JP5392149B2 - Vehicle frame - Google Patents

Description

  The present invention relates to a vehicle frame used for vehicles such as trucks and large passenger cars.

  Conventionally, as a vehicle frame used as a vehicle body base portion of a vehicle such as a truck or a large passenger car (hereinafter collectively referred to as a truck or the like), a pair of left and right substantially extending in the longitudinal direction of the vehicle has been provided. Consists of side rails and a plurality of cross members connected to the pair of side rails and connecting the side rails to each other (sometimes called a ladder frame or a ladder frame because the planar configuration is a ladder) It has been known. Here, the side rail and the cross member are joined by welding, bolts, rivets or the like.

  FIG. 1 is a schematic perspective view of a vehicle frame 200 conventionally used for a vehicle body base portion of a vehicle such as a truck. As shown in FIG. 1, the vehicle frame 200 has a pair of substantially parallel side rails 205 and 206 extending in the longitudinal direction of the vehicle, and is joined so as to be orthogonal to the side rail 205 and the side rail 206. A plurality of cross members 210 are provided. The side rails 205 and 206 and the cross member 210 are joined by welding. Here, the plurality of cross members 210 are provided at equal intervals as shown in FIG.

  FIG. 2 is a cross-sectional view showing an example of the cross-sectional shape of the cross member 210. A cross-sectional shape of the cross member 210 may be a U-shape as shown in FIG. 2A or a substantially rectangular shape as shown in FIG. That is, the groove-shaped member 210 a and the square hollow member 210 b are mainly used as the cross member 210. FIG. 1 shows a case where a square hollow member 210b is used as a cross member.

  FIG. 1 and FIG. 2 show a conventional vehicle frame that has been used in the past. However, such a vehicle frame requires considerable rigidity to support a heavy vehicle body, The improvement of the rigidity is always required. Thus, for example, Patent Document 1 proposes a track chassis frame including side rails and cross members made of an aluminum alloy material.

  Further, for example, Patent Document 2 proposes a cross member excellent in torsional rigidity obtained by molding a single plate material, and discloses a vehicle frame constituted by using a plurality of the cross members and connecting to a side rail. Has been.

JP 2006-111228 A JP 2000-103358 A

  However, in the vehicle frame proposed and disclosed in Patent Document 1 and Patent Document 2, a plurality of groove-shaped members and square hollow members are used as cross members, for example, and side rails and respective cross members are welded, for example. Since the vehicle frame is configured by joining by means such as bolts, there are many joints between members (side rail and cross member), and there is a problem that the weight of the entire vehicle frame increases. . In addition, the joining process is complicated, and the manufacturing efficiency of the vehicle frame is reduced.

  Accordingly, in view of the above problems, an object of the present invention is to simplify a joining process such as welding by reducing the number of constituent members, and to obtain a vehicle frame that has sufficient torsional rigidity and is reduced in weight. It is to provide.

To achieve the above object, according to the present invention, a vehicle frame for supporting a vehicle body,
A pair of side rails arranged substantially parallel to extend along the longitudinal direction of the vehicle body;
One or two or more cross members each having both ends joined to the pair of side rails and made of a groove-shaped member or a square hollow member;
1 or 2 or more connecting members made of a hollow metal having side surfaces joined to the pair of side rails and having a closed cross section ;
The connecting member is provided with a vehicle frame having a shape formed on the inner side in a state where a plurality of internal spaces are divided .

The connecting member may be configured by fixing two substantially circular metal tubes. The connection portions where the two metal tubes are fixed to each other may be fixed by inserting the connection portion of one metal tube into the connection portion of the other metal tube.

According to the present invention, there is also provided a vehicle frame that supports the vehicle body, the pair of side rails that are arranged substantially in parallel along the longitudinal direction of the vehicle body, and both ends joined to the pair of side rails. One or two or more cross members made of a groove-shaped member or a square hollow member, and a side surface joined to the pair of side rails and made of a hollow metal having a closed cross section in a direction perpendicular to the longitudinal direction of the tube There is provided a vehicle frame including one or two or more connection members, wherein the connection members have a continuous or intermittent substantially elliptical loop shape. The connecting member may be configured by fixing ends of two substantially U-shaped metal tubes. The ends of the two metal tubes may be fixed by inserting the end of one metal tube into the end of the other metal tube. The two metal tubes may be integrally formed. The integral molding may be performed by hydroforming. Furthermore, the cross-sectional shape of the connecting member may be a flat shape.

