JP7846882B2 - Rotating electrical machinery - Google Patents

Description

This invention relates to a rotating electrical machine, and more particularly to a rotating electrical machine suitable for efficient operation.

As a technique for changing the characteristics of a motor as a rotating electrical machine, as disclosed in Patent Documents 1 and 2, switching the connection configuration of the internal windings has been proposed. For example, Patent Document 1 relates to a motor for a machine tool, in which a coil composed of three phases is used as the stator, and each phase is composed of multiple coil elements with different winding counts. Furthermore, the configuration is such that the total number of windings of the coil decreases during high-speed rotation, and increases during low-speed rotation, by selectively connecting one to multiple coil elements in series.

Furthermore, Patent Document 2 discloses technology related to motors mainly for power tools or starter generators for automobiles. The motor disclosed in Patent Document 2, like the motor disclosed in Patent Document 1, uses a stator composed of coils with three phases. Each phase is composed of multiple coil elements, and the motor is equipped with a switch device that can switch between connecting the multiple coil elements constituting each phase in series or parallel. With this configuration, in series connection, the magnetic field excited by the coils becomes stronger, improving torque, while in parallel connection, the magnetic field weakens, enabling high-speed rotation.

Furthermore, Patent Documents 3 and 4 describe how, in a coreless motor having multiple phases, the characteristics of the motor can be made different by specifying the connection method of each phase as either series or parallel. In addition, Patent Document 5 describes how, in a motor with fixed coils, a circuit is used when switching the connection method of the coil elements constituting the three-phase coils between series and parallel.

Patent No. 3596711 Special Publication No. 2010-537621 Japanese Patent Publication No. 2014-121102 Japanese Patent Publication No. 2019-54628 Japanese Patent Publication No. 2011-229221

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

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 suffers from high self-inductance due to the influence of the iron core, raising concerns about a time lag between switching and characteristic changes.

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 carries the risk of 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.

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.

In the following explanation, a coil element is 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. This reduces the number of coil element indirection points compared to using six short coil elements, and the machine is characterized by being able to switch between the following connection patterns: a first pattern in which all coil elements 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.

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; rather, they 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).

The most suitable rotating electric machine to which this invention applies is a coreless motor, because, unlike a cored motor, it lacks an iron core, resulting in lower inductance. In this sense, even among cored motors, a slotless type motor without iron core teeth is also suitable.

Furthermore, while 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; multiple elements may be provided.

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).

Ideally, a switching pattern corresponding to the total number of coil elements could be provided. However, in this invention, some possible patterns are intentionally left unused (because the number of coil contacts is reduced, resulting in unused patterns). Reducing the number of contacts lowers the risk of defects and failures, and also leads to cost reduction. From the perspective of the T (torque)-N (rotational speed) characteristics, it is comfortable and convenient for the driver if the rotational speed switches with a nearly small interval (difference). The inventors believed 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 coil length 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 considered the maximum rotational speed for normal use.

Furthermore, in a rotating electric machine having the above-described characteristics, the stator coil should preferably have a cylindrical structure. This configuration allows for the creation of air gaps within the motor's internal space. Therefore, the internal space of the motor can be effectively utilized. Moreover, its deformation resistance prevents deformation of the stator coil due to the counter-torque generated when the rotor rotates, even when the motor capacity is increased.

Furthermore, in a rotating electrical machine having the above-described characteristics, the stator coil is preferably composed of three phases: U, V, and W. Having these characteristics avoids complexity in the number of coils and circuits, making it possible to reduce manufacturing costs during mass production.

Furthermore, in a rotating electrical machine having the characteristics described above, the coil should preferably be constructed using Litz wire. This characteristic allows for sufficient strength to maintain the shape of the stator coil, and eliminates the need to use iron or copper plates in the stator coil, thereby reducing its self-inductance.

The rotating electrical machinery possessing the above characteristics can handle capacities unmatched by conventional technology, maintain a predetermined torque even at high rotational speeds, and improve responsiveness during characteristic switching. Furthermore, reducing the number of coil element joints reduces the risk of defects and failures, contributing to cost reduction.

