JP3345673B2 - Welding dowel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a joining member for joining a steel portion and a concrete portion to form a composite structure.
The present invention relates to a welding dowel made of metal used by stud welding.

[0002]

2. Description of the Related Art Conventionally, a concrete floor is formed on a beam of a building, an anchor device is buried in a concrete foundation, or a concrete slab is formed on a bridge made of steel. When a steel part and a concrete part are combined to form a steel-concrete composite structure, a metal welding dowel is used as a joining member between the two. Commonly used welding dowels have a shaft, a weld at the tip, and an enlarged head at the rear end. Then, a number of welding dowels are fixedly erected at predetermined intervals on a steel portion by stud welding, and a concrete portion is formed thereon. The enlarged head of the welding dowel has the effect of resisting the tensile stress in the axial direction of the concrete, and the shaft has the effect of resisting the shear stress of the concrete.

[0003] However, the welding dowel in which the cross-sectional area of the shaft portion and the welded portion provided at the end of the welding dowel are the same has a problem in that the support characteristics against shear stress are not sufficient. That is, the characteristics required for the shear stress of the welding dowel are that the welded portion with the steel portion is not broken and that the amount of breaking deformation of the shaft portion is sufficiently large. However, in the above-mentioned welding dowel, if the cross-sectional area of the shaft part is increased to increase the fracture strength of the welded part, the rigidity of the shaft part is increased and the amount of fracture deformation is insufficient, and the concrete part is damaged, such as cracking. Cause. Conversely, if the cross-sectional area of the shaft portion is reduced in order to increase the amount of fracture deformation, the fracture strength of the welded portion is reduced, and the bonding strength between the steel portion and the concrete portion is reduced. To solve such a problem, Japanese Patent Application Laid-Open No. 5-156720 proposes a welding dowel comprising a shaft portion and an enlarged portion (section) having a larger sectional area than the shaft portion.

[0004] This is because, as compared with the shear failure of a welding dowel whose shaft portion has the same diameter up to the lower end, as in the welding dowel shown in FIG. This demonstrates that the proof stress against shearing force is large. That is, in the welding dowel 1 having the same diameter up to the tip of the shaft portion as shown in FIG. 15, the tip of the welding stud is stud-welded to the base material 8 and the welding dowel 1 as shown in FIG. 8 was compared with the one welded. Then, when the proof stress against the shearing force is measured, the characteristics shown in FIG. 14 appear. That is, in the characteristic of the dowel of FIG. 15 shown by the dotted line and the characteristic of the dowel of FIG. 16 shown by the solid line,
In the case of the dowel shown in FIG. 16, the initial rigidity is greatly increased, and the maximum proof stress is slightly increased. Further, the breaking position is the shaft. At the same time, the shear failure becomes a tensile failure, and the failure mode becomes a ductile failure. Since the fracture is a tensile fracture and a shaft fracture, the fatigue resistance is improved. In addition, it turned out that the shear deformation (deformation ability) at the time of destruction is almost the same. Also, in the range where the shearing force is small, the improved dowel of FIG. 16 also has a feature that the amount of deformation is smaller. In the dowel shown in FIG. 15, the shear fracture portion is a welded portion.

[0005]

However, in the welding dowel proposed above, although the supporting property against the shear stress is improved as compared with the conventional one, it requires complicated processing for forming the enlarged portion and the manufacturing cost is high. There's a problem.
Also, there was a limitation on the improvement of the support characteristics due to structural restrictions. Accordingly, an object of the present invention is to provide a welding dowel which has improved support characteristics against shear stress, does not require such complicated processing, and can be easily formed into various support characteristics. Is what you do.

[0006]

SUMMARY OF THE INVENTION Namely, the present invention provides a metallic welding dowels 1 used is stud welding as coupling member for forming the composite structure of the steel part and the concrete part, the shaft portion 2 tip Enlarged part 3 is formed in the part
Is, the enlarged portion 3 is formed to a larger cross-sectional area the shaft portion 2 by combining member 7 otherwise with the shaft portion 2, before
A reduced portion 4 having a smaller cross-sectional area at the tip of the enlarged portion 3
Is provided, impact the reduced portion 4 from the tip of the enlarged portion 3
The amount that is output is substantially all during the stud welding.
It is a welding dowel configured so that the reduced portion 4 is melted .

