ELECTRIC GEAR PUMP

• US 20190323500A1
• Filed: 12/14/2017
• Published: 10/24/2019
• Est. Priority Date: 12/22/2016
• Status: Abandoned Application

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Medoro, Nello
• Application Number:
  US16/472,991
• Publication Number:
  US 20190323500A1
• Time in Patent Office: Days
• CPC Class Codes: F04C 15/008 Prime movers
• CPC Class Codes: F04C 2/102 the two members rotating simultaneously around their respective axes

Abstract

An electric gear pump comprising a gerotor that may rotate about an axis of rotation A, comprising an external spur rotor and an internal spur rotor arranged outside the external spur rotor; a stator having electrical windings arranged outside the internal spur rotor; at least one magnet at least partially housed in the internal spur rotor in such a way as to cause the gerotor to rotate when the electrical windings of the stator are supplied with current; in which the internal spur rotor comprises a cylindrical external surface centred on the axis of rotation A; the magnet comprises an external surface separated from the external surface of the internal spur rotor; the external surface of the magnet is shaped in such a way as to define a constant radial distance d between the magnet and the corresponding portion of the external surface of the internal spur rotor.

Claims

1. An electric gear pump (4) comprising:

a gerotor (9) configured to rotate about an axis of rotation (A), the gerotor comprising an external spur rotor (21) and an internal spur rotor (22) arranged outside the external spur rotor (21);

a stator (25) having electrical windings (26) arranged outside the internal spur rotor (22);

at least one magnet (23) at least partially housed in the internal spur rotor (22) in such a way as to cause the gerotor (9) to rotate when the electrical windings (26) of the stator (25) are supplied with current;

wherein;

the internal spur rotor (22) comprises a cylindrical external surface (29) centered on the axis of rotation (A);

the magnet (23) comprises an external surface (30) separated from the external surface of the internal spur rotor (22); and

the external surface (30) of the magnet (23) is shaped in such a way as to define a constant radial distance (d) between the magnet (23) and the corresponding portion of the external surface (29) of the internal spur rotor (22).

2. A pump as claimed in claim 1, wherein the pump (4) comprises a support base (24) for the gerotor (9) and a closure cover (27);

wherein the internal spur rotor (22) comprises a lower surface (31) for coupling with the base (24) and an upper surface (32) for coupling with the cover (27), and wherein the internal spur rotor (22) comprises at least one seat (33) for housing the magnet (23) on the lower surface (31) or on the upper surface (32).

3. The pump as claimed in claim 2, wherein the seat (33) is a channel with a shape corresponding to the magnet (23).

4. The pump as claimed in claim 2, wherein, when inserted in the seat (33), the magnet (23) is flush with the lower surface (31) or the upper surface (32) of the internal spur rotor (22).

5. The pump as claimed in claim 4, wherein the pump comprises at least two magnets (23) and the internal spur rotor (22) comprises at least one lower seat (33) on the lower surface (31) and at least one upper seat (33) on the upper surface (32).

6. The pump as claimed in claim 5, wherein the lower and upper seats (33) are aligned along an axis parallel to the axis of rotation A.

7. The pump as claimed in claim 5, wherein a distance between the lower and upper seats (33) is less than a thickness of the magnet (23) measured along an axis parallel to the axis of rotation A.

8. The pump as claimed in claim 1, wherein the magnet (23) is in the form of a ring.

9. The pump as claimed in claim 8, in which wherein the magnet (23) in the form of a ring is made as a single piece.

10. A pump assembly for supplying fuel from a tank (2) to an internal combustion engine (3);

the pump assembly (1) comprising, in series, a low-pressure electric gear pump (4) and a high-pressure pump (5);

wherein the low-pressure electric gear pump (4) is configured according to claim 1.

11. The pump as claimed in claim 8, wherein the magnet (23) in the form of a ring is made as a plurality of adjacent parts.