JP4843303B2 - Brushless motor - Google Patents

Description

  The present invention relates to a brushless motor used as a main motor for simultaneously driving various mechanisms such as a copying machine and a laser beam printer, and in particular, a stator core (iron core) around which a stator coil is wound, a rotor attached with a ring magnet, and a rotor The present invention relates to a brushless motor having a hall element for detecting the position of the rotor and a speed detecting means for detecting the rotational speed of the rotor, and incorporating a drive / control circuit for rotating and controlling the rotor integrally with the motor. is there.

  In recent years, document products such as copiers and laser beam printers have been aimed at higher image quality, higher speed printing, and colorization in recent years, and in order to realize them simultaneously, so-called tandem systems are provided with a photosensitive drum for each color. There is a tendency. Although the conventional one-drum configuration is a two-drum and four-drum configuration, the size of the equipment cannot be denied, but the main motor that drives various mechanisms to reduce the size is reduced in thickness. There is a demand for smaller diameter, space saving, and higher output.

  And as a main motor, a brushless motor that incorporates a motor unit having a stator with a stator core (iron core) suitable for high output and a drive / control circuit for rotationally driving and controlling the motor is generally used. Therefore, it is required to reduce the thickness, diameter, space, and output of the entire motor including the circuit portion.

  On the other hand, in a brushless motor used as a so-called main motor that simultaneously drives various mechanisms such as a copying machine and a laser beam printer, a high output is required, so that a large current needs to flow through a stator coil (armature coil). However, when the drive current is increased, heat generation due to power loss in the power section of the drive / control circuit increases. Therefore, since it is necessary to attach a heat sink to the power section, this has been an obstacle to reducing the thickness, diameter, and space of the main motor.

  Therefore, as a solution to the above-described conventional problems in a brushless motor used as a so-called main motor for simultaneously driving various mechanisms such as a copying machine and a laser beam printer, an electronic component of a power unit is mounted on a mounting plate for mounting the brushless motor on a device. The structure which omits a heat sink by making these contact directly is proposed (for example, refer patent document 1).

FIG. 4 shows a conventional technique described in Patent Document 1 described above.
In FIG. 4, 41 is a circuit board. On the upper surface of the circuit board 41, a driving / control circuit for rotating and controlling a rotor such as the control integrated circuit 42 is mounted. A space 43 is provided between the control integrated circuit 42 and the upper surface of the circuit board 41, and an electronic chip component 44 is disposed in the space 43. Reference numeral 45 denotes a motor mounting plate, which has a width that substantially covers the entire top surface of the motor, is disposed close to the circuit board 41, and has a bottom surface that contacts the top surface of the control integrated circuit 42 to function as a heat sink. Plays.

As described above, the control integrated circuit 42 and the electronic chip component 44 are disposed on the upper surface of the circuit board 41, and the speed detection pattern (speed detection planar coil) 46 and the circuit are printed on the lower surface of the circuit board 41. Outer leads 47 of the control integrated circuit 42 are formed so as to protrude to the lower surface side of the circuit board 41.
Japanese Utility Model Publication No. 7-9078 (page 5-7, FIG. 1)

  However, in the configuration according to the prior art, since the heat dissipation effect varies unless the control integrated circuit 42 is securely brought into contact with the motor mounting plate, it is necessary to attach the control integrated circuit 42 from the circuit board 41 at a uniform interval. Yes. Therefore, there is a problem that workability is extremely poor. Further, since the chip component 44 is mounted between the control integrated circuit 42 and the circuit board 41 in order to reduce the outer diameter of the motor (circuit board), it is also interposed between the control integrated circuit 42 and the chip component 44. It becomes necessary to provide the space portion 43, and the thickness is hindered.

  The present invention solves such a conventional problem, and suppresses heat generation of a drive / control integrated circuit that drives a brushless motor in a limited space, while reducing the thickness, reducing the diameter, saving space, and It is an object of the present invention to provide a brushless motor in which a drive / control circuit for achieving high output is integrated with a motor.

