Abstract:
Provided is an electric automobile that can protect high-voltage components from shocks during impact. The electric automobile, which has a motor room that is separated from the cabin and partitioned at the front of the vehicle body and that houses a driving motor and a power control unit that drives/controls the driving motor, is provided with: a pair of side frames that extend in the front-back direction of the vehicle body at both sides of the vehicle body of the motor room; and a unit support frame that encloses the power control unit on four sides and supports the power control unit. The unit support frame is suspended from the pair of side frames and is fastened to the pair of side frames. The power control unit is supported by the unit support frame at at least the sides excluding that in the backwards direction of vehicle body of the four sides of the unit support frame.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an electric automobile that protects high-voltage components from shocks. 
       BACKGROUND ART 
       [0002]    Gasoline automobiles and hybrid automobiles of the background art have an engine, which functions as a rigid body to absorb shocks produced in the event of a collision, for thereby protecting high-voltage components that are disposed behind the engine. 
         [0003]    Japanese Laid-Open Patent Publication No. 2005-207241 discloses an inverter, which serves as a high-voltage component, and which is disposed rearwardly in an air cleaner housing that is connected to an intake air passage of an engine on a hybrid automobile. The air cleaner housing and the engine are capable of absorbing shocks to protect the inverter in the event of a collision. 
       SUMMARY OF INVENTION 
       [0004]    However, since electric automobiles do not have an engine, electric automobiles are unable to protect high-voltage components from shocks produced in the event of a collision. 
         [0005]    The present invention has been made in view of the foregoing problems of the background art. It is an object of the present invention to provide an electric automobile, which protects high-voltage components from shocks produced in the event of a collision. 
         [0006]    To achieve the above object, in accordance with the invention recited in claim  1 , there is provided an electric automobile having a motor compartment, which houses therein a traction motor and a power control unit for controlling the traction motor, the motor compartment being defined in a front portion of a vehicle body and isolated from a passenger compartment, comprising a pair of side frames disposed in the motor compartment on both sides of the vehicle body, and extending in a longitudinal direction of the vehicle body, and a unit support frame surrounding the power control unit on four sides thereof for supporting the power control unit, wherein the unit support frame is supported on the side frames and secured to the side frames, and the power control unit is supported by the unit support frame with the four sides thereof, except for at least a rear side of the unit support frame with respect to the vehicle body. 
         [0007]    The electric vehicle may further comprise a dashboard panel covering the motor compartment, wherein the unit support frame is fastened to the side frames such that the power control unit is disposed beneath the dashboard panel. 
         [0008]    The power control unit may include wire connectors to which electric power supply lines are connected for supplying electric power to the traction motor, and a guard for guarding the wire connectors. The wire connectors and the guard may be disposed on a side of the power control unit, and the guard may be fastened to the unit support frame. 
         [0009]    A rotational axis of the traction motor and a rotational axis of a differential gear for transmitting drive power of the traction motor to left and right drive road wheels may be coaxial with each other. 
         [0010]    At least a frame, which serves as the rear side of the unit support frame with respect to the vehicle body, out of the four sides thereof, may be of a bent shape, the bent shape being variable as desired. 
         [0011]    According to the invention recited in claim  1 , the unit support frame, which surrounds the power control unit with four sides thereof and supports the power control unit, supports the power control unit with the four sides, except for at least a rear side of the unit support frame with respect to the vehicle body. Consequently, a space is not required to fasten the rear side of the unit support frame and the power control unit to each other. Thus, due to such a space, the power control unit can be brought rearwardly with respect to the vehicle body, resulting in an increased crushable zone. Therefore, any adverse effects that shocks, which are produced in the event of a collision, have on the power control unit are reduced. Hence, the power control unit, which is a high-voltage component, is protected. 
         [0012]    According to the invention recited in claim  2 , since the unit support frame is disposed beneath the dashboard panel, the user is prevented from easily accessing the power control unit. Furthermore, when the power control unit is fabricated, the power control unit can be fabricated at a low cost, while reducing concerns in relation to a pedestrian protection area of the vehicle body. 
