JPS6058547B2 - Chassis for videotape recorder and method for manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chassis for a video tape recorder (hereinafter referred to as a VTR), particularly a chassis for a VTR (hereinafter simply referred to as a cylinder) having a cylinder base for fixing a cylinder for the VTR (hereinafter simply referred to as a cylinder). Hereinafter, the term "chassis" simply refers to a chassis for a VTR.

In a VTR, the cylinder is not attached directly to the chassis, but rather to a cylinder base fixed to the chassis.

Since strict dimensional accuracy and strength are required to attach the cylinder base to the chassis, the holes through which the cylinder's bearing fixing part passes and the band-shaped holes for the tape guide are formed using an aluminum die on a pressed metal plate. The cylinder base, which is a finished cast product, was fixed with screws, etc. Such a chassis has the drawback that it takes time to finish the cylinder base and to screw the cylinder base to the chassis, and since it is made of metal, there is a limit to how much weight it can be reduced.

The purpose of the present invention is to eliminate these problems and provide an inexpensive and lightweight chassis for a VTR. ■ A VTR chassis having a band-shaped hole for TR located on both sides of the cylinder, and a cylinder base for fixing the cylinder located between the hole through which the bearing fixing part of the cylinder passes and the band-shaped hole, First, the cylinder base is made of resin molded integrally with the chassis.
The second feature is that when manufacturing such a VTR chassis, the cylinder base is molded integrally with the chassis using a mold that has a gate at the position of the hole through which the cylinder bearing fixing part passes. This is a characteristic feature. The present invention was made by experimentally confirming that the required dimensional accuracy and strength can be fully satisfied when the cylinder base and chassis are integrally molded using resin, particularly fiber-reinforced resin. It is.

Examples will be described below.

FIGS. 1a and 1b show an embodiment of the present invention,
FIG. 1a shows a plan view, and FIG. 1b shows a cross section taken along line A--A (7) in FIG.

In these figures, 1 is a hole through which the bearing fixing part (lower end) of cylinder 2 passes, 3 is a cylinder base located around hole 2 for fixing cylinder 2, and cylinder 2 is attached to a video tape. Each length is changed so that it can be fixed at a constant angle α. 4 is located outside the cylinder base 3. The strip-shaped hole 5 for the video tape guide shown in FIG. In such a chassis, the cylinder bay. Cylinder 2 fixed to base 3
Since the videotape runs in contact with the cylinder base 3, strict precision is required regarding the plane intersection angle α of the cylinder base 3, the inclination rate of the boss 5, and the warpage of the flat portion.

Table 1 shows the accuracy required for the chassis and as an example, the chassis was made of unsaturated polyester BMC (bulk molding compound) (CPS-6142WD).
1 Hitachi Chemical Co., Ltd.). The results in this table show that it is possible to integrally mold the cylinder base and chassis with resin with sufficient accuracy. In addition, when we incorporated the molded product with one defect according to this example in place of the conventional product and examined its strength, we found that it did not break, was equivalent to the conventional product, or at least did not interfere with normal use. It was found that it has a high accuracy and strength. Further, according to this embodiment, the work steps such as finishing the cylinder base and the process of attaching the boss and the cylinder base to the chassis can be omitted, thereby significantly shortening the work steps, and producing an inexpensive product.

In addition, in terms of weight, the conventional one weighed about 400g,
It became possible to reduce the weight by half to about 200g. Second
Figures a and b are diagrams illustrating an embodiment of the method for manufacturing a VTR chassis according to the present invention, and show the position of the gate for resin inflow, and the same parts as in Figure 1 are given the same reference numerals. be.

In the figure, a is for the present invention, and b is for comparison. 61 is a gate (hereinafter referred to as the center gate) provided in the hole 1 for the bearing fixing part of the cylinder of the chassis, and 62 is a peripheral part near the end of the strip hole 4 for the videotape guide in the chassis. (hereinafter referred to as the end gate).

This chassis is provided with holes, bosses, etc., so the resin that has flowed into the mold from the gate bypasses the four band-shaped holes, and the flow is disturbed at the boss five. Therefore, the accuracy and strength of the molded product will change depending on the gate position.

