Rotating electrical machinery

Abstract

To provide a rotary electrical machine with which it is possible to maintain a prescribed torque at high revolution time and heighten responsiveness at characteristics switching time.SOLUTION: A rotary electrical machine comprises a permanent magnet, a stator, and a stator coil, the stator coil being composed of a plurality of phases, with two short coil elements D, C and two long coil elements A, B, the length of which is twice the short coil elements, used in combination allowing for use of a total of six coil elements in terms of the short coil elements. Thus, it is made possible to switch between a first pattern in which the number of contacts between coil elements is reduced compared to the case of using a total of six short coil elements, and all of used coil elements A, B, C, D are connected in series, a second pattern in which two short coil elements C, D are connected to form one long coil element, and two long coil elements A, B are arranged in parallel, and a third pattern in which a combination of the short coil elements C, D and two combinations of the long coil elements A, B are arranged in parallel, or two long coil elements A, B in parallel and two short coil elements C, D in parallel are connected in series.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rotating electrical machine, and more particularly to a rotating electrical machine suitable for efficient operation.

Background Art

[0002] As a technique for changing the characteristics of a motor as a rotating electrical machine, as disclosed in Patent Document 1 and Patent Document 2, it has been proposed to switch the connection form of the internal winding. For example, Patent Document 1 is a technique related to a motor for a machine tool, and a coil composed of three phases is used as a stator, and each coil constituting each phase is composed of a plurality of coil elements having different numbers of turns. Then, at high speed rotation, a configuration is adopted in which one to a plurality of coil elements are selectively connected in series so that the total number of turns of the coil becomes small, and at low speed rotation, the total number of turns of the coil becomes large.

[0003] Further, Patent Document 2 discloses a technique related to a motor mainly for a power tool or a starter generator for an automobile. The motor disclosed in Patent Document 2 also uses a coil composed of three phases as a stator, similar to the motor disclosed in Patent Document 1. And each phase is composed of a plurality of coil elements, and a switch device capable of switching the connection of the plurality of coil elements constituting each phase in series or in parallel is provided. By adopting such a configuration, in series connection, the magnetic field excited by the coil becomes strong and the torque can be improved, and in parallel connection, the magnetic field becomes weak, so that high speed rotation can be realized.

[0004] Further, Patent Documents 3 and 4 describe that in a coreless motor having a plurality of phases, the characteristics of the motor can be made different by determining the connection method of each phase as series or parallel. Furthermore, Patent Document 5 describes that in a motor having a fixed coil, when switching the connection method of the coil elements constituting the three-phase coil between series and parallel, a circuit is used.

Prior Art Documents

[0005] [Patent Document 1] Patent No. 3596711 [Patent Document 2] Special Publication No. 2010-537621 [Patent Document 3] Japanese Patent Publication No. 2014-121102 [Patent Document 4] Japanese Patent Publication No. 2019-54628 [Patent Document 5] Japanese Patent Publication No. 2011-229221 [Overview of the project] [Problems that the invention aims to solve]

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

[0007] However, the technology disclosed in Patent Document 1 involves a substantial change in the number of coil turns, which may lead to a drastic decrease in torque at high rotational speeds. Furthermore, the technology disclosed in Patent Document 2 has a large self-inductance due to the influence of the iron core, raising concerns about a time lag between switching and characteristic changes.

[0008] Furthermore, the coreless motors disclosed in Patent Documents 3 and 4 have small capacities. Therefore, the concept of switching the motor's characteristics during use could not arise. Also, it has been common knowledge among those skilled in the art that increasing the capacity of a coreless motor could lead to deformation of the stator coil due to the counter-torque generated when rotating the rotor, making it unsuitable for high-capacity applications. Therefore, it was common technical knowledge that the cored motor technology disclosed in Patent Document 5 could not be directly applied.

