Internally cooled valve for internal combustion engines, as well as method and device for the production thereof

Abstract

A method and a device for the production of an internally cooled inlet or outlet valve for internal combustion engines, together with the resultant valve includes provision of a workpiece, which has a cylindrical stem and a cylindrical hole and, extends in the axial direction from one end of the valve stem. The method includes reshaping the end of the valve stern by form rolling of the cylindrical stem to a smaller diameter, wherein a diameter of the cylindrical hole is reduced, wherein the cylindrical hole remains. The method further includes reshaping by form rolling the section of the workpiece that is adjacent to the valve stem to form the valve head.

1 . A method for the production of an internally cooled valve ( 4 ) for internal combustion engines, comprising: 
       provision of a workpiece ( 14 ,  16 ), which comprises a stem and a cylindrical hole ( 26 ,  28 ), which extends from one end of the valve stem ( 36 ) in the axial direction,
 reshaping of the valve stem end ( 36 ) by form rolling of the stem to a smaller diameter, wherein a diameter of the cylindrical hole is reduced, wherein the hole ( 26 ,  28 ) remains, and 
 reshaping by form rolling of a section of the workpiece ( 14 ,  16 ) that is adjacent to the valve stem ( 8 ) to form the valve head. 
 
     
     
         2 . The method for the production of an internally cooled valve ( 4 ) for internal combustion engines, in accordance with  claim 1 , wherein prior to the form rolling process the workpiece ( 14 ,  16 ) comprises a diameter of at least that of the valve disk ( 6 ) of the finished valve, and further comprising:
 form rolling of a transition section between the valve head and the valve stem ( 8 ) to form a concave fillet.   
     
     
         3 . The method for the production of an internally cooled valve ( 4 ) for internal combustion engines, in accordance with  claim 1  or  2 , wherein the workpiece ( 16 ) is cup-shaped, wherein
 the cup-shaped workpiece ( 14 ,  16 ) has a diameter at a base of the workpiece ( 16 ) that corresponds at least to that of the valve disk ( 6 ), 
 wherein the cylindrical hole is a blind hole ( 26 ), which extends from one end of the valve stem ( 36 ) in the direction of the base of the cup-shaped workpiece ( 16 ), and 
 wherein the form rolling process comprises a reshaping of the stem and a shaping of the valve body. 
 
     
     
         4 . The method for the production of an internally cooled valve ( 4 ) for internal combustion engines, in accordance with  claim 3 , wherein
 an outer surface of the base of the workpiece ( 16 ) already has the shape of the valve disk ( 6 ).   
     
     
         5 . The method for the production of an internally cooled valve ( 4 ) for internal combustion engines, in accordance with  claim 3  or  4 , wherein the workpiece ( 16 ) is cup-shaped, and wherein
 the cup-shaped workpiece ( 16 ) has a larger diameter at a base of the workpiece ( 16 ) than in the area of the cylindrical stem. 
 
     
     
         6 . The method for the production of an internally cooled valve ( 4 ) for internal combustion engines, in accordance with one of the preceding claims, wherein
 the workpiece ( 14 ,  16 ) is held between the rollers by means of guides.   
     
     
         7 . The method for the production of an internally cooled valve ( 4 ) for internal combustion engines, in accordance with one of the preceding claims, wherein
 the workpiece ( 14 ,  16 ) is hot rolled.   
     
     
         8 . The method for the production of an internally cooled valve ( 4 ) for internal combustion engines, in accordance with one of the preceding claims, further comprising:
 axial movement of the workpiece ( 14 ,  16 ) in the direction of the stem end ( 36 ) during the rolling process.   
     
     
         9 . The method for the production of an internally cooled valve ( 4 ) for internal combustion engines, in accordance with one of the preceding claims, further comprising:
 rotation of the workpiece ( 14 ,  16 ) during the rolling process.   
     
     
         10 . The method for the production of an internally cooled valve ( 4 ) for internal combustion engines, in accordance with one of the preceding claims, further comprising:
 turning of the valve stem ( 8 ) to a desired outer diameter, after a desired inner diameter of the valve stem ( 8 ) has been achieved by rolling.   
     
     
         11 . The method for the production of an internally cooled valve ( 4 ) for internal combustion engines, in accordance with one of the preceding claims, wherein
 the provision of the workpiece ( 14 ,  16 ) comprises a provision of the workpiece ( 14 ,  16 ) with a non-cylindrical stem with an outer contour ( 70 ) and the cylindrical hole ( 26 ,  28 ),   wherein the reshaping of the valve stem end ( 36 ) by form rolling comprises a   reshaping of the valve stem end ( 36 ) by form rolling of the stem to a smaller diameter, wherein a diameter of the cylindrical hole is reduced, and a non-cylindrical hole with an inner contour ( 72 ) remains.   
     
     
         12 . A device for the production of an internally cooled valve ( 4 ) for internal combustion engines, from a workpiece ( 14 ,  16 ), comprising:
 a rolling mill for purposes of round cross rolling or skewed rolling, wherein at least two forming rollers ( 42 ,  44 ) have a profile of an outlet valve.   
     
     
         13 . The device for the production of an internally cooled valve ( 4 ) in accordance with  claim 12 , further comprising:
 a mandrel, which can be inserted into a hole ( 26 ,  28 ) of a workpiece ( 14 ,  16 ) so as to guide the workpiece ( 14 ,  16 ) during the rolling process.   
     
