Design and development of gear shift cable on manual automotive transmissions

Thesis Type: Postgraduate

Institution Of The Thesis: Bursa Uludağ University, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2019

Thesis Language: Turkish


Supervisor: Yahya Işık


In this master thesis, firstly the history, definition, performance characteristics and the components of the mechanical gear shift cables were explained in detail. Subsequently, the demands and requirements of an automobile manufacturer regarding the shift cables were identified and all of the processes for the purpose of shift cable design were followed up carefully step by step. After the completion of the design steps of shift cables, studies have been performed in order to bring the solutions to problems which cause the performance decrease and by this way cable was developed. One of the problems which is solved in this thesis is that the cable cannot withstand the required loads during the breaking strength test in its design approval phase due to its low compression load resistance. In this first study, the breakage occurred in 1400 N range where the target is minimum 500 N from on top of the knob (force application point) (Ratio= 3,13 and 500x3,13=1565 N to cable) After the design changes implemented in the shift cable in order to solve the problem, breakage loads were increased up to 1900N. The second problem is that the shift cable has more friction resistance (NLSR) than the required target. This situation creates the non-conformity during the gear shifting and undesirable feelings for the driver. The maximum friction resistance of the shift cable on real vehicle routing which is requested 9,83 N. Nevertheless, the friction of the cable was around 15 – 16 N. After the design improvement studies, friction values of the cable was reduced down to around 7 N.