Bonfiglioli CAFS Reducer Selection and Application Guide

Bonfiglioli CAFS series gearbox selection and engineering application practice: a complete guide from parameter interpretation to fault prevention

In the field of industrial transmission, Bonfiglioli's CAFS series gearboxes are renowned for their modular design and high reliability. For on-site engineers and system integrators, accurately selecting, verifying, and installing equipment in the face of a large technical manual is the key to ensuring long-term stable operation of the equipment. This article will be based on the official technical documents of the Bangfeili CAFS series (covering C-series helical gears, A-series spiral bevel gears, F-series shaft mounted and S-series single-stage reducers), systematically sorting out the full process engineering practice guidance from core parameter calculation to special operating conditions (such as ATEX) application.

Core parameters and calculation logic before selection

The failure of gearbox selection often stems from confusion between the concepts of basic torque and power. In Bonfiglioli's system, engineers must prioritize defining the following three core torques:

Rated torque（Mn two M n2）This is the service coefficient of the gearbox

fs=one

f s=At 1 o'clock, the torque value that the output shaft can continuously transmit is the mechanical capability benchmark of the gearbox.

Required torque（Mr two M r2）The torque demand determined by the actual application load is the fundamental basis for selection.

Calculate torque（Mc two M c2）The core comparison value during selection is calculated using the following formula:

Mc two=Mr two×fs<Mn two(one)

M c2=M r2×f s<M n2(1)

This formula reveals the only criterion for successful selection: the calculated torque must be less than the rated torque of the corresponding speed ratio in the sample. Among them, f_s is the service coefficient, and its value is a key variable for selection.

Service coefficient（fs）The dynamic determination method

The service factor is not a fixed safety margin, but a dynamic variable determined by the daily running time, hourly startup frequency, and load characteristics (K-factor). According to the chart (A4) in the manual:

Load level (K1, K2, K3): K1 corresponds to a uniform load (such as a smoothly running conveyor belt), and K3 corresponds to a heavy impact load (such as a crusher or mixer). Engineers need to calculate the mass acceleration coefficient K based on the inertia ratio between the driving motor and the driven machinery, in order to determine the curve.

Starting frequency and duration: High starting frequency will significantly increase the fatigue loss of gears and bearings, which must be compensated by increasing the value of f_s.

Engineering Warning: In lifting applications involving personnel safety, regardless of the calculated values, it is necessary to contact the technical department of Bangfeili for special verification and not rely solely on this chart.

Thermal power（Pt）Verification: Preventing the Trap of "Cold Selection"

Meeting the mechanical strength requirements does not necessarily mean that the gearbox can work for a long time. Thermal power（Pt）Verification is the key to preventing premature aging and degradation of lubricating oil and bonding of gear tooth surfaces.

The manual clearly states that thermal power refers to the heat dissipation capacity under continuous operation at an ambient temperature of 20 ° C. When the operating conditions change, the actual available thermal power needs to be calculated according to the formula

Pt=Pt×ft Make adjustments. F_t is affected by environmental temperature and intermittency ratio.

Interval rate (I) calculation:

I=tftf+tr×

one hundred(two)

I= t f+t r t f ×100(2)

among which

tf To carry the working hours,

tr For downtime and rest periods.

Application points: For reducers with a speed ratio greater than 45 or more than 3 stages, due to their low efficiency, the heat generation is usually less than the heat dissipation, and thermal verification can often be exempted, but mechanical strength verification must be carried out.

4. Accurate verification of radial and axial loads

Radial force applied by external transmission components (such as pulleys, sprockets)（Rc one,Rc two R c1, R c2）It is the main cause of output shaft bending or premature bearing failure. When calculating the radial force generated by external transmission components, the coefficient should be selected according to the transmission typeKr Chain drive takes 1, gear drive takes 1.25, V-belt drive takes 1.5, and flat belt drive takes 2.0. The calculation formula is as follows:

Rc one/two=two thousand×M one/two×Krd(fifteen)

R c1/2= d2000×M 1/2×K r (15)

among which D is the pitch diameter of the transmission component.

Regarding the determination of the position of the load application point:

The manual specifies two verification methods:

Mid point loading: If the load point is at the midpoint of the shoulder extension length, directly compare the rated radial force in the sample

Rn Just enough.

Non midpoint loading: If the distance between the load application point and the shoulder of the axis is xx， It is necessary to convert the allowable radial force. Taking the output shaft as an example, the converted allowable radial force

Rx two=Rn two×ab+x R x2=R n2× b+xa

Among them, a and b are constants corresponding to different machine base numbers. only in

Rc two≤Rx two

R c2≤R x2

It is considered safe only under certain conditions.

In addition, axial thrust loads are usually checked at 20% of the coaxial radial force. If there is no radial force, the pure axial force that the bearing can withstand can reach 50% of the rated radial force.

Lubrication Strategy: Selection of PAO, PAG, and Mineral Oil

The classification of lubricating oil in the manual is of great practical guidance significance:

Life Lubricated: For small machine base sizes (such as C05-C41), synthetic oil has been added at the factory and does not require regular replacement.

Mineral Oil restriction: only applicable in service factor

fs≥one point three zero f s Mineral oil is allowed to be used when ≥ 1.30, as synthetic oil (PAO/PAG) can provide a more stable oil film and higher thermal oxidation stability under high loads.

The exclusivity of PAG (polyethylene glycol) oil: The manual clearly states that the A series (spiral bevel gear) A05-A60 machine base must use PAG oil (recommended viscosity 320) forcibly, because PAG oil has extremely high extreme pressure and anti-wear properties, which can effectively cope with the huge contact stress generated in spiral bevel gear transmission.

Special working condition application: derating treatment of ATEX explosion-proof configuration

When using A-series explosion-proof reducers in explosive environments, in addition to following the standard selection process, additional mechanical and thermal derating treatment is required, and explosion-proof dedicated Fluoro elastomers and breathing valves must be used.

Mechanical derating (ATEX specific service factor):

For the configuration of standard IEC interfaces, it is required that the service factor of the entire transmission chain must be≥one point four≥ 1.4.

For direct input configurations, it is necessary to multiply the rated torque by 1400 min ⁻¹fATEX=one point two fivef ATEX=1.25. For machine base numbers within a specific speed ratio range,

fATEX Need to be raised to 1.4.

ATEX thermal power calculation（Pt）：

The calculation formula is extended to:

Pt=PtB×fTa×fratio×fPOS×fINT×fAIR

Pt BP tB Basic thermal power (table value).

fTa Environmental temperature factor (1.0 at 40 ° C, reduced to 0.76 at 60 ° C).

fPOS Installation location factor (B3/B8 is 1, V-shaped installation is 0.8).

Installation and maintenance: Avoid "last mile" failure

Shaft end installation fit: When the output shaft of the reducer is cylindrical, the inner hole of the fitting should be machined to ISO H7 tolerance. Interference fit will damage the bearing clearance and cause bearing sintering.

Servo Adapter: When adapting a servo motor or using a clamping mechanism (SC code), it is necessary to ensure that the keyway on the motor shaft is aligned with the slot of the clamping device, and if the motor shaft has a key, the key must be removed. The torque for tightening the locking screw must strictly refer to the torque value given in the manual drawing.

Storage requirements: Long term storage (>6 months) must be equipped with SLM (mineral oil compatible) or SLP (polyethylene glycol oil compatible) anti-corrosion options. The equipment should be placed on a wooden support to avoid direct grounding, and the input shaft should be rotated regularly to prevent bearing adhesion.