JPS6214634B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for manufacturing a tape drive body suitable for, for example, a capstan of a tape recorder.
In particular, it relates to a device that allows the tape to run stably and reliably.

[Technical background of the invention]

As is well known, a tape drive such as a tape recorder capstan is supported as shown in FIG. That is, in the figure, 11 is the main chassis of the tape recorder, and a support cylinder 12 is inserted into a through hole 111 formed at a predetermined position. This support cylinder 12 has a flange 121 formed approximately in the center thereof.
Through holes 122 formed in 1, screws 13 in 122,
13 are inserted through the screw holes 112, 13 formed in the main chassis 11, respectively.
It is fixed to the main chassis 11 by being screwed onto the main chassis 112.

A capstan 14 is inserted into the support cylinder 12. This capstan 14
is adapted to rotate integrally with the flywheel 15 by inserting the lower part thereof in the figure into a through hole 151 formed at the rotational axis of the flywheel 15 and fixing it. Further, the capstan 14 is supported by support members 16 and 17 provided at the upper and lower parts of the support cylinder 12 in the figure so as to rotate smoothly without rattling. The lower end of the capstan 14 in the drawing is in contact with a bearing portion 19 of a sub-chassis 18 that is arranged substantially parallel to the main chassis 11. In addition,
The flywheel 15 is connected to a motor (not shown) via a belt 20 so as to be able to transmit rotational force.

Here, a pinch roller 22 is pressed against the upper part of the capstan 14 in the drawing with a tape 21 interposed therebetween. This pinch roller 22
is rotatable via a support member 25 as shown in the figure, on a shaft 24 implanted in a slider 23 that can move in the directions of arrows A and B in the figure in conjunction with the operation of an operation member for constant speed running of the tape (not shown). It is supported by For example, when the tape is stopped, the flywheel 15 and capstan 14 are rotated stably by the rotational force of the motor described above, but the slider 23 is moved in the direction of arrow B, and the pinch roller 22 is rotated stably. Capstan 14
The tape is not run because it is far away from the station. In this state, when the tape constant speed running operation member is operated, the slider 23
is moved in the direction of arrow A, and the pinch roller 22 is brought into pressure contact with the rotating capstan 14 via the tape 21, as shown enlarged in FIGS. 2a and 2b, and the tape is run here. It is.

Here, the driving force F for the capstan 14 to run the tape 21 is approximately expressed by the following equation.

F=(μ ₁ +μ ₂ )P However, μ ₁ : Coefficient of friction between the tape 21 and the pinch roller 22 μ ₂ : Coefficient of friction between the tape 21 and the capstan 14 P: Pressure force against the tape 21 In other words, the tape runs stably and In order to increase the driving force F for reliable operation, the pressing force P must be increased.
Assuming that is constant, it can be seen that the friction coefficients μ ₁ and μ ₂ can be increased.

On the other hand, since the sliding portion of the capstan 14 with the bearing supported by the support cylinder 12 via the support members 16 and 17 is desired to rotate smoothly, it is desired to reduce the frictional force. In other words, the capstan 14 must be formed so that the portion supported by the support cylinder 12 has low friction, and the tape drive portion to which the pinch roller 22 is pressed has high friction.

For this reason, in the past, the capstan 14 was
It is made of stainless steel, which is a ternary alloy mainly composed of iron (Fe), chrome (Cr), and nickel (Ni), so that the surface is smooth with little friction, and then the pinch roller 22 presses it. For example, the portion that will become the tape drive section is subjected to sandblasting or the like. This sandblasting process involves hitting the tape drive part of the capstan 14 with hard particles (such as ceramic) at high speed and scraping off the surface of the tape drive part, thereby forming a rough surface part 26 as shown in FIG. It is to do so. If this is done, as _shown in an enlarged view in FIG. The coefficient of friction _μ2 between the capstan 14 and the capstan 14 can be increased, and as a result, a large driving force can be obtained.

