JP6078013B2 - Vehicle rear structure - Google Patents

Description

  The present invention relates to a vehicle rear structure in which a spare tire storage portion for storing a spare tire is recessed in a rear floor panel.

  Conventionally, in a vehicle such as a passenger car, when a low-voltage device such as an optional electrical component for a vehicle by a user is arranged in the vehicle, a battery (hereinafter referred to as a main battery) arranged in the engine compartment or on the floor panel in advance. In some cases, a low voltage battery may be newly arranged at any position on the floor panel. In this case, since the low-voltage battery is a DC voltage, an inverter that converts the DC voltage of the low-voltage battery into an AC voltage and can be used in the low-voltage device is also used to supply power to a low-voltage device that functions with an AC voltage. Must be placed.

  In particular, in the case of a hybrid vehicle equipped with two power mechanisms different in engine and motor, and the vehicle form is SUV (Sport Utility Vehicle) or minivan, the existing battery such as a motor drive battery is on the front floor panel or the center floor panel. Since it is difficult to arrange the low voltage battery on the two floor panels, the low voltage battery is arranged on the rear floor panel (for example, Patent Document 1, Patent Reference 2 and Patent Reference 3). Further, the inverter is arranged on the rear floor panel according to the arrangement state of a battery group such as an existing battery or a low voltage battery (for example, see Patent Document 1), or under the seat portion of the front seat and the front floor in the vehicle interior. It is arranged in a space secured between the panels.

  In this specification, the front floor panel means the floor panel portion from the lower end of the dash panel to the rear seat foot, the center floor panel means the floor panel portion under the rear seat, and the rear floor panel means the rear seat rear. It shall mean the floor panel part.

Japanese Patent Laid-Open No. 2004-148852 JP 2013-169849 A International Publication No. 2011/148725

  However, in the vehicle electric equipment fixing structure (Patent Document 1) in which both the inverter and the battery are arranged on the rear floor panel, the inverter is fixed in a recess formed in the rear part of the rear floor (rear floor panel). It is mounted on the first bracket, and the battery is mounted on the second bracket fixed to the upper part of the first bracket and fixed to the left and right wheel houses. Although it can be increased, it is difficult to avoid stress concentration due to resonance vibration of the rear floor. In addition, since the battery is stacked on the inverter, there is a difficulty in obstructing the rack space in the passenger compartment at the rear of the vehicle. Furthermore, the first bracket is fixed to the recess by screw fastening, and the second bracket is fixed to the first bracket and the left and right wheel houses by screw fastening. There was a risk of lowering.

  Further, in a vehicle rear structure in which a battery is accommodated in a battery tray having a side surface fixed to the wheel house and a bottom surface fixed to the rear floor panel (Patent Document 2), it is located beside one wheel house on the rear floor panel. Since the battery is arranged, there is a problem that the rack space in the vehicle interior at the rear of the vehicle is obstructed and the symmetrical rigidity at the rear of the vehicle cannot be secured.

  Further, the rear floor panel is provided with a spare tire house formed to be recessed below the vehicle, and a charging component mounting structure at the rear of the vehicle in which a charger is simply attached to the bottom of the spare tire house (Patent Document 3). Thus, it was difficult to avoid stress concentration due to resonance vibration of the rear floor.

  In addition, when the inverter is disposed in a space secured between the front seat under the seat of the front seat in the vehicle interior, acoustic-related electrical components such as a surround system can be disposed in the vehicle interior. There is a difficulty that becomes difficult, and since the inverter arranged in the space can be seen in the passenger compartment, there is a difficulty that it is necessary to provide a good appearance cover to make the inverter invisible in order to improve the appearance, Furthermore, when an AC 100V outlet is provided at the rear of the vehicle so that it can be used as a power source in the event of a power failure such as in a house, etc., the outlet and an inverter disposed under the seat of the front seat are electrically connected. Wiring work is complicated by the length of the wire harness for connection, and the manufacturing cost is reduced. There is a drawback to rise.

