JPH01278254A - Variable air gap type motor - Google Patents

Abstract

PURPOSE:To reduce a backlash by exciting in a backlach presented by a phase difference to be associated with a rotor in different phase difference from its phase difference. CONSTITUTION:A variable air gap type motor has exciting windings 3a, 3b for generating independently revolving magnetic fields from two stators 2a, 2b along its inner peripheral circle, and rotors 5a, 5b made of permanent magnets or the like are so associated in the space as to be rotatable around it. An output shaft 1 is so disposed that its center coincides with the stators 2a, 2b, and rotatably supported by bearings 15a, 15b of a housing 14. Reversing mechanisms 12a, 12b and zero tooth difference gear mechanisms 13a, 13b are provided as transmitting means for transmitting the rotating motion to the shaft 1 between the rotors 5a and 5b. Thus, the motor is controlled to be excited by the windings 3a, 3b at 180 deg. of phase difference to always apply a tangential pressure to the engaging part of the teeth of the means.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a variable gap type motor that generates low speed and large torque.

(Prior Art) A variable gap type motor is a motor that generates a large torque at low speed using a magnetic attraction force and a deceleration mechanism, and is used as an actuator for driving the joints of robots. However, since it uses a speed reduction mechanism, it inevitably suffers from the same drawbacks that speed reducers have. For example, the problem of backlash is an unavoidable problem as long as gears are used in the speed reduction mechanism. On the other hand, with conventional variable gap type motors, there is a way to minimize backlash by configuring the speed reduction mechanism with friction drive (Oldham coupling, etc.) without using gears, but as a servo actuator,
Friction drives are undesirable because of their rough edges and poor durability.
In the end, we have no choice but to use gears that can be expected to provide reliable power transmission.

(Problems to be Solved by the Invention) As described above, when gears are conventionally used in a variable gap type speed reduction mechanism, there is a drawback that backlash occurs. It is an object of the present invention to overcome these drawbacks and provide a variable gap type motor that can sufficiently suppress backlash even when gears are used in the speed reduction mechanism.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a plurality of stators that generate a rotating magnetic field, a central axis of which is different from the stator, and an electromagnetic force generated by the rotating magnetic field to generate a central axis of the stator. Multiple rotors that revolve around each other and rotate at the same time, an output shaft that has the same central axis as the stator, a transmission means that transmits the rotor motion to the output shaft, and a phase difference when the rotors are assembled. This is a variable air gap type motor consisting of an excitation control means that excites the stator using a phase difference.

(Function) By adopting the above-mentioned configuration, a variable air gap type motor with less backlash can be created by excitation with a phase difference different from the backlash that always exists with a phase difference that can be incorporated into the rotor. will be realized.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side sectional view of a variable gap type motor showing an embodiment of the present invention. The two stators 2a, 2b each have excitation windings 3a, 3b that generate independent rotating magnetic fields along their inner circumferences, and the space inside the stators 2a, 2b is filled with soft magnetic material or radially Rotors 5a and 5b made of magnetized permanent magnets are installed so as to be able to revolve along the inner periphery of the stators 2a and 2b.

Incidentally, the phase difference between the rotor 5a and the rotor 5b is exactly 1.
806. The output shaft 1 is arranged so that its center axis coincides with the center axes of the stators 2a and 2b, and is rotatably supported by bearings 15a and 15b attached to the housing 14.

Between the rotor 5a and the rotor 5b, rolling mechanisms 12a and 12b and a zero-gear differential gear *Xaa are provided as transmission means for transmitting the revolution motion of the respective rotors 5a and 5b to the output shaft 1.

13b is provided. This rolling mechanism 12a.

12b is the internal tooth 10 formed on the gear portion 4;

It consists of external teeth 11a and llb formed on the gear parts 5a and 5b so as to mesh with each other.In this embodiment, the number of internal teeth 10 is an even number and the external tooth 11a.

The number of teeth of the outer teeth 11b is an odd number, and the number of teeth of the outer teeth 11a and the outer teeth 11b are the same. Gear part 6a and rotor 5a.

The gear portion 6b and the rotor 5b are already firmly fixed together before the motor is assembled, with their respective central axes aligned. The zero-tooth differential gear mechanism 13a, 13b consists of internal teeth 9a, 9b formed on the gear portions 6a, 5b, and external teeth 8 formed with an output shaft IK shadow so as to mesh with the internal teeth 9a, 9b. In the example, the internal teeth 9a.

