Application Watch: Gearmotor R&D steps up to meet robotics demand

Robotics continue to drive demand for key electromechanical components, such as gearmotors, as automation in the industrial and service sectors gains headway.

Even as the pandemic, in addition to the US-China trade war, impacted the automotive and the electrical/electronics markets, industrial robotics fared well enough to finish at about $10.6 billion in 2020, according to iGATE Research. And from 2021 to 2025, the sector is expected to surge on the basis of "cost reduction, improved quality, increased production and improved workplace health and safety."

Service robotics, meanwhile, posted $20.4 billion in 2020 and will keep growing during the forecast period thanks to increasing adoption in the medical, defense and agriculture industries, logistics, inspection and maintenance, rescue and security, construction and professional cleaning. The expanding use of personal and domestic robots for household tasks, entertainment and leisure is also a key catalyst in this segment.

The dynamism of the robotics industry can be seen in ongoing research too. The International Federation of Robotics (IFR) has released an updated report on government-funded R&D plans recalibrated for post-pandemic reopening. These programs include Made in China 2025, Japan's New Robot Strategy, the Intelligent Robots Development and Distribution Act in Korea, Horizon Europe, Germany's High-Tech Strategy 2025 and the US' National Robotics Initiative.

There have also been notable recent mergers and acquisitions in the robotics space. In addition to 89 such transactions in 2019, about 60 were recorded the following year, according to an article by Eugene Demaitre in The Robot Report. Based on this trend, Analytics Insight is betting on an accelerated pace for such consolidations in 2021, which has already seen quite a few. They include the acquisition by Accenture of Pollux, Verizon of incubed IT and Teledyne of FLIR.

All of its own

In China - the largest robotics market with the fastest growth in total sales, according to IFR - the number of installations is the highest in the world. In 2019, up to 140,500 industrial robots were installed, far exceeding Japan's 49,900 units. However, in terms of robot density, China tallied 187 robots per 10,000 workers that year, compared to 855 in world leader South Korea and 364 in second-placed Japan, according to Statista's report based on IFR data.

Still, industry analysts are not discounting a key role in robotics for China. In its survey of the top countries in robotics implementation in 2021, IFR describes China's robot density as a development that "continues dynamically."

Taking new patents as a gauge, the country is said to have accounted for 44 percent of applications published worldwide in 2019, according to HRG International Institute of Research and Innovation, as quoted by Robotics & Automation News.

By market scale, China's robotics industry reached $10.46 billion in 2020, rising 17.2 percent YoY, according to market research firm China Industry Information. By application, industrial robots had a 66 percent share, service robots 25 percent and special robots the remainder. In 2021 and 2022, this upward trend is predicted to continue at a rate of more than 15 percent.

Gearing up for growth

Chinese gearmotor manufacturers interviewed by Global Sources Electronic Components anticipate total sales will be at the same high level of growth as robotics in the next two years. This is based on the key components that account for 70 percent of robot production costs and gearmotors' sizeable portion thereof. Breaking those costs down, gearmotors have a 35 percent share, servo motors 20 percent and controllers the remainder.

For this application, gearmotors have to be small and lightweight but deliver high-power and easy-control performance. In these aspects, they are different from conventional gearmotors for general use. Chinese companies have been working to improve their manufacturing capability to catch up with foreign counterparts in terms of high precision, long operating life span and miniaturization.

China's current range of robotics gearmotors based on the speed reducer used consists of RV, harmonic and planetary types. The second is widely adopted now, but RV types are expected to dominate in the coming years and are currently a development priority. This is because such motors offer high precision, efficiency, stability and shock resistance, as well as an extended life span. One supplier that has now introduced RV gearmotors is Beijing Chietom. Its CRD series is equal in performance to servo motors, boasting precision of less than 1 minute of arc and high overload protection at maximum five times of rated torque.

In production, expansion is also an objective for most manufacturers. At Shenzhen Yunhongda Motor Co. Ltd, gearmotors make up half of output but only 10 percent is for robotics. In 2020, the company increased factory area by 10,000sqm andinvested $1.47 million in new equipment, anticipating an uptick of more than 10 percent in production due to high demand in the next two years.

China's manufacturing pool for gearmotors has more than 100 companies, including those with foreign investment. All have the capability to cater to robotics applications. Leaderdrive, Zhongda Leader and Shenzhen Zhaowei are some of the major suppliers.

Over half of these manufacturers are located in Suzhou, Nantong, Wuxi, Ningbo and Shanghai, with the rest in Shenzhen, Dongguan, Beijing and Chengdu.

Typical robotics gearmotors

Planetary gearmotors currently lead shipments of Chinese manufacturers, but this will change as more RV and harmonic types will be offered in the years ahead.

Commonly available are motors with rated power of 5 to 50W, speed of up to 2,000rpm and torque of 1gf•cm to 50kgf•cm. Most units have a reduction ratio of 1:1,000 to 10,000. They are CE-approved, UL-listed and RoHS-compliant.

The key materials used include copper, shafts, bearings, flanges and cases, which may be domestically sourced or imported. Speed reducers are usually from foreign providers such as HDS of Japan.

Copper costs rose in 2020, leading most manufacturers to raise gearmotor prices by 5 to 10 percent. Overall outlay is expected not to fluctuate much the rest of 2021 and keep product quotes stable.

1,890Nm planetary gearmotor

Rated at 3.1V, 2.8A, this 23HD5233 gearmotor from Guangzhou Ruibao Electrical Co. Ltd has a planetary gearbox, 1,890Nm motor holding torque, 13:1 reduction ratio and -20 to 50 C operating temperature.

An order of at least one unit is for delivery within 10 days.

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Gearmotor has 20 or 28g.cm torque

Shenzhen Yunhongda Motor Co. Ltd's FT-46SGM370 gearmotor has 20 or 28g.cm torque, and 4,200 or 10,300rpm load and 5,000 or 12,000rpm no-load speeds. The rated voltage is 6 to 12V, and current 240 or 520mA with load and 45 or 90mA with no load. Output power is 0.88 or 2.96W.

The 1,000-unit minimum order requirement has a lead time of 10 days.

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Gearmotor, 3 to 40kg.cm on-load torque

Available in 12V or buyer-specified voltage and 550, 560 or 580mA current with load, this KM-42F540-8828 gearmotor from Shenzhen Kinmore Motor Co. Ltd has 3 to 40kg.cm load torque, and 6.3 to 95rpm speed with load and 7.5 to 113rpm with no load. Reduction ratio is 1/37, 1/189, 1/244 or 1/554.

The minimum order is five units for delivery within 15 days.

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Harmonic gearmotor, 3.8 to 140Nm torque

The LFS Series gearmotor from ZJTEX Electric Group Co. Ltd has 3.8 to 140Nm torque, 3.8 to 7.8Nm load capacity and 3,000rpm input servo motor speed. This harmonic-type unit suits robotics applications, automation equipment and CNC machines.

The supplier requires a minimum order of 1,000 units. Delivery is within 30 days.

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