JPS6356604B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a rotary head device of a rotary head type magnetic recording/reproducing apparatus.

In recent years, rotating head type magnetic recording and reproducing devices (VTR)
As video cameras become smaller and smaller, portable VCRs are beginning to become popular. Along with this, rotating head devices have been made smaller and thinner, but conventional devices are approaching their structural limits. FIG. 1 shows a conventional rotary head device. A rotating shaft 2 is arranged at the center of the fixed lower drum 1, and the rotating shaft 2 is rotatably attached to the fixed lower drum 1 by bearings 3 and 4.
The rotating upper drum 5 facing the fixed lower drum 1 is attached to a support member 6 by a mounting screw 7, and the supporting member 6 is fixed to the rotating shaft 2 above the bearing 3 by a mounting screw 8. As a result, the rotating upper drum 5 is rotatably arranged relative to the fixed lower drum 1. At least one head substrate 10 having a magnetic head 9 is attached to the rotating upper drum 5 with attachment screws 11. The outer peripheral surfaces of the rotating upper drum 5 and the fixed lower drum 1 serve as running surfaces for the magnetic tape.
The rotating side winding 1 of the rotary transformer is mounted on the support member 6.
A rotary transformer stationary winding 13 is attached to the fixed lower drum 1 opposite to this, and the rotating winding 12 is connected to the magnetic head 9 to receive signals input to the magnetic head 9 or Signals output from the magnetic head 9 are input/output via electromagnetic coupling of a rotary transformer.

A support member 14 is attached to the rotating shaft 2 below the bearing 4, and a rotary yoke 16 of a motor 15 is attached to the support member 14 with a mounting screw 17. A rotary magnet 18 is fixed to the rotary yoke 16. Opposing the rotary magnet 18, a stator 19 and a stator coil 20
is fixed to the fixed lower drum 1.

In the conventional rotating head device shown in FIG. 1, since the upper rotating drum 5 is attached to the rotating shaft 2 and the rotating shaft 2 is supported by the bearings 3 and 4, 4, the inclination of the rotating shaft 2 due to the relative positional deviation between the bearings 3 and 4 will have a large effect on the rotation locus of the magnetic head 9, making it difficult to obtain high-precision rotation. Therefore, it has been extremely difficult to make the rotary head device thinner in the axial direction. In addition, the rotation accuracy of the rotating upper drum 5 is as follows:
The rotational accuracy of the rotating shaft 2, the support member 6, and the rotating upper drum 5 is added, and a great deal of cost is incurred in maintaining the individual accuracy of each component and the fitting accuracy between the components.

Conventionally, a ball bearing was formed between the head disk and the fixed drum in order to make it thinner.
However, since the motor for rotational drive is provided on the outer diameter side of the ball bearing,
It is not possible to increase the diameter of the ball bearing, so even slight unevenness in the depth of the ball retaining groove of the ball bearing or the diameter of the balls will greatly affect the surface runout of the head disk and improve rotation accuracy. It is difficult to do so.

The object of the present invention is to solve the above-mentioned problems, reduce the axial dimension and make it thin,
It is an object of the present invention to provide a rotating head device that can reduce the number of parts, reduce costs, and reduce surface runout of rotating members caused by bearings.

In order to achieve this object, the present invention provides at least one annular groove in a portion near the outer periphery of an end face perpendicular to the rotation center of a rotating member having a magnetic head, and an end face of a stationary drum facing the annular groove. An annular groove is provided in the annular groove, a plurality of rolling members are inserted between the annular grooves, a rolling bearing is formed between the rotating member and the fixed drum, and the rotational drive unit is positioned on the inner diameter side of the rolling bearing. The rolling bearing is characterized in that the diameter of the rolling bearing is increased.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 2 shows an embodiment in which the present invention is applied to an upper drum rotation system. A rotating upper drum 22 is arranged opposite to the fixed lower drum 21, and both drums 21, 22
The outer peripheral surface becomes the tape running surface. Rotating upper drum 2
An annular groove 25 is provided in a portion near the outer periphery of an end surface 24 perpendicular to the rotation center 23 of the drum 2, and an annular groove 27 is provided in an end surface 26 of the fixed lower drum 21 facing the annular groove 25. A plurality of steel balls 28 are inserted between the annular grooves 25 and 27. A rolling bearing 29 is formed by the annular grooves 25 and 27 and the steel ball 28. Fixed lower drum 21
The stationary side winding 30 of the rotary transformer for signal transmission, the rotating side winding 31, the stator coil 32 of the motor, the rotary magnet 33, and the rotating upper drum 2 are disposed on the opposing end surfaces of the rotary upper drum 22.
A preload magnet 34 and a preload adjustment screw 35 are attached for holding the bearing 2 and adjusting the preload of the rolling bearing 29. A head base plate 37 having a magnetic head 36 is attached to the rotating upper drum 22 by attachment screws 38.

