JPH0478162B2 - - Google Patents

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 in the axial direction of a cylindrical ferrite core for a coaxial rotary transformer. This invention relates to a method of grinding both end faces.

(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, in the coaxial rotary transformer, a groove 502 is formed on the outer peripheral surface of a cylindrical ferrite core 501, and a winding 50 is formed in the groove 502.
3, and an outer core in which a groove 505 is formed on the inner peripheral surface of a cylindrical ferrite core 504 and a winding 506 is attached to the groove 505. are opposed to each other at a predetermined interval.

The cylindrical cores used in this coaxial rotary transformer are opposed to each other at a very small distance, for example 50 microns, and one side rotates at high speed, so the outer diameter, inner diameter, roundness, and coaxiality are Extremely high dimensional accuracy is required.

In the conventional manufacturing method of a cylindrical ferrite core for a coaxial rotary transformer, a method for grinding both axial end surfaces of a cylindrical ferrite core is as shown in FIG. 402 is arranged and fixed so that the axial direction of the cylindrical ferrite core 402 is perpendicular to the surface of the table 401.
The end face was ground by rotating the grinding diamond 403 toward the rotating part.

(Problems to be Solved by the Invention) According to the conventional method, the surface runout of the axial end face of the cylindrical ferrite core was approximately 1 to 20 microns, and had large variations.

Coaxial type rotary transformers are required to have extremely high precision as described above, and if surface runout occurs as described above, the cylindrical core will be fixed diagonally when glued to the cylinder with the end surface as a reference, and during high-speed rotation. However, when the outer core and inner core came into contact with each other, the gap between the cores changed and the characteristics of the rotary transformer became unstable.

In view of the above, an object of the present invention is to provide a method for manufacturing a coaxial rotary transformer with small surface runout.

(Means for Solving the Problems) The present invention provides a method for grinding both axial end surfaces of a cylindrical ferrite core used in a coaxial rotary transformer. Both end surfaces of the cylindrical ferrite core in the axial direction are simultaneously ground while the cylindrical ferrite core is arranged and fixed so as to be supported by the circumferential surface of the cylindrical ferrite core.

(Example) A schematic diagram of an example according to the present invention is shown in FIG. Further, FIG. 2 shows a sectional view taken along the line AA in FIG. 1, and FIG. 3 shows an enlarged view of the main parts. To explain this embodiment, a core holder 102 in which a plurality of V-shaped recesses 101 are formed, a grinding diamond 104, and a cylindrical ferrite core 103 are attached to the core holder 102.
The cylindrical ferrite core 103 is inserted into the core holder 102 at the C part, and the core holder 102 is rotated in the B direction, and the cylindrical ferrite core 103 is fixed by the fixing belt 105. was fixed to a core holder 102, and both end surfaces of the cylindrical ferrite core in the axial direction were simultaneously ground using a grinding diamond 104.

The surface runout of the cylindrical ferrite core according to this example was 1 to 5 microns, with little variation.

In this example, the outer peripheral surface of the cylindrical ferrite core was ground to have an outer diameter of 1 to 2 microns in roundness and cylindricity before both end faces were ground. The V-shaped concave portion, the attachment of the core holder to the rotating shaft, and the precision of the diamond are also set to high precision.

According to this embodiment, a highly accurate cylindrical ferrite core can be obtained, and the mass productivity is also excellent.

(Effects of the Invention) According to the present invention, it is possible to extremely improve the surface runout accuracy of the cylindrical ferrite core used in a coaxial rotary transformer, and it is also excellent in mass production. This makes it possible to reduce the price and is extremely useful industrially.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment according to the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is an enlarged view of the main part of the embodiment in FIG. FIG. 4 is a schematic diagram of a conventional example, and FIG. 5 is a sectional view of a coaxial rotary transformer. 101... V-shaped recess, 102... Core holder, 103... Cylindrical ferrite core, 104...
...Diamond for grinding, 105...Fixing belt.

Claims (1)

[Claims] 1 In a method of grinding both axial end surfaces of a cylindrical ferrite core used in a coaxial rotary transformer, the cylindrical ferrite core is placed in a core holder having a V-shaped core holder, and the periphery of the cylindrical ferrite core is The cylindrical ferrite core is arranged so as to be supported by a surface, and the cylindrical ferrite core is fixed in the position with a belt-like support, and in this state, both end surfaces of the cylindrical ferrite core in the axial direction are simultaneously ground. A method of manufacturing a coaxial rotary transformer.