[Problems with background technology]

However, the conventional tape drive manufacturing method as described above has the following disadvantages.
That is, the surface of the capstan 14 subjected to the sandblasting process has minute cracks, distortions, etc., as shown in the photograph (500 times magnification) of FIG.
Therefore, depending on the frequency of use, the tape 21 scratches away the cracks and distorted parts, weakening the driving force, making it impossible to maintain the initial performance for a long period of time, and resulting in poor durability. Also,
In particular, on the sandblasted surface, the above-mentioned components such as iron, chrome, and nickel are randomly exposed. However, since iron is softer than chrome, nickel, etc., it does not interact with the tape 21. The wear due to friction is severe, and this is also a factor that deteriorates durability. Furthermore, since the sandblasting process involves hitting the tape drive portion of the capstan 14 with hard fine particles at high speed and scraping off the surface of the capstan 14, the third
As shown in the figure, the diameter of the sandblasted rough surface portion 26 is smaller than the diameter of the non-sandblasted portion. For this reason, there is also the disadvantage that the rough surface portion 26 is formed eccentrically with respect to the axis of the portion that is not sandblasted.

[Purpose of the invention]

This invention has been made in consideration of the above circumstances, and provides a method for manufacturing an extremely good tape drive body that can run the tape stably and reliably, improves workability, and has excellent durability. The purpose is to

[Summary of the invention]

That is, the method for manufacturing a tape drive body according to the present invention includes a tape drive body formed of an alloy whose main components are iron, chromium, and nickel and having a tape drive portion and a sliding portion with a bearing. a first step of chemically activating the tape drive portion without masking and reacting with acid to mainly dissolve the iron component, thereby forming the surface portion of the tape drive portion into a rough shape; After this first step, a second step of mechanically finishing the sliding portion between the tape drive portion and the bearing to form the tape drive portion to a predetermined dimension leaving a rough surface portion only on the tape drive portion. It is characterized by the following:

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. In FIGS. 6 and 7, the same parts as in FIGS. 3 and 4 are designated by the same symbols and explained. That is, capstan 14
is made of an alloy of soft metal materials such as iron (Fe) and hard metal materials such as chromium (Cr) and nickel (Ni). The tape drive portion of the capstan 14 that is pressed against the pinch roller 22 is finished mechanically polished, for example, and then subjected to surface treatment to be described later to form a rough surface portion 27 free from minute cracks and distortions. At the same time, the axis of the rough surface portion 27 is made to coincide with the rotation axis of the capstan 14.

In this way, as shown in an enlarged view in FIG. 7, when the pinch roller 22 is in pressure contact with the capstan 14 via the tape 21, the friction coefficient μ ₁ between the tape 21 and the pinch roller 22 and the tape 2
1 and the capstan 14, and as a result, _a large tape driving force can be obtained, and there are no minute cracks or distortions, so the initial driving force can be maintained even after long-term use. Durability can be improved without loss.

Further, here, the soft metal material such as iron is located in the concave portion of the rough surface portion 27, and the hard metal material such as chrome or nickel is located in the protruding portion. In addition, all parts of the capstan 14 that come into direct contact with the tape 21 can be made of a hard metal material, which is particularly effective in terms of durability.

Therefore, means for positioning iron, chrome, and nickel in the concave and protruding portions of the rough surface portion 27 will be explained. That is, this is accomplished by chemically activating the surface of the tape drive portion of the capstan 14 as described above and subjecting it to a surface treatment in which the iron component is mainly dissolved by reacting with acid. Specifically, as shown in FIG. 8, iron (Fe), chromium (Cr), and nickel (Ni) are randomly exposed on the surface of the tape drive portion of the capstan 14. At this time, the component ratio per unit area of iron and, for example, chromium is the 9th
It is as shown in the figure. FIG. 9 is an analysis of the component ratio of iron and chromium per unit area using an X-ray microanalyzer, and it can be seen that iron is considerably larger than chromium.

Then, when the surface of the capstan 14, which is now in the above state, is chemically activated and reacted with acid to dissolve the iron component, the surface of the capstan 14 becomes as shown in FIG. The concave portion of the rough surface portion 27 becomes iron, and the chromium and nickel components remain in the protruding portion.

Here, specific means for the above chemical treatment will be explained. That is, the capstan 14 is chemically treated as follows.

Degreasing: The capstan 14 is cleaned with a degreasing agent, for example, commonly known as Triclean, to remove oil.

Masking (1) As shown in FIG. 11, the portion of the capstan 14 other than the rough surface portion 27 is immersed in a masking liquid (vinyl acetate) 28 and pulled up.

(2) As shown in Figure 12, the capstan 14
is inserted into the through hole 291 of the masking jig 29 from the side with the masking liquid 28 applied, until it reaches the stopper 30, and then pulled out while turning slowly.

(3) Insert the pulled out capstan 14 into the through hole 311 of the drying jig 31 as shown in FIG.

Drying Dry until the capstan 14 does not fall off even if the drying jig 31 is turned upside down.

Chemical porous etching After drying, as shown in FIG. 14, the drying jig 31 is turned upside down and the rough surface 2 of the capstan 14
7 is immersed in a hydrogen fluoride compound solution 32 such as a CPL (chemical polishing liquid) solution for about 2 to 3 minutes at approximately room temperature, thereby mainly dissolving the iron component.

Washing with water Neutralization After washing with water, soak in sodium carbonate solution for about 30 seconds to neutralize. Sodium carbonate (5-10 gr/) Water washing Chromic acid treatment The above chemically porous etched portion is immersed in a sodium dichromate (10 gr/) solution for about 1 minute at room temperature.

Washing with water Removal of masking The capstan 14 is extracted from the drying jig 31 and the masking is removed with ethyl alcohol.

Drying After the chemical treatment described above, the surface of the capstan 14 becomes as shown in the photograph in Figure 15 (500x magnification), and the ratio of iron to chromium is 1.
As shown in the X-ray microanalyzer in Figure 6,
It can be seen that the amount has decreased significantly compared to FIG.

Next, the reason why iron components are mainly dissolved in the chemical porous etching process will be explained. That is, in this case, the hydrogen fluoride compound solution 32 used as the treatment liquid is a mixture of sulfuric acid and hydrofluoric acid as its main components, as represented by CPL liquid, and is expressed by the chemical formula as shown below. It can be done.

H ₂ SO ₄ +2HF→HSO ₃ F+H ₃ O+F ^- …(1) Therefore, when an alloy whose main components are iron (Fe), nickel (Ni), chromium (Cr), etc. is immersed in such a solution, , the following chemical reaction is expected.

(Iron) Fe+2F ^- →FeF ₂ ...(2) (Chromium) Cr+2F ^- →CrF ₂ ...(3) (Nickel) Ni+2F ^- →NiF ₂ ...(4) By the way, in this case, iron according to equation (2) is violent even at room temperature. However, their properties support the fact that chromium and nickel according to equations (3) and (4) hardly react at room temperature, but begin to react when ignited to a high temperature.

In other words, as long as the step is carried out at approximately room temperature (approx. 30°C above room temperature is allowed due to the heat of reaction), only the reaction of equation (2) above will occur, Only the iron content dissolves into the solution through the rough surface of the capstan 14.

Note that strong acid solutions such as hydrochloric acid, sulfuric acid, and nitric acid alone cannot
The ionization tendency sequence of metals based on these is as shown below: K, Na, Ca, Mg, Al, Zn, Cr, Fe〓, Cd, Co, Ni, Sn, Pb, Fe〓, H, Cu, Ag, Hg, Au…(5) Due to the relationship, Fe, Cr, Ni
are close to each other, so the hydrogen fluoride compound solution 32
It was not possible to obtain a characteristic dissolution reaction as in the case of using .

By the way, the manufacturing process for capstans as described above generally consists of cutting the material, quenching, and tempering, and then performing primary processing (polishing, etc.) and secondary processing (polishing) as shown in Figure 17. After it is formed to the specified dimensions through tertiary processing and super finishing, it goes through an inspection process and then goes to surface treatment, so it is masked and chemically coated to prevent the formation of rough surfaces on parts other than the tape drive part. The product is completed by performing a porous etching (CPE) process, then removing the masking and going through the inspection process again.

In this case, applying masking before the chemical porous etching process will prevent the above-mentioned reaction, as shown in Figures 18a and b, even if only the tape drive section is immersed in the processing solution without masking. As a result, hydrogen gas bubbles 32a generated in the solution 32 rise to the surface of the solution and burst. At that time, droplets 32b of the solution adhere to parts that are not immersed in the solution. This is to avoid roughening the part even though it is not as deep as the part immersed in the solution. In other words, since the portion that is not immersed in the solution has been previously formed to a predetermined size as a sliding surface for the bearing, it would be a problem if the surface was roughened up to that portion.

However, applying such masking not only complicates the work process and costs cannot be ignored, but also often causes masking defects, which require a masking removal step after processing. This tends to be further exacerbated by this.

Therefore, the present invention provides a method for manufacturing a tape drive body that can perform surface treatment without masking. It will be realized.

In other words, instead of performing the chemical porous etching process after the tertiary processing and superfinishing to form the capstan to the predetermined final dimensions as in the case of Fig. 17, the secondary processing is performed by reversing the order of these processes. This is followed by a chemical porous etching (CPE) process without masking, followed by tertiary processing and super finishing.

According to this method of manufacturing a tape drive body, the capstan shaft 14' is formed in the form shown in FIGS. 20a, b, and c.
A shows a state in which the capstan is formed by secondary processing to be slightly thicker than the dimensions ultimately required for the capstan. Further, b shows a state in which the portion A attached to the solution by chemical porous etching (CPE) is deeply roughened, and the area B near the top thereof is shallowly roughened. the last C
shows the state in which the entire surface has been subjected to tertiary processing and super finishing to form the final dimensions required for the capstan. In this state, the shallowly roughened portion B in b disappears and only the tape drive section is roughened. A surface portion 27' is formed.

This eliminates the need for masking and masking removal in the surface treatment process, which not only contributes to simplifying the work process and reducing costs, but also makes it possible to prevent problems caused by poor masking and the like.

In the above embodiment, the capstan 14 is shown as the tape drive body, but it goes without saying that it also includes a guide roller such as a tape guide roller.

Furthermore, the present invention is not limited to the above embodiments, and can be implemented with various modifications without departing from the gist thereof.

〔Effect of the invention〕

Therefore, as detailed above, according to the present invention, it is possible to manufacture an extremely good tape drive body that can run the tape stably and reliably, has improved workability, and has excellent durability. method can be provided.

[Brief explanation of the drawing]

Figures 1 and 2 a and b are side sectional views, top views, and side views, respectively, illustrating installation and operation of the capstan, and Figures 3 and 4 are enlarged side views of a conventional capstan, respectively. and a top view, FIG. 5 is a photograph showing an enlarged view of the surface of a conventional capstan, and FIGS. 6 and 7 are side views and FIGS. A top view showing the driving state of the capstan, and Figs. 8 and 9 are side views and characteristics showing the positional relationship and component ratio of iron, chrome, nickel, etc. on the surface of the capstan shown in Fig. 6 after final polishing, respectively. 10 is a side view showing the positional relationship between iron, chromium, nickel, etc. on the surface of the capstan shown in FIG. 6 after chemical treatment, and FIGS. 11 to 14 respectively explain the chemical treatment process. Fig. 15 is a photograph showing the surface of the capstan after the above chemical treatment, Fig. 16 is a characteristic diagram showing the component ratio of iron and chromium after the above chemical treatment, and Fig. 17
The figure is a process diagram schematically showing the entire manufacturing process before the improvement according to the present invention, Figures 18a and b are diagrams for explaining the surface treatment state when masking is not used in Figure 17, and Figure 19 is a process diagram schematically showing the entire manufacturing process improved by this invention, No. 20
Figures a, b, and c are diagrams for explaining the capstan forming process according to FIG. 19. 11... Main chassis, 12... Support cylinder,
13...screw, 14...capstan, 15...
Flywheel, 16, 17... Support member, 18
...Sub chassis, 19...Bearing section, 20...
Belt, 21... Tape, 22... Pinch roller, 23... Slider, 24... Shaft, 25... Support member, 26, 27... Rough surface portion, 28... Masking liquid, 29... Masking jig, 30...Stopper, 31...Drying jig, 32...Hydrofluoride compound solution.

Claims (1)

[Claims] 1. In a method for manufacturing a tape drive body formed of an alloy mainly composed of iron, chrome, and nickel and having a tape drive unit and a sliding part with a bearing, the tape drive unit of the tape drive body is masked. a first step of forming the surface of the tape drive part into a rough shape by chemically activating it without accompanying and reacting with acid to mainly dissolve the iron component;
After this first step, a second step of mechanically finishing the sliding portion between the tape drive portion and the bearing to form the tape drive portion to a predetermined dimension leaving a rough surface portion only on the tape drive portion. A method for manufacturing a tape drive, comprising: