JPH0973601A - Rotary magnetic head device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the respective gaps between a printed circuit board and a magnet and between this printed circuit board and a back yoke uniform by mounting and fixing the printed circuit board to the mounting boss on the back yoke side. SOLUTION: The printed circuit board 8 is held by a positioning boss 9 on the side of the magnet 62 fitted to a supporting shaft 1 and the mounting boss 92 on the back yoke 7 side and is adhered and fixed to the mounting boss 92. The mounting boss 92 is formed larger than the positioning boss 9 in the length in the axial direction of the part tightly fitted to the supporting shaft. The mounting boss 92 fixed with the printed circuit board 8 at its end face is longer in the axial direction than the positioning boss 9 and, therefore, the mounting accuracy at the time of fitting to the supporting shaft is higher and the degree of inclination with the supporting shaft induced by press fitting or shrinkage fitting of the positioning boss 9 is negligible. Then, the gaps between the printed circuit board 8 and the magnet 62 and between the printed circuit board 8 and the back yoke 7 are respectively kept uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a VTR integrated with a camera.
Etc. to a rotary magnetic head device with a built-in motor.

[0002]

2. Description of the Related Art Ultra-compact rotary magnetic head devices for conventional camera-integrated VTRs and the like are required to be compact and lightweight.
The one with a built-in D motor is the mainstream. FIG.
It is a conventional rotary magnetic head device with a built-in DD motor,
The rotary drum (5) is rotatably arranged on the support shaft (1) projecting from the shaft center of the fixed drum (2) through the bearings (41) (41) and the support cylinder (4). ) Is equipped with a magnetic head (51).

A fixed coil member (31) provided on the fixed drum (2) and a rotating coil member (32) provided on the support cylinder (4).
Are arranged close to each other to form a rotary transformer (3). The DD motor (6) includes an annular magnet (6) arranged concentrically with the rotary drum (5) via a rotary yoke (61).
2) Supporting the rotary drum (5) between the back yoke (7), which is an annular magnetic material fixed to the drum, and the magnet (62) and the back yoke (7) with a minute gap therebetween. It is constituted by a printed circuit board (8) fixedly arranged on the shaft (1).

The printed circuit board (8) has a drive coil, a rotation detection coil and a position detection coil formed in three layers, and the magnet (62) has one or more pairs of magnetic poles.

[0005]

The gap between the back yoke (7) and the printed circuit board (8) and the gap between the printed circuit board (8) and the magnet (62) must be uniform. However, since the printed circuit board (8) is fixed by fixing the screw (91) on the positioning boss (9) which is shrink-fitted or press-fitted into the supporting shaft (1), the positioning boss (9) is fixed to the supporting shaft (1). ), The printed circuit board (8) also tilts with respect to the support shaft (1), between the printed circuit board (8) and the back yoke (7), and between the printed circuit board (8) and the magnet ( In the extreme case, the outer circumference of the printed circuit board (8) may be the back yoke (7) or the magnet (62).
May come into contact with.

If the axial length of the positioning boss (9) is increased, the positioning boss (9) can be attached with sufficient accuracy so that the inclination with respect to the support shaft (1) can be neglected. Since the distance between the magnet (62) and the magnet (62) becomes large and the lengthened length is disadvantageous for press-fitting or shrink fitting, it is not carried out. The present invention provides a rotary magnetic head device that can solve the above problems.

[0007]

In the rotary magnetic head device of the present invention, a rotary drum (5) having a magnetic head (51) and a fixed drum (2) are arranged on a support shaft (1), and the rotary drum (5) ) And a magnet (62) having a pair of magnetic poles or a plurality of pairs of magnetic poles between the back yoke (7) of an annular magnetic body that rotates together with the rotating drum (5) and rotating integrally with the rotating drum (5). , FG for frequency power generation
In a rotary magnetic head device in which a coil, a PG coil for generating a phase detection signal and a driving coil are laminated in three layers and a printed board (8) fixed on a support shaft (1) is arranged with a minute gap, Printed circuit board (8) has support shaft (1)
The mounting boss (9) is sandwiched between the magnet (62) side positioning boss (9) and the back yoke (7) side mounting boss (92).
The mounting boss (92) fixed to 2) by adhesion, caulking or the like has a larger axial length in the portion tightly fitted to the shaft than in the positioning boss (9).

[0008]

[Operation and effect] The positioning boss (9) on the side of the magnet (62) fixes the printed circuit board (8) directly by only positioning the printed circuit board (8) in the axial direction with respect to the magnet (62). Therefore, the degree of inclination of the positioning boss (9) with respect to the support shaft (1) caused by press fitting or shrink fitting does not pose a problem. Since the mounting boss (92) having the printed circuit board (8) fixed to the end face is longer in the axial direction than the positioning boss (9), the mounting accuracy when fitted to the support shaft (1) is high, and the printed circuit board (8) is ), The magnet (62), and the gap between the printed circuit board (8) and the printed circuit board (8) can be kept uniform.

