Abstract: Positive displacement machines and methods therefor capable of increasing a load-carrying capacity of a piston-cylinder lubrication interface of positive displacement machines having a cylinder block, a cylindrical bore defined in the cylinder block, a piston reciprocably disposed within the cylindrical bore, and a working fluid within the piston-cylinder lubrication interface to provide a load-bearing function between the piston and the bore wall of the cylinder bore. The method includes providing at least one circumferential groove on a bore wall of the cylindrical bore within the piston-cylinder lubrication interface having an opening facing the piston and that is in fluidic communication with the piston-cylinder lubrication interface so as to contain a portion of the working fluid, and operating the positive displacement machine such that the working fluid enters the cylindrical groove and promotes hydrostatic balancing of pressure of the working fluid within the piston-cylinder lubrication interface.

Abstract: Positive displacement machines and methods therefor capable of increasing a load-carrying capacity of a piston-cylinder lubrication interface of positive displacement machines having a cylinder block, a cylindrical bore defined in the cylinder block, a piston reciprocably disposed within the cylindrical bore, and a working fluid within the piston-cylinder lubrication interface to provide a load-bearing function between the piston and the bore wall of the cylinder bore. The method includes providing at least one circumferential groove on a bore wall of the cylindrical bore within the piston-cylinder lubrication interface having an opening facing the piston and that is in fluidic communication with the piston-cylinder lubrication interface so as to contain a portion of the working fluid, and operating the positive displacement machine such that the working fluid enters the cylindrical groove and promotes hydrostatic balancing of pressure of the working fluid within the piston-cylinder lubrication interface.

Abstract: A machine and method for a hydrostatic axial sliding bearing that has bearing and sealing functions and is capable of exhibiting reduced power losses. The hydrostatic axial sliding bearing of the machine is defined by axial sliding bearing surfaces that are separated by a fluid film and adapted for movement relative to each other during operation of the machine. The machine has first and second elements that define a first and a second of the axial sliding bearing surfaces. In combination, the first and second axial sliding bearing surfaces function as bearing and sealing surfaces for the hydrostatic axial sliding bearing. The machine is adapted so that the first and second axial sliding bearing surfaces move relative to each other in a first direction of motion, and at least the second axial sliding bearing surface has a surface profile with an oscillatory waveform in the first direction of motion.

Abstract: A system and method for performing a floating function in an earthmoving implement of an earthmoving machine without physically connecting chambers within a hydraulic actuator that is adapted to raise and lower the earthmoving implement. The system includes a device for delivering a pressurized fluid to and receiving pressurized fluid from the actuator, a valve for compensating for differences in volume between chambers of the actuator, and an electronic control circuit that includes electronic sensors for sensing the pressures in the chambers of the actuator, and a controller for receiving outputs of the sensors. The controller calculates an amount of the pressurized fluid that, when delivered to or received from the actuator, achieves a substantially constant pressures in the chambers of the actuator and enables the earthmoving implement to float regardless of motion of the actuator.

Abstract: A system and method for controlling the movement of an implement of an earthmoving machine. The system includes a hydraulic actuator adapted to move the implement. A variable displacement pump is coupled to the actuator for delivering a pressurized fluid to and receiving pressurized fluid from chambers within the actuator. A sensor generates an output based on the position of the actuator's piston or piston rod, and a controller controls the displacement of the variable displacement pump in response to the output of the sensor by executing an algorithm to reduce the flow rate of the fluid to and from the actuator's chambers and thereby reduce the velocity of the piston as it approaches an end of a piston stroke thereof and prevent the piston from impacting the actuator at the end of the piston stroke.

Abstract: Power split drive (PSD) transmissions capable of energy recovery and suitable for use in automotive applications. Each PSD transmission includes a mechanical transmission system for mechanically transmitting mechanical power between a rotatable input shaft and a rotatable output shaft, and a hydraulic transmission system containing a fluid for hydraulically transmitting hydraulic power between the input shaft and the output shaft, and at least a third shaft operatively interconnected to one of the mechanical and hydraulic transmission systems. The hydraulic transmission system is operatively coupled by at least a first planetary gear train to the mechanical transmission system. According to the invention, the PSD further comprises means operatively associated with at least one of the mechanical and hydraulic transmission systems for storing and releasing energy within the PSD transmission, the energy storing and releasing means comprising a flywheel or an accumulator or a combination thereof.

Abstract: Power split drive (PSD) transmissions capable of energy recovery and suitable for use in automotive applications. Each PSD transmission includes a mechanical transmission system for mechanically transmitting mechanical power between a rotatable input shaft and a rotatable output shaft, and a hydraulic transmission system containing a fluid for hydraulically transmitting hydraulic power between the input shaft and the output shaft, and at least a third shaft operatively interconnected to one of the mechanical and hydraulic transmission systems. The hydraulic transmission system is operatively coupled by at least a first planetary gear train to the mechanical transmission system. According to the invention, the PSD further comprises means operatively associated with at least one of the mechanical and hydraulic transmission systems for storing and releasing energy within the PSD transmission, the energy storing and releasing means comprising a flywheel or an accumulator or a combination thereof.

Abstract: Systems and methods for controlling and actuating actuators that perform multiple functions in a machine. Such systems and methods encompass a hydraulic system adapted to control and actuate the actuators of the machine. The hydraulic system includes variable displacement pump/motors connected to the engine in parallel. A first of the pump/motors controls a first of the actuators, and a second of the pump/motors is adapted to draw power from and deliver power to the engine and the first actuator, as well as control at least a second of the actuators. An energy storage device is connected in series with the second pump/motor and the second actuator, and accumulates a fluid pumped thereto by the second pump/motor, as well as delivers the fluid to the second pump/motor, depending on whether the second pump/motor delivers is delivering or drawing power from the engine or first actuators.

