JPH0623188Y2 - Variable air gap motor device - Google Patents

Description

Detailed Description of the Invention A. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable air gap motor device, which is intended to efficiently obtain low speed and high torque output.

B. SUMMARY OF THE INVENTION The present invention detects the revolution position of a rotor of a variable air gap motor and excites a stator coil so that maximum torque is obtained at each revolution position to generate electromagnetic absorption force and electromagnetic repulsion force. This increases the output trick.

C. 2. Description of the Related Art 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 driving device for such a robot,
A low-speed, 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 at present have a fixed gap type with a fixed gap between the rotor and the stator, 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. 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 slowly, while the rotor itself slowly rotates in the direction opposite 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 air gap motor will now be described with reference to the drawings. As shown in FIG. 4, a rotor 2 made of a magnetic material is arranged in 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 of 6 pairs coils _{C 1, C 2, C 3} , C 4, C 5, C ₆ are provided, the coils _{C 1, C 2, C 3} , C 4, C 5, C
Reference numeral ₆ is connected to a three-phase commercial power source via diodes D ₁ , D ₂ , D ₃ , D ₄ , D ₅ , and D ₆ . Therefore, when the phase is t ₀ in FIG. 5, current flows through the coils C ₆ , C ₁ , C ₂ and does not flow through the coils C ₃ , C ₄ , C ₅ . Therefore, the rotor 2 is affected by electromagnetic force in the coils C ₆ , C of the stator 1.
₁ and C ₂ are sucked. 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 has an arrow II
While revolving in the direction, it rotates in the direction opposite to the revolving 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 view of FIG. 6, rotor 2 (its radius r)
Moves along the stator 1 (its radius R), the locus of the center of the rotor 2 is a circle having a radius (R-r) and 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 times 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 Torque of Variable Air Gap Motor: The torque generated when the magnetic pole P ₁ is excited at the rotor position in FIG. 7 is calculated. FIG. 8 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. 8, the tangential force F _r acting on the rotor is given by the following equation from the similar relationship of the triangles in FIG.

F becomes the following formula.

l is from FIG. 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 the equations (4) and (5), The revolution force T ₁ is calculated from the above formula 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 Although the variable air gap motor has the above-described structure, action, and characteristics, the driving of such a motor generates an electromagnetic attraction force due to magnetization to generate torque. That is, the rotor is driven by exciting the coils of the stator at the rotor contact position and the position preceding the rotor position in the revolution direction, and the coils that contribute to the torque generation are large in number, and the half circumference that precedes the revolution direction. Only the minute coil is used. Therefore, the coil for a half turn in the direction opposite to the revolution direction of the rotor is at rest. Specifically, as described with reference to FIG. 4, for example, the coils C ₆ , C ₁ ,
C ₂ is as that will be energized without coil _{C 3,} C 4, _{C 5} is energized.

In view of the above-mentioned conventional technique, the present invention provides a variable air gap motor device that drives a rotor by using a coil of the entire circumference to generate higher torque.

E. Means and Actions for Solving Problems In the present invention for solving the above problems, the rotor surface is magnetized alternately in the circumferential direction in the NS direction, and the stator coil is attracted and repelled to the magnetized state on the rotor surface. In order to drive the rotor, an attracting force is generated in a coil in contact with the rotor and a coil in the revolution direction of the rotor, and a repulsive force is generated in a direction opposite to the revolution direction.

F. Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 shows a variable air gap motor 10 used in the embodiment, in which a stator 11 formed of a magnetic material, for example, a cylindrical rotor 12 is arranged. Numerous coils _C in the stator _{11 0, C 1, C 2} , C 3, C 4, ... C n-1, C n is installed, each coil _C 0 -C _n independently excited An electric current is passed. Pole _P 0 is energized the coils _{C 0 ~C n, P 1,} P 2, P 3, ... P n-1, Pn are magnetized, the magnetic pole appears N pole or S pole.

