Abstract: A working machine includes a prime mover, a traveling pump configured to deliver hydraulic fluid at a flow rate corresponding to an angle of the swashplate, a traveling motor configured to be rotated by the hydraulic fluid delivered from the traveling pump so as to have a rotation speed shiftable between a first speed and a second speed higher than the first speed, a traveling change-over valve shiftable between a first state to set the rotation speed of the traveling motor to the first speed and a second state to set the rotation speed of the traveling motor to the second speed, an operation device, an operation valve configured to change the angle of the swashplate of the traveling pump according to operation of the operation device, an actuation valve provided upstream or downstream of the operation valve and fluidly connected to the operation valve, and a controller configured or programmed to output a control signal to control the actuation valve in such a way that, when the traveling change-over valve i

Abstract: A working machine includes a first rotation detector to detect a first rotation speed of the left traveling motor, a second rotation detector to detect a second rotation speed of the right traveling motor, and a controller to perform automatic deceleration to automatically reduce the first rotation speed and the second rotation speed both set at respective second speed stages by shifting a speed stage of each of the first rotation speed and the second rotation speed to a first speed stage that is lower than the second speed stage. During straight traveling of a machine body of the working machine, the controller determines a straight-traveling threshold serving as a deceleration threshold for judging whether to perform the automatic deceleration based on the first rotation speed or the second rotation speed.

Abstract: A working machine includes a prime mover, a hydraulic pump driven by power of the prime mover, a cooler including a cooling fan rotated by either the power of the prime mover or hydraulic fluid delivered from the hydraulic pump, and a controller configured or programmed to perform a reduction control for reducing a target fan rotation speed that is a target rotation speed of the cooling fan in response to reduction of an actual prime mover rotation speed that is an actual rotation speed of the prime mover, and to perform, after the reduction control, a restoration control for restoring the target fan rotation speed. The controller is configured or programmed to make a difference between a reduction rate of the target fan rotation speed in the reduction control and an increase rate of the target fan rotation speed in the restoration control.

Abstract: A working machine includes a controller to perform automatic deceleration to automatically reduce a first rotation speed of a left traveling motor to output a power to a left traveling device on a left portion of a machine body and a second rotation speed of a right traveling motor to output a power to a right traveling device on a right portion of the machine body by shifting a speed stage of each of the left and right traveling motors from a second speed to a first speed that is lower than the second speed. The controller is configured or programmed to determine, based on the second rotation speed, a left threshold for judging whether to perform the automatic deceleration in left pivot turn of the machine body, and to determine, based on the first rotation speed, a right threshold for judging whether to perform the automatic deceleration in right pivot turn of the machine body.

Abstract: A working machine includes a controller to perform an automatic deceleration operation to automatically decelerate from a second speed to a first speed when a value calculated based on a first traveling pressure, a second traveling pressure, a third traveling pressure, and a fourth traveling pressure becomes equal to or more than a deceleration threshold in a state where a left traveling motor and a right traveling motor are being driven at the second speed.

Abstract: A working machine includes a controller configured to determine a first deceleration threshold corresponding to each of a first traveling pressure, a second traveling pressure, a third traveling pressure, and a fourth traveling pressure, to perform automatic deceleration to reduce rotation speeds of a left traveling motor and a right traveling motor, and to judge whether to perform the automatic deceleration based on the determined first deceleration threshold, the first traveling pressure, the second traveling pressure, the third traveling pressure, and the fourth traveling pressure.

Abstract: A working machine includes a fan motor driven with hydraulic fluid, the fan motor including a first port and a second port, a bypass fluid passage connecting the first port of the fan motor and the second port to each other, a flow rate control valve provided on the bypass fluid passage to control a flow rate of the hydraulic fluid flowing in the bypass fluid passage, a drain passage configured to drain the hydraulic fluid upstream of the flow rate control valve, and an unloading valve shiftable between a full-closing position to close the drain passage and a full-opening position to open the drain passage.

Abstract: A working machine includes a prime mover, a traveling device, a traveling motor configured to output power to the traveling device, a speed shifting valve configured to shift an output speed of the traveling motor between a first speed and a second speed faster than the first speed, an actuation valve configured to change a hydraulic pressure applied to the speed shifting valve, a first fluid passage fluidly connected to the speed shifting valve so that hydraulic fluid having the hydraulic pressure to be applied to the speed shifting valve flows through the first fluid passage, a drain fluid passage fluidly connected to the first fluid passage, a brake shiftable between a braking state to brake the traveling motor and a braking releasing state to release the braking, and a controller configured or programmed to control the actuation valve and the brake, and being capable of activate a warm-up mode.

Abstract: A working machine includes a controller configured or programmed to perform an automatic deceleration for automatically decelerating a left traveling motor and a right traveling motor rotated at a second speed by shifting from the second speed to the first speed, and to determine a deceleration threshold that is used for judging whether the automatic deceleration has to be performed or not.

Abstract: A working machine includes a first traveling fluid passage connected to a first pressure-receiving portion, a second traveling fluid passage connected to a second pressure-receiving portion, a third traveling fluid passage connected to a third pressure-receiving portion, a fourth traveling fluid passage fluidly connected to a fourth pressure-receiving portion, and a connection fluid passage connecting at least two of the first, second, third and fourth pressure-receiving portions to each other. When a traveling operation member is operated, operation fluid flows to the first pressure receiving portion through the first traveling fluid passage, to the second pressure receiving portion through the second traveling fluid passage, to the third pressure receiving portion through the third traveling fluid passage, and to the fourth pressure receiving portion through the fourth traveling fluid passage.

