JPH04183245A - Motor provided with speed detector - Google Patents

Abstract

PURPOSE:To reduce manpower and cost and to obtain a motor, in which insufficient adhesion is eliminated, by providing a sensor magnet and a resin molded boss, respectively, with mutually fittable recesses and protrusions and after fitting then mutually, press fitting the boss to a rotary shaft thereby securing the sensor magnet to the rotary shaft. CONSTITUTION:Protrusions 11 are provided on one end face of a boss 12 whereas recesses 10 are made in the end face of a sensor magnet 7 abutting on the end face of the boss 12. Inner diameter of the sensor magnet 7 is set slightly larger than the outer diameter of a rotary shaft 8 so that the sensor magnet 7 is not adversely effected. Inner diameter of the resin molded boss 12 is set to provide a tightening margin for the shaft 8. The recesses 10 in the sensor magnet 7 are fit to the protrusions 11 of the boss 12 and then the sensor magnet 7 and the boss 12 are press fit to the rotary shaft 8 thus securing the sensor magnet 7 to the rotary shaft 8. Since no adhesion process is required, cleaning process and the like can be eliminated resulting in elimination of insufficient securing of sensor magnet such as insufficient adhesion.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for fixing a sensor magnet that provides a rotation signal to a speed detector in an electric motor equipped with a speed detector.

2. Description of the Related Art In recent years, with the development of variable capacity technology for compressors and the like in the air conditioning field, there has been an increasing demand for controlling the rotational speed of fan motors for indoor ventilation.

In general, induction motors are used for indoor ventilation fan motors, and phase control is performed using thyristors to vary the rotation speed. It is detected and controlled by a detector.

Next, a conventional technique will be explained with reference to FIG.

FIG. 4 is a sectional view of a conventional induction motor with a speed detector, in which a stator core 1, windings 2, and molded resin 3 form a stator. 4 is a printed circuit board, 5 is a printed circuit board 4
6 is a rotor press-fitted and fixed to the rotating shaft 8, and 7 is a sensor magnet mounted to face the speed detector 5. Reference numeral 9 denotes a bearing that rotatably supports the rotating shaft 8.

The sensor magnet 7 is adhesively fixed to the rotor 6 so as to face the speed detector 5.

Problems that the invention aims to solve However, the rotor cannot be fixed with adhesive as described above.

Each part must be cleaned to remove oil and other substances adhering to the shaft that adversely affect adhesion. Furthermore, in an electric motor such as an induction motor, a rotor having a secondary winding generates heat, so the adhesive must also be heat resistant, and care must be taken when handling it. Therefore, there is a drawback that it requires a lot of man-hours and costs are high.

The present invention solves the above-mentioned problems, and provides an electric motor that reduces the number of working steps, reduces costs, and eliminates bonding defects.

Means for Solving the Problems In order to solve these conventional problems, the present invention provides a sensor magnet and a boss of a resin molded product with a convex portion and a concave portion that fit into each other. The sensor magnet is fixed to the rotating shaft by press-fitting the boss into the rotating shaft.

Effect: With the above configuration, the sensor magnet can be easily fixed to the rotating shaft by the boss, and the bonding process can be eliminated, thereby reducing the number of work steps.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. It should be noted that the present invention relates to fixing a sensor magnet, and other parts are the same as those of the conventional one, are given the same numbers, and descriptions thereof will be omitted.

FIG. 1 is a sectional view of an electric motor with a speed detector according to an embodiment of the present invention. FIG. 2 is a perspective view of the sensor magnet 7, and FIG. 3 is a perspective view of the boss 12, which is a resin molded product. One end surface of the boss 12 has a convex portion 11, and the end surface of the sensor magnet 7 that abuts this end surface has a convex portion 11. A recess 10 is provided in each case. The inner diameter of the sensor magnet 7 is made slightly larger than the outer diameter of the rotating shaft 8 so as not to adversely affect the sensor magnet 7. The inner diameter of the boss 12, which is a resin molded product, is set to such a size that it has a tightening margin with respect to the shaft 8. The recess 10 and boss 1 of this sensor magnet 7
The sensor magnet 7 is fixed to the rotating shaft 8 by fitting the two protrusions 11 into each other and press-fitting and fixing them to the rotating shaft 8.

In the present invention, the sensor magnet is provided with a concave portion and the boss is provided with a convex portion, but it goes without saying that conversely, the sensor magnet may be provided with a convex portion, and the boss may be provided with a concave portion.

Effects of the Invention As is clear from the above explanation, according to the present invention, processes such as cleaning can be eliminated by eliminating the adhesion process, the assembly process can be simplified and streamlined, and sensor magnet fixing failures such as poor adhesion can be avoided. (Quality can be improved.

[Brief explanation of the drawing]

FIG. 1 is a half-sectional view of an electric motor with a speed detector according to an embodiment of the present invention, and FIG. 2 is a perspective view of the same sensor magnet.
FIG. 3 is a perspective view of the boss, and FIG. 4 is a half-sectional view of a conventional electric motor with a speed detector. 1... Stator core, 4... Printed circuit board, 5... Speed detector, 7... Sensor magnet, 10... Sensor Concave portion of magnet 7, 11...Convex portion of boss 12, 12...
·boss. Figure 1 1-11 Enbo Snake + Stock Heart 7---Dengederipahyu Soto Figure 2 Figure 4

Claims (1)

[Claims] In an electric motor that includes a speed detector on the stator side and consists of a rotor and a rotating shaft, a resin-molded boss and a sensor magnet that sends a signal to the speed detector are provided with convex portions and concave portions that fit into each other. An electric motor with a speed detector, which is formed by press-fitting and fixing the matched boss onto the rotating shaft.