This figure illustrates the relationship between the circuit configuration pattern of a stator coil in a rotating electric machine according to an embodiment of the present invention and its T-N characteristics. This figure illustrates the relationship between the circuit configuration pattern of a stator coil in a rotating electric machine, which is an adaptation of the embodiment shown in Figure 1, and its T-N characteristics. This is an example of a circuit diagram showing the connection of the coil and switch in the embodiment shown in Figure 1. The connection circuit diagram of the coil and switch in the embodiment shown in Figure 1 is a different example from that shown in Figure 3. Figure 3 shows the circuit diagram for the proposed design, with all three phases (U, V, and W) displayed together. This is a side cross-sectional view illustrating a structural example of the rotating electric machine of the present invention. This is a system diagram for the operation of a rotating electric machine, including a coil switching device applicable to each embodiment of the present invention. This figure shows an example configuration of a control unit that outputs a command signal to a circuit section using a switching element, which can be applied to each embodiment of the present invention. This figure illustrates an example of a stator coil connection pattern according to another embodiment of the present invention. This figure illustrates an example of a stator coil connection pattern according to yet another embodiment of the present invention. This figure shows a coil element pattern according to another embodiment of the present invention.

The embodiments of the rotating electric machine of the present invention will be described in detail below with reference to the drawings. In the embodiments described below, a motor will be used as an example of a rotating electric machine.

[Basic configuration]
First, with reference to Figure 6, the basic configuration of the motor device 10 according to this embodiment will be described. 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.

The stator coil 18 is configured to form a cylindrical shape using a group of coil elements divided into multiple phases (in this embodiment, three phases: U-phase, V-phase, and W-phase). Each of the U-phase, V-phase, and W-phase constituting the stator coil 18 consists 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.

Furthermore, the rotor 16 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 located on the outer circumference side of the stator coil 18 (radially outward side with the cylindrical center as the base point), and the inner yoke 16b is located on the inner circumference side of the stator coil 18. In the motor device 10 according to this embodiment, the permanent magnet 16a is configured to be located inside the outer yoke 16c and on the surface opposite the stator coil 18.

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. Furthermore, because the stator coil 18 does not have an iron core, its self-inductance can be kept low.

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

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

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

The stator coil 18 according to this embodiment is characterized by the combined use of short 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 element" and "long coil element" are used for convenience in the following explanation, but essentially, in this application, the coils normally used are called short coil elements, and coil elements 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.

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 (twice 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, three patterns are possible: one where A, B, C, and D are all in series, resulting in 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, resulting in 3V and 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, resulting in 2V and 0.67Ω. If the long coil elements A and B were short coil elements, a pattern where all six coil elements are in parallel could be created, but in this invention, since long and short coil elements are used in combination, a pattern where all six coil elements are in parallel cannot be created.

The T-N characteristic diagram in Figure 1 shows the characteristics of these three patterns. Since a motor is configured for each pattern, this invention incorporates three motor patterns within a single motor device, transforming into three different motors by switching the connection of the coil elements. In Figure 1, the vertical axis represents rotational speed, and the horizontal axis represents torque. The scales on both 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 replaced with speed. The same applies to the horizontal axis).

In the first pattern, when two long and two short coil elements are connected in series, the maximum rotational speed of the motor constructed using this 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 using this 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 and 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 using this third pattern is 6V/2V = 3, as shown by the line connecting scale 3 and torque scale 3 on Figure 1. By creating these three patterns, the interval between the maximum rotational speeds of the motors in the first and second patterns becomes substantially equal to the interval between the maximum rotational speeds of the motors in the second and third patterns.

Furthermore, when the motor device 10 is configured using this pattern switching, there is no motor that corresponds to the six parallel configuration expected with the original six coil elements (six short coil elements), i.e., a motor with the highest rotational speed at the uppermost scale position on the vertical axis. However, the interval (difference) between the highest rotational speed of the six-parallel equivalent motor and the highest rotational speed of the third pattern motor is significantly larger than the interval between the highest 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. Therefore, in this embodiment, by eliminating the switching to the six-parallel equivalent motor, the shock to the operator and the device caused by the gear function switching is eliminated, enabling smooth device operation.

