JP2008105529A - Vehicular sub-frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular sub-frame hardly causing thermal strain in respective members, while freely selecting a material of a collar 90. <P>SOLUTION: This vehicular sub-frame has a frame member 65 by extrusion molding and the collar 90 inserted into an opening part 80 of the frame member 65. A circular hole 81 and a slit 84 are formed in the frame member 65. A rib 94 is erected on an outer peripheral surface of a cylindrical body 91 of the collar 90. The rib 94 inserted into the slit 84 is joined to the frame member 65 by frictional agitating welding. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle subframe.

  The vehicle is provided with a pair of left and right side frames constituting a vehicle body skeleton member from the vehicle body front part to the vehicle body rear part. A subframe is connected to the side frame, and various devices of the vehicle are mounted on the subframe. The sub-frame is formed by joining a plurality of frame members by welding or the like.

Recently, a technique for forming a subframe by joining extruded frame members has been proposed.
Japanese Patent Laid-Open No. 2004-133867 discloses a vehicle member coupling in which corresponding end portions of a front side member and a rear side member continuous along the front-rear direction and corresponding end portions of a cross member along the vehicle width direction are coupled by a coupling bracket. The structure is described. Each of these members is formed of an aluminum alloy extruded material having a closed cross-sectional shape. The coupling bracket is formed by cutting an extruded material made of an aluminum alloy having the same cross section in the vertical direction. A square cylindrical frame is formed in the center of the coupling bracket, and a cylindrical nut portion (member fastening portion) is provided inside the frame.
JP-A-9-301216

However, in the technique described in Patent Document 1, since the coupling bracket including the nut portion is integrally formed of the extruded material, the coupling bracket is made of a lightweight magnesium alloy, and the nut portion is made of an aluminum alloy that can withstand the coupling torque. Is not easy.
In addition, the method of inserting and joining a separate color | collar to a frame member can be considered. In this case, it is necessary to join the upper surface and the lower surface of the frame member along the outer periphery of the collar by gas welding or arc welding. However, with this technique, the amount of heat generated during welding is large, and each member may be distorted by heat.

  Accordingly, it is an object of the present invention to provide a vehicular subframe in which a color material can be freely selected and thermal distortion is unlikely to occur in each member.

  In order to solve the above-mentioned problem, the invention according to claim 1 includes an extruded frame member (for example, frame member 65 in the embodiment) and a collar (for example, collar 90 in the embodiment) inserted into the frame member. ) Including a slit (for example, a slit 84 in the embodiment) formed in the frame member, and an outer peripheral surface of the collar by extrusion molding. A rib (for example, the rib 94 in the embodiment) is erected, and the rib inserted into the slit is joined to the frame member by welding.

  The invention according to claim 2 is characterized in that the welding is friction stir welding.

  In the invention according to claim 3, the slits (for example, the slits 84 and 184 in the embodiment) are respectively formed in the plurality of frame members (for example, the frame members 65 and 165 in the embodiment), and The ribs inserted into the slit (for example, the ribs 94 and 194 in the embodiment) are joined to the plurality of frame members by friction stir welding.

  According to the first aspect of the present invention, since the collar can be fixed to the frame member easily and reliably, it is possible to employ a color separate from the frame member. Therefore, the color material can be freely selected. Further, the frame member and the collar can be easily formed by extrusion molding. Furthermore, since the rib is welded to the frame member at a position away from the collar, it is not necessary to perform welding along the outer periphery of the collar. Therefore, even if the collar is small, it can be easily joined.

  According to the second aspect of the present invention, since the rib is joined to the frame member by friction stir welding with a small amount of heat generation, the occurrence of thermal distortion in each member can be prevented.

  According to the third aspect of the present invention, since the ribs standing on the collar are joined to the plurality of frame members, the plurality of frame members can be joined to each other. This eliminates the need for a joint member or the like for joining a plurality of frame members, and can reduce manufacturing costs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a case where a subframe according to the present invention is applied to a subframe on which a fuel cell is mounted in a fuel cell vehicle will be described as an example.

