JPH087839Y2 - Variable air gap motor device - Google Patents

Description

[Detailed description of the device] A. Industrial field of application
It is intended to obtain a high torque output.

B. Outline of the Invention The present invention detects the revolution position of the rotor of the variable air gap motor and excites the stator coil so that the maximum torque is obtained at each revolution position, so that the rotor is always synchronized with the coil excitation position. It is a variable air gap motor device that allows it to rotate without "slip".

C. Conventional Technology Robots have become popular in recent years. The robot is required to move as accurately and as complicatedly as a human arm or hand. As a drive device for such a robot or the like, one that can obtain a low speed and high torque output is used.

Currently, as a device for obtaining a low speed / high torque output, there is a gear motor drive device in which an ordinary motor and a reduction gear are combined. However, in this gear motor driving device, it is difficult to reduce the size because the motor and the gear are combined, and there is a limit to the improvement in accuracy due to the backlash of the reduction gear.

Another device that obtains low-speed and high-torque output is a variable air gap motor that was previously developed. Motors that are commonly used today are of the fixed air gap type in which the gap between the rotor and the stator is constant, and an electric current is passed through the rotor coil located in the magnetic field to generate an electromagnetic force generated by Fleming's left-hand rule. Is output as. On the other hand, as will be described later in detail, in the variable air gap motor, the rotor rolls along the inner peripheral surface of the stator and revolves around the rotor, while the rotor itself slowly rotates in the opposite direction to the revolution direction, so that the rotor-stator gap changes. Further, the rotational force is generated when the coil of the stator serves as an electromagnet and attracts the rotor made of a magnetic material.

The variable gap rotor will now be described with reference to the drawings.
As shown in FIG. 5, a rotor 2 made of a magnetic material is arranged inside the stator 1. Both ends of the rotor 2 are supported by special bearings, and the rotor 2 rolls on the inner peripheral surface of the stator 1 in the direction of arrow I to rotate about its axis so that the rotor 2 can revolve in the direction of arrow II. The stator 1 is provided with six sets of coils C ₁ , C ₂ , C ₃ , C ₄ , C ₅ , C ₆ , and these coils C ₁ , C ₂ , C ₃ , C ₄ , C ₅ , C ₆ Is the diode D ₁ , D ₂ ,
It is connected to the three-phase commercial power supply via D ₃ , D ₄ , D ₅ , and D ₆ . Therefore, when the phase is t ₀ in FIG.
It flows into C ₆ , C ₁ and C ₂ and does not flow into coils C ₃ , C ₄ and C ₅ . For this reason, the rotor 2 is made to coil the stator 1 by the electromagnetic force.
Suctioned to the C ₆ , C ₁ , and C ₂ sides. Since such a suction state rotates with time, a rotary suction force is obtained, and its synchronous speed is the same as that of the three-phase two-pole winding. Thus the rotor 2 is an arrow
It revolves in the direction opposite to the revolving direction while revolving in the II direction. In this case, the smaller the difference between the inner diameter of the stator 1 and the diameter of the rotor 2, the smaller the rotation speed of the rotor 2, and the larger the ratio of the rotation speed to the revolution speed (reduction ratio).

Next, various characteristics of such a variable air gap motor will be described.

Regarding Cyclo Motion of Variable Air Gap Motor: As shown in the schematic diagram of FIG. 7, when the rotor 2 (its radius r) moves along with the stator 1 (its radius R), the center locus of the rotor 2 has a radius ( R-r) makes a circle concentric with the stator 1. When the rotor 2 rotates by n rotations, assuming that there is no slip between the rotor 2 and the stator 1, the center of the rotor 2 moves by 2πr · n. Further, the moving distance of the center of the rotor 2 when revolving only m rotations is 2π (R−r) ·
m. Since both are equal, 2πrn = 2π (R−r) m (1) Therefore, the speed ratio of revolution and rotation is as follows.

Since the power P is constant in the relationship between the revolution force T ₁ and the rotation force T ₂ , Becomes

Regarding the torque of the variable air gap motor: At the rotor position shown in FIG. 8, the torque generated when the magnetic pole P ₁ is excited is calculated. FIG. 9 is drawn with a large angle α in order to make the movement easy to understand. Assuming that the force F acts between the teeth and the rotor in FIG. 9, the tangential force F _r acting on the rotor is given by the following equation from the similar relationship of the triangles in the figure.