[0009] Therefore, the present invention aims to solve the above problems, break away from conventional technical norms, provide a rotating electric machine that can be applied to increasing the capacity of coreless motors, maintain a predetermined torque even at high rotational speeds, and improve responsiveness during characteristic switching. [Means for solving the problem]

[0010] In the following explanation, a coil element refers to a coil unit (part) that forms a coil body, and each coil element is identical in shape and material. To achieve the above objective, the present invention provides a rotating electric machine comprising a permanent magnet, a stator, and a stator coil, wherein the stator coil consists of multiple phases, and each phase is configured using two short coil elements and two long coil elements twice the length of the short coil elements, thereby using the equivalent of six short coil elements, reducing the number of coil element indirection points compared to using six short coil elements, and is characterized by the ability to switch between the following connection patterns: a first pattern in which all coil elements used are connected in series, a second pattern in which two short coil elements are connected in series to form a coil element equivalent to one long coil and two long coil elements are connected in parallel, and a third pattern in which two sets of coil elements, each consisting of a short coil element and a long coil element connected in series, are connected in parallel, or two long coil elements connected in parallel and two short coil elements connected in parallel are connected in series. Furthermore, it is preferable that the maximum rotational speed in the relationship between rotational speed and torque be set to the second pattern, the rotational speed at startup to the first pattern, and the intermediate rotational speeds to be obtained using the third pattern. In addition, it is preferable to set the rotational speed intervals from zero to the first pattern, from the first to the third pattern, and from the third to the second pattern to be substantially the same width when switching between them, as this improves usability, ease of operation, and user comfort for the operator. Furthermore, the long coil element may be a single coil element adjusted for long coil use from the beginning, or it may be a series of short coil elements arranged in series and directly connected (i.e., contactless) without a switch interposed between their joints.

[0011] Furthermore, the rotating electric machine according to the present invention for achieving the above objective comprises a permanent magnet, a stator, and a stator coil, wherein the stator coil consists of multiple phases, and for each phase, the long coil elements do not necessarily have to be twice the length of the short coil elements, but may consist of N long coil elements, each N times the length of the short coil elements, and N short coil elements (where N is an integer).

[0012] The most suitable rotating electric machine to which this invention applies is a coreless motor, because it does not have an iron core like a cored motor, resulting in lower inductance. In that sense, even among cored motors, a slotless type motor without iron core teeth is also suitable.

[0013] Furthermore, although the rotating electric machine of the present invention described above uses two short coil elements, multiple elements may be connected in series to a length equivalent to that of a long coil element. Also, the long coil elements are not limited to two, and multiple elements may be provided.

[0014] In short, by using both short and long coil elements (a concept that includes directly connecting two short coils without contacts), the number of contacts (number of switches) between coil elements can be reduced compared to a system composed entirely of short coil elements (i.e., conventionally used coil elements).

[0015] Ideally, a switching pattern corresponding to the total number of coil elements could be provided, but in this invention, some of the possible patterns are intentionally left unused (unused patterns are possible because the number of coil contacts is reduced). Reducing the number of contacts reduces the risk of defects and failures, and also leads to cost reduction. From the perspective of T (torque)-N (rotational speed) characteristics, it is comfortable and convenient for the driver if the rotational speed switches with a nearly small range (interval: difference). The inventors thought that by aiming to average out such switching rotational speed intervals, it would be acceptable to thin out the fine coil patterns. Furthermore, the maximum rotational speed corresponding to the total number of coil elements (the total length of the coils mentioned above) is not normally used (left unused), and the upper limit of the range possible with the coil combination of this invention should be set as the maximum rotational speed in normal use.

[0016] Also, in the rotary electric machine having the above-described characteristics, the stator coil preferably has a cylindrical structure. By adopting such a configuration, it is possible to provide a gap in the internal space of the motor. Therefore, it is also possible to effectively utilize the internal space of the motor. Furthermore, due to its deformation resistance, even when the motor capacity is increased, it is possible to prevent the deformation of the stator coil due to the reaction torque when the rotor rotates.

[0017] Also, in the rotary electric machine having the above-described characteristics, the stator coil preferably consists of three phases of U, V, and W. By having such characteristics, it is possible to avoid complication of the number of coils and circuits, and to reduce the manufacturing cost during mass production.

[0018] Also, in the rotary electric machine having the above-described characteristics, the coil is preferably formed using Litz wire. By having such characteristics, it is possible to obtain the strength for maintaining the shape of the stator coil, and since there is no need to use iron plates or copper plates for the stator coil, it is possible to reduce the self-inductance.

Effect of the Invention

[0019] According to the rotary electric machine having the above-described characteristics, it is possible to cope with an increase in capacity that is not in the common technical knowledge of the prior art, to maintain a predetermined torque even at high speeds, and to improve the responsiveness during characteristic switching while also reducing the number of contact points between coil elements, thereby reducing the risk of defects and failures and contributing to cost reduction.

