JP3017424U - Brushless DC motor - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a brushless DC motor that can reduce the size of a printed circuit board while maintaining the positioning effect of each positioning hole without increasing the cost. [Structure] An annular insulating spacer is provided at the axial end of the stator core of the brushless DC motor body, and a printed circuit board 5 on which a control circuit of the brushless DC motor body is mounted is brought into contact with the end surface of the insulating spacer. The printed circuit board 5 is provided with a plurality of positioning holes 7 adjacent to the central hole 6 through which the rotary shaft of the rotor of the brushless DC motor body is passed. The printed circuit board 5 is provided with slits 13 each reaching the central hole 6 from each positioning hole 7 with a width smaller than the diameter of the positioning hole 7. Positioning protrusions projecting from the end surfaces of the insulating spacers are inserted into these positioning holes 7 to position the printed circuit board 5. The printed circuit board 5 is fixed to the insulating spacer at the fixing portion.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a brushless DC motor, and in particular, a control circuit for the brushless DC motor body is mounted on an end surface of an annular insulating spacer provided at an end portion of a brush core of the brushless DC motor body in the axial direction. The present invention relates to an improvement of a brushless DC motor to which a printed circuit board is attached.

[0002]

[Prior art]

 In the brushless DC motor, as shown in FIGS. 2A and 2B, a stator 3 having a structure in which a stator coil 2 is wound around each pole portion 1a of a stator core 1 via a bobbin (not shown), The brushless DC motor body is composed of a rotor and a rotor. An annular insulating spacer 4 is integrally formed with a bobbin (not shown) or mechanically connected to the bobbin at the axial end of the stator core 1 of the brushless DC motor body. A printed circuit board 5 on which a control circuit of the brushless DC motor body is mounted is brought into contact with the end surface of the insulating spacer 4, and a central hole 6 through which the rotary shaft of the rotor of the brushless DC motor body is passed is attached to the printed circuit board 5. A plurality of positioning holes 7 are provided adjacent to each other, and the positioning protrusions 8 projecting from the end surface of the insulating spacer 4 are inserted into these positioning holes 7 to position the printed circuit board 5. . The printed circuit board 5 is fixed to the insulating spacer 4 by the fixing portion 9. In the fixed portion 9, the printed circuit board 5 is brought into contact with the tip surfaces of a plurality of boss portions 10 projecting from the end surface of the annular insulating spacer 4 at different positions in the circumferential direction, and at the position of each boss portion 10. A screw 11 that is inserted through a hole of the printed circuit board 5 is screwed into each boss 10. Reference numeral 12 is an electronic component mounted on the printed circuit board 5.

In the brushless DC motor having such a structure, if each positioning hole 7 of the printed circuit board 5 is closer to the central hole 6 side and the distance between the positioning hole 7 and the central hole 6 is short, the printed circuit board 5 is This is advantageous in terms of space when mounting the electronic component 12, and the printed board 5 can be made smaller.

[0004]

[Problems to be solved by the device]

 However, if each positioning hole 7 is too close to the central hole 6 in the conventional structure, each positioning hole 7 is not cracked or chipped between the central hole 6 and the positioning hole 7 when punching with a die for drilling each positioning hole 7. As a result, the positioning effect of each positioning hole 7 is lost, and repair work is required in a separate process, resulting in a problem of increased cost.

An object of the present invention is to provide a brushless DC motor that can reduce the size of a printed circuit board while maintaining the positioning effect of each positioning hole without increasing the cost.

[0006]

[Means for Solving the Problems]

 According to the present invention, an annular insulating spacer is provided at the axial end of the stator core of the brushless DC motor body, and a printed circuit board on which the control circuit of the brushless DC motor body is mounted is provided at the end surface of the insulating spacer. The printed circuit board is provided with a plurality of positioning holes adjacent to the central hole through which the rotary shaft of the rotor of the brushless DC motor body is passed, and the positioning holes project from the end face of the insulating spacer. A brushless DC motor having a structure in which a locating protrusion is inserted to position a printed circuit board and the printed circuit board is fixed to an insulating spacer at a fixing portion is targeted for improvement.

The brushless DC motor of the present invention is characterized in that the printed board is provided with slits reaching from the respective positioning holes to the central hole with a width smaller than the hole diameter of these positioning holes.

[0008]

[Action]

 In this way, by providing the printed circuit board with slits that reach the central hole from each positioning hole with a width smaller than the hole diameter of these positioning holes, the size of the printed circuit board can be reduced while maintaining the positioning effect of each positioning hole. The brushless DC motor can be downsized. Further, according to this structure, repair work of the printed circuit board is not necessary, so that cost increase can be prevented.

[0009]

【Example】

 FIG. 1 shows an embodiment of a brushless DC motor according to the present invention. The parts corresponding to those in FIGS. 2A and 2B described above are designated by the same reference numerals.

In the brushless DC motor of this embodiment, the printed circuit board 5 is provided with the slits 13 extending from the respective positioning holes 7 to the central hole 6 with a width smaller than the diameter of these positioning holes 7.

As described above, when the slits 13 reaching the central hole 6 from the positioning holes 7 are provided in the printed circuit board 5 with a width smaller than the hole diameters of the positioning holes 7, the positioning holes inserted in the positioning holes 7 respectively. Since the protrusion 8 (see FIG. 1) cannot move to the slit 13 side, the printed circuit board 5 can be downsized while maintaining the positioning effect of each positioning hole 7, and the brushless DC motor can be downsized.

Further, according to this structure, repair work of the printed circuit board 5 is not required, and therefore cost can be prevented.

[0013]

[Effect of device]

 In the brushless DC motor according to the present invention, the printed circuit board is provided with the slits reaching the central holes from the respective positioning holes with a width smaller than the hole diameters of these positioning holes. Since it cannot be moved to the slit side, the printed circuit board can be downsized while maintaining the positioning effect of each positioning hole, and the brushless DC motor can be downsized.

Further, according to this structure, since it is not necessary to repair the printed circuit board, cost increase can be prevented.

[Brief description of drawings]

FIG. 1 is a bottom view of an essential part of an embodiment of a brushless DC motor according to the present invention.

2A is a side view of a conventional brushless DC motor, and FIG. 2B is a bottom view of the brushless DC motor shown in FIG.

[Explanation of symbols]

 1 Stator Core 1a Pole Part 2 Stator Coil 3 Stator 4 Insulating Spacer 5 Printed Circuit Board 6 Center Hole 7 Positioning Hole 8 Positioning Protrusion 9 Fixing Part 10 Boss 11 Screw 12 Electronic Component 13 Slit

Claims (1)

[Scope of utility model registration request] 1. An annular insulating spacer is provided at an axial end of a stator core of a brushless DC motor body,
A printed circuit board mounting a control circuit of the brushless DC motor body is brought into contact with an end surface of the insulating spacer,
The printed circuit board is provided with a plurality of positioning holes adjacent to a central hole through which the rotating shaft of the rotor of the brushless DC motor body is passed, and the positioning protrusions protruding from the end surface of the insulating spacer are provided in these positioning holes. In the brushless DC motor in which the printed circuit board is inserted and positioned, and the printed circuit board is fixed to the insulating spacer at a fixing portion, the printed circuit board has a slit reaching from the positioning hole to the central hole. A brushless DC electric motor having a width smaller than the hole diameter.