JPH06261514A - Small-sized dc brushless motor - Google Patents

Abstract

PURPOSE:To effectively utilize a remaining material at the circumferential section of a stator core as a rotor yoke member and improve the reliability of adhesion of a rotor magnet by utilizing the uneven surface of a laminated core by forming a rotor yoke section of a laminated rotor core and inner rotor by mounting and fixing the rotor magnet on and to the outer peripheral section of the laminated rotor core. CONSTITUTION:A rotor yoke 10 is formed of a laminated rotor core 11 and rotor magnets are stuck and fixed to the uneven surface of the core 11. The core 11 is formed by punching simultaneously with a stator core 5 by utilizing the remaining material of the core 5 at its inner peripheral section and a rotor yoke 10 is formed by providing a plurality of V-notches and forming a rigid mass by automatically laminating the mass in the punching die and press-fitted and tightened in the staking section 12 of a motor shaft 9. Therefore, the manufacturing cost of this brushless motor can be reduced by utilizing the remaining material at the inner peripheral section of the stator core 5 and the productivity of the motor can be improved by automatically laminating the rotor yoke 10 5 in the punching die. In addition, the reliability of the strengths of adhesion of the rotor magnets can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an inner rotor type DC
The present invention relates to a rotor yoke that is economical for a brushless motor and that can improve the reliability of adhesion of a rotor magnet.

[0002]

2. Description of the Related Art In this type of motor, the outer diameter of the rotor is large in order to obtain a large torque. In this case, a magnetic path and an inclusion (yoke) as a fastening member are required between the rotor magnet and the shaft. For forming the rotor yoke, (1) a method of making the magnet extremely thick and (2) a method of making the motor shaft diameter of the magnet pasting portion extremely thick are possible. Conventionally, in the rotor of this type, the latter method (2) is used. Has been used. In the method of (1), the magnet is expensive, and there is a difficulty in magnetic field orientation (particles are aligned in one direction by magnetic force). In the method of (2), the shaft is cut from a thick material, which is also expensive. In addition, in (1) and (2), the inner peripheral portion of the punched stator core was not usable, and material loss occurred such that it was discarded.

[0003]

According to the present invention, in the prior art, since the rotor yoke portion is formed by making a part of the motor shaft thick, the motor shaft is an expensive and uneconomical part. In addition to supplying an economical motor shaft, effectively utilizing the residual material of the circumference of the stator core, which has been conventionally scrapped, for the rotor yoke member, and improving the bonding reliability of the rotor magnet by utilizing the unevenness peculiar to the laminated core. For the purpose of further improving the workability of assembling the rotor yoke into the rotor, the rotor core is a laminated solid body (non-stacked). In large motors, the cores can be agglomerated by bolting, but in small motors such as the present invention,
The bolt tightening method is difficult because of dimensional and magnetic path problems.

[0004]

In order to achieve the above-mentioned object, the rotor magnet inner peripheral side rotor yoke portion is formed of a laminated rotor core, and the motor shaft has no large diameter portion,
A so-called approximate straight type shaft was used.

In the rotor core forming the rotor yoke, the inner peripheral portion of the stator core is removed simultaneously with the stator core,
A V notch for lamination was provided, and an automatic lamination shape was formed in a press punching die to form a one-piece rigid body, and a motor shaft was press-fitted and fastened thereto. Furthermore, the rotor magnet was adhesively fixed to the uneven surface generated when the cores were laminated.

[0006]

The laminated rotor core provided on the inner peripheral portion of the field magnet is used as a yoke to form the field magnetic path of the motor together with the stator core. Since the rotor core is formed of the same electromagnetic steel plate as the stator core, compared to a rotor yoke formed of a structural carbon steel motor shaft,
High magnetic permeability increases the amount of magnetic flux to obtain a highly efficient motor.

Further, since the rotor magnet peculiar to the inner rotor type brushless motor is adhered to the surface having irregularities peculiar to the laminated core, a wedge-shaped void (10 to 20 μm which is optimum for adhesion) of the adhesive is formed. A highly reliable adhesive fastening can be obtained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An inner rotor type small DC brushless motor according to the present invention will be described with reference to FIGS. The structure of a conventional brushless motor is shown in FIG.