Brief Description of the Drawings

[0020] [Figure 1] It is a diagram for explaining the relationship between the circuit configuration pattern of the stator coil and the T-N characteristics in the rotary electric machine according to an embodiment of the present invention. [Figure 2] It is a diagram for explaining the relationship between the circuit configuration pattern of the stator coil and the T-N characteristics in the rotary electric machine obtained by arranging the embodiment of FIG. 1. [Figure 3] It is an example of a connection circuit diagram of a coil and a switch in the embodiment of FIG. 1. [Figure 4] It is another example different from FIG. 3 of the connection circuit diagram of the coil and the switch in the embodiment of FIG. 1. [Figure 5] It is a figure showing circuit diagrams of the proposal of FIG. 3 in three phases of U, V, and W combined. [Figure 6] It is a side sectional view for explaining a structural example of the rotating electrical machine of the present invention. [Figure 7] It is a system diagram for operation of a rotating electrical machine including a coil switching device applicable to each embodiment of the present invention. [Figure 8] It is a figure showing a configuration example of a control unit that outputs a command signal to a circuit section using a switching element applicable to each embodiment of the present invention. [Figure 9] It is a figure for explaining an example of a connection pattern of a stator coil according to another embodiment of the present invention. [Figure 10] It is a figure for explaining an example of a connection pattern of a stator coil according to still another embodiment of the present invention. [Figure 11] It is a figure showing a coil element pattern according to another embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments of the rotating electrical machine according to the present invention will be described in detail with reference to the drawings. Note that as the embodiments shown below, a motor will be described as an example of the rotating electrical machine.

[0022] [Basic Configuration] First, the basic configuration of the motor device 10 according to this embodiment will be described with reference to Figure 6. The motor device 10 according to this embodiment is a so-called coreless motor, consisting of a housing 12, a rotating shaft 14, a stator coil 18, and a rotor 16. The housing 12 is an element that constitutes the outer shell and houses the rotating shaft 14, the stator coil 18, and the rotor 16 in its internal space. The rotating shaft 14 is positioned to penetrate the housing 12 and is rotatably supported by a bearing 12a provided at the intersection with the housing 12.

[0023] The stator coil 18 is configured to form a cylindrical shape with a group of coil elements divided into multiple phases (in this embodiment, three phases: U-phase, V-phase, and W-phase). The U-phase, V-phase, and W-phase that make up the stator coil 18 each consist of multiple coil elements that constitute poles. The stator coil 18 with this configuration is supported at one end face by a stator (in the example shown in Figure 6, the housing 12), which is a fixed member.

[0024] The rotor 16 also has a cylindrical outer yoke 16c, an inner yoke 16b, and a permanent magnet 16a, with one end face connected to the rotating shaft 14. The outer yoke 16c is an element located on the outer circumference side of the stator coil 18 (radially outward side with the center of the cylinder as the base point), and the inner yoke 16b is an element located on the inner circumference side of the stator coil 18. Furthermore, in the motor device 10 according to this embodiment, the permanent magnet 16a is configured to be provided on the inside of the outer yoke 16c and on the surface facing the stator coil 18.

[0025] In a coreless motor with this configuration, the power source and the rotating shaft 14 are separated, making it possible to obtain a large output and torque relative to the size of the motor. In addition, since the stator coil 18 does not have an iron core, its self-inductance can be kept low.

[0026] Furthermore, in each embodiment of this specification, when constructing the stator coil 18, Litz wire is used for the winding and the shape is formed by coating with an insulating layer. The Litz wire is composed of a bundle of multiple conductive fine wires, and the outer circumference of each conductive fine wire is covered with an enamel layer. In addition, an outer sheath layer of fibrous material such as glass fiber is provided on the outer circumference of the conductive fine wires (conductive wires as a bundle).

[0027] This configuration helps to suppress the generation of eddy currents (eddy current loss) caused by the use of iron or copper plates to maintain the shape, thereby contributing to a reduction in self-inductance.

[0028] [First Embodiment] First, the detailed configuration of the motor device 10 according to the first embodiment will be described with reference to Figures 1 to 5. The basic configuration of the motor device 10 according to this embodiment is the same as that shown in Figure 6.

