Patent Publication Number: US-2009226123-A1

Title: Bearing Bush Assembly, Bearing and Semicircular Bearing Shell Half

Description:
The invention relates to a bearing shell assembly, a bearing, and a semicylindrical bearing shell half. The invention also relates to a main crankshaft bearing and a mass balance transmission bearing. 
     U.S. Pat. No. 2,678,767 describes a bearing of the small connecting rod eye comprising two bushings set at a spacing from each other between which an oil duct is formed. Bearing shells are used less as bearings in large connecting rod eyes. 
     The crankshaft of a car or truck engine is mounted in so-called main bearings through which the connecting rod bearings are supplied with oil. The main bearings are formed with and without a collar. In order to guarantee this oil supply, the main bearing has an upper bearing shell having at least one oil bore and an oil groove extending essentially around the entire inner surface. The corresponding crankshaft pin has a radial oil bore through which the oil in the upper bearing shell is passed and provided to the connecting rod bearing. The upper bearing shell is made with and without a collar. Collar bearing shells of this type are known from U.S. Pat. No. 4,845,817, for example. As a rule, however, these bearing shells are so-called composite collar bearing shells in which the end disk engage on the bearing shell in a movable fashion. 
     Bearing shells with and without collars and with an oil groove are also used in so-called mass balance transmission bearings. 
     The requirements for bearing shells of this type relate to the size of the flow cross section of the oil groove, among other things. In order to be able to provide the largest amount of oil possible, a wide and deep oil groove is desirable. However, its depth is limited by the need for strength of the bearing shell. Due to the thinness of the material at the base of the groove, the back of the bearing shell may not rest completely in the bearing support. If the oil grooves are too wide, the remaining support area of the bearing shell is again too small. 
     Another disadvantage of conventional bearing shells lies in the fact that the oil groove must be produced by machining, that at least one oil bore must be formed, and that the material that is removed must be disposed of as waste. In producing the oil groove as well as in producing the oil bore, small filings (flakes) result. These filings are extremely disruptive to the production process and must be removed using expensive washing processes. 
     Therefore, the object of the invention is to provide a bearing shell assembly as well as a bearing, in particular a primary bearing for a crankshaft, and a mass balance transmission bearing that may be produced in a simple manner, with the flow cross section of the oil groove being greater than that of conventional bearing shells and the size of the support region remaining the same. The object of the invention is also to provide bearing shell halves for a bearing shell assembly of this kind. 
     This object is attained with a bearing shell assembly with a bearing length B 1  and having two semicylindrical bearing shell halves each with a width B 2 &lt;B 1 /2 set at an axial spacing from each other, with an oil duct extending angularly of the bearing shell halves being formed between the bearing shell halves. 
     The invention preferably refers to bearing shells with an outside diameter of 20 mm to 150 mm. 
     The length B 1  of the bearing shell assembly includes the widths of both bearing shell halves and the width of the oil duct formed between the two bearing shell halves. This length B 1  is determined by the width B 3  of the bearing shell support or bearing bore in the bearing housing. In the case of bearing shell halves with axial bearing parts located on the edge, the bearing shell halves are located opposite the bearing bore, such that B 3 &lt;B 1 . In general, B 3 ≦B 1 . 
     An oil duct is formed between the two bearing shell halves; according to the invention, the entire thickness of the bearing shell is available for its radial depth. If the widths B 2  of the two bearing shell halves correspond to the width of the support surface portion of conventional individual bearing shells with an oil groove, the oil duct has a greater flow cross section than the oil groove in the conventional bearing shell. Conversely, if the oil duct has the same flow cross section as conventional bearing shells, the amount of supporting surface may be increased by a correspondingly greater width of the bearing shell halves. 
     The width of the oil duct and thus the flow cross section may be selected by the user by establishing the axial spacing between the bearing shell halves by selecting the width B 2 . 
     The expensive formation of the oil groove is eliminated, no filings are produced, and at the same time a considerable amount of bearing shell material is saved. 
     Preferably, each bearing shell has an axial bearing part on its end edge. While in conventional collar bearing shells the mass between the two axial bearing parts is fixed, it is now possible for this mass to be freely selected. The bearing shell halves may thus be used in a variable fashion. 
     Preferably, the two bearing shell halves are identical.  This simplifies their manufacture considerably. 
     Preferably, the oil duct extends over the entire angular length of the baring shell halves. The two bearing shell halves are not in contact with one another. 
     A particular use of at least two semicylindrical bearing shell halves is provided for oil-lubricated bearings, in particular in vehicle motors. 
     The oil-lubricated bearing with one first and one second bearing shell that are adjacent to one another on their partial surfaces is characterized in that at least one of the two bearing shells has been divided in two and is composed of two semicylindrical bearing shell halves that are mounted at a spacing from each other axially of the bearing, with an oil duct extending angularly being formed between the bearing shell halves. 
     The main crankshaft bearing according to the invention having a bearing bore with the width B 3  and a bearing assembly with a length B 1  and including an upper shell and a lower shell placed in the bearing housing, with the bearing housing having at least one oil supply to the upper shell, is characterized in that the upper shell is divided in two and is formed by two semicylindrical bearing shell halves that are spaced from each other axially of the bearing, with an oil duct extending angularly into which the oil supply empties being formed between the bearing shell halves. 
     The bearing shell halves of the main crankshaft bearing and the mass balance transmission bearing may optionally be provided with axial bearing parts, or not. 
     A semicylindrical bearing shell half with a width B 2  having an outside diameter D as well as partial surfaces is characterized in that the bearing shell half may be used in conjunction with a second semicylindrical bearing shell half with a width B 2  to form a bearing shell assembly with a bearing length B 1 , with the two bearing shell halves being spaced from each other, with an oil groove that extends angularly of the bearing shell halves being between the bearing shell halves, and in that the following applies to the ratio V between the outside diameter D of the bearing shell in mm and the width B 2  of the bearing shell half in mm: 
       2.5≦V≦6 for 20≦D≦24 
       2.4≦V≦10 for 24≦D≦40 
       4≦V≦8.5 for 40&lt;D≦60 
       5≦V≦20 for 60≦D≦100 
       4.8≦V≦20 for 100&lt;D≦150 
     Preferably, the semicylindrical bearing shell half has at least one retaining formation in the partial surface that projects opposite the outer surface of the bearing shell half. According to a special embodiment, one retaining formation each is provided in each partial surface. The provision of at least one retaining formation each in each partial surface has the advantage that a high degree of precision in alignment is guaranteed and axial slippage in the bearing support is prevented. 
     Preferably, the semicylindrical bearing shell half is characterized by an axial bearing part that is arranged on one edge of the bearing shell half. 
     The bearing shell halves are distinguished by a low level of tilt by the partial surfaces (≦0.03 mm) relative to the apex. 
    
