Abstract: An apparatus enables a high quality test to be carried out within a short time, without forcing a severe design limitation on the designer and without an expensive tester. The apparatus includes a pattern generator built in an integrated circuit to generate pseudo random patterns as test patterns. A plurality of shift registers are configured with sequential circuit elements inside said integrated circuit. An automatic test pattern generating unit generates ATPG patterns. A pattern modifier modifies a portion, to which a predetermined value is required to be set in order to detect a fault, in said pseudo random patterns generated by said pattern generator, on a basis of said ATPG patterns, and inputs said modified pseudo random patterns to said shift registers.

Abstract: A computer calculates bit patterns of syndromes for all candidate bit patterns of reception words that are input in ECC-EOR circuits of a logic circuit. The bit patterns of the syndromes are stored as possible bit patterns. Request bit patterns are propagated when an error occurs, and are allocated to the syndromes. Implication processing is performed, and the request bit patterns are compared with the possible bit patterns.

Abstract: An ATPG unit permits allocation of a don't care X as a state for activating a propagating path of a failure and, after a change in network, transfers the state from the don't care X to an uncontrol value, thereby activating the propagating path of the failure. Further, the ATPG unit supplies a system clock as a sending clock to a sending FF, gives a change to the network from the sending FF, propagates the change, supplies the system clock as a receiving clock to a receiving FF, and captures the network change, thereby propagating a state for detecting a delay failure to a path between the sending FF and the receiving FF and generating a test pattern when the propagation succeeds.

Abstract: A ball screw apparatus which can suppress retaining pieces from contacting a wall of a ball rolling path or ball circulating path, and suppress the retaining pieces between the balls from falling down, so that such a ball screw apparatus can be improved in noise reduction, operability and endurance. The retaining piece is rounded at an edge portion opposite to the ball, such that a radius of curvature of the edge portion is defined to be 0.05 mm to 1 mm, and the outer diameter of the retaining piece is in a range of 0.60 times or more to 0.85 times or less of the diameter of the ball.

Abstract: A ball screw which is little subject to deterioration of operating characteristics and occurrence of wear, torque change, noise, vibration, etc. during operation due to stagnation or competition of balls. The ball screw includes a screw shaft having a helical thread groove formed on the outer surface thereof and a nut having a thread groove formed on the inner surface thereof corresponding to the thread groove on the screw shaft which engages with the screw shaft with the interposition of a number of balls rollably provided in a helical ball rolling path formed between the two thread grooves, and spacers between adjacent ones of the number of balls, wherein the variation of the total of the gap between the balls and spacers during the rolling of the balls is smaller than 1/20 of the diameter of the ball.

Abstract: The present invention is a test pattern generating method. And the test pattern generating method provides a counting step for counting the number of faults becoming undetectable respectively, at each of states 0 and 1 that are able to be given to each of input pins of EOR gates when each of the EOR gates becomes a D frontier (different frontier) or a J frontier (justify frontier), a selecting step for selecting a state in which the number of faults becoming undetectable is smaller in the 0 and 1 states as an allocating state to the input pin, based on a counted result at the counting step, and step for generating the test pattern based on a selected state at the selecting step. With this, dynamic compaction can be effectively executed by restraining the increase of the number of test patterns.

Abstract: An ATPG unit permits allocation of a don't care X as a state for activating a propagating path of a failure and, after a change in network, transfers the state from the don't care X to an uncontrol value, thereby activating the propagating path of the failure. Further, the ATPG unit supplies a system clock as a sending clock to a sending FF, gives a change to the network from the sending FF, propagates the change, supplies the system clock as a receiving clock to a receiving FF, and captures the network change, thereby propagating a state for detecting a delay failure to a path between the sending FF and the receiving FF and generating a test pattern when the propagation succeeds.

Abstract: A ball screw which is little subject to deterioration of operating characteristics and occurrence of wear, torque change, noise, vibration, etc. during operation due to stagnation or competition of balls. The ball screw includes a screw shaft having a helical thread groove formed on the outer surface thereof and a nut having a thread groove formed on the inner surface thereof corresponding to the thread groove on the screw shaft which engages with the screw shaft with the interposition of a number of balls rollably provided in a helical ball rolling path formed between the two thread grooves, wherein the variation of the total of the gap between the balls during the rolling of the balls is smaller than {fraction (1/20)} of the diameter of the ball.

Abstract: A ball screw apparatus is provided with a screw shaft having a spiral ball screw groove, a nut member having a screw groove, and a plurality of balls. A smoothly continuous worked portion is formed at a portion of the screw groove by grinding a corner portion between the screw groove and a connecting way. The worked portion is formed such that the distance between the screw grooves is gradually reduced regarding an advancing direction of the ball entering from the connecting way in between the screw grooves. This worked portion extends from an end of the connecting way in a circumferential direction of the nut member and within a range of 90° from the corner portion along the circumferential direction of the nut member.

Abstract: The invention provides a ball screw which is little subject to deterioration of operating characteristics and occurrence of wear, torque change, noise, vibration, etc. during operation due to stagnation or competition of balls. A ball screw comprising a screw shaft having a helical thread groove formed on the outer surface thereof and a nut having a thread groove formed on the inner surface thereof corresponding to the thread groove on the screw shaft which engages with the screw shaft with the interposition of a number of balls rollably provided in a helical ball rolling path formed between the two thread grooves, wherein the variation of the total of the gap between said balls during the rolling of the balls is smaller than {fraction (1/20)} of the diameter of the ball.

Abstract: The invention provides a ball screw apparatus which suppresses abrasion and damage by competition of balls, controls spaces between retaining pieces and balls, and prevents retaining pieces from falling, thereby enabling to more improve operating ability. The retaining pieces are positioned between the balls running in a ball rolling path, such that a sum total of the spaces between the retaining pieces and the balls is 50% or less of an outer diameter size of the retaining piece, and at the same time a contact angle between the retaining piece and the ball is 25° or above to 40° or below.

Abstract: The invention is to offer a ball screw apparatus which can suppress retaining pieces from contacting a wall of a ball rolling path or ball circulating path, and suppress the retaining pieces between the balls from falling down, so that such a ball screw apparatus can be offered which enables to more improve low noises, operationability and endurance. The holding piece is rounded at an edge portion opposite to the ball, such that a radius of curvature of the edge portion is defined to be 1 mm or less, and the outer diameter of the retaining piece is determined to range 0.60 times or more to 0.85 times or less of the diameter of the ball.

Abstract: The invention provides a ball screw which is little subject to deterioration of operating characteristics and occurrence of wear, torque change, noise, vibration, etc. during operation due to stagnation or competition of balls. A ball screw comprising a screw shaft having a helical thread groove formed on the outer surface thereof and a nut having a thread groove formed on the inner surface thereof corresponding to the thread groove on the screw shaft which engages with the screw shaft with the interposition of a number of balls rollably provided in a helical ball rolling path formed between the two thread grooves, wherein the variation of the total of the gap between said balls during the rolling of the balls is smaller than {fraction (1/20)} of the diameter of the ball.

Abstract: A ball screw apparatus comprises a screw shaft, a nut, and a plurality of balls. A first helical groove is formed at an outer peripheral surface of the screw shaft. A second helical groove is formed at an inner peripheral surface of the nut. A rolling contact way of balls is defined by the first helical groove and the second helical groove facing each other. A connecting way formed of a tube for connecting a part and another part of the rolling contact way is provided on the nut. An endlessly communicating circuit is defined by the connecting way and the rolling contact way. Each of the balls is endlessly arranged in the circuit. A smoothly continuous machined portion is formed by cutting out an angular portion between the helical groove and the connecting way of the nut.

Abstract: An apparatus enables a high quality test to be carried out within a short time, without forcing a severe design limitation on the designer and without an expensive tester. The apparatus comprises a pattern generator built in an integrated circuit to generate a test pattern, a plurality of shift registers configured with sequential circuit elements F/Fs inside the integrated circuit, and a pattern modifier modifying the test pattern generated by the pattern generator according to an external input, and inputting it to the plural shift registers. The apparatus is used as a testing apparatus for detecting manufacturing failure of an integrated circuit such as an LSI (Large Scale Integration) or the like.

Abstract: In a ball screw according to the present invention, four circulation passages forming a circulation route are respectively arranged in the axial direction of the ball screw. The mounting positions of the second and third circulation passages A2 and A3 are set at positions which are reversed 180 degrees in the circumferential direction thereof with respect to the mounting positions of the first and fourth circulation passages A1 and A4. Accordingly, it is possible to provide a ball screw which can reduce variations in a load distribution along the axial direction of the ball screw caused by moments around a surface perpendicular to the axis of the ball screw that are generated by shifting circumferential-direction phases between circulation passages forming a circulation route from one another.

Abstract: A ball screw apparatus is provided with a screw shaft having a spiral ball screw groove, a nut member having a screw groove, and a plurality of balls. A smoothly continuous worked portion is formed at a portion of the screw groove by grinding a corner portion between the screw groove and a connecting way. The worked portion is formed such that the distance between the screw grooves is gradually reduced regarding an advancing direction of the ball entering from the connecting way in between the screw grooves. This worked portion extends from an end of the connecting way in a circumferential direction of the nut member and within a range of 90° from the corner portion along the circumferential direction of the nut member.

Abstract: A fault simulation method in which a sufficient diagnostic rate is ensured by enabling a fault in a circuit area forward of a storage element to be handled as an object to be detected, to thereby increase the speed of detection of a fault; i.e., the speed of fault simulation. In the fault simulation method, the integrated circuit is divided into a backward circuit area, which is a combinational circuit area on the output-pin side of a storage element included in the integrated circuit, and a forward circuit area, which is a combinational circuit area on the input-pin side of the storage element. When a fault which propagates to input pins of the storage element exists in the forward circuit area, the value of the fault at that observation time is written into the storage element, and at a later observation time the value of the fault is read from the storage element and propagated to the backward circuit area from output pins of the storage element.