  The present invention has been made to solve such a conventional problem, and even if a low-voltage battery and an inverter are incorporated in a spare tire storage portion recessed in the rear floor panel, a rack space in the vehicle interior at the rear of the vehicle is provided. Without impairing the performance of the rear floor panel in which the spare tire storage portion is recessed, and reducing the indoor noise caused by the resonance vibration of the rear floor panel in which the spare tire storage portion is recessed. An object of the present invention is to provide a vehicle rear structure that can be used.

The vehicle rear portion structure according to the first aspect of the present invention that achieves the above-described object includes a bottom portion that is recessed in the rear floor panel toward the vehicle lower side and on which a spare tire is placed, and a vertical portion that is erected from the bottom portion. In the spare tire storage part that is integrally formed with the wall part, a low-voltage battery that supplies power to the low-voltage device and an inverter that converts the DC voltage of the low-voltage battery into an AC voltage and can be used in the low-voltage device Is a vehicle rear structure in which a battery attachment reinforcement to which a low voltage battery is attached and an inverter attachment bracket to which an inverter is attached. In this specification, “recessed” means providing in a recessed state. “Standing” means providing in a standing state.
The bracket for mounting the inverter has a space between the vertical wall portion of the spare tire storage portion, and has a first fixing portion on one side and a second fixing portion on the other side across the mounting portion to which the inverter is mounted. The first fixing part is fixed to the rear floor panel that is located in the front direction of the vehicle longitudinal direction, and the second fixing part is located in the rear direction of the vehicle longitudinal direction. It is fixed to the bottom of the spare tire storage section to be performed.
The battery mounting reinforcement is formed in an elongated shape, the longitudinal direction of the battery mounting reinforcement is arranged along the vehicle width direction at the bottom of the spare tire storage unit, and the vehicle mounting direction is rearward with respect to the inverter mounting bracket. It is what is being fixed to the bottom part so that it may be arrange | positioned.

  According to such a vehicle rear structure as the first aspect, the inverter mounting bracket is arranged such that the first fixing portion and the second fixing portion are along the vehicle front-rear direction, and the battery mounting reinforcement is Since it is arranged along the vehicle width direction of the vehicle, the rigidity of the spare tire storage portion in the vehicle front-rear direction and the vehicle vehicle width direction can be enhanced. Even if an inverter is installed, it is possible to improve the durability performance of the rear floor panel in which the spare tire storage part is recessed by suppressing the displacement of the spare tire storage part in the vehicle vertical direction. Since there is a space between the vertical wall portion of the tire storage portion, a dynamic damper is configured with an inverter to be attached. Therefore, by controlling the resonance frequency of the rear floor panel in which the spare tire storage portion is recessed by this dynamic damper, it is possible to avoid stress concentration caused by the resonance vibration of the rear floor panel and to reduce indoor noise. Can be made.

  In the vehicle rear structure according to the second aspect of the present invention, the inverter mounting bracket is located at a position outside the range in which the inverter is mounted on the side of the mounting portion extending to the second fixed portion. The spare tire storage portion is bent into a generally U shape so as to keep a space in the vertical wall portion and the bottom portion of the spare tire storage portion, and the second fixing portion is substantially in the vehicle width direction and the vehicle front-rear direction of the bottom portion. It is fixed at the center position. In this specification, “extending” means providing in one direction.

  According to the vehicle rear portion structure as the second aspect as described above, the dynamic damper can be provided with the elastic function even at the portion of the inverter mounting bracket that is bent into a substantially square shape. The vibration damping function can be enhanced, and further, the second fixing portion of the inverter mounting bracket is fixed at substantially the center position in the vehicle width direction and the vehicle front-rear direction at the bottom of the spare tire storage portion. The displacement of the spare tire storage portion in the vehicle vertical direction can be effectively suppressed.

  According to a third aspect of the present invention, in the vehicle rear portion structure according to the first aspect or the second aspect, when a cross member is provided on a rear floor panel positioned in the front direction of the vehicle front-rear direction of the spare tire storage portion. The first fixing portion is fixed to the cross member.

