JP4091817B2 - 2-phase motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a two-phase motor used for, for example, a vibration motor, and more particularly to a two-phase motor that can reliably start the motor and can effectively use the cogging torque, which has been conventionally unnecessary, as the rotational torque. It relates to the motor.
[0002]
[Prior art]
Conventionally, as this type of known document, for example, there is a two-phase motor disclosed in Patent Document 1. The invention disclosed in Patent Document 1 aims to easily start a two-phase motor and to reduce cogging torque to reduce motor rotation unevenness.
[0003]
As means for achieving these objects, in the invention described in Patent Document 1, the outer peripheral surface of the core magnetic pole is formed into a perfect circle along the inner peripheral surface of the rotor, and one side surface of the outer peripheral surface of the core magnetic pole is formed. It is set as the structure which provided the overhang | projection part.
[0004]
[Patent Document 1]
JP-A-8-126280
[0005]
[Problems to be solved by the invention]
However, in the two-phase motor described in Patent Document 1, the shape of the armature core is intended to improve the torque characteristics by utilizing the magnitude of the magnetic energy due to the presence or absence of a notch at the tip of the armature core. There is a problem that the manufacturing cost is likely to increase.
[0006]
Conventionally, the generation of cogging torque was considered to be one factor that hinders the driving torque of the motor. Therefore, it is common that the cogging torque is made as small as possible so that the driving torque inherent in the motor is fully exhibited. It was. However, such a method of simply reducing unnecessary cogging torque has a limit in obtaining sufficient driving torque.
[0007]
The present invention is for solving the above-described conventional problems, and in the state where the cogging torque, which has been conventionally unnecessary, is intentionally left, good starting characteristics can be obtained, and the cogging torque can be used to obtain a large amount. An object of the present invention is to provide a two-phase motor capable of generating a driving torque.
[0008]
[Means for Solving the Problems]
  The present inventionThe two-phase motor includes a rotor that rotates together with the rotating shaft, and a stator that is a fixed side.
  One of the rotor and the stator has a pair of magnetic arm portions arranged in a direction orthogonal to the rotation axis and at an angle of 180 degrees with each other, a coil wound around each arm portion, and a magnetic material A pair of magnetic members formed of
  The other of the rotor and the stator is provided with two magnets facing the tip of the arm part, and the two magnets have different magnetic poles on the magnetized surface facing the arm part and two magnets. Each of the magnetized surfaces is formed in a range of 180 degrees toward the rotation direction of the rotor,
  The centers of the arms and the centers of the magnetic members are arranged at intervals of an angle α in the rotation direction of the rotor, and the angle α is not less than 60 degrees and not more than 80 degrees.It is characterized by this.
[0009]
In this case, when the rotor is rotated, a first cogging torque is generated between the stator and the rotor according to the rotation angle of the rotor, and a second cogging torque is generated between the plate and the rotor. Cogging torque is generated, and when the first cogging torque and the second cogging torque are combined, the second cogging torque does not cancel the first cogging torque. The plate is arranged.
[0010]
In order to rotate the motor smoothly, the combined cogging torque obtained by combining the first cogging torque and the second cogging torque is the same positive direction as the rotation direction of the rotor across 0 [N · m]. And a component indicating a reverse direction that prevents rotation of the rotor, and an area surrounded by at least the forward direction component and 0 [N · m] is the reverse direction component. The area is larger than the area surrounded by 0 [N · m].
[0011]
Then, the generated torque generated only by the interaction between the magnetic flux generated by the drive current flowing in the coil of the stator and the magnet of the rotor and the combined torque are output as rotational torque.
[0012]
  In the present invention, the angle α is preferably 75 degrees.
[0014]
  further,Give the coil a drive current that changes in a sine waveDriving meansIn the drive means,Drive currentThe direction ofSwitching at half cycle of sine wave or at earlier timingBeThose are preferred.
  In the above configuration, a larger rotational torque can be obtained.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a transverse sectional view showing a two-phase motor as an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view taken along line II-II in FIG. FIG. 3 is a cross-sectional view of a two-phase motor similar to FIG. 1, and shows a state in which the rotor is rotated 90 ° counterclockwise. 4 is a cross-sectional view of a two-phase motor similar to FIG. 1, where A is a state in which the rotor is rotated by a rotation angle α, B is a state in which the rotor is rotated by a rotation angle α + 90 °, and C is a rotation of the rotor. A state in which the angle α + 180 ° is rotated, and D indicates a state in which the rotor is rotated by a rotation angle α + 270 °.
