JPS60170456A - Brushless motor having frequency generator - Google Patents

Abstract

PURPOSE:To reduce the size and the cost by forming drive and frequency detecting poles on the surface of a magnet, and forming a conductive pattern for forming a frequency generator oppositely to the pole for detecting the frequency. CONSTITUTION:A magnet 5 is disposed oppositely to a stator armature 3. This magnet 5 has a drive pole 5a having N- and S-poles and a frequency detecting pole 5b formed at the periphery. A pectinated conductive pattern 8 for forming a frequency generator is formed oppositely on the pole 5b. A magnetic sensor is disposed on a printed board 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brushless motor with a frequency generator.

Brushless motors with frequency generators have been known in the past, but most conventional brushless motors require a separate frequency generator, and even if they have a built-in frequency generator, they still do not have frequency generators. The disadvantage is that it takes a long time to assemble a brushless motor with a machine, and it is also large, making it unsuitable for mass production and making it large and expensive.

For this reason, in the past, N and S
A stator armature is arranged on the fixed side facing the drive magnetic pole, and a stator armature is arranged on the fixed side opposite to the drive magnetic pole, and a frequency detection magnetic pole is further magnetized on the drive magnetic pole surface. By arranging a comb-shaped conductive pattern for forming a frequency generator on the opposing stator armature surfaces, the drawbacks of brushless motors having a frequency generator have been solved.

However, in a brushless motor having such a useful frequency generator, the field magnet must be magnetized twice: magnetization to form a drive magnetic pole and magnetization to form a frequency detection magnetic pole. Must be. Moreover,
Unless the drive magnetic pole and the frequency detection magnetic pole are properly aligned, a frequency power generation signal for accurate rotational speed detection cannot be obtained. As described above, because of the two-time magnetization and troublesome alignment work, it is difficult to mass-produce a brushless motor having a high-performance frequency generator at a low cost.

However, since it is necessary to perform magnetization twice as described above, there is a drawback that a magnetizer that cannot be used to form a magnetic pole for frequency detection must be used, which is expensive.

The present invention has been made in view of the above-mentioned drawbacks of the conventional art, and it is possible to form a compact brushless motor with a built-in frequency generator, and it eliminates the need for a magnetizer for forming magnetic poles for frequency detection. Eliminates the need for magnetization for magnetic pole formation,
By simply performing magnetization to form the drive magnetic pole, and at the same time using a field magnet in which the frequency detection magnetic pole is integrally formed in the correct position and the frequency detection magnetic pole is formed within the drive magnetic pole, high performance can be achieved. This was done with the aim of making it possible to mass-produce brushless motors with frequency generators at low cost.

In the brushless motor having the frequency generator of the present invention, a magnet such as a plastic magnet is formed so as to have ring-shaped irregularities with fine gaps on the surface facing the stator armature, and N is formed on the magnet surface having the irregularities. , S magnetic poles are alternately formed into a 2p (p is a positive integer of 1 or more) driving magnetic pole to form a frequency detection magnetic pole on the concave and convex portion of the magnet, and the frequency detection magnetic pole is Arranging conductive patterns for forming a comb-like frequency generator to face each other, and forming a frequency generator with the conductive patterns and the frequency detection magnetic poles, or a stator armature surface facing the frequency detection magnetic poles. This is achieved by disposing a magnetic sensor in the magnetic pole and forming a magnetic encoder with the frequency detecting magnetic pole and the magnetic sensor.

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

A first embodiment of the present invention will be described using FIGS. 1 and 2.

FIG. 1 is a longitudinal sectional view of a disc-type brushless motor having a frequency generator according to a first embodiment of the present invention, and FIG. 2 is an exploded perspective view of the main parts of FIG. 1.