     
         14 . The device for the production of an internally cooled valve ( 4 ) in accordance with  claim 12 , further comprising:
 at least one guide so as to hold and guide the workpiece ( 14 ,  16 ) between the rollers, wherein the at least one guide comprises a sliding member, or one or a plurality of rollers, which abut against an outer surface of the workpiece ( 14 ,  16 ).   
     
     
         15 . The device for the production of an internally cooled valve ( 4 ) in accordance with  claim 11 ,  12 ,  13 , or  14 , further comprising:
 at least one load cell on the at lease one guide, together with individually driven forming rollers ( 42 ,  44 ),   and a controller that controls the rotational speed of the forming rollers ( 42 ,  44 ) such that the force on the guides is minimised.   
     
     
         16 . The device for the production of an internally cooled valve ( 4 ) in accordance with one of the  claims 12  to  15 , characterised in that the axes of the rollers are arranged skewed relative to one another at an angle of 1° to 12°, preferably of 2° to 10°, and more preferably of 3° to 8°. 
     
     
         17 . The device for the production of an internally cooled valve ( 4 ) in accordance with  claim 16 , characterised in that the axis of the workpiece ( 14 ,  16 ) and the axes of the forming rollers ( 42 ,  44 ) are in each case arranged skewed relative to one another at an angle of 0.5° to 6°, preferably of 1° to 5°, and more preferably of 1.5° to 4°. 
     
     
         18 . The device for the production of an internally cooled valve ( 4 ) in accordance with one of the  claims 16  or  17 , wherein
 at least one of the forming rollers ( 44 ) has a hyperboloidal outer surface. 
 
     
     
         19 . The device for the production of an internally cooled valve ( 4 ) in accordance with one of the  claims 12  to  18 , wherein
 at least one of the forming rollers ( 42 ,  44 ) has a surface structure, which causes a transport of the material of the workpiece in the axial direction. 
 
     
     
         20 . The device for the production of an internally cooled valve ( 4 ) in accordance with one of the  claims 12  to  19 , further comprising: an axial guide or a clamping chuck, so as to guide and/or hold the workpiece ( 14 ,  16 ) from the disk face. 
     
     
         21 . The device for the production of an internally cooled valve ( 4 ) in accordance with one of the  claims 12  to  20 , further comprising: an actuator, so as to move the workpiece ( 14 ,  16 ) axially, from the base in the direction of the valve stem end ( 36 ). 
     
     
         22 . The device for the production of an internally cooled valve ( 4 ) in accordance with one of the  claims 12  to  21 , further comprising: a drive, so as to rotate the workpiece ( 14 ,  16 ) during the rolling process at a predetermined rotational speed. 
     
     
         23 . The device for the production of an internally cooled valve ( 4 ) in accordance with one of the  claims 12  to  22 , further comprising: a heating element, so as to heat the workpiece ( 14 ,  16 ) during the rolling process. 
     
     
         24 . An internally cooled valve ( 4 ) for internal combustion engines, characterised in
 that it has been reshaped from a workpiece ( 14 ,  16 ) using one of the methods of  claims 1  to  10 , or using a device according to any one of  claims 12  to  23 ,   wherein the workpiece ( 14 ,  16 ) comprises a stem, wherein the workpiece ( 14 ,  16 ) also comprises a cylindrical hole, which extends from one end of the valve stem ( 36 ) in the axial direction, wherein at least one stem has been reshaped by form rolling of the stem to a smaller diameter.   
     
     
         25 . An internally cooled valve ( 4 ) for internal combustion engines in accordance with  claim 24 , characterised in that prior to the form rolling process the workpiece ( 14 ,  16 ) comprises a diameter of at least that of the valve disk ( 6 ), and in that a valve head is produced with a concave fillet by means of form rolling. 
     
     
         26 . An internally cooled valve ( 4 ) for internal combustion engines in accordance with  claim 24  or  25 , characterised in
 that the workpiece ( 16 ) is cup-shaped, wherein 
 the cup-shaped workpiece ( 16 ) has a diameter at a base of the workpiece ( 16 ) that corresponds at least to that of the valve disk ( 6 ), wherein 
 the cylindrical hole is a blind hole ( 26 ), which extends from one end of the valve stem ( 36 ) in the direction of the base of the cup-shaped workpiece ( 16 ). 
 
     
     
         27 . An internally cooled valve ( 4 ) for internal combustion engines in accordance with  claim 26 , characterised in
 that the workpiece ( 16 ) is cup-shaped, wherein   the cup-shaped workpiece ( 16 ) has a larger diameter at a base of the workpiece ( 16 ) than in the area of the cylindrical stem.   
     
     
         28 . An internally cooled valve ( 4 ) for internal combustion engines in accordance with one of the  claims 24  to  27 , characterised in
 that after the reshaping process the cylindrical hole ( 26 ,  28 ) forms a cavity ( 10 ) that extends within the valve stem ( 8 ) and the valve disk ( 6 ), which cavity is partially filled with sodium ( 12 ) and sealed. 
 
     
     
         29 . An internally cooled valve ( 4 ) for internal combustion engines in accordance with one of the  claims 24  to  28 , characterised in
 that prior to the rolling process the workpiece ( 14 ,  16 ) has a non-cylindrical stem with an outer contour ( 70 ) and with a cylindrical hole ( 26 ,  28 ), 
 wherein as a result of the reshaping of the valve stem end ( 36 ) by form rolling the valve has a cylindrical valve stem and a non-cylindrical hole with an inner contour ( 72 ).