JPH01274657A - Pulse motor - Google Patents

Abstract

PURPOSE:To make a torque and a driving current proportional to each other, by superposing positive and negative bias currents on the driving current for two coils generating reverse torques of the same magnitude. CONSTITUTION:Salient poles 21-24...41-44 for three phases are formed in a stator 1. Salient poles 21, 22 are wound by coils 61, 62 (other salient poles are also wound by coils) to form two sets of A-C poles and A'-C' poles. The phases of teeth of facing salient poles are the same, while those of teeth of salient pole in positions differing 90 deg. from each other deviate by P/2 (P is the pitch of teeth 5). When an equal driving current is caused to flow from a current supply means 7 to the coils of A and A' poles, reverse torques of the same magnitude are generated to cancel each other. When positive and negative bias currents IAB and I'AB are superposed and caused to flow from said current supply means 7 to the A and A' poles, the torque T is composed and linearly proportional to the current including the zero point. The same may be said of other phases. Thus, a motor easily controlling torques can be manufactured at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improving the current-torque characteristics of a variable reluctance type (hereinafter referred to as VR type) pulse motor.

[Prior Art] An example of current-hold torque characteristics of a conventional VR type pulse motor is shown in FIG.

As shown in the figure, the hold torque T is proportional to the square of the current (hereinafter referred to as drive current) that flows through the motor coil to generate torque, but in a large current region, magnetic saturation occurs and the hold torque T The torque becomes saturated and the characteristic curve deviates from the quadratic curve.

[Problems to be Solved by the Invention] In a motor with such a characteristic curve, the relationship between the hold torque and the drive current I is non-linear, and the slope of the curve is close to 0 when the drive current I is near zero. The problem was that it was difficult to control.

Permanent magnet type pulse motors (PM type pulse motors) and hybrid type pulse motors have the characteristic that the hold torque is proportional to the drive current, but because they use permanent magnets, the material cost of the motor is high, and assembly is difficult. The problem is that it is troublesome.

The present invention was made in order to solve these problems at the same time, and an object of the present invention is to use a VR type pulse motor to realize a pulse motor whose hold torque is proportional to the drive current and which is easy to control. .

[Means for Solving the Problems] The present invention provides a pulse motor of the barrier pull reluctance type in which the generated torque is proportional to the square of the driving current of the coil. When an equal drive current is applied to the coils wound around each of the salient poles, the rotor generates torques of equal magnitude and in opposite directions, and a positive bias current flows through the coil wound around one of these salient poles. Apply a negative bias current to each coil wound around the other salient pole, drive each coil with the sum of the bias current and drive current, and make the sum of the torques generated by these salient poles proportional to the drive current. A pulse motor characterized by comprising: current supply means.

[Example] The present invention will be explained below using the drawings.

FIG. 1 is a diagram showing the main part of an embodiment of a pulse motor according to the present invention. This figure shows the configuration of the stator core of an outer rotor type motor with 12 salient poles and three-phase excitation.

In this motor, 1 is a stator, and salient poles 2° to 24.
3. ~3a, 4t~44 are formed. Each salient pole is wound with a coil, and teeth 5 at a constant pitch are formed at the tip. In FIG. 0, coils 61 and 62 wound around the salient poles 21 and 22 are shown, and the others are omitted. These coils each constitute one phase with the coils wound around the salient poles 21 to 2a, 3+ to 3a, and 41 to 44.

For salient poles wound with coils of the same phase, the teeth of the salient poles located opposite each other have the same phase, and the teeth of the salient poles located 90' apart have a phase shift of p/2 (p is the phase of tooth 5). Pitch) 0 For example, the teeth of salient poles 21 and 22 are in the same phase, and the teeth of salient poles 21 and 22 are in the same phase.
The phases of the two salient poles and 24 are shifted by p/2 with respect to those of 21 and 22.

The same applies to salient poles around which coils of other phases are wound.

Also, salient pole 2. The phases of the teeth ~2a, 3t~3m, and 41 to 44 are shifted by P/3.

From this, salient poles 21, 22.23 and 24.3
t, 32.33, 34.41, 42.43 and 44 respectively as A pole, A' pole, B pole, B' pole, Cf#! , C' pole.

Reference numeral 7 denotes a current supply means for supplying current to the coil wound around the salient pole.

Salient poles that are in the same phase and located opposite each other, for example, salient poles 21 and 2
The two coils are wound in the same direction and connected in series.

