JP2007268594A - Frame made of aluminum alloy and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a frame made of an aluminum alloy and a method for manufacturing the same wherein a closed cross-sectional structure having flat surfaces is obtained after joining by welding and a high accuracy frame complying with a design specification is easily obtained. <P>SOLUTION: Frame members which have a U-shaped cross section in the width direction are obtained by press-forming an aluminum ally sheet. These frame members 10, 11 have the middle parts 10a, 11a in the width direction and both side parts 10b, 11b which are bent so as to orthogonally cross to these middle parts, wherein for both the side parts 10b, 11b, the intervals between open end parts are equal to or smaller than the intervals between end parts on the sides of the middle parts, and the middle parts are outward curved. The frame member 11 is locked with a locking member 14, the frame members 10, 11 are pressed with welding tools 12a, 12b and pressing members 13a, 13b and, when the side parts are joined each other by welding, the frame having the flat surfaces is obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an aluminum alloy frame used for a track frame and the like, and a method for manufacturing the same, and in particular, in a track frame structure using a medium thickness aluminum alloy plate having a plate thickness of 4 mm or more, positioning accuracy at the time of manufacture is improved. The present invention relates to an improved aluminum alloy frame member and a method of manufacturing the same.

  A member having a U-shaped cross section is used for the frame of the track. However, due to the recent demand for weight reduction of the car body, the use of aluminum alloy plates has been promoted instead of steel plates, and from the viewpoint of rigidity and collision safety, it is made of a closed cross-section aluminum alloy with a “R” -shaped cross section. The use of frames is being considered. For example, Patent Document 1 is an example in which an extruded shape is used for a frame, but the extruded shape has a substantially identical cross-sectional shape in the longitudinal direction due to its manufacturing method, and it is difficult to manufacture a frame whose cross section changes. is there.

  For this reason, this closed-section aluminum alloy frame having a cross-sectional “B” shape is manufactured by first press-molding a frame member having a cross-section “U” shape, and both ends in the width direction bent in the same direction, It is manufactured by joining the other cross-sectionally “U” -shaped frame members to both ends in the width direction, which are bent in the same direction, by welding.

  That is, first, as shown in FIG. 6, an aluminum alloy plate is formed by press molding so that the cross section has a “U” shape, thereby obtaining the frame member 1. At this time, the aluminum alloy frame member 1 is formed with a center portion 1a in the width direction and both side portions 1b bent by press molding so as to be bent perpendicularly to the center portion 1a. . And as shown in FIG. 7, the width direction edge part (open end part) of the frame member 1 made from aluminum alloy is weld-joined. That is, a hole 5 is formed in the center of the central portion 1a of the aluminum alloy frame member 1 in a cross-section "U" shape, and a pair of welding jigs 2a and 2b in which the hole 6 is formed. The aluminum alloy frame member 1 is sandwiched between the holes 5 and 6 so that the pins 4a and 4b having the heads are sandwiched between the head and the jigs 2a and 2b. Thus, the aluminum alloy frame member 1 is fixed to the welding jigs 2a and 2b by the pins 4a and 4b by being inserted into the holes 5 and 6, respectively. Thereby, the aluminum alloy frame member 1 is restrained in the horizontal direction by the welding jigs 2a and 2b. Then, the pair of side portions 1b of the aluminum alloy frame member 1 are pressed by the pressing jigs 3a and 3b from above and below, and the aluminum alloy frame member 1 is restrained in the vertical direction by the pressing jigs 3a and 3b. To do. In this state, the open ends of the side portions 1b of the aluminum alloy frame member 1 are joined together by welding.

Japanese Patent Laid-Open No. 10-314869

  However, the above prior art has the following problems. As shown in FIG. 6, first, an aluminum alloy plate is formed by press forming so that the cross section has a “U” shape. At this time, in the press forming, the central portion 1 a and the side portion 1 b have 90 parts. Although it is processed so as to form an angle of °, the side portion 1b is actually formed in an open state with respect to the central portion 1a by a phenomenon called spring back.

  Therefore, as shown in FIG. 7, when the aluminum alloy frame member 1 is constrained between the welding jigs 2a and 2b and between the pressing jigs 3a and 3b, the central portion 1a of the aluminum alloy frame member 1 has an arcuate shape. Bend. For this reason, when the side portions 1b of the pair of aluminum alloy frame members 1 are welded to each other, the obtained closed cross-section frame has a central portion 1a that should be flat in a bow shape. Since the shape according to the design specification is not obtained, the rigidity and strength of the frame are lowered, and the reliability in actual use is impaired.

  Furthermore, as shown in FIG. 8, when the aluminum alloy plate to be used is made of a material having a large spring back, the frame member 1 warps so that the central portion 1a thereof is convex inward. Then, as shown in FIG. 9, the central portion 1a is pulled outward by the pins 4a and 4b, and the central portion 1a is brought into contact with the welding jigs 2a and 2b as shown by the solid line in FIG. Even if it tries to make it, it will become very difficult to correct to flat form. For this reason, when the spring back is made of a large material, as shown by a broken line in FIG. 9, the central portion 1a remains deformed so as to protrude inward, and a flat frame having a closed cross-sectional structure cannot be obtained.

