JPH01227251A - Positioning mechanism for rotary drum - Google Patents

Abstract

PURPOSE:To fit a helical lead and a magnetic head at a prescribed interval by fixing two types of rotary drums whose heights from the reference face of the helical lead of a lower drum are different by a fitting machine screw provided separately for a drum base. CONSTITUTION:A lower drum fitting part 1d provided coaxially with a tape running face 1a of a lower drum 1 is fitted into a fitting hole 11a provided at the center of the slope fitting face of a drum base 11 with a minute clearance. Next, a reference hole 1c whose diameter corresponds to the difference in the height of a lead 1b in the prescribed positions of the rotary drum in which a helical lead 1b and a reference face 1e of the drum 1 are processed in a single body and the rotary drum in which the lead 1b and the face 1e are processed with a rotation axis 5 as a reference, and a positioning pin 12 on the base 11 are provided. The pin is fitted into the hole 1c and rotated in a prescribed direction and fitted to the base 11. Thus, the helical lead and the magnetic head can be stably fitted at the prescribed interval.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is applicable to VTR (video tape recorder) and R-DAT.
(rotary digital audio tape recorder, ro
tarry digital audiotaperec
The present invention relates to a positioning mechanism for a rotating drum of a helical scan type magnetic recording/reproducing device such as a magnetic recording/reproducing device such as a magnetic recording/reproducing device using a helical scan method.

<Summary of the Invention> In a mechanism for positioning a rotating drum with respect to a drum base in order to mount the rotating drum diagonally with respect to a chassis, the slanted surface provided on the drum pace is perpendicular to the slanted surface in order to mount the rotating drum diagonally with respect to the chassis. The inner diameter of the drum mounting part provided on the rotary drum and the outer diameter of the lower drum mounting part coaxially with the outer diameter of the tape running surface of the lower drum of the rotating drum fit together with a small gap, so that the lower drum and The position of the drum pace is determined by the helical lead of the lower drum and the lower drum reference surface which is the reference when attaching the rotating drum to the drum pace. Machining the helical lead of the lower drum with a diameter corresponding to the difference in height of the helical lead at a predetermined position between the helical lead and the rotating drum, which is machined based on the rotating shaft fixed to the lower drum reference surface. A pin with the same radius and a diameter corresponding to the height difference of the helical lead is provided on the drum pace, and this pin is aligned with the reference hole of the lower drum to connect the helical lead of the lower drum and the height of the helical lead. The lower drum reference surface is machined as a single lower drum.The rotary drum has a predetermined direction (CW force direction K in the drawing, and the helical lead of the lower drum and the lower drum reference surface are referenced to the rotating shaft fixed to the lower drum. By rotating and pressing the machined rotary drum in a predetermined direction (CCW direction in the drawing) with the CW force direction being opposite, the helical lead of the lower drum and the lower drum reference surface are connected to the lower drum as a single unit. A rotary drum with a helical lead of a certain height at a predetermined position that has been machined, a helical lead of the lower drum, and a helical lead of the lower drum that has been machined with the lower drum reference surface as a reference relative to the rotating shaft fixed to the lower drum. Helical IJ of a rotating drum in which the drum reference surface is processed in the state of the lower drum alone
- By fixing both of the rotating drums, which have a helical lead of a certain height lower than the certain height at the predetermined position of the drum plate, to the drum plate of the same shape with separately provided lower drum mounting screws, the drum plate On the other hand, it is possible to hold the lower drum at a constant height at a predetermined position of the helical lead of the lower drum.

<Conventional technology> An embodiment of the prior art is shown in FIGS. 7 and 8.

FIG. 7 shows a schematic cross-sectional view of the rotating drum.

In FIG. 7, 1 is the lower drum and this tape running surface 1a
A helical lead 1b for guiding the tape is machined on. A magnetic head 3 for magnetically recording and reproducing signals is attached to the 1F ram 2 with a predetermined precision.
This upper drum 3 is attached to a rotating shaft 5 via a support called a disk 4. Rotation axis 5 in this figure
This is called a bearing with a shaft, and an inner ring groove 5c is machined into the shaft 5d, and the bearing outer rings 5a, 5b are integrated with the shaft 5d. Regarding this shaft 5d, the shaft 5d and the inner ring groove 5c may be completely separate. Further, the rotating shaft 5 is fixed to the lower drum 1 so as to be concentric with the tape running surface 1a of the lower drum 1. Furthermore, a collar 8 is fixed to the rotating shaft 5 with screws or the like, and a drum motor rotor 10 is attached to the collar 8.

