JPS5836158A - Semiconductor motor with air core coil as position detector - Google Patents

Abstract

PURPOSE:To facilitate the positioning of drive coil and position detecting air core coil by forming a position detecting band of a conductive nonmagnetic material which has teeth of number half of the number of poles on the magnetizing surface of a field magnet and integrally winding both the coils. CONSTITUTION:A bearing 2 is press-fitted into an upper housing 4, and a rotational shaft 1 is rotatably supported at the bearing 2. A magnet holder 9 and an annular field magnet 7 are integrally secured to the shaft 1. The first magnetic yoke is secured to the opposite side to the magnetizing surface of the magnet 7, and a position detecting band 8 made of conductive nonmagnetic material which has teeth of the number of half of the number of poles is secured to the magnetizing surface. A lower housing 5 is engaged with the upper housing 4, supports at the center the shaft 1, and a drive coil 11a and a position detecting air core coil 11b are integrally wound. In this manner, the positioning of both the coils can be very accurately performed, and the size can be effectively reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor motor using an air-core coil connected to an oscillator as a means for detecting.

In general, in a field magnet rotating type semiconductor motor, the means for detecting the magnetic pole position of the field magnet is an optical method, a method using a magnetically sensitive element, or a method based on detecting changes in inductance of a cored oscillator coil. etc. are used, but
In both cases, it is difficult to position the elements, and a relatively large space is required for arranging the elements, making it difficult to miniaturize the motor.

The present invention eliminates the above-mentioned drawbacks and provides a semiconductor motor that is easy to position and suitable for miniaturization.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

Note that the same symbols in the figures indicate the same members or the same functions.

FIG. 1 is a sectional view of a semiconductor motor according to the present invention. A bearing holder 3 is fixed to the pressed upper housing, and a bearing is press-fitted into the bearing holder 3. Further, a rotating shaft l is rotatably supported on the bearing, and a magnet holding member 9 is attached to the rotating shaft l within the housing.
A flat, annular field magnet 7 is fixed so as to rotate together.

A first magnetic yoke 6 is fixed to the field magnet on the side opposite to the magnetized surface, forming a magnetic path on the upper surface. Further, a position detection band g made of a conductive non-magnetic material and having half the number of teeth as the number of magnetized poles is fixed to the magnetized surface. The position detection band S is made of aluminum here (details will be described in FIG. 3).

The lower casing S is fitted into the upper casing D, and has a thrust bearing /θ disposed in the center thereof to support the rotating shaft /. Further, the lower housing S forms a first magnetic material yoke through a gap with the field magnet 7, and a coil group /I, which is an integrated drive coil and an air-core coil, is fixed in the gap. .

As shown in detail in FIG. 2 (α), the coil group /l has a fan shape, and includes a drive coil //α and an air core coil //
b are wound by the same winding frame.

The state shown in FIG. 1 is the Aj cross section in FIG. 2 (b).

The drive coil //-6 and the air-core coil l/-A start winding from the terminal X located at the innermost circumference and end at the terminal Y for the intermediate tap.
After deriving , Y・, it reaches the terminal l from the outermost periphery. Note that the intermediate tap terminals Y and Y' may be made into a single wire by twisting them together or the like. The drive coil //-A is connected to the drive current control transistor, and the air-core coil //-A is connected to the oscillator. The oscillator will be explained using FIG. q.

The circuit shown in FIG. 2(a) is a Kolbitz oscillator, which is a well-known circuit in which a tank circuit is formed by capacitors C/, C-co and an air-core coil//-b, and is driven by a transistor Q. Here, in the air core coil //1b,
FIG. 2(h) shows the collector waveform when a conductive member approaches and separates from the outside during oscillation. The collector waveform is a voltage waveform between the terminal P and the ground, and is a waveform in which the conductive member is brought into contact and separated as time passes. Therefore, the horizontal axis represents time t, and the vertical axis represents voltage V.

In FIG. 1(A), a position where the amplitude is 1 unit larger is a state where the conductive member is away from the air-core coil, and a position where the amplitude is small is a state where the conductive member is close. This is because the inductance of the air-core coil A changes due to eddy current loss in the conductive member. If this phenomenon is utilized to cause a conductive member to approach and separate from the air-core coil in correspondence with the south pole of the field magnet, the magnetic pole position can be detected without contact.