  According to such a vehicle rear portion structure as the third aspect, it is effective when the rigidity of the rear floor panel is inferior to the rigidity of the cross member, and the displacement of the spare tire storage portion in the vehicle vertical direction is a reinforcement member. Can be suppressed by members.

  According to a fourth aspect of the present invention, in the vehicle rear portion structure according to any one of the first to third aspects, the spare tire storage portion is a substantially central portion of the rear floor panel in the vehicle vehicle width direction. Is recessed.

  According to such a vehicle rear portion structure as the fourth aspect, even if the low-voltage battery and the inverter are arranged in the spare tire housing portion, the spare tire housing portion is substantially in the vehicle width direction of the rear floor panel. Since it is recessed in the central portion, it is possible to ensure symmetrical rigidity in the rear part of the vehicle.

  According to the vehicle rear structure of the present invention, even if a low-voltage battery and an inverter are incorporated in a spare tire storage portion recessed in the rear floor panel, the spare tire storage portion is not hindered by the rack space in the vehicle interior at the rear of the vehicle. In addition to preventing a decrease in the durability performance of the rear floor panel with the recessed portion, it is possible to avoid stress concentration due to resonance vibration of the rear floor panel with the spare tire storage portion being recessed, and to reduce indoor noise. Will be able to.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows preferable embodiment in the vehicle rear part structure of this invention, (A) is a top view of the state in which the low voltage battery and the inverter were integrated in the spare-tire storage part of a rear floor panel, (B) is a figure of (A). It is sectional drawing of an AA cross section. It is a top view which shows the whole floor panel to which the vehicle rear part structure of this invention is applied. It is a disassembled perspective view of the vehicle rear part structure of this invention shown by FIG. 1 (A). (A) is a graph showing a vibration level waveform for a specific resonance frequency of the rear floor panel, (B) is a vibration level waveform for a set frequency for suppressing the resonance vibration of the rear floor panel of the inverter mounting bracket to which the inverter is mounted. (C) is a graph showing the waveform of the vibration level when the resonance vibration of the rear floor panel is damped by the inverter mounting bracket to which the inverter is mounted. (A), (B), (C) is a top view which shows each different embodiment of the state in which the low voltage battery and the inverter were integrated in the spare-tire storage part of a rear floor panel. 2A and 2B are explanatory views showing states before and after deformation due to vibration of a spare tire storage portion of the rear floor panel, in which FIG. 1A is a spare tire storage portion in the vehicle rear structure of FIG. 1, and FIG. A spare tire storage part, (C) is a spare tire storage part in the vehicle rear structure of FIG. 5 (B), and (D) is a spare tire storage part in the vehicle rear structure of FIG. 5 (C). (A) is the fragmentary perspective view of the BB cross section of FIG. 5 (A), (B) is the fragmentary perspective view of CC cross section of FIG. 1 (A). 7A is an explanatory view showing a state before and after deformation of the spare tire storage portion, battery mounting reinforcement and inverter mounting bracket in the spare tire storage portion of the rear floor panel, and FIG. 7A corresponds to FIG. FIG. 7B is a diagram corresponding to FIG. It is a bottom view which shows the state which looked at the spare tire storage part of the rear floor panel from the bottom. FIG. 10 is a stress contour diagram showing a deformation state due to vibration in the spare tire storage portion shown in FIG. 9, where (A) is a diagram corresponding to FIG. 1 (A), (B) is a diagram corresponding to FIG. ) Is a diagram corresponding to FIG. 5B, and FIG. 5D is a diagram corresponding to FIG. It is a graph which shows the life ratio derived | led-out from FIG. 10 (A), (B), (C), (D).

  Hereinafter, embodiments for implementing the vehicle rear structure of the present invention will be described with reference to the drawings. In each of the drawings used in the embodiment for carrying out the present invention, the direction is indicated by an arrow, and this indicates the direction as seen from the occupant seated in the driver's seat. Arrow UP indicates the vehicle upward direction, arrow Fr indicates the vehicle forward direction, arrow RH indicates the vehicle right direction, and arrow LH indicates the vehicle left direction.

