Protection structure of high-voltage module

Abstract

A protection structure for a high-voltage module for converting electric power supplied between a motor, which is a driving force source, and a power source, in which the high-voltage module is housed in a case having side wall parts on both sides in the vehicle width direction and a front wall part on the front side in the traveling direction of the vehicle, the front wall portion has a central portion, which is a central portion in the vehicle width direction, and connecting portions at both ends in the vehicle width direction, the connecting portions being formed at positions rearward of the central portion, and the protection structure is provided with a bracket disposed forward of the central portion with a predetermined gap therebetween, both ends of the bracket being connected to the connecting portions.

Description

TECHNICAL FIELD

[0001] The present application relates to a structure for protecting a high voltage module that connects a power supply mounted on a vehicle and an electric motor that is a driving force source. BACKGROUND

[0002] In Japanese Patent Application Publication No. 2012-139012, a power conversion device is described that connects with an alternating-current electric motor that is a driving force source of a hybrid electric vehicle and a direct-current power supply. In this power conversion device, an inverter circuit that converts direct-current power output from the direct-current power supply to alternating-current power and outputs to the alternating-current electric motor, and converts alternating-current power generated by the alternating-current electric motor to direct-current power and outputs to the direct-current power supply is provided. In this power conversion device, a capacitor module or the like for smoothing direct-current power supplied to the inverter circuit is provided. SUMMARY

[0003] As with the alternating-current electric motor described in Japanese Patent Application Publication No. 2012-139012, an electric motor provided as a driving force source of a vehicle can increase output torque by increasing the power that is electrified. In other words, in a case where the running region in which the vehicle runs by the electric motor is increased in order to reduce the load on the engine or the output of the electric motor is increased in order to increase the maximum torque of the vehicle, the voltage applied to the power conversion device becomes high. Also, in a case where the maximum torque of a vehicle in which the electric motor is the only driving force source, such as an electrified vehicle, is increased, the voltage applied to the power conversion device becomes high. Therefore, in order to reduce the resistance of the power conversion device or improve durability, the power conversion device becomes large.

[0004] As the power conversion device becomes large like this, the power conversion device can protrude to the front side of the engine or the power transmission device or the like in the direction in which the vehicle travels. In this case, since the member that receives the collision load from the outside is not on the front side of the power conversion device, a large collision load can act on the power conversion device including the housing that houses the inverter or the capacitor or the like at the time of a vehicle collision. Also, as the power conversion device becomes large as described above, the space in which the energy absorbing member that receives the collision load from the outside is mounted is limited, and the mountability of the energy absorbing member can decrease.

[0005] The present application was achieved in light of the above-described technical problem, and aims to provide a protection structure for a high voltage module that can improve the protection performance of the high voltage module at the time of a vehicle collision.

[0006] To achieve the above object, the present application provides a protection structure of a high-voltage module for converting electric power supplied between an electric motor as a driving power source of a vehicle and a power supply of the electric motor, wherein the high-voltage module is housed in a case having a side wall portion on both sides in a vehicle width direction and a front wall portion on a front side in a traveling direction of the vehicle, the front wall portion has a central portion in the vehicle width direction and a connecting portion on both ends in the vehicle width direction, the connecting portion is formed at a position further rearward than the central portion in the traveling direction of the vehicle, and the protection structure is provided with a bracket disposed on the front side further than the central portion in the traveling direction of the vehicle with a prescribed gap and connected to the connecting portion on both ends in the vehicle width direction.

[0007] Also, in the present application, the connecting portion can be constituted by an inclined surface that gradually recedes from the central portion toward the outside in the vehicle width direction.

[0008] Also, in the present application, the high-voltage module can be provided in a front compartment of the vehicle.

[0009] Also, in the present application, the bracket can be formed at the same height as the case in a vehicle height direction.

[0010] Also, in the present application, a transfer drive axle case housing a power transmission device that transmits torque from the electric motor to a drive wheel is further provided, and the front wall portion can be provided so as to protrude further forward than a front end portion of the transfer drive axle case in the traveling direction of the vehicle.

[0011] According to the present application, a bracket is provided on the front side of a case housing a high-voltage module with a prescribed gap. Therefore, in the event of a collision of the vehicle with an obstacle or the like in front, the bracket receives the collision load. The collision load acting on the bracket is transmitted to the connecting portions on both ends of the case via both ends of the bracket. Therefore, the load input to the case can be received by the connecting portions, which are higher in rigidity with respect to the collision load. As a result, the load acting on the central portion of the front wall portion of the case can be reduced, and damage to the high-voltage module accompanying deformation of the front wall portion of the case or exposure of the high-voltage module due to damage to the case or the like can be suppressed. In other words, the protection performance of the case at the time of a collision of the vehicle can be improved.

