JP3438458B2 - Polygon scanner mirror motor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor used for polarization scanning of a laser beam printer used in the field of OA and the like.

[0002]

2. Description of the Related Art In recent years, brushless motors have been mainly used in which a circuit board made of a non-conductive material is attached to a bracket made by die casting or the like.
With the market expansion in the OA field, especially with the widespread use of laser beam printers and the like, it is now necessary to reduce the quality and cost, and instead of a bracket made of die-cast, a control circuit is directly provided on the metal base printed circuit board. On the other hand, when a metal-based printed circuit board is used, the motor drive IC uses a resin-molded flat package type IC, which is advantageous in terms of cost and mounting. Due to an increase in the current flowing through the motor driving IC in the flow and a reduction in the allowable range of the IC, it has been necessary to radiate the IC in terms of operation at high temperature and reliability. Therefore, various methods have been devised.

A conventional brushless motor will be described below. FIG. 3 shows a conventional brushless motor. 3, a rotor assembly including a rotating shaft 3 rotatably supported by a bearing holder 2a holding a bearing or a sintered oil-impregnated bearing 13 and a rotor boss 4 fastened and fixed to the rotating shaft 3, and the rotor boss 4 are shown. A rotor frame 5 is fixedly engaged with the rotor boss 4 at a lower portion of the rotor frame 5, and a rotor magnet 6 is fixed to the rotor frame 5. The stator coil 7 having a plurality of phases at a position facing the rotor magnet 6 is fixed to the metal base printed circuit board 1 via a stator core 8 wound around the rotor magnet 6, and the metal base printed circuit board 1 is a motor driving IC.
10, a resistor 11 and a capacitor 12 are mounted,
A heat radiating plate 15 made of aluminum is bonded and fixed to the upper portion of the motor driving IC 10. Further, the Hall element 9 for detecting the position at the time of rotation is installed, and the C-shaped retaining ring 14 suppresses the fluctuation of the rotor boss 4 in the thrust direction.

The operation of the brushless motor configured as described above will be described below. First, a current flows through the stator coil 7 and a driving force is generated between the stator coil 7 and the rotor magnet 6, and the Hall element 9 detects the polarity of the rotor magnet 6 and switches the current. Starts to rotate. Motor driving IC 10 mounted on the metal base printed board 1
Since heat is generated by a current generated when a driving force or the like is generated, the heat dissipation plate 15 made of aluminum is adhesively fixed.

[0005]

However, in the above conventional configuration, when rotating at high speed, the current flowing through the motor drive IC increases, and the motor drive IC has a resin-molded flat package structure, so the allowable range is small. In order to dissipate heat from the motor drive IC in terms of high temperature operation and reliability, a heat sink must be provided, but aluminum is usually used for that heat sink, and the thermal conductivity coefficient of aluminum is 0.53 cal / cm.・ Since it is sec ・ ℃,
When the resin mold is interposed between the comb frame of the IC and the heat dissipation plate, a sufficient heat dissipation effect cannot be obtained. Moreover, when the material of the heat sink is copper, the thermal conductivity coefficient is 0.941 cal / cm.
・ It will be improved to sec / ° C, but the cost will be higher and it will be necessary to take measures against corrosion. Even if you solve these problems,
Due to the mounting of the motor and the influence of other peripheral parts, the installation space of the heat sink is practically limited, and it is difficult to secure a sufficient area for heat dissipation. Further, there is a problem that a facility for mounting the heat sink is required, which causes an increase in the number of assembling steps, so that the structure of the motor becomes complicated and the quality and cost cannot be reduced.

The present invention solves the above-mentioned conventional problems, and provides a brushless motor capable of efficiently generating heat from a motor driving IC with a simple structure and realizing high quality and low cost. The purpose is to

[0007]

In order to achieve this object, a brushless motor of the present invention has a thermally conductive substance interposed in a gap between a metal base printed circuit board and a motor driving IC, and the thermally conductive substance is made of metal. After applying to the base printed board, a motor drive IC is mounted and fixed with cream solder. The thermal conductive material has a thermal conductivity coefficient of 0.941 cal
You may use the adhesive agent of / cm * sec * (degreeC) or more. In particular, in a polygon mirror scanner motor, a motor driving circuit G provided on the metal base printed circuit board is used.
By arranging staggered lands on the ND pattern and applying cream solder to the lands, the wind caused by the rotation of the polygon mirror can hit the cream solder and enhance the heat dissipation effect of the metal base plate itself.

