JPH09308207A - Brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor effectively insulating and preventing the damage of a rotary position detecting sensor. SOLUTION: The containing groove 38 for containing a stator winding 33 is provided by the outer wall 37b and inner wall 37a protruding in the direction perpendicular to the end face of a stator 30 to the insulator (slot insulator) for insulating the pole of the stator 30. A disposed recess 39 is formed by the inner wall 37, the protective wall 37a located at the rotor 30 side and the insulation wall 37b located at the groove 38 side. A rotating position detecting sensor is positioned in the recess 39 and mounted at the insulator on a wiring board 60 provided with the sensor capable of preventing the damage of the sensor by the contact of the insulator of the winding 33 with the rotor 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless electric motor which detects a rotational position of a rotor by a rotational position detection sensor and supplies a drive current to a stator winding based on the detection signal to drive an electric motor.

[0002]

2. Description of the Related Art Conventionally, a brushless electric motor is widely known which detects a rotational position of a rotor by a rotational position detection sensor and supplies a drive current to a stator winding based on the detection signal to rotate the rotor. There is. In this type of brushless motor, a permanent magnet is arranged on the outer periphery of the rotor, and a driving current is supplied to a stator winding (hereinafter simply referred to as winding) wound around the stator to generate a rotating magnetic field. The rotor is configured to rotate, and in order to generate a predetermined rotating magnetic field by this winding, the rotational position of the rotor is detected, and a drive current is sequentially supplied to the winding based on this detection signal. To do.

The rotation position of the rotor is detected by a rotation position detection sensor (hereinafter simply referred to as a sensor) including a Hall element. The sensor is a winding wound around the rotor. In order to detect an accurate rotational position, it must correspond to a permanent magnet and be as close as possible in order to detect an accurate rotational position. From this, conventionally, the axial length dimension of the rotary shaft of the rotor is longer than the laminated dimension of the laminated core of the stator,
In other words, the outer circumference where the permanent magnets of the rotor are arranged is set to be long enough to secure a sufficient insulation distance from the winding on the end face of the stator, and the rotor is projected from the end face of the stator, that is, the magnetic pole. The sensor is arranged around the protruding rotor so as to correspond thereto, so that an insulation distance between the sensor and the winding can be secured and accurate detection can be performed.

[0004]

SUMMARY OF THE INVENTION As described above, the structure for detecting the rotational position of the rotor in the conventional brushless electric motor is designed to secure the insulation distance between the sensor and the winding and to detect the accurate rotational position. The axial length of the rotor is set to be a predetermined length longer than the laminated dimension of the stator, the outer peripheral end of the rotor is projected from the end surface of the stator, and the sensor is made to correspond to the periphery of the protruding rotor. Since it is configured to be arranged, there is a problem that the axial dimension of the rotor becomes large and the electric motor cannot be downsized.
There is also a problem in that the permanent magnet provided on the rotor is expensive because it requires a large permanent magnet and is not economically preferable.

Also, in this type of brushless motor, a large driving current may flow through the winding for some reason, resulting in abnormal heat generation, which may lead to burning or the like. To prevent this, an abnormal temperature of the winding is required. Although a temperature sensor for detecting rise is provided, conventionally, this temperature sensor is attached by winding the temperature sensor around a winding wire using a tape or the like.
There is a problem that the mounting work is troublesome and the number of assembling steps increases.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and the invention according to claim 1 is a rotary member provided rotatably in a frame and having a permanent magnet on the outer periphery thereof. A stator having a plurality of magnetic poles made of laminated iron cores arranged around the rotor and having a stator winding wound through an insulator for insulating the magnetic poles and housed in the frame; A rotation position detection sensor arranged near the rotor to detect a rotation position of the rotor, and circuit means for supplying a drive current to the stator winding based on a detection signal of the rotation position detection sensor. In a brushless electric motor including: an insulator that insulates the magnetic poles, a storage groove for storing the stator winding is provided by an outer wall and an inner wall that project in the axial direction, and the inner wall has the rotation groove. A protective wall positioned on the side and an insulating wall positioned on the side of the storage groove to form an arrangement recess, and a wiring board provided with the rotational position detection sensor is positioned in the installation recess. And a brushless electric motor attached to the insulator.

