JPH0343831Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a brushless motor with a radial gap type core.

Before entering into a description of the present invention, an example of a conventional radial gap type brushless motor with a core will be explained with reference to FIGS. 1 and 2. In FIGS. 1 and 2, reference numeral 1 denotes a cylindrical permanent magnet rotor, which has four pairs of shaft poles in the circumferential direction, ie, a total of eight magnetic poles. This rotor 1 is fixed to the inner peripheral surface of a substantially dish-shaped yoke 2. A boss 3 is caulked and fixed to the center of the inner bottom surface of the yoke 2, and a rotating shaft 4 is attached to the boss 3 with a screw 5. The rotating shaft 4 is rotatably supported by a pair of upper and lower ball bearings 7, 7 fitted to the inner peripheral portion of the bearing holder 6. In FIG. 1, a sliding seat plate 8 is interposed between the inner circumferential ring of the upper ball bearing 7 and the boss 3. As shown in FIG. A center hole 9a of the stator core 9 is provided at the center outer periphery of the bearing holder 6.
is inserted with a light press-fit. A plurality of convex poles 9a facing the magnetic poles of the rotor 1 are formed on the outer periphery of the stator core 9, and a drive coil 10 having a two-phase or three-phase configuration is wound around each convex pole 9b. A coil end (not shown) of the coil 10 is connected to a circuit board 11, which will be described later. circuit board 11
is a well-known printed circuit board with printed wiring on one or both sides, and the circuit board 11 is placed on the flange 6a formed by extending from the lower edge of the bearing holder 6, and is placed on the inner hole. It is attached by screws 13 to the lower surface of the yoke plate 12 which is caulked and fixed by the caulking portion 6b. A portion of the circuit board 11 extends from the outer periphery of the yoke plate 12, and the drive coil 1 is attached to this extended portion 11a.
Circuit components 18 constituting a drive circuit and/or a speed control circuit for exciting each phase of 0 are connected to a predetermined printed pattern. The drive circuit or speed control circuit detects the magnetic poles of the rotor 1 using a Hall element or the like, and excites each phase of the drive coil 10 based on this output signal. Note that reference numerals 14 and 14 are screws for fixing the stator core 9, and by screwing the screws 14 through the yoke plate 12 and the spacer 15 into the screw holes protruding from the flange 6a of the bearing holder 6. , the stator core 9 is fixed. Symbol G is a detector for detecting the rotational speed of the rotor 1, and the detector G is attached to the inner bottom surface of the yoke 2 of the rotor 1 and is magnetized with multiple poles.
It is constructed by opposing power generation coils made of printed coils fixed to the core 9 and disposed on the upper surface of the generator yoke 17. Detector G
A voltage signal or a frequency signal corresponding to the rotation of the rotor 1 output from the generator coil is applied to the control circuit to form a speed control loop.

According to the conventional brushless motor configured in this way, the drive circuit and/or the speed control circuit are arranged on the circuit board that extends beyond the outer diameter of the rotor. The area is large, the space factor is poor, standardization and automation of assembly is difficult, and different circuit boards must be made for each order of the motor customer.

The purpose of the present invention is to enable the drive circuit and/or speed control circuit to be placed in the inner diameter part of the core,
In addition, the circuit board area is small, the space factor is excellent, and assembly standardization and automation are easy.
To provide a brushless motor that can always have a common circuit board configuration.

Hereinafter, the present invention will be explained with reference to the embodiments shown in FIGS. 3 and 4. However, the same parts having the same configuration as those of the conventional example shown in FIGS. 1 and 2 are given the same reference numerals, and a detailed explanation of those parts will be omitted.

