Nsk Corporation

Shinichi Kasuga

Hiroki Yamaguchi

Ryoichi Sato

Soichiro Kato

Nobuaki Fujimura

Kenji Kano

Nobumitsu Takahashi

In a linear guide bearing apparatus wherein a separator is interposed between adjacent balls K and K moving following a curved circulating path, and the ball K contacts concave faces W of the separator Tat both ends in an axial line direction and at the same time the ball K rolls as contacting a guide faceof an outside guiding memberand a guide faceof an inside guiding member, the separator has an outer diameter larger than a maximum outer diameter L&#xd8; under a condition where the ball rolls as simultaneously contacting both curved facesof the inside and the outside of the curved circulating path, and the radius of curvature of the guiding facein the curved circulating pathis reduced to a size not contacting the separator T.

Linear guide bearing apparatus

In a linear guide bearing apparatus wherein a separator is interposed between adjacent balls K and K moving following a curved circulating path, and the ball K contacts concave faces W of the separator T at both ends in an axial line direction and at the same time the ball K rolls as contacting a guide faceof an outside guiding memberand a guide faceof an inside guiding member, the separator has an outer diameter larger than a maximum outer diameter L&#x3c6; under a condition where the ball rolls as simultaneously contacting both curved facesof the inside and the outside of the curved circulating path, and the radius of curvature of the guiding facein the curved circulating pathis reduced to a size not contacting the separator T.

Disclosed is a linear guide device in which a rate of change expressed as 'Dmax&#x2212;Dmin', becomes extremely small where Dmax and Dmin are respectively a local maximum and a local minimum of D, expressed as (dxdx)/dx, which is produced when a steel ball B moves a distance corresponding to a rolling element-to-rolling element span, dxis a minute movement quantity of a steel ball B when it moves from one space defined between rolling element rolling groovesandof an element endless circulating racewayto one of curved element circulating R partsand dxis a minute movement quantity of another steel ball B when it moves from the other curved element circulating R partto the space while the former steel ball is moved by the minute movement quantity dx

Linear guide device

In a retaining piece interposed between the adjacent rolling balls, a concave surface of each of both side surfaces of the retaining piece where it contacts with the spherical surfaces of the balls is configured to partly contact with the spherical surface of the ball. The concave surface includes a linear contact portion to be in contact with the ball and an approximate curved surface having the radius of curvature approximate to that of the ball, which is located on the inner side of the linear contact portion. In addition, recesses which are joined to the gate portion and the ejector pin in a molding process are formed in the concave surfaces. A recess is formed at the joining portion or near a parting line. Fins formed in the molding process are capable to be put into the recess.

Retaining piece structure

In the present linear guide bearing, the center of curvature O&prime; of a ball reversing passage is shifted to a return side ball passage side by a given amount m when compared with the center of curvature O&prime; of a conventional guide bearing. Due to this, not only the radius of curvature of a concave-arc-shaped groove formed in each end cap is reduced by a given amount m but also the concave-arc-shaped groove is shifted to the return side ball passage side by a given amount m, when compared with the conventional guide bearing. Thus, an angle &agr; formed between a line connecting the leading end of a tongue portion to the center of curvature O&prime; of a ball reversing passage and the moving-direction end face of a bearing main body can be reduced significantly when compared with the conventional bearing.

Linear guide bearing

In a linear guide bearing apparatus wherein a separator is interposed between adjacent balls K and K moving following a curved circulating path , and the ball K contacts concave faces W of the separator T at both ends in an axial line direction and at the same time the ball K rolls as contacting a guide face of an outside guiding member and a guide face of an inside guiding member , the separator has an outer diameter larger than a maximum outer diameter L&phgr; under a condition where the ball rolls as simultaneously contacting both curved faces of the inside and the outside of the curved circulating path , and the radius of curvature of the guiding face in the curved circulating path is reduced to a size not contacting the separator T.

A linear guide device in which a rate of change expressed as &ldquo;Dmax&minus;Dmin&rdquo;, becomes extremely small where Dmax and Dmin are respectively a local maximum and a local minimum of D, expressed as (dx2&minus;dx1)/dx, which is produced when a steel ball B moves a distance corresponding to a rolling element-to-rolling element span, dx1 is a minute movement quantity of a steel ball B when it moves from one space defined between rolling element rolling grooves and of an element endless circulating raceway to one of curved element circulating R parts and dx2 is a minute movement quantity of another steel ball B when it moves from the other curved element circulating R part to the space while the former steel ball is moved by the minute movement quantity dx1.

In the present linear guide bearing, the center of curvature O&prime; of a ball reversing passage is shifted to a return side ball passage side by a given amount m when compared with the center of curvature, O&prime; of a conventional guide bearing. Due to this, not only the radius of curvature of a concave-arc-shaped groove formed in each end cap is reduced by a given amount m but also the concave-arc-shaped groove is shifted to the return side ball passage side by a given amount m, when compared with the conventional guide bearing. Thus, an angle &agr; formed between a line connecting the leading end of a tongue portion to the center of curvature O&prime; of a ball reversing passage and the moving-direction end face of a bearing main body , can be reduced significantly when compared with the conventional bearing.

A ball screw integrated linear guide unit arranging on an inner end surface of an end cap not only linear guide ball lubricating grease feed passages reaching the curved passages from the grease nipple and a ball screw ball lubricating grease feed passage reaching the ball screw spiral groove from the grease nipple, whereby simultaneous lubrication for linear guide feed line and ball screw feed line can be achieved.

Ball screw integrated linear guide unit

In order to offer a linear working unit which is a linear working unit capable of accurately driving two movable members in mutually reverse directions, i.e., leftward and rightward, with a single driving means and yet formed in a construction highly accurate in performance but compact and moderately priced, according to the present invention, a left-hand thread part and a right-hand thread part are formed on a single feed screw, with a nut block being joined independently with each of the left-hand thread part and the right-hand thread part and with the respective nut blocks being installed on a guide rail, and rolling elements are set in the space between the rolling groove formed for the rolling elements in the guide rail and the rolling grooves formed in the nut blocks, so that the nut blocks are kept free to slide in the axial direction by the effect of the rolling motion of these rolling elements. Thereby, the linear working unit is capable of operating the two nut blocks so as to make their highly accurate movements in the mutually reverse directions, i.e., leftward and rightward, through control of a single feed screw and, as these nut blocks are built into the same guide rail, the linear working unit can offer the additional advantage that it can be formed in a non-bulky structure comprised of a smaller number of items of component parts and can yet be operated in a simple manner.

Linear working unit

There is disclosed a ball screw integrated type linear movement guiding unit which achieves a stable, smooth operability, and can meet with a high-load and high-rigidity application. Each of ball return passageways which respectively provide ball-circulating passageways of a ball screw system and a linear movement guiding system in the unit is constituted by an axial through hole much larger in diameter than a ball, and a cylindrical member of a synthetic resin which has an inner diameter generally equal to the diameter of the ball and is press-fitted in the through hole. With this construction, the rolling of the balls is effected smoothly. Further, even if the length of a nut is increased to meet with a high-load and high-rigidity use, the ball return passageway can be easily formed.

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Gunma, Japan

Shinichi Kasuga