Abstract: A system of a work vehicle includes an engine, a transmission that includes a hydrostatic unit, and a clutch coupled to the transmission. The system also includes a controller communicatively coupled to the engine, the transmission, and the clutch. The controller, in operation, receives a command to disengage the clutch. The controller, in operation, determines an engine speed of the engine. The controller, in operation, also determines a temperature of hydraulic fluid in the clutch. The controller, in operation, further determines a magnitude and time to limit acceleration of the work vehicle based on the engine speed and the temperature. The controller, in operation, also commands the clutch to disengage. The controller, in operation, further limits the acceleration of the work vehicle using the hydrostatic unit based on the magnitude for the time determined.

Abstract: A system for operating a work vehicle may include an engine and a transmission coupled to the engine. The transmission may include a planetary gear unit configured to be selectively coupled to the engine by engaging one of two directional clutches of the transmission. The transmission may also include a hydrostatic drive unit having an input configured to be rotationally coupled to the engine and an output configured to be rotationally coupled to the planetary gear unit. Moreover, the transmission may include a bypass shaft assembly having a bypass shaft configured to be selectively coupled between the output of the hydrostatic drive unit and a given range clutch of the transmission via a bypass clutch. In addition, the system may include a controller configured to operate the transmission in a hydrostatic bypass mode by disengaging the directional clutches and by engaging the bypass clutch and the given range clutch.

Abstract: A system of a work vehicle includes an engine, a transmission that includes a hydrostatic unit, and a clutch coupled to the transmission. The system also includes a controller communicatively coupled to the engine, the transmission, and the clutch. The controller, in operation, receives a command to disengage the clutch. The controller, in operation, determines an engine speed of the engine. The controller, in operation, also determines a temperature of hydraulic fluid in the clutch. The controller, in operation, further determines a magnitude and time to limit acceleration of the work vehicle based on the engine speed and the temperature. The controller, in operation, also commands the clutch to disengage. The controller, in operation, further limits the acceleration of the work vehicle using the hydrostatic unit based on the magnitude for the time determined.

Abstract: A method of calibrating a hydraulically operated clutch in a continuously variable transmission of a vehicle, includes steps of filling the clutch as if for a shift, using a control signal value for achieving a test pressure, and determining a resulting change in a pressure condition in a hydrostatic power unit of the transmission. If the change indicates initial engagement, then a value representative of the signal value used is recorded. If greater than initial engagement is indicated, or the vehicle moved, then the clutch is emptied and tested using a lower test pressure. If initial engagement is not indicated, the clutch is emptied and refilled to a greater test pressure. An exemplary pressure condition is a difference in pressure in lines between a pump and motor of the power unit. During the calibration, the vehicle can be held stationary with a parking brake or the like.

Abstract: A swash plate angle for a hydrostatic power unit of a continuously variable hydromechanical transmission is determined using a feedforward compensation term, to reduce reliance on closed loop control. The feedforward term is based on knowledge of the hydrostatic power unit determined as a function of knowledge of certain parameters, including, but not limited to, hydrostatic power unit pressure, swash plate angle, desired hydrostatic power unit ratio, and pump speed.

Abstract: A method of calibrating a hydraulically operated park brake of a continuously variable transmission of a vehicle. With the vehicle moving at a set, slow speed within a specified range, and the park brake off, a search technique is used, wherein the brake hydraulic pressure is reduced by application of a control signal of a selected test value to apply the brake. When the selected test value is reached, it is held constant, and a condition in a HSU of the transmission is monitored for a change indicative of engagement of the park brake. This will expectedly be in the form of a pressure change and more particularly an increase indicating initial contact between the plates of the brake, and if the HSU change is not detected, the step will time out and another control signal value will be tested.

Abstract: The method of estimating and controlling driveline torque in a continuously variable hydro-mechanical transmission uses pressure data and other metrics of a hydrostatic power unit of the transmission in lieu of actual driveline torque data. A mechanical efficiency of the transmission is determined as a function of whether the power unit is operating in a power generation or regeneration mode, and the torque output of the power unit is estimated from that and other hydrostatic parameters. This is used to estimate a torque output of a planetary power unit of the transmission, and the torque on an output member of the driveline is then estimated using that value, and appropriate corrective action taken.

Abstract: A shuttle shifting method for a continuously variable transmission automatically selects a manner of shuttle shifting as a function of certain monitored conditions. As one alternative, the direction of operation of the transmission is changed prior to reducing the vehicle speed to zero, and tilt of a swash plate of the hydrostatic power unit of the transmission is held substantially constant, for achieving fast, smooth shifts at faster starting and ending vehicle speeds, without coming to a complete stop. In another alternative, for slower starting and ending speeds, or other conditions such as a temperature condition is present, the vehicle is stopped by changing swash plate angle before effecting a directional change of the transmission and the swash plate.

