The synchronizer device of manual transmissions is very important in respect to shift comfort and endurance. Shift comfort and endurance behaviour of the synchronizer are influenced by many parameters such as friction materials, friction surfaces, lubricant and mechanical characteristics,...The synchronization device is an essential component for manual transmission. Many gear-box components in this device are feasible by Powder Metallurgy (PM). FEDERAL MOGUL has experience in the design and manufacture of these synchronizer components. Some parts are in production : synchronization ring and hub, or are in development: sleeve, clutch body, gear. Today, the present trend of automotive manufacturers is to buy complete assembled functions such as the synchronization function. For testing behaviour of the synchronizer function, we need to run a large number of tests such as friction tests and endurance tests. To achieve this, FEDERAL MOGUL has realized specifics tests permitting the evaluation of the characteristics and the performances of a car gear-box synchronizer. The complete synchronizer function of a manual gear-box is tested under extreme load conditions or under loads representative of practical use. With this bench, we can analyse the behaviour or the failure of the synchronizer device by measuring the load on the sleeve, the rotational speed differential, the sleeve displacement, the synchronization torque and by calculating the apparent friction coefficient during the equalization stage. This paper describes the bench and the different tests and testing procedures used.
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