Patent ID: 6092434
Filing Date: 2000-07-25
Classification: F16H,Y10T

Abstract:
A ball-circulating-part embedded ball screw device, comprising:a screw shaft having a helical thread groove on an outer peripheral surface thereof;a ball nut having an engaging portion on an outer peripheral surface thereof and a thread groove provided on an inner peripheral surface thereof in correspondence with the helical thread groove of said screw shaft, said screw shaft being loosely fitted in the inner peripheral surface of said ball nut;a multiplicity of balls rotatably fitted between the two thread grooves;a ball-circulating member fitted in said ball nut for defining an endless rolling passage in which said balls are circulated while said balls are being guided by said ball-circulating member, at least a portion of a fitted outward surface of said ball-circulating member being substantially flush with the outer peripheral surface of said ball nut in a vicinity of the fitted outward surface of said ball-circulating member; anda holding member for fixing said ball-circulating member to said ball nut by being fitted over the outer peripheral surface of said ball nut and covering the fitted outward surface of said ball-circulating member, said holding member having an engaged portion which is engaged with said engaging portion of said ball nut so as to prevent the holding member from being moved relative to said ball nut in the axial direction thereof,wherein said engaging portion of said ball nut comprises a retaining recess formed on the outer peripheral surface thereof; andsaid engaged portion of said holding member comprises a projection member formed on the inner peripheral surface thereof and engaged with said retaining recess.