         [0013]    According to the invention recited in claim  3 , the power control unit includes the guard for guarding the wire connectors, to which electric power supply lines for supplying electric power to the traction motor are connected. Therefore, the wire connectors, which are high-voltage wire connectors, are protected from shocks produced in the event of a collision. 
         [0014]    According to the invention recited in claim  4 , since the rotational axis of the differential gear and the rotational axis of the traction motor are coaxial with each other, the traction motor can be installed in a low position, thereby allowing the power control unit to be installed between the dashboard panel and the traction motor without reducing the height of the electric automobile or the height of the power control unit. Therefore, the vehicle body of the electric automobile can be designed with increased freedom, and costs for the power control unit can be reduced. 
         [0015]    According to the invention recited in claim  5 , since out of the four sides of the unit support frame, the bent shape of the frame at the rear side thereof with respect to the vehicle body can be varied as desired, the power control unit can be placed in as rearward a position as possible with respect to the vehicle body, so as to be out of interference with components in the vicinity of the dashboard panel. In addition, the assembly constituted by the power control unit and the unit support frame is made compact. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0016]      FIG. 1  is a schematic perspective view showing a general arrangement of an electric automobile; 
           [0017]      FIG. 2  is a schematic side elevational view showing a general arrangement of the electric automobile; 
           [0018]      FIG. 3  is a perspective view of a power control unit shown in  FIGS. 1 and 2 , and a unit support frame supporting the power control unit; 
           [0019]      FIG. 4  is a view showing the relationship between the power control unit, a motor-driven power device, and three-phase electric power cables; 
           [0020]      FIG. 5  is a fragmentary perspective view showing a general frontal arrangement of a vehicle body of the electric automobile; 
           [0021]      FIG. 6  is a view showing the relationship between a dashboard panel lower member and a rear support frame with the power control unit mounted on a vehicle body; and 
           [0022]      FIG. 7  is a cross-sectional view of the motor-driven power device. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0023]    An electric automobile having a mounting structure for mounting a power control unit on a vehicle body, and a mounting structure of the power control unit according to a preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. 
         [0024]      FIG. 1  is a schematic perspective view showing a general arrangement of an electric automobile  10 , and  FIG. 2  is a schematic side elevational view showing a general arrangement of the electric automobile  10 . In  FIGS. 1  and  2 , mechanisms and components, which have no bearing on the present invention, are omitted from illustration. In the present embodiment, vertical directions of a vehicle body  12  are referred to as such, and directions perpendicular to the vertical directions are referred to as horizontal directions. The direction in which the electric automobile  10  travels in a forward direction is referred to as a front direction, the direction in which the electric automobile  10  travels in reverse is referred to as a rear direction, the leftward direction as viewed along the direction in which the electric automobile  10  travels forward is referred to as a left direction, and the right direction as viewed along the direction in which the electric automobile  10  travels forward is referred to as a right direction. 
         [0025]    The electric automobile  10  contains within the vehicle body  12 , between the front road wheels  14 L,  14 R and the rear road wheels  16 L,  16 R, a battery  18 , which is mounted on the bottom wall of the vehicle body  12  for outputting a high voltage, a passenger compartment  22  defined by a floor panel  20  above the battery  18 , a motor compartment  24  defined in a front portion of the vehicle body  12 , which is isolated from the passenger compartment  22 , a dashboard panel  26  that covers the motor compartment  24 , and a power control unit  30  positioned above a motor-driven power device  28  that is disposed in the motor compartment  24 . The dashboard panel  26  has a dashboard panel lower member  26   a  and a dashboard panel upper member  26   b.  The dashboard panel  26  separates the motor compartment  24  and the passenger compartment  22  from each other, and has a structure for preventing dirt, water, odor, etc., from entering into the passenger compartment  22  from the motor compartment  24 . The dashboard panel  26  also has a water draining function, which serves to prevent external water from flowing into A/C (air conditioner) pipes, to be described later. 
         [0026]    The power control unit  30  is disposed beneath the dashboard panel  26 . Therefore, the dashboard panel upper member  26   b  must be removed when the power control unit  30  is serviced for maintenance. Accordingly, the user is prevented from easily gaining access to the power control unit  30 , which is a high-voltage component. 
