Design of Automotive Magneto-rheological Fluid Dual-clutch

Abstract

To fulfill the requirement of the torque transmission for the medium and small displacement vehicles, design a magneto-rheological fluid dual clutch (MRDC). MRDC adopts magneto-rheological effect of magneto-rheological fluid (MRF) to transmit torque. Only by changing the current in the coil, the separation and combination of the clutch is realized. This new type of dual clutch has the characteristics of no wearing, low energy consumption, high control accuracy, fast response and simple structure. Its working process is introduced and the relationship between the torque and the magnetic flux density is obtained. Introduction Dual Clutch Transmission (DCT) is a mechanical automatic transmission and has been widely applied on automobiles [1,2]. It was developed based on manual transmission (MT). A car equipped DCT has a lower fuel consumption than AT. The core component of the DCT is the dual clutch. It is composed of two clutches, the active part is connected to the engine crankshaft and the driven parts of the two clutches are connected respectively to the two input shafts (internal and external) of the gearbox. The two input shafts are decorated respectively with odd and even gears. There has no power interruption during shifting. But the structures of the dual clutch and the control valves are complicated and have high requirements on machining accuracy. The service life of the friction pieces is short and has a high requirement. This looks forward to a new type of dual clutch with simple structure, reliable operation, small wear, high controllability and fast response. Magneto-rheological fluid (MRF) is a kind of intelligent material. Without magnetic field, MRF flows like fluid; while under magnetic field, it shifts into Bingham plastic solid and forms chain-structure within millisecond level. This phenomenon is called magneto-rheological effect [3,4,5,6]. Magneto-rheological clutch (MRC) uses magneto-rheological effect to replace traditional friction to transmit torque. In this paper, we designed a magneto-rheological fluid dual clutch (MRDC), which could fulfill the requirement of the torque transmission for the medium and small displacement vehicles, to replace the traditional friction dual clutch [7]. Only by changing the current in the coil, the separation and combination of the clutch is realized. The Structure Design of MRDC The assembly drawing of MRDC is shown in figure 1 and the sectional view of the three-dimensional model is shown in figure 2. The structure has a drive shaft and two driven shafts. The two clutches (the internal and external clutch) are placed nested in radial. The maximum radius is 258 mm. The drive shaft is connected to the engine crankshaft and the driven shafts of the two clutches are connected respectively to the two input shafts of the gearbox. The drive cylinders and the drive shaft are connected by welding; the driven cylinders and the middle plate are welded. The gap between the drive and driven cylinders is filled with MRF. 1 Supported by Beijing Natural Science Foundation (3152023) and Military Scientific Research Project 3rd International Conference on Mechanical Engineering and Intelligent Systems (ICMEIS 2015) © 2015. The authors Published by Atlantis Press 601 Fig.1 The assembly drawing of MRDC 1-drive shaft; 2-deep groove ball bearing; 3-lip-type packing; 4-cover; 5-drive cylinders; 6-driven cylinders; 7-shell of the internal clutch; 8,9-O ring; 10,13,16,17,21-socket head cap screw; 11-shell of the external clutch; 12,19-middle plate; 14,18-coil; 15,22-driven shaft of the external clutch; 20-coil cover; 23-driven shaft of the internal clutch; 24-screw bolt and cap. Fig.2 The sectional view of the three-dimensional model