JPH101068A - Member joining structure for framed vehicle body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a member joining structure for a framed vehicle body capable of suppressing deformation of a frame construction vehicle body caused by its thermal distortion at welding and ensuring its enhanced dimensional accuracy in manufacturing the body from hollow members as its main structural members. SOLUTION: A member joining structure comprises a side roof rail 1, a pillar outer member 4 and a pillar inner member 5. The side roof rail 1 is formed hollow integrally with flanges 2 and 3. The pillar outer and inner members 4 and 5 are fixed on the side roof rail 1 as to sandwich the same therebetween and are joined together by plug welds 7 and 8 and by a resistance spot weld by way of the flange 2. The plug welds 7 and 8 are located on a neutral axis 10 and are roughly symmetrized in their pair of weld points opposed to each other with respect to a centroid 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle body having a frame structure which is mainly assembled by melt welding using a hollow member as a main structural member, and largely suppresses deformation of the vehicle body due to thermal distortion during welding. The present invention relates to a member connecting structure of a frame body suitable for securing a high vehicle body dimensional accuracy.

[0002]

2. Description of the Related Art Conventionally, an automobile body has been assembled by joining parts having a hollow closed cross-sectional shape formed by press working by resistance spot welding. However, in recent years, the frame body structure using a hollow member as a main skeleton member of the vehicle body has been increasing in order to reduce the weight by reducing the thickness, to improve the strength by integrating parts, and to increase the assembly efficiency. FIG. 12 shows one example, and shows the left half of the frame body 100. A center pillar 1 is attached to a side roof rail 101 which is a hollow member made of an extruded aluminum material.
02 is fusion-welded. Roof 1 which is an outer panel
Reference numeral 03 is joined to the side roof rail 101 by resistance spot welding.

FIG. 13 is a cross-sectional view taken along the line AA of FIG. 12, and the coupling structure will be described in detail. The side roof rail 101, which is a long hollow member, is sandwiched by a center pillar 102. And the center pillar 102 is a pillar outer 1
04 and a pillar inner 105. That is, the pillar outer 104 is attached to the side roof rail 101.
And the pillar inner 105 are respectively overlapped, and the flange 106 of the side roof rail 101 and the pillar outer 104
The pillar inner 105 and the pillar inner 105 are joined by resistance spot welding 111, and the pillar outer 104 and the pillar inner 105 are joined by resistance spot welding 112.

[0004] On the other hand, since the side roof rail 101 has a hollow shape, resistance spot welding cannot be applied to welding the hollow portion of the side roof rail 101 to the pillar outer 104 and the pillar inner 105. 110 and the like. The roof 103 is connected to the side flange 107 of the side roof rail 101 by resistance spot welding 113. FIG. 14 shows FIG.
3 is a side view in the direction of arrow B of FIG.
4, a plurality of plug weldings 110 as axial weldings of the side roof rails 101 as shown in FIG.
It is connected to the side roof rail 101. Also, the pillar inner 105 is connected to the side roof rail 101 by a plurality of plug weldings (not shown) in substantially the same manner.

[0005]

However, in such a conventional member connecting structure, since the main structural member has a hollow shape, resistance spot welding which causes little welding distortion cannot be applied. For this reason, as described above, the center pillar 102 is connected to the side roof rail 101 using fusion welding such as plug welding 110, but the welding distortion is large, and the side roof rail 101 has a structure shown in FIG. Welding distortion (δ) occurs due to a large angular deformation. As a result, in order to reduce the dimensional accuracy of the vehicle body or to secure the desired dimensional accuracy of the vehicle body, it is necessary to perform deformation correction processing or the like after welding, which is extremely troublesome and reduces production efficiency. was there.

[0006] The present invention has been made in view of the above-mentioned problems of the prior art.
Using a hollow member as a main structural member, when manufacturing a frame structure body mainly assembled by fusion welding, greatly suppresses deformation of the body due to thermal distortion during welding,
It is an object of the present invention to provide a member connecting structure of a frame body suitable for securing good vehicle body dimensional accuracy.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, by appropriately controlling the welding position between the hollow member and the member to be joined,
The inventors have found that the above problems can be solved, and have completed the present invention. That is, the member connecting structure of the frame body according to claim 1 of the present invention has a hollow elongated first member and is tightly fitted to the first member, and is welded from the outside to the axial direction of the first member. And a second member joined substantially at right angles to each other, wherein a welding position of the first member and the second member is an arbitrary cross section orthogonal to an axial direction of the first member. Is characterized by being arranged at a position substantially point-symmetric with respect to the centroid in.

