Coreless rotating electric machine and electric vehicle

Abstract

A coreless rotating electric machine capable of improving responsiveness when switching characteristics while maintaining a predetermined torque even at high speed rotation is provided. [Solution] A coreless rotating electric machine having a housing 12, a rotating shaft 14 supported by the housing 12 for free rotation, a cylindrical operating coil 18 having one end face supported by a stator, and a cylindrical rotor 16 having one end face supported by the rotating shaft 14 and equipped with a permanent magnet 16a on the surface facing the operating coil 18, wherein the operating coil 18 consists of three phases, each phase being composed of multiple coils, and the machine is equipped with a circuit section that enables the connection type of the coils constituting each phase to be switched between a series type and a parallel type.

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine, and more particularly to a rotating electric machine suitable for performing efficient operation, and an electric vehicle using the same. [Background technology]

[0002] As a technique for changing the characteristics of a motor as a rotating electric machine, switching the connection of the internal windings has been proposed, as disclosed in Patent Document 1 and Patent Document 2. For example, Patent Document 1 is a technique related to a motor for a machine tool, in which a coil consisting of three phases is used as a stator, and the coils constituting each phase are composed of multiple coils with different numbers of turns. Then, one to multiple coils are selectively connected in series so that the number of turns of the entire coil is reduced during high speed rotation, and the number of turns of the entire coil is increased during low speed rotation.

[0003] Furthermore, Patent Document 2 discloses a technology related to a motor for a starter generator, mainly for an electric tool or an automobile. The motor disclosed in Patent Document 2 also uses a coil consisting of three phases as a stator, similar to the motor disclosed in Patent Document 1. Each phase is composed of multiple coils, and the multiple coils constituting each phase are provided with a switch device that can switch the connection between series and parallel. With this configuration, in the series connection, the magnetic field excited by the coils becomes stronger, improving the torque, and in the parallel connection, the magnetic field becomes weaker, realizing high-speed rotation.

[0004] Patent documents 3 and 4 also state that in a coreless motor having multiple phases, the characteristics of the motor can be changed by determining whether the connection method of each phase is series or parallel. Furthermore, Patent document 5 states that in a motor having fixed coils, a circuit is used to switch the connection method of the three-phase coils between series and parallel. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3596711 [Patent Document 2] Special Publication No. 2010-537621 [Patent Document 3] JP 2014-121102 A [Patent Document 4] JP 2019-54628 A [Patent Document 5] JP 2011-229221 A Summary of the Invention [Problem to be solved by the invention]

[0006] According to the techniques disclosed in Patent Documents 1 and 2, it is believed that it is indeed possible to change the characteristics of a motor and realize the functions of multiple motors with a single motor.

[0007] However, in the technology disclosed in Patent Document 1, the number of turns of the coil is essentially changed, which may result in a drastic decrease in torque at high rotation speeds.In addition, in the technology disclosed in Patent Document 2, the self-inductance is large due to the influence of the iron core, and there is a concern that a time lag may occur between switching and the change in characteristics.

[0008] In addition, the coreless motors disclosed in Patent Documents 3 and 4 have a small capacity. For this reason, the concept of switching the motor characteristics during use could not be conceived. Furthermore, if the capacity of a coreless motor is increased, there is a risk that the operating coil will be deformed due to the counter torque received when rotating the rotor, and it has been considered common knowledge among those skilled in the art that it is not suitable for large capacity. Therefore, it was common technical knowledge that the technology of the cored motor disclosed in Patent Document 5 could not be applied as it is.

[0009] Therefore, the present invention aims to solve the above problems and break through the conventional technical common sense by providing a coreless rotating electric machine that can increase the capacity of the coreless rotating electric machine, maintain a specified torque even at high revolutions, and improve responsiveness when switching characteristics, and an electric vehicle using the same. [Means for solving the problem]

[0010] The coreless rotating electric machine according to the invention for achieving the above-mentioned object is a coreless rotating electric machine having a housing, a cylindrical, non-rotating operating coil, and a rotor having a magnet located on the opposing surface of the operating coil and spaced apart from the operating coil, wherein the operating coil is made up of a plurality of phases, each phase being made up of a plurality of coils, and the machine is characterized in that it is provided with a circuit section that enables the connection type of the coils constituting each phase to be switched between a series type and a parallel type.

[0011] In addition, in the coreless rotating electric machine having the above-mentioned features, the switching to the parallel type is characterized in that it is possible to switch in multiple stages by changing the number of coils in a pair according to the number of coils constituting each phase. With such a feature, it is possible to change the number of coils connected in parallel to suit the desired characteristics of the coreless rotating electric machine.

[0012] In addition, in a coreless rotating electric machine having the above-mentioned characteristics, the circuit units may be provided between the coils constituting the poles, and the circuit units may be switched in units of the poles corresponding to each phase. With such characteristics, the number of switchable systems (characteristics) can be increased according to the number of coils and the number of circuit units.

[0013] Furthermore, in a coreless rotating electric machine having the above-mentioned features, the circuit section can be configured with one or more semiconductor elements. Such a configuration makes it possible to reduce the size and weight of the coreless rotating electric machine itself, and also simplifies the internal wiring, etc.

[0014] Furthermore, in a coreless rotating electric machine having the above-mentioned characteristics, it is preferable to provide a control unit that switches the circuit unit so that the number of coils connected in series is increased on the low rotation speed side relative to a predetermined threshold rotation speed, and the number of coils connected in parallel is increased on the high rotation speed side. By having such characteristics, it is possible to balance power consumption and generated torque, and to widen the usable rotation range.

[0015] In addition, in the coreless rotating electric machine having the above-mentioned characteristics, the actuating coil may be cylindrical and have a deformation-resistant layer. This configuration allows a gap to be provided in the internal space of the motor, making it possible to effectively utilize the internal space of the motor. Furthermore, by having the deformation resistance, it is possible to prevent deformation of the actuating coil due to the counter torque when the rotor rotates, even if the motor capacity is increased.

[0016] In addition, in the coreless rotating electric machine having the above-mentioned characteristics, it is preferable that the operating coil has three phases, U, V, and W. By having such characteristics, it is possible to avoid an increase in the number of coils and circuits, and to reduce manufacturing costs during mass production.

[0017] In addition, in the coreless rotating electric machine having the above-mentioned characteristics, it is preferable that the coil is made of Litz wire. With such a characteristic, it is possible to obtain strength for maintaining the shape of the actuating coil, and since it is not necessary to use iron or copper plates for the actuating coil, it is possible to reduce self-inductance.

