JP2002134940A - Structure for automatically assembling case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to automatically assemble a case with screws passing through upper holes and lower holes even when the case is formed by using pressed products. SOLUTION: Holes are made in the upper side and the lower side of a case for an electronic control device which is composed of pressed products and the like, and one screw passes through the upper hole and the lower hole. After burring the lower hole, the burring protrusion is enlarged by pressing and the enlarged diameter by pressing is set to 1.3 times of the burred diameter or larger in order that the screw which has passed the upper hole can easily pass the lower hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique relating to automatic assembly of a housing.

[0002]

2. Description of the Related Art In the case of an electronic control unit or the like, a conventionally used case is made of aluminum die-cast, and an upper hole and a lower hole are constituted by through holes. If only the upper hole passes, the lower hole passes without any problem. Therefore, when considering automation, it is sufficient to consider only the upper screw hole.

When a case of an electronic control device or the like is replaced with a stamped product from conventional aluminum die-casting, the portion where the upper hole and the prepared hole are through holes in the conventional case is that the inside of the case is hollow in the pressed product. Therefore, a screw that has passed through the upper hole may not be able to pass through the lower hole and may be stuck.

In order to prevent this catching, the opening diameter of the prepared hole is made larger than the amount of run-out of the screw, and the tip of the screw is made to fall on the opening, and then the opening is made thinner in a funnel shape to reduce the run-out of the screw. It is necessary to converge and pass the prepared hole. As a method for this, generally, a method of processing the prepared hole portion into a funnel shape as described above is used, but in this case, a funnel-shaped portion is formed from the lower surface of the prepared hole portion. Therefore, when the pressed product is further stacked on the lower surface of the prepared hole, the shape design of the pressed product becomes difficult.

If the screw portion is structurally located near a corner, there is a problem that the above-mentioned funnel-shaped portion is over the corner portion, and thus cannot be machined.

As a countermeasure, a method was considered in which after the pilot hole was burred, the burring hole starting side was pushed open by a press so that the screw passing through the upper hole could easily pass through the pilot hole.

[0007] Japanese Patent No. 02763898 discloses an example in which after the burring process, the burring hole starting side is expanded by pressing.
In this case, one metal plate was burred to attach two metal plates, the other plate was pierced, the burring protruding portion was passed through the hole, and then the hole opening side was widened. There is no embodiment in which a plate is fixed and the burring-processed hole opening side is widened as in the present invention to form a funnel so that a screw passing through this hole can pass easily.

[0008]

After burring the pilot hole, the burring opening side is expanded by pressing, and the expanded diameter of the expanded area is set to be at least 1.3 times the burring diameter. Even if the axis is shifted when the screw passes after passing through the upper hole, the screw hits the part expanded in the previous term, converges and can pass through the lower hole, and it is a pressed product made of the current aluminum die cast It is possible to obtain the same assembling property as that of the above.

[0009]

After burring the prepared hole, the burring opening side is pushed out by a press, so that a screw passing through the hole is prevented from being caught by the prepared hole.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.

A burring hole of Φ4.5 is formed by performing burring once, and then the burring hole starting side is expanded by pressing, and the diameter of the expanded portion is set to Φ6.0 which is 1.3 times Φ4.5. It is.

FIGS. 2 and 5 show the structure of a conventionally used housing.

The cover 1, the frame 2, and the base 3 are stacked in this order, and the cover, the frame, and the base are integrally fixed using screws 4 (FIG. 2). Screw 4 and base 3 with thread
, The cover 1 and the frame 2 are sandwiched and fixed (FIG. 5).

The process of passing the screw 4 through the cover 1 and the frame 2 and tightening the screw 4 to the base 3 is automated. As shown in FIG.
To tighten to the base.

The screw 4 can be pushed out by this automatic device,
When the screw 4 is rotated or the like, the tip of the screw 4 oscillates. In this embodiment, an M4 × 30 screw is used, but the tip oscillates up to 3 mm.
2.9, but Φ2.9 + 3 =
A fluctuation of Φ5.9 will occur.

Therefore, in order to allow the screw 4 to pass through the cover 1 and the frame 2 by using this automation device, as shown in FIG. 3, the frontage is widened to facilitate the passage of the screw 4, and the diameter is gradually reduced. The structure is such that the run-out of the screw 4 passing through the frontage is gradually converged.

Since the maximum runout of the screw is in the range of Φ5.9, by setting the diameter of the opening of the cover 1 to Φ6.0 which is 1.3 times the hole Φ4.5, the screw 4 can pass through the frontage. Then, after passing through the cover, Φ4.
5 so as to pass through the burring portion of the base 3.

