Curvilinear motion guide units

A curvilinear motion guide unit comprising a track rail extending curved with a preselected curvature and having lengthwise side surfaces made thereon with first raceway grooves, and a slider fitting astride over the track rail for movement in a sliding manner along the track rail;

• wherein the slider is comprised of a casing provided with second raceway grooves and return passages formed corresponding to the second raceway grooves, end caps mounted on forward and aft end faces of the casing, each to each end face, and provided therein with turnarounds connecting the second raceway grooves to the return passages, rolling elements running through recirculating passages composed of curved raceways defined between the first and second raceway grooves, the turnarounds and the return passages, and end seals attached on the end caps, each to each cap;
• wherein the forward and aft end faces of the casing are each arranged such that an imaginary plane including any one of the end faces and normal to a top surface of the track rail coincides with a radial plane extending through the center of curvature of the track rail, and the return passages are opened on the forward and aft end faces at locations that are closer to a centroidal axis of the track rail than locations where the raceways are made open of the forward and aft end faces, and
• wherein the return passages made in the casing are linear bores that run straight through the casing from any one of the forward and aft end faces to the other.

A curvilinear motion guide unit comprising a track rail extending curved with a preselected curvature and having lengthwise side surfaces made thereon with first raceway grooves, and a slider fitting astride over the track rail for movement in a sliding manner along the track rail;

• wherein the slider is comprised of a casing provided with second raceway grooves extending curved in conformity with the first raceway grooves and return passages formed corresponding to the second raceway grooves, end caps mounted on forward and aft end faces of the casing, each to each end face, and provided therein with turnarounds connecting the second raceway grooves to the return passages, rolling elements running through recirculating passages composed of curved raceways defined between the first and second raceway grooves, the turnarounds and the return passages, and end seals attached on the end caps, each to each cap;
• wherein the forward and aft end faces of the casing are each arranged such that an imaginary plane including any one of the end faces and normal to a top surface of the track rail coincides with a radial plane extending through the center of curvature of the track rail, and the return passages are opened on the forward and aft end faces at locations that are closer to a centroidal axis of the track rail than locations where the raceways are made open of the forward and aft end faces, and
• wherein the casing is made with admission holes through which a desired number of the rolling elements may be charged into the recirculating passages, and the admission holes are communicated to the return passages and may be closed with plugs.

A curvilinear motion guide unit comprising a track rail extending curved with a preselected curvature and having lengthwise side surfaces made thereon with first raceway grooves, and a slider fitting astride over the track rail for movement in a sliding manner along the track rail;

• wherein the slider is comprised of a casing provided with second raceway grooves extending curved in conformity with the first raceway grooves and return passages formed corresponding to the second raceway grooves, end caps mounted on forward and aft end faces of the casing, each to each end face, and provided therein with turnarounds connecting the second raceway grooves to the return passages, rolling elements running through recirculating passages composed of curved raceways defined between the first and second raceway grooves, the turnarounds and the return passages, and end seals attached on the end caps, each to each cap;
• wherein the forward and aft end faces of the casing are each arranged such that an imaginary plane including any one of the end faces and normal to a top surface of the track rail coincides with a radial plane extending through the center of curvature of the track rail, and the return passages are opened on the forward and aft end faces at locations that are closer to a centroidal axis of the track rail than locations where the raceways are made open of the forward and aft end faces, and
• wherein the end cap is cut deep to form a slit open to the side facing the track rail so that the end cap, when fitting astride over the track rail, may be stretched apart at the slit to be easily placed over the track rail.

A curvilinear motion guide unit comprising a track rail extending curved with a preselected curvature and having lengthwise side surfaces made thereon with first raceway grooves, and a slider fitting astride over the track rail for movement in a sliding manner along the track rail;

• wherein the slider is comprised of a casing provided with second raceway grooves extending curved in conformity with the first raceway grooves and return passages formed corresponding to the second raceway grooves, end caps mounted on forward and aft end faces of the casing, each to each end face, and provided therein with turnarounds connecting the second raceway grooves to the return passages, rolling elements running through recirculating passages composed of curved raceways defined between the first and second raceway grooves, the turnarounds and the return passages, and end seals attached on the end caps, each to each cap;
• wherein the forward and aft end faces of the casing are each arranged such that an imaginary plane including any one of the end faces and normal to a top surface of the track rail coincides with a radial plane extending through the center of curvature of the track rail, and the return passages are opened on the forward and aft end faces at locations that are closer to a centroidal axis of the track rail than locations where the raceways are made open of the forward and aft end faces, and
• wherein the end seal is composed of a rubber plate and a metal backing plate bonded to the rubber plate, the metal backing plate being comprised of a pair of backing halves to be stretched apart from each other when the end seal is placed astride over the track rail.