[0029] The stator coil 18 according to this embodiment is characterized by the use of both short coil elements and long coil elements. In this embodiment, the long coil elements are twice the length of the short coil elements. Here, the terms "short coil elements" and "long coil elements" are used for convenience in the following explanation, but essentially, in this application, the coils that are normally used are called short coil elements, and the coil elements that are twice the length are called long coil elements in this embodiment. In this embodiment, a total of four coil elements are used: two short coil elements and two long coil elements.

[0030] For example, suppose long coil elements A and B each have 20 turns, and short coil elements C and D each have 10 turns (A and B are twice as long (turns) as C and D). In this case, the two long coil elements and two short coil elements will form a coil body with the potential capacity of six short coil elements in total. However, since the total number of coil element materials is four and the number of contacts is small, as shown in Figure 1, there are three possible patterns: one where A, B, C, and D are all in series with a back EMF of 6V and a resistance of 6Ω (assuming 1V and 1Ω per coil element); one where A and C are in series (equivalent to three short coil elements) and B and D are in series (equivalent to three short coil elements) in parallel with a voltage of 3V and a resistance of 1.5Ω; and one where A (equivalent to two short coil elements), B (equivalent to two short coil elements), and C+D are connected in series and then connected in parallel with a voltage of 2V and a resistance of 0.67Ω. If the long coil elements A and B were short coil elements, it would be possible to create a pattern where all six coil elements are in parallel, but in this invention, long and short coil elements are used in combination, so it is not possible to create a pattern where all six coil elements are in parallel.

[0031] The TN characteristic diagram in Figure 1 shows the characteristics of these three patterns. Since a motor is configured for each pattern, in this invention, three patterns of motors are inherent in a single motor device, and the motor transforms into three different types by switching the connection of the coil elements. In Figure 1, the vertical axis represents rotational speed, which corresponds to speed, and the horizontal axis represents torque. The scales on the vertical and horizontal axes are equally spaced, but specific numbers have been omitted for illustrative purposes (for example, the top mark on the vertical axis could be set to 2000 rpm or 10000 rpm, or it could be replaced with speed. The same applies to the horizontal axis).

[0032] In the first pattern, when two long and two short coil elements are connected in series, the maximum rotational speed of the motor constructed in the first pattern is 6V / 6V=1, as shown by the line from scale 1 to torque scale 1 on the vertical axis. Next, in the second pattern, when two coil elements, each consisting of one long coil element and one short coil element connected in series, are connected in parallel, the back electromotive force is 3V. Therefore, the maximum rotational speed of the motor constructed in the second pattern is 6V / 3V=2, as shown by the line connecting scale 2 and torque scale 2 on the vertical axis in Figure 1. Finally, in the third pattern, when a coil element consisting of short coil elements C+D connected in series is connected in parallel with long coil elements A and B, the back electromotive force is 2V. Therefore, the maximum rotational speed of the motor constructed in the third pattern is 6V / 2V=3, as shown by the line connecting scale 3 and torque scale 3 on Figure 1. When three patterns are created in this way, the interval between the maximum rotational speeds of the motor in the first pattern and the motor in the second pattern is substantially equal to the interval between the maximum rotational speeds of the motor in the second pattern and the motor in the third pattern.

[0033] Furthermore, when the motor device 10 is configured by switching between these patterns, there is no motor that has the maximum rotational speed at the highest scale position on the vertical axis, which would be equivalent to 6 parallel motors as originally assumed by the 6 coil elements (6 short coil elements). However, the interval (difference) between the maximum rotational speed of the 6-parallel equivalent motor and the maximum rotational speed of the third pattern motor is significantly larger than the interval between the maximum rotational speeds of the first to second and second to third pattern motors, resulting in a greater switching shock for both the operator and the device. For this reason, in this embodiment, by eliminating the switching to the 6-parallel equivalent motor, the shock to the operator and the device caused by the gear function switching is eliminated, enabling smooth device operation.

