WO2005018074A1 - Commutator motor and electric power drill - Google Patents

Abstract

A commutator motor in which a field winding (1) wound around a stator (3) is connected with a rotor winding (4) wound around a rotor (6) through a commutator (7), and an AV power supply is connected with the field winding (1) and the rotor winding (4). The brush (8) is pivotable in the circumferential direction of the commutator (7) and the rotor (6) is held in a stop state by imparting a specified contact pressure to the brush (8) such that a frictional for turning the commutator (7) together with the brush (8) located at a base point position when the rotor (6) is stopped is obtained between the brush (8) and the commutator (7). A commutator motor in which the rotor can be sustained reliably in a stop state through a simple and inexpensive arrangement is thereby obtained.

Description

Commutator motors and electric drills

 According to the present invention, a field winding wound on a stator is connected to a rotor winding wound on a rotor via a brush and a commutator, and the field winding and the rotor are connected to each other. The present invention relates to a commutator motor in which an AC zero source is connected to a winding, and more particularly to a configuration for holding a rotor of a motor in a stopped state. The present invention also relates to an AC motor (commutator motor) having a commutator and an electric drill, and more particularly, to a commutator motor capable of controlling a wide range of torque with a simple structure and an electric drill incorporating the same. About. Further, the present invention connects the field winding wound on the stator to the rotor winding wound on the rotor via a brush and a commutator, and exchanges the current with the field winding and the rotor winding. The present invention relates to a commutator motor connected to a power supply.

Background art

 In motors, a stop state maintaining function such as a perkinda brake is required to keep the rotor of the motor stopped when external force is applied. Conventionally, a lock mechanism for mechanically restraining the output shaft of a motor is added to keep the rotor of the motor stopped (for example, Patent Document 1: Japanese Patent Application Laid-Open No. 7-277715). Alternatively, there is a type in which a reverse torque is generated based on the output of the position sensor to electrically hold the rotor in a stopped state.

For example, in the case of a servo motor, it is necessary to detect the position of the rotor and feed back the detected position to change the voltage and current of the field winding, or to switch the polarity of the power supply. Therefore, a device that can externally control a large amount of power using a resistor or PWM is required. Also, in order to maintain the stop state without using the position sensor, a large control current (electric power) is always required to maintain the stop position. It becomes. On the other hand, in the case of an induction motor, there is a problem that even if an attempt is made to obtain the same function of maintaining a stopped state by fixing the rotating magnetic field, there is slippage, and a positional shift occurs over time. Furthermore, in the case of stepping motors, due to their characteristics, there is a problem that there is no large-capacity motor that cannot be repaired even if the position shifts after stopping.

 As described above, in the conventional motor, in order to maintain the stopped state of the rotor, if the lock mechanism is a mechanical lock, the force or the position of the rotor is detected, and the detected position is fed-packed. A servo control circuit that changes the voltage and current of the field winding is required, and the device configuration is complicated, large-scale, expensive, and power consumption increases. In addition, when the stop state is maintained by using the servo control circuit, a configuration that can control high power is required, and there is a problem that it is difficult to easily deal with a large machine with high power.

 In general, when speed control is performed in an electric motor, for example, a speed control method using a resistance change by a variable resistor, a speed control by changing a voltage by a servo control, a slidac, a conduction angle control, or the like. Various methods have been adopted, such as a method of performing speed control by changing the frequency using an inverter, such as VVVF, and a method of controlling speed by switching the number of poles. '

 However, according to the above-described conventional techniques, an external control device is required to control the speed of the motor regardless of which method is adopted, which complicates the device configuration and increases costs. If the resistance and voltage values cannot be changed over a wide range, only a few steps of speed change are required, which limits the speed control range. In addition, when controlling the rotation speed by limiting the current using a resistor or a triac, the torque becomes extremely weak and the rotation becomes unstable at low currents. '

Further, in the above-described conventional technique, when the rotation direction of the rotor is switched, the polarity of the stator winding is switched or the phase of the rotating magnetic field is reversed, so that the device configuration becomes complicated. There were also problems. The electric, on its properties by machine, the rotational torque could not be widely varied _ά Further, in the control using the Toraiatsuku, since the unstable portion is generated in the vicinity of the zero crossing of the waveform smoothly at the time of low-speed rotation Driving was difficult.

 Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2000-270952) discloses a method of performing speed control by moving a brush. That is, in this Patent Document 2, the armature magnetic pole is formed at an angle of 90 degrees with respect to the magnetic pole of the field, that is, at a position where the phase is shifted 90 degrees with respect to the magnetic pole of the field. By controlling the brush position from this position, the armature speed control and rotation direction switching control are performed.

 However, in Patent Document 2, when the power is turned on, the brush is arranged at a position where the armature magnetic pole is formed at a position forming an angle of 90 degrees with respect to the field magnetic pole. However, the reactance of the field winding and the armature winding becomes a small value, a large inrush current flows, and the field winding and the armature winding are burned, and the commutator and the brush are damaged. . 'To solve this, it is necessary to insert a starting resistor or to control the phase of the power supply frequency, which makes the device configuration complicated and expensive. The present invention has been made in view of the above problems, and has as its object to provide a commutator motor that can maintain a reliable stopped state of a rotor with a simple and inexpensive configuration.

 In addition, the present invention can change the rotation torque over a wide range with a simple structure, can provide a wide speed control range without requiring an external device in the speed control, and can easily reverse the rotation direction. It is an object of the present invention to obtain a commutator motor and an electric drinore incorporating the same.

 In addition, the present invention provides a commutator motor that has a simple and inexpensive configuration, suppresses inrush current when the power is turned on, can easily cope with a large machine with high power, and consumes less current. The purpose is to do.

Disclosure of the invention In order to achieve the above object, a commutator motor according to the present invention connects a field winding wound on a stator to a rotor winding wound on a rotor via a brush and a commutator. In a commutator motor in which an AC power source is connected to the field winding and the rotor winding, the brush is configured to be rotatable in the circumferential direction of the commutator, and the brush positioned at the base position is connected to the commutator. A brush urging means is provided for applying a predetermined contact pressure to the brush so that different frictional force is obtained between the brush and the commutator, and the rotor is stopped by the brush urging means. It is characterized by holding.

 According to the present invention, a predetermined contact pressure is applied to the brush by the brush urging means so that the frictional force of the brush rotating with the rotor and the commutator is obtained between the brush and the commutator. . When the rotor at which the brush is located at the base position stops, an external force acts on the rotor to rotate the rotor in the forward direction, so that the brush also rotates from the base position in the forward direction. This movement of the brush generates a reverse torque on the rotor, causing the rotor to rotate back to its original position. When the rotor rotates in reverse, the brush follows the rotor. The same applies to the case where the rotor rotates in the reverse direction due to the external force acting on the rotor. The brush also rotates in the reverse direction with the rotation of the rotor. This movement of the brush generates a torque in the forward direction at noon, and the rotor returns to its original position with the brush. As described above, according to the present invention, the rotor is kept stopped by applying a predetermined contact pressure to the brush so that the frictional force of the brush rotating with the commutator is obtained between the brush and the commutator. This eliminates the need for a mechanical lock mechanism or a servo control circuit, and allows a simple and inexpensive device configuration. In addition, since a servo mechanism is not required, it can easily handle large machines with high power. Furthermore, since the brush is basically located near the 0 degree position, current consumption can be reduced.

The commutator motor of the next invention comprises a stator winding wound on a stator core, a rotor winding wound on a rotor core, and a plurality of commutator pieces. In a commutator motor having a brush contacting the connected commutator, and an AC power supply connected to each of the stator winding and the rotor winding, the stator winding and the rotor winding are directly wound or wound. A configuration in which each commutator piece of the commutator is given a skew in the axial direction by connecting windings, and the brush and the commutator are relatively movable along the axial direction of the commutator. Features.

 According to the present invention, since the brush and the commutator are configured to be relatively movable along the axial direction of the commutator, a wide range of torque control can be achieved simply by moving the brush relative to the commutator in the axial direction. Eventually, speed control becomes possible, and there is no need to install external devices such as conventional inverter / servo control, and the structure is simple and inexpensive.In addition, there is no operation such as switching of the rotating direction and the switch between the brush and commutator. It can be easily changed only by relative movement in the direction. Also, unlike the control using triac, there is no instability near the cross-section of the waveform, and smooth operation is possible even at low speed rotation.

 In the commutator motor according to the next invention, the skew angle of each commutator piece is either brush or commutator within the relative axial movement range of the brush and the commutator. The number of commutator segments that can be brought into contact with the brush by moving the brush must be such that the difference in electrical angle of the rotor winding connected to the commutator segment is 90 degrees or more. @@.

 According to the present invention, the skew angle is set to an electrical angle of 90 degrees or more in the relative axial movement range of the brush and the commutator, so that torque control from at least torque 0 to the torque near the maximum can be achieved. Becomes possible.

 The commutator motor according to the next invention is the commutator motor according to the invention described above, wherein a relative axial movement range between the brush and the commutator is ± with respect to the brush position at an electrical angle of approximately 0 degrees of the rotor winding. It should be 90 degrees or more.

 According to the present invention, the relative axial movement range of the brush and the commutator is 90 degrees or more around the brush position, which is approximately 0 degrees in electrical angle of the rotor winding. By the relative axial movement with the commutator, forward, stop, reverse torque or rotation direction control can be continuously performed.

The commutator motor according to the next invention is the above-mentioned invention, wherein The skew of the formed commutator is characterized in that it is twisted clockwise in the circumferential direction of the commutator from one end in the axial direction of the commutator to the other end, and then twisted counterclockwise in the circumferential direction.