  In order to solve the above-described problems, the present invention provides a copper foil on a circuit board facing the rotor magnet end face of a brushless motor, and drives a brushless motor mounted on a surface opposite to the copper foil. The pattern to which the lead of the power part of the drive / control circuit to be connected is connected by a copper foil and a through hole.

  According to the first aspect of the present invention, since the copper foil area to which the lead of the power part of the drive / control circuit for driving the brushless motor is connected can be widened, parts are added for heat dissipation. Since heat generation can be suppressed without any problem, downsizing becomes easy.

  According to the second aspect of the present invention, since the comb-shaped portion of the copper foil is cooled by the air flow generated by the rotation of the rotor, the heat generated in the power portion of the drive / control circuit conducted to the comb-shaped portion is more effective. Heat is effectively dissipated.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1A to FIG. 3 show a brushless motor of (Embodiment 1) of the present invention.

  In FIG. 1A, reference numeral 1 denotes a stator coil, which is wound around each salient pole of the stator core 2. Reference numeral 3 denotes a rotor yoke made of a magnetic material. A rotor magnet 4 attached to the inner periphery of the rotor yoke 3 and a shaft 5 fixed at the center form a rotor 6. A bearing 7 supports the shaft 5 of the rotor 6. Reference numeral 8 denotes a housing having a cylindrical portion 8a and a flange portion 8b. The bearing 7 is held on the inner periphery of the cylindrical portion 8a of the housing 8, and the stator core 2 is fixed to the outer periphery of the cylindrical portion 8a of the housing 8.

  In the present embodiment, a mounting plate 10 made of a magnetic material is provided on the flange portion 8b of the housing 8, and the mounting plate 10 is attached to a device on which the motor is mounted. A plurality of drive magnetizations are applied to the inner peripheral surface of the rotor magnet 4 in the radial direction. An FG magnet portion 4 a is formed on the end face of the open end of the rotor magnet 4. This FG magnet portion 4a has a plurality of poles more than the drive magnetization in order to increase the resolution of speed detection in the circumferential direction in which a plurality of N and S magnetic poles are alternately arranged in a direction orthogonal to the drive magnetization on the inner peripheral surface of the rotor magnet 4. Is magnetized.

  An FG pattern (speed detection pattern) 21 and a cancel pattern 22 are formed on one surface 11 a of the circuit board 11 attached to the flange portion 8 b of the housing 8 so as to face the FG magnet portion 4 a on the end surface of the rotor magnet 4. Yes. As shown in FIG. 2 (a), the FG pattern (speed detection pattern) 21 has the power generating element 21a equal to the number of magnetic poles of the FG magnet portion 4a opposed to the FG magnet portion 4a on the end face of the rotor magnet 4. The power generation line elements 21a are connected in series and formed in an annular shape.

  The cancel pattern 22 is disposed inside the FG pattern 21 so as to surround the FG pattern 21, and the noise component superimposed on the speed detection signal due to noise generated from the stator coil 1 and the noise generated in the cancel pattern 22 are in reverse phase. The FG pattern 21 is formed so as to be connected in series.

  In addition to the FG pattern (speed detection pattern) 21 and the cancel pattern 22, a copper foil 23 shown in FIG. 2B is formed on one surface 11 a of the circuit board 11. In the present embodiment, the copper foil 23 has three independent patterns 23a, 23b, and 23c, and is electrically insulated from each other. Further, in the independent patterns 23a, 23b, and 23c of the copper foil 23, a comb-like portion 23d formed in a nested structure is formed between the line elements 21a of the FG pattern (speed detection pattern) 21, and FIG. As shown in FIG. 3C, the FG pattern (speed detection pattern) 21 is disposed so as to be substantially annularly surrounded from the outside in the radial direction.

  Further, a plurality of through holes 23e are formed in the independent patterns 23a, 23b, and 23c of the copper foil 23, respectively.

