JPS5926143Y2 - Kannoketsu goukouzo - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a coupling structure, such as an automobile exhaust pipe, to which an input is applied from a certain direction.

A bending moment load is applied to the exhaust pipe of the above-mentioned automobile due to the vibration of the engine, and a large stress is generated.

Further, such bending moment input to the exhaust pipe is applied from a fixed direction, and the generated stress distribution is as shown in FIG.

That is, when a bending moment input is applied to the pipe 1 in the direction A, the generated stress σ is the maximum tensile stress at the lower end of the input, gradually decreases toward the center, becomes zero at the central axis, and gradually increases until the input The compressive stress is maximum at the upper end.

In other words, no stress is generated at the center of the tube 1, but a considerably large stress is generated at the lower input end and the upper end, and the durability of the tube 1 is determined by the durability of these portions.

Methods to improve this durability include, for example, reducing the rigidity of the pipe 1 itself and its system to increase displacement to reduce stress, and increasing the strength of the pipe 1 itself and its system to ensure durability. There are ways to do this.

However, in reality, the pipe 1 is welded to other members such as a muffler, and stress concentration occurs there due to changes in the cross-section of the notch at the welded end at the joint.

In other words, as shown in FIG.
When welded and joined together on the circumference, the material strength near the weld build-up will decrease, stress concentration will occur near point a in input direction A, and the stress level will become greater than the material strength, potentially causing damage to that location. There is.

In other words, the weakest part of the tube 1 is the part where it joins other parts 2, and the strength of the blue system is determined by the strength of the joint, which in turn determines its durability, so to improve durability, the joint must be reinforced. There is a need.

Conventionally, a structure as shown in FIG. 3 has been adopted as a method of reinforcing the joint portion of the pipe 1.

This is the input vertical direction and the direction passing through the center of the tube (hereinafter simply referred to as the "input vertical direction").

) The reinforcing plate 3 protruding from B is applied to the pipe 1 as shown in the figure and welded.The principle is to apply the stress distribution as shown in Fig. 1, and to weld the reinforcing plate 3 protruding from B to The goal is to share more human resources.

In this way, the circumferential welding point a between the tube 1 and the other member 2 will have a double structure with the reinforcing plate 3, and the section modulus will be high and the stress level there will be considerably reduced, so there is no risk of breakage.

In addition, the stress level in the area away from the circumferential welding point a is effectively reduced by the protrusion of the reinforcing plate 3 in the B direction, and the result is as shown in the stress level diagram in Figure 3. High stress areas are eliminated.

Although there is no problem with such conventional methods in terms of reinforcement, since the reinforcing plate 3 used has a complicated shape, forming it requires time and effort, and furthermore, the welding part at the protruding part is long. , and it has the drawback that it requires curved surface welding and cannot be easily performed.

This invention improves and eliminates the above-mentioned conventional drawbacks, and provides a structure in which pipes are joined using a simple semi-cylindrical reinforcing plate.

That is, the present invention has a pair of semicircular reinforcing plates 4 as shown in FIGS. 4 input vertical direction B
This is a joint structure in which the side surface (divided surface) of the tube 1 is welded to the pipe 1, and the circumference of the joint to the other member 2 is also welded.

In other words, the stress level is sufficiently reduced by making the joint part double-structured with semi-cylindrical reinforcing plates 4, which have a higher section modulus than in the case of plain pipe, and welding the sides of the reinforcing plates 4 to the lowest stress level. The aim is to improve the strength of the joint by bringing the vertical direction B to a low level of human effort.

When the stress levels of various parts of the joint structure according to the present invention were actually measured, the results were as shown in the stress level diagram of FIG.

According to this, the stress level distribution generated in the tube 1 (see the solid line graph in Figure 4) is almost the same as in the conventional case shown in Figure 3, and there are no locally high stress areas, eliminating the risk of breakage. I understand.

Further, the stress level distribution on the outer circumferential surface of the reinforcing plate 4 (see the broken line graph in FIG. 4) is lowest in the input vertical direction B, and the effectiveness of welding here becomes clear.

As explained above, the present invention has a pair of semi-cylindrical reinforcing plates that abut the joint between the exhaust pipe and other members from both sides in the direction in which the bending moment of the exhaust pipe acts. The divided surface of the cylindrical reinforcing plate is arranged in a plane perpendicular to the direction of action of the bending moment, and only one end of the pair of semi-cylindrical reinforcing plates on the other member side and the divided surface are connected to the other member and the exhaust. Since the reinforcing plate is welded to the pipe, the reinforcing plate for reinforcing the joint part of the pipe can have a simple semi-cylindrical shape. Therefore, the reinforcing plate can be processed and formed very easily, and the number of man-hours can be reduced.

In addition, since the reinforcing plate is welded to the side surface of the tube at the side surface in the vertical direction of the input (splitting surface) where the stress generated is lowest, there is no problem with the decrease in material strength near the built-up part due to welding. Since welding is performed in a straight line, weldability is significantly improved and workability can be easily improved.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of stress distribution in a typical pipe. Figure 2 is a partial cross-sectional side view showing the state of connection of raw pipes and its stress level diagram. Figure 3 is an example of a conventional pipe connection structure via a reinforcing plate. FIG. 4 is a partial cross-sectional side view and stress level diagram showing an embodiment of the pipe coupling structure according to the present invention, and FIG. 5 is a diagram showing the stress level in FIG. 4. FIG. 3 is an X-ray cross-sectional view. 1...Pipe, 2...Other parts, 4...
...Reinforcement plate, A...Input direction, B...
Input vertical direction.

Claims (1)

[Scope of utility model registration request] The reinforcing plates are a pair of semi-cylindrical reinforcing plates that abut the joint between the exhaust pipe and other members from both sides in the direction in which the bending moment of the exhaust pipe is applied, and the dividing surface of the pair of semi-cylindrical reinforcing plates is is arranged in a plane perpendicular to the direction of action of the bending moment, and only one end of the pair of semi-cylindrical reinforcing plates on the other member side and the dividing surface are welded to the other member and the exhaust pipe. The joint structure of automobile exhaust pipes.