  ADVANTAGE OF THE INVENTION According to this invention, while shortening joining processes, such as welding, by reducing the number of structural members, sufficient torsional rigidity is obtained and the vehicle frame reduced in weight is provided.

It is a schematic perspective view of the conventional vehicle frame 200. 4 is a cross-sectional view showing an example of a cross-sectional shape of a cross member 210. FIG. It is explanatory drawing of the process in which the flame | frame 1 for vehicles is manufactured. It is sectional drawing of the junction part of the connection member 10 and the side rail 20 which are XX cross sections of FIG.3 (d). It is explanatory drawing about torsion, in-plane shear, out-of-plane bending, and in-plane bending. 3 is a schematic plan view of a frame 50. FIG. FIG. 5 is a schematic plan view of a frame 60 when two connection members 10 and two connection members 10 ′ are provided. FIG. 4 is a schematic plan view of a frame 70 in which two connection members 10 and two connection members 10 ″ are provided and a cross member 30 is joined to each end portion. FIG. 6 is a schematic plan view of a frame 80 when the connecting member 10 takes an intermittent loop shape having an intermittent portion 75. FIG. 5 is a schematic plan view of a frame 90 configured to insert a cross member 30 into an intermittent portion 75. It is a schematic plan view of the frame 100 using the figure-shaped connection member 95. FIG. 10 is an explanatory diagram of a manufacturing process of the figure-shaped connecting member 95. It is explanatory drawing which shows an example of the joining method of metal tubes. It is explanatory drawing of the conventional flame | frame (comparative example). It is explanatory drawing of the flame | frame (Example 1) which is an example of this invention. It is explanatory drawing of the flame | frame (Example 2) which is an example of this invention. It is explanatory drawing of the flame | frame (Example 3) which is an example of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 3 is an explanatory view of a process of manufacturing the vehicle frame 1 (hereinafter referred to as the frame 1) according to the present embodiment. FIG. 3 (d) is finally completed as the frame 1. is there. Hereinafter, the manufacturing process of the frame 1 will be described with reference to FIG.

  As shown in FIG. 3A, two substantially U-shaped metal tubes 9, which are metal tubes having a closed cross section formed into a substantially U-shape, are prepared, and end portions of these metal tubes 9 are prepared. 9 ′ are butted together and joined by welding. The substantially U-shaped metal tube 9 is manufactured by integrally forming a hollow steel tube by, for example, hydroforming.

  By joining the end portions 9 ′ of the two substantially U-shaped metal tubes 9 in this way, a substantially elliptical loop-shaped connection member 10 is formed as shown in FIG. Then, as shown in FIG. 3C, side rails 20 and 21 are arranged on the outer sides of both side surfaces (upper and lower sides of the connecting member 10 in FIG. 3) parallel to the long diameter of the connecting member 10, respectively. 20, 21 and the connecting member 10 are joined by welding. The side rails 20 and 21 are manufactured by press molding, and the cross-sectional shape thereof is a U-shape. The side rails 20 and 21 are joined to the connection member 10 in a state where the opening side surfaces 20a and 21a are arranged inside the frame 1. Is called.

Further, at the same time when the connecting member 10 and the side rails 20 and 21 are joined, the side rails 20 and 21 and the plurality of cross members 30 are joined. The cross member 30 is a square hollow member, and is joined so that the side rails 20 and 21 and both end portions 30a and 30b of the plurality of cross members 30 are perpendicular to each other as shown in FIG. The joining positions of the cross members 30 on the side rails 20 and 21 can be arbitrarily set. In the present embodiment, two cross members 30 are arranged so as to form the longitudinal ends of the frame 1 (the side rails 20 and 21 are connected to each other). 1 is arranged in the vicinity of the connecting member 10. Although the cross member 30 is a square hollow member, the cross member 30 is not limited to this, and may be a groove member (groove steel) having a U-shaped cross section.

The number of cross members 30 used here can be arbitrarily determined according to the length of the side rails 20 and 21 and the rigidity and strength required for the frame 1 after completion. In the present embodiment, it is shown in FIG. Thus, three cross members 30 are used. In the present embodiment, only one connecting member 10 is joined between the side rails 20 and 21, but a plurality of connecting members 10 can naturally be used depending on the rigidity and strength required for the frame 1. .

