JPS59139849A - Disk type brushless motor - Google Patents

Abstract

PURPOSE:To inexpensively simplify the structure of a disk type brushless motor by arranging a printed board provided with a conductive pattern coil for detecting the rotating speed at the stationary side position opposed to a magnet for detecting the rotating speed and providing a magnetically levitating magnet on the lower surface of the board. CONSTITUTION:A field magnet 15 for driving a rotor is disposed oppositely to a stator armature having an armature coil 14. A magnet 11 for detecting the rotating speed is provided on the outer periphery of the magnet 15. A printed board 13 provided with a conductive pattern coil for detecting the rotating speed is arranged at the stationary side position opposed to the magnet 11, and a magnetically levitating magnet 18 is provided on the lower surface of the board.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention enables mass production at low cost by preventing armature coil groups from overlapping each other, and furthermore, provides electric components such as magnetic sensing elements and drive circuits on the stator armature side. It is possible to create a disk-type brushless motor that is extremely flat in the axial direction, and the initial shape of the armature coil can be maintained without making it stronger with plastic molding, etc., and the durability can be extended. The present invention relates to a disk-type brushless motor that has been devised to enable low-cost mass production of disk-type brushless (DC) fan motors using the motor having the above characteristics. Furthermore, the disk-type brushless motor can reduce the load on the rotor, which allows for smooth rotation, and has a built-in rotational speed detection mechanism, making it possible to obtain a very compact brushless motor. Regarding.

Recently, disc-type commutator motors have been used in small cassette tape recorders and the like, and their useful value has been discovered. However, it is well known that brushless motors have better performance than commutator motors in terms of life and other aspects. Here, obtaining a disk-type brushless motor has many advantages in terms of energy saving policy, but it is desirable to be able to rationally incorporate electrical and electrical components for a drive circuit for driving the motor.

However, there have not been many motors devised in this way in the past, and furthermore, there are no motors like the disk-type brushless motor of the present invention, which will become clear below. Additionally, if the above electrical components are incorporated into a conventional disk-type brushless motor, the air gap formed by the field magnet and armature coil will also increase, making it impossible to obtain strong torque and resulting in a highly efficient motor. It has its drawbacks. In addition, a disc-type brushless motor must be compact, mass-produced at low cost, and have high performance. Furthermore, it would be desirable to be able to use it as a main component of a disk-type brushless fan motor by being compact and compact.

However, the disk-type brushless fan motor that has recently appeared uses a core (iron core) for winding the armature coil.
Because of this, it is difficult to obtain a disk-shaped disk that is extremely flat in the axial direction, making it expensive. In addition, due to this configuration, there is not enough space to incorporate electric circuit components such as the necessary drive circuit, so it is necessary to use a disc-type brushless human motor with a thickness (5) in the axial direction. .

In addition, disc-type brushless fan motors are often used to cool computers, etc., and if the rotation speed of the disc-type brushless fan motor stops for some reason, the heat generated by the rotation of the motor will be used to cool the computer, etc. A situation occurs in which a malfunction occurs. Therefore, at present, it is possible to detect the rotational speed of a disk-type planless fan motor (not necessarily limited to disk-type ones), and detect the rotational speed of a disk-type brushless fan motor (although most conventional disk-type brushless fan motors are AC motors). It is.

However, recently, a direct current disk type brushless fan motor has been desired. Therefore, the fan motor of the present invention is a DC disc type brushless fan motor. ) when the rotation speed of the computer falls below a certain value, the lightning source of the computer etc. is automatically turned off, protecting the computer etc.

However, the conventional disc-type brushless 7-arm motor (6) is not equipped with a rotational speed detection mechanism, and requires the use of a separate tacho generator and encoder.
The equipment was made to be extremely expensive.

Furthermore, in the case of a disc type brushless fan motor,
Due to the need to blow air, the load on the rotor inevitably increases,
There was a tendency for performance to deteriorate compared to when the load was square.