  As shown in FIGS. 1A, 1B, 2 and 3, the vehicle rear structure according to the present invention is recessed in the rear floor panel 1 toward the vehicle lower side, and a spare tire (not shown) is mounted. A low-voltage battery 3 for supplying power to a low-voltage device and a low voltage in a spare tire storage unit 2 in which a bottom 2a to be placed and a vertical wall 2b erected from the bottom 2a are integrally formed An inverter 4 that converts the DC voltage of the battery 3 into an AC voltage and can be used in a low-voltage device is disposed. Moreover, it has a battery attachment reinforcement 5 to which the low voltage battery 3 is attached, and an inverter attachment bracket 6 to which the inverter 4 is attached. In addition, description of the inverter 4 is abbreviate | omitted in FIG. 1 (A), and description of the low voltage battery 3 and the inverter 4 is abbreviate | omitted in FIG. 1 (B).

  The spare tire storage portion 2 has a space surrounded by the bottom portion 2a and the vertical wall portion 2b from the front side in the vehicle front-rear direction, both sides in the vehicle vehicle width direction, and the lower side in the vehicle vertical direction. A flange portion 2c extends from the upper surface in the horizontal direction toward the outside. The spare tire storage portion 2 formed in this way includes a first rear cross member 7 located on the front side in the vehicle longitudinal direction, a second rear cross member 8 located on the rear side in the vehicle longitudinal direction, and the vehicle width direction. Are joined by spot welding or the like so as to surround the right and left side members 9A and 9B located on both sides of the left and right sides. The first rear cross member 7, the second rear cross member 8, and the right and left side members 9A and 9B are reinforcing members for the rear floor panel 1.

  The inverter mounting bracket 6 has a space between the vertical wall portion 2b of the spare tire storage portion 2, and the first fixing portion 6b on one side and the other side on the other side of the mounting portion 6a to which the inverter 4 is attached. A second fixing portion 6c is provided. The inverter mounting bracket 6 has the mounting portion 6a as a position reference, and the first fixing portion 6b is positioned on the flange portion 2c of the rear floor panel 1 that is positioned in the forward direction in the vehicle front-rear direction. The second fixing portion 6c is fixed by screwing with a screwing member such as a screw to the bottom 2a of the spare tire storage unit 2 which is fixed by screwing with a joint member and is located in the rearward direction of the vehicle front-rear direction. Has been.

  In order to attach the inverter 4 to the inverter mounting bracket 6 having such a structure, screwing fastening with a screwing member such as a screw or fixing means using an elastic member band such as rubber is used.

  The battery mounting reinforcement 5 is formed in a long shape. The battery mounting reinforcement 5 formed in this way is arranged on the bottom 2a of the spare tire storage portion 2 along the vehicle width direction of the spare tire storage portion 2 and in the vehicle longitudinal direction with respect to the inverter mounting bracket 6. It is fixed to the bottom 2a so as to be arranged in the rearward direction. That is, the inverter mounting bracket 6 is disposed along the vehicle longitudinal direction, and the battery mounting reinforcement 5 is disposed along the vehicle width direction. In this case, the low voltage battery 3 attached to the battery attachment reinforcement 5 is attached to any one of the vertical wall surfaces 2b on the rear side in the vehicle front-rear direction of the spare tire storage unit 2 on the two vertical wall surfaces 2b. The inverter 4 is arranged along the vertical wall surface 2b located on the front side of the spare tire storage unit 2 in the vehicle front-rear direction.

  In order to arrange the low voltage battery in the spare tire storage portion 2 using the battery mounting reinforcement 5 having such a structure, the battery mounting reinforcement 5 is screwed by a screwing member such as a screw. The battery tray 11 that is fixed by fastening and mounts the low-voltage battery 3, and the low-voltage battery 3 mounted on the battery tray 11 is screwed to the battery mounting reinforcement 5 and the rear floor panel 1 by screwing members such as screws, respectively. A battery fastening band 12 fixed by fastening is used. In addition, the arrangement | positioning method which arrange | positions the low voltage battery 3 in the spare tire storage part 2 using the battery attachment reinforcement 5 is not restricted to this, A low voltage battery using the battery attachment reinforcement 5 is used. Any arrangement method may be used as long as 3 can be arranged in the spare tire storage unit 2.

