Crawl ratio

About: Crawl ratio is a research topic. Over the lifetime, 686 publications have been published within this topic receiving 7311 citations.

Development of a high performance magnetic gear

Abstract: This paper presents calculation and measurement results of a high-performance permanent-magnetic gear. The analyzed permanent-magnetic gear has a gear ratio of 5.5 and is able to deliver 27 N/spl middot/m. The analysis has shown that special attention needs to be paid to the system where the gear is to be installed because of a low natural torsion spring constant. The analyzed gear was also constructed in practice in order to validate the analysis and predict the efficiency. The measured torque from the magnetic gear was only 16 N/spl middot/m reduced by the large end-effects. A systematic analysis of the loss components in the magnetic gear is also performed in order to figure out why the efficiency for the actual construction was only 81%. A large magnetic loss component originated in the bearings, where an unplanned extra bearing was necessary due to mechanical problems. Without the losses of magnetic origin in the bearings and less end-effects caused by relatively short stack, an impressive efficiency estimated at 96% can be obtained. Comparison with classical mechanical gears has shown that the magnetic gear has a better efficiency and a comparable torque per volume density. Finally, it is concluded that the results in this paper may help to initiate a shift from mechanical gears to magnetic gears.

Speed change gear system

Abstract: A speed change gear system for providing at least four forward drive speed ranges and one reverse drive speed range includes planetary gear sets of the single-pinion type and simple planetary gear sets of the double-pinion type as well as a plurality of clutches and brakes. As a result of the coupling and uncoupling of the clutches and brakes, the movable elements of the gear sets are suitably coupled so as to attain the various speed ranges.

Planetary gear type transmission system

Abstract: In a planetary gear type transmission system for seven forward speeds and one rearward speed, a high speed stage gear train is disposed on an input side of a low speed stage gear train, a low speed use rotary clutch in the low speed stage gear train is constructed so as to directly couple a ring gear in the high speed stage gear train with a carrier in the high speed stage gear train, a first speed stage gear train is disposed on an output side of a second speed stage gear train, a carrier in the first speed stage gear train is coupled to an output shaft, and a fourth speed stage gear train, a third speed stage gear train and a reverse stage gear train are disposed between the low speed stage gear train and the second speed stage gear train.

Transmission clutch loop transfer control

Abstract: A method for controlling the transfer of load from one friction element to another friction element while making a gear ratio change in an automatic transmission. The synchronous engine speed is increased by slipping the offgoing clutch. A constant is calculated from known speed ratios of the gear set, engine inertia, the difference in engine speed from synchronous speed and a constant that corresponds to the output torque at the end of the torque phase of the gear ratio shift. The time rate of change of the offgoing clutch torque is calculated and the clutch pressures are changed in accordance with the calculated torque slope.