According to a second aspect of the present invention, at least one pair of the welding positions is disposed substantially on a neutral axis in the cross section orthogonal to the axis. Further, the member connecting structure of the frame body according to claim 3 is characterized in that at least one pair of the welding positions is disposed at a position substantially symmetrical with respect to the neutral axis in the cross section orthogonal to the axis.

Further, the member connecting structure of the frame body according to claim 4 is characterized in that the first member is made of an extruded member made of an aluminum alloy. Further, the member connecting structure of the frame body according to claim 5 is characterized in that the first member is a bulge molded product or a roll molded product made of a steel pipe or a steel plate, or a composite molded product combining these. Still further, the member connecting structure of the frame body according to claim 6 is characterized in that a discard bead without member connecting is arranged in at least one of a plurality of pairs of the welding positions.

[0010]

According to the first aspect of the present invention, the welding position of the first member and the second member is substantially point-symmetric with respect to the center of the first member in a cross section perpendicular to the axis. Controlled. Therefore, deformation of the vehicle body due to thermal distortion at the time of welding of a frame-structured vehicle body mainly assembled by fusion welding can be largely suppressed, and good vehicle body dimensional accuracy can be secured without performing deformation correction after welding.

According to the second aspect of the present invention, at least one pair of the welding positions is disposed substantially on the neutral axis in the cross section orthogonal to the axis. Therefore, since the welding line by the welding performed at such a welding position is always present on the neutral axis, the welding deformation force does not act in the direction in which the first member undergoes angular deformation, and the distortion due to the angular deformation during welding is reduced. It can be greatly suppressed. According to a third aspect of the present invention, at least one pair of the welding positions is arranged at a position substantially axially symmetric with respect to the neutral axis. Therefore,
Since the welding deformation between the outer side and the inner side of the first member, which is a hollow member, is offset, distortion due to angular deformation during welding can be significantly suppressed.

According to the fourth aspect of the present invention, the first member is formed of an extruded aluminum alloy.
Therefore, a lightweight hollow member having a complicated sectional shape can be easily used, and a lightweight aluminum frame body having desired dimensional accuracy can be obtained. In the member connecting structure of the frame body according to the fifth aspect, the first member is formed from a bulge molded product or a roll molded product made of a steel pipe or a steel plate. Therefore, a molded article made of a steel pipe with a low material cost can be used as the hollow member, and it can be partially applied to a conventional monocoque body, so that a steel body with low cost and high strength and rigidity can be obtained.

According to the sixth aspect of the present invention, a discard bead which is not involved in the joining of the members is arranged at at least one of a plurality of pairs of welding positions. Therefore, even on the side where there is no member to be welded, the same strain suppression effect as described above can be obtained by disposing the discard bead at a predetermined position, thereby greatly improving the design flexibility of the joint structure. Can be.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to embodiments with reference to the drawings. (Embodiment 1) FIG. 1 is a cross-sectional view of a member connecting structure of a frame body showing an embodiment of the present invention. In FIG. 1, a side roof rail 1 is formed integrally with a flange 2 and a side flange 3 by using an extruded aluminum material, and has a hollow shape. In addition, the pillar outer 4 and the pillar inner 5 are overlapped in a manner tightly attached to the side roof rail 1 in the same manner as in the conventional example, and the plug welds 7 and 8 and the flange 2 are formed.
Through resistance spot welding (not shown). Further, the roof 6 is joined to the side flange 3 of the side roof rail 1 by resistance spot welding similarly to the conventional example.

In this embodiment, the positions of the outer-side plug weld 7 and the inner-side plug weld 8, which are the axial welding of the side roof rail 1, are determined in the vertical direction in a cross section orthogonal to the axis of the side roof rail 1. 14, that is, on the neutral axis 10 against bending stress as shown in FIG. I have.

When the plug welding position is below the neutral axis of the hollow member as in the conventional example (FIG. 13), the angular deformation of the hollow member becomes upwardly convex, and conversely, the plug welding position is changed. If it is above the neutral axis, the angular deformation is convex downward. On the other hand, in the present embodiment, since the positions of the plug welds 7 and 8 in the axial direction are arranged on the neutral shaft of the hollow member as described above, it is possible to avoid the deformation force from acting in the angular deformation direction. Thus, angular deformation due to welding distortion can be almost completely prevented.