  In the vehicle rear structure of the present invention configured as described above, the inverter mounting bracket 6 has the first fixing portion 6b and the second fixing portion 6c so as to increase the rigidity of the spare tire storage portion 2 in the vehicle front-rear direction. Since the battery mounting reinforcement 5 is arranged along the vehicle width direction so as to increase the rigidity of the spare tire storage portion 2 in the vehicle width direction of the vehicle, the spare tire is arranged along the vehicle longitudinal direction. The rigidity of the storage unit 2 in the vehicle front-rear direction and the vehicle vehicle width direction can be enhanced. Therefore, even if the low-voltage battery 3 and the inverter 4 which are heavy objects are mounted in the spare tire storage unit 2, the spare tire storage unit 2 is recessed by suppressing the displacement of the spare tire storage unit 2 in the vehicle vertical direction. Further, the durability performance of the rear floor panel 1 can be improved.

  Furthermore, since the inverter mounting bracket 6 has a space between it and the vertical wall portion 2b of the spare tire storage portion 2, it constitutes a dynamic damper together with the inverter 4 to be mounted. Therefore, the resonance frequency of the rear floor panel 1 in which the spare tire storage portion 2 is recessed can be controlled by this dynamic damper. That is, as shown in FIG. 4A, the vibration level of the rear floor panel 1 provided with the spare tire storage unit 2 is such that the waveform WP1 of the rear floor panel 1 has an upward peak P1 in the frequency range of interest Z (FIG. 4 ( C))), the setting frequency formed by the dynamic damper waveform WP2 is close to the resonance frequency of the rear floor panel 1 as shown in FIG. The mass of the inverter 4 and the inverter mounting bracket 6 constituting the dynamic damper, the spring constant or the damping coefficient of the inverter mounting bracket 6 are adjusted.

  When the characteristics of the dynamic damper are set in this way, as shown in FIG. 4C, the vibration level waveform of the rear floor panel 1 has a downward peak P2 at the resonance frequency formed in the frequency range of interest Z. A resonance waveform having a relatively small upward peak that is substantially uniform on the low frequency side and the high frequency side across the resonance frequency is formed. These two resonance waveforms can be set to a level lower than the target vibration level P that can eliminate the harmful effects caused by the resonance vibration. Thereby, the resonance vibration of the rear floor panel 1 can be effectively reduced based on the set frequency of the dynamic damper.

  That is, by controlling the resonance frequency of the rear floor panel 1 in which the spare tire storage portion 2 is recessed by the dynamic damper, stress concentration which is a harmful effect due to the resonance vibration of the rear floor panel can be avoided, and Noise can be reduced.

  In the vehicle rear structure according to the present invention, the inverter 4 is fixed in the spare tire storage portion 2 by the inverter mounting bracket 6, and the battery 3 is fixed in the spare tire storage portion 2 by the battery mounting reinforcement 5. Therefore, since the screw fastening accuracy does not decrease, the component assembly accuracy does not decrease.

  Further, in the vehicle rear structure of the present invention, the inverter 4 can be disposed in the spare tire storage portion 2 of the rear floor panel 1, so that the AC 100V outlet provided at the rear portion of the vehicle and the inverter 4 are electrically connected. Since the wire harness for connection is shortened and the wiring work is simplified, an increase in manufacturing cost can be suppressed.

  Further, in the vehicle rear structure of the present invention, the low voltage battery 3 and the inverter 4 are stored in the spare tire storage portion 2 of the rear floor panel 1, which obstructs the rack space in the vehicle interior at the rear of the vehicle. There is no.

