Boxin · Hengzhen · Botrust
Precision Manufacturing・Powering the World
Core gear assembly of an integrated electric vehicle transmission
This is a core gear assembly for an integrated electric‑vehicle transmission, precision‑manufactured from high‑strength alloy materials such as carburized steels like 20CrMnTi. It encompasses various configurations, including helical gears, shaft-mounted gears, flanged ring gears, and splined shafts, and is specifically designed for new‑energy vehicle transmissions. Featuring high load capacity, low noise, high efficiency, and exceptional reliability, it serves as a critical component for reducing speed and increasing torque from the motor while ensuring efficient power transmission.
- Product Description
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1. Overall Positioning and Application Scenarios
- Target Audience : Integrated electric vehicle transmission (single-speed/multi-speed e‑drive axle gearbox), widely used in the electric drive systems of pure‑electric passenger cars and commercial vehicles.
- Component Role As a core transmission component, it performs the functions of power transmission, speed reduction and torque multiplication, torque distribution, and output, directly influencing the electric drive system’s transmission efficiency, noise levels, load-carrying capacity, and overall vehicle dynamic performance.
- Design Advantages Integrated, lightweight design that accommodates the demanding operating conditions of new‑energy vehicles—high‑speed motors, high torque output, and frequent start‑stop cycles—while meeting performance requirements for low backlash, high efficiency, and reduced NVH.
2. Material and Process Characteristics
- Material Selection : with 20CrMnTi Low-carbon alloy carburizing steels are predominantly used, with higher-grade alloy materials employed for certain heavy-duty components.
- Heat treatment process: carburizing and quenching followed by low-temperature tempering; the hardness of critical gear surfaces and journal necks can reach HRC58-63 The core maintains high toughness while exhibiting excellent wear resistance, contact fatigue strength, and impact resistance, making it well-suited to meet the demanding operating conditions of new‑energy vehicles—high rotational speeds and cyclic loading.
- Manufacturing process: Tooth profiles are produced using high-precision hobbing or shaping combined with gear grinding, achieving gear accuracy of 6–7 grades. The journal and spline sections undergo precision grinding, with tight tolerances for coaxiality and runout; coupled with dynamic balancing correction, this ensures smooth transmission, low noise, and high efficiency.
3. Analysis of the Structure and Functions of Each Component
Component Type Structural features Core Features Helical gear / Gear ring
Disc-shaped helical gear design: the outer ring features involute helical teeth, while the inner ring is equipped with a splined bore or flange mounting holes. As a driven or driving gear, it meshes with the shaft gear to achieve speed reduction and torque multiplication; the flange ring gear can be directly connected to the differential housing, transmitting torque to the wheels. Shaft gear (gear shaft)
The shaft body features an integrated design with a helical gear, with one end equipped with a journal/spline and the middle section incorporating the gear segment. As the driving gear shaft, it is directly connected to the motor’s output shaft, driving the driven gear to transmit power; the splined section ensures reliable torque transmission. Integrated gear shaft assembly
The shaft assembly integrates multi-stage helical gears, a journal, and a flange structure. Achieving multi‑stage transmission and power splitting, it serves as a core component of the transmission’s countershaft and intermediate shaft. Its integrated design reduces assembly steps and enhances transmission stiffness. Spline output shaft
Step shaft design, with splines and journal bearings at both ends and a support section in the middle. As the transmission output shaft, it transmits the reduced‑speed power to the differential/drive axle, supports the bearings, and withstands radial loads and torque. 4. Performance and Application Value
- Core Advantages ：
- High load capacity, high efficiency : The multi-tooth contact characteristics of helical gear engagement, combined with precision gear‑tooth machining, enable a transmission efficiency of 98% or higher while also accommodating high torque output.
- Low noise, low NVH High-precision helical gear design ensures smooth meshing; combined with a gear‑honing process, it reduces tooth surface roughness, effectively minimizing transmission noise and vibration and enhancing overall vehicle ride comfort.
- High reliability and long lifespan Carburizing and quenching enhance the tooth surface’s wear resistance and fatigue strength, making it well-suited to the high‑frequency start‑stop cycles and alternating loads typical of new‑energy vehicles, thereby extending the transmission’s service life.
- Compatible Scenarios : Integrated electric drive axle transmissions for various types of battery-electric and hybrid vehicles, adaptable to electric drive systems with different gear ratios and torque ratings, are critical core components ensuring the stable operation of new‑energy vehicle powertrain systems.
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