As shown on the vertical axis of the characteristic diagram in Figure 1, the motors to be used are selected so that the interval between their maximum rotational speeds (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). Motors that do not meet this condition may be left unused. For example, if it is less than 0.5 times, the switching becomes too fine and the switching control becomes complicated, but in practical terms, 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.

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 outset. However, in the example in Figure 2, instead of using a material called a long coil element, all components are made from 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 this is used as the equivalent of the long coil element in the first embodiment. Furthermore, the 6-parallel equivalent (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). Therefore, the resulting configuration is similar to the first embodiment, and the same effects can be obtained (the following explanation uses an example common to both Figure 1 and Figure 2).

The circuit diagrams for the switches and coil elements in this embodiment are shown in Figures 3 and 4 for each phase. 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 Figure 4, 11 switches are required for each phase, further reducing the number of switches compared to Figure 3. If six coil elements of the same length (6-coil elements) are used, 15 switches are required. On the other hand, if four coil elements of the same length (4-coil elements) are used, 9 switches are required, but this example requires fewer switches than the original 6-coil element configuration.

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 long and short coil elements is not limited, but when using them in combination, connection measures should be taken to prevent the generation of circulating current.

[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, because the number of contacts is small, it reduces the causes of defects and failures and contributes to cost reduction.

Generally, there is a trade-off between increasing motor torque and increasing motor maximum rotational speed. Increasing torque reduces maximum rotational speed, and increasing maximum rotational speed reduces maximum torque. Therefore, conventional methods have focused on increasing rotational speed through higher power voltage and torque through higher power current. However, these control methods have safety concerns and technical limitations. The inventors have therefore solved these conventional problems by electrically and automatically switching between motors with different characteristics. By employing this method, while maintaining a single motor unit, it is possible to enable multiple-stage circuit switching (switching of coil element connections using a coil switching device), such as Low gear, 2nd gear, and Top gear, thereby achieving an effect similar to automatically switching between multiple motors with different characteristics.

Here, the Low gear offers high torque and low rotational speed, allowing high torque to be generated with a small current. While increasing rotational speed in the Low gear requires high voltage, this is not necessary in the Low gear stage because it operates at low rotational speeds. Furthermore, the 2nd gear offers medium torque and medium rotational speed, while the Top gear offers low torque and high rotational speed (high-speed rotation possible with low voltage). While obtaining high torque in the Top gear requires a large current, this is not necessary in the Top gear stage because it operates at low torque.

By adding a coil element switching function to the motor in this way, a single motor unit can handle various driving scenarios. Therefore, high voltage and high current output of the driver become unnecessary, reducing overload on the motor unit and suppressing rapid temperature increases.

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 in each phase, thereby switching between a series Lo state and multiple parallel (e.g., second, third) or a combination of series and parallel connections. In other words, by selecting the position and number of coil elements in each phase, the connection type can be switched between a series configuration and multiple parallel configurations. Therefore, when applied to electric vehicles such as bicycles, motorcycles, mobility scooters, wheelchairs, and automobiles, it becomes possible to achieve a function equivalent to multiple gear switching (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 cored motors.

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 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. Vehicle speed detection may be performed using sensors (not shown), and various conventional (known) methods can be used. The timing of the coil element connection switching is performed by a coil element connection pattern switching device 80 (see Figure 7), which has various speed detection timing settings.

Figure 7 shows the system diagram illustrating the connection relationships between the controller 31, driver 40, coil element connection pattern switching device 80, and motor unit 10. First, the controller 31 determines the torque output from the motor unit 10 based on throttle information and speed information. Throttle information represents the throttle opening; for example, it is 0% when the throttle is closed and 100% when the throttle is fully open. 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.

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.

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.

The controller 31 calculates the current value required to produce the predetermined torque for each gear and instructs the driver 40 accordingly. The current command to the driver 40 is executed simultaneously with the gear switching instruction. Therefore, the output torque fluctuation during gear switching is very small, resulting in smooth switching. In other words, a current command that maintains torque before and after switching is issued simultaneously with the switching, resulting in smooth switching. For example, considering a system where the torque constant is 0.4 Nm/A in first gear and 0.2 Nm/A in second gear, if the torque to be output in first 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 second gear, the controller 31 changes the current command given to the driver 40 from 2.5 A to 5 A simultaneously with the switching instruction. This maintains the torque output from the motor device 10 at 1 Nm before and after the switch, achieving smooth switching.