  On the other hand, on the other side 11b of the circuit board 11, as shown in FIG. 3, the driving / control integrated circuit of the driving / control circuit section, the Hall elements 12U, 12V, 12W and the small resistor 13 are surface mounted by soldering. Has been. The integrated circuit includes a pre-drive / control integrated circuit 14, a first power MOS array 15U for turning on / off the current to the U-phase stator coil, and a second for turning on / off the current to the V-phase stator coil. The power MOS array 15V is configured to be distributed in a plurality of packages of the third power MOS array 15W for turning on / off the energization to the W-phase stator coil. The wiring patterns 31U, 31V, and 31W are connected to the leads of the first power MOS array 15U, the second power MOS array 15V, and the third power MOS array 15W, respectively. The wiring patterns 31U, 31V, and 31W are configured to have a large area so that heat generated in the power MOS array is conducted and dissipated. A part of the wiring patterns 31U, 31V, and 31W is disposed so as to overlap the independent patterns 23a, 23b, and 23c of the copper foil 23 formed on the one surface 11a of the circuit board 11 on the back and front sides of the circuit board 11, respectively. These are configured to be thermally coupled to each other through the through holes 23e. The above configuration will be described in more detail with reference to FIG. 1A, which is a view taken along the line X-X ′ in FIG. 3, and FIG. 1B, which is a detailed view of a P portion in FIG. A part of the wiring pattern 31V connected to the lead of the second power MOS array 15V mounted on the one side 11b side of the circuit board 11 is independent of three copper foils 23 formed on the other side 11a side. One of the patterns 23a and the circuit board 11 are arranged so as to overlap each other and are thermally coupled by a plurality of through holes 23e.

  With the above configuration, the copper foil area to which the power lead of the drive / control circuit that drives the brushless motor is connected can be increased, so heat generation can be suppressed without adding components for heat dissipation. Becomes easy.

Further, as shown in FIG. 1B and FIG. 2C, which are detailed views of the P portion of FIGS. 1A and 1A, the copper foil 23 formed on the one surface 11a side of the circuit board. Since the comb-like portion 23d formed on the one of the three independent patterns 23a is disposed so as to face the FG magnet portion 4a on the end surface of the rotor magnet 4, air generated by the rotation of the rotor 6 is provided. Since the comb-like portion 23d of the copper foil 23a is cooled by the flow, the heat generation of the second power MOS array 15V which is the power portion of the drive / control circuit conducted to the comb-like portion 23d is more effectively dissipated. Has the effect of being

  Since the first power MOS array 15U and the third power MOS array 15W have the same configuration as described above, it is obvious that the above-described effects can be obtained.

  In the present embodiment, the copper foil 23 is formed so as to surround the FG pattern (speed detection pattern) 21 in a substantially annular shape from the outside in the radial direction so that the heat radiation effect by the air flow generated by the rotation of the rotor 6 can be most effectively exhibited. The independent patterns 23a, 23b and 23c of the copper foil 23 are provided so as to surround the FG pattern (speed detection pattern) 21 in an annular shape from the inside in the radial direction. Even if an effect is acquired. In this case, the outer dimensions of the circuit board 11 can be further reduced. Further, by arranging the cancel pattern 22 outside the FG pattern 21, the comb-like portions 23 d are formed on the independent patterns 23 a, 23 b and 23 c of the copper foil 23 between the line elements 21 a of the FG pattern (speed detection pattern) 21. Can be formed in a nested structure from the inside in the radial direction.

  In addition, according to the above configuration, the FG pattern 21 and the cancel pattern 22 are provided on the other side 11a opposite to the one side 11b of the circuit board 11 on which the driving / control integrated circuit and electronic components are arranged. Further, a copper foil 23 is printed.

  All the soldering lands of the circuit board 11 are arranged on the surface 11 b opposite to the FG pattern 21.

