JPH0629375U - Motor speed detection element mounting device - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a speed detection element mounting device for an electric motor, which prevents displacement of a printed circuit board on which a hall element is mounted, and enables quick and easy mounting work. With the goal. A U-shaped accommodating portion 30b for covering and accommodating a rotary disk 31 made of a permanent magnet fixed to an end of a rotor shaft 27 protruding from a bracket 29, and a hole at a position corresponding to the rotary disk 31. A cover body 30 having an element 35 and a printed circuit board 32 removably attached to the opening f of the housing portion 30b is brought into contact with the rear part of the bracket 29, and the cover body 30 is attached. It is characterized in that a speed detecting element mounting device is configured by mounting the stator core 21 via the bracket 29.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement in a mounting structure of a speed detection element that detects the rotation speed of an electric motor.

[0002]

[Prior art]

 Conventionally, for example, in an oil fan heater and various cooling and heating devices, an electric motor used as a blower for sending hot air or cold air is capable of continuously changing the rotation speed of the electric motor in order to improve the blowing efficiency. This allows the air flow rate to be automatically adjusted according to the room temperature.

In general, when changing the rotation speed of an electric motor, when a permanent magnet is not used for the rotor of the electric motor, a rotating disc made of a permanent magnet is fixed to the rotor shaft of the rotor to fix the electric motor. During operation, the magnetism (N pole / S pole) of the rotating disk (permanent magnet) is detected as a pulse signal proportional to the rotation speed of the rotor by, for example, a Hall element, and this pulse signal is used as a speed feedback signal. As a result, the rotation speed of the electric motor is arbitrarily controlled by outputting the speed control circuit section to a switching section composed of a transistor and the like, and performing on / off timing control of the switching section according to the speed feedback signal.

Next, as an electric motor to which the rotational speed detecting element is attached, various structures have been conventionally proposed, and one embodiment thereof will be described with reference to FIG. 8, where 1 is a stator core of the electric motor. A bobbin 2 around which a coil is wound is attached to the lower part of the bobbin 2 and a rotor 4 having a rotor insertion hole 3 is rotatably inserted in the upper part thereof. Reference numerals 5 and 6 are brackets accommodating bearings 8 that rotatably support the rotor shaft 7 of the rotor 4, and the rotor 4 is inserted into the rotor insertion hole 3 of the stator core 1 and 7 is inserted into the bearing 8 and brought into contact with the front and rear surfaces of the stator core 1, and in this state, the brackets 5 and 6 are fixed to the stator core 1 by using tightening screws. 4 is rotatably supported in the rotor insertion hole 3. Reference numeral 9 denotes a rotary disk made of a permanent magnet fixed to the rotor shaft 7 of the rotor 4 in the bracket 6 attached to the rear side (rightward in FIG. 8) of the electric motor, and 10 denotes the rotary disk 9 Is a Hall element for detecting the rotation speed of the electric motor attached to the bracket 6 corresponding to the peripheral edge of the.

Then, the hall element 10 for detecting the rotation speed, as shown in FIG. 8, punches a notch hole 11 in the bracket 6 at a position corresponding to the rotating disc 9 in the rear bracket 6. With the Hall element 10 inserted in the cutout hole 11, the printed circuit board 12 on which the hall element 10 is mounted is mounted on the bracket 6 at the peripheral edge of the cutout hole 11 so as to face the peripheral edge of the rotary disk 9. Let's be placed close to each other. Reference numeral 13 denotes a terminal pin implanted on the printed circuit board 12, which is connected to the Hall element 10 for detecting the rotation speed through a lead wire having a terminal (not shown) for connecting the terminal pin 13 to the terminal pin 13 by itself. , Is connected to a speed control circuit unit (not shown).

[0006]

[Problems to be solved by the device]

 As described above, in the electric motor equipped with the hall element 10, when the rotor 4 itself is not formed by a permanent magnet, that is, the rotary disk 9 made of a permanent magnet is mounted on the rotor shaft 7. When configured, the Hall element 10 is located as far as possible from the rotor 4 or the like in order to prevent malfunction due to the influence of the rotating magnetic field generated from the rotor 4 or the stator core 1 during operation of the electric motor. It was necessary to install it at. However, in this case, as is apparent from FIG. 8, the rear side bracket 6 for accommodating the rotating disk 9 must have a relatively large axial dimension as compared with the front side bracket 5. As a result, since the axial length of the electric motor is inevitably long, the electric motor itself becomes large and it is difficult to adapt it to the equipment used, which is a major factor that hinders the miniaturization of the equipment used. Was becoming.

