JP2015131577A - Onboard structure of invertor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for mounting an invertor that controls a rear motor for driving a rear wheel on a rear part of a vehicle with good space efficiency.SOLUTION: A recess 22 for housing a spare tire which is provided at a floor panel 25 below a luggage space is utilized. An invertor 12 is installed in a posture inclining backward so that a vehicle front side of the invertor 12 is higher than a rear side, at a position higher than a bottom surface of the recess 22 while closer to the front side of a vehicle than a center CL of the recess 22. By this configuration, even if water accumulates in the recess 22, the invertor 12 is prevented from being flooded.

Description

  The technology disclosed in this specification relates to an in-vehicle structure of an inverter that controls a rear motor for driving rear wheels of an electric vehicle. The “electric vehicle” in the present specification includes an electric vehicle and a hybrid vehicle and a fuel cell vehicle including both a motor and an engine.

  Four-wheel drive electric vehicles equipped with motors before and after the vehicle are being studied. For example, Patent Document 1 discloses a hybrid vehicle in which a hybrid system including an engine and a motor as a front wheel drive source is mounted on the front side of the vehicle, and another motor is mounted on the rear side of the vehicle as a rear wheel drive source. .

JP 2005-323455 A

  As an aspect of a four-wheel drive electric vehicle, an aspect in which a motor (and an engine) provided in front of the vehicle is used for normal travel and a rear motor is used as an auxiliary drive source can be considered. Further, as an electric vehicle, a front wheel drive vehicle including a motor (or a hybrid drive source of a motor and an engine) in front of the vehicle is widely used. Therefore, if a four-wheel drive electric vehicle is designed based on such a front-wheel drive electric vehicle, existing parts can be used, and a four-wheel drive electric vehicle can be realized at low cost.

  A four-wheel drive vehicle based on a front-wheel drive electric vehicle has a front-wheel drive motor (hereinafter referred to as front motor) and an inverter that controls the motor (hereinafter referred to as front inverter), as well as a rear-wheel drive motor (hereinafter referred to as front-wheel drive motor). , A rear motor) and an inverter for controlling the motor (hereinafter referred to as a rear inverter). The rear motor and the rear inverter are mounted on the rear side of the vehicle. On the other hand, the front-wheel drive vehicle has a luggage space at the rear of the vehicle. To realize a low-cost four-wheel drive vehicle based on a front-wheel drive vehicle, a rear motor and a rear inverter are mounted on the rear of the vehicle. However, if the rear motor and the rear inverter are simply mounted on the rear of the vehicle, a load is loaded. Luggage space to be narrowed.

  The present specification relates to a mounting structure of a rear inverter. The technology disclosed in the present specification provides a space-efficient rear inverter mounting structure.

  In the case of a front wheel drive vehicle, a space for accommodating a spare tire is usually secured below the luggage space. On the other hand, in recent years, with the spread of run-flat tires and excellent puncture repair kits, the situation where spare tires need not be used has been established. Accordingly, the inventors of the present application have come up with the idea of effectively utilizing the spare tire storage space. The spare tire storage space is located below the luggage space, and a recess corresponding to the shape of the spare tire is provided at the bottom of the storage space. The spare tire is fixed in this recess. However, this depression has a low ground clearance, and the drainage hole is small for countermeasures against mud splash and gravel splash, and the drainage is not high. Therefore, if water enters the luggage space, there is a risk that water may temporarily accumulate in the spare tire storage space. It is not preferable that the inverter is immersed in water. The inventor has created a structure in which a part of the inverter is accommodated in the recess of the spare tire accommodation space as much as possible so that the inverter is not immersed even if some water accumulates in the spare tire accommodation space. Hereinafter, for the convenience of explanation, the recess for the spare tire provided at the bottom of the space for storing the spare tire is referred to as a tire fixing recess. In addition, the bottom of the storage space for the spare tire is composed of a floor panel. Therefore, the tire fixing recess is provided in the floor panel.

