Domestic precision planetary gear reducers achieve technological breakthroughs, marking China's entry into the high-end equipment field through domestic substitution

Writer：tilireducer Time：2026-09-28 14:34:30 Browse：171℃

In 2024, the sales proportion of domestically produced industrial robots exceeded that of foreign brands for the first time, and the market share of domestically produced industrial robots continued to climb in 2025. However, behind the prosperity, high-end precision reducers for joints remain the core components that restrict domestically produced robots from advancing towards high-end scenarios. In high-end application scenarios such as automotive welding, high-precision assembly, and heavy-load handling, there are stringent standards for the long-term operational stability and positioning accuracy of reducers, which typically need to achieve an accuracy within 60 arc seconds (1 arc minute).

For a long time, high-end products that meet this specification have been predominantly occupied by foreign brands. The seemingly small angular value of 60 arc seconds has become a clear dividing line between the mid-to-low-end and high-end reducer markets, representing a performance threshold that domestic manufacturers must overcome to enter the high-end arena.

The angular second is an angular unit used to measure the deviation of rotary transmission. A circumference is 360 degrees, 1 degree equals 60 angular minutes, and 1 angular minute equals 60 angular seconds. 60 angular seconds represents that the angular deviation at the output end of the reducer cannot exceed 1/60 degree during one rotation. This threshold is not a single parameter, but a comprehensive manifestation of a whole set of precision manufacturing systems, with multiple layers of technical barriers behind it.

At the design and material levels, achieving high torque density and high rigidity in a compact space requires a profound accumulation of meshing dynamics theory. The alloy materials selected for core components such as gears and flexspline, as well as heat treatment processes such as carburizing and quenching, and vacuum ion nitriding, directly affect the accuracy and service life of the reducer.

At the manufacturing process level, the overall precision relies on the ultra-high processing standards of core components. Without high-end processing machines and long-term process accumulation, it is difficult to consistently produce components that meet standards. In addition, there are structural route barriers. Simply imitating the architecture of mature overseas products is difficult to simultaneously achieve high precision, high rigidity, and long lifespan. Innovations in the underlying structure are the key to breaking through these barriers.

Classification of Precision Reducers and Layered Demand for Robot Scenarios According to the general industry classification standards, precision reducers generally refer to products with an accuracy of ≤7 arc minutes. Backlash (backlash) is the core factor determining accuracy. Backlash can cause backlash deviation between the input and output ends, directly affecting the positioning accuracy and repeatability of the equipment. Backlash, which refers to the actual motion deviation between the input shaft and the output shaft of the reducer, is a key indicator for evaluating the positioning capability of the equipment. Breaking through 60 arc seconds! Domestic Precision Reducers Break into the High-end Market According to the meshing mode of the main transmission, precision reducers are mainly divided into four categories. Precision cycloid reducers, represented by RV reducers and cycloid pin wheel reducers, have strong load-bearing capacity and impact resistance, but their disadvantage is complex structure and high manufacturing cost. Harmonic reducers rely on the elastic deformation of the flexspline to transmit power, with high accuracy and compact size, but their rigidity is relatively weak, making them difficult to withstand heavy loads. Precision planetary reducers have high transmission efficiency, but their traditional structure has shortcomings such as small single-stage reduction ratio and relatively low accuracy. Precision worm reducers, including roller cam reducers, worm gear reducers, etc., have decent accuracy, but their volume is relatively large and torque density is relatively low.

Industrial robots with different loads and processes have distinct requirements for the torque, rigidity, and transmission accuracy of the reducers, highlighting the characteristics of tiered demand.

For six-axis robots weighing less than 10kg, priority is given to both volume and precision. Most of their six joints utilize harmonic reducers, suitable for high-precision motion control within the confined installation space of light-load robots. For medium-load six-axis robots weighing between 10-50kg, which are commonly used for handling automotive parts and processing metal products, both load capacity and precision are considered. Typically, a combination of harmonic reducers and RV reducers is employed. To ensure flexibility, harmonic reducers are often chosen for the end-effector joints.

Heavy-duty six-axis robots weighing over 50kg have higher requirements for load-bearing capacity and accuracy retention. They are typically equipped with RV reducers, which rely on high rigidity to withstand substantial radial and axial loads, ensuring stability during heavy workpiece operations.

SCARA robots weighing 20kg or less have extremely high requirements for positioning and repeatability accuracy. Harmonic gear reducers are commonly used for rotary joints, and planetary or belt drives can be selected for the Z-axis up-down motion. Parallel Delta robots feature high speed and high rigidity. Planetary gear reducers with small reduction ratios are often used for the base joints to meet the requirements of low-inertia high-speed motion, and cycloid or harmonic gear reducers are also selected in some scenarios. Planetary gear reducers are commonly used for additional axes at the end, and harmonic gear reducers can be configured for the end joints to enhance positioning capability in high-precision assembly conditions.

Overall, the mainstream applications of industrial robots are harmonic reducers and RV reducers. Traditional planetary reducers are limited by their precision and miniaturization capabilities, and are less commonly used in the robotics field. However, foreign brands such as Wittenstein Alpha series and Germany's MeliorMotion's PSC precision planetary products, with precision up to within 60 arc seconds, occupy a place in the high-end industrial robotics, machine tool turntables, and semiconductor precision equipment markets.

