Abstract: A piston ring (10) for forming a seal between a piston (26) and piston housing (28). The piston ring (10) has first and second orthogonal axes (12, 14) and a body portion (18) which is resiliently deformable in the direction of the first axis (12) and is substantially rigid in the direction of the second axis (14).

Abstract: A hydraulic machine has a gear wheel (2) with outwardly extending teeth and a gear ring (4) with inwardly extending teeth formed by rollers each of which is supported in a pocket (8) in the gear ring, and pressurized spaces are formed between the gear wheel and the inwardly extending teeth. To keep the wear of the machine small, each pocket (8) has at least two different radii (R1, R2, Rn) whereby a radius (R2, Rn) at a smaller displacement from the edge (12) of the pocket is larger than a radius (R1) at a larger displacement from the same edge (12) of the pocket (8).

Abstract: The invention relates to a hydraulic machine comprising a housing section with a housing, a commutation section and a gear wheel section, the gear wheel section comprising a gear wheel set with an internally toothed gear ring and an externally toothed gear wheel, which engage each other and form working chambers that are connected to at least one inlet connection and at least one outlet connection via the commutation section that comprises a rotary slide valve and a valve plate. It is endeavoured to provide such a hydraulic machine that requires only little space. For this purpose, a sealing is arranged between the rotary slide valve and the housing.

Abstract: The invention concerns a rotation angle sensor, in particular a steering angle sensor (1) for a steering unit, with a housing (2) comprising an exterior (8), a transmitter (7) arranged in a sensor chamber in the housing (2) to perform rotary movements around a rotation axis, and a stationary receiver interacting with the pick-up sensor (7). It is endeavoured to make such steering angle sensors fit for rough environmental conditions. For this purpose, the sensor chamber is connected to the exterior (8) via at least one free space (16).

Abstract: A method of operating a vehicle with a hydrostatic circuit. The method includes providing a hydrostatic circuit having first and second hydraulic kits that are fluidly connected to one another by first and second fluid lines. A by-pass valve is placed between the first and second hydraulic lines and is controlled in order to actuate the by-pass valve when certain predetermined conditions are present in order to relieve pressure within the hydrostatic circuit.

Abstract: An axial piston hydraulic device. The device has a housing that uses a servo piston in order to control the displacement of a swashplate within the device. By using a servo member disposed within a cavity of an end cap on the housing the axial piston hydraulic device is able to provide three operating positions depending on the angle of the swashplate.

Abstract: A hydrostatic transmission having a hydraulic pump that is fluidly connected to a hydraulic motor. The transmission also has a pressure control valve that has first and second stages and is fluidly connected to the hydraulic pump. By utilizing the pressure control valve when the first stage of the pressure control is at a minimum pressure the second stage determines the minimum charge pressure setting for the hydrostatic transmission.

Abstract: A hydraulic machine has a gear wheel (2) with outwardly extending teeth and a gear ring (4) with inwardly extending teeth formed by rollers each of which is supported in a pocket (8) in the gear ring, and pressurized spaces are formed between the gear wheel and the inwardly extending teeth. To keep the wear of the machine small each pocket (8) has at least two different radii (R1, R2, Rn) whereby a radius (R2, Rn) at a smaller displacement from the edge (12) of the pocket is larger than a radius (R1) at a larger displacement from the same edge (12) of the pocket (8).

Abstract: A hydromechanical transmission having a self actuating clutch assembly. The self-actuating clutch assembly comprises a first and second gear clutching elements and a shaft clutching element that engages a shaft. The shaft clutching element is a cone clutch that is actuated by a ball element that is biased towards the shaft clutching element by a spring element that is disposed through the shaft.

Abstract: A method of manufacturing a circuit board assembly for a controller. The method includes providing first and second printed circuit boards wherein the first printed circuit board has a plurality of copper pads containing slots therein that correspond to a plurality of power tabs in the second printed circuit board. The power tabs are then slid into the slots and the tabs are flooded with copper. At this time the power tabs are soldered within the slots to provide an electrical connection between the first and second printed circuit boards that allows for the transfer of current between the boards of more than three amps.

Abstract: A bent axis hydromodule that utilizes a bearing carrier assembly between the trunnion of a yoke and the frame of the bent axis hydromodule. The bearing carrier receives the trunnion and is secured to the frame by at least one fastening element that extends axially perpendicular to the trunnion axis that causes the fastening element preload force to be in the same direction as primary loading of that joint.

Abstract: The invention concerns a brake valve arrangement of a vehicle having a trailer coupling and at least one controllable hydraulic consumer, with a brake valve (27). It is endeavored to provide a similar embodiment of a vehicle with such a brake valve arrangement. For this purpose, the brake valve (27) is combined with at least one control valve (11, 12) controlling the hydraulic consumer into forming a valve block (10) having several valve modules.

