Influencing Densification of PM Gears

Klocke, Fritz; Gorgels, Christof; Kauffmann, Philipp; Gräser, Eva

doi:10.1007/978-3-642-24491-9_35

Cited by 2 publications

(1 citation statement)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Sintered PM gears have lower density than wrought steel, the pores remaining after pressing and after the removal of the lubricant during the sintering step of the PM processing is the root for the lower density in traditional sintering technology. The lower density causes problems when it comes to the fatigue loading and durability of the PM gears [6,7]. Therefore, reaching the full density for a PM gear is a vital pre-request to meet, before using them for high performance applications [8].…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Analysis of the Gear Size Influence on Density Variations and Distortions during the Manufacturing of PM Gears with an Innovative Powder Processing Route Incorporating HIP

Khodaee

Melander

2018

JMMP

View full text Add to dashboard Cite

The paper is the result of research intended to develop a process route for the manufacturing of powder metallurgical (PM) gears for application in transmissions units for heavy duty powertrain applications. The main problem of PM for such applications is that the generated pores that occur through conventional pressing and sintering processes reduce the gear strength, which reduces the capacity for power transmission by the gear. In prior work, removing the pores and reaching 100% density by adding Hot Iso-static Pressing (HIP) after two times pressing and two times sintering steps in the process route was suggested to solve the mentioned problem. During the investigations of this work it was revealed that the gear dimensions could influence the process results with respect to geometrical distortions. In this paper we have presented a finite element (FE) model based analysis on how the gear geometrical parameters influenced the distortions occurring in HIP. The simulation model is validated with experiments. Furthermore, the simulation model is used to create a prediction model for further investigations. The research showed that PM gears with different sizes during the proposed process route behaved differently in terms of distortions. This was illustrated with a series of simulations with different gear geometries. A regression model was developed based on the FE results for further practical predictive use. The distortions caused by HIP should be considered in the process design to prevent expensive post processes afterwards to reach the gear with accurate geometry and keep the costs of manufacturing low. It is concluded that it is possible to use the innovative process route including HIP to reach the full density and close all the open pores but not for all kind of gear geometries.

show abstract

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Analysis of the Gear Size Influence on Density Variations and Distortions during the Manufacturing of PM Gears with an Innovative Powder Processing Route Incorporating HIP

Khodaee

Melander

2018

JMMP

View full text Add to dashboard Cite

show abstract

Optimized density profiles for powder metallurgical gears

Gräser

Hajeck

Bezold

et al. 2014

Prod. Eng. Res. Devel.

View full text Add to dashboard Cite

In gear production, resource efficiency considering material, energy and time can be achieved using a powder metallurgical process chain. Furthermore, powder metallurgical gears have a lower weight, which will improve the fuel efficiency of a gear box as well. Currently powder metallurgical gears are not used in series-production automobile gear boxes. The main reason for this is a lower expected tooth root fatigue strength, which can be increased using surface densification by rolling. The investigation of how the powder metallurgical (PM) gear manufacturing has to improve in order to gain the possible resource efficiency, is funded in the Priority Program "Resource efficient machine elements”. This paper considers a two-step approach to increase the tooth root fatigue strength of PM gears. The first step is to calculate the fatigue strength considering the density profile of the gear. This first step will result in a description of the optimal density profile. The second step is an investigation of how the density profile and the manufacturing properties can be influenced using different process designs. This step will result in a guideline to change the density profile to the one described in the first step. The combined knowledge of which density profile is necessary and how it can be achieved will give the chance to increase the tooth root fatigue strength of powder metallurgical gears. This paper considers the first part of both steps of the approach

show abstract

Influencing Densification of PM Gears

Cited by 2 publications

References 5 publications

Numerical and Experimental Analysis of the Gear Size Influence on Density Variations and Distortions during the Manufacturing of PM Gears with an Innovative Powder Processing Route Incorporating HIP

Numerical and Experimental Analysis of the Gear Size Influence on Density Variations and Distortions during the Manufacturing of PM Gears with an Innovative Powder Processing Route Incorporating HIP

Optimized density profiles for powder metallurgical gears

Contact Info

Product

Resources

About