Working machine

A working machine comprising:

• a prime mover;
• a travel pump driven by power of the prime mover to deliver a hydraulic fluid;
• a travel motor rotated by the hydraulic fluid delivered by the travel pump;
• a machine body where the prime mover, the travel pump, and the travel motor are provided;
• a travel switching valve switchable to a first state in which a rotation speed of the travel motor is capable of being increased up to a first maximum speed, and to a second state in which the rotation speed of the travel motor is capable of being increased up to a second maximum speed that is greater than the first maximum speed;
• a travel operation device including an operation valve operable to change a pressure of a hydraulic fluid to operate the travel pump in accordance with an operation of an operation member;
• a controller configured or programmed to decrease a supply amount of a hydraulic fluid from the travel pump to the travel motor based on a travel state of the machine body when performing either one of a speed-increase operation of switching the travel switching valve from the first state to the second state and a speed-decrease operation of switching the travel switching valve from the second state to the first state;
• a switch operable to output a speed-change instruction such as to cause the controller to perform either the speed-increase operation or the speed-decrease operation;
• and
• at least one travel pressure detector which is at least one pressure detector connected to a fluid passage connecting the travel pump and the travel motor to each other and configured to detect a pressure in the fluid passage as a travel pressure that is a pressure of the hydraulic fluid delivered by the travel pump to the travel motor, wherein
• in accordance with the travel pressure detected by the at least one travel pressure detector, the controller changes a delay period lasting up to a switching timing of switching the travel switching valve from an output timing of outputting the speed-change instruction from the switch;
• the at least one travel pressure detector includes a first travel pressure detector to detect, a forward-travel-directional travel pressure that is a pressure of the hydraulic fluid supplied from the travel pump to the travel motor when the travel motor rotates in a normal direction to cause forward travel of the machine body, and a second travel pressure detector to detect a rearward-travel-directional travel pressure that is a pressure of the hydraulic fluid delivered from the travel motor to the travel pump when the travel motor rotates in the normal direction, and
• the controller, when performing the speed-increase operation or the speed-decrease operation, changes the delay period in accordance with a difference between the forward-travel-directional travel pressure detected by the first travel pressure detector and the rearward-travel-directional travel pressure detected by the second travel pressure detector.

A working machine, comprising:

• a prime mover;
• a travel pump driven by power of the prime mover to deliver a hydraulic fluid;
• a travel motor rotated by the hydraulic fluid delivered by the travel pump;
• a machine body where the prime mover, the travel pump, and the travel motor are provided;
• a travel switching valve switchable to a first state in which a rotation speed of the travel motor is capable of being increased up to a first maximum speed, and to a second state in which the rotation speed of the travel motor is capable of being increased up to a second maximum speed that is greater than the first maximum speed;
• a travel operation device including an operation valve operable to change a pressure of a hydraulic fluid to operate the travel pump in accordance with an operation of an operation member;
• a controller configured or programmed to decrease a supply amount of a hydraulic fluid from the travel pump to the travel motor based on a travel state of the machine body when performing either one of a speed-increase operation of switching the travel switching valve from the first state to the second state and a speed-decrease operation of switching the travel switching valve from the second state to the first state;
• a switch operable to output a speed-change instruction such as to cause the controller to perform either the speed-increase operation or the speed-decrease operation;
• and
• at least one travel pressure detector which is at least one pressure detector connected to a fluid passage connecting the travel pump and the travel motor to each other and configured to detect a pressure in the fluid passage as a travel pressure that is a pressure of the hydraulic fluid delivered by the travel pump to the travel motor, wherein
• in accordance with the travel pressure detected by the at least one travel pressure detector, the controller changes a delay period lasting up to a switching timing of switching the travel switching valve from an output timing of outputting the speed-change instruction from the switch;
• the working machine further includes a gradient detector which is a sensor to detect a pitch angle of the machine body,
• during forward or rearward travel of the machine body,
• if the pitch angle detected by the gradient detector is a positive value, the controller corrects the delay period so that the delay period is decreased in accordance with a magnitude of the pitch angle, and
• if the pitch angle detected by the gradient detector is a negative value, the controller corrects the delay period so that the delay period is increased in accordance with the magnitude of the pitch angle.