JPS5847559A - Guiding cylinder and production thereof - Google Patents

Abstract

PURPOSE:To produce guiding cylinders having excellent characteristics with good productivity by forming internal molding in one body on the inner side of annular bodies obtained by cutting cylindrical bodies which are produced by plastic working then cutting surfaces for guiding of tapes on the annular bodies. CONSTITUTION:At the same instant of molding a cylindrical body 1 by plastic working, the inside circumferential surface is knurled K. Said body 1 is sliced in accordance with the lengths of upper and lower guiding cylinders 2, 3. Molds are mounted to the resultant upper annular body 1a and the lower annular body 1b in order to mold respective internal moldings, and molten Al is charged under high pressure into the molds, then the molten Al is die cast. After a treatment under heating is applied to the upper and lower cylinders 2, 3 manufactured in such a way, the bodies 1a, 1b are machined over the entire circumferences to be formed with surfaces 2a, 2a and edges 3b for guiding of tapes with low friction. The cylinders 2, 3 are fixed to face to each other by means of a connector 4, and a rotary head pair is located in the opposite space freely turnably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a guide cylinder for a video recorder with excellent productivity and a method for manufacturing the same. Die-casting is one method for molding metal. This method involves injecting molten metal into a mold under high pressure, and the molding time is short and requires special techniques, which results in the formation of cavities and hard spots composed of alkali oxides and impurities.

Therefore, when molding the guide cylinder by cutting the molded body with a cutting tool to form the inner surface of the tape dormer using aluminum die-casting, protrusions are formed due to the tosspots, so tape! Not only was it dangerous to be able to form a smooth and smooth inner surface, but the bite tip was damaged due to hard spots.

Therefore, conventionally, paper guide cylinders have been formed by casting or melt-forging methods, which have low productivity, but even with these methods, cavities and hard spots cannot be completely eliminated.
Unfortunately, the occurrence of defective products cannot be avoided.
- Drawability is a method of forming metal at low cost without forming cavities or hard spots.

However, in this method, unsolidified molten metal is drawn out from a die and molded into a columnar or cylindrical body, and the cross section of the molded product is limited to an irregular shape that matches the shape of the die. Therefore, the guide cylinder cannot be directly drawn out. 'Therefore, in view of the above-mentioned points, the present invention has developed a new and effective method in which the tape guide surface is formed by a ring body formed by drawing, and the ring body is formed by aluminum die-casting, and the guide cylinder and cylinder are integrally formed. This paper aims to propose a guide cylinder and its manufacturing method.

Hereinafter, the present invention will be explained according to an illustrative embodiment. In this embodiment, an upper guide cylinder and a lower guide cylinder are fixed by a connector to form the inner surface of the tape housing, and a pair of rotating heads slightly protruding from the opposing gap between both guide cylinders scans the tape surface to perform recording and reproduction. The present invention is applied to a guide cylinder of this type.

In this practical example, the ring body is integrally formed with the internal molded body without any play, the sand is formed, the knurling is formed in advance on a die that defines the internal shape, and the cylinder is housed by drawing. This cylindrical body (1) forms a knurling (3) on its surface.
As shown in the two-part cutaway cross-section in Figure 1, the thickness 1) is 3'W, and the outer diameter (radius) (R) is set 0.5mm larger than the specified dimensions of the cylinder. . Next, this cylinder (
Cut 1) into rounds according to the lengths of the upper and lower guide cylinders.

Upper ring (1a) and lower ring (lb) II
i. Put up the mold. The upper guide cylinder (2) and the lower guide cylinder (3) K, which are formed by molding an internal molded body in the ring body (la) (lb), are designed to homogenize the Al-based crystals of the ring body and encapsulate impurities. Solution treatment (520℃ 28-10
time) and the precipitation treatment of the silicon and ring components (170°C
Heat treatment is carried out for a predetermined time (=5 to 6 o'clock'rIIU).

This treatment stabilizes the structure of the ring and at the same time reduces the friction coefficient. After heat treatment, the upper guide cylinder (2) is machined with a 0.5 m cutting tool around the entire circumference of the upper ring body (1 turtle), which is free from cavities and spots.
A low-friction tape guide surface (2a) is formed. Similarly, the lower guide cylinder (3) is machined with a cutting tool to form a low-friction tape guide surface (5a) and an oblique tape guide edge (3b).

The upper and lower guide cylinders (
21(3) are fixed facing each other by connectors (4) as in the conventional example, as schematically shown at No. 254, and a pair of rotary heads (not shown) are rotatably arranged in the facing gap. It is possible to produce a guide cylinder assembly with high performance.

As described above, according to this embodiment, in order to form a knurl on the inner surface of the cylinder during the drawing process, the die-cast internal molded body and the ring body are integrated without any distortion in the local direction.
Compared to the conventional integrally molded guide cylinder, there is no inferiority in terms of strength and accuracy. -The undulations on the inner surface of the cylinder are not necessarily limited to -lets, but when forming grooves or protrusions along the axis, they can be formed at the same time as the cylinder is drawn, making the processing extremely easy. becomes easier. Therefore, if necessary, by machining the inner surface of the annular body with a cutting tool in the local direction before or after cutting the cylindrical body, it is possible to further increase the integral strength in the axial direction. Further, in this embodiment, the present invention is applied to a fixed type guide cylinder, but it goes without saying that the present invention can also be applied to a rotary type guide cylinder.

Therefore, according to the great invention, since the tape guide surface is constituted by a ring body manufactured by the drawing method in which no cavities or hard spots are formed, the productivity during processing is high and the effect is great.

[Brief explanation of the drawing]

Each figure shows an embodiment of the present invention, and FIG. 1 shows a cutaway cross-sectional view of the cylinder and an exploded longitudinal cross-sectional view of the second FiPltl guide cylinder assembly. Explanation of main books (1)... Cylinder, (IIL) (lb)... Upper/lower ring body, (2)... Upper guide cylinder, (3)...
- Lower guide cylinder, (2aX5a)...tape guide surface. Figure 1 Manual amendment (voluntary) October 5, 1981 Patent consultant dated September 14, 1981 (lj 2 Name of invention Guide cylinder and its manufacturing method Address of patent applicant making the amendment Keihan, Moriguchi City 2-18 Hondori Name (188) Sanyo Kamiki Co., Ltd. Representative I Ue Ikege Agent Address 2-18-5 Keihan Hondori, Moriguchi Detailed explanation of
column. 6. Contents of amendment + 1J The scope of claims has been amended as shown in the attached sheet. (2) In the first line of page 885 of the specification, "pulling processing method" was corrected to "'plastic processing such as extrusion processing and drawing processing." , Block 31 [Pull out 1
Corrected by "pushing out or pulling out". j41 "Drawing processing" described in the specification, page 3, line 5, page 3, line i, and page 6, line 9, is changed to "plastic processing."
and correction. 151 "Drawing edge processing" described in page 4, line 3 of the specification and page 5, line 20 was corrected to "extrusion processing." The guide cylinder according to claim 1, characterized in that undulations are formed on the circumferential surface of the ring body. ° (3) Manufactured by plastic working. After cutting the cylindrical body and integrally molding the inner molded body in the circular direction of the ring body, the ring body is cut to form a tape. A method for manufacturing a guide cylinder, characterized in that a curved circular surface is formed. A patent claim characterized in that undulations along the vI and tJ1 directions are simultaneously formed on the inner circumferential surface of the cylinder when the integral body is produced. The method for manufacturing the guide cylinder described in item 3 of the scope.

Claims (4)

[Claims] (1) A guide cylinder whose outer circumferential surface is made of an annular body produced by drawing. (2) The guide cylinder according to claim 1, characterized in that the inner surface of the ring is formed with undulations. (3) A guide characterized in that an internal molded body is integrally molded inside a ring body obtained by cutting a cylindrical body produced by drawing, and then the ring body is cut to form a tape inward. How to manufacture cylinders. (4) The method for manufacturing a guide cylinder according to claim 3, wherein 41jF mold is used to temporarily form undulations along the pulling direction of the cylinder during manufacture on the inner surface of the cylinder.