JP4592366B2 - Vehicle rear structure - Google Patents

Description

  The present invention relates to a vehicle rear structure, and more particularly to a vehicle rear structure in an electric vehicle such as a fuel cell vehicle.

As a vehicle rear structure in a conventional electric vehicle, a fuel cell main body, a hydrogen tank, etc. are provided on a subframe comprising a buckling deformed portion (side member) and a buckled deformed portion (attached to the rear end of the side member and supporting the fuel cell). Is known, and the impact of a rear collision (hereinafter referred to as rear collision) is absorbed by the subframe (see, for example, Patent Document 1).
JP 2003-127907 A (page 2-4, FIG. 5)

  However, the vehicle body structure disclosed in Japanese Patent Laid-Open No. 2003-127907 has a sub-frame configured by combining a plurality of frame members, so that the use of additional members increases the cost and the structure is complicated. Increased weight and man-hours were inevitable.

The vehicle rear structure according to the present invention is a vehicle rear structure in which an electric system unit is arranged at the rear of the vehicle. An extension portion is provided at the rear of the rear side member, and a rear cross is provided on the vehicle front side and rear upper side of the rear suspension member. A member is disposed, the electric system unit is fixed on the rear cross member, a front end portion of the electric system unit is fixed to an upper portion of the rear cross member on the front side, and a rear end portion of the electric system unit is fixed. The rear suspension member is fixed to the upper part of the rear cross member, and the rear suspension member extends in the vehicle width direction and is disposed in the front-rear direction, and the rear suspension members extend in the front-rear direction. The connecting portion is connected to the rear side member of the rear suspension member. It is intended to be subject matter of the vehicle width direction inner side and than the mounting portion than the rear side member are connected to portions located below.

According to the vehicle rear portion structure according to the present invention, when an impact from the extension portion deformed by rear-end collision is input, the energy of the impact is absorbed by the structure of the frame-shaped comprising a high rear cross member and Li A suspension member rigid Therefore, sufficient vehicle body rigidity can be ensured even during a rear collision. In particular, since an additional member for configuring the subframe is not required as in the conventional example, an increase in cost can be prevented. Further, since the structure is simplified, it is possible to provide a vehicle rear structure that does not increase in weight or man-hours and is excellent in weight reduction and productivity of the vehicle body.

  Hereinafter, as a best mode for carrying out a vehicle rear structure according to the present invention, an embodiment in which the present invention is applied to a fuel cell vehicle will be described with reference to the drawings.

  1 and 2 show a vehicle rear structure according to the first embodiment. FIG. 1 is a schematic sectional view showing a configuration around a fuel tank arranged at the rear of the vehicle, and FIG. 2 is a schematic bottom view of FIG. is there. In FIG. 1, the rear side member and the rear suspension member (and the surrounding parts) show cross sections along the center line of the vehicle. Further, hatching or the like showing a cross section is omitted. The embodiment will be described below with reference to FIGS. 1 and 2 (with appropriate figure numbers).

  The vehicle rear portion structure 10 in this embodiment includes rear side members 11 and 12 disposed on the left and right sides of the vehicle in the front-rear direction, and extension members (extension portions) 13 connected to the rear portions of the left and right rear side members 11 and 12. , 14 and rear cross members 15, 16 connected across the left and right rear side members 11, 12 as main parts. Rear suspension members 17, 18 are attached below the rear cross members 15, 16. ing. Here, as shown in FIG. 1, the rear cross members 15 and 16 are disposed on the front and rear upper sides of the rear suspension members 17 and 18, respectively.

  The fuel tank 19 is held by a tank frame 20 provided at the lower part of the vehicle body. The front portion of the tank frame 20 is connected to the lower portions on the front end sides of the left and right rear side members 11 and 12, and the rear portion is connected to the lower portion between the rear cross members 15 and 16. The fuel tank 19 is fixed by a binding belt (not shown) and a fixed side belt provided on the tank frame 20.

  In the present embodiment, as shown in FIG. 1, the rear floor 22 is formed so as to be one step higher than the front floor 21, and a rear seat 23 is installed on the upper front side of the rear floor 22. A front side of the rear floor 22 on which the rear seat 23 is installed is formed to bulge out in a box shape toward the inside of the vehicle, and a fuel tank 19 held by the tank frame 20 is disposed below the rear floor 22.

