High-voltage module protection structure

Abstract

This invention provides a protective structure for a high-voltage module that can improve the protective performance of the high-voltage module during a vehicle collision. [Solution] A protective structure for a high-voltage module that converts the power supplied between a motor as a driving force source and a power supply, wherein the high-voltage module is housed in a case having side walls on both sides in the vehicle width direction and a front wall on the front side in the direction of travel of the vehicle, the front wall having a central part which is the central part in the vehicle width direction and connecting parts at both ends in the vehicle width direction, the connecting parts being formed set back from the central part and arranged with a predetermined gap in front of the central part and having brackets at both ends connected to the connecting parts.

Description

Technical Field

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[0001] This invention relates to a structure for protecting a high-voltage module that connects a power source mounted on a vehicle and a motor as a driving force source.

Background Art

[0002] Patent Document 1 describes a power conversion device connected to an AC motor as a driving force source of a hybrid vehicle and a DC power source. This power conversion device includes an inverter circuit that converts DC power output from the DC power source into AC power and outputs it to the AC motor, and also converts AC power generated by the AC motor into DC power and outputs it to the DC power source, and a capacitor module for smoothing the DC power supplied to the inverter circuit. <##

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Like the AC motor described in Patent Document 1, a motor provided as a driving force source of a vehicle can increase its output torque by increasing the power supplied. In other words, when increasing the driving range using the motor to reduce the engine load, or when increasing the output of the motor to increase the maximum torque of the vehicle, or when increasing the maximum torque of a vehicle that uses only the motor as a driving force source such as an electric vehicle, the voltage applied to the power conversion device becomes high. Therefore, in order to reduce the electrical resistance of the power conversion device or improve its durability, the power conversion device becomes larger.

[0005] As power converters become larger, they may protrude forward from the engine and power transmission system in the direction of vehicle travel. In such cases, since there are no components that receive external collision loads in front of the power converter, a large collision load may act on the power converter, including the case housing the inverter and capacitors, during a vehicle collision. Furthermore, as power converters become larger as described above, the space available for mounting energy absorption components that receive external collision loads may be limited, potentially reducing the feasibility of mounting energy absorption components.

[0006] This invention was made in view of the above-mentioned technical problems, and aims to provide a protective structure for a high-voltage module that can improve the protective performance of the high-voltage module during a vehicle collision. [Means for solving the problem]

[0007] To achieve the above objective, this invention provides a protective structure for a high-voltage module that converts the power supplied between a motor as a driving force source for a vehicle and a power supply for the motor, wherein the high-voltage module is housed in a case having side walls on both sides in the vehicle width direction and a front wall on the front side in the direction of travel of the vehicle, the front wall having a central portion which is the central part in the vehicle width direction and connecting portions at both ends in the vehicle width direction, the connecting portions being formed set back from the central portion in the direction of travel of the vehicle, positioned forward of the central portion in the direction of travel of the vehicle with a predetermined gap, and comprising brackets at both ends in the vehicle width direction connected to the connecting portions.

[0008] Furthermore, in this invention, the connecting portion may be composed of an inclined surface that gradually recedes from the central portion toward the outside in the vehicle width direction.

[0009] Furthermore, in this invention, the high-voltage module may be provided in the front compartment of the vehicle.

[0010] Furthermore, in this invention, the bracket may be formed at the same height as the case in the vehicle height direction.

[0011] Furthermore, this invention further comprises a transaxle case housing a power transmission device that transmits torque from the motor to the drive wheels, and the front wall portion may be provided so as to protrude forward of the front end of the transaxle case in the direction of travel of the vehicle. [Effects of the Invention]

[0012] According to this invention, a bracket is provided on the front side of the case housing the high-voltage module, with a predetermined gap between them. Therefore, when a vehicle collides with an obstacle in front of it, the bracket bears the impact load. The impact load acting on the bracket is transmitted through both ends of the bracket to the connecting parts at both ends of the case. Consequently, the load applied to the case can be received at the connecting parts, which have relatively high rigidity against impact loads. As a result, the load acting on the central part of the front wall of the case can be reduced, thereby suppressing damage to the high-voltage module due to deformation of the front wall of the case, and preventing exposure of the high-voltage module due to damage to the case. In other words, the protective performance of the case during a vehicle collision can be improved.

