JPH05250605A - Method for assembling head drum of magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To confine the height from the reference plane of a stationary cylinder to a magnetic head within a permissible range by working the height from the bearing butt surface of a rotating cylinder to a magnetic head mounting surface according to the height from the reference plane of the stationary cylinder to the upper surface of the bearing. CONSTITUTION:The height from the reference plane 21 of the stationary cylinder 2 to the end face of the bearing 5 with which the rotating cylinder 1 comes into contact is H1 and the height from a stationary rotary transformer 9 to the end face of the bearing 5 is G1. The mounting surfaces 13 and 14 are adjusted and machined to adjust the height H2 from the bearing butt surface 12 of the rotating cylinder 1 to the magnetic head mounting surface 13 with respect to the bearing 5 and the height G2 from the bearing butt surface 12 to the rotating rotary transformer mounting surface 14. The rotating cylinder 1 and the magnetic head 7 are thereafter mounted and the rotating cylinder 1 and the stationary cylinder 2 are assembled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a VTR (video tape recorder) and a DAT (digital audio tape recorder).
The present invention relates to a method for assembling a head drum for magnetic recording / reproducing.

[0002]

2. Description of the Related Art In a head drum of this kind, in order to efficiently transmit an electric signal, as shown in FIG. 5, a fixed rotary transformer (9) and a rotary rotary transformer (8) are connected. Gap G ₀ within a certain range, for example 40
It is necessary to assemble so that it fits within ~ 60μm.

As one of the methods, as shown in FIG. 5, a flywheel in which a rotary rotary transformer (8) is fixed.
Spacer between the bearing abutment surface (31) of (3) and the bearing (5)
(6) is inserted, and the effects of the thickness variation of the rotary transformers (8) and (9), the thickness error of the bearing (5), and the machining error of the fixed cylinder (2) are between the rotary transformers (8) and (9). The gap G ₀ does not appear in the variation.

Further, in consideration of the compatibility of the head drum, the magnetic head is moved from the lower reference surface (21) of the fixed cylinder (2).
The error of height H ₀ up to (7) is within a certain range, for example, 50 μm.
It is necessary to make the following, and further, it is necessary to combine so that the outer peripheral tape sliding contact surface (11) of the rotating cylinder (1) is concentric with the rotating shaft (4).

Therefore, after assembling the flywheel (3) by setting the gap G ₀ between the rotary transformers (8) and (9), the flywheel (3) is moved from the reference surface (21) of the fixed cylinder (2) to the rotary cylinder.
(1) Make sure that the height H ₃ of the mounting surface (61) is constant, and that the fitting part between the rotary cylinder (1) and the flywheel (3) is the rotary shaft.
After cutting the fitting portion so as to be concentric with (4), the rotary cylinder (1) is fitted into the flywheel (3) and fixed with screws (10).

The head drum having the above structure has a gap G ₀ between the rotary transformers 8 and 9 and a fixed cylinder reference surface 21.
From the magnetic head to the magnetic head (7) H ₀ , rotating cylinder (1)
Although it is possible to secure all concentricity of the tape sliding contact surface (11) with respect to the rotating shaft (4), there is a drawback that the number of parts increases.

Further, as shown in FIG. 1, if the rotary shaft (4) is simply press-fitted and fixed directly to the rotary cylinder (1) and the flywheel (3) is omitted, the number of parts is reduced, but the rotary gap G ₀ between the transformer (8) (9), stationary cylinder
In order to secure the height H ₀ from the reference surface (21) to the magnetic head (7) in (2), a high processing precision is required for each component individually, and the yield is deteriorated.

According to the present invention, the number of parts is reduced and the accuracy of the parts is not increased, but the gap between the rotary transformers is set within an allowable error, and the mounting height error of the magnetic head from the reference plane is reduced. The purpose of this study is to clarify a method for assembling a head drum that can fit within a certain range.

