With the development of intelligent and drive-by-wire automotive technology, the response speed and control accuracy of traditional hydraulic brake systems can no longer meet the requirements of L3+ autonomous driving. As a new generation of brake-by-wire technology, EMB (Electromechanical Brake System) completely abandons traditional hydraulic components and directly controls braking via electrical signals, making it a major development direction for automotive braking systems. Xunwei Precision’s 500 million yuan EMB project launched in 2025 is a strategic layout in cutting-edge core automotive components, supported by its profound technological accumulation in ball screws.

Core Principle & System Architecture

The EMB system is a fully electrically controlled brake-by-wire system. Its core structure consists of an Electronic Control Unit (ECU), electric motor, mechanical transmission mechanism, and brake caliper—with the ball screw as the key component of the transmission. After receiving the braking signal, the ECU controls the motor to convert electrical energy into mechanical energy. The ball screw then accurately transforms the motor’s rotational motion into linear motion, pushing the brake piston and precisely controlling its displacement to achieve accurate braking force adjustment. Meanwhile, the EMB system is equipped with an independent motor for each wheel, enabling “four-wheel independent electric braking” and precise single-wheel braking force distribution based on vehicle driving conditions.

Core Advantages of EMB System

Compared with traditional hydraulic brake systems, the EMB system offers outstanding performance benefits thanks to full-electric control and high-precision ball screw transmission, which is why it has become the upgrade direction for automotive braking:

1. Fast response, safer braking: The response time of traditional hydraulic braking is about 300ms, while EMB reduces it to 80–100ms—over 3 times faster. At 100km/h, emergency braking distance is shortened by 9 meters. The AEB system equipped with EMB can completely avoid collisions at 60km/h, greatly improving driving safety.
2. High control precision, suitable for intelligence: EMB achieves braking force control accuracy of 0.1MPa, 5 times higher than hydraulic systems, with ±3% precision for single-wheel braking force. With a fully decoupled design, it integrates seamlessly with autonomous driving systems and supports braking requirements for L3+ autonomous driving.
3. Lightweight and eco-friendly: By removing hydraulic lines and pumps, EMB reduces weight by 20–35% (about 10–15kg), improving vehicle efficiency and extending EV range by 5–17%. It also eliminates brake fluid, removing environmental and safety risks from leakage. A simplified structure cuts parts by 30%, lowering long-term operating costs.

4. Strong integration, simpler system: EMB can integrate EPB (Electronic Parking Brake) function, simplifying overall brake system design, reducing component count and assembly difficulty, while improving system reliability.

Xunwei Precision’s EMB Project Layout

With a total investment of 500 million yuan, Xunwei Precision’s EMB project includes a new 100-mu production base and 69,000-square-meter factory in Guangde Economic and Technological Development Zone, Anhui. Leveraging its core ball screw technologies, the company will realize R&D and mass production of EMB systems, with an expected annual output value of 1 billion yuan. As a leading enterprise in automotive ball screws, Xunwei Precision has mastered the core technologies of precision transmission for vehicles. Its expertise in high-precision machining, precise control, and strict quality management accumulated in ball screw R&D and production will provide key technical support for EMB development and manufacturing, realizing an upgrade from core components to system-level products.