[0016]
A two-phase motor 1 shown in FIGS. 1 and 2 is a so-called outer rotor type two-phase two-pole brushless motor. Reference numeral 2 denotes a rotating shaft, and the center portion of the cup-shaped frame 3 is fixed to the rotating shaft 2 with the opening portion directed downward. The rotating shaft 2 is rotatably supported by bearing portions 4 a and 4 b of a bearing base 4 provided inside the frame 3. The bearing base 4 is fixed to a base member 20 such as a mechanism chassis.
[0017]
Bipolar magnets M1 and M2 are fixed to the inner wall 3a of the frame 3 in an integrated state in a cylindrical shape. The frame 3 and the magnets M1 and M2 form a rotor R of the two-phase motor 1. For example, one magnet M1 is magnetized with an N pole on the inner circumference and an S pole on the outer circumference, and the other magnet M2 is magnetized with an S pole on the inner circumference and an N pole on the outer circumference. In FIG. 1, the joint surfaces of the magnet M1 and the magnet M2 are indicated by Ma and Mb. It is also possible to magnetize the inner circumference side of the right half of the already integrated cylindrical magnet to the S pole and the inner circumference side of the left half to the N pole. Mb is the boundary between both magnetic poles (N and S poles).
[0018]
An armature core 5 made of a magnetic material is fixed to the bearing base 4. The armature core 5 is provided with arm portions 5a and 5b protruding in both directions. The arms 5a and 5b are fixed in a state of being aligned with the X axis shown in the figure. The arms 5a and 5b are provided with coils C1 and C2. When the armature core 5 has a cylindrical portion 5c at the center thereof, and the cylindrical portion 5c and the arm portions 5a and 5b are integrally formed of a magnetic material, the arm portion is provided. Since the magnetic flux penetrating through 5a and the arm portion 5b is formed in the same direction along the X axis in the figure, the coil C1 and the coil C2 are wound as a single coil by winding one wire in the same winding direction. It may be formed, or one coil (coil C1 or coil C2) may be provided on one of the arm part 5a or the arm part 5b.
[0019]
Outside the two-phase motor, driving means 10 including a driving signal generation unit 11 and a motor driver 12 is provided. The drive signal generator 11 generates a drive signal having an AC waveform having a predetermined amplitude and period and outputs the drive signal to the motor drive 12. The motor drive 12 generates a drive current corresponding to the drive signal output from the drive signal generation unit 11 and supplies it to the coils C1 and C2.
[0020]
When the drive current is supplied to the coils C1 and C2, magnetic fluxes in the same direction are generated in the arm portions 5a and 5b of the armature core 5. Therefore, when the arm portion 5a side is magnetized to the S pole, the arm portion 5b side is magnetized to the N pole, and when the arm portion 5a side is magnetized to the N pole, the arm portion 5b side is magnetized to the S pole.
[0021]
That is, the armature core 5 and the coils C1 and C2 form a stator St of the two-phase motor 1.
[0022]
As shown in FIG. 1, in the space between the magnets M1 and M2 on the rotor R side and the stator St and at a position shifted from the X axis in the counterclockwise direction by the mounting angle α, the magnets M1 and M1 are located. Plates 8a and 8b facing M2 are provided. The plates 8a and 8b are formed of a magnetic member that is magnetically attracted when approaching the magnet, and can be formed by vertically raising a part of the base member 20 made of, for example, a steel plate or the like in the Z direction. The plate 8a and the plate 8b are provided symmetrically with respect to the rotating shaft 2, and in the two-phase motor 1 shown in FIG. 1, the mounting angle α of the plate 8a is set to about 75 °. .
[0023]
The operation of the two-phase coil will be described.
FIG. 5 is a graph showing the torque generated by only the interaction between the magnetic flux generated by the drive current flowing in the coil of the stator St and the magnet of the rotor. FIG. 6 is a graph showing the cogging torque generated in the rotor for each rotation angle of the rotor, where Ts is the stator cogging torque generated by the interaction with the stator, Tp is the plate cogging torque generated by the interaction with the plate, and Tc is the stator. This is a combined cogging torque of the cogging torque and the plate cogging torque, and indicates the total sum of the cogging torque generated in the rotor.