  The present invention has been made in view of such problems, and after welding, an aluminum alloy is obtained in which a closed cross-sectional structure having a flat surface is obtained and a high-accuracy frame according to design specifications can be easily obtained. An object of the present invention is to provide a manufacturing frame and a manufacturing method thereof.

  An aluminum alloy frame according to the present invention includes a pair of aluminum alloy frame members formed so as to have a U-shaped cross section by press molding, and the widthwise open ends of the pair of frame members. And the frame member has a center portion in the width direction and both side portions bent by press molding so as to be orthogonal to the center portion. Is characterized in that the distance between the open ends is equal to or smaller than the distance between the ends on the center side, and the center is curved outward. .

  A method of manufacturing an aluminum alloy frame according to the present invention is a frame member in which an aluminum alloy plate is press-molded and a cross section in the width direction is U-shaped, and a center portion in the width direction and the center portion. Both side portions bent by press molding so as to be orthogonal to each other, and the both side portions have an interval between the open ends equal to or smaller than an interval between the end portions on the center portion side, and the center. A step of obtaining a frame member whose portion is curved outward, a frame in which a pair of frame members are overlapped with each other between a pair of welding jigs, and the open ends are overlapped on the inside A step of disposing a locking member that locks the pair of open end edges of the member, and pressing the pair of side portions of the frame member stacked on the outside in a direction approaching each other by a pressing jig, By welding jig and pressing jig And having the step of constraining the frame member of said pair, and bonding by welding the sides together superimposed a frame member of said pair.

  According to the present invention, a frame member is formed by press-molding an aluminum alloy plate, and the pair of side portions of the frame member has an interval between the open ends equal to or smaller than the interval between the end portions on the center side. The frame member is curved outward at the time of press molding by forming, constraining the center part of the frame member with a pair of welding jigs, and pressing the outer surfaces of each pair of side parts with a pressing jig. The center portion is flat and the pair of side portions of each frame member are parallel to each other. Therefore, if the open ends of the pair of frame members are joined together by welding in this constrained state, the frame can be obtained in which the cross section is rectangular and all the surfaces are flat. Therefore, according to the present invention, it is possible to obtain a frame member having a highly accurate shape according to design specifications.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a frame member used for manufacturing an aluminum alloy frame according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the manufacturing method. In this embodiment, first, an aluminum alloy plate is press-molded to form the frame members 10 and 11 whose cross section basically forms a “U” shape. Each frame member 10, 11 has a center portion 10a, 11a and both side portions 10b, 11b in the width direction, and the both side portions 10b, 11b are substantially orthogonal to the center portions 10a, 11a. It is bent with respect to the central portions 10a and 11a. The central portions 10a and 11a are curved or bent outward. The angles formed by the side portions 10b and 11b with respect to the central portions 10a and 11a are right angles or angles near the central portions 10a and 11a. Therefore, the central portions 10a and 11a are curved or bent outward. As for the frame members 10 and 11, the space | interval between the open ends of the side parts 10b and 11b is equal to or smaller than the space | interval between the edge parts by the side of a center part. In this way, at least the central portions 10a and 11a are curved or bent outward, and the interval between the open ends of the side portions 10b and 11b is equal to or smaller than the interval between the end portions on the central portion side. In consideration of the spread due to the spring back, the pressing conditions of the aluminum alloy plate in the press forming are set. Alternatively, the press condition may be set to cause a spring go so that the distance between the open ends of the side portions 10b and 11b of the frame member after molding is smaller than the interval between the end portions on the center side. .

  As shown in FIG. 2, the aluminum alloy frame members 10, 11 press-formed to have such a shape are partially overlapped with each other, and a pair of welding jigs 12 a, 12b. In this embodiment, since the interval between the end portions of the side portion 10b is larger than the interval between the end portions of the side portion 11b, the side portion 10b overlaps the outer surface of the side portion 11b, and the side portion 10b is on the side. It arrange | positions so that the part 11b may be pinched | interposed. Then, a locking member 14 having a “U” -shaped cross section is placed on the inner surface of the larger frame member 10, and both end edges of the locking member 14 are arranged at both ends of the open end of the smaller frame member 11. The frame member 11 is constrained by the frame member 10 and the locking member 14 while being matched to the edge. In this state, as shown by a broken line in FIG. 2, the central portions 10a and 11a bulge outward, and the side portions 10b and 11b have shapes that overlap.