  Through the steps shown in FIGS. 3A to 3C, the frame 1 having a structure in which the side rails 20, 21, the connecting member 10, and the cross member 30 are integrated as shown in FIG. 3D is manufactured. The By using the frame 1 manufactured in this way as a frame for supporting a vehicle body of a vehicle such as a truck, a highly rigid vehicle frame capable of supporting a heavy vehicle body can be obtained.

  FIG. 4 is a cross-sectional view of the joint between the connection member 10 and the side rail 20, which is an XX cross-section of FIG. As shown in FIG. 4, in the present embodiment, the connection member 10 (metal tube 9) is a hollow flat tube, and the side rail 20 is a groove member (channel steel) having a U-shaped cross section. The inner side (opening side surface) of the side rail 20 is fixed to the connecting member 10.

  Here, the rigidity of the frame 1 according to the present embodiment will be described with reference to FIG. FIG. 5 is an explanatory view of twist (a), in-plane shear (b), out-of-plane bending (c), and in-plane bending (d). As shown in FIG. 5 (a), the torsional rigidity is the frame 1 when a rotational moment (couple F) is applied to the side 1b opposite to the side 1a in a state where the side 1a of the frame 1 is fixed. The rigidity of is shown. As described above, in the frame 1 shown in FIG. 1, the connecting member 10 is made of a metal tube having a closed cross section. A hollow metal tube having a closed cross section has higher rigidity against twisting than steel materials such as steel bars. Therefore, the rigidity against twisting of the frame 1 as a whole is increased by the presence of the connecting member 10. Further, the connection member 10 and the side rail 20 (21) are fixed, whereby the rigidity against twisting is further increased.

Further, as shown in FIG. 5 (b), the rigidity against in-plane shear means that in a state where one side 1a of the frame 1 is fixed, a horizontal force F is applied to the side 1b facing the one side 1a in parallel with the side 1b. Rigidity when applied. In the frame 1 according to the present embodiment, since the connecting member 10 disposed inside the side rail 20 (21) plays a role of a brace, the rigidity of the frame 1 against in-plane shear is increased.

  Further, as shown in FIG. 5C, the rigidity against out-of-plane bending of the frame 1 is rigidity when a force F is applied to an arbitrary position of the frame 1 in a direction perpendicular to the surface of the frame 1. In the frame 1 according to the present embodiment, the side rail 20 (21) and the cross member 30 are joined so as to form a square shape, and the loop-shaped connecting member 10 and the side rail 20 (21) are fixed. As a result, the rigidity against out-of-plane bending becomes high.

  Further, as shown in FIG. 5D, the rigidity against in-plane bending is the horizontal force at an arbitrary position in the intermediate portion of the frame 1 with the sides 1a and 1b of the frame 1 being fixed. This is the rigidity when F is added. In the frame 1 according to the present embodiment, the connecting member 10 disposed inside the side rail 20 (21) works so as to efficiently transmit the force F acting on one side to the opposite side. The in-plane bending rigidity of the frame 1 is increased.

  As described above, the frame 1 according to this embodiment includes the side rails 20 and 21, the cross member 30, and the connection member 10. By using a metal tube having a closed cross section as the connecting member 10 or by integrating the connecting member 10 with the side rails 20 and 21 in a loop shape, the rigidity of the frame 1 is improved by the above-described twist, in-plane shear, Extremely high for out-of-plane bending and in-plane bending. In addition, since the connecting member 10 is configured by using a metal tube integrally formed by hydroforming, the number of members used for the frame 1 is reduced, and as a result, the frame 1 manufacturing process such as the joining process is simplified. . Furthermore, the weight of the frame 1 can be reduced by using a hollow metal tube.

  As mentioned above, although an example of embodiment of this invention was demonstrated, this invention is not limited to the form of illustration. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood.

  For example, in the configuration of the frame 1 in the above embodiment, the connection member 10 and the cross member 30 are not joined as shown in FIG. 3, but the present invention is not limited to this. It is also conceivable to join the rails 20 and 21 and the cross member 30 so as to be integrated.

