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 is shifted from the second state to the first state, a value of the control signal is reduced from a set value to a mitigation value less than the set value and then restores to the set value. The controller is configured or programmed to reduce the value of the control signal from the set value to the mitigation value for a mitigation period in such a way that a first reduction rate that is a rate of reducing the value of the control signal for a first part of the mitigation period between a start point thereof and an intermediate point thereof larger than a second reduction rate that is a rate of reducing the value of the control signal for a second part of the mitigation period between the intermediate point thereof and an end point thereof.

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.

In a working machine, a traveling pump is driven by a prime mover to rotate a traveling motor by fluid therefrom. The traveling motor has a rotation speed shiftable between a lower first speed and a higher second speed. A traveling change-over valve is shiftable between a first state where the rotation speed of the traveling motor is set to the first speed and a second state where the rotation speed of the traveling motor is set to the second speed. A controller performs a shock-mitigation for reducing a rotation speed of the prime mover when the traveling change-over valve is shifted from the second state to the first state. The controller determines a reduction amount of rotation speed of the prime mover reduced by the shock mitigation based on a difference between a target rotation speed of the prime mover and an actual rotation speed of the prime mover.

A working machine includes a prime mover, a traveling pump driven by power of the prime mover to deliver hydraulic fluid, a traveling motor rotated by the hydraulic fluid delivered from the traveling pump, an operation valve configured to change a pilot pressure of pilot fluid output therefrom to the traveling pump according to operation of an operation member, an actuation valve to be activated according to a control signal so as to change a primary pressure supplied to the operation valve, a controller to perform setting of the control signal to be output to the actuation valve, and a pressure detection device to detect a secondary pressure output from the operation valve. The controller includes a setting change unit to change, based on the primary pressure and the secondary pressure, the setting of the control signal to be output to the actuation valve.

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.

Power machines, power sources for power machines, and methods which provide a hydraulic signal from a hydraulic system, through the swivel joint or swivel, to control a tensioning cylinder coupled to the undercarriage without requiring a modification to the swivel. In exemplary embodiments, the same hydraulic signal provided to at least one other hydraulic component on the undercarriage to control another machine function is also provided to control one or more tensioning cylinders. For example, exemplary disclosed embodiments provide the same hydraulic signal to tension a tensioning cylinder as is provided to shift one or more two-speed drive motors. This prevents or reduces the likelihood of de-tracking without requiring a change or redesign of the swivel.

A shovel includes a traveling body, an upper turning body turnably provided on the traveling body, an attachment including a boom, an arm, and a bucket and attached to the upper turning body, and a processor. The processor is configured to correct the motion of the attachment in such a manner as to control a slip of the traveling body toward the back in the extension direction of the attachment.

A wheel loader configured to reduce a sudden change in vehicle speed caused by an erroneous determination of a raising operation of a lift arm is provided. A wheel loader 1 includes an engine 3, a variable displacement type HST pump 41, a variable displacement type HST motor 42 coupled to the HST pump 41 in a closed circuit, a hydraulic pump for working device 43, a forward/reverse selector switch 62 for switching a forward movement and a backward movement of a vehicle body, a depression amount sensor 610 that detects a depression amount of an accelerator pedal 61, a pressure sensor 73 that detects a discharge pressure Pa of the hydraulic pump for working device 43, and a controller 5. The controller 5 determines whether a specific condition to identify an upward movement of a lift arm 21 during a forward travel of the vehicle body based on a forward/reverse switching signal, the depression amount of the accelerator pedal 61, and the discharge pressure Pa detected by the pressure sensor 73. When the specific condition is satisfied, the controller 5 controls a displacement volume of the HST motor 42 according to an increase of the discharge pressure Pa, so as to limit the vehicle speed.

A travel control device is provided with hydraulic pumps of a variable capacity type that are driven by an engine; hydraulic motors that are driven by discharged oil from the hydraulic pumps; traveling devices that are rotation-driven by the hydraulic motors; a travel operation lever that is operated so as to instruct a traveling operation; a first control valve for generating a charged hydraulic pressure by adjusting the discharged oil from a charge pump and a second control valve for generating a capacity control hydraulic pressure in accordance with the operation of the travel operation lever. The first control valve is designed to pressure-adjust and generate a charged hydraulic pressure in accordance with the rotation speed of the engine, and the hydraulic pump is subjected to a variable capacity control process by a capacity control hydraulic pressure that is pressure-adjusted and generated by the second control valve.

A method for automatically controlling vehicle speeds of a track-based work vehicle may include monitoring, with a computing device, a load transmitted through a pivot pin of a track assembly of the work vehicle and determining, with the computing device, a speed limit setting for the work vehicle based on the monitored load, wherein the speed limit setting is associated with maintaining an operating temperature of a track of the track assembly below a predetermined temperature threshold. In addition, the method may include automatically limiting, with the computing device, a vehicle speed of the work vehicle based on the determined speed limit setting.