A ramping subsystem of a control system for a dual path electronically controlled hydrostatic transmission is used to modify the commanded rate of change of pump and motor acceleration, deceleration and direction change command (performed to command machine motion from forward to reverse or vice versa) in order to achieve desired machine performance and operator feel. Pump and motor acceleration, deceleration and direction change command rates are then further modified using scaling tables based on selected maximum machine speed using operator input device.

A ramping subsystem of a control system for a dual path electronically controlled hydrostatic transmission is used to modify the commanded rate of change of pump and motor acceleration, deceleration and direction change command (performed to command machine motion from forward to reverse or vice versa) in order to achieve desired machine performance and operator feel. Pump and motor acceleration, deceleration and direction change command rates are then further modified using scaling tables based on selected maximum machine speed using operator input device.

There is provided a working machine which is capable of vehicle speed control through accelerator pedal operation even during execution of work under a condition where engine rotational speed is maintained constant. The working machine has the normal mode for exercising vehicle speed control by controlling engine rotational speed on the basis of the amount of depression of the accelerator pedal and by controlling the swash plate of the HST pump on the basis of the engine rotational speed, and the attachment mode for exercising vehicle speed control by controlling the swash plate of the HST pump on the basis of the amount of depression of the accelerator pedal irrespective of engine rotational speed.

There is provided a working machine which is capable of vehicle speed control through accelerator pedal operation even during execution of work under a condition where engine rotational speed is maintained constant. The working machine has the normal mode for exercising vehicle speed control by controlling engine rotational speed on the basis of the amount of depression of the accelerator pedal and by controlling the swash plate of the HST pump on the basis of the engine rotational speed, and the attachment mode for exercising vehicle speed control by controlling the swash plate of the HST pump on the basis of the amount of depression of the accelerator pedal irrespective of engine rotational speed.

A working machine includes a prime mover, a traveling pump driven by a power of the prime mover to deliver operation fluid, a traveling motor rotated by the operation fluid delivered from the traveling pump to have a rotation speed stage shiftable between a first speed stage and a second speed stage higher than the first speed stage, a traveling switching valve shiftable between a first state where the rotation speed stage of the traveling motor is set to the first speed stage and a second state where the rotation speed stage of the traveling motor is set to the second speed stage, an actuation valve configured to change a pilot pressure of a pilot fluid to control a flow of operation fluid delivered from the traveling pump, and a controller configured to control the pilot pressure of the pilot fluid output from the actuation valve so that a value of the pilot pressure differs depending on whether the set rotation speed stage of the traveling motor is the first speed stage or the second speed stage.

A method teaches a control function, preferably a characteristic curve, of a hydrostatic motor of a traction drive of a work machine when in drive mode. The traction drive is provided with the hydrostatic motor and a hydrostatic pump, which is hydraulically connected to the hydrostatic motor. The method includes setting a pivot angle of the hydrostatic motor while taking into account a desired velocity of the work machine when in the drive mode, and checking whether predefined conditions are met. If the predefined conditions are met and a current velocity differs from the desired velocity, the method includes correcting the control function of the hydrostatic motor by taking into account a difference between the desired velocity and the current velocity. At least one value of the corrected control function of the hydrostatic motor is taught during the correcting.

A control system for a vehicle uses one or more inputs of a velocity request, a brake request, a speed request, travel direction indication, engine speed, and vehicle speed to determine a control strategy for a continuously variable transmission. A target engine speed is selected based upon the inputs, and the engine and continuously variable transmission ratio are controlled to achieve the target engine speed while controlling the vehicle according to the inputs. In some embodiments, the control strategy further selects the target engine speed according to accessory system demands, such as a hoist or lift system.

A power transmission device includes an input shaft, an output shaft, a differential device, a continuously variable transmission unit, and a control device. The differential device includes a first rotation element connected to the input shaft, a second rotation element connected to the output shaft, and a third rotation element. The continuously variable transmission unit includes a conversion unit configured to convert rotational power of the third rotation element into an other power, and a reconversion unit configured to reconvert the converted other power into the rotational power and supply the reconverted rotational power to the output shaft. The control device includes a continuously variable transmission control unit configured to generate a control signal of the continuously variable transmission unit such that the other power generated by the conversion unit exceeds the other power input to the reconversion unit.

A working vehicle includes: a vehicle body provided with a traveling device; a hydraulic pump including a swashplate configured to change an output of the hydraulic pump according to a swashplate angle; a traveling motor including an output shaft having a rotation speed variable according to the output of the hydraulic pump and capable of transmitting power of the output shaft to the traveling device; an angle detector configured to detect the swashplate angle that is an angle of the swashplate; and a swashplate control unit configured to control the swashplate angle on the basis of control information relating to control of the swashplate angle and an actual swashplate angle that is the swashplate angle detected by the angle detector.

A work vehicle includes an engine, a speed changing apparatus that includes a hydrostatic stepless speed changing mechanism and is configured to subject motive power transmitted from the engine to speed changing and output the motive power, a travelling apparatus configured to travel on the motive power received from the speed changing apparatus, a speed detector configured to detect a speed of the travelling apparatus, a pressure detector configured to detect a hydraulic pressure in a closed circuit of the hydrostatic stepless speed changing mechanism, and a controller.