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 apparatus has a screw shaft having an outer peripheral surface on which a shaft track groove is formed, a nut moving along with the screw shaft and having front and back end portions and an inner peripheral surface on which a nut track groove is formed and a contact-type seal member provided on each of the front and back end portions of the nut, a groove sliding contact portion is provided on the seal member sliding contacting with the shaft track groove. A first sealing lip is formed on a first outer peripheral of the groove sliding contact portion so as to sliding contact with a first inner surface of the shaft track groove which is defined between a groove bottom center thereof and an edge thereof which is located on a front-side of the moving direction of the nut.

Abstract: An electron beam exposure apparatus, which exposes patterns on a wafer by an electron beam, includes an electron beam producing unit which produces the electron beam and an electron beam shaping member having a plurality of openings which shape the electron beam. The 1st ratio, which is a ratio between opening width of the 1st opening among the plurality of the openings in the 1st direction, which is substantially perpendicular to irradiation direction of the electron beam, and pattern width of the pattern, which should be exposed on the wafer by the electron beam shaped by the 1st opening, in the direction corresponding to the 1st direction, and the 2nd ratio, which is a ratio between opening width of the 2nd opening among the plurality of the openings, in the 1st direction, and pattern width of the pattern, which should be exposed on the wafer by the electron beam shaped by the 2nd opening, in the direction corresponding to the 1st direction, are different.

Abstract: An electron beam exposure apparatus for exposing a pattern accurately even if the current of the electron beam is high. The electron beam exposure apparatus 100 includes a mask 30 with a first and second block patterns for shaping the electron beam. Magnification of the first block pattern to a first exposure pattern which is to be exposed by the electron beam having a first current shaped by the first block pattern is different with magnification of the second block pattern to a second exposure pattern which is to be exposed by the electron beam having a second current shaped by the second block pattern.

Abstract: In a production method for producing a compound semiconductor single crystal by LEC method using a crystal growth apparatus with a double crucible structure, it was made to grow up a crystal by covering the second crucible with a plate-like member having a pass-through slot for being capable of introducing a crystal pulling-up shaft having a seed crystal holding part at a tip into the second crucible and creating a state where an atmosphere within the second crucible scarcely changes (a semi-sealed structure).

Abstract: One end of a cylinder disposed on the outer periphery of a ball screw shaft is fixed to the end face of a ball nut, while the other end of the cylinder is closed by an end plate to thereby form a lubricant filling space between the end plate and the leading end face of the ball screw shaft. And, the lubricant is supplied into the lubricant filling space from a grease nipple mounted on the cylinder.

Abstract: A ball screw has a screw shaft including a screw groove formed in an outer peripheral surface thereof; a nut including a screw groove formed in an inner peripheral surface thereof and screwed together with the screw shaft through a large number of balls rollably disposed in a spiral-shaped ball rolling passage formed by the two screw grooves; and, two seals respectively disposed on the two end portions of the nut for sealing the opening of a clearance between the screw shaft and the nut, wherein two annular grooves are respectively formed in the inner peripheral surfaces of the two end portions of the nut, each of the seals is formed in a substantially annular-ring shape having an outside diameter larger than the inside diameter of the nut and the seals are mounted into the nut by fitting the outer edge portions of the seals into the annular grooves.

Abstract: An electron beam exposure apparatus for exposing a pattern accurately even if the current of the electron beam is high. The electron beam exposure apparatus 100 includes a mask 30 with a first and second block patterns for shaping the electron beam. Magnification of the first block pattern to a first exposure pattern which is to be exposed by the electron beam having a first current shaped by the first block pattern is different with magnification of the second block pattern to a second exposure pattern which is to be exposed by the electron beam having a second current shaped by the second block pattern.

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: An electron beam exposure apparatus, which exposes patterns on a wafer by an electron beam, includes an electron beam producing unit which produces the electron beam and an electron beam shaping member having a plurality of openings which shape the electron beam. The 1st ratio, which is a ratio between opening width of the 1st opening among the plurality of the openings in the 1st direction, which is substantially perpendicular to irradiation direction of the electron beam, and pattern width of the pattern, which should be exposed on the wafer by the electron beam shaped by the 1st opening, in the direction corresponding to the 1st direction, and the 2nd ratio, which is a ratio between opening width of the 2nd opening among the plurality of the openings, in the 1st direction, and pattern width of the pattern, which should be exposed on the wafer by the electron beam shaped by the 2nd opening, in the direction corresponding to the 1st direction, are different.

Abstract: One end of a cylinder disposed on the outer periphery of a ball screw shaft is fixed to the end face of a ball nut, while the other end of the cylinder is closed by an end plate to thereby form a lubricant filling space between the end plate and the leading end face of the ball screw shaft. And, the lubricant is supplied into the lubricant filling space from a grease nipple mounted on the cylinder.

Abstract: A ball nut 30 has a dowel 60 for circulating balls 50. A cage type retainer 40 is disposed between a screw shaft 20 and the ball nut 30 which engages with the screw shaft 20 through the ball 50. The retainer 40 is provided with a plurality of elongated holes 42 at a peripheral surface thereof to extend to an axial direction thereof so as to separate the balls 50 from one another in a peripheral direction thereof and to hold the balls therein to be free to roll. The distance of a space between the screw shaft 20 and the cage type retainer 40 is set to be smaller than that of a space between the dowel 60 and the cage type retainer 40 n the radial direction of the screw shaft.

Abstract: A ball screw includes a screw shaft 2 having an external ball-screw thread 2a, at least one ball nut 3 having an internal ball-screw thread which is opposite to the external ball-screw thread 2a of the screw shaft 2, a spiral raceway formed by combination of the internal ball-screw thread of the ball nut 3 and the external ball-screw thread 2a of the screw shaft 2, a plurality of balls which are circulated through the spiral raceway, and ball return paths 5, 6, and 7 for the plurality of balls. The ball screw also includes three or more circulation circuits X, Y, Z made by the spiral raceway and the ball return paths 5, 6, and 7 formed in the ball nut 3. Of the three or more three circulation circuits X, Y, Z, at least two circulation circuits are arranged so as to be in phase with each other in the circumferential direction of the ball screw 3, and the remaining circulation circuit is positioned so as to be 180 degree out of phase with the two circulation circuits in the circumferential direction.

Abstract: An automotive vehicle equipped with an air bag system includes an interior gas discharge device for communicating a vehicle interior to the outside upon detection of a vehicular collision and a forced ventilation device provided for operation upon detection of the vehicular collision.