, and the third switching element 25 may each be elements capable of switching current on / off, such as switches, transistors, or FETs. In the following descriptions of the first switching element 23, the second switching element 24, and the third switching element 25, "on" indicates a state in which the current is not interrupted by the switching element, and "off" indicates a state in which the current is interrupted by the switching element.

[0031] In the second circuit 20, the first coil 21 and the second switching element 24 are connected in series. The second switching element 24 is positioned closer to the contact P than the first coil 21. Also in the second circuit 20, the second coil 22 and the third switching element 25 are connected in series. The second coil 22 is positioned closer to the contact P than the third switching element 25. The first switching element 23 is connected to the first coil 21 and the second coil 22. Specifically, the first switching element 23 is connected to the point between the first coil 21 and the second switching element 24, and to the point between the second coil 22 and the third switching element 25. When the first switching element 23 is off, the conductive path including the first coil 21 and the second switching element 24 is in parallel with the conductive path including the second coil 22 and the third switching element 25.

[0032] The first switching element 23 can switch the connection between the first coil 21 and the second coil 22 between parallel and series connections. For example, if the first switching element 23 is turned off, the second switching element 24 is turned on, and the third switching element 25 is turned on, the first coil 21 and the second coil 22 will be connected in parallel within the second circuit 20. Also, if the first switching element 23 is turned on, the second switching element 24 is turned off, and the third switching element 25 is turned off, the first coil 21 and the second coil 22 will be connected in series within the second circuit 20. Furthermore, for example, if a fault (open or short) occurs in the first coil 21, the current can be continued without passing through the first coil 21 by turning off the first switching element 23, the second switching element 24, and the third switching element 25.

[0033] As shown in Figure 4, the third circuit 30 has the same configuration as the first circuit 10. The third circuit 30 is formed between two branches 30a and 30b. A single conductor Lw extending from the control device 40 splits into multiple conductors at branch 30a, and then converges back into a single conductor at branch 30b, connecting to a single contact (neutral point) P.

[0034] The third circuit 30 comprises a first coil 31, a second coil 32, a first switching element 33, a second switching element 34, and a third switching element 35 between two branches 30a and 30b. The first coil 31 and the second coil 32 are wound around multiple teeth 153 of the stator core 151, each constituting part of a coil group 152. The first coil 31 and the second coil 32 may be wound around the same teeth or different teeth. The inductances of the first coil 31 and the second coil 32 may be the same, approximately the same, or different. The first switching element 33, the second switching element 34, and the third switching element 35 may each be elements capable of switching current on / off, such as switches, transistors, or FETs. In the following descriptions of the first switching element 33, the second switching element 34, and the third switching element 35, "on" indicates a state in which the current is not interrupted by the switching element, and "off" indicates a state in which the current is interrupted by the switching element.

[0035] In the third circuit 30, the first coil 31 and the second switching element 34 are connected in series. The second switching element 34 is positioned closer to the contact P than the first coil 31. Also in the third circuit 30, the second coil 32 and the third switching element 35 are connected in series. The second coil 32 is positioned closer to the contact P than the third switching element 35. The first switching element 33 is connected to the first coil 31 and the second coil 32. Specifically, the first switching element 33 is connected to the point between the first coil 31 and the second switching element 34, and to the point between the second coil 32 and the third switching element 35. When the first switching element 33 is off, the conductive path including the first coil 31 and the second switching element 34 is in parallel with the conductive path including the second coil 32 and the third switching element 35.

[0036] The first switching element 33 can switch the connection between the first coil 31 and the second coil 32 between parallel and series connections. For example, if the first switching element 33 is turned off, the second switching element 34 is turned on, and the third switching element 35 is turned on, the first coil 31 and the second coil 32 will be connected in parallel within the third circuit 30. Also, if the first switching element 33 is turned on, the second switching element 34 is turned off, and the third switching element 35 is turned off, the first coil 31 and the second coil 32 will be connected in series within the third circuit 30. Furthermore, for example, if a fault (open or short) occurs in the first coil 31, the current can be continued without passing through the first coil 31 by turning off the first switching element 33, the second switching element 34, and the third switching element 35.