FIG. 5 shows an in-mold automatic laminating system for rotor cores.

The laminated rotor core 11 according to the present invention is press-fitted and fixed to the motor shaft 9, the field rotor magnet 6 is adhesively fixed to the outer peripheral portion of the laminated rotor core 11, and the relative position of the rotor magnet 6 is fixed. The position detection magnet 1 is attached to one end of the motor shaft 9 to form a rotor 14. The rotor magnet 6 is provided with an air gap on the outer periphery thereof, the stator 15 formed by winding the coils 7 around the laminated stator core 5 in multiple phases, the housing 4, the end brackets 3 and 8 forming the frame, and the position detection magnet 1 The Hall element 13 is provided at the opposite position. The magnetic flux emitted from the rotor magnet 6 is
A magnetic path is formed between the rotor yokes 10 via the stator 15. An electric current is applied to the coil 7 wound around the stator core 5 from the outside to generate torque between the rotor magnets 6. Rotor magnet 6 by the Hall element 13
Is detected, and according to the detected position, the multi-phase wound coil 7 is energized in sequence in order to obtain rotation in a fixed direction.

In the present invention, as shown in FIGS. 1 to 3, the rotor yoke 10 is formed by the laminated rotor core 11. Also, the rotor magnet 6 is as shown in FIG.
It is adhered and fixed to the rotor core laminated uneven surface 17.

The rotor core 11 according to the present invention is stamped at the same time as the stator core 5 and has a plurality of V notches 16 using the residual material of the inner peripheral portion of the stator core 5. The rotor yoke 10 is formed into a rigid body.

The rotor yoke 10 is press-fitted and fastened to the staking portion 12 provided on the motor shaft 9.

[0014]

According to the present invention, it is possible to effectively utilize the residual material of the inner peripheral portion of the stator core and to reduce the manufacturing cost of the motor shaft by about half. Further, since the rotor yoke according to the present invention becomes a one-piece rigid body by the in-mold automatic laminating method, the work of press-fitting into the motor shaft and the handling of parts are facilitated, and the bonding strength and reliability of the rotor magnet are improved.

Further, the use of the electromagnetic steel plate made of the same material as the stator core has a ripple effect of increasing the electric efficiency of the motor.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of an inner rotor type DC brushless motor according to the present invention.

FIG. 2 is a perspective view of a stator core and a rotor core showing an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing adhesive fixing of a laminated rotor core and a rotor magnet.

FIG. 4 is a sectional view showing a structure of a conventional inner rotor type DC brushless motor.

FIG. 5 is a sectional view showing an in-mold automatic laminating press system of a rotor core.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Position detection magnet, 2 ... Detector cover, 3 ... End bracket (1), 4 ... Housing, 5 ... Laminated stator core, 6 ... Rotor magnet, 7 ... Coil, 8 ... End bracket (2), 9 ... Motor shaft DESCRIPTION OF SYMBOLS 10 ... Rotor yoke, 11 ... Laminated rotor core, 12 ... Staking, 13 ... Hall element, 14 ... Rotor, 15 ... Stator, 16 ... Laminating V notch, 17 ... Rotor core lamination uneven surface, 18 ... Adhesive, 19 ... Shaft Large diameter part, 20 ... Punch, 21 ... Die, 22 ... Plate, 23 ... Core material, 2
4 ... Square hole for stack separation.

Claims (4)

[Claims] 1. An inner rotor type small DC brushless motor having a magnet on the rotor side, wherein the rotor yoke portion is formed of a laminated rotor core, and the inner rotor is formed by mounting and fixing the rotor magnet on the outer peripheral portion thereof. A small DC brushless motor that does. 2. The rotor core according to claim 1, wherein the rotor core is simultaneously punched with the stator core and has a plurality of V-shaped notches for lamination, and is automatically laminated in a press punching die, which is a solid body which is advantageous for handling and assembling. Small DC characterized by
Brushless motor. 3. A compact DC brushless motor according to claim 1, wherein an uneven surface generated when laminating the rotor core is used to improve the bonding strength and reliability of the rotor magnet. 4. The small DC brushless motor according to claim 1, wherein the laminated core is press-fitted and fastened by staking (partial linear protrusions) provided on a motor shaft.