[0024]
FIG. 7 is a graph showing the composition of torque generated in the two-phase motor when the direction of the drive current is not switched, where T0 is the generated torque, Tc is the combined cogging torque, and T is the rotational torque generated in the two-phase motor ( Torque sum). FIG. 8 is a graph showing the rotational torque generated in the two-phase motor when the direction of the drive current is switched every half cycle (180 °), where T0 is the generated torque, Tc is the combined cogging torque, and T is the two-phase motor. The rotational torque is shown.
[0025]
5 to 8, the horizontal axis represents the rotor rotation angle θ [°], and the vertical axis represents the torque [μN · m]. Further, regarding the relationship of the rotation angle between the rotor R and the stator St, the state shown in FIG. 1 is set to a rotation angle θ = 0 °.
[0026]
First, the characteristics of the two-phase motor with the plate removed will be described.
When a drive current is passed through the coils C1 and C2 on the side of the stator St shown in FIGS. 1 and 2 and magnetic flux is generated in the same direction in the arms 5a and 5b, the magnetic flux generated by the current flowing through the coils, the magnet of the rotor R, The generated torque T0 as shown in FIG. 5 is generated only by this interaction. For example, the rotor R is rotated in the clockwise direction. The generated torque T0 is approximately proportional to the current value of the drive current flowing through the coils C1 and C2.
[0027]
As shown in FIG. 5, when the rotation angle θ of the rotor R with respect to the stator St is θ = 0 ° (= 360 °: the state shown in FIG. 1) and θ = 180 °, the current value of the drive current is The generated torque T0 is set to 0. At this time, the magnet M1 on the rotor side is caused by the magnetic attractive force acting between the arms 5a, 5b of the armature core 5 of the stator St and the magnets M1, M2 formed of a magnetic material such as a rigid plate. , M2 magnetic pole centers (positions where the magnetic force is strongest) M1a and M2a try to stabilize in a state where they face the tips of the arm portions 5a and 5b of the armature core 5 extending in both side directions (X direction).
[0028]
That is, at the position where the rotation angle θ = 0 °, the magnets M1 and M2 are stopped facing the tips of the arm portions 5a and 5b of the armature core 5, so that the coils C1 and C2 on the stator St side Even when a drive current is applied, the first dead point (dead point) D1 at which the rotor R does not start is the same, and similarly, the position at the rotation angle θ = 180 ° is the second dead point D2.
[0029]
Next, the cogging torque generated in the two-phase motor will be described.
(1) Stator cogging torque (first cogging torque) Ts
When positioned at the first dead point (rotation angle θ = 0 °) D1, the magnetic pole centers M1a and M2a of the magnets M1 and M2 are opposed to the tips of the arm portions 5a and 5b of the armature core 5 and stopped. Therefore, as shown in FIG. 6, the stator cogging torque Ts acting between the armature core 5 of the stator St and the magnets M1, M2 is zero.
[0030]
From the first dead point D1, when the rotor R is not energized without applying drive current to the coils C1 and C2, that is, when the rotor R is manually rotated, for example, counterclockwise, the rotor R is returned to the original first point D1. The force to return to the position of the dead point D1 is applied. That is, the rotor R has the magnetic attraction force that attempts to return the magnetic pole center M1a of the magnet M1 to a stable position facing one arm portion 5a of the armature core 5, and the magnetic pole center M2a of the magnet M2. The magnetic attraction force that attempts to return to the stable position facing the other arm portion 5b of the child core 5 starts to act simultaneously in the clockwise direction as the stator cogging torque Ts (see FIG. 4). In FIG. 6, the stator cogging torque Ts acting in the clockwise direction is shown as positive torque, and the stator cogging torque Ts acting in the counterclockwise direction is shown as negative torque.
[0031]
Further, when the rotor R is rotated counterclockwise and the rotation angle θ of the rotor R reaches θ = 90 ° (state of FIG. 3), the magnetic attraction force between the magnets M1 and M2 and the arm portion 5a, Since the magnetic attractive force with the arm portion 5b cancels out, the stator cogging torque Ts becomes zero as shown in FIG.
[0032]
When the rotor R is further rotated and the rotation angle θ exceeds θ = 90 °, the magnetic pole center M1a of the magnet M1 is magnetically attracted to the arm portion 5b of the armature core 5 located on the opposite side, and the magnetic pole of the magnet M2 Since the center M2a is magnetically attracted to the arm portion 5a of the armature core 5 located on the opposite side, the rotor R is accelerated in the counterclockwise direction until the rotation angle θ reaches 180 °. Therefore, as shown in FIG. 6, the stator cogging torque Ts acts to promote the rotation of the rotor R in the counterclockwise direction when the rotation angle θ is in the range of 90 ° <θ <180 °. As shown.