  The secondary battery (second electric system unit) 24 is housed in a box-shaped battery case 30 and is installed on the back surface of the rear seat cushion 23a via a mounting bracket and a mounting bolt (not shown). In the present embodiment, the rear seat cushion 23a is mounted so as to tilt backward toward the rear of the vehicle, and the secondary battery 24 is also attached in parallel with the rear surface of the rear seat cushion 23a.

  The DC / DC converter (first electric system unit) 25 is fixed to the upper portions of the rear cross members 15 and 16 via mounting brackets and mounting bolts (not shown). The DC / DC converter 25 receives DC power from a fuel cell stack (not shown) and the secondary battery 24, and outputs the converted DC power to a device such as an inverter (not shown). A DC / DC converter harness (harness) 26 is connected. The DC / DC converter harness 26 is taken out from the space of the rear floor 22 surrounded by the rear cross members 15 and 16 and the left and right rear side members 11 and 12 to the lower part of the vehicle (in FIG. 1 and FIG. Only the strain is shown).

  According to the vehicle rear structure 10 configured as described above, the DC / DC converter 25 is fixed to the upper portions of the rear cross members 15 and 16, and the rear cross members 15 and 16 are connected to the vehicle of the rear suspension members 17 and 18. Since the frame-like structure composed of the rear cross members 15 and 16 and the rear side members 11 and 12 is arranged on the front side and the upper rear side, the extension members 13 and 14 deformed by the rear impact are high. When an impact is input from the side, the energy of the impact can be efficiently absorbed, and bending of the left and right rear side members 11 and 12 can be prevented. Similarly, since the DC / DC converter 25 is fixed to the upper part of the rear cross members 15 and 16, when the impact is input, the energy of the impact is efficiently absorbed by the structure, so that the DC / DC Damage to the converter 25 can be prevented. Further, since the impact of the rear impact can be absorbed by the existing structure, it is possible to prevent an increase in cost due to the use of the additional member as in the case where the subframe is configured by combining a plurality of frame members. Furthermore, since the structure is simplified, it is possible to provide a vehicle rear structure that does not increase in weight or man-hours and is excellent in weight reduction and productivity of the vehicle body.

  Further, since the place where the DC / DC converter 25 is located is close to the crushable zone at the time of the rear collision, the DC / DC converter harness 26 connected to the DC / DC converter 25 at the time of the rear collision may be damaged or disconnected. High nature. In this embodiment, the DC / DC converter harness 26 is configured by a space of the rear floor 22 surrounded by the rear cross members 15 and 16 and the rear side members 11 and 12, that is, the rear cross members 15 and 16 and the rear side members 11 and 12. Since the frame-shaped structure is taken out from the lower part of the vehicle, it is possible to suppress the collapse of the vehicle body between the cross members when an impact due to a rear collision is input. Therefore, the possibility that the DC / DC converter harness 26 is damaged or disconnected is reduced, and electrical safety at the time of rear collision can be ensured.

  Further, the DC / DC converter 25 is fixed to the upper part of the rear cross members 15 and 16 in a horizontally placed state, and the secondary battery 24 is installed on the back surface of the rear seat cushion 23a in the form as shown in FIG. When a rear collision occurs, the box-shaped DC / DC converter 25 does not lift upward and moves horizontally in front of the vehicle. Therefore, even if the DC / DC converter 25 moves from its original fixed position due to an impact at the time of rear collision, the front end of the DC / DC converter 25 only collides with the lower part of the battery case 30 and is stored inside. Since there is little damage to the secondary battery 24, it is possible to ensure electrical safety at the time of rear collision. And since such an effect can be exhibited without adding components, reduction of cost and reduction of the number of components can be achieved.

  Next, a cover structure that covers the secondary battery 24 and the DC / DC converter 25 will be described.

  As shown in FIG. 1, a battery unit cover (battery cover) 27 is provided behind the secondary battery 24, and a luggage board 28 is provided above the DC / DC converter 25. The battery unit cover 27 has a shape such that the cover vertical surface 27 c is perpendicular to the rear floor 22 when installed, and a space 100 is formed between the cover vertical surface 27 c and the rear surface of the secondary battery 24. The battery unit cover 27 is attached by the following structure.

