Patent Publication Number: US-2013241282-A1

Title: Structure For Routing High-Voltage Cable in Vehicle

Description:
TECHNICAL FIELD 
     The present invention relates to a wiring structure for a high voltage cable for a vehicle. 
     More particularly, the present invention relates to a wiring structure for a high voltage cable used to connect a battery to a generator or a motor or an inverter in a high voltage energy system which is mounted in an electric vehicle (referred also to as an “EV”), the electric vehicle in a broad sense includes a hybrid electric vehicle (referred also to as an “HEV”) and a fuel cell hybrid electric vehicle (referred also to as an “FCV”). Furthermore, the present invention also relates to an arrangement structure on a vehicle for ensuring necessary performance in association with the passive safety of the vehicle. 
     BACKGROUND ART 
     Among electric vehicles in a broad sense, particularly, the hybrid electric vehicle has mounted a large battery (referred also to as a “battery pack” or a “cell”) and a fuel tank in a rear portion of the vehicle body of the vehicle. Regarding the high voltage energy system, in wiring the high voltage cable used to connect a battery to a generator or a motor or an inverter, the high voltage cable is laid on a portion near the center in the vehicle width direction on the lower surface of a vehicle body floor so as to extend along the vehicle front and rear direction. 
     That is to say, as shown in  FIGS. 8 and 9 , a mounting unit  107  is provided in a front chamber (hereinafter, referred to as an “engine compartment”)  103  formed in front of a dash panel  102  of a vehicle  101 , is provided in rear of right and left headlights (also described as “H/L&#39;s”)  104 , and is provided between the right and left headlights  104 . 
     In this configuration, as shown in  FIG. 8 , the mounting unit  107  is formed by a plurality of detail units. The detail units include an engine  111  configuring a power unit which is arranged on the right-hand side in the vehicle width direction in the engine compartment  103 ; a generator  112  which is arranged on the left-hand side of the engine  111 , that is to say, near the center in the vehicle width direction; a driving motor (also described simply as a “motor”)  113  which is arranged on the rear side in the vehicle front and rear direction of the generator  112 ; and a gear case  114  which is arranged on the rear side in the vehicle front and rear direction of the engine  111  and is arranged on the right-hand side in the vehicle width direction of the driving motor  113 . Furthermore, an inverter  115  is arranged on the left-hand side, in the vehicle width direction, of the generator  112  and the driving motor  113 . 
     For example, the inverter  115  of the mounting unit  107  is connected to a battery (not shown, also referred to as a “cell”) by a high voltage cable  109 . 
     That is to say, when this high voltage cable  109  is wired, as shown in  FIGS. 8 and 9 , the high voltage cable  109  connecting with the battery is laid so as to extend in a portion near the center in the vehicle width direction and in a lower portion in the upper and lower direction, from the rear toward the front in the vehicle front and rear direction. 
     The high voltage cable  109  rises upward in the rear of the driving motor  113  after passing through the dash panel  102  and reaching the engine compartment  103 . 
     When reaching a height position higher than the generator  112  and the driving motor  113 , the high voltage cable  109  runs from the portion near the center in the vehicle width direction toward the left-hand side, reaches the rear side of the inverter  115 , and then, is connected to the inverter  115 . 
     That is to say, the high voltage cable  109  is laid so as to protect the high voltage energy system including the high voltage cable  109  against an external force which is applied from all sides to the vehicle. 
     However, for example, at the front collision time at which an external force is applied to a front portion of the vehicle, as shown in  FIG. 10 , the engine compartment  103  is depressed, and the mounting unit  107  which is mounted in the engine compartment  103  and includes the engine  111 , the generator  112 , the driving motor  113 , and the gear case  114 , is retracted to the rear side in the vehicle front and rear direction, and the mounting unit  107  comes into contact with the dash panel  102 . 
     At this time, the high voltage cable  109  is held between the mounting unit  107  and the dash panel  102  as indicated by the hatched portion shown in  FIGS. 10 and 11 , and therefore, there arises a problem that the high voltage cable  109  may be damaged. 
     As a solution to the above-described problem, it can be thought that the portion of the high voltage cable  109  which is located between the mounting unit  107  and the dash panel  102  is covered firmly with a protective member that includes a sheet metal cover, a resin protector, or the like. 
