Vehicle body rear part structure

Abstract

In a vehicle body rear part structure comprising a side sill 20 and a rear frame 40, a tip part of a frame floor part 49 is placed on an inner overhang part 27, and an inner roof part 25 is covered by

Description

Title: VEHICLE BODY REAR PORTION STRUCTURE TECHNICAL FIELD

[0001] The present invention relates to a vehicle body rear portion structure including a side sill and a rear frame. BACKGROUND ART

[0002] Various vehicle body rear portion structures including a side sill and a rear frame have been proposed (for example, see Patent Document 1 (FIG. 3)).

[0003] Patent Document 1 will be described with reference to the following drawings. FIG. 12 is a cross-sectional view of main parts of a conventional vehicle body rear portion structure. In the vehicle body rear portion structure, a rear frame 104 is fitted to a side sill 101, which is composed of a side sill outer 102 and a side sill inner 103, from the inside of a vehicle body, and both members are joined at joining portions 105. The rear frame 104 is a cast article that is thicker than the side sill 101.

[0004] The process of joining the side sill 101 and the rear frame 104 will be examined. When the side sill 101 is stationary, the rear frame 104 is moved horizontally. In addition, the center of the rear frame 104 in a height direction is aligned with the center of the side sill 101 in the height direction.

[0005] That is, in the conventional vehicle body rear portion structure, it is necessary to raise and lower the rear frame 104 while moving the rear frame 104 horizontally relative to the side sill 101. It is not easy to fitting the rear frame 104 while moving the rear frame 104 horizontally. Therefore, the manufacturing costs of the vehicle body rear portion structure increase.

[0006] However, there is a demand to provide vehicles at low cost, and as part of the effort, reducing the manufacturing costs of the vehicle body rear portion structure is required. CITATION LIST PATENT DOCUMENT

[0007] Patent Document 1: Japanese Patent No. 7074039 DISCLOSURE OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0008] An object of the invention is to provide a vehicle body rear portion structure that can reduce manufacturing costs. MEANS FOR SOLVING PROBLEM

[0009] The invention according to a first aspect is a vehicle body rear portion structure including a side sill; and a rear frame extending from the side sill toward a rear of a vehicle body. The side sill includes a side sill outer disposed on an outside of the vehicle body, and a side sill inner disposed closer to an inside of the vehicle body than the side sill outer. The side sill inner includes an inner wall portion extending vertically, an inner roof portion extending from an upper end of the inner wall portion toward the outside of the vehicle body, an inner flange portion extending upward from a tip of the inner roof portion, and an inner protruding portion protruding laterally toward the inside of the vehicle body from midway in a height direction of the inner wall portion. A front portion of the rear frame includes a frame wall portion extending vertically, a frame roof portion extending from an upper end of the frame wall portion toward the outside of the vehicle body, and a frame floor portion extending from a lower end of the frame wall portion toward the outside of the vehicle body such that the front portion has a U-shaped cross-section. A tip portion of the frame floor portion is placed on the inner protruding portion, and the frame roof portion covers the inner roof portion from above. In this form, the front portion of the rear frame is fixed to the side sill. EFFECT OF THE INVENTION

[0010] In the invention according to the first aspect, the tip portion of the frame floor portion is placed on the inner protruding portion, and the frame roof portion covers the inner roof portion from above. That is, the rear frame can be fixed to the side sill simply by lowering the rear frame from above onto the side sill that is stationary. Horizontal movement of the rear frame is not essential, but the rear frame only needs to be moved from top to bottom. It is easy to move the rear frame downward. Therefore, the manufacturing costs of the vehicle body rear portion structure can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0011] FIG. 1 is a side view of a vehicle body rear portion structure according to the invention; FIG. 2 is a view taken on arrow 2 in FIG. 1; FIG. 3(a) is a side view of a rear frame, FIG. 3(b) is a cross-sectional view taken along line b-b in FIG. 3(a), and FIG. 3(c) is a cross-sectional view taken along line c-c in FIG. 3(a); FIG. 4(a) is an enlarged view of portion 4a in FIG. 3(b), FIG. 4(b) is an enlarged view of portion b in FIG. 4(a), and FIG. 4(c) is a view illustrating a modification example of a center of the rear frame; FIG. 5(a) is an exploded view of a side sill, and FIG. 5(b) is a cross-sectional view of the side sill; FIG. 6(a) is a view describing a procedure for joining the rear frame to the side sill, FIG. 6(b) is a cross-sectional view taken along line 6b-6b in FIG. 2, FIG. 6(c) is an enlarged view of portion c in FIG. 6(b), and FIG. 6(d) is an enlarged view of portion d in FIG. 6(b); FIG. 7(a) is an exploded view of a front end connecting member, and FIG. 7(b) is a cross-sectional view of the front end connecting member; FIG. 8(a) is a view describing a procedure for joining the rear frame to the side sill and a procedure for joining the front end connecting member to the rear frame, FIG. 8(b) is a cross-sectional view taken along line 8b-8b in FIG. 2, FIG. 8(c) is an enlarged view of portion c in FIG. 8(b), FIG. 8(d) is an enlarged view of portion d in FIG. 8(b), and FIG. 8(e) is an enlarged view of portion e in FIG. 8(b); FIG. 9(a) and FIG. 9(b) are views describing the height position of an inner protruding portion; FIG. 10(a) and FIG. 10(b) are views describing a modification example of the inner protruding portion; FIG. 11(a) and FIG. 11(b) are views describing the function of the center of the rear frame; and FIG. 12 is a cross-sectional view of main parts of a conventional vehicle body rear portion structure. BEST MODE FOR CARRYING OUT THE INVENTION