[0018] Furthermore, an electric vehicle for achieving the above object is characterized in that a coreless rotating electric machine having the above characteristics is applied to a propulsion power source. Effect of the Invention

[0019] A coreless rotating electric machine having the characteristics described above can accommodate larger capacities than were previously possible, and can maintain a specified torque even at high revolutions while improving responsiveness when switching characteristics. [Brief description of the drawings]

[0020] [Figure 1] FIG. 2 is a diagram showing a circuit configuration of an operating coil in a motor according to the first embodiment, illustrating an example in which coils constituting each phase are connected in series. [Diagram 2] FIG. 2 is a diagram showing a circuit configuration of an operating coil in a motor according to the first embodiment, illustrating an example in which coils constituting each phase are connected in parallel. [Diagram 3] 1 is a side cross-sectional view showing a schematic configuration of a motor according to the present invention. [Figure 4] FIG. 4 is a diagram showing a cross-sectional configuration of an actuation coil. [Diagram 5] FIG. 2 is a diagram showing a cross-sectional configuration of a Litz wire constituting an operating coil according to an embodiment. [Figure 6] 11 is a graph showing the relationship characteristics between torque and rotation speed, and between torque and current when the connection method of the coils that make up the operating coil is switched. [Figure 7] 10 is a graph showing changes in characteristics when a motor is operated by switching the connection method of the coils that make up the actuation coil. [Figure 8] 13 is a graph showing the change in output characteristics when the motor is operated by switching the connection method of the coils that make up the actuation coil, and the zone for switching according to the situation. [Figure 9] FIG. 13 is a diagram showing a circuit configuration of an operating coil in a motor according to a second embodiment, showing an example in which all four coils constituting each phase are directly connected. [Figure 10] FIG. 13 is a diagram showing the circuit configuration of the differential coils in a motor according to a second embodiment, illustrating an example in which two of the four coils constituting each phase are connected in series, and the coils that make up a set of series connections are connected in parallel. [Figure 11]FIG. 13 is a diagram showing a circuit configuration of an operating coil in a motor according to a second embodiment, showing an example in which all four coils constituting each phase are connected in parallel. [Figure 12] 10 is a graph showing changes in characteristics when the motor according to the second embodiment is operated by switching the connection method of the coils that make up the operating coil. [Figure 13] FIG. 11 is a diagram showing a specific example of operation switching when a three-stage switching motor is applied to a vehicle (relationship between change in rotation speed and connection switching). [Figure 14] FIG. 11 is a diagram showing a specific example of operation switching when a three-stage switching motor is applied to a vehicle (relationship between speed change and connection switching). [Figure 15] FIG. 11 is a diagram showing a specific example of operation switching when a three-stage switching motor is applied to a vehicle (relationship between changes in road surface inclination conditions and connection switching). [Figure 16] FIG. 13 is a diagram showing an application form in which one phase has 12 coils and five circuit units. [Figure 17] FIG. 11 is a cross-sectional view showing an example of a coil arrangement when twelve coils are used. [Figure 18] FIG. 1 is a diagram showing an example of a circuit for a six-stage switching motor, with a partially enlarged view of the portion surrounded by dashed line A in the figure. [Figure 19] 20 is a table showing switching of the circuit units in FIG. 18 and changes in the connection state. [Figure 20] FIG. 13 is a diagram showing an example of a circuit in which an actuating coil is configured with two phases. [Figure 21] FIG. 2 is a schematic diagram showing an example in which coils of each phase are connected in series in a two-phase operating coil. [Figure 22] FIG. 2 is a schematic diagram showing an example in which coils of each phase are connected in parallel in a two-phase operating coil. [Figure 23] FIG. 13 is a diagram showing an example of a circuit in which the actuating coil is configured with five phases. [Figure 24] FIG. 2 is a schematic diagram showing an example in which coils of each phase are connected in series in a five-phase operating coil. [Diagram 25]FIG. 2 is a schematic diagram showing an example in which coils of each phase are connected in parallel in a five-phase operating coil. [Figure 26] 11 is a diagram showing the relationship between a clock and Lo and Hi in various command signals when a circuit section is configured using switching elements. FIG. [Figure 27] FIG. 13 is a diagram illustrating a configuration example of a control unit that outputs a command signal to a circuit unit using a switching element. [Figure 28] FIG. 2 is a diagram showing an example of a circuit of blocks constituting each phase. [Figure 29] FIG. 13 is a diagram showing an example of a circuit configuration in which the number of coils constituting the phases that make up the operating coil is an odd number (three), and the coils are connected in series. [Diagram 30] FIG. 13 is a diagram showing an example of a circuit configuration in which the number of coils constituting the phases that make up the operating coil is an odd number (three), and the coils are connected in parallel. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, a motor will be described as an example of the coreless rotating electric machine.

[0022] [Basic configuration] First, the basic configuration of a motor 10 according to this embodiment will be described with reference to Figures 3 to 5. The motor 10 according to this embodiment is a so-called coreless motor that is basically composed of a housing 12, a rotating shaft 14, an operating coil 18, and a rotor 16. The housing 12 is an element that constitutes the outer shell, and houses the rotating shaft 14, the operating coil 18, and the rotor 16 in its internal space. The rotating shaft 14 is disposed so as to pass through the housing 12, and is rotatably supported by a bearing 12a provided at the intersection with the housing 12.

[0023] The operating coil 18 is configured to have a cylindrical shape by a coil group divided into a plurality of phases (three phases, U phase, V phase, and W phase, in this embodiment) (see FIG. 4). The U phase, V phase, and W phase constituting the operating coil 18 are each composed of a plurality of coils constituting a pole. In the embodiment shown in FIG. 4, each phase is divided into 1 / 2 (i.e., two equal parts) and is configured to have a first coil U1, a second coil U2, a first coil V1, a second coil V2, a first coil W1, and a second coil W2. As a more specific example, the phase constituting the inner cylindrical coil body is the U phase, the phase located outside the inner cylindrical coil body in the radial direction is the V phase, and the phase located further outside the V phase is the W phase, and the first coils (U1, V1, W1) and the second coils (U2, V2, W2) are defined for each phase. Note that the U phase, V phase, and W phase from the inside are just an example, and a different order and overlapping manner may be used. In addition, in Fig. 4, each phase is disposed so as to be shifted in the circumferential direction by approximately 1 / 3 of an electrical angle. One end face of the operating coil 18 configured in this manner is configured to be supported by the stator (housing 12 in the example shown in Fig. 3), which is a fixed member.

[0024] Here, to simplify the explanation, it has been said that the phases are "shifted in the circumferential direction by approximately 1 / 3 each", but strictly speaking, the U, V, and W phases are shifted by 120° in electrical angle. In terms of mechanical angle (actual angle), in the case of two poles, the V phase is shifted by 120° and the W phase is shifted by 240° relative to the U phase. In the case of four poles, the V phase is shifted by 60° or 240° relative to the U phase, and the W phase is shifted by 120° or 300°. In the case of six poles, the V phase is shifted by 40°, 160°, or 280° relative to the U phase, and the W phase is shifted by 80°, 200°, or 320° relative to the U phase, and in the case of eight poles, the V phase is shifted by 30°, 120°, 210°, or 300° relative to the U phase, and the W phase is shifted by 60°, 150°, 240°, or 330° relative to the U phase. In this way, the shifts follow the rules for 10 poles and 12 poles. The U phase, V phase, and W phase are each shifted by 120° in electrical angle, but when expressed in mechanical angle the angle of shift changes depending on the number of poles, so Figure 4 shows a schematic representation.