     On the other hand, in the case in which the generator, the driving motor, and the inverter are mounted crowded together in the engine compartment accommodating the power unit, a plurality of high voltage cables must be wired between the generator and the inverter and must be wired between the driving motor and the inverter, and the high voltage cables occupy a considerably large space even if the high voltage cables are wired in an orderly way so as to have the necessary minimum length. 
     In order to protect the high voltage cable from suffering damage, the high voltage cable is covered with a protective member having high strength and high rigidity. 
     On the hybrid electric vehicle mounted with an engine, it is necessary to provide a fuel supply system for supplying fuel to the engine and an exhaust system for exhausting combustion gas from the engine. 
     When the high voltage cable is wired, it has been considered to make the high voltage cable be apart from the fuel supply system and exhaust system. 
     The fuel supply system, the exhaust system, and the high voltage cable are arranged separately; for example, the exhaust system is disposed along a floor center tunnel, the fuel supply system is disposed on one floor of right and left floors with the center tunnel being held therebetween, and the high voltage cable is laid on the other floor thereof. 
     It is a concern to prevent interaction as much as possible, and it is a concern to ensure reliability in the ordinary specification range. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Japanese Patent No. 3838505 
     SUMMARY OF INVENTION 
     Technical Problem 
     PTL 1 discloses a hybrid electric vehicle that is modified such that a motor generator, a battery, and the like are provided on a gasoline-fueled vehicle basically using an engine as a power unit so as to be added to the gasoline-fueled vehicle, whereby the driving can be assisted, or regenerative generation of electric power can be performed. 
     This vehicle is not deemed to be an electric vehicle because it cannot be run by a motor only; this vehicle is a hybrid electric vehicle. 
     This vehicle is mounted with a high voltage energy system which includes a battery, a generator or a motor, an inverter, and a high voltage cable, and also includes an engine and a fuel tank. 
     The change of vehicle body is restricted so as to be very small as a modified vehicle. However, when paying attention to the high voltage cable, the high voltage cable is laid under the fuel tank and the floor from the battery and inverter which are mounted at the rear, to the engine so as to be exposed externally, and as a result, necessary performance is ensured. 
     PTL 1 discloses a hybrid electric vehicle characterized by having a structure in which the high voltage cable is laid near a dash panel. 
     In the case in which an electric vehicle is configured as a base for a compact small-sized vehicle, a ratio which is to provide a passenger space in a portion near the vehicle center and is to ensure comfort, increases, and on the other hand, it is desirable that the engine compartment in the front portion of the vehicle be as small as possible. 
     In the case in which the engine, the generator, the driving motor, and the inverter are mounted crowded together in the engine compartment accommodating the power unit, the occupation space and the interference regarding arrangements of these components and furthermore layout of the high voltage cable, must be considered. 
     Even in the case in which the vehicle front portion is damaged by an external force, it is necessary to avoid effects exerted on the high voltage energy system as much as possible. 
     That is to say, the high voltage cable is prevented from being held between the components and from being damaged, and as a result, the probability of short circuit can be reduced significantly. 
     If the above-described protective member is provided between the components, there arises a problem of increased probability that the gap is narrowed, and the components come into contact with each other. Therefore, although this is unavoidable in the case in which the protective member is provided when it is always necessary for thermal insulation or the like, it is desirable to provide the protective member in an ample space avoiding the above-described location. 
     That is to say, the structure of the related art disclosed in  FIGS. 8 and 9  causes the problem to arise. 
     In the wiring structure disclosed in Japanese Unexamined Patent Application Publication No. 2004-148851, the inverter and the like are not accommodated in the engine compartment (front chamber), and the generator and the driving motor are configured as one unit which is a motor generator. Therefore, the occupied space is small, even a smaller engine compartment has relatively surplus space, and necessary performance is ensured. 
     However, it is desirable to make further improvement. 
     Objects of the present invention are to avoid an influence on a high voltage cable as much as possible even in the case in which a vehicle suffers damage such that the vehicle is deformed greatly by an external force, are to keep the number of fitting parts for protecting the high voltage cable small, and are to make a front chamber accommodating a mounting unit, the high voltage cable, and the like as compact as possible. 
