Some different types of clutches are the positive clutch, friction clutch, hydraulic clutch, spring clutch and centrifugal clutch. Other types of clutches include the semi-centrifugal clutch and the electromagnetic clutch. These types of clutches are found in power trains that may have automatic or manual transmission systems.
The purpose of a clutch is to allow the driver of a vehicle or on-board computer system to select when the wheels are receiving power from the engine. A positive clutch, or dog clutch, is a straightforward type of clutch where grooves are engraved into each clutch half. When the halves come together, they lock in place and allow the engine to transmit power to the wheels. A friction clutch system differs in that the parts involved do not contact each other directly but uses a friction pad surface between them. Different types of friction clutches include cone clutches, single plate clutches, multi-plate clutches and diaphragm clutches.
A spring clutch uses tightly wound springs between the cover and pressure plate to apply force against the pressure plate that then engages the clutch. Centrifugal clutches use sprung parts but only engage at speed. The centrifugal force causes the clutch to spin and grab a clutch bell that then sends power to the wheels. Centrifugal clutches tend to work better at high speeds.