Abstract: A rotor includes: a shaft; a rotor back yoke having a through hole defined in an axial center through which the shaft is inserted, the rotor back yoke being integrally and rotatably connected to the shaft; and magnets fixed to an outer peripheral surface of the rotor back yoke, the plurality of magnets being disposed with magnetic poles of different polarities being arranged alternately along a circumferential direction. The rotor back yoke includes a plurality of first cutout portions provided at predetermined intervals in the circumferential direction and extending from an inner peripheral surface of the rotor back yoke outward in a radial direction. Each of the plurality of first cutout portions extends along an axial direction, from one end surface to the other end surface of the rotor back yoke.

Abstract: A spline telescoping shaft includes an inner shaft including a male spline and a tubular outer shaft including a female spline. A resin film is provided on a surface of at least either of both the splines. An addendum modification coefficient e, the number of teeth Z, a module m, a reference pitch circle diameter PCD, a tip circle diameter d1 and a root circle diameter d2 of the male spline and a tip circle diameter D1 and a root circle diameter D2 of the female spline have relations expressed by expressions (1) to (8). m(Z+4)>d1>m(Z+2)??(1), mZ>d2>m(Z?1)??(2), m(Z+4)>D2>m(Z+2)??(3), mZ>D1>m(Z?1)??(4), D2>d1??(5), D1>d2??(6), PCD=mZ??(7), and 0.4<e<1.

Abstract: A telescopic shaft includes a hollow outer shaft, an inner shaft spline-fitted to the outer shaft, a resin coating provided on splines on at least one of the outer and inner shafts, and can be extended and contracted in an axial direction. A method for manufacturing the telescopic shaft includes press-fitting the inner shaft into the outer shaft and sliding one of the outer and inner shafts relative to the other of the outer and inner shafts by reciprocating the one shaft in the axial direction. In the sliding, a frequency according to a sliding speed at which the one shaft is slid relative to the other shaft is set to be lower than a predetermined value at the start of sliding, and the frequency is increased in a continuous or stepwise manner when a sliding load of the one shaft to the other shaft is reduced.

Abstract: A spline telescoping shaft includes an inner shaft including a male spline and a tubular outer shaft including a female spline. A resin film is provided on a surface of at least either of both the splines. An addendum modification coefficient e, the number of teeth Z, a module m, a reference pitch circle diameter PCD, a tip circle diameter d1 and a root circle diameter d2 of the male spline and a tip circle diameter D1 and a root circle diameter D2 of the female spline have relations expressed by expressions (1) to (8). m(Z+4)>d1>m(Z+2) . . . (1), mZ>d2>m(Z?1) . . . (2), m(Z+4)>D2>m(Z+2) . . . (3), mZ>D1>m(Z?1) . . . (4), D2>d1 . . . (5), D1>d2 . . . (6), PCD=mZ . . . (7), and 0.4<e<1.1 . . .

Abstract: A method of manufacturing a spline telescopic shaft, includes a sliding step of sliding in an axial direction an inner shaft manufacturing intermediate member and an outer shaft manufacturing intermediate member, in one of which a resin coating is disposed on splines. In the sliding step, a sliding load of the inner shaft manufacturing intermediate member and the outer shaft manufacturing intermediate member is detected, and sliding is ended at a timing when the detected sliding load reaches a threshold load which is determined based on an initial sliding load detected at a start of the sliding.

Abstract: A telescopic shaft includes an inner shaft and a cylindrical outer shaft that are fitted together. A first raceway groove extending in the axial direction is formed in an outer peripheral surface of the inner shaft. A second raceway groove extending in the axial direction and facing the first raceway groove is formed in an inner peripheral surface of the outer shaft. A plurality of balls interposed between the first and second raceway grooves and arranged in a row in the axial direction roll in a first stroke range in the axial direction with respect to the inner shaft and roll in a second stroke range in the axial direction with respect to the outer shaft as the inner and outer shafts move relative to each other in the axial direction. The depth of the first raceway groove decreases from the middle toward both ends of the first stroke range.

