Abstract: A linear motion rolling contact guide unit includes a rail having a horizontally extending wing section, a slider slidably mounted on the rail and a plurality of rollers interposed between the top surface of the rail and the slider so as to allow a shift in position in a lateral direction between the rail and the slider as the slider moves along the rail. A first slide member is fixedly attached to the slider to define a first squeeze film damper between the top surface of the rail and the first slide member. A second slide member is fixedly attached to the slider to define a second squeeze film damper between the bottom surface of the wing section and the second slide member. Each of the first and second squeeze film dampers includes an oil film for damping or absorbing any undesired vibratory motion.

Abstract: A linear motion rolling contact guide unit includes a rail, a slider assembly and a plurality of rolling members interposed between the rail and the slider assembly. The slider assembly includes a pair of lower and upper sub-assemblies. The lower sub-assembly is slidably mounted on the rail and the upper sub-assembly is mounted on the lower sub-assembly such that it may move transversely relative to the lower sub-assembly over a limited distance. A low friction intermediate member is provided at a first location in a gap between the opposed surfaces of the upper and lower sub-assemblies so as to provide an enhanced sliding characteristic therebetween. A squeeze film damper mechanism is provided at a second location in the gap between the upper and lower sub-assemblies for damping and/or absorbing undesired motion.

Abstract: A linear motion rolling contact guide unit includes a rail, a slider assembly and a plurality of rolling members interposed between the rail and the slider assembly so that the slider assembly can move along the rail in any direction. The slider assembly has a two-part structure and is comprised of a pair of first and second sub-assemblies with a low friction intermediate structure interposed therebetween. The first sub-assembly is slidably mounted on the rail and the second sub-assembly is mounted on the first sub-assembly such that the second sub-assembly can move relative to the first sub-assembly in the direction transverse to the longitudinal axis of the rail. Thus, when the present unit is applied to a guide unit of a heavy duty linear motion guide unit system, any error in lateral alignment can be absorbed by the present unit.

Abstract: A double rail linear motion guide assembly suitable for carrying a load large in weight and size is provided. A pair of main and auxiliary guide rails are fixedly attached to a base. An inner guide groove is formed at each of the side surfaces of the main guide rail having a rectangular cross section. A U-shaped main slider provided with a pair of endless circulating paths is fixedly attached to a table and slidably mounted on the main guide rail in a straddling fashion and formed with an outer guide groove at its inner side surface. A plurality of rolling members are provided in the endless circulating paths. The auxiliary guide rail has a flat top guide surface and at least one flat bottom guide surface. An auxiliary slider having either a generally C-shaped or L-shaped cross section is fixedly attached to the table and slidably mounted on the auxiliary guide rail and is formed with endless circulating paths filled with rolling members.

Abstract: A sliding contact type linear motion guide unit having at least one of desired anti-vibration and braking functions is provided. The unit includes a rail extending over a desired length, a slider movably mounted on the rail and a sliding member interposed between the rail and the slider. The sliding member includes an elastic member fixedly attached to the slider and a contact member fixedly attached to the elastic member and having a contact surface in sliding contact with the rail. In the preferred embodiment, the elastic member includes an elastic enclosure having therein a fill, such as a gas, liquid or gel, under pressure, so that the contact pressure between the contact member and the rail can be maintained substantially unchanged and uniformly. A control valve is preferably provided in communication with the interior of the enclosure.

Abstract: A ball screw assembly includes a screw shaft hving a peripheral surface formed with a spiral groove, an outer sleeve fitted onto the screw shaft with a predetermined gap therebetween and a plurality of balls interposed between the screw shaft and the outer sleeve. A ball holder is provided in a radial hole formed in the outer sleeve and a ball is rotatably held in position and in engagement with the spiral groove by the ball holder. A fluid line is formed in the outer sleeve and the ball holder so that a pressuerized fluid may be supplied to establish a fluidic cushion between the ball holder and the ball. Also provided is a plurality of solid lubricants which are preferably arranged alternately with the balls and normally pressed against the spiral groove to keep the groove lubricated at all times.

