Abstract:
A vehicle equipment mounting structure that arranges a motor case, in which a rotary electric machine that drives a vehicle is housed, in an engine compartment, and that includes a PCU that controls the rotary electric machine, and an auxiliary battery that supplies electric power to the PCU. This structure includes a fixing portion that fixes the PCU onto the motor case, and a connecting portion that connects the auxiliary battery to a side member that absorbs an impact load by being crushed in a crushing direction. The connecting portion has a displaceable member that is displaceable in the crushing direction. The auxiliary battery is arranged on a vehicle front side of the PCU such that the PCU and the auxiliary battery partially overlap in the crushing direction. The auxiliary battery is arranged so as to be able to move past the PCU in response to an impact load.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a vehicle equipment mounting structure that arranges a motor case, in which a rotary electric machine that drives a vehicle is housed, in a compartment provided forward of a vehicle cabin, and that mounts a power control apparatus that controls the rotary electric machine, and an auxiliary battery that supplies electric power to a control portion of the power control apparatus. 
         [0003]    2. Description of Related Art 
         [0004]    Electric vehicles in which the vehicle is driven by driving force from a rotary electric machine such as a motor-generator, hybrid vehicles in which the vehicle is driven by a combination of a rotary electric machine and an engine that is an internal combustion engine, and fuel cell vehicles in which the vehicle is driven by electric power generated by a fuel cell, and the like are known. These kinds of vehicles are equipped with a power control apparatus that receives a supply of electric power from a main battery or a fuel cell, and has a step up converter and inverter and the like that control the electric power to a motor-generator (hereinafter, also referred to as “motor”). 
         [0005]    The power control apparatus is also referred to as a PCU (power control unit), and must be mounted in an engine compartment that is close to the motor-generator in order to handle the high voltage and high current. Therefore, in a hybrid vehicle in which the engine is started by the motor-generator, an auxiliary battery for starting the engine is arranged in the luggage compartment because it does not need to be arranged near the engine, as well as for reasons related to space in the engine compartment. In recent years, high-voltage equipment is being made smaller and smaller, so the auxiliary battery is now able to be arranged inside the engine compartment and near the power control apparatus. As a result, a cable that had to be brought around to the luggage compartment can be reduced, thereby enabling both weight and cost to be reduced. 
         [0006]    However, when the auxiliary battery is arranged near the power control apparatus, it is preferable to avoid interference between the auxiliary battery and power control apparatus in order to quickly and efficiently protect and rapidly discharge the power control apparatus when the vehicle is involved in a collision. Also, although there would be little harm from damage to the auxiliary battery because it is a relatively low voltage of only 12 volts, it is desirable to keep damage to the electric power apparatus that controls high voltage of several hundred volts to a minimum. 
         [0007]    Therefore, technology described in Japanese Patent Application Publication No. 2002-362254 (JP-A-2002-362254) has a detachable mechanism in which, when the vehicle is involved in a collision, a relay box moves upward and detaches from a vehicle body in response to a load transmitted from an auxiliary battery via a guide surface when the auxiliary battery moves to the rear as a result of a barrier (i.e., an obstacle) penetrating the vehicle. The battery moves smoothly toward the rear by this mechanism. Providing this kind of detachable structure for the relay box makes it possible to improve the impact absorption performance by preventing interference between vehicle equipment and other members that move by the impact of a collision. Japanese Patent Application Publication No. 2010-158991 (JP-A-2010-158991) describes an equipment mounting structure that mounts a front end of a power control apparatus in a position farther back toward the rear of the vehicle than a front end of a motor case, and that arranges an electric compressor on the vehicle rear side of the power control apparatus, in order to protect the power control apparatus itself when the vehicle is involved in a collision. 
         [0008]    With the structure described in JP-A-2002-362254 and JP-A-2010-158991, the auxiliary battery is able to be mounted using the space created in front of the motor case, by arranging the detachable structure and the power control apparatus in a location farther back on the motor case toward the rear of the vehicle. However, with a structure in which the auxiliary battery is arranged in front of the motor case, it is necessary to provide a detachable structure that safely moves the power control apparatus that is positioned to the vehicle rear of the auxiliary battery in order to protect and enable rapid discharge of the power control apparatus when the vehicle is involved in an collision, which leads to an increase in cost. 
