JP2016055667A - Electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for promptly stopping a motor when a collision occurs to an electric vehicle.SOLUTION: An electric vehicle comprises: a motor MG for wheel driving, having a plurality of stator coils 64; a conductor 76 fixed to an inner wall surface of a motor cover 72 via an insulator 74; and a side member 4 having transmission means 4a that transmits a buffer load to a fixing region 72a of the motor cover 72 to which the conductor 76 is fixed. The transmission means 4a of the side member 4 brings the conductor 76 into contact with at least two out of the plurality of stator coils 64U, 64V, and 64W by deforming the motor cover 72 by the buffer load transmitted during a collision, thereby forming a closed circuit that includes at least one of the stator coils 64U, 64V, and 64W.SELECTED DRAWING: Figure 3

Description

  The technology disclosed in the present specification relates to an electric vehicle including a wheel driving motor.

  A wheel driving motor provided in an electric vehicle is driven by using AC power supplied from an inverter. The inverter has a large-capacity smoothing capacitor in order to suppress a pulsation of a current accompanying a switching operation when converting DC power into AC power. For this reason, for the purpose of ensuring safety, development of a technique for quickly discharging the electric charge charged in the smoothing capacitor when the electric vehicle collides with an obstacle has been advanced.

  Patent Document 1 discloses a technique in which an inverter is operated so as to perform zero torque control of a motor at the time of a collision, and the electric charge charged in a smoothing capacitor is consumed by a stator coil of the motor.

JP 2013-110838 A

  For example, if the shaft is detached from the motor at the time of a collision, a situation in which the motor continues to rotate due to inertia occurs. In the technique of Patent Document 1, when the inverter is operated before the rotation of the motor is stopped, a counter electromotive current generated in the stator coil of the motor flows into the smoothing capacitor via the inverter. For this reason, in the technique of Patent Document 1, it is necessary to operate the inverter after the rotation of the motor is stopped. As a result, the time required to discharge the electric charge charged in the smoothing capacitor becomes long.

  This specification provides a technique for quickly stopping a motor in the event of a collision of an electric vehicle.

  One embodiment of an electric vehicle disclosed in the present specification includes a wheel driving motor, a conductor, and a side member. The motor is housed in a motor cover and has a plurality of stator coils. The conductor is fixed to the inner wall surface of the motor cover via an insulator. The side member has a transmission means for transmitting the collision load to a fixed region of the motor cover where the conductor is fixed. The transmission means of the side member causes the conductor to contact at least two of the plurality of stator coils by deforming the motor cover with a collision load to be transmitted at the time of collision, whereby at least one of the plurality of stator coils. Is configured to form a closed circuit including two.

  When the electric vehicle of the above-described embodiment collides, the conductor moves by the transmission member of the side member and contacts at least two of the plurality of stator coils. A closed circuit including the stator coil is formed by a short circuit through the conductor. A demagnetizing force is generated in the stator coil in the closed circuit by the counter electromotive force of the motor. The demagnetizing force acts in a direction to stop the rotation of the motor and can apply braking to the motor. Thus, the electric vehicle of the above embodiment can quickly stop the motor at the time of a collision.

It is a typical perspective view which shows an example of the device layout in the front compartment of an electric vehicle. It is a schematic plan view which shows an example of the device layout in the front compartment of an electric vehicle. It is a typical expanded sectional view of the motor periphery before a collision. It is a typical expanded sectional view of the motor periphery after a collision.

  Hereinafter, an embodiment of an electric vehicle (hybrid vehicle) including an engine and a motor will be described with reference to the drawings. In all the drawings, the arrow direction of the X axis corresponds to the front of the vehicle, the Y axis corresponds to the lateral direction of the vehicle, and the arrow direction of the Z axis corresponds to the upper side (vertically upward) of the vehicle.

  First, with reference to FIG.1 and FIG.2, the main device groups mounted in the front compartment 10 of the electric vehicle 100 are demonstrated. A main device group mounted in the front compartment 10 is an engine 1, a transaxle 2, a front member 3, a pair of side members 4, and a power controller 5. The engine 1 and the transaxle 2 are supported by the side member 4 via a mounting bracket (not shown).

  The transaxle 2 has a power distribution mechanism and a wheel driving motor therein. The motor also functions as a generator depending on the situation. The power distribution power distribution mechanism is configured to distribute / fuse the outputs of the engine and the motor and transmit them to the axle. Further, the power distribution mechanism may efficiently distribute the power from the engine to the traveling and the motor. In this case, the motor functions as a generator and generates power with the power from the engine. Electric vehicle 100 controls the power distribution mechanism to switch between a mode that travels only by the engine, a mode that travels by only the motor, and a mode that travels by the combined output of the engine and the motor based on the travel situation. Can do.