  FIG. 6 is a schematic plan view of a frame 50 according to another example of the present invention in which the connecting member 10, the side rails 20, 21 and the cross member 30 are joined so as to be integrated. As shown in FIG. 6, in the frame 50, the side rails 20, 21 and the outer sides of both side surfaces parallel to the long diameter of the connection member 10 are joined by welding as in the above embodiment. The outer sides of both side surfaces parallel to the minor axis are joined to the cross member 30 by welding. That is, in the process of manufacturing the frame 50, the cross member 30 is disposed outside the both side surfaces parallel to the short diameter of the connection member 10, and when the connection member 10 and the side rails 20, 21 are joined, the connection member 10 and the cross The member 30 is also joined. In the frame 50 as well, the location and number of the cross members 30 can be appropriately changed as in the above embodiment, but at least two cross members 30 are parallel to the short diameter of the connecting member 10 on both side surfaces. It is necessary to be arranged outside of.

  According to the frame 50, although the joining process is slightly increased as compared with the frame 1 according to the above embodiment, the connecting member 10 is more robust in the plane A surrounded by the side rails 20, 21 and the two cross members 30. There is an advantage that the rigidity as the brace further increases.

  Moreover, in the said embodiment, although demonstrated as what uses the one connection member 10 as a component of the flame | frame 1, it can also be set as the structure which provides the several connection member 10 in one flame | frame. For example, FIG. 7 is a schematic plan view of the frame 60 when two connection members 10 and two connection members 10 ′ are provided. As shown in FIG. 7, in the frame 60, the two connection members 10, 10 ′ are joined so as to be sandwiched between the side rails 20, 21, and further, the longitudinal end of the frame 60 is formed. A cross member 30 is joined to the ends of the two side rails 20 and 21.

Here, FIG. 7 illustrates the case where the connecting members 10 and 10 ′ and the two cross members 30 are not joined, but the number of installed cross members 30 can be increased as appropriate. 10, 10 'and the cross member 30 may be joined. FIG. 7 shows the case where the number of connecting members 10 arranged in the frame is two, but this number can be changed as appropriate. Furthermore, the connecting member 10 and the connecting member 10 ′ can have different sizes (major diameters).

  Therefore, in FIG. 8, two connection members 10 ″ and two connection members 10 ″ having a longer diameter than the connection member 10 (having a longer diameter than the connection member 10) are provided. ) Shows a schematic plan view of the frame 70 to which the cross member 30 is joined. The major axis of the connecting member 10 ″ is preferably determined as appropriate according to the required size of the frame 70.

  According to the frame 60 and the frame 70 described above, since the two connection members 10, 10 ′ or the connection members 10, 10 ″ are used as compared with the frame 1 according to the above embodiment, two connection members are provided. Both function as a brace of the frames 60 and 70, thereby providing an advantage that the rigidity is increased.

  Further, in the frame 1 according to the above embodiment, the connecting member 10 has a substantially elliptical loop shape. However, in the present invention, the connecting member 10 has an intermittent portion 75 as shown in FIG. It is good also as taking an intermittent loop shape. In the frame 80 having the intermittent loop-shaped connection member 10 shown in FIG. 9, the intermittent portion 75 of the connection member 10 is provided in the opposing linear shape portion of the connection member 10, but is not limited thereto. Instead, it may be provided in the semicircular portion. Moreover, although the case where the intermittent part 75 is provided in two places was shown in FIG. 9, it does not necessarily need to be two places. However, when providing the intermittent part 75, the intermittent part 75 of the connection member 10 needs to be joined to either of the side frames 20 and 21, and the mutual members (the connection member 10 and the side frames 20 and 21) are connected to each other. In between, force needs to be transmitted.

  By providing the connection member 10 with the intermittent portion 75, the torsional rigidity of the frame 80 can be controlled to achieve necessary and sufficient performance, and the weight of the frame 80 can be reduced.

  Moreover, when the intermittent part 75 is provided in the linear shape part which the connection member 10 opposes, inserting the cross member 30 in the intermittent part 75 is also considered. FIG. 10 is a schematic plan view of a frame 90 in which the connection member 10 is provided with an interrupting portion 75 and the cross member 30 is inserted into the interrupting portion 75. According to this frame 90, since the cross member 30 is inserted into the intermittent portion 75 and the side rails 20, 21, the connecting member 10, and the cross member 30 are integrated, the rigidity of the entire frame 90 is increased.

