JPS5833611B2 - Tape guide drum device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary head type magnetic recording/reproducing device (hereinafter referred to as a VTR).
This invention relates to a tape guide drum device for recording and reproducing video signals.

As is well known, in VTRs that use a rotating head, in the past, brushes and slip rings were used to transfer signals between the rotating part and the fixed part, but these did not have the shortcomings of longevity and noise. Contact rotary transformers came into use,
Rotary transformers are also cheaper than cylindrical types, which led to the adoption of flat-faced rotary transformers.

This rotary transformer is configured such that a rotating part that is connected to the rotating head and rotates together with the rotating part and a fixed part attached to the fixed side of the bearing or tape guide face each other in the plane direction and transmit signals. ing.

Planar facing type rotary transformers have functional and performance issues, such as deterioration of the degree of coupling and changes in the resonance frequency including the circuit system. There is a demand for the minimization of

In order to meet these demands, various mounting structures have been proposed in the past.

FIG. 1 shows a side sectional view of the main part of one example.

To explain this, the rotating part 1 is fixed to a fixed part 4 attached to a rotating disk 2 via a leaf spring 3 so as to face each other with a predetermined gap therebetween.

The gap between the rotating part 1 and the fixed part 4 is set by pushing the leaf spring 3 with three screws 5 screwed into the rotating disk 2 and moving the rotating part 1 downward in the axial direction. was.

However, in another conventional example shown in FIG. The gap between the rotary unit 6 and the titration unit 6 was adjusted so as to provide one titration shift.

However, in the method shown in FIG. 1, the gap adjustment is manual and requires a lot of adjustment time, and there is no way to know how the surface runout is occurring.

In addition, in the method shown in FIG. 2, the height dimensions in the axial direction that determine the gap between the rotating part 6 and the fixed part 100 are individually measured, the results are calculated, and the spacer 9 is selected, or a similar method is used. This requires a lot of time to determine the spacer.

When selecting the spacer 9 for the housing, there is also a drawback that the gap can only be set in stages because the types of spacer thicknesses are limited.

The present invention can eliminate such conventional drawbacks,
To provide a tape guide drum device which has a simple structure and can easily and reliably set the gap between a fixed part and a rotating part of a rotary transformer as desired.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 3 is a side sectional view of one embodiment of the present invention, FIG. 4 is a side sectional view of a rotating part in the same embodiment, and FIG. 5 is a side sectional view of a fixed part in the same embodiment.

In the embodiment shown in FIG. 3, an external rotary brushless DC motor section 32 equipped with an AC signal coupling type rotational position detection mechanism is directly connected to the shaft of the rotary head 30 to directly drive the rotary head.

This shows a so-called direct drive type tape guide drum device.

The motor section 32 will now be explained.

A bottomed cylindrical rotor portion 36 made of a magnetic material and directly connected to the main shaft 34 includes an annular permanent magnet rotor 38 and a short ring 40 for position detection. The portion 44 includes a stator 46 and a pair of position detection coils 47, which are formed from a laminated steel plate on which the drive winding 44 is provided.
It includes a position detection stator 48 made of an annular laminated steel plate which has been subjected to the following steps.

Next, the tape guide section 50 includes a cylindrical rotating drum 52 and a stationary drum 54.

The rotary drum 52 has a built-in rotary head 30 and rotates together with the rotary head 30. The rotary head 30 slightly protrudes from the outer cylinder of the rotary drum 52, and the magnetic tape is wound around the outer circumference of the drum. 56, or play back from it.

The rotating drum 52 is fixed to a rotating disk 58 press-fitted onto the main shaft 34 with a required number of screws 53, and rotates together with the main shaft 34.

The fixed drum 54 has a magnetic tape 56 diagonally arranged around its outer circumference.
The winding has a stepped part for guiding.

In the embodiment shown in FIG. 3, the bearing portion 60 that rotatably supports the main shaft 34 has a shape integral with the fixed drum 54, but the present invention is not limited to such a structure. , they may be separated individually and connected with screws or the like.

As shown in the figure, the bearing section 60 includes a housing 61, two ball bearings 62a and 62b, and their pole bearings 62.
A and 62b are provided with a pipe-shaped member 64 which is in contact with the end surfaces of the outer rings of these pole bearings and has an outer diameter that is approximately the same as the outer ring diameter of the ball bearing.

The pipe-shaped body 64 is fitted into a ball bearing hole 66 provided in the housing 61 so as to be movable in the axial direction, but when the final assembly is completed, two screws 68 are inserted from the side surface of the housing 61 in the radial direction. It is fixed by being attracted by.

