JPH0226225Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) This invention relates to improving the efficiency of an axial gap type coreless motor.

In recent years, the spread of audio equipment that uses dry batteries as a power source has been remarkable, and with the trend toward miniaturization in portable headphone stereo players and the like, there is a demand for smaller and thinner DC motors that drive the tape. However, as devices become smaller and thinner, their efficiency deteriorates and battery life becomes a problem.

(Problems to be Solved by the Prior Art and Ideas) Conventionally, an axial gap type coreless motor used in this type of portable headphone stereo player has a structure as shown in FIG.

That is, a flat rotor 4 with a plurality of molded rotor coils 4a is placed inside a bracket 3 in which a casing 1 and a flat field magnet 2 are arranged, and a flat rotor 4 is placed in the space between the magnet 2 and the inner ceiling of the casing 1. The winding start terminals 4b of each of the rotor coils are respectively led out from the inner diameter of each rotor coil and connected to each terminal terminal 5a of the commutator 5. In the figure, 6 and 7 are metals fixed to the casing 1 and bracket 3, respectively, and the rotor 4 is connected to the shaft 8.
The commutator 5 is rotatably supported through the commutator 5, and 9 is a brush that comes into sliding contact with the commutator 5. Further, 4c is a magnetic plate that constantly attracts and biases the rotor 4 toward the bracket 3, and 7a is a thrust plate that pivotally supports the rotor 4.

In such a configuration, as can be seen from the drawings, the rotor 4 and magnet 2 are connected in order to increase efficiency.
In order to reduce the gap, the inner diameter of the magnet 2 should be adjusted so as to avoid the winding start end 4b of each rotor coil, that is, the inner diameter of the magnet 2 should be larger than the coil winding start end pull-out part 4d of each rotor coil. need to be set. Therefore, as shown in FIG. 2, the effective cross-sectional area of the magnet 2 that spans the effective conductor length portion 4e of each rotor coil 4a, which is derived from Fleming's left-hand rule, is halved, resulting in an efficient This is not desirable and has become a hindrance to downsizing the DC motor itself.

In addition, as a countermeasure for this, as shown in FIG. 3, the field magnet 22 is constructed so that the inner diameter of each rotor coil 4 is arranged inside the coil winding start terminal pull-out portion 4d, that is, the effective cross-sectional area is increased. Things that were used for it also began to be used.

However, in such a configuration, as can be seen from the drawing, there is a coil terminal 4d..., so the air gap between the field magnet 22 and the rotor 4 must be set large, and this tendency is caused by a low voltage of about 1.5V. In a motor driven by a motor, the rotor coil also has a thick wire, which worsens the problem, and if an unreasonable gap is set, depending on the dimensional position of the rotor, there is a risk that the short end of the coil 4b may come into contact with the field magnet 22. .

In addition, as disclosed in Japanese Patent Publication No. 57-4175, ``In a concentric sliced coil formed by thinly cutting with a wire cut, a groove reaching the inner winding start end is formed by cutting and an insulating treatment is performed. It is also possible to insert one end of the lead wire other than the winding start end itself into this groove and connect it to the inner winding start end, but this configuration makes it difficult to insert the lead wire, solder, etc. inside the narrow coil. It is extremely difficult to work with, and furthermore, cutting grooves (grooves cannot be made without cutting) are added to the thinly sliced coil, which increases the resistance of that part, increases copper loss, and deteriorates the electrical characteristics. The coil is not desirable from above, but in fact, with this kind of cutting, burrs occur on the conductor at the cut end, and rare shorts occur between adjacent conductors, so it has no practical use and is completely unmarketable.

This idea involves winding a round wire several times to several dozen times per layer, and partially pressing the rotor coil made by winding the round wire in multiple layers, so that the winding space factor does not protrude to the other surface. This was created by focusing on the fact that it is easy to compress and create a recess, and it overcomes the above defects by creating a simple structure without increasing the number of man-hours, ignoring the meaningless thickness of the coil terminal. The present invention provides an axial gap type coreless motor with an extremely low profile that increases efficiency by making the gap small and prevents contact between the coil terminal and the magnet.

