Oil pump

Abstract

Certain preferred embodiments of the present invention provide an oil pump which is both light as well as compact. Accordingly, certain presently preferred embodiments disclose an oil pump having a housing comprising aluminum, and at least one mobile molded part therein. The mobile molded part being at least partially made from a sinterable composition comprising at least one austenitic iron-based alloy powder. The mobile molded part also has a heat expansion coefficient, which amounts to at least 60% of the heat expansion coefficient for the oil pump housing.

1 - 7 . (canceled)  
   
   
       8 . An oil pump comprising: 
 a housing comprising aluminum, said housing having a first heat expansion coefficient; and    at least one molded part comprising at least one sinterable composition, 
 said sinterable composition comprising at least one austenitic iron-based alloy powder, and said molded part further having a second heat expansion coefficient at least 60% of said first heat expansion coefficient.  
   
   
   
       9 . The oil pump according to  claim 8 , wherein said second heat expansion coefficient is at least 70% of said first heat expansion coefficient.  
   
   
       10 . The oil pump according to  claim 8 , wherein said second heat expansion coefficient is at least 74% of said first heat expansion coefficient.  
   
   
       11 . The oil pump according to  claim 8 , wherein said at least one molded part further comprises aluminum-containing alloy powder.  
   
   
       12 . The oil pump according to  claim 8 , wherein said austenitic iron-based alloy powder comprises: 
 iron; and    0.005 to 0.04 weight percent carbon, 0.1 to 1.5 weight percent silicon, 8 to 18 weight percent nickel, 0 to 25 weight percent chromium, 1 to 4 weight percent molybdenum, and 0.05 to 1 weight percent manganese, based on the weight of the austenitic iron-based alloy powder.    
   
   
       13 . The oil pump according to  claim 8 , wherein said at least one molded part further comprises cast aluminum, cast iron, sintered cast iron, steel, or combinations thereof.  
   
   
       14 . The sinterable composition of  claim 8 , further comprising from 0.2 to 5 weight percent of at least one lubricant, based on the weight of said sinterable composition.  
   
   
       15 . The sinterable composition of  claim 14 , wherein said at least one lubricant is MoS 2 , WS 2 , BN, MnS, or carbon.  
   
   
       16 . The sinterable composition of  claim 8 , further comprising polyvinyl acetate, an amide wax, or combinations thereof.  
   
   
       17 . The sinterable composition of  claim 16 , wherein the amide wax comprises ethylene-bisstearoylamide, shellac, polyalkylene oxide, polyglycol, or combinations thereof.  
   
   
       18 . The oil pump according to  claim 8 , wherein said at least one molded part has a hardness of at least 100 HB, according to DIN EN 24 498-1.  
   
   
       19 . The oil pump according to  claim 8 , wherein said at least one molded part has a hardness of at least 120 HB, according to DIN EN 24 498-1.  
   
   
       20 . The oil pump according to  claim 8 , wherein said at least one molded part has a hardness of at least 130 HB, according to DIN EN 24 498-1.  
   
   
       21 . The oil pump according to  claim 8 , wherein said at least one molded part has a hardness of at least 140 HB, according to DIN EN 24 498-1.  
   
   
       22 . The oil pump according to  claim 8 , wherein said second heat expansion coefficient is from about 15 to about 21 ppm.  
   
   
       23 . The oil pump according to  claim 8 , wherein said second heat expansion coefficient is from about 16 to about 19 ppm.  
   
   
       24 . The oil pump according to  claim 8 , wherein said at least one molded part comprises at least one rotor arranged on a shaft, and the axial distance between said rotor and said housing is less than 50 μm.  
   
   
       25 . The oil pump according to  claim 8 , wherein said at least one molded part comprises at least one rotor arranged on a shaft, and the axial distance between said rotor and said housing is less than 40 μm.  
   
   
       26 . A method for producing at least one molded part, comprising: 
 providing a sinterable composition, having at least one austenitic iron-based alloy powder, to a mold;    pressing said sinterable composition under a pressure of at least 500 MPa to obtain a density of at least 6.5 g/cm 3 , according to DIN ISO 2738; and    sintering said sinterable composition at a temperature of at least 1,000° C. in a gaseous atmosphere comprising at least one of nitrogen and hydrogen.    
   
   
       27 . The method of  claim 26 , wherein the ratio of said nitrogen to said hydrogen is at least 66:33.  
   
   
       28 . The method of  claim 26 , wherein the ratio of said nitrogen to said hydrogen is at least 95:5.  
   