[0034] As shown on the vertical axis of the characteristic diagram in Figure 1, the motors to be used are selected such that the interval between the maximum rotational speeds of the motors (including the interval from zero rotational speed in the case of the maximum rotational speed of all motors connected in series) is substantially approximate (within the range of an interval (difference) of (1 ± 0.5) times the maximum rotational speed when all coil elements are connected in series), and motors that do not meet this condition may be left unused. For example, if it is less than 0.5 times, the switching will be too fine and the switching control will become complicated, but in practice, it is not necessary to make it that complicated. In this way, if the switching interval corresponding to the maximum rotational speed is substantially equal, the subjective burden on the driver is reduced. Furthermore, uniform switching intervals also reduce the burden on the equipment.

[0035] Figure 2 illustrates an alternative to the first embodiment. In the first embodiment, the long coil element is wound to twice the length of the short coil element from the beginning. However, in the example in Figure 2, the long coil element is not used as a separate material, and is entirely composed of ordinary coils (which have been referred to as short coil elements in this application). Two of these ordinary coil elements (short coil elements) are connected in series without contacts and are used as the equivalent of the long coil element in the first embodiment. Furthermore, the 6-parallel equivalent of the short coil elements (connecting all six short coil elements in parallel) is not used, nor is the 4V pattern (consisting of four short coil elements connected in series and an unused coil element). As a result, the configuration is the same as the first embodiment, and the same effect can be obtained (this will be explained below as an example common to both Figure 1 and Figure 2).

[0036] The circuit diagrams of the switches and coil elements in this embodiment are shown in Figure 3 and Figure 4 for each phase. In the example in Figure 3, 13 switches are required for each phase, but the number of switches is reduced, and the difference (interval) in the maximum motor rotation speed caused by each switching is approximated. In the example in Figure 4, 11 switches are required for each phase, but the number of switches can be reduced even further than in the example in Figure 3. If there are 6 coil elements of the same length (6 coil elements), 15 switches are required. On the other hand, if there are 4 coil elements of the same length (4 coil elements), 9 switches are required, but this example requires fewer switches than the original 6 coil elements.

[0037] Figure 5 shows the same design as in Figure 4, but with the U, V, and W phases added together. The blank squares indicate switches. By the way, the above explanation uses two short coil elements and two long coil elements, but the present invention is not limited to this. In short, it is characterized by using a combination of a normal coil element (= short coil element) and a coil element twice the length of a normal coil element (= long coil element) in order to reduce the number of contacts. Therefore, the number of each type of coil element is not limited, but when using them in combination, connection measures should be taken to prevent the generation of circulating current.

[0038] [effect] With a motor device 10 having this configuration, a predetermined torque can be obtained even in the high rotation range. Furthermore, when applied to coreless motors or slotless motors, the self-inductance can be kept low because the coil does not have an iron core, and the responsiveness from switching by connection switching by the circuit section to characteristic switching can be improved. And above all, since the number of contacts is small, it reduces the causes of defects and failures and contributes to cost reduction.

[0039] Generally, there is a trade-off between increasing the torque of a motor and increasing its maximum rotational speed. Increasing torque lowers the maximum rotational speed, and increasing the maximum rotational speed lowers the maximum torque. Conventionally, efforts have been made to increase rotational speed by increasing the voltage of the power supply and increase torque by increasing the current of the power supply. However, these control methods have safety issues and technical limitations. The inventors have therefore solved these conventional problems by considering an electrically automatic switching method for motors with different characteristics. By employing such a method, it is possible to use a single motor device while enabling multiple stages of circuit switching (switching of coil element connections by a coil switching device), such as Low gear, 2nd gear, and Top gear, thereby achieving the same effect as automatically switching between multiple motors with different characteristics.

[0040] Here, the Low gear offers high torque and low rotational speed, allowing high torque to be generated with a small current. Increasing rotational speed in the Low gear requires high voltage, but since the Low gear operates at low rotational speeds, high voltage is not necessary. The 2nd gear offers medium torque and medium rotational speed, while the Top gear offers low torque and high rotational speed (high rotation is possible with low voltage). Obtaining high torque in the Top gear requires a large current, but since the Top gear operates at low torque, a large current is not necessary.

[0041] By adding a coil element switching function to the motor in this way, a single motor unit can handle various driving scenarios. Consequently, it becomes unnecessary to increase the driver's voltage output and current output, reducing overload on the motor unit and suppressing rapid temperature increases in the motor unit.

