JPH0421983A - Tape cassette - Google Patents

Abstract

PURPOSE:To improve the sliding property against a friction sheet and to obtain the stable tape traveling performance by utilizing impact resistant polystyrene added with a lubricant for a material of a hub. CONSTITUTION:HI-PS(impact resistant polystyrene) added with a lubricant is utilized for the material of the hubs 6 and 7. Silicon is suitably used for the lubricant to be added to this HI-PS. Thus, the hubs 6 and 7 formed by the HI-PS added with silicon as the lubricant have a low friction coefft. against the friction sheet 15, i.e. loss torque is suppressed to a min. because of good sliding property, and moreover because of silicon that is added into the HI-PS, it will never drop out even for long-term use, and hence the hubs 6 and 7 are smoothly rotated, thus obtaining the stable traveling performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tape cassette, and particularly to a hub disposed inside the tape cassette.

[Summary of the invention]

The present invention provides a tape cassette in which a friction sheet is arranged between a hub and a cassette half, and by using HI-PS containing lubricant as the material of the hub, it has good lubricity with respect to the friction sheet, resulting in a stable tape. It is designed to provide good running performance.

[Conventional technology]

First, the structure of a general audio compact cassette will be explained with reference to FIGS. 1 and 2.

In the figure, (1) is a cassette case, and this cassette case (1) is constructed by combining an upper half (2) and a lower half (3) with screws or the like. The upper half (2) and lower half (3) have reel shaft insertion holes (4a) on the left and right sides, respectively.
b) and (5a) (5b) are provided, and a pair of hubs (6) are provided in the cassette case (1) corresponding to the reel shaft insertion holes (4a), (4b), and (5a) (5b). as well as(
7) is rotatably stored. Conventionally this hub (6)
and (7) are made of POM (polyoxymethylene) resin, and a magnetic tape (8) is wound around the circumferential surface of the hub with the end fixedly attached.
) The magnetic tape (8) wrapped around the cassette case (1)
Guide pins (9a) and (9
b) and guide rollers (10a) and (10b)
is guided through the front opening (11) of the cassette case (1).
) is derived. Note that (12) is this front opening (11)
A shield plate (13) arranged on the back side of the magnetic tape (8) is supported in front of this shield plate (12) via a leaf spring (14), and is inserted from the front opening (11). This is a head pad that comes into contact with the magnetic head.

In this tape cassette, hubs (6) (7)
) and the upper half (2), and between the hub (6) (7) and the lower half (3), respectively.
5) is inserted.

Generally, this friction sheet (15) uses a PET (polyethylene terephthalate) film as a base material, and a part of the friction sheet (15) is formed with a protruding strip (15a) that protrudes on the side facing the hub (6) (7). The convex portion (15a) elastically presses and holds the hub (6) (7) and the magnetic tape (8) wound around the hub (6) (7), thereby smoothing the tape. I try to drive safely.

[Problem to be solved by the invention]

However, in the conventional tape cassettes as described above, P is used as the material for the hubs (6) and (7).
OM has a high coefficient of friction between it and the PET friction sheet α, and therefore has a problem in that torque loss during tape running is large and it is difficult to obtain stable running performance.

For this reason, conventional methods have been taken such as applying a lubricant such as silicone to the surface of the friction seat (15), but this silicone gradually falls off due to the sliding rotation of the hubs (6) and (7). Therefore, as the number of trips increases, the running performance deteriorates.

The present invention has been made in view of the above, and an object of the present invention is to provide a tape cassette that can provide stable running performance over a long period of time.

[Means to solve the problem]

In order to achieve the above object, the present invention has a pair of hubs wrapped with magnetic tape rotatably housed in the upper and lower halves of a cassette case, and a friction sheet between the hubs and the cassette halves. In the interposed tape cassette, the hub is formed of Hl-PS to which silicone, for example, is added as a lubricant.

Further, in this case, it is preferable to apply silicone, for example, as a lubricant to the friction sheet.

[For production]

By the means described above, the slipperiness between the hub and the friction sheet becomes good, and as a result, stable running performance can be obtained.

〔Example〕

Examples of the present invention will be described below.

The present invention uses conventional PO as the material for the hubs (6) and (7).
Instead of M, Hl-PS (high-impact polystyrene) to which a lubricant is internally added is used. This HI-P
Silicon is preferably used as the lubricant added to S.

HI-PS with silicon added as a lubricant like this
The hubs (6) and (7) formed by the above have a small coefficient of friction against the friction sheet (15) made of PET, that is, have good lubricity, so loss torque can be suppressed to a low level. Since the hubs are attached, they will not fall off even during long-term use, and as a result, the hubs (6) and (7) rotate smoothly, that is, stable running performance is achieved.

