JPH0733579Y2 - Induction motor speed detection element mounting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an improvement of a device for mounting a speed detection element for detecting the rotation speed of an induction motor.

[Conventional technology]

BACKGROUND ART Conventionally, in an electric motor used for a so-called blower or the like, which sends out warm air and cold air in a heating / cooling device, the air volume can be automatically adjusted according to a room temperature or the like by continuously changing the speed of the electric motor in order to improve its use efficiency. It is like this.

In order to continuously change the speed of the electric motor, generally, the magnetism (N pole, S pole) of a permanent magnet attached to the rotor shaft of the electric motor is rotated by a rotation speed detecting element such as a Hall element. A pulse signal proportional to the speed is detected, the pulse signal is sent to the switching unit as a speed feedback signal, and the switching unit controls the on / off timing by the feedback signal to control the rotation speed of the electric motor. There is.

An induction motor (hereinafter, simply referred to as an electric motor) to which the speed detecting element such as the hall element is attached is, for example, a seventh motor.
Some are shown in the figure.

In the figure, 1 is a stator core, 2 is a coil wound around the stator core 1, and the stator core 1 is held by a pair of bowl-shaped cases 3 and 3a press-fitted from both sides in the axial direction. Reference numeral 4 denotes a rotor inserted in the rotor insertion hole of the stator core 1, which is fixed to the rotor shaft 5 and which has a bearing housing 6 and a bearing recessed in the center of the bottom surface of the case 3. The rotor 4 is rotatably held in the rotor insertion hole of the stator core 1 by being supported by the bearing casings 6 and 6a through the rotor casings 6 and 6a. 8 is one case
A circle fixed to the upper outer circumference of the magnet mounting disk 9 mounted on the protruding end of the rotor shaft 5 protruding outward from the bearing housing 6a of 3a (leftward in FIG. 7) by, for example, resin molding. A plate-shaped permanent magnet, 10 is a rotation speed detecting element composed of a Hall element or the like provided at a peripheral edge of the permanent magnet 8 at a predetermined interval, and this speed detecting element 10 is, as shown in FIG. And case
The speed detecting element is fitted and held by the board mounting body 11 mounted across the bottom surface of 3a so as to face the peripheral surface of the permanent magnet 8.
The lead of 10 is electrically connected to the conductive portion of the printed circuit board 13 fixed to the back surface of the board mounting body 11 through the insertion hole 12 of the board mounting body 11. Reference numeral 14 denotes a cover body which is attached to the bottom surface of the case 3a from the outside so as to prevent the permanent magnet 8 and the speed detecting element 10 from being exposed to the outside.

[Problems to be solved by the device]

In the induction motor configured with the speed detection element 10 as described above, the speed (rotation speed) detection element 10 of the rotor 4 is detected.
Because the permanent magnet 8 is attached to the tip of the rotor shaft 5 protruding outward from the bearing housing 6a (this is because the bottom surface of the case 3,3a is bent in a U shape on the outer circumference of the bearing housing 6,6a). The case 3,3a is made stronger because the strength of the case 3,3a is increased.
There is no space to install the permanent magnet 8 inside), and it is unavoidable to place it outside the case 3a. However, in recent years, air-conditioning equipment and indoor ventilation equipment have been designed to be as compact and lightweight as possible due to the location and space of the installation, and electric motors such as blowers attached to these equipment must be compact and flat. To be done. Therefore, as described above, when the speed detecting element (including the permanent magnet 8) 10 is installed outside the case 3a, the dimension of the electric motor in the axial direction becomes long, and the size and flattening of the electric motor are prevented. It was a factor. or,
Providing the speed detecting element or the like outside the case 3a requires the cover body 14 to cover the case 3a, and also requires a work process for attaching the cover body 14 and so on. However, there is a problem that it takes time and labor, and the number of parts increases, resulting in high cost.

In view of the above problems, the present invention provides a speed detecting element mounting device for a motor, which enables a small and flat motor by effectively utilizing a narrow space inside the motor and mounting the speed detecting element with a simple structure. The purpose is to provide.

[Means for Solving the Problems]

In the present invention, the peripheral wall of the bearing housing of the case that houses the stator core is press-formed into a double wall shape to provide a flat bottom surface of the case,
A speed detecting element is arranged in a space between the peripheral wall of the double-walled bearing housing and the end portion of the coil wound around the stator core, and the end ring is provided on the rotor side. The bottom cylindrical permanent magnet is configured such that its cylindrical wall portion is attached so as to correspond to the speed detecting element.

[Action]

The present invention effectively utilizes a narrow space in an electric motor to incorporate a speed detecting element and a permanent magnet, and the speed detecting element and the permanent magnet can prevent the speed detecting element from being blocked by another object in a narrow space. In addition to performing reliable detection by arranging them facing each other, by installing the speed detection element etc. in the case, the axial dimension of the motor can be shortened and the parts used can be reduced to make the motor compact and flat. , Characterized by enabling economical production.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In FIGS. 1 and 2, the same reference numerals as those in FIG. 7 indicate the same parts.

In FIG. 1, a stator core 1 wound with a coil 2 constituting an electric motor and a stator core 1 fixed to a rotor shaft 5 are shown.
The pair of cases 3 and 3a for accommodating the rotor 4 which is rotatably inserted into the rotor insertion hole are the bearing casings 21 and 21a for accommodating the bearing 7 in the center of the bottom surface thereof, and the outer peripheral portion is thick. As described above, press molding is performed into a double wall shape, and a space S is provided between the double wall portion a and the coil end portion 2a of the coil 2 for installing the speed detecting element 10 such as a Hall element. When the speed detecting element 10 is attached to the empty space S, as shown in FIG.
As shown in FIG. 2, the printed circuit board 13 on which the speed detecting element 10 is attached toward the 4a side is screwed to the flat bottom surface of the case 3a through a thick insulating member 22 to detect the speed. Mount the element 10 in the space S.

On the other hand, on the side of the end ring 4a of the rotor 4 facing the magnetic detection portion of the speed detecting element 10, as shown in FIG. Of the permanent magnet 23, the other flat surface having no protruding portion is directed toward the speed detecting element side, and the rotor shaft 5 is loosely fitted to the center portion thereof and abuts on the end ring 4a. The permanent magnet 23 is fixed to the rotor 4 by inserting the provided boss portion 4b into the thick protruding portion of the permanent magnet 23 and crushing the protruding end thereof.

As described above, the outer peripheries of the bearing housings 21 and 21a of the cases 3 and 3a are formed in a double wall shape, and the outer peripheral surfaces of the double-walled portions a and the coil end portions 2a and the case 3 are formed. Between the flat bottom surface of the rotor 3 and the end ring 4a of the rotor 4
10. A space S for mounting is formed, and by effectively utilizing this space S, the speed detecting element 10 is mounted on the case 3a side, and the permanent magnet 23 is mounted on the end ring 4a side of the rotor 4 so as to be arranged close to each other. By doing so, the speed detecting element mounting device of the present invention is configured.

Next, FIG. 3 shows a second embodiment of the device of the present invention. This embodiment uses the structure of the electric motor, that is, the space S of the case 3a described in the first embodiment to detect the speed detecting element. Although the points 10 are the same, the mounting structure of the speed detecting element 10 is different, and the mounting structure of the speed detecting element 10 will be described below with reference to FIGS. 4 to 6 including FIG. This second
In the embodiment, the magnetic detection part of the speed detection element 10 is first
Instead of facing the rotor 4 side as in the embodiment, as shown in FIG. 3, it is mounted toward the coil end portion 2a side.

In FIG. 6, reference numeral 25 is a mounting frame body of the printed circuit board 13 on which the speed detecting element 10 is horizontally mounted, which is molded into a U-shape with synthetic resin, and the printed circuit board 13 is formed as shown in FIG. The mounting pieces 26 on both sides of the mounting frame 25 are attached to the locking step portions 27 provided at the center inside the mounting pieces 26, 26 so as not to fall off. Next, the speed detecting element 10 is attached to the bridging portion 28 of the mounting frame 25 as shown in FIG.
The base portion is horizontally inserted into the fitting portion b formed in the upper portion, and the lead is penetrated through the hole portion c formed in the fitting portion b to form a printed circuit board.
By connecting the speed detecting element 10 to the mounting frame 25
The magnetic detector is attached to the bottom of the box. After mounting the speed detecting element 10 as described above, the mounting frame 25
As shown in FIG. 5, the mounting portions 26 of the mounting pieces 26, 26 protruding from the mounting holes e projecting from the mounting hole e formed in the case 3a,
By heating and crushing the protruding end, the mounting frame 25 is supported by the case 3a as shown in FIGS. 3 and 4,
Install it in the space S inside the case 3a.

On the other hand, as shown in FIG. 3, the end ring 4a of the rotor 4 has a permanent magnet 23 formed in a cylindrical shape with a bottom, and the cylindrical wall portion f on the outer periphery thereof is located between the coil 2 and the bearing housing 21a. Install as you would. As a result, the speed detection element mounted on the mounting frame 25
The magnetism detecting unit 10 can be arranged in proximity to the inside of the outer peripheral portion of the permanent magnet 23 so as to face it.

In FIGS. 2 and 4, reference numeral 29 is a lead wire for connecting the speed detecting element 10 and a phase control circuit (not shown).
Further, 30 is an insulator attached inside the bottom surface of the case 3a in the mounting frame 25, and insulates between the conductive portion of the printed board 13 and the bottom surface of the case 3a.

The present invention is configured as described above, and when the rotor 4 is rotated by energizing the electric motor, the permanent magnet 23 attached to the end ring 4a located on the case 3a side of the rotor 4 and the case 3a side are attached. Since the speed detecting element 10 provided in the space S between the bearing housing 21a and the end portion 2a of the coil 2 is disposed close to each other on the bottom surface of the case 3a through the insulating mounting member, the rotor 4 A value proportional to the rotation speed of the can be reliably detected by the speed detecting element 10 through the corresponding permanent magnet 23. Based on this detected value, the phase control circuit outputs an electric signal proportional to the speed and the switching unit is turned on. The rotation speed of the rotor 4 can be arbitrarily controlled by appropriately shifting the timing of off control.

[Effect of device]

Since the present invention is configured as described above, it has the following effects.

The present invention is directed to a narrow space formed between an outer circumference of a bearing housing into which a bearing for rotatably supporting a rotor shaft inside a case for housing and fixing a stator core is fitted, and a coil wound around the stator core. In the empty space, a U-shaped mounting frame that is joined to the printed circuit board and has a speed detecting element that projects horizontally toward the rotor is mounted, while on the rotor side, the mounting frame is attached to its end ring. The permanent magnet formed in a cylindrical shape with a bottom corresponding to the body,
Since the mounting device of the speed detecting element is configured by mounting the outer peripheral cylindrical wall portion between the speed detecting element and the coil, and by mounting the cylinder wall portion close to the speed detecting element side, Since the speed detecting element can be attached to the coil wound around the stator winding while being magnetically shielded by the cylindrical wall portion of the permanent magnet, the speed detecting element is generated from the coil during operation of the induction motor. It is hardly affected by the rotating magnetic field. Therefore, the speed detecting element can be surely avoided from the adverse effect of the rotating magnetic field. That is, the speed detecting element can favorably avoid the influence of the rotating magnetic field by the cylindrical wall portion on the outer circumference of the permanent magnet, and as a result, the rotational speed can be accurately detected without causing a malfunction.

Further, according to the present invention, since the bearing housing in which the bearing is fitted is formed with a double wall structure, a bent portion for increasing the mechanical strength of the bottom surface of the case is not required as in the conventional case. It becomes easy to provide a narrow space in the space, and as a result, the space can be used to quickly and easily mount the mounting frame body equipped with the speed detection element to the bottom surface of the case, and the permanent magnet is used. By forming the bottomed cylindrical shape, the speed detecting element protruding horizontally from the mounting frame is isolated from the coil,
In addition, the use of a bottomed cylindrical permanent magnet allows installation toward the rotor side, and as a result, a bottomed cylindrical permanent magnet is attached to the rotor end ring, which enables speed detection. The element and the permanent magnet can be arranged close to each other by effectively utilizing the space in the electric motor, and thereby the axial dimension of the electric motor can be shortened as much as possible. Moreover, as compared with the conventional configuration in which the speed detection element is mounted on the outside of the electric motor, the narrow space inside the electric motor can be effectively used, so that the electric motor can be made compact, lightweight, and covered. As the number of unnecessary parts such as the body and the permanent magnet mounting plate is reduced, the assembling process can be shortened, and the reduction of the number of parts makes it possible to economically manufacture the induction motor.

Further, the speed detecting element is attached to the bottom of the case in an arbitrary direction corresponding to the bottomed cylindrical permanent magnet attached to the end ring of the rotor through the insulating attachment member in the space inside the case. In addition, at the time of assembling the electric motor, the speed detecting element is attached to the bottom surface of the case, and the end ring portion of the rotor side has a permanent magnet formed in a cylindrical shape with a bottom. The motor can be smoothly and satisfactorily assembled by inserting the rotor into the stator core, and the speed detection element can be placed close to the permanent magnet. Therefore, the rotation speed of the electric motor can be accurately detected.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an electric motor showing a mounting state of the device of the present invention, FIG. 2 is an enlarged sectional view of an essential part of FIG. 1, and FIG. 3 is a vertical sectional view of an electric motor showing another embodiment of the device of the present invention. Fig. 4 is an enlarged vertical sectional view of an essential part of Fig. 3, Fig. 5 is a cross-sectional plan view of an essential part of Fig. 4, Fig. 6 is a perspective view of the same as above, and Fig. 7 shows a mounting state of a conventional device. It is a longitudinal cross-sectional view of the electric motor shown. 1 ... Stator core, 2 ... Coil 2a ... Coil end part, 3,3a ... Case 4 ... Rotor, 4a ... End ring S ... Vacancy, a ... Double wall part 10 ... … Speed detection element, 13… Printed circuit board 21a… Bearing housing, 23… Permanent magnet

Claims (1)

[Scope of utility model registration request] 1. A bearing casing 21a, into which a bearing 7 for rotatably supporting a rotor shaft 5 is fitted, is provided on the bottom surface of a case 3a for accommodating and fixing a stator core 1, and the outer peripheral portion of the bearing casing 21a is further provided. The case 3a is formed in a double wall shape and the bottom surface of the case 3a is provided in a flat shape. The outer circumference of the bearing housing 21a inside the flat bottom surface of the case 3a and the coil end portion 2a of the coil 2 wound around the stator core 1 are formed. A narrow space S is formed between the mounting space 25 and a mounting frame 25 formed in a U shape with a built-in printed circuit board 13 attached to the space S. The speed detecting element 10 connected to the printed circuit board 13 is horizontally projected toward the end ring 4a side of the rotor 4 rotatably inserted in the stator core 1, and is attached to the end ring 4a of the rotor 4. Is a permanent magnet 23 formed in a cylindrical shape with a bottom, and a cylinder wall portion f on the outer periphery of the permanent magnet 23 is a coil of the speed detecting element 10 and the coil. In a state interposed between the command portion 2a, and a speed detecting device mounting apparatus for an induction motor is characterized in that to attach in close proximity to said velocity detecting element 10.