 According to the present invention, the relative axial movement of the brush and the commutator in one direction of forward or backward movement, for example, from torque 0 to torque maximum and torque 0, or from torque maximum to torque 0 and torque maximum. It is possible to perform control that continuously changes in condition.

 According to the following electric drill invention, since the commutator motor described in the above invention is incorporated as a power source, torque generation control and blade rotation control in accordance with the drilling process of the electric drill are performed. It is possible to obtain an electric drill with good operability.

 Further, in the commutator motor according to the present invention, the field winding wound on the stator is connected to the rotor winding wound on the rotor via the brush and the commutator, and the field winding and the like. In a commutator motor in which an AC power source is connected to a helical winding, the brush is configured to be rotatable in a circumferential direction of the commutator, and the brush corresponds to an electrical angle of approximately 0 degrees when the AC power source is turned on. A brush holding means for holding the brush so as to be positioned at a base position to be rotated, and after turning on the AC power, controlling a rotating position of the brush to generate forward rotation torque and / or reverse rotation torque on the rotor. And a brush rotation driving means for causing the rotation.

According to this invention, switching of the rotation direction of the rotor and torque control are performed by controlling the rotation position of the brush with respect to the commutator, and the brush corresponds to an electrical angle of approximately 0 degrees when the AC power is turned on. When the power is turned on, the reactances of the field winding and the armature winding are maximized, so that the inrush current can be suppressed to a very small value. As a result, the equipment configuration can be made simple and inexpensive, and it is possible to easily cope with large machines with high power. Furthermore, since the brush is basically located near the 0 degree position, the current consumption is small. In the electric motor according to the present invention, the brush is located at the base position corresponding to the electrical angle of approximately 0 degrees. When the power of the motor is turned on, the brush position can be gradually advanced (turned) in the positive or negative direction from this base position in the direction in which the electrical angle increases. It is possible to supply a necessary and sufficient current according to the condition. Therefore, not only when the power is turned on but also when starting the rotation, a large current does not flow and there is no unnecessary power consumption. At this time, sufficient torque is generated because the current of the motor is not limited by the external device.

Brief Description of Drawings

FIG. 1 is a conceptual exploded configuration diagram showing a first embodiment of a commutator motor according to the present invention, and FIG. 2 is a principle of brush rotation which is a premise of the first embodiment of the present invention. Fig. 3 is a conceptual diagram showing the state of the rotor at each angular position of the brush, and Fig. 4 is a conceptual diagram illustrating the configuration of the rotor for stopping and holding. FIG. 5 is a memorial view illustrating a configuration for holding and stopping the rotor, and FIG. 6 is a diagram illustrating traveling, braking, and parking brakes of a vehicle driven by the electric motor according to the first embodiment. FIG. 7 is a diagram showing a key mechanism, FIG. 7 is a simplified configuration diagram of Embodiment 2 of the present invention, and FIG. 8 is an explanatory diagram of a commutator having a skew according to Embodiment 2 of the present invention. FIG. 9 is a developed view of a commutator and a rotor winding according to Embodiment 2 of the present invention. FIG. 1 is a diagram illustrating the principle of a second embodiment of the present invention. FIG. 11 is a diagram illustrating the state of the second embodiment of the present invention. FIG. FIG. 13 is a torque characteristic diagram of FIG. 2, FIG. 13 is a configuration diagram of an electric drill which is a specific example of the present invention, and FIG. 14 is a simplified configuration of a specific example of the second embodiment of the present invention. FIG. 15 is a simplified configuration diagram of another specific example of the second embodiment of the present invention, and FIG. 16 is a configuration diagram showing a modification of the ^second embodiment of the present invention. FIG. 17 is a conceptual exploded view showing an example of the commutator motor according to the third embodiment of the present invention. FIG. 18 is a diagram showing the principle of rotor rotation by brush rotation. Fig. 19 is a diagram when the brush is at 0 electrical angle, when the electrical angle is +90 degrees, when the electrical angle is 90 degrees: and when the electrical angle is +120 degrees. It is a diagram for explaining the state of the rotor and the like, FIG. 20 is a diagram showing a mechanism for rotating the brush according to the first embodiment of the third embodiment. FIG. 21 is a diagram illustrating a mechanism for rotating the brush according to the second embodiment of the third embodiment. FIG. 22 is a diagram showing a mechanism for rotating a brush according to a third embodiment of the third embodiment. FIG. 23 is a diagram showing a pressing rod and a pressing rod used in the third embodiment. FIG. 24 is a diagram showing details of a front-rear switching pad, and FIG. 24 is a diagram showing a mechanism for rotating a brush according to a modification of the third embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

 In order to explain the present invention in more detail, this will be described with reference to the accompanying drawings. (Embodiment 1)

 Hereinafter, preferred embodiments of a commutator motor according to the present invention will be described in detail with reference to the drawings.

 FIG. 1 is a conceptual exploded view of an AC commutator motor for explaining Embodiment 1 of the present invention. An AC commutator motor has a structure in which the stator of an induction motor and the rotor of a DC motor are combined. Although it is an AC machine, it has a commutator and a brush. FIG. 1 shows a series motor in which a field winding 1 and a rotor winding 4 are connected in series.

 ′ In FIG. 1, a rotor 6 having a rotor core 5 in which a rotor winding 4 is wound with respect to a stator 3 having a stator core 2 wound with a field winding 1 is rotated. They are arranged freely. The rotor 6 is provided with a commutator 7 and a pair of brushes 8, and the commutator 7 and the pair of brushes 8 are connected to the rotor winding 4. The commutator 7 has a plurality of commutator pieces 71. One end of the field winding 1 is connected to an AC power supply (not shown), and the other end is connected to one brush 8. The other brush 8 is connected to an AC power supply.

Here, in the AC commutator motor shown in FIG. 1, the brush 8 has a structure in which the brush 8 is brought into contact with the commutator ⁷ at a predetermined contact pressure and is rotatable (movable) in the circumferential direction of the commutator 7. ing. That is, the pair of brushes 8 maintain the positional relationship between the brushes. Until the commutator 7 rotates or stops, the commutator 7 can rotate in the circumferential direction.

 The relationship between the rotational position of the brush 8 and the generated torque will be described with reference to FIG. In Fig. 2, the field poles of stator core 2 are N and S poles. The rotor core 5 is provided with four rotor windings 4 having a two-layer winding coil side 4 1, and four commutator strips 7 1 from the rotor winding 4 via lead wires 42. Is connected. FIG. 2 (a) shows a state in which the brush 8 is in contact with the left and right commutator pieces a and a '(referred to as a 90-degree brush position) in FIG. 2 (b), and FIG. This shows the state where the brush 8 is in contact with the upper and lower commutator pieces b, b, and (called the 0-degree brush position). Therefore, the brush positions in FIGS. 2 (a) and 2 (b) have a positional relationship different from each other by 90 degrees, and the electric field changes by 90 degrees in the two field poles.

 Here, the brush position having an electrical angle of 0 degrees corresponds to the base position in the claims, and the mutual relationship between the magnetic flux created by the field winding 1 and the magnetic flux created by the rotor winding 4. The angles are substantially parallel, and the magnetic pole generated by the magnetic flux created by the force field winding 1 and the magnetic pole generated by the magnetic flux created by the rotor winding 4 have an attractive relationship. State. The brush position at an electrical angle of 90 degrees means that the mutual angle between the magnetic flux created by the field winding 1 and the magnetic flux created by the rotor winding, 锒 4, is substantially perpendicular.

 In such a configuration, the armature current (rotor current) flows between the rotor windings 4 connected by the brushes 8, and as a result, the armature current on the coil side 4 1 A torque is generated by the armature current and the magnetic flux generated by the field poles, which are determined by the two types of symbols indicating the direction of the arrow, namely, the symbol from the front to the back of the drawing and the symbol from the back to the front of the drawing. .

At the 90-degree brush position shown in Fig. 2 (a), current flows in the same direction on the ^two coil sides 41 forming the left and right two layers, and the two coils forming the upper and lower layers. Currents in the opposite directions flow through the common sides 41 of the battery. Therefore, in this case, the current flowing through the left and right coin sides 41 immediately before the magnetic pole of the field magnetic flux causes the rotor 6 to have an arrow. As shown by K, a counterclockwise torque is generated.

 On the other hand, at the 0-degree brush position shown in Fig. 2 (b), current flows in opposite directions on the two coil sides 41 forming the left and right two layers, and the two coil layers forming the upper and lower layers. A current flows in the same direction on each of the coil sides 41. Therefore, in this case, the torque generated by the field magnetic flux and the current flowing through the left and right coil sides 41 immediately adjacent to the magnetic pole cancel each other out, and no rotation occurs.

 Thus, at the 90-degree brush position shown in FIG. 2 (a), a rotational force is generated, and at the 0-degree brush position shown in FIG. 2 (b), no rotational force is generated. When the brush 8 is located between the 0-degree position and the 90-degree position, the rotational force increases as the brush 8 approaches the 90-degree position, and the rotational force increases as the brush 8 approaches the 0-degree position. Becomes closer to 0. Further, in practice, the maximum torque is generated in the rotor 6 when the brush position is set to an angle position of 120 degrees to 150 degrees which is 90 degrees or more. The position at which the maximum torque is obtained at .90 degrees depends on the inductance of the field winding 1 and the like. ',

 Although not shown in FIG. 2, the brush 8 is moved from the 0-degree state in FIG. 2 (b) in a counterclockwise direction opposite to that in FIG. When it is positioned at, a rotational force in the clockwise direction opposite to the arrow K is generated in the rotor 6.