According to the first aspect of the present invention having such a structure, the insulating recess for insulating the magnetic poles of the stator is formed by the protective wall located on the rotor side and the insulating wall located on the storage groove side. Since the rotational position detection sensor is located at the position, the effect of ensuring insulation from the stator winding can be obtained without increasing the axial length of the rotor.

According to a second aspect of the present invention, there is provided a brushless motor in which a temperature sensor for detecting the temperature of the stator winding is provided on the wiring board according to the first aspect of the invention.

According to the second aspect of the invention thus constructed, since the temperature sensor is provided on the wiring board, the temperature sensor is attached to the winding by tape or the like as in the prior art. In addition, it has the effect that it can be easily and easily attached.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a case in which an embodiment of the brushless motor of the present invention is applied to an electric blower will be described with reference to FIGS. 1 to 5.

FIG. 1 is a sectional view taken along the axial centerline of the electric blower A. As shown in FIG.
The electric motor 1 includes a fan 50 attached to the electric motor 1. The electric motor 1 is composed of the frame 2, the stator 30, the rotor 40 and the like.

The frame 2 is the main frame 10
And a sub-frame 20 attached to the main frame 10 by the attachment screws 3. The main frame 10 is formed into a bottomed cylinder having an opening 11 at one end side, and a bottom wall 12 thereof is provided with a concave bearing housing portion 13 opening toward the opening 11 side. Further, an exhaust hole 14a is formed in a portion of the peripheral wall 14 located on the bottom wall 12 side. Further, a flange portion 15 provided with a fitting portion 15a for fitting and attaching a fan cover 56, which will be described later, is integrally formed at the peripheral portion of the opening 11, and the flange portion 15 is provided with a screw hole (not shown). Has been.

Next, the sub-frame 20 is formed in a substantially rectangular shape and has a central portion that is open on one side, that is, on the side facing the bottom wall 12 of the main frame 10 and on the other side, as shown in FIG. A bearing accommodating portion 21 is formed in a concave shape by denting the bearing accommodating portion 21 toward each other. Further, ventilation holes 22 (only one is shown) are formed on both sides of the bearing accommodating portion 21. Screw holes 23 are formed in the vicinity, and screw insertion holes (not shown) are formed at both ends (only one end is shown). Then, the screw insertion holes (not shown) formed in the both ends and the flange portion 1 of the main frame 10
The sub-frame 20 and the main frame 10 are joined together by attaching the mounting screws 3 in correspondence with the screw holes (not shown) formed in FIG. 5, and in the state where they are joined, a bridge is formed at the center of the opening 11. Subframe 2
On both sides of 0, substantially semicircular air passage openings are formed by both side edges of the sub-frame 20 and the peripheral edge of the opening 11.