[0012] An embodiment of the invention will be described below with reference to the accompanying drawings. Incidentally, in the drawings, the front, rear, top, bottom, inside, and outside of a vehicle body are defined with reference to a driver aboard a vehicle. [Embodiment]

[0013] [Vehicle body rear portion structure] As illustrated in FIG. 1, a vehicle body rear portion structure 10 includes a side sill 20; a rear frame 40 extending rearward from the side sill 20; and a rear wheel housing 12 disposed outside the rear frame 40.

[0014] In addition, as illustrated in FIG. 2, the vehicle body rear portion structure 10 includes a floor cross member 14 disposed in front of the rear frame 40 and extending from the side sill 20 toward the inside of the vehicle body, and a front end connecting member 60 that connects a front end of the rear frame 40 and the floor cross member 14. Incidentally, a floor panel is not illustrated in FIG. 2.

[0015] [Rear frame] As illustrated in FIG. 3(a), the rear frame 40 is an elongated member extending forward and rearward. Preferably, the rear frame 40 is a die-cast article made of an aluminum alloy. The aluminum alloy is a lightweight alloy, and the weight of the rear frame 40 can be reduced. However, in order to further reduce the weight, material removal is performed using a first groove 41 and a second groove 42.

[0016] By providing the first groove 41 and the second groove 42, the weight can be further reduced; however, the strength is reduced. Therefore, preferably, the first groove 41 is provided with a plurality of (two in this example) I-shaped ribs 43 extending vertically, and the second groove 42 is provided with a plurality of (six in this example) the I-shaped ribs 43 extending vertically. A portion above the first groove 41 and the second groove 42 forms a frame flange portion 44. In addition, an inner rib-shaped flange 45 is illustrated by dashed lines between the first groove 41 and the second groove 42 and above the second groove 42.

[0017] Since the rear frame 40 illustrated in FIG. 3(a) is also offset in a front-to-back direction of the drawing, the cross-section differs depending on the portion in a front-to-rear direction of the vehicle body. Therefore, the cross-section at a front portion will be described with reference to FIG. 3(b), and the cross-section at a center will be described with reference to FIG. 3(c).

[0018] [Cross-section of front portion of rear frame] As illustrated in FIG. 3(b), the front portion of the rear frame 40 includes a frame wall portion 47 extending vertically; a frame roof portion 48 extending from an upper end of the frame wall portion 47 toward the outside of the vehicle body; the frame flange portion 44 extending upward from a tip of the frame roof portion 48; and a frame floor portion 49 extending from a lower end of the frame wall portion 47 toward the outside of the vehicle body; and has a U-shaped cross-section, the opening of which gradually widens outward. The first groove 41 is reinforced by the I-shaped ribs (reference numeral 43 in FIG. 3(a)) that crosses the U-shaped cross-section.

[0019] Preferably, the rear frame 40 further includes the inner rib-shaped flange 45 protruding laterally from the upper end of the frame wall portion 47 toward the inside of the vehicle body. Details of the inner rib-shaped flange 45 will be described later with reference to FIG. 4(a).

