JP2000195118A - Guide roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate sliding defect of a roller or the like and to maintain high reliability in the running state of a magnetic tape by using a sintered metal for the flange assembled to both ends of the roller which is in sliding contact rotatably with the shaft and by forming a thin film, which is composed of a fluorine-contained polymer, on the surface of the flange which is slid with the roller. SOLUTION: The guide roller is constituted so that a roller 2 is rotatably in contact with a columnar shaft 1 and an upper and a lower flange 3, 4 are assembled to both ends of the roller 2. The flange 3, 4 is composed of a formed body of a sintered metal at least in the face 3a, 4a on the roller 2 side, and a thin film made of a fluorine-containing polymer is formed on the surface of the formed body. The fluorine-containing polymer can be impregnated into fine air holes of the sintered metal, and is desirably a polymer suitable for forming a thin film on the surface, for example, polyfluoro-alkyl polymer or fluoro-polyether polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guide roller.

[0002]

2. Description of the Related Art Generally, a video tape recorder (VT)
R), in a digital audio tape recorder (DAT) or the like, a guide roller is used to guide and transport the tape when recording or reproducing information such as audio and images on a magnetic tape. This guide roller is
It has a roller rotatably supported on a cylindrical shaft, and upper and lower flanges assembled by press-fitting at both ends in sliding contact with the roller. Furthermore, a guide screw for fixing to the support base is attached to the lower side of the lower flange by press fitting. Conventionally, the roller-side sliding contact surface of the flange attached to such a guide roller is:
After turning stainless steel, the surface was polished to a mirror finish, but in recent years, the surface of porous materials such as sintered metal has been polished to improve productivity and reduce manufacturing costs. It has become On the other hand, there is known a guide roller in which a coating made of a fluoropolyether polymer or a polyfluoroalkyl polymer having a functional group having a high affinity for a substrate surface is formed on the surface of a sliding portion or a rolling portion of the guide roller. Yes (Tokuhei 8-31228)
No.).

[0003]

However, if the surface of a porous material such as a sintered metal is polished and used for a flange of a guide roller, the polishing powder remaining in the holes of the flange during running flows out together with water. In addition, poor sliding occurs due to the intrusion between the roller and the sliding surface of the shaft, causing a problem of disturbance of images and sounds. Poor sliding occurs even if the surface-polished sintered metal is sufficiently washed. When sliding failure occurs, the running state of the magnetic tape becomes unstable, and there is a problem that information such as sound and images cannot be recorded or reproduced with high quality.

The present invention has been made to address such a problem. Even if a guide roller is used for polishing a surface of a porous material such as a sintered metal and used for a flange, the sliding of the roller or the like may be performed. It is an object of the present invention to provide a guide roller that can maintain high reliability in a running state of a magnetic tape without causing a defect.

[0005]

A guide roller according to the present invention is a guide roller having a roller rotatably slidably contacted on a shaft and flanges mounted on both ends of the roller. Is made of a sintered metal, and at least a sliding surface with the roller is formed with a thin film made of a fluoropolymer.

Research into the causes of poor sliding of the rollers has been advanced. Fine polishing powder and the like generated during polishing of the sintered metal enter into the pores of the sintered metal, and are sufficiently sufficient in the subsequent cleaning process. It turned out that it could not be removed. As a result, when a sintered metal having a polished surface is used for a guide roller as a flange, the roller is worn by polishing powder or the like remaining on the sliding surface of the roller, and poor sliding occurs.
However, it has been found that when a thin film made of a fluoropolymer is provided on the polished surface of the sintered metal, the polishing powder and the like can be effectively fixed. The present invention has been made based on such knowledge, and it is possible to suppress poor abrasion caused by the attachment of abrasive powder or the like to a roller and further improve the sliding characteristics of the roller.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic tape guide roller mounted on a magnetic recording apparatus according to the present invention will be described with reference to FIG.
FIG. 1 is a sectional view of the guide roller. As for the guide roller, a roller 2 is rotatably slid on a cylindrical shaft 1, and an upper flange 3 and a lower flange 4 are attached to both ends of the roller. A guide screw 5 for fixing to the support base is attached to the lower side of the lower flange 4 by press fitting or the like. A thin film made of a fluoropolymer is formed on at least the surfaces 3a, 4a of the upper flange 3 and the lower flange 4 on the roller 2 side.

The sliding member constituting the flange according to the present invention is made of a sintered metal. Specific examples of the sintered metal include stainless-based sintered metal, bronze, brass, copper-based sintered metal such as nickel silver, aluminum-based sintered metal, titanium-based sintered metal,
A hard metal based sintered metal can be used. Among these, stainless steel sintered metals, such as SUS303, are preferable because there is no risk of running failure due to rust.