 As described above, by changing the rotation position of the brush 8, the rotor can be controlled to any of the state without torque, the normal rotation state, and the reverse rotation state. That is, at the brush ^: 0 degree, no rotating force is generated in the rotor 6 and the brush is rotated from the 0 degree position to the plus 90 degrees, and further to the right as the brush is rotated to 120 degrees or 150 degrees. The torque in the reverse direction increases, and the torque in the reverse direction increases as the brush is turned from the 0-degree position to 190, or even to 120 or 150 degrees.

Next, the cause of the generation of the maximum torque when the brush is positioned at a predetermined angle of 90 degrees or more (for example, 150 degrees) will be described with reference to FIG. Fig. 3 (a) to Fig. 3 (d) show the state of the rotor when the brush is positioned at various angular positions (0 degree, 90 degrees, 120 degrees, and 190 degrees). Things. 0

11

 In an electric motor, as is well known, the 90-degree electrical angle of the brush is an electrical angle that generates the maximum rotational torque (hereinafter simply referred to as torque) for efficiency. However, when the electrical angle of the brush is advanced beyond 90 degrees, the torque is further increased and the rotation speed is increased as compared with the case where the electrical angle is 90 degrees. The cause is as follows.

 First cause;

 To advance the electrical angle beyond 90 °, as shown in Fig. 3 (c), approaching magnetic poles of the same polarity, such as S pole vs. S pole or Ν pole vs. Ν pole As a result, the reactance of the coil is greatly reduced. In other words, when the electrical angle of the brush is advanced beyond '90 °, the reactance of the coil decreases in relation to the electrical angle (extremely when the electrical angle is 180 °), and the current flowing through the coil increases. I do. Therefore, advancing the brush beyond the electrical angle of 90 ° is not possible if the theoretical torque efficiency is reduced by selecting an electrical angle other than 90 °, but the coil current increases. However, the torque itself increases and the rotation speed increases.

 The second cause;

 The reactance of the rotor coil, which is not apparent in the low-speed rotation range of the motor, cannot be ignored in the high-speed rotation range, and the increase in the reactance delays the current and delays the effective effective magnetic flux. Therefore, even though the brush is supplying current to the rotor coil at the electrical angle of 90 °, which is theoretically the highest in efficiency, the generated magnetic flux is delayed, and the effective effective magnetic flux that contributes to the torque is 90 electrical degrees. This is equivalent to the magnetic flux generated when power is supplied to the rotor coil in a state of less than. As a result, the torque decreases and the rotation does not increase.

 In order to solve this, power is supplied with an electrical angle exceeding 90 °. As a result, the effective effective magnetic flux that is generated with a delay is equivalent to that obtained when the rotor coil is supplied with an electric angle with good torque efficiency, and a decrease in torque efficiency can be prevented. Therefore, the torque increases and the rotation speed increases.

As described above, in the second cause, power can be supplied by advancing the electrical angle and canceling out the delay of magnetic flux from another aspect. This is because the power supply can be continued to the rotating commutator piece for a certain period of time by ensuring that the width of the power supply to a certain extent. Therefore, power is supplied to the rotor coil by the advanced electrical angle, and the time when the magnetic flux generated with a delay grows to the effective effective magnetic flux can be secured.

 In an actual experiment, the electrical angle was 90. The rotation speed increased in proportion to the electrical angle, and increased to around 150 °. The cause of the increase in rotation when the electrical angle is advanced by 90 ° 'is that the first factor contributes greatly, and even if the torque efficiency is sacrificed, the reactance of the coil by advancing the electrical angle is greatly increased. This is because extremely large torque is generated due to the large increase in coil current accompanying the decrease.

 Next, a configuration for stopping and holding the rotor, which is a main part of the present invention, for example, a configuration for a perkinda brake of an electric motor vehicle will be described with reference to FIGS. 4 and 5. FIG.

 As shown in FIG. 4, the brush 8 (only one brush is shown) is provided with a plurality of (in this case, eight) commutator pieces 71 by a pressing spring 10 as a brush urging means. With a suitable frictional resistance (contact pressure). This frictional resistance is such that when the commutator 7 rotates, the brush 8 can rotate together with the commutator 7. However, the brush is free from any restrictions on the circumferential movement of the commutator 7 within the movable range between the stoppers 12a and 12b. The stoppers 12a and 12b allow the brush 8 to move freely within a range of, for example, 150 to 115 degrees, and the positions of the stoppers 12a and 12b are variable. be able to.

The brush position shown in black in FIG. 4 corresponds to the 0-degree position shown in FIG. ² (b), and it is assumed that the rotor 6, that is, the commutator 7 is stopped in this state. When the brush 8 is rotated in the direction indicated by the broken line by rotating the brush 8 by an arbitrary angle 0 1 in the direction of the arrow E 1, the rotor 6, that is, the commutator 7, is rotated in the forward direction indicated by the arrow D 1. Torque occurs. Similarly, when the brush ⁸ is rotated by an arbitrary angle に^{2 in the} direction of the arrow E2 and the brush 8 is positioned at the position indicated by the one-dot chain line, the rotor 6 or the commutator Ί 04 005480

13

 Generates a torque in the reverse direction indicated by arrow D2.

 Since the brush 8 is in contact with the commutator 7 with an appropriate frictional resistance (contact pressure) by the pressing spring 10, if an external force acts to rotate the rotor 6 and thus the commutator 7, the brush 8 becomes a commutator. Take along with 7.

 For example, when the commutator 7 is rotated by the external force by the angle 0 2 in the normal rotation direction indicated by the arrow D 1, the brush 8 is also rotated by the angle Θ 2 to the position indicated by the alternate long and short dash line. When the brush 8 is located at the position indicated by the one-dot chain line, as described above, a torque in the reverse direction indicated by the arrow D2 is generated in the rotor 6, that is, the commutator 7. Due to the torque in the reverse direction, the commutator 7 rotates by the angle 0 2 to the original position. The brush 8 returns to the original 0 degree position with the rotation of the commutator 7.

 On the other hand, when the commutator 7 is rotated by an external force by the angle 01 in the reverse direction shown by the arrow D2, the brush 8 is also rotated by the angle 81 to the position shown by the broken line. When the brush 8 is located at the position shown by the broken line, as described above, the rotor 6, that is, the commutator 7, generates a torque in the normal rotation direction shown by the arrow D 1. The commutator 7 rotates by the angle 01 to the original position by the torque in the forward rotation direction. The brush 8 returns to the original position with the rotation of the commutator 7. The above is the principle of the configuration for holding and stopping the rotor. Next, the above-described configuration for holding the stop will be described from another viewpoint with reference to FIG.

 When a current flows through the field winding 1, a magnetic flux is generated in the stator 3. Similarly, when a current is passed through the rotor winding 4, an electromagnet is generated in the rotor 6. When the brush position is 0 degrees, the magnetic circuit including the stator 3 and the rotor 6 maintains a stable suction state as shown in FIG. 5 (a). At this time, the current value for generating torque for the stable attraction state of the magnetic circuit is extremely small.

However, as shown in Fig. 5 (b) and (c), when the brush is in the forward or reverse rotation position, the magnetic circuit opens and the field poles and the electromagnet attract each other. Trying to return to a stable state. At this time, a current corresponding to the magnetic gap of the magnetic circuit flows and a torque corresponding to the current is generated. Next, referring to FIG. 6, a description will be given of traveling, braking and a perkinda brake mechanism of a vehicle driven by the electric motor according to the present invention.

 As shown in FIG. 6, the brush 8 has a frictional resistance capable of rotating with the commutator 7 having a plurality of commutator pieces 71 by the pressing spring 10. Contacting.

 The brush position shown in FIG. 6 corresponds to the 0-degree position shown in FIG. 2 (b), and no torque is generated in the rotor at this brush position. The brush 8 is connected to the accessory pedal 14 and the brake pedal 13 by an appropriate mechanism (not shown). The brush 8 can rotate from a 0-degree brush position to a 90-degree brush position in contact with the horn 12a according to the amount of depression of the accelerator pedal 14. At the 90-degree brush position, the maximum driving torque in this case can be obtained.

Further, the brush 8 can rotate from a 0 degree brush position to a 190 degree brush position in contact with the stopper 12b in accordance with the amount of depression of the brake pedal 13. At the brush position of 90 degrees, the maximum braking torque in this case can be obtained. In FIG. 6, the stoppers 12a and 12b are provided at brush positions of ± 90 °, but as described above, 90 ° to 150 ° at which a substantial maximum torque can be obtained. It is also acceptable to provide the stoppers 12a and 12b at positions between 190 degrees and 150 degrees. When the operation of the accelerator pedal 14 is released while the vehicle is running or when the operation of the brake pedal 13 is released during braking of the vehicle, the brush 8 can return to the 0-degree position. The return springs 11a and lib are provided between the brush 8 and the stopper 12b between the angle 12a. However, when the vehicle is stopped and the parking brake is applied, the function of the return springs 1 la and 1 1 b is released, and the return springs 1 la and 1 1 b do not function as return panels. That is, when the parking brake is operated, the return springs 11a and lib are not functioning, and the brush 8 is moved in the circumferential direction of the commutator 7 with the stoppers 12a and 12b. You can move freely between them. When the parking brake is actuated, the brush 8 is merely in contact with the commutator 7 with the frictional resistance capable of rotating together with the commutator 7 as described above. is there.

 In the configuration shown in FIG. 6, the brush 8 is positioned at the 0-degree angular position (base position) by turning on the electric motor. By operating the accelerator pedal 14, the brush 8 is rotated by an arbitrary angle until the brush 8 comes into contact with the horn, ° 12 a, and this causes the rotor 6 to rotate in the direction of arrow D 1 corresponding to the brush angle. Drive the vehicle by generating driving torque.