[0007]

According to the welding dowel of the present invention, by providing an enlarged portion having a larger cross-sectional area than the shaft portion, the welded portion is not destroyed against the expected maximum shear stress, and the amount of fracture deformation of the shaft portion is reduced. This has the effect that it can be made sufficiently large. Furthermore, since the cross-sectional area of the enlarged portion is larger than that of the shaft portion by combining the shaft portion and other members, it is possible to efficiently manufacture the device at low cost without requiring complicated processing. Only
Also, welded dowel of the present invention are those small reduction unit 4 cross-sectional area than the distal end of the enlarged portion 3 is provided 且
The amount by which the reduced portion 4 protrudes from the tip of the enlarged portion 3 is configured such that the reduced portion 4 is substantially completely melted during stud welding. With this configuration, the breakdown strength of the welded portion can be improved while maintaining a small welding current during stud welding.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
FIG. 1A is a front view of an example of the welding dowel of the present invention, partially cut away, and FIG.
It is sectional drawing. The welding dowel 1 has a shaft portion 2 made of a metal material such as a steel rod, and an enlarged portion 3 having a larger cross-sectional area on the outer periphery of the tip portion. That is, another member 7 having a stepped cylindrical shape (cap shape) having a lower end closed and different from the shaft portion 2 is fitted to the outer periphery of the distal end portion of the shaft portion 2, and both members are fixed by spot welding, fitting, bonding or the like. Thus, an enlarged portion 3 having a larger sectional area than the shaft portion 2 is formed. In the case of fitting or bonding, a part of the outer circumference or the entire circumference is swaged to form another member 7.
The stud welding can be performed more stably by bringing the shaft part 2 and the shaft part 2 into close contact with each other. According to the experiment, if there is uneven contact between the two, a large amount of welding current flows to the contact side during stud welding, and a small amount of welding current flows to a portion having a gap between the two. As a result, it was found that the melted portion of the end of the dowel was biased.

Therefore, in the embodiment of FIG. 1, in order to improve the adhesion between the shaft portion 2 and the other members 7, the lower end portion of the cap has a reduced radius at a position 90 degrees apart from each other. The outer periphery is swaged to form a swaged part 12,
Both parts are tightly fixed uniformly over the entire circumference. Enlargement part 3
The lower and bottom portions are portions to be melted by stud welding, that is, welded portions, and the other member 7 covers the entire surface of the welded portions. The end face of the welded portion may be flat as shown in the figure, but may have a shape whose radius decreases toward the tip, for example, an arc cross section having an arc shape, a triangle shape, or a trapezoid shape. A hemispherical concave portion is formed in the center of the bottom portion of the welded portion, and a spherical flux 6 made of, for example, aluminum is driven into the concave portion and fixed.

The other member 7 can be made of the same steel material as the shaft portion 2. A head 5 having a larger cross-sectional area than the shaft 2 is welded or integrally formed at the rear end of the shaft 2.

The shaft portion 2, the enlarged portion 3, the reduced portion 4, and the head portion 5 are formed in a shape of a rotating body with respect to the axis. However, the outer shape of the other member 7 can be selected as the shape of the enlarged portion 3. As an example, the head 5 can be rectangular or polygonal. The ratio of the diameter to the length of the shaft 2 is 1:
It is about 3.5 to 1:15. The ratio of the diameter of the shaft portion 2 to the diameter of the enlarged portion 3 is about 1: 1.2 to 1: 2.0, and the ratio of the diameter of the enlarged portion 3 to the length (height) of the enlarged portion is 1 :
It is about 0.5 to 1: 1.5.

Further, the height of the reduced portion 4 is such that it is completely melted during stud welding. For example, the diameter of the shaft portion 2 is about 10 to 19 mm, and the diameter of the enlarged portion 3 is 13 to 13 mm. In the case of 23 mm, the height of the reduced portion 4 is 4 mm
And its diameter is about 11 to 20 mm. The welding current at that time is 800 to 1700 amps, and the welding time is about 0.7 seconds to 1.1 seconds. According to the experiment, it was found that the provision of the reduced portion 4 can reduce the welding current of the stud welding. That is, comparing the respective welding currents of the case where the enlarged portion 3 exists to the tip and the case where the reduced portion 4 is provided at the tip of the enlarged portion 3, the diameter of the enlarged portion 3 is in the range of 13 to 23 mm and It was found that when the diameter of the shaft portion 2 was 10 to 19 mm and the diameter of the reduced portion was 11 to 20 mm, the welding current from 100 to 200 amperes was reduced. However, the welding time becomes longer by about 0.1 second.