  The mounting structure of the rear inverter disclosed in this specification is that the rear inverter is installed in the tire fixing recess. At that time, the rear inverter is placed at a position higher on the vehicle front side than the center and higher than the bottom surface of the tire fixing recess. Install the inverter in a leaning posture so that the front side of the vehicle is higher than the rear side. In this in-vehicle structure, the height from the bottom surface of the tire fixing recess is lowest at the rear end of the rear inverter lower surface. The height is set to a water surface height that is likely to occur when water accumulates in the tire fixing recess. On the other hand, when the posture of the vehicle body is lowered forward due to a downhill or the like, the bottom surface of the tire fixing recess is also lowered forward, and the water depth in front of the tire fixing recess is deepened. However, the rear inverter is installed in a backward inclined posture, and the height from the bottom surface of the tire fixing recess to the front end of the lower surface is higher than the height at the rear surface rear end. Therefore, even if the vehicle body is lowered forward, the inverter is not immersed in water. On the other hand, by installing the rear inverter in the tire fixing recess in a rearward tilt posture, the space above the rear inverter, that is, the luggage space can be used effectively. The above-described on-vehicle structure skillfully utilizes the tire accommodation space when the rear inverter is mounted on the rear part of the vehicle, and secures as large a luggage space as possible.

  Note that the size (length or width) of the rear inverter that drives the rear motor is generally less than or equal to the radius of the tire fixing recess. Therefore, the tire fixing recess has a size that is just right for installing the rear inverter in the space in the front half thereof. The difference in size between the rear inverter and the tire fixing recess is also one of the points of sight that led to the present invention.

  For example, the above-described in-vehicle structure utilizes the fact that the upper edge of the rear of the tire fixing recess is lower than the upper edge of the front of the vehicle in many automobiles. In that case, when the water is most accumulated in the tire fixing recess, the water surface becomes the same height as the upper edge of the tire fixing recess behind the vehicle (when the vehicle body is horizontal). If the height from the bottom surface of the tire fixing recess to the rear lower end of the rear inverter is set to the same height as the upper edge at the rear of the vehicle of the tire fixing recess, the rear inverter can be prevented from being immersed in water.

  Since the rear inverter generates heat, a radiating fin may be provided in the casing. The fins may be submerged in water. Further, in the mounting structure described above, the rear inverter is installed in a backward tilting posture, so there is room in the space below the front side of the lower surface. This margin is secured to prevent the rear inverter from being immersed in water even if the vehicle body tilts forward and water accumulates in front of the tire fixing recess. As described above, since the fins may be immersed in water, it is preferable to provide the fins in front of the lower surface of the rear inverter. The space under the luggage luggage space can be used more effectively. In addition, when attaching the fan which ventilates to a fin to the housing | casing of a rear inverter, a fan is attached to a position higher than the assumed water surface.

  According to the technology disclosed in this specification, when a four-wheel drive electric vehicle is realized based on a front-wheel drive electric vehicle, a rear inverter is mounted using the existing space of the base electric vehicle, As much luggage space as possible can be secured. Details and further improvements of the technology disclosed in this specification will be described in the following “DETAILED DESCRIPTION”.

It is a block diagram of the electric power system of the electric vehicle of an Example. It is a typical layout figure of an inverter and a battery when the electric vehicle of an Example is seen from the side. It is a typical side view of the inverter mounted in the tire accommodation hollow of the back luggage space of the electric vehicle of an Example. It is the figure which showed the relationship between the water surface which the inverter mounted in the tire accommodation hollow of the rear luggage space of the electric vehicle of an Example, and the water stored in a tire accommodation depression. It is a figure which shows the other Example in the mounting structure of the inverter mounted in the back luggage space of an electric vehicle. It is a figure which shows the further another Example in the mounting structure of the inverter mounted in the back luggage space of an electric vehicle.

  An electric vehicle (hybrid vehicle 200) according to an embodiment will be described with reference to the drawings. As shown in FIG. 1, the hybrid vehicle 200 includes a front motor 3 and an engine 4 that are three-phase AC motors for driving the front wheels 7. Output torques from the front motor 3 and the engine 4 are combined by the power distribution mechanism 5 and transmitted to the front wheels 7 via the differential gear 6. The power distribution mechanism 5 may distribute the output torque of the engine 4 to the front wheels 7 and the front motor 3. In that case, the hybrid vehicle 200 generates power with the front motor 3 while traveling with the power of the engine 4. The generated power is charged in a battery 16 described later.