  Furthermore, in the present invention, it is conceivable to use a metal tube having a shape formed inside, for example, an 8-shaped metal tube, in a state where a plurality of internal spaces are divided as the connecting member. FIG. 11 is a schematic plan view of a frame 100 using an 8-shaped connecting member 95 manufactured using an 8-shaped metal tube. As shown in FIG. 12, the figure-shaped connecting member 95 is obtained by connecting two substantially circular metal pipes 105 at two connecting portions 105 '. The metal tube 105 is formed by joining a hollow linear metal tube having a closed cross section in a loop shape and joining the outer peripheral surfaces of the end portions of the metal tube in a state where both end surfaces 106 are aligned. Is formed. In this formation process, an internal space 107 is formed inside the substantially circular metal tube 105. Here, the substantially circular metal tube 105 can be manufactured by being integrally formed by, for example, hydroforming. However, the method of forming the substantially circular metal pipe 105 is not limited to this, and for example, the metal pipe 105 may be formed by joining both ends of a U-shaped steel pipe.

  In the above-described embodiment of the present invention and its modifications, the connection member 10, the side rails 20 and 21, and the cross are formed when the substantially U-shaped metal pipes 9 constituting the connection member 10 are joined and fixed together. Although the joining between the members of the member 30 has been described on the assumption that welding is used, the present invention is not limited to this. For example, as shown in FIG. 13, the joining of the metal tubes 9 is performed by inserting an end portion 9 ′ that is a connecting portion of one metal tube 9 into an end portion 9 ′ that is a connecting portion of the other metal tube 9. The connection member 10 may be configured by joining two metal tubes. With this configuration, it is possible to reduce the number of welding steps during frame production and produce the frame 1 more efficiently. In addition, after the end portion 9 ′ of one metal tube 9 is inserted into the end portion 9 ′ of the other metal tube 9, the end portion 9 ′ is fixed using a screw or the like, so that the joining is more reliable.

  The torsional rigidity of a conventionally known ladder frame and a frame provided with a connection member having a substantially elliptical loop shape according to the present invention were measured and compared. FIG. 14 shows a conventionally known ladder frame (comparative example). As shown in FIG. 14, the ladder frame according to this comparative example is a ladder frame composed of a pair of left and right side rails and eight cross members provided to connect the side rails to each other. It was.

  On the other hand, FIG. 15 shows a vehicle frame (Example 1) according to the present invention. As shown in FIG. 15, the vehicle frame according to the first embodiment includes a pair of left and right side rails, four cross members provided so as to connect the side rails, and a substantially elliptical shape. A vehicle frame constituted by joining two connecting members each having a loop shape on both side surfaces to a pair of side rails was used. In other words, a vehicle frame configured by increasing the number of connection members to two in the (vehicle) frame described with reference to FIG. 3 in the above embodiment is used. The plate thickness of the side rail and cross member used in this example was 7.0 mm, and the plate thickness of the connecting member was 1.8 mm. Further, the total weight of the entire frame in the ladder frame (comparative example) and the vehicle frame (Example 1) was equal.

  Here, in the ladder frame (comparative example) shown in FIG. 14 and the vehicle frame (example 1) shown in FIG. 15, a force is applied as shown by an arrow P in FIG. 14, and the torsional rigidity of each frame is measured. The comparison was made. As a result, it was found that the value of the torsional rigidity of the vehicle frame (Example 1) shown in FIG. 15 was 1.7 times that of the value of the torsional rigidity of the ladder frame (Comparative Example) shown in FIG. Since both frames have the same total weight, the two types of frames manufactured using almost the same amount of material have a large difference in torsional rigidity as described above. It was also found that the vehicle frame has superior torsional rigidity compared to the conventional frame.

  FIG. 16 is a modification (Example 2) of the vehicle frame according to the present invention. The vehicle frame according to the second embodiment includes a pair of left and right side rails, six cross members provided so as to connect the side rails to each other, and one connection member having a substantially elliptical loop shape. A vehicle frame constituted by joining both side surfaces to a pair of side rails was used. That is, the (vehicle) frame described with reference to FIG. 3 in the above embodiment was used. The plate thickness of the side rail and cross member used in this example was 7.0 mm, and the plate thickness of the connecting member was 1.8 mm. Further, the total weight of the entire frame in the ladder frame (comparative example) and the vehicle frame (Example 2) was equal.

