JPS646465Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial field of application This invention relates to a manifold joint structure that prevents stress concentration.

Prior Art The conventional manifold joint structure is as shown in Figs. 1a, 1b, and 1c, in which small diameter pipes 1 are bundled and the ends are welded 3.
Then, axial welding 4 was performed on the outer periphery, and then the pipe was fitted into the large diameter pipe 2 and joined by lap fillet welding 5 along the circumference of the end 2a of the large diameter pipe.
In this structure, in order to ensure airtightness of the joints,
As shown in FIG. 1c, the end surface of the large diameter pipe 2a is welded between the axial weld end 4a of the small diameter pipe and the end surface of the small diameter pipe 1a.
In other words, the lap fillet weld 5 is performed so that the length L1 from the end face 1a of the small diameter pipe to the axial weld end 4a is not smaller than the length L2 from the end face 1a of the small diameter pipe to the end face 2a of the large diameter pipe (L1 ≥ L2). However, when an external force is applied to this joint structure to pull the small diameter pipes apart, the load is concentrated on the axial weld 4 between the small diameter pipes, which can cause a crack 6 as shown in Fig. 1d.

Purpose of the invention The purpose of this invention is to provide a manifold joint structure that prevents stress concentration and improves durability.

Structure of the device In order to achieve the above object, this device is a manifold in which the ends of several small diameter pipes are bundled together and fitted into a single large diameter pipe to join them, in which the small diameter pipes that are welded together are fitted into the large diameter pipe deeper than their axial weld length, and the welding of the large diameter pipe and the small diameter pipe is performed at a position between the end face of the small diameter pipe and the axial weld ends of the small diameter pipes, thereby preventing stress concentration at the welded joint.

Embodiments This invention will be described below based on drawings showing embodiments. FIG. 2 and subsequent figures show a manifold coupling structure according to this invention, in which a plurality of small-diameter pipes 1 are bundled and joined to one large-diameter pipe 2. The end of the small diameter pipe 1 is
Perform edge welding 3 and axial welding 4 on the outer circumference,
This end portion is inserted into the large diameter pipe 2, and the small diameter pipe 1 and the large diameter pipe 2 are joined by overlap welding 7. Insertion depth L3
is larger than the axial weld length L1 of the small diameter pipe 1, and the distance L2 from the end surface 1a of the small diameter pipe 1 to the overlap weld 7
is equal to or smaller than the length L1 of the axial weld 4.

3 and 4a, b show embodiments of alternative arrangements of small diameter tubes 1. FIG. Figure 4b is A of Figure 4a.
In the sectional view taken along line -A, the size relationship of L1, L2, and L3 is the same as in FIG. 2. FIG. 5 shows a shape in which the end portion 2a of the large diameter pipe 2 is reinforced. This end portion 2a can provide further strength against external forces acting in the direction of separating the small diameter tubes 1 from each other.

In the manifold coupling structure configured as described above, when an external force acts in the direction of separating the small diameter pipes 1 due to vibration or the like, the end portion 2a of the large diameter pipe 2 bears this load, and the small diameter pipe 1 Stress concentration that would cause cracks in the axial welded portion 4 is not caused, and
The durability of the manifold can be improved. In addition, in the conventional fillet welding 5 at the end 2a of the large diameter pipe 2, the allowable width of the aiming position of the welding wire was narrow, which affected the weld shape and penetration, but in the lap welding 7 of this invention, the welding wire The permissible width of the target position is relaxed, the welding work becomes easier, and the reliability of the welded part can be improved.

Effects of the invention As explained above, this invention can prevent stress concentration at the welded part when an external force is applied in the direction of separating the small diameter pipes in the joint structure of the manifold pipes, thus improving durability. effective. Moreover, the permissible width of the target position of the welding wire is relaxed, which has the effect of improving the reliability of the welded part.

[Brief explanation of the drawing]

Figures 1a-d show conventional manifolds, with the first
Figures a and b are perspective views of a small diameter tube, and Figures 1c and d are a longitudinal cross-sectional view and a side view, respectively, of the manifold coupling structure. Figure 2 and subsequent figures show examples of this invention; Figure 2a is a perspective view of a welded part of a small diameter pipe;
Figure b is a longitudinal sectional view of the manifold coupling structure, Figures 3 and 4 a and b are sectional views showing other arrangements of small diameter pipes, and Figure 5 shows an embodiment of the end of a large diameter pipe. FIG. 1... Small diameter pipe, 2... Large diameter pipe, 4... Axial welding, 7... Lap welding.

Claims (1)

[Scope of utility model registration request] A manifold pipe in which multiple small-diameter pipes are bundled and joined to one large-diameter pipe, and the small-diameter pipes that are welded together are inserted into the large-diameter pipe deeper than the axial weld length of the small-diameter pipes, and the large-diameter pipe is A manifold pipe coupling structure characterized in that welding of a diameter pipe and a small diameter pipe is performed at a position between the end of the small diameter pipe and the mutually axial welded ends of the small diameter pipes.