US 4,860,612 A · Vehicle torque transfer case for a four wheel drive system

Abstract

A four wheel drive transfer case transmits power from the output of a vehicle transmission to front and rear differential assemblies. The transfer case includes an input shaft coupled to the output shaft of the vehicle transmission, and an interaxle planetary gear differential for dividing power between a rear output shaft connected to the vehicle rear differential and a front output shaft connected to the vehicle front differential. An electromagnetic friction clutch is located in the transfer case and is adapted to selectively lock the planetary gear differential to prevent slip between the front and rear output shafts. An electronic control is operative to selectively engage the electromagnetic clutch to lock the differential for a predetermined time period when a predetermined amount of slip is detected between the front and rear output shafts. In accordance with the present invention, a cross-axised gearing arrangement is utilized to provide an angled front output shaft which has a rotational axis oriented in non-parallel, non-intersecting relationship with the rotational axis of the rear output shaft. This arrangement provides a substantially straight line connection between the transfer case and the vehicle rear differential, and between the transfer case and the vehicle front differential. Also, a unique lubrication system is provided for supplying lubricating oil to the upper components of the transfer case.

Claims19

Dependent claims

A four wheel drive system for a vehicle having front and rear drive wheels and an engine and transmission assembly for providing a supply of output torque, said system comprising:

a torque transfer unit including a torque input shaft for receiving output torque from the vehicle engine and transmission assembly, a front output shaft, a rear output shaft, and means for drivingly connecting said torque input shaft to said front and rear output shafts;
said front output shaft having a rotational axis which is oriented in a non-parallel, non-intersecting relationship with the rotational axis of said rear output shafts;
said rotational axis of said front output shaft and said rotational axis of said rear output shaft cooperating to define skew lines;
a rear differential connected to drive the vehicle rear wheels and having a rear input shaft positioned lower than said rear output shaft of said torque transfer unit;
a rear drive shaft connected between said rear output shaft and said rear input shaft and angled downwardly from said rear output shaft to said rear input shaft;
said rear output shaft and said rear input shaft being oriented such that when the vehicle is loaded with a predetermined weight the angle between said rear drive shaft and said rear output shaft is substantially equal to the angle between said rear drive shaft and said rear input shaft;
a front differential having a front input shaft and connected to drive the vehicle front wheels;
a front drive shaft connected between said front output shaft of said transfer unit said front input shaft of said front differential;
and
said front output shaft and said front input shaft being oriented such that when the vehicle is loaded with said predetermined weight the angle between said front drive shaft and said front output shaft is substantially equal to the angle between said front drive shaft and said front input shaft.

7 more elements

A lubrication system for a four wheel drive transfer case comprising:

a housing;
an input shaft rotatably supported within said housing;
a rear output shaft rotatably supported within said housing;
a sleeve member coaxially and rotatably supported about said input shaft;
a first output gear secured for rotation with said sleeve member;
a differential means for dividing torque from said input shaft between said front and rear output shafts, said differential means having three interconnected components including a first component connected to said input shaft, a second component connected to said rear output shaft, and a third component connected to said sleeve member;
a front output shaft rotatably supported within said housing;
means for drivingly connecting said first output gear to said front output shaft;
said housing containing a supply of lubricating oil at least partially immersing said first output gear;
said first output gear located adjacent an upper front inside surface of said housing;
a front oil reservoir located above said input shaft;
said housing including a rib member located on said upper inside surface of said housing for receiving lubricating oil thrown against said rib by said first output gear as said first output gear is rotated, said rib member angled downwardly toward said front oil reservoir for directing lubricating oil into said front oil reservoir;
and
means for directing lubricating oil from said front reservoir through said sleeve member and into said differential means.

11 more elements

Dependencies are inferred from the claim text.

Vehicle torque transfer case for a four wheel drive system

Life of this patent

Vehicle torque transfer case for a four wheel drive system

Life of this patent

Abstract

Claims19