Custom Helical Bevel Worm Geared Motor Manufacturers

How to ensure the accuracy of the shaft alignment of the helical gearbox?

1. Technical connotation and influencing mechanism of shaft alignment accuracy
(I) Theoretical basis of geometric accuracy
The essence of shaft alignment is to ensure that the coaxiality, parallelism and verticality of the input shaft and output shaft of the reducer in space meet the design standards. Taking the parallel shaft helical gear reducer as an example, if the parallelism error of the two shafts exceeds 0.05mm/m, it will lead to uneven load distribution when the gears are meshing, resulting in eccentric load, which will lead to increased vibration, increased noise and abnormal tooth surface wear. According to the data in the mechanical design manual, for every 0.01mm increase in coaxiality error, the transmission efficiency will decrease by about 0.3%, and it is easy to induce shaft bending fatigue failure.
(II) Dynamic requirements of mechanical balance
During the transmission process, the shaft system is subjected to the combined effects of torque, bending moment and centrifugal force. When there is a centering deviation in the shaft system, additional dynamic loads will be generated, forming a periodic exciting force. Taking a certain type of reducer as an example, when the input shaft speed is 1500r/min, if there is a radial runout of 0.1mm, a centrifugal force of about 120N will be generated, which may cause resonance risk. Dynamic simulation shows that accurate alignment can reduce the vibration intensity of the shaft system by 60%-80%, significantly improving the stability of the transmission system.
(III) Compensation mechanism for thermal deformation
When the reducer is running, the heat generated by gear meshing and bearing friction will cause thermal expansion of the shaft system. The difference in linear expansion coefficient between the aluminum alloy housing and the steel shaft (aluminum: 23×10⁻⁶/℃; steel: 11×10⁻⁶/℃) may cause the cold state alignment accuracy to shift in the hot state. Through thermal-structural coupling analysis, optimizing the bearing clearance configuration (such as using preloaded angular contact ball bearings) and the housing heat dissipation rib design, the alignment error caused by thermal deformation can be controlled within 0.02mm.
2. Full-process process control of shaft alignment accuracy
(I) Traceability of component processing accuracy
Precision machining of shaft parts
Use CNC grinders (such as German Schleifring grinders) to grind the journal, and the dimensional tolerance is controlled at IT5 level, and the surface roughness Ra≤0.8μm. For stepped shafts, the coaxiality of each shaft segment is guaranteed to be ≤0.005mm through center hole positioning, and the online measurement system (such as Renishaw probe) is used to correct the machining parameters in real time.
Benchmark control of box manufacturing
As the benchmark for shaft assembly, the position accuracy of the bearing hole of the box is crucial. The CNC machining factory of Hangzhou Hengbai Reducer Co., Ltd uses horizontal machining centers (such as Japanese MAZAK machine tools) for box machining, and uses one side and two pins for positioning to ensure that the center distance tolerance of the bearing hole is ±0.015mm, the parallelism of the hole system is ≤0.01mm/100mm, and the verticality is ≤0.02mm/100mm.
(II) Refined design of assembly process
Pre-assembly inspection system
Before assembly, use a three-coordinate measuring machine (such as the German Zeiss CMM) to conduct full-size inspection of shafts, gears, bearings and housings, and establish a component accuracy database. Through statistical process control (SPC) analysis, the component grouping and matching is realized, so that the matching clearance between the bearing and the journal and the housing hole is controlled within the range of 0.003-0.008mm.
Dynamic centering adjustment technology
A laser centering instrument (such as the Swedish Fixturlaser) is used for shaft system assembly and debugging, and the gasket thickness and bearing position adjustment amount are calculated through software simulation. For multi-stage gear transmission systems, follow the principle of "calibration from near to far, step by step", first adjust the high-speed shaft system, and then calibrate the low-speed stage in turn, to ensure that the cumulative centering error of each shaft system is ≤0.03mm.
(III) Deformation control of heat treatment process
Axis parts adopt vacuum quenching process (heating temperature 860℃, holding time 60min), and low-temperature tempering (180℃×2h) after oil cooling, so that the surface hardness reaches HRC58-62, the core hardness HRC30-35, and the heat treatment deformation is reduced (ovality ≤0.01mm). The aging treatment of the housing adopts vibration aging technology, and 50-300Hz variable frequency vibration is applied by the exciter to eliminate more than 90% of the casting stress and ensure the dimensional stability of the housing.
3. Advanced detection technology and quality assurance system
(I) Integration of multi-dimensional detection means
Static accuracy detection
Use high-precision cylindricity meter (such as Tokyo Precision of Japan) to detect the cylindricity of the shaft neck ≤0.003mm, and the gear runout inspection instrument to measure the gear radial runout ≤0.012mm, and the tooth direction error ≤0.008mm. The housing bearing hole is detected by pneumatic measuring instrument, and the hole diameter tolerance is controlled at ±0.005mm.
Dynamic performance test
The testing laboratory of Hangzhou Hengbai Reducer Co., Ltd is equipped with a comprehensive performance test bench, which can simulate the rated load (accuracy ±1%) and speed (resolution 0.1r/min) working conditions, and monitor the shaft vibration (≤1.5mm/s) and noise (≤75dB) in real time through the acceleration sensor (sensitivity 100mV/g) and the noise tester (accuracy ±0.5dB). The spectrum characteristics are analyzed through the data acquisition system (sampling frequency 10kHz) to identify abnormal frequency components caused by poor alignment (such as the increase in the amplitude of the 2nd frequency).
(II) Implementation of the quality management system
The company has passed the ISO 9001 quality management system certification and established a full-process traceability system from raw material procurement (such as the use of Baosteel 42CrMo steel, chemical composition deviation ≤0.02%) to finished product delivery. In the shaft alignment control link, three quality control points (parts processing, assembly debugging, performance testing) are set, and the PDCA cycle (plan-execute-check-process) is used to continuously optimize the process parameters. For example, by statistically analyzing the data in 2024, the first-time qualified rate of shaft alignment has increased from 92% to 98.5%, and the customer feedback failure rate has decreased by 70%.
4. Industry practice and technological innovation trend
(I) Analysis of typical application scenarios
In the rolling mill transmission system of the metallurgical industry, the shaft alignment accuracy of the helical gear motors directly affects the uniformity of the rolling thickness of the steel plate. A steel company uses the HB-RV series reducer of Hangzhou Hengbai Reducer Co., Ltd. Through the above process control, the shaft alignment error is controlled within 0.02mm, the vibration intensity of the rolling mill is reduced from 8.5mm/s to 3.2mm/s, and the rolling scrap rate is reduced by 40%.
(II) Integrated application of intelligent technology
At present, the shaft alignment accuracy control is developing in the direction of intelligence. For example, by introducing machine vision technology (such as an industrial camera with a resolution of 2000×2000 pixels), the image processing algorithm can automatically identify the shaft end reference features and realize non-contact measurement of centering errors, which improves efficiency by more than 5 times. At the same time, by building a virtual simulation model for shaft alignment based on digital twin technology, the accuracy changes under different working conditions can be predicted in advance, and the process parameter configuration can be optimized.