[0020] [Cross-section of center of rear frame] As illustrated in FIG. 3(c), the center of the rear frame 40 includes the frame wall portion 47 extending vertically; the frame roof portion 48 extending from the upper end of the frame wall portion 47 toward the outside of the vehicle body; the frame flange portion 44 extending upward from the tip of the frame roof portion 48; and the frame floor portion 49 extending from the lower end of the frame wall portion 47 toward the outside of the vehicle body. Preferably, the rear frame 40 further includes the inner rib-shaped flange 45 protruding laterally from the lower end of the frame wall portion 47 toward the inside of the vehicle body. The second groove 42 is reinforced by the I-shaped ribs 43 that crosses the U-shaped cross-section.

[0021] [Inner rib-shaped flange] As illustrated in FIG. 4(a), a thickness tl of a base of the inner rib-shaped flange 45 is set to be approximately equal to a thickness t2 of the frame wall portion 47. Further, the inner rib-shaped flange 45 is a pointed tapered rib, the thickness of which decreases toward the tip due to the casting draft angle. The tip of the pointed tapered rib may have a protruding shape; however, preferably, as illustrated in FIG. 4(b), the tip of the pointed tapered rib has a rounded shape with a radius R. Chipping at the tip can be prevented by adopting a rounded shape.

[0022] Since the inner rib-shaped flange 45 is a pointed tapered rib, an increase in weight can be suppressed. In addition, since the inner rib-shaped flange 45 is a pointed tapered rib, a casting draft angle can be ensured, and the inner rib-shaped flange 45 can be very easily separated from a casting die.

[0023] [Position of inner rib-shaped flange] As illustrated in FIG. 4(c), the inner rib-shaped flange 45 may protrude toward the inside of the vehicle body from midway in a height direction of the frame wall portion 47. Therefore, the inner rib-shaped flange 45 can protrude from any location on the frame wall portion 47.

[0024] [Side sill] Next, a structure of the side sill 20 will be described with reference to FIG. 5(a) and FIG. 5(b). As illustrated in FIG. 5(a), the side sill 20 is composed of a side sill outer 21 disposed on the outside of the vehicle body, a reinforcing member 22 disposed closer to the inside of the vehicle body than the side sill outer 21, and a side sill inner 23 disposed closer to the inside of the vehicle body than the reinforcing member 22. Incidentally, since the reinforcing member 22 is provided as necessary, the reinforcing member 22 is not an essential member.

[0025] It is preferable that the side sill outer 21, the reinforcing member 22, and the side sill inner 23 are press-formed articles made of a steel sheet. The press-formed article is also referred to as a pressed article.

[0026] [Side sill inner] The side sill inner 23 includes an inner wall portion 24 extending vertically; an inner roof portion 25 extending from an upper end of the inner wall portion 24 toward the outside of the vehicle body; an inner flange portion 26 extending upward from a tip of the inner roof portion 25; an inner protruding portion 27 protruding laterally toward the inside of the vehicle body from midway in a height direction of the inner wall portion 24; and an inner floor portion 28 extending from a lower end of the inner wall portion 24 toward the outside of the vehicle body.

[0027] As illustrated in FIG. 5(a), the inner protruding portion 27 is, for example, a cut-and-raised piece 32 obtained by making a cut 31 in the inner wall portion 24 and bending the cut 31 by approximately 90° as indicated by an arrow. The cut-and-raised piece 32 is formed at the same time during the pressing process.

[0028] As illustrated in FIG. 5(b), the side sill outer 21, the reinforcing member 22, and the side sill inner 23 are laterally stacked and joined to each other by spot welding nuggets 33 or the like, thereby obtaining the side sill 20.

[0029] [Effects of cut-and-raised piece] An opening 34 corresponding to the size of the cut-and-raised piece 32 is formed in the inner wall portion 24. The opening 34 serves as a passage for paint when electrodeposition coating is applied to the side sill 20. Since the opening 34 is sufficiently large, a sufficient amount of the paint flows in and out of the opening 34. As a result, electrodeposition coating on the side sill 20 is satisfactorily performed, and corrosion resistance of the side sill 20 is improved.

[0030] [Joining method for vehicle body rear portion structure at portion not including front end connecting member 60] A method for joining the side sill 20 and the rear frame 40 at the cross-section taken along line 6b-6b in FIG. 2 will be described with reference to FIG. 6(a) to FIG. 6(d).

[0031] As illustrated in FIG. 6(a), first, the rear frame 40 is moved from top to bottom relative to the side sill 20 that is stationary. In detail, a tip portion of the frame floor portion 49 is placed on the inner protruding portion 27 as indicated by arrow (1), the frame roof portion 48 covers the inner roof portion 25 from above as indicated by arrow (2), and the frame flange portion 44 is attached to the inner flange portion 26.

[0032] Then, as illustrated in FIG. 6(b), joining portions are joined by at least one of mechanical fastening, fusion welding, and adhesion (in this example, rivets 65). Mechanical fastening may be performed using bolts or screws in addition to the rivets 65. In addition, as fusion welding, friction stir welding, spot welding, laser welding, or the like is employed. In addition, adhesion is preferably performed using a one-component adhesive or a two-component adhesive.

[0033] As illustrated in FIG. 6(c), the side sill outer 21, the reinforcing member 22, the inner flange portion 26 of the side sill inner 23, and the frame flange portion 44 may be joined using, for example, the rivets 65. In addition, as illustrated in FIG. 6(d), the inner protruding portion 27 and the frame floor portion 49 may be joined using, for example, the rivets 65.

[0034] [Front end connecting member] Details of the front end connecting member 60 presented in FIG. 2 will be described with reference to FIG. 7(a) and FIG. 7(b). As illustrated in FIG. 7(a), the front end connecting member 60 is composed of a connecting portion floor 61; a connecting portion wall 62 rising from one end of the connecting portion floor 61; and a connecting portion roof 63. Preferably, the connecting portion floor 61 and the rising connecting portion wall 62 are integrally formed by press-forming a steel sheet into a shape with an L-shaped cross-section. In addition, the connecting portion roof 63 is obtained by pressforming a steel sheet into a shape with an I-shaped cross-section.

[0035] As illustrated in FIG. 7(b), the connecting portion roof 63 is placed on the connecting portion wall 62 to form a substantially U-shaped cross-section. However, both are not yet joined.

[0036] [Joining method for vehicle body rear portion structure at portion including front end connecting member 60] A method for joining the side sill 20, the rear frame 40, and the front end connecting member 60 at the cross-section taken along line 8b-8b in FIG. 2 will be described with reference to FIG. 8(a) to FIG. 8(e). As illustrated in FIG. 8(a), first, the connecting portion floor 61 and the connecting portion wall 62 are raised relative to the side sill 20 that is stationary, and the connecting portion floor 61 are brought into contact with the inner protruding portion 27 (arrow (3)).

[0037] Next, the rear frame 40 is moved from top to bottom. In detail, the tip portion of the frame floor portion 49 is placed on the inner protruding portion 27 as indicated by arrow (4), the frame roof portion 48 covers the inner roof portion 25 from above as indicated by arrow (5), and the frame flange portion 44 is attached to the inner flange portion 26. At the same time, the inner rib-shaped flange 45 is placed on an upper end of the connecting portion wall 62 (arrow (6)).

[0038] That is, the rear frame 40 is set on the connecting portion floor 61 and the connecting portion wall 62, which form an L-shaped cross-section with an open top, by moving the rear frame 40 from top to bottom.

[0039] Next, the connecting portion roof 63 is placed on the frame roof portion 48 as indicated by arrow (7), and one end of the connecting portion roof 63 is placed on the inner rib-shaped flange 45 as indicated by arrow (8). Then, as illustrated in FIG. 8(b), joining portions are joined by at least one of mechanical fastening, fusion welding, and adhesion.

[0040] As illustrated in FIG. 8(c), the side sill outer 21, the reinforcing member 22, the inner flange portion 26 of the side sill inner 23, and the frame flange portion 44 are joined using, for example, the rivets 65. In addition, as illustrated in FIG. 8(d), the inner protruding portion 27, the frame floor portion 49, and the connecting portion floor 61 are joined using, for example, the rivets 65. In addition, as illustrated in FIG. 8(e), the inner rib-shaped flange 45, the connecting portion wall 62, and the connecting portion roof 63 are joined using, for example, the rivets 65.

[0041] As illustrated in FIG. 8(b), the connecting portion floor 61 is shaped to align with the frame floor portion 49, the connecting portion wall 62 is shaped to align with the frame wall portion 47, and the connecting portion roof 63 is shaped to align with the frame roof portion 48. Therefore, the front end of the rear frame 40 can be surrounded by the front end connecting member 60.

[0042] [Height position of the inner protruding portion] As illustrated in FIG. 9(a), the inner protruding portion 27 is provided at a middle position in the height direction of the inner wall portion 24 to correspond to the rear frame 40 having a height dimension Hl. As illustrated in FIG. 9(b), for the rear frame 40 having a height dimension H2 greater than the height dimension Hl, the inner protruding portion 27 is provided at a lower position in the height direction of the inner wall portion 24.