         [0027]    The vehicle body  12  includes a motor hood  12   a  that extends above a pedestrian protection area  32  for reducing shocks that may be applied to a pedestrian in the event of a collision. Components such as the power control unit  30  cannot be placed within the pedestrian protection area  32 . Therefore, the power control unit  30  must be fabricated in such a way so as not to interfere with the pedestrian protection area  32 . According to the present embodiment, since the power control unit  30  is disposed beneath the dashboard panel  26 , the power control unit  30  can be fabricated with reduced concern in relation to the pedestrian protection area  32 , and hence the power control unit  30  can be fabricated at a reduced cost. 
         [0028]    Power supply cables  34  serve to transmit electric power stored in the battery  18  to the power control unit  30 . Ends of the power supply cables  34  are connected to a power supply connector  36  of the battery  18 , and other ends thereof are connected to a power supply connector of the power control unit  30 , to be described later. The power control unit  30  converts DC electric power supplied from the battery  18  into AC electric power in three phases (U, V, W phases), and supplies the three-phase AC electric power to a traction motor of the motor-driven power device  28 , to thereby energize the traction motor. 
         [0029]    The power control unit  30  has an inverter for converting DC electric power into three-phase AC electric power, and a controller for controlling the inverter (not shown). The traction motor of the motor-driven power device  28  and the power control unit  30  are connected to each other by three-phase AC electric power cables (electric power supply lines)  38 . Ends of the three-phase AC electric power cables  38  are connected to electric power connectors (motor-side connectors)  40  of the traction motor, and other ends thereof are connected to electric power connectors (wire connectors)  42  of the power control unit  30 . Since the power control unit  30  is disposed above the motor-driven power device  28 , the three-phase AC electric power cables  38 , which are high-voltage cables, may be reduced in length. The power control unit  30  is mounted in the motor compartment  24  of the vehicle body  12  by a unit support frame and a pair of side frames (mount frames), which will be described below. 
         [0030]      FIG. 3  is a perspective view of the power control unit  30  shown in  FIGS. 1 and 2 , and a unit support frame  44  supporting the power control unit  30 .  FIG. 4  is a view showing the relationship between the power control unit  30 , the motor-driven power device  28 , and the three-phase AC electric power cables  38 . Power supply connectors  46  are disposed on an upper portion of the power control unit  30 , and the electric power connectors  42  are disposed on a side face (left side face) of the power control unit  30 . The power supply connectors  46  are mounted on the power control unit  30 , and are disposed in a recess  48  defined in the power control unit  30 , so that the power supply cables  34 , which are connected to the power supply connectors  46 , are oriented in a rearward horizontal direction. 
         [0031]    The upper portion of the power control unit  30  includes a ledge  50 , which projects outwardly from the side face (left side face) thereof in a horizontal direction of the vehicle body  12 . The electric power connectors  42  are mounted on a bottom surface of the ledge  50 . The electric power connectors  42  are mounted on the power control unit  30  in such a manner that the three-phase AC electric power cables  38 , which are connected to the electric power connectors  42 , hang downwardly along a vertical direction of the vehicle body  12 . Thus, the electric power connectors  42  are prevented from directly suffering shocks produced in the event of a collision. 
         [0032]    The power control unit  30  has a guard  52 , which surrounds the three-phase AC electric power cables  38  that are connected to the electric power connectors  42 , for thereby guarding the three-phase AC electric power cables  38 , the ledge  50 , and the electric power connectors  42 . The guard  52  projects from a side face (left side face) of the power control unit  30  in the horizontal direction of the vehicle body  12 , and projects outwardly beyond the ledge  50  (see  FIG. 4 ). The guard  52  has a cavity defined therein through which the three-phase AC electric power cables  38  extend and are connected to the electric power connectors  42  (see  FIG. 6 ). The guard  52  is disposed in an intermediate position between the vertical position of the electric power connectors  40  of the traction motor and the vertical position of the electric power connector  42  of the power control unit  30 . The guard  52  is formed integrally with the housing of the power control unit  30 . 
