Cam follower for a valve train of an internal combustion engine

Patent metadata

Field	Value
Publication number	US-9556755-B2
Application number	US-201414770966-A
Country	US
Kind code	B2
Filing date	Jan 20, 2014
Priority date	Mar 8, 2013
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

A cam follower for a valve train of an internal combustion engine, the cam follower being formed as a lever, which is U-shaped in cross-section, and produced from steel sheet without machining, and which has a floor wall ( 3 ) and lateral walls ( 4 and 5 ) extending therefrom, wherein a valve stem support ( 10 ) is disposed as a groove ( 11 ) at one end of the lever in a surface of the floor wall ( 3 ) facing away from the lateral walls ( 4 and 5 ). Lateral guide walls ( 12 and 13 ) of the valve stem support ( 10 ) are formed by chipless shaping so as to extend from and counter to the lateral walls ( 4 and 5 ) and are connected to a support wall ( 14 ) that forms a valve stem support surface ( 10 a ). The valve stem support surface ( 10 a ) extends in a first plane ( 10 b ), which is spaced from a second plane ( 16 a ), which extends through an internal transition ( 15, 16 ) between the lateral walls ( 4 and 5 ) and the adjacent guide walls ( 12 and 13 ), in the direction of ends ( 19, 20 ) of the lateral walls ( 4 and 5 ). In order to reduce stress and resulting cracks, an inner radius R is provided at the transition ( 15 and 16 ), by which radius a free space ( 17, 18 ) is created between the lateral wall ( 4, 5 ) and the guide wall ( 12, 13 ), which free space narrows towards the end ( 19, 20 ) of the respective lateral wall ( 4, 5 ).

First claim

The invention claimed is:

1. A cam follower for a valve train of an internal combustion engine, comprising viewed in cross section, a U-shaped lever made from sheet steel in a non-cutting process including a base wall and side walls extending from said base wall, wherein a valve stem support formed as a groove is provided on one end of the lever in a surface of the base wall facing away from the side walls, the valve stem support includes side guide walls formed by a non-cutting shaping process extending from and counter to the side walls and are connected to a support wall forming a valve stem support surface, the valve stem support surface extends in a first plane that is spaced apart from a second plane extending through an inner transition between the side walls and the adjacent guide walls in a direction of free ends of the side walls, at the transition, an inner radius R is provided by which a free space is created between each of the side walls, and the guide walls and said free space narrows in the direction of the free end of the respective side wall, wherein the inner radius R and the free space are formed as a common indentation in the inner transition, in the side wall, and in the guide wall.

2. The cam follower according to claim 1 , wherein the respective free space narrows up to a contact of the respective guide wall on the respective side wall.

3. The cam follower according to claim 1 , wherein the free space has, in an area in which the inner radius R connects, a width B of ≧0.6 mm and the inner radius R≧0.3 mm.

4. The cam follower according to claim 1 , wherein the free space has a droplet-shaped contour.

5. The cam follower according to claim 1 , wherein the lever is constructed as a rocker arm or finger lever provided with a roller pocket for a cam roller.

6. A cam follower for a valve train of an internal combustion engine, comprising viewed in cross section, a U-shaped lever made from sheet steel in a non-cutting process including a base wall and side walls extending from said base wall, wherein a valve stem support formed as a groove is provided on one end of the lever in a surface of the base wall facing away from the side walls, the valve stem support includes side guide walls formed by a non-cutting shaping process extending from and counter to the side walls and are connected to a support wall forming a valve stem support surface, the valve stem support surface extends in a first plane that is spaced apart from a second plane extending through an inner transition between the side walls and the adjacent guide walls in a direction of free ends of the side walls, at the transition, an inner radius R is provided by which a free space is created between each of the side walls, and the guide walls and said free space narrows in the direction of the free end of the respective side wall, wherein the respective free space opens into a gap between the side wall and the guide wall, and the free space has, in an area in which the inner radius R connects, a maximum width that is at least 5 times a width of the gap.

7. A method for the non-cutting production of a cam follower comprising a lever formed from sheet steel, said lever is provided for a valve train of an internal combustion engine and being formed with an essentially a U-shaped cross section with a base wall and side walls extending essentially perpendicular to the base wall, and a valve stem support provided on one end of the lever is formed as a groove in the base wall, having side guiding walls formed by a non-cutting shaping process, starting from the side walls, extending opposite to said walls, and are connected to a support wall forming a valve stem support surface, the valve stem support surface extending in a first plane that is spaced apart to a second plane extending through an inner transition between the side walls and the adjacent guiding walls in the direction of free ends of the side walls the method comprising in a first processing step, punching a blank out from the sheet steel, in a second processing step, embossing two grooves with a blank radius R R in a longitudinal direction of the blank in a surface of the blank, shaping the blank in a third processing step for the production of said U-shape, and in a fourth processing step, embossing the groove in the base wall, creating a transition from each of the side walls to the base wall at the two grooves, wherein, due to the embossed blank radius R R , said transition is formed with an inner radius R and a free space that has a drop-shaped contour, viewed in a cross section of the lever.

Assignees

• Schaeffler Technologies Ag

Inventors

• Dupke Stefan
• Schewe Michael
• Sailer Peter

Classifications

• F01L1/46

  Component parts, details, or accessories, not provided for in preceding subgroups · CPC title

• B21D53/84

  other parts for engines, e.g. connecting-rods · CPC title

• B21K1/205

  rocker arms · CPC title

• B21D35/001

  Shaping combined with punching, e.g. stamping and perforating · CPC title

• F01L1/181 Primary

  Centre pivot rocking arms · CPC title