The present invention was made to solve the above-mentioned conventional drawbacks, and the rotor has 2P (P) having N and S magnetic poles alternately.
is a positive integer of 2 or more) having a rotor driving field magnet facing the stator armature, and an N or S pole rotation speed detection magnet provided on the outer periphery of the field magnet. A strongly magnetized part and a weakly magnetized part of N or 8 poles are formed alternately at a fine pitch on the surface of the rotational speed detection magnet facing the stator armature, and a comb is formed at a fixed side position facing the rotational speed detection magnet. A disk type, characterized in that a printed circuit board is provided with a tooth-shaped conductive, turn-by-turn coil for detecting rotational speed, and a magnetic levitation magnet having the same polarity as the magnet for detecting rotational speed is provided on the lower surface of the printed circuit board. In addition to obtaining a brushless motor, an extremely thin disk-type brushless motor that allows electric circuit parts to be rationally incorporated, and a structure that is simple and suitable for mass production at low cost, as well as a similar device as described above using this motor. This makes it possible to obtain an effective disc-type brushless fan motor.

An embodiment of the present invention will be described below with reference to the drawings.

Mainly referring to FIG. 1, a disc-type brushless motor M as an embodiment of the present invention will be described. The main body of the disc-type brushless motor M, as shown by reference numeral 1, is
A large space 1 is obtained.

This means that the axial thickness of the space 1 can be reduced, and if the axial thickness of the space 1 is reduced,
This means that a disk-type brushless motor M that is extremely flat in the axial direction or a disk-type brushless fan motor to which this motor is applied can be obtained. Further, by utilizing this space 1, various electric circuit components can be built in, which means that the disk-type brushless motor M and a high-performance disk-type brushless fan motor to which this motor M is applied can be obtained. The cup body 2 is on the fixed side and has a central through hole 3, and the inner circumference of the through hole 3 has a protrusion 2a extending upward. The cylindrical body 4 is attached to the inner peripheral portion of the central through hole 3 formed by the protruding body 2a. The bearing 5 is formed on the inner circumference of the cylindrical body 4. The rotating shaft 6 is rotatably supported by a bearing 5,
It is erected vertically on the cup body 2. E IJ 7 is
It is attached to the lower end of the rotating shaft 6. The disc-shaped magnetic yoke 8 has four parts 9 at the upper surface position, which will be described later, and has a protruding body 2.
It is supported horizontally by the top surface of the protrusion 2a, and is fixed to the protrusion 2a in that position by means such as screws 10 or adhesive. When this magnetic yoke 8 is formed using magnetic powder, such as iron powder, and non-magnetic powder, such as plastic powder, as main raw materials, the performance of the disc-type brushless motor M of the present invention can be improved (9). It is also convenient for mass production.

A printed wiring board 17 having a planar arc shape as shown in FIG. A gap is formed at the bottom of the recess 9. code 1
9 is a through hole formed approximately at the center of the magnetic yoke 8. On the upper surface of the printed wiring board 17, there are three magnetic sensing elements 19-1.・・・・・・
・,]]'-1-3 and electric circuit components 20 (resistors) and 21 (transistors) constituting a motor drive circuit are arranged, and the solder connection terminals 22 of the element 19 group and the electric circuit components 21 are arranged. By facing the recess 9, the terminals 22 can be rationally processed.

The upper end of the rotating shaft 6 is fixed to a boss fixed to a substantially central through hole of an annular magnetic yoke 23. An axially flat cup body Z5 made of plastic is fixed to the upper surface of the magnetic yoke by appropriate means. On the surface of the magnetic yoke B facing the armature coil 14, as shown in FIG. is permanently installed.

Note that the reference numeral 26 is a winding frame made of plastic, and the reference numeral 27 is a screw. An N pole (
An annular rotational speed detection magnet 11 (or SwL may be used) is fixedly installed. On the surface of the rotational speed detection magnet 11 facing the stator armature made up of the armature coils 14, there are strongly magnetized N poles (N poles) with fine pitches.
or S pole) and the weakly magnetized part N' pole (or S
On the upper surface of the stator armature, which is the opposite stator side pole, is fixed a printed circuit board 13 on which (a conductive/zip-turn coil for detecting rotational speed in a tooth shape) 2 is formed. The armature coil I4 is prevented from being damaged by providing the printed circuit board] 3. That is, the armature coil 14, the magnetic sensing element 19-1..., 19-
3 and the electric circuit components 31 and 21 are protected by the printed circuit board 13, the armature coil 14 is
Shape damage, armature coil 14, magnetic sensing element +9-1
．． ......, 19-3 and electric circuit component 7f1,
210 solder can be prevented from coming off, and the durable life of the motor M can be extended. Therefore, it is very useful in terms of quality control. The pitch of the conductive turn coil 12 is the strongly magnetized portion N of the rotation speed detection magnet) 11.
It is the same as the pitch of the pole and the weakly magnetized part N' pole. Conductivity/
Every other line segment in the radial direction of the turn coil 12 is
For example, when facing the strongly magnetized part N11i, the group of line segments between these faces the weakly magnetized part N' pole.Thereby, each line segment has a magnet for rotational speed detection) 110 that corresponds to the same polarity according to the rotational speed. An electromotive force is generated in the direction, and a detection output of a frequency corresponding to the rotational speed of the rotor is obtained from the output terminal 12a of the conductive magnet coil 12.

Incidentally, although the magnetic flux generated by the rotational speed detection magnet 11 appears intermittently,
2 are formed all around the circumference as shown in FIG. 5, so the detection output is obtained as a continuous wave. In addition, even if there is pitch unevenness in the rotational speed detection magnet (IIK), the pitch unevenness is averaged out by the comb-shaped conductors of the plurality of conductive magnet coils 12, and a constant frequency can be detected when the rotor rotational speed is constant. I get the output. The fluctuations in the low and evening speeds are extracted as frequency modulation components of the detection output.

Therefore, the rotor, that is, the disc type brushless motor M
You can know the rotation speed of.

The lower surface of the printed circuit board 13 facing the rotational speed detection magnet 11 is provided with the rotational speed detection magnet 11.
] An annular magnetic levitation magnet 18 is fixedly installed with the north pole facing the same pole (that is, the north pole). Therefore, the rotor consisting of the field magnet 15 and the like rotates without being subjected to any unnecessary load. Further, since the bearing 5 is not subjected to the self-phase, a longer life of the product can be expected, and a disk-type brushless motor M that rotates smoothly can be obtained. This provides a very important advantage when used as a disc-type brushless fan motor.

(13) FIG. 6 shows a developed view of the field magnet 15 and the armature coil 14, and using this FIG. 6, the magnetic sensing element 19-1. ..., +9-3 will be explained below. Referring to FIG. 6, three armature coils 14-1. . . . , 14-3 are arranged in close plane so as not to overlap each other, and the field magnets 1
Element 19 groups and electric circuit components 2 are placed on the fixed side surface facing 5.
It shows that there is a space name in which fl, 21 can be placed. Armature coil 14-1°...
..., the negative terminals of each of 14-3 are now connected to a semiconductor rectifier (motor drive circuit) 29 constituted by electric circuit components 2fl, 2], and the other terminals of each are commonly connected. ing. Code 30-1, 30
-2 are a positive power terminal and a negative power terminal, respectively. Each armature coil 14-1. ．． ......, 14
-3 magnetic sensing element]'-1-1,...
, 19-3 are connected to a semiconductor rectifier 29. Magnetoelectric conversion element 1.9-1. ......, 1
9-3 is an armature coil 14-1. which faces the field magnet 15 in a plane. . . ., on the conductor portion 14a or ]4a' which contributes to the generated torque of 14-3, for example (14), it is desirable to arrange it at the dotted line enclosure portion 3 (1, 31, 32 positions. , magnetoelectric transducer +44-1.
.......

19-3, the air gap between the field magnet 15 and the armature coil 14 increases by the thickness of the element 1q, making it impossible to obtain a stronger rotational torque. Therefore, the above element 19-1,...
, 19-3 is at the same position as the conductor parts 14a, 14a' and outside the conductor parts 14a, 14a', for example, on the dotted line enclosure side'.

31' and 32', and are arranged as shown in FIG. In order to utilize the disk-type brushless motor M thus formed as a disk-type brushless fan motor, as shown in FIG.
The above-mentioned fan 3 is fixed to the top surface of the
3. Either a fan similar to 3 may be formed, or a fan-equipped cup body 34 may be used instead of the cup body 5. For example, as shown in FIG.
It would be better to have it built-in and fixed inside.

In addition, in the above example, the field magnet I5 is as follows:
Although the case of 2P (P=3) poles having alternating N and S magnetic poles has been described as an example, it goes without saying that a positive integer pole of P=2.4 or more may also be used. In addition, the field magnet 15 may be magnetized in a skew manner, or the conductor portions 14a, 1 which contribute to the torque generated by the armature coil 14 may be used.
It goes without saying that the present invention is also applicable to a structure in which 4a' is wound in a skew manner. This means that the rotation speed detection magnetic pole 1
The same applies to 8 and the conductive turn coil 12.