    
     
       Illustrated embodiments of the invention are described in greater detail below with reference to the drawings. 
       Therein: 
         FIG. 1  is a perspective view of a bearing according to a first embodiment, 
         FIG. 2  is a perspective view of a bearing according to another embodiment, 
         FIG. 3  is a section through the bearing assembly from  FIG. 2  in its installed state, and 
         FIG. 4  shows a bearing shell half according to another embodiment. 
     
    
    
       FIG. 1  shows a bearing  1  with an upper shell  4  and a lower shell  3 . While the lower shell  3  is a one-piece smooth shell, the upper shell  4  has two parts and is composed of a bearing shell assembly  10  with a length B 1  having two semicylindrical bearing shell halves  11  with a width B 2  that are arranged at a spacing from each other such that an intermediate space  12  is formed between the two bearing shell halves  11  that forms an oil duct  14  together with the bearing housing in its installed state. This is explained in greater detail in conjunction with  FIG. 3 . 
       FIG. 2  shows another embodiment of a bearing  1 , with the upper shell  4  also being made in two pieces. The bearing shell assembly  10  is formed by two bearing shell halves  11 ′ arranged at a spacing from each other, each of which has an axial bearing part  13  on its outer edge. Bearings of this type are used as main crankshaft bearings  2 , among other things. The lower shell  3  is composed of a one-piece smooth shell in this example as well. 
     A lower shell that has two pieces and is formed by two bearing shells arranged at a spacing from each other may also be used in combination with a single upper shell in mass balance transmission bearings. 
       FIG. 3  shows a partial section of the bearing  1  shown in  FIG. 2 , with the section running through the bearing shell assembly  10 . In addition, A bearing housing  20  is shown having at its center an oil-supply passage  21 . This oil supply  21  empties into the intermediate space  12  between the two bearing shell halves  11 ′ forming the oil duct  14 . The entire bearing shell thickness LD is available for the oil duct  14 . 
       FIG. 3  shows a main crankshaft bearing  2  whose bearing housing  20  is formed by a connecting rod. In this example, the bearing support  22  is the large connecting rod eye. 
       FIG. 3  is shows a mass balance transmission bearing, with the lower shell in this case being formed by two bearing shell halves arranged next to one another axially. 
       FIG. 4  shows a perspective view of a bearing shell half with an axial bearing part  13 . Each end  16  of the semicylindrical bearing shell half  11 ′ has a retaining formation  15  that projects radially outward. 
     The following table shows the length B 2  and the ratio V=D/B 2  for the bearing shell halves, with D designating the outer diameter of the bearing shells. In addition, the associated widths B 1  of the bearing shell assembly are listed. B 1  therefore also includes the width B 4  of the oil duct. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 
               
               
                   
               
               
                 D [mm] 
                 B 1  [mm] 
                 B 2  [mm] 
                 V = D/B 2  [mm] 
                 B 4  [mm] 
               
               
                   
               
             
            
               
                 20 to 22 
                 10-20 
                 4-8  
                 5.5-2.5  
                 2-12 
               
               
                 &gt;22 to 24 
                 10-20 
                 4-8  
                  6-2.75 
                 2-12 
               
               
                 &gt;24 to 28 
                 20-22 
                 4-10 
                  7-2.4 
                 2-14 
               
               
                 &gt;28 to 34 
                 12-22 
                 4-10 
                 8.5-2.8  
                 2-14 
               
               
                 &gt;34 to 40 
                 12-25 
                 5-10 
                  8-2.4 
                 2-17 
               
               
                 &gt;40 to 45 
                 12-25 
                 5-10 
                 9-4  
                 2-15 
               
               
                 &gt;45 to 60 
                 12-25 
                 5-10 
                 12-4.5 
                 2-15 
               
               
                 &gt;60 to 80 
                 12-28 
                 5-12 
                 16-5   
                 2-18 
               
               
                 &gt;80 to 100 
                 12-35 
                 5-12 
                 20-6.7 
                 2-25 
               
               
                 &gt;100 to 120 
                 14-40 
                 6-15 
                 20-6.7 
                 2-28 
               
               
                 &gt;120 to 150 
                 25-60 
                 10-25  
                 15-4.8 
                 5-40 
               
               
                   
               
            
           
         
       
     
     REFERENCE CHARACTERS 
     
         
           1  Bearing 
           2  Main crankshaft bearing 
           3  First bearing shell 
           4  Second bearing shell 
           10  Bearing shell assembly 
           11 ,  11 ′ Semicylindrical bearing shell half 
           12  Intermediate space 
           13  Axial bearing part 
           14  Oil duct 
           15  Retaining formation 
           16  Partial surface 
           20  Bearing housing 
           21  Oil supply 
           22  Bearing support