The present invention provides a kind of combined harvester threshing cylinder axle center bounce track testing devices, including coaxial mounted magnetic shell, magnetcisuspension paintbrush, chart and shaft end adsorbing mechanism, one end of magnetic shell to connect with one end of shaft end adsorbing mechanism；One end for being mounted on shaft end adsorbing mechanism on one side of chart；The suspension of magnetcisuspension paintbrush is fixed on inside magnetic shell, and the pen tip of magnetcisuspension paintbrush one end and the another side of chart offset.Magnetcisuspension paintbrush, which suspends, to be positioned, other parts rotate together with bounce with axis, paintbrush write down on grid chart turn upside down with actual axle heartbeat dynamic rail mark, the track figure line of left and right mirror image, finally grid chart, which is inserted into card reader, again can obtain amplifying upright axle center bounce track.Present invention can apply to test the bounce state of all kinds of rice combine threshing cylinders, existing cylinder shaft heartbeat can solve using the present invention and move problem of the test device easily with cylinder shaft friction damage.