[0009]

In the head drum of the present invention, the rotary shaft (4) penetrates the shaft center of the fixed cylinder (2) through the bearing (5), and the advancing end of the rotary shaft (4) rotates. The cylinder (1) is directly fitted and fixed in the hole (18) of the shaft center, and the rotary cylinder (1) and the fixed cylinder (2) are respectively equipped with rotary rotary transformers (8).
The fixed rotary transformer (9) and the fixed rotary transformer (9) are arranged opposite to each other with a clearance within the allowable range, and the rotary cylinder (1) has a magnetic head.
A method for assembling a head drum having (7), comprising: a height H ₁ from a reference surface (21) of a fixed cylinder (2) to an end surface of a bearing (5) against which a rotating cylinder (1) abuts; Depending on the height G ₁ from the transformer (9) to the end surface of the bearing (5), from the bearing abutting surface (12) of the rotating cylinder (1) to the bearing (5) to the magnetic head mounting surface (13). Magnetic head mounting surface to adjust height H ₂ and height G ₂ from bearing abutment surface (12) to rotary rotary transformer mounting surface (14)
(13) After adjusting and cutting the rotary rotary transformer mounting surface (14), the rotary cylinder (1) and the magnetic head (7) are mounted, and then the rotary cylinder (1) and the fixed cylinder (2) are assembled.

In another invention, the height H ₂ from the bearing abutting surface (12) of the rotary cylinder (1) to the magnetic head mounting surface (13) and the bearing abutting surface ( Instead of processing the magnetic head mounting surface (13) and the rotary rotary transformer mounting surface (14) of the rotary cylinder (1) in order to adjust the height G ₂ from the 12) to the rotary rotary transformer mounting surface (14), a spacer is used. It is characterized by interposing.

Still another aspect of the present invention is that from the bearing abutting surface (12) of the rotary cylinder (1) to the bearing (5) to the magnetic head mounting surface.
Up (13) the height H _2, and the height G ₂ from the bearing contacting surfaces (12) to rotate the rotary transformer attachment surface (14) instead of adjusting the cutting each case, their height H _2, G _{For 2} , prepare several kinds of rotating cylinders (1) with different dimensions in advance, and fix the rotating cylinder (1) with the optimum dimensions to the fixed cylinder (2)
Combined with.

[0012]

[Operation and effect] Depending on the height G ₁ from the fixed rotary transformer (9) of the fixed cylinder (2) to the upper surface of the bearing (5), the rotary abutment surface (12) of the rotary cylinder (1) rotates to the rotary rotary. the G ₂ transformer (8) processing the height, and the reference plane from (21) to the bearing upper surface height H ₁ of the stationary cylinder (2)
According to the above, the height from the bearing contact surface (12) of the rotary cylinder (1) to the magnetic head mounting surface (13) up to G ₂ is machined, and the rotary cylinder (4) is used for the machining. By combining (1) and fixed cylinder (2), a rotary transformer
(8) (9) the gap G ₀ between the reference surface of the fixed cylinder (2) (21)
It is possible to set the height H ₀ from the magnetic head to the magnetic head 7 within an allowable range, and it is not necessary to improve the accuracy of the individual parts.

Further, by directly fitting and fixing the rotary shaft (4) on the rotary cylinder (1), the number of parts can be reduced.

Even when a spacer is provided at a required place instead of adjusting and cutting the dimensions H ₂ and G ₂ of the rotary cylinder (1), the same effect as above is obtained except that the number of parts is increased by the spacer. Play.

Further, instead of adjusting and cutting the dimensions H ₂ and G ₂ of the rotary cylinder (1) each time, a plurality of types having different dimensions are prepared in advance, and the rotary cylinder having the optimum dimension is selected. When assembled, the same effects as described above are achieved except for the trouble of preparing rotary cylinders having different dimensions.

[0016]

FIG. 1 shows an embodiment of the head drum of the present invention. Two upper and lower bearings on the axis of the fixed cylinder (2)
The rotary shaft (4) penetrates through (5) and (50),
The rotary cylinder (1) is press-fitted and fixed to the upper end of (4). On the lower surface of the rotary cylinder (1), a bearing abutting surface (12) is formed which is annularly raised along the hole edge of the press-fitting hole (18), and the bearing abutting surface (12) is located above the bearing (5). ) Is pressed against the inner ring (51).

A plurality of grooves (17) are formed in the lower surface of the rotary cylinder (1) in the radial direction, and the magnetic head (7) is mounted on the bottom of the groove to be the magnetic head mounting surface (13) via the mounting plate (72). Tebisu (71)
It is fixed in. Rotating cylinder (1) and fixed cylinder
A rotary rotary transformer (8) and a fixed rotary transformer (9) are adhered and fixed to the facing surfaces of (2), respectively, and a gap G ₀ within an allowable range is formed between both rotary transformers (8) and (9). There is.

