Linear ball bearing guideway

摘要

A linear ball bearing guideway is provided with six rows of balls disposed between the slider and the rail, so as to improve the overall load capacity. The six rows of balls are symmetrically disposed at two sides of the head portion of the rail, and the three of the six rows of balls at each side are located at different heights. The neck-portion width of the head portion is smaller than a distance between the two rows of balls disposed at the lowest rail rolling grooves, but larger than the value of a distance between the two rows of balls in the highest rail rolling grooves minus a diameter of the balls, which ensures that the neck-portion width is overly small and affect the stiffness of the rail.

主权项

1. A linear ball bearing guideway comprising:
a rail being an elongated structure extending along a direction X, two directions perpendicular to the direction X being defined as a direction Y and a direction Z which is perpendicular to the direction Y, a cross section of the rail in the direction X being a symmetrical structure with respect to a symmetrical axis, the rail including a head portion, a neck portion and a bottom portion which are sequentially arranged in the direction Z, the head portion being located at an upper position along the direction Z, a direction of the head portion along the Z direction being defined as an upper direction which extends from a bottom of the head portion to a top of the head portion, and a direction of the bottom portion along the direction Z being defined as a lower direction which extends from a top of the bottom portion to a bottom of the bottom portion, the head portion having a first maximum width in the direction Y defined as a head-portion width, the neck portion having a minimum width in the direction Y defined as a neck-portion width, the bottom portion including a second maximum width in the direction Y defined as a bottom-portion width, and the neck-portion width being smaller than the head-portion width and the bottom-portion width, both sides of the rail with respect to the symmetrical axis being symmetrically provided with three rail rolling grooves; a slider slidably sleeved onto the rail, the slider being provided with six slider rolling grooves which are aligned with the rail rolling grooves; a plurality of balls rotatably disposed between the slider rolling grooves and the rail rolling grooves; the linear ball bearing guideway being characterized in that: the three rail rolling grooves are an upper rail rolling groove, a middle rail rolling groove and a lower rail rolling groove which are formed at both sides of the head portion of the rail with respect to the symmetrical axis, the upper rail rolling groove is located higher than the middle rail rolling groove in the direction Z, and the middle rail rolling groove is located higher than the lower rail rolling groove in the direction Z; there are contact points between the balls and each of the upper, middle and lower rail rolling grooves, and each of the contact points is provided with a normal line, each of the normal lines of the upper and middle rail rolling grooves defines a contact angle of 20-70 degrees with respect to the upper direction of the direction Z, the normal line in the lower rail rolling grooves defines a contact angle of 20-70 degrees with respect to the lower direction of the direction Z; a distance between centers of the balls received in the two upper rail rolling grooves along the direction Y is defined as a first ball-center distance, a distance between centers of the balls received in the two middle rail rolling grooves along the direction Y is defined as a second ball-center distance, and the neck-portion width is greater than the value of the first ball-center distance minus the diameter of the balls.