As a result, it has been found that the provision of the reduced portion 4 allows a small power supply capacity for welding. Note that the diameter and the length of the head 5 are not essential for the present invention, and may be appropriately set.

FIG. 2A is a front view showing another example of the welding dowel of the present invention, partially cut away, and FIG. 2B is a sectional view taken along line BB of FIG. 2A. 2 differs from the example shown in FIG. 1 in that the enlarged portion 3 is shortened and the remaining portion is reduced, and that the swaging portion 12 is formed in a streak shape parallel to the axis. The other parts are the same, and the same parts are denoted by the same reference numerals. Since the reduced portion 4 extends the shaft portion 2 integrally, the reduced portion 4 is naturally made of the same diameter and the same material as the shaft portion 2. By making the cross-sectional area of the reduced portion 4 smaller than that of the enlarged portion 3 in this way, the discharge current of the welding machine can be reduced to a low value during stud welding.
In this respect, the embodiment of FIG. 1 has the same effect. The height of the reduced portion 4 is about 3 to 5 mm.

FIG. 3 is a partially cutaway front view showing a state in which the welding dowel 1 shown in FIG. 1 is stud-welded to the steel portion 8. It is welded upward from the welded portion to the middle of the enlarged portion 3. Therefore, the lower portion of the other member 7 forming the enlarged portion 3 is melted together with the shaft portion 2 and the steel portion 8 around the shaft portion 2 and is firmly joined, so that a sufficient resistance to shear stress is secured. FIG. 4 is a front view showing another example of the welding dowel of the present invention, in which the assembled state is partially cut away, and FIG. 2 is a front view showing the state of FIG. In this example, the enlarged portion 3 is formed by a combination of a portion in which the outer diameter of the shaft portion 2 is enlarged and extended and a bolt hole 10 is formed at the center thereof and a stud bolt 9 portion screwed into the bolt hole. Is formed. The stud bolt 9 corresponds to another member 7 other than the shaft portion 2 in the present invention.

The welding dowel 1 shown in FIG. 4 is obtained by stud welding a stud bolt 9 to a steel portion 8 in advance as shown in FIG. 4 and screwing the remaining shaft 2 and the like to the steel portion 8 as shown by an arrow. 8 and assembly of the welding dowel can be performed in parallel. Alternatively, the stud bolt 9 may be screwed into the bolt hole 10 in advance to assemble a welding dowel, and then stud-welded to the steel portion 8. By expanding the outer diameter of the lower end of the shaft portion 2 and providing a bolt hole at the center of the bottom surface in this manner, the breaking strength of the welding dowel against shearing or bending stress can be sufficiently ensured. Since this welding dowel can reduce the welding area, the influence of welding heat on the steel part is also small.

FIGS. 6 and 7 show another embodiment of the present invention.
The inner diameter of the fitting hole 14 is 0.1 m with respect to the outer diameter of the shaft 2.
m, and the shaft 5 is pressed into the fitting hole 14 by pressing the head 5 in the direction of the arrow to obtain a welding dowel shown in FIG. FIG. 8 is a sectional view taken along line AA of FIG. Next, FIG. 9 shows that the fitting hole 14 formed at the lower end portion of the collar 13 is smaller than the outer diameter of the shaft portion 2 by about 0.05 mm, and the other middle and upper insertion holes 15 are The inner diameter is set to be larger than the outer diameter of No. 2 by about 0.05 mm. Then, while the shaft portion 2 is mounted in the insertion hole 15, an axial pressure is applied to the shaft portion 2 to press-fit the shaft portion 2 into the fitting hole 14. In the embodiment shown in FIGS. 6 to 9, at least one of the outer periphery of the shaft portion 2 and the fitting hole 14 of the collar 13 is coated with amorphous powder for causing diffusion welding, and both are press-fitted. Is preferred. The amorphous powder can be integrally diffusion-welded and fixed between the shaft portion and the collar by heating during the stud welding.

