Hitachi Construction Machinery Co., Ltd.

Kcm Corporation

Noritaka Ito

Satoru Kaneko

Takashi Ikimi

Hidekazu Moriki

Kazuo Ishida

Hiroaki Yanagimoto

Yuichiro Morita

Shigeyuki Yoshihara

Hirofumi Shimada

Masatoshi Hoshino

Akinori Kamiya

Takatoshi Ooki

Satoshi Sekino

Toshio Kotaka

Toru Kikuchi

Hiroshi Utashiro

To provide a technique for reliably acquiring a required braking power during travel and for efficiently using a regenerative power generated during braking. A work vehicle calculates a regenerative power outputted from an electric motor and a target hydraulic driving power for driving a hydraulic pump, supplies the regenerative power to the generator motor operating as a motor and makes the generator motor consume the regenerative power in a case where the regenerative power is equal to or smaller than the target hydraulic driving power, and supplies the regenerative power to the generator motor operating as the motor and makes an exhaust brake consume a power equivalent to a difference between the regenerative power and the target hydraulic driving power in a case where the regenerative power is larger than the target hydraulic driving power.

Work vehicle

A hybrid type work vehicle includes a power source, a traveling unit, a hydraulic work unit, an accelerator pedal, a brake pedal, an operation lever device, and a control apparatus. The control apparatus is configured such that when the current operation state is determined to be that of an excavation work which is a combined operation of the traveling unit and the hydraulic work unit and the output power limitation signal is outputted, the control apparatus limits the output power of the traveling unit. The control apparatus is also configured to decrease the tilting angle of the hydraulic pump, such that a ratio between the output power of the traveling unit and the output power of the hydraulic work unit is maintained at a preset ratio.

Hybrid type work vehicle

An electric driving wheel type work vehicle has a traveling motor, an inverter for supplying the motor with three-phase power converted from DC power, a pre-driver circuit for supplying a gate signal to the inverter on the basis of an input PWM signal, a controller for outputting to the pre-driver circuit the PWM signal for controlling the driving of the motor, a parking brake, and a parking brake condition detector that detects the condition of the parking brake. When it is detected that the parking brake has been operated, the pre-driver circuit cuts off the output of the gate signal or the input of the PWM signal to the pre-driver circuit.

Electric driving wheel type work vehicle

A hybrid work vehicle includes a work device, a traveling drive device, a lever operation quantity detection unit, an engagement state detection unit, a pedal operation quantity detection unit, a travel state detection unit, and an engine control unit. The engine control unit controls an engine rotation rate based upon at least either the lever operation quantity or the pedal operation quantity in correspondence to either the engaged state or the non-engaged state and either the traveling state or the non-traveling state.

Hybrid work vehicle

A hybrid work vehicle includes: a work device; a traveling drive device; a lever operation quantity detection unit that detects a lever operation quantity of a control lever operated to control the work device; an engagement state detection unit that detects an engaged state and a non-engaged state of the work device; a pedal operation quantity detection unit that detects a pedal operation quantity of an accelerator pedal; a travel state detection unit that detects a traveling state and a non-traveling state of the traveling drive; and an engine control unit that controls an engine rotation rate based upon at least either the lever operation quantity or the pedal operation quantity in correspondence to either the engaged state or the non-engaged state and either the traveling state or the non-traveling state.

An electrically driven working vehicle that requiring reduced power assistance from an electrical storage device is provided. The vehicle has an engine, a generator motor connected to the engine, a generator inverter for controlling the amount of power generated by the generator motor, a traveling motor for driving the vehicle, an electrical storage device connected to the generator inverter and the traveling motor, and a forward/reverse switching device for switching the traveling direction of the vehicle. The vehicle further includes a control device for outputting to the generator inverter an instruction to increase the amount of power generated by the generator motor when the voltage of the electrical storage device is equal to or lower than a maximum voltage level and a speed signal of the traveling motor given upon switching of the forward/reverse switching device is equal to or lower than a predetermined speed.

Electrically driven working vehicle

When the total value of demanded hydraulic power and demanded traveling power is larger than the sum of the engine power that can be output by an engine () and of the discharge power that can be discharged by an electrical storage device (), the actual power of a hydraulic pump () is increased from the value at the time of demand toward the demanded hydraulic power under the constraint of a predetermined limit. While the power of the hydraulic pump is being subjected to the predetermined limit, the actual power of the traveling motor is decreased from the value at the time of demand by a value smaller than the magnitude of the predetermined limit. This prevents worsening of ride comfort attributable to the distribution of power between the hydraulic pump and the traveling motor.

A hybrid wheel loader is provided, the hybrid wheel loader achieving high work efficiency even with a short supply of power to be output relative to a vehicle power requirement. The hybrid wheel loader includes a motor generatorconnected to an engine (), a hydraulic pump () connected to the motor generator, a hydraulic actuator () driven by hydraulic oil supplied from the hydraulic pump, a travel electric motor () for driving wheels (), and an electrical storage device () connected to each of the motor generator and the electrical storage device via respective inverters (). When a total requirement power value is greater than a hybrid output upper limit value, either one of a hydraulic requirement power value Pf and a travel requirement power value Prun is limited according to an operation of the wheel loader to thereby set the total requirement power value to a value equal to, or less than, the hybrid output upper limit value.

Wheel loader

[Problem] To provide a hybrid work vehicle which is simple in configuration, good in ease of mounting on a vehicle and capable of efficiently transmitting motive power. [Solution] The hybrid work vehicle includes: an engine (); a hydraulic pump () which is driven by the engine; a work device () which is disposed at the front of the vehicle and performs work using the hydraulic pump as a drive source; a motor/generator () which generates electric power by use of the torque of the engine; and a travel drive device which causes the vehicle to travel by rotating and driving wheels by use of the electric power generated by the motor/generator. The hybrid work vehicle is steered while the vehicle bends by way of a center joint (). The travel drive device includes: a plurality of electric motors (and); and a propeller shaft () which is linked with the plurality of electric motors and transmits motive power from the plurality of electric motors to the wheels. The plurality of electric motors are disposed at the front and rear sides of the center joint with the center joint being disposed therebetween.

A construction vehicle control apparatus is provided including: a motor generator control unit () which, when regenerative electrical power generated by a motor () during regenerative braking surpasses acceptable charging electrical power of a capacitor (), drives a motor generator () using the surplus electrical power; an engine controller () which detects the rotating speed of an engine (); a motor control unit () which, if the rotating speed of the engine becomes larger than a second set value while the motor generator is being driven by the surplus electrical power, reduces regenerative torque generated by the motor; and a brake control unit () which, if the rotating speed of the engine becomes larger than the second set value while the motor generator is being driven by the surplus electrical power, increases regenerative torque generated by a hydraulic brake ().

Construction vehicle control apparatus and construction vehicle

[Problem] To provide a hybrid wheel loader capable of highly efficient and stable supply of motive power. [Solution] A hybrid wheel loader including: a front work machine () provided at the front of a vehicle; power sources including an engine () and an electric storage device; and a hybrid control device () which controls output of these power sources; characterized in that: a capacitor () is provided as the electric storage device; and the hybrid control device makes control to decrease a voltage of the capacitor in accordance with increase of energy held by the vehicle.

Growing community of inventors

Ushiku, Japan

Noritaka Ito