[0025] The rotor 16 has a cylindrical outer yoke 16c and inner yoke 16b, and a permanent magnet 16a, and one end face is connected to the rotating shaft 14. The outer yoke 16c is an element located on the outer periphery side of the operating coil 18 described above (the outer periphery side in the radial direction based on the center of the cylinder), and the inner yoke 16b is an element located on the inner periphery side of the operating coil 18. In the motor 10 according to this embodiment, the permanent magnet 16a is configured to be provided inside the outer yoke 16c, on the surface facing the operating coil 18.

[0026] A coreless motor with this configuration can obtain a large output and torque compared to the size of the motor because the power source is separated from the rotating shaft 14. Also, because the operating coil 18 does not have an iron core, the self-inductance can be kept small.

[0027] Furthermore, in the motor 10 configured as above, when constructing the operating coil 18, a Litz wire as shown in Fig. 5 is used for the winding and is shaped by coating with an insulating layer. The Litz wire is a so-called twisted wire formed by bundling a plurality of conductive wires 18a, and the outer periphery of each conductive wire 18a is covered with an enamel layer 18b. Furthermore, the outer periphery of the conductive wires 18a (bundle of conductive wires 18a) that make up the twisted wire is provided with an outer skin layer 18c made of a fibrous material such as glass fiber.

[0028] Even with this configuration, it is possible to suppress the generation of eddy currents (eddy current loss) that occurs when iron or copper plates are used to maintain the shape, and to contribute to reducing self-inductance.

[0029] [First embodiment] In the motor 10 having such a basic configuration, as shown in FIG. 1 and FIG. 2, each phase constituting the operating coil 18 is composed of two coils (first coil U1, second coil U2, first coil V1, second coil V2, first coil W1, second coil W2). The input / output coil 18 according to this embodiment is composed of a three-phase coil. This is an example, and the shape of the coil does not determine the number of poles. For example, in the case of 12 poles, each of the phases U1, U2, V1, V2, W1, and W2 may all be a coil body with six coils in series, and in the case of 8 poles, each of the phases U1, U2, V1, V2, W1, and W2 may all be a coil body with four coils in series. In this way, the number of poles cannot be determined from the shape of the input / output coil 18, and any number of poles is acceptable as long as the number of poles is an even number. Between the coils constituting each phase (first coil U1 and second coil U2, first coil V1 and second coil V2, first coil W1 and second coil W2), a circuit unit 20 (20U, 20V, 20W) constituting a change-over switch is provided.

[0030] The circuit section 20 is composed of two changeover switches (a first switch A and a second switch B) arranged in parallel, each having one input port and two output ports. The first coils U1, V1, and W1 are respectively connected to the input ports of the first switch A, and a first bypass line is connected to the input port of the second switch B. The output ports of the first switch A are connected to second coils U2, V2, and W2 on the a-port side, and a second bypass line is connected to the b-port side. In addition, the output port of the second switch B is open (unconnected) on the a-port side, and branch lines from the second coils U2, V2, and W2 are connected to the b-port side.

[0031] With such a circuit configuration, it is possible to switch between a series connection and a parallel connection of the first coils U1, V1, W1 and the second coils U2, V2, W2 by switching the switches constituting the circuit unit 20. Specifically, when the first switch A and the second switch B are both connected to the a port, the first coils U1, V1, W1 and the second coils U2, V2, W2 are connected in series (see FIG. 1). On the other hand, when the first switch A and the second switch B are both connected to the b port, the first coils U1, V1, W1 and the second coils U2, V2, W2 are connected in parallel (see FIG. 2). That is, the first switch A and the second switch B are configured to have the same switching timing.

[0032] In such a switching control, a system (referred to as a first system) in which the first coils U1, V1, W1 and the second coils U2, V2, W2 are connected in series has good torque characteristics. On the other hand, a system (referred to as a second system) in which the first coils U1, V1, W1 and the second coils U2, V2, W2 are connected in parallel has good rotation characteristics. Explained using the torque constant of the motor, by connecting in series, the torque constant of the motor becomes large, and the torque per current becomes large (good torque characteristics). On the other hand, by connecting in parallel, the torque constant of the motor becomes small, and it becomes possible to rotate at high speed (good rotation characteristics). In this embodiment, the purpose of terminal switching is to change the torque constant, and as a result, the rotation characteristics and torque characteristics change, and it is possible to provide an optimal motor for each situation.

[0033] Figure 6 shows the relationship between torque and rotation speed (TN characteristics) and the relationship between torque and current (TI characteristics) for the first and second systems. Comparing the second system with the first system, it can be seen that the second system has a higher normal rotation range, and therefore the rise in power consumption as torque increases is steeper. On the other hand, it can be seen that the first system can generate high torque in the low rotation range, but its maximum rotation speed remains at about half that of the second system.

[0034] Considering the characteristics of each system, it is believed that by using the first system in the low rotation range and the second system in the high rotation range, it is possible to effectively utilize the advantages of each of the two motors. Figure 7 shows the motor characteristics (TN characteristics and TI characteristics) obtained when switching between the first and second systems in a rotation range where the torque is half that of the maximum torque. The motor 10 according to this embodiment, which switches between systems, can generate high torque while suppressing power consumption (current) in the low rotation range. Furthermore, in areas where operation at low torque is not a problem, it is possible to achieve a high rotation speed that cannot be achieved with the first system.

[0035] To realize such a configuration, the switches (first switch A, second switch B) constituting the circuit unit 20 need to be switched simultaneously for the three phases U, V, and W. For this reason, the motor 10 according to the embodiment is provided with a control unit 22 that outputs a switching signal to the circuit unit 20. Note that the control unit 22 is preferably configured to use a predetermined threshold value for the number of rotations as a reference, and to increase the number of coils connected in series in each phase on the lower rotation side than the threshold, and to increase the number of coils connected in parallel on the higher rotation side. This is because it is possible to balance the power consumption and the generated torque, and to widen the usable rotation range.

[0036] When a motor 10 having such a configuration is applied to the power of a vehicle to configure an electric vehicle, the output characteristics of the first system (series) and the second system (parallel) will show the tendency as shown in Fig. 8. For this reason, from the viewpoint of generated torque, required rotation range, and power consumption, it is possible to operate the vehicle by switching between the systems divided into three zones.

