Vehicle equipment mounting structure

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

CROSS REFERENCE TO RELATED APPLICATION

This is a national phase application based on the PCT International Patent Application No. PCT/IB2012/000185 filed on Feb. 2, 2012, claiming priority to Japanese Patent Application No. 2011-021314 filed on Feb. 3, 2011, the entire contents of both of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a vehicle equipment mounting structure that arranges a motor case, in which a rotary electric machine that drives a vehicle is housed, in a compartment provided forward of a vehicle cabin, and that mounts a power control apparatus that controls the rotary electric machine, and an auxiliary battery that supplies electric power to a control portion of the power control apparatus.

2. Description of Related Art

Electric vehicles in which the vehicle is driven by driving force from a rotary electric machine such as a motor-generator, hybrid vehicles in which the vehicle is driven by a combination of a rotary electric machine and an engine that is an internal combustion engine, and fuel cell vehicles in which the vehicle is driven by electric power generated by a fuel cell, and the like are known. These kinds of vehicles are equipped with a power control apparatus that receives a supply of electric power from a main battery or a fuel cell, and has a step up converter and inverter and the like that control the electric power to a motor-generator (hereinafter, also referred to as “motor”).

The power control apparatus is also referred to as a PCU (power control unit), and must be mounted in an engine compartment that is close to the motor-generator in order to handle the high voltage and high current. Therefore, in a hybrid vehicle in which the engine is started by the motor-generator, an auxiliary battery for starting the engine is arranged in the luggage compartment because it does not need to be arranged near the engine, as well as for reasons related to space in the engine compartment. In recent years, high-voltage equipment is being made smaller and smaller, so the auxiliary battery is now able to be arranged inside the engine compartment and near the power control apparatus. As a result, a cable that had to be brought around to the luggage compartment can be reduced, thereby enabling both weight and cost to be reduced.

However, when the auxiliary battery is arranged near the power control apparatus, it is preferable to avoid interference between the auxiliary battery and power control apparatus in order to quickly and efficiently protect and rapidly discharge the power control apparatus when the vehicle is involved in a collision. Also, although there would be little harm from damage to the auxiliary battery because it is a relatively low voltage of only 12 volts, it is desirable to keep damage to the electric power apparatus that controls high voltage of several hundred volts to a minimum.

Therefore, technology described in Japanese Patent Application Publication No. 2002-362254 (JP-A-2002-362254) has a detachable mechanism in which, when the vehicle is involved in a collision, a relay box moves upward and detaches from a vehicle body in response to a load transmitted from an auxiliary battery via a guide surface when the auxiliary battery moves to the rear as a result of a barrier (i.e., an obstacle) penetrating the vehicle. The battery moves smoothly toward the rear by this mechanism. Providing this kind of detachable structure for the relay box makes it possible to improve the impact absorption performance by preventing interference between vehicle equipment and other members that move by the impact of a collision. Japanese Patent Application Publication No. 2010-158991 (JP-A-2010-158991) describes an equipment mounting structure that mounts a front end of a power control apparatus in a position farther back toward the rear of the vehicle than a front end of a motor case, and that arranges an electric compressor on the vehicle rear side of the power control apparatus, in order to protect the power control apparatus itself when the vehicle is involved in a collision.

With the structure described in JP-A-2002-362254 and JP-A-2010-158991, the auxiliary battery is able to be mounted using the space created in front of the motor case, by arranging the detachable structure and the power control apparatus in a location farther back on the motor case toward the rear of the vehicle. However, with a structure in which the auxiliary battery is arranged in front of the motor case, it is necessary to provide a detachable structure that safely moves the power control apparatus that is positioned to the vehicle rear of the auxiliary battery in order to protect and enable rapid discharge of the power control apparatus when the vehicle is involved in an collision, which leads to an increase in cost.

SUMMARY OF THE INVENTION

The invention thus provides a vehicle equipment mounting structure that moves an auxiliary battery toward the rear past a power control apparatus, without the auxiliary battery that is arranged near the power control apparatus interfering with the power control apparatus when there is a collision.

On aspect of the invention thus relates to a vehicle equipment mounting structure. This vehicle equipment mounting structure arranges a motor case, in which a rotary electric machine that drives a vehicle is housed, in a compartment provided forward of a vehicle cabin, and mounts a power control apparatus that controls the rotary electric machine, and an auxiliary battery that supplies electric power to a control portion of the power control apparatus. This vehicle equipment mounting structure has a fixing portion that fixes the power control apparatus onto the motor case, and a connecting portion that connects the auxiliary battery to a vehicle frame member that absorbs an impact load by being crushed in a crushing direction. The connecting portion includes a displaceable member that is displaceable in the crushing direction. The auxiliary battery is arranged on a vehicle front side of the power control apparatus such that the power control apparatus and the auxiliary battery partially overlap in the crushing direction, and the auxiliary battery is arranged so as to be able to move past the power control apparatus in response to the impact load.

