Abstract: A method of operating a transmission of a vehicle. The method includes determining an open loop ratio percentage from an engine RPM input signal and a brake input signal using a first algorithm. Determining a closed loop ratio percentage from the engine RPM input signal, a vehicle RPM input signal and a throttle input signal using a second algorithm. Summing the open loop percentage and closed loop ratio percentage to calculate a ratio command percentage that is used to sum with a swashplate input to actuate a swashplate positioner and operate the transmission.

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.

Abstract: A method of cooling a radiator in an internal combustion engine wherein a plurality of fan assemblies is provided. Specifically, each fan assembly has a housing with an interior containing a fan blade and an exterior having six sides to form a hexagonal perimeter. The fan assemblies are then arranged side by side to form a cluster of fan assemblies in order to maximize the amount of fan assemblies that may be provided on an enclosure. The cluster of fan assemblies is then placed adjacent to a radiator to control the air flow over the radiator in order to cool the engine.

Abstract: An electronic traction control system for a vehicle having multiple hydraulic driven wheels includes a plurality of digital displacement pumps, a plurality of drive systems having counterbalance valves and motors used to drive wheels, and electronic flow control valves used in association with each drive assembly. Additionally the system has a steering mechanism that is electrically connected to a digital sensor and a proportional sensor that sends signals to a system controller that operates the functioning of the digital displacement hydraulic pumps.

Abstract: A relief valve assembly. The relief valve assembly has a housing that houses a sleeve element that surrounds a spool that has a spring guide disposed therein and is biased away from the spool by a spring. A fluid flow path is created from a valve exit of the assembly through the sleeve and spool via a series of openings, grooves and orifices in at least one position of the relief valve assembly. The fluid flow path acts to reduce pressure rise rate.

Abstract: A holddown pin mechanism for hydraulic power units is a ball guide with a cylindrical flat base having a central opening, a plurality of spaced elongated holddown pins have one end rigidly secured to one side of said ball guide. The pins extend outwardly at right angles from the side of said washer to which they are secured. The holddown pin mechanism is placed in a hydraulic cylinder block having a center bore, with the pins extending into holes in the block. A flat washer on a shaft extending through the block engages the free ends of the pins.

Abstract: An axle driving apparatus which has a housing and a hydrostatic transmission therein separate from the housing with fluid conduits in a center section connected to hydrostatic rotatable cylinder blocks operatively connected to axle shafts, the improvement involving check valves associated with the fluid conducting conduits and including check valve balls to affect fluid flow through the conduits and being positioned to move in a vertical path in a direction at right angles to the axes of the axle shafts, and a movable bypass arm mounted in the housing and movable to open or close the fluid conduits.

Abstract: The invention relates to an axial piston engine with a filling pump integrated in a receiving bore of the axial piston engine, which filling pump comprises a gerotor set with an externally toothed inner ring and an internally toothed outer ring and also an inner thrust plate and an outer thrust plate. The two thrust plates enclose the gerotor set between them and, on their surfaces facing away from the gerotor set, are in each case supported via a pressure field seal, which surrounds the pressure field regions formed in the thrust plates, in such a way on the housing walls axially enclosing the filling pump that lateral play in the form of axial mobility of the filling pump is guaranteed.

Abstract: A vane-type fluid displacement unit having a housing, a drive shaft extending through the housing, a rotor secured to the drive shaft and disposed within the housing, the rotor having at least one non-smooth top or bottom surface, and at least one vane secured to the rotor.

Abstract: A valve arrangement in a hydraulic circuit comprises a longitudinal duct 3 and a transverse duct 2. A throttle slide 10 can be displaced in the direction of the longitudinal duct 3. Arranged in the throttle slide 10 is a valve piston 25, by means of which the flow through the hollow throttle slide 10 can be enabled or blocked. The flow of hydraulic fluid takes place through two groups of passage holes 33a, 35a, which are arranged in the throttle slide 10. The interaction of pressure and flow direction of the hydraulic fluid, and also the restoring force of a slide spring 20 and a piston spring 30, achieves a situation where hydraulic fluid can flow through the valve arrangement in both directions but that a throttling action occurs only when the hydraulic fluid flows from the transfer duct 2 to the longitudinal duct 3 under increased pressure.

Abstract: In the housing 1 of a hydraulic machine, the pressure Pi acts in the chamber 2. For this purpose, a passage opening 4 is provided, which is formed as a valve seat 5. A valve body 6 can be displaced longitudinally in the housing 1 and forms a pressure-tight spring chamber for an inner valve spring 21. The spring chamber is connected to the chamber 2 via a pressure equalizing hole 9. The prestress of the inner valve spring 21 can be set by means of a setting screw 18. In addition, there is an outer valve spring 22. Both the valve springs load the valve body 6 with the effect of closing it. The pressure equalizing valve described combines a compact design with an advantageous flow characteristic. When a maximum value of p1 is reached, the valve body 6 lifts off the valve seat 5 and hydraulic fluid from the chamber 2 flows away via the valve chamber 3.

Abstract: A transmission has an HMT which is in parallel with an HST both driving two planetaries which are used for forward/reverse and for differential steer. A two or three mode HMT is created by having a first HST in parallel with two or three mechanical power paths defined by separate clutches. One clutch has a speed reversing gear to produce reverse output speed. A four-element planetary sums the parallel flow and delivers variable speed and torque to two output shafts. The differential steer is created by two planetaries connected with the outputs of the HMT and a second HST. The planetaries have a speed reversing gear on one power path connection. The second HST controls the differential speed between the output shafts by adding speed to one and subtracting speed from the other.

Abstract: A dual check and high pressure relief valve that is able to perform the function of a hydrostatic high pressure relief valve and a check valve. The new valve has two poppets separated by a spring that are within two seats within a guide and secured by a plug. By adjusting the seats the relief pressure setting is set. The dual check and high pressure relief valve has three separate passageways that allow fluid flow between different combinations of the passages depending upon the function desired within the hydrostatic circuit. A dashpot is also included between the two poppets to provide positive dampening of the system.

Abstract: A combination of a bull nose type and slipper type axial piston pumps. The pseudo slipper axial piston pump has an elongated piston body with a bore disposed therethrough. The bore has a spring within to create a hold down mechanism. Swivelably connected to the piston body is a pseudo slipper that engages an anti-frictional thrust bearing having first and second race elements in parallel relation with a bearing element therebetween. The anti-frictional thrust bearing then controls the angle of the swashplate.

Abstract: A bent axis hydrostatic module, comprising: a frame, a pair of parallel laterally spaced shafts rotatably supported by the frame and directed outwardly from the frame in the same direction. Two yokes are pivotally mounted about parallel axes on the frame. A hydrostatic power unit is swingably carried by each yoke, and each hydrostatic power unit being operatively connected to one of the shafts to rotate the same. A pair of system pressure conduits in the frame with each of the pressure conduits are fluidly connected to each of the cylinder blocks. A control system is provided for pivoting the yokes including means for independently pivoting the yokes about parallel axes.

Abstract: An electronic transmission control system that can achieve a transmission ratio based on the operator inputs and the current vehicle operating conditions. The transmission constantly connects the engine to the load, and the transmission ratio is only varied by a change in command from the present invention. The transmission's mechanical function is solely to vary the ratio between its input and output. In using the present invention, an operator must select an operating mode, either automatic or manual, using a two-position switch. While in the automatic mode, the present invention determines the vehicle speed by considering the position of the throttle and the operator's use of brakes. In the manual mode, the present invention further considers the operator's selection of a gear condition.

Abstract: A small engine transmission having a hydromechanical transmission unit providing a first power path, and a mechanical power transmission unit providing a second power path. The mechanical power transmission is a planetary gear system having a planetary carrier. The hydromechanical transmission is associated with the mechanical transmission to decrease average hydraulic power flow of the engine transmission to thereby increase operating efficiency and to permit the reduction of an output speed range to reduce transmitted power for the use of multiple modes to achieve a full torque and speed range of the transmission.

Abstract: A priority circuit is provided that is in communication with an open circuit pump and priority and auxiliary systems. The circuit comprises a first valve with an inlet in communication with the pump, an outlet in communication the priority system, and a load sensing inlet in communication with the priority system, wherein the first valve modulates to maintain a predetermined pressure differential between pressure at the load sensing inlet and pressure at the outlet. The circuit further comprises a second valve with an inlet in communication with the pump, an outlet in communication with the auxiliary system, and a load sensing inlet in communication with the priority system, wherein the second valve is normally closed and opens when pressure at the load sensing inlet of the second valve is less than pressure at the inlet of the second valve minus the predetermined pressure differential of the first valve.

Abstract: A current measuring circuit for a PWM driver. The current measuring device measures the high side and low side currents of a PWM driver circuit before the currents reach the driver. A first measuring circuit measures the high side of the circuit and a second measuring circuit measures the low side of the circuit. The second measuring circuit also receives a signal from the first measuring circuit containing the current measurement measured by the first circuit and the second circuit then adds this current to the second circuit current and transmits a signal of the summed currents to a receiving device.

Abstract: The present invention is directed towards a hydraulic power unit including a housing, an internal hydraulic power means, an external hydraulic power means, and a mechanical power shaft associated with the hydraulic power means. In addition, the hydraulic power unit comprises a transducer adapted for measuring torque mounted in the housing in a non-contact relation to the mechanical power shaft adjacent a portion of the shaft imposed with a magnetic field. The hydraulic power unit further comprises a controller associated with the transducer to monitor the measured torque and adjust the operation of the hydraulic power unit accordingly.