[0043] That is, the inner protruding portion 27 can protrude at any height from midway in the height direction of the inner wall portion 24, and as a result, the height dimension of the rear frame 40 can be freely selected, and the degree of freedom in designing the rear frame 40 can be increased.

[0044] [Example of modification of inner protruding portion] As illustrated in FIG. 10(a), the inner protruding portion 27 may be a bracket 36 that is separate (separate component) from the inner wall portion 24. The bracket 36 is preferably an angle (angle steel), but may be a strip extending laterally (steel sheet with an I-shaped cross-section).

[0045] As illustrated in FIG. 10(b), the bracket 36 is joined to the inner wall portion 24 using mechanical coupling, fusion welding, or adhesion. The height position of the bracket 36 can be set arbitrarily. That is, the same effects as those in FIG. 9(a) and FIG. 9(b) are obtained.

[0046] [Function of center of rear frame] As illustrated in FIG. 11(a), the center of the rear frame 40 includes the frame wall portion 47 extending vertically; the frame roof portion 48 extending from the upper end of the frame wall portion 47 toward the outside of the vehicle body; the frame flange portion 44 extending upward from the tip of the frame roof portion 48; the frame floor portion 49 extending from the lower end of the frame wall portion 47 toward the outside of the vehicle body; and the inner rib-shaped flange 45 protruding laterally from the lower end of the frame wall portion 47 toward the inside of the vehicle body. Then, the rear wheel housing 12 is brought into contact with the frame flange portion 44 by moving the rear wheel housing 12 from the outside toward the inside of the vehicle body. In addition, a floor panel 16 is placed on the inner rib-shaped flange 45 by moving the floor panel 16 from top to bottom.

[0047] As illustrated in FIG. 11(b), the rear wheel housing 12 is joined to the frame flange portion 44 using, for example, the rivets 65, and the floor panel 16 is joined to the inner rib-shaped flange 45 using, for example, the rivets 65.

[0048] The invention can be summarized as follows based on the matters described above. As illustrated in FIG. 1, the invention is the vehicle body rear portion structure 10 including the side sill 20; and the rear frame 40 extending from the side sill 20 toward the rear of the vehicle body. As illustrated in FIG. 5(a), the side sill 20 includes the side sill outer 21 disposed on the outside of the vehicle body, and the side sill inner 23 disposed closer to the inside of the vehicle body than the side sill outer 21. The side sill inner 23 includes the inner wall portion 24 extending vertically; the inner roof portion 25 extending from the upper end of the inner wall portion 24 toward the outside of the vehicle body; the inner flange portion 26 extending upward from the tip of the inner roof portion 25, and the inner protruding portion 27 protruding laterally toward the inside of the vehicle body from midway in the height direction of the inner wall portion 24. As illustrated in FIG. 3(a), the front portion of the rear frame 40 includes the frame wall portion 47 extending vertically; the frame roof portion 48 extending from the upper end of the frame wall portion 47 toward the outside of the vehicle body; and the frame floor portion 49 extending from the lower end of the frame wall portion 47 toward the outside of the vehicle body such that the front portion has a U-shaped crosssection. As illustrated in FIG. 6(a), the tip portion of the frame floor portion 49 is placed on the inner protruding portion 27, and the frame roof portion 48 covers the inner roof portion 25 from above. As illustrated in FIG. 2, in this form, the front portion of the rear frame 40 is fixed to the side sill 20.

[0049] As illustrated in FIG. 6(a), the rear frame 40 is set on the side sill inner 23 simply by moving the rear frame 40 from top to bottom. Since no lateral movement is required, manufacturing becomes easier, and manufacturing costs can be reduced.

[0050] Preferably, as illustrated in FIG. 3(b), the rear frame 40 further includes the inner rib-shaped flange 45 protruding laterally from the upper end of the frame wall portion 47 toward the inside of the vehicle body. Alternatively, as illustrated in FIG. 4(c), the rear frame 40 further includes the inner rib-shaped flange 45 protruding laterally toward the inside of the vehicle body from midway in the height direction of the frame wall portion 47.

