JP2000090634A - Magnetic tape cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic tape cartridge which does not produce wear particles and in which a lid can be opened and closed smoothly for a long period. SOLUTION: In a magnetic tape cartridge, a lid 30 which comprises bearing parts 35 is provided, and a support shaft 84 which supports the lid 30 so as to be freely turned is provided. A draft by which the support shaft 84 can be taken out from a mold easily in a molding operation is formed at the support shaft 84. Then, the hearing parts 35 are supported by the support shaft 84 having the draft angle when they come into face contact with the support shaft 84. In order to bring the bearing parts 35 into face contact with the support shaft 84, for example, a method in which a cylindrical part not having a slant is formed in a part in which the support shaft 84 is placed on the bearing parts 35, a method in which inside wall faces of the bearing parts 35 are formed to be taper faces or the like is available.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape cartridge, and more particularly to a lid for opening and closing an opening of a cartridge case from which a magnetic tape can be pulled out, and a spindle for rotatably supporting the lid. The present invention relates to a magnetic tape cartridge having the same.

[0002]

2. Description of the Related Art FIG. 4 is an exploded perspective view of a magnetic tape cartridge used as a recording medium of a computer or the like. This magnetic tape cartridge 1 is known as a one-reel type. The single reel 3 is formed by ultrasonically welding the upper reel 4 and the lower reel 5, and the magnetic tape 20 is wound around the reel 3. Reel 3
Are housed in a cartridge case formed by fastening an upper cartridge half (hereinafter, referred to as an upper cartridge) 2a and a lower cartridge half 2b (hereinafter, referred to as a lower cartridge) with screws 19.

[0003] The upper reel 4 is provided with a concave boss 4b projecting downward in the figure at the center of a disk-shaped upper flange 4a. A gear portion 4c is formed on the outer periphery of the upper flange 4a. A bearing 6 is press-fitted and fixed in the boss portion 4b, and a spring plug 7 is press-fitted and fixed in a hole at the center of the bearing 6. A reel spring 8 for urging the reel 3 downward in the drawing is interposed between the spring plug 7 and the upper cartridge case 2a.

When the magnetic tape cartridge 1 is not used, the reel 3 is locked by the reel brakes 50 and 51 urged by the brake torsion spring 12 so as not to rotate unexpectedly. When the magnetic tape cartridge 1 is not in use, the magnetic tape cartridge 2 is
0 is completely wound on the reel 3 and the leader tape 21 is attached to the end of the magnetic tape (engaging means for a device such as a computer to introduce the magnetic tape into the tape path).
Is a hook 1 attached to the side of the lower cartridge 2b.
8 is locked to the tip portion.

When the magnetic tape cartridge 1 is used, a lid 30 that can be opened and closed in the cartridge plane direction is attached to the opening 26 of the cartridge case from which the magnetic tape 20 is pulled out.

FIG. 5 shows an assembly structure of the lid 30. The upper cartridge 2a includes a frame 2d and a support shaft 14. The support shaft 14 is mounted with a coil portion 15 c of the lid spring 15 and a pair of bearing portions 35 provided on the lid 30. The lid spring 15 has one leg 15 a supported by the frame 2 d, and the other leg 15 b supported by a recess 37 formed in the support shaft side end 31 of the lid 30, and the lid 30 is moved in the closing direction. (In the direction of arrow A in the figure).

[0007] A lid lock member 40 for locking the opening operation of the lid 30 is assembled to the lid 30. The lid lock member 40 is inserted into the support shaft end 31 of the lid 30 with the boss portion 40a of the lid lock member inserted into the coil portion of the lid lock spring 16. The lid lock spring 16 urges the lid lock member 40 slidable in the thickness direction of the cartridge in the shaft end 31 toward the lower cartridge (not shown) (upward in the drawing). A convex portion 40b is provided at the upper end of the lid lock member 40, and the convex portion 40b engages with a concave portion (not shown) of the lower cartridge, and
Lock release operation of.

As shown in FIG. 5, when the lid 30 is opened in the opening direction (the direction of arrow B in the figure), an opening lever (not shown) provided in a magnetic tape cartridge driving device such as a computer operates. The engagement surface 40c of the lid lock member 40 is pushed down toward the upper cartridge 2a (in the direction of the arrow L in the drawing), and the protrusion 40b at the upper end of the lid lock member 40 is pressed.
Is disengaged from the lower cartridge (not shown). At the same time, the release lever (not shown) applies a pressing force in the cartridge plane direction (the direction of arrow P in the drawing) to the vicinity of the engagement surface 40c of the lid lock member 40, and
To release.

