Patent DE-102008031752-A1 (DE)
Title: Single-piece valve tappet for valve drive of a combustion engine, comprises a start-up section with a start-up area for a valve control element, and two guidance sections formed in the form of hollow cylindrical sections
Inventor: GEYER NORBERT
IPC: B23P13/00
Filed: 2008-07-04
Abstract: The single-piece valve tappet comprises a start-up section (7) with a start-up area (8) for a valve control element, two guidance sections (2, 4) formed in the form of hollow cylindrical sections in confrontation with a joint cylinder axis, where the guidance sections are equipped respectively with a guidance area (4, 5) for guiding the valve tappet along a direction of movement, and a connection section formed in the area of the cylinder axis at the start-up sections. Each guidance section is connected by two first stiffening sections with the connecting sections. The single-piece valve tappet comprises a start-up section (7) with a start-up area (8) for a valve control element, two guidance sections (2, 4) formed in the form of hollow cylindrical sections in confrontation with a joint cylinder axis, where the guidance sections are equipped respectively with a guidance area (4, 5) for guiding the valve tappet along a direction of movement, and a connection section formed in the area of the cylinder axis at the start-up sections. Each guidance section is connected by two first stiffening sections with the connecting sections. The both first stiffening sections are arranged so that it conically taper in the direction to the connection sections. Each guidance section is limited by two straight longitudinal edges extending itself in movement direction and two curved transverse edges extending itself vertical to the movement direction. The first stiffening sections are connected respectively with the longitudinal edges of the guidance section. A second stiffening section connecting the guidance wall with the connecting section is arranged between the first stiffening sections. The two second stiffening sections are arranged in a parallely running direction and connected with the start-up section, which has a thickness dimensioned along the start-up area different in the movement direction. The thickness of the start-up section in a middle area of the start-up section is smaller than in the adjacent edge area of the start-up section. The first and the second stiffening sections form a recess jointly on the side turned to the start-up section and are formed in the form of ribs self-extending in movement direction. The short side edges of the start-up section are formed in the supervision with a joint midpoint. The short side edges of the start-up section are measured in the circumference direction than the breadth edge of the guidance section. The connection section is a sleeve concentrically arranged to the cylinder axis for the reception of the hydraulic valve play adjuster element. The second stiffening section is equipped with a hydraulic channel flowing into a cavity of the sleeve. The connection section is a cylindrical projection concentrically arranged to the cylinder axis. The valve tappet is produced by injection molding of metal powder or precision casting. An independent claim is included for a method for the production of single-piece valve tappet.