JPS63193510A - Manufacture of coaxial type rotary transformer - Google Patents

Abstract

PURPOSE:To heighten mass productivity with good size accuracy by grinding peripheral grooves for laying windings on an inner peripheral surface while rotating a core by a roller abutted on an outer peripheral surface of the core to be used for a coaxial type rotary transformer. CONSTITUTION:A cylindrical core 101, whose outer peripheral surface is in advance grinded by a centerless grinder, is held by two rollers 102, 103, a shoe 104 and guide plates 105 and 106, the cylindrical core 101 is rotated by rotating the rollers 102 and 103, a diamond 107 for grinding peripheral grooves is inserted into an inner peripheral space of this rotating cylindrical core 101, this diamond 107 for grinding the peripheral grooves is pressed against the inner peripheral surface of the cylindrical core 101 while rotating it in order to grind the peripheral grooves. In this way, the cylindrical core is held having its peripheral surface as a reference and rotated so as to simply form coaxial peripheral grooves.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing a coaxial rotary transformer used in a video tape recorder, etc., and in particular, to a method for manufacturing a coaxial rotary transformer for use in a coaxial rotary transformer. The present invention relates to a method of grinding a circumferential groove for attaching a winding wire to a surface.

(Prior Art) FIG. 5 shows a sectional view of a coaxial rotary transformer used in video tape recorders and the like. As shown in FIG. 5, the coaxial rotary transformer includes a cylindrical ferrite core 501, an inner core having a circumferential groove 502 formed on the outer circumferential surface, a winding 503 attached to the circumferential groove 502, and a cylindrical ferrite core 501. A ferrite core 504 has a circumferential groove 505 formed on its inner circumferential surface, and an outer core having a winding 506 attached to the circumferential groove 505. They are facing each other.

The cylindrical cores used in this coaxial type rotary transformer are opposed to each other with a very small interval of 1, for example, 50 microns, and one side rotates at high speed, so the outer diameter, inner diameter, roundness, coaxiality, etc. Extremely high dimensional accuracy is required, including the position of the circumferential groove.

A conventional method for grinding a circumferential groove on the inner circumferential surface of a cylindrical ferrite core for a coaxial rotary transformer is, for example, as shown in FIG. 302 is held by a chuck 303 and rotated. Then, a circumferential groove grinding diamond 304 is inserted into the inner peripheral space of this rotating cylindrical core 301, and while rotating this circumferential groove grinding diamond 304, the cylindrical core 301 is
A circumferential groove was ground into the inner circumferential surface of the cylindrical core 301.

Another method is shown in FIG. In this method, a cylindrical core 401 is held by a chuck 402 and rotated. Then, a circumferential groove grinding diamond 403 was inserted into the inner circumferential space of the rotating cylindrical core 401, and a circumferential groove was ground on the inner circumferential surface.

(Problems to be solved by the invention) In the conventional method, it is necessary to chuck the cylindrical cores to be ground one by one, resulting in poor productivity and an increase in the number of processing steps, which makes it difficult to reduce the price of the product. The problem was that there was no.

In addition, since it is supported by a chuck, the dimensional accuracy after grinding is affected by the accuracy of chucking, and there is a problem that it is difficult to perform accurate and uniform machining.

In view of the above, it is an object of the present invention to provide a method for manufacturing a coaxial rotary transformer that can perform loading and unloading in a short time, has excellent mass productivity, and can perform highly accurate and uniform processing. It is something.

(Means for Solving the Problems) The present invention provides a method for forming a circumferential groove for winding on the inner circumferential surface of a cylindrical ferrite core used in a coaxial rotary transformer, in which the outer circumferential surface of the core is The circumferential groove is ground on the inner circumferential surface of the core while rotating the core by a roller that comes into contact with the core.

(Embodiment) FIG. 1 is a schematic diagram of an embodiment of the present invention, and FIG. 2 is a schematic diagram of FIG. 1 viewed from the direction of the arrow. To illustrate this embodiment, a cylindrical core 101 has two rollers 102, 103 . It is held by a shoe (supporting member) 104 and two guide plates 105 and 106. This roller 102 is connected to a drive source and rotates at a fixed position. Further, the roller 103 is also connected to a drive source and is movable in the direction of arrow B, and the cylindrical core 103
1, press and hold the cylindrical core 101 against 102 and the shoe 104 with a constant force,
When placing or removing item 1, move it to a position that allows the work to be done. Moreover, the shoe 104 is
The cylindrical core 101 is supported at a fixed position. Further, one guide plate 106 is fixed, and the other guide plate 105 is movable.

With the above structure, the cylindrical core 101 whose outer peripheral surface has been ground by a centerless grinder is held by two rollers, a shoe, and a guide plate, and by rotating the rollers. , rotates the cylindrical core 101, and rotates the cylindrical core 10.
A circumferential groove grinding diamond 107 was inserted into the inner circumferential space of the cylindrical core 101, and the circumferential groove grinding diamond 107 was rotated and pressed against the inner circumferential surface of the cylindrical core 101 to grind the circumferential groove.

In addition to the above method, the positioning of one cylindrical core is
By swinging the axis of the cylindrical core and applying rotational force, a propulsive force can be applied to the cylindrical core, and the cylindrical core can be brought into contact with the guide plate and positioned.

In the present invention, there is no need to chuck the cylindrical core, and the cylindrical core only needs to be placed at a portion that is held by rollers, etc., so the process is easy, and the number of man-hours can be reduced and automation is easy. In addition, since the present invention holds and rotates one cylindrical core with the outer circumferential surface as a reference, a circumferential groove having the same central axis as the outer circumference can be easily formed, and the end surface is also fixed with a guide plate, so it is extremely Can be processed with high precision.

Further, when grinding the inner circumferential surface, it may be done before or after grinding the circumferential groove.

(Effects of the Invention) The present invention provides a method for manufacturing a coaxial rotary transformer with good dimensional accuracy and excellent mass productivity, and is extremely useful industrially.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the present invention, FIG. 2 is a schematic diagram of FIG. 1 viewed from the direction of arrow A, and FIG. 3 is a schematic diagram of a conventional example. , FIG. 4 is a schematic diagram of another conventional example, and FIG. 5 is a sectional view of a coaxial rotary transformer. 101... Cylindrical core, 102... Roller, 1゜3... Roller, 104... Shoe, 105, 10
6...Guide plate, 107...Diamond for grinding inner groove. Figure 1 Figure 3 Figure 4 h$5 Figure

Claims (1)

[Claims] In a method of forming a circumferential groove for winding on the inner circumferential surface of a cylindrical ferrite core used in a coaxial rotary transformer, the core is rotated by a roller in contact with the outer circumferential surface of the core. A method for manufacturing a coaxial rotary transformer, comprising: grinding the circumferential groove on the inner peripheral surface of the transformer.