An engine valve includes a stem, a head comprising an outer lip surface, a seating surface extending from the outer lip surface toward the stem, and a combustion surface extending from the outer lip surface on the opposite side of the head as compared to the seating surface. The combustion surface includes a first convex arcuate surface spaced away from the outer lip surface, at least partially forming a raised ring, and a first concave arcuate surface spaced away from the outer lip surface, at least partially forming a dimple.

An assembly-free tool for maintenance of an engine in a vehicle is described. The tool comprises a bar extending in an axial direction and having a first portion with a first end and a second portion with a second end and a housing surrounding the first portion of the bar. The bar is axially translatable in relation to the housing. The housing comprises an embedded locking structure for holding the bar in a locking position to stop the movement of the bar in the axial direction. The bar, the housing and the locking structure are retained as one unit such that they are non-detachable from each other.

A cover body (2) for a valve rotating device includes a ring-shaped upper part (4) and a ring-shaped lower part (6). The upper part (4) and the lower part (6) are axially spaced apart and are adapted to accommodate an axial spring element (24) therebetween. The upper part (4) and the lower part (6) are connected to one another by at least one connecting piece arranged at the location opposite an insertion position of the axial spring element (24). A valve rotating device (12) having such a cover body is also provided. A ring-shaped base body (22) has a plurality of pockets (16) oriented in a circumferential direction, in each of which a ball (14) and a tangential spring (32) are arranged. The pockets (16) have a variable depth in the circumferential direction such that inclined raceways (26) for the balls (14) arranged therein are formed. The tangential springs (32) push the balls (14) toward an end of the respective pocket (16). The axial spring element (24) is ring-shaped and a first end of the axial spring element (24) is supported on an ring-shaped stop surface (18) of the base body (22) and a second end of the axial spring element (24) is supported on a surface of the upper part (4) of the cover. A surface of the lower part (6) facing away from the axial spring element (24) rests against the balls (14), and wherein the halls (14) and the axial spring element (24) are arranged overlapping in the axial direction. A method for producing a cover both (2) for a valve rotating device is also provided.

A mover is attracted and is moved in an axial direction with a predetermined stroke by a magnetic force generated between a stator and the mover when a coil is energized. The stator includes: a first stator positioned at a side where a stroke start position of the mover is located, and a second stator positioned at another side where a stroke end position of the mover is located. The mover includes a tapered portion which has a diameter progressively reduced toward the second stator, and a small-diameter cylindrical portion which is shaped in a straight form and has a constant outer diameter along an entire axial extent of the small-diameter cylindrical portion. An outer wall of the small diameter cylindrical portion has the outer diameter that is equal to an outer diameter of a smallest-diameter part of the tapered portion.

A cam having at least two part cams are arranged axially behind one another along a longitudinal axis includes an undercut between the cam parts. The part cams have running faces which lie radially on the outside of the part cams and have different variable running face contours. The undercut has a profile with a variable contour which is dependent in each case on that adjacent running face contour which is at a smaller radial spacing from the longitudinal axis than the other running face contour.

A production method for a valve body of a hollow valve includes providing a preform with a valve head and a tubular wall which surrounds a cylindrical cavity. The tubular wall is flow formed above a flow forming mandrel which is inserted into the cavity in order to increase a length of the tubular wall. A hollow valve produced by flow forming is also disclosed.

A method for producing a valve body of a hollow valve includes providing a workpiece blank or semi-finished product, spin extruding the workpiece to produce a preform having a cup with a hollow shape formed by the cup wall. A hollow valve produced by this method is also provided.

A hollow engine valve includes a shaft portion and an umbrella portion of which diameter is enlarged to form an umbrella shape to be provided on a base end of the shaft portion, a cooling material being enclosed in a hollow portion that is at least formed inside the shaft portion. The shaft portion comprises a first shaft portion in a tip end side, a second shaft portion that is provided in a base end side to have an outer diameter larger than that of the first shaft portion, and a stepped portion formed by a difference in the outer diameters between the first and second shaft portions. A wall thickness of the stepped portion is larger than that of the second shaft portion.

A fluid control valve unit includes: a fluid control valve including a sleeve that defines an axis and a spool slidably disposed in the sleeve; a passage member including an inner peripheral surface to which the sleeve is fitted, passages, an annular receiving part facing one end of the sleeve, an opening adjacent to the annular receiving part, and an annular groove formed adjacent to the other end of the sleeve and recessed from the inner peripheral surface; a filter member including an elastic part sandwiched between the one end of the sleeve and the annular receiving part and exerting a biasing force in the axial direction; and a snap ring fitted in the annular groove for receiving the other end of the sleeve and detachably receiving the spool.

A harmonic drive, more particularly in an electromechanical camshaft phaser, comprises a drive element (2), a flexible transmission element (26) connected to the drive element (2) and having external teeth (29), and an output element (4) that is designed as a ring gear and has internal teeth (30) that partially mesh with the external teeth (29). The flexible transmission element (26) is pot-shaped, and is coupled in a torque-transmitting manner to the drive element (2) radially inside the outer teeth (29).