JPH038075Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a brushless motor in which a coil and a coil drive circuit for energizing and disconnecting the coil are arranged on a substrate.

[Technical background of the invention]

For example, in the case of an axial gap type brushless motor, a coil is arranged on the board and
A coil drive circuit and a control circuit for controlling this coil drive circuit are formed on this board using a printed wiring method in which, for example, copper foil on the board is etched to form an arbitrary wiring pattern. The rotor is rotatably disposed via a gap. Conventionally, in order to reduce the size of the board, it has been common practice to configure the board with a double-sided printed circuit board with wiring patterns formed on both sides, and to improve the magnetic properties, a yoke is superimposed on this double-sided printed circuit board. is being carried out.

[Problems with background technology]

In the above conventional configuration, the board is made of a double-sided printed circuit board and the wiring pattern is also formed on the side on which the yoke is stacked, so an insulating plate must be provided between the board and the yoke, which reduces the number of parts. In addition, the distance between the yoke and the coil becomes longer due to the thickness of the insulating plate, which in turn increases magnetic resistance, making it impossible to sufficiently improve motor efficiency. It was hot. Moreover, double-sided printed circuit boards are inherently expensive, and in order to make the wiring patterns on each side conductive with each other, a through hole is formed in the board and then the inner peripheral surface of the through hole is plated to form a so-called through hole. Because it is necessary, the processing cost of the board is high, which leads to the problem that the manufacturing cost of the entire motor increases.

[Purpose of invention]

The present invention has been made in view of the above circumstances, and its purpose is to provide a brushless motor that can reduce the number of parts and improve efficiency, as well as reduce manufacturing costs.

[Summary of the idea]

In this invention, a wiring pattern for a coil drive circuit is formed on one side of a board using a printed wiring method, an insulating layer with through holes for connecting the wiring pattern is provided on this wiring pattern, and a conductive coating is applied on this insulating layer. By forming the wiring pattern of the control circuit by forming the wiring pattern of the control circuit and connecting the wiring pattern of the control circuit to the wiring pattern of the coil drive circuit through the through hole for connecting the wiring pattern, wiring can be performed only on one side of the board. The feature is that a pattern is formed, making an insulating plate unnecessary.

[Example of idea]

The following is an example of applying the present invention to an axial gap type brushless motor.
This will be explained with reference to the figures. 1 is a base, 2 is a bearing cylinder installed approximately at the center of the base 1, and 3 is a mounting plate made of magnetic material. The surrounding of the fitting hole 3a is depressed in an annular shape, and with the fitting hole 3a fitted into the bearing cylinder 2, three mounting legs 3b formed at equal angular intervals on the outer circumference are attached to the base 1. It is fixed with screws. Reference numeral 4 denotes an annular board, which is made of a so-called single-sided printed circuit board with copper foil pasted on one side, for example, and a plurality of boards are mounted on the mounting plate 3 through a yoke 5 having an annular plate shape and with the copper foil side facing upward. It is fixed by two eyelets 6. On the upper surface of this substrate 4, for example, six coils 7 are arranged intermittently in the circumferential direction and fixed by adhesive, and a coil drive circuit 8 for turning off the current to the coils 7 and this coil drive circuit 8. A control circuit 9 is configured to control the. As shown in FIG. 3, the coil drive circuit 8 includes an output transistor 10, and by switching the output transistor 10, the current to the coil 7 is cut off. is formed by a printed wiring method in which an etching resist is printed on the copper foil of the substrate 4 and then etched to obtain a desired copper foil pattern. Further, the control circuit 9 includes, for example, three Hall elements 12 that detect the rotational position of the rotor, which will be described later, and a differential amplifier 13 that receives an output from each Hall element 12. The output transistor 10 of the coil drive circuit 8 is controlled based on a signal, and its wiring pattern 14 is formed as follows. That is, after forming the wiring pattern 11 of the coil drive circuit 8 on the substrate 4 by the printed wiring method as described above, the intermediate insulating layer 15 is printed on the wiring pattern 11.
Thereafter, a conductive paint or conductive paste is printed in a predetermined pattern on this intermediate insulating layer 15 to form the wiring pattern 14 of the control circuit 9, and a protective insulating layer 16 is further printed on the front surface thereof. (See Figure 4). Further, when printing the intermediate insulating layer 15, by forming the through holes 15a corresponding to predetermined portions of the wiring pattern 11 of the coil drive circuit 8, the conductive paste can be applied to the through holes 15 when printing the conductive paste.
a, and eventually the intermediate insulating layer 1
The upper and lower wiring patterns 11 and 14 are electrically connected to each other at a predetermined portion via the wiring pattern 5.
Furthermore, in FIGS. 2 and 5, reference numeral 16 denotes a frequency power generation coil formed by a printed wiring method on the inner circumferential side of the area where each coil 7 is arranged on the substrate 4;
is an intermediate insulating layer 1 on this frequency power generation coil 16.
5 is a cancel loop formed by conductive paste, and this cancel loop 17 is connected in series with the frequency power generation coil 16.
This is for canceling noise induced in the coil 16 by disturbance magnetic flux. In FIG. 1, 18 is a rotor in which a rotating shaft 18a is supported in a bearing sleeve 2, and this rotor has a field that faces each coil 7 of the substrate 4 and the frequency power generation coil 16 through a gap in the axial direction. It includes a magnetic magnet 19 and a frequency power generation magnet 20.