  Further, in the vehicle rear portion structure of the present invention, the inverter mounting bracket 6 has a spare tire storage portion at a position outside the range where the inverter 6 is mounted on the extending side of the mounting portion 6a to the second fixing portion 6c. The second fixing portion 6c is fixed at substantially the center position in the vehicle width direction and the vehicle front-rear direction of the bottom portion 2a, respectively, along the vertical wall portion 2b and the bottom portion 2a. It may be.

  By adopting such a structure, it is possible to provide the elastic function of the dynamic damper even at the portion of the inverter mounting bracket 6 bent into a substantially square shape, so that the vibration damping function of the dynamic damper is enhanced. Can do. Further, since the second fixing portion 6c of the inverter mounting bracket 6 is fixed at substantially the center position in the vehicle width direction and the vehicle longitudinal direction of the bottom portion 2a of the spare tire storage portion 2, the spare tire storage portion The displacement of the vehicle 2 in the vertical direction can be effectively suppressed.

  In the vehicle rear structure of the present invention, when the first cross member 7 is provided on the rear floor panel 1 positioned in the front direction of the vehicle front-rear direction of the spare tire storage portion 2, the first fixing portion 6b is provided. May be fixed to the cross member 7.

  Such a structure is effective when the rigidity of the flange portion 2c of the rear floor panel 1 is inferior to the rigidity of the first cross member 7, and the displacement of the spare tire storage portion 2 in the vehicle vertical direction is set by a reinforcing member. It can be suppressed by a certain first cross member 7.

  In the vehicle rear portion structure of the present invention, the spare tire storage portion 2 is preferably recessed at a substantially central portion of the rear floor panel 1 in the vehicle width direction.

  With this structure, even when the low-voltage battery 3 and the inverter 4 are arranged in the spare tire storage unit 2, the spare tire storage unit 2 is substantially in the vehicle width direction of the rear floor panel 1. Since it is recessed in the central portion, it is possible to ensure symmetrical rigidity in the rear part of the vehicle.

  Next, the optimal arrangement structure of the low voltage battery and the inverter by the vehicle rear structure according to the present invention will be described in comparison with several arrangement examples of the low voltage battery and the inverter. For the structural analysis for comparison, a personal computer installed with a general-purpose analysis program by FEM (finite element method) was used.

  5A, 5B, and 5C show examples of arrangement of the low-voltage battery and the inverter to be compared with the vehicle rear structure of the present invention. Since the rear floor panel shown in FIGS. 5A, 5B, and 5C is the same as the vehicle rear structure of the present invention, the constituent members are given the same reference numerals as the vehicle rear structure of the present invention. Further, since the battery and the battery mounting reinforcement are the same, the same reference numerals as those of the vehicle rear structure of the present invention are given. 5 (A), (B), and (C), the battery 3 uses a battery mounting reinforcement 5 and is installed in the spare tire storage unit 2 by the same mounting means as the vehicle rear structure of the present invention. Is arranged.

  In the first vehicle rear structure which is a comparison target shown in FIG. 5A, the inverter mounting bracket 61 to which the inverter 4 is mounted is disposed in the front direction of the vehicle longitudinal direction with respect to the battery mounting reinforcement 5. The first fixing portion 61b is fixed to the front portion in the vehicle front-rear direction on the bottom portion 2a of the spare tire storage portion 2 with the mounting portion 61a to which the inverter 4 is attached as a position reference, and the second fixing portion 61c. Is fixed to the rear portion of the bottom portion 2a of the spare tire storage portion 2 in the rearward direction of the vehicle. In this case, the inverter 4 is arranged at the front position in the vehicle front-rear direction at the bottom 2 a of the spare tire storage unit 2.

  In the second vehicle rear portion structure to be compared shown in FIG. 5B, the inverter mounting bracket 62 to which the inverter 4 is mounted is disposed in the front direction of the vehicle longitudinal direction with respect to the battery mounting reinforcement 5. The first fixing portion 62b is fixed to the right portion in the vehicle width direction of the bottom portion 2a of the spare tire storage portion 2 with the mounting portion 62a to which the inverter 4 is attached as a position reference. 62c is fixed to the left portion of the bottom portion 2a of the spare tire storage portion 2 in the vehicle width direction. In this case, the inverter 4 is arranged at a position in the right direction in the vehicle width direction in the bottom 2a of the spare tire storage unit 2.

