Toothing system for a gerotor pump, and method for geometric determination thereof

Patent metadata

Field	Value
Publication number	US-11566617-B2
Application number	US-201816969840-A
Country	US
Kind code	B2
Filing date	Nov 22, 2018
Priority date	Feb 20, 2018
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

A toothing for a gerotor pump comprises a plurality of outer teeth (10) at a gerotor inner element (1) and a plurality of inner teeth (20) greater by one at a gerotor outer element (2), wherein a centre (M1) of the gerotor inner element (1) is offset from a centre (M2) of the gerotor outer element (2) by an eccentricity (e), the outer teeth (10) thereby meshing with the inner teeth (20). A contour of the outer teeth (10) at the gerotor inner element (1) is essentially defined by a curve of a single ellipse from a tooth tip (11) continuously via tooth flanks (13) to a transition radius (14) towards a tooth space or a tooth root (12); wherein the principal axis of the ellipse is arranged radially to the gerotor inner element (1) and the centre of the ellipse determines a radius (Rmin) at the gerotor inner element (1) which corresponds to the maximum meshing depth of the gerotor outer element (2) between the outer teeth (10) at the meshing.

First claim

The invention claimed is:

1. A toothing for a gerotor pump comprising:
a plurality of outer teeth at a gerotor inner element; and
a plurality of inner teeth greater by one at a gerotor outer element, wherein a center of the gerotor inner element is offset from a center of the gerotor outer element by an eccentricity such that the outer teeth thereby mesh with the inner teeth, and wherein a contour of the outer teeth at the gerotor inner element is defined by a curve of a single ellipse from a tooth tip continuously via tooth flanks to a transition radius towards a tooth space or a tooth root, and further wherein a principal axis of the ellipse is arranged radially to the gerotor inner element and ellipse determines a radius at the gerotor inner element which corresponds to a maximum meshing depth of the gerotor outer elements between the outer teeth during the meshing, and wherein, in rotation of the gerotor outer element, a root clearance is defined at an apex between two of the outer teeth by the radius of the maximum meshing depth and the eccentricity.

2. The toothing for a gerotor pump according to claim 1 , wherein the contour of the outer teeth extends radially and is defined by the eccentricity multiplied by a factor of 4.

3. The toothing for a gerotor pump according to claim 1 , wherein the principal axis of the ellipse is defined by the eccentricity multiplied by a factor of 4.

4. The toothing for a gerotor pump according to claim 1 , wherein minor axis of the ellipse is orthogonal to the principal axis and is defined by the eccentricity multiplied by a factor between 0.5 to 2.5.

5. The toothing for a gerotor pump according to claim 1 , wherein a contour of the gerotor inner element is respectively formed in a concave shape between two outer teeth.

6. The toothing for a gerotor pump according to claim 1 , wherein a contour of the gerotor inner element is respectively formed in a concave shape between two outer teeth, and wherein the concave contour includes the root clearance defined by the radius of the maximum engagement of the gerotor outer element, the maximum engagement of the gerotor outer element defined by an extent of the eccentricity multiplied by a factor between 0.1 and 0.15.

7. The toothing for a gerotor pump according to claim 1 , wherein a contour of the inner teeth of the gerotor outer element results from an intersection of an envelope of a family of curves which is set along a course of movement of the gerotor pump through the contour of the outer teeth of the gerotor inner element.

8. The toothing for a gerotor pump according to claim 1 , wherein the gerotor inner element comprises a number of at least five outer teeth.

9. The toothing for a gerotor pump according to claim 1 , wherein the gerotor outer element is rotably supported in the gerotor pump and is rotably dragged along via the meshing by a rotary drive motion of the gerotor inner element.

10. The toothing for gerotor pump according to claim 1 , wherein the gerotor pump is adapted to convey lubrication oil to a combustion machine.

11. The toothing for gerotor pump according to claim 1 , wherein the gerotor pump is adapted to convey transmission oil.

12. The toothing for gerotor pump according to claim 1 , wherein the gerotor pump is adapted to convey hydraulic oil.

13. A method for geometric determination of a toothing for a gerotor pump which comprises a plurality of outer teeth at a gerotor inner element and a plurality of inner teeth greater by one at a gerotor outer element, wherein a center of the gerotor inner element is offset from a center of the gerotor outer element by an eccentricity such that the outer teeth thereby mesh with the inner teeth, the method comprising:
setting one single ellipse, a principal axis of which is arranged radially to the gerotor inner element as well as setting a dispersed radial arrangement of such ellipses according to the plurality of outer teeth;
defining contour sections of the outer teeth along a curve of each ellipse;
defining contour sections between the outer teeth along a radius that is determined by a center of each ellipse, wherein the radius at the gerotor inner element is corresponding to a maximum meshing depth of the gerotor outer element between the outer teeth at the meshing;
defining, in rotation of the gerotor outer element, a root clearance, at an apex between two of the outer teeth, by the radius of the maximum meshing depth and the eccentricity; and
defining transition radii which connect the contour sections of the outer teeth with the contour sections between the outer teeth.

14. The method for the geometrical determination of a toothing for a gerotor pump according to claim 13 , further comprising:
setting a radial extension of the elliptical contour of the plurality of outer teeth as a function of the eccentricity.

15. The method for the geometrical determination of a toothing for a gerotor pump according to claim 13 , further comprising:
setting a dimension of the principal axis of the ellipse as a function of the eccentricity.

16. The method for the geometrical determination of a toothing for a gerotor pump according to claim 13 , further comprising:
setting a dimension of an orthogonal minor axis of the ellipse as a function of the eccentricity.

17. The method for the geometrical determination of a toothing for a gerotor pump according to claim 13 , further comprising:
defining concave recesses in the contour sections between the outer teeth and determining a recess depth to the radius that is determined by a center of the ellipse as a function of the eccentricity.

18. The method for the geometrical determination of a toothing for a gerotor pump according to claim 13 , further comprising:
defining a contour of the inner teeth of the gerotor outer element via an intersection of an ellipse curve which is defined by the contour of the outer teeth of the gerotor inner element.

Assignees

• Nidec Gpm Gmbh

Inventors

• Blechschmidt Andreas

Classifications

• F01C1/084

  Toothed wheels · CPC title

• F04C2/084 Primary

  Toothed wheels · CPC title

• F04C2/102

  the two members rotating simultaneously around their respective axes · CPC title