How to ensure installation accuracy when a shaft-mounted non-standard reducer is running at high speed

Publish Time: 2025-09-29 Origin: Site

Because the shaft-mounted non-standard reducer is not supported by the base, it completely relies on the direct connection between the output shaft and the load shaft (or motor shaft) to achieve positioning. At high-speed operation (usually ≥3000rpm), slight shaft system deviation will be amplified into vibration and impact, which will directly affect the equipment life and operation stability. To ensure installation accuracy, the four core dimensions of axis system centering, connection rigidity, reference constraints, and error compensation must be implemented, and the entire process is precisely controlled. The specific methods are as follows:

1. Core premise: Accurately control the coaxiality of the shaft system (high-speed precision'lifeline')

The accuracy of shaft-mounted installation is essentially the neutrality of 'axis-axis'. The radial offset at high speed must be ≤0.01mm and the angular offset ≤0.03°, which must be achieved through professional tools and processes:

1. Use the 'benchmark priority' principle to determine the positioning benchmark

The load shaft (such as the working machine spindle and motor shaft) are preferred as the reference shaft, and the reducer output shaft is actively adapted and aligned rather than the reverse adjustment of the reference shaft (the load shaft is usually fixed by the bearing seat and has higher position accuracy).
If the reducer needs to connect the motor and the load at the same time ('intermediate shaft'), the load shaft must be used as the first reference , first align the reducer and the load shaft, and then adjust the centering of the motor shaft and the reducer input shaft (avoid the accumulation of double deviations).

2. Replace 'visual calibration' with professional centering tools

Must be used in high-speed scenarios

Laser centering instrument

(Accuracy can reach 0.001mm), not a dial meter or ruler (Error ≥0.05mm), specific operation process:

Fix the laser emitter and reflector at the 'near connection end' of the reducer output shaft and load shaft respectively (distance to the connection surface ≤50mm, reducing the measurement error of the long arm);
Manually rotate the two axes for one round (360°), and record the radial deviation (ΔY) and the angular deviation (Δα);
Adjust the position through the reducer's 'fine-adjustment foot' (pre-installed, such as M12 adjustment bolt + oblique shim) until the deviation meets: when the speed is 3000-5000rpm, ΔY≤0.02mm, Δα≤0.05°; when the speed is >5000rpm, ΔY≤0.01mm, Δα≤0.03°.

2. Key means: Choose a rigid connection method for high-speed adaptation

The accuracy and rigidity of the connecting parts directly determine the stability of the shaft system. The traditional 'key connection + ordinary coupling' extensive mode needs to be abandoned and the following high-speed adaptation scheme is adopted:

1. Priority is given to the use of 'bonded rigid connections' to reduce the weakening of the shaft system

Expansion sleeve connection : The core is selected as a multi-flap hydraulic expansion sleeve (rather than a mechanical expansion sleeve), which achieves the interference coordination between the shaft and the hub through hydraulic oil pressurization. The centering accuracy is ≤0.01mm, and there is no keyway to weaken the shaft strength (the keyway will cause stress concentration in the high-speed shaft and easily cause fracture). During installation, the finish of the expansion sleeve and the shaft and the hub should be ensured that the fitting surface of Ra≤1.6μm (avoid impurities affecting the centering), and the hydraulic pressure should be controlled according to the manual (usually 150-200MPa).
Cone sleeve connection : If the load end is a hub with a conical hole (such as gears, synchronous pulleys), a precision cone sleeve + lock nut is connected. The cone surface matching accuracy must reach IT5 level. After locking, use a dial meter to detect the jumping of the hub end surface ≤0.015mm.

2. The coupling must be selected as 'low compensation, high rigidity' type

If there is a slight deviation of the shaft system (which cannot be completely eliminated), it is necessary to compensate through the coupling. However, it is strictly forbidden to use elastic couplings at high speeds. You must choose:

Metal diaphragm coupling : preferentially single diaphragm or double diaphragm structure (stainless steel material, thickness 0.2-0.5mm), its compensation amount is small (radial compensation ≤0.1mm), low moment of inertia, and no elastomer aging problem (avoid elastomer breakage at high speed). During installation, the perpendicularity between the diaphragm and the shaft must be ensured ≤0.01mm.
TabooSelection : It is absolutely forbidden to use plum couplings, nylon couplings, and universal joint couplings - the elastic body is prone to fatigue at high speeds, and the imbalance of the universal joint will cause vibration amplification of more than 10 times.