Detailed explanation of the production process of electric transaxle

Detailed explanation of the production process of electric transaxle
As one of the core components of many equipment, the production process of electric drive axle (Electric transaxle) has attracted much attention. For international wholesale buyers, in-depth understanding of this complex and sophisticated production process can not only help them better evaluate the strength of suppliers, but also provide important basis for product customization and procurement. This article will comprehensively analyze the production process of electric drive axle, from design and development to finished product testing, every link will be explained in detail for you.

1. Design and development stage
(I) Demand analysis and conceptual design
At the beginning of the production of electric drive axle, the first thing to do is demand analysis and conceptual design. At this stage, engineers will work closely with customers or marketing departments to deeply understand the target market, application scenarios and customers’ specific requirements for product performance, size, weight, etc. For example, for electric cars used for urban commuting, their electric drive axles need to have the characteristics of high efficiency, light weight and low noise; while for electric commercial vehicles, they pay more attention to torque output, durability and load-bearing capacity.
Based on these needs, engineers began to carry out conceptual design. They will use advanced computer-aided design (CAD) software to draw a three-dimensional model of the electric drive axle and preliminarily determine the layout, shape and size of each component. In this process, it is also necessary to consider the compatibility and interface design with other vehicle systems to ensure that the electric drive axle can be perfectly integrated into the vehicle architecture.
(II) Detailed design and simulation analysis
After the conceptual design is completed, the detailed design and simulation analysis stage will be entered. Engineers will carry out detailed design of each component of the electric drive axle, including the module, number of teeth, tooth shape of the gear, the stator and rotor structure of the motor, the transmission ratio of the reducer and other key parameters. These designs need to be based on rigorous mechanical principles and electromagnetic theories, combined with rich practical experience.
In order to verify the feasibility and performance of the design, engineers will use computer simulation software to conduct multi-faceted analysis. For example, finite element analysis (FEA) is used to evaluate the stress distribution and deformation of key components such as gears and shafts under high-load conditions to ensure their strength and reliability; multi-body dynamics simulation is used to study the vibration and noise characteristics of the entire transmission system and optimize the system’s NVH (noise, vibration and harshness) performance; motor performance simulation is used to predict key indicators such as motor efficiency, torque output and temperature rise under different working conditions to provide a basis for subsequent optimization design.

2. Parts Processing and Manufacturing

(I) Motor Stator and Rotor Manufacturing

As the core power source of the electric drive axle, the manufacturing quality of its stator and rotor directly affects the performance of the entire system. Stator manufacturing usually adopts a lamination process to stack silicon steel sheets into a stator core according to design requirements, and then embed insulation materials and winding coils in the core slots. The production of windings requires high-precision winding equipment to ensure that the number of turns, pitch and distribution of the coils are uniform to achieve efficient operation of the motor.

Rotor manufacturing varies according to the type of motor. For common permanent magnet synchronous motors, the rotor needs to embed high-performance permanent magnets on the core and perform precise pole magnetization. This process requires strict control of the size, position and magnetic properties of the permanent magnets to ensure the torque output and efficiency of the motor. At the same time, the rotor also needs to be dynamically balanced to ensure stability at high-speed rotation and avoid vibration and noise problems caused by imbalance.
(II) Gear processing and heat treatment
Gears are key components for transmitting power and changing speed in electric drive axles, and their processing accuracy and performance requirements are extremely high. Gear processing usually includes two stages: rough machining and fine machining. In the rough machining stage, forging or precision casting is used to process the blank material into a gear blank close to the final shape. Then fine machining is performed, and the tooth shape is accurately cut by a CNC machine tool (CNC) to ensure that the gear’s tooth surface accuracy, pitch cumulative error and contact accuracy meet the design requirements.
In order to improve the surface hardness and wear resistance of the gear while maintaining the toughness of the core, the gear needs to undergo a professional heat treatment process. Common heat treatment methods include carburizing and quenching and nitriding. In the carburizing and quenching process, the gear is carburized in a high-temperature furnace to form a hardened layer with a high carbon concentration on the surface, and then quickly quenched and cooled to harden the surface while the core still maintains good toughness. The nitriding process is to allow nitrogen atoms to penetrate the surface of the gear at high temperature to form a hard and wear-resistant nitrided layer. The heat-treated gears also need to undergo precision grinding and honing processes to further improve the finish and precision of the tooth surface and ensure the stability and low noise of the gear during operation.
(III) Manufacturing of reducer housing and differential
As the supporting structure of the electric drive axle, the reducer housing needs to have sufficient strength and rigidity, while also considering lightweight design. The housing is usually made of aluminum alloy or high-strength steel and is formed by casting, forging or precision stamping. During the housing processing process, its size and form and position tolerances need to be precisely controlled to ensure the assembly accuracy with internal components.
The differential is a key component in the electric drive axle to achieve differential rotation of the left and right wheels, and its manufacturing process is also precise and complex. The gear set of the differential includes planetary gears, half-axle gears and differential case. These parts have extremely high machining accuracy requirements and need to be processed by high-precision machine tools, and undergo strict testing and assembly. During the assembly process, the differential also needs to be lubricated and sealed to ensure its reliability and long-term effectiveness during operation.

