Abstract: A multistage wheel drive includes primary and secondary planetary stages, in which the ring gear of the primary (i.e., input-side) planetary stage is formed from a single machined part which also includes the planet gear carrier of the secondary (i.e., output-side) planetary stage. This dual-function “combination” component includes a splined exterior surface which interfaces with a correspondingly splined interior surface on the spindle in order to rotationally fix the combination component to the spindle. This arrangement ensures concentricity between the primary and secondary planetary stages, while allowing a desired amount of radial tolerance between the spindle, the combination component, and the hub of the wheel drive. In addition, the present arrangement can be produced efficiently and inexpensively.

Abstract: Structural arrangements of wheel drive components facilitate the use of robust main roller bearings that are widely spaced apart from one another. This wide spacing minimizes the torque borne by the bearings for a given external load, because at least one bearing is placed closer to the expected load application point (e.g., the center of gravity of the wheel attached to the wheel hub of the drive unit). The present wheel drive bearings can support a heavy external load without expanding the overall size and configuration of a given wheel drive application.

Abstract: A multispeed drive unit (10) comprising a rotary input (27) positioned to be driven by a power source and disposed at an input side of the drive unit (10); a rotary output (28) positioned to drive a driven unit and disposed at an output side of the drive unit (10), a transmission operably interposed between said rotary input (27) and said rotary output (28), said transmission having a gear (20) moveable between a high-reduction configuration and a low-reduction configuration, a first friction clutch (40) operable to fix said gear (20) in said high-reduction configuration, whereby said transmission is operable to reduce a speed of said rotary output (28) relative to said rotary input (27) when said first friction clutch (40) is engaged, and a second friction clutch (60) operable to fix said gear (20) in said low-reduction configuration, whereby said transmission is not operable to reduce the speed of said rotary output (28) relative to said rotary input (2) when said second friction clutch (60) is engaged.

Abstract: A selectively locked differential has a locked configuration in which both side gears are independently locked to the differential casing so that torque is not transmitted through the pinion gears. The locking of the side gears is accomplished by generally cylindrical, ring-shaped structures with castellations on one axial end surface of each structure. These castellations selectively interfit with rotatably fixed castellations of secondary structures fixed to the differential casing, such that the ring-shaped structures define a mechanically interconnected, zero-slip arrangement with respect to the rotationally fixed secondary structures when the differential is in the locked configuration.

Abstract: A drive unit disconnect mechanism is operable to transmit or disconnect power from a vehicle power source to a driven unit, and can be disengaged by multiple methods depending on how much force is required to separate the internal components of the mechanism. In a first, relatively quicker method, a handle is pulled axially away from the hub to withdraw and internal gear from splined engagement with a corresponding driven gear. In a second, relatively slower method, the handle is rotated to threadably withdraw the entire disconnect mechanism from the hub, which in turn withdraws the internal gear from splined engagement with the driven gear. The quicker method is desirable in most instances, but the slower method allows disconnection of the driven unit from the vehicle power source when gear pressure prevents or impedes the quicker method.

Abstract: A selectively locked differential has a locked configuration in which both side gears are independently locked to the differential casing so that torque is not transmitted through the pinion gears. The locking of the side gears is accomplished by generally cylindrical, ring-shaped structures with castellations on one axial end surface of each structure. These castellations selectively interfit with rotatably fixed castellations of secondary structures fixed to the differential casing, such that the ring-shaped structures define a mechanically interconnected, zero-slip arrangement with respect to the rotationally fixed secondary structures when the differential is in the locked configuration.

Abstract: A disconnect shaft arrangement interposes a biasing element between a shoulder formed on the disconnect shaft and a cup-shaped washer, in which the cup-shaped washer is sized and configured to be axially displaceable with respect to the disconnect shaft. The cup-shaped washer selectively engages an axially fixed adjacent structure, such as a thrust washer, during disengagement of the disconnect shaft and attendant spring compression. The present disconnect shaft arrangement obviates the need for a retaining ring against which the spring compresses, such that the relatively deep retaining ring groove needed for such a retaining ring need not be cut into the outer surface of the disconnect shaft. Removal of material in the outer surface of the shaft is therefore minimized, such that the torque transmission capability of the shaft is maximized.

Abstract: A drive unit disconnect mechanism is operable to transmit or disconnect power from a vehicle power source to a driven unit, and can be disengaged by multiple methods depending on how much force is required to separate the internal components of the mechanism. In a first, relatively quicker method, a handle is pulled axially away from the hub to withdraw and internal gear from splined engagement with a corresponding driven gear. In a second, relatively slower method, the handle is rotated to threadably withdraw the entire disconnect mechanism from the hub, which in turn withdraws the internal gear from splined engagement with the driven gear. The quicker method is desirable in most instances, but the slower method allows disconnection of the driven unit from the vehicle power source when gear pressure prevents or impedes the quicker method.

Abstract: 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.

Abstract: An integrated drive unit having planetary gearing and an annular cone brake element affixed to a hydraulic motor barrel. A brake piston encircles the hydraulic motor barrel and is selectively engageable with the cone brake element to actuate the cone brake element into frictional contact with the spindle of the integrated drive unit to act as a safety/parking brake. The cone brake element is formed of a bronze-type powdered metal of sufficient durability to withstand dynamic braking. The hydraulic motor is selectively connectable to a transmission including planetary gearing. The planetary gearing of the present invention includes a planet gear carrier having carrier pins formed of a relatively low carbon steel and locally hardened over the area on which the planet gears will be supported. In an alternative embodiment, a carrier pins sleeve formed of VESPEL is utilized as the bearing between the planet gear and the carrier pin.

Abstract: A disconnect mechanism for a drive unit (e.g., a wheel drive unit or an integrated drive unit) including a wheel carrying hub rotatably attached to a frame and a reciprocal input shaft operable to selectively connect a power source (e.g., a hydraulic motor) to a transmission connected to the hub. The disconnect mechanism is connected to the input shaft and is adapted to be selectively hand actuated. The disconnect mechanism includes a hand rotatable knob rotatably connected to a cover removably attached to and enclosing an end of the hub. The knob includes an annular helical surface (i.e., ramp surface) operable to axially displace the input shaft from a first position in which the input shaft is drivingly connected to the transmission and, thus, the hub to a second position in which the input shaft is disconnected from the transmission. A disconnect pin is positioned intermediate the disconnect knob and the input shaft and rides on the ramp surface of the disconnect knob.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A differential assembly including a casing which rotates about a first axis, the casing having an internal cavity; an elongate cylindrical cross pin which rotates with the casing about the first axis, the cross pin extending along a second axis through the cavity, the second axis substantially perpendicular to the first axis; at least one pinion gear disposed within the cavity and about the cross pin, the pinion gear rotatable about the second axis; and a pair of side gears disposed within the cavity and in meshed engagement with the pinion gear, the side gears rotatable about the first axis. A cross pin retention element is disposed about the cross pin. The cross pin and the retention element are fixed against substantial relative movement therebetween along the second axis, and the retention element is disposed adjacent the pinion gear. The movement of the retention element relative to the casing along the second axis is restricted, whereby the cross pin is retained in the casing.

Abstract: 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.

Abstract: 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.

Abstract: 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.