  In the third vehicle rear structure, which is a comparison object shown in FIG. 5C, the inverter mounting bracket 63 to which the inverter 4 is mounted is disposed in the front direction of the vehicle longitudinal direction with respect to the battery mounting reinforcement 5. The first fixing portion 63b is fixed to the right side member 9A, which is positioned rightward in the vehicle width direction, with the mounting portion 63a to which the inverter 4 is attached as a position reference, and the second fixing portion 63c. Is fixed at a substantially central position in the vehicle width direction of the bottom 2a of the spare tire storage unit 2. In this case, the inverter 4 is arranged at a position in the right direction in the vehicle width direction in the bottom 2a of the spare tire storage unit 2.

  First, the sectional deformation of the vehicle rear structure of the present invention at the position of line L1 shown in FIG. 1A, the sectional deformation of the first vehicle rear structure at the position of line L2 shown in FIG. 5A, and the second vehicle. The cross-sectional deformation of the rear structure at the position of line L3 shown in FIG. 5B was compared with the cross-sectional deformation of the third vehicle rear structure at the position of line L4 shown in FIG. 5C. That is, the rigidity of the spare tire storage unit 2 in the vehicle width direction was compared. Specifically, the thrust load from the tire was set to a predetermined value, and the amount by which the bottom 2a of the spare tire storage unit 2 was displaced from the reference value in the vehicle upward direction by the thrust load was detected.

  The analysis results show that the displacement M2 is 2.8 mm as shown in FIG. 6B in the first vehicle rear structure, and the displacement M3 is 2.8 mm as shown in FIG. 6C in the second vehicle rear structure. In the third vehicle rear structure, the displacement M4 is 2.6 mm as shown in FIG. 6D, whereas in the vehicle rear structure of the present invention, the displacement M1 is 2.2. It was 3 mm. Therefore, it is confirmed that the vehicle rear structure of the present invention has improved the rigidity of the spare tire storage unit 2 in the vehicle vehicle width direction compared to the first vehicle rear structure, the second vehicle rear structure, and the third vehicle rear structure. did it. In FIG. 6, the dotted line is before deformation, and the solid line is after deformation.

  Next, the cross-sectional deformation shown in FIG. 7B of the vehicle rear structure of the present invention was compared with the cross-sectional deformation shown in FIG. 7A of the first vehicle rear structure. That is, the rigidity of the spare tire storage portion 2 in the longitudinal direction of the vehicle was compared. Specifically, the thrust load from the tire was set to a predetermined value, and the amount by which the bottom 2a of the spare tire storage unit 2 was displaced from the reference value in the vehicle upward direction by the thrust load was detected. 7A is the position of the cross section BB ′ shown in FIG. 5A, and the cross section shown in FIG. 7B is the cross section A— shown in FIG. This is the position of A ′.

  As a result of the analysis, the displacement D1 shown in FIG. 8A which is the first vehicle rear structure is larger than the displacement D2 shown in FIG. 8B which is the vehicle rear structure of the present invention. Therefore, it was confirmed that the vehicle rear structure of the present invention has improved the rigidity of the spare tire storage unit 2 in the vehicle width direction of the first vehicle rear structure. In FIG. 8, the dotted line is before deformation and the solid line is after deformation. Further, since the second vehicle rear structure and the third vehicle rear structure are obviously not arranged in the direction in which the mounting directions of the inverter mounting brackets 62 and 63 are increased in the rigidity of the spare tire storage unit 2. Not subject to comparison.

  Next, the stress analysis in the range Ar of the bottom part 2a of the spare tire storage part 2 shown in FIG. 9 was performed. In this stress analysis, the thrust load from the tire was set to a predetermined value, and the stress generated in the range Ar of the bottom portion 2a of the spare tire storage unit 2 by the thrust load was detected. The range Ar is a place where the low voltage battery 3 is mounted in the spare tire storage unit 2. Further, as shown in FIG. 10, the place where the stress is generated is a painted portion with a plurality of points.