[0008] The invention according to claim 1 of the present invention, this and the rotation shaft, a rotor boss which is fastened to the outer periphery of the rotary shaft
The polygon mirror fixed on the upper part of the rotor boss and
The rotor frame fixed to the bottom of the rotor boss and this rotor
And <br/> rotor assembly comprising a rotor magnet fixed to Tafuremu, the rotor assembly of the rotor magnet
And a stator assembly for generating and rotating a driving force between the stator assembly and the stator assembly. The stator assembly includes a motor-driving IC having a resin-molded flat package structure, and the driving IC.
With a metal-based printed circuit board on which a chip is mounted
In the scanner mirror motor, the motor driving IC
And a metal base printed circuit board with a heat conductive substance interposed therebetween, a copper foil is provided on a portion of the metal base printed circuit board to which the heat conductive substance is applied , and a motor drive circuit
Staggered lands are arranged in the GND pattern and
Apply cream solder and rotate the polygon mirror.
So that the wind blows on the cream solder applied to the land
A polygon scanner mirror motor characterized by being configured as described above. With this configuration, a heat conductive substance is interposed in the gap between the metal base printed circuit board and the motor driving IC,
By providing a copper foil on the portion of the metal base printed circuit board to which the heat conductive material is applied, heat generated by the motor driving IC at the time of starting the motor can be reduced without using a separate heat dissipation plate. By conducting heat to the foil to radiate heat, it is possible to provide a polygon scanner mirror motor that realizes high-efficiency heat radiation with a simple structure and high quality and low cost.

According to a second aspect of the invention, the IC has thermal conductivity.
Mounted after the substance has been applied to the metal-based printed circuit board.
The poly according to claim 1, which is fixed with cream solder.
A polygon scanner mirror motor, this arrangement, in the polygon scanner mirror motor having a particularly polygonal mirror, by applying a cream solder arranged staggered in Portland GND pattern of the motor control circuit part, a polygon by high-speed rotation The wind from the rotation of the mirror
The cream hits the solder, it is possible to enhance the heat dissipation effect of the metal base plate itself, a poly highly efficient heat radiation effect
It has an effect that a gon scanner mirror motor can be provided.

[0010]

[0011]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. 1 (a) and 1 (b)
In, the rotary shaft 3 is rotatably supported in the inner diameter hole of the sleeve 2b, and the rotor boss 4 is fastened and fixed. A polygon mirror 16 is fixed to the upper part of the rotor boss 4 by a C-shaped retaining ring 18 via a pressing spring 17, and a rotor frame 5 is fixed to the lower part of the rotor boss 4 by meshing with the rotor boss 4. Has a rotor magnet 6 fixed thereto. Further, the metal base printed circuit board 1 has a motor control circuit, and the control circuit is composed of a motor driving IC 10, a resistor 11 and a capacitor 12, and a heat conductive material is provided in a gap between the IC 10 and the metal base printed circuit board 1. 20 is further applied, and the GND pattern 21 of the control circuit portion provided on the metal base printed board 1 has staggered lands 22, and the cream solder 23 is applied to the lands 22. Further, the Hall element 9 for detecting the position at the time of rotation is installed and the retaining member 19 is fixed.

FIG. 2 shows a thermally conductive substance 20 applied in a gap between the motor driving IC 10 and the metal base printed board 1.
The copper foil 24 is provided on the portion of the metal base printed circuit board to which the heat conductive material is applied.

The operation of the polygon mirror scanner motor configured as described above will be described. First, a current flows through the stator coil 7 and a driving force is generated between the stator coil 7 and the rotor magnet 6, and the hall element 9 causes the rotor magnet 6 to move.
Of the rotating shaft 3 by detecting the polarity of the
The polygon mirror 16 starts to rotate via the rotor boss 4 fastened to and starts polarization scanning. The motor driving IC 10 mounted on the metal base printed circuit board 1 generates heat generated at startup through the heat conductive material 20 applied to the gap between the IC 10 and the metal base printed circuit board 1 to cause the metal base printed circuit board 1 to operate. The heat dissipation effect can be enhanced by directly radiating heat to the copper foil 24 of No. 1 and the heat conducting material may be an adhesive having a heat conduction coefficient of 0.941 cal / cm · sec · ° C. or more. Further, particularly in the polygon scanner mirror motor having the polygon mirror 16, the zigzag land 22 is arranged on the GND pattern 21 of the motor control circuit section and the cream solder 23 is applied, so that the polygon mirror 16 is rotated by the high speed rotation. The wind hits the cream solder 23 and can enhance the heat dissipation effect of the metal base printed circuit board 1 itself. The heat conductive substance 2
0 and cream solder 23 are applied before mounting the motor driving IC 10 and fixed simultaneously with the resistor 11 and the capacitor 12 by cream solder.