[0051] The strength of the rear frame 40 can be increased due to the reinforcing function of the inner rib-shaped flange 45. The load distribution characteristics in the event of a collision can be changed by changing the height position of the inner ribshaped flange 45. In addition, as illustrated in FIG. 8(b), when the front end connecting member 60 is provided, as illustrated in FIG. 8(e), a part of the front end connecting member 60 can be joined to the inner rib-shaped flange 45, so that the attachment of the front end connecting member 60 becomes easier.

[0052] Preferably, as illustrated in FIG. 10(a) and FIG. 10(b), the inner protruding portion 27 is the bracket 36 that is separate from the inner wall portion 24.

[0053] The bracket 36 can have any cross-sectional shape such as an L-shaped crosssection or an I-shaped cross-section extending laterally. Since the bracket 36 is a separate body, the bracket 36 can be attached to the inner wall portion 24 at any height. As a result, the degree of freedom in designing the rear frame 40 is increased.

[0054] Preferably, as illustrated in FIG. 5(a) and FIG. 59b), the inner protruding portion 27 is the cut-and-raised piece 32 obtained by making the cut 31 in the inner wall portion 24 and bending the cut 31.

[0055] Since the inner protruding portion 27 is formed integrally with the inner wall portion 24, it is not necessary to prepare a separate component. The inner protruding portion 27 can be provided in the inner wall portion 24 at any height. As a result, the degree of freedom in designing the rear frame 40 is increased. Furthermore, the opening 34 is formed in the inner wall portion 24 by cutting and raising. The opening 34 is used as an inlet and outlet for paint during electrodeposition coating.

[0056] Preferably, as illustrated in FIG. 2, the vehicle body rear portion structure 10 further includes the floor cross member 14 perpendicular to the side sill inner 23 and extending toward the inside of the vehicle body; and the front end connecting member 60 that connects the rear frame 40 and the floor cross member 14. As illustrated in FIG. 8(b), the front end connecting member 60 is composed of the connecting portion floor 61 shaped to align with the frame floor portion 49; the connecting portion wall 62 shaped to align with the frame wall portion 47; and the connecting portion roof 63 shaped to align with the frame roof portion 48. The front end connecting member 60 surrounds the front end of the rear frame 40.

[0057] As illustrated in FIG. 2, since the front end connecting member 60 connects the rear frame 40 and the floor cross member 14, the strength of the vehicle body rear portion structure 10 against a rear-end collision can be increased. The front end connecting member 60 can firmly fix the front portion of the rear frame 40, which is a die-cast article, to the side sill inner 23 and the floor cross member 14 that are pressed articles made of a steel sheet. In addition, as illustrated in FIG. 8(a), by moving the rear frame 40 downward, the front end connecting member 60 can be assembled, so that the assembly of the rear frame 40 and the front end connecting member 60 becomes easier.

[0058] Preferably, as illustrated in FIG. 11(a), the vehicle body rear portion structure 10 further includes the rear wheel housing 12; and the floor panel 16. The center of the rear frame 40 includes the frame wall portion 47 extending vertically; the frame roof portion 48 extending from the upper end of the frame wall portion 47 toward the outside of the vehicle body; the frame flange portion 44 extending upward from the tip of the frame roof portion 48; the frame floor portion 49 extending from the lower end of the frame wall portion 47 toward the outside of the vehicle body; and the inner rib-shaped flange 45 protruding laterally from the lower end of the frame wall portion 47 toward the inside of the vehicle body. As illustrated in FIG. 11(b), the rear wheel housing 12 is joined to the frame flange portion 44, and the floor panel 16 is joined to the inner rib-shaped flange 45.

[0059] The rear wheel housing 12 and the rear frame 40 can be assembled in a left-to-right direction, and the floor panel 16 and the rear frame 40 can be assembled in an up-to-down direction, so that the assembly of the rear portion of the vehicle body becomes easier and productivity is improved.

[0060] Preferably, the rear frame 40 is a die-cast article made of an aluminum alloy, and the front end connecting member 60 is a press-formed article made of a steel sheet. As illustrated in FIG. 2, the rear frame 40 and the front end connecting member 60 are joined by at least one of mechanical fastening, fusion welding, and adhesion (in the embodiment, the rivets 65).

[0061] An aluminum alloy and a steel sheet that are dissimilar materials can be joined.

[0062] Preferably, as illustrated in FIG. 3(a) and FIG. 3(b), the rear frame 40 includes the plurality of I-shaped ribs 43 that cross the U-shaped cross-section.

[0063] It is possible to increase the he strength and rigidity of the rear portion of the vehicle body while suppressing an increase in the weight of the rear frame 40. In the event of a rear-end collision, impact energy can be absorbed.

