Coupling element for an eccentric screw rotor
A coupling element for connecting a helix-shaped eccentric screw pump rotor to a drive shaft, with a drive shaft receiving portion and a rotor connecting portion arranged at an opposite end of the coupling element from the drive shaft receiving portion, the rotor connecting portion is constituted as a hollow cylinder for receiving a rotor end of the screw pump rotor, wherein the hollow cylinder has at least two inner circumferential surfaces which are complementary to the rotor and have a radius which is fixed with respect to the cross-sectional center of the hollow cylinder.
1. A coupling element for connecting a helix-shaped eccentric screw pump rotor to a drive shaft, comprising:
a drive shaft receiving portion, and
a rotor connecting portion arranged at an opposite end of the coupling element from the drive shaft receiving portion,
the rotor connecting portion is constituted as a hollow cylinder for receiving a rotor end of the screw pump rotor,
wherein the hollow cylinder has at least two inner circumferential surfaces which are complementary to the rotor and have a radius which is fixed with respect to the cross-sectional centre of the hollow cylinder,
wherein at least one surface section with a larger inner radius than the radius is present between the inner circumferential surfaces.
2. The coupling element according to claim 1 , wherein the radius of the inner circumferential surfaces is the smallest radius of the inner surfaces of the hollow cylinder.
3. The coupling element according to claim 1 , wherein at least one radial bore is provided in a casing of the hollow cylinder for receiving a securing element.
4. The coupling element according to claim 1 , wherein the hollow cylinder is divided in the longitudinal direction.
5. The coupling element according to claim 1 , wherein its drive shaft receiving portion is constituted as a cardan hinge receptacle.
6. The coupling element according to claim 1 , wherein the rotor connecting portion is a casting without additional machining.
7. The coupling element according to claim 1 , wherein the radius of the inner circumferential surfaces is the smallest radius of the inner surfaces of the hollow cylinder.
8. The coupling element according to claim 1 , wherein at least one radial bore is provided in a casing of the hollow cylinder for receiving a securing element.
9. The coupling element according to claim 1 , wherein the hollow cylinder is divided in the longitudinal direction.
10. The coupling element according to claim 1 , wherein the drive shaft receiving portion is constituted as a cardan hinge receptacle.
11. The coupling element according to claim 1 , wherein the rotor connecting portion is a casting without additional machining.
12. A rotor connecting device, comprising:
a helix-shaped eccentric screw pump rotor, and
a coupling element for connecting the helix-shaped eccentric screw pump rotor to a drive shaft, having a drive shaft receiving portion and a rotor connecting portion arranged at an opposite end of the coupling element from the drive shaft receiving portion,
the rotor connecting portion is constituted as a hollow cylinder for receiving a rotor end of the screw pump rotor,
wherein the hollow cylinder has at least two inner circumferential surfaces which are complementary to the rotor and have a radius which is fixed with respect to the cross-sectional centre of the hollow cylinder
wherein at least one surface section with a larger inner radius than the radius is present between the inner circumferential surfaces.
13. The rotor connecting device according to claim 12 wherein a helix shape of the rotor is uniform over its entire length.
14. The rotor connecting device according to claim 13 , wherein the rotor end rests only on the inner circumferential surfaces of the coupling element.
15. The rotor connecting device according to claim 12 , wherein the rotor end rests only on the inner circumferential surfaces of the coupling element.