Conventionally, a cartridge case and a lid 30
Is made of a composite material of polycarbonate and glass fiber in order to obtain high accuracy and flame retardancy. On the other hand, the lid lock member 40 has a P
It is made of a low friction material such as OM. The support shaft 14
In order to reduce the cost and obtain high accuracy, it is integrally formed with the upper cartridge 2a. The bearing 35 is also integrally formed with the lid 30 for the same reason.

The support shaft 14 is formed in a tapered shape in which the cross-sectional area decreases toward the projecting tip, and has a so-called draft. Since the support shaft 14 is elongated and the thickness of the upper cartridge 2a provided with the support shaft 14 is thin, if the extraction gradient is small, the support shaft 14 may be broken when removing the molded product from the mold, or the upper cartridge 2 2a may be deformed.

FIG. 6 shows the relationship between the forces acting on the lid 30 and the support shaft 14 when the lid 30 is opened. In the opened state, an opening force F2 by an opening lever (not shown) of the magnetic tape cartridge driving device acts on the support shaft side end 31 of the lid 30. Also, the shaft-side end 3
1, the torque T by the lid spring 15 acts. The spring force in the direction parallel to the opening force F2 due to the torque T is represented by F1.
Then, the load F3 acting on the support shaft 14 becomes F1 and F2
From the difference between

Conventionally, the torque T by the generally used lid spring 15 is about 140 gfcm. The radius R of the support shaft 14 is about 0.2 cm, and the distance D1 from the center of the support shaft 14 to the point of application of the spring force F1 is 0.3 cm.
The distance D2 from the center of the support shaft 14 to the point of application of the opening force F2 is about 1.1 cm. T (torque) = F
If the formula of (force) × D (distance) is applied, F1 = T / D1
= 467gf, F2 = T / D2 = 127fg, and the load F3 acting on the support shaft 14 is F3 = F1-F2 = 34.
0 gf is obtained. The acting direction of the load F3 is opposite to the acting direction of the spring force F1.

[0013]

FIG. 7 is a sectional view taken along line XX in FIG. As shown in FIG. 7, the support shaft 14 has a slope, but the inner wall surfaces of the pair of bearing portions 35 do not have the slope. Therefore, the contact between the peripheral surface of the support shaft 14 and the inner wall surface of the bearing portion 35 is a linear contact, and the contact area is small. Therefore, when the opening and closing operations are repeated, the contact portion tends to be scraped and abrasion powder tends to be generated. In particular, as shown in FIG. 5, when the lid 30 is opened, the opening lever (not shown) rotates the lid 30 while pushing down the lid lock member 40 toward the upper cartridge 2a, so that the pair of bearings 35 Of these, abrasion powder was likely to be generated from the contact portion between the bearing portion on the upper cartridge 2a side and the support shaft 14.

In practice, due to the creep deformation of the support shaft 14 and the bearing portion 35, the contact between the two members becomes a surface contact with a very small area, but the contact area is still small, and the stress generated at the contact portion is 500 kgf / cm. Reaches ^two . Abrasion powder is generated from the contact portion. In particular, a material such as the polycarbonate described above, which provides high accuracy and flame retardancy, has a large friction coefficient (friction coefficient μ = 0.4 to 0.6) as a synthetic resin and generates abrasion powder. It was easy.

The generation of wear powder is not preferable because it causes serious errors such as dropout. Also, when the wear powder enters the contact portion between the support shaft 14 and the bearing portion 35, the smooth opening and closing operation of the lid 30 is hindered,
Because the lid 30 could be closed improperly,
It has been desired to suppress the generation of wear powder.

The material forming the support shaft 14 and the bearing portion 35 is
If the material is changed to a material having good slidability, such as polyacetal, the above-mentioned troubles can be improved. However, in order to prevent the cartridge case and the lid 30 from being deteriorated in flame retardancy and accuracy, the upper cartridge 2a and the support shaft 14, and the lid 30 and the bearing portion 35 are required.
Have a separate structure or are formed by two-color molding, which is not preferable in terms of accuracy and cost.

The present invention has been made based on the above background, and an object of the present invention is to provide a magnetic tape cartridge which can smoothly open and close a lid for a long time without generating abrasion powder.

[0018]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a single magnetic tape reel wound with a magnetic tape and housed in a cartridge case, and a support having a draft provided in the cartridge case. A magnetic tape cartridge having a bearing into which a shaft is inserted, and a lid that rotates around the support shaft and opens and closes an opening of the cartridge case from which the magnetic tape can be pulled out. Are supported by surface contact with the support shaft, and can be achieved by a magnetic tape cartridge.

In order to bring the bearing portion into surface contact with the support shaft having a draft, for example, a method of providing a cylindrical portion having no gradient at a place where the bearing portion of the support shaft is mounted, or a method of providing an inner wall surface of the bearing portion is provided. For example, a method of forming a tapered surface may be used.

