JP2002191146A - Gap winding motor - Google Patents

Abstract

(57) [Problem] To provide a gap winding motor that has a small loss and can reduce the number of manufacturing steps and time. SOLUTION: A stator 2 in which a stator coil 6 for forming a rotating magnetic field is mounted on an inner peripheral surface of a stator core 4 and a plurality of substantially fan-shaped permanent magnets 10 on an outer peripheral surface of the rotor core 4 are provided. And a rotor 3 disposed so as to face the stator coil 6 with a gap therebetween, and a gap is formed between the magnetic poles of the rotor core 4. Multiple slits 1
2 are provided in the radial direction to form the teeth 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless DC motor of a smooth armature winding type used in FA and OA, that is, a so-called gap winding motor, and more particularly to a structure of a rotor thereof.

[0002]

2. Description of the Related Art A gap winding motor has a stator in which a stator coil for forming a rotating magnetic field is mounted on an inner peripheral surface of a stator core, and a stator having a cylindrical rotor core made of a soft magnetic material. A plurality of substantially fan-shaped segmented permanent magnets are attached to the stator coil by bonding or the like, and a rotor is disposed so as to face the stator coil via a gap. When fixing the segment-type permanent magnet on the rotor core, high-precision fixing is required for positioning of the permanent magnet, and the assembly was performed using a jig and tool to satisfy the required accuracy. .

[0003]

However, in such a conventional gap winding motor,
There were the following problems. (1) When a permanent magnet is fixed to the surface of a conventional cylindrical rotor core made of a soft magnetic material, the magnetic gap is wide and the armature winding inductance is small. For this reason, when driven in combination with a PWM amplifier, the harmonic components included in the current waveform increase, and the loss increases. (2) When fixing segment-type permanent magnets, there is anxiety such as peeling or scattering if only adhesion is used, and it is necessary to wind glass tape etc. around the surface of the permanent magnet to prevent peeling and scattering of the permanent magnet. is there. Therefore, the number of manufacturing steps increases. (3) The positioning of the permanent magnet is very troublesome, and it takes time to manufacture. The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a gap winding motor that has a small loss and can reduce the number of manufacturing steps and time.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a stator in which a stator coil for forming a rotating magnetic field is mounted on an inner peripheral surface of a stator core, and an outer periphery of the rotor core. A plurality of substantially fan-shaped permanent magnets are attached on the surface,
And a rotor disposed so as to face the stator coil via a gap, wherein a projection is formed between magnetic poles of the rotor core, and a plurality of slits are formed in the projection. Are provided in the radial direction to form teeth. Further, in order to obtain a structure having the effect of preventing the scattering of the permanent magnet, the arc of the outer peripheral surface of the permanent magnet is formed to have a high eccentric shape at the center, and the end of the projection is formed at the end of the permanent magnet. The overhang is made, and the permanent magnet is held by the overhang portion.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front sectional view of a gap winding motor according to a first embodiment of the present invention. This embodiment shows an example of an inner rotor type gap winding motor having eight poles and six coils. In FIG. 1, reference numeral 1 denotes a gap winding motor;
And a rotor 3 rotatably supported by the stator 2 via a bearing (not shown). The stator 2 is concentratedly wound on the inner peripheral surface of a cylindrical stator core 4 formed by laminating silicon steel plates via a thin insulating layer 5 provided to secure a required withstand voltage. Six stator coils 6 for forming a rotating magnetic field are arranged at equal intervals. The stator coil 6 is connected to form eight poles, and
And is integrally fixed to the stator core 4. On the inner periphery of the resin 7, the rotor 3 is arranged concentrically with the stator 2 via a gap G.
The rotor 3 is composed of a plurality of, for example, eight rare-earth permanent magnets 10 of a segment type, for example, arranged at regular intervals and fixed to the outer peripheral surface of a rotor core 9 fitted and fixed to the outer peripheral surface of the rotating shaft 8 by bonding or the like. And constitute a magnetic pole. The rotor core 9 includes:
Recesses 11 having the same shape as the permanent magnet 10 are provided at equal intervals for the number of poles, and the permanent magnet 10 is fixed in the recess 11 by bonding or the like. The rotor core 9 is
A projection 13 is formed between the magnetic poles, and a plurality of slits 12 are provided in the projection in the radial direction to form the teeth 13. Next, the operation of the present invention will be described. When the motor is driven by a combination of the gap winding motor 1 and a PWM amplifier (not shown), current ripple occurs due to low inductance. This current ripple is P
This is due to the carrier frequency of the WM and causes an increase in loss. The ripple near the peak of the current is large. However, the current ripple can be reduced by increasing the self-inductance of the stator coil 6. Since the inductance is proportional to the square of the number of turns and inversely proportional to the magnetic resistance, the inductance can be increased by increasing the number of turns of the stator coil 6 or decreasing the magnetic resistance of the stator coil 6. Gap winding motor 1 of the present invention
Is intended to increase the self-inductance by reducing the magnetic resistance of the stator coil 6. Looking at the positional relationship between the rotor 3 and the stator 2 in FIG. 1, the center of the U-phase coil and the center of the teeth 13 face each other. In this state, the magnetic flux lines in the radial direction easily pass through due to the effect of the teeth 13 provided between the magnetic poles, but the leakage magnetic flux in the axial direction flowing directly between the permanent magnets 10 hardly passes through the teeth 13. Therefore, the magnetic resistance of the U-phase coil is minimized, and the self-inductance of the U-phase is maximized. At this time, the current value of the U-phase coil becomes maximum, so that the current ripple near the current maximum value can be reduced. [Second Embodiment] FIG. 2 is a front sectional view of a gap winding motor according to a second embodiment. In the second embodiment, the arc of the outer peripheral surface of the substantially fan-shaped permanent magnet 10 is decentered to reduce the thickness of both ends of the permanent magnet 10 in the circumferential direction, and both ends of the teeth 13 are extended in the circumferential direction. The permanent magnet 10 has a structure that overhangs to the upper surface of both ends in the circumferential direction. Thus, the permanent magnet 10 is not fixed to the rotor core 4 only by bonding, but is also mechanically held by the teeth 13, so that the permanent magnet 10 is held at three or more points including both ends. Will be. Therefore, the fixing force of the permanent magnet 10 to the rotor core 4 increases. When the fixing force of the permanent magnet 10 is strengthened, tape processing for preventing scattering of the permanent magnet 10 becomes unnecessary, and the number of manufacturing steps can be reduced.

