JPH09184413A - Oil pan attaching device for internal combustion engine and manufacture of back plate in the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent stress concentration to a joint surface of an oil pan attaching device which is joined to an oil pan and which makes the upper wall of a flange part at the outer periphery of the oil pan, to abut against the lower end wall of a cylinder block through a back plate, by forming the back plate into a ring-like shape, and forming a rounded corner part as viewed in a sectional view. SOLUTION: The upper wall of a flange part 12A at the outer periphery of a recessed oil pan 12 is made to abut against the outer peripheral part of the lower part of a cylinder block 11, and after a back plate 13 is made into contact with the lower wall of the flange part 12A, the oil pan 12 is fastened to the cylinder block 11 by a bolt as a fastening member. In this arrangement, the plate 13 is curved into a ring-like shape along the outer peripheral shape of the oil pan 12 so that the plate 13 is made into contact with the oil pan all over the periphery of the oil pan 12 and accordingly, the surface pressure between the joint surfaces of the cylinder block 11 and the oil pan 12. Further, the plate 13 has rounded comer parts as viewed in a sectional shape, thereby it is possible to prevent stress concentration to each of the corner parts of plate 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil pan mounting device for an internal combustion engine and a method for manufacturing a back plate in the device, and more particularly to a technique for improving the durability of an oipan.

[0002]

2. Description of the Related Art As a conventional example of a device for mounting an oil pan of an internal combustion engine, there are those shown in FIGS. That is, a concave oil pan 2 is disposed below the cylinder block 1, and a flange portion 2A on the outer circumference of the oil pan 2 is attached to the outer peripheral portion of the cylinder block 1 by a bolt 4 via a divided steel back plate 3. It is fixed by tightening. Also,
After the back plate 3 is tightened and fixed with the bolts 4, the back plate 3 and the outer peripheral portion of the oil pan 2 are welded at predetermined intervals as shown in A of FIG. I try to make it uniform.

Here, the back plate 3 is formed by shear cutting a steel flat plate as shown in FIG.

[0004]

However, when the back plate 3 is formed by shear-cutting a flat plate, edge portions B are formed at the corners of the back plate 3 as shown in FIG. When the oil pan 2 is fastened and fixed using the back plate 3, the edge portion B comes into contact with the flange portion 2A of the oil pan 2 (see FIG. 10). Therefore, the surface pressure of the flange portion 2A of the oil pan 2 with which the edge portion B contacts increases,
There is a risk that fretting will occur due to vibrations during engine operation, and this may cause fatigue.

In view of the conventional problems as described above, the present invention prevents stress from concentrating on the joint surface between the oil pan and the back plate and improves the durability of the oil pan. Another object of the present invention is to provide a method for manufacturing a back plate in the device.

[0006]

Therefore, according to the first aspect of the present invention, the upper wall of the flange portion on the outer circumference of the oil pan is brought into contact with the lower wall of the cylinder block, and the lower wall of the flange is provided with a flat back plate. In an oil pan attachment device for an internal combustion engine, which is brought into contact with the cylinder block and fastened to the cylinder block by a fastening member, the back plate is in contact with the entire lower wall of the flange portion. As described above, the back plate is formed in a ring shape, and the corners of the cross section of the back plate are formed in an R shape.

According to a second aspect of the present invention, the lower wall of the cylinder block is brought into contact with the upper wall of the flange portion on the outer circumference of the oil pan, and the lower wall of the flange portion is brought into contact with a flat back plate, and the back plate is attached. In an oil pan mounting apparatus for an internal combustion engine, in which an oil pan is fastened to a cylinder block by a fastening member via a backing plate, a round bar steel material is rolled from both sides along its axis when manufacturing the back plate. A rolling step of forming a plate-shaped member for plate formation, and a bending step of bending the plate-shaped member formed by the rolling step into a ring shape so as to abut over the entire circumference of the flange lower wall. The back plate is manufactured by the process.

The invention according to claim 3 includes a pressing step for flat-pressing the back plate, and, after the bending step,
It was configured to perform a pressing process.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In FIG. 1, the cylinder block 1
The upper peripheral wall of the flange portion 12A on the outer periphery of the concave oil pan 12 is in contact with the outer peripheral portion of the lower part of the first unit 1, and the back plate 13 is in contact with the lower wall of the outer peripheral portion of the oil pan 12. The flange portion 12A of the oil pan 12 is fastened and fixed to the cylinder block 11 together with the back plate 13 by bolts (not shown) as fastening members. As shown in FIG. 2, the back plate 13 is bent and formed in a ring shape in accordance with the outer peripheral shape of the oil pan 12.