9b and the external teeth 8 have an even number of teeth.

FIG. 2 is a block diagram showing a method for controlling excitation of a variable air gap motor according to the present invention. The controller 60 can arbitrarily set the excitation phase difference. For example, the phase difference when the rotors 5a and 5b are actually installed (in this embodiment, the phase difference is 180
It is assumed that a new angle ``θ'' to be shifted from ``°'' is entered. Based on θ input to the controller 60, the phase difference generating means 61 shifts one of the excitation windings 3a and 3b provided along the inner peripheral surfaces of the two stators 2a and 2b by 180 degrees from the other. Generate a signal that gives a phase difference of 〇. Upon receiving this signal, the excitation switching means 62a on the stator 2a side and the excitation switching means 62 on the stator 2b side
b selects the winding to be excited at each moment from among 12 windings in this embodiment in order to realize the desired phase difference. Then, the drivers 63a and 63b sequentially change the current value applied to each winding.

In this embodiment with the above configuration, the controller 6
When "θ" is input to 0, the stator is excited as shown in FIG. Figure 3(a) shows Al-A in Figure 1.
The figure shows a cross section, and the rotor 5a is the stator 2a.
It is excited so that it is in contact with the point ■. On the other hand, as shown in Fig. 3 (b), which shows the BT-B' cross section in Fig. 1, the rotor 5b is in contact with the stator 2b at point 180 clockwise
It is excited with a phase difference of 100°. Figure 4 is this 2
This figure shows the excitation pattern of the two stators 2a and 2b, and excitation is always performed with a phase difference of 1800+θ.

By using such a method, the rolling mechanism 12a,
Internal teeth 10 and external teeth 11a in 12b.

11b, and the zero-tooth differential gear mechanism 13a.

Since pressure is applied to the meshing portions of the internal teeth 9a, 9b and the external teeth 8 in the tangential direction with respect to the central axis of the output shaft 1, the backlash is extremely reduced. Furthermore, since backlash generally has a particularly bad effect when the motor is stopped or started, the driver 63a generates the angle θ related to determining the phase difference when the motor is stopped or started.

The excitation control of 63b may also be used. Alternatively, excitation control may be performed such that the angle θ is changed in accordance with the acceleration of excitation switching of the winding. In this case, it is preferable to use a control method in which the positive/negative acceleration corresponds to the positive/negative angle θ.

Although this embodiment has been described with reference to the case where there are two stators and two rotors, the effects of the present invention are not limited to this embodiment, and similar effects can be achieved if there are a plurality of stators and rotors. Further, in this embodiment, a zero-tooth difference gear mechanism is used as part of the transmission means, but instead, an equal joint mechanism such as an Oldham joint mechanism may be used instead, and the position when the rotor is assembled is If excitation is performed with a phase difference different from the phase difference, backlash can be eliminated as much as possible.

〔Effect of the invention〕

As described above, according to the present invention, a variable gap type motor with less backlash is realized.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a variable gap type motor showing an embodiment of the present invention, FIG. 2 is a block diagram showing an excitation control method of the present invention, and FIG. 3 is a cross-sectional view of AI AI and 331- 33
The first sectional view and FIG. 4 are diagrams showing the excitation pattern of the stator. 1... Output shaft, 2a, 2b... Stator, 5a. 5b...Rotor, 12a, 12b...Rolling mechanism (transmission means), 13a, 13b...Zero tooth number differential gear mechanism (transmission means), 60, 61, 628, 62k), 63a. 63b...Excitation control means. (a) 3rd θ” fFiD” 3ω. ih 澾i <a) 4th (b) Figure I 尤Σ 1st I (b) Figure

Claims (1)

[Scope of Claims] A plurality of stators that generate a rotating magnetic field; and a plurality of rotors that have different center axes from the stators and that rotate around the center axis of the stator due to electromagnetic force caused by the rotating magnetic field and simultaneously rotate on their own axis. , an output shaft having the same central axis as the stator, a transmission means for transmitting the motion of the rotor to the output shaft, and an excitation control means for exciting the stator with a phase difference different from a phase difference when the rotor is assembled. A variable gap type motor characterized by comprising: