Gear and Power Transmission Research Laboratory: Research
Current Consortium Projects
The following is a representative list of the current projects that are funded by the members of the GearLab Consortium. Each member has full access to the findings of these research projects including papers and theses.
- Development of a spline load distribution model, validation, and prediction of root stresses
- Development of a planetary load distribution model
- Planetary gear train efficiency
- Development of advanced EHL models for gear contacts
- Effect of spacing errors on dynamic stress factors and loaded transmission error
- Development of a load distribution model for spiral bevel and hypoid gears
- A model to predict overall transmission error of a planetary gear set
- Enhancement of current WindowsLDP and RMC
Current Individually Sponsored Projects:
These projects are funded by a single company or a group of companies through an individual contract. The findings of these research projects are kept limited to the sponsoring company and are not shared with the Consortium members unless they are disclosed by the sponsoring company. The following is the list of the recent and current individually funded research projects.
- Pratt & Whitney Center of Excellence in Gearbox Technology, Pratt & Whitney
- An Investigation of Drag Losses of Helical Gears, General Motors
- An Experimental Investigation of the Impact of Forced Lubrication Parameters on Gearbox Efficiency and Pitting Life, Eaton Corporation
- Measurement of Load Transmission Error of a Hypoid Pair with Misalignments, AAM
- Development of Planetary Gear Dynamics Analysis Modules in pRMC and PTA (Co-PI: Dr. D. Talbot), Hyundai Motor Company
- An Investigation of the Effect of Grind-Polishing Process on Gear Efficiency, General Motors
- Evaluation of Loaded Transmission Error and Root Stresses of Hypoid Gear Pairs Subject to Misalignments, General Motors
- Evaluation of Contact Fatigue Characteristics of Grind-Polished 4118M Spur Gears, Allison Transmission
WindowsLDP (Load Distribution Program) is a quasi-static gear design and analysis tool for external and internal spur and helical gear pairs. This software program has been adapted and used extensively by most of the consortium members as the main gear design and analysis tool. WindowsLDP employs computationally efficient and accurate semi-analytical formulations to compute the load distribution between multiple mating teeth of gears. With the predicted load distribution, it computes the loaded transmission error, root and contact stress distributions, mesh stiffness functions, tooth forces as well as other design evaluation parameters such as lubricant film thickness and surface temperature. WindowsLDP’s capabilities also include multi-torque analyses and manufacturing robustness analyses. Tooth modifications of various forms can be entered interactively or can be read from the tooth surface measurements. The results are presented by an interactive graphical user interface that provides the user the flexibility to process and present them in desired formats.
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RMC (Run Many Cases) is designed to take advantage of LDP's capability to provide a macro-level design capability for external spur and helical gear pairs. RMC considers user-defined ranges of basic gear design parameters including number of teeth, pressure angle, helix angle, tool addendum and dedendum, and face width etc. to generate a large number of candidate gear designs meeting the design requirements such as center distance and gear ratio. These candidate gear designs are analyzed by WindowsLDP and evaluated based on design requirements imposed by the user interactively to arrive at an optimal design solution.
SplineLDP is a quasi-static load distribution program for splines. It is capable of analyzing side fit splines with and without back-side contact or major/minor fit. It computes the contact stress and load distribution for pure torsion, gear loaded, or arbitrarily loaded splines at various torque values. Influence of micro-geometry (profile and lead modification) and index errors can be included in the analysis. Single or multi-torque analysis can be analyzed at a single or multiple rotational positions.
HAP (Hypoid Analysis Program) is a quasi-static gear load distribution analysis tool for spiral bevel and hypoid gear pairs. It simulates the face-milling and face-hobbing processes to define the gear tooth surfaces from the machine settings and cutter parameters specified by a given special analysis file. HAP incorporates all types of misalignments. It uses the corresponding ease-off topography to determine the unloaded tooth contact lines and the unloaded transmission error. A semi-analytical model that uses the shell theory is used to define the compliance matrix that is used for loaded tooth contact analysis. With the predicted load distribution, HAP computes the loaded transmission error, contact stresses and the contact pattern of the gear pair. The results are presented by an interactive graphical user interface that provides user the flexibility to process and present them in desired formats.
Gleason Gear and Power Transmission Laboratories
The Gleason Gear and Power Transmission Laboratory consists of 6 high-bay rooms having 6000 square feet (about 550 square meters) of laboratory space with built in facilities such as isolated test beds and one computational research laboratory that houses the research team. The test facilities are arranged in four laboratories, dedicated to experimental investigation of different aspects of gearing.
Gear Dynamics Laboratory: houses a number of state-of-the-art test set-ups and machines to investigate the behavior of gear pairs and gear systems under dynamic operating conditions. It includes the Gear Dynamics Test Machine that is designed to measure transmission error, vibrations and root strains of spur and helical gears with or without shaft misalignments. Both encoder- and accelerometer-based transmission error measurement systems are incorporated with this test machine. Another test set-up housed in this laboratory is a planetary gear test machine to measure planet load sharing, efficiency and dynamic behavior of planetary gear sets under loaded conditions. Other test set-ups in the lab include a low-speed loaded dynamometer that is currently being used for planetary gear set and hypoid transmission error measurements as well as full-scale transmission dynamometer that is suitable for loaded dynamic tests of gearboxes, transmissions as well as spin tests of axles.
Gear Efficiency Laboratory: houses a number of test machines designed specifically to evaluate efficiency and durability aspects of gears, gear materials and lubricants. Two twin-disk test machines for contact fatigue, scoring and traction measurements and an efficiency test machine shown here with helical gear efficiency fixtures. This efficiency test machine is designed to evaluate loaded and unloaded power losses of gear pairs under high-speed (up to 10,000 rpm) and high-load conditions (up to 700 Nm).
Gear Fatigue Laboratory: houses test machines to evaluate fatigue lives of gears under both automotive and aerospace conditions. Three standard FZG gear durability test machines for performing pitting, tooth bending fatigue and scoring tests are housed in this laboratory. Also included in this laboratory is a MTS load frame fixture to perform single-tooth bending fatigue tests.
Gear Metrology Laboratory: supports the experiments in other laboratories by providing systems for measurement of surface roughness and tooth profiles, and imaging the test surfaces. A Gleason-Goulder single-flank unloaded transmission error tester, a Gleason M&M Gear CMM, a Taylor Hobson Tally-Surf surface roughness profiler and miscellaneous digital microscopes and data collection and analysis instrumentation are also included in this lab.
Gear Computation Room: for graduate student's office.