 When the accelerator pedal 14 is released while the vehicle is running, the brush 8 is returned to the 0-degree angle position (base position) by the force of the return panel 11a. At this base position, no torque is generated in the rotor 6, and the vehicle is put into the inertial driving state.

 While the vehicle is running, after releasing the accelerator pedal 14, the user operates the brake pedal 13 to rotate the brush 8 by an arbitrary angle from the 0 degree position until it comes into contact with the stopper 12 b. A braking torque is generated in the rotor 6 in the direction of the arrow D2 in accordance with the brush angle to decelerate or stop the vehicle.

 When the parking brake is applied to the vehicle after the vehicle has stopped, as described above, release the function of the return panel 11a and lib and move the brush 8 between the stopper 12a and 12b. The commutator 7 can be freely moved in the circumferential direction. That is, when the parking brake is actuated, the brush 8 is only in contact with the rectifier 7 by the pressing spring 10 with a frictional resistance that allows the brush 8 to rotate.

In this way, if the brush position at the time of stop of the vehicle is set to the 0-degree position and the brush 8 is free with respect to the rotor 6, the external force is applied to rotate the brush 8 as described with reference to FIG. Regardless of whether the rotor 6 rotates in the normal direction or the reverse direction, the brush 8 rotates with the rotor 6 to apply a torque to the rotor 6 in a direction opposite to the rotation direction. . Therefore, the rotor ⁶ converges to the original position together with the brush 8.

For example, when the parking brake is applied on a downhill road, a forward rotation torque in the direction of the arrow D1 is constantly applied to the rotor 6 by an external force, so that the rotor 6 also has an arrow. D Rotate in one direction. With the rotation of the rotor 6, the brush 8 also rotates in the direction of arrow D1. Then, the brush 8 follows up to a brush angle position at which a reverse rotation torque (braking torque) balanced with a normal rotation torque by an external force is generated, and the brush 8 stops at this angle position. In this way, the rotor can be kept stationary on the road.

 As described above, according to the first embodiment, the stopped state of the rotor is maintained only by applying a predetermined contact pressure to the brush 8 so that the brush 8 can obtain a frictional force that rotates with the commutator 7. As a result, a mechanical lock mechanism or servo control circuit is not required, and the device configuration can be made simple and inexpensive. In addition, since there is no need for a service mechanism, it can easily handle large machines with high power. Furthermore, the brush is basically located near the 0 degree position, so that the current consumption is small. In the first embodiment, the description has been given of a 'straw-wound motor'. However, the present invention can also be applied to a shunt-wound motor in which the field winding 1 and the rotor winding 4 are connected in parallel. 'Wear. Further, in the above embodiment, the case where the brush is rotated around the commutator has been described. However, the same motor can be used even if the stator forming the field pole is rotated around the rotor instead of the brush. Drive control is possible.

 (Embodiment 2)

 (Configuration of Commutator Motor of Second Embodiment)

 FIG. 7 is a simplified configuration diagram of a commutator motor according to a second embodiment of the present invention. Here, an exploded view of a series motor having two field poles is used. In the commutator motor according to the second embodiment, a rotor winding 4 is wound on a stator 3 having a stator core 2 on which a stator winding (field winding) 1 is wound. A rotor 6 having a rotor core 5 is rotatably arranged.

The rotor 6 is provided with a commutator 7 connected to the rotor winding wire 4 and rotatable integrally with the rotor 6, and a pair of brushes 8 that come into contact with the commutator 7 at a predetermined pressure. One end of the stator winding 1 is connected to a commercial AC power supply (not shown), and the other end is connected to one brush 8 connected to the commutator ⁷ and the rotor winding 4. 4 005480

17

The other brush 8 is connected to an AC power supply. That is, in FIG. 7, the fixed stator winding 1 and the rotor winding 4 form a straight winding.

 Further, each commutator piece 71 constituting the commutator 7 is arranged with a skew (twist) in the axial direction. In other words, the commutator 7 of the second embodiment has a structure in which commutator pieces 71 having a skew in the axial direction are arranged in a cylindrical shape. '

 On the other hand, the brush 8 is configured to be movable along the axial direction of the commutator 7 while being in contact with the commutator 7. In other words, the brush 8 of the present embodiment is placed at the same position in the circumferential direction so as to be movable in the axial direction. '

 (Relationship between skew angle of commutator piece and axial movement of brush)

Here, the skew angle of the commutator piece 71 with respect to the axial direction of the commutator 7 will be described with reference to FIG. In the second embodiment, when the brush 8 is moved in the axial direction by changing the skew angle of the commutator piece 71, the brush 8 re-contacts (transits) one after another with the plurality of commutator pieces 71. Angle forming _&

 FIGS. 8 (a) and 8 (b) illustrate the state of the skew angle. The front view, the back view, and the development of the four commutator pieces 71 arranged in a cylindrical shape of the rectifier 7 are shown in FIGS. The figure is shown. FIG. 8 shows four commutator pieces 71, A, B, C, and D, which are skewed obliquely upward and to the right.

Also, when the brush 8 moves in the axial direction from the left end to the right end of the commutator 7 as shown by the arrow in FIG. 8 (b), the brush 8 can move onto the ^three commutator pieces 71 in order. It is configured to be able to. Here, when the brush 8 is moved in the axial direction, the brush 8 comes into contact with the commutator pieces 0, A, and B in the order shown in FIG. 8 (b) with the movement of the brush 8 in the axial direction. become.

At this time, since each commutator piece 71 is individually connected to each unit winding of the rotor winding 4, the brush 8 cannot move over the adjacent commutator piece 71, This shows that the connection between the shell 8 and each unit winding changes one after another. That is, by the axial movement of the brush ⁸ on commutator 7 connexion, brush ⁸ will be gradually One Utsurikawa connected one after another to the unit卷線adjacent rotor卷線^4. Fig. 9 shows the N-pole and S-pole field poles, the rotor winding 4 consisting of 16 unit windings (type winding coil), and the skewed commutator piece 7 1 FIG. 4 is an expanded view showing a connection state with the server. Note that the number of field poles, the number of windings of the rotor, and the skew angle are merely examples, and are not particularly limited. In FIG. 9, approximately eight coil sides 4 1 (16 when including one slot and two layers) are arranged corresponding to one field pole N or S. A rotor winding 4 having eight (16 double-layer windings) coil sides 41 is connected to eight commutator pieces 71.

 The skew angle is set so that the brush 8 moves in the axial direction and makes contact with the four commutator pieces 71. The transfer on the four commutator pieces 7 1 by the brush 8 is a transfer of 1/4 of 16 of the commutator pieces 7 1, causing a change of 90 degrees in electrical angle. become. That is, the connection between the commutator piece 71 and the rotor winding 4 connected to the commutator piece 71 is sequentially changed by the axial movement of the brush 8, and the corresponding electrical angle is changed corresponding to the change.

 The configuration of the commutator motor of the second embodiment shown in FIG. 7 is such that the commutator piece 71 has skew in the axial direction as described above, while the brush 8 can move in the axial direction, and the brush The movement of the brush 8 causes the brush 8 to be connected to the adjacent rotor winding 4 one after another, resulting in a change in the electrical angle.

 (Relationship between Electric Angle Variation Due to Brush Movement and Torque Generated by Commutator Motor) Next, the relationship between the electrical angle variation and the generated torque will be described. As described above, the commutator piece 71 with which the brush 8 contacts changes according to the movement of the brush 8. As a result, the brush 8 is connected to the adjacent rotor windings 4 one after another, thereby causing variation in the electrical angle. Moving the brush 8 in the axial direction on the commutator piece 7 1 having skew in this way is equivalent to replacing the brush 8 in the circumferential direction of the commutator with a straight commutator piece without skew. Is equivalent to turning along.

Here, referring to FIG. 10, the brush 8 is replaced along the circumferential direction of the commutator by replacing it with a straight commutator piece having no skew and having a relation equivalent to the second embodiment. The variation of the electrical angle and the generated torque will be described by taking an example of the configuration of rotating. Figure In FIG. 10, the field poles of the stator core 2 are N,. S, and the rotor core 5 is provided with four rotor windings 4 having a two-layer coil side 4 1 ′, An example of a structure in which four commutator pieces 71 are connected from the rotor winding 4 via the lead wire 42 will be described.

 Fig. 10) shows a state in which the brush 8 is in contact with the left and right commutator pieces aa 'in the figure (referred to as a brush position at a 90-degree position), and in Fig. 10 (b), The figure shows a state where the brush is in contact with the upper and lower commutator pieces bb '(the brush position at the 0 degree position). Therefore, the brush positions in FIG. 10 (a) and FIG. 10 (b) are in a positional relationship rotated by 90 degrees with respect to each other. Has become.

 As a result of the armature current (rotor current) flowing between the rotor windings 4 connected by the brushes 8, the two types of symbols shown in FIG. 10, that is, the direction from the front to the back of the drawing The armature current on the coil side 41 determined by the symbol in the drawing and the symbol in the direction from the back to the front of the drawing generates torque by cutting off the magnetic flux by the field poles. In this case, at the 90-degree position shown in Fig. 10 (a), current flows in the same direction on the left and right two coil sides 41, and on the upper and lower two coil sides 41, respectively. , Currents flow in opposite directions. Therefore, a torque is generated in the rotor 6 in the counterclockwise direction by the field magnetic flux and the current flowing through the left and right coil sides 41 near the magnetic pole.

 On the other hand, at the 0-degree position shown in Fig. 10 (b), currents in opposite directions flow through the left and right two coil sides 41, and the upper and lower two coil sides 41 Current flows in the same direction. Therefore, the torque caused by the field magnetic flux and the current flowing through the coil side 41 immediately to the right and left of the magnetic pole cancel each other, and no rotation occurs.