  As a result, it is possible to solder the driving / control integrated circuit and electronic components corresponding to the surface mounting at the same time, and the man-hour can be greatly reduced. Further, since there is no lead or terminal portion protruding on the stator coil 1 side, there is no need to increase the distance between the stator coil 1 and the circuit board 11, and the height of the component mounting surface can be reduced, so that the overall height of the motor can be reduced. .

  As described above, it is possible to provide an operation and effect that it is possible to provide a drive / control circuit-integrated brushless motor that is excellent in diameter reduction, space saving, and suitable for high output.

  Further, by providing the hole 8c in the flange portion 8b of the housing 8, this flange portion 8b can be used as an attachment portion to a device on which the motor is mounted. With this configuration, there is no need for a separate mounting member, and the number of motor components can be reduced. Therefore, a brushless motor can be provided in which the motor height can be further reduced and the number of assembly steps can be reduced.

  The brushless motor of the present invention is useful as a main motor for simultaneously driving various mechanisms such as a copying machine and a laser beam printer.

(A) Cross-sectional view of the first embodiment of the present invention, (b) Enlarged cross-sectional view of the main part of the first embodiment of the present invention. (A) FG pattern (speed detection pattern) diagram of Embodiment 1 of the present invention, (b) A diagram showing a copper foil of the same embodiment, (c) FG pattern (speed detection pattern) diagram of the same embodiment And figure showing copper foil Plan view of the same embodiment Cross-sectional view of a conventional brushless motor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stator coil 2 Stator core 3 Rotor yoke 4 Rotor magnet 4a FG magnet part 5 Shaft 6 Rotor 7 Bearing 8 Housing 8a Cylindrical part 8b Flange part 8c Screw hole 10, 45 Mounting plate 11, 41 Circuit board 11a One side of circuit board 11b Circuit board 11 Other side of 12U, 12V, 12W Hall element 13 Small resistor 14 Pre-drive / control integrated circuit 15U, 15V, 15W First to third power MOS arrays 21, 46 FG pattern (speed detection pattern)
21a Power generation line element of speed detection FG pattern 21 Cancel pattern 23 Copper foil 23a, 23b, 23c Independent pattern of copper foil 23 23d Comb portion 23e Through hole 31U, 31V, 31W Wiring pattern 42 Control integrated circuit 43 Space Part 44 Electronic chip part 47 Outer lead

Claims (2)

A stator core around which a stator coil is wound, and a cup-shaped rotor yoke in which a ring-shaped magnet arranged on the inner periphery and subjected to a plurality of drive magnetizations in the circumferential direction is attached to the inner periphery. A rotor composed of a shaft fixed to the center of the rotor yoke, a bearing that rotatably supports the shaft, a housing that holds the bearing on its inner peripheral side, and holds the stator core on its outer peripheral side, Hall element for detecting the position of the rotor magnet in the rotational direction, speed detecting means for detecting the rotational speed of the rotor, integrated drive / control circuit for controlling and driving the rotor fixed to the housing, and surface mounting A circuit board on which a drive / control circuit composed of a corresponding electronic component is mounted, and the speed detecting means is an open end of the rotor A plurality of magnetized portions provided in a circumferential direction on the magnet end surface of the magnet, and the magnetization disposed at a position corresponding to the magnetized portion and facing the magnet end surface of the rotor on the circuit board The drive / control integrated circuit is connected to a pre-drive / control integrated circuit and a stator coil. The drive / control integrated circuit and the surface mountable electronic components are all formed with a speed detection pattern of a circuit board. A surface of the circuit board is mounted by soldering on the opposite side, and a copper foil is disposed separately from the speed detection pattern on the side on which the speed detection pattern is formed on the circuit board. Brushless motor each lead S array is linked by a through hole of the copper foil wiring pattern are connected. The brushless motor according to claim 1, wherein the copper foil has a comb-like portion formed in a nested structure between the line elements of the speed detection pattern.

Images