JPH01276416A - Method for assembling revolving head assembly of magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To eliminate the formation of an air exhausting hole by executing the fitting of a sleeve part in a revolving cylinder to a fixed shaft before a thrust bearing member is mounted to the sleeve part. CONSTITUTION:In order to couple a revolving cylinder 4 to a fixed cylinder 2, at first, a fixed shaft 3 is fixed to the fixed cylinder 3 and necessary parts in a fixing side such as the stator a fixing side rotary transformer 701 and a stator of driving motor 8 are fit. Then, necessary parts in a revolving side such as a magnetic head 6, a revolving side rotary transformer 702 and a rotor of driving motor 8 are fit to the revolving cylinder 4. In such a way, a sleeve part 402 of the revolving cylinder 4 is fit to the outer circumference of the fixed shaft 3. However, at such a time, lubricant 503 is given to the inner surface of the cylinder 4. Finally, lubricant 505 of a thrust fluid bearing 502 is given to an end face 302 of the fixed shaft 3 and a thrust bearing member 405 is pressed by a center pressing jig 10 and fixed by a screw 11. Then, the thrust bearing member 405 is finally fit and an external direction aperture 404 is released up to such a moment. Since the air of a through shaft hole 401 is exhausted from the aperture, the air exhausting hole is eliminated.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a rotary head assembly of a magnetic recording/reproducing device such as a video tape recorder or a digital audio recorder, and particularly to a rotary head assembly of a magnetic recording/reproducing device such as a video tape recorder or a digital audio recorder. This invention relates to a method of assembling a rotatably supported device.

[Conventional technology]

FIG. 2 is an axial cross-sectional view of a rotary head assembly of a conventional video tape recorder. In the figure, (1) shows a magnetic tape, and (2) shows a lead groove (201 ) on the outer peripheral surface (202), (3) is a fixed shaft with one end (301) fixed to the center of the fixed cylinder (2), and (4) is a rotating cylinder; ) includes a sleeve part (402) having a through-shaft hole (401) that is fitted around the outer periphery of the fixed shaft (3), and an outer end part (402) of this sleeve part (402).
A thrust bearing member (405) is mounted on the fixed shaft (3) facing the other end surface (302) of the fixed shaft (3) and closes the outer opening (404) of the through shaft hole (401) of the sleeve portion (402).
). (406) is the thrust bearing member (402)
The main body is fixed to the

(5) is a hydrodynamic bearing device for rotatably supporting the sleeve part (402) from the fixed shaft (3), which supports the sleeve part (402) and therefore also the entire rotating cylinder in the radial direction. It consists of a radial fluid bearing (501) and a thrust fluid bearing (502) that provides axial support.

The radial fluid bearing (501) has lubricating oil (503) (generally oil such as grease) interposed between the outer circumferential surface of the fixed shaft (3) and the inner circumferential surface of the sleeve portion (402), and the outer circumference of these oils. Grooves (5) formed on either the surface or the inner circumferential surface, which generate dynamic pressure by pumping the lubricant (503) when the rotating cylinder (4) rotates, thereby producing a radial bearing action.
04) (It generally consists of a so-called herringbone type Ty shaped like the hiragana "<" character. In the illustrated example, the groove (504) is formed on the outer peripheral surface of the fixed shaft (3), but the sleeve part (402) The thrust fluid bearing (502) may be formed on the inner peripheral surface of the fixed shaft (3).
2) and the inner surface (407) of the thrust bearing member (405) facing the lubricant (505);
The lubricant (505) is formed on either the other end surface (302) of the fixed shaft (3) or the inner surface (407) of the thrust bearing member (405), and is formed on either the other end surface (302) of the fixed shaft (3) or the inner surface (407) of the thrust bearing member (405).
It consists of a groove (not visible in the drawing, but generally herringbone-shaped or crescent-shaped) that generates dynamic pressure by pumping the fluid and produces an axial bearing action. In addition, (6) is supported by the rotating cylinder (4) and the magnetic tape (1)
A magnetic head (7) records information on the magnetic tape (1) and reproduces information already recorded on the magnetic tape (1), and (7) is a signal processing device on the fixed side (Fig. A rotary transformer that transmits and receives the signal without contact between the magnetic head (6) and the fixed rotary transformer (not shown) fixed to the fixed cylinder (2).
701) and a rotating side rotary transformer (702) fixed to the rotating cylinder (4). (8) is a drive motor for rotationally driving the rotary cylinder (4),
(801) is a stator fixed to the fixed cylinder (2);
(802) is a rotor fixed to the rotating cylinder (4).

Next, the operation will be explained. When the drive motor (8) is energized, the rotating cylinder (4) rotates around the fixed shaft (3), and the magnetic head (6) transmits information to the magnetic tape (1) running along the lead groove (201). Record or reproduce information recorded on magnetic tape (1). During this time,
A recording signal or a reproduction signal is transmitted between the magnetic head (6) and the signal processing device via a rotary transformer (7). The radial fluid bearing (501) supports the sleeve portion (402) in the radial direction, and the thrust fluid bearing (502) supports the sleeve portion (402) in the axial direction, thereby substantially supporting the rotating cylinder (4). rotate without resistance.

