| 摘要 |
PURPOSE:To control the thickness of an oil film on the engaging surfaces of worm and rack by providing a spiral gear rotating integrally with the worm and movably controlling a shaft for mounting the gear engaging in mesh with the spiral gear. CONSTITUTION:Gears 8, 9 of oppositely threaded are mounted on worms 2, 3, respectively engaging in mesh with a rack 1 to engage in mesh with gears 10, 11, respectively. A spline 14 is formed at the left end of a shaft 12 for mounting the gears 10, 11 to engage in mesh with a wheel 15. A distributor 7 is provided at the body to supply lubricating oil to the engaging surfaces of the rack 1 and worms 2, 3. A shaft position controller 21 is provided at the spline 14. When the shaft 12 is axially moved by rotating the collar of the controller 21, the gears 10, 11 are moved to allow the gears 8, 9 to reversely rotate to each other to thereby cause the worms 2, 3 to reversely displace to each other at the teeth surfaces thereof to thereby control the thickness of an oil film. |
