A working machine includes first and second traveling pumps, an acquirer to acquire the number of revolutions and the rotation direction of each of first and second traveling motors, a determiner to, based on the acquired number of revolutions and the acquired rotation direction, determine whether a machine body is in a straight traveling state or a turn traveling state, and a controller configured or programmed to, when switching from a first state allowing rotation speeds of the first and second traveling motors to increase up to a first maximum speed, to a second state allowing the rotation speeds to increase up to a second maximum speed higher than the first maximum speed, or vice versa, is performed, reduce an amount of hydraulic fluid supply from the pumps to the motors according to the straight traveling state or the turn traveling state of the machine body.

An inching system for a vehicle having a hydrostatic transmission and an engine that drives the transmission. The transmission has a pilot pressure port with a pressure of hydraulic fluid at the pilot pressure port controlling a level of power from the transmission, a beginning of draining of the hydraulic fluid from the pilot pressure port defining an inching starting point. The system includes a brake pedal and an electrohydraulic valve coupled to the pilot pressure port of the transmission, the valve being configured to drain the hydraulic fluid at the pilot pressure port. A sensor is coupled to the pedal to detect an input from the operator, the sensor producing a signal indicative of the input from the operator. A controller receives the signal and a speed of the engine. The controller controls the electrohydraulic valve dependent upon the signal and the engine speed so that the inching starting point is unchanged regardless of the speed of the engine.

In a working machine, a controller decreases a supply amount of hydraulic fluid from a travel pump to a travel motor based on a travel state of a machine body when a speed-change instruction is issued by operating a switch. When a speed-increase operation is performed, the controller switches the travel switching valve from the first state to the second state in a prior period lasting up to when the supply amount to the travel motor starts decreasing, in a restoration period in which the supply amount to the travel motor after being decreased is being restored, or in an after-restoration period in which the supply amount has been restored.

In a working machine, a controller decreases a supply amount of a hydraulic fluid from a travel pump to a travel motor based on a travel state of a machine body when a speed-change instruction of increasing or decreasing speed is output by operating a switch, and a pressure detector detects a travel pressure that is a pressure of a hydraulic fluid delivered by the travel pump to the travel motor. In accordance with the travel pressure detected by the travel pressure detector, the controller changes a delay period lasting up to a switching timing of the travel switching valve from an output timing of the speed-change instruction of the switch.

An object of the invention is to achieve a travel speed known in the art during travelling operation, improve energy efficiency by reducing energy loss, and obtain favorable travel operability less susceptible to effects from variations in a travel load and changes in a pump delivery pressure when travelling operation is performed through operation of a travel lever over a half stroke range or less. A variable restrictor valve 80 is disposed in parallel with a flow sensing valve 50 of an engine speed sensing valve unit 13. A travel pilot pressure is adapted to act in an opening direction of the variable restrictor valve 80. The variable restrictor valve 80 is set to have a continuously increasing opening area from a full closure to a maximum with an increasing travel pilot pressure. Travel flow control valves 6d and 6e have an opening area that allows a predetermined flow rate QT required for traveling to be obtained even when a target LS differential pressure is decreased to a second specified value Pa3 when the travel lever is fully operated. In a first half of a spool stroke, the travel flow control valves 6d and 6e have an opening area approximate to an opening area of comparative example 1.

A speed-changing device (21) is provided with an input shaft (22), an output shaft (23), a planetary gear mechanism (29), a first variator (33), a second variator (34), and a controller (25). The planetary gear mechanism (29) is configured to include a carrier (29A) connected to the input shaft (22), a first sun gear (29B) connected to the first variator (33), and a second sun gear (29C) connected to the output shaft (23). The second variator (34) transmits power transmitted from the first variator (33) to the output shaft (23), or transmits power transmitted from the output shaft (23) to the first variator (33). The controller (25) changes the rotation speed of the first variator (33), thereby changing the rotation speed of the output shaft (23) in relation to the rotation speed of the input shaft (22).

The working machine includes a traveling device, a traveling motor, a hydraulic pump including a swashplate, a prime mover to drive the hydraulic pump, a first servo-cylinder to set an angle of the swashplate, a charge pump to supply pilot fluid to the first servo-cylinder, a switching valve shiftable between a traveling position to supply the pilot fluid from the charge pump to the first servo-cylinder and a neutral position to stop the pilot fluid supply to the first servo-cylinder, a switching operation member operable to select either a traveling mode or a neutral mode, and a controller to shift the switching valve between the traveling position and the neutral position. The controller holds the switching valve at the neutral position after the switching operation member is operated to select the traveling mode until a rotation speed of the prime mover becomes not less than a first predetermined rotation speed.

A method includes the steps of receiving, during a first action of an automatic adaptive loading procedure by a work machine equipped with a boom and a bucket connected to the boom, driveline information of at least one driveline component of the work machine, defining a set of control parameters on the basis of the received driveline information, and controlling position of the boom, position of the bucket, and speed of the work machine on the basis of the defined set of control parameters during a second action of the automatic adaptive loading procedure.

An excavator includes a lower travelling body; an upper turning body mounted on the lower travelling body; a hydraulic pump installed in the upper turning body; a travelling hydraulic motor that is a variable displacement type motor configured to move the lower travelling body by being driven by hydraulic oil discharged by the hydraulic pump; and a control device configured to control a motor capacity of the travelling hydraulic motor so as to be switchable between a plurality of levels. The control device switches the motor capacity to a low rotation setting upon detecting that an operation for changing a travelling direction of the lower travelling body is performed.

To provide a traveling control mechanism and a traveling control method capable of controlling a traveling mechanism taking into consideration operation contents of a remote control valve. The problem is solved by a traveling control mechanism comprising a remote control valve (21, 22, 23, 24), a pressure adjusting solenoid valve (61, 62), a setting mechanism (70), and a controller (60). The traveling mechanism (8) allows a traveling speed to be switched between a high speed and a low speed in accordance with an operation amount of the remote control valve (21, 22, 23, 24). An HST circuit (30) is provided with a pump (31, 32) and a traveling motor (33), the pump (31, 32) connects to a pilot line (41, 42, 43, 44) allowing a hydraulic oil supplied from the remote control valve (21, 22, 23, 24) to flow therethrough, a pressure sensor (45) is attached to the pilot line (41, 42, 43, 44), and a rotation sensor (65) is attached to the traveling motor (33). The controller (60) controls a pressure of the hydraulic oil supplied from the remote control valve (21, 22, 23, 24) independently of a manual operation of the remote control valve (21, 22, 23, 24), on the basis of a setting signal, a pressure signal, and a rotation speed signal. The remote control valve (21, 22, 23, 24) controls a flow rate of the hydraulic oil discharged from the pump (31, 32) by changing or keeping constant the pressure inside the pilot line (41, 42, 43, 44).