JPH0740780B2 - Brushless motor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless electric motor used as a blower fan drive source for a home air conditioner or the like.

2. Description of the Related Art In recent years, in air conditioners such as air conditioners, it is becoming mainstream to control the capacity of a compressor. Correspondingly, it is also required to adjust the amount of air blown to the heat exchanger in a wide variety of stages. In place of the induction motor as a fan drive source that has been used to meet these demands, A method of operating a brushless motor, which is easy to adjust, with a DC power source is being adopted. There is also a strong demand for this type of electric motor to be light, thin and short.

As a method of driving this brushless electric motor, two methods have been conventionally considered and adopted. The first conventional method is
This is a method in which the motor section A and the drive section circuit section B are separately configured and the lead wire group C is connected between the sections by adopting the configuration shown in the block diagram of FIG.

As a second method, as shown in FIG. 16, the motor section A and the drive circuit section B are integrally formed by resin molding. Examples thereof include the methods described in Japanese Utility Model Laid-Open No. 57-183053, Japanese Utility Model Laid-Open No. 55-141283, Japanese Patent Laid-Open No. 55-104594, and the like.

The present invention relates to this second method, and a conventional example of the second method will be described below with reference to the drawings.

FIG. 17 is a vertical sectional view of a brushless electric motor described in Japanese Utility Model Laid-Open No. 57-183053.

In FIG. 17, a winding 2 is wound around a yoke portion of an iron core 1 and an outer shell is formed by a resin mold 3. And bearing
The shaft 6 is supported by 4, 5 and the permanent magnet rotor 7
Is configured.

On the other hand, the control circuit 8 and the integrated circuit 9 forming the control circuit
Is fixed to the surface of the printed circuit board 10 on the side opposite to the iron core, and is embedded in the end of the winding in the resin mold 3.

The position sensor 12 is fixed to the surface of the printed board 10 on the iron core side. Power is supplied to the control circuit 8 by the lead wire 13, and the lead wire 13 is supported by the resin mold 3 by the output bush 14. Cooling fins 11 are formed on a part of the resin mold 3.

FIG. 18 is a cross-sectional view of (a) front and (b) side of a brushless motor disclosed in Japanese Utility Model Laid-Open No. 55-141283.

In FIG. 18, a winding is wound around the yoke portion of the stator core 1, the core is fixed to the frame D, and the permanent magnet rotor 7 is supported by the shaft 6 and the bearings 4 and 5 fixed to the frame. Has been done.

On the other hand, the printed circuit board 10 on which the control circuit component including the sensor is mounted is formed in a space existing between the magnetic poles, and a cutout is provided in a portion where the winding interferes.

Problems to be Solved by the Invention In the conventional configuration as described above, the following can be considered.

First, the problems with respect to the configuration of Japanese Utility Model Laid-Open No. 57-183053 will be described below.

1). Since components are mounted on both sides of the printed circuit board, the printed circuit board requires double-sided boards having copper foils on both sides, resulting in high material cost.

2). As the axial length of the electric motor, the required cumulative length of the stator core from the end surface on the printed circuit board side is calculated as follows.

Iron core insulation thickness + coil end height + soldering height + insulation distance + printed circuit board thickness + control circuit component height + resin mold thickness, which is large relative to the entire axial length of the motor. As a result, it will not be able to meet the needs of light, thin, short, and small companies.

3). Due to the reason described in the second item, a large amount of the mold resin is required and the material cost becomes high.

4). Since the printed circuit board and control circuit parts are unevenly distributed in the resin mold, imbalance occurs in the resin flow during molding of the molding resin, making it difficult to control molding conditions and in terms of performance such as heat shock of the molded product. The variability also increases.

Next, in the example of FIG. 18 according to Japanese Utility Model Application Laid-Open No. 55-141283, 1). Since the notch is provided to allow the printed circuit board to sink into the winding height, the printed circuit board area (space) becomes extremely small as the number of magnetic poles increases, and mounting and printing of control circuit components Since the wiring pattern is limited, it is impossible to sink the printed board below the winding height (coil end).

2). When attempting to perform resin molding under the configuration of the above-mentioned item 1, the control circuit needs to consider mold pressure by lowering the mounting position as much as possible or reinforcing it with a fixing base or the like. is there.