         [0033]    Since the guard  52  is provided on the housing of the power control unit  30 , the electric power connectors  42  can be protected without the need for an increased number of man-hours or components. The guard  52  on the housing of the power control unit  30  surrounds the three-phase AC electric power cables  38 , which are connected to the electric power connectors  42 , and therefore, the three-phase AC electric power cables  38  are prevented from experiencing forces due to shocks produced in the event of a collision. Therefore, any stresses, which would otherwise be applied to the three-phase AC electric power cables  38  by forces due to shocks produced in the event of a collision, are reduced or eliminated, thereby protecting the electric power connectors  42 . 
         [0034]    Since the guard  52  projects outwardly beyond the ledge  50 , the guard  52  protects the ledge  50  from shocks produced in the event of a collision, thereby effectively protecting the electric power connectors  42 , the ledge  50 , and the three-phase AC electric power cables  38 . Furthermore, since the guard  52  is disposed in an intermediate position between the electric power connectors  40  and the electric power connectors  42 , the guard protects the electric power connectors  42 , the ledge  50 , and the three-phase AC electric power cables  38  more effectively. In order to effectively protect the electric power connectors  42 , etc., preferably, the aforementioned intermediate position should be located at about one-half the distance L from a vertical position H 1  of the electric power connectors  40  to a vertical position H 2  of the electric power connectors  42  (i.e., the distance from the vertical position H 1  of the electric power connectors  40  to the vertical position of the guard  52  is represented by L/2) (see  FIG. 4 ). 
         [0035]    Inasmuch as the guard  52  is disposed in surrounding relation to the three-phase AC electric power cables  38  that are connected to the electric power connectors  42 , rather than in surrounding relation to the electric power connectors  42 , the electric power connectors  42  are capable of being viewed, thereby making it easy for the user to connect the three-phase AC electric power cables  38  to the electric power connectors  42 . 
         [0036]    The unit support frame  44  includes a left side support frame  54 , a right side support frame  56  lying substantially parallel to the left side support frame  54 , a front support frame  58  extending between the left side support frame  54  and the right side support frame  56 , and a rear support frame  60  extending between the left side support frame  54  and the right side support frame  56  at a location behind the front support frame  58 . The unit support frame  44  supports the power control unit  30 , which is surrounded by the four support frames  54 ,  56 ,  58 ,  60 , the four support frames  54 ,  56 ,  58 ,  60  being positioned on the four sides of the unit support frame  44 . The front support frame  58 , the right side support frame  56 , and the left side support frame  54  are fastened by bolts B to the power control unit  30 . 
         [0037]    More specifically, the front support frame  58  and a front portion of the power control unit  30  are fastened to each other by bolts B, and the right side support frame  56  and a right side face of the power control unit  30  are fastened to each other by bolts B. The guard  52 , which is located on the side face (left side face) of the power control unit  30 , and the left side support frame  54  are fastened to each other by bolts B. In other words, the power control unit  30  is supported on three sides thereof by the unit support frame  44 . Further, since the guard  52  is fastened to the left side support frame  54 , the mechanical strength of the guard  52  is increased, thereby increasing the protective capability. Accordingly, the electric power connectors  42 , etc., are protected more strongly. 
         [0038]      FIG. 5  is a fragmentary perspective view showing in general the front arrangement of the vehicle body  12  of the electric automobile  10 .  FIG. 5  shows a front portion of the vehicle body  12  with the motor hood  12   a  being open. In  FIG. 5 , mechanisms and components, which have no bearing on the present invention and the motor-driven power device  28 , are omitted from illustration. 
         [0039]    The front portion of the vehicle body  12  includes a pair of side frames  64 ,  64  disposed on both sides of the vehicle body  12  and extending in the longitudinal direction of the vehicle body  12 . The unit support frame  44  is supported on the side frames  64 ,  64  and is secured thereto by four support legs  62 , which are fastened to the side frames  64 ,  64  by bolts B. In order to minimize adverse effects caused by shocks produced in the event of a collision, the unit support frame  44  is positioned as rearwardly as possible. In other words, the unit support frame  44  is brought as close as possible to the dashboard panel lower member  26   a.    