Next, a conventional method of assembling such a rotary head assembly will be described with reference to FIG. FIG. 3 is an axial sectional view showing the state before the rotating cylinder is combined with the fixed cylinder, and shows the fixed cylinder (2), the fixed shaft (3), the fixed rotary transformer (701), and the drive motor (8). The stator (801) is fixed, the thrust bearing member (405), the main body (406) and the rotating side rotary transformer (702) are fixed to the sleeve part (402), and the main body (406) is fixed.
After fixing the magnetic head (6) to the through hole (40) of the sleeve portion (402) using a dispenser (not shown).
A lubricant (503) is applied to the lower part of the inner peripheral surface of 1) facing the groove (504), and a lubricant (505) is applied to the other end surface (302) of the fixed @ (3). The through shaft hole (401) of the sleeve part (402) of the rotating cylinder (4)
Fit it around the outer periphery of the fixing @(3). At this time, use lubricant (
503) is pushed into the groove (504) by the outer peripheral surface of the fixed shaft (3), and the lubricant (505) is pushed onto the other end surface (302) of the fixed shaft (3) and the inner surface (407) of the thrust bearing member (405). ) and excess lubricant (503)
, (505) are collected in lubricant reservoirs (4os) and (4o9) formed in the sleeve portion (402).

When assembling this, it is necessary to exhaust the air in the through hole (401) of the sleeve part (402) to the outside.
For this purpose, the sleeve part (402) has an air vent hole (41
0) is formed.

[Problem to be solved by the invention]

In the rotary head assembly of the conventional magnetic recording/reproducing device, the thrust bearing member (405) is connected to the sleeve part (405) as described above.
After attaching the sleeve part (402) to the fixed shaft (3), the sleeve part (402) is assembled by fitting it onto the fixed shaft (3).
2) requires an air vent hole (410), which makes manufacturing the sleeve portion (402) troublesome, and also allows dust to enter the hydrodynamic bearing device (5) through the air vent hole (410), causing damage to the hydrodynamic bearing device (5). 5) There were problems such as the bearing performance being impaired.

This invention was made to solve the problems of the conventional products, and it is not necessary to form an air vent hole in the sleeve part, so the sleeve part can be manufactured easily, and dust can pass through the air vent hole. An object of the present invention is to provide a method for assembling a rotary head assembly for a magnetic recording/reproducing device without the intrusion of foreign matter.

[Means to solve the problem]

In order to achieve the above object, according to the method of the present invention, the sleeve portion of the rotary cylinder is fitted onto the fixed shaft before the thrust bearing member is attached to the sleeve portion.

[For production]

In the present invention, when the sleeve portion of the rotating cylinder is fitted onto the fixed shaft, the thrust bearing member is not yet attached to the sleeve portion, and the through shaft hole of the sleeve portion communicates with the outside air through its outer opening. Therefore, the air in the through shaft hole is discharged to the outside through the outer opening.

〔Example〕

Hereinafter, a method of assembling a rotary head assembly according to an embodiment of the present invention will be explained with reference to FIG. FIG. 1 is an axial sectional view showing a state before the rotary cylinder is assembled with the stationary cylinder, and the same parts as those in FIGS. 2 and 3 are given the same reference numerals, and the explanation thereof will be omitted.

To combine the rotary cylinder (4) with the fixed cylinder (2), in addition to fixing the fixed shaft (3) to the fixed cylinder (2) prior to this combination, the fixed side rotary transformer (7
01) and the stator (801) of the drive motor (8) and other fixed-side necessary parts are attached to the fixed cylinder (2). On the other hand, necessary components on the rotation side such as a magnetic head (6), a rotation side rotary transformer (702), and a rotor of a drive motor (8) are attached to the rotation cylinder (4). However, the thrust bearing member (405) is not attached and the sleeve part (405) is not attached.
The outer opening (404) of the through shaft hole (401) in 2) is left open.

In this state, the lubricant (50
3) into the through shaft hole (401) and then the sleeve portion (402) of the rotating cylinder (4) assembled as described above.
is fitted onto the outer periphery of the fixed shaft (3) as shown by the arrow (9). At this time, the lubricant (503) is rubbed upward by the other end surface (302) of the fixed shaft (3) and the groove (504)
) and the portion of the through shaft hole (401) opposite thereto. The excess lubricant (503) then accumulates in lubricant reservoirs (40B) and (409).

Next, the lubricant (505) of the thrust fluid bearing (502) is applied to the other end surface (302) of the fixed shaft (3), and the thrust bearing member (405) is placed in the center holding jig (10).
and fix it to the outer end (403) of the sleeve part (402) with the screw (11). Excess lubricant (SOS) accumulates in a lubricant reservoir (409).