  Next, the pressing jigs 13 a and 13 b are brought into contact with the outer surface of the side portion 10 b of the frame member 10, and the pressing jigs 13 a and 13 b are bent portions between the center portion 10 a and the side portion 10 b of the frame member 10. The welding jigs 12a and 12b are moved closer to each other, and the center portions 10a and 11a of the frame members 10 and 11 are pressed. Thereby, the frame members 10 and 11 are deformed so that the central portions 10a and 11a thereof become flat in accordance with the opposing surfaces of the welding jigs 12a and 12b. At this time, the open end edge of the smaller frame member 11 is locked by the locking member 14, and this locking member 14 resists the frame member 11 against the pressing of the welding jigs 12a and 12b. The locking member 14 exerts a drag force in the vicinity of the bent portion of the larger frame member 10. In this state, the pressing force is applied to the frame members 10 and 11 in the direction in which the welding jigs 12a and 12b approach each other, so that the center portions 10a and 11a of the frame members 10 and 11 are welded jigs 12a. , 12b, and deforms so as to be flat. Thereby, each pair of side parts 10b and 11b of each frame member 10 and 11 becomes mutually parallel.

  In this state, the side part 10b and the side part 11b are joined by welding. Thus, a frame having a closed cross-sectional structure in which the side portions 10b and 11b are parallel to each other and the central portions 10a and 11a are flat is obtained. Therefore, this frame has a rectangular cross-sectional shape, its four surfaces are flat, and has a highly accurate cross-sectional shape that matches the design specifications. FIG. 3 shows the cross-sectional structure of the frame after welding. The frames joined by the welded portion 15 are flat on each of the four surfaces, and are highly reliable in terms of strength and rigidity.

  As shown in FIGS. 4 and 5, the frame of the present invention has a rectangular cross-sectional shape, but the shape in the longitudinal direction can be arbitrarily formed.

  In the present invention, as shown in FIG. 1, the cross-sectional shape of the frame members 10 and 11 after press molding simply enters the inside of the open ends of the side portions 10b and 11b, and the center portions 10a and 11a outward. By simply setting so as to swell, it is possible to obtain a frame having a closed cross-sectional shape with four sides that are extremely simple. For this reason, the frame of the present invention can obtain rigidity and strength as designed, and has high reliability when incorporated in a track or the like.

  In the present invention, pins 4a and 4b as shown in FIGS. Therefore, it is not necessary to provide the hole 5 in the frame member, and it is not necessary to provide the hole 6 in the welding jig. For this reason, a pin having a complicated structure and having a problem with the durability of the head, such as the pins 4a and 4b, can be omitted. It is possible to prevent the deterioration of strength. The locking member 14 does not need to be provided in the entire structure of the frame, and may be installed only at a portion necessary for menopause of the frame member. The shape of the locking member 14 is not limited to the case where the cross section is a “U” shape, and the frame members 10, 11 such as a member having a L-shaped cross section structure, a plate material, a block, a reinforcement material, etc. As long as it can hold | maintain between 12b, various things can be used.

It is sectional drawing which shows the frame member of embodiment of this invention. It is sectional drawing which shows the manufacturing method of the flame | frame of embodiment of this invention. It is sectional drawing which shows the cross-sectional shape of the flame | frame of embodiment of this invention. It is a figure which shows the flame | frame of this invention. It is a figure which similarly shows the flame | frame of this invention. It is sectional drawing which shows the conventional frame member. It is a figure which shows the manufacturing method of the conventional flame | frame. It is sectional drawing which shows the frame member in the case of the material with the conventional large spring back. It is a figure which shows the manufacturing method of the flame | frame using it.

Explanation of symbols

1, 10, 11; frame members 1a, 10a, 11a: central portions 1b, 10b, 11b: side portions 2a, 2b, 12a, 12b: welding jigs 3a, 3b, 13a, 13b: pressing jig 14: engagement Stop member

Claims (2)

A pair of aluminum alloy frame members formed so as to have a U-shaped cross section by press molding, and a welded portion in which the open ends in the width direction of the pair of frame members are welded together The frame member has a center part in the width direction and both side parts bent by press molding so as to be orthogonal to the center part, and the both side parts have an interval between the open ends described above. An aluminum alloy frame characterized by being processed so that the distance between the ends on the central portion side is equal to or smaller than the distance between the ends and the central portion is curved outward. A frame member that is formed by pressing an aluminum alloy plate and has a U-shaped cross section in the width direction, and a center portion in the width direction and both side portions bent by press forming so as to be orthogonal to the center portion And the both side portions obtain a frame member in which the distance between the open end portions is equal to or smaller than the interval between the end portions on the central portion side, and the central portion is curved outward, A pair of frame members are disposed between a pair of welding jigs with their open ends overlapped, and the pair of open ends of the frame member with the open ends overlapped inside is locked. The step of disposing the locking member and the pair of side portions of the frame member stacked on the outside are pressed in a direction approaching each other by a pressing jig, and the pair of frames are pressed by the welding jig and the pressing jig. A step of restraining the member, and the pair of Method for producing Aruminimu alloy frame, characterized in that it comprises a step of joining by welding the sides together superimposed the frame member.

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