(First embodiment)
FIG. 1 is an explanatory view of a side surface of a vehicle, and FIG. 2 is a cross-sectional view taken along line AA of FIG. As shown in FIGS. 1 and 2, a fuel cell vehicle has a fuel cell stack 12 that generates electricity by an electrochemical reaction between hydrogen and oxygen, and is mounted under the floor of a vehicle body. Drives by driving the drive motor. The fuel cell stack 12 is a well-known polymer electrolyte fuel cell (PEMFC) in which a number of unit cells (unit fuel cells) are stacked, for example, and supplies hydrogen gas as a fuel gas to the anode side, and the cathode side By supplying air containing oxygen as an oxidant gas, electric power is generated by an electrochemical reaction and water is generated.

  As shown in FIG. 1, the fuel cell vehicle is provided with a pair of left and right side frames 2 that form a vehicle body skeleton member below the floor panel 1 from the vehicle body front portion to the vehicle body rear portion. As shown in FIG. 2, a side sill 5 is joined to the outer walls 3 of the left and right side frames 2 via an outrigger 4. A cross member (not shown) which is a vehicle body skeleton member is connected to the side frame 2 in the vehicle width direction.

As shown in FIG. 1, a front sub-frame 11 is attached to the motor room 10 at the front of the vehicle body from the lower side with respect to the side frame 2. The front subframe 11 is equipped with a compressor 13 for supplying air to the fuel cell stack 12, a pump motor unit 15 including a driving motor 14 for traveling, and the like.
A rear sub-frame 16 is attached to the rear portion of the vehicle body from the lower side with respect to the side frame 2. In addition to the wheels and suspension, the rear subframe 16 is mounted with a hydrogen tank 17 and a storage battery 18 that store hydrogen as fuel of the fuel cell stack 12.

On the side frame 2, the floor panel 1 is joined. The front end portion of the floor panel 1 rises to the front and continues to the dash lower 1a, and the rear end portion of the floor panel 1 extends to a position covering the upper portion of the hydrogen tank 17 of the rear subframe 16.
The floor panel 1 is formed with a floor tunnel 22 that bulges upward between the left and right front seats 20 and rear seats 21 from the lower end of the dash lower 1a toward the rear of the vehicle body. The floor tunnel 22 bulges further upward between the left and right front seats 20 and 20 to form a center console 23.

  As shown in FIG. 2, a reinforcement 26 that forms a triangular cross section is joined to a lower surface portion from the left and right rising portions 24 of the floor tunnel 22 to the side wall 25 of the center console 23. The console 23 is reinforced. A center frame 27 having a closed cross-sectional structure is joined to the lower surface of the reinforcement 26 along the longitudinal direction of the vehicle body. A reinforcing frame 28 having a closed cross-sectional structure is joined to the corner portion between the inner wall of the side frame 2 and the floor panel 1 along the longitudinal direction of the vehicle body.

  Subframes 40 are attached to the lower surfaces of the center frame 27 and the reinforcing frame 28. As shown in FIG. 1, the fuel cell stack 12 and its accessories 19 are mounted on the subframe 40. The fuel cell 12 and the accessories 19 are disposed in the center console 23, that is, below the floor panel 1 that is outside the passenger compartment. Accordingly, the fuel cell is isolated from the passenger's living space by the floor panel 1 (center console 23).

(Sub-frame)
FIG. 3 is a perspective view of the subframe. The sub frame 40 includes a pair of sub center frames 44, 44 extending in the vehicle front-rear direction. The sub-center frames 44 and 44 are connected to the lower side of the center frame described above. The pair of sub-center frames 44, 44 are connected by a front sub-cross frame 41 and a rear sub-cross frame 42 arranged in the vehicle width direction. Thereby, the sub-frame 40 is comprised by the frame shape frame | skeleton. The rear end portions of the sub-center frames 44, 44 extending rearward from the rear sub-cross frame 42 are connected by an end frame 45 disposed in the vehicle width direction.
Intermediate frames 47, 47 extend from the sub center frames 44, 44 toward the outside in the vehicle width direction between the front and rear sub cross frames 41, 42. The front ends of the intermediate frames 47 and 47 are connected to the lower side of the reinforcing frame described above.

