JPH1127912A - Method for manufacturing electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of an air gap by accommodating a rotor into a stator cylindrical space by tight insertion or press fit, fixing a bearing for supporting a rotor output shaft to a stator, and then setting the outer diameter of the rotor to a specific dimension that is slightly smaller than the diameter of the stator cylindrical space. SOLUTION: When a rotor is inserted into a stator, the outer diameter of a rotor 2 has a slight clamping margin for the inner diameter of a stator 1. Specifically, when the rotor 2 is to be inserted into the stator 1, a protrusion 5 where a clamping margin is added to an air gap is provided at the inner diameter of the stator 1 or the outer diameter of the rotor, press fit is conducted by utilizing the protrusion 5, and burning is made for example, by a laser after an electric motor is completed. Also, the temperature of the rotor 2 is maintained at a high value for the stator 1 and press fit is made by utilizing the difference in thermal expansion, and a prescribed air gap is achieved when the rotor is cooled and the temperature becomes identical to that of the stator due to shrinkage after the electric motor is completed. The air gap can be set to a small value, thus achieving an highly efficient electric motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a motor used as a drive source for various home appliances.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view of a conventional motor. 1
Is a stator formed by resin molding, 2 is a rotor, 3 is a bracket having a bearing holding portion, and 4 is an air gap between the stator and the rotor. Since individual components vary with respect to the target dimensions and accuracy in design, there is considerable eccentricity in the air gap of the completed motor in these combinations.

[0003]

Generally, in an electric motor, when an eccentricity exists in an air gap, magnetic non-parallelism occurs, so that a magnetic attraction force is generated and causes noise. Conventionally, in order to suppress this eccentricity as much as possible, high accuracy is required for individual parts such as the stator core inner diameter, bracket spigot part (stator side), bracket spigot part (bracket side), and rotor outer diameter runout. In addition, there is a limit due to the requirement for assembly accuracy in which these are combined, and this has been a major factor in determining the set value of the air gap of the motor.

It is an object of the present invention to improve the accuracy of the stator and the rotor, that is, the accuracy of the air gap, and to maintain the accuracy of the air gap even after the completion of the motor. And

[0005]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention provides a rotor having a substantially cylindrical shape, which penetrates the center in the axial direction, and whose output shaft is supported and fixed, and which houses the rotor therein. A stator having a substantially cylindrical space, and a bearing rotatably supporting the rotor with respect to the stator, wherein the maximum outer diameter of the rotor is equal to or slightly smaller than the minimum diameter of the stator cylindrical space. A first step of accommodating the rotor in the stator cylindrical space by closely inserting or press-fitting, and thereafter, a bearing for supporting the rotor output shaft. 2nd fixed to stator
And a third step of reducing the rotor outer diameter to a predetermined size slightly smaller than the diameter of the stator cylindrical space.

As a result, the accuracy of the stator and the rotor, that is, the accuracy of the air gap is improved, and the state of the accuracy of the air gap can be maintained even after the completion of the motor.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to the first, second and third aspects of the present invention is to insert a rotor into a stator formed by forming a frame with a core made of a resin, a steel plate, or the like. However, in the electric motor combining the brackets holding the bearings, a slight interference is provided when inserting the rotor into the stator, and lightly press-fitted to assemble the stator. , That is, the accuracy of the air gap can be improved.

According to a fourth aspect of the present invention, the stator and the rotor assembled by press fitting according to the first, second, and third aspects are assembled without positioning the bracket in the radial direction. Yes, this allows the air gap to remain accurate even after the motor is completed.

[0009]

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

(Embodiment 1) FIG. 1 shows a state in which a rotor is press-fitted into a stator of an electric motor in the present invention, wherein 1 is a stator, and 2 is a rotor. Is inserted into the stator, the outer diameter of the rotor 2 has a slight interference with the inner diameter of the stator 1. FIG. 2 shows an example of how to give the interference at this time. FIG. 2A shows that when the rotor 2 is inserted into the stator 1, a protrusion 5 is added to the inner diameter of the stator 1 or the outer diameter of the rotor 2 by adding an interference to the air gap, and the protrusion 5 is used. The protrusions 5 are burnt off with a laser or the like after completion of the motor. FIG. 2B shows that when the rotor 2 is inserted into the stator 1, the temperature of the rotor 2 is maintained at a high temperature, and the stator 2 is press-fitted by utilizing a difference in thermal expansion. 2 has a specified air gap when it is cooled and contracted to reach the same temperature as the stator.