F becomes the following formula.

l is from Fig. 9 Substituting equations (5) and (6) into equation (4) The rotation torque T ₂ is Becomes

The torque is expressed based on the magnetic flux density as follows. The rotation force T ₂ = r · F _r , and by substituting equations (4) and (5), The revolution force T ₁ can be calculated from the above equation and (3). Becomes

From the above, it can be seen that the torque of the variable air gap motor is extremely large.

D. Problems to be Solved by the Invention In the conventional variable air gap motor, the rotor 2 rotates while slipping because it is driven by using the rotating magnetic field from the three-phase commercial power source. When such a slip occurs, it is difficult to improve the rotational position accuracy, and
The torque characteristics decrease with rotation as shown in Fig. 10, and the advantage of high torque characteristics is reduced. Further, the noise is increased due to the slip.

In view of the above-mentioned conventional technique, the present invention provides a variable air gap motor,
(EN) Provided is a variable air gap motor device which is free from slippage, has high output torque efficiency, and can be operated with high precision.

E. Means for Solving Problems The configuration of the present invention for solving the above problems is such that a magnetic material is provided in a stator in which a number of independent coils that generate an electromagnetic attraction force when energized are installed in the circumferential direction. The variable gap motor with the rotor that revolves in the direction opposite to the rotation along the circumferential direction of the stator by rolling on the inner peripheral surface of the stator and rotating around it, and the revolution position of the rotor of the variable gap motor. A position detector that detects and outputs a revolution position signal and a plurality of coils along the revolution direction of the rotor from the contact point where the rotor is in contact with the stator to maximize electromagnetic attraction of the rotor by the stator coil. The coil excitation patterns that are excited and that the exciting force of each coil increases stepwise from the contact point in the direction of revolution and then decreases stepwise, respectively, are the respective public shifts of the rotor. When the revolution position signal is input, a coil specified by the coil excitation pattern corresponding to the rotor revolution position at that time and an excitation command including the excitation value of each coil as information are output. The memory device and the excitation value of the excitation command input from the memory device are multiplied by the torque command input from the outside, and the multiplication including the multiplication excitation value obtained by the multiplication and the specific coil to be excited as information. A multiplier that outputs an excitation command, and a driver circuit that controls energization so that specific coils of the stator indicated by the multiplication excitation command input from the multiplier are individually excited according to the multiplication excitation value are provided. Characterize.

F. Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a variable air gap motor 10 used in the embodiment, in which a rotor 12 made of a magnetic material is arranged in a stator 11. In the stator 11, a large number of coils C ₀ , C ₁ , C ₂ , C ₃ ,
C ₄ , ... C _n-1 , C _n are installed, and current is independently applied to each coil C _{0 to} C _n . Pole P ₀ is energized the coils _{C 0 ~C n, P 1,} P 2, P 3, ... P n-1, P n sucks rotor 12 are magnetized. When the excited magnetic poles sequentially shift counterclockwise, the rotor 12 revolves in the direction of arrow II while rotating in the direction of arrow I. In this variable air gap rotor 10, the rotor 12
The rotation force of is taken out as an external output and applied to the load.

