Bonfiglioli Precision Planetary Gearbox Selection and Application Guide

Bonfiglioli Precision Planetary Gearbox Selection and Application Guide

Introduction: The Value of Precision Planetary Gearboxes in Industrial Transmission

In the field of industrial automation and robotics, the accuracy, rigidity, and dynamic response of the transmission system directly affect the overall performance of the machine. Bonfiglioli, with nearly 20 years of experience in motion control, has developed a full range of precision planetary gearboxes covering high dynamic servo to economical positioning. Its product line is divided into two major camps: Performance Line - targeting high-end applications with high torque density, extremely low backlash, and high stiffness requirements; Effective Line - meets medium precision requirements with high cost-effectiveness, flexible installation, and good compatibility. Whether it is packaging, material handling, automatic warehousing, or machine tool feeding, correct selection and configuration are the key to unleashing the potential of equipment. This article is based on the official technical manual of Bangfeili, systematically sorting out the characteristics of each series, selection calculation process, and engineering precautions, to help engineers quickly match the optimal solution.

Overview of Product Series Panorama

2.1 Performance Line

This line is designed specifically for high dynamic, high-precision servo applications and includes the following series:

TQ series: direct connection type, output torque up to 1600Nm, backlash ≤ 3arcmin (single-stage), leading torque density, IP65 protection, optional reinforced bearings.

TQK series: Right angle type (bevel gear planetary), saving installation space, back clearance ≤ 4arcmin (two-stage), suitable for compact layout.

TQF series: with output flange, standardized interface, easy to install quickly, high tilt torque bearing capacity.

TR series: Modular design, providing multiple versions such as coaxial, right angle input, and right angle output, multi-stage transmission, wide speed ratio range (3~729), and bearing life of 20000 hours.

MP series: Similar to TR but with slightly larger backlash (standard ≤ 15 arcmin), better cost-effectiveness, suitable for medium precision requirements.

2.2 Effective Line

For cost sensitive applications with moderate precision requirements:

TQFE/TQFEK: Direct connection and right angle type, compact flange structure, IP54， Back clearance ≤ 10arcmin (single-stage), economical type.

SL series: specially optimized for synchronous belt transmission, with output end designed with adaptive pulleys, high radial load capacity, and ultra compact.

LC/LCK: Direct connection and right angle type, outstanding cost-effectiveness, standard backlash ≤ 12arcmin, P option can increase torque.

MPE/MPEK: Medium precision positioning, high flexibility, multiple shaft end configurations.

KR series: bevel gear spiral gear, compact size, backlash ≤ 8arcmin, optional hollow shaft/solid shaft, IP65， Support S1/S5 working system.

Selection of core calculation steps

The correct selection should be based on the torque, speed, load, and lifespan requirements of the actual working conditions. The following is the key calculation process (refer to pages 14-20 of the manual):

3.1 Determine the transmission ratio and output speed

From the required output speed n ₂ and the rated motor speed n ₁:

i=nonentwo

i= n two n one 

If the operating condition includes multiple speed ranges, the equivalent output speed n ₂ _SQ needs to be calculated:

n two EQ=ntwo(one)tone+ntwo(two)ttwo+⋯+ntwo(n)tntone+ttwo+⋯+tn

n 2EQ= t one+t two+⋯+t n n 2(1)t one+n 2(2)t two+⋯+n 2(n)t n 

3.2 Calculate equivalent output torque (considering variable load)

For multi-stage load torques M ₂ (1)... M ₂ (n), their equivalent values are weighted by the cube root:

M two EQ=Mtwo(one)three n two(one)tone+M two(two)three n two(two)t two+…n two(one)tone+n two(two)t two+… three

M 2EQ= three  n 2(1)t one+n 2(2)t two+…M 2(1)three n 2(1)t one+M 2(2) three n 2(2)t two+…  

This formula is applicable to cyclic working conditions with variable speed and variable torque (such as frequent start stop).

3.3 Speed coefficient fn

The speed coefficient reflects the influence of input speed on the load-bearing capacity. Definition

Kn=one thousand

iK n= ione thousand(Experience value), if n two EQ⋅i≥Knn 2EQ⋅i≥K n

If fn=1, otherwise the graph will show fn (less than 1, derating is required).

3.4 Temperature coefficient fT

When the ambient temperature is above 30 ° C, the rating needs to be reduced. The manual provides a correction curve for 30-60 ° C, usually fT ≈ 0.9 at 40 ° C and ≈ 0.8 at 50 ° C.

3.5 Cycle frequency coefficient fz

For frequent start stop or forward/reverse rotation (S5 working system), fz should be calculated based on the number of cycles per hour Z (please contact the manufacturer if Z>6000). When ultimately selecting a gearbox, its rated torque Mn2 must meet the following requirements:

Mn two≥M two EQ×fn×fT×fzM n2≥M 2EQ×f n×f T×f z 

At the same time, the peak torque M ₂ _max shall not exceed the maximum acceleration torque Ma2 or emergency stop torque Mp2 in the manual (1000 times allowed).