Abstract: A parking brake is controlled in concert with operation of a hydrostatic power unit of a continuously variable transmission, particularly when engaging, disengaging and shuttle shifting the transmission, to provide advantages, particularly when on hills. When particular commands are received, such as shifting to a non-moving position, the parking brake is automatically engaged to hold the vehicle position. A swash plate of the hydrostatic unit can be automatically positioned to anticipate the next command. If that command is received, the brake is automatically gradually or proportionally released and the transmission engaged to effect the commanded movement of the vehicle. If a different command is received, the brake remains engaged as the transmission is configured for the commanded movement, such that no machine movement results. Then the brake is automatically gradually or proportionally released and the transmission engaged to effect that commanded movement.

Abstract: A method of calibrating a hydraulically operated clutch in a continuously variable transmission of a vehicle, includes steps of filling the clutch as if for a shift, using a control signal value for achieving a test pressure, and determining a resulting change in a pressure condition in a hydrostatic power unit of the transmission. If the change indicates initial engagement, then a value representative of the signal value used is recorded. If greater than initial engagement is indicated, or the vehicle moved, then the clutch is emptied and tested using a lower test pressure. If initial engagement is not indicated, the clutch is emptied and refilled to a greater test pressure. An exemplary pressure condition is a difference in pressure in lines between a pump and motor of the power unit. During the calibration, the vehicle can be held stationary with a parking brake or the like.

Abstract: A shuttle shifting method for a continuously variable transmission automatically selects a manner of shuttle shifting as a function of certain monitored conditions. As one alternative, the direction of operation of the transmission is changed prior to reducing the vehicle speed to zero, and tilt of a swash plate of the hydrostatic power unit of the transmission is held substantially constant, for achieving fast, smooth shifts at faster starting and ending vehicle speeds, without coming to a complete stop. In another alternative, for slower starting and ending speeds, or other conditions such as a temperature condition is present, the vehicle is stopped by changing swash plate angle before effecting a directional change of the transmission and the swash plate.

Abstract: A method of calibrating a hydraulically operated park brake of a continuously variable transmission of a vehicle. With the vehicle moving at a set, slow speed within a specified range, and the park brake off, a search technique is used, wherein the brake hydraulic pressure is reduced by application of a control signal of a selected test value to apply the brake. When the selected test value is reached, it is held constant, and a condition in a HSU of the transmission is monitored for a change indicative of engagement of the park brake. This will expectedly be in the form of a pressure change and more particularly an increase indicating initial contact between the plates of the brake, and if the HSU change is not detected, the step will time out and another control signal value will be tested.

Abstract: A swash plate angle for a hydrostatic power unit of a continuously variable hydromechanical transmission is determined using a feedforward compensation term, to reduce reliance on closed loop control. The feedforward term is based on knowledge of the hydrostatic power unit determined as a function of knowledge of certain parameters, including, but not limited to, hydrostatic power unit pressure, swash plate angle, desired hydrostatic power unit ratio, and pump speed.

Abstract: A parking brake is controlled in concert with operation of a hydrostatic power unit of a continuously variable transmission, particularly when engaging, disengaging and shuttle shifting the transmission, to provide advantages, particularly when on hills. When particular commands are received, such as shifting to a non-moving position, the parking brake is automatically engaged to hold the vehicle position. A swash plate of the hydrostatic unit can be automatically positioned to anticipate the next command. If that command is received, the brake is automatically gradually or proportionally released and the transmission engaged to effect the commanded movement of the vehicle. If a different command is received, the brake remains engaged as the transmission is configured for the commanded movement, such that no machine movement results. Then the brake is automatically gradually or proportionally released and the transmission engaged to effect that commanded movement.

Abstract: The method of estimating and controlling driveline torque in a continuously variable hydro-mechanical transmission uses pressure data and other metrics of a hydrostatic power unit of the transmission in lieu of actual driveline torque data. A mechanical efficiency of the transmission is determined as a function of whether the power unit is operating in a power generation or regeneration mode, and the torque output of the power unit is estimated from that and other hydrostatic parameters. This is used to estimate a torque output of a planetary power unit of the transmission, and the torque on an output member of the driveline is then estimated using that value, and appropriate corrective action taken.

Abstract: A suspension system for a rigid beam tractor axle in which the axle is connected to the chassis by two orthogonally oriented pivot points and axle movement is controlled by hydraulic cylinders to improve the ride and handling characteristics of the tractor.

Abstract: A suspension system for a rigid beam tractor axle in which the axle is connected to the chassis by two orthogonally oriented pivot points and axle movement is controlled by hydraulic cylinders to improve the ride and handling characteristics of the tractor.

Abstract: A mechanical drive clutch is provided for mounting on a rotatable shaft. The drive clutch includes a drive gear having a plurality of gear teeth projecting therefrom. A sleeve is slidably mounted on the shaft for rotational movement therewith. The sleeve includes a plurality of gear engagement recesses therein of arcuate lengths greater than the predetermined arcuate lengths of the gear teeth. The sleeve is moveable between a first retracted position and a second engaged position wherein the gear teeth are received within corresponding gear engagement recesses in the sleeve in order to translate rotation of the drive gear to the shaft. A plurality of anti-backlash elements are provided to compensate for the difference in the arcuate lengths of gear teeth and their corresponding gear engagement recesses in the sleeve.