An oil pump in a motor vehicle, having a case and an electric motor mounted in the case. The electric motor drives a pump stage which is likewise mounted in the case. The oil pump is an axial flow centrifugal pump.
1. An oil pump in a motor vehicle, comprising:
a housing;
an electric motor arranged in the housing;
a pump stage arranged in the housing and configured to be driven by the electric motor, the pump stage comprising:
a vane wheel;
a plurality of vanes arranged on the vane wheel such that at least one free region of about 25%-70% in circumferential direction over an entire axial length of the vane wheel is formed between respective ends of two adjacent vanes on a circumference of the vane wheel,
wherein the vanes are rectilinear at their respective ends opposite a direction of rotation, and
wherein the respective rectilinear ends extend from a hub at an incline counter to the direction of rotation, and
wherein the oil pump is an axial-type rotatory pump;
a tubular outer ring surrounding the vane wheel, having an inlet nozzle; and
wherein the inlet nozzle has an input having a first diameter and an outlet having a second diameter that is smaller than the first diameter.
2. The oil pump as claimed in claim 1 , wherein the free regions on the circumference of the vane wheel between two vanes account for about 30% 50% of the circumference of the vane wheel.
3. The oil pump as claimed in claim 1 , wherein the vane wheel has two to four vanes.
4. The oil pump as claimed in claim 1 , wherein a length of the vanes in the direction of rotation is at least equal to a radial width b of the vanes.
5. The oil pump as claimed in claim 1 , wherein a radial width b of the vanes is constant over their length.
6. The oil pump as claimed in claim 1 , wherein the vanes are rounded at their end pointing in the direction of rotation.
7. The oil pump as claimed in claim 2 , wherein the free regions on the circumference of the vane wheel between two vanes account for a total of about 38% 40%, of the circumference of the vane wheel.
8. The oil pump as claimed in claim 1 , wherein the hub of the vane wheel is dome-shaped.
9. The oil pump as claimed in claim 1 ,
wherein the vanes are curved with a first arc at their ends respective ends in a direction of rotation,
wherein the respective ends are connected by a second arc portion,
wherein the first arc and the second arc are different.
10. The oil pump as claimed in claim 9 , wherein the hub of the vane wheel is dome-shaped.
11. The oil pump as claimed in claim 6 , wherein the rounded end has a radius whose center is arranged in the vane in relation to a radial width of the vane.
12. The oil pump as claimed in claim 6 , wherein the rounded end has a first convex portion proximate to the hub and a second concave portion.
13. The oil pump as claimed in claim 1 , wherein the inlet nozzle has a partially arcuate portion leading from an input area to the tubular outer ring.
14. The oil pump as claimed in claim 1 , wherein the plurality of vanes are arranged at a distance from the an outlet of the inlet nozzle.