JPS60245458A - Movable iron piece type motor - Google Patents

Abstract

PURPOSE:To increase generated torque without increasing the inertia of a rotor by forming salient-poles aligned alternately at N- and S-poles from stator poles, forming a rotor to have movable iron piece having salient-poles, and further disposing coils in the gap of the stator salient poles. CONSTITUTION:A ring-shaped permanent magnet 4 axially magnetized at N- and S-poles are interposed at both axial sides between stator poles 5 and 6, and salient poles 51-58 and 61-68 provided on the inner periphery are alternately arranged in the same plane. A rotor 7 made of a movable iron piece having salient poles 71-77 of the number different by 1-3 from the number of the salient points opposed to the poles 51-68 of the stator side are supported. Further, two or more coils 8, 9 are mounted at an equal interval in the gaps of the poles 51-68 of the stator and energized. Thus, the generated torque can be increased without increasing the inertia of the rotor 7 to reduce the no load rotating speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a movable iron piece motor having a novel configuration.

[Prior art]

Conventionally, a DC motor as shown in FIG. 1 has been known as a motor that performs an operation similar to the movable iron piece motor of the present invention. In the figure, 1 is a permanent magnet, 2 is a rotor, and 3 is a permanent magnet.
is a coil wound around a slot provided on the outer periphery of the rotor 2. In such a DC motor, a current corresponding to the magnetic pole of the magnet 1 is supplied to the coil 3 by the action of the brushes and the commutator, and torque is always generated in a constant direction.

Now, focusing on the coil part a in the figure, and including the change 0Φ in the number of interlinked magnetic fluxes in the coil part a when the rotor 2 rotates by a small angle θθ, we get θΦ= 2B11m - p'l'p -θθ (1) Here, Bgm: Magnetic flux density of the gap Qp: Length in the axial direction of the rotor 2 rp0 Radius of the rotor 2. Since the generated torque is proportional to θΦ/θθ, generally a method of increasing Qp and rp is used to increase the generated torque. However, since the inertia 1m of the rotor 2 is In+c rLp -rp' (2), especially if rp is made too sharp, Tm will increase and the responsiveness of the system including the load will deteriorate. There is also a method of significantly increasing QP while keeping trP small, but it is difficult to manufacture and
As the length per turn becomes longer, the required current cannot flow due to the increase in DC resistance. Furthermore, in the case of the shape shown in the figure, the magnetic poles of magnet 1 are two poles, and if this is changed to four poles, the generated torque can be doubled.This also increases the number of coils and commutators. However, it becomes difficult to manufacture.

[Purpose of the invention]

The present invention eliminates the drawbacks of the conventional devices as described above, and provides a simple movable iron piece type motor that can increase the generated torque without increasing the inertia of the rotor and lower the no-load rotation speed. The purpose is to realize this through configuration.

[Summary of the invention]

The movable iron piece type motor of the present invention has stator magnetic poles composed of convex poles in which N poles and S poles are alternately arranged, and
The rotor is also a movable iron piece with a convex pole structure facing these convex poles, and two or more coils wound on a flat sheet passing through the axis of the rotor are equally spaced between the convex poles in the stator magnetic poles. They are arranged at intervals.

〔Example〕

FIG. 2 is a configuration diagram showing an embodiment of the movable iron piece type motor of the present invention. FIG. 2(a) is a longitudinal sectional view of the rotor in the axial direction, and FIG. 2(b) is a horizontal sectional view. In the figure,
4 is a ring-shaped permanent magnet magnetized in the axial direction, 5 and 6 sandwich the magnet 4 from both sides, and the convex poles 51 to 58
, 61 to 68 are combined so that they are arranged alternately on the same plane, and 7 is opposed to the convex poles 51 to 58 and 61 to 68 of the stator magnetic poles 5 and 6, and for example, The rotors 8 and 9, each having seven convex poles 71 to 77, are wound on a plane passing through the axis of the rotor 7, and are mechanically deviated by 90 degrees. The coil is placed so as to pass between the convex poles. In the figure, the coil 8 is arranged to pass between the convex poles 51 and 68 and between 55 and 64,
The coil 9 is arranged to pass between the convex poles 53 and 62 and between 57 and 66. Further, the rotor 7 is a movable iron piece-shaped rotor made of a ferromagnetic material.

The operation of the movable iron piece motor of the present invention configured as described above is as follows.

In the state shown in the figure, if current is supplied only to the coil 8, the rotor 7 is excited by the magnetomotive force, and the convex poles 71 to 74 become S poles and the convex poles 75 to 77 become N poles. Therefore, the magnetic flux density at each convex pole portion of the stator magnetic poles 5, 6 and the rotor 7 becomes unbalanced, and a torque is generated in the rotor 7 according to the change in the magnetic flux density. Note that, here, the magnetic poles generated in the rotor 7 due to the magnetomotive force of the coil 8 are represented by lowercase letters n and s.

At this time, when looking at the change 0Φ in the number of interlinkage magnetic fluxes of the coil 8 with respect to the minute rotation angle 8θ of the rotor 7 in the same way as the above equation (1), 0Φ=3・28gm −ip −Yp−Bθ (3 ), making it almost three times as large. Therefore, if the conditions such as the magnetomotive force of the magnet 4 and the shape of the rotor 7 are made similar to those of the DC motor shown in FIG.

