JPH10295068A - Brushless motor and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brushless motor for positively and inexpensively preventing a rotary shaft from swinging by utilizing a configuration, where a wiring pattern is formed for utilizing the substrate of the motor as a circuit substrate, and its manufacturing method. SOLUTION: A stator substrate 2 of a brushless motor 1 is a single body molding between an iron plate 70 and a resin 80. A wide circular part 79 of a wiring pattern 78 that is constituted by one portion of the iron plate 70 is constituted at one-side region for a rotary shaft 60 of a rotor 6. Therefore, since the stator substrate 2 attracts the rotor 6 to one side, a rotary shaft 61 is subjected constantly to a side pressure and does not cause irregular swings, even if a relatively large clearance exists between a combustion oil-less bearing 3 and the rotary shaft 61.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor and a method of manufacturing the same, and more particularly, to a structural technique for stabilizing the rotation of a rotating shaft.

[0002]

2. Description of the Related Art Among various conventional motors, VT
In a capstan motor for R or the like, a stator core is fixed to a motor substrate side which is a base of the motor, and a driving coil is wound around salient poles of the stator core. A bearing is also fixed to the motor substrate side, and the bearing supports a rotating shaft that rotates integrally with the rotor case. A rotor magnet is fixed to the inner peripheral surface of the rotor case so as to face the outer peripheral surface of the stator core, and the rotor rotates by a magnetic force generated between the rotor magnet and the drive coil.

Here, inexpensive sintered oil-impregnated bearings are being used instead of ball bearings. However, since the sintered oil-impregnated bearings have a relatively large clearance between a rotating shaft and the rotor, the rotor rotates. In such a case, an irregular run-out such as a rubbing motion is likely to occur on the rotating shaft. As a technique for preventing such irregular rotation of the rotating shaft, Japanese Utility Model Publication No. 5-10547 discloses a technique in which a region of a yoke plate (iron plate) facing a rotor magnet is subjected to drawing or the like to form a concave portion. There is disclosed an invention in which the rotor is always drawn to one side by forming a convex portion and a magnetic attraction generated between the rotor magnet and the yoke plate. Japanese Utility Model Laid-Open Publication No. 4-58065 discloses that a magnetic powder is applied only to one side of a motor substrate with respect to a rotation center position of a rotor, and is generated between the magnetic powder and a rotor magnet. There is disclosed an invention in which a magnetic attraction force is used to always draw a rotor to one side.

[0004]

However, the above-mentioned 2)
According to one of the inventions, in the method of forming a concave portion or a convex portion by performing drawing processing on the yoke plate, since the unevenness cannot be formed deeper or higher, the magnetic attraction force generated between the rotor magnet and the yoke is reduced. There is a problem that it is not possible to give a great strength. Also, when a wiring pattern is printed on the surface of the yoke plate via an insulating film and is used as a motor substrate, the wiring pattern is peeled off when the unevenness is formed on the yoke plate. There is a problem that such technology cannot be applied. on the other hand,
The method of applying the magnetic substance powder to the motor substrate has a problem that the operation for the method is troublesome.

[0005] In view of the above problems, an object of the present invention is to provide:
Even without using the irregularities formed by drawing on the yoke plate,
In addition, even without adding a new process such as applying a magnetic substance powder, the structure of forming a wiring pattern on the base in order to use the base of the motor as a circuit board makes it possible to make irregular rotation axes. It is an object of the present invention to provide a brushless motor capable of reliably and inexpensively preventing excessive runout, and a method of manufacturing the same.