In FIGS. 3 and 4, stator core 19
A plurality of convex poles 19b are formed on the outer periphery of the convex poles 19b as in the case of the conventional example, and these convex poles 19b
The drive coil 10 is wound around the drive coil 10, but the difference from the conventional example is that the drive coil 10 is formed in an annular shape as a whole by forming a hollow part 20 in the center. A circuit board 21 is disposed below the stator core 19. The base material of the circuit board 21 is made of an iron plate, an insulating layer is formed on the surface thereof, and a wiring pattern is formed on the insulating layer facing the hollow part 20 of the stator core 19. A circuit component 18 configuring a drive circuit for exciting the drive coil 10, a speed control circuit, etc. on the circuit board 21 is connected between the wiring patterns. Therefore, the circuit component 18 is housed in the hollow portion 20 of the stator core 19. In this case, each circuit component 18 is preferably a chip-shaped component. Further, in order to form the circuit more compactly, a thick film IC may be used.
The circuit board 21 is placed on the small flange at the lower end of the bearing holder 6 with a hole in its center passing through the bearing holder 6, and a part of the bearing holder 6 is caulked so that the circuit board 21 is attached to the bearing holder 6. The bearing holder 6 is fixed at the center of the circuit board 21. Above stator core 1
9 is placed on a circuit board 21 , and a stator core 19 is fixed to the circuit board 21 with screws 14 . Note that the reference numeral 22 is a terminal plate formed to protrude from the substrate 21, to which a lead wire 23 for connection to a power source or the like is connected.
Further, reference numeral 24 is a speed setting variable resistor. The shape of the circuit board 21 is as shown in FIGS. 3 and 4, with terminal portions 22 partially protruding toward the outer periphery.
Except for this, the outer shape is formed to be substantially the same as the outer peripheral shape of the yoke 2 of the rotor 1, and the area of the circuit board 21 is kept to the necessary minimum.

Now, when the drive circuit formed on the circuit board 21 sends a current to the drive coil 10 based on a detection signal of the rotor 1 by a magnetic pole detection element (not shown),
Torque in a predetermined direction is generated in the rotor 1, and the current to the drive coil 10 is controlled every time the rotor 1 rotates by a predetermined angle due to this torque.
is continuously rotated in a predetermined direction. The rotational speed is controlled by comparing the detection signal of the speed detector G with the set value of the speed setting variable resistor 24.

As described above, according to the above embodiment, the stator core is formed into an annular shape by forming the center hollow, and the circuit components are housed in the hollow part of the stator core, and the shape of the circuit board is similar to that of the rotor. Since it is formed to have substantially the same outer peripheral shape as the yoke, the area of the circuit board is reduced, and a brushless motor that is small and has a good space factor can be provided. Further, since the base material of the circuit board 21 is made of an iron plate, there is no need for a yoke plate as seen in conventional brushless motors, and there is an advantage that the motor can be made thinner and more compact.

As described above, according to the present invention, the area of the circuit board is reduced, and in addition to being able to provide a compact brushless motor with a good space factor, the drive circuit and/or speed control circuit is Because it is possible to have a uniform configuration without considering external circuits, standardization of assembly,
It is possible to achieve automation, always use a common circuit board configuration, and provide a brushless motor with low production costs. In addition, since the base material of the circuit board is a steel plate, the circuit board serves as a base, and the annular stator core and bearing holder can be placed directly on the circuit board. Therefore, there is no need to separately provide a base material for arranging the stator core and bearing holder, and the number of parts can be reduced.
Thinness can be achieved by reducing the axial dimension. Furthermore, since the circuit board has the function of a shield plate that prevents magnetic flux from leaking to the outside, there is no need to provide a separate shield plate, and from this point of view it can also be made thinner and more compact. .

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an example of a conventional brushless motor, FIG. 2 is a partially sectional plan view of the same brushless motor, FIG. 3 is a longitudinal sectional view showing an embodiment of the present invention, and FIG. 4 is a longitudinal sectional view showing an example of a conventional brushless motor. FIG. 3 is a partially sectional plan view of the embodiment same as the above. 1...Permanent magnet rotor, 2...Yoke, 4...
Rotating shaft, 6...Bearing holder, 10...Drive coil, 18...Circuit component, 19...Stator core,
20...Hollow part, 21...Circuit board.

Claims (1)

[Claims for Utility Model Registration] A permanent magnet rotor having a plurality of pairs of magnetic poles fixed to the inner peripheral surface of a substantially dish-shaped yoke, a drive coil being wound around a plurality of convex poles facing the rotor, and , an annular stator core having a hollow part in the center, a bearing holder having a bearing for the rotating shaft of the rotor, a wiring pattern facing the hollow part, on which the stator core is placed, and a bearing holder having a bearing for the rotating shaft of the rotor; The base material on which the bearing holder is arranged is made of an iron plate, and the circuit board is formed to have substantially the same outer circumferential shape as the yoke except for the terminal portion protruding from a part of the outer circumference, and at least the drive coil is excited. configuring a drive circuit for on the circuit board, and
A brushless motor comprising a circuit component connected to and housed in a wiring pattern of the circuit board located corresponding to the hollow part of the stator core.