The invention relates to a valve digital display device which can display the switch conditions of variable valves, as displaying the switch rings and calculating the flow via the flow parameter. The invention utilizes friction contact drive theory. The dial disc and the valve rod can form a transmission system via the friction wheel. It can solve the problems of present gear transmission system as mesh slit, mesh dead zone, the error caused by idle rotation, and the error caused by the inaccurate position of single-tooth dial display disc. |