The height H ₂ from the bearing butting surface (12) of the rotating cylinder (1) to the magnetic head mounting surface (13) is the reference surface (21) of the lower surface of the fixed cylinder (2) in FIG. From the fixed cylinder reference plane (21) in FIG. 3 to the height H ₀ from the magnetic head (7) to the magnetic head (7) and the inner ring preloaded downward
The magnetic head mounting surface (13) of the rotary cylinder (1) is adjusted and cut so as to have a difference with the height H ₁ to the upper end of (51). That is, the magnetic head mounting surface (13) is processed so that H ₂ = H ₁ −H ₀ .

In FIG. 2, the bearing abutment surface (12) of the rotary cylinder (1) to the rotary rotary transformer mounting surface (14).
Height G ₂ up to fixed rotary transformer in Figure 3
From the height G1 from the upper surface of (9) to the upper end of the inner ring (51), which is preloaded downwardly of the upper bearing (5), the gap G ₀ between the rotary transformers (8) and (9) in FIG. Then, the rotary rotary transformer mounting surface (14) of the rotary cylinder (1) is machined so as to have a value obtained by subtracting the thickness G ₃ of the rotary rotary transformer (8) in FIG. That processed G ₂ = G ₁ -G ₀ rotation -G _three become like rotary transformer attachment surface (14).

By processing the magnetic head mounting surface (13) of the rotary cylinder (1) as described above, the fixed cylinder (2)
The height H ₀ from the reference surface (21) to the magnetic head (7) of the magnetic head mounting surface (13) of the rotary cylinder (1) (within 5 μm) and the magnetic head variation (within 40 μm) It falls within the range of added variation (within 45 μm). or,
Since the rotary cylinder (1) is directly press-fitted and fixed to the rotary shaft (4), the tape sliding contact surface (11) of the rotary cylinder (1) can be concentric with the rotary shaft (4).

As shown by the chain double-dashed line in FIG. 2, an annular recess (19) for applying adhesive is formed on the rotary rotary transformer mounting surface (14) of the rotary cylinder (1), and the rotary transformer abutting surface is formed. When the variation due to the thickness of the adhesive layer of the rotary rotary transformer (8) can be ignored by providing a step between the rotary rotary transformer and the adhesive surface, as described above, the rotary rotary transformer mounting surface (14) of the rotary cylinder By machining the gap G between the rotary transformers (8) and (9)
₀ indicates the variation (5 μm or less) in the machining of the rotary rotary transformer mounting surface (14) of the rotary cylinder (1) and the variation (20 μm) in the thickness G ₃ of the rotary rotary transformer (8).
Within (within 25 μm).

As described above, the head drum of the present invention is shown in FIG.
Flywheel compared to traditional head drums
(3), the spacer (6) for adjusting the gap of the rotary transformers (8) and (9) and the screw (10) for fixing the rotary cylinder (1) to the flywheel (3) are unnecessary.

Further, by directly press-fitting and fixing the rotary rotary transformer (8) to the rotary cylinder (1), as shown in FIG. 2, the winding (14a) of the rotary rotary transformer (8) is directly connected to the magnetic head ( 7), the connection terminals (15) and (16) for the magnetic head (7) and the rotary rotary transformer (8) are not required as in the conventional example shown in FIG.

In the above embodiment, the heights H ₂ and G ₂ from the bearing abutting surface (12) of the rotary cylinder (1) to the magnetic head mounting surface (13) and the rotary rotary transformer mounting surface (14) are set. The case of adjusting and cutting the magnetic head mounting surface (13) and the rotary rotary transformer mounting surface (14) for adjustment was explained.
The heights H ₂ and G ₂ from the bearing abutting surface (12) of the rotating cylinder (1) to the magnetic head mounting surface (13) and from the bearing abutting surface (12) to the rotary rotary transformer mounting surface (14) are measured in advance. Different types of rotary cylinders (1) with different numbers are prepared, or between the rotary rotary transformer mounting surface (14) and the rotary rotary transformer (8), and between the magnetic head mounting surface (13) and the magnetic head (7). Even if a spacer (not shown) is inserted between them, the same effect as described above can be obtained. The present invention is not limited to the configuration of the above embodiment, and various modifications can be made within the scope of the claims.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a head drum of the present invention.

FIG. 2 is a sectional view of a rotary cylinder in which a rotary shaft is press-fitted.

FIG. 3 is a sectional view of a fixed cylinder.

FIG. 4 is a bottom view of the rotary cylinder.

FIG. 5 is a sectional view of a conventional head drum.

