Although soft-tooth surface and hard-tooth surface reducers are highly similar in appearance and structure, due to differences in material properties, heat treatment processes, and applicable working conditions, there are significant differences in installation specifications between the two. Generally speaking, hard-tooth surface reducers have extremely strict requirements for assembly accuracy, especially in terms of shaft alignment, basic levelness, and lubrication control. The error tolerance rate is extremely low; while the installation conditions of soft-tooth surface reducers are relatively tolerant, but basic assembly guidelines still need to be followed to ensure smooth operation of the equipment.
1. Preparation before installation: Check the center of gravity and tool requirements
The gears of the hard-tooth surface reducer have been carburized and quenched, and the tooth surface hardness is usually greater than 350HB. Although it has strong wear resistance, it is relatively brittle. If it is subjected to improper external force during transportation or installation, it is easy to produce micro-cracks or tooth chipping. Therefore, before installation, the gear meshing surface must be carefully checked for collision damage and the anti-rust oil film must be completely removed. At the same time, parameters such as model, transmission ratio, and center distance need to be strictly checked to ensure that they are completely consistent with the design. In terms of tool preparation, it is recommended to use a laser alignment instrument with an accuracy of ±0.001mm/m to replace ordinary feeler gauges for high-precision shaft system alignment.
In contrast, the tooth surface hardness of the soft tooth surface reducer is low (≤350HBS), and the material is mostly 45 steel or 40Cr. After quenching and tempering treatment, it has excellent toughness and strong impact resistance. The preparatory work before installation mainly focuses on the cleanliness of parts and the inspection of matching dimensional tolerances to ensure that there are no rust stains, burrs and other impurities that affect the assembly. In terms of measuring tools, alignment and adjustment work can be completed using conventional measuring tools such as dial indicators and feeler gauges.
2. Shaft system alignment: significant differentiation in accuracy standards
Shaft system alignment is a key link that determines the life of the reducer, and hard-tooth surface reducers have extremely strict requirements on this. The coaxiality error between the input shaft and the motor shaft must be controlled within ≤0.05mm, and the end face parallelism deviation must be ≤0.03mm. In order to avoid running eccentricity due to thermal expansion or vibration, a laser alignment instrument must be used for dynamic calibration, and the coupling bolts must be tightened symmetrically and evenly to prevent distortion of the flange surface.
The alignment standards of soft-tooth surface reducers are relatively loose. The allowable error of coaxiality is generally between 0.1~0.2mm. Use a dial indicator to measure and adjust to meet the requirements. In addition, soft tooth surface reducers have lower installation requirements for elastic couplings and can better adapt to axial and angular deviations within a certain range.
3. Gear and bearing assembly: process flow and operating specifications
In the assembly of core components, the gears of hard-tooth surface reducers are mostly processed by gear grinding, and the accuracy reaches ISO level 6 or higher. Forcible knocking is strictly prohibited during assembly to avoid damaging the high-precision tooth surfaces. The bearings usually use precision rolling bearings, which need to be heated and the heating temperature is strictly controlled at 80~100°C to prevent deformation of the inner ring. After assembly is completed, the input shaft must be turned manually to check whether it is flexible and free of jamming. Any slight assembly stress may seriously affect the meshing state of the gear.
The gears of soft-tooth surface reducers are mostly hobbing or shaping and then quenched and tempered. The accuracy requirements are relatively low, and slight modifications are allowed during assembly. The bearing assembly also often adopts the thermal installation method, and the heating temperature is also controlled at 80~100°C. Different from the hard tooth surface, after the soft tooth surface reducer is assembled, the contact spots and backlash of the gear can be detected through preliminary trial operation to further verify the assembly quality.