[0012] Also, since the connecting portions are formed at positions further rearward than the central portion, the gap between the bracket and the front wall portion of the case can be suppressed from becoming too large while ensuring a space for mounting the bracket. In other words, even in the case where the gap between the case and a component or the like disposed on the front side of the case is small, the bracket for protecting the case can be mounted. BRIEF DESCRIPTION OF DRAWINGS

[0013] Features, advantages, and technical and industrial significance of exemplary embodiments of the present application will be described below with reference to the accompanying drawings, wherein like numerals designate like elements, and wherein:

[0014] Figure 1A is a diagram schematically showing an example of an electrified vehicle in which a high-voltage module in an embodiment of the present application is mounted, and is a plan view of a front compartment of the electrified vehicle.

[0015] Figure 1B is a diagram schematically showing an example of an electrified vehicle in which a high-voltage module in an embodiment of the present application is mounted, and is a side view of the front compartment.

[0016] Figure 2A is an enlarged view schematically showing a PCU case, and is a plan view of the PCU case.

[0017] Figure 2B is an enlarged view schematically showing a PCU case, and is a side view of the PCU case. DETAILED DESCRIPTION

[0018] The present application will be described in accordance with the embodiment shown in the drawings. In addition, the embodiment described below is merely an example in the case of embodying the present application, and does not limit the present application.

[0019] In Figure 1A and Figure 1B an example of an electrified vehicle in which a high-voltage module in an embodiment of the present application is mounted is schematically shown. In addition, Figure 1A a plan view of a front compartment 1 of an electrified vehicle (hereinafter, simply referred to as a vehicle) Ve is shown, Figure 1B a side view of the front compartment 1 is shown.

[0020] Figure 1A and Figure 1B The vehicle Ve shown in Figs. 1 to 4 is provided with an electric motor 2 as a driving force source. The electric motor 2 is constituted by an alternating-current electric motor such as a synchronous electric motor or an induction electric motor. This is the same as an electric motor provided as a driving force source in a conventional hybrid electric vehicle or a battery electric vehicle, etc. That is, in addition to a function as an electric motor that generates a driving torque by supplying alternating-current electric power, a function as a generator that converts power of an output shaft into electric power by being driven by the output shaft is also provided.

[0021] The electric motor 2 is equipped with a reduction mechanism for amplifying the torque of the electric motor 2 or a differential mechanism for dividing the torque of the electric motor and transmitting it to the left and right drive wheels, and the power transmission device 3 is connected to one end of the drive shaft. That is, the power transmission device 3 is arranged such that the rotation center axis L of the output component of the power transmission device 3 is the same axis as the rotation center axis of the drive shaft.

[0022] Figure 1A and Figure 1B In the vehicle Ve shown, the electric motor 2 and the power transmission device 3 are arranged side-by-side in the vehicle width direction, such that the rotation center axis of the electric motor 2 is the same as the rotation center axis L of the output component constituting the power transmission device 3. Specifically, the motor housing 2a that houses the electric motor 2 and the transmission drive axle housing 3a that houses the power transmission device 3 are arranged side-by-side in the vehicle width direction, and these housings 2a and 3a are connected by bolts or the like. Alternatively, the structure or arrangement of the electric motor 2 and the power transmission device 3 can be appropriately modified, for example, the rotation center axis of the electric motor 2 can be arranged parallel to the rotation center axis L of the output component constituting the power transmission device 3.

[0023] and, Figure 1A and Figure 1B The vehicle Ve shown includes a fuel cell 4 that functions as a power source for the electric motor 2 and an energy storage device 5. The fuel cell 4 can be configured similarly to those found in conventional fuel cell electric vehicles. That is, it consists of multiple fuel cell units that generate direct current (DC) electricity through a chemical reaction between hydrogen supplied from a hydrogen storage tank (not shown) and oxygen contained in air drawn in through an air filter (not shown). These fuel cell units are connected in series and housed in an FC housing 4a. The FC housing 4a is fixed to a rigid component (not shown) constituting the vehicle body by bolts or the like. Furthermore, the front end face of the FC housing 4a is configured to protrude beyond the front end face of the transmission drive axle housing 3a.

[0024] The energy storage device 5, like those found in conventional hybrid electric vehicles or pure electric vehicles, is composed of lithium-ion batteries or capacitors. That is, the energy storage device 5 is configured to output direct current (DC) power and charge the battery by supplying DC power. Furthermore, for convenience, in... Figure 1A and Figure 1B The energy storage device 5 is shown at the lower end of the front side of the cab, but the location of the energy storage device 5 is not particularly limited.