Next, FIGS. 10 and 11 are explanatory views for manufacturing still another dowel of the present invention. That is, the shaft portion 2 is press-fitted into the collar 13 while a hard wire material 20 having a triangular cross section and having a hardness is applied to the outer periphery of the tip portion of the shaft portion 2. Next, FIGS. 12 and 13 are explanatory views showing a method for manufacturing a dowel of another embodiment of the present invention. In FIG. The slits 19 are arranged at intervals of 90 °, and the outer periphery is plastically deformed by applying an external force so that the inner diameter is reduced.
Then, the inner diameter of the plastic deformation portion is set smaller than the outer diameter of the shaft portion 2. In this state, the shaft portion 2 is press-fitted into the collar 13, and the collar 13 and the shaft portion 2 are brought into close contact with each other in the plastic deformation portion. Note that the shaft 2 may be attached to the collar 13 without plastically deforming the tip of the collar 13, and then one end of the collar 13 may be plastically deformed and then crimped to the shaft 2.

[0019]

The present invention has the above-mentioned structure,
The welded portion is not destroyed for the expected maximum shear stress, and the enlarged portion is combined with the shaft and other members so that the cross-sectional area is larger than the shaft, so complicated processing is not required, It can be made efficiently at low cost and
While maintaining a low welding current during tod welding,
The breaking strength can be improved for a minute.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of an example of a welding dowel of the present invention.

FIG. 2 is a front view showing another example of the welding dowel of the present invention, partially cut away.

FIG. 3 is a front view showing a state where the welding dowel 1 shown in FIG.

FIG. 4 is a front view of another example of the welding dowel of the present invention, showing a partially assembled state of the welding dowel.

5 is a front view showing a state after assembling the welding dowel from the state shown in FIG. 4 and partially cutting out a state after welding to a steel part.

FIG. 6 is an explanatory view of a manufacturing process of still another embodiment of the welding dowel of the present invention.

FIG. 7 is a longitudinal sectional view of a main part of the welding dowel.

FIG. 8 is a sectional view taken along line AA of FIG. 7;

FIG. 9 is an explanatory view of a manufacturing process of still another embodiment of the welding dowel of the present invention.

FIG. 10 is an explanatory view of a manufacturing process of still another embodiment of the welding dowel of the present invention.

FIG. 11 is a sectional view taken along line BB of FIG. 10;

FIG. 12 is an explanatory view of a manufacturing process of still another embodiment of the welding dowel of the present invention.

FIG. 13 is a partial longitudinal sectional view of the welding dowel.

FIG. 14 shows another conventional welding dowel shown in FIG. 15 and FIG.
7 is a fracture characteristic curve of shear force and slip with a welding dowel shown in FIG.

FIG. 15 is a cutaway explanatory view of another conventional welding dowel.

FIG. 16 is an explanatory view of a fracture of a welding dowel in which the lower end of the shaft is enormous.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Welding dowel 2 Shaft part 3 Enlarged part 4 Reduction part 5 Head 6 Flux 7 Other members 8 Steel part 9 Stud bolt 10 Bolt hole 11 Notch 13 Collar 14 Fitting hole 15 Insertion hole 19 Slit 20 Wire material

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-96375 (JP, A) JP-A-62-267087 (JP, A) Jikai Sho 56-65779 (JP, U) (58) Investigation Field (Int.Cl. ⁷ , DB name) E04B 1/48

Claims (1)

(57) [Claims] 1. A metal welding dowel 1 which is used by being stud-welded as a connecting member when forming a composite structure of a steel part and a concrete part, wherein an enlarged part 3 is formed at the tip of a shaft part 2, The enlarged portion 3 is formed to have a larger sectional area than the shaft portion 2 by combining the shaft portion 2 and the other members 7, and a reduced portion having a smaller sectional area than the distal end portion of the enlarged portion 3.
The amount by which the reduced portion 4 projects from the tip of the enlarged portion 3 is
Substantially all of the reduced portion 4 is melted during the stud welding.
Welding dowel configured to melt .