Abstract: A telescopic shaft includes a hollow outer shaft, an inner shaft spline-fitted to the outer shaft, a resin coating provided on splines on at least one of the outer and inner shafts, and can be extended and contracted in an axial direction. A method for manufacturing the telescopic shaft includes press-fitting the inner shaft into the outer shaft and sliding one of the outer and inner shafts relative to the other of the outer and inner shafts by reciprocating the one shaft in the axial direction. In the sliding, a frequency according to a sliding speed at which the one shaft is slid relative to the other shaft is set to be lower than a predetermined value at the start of sliding, and the frequency is increased in a continuous or stepwise manner when a sliding load of the one shaft to the other shaft is reduced.

Abstract: A method of manufacturing a spline telescopic shaft, includes a sliding step of sliding in an axial direction an inner shaft manufacturing intermediate member and an outer shaft manufacturing intermediate member, in one of which a resin coating is disposed on splines. In the sliding step, a sliding load of the inner shaft manufacturing intermediate member and the outer shaft manufacturing intermediate member is detected, and sliding is ended at a timing when the detected sliding load reaches a threshold load which is determined based on an initial sliding load detected at a start of the sliding.

Abstract: A motor vehicle steering shaft (3) is provided with: an inner shaft (11) and a tubular outer shaft (10) fitted into each other and to transmit a torque to and from each other; a rigid coupling element (25) for rigidly coupling the inner shaft (11) and the outer shaft (10) in a circumferential direction (C) of the inner shaft (11) when a relative rotation amount of the inner shaft (11) and the outer shaft (10) exceeds a predetermined range; and an elastic coupling element (36) for elastically coupling the inner shaft (11) and the outer shaft (10) in the circumferential direction (C) of the inner shaft (11) when the relative rotation amount of the inner shaft (11) and the outer shaft (10) is within the predetermined range. The elastic coupling element (36) includes a resin member (36). The inner shaft (11) and the outer shaft (10) are elastically supported mutually via the resin member (36) at a central position of the predetermined range when no torque is loaded to the steering shaft (3).

Abstract: A motor vehicle steering shaft (3) is provided with: an inner shaft (11) and a tubular outer shaft (10) fitted into each other and to transmit a torque to and from each other; a rigid coupling element (25) for rigidly coupling the inner shaft (11) and the outer shaft (10) in a circumferential direction (C) of the inner shaft (11) when a relative rotation amount of the inner shaft (11) and the outer shaft (10) exceeds a predetermined range; and an elastic coupling element (36) for elastically coupling the inner shaft (11) and the outer shaft (10) in the circumferential direction (C) of the inner shaft (11) when the relative rotation amount of the inner shaft (11) and the outer shaft (10) is within the predetermined range. The elastic coupling element (36) includes a resin member (36). The inner shaft (11) and the outer shaft (10) are elastically supported mutually via the resin member (36) at a central position of the predetermined range when no torque is loaded to the steering shaft (3).

Abstract: An extendable shaft for steering vehicle rotated according to the steering of a steering member comprises: an inner shaft and a tubular outer shaft fitted with each other in a manner to be capable of relative sliding movement; a rigid coupling element for rigidly interconnecting the inner shaft and the outer shaft in a circumferential direction of the inner shaft when a relative phase of the inner shaft and the outer shaft with respect to the circumferential direction exceeds a predetermined range; at least three pairs of axial grooves individually formed on an outer periphery of the inner shaft and an inner periphery of the outer shaft and opposed to each other; and a plurality of elongate resin rods as elastic coupling elements for elastically interconnecting the inner shaft and the outer shaft in the circumferential direction when the relative phase thereof is in the predetermined range. Each of the plural resin rods is interposed between the mutually corresponding axial grooves.

Abstract: A telescopic shaft for steering vehicle includes: an inner shaft and a tubular outer shaft fitted with each other; at least three pairs of axial grooves formed on an outer periphery of the inner shaft and an inner periphery of the outer shaft; a rigid coupling element for rigidly connecting the inner shaft and the outer shaft in a circumferential direction of the inner shaft when a relative phase of the inner shaft and the outer shaft with respect to the circumferential direction exceeds a predetermined range; and a plurality of elongate resin rods as elastic coupling elements for elastically connecting the inner shaft and the outer shaft in the circumferential direction when the relative phase is in the predetermined range. Each of the plural resin rods is formed with a groove. A section of the groove is shaped like U opening toward the outside in a radial direction of the inner shaft.