On the other hand, the rotor 12 is magnetized alternately in the N and S directions along the circumferential direction. This magnetization is performed by previously attaching a permanent magnet to the rotor 12 or by using the rotor 12 itself as a permanent magnet, but an electromagnet may be attached to the rotor 12 along the circumferential direction for magnetization.

Further, the rotor 12 is adjusted to match the intervals of the magnetic poles P _{1 to} P _n of the stator 11, in other words, N and S of the magnetic poles of the stator 11.
So that the magnets N and S of the rotor 12 face each other and coincide with each other.
Although it is preferable to magnetize the rotor 12, when a plurality of adjacent magnetic poles of the stator 11 are collectively magnetized to the same pole at the same time, it is preferable to magnetize the rotor 12 according to the magnetized state of the stator 11.

When the rotor 12 is driven by setting two or more magnetized states of the stator 11, the rotor 1 may be adapted to all the magnetized states depending on the combination of these magnetized states.
It is also possible to magnetize 2. In short, at the suction position, N
In the position where S is repulsive, the rotor 12 may be magnetized so that NN or SS can face each other.

By magnetizing the rotor 12 in this manner, not only the attraction force higher than the conventional force is generated between the rotor 12 and the magnetic poles of the stator 11, but also the repulsion force is generated. That is, the magnetic poles P ₁ , P ₂ , P _3, ... Of the stator 11 are magnetized so as to attract the magnets of the rotor 12 from the contact position P ₀ between the rotor 12 and the stator 11 in the revolution traveling direction (direction II in FIG. 1). At the same time, in the direction opposite to the direction of revolution,
The magnetic poles _Pn , _Pn-1 , _Pn-2, ... Of the stator 11 are magnetized to have the same poles that repel the magnets of the rotor 12. In this way, the rotor 12 revolves in the direction of arrow II while rotating in the direction of arrow by the attraction force and the repulsive force.
Then, as the mechanical output, the low-speed rotation of the rotor 12 is taken out.

FIG. 2 shows an embodiment including a control system using the variable air gap motor 10 described above. In the figure, the position detector 20
Is formed by a resolver or the like and 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 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, a specific coil energized to maximize electromagnetic attraction of the rotor 12 at the revolution position and a ratio of voltage values applied to each coil. It is stored as an excitation pattern, and a specific coil that energizes so that the rotor 12 is repulsed to the maximum and a ratio of voltage values applied to each coil are stored as a coil excitation pattern.

For example, the revolution position shown in FIG. 1, that is, the rotor 12 has the magnetic pole P.
_{When in contact with 0} , the coils C ₀ , C ₁ , C ₂ , C
_{3, C} 4, _{C 5} that coil _C 0 and the current for the suction _{to, 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: 0.2 and the coils P _n , P
_n-1 and P _n-2 are energized for repulsion and the coil C
The ratio of the voltage values applied to _n , C _n-1 and C _n-2 is C _n :
The pattern is stored such that C _n-1 : C _n-2 = 0.2: 0.8: 0.4. On the other hand, the address translator 32
The revolution position signal a is converted into an address, and the read address b indicating the address on the memory 31 storing the coil excitation pattern of this revolution position is output. 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 (the coil C at the revolution position in FIG. ₁₎ indicating the specific coil to be excited.
₀ , C ₁ , C ₂ , C ₃ , C ₄ , C ₅ and C _n ,
C _n−1 , C _n−2 ) and voltage value ratio information d ₂ indicating the ratio of the applied voltage value of each coil (C ₀ : C ₁ : in this embodiment).
_{C 2: C 3: C 4} : C 5 = 0.2: 0.4: 0.8: 1.0: 0.4:
0.2 and _{C n: C n-1:} C n-2 = 0.2: 0.8: will have a 0.4).

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 magnitude of the load on the variable air gap motor 10. Then, the multiplier 40 multiplies the voltage value ratio information d ₂ by the torque command t. When the value of the torque command t is 3, for example, the multiplication voltage 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: 0.6, C _n :
Cn _-1 : Cn _-2 = 0.6: 2.4: 1.2. 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 voltage value ratio information d ₂ ′.

