SLIDING CAM ARRANGEMENT FOR VARIABLE ACTUATING GAS EXCHANGE VALVES OF AN INTERNAL COMBUSTION ENGINE
A sliding cam arrangement for the variable actuation of gas exchange valves of an internal combustion engine, having a camshaft which has toothing regions with an external toothing, wherein the toothing regions mesh in each case with an internal toothing of a cam carrier, wherein the ratio of base circle radius R2 of the cam carrier to tip circle radius R1 of the toothing of the camshaft satisfies the following criteria: R2/R1<1.55.
Latest Dr. Ing. h.c. F. Porsche Aktiengesellschaft Patents:
- METHOD FOR DYNAMICALLY ADJUSTING A VOLUME LEVEL IN AN ONLINE MEETING
- HYDRAULIC SYSTEM FOR A HYDRAULICALLY ADJUSTABLE VEHICLE SHOCK ABSORBER
- COMPRESSION PAD WITH A SELECTIVELY PERMEABLE OR SEMIPERMEABLE SEPARATING LAYER AND A METHOD FOR PRODUCING A BATTERY CELL STACK WITH THE COMPRESSION PAD
- COMPRESSION PAD WITH SHAPE MEMORY FUNCTION AND ASSOCIATED MANUFACTURING METHOD
- APPARATUS FOR COOLING A BATTERY
This application claims priority to German Patent Application No. 10 2012 109 690.2, filed Oct. 11, 2012, which is incorporated by reference herein in its entirety.
FIELD OF THE INVENTIONThe invention relates to a sliding cam arrangement for the variable actuation of gas exchange valves of an internal combustion engine, having a camshaft which has toothing regions with an external toothing, wherein the toothing regions mesh in each case with an internal toothing of a cam carrier.
BACKGROUND OF THE INVENTIONSliding cam arrangements of said type are well known from the prior art. For example, DE 10 2008 035 935 A1, which is incorporated by reference herein, discloses a sliding cam arrangement which has a camshaft with toothing regions, on which camshaft there are provided in each case cam carriers with two cams which engage with a respective gas exchange valve. To effect a displacement of the respective cam carrier, actuators are provided which, by means of drivers and grooves provided on the cam carriers, permit a displacement of the cam carriers in an axial direction. In the automotive field, the optimization of installation space and weight is of ever greater importance in particular against the background of increasing engine efficiency. Against this background, efforts made for the optimization of camshaft arrangements have been directed in particular to material optimization and improvements. It has nevertheless been found that the existing sliding cam arrangements have a considerable need for improvement in particular with regard to the adverse effects of the mass moment of inertia of the cam carriers.
SUMMARY OF THE INVENTIONDescribed herein is a sliding cam arrangement which exhibits improved dynamic behavior in an inexpensive manner which is expedient with regard to assembly.
The ratio of a base circle radius R2 of the cam carrier to a tip circle radius R1 of the toothing of the camshaft satisfies the following criteria: R2/R1<1.55. The mass inertia behavior of the sliding cam arrangement can be improved significantly in this way. Furthermore, the actuators require less power to displace the respective cam carrier, which yields an installation space reduction and cost savings with regard to the actuators too. Also, a camshaft which must possibly be produced with a relatively large diameter, because predefined spacings to the gas exchange valves must be maintained in the cylinder head, does not have an adverse effect on the overall performance of the sliding cam arrangement according to the invention. It has proven to be particularly advantageous for the ratio R2 to R1 to lie in the range from 1.2 to 1.55.
The invention will be explained in more detail below on the basis of a drawing, in which:
Claims
1. A sliding cam arrangement for variable actuation of gas exchange valves of an internal combustion engine, comprising a camshaft having toothing regions with an external toothing, wherein the toothing regions mesh with an internal toothing of a cam carrier, wherein a ratio of a base circle radius R2 of the cam carrier to a tip circle radius R1 of the toothing of the camshaft is less than 1.55.
2. The sliding cam arrangement as claimed in claim 1, wherein the ratio is between 1.2 and 1.55.
Type: Application
Filed: Oct 7, 2013
Publication Date: Apr 17, 2014
Applicant: Dr. Ing. h.c. F. Porsche Aktiengesellschaft (Stuttgart)
Inventors: Steffen Matthias Kappler (Neidlingen), Frank Ickinger (Pleidelsheim)
Application Number: 14/047,382
International Classification: F01L 1/344 (20060101);