  As a result of the analysis, the vehicle rear structure of the present invention has a stress generation range as shown in FIG. 10A, the stress generation range of the first vehicle rear structure shown in FIG. 10B, and FIG. 10C. It was confirmed that the stress generation range of the second vehicle rear structure shown in FIG. 3 and the stress generation range of the third vehicle rear structure shown in FIG. Therefore, the vehicle rear portion structure of the present invention reduces the stress generated in the range Ar of the bottom portion 2a of the spare tire storage portion 2 from the first vehicle rear portion structure, the second vehicle rear portion structure, and the third vehicle rear portion structure. Therefore, as shown in FIG. 11, it has been found that the life of the rear floor panel 1 is improved.

  As can be seen from the three types of structural analysis described above, the vehicle rear structure of the present invention can be realized even if the low-voltage battery 3 and the inverter 4 are incorporated in the spare tire storage portion 2 recessed in the rear floor panel 1. The rear floor panel 1 in which the spare tire storage portion 2 is recessed is prevented from deteriorating without impeding the rack space in the vehicle interior at the rear of the vehicle, and the rear floor in which the spare tire storage portion 2 is recessed Stress concentration caused by resonance vibration of the panel 1 can be avoided, and indoor noise can be reduced.

  Although the present invention has been described with the specific embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and is known so far as long as the effects of the present invention are achieved. It goes without saying that any configuration can be adopted.

DESCRIPTION OF SYMBOLS 1 ... Rear floor panel 2 ... Spare tire storage part 2a ...... Bottom part 2b ... Vertical wall part 3 ... Low voltage battery 4 ... Inverter 5 ... Lean reinforcement for battery installation 6 ... Bracket for inverter installation 6a ... ... Attachment part 6b …… First fixing part 6c …… Second fixing part 7 …… First cross member

Claims (4)

Power is supplied to the low-voltage equipment in the spare tire storage part, which is recessed in the rear floor panel toward the lower side of the vehicle and in which the bottom part on which the spare tire is placed and the vertical wall part erected from the bottom part are integrally formed. A vehicle rear structure in which a low-voltage battery that supplies a low-voltage battery and an inverter that converts a direct-current voltage of the low-voltage battery into an alternating-current voltage and can be used in the low-voltage device,
A battery mounting reinforcement for mounting the low-voltage battery, and an inverter mounting bracket for mounting the inverter;
The inverter mounting bracket has a space between the vertical wall portion of the spare tire storage portion, a first fixing portion on one side and a second fixing portion on the other side across the mounting portion to which the inverter is attached. The first fixing part is fixed to the rear floor panel, which is positioned in the front direction of the vehicle longitudinal direction, with the mounting part as a position reference, and the second fixing part is It is fixed to the bottom of the spare tire storage that will be located in the rear direction of the vehicle,
The battery mounting reinforcement is formed in a long shape, and the longitudinal direction of the spare tire mounting portion is disposed along the vehicle width direction at the bottom of the spare tire storage portion, and the vehicle mounting front and rear are arranged with respect to the inverter mounting bracket. A vehicle rear portion structure fixed to the bottom portion so as to be arranged in a rearward direction.   The bracket for mounting the inverter is a space in the vertical wall portion and the bottom portion of the spare tire storage portion at a position outside the range where the inverter is mounted on the side where the mounting portion extends to the second fixed portion. The second fixing part is fixed at a substantially central position in each of the vehicle width direction and the vehicle front-rear direction of the bottom part. The vehicle rear structure according to claim 1.   In the case where a cross member is provided on the rear floor panel located in the front direction of the vehicle front-rear direction of the spare tire storage unit, the first fixing portion is fixed to the cross member. The vehicle rear part structure according to claim 1 or 2.   The vehicle rear portion according to any one of claims 1 to 3, wherein the spare tire storage portion is recessed in a substantially central portion of the rear floor panel in the vehicle width direction. Construction.

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