Abstract: A ball screw device includes a screw shaft threaded with a ball nut which has two channels and an opening, a guide member is engaged into the opening of the ball nut and has two curved pathways communicating with the channels to form two separated endless ball rolling passages in the ball nut, and two groups of bearing members are engaged in the two separated endless ball rolling passages for facilitating a movement of the ball nut relative to the screw shaft. The guide member includes two bars for enclosing the curved pathways of the guide member, and the bars each have a curved recess for forming the curved pathways of the guide member and for allowing the guide member to be easily manufactured.

Abstract: A ball screw assembly, wherein the circulate component is positioned in the nut by inserting a protrusion in a notch, so that the circulate component is positioned easily, and the problem of assembly difficulty is solved. The method of fixing the circulate components in the nut is that: the circulate component is formed with an axial hole and the radial hole that are connected to each other, the axial hole of the circulate component is aligned to the axial locking hole of the nut, and then liquid resin is injected into the axial hole of the circulate components, and the liquid resin will form a locking members after curing, thus fixing the circulate component in the nut. Due to the formation of the locking member is determined by the diameter of the hole to be machined, the configuration of locking member will be varied in response to the diameter of the hole to be machined. Whatever the diameter of the hole to be machined changes or not, it will not affect the interchangeability of the locking member.

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: An external circulation type ball screw is provided with a helical passage in the outer surface of the nut. The helical passage and the inner helical groove of the nut are opposite in winding direction to each other. The nut is defined with two through holes which are connected to both ends of the inner helical groove and the helical passage, respectively, so that the helical passage and the inner helical groove are connected to each other to form a circulating path for the circulation of the balls. Since the helical passage winds about the outer periphery of the nut, the balls can roll more smoothly.

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: A ball nut includes a nut member having an inner thread formed in a bore for threading with a screw member, the nut member includes a recess and an opening communicating with the bore of the nut member for forming one or more anchoring surfaces. A guiding device includes a shank received in the recess of the nut member, and one or more return channels formed in the shank for aligning with the inner thread of the nut member, and an anchoring bar on one end of the shank and engaged in the opening of the nut member. The anchoring bar has one or more end portions for engaging with the anchoring surface of the nut member and for securing the guiding device to the nut member.

Abstract: An internal circulation ball screw comprises a nut, a screw, a plurality of return assemblies, and a plurality of balls. The nut is threaded on the screw through the balls. An arc-shaped curving surface is formed on the edge of a tip of an outer thread of the screw and is to be connected to a return path of the return assemblies. The radius of the arc-shaped curving surface of the screw is between 9%-17% of the diameter of a ball, and each of the outer threads of the screw has three different curvature sections formed at the positions where the balls climb over, which are climbing curvature section, fillet curvature section and tip curvature section. By such arrangements, the internal circulation ball screw can allow the balls to move more smoothly and stably, and keep the balls from falling off or deflecting.

Abstract: A ball screw device includes a ball nut having a number of helical groove portions and one or more channels, a screw shaft having a number of helical groove portions for threading with the ball nut, and a number of rolling members engaged in the helical groove portions of the ball nut and the screw shaft for facilitating a movement of the ball nut relative to the screw shaft. Two or more guide members are engaged in the helical groove portions of the screw shaft, and each has a slot to form an endless ball rolling passage together with the helical groove portions and the channel of the ball nut and to slidably receive the rolling members. The guide members each includes a projection for engaging with and for anchoring to the ball nut.

Abstract: A linear motion apparatus has a guide shaft including a spiral-shaped or linear-shaped rolling element rolling groove, a movable body including a spiral-shaped or linear-shaped rolling element rolling groove opposed to the rolling element rolling groove of the guide shaft, a large number of rolling elements rollably moving along a rolling element rolling passage formed between the rolling element rolling grooves of the guide shaft and movable body and, a rolling element return passage communicating with the rolling element rolling passage, wherein, in the portion of the rolling element rolling groove of the movable body that is adjacent to an open end of a rolling element return passage, an escape portion is formed by abrasive flow machining in such a manner that the grinding depth thereof increases gradually toward the open end of the rolling element return passage.