The driver circuit 50 includes transistors T _r0 , T _r1 , T
_{r2 ... T rn-1, T} rn and (partially shown), a comparator _{CP 0,} CP _1, CP and _{2 ... CP n-1, CP} n ( partially shown), a DC power source 51 and triangular wave generator And 52. When the drive transistors T _{r0 to} T _rn are turned on, the coils of the variable air gap motor 10 having the same suffix are individually fed. When the multiplication excitation command d'is input to the driver circuit 50, the transistor that supplies power to the coil indicated by the specific coil information d ₁ is activated, and each transistor T in the activated state is activated.
PWM (pulse frequency modulation) control is performed so that the ratio of the average value of the output voltage of _r becomes that shown by the multiplication voltage value ratio information d ₂ ′.

Here, this PWM control will be described with reference to FIG. 2 and FIG. The triangular wave generator 52 outputs a triangular wave signal E as shown in FIG. Therefore, when the level of the multiplication voltage value ratio information d ₂ ′ is L ₁ , the comparator output F of the comparator CP is as shown in FIG. 3 (b), and when the level is L ₂ , the comparator output F is shown in FIG. c) and when the level is L ₃ , the comparator output F becomes the third
It looks like Figure (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, depending on the level of the multiplied voltage value ratio information d ₂ ′, the transistor _Tr
The ON time is determined and the PWM control is performed.

Therefore, when in the revolution position of FIG. 1, the transistors T _r0 , T _r1 , T _r2 , T _r3 , T _r4 , and T _r0 .
_The coils C ₀ , C ₁ , C ₂ , C ₃ , C ₄ , C ₅ and C _n , by _r5 and T _rn , T _rn-1 , T _rn-2 ,
Power is supplied to C _n-1 and C _n-2 . For example, when the value of the torque command t is 3, the ratio of the average value of the voltage is tripled to 0.
It looks like 6: 1.2: 2.4: 3.0: 1.2: 0.6 and 0.6: 2.4: 1.2. Thus, the rotor 12 rotates (spins and revolves) due to not only the attractive force but also the repulsive force at each revolution position.

G. Effect of the Invention As described above, according to the present invention, the rotor can be moved by the suction force and the repulsive force, and the output torque can be greatly increased.

[Brief description of drawings]

1 to 3 show one embodiment of the present invention. FIG. 1 is a block diagram of a variable air gap motor, FIG. 2 is a control circuit diagram, FIG. 3 is a PWM control waveform diagram, and FIGS. Figure 8 is a conventional example,
FIG. 4 is a block diagram of a variable air gap motor, and FIG. 5 is a U.V. V. W. FIG. 6 is a waveform diagram of each phase, FIG. 6 is an explanatory diagram showing the movement of the variable air gap motor, and FIGS. 7 and 8 are explanatory diagrams for calculating the torque, respectively. In the figure, 11 is a stator, 12 is a rotor, P _{0 to} P _n are magnetic poles of the stator, and C _{1 to} C _n are coils of the stator.

Claims (1)

[Scope of utility model registration request] 1. A stator comprising a large number of independent coils, which 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. A variable air gap motor having a rotor that revolves in the direction opposite to the rotation along the circumferential direction of the stator, and a position detector that detects the revolution position of the rotor of the variable air gap motor and outputs a revolution position signal. In the air gap motor device, the surface of the rotor is magnetized alternately in the circumferential direction in the NS direction according to the magnetized state of the stator, and an electromagnetic wave is generated from a contact position to a required coil in the revolution advancing direction according to the revolution position of the magnetized rotor. A variable air gap motor device characterized in that it is magnetized so as to generate an attractive force and to generate an electromagnetic repulsive force in a required coil in a direction opposite to the revolution proceeding direction from the contact position.