According to the above structure, since the wiring patterns 11 and 14 of the coil drive circuit 8 and the control circuit 9 are formed on the upper surface side of the substrate 4 with the intermediate insulating layer 15 in between, the substrate 4 is formed into a single-sided printed circuit board. In addition, there is no need to provide an insulating plate between the substrate 4 and the yoke 5. Therefore, not only can the number of parts be reduced accordingly, contributing to lower manufacturing costs, but also the distance between the coil 7 and the yoke 5 can be shortened, reducing magnetic resistance, which in turn reduces the overall motor It is possible to improve efficiency. Furthermore, although one of the wiring patterns is formed using a conductive paste with a small current capacity, the wiring pattern 11 of the coil drive circuit 8 through which a large current flows is formed by a printed wiring method with a large current capacity, and is Since the wiring pattern 14 of the control circuit 9 through which only current flows is formed of a conductive paste, it is possible to prevent disconnection of the wiring pattern 11 due to a large current and improve reliability. Of course, a single-sided printed circuit board is cheaper than a double-sided printed circuit board, and it does not require the highly complicated through-hole formation process of forming a hole in the board and plating its inner circumferential surface, as in the case of a double-sided printed circuit board. is not necessary at all, and conduction between both wiring patterns 11 and 14 can be established by simply forming a through hole 15a when printing the intermediate insulating layer 15 and printing so that the conductive paste enters into the through hole 15a. Since it can be made possible, overall manufacturing costs can be significantly reduced. In this case, the conductive paste is applied to the through hole 15a of the intermediate insulating layer 15.
Since the configuration is such that the two wiring patterns 11 and 14 are connected by entering the hole 15a, the wiring patterns 11 and 14 are connected over the entire area of the through hole 15a, compared to the case where the connection is made using a conventionally known through hole. ,
The connection area becomes larger, the connection strength becomes stronger, and the vibration resistance improves. Therefore, the structure is strong against vibrations generated when the brushless motor is operated. Further, in this embodiment in particular, since the mounting plate 3 is also made of a magnetic material, together with the yoke 5, the magnetic resistance can be further reduced. Furthermore, while the mounting plate 3 is arranged so as to form a part of the magnetic path in the same manner as the yoke 5, the central part of the mounting plate 3, that is, the part corresponding to the frequency power generation coil 16 of the board 4 is depressed downward. Since a relatively large gap is formed between the rotor 18 and the substrate 4, the influence of the field magnet 19 of the rotor 18 on the frequency power generation coil 16 can be prevented as much as possible.

