JP2518183Y2 - Motor speed detection element mounting device - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a mounting structure of a rotation speed detecting element for detecting the rotation speed of an electric motor.

[0002]

2. Description of the Related Art Conventionally, for example, in an oil fan heater and various cooling and heating equipment, an electric motor used as a blower for sending hot air or cold air has no need for controlling the rotation speed of the electric motor in order to improve the air blowing efficiency. It is provided so that the amount of air blown can be automatically adjusted according to the room temperature or the like by shifting the gears.

When varying the rotation speed of the electric motor,
When a permanent magnet is not used in the rotor of the electric motor, a rotor plate made of a permanent magnet is fixed to the rotor shaft of the rotor, and the magnetic field of the rotating permanent magnet (N pole / S
Pole) is detected as a pulse signal proportional to the rotation speed of the rotor, for example, by a rotation speed detection element such as a Hall element, and this pulse signal is used as a speed feedback signal in the switching unit composed of transistors of the speed control unit. It outputs and turns on this switching unit according to the feedback signal.
The rotation speed of the electric motor was controlled by controlling the timing of turning off.

As an electric motor to which the above-mentioned rotational speed detecting element is attached, for example, the one shown in FIG. 8 has been proposed, and its structure will be described with reference to FIG. A wound bobbin 2 is attached, and a rotor insertion hole 3 is provided in the lower portion, and a rotor 4 is rotatably inserted therein. Numerals 5 and 6 are brackets containing a bearing 8 that rotatably supports the rotor shaft 7 of the rotor 4, and the rotor shaft 7 is a bearing when the rotor 4 is inserted into the insertion hole 3 of the stator core 1. 8 to contact the front and rear surfaces of the stator core 1, and in this state, the brackets 5 and 6 are fastened to the stator core 1 by using tightening screws, whereby the rotor 4
Is rotatably supported in the insertion hole 3. 9 is the rear side (Fig. 8
(In the left direction), the disk-shaped permanent magnet 10 fixed to the end ring 4a of the rotor 4 is opposed to the peripheral edge of the disk-shaped permanent magnet 9 at a predetermined interval. The rotation speed detecting element is a hall element or the like provided inside the bracket 6. Then, as shown in FIG. 8, the rotation speed detecting element 10 has a disk-like shape on the printed circuit board 12 mounted on the inner peripheral edge of the bracket 6 on the rear side via an insulating mounting member 11 by a screw member. Permanent magnet 9
It is located close to and facing. 13 is a printed circuit board 1
The rotation speed detecting element 10 and a control circuit (not shown) are connected to each other by a lead wire attached to No. 2.

[0005]

As described above, in the motor equipped with the rotation speed detecting element, when the rotor itself is not formed by the permanent magnet, that is, as described above, the end ring of the rotor is used. In the case of a structure in which a permanent magnet is attached to the rotating speed detecting element, the rotating speed detecting element prevents the malfunction due to the adverse effect of the rotating magnetic field generated from the rotor or the stator core during the operation of the electric motor. It was necessary to install it as far away from the rotor as possible. However, for example, in indoor equipment such as air-conditioning equipment, there is an urgent need for downsizing and weight reduction in terms of installation location, installation space, etc., and a blower electric motor is no exception. Therefore, in order to avoid the mounting position of the rotation speed detecting element from the influence of the rotating magnetic field generated by the operation of the electric motor,
Providing it at a location distant from the rotor inevitably requires lengthening the length of the electric motor in the axial direction, which causes a problem of increasing the size of the electric motor.

