Shiotsu, I., Hayakawa, K., and Nishizawa, H., "Performance Validation of Engine Starter Utilizing Feed Screw Mechanism," SAE Technical Paper 2016-01-1066, 2016, doi:10.4271/2016-01-1066.
A new engine starter is developed for the purposes of downsizing and improving response time. A feed screw is used in the proposed starter, and its behavior is as follows. The motor shaft connected to the feed screw rotates, and the pinion gear with an internal screw then moves along its axis and stops at the end of the screw. The ring gear connected to the engine is located at the same axial position at which the pinion gear stops. Therefore, the pinion gear is engaged with the ring gear, and the engine is turned over. While a conventional starter requires a solenoid actuator to move the pinion gear, this device does not because the rotational movement of the screw is converted to the axial movement of the pinion gear. However, there is a problem whereby the rotational speed of the motor shaft decreases when the gear pair is engaged. This problem is resolved by adding a coil spring between the pinion gear and the end of the screw. Comparative tests were conducted to examine the response time. The test results reveal that the response time of the proposed engine starter is 15% faster than that of a conventional engine starter. Moreover, the proposed engine starter is approximately 10% smaller than a conventional engine starter.