Electronic control unit, electric power-assisted steering device and transmission ratio-variable steering unit

• US 20050258792A1
• Filed: 05/20/2005
• Published: 11/24/2005
• Est. Priority Date: 05/21/2004
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Matsuda, Naoki, Toda, Yasuyoshi, Yamamoto, Toshihisa
• Granted Patent: US 7,106,012 B2
• Time in Patent Office: Days
• US Class Current: 318/432
• CPC Class Codes: B62D 5/008 Changing the transfer ratio between the steering wheel and the steering gear by variable supply of energy, e.g. by using a superposition gear
• CPC Class Codes: B62D 5/046 Controlling the motor
• CPC Class Codes: B62D 5/0481 monitoring the steering system, e.g. failures
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 7/48 using discharge tubes with control electrode or semiconductor devices with control electrode

Abstract

An electronic control unit for producing a sufficiently boosted voltage even when a supply voltage becomes high includes an inverter that drives switching elements and converts a DC voltage into an AC voltage, and booster means which boosts a DC voltage that is input into a voltage to lie within a voltage range in which a voltage necessary for driving the switching elements is a lower-limit value and a maximum boosted voltage is an upper-limit value, and outputs the boosted voltage to the inverter.

Claims

1. An electronic control unit comprising:

an inverter that drives the switching elements and converts a DC voltage into an AC voltage; and

booster means which boosts a DC voltage that is input into a voltage to lie within a voltage range in which a voltage necessary for driving the switching elements is a lower-limit value and a maximum boosted voltage is an upper-limit value, and outputs the boosted voltage to the inverter.

2. An electronic control unit according to claim 1, further comprising voltage monitoring means for monitoring a voltage value that is boosted, wherein the booster means discontinues the boosting when the monitored voltage becomes greater than a predetermined threshold value included in the voltage range, and effects the boosting when the monitored voltage becomes smaller than the threshold value.

3. An electric power-assisted steering device according to claim 1, wherein the electronic control unit is an electric power-assisted steering device in a vehicle in which a motor is energized and driven based on the steering operation by a driver to give a steer-assisting torque to a steering mechanism, wherein the motor is driven by the inverter.

4. An electric power-assisted steering device according to claim 3, further comprising voltage monitoring means for monitoring a voltage value that is boosted, wherein the booster means discontinues the boosting when the monitored voltage becomes greater than a predetermined threshold value included in the voltage range, and effects the boosting when the monitored voltage becomes smaller than the threshold value.

5. A transmission ratio-variable steering unit according to claim 1, wherein the electronic control unit is a transmission ratio-variable steering unit comprising an input shaft connected to the steering side, an output shaft connected to the side of the rolling wheels to be steered, and a transmission ratio-variable mechanical unit which varies the rotational angle of the output shaft relative to the rotational angle of the input shaft by energizing and driving a motor, wherein the motor is driven by the inverter.

6. The transmission ratio-variable steering unit according to claim 5, further comprising voltage monitoring means for monitoring a voltage value that is boosted, wherein the booster means discontinues the boosting when the monitored voltage becomes greater than a predetermined threshold value included in the voltage range, and effects the boosting when the monitored voltage becomes smaller than the threshold value.