  The upper end portion 27a on the rear seat side of the battery unit cover 27 is formed in a substantially U shape, and is configured to engage with a hook portion 23b provided on the upper back of the rear seat cushion 23a when the cover is attached. On the other hand, the floor side lower end portion 27b of the battery unit cover 27 is formed in a substantially L shape so that the cover body is held on the upper surface of the DC / DC converter 25 when the cover is attached. Here, the lower end portion 27b of the battery unit cover 27 is only in contact with the upper surface of the DC / DC converter 25 and is not fixed by bolts or the like. A luggage board 28 is placed so as to overlap the lower end portion 27 b of the battery unit cover 27, and the vehicle front side of the luggage board 28 is fixed to the DC / DC converter 25 by mounting bolts 29. As a result, the lower end portion 27 b of the battery unit cover 27 is fixed on the DC / DC converter 25 and below the front end portion 28 a of the luggage board 28.

  According to the cover structure configured as described above, since the battery unit cover 27 is provided so as to cover the back surface of the secondary battery 24, the load mounted in the luggage room is directly attached to the secondary battery 24. Contact can be prevented. Further, since the light impact caused by the movement of the load is absorbed by the battery unit cover 27, the contact with the secondary battery 24 can be prevented. Further, since the space 100 is secured between the cover vertical surface 27c of the battery unit cover 27 and the rear surface of the secondary battery 24, the luggage in the luggage room moves forward rapidly and the battery unit cover 27 Even if it breaks through, there is a distance until the battery case 30 is reached, so that the damage range of the secondary battery 24 due to the load can be limited to a small range. Further, in the cover structure of the present embodiment, it is not necessary to add a battery protection member in addition to the battery unit cover 27, so that a reduction in cost and the number of components can be achieved.

  Furthermore, since the space 100 is formed between the cover vertical surface 27c of the battery unit cover 27 and the back surface of the secondary battery 24, the cover vertical surface 27c is formed so as to be parallel to the back surface of the secondary battery 24. Compared with, the heat dissipation efficiency of the secondary battery 24 can be improved. Although not shown in FIG. 1, the heat dissipation efficiency can be further improved by forming a slit for ventilation in the battery unit cover 27.

  Further, since the lower end portion 27b of the battery unit cover 27 is fixed on the DC / DC converter 25 and below the front end portion 28a of the luggage board 28, when accessing the secondary battery 24, the luggage board 28 is first attached. It is necessary to loosen and remove the mounting bolt 29 and then lift and remove the battery unit cover 27 upward. In general, since the voltage of the secondary battery 24 and the DC / DC converter 25 gradually decreases from power off, it is not preferable to touch the secondary battery 24 and the DC / DC converter 25 immediately after the power is turned off. In particular, since it takes time for the secondary battery 24 to turn off after the power is turned off, it is required that the user does not touch the user carelessly before the voltage drops. In the cover structure of the present embodiment, the battery unit cover 27 cannot be removed unless the luggage board 28 is removed. Therefore, when the user accesses the secondary battery 24, the above removal procedure is performed. Therefore, it is possible to secure a time from when the power is turned off until the voltage drops sufficiently. Therefore, when the user accesses the secondary battery 24 after the power is turned off, the voltage of the secondary battery 24 is sufficiently lowered, and even if the user touches a terminal or the like carelessly, an electric shock, etc. The danger of can be avoided.

  In addition, when a special head-shaped (or standard) bolt is used as the mounting bolt 29, the user cannot easily access the secondary battery 24 using an in-vehicle tool or the like, so that safety is further improved. be able to.

  In addition, when assembling a normal vehicle, the battery unit cover 27 is mounted with the secondary battery 24 and the DC / DC converter 25 attached, so that the lower end portion 27b of the battery unit cover 27 is directly attached to the rear floor 22. When the structure is fixed, the distance between the secondary battery 24 and the DC / DC converter 25 is short, so that the visibility of the operator is poor, and it is difficult to secure a work space for mounting. However, in the cover structure of this embodiment, the battery unit cover 27 is fixed on the DC / DC converter 25 by the front end portion 28a of the luggage board 28, so that the visibility of the worker is improved and the work space for installation is improved. Can be sufficiently secured, so that productivity can be improved.