         [0040]    Upon securing the power control unit  30  to the unit support frame  44  that is fastened to the side frames  64 ,  64 , if a rear portion of the power control unit  30  and the rear support frame  60  were fastened to each other by bolts B, then a space for tightening the bolts would be required behind the power control unit  30 . Therefore, when the unit support frame  44  is fastened to the side frames  64 ,  64 , the unit support frame  44  has to be brought forward by the aforementioned space, resulting in the power control unit  30  being installed in a forward position. 
         [0041]    On the other hand, according to the present embodiment, the power control unit  30  is supported by the support frames other than the rear support frame  60 , such that the rear support frame  60  and the power control unit  30  are not fastened to each other. Consequently, the power control unit  30  is positioned as rearwardly as possible, thereby reducing adverse effects that shocks produced in the event of a collision exert on the power control unit  30 . In other words, since the power control unit  30  is positioned as rearwardly as possible, the vehicle body  12  has an increased crushable zone (see  FIG. 2 ), thereby reducing adverse effects that shocks produced in the event of a collision have on the power control unit  30 , and hence protecting the power control unit  30 , which is a high-voltage component. Since the crushable zone can be increased, the vehicle body  12  can be designed with increased freedom. Furthermore, inasmuch as the power control unit  30  is brought to as rearward a position as possible, the length of the power supply cables  34 , which are high-voltage cables, can be reduced. 
         [0042]    Furthermore, since the rear support frame  60  does not support the power control unit  30 , even if the power control unit  30  moves rearwardly as a result of shocks that are produced in the event of a collision, any forces that act to block the rearward movement of the power control unit  30  are not produced behind the power control unit  30  until the power control unit  30  actually hits against the rear support frame  60 . Therefore, any adverse effects that shocks, which are produced in the event of a collision, have on the power control unit  30  are reduced. 
         [0043]      FIG. 6  is a view showing the relationship between the dashboard panel lower member  26   a  and the rear support frame  60 , with the power control unit  30  being mounted on the vehicle body  12 . A/C pipes  66  extend from the motor compartment  24 , through the dashboard panel lower member  26   a,  and into the passenger compartment  22 . Other parts such as brake pipes  68  or the like are disposed in the vicinity of the dashboard panel lower member  26   a.  Therefore, the rear support frame  60  has a bent shape, so as not to interfere with other parts including the A/C pipes  66  and the brake pipes  68 , i.e., parts located in the vicinity of the dashboard panel lower member  26   a.  In other words, the bent shaped of the rear support frame  60  may be varied as desired. The assembly consisting of the power control unit  30  and the unit support frame  44  can be made compact in size, thus allowing the unit support frame  44  to be positioned in a more rearward location, i.e., closer to the dashboard panel  26 . Accordingly, any adverse effects that shocks produced in the event of a collision have on the power control unit  30  are reduced, thus enabling the power control unit  30 , which is a high-voltage component, to be protected. 
         [0044]      FIG. 7  is a cross-sectional view of the motor-driven power device  28 . The motor-driven power device  28  includes a traction motor  100 , a speed reducer  102 , and a differential gear  104 , which are combined in an integral assembly. The motor-driven power device  28  includes an outer housing comprising a transmission case  106  positioned at a left end thereof in the transverse direction of the vehicle body  12 , a motor transmission case  108  fastened by bolts  107  to the right end of the transmission case  106 , a central motor case  110  fastened by non-illustrated bolts to the right end of the motor transmission case  108 , a side motor case  112  fastened by non-illustrated bolts to the right end of the central motor case  110 , a central shaft bearing support  114  fastened by non-illustrated bolts to the right end of the side motor case  112 , and an intermediate case  118  fastened by bolts  107  to an inner surface of the transmission case  106 . The traction motor  100  is accommodated in the motor transmission case  108 , the central motor case  110 , and the side motor case  112 , whereas the speed reducer  102  and the differential gear  104  are accommodated in the transmission case  106  and the motor transmission case  108 . 
