JPS5848264A - Production of guide cylinder - Google Patents

Abstract

PURPOSE:To form easily a highly precise guide cylinder of a VTR, by fixing a guide cylinder part to a ring body having vertical and horizontal grooves by die casting. CONSTITUTION:Vertical and horizontal grooves V and H are formed to the inner surface of a drawn cylindrical body 1. The body 1 is cut in accordance with the upper and lower cylinder heights to obtain the upper and lower ring bodies 1a and 1b. Then molds are installed in the bodies 1a and 1b, and molten aluminum is poured into these molds. A die casting working is carried out to cut the outer circumferences of the bodies 1a and 1b into the prescribed sizes. In such a way, no shift is caused between the die cast cylinder part and each of the bodies 1a and 1b. Thus the upper and lower guide cylinders 2 and 3 are obtained. These cylinders 2 and 3 are connected to each other via a connector 4. Thus a highly precise guide cylinder for VTR is produced easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a guide cylinder for a video tape recorder with excellent productivity.

One method for molding metal is die casting. This method involves injecting molten metal into the mold at high pressure, and the molding time is short and no special techniques are required.
It is used for various products.

However, in a molded body using this molding method, voids caused by air bubbles, and burst spots composed of an aluminum oxide layer or impurities are formed.

Therefore, when molding a guide cylinder in which a tape guide surface is formed by cutting a molded body using a cutting tool, using the aluminum die-casting method.

Since holes are formed on the tape guide surface due to cavities and protrusions are formed due to hard spots, the Arp plan not only fails to form a smooth inner surface, but also causes damage to the tip of the tool due to bart spouting.・Therefore, guide cylinders have conventionally been molded using casting methods or molten metal forging methods, which have low productivity.

Even with these methods, cavities and hard spots could not be completely eliminated, and the occurrence of defective products could not be avoided.

(Drawing is a method of forming metal at low cost, without forming cavities or hard spots.)

However, in this method, molten metal before solidification is drawn out from a die to be molded into a columnar or cylindrical body, and the cross section of the molded product is limited to a regular shape that matches the shape of the die. Therefore, the guide cylinder cannot be directly drawn out.

Therefore, a method of constructing a guide cylinder by molding an inner molded body into a cylindrical body formed by drawing processing is considered, but this is because the aluminum that is the constituent material of the guide cylinder shrinks as it solidifies.

A gap is formed between the ring body and the molded body, making it impossible to achieve complete integration. It becomes an obstacle for the cylinder.

Therefore, in order to eliminate the above-mentioned backlash, the present invention simultaneously forms grooves or protrusions in the axial direction during drawing processing in order to control backlash in the @ direction, and cuts the cylindrical body to control backlash in the axial direction. Sometimes by forming grooves in the light direction of the inner surface,
The purpose of this invention is to propose a method for manufacturing a guide cylinder that does not cause backlash in either direction of the shaft.

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

In order to
The outer diameter (
I81 is 11 larger than the standard size of the guide cylinder, the thickness 1) is 5l111, and there is one vertical groove IV) on the inner surface.
(See Figure 1).

This cylindrical body (1) is cut according to the heights of the upper guide cylinder and the lower guide cylinder.

A horizontal groove (m) is formed in one direction on the inner surface by machining with a cutting tool, and an upper ring (1a) and a lower ring (1b) are formed.

It should be noted that the order of the horizontal groove formation process and the cutting process i does not matter. The upper ring body (1a) and the lower ring body (1b), which are vertically shaped as described above, are die-cast by installing a mold and injecting molten Alt into the mold in order to mold the inner molded body respectively. Do it. Due to the round molding, the inner molded body forms protrusions corresponding to the horizontal grooves and the vertical grooves (V) of the ring body, so the inner molded body and the ring body are integrated without play. Integrated upper guide cylinder 42
) and the lower guide cylinder (31) are subjected to solution treatment (5
20t: 8 to 10 hours) and heat treatment for a predetermined time to precipitate the silicon component of the ring (175°C: 5 to 6 hours). 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) will have no nests or hard spots.

2. The entire upper ring body (1a) with no holes was cut using a 0.5W cutting tool. Low friction tape guide surface (2a
) to form. Similarly, the lower guide cylinder (81) has a low-friction tape guide surface (
5m) and a diagonal tape guide edge (5b:).

Upper and lower guide cylinders processed in this way +2
1 (31) are fixed facing each other by connectors (4) as in the conventional example as schematically shown in FIG. It is possible to produce a guide cylinder assembly with high performance.

As described above, according to this embodiment, one longitudinal #I(V) is drawn by drawing, and one is
Although the horizontal grooves (H) of the book are formed, the number of #l may be plural, and the longitudinal grooves may be provided with vertical ridges instead of grooves (it is sufficient that undulations are formed).

Therefore, according to the present invention, since the internal molded body is die-cast at low cost in the low-cost ring body, it is possible to provide a guide cylinder with low cost and excellent productivity.

The effect is great.

[BRIEF DESCRIPTION OF THE DRAWINGS] Each figure shows an embodiment of the present invention, and FIG. 1 is a cross-sectional view of the cylindrical body, and FIG. 2 is an exploded longitudinal sectional view of the guide cylinder assembly. Reveal. Explanation of main drawing numbers 11) ---Cylinder, (1, @') (,1,1))-+
+* Upper and lower ring bodies, 12; (31-... Upper and lower guide cylinders, (H)... Horizontal grooves, (V)... Vertical grooves. -!" - Hand - Correction (spontaneous) October 5, 1980 Director General of the Japan Patent Office 1. Indication of the case Patent Commissioner dated September 16, 1932 (3) 1. Name of the invention Guide Cylinder manufacturing method & Patent applicant's address Keihan, Moriguchi City Hondori 2-18 Name (18
8) Sanyo Electric Co., Ltd. Representative Kaoru Iue 4 Agent address: 2-18-5 Keihan Motoyo, Moriguchi City, “Claims” and “Detailed Description of the Invention” of the specification subject to amendment
Next to. 4 Contents of the amendment (1) The scope of the claims has been amended as shown in the attached sheet. (2) "Drawing processing method" stated on page 2, line 14 of the specification has been corrected to "plastic processing such as extrusion processing and drawing processing." (3) “Pull out” written on page 2, line 165 of the specification.
2 corrections by "pushing out and pulling out". (4) "Drawing processing" described in page 2, line 20 of the specification and page 3, line 10 was corrected to "plastic working." (5) "Drawing processing" described in page 4, line 5 of the specification and page 5, line 19 was corrected to "extrusion processing." Claims ``(1) During processing of the cylindrical body, vertical grooves or longitudinal ridges are simultaneously formed on the inner circumferential surface thereof, and while the cylindrical body is cut, horizontal grooves are cut and formed in the circumferential direction of the inner circumferential surface. An annular body made of the above-mentioned annular body is mounted inclined inward in a mold, and a molten material is injected into the mold.An internal molded body is integrally molded inward, and a tape guide surface is cut and formed on the outer periphery of the annular body. Guide cylinder manufacturing method.

Claims (1)

[Scope of Claims] 12) During drawing and punching of the cylindrical body, vertical grooves (or longitudinal protrusions) are simultaneously formed on 11 surfaces of the cylindrical body, and when the cylindrical body is cut, horizontal grooves are formed in one direction on the inside surface. The tape is installed in an annular mold formed by cutting, a molten material is injected into the mold, and an internal molded body is integrally molded inside, and a tape guide surface is formed by cutting on the outer periphery of the annular body. A guide cylinder manufacturing method characterized by: