JPS6023767Y2 - Video head cylinder device - Google Patents

Description

[Detailed description of the invention] This invention is an invention for improving the video head cylinder device of a magnetic recording/reproducing device, and its purpose is to reduce the vibration of the outer peripheral surface (tape guide surface) of the rotating cylinder during rotation. To provide a video head cylinder device in which operations such as assembling the rotating cylinder and replacing the video head can be performed with high precision and without adjustment (one-touch) by having a structure that can be kept to a minimum. be.

A conventional video head cylinder device to which the present invention is improved will be explained with reference to FIG.

Due to the running characteristics of the magnetic tape, the video head cylinder device is generally divided into two parts: a rotating cylinder to which the video head is attached, and a fixed cylinder.

In FIG. 1, 1 is a fixed cylinder having a tape guiding end surface 2 on its outer peripheral surface, 3 is a rotating cylinder having a shaft hole 4 concentric with the guiding end surface 2 at its center, and a video head 5 is attached to the lower part of the periphery with screws 6. It is installed by

Reference numeral 7 denotes a rotating shaft integrally having a rotating disk 8, which is rotatably held in the fixed cylinder 1 by a bearing 9. Its fitting shaft 10 is inserted into the shaft hole 4 of the rotating cylinder 3, and the rotating cylinder 3 is Rotating disk 8 with screw 11
is fixed.

By the way, in the above structure, the alignment between the outer circumferential end surface 12 of the rotating cylinder 3 and the guide end surface 2 of the fixed cylinder 1 is determined by the fitting of the fitting shaft 10 into the shaft hole 4, and if there is any deviation in this alignment, the above-mentioned problem will occur. Since the outer circumferential end surface 12 wobbles, and this wobble appears as jitter on the recording/playback screen, the fitting shaft 10 and shaft hole 4 require extremely precise mechanical finishing and dimensional control. This is the cause of high product costs.

Furthermore, with the recent downsizing of equipment, the diameter of the cylinder has become smaller, and the precision adjustment of the fitting shaft 10 and shaft hole 4 has reached its limit. The method used is to measure the deflection with a dial gauge or the like and then adjust and fix the deflection.

However, this method has the disadvantage that it requires a measuring instrument and advanced technology when replacing the video head, that is, when replacing the rotary cylinder 3, and requires a long time for adjustment.

The present invention is intended to provide a video head cylinder device that does not have the above-mentioned drawbacks, and consists of a rotary cylinder with a video head attached to its outer periphery, and a fixed cylinder with a magnetic tape guide end surface provided on its outer periphery. In a structure in which the rotating cylinder is fixed to a rotating disk that is rotatably held by the fixed cylinder, an upwardly opening tapered hole is provided at the center of the rotating cylinder and is concentric with the outer peripheral end surface of the rotating cylinder. , a fitting shaft provided at the center of the rotating disk is inserted into the tapered hole, a center hole into which the fitting shaft is inserted, and a plurality of balls provided at regular intervals around the center hole. A positioning cylinder that rotatably holds a ball in each chamber is inserted into and fixed to the fitting shaft, and the plurality of balls abuts the tapered hole and the fitting shaft, thereby fixing the fixed cylinder of the rotary cylinder. It is characterized in that positioning is performed for.

The embodiment will be described below with reference to FIGS. 2 and 3.

21 is a fixed cylinder having a tape guide end surface 22 on its outer circumferential surface, 23 is a rotating cylinder having a video head 24 at the lower part of its periphery, and a tapered hole 2 opening upward in the center thereof.
5 is a provision.

26 is a rotating disk, and its rotating shaft 27 is a bearing 2.
8, it is rotatably supported by the fixed cylinder 21.

Reference numeral 30 denotes a position regulating cylinder installed in the tapered hole 25, which has a center hole 31 into which the fitting shaft 29 of the rotary disk 26 is inserted, and three ball chambers 33 holding balls 32 around the periphery, which are arranged at an angle of 120°.
They are set at intervals of .

When this positioning cylinder 30 is fitted into the fitting shaft 29 protruding from the tapered hole 25 and the head of the fitting shaft 29 is tightened with the screw 34 via the washer 35, the ball 32 is moved to the slope of the tapered hole 25 and the fitting shaft 29. The rotating cylinder 23, the rotating disk 26, and the position regulating tube 30 are integrally fixed by contacting the rotating cylinder 23, the rotating disk 26, and the position regulating cylinder 30.

36 is a retaining ring for removing the washer 35, and 37 is a screw hole for the screw 34.

Next, its operation will be explained with reference to FIG.

If the three balls 32 have the same diameter, the ball 32 and the fitting shaft 2
9 and the contact point P2 between the ball 32 and the tapered hole 25.
The distance MA between them is always constant.

