Infinitely Variable Transmission (IVT) of John Deere 7000 TEN Series Tractors

Abstract

The John Deere 7000 TEN series tractors represent a significant change in the transmission system compared to previous John Deere tractor models in this category. John Deere 7710 and 7810 series tractors are the first of the 7000 TEN series tractors offering an infinitely variable transmission (IVT). These tractors provide infinite vehicle speeds in the forward mode from 50 meters/hr to 40 km/hr or an optional 50 km/hr. Reverse mode provides infinite vehicle speeds from 50 meters/hr to 17 km/hr. The IVT provides performance improvements in several areas for unmatched operator convenience and control. The new IVT uses an electric signal to control the electro-hydraulic hydrostatic system with mechanical power train. The IVT represents a hydro-mechanical transmission system using electronics, hydraulics and mechanical systems’ integration to achieve the required performance. This paper describes the IVT system configuration, components, operation, characteristics and some of the engineering considerations dealt with in the development process. The overall IVT system truly represents a “drive-by-wire” mechatronic design.

Advanced Design and Optimal Sizing of Hydrostatic Transmission Systems

“…More significant is the effort made by researchers in the fluid power community towards the proposal of modifications of the basic HT schematic aimed at improving the system efficiency. After the first pioneer work published by the John Deere company [11,12] several HT architectures based on the so-called hydromechanical power-split architecture were proposed. A hydromechanical power split uses a planetary gear train to merge an HT with a mechanical drive in a single transmission.…”

Control of Hybrid Hydromechanical Transmissions

“…In the case of larger machines, more complex solutions may be applicable so that one or several of the modes are of the power-split configuration. For agricultural tractors, non-hybrid multiple-mode power-split HMTs have been state-of-the-art for some time [32,33] and commercialised concepts for construction machines exist on the market as well [34,35].…”

Hydraulic power sharing on a hydrostatic transmission for a load–haul–dump for underground mines

“…8 Other examples of HSTs include a compact transmission for small mobile equipment such as forklifts and telehandlers 9 and a HST by Poclain that allows customisation of system parameters through an interface between a personal computer and the HST controller. 10 The inefficiency of HSTs was addressed by the use of a mechanical gearbox to increase the overall efficiency of the transmission 11 and a computer controller to optimise the fuel efficiency of the primary mover, in this case a diesel engine. 12 The latter example was applied to a city bus where the low clearance of the bus floor above the ground (0?325 m) precluded the use of a mechanical transmission.…”