Table 2 shows test pieces cut from the weld parts of the center gate molded product and the end gate molded product, and JISK-6911
This shows the results of bending strength (K9/i) determined using a bending test based on .

From this table, it can be seen that in terms of strength, the center gate molded product is superior to the end gate molded product, and the strength of the end gate molded product is about 60% of that of the center gate molded product.
Furthermore, Figures 3a and 3b show the results of comparing the dimensional accuracy of the center gate molded product and the end gate molded product in terms of flatness (warpage at the measurement position with respect to the reference surface). In , the measurement was carried out along the X-X line shown in Fig. 4, and in b, the same was carried out along the Y-Y line. The horizontal axis shows the position (Wn), and the vertical axis shows the deformation (μm). C and E indicate the case of the center gate and the end gate, respectively.

When measured along the X-X line, as shown in Figure a, the deformation of the central gate molded product is -60 to 50 μm;
In either case, the required accuracy is within ±100 pm (curvature ±0.17 n/entire surface shown in Table 1), but the center gate molded product is superior.

Furthermore, when measured along the Y-Y line, as shown in Figure b, the deformation of the central gate molded product is 30 to 74 μm.
However, in the end gate molded product, the deformation was 78 to 113 μm, which exceeded the required accuracy.

These results show that the center gate molded product is superior to the end gate molded product in both strength and dimensional accuracy, and is suitable for VTRs.
This shows that molding with a central gate is better when manufacturing chassis for cars.

In addition, in the above-mentioned example, an example using unsaturated polyester-based BMC was shown, but in Table 3, various fiber-reinforced engineering plastics were used, the cylinder base and chassis were integrally molded, and the intersection angle was measured. Show the results.

As in this example, the intersection angles of fiber-reinforced polysulfone and fiber-reinforced polycarbonate are within the allowable tolerance (±5"). Also, the warp and boss inclination ratio of these two resins are within the allowable tolerance. ■It can be used as a molding material for TR chassis.For thermosetting unsaturated polyester BMC (or SMC (sheet molding compound)), for example, #1102,
#2102 (dia premix), CPS-6
141WB,. CPS-6142WD (Hitachi Chemical), AP9OlS (Toshiba), K-515 (Showa Kobunshi)
, Doufil (Teijin), and CE2O25 (Matsushita Electric Works) were investigated, but all were within the allowable tolerances, and saturated polyester BMC (or SMC) is also generally used as a molding material for TR chassis. can do.

As described above, the TR chassis and its manufacturing method of the present invention allow the cylinder base and chassis to be integrally molded with resin, making it possible to provide an inexpensive and lightweight VTR chassis, resulting in industrial effects. It is a great thing.

[Brief explanation of the drawing]

FIG. 1a is a plan view of the VTR chassis of the present invention, FIG. 1b is a side view, and FIG. Figure 2b
3 is a plan view also shown for comparison, FIGS. 3a and 3b are diagrams similarly showing the effect, and FIG. 4 is a plan view showing the measurement position of FIG. 3. 1... Hole (through which the cylinder bearing fixing part passes), 2... Cylinder (for VTR), 3... Cylinder base, 4... Band-shaped hole (for tape guide), 5...
...Boss, 61...Central gate.

Claims (1)

[Scope of Claims] 1. A hole through which a bearing fixing portion of a videotape recorder cylinder passes, a band-shaped hole for a videotape guide located on both sides of the hole, and a connection between the hole and the band-shaped hole. 1. A video tape recorder chassis comprising a cylinder base located between the chassis and a cylinder base for fixing the cylinder, wherein the cylinder base is made of resin integrally molded with the chassis. 2. The chassis for a videotape recorder according to claim 1, wherein the resin is a fiber-reinforced resin selected from the group consisting of polysulfone, polycarbonate, and unsaturated polyester. 3. A hole through which the bearing fixing portion of the videotape recorder cylinder passes, a band-shaped hole for a videotape guide located on both sides of the hole, and a band-shaped hole located between the hole and the band-shaped hole. A method for manufacturing a chassis for a videotape recorder having a cylinder base for fixing a cylinder, using a mold having a gate at a hole position through which a bearing fixing part of the cylinder passes through the cylinder base; A method for manufacturing a chassis for a video tape recorder, characterized by integral molding.