Various frames constituting the sub-frame 40 are constituted by a frame member 65 and a joint member 70 disposed at an intersection of the plurality of frame members 65. Hereinafter, the frame member 65 and the joint member 70 in the P part will be described as an example, but the other parts are configured in the same manner.
FIG. 4 is an enlarged exploded view of a portion P in FIG. As shown in FIG. 4, the frame member 65 is formed in a rectangular closed cross-sectional structure by extruding a metal material such as aluminum. The frame member 65 has a hollow structure having an opening 66 at the end.

  The joint member 70 is formed into a solid structure using a metal material such as a magnesium alloy. The joint member 70 includes a rectangular parallelepiped main body 71. On the side surface of the main body 71, a fitting portion 76 that fits into the opening 66 of the frame member 65 is formed to protrude. And the fitting part 76 of the joint member 70 is inserted in the opening 66 of the frame member 65, and the sub-frame is assembled. Further, a fitting portion 69 between the fitting portion 76 of the joint member 70 and the frame member 65 is joined by friction stir welding (hereinafter referred to as “FSW”) described later.

  A through hole (not shown) is formed through the body portion 71 of the joint member 70 in the vertical direction, and a collar 74 is inserted into the through hole. The collar 74 is integrally formed in a cylindrical shape from a metal material such as an aluminum material that is harder (higher buckling strength) than the magnesium alloy constituting the joint member 70. A mounting hole 72 is formed along the central axis of the collar 74. By passing a bolt through the mounting hole 72 from below, the subframe 40 is fastened to the center frame 27 and the reinforcing frame 28 as shown in FIG.

(Color)
FIG. 5A is an enlarged exploded view of a portion Q in FIG. 3, and FIG. 5B is a cross-sectional view taken along line BB ′ in FIG. As shown in FIG. 5A, the collar 90 for attaching the sub-frame to the vehicle body is inserted into the frame member 65 in addition to the joint member. In FIG. 5A, three collars 90 are inserted into the frame member 65 along the extending direction of the frame member 65.

  The collar 90 is formed by extruding a hard metal material such as aluminum having high buckling strength. By adopting a material having a high buckling strength, it becomes possible to withstand the fastening torque of the bolt inserted into the mounting hole 92 of the collar 90 and to prevent the bolt from loosening. Moreover, the manufacturing cost of the collar 90 can be reduced by extrusion molding.

  The collar 90 includes a cylindrical body 91 in which an attachment hole 92 is formed, and plate-like ribs 94 that are provided on the outer peripheral surface of the cylindrical body 91 and extend along the axial direction of the cylindrical body 91. ing. The rib 94 is formed at the same height as the cylindrical body 91. In the present embodiment, the pair of ribs 94 are erected in a state where they are shifted from each other by 180 °. The pair of ribs 94 is erected toward both sides in the extending direction of the frame member 65 into which the cylindrical collar 90 is inserted.

  On the other hand, the frame member 65 has an opening 80 into which the collar 90 is inserted. The opening 80 includes a circular hole 81 into which the cylindrical body 91 of the collar 90 is inserted, and a slit 84 into which the rib 94 of the collar 90 is inserted. In the present embodiment, a pair of slits 84 is formed corresponding to the pair of ribs 94 of the collar 90. The pair of slits 84 are extended from the circular hole 81 toward both sides in the extending direction of the frame member 65.

  As shown in FIG. 5B, the above-described opening 80 is formed in the first wall 65a of the pair of walls 65a and 65b that are opposed to each other in the vertical direction in the frame member 65. The second wall 65b of the pair of walls 65a and 65b is formed with a through hole 88 having substantially the same diameter as the attachment hole 92 formed in the collar 90.

