A propeller shaft includes a shaft part and a a first yoke having a fixing portion, a connecting portion, a first yoke portion and a first concave portion. The connecting portion is provided apart from a first concave portion in the direction of the rotation axis of the shaft part. An outside diameter of the connecting portion is greater than an outside diameter of the shaft part in a radial direction of the rotation axis of the shaft part.

A coupling device according to the present invention includes: a first coupling member having first teeth on a disk surface; a second coupling member having second teeth on the disk surface; and a fastening member fastening the first coupling member and the second coupling member at central portions. A reference surface is a surface parallel to the disk surface. A tooth surface angle is an acute angle formed between a tangent line of the meshing tooth surface and a reference surface at a point C on an intersection line between the reference surface and the meshing tooth surface of the first tooth and the second tooth, in a cross section perpendicular to a radial direction of the first coupling member. Tooth surface angles and of the first tooth change along the radial direction of the first coupling member.

A coupling device according to the present invention includes: a first coupling member having first teeth on a disk surface; a second coupling member having second teeth on the disk surface; and a fastening member fastening the first coupling member and the second coupling member at central portions. A reference surface is a surface parallel to the disk surface. A tooth surface angle is an acute angle formed between a tangent line of the meshing tooth surface and a reference surface at a point C on an intersection line between the reference surface and the meshing tooth surface of the first tooth and the second tooth, in a cross section perpendicular to a radial direction of the first coupling member. Tooth surface angles and of the first tooth change along the radial direction of the first coupling member.

The present invention relates to a water turbine in which a unit pipe can be joined by an optional number and a rotating shaft integrated with a rotor can be joined by an optional number according to intended use or condition of use, and by which each rotor can be supported stably. A water turbine in which a rotor provided in a water conduit pipe is rotated by a water flow in the water conduit pipe and the rotation of the rotor is utilized as a motive power, wherein pluralities of the unit pipes constituting a part of the water conduit pipe are connected in order by interposing an end plate having a bearing and a water passing part between respective them, wherein pluralities of rotating shafts respectively integrated with the rotor are linearly connected by providing a connecting means between respective them while end portions opposing to each other of a pair of adjacent rotating shafts are brought into contact, wherein each of the rotating shafts is rotatably supported by respective pair of bearings arranged to neighbor each other such that at least one of the rotors is arranged between the respective pair of bearings, and thereby forming a water turbine unit.

A bushing including a body portion including a cylinder portion having a bore there through configured to receive a bolt; a flange portion orthogonal and integral to the cylinder portion, the flange portion configured to abut a load bearing surface of a flange; a lip portion orthogonal to and integral to the flange portion proximate the cylinder portion, wherein the lip portion redistributes a flange load.

A fitting structure includes an annular seal member; a first fitting member including a first tubular fitting portion having a tubular shape, a first holding portion that contacts the seal member from a first axial end side, and a first restricting portion provided at a position different from a position of the first holding portion; and a second fitting member including a second tubular fitting portion having a tubular shape that is fitted to the first tubular fitting portion from a second axial end side, a second holding portion that contacts the seal member from the second axial end side, and a second restricting portion that contacts the first restricting portion from the second axial end side in a state where the seal member is compressed by a prescribed amount between the first holding portion and the second holding portion.

A fitting structure includes an annular seal member; a first fitting member including a first tubular fitting portion having a tubular shape, a first holding portion that contacts the seal member from a first axial end side, and a first restricting portion provided at a position different from a position of the first holding portion; and a second fitting member including a second tubular fitting portion having a tubular shape that is fitted to the first tubular fitting portion from a second axial end side, a second holding portion that contacts the seal member from the second axial end side, and a second restricting portion that contacts the first restricting portion from the second axial end side in a state where the seal member is compressed by a prescribed amount between the first holding portion and the second holding portion.

A coupling device for the torque-transmitting connection of a transmission with an electric machine, includes a drive element and an output element which are coupled with each other in a torque-transmitting manner. The drive element and the output element are electrically separated from each other by way of an electrical insulator.

A coupling device for the torque-transmitting connection of a transmission with an electric machine, includes a drive element and an output element which are coupled with each other in a torque-transmitting manner. The drive element and the output element are electrically separated from each other by way of an electrical insulator.

A hub of a centrifugal clutch is mounted to a crankshaft of an engine. The hub includes: a hub boss at a center of the hub; a hub flange contiguous to an outer periphery of the hub boss; and a clutch element held to the hub flange. The hub boss is fastened to one end portion of the crankshaft with a plurality of fastening members extending parallel to the rotary shaft.