       SUMMARY OF THE INVENTION 
       [0009]    The invention thus provides a vehicle equipment mounting structure that moves an auxiliary battery toward the rear past a power control apparatus, without the auxiliary battery that is arranged near the power control apparatus interfering with the power control apparatus when there is a collision. 
         [0010]    On aspect of the invention thus relates to a vehicle equipment mounting structure. This vehicle equipment mounting structure arranges a motor case, in which a rotary electric machine that drives a vehicle is housed, in a compartment provided forward of a vehicle cabin, and mounts a power control apparatus that controls the rotary electric machine, and an auxiliary battery that supplies electric power to a control portion of the power control apparatus. This vehicle equipment mounting structure has a fixing portion that fixes the power control apparatus onto the motor case, and a connecting portion that connects the auxiliary battery to a vehicle frame member that absorbs an impact load by being crushed in a crushing direction. The connecting portion includes a displaceable member that is displaceable in the crushing direction. The auxiliary battery is arranged on a vehicle front side of the power control apparatus such that the power control apparatus and the auxiliary battery partially overlap in the crushing direction, and the auxiliary battery is arranged so as to be able to move past the power control apparatus in response to the impact load. 
         [0011]    Also, in the vehicle equipment mounting structure according to this aspect of the invention, the connecting portion may connect the auxiliary battery to the vehicle frame structure such that a front end portion of the auxiliary battery is farther toward the vehicle front side than a front end portion of the power control apparatus is. With this kind of arrangement, the auxiliary battery will absorb the impact before the power control apparatus does, so damage to the power control apparatus can be reduced. 
         [0012]    A portion of the auxiliary battery may be arranged by the connecting portion so as to be positioned next to a side of the power control apparatus. With this kind of arrangement, the auxiliary battery is able to move without losing its posture, by being guided to the side of the power control apparatus. 
         [0013]    Also, the connecting portion may be able to move in the crushing direction by displacement of the displaceable member, and may move the auxiliary battery without inhibiting the vehicle frame member from being crushed by the impact load. In this way, the connecting portion is able to move the auxiliary battery by displacement due to crushing of the vehicle frame member and the displacement of the connecting portion itself. 
         [0014]    Also, the connecting portion may be connected to the vehicle frame member by the displaceable member in at least two locations. Because the auxiliary battery is connected to the displaceable member of the connecting portion, the vehicle frame member is not inhibited from being crushed. 
         [0015]    The power control apparatus and the auxiliary battery may be arranged in this order from a center in a vehicle width direction toward an outside in the vehicle width direction. With this kind of arrangement, when there is an offset collision, the auxiliary battery absorbs the impact before the power control apparatus does, so damage to the power control apparatus can be reduced. 
         [0016]    Furthermore, the motor case may be a double axis type transaxle with two rotary electric machines. The double axis type transaxle has a predetermined dimension in the vehicle longitudinal direction, so the power control apparatus is easily mounted on the transaxle. 
         [0017]    Using the vehicle equipment mounting structure according to the aspect of the invention enables the power control apparatus to be arranged on the motor case, and the auxiliary battery to be arranged on a side member of a vehicle frame member so that it partially overlaps in the vehicle longitudinal direction with the power control apparatus. This mounting structure enables the space in the engine compartment to be utilized. Also, when there is a collision, a barrier penetrates the engine compartment while crushing the vehicle frame member and the support of the auxiliary battery. Consequently, the auxiliary battery moves past the power control apparatus such that the auxiliary battery does not interfere with the power control apparatus. As a result, the power control apparatus is able to be protected and can be rapidly discharged. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: 
           [0019]      FIG. 1  is a top view of an engine compartment showing a vehicle equipment mounting structure according to one example embodiment of the invention; 
           [0020]      FIG. 2  is a side view of the engine compartment showing the vehicle equipment mounting structure according to the example embodiment of the invention; 
           [0021]      FIG. 3  is a view of a state in which a barrier has penetrated the engine compartment shown in  FIG. 1 ; 
           [0022]      FIG. 4  is a view of a state in which the barrier has penetrated the engine compartment shown in  FIG. 2 ; 
           [0023]      FIG. 5  is a perspective view of an auxiliary battery shown in  FIG. 4 ; 
           [0024]      FIG. 6  is a perspective view of a support that supports the auxiliary battery shown in  FIG. 5 ; 
           [0025]      FIG. 7A  is a perspective view of a support that supports an auxiliary battery according to another example embodiment of the invention; and 
           [0026]      FIG. 7B  is a view of deformation of the support when an impact load is applied. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0027]    Hereinafter, example embodiments of the invention will be described in detail with reference to the accompanying drawings. 