3. Assembly and debugging
(I) Pre-assembly and testing of parts
During the assembly stage of the electric drive axle, the parts must be pre-assembled and tested first. The main components such as the motor, reducer, and differential are preliminarily assembled according to the design drawings and process requirements, and the matching between the components is checked to see if there is any interference or looseness. In this process, key components also need to be tested for performance, such as the no-load current and speed of the motor, the transmission efficiency and noise level of the reducer, etc., to ensure that each component meets the quality standards before entering the final assembly.
(II) Assembly assembly and torque calibration
After pre-assembly and testing, the assembly of the electric drive axle begins. The assemblers follow the strict process flow to accurately install each component to the designated position, and use a professional torque wrench to calibrate the torque of the connecting bolts. Torque calibration is a key link to ensure assembly quality. Different bolt connection parts have strictly specified torque values. Excessive torque may cause damage to the bolts or connectors, while too little torque may cause the connection to loosen, affecting the reliability and safety of the product.
During the assembly process, the lubrication system and sealing system of the electric drive axle also need to be carefully inspected and debugged. Ensure that the filling amount and distribution of lubricating grease are reasonable to avoid component wear caused by poor lubrication; at the same time, check the sealing performance of each sealing part to prevent problems such as oil leakage or water ingress, and ensure the normal operation of the electric drive axle under various working conditions.
(III) Vehicle matching and performance debugging
After the electric drive axle is assembled, it needs to be matched with the whole vehicle and performance debugged. At this stage, engineers install the electric drive axle on the prototype vehicle and conduct a series of vehicle performance tests and debugging. Including power output characteristic test, check the torque output and power matching of the electric drive axle under different vehicle speeds and load conditions; perform power performance tests under acceleration, deceleration and climbing conditions, optimize the control strategy of the motor and the transmission ratio of the reducer; at the same time, evaluate and debug the NVH performance of the whole vehicle, and reduce the vibration and noise of the transmission system and improve driving comfort by adjusting the meshing clearance of the gears and optimizing the electromagnetic compatibility of the motor.

4. Quality inspection and finished product packaging
(I) Appearance and size inspection
In the quality inspection link, the appearance and size of the electric drive axle must be strictly inspected first. Check whether there are scratches, bumps, rust and other appearance defects on the surface of the product to ensure that the appearance quality of the product meets customer requirements. At the same time, use high-precision measuring instruments to measure the key dimensions of the product, including the dimensional accuracy of the installation interface, wheelbase, gear module and number of teeth, etc., to ensure that it is within the allowable tolerance range and meets the assembly requirements with the whole vehicle and other components.
(II) Performance and function test
Next, the performance and function test of the electric drive axle is carried out. On a professional test bench, various actual working conditions are simulated to conduct a comprehensive test on the product’s power output, torque response, transmission efficiency, maximum speed and other performance indicators. At the same time, check whether the differential function of the differential is normal, and whether the motor’s start, stop and reverse functions meet the design requirements. During the test, it is also necessary to monitor the noise and vibration levels of the product to ensure its stability and low noise characteristics during operation.
(III) Finished product packaging and protection
After passing strict quality inspection, the electric drive axle enters the finished product packaging stage. According to customer requirements and product transportation conditions, professional packaging materials and packaging methods are used to package the product. The packaging should not only ensure that the product is not damaged during transportation, but also be easy to load and unload and store. Usually, wooden packaging boxes or plastic pallets are used for packaging, and protective materials such as shockproof foam and moisture-proof paper are filled in the box to focus on protecting the key parts of the product. At the same time, the product model, specifications, quantity, production date and other information, as well as necessary warning signs such as “fragile”, “moisture-proof”, “upward”, etc. are marked on the packaging box to ensure the safety of the product during transportation and storage.

5. Summary and Outlook
The production process of electric drive axles is a complex and precise process, involving close cooperation of multiple links and strict quality control. From design and development to parts processing, to assembly and debugging and quality inspection, each step requires engineers to have deep professional knowledge and rich practical experience. With the continuous development of the new energy vehicle market and the continuous advancement of technological innovation, the production process of electric drive axles will also be continuously optimized and upgraded.