Abstract: A hydraulic pump system is provided that includes a pump driven by an electric motor. The electric motor includes windings that receive power from a power source. In one example, a temperature sensor is arranged in proximity to hydraulic fluid associated with the pump, such as at an input of the pump. In another example, the temperature sensor measures the ambient temperature to predict the viscosity of the pump based upon cool down rates of the system. A controller monitors a temperature at the temperature sensor and commands power to be provided to the windings to generate heat. Electric motor power consumption can be monitored to determine viscosity. The heat reduces the viscosity of the hydraulic fluid. Bleed air may be selectively provided to a casing associated with the hydraulic fluid in response to a command from the controller. The controller actuates a valve to regulate the flow of bleed air to the casing to provide supplemental heat to the heat provided by the windings.

Abstract: A hydraulic pump system is provided that includes a pump driven by an electric motor. The electric motor includes windings that receive power from a power source. In one example, a temperature sensor is arranged in proximity to hydraulic fluid associated with the pump, such as at an input of the pump. In another example, the temperature sensor measures the ambient temperature to predict the viscosity of the pump based upon cool down rates of the system. A controller monitors a temperature at the temperature sensor and commands power to be provided to the windings to generate heat. Electric motor power consumption can be monitored to determine viscosity. The heat reduces the viscosity of the hydraulic fluid. Bleed air may be selectively provided to a casing associated with the hydraulic fluid in response to a command from the controller. The controller actuates a valve to regulate the flow of bleed air to the casing to provide supplemental heat to the heat provided by the windings.

Abstract: A continuously variable transmission and method for preventing transmission belt slippage in the case of a sudden increase in load torque on the transmission involves both inserting a lag in the transmission to allow the control loops time to respond to the sudden increase in load torque and speeding up the responses of the control loops in response to the sudden increase in load torque. The transmission is used to drive an aircraft electrical generator at a constant speed in the disclosed embodiment.

Abstract: A continuously variable transmission, and particularly a control arrangement thereof and a method for recovering belt slippage in the transmission, are disclosed. A source of hydraulic pressure is operatively connected for driving each of the hydraulically operated actuators for axially movable sheaves of primary and secondary pulleys of the transmission. A hydraulic pressure control loop controls the hydraulic pressure applied to the actuator of the secondary pulley as a function of the load of the device being driven on the transmission and the pitch radius of the secondary pulley. An output speed control loop controls the output speed of the transmission driving the device to be driven during normal operation of the transmission. Preferably, the output speed control loop may be set to control the output speed at a constant value for driving an aircraft electric generator.

Abstract: An electrical device is capable of sensing both AC and DC current which is flowing through an electrical circuit. The electrical device bifurcates the current into separate paths, wherein impedance of each path has a constant relationship to each other. In a further embodiment, the electrical device includes a current sensor for measuring current flowing through the circuit. The sensor is of a type which does not introduce insertion loss.

Abstract: In order to eliminate leakage and provide a more efficient system, a variable displacement hydraulic apparatus (10) includes a cylinder block (12) having a plurality of hydraulic cylinders (14) therein. Each of the cylinders (14) has a hydraulic piston (16) disposed therein for reciprocating movement relative thereto. The cylinders (14) and pistons (16) are disposed about an axis (18) of the hydraulic apparatus (10). The hydraulic apparatus (10) also includes a shaft (20) operatively associated with the pistons (16) for relative driven movement therebetween and a valve block (22) having a hydraulic fluid inlet port (24) for supplying hydraulic fluid to the cylinders (14) together with a hydraulic fluid outlet port (26) for returning hydraulic fluid from the cylinders (14). The inlet and outlet ports (24 and 26) communicate with the cylinders (14) through a port plate (28) having at least one port slot (30) therethrough.

Abstract: Thrust bearing failure in clutches is avoided in a clutch construction including a housing 10 with first and second coaxial shafts 24, 32 and a clutch pack 34 interconnecting the shafts 24 and 32 for coupling and decoupling the same. A spring 50 is utilized to engage the clutch pack 34 to couple the shafts 24 and 32 while a motor 82, 96 is utilized to decouple the shafts by releasing compression on the clutch pack 34. This is accomplished by moving a thrust bearing 76 to engage a reaction plate 48 forming part of the clutch pack 34 to move the same away from the other reaction plate 34 of the clutch pack to disengage the clutch. The thrust bearing 76 is wholly out of the load path of the clutch when the clutch is engaged.

Abstract: A fault detector for a triplexed mechanical or hydromechanical system which provides for improvement in cost, reliability and weight over previously known balance beam arrangements for achieving redundant two-channel operation to provide a fail-operating first failure mode for operation of aircraft components which require reliable operation for flight safety. The fault detector for a triplexed mechanical or hydromechanical system has a tripodal summing member which receives three mechanical position signals in three different channels with the tripodal summing member retaining a position perpendicular to the force transmitted by the tripodal summing member in response to the position signals and tipping when one of the input signals deviates significantly from the other two.

Abstract: This invention relates to an energy efficient variable displacement motor-driven power drive unit using a multi-variable feedback control system to control system output position and speed. More particularly, a variable displacement hydraulic motor connected to drive a load has a variable-position wobbler, with the position controlled by electro-hydraulic servo means including an electrically-operable servo valve which receives a control signal from signal summing means which has summed feedback signals representing speed and position of a load with a torque signal representative of wobbler position. The latter signal is mechanically inputted to the servo valve by means of a mechanical connection including a link connected to the wobbler and a spring interconnecting the link to the servo valve and with the link carrying a servo piston movable in a servo cylinder associated with the servo valve.