When the back plate 13 is formed in a ring shape as described above, the back plate 13 comes into contact with the entire circumference of the oil pan 12, and the surface pressure of the joint surface between the cylinder block 11 and the oil pan 12 is increased. More uniform. Next, a method of manufacturing the back plate 13 will be described. As shown in FIG.
4 is rolled from both sides along the axis by rolling rollers 15A and 15B to form a flat plate 14A having a predetermined thickness (rolling step). At this time, the round bar steel material 14 has such a size that the thickness and width required for the back plate 13 can be obtained.

In this way, the flat plate 14A is replaced with the round bar steel material 1
When formed from 4, the flat plate 14A, as shown in FIG.
The corner portion of the cross section is formed in an R shape. Then, the flat plate 14A is bent into a ring shape by bending in accordance with the outer peripheral shape of the oil pan 12 to form the back plate 13 (bending step).
At the time of this bending, as shown in FIG. 5, since the thick portion C is formed on the inner peripheral edge of the back plate 13, as shown in FIG. To secure the quality (pressing process).

As described above, the flat plate 14A formed by rolling the round bar steel material 14 is bent into a ring shape, and then flat pressed to manufacture the back plate 13. Therefore, the back plate 13 has high flatness, the surface pressure is made uniform over the entire circumference of the joint surface between the cylinder block 11 and the oil pan 12, and the stress concentrates on the corners of the back plate 13. Can be prevented and the durability of the oil pan can be improved.

[0013]

As described above, according to the first aspect of the invention, the back plate for mounting the oil pan on the cylinder block is formed in a ring shape so as to abut over the entire circumference of the flange portion of the oil pan. In addition, since the corners of the cross section are formed in an R shape, the surface pressure is made uniform over the entire circumference of the joint surface between the cylinder block and the oil pan, and stress concentrates at the corners of the back plate. Can be prevented, and the durability of the oil pan can be improved.

According to the second aspect of the invention, the plate member for forming the back plate formed in the rolling step is bent into a ring shape so as to come into contact with the entire lower wall of the flange portion in the bending step. As a result, the corners of the back plate are formed in an R shape, the surface pressure is made uniform over the entire circumference of the joint surface between the cylinder block and the oil pan, and stress concentrates at the corners of the back plate. Can be prevented, and the durability of the oil pan can be improved. Further, the back plate having a predetermined shape can be easily manufactured by the rolling process and the bending process.

According to the third aspect of the present invention, the back plate is flat-pressed by the pressing process after the bending process. Therefore, the thick portion formed by the bending process is crushed to flatten the back plate. As a result, the stress can be more effectively prevented from being concentrated at the corners of the back plate.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a perspective view showing the back plate of the same.

FIG. 3 is a perspective view showing an example of manufacturing the above-mentioned back plate.

4 is a cross-sectional view of the main part of FIG.

5 is an enlarged view of a main part of the back plate of FIG.

FIG. 6 is a diagram showing a manufacturing example for correcting a bent portion of a back plate.

FIG. 7 is a perspective view showing a conventional example of an oil pan mounting device.

FIG. 8 is an enlarged sectional view of the main part of the above.

FIG. 9 is a diagram showing an example of manufacturing a conventional back plate.

FIG. 10 is a diagram for explaining a conventional defect.

[Explanation of symbols]

 11 Cylinder Block 12 Oil Pan 12A Flange 13 Back Plate 14 Round Bar Steel

Claims (3)

[Claims] 1. A cylinder block lower end wall is brought into contact with an upper wall of a flange portion on the outer periphery of an oil pan, and a lower plate of the flange is brought into contact with a flat back plate, and the oil pan is inserted into the cylinder through the back plate. In an oil pan mounting device for an internal combustion engine, which is fastened to a block and fastened by a fastening member, the back plate is formed in a ring shape so as to come into contact with the entire lower wall of the flange portion, and a cross section of the back plate. An oil pan mounting device for an internal combustion engine, characterized in that the corner portion is formed in an R shape. 2. A cylinder block lower end wall is brought into contact with an upper wall of a flange portion on the outer circumference of the oil pan, and a lower plate of the flange portion is brought into contact with a flat back plate so that the oil pan is connected to the cylinder through the back plate. In an oil pan mounting device for an internal combustion engine, which is fastened to a block by a fastening member, when manufacturing the back plate, a round bar steel material is rolled from both sides along the axis thereof to form a back plate. A rolling step for forming a member, and a plate-like member formed by the rolling step,
A method of manufacturing a back plate in an oil pan mounting device for an internal combustion engine, comprising: a step of bending a ring shape so as to be in contact with the entire lower wall of the flange portion. 3. A manufacturing method of a back plate in an oil pan mounting device for an internal combustion engine according to claim 2, further comprising a pressing step of flat-pressing the back plate, the pressing step being performed after the bending step. Method.