One-piece, force-locking compensating coupling made from plastic
The compensating coupling presented here can inexpensively be produced by injection moulding. Both axial and radial shifts as well as angular errors can be compensated for to a significant extent. In contrast to conventional plastic couplings, higher torques can be transferred. Its connection to the respective shafts is realized by an innovative clamping hub that secures the required traction.
Production of multi-piece couplings is expensive and time-consuming. There are one-piece compensating couplings that can be produced inexpensively, however these are only suitable for low tourques. Especially the connection to the shaft can be a critical point. For the coupling to be able to transfer a high as possible tourque, the connection to the shaft has to offer the needed traction. Thus, there is a lack for inexpensive plastic compensating couplings with an appropriate shaft-coupling for medium tourques.
The Figure on the right, illustrates the newly designed plastic coupling (Fig. 1). This one-piece design can easily be produced by injection moulding (s. Fig. 2 B).
A friction-free transmission of tourques to the shaft, can for this coupling easily be realized by a clamping hub in combination with a contact element, for example a coating that increases the friction coefficient (s. Fig. 2 A).
Fig. 2: A) Clamping hub (1) that consists of a clamp (2) that eccentricly fits on the coupling body (4) and is tightened by a screw (3) to clamp onto the shaft. A coated contact element (5) increases the friction coefficient. B) Production of a compensating coupling by injection molding using three mold tools (7) that comprise shapes for the interspaces. (Source: Prof. Dr. Sven Lippardt)
Transmission of medium tourques for which conventional plastic couplings are not suitable, but metal couplings would be overbuild.
CAD-Drawings are available and injection moulding tools have been designed. Transmittable tourques have been determined by flexural strength tests with test rods and simulations of the coupling under load by the finite-elemente-method (see table).