         [0045]    The traction motor  100  includes a stator  120 , which is fixed to an inner circumferential surface of the central motor case  110 , and a rotor  122  rotatably disposed inside of the stator  120 . The stator  120  has a plurality of stator cores  124 , each comprising stacked steel plates, disposed in a circumferential array, and a plurality of coils  126  wound respectively around the stator cores  124 . The rotor  122  has a hollow rotor shaft  132 , which is rotatably supported by respective ball bearings  128 ,  130  on the motor transmission case  108  and the side motor case  112 , a rotor core  134  comprising stacked steel plates fixedly mounted on the rotor shaft  132 , and a plurality of permanent magnets  136  embedded in an outer circumferential surface of the rotor core  134 . The rotor core  134  has a plurality of through holes  138  that extend axially therethrough. 
         [0046]    The speed reducer  102  has a speed reducer shaft  144 , which is supported respectively by a roller bearing  140  and a ball bearing  142  on the transmission case  106  and the motor transmission case  108 . The speed reducer  102  also has a second speed reducer gear  146 , a parking gear  148 , and a final drive gear  150 , which are mounted on the speed reducer shaft  144 . The speed reducer  102  further includes a first speed reducer gear  152  mounted on the left end of the rotor shaft  132 , and which is held in mesh with the second speed reducer gear  146  of the speed reducer shaft  144 . The final drive gear  150  of the speed reducer shaft  144  is held in mesh with a final driven gear  154  of the differential gear  104 . 
         [0047]    The differential gear  104  includes a differential case  160 , which is supported rotatably on the transmission case  106  and the intermediate case  118 , respectively, by tapered roller bearings  156 ,  158 , a pair of differential pinions  164 ,  164  which are supported rotatably on the differential case  160  by a pinion pin  162 , and a pair of differential side gears  166 ,  166  which are held in mesh simultaneously with both of the differential pinions  164 ,  164 . The final driven gear  154  is fixed to an outer circumferential surface of the differential case  160 . 
         [0048]    A left drive shaft  168  having a right end thereof splined to the left differential side gear  166  extends through the differential case  160  and the transmission case  106 , in a leftward transverse direction of the vehicle body  12 . A central shaft (half shaft)  170  having a left end thereof splined to the right differential side gear  166  extends through the differential case  160 , the transmission case  106 , and the hollow rotor shaft  132 , in a rightward transverse direction of the vehicle body  12 . A right drive shaft  174  is splined to the central shaft  170 , the right end of which is supported on the central shaft bearing support  114  by a ball bearing  172 . The front road wheel  14 L is connected to the left drive shaft  168 , and the front road wheel  14 R is connected to the right drive shaft  174 . 
         [0049]    When the traction motor  100  is energized, torque (rotational power) of the rotor shaft  132  is transmitted through the first speed reducer gear  152  and the second speed reducer gear  146  to the speed reducer shaft  144 . From the speed reducer shaft  144 , the torque is transmitted through the final drive gear  150  and the final driven gear  154  to the differential case  160 . The torque, which is transmitted to the differential case  160 , is distributed via the differential pinions  164  and the differential side gears  166  at a given ratio to the left drive shaft  168 , the central shaft  170 , and the right drive shaft  174 , depending on how the electric automobile  10  is being turned. Consequently, when the traction motor  100  is energized, the front road wheels  14 L,  14 R are rotated. 
         [0050]    Since the rotational axis of the traction motor  100  and the rotational axis of the differential gear  104  are coaxial with each other, the motor-driven power device  28  can be installed in a low position, thereby allowing the power control unit  30  to be installed between the dashboard panel  26  and the traction motor  100 , without requiring a reduction in the height of the electric automobile  10  or a reduction in the height of the power control unit  30  in the vertical direction of the vehicle body  12 . In other words, since the installation position of the motor-driven power device  28  is lowered, the space defined between the dashboard panel upper member  26   b  of the dashboard panel  26  and the motor-driven power device  28  is increased. Therefore, the vehicle body  12  of the electric automobile  10  can be designed with increased freedom, and the cost of the power control unit  30  can be reduced. 