Increasing the length of the positioning boss (9) in the axial direction makes it impossible to increase the space between the magnet (62) and the printed circuit board (8) and press fit or shrink fit. As in the present invention, the mounting boss (92) having the printed circuit board (8) fixed to the end face and the printed circuit board (8) positioning boss
By increasing the axial length of the positioning boss (9) by fitting it to the support shaft (1) on the (9) side and projecting it outward from the hole of the annular back yoke (7). The trouble has disappeared.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a portion above a rotary drum (5) of a rotary magnetic head device of the present invention, and FIG. 2 shows a portion above a rotary yoke (61). Since the configuration is the same as that of the conventional example of FIG. 3, the configuration not described in the following description is as described in FIG. Support shaft
A space between a rotary drum (5) mounted on (1) via a bearing (41) and a support cylinder (4) and an annular back yoke (7) mounted on the rotary drum (5). In addition, the DD motor (6) is configured.

The DD motor (6) has an annular magnet (62) arranged coaxially with the rotary drum (5) via a rotary yoke (61) and a rotary drum (5) coaxial with the drum. In the space between the back yoke (7) and the magnet (62) fixed to the back yoke (7), there is a small gap between them and the supporting shaft.
(1) It is constituted by a printed circuit board (8) fixedly arranged on the above. A drive coil, a rotation detection coil, and a position detection coil (none of which are shown) are formed in three layers on the printed circuit board (8), and the magnet (62) has one or more pairs of magnetic poles. .

A feature of the present invention resides in the mounting structure of the printed circuit board (8). The printed circuit board (8) has a positioning boss (9) on the side of the magnet (62) fitted to the support shaft (1) and a back. yoke
It is sandwiched between the mounting boss (92) on the (7) side and the mounting boss (92).
It is glued and fixed to. The positioning boss (9) is a support shaft
It is fixed to (1) by press fitting or shrink fitting. Mounting boss (9
2) is tightly fitted to the support shaft (1) without rattling, and the follow set screw (95) is screwed into the through screw hole (94) opened in the peripheral surface to the support shaft (1). Fixed.

A thin short tube portion is formed on the inner edge of the mounting boss (92) on the inner end side.
(93) is provided in a protruding manner, and the tubular portion is fitted in the central hole of the printed board (8). The printed circuit board (8) can be fixed to the mounting boss (92) by extending the thin short tubular portion (93) and caulking the tubular portion (93). Mounting boss (92) is the positioning boss
The length in the axial direction of the portion tightly fitted to the shaft is larger than that in (9).

However, the positioning boss (9) on the side of the magnet (62)
Does not fix the printed circuit board (8) directly, only by positioning the printed circuit board (8) in the axial direction with respect to the magnet (62). Therefore, by press fitting or shrink fitting the positioning boss (9). In the degree of inclination with respect to the resulting support axis (1),
It doesn't matter. Since the mounting boss (92) having the printed circuit board (8) fixed to the end face is longer in the axial direction than the positioning boss (9), the mounting accuracy when fitted to the support shaft (1) is high,
The gaps between the printed circuit board (8) and the magnet (62) and between the printed circuit board (8) and the printed circuit board (8) can be kept uniform.

It is impossible to increase the axial length of the positioning boss (9) because the distance between the magnet (62) and the printed circuit board (8) becomes large. The mounting boss (92) having the printed circuit board (8) fixed to it is fitted to the support shaft (1) with the printed circuit board (8) facing the positioning boss (9), whereby the axial direction of the positioning boss (9). The positioning boss (9) to the annular back yoke (7) even if the length of the
It can be projected to the outside from the hole of the and does not hinder. The present invention is not limited to the configuration of the above embodiment, and various modifications are possible within the scope of the claims.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of the present invention.

FIG. 2 is a cross-sectional view of an essential part in which a positioning boss is tilted.

FIG. 3 is a cross-sectional view of a conventional rotary head device.

FIG. 4 is a cross-sectional view showing a state in which the above positioning boss is inclined.

[Explanation of symbols]

 (1) Support shaft (2) Fixed drum (5) Rotating drum (6) DD motor (7) Back yoke (8) Printed circuit board (9) Positioning boss

Claims (1)

[Claims] 1. A rotary drum (5) having a magnetic head (51).
And the fixed drum (2) is provided on the support shaft (1), and the back yoke (7) of an annular magnetic body rotates integrally with the rotating drum (5).
(62) that has one or more pairs of magnetic poles between the rotary drum (5) and the rotary drum (5) and rotates integrally with the rotary drum (5), an FG coil for frequency power generation, and a PG coil for phase detection signal power generation In the rotary magnetic head device in which the driving coil is laminated in three layers and the printed board (8) fixed on the support shaft (1) is arranged with a minute gap, the printed board (8) is
Positioning boss (9) on the side of the magnet (62) fitted to the support shaft (1)
And the mounting boss (92) on the back yoke (7) side, the mounting boss (92) is attached to the mounting boss (92) and fixed by caulking, etc. A rotary magnetic head device characterized in that a tightly fitted portion has a large axial length.