The Importance of Quiet Gearboxes in Industry 4.0
In the fast-paced world of Industry 4.0, industrial robotics have become a vital cog in manufacturing processes. The increased prevalence of these machines, although providing numerous benefits, has highlighted a crucial yet often overlooked aspect – noise pollution. As we transition towards a future where collaborative robots, or ‘cobots’, working alongside humans are commonplace (with a predicted 50% market growth in 2023 according to the International Federation of Robotics’ study) , ensuring a safe, quiet, and comfortable industrial environment is imperative. This is where noise control, particularly in gearboxes, comes into play.
In this article, we will explore the impact of noise in industrial settings, understand the crucial role of gearboxes in noise generation, delve into the technical aspects of noise measurement and control, compare noise levels among different gearboxes, and highlight a future-proof solution for silent and efficient operations.
The Unseen Ripple Effects of Industrial Noise
Before delving into the technicalities of noise, let’s consider an everyday example: a simple coffee grinder. When grinding coffee beans, the machine generates noise as its gears mesh and turn. This noise may seem trivial, but scale that up to an industrial setting with hundreds of machines working simultaneously, and it becomes a significant issue.
The high-intensity noise generated in industrial settings poses significant health risks to workers. Prolonged exposure to noise levels exceeding 80 dB, common in many industrial settings, can lead to noise-induced hearing loss (NIHL), a common occupational disease. Unfortunately, many workers underestimate this risk until it’s too late, as the damage is gradual and often painless. The use of personal protective equipment (PPE), such as earmuffs and earplugs, is a standard preventive measure, but it’s often inadequate. In many cases, workers have to resort to hearing aids after suffering significant hearing loss.
The European Agency for Safety and Health at Work published a report detailing the extent of noise-related health issues in Europe. According to the report, 28% of workers in Europe are exposed to noise levels for at least a quarter of their working time, causing 22% of them to report hearing difficulties. These figures underline the urgent need for effective noise control solutions in industrial settings.
Sound of Silence: The Industrial Noise Control Market
In light of the growing concern about noise pollution, the industrial noise control market has been expanding rapidly. According to a report by Allied Market Research, the global industrial noise control market size was valued at $744.4 million in 2019 and is projected to reach $1,153.6 million by 2027.
The demand for effective noise control solutions is fueled by stringent regulations from occupational health and safety authorities, growing awareness among employers about worker health and well-being, and technological advancements in noise control methods. Long-term exposure to high levels of noise can lead to severe health effects, including hearing loss, cardiovascular diseases, stress, and sleep disturbances, among others.
Imagine the soundscape of a busy manufacturing facility: the high-pitched noises of machines drilling, hammering, or welding, the buzzing of forklifts and conveyor belts transporting materials back and forth, or the humming chatter of workers. This cacophony of noise is what many people deal with every day at work.
Cutting Through: The Science Behind Sound
Noise, scientifically, is undesired or disturbing sound. It’s characterized by its frequency (measured in hertz, Hz) and intensity (measured in decibels, dB). Our ears can perceive frequencies ranging from 20 Hz (the low hum of an industrial fan) up to 20,000 Hz (the high pitch of a dog whistle). As for intensity, the decibel scale is logarithmic, meaning that an increase of 10 dB equates to a tenfold increase in sound intensity.
It’s essential to understand that not all frequencies contribute equally to perceived noise. Certain frequencies, particularly those that coincide with the natural resonant frequencies of buildings or other structures, can be especially troublesome.
To illustrate, imagine two people having a conversation in a bustling café. The background chatter, clanging dishes, and hissing espresso machines create a broad spectrum of sound frequencies. However, if one person speaks in a pitch that matches the café’s resonant frequency, their voice will stand out amidst the cacophony. This principle holds true for industrial noise too: reducing these key frequencies can significantly reduce overall noise.
On the decibel scale, typical conversation level is around 60 dB, a vacuum cleaner runs at 70 dB, city traffic noise hovers around 85 dB, while a jet takeoff can reach a staggering 140 dB. The ‘3dB trading effect’ means that a 3 dB increase in noise equates to doubling the sound pressure level and hence the risk of damage to hearing, assuming the exposure time remains constant. Conversely, the ‘5dB exchange rate’, as per the OSHA standard, implies that a 5 dB increase halves the permissible exposure time.
Causing a Racket: Gearbox Noise Importance and Comparison
A study from 2019 found that when asked to perform a synchronous task with a robot, participants were relying on the actuator or gearbox noise more than visual cues from the robot. This highlights the importance of auditory signals in human-robot interactions, be it for rhythmic interactions or safety procedures. NASA and the U.S. Army were also focused on reducing gearbox noise, one example being in helicopter cabins, where noise measured over 100 dB. Noise should thus be minimized to a level where it can safely and comfortably facilitate interactions.
There’s a wide variety of gearboxes employed in the industrial sector, each with their noise characteristics. Traditional gearboxes, such as spur, helical, or worm drives, can produce substantial noise due to their mechanical interactions, often reaching levels of up to 85 dB and beyond. This noise level is comparable to heavy city traffic or a freight train, a level that can be harmful with prolonged exposure.
Spur gears, while simple and cost-effective, generate high noise levels due to their straight-cut tooth design leading to sudden load transfers. Helical gears are quieter due to their angled teeth, allowing for gradual load transfer, but they still produce significant noise.
On the other hand, strain wave gearboxes, known for their compactness and high torque capabilities, are quieter due to their unique operating principle. However, their complex design leads to higher costs and potential reliability issues.
In contrast, the Archimedes Drive speed reducer by IMSystems generates noise levels under 50 dB, with minimum levels going below 37 dB, and a frequency mimicking that of white noise. For perspective, this level of noise is equivalent to a quiet household or the sound of gentle rain, making it a much more comfortable experience for human ears. By comparison, under the same conditions the “quiet” equivalent strain wave gear speed reducer produced noise levels up to 65 dB, equivalent to the sound of moderate traffic.
Find an overview of the internal testing results from an acoustic chamber in Table 1 below.
A Future-Proof Solution: Make Some Noise for the Archimedes Drive
The Archimedes Drive speed reducer boasts a revolutionary compound planetary traction drive that operates smoothly and silently. During rigorous internal testing This ingenious design allows for a substantial reduction in noise while providing exceptional performance characteristics. The drive offers zero backlash, high efficiency, and excellent torque capacity, all within a compact and lightweight design.
The Archimedes Drive, therefore, provides an effective and efficient speed reducer while ensuring a comfortable and safe working environment. As the industry moves towards a future where noise control will be as critical as speed and efficiency, gearboxes like the Archimedes Drive will be instrumental in driving this transformation.
References:
- Allied Market Research. (2020). Industrial Noise Control Market by Product Type, Material Type, and Application: Global Opportunity Analysis and Industry Forecast, 2020–2027. Portland, OR: Allied Market Research. URL: https://www.alliedmarketresearch.com/industrial-noise-control-market-A08480
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