In the member connecting structure of the present embodiment, as in the conventional example, plug welding in which a plurality of pilot holes having a predetermined diameter are formed in the upper plate side and point-like arc welding is performed is an example of a welding method. The same effect can be obtained by using MIG spot welding, which is an arc welding that does not require pilot hole machining, and because MIG spot welding does not require pilot hole machining like plug welding. , And the productivity can be further improved. Further, for example, as shown in FIG. 2, the fillet arc welding 11 is continuously or intermittently performed in the axial direction of the side roof rail 1 on the plate end of the upper plate (the pillar outer 13 or the pillar inner 14 in the present embodiment). The same effect can be obtained even if 12 is applied.

(Embodiment 2) FIG. 2 shows another embodiment. In FIG. 2, a pillar outer 13 and a pillar inner 14 are superimposed on a side roof rail 1 made of an extruded aluminum material as a hollow member so that respective plate ends are located near a neutral axis 10 of the side roof rail 1. The positions of the fillet arc welds 11 and 12 are located on the neutral axis 10, and are arranged substantially in point symmetry so that the pair of welds face the centroid 9.

Generally, in fillet arc welding, particularly when continuous welding is performed, the joining strength of members is higher than that of plug welding which is point-like welding, but the length of the welding line is longer. , Welding deformation also increases. However, in the present embodiment, as described above, the position of the welding line of the fillet arc welding is on the neutral shaft 10 in the vertical direction of the side roof rail 1 and the pair of weldings are opposed to each other in the centroid 9. On the other hand, since they are arranged at substantially point symmetrical positions, no deformation force acts in the direction of angular deformation as in Embodiment 1, angular deformation due to welding distortion can be almost completely prevented, and high bonding strength can be obtained. There is an effect that it can be obtained. In addition, in the case of fillet arc welding, there is an advantage that productivity is improved because a prepared hole is not required unlike plug welding.

FIG. 3 shows a JIS-A6 as a material of the side roof rail 1 in the connection structure shown in FIG.
N01-T5 material, pillar outer 13 and pillar inner 1
4 shows the results of measuring the amount of angular deformation due to welding distortion by using JIS-A5182 as the material and changing the position of the fillet arc welding in various ways. The welding position changes the distance (α) between the neutral axis of the hollow member and the weld as shown in FIG. 13, and the amount of deformation is set at the center of the entire length L of the hollow member in the axial direction as shown in FIG. The maximum angular deformation (δ) when continuous fillet arc welding with a welding line length of 290 mm was performed was measured. As shown by "O" in FIG. 3, when the welding position is 0, that is, when the welding position is on the neutral axis of the hollow member as in the present invention, almost no angular deformation occurs, whereas the welding position is the neutral axis. It was evident from the test results that the greater the distance from the surface, the greater the amount of angular deformation (δ).

(Embodiment 3) FIG. 4 shows another embodiment. In FIG. 4, a pillar outer 15 and a pillar inner 16 are overlapped on a side roof rail 1 made of an extruded aluminum material. It extends to above 10. Then, plug welding 17 and 18 are performed, respectively. In the present embodiment, the positions of the plug welds 17 and 18 are relative to the vertical axis 10 of the side roof rail 1 with respect to the plug weld 1, 18.
Reference numeral 7 denotes a lower position, and a plug weld 18 is located at an upper position.

In FIG. 4, since the position of the plug weld 17 on the pillar outer 15 side is below the neutral shaft 10, angular deformation occurs in the direction that makes the side roof rail 1 convex upward as described above. Let it. On the other hand, the plug welding 18 on the pillar inner 16 side is angularly deformed in such a direction as to make the side roof rail 1 convex downward since the welding position is above the neutral shaft 10. Accordingly, the deformation of the plug weld 17 on the pillar outer 15 side and the plug weld 18 on the pillar inner 16 side are offset by each other, so that almost no permanent deformation finally remains on the side roof rail 1. Therefore, an effect that welding distortion can be significantly reduced can be obtained.

In FIG. 4, instead of plug welding, fillet arc welding is performed in the same manner as in the second embodiment.
The welding position on the side is a distance (β) from the neutral shaft 10 of 25 m.
The result of measuring the amount of angular deformation (δ) under the same conditions as in Embodiment 2 is indicated by “●” in FIG. From the test results,
Deformation due to the welding on the pillar outer 15 side and the welding on the pillar inner 16 side are offset each other, and the effect that the angular deformation of the side roof rail 1 can be significantly reduced was confirmed. Desirably, with respect to the centroid, in the case of a section not having a line symmetrical shape in which the second moment of area is different for each of the outer side and the inner side with respect to the centroid, the positions should be such that the respective welding deformation amounts are equivalent. It is ideal to arrange the welding positions, but practically, there is almost no problem if the positions are almost point-symmetric with respect to the centroid.