         [0028]      FIG. 1  is a view of an engine compartment  20  of a hybrid vehicle  10 , and a vehicle equipment mounting structure for a PCU  13  that is arranged on an upper surface of a motor case  12 , and an auxiliary battery  14 . The structure of the engine compartment  20  will briefly be described with reference to  FIG. 1 . In the engine compartment  20  are provided a side member  15  that is provided on both sides of the hybrid vehicle  10  and is a vehicle frame member, a spring support  16  that is connected to the side member  15 , a front bumper reinforcement  18  that is connected to tip ends of the side member  15 , an engine  11 , the motor case  12  that is connected to the engine  11 , a wheel axle  25  that extends from the motor case  12 , the PCU  13  that is fixed onto the motor case  12 , the auxiliary battery  14  that is fixed by a fixture  22 , a mounting base  21 , and a support  23  onto the side member  15 , and a radiator  17  that is attached to a front portion. Here, the PCU  13  is fixed by a bolt to the motor case  12 , while the auxiliary battery  14  is configured to be able to move along the side member  15  in response to an impact load. 
         [0029]    One characteristic of the vehicle equipment mounting structure according to this example embodiment is that the auxiliary battery  14  is connected to the side member  15  in such a way that a front end portion of the auxiliary battery  14  is farther toward a vehicle front side than a front end portion of the PCU  13  is. This kind of arrangement enables the PCU to be protected. Another characteristic is that the advancing direction of the auxiliary battery  14  that is smaller than the PCU  13  is defined by the fact that a side surface of the auxiliary battery  14  partially overlaps with a side surface of the PCU  13 . Yet another characteristic is that the auxiliary battery  14  is configured to protect the PCU  13  by moving past it when an impact load is applied, by a portion of the auxiliary battery  14  being arranged next to a side of the PCU  13 . In order to create this kind of configuration, in this example embodiment, innovations have been applied to both the mounting position of the auxiliary battery  14  and the support structure of the auxiliary battery  14 . 
         [0030]      FIG. 2  is a side view of  FIG. 1 , and shows the vehicle equipment mounting structure of the PCU  13  arranged on the upper surface of the motor case  12 , and the auxiliary battery  14 . The description related to the structure described with reference to  FIG. 1  will be omitted. The auxiliary battery  14  is fixed onto the side member  15  by the support  23  that is fixed to the side member  15 , the mounting base  21  that is mounted on top of the support  23 , the fixture  22  that fixes the upper portion of the auxiliary battery  14 , and a J-bolt  24  that fixes the fixture  22  to the support  23 . The position in which the auxiliary battery  14  is fixed is farther toward the front of the vehicle than the PCU  13  by a distance that takes crush displacement length into account. As the crush displacement length, a distance is set at which a collision load can be sufficiently absorbed in conjunction with the crush displacement of the front bumper reinforcement  18 , in response to the support  23  being crushed toward the rear of the vehicle without inhibiting the side member  15  from being crushed, when an impact load is applied. 
         [0031]      FIG. 3  is a view of a frontal offset collision in which a barrier has penetrated the engine compartment  20  shown in  FIG. 1 , and  FIG. 4  is a side view of the state shown in  FIG. 3 . As a result of the barrier penetrating the right half of the vehicle following an impact load, the front bumper reinforcement  18  and the radiator  17  are crushed first, and then the side member  15 , a front apron, and the support  23  of the auxiliary battery are crushed. Then the barrier collides with the engine  11  or the motor case  12 . As a result of this deformation and collision, the auxiliary battery  14  moves along the side of the PCU  13  to substantially the same position as the PCU  13 , and as a result, a collision between the PCU  13  and the auxiliary battery  14  is able to be avoided. From this kind of sequential crushing, the impact load is able to be absorbed by the engine compartment  20  and the mounting equipment, so the PCU  13  can be protected and rapidly discharged. Next, the fixing structure of the auxiliary battery  14  will be described in detail. 