Therefore, if the height H of the ball 32 is constant, the taper hole 25
and the fitting shaft 29 are kept concentric regardless of their diameters.

That is, the outer peripheral end surface 38 of the rotating cylinder 23 and the fitting shaft 29
are kept concentric, but when a difference of ΔH occurs in the height H of the ball 32, the positional deviation B□-B2 between the fitting shaft 29 and the rotating cylinder 23 reduces the taper of the tapered hole 25 by 1/x. given that,
B, -82=4H/2X.

Since the ball 32 is regulated by the lower end surface of the position regulating tube 30, this BI B2, that is, ΔH, is due to the looseness of the fitting shaft 29 of the position regulating tube 30 with respect to the fitting shaft 29.
This is caused by the slope of 9.

The inclination of this fitting shaft 29 is y1, the length of fitting is z1, fitting axis 2
If the diameter of the sphere 9 is D and the diameter of the sphere 32 is d, then ΔH#y/z (D+d) is obtained.

Therefore, based on ΔH < BI B2 is BI B2 #
It can be expressed as y(D+d)/2-□,
1/x = 1150, y = 0.05mm,
z=10mm, D=6mm, d=4mm and lever, Bs B2=O,0005mm'j, (Le.

The positional deviation of the Shitakatch fitting shaft 29 with respect to the rotating cylinder 23 can be kept within 1 micron at worst.

Incidentally, since the sphericity of the sphere 32 has an accuracy within 0.3 microns of variation, there is almost no influence.

As described above, the cylinder device of the present invention has a plurality of (three) ball chambers 3 arranged at a constant interval (120°).
A plurality of (3) balls rotatably held by a position regulating cylinder 30 having
The rotating cylinder 23 is positioned relative to the fixed cylinder 21 by contact with the fixed cylinder 21. Therefore, if the deflection during rotation of the fitting shaft 29 and the concentricity of the outer peripheral end surface 38 of the rotating cylinder 23 and the tapered hole 25 are controlled, the rotation can be controlled. The deflection of the outer peripheral end surface 38 due to the rotation of the cylinder 23 can be reduced to a negligible extent, and when assembling the device or replacing the video head (rotating cylinder), one-touch adjustment is required without using a measuring device. Moreover, it enables highly accurate assembly.

Note that because the rotating cylinder 23 is often made of aluminum based material due to the running characteristics of the magnetic tape, the wall surface of the tapered hole 25 may be dented or damaged by the pressure of the ball 32, and during long-term use. It is conceivable that the accuracy will decrease.

In order to prevent this, it is effective to construct the tapered portion 39 having the tapered hole 25 from a hard material, such as stainless steel, as shown in FIG.

[Brief explanation of the drawing]

Figure 1: Longitudinal cross-sectional view of a conventional video head cylinder device.
Figure 2 is a vertical cross-sectional view of the video head cylinder device of the two inventions, and Figure 3 is an exploded view of the main parts of the two inventions, where A is a screw, washer, and retaining ring, and the mouth is a vertical cross-sectional view of the positioning tube. , C is a plan view of the same, 2 is a side view of the same, E is a partial sectional view of the rotating cylinder, and 6 is a partial sectional view of the rotating disk. Fig. 4: An explanatory diagram of the operation of the present invention, and Fig. 5: A diagram showing another embodiment of the rotary cylinder of the present invention. 21... Fixed cylinder, 22... Guide end surface, 23... Rotating cylinder, 24...
・Video head, 25... Taper hole, 26...
... Rotating disk, 27 ... Rotating shaft, 28
...Bearing, 29...Mating shaft, 3
0...Position regulating tube, 31...Center hole,
32... Ball, 33... Ball chamber, 34...
...screw, 35...washer, 36...
...Removal retaining ring, 37...Screw hole, 3
8...Outer peripheral end surface, 39...Taber portion.

Claims (2)

[Scope of utility model registration request] (1) Consisting of a rotating cylinder with a video head attached to its outer periphery and a fixed cylinder with a magnetic tape guide end surface on its outer periphery, the rotating cylinder is fixed to a rotating disk rotatably held by the fixed cylinder. In the structure, an upwardly opening tapered hole is provided at the center of the rotating cylinder and is concentric with the outer peripheral end surface of the rotating cylinder, and a fitting shaft provided at the center of the rotating disk is inserted into the tapered hole, and the fitting shaft is inserted into the tapered hole. A center hole into which the shaft is inserted, and a plurality of ball chambers provided at regular intervals around the center hole, each of which has a positioning cylinder that rotatably holds the ball, is inserted into the fitting shaft and fixed. The video head cylinder device is characterized in that the rotating cylinder is positioned relative to the fixed cylinder by the plurality of balls coming into contact with the tapered hole and the fitting shaft. (2) The video head cylinder device according to claim 1, wherein the tapered portion having the tapered hole is made of a hard material such as stainless steel.