FIG. 2 shows a first embodiment using the variable air gap motor 10 described above. In the figure, the position detector 20 is formed of a resolver or the like, and is a rotor of the variable air gap motor 10.
The 12 revolution positions are detected and a revolution position signal a which is the detected value is output. The memory device 30 is composed of a memory (ROM) 31 and an address converter 32. The memory 31 stores, for each revolution position of the rotor 12, the rotor 12 at the revolution position.
Is stored as a coil excitation pattern, which is a specific coil to be energized to maximize electromagnetic attraction and a ratio of current values passed through the coils. For example, in the revolution position shown in FIG. 1, that is, when the rotor 12 is in contact with the magnetic pole P ₀ , the coils C ₀ , C ₁ , C ₂ , C ₃ , C ₄ and C ₅ are energized and the other coils are energized. Not flowing, and the coils C ₀ , C ₁ , C ₂ , C ₃ , C ₄ ,
The ratio of the currents flowing through C ₅ is C ₀ : C ₁ : C ₂ : C ₃ : C ₄ : C ₅ = 0.2: 0.
It is set to 4: 0.8: 1.0: 0.4: 0.2. Similar excitation patterns are stored even when the revolution position of the rotor 12 is deviated.
That is, only the six coils are energized forward from the magnetic poles in contact with the rotor 12 in the direction of revolution, and the ratio of the current values of the coils is 0.2: 0.4: 0.8: 1.0: in order from the one closer to the magnetic poles in contact.
It is set to 0.4: 0.2. On the other hand, address translator 3
2 converts the revolution position signal a into an address and outputs a read address b indicating an address on the memory 31 which stores the coil excitation pattern of this revolution position. When the read address b is input, the memory 31 reads the excitation pattern of the address indicated by the read address b and outputs the excitation command d. Therefore, the excitation command d is the specific coil information d ₁ indicating the specific coil to be excited (the coil C ₀ ,
_{C 1, C 2, C 3} , C 4, C 5) and the current value ratio indicating the ratio of the current values of the respective coil Information d ₂ (in this example _{C 0: C 1: C 2} : C 3: C 4 : C ₅
= 0.2: 0.4: 0.8: 1.0: 0.4: 0.2).

The excitation command d and the torque command t are input to the multiplier 40. The value of the torque command t increases or decreases according to the load of the variable air gap motor 10. Then, the multiplier 40 multiplies the current value ratio information d ₂ by the torque command t. When the value of the torque command t is 3, in the present embodiment, the multiplication current value ratio information
d ₂ ′ is C ₀ : C ₁ : C ₂ : C ₃ : C ₄ : C ₅ = 0.6: 1.2: 2.4: 3.0: 1.2:
It becomes 0.6. Then, the multiplier 40 outputs the multiplication excitation command d ′ including the specific coil information d ₁ indicating the specific coil to be excited and the multiplication current value ratio information d ₂ ′.

The driver circuit 50 includes amplifiers A ₀ , A ₁ , A ₂ , ... A _n-1 , A
_n (only a part is shown) and current detectors CT ₀ , CT ₁ , C
T ₂ , ... CT _n-1 , CT _n (some figures are shown) and DC power supply 51
And have. Each amplifier A ₀ -A _n is a variable air gap motor 10
The currents are individually supplied to the coils C _{0 to} C _n having the same subscript. When the multiplication excitation command d'is input to the driver circuit 50, the amplifier energizing the coil indicated by the specific coil information d ₁ is in the operating state, and the ratio of the output current value of each amplifier in the operating state is the multiplication current. Feedback control is performed so that the value ratio information is as indicated by d ₂ ′. Therefore, in the revolution position shown in FIG. 1, the amplifiers A ₀ , A ₁ ,
When the coils C ₀ , C ₁ , C ₂ , C ₃ , C ₄ , C ₅ are energized by A ₂ , A ₃ , A ₄ , A ₅ , and the value of the torque command t is “3”, each current The ratio of is 0.6: 1.2: 2.4: 3.0: 1.2: 0.6 in order from C ₀ . Thus, at each revolution position, the rotor 12 is attracted and rotates (rotates and revolves) in the direction in which the maximum electromagnetic attraction force is generated without slipping. In the present embodiment, the ratio of the current values flowing in the coils C ₀ , C ₁ , C ₂ , C ₃ , C ₄ , C ₅ (coil excitation pattern) is C ₀ : C ₁ : C ₂ : C ₃ : C ₄ : C ₅ = 0.2: 0.
4: 0.8: 1.0: 0.4: 0.2, coil C ₀ ~ C _{5 of} stator 11
However, the coil excitation pattern is not limited to the above example. The point is that the excitation patterns of the plurality of coils along the revolution direction of the rotor 12 from the contact point where the rotor 12 is in contact with the stator 11 increase stepwise as the contact point advances in the revolution direction, and then decrease stepwise. It should be.

