Electric vehicle with motor drive section

An electric vehicle includes a motor drive section that supplies electric power from a main battery to a motor to drive the motor. The motor drive section can include an inverter configured to convert direct current from the main battery into alternating current, and a capacitor configured to stabilize an operation of the inverter. A resistor is configured to discharge electric charge of the capacitor, and discharge operation unit can be configured to manually control the resistor to discharge the electric charge of the capacitor.

BACKGROUND

The present invention relates to an electric vehicle that provides an easy accessibility to electronic components.

2. Description of the Related Art

Patent Literature 1 (JP-A-No. 2008-228507) discloses a layout of control means, which executes vehicular control, and a wiring connection on a battery side in a housing space, which houses a battery. The control means and the wiring connection are disposed at a position where they are accessible only in a state in which the battery is dismounted from the housing space, and they are not accessible in a state in which the battery is mounted.

It is necessary to pay attention to the discharge of electric charge accumulated in a capacitor even when the battery is dismounted during maintenance, insofar as the capacitor of an electronic component is electrically charged.

SUMMARY

The present invention has been achieved in view of the above-mentioned problems and has an object to provide an electric vehicle that provides good discharge of the residual electric charges of a capacitor, thereby ensuring an easy accessibility to the electronic components.

According to a first embodiment, an electric vehicle can include a motor drive section that supplies electric power from a battery to a traveling motor to drive the traveling motor. The motor drive section can include an inverter configured to convert direct current from the battery into alternating current. A capacitor can be configured to stabilize an operation of the inverter. A discharge unit can be configured to discharge electric charge of the capacitor. A discharge operation unit can be configured to manually make the discharge means to discharge the electric charge of the capacitor.

According to another embodiment, the discharge operation unit is disposed such that the motor drive section is accessible by manually operating the discharge operation unit when accessing the motor drive section.

According to another embodiment, the discharge operation unit is a manual switch configured to connect a discharge circuit including the discharge unit to the capacitor.

According to another embodiment, the motor drive section is interposed between the battery and the traveling motor, and has a main contactor connecting the battery to the inverter of the motor drive section. A first switch can permit the main contactor to turn on. A second switch connects the discharge circuit to the capacitor. The discharge operation unit is configured to interlock the first switch with the second switch in order to turn on one of the first switch and the second switch and turn off the other.

According to another embodiment, a seat for a rider is provided, and the motor drive section is disposed below the seat.

In some embodiments, the discharge unit, which discharges the electric charge of the capacitor for stabilizing an operation of the inverter, and the discharge operation unit, which manually makes the discharge means to discharge the electric charge of the capacitor, are provided. This ensures good discharge of the residual electric charge of the capacitor of the motor drive section, thereby ensuring easy accessibility to the motor drive section as an electronic component when accessing the motor drive section during maintenance.

In some embodiments, the discharge operation unit is disposed such that the motor drive section is not accessible unless the discharge operation unit is manually operated when accessing the motor drive section. Accordingly, it is necessarily discharged when accessing the motor drive section.

In some embodiments, the discharge operation unit is a manual switch to connect the discharge circuit, which includes the discharge operation unit, to the capacitor, thus ensuring the discharge of the electric charge of the capacitor.

In some embodiments, the motor drive section is interposed between the battery and the traveling motor. The motor drive section has the main contactor connecting the battery to the inverter of the motor drive section, the first switch permitting the main contactor to turn on, and the second switch connecting the discharge circuit to the capacitor. The discharge operation unit turns on one of the first switch and the second switch and turns off the other. Thus, when discharging the electric charge of the capacitor, the main contactor is turned off. This prevents the motor drive section from driving the traveling motor when accessing the motor drive section.

In some embodiments, since the motor drive section is disposed below the seat, it is possible to shorten the wiring such as power lines supplied from the motor drive section to the traveling motor.

DETAILED DESCRIPTION

Preferred embodiments of the electric vehicle according to the present invention will be described below by referring to the accompanying drawings.

FIG. 1is a left side view of an electric vehicle10as a hybrid motorcycle according to an embodiment. Mechanisms and components, which are each symmetrically provided in a vehicle body, are designated such that a reference sign with “L” appended designates one arranged in left-side, while a reference sign with “R” appended designates one arranged in right-side.

