Helical Groove Driveshaft Wireway
Publication Date: 2015-Aug-05
The IP.com Prior Art Database
The device described is a means of securing an electrical conductor to a shaft using a tensioned wire or conduit in a helical wireway groove which is machined into the outer surface of the shaft. Applying tension to the wire in a helical groove creates an inward radial force to secure the wire in the wireway without the need for adhesives or mechanical securing devices along the length of the wireway.
This disclosure provides a simple and reliable method of securing a conductor to a driveshaft without adhesives or potting compounds. A wireway groove may be added to a shaft in to act as a conduit for an electrical conductor. This allows for the transmission of electrical power and signals between one or more components by running one or more insulated conductors along the axis of a shaft.
Having the conductors recessed into a groove on the shaft protects the conductors from damage. For rotating shafts this also protects from abrasion against non-rotating components and lowers drag forces. The recessed conductors maintain the circular cross-section of the shaft which would be required for bearings, bushing surfaces and sleeves to be installed on the driveshaft.
Wireway grooves are typically straight, running parallel to the axis of the shaft. With a straight groove an adhesive or mechanical device is requires to secure the conductors in the groove. This is usually accomplished using adhesive potting.
A spiral groove does not require adhesive or mechanical clamping along the groove to secure the conductor provided that the conductor is tensioned and secured at each end of the groove. Tension applied to a wire in a helical wireway will have an inward radial force which will keep the wire secured within the wireway without the requirement for adhesives or clamping devices along the wireway. A straight wireway would require infinite tension to have a similar effect.
Adhesives are not reliable unless surface preparation and environment control is maintained during application, which is difficult in for large shaft assemblies. In a down-hole environment, adhesives are exposed to oils and drilling mud at elevated temperatures and pressures which make them more susceptible to softening and delamination.
In a helical wireway, even if the wire were to be potted, failure of the potting would not allow the wire to come out of the wireway unless the tension on the wire is also lost. This is an advantage in high vibration applications.
Deformation of the shaft is likely a large contributor to failure of adhesive mounted wires in straight wireways since flexible adhesives typically have poor bonding strength. Rigid adhesives have good bond strength but tend to crack when deformed.
Description of Invention
In this invention, a Shaft  would be machined with a helical groove, consisting of one or more turns, on its outside diameter along its axis to form a wireway as shown in Figure 1. A Wire  consisting of one or more insulated conductors would be installed into the helical groove (Figure 2). The wire would be secured at each end of the helical groove. At least one end of the wire would be secured by a Tension Wire Mount Assembly .
The Tension Wire Mount Assembly  is spring loaded to...