Electric gerotor pump and method for producing same

Patent metadata

Field	Value
Publication number	US-11092153-B2
Application number	US-201716344144-A
Country	US
Kind code	B2
Filing date	Oct 5, 2017
Priority date	Nov 7, 2016
Publication date	Aug 17, 2021
Grant date	Aug 17, 2021

Abstract

An electrically driven gerotor pump has a gerotor which comprises a stationary outer gerotor element with an inner toothing that is axially delimited by two chamber walls, wherein each chamber-forming foot section of the inner toothing is paired with a pressure valve which is connected to the outlet. The gerotor also comprises an inner gerotor element with an outer toothing which is guided in the outer gerotor element in a circumferential manner on an eccentric section of the shaft and is mounted in, a rotatable manner so as to mesh with the inner toothing.

First claim

The invention claimed is:

1. An electrically driven gerotor pump comprising:
a pump housing in which a shaft is rotatably mounted and in which a gerotor, an inlet and an outlet are included;
an electric drive with a motor stator and a motor rotor, which is connected to the shaft and which rotationally drives the gerotor;
wherein
the gerotor comprises a stationary outer gerotor element with a plurality of internal teeth which is axially delimited by two chamber walls, each chamber-forming root portion of the internal teeth having associated therewith a pressure valve communicating with the outlet;
an inner gerotor element with a plurality of external teeth which is circumferentially guided and rotatably mounted on an eccentric portion of the shaft in the outer stationary gerotor element so as to meshingly engage the internal teeth;
and a link between the inlet and the chamber-forming root portions of the internal teeth of the stationary outer gerotor element extends through a free end of the shaft, a control slot in an eccentric extension and a radial branch to root portions of the external teeth in the inner gerotor element.

2. The electrically driven gerotor pump according to 1 , wherein
the eccentric portion of the shaft on which the inner gerotor element is circumferentially guided and rotatably mounted is formed as an eccentric extension on a free end of the shaft.

3. The electrically driven gerotor pump according to 2 , wherein
a bearing of the shaft is arranged in the pump housing in a single axial shaft portion and comprises at least two rows of roller bodies.

4. The electrically driven gerotor pump according to claim 1 , wherein
a chamber wall closes an open axial end of the pump housing and includes orifices of the inlet and outlet.

5. The electrically driven gerotor pump according to claim 1 , wherein
the pressure valves are formed by radial opening slots in the stationary outer gerotor element which are covered with respect to an annular outlet chamber around the outer stationary gerotor element by clasp-like bent sheet-metal parts with a turnaround section.

6. The electrically driven gerotor pump according to claim 1 , wherein
the chamber walls have a surface structure with a regular or irregular pattern applied at a depth of 1 to 2 μm on the front faces facing the gerotor.

7. The electrically driven gerotor pump according to claim 1 , wherein
on inner faces the pump housing has axial portions with cylindrical lateral surfaces, which fit in a fixing manner to a cylindrical outer circumferential portion of a shaft seal, a bearing of the shaft, at least one of the two chamber walls and the stationary outer gerotor element.

8. A method for producing electrically driven gerotor pump, comprising the steps of:
press-fitting, in this axial order, a shaft seal, a shaft bearing including a shaft, a first front-face chamber wall and a stationary outer gerotor element into a pump housing having, an inlet and an outlet; wherein the stationary outer gerotor element comprises a plurality of internal teeth which are axially delimited by two chamber walls, each chamber-forming root portion of the internal teeth having associated therewith a pressure valve communicating with the outlet;
intermediately or subsequently sliding an eccentric extension of the shaft into a press-fitted stationary bearing of an inner gerotor element; the inner gerotor element with a plurality of external teeth which is circumferentially guided and rotatably mounted on an eccentric portion of the shaft in the stationary outer gerotor element so as to meshingly engage the internal teeth, and a link between the inlet and the chamber-forming root portions of the internal teeth of the stationary outer gerotor element extends through a free end of the shaft, a control slot in an eccentric extension and a radial branch to root portions of the external teeth in the inner gerotor element;
fixing a second front-face chamber wall in the pump housing by press-fitting or welding;
intermediately or subsequently press-fitting the other end of the shaft into a motor rotor for rotationally driving the gerotor; and
inserting and fixing a motor stator with motor electronics as well as a motor cover.

Assignees

• Nidec Gpm Gmbh

Inventors

• Pawellek Franz
• Nickel Conrad

Classifications

• F04C11/008

  Enclosed motor pump units · CPC title

• F04C2240/51

  for cantilever assemblies · CPC title

• F04C2230/60

  Assembly methods · CPC title

• F04C2240/40

  Electric motor · CPC title

• F04C2/103 Primary

  one member having simultaneously a rotational movement about its own axis and an orbital movement · CPC title