[0006]

In order to solve the above problems, the present invention provides a driving coil held on a side of a base,
A bearing held on the side of the base, and supported on the side of the base via a rotating shaft rotatably supported by the bearing, the bearing is supported on the base by a magnetic force generated between the drive coil and the rotor magnet. In the brushless motor having a rotor that rotates with the terminal, the base is a terminal portion to which an end of the drive coil is connected by wiring, a wiring pattern extending from the terminal portion, and a region facing the rotor magnet. A magnetic plate and a resin forming a rotor attraction portion that is unevenly distributed in one region with respect to the rotation center position of the rotor and generates a magnetic attraction force for attracting the rotor to the one side with the rotor magnet; Characterized by being formed from an integrally molded product of

In the brushless motor according to the present invention, the region facing the rotor magnet on the side of the base formed of an integrally molded product of the magnetic plate and the resin is provided on one side with respect to the rotation center position of the rotor. A rotor suction part constituted by a part of the magnetic plate is arranged, and the rotor suction part is
A magnetic attraction force is generated between the rotor magnet and the rotor magnet. Therefore, since the magnetic attraction force acting on the rotor magnet varies depending on the location depending on the presence or absence of the rotor attraction portion, the rotor attraction portion pulls the rotor to one side. Therefore, even if there is a relatively large clearance between the bearing and the rotating shaft, the rotating shaft is always in a state of receiving the side pressure, so that irregular running does not occur. In addition, since the strength of the magnetic attraction force acting on the rotor magnet is determined by the presence or absence of the rotor suction portion, it is different from the case where the gap between the rotor magnet and the magnetic plate is widened and narrowed by the unevenness formed by drawing on the magnetic plate. As a result, the magnetic attraction force can be greatly varied. Therefore, irregular running of the rotating shaft can be reliably prevented. Also, the conductive plate material and the resin that constitute the wiring pattern are integrally molded,
When the base is configured as a circuit board, a magnetic plate is used as a plate material, and a part of the magnetic plate constitutes the rotor suction unit. That is, since the rotor suction unit is configured using the process for configuring the base as a circuit board as it is, the number of processes does not increase. Therefore, it is possible to inexpensively prevent the rotation of the rotating shaft of the brushless motor.

In the present invention, a wide circular arc portion corresponding to the shape of the rotor magnet is formed in a part of a region facing the rotor magnet with respect to the wiring pattern,
The wide arc portion may be used as it is as the rotor suction portion.

In the present invention, it is preferable that the magnetic plate is manufactured at low cost by press working.

In manufacturing the brushless motor having such a configuration, a plate material as a raw material of the magnetic plate is subjected to press working to connect the terminal portion, the wiring pattern, and the rotor suction portion to a frame portion. A pressing step of forming, and among the plate members having passed through the pressing step, the terminal portion, the wiring pattern, and the rotor suction portion are housed in a mold, and resin molding is performed in the mold to form a resin molded product. Forming the terminal portion, the wiring pattern, and the rotor suction portion from the frame portion to shape the resin molded product into the base; and forming the drive coil on the base, bearing,
And an assembly process for mounting the rotor. That is, it is not necessary to add a new process such as applying a magnetic substance powder, so that a brushless motor that does not generate irregular runout on the rotating shaft can be manufactured at low cost.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A brushless motor to which the present invention is applied will be described with reference to the drawings.

(Overall Structure) FIGS. 1A, 1B, and 1C
1 is a plan view of a brushless motor 1 to which the present invention is applied, FIG.
It is a fragmentary sectional view in the I 'line.

As shown in FIGS. 1A, 1B and 1C, the brushless motor 1 of the present embodiment is a capstan motor for a VTR, and a stator substrate 2 has a cylindrical projection at the center thereof. 20 are formed. The sintered oil-impregnated bearing 3 is held inside the central hole of the projection 20, and the stator core 4 is fitted outside the projection 20. Each of the salient poles of the stator core 4 has three phases (U phase, V phase, W phase)
Are wound. The rotary shaft 61 of the rotor is rotatably supported on the sintered oil-impregnated bearing 3.
, A rotor case 62 is fixed. A ring-shaped rotor magnet 63 is fixed to the inner peripheral surface of the side surface of the rotor case 62 so as to face the outer peripheral surface of the stator core 4. Therefore, the magnetic force generated between the rotor magnet 63 and the drive coil 5 causes the rotor case 62 to rotate.
Rotates integrally with the rotating shaft 61. Here, a pulley 64 is formed on the upper surface of the rotor case 62.
The brushless motor 1 transmits a driving force via a belt (not shown) wrapped around the brushless motor 4.

