In a self-propelled construction machine (1), in particular slipform paving machine, comprising a machine frame (2), at least three travelling devices (14), wherein the travelling devices (14) are each connected to the machine frame (2) by means of lifting columns (12), wherein at least two of the at least three travelling devices (14) are steerable by means of one each steering drive (6), wherein the respective steering drive (6) comprises at least one first part (10), which is connected to the respective travelling device (14), and one second part (16), which is connected to the respective lifting column (12),
it is provided that the steering drive (6) comprises at least one first toothed rack (22), wherein the first toothed rack is movable by means of at least one first linear drive means (26), wherein teeth of the at least one toothed rack engage with teeth of at least one toothed wheel (17), and the toothed wheel is thus rotatable by means of the movement of the toothed rack.

A self-centering double ended hydraulic steering cylinder that uses no electronics and a method of making the same. The self-centering double ended hydraulic steering cylinder has an elongated housing having end caps at opposing ends of the housing, wherein first and second rod portions are slidably disposed through the end caps. A piston is slidably disposed within the housing, the first and second rod portions extending from the piston, the piston defining first and second hydraulic fluid chambers within the housing. On each opposing end cap is a coiled spring for urging the piston toward a neutral position with the housing. A miniscule passage is formed into the piston so that hydraulic fluid flow through the piston that allows the springs to push the piston back to the neutral position.

A self-centering double ended hydraulic steering cylinder that uses no electronics and a method of making the same. The self-centering double ended hydraulic steering cylinder has an elongated housing having end caps at opposing ends of the housing, wherein first and second rod portions are slidably disposed through the end caps. A piston is slidably disposed within the housing, the first and second rod portions extending from the piston, the piston defining first and second hydraulic fluid chambers within the housing. On each opposing end cap is a coiled spring for urging the piston toward a neutral position with the housing. A miniscule passage is formed into the piston so that hydraulic fluid flow through the piston that allows the springs to push the piston back to the neutral position.

A work machine, includes steering cylinders that drive a front frame with respect to a rear frame. A directional control valve changes a supply amount of hydraulic fluid to the steering cylinders. A steering wheel operates the directional control valve. A variable capacity pump discharges the hydraulic fluid to the directional control valve. Cylinder stroke sensors are provided for detecting the turning angle of the front frame with respect to the rear frame. A controller reduces the discharge flow rate of the variable capacity pump on the basis of the detection values of the cylinder stroke sensors.

A work machine, includes steering cylinders that drive a front frame with respect to a rear frame. A directional control valve changes a supply amount of hydraulic fluid to the steering cylinders. A steering wheel operates the directional control valve. A variable capacity pump discharges the hydraulic fluid to the directional control valve. Cylinder stroke sensors are provided for detecting the turning angle of the front frame with respect to the rear frame. A controller reduces the discharge flow rate of the variable capacity pump on the basis of the detection values of the cylinder stroke sensors.

In a power steering system employing an end of travel system including valve actuating rings disposed about a Pitman arm shaft, a device is provided for setting the positions of the rings on the shaft. The device includes a fixed member positioned about, and fixed against movement along, a longitudinal axis perpendicular to the shaft's rotational axis and a movable member that moves along the longitudinal axis relative to the fixed member. The movable member defines a pin at one end configured for engagement with the circumferential ends of the actuating rings. A positioning force applied to one of the members causes the movable member to move between set and reset positions in which the pin engages corresponding ends of the actuating rings during rotation of the shaft and a running position in which the pin remains disengaged from the ends of the actuating ring during rotation of the shaft.

In a power steering system employing an end of travel system including valve actuating rings disposed about a Pitman arm shaft, a device is provided for setting the positions of the rings on the shaft. The device includes a fixed member positioned about, and fixed against movement along, a longitudinal axis perpendicular to the shaft's rotational axis and a movable member that moves along the longitudinal axis relative to the fixed member. The movable member defines a pin at one end configured for engagement with the circumferential ends of the actuating rings. A positioning force applied to one of the members causes the movable member to move between set and reset positions in which the pin engages corresponding ends of the actuating rings during rotation of the shaft and a running position in which the pin remains disengaged from the ends of the actuating ring during rotation of the shaft.

A work vehicle includes an axle frame extending in a left-right direction, a cylinder coupled to the axle frame, and a first supply conduit connected to the cylinder and configured to supply hydraulic fluid to the cylinder. The first supply conduit is fixed to the axle frame.

A work vehicle includes an axle frame extending in a left-right direction, a cylinder coupled to the axle frame, and a first supply conduit connected to the cylinder and configured to supply hydraulic fluid to the cylinder. The first supply conduit is fixed to the axle frame.

A hydraulic system for controlling a pair of steerable caster wheels includes a left steering command valve, a right steering command valve, and a rear steering control valve. A supply pressure fluid circuit interconnects a pressure source and the rear steering control valve. A command valve supply fluid circuit interconnects the rear steering control valve with both the right steering command valve and the left steering command valve. A left side steering fluid circuit interconnects a left side actuator and the left steering command valve. A right side steering fluid circuit interconnects a right side actuator and the right steering command valve. A fluidic tie rod fluid circuit interconnects both the left side actuator and the right side actuator with the rear steering control valve. A tank return fluid circuit interconnects the rear steering control valve, the left and right steering command valves, and a tank.