[0064] Preferably, as illustrated in FIG. 3(a) to FIG. 3(c), the rear frame 40 includes the inner rib-shaped flange 45 protruding laterally from the frame wall portion 47 toward the inside of the vehicle body. As illustrated in FIG. 4(a), the inner rib-shaped flange 45 is a pointed tapered rib, and the thickness tl of the base of the tapered rib is set to be approximately equal to the thickness t2 of the frame wall portion 47.

[0065] The strength and rigidity of the rear frame 40 can be increased by providing the inner rib-shaped flange 45. By providing the inner rib-shaped flange 45 over the entire length of the rear frame 40, it is possible to reduce the weight of the rear frame 40 while maintaining or improving the strength and rigidity of the rear frame 40.

[0066] In addition, as described with reference to FIG. 4(a) and FIG. 4(c), the inner ribshaped flange 45 can be provided on the frame wall portion 47 at any height position. Then, when the height position of the floor panel 16 illustrated in FIG. 11(b) is changed, the height position of the inner rib-shaped flange 45 can be easily changed to the height position of the floor panel 16. Asa result, the degree of freedom in designing the floor panel 16 is increased.

[0067] In addition, since the inner rib-shaped flange 45 is a pointed tapered rib, a draft angle is ensured and die release after casting becomes easier, so that the productivity of the cast rear frame is improved. INDUSTRIAL APPLICABILITY

[0068] The invention is suitable for the vehicle body rear portion structure including the side sill and the rear frame. EXPLANATIONS OF LETTERS OR NUMERALS

[0069] 10 VEHICLE BODY REAR PORTION STRUCTURE 12 REAR WHEEL HOUSING 14 FLOOR CROSS MEMBER 16 FLOOR PANEL 20 SIDE SILL 21 SIDE SILL OUTER 22 REINFORCING MEMBER 23 SIDE SILL INNER 24 INNER WALL PORTION 25 INNER ROOF PORTION 26 INNER FLANGE PORTION 27 INNER PROTRUDING PORTION 28 INNER FLOOR PORTION 31 CUT 32 CUT-AND-RAISED PIECE 36 BRACKET REAR FRAME I-SHAPED RIB FRAME FLANGE PORTION INNER RIB-SHAPED FLANGE FRAME WALL PORTION FRAME ROOF PORTION FRAME FLOOR PORTION FRONT END CONNECTING MEMBER CONNECTING PORTION FLOOR CONNECTING PORTION WALL CONNECTING PORTION ROOF