A drum motor stator 9 is attached to the lower drum 1, and a drum motor rotor 10 is rotated by supplying current from a drive circuit (not shown). Further, the rotating drum is fixed to a drum pace 11 and attached to the chassis 13 via the drum pace 11 at an angle of a predetermined angle. In the above explanation, a step called a helical lead 1b for guiding the tape is machined on the tape running surface 1a of the lower drum l, so that the helical lead 1b and the magnetic head 3 are spaced at a predetermined distance. need to be maintained. FIG. 8 is a diagram (schematic diagram in the plane direction) showing only the positioning part of the lower drum 1. A tape running surface 1a of the lower drum 1 is provided with an edge lead ib for guiding the tape. This helical lead 1b is processed so that it maintains a constant height at a predetermined position when the lower drum 1 is attached to the drum base IIK.
Helical lead 1 provided at any location on the lower drum 1
Chucking surface 1 based on the reference hole IC for machining b
d is chucked and processed. Also drum pace 11
There is a lower drum mounting hole 11a provided at the center of the lower drum mounting surface so as to fit with this lower drum mounting portion 1d with a gap, and there is a gap between this lower drum mounting hole 11a and the surface of the lower drum mounting portion 1d. They are fitted and positioned. In addition, the positioning pin 12 provided on the drum base 11 with the same radius hK as the reference hole 1c for machining the helical lead 1b of the lower drum for positioning in the rotational direction is
The side diameter is slightly smaller and it fits with a gap. Also, from this state, for example, move the lower drum l in a predetermined direction (CW
By rotating the lower drum 1 in the force direction and then attaching it to the drum base 11, the lower drum 1 is fixedly attached to the drum base 1IVc.

<Problems to be Solved by the Invention> In the rotating drum as described above, it is necessary to maintain a predetermined distance between the helical lead of the lower drum and the magnetic head. Therefore, in the prior art described above, the height of the helical lead of the lower drum at a predetermined position must always be constant. For example, the rotating shaft 5 fixed to the lower drum IK
Helical lead 1b and drum pace 11 based on
When using a rotary drum with a lower drum reference surface 1e that is processed as a reference when attaching the lower drum 1 to the helical lead 1b and the lower drum, all rotary drums have a rotating shaft 5 fixed to the lower drum 1 as a reference. The reference surface 1e must be processed so that the helical +7- dot 1b of the lower drum 1 and the magnetic head 3 are spaced at a predetermined distance.

In order to solve the above problems, the lower drum mounting hole of the drum pace is fitted with a small clearance to the mounting part of the lower drum, which is provided coaxially with the outer diameter of the tape running surface of the lower drum. The center position of the lower drum can be adjusted by fitting them together, and the helical lead of the lower drum and the lower drum reference surface can be machined on the lower drum alone to adjust the position in the rotational direction. The diameter of the lower drum corresponds to the difference in the height of the helical lead at a predetermined position between the drum and the rotating drum, which is machined with the helical lead of the lower drum and the lower drum reference surface based on the rotating shaft fixed to the lower drum. A reference hole for helical lead processing and a positioning pin having a diameter corresponding to the height difference of the helical lead are provided on the same radius as the reference hole on the lower drum mounting surface of the drum base,
This positioning pin is fitted into the reference hole, and the helical lead of the lower drum and the lower drum reference surface are machined in the state of the lower drum alone. Both rotary drums are machined using the rotating shaft fixed to the lower drum as a reference, and both rotating drums are pressed in the CCW direction, which is opposite to the CW force direction.

The lower drum can always be stably attached to the drum base so that the helical lead of the lower drum and the magnetic head are at a predetermined distance.

By using the above means, the helical lead of the lower drum and the lower drum reference surface can be placed at a predetermined position on the lower drum like a rotating drum machined with the rotating shaft fixed to the lower drum as a reference. Even for a rotating drum with a lower height, the helical lead of the lower drum and the magnetic spatula F are mounted on the same drum base as the rotating drum in which the helical lead of the lower drum and the lower drum reference surface are processed in the state of the lower drum alone. It is possible to always stably install the parts so that the distance between them is maintained.

<Embodiment> An embodiment of the present invention is shown in FIGS. 1, 2, 3, 4, 5, and 6.