Reference numeral 1 denotes a disc-type brushless motor having a frequency generator, a casing of the disc-type brushless motor 1 made of two magnetic materials, and 3 a stator armature fixed to the inner surface of the upper surface of the casing 2. The stator armature 3 is formed by arranging six fan frame-shaped armature coils 4 at equal intervals so as not to overlap each other. armature coil 4
are the conductor parts 4a and 4b that contribute to the generated torque in the radial direction.
The opening angle with the driving magnetic pole 5 of the field magnet 5, which will be described later, is
The opening angle width is approximately equal to the width of a, that is, as will be explained later, since one driving magnetic pole 5a of the field magnet 5 has eight poles, the opening angle width is approximately 45 degrees. It has become. The circumferential conductor portions 4c and 4d of the armature coil 4 are as follows:
It is a conductor portion that does not contribute to the generated torque. 180 degree symmetrical armature coils 4-1 and 4-4, 4-2 and 4-5
, 4-3 and 4-6 each form one phase, and this disk type brushless motor 1 constitutes a three-phase brushless motor. One position sensing element 6 is used for each two armature coils forming each phase. Therefore,
In a three-phase brushless motor, three position sensing elements 6 are arranged on a surface of a printed circuit board 7 (to be described later) that faces an in-frame cavity 4A of the armature coil 4. Position sensing element 6
Examples include Hall element, Hall IC, MR (magnetoresistive)
A magnetoelectric conversion element such as an element is used. Stator armature 3
An annular printed circuit board 7 is fixed to the lower surface of the magnet 7, and faces a field magnet 5, which will be described later.

A comb-shaped conductive pattern 8 for forming a frequency generator is formed on the outer periphery of the lower surface of the printed circuit board 7, and faces a frequency detection magnetic pole 5b, which will be described later, and is connected to the conductive pattern 8 and a frequency detection magnetic pole 5b, which will be described later. Together with the magnetic pole 5b, it forms a frequency generator for detecting the rotational speed of the rotor. 9 and 10 are bearings provided approximately at the center of the casing 2; 11;
is a rotating shaft rotatably supported by a bearing 9°10,
Reference numeral 5 denotes a field magnet that forms the rotor body integrally formed with the rotating shaft 11 and molded with a ferrite magnet or a plastic magnet, and the field magnet 5 faces the conductive pattern 8 of the printed circuit board 7 fixed to the stator armature 3. so that it has alternating concavities and convexities in a ring shape with a minute pitch.
8 driving magnetic poles 5 having N and S magnetic poles alternately on a disk-shaped magnet formed integrally with the rotating shaft 11
By magnetizing the magnet in the thickness direction using an appropriate magnetizer so as to form a magnet, a frequency detection magnetic pole 5b is formed integrally with the drive magnetic pole 5a on the uneven portion of the magnet. At the same time, they are magnetized and formed.

By doing so, the field magnet 5 having the drive magnetic pole 5a and the frequency detection magnetic pole 5b is provided integrally with the rotating shaft 11 to form a rotor.

In this way, when the magnet and the rotating shaft 11 are molded together, the magnet is formed with uneven parts at a fine pitch in advance, and the driving magnetic pole 5a is simply attached once to the magnet surface having the uneven parts. Just by forming the magnet, the frequency detection magnetic pole 5b is also formed in the correct position at the same time, so after performing the correct positioning as in the conventional case, the second magnetization, that is, the formation of the frequency detection magnetic pole, is performed. Since it is necessary to form magnetization, it is possible to mass-produce the disc-type brushless motor 1 having the frequency generator with good performance at low cost. Since there is no need for an expensive magnetizer to magnetize the frequency detection magnetic pole 5b, the brushless motor 1 can be provided at low cost in this respect as well. Furthermore, when molding to integrate the magnet and the rotating shaft 11, positioning is required in advance, so the rotor yaw or non-magnetic plate is fixed to the rotating shaft 11 as in the past. It is possible to solve the problem of fixing the field magnet 5 to the rotor yaw or the non-magnetic plate when adjusting the fixing strength and the balance, so it is possible to obtain the disk type brushless motor 1 with good rotational balance. can.

