JPS587827Y2 - Japanese woodpecker - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a small-sized DC motor with a speed generator that has an improved structure and arrangement of the speed generator.

Conventionally, a speed generator I/J type DC motor uses an alternating current generator as the speed generator G as shown in Fig. 1a, and the generated voltage is rectified and then compared with a reference voltage and amplified to generate a DC motor M. In this case, either the speed generator G and the speed control circuit S are completely separate, or the speed generator G is built into the main body of the DC motor M and the speed control circuit is integrated as shown in Figure 1. Separately from the speed generator G, the motor S is mounted inside the case of the DC motor M and connected thereto.

For this reason, the temperature atmosphere of the generator rotor, which is made of ferrite, inside the motor body and the temperature atmosphere of the control circuit, especially the semiconductors, outside the main body change differently, and this causes fluctuations in the rotation speed. come.

In other words, the motor operates in a certain temperature atmosphere, but
When a motor is energized and rotated, the windings inside the motor generate heat.

As a result, a difference arises between the temperature inside the motor case and the temperature outside.

Generally, a ferrite magnet is used for the generator rotor inside the motor case, and this magnet is -0,
Based on the temperature coefficient of 18% fc, the generated voltage changes as the temperature inside the motor case increases.

On the other hand, the semiconductors (diodes, transistors, etc.) of the circuit that controls the motor using the above-mentioned generated voltage are -2 m
It has a temperature coefficient of V/'C, and if the temperature is the same, it acts to cancel both the temperature coefficient of the motor and the temperature coefficient of the semiconductor itself in the temperature compensation system.
If the circuit is installed externally, the temperature does not change,
Temperature compensation by the semiconductor elements of the circuit becomes impossible.

Therefore, this causes a drift phenomenon in which the motor rotation speed changes over time after the motor is started.

The temperature coefficient of this type of ferrite magnet is 1 degree C.
Since the magnetic flux density changes by as much as 0.18% in response to a change, the effect of heat generation from the electric motor is large.

Further, since the speed detection coil of the speed generator is located inside the motor body, magnetic noise generated by the rotation of the motor is added to the generated voltage and has an adverse effect on the control system.

In order to prevent the above-mentioned drift phenomenon, this invention places the rotor of the generator and the control circuit in the same temperature atmosphere and in close proximity to each other. This paper proposes a compact DC motor with a speed generator that has a structure that makes the overall assembly easy.

The present invention will be explained with reference to the embodiments shown in FIG. 2 and below.

In FIG. 2, the rotating shaft 1 of the motor body M protrudes from both sides of the motor body M.

One shaft end of the rotating shaft 1 is made to protrude from a case 3 placed over the motor body M through a cushion 2, and a pulley or the like (not shown) is fixed thereto.

Case 3 is attached to the end of the other rotating shaft that protrudes from the motor body.
A ferrite magnet constituting the permanent magnet rotor 4 of the speed generator is fixed inside.

The rotor 4 is placed on a printed circuit board 5 mounted in the case 3 so as to face the center of a stator 9 consisting of a comb-shaped yoke 6.7 and a speed detection coil 8.

The printed circuit board 5 includes a transistor Tr, a resistor R,
A speed control circuit S is constructed by attaching circuit components 10 such as a capacitor C, and a part of the printed circuit board 5 is made to protrude to the outside through a window 3a raised in the case 3 to provide a terminal portion 5a for a power supply to be applied to the motor.

In FIG. 2, the lid 3b of the case 3 is located under the printed circuit board 5.
cover and store the entire motor in the case.

The stator 9 of the speed generator G will be explained in more detail with reference to FIG. 3. The stator 9 of the speed generator G will be explained in more detail with reference to FIG. The comb-tooth-shaped yoke 6 is provided with a yoke 6 and an upward comb-tooth-shaped bent portion 7a.The comb-tooth-shaped yoke 7 is arranged downward in a concave portion so that the bent portions 6a and 7a forming the respective magnetic poles are interwoven with each other alternately. The comb-tooth-shaped yoke 7 is fitted inside the comb-tooth-shaped yoke 7, or the comb-tooth-shaped yoke 6 is placed on the comb-tooth-shaped yoke 7. Fit into place.

Next, a plurality of terminal portions 1b are extended downward from the periphery of the comb-shaped yoke 7, and the width of the terminal portions 1b is narrowed and stepped. 5
b, and the tip is fixed by soldering to copper foil on the back side of the printed circuit board 5.

As shown in FIG. 4, it may be fixed by twisting or bending 90 degrees on the back side of the printed circuit board 5.

In this case as well, it is desirable that the tips of the terminal portions 7b be soldered to copper foil on the back side of the printed board 5 so that the board and the yoke are electrically grounded in common.

The printed circuit board 5 is further provided with connection points on the copper foil portion 5c for connecting the DC motor and speed generator board wires, respectively.

The comb-shaped yokes 6 and 7 may be fixed as described above by fitting the inner wall of the yoke 6 to the terminal portion 1b of the yoke 7 and soldering them so that they are electrically grounded in common.
As shown in FIG. 5a, the terminal portion 6bf corresponds to the terminal portion 7b of the yoke 7! : It is provided on the yoke 6 and both terminal parts 6b and 7b are inserted and fixed together into the through hole 5b of the printed circuit board 5, or the comb-tooth-shaped yoke 6 is fitted into the comb-tooth-shaped yoke 1 as shown in Figure 5. In this case, bending pieces 6c may be provided on the yoke 6 located on both sides of the terminal portion 7b of the yoke T and bent on the back side of the yoke T to fix both yokes. Alternatively, the speed detection coil may be wound around a bobbin and It is also possible to provide projections on the upper and lower flanges, insert them into holes in the yoke, and then weld them to fix both yokes together with the coil bobbin.

If the present invention is configured as described above, the stator of the speed generator,
By fixing the terminal part and the ground part of the printed circuit board, the stator is integrally mounted on the printed circuit board,
The stator faces the rotor fixed to the rotating shaft of the motor body, and the entire motor is housed in a case, so the speed generator and the control circuit components installed on the printed circuit board are separately affected by temperature effects from the motor body. Specifically, by propagating the heat from the motor side through the terminals of the stator to the outside via the printed circuit board, the atmosphere becomes the same, improving temperature characteristics and achieving stable rotation speed. is obtained.

In addition, since the speed generator stator and circuit components are pre-assembled on the flint board, the size is reduced, the workability is extremely good, and component management is facilitated and rationalized.

Furthermore, we can provide an electric motor with excellent workability that makes assembly work extremely easy, as all you have to do is connect the motor lead wires to the printed circuit board.Furthermore, we are able to reduce the effects of noise that may enter the motor. This can be eliminated by grounding the stator via its terminals.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a conventional DC motor with a speed generator, Figure 2
The figure is an explanatory cross-sectional view of the main parts showing the internal arrangement of the case of the motor in which the micromotor spark extinguisher of the present invention is implemented.
The figure is a perspective view of the speed generator of the present invention disassembled into parts.
The figure is an explanatory diagram of a method for fixing the yoke terminal portion and the board of the same speed generator, and FIG. 5 is a side view of another embodiment of the same yoke fixing method. 1...rotating shaft, 3...case, 4...
...Rotor, 5...Printed circuit board, 5b.
...Through hole, 6,7...Comb tooth shape Yoku
7b...Terminal section, 8...Speed detection coil, 9...Stator, M...DC motor body, G...Speed Generator, S... Speed control circuit.

Claims (1)

[Scope of utility model registration request] A DC motor body, a rotor consisting of a permanent magnet fixed to the rotating shaft of the DC motor body, and a stator having a speed detection coil arranged in a comb-shaped yoke that faces each other so as to intertwine alternately from both sides are attached to the rotor. The speed generator and the
In a DC motor comprising a printed circuit board provided with a speed control circuit for controlling the speed of the DC motor using the output voltage of the speed generator, a terminal portion is provided extending from at least one side of the comb-shaped yoke, and a terminal portion is provided on the printed circuit board. The above-mentioned terminal section is inserted and fixed into the drilled through hole, the ground section of the printed circuit board is connected to this terminal section, the stator of the speed generator is integrally formed on the above-mentioned printed circuit board, and this stator is connected to the ground section of the printed circuit board. A small DC motor with a speed generator, characterized in that it is mounted in the same case as the DC motor, facing the rotor of the speed generator.