Claims

[Claim 1.] A vehicle body rear portion structure, comprising:a side sill; anda rear frame extending from the side sill toward a rear of a vehicle body,wherein the side sill includes a side sill outer disposed on an outside of the vehicle body, and a side sill inner disposed closer to an inside of the vehicle body than the side sill outer,the side sill inner includes an inner wall portion extending vertically, an inner roof portion extending from an upper end of the inner wall portion toward the outside of the vehicle body, an inner flange portion extending upward from a tip of the inner roof portion, and an inner protruding portion protruding laterally toward the inside of the vehicle body from midway in a height direction of the inner wall portion,a front portion of the rear frame includes a frame wall portion extending vertically, a frame roof portion extending from an upper end of the frame wall portion toward the outside of the vehicle body, and a frame floor portion extending from a lower end of the frame wall portion toward the outside of the vehicle body such that the front portion has a U-shaped cross-section,a tip portion of the frame floor portion is placed on the inner protruding portion, and the frame roof portion covers the inner roof portion from above, andin this form, the front portion of the rear frame is fixed to the side sill.[Claim 2.] The vehicle body rear portion structure according to claim 1,wherein the rear frame further includes an inner rib-shaped flange protruding laterally toward the inside of the vehicle body from the upper end of the frame wall portion or midway in a height direction of the frame wall portion.[Claim 3.] The vehicle body rear portion structure according to claim 1,wherein the inner protruding portion is a bracket that is separate from the inner wall portion.[Claim 4.] The vehicle body rear portion structure according to claim 1,wherein the inner protruding portion is a cut-and-raised piece obtained by making a cut in the inner wall portion and bending the cut.[Claim 5.] The vehicle body rear portion structure according to claim 1, further comprising:a floor cross member perpendicular to the side sill inner and extending toward the inside of the vehicle body; anda front end connecting member that connects the rear frame and the floor cross member,wherein the front end connecting member is composed of a connecting portion floor shaped to align with the frame floor portion, a connecting portion wall shaped to align with the frame wall portion, and a connecting portion roof shaped to align with the frame roof portion, andthe front end connecting member surrounds a front end of the rear frame.[Claim 6.] The vehicle body rear portion structure according to claim 1, further comprising:a rear wheel housing; anda floor panel,wherein a center of the rear frame includes a frame wall portion extending vertically, a frame roof portion extending from an upper end of the frame wall portion toward the outside of the vehicle body, a frame flange portion extending upward from a tip of the frame roof portion, a frame floor portion extending from a lower end of the frame wall portion toward the outside of the vehicle body, and an inner rib-shaped flange protruding laterally from the lower end of the frame wall portion toward the inside of the vehicle body, andthe rear wheel housing is joined to the frame flange portion, and the floor panel is joined to the inner rib-shaped flange.[Claim 7.] The vehicle body rear portion structure according to claim 1,wherein the rear frame includes a plurality of I-shaped ribs that cross the U-shaped cross-section.[Claim 8.] The vehicle body rear portion structure according to claim 5,wherein the rear frame is a die-cast article made of an aluminum alloy,the front end connecting member is a press-formed article made of a steel sheet, andthe rear frame and the front end connecting member are joined by at least one of mechanical fastening, fusion welding, and adhesion.INTERNATIONAL SEARCH REPORT International application No. PCT / JP2025 / 022586A. CLASSIFICATION OF SUBJECT MATTER B62D25 / 20(2006m)i;B62D25 / 08(2006.01)i FI: B62D25 / 20 F; B62D25 / 08 L According to International Patent Classification (IPC) or to both national classification and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) B62D25 / 20; B62D25 / 08 Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched Published examined utility model applications of Japan 1922-1996 Published unexamined utility model applications of Japan 1971-2025 Registered utility model specifications of Japan 1996-2025 Published registered utility model applications of Japan 1994-2025 Electronic data base consulted during the international search (name of data base and, where practicable, search terms used) C. DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. A JP 2016-002783 A (MAZDA MOTOR CORPORATION) 12 January 2016 (2016-01-12) entire text, all drawings 1-8 A A US 2015 / 0151795 Al (HONDA MOTOR CO., LTD.) 04 June 2015 (2015-06-04) entire text, all drawings US 2018 / 0170433 Al (HONDA MOTOR CO., LTD.) 21 June 2018 (2018-06-21) entire text, all drawings 1-8 1-8 A CN 111954618 A (HONDA MOTOR CO., LTD.) 17 November 2020 (2020-11-17) entire text, all drawings 1-8 | | Further documents are listed in the continuation of Box C. | f | See patent family annex. * Special categories of cited documents: “T” later document published after the international filing date or priority “A" document defining the general state of the art which is not considered date and not in conflict with the application but cited to understand the to be of particular relevance principle or theory underlying the invention “D" document cited by the applicant in the international application “X” document of particular relevance; the claimed invention cannot be “E" earlier application orpatent but published on or after the international considered novel or cannot be considered to involve an inventive step filing date when the document is taken alone “L" document which may throw doubts on priority claim(s) or which is “Y” document of particular relevance; the claimed invention cannot be cited to establish the publication date of another citation or other considered to involve an inventive step when the document is special reason (as specified) combined with one or more other such documents, such combination “O” document referring to an oral disclosure, use, exhibition or other being obvious to a person skilled in tile art means document member of the same patent family “P” document published prior to the international filing date but later than the priority date claimed Date of the actual completion of the international search 15 July 2025 Date of mailing of the international search report 29 July 2025 Name and mailing address of the ISA / JP Japan Patent Office (ISA / JP) 3-4-3 Kasumigaseki, Chiyoda-ku, Tokyo 100-8915 Japan Authorized officer Telephone No.INTERNATIONAL SEARCH REPORT Information on patent family membersInternational application No.PCT / JP2025 / 022586Patent document cited in search report Publication date (day / month / year) Patent family member(s) Publication date (day / month / year) JP 2016-002783 A 12 January 2016 (Family: none) US 2015 / 0151795 Al 04 June 2015 WO 2011 / 056962 Al entire text, all drawings CA 2778879 Al CN 102596692 A US 2018 / 0170433 Al 21 June 2018 (Family: none) CN 111954618 A 17 November 2020 US 2021 / 0107571 Al entire text, all drawings WO 2019 / 198753 Al

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