Fuel unit pump and internal combustion engine comprising it

A roller tappet for a fuel pump in an internal combustion engine has a body 10 with a cam roller carrier 13 coupled to it. The carrier is elastically deformable so that the roller tappet may be aligned to a camshaft lobe. A cam roller 12 is mounted in the carrier and rotates around an axis RA. The cam roller carrier may be at least partially made of a material with a lower elastic modulus (be more elastic than) that of the roller tappet body and can potentially be made of spring steel. The cross-section of the cam roller carrier may be arcuate or form an arch. The carrier may be welded or brazed to the body of the tappet or lifter. The roller portion 12 may be mounted in the carrier via pins (11, figure 4) located on portions 13a, 13b which may be arranged on flanges or arms 14a, 14b of the carrier. The cam roller 12 may have a flat lateral surface. The cam roller carrier may tilt in a rotation plane comprising the rotation axis RA and be parallel to the body axis of the tappet body BA.