Abstract: A telescopic shaft (5) has an inner shaft (12) and a tubular outer shaft (13) that are fitted to each other so that they can move relative to each other in the axial direction and that they can transmit torque to each other. A plurality of balls (14) are aligned between respective raceway grooves (15; 16) of the inner shaft (12) and the outer shaft (13). Limiting mechanisms (20A; 20B) are provided that limit the amount of relative rotation to not more than a predetermined amount of the inner shaft (12) and the outer shaft (13) when a ball (14) comes off the raceway grooves (15; 16). The limiting mechanisms (20A; 20B) include a pair of engagement sections (21, 22; 23, 24) engageable with each other in a circumferential direction (C1). The engagement sections (21, 22; 23, 24) are provided at ridges (25, 26) and recesses (27, 28) that are adjacent to the raceway grooves (15; 16) of the inner shaft (12) and the outer shaft (13), respectively.

Abstract: A telescopic shaft (5) has an inner shaft (12) and tubular outer shaft (13) that are fitted to each other so that they can move relative to each other in the axial direction and that they can transmit torque to each other. A row of balls (14) is placed in respective raceway grooves (15; 16) of the inner shaft (12) and the outer shaft (13). Limiting mechanisms (20A; 20B) are provided in the telescopic shaft (5), and the mechanisms limit the amount of relative rotation of the inner shaft (12) and the outer shaft (13) when a ball (14) comes off the raceway grooves (15; 16). The limiting mechanisms (20A; 20B) include a pair of engagement sections (21, 22; 23, 24) engaging with each other in a circumferential direction (C1). The engagement sections (21, 22; 23, 24) are provided at ridges (25, 26) and recesses (27, 28), and the ridges (25, 26) and recesses (27, 28) are adjacent to the raceway grooves (15; 16) of the inner shaft (12) and the outer shaft (13), respectively.

Abstract: An extendable shaft (5), comprising an inner shaft (12) and a tubular outer shaft (13) fitted axially relatively movable so that a torque can be transmitted to each other. A plurality of balls (14) aligned are interposed between the corresponding raceway grooves (15, 16) of the inner shaft (12) and the outer shaft (13). Each of the raceway grooves (15, 16) has a predetermined cross section. As a result, the contact angle (A1) of the balls (14) to the raceway grooves (15, 16) is zero at no-load and can be gradually increased according to an increase in load torque.

Abstract: In a hydraulic power steering apparatus, when the relative rotation between input and output shafts which are connected by a torsion bar is converted into the relative rotation between an outer valve element and an inner valve element, the ratio of the relative rotation angle of the latter to the relative rotation angle of the former is varied in accordance with an operating condition of a vehicle. The hydraulic pressure to generate steering assist force is controlled in accordance with the relative rotation angles between both valve elements. The outer valve element is capable of relative coaxial rotation to the input and output shafts, and the inner valve element is formed integrally with the input shaft. A swinging member is supported by first, second and third supporting parts which respectively rotate together with the input shaft, the output shaft or the outer valve element.

Abstract: In a hydraulic power steering apparatus, when the relative rotation between input and output shafts which are connected by a torsion bar is converted into the relative rotation between an outer valve element and an inner valve element, the ratio of the relative rotation angle of the latter to the relative rotation angle of the former is varied in accordance with an operating condition of a vehicle. The hydraulic pressure to generate steering assist force is controlled in accordance with the relative rotation angles between both valve elements. The outer valve element is capable of relative coaxial rotation to the input and output shafts, and the inner valve element is formed integrally with the input shaft. A swinging member is supported by first, second and third supporting parts which respectively rotate together with the input shaft, the output shaft or the outer valve element.