  Returning to FIG. 5A, the collar 90 is inserted into the opening 80 formed in the F portion of the frame member 65. Specifically, the cylindrical body 91 of the collar 90 is inserted into the circular hole 81 of the opening 80, and the rib 94 of the collar 90 is inserted into the slit 84 of the opening 80. The G portion of the frame member 65 is in a state immediately after the collar 90 is inserted. The E portion of the frame member 65 is a state in which the rib 94 of the collar 90 and the frame member 65 are joined by FSW.

  As shown in FIG. 5B, the second end surface 90b of the collar 90 inserted into the frame member 65 is in contact with the inner surface of the second wall 65b of the frame member 65 (second contact portion 69b). Thereby, the attachment hole 92 of the collar 90 and the through hole 88 of the frame member 65 are continuously arranged in the axial direction. On the other hand, the first end surface 90 a of the collar 90 is arranged in the same plane as the outer surface of the first wall 65 a of the frame member 65. Accordingly, a first contact portion 69 a between the rib 94 of the collar 90 and the first wall 65 a of the frame member 65 is formed between the side surface of the rib 94 of the collar 90 and the inner surface of the slit of the frame member 65. . And these 1st contact parts 69a and 2nd contact part 69b are joined by FSW.

  For the FSW, a cylindrical stirring rod 100 having a protrusion 101 at the center is used. Then, the stirring rod 100 is rotated around the central axis while pressing the stirring rod 100 toward the contact portions 69a and 69b described above. As a result, frictional heat is applied to the contact portions 69a and 69b, and a plasticized and viscous layer is formed on the material. When the stirring rod 100 is advanced along the contact portions 69a and 69b, the contact portions 69a and 69b are sequentially plasticized. When the plasticized material is solidified, the FSW joint 110 is formed at the contact portions 69a and 69b.

As described in detail above, in the vehicular subframe according to the first embodiment, the collar 90 is inserted into the frame member 65 and the rib 94 and the frame member 65 erected on the collar 90 are joined by FSW. It was. According to this configuration, the collar 90 can be easily and reliably fixed to the frame member 65, so that it is possible to employ a collar 90 that is separate from the frame member 65. Therefore, the material of the collar 90 can be freely selected. For example, if a material that is harder (higher buckling strength) than the constituent material of the frame member 65 is selected as the constituent material of the collar 90, loosening of bolts and the like inserted into the mounting holes 92 of the collar 90 can be prevented.
For joining the collar 90 to the frame member 65, FSW having a small amount of heat generation was adopted instead of gas welding or arc welding having a large amount of heat generation. Thereby, generation | occurrence | production of the thermal distortion in the frame member 65 or the collar 90 can be prevented.

  In addition, since the end surface of the cylindrical body 91 of the collar 90 becomes a seating surface of the fastening bolt, when performing FSW along the peripheral edge of the end surface of the cylindrical body 91, is the thickness of the cylindrical body 91 increased? Alternatively, it is necessary to correct the end surface of the cylindrical body 91 after performing the FSW. However, the increase in the thickness of the cylindrical body 91 increases the vehicle weight, and the modification of the end face of the cylindrical body 91 complicates the manufacturing process. On the other hand, in the first embodiment, since FSW is performed along the rib 94 erected on the outer peripheral surface of the cylindrical body 91 of the collar 90, it is not necessary to increase the thickness of the cylindrical body 91. An increase in vehicle weight can be suppressed. In addition, even if the FSW is performed, no deformation or the like occurs on the end surface of the cylindrical body 91, so that it is not necessary to modify the end surface, and the manufacturing process can be prevented from becoming complicated.

