Abstract: The present disclosure describes a method for memory cell placement. The method can include placing a memory cell region in a layout area and placing a well pick-up region and a first power supply routing region along a first side of the memory cell region. The method also includes placing a second power supply routing region and a bitline jumper routing region along a second side of the memory cell region, where the second side is on an opposite side to that of the first side. The method further includes placing a device region along the second side of the memory cell region, where the bitline jumper routing region is between the second power supply routing region and the device region.

Abstract: An external circulation type ball screw with a noise-reduction structure is provided with a noise-reduction cover to be mounted on the nut. The noise-reduction cover is defined with a noise-reduction groove with two ends to cover impacting portions of the return path of the return member where the rolling elements impact the return path. With the design of the noise-reduction groove, noises will counteract each other after being transmitted to the noise-reduction groove, thus reducing the noises produced by the rolling elements impacting the return member and accordingly reducing the noises produced during operation of the ball screw.

Abstract: An external circulation type ball screw with a noise-reduction structure is provided with a noise-reduction cover to be mounted on the outside of the nut. The noise-reduction cover is defined with a noise-reduction groove with two ends located correspondingly to impacting portions of the return path of the return member where the rolling elements impact the return path. With the design of the noise-reduction groove, noises will counteract each other after being transmitted to the noise-reduction groove, thus reducing the noises produced by the rolling elements impacting the return member and accordingly reducing the noises produced during operation of the ball screw.

Abstract: A roller screw with a circulating structure mainly comprises two circulating members and a return pipe. Each circulating member includes a return path that is rotated relative to a tangent plane tangent to the circumference of the helical groove of the nut, and the cross section of each return path is square-shaped. The return pipe is formed with a guiding route having a square-shaped cross section, and both ends of the guiding route are connected to the return paths of the circulating members, respectively. The return paths are connected to and tangent to the helical grooves, and an angle between the tangent surfaces is approximately 90 degrees.

Abstract: An external circulation type ball screw comprises a screw, a nut, rolling elements and a return member. The nut is a hollow structure mounted on the screw. The rolling elements are received in the helical groove of the screw and the rolling groove of the nut. The return member is disposed on the nut and includes a guiding member and a cover. The guiding member is defined with two guiding portions and a first half pipe, and each guiding portion is fixed in the fixing hole of the nut. The cover includes a fixing portion for covering the guiding portion and a second half pipe for covering the first half pipe. The return member is installed in the fixing hole through the guiding portion, and then the cover is used to cover the guiding member, thus finishing the assembly of the return member. In addition, the return device can be produced by molding process, and it solves the problem that the conventional return device is difficult to assemble.

Abstract: A ball screw device includes a screw shaft rotatably engaged with a ball nut, and a number of bearing members received between the ball nut and the screw shaft, and a circulating device for circulating the bearing members, the circulating device includes a tubular member having two end blocks for engaging into the ball nut and having a passage for receiving the bearing members, and having an anti-symmetric structure formed by two half members, and each half member is formed by two half segments each having a portion of the passage of the half member for allowing the half segments of the half member to be precisely formed with molding processes.

Abstract: An external circulation type ball screw comprises a screw, a nut, rolling elements and a return member. The nut is a hollow structure mounted on the screw. The rolling elements are received in the helical groove of the screw and the rolling groove of the nut. The return member is disposed on the nut and includes a guiding member and a cover. The guiding member is defined with two guiding portions and a first half pipe, and each guiding portion is fixed in the fixing hole of the nut. The cover includes a fixing portion for covering the guiding portion and a second half pipe for covering the first half pipe. The return member is installed in the fixing hole through the guiding portion, and then the cover is used to cover the guiding member, thus finishing the assembly of the return member. In addition, the return device can be produced by molding process, and it solves the problem that the conventional return device is difficult to assemble.

Abstract: A screw shaft device includes a screw shaft having an outer helical groove and having an intermediate portion, the screw shaft includes a longitudinal bore, a ball nut is threaded with helical groove of the screw shaft, and a number of ball bearings or rolling members are disposed between the ball nut and the screw shaft for facilitating a movement of the ball nut relative to the screw shaft, an inserted member is disposed in the intermediate portion of the longitudinal bore of the screw shaft, and the other inserted members are disposed in the end portions of the screw shaft, and the inserted member are made of different materials.