  The torsional rigidity of Example 2 shown in FIG. 16 and the comparative example shown in FIG. 14 were compared by the same method as in Example 1. As a result, the torsional rigidity of Example 2 was compared with that of Comparative Example. The value of was found to be 1.25 times.

  FIG. 17 shows a modification (Example 3) of the vehicle frame according to the present invention. The vehicle frame according to the third embodiment is substantially the same as the above-described embodiment. However, as shown in FIG. 17, a substantially elliptical loop-shaped connection member is divided at the central dividing portion to obtain two U-shaped members. There is a feature in that.

  The torsional rigidity of Example 3 shown in FIG. 17 and the comparative example shown in FIG. 14 were compared by the same method as in Example 1. As a result, the torsional rigidity of Example 3 was compared with that of Comparative Example. The value of was found to be 1.1 times.

  As described above, the torsional rigidity of the three examples was compared with that of the comparative example, which is a conventional technique. In four types of frames manufactured using substantially the same amount of material, a difference of 1.1 times to 1.7 times in the torsional rigidity was produced as described above. Therefore, the vehicle provided with the connection member according to the present invention It was found that the frame for use has superior torsional rigidity compared to the conventional frame. In the three embodiments, in order to fairly compare the torsional rigidity, which is an important structural performance of the frame, the cross sections of the side rail and the cross member are U-shaped (groove shape), and in the material length direction. Is uniform and simplified. In addition, the substantially elliptical connection member is simplified by assuming that the cross section is rectangular and the cross section in the material length direction (the length direction of the metal tube) is uniform. However, in reality, due to the convenience of structure and assembly / workability, not only the U-shape and rectangle presented in the present invention, but also various cross-sectional shapes configured by press molding, roll molding, hydroform molding, etc. In general, the cross-sectional shape changes appropriately in the material length direction. The contents shown in the invention of the present application can be applied to a vehicle frame that is composed of side rails, cross members, and connecting members that have complicated sectional shapes that are generally used and are not uniform in the material length direction.

  The present invention can be applied to a vehicle frame used in vehicles such as trucks and large passenger cars.

DESCRIPTION OF SYMBOLS 1, 50, 60, 70, 80, 90, 100 ... (Vehicle) Frame 9 ... Metal pipe of substantially U shape 9 '... End part 10, 10', 10 '' ... Connection member 20, 21 ... Side Rail 30 ... Cross member 75 ... Intermittent part 95 ... Eight-shaped connecting member 105 ... Substantially circular metal pipe 105 '... Connecting part 106 ... End face 107 ... Internal space

Claims (9)

A vehicle frame for supporting a vehicle body,
A pair of side rails arranged substantially parallel to extend along the longitudinal direction of the vehicle body;
One or two or more cross members each having both ends joined to the pair of side rails and made of a groove-shaped member or a square hollow member;
1 or 2 or more connecting members made of a hollow metal having side surfaces joined to the pair of side rails and having a closed cross section ;
The connection member is a vehicle frame having a shape formed inside in a state where a plurality of internal spaces are divided . The vehicle frame according to claim 1, wherein the connection member is configured by fixing two substantially circular metal pipes. The vehicle frame according to claim 2, wherein the connection portions to which the two metal tubes are fixed to each other are fixed by inserting a connection portion of one metal tube into a connection portion of the other metal tube. A vehicle frame for supporting a vehicle body,
A pair of side rails arranged substantially parallel to extend along the longitudinal direction of the vehicle body;
One or two or more cross members each having both ends joined to the pair of side rails and made of a groove-shaped member or a square hollow member;
1 or 2 or more connecting members made of a hollow metal having side surfaces joined to the pair of side rails and having a closed cross section in a direction perpendicular to the longitudinal direction of the pipe,
The vehicle frame is a continuous or intermittent substantially elliptical loop shape. The vehicle frame according to claim 4, wherein the connection member is configured by fixing ends of two substantially U-shaped metal tubes. 6. The vehicle frame according to claim 5, wherein the ends of the two metal tubes are fixed by inserting the end of one metal tube into the end of the other metal tube. The vehicle frame according to any one of claims 2, 3, 5, and 6, wherein the two metal pipes are integrally formed. The vehicle frame according to claim 7, wherein the integral molding is performed by hydroforming. The vehicle frame according to claim 1, wherein a cross-sectional shape of the connection member is a flat shape.

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