         [0032]      FIG. 5  is a perspective view of the auxiliary battery  14  shown in  FIG. 4 . The auxiliary battery  14  is mounted on top of the support  23  that is fixed to a side member. The fixture  22  that fixes the auxiliary battery  14  is provided on the upper surface of the auxiliary battery  14 . The fixture  22  is connected to the support  23  by two J-bolts  24  and nuts  31 . The auxiliary battery  14  is fixed via the mounting base  21  on top of the support  23  by the fixture  22  and the two J-bolts  24  and nuts  31 . Here, the support  23  has a structure that has the necessary strength in the vertical direction to support the weight of the auxiliary battery  14 , but that will not inhibit the side member  15  from being crushed in the crushing direction. The fixture  22  and the two J-bolts  24  that hold the top surface of the auxiliary battery  14  have a structure that moves parallel to the crushing direction in response to deformation of the support  23  and deformation of the side member  15 . Next, the structure of the support  23  will be described in detail. 
         [0033]      FIG. 6  is a perspective view of the support  23  that supports the auxiliary battery shown in  FIG. 5 . The support  23  is fixed to the side surfaces of the side member  15  by fixing portions  33  in four locations. The support  23  is formed by press-forming a thin plate, and includes an expanding and contracting portion that expands and contracts such that a parallelogram is crushed in the longitudinal and parallel direction as the side member  15  is crushed when a collision load indicated by the large arrow in the drawing is applied, and an inhibiting portion  32  that is provided at opposing corners of the parallelogram so as to inhibit expansion and contraction of the expanding and contracting portion up to a predetermined load. The inhibiting portion  32  is designed to maintain the strength of the support  23 . Vibration control and strength are able to be maintained by the inhibiting portion  32 . Moreover, the inhibiting portion  32  allows the expanding and contracting portion to deform by being drawn out by a tensile load from an impact load and deforming until it breaks. At this time, the relative position of the J-bolts  24  that are retained by J-bolt retaining portions  35  moves in the crushing direction by the deformation of the expanding and contracting portion, and the J-bolts  24  on the opposite side move, sliding on a J-bolt moving portion  36 , such that the auxiliary battery  14  moves in the crushing direction. In this way, the auxiliary battery  14  is able to move past the side of the PCU  13  by moving parallel to the crushing direction, without the orientation of the auxiliary battery  14  changing. Next, an example embodiment in which an auxiliary battery is arranged straddling a side member will be described in detail. 
         [0034]      FIG. 7A  is a perspective view of a support  26  that supports an auxiliary battery according to another example embodiment of the invention.  FIG. 7B  is a view of deformation of the support  26  when an impact load is applied. The support  26  shown in  FIG. 7A  is fixed straddling a side member  15  by fixing portions  34  at four locations, by four leg portions  27  and  28 , a mounting surface  29  that is supported by the leg portions, and J-bolt retaining portions  35  and  37  formed on the mounting surface. Therefore, a protruding press-formed portion  37  is provided on each of the four leg portions such that the support  26  will crush relatively easily in the crushing direction when an impact load is applied. As a result, vibration control and strength are able to be maintained. With this kind of shape, the bent portions deform and the parallelogram expands and contracts in the longitudinal and vertical directions when an impact load is applied, as shown in  FIG. 7B , thereby enabling the auxiliary battery to move in the crushing direction without changing the orientation of the auxiliary battery. 
         [0035]    As described above, using the vehicle equipment mounting structure according to the example embodiment makes it possible to utilize the space in the engine compartment by having the power control apparatus arranged on the motor case, and have the auxiliary battery arranged on a side member of a vehicle frame member so that it partially overlaps in the vehicle longitudinal direction with the power control apparatus. Also, when there is a collision, the barrier penetrates the engine compartment while crushing the vehicle frame member and the support of the auxiliary battery. Consequently, the auxiliary battery moves past the power control apparatus such that the auxiliary battery does not interfere with the power control apparatus. As a result, the power control apparatus is able to be protected and can be rapidly discharged. It should be noted that the support illustrated in this example embodiment has the expanding and contracting portion, but the invention is not limited to this. That is, the support may also be configured to move along a guide groove on the side member. 
         [0036]    While the invention has been described with reference to example embodiments thereof, it is to be understood that the invention is not limited to the described embodiments or constructions. To the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the example embodiments are shown in various combinations and configurations, other combinations and configurations, including more, less or only a single element, are also within the scope of the invention.