Means for Solving Problems The present invention employs the following means in order to solve the problems of the conventional example. That is, winding is performed through the insulating layer for each tooth portion of the annular stator core having a plurality of slots,
Mounted on the same surface of the printed circuit board are the components for the drive circuit and the three position sensors with an electrical angle of 120 °, and the output bush for connecting to the lead wire for electricity supply and the IC or power of the drive circuit. At least one of the transistors is arranged on a substantially diameter line of the printed circuit board, and an integrally molded sensor fixing base for holding and fixing three position sensors is arranged so that the central position sensor is substantially orthogonal to the diameter line, Above IC
Alternatively, at least one of the power transistors is provided in either one of the sensors, and at least a part of the other drive circuit components is on the opposite side of the sensor fixing base with respect to the diameter line of the printed circuit board and the stator. It is arranged so that it is located between the teeth of the iron core, that is, in the space between the windings, and the surface of the printed circuit board on which the drive circuit components are mounted is placed facing the stator core end surface. Set up. At this time, the sensor fixing base is inserted into the insertion groove of the shroud provided in the tooth portion of the iron core, and the stator iron core, the winding, and the printed circuit board are integrally molded and solidified with the thermosetting resin to form the stator. The stator and the rotor thus obtained are rotatably supported by the bearing device, whereby the brushless motor of the present invention is obtained.

With the above configuration, it is possible to use a so-called single-sided board having a copper foil on only one side, and three sensors are inserted into the sensor fixing base at an electrical angle of 120 degrees and integrated. It can be made to a minimum size because it is configured into.

On the other hand, place the output bush and the IC or power transistor almost on the diameter line of the printed circuit board, place the sensor fixing base on one side of the diameter line of the printed circuit board, and place one power transistor or IC between the sensor and the sensor. , And the other parts are arranged on the side where the sensor fixing base is not provided, so that the parts can be dispersedly arranged on the printed circuit board.

In addition, since the sensor fixing base can be made small, its strength is also strengthened, and since the drive circuit components are also placed in the space between the windings, the printed circuit board can be placed up to the vicinity where the coil end contacts the printed circuit board. It is possible to place it closer to the stator core.

As a result, the amount of mold resin used can be reduced.
In addition, among the drive circuit components mounted on the printed circuit board, the power transistors and driver ICs, which have a relatively large volume, are arranged in a radial pattern, which can mitigate the uneven distribution of the components and affect the fluid pressure of the mold resin. A highly reliable electric motor can be obtained without receiving.

Examples Hereinafter, an example in which the present invention is applied to a three-phase full-wave energization type brushless motor will be described in detail with reference to the drawings.

FIG. 1 is an assembly state diagram of a stator winding of a brushless motor according to an embodiment of the present invention. In FIG. 1, a stator core 1 is formed by laminating iron plates, and a core insulation 2 is formed by integral molding with the core 1 or by inserting a molded product into the core. This iron core insulation will be described later in detail with reference to FIG. The winding 3 is wound around the tooth portion 1a of the iron core 1 provided with the iron core insulation 2. At this time, the shroud parts 2a, 2b of the core insulation 2
Prevents the winding from collapsing, and at the same time, a groove 2c for inserting the sensor fixing base 8 is provided on the inner diameter surface of the shroud portion 2a.

On the other hand, the printed circuit board 4 is formed in a substantially donut shape even though it has the winding hooking groove 4a and the winding end winding protrusion 4b on the outer periphery thereof, while the driver IC 5 and the electric supply lead wire 13 are The position sensor 7 using the Hall element is arranged on the diametrical line with the connected output bush 14 and has an electrical angle.
The sensor mounting base 8 is arranged so as to have a pitch of 120 degrees and a mechanical angle of 60 degrees, and is mounted on the printed circuit board 4. At this time, the sensor fixing base 8 is arranged so that its center position sensor is almost on a straight line orthogonal to the diameter line connecting the output bush 14 and the driver IC 5, and the power transistor array 6a is arranged between the sensors. The power transistor array 6b is arranged together with other components on the opposite side of the sensor fixing base with respect to the diameter line.
When this printed circuit board 4 is mounted on the stator core 1 whose winding is completed, it is mounted at a position where it does not come into contact with or interfere with the winding 3 and the shroud portions 2a and 2b.

The printed circuit board 4 holds the printed circuit board 4 in a fixed position in a mold at the time of resin molding, which will be described later, and is a hole for inserting a through bolt or a rivet at the time of assembling an electric motor after molding and has a mold pin to be molded. A hole 4c for inserting is provided. Further, a lead bush 14 for protecting the lead wire group 13 for supplying power from heat and pressure during resin molding is fixed to the lead wire group 13 on the printed circuit board 4. At this time, prevent the interference between the output bush 14 and the printed circuit board 4,
To determine the position of the output bush 14, the printed circuit board 4
A positioning groove 4d is provided in the core and a positioning hole 4e for positioning the core insulation is also provided.

The stator core 1 in which the winding is completed and the printed circuit board 4 on which the components are mounted as described above have a screwdriver between the shroud part and the adjacent shroud part as shown in the side view of the completed winding of FIG. The IC 5 and the power transistor arrays 6a and 6b are positioned and combined so that the axial ends of the shroud portions are brought into contact with the printed circuit board surface to complete the stator winding finished product 15.

At this time, the sensor fixing base 8 arranged on the printed board is inserted into the sensor fixing base insertion groove 2c provided in the shroud. FIG. 3 is a perspective view of this state, in which the winding end 3a is hooked in the winding hooking groove 4a of the printed board 4 and then the winding end winding protrusion is formed.
It is wound around 4b and fixed conductively with solder. It should be noted that FIG. 3 does not show the printed wiring on the printed circuit board surface, the drive circuit component lead holes and the like.

The stator winding finished product 15 is molded by resin molding to form a stator, and FIG. 4 is a sectional view showing a resin molded state. The finished stator winding product 15 is mounted in the cavity 16a of the lower mold 16, sealed by the upper mold 17, and the mold resin 19 is injected under pressure from the gate 18.

A plurality of pins 20 and 21 are projected on the upper mold 17, and the pin 20 secures a hole for inserting a fastening component such as a bolt or a rivet when assembling the motor. The pin 21 is a mold for resin molding. The printed board 4 is held by the fluid pressure of the resin 19 or the like to prevent the printed board 4 from being moved or bent.

For the same purpose as above, the pin 22 is also provided at the upper end of the mandrel 16b of the lower mold 16. Further, the pin 20 also has a modified stepped shape as shown in FIG. 5 for the same purpose, and the printed board 4 is pressed by the outer peripheral projection 20a during resin molding. The enlarged front view and the vertical cross section of the hole formed by the pin 20 are as shown in Fig. 6, and the portion formed by the outer peripheral chamfered portion 20b of the pin 20 is used as a seat when fastening with through bolts or rivets. To do.

The iron core insulation 2 may have a shape as shown in FIG. 7 as an example. This is obtained by integral molding with the stator core 1, and an inner shroud portion 2a and an outer shroud portion 2b are formed for each tooth portion 1a. A groove 2c for accommodating the sensor insertion portion 8a of the sensor fixing base 8 shown in FIG. 8 is provided on the inner diameter surface of the inner shroud portion 2a, and the thickness of both side portions 2d of this groove 2c is larger than that of other portions. It is thickly molded.

Further, the outer shroud portion 2b is provided with a plurality of protrusions 2e for positioning the printed circuit board 4. The sensor fixing base 8 is formed to be wider than the width of the sensor insertion portion 8a, and the centers of the two can be moved to adjust the phase shift due to the armature reaction, and the groove 8c into which the sensor lead 7a is inserted is As shown in FIG. 9, there is provided a smooth slope between the groove tip and the sensor lead insertion hole 8d so that the sensor lead can be inserted without forming.

Further, as shown in FIG. 10, it is possible to provide two sensor insertion grooves 8b next to each other in the sensor insertion portion 8a.
By disposing the individual grooves, it is possible to support both applications in which the rotation direction of the electric motor is forward or reverse.

Further, by disposing the sensor insertion groove 8b at one central position, it is possible to provide a motor capable of forward and reverse rotation with one unit.

FIG. 11 is a perspective view showing an assembled state of an inversion type brushless electric motor which is an embodiment of the present invention. FIG. 12 is a front view of the electric motor of FIG. 11, and FIG. 13 is A-0- of FIG. It is a sectional side view by the B line.

In FIG. 11, the permanent magnet rotor is inserted through the stator 23, the bearing devices 25 are mounted from both sides, and the fasteners 26 are fastened to complete the process.

Here, the permanent magnet rotor 24 is composed of a shaft 27, a rotor yoke 28 fixed to the shaft 27, and a permanent magnet piece 29 fixed to the outer circumference of the rotor yoke with an adhesive. A plurality of recesses are provided in the axial direction as a space for accumulating extra adhesive to facilitate the attachment of the permanent magnet pieces 29 by mounting. Further, one end of the permanent magnet piece 29 in the circumferential direction is always brought into contact with a convex portion provided on the outer circumference of the rotor yoke 28 so as to facilitate positioning by adhesion.

The end face of the stator 23 is formed with a recess 23a that abuts the bearing device 25. A part of this is formed so as to reach the outer diameter surface of the stator 23 radially, and a bearing with a flange as shown in FIG. The device 25a is also configured to be able to abut.

In FIG. 13, the thrust boss 30 is mounted on the end surface of the permanent magnet rotor 24 on the load shaft side. This is a permanent magnet rotor 24
Regulates the amount of movement to the load shaft side when the bearing receives a thrust force on the load shaft side, and abuts on a part of the bearing device 25 to prevent movement (thrust amount) beyond a specified amount.

Effects of the Invention With the configuration of the present invention as described above, the following effects can be obtained.

． Since the printed circuit board used can be a single-sided copper foil board, it can be obtained at low cost.

． The required axial length from the end face of the stator iron core is [the size of the larger of the core insulation thickness + coil end height and maximum height of drive circuit components + printed circuit board thickness + soldering height +
The thickness of the resin mold], and the coil end height can be kept lower than that of the conventional example. Therefore, the height can be reduced by the height of the drive circuit components and the insulation distance. Usually, the value that can be kept short is about 7 to 10 mm.

． As described in the previous section, the length in the axial direction can be shortened to reduce the thickness, so that the amount of mold resin used can be reduced and the material quality can be reduced.

． The sensor mounting base on the printed circuit board becomes smaller, the drive circuit parts can be distributed, and the flow of the mold resin during resin molding becomes more even, and the occurrence of defective products due to cracks after molding is complete. Can be suppressed.

Further, since the resin flow approaches uniform, stress applied to the printed circuit board, the drive circuit parts, or the built-in parts such as the position sensor can be reduced.

． Overall, it is possible to obtain a brushless electric motor that meets the needs of thin, lightweight, light, thin, short and small products.

[Brief description of drawings]

FIG. 1 is a perspective view of a stator winding assembly state, FIG. 2 is a side view of a completed stator winding, FIG. 3 is a perspective view of a completed stator winding, and FIG. 4 is a schematic sectional view showing a resin molding state. FIG. 5 is a partial perspective view of the upper die pin, FIG. 6 is a partial front view of the stator, FIG. 7 is a partial perspective view of the iron core insulating portion, FIG. 8 is a perspective view of the sensor fixing base, and FIG. FIG. 10 is a partial cross-sectional view of the drawing, FIG. 10 is a perspective view of another embodiment of the sensor fixing base, FIG. 11 is a perspective view showing an assembled state of an inversion type brushless electric motor according to the present invention, and FIG. 12 is a brushless according to FIG. Fig. 13 is a front view of the electric motor, Fig. 13 is a side sectional view taken along the line A-O-B in Fig. 12, Fig. 14 is a perspective view of an embodiment in which a bearing device with a flange portion is in contact, and Fig. 15 is a conventional example. FIG. 16 is a block diagram of the configuration of the first method, and FIG. 16 is a block diagram of the configuration of the second method of the conventional example.
FIG. 17 is a vertical sectional view of a brushless electric motor according to the second method of the conventional example, and FIG. 18 is a front sectional view (a) and a side sectional view of a brushless electric motor described in Japanese Utility Model Publication No. 55-141283. Is. 1 ... Stator core, 2 ... Core insulation, 3 ... Winding, 4 ...
… Printed circuit board, 5… Driver IC, 6a, 6b… Power transistor array, 7… Position sensor, 19… Mold resin, 23… Stator, 24… Permanent magnet rotor, 25…
… Bearing device.

Claims (1)

[Claims] 1. An annular stator core having a plurality of slots, windings formed on the teeth of the stator core via an insulating layer, drive circuit parts and an electrical angle of 120 °. And a printed circuit board on one side of which the three position sensors are mounted, and is connected to at least one of the IC or the power transistor among the drive circuit components mounted on the printed circuit board and the electric supply lead wire. And a fixing bush for holding and fixing the three position sensors are arranged so that the central position sensor is substantially orthogonal to the diameter line of the printed circuit board. , At least one of the IC or the power transistor is arranged in any one of the three sensors, and at least a part of the other drive circuit components is the sensor with respect to the diameter line of the printed circuit board. The printed circuit board is arranged so as to be located on the side opposite to the fixed base and in the space between the windings, and the windings are connected to the winding connection printed wiring provided on the printed board, A stator formed by integrally molding and solidifying the stator core, windings, and drive circuit with thermosetting resin having electric insulation; a permanent magnet rotor arranged inside or outside the stator; A brushless electric motor comprising a bearing device that rotatably holds a rotor on the stator.