  Next, the vehicle rear structure according to the second embodiment will be described. FIG. 3 is a schematic cross-sectional view showing the configuration around the fuel tank disposed at the rear of the vehicle. The same reference numerals are given to the same parts as those in the first embodiment. In the vehicle rear structure 10 </ b> A of the present embodiment, an example in which the secondary battery (second electric system unit) 24 is disposed on the upper portions of the rear cross members 15 and 16 is shown. The illustration of the DC / DC converter (first electric system unit) 25 is omitted.

  In the secondary battery 24 in this embodiment, the front end portion 31 of the battery case 30 is installed on the cross-sectional area of the rear cross member 15, and the rear end portion 32 is installed on the cross-sectional area of the rear cross member 16. As shown in the schematic plan view of FIG. 4, the secondary battery 24 is fixed to the vehicle body at two locations, a front end portion 31 and a rear end portion 32 of the battery case 30.

  FIG. 5 is a schematic perspective view showing a portion where the secondary battery 24 is attached, and shows a structure on the vehicle body side from which the rear floor 22 is removed. A front end mounting bracket 41 is installed on the rear cross member 15 at a position where the front end portion 31 of the battery case 30 is mounted. The rear cross member 16 is provided with a rear end mounting bracket 51 at a position where the rear end portion 32 of the battery case 30 is mounted.

  As shown in the enlarged perspective view of FIG. 6, the front end mounting bracket 41 has a fixing nut 43 attached to the bracket body 42 by welding. Both end portions 42a of the bracket main body 42 are bent into an L shape, and are fixed to the inner wall of the rear cross member 15 by welding. As shown in the enlarged perspective view of FIG. 7, the rear end mounting bracket 51 has a stud bolt 53 for fixing and positioning attached to the bracket body 52 by welding. Both end portions 52a of the bracket body 52 are bent into an L shape and are fixed to the inner wall of the rear cross member 16 by welding.

  The secondary battery 24 is carried into the vehicle body from the back door opening (not shown) at the rear of the vehicle and attached. FIG. 8 is a partially enlarged view of FIG. 3, and is a side view for explaining a procedure for attaching the battery case 30 and the rear floor 22. When mounting the secondary battery 24, the rear end mounting hole 32a (first mounting hole) provided in the rear end portion 32 of the battery case 30 and the stud bolt 53 of the rear end mounting bracket 51 are fitted, The battery case 30 is placed on the rear floor 22. Since the stud bolt 53 of the rear end mounting bracket 51 functions as a positioning bolt, the battery case 30 is mounted on the rear floor 22 while the rear end mounting hole 32a of the battery case 30 and the stud bolt 53 are fitted. As a result, the secondary battery 24 is positioned at a predetermined mounting position. In this state, the rear end portion 32 of the battery case 30 is screwed and fixed with a nut 54. On the other hand, the front end attachment hole 31a (second attachment hole) provided in the front end portion 31 of the battery case 30 is formed to have a larger diameter than the rear end attachment hole 32a. By mounting on the front end 22, the front end mounting hole 31 a is placed at a position substantially coincident with the fixing nut 43 of the front end mounting bracket 41. Accordingly, the front end mounting hole 31a and the fixing nut 43 need not be positioned on the front side of the battery case 30, and the battery case 30 in which the secondary battery 24 is accommodated by fixing the front end portion 31 of the battery case 30 with the bolts 44 is fixed. 30 can be mounted on the rear floor 22.

  According to the vehicle rear structure 10A configured as described above, the front and rear of the secondary battery 24 are fixed on the cross-sectional areas of the rear cross members 15 and 16, so that the vehicle body rigidity and the battery can be reduced with a simple configuration. The attachment rigidity can be improved as compared with the first embodiment.

  Further, the rear end mounting hole 32a of the battery case 30 is fitted with the stud bolt 53 and fixed by the nut 54, and the front end mounting hole 31a is fixed by the bolt 44 at the position of the fixing nut 43. 24 can be attached only by observing only the fitting between the rear end attachment hole 32a of the battery case 30 and the stud bolt 53, and the number of assembling steps can be reduced.