In addition, in the state shown in the figure, when the rotor 7 is gradually rotated, the magnitude of the torque at each position of the rotor 7 is the third
Changes as shown in the figure, 177 rotations (2v/7 rad)
It will change for one cycle. Similarly, when a current is supplied to the coil 9, a torque that is 90 degrees out of color phase can be obtained.

Therefore, by detecting the rotation angle of the rotor 7 using an encoder or the like and selectively supplying current to the coils 8.9, it is possible to always generate torque in a fixed direction.

Note that the waveforms in FIG. 3 are shown assuming that the size of the gap between the convex poles is very small compared to the radius of the rotor 7, but in reality, the gap may be increased to some extent. Therefore, the corners of the waveform are removed, resulting in a smooth waveform as shown in FIG.

FIG. 5 shows the generated torque when the current supplied to the coil 8.9 and its polarity are switched every 174 pitches, and FIG. 6 shows an example of the drive circuit. As shown in the figure, by controlling the connection state of switches s1 and s2 according to the rotation angle of the rotor 7, a current proportional to the control voltage 1 can be supplied to the coils 8 and 9 with arbitrary polarity and timing. can do. Here, the torque ripple in Fig. 5 is 118%,
There is no practical problem, but if you want to further reduce the torque ripple, double the number of coils, arrange them with a 45 degree phase difference, and switch the current every 1/8 pitch. For example, the torque ripple can be set to ±5%.

Now, in general, in a motor, if the magnetomotive force when a current I flows through a coil wound N times is N・■, then the generated torque T is expressed as T=N・I(θO/a&) (4) It will be done. Also, N-1 is N-summer = Ps-3c Qc ・ pc] (5)
Ps, startup input power Sc: total cross-sectional area of copper in the coil Qc: length of one turn of the coil ρC1 Also expressed as specific resistance of copper.

Therefore, in order to increase the generated torque T in a general motor, it is necessary to increase the number of turns (N or Sc) of the coil or to increase the starting power Ps.

However, in a motor in which the coil 3 is wound in the slot of the rotor 2 like the motor shown in FIG.
The number of turns of the coil 3 cannot be increased unconditionally. On the other hand, in the motor shown in Fig. 2, the coil 8.9 is wound on the side of the stator magnetic pole 5.6, so this Sc can be relatively freely increased, and the starting power Ps can be reduced to a small value. The required torque can be obtained even if the value is set to a certain value.

Furthermore, when considering the relationship with the no-load rotational speed ω0, it is common that the voltage Vs applied at startup is continued to be applied even at the maximum rotation. At this time, the applied voltage Vs and the counter electromotive force C have the same value, and no current flows through the coil. Therefore, if losses such as friction are ignored, C=(0Φ/'i3θ)・N・ωo (6) Ps=Vi
The relationship ・I (7) holds, and from the above equation, Ps=T・ωo(8), and the starting power Ps is uniquely determined from the required torque T and the no-load rotational speed ω0.

On the other hand, from Equations (4), (5) and (8) in 1liJ, ω0 = PS・(C-ρC/SC /(θΦ/aθ) (9), so no load is applied while the torque T remains large. When trying to lower the rotational speed ω0, it is necessary to increase Sc, and as mentioned above, it can be seen that the motor shape shown in Fig. 2 is suitable.Also, similarly, it is necessary to increase 0Φ10θ. is also a means, and is very advantageous in this respect as well.

Furthermore, regarding the structural features, in the motor shown in FIG. 2, the coils 8 and 9 are first wound and placed inside the ring-shaped magnet 4, and the stator magnetic poles 5 and 9 are placed between them.
The assembly of the stator side can be completed by simply combining 6 parts, making it easy to assemble and requiring only 2 coils even though it has a multi-polar structure, making it possible to realize an inexpensive motor. .

In addition, in the above explanation, the case where the number of convex poles of the rotor 7 is one fewer than the number of convex poles of the stator magnetic poles 5.6 was illustrated, but the number of convex poles of the rotor 7 is The number is not limited to this, but the same operation can be performed as long as it is in the range of ±1 to 3 compared to the number of convex poles in the stator magnetic poles 5 and 6. In this case, the timing of switching the current supplied to the coils 8.9 changes depending on the number of convex poles.

〔Effect of the invention〕

As explained above, in the movable iron piece motor of the present invention,
The stator magnetic poles are constituted by convex poles in which N poles and S poles are arranged alternately, and the rotor is also a movable iron piece with a convex pole structure that faces these convex poles, and the gap between the convex poles in the stator magnetic poles is Since two or more coils wound on a plane passing through the axis of the rotor are arranged at equal intervals, the generated torque can be increased without increasing the inertia of the rotor. A movable iron piece motor capable of lowering the load rotation speed can be realized with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional DC motor, and FIGS. 2 to 6 are block diagrams showing one embodiment of a movable iron piece type motor of the present invention and explanatory diagrams of its operation. 1.4...Permanent magnet, 2,7...Rotor, 3°8.
9... Coil, 5.6... Stator magnetic pole. Agent: Patent Attorney Shinsuke Ozawa (Figure 1)

Claims (1)

[Claims] A ring-shaped permanent magnet magnetized in the axial direction, two stator magnetic poles that sandwich this permanent magnet from both sides and are combined so that their convex poles are arranged alternately on the same plane, and a ferromagnetic material. a rotor having a number of convex poles that are opposite to the convex poles of the stator magnetic poles and whose number differs by 1 to 3 from the number of convex poles, each wound on a plane passing through the axis of the rotor; A movable iron piece type motor comprising two or more coils arranged with a certain phase difference so as to pass between the convex poles of the stator magnetic poles.