  The hybrid vehicle 200 includes a rear motor 9 that is a three-phase AC motor for driving the rear wheel 13. The rear motor 9 is an auxiliary drive source and has a smaller output than the front motor 3 that is the main drive source. For example, the maximum output of the front motor 3 is 50 kW, and the maximum output of the rear motor 9 is 5 kW. The hybrid vehicle 200 normally travels with the engine 4 and the front motor 3, and auxiliaryly drives the rear motor 9 as necessary. For example, when it is slippery on a snowy road, the rear motor 9 is driven and the vehicle travels by four-wheel drive. Alternatively, the rear motor 9 is driven to assist torque when starting on a slope. The rear motor 9 and a rear inverter 12 described later are attached as optional equipment of the two-wheel drive hybrid vehicle 200 according to the user's request.

  The electric power stored in the battery 16 is converted from DC power to AC power by the front inverter 2 and supplied to the front motor 3. The front inverter 2 has a built-in voltage converter circuit that boosts the voltage of DC power together with an inverter circuit that converts DC power into AC power. Note that the voltage converter circuit may function as a step-down circuit for stepping down the regenerative power from the front motor 3 and charging the battery 16. Further, the power stored in the battery 16 is converted from DC power to AC power by the rear inverter 12 and supplied to the rear motor 9. The rear motor 9 has a smaller output than the front motor 3, and its rated voltage is equal to the output voltage of the battery 16. Therefore, unlike the front inverter 2, the rear inverter 12 does not include a voltage converter circuit. The front inverter 2 and the rear inverter 12 are connected to the power control unit 17 and are centrally controlled according to the traveling state of the hybrid vehicle 200. Further, the front inverter 2 and the rear inverter 12 are connected in parallel with the battery 16 by a relay 15. The front inverter 2 and the rear inverter 12 are connected to the battery 16 by a repeater 15 and power cables 8 and 14, respectively.

  The layout of the front inverter 2 and the rear inverter 12 of the hybrid vehicle 200 will be described. FIG. 2 is a view of the hybrid vehicle 200 as viewed from the lateral direction of the vehicle, and is a cross-sectional view along the approximate center of the lateral direction of the vehicle. The outer shell of the vehicle, the front seat 32a, and the rear seat 32b are drawn with a two-dot chain line in consideration of easy viewing of the drawings. It should be noted that details of the cross sections of the inverters 2 and 12 and the battery 16 are omitted and drawn in hatching. As shown in FIG. 2, the front inverter 2 is disposed in the front of the vehicle, and the rear inverter 12 is disposed in the rear of the vehicle. The front inverter 2 is installed in a front compartment in front of the vehicle. In FIG. 2, a detailed view of the front compartment is omitted. Further, although the front motor 3, the engine 4, and the power distribution mechanism 5 are installed in the front compartment, it should be noted that the illustration is omitted in FIG. The illustration of the rear motor 9 is also omitted.

  The rear inverter 12 is disposed below the luggage space 31 behind the rear seat 32b (vehicle rear). Below the luggage space 31, a spare tire storage space (hereinafter referred to as a storage space 21) surrounded by the floor panel 25 and the deck board 23 that becomes the floor of the luggage space 31 is provided. The floor panel 25 which is the bottom of the accommodation space 21 is provided with a recess (hereinafter referred to as a tire accommodation recess 22) according to the shape of the spare tire. Normally, the spare tire is fixed by being fitted into the tire housing recess 22.

  In the embodiment, a four-wheel drive hybrid vehicle 200 is realized by mounting the rear motor 9 on the basis of a widespread front-wheel drive hybrid vehicle. As shown in FIG. 2, conventionally, a spare tire 24 drawn by a two-dot chain line has been installed along the tire housing recess 22. However, in the present invention, the rear inverter 12 is installed in the tire housing recess 22 instead of the spare tire 24. By installing the rear inverter 12 in the tire housing recess 22 at the rear of the vehicle, the length of the power cable connecting the rear motor 9 and the rear inverter 12 can be shortened, and loss during power transmission can be suppressed.

  The battery 16 is disposed on the upper surface of the floor panel 25 below the rear seat 32b. Electric power from the battery 16 is supplied to the front inverter 2 and the rear inverter 12 by the relay 15. Power cables 8 and 14 connect the repeater 15 to the front inverter 2 and the rear inverter 12. The power cables 8 and 14 are simplified in FIG. 2 and drawn with thick lines. It should be noted that the layout of the power cables 8 and 14 is also simplified in FIG.

