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US 6,672,420 B2Granted
Electronically-controlled coupling for all-wheel drive system
AssigneeNew Venture Gear, Inc.
InventorFred C. Porter
Life of this patent
Estimating the term…
Abstract
A drive axle for an all-wheel drive vehicle includes an adaptively controlled first hydraulic coupling for providing front-to-rear torque transfer control and a passively controlled second hydraulic coupling for providing side-to-side limited slip and torque biasing control. The drive axle is contained with a common housing and communicates with a tractor control system to actively control actuation of the first hydraulic coupling based on the operating characteristics of the vehicle as detected by suitable sensors.
Claims27
A power transfer assembly for transferring drive torque from a vehicular powertrain to a pair of wheels comprising:
- an input member adapted to receive drive torque from the powertrain;
- an output member adapted to transmit drive torque to the wheels;
- a torque coupling for transferring drive torque from said input member to said output member, said torque coupling including a clutch pack operably connected between said input member and said output member, an actuator for applying a clutch engagement force on said clutch pack in response to fluid pressure exerted thereon, and a fluid control system capable of varying the fluid pressure exerted on said actuator, said fluid control system includes a source of hydraulic fluid, and a control valve for controllably regulating the fluid pressure exerted on said actuator;
- a speed sensor for determining a speed difference between said input member and said output member;
- a first temperature sensor for detecting the fluid temperature at said fluid source;
- a second temperature sensor for detecting the fluid temperature at said clutch pack;
- and
- a control unit receiving speed signals from said speed sensor and temperature signals from said first and second temperature sensors and generating an electric control signal in response thereto, said electric control signal is supplied to said control valve for varying the fluid pressure as a function of said electric control signal.
5 more elements
A power transfer assembly for transferring drive torque from a vehicular powertrain to a pair of wheels, comprising:
- an input shaft adapted to receive drive torque from the powertrain;
- a pinion shaft;
- a torque coupling operable for transferring drive torque from said input shaft to said pinion shaft, said torque coupling including a clutch pack interconnected between said input shaft and said pinion shaft, a piston supported in a piston chamber for movement in response to fluid pressure to apply a clutch engagement force to said clutch pack for transferring drive torque to said pinion shaft, a source of hydraulic fluid, a pump having an inlet in communication with said fluid source and an outlet in communication with said piston chamber, and a control valve for regulating the control pressure of hydraulic fluid supplied by said pump to said piston chamber;
- speed sensors for detecting the rotary speeds of said input shaft and said pinion shaft;
- a first temperature sensor for detecting the fluid temperature at said fluid source;
- a second temperature sensor for detecting the fluid temperature at said control valve;
- and
- a controller for receiving sensor signals from said speed sensors and said first and second temperature sensors and generating an electric control signal in response thereto that is sent to said control valve to control movement of said piston.
5 more elements
An all-wheel drive vehicle comprising:
- a powertrain including an engine and a transmission;
- a primary driveline driven by said powertrain for transferring drive torque to a pair of primary wheels;
- a secondary driveline including a drive axle assembly and a pair of secondary wheels, said drive axle assembly having an input member driven by said powertrain, a drive case, a pair of axleshafts connected to said secondary wheels, a differential interconnecting said drive case to said axleshafts so as to permit speed differentiation between said axleshafts, and a torque coupling for transferring drive torque from said input member to said drive case, said torque coupling including a clutch pack operably connected between said input member and said drive case, an actuator for applying a clutch engagement force on said clutch pack in response to fluid pressure exerted thereon, and a fluid control system capable of varying the fluid pressure exerted on said actuator, said fluid control system includes a source of hydraulic fluid, and an electric control valve for controllably regulating the control pressure exerted on said actuator;
- speed sensors for determining a speed difference between said input member and at lease one of said drive case and said axleshafts;
- a first temperature sensor for detecting the fluid temperature at said fluid source;
- a second temperature sensor for detecting the fluid temperature at said clutch pack;
- and
- a traction control unit receiving speed signals from said speed sensors and temperature signals from said first and second temperature sensors and generating an electric control signal in response thereto, said electric control signal is supplied to said electric control valve for varying the control pressure as a function of said electric control signal.
5 more elements
An all-wheel drive vehicle comprising:
- a powertrain including an engine and a transmission;
- a primary driveline driven by said powertrain for transferring drive torque to a pair of primary wheels;
- a power take-off unit driven by said primary driveline;
- a secondary driveline including a drive axle assembly and a pair of secondary wheels, said drive axle assembly having an input shaft driven by said power take-off unit, a pinion shaft, and a torque coupling operable for transferring drive torque from said input shaft to said pinion shaft, said torque coupling including a clutch pack interconnected between said input shaft and said pinion shaft, a piston supported in a piston chamber for movement in response to fluid pressure to apply a clutch engagement force to said clutch pack for transferring drive torque to said pinion shaft, a pump having an inlet in communication with a sump and an outlet in communication with said piston chamber, and a control valve for regulating the control pressure of hydraulic fluid supplied to said piston chamber;
- speed sensors for detecting the rotary speeds of said input shaft and said pinion shaft;
- a first temperature sensor for detecting the temperature of fluid in said sump,
- a second temperature sensor for detecting the fluid temperature at said control valve;
- and
- a controller for receiving sensor signals from said speed sensors and said first and second temperature sensors and generating an electric control signal in response thereto that is sent to said electric control valve to control movement of said piston.
6 more elements
Dependencies are inferred from the claim text.