(Embodiment 4) FIG. 5 shows still another embodiment. In FIG. 5, a pillar outer 15 and a pillar inner 16 are superimposed on a side roof rail 1 made of an extruded aluminum material.
Is stopped below the neutral shaft 10 and the pillar inner 16
In the above-described embodiment, the plug welding 17 on the pillar outer 15 side and the plug welding 18 on the pillar inner side are arranged at positions facing the centroid 9. Is the same as

In this embodiment, in addition to the above configuration, another row of plug welds 19 is added to the pillar inner 16 side.
The pillar inner 16 is connected to the side roof rail 1 by two rows of plug weldings 18 and 19. On the other hand, at a position facing the center 9 of the plug weld 19 on the pillar inner 16 side, that is, at a point symmetrical position, a so-called discard bead 20 without member connection is arranged. This discarded bead 20 has a weld bead disposed on the outer wall of the side roof rail 1 and does not fulfill the function of joining members. The roof 6 is connected to the side roof rail 1 by resistance spot welding 113 as in the conventional example. In the present embodiment, the plug welding 17
And 18 and the positions of the plug weld 19 and the discard bead 20 are arranged at positions opposing the centroid 9 of the side roof rail 1, that is, substantially point-symmetric positions.

In the case of this embodiment, the angular deformation direction of the side roof rail 1 is opposite to that of the plug weld 17 on the pillar outer 15 and the plug weld 18 on the pillar inner 16 at a position facing the center of gravity 9. Therefore, in addition to canceling the deformation, the deformation caused by the plug weld 19 on the pillar inner 16 side and the discard bead 20 at a position opposed to the plug weld 19 is also canceled.
Therefore, as a result, almost no permanent distortion is finally left on the side roof rail 1, and therefore, similar to the above-described embodiment,
The effect of greatly reducing welding distortion can be obtained.

In this embodiment, as described above,
The plug weld 17 and the plug weld 18 and the plug weld 19 and the discard bead 20 are arranged at point symmetric positions with respect to the centroid 9, respectively. To the plug welding 17
It is needless to say that the same effect can be obtained even when the configuration in which the discard bead 20 and the plug weld 18 and the plug weld 19 are respectively disposed at the axially symmetric positions is obtained. In the present embodiment using the discarded beads, it is possible to provide a single row or a plurality of rows of discarded beads 20 at any position where the deformation can be canceled regardless of the presence or absence of the parts to be welded. The degree of freedom in the design of the part can be greatly improved, and there is an effect that the practicality is high.

(Embodiment 5) FIG. 6 shows still another embodiment of the member connecting structure of the present invention. This embodiment has substantially the same configuration as the first embodiment (FIG. 1), but uses steel as a material, and shows an example of application to a steel plate wheel.
In FIG. 6, the side roof rail 21 of the frame body is shown.
Is formed integrally with the flange 26 from a steel tube tube such as a structural steel tube or a high-strength steel tube or from a rolled steel plate by hydraulic bulge forming, roll forming, or a combination of these processes to form a hollow shape. doing.

The pillar outer 22 and the pillar inner 23 are also formed from a rolled steel plate, and are superposed on the side roof rail 21 and joined by plug welding 24 and 25.
The roof 27 is also joined to the flange 26 of the side roof rail 21 by resistance spot welding 28 or the like. Also in the present embodiment, plug welding 24 on the pillar outer 22 side and plug welding 2 on the pillar inner 23 side are performed.
The position 5 is located on the neutral shaft 10 in the vertical direction in the cross section of the side roof rail 21 in the direction perpendicular to the axis, and is disposed substantially point-symmetric with respect to the centroid 9 of the side roof rail 21. Similarly to the case described above, no deformation force acts in the direction of angular deformation, and angular deformation due to welding distortion can be almost completely prevented.

In the present embodiment, steel such as a steel pipe or a rolled steel sheet is used as a material, and hydraulic bulge forming, roll forming or a combination thereof is used from a steel pipe tube such as a structural steel pipe or a high-tensile steel pipe or a rolled steel sheet. Since the hollow member is formed by a simple processing means, the effect of reducing the weight is less than in the case of using the aluminum alloy in the above embodiment, but the material cost is low, and not only the frame body but also the conventional monocoque is used. The effect that partial application can be easily applied to a steel plate body is obtained.

