JPH0487012A - Rotary head assembly for magnetic recording/ reproducing device - Google Patents

Abstract

PURPOSE:To obtain a rotary cylinder having the low cost and the high accuracy by providing a fastening member which is attached to the end part of a center shaft set at the side of the cylinder and also locked to the peripheral part of a center pierced opening of a main body part and holding this peripheral part between the fastening member and the holding face of a support part. CONSTITUTION:A fastening member 16 is attached to the end part of a center shaft 3 set at the side of a rotary cylinder 5 and at the same time locked to a peripheral part 505 of a center pierced opening 504 of a main body part 501. The part 505 is held between the member 16 and the holding face of a support part. Then the part 501 is fixed to a flange part 500 and therefore needs no inserting hole through which a screw is set to fix the part 501 to the part 500. As a result, the structure is simplified and the cost is reduced for the cylinder 5. Furthermore the accuracy of the part 501 and then the cylinder 5 can be improved. Thus it is possible to obtain a rotary head assembly containing a rotary cylinder that assures the prescribed accuracy at the low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary head assembly of a magnetic recording/reproducing apparatus such as a video tape recorder or a digital audio recorder, and particularly to simplifying the structure of the rotary cylinder thereof.

[Prior Art] FIG. 7 is a plan view of a rotary head assembly of a conventional magnetic recording/reproducing apparatus, and FIG. 8 is a longitudinal cross-sectional view taken along the line ■--■ in FIG.

In the figure, (1) shows the magnetic tape, and (2) shows the lead groove (201) that guides the running of the magnetic tape (1) on the outer peripheral surface (
(202) has a fixed cylinder; (3) is a central shaft provided at the center of the fixed cylinder (2) and rotatably supported from the fixed cylinder (2) via a bearing (4); (5);
is a rotating cylinder fixed to a central shaft (3), and consists of a flange part (500) and a main body part (501), and the flange part (500) has a central through hole (502) in its center.
) and a positioning protrusion (503) protruding toward the opposite side of the fixed cylinder (2) are formed, and a center through hole (502) is formed.
) is fixed to the center shaft (3) by press-fitting or shrink-fitting into the center shaft (3), and the main body (501) is formed by the center shaft (3) and the flange (500) fixed thereto. A support part for supporting is configured. In addition, the main body (5
01) has a center through opening (504) corresponding to the positioning projection (503) into which this projection (503) is fitted.
is formed, and the flange portion (500) has a positioning protrusion (
A central through-hole (503) of the main body (501) is provided around the main body (501).
The axial receiving surface (505) for receiving the peripheral part (505) of
06) is formed. However, the protrusion (503
) and the opening (504), the main body (501) is positioned in the radial direction by the protrusion (503) and in the axial direction by the receiving surface (506). It is fixed to the flange part (500) by screws (6) at a plurality of circumferentially spaced positions while being positioned relative to the part (500).

(507) is the outer peripheral surface of the main body (501), and the magnetic tape (1) is connected to this outer peripheral surface (507) and the fixed cylinder (
2) and wraps around the outer peripheral surface (202) over a predetermined angle (for example, 180'). The rotating cylinder (5) is divided into a flange portion (500) and a main body portion (501), which are connected to each other with screws (6). This is because the required predetermined assembly accuracy can be easily obtained by, for example, cutting the receiving surface (506). (7) records information on the magnetic tape (1), or records information on the magnetic tape (
1) A magnetic head for reproducing information already recorded on a rotary cylinder (5) by means of a screw (8).
It is attached to the main body part (501) of. (9) is a rotary transformer for contactlessly transmitting and receiving information between the magnetic head (7) and a fixed side signal processing circuit (not shown), and is a rotary transformer that is fixed to the fixed cylinder (2). A side rotary transformer (901) and a rotating cylinder (
5) and a rotating side rotary transformer (902) fixed to the rotary transformer (902). (10) is a motor that rotationally drives the rotating cylinder (5).

(11) is a relay board provided on the top surface of the rotating cylinder (5), (12) is a signal line whose one end is connected to the magnetic head (7), and the signal line (12) is connected to the magnetic head (7) on the relay board (11). 12
) is printed with a pattern (111) for soldering. The signal line (14) whose negative end is soldered to the pattern (111) is the rotating side rotary transformer (90).
2) is a relay board provided on the top surface, and a pattern (not shown) is printed on this relay board (14), one end of which is connected to the rotating side rotary transformer (902) by a signal line (15). It is connected. And the signal line (
The other end of 13) is soldered to the other end of the relay board (1 AI +-In front 2 pattern), and thus the magnetic head (
7) is connected to the rotating side rotary transformer (902) via the signal line (12), the pattern (111) on the relay board (11), the signal line (13), the pattern on the relay board (14), and the signal line (15). ) is electrically connected to the

Therefore, the main body (501) of the rotating cylinder (5) has a positioning protrusion (503) on the flange (500).
) for fitting and positioning the center through opening (50
4) In addition to the screw insertion hole (508) for the screw (6) and the screw hole (509) for the screw (8), the signal line (12)
A hole (510) for passing the signal line (13) through and a hole (511) for passing the signal line (13) are formed. In addition to these holes, holes (not shown) for a jig used for positioning the magnetic head (7) are also usually provided.

Next, the operation of the rotary head assembly will be explained. When the rotary cylinder (5) is rotated by the motor (10), the magnetic head (7) also rotates around the central axis (3) and is guided along the lead groove (201) to connect the fixed cylinder (2) and the rotating cylinder. The outer peripheral surface of the cylinder (5) (20
2), (507) records and reproduces information on the magnetic tape (1) running above it; At this time, the information to be recorded or reproduced is the rotary transformer (9), the signal line (15), the relay board (
14) Upper pattern, signal line (13), relay board (11)
) is exchanged between the magnetic head (7) and the signal processing circuit via the pattern (111) and the signal line (12).

Generally, there are cutting methods and molding methods for forming the above-mentioned rotating cylinder (5).

When using the cutting method, the material is cut into a predetermined external shape, and the openings and holes (504) and (508) described above are formed.
), (509), (510), (511) and holes for positioning jigs for the magnetic head (7) are also cut. Further, in the case of a molding method, the opening or hole (504) is formed in the mold.

Bottles (508) to (511) for forming holes for jigs are formed, and a suitable molding material such as resin is injected into the mold.

By the way, molded products are generally made by injecting molten molding material into a mold whose temperature is controlled below the solidification temperature of the molding material. The amount of heat released by the molding material into the mold while flowing in the mold is large, the temperature drop is large, and the inside solidifies quickly. Similarly, even at the part far from the gate where molding materials injected from other gates meet, the leading edges of the molding material flows with a significant temperature drop touch, so the two flows do not mix sufficiently and solidify to the inside quickly. , a so-called weld occurs. Therefore, in these parts, the amount of replenishment of molding material to compensate for shrinkage due to cooling is small, and the density becomes low, so that the amount of shrinkage of the molded product increases. On the other hand, in the area near the gate, the temperature drop is small and it is slow to solidify to the inside, so until the gate is closed by cooling and solidification, the area is replenished with molding material to compensate for the shrinkage due to cooling, so the density decreases. As the temperature increases, the amount of shrinkage of the molded product decreases.

It is well known that even when a bottle is formed in the mold, the bottle divides the flow of one molding material into two flows, and that a weld occurs at the part where the two flow on the downstream side of the bottle.

[Problems to be Solved by the Invention] As described above, in the conventional rotating head assembly, it is necessary to form a screw insertion hole in the main body of the rotating cylinder for the screw that fixes the main body to the flange. When forming a rotary cylinder using a cutting method, this hole must be machined with high precision, which poses the problem of increased costs due to an increase in the number of processing steps.Also, when forming a rotating cylinder using a forming method, The need to form a bottle in the mold complicates the structure of the mold, which increases costs, and the welds that occur around the screw insertion holes and the tightening of the screws that fix the main body to the flange require force. There is a problem that accuracy deteriorates due to local distortion of the main body.

This invention was made in order to solve the problems of the conventional ones, and even if formed by any processing method such as cutting or molding, it can achieve the specified precision at a lower cost than the conventional ones. It is an object of the present invention to provide a rotary head assembly for a magnetic recording/reproducing device equipped with a rotary cylinder as obtained.

[Means for Solving the Problems] A rotary head assembly of a magnetic recording and reproducing device according to the present invention is attached to the end of the central shaft on the rotating cylinder side, and is engaged with the peripheral part of the central through-opening of the main body. A fastening member that is stopped is provided, and a peripheral portion of the central through-hole of the main body portion is held between the fastening member and the receiving surface of the support portion.

[Function] In the rotary head assembly of the magnetic recording/reproducing device configured as described above, by sandwiching the peripheral part of the center through opening of the main body between the fastening member and the receiving surface of the support part,
The main body portion is fixed to the flange portion.