As a result of trial production by the present inventors, the addition rate of silicon to this Hl-PS ranged from 2.5wt% to 3.Qwt%.
% was found to be effective. That is, if the addition rate of silicon is less than 2.5 wt%, the coefficient of friction against the friction sheet becomes large and the above effect is lost, and if the addition rate of silicon is less than 3.5 wt%. If it exceeds Qwt%, the strength will decrease and it will no longer be able to withstand practical use as a hub. Therefore, the silicon addition rate for H>PS is set to 2 iwt% to 3. By selecting Qwt%, a hub with good lubricity against the friction sheet and the required strength can be obtained.

Moreover, after forming the hubs (6) and (7) from H>PS with silicon added therein, the hubs (6) and (7) are further formed on the friction sea (15) side.
It is recommended to apply silicone as a lubricant to the surface facing 7). That is, by coating the friction sheet (15) with silicone, the lubricity between the hubs (6) and (7) and the friction sheet (15) becomes even better, and as a result - stable running properties are obtained, and The silicone coated on the friction sheet (15) has good lubricity between the hubs (6) and (7) and therefore does not fall off easily, ensuring stable running performance of the hub over a long period of time.

FIG. 3 shows a graph comparing running properties of a conventional tape cassette and a tape cassette according to the present invention. In this figure, A and B indicate running properties of a conventional tape cassette, that is, a tape cassette whose hub is formed of POM. A is a case in which no lubricant is applied to the friction sheet, and B is a case in which silicone is applied as a lubricant to the friction sheet. On the other hand, C and D are the runnability of the tape cassette according to the present invention, that is, the tape cassette whose hub is made of HI-PS with a lubricant such as silicone added therein, and C is the running performance when no lubricant is applied to the friction sheet. D is a case where silicone is applied to the friction sheet as a lubricant.

In this running test, a 60-minute cassette (30 minutes on one side) was run from the start end to the end in the playing state, and the time including rewind was counted as one run, and this was repeated 100 times and 200 times.
This is the result of repeated tests. The hub of the tape cassette of the present invention used in this test was Hl-
The addition rate of silicon to PS was selected to be 2.8 wt%.

As is clear from the test results, the friction torque of the conventional tape force sets (A and B) increases as the number of runs increases and the running performance becomes unstable, whereas the tape cassettes of the present invention (C and In D), the friction torque does not increase even if the number of runs increases, and stable running performance is maintained.In particular, when silicone is applied to the friction sheet as a lubricant, (D) shows outstanding running performance and lasts for a long time. It can be seen that stable running is achieved.

In addition to the above-mentioned running performance, HI-PS used as a material for the hub in the present invention is cheaper than conventional POM, so it is advantageous in terms of cost.

Although the embodiments of the present invention have been described above, the present invention is not limited to the compact audio cassette as shown in the drawings, but is of course widely applicable to various tape cassettes incorporating friction sheets.

〔Effect of the invention〕

As explained above, the tape cassette of the present invention has a hub made of HI-PS containing a lubricant, which provides good lubricity to the friction sheet and ensures stable running performance. is the conventional P
Since it is cheaper than OM, it also has the effect of reducing costs, making it possible to provide high-quality tape cassettes at low prices. Also, in this tape cassette,
By applying a lubricant to the friction sheet, the lubricity of the hub is further improved, stable running performance is ensured over a long period of time, and a tape cassette with high layer quality can be realized.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a tape cassette, FIG. 2 is an exploded perspective view of the same, and FIG. 3 is a graph comparing running performance between a conventional tape cassette and the tape cassette of the present invention. In the figure, (1) is the cassette case, (2) is the upper half, and (3) is the cassette case.
) is the lower half, (6) and (7) are the hub, (8) is the magnetic tape, and (15) is the friction sheet. 19th December 1990 Director General of the Patent Office Satoshi Uematsu 1990 Patent Application No. 124783 2 Name of the invention Tape cassette 3 Make an amendment /H Relationship with the case Patent applicant Address: 6-7-35, Kitashina-yo, Tokyo Parts-yo Ward Name (2
1g) Sony Corporation Representative Director Norio Ohga 4, Agent 6, Number of inventions increased by amendment 7, Subject of amendment (1) In the specification, page 6, lines 14 and 16, page 7, line 1 r
2.6wt, + is corrected to '1.3mtJ. (2) Same, page 8, line 17, ``2.8wt'' is rl,
Corrected to 4wJ. that's all

Claims (1)

[Scope of Claims] 1. A tape in which a pair of hubs wrapped with magnetic tape are rotatably housed in the upper and lower halves of a cassette cassette, and a friction sheet is interposed between the hubs and the cassette halves. A tape cassette, characterized in that the hub is made of HI-PS to which a lubricant is added. 2. The tape cassette according to claim 1, wherein a lubricant is applied to the friction sheet.