Abstract: A displacement-controlled hydraulic system for installation on a multi-function machine, and multi-function machines equipped with the hydraulic system and having devices for propelling the machine, at least a first implement, and multiple actuators that perform multiple functions of the machine. The multiple actuators include first actuators that control the first implement and second actuators that control the propelling devices. The hydraulic system comprises multiple pumps for controlling the first actuators and optionally the second actuators, and valves that enable at least one of the pumps to sequentially control two of the multiple actuators and a corresponding two functions of the multiple functions performed thereby. None of the pumps sequentially controls the second actuators in combination with any of the first actuators.

Abstract: A piston and cylinder assembly suitable for use in positive displacement machines (10) and capable of minimizing power losses resulting from friction and fluid leakage over a range of operating parameters. The piston (14) is reciprocably disposed within a cylinder (16) having a uniform diameter. The piston (14) has a bearing surface (30) that defines a diametrical clearance with the cylindrical bearing surface of the cylinder (16) of up to about two percent of the cylinder diameter. The diametrical clearance defines a lubrication gap (26) and a hydrodynamic seal between the piston (14) and the cylinder (16). The piston (14) further has alternating crests (34) and valleys (36) defined in a nominally cylindrical shape (28) of its bearing surface (30). The crests (34) and valleys (36) are oriented and spaced on the bearing surface (30) to define a wavy surface form (32) along the entire axial length of the bearing surface (30).

Abstract: A system for automatically controlling the position and level of an earthmoving implement on an earthmoving machine. The system includes at least one hydraulic actuator adapted to raise and lower the earthmoving implement, a device for delivering a pressurized fluid to and receiving pressurized fluid from the actuator, and an electronic control circuit that includes electronic sensors for sensing the absolute orientation of the machine and the position of the actuator, and a controller for receiving outputs of the sensors, calculating an amount of the pressurized fluid that must be delivered to or received from the actuator to achieve a desired position for the earthmoving implement, and control the delivering-receiving device to deliver or receive the amount of the pressurized fluid to achieve the desired position for the earthmoving implement.

Abstract: A machine and method for a hydrostatic axial sliding bearing that has bearing and sealing functions and is capable of exhibiting reduced power losses. The hydrostatic axial sliding bearing of the machine is defined by axial sliding bearing surfaces that are separated by a fluid film and adapted for movement relative to each other during operation of the machine. The machine has first and second elements that define a first and a second of the axial sliding bearing surfaces. In combination, the first and second axial sliding bearing surfaces function as bearing and sealing surfaces for the hydrostatic axial sliding bearing. The machine is adapted so that the first and second axial sliding bearing surfaces move relative to each other in a first direction of motion, and at least the second axial sliding bearing surface has a surface profile with an oscillatory waveform in the first direction of motion.

Abstract: A system for automatically controlling the position and level of an earthmoving implement on an earthmoving machine. The system includes at least one hydraulic actuator adapted to raise and lower the earthmoving implement, a device for delivering a pressurized fluid to and receiving pressurized fluid from the actuator, and an electronic control circuit that includes electronic sensors for sensing the absolute orientation of the machine and the position of the actuator, and a controller for receiving outputs of the sensors, calculating an amount of the pressurized fluid that must be delivered to or received from the actuator to achieve a desired position for the earthmoving implement, and control the delivering-receiving device to deliver or receive the amount of the pressurized fluid to achieve the desired position for the earthmoving implement.

Abstract: A system and method for performing a floating function in an earthmoving implement of an earthmoving machine without physically connecting chambers within a hydraulic actuator that is adapted to raise and lower the earthmoving implement. The system includes a device for delivering a pressurized fluid to and receiving pressurized fluid from the actuator, a valve for compensating for differences in volume between chambers of the actuator, and an electronic control circuit that includes electronic sensors for sensing the pressures in the chambers of the actuator, and a controller for receiving outputs of the sensors. The controller calculates an amount of the pressurized fluid that, when delivered to or received from the actuator, achieves a substantially constant pressures in the chambers of the actuator and enables the earthmoving implement to float regardless of motion of the actuator.

Abstract: A displacement-controlled hydraulic system for installation on a multi-function machine, and multi-function machines equipped with the hydraulic system and having devices for propelling the machine, at least a first implement, and multiple actuators that perform multiple functions of the machine. The multiple actuators include first actuators that control the first implement and second actuators that control the propelling devices. The hydraulic system comprises multiple pumps for controlling the first actuators and optionally the second actuators, and valves that enable at least one of the pumps to sequentially control two of the multiple actuators and a corresponding two functions of the multiple functions performed thereby. None of the pumps sequentially controls the second actuators in combination with any of the first actuators.

Abstract: A system and method for controlling the movement of an implement of an earthmoving machine. The system includes a hydraulic actuator adapted to move the implement. A variable displacement pump is coupled to the actuator for delivering a pressurized fluid to and receiving pressurized fluid from chambers within the actuator. A sensor generates an output based on the position of the actuator's piston or piston rod, and a controller controls the displacement of the variable displacement pump in response to the output of the sensor by executing an algorithm to reduce the flow rate of the fluid to and from the actuator's chambers and thereby reduce the velocity of the piston as it approaches an end of a piston stroke thereof and prevent the piston from impacting the actuator at the end of the piston stroke.