Abstract: Provided is a screw shaft in a ball screw device. At least a part of the screw shaft includes a cylindrical body which is manufactured by a filament winding method or a sheet winding method, and a spiral member or a partitioned spiral member which is fixed to an outer circumferential surface of the cylindrical body and forms a thread groove.

Abstract: A ball screw device includes: a threaded shaft; a nut; multiple first balls rollably arranged on a helical raceway composed of a helical groove of the threaded shaft and a helical groove of the nut; an inner ring raceway groove formed on an outer circumferential surface of one axial end of the threaded shaft; an outer ring having an outer ring raceway groove that faces the inner ring raceway groove; and multiple second balls rollably arranged between the inner ring raceway groove and the outer ring raceway groove. The ball screw device converts rotation of the threaded shaft into linear motion of the nut through the first balls rolling on the helical raceway while being subjected to a load. The outer ring has a rolling element insertion hole penetrating from its outer circumferential surface to the outer ring raceway groove and a lid configured to cover the rolling element insertion hole. An inner surface of the lid is formed into a concave shape to serve as part of the outer ring raceway groove.

Abstract: Provided is a screw shaft in a ball screw device. At least a part of the screw shaft includes a cylindrical body which is manufactured by a filament winding method or a sheet winding method, and a spiral member or a partitioned spiral member which is fixed to an outer circumferential surface of the cylindrical body and forms a thread groove.

Abstract: A ball screw apparatus is provided which is less likely to increase dynamic friction torque even when a nut is contracted by cooling, and in which cooling effect is made as high as possible and which does not invite excessive machining efficiency droop and increase in pressure loss. The ball screw apparatus includes a screw shaft, a nut screwed with the screw shaft via a plurality of balls, and a cooling section cooling the nut. The plurality of balls to which preload is applied in a two-point contact state, with a preload direction as a tensile direction, are disposed between a screw groove of the screw shaft and a screw groove of the nut. Or, a ratio of the axial length L of the through hole axially formed in the nut and the diameter D of the through hole axially formed in the nut is given by an equation “10?L/D?60”.

Abstract: A ball screw apparatus is provided which is less likely to increase dynamic friction torque even when a nut is contracted by cooling, and in which cooling effect is made as high as possible and which does not invite excessive machining efficiency droop and increase in pressure loss. The ball screw apparatus includes a screw shaft, a nut screwed with the screw shaft via a plurality of balls, and a cooling section cooling the nut. The plurality of balls to which preload is applied in a two-point contact state, with a preload direction as a tensile direction, are disposed between a screw groove of the screw shaft and a screw groove of the nut. Or, a ratio of the axial length L of the through hole axially formed in the nut and the diameter D of the through hole axially formed in the nut is given by an equation “10?L/D?60”.

Abstract: To surely and easily secure a return tube to a nut and prevent the return tube from floating and expanding when circulating failure of balls occurs. The ball screw device has a screw shaft having a helical shaft raceway groove on the outer face thereof, a nut having a nut raceway groove on the inner face so as to oppose to the shaft raceway groove, a load path formed by the shaft raceway groove and the nut raceway groove, balls rotatably mounted in the load path, a communicating member communicating both ends of the load path to guide the balls exterior of the nut and having a bent portion; a tube fixture for fixing the communicating member to the nut and a reinforcement member for receiving stress applied to the bent portion of the communicating member on an outer face of the tube fixture.

Abstract: A belt type infinite variable-speed drive using a ball-screw mechanism is compact and noise-free. A nut of the ball-screw mechanism is fixed to a casing and a threaded shaft is rotatably coupled to a movable pulley member through a ball bearing so that ball circulating portions on the nut will not rotate while the movable pulley member is movable axially. Also, the ball circulating portions, which are low in load bearing capacity, are oriented in such a direction that a load hardly acts on the ball-screw mechanism. This makes it possible to compactly and rationally design a belt type infinite variable-speed drive and to suppress noise due to vibration of balls in the ball circulating portions.

Abstract: A belt type infinite variable-speed drive using a ball screw is proposed which is compact and noise-free. The nut of the ball screw mechanism is fixed to a casing and the threaded shaft is rotatably coupled to a movable pulley member through a ball bearing so that ball circulating portions on the nut will not rotate while the movable pulley member is movable axially. Also, the ball circulating portions, which are low in the load bearing capacity, are oriented in such a direction that load hardly acts on the ball screw mechanism. This makes it possible to compactly and rationally design a belt type infinite variable-speed drive and to suppress noise due to vibration of the balls in the ball circulating portions.

Abstract: An injection unit driving device or an mold-clamping unit driving device having a ball screw having a long life. Of the parts of the ball screw, only the balls are subjected to carburizing/nitriding treatment, while the threaded shaft and the nut are subjected to conventional hardening.

Abstract: A plurality of balls 3 are disposed for rolling and circulation in a spiral calculation passage defined between a spiral screw groove surface 1a formed on the outer periphery of a screw shaft 1 and a spiral screw groove surface 2a formed on the inner periphery of a ball nut 2. The opposite ends of the ball nut are each formed with a seal mounting portion 2b, in which a seal member 4 made of solid lubricating composition is mounted, sealing off the ball nut 2. The ball nut 2 has lubricating grease G sealed therein.

Abstract: A ball screw for a vacuum apparatus which includes a screw shaft having a spiral inner raceway formed on an outer peripheral surface thereof, a ball nut having a spiral outer raceway formed on an inner peripheral surface thereof, a plurality of balls disposed in a spiral space defined between the inner raceway and the outer raceway, and circulating members connecting ends of the spiral space to each other to define a continuous ball circulating passage. The plurality of balls are first balls formed of high polymer material containing polytetrafluoroethylene as a main component and second balls formed of either a metallic material or a ceramic material. The first balls circulate through the circulating passage together with the second balls. The second balls have lubricating films of crystalline polytetrafluoroethylene formed on the surface thereof.