Concave portion 5c and convex portion 5d of the frequency detection magnetic pole 5b forming portion
are formed in advance at the time of the magnet molding so that 90 pieces are alternately arranged along the circumferential direction with fine pinches. After that, when the driving magnetic pole 5a is magnetized and formed as described above, the uneven portion 5 c + 5 of the magnet is formed.
As a result, 180 frequency detection magnetic poles 5b having N and S magnetic poles alternately arranged at fine pitches along the circumferential direction are formed in the d portion. That is, the N-pole driving magnetic pole 5a
In the fourth part 5c, a weak N' pole, that is, an S-pole magnetized part is formed, and in the convex part 5d, a strong N-pole magnetized part, that is, an N-pole magnetized part is formed, and it is still used for driving the S pole. In the magnetic pole 5b, the concave portion 5c has the same function as an S' pole, that is, an N-pole magnetized portion is formed, and the convex portion 5d has the same function as a strong S-pole magnetized portion, that is, a S-pole magnetized portion is formed. It depends.

The frequency detection magnetic pole 5b faces the conductive pattern 8 formed on the printed circuit board 7 with a small gap in between. The conductor portion 8a of the conductive pattern 8 that contributes to power generation in the radial direction is the uneven portion 5 of the frequency detection magnetic pole 5b.
c, the pitch is the same as that of 5d. Therefore, every other line segment (conductor portion) 8d group in the radial direction of the conductive pattern 8 is
For example, the recess 5 that acts as the N pole of the frequency detection magnetic pole 5b
c or the convex portion 5d, the group of line segments 8a therebetween face the concave portion 5a or the convex portion 5d which acts as an S pole. As a result, an electromotive force in the same direction is generated in each line segment 8a group according to the relative rotational speed of the frequency detection magnetic pole 5b, and a detection output of a frequency corresponding to the rotational speed of the rotor is generated from the output terminal (not shown) of the conductive pattern 8. can get.

The driving magnetic pole 5a of the field magnet 5 faces the stator armature 3 made up of four groups of six armature coils via a printed circuit board 7 made of a non-magnetic material. Therefore, the stator armature 3 and the driving magnetic poles 5a form a disk-type brushless motor. Therefore, the position detection element 6 detects the N pole and S pole of the drive magnetic pole 5a, and the predetermined armature coil 4-1. ..., 4-6, the rotor equipped with the field magnet 5 having the driving magnetic pole 5a can be rotated in a predetermined direction according to Flemin's left-hand rule.

Further, since the frequency detection magnetic pole 5b and the conductive pattern 8 form a frequency generator, a rotational speed signal is obtained from the output terminal (not shown) of the conductive pattern 80, and this signal is transmitted to the disk type brushless motor 1 (not shown). The disk type flangeless motor 1 can be rotated at a constant speed by controlling the speed by feeding it to the energization control circuit.

Next, referring to FIG. 3, a second embodiment of the present invention will be described. In this case, the conductive pattern 8 is not formed on the printed circuit board 7 that faces the frequency detection magnetic pole 5b, Two magnetic sensors f-13-1 and 3-2 are disposed on the surface of the printed circuit board 7 facing the frequency detection magnetic pole 5b. As the magnetic sensor 1.3-1.13-2, like the position detection element 6, a Hall element, a Hall IC,
A magnetoelectric conversion element such as an MR (magnetoresistive) element may be used. By forming a magnetic encoder with the magnetic sensor 13-1, 13-2 and the frequency detection magnetic pole 5b, a disk-type brushless motor having a frequency generator is formed. When the magnetic sensors 13-1 and 13-2 detect the substantial N and S poles of the frequency detection magnetic poles 5b, a frequency pulse signal is obtained, and the speed of the brushless motor is controlled based on this pulse signal. Just do it. The reason why two magnetic sensors 13-1 and 13-2 are used is to generate A-phase and B-phase signals conveniently for rotating the brushless motor in forward and reverse directions. If it is not necessary to rotate the magnetic sensor in forward and reverse directions, it is sufficient to use one of the magnetic sensors described above. The two magnetic sensors 13-1 and 13-2 are arranged with a phase shift in the circumferential direction by 90 electrical degrees or an angle substantially equal to this. In addition, magnetic sensor-13-1, 13-
2 on the printed circuit board 7, a through hole for storing the magnetic sensor 13-1.13-2 is provided in the printed circuit board 7, and the sensor 13-1. −
2 should be stored and arranged.

