Patent ID: 8132478

Claim:
A motion guide apparatus comprising: an elongated shaft including a helical groove formed on an outer peripheral surface thereof, a ball nut movably attached onto said elongated shaft, and including a bore formed therein and defined by an inner peripheral surface for receiving said elongated shaft, and including a helical groove formed in said inner peripheral surface thereof, a ball circulating device attached to said ball nut for forming an endless ball guiding passage between said ball nut and said elongated shaft, a plurality of ball bearing elements received and engaged with said endless ball guiding passage, and a ball coupler including a flexible coupling member having a plurality of openings formed between spacers for receiving and engaging with said ball bearing elements, and wherein said ball bearing element is contacted with said ball nut at a contact point which is spaced from said inner peripheral surface of said ball nut for a spacing distance (C 1 ), and said ball bearing element is contacted with said screw shaft at a contact point which is spaced from said outer peripheral surface of said screw shaft for a spacing distance (C 2 ), and said spacing distance (C 2 ) between said contact point of said ball bearing element and said screw shaft is smaller than said spacing distance (C 1 ) between said contact point of said ball bearing element and said ball nut.