The Sonnax mechanical diode GM-MD-3 with one-strut engagement, five-strut design offers much greater strength than existing roller clutches and “dog bone” style sprags. This design offers greatly increased reliability, especially where high torque, vibration or high overrunning speeds decrease the effectiveness of wedging-type, one-way clutches.
Positive engagement is achieved when the angled struts are automatically forced into a fully engaged position, eliminating torsional wind-up, minimizing engagement impact and prolonging component life. The design transfers force in a more direct fashion through planar strut arrangement and a shallow engagement angle, resulting in relatively small radial forces when compared to friction-actuated, one-way clutches.
Similar diodes include, GM-MD-9-3, a three-strut engagement, nine-strut design, and GM-MD-10S, a two-strut engagement, 10-strut design.
This unique design for a one-way clutch assembly known as the "Mechanical Diode®" (MD) was developed by Epilogics, Inc. in 1991 and was first introduced to torque converter rebuilders by Sonnax in 1997. The MD overrunning clutch, or freewheel, offers much greater strength than existing roller-ramps and sprags.