Therefore, at the 90-degree position of the brush 8 shown in FIG. 10 (a), torque as a rotational force is generated, and at the 0-degree position shown in FIG. 10 (b), torque as the rotational force is generated. do not do. In FIG. 10 (a), an alternating current flows through the brush 8 and the rotor winding 4, but this alternating current is also a field current, and the direction of the current on the coil side 4i of the rotor winding 4 is changed. And the magnetic pole (direction of magnetic flux) are always in the same relationship, so that the direction of the generated torque is always the same even when the AC current flows. When the brush 8 is between the 0-degree position and the 90-degree position, the torque increases as the position approaches the 90-degree position, and the torque approaches 0 as the position approaches the 0-degree position. In FIG. 10, four rotor windings 4 and four commutator pieces 71 are illustrated with two field poles, but the present invention is not particularly limited thereto.

 For example, when the unit winding of the rotor winding 4 and a large number of commutator pieces 71 are provided, the brush 8 is gradually rotated from 0 to 90 degrees (or 0 to minus 90 degrees). Then, since the number of rotor windings 4 that cut off the magnetic flux gradually increases and increases, the generated torque gradually increases. In addition, when the brush 8 is gradually rotated from 90 degrees (or minus 90 degrees) to 0 degrees, the rotor winding 4 that cuts off the magnetic flux gradually decreases and becomes smaller. The torque gradually decreases.

 As a result, the rotation of the brush 8 shown in FIGS. 10 (a) and (b) corresponds to the axial movement of the brush 8 in the commutator 7 having the skew shown in FIGS. 8 and 9 described above. The torque of the rotor 6 changes to zero or increases depending on the axial movement position of the brush 8.

 When the brush position in the axial direction of the commutator 7 having the skew is in the 0-degree position shown in FIG. 10 (b) in place of the brush rotation, no torque is generated in the rotor 6. When the brush 8 is moved in the axial direction from this position, in other words, when the brush 8 is rotated clockwise from the position shown in FIG. 10 (b) to the position 90 degrees as shown in FIG. 10 (a), Rotor 6 generates counterclockwise torque.

 Although not shown in FIG. 10, the brush 8 is moved counterclockwise from the state shown in FIG. 10 (b) in the opposite direction to that shown in FIG. In this case, a clockwise torque is generated in the rotor 6. That is, depending on the axial movement position of the brush 8, the rotor 6 stops at the 0-degree position, the rotor 6 rotates forward (counterclockwise rotation) at the 90-degree position, and the rotor 6 rotates at the minus 90-degree position. Reverse rotation (clockwise rotation) occurs.

FIG. 11 shows the relationship between the brush position and the rotating direction of the rotor in the commutator 7 having the skew according to the second embodiment, and the stator winding and the rotor spring related thereto. And the relationship between the reactance and the rotational torque of the rotor.

 Fig. 11 (a-1) shows the electrical angle of the brush position 0 ° in the upper figure, and the state in which the reactance is maximized in the lower figure. In this case, no rotational torque is generated in the rotor.

 Fig. 11 (a-2) conceptually shows the above-mentioned state of 0 electrical angle using a transformer. In this case, the reactance becomes maximum.

 Fig. 11 (b-1) shows the electrical angle of the brush position 90 ° in the upper figure, and the state in which the reactance becomes smaller in the lower figure. In this case, a rotating torque is generated in the rotor.

 Fig. 11 (b-2) shows the brush position electrical angle exceeding 90 ° in the upper figure, and the state where the reactance is even smaller than that in the case of (b-1) in the lower figure. In this case, the rotor generates a stronger rotation torque than in the case of (b-1). Fig. 11 (b-3) conceptually shows the state of electrical angle of 180 ° using a transformer. In this case, the reactance is minimized.

 Fig. 11 (c) shows the electrical angle of the brush position minus 90 ° in the upper figure, and the state where the reactance becomes smaller in the lower figure. In this case, the rotor generates a reverse rotation torque as compared with the case (b-l).

 As is clear from FIG. 11, a wide range of torque control including the rotation direction consisting of forward rotation and reverse rotation is performed by the brush movement position along the axial direction of the skewed commutator 7 according to the second embodiment. Becomes possible.

 FIG. 12 shows the magnitude of torque generated in the rotor 6 with respect to the brush position corresponding to FIG. As shown in the figure, the torque increases in proportion to ± 90 ° around the brush position 0 °.

 In FIGS. 10 and 12, the electrical angle of the brush is between 0 ° and 90. (The same applies to minus 90 °).

By the way, as is well known in motors, the electrical angle 90 ° of the brush is an electrical angle at which a maximum rotational torque (hereinafter simply referred to as torque) is generated for efficiency. However, when the electrical angle of the brush is advanced beyond 90 °, the electrical angle is 90. As compared with the case of, the torque further increases and the rotation speed increases. The cause is as follows.

 First cause;

 To advance the electrical angle beyond 90 ° means to bring the magnetic poles of the same polarity closer to the S pole vs. S pole and the N pole vs. N pole as shown in Fig. 11 (b-2). As a result, the reactance of the coil is greatly reduced. Although this phenomenon is an example of an electrical angle of 180 °, it can be compared to the transformer in Fig. 11 (b-3) with the coils connected in reverse.

 As described above, when the electrical angle of the brush is advanced beyond 90 °, the reactance of the coil decreases in relation to the electrical angle (extremely when the electrical angle is 180 °) and flows into the coil. The current increases.

 Therefore, advancing the brush beyond the electrical angle of 90 ° will reduce the theoretical torque efficiency by selecting an electrical angle other than 90 °, but the torque itself will increase due to the increase in coil current. And the rotation speed increases.

 The second cause;

 The reactance of the rotor coil, which is not apparent in the low-speed rotation range of the motor, cannot be ignored in the high-speed rotation range, and the increase in the reactance delays the current and delays the effective effective magnetic flux.

 This is because even if the brush is supplying current to the rotor coil at an electrical angle of 90 °, which is theoretically the highest in efficiency, the generated magnetic flux is delayed. It corresponds to the magnetic flux generated when power is supplied to the rotor coil in a state of less than. As a result, torque decreases and rotation does not increase.

 In order to solve this, power is supplied with an electrical angle exceeding 90 °. As a result, the effective effective magnetic flux that is generated with a delay is equivalent to that obtained when the rotor coil is supplied with an electrical angle with good torque efficiency, and a decrease in torque efficiency can be prevented. Therefore, the torque increases and the rotation speed increases.

As mentioned above, in the second cause, the electric angle is advanced to offset the magnetic flux delay to advance: The reason from another aspect that power can be supplied is that a certain width of the brush in the direction of rotation of the commutator can be maintained, so that power can be supplied to the rotating commutator piece for a certain period of time. Therefore, the rotor coil is fed with the advanced electrical angle, and the time required for the magnetic flux generated late to grow into the effective effective magnetic flux can be secured. In one example of the actual experiment, when the electrical angle was advanced from 90 °, the rotation speed increased in proportion to the electrical angle, and the rotation increased to around 150 °.

 The cause of the increase in rotation when the electrical angle is advanced by 90 ° is that the first factor contributes greatly, and even if the torque efficiency is sacrificed, the reactive angle of the coil is greatly reduced by increasing the electrical angle.ぅ This is because extremely large torque is generated due to the large increase in coil current.

 (Electric drill provided with commutator motor of Embodiment 2)

 FIG. 13 shows an example of an electric drill to which the commutator motor according to the second embodiment is applied. A chuck 111 with a blade 110 attached thereto and a speed reducer 111 connected to the chuck 111 are shown. 2, motor body 1 1 3, commutator 7 with skew, and brush 8, except for brush 8, blade 1 110, chuck 1 1 1, reduction gear 1 1 2, motor body 1 13 The commutator 7 moves in the axial direction as a whole.

 In the above configuration, for example, if the blade 110 is pressed against the work (not shown), the commutator 7 at the reference position (0-degree position) with respect to the fixed brush 8 The motor moves relative to each other, and the rotor of the motor body 1 13 starts rotating (forward rotation). At the end of drilling of the workpiece, the load is removed and the commutator 7 and brush 8 return to their original positions (stop positions before rotation), and the rotation of the rotor stops. Thereafter, by pulling the blade 110 in the pulling-out direction, the commutator 7 moves relative to the brush 8 in the opposite direction, and the rotor starts to rotate in the reverse direction. By utilizing in this way, it is possible to automate the drilling rotation drive and the removal drive of the blade 110 by the reverse rotation in response to the pushing and pulling operation of the electric drill.

Next, a configuration in which the commutator 7 relatively moves with respect to the brush 8 will be specifically described with reference to FIGS. Fig. 14 shows brush 8 fixed as in Fig. 13. The brush 8 in contact with the commutator 7 is fixed, and the end of the shaft 114 of the rotor 6 determines the neutral position of the brush 8 with respect to the commutator 7. On the other hand, the other end of the shaft 114 and the end of the commutator 7 are provided with a gear 116 for power transmission, and the shaft end constitutes a bearing 117.

 On the other hand, a shaft 118 connected to the chuck 111 is provided with a gear 119, and a shaft end forms a bearing 117. Gears 116 and 119 are connected by gears 120 and 121. That is, the shaft 114 and the shaft 118 can be rotated separately via the bearing 117, but the shaft 118 and the shaft 114 can move in the axial direction at the same time. In this way, the rotational driving force of the motor is transmitted to the gears 116, 120, 121, and 119 to rotate the shaft 118 and the chuck 111, and at the same time, the chuck 111, the shaft 118, and the shaft 114 can move in the axial direction as a unit and can be commutated. The relative position of the brush 8 with respect to the child 7 can be changed. Here, the gears 116, 120, 121, and 119 work as a reduction gear here because of these gear ratios. FIG. 15 shows an example in which the position of the commutator 7 is fixed and the brush 8 is moved in the axial direction. The rotor 6, the commutator 7, and the gear 116 are simultaneously rotated to be in a fixed arrangement state. The other end of the shaft 118 connected to the jack 111 is provided with a spring 115 for determining the neutral position of the brush 8 with respect to the commutator 7. Are provided. Also in this configuration, the rotational driving force of the motor is transmitted to the gears 116 and 119 to rotate the shaft 118 and the chuck 111. At the same time, the chuck 111 and the shaft 118 can move in the axial direction, and the brush 8 The relative position of can be changed. Since the gear 119 moves on the gear 116 as the brush 8 moves in the axial direction, it is necessary to provide the gear 116 with a length corresponding to the amount of movement.

As is clear from FIGS. 14 and 15, torque control can be performed by making the brush 8 and the commutator 7 relatively movable in the axial direction. Therefore, as shown in Fig. 14, the brush 8 is fixed and the commutator 7 is moved in the axial direction. Alternatively, as shown in Fig. 15, the commutator 7 is fixed in the axial direction and the brush 8 is moved in the axial direction.In addition, both the brush 8 and the commutator 7 can be moved in the axial direction. It is also possible to perform torque control.

 In the description so far, the method of skewing the commutator pieces 71 has been described in one direction, for example, in the example of FIGS. The present invention is also applicable to a structure in which the skew of the commutator pieces 71 is provided in different directions such as clockwise and counterclockwise as shown in FIG.

 In the structure illustrated in FIG. 16, the center of the commutator 7 in the axial direction is set at a brush position of 90 degrees (120 degrees or 150 degrees may be used), and both ends in the axial direction are set at a brush position of 0 degrees. For example, as the brush 8 is moved to the right from the left end of the commutator, a torque is gradually generated, the maximum torque is at the center in the axial direction, and further, as the brush 8 is moved to the right, the torque is reduced. The torque is assumed to be 0. Further, as another example, the torque increases as the tonole 0 and the brush 8 are moved right and left at the center in the axial direction, and the maximum torque can be obtained at the left and right ends of the commutator.

 In the above description, a series-wound motor has been assumed based on the configuration of FIG. 7, but the stator winding 1 and the brush 8, the commutator 7, and the rotor winding 4 are connected to the AC power supply. The present invention can be similarly applied to a parallel motor, that is, a so-called shunt motor.

 (Embodiment 3).

 (Example 1)

 FIG. 17 is a conceptual exploded view of an AC commutator motor according to Embodiment 3 of the present invention. An AC commutator motor has a structure in which a stator of an induction motor and a rotor of a DC motor are combined. Even though it is an AC motor, it has a commutator and a brush. FIG. 17 shows a series winding 4 in which a field winding 1 and a rotor winding 4 are connected in series. ''.

In Fig. 17! A rotor 6 having a rotor core 5 with a rotor core 4 wound around a stator 3 having a stator core 2 with a field winding 1 wound thereon is rotatable. set on Has been. The rotor 6 is provided with a commutator 7 and a pair of brushes 8, and the rectifier 7 and the pair of brushes 8 are electrically connected to the rotor winding 4. The commutator 7 has a plurality of commutator pieces 71. One end of the field winding 1 is connected to an AC power supply (not shown), and the other end is connected to one brush 8. The other brush 8 is connected to an AC power supply. The AC power supply path is provided with a power supply switch 9 for the AC commutator motor.

 Here, in the AC commutator motor shown in FIG. 17, the brush 8 has a structure capable of rotating (moving) in the circumferential direction of the commutator 7. That is, the pair of brushes 8 is configured to be able to rotate in the circumferential direction of the commutator 7 regardless of the rotation or stop of the commutator 7 while maintaining the positional relationship between the brushes.

 The relationship between the rotational position of the brush 8 and the generated torque will be described with reference to FIG. In Fig. 18, the field poles of the stator core 2 are N and S poles. The rotor core 5 is provided with four rotor windings 4 having a two-layer winding coil side 27 2, and four commutator strips from the rotor winding 4 via lead wires 27 3. 7 1 is connected. FIG. 18 (a) shows a state in which the brush 8 is in contact with the right and left commutator pieces &, a 'in the figure (referred to as a 90-degree brush position). In FIG. 18 (b), The figure shows a state in which the brush 8 is in contact with the upper and lower commutator pieces b and b '(referred to as a 0-degree brush position). Therefore, the brush positions in Fig. 18 (a) and Fig. 18 (b) have a 90-degree different position, and the two-field pole has a 90-degree electrical angle variation. I have.

 Here, the brush position having an electrical angle of 0 degrees corresponds to the base position in the claims, and the mutual relationship between the magnetic flux created by the field winding 1 and the magnetic flux created by the rotor winding 4. The angle is substantially parallel, and the magnetic pole generated by the magnetic flux generated by the field winding 1 and the magnetic pole generated by the magnetic flux generated by the rotor winding 4 have an attractive relationship. Say. The brush position having an electrical angle of 90 degrees refers to a state in which the mutual angle between the magnetic flux generated by the field winding 1 and the magnetic flux generated by the rotor winding 4 is substantially perpendicular.

In such a configuration, between the rotor windings 4 connected by brushes 8 As a result of the armature current (rotor current) flowing, there are two types of symbols indicating the direction of the armature current on the coil side 272, namely, a symbol from the front to the back of the drawing, and a symbol from the back to the front of the drawing. The torque is generated by the armature current determined by the sign of the direction toward and the magnetic flux by the field pole.

 At the 90-degree brush position shown in Fig. 18 (a), current flows in the same direction on the two coil sides 272, which form the left and right two layers, respectively, and the upper and lower two layers form the two coil sides. Currents in opposite directions flow through the coil sides 27 2. Therefore, in this case, a current flowing through the left and right coil sides 272 immediately near the magnetic pole of the field magnetic flux generates a counterclockwise torque in the rotor 6 as indicated by the arrow K.

On the other hand, at the 0-degree brush position shown in Fig. 18 (b), current flows in opposite directions on the two coil sides 272, which form two layers on the left and right, respectively. A current in the same direction flows through each of the coil sides 27 2 of the book. Therefore, in this case, the torque generated by the field magnetic flux and the current flowing through the left and right coil sides 272 near the magnetic pole cancel each other and no rotation occurs. '' Thus, at the 90-degree brush position shown in Fig. 18 (a), torque is generated, and at the 0-degree brush position shown in Fig. 18 (b), torque is generated. do not do. When the brush 8 is located between the 0-degree position and the 90-degree position, the rotational force increases as the brush 8 approaches the 90-degree position, and the brush 8 approaches the 0-degree position. , The rotational force is close to zero. Further, in practice, the maximum torque is generated in the rotor ⁶ when the brush position is set to an angle position of 120 degrees to 150 degrees which is 90 degrees or more. The force at which the maximum tonolek is obtained at a position far from 90 degrees depends on the inductance of the field winding 1 and the like.

 Although not shown in FIG. 18, the brush 8 is moved from the 0 degree state shown in FIG. 18 (b) in the counterclockwise direction opposite to that of FIG. When the rotor 6 is located at the 0-degree position, a rotational force in the clockwise direction opposite to the arrow K is generated in the rotor 6.

As described above, by changing the rotation position of the brush 8, the rotor can be controlled to any of the state without torque, the normal rotation state, and the reverse rotation state. You That is, when the brush position is 0 degree, no rotating force is generated in the rotor 6, and the brush rotates in the forward direction as the brush is rotated from the 0 degree position to plus 90 degrees and further to 120 degrees or 150 degrees. The torque increases, and the torque in the reverse direction increases as the bushing is turned from the 0-degree position to 190, further to 120 or 150 degrees.

 Fig. 19 illustrates the relationship between the brush position and the rotating direction of the rotor, and the related relationship between the stator winding and the reactance of the rotor winding and the rotating tonnolek and exciting current of the rotor. Is what you do.

 When a current flows through the field winding 1, a magnetic flux is generated in the stator 3. Similarly, when a current is passed through the rotor winding 4, an electromagnet is generated in the rotor 6. As shown in FIG. 19 (a), when the brush 8 is located at an electrical angle of 0 degree, the magnetic circuit composed of the stator 3 and the rotor 6 maintains a stable suction state. At this time, the reactance becomes maximum and the exciting current value for generating torque is extremely small, and no rotational torque is generated on the rotor.

 However, as shown in FIG. 19 (b) or FIG. 19 (c), when the brush 8 is located at an electrical angle of 90 degrees or 190 degrees, for example, the magnetic circuit is opened and the field pole is opened. And the electromagnet attract. At this time, the reactance becomes small, and an exciting current corresponding to the magnetic gap of the magnetic circuit flows, and a torque corresponding to the exciting current is generated.

 By the way, as is well known in electric motors, the electrical angle 90 of the brush is an electrical angle that generates the maximum torque in terms of efficiency. However, when the electrical angle of the brush is advanced beyond 90 °, for example, as shown in Fig. 19 (d), the torque increases further compared to the case of 90 ° electrical angle, and the rotation speed increases. Speed increases. The cause is as follows.

 First cause;

When the electrical angle is advanced beyond 90 °, as shown in Fig. 19 (d), the S pole vs. S pole, N pole vs. N pole are brought closer to the magnetic poles of the same polarity, and as a result, The reactance of the coil is greatly reduced. That is, when the electrical angle of the brush is advanced beyond 90 °, the coil reactance decreases in relation to the electrical angle (electrical angle of 180 °). °), the current flowing through the coil increases. Therefore, advancing the brush beyond the electrical angle of 90 ° will reduce the theoretical torque efficiency by selecting an electrical angle other than 90 °, but will increase the torque of the coil by increasing the coil current. It will increase itself and the rotation speed will increase.