  In order to increase the section modulus of the frame member having a hollow structure, an intermediate rib may be provided on the inner surface of the frame member. If an opening for inserting a collar is formed in the frame member, the middle rib is cut and the section modulus of the frame member is lowered. On the other hand, in the first embodiment, since the rib 94 of the collar 90 is FSW joined to the frame member 65, the section modulus of the frame member 65 can be increased. Thereby, plastic deformation etc. of a frame member can be prevented.

  Further, as shown in FIG. 5A, it is desirable that the plurality of collar ribs inserted into the frame member 65 abut (or approach) each other. Specifically, the tip of the rib 94e on the F portion side of the collar 90 inserted into the E portion of the frame member 65 and the tip of the rib 94f on the E portion side of the collar 90 inserted into the F portion contact each other. Ribs and slits are formed so as to be (or close). Thereby, the section modulus can be increased over substantially the entire area of the frame member 65. Further, the FSW along the rib 94e of the E portion and the FSW along the rib 94f of the F portion can be performed continuously, and the manufacturing time can be shortened and the manufacturing cost can be reduced.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 6 is an explanatory diagram of the vehicle subframe according to the second embodiment, and is an enlarged view of a portion corresponding to a P portion in FIG. 2. In the first embodiment shown in FIG. 4, the plurality of frame members 65 are joined via the joint member 70, but in the second embodiment shown in FIG. 6, the plurality of frame members 65 and 165 are joined via the collar 190. Join. In the second embodiment, the second frame member 165 is joined to one side of the pair of side walls of the long first frame member 65. Note that detailed description of portions having the same configuration as in the first embodiment is omitted.

  As shown in FIG. 6A, the collar 190 includes three ribs 94 and 194 erected on the outer peripheral surface of the cylindrical body 91. Among these, the pair of first ribs 94 are erected toward both sides in the extending direction of the first frame member 65 into which the collar 190 is inserted. The second rib 194 is erected in the extending direction of the second frame member 165 joined to the first frame member 65. Note that the pair of first ribs 94 are disposed in a state of being shifted from each other by 180 °, and the second ribs 194 are disposed in a state of being shifted from the pair of first ribs 94 by 90 °. Since this collar 190 has a constant cross-sectional shape in the direction perpendicular to the axis, it can be formed at low cost by extrusion molding.

  On the other hand, the first frame member 65 has an opening 180 into which the collar 190 is inserted. The opening 180 includes a circular hole 81 into which the cylindrical body 91 of the collar 190 is inserted, a pair of first slits 84 into which the pair of first ribs 94 are inserted, and a second slit 184 into which the second rib 194 is inserted. I have. The pair of first slits 84 are extended from the circular hole 81 toward both sides in the extending direction of the first frame member 65. The second slit 184 extends from the circular hole 81 in the extending direction of the second frame member 165. The second slit 184 extends not only on the upper wall of the first frame member 65 but also on the side wall. Further, the second slit 184 is also formed on the upper wall of the second frame member 165.

  6B, the collar 190 is inserted into the opening 180 formed in the first frame member 65 and the second frame member 165. As shown in FIG. Then, along the ribs 94 and 194 of the collar 190, FSW joint portions 110 are formed on the upper and lower surfaces of the frame members 65 and 165. As a result, the first rib 94 of the collar 190 is joined to the first frame member 65, and the second rib 194 of the collar 190 is joined to the second frame member 165. Therefore, the first frame member 65 and the second frame member 165 are joined via the collar 190. Thereby, it becomes possible to join the some frame members 65 and 165 without going through a joint member, and can reduce a number of parts and can reduce manufacturing cost.

(Modification)
FIG. 7 is an explanatory diagram of a vehicle subframe according to a modification of the second embodiment. In the second embodiment, the second frame member 165 is joined to one side of the pair of side walls of the first frame member 65. However, in this modified example, a pair of second frames is provided on both sides of the pair of side walls of the first frame member 65. The member 165 is joined. Note that detailed description of portions having the same configuration as in the first embodiment or the second embodiment is omitted.