[Explanation of symbols]

 (1) Rotating cylinder (12) Bearing abutment surface (13) Magnetic head mounting surface (14) Rotating rotary transformer mounting surface (2) Fixed cylinder (4) Rotating shaft (5) Bearing (7) Magnetic head (8) Rotating Rotary transformer (9) Fixed rotary transformer

Claims (3)

[Claims] 1. A rotary shaft (4) penetrates the shaft center of a fixed cylinder (2) through a bearing (5), and a protruding end of the rotary shaft (4) is a hole of the shaft center of the rotary cylinder (1). (18) is directly fitted and fixed,
The rotary cylinder (1) and the fixed cylinder (2) are respectively provided with a rotary rotary transformer (8) and a fixed rotary transformer (9) facing each other with a clearance within an allowable range.
A method for assembling a head drum having a magnetic head (7) provided in (1), comprising: a height from a reference surface (21) of a fixed cylinder (2) to an end surface of a bearing (5) with which a rotating cylinder (1) abuts. Depending on the height H ₁ and the height G ₁ from the fixed rotary transformer (9) to the end surface of the bearing (5), the magnetic head is mounted from the bearing butting surface (12) of the rotating cylinder (1) to the bearing (5). Face (13)
The height H ₂ and the magnetic head mounting surface to adjust the height G ₂ of the rotation to the rotary transformer attachment surface (14) from the bearing contacting surfaces (12) (13) and the rotating rotary transformer attachment surface up (14) A method for assembling a head drum of a magnetic recording / reproducing apparatus, characterized in that a rotary cylinder (1) and a magnetic head (7) are mounted after adjustment cutting, and then the rotary cylinder (1) and a fixed cylinder (2) are assembled. 2. The rotating shaft (4) penetrates through the shaft center of the fixed cylinder (2) via a bearing (5), and the protruding end of the rotating shaft (4) is a hole of the shaft center of the rotating cylinder (1). (18) is directly fitted and fixed,
The rotary cylinder (1) and the fixed cylinder (2) are respectively provided with a rotary rotary transformer (8) and a fixed rotary transformer (9) facing each other with a clearance within an allowable range.
A method for assembling a head drum having a magnetic head (7) provided in (1), comprising: a height from a reference surface (21) of a fixed cylinder (2) to an end surface of a bearing (5) with which a rotating cylinder (1) abuts. Depending on the height H ₁ and the height G ₁ from the fixed rotary transformer (9) to the end surface of the bearing (5), the magnetic head is mounted on the bearing (5) from the bearing butting surface (12) of the rotary cylinder (1). Face (13)
Between the magnetic head mounting surface (13) and the magnetic head (7) in order to adjust the height H _{2 from the} bearing abutment surface (12) to the height G ₂ from the rotary rotary transformer mounting surface (14). A rotary cylinder (1) with a spacer interposed between the rotary rotary transformer mounting surface (14) and the rotary rotary transformer (8).
A method of assembling a head drum of a magnetic recording / reproducing apparatus, comprising: assembling a fixed cylinder (2) and a fixed cylinder (2). 3. The rotating shaft (4) penetrates through the shaft center of the fixed cylinder (2) through a bearing (5), and the advancing end of the rotating shaft (4) is a hole of the shaft center of the rotating cylinder (1). (18) is directly fitted and fixed,
The rotary cylinder (1) and the fixed cylinder (2) are respectively provided with a rotary rotary transformer (8) and a fixed rotary transformer (9) facing each other with a clearance within an allowable range.
A method for assembling a head drum having a magnetic head (7) provided in (1), comprising: a height from a reference surface (21) of a fixed cylinder (2) to an end surface of a bearing (5) with which a rotating cylinder (1) abuts. Depending on the height H ₁ and the height G ₁ from the fixed rotary transformer (9) to the end surface of the bearing (5), the magnetic head is mounted on the bearing (5) from the bearing butting surface (12) of the rotary cylinder (1). Face (13)
Up to the height H ₂ and the height G ₂ from the bearing abutment surface (12) to the rotary rotary transformer mounting surface (14), prepare a plurality of types of rotary cylinders (1) with different heights in advance and fix them. The rotary cylinder (1) is selected according to the dimension from the fixed rotary transformer (9) of the cylinder (2) to the upper end of the bearing (5) on the rotary cylinder (1) side, and the rotary cylinder (1) and the fixed cylinder ( 2. A method of assembling a head drum of a magnetic recording / reproducing apparatus, which comprises assembling 2).