JPS6013460A - Brushless motor - Google Patents

Abstract

PURPOSE:To reduce the number of the types of parts by arranging a magnet rotor of 2n-poles and 4n-poles on the same shaft to form a rotor, arranging the prescribed number of stator cores on the periphery of the rotor magnet, and switching the energization of the coils wound on the core. CONSTITUTION:A rotor 5 is composed by bonding on the same shaft 2-pole permanent magnet rotor 5a and 4-pole permanent magnet rotor 5b, and a shaft 6 is passed through the center. The core is formed by laminating the prescribed number of core pieces of substantially U-shape, and opposed to the rotor 5. Coils 9a, 9b are wound on the intermediate of U-shape of the stator. The coils 9a, 9b are sequentially switched in the energization in response to the position of the poles of the magnets 5a, 5b. This switching is performed by a circuit element 16.

Description

[Detailed description of the invention] 〔Technical field〕 This invention relates to a brushless motor.

[Background technology]

As shown in FIGS. 1 to 4, a stator 2 is arranged around a rotor 1 consisting of two poles and four poles, and a coil/l/3 m is wound around the stator 2.

3b is alternately switched by a switch 4 according to the rotational position of the rotor 1 to energize the rotor 1, thereby rotating the rotor (Japanese Patent Publication No. 58-5582).

However, in this brushless motor, the stator core 21 of the 4-pole section ta and the stator core 2b of the 2-pole section 1b have different shapes, so the number of parts increases, the structure becomes complicated, and it becomes difficult to remove the windings. , the next one has the disadvantage of poor assembly. Also 4 pole part 11! The disadvantage was that the surface area of the salient pole portion facing the pole was small, and the magnetic flux was low.

[Purpose of the invention]

Therefore, an object of the present invention is to provide a brushless motor that reduces the number of parts and is easy to assemble.

[Disclosure of the invention]

In this invention, a rotor supported between a pair of bearing stands is constructed by arranging magnet rotors of 20 poles and 40 poles on the same axis, and a substantially U-shaped stator core is arranged around the rotor magnets. A predetermined number of coils are provided, and energization of n pairs of coils wound around the stator core is sequentially switched. By arranging a predetermined number of stator cores with a roughly U-shaped shape,! '
, 2n poles, and 4n poles can be constructed from parts of the same shape, the number of parts can be reduced, the structure is simple, and the ease of assembly is improved.

As an embodiment, firstly, the U-shaped stator core O-leg ends are formed wide and arc-shaped to correspond to the rotor shape, so the area facing the rotor magnet is large and the magnetic flux is increased. do. Second, a printed circuit board with a circuit element for controlling energization of the coil is mounted on the outside of a pair of bearing pedestals, and the stator core is sandwiched between the pair of bearing pedestals.
The printed circuit board, the bearing stand, and the stator core are fixed with a fixing device (for example, a bolt) that passes through the ft-6
D, 7"! J-mount board. The bearing stand and stator core can be assembled at the same time, improving assembly efficiency.

A first embodiment of the invention is shown in FIGS. 5 to 10. That is, the rotor 5 has two pole permanent magnet rotors 5a and 4.
The permanent magnet rotor 5b of the pole is coaxially bonded and fixed through the shaft 6 in the center. The stator core 7 has a substantially U-shaped planar core piece, wide leg end portions 8, and an arcuate end surface 8a corresponding to the outer peripheral surface of the rotor 5. A predetermined number of these core pieces are stacked to form a pair of stator cores 7tx, 7b, each of which is placed opposite to each other with the rotor 5 in between, and each stator 7a, 71)
'The axial direction of the O-leg end portion 8 is positioned over the two-pole and four-pole rotors 5a and 5b of the rotor 5. In addition, there is a coil/L in the middle part of each stator 7a, 7b
/9a, 9b are wound, both ends of the stator 7 are held between a pair of bearing stands 10a, 10b, and the bearing stands 10a, 1
The printed circuit board 11 is stacked on one outer surface of the printed circuit board 11.0b. The three elements are fixed together with ports 12 and nuts 13 that pass through the bearing stands IOA, 10B and the stator cores 7A, 7B. In this case, m pedestal 10a,
10b 17) The shaft 6 of the Kirl rotor 5 is supported between the bearings 14a and 14b. 15 is a coil frame.