Next, the stator 30 which is press-fitted and attached to the main frame 10 will be described. This stator 3
0 is composed of a laminated iron core 31 formed by laminating a plurality of iron cores 32 formed by punching out a silicon steel plate or the like so as to have a predetermined lamination size, and the iron core 32 has a predetermined number as shown in FIG. (6 in the figure) magnetic poles 32a are formed, and slots 32b for winding the stator winding 33 around the magnetic poles 32a are formed between the adjacent magnetic poles 32a. In addition, a press-fitting portion 32c that is press-fitted into the peripheral wall 14 of the main frame 10 is formed on the outer periphery of the iron core 32 so as to project. The press-fitting portions 32c that are press-fitted into the peripheral wall 14 are adjacent to each other. 32c and surrounding wall 14
A space is formed by being surrounded by and, and this space forms an air passage between the outer circumference of the stator 30 and the inner circumference of the main frame 10. As shown in FIG. 2, the cores 32 are laminated so that the laminated cores 31, that is, the slots 32b of the stator 30 and the end faces of the magnetic poles 32a, that is, the end faces of the stator 30, have heat resistance, that is, high temperature when the electric motor 1 is driven. A slot insulating material 34, which is made of a synthetic resin capable of withstanding the temperature of the stator 30, is provided as an insulator. The slot insulating material 34 is integrated with the slot insulating material 34 on the side of the sub-frame 20. And an annular wall 35 serving as an outer wall and protruding from both end surfaces of the stator 30 in a direction orthogonal to the end surface, that is, in the axial direction, and facing the annular wall 35 at a space inside the annular wall 35 and each magnetic pole 32a. Magnetic pole 3
A plurality of (six in the figure) protruding walls 37 as inner side walls are formed at the tip portion of 2a, that is, at a portion corresponding to the tooth portion.
A housing groove 38 for housing the stator winding 33 is formed between the protruding wall 37 and the annular wall 35 as shown in FIG. Further, the protruding wall 37 located on the side of the bottom wall 12 is provided with a disposing recess 39 in which a sensor formed in a groove shape is disposed. This arrangement recess 3
As shown in FIGS. 1, 3 and 4, reference numeral 9 denotes a protective wall 37a located on the side of the rotor 40 and an insulating wall located on the side of the storage groove 38 by forming a thin groove in the circumferential direction of the protruding wall 37. 37b
By forming a groove, the groove is formed in a U-shaped cross section. Then, as shown in FIG. 3, the bottom wall portion 37c formed in the shape of the narrow groove having the U-shaped cross section.
Is an insulating wall that covers the end face of the magnetic pole 32a, that is, the end face of the stator 30, and is thinly formed. In addition,
The slot insulation 34, the annular wall 35 and the protruding wall 37
May be molded in advance with a synthetic resin having heat resistance and attached to the laminated iron core 31.
It may be formed integrally with the laminated core 31. Further, the disposing groove 39 may be formed in a concave shape, that is, a hole shape, instead of a narrow groove shape. In short, the protection wall 37a located on the rotor 40 side and the insulating wall 37 located on the storage groove 38 side.
It is sufficient that b is formed.

Further, three protrusions 35a and 35b are respectively formed on the annular wall 35 on the side of the bottom wall 12 of the main frame 10, and the protrusions 35a are for mounting to mount a wiring board which will be described later in detail. It is a projection of.

The stator 30 is the stator winding 33.
It is mounted by being press-fitted into the main frame 10 in a state where the wiring board 60 to be described later is mounted and the wiring board 60 described later is mounted.

Next, the rotor 40 has a laminated iron core 43 formed by laminating a plurality of iron cores 42 formed by punching out a silicon steel plate or the like so as to have a predetermined laminated dimension, and the outer periphery of the laminated iron core 43. It is composed of a permanent magnet 44 formed with a predetermined number of poles and a rotating shaft 45 press-fitted into the shaft hole 43a of the laminated iron core 43. A screw 45a for attaching a centrifugal fan 51, which will be described later, is formed at the tip of one end of the rotary shaft 45. Ball bearings 46 and 47 are attached to the rotary shaft 45 by press-fitting the inner rings thereof.

In the rotor 40, ball bearings 46 and 47 mounted on a rotary shaft 45 are housed or fitted in bearing housing portions 13 and 21 formed in the main frame 10 and the sub-frame 20, respectively, with their outer rings prevented from rotating. By doing so, it is rotatably supported and disposed in the frame 2.

