Lightweighting is a key technological focus in the automotive industry. Particularly under the current “carbon peak and carbon neutrality” strategy, reducing material usage, minimizing energy consumption, enhancing power performance, extending service life, and improving load-bearing capacity are all crucial pathways to achieving energy efficiency and environmental protection in vehicles. Commercial vehicles, as means of production, are central to energy conservation, emission reduction, and the development of a low-carbon economy—indeed, the carbon emissions from a single commercial vehicle are 20 times those of a passenger car. On the global automotive industry’s journey toward achieving the “dual carbon” goals, commercial vehicles represent the linchpin for making breakthroughs. In this new product R&D and project development endeavor, the universal joint factory has demonstrated exceptional capabilities in technological innovation and quality assurance. The company’s independently developed, globally advanced, high-strength, lightweight universal joint products for commercial vehicles have been supplied to several major international strategic customers, yielding remarkable economic and social benefits.

Pursue the pinnacle of quality, explore the limits of performance.

Five years ago, the U-Joint Factory proposed a product R&D direction of “Pursuing Peak Quality and Exploring Performance Limits.” Three years ago, this was further refined into product technologies characterized by “lightweight, compact, minimal, and long-lasting,” as well as manufacturing technologies focused on “refinement, excellence, and extreme precision.” Being lighter, stronger, and more durable is at the heart of it all. “For the technical team at the U-Joint Factory, our goal is to take a global perspective and strive for technological breakthroughs and leadership in development. No matter how challenging the road ahead may be, no matter how much effort it takes, we cherish this mission deeply and remain steadfast—never letting go of our commitment!” said Niu Jie, the technical director of the U-Joint Factory.

To this end, the technical team continuously enhances the strength of cross shafts and bearing life by researching new designs, new processes, and new materials, thereby achieving both high strength and lightweight construction. At the same time, they have also succeeded in replacing larger-sized universal joints with smaller ones in specific vehicle models (i.e., miniaturization), thus avoiding the development of larger-sized universal joints that consume more materials and energy. By standardizing and serializing their products, they provide customers with value-added services that address challenges related to service life, cost, and energy consumption, helping universal joints and drive shafts contribute to the goals of “carbon peak” and “carbon neutrality” in the commercial vehicle sector.

The new-generation high-strength, lightweight universal joint product developed by the universal joint manufacturer features an innovatively optimized cross-shaft body structure, enabling extreme strength design for the entire cross-shaft assembly. This allows the new-structure product to match the load-carrying capacity of conventional large-specification products while using smaller specifications, achieving maximum weight reduction—a crucial prerequisite for miniaturizing the entire drive shaft assembly. Furthermore, the manufacturer has introduced innovative designs for bearing structures, including wear-resistant and vibration-absorbing shims as well as a ventable sealing structure, significantly extending the service life of the universal joint bearings. Additionally, a new high-strength, lightweight material for the cross-shaft has been innovatively developed, dramatically enhancing the fatigue strength of the cross-shaft. A new material for the bushings has also been developed, effectively improving both the wear resistance of the raceway surface and the core toughness of the component.

This product’s related technologies have resulted in the establishment of four enterprise standards, and the company has obtained one design patent, five utility model patents, and six invention patents. Additionally, three papers have been published in core journals. Overall, the technology is at a leading level among similar domestic products, and in terms of high-strength, lightweight technology for heavy-duty truck universal joints, it has reached an advanced international standard. The technology has been listed as a scientific and technological achievement of Zhejiang Province and has received the Zhejiang Provincial Mechanical Industry Science and Technology Award.

Not only new products, but also new standards.

As a type of rolling bearing, the durability of universal joint bearings is a complex, interdisciplinary technical indicator involving the intricate interaction among solid, liquid, and gas phases. It also represents the technological core of universal joints, and sealing technology is one of its most critical core technologies.

Breaking away from traditional sealing design approaches and innovating sealing technologies have become major research objectives for the technical team at the universal joint factory. To this end, they have finalized a meticulous plan: starting from the theoretical foundations of sealing, they combine typical sealing failure modes and actual operating conditions, leverage digital computational analysis platforms to examine various influencing factors, and conduct theoretical calculations and optimizations on aspects such as lip contact strength and service life, sealing fluid pressure, assembly reliability, heat transfer, and thermodynamics. They have identified different optimal combinations and then carried out prototype testing and comparative verification.