In this step, as shown in FIG. 3, the frame 3 is made of aluminum die-casting, and has a structure in which the opening portion through which the screw 4 first passes is widened, tapered, and the diameter is gradually reduced. You can do it easily.

Although the frame made of aluminum die-casting is flexible from the viewpoint of automatic assembly as described above, the structure for automation can be flexibly used. Generally, it is more expensive than press products in terms of processing cost.

When this structure is realized by a sheet metal pressed product,
When the structure of the frame is simply replaced with a pressed product, the result is as shown in FIG. 6, where the screw that has passed through the upper hole 2-a of the pressed product is caught by the lower hole 2-b and cannot be passed through the prepared hole. Higher than aluminum die cast frames.

FIG. 7 shows a structure in which the structure of the present invention is employed in the prepared hole in order to prevent this.

Even if the screw passing through the upper hole 7-a sways as shown in FIG. 4, since the frontage of the lower hole is Φ6, the tip of the screw passes through the frontage, is converged, and passes through the lower hole 7-b. However, it is possible to obtain an automatic assembling property equivalent to that of the current aluminum die-casting frame.

Therefore, by adopting the structure as in the present invention, it is possible to provide a pressed product casing which is less expensive than the current die-casting frame.

FIGS. 7, 8 and 9 show examples of alternative methods for obtaining the same effect as the present invention.

FIG. 7 shows that the upper hole and the lower hole of the pressed product are formed by drilling a normal hole, and another part having the same structure as that of the die casting frame is provided between the upper hole and the lower hole.

Although this is structurally the same as a frame made of aluminum die-casting, there are problems in the man-hours for creating another part and the positional accuracy when assembling this separate part 8-a to a pressed product, and the cost is reduced. It can be said that the structure is expensive in terms of positional accuracy.

FIG. 8 shows an example in which the same inclination as that of the present invention is provided below the surface of the prepared hole 8-b of the pressed product.

In this example, the same effect as that of the present invention can be obtained. However, it is necessary to design the base in consideration of the inclined portion provided. There is a problem in feasibility due to the problem of accuracy.

FIG. 9 is an example for avoiding the problem of the processing accuracy described above.

That is, the inclined portion does not protrude from the surface below the pilot hole 9-b.

With this structure, the same effect as that of the present invention can be obtained. However, since a wide part around the prepared hole 9-b needs to be used to realize this structure, the place where the screw is used is limited to a square. If you want to set up near, you will not be able to use it.

Therefore, as shown in this embodiment, burring is performed once to form a burring hole of Φ4.5, and then the burring hole starting side is expanded by pressing to Φ6.0 which is at least 1.3 times the diameter of the burring hole. By adopting the structure, it has the same automation as the current aluminum frame, there is no need to change the shape of the current base, and there is an effect that a settable screw hole can be made near the corner.

[0034]

According to the present invention, it is possible to automatically assemble screws that penetrate the upper hole and the lower hole even in the case of a housing using a pressed product.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a processing method of the present invention.

FIG. 2 is a diagram illustrating a conventional assembling method.

FIG. 3 is a view showing an aluminum die-cast frame.

FIG. 4 is a view showing a structure of an automatic assembling apparatus.

FIG. 5 is a diagram showing a conventional structure.

FIG. 6 is a diagram showing a corresponding structure in a pressed product.

FIG. 7 is a diagram showing a specific example of the present invention.

FIG. 8 is a diagram showing an alternative.

FIG. 9 is a diagram showing an alternative.

FIG. 10 shows an alternative.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cover, 2 ... Frame, 3 ... Base, 4 ... Screw, 5
... Screw chuck, 6 ... Driver.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shinichi Sato 2477 Takaba, Hitachinaka-shi, Ibaraki F-term in Hitachi Car Engineering Co., Ltd. (Reference) 4E360 AB12 ED02 ED06 ED27 GA06 GA53 GB99 GC02

Claims (1)

[Claims] 1. A structure in which holes are provided on the upper and lower sides of a housing of an electronic control device composed of a pressed product or the like, and the upper hole and the lower hole are penetrated by a single screw, and the prepared hole is burred. Then, the burring hole starting side is pushed and spread by a press, and the spreading diameter by the spreading process is set to 1.3 times or more of the burring processing diameter, so that the screw passing through the upper hole easily passes through the pilot hole. The structure of the housing.