Industrial machinery and heavy equipment

Transcription

1 Industrial machinery and heavy equipment Product LMS LMS Engineering services help tractor manufacturer to successfully launch a continuously variable transmission vehicle Business challenges Resolve noise issues due to adoption of CVT, especially gear whine Overcome the challenges of introducing an entirely new product Meet the demands of an increasingly competitive market Keys to success Determine the correlation between alignment parameters and noise Take advantage of LMS Engineering s measurement, analysis and simulation capabilities Leverage LMS Engineering s experience in handling similar issues Results Successfully launched a CVT tractor Reduced transmission noise by more than 3dB in critical conditions and significantly improved cabin sound quality Saved at least one test cycle with new prototype parts, equating to at least three months Siemens PLM Software s LMS experts enable to significantly cut transmission noise and save at least one test cycle knows one size doesn t fit all produces tractors that are known for their quality and reliability. In fact, the Finnish-based firm is one of the only companies in the world to boast the production of customized tractors and agricultural equipment. s modular system of tractor assembly enables the company to produce machines that meet each customer s requirements, so it is obvious why its tagline is: Custom-built tractors. Choosing from s à la carte selection provides the customer with over half a million combinations. In a homogenized world, stands out from the crowd. The company s continued drive toward innovation remains imperative for its future success. With tractor sales worldwide set to fall in 2009, had to continue to meet customer s growing demands in the face of stiff competition from the likes of John Deere and Case New Holland, while at the same time making inroads into emerging markets. For these reasons, embraced the development of continuously variable transmission (CVT) for its vehicles. Vegetable and specialist growers originally adopted the concept of using CVT in tractors because they recognized the potential it had to offer. Increasingly, CVT has entered the mainstream and is being taken on by farmers and contractors who appreciate its flexibility. It is a step-less transmission that doesn t require a gear stick, freeing up more room for the driver in the cab. Furthermore, the CVT offers better fuel economy than conventional transmissions since the engine can run at its most efficient revolutions per minute (RPM) in a range of speeds. From an engineering perspective, however, CVTs present quite a challenge. Noise issues are

2 LMS Engineering services and the team work to identify a critical gear whine noise issue (see rainflow diagram) during the engine run up. Time is money. We learned a lot through this project and now have much better capabilities to work with these issues. more prevalent and also more difficult to solve due to the infinite number of effective gear ratios and the complex structure of the CVT drive that contains a hydrostatic unit and open planetary gear. ratio from idle to maximum in order to isolate the circumstances in which transmission noise occurred so its engineers could understand when it was most severe. Working together to get it right In October 2007, embarked upon the prototype phase for its first CVT. Totte Virtanen, a senior technical specialist for, states, This was a completely new product for us and we were determined to get it right. We had been using Siemens PLM Software tools for over 10 years and it just so happened that they were visiting when we started work on the unit. We noticed that we were experiencing gear whine and began discussing with LMSTM Engineering services whether we could work together to solve this problem. They already had experience in similar cases and had greater measurement, analysis and simulation capabilities than we did. This was a good start as diagnosed which gears were causing the problems and in what circumstances it was happening. LMS Engineering services then instrumented the gearbox on the inside to examine those problematic situations more carefully and identify the underlying dynamic phenomena of the gear whine. The first phase of the project involved carrying out engine run ups on a test rig. Using LMS Test.Lab software, employed a number of combinations, including driving the transmission LMS Engineering services approached this by making an operational deflection shape and alignment analysis of the transmission to observe how the parts inside the transmission moved in different operational conditions. This included placing 15 three-dimensional acceleration sensors and 17 position sensors inside the test transmission. In the end, more than 70 transducers sensors that can measure the position of the shaft and gear wheels at a micron level were deployed. This let LMS Engineering measure the pseudostatic alignment and vibration of several

3 We noticed that we were experiencing gear whine and began discussing with LMS Engineering services whether we could work together to solve this problem. They already had experience in similar cases and had greater measurement, analysis and simulation capabilities than we did. shafts and gears in operational conditions and, therefore, find a correlation between the physical movement of a shaft, the excitation of internal resonances and the noise generated by the transmission unit. LMS Engineering representatives focused on identifying the precise position of the gears in an operational gearbox. They needed to understand if the position of the gears changed as a result of the operating parameters. By using inductive sensors they could measure how far the gear meshing surfaces were away from the theoretical position. Based upon these measurements LMS Engineering was able to better understand the correlation between the alignment parameters and the noise. It was important that and LMS Engineering discuss upfront where the sensors should be placed. In the end, those sensors provided LMS Engineering We are very happy with the results. LMS Engineering services has unsurpassed skills in analyzing data and we are most certainly interested in future cooperation.

4 This was a completely new product for us and we were determined to get it right. We had been using Siemens PLM Software tools for over 10 years and it just so happened that they were visiting when we started work on the unit. with highly useful information about operational alignment change and structural resonance. This let them further understand the noise amplification mechanism and eventually it paved the way to a solution. Simulation leads to correct diagnosis Based upon these measurements, LMS now knew the real physical position of the meshing gears. The next stage was to conduct a simulation to calculate the transmission error (TE) of the meshing gear pair. For this LMS Engineering implemented precisely the same misalignment that was measured in the operational gearbox. Virtanen adds, When we looked at the measurement results, we found in certain conditions we had more misalignment and vibration amplification. Then with those measurements and simulation results we knew what the problem was: a combination of structural resonances excited by a larger than expected transmission error instigated by gear misalignment. In other words, the excitation of the gear unit was due to a misalignment of the output gear, resulting in the gear teeth contacting at an imperfect position. This, in turn, affected the bending of the teeth and increased the ripple on the gear ratio, thus generating noise. LMS Engineering diagnosed the underlying problem as being a relatively high movement of a particular shaft and proposed to add stiffness in the bearing supporting it. did just that, modifying the design, paying greater attention to tolerances and changing the structure to minimize misalignment. then built a prototype based on these modifications and the validation measurements that followed were conclusive: transmission noise was reduced by more than 3 decibels (db) in critical conditions, cabin noise by one db and cabin sound quality was also significantly improved. LMS Engineering provided added value by going inside the gearbox to pinpoint precisely the source of the noise, but some of the work, particularly the measurement preparation, was done by. The company modified its gearbox by identifying the locations where the transducers could be installed and then prepared a prototype by mounting all internal transducers at the identified locations.

5 Solution/Service LMS Engineering lms-engineering Customer s primary business is a manufacturer of tractors and agricultural machinery and forms part of the American agricultural equipment manufacturer AGCO Corporation. Founded in 1951, is a leading manufacturer and service provider in the Nordic countries and enjoys a growing reputation in South America. The bottom line: saving time spent eight weeks preparing, three weeks making measurements and 10 weeks performing analysis and simulation, so the entire project took about five months. Virtanen is clear on the value LMS Engineering provided in helping reach its goal of reducing transmission noise rather than simply insulating the sources. We saved at least one test cycle with new prototype parts, he states. This equates to at least three months and might well be a lot more. Time is money. We learned a lot through this project and now have much better capabilities to work with these issues. A sure market success launched its continuously variable transmission in October As part of an industry that is forever looking to make improvements to the bottom line, the introduction of CVT into s portfolio pleased its customers as well as facilitated cost savings. We are very happy with the results, concludes Virtanen. LMS Engineering services has unsurpassed skills in analyzing data and we are most certainly interested in future cooperation. Customer location Suolahti, Äänekoski Finland We saved at least one test cycle with new prototype parts. This equates to at least three months and might well be a lot more. Siemens PLM Software Americas Europe +44 (0) Asia-Pacific Siemens Product Lifecycle Management Software Inc. Siemens and the Siemens logo are registered trademarks of Siemens AG. D-Cubed, Femap, Fibersim, Geolus, GO PLM, I-deas, J T, NX, Parasolid, SIMATIC IT, Solid Edge, Syncrofit, Teamcenter and Tecnomatix are trademarks or registered trademarks of Siemens Product Lifecycle Management Software Inc. or its subsidiaries in the United States and in other countries. All other logos, trademarks, registered trademarks or service marks belong to their respective holders A5 5/17 P