         [0051]    According to the present embodiment, the power control unit  30  is surrounded by the four sides of the unit support frame  44 , and is supported by the sides of the unit support frame  44 , except for the rear side of the unit support frame  44 , with respect to the vehicle body  12 . More specifically, the power control unit  30  is supported by the left side support frame  54 , the right side support frame  56 , and the front support frame  58 . Consequently, a space is not required for fastening the power control unit  30  with bolts B to the rear side (the rear support frame  60 ) of the unit support frame  44 , which is fastened to the side frames  64 ,  64 . The power control unit  30  can thus be brought rearwardly with respect to the vehicle body  12  into such a space, resulting in an increased crushable zone. Therefore, any adverse effects that shocks may have on the power control unit  30  in the event of a collision are reduced. Thus, the power control unit  30 , which is a high-voltage component, is protected. 
         [0052]    Since the unit support frame  44  is disposed beneath the dashboard panel  26 , the user is prevented from easily gaining access to the power control unit  30 . Furthermore, since the unit support frame  44  is disposed beneath the dashboard panel  26 , the power control unit  30  can be fabricated with less concern in relation to the pedestrian protection area  32 , and hence, the power control unit  30  can be fabricated at a reduced cost. 
         [0053]    The electric power connectors  42 , to which the three-phase AC electric power cables  38  are connected in order to supply electric power to the traction motor  100 , and the guard  52 , which guards the electric power connectors  42 , are mounted on the power control unit  30 . In addition, the guard  52  is fastened to the unit support frame  44  that supports the power control unit  30  thereon. Consequently, the mechanical strength of the guard  52  is increased for increasing the protective capability thereof. Accordingly, the electric power connectors  42 , which are high-voltage connectors, are protected from shocks produced in the event of a collision, and thus are protected in a more robust manner. 
         [0054]    The electric power connectors  42  are mounted on the bottom surface of the ledge  50 , which projects outwardly from the left side face of the upper portion of the power control unit  30 , in a direction perpendicular to the vertical direction of the vehicle body  12 . The guard  52 , which has a cavity defined therein, projects outwardly from the left side face beyond the ledge  50 , in a direction perpendicular to the vertical direction of the vehicle body  12 . The three-phase AC electric power cables  38  extend through the cavity and are connected to the electric power connectors  42 . Therefore, the three-phase AC electric power cables  38  and the electric power connectors  42  are effectively protected from shocks produced in the event of a collision. 
         [0055]    Since the guard  52  is disposed between the electric power connectors  40 , by which the three-phase AC electric power cables  38  are connected to the traction motor  100 , and the electric power connectors  42 , the electric power connectors  42  are protected more effectively. 
         [0056]    In the above embodiment, the unit support frame  44  supports the power control unit  30  through the frames, with the exception of the rear support frame  60 . However, the unit support frame  44  may not necessarily support the power control unit  30  with at least the rear support frame  60  out of the four sides. In other words, at least the rear support frame  60  out of the four sides and the power control unit  30  may not necessarily be fastened to each other by bolts B. Therefore, the unit support frame  44  may support the power control unit  30  with only the left side support frame  54  and the right side support frame  56 , for example. Although the unit support frame  44  and the power control unit  30  are fastened to each other by bolts B in the above embodiment, they may be fastened to each other by other fastening members apart from the bolts B. 
         [0057]    In the above embodiment, the power control unit  30  lies horizontally (upper and lower surfaces of the power control unit  30  lie horizontally). However, the power control unit  30  may be oriented obliquely. The guard  52  may be mounted on a side face (left side face) of the power control unit  30 , which is mounted on the vehicle body  12  by the unit support frame  44 , such that when the electric power connectors  42  and the guard  52  project in a vertical direction of the vehicle body  12 , the projected image of the guard  52  surrounds projected images of the electric power connectors  42 . 
         [0058]    Although a preferred embodiment of the present invention has been described above, the technical scope of the invention is not limited to the range of the above description of the embodiment. It will be obvious to those skilled in the art that various changes and improvements can be made to the above embodiment. Such changes and modifications also fall within the technical scope of the invention, as is apparent from the scope of the invention as set forth in the appended claims.