JPH06291475A - Manufacture of chassis for precision apparatus - Google Patents

Abstract

PURPOSE:To manufacture a chassis at low cost in such a way that its accuracy, its rigidity and its strength can be ensured. CONSTITUTION:A mounting seat 11 which protrudes from one face side is formed in a chassis 1 which has been formed of a sheet metal, and the surface height of the mounting seat 11 is reduced to a prescribed height from a reference face by a high-spin plastic working operation in which a punch 5 performing a conical vibration motion is pressed to the surface of the mounting seat 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a chassis for various precision equipment such as a magnetic recording / reproducing apparatus such as a video tape recorder (hereinafter referred to as VTR) and a floppy disk drive, and optical equipment such as an optical disk recorder. Is.

[0002]

2. Description of the Related Art A chassis for a precision instrument such as a VTR is required to have high precision, rigidity and strength at a mounting portion of an important part such as a cylinder head. As for the portion to which the cylinder head is attached, for example, the inclination angle is 12.8 ° and the height accuracy is ±
2/100 is required, and in terms of rigidity and strength,
In order to support the rotationally driven cylinder head, it is required to be higher than the mounting portion of other components.

Here, as a chassis for general use, a chassis made of sheet metal having a low manufacturing cost is often used.
However, when using such a sheet metal chassis for the above-mentioned purpose, there are problems in terms of rigidity, strength as well as accuracy. That is, in a sheet metal chassis formed by sheet metal pressing, drawing, etc., the dimensional accuracy is ± 15 / due to variations in material thickness, springback during processing, setting in the mold, variation in material hardness, etc. 100-30 / 1
In order to compensate for this, it is necessary to secure the 00 mm, and even if trying to obtain the required accuracy by cutting or polishing the attachment part of the important part, if it is made of sheet metal, cut at the cutting location. Since the thickness cannot be increased, if the thickness of the material is 1.6 mm to 2.0 mm, cutting finish will reduce the thickness and rigidity to the required value. However, it is not practically used because of this.

For this reason, die-cast products have been conventionally used for the chassis for the above applications. 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, since the die-cast product requires a cutting process, the manufacturing cost thereof is extremely high, and the cutting process causes dimensional deviation due to wear of the cutting tool. Therefore, it is difficult to stabilize accuracy and control, and it is necessary to clean chips.

Although most of the chassis are made of sheet metal and die-cast only in the vicinity of the mounting parts of important parts are provided, it is not possible to use die-cast products which require 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 the above points, and an object of the present invention is to provide a chassis for precision equipment, which can secure precision, rigidity, and strength, and can inexpensively manufacture the chassis. In order to provide the manufacturing method of.

[0007]

SUMMARY OF THE INVENTION The present invention, however, provides 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 wobbling motion is pressed against the surface of the mounting seat. The main feature is to reduce the surface height of the mounting seat to a predetermined height from the reference surface.

[0008]

According to the present invention, the lack of accuracy due to sheet metal working is
High-spin plastic processing can correct to the required accuracy, and high-spin plastic processing, unlike cutting and polishing, does not reduce the material thickness, resulting in reduced rigidity and strength. There is nothing to do.

When performing high-spin plastic working, the back surface of the chassis near the mounting seat is received by a pedestal that is vertically movable with respect to a lower die that receives the entire chassis and is fixed in contact with the back surface. By pressing a punch that performs a conical wobbling motion on the surface of the mounting seat, the above-described action can be obtained even if the rear surface of the chassis near the mounting seat does not match the reference surface.

The high-spin plastic working referred to here is
It is known as a technique used for caulking, and usually
As shown in FIG. 5, the round shaft caulking punch 5 is held in a state where the lower end of the rotationally driven main spindle is tilted, and the main spindle is rotated to cause the punch 5 to perform a miso-like conical wobbling motion. Although the shaft 7 and the tip of the tack are plastically deformed to form the tack head 71 by pushing down with hydraulic pressure and the like, the inventors of the present invention have found that the working portion by the high spin plastic working is the working height. It has been used only for caulking in the past, focusing on the fact that it is highly accurate in that it does not cause distortion or deformation to parts other than the processed part and that rigidity and strength can be improved by work hardening. The technology was used for finishing to improve the accuracy of the mounting parts of important parts in the chassis.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the illustrated embodiments. The chassis 1 shown in FIG. 2 is for VTR and is made of punched sheet metal. The peripheral surface 12 is provided and the inclined surface portion 10 that is inclined at a predetermined angle is formed. A plurality of mounting seats 11 are provided on the outer peripheral portion of the upper surface of the inclined surface portion 10 at substantially equal intervals. The inclined surface portion 10 is formed by drawing to form the annular peripheral wall 12,
This is to ensure the rigidity and strength of the inclined surface portion 10.