[0037] That is, the first zone should be applied when output torque is required (approximately more than half of the maximum torque), such as when starting or climbing a hill (first system: at low revolutions). The second zone should be applied when the revolution speed is relatively low, output torque is not required (approximately less than half of the maximum torque), and power consumption needs to be reduced (for example, during normal driving) (first system: at high revolutions). Furthermore, the third zone should be applied when high revolutions are required and output torque is not required, such as when driving at high speed (approximately less than half of the maximum torque) (second system: at high revolutions).

[0038] [effect] With motor 10 having the above-described characteristics, as power consumption improves, it is possible to obtain a predetermined torque even at high rotation speeds (meaning that a high torque can be obtained even at a high rotation speed compared to the high rotation speed range of a system (first system) in which the first coils U1, V1, W1 and the second coils U2, V2, W2 are connected in series).

[0039] Furthermore, by not providing an iron core in the coil and ensuring the strength to maintain the shape with the Litz wire, it is possible to keep the self-inductance small, and it is possible to improve the responsiveness from switching by the connection changeover in the circuit section 20 to switching of the characteristics, and to prevent deformation of the operating coil 18 due to the counter torque when rotating the rotor 16. Note that, in order to make the operating coil 18 resistant to deformation, a deformation-resistant coil body can be constructed by taking various methods, such as providing a deformation-resistant layer (not shown) or providing individual reinforcing means.

[0040] The deformation-resistant layer added to the operating coil 18 may be a film sheet attached to at least one side (inner or outer) of the cylindrically configured operating coil 18. The film sheet may be made of fiber reinforced plastic (FRP) or the like, and is preferably made of carbon fiber reinforced plastic (CFRP) or the like. With this configuration, it is possible to prevent the operating coil 18 from being deformed by the counter torque of the rotor 16, even if the motor 10 is made large capacity.

[0041] Furthermore, when the operating coil 18 is provided with a reinforcing means, a circular reinforcing ring (not shown) made of metal or the like may be disposed at the free end of the cylindrically formed operating coil 18.

[0042] Coreless motors have no iron core, which means that their inductance is small. If the inductance is large, it becomes difficult for current changes to occur. For this reason, forcing a change in current will generate high voltage. If a large current is flowing and the current is suddenly cut off (for example, switching from parallel to series cuts the current in that instant), high voltage will be generated. When this happens, there is a high possibility that an overvoltage will be applied to the circuit, damaging the circuit elements. This is because circuit elements are vulnerable to overvoltage.

[0043] For this reason, in the case of motors with large inductance such as cored motors, countermeasures must be devised, such as adding additional equipment to prevent the generation of high voltages when the circuits are switched, or adding work procedures such as cutting the current temporarily and then switching it over. Therefore, when using winding switching for cored motors, multiple elements must be used as various preventive measures to avoid accidents caused by overvoltages due to sudden current changes when switching the windings, which makes the wiring complicated.

[0044] In contrast, in the motor 10 (coreless motor) configured according to this embodiment, the overvoltage generated is only a fraction (e.g., 1 / 20 or less) of that generated in a cored motor (iron core motor). This eliminates the need for extra auxiliary equipment or accident prevention work, and allows instantaneous switching between series and parallel. This is a technology that was first conceived and successfully demonstrated by the inventors of the present application.

[0045] Generally, when a motor is applied to a vehicle, in the case of a motor with high inductance such as a cored motor, if the supply current to the motor is cut while under load, resistance acts to stop the rotation of the rotor, causing the speed to drop and shock to occur. In contrast, when the motor 10 according to the present invention is used, it can be said that shock caused by inductance is unlikely to occur.

[0046] [Second embodiment] Next, the configuration of a motor 10 according to a second embodiment will be described with reference to Fig. 9 to Fig. 11. The motor 10 according to this embodiment has a different configuration of the actuating coil 18 from the motor 10 according to the first embodiment. Note that Fig. 3 will be used to explain the configuration of the motor 10 where the functions are similar.

[0047] The operating coil 18 according to this embodiment is a three-phase, twelve-pole coil, with four coils per phase (a total of twelve coils). In the operating coil 18 configured in this manner, circuit sections 20 (20U1, 20U2, 20U3, 20V1, 20V2, 20V3, 20W1, 20W2, 20W3) are provided between the coils that constitute each phase (first coil U1, second coil U---2, third coil U3, fourth coil U4, first coil V1, second coil V2, third coil V3, fourth coil V4, first coil W1, second coil W2, third coil W3, fourth coil W4).

[0048] As for the configuration of the circuit unit 20, the circuit units 20U1, 20U3, 20V1, 20V3, 20W1, and 20W3 are similar to the circuit units 20U, 20V, and 20W according to the first embodiment. On the other hand, the circuit units 20U2, 20V2, and 20W2 are configured such that the number of input ports and the number of output ports of the second switch B are reversed to those of the first switch A.

[0049] In motor 10 configured as described above, by setting the first switch A and the second switch B to port a for each of circuit sections 20U1 to 20W3 in the U, V, and W phases, the first coil U1 to the fourth coil U4, the first coil V1 to the fourth coil V4, and the first coil W1 to the fourth coil W4 are each connected in series (this state is called 1 parallel: see Figure 9).

[0050] Also, when the first switch A and the second switch B of the circuit units 20U2, 20V2, and 20W2 are set to the b port from the 1-parallel state, for example, in the U phase, the first coil U1 and the second coil U2 are connected in series, and the third coil U3 and the fourth coil U4 are connected in series, and the pair of the first coil U1 and the second coil U2 and the pair of the third coil U3 and the fourth coil U4 are connected in parallel. Note that the coils are connected in the same way in the V phase and the W phase (this state is called 2-parallel: see FIG. 10).

[0051] Furthermore, in each of the U phase, V phase, and W phase, when the first switch A and the second switch B of the circuit sections 20U1 to 20W3 are set to port b, the first coil U1 to the fourth coil U4, the first coil V1 to the fourth coil V4, and the first coil W1 to the fourth coil W4 are each connected in parallel (this state is called 4-parallel: see Figure 11).

[0052] In the motor 10 configured as above, the more coils connected in series, the higher the torque characteristics (single-parallel) and the more coils connected in parallel, the higher the rotation characteristics (four-parallel). Taking advantage of these characteristics, the relationship between torque and rotation speed (TN characteristics) and the relationship between torque and current (TI) when operating the motor 10 by switching between the one-parallel and four-parallel systems are shown in Figure 12.

[0053] According to Fig. 12, by switching the system from 1-parallel to 2-parallel to 4-parallel as the rotation speed increases, it is possible to suppress power consumption to a predetermined value or less and realize high torque operation. In addition, by switching between 2-parallel and 4-parallel operation, it is possible to realize operation in a high rotation range that cannot be achieved with 1-parallel. For example, if the motor 10 having such a configuration is applied to the propulsion power of an electric vehicle, the 4-parallel, 2-parallel, and 1-parallel will function as a speed change mechanism equivalent to a top gear, a second gear, and a low gear, respectively.