However, the high prices and long delivery cycles of such imported products contradict the rapidly expanding domestic demand for robotics. A few domestic manufacturers have broken away from traditional planetary transmission concepts and relied on self-clearing technology to enhance the precision, rigidity, and accuracy lifespan of planetary reducers, applying these products in the fields of industrial robots and machine tools. Breaking through 60 arc seconds! Domestic precision reducers have shifted gears to tackle high-end self-clearing technology, cracking the underlying bottleneck of accuracy degradation. Traditional precision reducers have an inherent pain point: continuous wear of gear meshing will continuously expand the backlash, leading to increased lost motion, continuous degradation of positioning accuracy, and ultimately affecting the quality of equipment processing and shortening the overall service life of the machine. The emergence of self-clearing technology provides a fundamental solution to this problem. Unlike traditional passive backlash structures, self-clearing reducers are equipped with adaptive adjustment mechanisms that can automatically compensate for backlash when gears wear, maintaining stable transmission accuracy over the long term and extending the accuracy retention lifespan in principle.

The current mainstream self-lubricating technology falls into two main categories. One is the conical gear self-lubricating structure, represented by the MeliorMotion PSC series, which relies on conical planetary gears paired with a spring pre-compression mechanism to achieve automatic wear compensation, maintaining accuracy within 60 arc seconds. Europe and China are the brand's primary global markets. However, in the face of fierce price competition in the domestic robotics industry, the product's high cost has significantly restricted its market expansion.

The other is the original self-eliminating backlash route of the modified planet carrier developed by domestic manufacturers, represented by the H3K series planetary gear reducers from Aici Technology. The product adopts an innovative structure featuring a deformable planet carrier paired with a self-locking cone sleeve. When the tooth surface experiences wear or initial machining errors, the planet carrier's elastic system actively adjusts the position of the planet gear, ensuring continuous backlash-free meshing between the planet gear and the inner gear ring.

The H3K-K series angle transmission accuracy of Aici Technology can be controlled within 50 arc seconds, with torsional rigidity and main bearing overturning rigidity superior to those of robot reducers of the same level. The transmission efficiency is as high as 90%, combining the high precision of harmonic gears with the high rigidity and large torque of RV reducers. Taking the 80T model as an example, it has a maximum outer diameter of 220mm, backlash of 15 arc seconds, rated torque of 800 Nm, repeatability within 4 arc seconds, and end face and radial runout up to 0.002mm; torsional rigidity of 380 Nm/arc minute, instantaneous maximum allowable torque of 3200 Nm, and accuracy retention life up to 20,000 hours. Breaking through 60 arc seconds! The domestic precision reducer's shift to high-end self-eliminating backlash technology has also extended to the harmonic gear reducer track. Aici Technology has developed a dual-flexspline self-eliminating backlash harmonic gear reducer, relying on the structural design of inner and outer flexsplines and a limit ring to suppress backlash over the long term, with a lost motion about half that of foreign harmonic gear reducers of the same level. Facing the lightweight requirements of humanoid robots, the company has also developed a self-eliminating backlash plastic harmonic gear reducer, which is injection molded using PEEK material and weighs only one-third of traditional metal harmonic gears. Relying on the backlash-eliminating structure to compensate for material wear, it solves the industry pain point of rapid accuracy degradation in plastic harmonic gears.

Crossing the threshold of 60 arc-seconds, domestic components have embarked on a breakthrough in a new direction. The technical threshold of 60 arc-seconds has set the entry criteria for the high-end application market. Scenarios such as five-axis linkage machine tool turntables and swivels, semiconductor precision equipment, automotive spot welding and engine block assembly, aerospace final assembly, surgical robots, etc., are typical working conditions that require both high precision and high rigidity. The upper limit of precision for traditional RV reducers is generally around 60 arc-seconds. Although harmonic reducers can achieve high precision, their flexible gears are prone to fatigue fracture and lack rigidity, making them unsuitable for heavy-load working conditions. Self-backlash-eliminating reducers precisely fill this market gap.

In the past, domestic reducer manufacturers mostly followed and chased after mature foreign technology routes, easily hitting the performance ceiling and being trapped in the low-end and mid-range market for a long time. 60 arc seconds is not only a technical indicator, but also a "gantry" for high-end manufacturing and a market moat. Successfully crossing this threshold means that the enterprise has mastered high-end capabilities across the entire chain of design, materials, and processing and manufacturing, entering the high-end equipment market with high added value and rigid demand; failure to break through means that the enterprise can only compete in the low-price, low-end and mid-range market.

As local enterprises such as Aici Technology continue to delve deeply into underlying technologies, original technological routes like self-clearing backlash are gradually maturing, providing domestic precision reducers with opportunities for breakthroughs in new directions. The market landscape of high-end precision reducers is undergoing changes, and the boundaries of domestic substitution are continuously extending from traditional mid-to-low-end scenarios to core high-end manufacturing sectors such as machine tools, semiconductors, and humanoid robots.

Breaking through 60 arc seconds is not just an improvement in product performance, but also a crucial battle for domestic core components to break away from low-end competition, promote industrial upgrading, and ensure the independent security of the domestic supply chain.