As described above, according to the present embodiment, the motor driving IC 10 formed of the resin-molded flat package mounted on the metal base printed board 1 is used for driving the motor to generate heat generated when the motor is started. The thermal conductivity coefficient of 0.941, which is approximately twice that of aluminum, is provided on the metal base printed board 1 through the heat conductive material 20 applied in the gap between the IC 10 and the metal base printed board 1.
The heat radiation effect can be enhanced by directly radiating heat to the copper foil 24 having a cal / cm · sec · ° C.

Further, the heat conductive material is made to have a heat conductivity coefficient of 0.9.
By using an adhesive of 41 cal / cm · sec · ° C or higher, it is possible to conduct heat equal to or higher than that of copper foil, so that the heat generated by the motor drive IC when the motor is started can be efficiently transferred to the copper foil. By conducting and radiating heat, the heat radiation effect can be further enhanced.

In particular, in a polygon scanner mirror motor having a polygon mirror 16, staggered lands 22 are arranged on a GND pattern 21 of a motor control circuit section and cream solder 23 is applied to the polygon mirror to rotate at a high speed. The wind generated by the rotation of 16 hits the cream solder 23, and the heat dissipation effect of the metal base printed circuit board 1 itself can be enhanced, and the heat dissipation effect of the motor driving IC 10 can be further enhanced. Also, motor drive IC
Before mounting 10, the heat conductive material 20 and the cream solder 23 are applied, and the resistor 11 and the capacitor 12 and the motor driving IC 10 are fixed at the same time by the cream solder, so that the equipment for mounting the heat sink is provided. No longer needed
It is possible to obtain a polygon scanner motor which has a simple motor structure and realizes high quality and low cost.

[0018]

As described above, in the brushless motor according to the present invention, the heat generated when the motor of the motor driving IC is started is transferred to the metal base printed circuit board 1 through the heat conductive material.
In the polygon scanner mirror motor having a polygon mirror, which radiates heat directly to the copper foil 23, a staggered land is arranged in the GND pattern of the control circuit portion provided on the metal base printed board, and the land is soldered. By applying (1) to radiate heat to the copper foil of the metal base printed circuit board,
The heat dissipation effect can be enhanced.

(2) Since the metal base printed circuit board itself radiates heat, the heat radiation effect can be further improved and the life of the bearing can be extended.

(3) The heat dissipating plate made of a separate piece is not required and the structure can be simplified. (4) With the simplification of the above configuration, it is possible to reduce costs such as reduction of man-hours. That is, an excellent brushless motor can be realized.

[Brief description of drawings]

FIG. 1A is a plan view of a brushless motor according to an embodiment of the present invention. FIG. 1B is a sectional view of a brushless motor according to an embodiment of the present invention.

FIG. 2 is a detailed view of an IC section according to an embodiment of the present invention.

FIG. 3A is a plan view of a conventional brushless motor. (B) Cross-sectional view of a conventional brushless motor

[Explanation of symbols]

1 Metal base printed circuit board 2a Bearing holder 2b sleeve 3 rotation axes 4 rotor boss 5 rotor frame 6 rotor magnet 7 Stator coil 8 Stator core 9 Hall element 10 Motor drive IC 11 resistance 12 capacitors 13 Bearings or sintered oil-impregnated bearings 14 C type retaining ring 15 Heat sink 16 polygon mirror 17 Mirror holding spring 18 C type retaining ring 19 retaining 20 Thermally conductive substance 21 GND pattern of control circuit 22 Staggered land 23 Cream Handa 24 copper foil

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-207718 (JP, A) JP-A-3-285347 (JP, A) Actually open 6-5376 (JP, U) Actually open 4- 90572 (JP, U) Actual development Sho 62-64163 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 29/00 H02K 21/00 H02K 9/22

Claims (2)

(57) [Claims] 1. A rotary shaft, a rotor boss fastened and fixed to an outer periphery of the rotary shaft, and a rotor boss fixed to an upper portion of the rotor boss.
A polygon mirror and a roller fixed to the bottom of the rotor boss.
Rotor frame and rotor fixed to this rotor frame
A rotor assembly and a magnet, the rotor assembly
And a rotor assembly for generating a driving force between the rotor magnet and the rotor magnet. The stator assembly is for driving a motor having a resin-molded flat package structure.
C and a polygon scanner mirror motor having a metal base printed circuit board on which the driving IC is mounted,
A heat conductive material is interposed in a gap between the motor driving IC and the metal base printed board, and a copper foil is provided on a portion of the metal base printed board to which the heat conductive material is applied .
Moreover, the staggered land is formed in the GND pattern of the motor drive circuit.
And apply cream solder to the land.
The wind generated by the rotation of the gon mirror applied to the land.
Poly characterized by being configured to strike the solder over arm
Gon scanner mirror motor. 2. The IC has a metal base print made of a heat conductive material.
It is mounted after being applied to the board and fixed with cream solder.
The polygon scanner mirror motor according to claim 1,