By adjusting the screwing degree of the preload adjustment screw 35, the preload magnet 34 and the preload adjustment screw 35 can be adjusted.
The suction force between the rotating upper drum 22 and the steel balls 28 of the rolling bearing 29 is adjusted.
Adjustment of the preload applied to the device is performed in a non-contact manner.

When the stator coil 32 is energized from a drive circuit (not shown), a rotational force acts on the rotary magnet 33, and the rotating upper drum 22 is rotated while being supported by the rolling bearing 29 above the fixed lower drum 21. A magnetic tape (not shown) is wound around the outer peripheral surfaces of the fixed lower drum 21 and the rotating upper drum 22 and runs, and a magnetic head 36 rotates and scans the magnetic surface of the magnetic tape at a rotational speed faster than the running speed of the magnetic tape. Recording or playback is performed by doing this.

Signals transmitted and received between the magnetic head 36 and the magnetic tape are input from or output to the signal processing circuit via the rotating winding 31 and stationary winding 30 of the rotary transformer.

According to this embodiment, since the rolling bearing 29 is provided between the drums 21 and 22 in a plane perpendicular to the rotation center 23 of the rotating upper drum 22, a significant reduction in thickness can be achieved. Furthermore, since there are no members corresponding to the rotating shaft 2 and support member 6 shown in FIG. 1, the number of parts can be reduced and costs can be reduced. Furthermore, since the rolling bearing 29 is provided near the outer periphery of both drums 21 and 22, and the stator coil 32 and rotary magnet 33 are located on the inner diameter side of the rolling bearing 29, the diameter of the rolling bearing 29 becomes larger. Therefore, it is possible to reduce the degree of influence on the surface runout of the rotating upper drum 22 due to unevenness in the depths of the annular grooves 25 and 27 and the diameter of the steel balls 28.

The preload adjustment of the bearings 3 and 4 in FIG.
When fixing the stator coil 20 to the rotating shaft 2,
A complicated method is used, such as fixing using the load current flowing through the support member 6 as an index, or fixing by placing a weight equivalent to the preload on the support member 6. In contrast, according to the present embodiment, the preload can be adjusted freely by adjusting the screwing degree of the preload adjustment screw 35, and moreover, the preload can be adjusted while the rotating upper drum 22 is held above the fixed lower drum 21. Therefore, preload adjustment costs can be reduced. At the same time, in the conventional type shown in FIG. 1, if the temperature expansion coefficient of the rotating shaft 2 is smaller than the temperature expansion coefficient of the fixed lower drum 1, there is a risk that the preload of the bearings 3 and 4 will be lost due to the temperature drop. However, in this embodiment, preloading is performed without contact, so there is no fear of preload loss.

Further, according to this embodiment, the rotating upper drum 22 is the only rotating member, and the mounting surface of the head board 37 and the mounting surface of the rotating side winding 31 of the rotary transformer can be made the same surface. , accuracy can be easily maintained and costs can be reduced.

In this embodiment, the rotating upper drum 22 corresponds to the rotating member of the present invention, and the steel balls 28 correspond to the rolling member.

FIG. 3 shows details of the rolling bearing 29. A shield wall 39 is installed on the fixed lower drum 21 near the steel balls 28.
is attached to the rotating upper drum 2 facing it.
A shield groove 40 is provided at position 2, and the shield wall 39 enters the shield groove 40. This shields the grease in the rolling bearing 29 and prevents dirt from entering the rolling bearing 29 from the surroundings.

In addition, as shown in FIG. 4, the shield groove 4
0, the shield wall 39 is connected to the rotating upper drum 2.
Alternatively, as shown in FIG. 5, another shield wall 41 overlapping the shield wall 39 may be attached to the end surface 24 of the rotating upper drum 22. You can.

FIG. 6 shows another embodiment in which the present invention is applied to an intermediate drum rotation system. Components similar to those in FIG. 2 are designated by the same reference numerals. The fixed upper drum 42 has a connecting member 43
The lower drum 21 is fixed by the mounting screws 44 and 45.
Fixed. An intermediate drum 46 corresponding to the rotating member of the present invention is arranged between the fixed upper drum 42 and the fixed lower drum 21. A rotating wheel member 48 that is perpendicular to the rotation center 23 of the intermediate drum 46 and has an end surface on the same plane as the end surface 47 facing the fixed lower drum 21 is attached to a position near the outer periphery of the intermediate drum 46. An annular groove 49 on the end face of
will be provided. A fixed ring member 50 is attached to the fixed lower drum 21 opposite to the rotating ring member 48,
An annular groove portion 51 is provided on the end surface of the fixed ring member 50. A plurality of steel balls 5 are provided between the annular grooves 49 and 51.
2 is inserted. Rotating ring member 48, fixed ring member 5
0 and the steel balls 52 form a rolling bearing 53. The annular grooves 49, 51 may be provided directly on the intermediate drum 46 and the fixed lower drum 21 as in the embodiment shown in FIG.