[0025] A power conversion unit 6, equivalent to a "high-voltage module" in the embodiments of the present invention, is provided on the upper part of the FC housing 4a. This power conversion unit 6 consists of an inverter 6a, a driver circuit 6b, etc. The inverter 6a converts the DC power output from the fuel cell 4 or the energy storage device 5 into AC power and outputs it to the motor 2, and converts the AC power generated by the motor 2 into DC power and outputs it to the energy storage device 5. The driver circuit 6b outputs drive pulses to a switching element (not shown) constituting the inverter 6a. These inverters 6a and driver circuits 6b are housed in a PCU housing 7, equivalent to a "housing" in the embodiments of the present invention. The PCU housing 7 is fixed to the upper part of the FC housing 4a by bolts or the like. Furthermore, the end face of the PCU housing 7 on the vehicle front side of the FC housing 4a is configured to be substantially the same. That is, the end face of the PCU housing 7 on the vehicle front side is configured to protrude more than the end face of the transmission drive axle housing 3a on the vehicle front side.

[0026] and, Figure 1A and Figure 1B The electric motor 2, power transmission device 3, fuel cell 4, power conversion unit 6, and intercooler (not shown) that cools the air supplied to the fuel cell 4 are configured to be cooled by circulating cooling water. A radiator 8 for dissipating the heat of the cooling water is located at the front of the front compartment 1. This radiator 8 is fixed to a front crossbeam (not shown) and a radiator core support (not shown), similar to radiators in conventional vehicles. The front crossbeam is configured to span the front ends of the left and right side longitudinal beams. The radiator core support is configured to span the front ends of the left and right front inner sides (not shown). That is, the radiator 8 is located further forward of the vehicle Ve than the FC housing 4a, PCU housing 7, etc.

[0027] When the vehicle Ve is driven under low loads, such as during start-up or when low driving force is required, it supplies power from the energy storage device 5 to the electric motor 2. When the vehicle Ve is driven steadily, it supplies power from the fuel cell 4 to the electric motor 2. When the vehicle Ve is driven under high loads, such as when high driving force is required, it supplies power from both the fuel cell 4 and the energy storage device 5 to the electric motor 2. Furthermore, during braking, the power generated by the electric motor 2 is used to charge the energy storage device 5, and the power generated by the fuel cell 4 when the vehicle is stopped is also used to charge the energy storage device 5.

[0028] As described above, the transmission and reception of electricity between the fuel cell 4 and the energy storage device 5 and the electric motor 2, as well as the supply of electricity from the fuel cell 4 to the energy storage device 5, are performed via the power conversion unit 6. Therefore, the power required to meet the driving power of the vehicle Ve flows through this power conversion unit 6. Consequently, a bracket 9 is integrally provided on the PCU housing 7, which spans along the vehicle width direction with a gap between it and the front end face of the vehicle Ve of the PCU housing 7.

[0029] existFigure 2A and Figure 2B An enlarged view of the PCU housing 7 is shown schematically. Additionally, Figure 2A This shows a top view of the PCU housing 7. Figure 2B This shows a side view of the PCU housing 7. (Example) Figure 2A and Figure 2B As shown, the PCU housing 7 is composed of side wall portions 10 on both sides in the vehicle width direction, a front wall portion 11 on the front side in the vehicle Ve's travel direction, and a rear wall portion 12 on the rear side in the vehicle Ve's travel direction.

[0030] The aforementioned front wall portion 11 has a central portion 11a in the vehicle width direction and connecting portions 11b at both ends in the vehicle width direction. The connecting portions 11b are formed as inclined surfaces that gradually recede from the central portion 11a towards the outer side in the vehicle width direction. That is, the connecting portions 11b are formed at a position further rearward than the central portion 11a in the vehicle Ve's travel direction. In the following description, the connecting portion 11b will be referred to as the inclined surface 11b.

[0031] A boss 13 protruding toward the front of the vehicle Ve is integrally formed on the inclined surface 11b. Specifically, the boss 13 is integrally formed with the PCU housing 7 by casting.

[0032] The front end face of the boss portion 13 is formed to be at the same position as or more prominent than the end face of the vehicle front side of the PCU housing 7, and a bracket 9 spanning along the vehicle width direction is fixed to its front end face. Specifically, the bracket 9 is fixed to the boss portion 13 by forming an internal thread on the boss portion 13 and screwing a bolt (not shown) into the internal thread.

[0033] The bracket 9 bears the load (collision load) during a vehicle Ve collision and is formed in a rectangular shape to cover the front surface of the PCU housing 7. That is, the length (height) of the bracket 9 in the vehicle height direction is the same as that of the PCU housing 7. Furthermore, the bracket 9 is made of a highly rigid material such as metal to obtain rigidity relative to a predetermined collision load, and its cross-sectional shape (section modulus) is determined.

[0034] Furthermore, the boss portion 13 or the bracket 9 can be integrated with the PCU housing 7. Therefore, the boss portion 13 and the PCU housing 7 can be formed separately and connected by welding or the like, or the PCU housing 7, the boss portion 13, and the bracket 9 can be integrally formed by casting or the like.

[0035] As described above, since a bracket 9 is provided on the front side of the PCU housing 7, the bracket 9 bears the collision load in the event of a collision between the vehicle Ve and an obstacle in front. The collision load acting on the bracket 9 is input to the PCU housing 7 via the boss portion 13. As described above, the boss portion 13 is connected to the inclined surfaces 11b formed on the left and right sides of the PCU housing 7. Therefore, the load input to the PCU housing 7 from the boss portion 13 can be borne by the side wall portion 10 of the PCU housing 7, which has a higher rigidity relative to the collision load. As a result, the load acting on the front surface of the PCU housing 7 can be reduced, and damage to electrical components such as the inverter 6a or driver circuit 6b caused by deformation of the front surface of the PCU housing 7, or exposure of electrical components caused by damage to the PCU housing 7, can be suppressed. In other words, the protective performance of the PCU housing 7 in the event of a collision with the vehicle Ve can be improved.

[0036] Furthermore, as described above, by providing the bracket 9 in a manner that covers the front surface of the PCU housing 7, even if the front surface of the PCU housing 7 cracks during a vehicle Ve collision, it is possible to prevent electrical components from being exposed to the outside.

[0037] Furthermore, by connecting the boss portion 13 to the inclined surface 11b, the length of the boss portion 13 used for mounting the bracket 9 can be ensured, while preventing the gap between the bracket 9 and the front surface of the PCU housing 7 from becoming too large. In other words, even when the gap between the PCU housing 7 and the heat sink 8 or the like disposed on the front side of the PCU housing 7 is small, the bracket 9 used to protect the PCU housing 7 can still be installed.

[0038] Furthermore, as described above, the boss portion 13 only needs to be able to be installed at a position that transfers the load to the side wall portion of the PCU housing 7 and is retracted from the front wall portion 11 of the PCU housing 7. For example... Figure 2A and Figure 2B As shown by the dashed line, stepped portions 14 that are recessed from the front surface of the PCU housing 7 can be formed on the left and right sides of the PCU housing 7, and the boss portion 13 can be fixed to the stepped portions 14.

[0039] Furthermore, as described above, the high-voltage module in the embodiments of the present invention is not limited to a high-voltage module installed in the front compartment, but can also be installed in the rear compartment, with a bracket installed in a manner that allows it to withstand collision loads when reversing. That is, the bracket can be connected to the rear side of the high-voltage module (the front side in the direction of travel when reversing).

[0040] Furthermore, the high-voltage module in the embodiments of the present invention is not limited to the power conversion unit installed in a fuel cell electric vehicle. It can also be the power conversion unit installed in a battery electric vehicle or a hybrid electric vehicle, etc.

Claims

1. A protection structure of a high-voltage module that converts electric power supplied between an electric motor that is a drive power source of a vehicle and a power supply of the electric motor, characterized by: the high-voltage module is housed in a case that has side wall portions on both sides in a vehicle width direction and a front wall portion on a front side in a traveling direction of the vehicle, the front wall portion has a central portion, that is, a center portion in the vehicle width direction, and joint portions on both ends in the vehicle width direction, the joint portions are formed at positions that are more rearward than the center portion in the traveling direction of the vehicle, the protection structure is provided with a bracket that is disposed on a more front side than the center portion in the traveling direction of the vehicle with a prescribed gap therebetween and is joined to the joint portions on both ends in the vehicle width direction.

2. The protection structure of the high-voltage module according to claim 1, characterized in that: the joint portions are constituted by inclined surfaces that gradually recede from the center portion toward the outside in the vehicle width direction.

3. The protection structure of the high-voltage module according to claim 1, characterized in that: the high-voltage module is disposed in a front compartment of the vehicle.

4. The protection structure of the high-voltage module according to claim 1, characterized in that: the bracket is formed at the same height as the case in a vehicle height direction.

5. The protection structure of the high-voltage module according to claim 1, characterized in that: the protection structure is further provided with a transfer case that houses a power transmission device that transmits torque from the electric motor to drive wheels, the front wall portion is disposed so as to protrude more forward than a front end portion of the transfer case in the traveling direction of the vehicle.

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