Further, the rear side bracket 6 has to be specially punched with a notch hole 11 for inserting the Hall element 10 in the peripheral edge thereof, so that not only is it troublesome to process, If the position of the notch hole 11 itself is deviated, the Hall element 10 and the rotating disk 9 may be deviated, and the rotation speed of the electric motor may not be accurately detected. Moreover, since the printed circuit board 12 on which the hall element 10 is mounted is attached to the periphery of the bracket 6 by using a screw or the like, it takes a lot of time to attach the printed circuit board 12 to improve the mass productivity and the automatic assembly of the electric motor. It was a hindrance factor.

In view of the above-mentioned various problems, the present invention solves the problems of the conventional technique without specially processing the bracket itself, and eliminates the influence of the rotating magnetic field to achieve accurate correction. An object of the present invention is to provide a device for mounting a rotation speed detection element of an electric motor, which enables detection of the rotation speed.

[0009]

[Means for Solving the Problems]

 SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a structure in which a rotor shaft is made to protrude from one of a pair of brackets that rotatably supports a rotor by a certain length, and a permanent magnet is used at the protruding end. A rotating disk is fixedly attached, and a cover body having a U-shaped vertical cross-section with a part of the peripheral edge opened is attached to the rear part of the bracket so as to cover the rotating disk. A mounting groove for mounting a printed circuit board equipped with a Hall element is provided in the opening of the cover body, and this printed circuit board is inserted into the mounting groove with the Hall element facing the peripheral surface of the rotating disk. Thus, the printed circuit board provided with the Hall element is attached to the bracket in a non-removable manner, and its operation is as follows.

[0010]

[Action]

 Since the present invention is configured as described above, by inserting the printed circuit board into the mounting groove provided in the cover body, it is possible to simply provide the bracket with the fastening member such as a screw without special use. As a result, the work of mounting the printed circuit board can be performed quickly and easily.

Further, since the printed circuit board can be mounted in contact with the rear surface of the bracket by mounting using the cover body, it is possible to prevent the printed circuit board from being removed from the mounting groove. In addition to being able to reliably prevent it, the position shift of the Hall element is eliminated, and it is possible to surely prevent such a defect that the speed detection of the electric motor cannot be accurately performed due to the position shift or the like.

[0012]

【Example】

 An embodiment in which the present invention is applied to a shading coil type electric motor will be described below with reference to FIGS. In FIG. 1 to FIG. 3, 20 is a Kumatori coil type induction motor (hereinafter referred to as “motor”), 21 is a stator core of the motor 20, and a coil bobbin 22a around which a coil 22 is wound is provided under the stator core. It is attached via an iron core 23 for a yoke which is fitted to the rotor 21, and is provided with a rotor insertion hole 24 on the upper part thereof, and the rotor insertion hole 24 has a peripheral edge position on the periphery thereof. In the above, a pair of rake coils 25 are wound around the stator core 21 so as not to project into the rotor insertion hole 24. Reference numeral 26 is a rotor rotatably inserted and held in the rotor insertion hole 24, and 27 is a rotor shaft attached to the rotor 26 by crimping or the like. 28 and 29 are front and rear brackets that are attached to the front and rear portions (left and right direction in FIG. 3) of the stator core 21 with the rotor insertion hole 24 in between, and the central portions of these brackets 28 and 29. As shown in FIG. 3, bearing supporting cylinders c and d for fitting and holding the bearings a and b such as ball bearings are formed to bulge integrally with the brackets 28 and 29. Reference numeral 30 denotes a synthetic resin cover body having a substantially U-shaped vertical cross section which covers the rear part of the bearing support cylinder d of the rear bracket 29, and the structure thereof is open to one side as shown in FIG. A U-shaped fitting portion 30a which opens the mouth portion f and fits into the rear portion of the bearing support cylinder d; and a longitudinal cross-section with a step X inside the fitting portion 30a on the rear side thereof. And a housing portion 30b for housing a rotating disk 31 made of a permanent magnet, which is formed in a U shape, and a mounting groove for mounting the printed circuit board 32 in the opening portion f of the fitting portion 30a. 33 is formed integrally from the fitting portion 30a to the housing portion 30b.

When mounting the brackets 28 and 29, the brackets 28 and 29 are attached to the bearings a and b from both sides of the rotor shaft 27 of the rotor 26 inserted in the rotor insertion hole 24 of the stator core 21. The brackets 28 and 29 are brought into contact with the end faces of the stator core 21 with the rotor shaft 27 protruding from the insertion holes 28a and 29a of the bearing support cylinders c and d, and then the rear portions In a state where the fitting portion 30a of the cover body 30 is fitted to the rear portion of the side bracket 29, the brackets 28 and 29 and the cover body 30 are respectively joined to the arm portions g and h as shown in FIG. The rotor 26 is rotatably held in the rotor insertion hole 24 by integrally tightening the stator core 21 with the tightening bolts 34 at the ends in the length direction.