Also, in the vehicle equipment mounting structure according to this aspect of the invention, the connecting portion may connect the auxiliary battery to the vehicle frame structure such that a front end portion of the auxiliary battery is farther toward the vehicle front side than a front end portion of the power control apparatus is. With this kind of arrangement, the auxiliary battery will absorb the impact before the power control apparatus does, so damage to the power control apparatus can be reduced.

A portion of the auxiliary battery may be arranged by the connecting portion so as to be positioned next to a side of the power control apparatus. With this kind of arrangement, the auxiliary battery is able to move without losing its posture, by being guided to the side of the power control apparatus.

Also, the connecting portion may be able to move in the crushing direction by displacement of the displaceable member, and may move the auxiliary battery without inhibiting the vehicle frame member from being crushed by the impact load. In this way, the connecting portion is able to move the auxiliary battery by displacement due to crushing of the vehicle frame member and the displacement of the connecting portion itself.

Also, the connecting portion may be connected to the vehicle frame member by the displaceable member in at least two locations. Because the auxiliary battery is connected to the displaceable member of the connecting portion, the vehicle frame member is not inhibited from being crushed.

The power control apparatus and the auxiliary battery may be arranged in this order from a center in a vehicle width direction toward an outside in the vehicle width direction. With this kind of arrangement, when there is an offset collision, the auxiliary battery absorbs the impact before the power control apparatus does, so damage to the power control apparatus can be reduced.

Furthermore, the motor case may be a double axis type transaxle with two rotary electric machines. The double axis type transaxle has a predetermined dimension in the vehicle longitudinal direction, so the power control apparatus is easily mounted on the transaxle.

Using the vehicle equipment mounting structure according to the aspect of the invention enables the power control apparatus to be arranged on the motor case, and the auxiliary battery to be arranged on a side member of a vehicle frame member so that it partially overlaps in the vehicle longitudinal direction with the power control apparatus. This mounting structure enables the space in the engine compartment to be utilized. Also, when there is a collision, a barrier penetrates the engine compartment while crushing the vehicle frame member and the support of the auxiliary battery. Consequently, the auxiliary battery moves past the power control apparatus such that the auxiliary battery does not interfere with the power control apparatus. As a result, the power control apparatus is able to be protected and can be rapidly discharged.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, example embodiments of the invention will be described in detail with reference to the accompanying drawings.

FIG. 1is a view of an engine compartment20of a hybrid vehicle10, and a vehicle equipment mounting structure for a PCU13that is arranged on an upper surface of a motor case12, and an auxiliary battery14. The structure of the engine compartment20will briefly be described with reference toFIG. 1. In the engine compartment20are provided a side member15that is provided on both sides of the hybrid vehicle10and is a vehicle frame member, a spring support16that is connected to the side member15, a front bumper reinforcement18that is connected to tip ends of the side member15, an engine11, the motor case12that is connected to the engine11, a wheel axle25that extends from the motor case12, the PCU13that is fixed onto the motor case12, the auxiliary battery14that is fixed by a fixture22, a mounting base21, and a support23onto the side member15, and a radiator17that is attached to a front portion. Here, the PCU13is fixed by a bolt to the motor case12, while the auxiliary battery14is configured to be able to move along the side member15in response to an impact load.

One characteristic of the vehicle equipment mounting structure according to this example embodiment is that the auxiliary battery14is connected to the side member15in such a way that a front end portion of the auxiliary battery14is farther toward a vehicle front side than a front end portion of the PCU13is. This kind of arrangement enables the PCU to be protected. Another characteristic is that the advancing direction of the auxiliary battery14that is smaller than the PCU13is defined by the fact that a side surface of the auxiliary battery14partially overlaps with a side surface of the PCU13. Yet another characteristic is that the auxiliary battery14is configured to protect the PCU13by moving past it when an impact load is applied, by a portion of the auxiliary battery14being arranged next to a side of the PCU13. In order to create this kind of configuration, in this example embodiment, innovations have been applied to both the mounting position of the auxiliary battery14and the support structure of the auxiliary battery14.

FIG. 2is a side view ofFIG. 1, and shows the vehicle equipment mounting structure of the PCU13arranged on the upper surface of the motor case12, and the auxiliary battery14. The description related to the structure described with reference toFIG. 1will be omitted. The auxiliary battery14is fixed onto the side member15by the support23that is fixed to the side member15, the mounting base21that is mounted on top of the support23, the fixture22that fixes the upper portion of the auxiliary battery14, and a J-bolt24that fixes the fixture22to the support23. The position in which the auxiliary battery14is fixed is farther toward the front of the vehicle than the PCU13by a distance that takes crush displacement length into account. As the crush displacement length, a distance is set at which a collision load can be sufficiently absorbed in conjunction with the crush displacement of the front bumper reinforcement18, in response to the support23being crushed toward the rear of the vehicle without inhibiting the side member15from being crushed, when an impact load is applied.

FIG. 3is a view of a frontal offset collision in which a barrier has penetrated the engine compartment20shown inFIG. 1, andFIG. 4is a side view of the state shown inFIG. 3. As a result of the barrier penetrating the right half of the vehicle following an impact load, the front bumper reinforcement18and the radiator17are crushed first, and then the side member15, a front apron, and the support23of the auxiliary battery are crushed. Then the barrier collides with the engine11or the motor case12. As a result of this deformation and collision, the auxiliary battery14moves along the side of the PCU13to substantially the same position as the PCU13, and as a result, a collision between the PCU13and the auxiliary battery14is able to be avoided. From this kind of sequential crushing, the impact load is able to be absorbed by the engine compartment20and the mounting equipment, so the PCU13can be protected and rapidly discharged. Next, the fixing structure of the auxiliary battery14will be described in detail.

FIG. 5is a perspective view of the auxiliary battery14shown inFIG. 4. The auxiliary battery14is mounted on top of the support23that is fixed to a side member. The fixture22that fixes the auxiliary battery14is provided on the upper surface of the auxiliary battery14. The fixture22is connected to the support23by two J-bolts24and nuts31. The auxiliary battery14is fixed via the mounting base21on top of the support23by the fixture22and the two J-bolts24and nuts31. Here, the support23has a structure that has the necessary strength in the vertical direction to support the weight of the auxiliary battery14, but that will not inhibit the side member15from being crushed in the crushing direction. The fixture22and the two J-bolts24that hold the top surface of the auxiliary battery14have a structure that moves parallel to the crushing direction in response to deformation of the support23and deformation of the side member15. Next, the structure of the support23will be described in detail.

FIG. 6is a perspective view of the support23that supports the auxiliary battery shown inFIG. 5. The support23is fixed to the side surfaces of the side member15by fixing portions33in four locations. The support23is formed by press-forming a thin plate, and includes an expanding and contracting portion that expands and contracts such that a parallelogram is crushed in the longitudinal and parallel direction as the side member15is crushed when a collision load indicated by the large arrow in the drawing is applied, and an inhibiting portion32that is provided at opposing corners of the parallelogram so as to inhibit expansion and contraction of the expanding and contracting portion up to a predetermined load. The inhibiting portion32is designed to maintain the strength of the support23. Vibration control and strength are able to be maintained by the inhibiting portion32. Moreover, the inhibiting portion32allows the expanding and contracting portion to deform by being drawn out by a tensile load from an impact load and deforming until it breaks. At this time, the relative position of the J-bolts24that are retained by J-bolt retaining portions35moves in the crushing direction by the deformation of the expanding and contracting portion, and the J-bolts24on the opposite side move, sliding on a J-bolt moving portion36, such that the auxiliary battery14moves in the crushing direction. In this way, the auxiliary battery14is able to move past the side of the PCU13by moving parallel to the crushing direction, without the orientation of the auxiliary battery14changing. Next, an example embodiment in which an auxiliary battery is arranged straddling a side member will be described in detail.

FIG. 7Ais a perspective view of a support26that supports an auxiliary battery according to another example embodiment of the invention.FIG. 7Bis a view of deformation of the support26when an impact load is applied. The support26shown inFIG. 7Ais fixed straddling a side member15by fixing portions34at four locations, by four leg portions27and28, a mounting surface29that is supported by the leg portions, and J-bolt retaining portions35and37formed on the mounting surface. Therefore, a protruding press-formed portion37is provided on each of the four leg portions such that the support26will crush relatively easily in the crushing direction when an impact load is applied. As a result, vibration control and strength are able to be maintained. With this kind of shape, the bent portions deform and the parallelogram expands and contracts in the longitudinal and vertical directions when an impact load is applied, as shown inFIG. 7B, thereby enabling the auxiliary battery to move in the crushing direction without changing the orientation of the auxiliary battery.

As described above, using the vehicle equipment mounting structure according to the example embodiment makes it possible to utilize the space in the engine compartment by having the power control apparatus arranged on the motor case, and have the auxiliary battery arranged on a side member of a vehicle frame member so that it partially overlaps in the vehicle longitudinal direction with the power control apparatus. Also, when there is a collision, the barrier penetrates the engine compartment while crushing the vehicle frame member and the support of the auxiliary battery. Consequently, the auxiliary battery moves past the power control apparatus such that the auxiliary battery does not interfere with the power control apparatus. As a result, the power control apparatus is able to be protected and can be rapidly discharged. It should be noted that the support illustrated in this example embodiment has the expanding and contracting portion, but the invention is not limited to this. That is, the support may also be configured to move along a guide groove on the side member.