Next, the fan 50 is composed of a centrifugal fan 51, a rectifying plate 55, and a fan cover 56 for accommodating the centrifugal fan 51 and the rectifying plate 55. The centrifugal fan 51 has a circular flat plate 52,
It is configured by a mountain-shaped curved plate 53 having a gentle curved surface provided with a suction port 53b in the central portion, a flat plate 52, and a plurality of blades 54 connecting the curved plate 53 at a predetermined distance from each other. A through hole 52a through which the rotary shaft 45 is inserted is formed at the center of the flat plate 52. Although not shown, a plurality of air passage openings are formed in the outer periphery of the straightening vane 55, and a circular recessed portion 55a is formed in the center portion. The recessed portion 55a has a bearing for the sub-frame 20. Storage 21
Is formed with a fitting hole 55b which is fitted to the outer peripheral portion of the. A through hole 55c corresponding to the screw hole 23 formed in the sub-frame 20 is formed in the recess 55a.
Further, the fan cover 56 is formed in a bottomed cylindrical shape having a lower opening in the figure, and a bottom wall thereof, that is, a surface facing the curved plate 53 is formed in a shape along the curved surface of the curved plate 53. In the center thereof, the suction port 5 is formed corresponding to the suction port 53b formed in the curved plate 53.
6a is formed, and the inner peripheral wall in the vicinity of the opening of the annular wall 56b is a fitted portion that fits into the fitting portion 15a formed in the flange portion 15 formed in the main frame 10.

The fan 50 is mounted in the assembled state of the electric motor 1. That is, the sub-frame 2 with the electric motor 1 assembled.
First, the straightening vane 55 is arranged so that its through hole 55c corresponds to the screw hole 23 of the sub-frame 20, and the screw 4 is fastened and attached to the screw hole 23. Next, the centrifugal fan 51 is clamped by the mounting plates 57, 57 on the flat plate 52, and is mounted on the screw 45a of the rotary shaft 45 by the nut 59 via the washer 58. Next, the fan cover 56 is attached to the centrifugal fan 51 and the rectifying plate 5.
5, the fitted portion is fitted and fitted to the fitting portion 15a.

Next, a wiring board 60 is attached to the annular wall 35 located on the bottom wall 12 side of the main frame 10. As shown in FIG. 5, the wiring board 60 is formed in a substantially disc shape, a through hole 61 is formed in the central portion for penetrating the rotation shaft 45 of the rotor 40, and the annular wall is formed on the outer peripheral portion. 35 are provided with three notches 62 into which the mounting protrusions 35 a fitted.
After fitting a, heat is applied to the head of the mounting projection 35a to melt the wiring board 60, so that the wiring board 60 is fixed to the annular wall 35.
It can be attached to. Also, the wiring board 6
No. 0 is installed in the installation recess 39 and the permanent magnet 4
Hall element as a sensor for detecting the position of the rotor 40 via the sensor 4, that is, a rotational position detection sensor (Hall I
C) 63 and temperature sensor 64 are attached. Further, the wiring board 60 is provided with a pin 65, the end portion 33 a of the winding 33 and the lead wire 70 are connected to the pin 65, and the hall element 63 is provided on the wiring board 60. It is connected to a lead wire 71 made of a flexible substrate via a printed wiring. And
The lead wire 70 and the lead wire 71 made of a flexible substrate are inserted into a protective tube 73 (see FIG. 1) and drawn out from an exhaust port 14a provided in the main frame 10 to the outside, and a circuit provided with a drive circuit (not shown) is provided. Connected to the means. The temperature sensor 64 is provided at a portion located near the end 33a of the winding 33, and the end portion 3 is driven by a driving current flowing through the winding 33.
Although the portion 3a also generates heat, the heat generation, that is, the temperature is detected by the temperature sensor 64, and when the winding 33 abnormally generates heat at a predetermined temperature or higher, that is, the drive current, the supply of the drive current is stopped, and the electric motor is It is intended to prevent burnout of item 1 and the like. The temperature sensor 64 may be arranged in contact with or close to the winding 33 housed in the housing groove 38 as shown by the dotted line in FIG.

