Articles About noise
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In this paper, the influences of various gear parameters on the mesh stiffness are systematically investigated by using the finite element method. The comprehensive analysis shows that contact ratios are the key factors affecting the fluctuation value of mesh stiffness.
The automotive world faces a tremendous change. Autonomous driving and electrification are two big topics in this context that are pushing this change. The demand for higher comfort, higher safety and tightened environmental requirements drive as well the technological change from former mechanical actuations to electro-mechanical systems in new vehicles. This can be observed especially for braking and steering systems.
When it comes to a steel-gear mesh, there are several common standards and design rules on how to reduce noise emissions in the mesh. But if plastic gears are involved, this is no longer the case. The topic of this presentation is to highlight some of the differences between metal-and-plastic gear meshes, i.e. which design strategies can be stated as valid for metal as well as plastic and which are not?
Durability requirements must be balanced with the need for lightweight and low-cost solutions which meet noise and vibration targets whilst also exhibiting excellent efficiency.
Motion control systems often combine high power drive signals in close proximity (or even within the same cable) with lower level signals, like encoders. You will often see ferrite beads added around cables; their effectiveness in minimizing noise is greatly affected by how they are deployed. This involves which signals are grouped, what are the drive characteristics, and how shielding and grounding are handled in the system.
As NVH technology advances, so do the tools that allow engineers to study, test, and manufacture bearings capable of delivering high-performance and quality.
Rolls-Royce is pioneering the UltraFan engine family architecture containing a planetary gearbox in a power range of 15 to 80 megawatts. To increase the efficiency of the UltraFan, a planetary gearbox is introduced between fan and intermediate pressure compressor. This enables running the turbine to rotate faster and allows a reduced fan speed.
This work explains why some idler sets produce so much gear whine. While transmission error must be managed, there is another tool in the gear whine management toolbox.
Todayâ™s competitive industrial gear marketplace demands products with excellent reliability, high capacity and low noise. Surface-hardened, ground tooth gearing predominates, but the legacy tooth forms handicap further improvements in capacity and noise generation. Vehicle and aircraft equipment use tooth forms not found in the standard tables to achieve better performance â” with little or no increase in cost. This paper will propose adopting these high-contact ratio forms to industrial use.
For Mark Findlay of UK specialist driveline consultancy Drive System Design, reducing gear noise to suit the low noise levels in an electric vehicle cabin has meant throwing away the rule book.
I noticed it during my first assignment in a job shop. Maybe it was the gentle whir of a motor or the scratching sound of a grinding gear, but the factory floor boasted plenty of unique noises and sound effects.
Experienced operators can often tell if a machine is not working properly, on the basis that it does not â˜sound right.â™ The same principle can be applied â” using modern electronics â” to identify the exact cause of the problem. Sensitive accelerometers can detect and analyze the vibrations from industrial equipment, highlighting problems such as misalignment or bearing imbalance. The technique is known as vibration analysis. It can identify bearing failure in the very early stages, when there is a microscopic defect on the raceway, for example. The problem is that the identifying signal is usually drowned out in all the other noise emanating from the machine.
In the design of an automatic transmission gearbox, the variation of one parameter can result in different system performances due to the strong interdependencies among all components. For given transmission ratios, component lifetimes and safeties, or space restrictions, improvements in efficiency, noise, and weight can be achieved.
In planetary gear systems of high power density and high gear ratio, helical gears create undesirable tilting moments on the planet gears; therefore, spur gears are still preferred for planetary gears -- a special challenge with respect to noise. Specifically, the different behavior of planetary gears with sequential and symmetric gear mesh is explained in this paper.
Many of us have been there; the bearings had the correct preload. You know it, you were there, and you personally saw the measurements. Now, the testing is done and the preload is gone. Not a little gone, not sort of gone - gone, gone. Finger pointing ensues. Suppliers are dragged in by their wrinkly Polo collars. You know the drill. Losing preload in a tapered roller bearing (TRB) system over the life of your application can be a troublesome problem, particularly for gear sets that are prone to noise or severe applications that rely on a very rigid and stable system.
Global economic activity remains good -- noise about China slowing, notwithstanding -- and despite the ObamaCare debacle, non-Christmas-related consumer spending looks pretty good. Europe is still Europe and China continues to grow 7-8 percent -- even as the government seeks to clamp down on its own shadow banking system. And India remains a mess.
This paper presents a method for the acoustic analysis of electric motors in noisy industrial environments. Acoustic signals were measured via acoustic camera 48-microphone array, which has the capability to localize a sound (or sounds) source and, in turn, separate those sounds from intrusive background noise. These acoustic analysis results are then compared with vibration measurements; vibration monitoring is a well-known and established technique used in condition monitoring, and in this work vibration measurements were used as a reference signal for assessment of the value of the acoustic measurements. Vibration signals were measured by piezoelectric accelerometers. Two induction motor cases were examined â” a healthy motor case, and a combination of static eccentricity with soft foot case. As shown, acoustic analysis appears to be a valuable technique for condition monitoring of electric motors â” particularly in noisy industrial environments.
This paper presents an evaluation of measurements being taken on a 750 kW wind turbine gearbox being tested by the National Renewable Energy Laboratory (NREL). High-speed stage gears and bearings have been identified as critical components of the gearbox; during gearbox testing, these components were instrumented and tests were developed to evaluate loads on high-speed tapered roller bearings (TRBs). In this paper an advanced finite element-based contact modeling procedure has been applied to model the high-speed stage with the bearings fully modeled in order to evaluate strain levels. A major conclusion is that the strains of the slotted grooves are at such a level that they have acceptable signal-to-noise levels. This was verified by the results of the initial experiments presented here.
Experts gathered at the 9th CTI Symposium to discuss the challenges of reducing noise, improving energy efficiency and meeting the changing demands of the marketplace
Key technical drivers which can be addressed by advanced PM manufacturing technologies are, for example, the need for system downsizing in transmissions and differentials, the need for developing systems with higher power density and the strong NVH (Noise Vibration Harshness) requirements - especially for electrified transmissions or e-axle solutions.
News Items About noise
1 IMS Unveils Low Noise Planetary Gear Drives (February 13, 2008)
New Product Release IMS GEAR Planetary Gears Inc has recently completed the development and introduction of a new line of low noise ge...
2 Sakor Supplies Belt Noise Testing for Ford Motor Company (June 22, 2018)
Sakor Technologies Inc. has supplied an accelerated belt aging stand to Ford Motor Company for use in belt noise testing. The new preli...
3 Suhner Solves Noise Absorption for Power Seat (November 10, 2014)
Less noise, less vibrations, less distractions, more comfort; all this is required in today’s global automotive industry. The power...
4 Suhner's SU-Flock Silent Flex Shafts Reduce Noise in Power Seats and Sunroofs (May 1, 2015)
Flexible shafts do not create noise, but they can transmit vibrations from the power source, thus creating unacceptable sound levels. Suh...
5 AACs New Isolators Designed for Vibration and Noise (April 21, 2006)
A new series of 104 small square and round vibration isolators from Advanced Antivibration Components are designed for vibration and nois...
6 SKF Promotes Higher Speeds and Low Noise With Ball Screws (January 14, 2008)
SKF’s compact, long-lead ball screws with a rotating nut design allow the drive motor to move with the nut to reduce inertia, requi...