In the early stages of the project, after countless rounds of experiments, the experimental data failed to show any consistent patterns that matched the theoretical analysis—and in some cases, the results even contradicted each other. Despite repeated attempts at adjustment, they found themselves stuck with little progress. “We kept ‘pumping ourselves up’—everything depended on sheer grit and hard work! So we weren’t intimidated by the temporary difficulties. We went back again and again to carefully sort through and discuss the massive amounts of data. After months of intense effort, we finally uncovered a pattern hidden among several sets of overlooked details,” said Xixi, a member of the project team. During those few months, everyone often stayed up late into the night, engrossed in studying and analyzing experimental data, even missing meal times because of their relentless pursuit. As the saying goes, “Effort never betrays those who put their heart into it.” After repeated verification and practical testing, the new-generation “breathable” sealing structure achieved remarkably good experimental results and demonstrated stable performance in subsequent full-vehicle integration tests.

For the high-strength outer ring of bearings, the technical team has, for the first time, specifically proposed a sub-module verification method and an ultimate strength algorithm based on computational dynamics, integrating digital correlations across design, manufacturing processes, fit tolerances, and multiple operating conditions. From the entirely new design standards for lightweight, high-strength cross shafts, to the sealing and lubrication design standards for the core bearing components, and further to the high-strength calculation and testing standards for bushings, this series of standards—developed from scratch—has laid a solid foundation for continuous product innovation and breakthroughs.

In this project, everyone deeply realized that “how excellent a product is not only depends on how thoroughly the underlying research has been conducted, but also on how meticulously the standards have been formulated. When an industry lacks established standards, it’s even more crucial to start from first principles and develop standards that reflect the product’s superior performance, thereby leading the industry’s development.”

Unified Design and Manufacturing—Winning Quality at the Front Line

In recent years, thanks to China’s effective pandemic control measures, supply chains have remained relatively stable, prompting many world-class automakers to shift their key component projects to China. The main challenge in such projects lies in rapidly scaling up production while maintaining high-quality standards. Given that the universal joint factory was already operating at near-full capacity, ensuring on-time mass production and shipment of these project products has become the biggest hurdle.

No matter how high the technical and quality requirements are from our high-end customers, the universal joint factory always rises to the challenge. We have assembled core personnel from various specialties into project teams composed of experts in technology, quality, and process equipment, thereby establishing a comprehensively integrated production model covering design, manufacturing, and testing. This ensures that we meet our customers’ stringent demands for product quality and delivery schedules, allowing our high-strength, lightweight universal joints to fully demonstrate their superior performance in the market.
The project team worked day and night, closely monitoring the production line, developing multiple process options, and rigorously comparing and validating data from each option to identify the optimal machining solution. To overcome bottlenecks in production capacity, the team collaborated closely, independently developed specialized production equipment tailored to product design requirements, and successfully passed equipment acceptance testing, effectively addressing the issue of insufficient capacity. In terms of quality control, the team established a comprehensive set of operational procedures and inspection standards, ensuring that all manufactured products meet the customer’s stringent quality requirements. After mass production began, the team conducted daily inspections of the production site, promptly addressing any issues that arose. Additionally, the team held weekly conference calls with the customer to coordinate and resolve various matters during the mass-production phase, thereby guaranteeing that the products consistently met the required specifications. Furthermore, technical personnel regularly visited the customer’s after-sales service locations to track and evaluate the successful mass production of the project, fully satisfying the customer’s demands for both quantity and quality, and earning high praise from the customer. These concerted efforts have boosted the customer’s confidence in the company’s products, bringing greater economic benefits to the company.
Currently, our high-strength, lightweight heavy-duty truck universal joints can deliver superior performance parameters among products of the same specification size, enabling smaller-sized components to replace larger ones and achieve weight reduction. This has enhanced our product competitiveness, strengthened our product development and testing capabilities, expanded our production capacity, and allowed us to proactively meet market demands. “After successfully developing this product, we have begun mass-supplying it to leading domestic and international OEMs. Under the current trend in heavy-duty truck technology toward higher strength, lighter weight, and smaller sizes, the market prospects for our high-strength, lightweight heavy-duty truck universal joints are exceptionally promising—and we’re more motivated than ever,” said the project team with great confidence.