A vehicle body frame12has a main frame14and rear frames16L and16R, which are separated into left and right and extend rearward from the main frame14. At the front end portion of the main frame14, a head tube20, which rotatably journals a steering stem18, is provided. At the lower end portion of the steering stem18, a pair of front forks22L and22R, which rotatably journal the front wheel WF, is provided. The front wheel WF is steerable with a handlebar24mounted above the steering stem18.

At the lower side of the main frame14, an engine26is suspended, and a motor such as a traveling motor28is mounted behind the engine such that a crankshaft of the engine and a rotary shaft28aof the motor28are coaxially arranged. The crankshaft (rotary shaft28aof the motor28) of the engine26transmits rotation force to a drive sprocket30via power-transmitting device or means, not shown.

A front end portion of a swing arm34, which supports a rear wheel WR, is swingably journaled to a pivot shaft32at the lower side of the main frame14. The rear upper portion of the swing arm34is suspended on the rear frame16with a rear cushion36. The drive sprocket30transmits rotation force to the rear wheel WR via, for example, a chain38.

A transmission is mounted at the rear position of the rotary shaft28aof the motor28. The transmission has a main shaft40and a counter shaft42, which interlock with the rotary shaft28a. A vehicle speed sensor (vehicle speed detecting means)44is disposed at a proximity of the counter shaft42. The vehicle speed sensor detects vehicle speed, which is speed of the electric vehicle10. A rotation speed sensor46is disposed at the rotary shaft28a. The rotation speed sensor46detects rotation speed of the crankshaft (rotary shaft28aof the motor28) of the engine26.

A front cover48is disposed at the upper portion of the front forks22L and22R. The front cover is a part of a vehicle body cover, which covers the electric vehicle10. A handlebar cover50is disposed above the front cover48. At the back side of the head tube20, a center cover52, which continues into the front cover48, is disposed as the vehicle body cover. At the rear of the center cover52, a body cover54as the vehicle body cover is disposed. Above the body cover54, a seat56for a rider to be seated is supported, while at the rear of the body cover54, a tail lamp58is disposed.

Above the rear frames16L and16R and below the seat56, a main battery60and a sub battery62are disposed. The main battery supplies the motor28with, for example, a voltage of 72V. The sub battery supplies the electronic components at the front side of the head tube20with, for example, a voltage of 12V. The electric power from the main battery60is supplied to the motor28via the motor drive section64, which is disposed above the main frame14and below the seat56.

Since the motor drive section64is disposed above the main frame14and below the seat56, it is possible to shorten the wiring such as power lines supplied from the motor drive section64to the traveling motor. Since the main battery60is disposed above the rear frames16L and16R and below the seat56(disposed at a proximity of the motor drive section64), it is possible to shorten the wiring such as power lines, which connects the motor drive section64and the main battery60.

An ECU66is disposed at the rear upper portion of the rear frames16L and16R, and controls the engine26and the motor drive section64in response to operation of a throttle grip (not shown) at the handlebar24. Thus, the engine26and the motor28output rotation force (drive power) according to the operation of the throttle grip.

FIG. 2andFIG. 3are circuit diagrams of the motor drive section64shown inFIG. 1. The motor drive section64has a precharge relay70, a resistor72, a fuse74, a main contactor76, an inverter78, a capacitor80, a first switch82, a second switch84, and a resistor86functioning as a discharge means.FIG. 2is a circuit diagram of the motor drive section64in a state where the first switch82is turned on, while the second switch84is turned off.FIG. 3is a circuit diagram of the motor drive section64in a state where the first switch82is turned off, while the second switch84is turned on.

The switch SW1of the precharge relay70and the resistor72, and the fuse74and the switch SW2of the main contactor76, are connected in parallel between the inverter78and the positive electrode of the main battery60. The precharge relay70has a coil C1, which is connected to the positive electrode of the sub battery via the ignition switch (main switch) IGNSW, while the main contactor76has a coil C2, which is connected to the positive electrode of the sub battery62via the first switch82and the ignition switch IGNSW.

As shown inFIG. 3, when the first switch82is turned off, even if the ignition switch IGNSW is turned on, current is not supplied to the coil C2of the main contactor76. Thus, the switch SW2of the main contactor76is not turned on. Accordingly, the first switch82is a switch to permit the main contactor76(switch SW2of the main contactor76) to turn on. When the first switch82is turned on, the main contactor76is permitted to turn on. When the first switch82is turned off, the main contactor76is inhibited to turn on.