 The second cause;

 The reactance of the rotor coil, which has not been revealed in the low-speed rotation range of the motor, cannot be ignored in the high-speed rotation range, and the increase in the reactance delays the current and delays the effective effective magnetic flux. Therefore, even if the brush is supplying current to the rotor coil at an electrical angle of 9'0 °, which is theoretically the maximum efficiency, the generated magnetic flux is delayed, and the effective effective magnetic flux contributing to the torque is the electrical angle 90 0 It corresponds to the magnetic flux generated when power is supplied to the rotor coil in a state where the temperature is less than 0 °. As a result, the torque decreases and the rotation does not increase.

 In order to solve this, power is supplied with an electrical angle exceeding 90 °. As a result, the effective effective magnetic flux that is generated with a delay is equivalent to that obtained when the rotor coil is supplied with an electrical angle with good torque efficiency, and a decrease in torque efficiency can be prevented. Therefore, the torque increases and the rotation speed increases. '

As described above, in the second cause, power can be supplied by advancing the electrical angle and canceling out the delay in magnetic flux.The reason from another aspect is that the width of the brush in the rotational direction of the commutator can be secured to some extent. This allows power to be supplied to the rotating commutator piece for a certain period of time. Therefore, the rotor coil is fed with the advanced electrical angle, and the time required for the magnetic flux generated late to grow into the effective effective magnetic flux can be secured. In one example of the actual experiment, when the electrical angle was advanced from 90 °, the rotation speed increased in proportion to the electrical angle, and the rotation increased to around 150 °. The cause of the increase in rotation when the electrical angle is advanced by 90 ° is that the first factor contributes greatly, and at the expense of torque efficiency, the coil electrical reactance is greatly reduced by advancing the electrical angle. This is because an extremely large torque is generated due to a large increase in the coil current accompanying this. Next, a first embodiment of a configuration for rotationally positioning the brush 8 which is a main part of the present invention will be described with reference to FIG.

 As shown in FIG. 20, the pair of brushes' 8, 8 is supported by a brush support 210. The brush support 210 has a structure capable of rotating in the circumferential direction of the commutator 7, and the brush 8 rotates in the circumferential direction of the commutator 7 by rotating the brush support 210. Is done. Reference numeral 211 denotes a rotating shaft of the commutator motor.

 The brush position shown in black in FIG. 20 corresponds to the 0-degree position shown in FIG. 18 (b), and in this state, the rotor 6, that is, the commutator 7 is stopped. . By rotating the brush support 210 in the direction of arrow S1, the right brush 8 is positioned at, for example, an electrical angle of 90 ° (indicated by the symbol C a). C b), and causes the commutator 7 and, consequently, the rotor 6 to generate a driving torque in the forward rotation direction indicated by the arrow D1 corresponding to the brush angle, thereby rotating the rotor 6 in the direction D1. Can be inverted. On the other hand, by rotating the brush support 210 in the direction of arrow S2, the right brush 8 is positioned at, for example, an electrical angle of 90 ° (indicated by the symbol Cb). 8 is located at the position indicated by the symbol C a), the rectifier 7 fin, and the rotor 6 by causing the drive torrent in the reverse direction indicated by the arrow D 2 corresponding to the brush angle to the rotor 6. 6 can be reversed in the D2 direction.

A plurality of teeth are formed on the outer periphery of the brush support 210, and a gear 2 12 is connected to the outer periphery of the brush support 210. The gear 2 12 is fixed to a rotating shaft 2 14 of a servo motor 2 13 as a brush driving motor capable of rotating forward and backward. The servo motor 213 is started by a power switch different from the power switch 9 of the commutator motor (see Fig. 17), and the servo motor 213 is powered by the power switch of the commutator motor. By the time 9 is put in, it has already been started. At this time, the servomotors 2 13 are controlled so that the brush 8 is at the base position corresponding to the electrical angle of 0 degree. That is, in the first embodiment, the rotating position of the brush 8 is controlled from the base position (electrical angle 0 °) to any positive electrical angle position by the electric motor 2 13 different from the commutator motor. . Here, as described above, in the initial state when the power of the commutator motor is turned on when the power switch 9 is turned on, the servomotor 2 13 is already started, and the control by the servomotor 2 13 is At the time when the power switch 9 is turned on, the rotating position of the brush support 210 is positioned so that the brush 8 is held at the electrical angle 0 ° shown in black in FIG. Therefore, at this time, as described with reference to FIG. 19 (a), the reactance of the stator winding and the rotor winding becomes maximum, and the exciting current value becomes extremely small. Therefore, the inrush current at startup can be suppressed to an extremely small value.

 After the power switch 9 is turned on, the brush support 210 is driven to rotate by the servomotor 213 so that the rotation position of the brush 8 is increased from the base position (electrical angle 0 °). By controlling to a minus arbitrary electric angle position, a forward or reverse rotation torque corresponding to the brush angle position is generated in the rotor 6, and the speed control of the commutator motor is executed.

 Thus, in the first embodiment, in the initial state when the power of the commutator motor is turned on, the brush 8 is held at the electrical angle of 0 ° by the control of another motor. Inrush current can be suppressed to an extremely small value.

 The mechanism for transmitting the rotation from the electric motor 21 to the brush support 210 is optional. For example, a mechanism using friction instead of a gear may be adopted. Instead of using a servo motor capable of rotating forward and reverse, an appropriate forward / reverse switching mechanism may be inserted between the electric motor 2'13 and the brush support 210.

 (Example 2)

 Next, a second embodiment of the commutator motor according to the third embodiment of the present invention will be described with reference to FIG. In the second embodiment, the commutator motor according to the present invention is applied to an accelerator mechanism of an automobile.

Also in the electric motor according to the second embodiment, the pair of brushes 8 is supported by the brush support 210. Brush support 2 1 0 is summer and circumferentially rotatable structure of the commutator ^7, by the brush supporting member 2 1 0 is rotated, the brush 8 of the commutator 7 It is rotated in the circumferential direction. The brush position shown in black in FIG. 21 corresponds to the 0-degree electrical angle position shown in FIG. 18 (b), and in this state, the rotor 6, that is, the commutator 7 stops. ing. When the brush 8 is positioned at an appropriate electrical angle こ と by rotating the brush support 210 in the direction of the arrow S1, the rotor 6 can be normally rotated in the direction of the arrow D1. On the other hand, when the brush 8 is positioned at the electrical angle of 10 by rotating the brush support 210 in the direction of arrow S2, the rotor 6 can be rotated in the direction of arrow D2.

 A pair of springs 215 as an elastic member is connected to the brush support 210, and when no external force is applied by the urging force of the springs 215, the brush 8 turns the electrical angle to 0 °. It is held in position. Therefore, in the initial state when the power is turned on, the brush 8 is held at the electrical angle of 0 °, and the rush current when the power is turned on can be suppressed to an extremely small value.

 Next, a configuration for rotating the brush support 210 in piles by the holding force of the panel 2 15 will be described. A forward rod 220 a and a reverse rod 220 b are fixed to the brush support 210 so as to extend, for example, in a tangential direction of the brush support 210. Therefore, when an external force is applied to the advance rod 220a in the direction in which it extends (the direction of the arrow E), the brush support 210 (brush 8) is rotated in the direction of the arrow S1, whereby the commutator is rotated. 7 can be rotated forward (corresponding to forward movement) in the direction of arrow D1. Further, when an external force is applied to the reversing rod 220b in the direction of arrow E, the brush support 210 (brush 8) is rotated in the direction of arrow S2, whereby the commutator 7 is moved in the direction of arrow D2. Can be reversed (corresponding to reverse).

A plate 222 for receiving the pressing force of the pressing port 221 is provided at each end of the forward rod 220a and the backward port 222b. The pressing rod 2 2 1 is connected to the accelerator connecting port 2 ′ 2 3 via the rotating shaft 2 2 4, and the pressing port 2 2 1 and the axial connecting rod 2 2 3 are integrated. It is configured to be movable in the directions indicated by arrows Fa and Fb. The accelerator connection port 223 is connected to the accelerator pedal 230 via an appropriate mechanism (not shown). Pressing port 2 2 1 The front and rear switching rods 2 25 are fixed to. The front-rear switching rod 2 25 is movable in the directions fc indicated by arrows R a and R b in conjunction with the gear change of the vehicle traveling forward and backward.

 In the strong configuration, when the illustrated forward / reverse gear is in the neutral position, the pressing port 2 221 is at the position indicated by the solid line. When the forward / reverse gear is shifted to the forward side, the forward / backward switching rod 2 25 moves in the direction of Ra, whereby the pressing rod 2 2 1 is moved forward about the rotating shaft 2 2 4 as a fulcrum. The plate is rotated to a position directly facing the plate 22 of 22a. In this state, when the accelerator pedal 230 is depressed, the accelerator connecting port 2 23 and the pressing port 2 21 move in the direction shown by the arrow Fa in a bent state. Due to this movement, the pressing rod 2 21 presses the plate 2 2 2 of the forward rod 2 220 a, and as a result, the brush support 210, that is, the brush 8 is moved to a position corresponding to the amount of depression of the brush 23.0. It turns in the direction of arrow S1. Therefore, the commutator 7 and the rotor 6 generate a forward rotation torque corresponding to the brush angle position, rotate the rotor 6 forward in the direction indicated by the arrow D1, and move the vehicle forward.

