JPH0365041A - Brushless motor - Google Patents

Abstract

PURPOSE:To simplify the assembling process by sticking a flexible substrate, printed with a copper pattern, to the inner circumferential face at stator yoke section. CONSTITUTION:A brushless motor for magnetropneumatic bearing type deflector comprises a rotor magnet 16 to be fitted onto a hollow rotary shaft 11, a fixed shaft 17, a base 20, a casing 21 and an upper cover section 22, a stator yoke section 30, and the like. The stator yoke section 30 is constructed such that a winding coil section 31, where a copper pattern 31b is printed onto a flexible substrate 31a, is stuck onto the inner circumferential face of the hollow cylindrical yoke section 30. By such arrangement, assembling process is simplified and cogging torque or wind loss can be suppressed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides an inner rotor suitable for an air magnetic bearing type optical deflector (polygon scanner) used as a laser beam writing system of a laser printer, digital copying machine, etc. Regarding type brushless motors.

[Conventional technology]

FIG. 4 shows a conventional air-magnetic bearing type optical deflector incorporating a brushless motor, in which reference numeral 11 denotes a hollow rotating shaft, with a magnet holder 12 screwed onto the upper part thereof. A magnet (permanent magnet) 13 is fixed. ll
Reference character a denotes a rotating shaft flange, and a polygon mirror 15 fitted onto the hollow rotating shaft 11 is clamped and fixed between the rotating shaft flange 11a and the mirror holder 14. 16 is a hollow rotating shaft 11
The rotor magnet is fitted onto the outside of the rotor, and together they constitute a rotating body.

The fixed shaft 17 to which the hollow rotating shaft 11 is fitted also has a magnet 19 fixed to a magnet holding portion 18 at the upper end.

Further, the lower end portion is firmly fixed to the base 20 by a method such as press-fitting or shrink-fitting. Furthermore, a herringbone groove 17 is formed on the surface of the fixed shaft 17 to configure a dynamic pressure bearing.
It has two upper and lower pairs of a and 17b.

When the rotating body starts rotating, the pressure in the gap between the rotating shaft 11 and the fixed shaft 17 increases, forming a dynamic pressure bearing and supporting the rotating body without contact.

On the other hand, the thrust magnetic bearing is composed of magnets 13, 19, 23 at the upper end of the rotating shaft 11, the upper end of the fixed shaft 17, and the upper cover 22 of the case 21.

The magnetic poles of the magnets are such that the surfaces facing each other have the same polarity, and the magnet 13
is repelled from above and below, floating the rotating body and supporting it without contact.

On the other hand, the brushless motor is of the inner rotor type, and is composed of a rotor magnet 16, a slot iron core 24, a coil 25, and a Hall element 26.

FIG. 5 is a cross-sectional view of a conventional brushless motor, in which the rotor magnet 16 is located at the edge portion 2 of the slotted iron core 24.
The coil 25 is loosely fitted inside the slotted core 24, and the coil 25 is wound around a coil winding portion 24b formed protruding inside the slotted iron core 24, and is secured to the edge portion 24a. Reference numeral 27 denotes a gap between the coiled portions 24b and 24b having an edge portion 24a formed at the tip.

[Problem to be solved by the invention]

The above-mentioned conventional technology requires a step of winding the coil 25 around the slotted iron core 24 (the coil winding portion 24b thereof), and a step of connecting and bonding each coil, resulting in a problem that the work is time-consuming and the assembly is complicated. Ta.

In addition, since the slotted iron core 24 is used, unnecessary voids 27 are created, and when rotating at extremely high speeds, turbulence is further generated at the edge portion 24a, resulting in large windage loss, resulting in noise and heat generation. There was a problem with waking up.

An object of the present invention is to provide a brushless motor that simplifies the assembly process, reduces cogging torque, windage loss, and iron loss, and can rotate with high precision.

[Means to solve the problem]

The above purpose is to provide a winding coil part with a winding coil-shaped copper pattern printed on a flexible substrate, a hollow cylindrical stator yoke part with this winding coil part attached to the inner peripheral surface,
This is achieved by including a rotor magnet loosely fitted inside the stator yoke portion.

[Effect]

A flexible substrate printed with a copper pattern is attached to the inner circumferential surface of the stator yoke section, thereby forming a coil section that corresponds to the internal rotor magnet, making the assembly process extremely simple and reducing cogging torque due to the slotted iron core. , windage damage, etc. can be suppressed.

〔Example〕

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

Note that the same parts as in the conventional example are given the same reference numerals, and redundant explanations are omitted.

FIG. 1 is a longitudinal sectional view of an air-magnetic bearing type optical deflector incorporating a brushless motor according to the present invention, in which 30 is a stator yoke portion and 3 is a winding coil portion. The rotor magnet 16 is loosely fitted onto the inner circumferential surface of the wire-wound coil portion 31.

FIG. 2 is a perspective view of the stator yoke portion, and FIG. 3 is a developed view of the winding coil portion. As shown in FIG. 2, the hollow cylindrical stator yoke portion 30 has a flexible A wire-wound coil portion 3I on which a copper pattern 31b is printed is pasted on the substrate 3ia.

Note that the material of the stator yoke portion 30 may be a laminated silicon steel plate or a soft magnetic material.

As shown in FIG. 3, the copper pattern 31b is printed on the flexible substrate 31a in the shape of a wire-wound coil. Further, a Hall element 31c is provided at the center of each copper pattern 31b, and an electrode portion 31d is further formed at the end of each copper pattern 31b.

Note that the number of phases, number of poles, number of coils, etc. of the motor can be set arbitrarily.

Since the stator yoke section 30 and the winding coil section 31 have such a structure, the assembly process is greatly simplified, and there is no wasted space, making it possible to save space. Furthermore, since there is no slotted iron core, no cogging torque is generated, making it suitable for polygon scanners that require constant rotation, and a brushless motor with no turbulence and low loss can be realized.

Particularly in an ultra-high-speed brushless motor, the number of turns of the coil can be reduced depending on how it is designed, so the copper pattern 31b as in this embodiment is convenient.

Furthermore, even though it is a coreless type, it is possible to shorten the gap and increase motor efficiency. Furthermore, since the stator yoke portion is made of a cylindrical magnetic material, the magnetic path length of the rotating magnetic field is shorter than in the case of a slotted core, and iron loss is reduced.

〔Effect of the invention〕

As explained above, according to the present invention, the coil part of the brushless motor is formed by pasting a flexible substrate with a copper pattern printed on the inner peripheral surface of the stator yoke part. (1) Assembly of the winding part The process is simplified and the number of parts is small, making it possible to make it more compact. (2) No cogging torque is generated and high-precision rotation is possible. (3) There is no slotted iron core, so there is low loss and low It is possible to provide a brushless motor that can reduce noise.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an air magnetic bearing type optical deflector incorporating a brushless motor according to the present invention, FIG. 2 is a perspective view of a stator yoke, and FIG. 3 is a winding. FIG. 3 is a cross-sectional view of the motor. 16... Rotor magnet, 30... Stator yoke part,
31... Winding coil portion, 31a... Flexible board, 31b... Copper pattern. Figure 3 31 Figure 4

Claims (1)

[Claims] A winding coil part with a winding coil-shaped copper pattern printed on a flexible substrate, a hollow cylindrical stator yoke part with this winding coil part attached to the inner peripheral surface, and a free space inside this stator yoke part. A brushless motor characterized by comprising a rotor magnet fitted into the motor.