INTERNATIONAL^ 400 COMMONWEALTH DRIVE, WARRENDALE, PA 15096-0001 U.S.A. A Transmission Control System for Construction Machinery Kohei Kusaka and Yasunori Ohkura Technical Dept. Komatsu Ltd. International Off-Highway & Powerplant Congress and Exposition Milwaukee, Wisconsin September 10-1 3, 1990 Downloaded from SAE International by University of New South Wales, Sunday, September 16, 2018The appearance of the ISSN code at the bottom of this page indicates SAE's consent that copies of the paper may be made for personal or internal use of speclic clients. This consent is given on the condition, however, that the copier pay a $5.00 per article copy.fee through the Copyright Clearance Center, Inc., Operations Center, 27 Congress St., Salem, MA 01 970for copying beyond that permitted by Sections 107or 108 ofthe U.S. Copyright Law. This consent does not extend to other kinds of copying such as copying for general distribution, for advertising or promotional purposes, for creating new collective works, or for resale. SAE routinely stocks printed papers for a period of three years following date of publication. Direct your orders to SAE Customer Service Department. To obtain quantity reprint rates, permission to reprint a technical paper or permission to use copyrighted SAE publications in other works, contact the SAE Publications Group. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior writ- ten permission of the publisher. ISSN 01 48-71 91 Copyright 1990 Society of Automotive Engineers, Inc. Positions and opinions advanced in this paper are those of the Persons wishing to submit papers to be considered for presen- author@) and not necessarily those of SAE. Theauthor issolely tation or publication through SAE should send the manuscript responsible for the content of the paper. A process is available or a 300 word abstract of a proposed manuscript to: Secretary, by which discussions will be printed with the paper if it is Engineering Activity Board, SAE. published in SAE Transactions. For permission to publish this paper in full or in part, contact the SAE Publications Division. RMed In USA Downloaded from SAE International by University of New South Wales, Sunday, September 16, 2018ABSTRACT A Transmission Control System for Construction Machinery Kohei Kusaka and Yasunori Ohkura Technical Dept. Komatsu Ltd. This article describes a new transmission control system for off-highway dump trucks with small electro-hydraulic control valves which are individually equipped for each clutch. The new system mainly improves shift shocks by generating suitable clutch pressure curves while shifting. This system has some important technical points. The first one is the mechanism of the small electro-hydraulic control valve. It has two spools. One spool controls clutch pressure, and another controls oil flow and senses oil pressure. This valve recognizes the moment at which the clutch pack is filled up. It enables us to control not only the pressure curves of clutches, but also the timing of engagement and disengagement of clutches. Next technical point is that every clutch is equipped with one valve. Since one valve holds the pressure of a clutch which is being disengaged until another clutch, which is controlled by another valve, is filled up, we can keep driving torque while shifting. We developed so called "Torque-continuous shifting". The last point is that the clutch pressure is controlled according to driving condition by an electronic control system. Using this system, we can easily get the most suitable clutch pressure for any driving condition. One drawback of using electronic system is that it is a little troublesome for mechanics to repair or to do trouble shooting. To make the repairwork easier, we provided a self diagnosis system, which also memorizes troubles in the past in a non-