[0054] [effect] Even with the motor 10 having this configuration, a predetermined torque can be obtained even in the high rotation range, similar to the motor 10 according to the first embodiment. Furthermore, by not having an iron core in the coil and ensuring the strength to maintain the shape by using Litz wire, the self-inductance can be kept small, and the responsiveness from switching by connection changeover in the circuit section 20 to changing of characteristics can be improved. Furthermore, by increasing the number of coils and circuit parts, the degree of freedom in switching characteristics can be improved.

[0055] [Operation Switching] A specific example of operation switching when the motor 10 according to this embodiment is applied to an electric vehicle will be described with reference to Figures 13 to 15. This embodiment corresponds to an example of operation switching in electric vehicles in general, such as wheelchairs, motorcycles, electric bicycles, so-called senior cars, automobiles, and AGVs (automated transport vehicles), and can also be seen as common to changes in rotation speed and load in electric lawnmowers equipped with rotary blades, etc.

[0056] As can be seen from Fig. 13, at the start (= when the vehicle starts moving), the rotation is low and an initial torque is required to move the vehicle, so the coil connection is set to L (low), i.e., in series (1 parallel). After starting, for example, when the rotation speed of motor 10 reaches 700 rpm (equivalent to 30 km / h), the connection is switched from L to 2 parallel. Note that in this example, the connection is set to be switched depending on the rotation speed of motor 10. Therefore, if the vehicle speed is further increased and the rotation speed of motor 10 reaches, for example, 1400 rpm (equivalent to 60 km / h), the connection is switched to 4 parallel.

[0057] If the vehicle speed is further increased and the vehicle continues traveling at 100 km / h (for example, the rotation speed of the motor 10 is 2000 rpm) in 4-parallel, when the vehicle enters a slight uphill slope (incline angle α), the load on the motor 10 increases, causing the rotation speed to decrease and the speed to drop. For example, when the rotation speed drops to about 1167 rpm (equivalent to 50 km / h: 5 / 6 of 1400 rpm), the vehicle will switch to 2-parallel.

[0058] Furthermore, when the road changes from a slight uphill slope to a steep slope (inclination angle β), the load on the motor 10 increases further, the rotation speed decreases, and the speed drops. For example, when the rotation speed drops to about 467 rpm (equivalent to 20 km / h: 2 / 3 of 700 rpm), it switches to series (1 parallel: L). Note that settings such as 50 km / h (1167 rpm) and 20 km / h (467 rpm) when traveling up a slope correspond to the hysteresis fluctuation width.

[0059] When the vehicle accelerates gradually while traveling uphill, and reaches a speed of about 30km / h (700rpm) on a flat road, the connection type of the motor 10 switches to 2-parallel. When the vehicle accelerates further on a flat road and reaches a speed of 60km / h (1400rpm), the connection type of the motor 10 switches to 4-parallel, and the vehicle can accelerate up to about 100km / h (2000rpm). Up to this point, the electronic gear is controlled to switch as the motor rotation speed increases.

[0060] In contrast, when the vehicle enters a downhill slope (e.g., a steep slope with an inclination angle γ), the electronic gears are switched in response to a command signal from the rider, and braking is performed using the rotational resistance of the motor 10 (=regenerative braking: so-called engine braking). For example, on a steep slope, the speed is gradually reduced in 4-parallel mode, down to about 60 km / h (1400 rpm). After that, when the downhill slope becomes gentle (e.g., with an inclination angle θ), the speed is switched to 2-parallel and reduced further. By gradually reducing the speed (rotation speed) in this manner, it is possible to prevent a sudden load from being placed on the motor 10.

[0061] When the vehicle speed drops to about 30 km / h (700 rpm) on a gentle downhill slope, the connection type of the motor 10 is switched to 1 parallel (series) and the vehicle reaches a flat road. When going downhill, the power source can be charged by applying regenerative braking as described above.

[0062] The above flow is shown in FIG. 14 and FIG. 15 as switching between high speed (Top: T), medium speed (Second: S), and low speed (Low: L), and will be described below.

[0063] First, the vehicle starts on flat ground and runs in L when the speed is in the range of 0-20 km / h, switches to S when the speed reaches 20 km / h, switches to T at 60 km / h, and reaches 100 km / h at T. In section A shown in FIG. 14, the accelerator is fully open, and the rotation speed of motor 10 is detected and the electronic gear is automatically switched. In this section, the rotation speed of motor 10 increases as the vehicle accelerates, but the accelerator signal (manual accelerator signal) input by the driver is a signal to increase the rotation speed to the maximum. For this reason, the manual accelerator signal becomes greater than the rotation speed of motor 10.

[0064] Next, when the vehicle enters an uphill slope, the speed drops to about 60 km / h and the electronic gear switches to S, and the S state is maintained even when the vehicle enters a steeper slope after that. In this section (section B' in FIG. 14), the electronic gear is not controlled by the motor's rotation speed (speed), but is controlled by the accelerator opening (current control). When the vehicle reaches the top of the slope and enters flat ground (exiting section B'), the electronic gear switches to rotation speed control (speed control), and the electronic gear switches to L to accelerate the vehicle, and then switches to S as the speed (rotation speed) increases, and then switches to T. Here, the top speed at T reaches about 100 km / h. In section B shown in FIG. 14, electronic gear switching control based on the accelerator opening takes precedence. Therefore, when the motor 10 rotation speed (speed) is lower than the support based on the accelerator opening, the electronic gear is switched by a current command based on the accelerator opening. That is, in section B', the rotation speed of the motor 10 drops as the vehicle speed decreases, but the electronic gear function is automatically switched depending on the current value to maintain the vehicle speed at 60 km / h. As described above, in section B, the rotation speed (speed) of the motor 10 relative to the accelerator opening remains low. Therefore, in section B, the manual accelerator signal is also greater than the rotation speed of the motor 10.

[0065] Next, when the vehicle starts going downhill from a flat road, it starts going down in T even if the downhill slope is steep, and when the slope becomes gentler, it switches to S, and then when the vehicle reaches flat ground, it switches to L. In this section C, the rotation speed (speed) of the motor 10 becomes larger than the accelerator opening (current command) due to gravity acceleration. Therefore, the electronic gear is switched according to the driver's adjustment of the accelerator opening (accelerator command).

[0066] Next, another mode of the driving switching pattern is shown in Fig. 15. In the example shown in Fig. 15, the top gear is selected in the range from flat ground to a small inclination angle of an uphill slope. After that, when the inclination angle of the uphill slope becomes medium, the gear is switched to second gear, and when the inclination angle becomes large, the gear is switched to low gear. Then, when the inclination angle becomes gentle at the top of the slope, the gear is switched to second gear again, and when the vehicle reaches a plateau and flat ground, the gear is switched to top gear.

