Abstract: In a rack bar and a steering device using the same, an endmost tooth bottom for reducing a stress exerted on a first forging die during die forging of a rack tooth molding part is formed on the endmost side of a plurality of tooth bottoms. Specifically, the endmost tooth bottom is formed so that a depth thereof is less than a depth of an ordinary tooth bottom by a difference. This reduces an amount of flow of a material of the rack bar during formation of the endmost tooth bottom by an amount commensurate with the difference. As a result, the stress exerted on the first forging die can be reduced, and occurrence of heat checking in the first forging die can be suppressed.

Abstract: A rolling machine has a rolling die 4 that forms a male screw by pressing a steering shaft 14 which is an object to be rolled and plastically deforming an outer peripheral surface of the steering shaft 14 while rotating in contact with the outer peripheral surface of the steering shaft 14, a main spindle 3 inserted into a penetration hole 10 of the rolling die 4 and transmitting a rotation force to the rolling die 4, a key groove and a key which restrict a relative rotation between the rolling die 4 and the main spindle 3, a spiral oil groove 16 provided on an inner peripheral surface of the penetration hole 10 or an outer peripheral surface of the main spindle and extending from one end portion 10b side in an axial direction of the penetration hole in an inner axial direction of the penetration hole.

Abstract: A spring steel-made clip (22) has an arc-shaped first inserting part forcing portion (66) and an arc-shaped second inserting part forcing portion (67) facing the first inserting part forcing portion (66), a first axial direction connecting portion (68) connecting one ends of the inserting part forcing portions (66, 67) and a second axial direction connecting portion (69) connecting the other ends of the inserting part forcing portions (66, 67). The axial direction connecting portions (68, 69) have connecting end position stoppers (75, 76) protruding from their inner edge portions (68a, 69a) toward an opening (65). The connecting end position stoppers (75, 76) elastically contact position stopper contact portions (44e, 57e) of tubes (20A, 20B), then a relative movement of the tubes (20A, 20B) in a direction in which connecting end contact surfaces (47, 60) separate from each other is stopped.

Abstract: A rack housing (9) is provided with: a cylindrical main body (19) for movably accommodating a rack bar (8); and a stroke limiting section (25) annularly protruding from the cylindrical main body (19) toward a first end (9a). The inner peripheral surface (25b) of the stroke limiting section (25) is located offset radially outward from a support surface (19a), i.e. the inner peripheral surface of the cylindrical main body (19). The inner peripheral surface (25b) and the support surface (19a) are connected to each other by a sloped section (26) which is sloped circular conically. The sloped section (26) is provided at a position overlapping the cylindrical main body (19) when viewed radially. The sloped section (26) is sloped so that the inner diameter of the cylindrical main body (19) of the rack housing (9) increases toward a first contact section (25a).

Abstract: A method for manufacturing a steering shaft of a steering device includes: a reduced-diameter section forming process in which a second-phase member is formed from a first-phase member by forming a reduced-diameter section in the first-phase member; and a ball screw groove forming process in which a third-phase member is formed from the second-phase member by forming a ball screw groove in the second-phase member by rolling.

Abstract: A rack housing (9) is provided with: a cylindrical main body (19) for movably accommodating a rack bar (8); and a stroke limiting section (25) annularly protruding from the cylindrical main body (19) toward a first end (9a). The inner peripheral surface (25b) of the stroke limiting section (25) is located offset radially outward from a support surface (19a), i.e. the inner peripheral surface of the cylindrical main body (19). The inner peripheral surface (25b) and the support surface (19a) are connected to each other by a sloped section (26) which is sloped circular conically. The sloped section (26) is provided at a position overlapping the cylindrical main body (19) when viewed radially. The sloped section (26) is sloped so that the inner diameter of the cylindrical main body (19) of the rack housing (9) increases toward a first contact section (25a).

Abstract: A spring steel-made clip (22) has an arc-shaped first inserting part forcing portion (66) and an arc-shaped second inserting part forcing portion (67) facing the first inserting part forcing portion (66), a first axial direction connecting portion (68) connecting one ends of the inserting part forcing portions (66, 67) and a second axial direction connecting portion (69) connecting the other ends of the inserting part forcing portions (66, 67). The axial direction connecting portions (68, 69) have connecting end position stoppers (75, 76) protruding from their inner edge portions (68a, 69a) toward an opening (65). The connecting end position stoppers (75, 76) elastically contact position stopper contact portions (44e, 57e) of tubes (20A, 20B), then a relative movement of the tubes (20A, 20B) in a direction in which connecting end contact surfaces (47, 60) separate from each other is stopped.

Abstract: In a power steering device equipped with a rack shaft constructed by joining a first member having rack teeth and a second member serving as a ball screw shaft on which a ball screw groove is formed, a grinding process of the ball screw groove is performed on the second member by causing a grindstone to rotate and move along a rotation axis of the second member, while causing the second member to rotate about an axis of the second member as the rotation axis. The grinding process is performed so as to satisfy a specified machining condition “g/(5×p)<w<g/p”, where w is a rotational speed of the second member during grinding of the ball screw groove, g is a rotational speed of the grindstone during grinding of the ball screw groove, and p is a circumferential length of one circumference of the ball screw groove around the rotation axis.

Abstract: An object of the present invention is to provide a power steering apparatus and a method of manufacturing a power steering apparatus that allow balls to smoothly travel in a connection member for circulating the balls. To achieve this object, a first curved portion of a first connection passage of a nut that faces a first bent portion of the connection member is formed into a curved shape in such a manner that a space between the first curved portion and the first bent portion is equal to or smaller than a predetermined value. Further, a second curved portion of a second connection passage of the nut that faces a second bent portion of the connection member is formed into a curved shape in such a manner that a space between the second curved portion and the second bent portion is equal to or smaller than a predetermined value.