The rate of gradual increase and the rate of gradual decrease are
Determine according to the characteristics of each motor. Since the excitation pattern can be determined by the motor characteristics in this way, the operation can be performed so as to generate the maximum torque.

Note that if the excitation pattern is determined according to a prescribed function (linear equation, quadratic equation, sine function), maximum torque cannot be generated according to the motor characteristics.

FIG. 3 shows a second embodiment using the variable air gap motor 10 described above. In the figure, a position detector 120, which is formed by a resolver or the like, detects the revolution position of the rotor 12 of the variable air gap motor 10 and outputs a revolution position signal A which is the detected value. The memory device 130 is composed of a memory (ROM) 131 and an address converter 132. In the memory 131, for each revolution position of the rotor 12, a specific coil that is energized to maximize the electromagnetic attraction of the rotor 12 at the revolution position and the ratio of the voltage value applied to each coil are stored in the coil. It is stored as an excitation pattern. For example, when the rotor 12 is in contact with the magnetic pole P ₀ in the revolution position shown in FIG. 1, the coils C ₀ , C ₁ , C ₂ , C ₃ , C ₄ , C ₅ are energized and the other coils are energized. And the coils C ₀ , C ₁ ,
_{C 2, C 3, C 4} , C ratio of voltage applied to _{5 C 0: C 1: C 2} :
_{C 3: C 4: C 5} = 0.2: 0.4: 0.8: 1.0: 0.4: is 0.2. Similar excitation patterns are stored even when the revolution position of the rotor 12 is deviated. In other words, from the magnetic poles that the rotor 12 is in contact with, only six coils are energized along the front in the direction of revolution,
The ratio of the applied voltage value of each coil is set to 0.2: 0.4: 0.8: 1.0: 0.4: 0.2 in order from the one closer to the contacted magnetic pole. On the other hand, the address converter 132 converts the revolution position signal A into an address and outputs a read address B indicating an address on the memory 131 which stores the coil excitation pattern of this revolution position. When the read address B is input, the memory 131 reads the excitation pattern at the address indicated by the read address B and outputs the excitation command D. Therefore, excitation command D
Is the specific coil information D indicating the specific coil to be excited.
₁ (coils C ₀ , C ₁ , C ₂ , C ₃ , C ₄ , C at the revolution position in Fig. ₁ )
₅ ) and voltage value ratio information d ₂ that indicates the ratio of the voltage applied to each coil
(In this example _{C 0: C 1: C 2} : C 3: C 4: C 5 = 0.2: 0.4: 0.
8: 1.0: 0.4: 0.2).

The excitation command D and the torque command T are input to the multiplier 140. The value of the torque command T increases / decreases according to the magnitude of the load on the variable air gap motor 10. Then, the multiplier 140 multiplies the voltage value ratio information D ₂ by the torque command T. Torque command T
When the value of 3 can be 3, the multiplication voltage value ratio information D ₂ ′ in this embodiment is C ₀ : C ₁ : C ₂ : C ₃ : C ₄ : C ₅ = 0.6: 1.2: 2.4: 3.
It will be 0: 1.2: 0.6. Then, the multiplier 140 determines the specific coil information D ₂ indicating the specific coil to be excited and the multiplication voltage value ratio information.
The multiplication excitation command D'including D ₂ 'is output.

The driver circuit 150 includes transistors Tr ₀ , Tr ₁ , Tr ₂ , ...
Tr _n-1 , Tr _n (only part of which is shown) and comparators CP ₀ , CP ₁ , C
It has P ₂ , ... CP _n-1 , CP _n (only a part is shown), a DC power supply 151 and a triangular wave generator 152. When the drive transistors Tr _{0 to} Tr _n become conductive, the variable air gap motor
Of the 10 coils, the ones with the same suffix are individually fed. When the multiplication excitation command D'is input to the driver circuit 150, the transistor that supplies power to the coil indicated by the specific coil information D ₁ is activated, and the ratio of the average value of the output voltage of each transistor Tr in the activated state is Is subjected to PWM (pulse frequency modulation) control so that it becomes as shown by the multiplication voltage value ratio information D ₂ ′.

