Patent ID: 7500409

Claim:
A seal for a ball screw including a ball screw shaft, a ball screw nut and a number of balls accommodated between the ball screw shaft and the ball screw nut, in which the ball screw shaft has an outer peripheral surface on which a ball rolling groove is formed and the ball screw nut has an inner peripheral surface on which a ball rolling groove corresponding to the ball rolling groove of the screw shaft is formed, said seal for the ball screw being disposed at each of both end portions of the ball screw nut and comprising: a foreign material removing member formed in a shape of a thin plate and having a hole of a shape corresponding to a sectional shape of the ball screw shaft taken perpendicularly to an axis thereof to prevent foreign material from invading from an outside of the ball screw nut to an inside thereof, a seal member formed in a shape of a thin plate and having a hole of a shape corresponding to a sectional shape of the ball screw shaft taken perpendicularly to an axis thereof to retain lubricant existing inside the ball screw nut, said seal member being formed from a lubricant absorbing material; and said foreign material removing member and said seal member being mounted to the ball screw shaft while being overlapped to each other in a state that inner peripheral portions of the foreign material removing member and the seal member contact an outer peripheral surface of the ball screw shaft and the ball rolling groove thereof, said foreign material removing member being disposed outside the seal member in the axial direction of the ball screw nut, wherein said seal member is formed from soft material and said foreign material removing member is formed from a material harder than the material of the seal member.