The Hall element 63 is located in the disposing recess 39 when the wiring board 60 to which the Hall element 63 is attached is attached to the annular wall 35. As a result, the insulation of the Hall element 63 from the winding 33 is ensured by the insulating wall 37b, and the vibration of the electric blower A or an unexpected impact force from the outside is applied by the protective wall 37a. Even if the Hall element 63 moves, the protective wall 37a can reliably prevent the contact with the rotor 40, so that the Hall element 63 can be prevented from being damaged. In addition, the arrangement recess 3
By providing 9 on the end face of the stator 30, the Hall element 6
3 is provided to insulate the winding 33 from contact with the rotor 40, and the disposing recess 39 is the end face of the stator 30, that is, the magnetic pole 32a formed on the stator 30 and on the rotor side. Since it is formed at a position close to the end surface of the stator 30 and the rotor 40, it is not necessary to increase the axial length of the rotor as in the conventional case. It is possible to solve the problem that the size of the electric motor cannot be reduced and the problem that the permanent magnet provided in the rotor has to be made large as in the conventional case.

Since the temperature sensor 64 is provided on the wiring board 60, the temperature sensor 64 can be attached easily and easily as compared with the conventional method in which the temperature sensor is attached to the winding with tape or the like. It can be simple.

In the above embodiment, the annular wall 35 as an insulator is formed integrally with the slot insulating material 34, but this is formed separately from the slot insulating material 34 and the stator is formed. It may be configured to be attached to the end face portion of 30. However, when the structure is formed integrally with the slot insulating material 34 as in the above-described embodiment, there is an advantage that the number of parts is reduced and the assembly is easy as compared with the case where it is formed separately.

In the above embodiment, the brushless electric motor is used as the electric blower. However, it goes without saying that the brushless electric motor can be used alone and can be used for other electric equipment. It is possible.

[0026]

According to the first aspect of the invention configured as described above, the insulator for insulating the magnetic poles of the stator is formed by the protective wall located on the rotor side and the insulating wall located on the storage groove side. Since the rotation position detection sensor is located in the provided recess, it has the effect of ensuring insulation from the stator winding without increasing the axial length of the rotor. is there.

Further, according to the second aspect of the present invention, since the temperature sensor is provided on the wiring board, the temperature sensor is attached to the winding with tape or the like as in the conventional case. It has an effect that the mounting can be made easy and simple.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an electric blower showing an embodiment of the present invention, taken along the axial center line.

FIG. 2 is a diagram showing the stator with the slot insulating material according to the above-described embodiment attached, (A) being a top view thereof;
(B) is a side view and (C) is a bottom view.

FIG. 3 is a cross-sectional view showing a recessed portion provided in the embodiment (a cross-sectional view taken along line XX in FIG. 2C).

FIG. 4 is a perspective view showing a recessed portion provided in the embodiment.

FIG. 5 is a diagram showing the wiring board of the above embodiment,
(A) is a top view, (B) is a side view, and (C) is a bottom view.

[Explanation of symbols]

 A electric blower 1 electric motor 2 electric motor frame 10 main frame 20 sub-frame 30 stator 32a stator magnetic pole 34 slot insulating material (insulator) 35 annular wall (outer wall) 37 protruding wall (inner wall) 37a protective wall 37b insulation Wall 38 Storage groove 40 Rotor 60 Wiring board 63 Hall element (rotational position detection sensor) 64 Temperature sensor

Claims (2)

[Claims] 1. A rotor provided rotatably in a frame and having permanent magnets arranged on the outer periphery thereof, and a plurality of magnetic poles composed of a laminated iron core and arranged around the rotor, and the magnetic poles are insulated. A stator winding wound through the insulator and housed in the frame, and a rotational position detection sensor arranged near the rotor to detect a rotational position of the rotor, In a brushless electric motor comprising: circuit means for supplying a drive current to the stator winding based on a detection signal of the rotational position detection sensor,
An insulator for insulating the magnetic poles is provided with an accommodating groove for accommodating the stator winding by an outer wall and an inner wall which are provided so as to project in the axial direction, and the inner wall has a protective wall located on the rotor side and the protective wall. An arrangement recess is formed by the insulating wall positioned on the storage groove side, and a wiring board provided with the rotation position detection sensor is attached to the insulator with the rotation position detection sensor positioned in the arrangement recess. Brushless electric motor. 2. A temperature sensor for detecting the temperature of the stator winding is provided on the wiring board.
Brushless electric motor as described.