According to the present invention, a low surface-roughness part (114a) is formed at a first tapered part (114), and, as a result, the roughness of an opening-edge of a groove part (113a) of an internal spline part (113) that opens at the first tapered part (114) is reduced, and surface pressure applied by the opening edge to a tooth (123b) of an external spline part (123) can be reduced. As a result, the opening edge of the groove part (113a) of the internal spline part (113) can be kept from digging into the tooth (123b), and variation, between products, in the insertion load of a second shaft part (12) can be suppressed.

A toothed shaft can be installed in a hollow shaft that has an internal toothing such that the toothed shaft is coupled in a positively locking fashion so as to be telescopic in a direction of a longitudinal axis. The toothed shaft may include a toothing region with teeth on an outer circumference and extending in an axial direction. In the toothing region a shaft core may be overmolded by way of an injection molding process with a sliding coating comprised of thermoplastic material. The sliding coating may have at least three impressions, with each of the at least three impressions featuring an aperture that extends through the sliding coating to a surface of the shaft core.

A propeller shaft for a vehicle in which a tube yoke is connected to a main tube via an adapter and tapered splines are formed at the contact regions between a tube yoke and the main tube to transmit the power output from a transmission to a rear wheel. The tube yoke and the main tube are displaced relative to each other at the tapered splines to break the adapter. The tube yoke and the main tube are thus separated from each other by virtue of the breakage of the adapter.

A spline connection having a hub with a toothing profile on the inner circumference, an axle journal having a toothing profile on an outer circumferential portion, a shoulder for axial support and/or abutment against the hub, and a tensioning device for axially bracing the axle journal with the hub. The hub has a constant toothing profile and the axle journal has a first portion and a second portion with different toothing profiles. The first portion is arranged on the insertion side to be further away from the shoulder than the second portion and has a constant toothing profile with play with respect to the toothing profile of the hub. The second portion is arranged on the shoulder side and has a toothing profile which has reduced tooth spaces compared with the first portion and which is play-free with respect to the toothing profile of the hub.

An extendable shaft includes: an inner shaft including a plurality of external teeth; an outer shaft including a plurality of internal teeth that slides relatively to the external teeth; and a resin layer covering the external teeth. The pressure angle of the external teeth is different from the pressure angle of the internal teeth.

A propeller shaft for a vehicle is provided in which a tube yoke is connected to a main tube via an adapter and tapered splines are formed at the contact regions between a tube yoke and the main tube to transmit the power output from a transmission to a rear wheel. The tube yoke and the main tube are displaced relative to each other at the tapered splines to break the adapter. The tube yoke and the main tube are thus separated from each other by virtue of the breakage of the adapter to efficiently absorb impact energy.

A steering shaft for a motor vehicle has an inner shaft, arranged in an outer shaft that is displaceable axially in the direction of an axis of rotation. The inner shaft includes axially running radial projections on its outer side. The outer shaft includes axially running grooves on its inner side, into which grooves the projections of the inner shaft engage in a positively locking manner in a direction of rotation and displaceably in an axial direction. With regard to fault-free operation during fluctuating temperatures, on the inner shaft, there is arranged a profiled sleeve with undulating cross-sectional profile, the inner surface of which lies against the flanks of the projections of the inner shaft and the outer surfaces of which lie against the flanks of the grooves of the outer shaft, wherein the profiled sleeve is connected to the inner shaft at one or more fastening points.

A modular foundation support system includes modular foundation support components including self-aligning and torque transmitting coupler features wherein a plurality of axially elongated ribs are aligned with a plurality of axially elongated ribs to rotationally interlocke the modular foundation support components to one another.

A connector system facilitates the connection of a first tree trunk to a second tree trunk of an artificial tree system. The connector system can prohibit rotation of the first tree trunk relative to the second tree trunk.

A drive shaft (7) as a rotating body includes an engaging portion (7c) engaging with a side gear (14) and a sliding portion (7b) abutted by a differential case (9). The engaging portion (7c) includes a plurality of engaging grooves (15). The engaging grooves (15) engage with the side gear (14). The engaging portion (7c) includes a small diameter portion (15d) at a position corresponding to between the drive shaft (7) and the differential case (9) in a direction of a rotational axis L1. The small diameter portion (15d) has an outer diameter smaller than the outer diameter of the sliding portion (7b).