Incidentally, the circuit shown in the above embodiment can be built into the motor device 10. When the circuit is housed within 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 electromachine even without a rotating shaft 14. This is possible because the rotating shaft 14 and the rotor 16 are not connected by a core. For example, this can be achieved by directly connecting the rotating shaft of an input/output device to the rotor 16. In such a configuration, the inside of the motor device 10 becomes a hollow structure, allowing for more effective utilization of the internal space.

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 applying the motor device 10 according to the present invention to the propulsion power of an electric vehicle, it is also possible to detect the vehicle speed (vehicle speed) of the electric vehicle to which the motor device is applied and perform the switching of the coil element connection pattern switching device based on the detected vehicle speed value. Regarding the detection of vehicle speed, various conventional (known) methods can be used, such as using sensors not shown in the figures.

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.

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 constituting a block. Note that the example shown in Figure 8 is an example of a circuit diagram for a block constituting the U phase, but the blocks constituting the V phase and W phase have similar configurations. For example, Lu1h becomes Lv1h in the V phase and Lw1h in the W phase, and Lu2h becomes Lv2h and Lw2h. Also, Lu1l becomes Lv1l and Lw1l, and Vu becomes Vv and Vw, respectively.

In the above embodiment, the number of coil elements and circuit sections is limited, but the number of coils and circuits can be increased or decreased to increase the number of combinations when connecting coils in series and parallel. Furthermore, in addition to increasing the number of combinations of coil element connection configurations, the appropriate rotational speed and torque can be selected according to the application, and the combinations of coil connection configurations can be limited accordingly. For example, when applying to applications where a rotational speed is desired to exceed the initial torque of power tools, the coil combination that enables characteristic operation in the high-speed range can be selected and switched.

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. However, the switch may also be provided by a semiconductor chip to achieve a similar function.

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 lack iron core teeth, so there is no iron loss, and the inductance is small, similar to coreless motors.

Figure 9 illustrates examples 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. Patterns (D), (I), (M), and (Q) each consist of four long coil elements and one short coil element. In each pattern, the long and short coil elements are connected as shown in the diagram. Switches are omitted from the diagrams for each pattern.

The coil element connection pattern of the present invention is not limited to the pattern shown in this figure, but the combined use of 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) is essential, and these long coil elements are not disassembled for use. This reduces the number of contacts and switches, yet allows for a gear switching width equivalent to the total number of short coil elements (i.e., 10 coil elements in the example of Figure 9) in terms of switching control.

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 contact points, 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 examples using N long coil elements and N short coil elements are 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 pattern shown in Figure 10 can be switched using a combination of three short coil elements and three long coil elements.

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 have no contacts (switches) between them; they are directly connected by solder or other means, or formed from the outset at twice the length of the short coil element.

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 different 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. The number of contacts can be reduced by using coil elements with a larger number of turns (equivalent to long coil elements).

Furthermore, if the assumed maximum value of the vertical axis (corresponding to rotational speed) of the T-N characteristic is 12 for 12 parallel connections, the center of the vertical axis will be 6. However, in this state, the load due to wind at high speeds increases, and it is thought that it will not reach 6. Therefore, even if the number of coil elements is 12, the actual maximum number of rotational speeds that can be switched on can be less than 6, resulting in an even spacing between the maximum rotational speeds: Maximum rotational speed 1 (12V connection pattern), Maximum rotational speed 2 (10 switches in total: sw1-sw4, sw6-sw9, sw14, sw23 are turned ON, and the others are turned OFF. This results in two series of 6 coil elements), Maximum rotational speed 3 (sw1, sw2, sw4, sw5, sw It is also effective to reduce the number of switches by selecting and using only the following: 7-sw9, sw12, sw15, sw21, sw24 ON, and the others OFF to create three series of four-coil elements in series), and a maximum rotation speed of 4 (sw1, sw3, sw4, sw6, sw8, sw9, sw11, sw14, sw16, sw20, sw23, sw25 ON, and the others OFF (four series of three-coil elements in series)).

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 (4)

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. 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. 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. 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.