In the above example, a disk-type brushless motor has been described, but a cup-type brushless motor may also be used.Although a coreless-type brushless motor with no overlapping coils has been described, a ferrous core-type brushless motor may also be used. Furthermore, a brushless motor with overlapping coils may be used. Although the above example shows an example in which the field magnet 5 and the rotating shaft 11 are integrally formed, there is no need to limit it to this, and after forming the rotor yoke and rotor plate on the rotating shaft, Although it is okay to install Magnesoto, 1 is sufficient.

As is clear from the above, the brushless motor having a frequency generator of the present invention has (1) a built-in frequency generator;
(2) A brushless motor with good rotational balance can be obtained. (3)
(4) There is no longer a need for magnetization to form a frequency detection magnetic pole and a magnetizer for this purpose. Just by doing this, the frequency detection magnetic pole is simultaneously formed in an accurate position. (5) From the above (II to (4)), it is compact, has good rotational balance, requires less equipment, and the manufacturing process is significantly simplified. Since the magnetic pole for frequency detection can be easily formed at the correct position, it is possible to mass-produce brushless motors with high-performance frequency generators (15) at low cost.

[Brief explanation of the drawing]

Fig. 1 is a disc-type brushless motor with a frequency generator according to the first embodiment of the present invention, Fig. 2 is an exploded perspective view of the main parts of Fig. 1, and Fig. 3 is an explanatory diagram of the second embodiment of the present invention. It is. 1. Disc-type brushless motor having a frequency generator, 2. Casing, 3.. Stator armature, 4. Armature coil, 5. Field magnetic pole, 5'a. Magnetic pole for driving, 5b-' Magnetic pole for frequency detection. 6 position sensing element, 7
Printed circuit board, 8 Comb tooth-shaped conductive pattern for forming frequency generator, 13-1゜13-2...Magnetic sensor. Figure 2

Claims (8)

[Claims] (1) A magnet such as a plastic magnet is formed so as to have projections and depressions in a ring shape alternately at a fine pitch on the surface facing the stator armature, and N is applied to the surface of the magnet having the projections and depressions. 2p having S magnetic poles alternately (p is a positive integer of 1 or more)
A frequency detection magnetic pole is formed on the uneven portion of the magnet by magnetizing the driving magnetic pole of the pole, and a comb-shaped conductive pattern for forming a frequency generator is arranged opposite to the frequency detection magnetic pole. A brushless motor having a frequency generator characterized by: (2) A brushless motor having a frequency generator as set forth in claim (1), wherein the magnet is integrally formed with a rotating shaft. (3) The magnet having the uneven portion is formed integrally with the rotating shaft, and then a driving magnetic pole is magnetized and formed on the magnet surface having the uneven portion. ) A brushless motor having a frequency generator according to item (2). (4) Claim (1) characterized in that the brushless motor is a disc-type brushless motor.
A brushless motor comprising the frequency generator according to any one of items 1 to 3. (5) A magnet such as a plastic magnet is formed so as to have projections and depressions in a ring shape alternately at a fine pitch on the surface facing the stator armature, and N is applied to the surface of the magnet having the projections and depressions. 2p having S magnetic poles alternately (p is a positive integer of 1 or more)
By magnetizing and forming the drive magnetic pole of the pole, a frequency detection magnetic pole is formed on the uneven portion of the magnet, and a magnetic sensor is disposed on the stator armature surface facing the frequency detection magnetic pole. A brushless motor having a frequency generator, characterized in that a detection magnetic pole and a magnetic sensor form a magnetic encoder. (6) A brushless motor having a frequency generator as set forth in claim (5), wherein the magnet is integrally formed with a rotating shaft. (7) The magnet having the uneven portion is formed integrally with the rotating shaft, and then the driving magnetic pole is magnetized and formed on the magnet surface having the uneven portion.
) or (6). A brushless motor having a frequency generator according to item (6). (8) A brushless motor having a frequency generator according to any one of claims (5) to (power), wherein the brushless motor is a disk type brushless motor.