[0042] As described above, the motor device 10 according to the present invention enables three or more characteristic switching stages by selecting the position and number of coil elements for each phase, thereby switching between a series Lo state and multiple parallel (e.g., second, third) or a mixture of series and parallel connections of the coil elements. In other words, by selecting the position and number of coil elements 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 mobility scooters, wheelchairs, and automobiles, it becomes possible to perform a function equivalent to multiple gear switching stages (switching of coil element connections) 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 the cored motor.

[0043] When the motor device 10 according to the present invention is applied to the propulsion power of an electric vehicle, the vehicle speed of the electric vehicle to be applied is detected by an encoder or resolver, and the connection switching of the coil elements is applied based on the detected vehicle speed value. For vehicle speed detection, sensors not shown may be used, and various conventional (known) methods can be used. The timing of the connection switching of the coil elements is performed by a coil element connection pattern switching device 80 (see Figure 7) which has been set to switch timing based on various speed detections.

[0044] Figure 7 shows the system diagram illustrating the connections between the controller 31, driver 40, coil element connection pattern switching device 80, and motor device 10. First, the controller 31 determines the torque output from the motor device 10 based on throttle information and speed information. Throttle information is the throttle opening; for example, it is 0% when the throttle is closed and 100% when the throttle is full. The controller 31 automatically or manually selects the gear value. The motor current is calculated from the selected gear value and torque value. Torque constant information for each gear is provided for the motor current calculation.

[0045] The driver 40 controls the motor device 10 so that the motor current value matches the command value from the controller 31, and also provides the controller 31 with the rotational speed (velocity) N of the motor device 10 as speed information. Regarding gear selection, a low gear is used when the rotational speed is low, and a higher gear is used when the rotational speed is high. Torque is determined according to a torque map pre-stored in the controller 31. This torque map consists of, for example, torque values ​​for multiple throttle states and multiple speeds (rotational speeds), and the torque that should actually be output is calculated by interpolation calculation from the actual throttle state, speed and this torque map. For example, the torque that should be output for all six types of throttle information and speeds—when the throttle is closed (0%), 20% open, 40% open, 60% open, 80% open, and full throttle (100%)—is stored in the controller 31 as a torque map. The controller 31 then calculates the torque value from the speed (rotational speed) N, the throttle information and this torque map. If the throttle value is anything other than the six types mentioned above (0%, 20%, 40%, 60%, 80%, 100%), the torque value is calculated using interpolation.

[0046] As described above, gear switching is performed by switching the coil element connection pattern using the coil element connection pattern switching device 80. In this way, the gears are switched according to the rotational speed of the motor device 10.

[0047] The controller 31 calculates the current value required for each gear to produce the predetermined torque to be output and instructs the driver 40 accordingly. The current command to the driver 40 is executed simultaneously with the gear switching instruction, so the output torque fluctuation during gear switching is very small, and smooth switching is achieved. In other words, a current command that does not change the torque before and after switching is given simultaneously with the switching, resulting in smooth switching. For example, assuming a system where the torque constant is 0.4 Nm / A in 1st gear and 0.2 Nm / A in 2nd gear, if the torque to be output in 1st gear is 1 Nm, the controller 31 instructs the driver 40 to issue a current command of 2.5 A. If the rotational speed increases and it becomes necessary to switch to 2nd gear, the controller 31 changes the current command given to the driver 40 from 2.5 A to 5 A at the same time as the switching instruction. As a result, the torque output from the motor device 10 is maintained at 1 Nm before and after switching, and smooth switching is achieved.

[0048] Incidentally, the circuit shown in the above embodiment can be built into the motor device 10. When the circuit is housed inside the motor device 10, the internal space unique to coreless motors can be effectively utilized. Furthermore, a coreless motor can maintain its function as a rotating electric machine even without a rotating shaft 14. This is possible because the rotating shaft 14 and the rotor 16 are not connected by a core, and can be achieved, for example, by directly connecting the rotating shaft of an input / output device to the rotor 16. With such a configuration, the inside of the motor device 10 becomes a hollow structure, making it possible to utilize the internal space more effectively.

[0049] Furthermore, in the above embodiment, the switching of the coil element connection pattern by the coil element connection pattern switching device 80 is mainly described based on the rotational speed of the motor device 10. However, when the motor device 10 according to the present invention is applied to the propulsion power of an electric vehicle, the vehicle speed (vehicle speed) of the electric vehicle to which it is applied can be detected, and the switching of the coil element connection pattern switching device can be performed based on the detected vehicle speed value. The detection of vehicle speed can be done using a sensor or the like (not shown), and various conventional (known) methods can be used.