On the other hand, when the forward / reverse gear is shifted to the reverse side, the forward / backward switching rod 2 25 moves in the Rb direction, whereby the pressing rod 2 21 moves backward with the rotating shaft 2 24 as a fulcrum. The plate is rotated to a position directly facing the plate 220 of 22 b. When the accelerator pedal 230 is depressed, the accelerator connecting port 2 23 and the pressing port 2 21 move in the direction shown by the arrow Fa in a bent state. Due to this movement, the pressing rod 2 2 1. 1 presses the plate 2 2 2 of the reverse opening 2 2 0 b, and as a result, the brush support 2 1 ′ 0, that is, the brush 8 is adjusted according to the amount of depression of the accelerator pedal. Rotate in the direction of arrow S2 to the position. Therefore, a reverse torque is generated in the commutator 7 and the rotor ⁶ in accordance with the brush angle position, and the rotor ⁶ is rotated in the direction indicated by the arrow D2 to move the vehicle backward.

As described above, in the second embodiment, in the initial state when the power of the commutator motor is turned on, the brush 8 is held at the electrical angle of 0 ° by the panel ² 15. Can be suppressed to an extremely small value. (Example 3)

 Next, a third embodiment of the commutator motor according to the third embodiment of the present invention will be described with reference to FIGS. 22 and 23. In the third embodiment, another configuration is adopted as a configuration for rotating the brush support 210 against the holding force of the panel 215. The other configuration is the same as that of the second embodiment shown in FIG. 21 and duplicate description will be omitted.

 The driven wheel 240 is fixed to the same shaft as the brush support 210. Therefore, when the driven arm 240 is rotated, the brush support 210 (brush 8) is rotated. The driven vehicle 240 is connected to the driving vehicle 242 by an endless noselet 241.

 The pressing rod 2 4 3 is connected to the axel connecting rod 2 4 5 via the rotating shaft 2 4 4, and the pressing port 2 4 3 and the axel connecting port 2 4 5 are integrally formed. It is configured to be movable in directions indicated by arrows F a and F b. The accelerator connecting rod 245 is connected to the accelerator pedal 230 via an appropriate mechanism (not shown). As shown in FIG. 23, the pressing port 243 is passed through a hole 247 formed in the front / rear switching port 246. The front / rear switching port 2246 is movable in the directions indicated by arrows R a and R b in conjunction with the gear change of the vehicle in the forward / reverse direction, as described above.

In such a configuration, when the forward-reverse gear (not shown) is located at the neutral position, the pressing port 243 is at the position shown in FIG. When the forward / reverse gear is changed to the forward side, the front / rear switching port 2 25 moves in the R a direction, whereby the pressing port 2 4 3 moves about the rotation axis 2 4 4 as a fulcrum. Pivoted in the direction. When the accelerator pedal 230 is depressed, the accelerator connecting port 245 and the pressing port 243 move in the bent direction in the direction indicated by the arrow Fa. Due to this movement, the pressing rod 243 presses the outer periphery of the driving wheel 242, and as a result, the driving wheel 242 rotates in the direction shown by the arrow S1. As a result, the driven wheel 240 rotates in the direction of arrow S1, and the brush support 210, that is, the brush 8 also rotates in the direction of arrow S1 to a position corresponding to the amount of depression of the accelerator pedal 230. Is done. Therefore, commutator 7 and rotor 6 are The forward rotation torque is generated, the rotor 6 rotates forward in the direction indicated by the arrow D1, and the vehicle moves forward.

 On the other hand, when the forward / reverse gear is changed to the reverse side, the forward / backward switching rods 2 and 25 move in the Rb direction, whereby the pressing rod 2443 moves about the rotation axis 2444 as a fulcrum in the Rb direction. It is rotated in the direction. When the accelerator pedal 230 is stepped on, the accelerator connecting port 2 45 and the pressing port 2 4 3 move in the direction shown by the arrow Fa in a bent state. Due to this movement, the pressing rod 243 presses the outer periphery of the driving wheel 242, and as a result, the driving wheel 242 rotates in the direction shown by the arrow S2. As a result, the driven vehicle 240 rotates in the direction of arrow S2, and the brush support 210, ie, the brush 8, also rotates in the direction of arrow S2 to a position corresponding to the amount of depression of the accelerator pedal 230. . Therefore, a reverse torque corresponding to the brush angle position is generated in the commutator 7 and the rotor 6, and the rotor 6 is reversed in the direction shown by the arrow D2, and the vehicle moves backward.

 As described above, in the third embodiment as well, in the initial state when the power of the commutator motor is turned on, the brush 8 is held at the electrical angle of 0 ° by the panel 2 15. Can be suppressed to an extremely small value.

 FIG. 24 is a modification of the third embodiment shown in FIG. 22, in which a driven wheel 240 fixed to the same shaft as the brush support 210 is a gear. In addition, the drive wheel 250 is meshed with the driven wheel 240, and the rotation of the drive gear 250 is transmitted to the driven wheel 240 by a gear mechanism. Other configurations are the same as those in FIG. In addition, a driven vehicle 240 and a driven vehicle 250 whose outer periphery is formed so as to have a large friction coefficient are employed, and the rotation of the driven vehicle 250 is driven by the friction by the driven vehicle 240. It may be transmitted to.

In the above-described third embodiment, a series-wound motor has been described. However, the present invention can also be applied to a divided-winding motor in which the field winding 1 and the rotor winding 4 are connected in parallel. . Industrial applicability As described above, the commutator motor according to the present invention is useful for parking brakes, β-action drills, and the like.

Claims

The scope of the claims

1. The field winding wound on the stator is connected to the rotor winding wound on the rotor via the brush commutator, and the AC power is applied to the field winding and the rotor winding. 5 commutator motor

 While configuring the brush to be rotatable in the circumferential direction of the commutator,

 The brush is provided with brush urging means for applying a predetermined contact pressure to the brush so that a frictional force with which the brush located at the base position rotates with the commutator is obtained between the brush and the commutator, and the brush is rotated by the brush urging means. The commutator β motive, characterized in that the stator is held in a stopped state.

2. The commutator motor according to claim 1, wherein the rotor is held in a stopped state by generating a torque in a direction opposite to a direction in which the brush rotates. .

Five

 '

3. The brush rotates in one direction from the base position in the first operation to generate a driving torque on the rotor, and rotates in the other direction from the base position in the second operation in the second direction. 2. The commutator motor according to claim 1, wherein the commutator motor operates by generating a braking torque on the rotor and returning to the base position by releasing the first or second operation. 0

4. The brush rotates in one direction from the base position in the first operation to generate a driving torque on the rotor, and rotates in the other direction from the base position in the second operation to rotate the rotor. 3. The commutator motor according to claim 2, wherein the commutator motor operates so as to generate a braking torque at the vehicle and return to the base position by releasing the first or ^second operation. Five

5. The commutator motor according to claim 1, wherein the base point position is a position corresponding to an electrical angle of approximately 0 degrees.

6. Commutator composed of a stator winding wound on a stator core, a rotor winding wound on a rotor core, and a plurality of commutator pieces, and connected to the rotor winding. And a brush contacting the commutator, wherein an AC power source is connected to each of the stator winding and the rotor winding.

 The stator winding and the rotor winding are connected by direct winding or split winding,

 Each commutator piece of the commutator has a skew in the axial direction,

 A commutator motor characterized in that the brush and the commutator are relatively movable along the axial direction of the commutator.

7. The angle of the skew of each commutator piece should be within the relative axial movement range of the brush and the commutator. 7. The commutator according to claim 6, wherein the number of the coils is an angle corresponding to a difference of 90 degrees or more in the electrical angle of the rotor winding connected to the commutator piece. Electric motor. '

8. The relative axial movement range between the brush and the commutator is 90 degrees or more around the brush position at an electrical angle of about 0 degrees in the rotor winding. 7. The commutator motor according to item 7.

9. The skew of the commutator formed by each commutator piece is twisted clockwise in the circumferential direction of the commutator from one end in the axial direction of the commutator to the other end, and then twisted counterclockwise in the circumferential direction. 7. The commutator motor according to claim 6, wherein:

10. The skew of the commutator formed by each commutator piece was formed so that it twisted clockwise in the circumferential direction of the commutator from one end in the axial direction of the commutator to the other end, and then twisted counterclockwise in the circumferential direction. 8. The commutator motor according to claim 7, wherein: '

1 1. The skew of the commutator formed by each commutator piece was formed so that it was twisted clockwise in the circumferential direction of the commutator from one end in the axial direction of the commutator to the other end, and then counterclockwise in the circumferential direction. 9. The commutator motor according to claim 8, wherein:

1.2. An electric drill, comprising the commutator motor according to any one of claims 6 to 11 as a power source.

1 3. The field winding wound on the stator is connected to the rotor winding wound on the rotor via a brush and a commutator, and AC power is supplied to the field winding and the rotor winding. In the connected commutator motor,

 While configuring the brush to be rotatable in the circumferential direction of the commutator,

 Brush holding means for holding the brush so that the brush is located at a base position corresponding to an electrical angle of approximately 0 degrees when the AC power is turned on;

 After turning on the AC power, brush rotation driving means for controlling the rotation position of the bra,; / to generate forward rotation torque and / or reverse rotation torque on the rotor, Commutator motor.

14. The brush holding means and the brush rotation driving means have a brush driving motor different from the commutator motor, and the brush driving motor moves the brush to the base position when the AC power is turned on. 14. The commutator motor according to claim 13, wherein the brush support that supports the brush is controlled so as to be held and rotated to an arbitrary rotation position after the AC power is turned on. 15. The brush holding means has an elastic member for holding the brush at a base position,

The brush rotation drive unit is configured to rotate the brush against an elastic holding force of the elastic member. The method according to claim 13, further comprising a mechanism for controlling a rotation position.