JPH03194704A - Rotary magnetic head drum - Google Patents

Abstract

PURPOSE:To prevent a change in the spacing between a stator and a rotor by the expansion or contraction of the layer of an adhesive agent with a temp. change and the consequent inclination of the stator by press fitting and fixing the stator to the plane on the outer periphery of the cylinder at the center of a lower drum by means of a flange in the edge part of a nut to be screwed onto the outer periphery of the cylinder which supports the shaft at the center of the lower drum. CONSTITUTION:The outer periphery 2a in the upper part of the cylinder 2-1 provided at the center of the lower drum 2 for supporting a shaft 3 is threaded and the collar 10a is provided on the upper side of the lower drum 2 on the outer side of the cylinder 2-1. The stator 4a is placed in the prescribed position of the plane on the upper side of the lower drum 2 on the outer side of the cylinder 2-1. The top end of the stator 4a is pressed downward by the collar 10a and is fixed to the plane on the upper side of the lower drum 2 when the nut 10 is screwed to the outer periphery 2a in the upper part of the cylinder 2-1. The stator 4a is, therefore, surely fixed when a washer consisting of an elastic body is interposed in the upper or lower part of the stator and the nut 10 is tightened. The inclination of the stator occurring in the expansion or contraction of the adhesive agent with the temp. change is prevented.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a rotary magnetic head drum used in equipment such as a video tape recorder, and particularly to the installation of a rotary transformer provided on the outer periphery of a shaft used in the drum. It is related to.

(Prior Art) FIG. 2 is a sectional view of an example of a rotating magnetic head drum used in a video tape recorder.

The lower drum 2, which does not rotate, has a cylinder 2-1 at its center, and ball bearings 7 and 7b are shrink-fitted on the upper and lower sides of the cylinder 2-1, and the shaft 3 is attached to a pole bearing 7a.
and 7b. A disk S is shrink-fitted to the upper part of the shaft 3, and a rotating upper drum 1 having a shape as shown in the figure is fixed to the upper surface of the disk S. shaft 3
A preload collar 8 is inserted below to apply preload to the bearing, and the preload collar 8 is fixed to the shaft 3 by a set screw 9. A cylindrical cavity is formed inside the upper drum l, and a rotor 4b of a rotary transformer is mounted on the inner wall of the cavity.
However, a holder 11 provided at the edge thereof is fixedly attached to the upper drum 1 by means of a screw 13 via a leaf spring 12.

The stator 4a of the rotary transformer is coated with an anaerobic adhesive on the upper surface of the flat pedestal 15 on the outer circumference of the cylinder 2-1 of the lower drum 20 so that the stator 4a of the rotary transformer surrounds the outside of the cylinder 2-1 and faces the rotor 4b. It is fixed by adhesive. This bonding method is performed as follows.

First, a curing accelerator is applied to the bottom surface of the stator 4a, an adhesive is applied to the upper surface of the lower drum 20 and the pedestal 15, and both are overlapped and held under pressure for 1 to 2 minutes, thereby bonding them together.

The upper drum 1 and the rotor 4b can be fixed using an adhesive in the same way as the lower drum 2 and the stark 41 are fixed, but the structure shown in FIG. 2 as described above is often used. The rotor 4bKFi molded holder 11 is fixed in advance with adhesive, this holder 11 is held down by a ring-shaped leaf spring 12, and is fixed to the upper drum 1 with a plurality of screws 13, so it is easier to work than with adhesive. is much better. A required number of magnetic heads 6 are attached to the lower surface of the upper drum 1. Although not shown, a magnet is fixed to the upper drum 1, and the upper drum 1 is rotated by generating a rotating magnetic field in the stator of a motor provided on the lower drum 2 so as to face the magnet.

(Problems to be Solved by the Invention) As mentioned above, conventionally, when fixing the stator 4a of the rotating transformer to the lower drum 2, adhesive is used, so compared to fixing the rotor 4b to the upper drum 1, , requires extra effort and time.

Further, since an adhesive is interposed between the stator 4a and the lower drum 20 pedestal 15, the adhesive layer expands or contracts due to temperature changes, causing the stator 4a to tilt and the rotor 4
Since the distance between the magnetic head 6 and the magnetic head 6 changes, an adverse effect occurs when the signal picked up by the magnetic head 6 is transmitted to the outside.

(Means for Solving the Problem) The starter was fixed to the flat surface of the outer periphery of the cylinder at the center of the lower drum by a collar on the edge of a nut that was screwed into the outer periphery of the cylinder that supported the shaft at the center of the lower drum.

(Function) With the above structure, the stator can be fixed to the lower drum without using adhesive by screwing the nut into the cylinder.

(Example) Figure g1 is a schematic cross-sectional view of one embodiment of the present invention.

The same parts as in the conventional example in the K2 diagram are represented by the same reference numerals.

The difference from the conventional example shown in Fig. g2 is the structure in which the stator 4 of the rotary transformer is fixed to the lower drum. The upper outer periphery 2a of the cylinder 2-1 provided at the center of the lower drum 2 for supporting the shaft 3 is threaded, and a collar 10a is provided at the upper end of the nut 10 that is screwed into the cylinder 2-1. It is being The stator 4a is attached to the lower drum 2 outside the cylinder 2-1.
Place the nut 10 in a predetermined position on the upper plane of the cylinder 2.
When screwed into the screw on the outer periphery 2a of the upper part of
The upper end of a is pressed downward by the collar 10a and fixed to the upper plane of the lower drum 2. An elastic washer is interposed on the upper or lower part of the stator 4a,
It can be securely fixed by tightening 1G.

(Effects of the Invention) According to the present invention, since no adhesive is used, the process of assembling the lower drum and the stator is shortened, and even after completion, the stator may be damaged due to expansion or contraction of the adhesive due to temperature changes. Prevents tilting and stabilizes the performance of rotary transformers.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of an embodiment of the present invention, and FIG. 2 is a schematic sectional view of a conventional example. 1... Upper drum, 2... Lower drum, 3... Shaft, 4a... Stator, 4b... Rotor, 5... Disk, 6.5... Magnetic head, 71t7b... Ball bearing , 10... nut

Claims (1)

[Claims] 1. A rotary transformer that has a cylinder provided in the center of the lower drum and has a thread on the top, and a nut having a flange that is screwed into the cylinder, and the nut is screwed into the cylinder and the rotary transformer is installed on the outer periphery of the cylinder. A rotating magnetic head drum with a stator pressed against the upper surface of the lower drum by a collar.