JPH09117107A - Dc synchronous motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a motor and to prevent a control circuit from becoming unstable owing to heat generation and characteristics from changing by mounting a circuit board at the flange of a bobbin and extending it toward the outside in the radius direction of the bobbin. SOLUTION: A mounting part 15 for mounting a circuit board 9 is provided at the outer edge part of one flange 6a in a bobbin 6 and a joining surface 15a for joining the circuit board 9 is formed along the radius direction of the bobbin 6 at the mounting part 15. Then, by bringing the circuit board 9 into contact with the joining surface 15a and soldering and fixing the circuit board 9 to a terminal 16, the circuit board 9 can be mounted along the radius direction of the bobbin 6 while it is extended, thus reducing the number of components, miniaturizing the motor, reducing cost, and at the same time isolating a control circuit from a coil winding which serums as a heat source, and hence preventing such problem as drifting and accurately controlling a speed with improved durability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous motor driven by a DC power supply, and more particularly to a DC synchronous motor having a control circuit for controlling rotation of the motor.

[0002]

2. Description of the Related Art As a DC synchronous motor of this type, a PM stepping motor is used and a permanent magnet synchronous motor is driven by a DC power source.

PM type stepping motors are generally
The rotor is provided with a plurality of poles magnetized on the outer circumference, and two sets of stators arranged outside the rotor and having the same number of pole teeth as the magnetic poles of the rotor. These two sets of stators
The rotors are arranged side by side in the axial direction of the rotor, and the phases of their pole teeth are shifted by 1/2 pitch.

Further, each of the stators is provided with a single-phase or double-winding coil, and these coils are connected to a power source via a switching element such as a transistor. The switching element is opened and closed by a control circuit, and a constant voltage circuit is provided between the power supply and the control circuit in order to prevent fluctuations in the rotation speed of the rotor due to fluctuations in the power supply voltage.

On the other hand, in the permanent magnet type synchronous motor, only one set of stators having the same number of pole teeth is provided on the outer circumference of the rotor, and the magnetic poles of the rotor and the stator are made asymmetric so that the rotor can be started. ing. The stator is excited by a single-phase coil, and a switching element is connected to the coil. Opening and closing of the switching element is controlled by the control circuit. Also, this motor is also provided with a constant voltage circuit in order to make the supply voltage to the control circuit constant.

As described above, when the synchronous motor is driven at a constant rotation speed by using the DC power supply, the switching element for energizing the coil at a good timing, the control circuit for determining the switching timing, and the DC power supply A constant voltage circuit is indispensable for keeping the number of oscillations of the control circuit constant even if there is some voltage fluctuation. Therefore, in such a DC synchronous motor, it is necessary to secure a space for accommodating the control circuit and the constant voltage circuit outside the motor body, and as a result, it has been difficult to downsize the device.

As a method for solving such a problem, for example, a motor disclosed in Japanese Utility Model Publication No. 6-46212 has been proposed. This motor is a circuit board in which a cylindrical portion is formed on one side of a flange of a bobbin that holds a coil, a gap is formed between the casing and the flange by the cylindrical portion, and a drive circuit is provided in the gap. And the circuit board is fixed to the bobbin.

By adopting such a structure, the circuit board including the drive circuit is arranged in the same casing as the motor. That is, the motor described in the above publication intends to be more compact than the case where the circuit board is separately arranged by integrally including the drive circuit.

[0009]

However, the above-mentioned motor has the following problems. First, the motor has a drive circuit mounted very close to the bobbin for compactness. However, the coil wound around the bobbin serves as a heat source that generates heat when the motor operates, and during continuous operation, the drive circuit is placed under severe temperature conditions. As a result, there is an inconvenience that the oscillation by the oscillation circuit incorporated in the drive circuit becomes unstable, or it becomes difficult to perform constant rotation speed control or the like due to drift.

Secondly, although the above-mentioned motor is intended to be made compact as a whole, since the circuit board is basically arranged at a position in series with the bobbin, the axial dimension of the motor is small. There is an inconvenience that the number is increased and the thickness cannot be reduced. That is, when only a thin storage space can be secured in the device in which the motor is to be incorporated, the motor may not be adopted.

The present invention has been made in view of the above-mentioned circumstances, and aims at downsizing the entire DC synchronous motor including a control circuit and destabilizing the control circuit due to heat generation of the coil. An object of the present invention is to provide a DC synchronous motor that can prevent characteristic fluctuations and the like and can minimize axial dimensions.

[0012]

In order to achieve the above object, the present invention provides an annular bobbin having a pair of flanges arranged in a casing and arranged at parallel intervals, and the bobbin between the flanges. A winding circuit wound around the bobbin; a rotor rotatably supported by the casing in the bobbin; and a circuit board on which a control circuit for converting the supplied direct current power to alternating current and supplying the alternating current to the winding is mounted. However, a DC synchronous motor is proposed in which the circuit board is attached to the flange of the bobbin and extends outward in the radial direction of the bobbin.

In the above DC synchronous motor, the flange to which the circuit board is attached is provided with a terminal connected to the winding in a protruding state, and the winding and the control circuit of the circuit board are connected via the terminal. It is preferable to connect.

[0014]

According to the DC synchronous motor of the present invention, the DC power supplied to the control circuit is converted into AC and supplied to the winding, and the rotor arranged in the annular bobbin around which the winding is wound is provided. Is rotated. Since the circuit board on which the control circuit is mounted is attached to the flange of the bobbin, the part that functions as an actuator, including the winding and rotor, and the control circuit that drives this are integrated into a single unit for a compact overall size. Can be realized.

Further, by extending the circuit board outward in the radial direction with respect to the bobbin, the control circuit and the winding are prevented from being arranged close to each other. This makes it possible to keep the control circuit away from the heat source winding, and to prevent problems such as drift from occurring. Moreover, with such a configuration, the axial length of the DC synchronous motor can be reduced to the minimum required for the portion functioning as an actuator, and the thickness can be reduced.

Furthermore, by providing a terminal projecting from the bobbin, by winding the end of the wound winding around the terminal, the workability of the winding process is improved and the winding is performed through the terminal. By associating the control circuit with the control circuit, the assembling work can be performed very easily.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a DC synchronous motor according to the present invention will be described below with reference to FIG. The DC synchronous motor 1 according to this embodiment includes a rotor 5 rotatably mounted in a casing 4 including a casing body 2 having a substantially bottomed cylindrical shape and a gear cover 3 closing an end opening of the casing body 2. An annular bobbin 6 arranged around the rotor 5 and a winding 7 wound around a cylindrical portion 6c between the pair of flanges 6a and 6b of the bobbin 6.
Is provided. A circuit board 9 having a control circuit 8 for driving the rotor 5 is fixed to the bobbin 6. In the figure, reference numeral 10 is an output shaft, 11 is a rotation shaft, and 1
Reference numeral 2 is a rotor magnet, 13 is a reduction gear, and 14 is a cover.

The bobbin 6 is provided with a mounting portion 15 for mounting the circuit board 9 on the outer edge portion of one flange 6a thereof. The mounting portion 15 has a circuit board 9
A fastening surface 15a for fastening is formed along the radial direction of the bobbin 6, and the circuit board 9 is brought into contact with the fastening surface 15a and fixed to the terminal 16 by soldering. The bobbin 6 can be attached in an extended state along the radial direction.

Further, in the vicinity of the mounting portion 15, for example, a terminal 16 is provided which protrudes from the outer edge portion of the bobbin 6 in the radial direction, has its tip bent at a right angle, and is arranged parallel to the axial direction. On the other hand, the circuit board 9 is formed with a terminal hole 17 through which the terminal 16 is inserted. Further, the circuit board 9 is provided with a connector 18 having a connection port arranged radially outward of the rotor 5, so that the circuit board 9 can be connected to an external board, a connector or the like (not shown).

The case of assembling the DC synchronous motor 1 having such a structure will be described below. First, in the winding step, the winding 7 is wound around the cylindrical portion 6c of the bobbin 6 while rotating the bobbin 6. In this embodiment, since the terminal 16 is provided in the protruding state on the mounting portion 15 of the bobbin 6, by winding the end of the winding 7 around the terminal 16, a simple end treatment can be performed, Workability of the process can be improved.

Next, the circuit board 9 is attached to the bobbin 6 around which the winding wire 7 is wound. At this time, the terminal hole 17 of the circuit board 9
The circuit board 9 is fixed to the fastening surface 15a of the bobbin 6 while the terminal 16 provided on the bobbin 6 is penetrated, and the terminal 16 and the circuit board 9 are connected by soldering. Connector 18
May be fixed to the circuit board 9 in advance by soldering or the like.

The circuit board 9 constructed in this way
The bobbin 6 with a rotor, the rotor 5, the reduction gear 13 and the like are housed in the casing body 2, the end opening of the casing body 2 is closed by the gear cover 3, and the cover 14 is covered around the circuit board 9 from the right side in the drawing. Thus, the DC synchronous motor 1 is constructed.

Therefore, according to the DC synchronous motor 1 thus constructed, the circuit board 9 is attached to the flange 6, so that the number of constituent parts can be reduced, and the size and cost can be reduced. Further, since the circuit board 9 is attached so as to extend radially outward from the attachment portion 15 provided on the outer edge portion of the flange 6, the winding 7 serving as a heat source.
It is arranged at a position away from and is prevented from being affected by heat from the winding 7. That is, it is possible to prevent the control circuit 8 mounted on the circuit board 9 from being exposed to a severe temperature environment, prevent the occurrence of drift, etc., and make the rotation speed control durable and accurate over a long period of time. Can be done.

Further, since the circuit board 9 is arranged so as to extend outward in the radial direction of the bobbin 6, the axial dimension of the DC synchronous motor 1 is the minimum dimension that can function as an actuator. 1 can be made thinner. Moreover, the terminal 16 provided in the protruding state on the bobbin 6 can extremely easily carry out the end treatment work of the winding wire 7 and the assembly work of the circuit board 9 in the winding process. Therefore, the number of manufacturing steps can be reduced and the cost can be reduced.

The DC synchronous motor 1 according to the present invention is
The present invention is not limited to the above embodiment, and for example, FIG.
It is also possible to adopt various modifications as shown in FIG. In FIG. 2, the terminal 16 provided on the bobbin 6 is attached to the mounting portion 1.
5 is made to project from the fastening surface 15a of No. 5 in parallel with the rotating shaft 11. 3 and 4, the direction of the connector 18 in FIGS. 1 and 2 is provided parallel to the rotating shaft 11 of the rotor 5. In FIG. 5, the fastening surface 15a of the mounting portion 15 is inclined. In the cases of FIGS. 3 to 5, the radial dimension of the DC synchronous motor 1 can be reduced as compared with the cases of FIGS. 1 and 2.

Further, in the case of FIGS. 3 to 5, divided covers 14a and 14b are adopted. The DC synchronous motor 1 shown in FIGS. 2 to 5 also has the same operation and effect as the DC synchronous motor 1 of the present embodiment shown in FIG.

[0027]

As described above, in the DC synchronous motor according to the present invention, by mounting the circuit board on the bobbin, the overall size of the DC synchronous motor including the control circuit can be reduced, and at the same time, the coil serving as the heat source can be used. Since the control circuit can be separated, it is possible to prevent the occurrence of problems such as drift and to maintain durable and highly accurate rotation speed control.

Further, by disposing the circuit board so as to extend in the radial direction of the flange, there is an effect that the axial dimension of the DC motor can be suppressed to a minimum and the thickness can be reduced. In addition, the terminals protruding from the flange can improve the terminal processing work in the winding process and the circuit board assembly work.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a DC synchronous motor according to the present invention.

FIG. 2 is a vertical cross-sectional view showing a second embodiment of the DC synchronous motor of FIG.

3 is a vertical cross-sectional view showing a third embodiment of the DC synchronous motor of FIG.

FIG. 4 is a vertical cross-sectional view showing a fourth embodiment of the DC synchronous motor of FIG.

5 is a vertical cross-sectional view showing a fifth embodiment of the DC synchronous motor of FIG.

[Explanation of symbols]

 1 DC synchronous motor 4 Casing 5 Rotor 6 Bobbin 6a, 6b Flange 7 Winding 8 Control circuit 9 Circuit board 16 Terminal

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kazumasa Yoshida 1-297 Kitabukuro-cho, Omiya-shi, Saitama Mitsubishi Materials Corp. Research Institute (72) Inventor Mikio Hashimoto 1 at 46, Chifuku, Susono-shi, Shizuoka Higashi Co., Ltd. Inside the Fuji Works (72) Inventor Shigekatsu Ono 1 at 46 Sifuku, Susono City, Shizuoka Prefecture Higashi Fuji Works Co., Ltd.

Claims (2)

[Claims] 1. An annular bobbin having a pair of flanges arranged in a casing and arranged in parallel with each other, a winding wound around the bobbin between the flanges, and freely rotatable in the casing arranged in the bobbin. And a circuit board on which a control circuit for converting the supplied DC power to AC and supplying it to the winding is mounted, the circuit board being attached to the flange of the bobbin,
A direct-current synchronous motor, which is extended outward in the radial direction of the bobbin. 2. A flange to which the circuit board is attached is provided with a terminal connected to the winding in a protruding state, and the winding and the control circuit of the circuit board are connected via the terminal. The DC synchronous motor according to claim 1, which is characterized in that.