[0013] Furthermore, since the connecting portion is formed set back from the central portion, it is possible to secure space for attaching the bracket while preventing the gap between the bracket and the front wall of the case from becoming excessively large. In other words, even if the gap between the case and components located on the front side of the case is small, a bracket for protecting the case can be attached. [Brief explanation of the drawing]

[0014] [Figure 1]This figure schematically shows an example of an electric vehicle equipped with a high-voltage module according to an embodiment of the present invention, where (a) is a top view of the front compartment of the electric vehicle and (b) is a side view of the front compartment. [Figure 2] This is a schematic enlarged view of the PCU case, where (a) is a top view of the PCU case and (b) is a side view of the PCU case. [Modes for carrying out the invention]

[0015] This invention will be described based on the embodiments shown in the figures. The embodiments described below are merely examples of how this invention can be implemented and do not limit it.

[0016] Figure 1 schematically shows an example of an electric vehicle equipped with a high-voltage module according to an embodiment of this invention. Figure 1(a) shows a top view of the front compartment 1 of the electric vehicle (hereinafter simply referred to as the vehicle) Ve, and Figure 1(b) shows a side view of the front compartment 1.

[0017] The vehicle Ve shown in Figure 1 is equipped with motor 2 as its driving force source. This motor 2 is composed of an AC motor such as a synchronous motor or induction motor, similar to motors used as driving force sources in conventional hybrid vehicles and electric vehicles. In other words, in addition to its function as a motor that generates driving torque when AC power is supplied, it also functions as a generator that converts that power into electricity when the output shaft is rotated along with it.

[0018] The motor 2 is equipped with a power transmission device 3, which includes a reduction mechanism to amplify the torque of the motor 2 and a differential mechanism to divide the motor's torque and transmit it to the left and right drive wheels. One end of the drive shaft is connected to this power transmission device 3. In other words, the power transmission device 3 is positioned so that the rotational axis L of the output member of the power transmission device 3 and the rotational axis of the drive shaft are on the same axis.

[0019] In the vehicle Ve shown in FIG. 1, the 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 motor 2 and the rotation center axis L of the output member constituting the power transmission device 3 are the same. Specifically, a motor case 2a that houses the motor 2 and a transaxle case 3a that houses the power transmission device 3 are arranged side by side in the vehicle width direction, and these cases 2a and 3a are connected by bolts or the like. Note that the configuration and arrangement of the motor 2 and the power transmission device 3 may be appropriately changed, such as the rotation center axis of the motor 2 and the rotation center axis L of the output member constituting the power transmission device 3 being arranged in parallel.

[0020] Also, the vehicle Ve shown in FIG. 1 includes a fuel cell 4 that functions as a power source for the motor 2 and a power storage device 5. The fuel cell 4 can be configured in the same manner as the fuel cell provided in a conventional fuel cell vehicle. That is, it is composed of a plurality of fuel cell units configured to generate DC power by a chemical reaction between hydrogen supplied from a hydrogen tank (not shown) and oxygen contained in the outside air taken in through an air cleaner (not shown) or the like. Those fuel cell units are connected in series and housed in an FC case 4a. This FC case 4a is fixed to a rigid member (not shown) constituting the vehicle body by bolts or the like. Note that the end face on the vehicle front side in the FC case 4a is arranged to protrude beyond the end face on the vehicle front side of the transaxle case 3a.

[0021] The power storage device 5 is composed of a lithium ion battery, a capacitor, or the like in the same manner as the power storage device provided in a conventional hybrid vehicle, electric vehicle, or the like. That is, the power storage device 5 is configured to output DC power and to be charged with power when DC power is supplied. Note that in FIG. 1, the power storage device 5 is shown at the lower end portion on the front side of the cabin for the sake of convenience, but the position where the power storage device 5 is mounted is not particularly limited.

[0022] On the upper part of the above-described FC case 4a, a power conversion unit 6 corresponding to the "high-voltage module" in the embodiment of the present invention is provided. This power conversion unit 6 converts the DC power output from the fuel cell 4 and the power storage device 5 into AC power and outputs it to the motor 2, and also converts the AC power generated by the motor 2 into DC power and outputs it to the power storage device 5. It is composed of an inverter 6a and a driver circuit 6b that outputs drive pulses to switch elements (not shown) constituting the inverter 6a. The inverter 6a and the driver circuit 6b are housed in a PCU case 7 corresponding to the "case" in the embodiment of the present invention. This PCU case 7 is fixed to the upper part of the FC case 4a by bolts or the like. Note that the end faces on the front side of the vehicle Ve of the PCU case 7 and the FC case 4a are arranged to be substantially the same. That is, the end face on the front side of the vehicle of the PCU case 7 is arranged to protrude more than the end face on the front side of the vehicle of the transaxle case 3a.

[0023] Also, the motor 2, the power transmission device 3, the fuel cell 4, the power conversion unit 6 shown in FIG. 1, and an intercooler (not shown) that cools the air supplied to the fuel cell 4 are configured to be cooled by flowing cooling water, and a radiator 8 for radiating the heat of the cooling water is provided on the front side of the front compartment 1. This radiator 8 is fixed to a front cross member (not shown) spanning the front ends of the left and right side members and a radiator core support (not shown) spanning the front ends of the left and right front insides, similar to the radiator provided in a conventional vehicle. That is, the radiator 8 is arranged in front of the vehicle Ve more than the FC case 4a, the PCU case 7, etc.

[0024] As described above, the vehicle Ve supplies power to the motor 2 from the energy storage device 5 during low-load driving, such as when starting or when the required driving force is low; power to the motor 2 from the fuel cell 4 during steady-state driving; and power to the motor 2 from both the fuel cell 4 and the energy storage device 5 during high-load driving, such as when the required driving force is high. Furthermore, during braking, the power generated by the motor 2 charges the energy storage device 5, and when stopped, the power generated by the fuel cell 4 also charges the energy storage device 5.

[0025] The exchange of power between the fuel cell 4 and the energy storage device 5 and the motor 2, as well as the supply of power from the fuel cell 4 to the energy storage device 5, are carried out via the power conversion unit 6. Therefore, power sufficient to satisfy the driving power required for the vehicle Ve flows through the power conversion unit 6. For this reason, the PCU case 7 is integrally provided with a bracket 9 that spans across the vehicle width direction with a gap between it and the front end face of the PCU case 7 on the vehicle Ve side.

[0026] Figure 2 schematically shows an enlarged view of the PCU case 7. Figure 2(a) shows a top view of the PCU case 7, and Figure 2(b) shows a side view of the PCU case 7. As shown in Figure 2, the PCU case 7 is composed of side walls 10 on both sides in the vehicle width direction, a front wall 11 on the front side in the direction of travel of the vehicle Ve, and a rear wall 12 on the rear side in the direction of travel of the vehicle Ve.

[0027] The front wall portion 11 described above has a central portion 11a in the vehicle width direction and connecting portions 11b at both ends in the vehicle width direction, and the connecting portions 11b are formed as inclined surfaces that gradually recede from the central portion 11a toward the outside in the vehicle width direction. That is, the connecting portions 11b are formed to be set back from the central portion 11a in the direction of travel of the vehicle Ve. In the following description, the connecting portions 11b will be referred to as inclined surfaces 11b.

[0028] A boss portion 13 protruding toward the front of the vehicle Ve is integrally formed on this inclined surface 11b. Specifically, the boss portion 13 is integrally molded together with the PCU case 7 by casting.

[0029] The tip surface of this boss portion 13 is formed at the same position as, or protruding from, the end surface on the front side of the PCU case 7 on the vehicle Ve side, and a bracket 9, which spans in the vehicle width direction, is fixed to this tip surface. Specifically, the bracket 9 is fixed to the boss portion 13 by forming an internal thread in the boss portion 13 and screwing a bolt (not shown) into the internal thread.

[0030] Bracket 9 is designed to withstand the load (collision load) during a collision of the vehicle Ve, and is formed in a rectangular shape to cover the front of the PCU case 7. In other words, the length (height) of bracket 9 in the vehicle height direction is the same as that of the PCU case 7. Furthermore, bracket 9 is made of a relatively rigid material such as metal, and its cross-sectional shape (section modulus) is predetermined to achieve rigidity against a predetermined collision load.

[0031] Furthermore, the boss portion 13 and the bracket 9 only need to be integrated with the PCU case 7. Therefore, the boss portion 13 and the PCU case 7 may be molded separately and connected by welding or the like, or the PCU case 7, boss portion 13, and bracket 9 may be integrally molded by casting or the like.

