JPH025659Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small motor used as a drive source for a cassette tape running system in, for example, a cassette mechanism of a car stereo.

Generally, a car stereo uses a small motor 2 as a drive source for driving a tape running system (not shown) of a cassette mechanism 1, as shown in FIG. This type of motor must maintain its rotational speed constant, and is equipped with a speed governor for this purpose. FIG. 2 shows the external appearance of a conventional motor of this type. The motor shown in A is a mechanical governor type motor, and only the power terminal portion 3 is exposed externally. The one shown in B is an electronic governor type motor.
A printed circuit is formed on the end bracket 4 of the motor, and electronic governor circuit components are placed thereon, and since the circuit components are exposed to the outside, there is a problem in that care must be taken when handling them. C and D show motors that are made stronger against electrical noise by replacing the shield case 5 with those of A and B, respectively.

By the way, in car stereos and the like, lead wires for circuits and the like must be handled within a very limited space, making the work cumbersome and prone to miswiring. Therefore, as shown in FIG. 3, a printed circuit board 6 is provided on the end bracket of the motor 2, and this circuit board is used as a relay to simplify the work and prevent wiring errors. However, as is clear from the structure of the motor described above,
In an electronic governor motor or the like in which the motor is already provided with a circuit board, it is impossible to further provide a board for relaying. For this reason, this type of motor has disadvantages in that it is very troublesome to handle the lead wires, and there is also a high possibility that incorrect wiring will occur.

The present invention was developed in order to eliminate the drawbacks of the conventional ones as described above, and is a cover that is provided on the outer periphery of a printed circuit board such as a control circuit for the purpose of shielding. By forming a printed circuit board holding portion on the member and holding another printed circuit board in the holding portion, the additional board can be used as a relay, simplifying lead wire processing work and reducing errors. The purpose of the present invention is to provide a small motor that can prevent wiring.

Embodiments of the present invention will be described below with reference to FIG. 4 and subsequent figures.

4 and 5 are a perspective view and a sectional view, respectively, showing an embodiment of a small motor according to the present invention. In the figure, 10 is a rotor, 11 is a stator case, 12 is a magnet, 13 is a commutator, and 14 is a stator case.
15 is a brush, and 15 is an end bracket. The end bracket 15 is made of an iron-based copper clad plate or a hollow copper plate, and a circuit pattern is printed on the surface of the end bracket 15, and a chip component 16 is bonded to the first plate, which constitutes a motor control circuit.
It also serves as a printed circuit board for control circuits. This end bracket 15, which also serves as a control circuit board, is fixed to the stator case 11 by caulking or the like, and is attached to the rotating shaft 10 of the rotor 10.
One end of a is supported on the shaft. The other end of the rotating shaft 10a is supported by the stator case 11, and its tip protrudes to the outside, and a pulley 17 is fixed thereto. As described above, the stator case 11 and the end bracket 15 accommodate the magnet 12 as a stator fixed to the inner peripheral surface, and the rotor 10 that rotates in cooperation with the magnet 12.
It also constitutes a cylindrical case that rotatably supports the rotating shaft 10a of the rotor 10.

18 is stator case 11 to prevent electrical noise.
The shield plate is wound in multiple turns around the outer circumference of the shield plate, and its height is greater than the height of the chip component 16 on the end bracket 15, and the height of the outer circumference is greater than that of the inner circumference. It's on. As a result, the stepped portion 18a formed between the inner circumferential portion and the outer circumferential portion has a disk-shaped relay printed circuit board 19 as a second printed circuit board having a diameter that substantially matches the inner diameter of the outer circumferential portion. is placed on the shield plate 18, and is fixed by the step portion 18a and the free piece 18b by bending the free piece 18b provided on the outer periphery of the shield plate 18 inward.

In the above-mentioned embodiment, the shield plate 18 is wound in a plurality of turns, and a step is provided between the inner circumference and the outer circumference, and the relay printed circuit board 19 is placed on the step 18a. The method of fixing the substrate 19 is not limited to this. For example, as shown in FIG. 6, a notch 18c may be formed in the shield plate 18, and a protrusion 19a provided on the outer periphery of the printed circuit board 19 may be fitted into this notch 18c. In this case, it is not necessary to wind the shield plate 18 in multiple turns or to provide the stepped portion 18a.

In addition, in the illustrated embodiment, the end bracket 15
is also used as a control circuit board, but the present invention can also be applied to motors that have a separate control circuit board as in the past.

Furthermore, although the above embodiment is explained on the assumption that a relay printed circuit board is provided, this board is not used as a relay, but a set-side circuit is placed on it, or conversely, a motor A filter circuit or the like may also be included.

As described above, according to the present invention, a shield plate is wrapped around the outer periphery of a cylindrical case along the outer periphery, and the first printed circuit board is housed inside the shield plate, and the shield plate wrapped in the above-mentioned A printed circuit board holder is provided in the opening at a position higher than the electronic components attached to the first printed circuit board, and a second printed circuit board electrically connected to the first printed circuit board is provided in the opening.
Since the printed circuit board is fixed so as to close the opening of the wrapped shield plate, it is difficult to connect the small motor with two
Two printed circuit boards will be installed, and even if one is used for the control circuit, if the other is used as a relay, it will be easier to handle the lead wires, and incorrect wiring due to work errors will be less likely to occur. , the space factor is improved, which has a great effect on downsizing the equipment.

In addition, with the above configuration, the height of the shield plate inevitably increases, which increases the shielding effect against electrical noise, and furthermore, one board covers the other board. Therefore, if the other board is used for the control circuit, the accident of touching the adjustment element made up of semi-fixed resistors in the control circuit will be prevented, and quality stability will also be improved. .

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of a conventional small motor;
2 and 3 are perspective views showing an example of the use of a conventional small motor, FIGS. 4 and 5 are a perspective view and a sectional view showing an embodiment of the small motor according to the present invention, respectively, and FIG. 6 is a perspective view showing an example of use of a conventional small motor. 5 is a partial perspective view showing a modification of a portion of the motor shown in FIG. 4. FIG. 11... Stator case, 15... End bracket, 18... Shield plate, 18a... Step portion,
18b...Free piece, 18c...Notch, 19...
Printed board.

Claims (1)

[Claims for Utility Model Registration] A stator fixed to an inner circumferential surface, a rotor that rotates in cooperation with the stator, a rotor that accommodates the stator and the rotor, and rotatably supports the rotating shaft of the rotor. A small motor comprising: a cylindrical case; and a first printed circuit board on which electronic components constituting a control circuit are mounted and fixedly attached to one end of the cylindrical case; a shield plate that is wrapped around the outer circumferential portion of the case along the outer circumferential portion and accommodates the first printed circuit board inside; and
a printed circuit board holder provided at a higher position than the electronic components attached to the first printed circuit board; The second part fixed to the printed circuit board holding part
A small motor comprising: a printed circuit board;