The printed circuit board 11 has a ring shape, and has a circuit element 16 on its surface that switches the current supply to the coils/L'9a and 9b.
has been implemented. As shown in FIG. 9, this circuit includes transistors Tr□ and Tr2 for each coil/l/9m and 9b.
A Hall element H is connected to the base of each transistor Tr and Tr2. E is a power source. A Hall element H is placed near the two-pole permanent magnet rotor 53 to detect the rotational position of the magnetic poles, and the transistors Tr, T
Turn on r2 alternately. As a result, this brushless motor can generate torque as shown in FIG. 10 (5). That is, the characteristic a is the torque generated in the two-pole rotor 531 by the excitation of the coil/L/9a, the characteristic is the torque generated by the four-pole rotor 5b, and the broken line is the torque generated by the transistor Tr depending on the position of the rotor 5.
Engineering. Tr2 is switched and coil 9b is excited. Characteristic C is the combined torque of both rotors, and is the generated torque of this monitor.

Because of this configuration, this brushless motor has less torque ripple and can be started reliably.
Since 9b is stationary, changing the voltage specification is easy.
Further, the carp/"9"*9b can be shared across the two-pole portion and the four-pole portion of the rotor 5.

Furthermore, since the stator core 7 is made of common parts, the number of parts can be reduced, ease of assembly is improved, winding is easier, and the structure is simpler. Furthermore, since the leg end portions 8 are wide, a large magnetic flux can be obtained. Furthermore, stator core 7. The bearing pedestals 1011, 10b and the printed circuit board 11 can be assembled at once, resulting in good assembly efficiency.

A second embodiment of the invention is shown in FIG. 11 and FIG. 12(6). That is, in a rotor 17 having a 2n-pole rotor 17a and a 4n-pole rotor 17b,
This is the case when n=2. In this case, the stator core 18 is also n
Pairs (18a-18d) are composed of each carp) v19a-1
The energization to 9d is sequentially switched.

FIG. 13 shows a modification thereof, in which the stator core 20 has only one pair 2011 and 20b, and n pairs of coils are wound around both legs of the stator cores 20a and 20b.

〔Effect of the invention〕

As mentioned above, according to the invention,
The stator core can be shared by the 2n-pole and 4n-pole rotors, reducing the number of parts, making it easier to wind the shared coil, making assembly easier9, and reducing costs.

[Brief explanation of drawings]

Fig. 1 is a schematic perspective view of the conventional example, Fig. 2 is its circuit diagram, Fig. 3 is a schematic cross-sectional view of the fi 4-pole part, Fig. 4 is a schematic cross-sectional view of the bipolar part, and Fig. 5 is the first example of the present invention. A cross-sectional view of the embodiment, FIG. 6 is a cross-sectional view taken along the line Vl--Vl, FIG. 7 is a cross-sectional view taken along the line ■-■ in FIG. 5, FIG. 8 is an exploded perspective view, and FIG. 9 is a coil switching circuit diagram. Fig. 10 is a torque curve diagram, Fig. 11 is a schematic sectional view of the 2n pole part of the second embodiment, Fig. 12 is a schematic sectional view of the 4n pole part, and Fig. 13 is a schematic sectional view of the 2n pole part of the modified example. It is a schematic sectional view. 5.17... Rotor, 5a... 2-pole permanent magnet rotor, 5b... 4-pole permanent magnet rotor, 7a, 7b...
- Stator core, 8... Leg end, 9a, 9b... Coil, 10a, 10b... Bearing stand, 11... Printed circuit board, 12... Bolt (fixing tool), 17a...
・2n pole rotor, 17b...4n pole rotor, 18
．． 20... Stator, 19a-19d... Coil Fig. 1 Fig. 2 Fig. 3 Fig. 4 z Fig. 5 Fig. 6 Fig. 7 Fig. 10 Fig. 11 Fig. 12 Fig. 13

Claims (1)

[Claims] rl12n (n is an integer of 1 or more) pole magnet rotor and 4n
A rotor having a pole magnet rotor disposed coaxially in the upper axial direction, a pair of bearing stands that pivotally support this rotor, and a substantially U-shaped rotor with both leg ends disposed close to each other in the upper circumferential direction of the circumferential surface of the rotor. a stator core whose axial direction of the leg end spans both rotors of the rotor and which is arranged in a predetermined number in the circumferential direction of the rotor; and n pairs of coils wound around the stator core. A brushless motor, wherein energization of the coil is sequentially switched according to the position of the magnetic pole of the magnet rotor. (2) The brushless motor according to claim (1), wherein the both leg ends of the stator core are wide and arcuate to correspond to the curved shape of the torso. (3) A printed circuit board on which a circuit element for controlling energization of the coil is mounted is arranged outside the bearing pedestal, and the stator core is sandwiched between the pair of bearing pedestals, and the printed circuit board, the bearing pedestal, and 111. A lassless motor according to claim 111, which is fixed with a fixture that passes through the stator core.