The cylinder head 2 has an inclined surface portion 1.
It is fixed on the upper surface of the mounting seat 11 in a state of being in contact with the upper surface of the mounting seat 11 by a screw which is arranged on the mounting seat 11 from below the mounting seat 11 and is screwed into the cylinder head 2 through a small hole provided in the mounting seat 11. As mentioned above, the chassis 1 is made of sheet metal.
, 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 reason, here, as shown in FIG.
The mounting seat 11 is formed to project slightly upward from the inclined surface portion 10, and the height H from the reference plane 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 and plastically deformed by high-spin plastic working in which the punch 5 that performs the conical wobble motion of the miso sill is pressed against the upper surface of the mounting seat 11, thereby causing the upper surface of the mounting seat 11 to have a regular dimension height. It is corrected to Hs. That is, assuming that the height accuracy of the mounting seat 11 when forming the mounting seat 11 is ± 20/100 mm when the mounting seat 11 is formed by the sheet metal working including the plate thickness variation of the chassis 1 material (usually about 5/100 mm), the mounting seat Assuming that the design height of the upper surface of 11 from the reference plane L is +20/100 mm higher than the regular dimension Hs, the error is 0
It 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 push down the mounting seat 11 by the punch 5 which performs the conical wobbling motion at high speed for plastic deformation, the punch 5 is pushed down as compared with the case where the height is lowered by plastic deformation by hammering or pressing. The pressure is less than 1/10, 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 range of ± 2 / 100mm mentioned above, and plastic deformation is possible. Since the height is reduced by doing so, not only do chips not occur as in the case of cutting, but also the rigidity and strength do not decrease as the plate thickness decreases, and the rigidity and strength due to work hardening do not decrease. It can also be expected to improve strength.

In the case of performing such high spin plastic working, although the pressing force is small, it is necessary to separately receive the lower surface of the inclined surface portion 10 by a separate member. In addition, when the reference plane 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 all the mounting seats 11 is received by a single member, the height of the lower surface may cause a floating position from the receiving member. Even if the height of the upper surface of all the mounting seats 11 is finished to a regular size, the periphery of the mounting seat 11 is deformed during processing, and the accuracy is deteriorated due to springback.

In order to avoid this, as shown in FIG. 3, the lower die (working jig) 3 for receiving the chassis 1 at the time of high-spin plastic working is independently provided around each mounting seat 11 of the inclined surface portion 10. A plurality of receiving pedestals 30 are provided, and these receiving pedestals 30 are configured to be vertically movable with respect to the lower mold 3 and urged upward by individual springs 31. With this arrangement, when the chassis 1 is set on the lower mold 3 and fixed by the clamps 33, the receiving bases 30 are surely brought into contact with the lower surfaces of the peripheral portions of the mounting seats 11. Each pedestal 30 in FIG. 2 is clamped from the side by a fixing member 32 so as not to move up and down, and then the upper surface of the mounting seat 11 is subjected to high-spin plastic working to adjust the height of this upper surface. By lowering the height from the reference surface to a predetermined height, it is not affected by the variation in the height of the lower surface of the peripheral portion of each mounting seat 11, so that the variation in the peripheral portion of each mounting seat 11 caused by this variation is eliminated. Since the spring back is eliminated, the upper surface of each mounting seat 11 can be finished with the required high accuracy.

Not only the lower die 3 and the pedestal 30 but also the fixing member 32 and the clamp 33 are not limited to those shown in the drawings, and hydraulic pressure or pneumatic pressure is preferably used in terms of automation. Further, the shape of the mounting seat 11 may be, for example, a shape as shown in FIG. 4, and in short, when the height is reduced by plastically deforming by high spin plastic working,
It is sufficient that the convex portion has a height that does not become lower than the peripheral portion.

[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 become a problem, and since high-spin plastic working does not reduce the material thickness unlike cutting and polishing, the rigidity and strength do not decrease. In addition, the manufacturing cost of the chassis can be significantly reduced because it is easy to obtain the one that satisfies both the requirements and the strength.

[Brief description of drawings]

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

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

FIG. 3 is a cross-sectional view of the lower mold set in the same as above.

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

FIG. 5 is a view showing a swaging process by high-spin plastic working, and FIGS.

[Explanation of symbols]

 1 chassis 5 punch 11 mounting seat

Claims (4)

[Claims] 1. A chassis formed of sheet metal is provided with a mounting seat projecting to one surface side, and the surface height of the mounting seat is set to a reference surface by high-spin plastic working in which a punch performing a conical wobbling motion is pressed against the surface of this mounting seat. A method for manufacturing a chassis for precision equipment, which comprises reducing the height to a predetermined height. 2. When performing high-spin plastic working, the back surface of the chassis near the mounting seat is received by a pedestal 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 wobbling motion is pressed against the surface of the mounting seat in this 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 as high as possible in consideration of a height error caused by sheet metal working. 4. The method for manufacturing a chassis for precision equipment according to claim 2, wherein a pedestal urged upward by a spring is used.