Abstract: A ball spline bearing assembly includes a spline shaft having a peripheral surface formed with a spline groove, an outer sleeve fitted onto the spline shaft with a predetermined gap therebetween and a plurality of balls interposed between the spline shaft and the outer sleeve. A ball holder is provided in a radial hole formed in the outer sleeve and a ball is rotatably held in position and in engagement with the spline groove by the ball holder. A fluid line is formed in the outer sleeve and the ball holder so that a pressurized fluid may be supplied to establish a fluidic cushion between the ball holder and the ball. Also provided is a plurality of solid lubricants which are normaly pressed against the spiral groove to keep the groove lubricated at all times.

Abstract: A sliding contact type linear motion guide unit having at least one of desired anti-vibration and braking functions is provided. The unit includes a rail extending over a desired length, a slider movably mounted on the rail and a sliding member interposed between the rail and the slider. The sliding member includes an elastic solid member fixedly attached to the slider and a contact member fixedly attached to the elastic solid member and having a contact surface in sliding contact with the rail. In the preferred embodiment, the elastic solid member is constructed by a corrugated spring, rubber, a synthetic resin or the like so that the contact pressure between the contact member and the rail can be maintained substantially unchanged and uniformly.

Abstract: A linear motion rolling contact guide unit includes a guide rail, a slider and a plurality of rolling members interposed between the guide rail and the slider. The guide rail is formed with a pair of upper inner guide grooves and a pair of lower inner guide grooves and the slider is formed with a pair of upper outer guide grooves and a pair of lower outer guide grooves correspondingly. The guide grooves are arranged such that two contact points between a rolling member and an associated upper pair of inner and outer guide grooves and two contact points between a rolling member and an associated lower pair of inner and outer guide grooves define a straight line. Preferably, the center of each of the rolling members also lies on the straight line.

Abstract: A splined ball screw assembly having a nested structure is provided. A hollow shaft extends into an outer sleeve and a center shaft extends into the hollow portion of the hollow shaft. A ball screw structure is provided at either side of the outer and inner peripheral surfaces of the hollow shaft and a ball spline structure is provided on the other side. The outer sleeve is rotatably mounted on a housing and the center shaft is also rotatably mounted on the housing. By controlling the amount and direction of rotation of both of the outer sleeve and the center shaft, the hollow shaft may be moved longitudinally in a desired direction and/or set in rotation. The present assembly is compact in size and particularly suitable for use in a robot arm.

Abstract: There is provided a linear motion rolling guide unit mainly comprising a square pillar-shaped long track rail having rail side track grooves formed in the longitudinal direction on both side surfaces of the rail, and a casing having an inverse U-shaped cross section mounted over the rail through a concave portion with a plurality of rolling members being intervened therebetween. Endless circulating passages for rolling members are provided within the casing or within an assembly of the casing and a pair of side plates, in a symmetrical relation at an angle .alpha., as seen in the cross section of the casing, relative to the longitudinally and centrally extending vertical plane of the track rail.

Abstract: A multi-mode splined ball screw assembly includes a first shaft, a hollow second shaft and a hollow third shaft. The first shaft extends into the hollow second shaft and a ball spline structure is provided between the first and second shafts so that they may move relative to each other in the longitudinal direction. The second shaft extends into the third shaft and a ball screw structure is provided between the second and third shafts so that they may rotate relative to each other. The first shaft is rotatably supported by a housing and the third shaft has an outer peripheral surface, a part of which is defined as a ball spline surface section and another part of which is defined as a ball screw surface section. Another ball spline structure is provided between the housing and the ball spline surface section and another ball screw structure is provided between the housing and the ball screw surface section.

Abstract: A magnetic fluid bearing may include a sleeve provided with a through bore, a shaft inserted into the bore, electromagnets engaged with the bore of the sleeve with a gap provided between the shaft and the electromagnets, a magnetic fluid introduced into the gap between the electromagnets and the shaft, and a controller for modifying the magnetic force of the electromagnets in accordance with changes in a load condition of the bearing. One or more electromagnets for radial loads may be engaged with the sides of the bore and an electromagnet for thrust loads may be engaged with a bottom of the bore. The controller has a sensor to detect changes in an inductance or capacitance that are indicative of the position of the shaft. The controller translates the changes into signals and transmits the signals to a power amplifier to modify the position of the shaft by changing the rate of electric current running through the electromagnets.

Abstract: There is provided a rectilinear motion rolling guide unit comprising: a long track rail having an almost I-shaped cross section; a casing having an almost inverse U-shaped cross section; and rolling elements interposed between the track rail and the casing. The casing is arranged so as to ride over the track rail by a concave portion formed in the central lower portion of the casing. Upper and lower corner portions of both upper projecting portions of the track rail are chamfered to form inclined surfaces, thereby forming two upper and lower rail side track surfaces, respectively. Two upper and lower casing side track surfaces are formed on the inner peripheral surfaces of the concave portion of the casing at positions corresponding to the two upper and lower rail side track surfaces. A number of rolling elements are interposed between the corresponding track surfaces on the rail and casing sides, respectively, thereby allowing a relative slidable motion between the track rail and the casing.

Abstract: There is provided a linear motion rolling guide unit mainly comprising a square pillar-shaped long track rail having rail side track grooves formed in the longitudinal direction on both side surfaces of the rail, a casing having an inverse U-shaped cross section mounted over the rail through a concave portion, a pair of side plates fixedly joined to both longitudinally end surfaces of the casing, and rolling ball return passages formed in parallel in correspondence to the casing side track grooves. An endless circulating passage for rolling elements is formed by coupling at the extreme ends, the casing side track grooves and the return passages extending in parallel thereto by opposingly arranged arc-shaped direction turning passages. The track rail, casing, and side plates are made of high performance engineering plastics. Cylindrical projections and/or arcuate bridge-shaped U-turn tracks are formed on both longitudinally end wall surfaces of the casing.

Abstract: A rectilinear motion rolling guide unit comprises: a long track rail having an I-shaped cross section; a casing having an inverse U-shaped cross section; and rolling elements interposed between the track rail and the casing. The casing rides over the track rail through a cavity portion having an inverse U-shaped cross section formed in the central lower portion of the casing. The corners of the upper and lower projecting portions on both sides of the rail are chamfered into inclined surfaces, thereby forming two upper and lower rail side track surfaces. Two upper and lower casing side track surfaces are formed on the inner peripheral surfaces of the cavity portion at the positions corresponding to the rail side track surfaces. The rolling elements are interposed between the opposite rail side and casing side track surfaces, respectively, thereby allowing the relative free slide motion to be executed between the track rail and the casing. Return passageways are formed in the casing.

Abstract: There is provided a sheet-metal type endless rectilinear motion rolling guide unit comprising U-shaped bed and table which are arranged so that their opening portions face each other. A first track groove is formed in each outside wall of the bed in the longitudinal direction. A second track groove is formed in each inside wall of the table in the longitudinal direction. Balls are inserted between these track grooves, thereby relatively rectilinearly moving the bed and table. A third tract groove is formed in each outside wall of the table at the position corresponding to the second track groove. A U-shaped return passage side plate forming a return passage of the balls is attached to each outside wall of the table in parallel with the second track groove. An end cap formed with a direction turning passage to couple the second track groove with the return passage is attached to each end of the track groove portion in the slide direction of the table.

Abstract: A fluid bearing assembly includes a first element and a second element which moves relative to the first element along a predetermined path. The first element has a first surface which is opposite to a second surface of the second element. A recess is defined at least in either one of the first or second surfaces for maintaining therein a quantity of fluid, such as air and liquid. Also provided is a heater inside of the recess so that the fluid inside of the recess is heated to expand in volume, thereby pressurizing the fluid to establish alignment between the first and second elements. Such a fluid bearing assembly may be applied not only for the rotary type bearing assembly, but also for the linear motion type bearing assembly.