Camshaft, cam angle detection device, and internal combustion engine

Abstract

A camshaft includes a sensor rotor and a plurality of cams. The sensor rotor includes a base circle, and a projection portion formed on an outer peripheral surface of the base circle. A long diameter part of that one of the plurality of cams which is closest to the sensor rotor is placed within a region sandwiched between a first virtual line extending from the shaft center of the camshaft and a second virtual line extending from the shaft center of the camshaft in an axial view of the camshaft, the first virtual line passes through one circumferential end of the projection portion of the sensor rotor in an axial view of the camshaft, and the second virtual line passes through the other circumferential end of the projection portion of the sensor rotor in an axial view, of the camshaft.

1 . A camshaft comprising:
 a sensor rotor including a base circle, and a projection portion formed on an outer peripheral surface of the base circle so as to be detected by a cam angle sensor; and   a plurality of cams each having a nose including a long diameter part configured such that its radial length from a shaft center of the camshaft is longer than a radius of the base circle of the sensor rotor, wherein   the long diameter part of that one of the plurality of cams which is closest to the sensor rotor is placed within a region sandwiched between a first virtual line extending from the shaft center of the camshaft and a second virtual line extending from the shaft center of the camshaft in an axial view of the camshaft, the first virtual line passes through one circumferential end of the projection portion of the sensor rotor in the axial view of the camshaft, and the second virtual line passes through the other circumferential end of the projection portion of the sensor rotor in the axial view of the camshaft.   
     
     
         2 . An internal combustion engine comprising:
 the camshaft according to  claim 1 ;   a plurality of journal bearings that rotatably support the camshaft; and   a thrust bearing placed between the sensor rotor and that one of the journal bearings which is closest to the sensor rotor.   
     
     
         3 . A cam angle detection device comprising:
 a sensor rotor provided on a camshaft including a cam, the sensor rotor including a projection portion on outer peripheral surface of the sensor rotor; and   a cam angle sensor configured to output a detection signal of a first prescribed value when the projection portion of the sensor rotor approaches the cam angle sensor and to output the detection signal of a second prescribed value different from the first prescribed value when the projection portion is distanced from the cam angle sensor, wherein:   the projection portion is configured such that a first rotational phase range includes a whole second rotational phase range;   the first rotational phase range is a rotational phase range of the camshaft in which the projection portion approaches the cam angle sensor and the cam angle sensor outputs the detection signal of the first prescribed value; and   the second rotational phase range is the rotational phase range of the camshaft in which a nose of the cam approaches the cam angle sensor so that the cam angle sensor outputs the detection signal of the first prescribed value.