Auburn Gear, Inc.

Dana Corporation

Robert Leeper

James L Forrest

David C Reuter

Ralph W Baxter, Jr

James P Scott

Thomas N Till

John S Sewell

A differential assembly including a rotatable casing having an axis of rotation, a selectively energized electromagnet proximal the casing, and a rotatable first clutch disposed within the casing, the first clutch placed in operative engagement with the casing in response to the electromagnet being energized. Relative rotation between the first clutch and the casing is slowed by their being in operative engagement. A rotatable clutch hub and a second clutch are disposed within the casing, and the casing and the clutch hub are rotatably coupled through engagement of the second clutch, which is operatively engaged in response to relative rotation between the first clutch and the casing being slowed. At least one rotatable pinion gear is disposed within the casing and revolves about the axis of rotation. At least one side gear engaged with the pinion gear and rotatable about the axis of rotation is disposed within the casing, and is rotatably coupled to the casing through the second clutch during engagement of the second clutch. Neither of the first clutch and the second clutch is appreciably engaged with the casing in response to gear separating forces exerted between the pinion gear and the side gear.

Electromagnetically locking differential

A differential assembly including a rotatable casing, first and second axially moveable side gears disposed within the casing, at least one pinion gear disposed within the casing and intermeshed with the side gears, a cone clutch operatively coupled to the first side gear, the cone clutch being frictionally coupled to the casing in response to being exposed to a magnetic field, and a disc clutch having at least one clutch disc operatively coupled to the second side gear in response to axial movement of the second side gear.

Electromagnetically-actuated limited slip differential

A limited slip differential including a rotatable casing, a pair of axle shafts including respective ends, a pair of side gears rotatably fixed to the ends of the axle shafts, at least one pinion gear attached to the casing and meshingly engaged with the pair of side gears, a brake assembly defining a brake chamber and including first and second brake elements disposed within the brake chamber, the first brake element superposed with the second brake element, the first brake element rotatably fixed relative to the casing, a quantity of magnetorheological fluid disposed within the brake chamber, the first and second brake elements in contact with the magnetorheological fluid, and a selectively energized source of magnetic flux, the magnetorheological fluid being exposed to the flux when the source is energized. When the magnetorheological fluid is exposed to the magnetic flux, the magnetorheological fluid is at least partially solidified and the first and second brake elements are coupled to each other through the magnetorheological fluid.

Limited slip differential having magnetorheological fluid brake

An electrically actuated limited slip axle assembly for transferring torque including a housing, a clutch, a casing and an electromagnet fixedly mounted to the housing. The casing is rotatably supported on bearings within the housing. The clutch is activated in response to energization of the electromagnet to transfer torque. In a first embodiment the electromagnet is coupled to a cup portion of the bearing, whereby the electromagnet is fixedly mounted to the housing via the bearing. In a second embodiment of the axle assembly includes a bearing spacer providing the fixed mount between the housing and the electromagnet.

Direct housing mount of electromagnet

A limited slip differential having at least one cone clutch element for frictionally engaging an interior surface of the rotatable differential casing. The cone clutch element has a plurality of clutch engagement surfaces which are disposed about the outside surface of the cone clutch element. Recessed areas are interposed between the clutch engagement surfaces. The total clutch engagement surface area is reduced to between 5% and 15% of the total engagement and recessed surface area of the clutch element to improve the performance of the differential at lower temperatures.

Cone clutch structure having recessed areas for use in a limited slip differential

An apparatus and method for demagnetizing a differential which has a controllable electromagnetically actuated clutch. The apparatus includes sensors and a coil connected to a control module. The sensors receive vehicle inputs to indicate various measured values such as vehicle speed, brake pressure, magnetization current provided to the differential, and the like and generates signals which are transmitted to the control module. The control module initiates a demagnetization cycle when certain conditions have been satisfied as indicated by the input signals. The control module provides a DC voltage to the coil to generate magnetic flux for demagnetizing the differential and the components of the differential. In one embodiment a single coil is provided to which is applied both magnetization and demagnetization current. In another embodiment two coils are provided, one for generating magnetization flux and the other for generating demagnetization flux. The control alternatively applies voltages of reverse polarity in decreasing amplitudes for predetermined periods of time during a demagnetization cycle.

Apparatus and method for demagnetizing a controllable

A limited slip differential having at least one cone clutch element for frictionally engaging an interior surface of the rotatable differential casing. The cone clutch element has a plurality of clutch engagement surfaces which are disposed about the outside surface of the cone clutch element. Recessed areas are interposed between the clutch engagement surfaces.

Conical clutch member having recessed areas for use in a limited slip

A controllable differential having a rotatable casing, differential gearing disposed within the rotatable casing and linking the casing with an output element disposed therein, a clutch disposed within the rotatable casing and clutch adapted to transfer torque between the rotatable casing and the output element, and an electromagnet arranged to generate a generally toroidal magnetic flux path encircling the electromagnet and magnetically forcing the clutch into engagement with the rotatable casing, the casing including a nonmagnetic portion adjacent the electromagnet, said flux path surrounding the nonmagnetic casing portion.

Electronically controllable limited slip differential having nonmagnetic

A four-wheel drive transfer case including a force sensor and associated electronics for sensing the reaction forces on driven members within the transfer case, such as in association with an output shaft and its bearings. The force sensor and associated control system establish an output signal which varies depending upon the magnitude of the reaction force and yields an indication of the torque distribution between the output shafts of the transfer case. The output voltage signal is used by a torque monitoring and control system to vary and/or limit the magnitude of torque transmitted to the output shaft.

Four-wheel drive transfer case with torque sensing

A controllable differential having a clutch mechanism which transfers a predetermined amount of torque between a rotatable differential casing and a side gear when an initiating force is applied by an electronic actuator. A pair of sensors provide inputs to the electronic actuator which, in turn, actuates an electromagnet. A clutch mechanism is actuated by the electromagnet and applies an initiating force to the clutch mechanism to initially actuate the clutch mechanism when a predetermined relative rotational condition of the side gears is sensed. The application of the initiating force in combination with the interaction between engagement surfaces and between camming portions fully engages a clutch mechanism to transfer a predetermined controllable amount of torque.

Electronically controllable limited slip differential

A speed sensitive limited slip differential having a sealed, self contained clutch actuator which expands and retracts as required to frictionally seat a clutch element against a surface of the differential casing. The clutch actuator comprises a housing portion and a piston portion which define two fluid chambers and a gerotor pump assembly contained therein for transferring fluid between the two fluid chambers. The gerotor pump assembly is splined to an output element to transfer fluid between the two chambers when sufficient differential rotation between the output element and the casing exists. The transfer of fluid between the two chambers results in the axial expansion of the actuator housing and the actuator piston to provide an axial force on a side gear to thereby frictionally seat the clutch element against a surface of the differential casing. The sealed, self contained feature allows the present limited slip differential to operate in a simple, reliable manner.

Speed sensitive limited slip differential

The present invention relates to a vehicle four wheel drive torque transfer case having a friction clutch which is selectively engaged when it is desired to place the transfer case in a four wheel drive operating mode. The transfer case includes an input shaft which is connected to supply torque to a rear output shaft. A multi-disc friction clutch is connected between the input shaft and a front output shaft for supplying torque to the front output shaft. A planetary gear assembly includes a sun gear, a carrier a planet carrier connected to the input shaft, and a ring gear coupled to drive the front output shaft. The multi-disc clutch is interposed between the sun gear and the ring gear and is engaged to inhibit any rotation of the planet carrier relative to the ring gear and thereby transfer torque to the front output shaft. The planetary gear assembly functions as a .sctn.'torque multipler' and this reduces the torque capacity requirements for the clutch.

Vehicle torque transfer case

The present invention is directed to an electronic actuator for use in a vehicle transmission such as a four wheel drive transfer case. In one preferred embodiment, the transfer case includes two separate electronic actuators, a range shift actuator which is utilized to effect shifting of the transfer case between high range, neutral, and low range drive positions, and a clutch actuator which is utilized to control engagement of a clutch between two wheel drive, automatic ('on demand' four wheel drive), and 'part time' four wheel drive operating modes. The range shift actuator includes a rotary electric motor coaxially mounted relative to a rear output shaft of the transfer case, and a linear screw for translating the rotational movement of the motor shaft to selective axial movement of a range shift sleeve. The clutch actuator is similar to the range shift actuator except that, since the torque requirements necessary to bias the clutch are substantially greater than that necessary to effect the range shift, the clutch actuator includes additional gear reduction to enable the actuator to generate a sufficient axial force to fully engage the clutch. The actuators do not draw any current load after they have moved to their controlled positions and, because the linear screws can not be back driven, their previously set positions are maintained in the event of motor failure or power loss.

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Fort Wayne, IN, United States of America

Robert Leeper