An articulated work vehicle with linked front and rear frames includes a joystick lever, a force imparting component, a speed sensor, and a controller. The joystick lever is configured to change a steering angle of the front frame with respect to the rear frame by operation by an operator. The force imparting component is configured to impart an assist force or a counterforce to operation of the joystick lever by the operator. The speed sensor is configured to sense speed of the work vehicle. The controller is configured to control the force imparting component so as to impart the assist force or the counterforce according to the speed sensed by the speed sensor.

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.

A modification system is provided for modifying the steering ratio for a vehicle having a tiltable telescopic boom arm (6). The vehicle has steered wheels (11), a steering wheel, and a steering transmission device serving to transmit steering movement between the steering wheel and the steered wheels (11) with a steering ratio R=Alpha/Beta. Beta is the steering angle of the wheels, and Alpha is the turning angle of the steering wheel. The system includes a sensor configured to determine a parameter relating to the telescopic arm. A control module controls the steering ratio that is configured to modify the steering ratio R as a function of the parameter relating to the telescopic arm. A wheeled vehicle is provided, fitted with such a steering ratio modification system.

The invention relates to a modification system for modifying the steering ratio for a vehicle having steered wheels (11), a steering wheel (10), and a steering transmission device (20) serving to transmit steering movement between the steering wheel (10) and the steered wheels (11) with a steering ratio R=Alpha/Beta, where Alpha is the turning angle of the steering wheel, and Beta is the steering angle of the wheels; said system comprising a device for determining the angular speed of the steering wheel. Said system comprises a module (102) for controlling the steering ratio R configured to calculate the steering ratio as a function of the angular speed of the steering wheel (10). The invention also relates to a wheeled vehicle fitted with such a steering ratio modification system.

A tracked vehicle includes a pilot control module which enables the pilot to steer the tracked vehicle using an existing joystick of the tracked vehicle. The tracked vehicle also includes a dual track drive pedal which drives the tracks of the vehicle simultaneously. The joystick is used to make steering corrections when utilizing the dual track drive pedal.

The present invention addresses the technical problem of providing an actuator which is provided to prevent leakage through a rod in a hydraulic or pneumatic cylinder-type actuator, and in which an existing sealing member may be used, and in particular, a cable (wire) may be used as a rod for solving the problem regardless of surface roughness thereof. An actuator for solving the above-mentioned problem in accordance with the present invention includes: a cylinder having an inner portion filled with a fluid and a front cover for closing a front end portion thereof; a piston displaced inside the cylinder by the fluid; a sealing member having one end portion fixed to the piston and the other end portion fixed to the front cover; and an operation member inserted in the sealing member and having one end portion fixed to the piston and the other end portion extending out of the front cover. In the present invention, due to the above-mentioned configuration, the sealing of a fluid (f) is already achieved by the sealing member, and thus, the operation member serves a moving function if only slipping relative to the sealing member in the sealing member. Accordingly, a rod or a cable does not need to move while being in close contact with the sealing member. Therefore, as in conventional arts, the present invention has merits in that a remarkable improvement is achieved in terms of wear of the sealing member, and it is not necessary to smoothly and precisely process the rod and to smoothly and hardly coat the cable.

The operability can be improved when the rotational speed of the engine is low and the working device actuator and the steering actuator are operated in a combined manner, while the configuration of prioritizing the operation of the steering actuator is maintained. A control device (70) included in a wheel loader (1) determines whether a working device (4) is in load lifting operation or not based on the pressure that is between a working device directional switching valve (44) and an orifice (45) and is detected by a pressure sensor (71), and reduces the opening area of a steering control valve (37) when determining that the rotational speed of an engine (14) detected by a rotational speed sensor (72) is equal to or less than a predetermined threshold (Ns) and a working device is in the load lifting operation.

A hydraulic pump assembly having a main pump, a charge pump and an auxiliary pump driven by a single shaft is provided. A pair of hydraulic porting members cooperates to feed and distribute hydraulic fluid between the three pump units, and a single inlet may be used to provide hydraulic fluid to the charge pump and the auxiliary pump.

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.

A controller controls a first drive source and a second drive source based on a moving speed of a motor grader measured by a speed sensor and a turning angular velocity of the motor grader measured by an IMU, to thereby independently control a rotation speed of each of a right front wheel and a left front wheel.