[0037] In the motor 100 according to this embodiment, a single circuit (first circuit 10, second circuit 20, or third circuit 30) corresponding to a single phase can switch between series and parallel connections. Therefore, the motor 100 is highly versatile and cost-effective. Furthermore, according to this embodiment, redundancy can be provided for each phase of the motor 100 with a single circuit. Therefore, according to this embodiment, redundancy can be ensured even when a group of circuits connected in a Y-connection (star connection) is considered as one set (i.e., even when there is only one contact (neutral point) P on the motor side).

[0038] Although preferred embodiments of the motor and motor unit of the present invention have been described above, the motor and motor unit of the present invention are not limited to the configurations of the above embodiments. The motor may have only one of the first circuit, second circuit, and third circuit, or only two of them. The motor may also have four or more circuits similar to the first circuit. Some or all of the first circuit, second circuit, and third circuit may have other coils besides the coils described above.

[0039] Furthermore, the motor of the present invention may have multiple circuits corresponding to multiple phases connected in a delta connection. For example, the motor and motor unit of the present invention may be the motor 200 and motor unit 2 shown in Figure 5. In motor unit 2 and motor 200, the same reference numerals are used for components similar to those in motor unit 1 and motor 100.

[0040] In motor 200, the first circuit 10, the second circuit 20, and the third circuit 30 are connected in a delta configuration at three contacts Pu, Pv, and Pw. Similar to motor 100, motor 200 allows switching between series and parallel connections within a single circuit (first circuit 10, second circuit 20, or third circuit 30) corresponding to a single phase. Therefore, motor 200 is highly versatile and cost-effective. Furthermore, this modified configuration also allows for redundancy in each phase of motor 200 using a single circuit.

[0041] Although the motors 100 and 200 in the above embodiments and modifications are drive devices, the motors 100 and 200 may also be used as power generators, either as they are or with some modifications. For example, by rotating the shaft 130 of the motors 100 and 200 with an external force, kinetic energy can be converted into electrical energy. In this case, the power generator of the present invention can switch between series and parallel connections in one circuit (first circuit 10, second circuit 20, or third circuit 30) corresponding to one phase. Therefore, the power generator of the present invention is highly versatile and cost-effective. In this case, redundancy can be provided for each phase of the power generator with one circuit each.

[0042] Furthermore, those skilled in the art can modify the motor and motor unit of the present invention as appropriate, and change the shape, dimensions, and combinations of various components, in accordance with conventionally known knowledge. As long as such modifications still possess the configuration of the present invention, they are of course included within the scope of the present invention. [Explanation of symbols]

[0043] 1,2...Motor unit, 10,20,30...Circuit, 11,21,31...First coil, 12,22,32...Second coil, 13,23,33...First switching element, 14,24,34...Second switching element, 15,25,35...Third switching element, 40...Control device, 100,200...Motor.

Claims

1. The circuit comprises a first coil, a second coil, and a first switching element connected to the first coil and the second coil, The circuit corresponds to the first phase, The first switching element is capable of switching the connection between the first coil and the second coil between a parallel connection and a series connection in a motor.

2. The circuit further comprises one of the aforementioned circuits, One of the circuits is the motor according to claim 1, which corresponds to the second phase.

3. The circuit further comprises one of the aforementioned circuits, One of the circuits is the motor according to claim 2, which corresponds to the third phase.

4. The motor according to any one of claims 1 to 3, wherein the circuit further comprises a second switching element and a third switching element.

5. The second switching element is connected in series with the first coil, The third switching element is connected in series with the second coil, The motor according to claim 4, wherein the first switching element is connected to a point between the first coil and the second switching element, and to a point between the second coil and the third switching element.

6. A control device and a motor according to any one of claims 1 to 3, The control device is a motor unit that drives the motor and controls the circuit.

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