[0050] Multiple phases (three phases in the above description) are required to rotate the motor device 10, but the switching method is the same for each phase. The switching operation can be automatic or manual, and the essence of this embodiment is that it is possible to switch between three or more stages. For example, the switching operation involves selecting the number of stages using the system in Figure 7 and the gear switching operation means 30 in Figure 8, sending the selection instruction to the controller 31, and the controller 31 sending the operation signal Sin to the shift register.

[0051] The circuit mechanism used in the embodiment of the present invention will be explained with reference to Figure 8. Figure 8 shows an overall view of the circuit configuration and illustrates an example of a circuit diagram that constitutes a block. Note that the example shown in Figure 8 is an example of a circuit diagram for a block that constitutes the U phase, but the blocks that constitute the V phase and W phase have a similar configuration. For example, Lu1h becomes Lv1h in the case of the V phase and Lw1h in the case of the W phase, and Lu2h becomes Lv2h and Lw2h. Also, Lu1l becomes Lv1l and Lw1l, and Vu becomes Vv and Vw, respectively.

[0052] In the above embodiment, the number of coil elements and circuit sections is limited, but the number of coils and circuits may be increased or decreased to increase the number of combinations when connecting coils in series and parallel. In addition to increasing the number of combinations of coil element connection configurations, the appropriate rotational speed and torque may be selected according to the application, and the combinations of coil connection configurations may be limited accordingly. For example, when applying to applications where it is desired to achieve a rotational speed greater than the initial torque of power tools, it is possible to select and switch between coil combinations that enable characteristic operation in the high-speed range.

[0053] Furthermore, in the above embodiment, the circuit section (switch) is shown mechanically to make it easier to understand the switching of the coil element connection configuration, but the switch may also be provided with a similar function by using a semiconductor chip.

[0054] Furthermore, in the above embodiments, the stator coil 18 was described as being cylindrical. However, the motor device 10 according to the present invention can also include a configuration in which the stator coil is arranged in a disc shape, and it is not limited to coreless motors but can be extended to brushless motors including slotless motors. Although slotless motors are cored motors, they do not have iron teeth, so there is no iron loss, and the inductance is small, similar to coreless motors.

[0055] Figure 9 illustrates an example of coil element connection patterns that combine long and short coil elements to produce 10 coil elements in terms of short coil elements. Patterns (A), (E), (J), and (N) each consist of one long coil element and eight short coil elements; patterns (B), (F), (G), (K), and (O) each consist of two long coil elements and six short coil elements; patterns (C), (H), (L), and (P) each consist of three long coil elements and four short coil elements; and patterns (D), (I), (M), and (Q) each consist of four long coil elements and one short coil element. In each case, the long and short coil elements are connected as shown in the diagram. Note that switches are omitted in the diagrams for each pattern.

[0056] The coil element connection pattern of the present invention is not limited to the pattern shown in this figure, but it is essential to use both short coil elements and long coil elements (including cases where two short coil elements are directly joined without contacts to form a single coil element), and the long coil elements are not disassembled for use. As a result, the number of contacts and switches is reduced, but the gear switching width obtained for switching control is the equivalent number of short coil elements in total (i.e., 10 coil elements in the example of Figure 9).

[0057] In the above example, the length of the long coil element is set to twice the length of the short coil element. However, the present invention is characterized by the use of coil elements of different lengths in combination to reduce contacts, and is not limited to setting the length of the long coil element to twice the length of the short coil element. However, using an arbitrary number may raise concerns about circulating current. Therefore, the ratio of the length of the short coil element to the length of the long coil element is 1:N, and the use of N long coil elements and N short coil elements is also within the scope of the present invention. For example, in Figure 10, three short coil elements correspond to the length of one long coil element. In this case, the combination of three short coil elements and three long coil elements allows for switching between patterns as shown in Figure 10.

[0058] Figure 11 shows an example of 12 coil elements, where a-l are coil elements and sw1-sw27 are switches. Coil elements a, b and coil elements g, h do not have contacts (switches) between them; they are directly connected by solder or formed from the beginning with twice the length of the short coil element.