[0067] Generally, there is a trade-off between increasing the torque of a motor and increasing the maximum rotation speed of the motor. When trying to increase the torque of a motor, the maximum rotation speed decreases, and when trying to increase the maximum rotation speed of a motor, the maximum torque decreases. In the past, high rotation speed was achieved by increasing the voltage of the power supply and high torque was achieved by increasing the current of the power supply, but this control method has safety issues and technical limitations. The inventors of the present invention solved this problem by considering automatic electrical switching between motors with different characteristics. By taking such measures, it is possible to obtain the same effect as automatically switching between multiple motors with different characteristics by enabling multiple-stage circuit switching (electronic gear switching) such as low gear, 2nd gear, and top gear while keeping the motor itself as one.

[0068] Here, low gear has high torque and low rotation speed, and high torque can be generated with a small current. In order to increase the rotation speed in low gear, a high voltage is required, but since the low gear stage operates at low rotation speed, high voltage is not required. Also, 2nd gear has medium torque and medium rotation speed, and top gear has low torque and high rotation speed (high speed rotation is possible with low voltage). In order to obtain high torque in top gear, a large current is required, but since the top gear stage operates at low torque, high current is not required.

[0069] In this way, by providing the motor with an electronic gear switching function, one motor can handle both high torque and high speed rotation. This means that there is no need to increase the driver's voltage output or current output. This reduces the overload on the motor and suppresses sudden increases in motor temperature.

[0070] As described above, the motor 10 according to the present invention can switch between three or more stages of characteristics by switching between a series Lo state and multiple parallel states (e.g., second and third). In other words, by selecting the position and number of coils for each phase, the connection type can be switched between a series type and multiple parallel types. Therefore, when applied to electric vehicles such as bicycles, motorcycles, so-called senior cars, wheelchairs, and automobiles, multiple gear switching (electronic gear) is possible without the need for mechanical gears. This configuration can be applied not only to the coreless motor according to the present invention, but also to cored motors.

[0071] The total number of coils for each phase is divided according to the number of switching stages (series (=1 parallel), multiple parallel patterns), but it is desirable to divide them evenly to prevent the generation of circulating current between the coils. For example, if the total number of coils is 24, it will be divided into 24 coils for series (1 parallel), and 12 coils for 2 parallel. Similarly, it can be divided evenly by dividing into 8 coils for 3 parallel, 6 coils for 4 parallel, and 4 coils for 6 parallel. If the number of divisions is further increased to 3 coils for 8 parallel, 2 coils for 12 parallel, and 1 coil for 24 parallel. By dividing the coils evenly in this way, there is no difference in the number of coils in parallel in each phase, so circulating current does not occur. For this reason, heat generation due to the generation of circulating current can be suppressed, and an increase in waste (loss) in energy (power) efficiency can be avoided.

[0072] Incidentally, the circuits shown in the above embodiments can be built into the motor 10. In particular, when the circuits are housed inside the motor, the internal space peculiar to a coreless motor can be effectively utilized. Furthermore, the motor 10 according to the present invention can maintain its function as a rotating electric machine even without the provision of the rotating shaft 14. This is possible because the rotating shaft 14 and the rotor 16 are not connected by a core, and can be realized, for example, by connecting the rotating shaft of an input / output device directly to the rotor. In such a configuration, the interior of the motor 10 is hollow, making it possible to more effectively utilize the internal space.

[0073] In the above embodiment, the electronic gear is mainly switched based on the rotation speed of the motor 10. However, when the motor 10 according to the present invention is applied to a propulsion power source for an electric vehicle, the vehicle speed (vehicle speed) of the electric vehicle to which the motor 10 is applied can be detected, and the electronic gear can be switched based on the detected vehicle speed. Note that the vehicle speed can be detected using a sensor (not shown) or the like, and various conventional (known) methods can be used.

[0074] [Application form] In each of the above embodiments, a circuit unit is provided for each single coil. However, the number of coils arranged between the circuit units is not limited to one. For example, by varying the number of coils arranged between the circuit units and devising the arrangement of the circuit units, it becomes possible to equalize the number of coils connected in series when connecting coils in parallel, and the range of characteristic changes due to the combination of coils connected in series and coils connected in parallel can be expanded.

[0075] For example, in a motor 10 having an actuation coil 18 configured as shown in FIG. 16, twelve coils (first coil to twelfth coil: U1-W1) are provided for each phase (U phase, V phase, W phase). 12As an example, the circuit units 20U1-20U5 in the U phase are arranged between coil U3 and coil U4, between coil U4 and coil U5, between coil U6 and coil U7, between coil U8 and coil U9, and between coil U9 and coil U10. 10 The circuit sections (20V1-20W5) are arranged in the same manner for the V-phase and W-phase.

[0076] The circuit section (20U1-20W5) is provided with ports a1, b1, a2, b2, c1, and c2. In the circuit section (20U1-20W5) having such ports, the ports a1 and b1 can be switched to and from the port c1, and the ports a2 and b2 can be switched to and from the port c2, and both are configured to be switched simultaneously.

[0077] Next, the relationship between the switching of the connection form of the operating coil 18 and the switching of the circuit units (20U1-20W5) in this embodiment will be described. Since the corresponding circuit units (20U1-20W5) in each phase are switched simultaneously, in the following description, the circuit units 20U1, 20V1, 20W1 will be referred to as circuit unit 20X1, the circuit units 20U2, 20V2, 20W2 as circuit unit 20X2, the circuit units 20U3, 20V3, 20W3 as circuit unit 20X3, the circuit units 20U4, 20V4, 20W4 as circuit unit 20X4, and the circuit units 20U5, 20V5, 20W5 as circuit unit 20X5.

[0078] In the motor of this embodiment, in the case of 1-parallel (series connection), the switching is set so that the a-port and the c-port are connected in all the circuit units 20X1-20X5. In addition, in the case of 2-parallel, the switching is set so that only the circuit unit 20X3 connects the b-port and the c-port. In addition, in the case of 3-parallel, the switching is set so that the circuit units 20X2 and 20X4 connect the b-port and the c-port. Furthermore, in the case of 4-parallel, the switching is set so that the circuit units 20X1, 20X3, and 20X5 connect the b-port and the c-port.

[0079] When the coils constituting each phase are arranged in a cylindrical shape, they take the form shown in FIG. 17. In the example shown in FIG. 17, coil U1 and coil U 12 The boundary between the coils U1 and U2 is the input / output terminal for power. 12 In the coils arranged in this manner, when the above-mentioned two parallel coils are implemented, the coils are divided (divided into two equal parts) in the circuit section 20U3, and the coils U1-U6 and the coils U7-U 12 In addition, when the above three parallel circuits are implemented, the coils are divided (into three equal parts) in the circuit sections 20U2 and 20U4, and the coils U1-U4, coils U5-U8, and coils U9-U 12 Furthermore, when the above four parallel circuits are implemented, the coils are divided (into four) in the circuit sections 20U1, 20U3, and 20U5, and the coils U1-U3, U4-U6, U7-U9, and U 10 -U 12 are connected in series to each other. Although FIG. 17 shows the coil arrangement for the U phase, the same applies to the V phase and the W phase.