  The power controller 5 is for controlling the motor in the transaxle 2 and is fixed to the upper surface of the transaxle 2. The power controller 5 is configured to transform the direct current voltage supplied from the battery into an alternating current voltage, and supply it to the motor in the transaxle 2. Specifically, the power controller 5 includes a converter and an inverter. The converter boosts a DC voltage of about 300 V, which is an output voltage of the battery, to about 600 V suitable for driving the motor, and supplies it to the inverter. The inverter converts the boosted voltage of about 600 V into an AC voltage and supplies it to the motor in the transaxle 2. A smoothing capacitor for smoothing the input current to the inverter is connected between the converter and the inverter. The power controller 5 handles a large current in order to drive a motor for driving the vehicle. For this reason, a large capacity capacitor is used as the smoothing capacitor. Therefore, at the time of a vehicle collision, it is necessary to quickly discharge the electric charge charged in the smoothing capacitor for the purpose of ensuring safety.

  As shown in FIG. 3, the wheel driving motor MG provided in the transaxle 2 is a three-phase AC motor, and includes a rotor 42 and a stator 44. The motor MG is accommodated in the motor cover 72. The motor cover 72 constitutes a part of the casing of the transaxle 2 (see FIGS. 1 and 2).

  The rotor 42 has a rotor core 52 and a rotor shaft 54. The rotor core 52 has a cylindrical shape, and a plurality of permanent magnets (not shown) are embedded in the circumferential direction at equal intervals in the vicinity of the outer peripheral portion thereof. The rotor shaft 54 penetrates and is fixed to the center of the rotor core 52. Both ends of the rotor shaft 54 are rotatably supported by bearing members such as bearings.

  The stator 44 has a stator core 62 and a stator coil portion 64. The stator core 62 has a ring shape that goes around the rotor core 52, and is formed by stacking a plurality of punched electromagnetic steel sheets, for example. Stator coil portion 64 includes U-phase stator coil 64U, V-phase stator coil 64V, and W-phase stator coil 64W. Each of U-phase stator coil 64 </ b> U, V-phase stator coil 64 </ b> V, and W-phase stator coil 64 </ b> W is configured to be wound around the teeth of stator core 62. The U-phase stator coil 64U is disposed on the inner peripheral side of the stator core 62, the W-phase stator coil 64W is disposed on the outer peripheral side of the stator core 62, and the V-phase stator coil 64V includes the U-phase stator coil 64U and the W-phase stator. It arrange | positions between the coils 64W. Each of U-phase stator coil 64 </ b> U, V-phase stator coil 64 </ b> V, and W-phase stator coil 64 </ b> W is composed of eight stator coils arranged at equal intervals along the circumferential direction of stator core 62.

  A conductor 76 and an insulator 74 are fixed to a part of the inner wall surface of the motor cover 72. The conductor 76 is fixed to the inner wall surface of the motor cover 72 via an insulator 74. The conductor 76 is a material having conductivity. For example, the conductor 76 is a metal plate. The insulator 74 is a material having an insulating property. For example, the insulator 74 is an insulating double-sided tape, and adheres the motor cover 72 and the conductor 76. Here, a region of the motor cover 72 where the conductor 76 is fixed is referred to as a fixed region 72a.

  The conductor 76 is disposed to face the stator coil portion 64. No other member is interposed in the space between the conductor 76 and the stator coil portion 64. The conductor 76 has a form extending in the direction in which the U-phase stator coil 64U, the V-phase stator coil 64V, and the W-phase stator coil 64W overlap. As will be described later, the U-phase stator coil 64U and the V-phase stator coil. It has a length sufficient to simultaneously contact the 64V and W-phase stator coils 64W.

  The side member 4 has a transmission means 4a. The transmission means 4 a is configured by a bead formed on a part of the side member 4. The transmission means 4a of the side member 4 is a part where a part of the side member 4 becomes weaker than the surroundings due to this bead. The bead is configured to be a starting point at which the side member 4 is bent and deformed when subjected to a collision load. The transmission means 4 a of the side member 4 is disposed at a position facing the fixed area 72 a of the motor cover 72. In addition, the transmission means 4a using a bead is an example, and as the transmission means 4a of the side member 4, various techniques that are more fragile than the surroundings and can be bent and deformed by a collision load can be employed.

  Next, the case where the electric vehicle 100 collides with a small overlap will be described. In the small overlap collision, the electric vehicle 100 receives a collision load from the F direction in FIG. As shown in FIG. 4, when the electric vehicle 100 collides with a small overlap, the transmission means 4 a of the side member 4 is bent inward with priority over the surroundings, and the collision load is transmitted to the fixing region 72 a of the motor cover 72. Then, the motor cover 72 is deformed inward. As a result, the conductor 76 fixed to the fixing region 72a of the motor cover 72 moves inward and contacts the U-phase stator coil 64U, the V-phase stator coil 64V, and the W-phase stator coil 64W. As a result, the U-phase stator coil 64U, the V-phase stator coil 64V, and the W-phase stator coil 64W are short-circuited, so that several stator coils constituting the U-phase stator coil 64U and several stators constituting the V-phase stator coil 64V A closed circuit including a number of stator coils constituting the coil and the W-phase stator coil 64W is formed. A counter magnetic force is generated in the stator coil in the closed circuit by the counter electromotive force of the motor MG. The demagnetizing force acts in a direction to stop the rotation of the motor MG, applies braking to the motor MG, and quickly stops the rotation of the motor MG. For this reason, in electric powered vehicle 100, even when rotor shaft 54 comes out of rotor core 52 at the time of a collision, rotation of motor MG stops quickly.

  After the rotation of the motor MG stops, the power controller 5 operates the inverter so that the motor MG is controlled to zero torque, and the electric charge charged in the smoothing capacitor is consumed by the stator coil 64 of the motor MG. Thus, in electric vehicle 100, since rotation of motor MG stops quickly, the electric charge charged in the smoothing capacitor can also be discharged quickly.

  For example, instead of the above example, in order to form a closed circuit at the time of a collision, an embodiment in which circuit elements for short-circuiting a motor at the time of a collision are connected, and an embodiment in which all transistors constituting the inverter are turned on at the time of a collision are also considered. It is done. However, in these embodiments, if the electric wiring (power wiring, input / output wiring, etc.) connected to the circuit element and the inverter is damaged at the time of the collision, the closed circuit cannot be formed at the time of the collision, and the motor MG is quickly stopped. I can't let you. On the other hand, in the electric vehicle 100, the stator coil portion 64 is short-circuited by utilizing the deformation of the motor cover 72 at the time of the collision, thereby forming a closed circuit including the stator coil. For this reason, the electric vehicle 100 can stop the motor MG quickly using the collision load regardless of the damage of the electric wiring.

  In electrically powered vehicle 100, conductor 76 contacts all of U-phase stator coil 64U, V-phase stator coil 64V, and W-phase stator coil 64W at the time of a collision. For this reason, each of the U-phase stator coil 64U, the V-phase stator coil 64V, and the W-phase stator coil 64W generates a demagnetizing force due to the counter electromotive force. Therefore, a large amount of braking is applied to the motor MG, so that the motor MG is stopped. The time is short. As described above, each of U-phase stator coil 64U, V-phase stator coil 64V, and W-phase stator coil 64W includes eight coils. In order to generate counter electromotive force in many coils, the conductor 76 is preferably fixed to the inner wall surface of the motor cover 72 in the vicinity of the terminal block of the power cable through which the three-phase alternating current is transmitted from the power controller 5.

  The motor cover 72 of the embodiment constitutes a part of the casing of the transaxle 2. The motor cover may be a part of the case that houses the motor, and is not limited to a part of the casing of the transaxle 2. The “electric vehicle” in the present specification includes an electric vehicle including a wheel driving motor but not including an engine, and a hybrid vehicle including a wheel driving motor and an engine. A fuel cell vehicle including a wheel driving motor is also included in the “electric vehicle” in this specification.

  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.

4: Side member 4a: Transmission means 42: Rotor 44: Stator 52: Rotor core 54: Rotor shaft 62: Stator core 64: Stator coil portion 64U: U-phase stator coil 64V: V-phase stator coil 64W: W-phase stator coil 72: Motor Cover 72a: Fixed region 74: Insulator 76: Conductor 100: Electric vehicle MG: Motor

Claims (1)

A motor for driving a wheel housed in a motor cover and having a plurality of stator coils;
A conductor fixed to the inner wall surface of the motor cover via an insulator;
A side member having a transmission means for transmitting a collision load to a fixed region of the motor cover to which the conductor is fixed;
The transmission means of the side member brings the conductor into contact with at least two of the plurality of stator coils by deforming the motor cover with a collision load to be transmitted at the time of a collision, whereby the plurality of stators An electric vehicle configured to form a closed circuit including at least one of the coils.

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