In the above embodiment, since the intermediate insulating layer 15 and the wiring pattern 14 of the control circuit 9 are formed by printing, the thickness of the insulating layer 15 and the wiring pattern 14 can be made thinner, and the thickness of the entire substrate 4 can be made thinner. It can be shaped. Thereby, the distance between the coil 7 and the yoke 5 can be shortened, the magnetic resistance can be reduced, and the efficiency of the motor can be improved.

Figures 6 and 7 show modified examples.
The figure shows the mounting leg 3b of the mounting plate 3 attached to the base 1 with screws 21 so that the height can be adjusted, and then fixed with molding material 22. Figure 7 shows the mounting leg 3b and the base 1. 1, a compression spring 23 is fixed with a screw 21 so that the height can be adjusted.
In any of the above configurations, since the height relative to the mounting leg 3b and the inclination of the mounting plate 3 can be adjusted, the wow and flutter value of the frequency output induced in the frequency power generation coil 16 can be adjusted to a minimum. It is something that can be done.

In the above embodiment, a printed wiring method in which a copper foil adhered to an insulating substrate is etched leaving a desired wiring pattern portion is exemplified, but the present invention is not limited to this. It is also possible to use a so-called additive printed wiring method in which a plating resist from which the wiring pattern has been removed is printed and then plating is applied to form the wiring pattern.

[Effect of idea]

As described above, in the present invention, a wiring pattern for a coil drive circuit is formed on one side of a substrate by a printed wiring method, an insulating layer having a through hole for connecting the wiring pattern is provided on this wiring pattern, and an insulating layer is formed on this insulating layer. A wiring pattern for a control circuit that controls the coil drive circuit is formed using a conductive paint, and the wiring pattern for the control circuit is connected to the wiring pattern for the coil drive circuit through a through hole for connecting the wiring pattern. Therefore, there is no need to provide an insulating plate between the board and the yoke stacked on it, which makes it possible to reduce the number of parts and improve motor efficiency by lowering magnetic resistance. Although it uses a conductive coating with a small diameter, it can prevent wiring patterns from breaking, so there is no risk of any loss in reliability, and it also eliminates the need for a complicated through-hole formation process, reducing manufacturing costs. This has the effect that it can also be achieved at the same time.

[Brief explanation of drawings]

1 to 5 show an embodiment of the present invention,
Figure 1 is an overall vertical sectional view, Figure 2 is a top view of the board, Figure 3 is a block diagram of the coil drive circuit and control circuit, Figure 4 is a partially enlarged vertical sectional view of the wiring pattern, and Figure 5 is a vertical sectional view of the wiring pattern. FIG. 2 is a partially enlarged vertical cross-sectional view of the frequency generating coil taken along line V-V, and FIGS. 6 and 7 are partially enlarged vertical cross-sectional views showing different modifications of the mounting leg portion of the mounting plate. In the figure, 4 is the board, 7 is the coil, 8 is the coil drive circuit, 9 is the control circuit, 11 is the wiring pattern of the coil drive circuit, 14 is the wiring pattern of the control circuit, 1
5 is an intermediate insulating layer (insulating layer).

Claims (1)

[Scope of utility model registration request] A wiring pattern of the coil driving circuit formed on one side of the substrate by a printed wiring method, in which a coil, a coil driving circuit for energizing and disconnecting the coil, and a control circuit for controlling the coil driving circuit are arranged on a substrate. an insulating layer provided on the wiring pattern and having a through hole for connecting the wiring pattern; and an insulating layer formed by applying a conductive paint on the insulating layer and connecting the coil through the through hole for connecting the wiring pattern. A brushless motor comprising: a wiring pattern of the control circuit connected to a wiring pattern of the drive circuit.