JPH0227127Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] The invention relates to an oil pan structure made of damping steel plate.
In particular, the present invention relates to an oil pan structure that improves the sealability and durability of the peripheral edge of a drain hole formed through the bottom of an oil pan body.

[Technical background of the invention and its problems] In order to reduce vibrations and prevent noise in oil pans used in internal combustion engines, the oil pan body is made of a vibration-damping steel plate made by laminating two or more steel plates with a resin layer interposed between them. Proposals have been made to mold.

However, it is necessary to form a drain hole in the bottom of the oil pan, and if the drain hole 2 is formed in the bottom of the oil pan body 1 as shown in FIG. There is a problem in that oil enters the interior through the joint gap between 3a and 3b, melts the interposed resin layer 4, and causes the jointed steel plates 3a and 3b to separate from each other, resulting in deterioration of vibration damping performance and strength. be. For this reason, as shown in FIG.
However, since the welding heat generates pyrolysis gas from the resin layer 4, the weld seal 5 is formed by a weld bead full of bubbles, which poses problems in terms of strength and airtightness. It was hot.

[Purpose of the invention] The present invention was devised to effectively solve the problems of the above-mentioned conventional technology, and its purpose is to improve the sealing performance and durability of the drain hole periphery with a simple structure. The purpose is to provide an oil pan structure.

[Summary of the invention] In order to achieve the above object, the invention forms a drain hole in the bottom of the oil pan body, which is made of damping steel plates with a resin layer between the steel plates, and a drain hole is formed on the back side of the drain hole. The drain sheet of the drain plug is brought into contact with this so as to cover this, and the peripheral edge of the drain hole of the inner steel plate in contact with this sheet is welded without covering the resin layer, and the welded part and the drain hole of the outer steel plate are welded. It is made by covering the peripheral edges with a resin layer and welding it, and the pyrolysis gas from the resin layer is emitted during the first welding.
Since the weld bead has a structure that does not contain air bubbles, the durability and sealing performance of the peripheral edge of the drain hole are improved.

[Embodiment of the invention] An embodiment of the invention will be described below in detail based on the accompanying drawings.

In FIGS. 4 and 5, 1 is an oil pan body of an internal combustion engine, which is formed by pressing a damping steel plate 3 with a resin layer 4 interposed between two thin steel plates 3a and 3b. has been done. A drain hole 2 is formed through the bottom of the oil pan body 1,
A drain sheet 6 is seated on the back side of the drain hole 2 so as to cover it, and is fixed liquid-tightly by arc welding. In particular, this welding is performed by first forming a weld between the open end of the inner steel plate 3a in contact with the drain sheet 6 and the drain sheet 6, as shown in FIG. Seal part (this is also called the first seal part)
10, and then, as shown in FIG. 11. That is, the drain sheet 6 is welded to the periphery of the drain hole 2 so that the inner periphery of the drain hole 2 has welded seal portions 10 and 11 that overlap in stages for each steel plate 3a and 3b.

In addition, when performing this welding, spot welds 12 are preliminarily placed between the steel plates 3a and 3b at the peripheral edge of the drain hole at appropriate intervals in the circumferential direction so as to surround the drain hole 2.
may be formed to prevent separation between the steel plates 3a and 3b.

The drain sheet 6 has a nut portion 6a for screwing a drain plug 7 made of a bolt, and the shaft hole of this nut portion 6a substantially forms a drain hole. In particular, the nut portion 6a is configured to pass through the drain hole 2 and protrude to the outside, and the head flange surface 7a of the drain plug 7 is seated on the protruding end thereof via the packing 13.

According to the above configuration, the welded seal parts 10 and 11 that seal between the steel plates 3a and 3b are formed on the inner peripheral part of the drain hole 2, so that the steel plates 3a and 3b are sealed.
It is possible to prevent oil, water, etc. from entering between a and 3b, and it is possible to improve vibration damping performance and strength. In particular, since the welded seal parts 10 and 11 are formed in two stages, the first seal part 1
0, the resin layer 4 is formed by welding heat.
Most of the pyrolysis gas generated from the steel plates 3a and 3b
Even if the second seal portion 11 is formed, the weld bead will not contain any air bubbles. Therefore, the welded seal portion 10,
The strength and airtightness of the drain hole 2 are improved, and the sealability and durability of the peripheral edge of the drain hole 2 are ensured.

Further, as in the embodiment, the nut portion 6a of the drain sheet 6 is made to protrude outside from the drain hole 2, and the head flange surface 7a of the drain plug 7 is seated on the protruding end. Even if it is over-tightened, it will not cause the peripheral edge of the drain hole to collapse and deform as shown in FIG. 2, causing a crack 9 near the projection weld 8.

Incidentally, as shown in FIG. 7, the drain hole 2 may be enlarged so that the head flange surface 7a of the drain plug 7 is seated on the drain seat 6, thereby allowing the nut portion 6a to be removed from the drain hole 2 to the outside. It exhibits the same effect as above without making it stick out.

[Effects of the invention] In summary, the present invention provides the following excellent effects.

(1) The drain sheet and the peripheral edge of the drain hole on the inner steel plate in contact with this are welded without covering with a resin layer, and the welded area and the peripheral edge of the drain hole in the outer steel plate are covered with a resin layer and welded. Since the structure is welded in two stages, the pyrolysis gas from the resin layer is exhausted during the first welding, resulting in a welded seal structure that is airtight and strong, with no air bubbles in the weld bead. The durability and sealing properties of the drain hole periphery are improved.

(2) The disadvantages of oil pans made of vibration-damping steel plates can be solved all at once with a simple structure in which the welded seal part is structured in stages, and has extremely high practical value.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the conventional oil pan structure.
Fig. 2 is an enlarged cross-sectional view of the same, Fig. 3 is a partial cross-sectional view showing another conventional example, Fig. 4 is a cross-sectional view showing an embodiment of the present invention, and Fig. 5 is a cross-sectional view taken along line A-A in Fig. 4. FIG. 6 is a partial sectional view showing a welded seal portion, and FIG. 7 is a sectional view showing a modified embodiment of the present invention. In the diagram, 1 is the oil pan body, 2 is the drain hole, and 3
3 is a damping steel plate, 3a and 3b are steel plates, 6 is a drain sheet, 7 is a drain plug, and 10 and 11 are welded seal parts.

Claims (1)

[Scope of utility model registration request] A drain hole is formed in the bottom of the oil pan body, which is made of a damping steel plate with a resin layer between the steel plates, and a drain sheet of a drain plug is brought into contact with the back side of the drain hole so as to cover it. The sheet and the peripheral edge of the drain hole of the inner steel plate in contact with the sheet are welded without covering with a resin layer, and the welded part and the peripheral edge of the drain hole of the outer steel plate are covered with a resin layer and welded. Characteristic oil pan structure.