Abstract: A first member (81) including a first opening portion that opens to one side in a circumferential direction around an axis of a rack shaft corresponding to a rotation axis of a nut, and a second member (82) including a second opening portion that confronts the first opening portion, and that opens to the other side in the circumferential direction, are molded so that a first insertion portion (71) and a second insertion portion (72) are inclined along a lead angle of a ball circulation groove with respect to a connection portion (73), and the first and second openings are joined in an abutted state, thereby forming a tube (44).

Abstract: In a power steering device equipped with a rack shaft constructed by joining a first member having rack teeth and a second member serving as a ball screw shaft on which a ball screw groove is formed, a grinding process of the ball screw groove is performed on the second member by causing a grindstone to rotate and move along a rotation axis of the second member, while causing the second member to rotate about an axis of the second member as the rotation axis. The grinding process is performed so as to satisfy a specified machining condition “g/(5×p)<w<g/p”, where w is a rotational speed of the second member during grinding of the ball screw groove, g is a rotational speed of the grindstone during grinding of the ball screw groove, and p is a circumferential length of one circumference of the ball screw groove around the rotation axis.

Abstract: A first member (81) including a first opening portion that opens to one side in a circumferential direction around an axis of a rack shaft corresponding to a rotation axis of a nut, and a second member (82) including a second opening portion that confronts the first opening portion, and that opens to the other side in the circumferential direction, are molded so that a first insertion portion (71) and a second insertion portion (72) are inclined along a lead angle of a ball circulation groove with respect to a connection portion (73), and the first and second openings are joined in an abutted state, thereby forming a tube (44).

Abstract: A power steering system is provided with a communicating hole and yet ensures the strength of a housing. Space between the housing and a wheel turning shaft is divided into two. Space located on one axial side of the bearing supporting a nut and the plurality of balls disposed in the nut is a first chamber, and space located on the other side is a second chamber. The communicating hole allowing communication between the first and second chambers is formed in the nut to open in the nut-side ball screw groove, avoiding a region in which the balls circulate, or in a member disposed radially further outside than the nut and radially inside than the inner wall of the housing.

Abstract: A motor driving unit (1) includes a controller (15) that performs driving control of a motor (3) by controlling an inverter (11). During regeneration of the motor (3), the controller (15) performs output stopping control for causing the inverter (11) to stop an output, when an inter-terminal voltage of a capacitor (12) is equal to or greater than a first threshold value. The controller (15) performs output restarting control for causing the inverter (11) to restart the output, when the inter-terminal voltage of the capacitor (12) is equal to or smaller than a second threshold value which is smaller than the first threshold value. The controller (15) performs regenerative braking by allowing the output stopping control and the output restarting control to be repeatedly performed.

Abstract: An object of the present invention is to provide a power steering apparatus and a method of manufacturing a power steering apparatus that allow balls to smoothly travel in a connection member for circulating the balls. To achieve this object, a first curved portion of a first connection passage of a nut that faces a first bent portion of the connection member is formed into a curved shape in such a manner that a space between the first curved portion and the first bent portion is equal to or smaller than a predetermined value. Further, a second curved portion of a second connection passage of the nut that faces a second bent portion of the connection member is formed into a curved shape in such a manner that a space between the second curved portion and the second bent portion is equal to or smaller than a predetermined value.

Abstract: A power steering device provided to including: a steering shaft; a cylinder-like nut; a ball circulation groove including a steering shaft-side ball screw groove and a nut-side ball screw groove; balls; a first connecting passage; a second connecting passage; a connecting member; and an electric motor, wherein the first connecting passage has a first tapered part and the second connecting passage has a second tapered part, and the first connecting passage and the second connecting passage have an angle between the first tapered part and the second tapered part in the rotational direction of the nut, the angle being smaller than 180°.

Abstract: A motor driving unit (1) includes a controller (15) that performs driving control of a motor (3) by controlling an inverter (11). During regeneration of the motor (3), the controller (15) performs output stopping control for causing the inverter (11) to stop an output, when an inter-terminal voltage of a capacitor (12) is equal to or greater than a first threshold value. The controller (15) performs output restarting control for causing the inverter (11) to restart the output, when the inter-terminal voltage of the capacitor (12) is equal to or smaller than a second threshold value which is smaller than the first threshold value. The controller (15) performs regenerative braking by allowing the output stopping control and the output restarting control to be repeatedly performed.

Abstract: A power steering system is provided with a communicating hole and yet ensures the strength of a housing. Space between the housing and a wheel turning shaft is divided into two. Space located on one axial side of the bearing supporting a nut and the plurality of balls disposed in the nut is a first chamber, and space located on the other side is a second chamber. The communicating hole allowing communication between the first and second chambers is formed in the nut to open in the nut-side ball screw groove, avoiding a region in which the balls circulate, or in a member disposed radially further outside than the nut and radially inside than the inner wall of the housing.

Abstract: A fixation member is circularly formed to surround a wheel turning shaft and includes an abutment surface in abutment with an end surface of a bearing on one axial side. The fixation member fixes the bearing to a housing by being fixed in the housing with the abutment surface in abutment with the end surface of the bearing. When being mounted, the fixation member is provided by being moved from an opposite axial end side to one axial end side of the nut. The abutment surface of the fixation member is formed on at least a radially inner side of the fixation member. The fixation member includes a cutout portion provided on the radially inner side of the fixation member and formed to prevent interference with a circulation member when the fixation member is inserted in the housing.

Abstract: A nut is formed by a die forging process in which a die used for the die forging process is released in a direction along the direction of the axis of rotation of the nut.