     Solution to Problem 
     To achieve the above objects, the present invention provides a wiring structure for a high voltage cable for a vehicle, including a mounting unit provided in a front chamber which is arranged in the front of a dash panel; and a battery provided in the rear of the dash panel; wherein the high voltage cable is arranged along the dash panel, the high voltage cable being connected to the battery and extending toward the vehicle front portion; wherein a plurality of detail units configuring the mounting unit are aligned in the vehicle width direction in front of the dash panel; wherein the rear surfaces of the detail units are formed so as to make a positional difference in the vehicle front and rear direction, and the rear surfaces thereof have different distances from the dash panel respectively; and wherein the high voltage cable is wired so as to run in a dash panel portion facing to the rear surface of the detail unit on one side on which the distance from the dash panel is greater than that on another side. 
     Advantageous Effects of Invention 
     As explained in detail above, according to the present invention, a wiring structure of a high voltage cable for a vehicle, including: a mounting unit provided in a front chamber which is arranged in front of a dash panel; and a battery provided in rear of the dash panel; wherein the high voltage cable is provided so as to run along the dash panel, the high voltage cable being connected to the battery and extending toward the vehicle front; wherein a plurality of detail units configuring the mounting unit are aligned in the vehicle width direction in front of the dash panel; wherein the rear surfaces of the detail units are formed so as to produce a positional difference in the vehicle front and rear direction, and the rear surfaces thereof have different distances from the dash panel respectively; and wherein the high voltage cable is wired so as to run in a dash panel portion facing to the rear surface of the detail unit on one side on which the distance from the dash panel is greater than that on another side. 
     Therefore, when the mounting unit moves to the rear, and comes into contact with the dash panel, a gap is ensured by the positional difference, and the high voltage cable can be prevented from being damaged. Furthermore, even when contact does not occur, a space can be ensured, interference can be avoided, and a work space can be maintained. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic plan view of an engine compartment in front of a dash panel of a vehicle. (Embodiment) 
         FIG. 2  is a schematic front view taken along arrow mark C of  FIG. 1 . (Embodiment) 
         FIG. 3  is a schematic plan view of an engine compartment in front of a dash panel of a vehicle at the time of front collision. (Embodiment) 
         FIG. 4  is a schematic plan view of a vehicle. (Embodiment) 
         FIG. 5  is a bottom perspective view of a floor panel portion of a vehicle. (Embodiment) 
         FIG. 6  is a schematic left side view of an engine compartment in front of a dash panel of a vehicle. (Embodiment) 
         FIG. 7  is a schematic bottom plan view of an engine compartment portion in front of a dash panel of a vehicle. (Embodiment) 
         FIG. 8  is a schematic plan view of an engine compartment in front of a dash panel of a vehicle, showing a related art of the present invention. 
         FIG. 9  is a schematic front view taken along arrow mark A of  FIG. 8 . 
         FIG. 10  is a schematic plan view of an engine compartment in front of a dash panel of a vehicle at the time of front collision. 
         FIG. 11  is a schematic front view taken along arrow mark B of  FIG. 10 . 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. 
     Embodiment 
       FIGS. 1 to 7  show the embodiment of the present invention. 
     In  FIGS. 4 to 6 , reference numeral “ 1 ” denotes a vehicle, reference numeral “ 2 ” denotes a dash panel, reference numeral “ 3 ” denotes a front chamber, that is to say, an engine compartment in front of the dash panel  2  of the vehicle  1 , reference numeral “ 4 ” denotes a headlight, reference numeral “ 5 ” denotes a front wheel, and reference numeral “ 6 ” denotes a rear wheel. 
     The engine compartment  3 , which corresponds to the front chamber of the vehicle  1 , includes: a mounting unit (capable of being referred also to as an “engine assy” or an “engine assembly”)  7 ; and a battery (referred also to as a “battery pack” or a “cell”)  8  which is arranged in rear of the dash panel  2 . A high voltage cable  9  is connected to the battery  8 , extends toward the vehicle front portion, and rises along the dash panel  2 . 
     That is to say, in the wiring structure of the high voltage cable  9  for the vehicle  1 , as shown in  FIG. 4 , an inverter  15 , described later, is disposed in the mounting unit  7  which is provided in the engine compartment  3  of the vehicle  1 . On the other hand, the battery  8  is provided between the rear wheels  6  at the rear of the vehicle  1 , and is provided in a cargo compartment (not shown) which is arranged above a floor panel (referred also to as a “vehicle body floor”)  26 , described later. When the battery  8  and the inverter  15  of the mounting unit  7  are connected to each other by the high voltage cable  9 , the high voltage cable  9  is laid in a portion in the center in the vehicle width direction from the battery  8 , reaches the dash panel  2  through the upper surface of a fuel tank  10 , and is turned so as to rise along the dash panel  2  after passing through the dash panel  2 , and as a result, the high voltage cable  9  is connected to the inverter  15  in the mounting unit  7 . 