Further, since the material is steel, the welding method is not limited to plug welding, but also has the effect of expanding the choice of welding methods such as fillet arc welding, plasma welding, plasma spot welding, and laser welding. is there. In addition,
Even when a steel side roof rail is used as in the present embodiment, the same configuration as in the various embodiments using the side roof rail made of extruded aluminum as described above may be adopted. Needless to say.

(Embodiment 6) Still another embodiment will be described. First, as another conventional example, as shown in FIG. 7, a member connecting structure of a frame body in which a bracket 31 is connected to a hollow frame member 30 by fillet arc welding 32 is shown. FIG. 8 is a plan view seen from the direction. In the case of such a conventional connection structure, the position of the fillet arc welding 32 is determined by the neutral shaft 33 of the frame member.
8, the frame member 30 undergoes angular deformation (γ) due to welding. Therefore, as another embodiment, FIG. 9 shows a cross-sectional view in the direction perpendicular to the axis of the frame member 30 at the bracket connecting portion.

In FIG. 9, a bracket 50 is inserted into the outer wall of the hollow rectangular frame member 30, and fillet arcs 35 and 36 are applied as axial welding of the frame member 30. , Frame member 30 and bracket 31 are connected. Frame member 30
The positions of the fillet arc welding 35 on the upper surface side and the fillet arc 36 on the lower surface side are on the neutral shaft 33 in the left-right direction in the cross section of the frame member 30 in the direction perpendicular to the axis. Since it is arranged at a point symmetrical position with respect to 34, similarly to the above-described embodiment, no deformation force acts in the angular deformation direction, and angular deformation due to welding distortion can be prevented.

(Embodiment 7) FIG. 10 shows a modification of Embodiment 6, in which a bracket 37 is inserted into the outer wall portion of the frame member 30 having a hollow rectangular shape as described above, and the axial direction of the frame member 30 is changed. A joint structure is formed by the fillet arc welds 38 and 39 performed on the fins. In the present embodiment, the positions of the fillet arc weld 38 on the upper surface side and the fillet arc weld 39 on the lower surface side of the frame member 30 are point-symmetric with respect to the centroid 34 in the cross section of the frame member 30 in the direction perpendicular to the axis. Therefore, similarly to the above-described embodiment, the deformation caused by the fillet arc welding 38 on the upper surface side and the deformation caused by the fillet arc welding 39 on the lower surface side cancel each other, and the frame member In the end, almost no permanent deformation remains in 30 and the effect that welding distortion can be greatly reduced can be obtained.

(Embodiment 8) FIG. 11 shows still another embodiment. In FIG. 11, flanges of a cross member 41 and an outrigger 42 are fitted on upper and lower outer walls of the frame member 40 on both sides of the frame member 40 which is a hollow member. Fillet arc welding 43, 44, 45 and 46
And the three members are joined. In this embodiment, the fillet arc welding 43 on the upper side of the cross member 41 is used.
The lower fillet arc weld 44 of the outrigger 42 is disposed at a position facing the centroid 48 of the frame member 40, and the lower fillet arc weld 45 of the cross member 41 The fillet arc weld 46 on the upper side of the outrigger 42 is also disposed at a position facing the centroid 8 of the frame member 40, that is, at a point symmetrical position with respect to the centroid 48.

Therefore, also in the present embodiment, the fillet arc weld 43 on the upper side of the cross member 41 and the fillet arc weld 44 on the lower side of the outrigger 42 located at a point symmetric position with respect to the center of gravity 48. However, at the same time, the fillet arc welding 45 on the lower side of the cross member 41 and the
The fillet arc weld 46 on the upper side of the outrigger 42, which is located at a point symmetrical position with respect to 8, has a canceling action against each deformation. As a result, frame member 4
Finally, almost no permanent deformation remains at 0, so that the effect of significantly reducing welding distortion can be obtained as in the above-described embodiment.

As described above, the present invention has been described with some embodiments, but the present invention is not limited to these embodiments, and various modifications can be made within the scope of the present invention. For example, in the above-described embodiment, as an example to which the present invention can be applied, the side roof rail portion and the frame member portion of the frame body have been described. However, the application of the present invention is not limited to these parts, materials, and shapes. It can be applied to various member coupling structures.
Further, the control of the welding position according to the present invention does not need to be satisfied in all of the cross sections orthogonal to the axis of the first member.
It suffices that, within the range in which the member is tightly attached to the first member (the length of the first member in the axial direction), the cross section perpendicular to the axis relating to the welded portion is sufficient.