Abstract: A working machine includes a first traveling fluid line through which operation fluid applied to a first pressure receiving portion when a traveling operation member is operated, a second traveling fluid line through which operation fluid applied to a second pressure receiving portion when the traveling operation member is operated, a third traveling fluid line through which operation fluid applied to a third pressure receiving portion when the traveling operation member is operated, a fourth traveling fluid line through which operation fluid applied to a fourth pressure receiving portion when the traveling operation member is operated, and a controller configured or programed to judge, first, second, third and fourth pilot pressures, whether the traveling operation member is operated in a direction corresponding to any of spin-turn, pivotal-turn and straight-traveling.

Abstract: A working machine includes a prime mover, a traveling pump to be driven by the prime mover to output operation fluid, a traveling motor to be driven by the operation fluid outputted from the traveling pump and to change a motor speed between a first speed and a second speed higher than the first speed, a machine body on which the prime mover, the traveling pump, and the traveling motor are arranged, a traveling switching valve to be switched between a first state allowing the traveling motor to rotate at the first speed and a second state allowing the traveling motor to rotate at the second speed, and a controller to reduce a revolving speed of the prime mover based on a traveling condition of the machine body in switching the traveling switching valve between an accelerating state to switch the traveling switching valve from the first state to the second state and a decelerating state to switch the traveling switching valve from the second state to the first state.

Abstract: A hydraulic system includes a hydraulic pump, a first hydraulic actuator, a second hydraulic actuator, a first control valve to control the first hydraulic actuator, a second control valve to control the second hydraulic actuator, the second control valve being arranged on a downstream side of the first control valve, and a discharge fluid tube in which the operation fluid flows. The hydraulic system further includes a first fluid tube in which a return fluid flows toward the second control valve. The hydraulic system further includes a second fluid tube in which a supply fluid flows toward the first hydraulic actuator, a third fluid tube coupling the first fluid tube to the discharge fluid tube, and a fourth fluid tube in which the return fluid flows toward the second fluid tube, the fourth fluid tube being connected to the first fluid tube.

Abstract: 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.

Abstract: A hydraulic system for a working machine includes a hydraulic pump to output operation fluid, a hydraulic actuator to be activated with the operation fluid, a first control valve to which the operation fluid outputted by the hydraulic pump is supplied, the first control valve being configured to control the hydraulic actuator, a second control valve to control the hydraulic actuator separately from the first control valve, a first fluid tube connecting the hydraulic pump and the first control valve, a second fluid tube branching from the first fluid tube and connecting to an input port of the second control valve, a third fluid tube connecting the first control valve and the hydraulic actuator, and a fourth fluid tube connecting to an output port of the second control valve and connecting to the third fluid tube.

Abstract: A working machine includes a machine body, a traveling device provided on the machine body, a traveling motor configured to provide power to the traveling device and to be switched between a first speed and a second speed, a traveling operation member to be operated by an operator, an operation detector to detect an operation extent of the traveling operation member, a traveling pump driven in response to the operation extent to supply operation fluid to the traveling motor, a revolution detector to detect a motor revolving speed, and a controller configured to switch the traveling motor from the second speed to the first speed when the motor revolving speed is equal to or less than a deceleration threshold, and then to switch the traveling motor from the first speed to the second speed when the motor revolving speed is equal to or greater than a return threshold.

Abstract: A hydraulic system includes a first system discharge fluid tube that discharges fluid flowing through a first supply fluid tube, a second system discharge fluid tube that discharges fluid, a first control valve, and a second control valve connected to a second supply fluid tube, the first system discharge fluid tube, and the second system discharge fluid tube, configured to be switched between: a supply position that supplies fluid from the second supply fluid tube to the first supply fluid tube; a first stop position that stops supply of fluid from the second to the first supply fluid tube and supplies fluid from the first supply fluid tube to the first system discharge fluid tube; and a second stop position that stops supply of fluid from the second to the first supply fluid tube and supplies fluid from the first supply fluid tube to the second system discharge fluid tube.

Abstract: A flow rate control valve includes a first flow line to connect to a first fluid line connected to a hydraulic actuator, a second flow line to connect to a second fluid line connected to the hydraulic actuator, a third flow line to connect to a third fluid line connected to a hydraulic pump, a fourth flow line to connect to an operation fluid tank or a fourth fluid line connected to a suction portion of the hydraulic pump, a fifth flow line to connect a first control valve and a second control valve, and a spool including a first connecting portion being configured to connect the first flow line and the third flow line at a first position and to connect the first flow line and the fifth flow line at a second position.

Abstract: A hydraulic system for a work machine includes a travel hydraulic device which changes a travel speed in accordance with switching positions of a hydraulic switch valve. A controller controls a proportional valve so as to change a pressure of an operation fluid at an increasing rate over a time while the hydraulic switch valve is switched from a first switching position to a second switching position to increase the travel speed from a first speed to a second speed, and at a decreasing rate over the time while the hydraulic switch valve is switched from the second switching position to the first switching position to decrease the travel speed from the second speed to the first speed. A magnitude of the increasing rate is different from one of the decreasing rate to output an operation fluid.

Abstract: A hydraulic system includes a hydraulic pump, an output fluid tube connected to the hydraulic pump, an operation fluid tube connected to a hydraulic device, an unload valve connected to the output fluid tube, and having: a supply position in which the operation fluid in the output fluid tube is supplied to the operation fluid tube; and a restrain position in which supply of the operation fluid to the operation fluid tube is restrained, an operation valve connected to the output fluid tube, a control fluid tube connecting the operation valve and the hydraulic device, a warmup fluid tube connecting the control fluid tube and the operation fluid tube, and a check valve provided in the warm-up fluid tube and being for allowing the operation fluid to flow from the control fluid tube side toward the operation fluid tube, and for blocking the operation fluid from flowing side from the operation fluid tube toward the control fluid tube.