     A plurality of detail units configuring the mounting unit  7  are provided so as to be arranged in the vehicle width direction in front of the dash panel  2 . 
     For convenience, as shown in  FIG. 1 , the detail units configuring the mounting unit  7  comprises: an engine (referred also to as an “internal-combustion engine”)  11  configuring a power unit arranged on the right-hand side in the vehicle width direction of the engine compartment  3 ; a generator  12  being arranged on the left-hand side of the engine  11 , that is to say, near the center in the vehicle width direction; a driving motor (also described simply as a “motor”)  13  being arranged on the rear side in the vehicle front and rear direction of the generator  12  of the generator  12 ; and a gear case  14  being arranged on the rear side in the vehicle front and rear direction of the engine  11  and being arranged on the right-hand side, in the vehicle width direction, of the driving motor  13  to output a driving force which is input from the driving motor  13  toward the front wheels  5 . The inverter  15  is arranged on the left-hand side, in the vehicle width direction, of the generator  12  and the driving motor  13 . 
     The engine  11 , the generator  12 , the driving motor  13 , and the gear case  14  which are configured as detail units, are accommodated and mounted in the engine compartment  3 . 
     The drive and stop of the engine  11  can be changed over at optional timing during the running of the vehicle  1 . 
     The generator  12  is drivingly connected to the engine  11  mechanically. 
     The engine  11  and the generator  12  are formed as an integrated unit. 
     The driving motor generates a vehicle driving force. 
     The gear case  14  transmits power following the driving motor  13 . 
     The driving motor  13  and the gear case  14  are formed as an integrated unit. 
     These components constitute a true power unit for driving the vehicle  1 . 
     Here, the relationship between mounting positions of these parts is explained in detail. As shown in  FIG. 6 , the inverter  15  is arranged in an upper portion arranged inside of an engine hood  16  of the engine compartment  13 , and the inverter  15  is connected to the battery  8  in the high voltage energy system to control the driving motor  13 . 
     This inverter  15  is arranged and mounted so as to cover the upper sides of both of the generator  12  which is positioned on the front side in the vehicle front and rear direction, and the driving motor  13  which is positioned on the rear side of the generator  12 . 
     Above the engine  11 , accessories (not shown) of an intake system are disposed. 
     At the mounting time, all of these parts are assembled together with the mounting unit  7 , and are mounted collectively. 
     Although not shown in detail, as shown in  FIG. 6 , a radiator  17  for an engine cooling system, a radiator (not shown) for a generator or a driving motor cooling system, a condenser (not shown) for an air-conditioning system, and the like, are disposed in a front portion of the engine compartment  3 . In the lower portion of the engine compartment  3 , a motor-driven compressor (not shown) for the air-conditioning system, a water pump  18  for the generator or a driving motor cooling system, and the like, are disposed. 
     In this configuration, the generator or a driving motor cooling system is configured so as to cool the generator  12 , the driving motor  13 , and the inverter  15 . 
     The power unit that is to generate a vehicle driving force and is to transmit the driving force, is formed by the driving motor  13  and the gear case  14 . 
     Although not shown in the drawings, the driving force is transmitted from the gear case  14  to an axle shaft  19 . 
     While considering the balance, vibrations, and the like of the right and left driving shafts (not shown), the driving force is transmitted via an intermediate shaft (not shown) as necessary. 
     As shown in  FIGS. 6 and 7 , the driving motor  13  and the gear case  14  are fixed to the upper surface side of a subframe (not shown, also referred to as a “suspension frame”) of a vehicle body  21  via a rear mount  20  of which vibrations are isolated by an elastic member. 
     The engine  11  and the generator  12  do not generate the vehicle driving force directly, that is to say, it can be said that the engine  11  and the generator  12  do not configure the power unit. 
     The engine  11  and the generator  12  can generate the electric power for driving the power unit. 
     That is to say, the vehicle  1  is of a series-type hybrid driving system. 
     If the engine  11  and the generator  12  are omitted, the vehicle  1  becomes an electric vehicle in a narrow sense. 
     If specific conditions are met, for example, if the charge amount of the battery  8  decreases, the engine  11  and the generator  12  are used such that the engine  11  is started and driven to turn the generator  12 , and as a result, electric power is generated. 