  The mounting structure of the rear inverter 12 will be described. FIG. 3 shows an enlarged view of the accommodation space 21 in FIG. As shown in FIG. 3, the rear inverter 12 is housed in the housing space 21. A tire housing recess 22 is provided in the floor panel 25 at the bottom of the housing space 21. An upper edge 22b (hereinafter referred to as a rear upper edge 22b) on the vehicle rear side of the tire housing recess 22 is located below the vehicle on an upper edge 22a (hereinafter referred to as a front upper edge 22a) on the vehicle front side. The length of the rear inverter 12 in the vehicle front-rear direction is shorter than the length of the tire housing recess 22 in the same direction, and the length in the vehicle lateral direction is also shorter in the rear inverter 12 than the tire housing recess 22. The rear inverter 12 includes an inverter main body 12a and a flat plate-shaped flange 12b provided on the lower surface of the inverter main body 12a. The flange 12b extends in the vehicle longitudinal direction of the inverter body 12a. The vehicle front side of the flange 12b is fixed by a bolt 29 to a front side fixing portion 26 provided on the surface 25a of the floor panel 25 adjacent to the front upper edge 22a of the tire housing recess 22. On the other hand, the vehicle rear side of the flange 12b is fixed to the upper surface of the projecting portion 27 projecting upward from the bottom surface of the tire housing recess 22 with a bolt 29. That is, the rear inverter 12 is installed so as to straddle between the front side fixing portion 26 and the protruding portion 27. The protrusion 27 is provided on the front side of the vehicle with respect to the center line CL in the vehicle front-rear direction of the tire housing recess 22. Therefore, the rear inverter 12 is located on the vehicle front side with respect to the center line CL of the tire housing recess 22. Moreover, the height of the protrusion 27 is higher than the rear upper edge 22b of the tire housing recess 22 and lower than the front upper edge 22a. Therefore, the rear inverter 12 is fixed to the front side fixing portion 26 and the protruding portion 27 so that the vehicle front side of the rear inverter 12 is higher than the rear side. In other words, the rear inverter 12 is installed in a backward inclined posture at a position higher than the bottom surface of the tire housing recess 22.

  Further, below the rear inverter 12, there is a space 18 surrounded by the lower surface of the flange 12 b, the tire housing recess 22, and the protruding portion 27. Radiating fins 28 are provided on the lower surface of the rear inverter 12 (the lower surface of the flange 12b). The radiating fins 28 are located in the space 18 toward the lower side of the vehicle. The radiation fins 28 have a structure in which flat plates of a material having high thermal conductivity (for example, aluminum) are arranged in a row in a comb shape. With this structure, the surface area of the lower surface of the rear inverter 12 can be increased, and the contact area with air in the rear inverter 12 can be increased. Therefore, the heat dissipation efficiency of the rear inverter 12 can be increased.

  The positional relationship between the water surface and the rear inverter 12 when water accumulates in the tire housing recess 22 will be described. As shown in FIG. 4, when the posture of the vehicle body is horizontal, the water level of water accumulated in the tire housing recess 22 is WL1 at the maximum. WL1 has the same height as the rear upper edge 22b of the tire recess 22. The height of the protruding portion 27 is higher than WL1, and the height of the front side fixing portion 26 is also higher than WL1. Therefore, the rear inverter 12 is not flooded. Further, the water surface when the posture of the vehicle body is lowered forward is WL2. This water surface WL2 represents the water surface when the posture of the vehicle body is lowered forward in a state where water of the same amount as the water surface WL1 is accumulated when the posture of the vehicle body is horizontal. Here, the angle at which the posture of the vehicle body is lowered forward is determined as a design value according to the legal standard of the road gradient on which the hybrid vehicle 200 travels. In the embodiment, the downward angle is about 10 degrees. As shown in FIG. 4, the rear inverter 12 is located above the water surface WL <b> 2, and the rear inverter 12 will not be submerged even when the posture of the vehicle body is lowered forward. In addition, about 10 degrees of the downward angle is about 17.6% when converted into a road gradient, and this value is larger than the maximum gradient of Japanese roads. That is, if the inverter is tilted backward by about 10 degrees, the lower front side of the inverter does not fall below the lower rear side even if the vehicle travels on a downward slope. If the rear inverter is tilted backward by about 10 degrees or more, the possibility that the rear inverter is immersed in water can be reduced even if water accumulates in the tire housing recess 22.

