Abstract: A ball screw device includes a threaded shaft, a nut, and balls. The nut body includes a central tubular portion and an end tubular portion. The central tubular portion has a through-hole and an end surface. The nut further includes a circulation member and a snap ring. The circulation member is provided on an inner peripheral side of the end tubular portion such that the circulation member is in contact with the end surface. The snap ring is fitted to a circumferential groove provided on an inner periphery of the end tubular portion. The snap ring is configured to fix the circulation member in a manner such that the circulation member is sandwiched between the snap ring and the end surface.

Abstract: A nut includes a circulation passage such that balls are circulated through the circulation passage from a first axial end part of rolling raceway to a second axial end part of the rolling raceway. The nut includes a nut body, and end members connected to the opposite axial ends of the nut body. The nut body includes a first member and a second member. The first member includes a second spiral groove on the inner periphery of the first member and a passage having a groove shape opened radially outwardly, the passage being formed on the outer periphery of the first member such that the passage constitutes part of the circulation passage. The second member is placed radially outwardly from the first member and closes the passage from its radially outer side.

Abstract: A ball screw device includes a screw shaft; a nut having a second helical groove; and a plurality of balls. When the screw shaft is rotated about an axis of the screw shaft while being subjected to the external force, the balls are displaced from positions under no load condition toward one side in an axial direction. A second helical groove of the nut includes a stopping member configured to prevent the balls from falling off from the second helical groove. A plurality of coil springs are arranged in series along the second helical groove. An angle in a circumferential direction occupied by each of the coil springs about the axis is 180 degrees or less when the coil springs are disposed in the second helical groove.

Abstract: A ball screw device includes a screw shaft; a nut having a second helical groove; and a plurality of balls. When the screw shaft is rotated about an axis of the screw shaft while being subjected to the external force, the balls are displaced from positions under no load condition toward one side in an axial direction. A second helical groove of the nut includes a stopping member configured to prevent the balls from falling off from the second helical groove. A plurality of coil springs are arranged in series along the second helical groove. An angle in a circumferential direction occupied by each of the coil springs about the axis is 180 degrees or less when the coil springs are disposed in the second helical groove.

Abstract: A ball screw device includes a screw shaft, a nut, a ball train including a plurality of main balls, and a plurality of coil springs disposed in the ball train. The nut moves from a first axial side to a second axial side while an axial force is applied to the nut by rotation of the screw shaft. The plurality of coil springs are more densely arranged on the first axial side than on the second axial side in the ball train.

Abstract: A ball screw device includes a screw shaft, a nut, and a housing that has a bottomed cylindrical shape and to which the nut is attached. The ball screw device converts rotational motion of the screw shaft into linear motion of the housing. The ball screw device is switched between a normal use state and a supply state. In the normal use state, along with the linear motion, a bottom portion of the housing reciprocates between a first position spaced apart from an end of the screw shaft and a second position closer to the end. In the supply state, along with the linear motion, the bottom portion of the housing is located in a third position even closer to the end of the screw shaft, such that grease present in the nut and the bottom portion of the housing is introduced to a radially inner side of the nut.

Abstract: A ball screw device includes a screw shaft, a nut, a ball train including a plurality of main balls, and a plurality of coil springs disposed in the ball train. The nut moves from a first axial side to a second axial side while an axial force is applied to the nut by rotation of the screw shaft.

Abstract: A ball screw apparatus includes a ball nut through which a ball screw shaft is inserted. A recessed portion is formed in an inner periphery of the ball nut and is recessed so as to extend in a tangential direction of a ball track. A ball train including a plurality of main balls and a coil spring are housed in a raceway. The recessed portion includes a first surface that supports a second end of the coil spring via a stopper ball and a second surface that regulates movement of the stopper ball in a nut axial direction. The second surface is inclined by an angle corresponding to a lead angle of the ball track of the ball nut from an axially perpendicular plane of the ball nut so as extend in the direction of the lead angle.

Abstract: A ball screw device includes a cylinder that surrounds the outer periphery of a ball nut. Accommodation holes are formed in the ball nut at a rolling start position and a rolling end position in ball rolling paths. An outer periphery turning groove is formed in an outer peripheral face of the ball nut, and the outer periphery turning groove and an inner peripheral face of the cylinder constitute a turning rolling path. The turning rolling path and connection passages formed in deflectors constitute a circulation path through which balls are returned from the rolling end position to the rolling start position.

Abstract: A ball screw apparatus includes a ball nut through which a ball screw shaft is inserted. A recessed portion is formed in an inner periphery of the ball nut and is recessed so as to extend in a tangential direction of a ball track. A ball train including a plurality of main balls and a coil spring are housed in a raceway. The recessed portion includes a first surface that supports a second end of the coil spring via a stopper ball and a second surface that regulates movement of the stopper ball in a nut axial direction. The second surface is inclined by an angle corresponding to a lead angle of the ball track of the ball nut from an axially perpendicular plane of the ball nut so as extend in the direction of the lead angle.

Abstract: A ball screw device includes a piston that surrounds the outer periphery of a ball nut. An outer periphery turning groove is formed in the outer peripheral face of the ball nut. The outer periphery turning groove and the inner peripheral face of a cylindrical portion of the piston constitute a turning rolling path. The turning rolling path and connection passages of deflectors constitute a returning path through which balls are returned from a rolling end position to a rolling start position. An internally-fitting portion is formed at one end portion of the ball nut in the axial direction. When the outer periphery of the internally-fitting portion and the inner periphery of the cylindrical portion are fitted to each other, relative rotation of the ball nut and the piston is prevented.

Abstract: A ball screw device includes a cylinder that surrounds the outer periphery of a ball nut. Accommodation holes are formed in the ball nut at a rolling start position and a rolling end position in ball rolling paths. An outer periphery turning groove is formed in an outer peripheral face of the ball nut, and the outer periphery turning groove and an inner peripheral face of the cylinder constitute a turning rolling path. The turning rolling path and connection passages formed in deflectors constitute a circulation path through which balls are returned from the rolling end position to the rolling start position.

Abstract: A transmission that is able to perform shift operation and select operation using the driving force of a single electric motor is provided. A shift/select actuating device includes: an electric motor; a first conversion mechanism; a second conversion mechanism; and a changing unit that changes a destination, to which the rotational driving force of the electric motor is transmitted, between the first conversion mechanism and the second conversion mechanism. The changing unit includes: a first electromagnetic clutch that transmits the rotational driving force of the electric motor to the first conversion mechanism or interrupts the rotational driving force; and a second electromagnetic clutch that transmits the rotational driving force to the second conversion mechanism or interrupts the rotational driving force.

Abstract: A transmission that is able to perform shift operation and select operation using the driving force of a single electric motor is provided. A shift/select actuating device includes: an electric motor; a first conversion mechanism; a second conversion mechanism; and a changing unit that changes a destination, to which the rotational driving force of the electric motor is transmitted, between the first conversion mechanism and the second conversion mechanism. The changing unit includes: a first electromagnetic clutch that transmits the rotational driving force of the electric motor to the first conversion mechanism or interrupts the rotational driving force; and a second electromagnetic clutch that transmits the rotational driving force to the second conversion mechanism or interrupts the rotational driving force.

Abstract: A drive power transmission device is disclosed having a drive mechanism for transmitting a drive power between first and second rotary members rotatable relative to each other, by the operation of an electromagnetic type clutch mechanism which brings a friction clutch into connection. A magnetic path generated around an electromagnet of the electromagnetic type clutch mechanism includes a clutch magnetic path in which a magnetic flux passes to reciprocate plural times across th friction clutch, and diamond-like carbon surface treatment is given on a part or all of the friction contact surfaces of the friction clutch to form a hard amorphous carbon film thereon. Thus, the transmission device can be constructed using a smaller number of the outer and inner plates for the electromagnetic type clutch mechanism, so that it can take a small construction with a longer durability life.

Abstract: A friction clutch has a plurality of iron inner clutch plates and a plurality of iron outer clutch plates. Both the clutch plates have sliding surfaces which are friction-engaged each other. A thin carbon film in a diamond form, which functions as a solid lubricant, is formed on each of the sliding surfaces of the outer clutch plates by a known method such as the Chemical Vapor Deposition method. A known nitride treatment or quenching and tempering treatment is applied to the sliding surfaces of the inner clutch plates. A coupling device has a pilot clutch mechanism with the friction clutch and an electromagnetic actuator. As a result, the friction clutch is resistant to wear and the coupling device is excellent in durability.

Abstract: A friction clutch has a plurality of iron inner clutch plates and a plurality of iron outer clutch plates. Both the clutch plates have sliding surfaces which are friction-engaged each other. A thin carbon film in a diamond form, which functions as a solid lubricant, is formed on each of the sliding surfaces of the outer clutch plates by a known method such as the Chemical Vapor Deposition method. A known nitride treatment or quenching and tempering treatment is applied to the sliding surfaces of the inner clutch plates. A coupling device has a pilot clutch mechanism with the friction clutch and an electromagnetic actuator. As a result, the friction clutch is resistant to wear and the coupling device is excellent in durability.

Abstract: A drive power transmission device is disclosed having a drive mechanism for transmitting a drive power between first and second rotary members rotatable relatlve to each other, by the operation of an electromagnetic type dutch mechanism which brings a friction clutch into connection. A magnetic path generated around an electromagnet of the electromagnetic type clutch mechanism includes a clutch magnetic path in which a magnetic flux passes to reciprocate plural times across th friction clutch, and diamond-like carbon surface treatment is given on a part or all of the friction contact surfaces of the friction clutch to form a hard amorphous carbon film thereon. Thus, the transmission device can be constructed using a smaller number of the outer and inner plates for the electromagnetic type clutch mechanism, so that it can take a small construction with a longer durability life.

Abstract: A friction clutch has a plurality of iron inner clutch plates and a plurality of iron outer clutch plates. Both the clutch plates have sliding surfaces which are friction-engaged each other. A thin carbon film in a diamond form, which functions as a solid lubricant, is formed on each of the sliding surfaces of the outer clutch plates by a known method such as the Chemical Vapor Deposition method. A known nitride treatment or quenching and tempering treatment is applied to the sliding surfaces of the inner clutch plates. A coupling device has a pilot clutch mechanism with the friction clutch and an electromagnetic actuator. As a result, the friction clutch is resistant to wear and the coupling device is excellent in durability.

Abstract: In a machine tool having a worktable feed mechanism of the type that a worktable is moved in a horizontal direction relative to a tool spindle along a pair of guideways in parallel with the horizontal direction, there is provided a cutting chips collection space formed between the pair of guideways fixed to a base. A pair of ball screws are arranged outside of the cutting chips collection space for moving the worktable relative to the tool spindle in the horizontal direction. The cutting chips and coolant generated by contacting a tool with a workpiece drop into the cutting chips collection space directly without being heaped onto a cover mechanism of the worktable feed mechanism.