     The engine  11  and the generator  12  are arranged such that their lengthwise directions are directed to the vehicle width direction, and as shown in  FIG. 7 , the engine  11  and the generator  12  are fixed to side frames  23  of the vehicle body  21  via mounts  22  at both of the right and left ends thereof. 
     As shown in  FIG. 7 , a crankshaft (not shown) of the engine  11  and a rotating shaft (not shown) of the generator  12  are positioned so as to be lower than a rotating shaft  24  of the driving motor  13 . This configuration contributes to keeping of the centers of gravity in the engine  11  and the generator  12  at lower positions. 
     The combination of the engine  11  and the generator  12 , and the combination of the driving motor  13  and the gear case  14 , are connected to each other so as to be mechanically integrated in a portion in which these combinations are closest to each other, and these combinations are mounted to the vehicle  1  via three mounts including the right and left mounts  22  and the rear mount  20 . 
     The combinations are usually supported stably by the mounts  20 ,  22 , and  22 . On the other hand, the combinations are configured such that if a load caused by an external force is applied from the front, the unit in which the combination of the engine  11  and the generator  12  and the combination of the driving motor  13  and the gear case  14  are integrated (for convenience, referred to as the “mounting unit  7 ”), can move almost horizontally toward the vehicle rear portion. 
     Although not shown in the drawings in detail, the rotating shaft  24  of the driving motor  13  is positioned so as to be higher than the crankshaft of the engine  11  and the rotating shaft of the generator  12  as shown in  FIG. 7 . 
     As a result, in plan view (also referred to as “bottom view”), the generator  12  and the driving motor  13  are arranged such that a casing (not shown) of the generator  12  and a casing (not shown) of the driving motor  13  overlap partially one on the other in the upper and lower direction. Therefore, the longitudinal length of the mounting unit  7  can be short, and furthermore, the movement dimension with respect to the mounting space of the vehicle body  21  can be made large. In particular, the dimension between the dash panel  2  and the casing of the driving motor  13  is made large. 
     The gear case  14  has an input shaft (not shown) coaxially with the rotating shaft  24  of the driving motor  13  in the upper portion thereof, and the gear case  14  has an output shaft (not shown) connecting with the axle shaft  19  in the lower portion thereof. 
     In the gear case  14 , a reduction gear (not shown) and a working device (not shown) are accommodated. 
     The external shape of the gear case  14  can be made so as to be relatively long in the upper and lower direction and short in the front and rear direction. 
     Under the driving motor  13 , the intermediate shaft is provided. 
     As shown in  FIG. 7 , an exhaust pipe  25  configuring the exhaust system of the engine  10 , runs under the engine  10 , forms two-stage crank-like bend portions  25   a  and  25   b,  and extends to the vehicle rear passing through a center tunnel  27  of the floor panel (also referred to as the “vehicle body floor”)  26 . 
     The exhaust pipe  25  takes a surrounding shape so as to go around the gear case  14  due to the two-stage crank-like bend portions  25   a  and  25   b.    
     In this configuration, by increasing the distance between the two-stage crank-like bend portions  25   a  and  25   b  of the exhaust pipe  25  and the gear case  14 , the influence of radiation heat can be reduced. 
     As shown in  FIGS. 4 and 5 , the high voltage cable  9  extends from one end of the battery  8  to the vehicle front portion above the floor panel  26 , is then bent to the vehicle center direction so as to extend along the periphery of the battery  8 , and extends again toward the vehicle front when reaching a portion near the center in the vehicle width direction. 
     In this configuration, as shown in  FIGS. 4 and 5 , the high voltage cable  9  extending toward the vehicle front is attached to the floor panel  26  by a protective cover  28  in a portion in rear of the dash panel  2 , that is to say, in a space portion having sufficient room. 
     As shown in  FIGS. 5 and 7 , in the portion of the protective cover  28 , since a steering attachment part  29  is formed near the right front wheel  5  of the vehicle  1 , the high voltage cable  9  is curved so as to go around the steering attachment part  29 . 
     In the vicinity of a portion in which the vehicle rear portion of the floor panel  26  rises from the vehicle front portion thereof, the high voltage cable  9  penetrates the floor panel  26  from the upper side of the floor panel  26  to the lower side thereof (refer to  FIG. 6 ), and furthermore the high voltage cable  9  extends to the vehicle front and rear direction along the lower surface of the vehicle front portion of the floor panel  26 . 