[0080] FIG. 18 shows an example of a six-stage switching circuit using the present invention. In this example, three phases U, V, and W are used, and 12 coils are used for each phase, and six-stage switching is possible with the coil connection method being 1 parallel (i.e., series), 2 parallel, 3 parallel, 4 parallel, 6 parallel, and 12 parallel (2 or more in parallel). In the example shown in FIG. 18, a combination of relays as shown in the figure is used for simplicity of explanation, but as will be described later, the circuit device may be integrated using one or more switching elements (semiconductor elements) such as FETs. This is because by integrating the circuit device using semiconductor elements, it is possible to reduce the size and weight of the motor 10 itself and simplify the internal wiring. In the figure, a1, a2, b1, b2, c1, and c2 indicate ports (contacts), Lu1 to Lu12, Lv1 to Lv12, and Lw1 to Lw12 indicate coils, and Ku1 to Ku11, Kv1 to Kv11, and Kw1 to Kw11 indicate circuit sections (relays).

[0081] Port c1 and port c2 in the circuit section are switched at the same time, and if port c1 is connected to port a1, port c2 is connected to port a2 at the same time. In this connection form, the coils arranged on both sides of the circuit section are connected in series. Note that port a2 in the circuit section is an unused terminal (unconnected). On the other hand, if port c1 is connected to port b1, port c2 is connected to port b2 at the same time. In this connection form, the coils arranged on both sides of the circuit section are connected in parallel. If there are 11 such circuit sections, 1 parallel (1 parallel is in series), 2 parallel, 3 parallel, 4 parallel, 6 parallel, or 12 parallel can be selected as shown in the table in FIG. 19, depending on which circuit section is selected as a or b. Note that x in Kx1 to Kx11 in the table indicates u, v, and w (for example, Kx1 of the U phase becomes Ku1).

[0082] To rotate the motor, multiple phases (three phases in the above explanation) are required, but the switching method shown in the table is the same for each phase. The switching operation may be automatic or manual, and the essence of this embodiment is that multiple-stage switching is possible other than series. The switching operation is performed, for example, by selecting the number of stages using the gear switching operation means 30 in FIG. 27 (explained later), sending an instruction to select the stage to the controller 31, and the controller 31 sends an operation signal Sin to the shift register 32.

[0083] [Other than 3 phase: 2 phase and 5 phase examples] In the above embodiment, the actuating coil 18 has been described as being configured with three phases, U, V, and W. However, the motor 10 according to the present invention is characterized in that it allows multiple-stage circuit switching between series and parallel. Therefore, the actuating coil 18 is not limited to being configured with three phases, as long as it is configured with multiple phases.

[0084] An example of the case where the actuation coil 18 is configured with two phases is shown in Figs. 20 to 22. In the circuit diagram of Fig. 20, when the circuit section 20 is tilted toward the solid line side, the coils constituting the actuation coil 18 are connected in series, and when it is tilted toward the dashed line side, the coils are connected in parallel. Figs. 21 and 22 are explanatory diagrams that show the configuration of the actuation coil 18. In both figures, the coils are drawn with two types of lines, solid and dashed, to indicate two phases. Also, the mountain-shaped parts close to the permanent magnet 16a, indicated by S and N on the upper side of the figure, represent the coils that form the poles. Note that Fig. 21 shows a state in which the coils are connected in series, and Fig. 22 shows a state in which the coils are connected in parallel.

[0085] Next, an example of a case where the actuating coil 18 is configured with five phases is shown in Figs. 23 to 25. In the circuit diagram of Fig. 23, when the circuit section 20 is tilted toward the solid line side, the coils are connected in series, and when it is tilted toward the dashed line side, the coils are connected in parallel. Figs. 24 and 25 are explanatory diagrams that show the configuration of the actuating coil 18. In both figures, the coils are expressed with five types of lines to indicate five phases. Also, the mountain-shaped parts close to the permanent magnet 16a shown by S and N on the upper side of the figure represent the coils that form the poles. Note that Fig. 24 shows a state where the coils are connected in series, and Fig. 25 shows a state where the coils are connected in parallel.

[0086] [Prevention of short circuits in the switching circuit (circuit section 20)] If the series / parallel switching is a mechanical selection operation, then a short circuit will not occur. However, if a switching element or the like is used instead of a mechanical selection mechanism, then a momentary short circuit may occur depending on the timing, so measures must be taken. One such measure is to use a clock. Specifically, it is necessary to ensure that the series gate and the parallel gate are not turned ON (Hi) at the same time.

[0087] The relationship between the clock and the command signal when specific measures are taken, and a configuration example of the control unit for the circuit unit are shown in Figures 26 and 27. When a command signal from the gear switching operation means 30 is input to the controller 31, it is input from the controller 31 to the shift register 32 as a command signal Sin (serial in).

[0088] When the command signal Sin is input, the shift register 32 outputs command signals from the terminals Q0, Q1, and Q2. At this time, the shift register 32 adjusts the outputs from each terminal (Q0, Q1, and Q2) to have a shift as shown in FIG. 26 due to the action of the clock signal clk. Specifically, when Sin is L (Lo, the same below) and clk rises, Q0 becomes L, and when Sin is H (Hi, the same below) and clk rises, Q0 becomes H. On the other hand, in other cases, that is, when there is no change in Sin, the signal state remains L or H regardless of the rise of clk. A change is made to Q1 based on the signal of Q0. Specifically, when Q0 is L and clk rises, it becomes L, and when Q0 is H and clk rises, Q1 becomes H. And when there is no change in the signal of Q0, the previous state, that is, the state of L or H, is maintained. A change is made to Q2 based on the signal of Q1. Specifically, when Q1 is L and clk rises, it becomes L, and when Q1 is H and clk rises, Q2 becomes H. If there is no change in the Q1 signal, the previous state, that is, the L or H state, will be maintained, just like Q1.

[0089] The outputs from Q0 and Q2 are input to a NOR element 33, which outputs a command signal as EN (XNOR: exclusive NOR). In the NOR element 33, when the signals from Q0 and Q2 match, the output of the command signal is permitted, and when the signals do not match, the output of the command signal is not permitted. Specifically, when the command signal output from Q0 is L and the output from Q2 is also L, the gate becomes H and the output of the command signal is permitted. Similarly, when the output from Q0 is H and the output from Q2 is Hde, the gate becomes H and the output of the command signal is permitted. On the other hand, when the command signal output from Q0 is L and the output from Q2 is H, or when the output from Q0 is H and the output from Q2 is L, the gate becomes L and the output of the command signal is not permitted.

