A ball screw is a high-precision transmission component that converts rotary motion into linear motion and vice versa. By replacing sliding friction with rolling friction, it features high precision, high transmission efficiency, reversibility, and long service life. It has become a key component in core automotive systems such as braking, steering, parking, and transmission shifting, and serves as the foundation for precise control and efficient transmission in vehicles.

Automotive ball screws mainly consist of a screw shaft, nut, steel balls, preloader, return tube, and dust seal. The core principle is that steel balls circulate and roll in the spiral grooves between the screw and nut, converting traditional sliding friction into rolling friction and greatly reducing transmission loss. When the screw rotates, the steel balls push the nut to move linearly along the screw axis, achieving accurate conversion from rotational torque to axial force. The structure is also reversible and can convert linear motion back to rotary motion to meet the transmission needs of different automotive systems. In automotive steering systems, the motor drives the ball screw to rotate, and the nut converts torque into linear thrust on the rack for precise wheel steering. In braking systems, the ball screw converts motor power into clamping force of the brake caliper to achieve accurate braking force transmission.

Complex vehicle operating conditions impose strict requirements on the precision, wear resistance, reliability, and stability of ball screws. According to standards for automotive brake ball screw assemblies, for ball screws with a nominal diameter of 6mm to 50mm: axial backlash shall not exceed 50μm; transmission efficiency shall be at least 85%; raceway surface hardness shall reach 58 HRC to 64 HRC; and after fatigue life testing, the ratio of rated life test value to basic rated life shall be ≥1.4. Meanwhile, automotive ball screws must adapt to complex environments including high and low temperatures, vibration, and impact. Cleanliness and residual magnetism are strictly controlled: particle weight per assembly shall not exceed 2.0mg, and maximum residual magnetism shall not exceed 0.5mT, ensuring stable operation in core automotive systems.

Xunwei Precision has focused on R&D of automotive ball screws and components since 2014, making it one of the earliest domestic enterprises to achieve mass production of ball screws for steering systems. Its products are widely used in core automotive applications including braking, parking, steering, and transmission shifting. The company has an annual production capacity of 8 million sets of ball screw assemblies, with production lines of leading scale and automation level in China. Its independently developed fully automatic assembly line for automotive ball screws enables high-precision, standardized mass production.

In terms of quality control and inspection, the company has obtained ISO9001, IATF16949 and other quality management system certifications. It is equipped with a full range of dedicated testing equipment for ball screws and a large number of German Zeiss coordinate measuring machines among the top in the province, allowing accurate measurement of dimensional tolerance, axial backlash, transmission efficiency and other key indicators to meet high automotive industry standards. With advanced manufacturing technology, sophisticated production processes, and strict quality control, Xunwei Precision’s automotive ball screws have been selected by many internationally renowned automakers, demonstrating the technical strength of domestic enterprises in the field of automotive ball screws.