     On the lower surface of the vehicle front portion of the floor panel  26 , the high voltage cable  9  extends in the vehicle front and rear direction so as to run along the side frame  23  and the center tunnel  27  between these components. 
     At a position at which the vehicle front portion of the floor panel  26  connects with the dash panel  2 , the high voltage cable  9  partially enters into the end portion space of the center tunnel  27 , and then extends along the surface of the dash panel  2  which faces to the back surface of the gear case  14 . 
     A subframe is provided at a position under the dash panel  2 , and this position is also a position at which the rear mount  20  is provided. 
     In the internal space of the center tunnel  27 , and also in a space including a space held between the center tunnel  27  and the subframe, the high voltage cable  9  is arranged so as to avoid interference with a steering rack (not shown). 
     The high voltage cable  9  is laid so as to be separate from the exhaust pipe  25  to the opposite side in the vehicle width direction so that thermal expansion and interference in a narrow and limited space are avoided. 
     At the same time, the high voltage cable  9  extends from a high position above the internal space of the center tunnel  27  to the front of the front surface of the dash panel  2 , and as a result, a length range held between the dash panel  2  and the mounting unit  7  is decreased. Therefore, problems are prevented in that the high voltage cable  9  is held between the mounting unit  7  and the dash panel  2  when a space between these components is decreased by deformation. 
     That is to say, in the present invention, the detail units are provided such that the rear surfaces thereof are formed so as to produce a positional difference  30  in the vehicle front and rear direction, and are formed so as to make the distances from the dash panel  2  different, and the high voltage cable  9  is laid so as to run in a dash panel  2  portion facing to the rear surface of the detail unit on one side on which the distance from the dash panel  2  is greater than that on another side. 
     When describing more specifically, in the case in which the detail units are the engine  11 , the generator  12 , the driving motor  13 , and the gear case  14 , the positional difference  30  is made between the rear surfaces of the driving motor  13  and the gear case  14  which are positioned on the rear side in the vehicle front and rear direction. 
     In this case, the positional difference  30  is made such that the distance from the dash panel  2  to the rear surface of the gear case  14  is greater than the distance from the dash panel  2  to the rear surface of the casing of the driving motor  13 . 
     That is to say, referring to  FIG. 1 , when defining the distance between the rear surface of the driving motor  13  and the front surface of the dash panel  2  as S 1 , and defining the distance between the rear surface of the gear case  14  and the front surface of the dash panel  2  as S 2 , the relationship 
       S 1 &gt;S 2   
     is satisfied, and the positional difference  30  is made by the distances S 1  and S 2 . 
     A difference d (refer to the hatched portion in  FIG. 1 ) between the distance S 2  and the distance S 1 , which forms the positional difference  30 , is set at a dimension not less than the maximum external shape dimension of the high voltage cable  9 . 
     As shown in  FIGS. 1 and 2 , the high voltage cable  9  is laid so as to run in a dash panel  2  portion facing to the rear surface of the detail unit on one side on which the distance from the dash panel  2  is greater than that on another side, that is to say, the high voltage cable  9  is laid so as to run in the dash panel  2  portion facing to the rear surface of the gear case  14  having the distance S 2 . 
     By doing this, for example, at the front collision time at which an external force is applied from the vehicle front to the vehicle  1 , as shown in  FIG. 3 , the mounting unit  7  is moved to the vehicle rear portion, the distance S 1  is made zero, and the rear surface of the driving motor  13  of the mounting unit  7  is brought into contact with the front surface of the dash panel  2 . 
     At this time, the whole of the unitized mounting unit  7  comes into contact with the front surface of the dash panel  2 , as indicated by the hatched portion in  FIG. 3 , between the rear surface of the gear case  14  and the front surface of the dash panel  2  which faces the rear surface of the gear case  14 , and therefore, a gap formed by the difference d between the distance S 2  and the distance S 1  is formed. 
     Even in the case in which an external force stronger than that at the above-described front collision time is applied from the vehicle front of the vehicle  1 , the whole of the unitized mounting unit  7  retracts in the state in which a gap formed by the difference d between the distance S 2  and the distance S 1  is ensured between the rear surface of the gear case  14  and the front surface of the dash panel  2  which faces to the rear surface of the gear case  14 , and therefore, problems of disappearing gap are minimized. 