[0032] As described above, since a bracket 9 is provided on the front side of the PCU case 7, when the vehicle Ve collides with an obstacle in front of it, the bracket 9 receives the collision load. The collision load acting on the bracket 9 is input to the PCU case 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 case 7. Therefore, the load input to the PCU case 7 from the boss portion 13 can be received by the side walls 10 of the PCU case 7, which have relatively high rigidity against collision loads. As a result, the load acting on the front of the PCU case 7 can be reduced, and damage to electrical components such as the inverter 6a and driver circuit 6b due to deformation of the front of the PCU case 7, and exposure of electrical components due to damage to the PCU case 7, can be suppressed. In other words, the protective performance of the PCU case 7 during a collision of the vehicle Ve can be improved.

[0033] Furthermore, as described above, by providing the bracket 9 so as to cover the front of the PCU case 7, even if a crack occurs on the front of the PCU case 7 during a collision with the vehicle Ve, the bracket 9 covers the front of the PCU case 7, thus preventing electrical components from being exposed to the outside.

[0034] Furthermore, by connecting the boss portion 13 to the inclined surface 11b, it is possible to ensure the length of the boss portion 13 for attaching the bracket 9 while suppressing the gap between the bracket 9 and the front of the PCU case 7 from becoming excessively large. In other words, even if the gap between the PCU case 7 and the radiator 8 located in front of the PCU case 7 is small, the bracket 9 for protecting the PCU case 7 can be attached.

[0035] As mentioned above, the boss portion 13 only needs to be attached to the side wall of the PCU case 7 at a position that transmits the load and is set back from the front wall portion 11 of the PCU case 7. Alternatively, as shown by the dashed lines in Figure 2, stepped portions 14 that are recessed from the front surface of the PCU case 7 may be formed on the left and right sides of the PCU case 7, and the boss portion 13 may be fixed to these stepped portions 14.

[0036] Furthermore, the high-voltage module in this embodiment of the invention is not limited to being provided in the front compartment as described above, but may also be provided in the rear compartment and equipped with a bracket to receive the collision load during reverse driving. In other words, the bracket can be connected to the rear side of the high-voltage module (the front side in the direction of travel during reverse driving).

[0037] Furthermore, the high-voltage module in this embodiment of the invention is not limited to a power conversion unit installed in a fuel cell vehicle, but may also be a power conversion unit installed in an electric vehicle or a hybrid vehicle. [Explanation of symbols]

[0038] 1. Front compartment 2 motors 3. Power transmission device 4 fuel cell 4a FC case 5. Energy storage device 6 Power Conversion Unit 6A Inverter 6b Driver circuit 7 PCU Cases 8 Radiator 9 brackets 10 Side wall section 11 Front wall 11a Central part 11b Connecting part (slope) 13 Boss Section 14 Stepped section L is the axis of rotation. Vehicle

Claims

1. A protection structure for a high-voltage module that converts the power supplied between a motor as a driving force source for a vehicle and the power supply for the motor, The high-voltage module is housed in a case having side walls on both sides in the vehicle width direction and a front wall on the front side in the direction of travel of the vehicle. The front wall portion has a central portion which is the central part in the vehicle width direction and connecting portions at both ends in the vehicle width direction. The connecting portion is formed set back from the central portion in the direction of travel of the vehicle, The vehicle is provided with a bracket that is positioned forward of the central portion in the direction of travel of the vehicle, with a predetermined gap between the bracket and the central portion, and both ends in the vehicle width direction are connected to the connecting portion. A protective structure for a high-voltage module characterized by the following features.

2. A protective structure for a high-voltage module according to claim 1, The connecting portion is composed of an inclined surface that gradually recedes from the central portion toward the outside in the vehicle width direction. A protective structure for a high-voltage module characterized by the following features.

3. A protective structure for a high-voltage module according to claim 1, The high-voltage module is located in the front compartment of the vehicle. A protective structure for a high-voltage module characterized by the following features.

4. A protective structure for a high-voltage module according to claim 1, The bracket is formed to be at the same height as the case in the vehicle height direction. A protective structure for a high-voltage module characterized by the following features.

5. A protective structure for a high-voltage module according to claim 1, The transaxle case further comprises a power transmission device that transmits torque from the motor to the drive wheels, The front wall portion is provided so as to protrude forward of the front end of the transaxle case in the direction of travel of the vehicle. A protective structure for a high-voltage module characterized by the following features.

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