  Incidentally, when a stud bolt is installed instead of the fixing nut 43, not only the rear end mounting hole 32a of the battery case 30 and the stud bolt 53 but also the front end mounting hole 31a and the stud bolt are fitted. Since it has to be closely watched, the installation work takes time and effort. Further, when a fixing nut is installed at the position of the stud bolt 53, it takes time to position the front end and the rear end of the battery case 30. Furthermore, when the arrangement of the fixing nut 43 and the stud bolt 53 is reversed, the worker must perform positioning with the stud bolt on the back side when viewed from the back door opening at the rear of the vehicle, so that the work efficiency is poor. Therefore, the installation work takes time and effort.

  Therefore, as in this embodiment, the rear end mounting hole 32a of the battery case 30 and the stud bolt 53 are fitted and fixed with the nut 54, and the front end mounting hole 31a is fixed with the bolt 44 at the position of the fixing nut 43. By adopting such a structure, it is possible to reduce the number of assembling steps because the mounting work does not take time and effort and the work efficiency is improved. In addition, the attachment structure of the fixing nut 43 and the stud bolt 53 is not limited to the example of FIG. 6, FIG. 7, The various attachment structure used normally can be applied. Further, the number of fixing nuts 43 and stud bolts 53 may be further increased.

  Next, the connection structure of the secondary battery harness will be described.

  FIG. 9 is a schematic bottom view of FIG. Here, in order to make the structure easy to understand, the rear suspension members 17 and 18 (see FIG. 2) are omitted. FIG. 10 is a schematic cross-sectional view corresponding to the line AA in FIG.

  As shown in FIG. 9, the rear cross members 15 and 16 are connected by tank brackets 61 and 62, and two secondary battery harnesses for positive electrode and negative electrode connected to the secondary battery 24 ( The harness 71 is taken out from the space of the rear floor 22 surrounded by the rear cross members 15 and 16, the rear side member 11 and the tank bracket 62 to the lower part of the vehicle. Thus, when it comprises so that the secondary battery harness 71 may be taken out from the clearance gap between small structures, the electrical safety at the time of the impact by a rear collision can be improved further.

  Further, in the secondary battery 24 in the present embodiment, as shown in FIG. 10, a power supply extraction portion 30 a provided at the lower portion of the battery case 30, a harness extraction portion 81 for extracting the secondary battery harness 71 from the vehicle lower portion, Are arranged at the same position. Here, the structure of the connection portion between the battery case 30 and the secondary battery harness 71 will be described with reference to FIG. 11 which is a partially enlarged view of FIG.

  A power supply extraction recess 30 b is formed in the lower part of the battery case 30, and a power supply extraction unit 30 a serving as a power supply terminal of the secondary battery 24 is provided inside the battery case 30. On the other hand, the rear floor 22 is formed with a harness extraction portion 81 directly below the power supply extraction recess 30b. When the battery case 30 is fixed on the rear floor 22, the power supply extraction portion 30a and the harness extraction portion 81 are almost planar. Configured to match. Further, a sealing material 82 is provided between the power supply recess 30b and the harness extraction portion 81 so as to cover the periphery of the power supply recess 30b and shields the outside from the room.

  Further, the harness connector 71a attached to the end of the secondary battery harness 71 and the power supply extraction portion 30a provided in the power supply extraction recess 30b are fitted to each other so as to obtain electrical conduction. ing.

  According to the connection structure of the secondary battery harness as described above, the power supply extraction portion 30a and the harness extraction portion 81 are placed at the same position and the periphery thereof is shielded by the sealing material 82. Without providing a grommet on the rear floor 22 to pass through, indoor watertightness can be ensured and the number of assembling steps can be reduced. Further, since the secondary battery 24 and the secondary battery harness 71 can be connected only by inserting the harness connector 71a into the harness take-out part 81 and fitting it with the power take-out part 30a, the secondary battery is connected to the rear floor 22 through the grommet. The secondary battery 24 and the secondary battery harness 71 can be easily connected to each other while ensuring water tightness as compared with the conventional method in which the harness 71 is passed through.

  In each of the above-described embodiments, an example in which the vehicle rear structure according to the present invention is applied to a fuel cell vehicle has been described. However, the present invention is not limited to a fuel cell vehicle. The present invention can be applied to various vehicles generally equipped with a battery such as a hybrid vehicle combined with a gasoline engine.