As mentioned above, the sleeve part (40
2) onto the fixed shaft (3), the thrust bearing member (405) has not yet been installed and the sleeve portion (402
Since the outer opening (404) of the through-shaft hole (401) in ) is left open, the air in the through-shaft hole (401) escapes to the outside through the outside opening (404). Accordingly, an air vent hole (410) is provided in the sleeve portion (402) as in the conventional case.
), the manufacture of the sleeve part (402) is simplified, and dust does not enter the hydrodynamic bearing device (5) through the air vent hole (410), thereby improving the hydrodynamic bearing device! The deterioration in bearing performance of f5) is also eliminated.

In the above embodiment, after the sleeve portion (402) is fitted onto the fixed shaft (3), the other end surface (30
Although the lubricant (505) is applied to 2), it may be applied before such fitting. Also, the lubricant (505) is applied not to the other end surface (302) but to the thrust bearing member. (4
05) may be applied to the inner surface (407), or may be applied to both of these. However, the lubricant (503) of the radial fluid ring bearing (501) has grooves (504) on either the outer peripheral surface of the fixed shaft (3) or the inner peripheral surface of the through shaft hole (401) of the sleeve part (402). Regardless of whether it is formed, it should be applied to the sleeve part (402), and it is inconvenient to apply it to the fixed shaft (3). That is, the fixed axis (3)
When applied to the outer circumferential surface of the lubricant (503), the lower end of the sleeve part (402) pushes the lubricant (503) downward to the fixed shaft (3), and the lubricant (503) is pushed downward to the fixed shaft (3) by the groove (504) and the through shaft hole (401) of the sleeve part (402). This is because the amount of intrusion between the two is insufficient.

Further, although the case where the lubricant (503) is applied locally is shown, it may be applied to the entire inner peripheral surface of the through shaft hole (401), and the lubricant (505) may also be applied to the entire inner peripheral surface of the through shaft hole (401). be.

Furthermore, in the above embodiment, when the sleeve part (402) is fitted onto the fixed shaft (3), the sleeve part (402) is already inserted into the fixed shaft (3).
), the main body (406) is fixed to the main body (406).
06) may be fixed to the sleeve portion (402) after such fitting. In addition, the sleeve part (402) and the main body (40
6) may be formed integrally.

〔Effect of the invention〕

As described above, according to the present invention, the sleeve part can be manufactured by fitting the sleeve part onto the fixed shaft fixed to the fixed cylinder before mounting the thrust bearing member of the rotating cylinder on the sleeve part. The present invention is simple, and the effect of preventing dust from entering the hydrodynamic bearing device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining one embodiment of the present invention.
FIG. 2 is an axial cross-sectional view showing the state before the rotary cylinder is assembled with the fixed cylinder; FIG. 2 is an axial cross-sectional view of a rotary head assembly of a conventional video tape recorder; FIG. It is an axial cross-sectional view showing a state before the rotary cylinder is combined with the fixed cylinder, and is a diagram for explanation. In the figure, (1) is the magnetic tape, (2) is the fixed cylinder, (201) is the lead groove, (202) is the outer peripheral surface, (3) is the
) is a fixed shaft, (301) is one end thereof, (302) is the other end surface, (4) is a rotating cylinder, (401) is a through shaft hole, (
402) is the sleeve portion, (403) is its outer end, (
404) is an outer opening, (405) is a thrust bearing member,
(407) is its inner surface, (5) is the hydrodynamic bearing device, (s
o i) is a radial fluid bearing, (502) is a thrust fluid bearing, (503) and (505) are lubricants,
(504) is a groove. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Patent Attorney Masuo Oiwa Figure 2 JLJI i

Claims (1)

[Claims] (1) A fixed cylinder that has a lead groove on its outer circumferential surface that guides the running of the magnetic tape, a fixed shaft that has one end fixed to the center of the fixed cylinder, and a through shaft hole that is fitted into the fixed shaft. A sleeve portion is rotatably supported from the fixed shaft via a hydrodynamic bearing device, and a sleeve portion is attached to the outer end of the sleeve portion so as to face the other end surface of the fixed shaft. The hydrodynamic bearing device has a thrust bearing member that closes the opening on both sides, and a rotary cylinder that supports a magnetic head for recording and reproducing information on the magnetic tape. and a groove formed on either the outer circumferential surface of the fixed shaft or the inner circumferential surface of the sleeve portion, which pumps the lubricant and produces a radial bearing action when the rotary cylinder rotates. a bearing; a lubricant interposed between the other end surface of the fixed shaft and the thrust bearing member; A method for assembling a rotary head assembly for a magnetic recording/reproducing device comprising a thrust fluid bearing comprising a groove for pumping the lubricant to produce an axial bearing action, comprising: fixing the fixed shaft to the fixed cylinder; and fixing the fixed shaft to the fixed cylinder; lubricant is applied to the inner circumferential surface of the part, and the sleeve part thus lubricated is fitted onto the fixed shaft before the thrust bearing member is attached to this sleeve part, and then the thrust bearing member is A rotary head of a magnetic recording/reproducing device, wherein the thrust bearing member is mounted on the outer end of the sleeve portion after lubricating the inner surface of the bearing member or the other end surface of the fixed shaft. How to assemble the assembly.