[0033]
At the second dead point D2 where the rotation angle θ of the rotor R is θ = 180 °, the magnetic pole center M1a of the magnet M1 is magnetically attracted to the arm portion 5b of the armature core 5, and the magnetic pole center M2a of the magnet M2 is armature. Since it is magnetically attracted to the arm portion 5a of the core 5, the rotation of the rotor R is brought into a stable state. Therefore, as shown in FIG. 6, when the rotation angle θ is 180 °, the stator cogging torque Ts acting on the rotor R becomes zero.
[0034]
If the rotor R is further rotated counterclockwise from this state, a force for returning the rotor R to the position of the second dead point D2 acts on the magnets M1 and M2 in the clockwise direction. As in the range of 0 ° <θ <90 °, the stator cogging torque Ts turns positive. Further, when the rotor R is further rotated counterclockwise and the rotation angle θ is in the range of 270 ° <θ <360 °, the rotor R is accelerated counterclockwise, so that the stator cogging torque Ts Turns negative.
[0035]
Thus, the stator cogging torque Ts changes with an approximate curve along sin 2θ.
[0036]
(2) Plate cogging torque (second cogging torque) Tp
On the other hand, as described above, a magnetic attractive force is also acting between the plates 8a and 8b in the two-phase motor 1 and the magnets M1 and M2. Therefore, a plate cogging torque (second cogging torque) Tp similar to the stator cogging torque Ts is generated between the plates 8a and 8b and the rotor R.
[0037]
However, the plates 8a and 8b are provided at positions shifted counterclockwise by the attachment angle α. Therefore, at the first dead point (state shown in FIG. 1) D1 where the rotation angle θ of the rotor R is 0 °, the magnet M1 is magnetically attracted to the plate 8a, and the magnet M2 is magnetically attracted to the plate 8b. Therefore, as shown in FIG. 6, a negative plate cogging torque Tp that rotates the rotor R counterclockwise acts at a position where the rotation angle θ = 0 °.
[0038]
Similarly to the above, when the motor is rotated counterclockwise and the position shown in FIG. 4A, that is, the rotation angle θ of the rotor R coincides with the mounting angle α of the plates 8a and 8b (θ = α), the magnets M1 and M2 Since the magnetic pole centers M1a and M2a of the plate face the centers of the plates 8a and 8b, the plate cogging torque Tp becomes zero.
[0039]
Further, when the rotor R is rotated counterclockwise and the rotation angle θ passes the attachment angle α, the magnetic attraction force that attempts to return the rotor R to the state shown in FIG. 4A becomes the plate cogging torque Tp in the clockwise direction. Therefore, the plate cogging torque Tp turns to positive. In such a state, the rotation angle θ acts in the range of α <θ <α + 90 °.
[0040]
When the rotation angle θ of the rotor R coincides with θ = α + 90 °, the magnetic pole centers M1a and M2a of the magnets M1 and M2 are positioned at an equal distance from the plates 8a and 8b as shown in FIG. 4B. , 8b, the magnetic attractive forces from the magnets M1, M2 cancel each other. Therefore, at this time, the plate cogging torque Tp becomes zero.
[0041]
  Further, when the rotor R is rotated counterclockwise and the rotation angle θ exceeds θ = α + 90 °, the magnet M1 is magnetically attracted to the plate 8b, and the magnet M2 is magnetically attracted to the plate 8a and tries to stabilize. Rotor R counterclockwiserotationA negative plate cogging torque Tp is applied. In this state, the rotation angle θ acts in the range of 90 ° <θ <α + 180 °.
[0042]
When the rotor R is further rotated counterclockwise and the rotation angle θ coincides with θ = α + 180 ° as shown in FIG. 4C, the magnetic pole center M1a of the magnet M1 faces the center of the plate 8b, and the magnetic pole center of the magnet M2 Since M2a faces the center of the plate 8a, the plate cogging torque Tp becomes zero.
[0043]
  Further, when the rotor R is rotated counterclockwise and the rotation angle θ exceeds θ = α + 180 °, the magnet M1 is magnetically attracted to the plate 8b, and the magnet M2 is magnetically attracted to the plate 8a to attempt to stabilize. In the clockwise direction on the rotor RrotationA positive plate cogging torque Tp is applied. In this state, the rotation angle θ acts in the range of 180 ° <θ <α + 270 °.