In the flange according to the present invention, at least the surfaces 3a and 4a on the roller 2 side are formed of the above-mentioned sintered metal compact, and a thin film of a fluoropolymer is formed on the surface thereof. The surface of the sintered metal compact is polished to improve the slidability. Polishing is preferably performed by barrel polishing or the like, which can increase productivity and reduce manufacturing cost.

The fluoropolymer according to the present invention is capable of impregnating fine pores of a sintered metal and is suitable for forming a thin film on the surface, for example, a polyfluoroalkyl polymer or a fluoropolyether. Polymers are preferred. The polyfluoroalkyl polymer is a polymer having a polyfluoroalkyl group, and an example of the polyfluoroalkyl group is shown in Chemical formula 1.

Embedded image The fluoropolyether polymer has a unit represented by the formula 2 as a main structural unit and preferably has an average molecular weight of 1,000.
~ 50,000 polymers.

Embedded image Here, x is an integer of 1-4.

The fluorine-containing polymer contains a functional group having a high affinity for a metal, for example, an epoxy group, an amino group, a carboxyl group, a hydroxyl group, a mercapto group, an isocyanate group, a sulfone group, an ester group and the like. Desirable, specifically, the following fluoropolymers can be mentioned as examples.

Embedded image

The above-mentioned fluoropolymer may be used alone, but preferably contains an epoxy group or an isocyanate group in consideration of the adhesion to the sintered metal. In the case of an epoxy group-containing fluoropolymer, it is preferable to cure by blending amines, acid anhydrides, curing catalysts and the like. When the isocyanate group-containing fluoropolymer is used alone, it is preferable to add an isocyanate trimerization catalyst such as a tin compound.

[0013] Two or more types of fluoropolymers may be used in combination. In this case, those having an epoxy group and those having at least one group such as an amino group, a carboxyl group, a hydroxyl group, a mercapto group, etc. Or a compound containing a carboxyl group and a compound containing at least one group of an amino group and a hydroxyl group, or a compound containing an isocyanate group and a hydroxyl group, an amino group, a mercapto group, and a carboxyl group. At least one such as a group
It is desirable to take into consideration that a polymer having a high abrasion resistance can be obtained by combining a group containing a type of group or reacting the combined group with each other to make the polymer higher in molecular weight.

Further, an organic compound having a functional group causing a chemical reaction with each of the functional groups may be added to the fluoropolymer having such a functional group to increase the molecular weight. Preferable examples of such a combination include a combination in which ethylene glycol or diaminodiphenylmethane is added to the isocyanate group-containing fluoropolymer, or a combination in which an isocyanate compound or the like is added to the hydroxyl group-containing fluoropolymer.

Although the above-mentioned fluoropolymer itself exhibits a considerable affinity for the material surface of the polished sintered metal flange, depending on the type of sintered metal, it does not necessarily have a sufficient adhesion strength. In such a case, the surface of the sintered metal can be pretreated with a primer having an affinity for the sintered metal material. An example of such a primer is a graft polymer having polymethyl methacrylate as a branch component and a methyl methacrylate unit or a hydroxylethyl methacrylate unit as a trunk component.

The method of applying the fluoropolymer is not particularly limited, and may be a method used for ordinary application.
For example, a thin film can be formed by dissolving or dispersing a fluoropolymer in a suitable solvent and applying (including spraying, dipping, etc.) and then evaporating the solvent. Further, it is also possible to increase the molecular weight of the film forming component by heating after forming the thin film.

The thickness of the fluoropolymer thin film formed on the upper and lower flange surfaces is preferably in the range of 0.2 to 2 μm. Within this range, the dimensional accuracy of the flange surface can be maintained.

The guide roller according to the present invention can be suitably used for a magnetic tape guide roller of a video tape recorder (VTR), a digital audio tape recorder (DAT), a digital video camera (DVC) and the like.

[0019]

EXAMPLES The raw materials used in the examples are shown below collectively. (1) Sintered metal Stainless steel sintered material (SUS303) (2) Fluoropolymer and compounding agent (a) Epoxy group-containing polyfluoroalkyl polymer

Embedded image (B) Amino group-containing polyfluoroalkyl polymer

Embedded image (C) hydroxyl-containing polyfluoroalkyl polymer

Embedded image (D) Isocyanate group-containing fluoropolyether polymer (average molecular weight about 2,000)

Embedded image (E) Hydroxyl group-containing fluoropolyether polymer (average molecular weight about 2,000)

Embedded image (F) Isocyanate compound (average value of n: 0.6)

Embedded image (G) Dibutyltin dilaurate.

Examples 1 to 9 and Comparative Example 1 Using a stainless steel sintered material (SUS303), a diameter of about
A flange having a thickness of about 7 mm and a thickness of about 1.7 mm was prepared, and then barrel-polished. Next, in Examples 1 to 9, the fluorine-containing polymer and the compounding agent shown in Table 1 were diluted with the solvents in the table to 3% by weight to prepare a liquid for forming a thin film. It was applied to the flange and the lower flange. After application 70
The film was heated at 120 ° C. for 1 hour and then at 120 ° C. for 3 hours to form a thin film of about 1 μm thickness. The solvent vertrel XF in the table is a trade name of Mitsui-Dupont Fluorochemical Co., Ltd. In Comparative Example 1, the same flange as in Example 1 was prepared except that a thin film of the fluoropolymer was not formed, and then barrel polishing was performed. In Table 1, the fluorinated polymer and the compounding agent are shown in (a) to (g) above.

The obtained 200 lower flanges were subjected to ultrasonic cleaning with n-hexane, and the cleaning liquid was filtered with Millipore filter paper. The weights of the metal powder and the polishing powder after the filtration were measured, and the polishing powder (mg) was obtained. As shown. In Comparative Example 1, the result of washing with water after barrel polishing was defined as the weight of the polishing powder after filtration. Table 1 shows the measurement results.

[Table 1]

From Table 1, it can be seen that Examples 1 to 9 in which a fluoropolymer was coated showed Comparative Examples 1 to 9 in which metal powder, abrasive powder and the like fell off or flowed out.
It decreased greatly compared with.

Examples 1 to 9 and Comparative Example 1
The guide roller shown in FIG. 1 was assembled using the upper flange and the lower flange obtained in the above. Shaft 1 is SUS42
The roller 2 was made of OJ2 and used an oil-impregnated POM resin composed of polyacetal (POM) resin and silicone oil. The rotational torque and run-out of the obtained guide roller were evaluated by the following test methods. Table 2 shows the evaluation results. (1) Rotation torque test method A measurement plate supported by a hydrostatic air bearing is provided on the concentric rotation disk (diameter 100 mm, thickness 6 mm), and a guide roller for the sample is mounted on this measurement plate. When the rotating body of the guide roller is pressed against the side surface of the rotating disk at a pressure of 20 kgf and the number of rotations is set to 5,000 times per minute, a measurement plate that moves due to friction generated between the rotating body and the support pin is measured by a torque pickup. Using such a guide roller torque measuring device, at 40 ° C and relative humidity at belt tension
The torque (unit: gf · mm) of the guide roller when continuously rotating in an 80% atmosphere was measured continuously for 500 hours, and the change with time was examined. (2) Run-out test method Fix the support pin of the sample guide roller, press the dial gauge (1 / 1,000) against the center of the rotating body, and turn the rotating body gently. The difference between the maximum value and the minimum value of the dial gauge value at this time was determined, and this was defined as the deflection (unit: μm).
With the belt tension, the number of revolutions was set to 5,000 per minute, and the change over time in the run-out value of the guide roller when continuously rotating for 500 hours in an atmosphere of 40 ° C. and a relative humidity of 80% was examined.

[0024]

[Table 2]

According to Table 2, in Examples 1 to 9, the rotational torque fluctuation was stable during the test time of 500 hours. In comparison, in Comparative Example 1, the rotation torque and runout tended to increase from around 200 hours, and generation of wear powder was observed at both ends of the roller. Therefore, by forming the fluoropolymer thin film on the upper flange and the lower flange, the abrasive powder and the like do not fall off, and the running performance of the roller is improved.

[0026]

According to the guide roller of the present invention, since at least the roller sliding surface of the flange is made of a sintered metal on which a thin film made of a fluoropolymer is formed, the sliding characteristics between the upper and lower flanges and the roller are provided. Without interfering with
The performance as a guide roller can be maintained for a long time. In particular, in the case of a flange made of a sintered metal whose surface is polished, it is possible to prevent the generated abrasive powder and the like from falling off even if sufficiently washed. Further, the cleaning process after polishing can be simplified, which can contribute to improvement in productivity.

[Brief description of the drawings]

FIG. 1 is a sectional view of a guide roller.

[Explanation of symbols]

 1 shaft 2 roller 3 upper flange 4 lower flange 5 guide screw

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuo Hirose 970, Ota Anata, Toin-cho, Inabe-gun, Mie Pref. NTN Precision Plastics Co., Ltd. (72) Motoyuki Nishi 2-9-18-403 Higashiyukiya, Ota-ku, Tokyo In the formula company West Precision

Claims (2)

[Claims] 1. A guide roller having a roller rotatably slidably contacted on a shaft and flanges attached to both ends of the roller, wherein the flange is made of sintered metal and slides at least with the roller. A guide roller having a surface on which a thin film made of a fluoropolymer is formed. 2. A guide roller having a roller rotatably slidably contacted on a shaft and flanges mounted on both ends of the roller, wherein the flange is made of sintered metal and slides at least with the roller. A guide roller, characterized in that pores formed in the surface are impregnated with a fluoropolymer.