JPS6190316A - Rotary head cylinder - Google Patents

Abstract

PURPOSE:To simplify a construction and an assembly and to realize highly accurate rotation by installing outer wheels made into one with a shaft in a housing and press-fixing the top part of the outer wheel. CONSTITUTION:A rotary cylinder 10 fixed with the video head 12 is fixed to the shaft 16 and driven and rotated by a motor 26. The outer wheels 20a and 20b are held freely and rotably by means of balls 18a and 18b is two; upper and lower grooves of the shaft 16, and in the midway thereof a preloaded spring 24 is provided to eliminate a play. The outer wheel 20a is engaged in the housing 14 and its top is press-fixed by means of a cap 22. For this reason, the construction and assembly can be greatly simplified without using a conventional adhesion-fixing method. Furthermore, the height change of the head 12 becomes small and highly accurate rotation can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotating head cylinder that can be used in a video tape recorder.

Conventional configuration and its problems In recent years, video tape recorders have been required to be smaller and lighter.

The rotary head cylinder used in conventional video tape recorders has a ball bearing fixed to the housing with adhesive.

However, adhesive fixing not only requires a troublesome process of adhesion, but also lacks reliability. Another problem is that once assembled, it is impossible to disassemble.

OBJECTS OF THE INVENTION An object of the present invention is to provide a rotating henoton cylinder that is simple in construction and highly accurate.

Structure of the Invention The rotary head cylinder of the present invention includes a shaft that rotatably supports a magnetic head for recording/reproducing video signals on a magnetic tape, and a groove provided in two positions above and below in the axial direction of the shaft. , an outer ring rotatably held via a plurality of balls, a spring located between the two outer rings for pressing the two outer rings in the axial direction of the shaft and applying preload, and holding the outer ring. a housing for
The outer ring is provided with a cap for press-fixing the aperture surface of the outer ring to the housing, and is configured such that one both end surfaces of the outer ring are held between the housing and the cap to hold the shirt collar. This allows easy assembly and high precision.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The figure shows a cross-sectional view of a rotating heel cylinder according to an embodiment of the present invention. In the figure, 10 is a rotating cylinder, 12 is a video head, 14 is a housing, 16 is a shaft, and 18&.

18b is a bearing ball, 20a, 20bi-j.

22 is a cap, 24 is a preload spring, and 26 is a motor.

A rotating cylinder 1Q to which a video head 12 is fixed is rotatably supported by a shaft 16, and a motor 2
Rotationally driven at 6. The shaft 16 has grooves on its outer periphery at two locations, upper and lower in the axial direction, and balls 18a, 18b.
Two upper and lower outer rings 20a and 20b are rotatably held via the upper and lower outer rings 20a and 20b.

The preload spring 24 presses vertically between the two outer rings 20iL and 2ob, and presses the shaft 16 and the outer ring 20a.

This offsets the play with 20b.

The two outer rings 20 & 20b are fitted into the housing 14 which is integrated with the fixed cylinder, and the upper end of the upper outer ring 20a is pressed by the cap 22 and fixed. This allows the video head 12 to move into the housing 14.
It can be rotated while maintaining a constant height. Additionally, the housing 14 and shaft 16 expand and contract when subjected to changes in ambient temperature. However, since there is a difference in the coefficient of thermal expansion between the two, it is necessary to absorb the elongation. To explain this in detail, as the ambient temperature increases, the housing 14 and shaft 16 expand in the directions of arrows A and B.
The distance between the outer rings 202L and 20b also increases.

However, the amount of elongation of the housing 14 is greater than the amount of elongation of the shaft 16.
, the housing 14 moves in the direction of arrow B relative to the lower outer ring 20b. At this time, the outer ring 20b due to the fitting between the outer ring 20b and the housing 14
The sliding force F in the directions of arrows A and B is applied to the upper and lower outer rings 20&,
Since it is added to the preload of the preload spring 20b, if the spring pressure of the preload spring 24 is -6p, the preload Y between the outer rings 20& and 2Ob becomes Y=P10F. Also, when the ambient temperature drops,
Since the housing 14 moves in the direction of the arrow with respect to the lower (+11) outer ring 20b, the preload Y becomes y=p-F.

Here, when the fitting between the housing 14 and the lower outer ring 20b is tight, and the sliding force F is greater than the spring pressure P of the preload spring 24, the preload Y becomes extremely large when the ambient temperature rises, causing a load on the bearing. Not only does this increase the load, but also rotational unevenness increases. Also, if the ambient temperature is low, the preload y==p-
In the formula for F, the value of Y is 0 or negative. This is a state where no preload is applied, and the balls 182L, 1
A gap is created between the outer ring 20 & 20b and the shaft 16 via the outer ring 8b, and the video head 12 cannot rotate while drawing an accurate trajectory.

However, in the present invention, the above c? Since the fitting between the ring 14 and the lower outer ring 20b is made loose to make the sliding force F in the directions of arrows A and B smaller than the spring pressure P of the preload spring 24, the increase in bearing load when the temperature rises is small and the temperature can be maintained at low temperatures. Even at times, the preload will never be less than ○. i ft The upper outer ring 20 nearer to the video head 12 a 'i When fixed with the mecap 2, the height of the video head 12 due to the difference in elongation between the housing 14 and the shaft 16 due to changes in ambient temperature. A high-performance rotary head cylinder with very little change can be obtained.

Effects of the Invention As is clear from the above explanation, the present invention is not only easy to assemble, but also easy to assemble, since the outer ring integrated with the shaft is attached to the housing and fixed by pressing with a cap. By making the force required for sliding between the housing and the outer ring smaller than the spring pressure of the preload spring, there is no increase in preload force or loss of preload due to changes in ambient temperature, and by fixing the outer ring near the video head, The effect is that the height of the video head is less likely to change.

[Brief explanation of the drawing]

The figure is a sectional view of a rotary head cylinder according to an embodiment of the present invention. 14... Housing, 16... Shaft, 1sa, 18b... Ball, 202L, 2
0b... Outer ring, 22... Cap, 2
4...Preload spring.

Claims (2)

[Claims] (1) A shaft that rotatably supports a magnetic head for recording/reproducing video signals on a magnetic tape, and a plurality of balls that rotate through grooves provided in two places above and below in the axial direction of the shaft. an outer ring that is freely held; a spring that is located between the two outer rings and presses the two outer rings in the axial direction of the shaft to apply a preload; a housing that holds the outer ring; A rotary head cylinder comprising a cap for press-fixing an end face to the housing, and configured such that both end faces of one of the outer rings are held between the housing and the cap to hold the shaft. . (2) The cap is attached to the housing at a position that fixes the outer ring closer to the magnetic head, and the other outer ring and the housing are configured to be movable in the axial direction of the shaft,
The rotating head cylinder according to claim 1, wherein the force required to move the outer ring and the housing in the axial direction is smaller than the pressing force of a spring applying preload between the two outer rings. .