  As shown in FIG. 7A, the collar 290 includes four ribs 94 and 194 erected on the outer peripheral surface of the cylindrical body 91. Of these, the pair of first ribs 94 are erected toward both sides in the extending direction of the first frame member 65 into which the collar 290 is inserted. In addition, the pair of second ribs 194 is erected in the extending direction of the pair of second frame members 165 joined to the first frame member 65. The pair of first ribs 94 are arranged in a state of being shifted from each other by 180 °, the pair of second ribs 194 are also arranged in a state of being shifted from each other by 180 °, and the first ribs 94 and the second ribs 194 are mutually connected. Are arranged in a state shifted by 90 °. Since the collar 290 has a constant cross-sectional shape in the direction perpendicular to the axis, it can be formed at low cost by extrusion molding.

  On the other hand, the first frame member 65 has an opening 280 into which the collar 290 is inserted. The opening 280 includes a circular hole 81 into which the cylindrical body 91 of the collar 290 is inserted, a pair of first slits 84 into which the pair of first ribs 94 are inserted, and a pair of second slits into which the pair of second ribs 194 are inserted. And a slit 184. The pair of first slits 84 are extended from the circular hole 81 toward both sides in the extending direction of the first frame member 65. The pair of second slits 184 are extended from the circular hole 81 toward the extending direction of the pair of second frame members 165. The second slit 184 extends not only on the upper wall of the first frame member 65 but also on the pair of side walls of the first frame member 65. Further, the second slit 184 is also formed on the upper walls of the pair of second frame members 165.

  As shown in FIG. 7B, the collar 290 is inserted into the opening 280 formed in the first frame member 65 and the pair of second frame members 165. Then, along the ribs 94 and 194 of the collar 290, the FSW joint 110 is formed on the upper and lower surfaces of the frame members 65 and 165. As a result, the pair of first ribs 94 of the collar 290 are joined to the first frame member 65, and the pair of second ribs 194 of the collar 290 are joined to the pair of second frame members 165. Therefore, the first frame member 65 and the pair of second frame members 165 are joined via the collar 290. Thereby, it becomes possible to join the some frame members 65 and 165 without going through a joint member, and can reduce a number of parts and can reduce manufacturing cost.

The present invention is not limited to the embodiment described above.
For example, in the embodiment, the sub-frame in which the fuel cell is mounted at the center of the vehicle has been described as an example. However, the present invention can be applied to a sub-frame in which devices other than the fuel cell are mounted in the front or rear of the vehicle. In addition, the shape of the subframe is not limited to the shape of the above embodiment, and can be changed as appropriate.

It is explanatory drawing of a vehicle side surface. It is sectional drawing in the AA of FIG. It is a perspective view of a subframe. It is an expansion exploded view of the P section of FIG. (A) is an expansion exploded view of the Q section of FIG. 3, (b) is a sectional view taken along line BB ′ of (a). It is explanatory drawing of the sub-frame for vehicles which concerns on 2nd Embodiment. It is explanatory drawing of the sub-frame for vehicles which concerns on the modification of 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 40 ... Subframe for vehicles 65 ... Frame member, 1st frame member 80 ... Opening part 81 ... Circular hole 84 ... Slit, 1st slit 90 ... Collar 91 ... Cylindrical body 94 ... Rib, 1st rib 165 ... 2nd frame Member 184 ... second slit 190 ... collar 194 ... second rib

Claims (3)

A vehicular sub-frame comprising an extruded frame member and a collar inserted into the frame member,
A slit is formed in the frame member,
Ribs are erected on the outer peripheral surface of the collar by extrusion molding,
The sub-frame for vehicles, wherein the rib inserted into the slit is joined to the frame member by welding.   The vehicle subframe according to claim 1, wherein the welding is friction stir welding. The slit is formed in each of the plurality of frame members,
The vehicular sub according to claim 1, wherein the ribs inserted into the slits of the plurality of frame members are joined to the plurality of frame members by friction stir welding. flame.

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