  Further, when the posture of the vehicle body is lowered downward, the water moves to the rear of the vehicle from the rear upper edge 22b. Further, the water depth in this case is lower on the vehicle front side and higher on the vehicle rear side. That is, the water surface in this case is further away from the rear inverter 12 than in the case where the posture of the vehicle body is horizontal. Therefore, the rear inverter 12 is not flooded.

  According to such a configuration, the rear inverter 12 is not positioned below the water surface (WL1, WL2) that can be assumed in design, and the rear inverter 12 can be prevented from being flooded. Further, the rear inverter 12 is installed in a backward tilting posture. For this reason, the space on the vehicle rear side above the rear inverter 12 can be widened. Therefore, the space can be effectively utilized, the deck board 23 can be lowered below the vehicle layout as shown in the drawing, and the luggage space can be widened.

  The heat radiation fin 28 is located in the space 18 on the lower surface of the inverter 12. And the radiation fin 28 is located in the vehicle front side. Since the space 18 is wider on the front side of the vehicle, the space around the heat dissipating fins 28 has good air circulation. Therefore, the cooling efficiency of the radiation fin 28 can be utilized to the maximum extent. Although not shown in the drawing, a fan for blowing air to the heat radiating fins 28 may be separately provided. By providing the fan, the air circulation can be further increased and the cooling efficiency of the radiating fins 28 can be increased. In addition, although it repeats, the fin provided separately is attached in a position higher than the assumed water surface (WL1, WL2).

  Further, as well shown in FIG. 2, the rear inverter 12 is installed at a position far from the rear side of the vehicle body outline in the tire housing recess 22. Therefore, the rear inverter 12 can be preferentially protected even when a collision is caused from the rear of the vehicle body.

  Another embodiment of the mounting structure of the rear inverter 12 will be described. As shown in FIG. 5, the vehicle front side of the flange 12 b of the rear inverter 12 may be fixed to a side surface fixing portion 32 provided on the side surface 22 c on the vehicle front side of the tire housing recess 22. The configuration other than the side fixing portion 32 is the same as that in the above-described embodiment.

  Further, as shown in FIG. 6, a protrusion 33 a with which the rear end of the flange 12 b abuts may be provided on the upper surface of the protrusion 33. According to this configuration, when the rear inverter 12 is attached to the protruding portion 33, the rear inverter 12 can be easily positioned in the vehicle front-rear direction by the rear end of the flange 12b and the protrusion 33a. This is because the rear inverter 12 is mounted in a tilted posture, so that the rear inverter 12 slides in the direction of gravity by the action of gravity and hits the protrusion 33a. Therefore, the assembling property by the operator can be improved. Although not shown in the drawing, the protrusion 33a may be provided at a position where the side end of the flange 12b on the vehicle rear side hits. According to this configuration, the rear inverter 12 can be positioned in the vehicle lateral direction, and the assemblability can be further improved.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2: Front inverter 3: Front motor 4: Engine 5: Power distribution mechanism 6: Differential 7: Front wheel 8, 14: Power cable 9: Rear motor 12: Rear inverter 13: Rear wheel 15: Repeater 16: Battery 17: Power control Unit 17
21: Storage space 22: Tire storage recess 23: Deck board 24: Spare tire 25: Floor panel 26: Front side fixing parts 27, 31, 33: Protrusion part 28: Radiation fin 32: Side surface fixing part CL: Center line WL1: Water surface (Body posture horizontal)
WL2: Water surface (lowering the body posture)

Claims (4)

An in-vehicle structure of an inverter that controls a rear motor for driving a rear wheel of an electric vehicle,
There is a recess for storing spare tires in the floor panel of the rear luggage space of the vehicle,
The inverter is installed in a tilted posture at a position on the vehicle front side from the center of the recess and higher than the bottom surface of the recess so that the vehicle front side of the inverter is higher than the rear side. In-vehicle structure of the inverter.   The in-vehicle structure for an inverter according to claim 1, wherein an upper edge on the rear side of the vehicle is located below the upper edge on the vehicle front side of the depression.   The in-vehicle structure of the inverter according to claim 1, wherein the heat dissipating fins of the inverter are arranged on the vehicle front side of the lower surface of the inverter.   The electric vehicle includes a front motor that drives front wheels in a front compartment of the vehicle, and the maximum output of the rear motor is smaller than the maximum output of the front motor. In-vehicle structure of the described inverter.

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