In the entire supply chain of humanoid robots, if asked which component is the most headache-inducing, the answer is highly likely the planetary roller screw. It is not because of a highly complex structure, but because it is expensive, difficult to manufacture, and has been bottlenecked by overseas enterprises for decades. How expensive is it? The quoted price for a single imported unit often exceeds tens of thousands of RMB. A single Optimus robot requires 10 to 14 of them, accounting for 15% to 25% of the total cost of the machine. Globally, four companies—Rollvis and GSA from Switzerland, Bosch Rexroth from Germany, and Ewellix from Sweden—have long occupied nearly 80% of the global market share. Buyers have no bargaining power, and delivery schedules are entirely at the mercy of suppliers. The turning point occurred in the past two years. Domestic manufacturers have slashed prices from the ten-thousand-yuan level directly down to 499 RMB, a drop of more than an order of magnitude. Behind this price collapse are three forces working simultaneously: technological breakthroughs, equipment localization, and capacity expansion.
1、From Rotation to Linear Motion: How Does It Work? Motors output rotary motion, but robot joints require telescopic pushing and pulling. A 'translator' is needed in between, and the planetary roller screw is exactly this translator. Its structure is not complex: a threaded screw is centered, surrounded by a nut, with a ring of rollers sandwiched in between. The rollers perform planetary motion around the screw, transmitting force through the meshing of threads—hence the name 'planetary roller'. To understand why it outperforms the common ball screw, the key lies in the contact method. Ball screws use steel balls to transmit force, resulting in point contact between the balls and the threads, which means a very small load-bearing area. In contrast, planetary roller screws use thread surfaces to transmit force, where the contact is a line or even a surface. With a larger load-bearing area, various performance metrics naturally diverge: load capacity increases by 3 to 6 times, service life extends by 10 to 15 times, volume shrinks by about one-third under the same load, and transmission efficiency exceeds 90%. For humanoid robots, the linear actuators in the shoulders, elbows, hips, and knees must output high thrust in confined spaces while withstanding impact loads from high-frequency forward and reverse rotations. The load capacity of ball screws is insufficient, and hydraulic solutions are too bulky. The planetary roller screw perfectly strikes a balance among load capacity, precision, volume, and cost.
2、Three Checkpoints: Equipment, Materials, and Processes The persistently high price stems from the extreme difficulty of manufacturing, which is not an issue with a single process but a barrier set across the entire chain. The first checkpoint is equipment. Machining high-precision threads is inseparable from thread grinding machines. This field has long been dominated by Mitsui Seiki of Japan and SMS of Germany, with single-unit prices in the tens of millions of RMB and long delivery cycles. Domestic equipment still lags in precision retention and machining stability. When equipment is controlled by others, the ceiling for capacity expansion is suppressed. The second checkpoint is materials. Screws and rollers require special alloy steels (such as 50CrMo4 and GCr15), with extremely strict requirements for purity, hardness gradient, wear resistance, and consistency of heat treatment processes. Minor fluctuations in material performance across different batches will directly affect the yield rate of finished products. The third checkpoint is assembly and process experience. Precision grinding of multi-start threads, planetary arrangement design of rollers, and the selection and assembly of parts—there are no shortcuts in these links. It all relies on the accumulated process experience on the production line day by day. The real challenge does not lie in making the first qualified sample, but in ensuring that the precision and performance remain stable when producing the ten-thousandth unit.
3、The Landscape Is Shifting For a long time, the planetary roller screw has been a 'small but expensive' niche market, with demand concentrated in aerospace, military, and high-end machine tools, with annual consumption of only a few thousand to tens of thousands of units. European companies have lived comfortably and naturally lacked the motivation to expand production on a large scale. However, humanoid robots have broken this balance. When the order of magnitude of demand jumps from 'tens of thousands' to 'millions', the capacity of overseas manufacturers simply cannot keep up. The global market size was about 1.27 billion USD in 2022, and according to industry estimates, by 2030, humanoid robots alone will add 22.96 billion RMB of market space, with an annual growth rate exceeding 50%. Currently, the localization rate of planetary roller screws in China is less than 20%, and products are mostly concentrated in the low-to-medium specification segments—the larger the gap, the greater the opportunity.
4、Ten Domestic Enterprises: Each With Its Own Strategy Shuanglin Shares—The Price Breaker In 2025, it fully acquired Wuxi Kezhixin, bringing domestic scarce high-precision screw grinding machine technology into its fold, forming a closed loop of 'self-developed equipment + self-produced products'. In early 2026, a 100,000-unit production line will be put into operation, with C3-grade screws priced at 499 RMB, less than one-tenth of similar international products. The self-developed grinding machine cuts the investment per unit from the tens of millions level down to 3 million RMB, compresses the processing time per unit to 30 minutes, and pushes the yield rate to 90%. A subsequent plan to expand production to one million sets is also in progress.
- Zhejiang Xinjian Transmission—The Closest to Tesla With over 20 years of deep cultivation in transmission components, it is a 'Little Giant' enterprise specializing in new and unique fields. The industrialization project for an annual production of one million screws is in its final stages, and it is sprinting for an IPO on the STAR Market, planning to raise over 2.8 billion RMB. It has entered the Tesla Optimus supply chain, covering all 14 screw components per robot. It has formed a strategic alliance with Wuzhou Xinchun, collaborating with a clear division of labor.
- Wuzhou Xinchun—Bearing Technology Feeding Back into Screws With profound accumulation in the pre-grinding process of bearings, it launched a 1.5 billion RMB screw investment project in 2025, planning an annual production of 980,000 sets. Its role is positioned more upstream—supplying semi-finished screws to Zhejiang Xinjian Transmission, forming a partner model of 'Wuzhou handles the front-end, Xinjian handles the back-end'. The main bearing business provides stable cash flow, while the screw business offers elastic growth.
- Hengli Hydraulic—Cross-Dimensional Entry by a Hydraulic Leader In 2021, it raised 1.4 billion RMB through a private placement to layout linear actuators, transferring decades of precision machining and heat treatment capabilities in the hydraulic field to the screw track. Five products have been finalized, with existing capacity of about 100,000 units per year, targeting an expansion to 500,000 units by 2027. Samples have been submitted to Tesla, and small-batch orders have been received. Over 30 production lines will be implemented in the second half of the year. With abundant funds and a solid process foundation, its latecomer advantage cannot be underestimated.
- Qinchuan Machine Tool—Building Its Own Screws with Its Own Machine Tools As a time-honored machine tool enterprise, it comes with in-house thread grinding machine R&D capabilities, giving it a very high starting point in precision thread machining. While others spend huge amounts to buy imported equipment, it can manufacture its own, making the investment threshold and delivery cycle more advantageous. There is a natural synergy between the main machine tool business and the screw business.
- Nanjing Craftsmanship—The 'Master Craftsman' in the Industry Founded in 1952, it has been deeply engaged in the field of rolling functional components for over 70 years and is one of the few domestic enterprises capable of developing and mass-producing planetary roller screw assemblies. Its products mainly target the military and high-end CNC machine tools, with profound process heritage. Although not listed, in terms of technological accumulation, it belongs to the first tier among domestic peers.
- Best Group—Originating from Precision Grinding, Heading Straight for the Highest Precision Starting from turbocharger components, it has struggled and grown in the precision machining field for 20 years. It has produced C0-grade samples—the highest precision grade in the industry, with errors controlled within 1.5 microns. Products have been sent to Tesla and Huawei for verification. The static load capacity and lifespan of its inverted planetary roller screw products reach 3 times and 15 times that of traditional ball screws, respectively, while covering three structural forms.
- Beite Technology—The Fastest in Capacity Expansion Rooted in automotive precision manufacturing, it is simultaneously building factories in Jiading, Kunshan, and Thailand. The Kunshan base will be put into production in 2026, with an annual capacity of 2.6 million sets; the Thailand base plans for 800,000 sets, totaling over 3.4 million sets across the three locations. Among all domestic players, Beite's capacity planning figures are the most ambitious.
- Dingzhi Technology—Focusing on the Micro Niche Focusing on miniature screw products, it mainly supports dexterous hands and fine joints. The precision requirements for miniature transmission are also at the micron level, and the technical threshold is not low. However, competition in this niche track is relatively mild, and the first-mover advantage is obvious. It has established cooperation with multiple dexterous hand manufacturers, achieving precise positioning.
- Changsheng Bearing—Entering the Roller Screw Market via Precision Rollers The core competency of bearing enterprises is precision roller manufacturing, and rollers happen to be one of the core components of planetary roller screws. Changsheng uses this as an entry point into the screw supply chain, and its products have entered the verification stage in some robot projects. The main bearing business is stable, and screws represent incremental expansion. The transformation path is clear, but integration capabilities need to be strengthened.
5、The Capacity Race Has Just Begun Currently, the global annual shipment of humanoid robots is about 10,000 to 20,000 units, with a screw demand of only over 100,000 units, while the global effective capacity is less than one million units—the current contradiction is supply falling short of demand. But the wind is changing: the planned capacity of just Shuanglin, Beite, and Xinjian totals over 5 million sets. Adding other players, the total domestic planned capacity is approaching the ten-million level. If global humanoid robot sales reach 1.3 million units by 2030 as predicted by institutions, calculating at 14 screws per unit, the screw demand will be about 18.14 million units. At that time, the supply and demand balance is highly likely to shift from 'tight' to 'balanced', and a price war will be hard to avoid. This is a typical prelude to an elimination game. Dozens of enterprises crowd into a track with short-term demand of only a few hundred thousand units. In three to five years, it is highly probable that only three to five will remain standing. The survivors will reap the rewards, while the eliminated will exit. From the second half of 2026 to 2027, the sample verification results of Best Group, the capacity ramp-up of Hengli Hydraulic, and the yield rate ramp-up data of Shuanglin will jointly determine who can stay at the table until the end.
This article is compiled based on publicly available network information and is for reference only, not constituting investment advice.