Next, 35 corresponds to the outer peripheral edge of the rotary disc 31 fixed to the terminal portion e of the rotor shaft 27 protruding from the insertion hole 29 a of the rear bracket 29, and the back surface of the printed circuit board 32. 3 shows a Hall element for detecting the rotation speed of the electric motor 20 mounted together with a capacitor (not shown), and 36 is a connector mounted on the surface of the printed circuit board 32, which is a speed control circuit section via a lead wire (not shown). Connected to.

Next, the printed circuit board 32 provided with the hall element 35 and the connector 36 has its upper end in a state where the connector 36 is directed to the outside of the opening f of the cover body 30 (leftward in FIG. 4). As shown in FIG. 3, the Hall element 35 is inserted into the mounting groove 33 of the cover body 30 by inserting it into the mounting groove 33 in a state where the opening on the housing portion 30b side is closed to a position where the step portion X of the fitting portion 30a is fitted. Can be mounted at a predetermined interval while being opposed to the outer peripheral edge of the rotary disc 31.

Next, in assembling the electric motor 20, the coil bobbin 22 a around which the coil 22 is wound is attached to the lower portion of the stator core 21 via the iron core 23 for yoke. Subsequently, the rotor 26 is inserted into the rotor insertion hole 24, and the bearings a and b are press-fitted into the rotor shaft 27 of the rotor 26 from both sides thereof at predetermined positions. Brackets 28 and 29 are brought into contact with the front and rear surfaces of the stator core 21, and the rotor shaft 27 is projected from the through holes 28a and 29a of the bearing support cylinders c and d as shown in FIG. , D are fitted with the bearings a, b, and a rotary disc (permanent magnet) 31 is fixed to one end e of the rotor shaft 27 protruding from the insertion hole 29a of the bearing support cylinder d. After that, the printed circuit board 32 is inserted into the mounting groove 33 of the opening f of the cover body 30 up to a position matching the step X, as shown in FIG. 4, with the hall element 35 facing the rotating disc 31 side. Then, after closing the opening f (on the housing portion 30b side) of the cover body 30 by the printed circuit board 32 shown by the chain double-dashed line in FIG. 4, as shown in FIG. 2 and FIG. The cover body 30 with the printed circuit board 32 inserted in the mounting groove 33 is placed on the rear part of the bearing support cylinder d from the fitting portion 30a side with the connector 36 of the printed circuit board 32 facing downward, and the tightening bolt 34 is attached. The brackets 28 and 29 and the cover body 30 are integrally fastened to the stator core 21 by using the same.

After the electric motor 20 is assembled as described above, when the electric motor 21 is operated by energization, the rotating disk 31 accommodated in the accommodating portion 30 b of the cover body 30 is inserted into the mounting groove 33 of the cover body 30. Since the Hall element 35 is mounted on the end portion e of the rotor shaft 27 so as to face the Hall element 35 mounted on the printed circuit board 32, the Hall element 35 reliably detects the magnetism of the rotating rotary disk 31. , A pulse signal proportional to the rotation speed of the rotor 26 is output as a speed feedback signal to a switching unit (not shown) including a transistor of a speed control circuit unit, and this switching unit is turned on / off according to the speed feedback signal. By performing the above timing control, the rotation speed of the rotor 26 can be controlled arbitrarily and accurately.

Next, FIGS. 6 and 7 show an example in which the device of the present invention is applied to an electric motor 37 using cylindrical brackets 40 and 40 a, and 38 is a stator core around which a coil 39 is wound. , And is housed and held by a pair of brackets 40, 40a that are press-fitted from both sides in the axial direction. Reference numeral 41 denotes a rotor, and a rotor shaft 41a is rotatably supported by a bearing 43 in a bearing tube 42, 42a recessed in the central portion of the bracket 40, 40a, whereby the rotor core 38 is inserted into the rotor. It is rotatably held in the hole 38a.

Then, as shown in FIG. 6, a rotary disc (permanent magnet) 45 is fixed to the end portion of the rotor shaft 41a protruding from the insertion hole 44 formed in the bearing cylinder 42a of the one bracket 40a. As described above, the rotating disc 45 has the cover body 30 in which the printed circuit board 32 is inserted from the fitting portion 30a to the housing portion 30b on the opening f side thereof, as shown in FIG. When the printed circuit board 32 is screwed to the bracket 40a by using the printed circuit board 32, the printed circuit board 32 can be positioned in contact with the flat surface of the rear portion of the bearing tube 42a of the bracket 40a. The present invention can be realized even if the cover body 30 is attached to the electric motor 37 using 40 and 40a.