(Structure of Stator Substrate 2) FIG.
(B) and (C) respectively show a stator substrate (base / core holder) used in a brushless motor to which the present invention is applied.
Plan view, its sectional view taken along the line III-III ',
FIG. 4 is a cross-sectional view taken along the line IV ′.

In this embodiment, the stator substrate 2 is also used as a circuit substrate for supplying power to the drive coil 5. That is, as shown in FIGS. 2A to 2C, the stator substrate 2 stands up at four locations around the protrusion 20 and ends of the drive coil 5 of each phase (U phase, V phase, W phase). Are connected to one another, and one terminal 74 to which all terminals of the three-phase drive coil 5 are connected by common wiring. Terminal portions 71 to 7 respectively
4, the wiring patterns 75, 76, 77, 7
8 are integrally extended, and the respective wiring patterns 75, 76, 7
External terminal portions 751, 761, 77 are provided at the ends of 7, 78, respectively.
1, 781 and 782 are respectively constituted. These external terminal portions 751, 761, 771, 781, 782
Of these, the external terminal portions 751, 761, 771 of each phase and the common external terminal portion 781 are arranged so as to protrude from one edge 21 of the stator substrate 2, and the common external terminal 782 is It is arranged so as to project from the other edge 22.

The four terminal portions 71 to 74 and 4
Each of the wiring patterns 75 to 78 is formed by press-forming a single iron plate (magnetic plate) and then insert-molding the same, as described later. That is, the stator board 2 is provided with the iron plate 70 (magnetic plate) constituting the four terminal portions 71 to 74 and the four wiring patterns 75 to 78.
And an integrally molded product (insert mold substrate) of a highly heat-resistant resin 80 such as PBT, PPS, or 66 nylon, and almost all of the wiring patterns 75 to 78 are made of resin on the surface of the stator substrate 2. 80
(In FIG. 2 (A), the exposed portion is shaded).

On the front side of the stator substrate 2, reinforcing ribs 89 formed so as to surround the outside of the rotor case 62.
Is protruding. In addition, a thin insulating film is formed on the surface of the stator substrate 2 and the wiring patterns 75 to 7 are formed by the thin insulating film.
8 in some cases.

Here, the formation regions of the four wiring patterns 75 to 78 are arranged so as to be unevenly distributed in one region of the region facing the rotor magnet 63 with respect to the rotation shaft 61 of the rotor 6. . That is, of the four wiring patterns 75 to 78, the wiring pattern 78 for setting the terminal of the drive coil 5 to the common potential is located on one side from the one edge 21 of the stator substrate 2 to the rotating shaft 61 of the rotor. , And reaches the other end 22, of which a portion passing through a region facing the rotor magnet 63 is a wide arc portion 79. Therefore, the rotor magnet 63 and the wide circular arc portion 79 of the wiring pattern 78 face each other with a large area. On the other hand, the other portion of the common wiring pattern 78 is narrow and the other three wiring patterns 75 to 77 are all narrow patterns. In the region excluding, the facing area between the rotor magnet 63 and the wiring patterns 75 to 78 is extremely small.

(Effect of this Embodiment) In the brushless motor 1 configured as described above, since the inexpensive sintered oil-impregnated bearing 3 is used as a bearing for supporting the rotating shaft 61, the inner circumference of the rotating shaft 61 and the sintered oil-impregnated bearing 3 is used. There is a relatively large clearance between the surface. Therefore, with the structure as it is, the rotor 6
When the shaft rotates, the rotating shaft 61 tends to cause irregular runout in the sintered oil-impregnated bearing 3. However, in the present embodiment, in a region facing the rotor magnet 63, a region on one side with respect to the rotation center position (the rotation shaft 61) of the rotor 6 has a wide wiring pattern 78 formed of a part of an iron plate. An arc portion 79 is arranged, and the wide arc portion 79 functions as a rotor attraction portion that generates a magnetic attraction force (indicated by an arrow B) between itself and the rotor magnet 63. Therefore, the magnetic attraction force acting between the stator substrate 2 and the rotor magnet 63 is strong on the side where the wide circular arc portion 79 is located, and does not exist on the opposite side. That is, the magnetic attraction force acting between the stator substrate 2 and the rotor magnet 63 varies depending on the location depending on the presence or absence of the wide circular arc portion 79.
The stator substrate 2 (wide arc portion 79) draws the rotor 6 to one side. As a result, even if there is a relatively large clearance between the sintered oil-impregnated bearing 3 and the rotary shaft 61, the rotary shaft 61 is always in a state of receiving the side pressure as shown by the arrow C. No irregular swing like movement occurs. Moreover, the rotor magnet 6
Since the strength of the magnetic attraction force acting on 3 is determined by the presence or absence of the wide circular arc portion 79 as the rotor suction portion, the magnetic attraction force can be greatly varied.

(Manufacturing Method of Brushless Motor 1) The brassless motor having such a configuration is manufactured by a method described below.

In the method of manufacturing the brushless motor 1 according to the present embodiment, first, a large iron plate is subjected to press working, and as shown in FIG. 3, the terminal portions 71 to 74, the wiring patterns 75 to 77, and the rotor suction A wiring pattern 78 having a wide circular arc portion 79 to be a part is punched out while being connected to a rectangular frame portion 701 (pressing step). Further, the terminal portions 71 to 74 are subjected to processing for erecting them.

Next, of the iron plate 700 that has been subjected to the pressing step, the wiring pattern 78 including the terminal portions 71 to 74, the wiring patterns 75 to 77, and the wide circular arc portion 79 is housed in a mold, and is placed in the mold. To form a resin molded product (molding step). Of course, the terminal portions 71 to 74 are made of a resin 80 so that the coil wiring connection can be performed later.
Do not cover with. In FIG. 3, the outline of the outer periphery of the resin molded product is represented by a dashed line L.

Next, the wiring patterns 75 to 77 and the wiring pattern 78 including the wide circular arc portion 79 are separated from the frame portion 701 at the position shown by the arrow F, and the resin molded product is separated from the stator substrate 2 shown in FIG. (Shaping process).

Next, as shown in FIG.
, The drive coil 5, the sintered oil-impregnated bearing 3, and the rotor 6 are mounted (assembly process).

As described above, since the rotor suction portion (the wide circular arc portion 79) is formed by directly using the process for forming the stator substrate 2 as a circuit board, the number of processes does not increase. Therefore, irregular running of the rotating shaft 61 of the brushless motor 1 can be prevented at low cost. Therefore,
When the brushless motor 1 is mounted on a set as a VTR captan motor, a direction in which a side pressure is applied as indicated by an arrow C in FIG. 1B and a direction in which the belt is pulled on a pulley 64 (arrow E). The brushless motor 1 is arranged in the same direction.

[Other Embodiments] In the above embodiment, the common wiring pattern 78 is provided with a wide circular arc portion 79 serving as a rotor suction portion. A wide circular arc portion 79 serving as a rotor suction portion may be provided.

The portion to be the rotor suction portion may be electrically insulated from any of the wiring patterns 75 to 78. For this purpose, a large iron plate is subjected to press working to form the terminal portions 71 to 74 and the wiring patterns 75 to 78 as shown in FIG. May be formed. In this case, since the wide arc portion 79 (rotor suction portion) is separated from the wiring patterns 75 to 78, the wide arc portion 79 and the frame portion 701 are connected to each other before the insert molding. Connected via
After the insert molding, the connecting portion 702 is cut off at a position indicated by an arrow F. Even in the case of such a configuration, as described with reference to FIG. 1B, the magnetic attraction force acting on the rotor magnet 63 can be increased by the wide circular arc portion 79 (rotor attraction portion).
The rotor 6 is pulled to one side because there is a difference depending on the location depending on the presence or absence. Therefore, even if there is a relatively large clearance between the sintered oil-impregnated bearing 3 and the rotating shaft 61,
Since the rotating shaft 61 is always in the state of receiving the lateral pressure, the same effects as those of the above-described embodiment can be obtained, for example, the irregular running does not occur. Further, even though the wide circular arc portion 79 is separated and independent from the wiring patterns 75 to 78, the process for configuring the stator substrate 2 as a circuit substrate is directly used as in the above-described embodiment. Therefore, it is not necessary to increase the number of manufacturing steps, and the deflection of the rotating shaft 61 of the brushless motor 1 can be prevented at low cost.

Further, the stator substrate 2 may be configured as a part of a chassis of a set (electric product) instead of a base of the motor.

[0029]

As described above, in the brushless motor according to the present invention, the rotation center position of the rotor is located in the region facing the rotor magnet on the side of the base formed of the magnetic plate and the resin. Is characterized in that a rotor suction portion constituted by a part of a magnetic plate is arranged in one region. Therefore, according to the present invention, the rotor suction unit generates a strong magnetic attraction that is strong and weak depending on the location, and draws the rotor to one side. Therefore, even if there is a relatively large clearance between the bearing and the rotating shaft, the rotating shaft is always in a state of receiving the side pressure, so that irregular running does not occur. Further, since the rotor suction unit is configured by directly using the process for configuring the base as a circuit board, the number of processes does not increase.
Therefore, it is possible to inexpensively prevent the rotation of the rotating shaft of the brushless motor.

[Brief description of the drawings]

FIGS. 1A, 1B and 1C are respectively a plan view of a brushless motor to which the present invention is applied, a partial sectional view taken along line II ′, and a partial sectional view taken along line II-II ′. It is.

FIGS. 2A, 2B, and 2C are a plan view of a stator substrate used in a brushless motor 1 to which the present invention is applied, a cross-sectional view taken along a line III-III ′, and a line IV-I thereof.
It is sectional drawing in the V 'line.

FIG. 3 is a plan view showing a state after press working is performed on an iron plate to form the stator substrate shown in FIG. 2;

FIG. 4 is a plan view showing a state after press working is performed on an iron plate to form a stator substrate used in another brushless motor to which the present invention is applied.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 brushless motor 2 stator substrate (base) 3 sintered oil-impregnated bearing 4 stator core 5 drive coil 6 rotor 61 rotating shaft 62 rotor case 63 rotor magnet 64 pulley 70 iron plate (magnetic plate) 71 to 74 terminal portion 75 to 78 wiring pattern 79 wide Arc part of rotor (rotor suction part) 80 Resin 89 Reinforcement rib 700 Iron plate 701 after pressing process Frame part

Claims (4)

[Claims] 1. A driving coil held on a side of a base, a bearing held on the side of the base, and supported on the side of the base via a rotation shaft rotatably supported by the bearing, In a brushless motor having a rotor which rotates on the base by a magnetic force generated between a drive coil and a rotor magnet, the base includes a terminal portion to which an end of the drive coil is connected by wiring, and a terminal extending from the terminal portion. The wiring pattern provided, and the magnetic attraction force which is located in one side area with respect to the rotation center position of the rotor and attracts the rotor to the one side with respect to the rotation center position of the rotor magnet, in the area facing the rotor magnet. A brushless motor comprising an integrally molded product of a magnetic plate and a resin constituting a rotor suction unit generated between the brushless motors. 2. The wiring pattern according to claim 1, wherein the wiring pattern includes a wide arc portion corresponding to the shape of the rotor magnet in a part of a region facing the rotor magnet, and the rotor suction portion is formed by the arc portion. A brushless motor characterized in that: 3. The brushless motor according to claim 1, wherein the magnetic plate is manufactured by press working. 4. The method for manufacturing a brushless motor according to claim 1, wherein a plate material serving as a raw material of said magnetic plate is subjected to press working to form said terminal portion, said wiring pattern, and said rotor suction portion. A pressing step of forming a state connected to a frame portion, and, among the plate members having passed through the pressing step, the terminal portion, the wiring pattern, and the rotor suction portion are housed in a mold, and a resin is formed in the mold. A molding process of forming a resin molded product by performing molding;
A shaping step of shaping the resin molded product into the base by separating the terminal portion, the wiring pattern, and the rotor suction portion from the frame portion, and mounting the drive coil, the bearing, and the rotor on the base; And an assembling process.