   
       29 . The method according to  claim 26 , further comprising: 
 pressing said sinterable composition at a pressure of at least 600 MPa to a density of at least 6.7 g/cm 3 , said density being in accordance with DIN ISO 2738.    
   
   
       30 . The method according to  claim 26 , further comprising: 
 pressing said sinterable composition at a pressure of at least 750 MPa to a density of at least 6.7 g/cm 3 , said density being in accordance with DIN ISO 2738.    
   
   
       31 . The method of  claim 26 , wherein said sinterable composition further comprises aluminum-containing alloy powder.  
   
   
       32 . The method of  claim 26 , wherein said austenitic iron-based alloy powder comprises: 
 iron; and    0.005 to 0.04 weight percent carbon, 0.1 to 1. weight percent silicon, 8 to 18 weight percent nickel, 0 to 25 weight percent chromium, 1 to 4 weight percent molybdenum, and 0.05 to 1 weight percent manganese, based on the weight of the austenitic iron-based alloy powder.    
   
   
       33 . The method of  claim 26 , wherein said sinterable composition further comprises from 0.2 to 5 weight percent of at least one lubricant, based on the weight of said sinterable composition.  
   
   
       34 . The method of  claim 33 , wherein said at least one lubricant is MoS 2 , WS 2 , BN, MnS, or carbon.  
   
   
       35 . The method of  claim 26 , wherein said sinterable composition further comprises polyvinyl acetate, an amide wax, or combinations thereof.  
   
   
       36 . The method of  claim 35 , wherein the amide wax comprises ethylene-bisstearoylamide, shellac, polyalkylene oxide, polyglycol, or combinations thereof.  
   
   
       37 . A molded part made by the method of  claim 26 .  
   
   
       38 . A molded part made by the method of  claim 29 .  
   
   
       39 . An oil pump comprising: 
 a housing comprising aluminum, said housing having a first heat expansion coefficient; and    at least one molded part comprising at least one sinterable austenitic iron-based alloy, said alloy having a second heat expansion coefficient at least 60% of said first heat expansion coefficient; and    said at least one molded part being made by the method comprising providing a sinterable composition, comprising at least one austenitic iron-based alloy, to a mold;    pressing said sinterable composition under a pressure of at least 500 MPa with a density, according to DIN ISO 2738, amounts to at least 6.5 g/cm 3 , and    sintering said sinterable composition at a temperature of at least 1,000° C. in a gaseous atmosphere comprising at least one of nitrogen and hydrogen.    
   
   
       40 . The oil pump according to  claim 39 , wherein said at least one molded part has a hardness of at least 100 HB, according to DIN EN 24 498-1.  
   
   
       41 . The oil pump according to  claim 39 , wherein said at least one molded part has a hardness of at least 120 HB, according to 3 EN 24 498-1.  
   
   
       42 . The oil pump according to  claim 39 , wherein said at least one molded part has a hardness of at least 130 HB, according to DIN EN 24 498-1.  
   
   
       43 . The oil pump according to  claim 39 , wherein said at least one molded part has a hardness of at least 140 HB, according to DIN EN 24 498-1.  
   
   
       44 . The oil pump according to  claim 39 , wherein said second heat expansion coefficient is at least 70% of said first heat expansion coefficient.  
   
   
       45 . The oil pump according to  claim 39 , wherein said second heat expansion coefficient is at least 74% of said first heat expansion coefficient.  
   
   
       46 . The oil pump according to  claim 39 , wherein said second heat expansion coefficient is from about 15 to about 21 ppm.  
   
   
       47 . The oil pump according to  claim 39 , wherein said at least one molded part comprises at least one rotor arranged on a shaft, and the axial distance between said rotor and said housing is less than 40 μm.  
   
   
       48 . The oil pump according to  claim 39 , wherein said at least one molded part comprises at least one rotor arranged on a shaft, and the axial distance between said rotor and said housing is less than 50 μm.  
   
   
       49 . The method according to  claim 39 , further comprising: 
 pressing said sinterable composition at a pressure of at least 600 MPa to a density of at least 6.7 g/cm 3 , said density being in accordance with DIN ISO 2738.    
   
   
       50 . The method according to  claim 39 , further comprising: 
 pressing said sinterable composition at a pressure of at least 750 MPa to a density of at least 6.7 g/cm 3 , said density being in accordance with DIN ISO 2738.    
   
   
       51 . The method of  claim 39 , wherein the ratio of said nitrogen to said hydrogen is at least 66:33.  
   
   
       52 . The method of  claim 39 , wherein the ratio of said nitrogen to said hydrogen is at least 95:5.