[0044]
When the rotation angle θ of the rotor R coincides with θ = α + 270 °, that is, as shown in FIG. 4D, the magnetic pole centers M1a and M2a of the magnets M1 and M2 are positioned at equal distances from the plates 8a and 8b. Become. Accordingly, similarly to the above, the magnetic attraction force from the magnets M1 and M2 acting on the plates 8a and 8b cancel each other, so that the plate cogging torque Tp becomes zero.
[0045]
When the rotation angle θ of the rotor R is in the range of α + 270 ° <θ <360 ° = 0 ° (first dead point D1), the magnet M1 is magnetically attracted to the plate 8a, and the magnet M2 is magnetically attracted to the plate 8b. In order to stabilize the rotor, a negative plate cogging torque Tp acting counterclockwise acts on the rotor R.
[0046]
That is, the plate cogging torque Tp generated when the rotor R rotates once changes with an approximate curve along sin (2θ + α) as shown in FIG.
[0047]
Thus, if the two-phase motor 1 is provided with the plates 8a and 8b, two types of cogging torque can be applied between the rotor R of the two-phase motor 1 and the stator St. For this reason, the total cogging torque acting between the rotor R and the stator St is (Ts + Tp) obtained by vector-combining the stator cogging torque Ts and the plate cogging torque Tp. In FIG. This is shown as torque Tc.
[0048]
That is, when the non-energized rotor R is rotated counterclockwise or clockwise, the combined cogging torque Tc (= Ts + Tp) acts between the rotor R and the stator St.
[0049]
Next, when the two-phase motor 1 is energized and a sinusoidal drive current is applied to the coils C1 and C2, as shown in FIG. 7, the rotational torque T acting on the two-phase motor is the generated torque T0 and the generated torque T0. The resultant force is the combined cogging torque Tc.
[0050]
When the plates 8a and 8b are not provided, only the stator cogging coil (first cogging coil) Ts acts. In this case, the first dead point D1 and the second dead point D2 ( 5) coincides with the zero cross points (see FIG. 6) P1 and P2 at which the magnitude of the stator cogging torque Ts becomes zero, so that the two-phase motor 1 cannot be started.
[0051]
However, when the plates 8a and 8b are provided, as shown in FIG. 7, the phase of the combined cogging torque Tc is shifted, so that the first dead point D1 and the second dead point D2 and the combined cogging torque Tc The zero cross point does not match.
[0052]
That is, the stop positions of the magnets M1 and M2 when the rotation of the rotor R is stopped are not the positions where the magnetic centers M1a and M2a of the magnets M1 and M2 face the tips of the armature cores 5a and 5b (see FIG. 1). It is possible to set the position shifted in the counterclockwise direction in the figure.
[0053]
Therefore, it is possible to reliably start the rotor R by applying a drive current to the coils C1 and C2 and generating a generated torque in the stator St.
[0054]
Here, the total torque of the rotor R rotated in the clockwise direction can be represented by a rotational torque T obtained by combining the generated torque T0 and the combined cogging torque Tc as shown in FIG.
[0055]
In the example shown in FIG. 7, when the area surrounded by the curve of the rotational torque T and the straight line with the torque of 0 (0 [μN · m]) is compared between the plus side and the minus side of the torque, it is compared with the area on the minus side. The area on the plus side is larger. That is, the component that rotates the rotor R in the forward direction, which is clockwise, is larger than the reverse component that prevents the rotation of the rotor. Therefore, the rotor R is driven to rotate in the clockwise direction. However, since the torque on the minus side is so large that it cannot be ignored compared to the plus side, it is difficult to keep the motor rotating smoothly.
[0056]
Therefore, as shown in FIG. 8, when the direction of the drive current output from the motor driver 12 is switched every 180 ° by providing a signal switching means in the drive signal generator 11, the rotational torque T Since the area on the minus side can be reduced, the two-phase motor 1 can be smoothly rotated.
[0057]
Even if the direction of the drive current is changed as described above, a slight rotational torque T remains on the minus side, but since the motor has already been sufficiently accelerated, the minus side rotational torque T Without being stopped, it can be smoothly accelerated by receiving the rotational torque T on the plus side.
[0058]
As described above, in the above embodiment, the cogging torque, which has been conventionally unnecessary, is combined with the generated torque of the motor, so that it can be effectively used as the rotational torque for promoting the rotation.
[0059]
In addition, the area of the rotational torque T can be increased by synthesizing, and a sufficiently large torque can be generated compared to the conventional case. Therefore, even an outer rotor type motor having a large moment of inertia can be rotated at a sufficient rotational speed without decelerating the rotor.