The two ball bearings 62a, 62b are connected to the lower end surface of the rotating disk 58 that is integrated with the main shaft 34, and to the leaf spring 70. Uke is board 7
The two pawl bearings 62a are connected to each other by a preload boss 74 screwed to the main shaft 34 via a screw.

A preload is applied in the direction in which the inner ring of 62b approaches in the axial direction.

The rotary transformer 76 for transmitting signals to the rotary head 30 is of a plane facing type.
The flat rotating part 78 and the fixed part face each other in the axial direction.

The rotating portion 78 of the rotary transformer 76 is fixed to the seven-run surface 82 of the rotating disk 58 with screws 83, and rotates integrally with the rotating disk 58.

It should be noted that the coil wound around the rotating portion 78 is not necessarily connected to the rotating head 30.

As mentioned earlier, since the rotary disk 58 and the main shaft side are press-fitted together, for example, after they are integrated, the main shaft 3
It is possible to correct the surface runout by finishing the 7-run surface 82 based on the outer diameter of 4, and the rotary transformer 76 has both planar end surfaces ground to minimize parallelism. Since it can be finished, the surface runout of the rotating portion 78 after it is screwed can also be kept very small.

On the other hand, a fixed part 80 of the rotary transformer 75 is fixed to one end surface 84 of the fixed drum 54 side 9 with a screw 85, and faces the rotating part 78 in a plane.

The rotating portion 78 and the fixed portion 80 are assembled so as to have a predetermined gap.

Signals are taken out from the fixed part 80 through a terminal 86 connected to a coil wound around the fixed part 80.

The surface run-out of the fixing portion 80 relative to the main shaft 34 can be minimized by machining the ball bearing hole 66 and the one end surface 84 at the same time.

The structure of the embodiment of the present invention has been described above. Next, in order to make the effects of the present invention more clear, referring to FIGS. 4 to 6, the rotating part 78 of the rotary transformer 16 and A method of assembling the fixing part 80 so that the axial gap 1 is constant will be described.

In order to keep the gap constant, the rotating part 78 and the fixed part 80 are attached to respective holding members as shown in FIGS. 4 and 5.

That is, FIG. 4 shows a rotating unit 88, in which the rotating part 78 of the rotary transformer 76 is fixed with screws 83 to a rotating disk 58 into which the main shaft 34 is press-fitted.

Further, a ball bearing 62a, which is a component of a bearing, is already inserted into the main shaft 34 so as to be in contact with an end 58a of the rotating disk 58.

On the other hand, FIG. 5 shows a fixed side unit 90, in which a fixed portion 80 of the rotary transformer 76 is fixed to an end surface 84 of the fixed drum 54 with screws 85.

Further, a pipe-shaped body 64 is inserted into the housing 61,
It is temporarily fixed from the side with two screws 68.

As a result, the pipe-shaped body 64 is movable in the axial direction within a range outside the clearance of the escape hole 69 for inserting the screw 68.

Next, the procedure for assembling each unit prepared as shown in FIGS. 4 and 5 will be explained with reference to FIG. 6.

1. First, fix the rotating side unit 88 shown in FIG. 4 on the side opposite to the side on which the rotating section 78 of the rotary disk 58 is attached so that the rotating section 78 of the rotary transformer 76 is at the top. Place it on the table 92 of the ingredients.

Next, the tips of, for example, two strip-shaped spacers 94 made of polyester film or the like having a suitable length and having a thickness equal to the desired gap 1 are placed on the surface of the rotating portion 78 from both sides.

Thereafter, the fixed side unit 90 shown in FIG. 5 is inserted from above so that the surface of the fixed part 80 of the rotary transformer 76 faces the surface of the rotating part 78, and the axis is aligned with the rotating part 88. do.

When the fixed side unit 90 is inserted, first, the ball bearing 62a is inserted into the ball bearing hole 66 of the housing 61.
The outer ring of the fixed part 80 is fitted in, and the surface of the fixed part 80 sandwiches the spacer 94 and matches the surface of the rotating part 78 to be stopped.

Next, the other ball bearing 62b is inserted into the ball bearing hole 66 of the housing 61 along the main shaft 34.

The preparation of all the parts has been completed above, but the process of tampering with the temporarily fixed pipe-shaped body 64 will now be explained.

First, the fixed side unit 90 is held while applying a force W downward in the axial direction.

Due to this force W, the spacer 94 is held in close contact with the surfaces of the rotating part 78 and the fixed part 80.

Next, as shown in FIG. 6, on the outer ring end surface of the ball bearing 62b,
A load P equal to the preload load applied to the bearing is applied downward in the axial direction.

The load P is transmitted from the outer ring of the ball bearing 62b to the pin-shaped body 64, moves the pipe-shaped body 64 downward, reaches the outer ring of the ball bearing 62a, and the end surface of the inner ring of the ball bearing 62a is in contact with the rotating disk 58. From the fact, pole bearing 6
2a will be preloaded with a force P.