     Therefore, when the mounting unit  7  moves to the rear and comes into contact with the dash panel  2 , the gap is ensured by the positional difference  30 , and as a result, the high voltage cable  9  can be prevented from being damaged. Even in the case in which the contact does not occur, the space can be ensured, the interference can be avoided, and a work space can be maintained. Furthermore, a component, such as a strong sheet metal cover or resin protector for collision guard can be omitted or be simplified. 
     The detail units of the mounting unit  7  is formed by the driving motor  13  necessary as an electric vehicle and the gear case  14  necessary in association with the driving motor  13  so that the mounting unit  7  can be used for many types of vehicles. 
     Furthermore, the driving motor  13  having the outside diameter of a cylindrical shape due to the inclusion of a rotating body is used, and the gear case  14  having a high degree of freedom is accommodated in the casing having a shape of specific dimensions so that the mounting unit  7  can be used easily without the need for special and new techniques. 
     The casing of the driving motor  13  of the mounting unit  7  is provided so as to be positioned in the center portion in the vehicle width direction, and the gear case  14  is formed so as to be long in the upper and lower direction with the input shaft which is higher than the output shaft, and is formed so as to be short in the vehicle front and rear direction. Therefore, the rotating shaft  24  of the driving motor  13  is connected to the input shaft of the gear case  14 . 
     Therefore, the position of the driving motor  13  is high, and the driving motor  13  faces to the front surface of the dash panel  2 , so that when the mounting unit  7  moves to the rear, the mounting unit  7  can be reliably brought into contact with the front surface of the dash panel  2 , and a load can be received by the dash panel  2  stably and surely. 
     Furthermore, the dash panel  2  has an opening structure which is a start position of the center tunnel  27 , at a portion connecting with the floor panel  26 , and the rear surface of the casing of the driving motor  13  faces a portion near the upper portion of the opening structure. On the other hand, the high voltage cable  9  passes through the opening of the center tunnel  27  from a lower portion of the floor panel  26 , and is laid to the front surface of the dash panel  2  which faces to the rear surface of the gear case  14 . 
     Therefore, since the high voltage cable  9  is brought into contact with the highly rigid dash panel  2  by the center tunnel  27 , the high voltage cable  9  can withstand a load, and the gap formed by the positional difference  30  can be maintained. 
     For this reason, the high voltage cable  9  can be introduced from a high position of the opening, and as a result, the high voltage cable  9  can be prevented from being damaged. 
     The dimension of the range overlapping on the rear surface of the mounting unit  7  (in particular, the rear surface of the gear case  14 ) can be made short by the wiring of the high voltage cable  9 . Furthermore, since the high voltage cable  9  can be introduced from a high position of the opening into the engine compartment  3 , the range in which the protective member and the like are provided can be reduced. 
     The interference with the steering rack can be avoided. 
     The present invention is not limited to the above-described Embodiment, and various modifications and changes can be made. 
     For example, in the Embodiment of the present invention, explanation has been given of the series-type hybrid electric vehicle. However, if the arrangement is made such that the casing of the driving motor for generating the driving force of vehicle and the gear case formed by a reduction gear are mounted in a space in front of the dash panel in the same way as in this Embodiment, the present invention may be applied to a pure electric vehicle and a hybrid electric vehicle having any other driving system (for example, a parallel system or a split system). 
     Furthermore, the combination of the engine and the generator, and the combination of the driving gear and the gear case can be mounted in a compact manner by unitization. However, since the driving force is not transmitted therebetween, these combinations need not necessarily be connected mechanically. 
     That is to say, the mounting unit may be formed by the driving motor and the gear case. 
     REFERENCE NUMERALS 
     
         
           1  Vehicle 
           2  Dash panel 
           3  Engine compartment 
           7  Mounting unit 
           8  Battery 
           9  High voltage cable 
           10  Fuel tank 
           11  Engine 
           12  Generator 
           13   13  Driving motor 
           14  Gear case 
           15  Inverter 
           23  Side frame 
           24  Rotating shaft of driving motor 
           25  Exhaust pipe 
           26  Floor panel (referred also to as “vehicle body floor”) 
           27  Center tunnel 
           28  Protective cover 
           29  Steering attachment part 
           30  Positional difference 
         S 1  Distance between rear surface of driving motor and front surface of dash panel 
         S 2  Distance between rear surface of gear case and front surface of dash panel 
         d Difference between distance S 2  and distance S 1