Since the disk-type brushless motor of the present invention has the above-mentioned configuration, the armature coil, position detection element, electrical components, and rotational speed detection mechanism are provided on the fixed side surface facing the field magnet forming the component of the rotor. Even if it is installed, the above elements and electric circuit parts do not increase the air gap between the armature coil and the field magnet, so strong rotational torque can be obtained, and since it is a magnetically levitated type, it is highly efficient. A small disk-type brushless motor or disk-type brushless fan motor that rotates smoothly can be obtained, which has the effect of contributing to energy-saving policies.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a disc-type brushless motor as an embodiment of the present invention, Fig. 2 is a perspective view of the stator armature, Fig. 3 is a plan view of the field magnet, and Fig. 4 is rotational speed detection. FIG. 5 is a plan view of a printed circuit board on which a conductive ξ-turn coil for rotational speed detection is formed, and FIG. 6 is a developed view of the armature and field magnet. FIG. 7 is a perspective view of a cup body with a fan, and FIG. 8 is a perspective view of a main body for forming a disc type brushless fan motor. M...Disk type brushless motor, 1...Space, 2...Cup body, 2a...Protrusion body, 3...Center hole, 4...Cylindrical body, 5... Bearing, 6... Rotating shaft, 7... EIJ ring, 8; Storage key... Magnetic yoke, 9... Recess, 10... Screw, 1]... Rotating speed detection magnet , (J7) 12... Conductive A-turn coil for rotational speed detection, 12m
...Output terminal, 13...Printed circuit board, 14...
Armature coil, 15... Field magnet, 16...
Stepped portion, 17...Printed wiring board, 18...Magnetic levitation magnet, ]9-1. ......, 19-3
...magnetic sensing element, mosquito, 21...electric circuit component, z
2... Soldered connection terminal, device... magnetic yoke, separate...
...Guess, δ...Cup body, 26...Reel frame, 27.
...screw, public space, 29...semiconductor rectifier (motor drive circuit), add-1...positive power terminal,
30-2... Negative power supply terminal, (9), 31,
32, 30', 31', 32'... Dotted line surrounding portion, 33... Fan, 34... Cup body with fan, 3
5... Through hole, groove... Main body for forming a disc-type brushless fan motor, 37... Recessed portion. (!8)

Claims (1)

[Scope of Claims] 1. A field magnet for rotor driving having 2. P (P is a positive integer of 2 or more) poles and having N and S magnetic poles alternately facing the stator armature is provided; A rotational speed detection magnet with an N or S pole is provided on the outer periphery of the field magnet, and a strongly magnetized part and a weakly magnetized part with an N or S pole are arranged at fine pitches on the surface of the rotational speed detection magnet that faces the stator armature. A printed circuit board is provided on the fixed side opposite to the rotational speed detection magnet, and a comb-like conductive cross-turn coil for rotational speed detection is provided on the lower surface of the printed circuit board. A disk-type brushless motor characterized by having a magnetic levitation magnet with the same polarity as the detection magnet. 2. A flat annular rotor drive field magnet with 2P (P is a positive integer of 2 or more) poles, which has alternating north and south magnetic poles, is hung on the rotating shaft that is rotatably supported. A printed circuit board is provided at a fixed side position facing the field magnet, and the printed circuit board is wound so that the opening angle of the conductor portion that contributes to the generated torque is approximately equal to the magnetic pole width of the rotor driving field magnet. The armature coils are arranged so that two or more armature coils are not overlapped, and one or more magnetic sensing elements are arranged on the printed circuit board surface at a position outside the conductor part that is in an equal relationship with the conductor part that contributes to the generated torque of the armature coil. electrical components such as a drive circuit are arranged on the printed circuit board surface outside the position occupied by the armature coil, and a magnetic yoke having a notch is provided on the lower surface of the armature coil to connect the terminals of the electrical components, etc. 2. The disc-type brushless motor according to claim 1, wherein the disc-type brushless motor faces the notch. 3. The number of the chamber armature coils can be arranged so as not to overlap with each other on the surface of the printed circuit board, and the number of the above-mentioned electric components or even a magnetic sensing element can be arranged. The disc-type brushless motor according to item 1 or 2. 4. The disk type according to claim 3, wherein the number of armature coils is one m (m is a positive integer of 2 or 3) the number of magnetic poles of the field magnet. brushless motor. 5. The above-mentioned magnetic sensing element and the above-mentioned lightning and gas components are disposed on the printed circuit board surface so that the height is approximately equal to or less than the thickness of the armature coil. A disc-type brushless motor according to any one of the ranges 1 to 4.