When the rotation speed detecting element needs to be replaced due to a failure or the like, the pair of brackets and the stator core are unfixed each time, and the printed circuit board having the rotation speed detecting element is removed. Since this has to be removed from the inner peripheral edge of the built-in bracket and replaced, there is a problem that the replacement work takes a lot of time and effort. Moreover, the printed circuit board provided with the rotation speed detecting element is fixed to the inner peripheral edge of the bracket 6 by using the plurality of screw members via the mounting member 11, so that the assembly work of the electric motor is very troublesome. It was

Further, the disk-shaped permanent magnet fixed to the end ring of the rotor must be large in diameter according to the diameter of the end ring, which is uneconomical. Since the end ring itself is usually manufactured by aluminum die cast, if the part to which the disk-shaped permanent magnet is attached is not flat but inclined or has irregularities, it will be permanently attached to this part. When the magnet is attached, it is difficult for the permanent magnet to accurately correspond to the rotation speed detection element, and there is a problem that the speed of the rotor cannot be accurately detected.

In view of the above-mentioned various problems, the present invention effectively utilizes a narrow space in a bracket that rotatably supports a rotor shaft of an electric motor, and arranges a permanent magnet in the space. An object of the present invention is to provide a mounting device for a rotation speed detecting element, which has a simple structure and can be easily replaced by mounting the rotation speed detecting element corresponding to the permanent magnet from the outside in one operation.

[0009]

DISCLOSURE OF THE INVENTION According to the present invention, among a pair of brackets for rotatably supporting a rotor shaft of a rotor at both ends thereof, a bearing rear portion of a bracket for preventing the rotor shaft from protruding to the outside of an electric motor. A small-diameter plate-shaped permanent magnet for detecting the rotational speed was attached to the end of the rotor shaft protruding from the bearing in the internal space formed on the side, and this permanent magnet was attached to the end of the rotor shaft and stored. Fit a printed circuit board with a rotation speed detecting element composed of a Hall element or the like also serving as a lid for the opening in the opening above the space of the bracket, with the speed detecting element corresponding to the permanent magnet. Since the mounting device of the rotation speed detecting element is configured by mounting the rotating speed detecting element in almost one operation according to the fitting method or the like, its operation is as follows.

[0010]

According to the present invention, a disk-shaped permanent magnet having a small diameter is attached to the end of the rotor shaft in a space in a bracket having an open end at the upper part, and an opening in the space corresponding to the outer peripheral edge of this permanent magnet is formed. Since the printed circuit board on which the rotation speed detecting element is attached at a position corresponding to the permanent magnet is attached to the portion, the disk-shaped permanent magnet has a space provided outside the bearing of the bracket. By using the rotor, it is possible to mount the rotor at a distance that is not significantly affected by the rotating magnetic field. Therefore, the rotation speed of the rotor can be accurately detected without causing a malfunction. . Also, since the permanent magnet itself can be mounted by effectively utilizing the space behind the bracket, the motor can be mounted in the axial direction of the rotor as compared with the conventional structure in which the permanent magnet is mounted on the end ring of the rotor. Since the distance between the end portion and the bearing can be made as narrow as possible, the size of the electric motor can be reduced.

Further, since the opening at the upper part of the empty space of the bracket can be closed by attaching a printed circuit board provided with the rotation speed detecting element without specially providing a lid, the opening of the rotation speed detecting element The mounting structure can be simply configured because the printed circuit board can also serve as the lid as it is. Moreover, since the printed circuit board can be attached in almost one operation by adopting the fitting method, the assembling work of the electric motor can be performed quickly and easily.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1 and FIG. 2, 20 is a cornering coil type induction electric machine (hereinafter, referred to as an electric motor) in which the device of the present invention is implemented, 21 is a stator core of the electric motor 20, and a coil bobbin 22a having a coil 22 wound on the upper portion thereof. Is attached via an iron core 23 for a yoke, which is fitted to the iron core 21, and has a rotor insertion hole 24 in the lower portion, and
A pair of chamfering coils 25 are wound around the stator core 21 so as not to project into the rotor insertion hole 24 at a position on the diagonal line of the periphery of the insertion hole 24. Two
Reference numeral 6 denotes a rotor rotatably inserted and held in the rotor insertion hole 24, and 27 denotes a rotor shaft press-fitted and attached to the rotor 26. Reference numerals 28 and 29 denote front and rear brackets attached to the stator core 21 at the front and rear sides of the rotor insertion hole 24, respectively.
As shown in FIG. 2, bearing support cylinders c and d, into which the bearings a and b such as ball bearings are inserted and held, are integrally formed at the center of the bulge.

The brackets 28 and 29 are inserted into the rotor insertion holes 24 of the stator core 21 and the rotor 26.
Is inserted into the rotor shaft 27 via bearings a and b, respectively, and abuts against the end surface of the stator core 21, and then the brackets 28 and 29 are attached to the stator core 21 at their longitudinal ends. The rotor 26 is rotatably held in the rotor insertion hole 24 by tightening with the tightening bolts 30 in a state where the rotor 26 is clamped. Next, the bracket 2
8 and 29, the bearing support cylinder c of the front bracket 28 is formed with an insertion hole 28a for allowing the rotor shaft 27 penetrating the bearing a to project outward, and the bearing of the rear bracket 29. As shown in FIG. 2, a narrow box-shaped accommodating portion f for accommodating the terminal portion e of the rotor shaft 27 protruding from the bearing b is integrally formed in the rear portion of the support cylinder d.
An opening h for communicating with the outside is formed in an upper part of the space g in the accommodation part f. A disk-shaped permanent magnet 31 is attached to a terminal portion e of the rotor shaft 27 protruding into the housing portion f at a position corresponding to the opening h. Needless to say, the accommodating portion f can be formed integrally with the bearing support cylinder d when the bracket 29 is molded by an aluminum die cast.

In FIG. 2, reference numeral 32 denotes a printed circuit board which also serves as a lid for closing the opening h of the bracket 29, and which corresponds to the outer peripheral edge of the permanent magnet 31 fixed to the end e of the rotor shaft 27 on the back surface thereof. At the position, components such as a rotation speed detecting element 33 including a Hall IC and a capacitor (not shown) for surge protection are mounted. As shown in FIG. 4, a bracket 29 is attached to one end of the printed circuit board 32.
Is formed with a through hole 36 of a screw 35 which is screwed into a screw hole 34 screwed in a flat portion of the end edge of the opening h of the opening h, and on the opposite side of the flat portion having the screw hole 34 of the opening h. Has an engaging groove 37 formed on the wall surface, with which the other end of the printed circuit board 32 having no through hole 36 is engaged. In addition, 3 in FIG.
Reference numeral 8 denotes a terminal pin implanted on the surface of the printed circuit board 32, which is connected to the control circuit via a connection holder and a lead wire (not shown).

The present invention is constructed as described above, and when assembling the electric motor 20, the coil bobbin 22a, around which the coil 22 is wound, is placed above the stator core 21 via the iron core 23 for yoke. Installation, then rotor insertion hole 2
4 has a rotor 26 inserted therein, and the rotor shaft 2 of the rotor 26
Bearings a and b are press-fitted in predetermined positions from both sides of 7, and a disk-shaped permanent magnet 31 is fixed to one end portion e of the rotor shaft 27. Next, the brackets 28 and 29 are brought into contact with the front and rear surfaces of the stator core 21, and the bearings a and b are fitted into the bearing support cylinders c and d. As a result, one of the rotor shafts 27 projects outward from the bracket 28 through the insertion hole 28a, and the other has the permanent magnet 31 and projects into the accommodation part f of the bracket 29. Bracket 28,2
9 is fastened to the stator core 21 by using the tightening bolts 30 while being in contact with the stator core 21.

Next, as shown in FIGS. 3 and 4, the rear side bracket 29 is provided with a rotational speed detecting element 33 in a flat portion of an opening h above an accommodating portion f accommodating a permanent magnet. As shown in FIG. 4, while mounting the terminal 32 with the terminal pin 38 side facing upward, by engaging the end portion with the engaging groove 37 on the side of the opening portion h, the opening portion of the bracket 29 is formed. Close h. Then, the screw 35 is screwed into the screw hole 34 at the edge of the opening h from the through hole 36 of the printed circuit board 32 so that the printed board 32 is opened at the opening h of the bracket 29.
To be attached to. As a result, the rotation speed detecting element 3
As shown in FIG. 2, 3 can be arranged to face the outer peripheral edge of the permanent magnet 31 with a predetermined space. Further, since the opening portion h of the bracket 29 can be completely covered with the printed circuit board 32 having the rotation speed detecting element 33,
It is possible to reliably prevent dust and the like from entering the space g without using a special lid for the opening h. Further, the surface of the printed circuit board 32 on which the terminal pins 38 are planted is coated with an insulating material such as resin in advance so that, for example, even if dew condensation occurs on the printed circuit board 32, a short circuit accident, a leakage current may occur. Accidents can be prevented.

After the electric motor 20 has been assembled as described above, when electricity is applied to the electric motor 20 to rotate the rotor 26, the permanent magnet 3 housed in the housing portion f of the bracket 29 on the rear side.
No. 1 is attached to the terminal portion e of the rotor shaft 27 so as to face the rotational speed detecting element 33 attached to the printed circuit board 32 covering the opening h above the space g of the accommodating portion f. The speed detection element 33 reliably detects the magnetism of the permanent magnet 31 rotating in synchronization with the rotor 26, and uses a pulse signal proportional to the rotation speed of the rotor 24 as a speed feedback signal, such as a transistor of a control unit (not shown). Output to the switching unit composed of the above, and the switching unit appropriately shifts the timing of on / off control by the feedback signal, whereby the rotation speed of the rotor 26 can be controlled arbitrarily and reliably.

Next, FIGS. 5 to 7 show another embodiment of the mounting structure of the printed circuit board 32 having the rotational speed detecting element 33. In the embodiment shown in FIG. Through holes 36 are bored at both ends, and projections 40, 40 that fit into the through holes 36 are provided at the edges of the opening h above the housing portion f of the bracket 29 so as to project from the printed circuit board 32. At the time of installation, the through holes 36 are provided with projections 40, 4
0 is pierced and mounted on the edge of the opening h, and the heads of the protrusions 40, 40 protruding from the through hole 36 are crushed by a press or the like to mount the printed circuit board 32 on the bracket 29. .

Further, the embodiment shown in FIG.
Protrusions 41, 41 are provided on the back surfaces of both ends of the protrusion 2, and the protrusions 41, 41 are provided at the edge of the opening h above the accommodating portion f of the bracket 29.
Fitting holes 42, 42 for fitting and holding 41 are formed, and the projections 41, 41 are press-fitted into the fitting holes 42, 42 to mount the printed circuit board 32. In the embodiment shown in FIG. 3, a through hole 36 is bored on the printed circuit board 32 side, and a fitting groove 43 for fitting the printed circuit board 32 is provided at the edge of the opening h above the housing portion f of the bracket 29. At the same time, a projection 44 is formed in the fitting groove 43 so as to penetrate the through hole 36 of the printed board 32. The printed board 32 is fitted into the fitting groove 43, and at the same time, the projection 44 is passed through the through hole 36. The printed circuit board 32 is attached to the bracket 29 by crushing the end.
7 to 7 are all printed circuit boards 32.
Is an embodiment in which the bracket can be attached to the bracket 29 in almost one operation.

As described above, in the mounting structure of the rotation speed detecting element 33 of the present invention, the printed circuit board 32 on which the rotation speed detecting element 33 is mounted can be mounted in the opening h of the bracket 29 in almost one operation. With this configuration, it is possible to quickly and easily assemble this type of electric motor.

[0021]

Since the present invention is constructed as described above, it has the following effects. (1) According to the present invention, a permanent magnet for detecting the rotational speed of a rotor is arranged in a space behind the bracket away from the rotor or the stator core, and the permanent magnet is provided in the upper opening of this space. The rotational speed detecting element is attached to detect the rotational speed of the rotor so that the rotational speed detecting element rarely malfunctions under the influence of the rotating magnetic field generated during the operation of the electric motor. Therefore, the rotation speed of the rotor can be accurately detected. Moreover, although the permanent magnet is separated from the rotor, it is housed in the space behind the bracket, so the motor does not require any special space for mounting the permanent magnet. It can be miniaturized without extra length.

(2) Further, the printed circuit board on which the rotational speed detecting element is mounted can be easily removed from the opening provided at the upper part of the accommodating portion of the bracket, so that the rotational speed can be detected. Even if the element fails ,
As described above, there is no need to remove the bracket from the electric motor for replacement, and since only the printed circuit board needs to be replaced from the outside, maintenance work for the electric motor can be performed quickly and reliably.

[0023] (3), further, printed circuit board with a rotational speed detection device, the opening in the opening of the bracket
Because it is a structure that is directly attached to close the
It is convenient because it can also serve as a lid for the opening, and the printed circuit board itself can be attached to the projection and the projection is penetrated and held, that is, to the fitting method.
The adoption of fastening means which can be attached in a state close to approximately 1 operation by the mounting and exchange of the rotational speed detection device
Conversion work can be simplified, thereby, the assembling work of the motor itself can be performed easily.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of an electric motor including a rotation speed detecting element mounting device of the present invention.

FIG. 2 is a vertical sectional side view of the electric motor shown in FIG.

FIG. 3 is a perspective view of the bracket showing a state in which a rotation speed detection element is incorporated.

FIG. 4 is a perspective view showing the bracket and the rotation speed detecting element in an exploded manner.

FIG. 5 is a perspective view of a second embodiment showing a mounting state of a bracket and a rotation speed detecting element.

FIG. 6 is a perspective view of a third embodiment showing a mounting state of a bracket and a rotation speed detecting element.

FIG. 7 is a perspective view of a fourth embodiment showing a mounting state of a bracket and a rotation speed detecting element.

FIG. 8 is a vertical cross-sectional side view of an electric motor showing a mounting state of a conventional rotation speed detecting element.

[Explanation of symbols]

 20 Electric Motor 21 Stator Iron Core 26 Rotor 27 Rotor Shaft 28 Bracket 29 Bracket 31 Permanent Magnet 32 Printed Circuit Board 33 Rotational Speed Detection Element 36 Through Hole 40 Protrusion 41 Protrusion 43 Fitting Groove 44 Protrusion a Bearing b Bearing c Bearing Support Tube d Bearing support cylinder e Terminal part f Housing part g Vacancy h Opening

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Bibliography Sho 55-62169 (JP, U) Rikai Hei 1-113566 (JP, U) Rikai Hei 2-103782 (JP, U) Rikai Hei 3- 54352 (JP, U)

Claims (1)

(57) [Scope of utility model registration request] 1. An electric motor having a bracket attached to a stator core and rotatably supporting a rotor inserted in a rotor insertion hole, in a rear part of a bearing support cylinder for fitting and holding a bearing of the bracket. An accommodating portion for accommodating the end portion of the rotor shaft protruding from the bearing is integrally formed with the bearing support cylinder ,
A disk-shaped permanent magnet is fixed to the terminal portion of the rotor shaft and housed in the housing portion, and an opening is provided above the housing portion at a position corresponding to the outer peripheral edge of the permanent magnet. A printed circuit board provided with a rotation speed detecting element corresponding to the outer peripheral edge of the permanent magnet, and
A through hole at the edge of the mouth, or a screw fixed to this through hole
The opening is formed by the fastening means formed by
It was designed so that it could be removably attached when the
A speed detection element mounting device for an electric motor.