The above conductive member is a position detection band, the details of which are shown in Figure 3. .

Figure 3 (α) shows the field magnet used in this example. As shown in the figure, the N and S poles are alternately magnetized at equal opening angles. In this case, the position detecting body S is as shown in FIG. 3(A).
It has half the number of magnetic poles (here, ?'i number) of toothed parts g-α with diagonal lines as shown in the figure, and the area of the toothed parts almost covers the air-core coil //-A. . Further, the opening angle of one of the teeth is the same as the opening angle of one magnetic pole of the field magnet (here, 90 degrees).

By the way, as is clear from FIG. 1, since the drive coil is disposed below the position detection band, the position detection band is prevented from closing the magnetic path of the field magnet 7 by the position detection band. Band t must be made of a conductive but non-magnetic material.

Therefore, in this embodiment, an aluminum plate is used.

Next, a developed winding diagram of an embodiment according to the present invention will be explained with reference to FIG.

The teeth of the position detection band g are provided centered at the boundary where the magnetic pole of the field magnet 7 changes from 8 to N along the arrow direction as shown in the figure.

Also, the drive coils are //-a, iλ-α, /, ? -tL
There are three transistors, each arranged 120 degrees apart, one end of each connected to the power supply positive terminal, and the other end connected to the drive transistors Q-/, Q-1.

Further, the emitters of each of the transistors Q-/, Q-, and 2IQ-3 are connected to the power supply negative terminal unit 1, and the bases are connected to the output terminal of the drive current control circuit qθ. An output signal from a position detection circuit 30 including an oscillation circuit is input to the input terminal of the current control circuit qθ.

In the configuration described above, when the relative positional relationship between each coil group and the field magnet is as shown in Figure 3, the power supply to the drive coils is as follows. Of these, //-6 is not covered at all by the teeth t-α of the position detection band, and most of the area of the other air-core coils /2-4 and /3-4- is covered. Therefore, only the output of the oscillator by the air-core coil //-/ has a large amplitude, and a signal is output from the corresponding terminal of the position detection circuit 3θ, and the drive current control circuit ψ makes the transistor Q-/ conductive and drives it. A current flows through the coil //-α as indicated by the arrow/mark on the diagram. The effective conductor portion that should contribute to the torque generation of the drive coil //-α is now exactly N.

The field magnet, which is located at the center of the S pole and is a rotor, rotates in the direction of the arrow by the above-described energization. Next,
The air-core coils i and y-b are no longer affected by the teeth of the position detection band -α, which rotate together with the field magnet, and current flows through the drive coil /3-α, causing the field magnet to rotate. The rotation in the direction of arrow 7 is taken over, and then the drive coil/
--The rotation is maintained by applying current to a.

As is clear from the above description, in the semiconductor motor according to the present invention, since the drive coil and the air-core coil for position detection can be integrally wound, positioning becomes extremely accurate.
Furthermore, since it fits within the hollow part of the drive coil, it is extremely effective in downsizing the electric motor.

Next, a configuration for more reliably obtaining a large change in the oscillation amplitude of the air-core coil will be described.

As can be seen from FIG. 1, the air-core coil //-A can be configured to be in contact with the lower housing 3, but in this case, if the lower housing 5 is conductive, the oscillation amplitude will be reduced. Initially, the force i is limited by the approach of the conductive part side, and therefore the influence of the approach of the tooth section α of the position detection band g becomes minute. Therefore, it is sufficient to create a structure in which a gap is provided between the lower housing S and the lower housing S in advance, as shown in Fig. 2 (
h) shows its cross-sectional view. The symbol //-C is a drive coil, and the air-core coil tt-cL is connected to the lower casing S by a non-conductive winding frame 15 (plastic in this case) through the air gap, and the hollow part of the drive coil //-C. Fixed inside. With this configuration, the winding frame/S
It is possible to use the coil as it is as a fixing member to the lower housing, and the lower housing 5 can be fixed with a screw /A into the recess 15-α provided in the center of the winding frame /S as shown in the figure.
Can be installed on. Although it is possible to make the amplitude change larger with this method, it is also possible to
By molding the yoke using a powdered iron core, it is possible to obtain a large amplitude change without impairing the characteristics of the yoke.