Abstract: A roller screw system comprises a screw shaft, a nut, a pair of return members, a return pipe and a plurality of rollers. The nut is interiorly defined with a receiving recess for accommodation of the return members, and an abutting surface. The roller screw system is characterized in that a through hole is defined in the nut and is in communication with the return hole. The return pipe is disposed in the through hole of the nut. The return members are disposed in the receiving groove of the nut, forming a return system. And the return system is to be connected to the helical groove of the screw shaft and the nut, thus forming a roller screw system. By such arrangements, the rollers can circulate more smoothly and the size of the nut will not be increased.

Abstract: A ball screw apparatus includes: a screw shaft having a screw groove, a nut having a screw groove and holes, a number of balls rollably provided between the screw grooves, and a ball circulating member having an end portion to be fitted to the holes. The ball circulating member includes aside cap having leg portions to be fitted into the holes. Each of the leg portions contains a scooping up path or a returning path. The scooping up path and the retuning path are inclined with respect to outer peripheral faces of the leg portions. The holes include a slot substantially in parallel with directions of the screw grooves. The scooping up path and the returning path are directed substantially in a tangential direction of the screw shaft and inclined substantially toward a lead angle direction of the screw grooves.

Abstract: The outside diameter ? of a land portion 1c is set to be larger than a BCD. Thus, when a ball 3 goes into a deep portion (a portion close to an axis line O of a screw shaft 1), the land portion 1c of the screw shaft 1 guides the ball. Consequently, the circulation of the ball 3 can smoothly be performed.

Abstract: The invention relates to a ball screw device in which a screw shaft and a nut member are threadedly engaged with each other through a number of balls. In such a ball screw device, an inner surface of a cover plate contacting an end surface of a nut main body is provided with a projecting return piece adapted to be fit-engaged with a recess cut in an inner peripheral surface of the nut main body, the return piece being provided with a scoop portion for dislodging the balls from the ball rolling groove of the screw shaft and a direction switching passage for guiding the dislodged balls to the entrance of a ball return hole. The projecting return piece is divided into a first piece formed integral with the cover plate and a second piece fixed to the first piece by a curved plane including the center line of the direction switching passage.

Abstract: A ball screw device comprises a screw shaft, a nut externally mounted on the screw shaft, and a multiplicity of balls interposed between thread grooves of the screw shaft and the nut. The screw shaft has a ball circulation groove for coupling downstream and upstream sides of the thread groove so that the balls are returned from the downstream side to the upstream side and thereby circulated in the thread groove of the screw shaft. The ball circulation groove has such a curved shape as to sink radially inward in an intermediate region in a rolling direction of the balls and has a curved shape protruding radially outward in both end regions, and is configured in the manner that the centrodes of the balls rolling in the both end regions and the balls rolling in the thread groove of the screw shaft satisfy predetermined conditions with respect to circulation of the balls.

Abstract: In a ball screw drive comprising a spindle nut (2) that can be disposed on a spindle (1), said spindle nut (2) comprising on an inner periphery, a ball groove (3) that is arranged along a helix and defines a load-bearing channel (6) for balls (5), an external deflector (7) comprising a return channel (8) for the balls (5) being arranged on an outer periphery of the spindle nut (2), said external deflector (7) comprising two ball openings (E1, E2), each of which is connected to an end of the load-bearing channel (6) to deflect the balls (5) from one end of the load-bearing channel (6) to the other end of the load-bearing channel (6), the external deflector (7) extends from one of the two ball openings (E1) to the other of the two ball openings (E2) at least approximately over one full winding about an axis of rotation of the spindle nut (2).

Abstract: In a ball screw, a nut is fitted with the outer periphery of a screw shaft, ball rolling grooves opposed to each other are formed in the screw shaft and the nut The ball rolling grooves cooperate in forming a ball rolling path therebetween. A tube as a return path disposed on the nut for connecting one end portion of the ball rolling path to the other end portion thereof, the ball rolling path and tube cooperate in forming an endless circulation path. A plurality of load balls are disposed within the endless circulation path. The position of the tube cannot be limited to a single specific position. In the ball screw, retaining pieces are respectively inserted between the mutually adjacent ones of the load balls disposed within the endless circulation path.

Abstract: A screw feed apparatus has a screw shaft having a screw groove formed on the outer peripheral surface thereof; a nut having a screw groove formed on the inner peripheral surface thereof opposed to the outer peripheral surface of the screw shaft; a large number of rolling elements rollably interposed between the two screw grooves of the screw shaft and nut; a circulation path disposed in the nut for returning the rolling elements to their original positions; and, a deflector piece disposed in the nut for connecting the circulation path to a rolling path formed between the two screw grooves, wherein the deflector piece includes a plurality of divisional pieces respectively formed rolling element guide grooves cooperating together in forming a rolling element guide path for guiding the rolling elements to the circulation path.

Abstract: A ball screw has a screw shaft including a spiral-shaped ball rolling groove formed in an outer peripheral surface thereof; a nut including a spiral-shaped ball rolling groove formed in an inner peripheral surface thereof; a plurality of balls disposed in a raceway formed by the two rolling grooves; and, a return path for moving the balls from the terminal point of the raceway to the start point of the raceway, the two end portions of the return path respectively including a rising surface rising from the ball rolling groove of the nut and a stopper portion disposed opposed to the rising surface to form the end portion of the raceway, wherein a boundary portion between the rising surface and the ball rolling groove of the nut is formed a round portion having the radius of curvature 0.05 times the diameter of the ball or more.

Abstract: A circulation member of a ball screw for circulating a ball rolling on a spiral ball rolling groove formed on a screw shaft. The circulation member includes a central portion and a pair of leg portions disposed at both ends of the central portion so as to extend therefrom, the leg portions having inner peripheries having center lines inclined in directions different from each other with respect to a center line of an inner periphery of said central portion. The leg portions also have outer peripheries having center lines being parallel to each other and have thicknesses, different in circumferential directions thereof, at cross sections in directions normal to center lines of the outer peripheries of the respective leg portions.

Abstract: A linear motion apparatus has a guide shaft including a spiral-shaped or linear-shaped rolling element rolling groove, a movable body including a spiral-shaped or linear-shaped rolling element rolling groove opposed to the rolling element rolling groove of the guide shaft, a large number of rolling elements rollably moving along a rolling element rolling passage formed between the rolling element rolling grooves of the guide shaft and movable body and, a rolling element return passage communicating with the rolling element rolling passage, wherein, in the portion of the rolling element rolling groove of the movable body that is adjacent to an open end of a rolling element return passage, an escape portion is formed by abrasive flow machining in such a manner that the grinding depth thereof increases gradually toward the open end of the rolling element return passage.

Abstract: In a ball screw drive comprising a spindle (1), a nut (3) surrounding the spindle (1), and balls (4) arranged between the spindle (1) and the nut (3), which balls (4) are in rolling contact with a screw track (2) formed on the spindle (1) and on corresponding screw tracks (7, 12) formed on rings arranged within the nut (3) comprises a deflecting region for returning the balls (4) from a run-out end of a common turn of the screw tracks (2, 7, 12) to a run-in end of this turn, the screw tracks (7, 12) of the rings arranged in the nut (3, 15) are made on front faces of these rings with the screw tracks (7, 12) of two adjacent rings defining together with the screw track (2) of the spindle (1, 18), an endless circulation channel for the balls (4).

Abstract: A ball screw which is little subject to deterioration of operating characteristics and occurrence of wear, torque change, noise, vibration, etc. during operation due to stagnation or competition of balls. The ball screw includes a screw shaft having a helical thread groove formed on the outer surface thereof and a nut having a thread groove formed on the inner surface thereof corresponding to the thread groove on the screw shaft which engages with the screw shaft with the interposition of a number of balls rollably provided in a helical ball rolling path formed between the two thread grooves, and spacers between adjacent ones of the number of balls, wherein the variation of the total of the gap between the balls and spacers during the rolling of the balls is smaller than 1/20 of the diameter of the ball.

Abstract: A linear-motion device has: a linear-motion element fitted on a shaft which moves straight along the shaft; a plurality of balls which are retained in a ball groove formed on the inner side of the linear-motion element and roll over between the ball groove and the shaft; a separator interposed between the balls; and, a circulating path formed in the linear-motion element through which the balls are circulated from one end of the ball groove to the other, which is filled with a grease, wherein the separator is a formed product comprising as a resin component a polybutylene naphthalate-based elastomer formed by a hard segment made of a polybutylene naphthalate and a soft segment made of a polycondensate of 2,6-naphthalanedicarboxylic acid with a polytetramethylene ether glycol.

Abstract: The ball screw apparatus of an end cap type comprises a ball nut which includes a nut main body having a ball circulation hole penetrating through the nut main body in the axial direction thereof and two end caps respectively fixed to the two end portions of the nut main body and defining two ball circulation R portions between the end faces of the nut main body and themselves. A guide groove for a ball is defined only on the end face side of the nut main body to thereby define the ball circulation R portion, and the shapes of the surfaces of the end cap, which are disposed opposed to the end faces of the nut main body, are defined substantially uniform over the entire peripheries thereof.

Abstract: A ball screw apparatus, has a screw shaft including a screw groove; a nut fitted with the screw shaft, the nut including a screw groove and a ball return passage; a circulation piece including a ball circulation passage; and, a large number of balls, wherein, in the inner peripheral surface of the nut, a concave-shaped snap ring groove extending along the peripheral direction of the nut is formed, in the face of the circulation piece that faces the inside diameter side of the nut, a concave-shaped snap ring groove is formed so as to connect to the snap ring groove of the nut, and an outside diameter portion of a snap ring is fitted into the two snap ring grooves to thereby fix the circulation piece to the nut.

Abstract: A ball screw comprises a screw shaft, a nut assembled with the screw shaft, a number of balls disposed in the ball rolling passage formed by a ball rolling groove formed to the screw shaft and a loaded ball rolling groove formed to the nut, a number of spacers disposed between the balls in the ball rolling passage, and a circulation member for circulating the balls and spacers in accordance with a relative motion of the nut with respect to the screw shaft. The circulation member is provided with a scoop-up groove for scooping the balls, when contacting the ball rolling in the ball rolling passage, at both side edge portions of the scoop-up groove and is also provided with a spacer scoop-up portion which contacts and scoops the spacer moving in the ball rolling passage without contacting the balls. Such circulation member will be preferably utilized for a motion guide device such as linear motion guide or spline shaft.

Abstract: A coupled circulation tube for a ball screw unit. The tube is formed on a planar surface at one side of the ball screw bearing, each tube joined to two circulation holes. Each circulation tube is formed by coupling two symmetrical rigid metallic half tubes at recessed grooves and flanges interposedly arrayed one after another longitudinally along the wall of each half tube to form a resultant U shaped arcuate elbow tube for ball circulation such that it is firmly constructed with a desired toughness free from loosening, cracking or deforming by constant collision and abrasion of the rolling balls.

Abstract: In the ball screw, a ball circulation tube 20 is formed to have such a shape that the movable amount of balls 15 in a first direction (X) intersecting at right angles to the axis of the tube 20 is larger than the movable amount of the balls 15 in a second direction (Y) intersecting at right angles to the first direction (X), and the ball circulation tube 20 is fixed to a nut 13 in such a manner that the outer surface 20a of the tube 20 extending in parallel with the first direction (X) is opposed to the outer surface of the nut 13.

