JP3273655B2 - Manufacturing method of chassis for precision equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a chassis for various precision devices such as a magnetic tape recorder and a magnetic recording / reproducing device such as a floppy disk drive and an optical device such as an optical disk recorder. It is.

[0002]

2. Description of the Related Art A chassis for a precision instrument such as a VTR requires high precision, rigidity and strength in a mounting portion of an important part such as a cylinder head. Speaking of the part to which the cylinder head is attached, for example, the inclination angle is formed at 12.8 °, and the height accuracy is ±
2/100 is required, and even for rigidity and strength,
In order to support the cylinder head which is driven to rotate, a higher one is required as compared with the mounting part of other parts.

[0003] Here, as a chassis for general use, a chassis made of sheet metal having a low manufacturing cost is frequently used.
However, in order to use such a sheet metal chassis for the above purpose, there is a problem not only in accuracy but also in rigidity and strength. That is, in a sheet metal chassis formed by sheet metal pressing or drawing, the dimensional accuracy is ± 15 / due to variations in the thickness of the material, springback during processing, the degree of setting in the mold, and variations in the material hardness. 100-30 / 1
To make up for this, it is necessary to cut or polish the part where important parts are cut or polished in order to compensate for this. If the thickness of the material is from 1.6 mm to 2.0 mm, the thickness of the material is greatly reduced to a value at which the required rigidity and strength cannot be secured when the material is cut. This often occurs, and has not been put to practical use for this reason.

[0004] For this reason, a die-cast product has been conventionally used for the chassis for the above-mentioned application. in this case,
The thickness of each part can be made to correspond to the required rigidity and strength, and the precision required can be ensured by performing precision cutting.

[0005]

However, the necessity of cutting in addition to the die-cast product is extremely costly to manufacture, and in the cutting, dimensional irregularities are caused by wear of the cutting tool. Therefore, it is difficult to stabilize the accuracy and control is difficult, and it is also necessary to clean the chips.

[0006] Although there is a case in which most of the chassis is made of sheet metal and only the vicinity of the mounting portion of the important parts is made of die-casting, it is difficult to use a die-casting product which requires cutting in terms of accuracy. There is no change, and the manufacturing cost has not been sufficiently reduced. The present invention has been made in view of such a point, and an object of the present invention is to provide a chassis for precision equipment which can secure all of accuracy, rigidity and strength and can manufacture a chassis at low cost. To provide a method for manufacturing the same.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to a high-spin plastic working in which a chassis formed of sheet metal is provided with a mounting seat projecting to one side, and a punch performing a conical swing motion is pressed on the surface of the mounting seat. The main feature is that the surface height of the mounting seat is reduced to a predetermined height from the reference plane.

[0008]

According to the present invention, the lack of accuracy due to sheet metal processing is as follows.
High-spin plastic working can correct the required accuracy by high-precision plastic working, and high-spin plastic working does not reduce the material thickness unlike cutting and polishing. It is something you never do.

In performing high-spin plastic working, the rear surface of the chassis near the mounting seat is received by a receiving table which is vertically movable with respect to a lower die for receiving the entire chassis and is fixed in contact with the rear surface. Then, if a punch that performs a conical swing motion is pressed against the surface of the mounting seat, the above-described effect can be obtained even when the rear surface near the mounting seat in the chassis does not coincide with the reference surface.

[0010] The high spin plastic working referred to here is:
Known as a technique used for caulking, usually
As shown in FIG. 5, the round shaft caulking punch 5 is held with the lower end of the rotationally driven main shaft inclined, and the main shaft is rotated to cause the punch 5 to perform a miso-sliding conical swing motion. The tip of the shaft 7 or the stud is plastically deformed to form the stud head 71 by pressing down with a hydraulic pressure or the like while the head is formed by the high spin plastic working. Focusing on the fact that the precision related to processing is high, distortion and deformation are less likely to be applied to parts other than the processed part, and that rigidity and strength can be expected to be improved by work hardening, this processing which was conventionally used only for caulking processing The technology is used for finishing to improve the accuracy of the attachment of important parts in the chassis.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiment. A chassis 1 shown in FIG. 2 is for a VTR and is made of a sheet metal formed by stamping, and a part thereof is formed into an annular shape by drawing. And an inclined surface portion 10 which is inclined at a predetermined angle. A plurality of mounting seats 11 are provided at substantially equal intervals on the outer peripheral portion of the upper surface of the inclined surface portion 10. The reason why the inclined surface portion 10 is formed by drawing and the annular peripheral wall 12 is formed is as follows.
This is for securing the rigidity and strength of the inclined surface portion 10.

The cylinder head 2 is provided with an inclined surface 1
It is fixed on the upper surface of the mounting seat 11 by screws screwed into the cylinder head 2 from below the mounting seat 11 through small holes provided in the mounting seat 11, As described above, the chassis 1 made of sheet metal is used.
The height accuracy of the upper surface of the mounting seat 11 is not sufficient, and if the cylinder head 2 is mounted as it is, the required accuracy cannot be given to the cylinder head 2.

For this purpose, here, as shown in FIG.
The mounting seat 11 is formed as projecting slightly upward from the inclined surface portion 10, and the height H from the reference surface L to the upper surface of the mounting seat 11 is set higher than the regular dimension Hs,
Next, the upper surface of the mounting seat 11 is pressed to a regular dimension by pressing the upper surface of the mounting seat 11 and plastically deforming the upper surface of the mounting seat 11 by high-spin plastic processing in which a punch 5 performing a miso-sliding conical runout motion is pressed on the upper surface of the mounting seat 11. Corrected to Hs. That is, assuming that the height accuracy of the mounting seat 11 when forming the mounting seat 11 by sheet metal processing including sheet thickness variation of the material of the chassis 1 (normally about 5/100 mm) is ± 20/100 mm, Assuming that the design height from the reference plane L of the upper surface of No. 11 is higher than the regular dimension Hs by +20/100 mm, the error is 0
The height is set within the range of +40/100 mm, and then the upper surface of the mounting seat 11 is lowered to the height Hs of the regular dimension by high-spin plastic working.