[Structure of the invention] (Means for solving the problem) This invention connects the coil winding start terminals derived from the inside of each rotor coil to the commutator pieces, and also connects these rotor coils so that they do not overlap each other. In the axial gap type coreless motor, the field magnet is disposed equally in the inner diameter of each rotor coil and is molded flat as a whole, and the inner diameter part of the field magnet is provided inside the coil winding start terminal pull-out part of the inner diameter of each rotor coil. A coil is made by winding a round wire several times to several tens of times per layer, and winding this in a substantially aligned manner in multiple layers. A recess is formed in the inner diameter so as to prevent copper loss from reaching at least the inner diameter of the magnet and to prevent bending to the opposite side of the magnet, and at least a part of the terminal of each rotor coil is formed in the recess. It was designed to store the following.

(Function) In this way, copper loss does not increase and
It becomes possible to ignore the meaningless thickness of the coil terminals, making it possible to increase efficiency.

[Example] Hereinafter, the configuration of this invention will be explained based on the example shown in the drawings.

The feature of this invention is that the coil winding of each rotor coil 4a is made by winding round wires in multiple substantially aligned manners as shown in FIGS. 4 and 5, in contrast to the conventional structure shown in FIG. 3. At the time of molding, a part of the electrically ineffective conductor part on the starting terminal lead-out surface is pushed into the commutator side with a width several times the thickness of the coil terminal, as shown in Figure 6. Therefore, a recess 4f is formed at the same time as the molding, and the winding start terminals 4b of each rotor coil are housed in the recess 4f. In the figure, the same parts as those in FIG. 3 are denoted by the same reference numerals, and the explanation thereof will be omitted.

Since this device is configured as described above, the recess 4
Since f is formed at the same time as the molding of the rotor, it can be done extremely easily without increasing the number of man-hours, and as a result, from the viewpoint of characteristics, the diameter of the field magnet 22 can be made as small as possible. Moreover, since the recess 4f is formed by press forming without cutting a part of the conductor, the occupation density of the round wire only partially increases.
There is no risk of increased copper loss unlike in the case of a cut structure. This makes it possible to ignore the meaningless thickness of the coil terminals, and by reducing the air gap, high efficiency and low current can be achieved, and there is no contact between the rotor and the field magnet. be.

In the above embodiment, the concave shape is simultaneously formed during the molding process in which the rotor is heated, but it is of course possible to form the concave shape immediately after winding.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the main parts of a conventional axial gap type coreless motor, Fig. 2 is a plan view of the main parts of the same motor, and Fig. 3 is a main part of another conventional axial gap type coreless motor. FIG. 4 is a sectional view of the main part of the motor of the present invention, FIG. 5 is a plan view of the main part, and FIG. 6 is an enlarged sectional view of the main part of the recess. 22 is a field magnet, 4 is a rotor, 4a is a rotor coil, 4b is a rotor coil winding start terminal, 4
d is the rotor coil winding start terminal drawer part, and 4f is the recess.

Claims (1)

[Scope of utility model registration request] While connecting the coil winding start terminals derived from the inside of each rotor coil to the commutator pieces,
These rotor coils are arranged equally so that they do not overlap each other and are molded flat as a whole, and the inner diameter part of the field magnet is a shaft provided inside the coil winding start terminal draw-out part of the inner diameter of each rotor coil. In a directional gap type coreless motor, the rotor coil is made by winding a round wire several times to several dozen times per layer.
It is made by winding this in multiple layers in approximately aligned manner,
The electrically ineffective conductor portion of each rotor coil winding start terminal terminal surface is designed so that there is no increase in copper loss from the inner diameter to at least the inner diameter of the magnet, and to prevent it from being bent to the opposite side of the magnet. An axial gap type coreless motor comprising a recess formed therein and at least a portion of each of the rotor coil terminals accommodated in the recess.