[0090] The command signal output from Q1 in the shift register 32 is input to the AND element 35 via the NOT element 34, and is also input directly to the AND element 36. Since the output signal from the NOT element 34 is the opposite of the input signal (if the command signal output from Q1 is L, the output from the NOT element 34 is H, and if the command signal from Q1 is H, the output from the NOT element 34 is L), the AND element 35 and the AND element 36 each receive an opposite command signal as the command signal from Q1.

[0091] The AND element 35 and the AND element 36 each output a command signal of H only when the command signal from Q1 and the output signal from the NOR element 33 become H at the same time. As described above, the AND element 35 and the AND element 36 receive opposite signals (L or H) as the command signal from Q1, so that they do not output a command signal of H at the same time. In addition, since there is a difference in the switching timing of the command signals from Q0, Q1, and Q2 in the shift register 32, the switching timing of the output signal from the NOR element 33 and the switching timing of the command signal from Q1 do not coincide. Therefore, there is no risk of the switching timing of the command signals from the AND element 35 and the AND element 36 coinciding.

[0092] The outputs from the AND element 35 and the AND element 36 are input to blocks 37, 38, and 39 that configure the circuits of the respective phases. The block 37 indicates the U-phase block, the block 38 indicates the V-phase block, and the block 39 indicates the W-phase block. In the blocks 37, 38, and 39, G1s to which the command signal output from the AND element 35 is input is an input terminal for a switching signal to the gate serial (series side), and G1p to which the command signal output from the AND element 36 is input is an input terminal for a switching signal to the gate parallel (parallel side). As described above, the command signals from the AND element 35 and the AND element 36 do not match, and a shift occurs in the switching timing of L and H. For this reason, as shown in FIG. 26, there is no timing when G1s and G1p are simultaneously ON (Hi), and no short circuit occurs. The numerals "1" in G1s and G1p indicate the numbers of the respective circuit parts, and in the case of the terminals in Kx11 in the circuit part in FIG. 19, they can be indicated as G11s and G11p, respectively.

[0093] FIG. 28 shows an example of a circuit diagram constituting a block. The example shown in FIG. 28 is an example of a circuit diagram in a block constituting a U phase, but the blocks constituting a V phase and a W phase have a similar configuration. For example, for Lu1h, Lv1h in the case of the V phase, Lw1h in the case of the W phase, and Lv2h and Lw2h in the case of Lu2h. Furthermore, Lu1l becomes Lv1l and Lw1l, and Vu becomes Vv and Vw, respectively. In the example shown in FIG. 28, a switching element and a FET (field effect transistor) element 40 corresponding to a circuit part are shown, but the use of a switching element in implementing the present invention is not limited to the use of a FET element. [Industrial Applicability]

[0094] In the above embodiment, the number of coils and the number of circuit parts are limited, but the number of coils and circuits may be increased or decreased to increase the number of combinations when the coils are connected in series and in parallel. In addition to increasing the number of combinations of coil connection forms, the appropriate rotation speed and torque according to the application may be selected and the combination of coil connection forms may be limited. For example, when applying to an application where it is desired to increase the rotation speed rather than the torque of the initial operation such as an electric tool, it is sufficient to select and switch between a combination of coils that can perform characteristic operation in the high rotation range, such as 4 parallel and 3 parallel.

[0095] In addition, in the above embodiment, the circuit unit 20 is shown mechanically in order to make it easier to understand the switching of the coil connection configuration, but the circuit unit 20 may be provided with a similar function by a semiconductor chip.

[0096] In addition, in the above-mentioned embodiments, the actuator coil 18 is described as being cylindrical in shape. However, the motor according to the present invention may also include an actuator coil arranged in a disk shape.

[0097] In the above embodiment, the number of coils is equalized when parallel connection is performed, and multiple-stage switching connection is possible. Therefore, although the number of coils constituting each phase is described as an even number in each embodiment, even if the number of coils constituting each phase is an odd number, it can be considered as part of the present invention.

[0098] For example, as shown in Figures 29 and 30, if the number of coils in each phase that constitutes the operating coil 18 is three, it is possible to switch between a connection format in which the three coils are connected in series (one parallel in the above embodiment: see Figure 29) and a connection format in which the three coils are connected in parallel (three parallel in the above embodiment: see Figure 30). [Explanation of symbols]

[0099] 10... Motor, 12... Housing, 12a... Bearing, 14... Rotating shaft, 16... Rotor, 16a... Permanent magnet, 16b... Inner yoke, 16c... Outer yoke, 18... Operating coil, 18a... Conductive wire, 18b... Enamel layer, 18c... Outer layer, 20 (20U, 20V, 20W)... Circuit section, 22... Control section, 30... Gear switching operation means, 31... Controller, 32... Shift register, 33... N OR element, 34...NOT element, 35...AND element 36...AND element, 37...U phase block, 38...V phase block, 39...W phase block, U1...first coil, U2...second coil, U3...third coil, U4...fourth coil, V1...first coil, V2...second coil, V3...third coil, V4...fourth coil, W1...first coil, W2...second coil, W3...third coil, W4...fourth coil.

Claims

1. A coreless rotating electric machine comprising: a housing; a cylindrical non-rotating operating coil, one end surface of which is supported in a cantilever manner by a stator; a rotor having a magnet attached to a yoke located on a surface facing the operating coil and spaced apart from the operating coil; and a rotating shaft connected to the rotor and disposed on an inner circumferential side of the operating coil, The actuating coil is made up of a plurality of phases, each of which is made up of a plurality of coils, and is provided with a circuit section for switching the connection of the coils constituting each phase between series and parallel, and the circuit section performs a plurality of stages of switching for the parallel switching, which selects the position and number of the coils constituting each phase as the rotation speed increases, 1. A coreless rotating electric machine comprising systems having different motor characteristics within a single coreless rotating electric machine.

2. 2. A coreless rotating electrical machine according to claim 1, A coreless rotating electric machine comprising: a control unit that switches the circuit unit so as to increase the number of coils connected in series on the low rotation side and to increase the number of coils connected in parallel on the high rotation side relative to a predetermined threshold rotation speed.

3. A coreless rotating electrical machine according to any one of claims 1 to 3, The actuation coil is made up of three phases, U, V, and W, each phase having four coils; A coreless rotating electric machine characterized by configuring a transmission mechanism that corresponds to low gear, second gear, and top gear, in sequence, starting from 1 parallel, by switching the system between 1 parallel in which the four coils of each phase are connected in series, 4 parallel in which they are connected in parallel, and 2 parallel between 1 parallel and 4 parallel as the rotation speed increases.

4. 4. An electric vehicle comprising the coreless rotating electric machine according to claim 1 as a driving force for said electric vehicle.

5. The electric vehicle according to claim 4, This electric vehicle is characterized by the fact that it switches to series when the vehicle starts, switches to parallel after starting, detects the rotation speed of the coreless rotating electric machine, automatically switches stages according to the rotation speed, and returns to series when the speed decreases.

6. The electric vehicle according to claim 5, An electric vehicle that uses regenerative braking to charge the power source when going downhill.

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