[0038]

As described above, according to the present invention, since the welding position between the hollow member and the member to be joined is appropriately controlled, the hollow member is used as a main structural member, and mainly the molten material is used. When manufacturing a frame structure body that is assembled by welding, it is possible to significantly suppress deformation of the body due to thermal distortion at the time of welding, and to provide a member coupling structure of a frame body suitable for securing good body dimensional accuracy. it can. That is, according to the member connecting structure of the frame body according to the first aspect, a hollow member that is lightweight, has high strength and high rigidity can be used as a main structural member, and is dimensionally resistant to deformation due to thermal distortion during welding. Since the desired dimensional accuracy of the vehicle body can be ensured without performing correction or the like, an excellent effect that a lightweight and high-strength frame-structured vehicle body can be easily obtained is brought about.

According to the second or third aspect, the same effect as that of the first aspect can be obtained. According to the fourth aspect, a hollow member having a lighter weight and a complicated sectional shape can be obtained. Can be used easily, and an extremely lightweight aluminum frame body having desired dimensional accuracy can be obtained. Further, according to the structure of claim 5, as the hollow material,
Molded products from steel pipes and rolled steel plates with low material costs can be used,
In addition, since it is possible to partially apply to a conventional monocoque body, a steel body having high strength and rigidity can be obtained at low cost. Furthermore, by adopting the configuration of claim 6, since the application of the parts to be welded is not limited by the presence or absence or shape of the parts to be welded, the degree of freedom in designing the member connecting portion of the frame body is drastically improved. And the practicality can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a member connecting structure of a frame body according to the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the member connecting structure of the frame body according to the present invention.

FIG. 3 is a characteristic diagram showing a relationship between a welding position and welding distortion.

FIG. 4 is a cross-sectional view showing another embodiment of the member connecting structure of the frame body according to the present invention.

FIG. 5 is a cross-sectional view showing another embodiment of the frame body member coupling structure of the present invention.

FIG. 6 is a cross-sectional view showing another embodiment of the member connecting structure of the frame body according to the present invention.

FIG. 7 is a perspective view showing another example of the conventional member connecting structure.

FIG. 8 is a plan view in the direction of arrow C in FIG. 7;

FIG. 9 is a sectional view showing still another embodiment of the member connection structure of the present invention.

FIG. 10 is a cross-sectional view showing another embodiment of the member connection structure of the present invention.

FIG. 11 is a sectional view showing another embodiment of the member connecting structure of the present invention.

FIG. 12 is a perspective view showing an example of a conventional automobile body structure.

FIG. 13 is a sectional view taken along line AA of FIG.

FIG. 14 is a side view in the direction of arrow B in FIG. 13;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Side roof rail 4 Pillar outer 5 Pillar inner 7, 8 Plug welding 9 Centroid 10 Neutral axis 11, 12 Fillet arc welding 20 Discarded bead 21 Steel side roof rail 30 Frame member 31 Bracket 41 Cross member 42 Outrigger

Claims (6)

[Claims] 1. A first member having a hollow and long length, and a second member which is narrowly attached to the first member and which is joined to the first member substantially perpendicularly to an axial direction of the first member by welding from outside. In the member coupling structure for a frame body provided, the welding position of the first member and the second member is arranged at a position substantially point-symmetric with respect to the centroid in a cross section orthogonal to the axial direction of the first member. A member connecting structure for a frame body, characterized in that: 2. The member connecting structure for a frame body according to claim 1, wherein at least one pair of the welding positions is disposed substantially on a neutral axis in the cross section orthogonal to the axis. 3. The member connecting structure for a frame body according to claim 1, wherein at least one pair of the welding positions is arranged at a position substantially axially symmetric with respect to a neutral axis in the cross section orthogonal to the axis. 4. The member connecting structure for a frame body according to claim 1, wherein the first member is made of an extruded member made of an aluminum alloy. 5. The molded product according to claim 1, wherein the first member is a bulge molded product or a roll molded product from a steel pipe or a steel plate, or a composite molded product obtained by combining them.
3. The member connecting structure for a frame body according to any one of the items 3 to 3. 6. A frame vehicle body according to claim 1, wherein a discard bead without member connection is arranged at at least one of a plurality of pairs of said welding positions. Member connection structure.