At this time, in order to press down the mounting seat 11 with the punch 5 which performs a conical swing motion at a high speed and to plastically deform the mounting seat 11, compared with a case where the height is reduced by plastically deforming by hammering or pressing. The pressure may be 1/10 or less, and the spring back after processing is small. Therefore, the height accuracy of the upper surface of the mounting seat 11 can be kept within the above-mentioned range of ± 2/100 mm. Since the height is reduced by doing so, not only does not generate chips as in the case of cutting, but also the thickness and the rigidity and strength do not decrease, the rigidity due to work hardening and An improvement in strength can also be expected.

When such high spin plastic working is performed, although the pressing force is small, the lower surface of the inclined surface portion 10 must be separately received by a member. When the reference surface L does not coincide with the lower surface of the inclined surface portion 10 and there are a plurality of mounting seats 11, the lower surface of the inclined surface portion 10 also has a height error of, for example, ± 20/100 mm. Therefore, if the lower surface around the entire mounting seat 11 is received by a single member, a portion of the lower surface floats from the receiving member due to a variation in height of the lower surface. Even if the height of the upper surface of all the mounting seats 11 is finished to a regular size, the periphery thereof is deformed at the time of processing, and the accuracy is deteriorated by springback.

In order to avoid this, as shown in FIG. 3, the lower die (working jig) 3 which receives the chassis 1 at the time of the high-spin plastic working is independently provided around the respective mounting seats 11 of the inclined surface portion 10. A plurality of receiving bases 30 are provided, and these receiving bases 30 are supposed to be vertically movable with respect to the lower mold 3 and urged upward by individual springs 31. By doing so, when the chassis 1 is set on the lower mold 3 and fixed by the clamp 33, each receiving base 30 surely comes into contact with the lower surface of the peripheral portion of each mounting seat 11. Each of the receiving bases 30 is clamped by a fixing member 32 from the side, for example, so that it does not move up and down. Then, the upper surface of the mounting seat 11 is subjected to high-spin plastic working, and the height of the upper surface is reduced. If the height is lowered to a predetermined height from the reference surface, the lower surface of the peripheral portion of each mounting seat 11 is not affected by the variation in height. The springback is eliminated, so that the upper surface of each mounting seat 11 can be finished with required high precision.

The fixing member 32 and the clamp 33, as well as the lower die 3 and the cradle 30, are not limited to those shown in the figures, and it is preferable to use hydraulic pressure or air pressure in terms of automation. Also, the shape of the mounting seat 11 may be, for example, a shape as shown in FIG. 4. In short, when the height is reduced by plastic deformation by high-spin plastic working,
What is necessary is just to have a convex part having a height that does not become lower than the peripheral part.

[0018]

As described above, in the present invention, the lack of precision in forming by sheet metal working, which is advantageous in terms of manufacturing cost, can be corrected by high-spin plastic working to increase the required precision. Therefore, accuracy does not matter, and high-spin plastic working does not reduce the material thickness unlike cutting and polishing, so that rigidity and strength do not decrease. In addition, since it is easy to obtain a material satisfying both the strength and the strength, the manufacturing cost of the chassis is greatly reduced.

[Brief description of the drawings]

FIGS. 1A and 1B show an embodiment, in which FIG. 1A is a partial sectional view showing a state before high spin plastic working, and FIG. 1B is a partial sectional view showing high spin plastic working.

FIG. 2 is a sectional view showing the overall shape of the above.

FIG. 3 is a cross-sectional view of a state where the same is set on a lower die of the above.

FIG. 4 is a partial sectional view showing another example of the mounting seat.

FIG. 5 shows crimping by high-spin plastic working, in which (a) and (b) are cutaway front views.

[Explanation of symbols]

 1 chassis 5 punch 11 mounting seat

Continuation of the front page (56) References JP-A-3-60829 (JP, A) JP-A-62-212032 (JP, A) JP-A-3-221234 (JP, A) JP-A-4-66242 (JP) JP-A-54-145365 (JP, A) JP-A-4-210838 (JP, A) JP-A-4-75618 (JP, U) JP-A-4-64440 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B21D 31/00 B21D 53/00 H05K 7/04

Claims (4)

(57) [Claims] 1. A mounting seat is provided on a chassis formed of a sheet metal to protrude to one side, and a surface height of the mounting seat is set to a reference plane by high-spin plastic working in which a punch performing a conical swing motion is pressed on the surface of the mounting seat. A method for manufacturing a chassis for precision equipment, characterized in that the height is reduced to a predetermined height. 2. In performing high-spin plastic working, a back surface in the vicinity of a mounting seat of a chassis is received by a cradle that is vertically movable with respect to a lower die that receives the entire chassis and is fixed in contact with the back surface. 2. The method for manufacturing a chassis for precision equipment according to claim 1, wherein a punch performing a conical swing motion is pressed against the surface of the mounting seat in the state. 3. The method for manufacturing a chassis for precision equipment according to claim 1, wherein the surface height of the mounting seat is designed to be higher by an amount corresponding to a height error caused by sheet metal processing. 4. The method for manufacturing a chassis for precision equipment according to claim 2, wherein the receiving base is biased upward by a spring.