(Embodiment 2) FIG. 3 shows a state in which a completed rotor 2 is press-fitted into a completed stator 1 of an electric motor, and then the bracket 3 is assembled without any positioning in the radial direction. Thereby, the assembly is performed according to the bearing 6 which does not require the accuracy of the spigot portion and has high accuracy. With respect to the method of fixing the bracket 3, conventional rivets, bolts, adhesives, and the like may be used, provided that the accuracy is not changed after fixing.

[0012]

According to the first and second aspects of the present invention, the accuracy of the stator and the rotor, that is, the accuracy of the air gap is improved, and the accuracy of the air gap can be maintained even after the completion of the motor. Become like That is, if the same air gap is maintained, a low-noise motor can be realized, and the air gap can be set small, so that a high-efficiency motor can be realized.

According to the third aspect of the present invention, the accuracy of the air gap can be improved without requiring large-scale equipment such as a laser device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state in which a completed rotor is press-fitted into a completed stator according to an embodiment of the present invention.

FIG. 2A shows a method of press-fitting a completed rotor to a completed stator. FIG. 2B shows a method of press-fitting a completed rotor to a completed stator.

FIG. 3 is a diagram showing a state in which a bracket is assembled without any positioning in a radial direction after press-fitting a completed rotor into a completed stator.

FIG. 4 is a sectional view of a conventional electric motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator 2 Rotor 3 Bracket 4 Air gap 5 Projection 6 Bearing

Claims (4)

[Claims] A rotor having a substantially cylindrical shape, an output shaft being supported and fixed through the center in the axial direction, a stator having a substantially cylindrical space for accommodating the rotor therein, and the rotor comprising: A method for manufacturing a motor, comprising: a bearing rotatably supported by a stator, wherein the rotor maximum outer diameter is configured to be equal to or slightly larger than the minimum diameter of the stator cylindrical space. A first step of accommodating the rotor in the stator cylindrical space by close insertion or press-fitting, and then a second step of fixing the bearing supporting the rotor output shaft to the stator.
And a third step of reducing the rotor outer diameter to a predetermined dimension slightly smaller than the diameter of the stator cylindrical space. 2. A rotor having a substantially cylindrical shape, an output shaft being supported and fixed through the center in the axial direction, a stator having a substantially cylindrical space for accommodating the rotor therein, and the rotor comprising: A bearing rotatably supported by a stator, wherein a plurality of protrusions are provided on an outer peripheral surface of the rotor or on a surface of the stator facing the rotor, so that the maximum outer diameter of the rotor can be reduced by the stator. A method for manufacturing an electric motor configured to be equal to or slightly larger than a minimum diameter of a cylindrical space, comprising: a first step of closely inserting or press-fitting a rotor into a stator cylindrical space; A second step of fixing the bearing that supports the rotor output shaft to the stator, and then removing the protrusion to make the rotor outer diameter slightly smaller than the diameter of the stator cylindrical space. 3rd dimension
A method for manufacturing an electric motor, comprising the steps of: 3. A rotor having a substantially cylindrical shape, an output shaft being supported and fixed through the center in the axial direction, a stator having a substantially cylindrical space for accommodating the rotor therein, and the rotor comprising: A stator rotatably supported by the stator, and configured so that the maximum outer diameter is equal to or slightly larger than the minimum diameter of the stator cylindrical space by keeping the rotor at a high temperature. A method for manufacturing an electric motor, comprising: a first step of closely inserting or press-fitting a rotor in a stator cylindrical space while keeping the rotor in a high temperature state; and thereafter, fixing a bearing for supporting the rotor output shaft. 2nd fixed to child
And a third step of thermally shrinking the rotor by shifting the rotor to a normal temperature state to reduce the outer diameter to a predetermined size slightly smaller than the diameter of the stator cylindrical space. A method for manufacturing a motor. 4. A bracket is not mounted on the stator and the rotor assembled by the method for manufacturing an electric motor according to claim 1, 2 or 3, but is freely assembled without radial positioning of the bracket. Manufacturing method of an electric motor.