The operation and effects of this embodiment are almost the same as those of the embodiment shown in FIG.

FIG. 7 shows another embodiment in which the present invention is applied to a head bar rotation system. Components similar to those in FIGS. 2 and 6 are designated by the same reference numerals. A head bar 54, which corresponds to the rotating member of the present invention, is arranged between the fixed upper drum 42 and the fixed lower drum 21. An annular groove 56 is provided in a portion near the outer periphery of an end surface 55 perpendicular to the rotation center 23 of the head bar 54, and the end surface 26 of the fixed lower drum 21 facing the annular groove 56
An annular groove portion 27 is provided in the annular groove portion 56,
A plurality of steel balls 28 are inserted between 27. Both annular grooves 56 and 27 and the steel ball 28 form a rolling bearing 57
form.

The operation and effects of this embodiment are almost the same as those of the embodiment of FIG. 2 or 6.

FIG. 8 shows another embodiment of the present invention in which the upper drum is rotated and the circumferentially opposed drive is used. Components similar to those in FIG. 2 are designated by the same reference numerals. A stator coil 32 and a rotary magnet 33 of the motor are attached to opposing circumferential surfaces of the fixed lower drum 21 and the rotating upper drum 22, respectively, and face each other. In this embodiment, the rotary magnet 33 also serves as a preload magnet.

Rolling bearings 29, 53, 57 are steel balls 28, 5
A roller may be inserted instead of 2. Further, the number of rolling bearings 29, 53, 57 is not limited to one, but two or more may be provided.

The preload magnet 34 may also be used as the rotary magnet 33 as shown in FIG. 8, or if the stator coil 32 has an iron core, the iron core may also be used as the preload magnet. You may also do so. Instead of the preload adjustment screw 35, other magnetic material, such as the preload magnet 3
4 may be annular ones that face each other around the entire circumference.

As explained above, according to the present invention, since the rolling bearing is formed between the end face of the rotating member perpendicular to the rotation center of the rotating member and the end face of the stationary drum, the axial dimension can be reduced and the thickness can be reduced. It can be shaped. Furthermore, since the conventional rotating shaft and support member can be omitted, the number of parts can be reduced and costs can be reduced. Furthermore, since the rolling bearing was installed closer to the outer periphery between the rotating member and the stationary drum, and the rotational drive unit was located radially inward from the rolling bearing, the diameter of the rolling bearing became larger, which caused problems caused by the bearing. The surface runout of the rotating member can be reduced.

[Brief explanation of drawings]

Figure 1 is a sectional view of a conventional rotary head device;
The figure is a cross-sectional view of an embodiment of the present invention, and FIG. 3 is a cross-sectional view of an example of a rolling bearing according to an embodiment of the present invention.
Figure 4 is a cross-sectional view of another example of a rolling bearing.
Figure 5 is a cross-sectional view of another example of a rolling bearing.
FIG. 6 is a sectional view of another embodiment of the invention, FIG. 7 is a sectional view of another embodiment of the invention, and FIG. 8 is a sectional view of another embodiment of the invention. 21... Fixed drum, 22... Rotating upper drum,
23... Center of rotation, 24... End face, 25... Annular groove, 26... End face, 27... Annular groove, 28...
... Steel ball, 29 ... Rolling bearing, 32 ... Stator coil, 33 ... Rotary magnet, 36 ...
... Magnetic head, 46 ... Intermediate drum, 47 ... End surface, 49 ... Annular groove, 51 ... Annular groove, 52
... Steel ball, 53 ... Rolling bearing, 54 ... Head bar, 55 ... End face, 56 ... Annular groove, 57
...Rolling bearing.

Claims (1)

[Claims] 1 a fixed drum; a rotating member having a magnetic head and rotatably disposed opposite to the fixed drum;
In a rotary head device equipped with a rotary drive unit that drives a rotary member, at least one annular groove is provided in a portion near the outer periphery of an end face perpendicular to the rotation center of the rotary member, and a fixed drum facing the annular groove is provided with at least one annular groove. An annular groove is provided in the end face, and a plurality of rolling members are inserted between the two annular grooves to form a rolling bearing between the rotating member and the fixed drum,
A rotary head device characterized in that the rotary drive section is located on the inner diameter side of the rolling bearing.