A capacitor80is connected to the inverter78in parallel, thus stabilizing operation of the inverter78, while the capacitor80is connected to the second switch84and the resistor86in parallel. The second switch84and the resistor86, which are connected to the capacitor80in parallel, serve as a discharge circuit88, which discharges the capacitor80. The motor28is connected to the inverter78, which converts direct current from the main battery60into three-phase alternating current so as to supply to the motor28. Accordingly, the motor28drives.

In normal operation, as shown inFIG. 2, the first switch is turned on, while the second switch84is turned off. In discharge operation for discharging the electric charge of the capacitor80, as shown inFIG. 3, the first switch82is turned off, while the second switch84is turned on. The first switch82and the second switch84are switches that interlock with each other to turn on or off. When the first switch82is turned on, the second switch84is turned off. When the first switch82is turned off, the second switch84is turned on.

In normal operation, when the ignition switch IGNSW is turned on, the electric current is carried from the sub battery62to the coil C1and the coil C2. This excites the coil C1, thus turning on the switch SW1of the precharge relay70. Accordingly, the current from the main battery60is supplied to the capacitor80through the precharge relay70, thus precharging the electric charge in the capacitor80. The resistor72restricts the current carried to the capacitor80. Then, the excitation of the coil C2turns on the switch SW2of the main contactor76, thus enabling the supply of the electric power from the main battery60to the motor28through the inverter78. This makes the motor28ready to drive.

When the main battery60is discharged and drops its voltage, the capacitor80is discharged to reduce the voltage drop of the main battery60. When the main battery60raises its voltage, the capacitor80charges from the main battery60and raise its voltage in conjunction with the main battery60. Accordingly, the inverter78and the capacitor80, which are connected to one another in parallel, smooth voltage fluctuation of the main battery60, thus stabilizing the operation of the inverter78.

When an operator for maintenance or the like, or user (this person being referred to as operator or the like) accesses the motor drive section64(for dismounting and disassembling the motor drive section64to access its internal structure (electric circuitry)), if the capacitor80is charged, the electric charge of the capacitor80is possibly discharged. Accordingly, when accessing the motor drive section64for maintenance or the like, as shown inFIG. 3, the first switch82is turned off, while the second switch84is turned on. This connects the discharge circuit88to the capacitor80, thus discharging the electric charge accumulated in the capacitor80through the discharge circuit88.

FIG. 4is a plan view of the motor drive section64shown inFIG. 1, for illustrating its perspective view. The motor drive section64has a body case100and mounting portions102a,102b,102c, and102d, which mount the body case100to the vehicle body frame12. The mounting portions102a,102b,102c, and102dare formed with insertion holes104a,104b,104c, and104d, into which bolts B are inserted to fasten the mounting portions102a,102b,102c, and102dto the vehicle body frame12. The bolts B fasten the body case100to the vehicle body frame12.

On the upper surface of the body case100, the first switch82, the second switch84, and discharge operation unit106are disposed. The discharge operation unit106is, in this example, a manual switch to turn on one of the first switch82and the second switch84and turn off the other. This discharge operation unit106, acting as an example of a discharge operation means, is the manual switch interlocking the first switch82with the second switch in order to turn on or off.

The discharge operation unit106has a lever110, a first pushing portion112, a second pushing portion114, and a plate shaft116. The user operates the lever110. The first pushing portion pushes the first switch82to turn on. The second pushing portion pushes the second switch84to turn on. The discharge operation unit106is able to turn about the plate shaft116in a horizontal direction. The first switch82and the second switch84are biased to turn off. The first switch82is turned on when pushed by the first pushing portion112. The second switch84is turned on when pushed by the second pushing portion114.

In normal operation, the lever110of the discharge operation unit106is disposed at a position so as to cover the insertion hole104aof the mounting portion102aas shown inFIG. 4. In the normal operation, the first pushing portion112keeps the switch SW1in ON state. When the user accesses the motor drive section64, that is, when the motor drive section64is dismounted for maintenance or the like, the discharge operation unit106covers the insertion hole104aof the mounting portion102a. Thus, in order to unscrew the bolt B screwed into the insertion hole104a, the lever110of the discharge operation unit106needs a turn in the counterclockwise direction as shown inFIG. 5. When the lever110is turned in the counterclockwise direction, the first pushing portion112moves away from the first switch82to turn off the first switch82, while the second pushing portion114pushes the second switch84to turn on the second switch84. As described above, when the first switch82is turned off, and the second switch84is turned on, the discharge circuit88is connected to the capacitor80, thus discharging the electric charge from the capacitor80.

FIG. 6andFIG. 7are plan cross-sectional views of a configuration of the first switch82.FIG. 6is a plan cross-sectional view of the first switch82in OFF state.FIG. 7is a plan cross-sectional view of the first switch82in ON state. The second switch84has the same configuration as the first switch82, and therefore the second switch84will not be further described here.

The first switch82has a shaft150, an action plate156, and a switch cover158. The shaft is pushed by the first pushing portion112of the discharge operation unit106. The action plate brings a first contacting terminal152and a second contacting terminal154in contact with one another in conjunction with the push of the shaft150. The switch cover accommodates the shaft150, the first contacting terminal152, the second contacting terminal154, and the action plate156. The first contacting terminal152is connected to a wiring160, which is connected to the positive electrode of the main battery60, while the second contacting terminal154is connected to a wiring162, which is connected to the inverter78.

A biasing member164is disposed between the second contacting terminal154and the wiring162. The biasing member urges the action plate156so as to turn off the first switch82(in a direction separating the first contacting terminal152and the second contacting terminal154, and pushing the shaft150outward). As shown inFIG. 7, when the shaft150is pushed inward by the first pushing portion112of the discharge operation means106, the action plate156operates against the biasing direction of the biasing member164, thus bringing the second contacting terminal154into contact with the first contacting terminal152.

As describe above, the resistor86, which discharges the electric charge of the capacitor80for stabilizing the operation of the inverter78, and the discharge operation unit106, which manually makes the resistor86to discharge the electric charge of the capacitor80, are provided. These enable the discharge of the electric charge accumulated in the capacitor80when accessing the motor drive section64during maintenance, thus ensuring the easy accessibility to the motor drive section64as an electronic component.

The discharge operation unit106is disposed such that the motor drive section64is not accessible unless the discharge operation means106is manually operated when accessing the motor drive section64. Accordingly, it is necessarily discharged when accessing the motor drive section64.

The discharge operation unit106in this embodiment is a manual switch to connect the discharge circuit88, which includes the resistor86, to the capacitor80, thus ensuring the discharge of the electric charge of the capacitor80.

The motor drive section64is interposed between the main battery60and the motor28, and has the main contactor76, the first switch82, and the second switch84. The main contactor connects the main battery60and the inverter78of the motor drive section64. The first switch permits the main contactor76to turn on. The second switch connects the discharge circuit88to the capacitor80. The discharge operation unit106turns on one of the first switch82and the second switch84and turns off the other. Thus, when discharging the electric charge of the capacitor80, the main contactor76is turned off. This prevents the motor drive section64from driving the motor28when accessing the motor drive section64.

In the above-described embodiment, the circuit is so configured that when the ignition switch IGNSW is turned on, the current is automatically carried from the sub battery62to the coil C1of the precharge relay70and the coil C2of the main contactor76, thereby automatically turning on the precharge relay70and the main contactor76. The ECU66may control on and off of the precharge relay70(switch SW1of the precharge relay) and on and off of the main contactor76(switch SW2of the main contactor76). In this configuration, when the ignition switch IGNSW is turned on, the ECU66may turn on the precharge relay70to charge the capacitor80. Then, the ECU66may turn off the precharge relay70and turn on the main contactor76, simultaneously.

In the above-described embodiment, the discharge operation unit106is disposed at the position so as to cover the insertion hole104aof the mounting portion102afor mounting the body case100to the vehicle body frame12. In the configuration where the body case100is composed of a base portion and a cover portion (not shown), the discharge operation unit106may be disposed at a position so as to cover an insertion hole, into which the bolt for mounting the cover portion to the base portion is inserted. Accordingly, in order to open the cover of the body case100, it is necessary to operate the discharge operation unit106to unscrew the bolt, thus ensuring the discharge of the electric charge of the capacitor80.

In the above-described embodiment, the electric vehicle10is described as an exemplary hybrid motorcycle. The electric vehicle10may be an electric motorcycle. Any other configuration is possible insofar as the electric vehicle10comprises a vehicle with a motor such as motor28.

The present invention has been described with the preferred embodiments. The scope of the present invention is not limited to the above-described embodiments. Various modifications and improvements of the embodiments will become apparent to those skilled in the art. Embodiments thus modified and improved are also within the scope of the present invention according to the description of the claims. The parenthetical reference signs in claims are provided to facilitate the understanding of the present invention according to the reference signs in the accompanying drawings. Thus, the present invention is not limited to the elements with the reference signs.

REFERENCE SIGNS LIST