Patent ID: 8893572

Claim:
A backlash eliminating device for helical gears, wherein the backlash eliminating device for helical gears is used in a gear transmission system comprising two helical gears and a match gear engaged with the two helical gears, the backlash eliminating device comprising: a sleeve being coaxial with the two helical gears and having two extremity parts, wherein the two extremity parts are respectively connected to the two helical gears, so that a predetermined gap is formed between the two helical gears, and at least two sections of spiral grooves are formed between the two extremity parts of the sleeve, each section of spiral grooves penetrates a peripheral surface of the sleeve and surrounds the sleeve for at least two circles to form at least two sections of spiral sheet structures, wherein, each section of spiral sheet structures provides a preload spring force along an axial direction, so that the two helical gears are engaged with the match gear without leaving any backlash.