[Embodiment 1] An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a plan view showing a rotary cylinder of a rotary head assembly according to an embodiment of the present invention with its main body and fastening member seen through, and FIG. 2 is a sectional view taken along line 11-U in FIG. The same parts as those in the conventional one are given the same reference numerals and the explanation thereof will be omitted.

In the figure, (301) is a male thread formed on the outer periphery of the end (302) of the central shaft (3) on the rotating cylinder (5) side, and (16) is a female thread (16) that is screwed into the male thread (301). 1
61) is formed on the inner periphery, and the bottom surface (162) is formed on the peripheral part (505) of the center through opening (504-) of the rotating cylinder (5).
), the fastening member (17) is a washer.

Connect the female thread (161) of the fastening member (16) to the center shaft (3).
By screwing into the external thread (301) of the fastening member (16), the bottom surface (162) of the fastening member (16) connects to the peripheral part (
505), and thus the peripheral part (505)
is the receiving surface of the fastening member (16) and the flange portion (500) (
506). This results in
The main body (501) will be fixed to the flange (500).

Therefore, in order to fix the main body part (501) to the flange part (500), a screw insertion hole (508) for a screw (6) is provided.
) on the main body (501). Therefore, when forming the rotary cylinder (5) by cutting, cutting of multiple screw insertion holes (508) is no longer necessary, and the number of processing steps is reduced accordingly. This will reduce costs. In addition, when forming by a molding method, there is no need to form a bottle in the mold for forming the screw insertion hole (508), which simplifies the structure of the mold and reduces costs. In addition, when the screw insertion hole (508) is formed, welds that occur around the screw insertion hole (508) are also eliminated, and the accuracy of the main body (501) and, by extension, the rotating cylinder (5) is improved.

Furthermore, the main body (501) caused by the tightening of the screw (6)
) is also eliminated, further improving the accuracy of the rotating cylinder (5). In addition, a plurality of screws (6) are no longer necessary, and the number of parts can be reduced.

In addition, (14A) is a relay board corresponding to (14) of the conventional one, and is attached to the top surface of the rotating side rotary transformer (902), and the pattern (141) is printed on this relay board (14A). has been done. (18) is a signal line connecting the magnetic head (7) to one end of the pattern (141), and the other end of each pattern (141) is connected to the rotating side rotary transformer (902) by the signal line (15). ing. The magnetic head (7) has a flange portion (50
0).

In this way, the magnetic head (7) is connected to the relay board (1) on the rotary transformer (902) by the signal line (18).
Rotating cylinder (5) if connected directly to 4A)
The relay board (11) on the top surface and the signal lines (12) and (13) connected thereto are no longer necessary, so the holes (510) and (51) for passing these signal lines (12) and (13) are no longer necessary.
1) is no longer necessary, and the rotating cylinder (5
), 8-, cutting the holes (510) and (511) becomes unnecessary, which reduces the number of processing steps and further reduces costs. In addition, when forming the holes (510) and (511) using the molding method, there is no need to form bottles in the mold to form the holes (510) and (511), which simplifies the structure of the mold and reduces costs. Not only do
When the holes (510) and (511) are formed, welds that occur around them are also eliminated, and the accuracy of the rotating cylinder (5) is further improved. Moreover, since the relay board (11) and the signal lines (12) and (13) are no longer necessary, the number of parts is reduced and the cost is further reduced.

However, such a configuration is not directly related to the present invention, and the relay boards (11) and (14) may be arranged in the same manner as in the conventional one, as shown in FIG.

The main parts of another embodiment of the invention are shown in longitudinal section in FIG. The difference between this embodiment and the embodiments shown in FIGS. 1 and 2 is that the internal thread (16
1) and the male screw (301) on the outer periphery of the end (302) of the central shaft (3) on the rotating cylinder (5) side is omitted, and the inner periphery (163) of the fastening member (16) is connected to the central shaft (3). ) outer periphery (303) of the end (302) on the rotating cylinder (5) side
The point is that it is fixed by an appropriate means such as press-fitting, shrink-fitting, or adhesion. Even with such a configuration, effects exactly similar to those of the embodiments shown in FIGS. 1 and 2 can be obtained.

The main parts of yet another embodiment of the invention are shown in longitudinal sectional view in FIG. The difference between this embodiment and the embodiment shown in FIG. 3 is that the positioning protrusion (50
Instead of omitting step 3), the diameter of the center through-hole (504) of the main body (501) is made almost the same as the diameter of the center shaft (3), and the center through-hole (5o4) is fitted onto the center shaft (3). The point is that the main body portion (501) is positioned in the radial direction by attaching it by a method such as press fitting. That is, it may be the protrusion (50-3) that fits into the central through-hole (504) for radial positioning, or the central shaft (3) as in this embodiment. In short, it is sufficient that it is located at the center of the support section consisting of the central axis (3) and the flange section (500). In this embodiment, the axial positioning of the main body (501) is performed using the receiving surface (500) formed on the flange (500), as in the case of FIG.
06).

The main parts of yet another embodiment of the invention are shown in longitudinal section in FIG. This embodiment differs from any of the embodiments shown in FIGS. 1 to 4 by forming a step on the portion of the central shaft (3) that protrudes from the flange (500). A receiving surface (304) that receives the peripheral part (505) of the central through opening (504) of the main body (501) is set as a receiving surface (304) that receives the peripheral part (505) of the central through opening (504) of the main body (501). The diameter of the central shaft (3) is approximately equal to that of the small diameter portion, and the center through opening (504) is fitted into this small diameter portion.
The point is that the main body portion (501) is positioned in the axial direction by the receiving surface (304) formed in the axial direction. That is, the axial receiving surface for the peripheral portion (505) may be formed on either the central axis (3) constituting the support portion or the flange portion (500). In addition, the main body part (501)
The radial positioning is performed at the small diameter portion of the central shaft (3).

In addition, in any of the above embodiments, the main body part (501
) is formed with a constant diameter in the thickness direction, but depending on the mounting structure to the support part, the diameter may change in the thickness direction as shown in Fig. 6. It may also be formed as a through opening.

It goes without saying that the present invention is not limited to forming rotary cylinders by cutting or molding methods, but can be applied to objects formed by any other method.

(Effects of the Invention) As described above, according to the present invention, a fastening member is provided which is attached to the end of the central shaft on the rotating cylinder side and is locked to the peripheral part of the central through-opening of the main body. By using an extremely simple structure in which the peripheral part of the central through-hole of the main body is held between the fastening member and the receiving surface of the support part, a rotating cylinder with a predetermined accuracy can be created at a lower cost than conventional ones. This has the effect of providing a rotary head assembly for a magnetic recording and reproducing device equipped with a rotary head assembly.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a rotary cylinder of a rotary head assembly of a magnetic recording/reproducing apparatus according to an embodiment of the present invention, with its main body seen through, and FIG. 2 is a cross section taken along the line - H in FIG. 1. 3 to 5 are longitudinal cross-sectional views of main parts of different embodiments of the present invention, FIG. 6 is a diagram showing a modification of the main body of the rotating cylinder, and FIG. 7 is a conventional magnetic recording/reproducing system. A plan view of the rotary head assembly of the apparatus, FIG. 8, is a sectional view taken along line 1--2 of FIG. In the figure, (1) is a magnetic tape, (2) is a fixed cylinder, (202) is its outer circumferential surface, (3) is a central axis, (30
2) is the end of the central shaft (3), (304) is the receiving surface, (4
) is the bearing, (5) is the rotating cylinder, (500) is its flange, (5o1) is the main body, (502) is the center through hole, (504) is the center through opening, (505) is the main body ( The peripheral part of the central through-opening (504) of (501), (50
6) is a receiving surface, (507) is an outer peripheral surface, (7) is a magnetic head, and (16) is a fastening member. In each figure, the same reference numerals indicate the same or equivalent parts. Agent Patent Attorney Masuo Oiwa

Claims (1)

[Claims] (1) A rotary head assembly for a magnetic recording and reproducing device that records and reproduces information on a magnetic tape, including a fixed cylinder having an outer peripheral surface that guides the running of the magnetic tape, and rotatably supported from the fixed cylinder via a bearing. a rotating cylinder fixed to the central axis and supporting a magnetic head for recording and reproducing information on the magnetic tape, the rotating cylinder having a flange fixed to the central axis and having a central through hole. a main body portion fixed and supported by the support portion, the main body portion having a central through-hole into which the center portion of the support portion consisting of the central axis and the flange portion is fitted, and an outer peripheral surface around which the magnetic tape is wound; In the rotary head assembly for a magnetic recording and reproducing device, the supporting portion is formed with an axial receiving surface for receiving a peripheral portion of the central through-hole of the main body portion, and is attached to an end portion of the central shaft on the rotating cylinder side. , and a fastening member that is locked to a peripheral portion of the central through-opening of the main body is provided, and the peripheral portion of the central through-opening of the main body is sandwiched between the fastening member and the receiving surface. A rotary head assembly for a magnetic recording/reproducing device characterized by: