Disclosed herein are hydraulic actuators and methods for the operation of actuators having variable relative pressure ratios. Further disclosed are methods for designing and/or operating a hydraulic actuator such that the actuator exhibits a variable relative pressure ratio. In certain embodiments, the relative pressure ratio of the hydraulic actuator may be dependent on one or more characteristics (such as, for example, frequency or rate of change) of an oscillating input to the hydraulic actuator.

A damper assembly includes an outer cylinder, an inner cylinder positioned at least partially within the outer cylinder, a plunger positioned at least partially within the inner cylinder and coupled to a rod, an aperture extending through the rod, an annular piston coupled to the inner cylinder, and a valve assembly. The rod is positioned at least partially within the inner cylinder and has an outer dimension that is smaller than an inner dimension of the inner cylinder. The plunger and an interior of the inner cylinder at least partially define a first chamber. The valve assembly is in fluid communication with the first chamber and a second chamber. The annular piston extends between the inner cylinder and the outer cylinder, and the annular piston, an exterior surface of the inner cylinder, and the outer cylinder at least partially define the second chamber.

A damper assembly includes an outer cylinder, an inner cylinder positioned at least partially within the outer cylinder, a plunger positioned at least partially within the inner cylinder and coupled to a rod, an aperture extending through the rod, an annular piston coupled to the inner cylinder, and a valve assembly. The rod is positioned at least partially within the inner cylinder and has an outer dimension that is smaller than an inner dimension of the inner cylinder. The plunger and an interior of the inner cylinder at least partially define a first chamber. The valve assembly is in fluid communication with the first chamber and a second chamber. The annular piston extends between the inner cylinder and the outer cylinder, and the annular piston, an exterior surface of the inner cylinder, and the outer cylinder at least partially define the second chamber.

An axle arrangement for a baler includes: a first axle with a first end and a second end, the first end being coupled with the chassis by a first leaf spring and a first hydraulic cylinder, the second end being coupled with the chassis by a second leaf spring and a second hydraulic cylinder; a second axle with a first end and a second end, the first end being coupled with the chassis by a first leaf spring and a first hydraulic cylinder, the second end being coupled with the chassis by a second leaf spring and a second hydraulic cylinder; a first hydraulic line fluidly interconnecting the first hydraulic cylinder on the first axle with the first hydraulic cylinder on the second axle; and a second hydraulic line fluidly interconnecting the second hydraulic cylinder on the first axle with the second hydraulic cylinder on the second axle.

An axle arrangement for a baler includes: a first axle with a first end and a second end, the first end being coupled with the chassis by a first leaf spring and a first hydraulic cylinder, the second end being coupled with the chassis by a second leaf spring and a second hydraulic cylinder; a second axle with a first end and a second end, the first end being coupled with the chassis by a first leaf spring and a first hydraulic cylinder, the second end being coupled with the chassis by a second leaf spring and a second hydraulic cylinder; a first hydraulic line fluidly interconnecting the first hydraulic cylinder on the first axle with the first hydraulic cylinder on the second axle; and a second hydraulic line fluidly interconnecting the second hydraulic cylinder on the first axle with the second hydraulic cylinder on the second axle.

In one aspect, a suspension control system is provided for dynamically adjusting pistons located proximal to wheels of an agricultural machine to substantially equalize distribution of weight of the machine at each wheel and/or provide a substantially constant desired orientation of the machine above a ground surface thereby protecting laterally extending sprayer booms from contacting the ground. Articulation, pitch, roll and/or machine height can be determined from piston measurements on the machine to apply such height corrections. For sprayers, this allows controlling clearance and suspension height to maintain the boom parallel to the ground to prevent damage.

A dual-mode suspension system using hydraulic dampers is disclosed. One or more dampers on each side of the four-wheel suspension system are coupled to a respective damper on the other side via a damper valve. One or more leaf springs may be arranged between the leading links coupled to some of the dampers, and trailing links coupled to other of the dampers. The suspension system may advantageously engage, lock, or partially disengage the respective dampers connected by the valve on each side of the system. Manipulating the valve to control engagement of the dampers, which may depend on the speed and related issues, provides control over whether heave motions should be separated from roll. In another embodiment, one or more single or double acting hydraulic cylinders may be used to engage dampers.

A load distribution apparatus of magnetic wheel, includes: a plurality of cylinder parts including one sides respectively connected to a plurality of magnetic wheels and an upper space portion and a lower space portion whose interiors do not communicate to each other; and a passage part which serves as a moving path of fluid and interconnects the plurality of cylinder parts. The passage part is configured to evenly distribute a load applied to the magnetic wheels by moving fluids in the upper space portion and the lower space portion in such a manner that the fluids are not mixed.

A load distribution apparatus of magnetic wheel, includes: a plurality of cylinder parts including one sides respectively connected to a plurality of magnetic wheels and an upper space portion and a lower space portion whose interiors do not communicate to each other; and a passage part which serves as a moving path of fluid and interconnects the plurality of cylinder parts. The passage part is configured to evenly distribute a load applied to the magnetic wheels by moving fluids in the upper space portion and the lower space portion in such a manner that the fluids are not mixed.

A method is provided for determining whether or not ground contact loss is imminent for a wheel of a vehicle, the vehicle including a vehicle body having a vertical extension in a vertical direction, the wheel being allowed to be subjected to a relative vertical displacement, in the vertical direction, in relation to the vehicle body, the vehicle further being such that a maximum value of a vertical displacement of the wheel relative to the vehicle body is limited to a relative vertical displacement limit, the method including determining an actual relative vertical displacement of the wheel relative to the vehicle body, determining a limit margin as the difference between the actual relative vertical displacement and the relative vertical position limit, and determining that ground contact loss is imminent for a wheel if the limit margin is within a predetermined vertical threshold range.