JP2000209801A - Structure of brushless motor coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce difference of heat generation due to the difference of application frequency to improve operation life and reliability by introducing a structure where the diameter of lead wire of the internal coil and external coil is different with each other. SOLUTION: In this brushless motor, an intermediate terminal U1 is connected at the intermediate position between the internal coil 10b and external coil 10c of the U-phase coil 10, an intermediate terminal V1 to the intermediate position between the internal coil 11b and external coil 11c of the V-phase coil 11 and an intermediate terminal W1 is connected at the intermediate position between the internal coil 12b and external coil 12c of the W-phase coil 12c. The diameter of lead wire of the internal coils 10b, 11b, 12b and the diameter of lead wire of the external coils 10c, 11c, 12c are different with each other to equalize heat generation of the internal coils 10b, 11b, 12b and external coils 10c, 11c, 12c during the power feeding. Accordingly, difference of heat generation due to the application frequency can be reduced as much as possible to prevent generation of stress at the particular portion. Thereby, insulation failure and break of lead wire can be prevented to attain improvement of reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a winding structure for a brushless motor, and more particularly, to a heat generation difference due to a difference in frequency of use by changing the wire diameters of inner and outer windings of a plurality of stator windings. And to improve the life and reliability.

[0002]

2. Description of the Related Art Conventionally, as a winding structure for a brushless motor of this type which has been used, in the case of a brushless motor requiring high stall torque and high speed rotation, windings of each phase are formed by an inner winding and an outer winding. It is divided into lines, and switching between partial energization and overall energization is performed.

[0003]

The conventional winding structure for a brushless motor has the following problems because it is configured as described above. In other words, the inner winding of each phase winding has a higher use frequency than the outer winding, so that thermal stress is easily generated, which causes failure such as poor insulation or disconnection.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in particular, the wire diameter of the inner winding and the outer winding of the multi-phase stator windings are made different from each other so that the difference in the frequency of use is reduced. It is an object of the present invention to provide a winding structure for a brushless motor in which a difference in heat generation due to heat is reduced and life and reliability are improved.

[0005]

SUMMARY OF THE INVENTION A winding structure for a brushless motor according to the present invention uses a multi-phase stator winding having one end connected to a middle point and each having another end, and is provided at a position halfway between the stator windings. In the winding structure for a brushless motor, an intermediate terminal is provided, and energization to an inner winding between the middle point and each intermediate terminal and an outer winding between each intermediate terminal and the other end can be selected. And the outer winding has a different wire diameter, and the inner winding has a larger diameter than the outer winding.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a winding structure for a brushless motor according to the present invention will be described below with reference to the drawings. FIG. 1 shows a three-phase brushless motor winding composed of U, V, and W phases. In FIG. 1, a reference numeral N denotes a U-phase winding 10 and a V-phase winding 11 which constitute a stator winding. And one end 10a, 11a, 1 of W-phase winding 12
2a is a middle point connected in common, and each of these windings 1
0, 11, and 12 are the inner windings 10 on the side near the midpoint N.
b, 11b, and 12b, and outer windings 10c, 11c, and 12c farther from the middle point N.
d, 11d, and 12d are configured to be independently connectable.

An intermediate terminal U1 is connected at an intermediate position between the inner winding 10b and the outer winding 10c of the U-phase winding 10, and the inner winding 11b and the outer winding 11 of the V-phase winding 11 are connected.
The intermediate terminal V1 is connected to an intermediate position between the inner winding 12b and the outer winding 12c of the W-phase winding 12, and an intermediate terminal W1 is connected to an intermediate position between the inner winding 12b and the outer winding 12c of the W-phase winding 12. In addition,
The intermediate terminals U1, V1, and W1 may be located at half the position of the winding, or may be located at any position other than 1/2.

Since the windings 10, 11, and 12 are driven in three phases, they are driven for each of the U, V, and W phases. However, depending on the driving method of the motor, the inner windings 10b,
Driving is performed by exciting only or all of 11b and 12b. Therefore, the wire diameter of each of the inner windings 10b, 11b, and 12b and the wire diameter of each of the outer windings 10c, 11c, and 12c are made different from each other, so that each of the inner windings 10b, 11c when energized.
The heat generation of b, 12b and each of the outer windings 10c, 11c, 12c is leveled so that the difference in heat generation due to the difference in use frequency is minimized, thereby preventing the occurrence of stress in a specific portion.

That is, U1, V1, W1 in FIG.
And N, the time passed between t ₁ and the current I ₁ , U 2, V
2, assuming that the time passed between W2 and N is t ₂ and the current is I ₂ , the heat generation of the coil between U1, V1, W1 and N is (I
^{_{1 2 × t 1 + I 2}} 2 × t 2) × R 1, U2, V2, heat generation of the coil between W2 and N is ^{_{I 2 2 × t 2 × R}} 2. In this case, in the conventional configuration, since the wire diameters φD1, φD2 of the inner windings 10b, 11b, 12b and the outer windings 10c, 11c, 12c are the same, if only one of them is frequently energized and driven, the balance of heat generation can be obtained. not, had changed the number of turns, in the present _{invention, R 2 = R 1 + (} I 1 2 × t 1 / I 2 2 × t 2) × close so as to wire diameter in R ₁ .phi.D1, selecting φD2 Thereby, the heat generation is leveled. The inner winding 10b,
If the inner windings 10b, 11b, and 12b are driven more frequently, the wire diameter of the inner windings 10b, 11b, and 12b is increased, and φD1
> ΦD2 can be achieved by lowering the resistance.

[0010]

Since the winding structure for a brushless motor according to the present invention is constructed as described above, the following effects can be obtained. That is, by making the wire diameters of the inner winding and the outer winding of each phase winding different from each other,
The difference in heat generation due to the difference in usage frequency can be reduced, the bias of stress to a specific portion can be prevented, insulation failure, disconnection, and the like can be prevented, and reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a connection diagram showing a winding structure for a brushless motor according to the present invention.

[Explanation of symbols]

N Middle point 10, 11, 12 Stator winding (U, V, W phase winding) 10a, 11a, 12a One end 10b, 11b, 12b Inner winding 10c, 11c, 12c Outer winding 10d, 11d, 12d Other end U1, V1, W1 Intermediate terminal φD1, φD2 Wire diameter

Claims (2)

[Claims] A multi-phase stator winding having one end (10a, 11a, 12a) connected to a middle point (N) and the other end (10d, 11d, 12d).
(10, 11, 12), an intermediate terminal (U1, V1, W1) is provided at an intermediate position of each of the stator windings (10, 11, 12), and the intermediate point (N) and each intermediate terminal (U1 , V1, W1) and the outer windings (10c, 11c, 12c) between the intermediate terminals (U1, V1, W1) and the other ends (10d, 11d, 12d). In the winding structure for a brushless motor in which electrification for the inner winding can be selected,
(10b, 11b, 12b) and the outer winding (10c, 11c, 12c) wire diameter (φD1, φ
D2) is different from each other, a winding structure for a brushless motor. 2. A wire diameter (φD) of the inner windings (10b, 11b, 12b).
The winding structure for a brushless motor according to claim 1, wherein 1) is larger than a wire diameter (φD2) of the outer windings (10c, 11c, 12c).