Abstract: The invention concerns a hydraulic steering arrangement (1) with a supply connection arrangement (P, T), a working connection arrangement (A, B) connectable to a steering motor (5), a steering unit (6) located between the supply connection arrangement (P, T) and the working connection arrangement (A, B), and a steering valve (14) whose outlet is connected to the working connection arrangement (A, B). It is endeavoured to keep the load of such a steering arrangement small. For this purpose, the steering unit (6) is made as an open-center steering unit, an inlet (20) of the steering valve (14) being connected to a pressure supply arrangement (22) that can be activated by an activation of the steering valve (14).

Abstract: A hydraulic actuator for a hydraulic servomotor 4 is disclosed. The hydraulic servomotor 4 has a first chamber 5 and a second chamber 6 associated therewith. The hydraulic actuator is connected to a fluid source 2 and a fluid drain 3, and it comprises a valve assembly arranged between the fluid source 2 and the fluid drain 3 to control fluid pressures in the chambers 5, 6. At least one auxiliary valve 11 is fluidly connected between the valve assembly and the fluid drain 3, said auxiliary valve(s) 11 being of a kind which is normally closed in a de-energized state. In the case of a power cut off the auxiliary valve(s) 11 will close, thereby preventing fluid flow from the valve assembly towards the fluid drain 3. This causes a servomotor piston member 12 to be hydraulically locked in its instantaneous position, thereby locking the hydraulic servomotor 4. The valve assembly may be designed without taking the locking function into consideration.

Abstract: A roller vane pump that uses slippers on its rollers to create multiple seals. The roller vane pump has a fixed cam ring that has a rotor within. The rotor has openings that receive rollers that rotate about the inside of the cam ring. Each roller has a slipper rotatably connected thereto. The use of the slipper allows multiple seals to be created between the slipper, the rollers, and the cam ring and additionally allows for the roller vane pump to rotate clockwise or counterclockwise without the changing of parts.

Abstract: A control system for a hydraulic servomotor (13) is disclosed. The control system comprises an electro hydraulic actuator (2) comprising a number of valves (9, 10, 11, 12, 18) for controlling fluid flows, a main control module (1), and one or more connectors. The control system further comprises at least one extension control module (3) comprising one or more connectors. Finally, the control system comprises means (6) for communicating signals between the main control module (1) and each of the extension control module(s) (3). Since the main control module (1) and the extension control module(s) (3) are able to communicate signals, it is possible to provide signals to/from the main control module (1) via an extension module (3), thereby in effect providing additional connectors to the main control module (1). Thereby the main control module (1) may be able to perform additional functions as compared to similar prior art control modules.

Abstract: The invention concerns a hydraulic steering with a steering initiator, a steering unit with feedback properties, which can be activated by the steering initiator, the steering unit having a supply connection arrangement with a pressure connection (P) and a tank connection (T) and a working connection arrangement with two working connections (L, R), an auxiliary-force operated steering valve, which is located in parallel with the steering unit between the supply connection arrangement (P, T) and the working connection arrangement (L, R), and a feedback suppressing device, which is active, when the steering valve is active. It is endeavoured to find a simple manner of ensuring the priority of the steering initiator over the steering valve. For this purpose, the steering initiator interacts with an activation sensor, which deactivates the feedback suppressing device on an activation of the steering initiator.

Abstract: The invention concerns a hydraulic steering with a steering initiator, a steering unit with feedback properties, which can be activated by the steering initiator, the steering unit having a supply connection arrangement with a pressure connection (P) and a tank connection (T) and a working connection arrangement with two working connections (L, R), an auxiliary-force operated steering valve, which is located in parallel with the steering unit between the supply connection arrangement (P, T) and the working connection arrangement (L, R), and a feedback suppressing device, which is active, when the steering valve is active. It is endeavoured to find a simple manner of ensuring the priority of the steering initiator over the steering valve. For this purpose, the steering initiator interacts with an activation sensor, which deactivates the feedback suppressing device on an activation of the steering initiator.

Abstract: A hydraulic machine is disclosed with an externally toothed gear wheel (3) and an internally toothed ring, the gear wheel (3) and the ring together forming pressure pockets, which expand and compress during operation, the gear wheel (3) having recesses (22-25), which form part of a secondary control system. The machine should be designed to operate in a simple manner with little wear. To achieve this, the gear wheel (3) is made as a sintered element, in which the recesses (22-25) are sintered.

Abstract: A three position servo system. The servo system has a servo housing that has first and second control ports disposed therein in a cavity in fluid communication with the first and second control ports. A servo piston having at least one pressure chamber disposed therein is then used to communicate the pressure within the first and second ports into the first end of the cavity. Thus, when pressure is applied below a threshold pressure to both ports a first position is achieved, when pressure is applied above the threshold pressure in only one port a second position is achieved, and when pressure is applied above the threshold pressure in both ports a third position is achieved. Therefore, the servo system provides three different operating positions.