FIG. 2 is a diagram showing the tooth tip shapes of the stator core and rotor core and their relative positional relationship, and in this diagram, the stator and rotor are shown expanded.

In FIG. 2, reference numeral 8 denotes a rotor having teeth 9 facing the teeth 5 and having the same pitch as the teeth.

When such a motor is in the relative tooth tip position shown in FIG. 2, the coil 61 of the salient pole 21 and the coil 64 of the salient pole 24
When driving currents IA and IA' are applied to each salient pole 2.
The generated torques of and 24 are as shown in gl and g4 in Fig. 3. The graph in FIG. 3 shows the generated torque on the vertical axis and the drive current on the horizontal axis.

When the drive current is IA = IA', the torques T1 and T4 generated by the salient poles 21 and 24 are T1'' (IA)2
+Ta''(IA')', and since the proportionality constants are equal, T='l''4. Since these torques are equal in magnitude and act in opposite directions, the salient pole 2
The hold torque 'r0 based on 1 and 24 becomes T o =T 1T a = O.

Therefore, in the motor according to the present invention, the drive current IA and T
Positive and negative bias currents IA8 and JA whose magnitude is equal to A'
B' and the sum of these currents is flowing through the coil. Therefore, the current flowing through the coil is IA = IA + IAa IA' = IAI ' - IA8 '. Here, IAI and TAI' are drive currents.

As a result, torques T and T4 become 'I'l'C(IA1+IAEl)''I',0C(IAt'IAB')',
Since the proportionality constants are equal, the hold torque T0 due to the salient poles 21 and 24 is T, =T, -'l''4 0C(TA1+TAB)'(141'IAB')'.The drive currents IAI and IAI' are If equal, 1'
It becomes O″4・IA1・IAB′.

A graph of these relationships is shown in Figure 4. In this figure, the graphs f and T4 are the generated torques T and T4 of the salient poles 21 and 24, and the graph fo is the torque ai2. and 2. It is a graph of hold torque TO by l.

As shown in the graph, the hold torque 'r0 is T1 and T4 when the drive current IA I =TA I' =O
are equal in magnitude and act in opposite directions, so they become 0. Also, the hold torque is 1゛. is the torque ′r, and T
4 becomes a proportional straight line in the current region where it does not reach saturation (does not deviate from the quadratic curve).

The above relationship was about the A and A' poles, but
The same holds true for the other B[4 and B' poles, and the C and C' poles.

When the drive current is set to a predetermined condition in this way, the generated torque, that is, the hold torque, is proportional to the drive current.

In the embodiment, a motor with three-phase excitation has been described, but the motor is not limited to this, but may be one with two-phase excitation or other multi-phase excitation.

In addition, in the embodiment, a case has been described in which one phase is provided with a salient pole with a phase of 2il teeth, but even if the configuration is not limited to this and one type of salient pole is provided in one phase, it is possible to A configuration may be adopted in which many types of salient poles are provided. However, the number of types of salient poles per phase must be the same for all phases.

[Effects] According to the present invention, since the holding torque is made proportional to the drive current by passing a bias current through the coil of the salient pole, the motor can be easily controlled.

Further, while taking advantage of the advantages of the VR type pulse motor that material costs are low and assembly is easy, proportional characteristics equivalent to those of the PM type pulse motor can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of essential parts of an embodiment of a pulse motor according to the present invention, FIG. 2 is an exploded view of the motor in FIG. 1, and FIGS. 3 and 4 are explanatory diagrams of the operation of the motor in FIG. 1. , FIG. 5 is a torque-current characteristic diagram of a conventional pulse motor. 1... Stator, 21~2a, 31~34.4t~
44... salient pole, 5, 9... tooth, 6+, 62.6a
... Coil, 7... Current supply means, 8... Rotor. Figure 1 Figure 3 To Figure 4

Claims (1)

[Claims] In a variable reluctance type pulse motor in which the generated torque is proportional to the square of the driving current of the coil, the pulse motor is provided in pairs on the stator and is wound on each coil. When an equal drive current is passed through the rotor, there are salient poles that generate equal and opposite torques on the rotor, and a positive bias current is applied to the coil wound around one of these salient poles, and the positive bias current is applied to the coil wound around the other salient pole. a current supply means for applying a negative bias current to each of the coils, driving each coil with the sum of the bias current and the drive current, and making the sum of the torque generated by these salient poles proportional to the drive current. Features a pulse motor.