[0020]

[Effect of device]

 According to the present invention, a permanent magnet rotating disk is attached to the end of the rotor shaft protruding from the bearing supporting cylinder of one bracket, and a longitudinal cross-section is provided at the rear part of the bearing supporting cylinder equipped with this rotating disk. A printed circuit board provided with a Hall element at a position facing the rotating disc is detachably provided in an opening of the U-shaped accommodating portion, and the rotating disc is covered and accommodated by the accommodating portion. Since the cover element is attached to the stator core together with the bracket having the bearing support cylinder, the Hall element for detecting the rotation speed of the electric motor should be installed away from the rotor. As a result, the Hall element can smoothly and satisfactorily maintain the rotation speed detection function without being influenced by the rotating magnetic field, and thus the speed of the electric motor can be accurately detected. Moreover, since the cover body to which the hall element is attached can be attached to the stator core integrally with the bracket without using a special tightening member, the work of attaching the hall element can be simplified.

Further, the printed circuit board detachably attached to the cover body is brought into contact with the rear portion of the bearing supporting cylinder of the bracket, so that the printed circuit board serves as a stopper, and the printed circuit board serves as the opening portion of the cover body. Since it can be securely prevented from being pulled out of the rotor and the hole element can be positioned accurately, it is mounted on the rotating disk made of a permanent magnet fixed to the end of the rotor shaft and on the back surface of the printed circuit board. It becomes possible to arrange the Hall element and the Hall element always facing each other, and as a result, the rotation speed of the electric motor can be detected smoothly and satisfactorily and accurately.

Furthermore, since the cover body is configured to be fitted and attached using the bearing support cylinder of the bracket, the bracket is provided with a notch hole for inserting a Hall element and a permanent magnet as in the conventional case. There is no need to provide any special empty space for housing, and this does not require that the shape and size of the front and rear brackets be different, so all brackets have the same shape and size. Since a motor can be used, it is possible to favorably reduce the size of the electric motor.

[Brief description of drawings]

FIG. 1 is a cutaway front view of an electric motor having a speed detecting element mounting device according to the present invention.

FIG. 2 is a front view of an electric motor including the speed detecting element mounting device of the present invention.

FIG. 3 is a vertical sectional side view of an electric motor including the speed detecting element mounting device of the present invention.

FIG. 4 is an explanatory diagram for explaining a mounting state of a printed circuit board on a cover body.

FIG. 5 is an exploded perspective view showing a bracket and a cover body.

FIG. 6 is a vertical sectional side view of an electric motor according to another embodiment of the present invention.

FIG. 7 is a front view of the electric motor shown in FIG.

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

[Explanation of symbols]

 20 Electric Motor 21 Stator Iron Core 26 Rotor 27 Rotor Shaft 28 Bracket 29 Bracket 30 Cover Body 30a Fitting Section 30b Housing Section 31 Rotating Disc 32 Printed Circuit Board 33 Mounting Groove 35 Hall Element 36 Connector 37 Electric Motor 38 Stator Iron Core 40 Bracket 40a Bracket 41 Rotor 41a Rotor shaft 42 Bearing tube 42a Bearing tube 45 Rotating disk f Opening

Claims (2)

[Scope of utility model registration request] 1. A motor equipped with a pair of brackets mounted on a stator core and rotatably supporting a rotor inserted in a rotor insertion hole, wherein a bearing formed on one side of the bracket is fitted and held. An accommodating portion having a U-shaped cross section for covering and accommodating a rotating disk made of a permanent magnet inserted into the end of the rotor shaft projecting from the bearing supporting tube at the rear part of the supporting tube, and corresponding to the rotating disk. A cover element having a Hall element at a position and a printed circuit board removably attached to the opening of the accommodating portion, abutting on the rotating disk to contact the cover with the bracket. A speed detecting element mounting device for an electric motor, characterized in that it is mounted integrally with the bracket on a stator core through 2. The cover body integrally includes an accommodating portion for accommodating the rotating disk and a fitting portion for mating with the bearing support cylinder with a step, and an opening portion of the accommodating portion. Is provided with a mounting groove for removably engaging and holding the printed circuit board, and one end located on the opening side of the printed circuit board inserted in the mounting groove is brought into contact with the bearing support cylinder for mounting. An apparatus for mounting a speed detecting element of an electric motor according to claim 1.