[0060]
In the above description, when the mounting position α of the plates 8a and 8b is brought closer to 0 °, the plates 8a and 8b overlap the tip of the armature core 5, and thus the functions of the plates 8a and 8b are lost. Further, when the attachment position α is 90 °, the stator cogging torque Ts becomes 0 as shown in FIG. 6, so that the combined cogging torque Tc becomes small and a sufficiently large rotational torque T cannot be generated. Therefore, a preferable mounting position of the plates 8a and 8b is such that the mounting angle α from the X axis is in the range of 0 ° <α <90 °, and more preferably in the range of 60 ° ≦ α ≦ 80 °.
[0061]
The direction of the drive current may be switched every 180 °, which is the half cycle of the sine wave as described above. However, if the switching is performed at a timing earlier than 180 °, the rotation torque T is further decreased. Since the area on the side can be reduced, it is possible to obtain a larger rotational torque than before.
[0062]
In the above embodiment, the plate 8a, 8b is provided in the space between the rotor R and the stator St. However, the present invention is not limited to this, and for example, reference numeral 9a in FIG. , 9b and a dotted line, the rotor R may be provided at a position outside the frame 3 so as to face the mignets M1 and M2 in the frame 3.
[0063]
In the above description, the outer rotor type two-phase motor in which the rotor provided with the magnets M1 and M2 in the frame 3 rotates has been described. However, the inner rotor type two-phase motor in which the armature core side rotates is also described. Also good.
[0065]
【The invention's effect】
As described above, according to the present invention, the rotation of the rotor can be stopped at a position where the magnet and the armature do not face each other, so that the rotor can be reliably started.
[0066]
Further, since it is possible to use the cogging torque that has been conventionally unnecessary, a large rotational torque can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a two-phase motor as an embodiment of the present invention;
FIG. 2 is a longitudinal sectional view taken along line II-II in FIG.
FIG. 3 is a cross-sectional view of a two-phase motor similar to FIG. 1, with the rotor rotated 90 degrees counterclockwise;
4 is a cross-sectional view of a two-phase motor similar to FIG. 1, where A is a state in which the rotor is rotated by a rotation angle α, B is a state in which the rotor is rotated by a rotation angle α + 90 °, and C is a rotation of the rotor. The state where the angle α + 180 ° is rotated, D is the state where the rotor is rotated the rotation angle α + 270 °,
FIG. 5 is a graph showing generated torque generated only by the interaction between the magnetic flux generated by the drive current flowing in the coil of the stator St and the rotor magnet;
FIG. 6 is a graph showing cogging torque generated in the rotor for each rotation angle of the rotor;
FIG. 7 is a graph showing a composition of torque generated in the two-phase motor when the direction of the drive current is not switched;
FIG. 8 is a graph showing rotational torque generated in a two-phase motor when the direction of drive current is switched every half cycle (180 °);
[Explanation of symbols]
1 Two-phase motor
2 Rotating shaft
3 Frame
5 Armature core 5
5a, 5b Arm
8a, 8b plate
C1, C2 coil
D1, D2 dead point
M1, M2 magnet
P1, P2 Zero cross point
R rotor
St stator
α Mounting angle
θ rotation angle
T Rotational torque
Tc Synthetic cogging torque
Ts Stator cogging torque (first cogging torque)
Tp Plate cogging torque (second cogging torque)

Claims (3)

A rotor that rotates together with the rotating shaft, and a stator that is a fixed side;
One of the rotor and the stator has a pair of magnetic arm portions arranged in a direction orthogonal to the rotation axis and at an angle of 180 degrees with each other, a coil wound around each arm portion, and a magnetic material A pair of magnetic members formed of
The other of the rotor and the stator is provided with two magnets facing the tip of the arm part, and the two magnets have different magnetic poles on the magnetized surface facing the arm part and two magnets. Each of the magnetized surfaces is formed in a range of 180 degrees toward the rotation direction of the rotor,
The centers of the respective arm portions and the centers of the respective magnetic members are arranged at an angle α in the rotation direction of the rotor, and the angle α is not less than 60 degrees and not more than 80 degrees. Two-phase motor. The two-phase motor according to claim 1 , wherein the angle α is 75 degrees . It said coil driving means for providing a driving current varying sine wave is provided, in the said drive means, according to claim direction of the drive current, that every half cycle of a sine wave, or is switched at a timing earlier than The two-phase motor according to 1 or 2 .

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