FIG. 6 shows an embodiment in which the electric motor according to the present invention is used as a fan motor.

A bearing S is fitted into the center of the lower cylindrical body made of a magnetic material, and the rotating shaft 51 is rotatably supported by the bearing S. A center hole of a fan 56 machined from a magnetic material is fitted into the rotating shaft 52, and the upper part is fixed by a screw 5q provided on the head of the rotating shaft 51, and the lower part is fixed. Q It is fixed by IJung SO etc.

A field magnet 57 is fixed to the lower part of the fan 56, and a position detection band sg made of a non-magnetic material is fixed to the magnetized surface of the field magnet 57. The air-core coil 5t and the drive coil S3 are fixed to the lower casing directly below the field magnet 57 via a gap.

With the above configuration, it can be used as both a fan and a yoke, and is easy to assemble and can be formed into an extremely flat shape, making it easy to attach to various devices.

As described above, according to the electric motor according to the present invention, the objects mentioned at the beginning are achieved and the effects are significant.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an embodiment according to the present invention, and Fig. 2 (α) (
b) is a detailed view of the coil group, Figure 3 (α) is a detailed view of the field magnet, Figure 3 (h) is a detailed view of the position detection band, and Figure 4 (α) is a detailed view of the field magnet.
) is a circuit diagram of the oscillation circuit, diagram (b) is a waveform diagram of the oscillation circuit, FIG. 5 is a developed winding diagram of an embodiment according to the present invention, and FIG. 6 is a sectional view of another embodiment according to the present invention. are shown respectively. /, 51...rotation axis, ko, 10, 32...
Bearing, 3...Bearing holder, q...Upper cylinder,
S. SS...lower housing, 6...yoke, ri, 57...field magnet, g, 5g...position detection band, g-α...teeth, evening...magnet holding material ,
l/... coil group, //-a//-ct code α /3-a53... drive coil, //-A,
//-d, /2-A. /, 3-b, '; Hiroshi...air-core coil, 15...
Winding frame, /Otsu...Screw, Ko0,2/...Power terminal,
30... Position detection circuit, qo... Drive current control circuit, 56... Fan, S9... Nut,
c-t, c-sce capacitor, Q, Q'i
+Q-co. Q-, 7...transistor, X, Y, Y', l.
...Coil terminal. Patent applicant 弗 l Figure 弗 2 Figure (α) 3rd (a→ 4th (a) Figure (7) Figure (-/l)

Claims (1)

[Scope of Claims] (1) A multipolar field magnet that rotates together with the rotating shaft and has a first magnetic material yoke fixed to the side opposite to the magnetized surface, and fixed to the magnetized surface of the field magnet. a position detection band made of a conductive non-magnetic material having half the number of teeth as the number of magnetized poles; and a first magnetic yoke provided opposite to the magnetized surface of the field magnet with an air gap interposed therebetween. , a plurality of drive coils fixed to the first magnetic material yoke within the air gap, an air-core coil wound within a hollow portion of the drive coil, and an oscillator including the air-core coil; A semiconductor motor using an air-core coil as a position detector, characterized in that the motor includes a control circuit that controls a drive current of the drive coil. (2) A semiconductor device using a patented coil as a position detector, characterized in that the drive coil and the air-core coil are wound using the same winding frame, and an intermediate tap is derived from the boundary between the drive coil and the air-core coil. Electric motor. (8) Claim No. (8) characterized in that an air gap is provided between the air-core coil and the second magnetic material yoke.
A semiconductor motor using the air-core coil described in items 1) and 2) as a position detector. (4) Claims (1), (2), characterized in that a fan is integrally provided to the/th magnetic material yoke.
A semiconductor electric motor using the air-core coil described in paragraphs ) and (8) as a position detector. (5) The air-core coil according to claim 1, wherein the center of the teeth of the position detection band is located at the boundary between adjacent magnetic poles of the field magnet. Semiconductor motor used as a detector.