While maintaining this state, the pipe-like body 64 is inserted into the two screws 6.
At 8, it is permanently fixed to the housing 61.

That is, the pipe-shaped body 64 serves to determine the axial position of the pole bearing 62a.

After the 640 pipe-shaped bodies are fixed, if the forces P and W are completely removed, the clamping force between the rotating part 78 and the fixed part 800 of the spacer 94 is released, and the spacer 94 moves outward from the fixed drum 54. By pulling the other end of the spacer 94 that can be drawn out, the spacer 94 is attached to the rotating part 78.
and the fixed part 80.

Even after the spacer 94 is removed, the axial height position of the pole bearing 62a remains at a fixed level.
As shown in FIG. 1, the ball bearing 6 is
Preload P is added to 2a and 62b, and even after the bearing part is completed, the rotating part 78 and fixed part 8 of the rotary transformer 76
A gap of 0 can maintain a gap equal to the thickness of the spacer 94.

As is clear from the above description, the present invention has a structure in which the bearing portion that governs axial positioning is movable and adjustable in the longitudinal direction of the shaft in order to keep the gap of the planar rotary transformer constant. As long as a spacer equal to the desired gap i is used, the desired gap g can be easily and accurately obtained.

Moreover, by configuring each unit on the rotating side and fixed side as in the embodiment of the present invention described above, it is possible to easily minimize surface runout at the stage of each unit as a single unit, so that after assembling them, There is no need to worry about surface runout, and there is no need to carefully measure dimensions or prepare spacers for gap adjustment at each unit stage.

Furthermore, variations in the axial thickness of each component can be minimized.

As described above, according to the present invention, it is possible to significantly reduce the processing cost of parts and the cost of managing gaps, and it is possible to realize a high-performance tape guide drum device with good mass productivity and at low cost. There are some thick ones.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1 and 2 are side sectional views of main parts of a tape guide drum device equipped with a conventional plane-opposed rotary transformer, respectively, and FIG. 3 is a side sectional view of an embodiment of the present invention. Figure, 4th
5 and 5 are side sectional views of the rotary side and stationary side units, respectively, in the same embodiment, and FIG. 6 is a side sectional view of essential parts for explaining the assembly procedure of the same embodiment. 30...Rotating head, 32...Motor section, 34...Main shaft, 36...Rotor part, 44...Stator part , 50...
Tape guide section, 52...Rotating drum, 54.
...Fixed drum, 58 ... Rotating disk, 60 ... Bearing section, 61 ... Housing, 62a, 62b ... Pole bearing, 64・・・
... Pipe-shaped body, 68 ... Screw, 69 ...
...Escape hole for screw insertion, 70...Flat spring, 72...Brace is plate, 74...Preload boss, 76...Rotary Rotating part of transformer, 8
0... Fixed part of rotary transformer, 88...
...Rotating side unit, 90... Fixed side unit, 94... Spacer.

Claims (1)

[Scope of Claims] 1. A bearing part that rotatably supports a main shaft rotationally driven by a motor, a tape guide part including a rotating drum and a fixed drum around which a tape can be wrapped around and guided for traveling; A rotating part and a fixed part are provided on the rotating drum side and the fixed drum side facing each other with a required gap in the length direction of the main shaft so as to act as a signal between the rotating head and the fixed part. A tape guide drum device comprising a rotary transformer having a rotating disk supporting the rotating drum and having a rotating part of the rotary transformer attached thereto, and a ball bearing constituting the bearing part on the main shaft. a housing which is combined to form a rotating unit and into which the main shaft and the ball bearing can be fitted into the fixed drum to which the fixed portion of the rotary transformer is attached so as to be movable in the longitudinal direction of the main shaft; and the main shaft. a pipe-shaped body that is inserted through the housing and movably disposed in the housing in the longitudinal direction of the main shaft to restrict the downward movement of the ball bearing; and a fixing means that allows the pipe-shaped body to be fixed to the housing. A tape guide drum device characterized in that a fixed side unit is constructed by coupling bearing parts including the above, and the rotating side unit and the fixed side unit are detachably coupled. 2. The tape guide drum according to claim 1, wherein an inner ring of the ball bearing is fixed to the main shaft, and an outer ring is supported in contact with the upper end of the pipe-shaped body. Device. 3. In claim 2, the bearing section is arranged within the housing so that the outer ring can abut against the lower end of the pipe-shaped body, and the inner ring is arranged in the housing through an elastic member. A tape guide drum device characterized in that it includes another ball bearing whose bearing is fixed to a preload boss fixed to a main shaft.