	US 7,458,792 B2
	Sintered metal rotor of a rotary piston pump
Peter Grahle, Feldbrunnen (Switzerland); Peter Haldemann, Grenchen (Switzerland); Walter Nünlist, Olten (Switzerland); Heinz Rhyn, Grossaffoltern (Switzerland); Albert Friesen, Mönchengladbach (Germany); and Stanislaus Russ, Mönchengladbach (Germany)
Assigned to Mahle Motorkomponenten Schweiz AG, Grenchen (Switzerland); and Pierburg GmbH, Neuss (Germany)
Appl. No. 10/541,016 PCT Filed Jun. 16, 2004, PCT No. PCT/DE2004/001239 § 371(c)(1), (2), (4) Date Jun. 28, 2005, PCT Pub. No. WO2005/001293, PCT Pub. Date Jan. 06, 2005.
Claims priority of application No. 103 29 495 (DE), filed on Jun. 30, 2003.
Prior Publication US 2006/0165545 A1, Jul. 27, 2006
Int. Cl. F01C 21/00 (2006.01); F03C 2/00 (2006.01)

U.S. Cl. 418—179

13 Claims

1. A method for producing a sintered metal rotor of a rotary piston pump, in particular a rotary piston pump for generating a vacuum of a vacuum brake booster of a motor vehicle, where the brake booster can be connected to a vacuum pump intake connection, with a pot-shaped base body (1) and a bearing journal element which protrudes centrally from the bottom of this base body (1) from a cylindrical foot area coming directly out of the bottom and a connecting claw section (2) to be connected to it for a coupling element to be attached, comprising the features

the connecting claw section (2) is designed in the form of two protruding individual webs (3),

the individual webs (3) are diametrically opposed in the outside circumferential area of the cylindrical base section in an area limited to max. 100° at the circumference and radially to max. 25% of the diameter of the cylindrical base section, and

assigning separate rams to the individual webs (3) according to cross section of the web and providing each ram with a separate pressure acting on them in a sintering compression mold for producing the sintered rotor; and

wherein the produced rotor has the structure of a one piece, press-sintered rotor with differently compressed regions, whereby the individual webs (3) are compressed to a sufficient degree for the material stability required in each region, and the sintering pressure is sufficient to achieve a material density of 6.8 to 7.4 g/cm³.