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Double Clutch Systems

Made-to-Order Double Clutch Systems

I. Introduction

II. Wet double clutch product portfolio

Figure 1 Half section of a wet double clutch with actuation bearings

Figure 2 Half section of a wet double clutch with internal ratio on subclutch 2

Figure 3 Half section of a wet double clutch with rotary feedthroughs and rotating cylinders

III. Dry double clutch product portfolio

Figure 4 Half section of two double clutches with wear adjuster

Figure 5 Half section of a dry double clutch without wear adjustment

IV. Friction linings for double clutches

Figure 6 Comprehensive approach to the development of Schaeffler’s wet friction lining

Figure 7 Benchmark results for the dynamic friction coefficient of Schaeffler’s wet friction lining and a competitor product (new and after endurance test)

Figure 8 Schaeffler’s wet friction lining as a one-layer design (left) and the new development approach with a two-layer wet running friction material (right)

Figure 9 Comparison of dynamic friction coefficients of the one-layer and two-layer Schaeffler friction lining after 15,000 uphill starts at full load

Figure 10 Comparison of tribological system damping

V. Actuator portfolio

Figure 11 Portfolio of Schaeffler actuators: Hydrostatic clutch actuator, lever actuator and transmission actuator

VI. System expertise

Figure 12 Torque characteristics of leakage-free systems with regard to controllability of the touch point

Figure 13 Determination of the touch point by means of the pressure-travel characteristic curve of a double clutch system

Figure 14 Driving profiles and load spectra worldwide, determined in a separate driving profile and broken down by city, freeway, highway and uphill starts (customer usage profile – CUP)

Figure 15 Components analyzed and their power losses

Figure 16 Power losses compared to “Hydraulic”, “Power pack” and “Hydrostatic” systems at an average speed of 1,000 rpm and 1,800 rpm in relation to the crankshaft

Figure 17 Drag loss measurements of engagement bearings and rotary feedthrough

VII. Requirements for modern powertrains

Figure 18 System comparison

Figure 19 Ejector pump including measurement of the amplification factor of the volume flow

VIII. Summary and outlook

The digital version of the Schaeffler Symposium 2018 “Mobility for Tomorrow” conference transcript