Here, this PWM control will be described with reference to FIG. 3 and FIG. The triangular wave generator 152 outputs a triangular wave signal E as shown in FIG. Therefore, if the level of the multiplication voltage value ratio information D ₂ ′ is L ₁ , the comparator output F of the comparator CP becomes as shown in FIG. 4 (b), and the level is L ₂
The comparator output F as it looks like FIG. 4 (c), there the comparator output F level L ₃ is as Fig. 4 (d). The transistor Tr becomes conductive only when the comparator output F is at high level, and supplies power to the coil C of the variable air gap motor 10. Therefore, the ON time of the transistor Tr is determined according to the level of the multiplication voltage value ratio information D ₂ ′, and the PWM control is performed.

Thus when in the revolving position of the first figure, transistors _{Tr 0, Tr 1, Tr 2} , Tr 3, Tr 4, Tr coils C ₀ by _5,
When power is supplied to C ₁ , C ₂ , C ₃ , C ₄ , and C ₅ and the value of the torque command T is “3”, the ratio of the average value of each voltage is _{0 in} order from C 0.
It will be 6: 1.2: 2.4: 3.0: 1.2: 0.6. Thus, at each revolution position, the rotor 12 is attracted and rotates (rotates and revolves) in the direction in which the maximum electromagnetic attraction force is generated without slipping.

G. Effect of the Invention According to the present invention as described based on the above-mentioned embodiment,
It has the following effects.

(A) The output torque is large because the stator coil is excited so that the electromagnetic attraction of the rotor is maximized.

(B) Since the rotor always rotates in synchronization with the rotation attracting magnetic field, the rotation position accuracy is improved and the rotation position accuracy is improved.

(D) Since it can be rotationally driven without slippage, the advantage of the variable air gap motor that the torque is large can be maximized by utilizing the electromagnetic attraction force.

(E) Since there is no slip, noise is reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a variable air gap motor used in an embodiment of the present invention, FIG. 2 is a circuit diagram showing a first embodiment of the present invention, and FIG. 3 is a second embodiment of the present invention. Circuit diagram shown, fourth
FIG. 5 is a waveform diagram for explaining PWM control. FIG. 5 is a schematic configuration diagram showing a conventional variable gap motor. FIG. 6 is a waveform diagram showing a three-phase alternating current input to the conventional variable gap motor.
9 to 9 are explanatory views for explaining the characteristics of the variable air gap motor, and FIG. 10 is a characteristic diagram showing the torque characteristics of the conventional variable air gap motor. In the drawing, 10 is a variable air gap motor, 11 is a stator, 12 is a rotor, 20,1
20 is a position detector, 30 and 130 are memory devices, 40 and 140 are multipliers, 50 and 150 are driver circuits, C ₀ , C ₁ , C ₂ ... C _n are coils,
a and A are revolution position signals, d and D are excitation commands, t and T are torque commands, and d'and D'are multiplication excitation commands.

Claims (1)

[Scope of utility model registration request] 1. A stator, which is provided with a large number of independent coils that generate an electromagnetic attraction force when energized in a circumferential direction, is made of a magnetic material and rolls on the inner peripheral surface of the stator to rotate. The variable air gap motor has a rotor that revolves around the circumference of the stator in the opposite direction of rotation, a position detector that detects the revolution position of the rotor of the variable air gap motor, and outputs a revolution position signal, and a stator coil. In order to maximize the electromagnetic attraction of the rotor by the rotor, a plurality of coils are excited along the revolution direction of the rotor from the contact point where the rotor is in contact with the stator, and the exciting force of each coil advances from the contact point in the revolution direction. A coil excitation pattern that gradually increases and then gradually decreases is stored in advance for each revolution position of the rotor. Is input, a coil device specified by the coil excitation pattern corresponding to the rotor revolution position at that time and a memory device that outputs an excitation command including the excitation value of each coil as information, and the excitation command input from the memory device. Multiply the excitation value by the externally input torque command, and output the multiplication excitation command that contains the multiplication excitation value obtained by multiplication and the specific coil to be excited as information, and the input from the multiplier. A variable air gap motor device, comprising: a driver circuit that controls energization so that a specific coil of the stator indicated by the multiplication excitation command is individually excited according to the multiplication excitation value.