[0006]

As described above, the present invention has the following effects. (1) In the invention of claim 1, by forming a concave portion which is a permanent magnet fixing portion in the rotor core, and forming a tooth provided with a plurality of slits in a projection portion between these magnetic pole portions, The contact area extends from the inner peripheral surface to the side surface of the segment-type permanent magnet, and the increased contact area improves the fixing force of the permanent magnet. (2) Further, since the recesses of the rotor core are formed at predetermined intervals, the positioning of the permanent magnet can be performed easily with high precision. (3) Further, since the armature winding inductance increases due to the teeth formed between the magnetic poles, carrier loss during PWM driving can be reduced. (4) In the invention of claim 2, the tips of the teeth are overhanging to the upper part of the permanent magnet, and the permanent magnet is held at three or more points including both ends of the permanent magnet,
The fixing force of the permanent magnet is improved. This eliminates the need for tape treatment as a measure to prevent the scattering of the permanent magnets, and can reduce the number of manufacturing steps.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a gap winding motor according to a first embodiment of the present invention.

FIG. 2 is a front sectional view of a gap winding motor according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gap winding motor, 2 stators, 3 rotors, 4 stator cores, 5 insulating layers, 6 stator coils, 7 resin, 8 rotating shafts, 9 stator cores, 10 permanent magnets, 11 concave portions, 12 slits, 13 Teeth, G void

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02K 21/14 H02K 21/14 M 29/00 29/00 Z F term (Reference) 5H002 AA01 AA09 AC04 AC08 AE08 5H019 AA03 AA04 CC03 CC06 CC08 5H621 BB06 BB10 5H622 AA03 CA02 CA05 CA07 CA10 CA13 CB04 CB05 PP03 PP07 PP10 PP19

Claims (2)

[Claims] 1. A stator having a stator coil for mounting a rotating magnetic field on an inner peripheral surface of a stator core, and a plurality of substantially fan-shaped permanent magnets mounted on an outer peripheral surface of the rotor core. ,
A gap winding motor having a rotor disposed so as to face the stator coil via a gap, while forming a protrusion between the magnetic poles of the rotor core,
A gap winding motor, wherein teeth are formed by providing a plurality of slits in the projection in the radial direction. 2. The arc of the outer peripheral surface of the permanent magnet has a high eccentric shape at the center, and the end of the projection is overhanged on the end of the permanent magnet, and the permanent magnet is held by the overhang. The gap winding motor according to claim 1, wherein: