Patent · US Expired

Drive system for two pairs of wheels

US4895217A · kind A · utility

56Cited by

8References

14Claims

0Family size

Assignee

Deere & Company · US

Inventors

Volker Hueckler · Radolfzell, DE
Dieter Nobis · Neuss, DE
Reinhard Schwarz · Garching bei München, DE

Key dates

Filing date	Dec 21, 1987
Grant date	Jan 23, 1990
Priority date	—
Expiry date	Dec 21, 2007

Classification

Technology area (CPC B)Performing Operations; Transporting
CPC primaryB60W2540/18
WIPO fieldTransport
WIPO sectorMechanical engineering

Abstract

A drive system for a four-wheel drive motor vehicle, in particular an agricultural tractor, includes a gradually lockable differential for the front wheels, a gradually lockable differential for the rear wheels, and a gradually lockable center differential in the drive to the front and rear differential gears. The degree of locking of the respective differentials is controlled by a control circuit based upon their relative rotational speeds, the steering angle and the temperature in the center differential. In an alternative embodiment, brakes on each wheel and on the shafts connecting the center differential to the front and rear differential are used to supplement or replace the differential locks.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.