TENSILE FORCE ADJUSTMENT DEVICE FOR CAM SHAFT DRIVING TIMING BELT OF INTERNAL-COMBUSTION ENGINE

摘要

PURPOSE:To enable a cam shaft to be driven with appropriate timing by putting an idle pulley in forward and backward movement in response to a change of the temperature in an adjustment device for the extension of a timing belt which drives a cam shaft of an internal-combustion engine. CONSTITUTION:A step motor 32 is connected to an electronic control device 33 such as a computer and the like. The engine temperature is measured by a thermometry sensor 34. The electronic control device 33 gives an indication signal to a step motor 32 on the basis of a signal from the thermometry sensor 34. Accordingly, operation of the step motor 32 adjusts the position of an idle pulley 8 through moving a lever 30 in the direction of an arrow or in the reverse direction according to the advance or retreat movement of a spindle. Since the timing belt extension can thus be maintained in almost a constant level at temperatures ranging from high to low, a cam shaft can be driven with an appropriate timing.