[0059] Although only the box is depicted for each switch, each has an opening and closing function. If all nine switches sw1 to sw9 on the center line are turned ON (open) and all the remaining switches are turned OFF (closed), the back EMF will be 12V (assuming 1V per coil element). In this way, by selecting the opening and closing of sw1 to sw27, it is possible to switch between many ways of connecting the coil elements. However, even in this case, the 12-parallel configuration, where all 12 coils are connected in parallel, is not used, and the number of contacts can be reduced by using coil elements with a large number of turns (equivalent to long coil elements).

[0060] Furthermore, if we assume that the maximum value of the vertical axis (corresponding to rotational speed) of the TN characteristics is 12 for 12 parallel circuits, the center of the vertical axis would be 6. However, in this state, the load due to wind at high speeds increases, and it is thought that the value will not reach 6. Therefore, even with 12 coil elements, the actual maximum number of rotations that can be switched can be less than 6. It is also effective to reduce the number of switches by selecting and using only the following: Maximum rotation 1 (12V connection pattern) where the intervals between maximum rotations are equalized, Maximum rotation 2 (turning on a total of 10 switches: sw1~sw4, sw6~sw9, sw14, sw23, and turning off the others. This results in 2 series of 6 coil elements), Maximum rotation 3 (turning on sw1, sw2, sw4, sw5, sw7~sw9, sw12, sw15, sw21, sw24, and turning off the others, creating 3 series of 4 coil elements), and Maximum rotation 4 (turning on sw1, sw3, sw4, sw6, sw8, sw9, sw11, sw14, sw16, sw20, sw23, sw25, and turning off the others (4 series of 3 coil elements)). [Explanation of Symbols]

[0061] 10...Motor device, 12...Housing, 12a...Bearing, 14...Rotating shaft, 16...Rotor, 16a...Permanent magnet, 16b...Inner yoke, 16c...Outer yoke, 18...Stator coil, 30...Gear switching operation means, 31...Controller, 32...Shift register, 33...NOR element, 34...NOT element, 35...AND element, 36...AND element, 37...U-phase block, 38...V-phase block, 39...W-phase block, A,B...Long coil elements, C,D...Short coil elements.

Claims

1. Equipped with a permanent magnet, a rotor, and a stator coil, The stator coil consists of multiple phases, and each phase is constructed using two short coil elements and two long coil elements that are twice the length of the short coil elements, thereby using the equivalent of six short coil elements. The configuration includes placing contact points between each coil element. The first pattern involves connecting all the coil elements used in series, A second pattern involves connecting two of the aforementioned short coil elements in series to form a coil element equivalent to one long coil, and connecting two of the aforementioned long coil elements in parallel. A rotating electric machine characterized by being able to switch between two sets of coil elements, each consisting of a short coil element and a long coil element connected in series, connected in parallel, or a third pattern in which two long coil elements connected in parallel and two short coil elements connected in parallel are connected in series.

2. Equipped with a permanent magnet, a rotor, and a stator coil, The stator coil consists of multiple phases, and each phase uses N short coil elements (where N is an integer of 2 or more) and N long coil elements that are N times the length of the short coil elements, with contacts placed between each coil element. The first pattern involves connecting all coil elements in series, A second pattern involves connecting N short coil elements in series to form a single coil element, and then connecting all N long coil elements in parallel. A rotating electric machine characterized by being able to switch between a configuration in which the short coil element and the long coil element are connected in series, and N such configurations are connected in parallel, or a third configuration in which a coil element made of N long coil elements connected in parallel and a coil element made of N short coil elements connected in parallel are connected in series.

3. A rotating electric machine comprising a permanent magnet, a rotor, and a stator coil, The stator coil consists of multiple phases, and each phase uses N short coil elements (where N is an integer of 2 or more) and N long coil elements that are N times the length of the short coil elements, with contacts arranged between each coil element. A rotating electric machine characterized by switching the connections of the constituent coil elements to make the T-N characteristics of the rotor different for each switching pattern, and selecting the switching pattern such that the interval between the maximum rotational speeds of any two of the switching patterns (including the interval from zero rotational speed in the case of the maximum rotational speed when all coil elements are in series) is substantially equal.

4. The rotating electric machine according to claim 1, characterized in that the long coil element is composed of two short coil elements connected in series without contacts.

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