FIG. 1 shows an outline of a sectional view of a rotating drum. In Fig. 1, l is the lower drum, and this tape running surface 1
A has a helical lead 1b for guiding the tape.
is being processed. A magnetic head 8 for magnetically recording and reproducing signals is attached to the upper drum 2 with a predetermined precision, and the upper drum 2 is attached to a rotating shaft 5 via a support called a disk 4. The rotating shaft 5 in the figure of Jin is called a bearing with a shaft, and the inner ring groove 5c is connected to the shaft 5d.
The bearing outer rings 5a and 5b are integrally formed with the shaft 5d. Regarding this shaft 5d, the shaft 5d and the inner ring shaft 5
c may be completely different. Further, the rotating shaft 5 is fixed to the lower drum IK so that it is concentric with the tape running surface 1aIc of the lower drum 1. Further, 6 and 7 are a rotary transformer rotor and a stator, which transmit signals sent and received to the magnetic head 3 to the circuit side, and record electrical signals from the circuit side onto a tape via the magnetic head 3. . Furthermore, a collar 8 is fixed to the rotating shaft 5 with screws, etc.
A drum motor rotor 10 is attached to the collar 8. Further, a drum motor stator 9 is attached to the lower drum 1, and current is supplied by a drive circuit (not shown) to rotate the drum motor rotor 10. Also,
The rotating drum is fixed to a drum pace 11VC, and is attached to the chassis 13 via the drum base 11 at an angle of a predetermined angle. In the above description, it is necessary to maintain the lower drum 1 such that the helical lead 1b for guiding the tape and the magnetic head 3 are separated by a predetermined distance. FIG. 2 is a diagram (schematic diagram in the plane direction) showing only the positioning part of the lower drum 1. In FIG. 2, a helical lead 1b for guiding the tape is formed on the outer peripheral surface 1a of the lower drum 1. This heri cal lead 1
b is when the lower drum l is attached to the drum base 11,
Since the hemline lead 1b is processed to maintain a constant height at a predetermined position, the hemline lead 1b is provided at any location on the lower drum 1.
The chucking surface 1d is based on the reference hole 1c for machining.
is chucked and processed. Also, drum base 11
There is a lower drum mounting hole 11a provided at the center of the mechanical drum mounting surface that fits with this lower drum mounting portion 1d with a gap, and this lower drum mounting hole 11a and the lower drum mounting portion 1
The surface d is positioned with a clearance fit. In addition, for positioning in the rotational direction, the reference hole 1c for machining the lower drum edge cal lead 1b and the positioning pin 12 provided on the same radius on the drum base 11 are arranged such that the pin side diameter is the same as that of the reference hole 1c. It is smaller than the diameter and is a clearance fit. Further, from this state, the lower drum 1 is attached to the drum base 11 by rotating the lower drum 1 in the CW force direction shown in FIG. 2 and then fixing it to the drum base. FIG. 3 shows the lower drum 1 shown in FIG. 1 attached to the drum base 11 with reference to the rotating shaft 5 fixed to the lower drum 1 so as to be flush with the tape running surface 1a of the lower drum 1. This figure schematically shows a cross-sectional view of a rotary drum in which a lower drum reference surface 1e, which serves as a reference for attachment, and a helical lead 1b processed into the tape running surface 1a of the lower drum 1 are processed. As mentioned above, the lower drum 14 shown in this figure is obtained by processing the helical lead 1b and the lower drum reference surface 1e of the lower drum l shown in FIG. The height from the lower drum reference surface 14c is lower than the height of the helical lead 1b from the lower drum reference surface 1e at a predetermined position on the lower drum 1. FIG. 4 is a diagram (schematic diagram in the plane direction) showing only the positioning portion of the lower drum 14. The helical leads 1b and 14b must be maintained at a predetermined distance from the magnetic head 3. Therefore, in order to correct the above-mentioned height difference, the lower drum 14 is rotated in the CCW direction as shown in FIG. 4, contrary to the rotation direction of the lower drum 1 in FIG. It is installed. Figure 5 shows the lower drum 1 on the right half.
, an outline of the lower drum of the lower drum 14 is shown in the left half.

FIG. 6 is a diagram (schematic diagram in the plane direction) showing only the positioning portions of the lower drums 1 and 14. The height of the helical lead 1b from the lower drum reference surface 1e at a predetermined position of the lower drum 1 is indicated by yl. The lower drum 14 is machined by processing the lower drum reference surface 1e of the lower drum 1 by an amount indicated by xl and the helical lead 1b by an amount indicated by x2, with the rotation axis 5 as a reference. The height of the helical lead 14b from the lower drum reference surface 14e at a predetermined position is the height indicated by y2. In order to make the height indicated by y2 the same as the height indicated by yl of the lower drum l, the lower drum 14 is rotated by the angle indicated by 10 in the direction of the arrow in FIGS. 5 and 6.

φD in FIG. 5 is the diameter of the outer peripheral surface 1a (14a is the same) of the lower drum.

Further, θ is the angle formed between the helical lead 1b (14b) and the lower drum reference surface 1e (14e). r in Fig. 6 is the distance from the center of the reference hole "C+14c" for machining the helical leads 1b, 14b of the lower drums 1, 14 from the center of the lower drum.The reference holes 1c and 14c have the same diameter. Reference numeral 12 denotes a pin for positioning the rotating drum in the rotational direction, which is provided on the drum mounting surface of the drum pace (not shown).The center of this positioning pin 12 is the center of the drum mounting surface of the drum pace (not shown). It is located at a distance indicated by r from the center of the lower drum mounting hole 11a provided in the lower drum mounting hole 11a.Although Δθ in FIG. 6 and Δθ in FIG.
The rotation angle of θ is determined by the reference hole “C+14c”.
and the diameter φdl of the pin 12 on the drum pace.