In the magnetic tape cartridge having such a configuration, the bearing area is supported on the support shaft by surface contact, so that the contact area is larger than that of the conventional line contact.
Therefore, generation of wear powder due to scraping of the contact portion is suppressed.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. In addition, about the member etc. already demonstrated, description is simplified or abbreviate | omitted by attaching | subjecting the same code | symbol or an equivalent code | symbol in a figure.

FIG. 1 is an exploded perspective view showing an assembly structure of a lid in a magnetic tape cartridge according to a first embodiment of the present invention. As shown in FIG. 1, in the present embodiment, the support shaft 84 is formed in a tapered shape in which the cross-sectional area decreases toward the protruding tip except for a part. In the middle part of the support shaft 84, a cylindrical portion 8 having no gradient is provided.
4a are formed.

The support shaft 84 includes a coil portion 15c of the lid spring 15 and a pair of bearing portions 35 provided on the lid 30.
Is attached. FIG. 2 is a cross-sectional view taken along line XX when the lid spring 15 and the bearing 35 are mounted on the support shaft 84. FIG.
As shown in the figure, the cylindrical portion 8 formed in the intermediate portion of the support shaft 14
The peripheral surface of 4a is in surface contact with the inner wall surface of the bearing 35 on the upper cartridge 2a side.

In the magnetic tape cartridge having such a configuration, a column portion 84a is provided at a position on the support shaft 84 where the bearing portion 35 on the upper cartridge 2a side is mounted, and the circumferential surface of the column portion 84a is The contact with the inner wall surface of the portion 35 is a surface contact. Therefore, the contact area is larger than in the case of conventional line contact or surface contact with a small area due to creep deformation, and generation of wear powder is suppressed. Also,
The support shaft 84 having such a shape can be easily formed.

FIG. 3 shows a second embodiment of the present invention.
It is sectional drawing which shows a spindle and a bearing part. In this embodiment, the support shaft 84 and the bearing 35 of the above-described first embodiment are modified, and the other parts are the same as those of the first embodiment.

In this embodiment, the support shaft 14 is the same as the conventional product shown in FIG. 7, and is formed in a tapered shape in which the cross-sectional area decreases toward the protruding tip. On the other hand, the inner wall surface 95a of the bearing portion 95 is also formed as a tapered surface. As shown in FIG. 7, the peripheral surface of the support shaft 14 is in surface contact with the inner wall surface of the bearing 35 on the upper cartridge 2a side.

In the magnetic tape cartridge having such a configuration, since the support shaft 14 is formed in a tapered shape having a smaller sectional area toward the protruding tip as a conventional product, the support shaft 14 is formed from a mold. When taking out the product, there is no fear that the support shaft 14 is broken.

The present invention is not limited to the above-described embodiment, but can be appropriately modified and improved.
For example, in the first embodiment described above, the support shaft 84
Although the cylindrical portion 84a is provided only at the position where the bearing portion 35 on the upper cartridge 2a side is mounted, the cylindrical portion may be provided at the position where the other (lower cartridge side) bearing portion is mounted. . Further, if the plate thickness of the bearing portion 95 in the above-described second embodiment is increased, the contact area between the peripheral surface of the support shaft 14 and the inner wall surface 95a of the bearing portion 95 is increased, and the generation of wear powder is further suppressed. You.

[0029]

According to the magnetic tape cartridge of the present invention, the bearing is supported on the support shaft by surface contact. Therefore, generation of abrasion powder is suppressed as compared with the conventional line contact.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an assembly structure of a lid according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line XX in FIG. 1 when a lid spring and a bearing are mounted on a support shaft.

FIG. 3 is a view showing a support shaft and a bearing according to a second embodiment of the present invention.

FIG. 4 is an exploded perspective view of a conventional magnetic tape cartridge.

FIG. 5 is a perspective view showing a conventional lid assembly structure.

FIG. 6 is a diagram showing a relationship between forces acting on a lid and a support shaft.

FIG. 7 is a sectional view taken along line XX in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic tape cartridge 2a Upper cartridge (upper cartridge half) 2b Lower cartridge (lower cartridge half) 14,84 Support shaft 15 Lid spring 16 Lid lock spring 30 Lid 31 Support shaft side end 35,95 Bearing part 40 Lid lock member 84 Support shaft 84a Column

Claims (1)

[Claims] 1. A single magnetic tape reel wound with a magnetic tape and housed in a cartridge case, and a bearing portion into which a support shaft provided in the cartridge case and having a tapered slope is inserted. A lid which pivots around the support shaft to open and close an opening of the cartridge case from which the magnetic tape can be pulled out, wherein the bearing is supported by the support shaft by surface contact. A magnetic tape cartridge characterized by the above-mentioned.