JP2987181B2 - Brushless motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a brushless motor.

[Related Art] Conventionally, a rotating body provided with a field magnet is rotatably supported by a cylindrical bearing, and a plurality of armature coils are provided on an outer peripheral portion of the bearing. A brushless motor provided with a plurality of Hall elements for detecting a magnetic pole is known. In assembling such a motor, each armature coil and the Hall element are fixed to a predetermined position on the outer periphery of the bearing, and then these are electrically connected using a lead wire or the like.

[Problems to be Solved by the Invention] However, after the armature coil or the like is fixed to the bearing, it is necessary to perform a connection work on the outer peripheral surface of the bearing,
There is a problem that the productivity of the motor cannot be improved due to the complicated operation.

Further, it is not easy to fix a plurality of armature coils at predetermined positions on the outer peripheral surface of a bearing having no mark. Therefore, since the mounting position of each armature coil is inaccurate, the controllability of the motor may be impaired, and there has been a problem in quality control.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a brushless motor that can easily and accurately mount an armature coil or the like on a peripheral surface of a bearing and can stably rotate a rotating body. Is to provide.

[Means and Actions for Solving the Problems] To solve the above problems, the present invention provides a rotating body including a field magnet and rotatable around one axis,
The rotating body is rotatably supported by being formed in a cylindrical shape by an insulating ceramic material, and a bearing in which a wiring circuit is formed in advance on an outer peripheral portion thereof is mounted on a wiring circuit of the bearing. And an armature coil for driving the rotating body.

According to this configuration, since a wiring circuit is formed in advance on the outer peripheral portion of the bearing, it is not necessary to provide a new retrofitting circuit after the armature coil is attached to the wiring circuit, and the motor assembly process Is greatly simplified.

Further, using a wiring circuit formed in advance on the outer peripheral portion of the bearing as a guide, the armature coil is accurately attached to a predetermined position on the outer peripheral portion of the bearing. Accordingly, the armature coils are arranged at equal angular intervals as designed, and the field magnet of the rotating body and the armature coil can mutually exert a magnetic action periodically. Therefore, the rotating body is smoothly rotated without causing rotation unevenness or the like.

Further, since the bearing is formed of an insulating ceramic material, even if a wiring circuit is formed directly on the surface of the bearing, no trouble such as electric leakage occurs.

It is preferable that the bearing is provided with a gas introduction hole for introducing a pressurized gas into a clearance between the bearing and the rotating body.

According to this configuration, the pressurized gas is introduced from the gas introduction hole provided in the bearing to the clearance between the bearing and the rotating body. A static pressure is generated in the clearance based on the pressurized gas, and the rotating body is supported by the bearing in a non-contact state.

The insulating ceramic material is preferably at least one selected from alumina, zirconia, silicon nitride, sialon, and the like.

This is because these ceramic materials not only have excellent electrical insulation properties, but also have excellent wear resistance and mechanical strength, and are suitable as bearing constituent materials. It is preferable that the insulating property of the ceramic material is 10 ¹⁰ Ωcm or more in volume resistivity.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 to 3, the drive unit of the brushless motor is composed of a cylindrical bearing 1 made of an alumina sintered material and a substantially cylindrical rotating body 2.
A rotating body 2 is inserted into the bearing 1, and the rotating body 2 is rotatably supported on the inner peripheral surface of the bearing 1 with a radial clearance C of 10 to 50 μm.

As shown in FIGS. 2 to 4, each position at a position separated by a predetermined distance from both ends of the bearing 1 and further dividing the cross section of the bearing 1 at that position into three or more equal parts (in this embodiment, four equal parts) Are provided with a total of six or more (eight in this embodiment) gas introduction holes 3 respectively. Each gas introduction hole 3 connects the outer peripheral portion and the inner peripheral portion of the bearing 1 and is connected to an air compressor (not shown). Then, pressurized air from the air compressor is supplied between the bearing 1 and the rotating body 2 through the respective gas introduction holes 3,
Due to the static pressure based on the pressurized air, the rotating body 2
Is radially supported without contact.

As shown in FIGS. 2 and 3, the rotating body 2 includes a shaft 6,
It comprises a support plate 7, a cylindrical cover 8 and a field magnet 9. Here, a pair of support plates 7 are fixed on the shaft 6 at a predetermined interval, and a cylindrical cover 8 made of an alumina sintered material is interposed between the support plates 7.
Is held. Then, the shaft 6 and the cylindrical cover 8
Between them, four field magnets 9 are held. The field magnets 9 are arranged alternately in an annular shape around the shaft 6 so that adjacent magnetic poles have different polarities.

On the other hand, as shown in FIGS. 1 to 3, a plurality of armature coils 4 and Hall elements 5 (each 3
Pieces) are attached. Each Hall element 5 is an IC that detects the magnetic pole of the field magnet 9 in the rotating body 2 facing each other and emits a predetermined signal in accordance with a change in the magnetic pole. ,
It has a signal terminal.

Here, as shown in FIG. 4, on the outer peripheral surface of the bearing 1, a connecting portion for connecting the armature coils 4 and the Hall elements 5 to each other, and each armature coil 4 and the Hall elements 5 are connected to a motor. A wiring circuit including a large number of soldering portions for connecting to an external device such as a power supply provided outside is formed in advance.

That is, on the outer peripheral surface of the bearing 1, as a wiring circuit for the armature coil, there are provided three soldering portions 11a to which one ends of the windings of the armature coils 4 are respectively soldered. Coupling wiring 11 for connecting parts 11a to each other
And the other ends of the windings of each armature coil 4 are soldered respectively, and three independent external soldering portions 12 for connecting an external power supply and each armature coil 4 are formed. I have.

Further, on the outer peripheral surface of the bearing 1, a power supply wiring 13, a ground wiring 14, and three signal wirings 15 are formed as wiring circuits for the Hall element.

The power supply wiring 13 includes three soldering portions 13a to which power supply connection terminals of the respective Hall elements 5 are soldered, and an external soldering portion 13b for connecting an external power supply. It is provided with a connecting portion for connecting to each other. Similarly, the ground wiring 14 has three soldered portions to which the ground terminals of each Hall element 5 are soldered.
14a and the external soldering part 1 for connecting the external ground wire
4b, and a connection portion for connecting these 14a and 14b to each other. Each signal wiring 15 has a soldering portion 15a to which a signal terminal of the Hall element 5 is soldered and an external soldering portion for connecting an external control device (not shown).
15b, and a connecting portion for connecting these 15a and 15b to each other. Note that the external control device is provided with each Hall element 5.
Is a device that controls the supply of electric power to each armature coil 4 based on the magnetic detection signal from

The wiring circuits 11 to 15 are formed by performing screen printing with a conductive paste while rotating the bearing 1. The conductive paste is obtained by mixing a thermosetting resin and a dispersion solvent with copper particles, and the viscosity of the paste is adjusted mainly by adjusting the amount of the dispersion solvent. Screen printing on the outer peripheral surface of the bearing 1 is performed in the following procedure.

(1) Using a conductive paste with a viscosity of 300 to 1000 poise, print and form the connection part except the soldered part of the wiring circuit, and then heat the printed surface at 200 ° C for 10 minutes to print the printed surface. The above paste is cured to form a connection portion having a thickness of 30 to 50 μm.

(2) Using a conductive paste having a viscosity of 1,000 to 2,000 poises, print and form the soldered portion of the wiring circuit, and then heat the printed surface at 200 ° C. for 5 minutes to remove the paste on the printed surface. It is cured to form a soldered portion having a thickness of 50 to 100 μm.

(3) The solution of the thermosetting resin used for the conductive paste is applied to the entire outer peripheral surface of the bearing 1, and the applied surface is heated at 200 ° C. for 5 minutes to cure the resin. A film having a thickness of 50 to 100 μm is formed on the outer peripheral surface. The coating has a heat resistance of about 150 to 200 ° C.

Now, when assembling the drive section of the brushless motor, each armature coil 4 and Hall element 5 are
Soldering portions 11a, 12, 13a, 1 formed in advance on the outer peripheral surface of
4a, 15a are arranged at the positions determined as a guide, and each end of the winding of each armature coil 4,
In addition, the power supply connection terminal, the ground terminal, and the signal terminal of each Hall element 5 are soldered. Thereby, each armature coil 4 and the Hall element 5 are fixed on the outer peripheral surface of the bearing 1 and are connected to each other.
At this time, the coating on the surface of each soldering portion is decomposed and removed by heat at the time of soldering.

Subsequently, the external soldering portions 12, 13 on the outer peripheral surface of the bearing 1
Lead wires such as an external power supply and an external control device are soldered to b, 14b, and 15b, respectively. Thereafter, the brushless motor is completed by mounting the bearing 1 and the rotating body 2 together with a well-known thrust bearing means such as a magnetic bearing in a casing of the motor.

In this brushless motor, the rotating body 2 is radially supported in a non-contact manner with the inner peripheral surface of the bearing 1 by the pressurized air introduced from each gas introduction hole 3 as described above. In this state, based on the magnetic pole detection signal from each Hall element 5, the external control device starts energization control to each armature coil 4. With this energization control, each armature coil 4 sequentially forms a magnetic field, and the rotating body 2 rotates based on the magnetic interaction between these magnetic fields and the magnetic fields formed by the field magnets 9 of the rotating body 2. Is done.

As described above, according to the present embodiment, the motor drive unit can be easily assembled by soldering each armature coil 4 and the Hall element 5 on a wiring circuit formed in advance on the outer peripheral portion of the bearing 1. Can be. Therefore, the productivity of the motor can be improved more than before.

Further, the armature coils 4 and the Hall elements 5 can be accurately arranged at predetermined positions using the wiring circuit on the bearing 1 as a guide. Therefore, each armature coil 4 and the Hall element 5 are arranged at equal angular intervals as designed on the outer peripheral surface of the bearing 1, and each armature coil 4 and the rotating body are controlled based on energization control of each armature coil 4. The two field magnets 9 periodically exert a magnetic effect on each other. Therefore, the rotating body 2 can rotate stably without causing rotation unevenness or the like.

Note that the present invention is not limited to the above embodiment,
You may implement as follows. (A) In the above embodiment, the screen printing on the outer peripheral surface of the bearing 1 is performed in two steps by dividing the screen into the connection part and the soldering part of the wiring circuit. The connection part and the solder part are formed at the same time.

(B) After the screen printing of the wiring circuit on the outer peripheral surface of the bearing 1, a guide line that clearly indicates the mounting position of each armature coil 4 and Hall element 5 is printed.

[Effects of the Invention] As described above in detail, according to the present invention, the armature coil and the like can be easily and accurately attached to the peripheral surface of the bearing, and the rotating body can be stably rotated. It has the effect.

[Brief description of the drawings]

1 to 4 show an embodiment of the present invention.
FIG. 2 is an exploded perspective view of the motor drive unit, FIG. 2 is a sectional view of the same, FIG. 3 is a sectional view taken along line AA of FIG. 2, and FIG. 1 ... bearing, 2 ... rotating body, 3 ... gas introduction hole, 4 ...
... armature coil, 9 ... field magnet, 11 ... coupling wiring, 12 ... external soldering part, 13 ... power supply wiring, 14 ... ground wiring, 15 ... signal wiring (wiring by 11 to 15 above) Circuit is formed), C ... clearance.

Claims (3)

(57) [Claims] 1. A rotating body (2) having a field magnet (9) and rotatable around one axis, and a rotating body (2) formed of an insulating ceramic material in a cylindrical shape and rotating the rotating body (2). A bearing (1) having a wiring circuit (11 to 15) formed in advance on the outer periphery thereof and a wiring circuit (11 to 15) on the bearing (1) are attached to the outer periphery thereof. Armature coil (4) for driving body (2)
A brushless motor, comprising: 2. A gas introduction hole (3) for introducing a pressurized gas into a clearance (C) between the bearing (1) and the rotating body (2). The brushless motor according to claim 1. 3. The method according to claim 1, wherein the insulating ceramic material is at least one selected from alumina, zirconia, silicon nitride, and sialon.
Or the brushless motor according to 2.