FIG. 3 is a schematic cross-sectional view showing a configuration around a fuel tank arranged at the rear of the vehicle (Example 1). The schematic bottom view of FIG. FIG. 5 is a schematic cross-sectional view showing a configuration around a fuel tank arranged at the rear of the vehicle (Example 2). FIG. 4 is a schematic bottom view of FIG. 3. The schematic perspective view which shows the attachment part of a secondary battery. The expansion perspective view of the attachment bracket for front ends. The expansion perspective view of the attachment bracket for rear ends. The elements on larger scale of FIG. FIG. 4 is a schematic bottom view of FIG. 3. FIG. 10 is a schematic cross-sectional view corresponding to the line AA in FIG. The elements on larger scale of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Vehicle rear part structure 11,12 ... Rear side member 13,14 ... Extension member 15,16 ... Rear cross member 17,18 ... Rear suspension member 19 ... Fuel tank 20 ... Tank frame 21 ... Front floor 22 ... Rear floor 23 ... Rear seat 23a ... Rear seat cushion 23b ... Hook part 24 ... Secondary battery 25 ... Converter 26 ... Converter harness 27 ... Battery unit cover 27a ... Upper end part of battery unit cover 27b ... Lower end part of battery unit cover 27c ... Vertical vertical surface 28 ... Luggage board 28a ... Luggage board front end 29 ... Mounting bolt 30 ... Battery case

Claims (6)

In the vehicle rear structure formed by arranging an electric system unit at the rear of the vehicle,
An extension part is provided at the rear part of the rear side member, a rear cross member is arranged on each of the rear suspension member on the vehicle front side and rear upper side, and the electric system unit is fixed on the rear cross member,
The front end portion of the electric system unit is fixed to the upper portion of the rear cross member on the front side, and the rear end portion of the electric system unit is fixed to the upper portion of the rear cross member on the rear side ,
The rear suspension member extends in the vehicle width direction and is arranged at the front and rear,
The rear suspension members are connected by a connecting portion extending in the front-rear direction,
The vehicle rear portion structure characterized in that the connecting portion connects a portion of the rear suspension member that is located on the inner side in the vehicle width direction and on the lower side than the rear side member with respect to the attachment portion with the rear side member . At least two first mounting holes are provided at the rear end portion of the electric system unit, and at the front end portions, second mounting holes having a diameter larger than the first mounting hole are provided at at least two locations,
Installing at least two stud bolts on the rear rear cross member at the rear of the vehicle, and installing at least two nuts on the front rear cross member;
The first mounting hole of the electric system unit is fitted with the stud bolt installed on the rear rear cross member and fixed with a nut, and the second mounting hole of the electric system unit is installed on the front rear cross member. The vehicle rear structure according to claim 1, wherein the vehicle rear structure is fixed by a bolt at the position of the nut. The vehicle rear part structure according to claim 1 or 2 , wherein a harness attached to the electric system unit is taken out from a floor surrounded by the rear cross member and the rear side member to a lower part of the vehicle. The power supply taking part provided in the lower part of the electric system unit and the harness taking out part for taking out the harness from the lower part of the vehicle are in the same position, and the periphery of the power supply taking out part and the harness taking out part is shielded by a sealing material. 4. The vehicle rear structure according to claim 3 , wherein A second electrical system unit is provided separately from the electrical system unit,
A rear seat is arranged on the vehicle front side of the electric system unit, the second electric system unit is installed along the rear surface of the rear seat, and a cover vertical surface is floored at the rear of the second electric system unit when installed. It becomes vertical with respect to, and any of claims 1 to 4, characterized in that a battery cover having a shape such that a space is formed between the second electrical system unit back and the cover longitudinal plane The vehicle rear structure according to claim 1. A luggage board is provided on an upper portion of the electric system unit, a vehicle front side of the luggage board is fixed to the electric system unit, an upper end portion of the battery cover is engaged with the rear seat, and a lower end portion is disposed on the electric system unit. The vehicle rear portion structure according to claim 5 , wherein the vehicle rear portion structure is fixed below a front end of the luggage board.

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