Abstract: A ball-nut assembly includes a ball nut and a crossover member. The ball nut incudes a radial through slot and an outer surface. The outer surface has a first portion, has a ledge radially recessed from the first portion and at least partially bounding the through slot, and has an undercut wall connecting the ledge and the first portion. The crossover member has a flange and a crossover-grooved portion. A method for making a ball-nut assembly positions the crossover member from outside the ball nut to have the flange supported by the ledge and the crossover-grooved portion located in the through slot. The method also deforms the flange creating a staked portion of the flange which contacts the undercut wall of the outer surface of the ball nut.

Abstract: A ball nut and return liner assembly includes a ball nut having a tubular body having a longitudinal axis, the tubular body having an inner surface and an outer surface, a plurality of arcuate grooves defined on the inner surface. A longitudinal slot is defined on the inner surface parallel to the longitudinal axis, interrupting the plurality of arcuate grooves, and forming a pocket for receiving the return liner, the longitudinal slot having first curved walls. The return liner is provided with a first surface having a plurality of S-shaped return grooves extending from the first side to the second side to cooperate with the plurality of arcuate grooves in the ball nut. The return liner is further provided with a second surface for fitting within the longitudinal slot within the ball nut, the second surface having second curved walls.

Abstract: In the ball screw, a ball circulation tube 20 is formed to have such a shape that the movable amount of balls 15 in a first direction (X) intersecting at right angles to the axis of the tube 20 is larger than the movable amount of the balls 15 in a second direction (Y) intersecting at right angles to the first direction (X), and the ball circulation tube 20 is fixed to a nut 13 in such a manner that the outer surface 20a of the tube 20 extending in parallel with the first direction (X) is opposed to the outer surface of the nut 13. Accordingly, it is possible to provide a ball screw which can restrict variations in the torque of the ball screw caused by the mutual sliding movements of balls occurring within a ball circulation tube.

Abstract: The invention concerns a ball screw-nut device comprising a screw (2) and a nut (3), the nut including a housing (7) and a ball-bearing element (4) comprising a raceway (13) and a plurality of balls (15), the ball-bearing element (4) being produced as an independent part which assembled with the housing.

Abstract: A ball screw apparatus has: a screw shaft including a screw groove; a nut movably fitted with the screw shaft and including a screw groove; a large number of balls rollably disposed in a loaded raceway; and a side cap mounted on the outer peripheral portion of the nut and including a ball circulation passage for scooping up the balls rolling along the loaded raceway in a direction coincident with the lead angle of the two screw grooves and returning the balls to the loaded raceway, wherein, the two screw grooves are respectively formed as multiple thread screws and the side cap is disposed on each of the multiple threads.

Abstract: An internal recirculating ball screw and nut system that is easier to manufacture and more reliant by virtue of a particular configuration of the grooves on the interior of the nut or the follower. Crossback portions of select nut grooves are arranged in a manner that allows the bearing balls to recirculate by slipping over the top of adjacent thread lands of the screw, advancing and recirculating within a single 360 degree rotation within said nut. Said recirculation is accomplished solely through the design of the path of a unitary nut, without use of any ancillary devices.

Abstract: Between two mutually adjoining load balls 5, there is interposed a retaining piece 10 having two concave surfaces 11 which are respectively opposed to the two adjoining load balls 5. The retaining piece 10 has an outside diameter dimension equal to or more than 0.5 times the outside diameter dimension of the load ball 5. Further, the retaining piece 10 has an outside diameter dimension which, when the retaining piece 10 passes through a screw groove circulation passage and a tube circulation passage, prevents the retaining piece 10 from touching the inner walls of these screw groove circulation passage and tube circulation passage, or has an outside diameter dimension which is equal to or less than 0.9 times the outside diameter dimension of the load ball.

Abstract: A ball screw assembly includes a ball nut or a ball screw having internal or external, respectively, helical curves, wherein two adjacent turns of the helical curves are joined by a crossover/crossunder path, wherein ends of the crossover/crossunder path and ends of the helical curves are integrally joined without interruption. A ball screw assembly may further include crossover/crossunder paths which are staggered about the screw or the nut.

Abstract: Ball screw nut is composed of an inner threaded nipple and an outer housing. The nipple is constructed with a hollow hard tubular metallic material to ensure the strength of the structure; while the outer housing where requires less strength is formed of a plastic material by ejection mold process so as to reduce the production cost and simplify the fabrication process. The nipple and the housing are conjoined together by screw engagement.

Abstract: A ball screw which is little subject to deterioration of operating characteristics and occurrence of wear, torque change, noise, vibration, etc. during operation due to stagnation or competition of balls. The ball screw includes a screw shaft having a helical thread groove formed on the outer surface thereof and a nut having a thread groove formed on the inner surface thereof corresponding to the thread groove on the screw shaft which engages with the screw shaft with the interposition of a number of balls rollably provided in a helical ball rolling path formed between the two thread grooves, wherein the variation of the total of the gap between the balls during the rolling of the balls is smaller than {fraction (1/20)} of the diameter of the ball.

Abstract: There is provided a return pipe type ball screw capable of accurately positioning and fixing return pipes on and to a nut member even when a troublesome positioning operation is not carried out, and circulating balls endlessly and smoothly for a long period of time without the possibility that dust enters the interior of the nut member. In such a ball screw, ball passing holes formed so as to extend through the nut member are inclined at an angle equal to a lead angle of a ball rolling groove of a screw shaft, and each of the return pipes is formed by combining together a pair of return pieces adapted to be fitted in the ball passing holes.

Abstract: An internal recirculating ball screw and nut system that is easier to manufacture and more reliant by virtue of a particular configuration of the grooves on the interior of the nut or the follower. Crossback portions of select nut grooves are arranged in a manner that allows the bearing balls to recirculate by slipping over the top of adjacent thread lands of the screw, advancing and recirculating within a single 360 degree rotation within said nut. Said recirculation is accomplished solely through the design of the path of a unitary nut, without use of any ancillary devices.

Abstract: A ball screw comprises a screw shaft, a nut assembled with the screw shaft, a number of balls disposed in the ball rolling passage formed by a ball rolling groove formed to the screw shaft and a loaded ball rolling groove formed to the nut, a number of spacers disposed between the balls in the ball rolling passage, and a circulation member for circulating the balls and spacers in accordance with a relative motion of the nut with respect to the screw shaft. The circulation member is provided with a scoop-up groove for scooping the balls, when contacting the ball rolling in the ball rolling passage, at both side edge portions of the scoop-up groove and is also provided with a spacer scoop-up portion which contacts and scoops the spacer moving in the ball rolling passage without contacting the balls. Such circulation member will be preferably utilized for a motion guide device such as linear motion guide or spline shaft.

Abstract: A ball nut and return liner assembly includes a ball nut having a tubular body having a longitudinal axis, the tubular body having an inner surface and an outer surface, a plurality of arcuate grooves defined on the inner surface. A longitudinal slot is defined on the inner surface parallel to the longitudinal axis, interrupting the plurality of arcuate grooves, and forming a pocket for receiving the return liner, the longitudinal slot having first curved walls. The return liner is provided with a first surface having a plurality of S-shaped return grooves extending from the first side to the second side to cooperate with the plurality of arcuate grooves in the ball nut. The return liner is further provided with a second surface for fitting within the longitudinal slot within the ball nut, the second surface having second curved walls.

Abstract: The invention provides a ball screw which is little subject to deterioration of operating characteristics and occurrence of wear, torque change, noise, vibration, etc. during operation due to stagnation or competition of balls. A ball screw comprising a screw shaft having a helical thread groove formed on the outer surface thereof and a nut having a thread groove formed on the inner surface thereof corresponding to the thread groove on the screw shaft which engages with the screw shaft with the interposition of a number of balls rollably provided in a helical ball rolling path formed between the two thread grooves, wherein the variation of the total of the gap between said balls during the rolling of the balls is smaller than {fraction (1/20)} of the diameter of the ball.

Abstract: A ball screw has a screw shaft including a spiral-shaped ball rolling groove formed in an outer peripheral surface thereof; a nut including a spiral-shaped ball rolling groove formed in an inner peripheral surface thereof; a plurality of balls disposed in a raceway formed by the two rolling grooves; and, a return path for moving the balls from the terminal point of the raceway to the start point of the raceway, the two end portions of the return path respectively including a rising surface rising from the ball rolling groove of the nut and a stopper portion disposed opposed to the rising surface to form the end portion of the raceway, wherein a boundary portion between the rising surface and the ball rolling groove of the nut is formed a round portion having the radius of curvature 0.05 times the diameter of the ball or more.

Abstract: A ball screw mechanism includes a ball screw shaft of a metal material coaxially connected to a rotary driving source, a nut member of a resin material being screwed onto the ball screw shaft, a plate member fixed to an upper surface of the nut member by screw members, and steel balls which are arranged on a passage formed in the nut member closed by the plate member and which are installed into screw grooves of the ball screw shaft and the nut member.

Abstract: A ball screw has a screw shaft including a ball thread groove formed on an outer peripheral surface thereof, a nut including a ball thread groove formed on an inner peripheral surface thereof, the inner peripheral surface being opposed to the outer peripheral surface of the screw shaft, and a side cap mount surface being formed in the outer peripheral surface of the nut, a plurality of balls disposed between the thread groove of the nut and the thread groove of the screw shaft; and, a side cap fastened to the side cap mount surface and including a ball scooping part and a ball return path for scooping up the balls from one side and returning the balls to another side.

Abstract: A screw device having a lubricant applying structure comprises a screw shaft provided with a spiral ball rolling groove, a nut provided with a loaded ball rolling groove having a spiral shape corresponding to the spiral ball rolling groove formed to the screw shaft, a number of balls disposed in a loaded rolling passage formed by the ball rolling groove and the loaded ball groove, a return member provided for the nut and arranged so as to connect one and another end portions of the loaded rolling passage so that the balls rolling the loaded rolling passage circulate, and a lubricant applying portion mounted to the return member so as to apply a lubricant. The lubricant applying portion is arranged inside the return member provided for the nut.

Abstract: The ball scooping position of a ball is setted downwardly of a reference line and the angle of the ball scooping position with respect to the reference line is setted at an angle of −15°. The end face of the rising portion of a tube is disposed so as to coincide with the reference line. The axis of the rising portion is setted so as to be present outside of a line corresponding to the ball center locus of a raceway. The inner surface of the pickup portion of the tube is connected with the ball scooping position of the ball rolling groove of a nut by a surface which exists outside of the ball rolling groove of the nut.

Abstract: In the ball screw, a ball circulation tube 20 is formed to have such a shape that the movable amount of balls 15 in a first direction (X) intersecting at right angles to the axis of the tube 20 is larger than the movable amount of the balls 15 in a second direction (Y) intersecting at right angles to the first direction (X), and the ball circulation tube 20 is fixed to a nut 13 in such a manner that the outer surface 20a of the tube 20 extending in parallel with the first direction (X) is opposed to the outer surface of the nut 13. Accordingly, it is possible to provide a ball screw which can restrict variations in the torque of the ball screw caused by the mutual sliding movements of balls occurring within a ball circulation tube.

Abstract: The ball scooping position of a ball is setted downwardly of a reference line and the angle of the ball scooping position with respect to the reference line is setted at an angle of −15°. The end face of the rising portion of a tube is disposed so as to coincide with the reference line. The axis of the rising portion is setted so as to be present outside of a line corresponding to the ball center locus of a raceway. The inner surface of the pickup portion of the tube is connected with the ball scooping position of the ball rolling groove of a nut by a surface which exists outside of the ball rolling groove of the nut.