The diameter difference between φd2 and φdl is φd2-φdt = z
It is expressed as r(yt-Y2)/φD--θ. 1st
Reference hole 1c for machining the helical lead of the lower drum of the rotating drum assembly shown in FIGS. 2, 3, and 4.

The lower drum 1
Helical lead 1b from lower drum reference surfaces 1e, 14e at predetermined positions.

Rotating drums 14b having different heights can be stably attached to the same drum pace.

<Effects of the Invention> With the above-described configuration, the rotating drum positioning mechanism of the present invention allows two types of rotating drums with different heights from the lower drum reference surface of the helical lead of the lower drum to be attached to the same drum pace. It becomes possible. Therefore, for example, the process of machining the helical lead and lower drum reference surface of the lower drum using the rotating shaft fixed to the lower drum as a reference may be performed on a rotating drum with poor precision in the helical lead shape or the lower drum reference surface, or on the lower drum. This can only be done for rotating drums where the lower drum swings relative to the rotating shaft when the shaft is fixed. Then, it becomes possible to stably feed the rotating drums subjected to the above-described processing and the rotating drums not subjected to the processing at the same drum pace.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing one embodiment of the rotating drum positioning mechanism of the present invention, FIG. 2 is a schematic plan view showing only the positioning section of the lower drum of the rotating drum in FIG. 1, and FIG. Fig. 1 is a sectional view of the grinder after processing the helical lead and lower drum reference surface, Fig. 4 is a schematic plan view showing only the positioning part of the lower drum of the rotary drum in Fig. 3, and Fig. 5 is the same as Fig. 3. 6 is a schematic plan view showing only the positioning section of the lower drum of the rotating drum in FIG. 5, and FIG. 7 is an implementation of a conventional positioning mechanism for the rotating drum. FIG. 8 is a schematic cross-sectional view showing an example, and FIG. 8 is a schematic plan view showing only the positioning portion of the lower drum of the rotating drum in FIG. 7. In the drawing, 1 is the lower drum, la is the tape running surface, 1b is the helical lead, 1c is the reference hole, 1d is the lower drum attachment part,
1e is a lower drum reference surface, 2 is an upper drum, 8 is a magnetic head, 4 is a disk, S is a rotating shaft, 5a, 5b are bearing outer rings, 6 is a rotary transformer rotor, 7 is a rotary transformer stator, 8 is a collar, 9 is drum motor stator, l. Hatram motor rotor, 11 is drum pace, 11
a is the lower drum mounting hole, 12 is the positioning pin, 13 is the chassis, 14 is the lower drum, 14a is the tape running surface, 14
b indicates a helical lead, 14c indicates a reference hole, 14d indicates a lower drum mounting portion, and 14e indicates a lower drum reference surface. Agent Patent Attorney Takeshi Sugiyama (and 1 other person) Figure 1 Figure 3 Figure 5 Figure 6 Figure 7 W48 Ward

Claims (1)

[Claims] 1. A helical scan type magnetic recording and reproducing device in which the magnetic head rotates and records and plays diagonally on a magnetic tape.The upper drum (2) and lower drum (1) are integrated by a rotating shaft (5) into a chassis. It has a drum base (11) for mounting diagonally to the drum base (13), and the inner diameter of the lower drum mounting hole (11a) provided on the slope of this drum base (11) perpendicular to the slope, and Lower drum (1)
The outer diameter of the tape running surface (1a) and the outer diameter of the lower drum attachment part (1d) provided coaxially fit with each other with a minute gap, and the lower drum (1) has an oblique angle for tape running. The drum base (11) is provided with a positioning pin (12) having a diameter smaller than that of the reference hole (1c), which is located on the same radius as the reference hole (1c) used for positioning for processing the helical lead (1b) which is a step. In a rotating drum having a positioning mechanism, the helical lead (1b) of the lower drum (1)
The lower drum reference surface (1e), which is used as a reference when attaching the rotating drum to the drum base (11), is machined from the lower drum (1) alone, and the helical lead (1b) of the lower drum (1). Corresponds to the height difference of the helical lead (1b) at a predetermined position between the lower drum reference surface (1e) and the rotating drum which is machined based on the rotating shaft (5) fixed to the lower drum (1). The reference hole (1
c) and the locating pin (12) on the drum base (11)
A rotating drum positioning mechanism characterized by being provided with.