Drive system of a utility vehicle

US7044257B2 · kind B2 · utility

Assignee

• Deere & Company · US

Inventors

• Bernd Kempf · Alzenau, DE
• Jürgen Hofer · Großbundenbach, DE
• Stefan Bohrer · Sankt Wendel, DE

Key dates

• Filing date: Mar 14, 2003
• Grant date: May 16, 2006
• Expiry date: Apr 29, 2023

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16H2059/683
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A drive system for use in utility vehicles, such as agricultural forage harvesters and combines, includes a hydrostatic transmission having a pump driven by a main engine of the vehicle and having first and second motors respectively coupled to front and rear axles of the vehicle by way of first and second differential gear sets. The pump and one or both of the motors have a variable displacement determined by positioning respective swash plates through the agency of a lever, in the case of the pump, and by electronic devices, in the case of the motors, the electronic devices acting in response to control signals sent by a control arrangement, which in turn, operates in response to signals produced by pressure sensors associated with the motors and by signals produced by speed sensors associated with output shafts of the hydraulic motors. The control arrangement has a memory for storage of data, such as maximum legal ground speed and the ratio of the speeds of the axles as results from a given wheel size, and uses this information for controlling the hydrostatic transmission such that the vehicle does not exceed the speed, and the front and rear axles are driven so as to produce th…