3.6 Bearing life verification

The output bearing is subjected to radial force R ₂, axial force A ₂, and overturning moment MT ₂. It is necessary to calculate the equivalent radial force R ₂ _ EQ and axial force A ₂ _ EQ, and then estimate the basic rated life L ₁₀ₕ based on the bearing constant CB and life index p (usually 3.33) provided in the manual using the following formula:

L ten h=sixteen thousand six hundred and sixty-six n two EQ×(CBM two EQ)

pL 10h= n 2EQ sixteen thousand six hundred and sixty-six×( M 2EQ C B ) p

The specific formula manual has been simplified, and it is recommended to use the Bangfeili digital tool SERVOSft or Mosaic 3.0 for actual selection.

Key parameters and application scenarios of each series

4.1 TQ series (top-level performance)

Torque range: 50~1600Nm (different machine bases 060~160)

Back clearance: standard ≤ 3~4arcmin, decrease ≤ 2arcmin

Stiffness: extremely high (Ct value can reach up to 3325Nm/arcmin)

Features: IP65, fluororubber oil seal, low noise (60-70dB), suitable for machine tool spindles, robot joints, and high-precision positioning platforms.

4.2 TQK series (right angle performance)

Speed ratio: two-stage and three-stage, range 6-200

Torque: Same level as TQ

Applicable: In situations where installation space is limited but high rigidity is required, such as automatic guided vehicles (AGVs) steering and packaging machinery lateral axis.

4.3 TR and MP series (modular multiple choice)

TR: Back clearance ≤ 5arcmin (single-stage), outstanding load capacity (R ₂ max up to 14000N), optional coaxial, right angle input (K-G), right angle output (MB) and other layouts.

MP: Back clearance ≤ 15 arcmin (single-stage), more cost-effective, suitable for medium precision applications such as woodworking machinery and conveyors.

4.4 LC/LCK series (economically efficient)

Torque: 10~450Nm (LC 050~155)

Back clearance: ≤ 12 arcmin (single-stage)

Option P: Increase output torque by approximately 30% to 50%

Application: Equipment that is cost sensitive but requires reliability, such as automated assembly, packaging lines, labeling machines, etc.

4.5 KR series (compact and flexible)

Speed ratio: 1, 2, 5 (single-stage bevel gear)

Output format: Solid shaft (single/double output), hollow shaft (with locking disc or key)

Bearing: Standard ball bearing (SB) or reinforced tapered roller bearing (HB)

Features: IP65, lightweight, suitable for shuttle cars, elevators, and small rotating tables.

4.6 SL series (belt drive optimization)

The output end is specifically designed for installing synchronous pulleys, with strong radial load-bearing capacity.

Back clearance ≤ 6arcmin (single-stage), compact design, suitable for conveyor belt drive.

Precautions for installation and selection

5.1 Motor adaptation

Bangfeili offers a wide range of motor adapters (FM) that can be matched with mainstream servo motor brands such as Siemens, Fanuc, Yaskawa, and Beijare. When placing an order, please specify the motor model, shaft diameter, and installation hole spacing. You can also choose the adapter free version (IS) to directly customize the input shaft aperture.

5.2 Lubrication and Maintenance

S1 continuous working system: using ISO VG 220 synthetic oil; S5 intermittent working system: use NLGI 00 grease.

It has been filled at the factory and does not need to be replaced under normal working conditions (no pollution).

The ambient temperature should be between -20 ° C and+40 ° C (if it exceeds 30 ° C, the rating should be reduced), and the shell temperature should not exceed 90 ° C.

5.3 Protection level

Performance lines are mostly IP65 (dustproof and splash proof), Effective lines are mostly IP54 (dustproof and splash proof), and KR series are IP65.

5.4 Installation position

Each series supports multiple installation positions (horizontal, vertical, hanging, etc.), please refer to the installation position codes (ORVA, VB, etc.) in the manual for details. Please note that the oil seal and lubrication method may vary depending on the installation direction, and should be clearly specified when ordering.

Digital tools assist in selection

Bangfeili provides three online/software tools to accelerate the design process:

SERVOsft ®： Multi axis servo system selection, supporting 15 mechanisms and up to 50 axes, can simultaneously select motors, gearboxes, and drivers, and calculate dynamic response and energy consumption.

Mosaic 3.0: Product Configuration and Order Assistant, where you can input parameters online to obtain models, drawings, and 3D models.

EPLAN data: Provides device macro files to simplify electrical drawing design.

It is recommended that engineers use the above tools for verification after completing preliminary calculations and directly generate order codes (such as TQ 090 1 3 STD 50B CD 14 KE).

Practical engineering cases and common misconceptions

7.1 Case: Horizontal axis of packaging machine

Requirements: Output speed of 200rpm, load torque of 80Nm, occasional peak torque of 150Nm, radial force of 500N, ambient temperature of 40 ° C, and 200 start stop cycles per hour.

Motor speed 3000rpm → Speed ratio i=3000/200=15

Equivalent torque of 80Nm, peak value of 150Nm ＜ Ma2 (usually ≥ 2 times rated), temperature coefficient fT=0.9, speed coefficient fn=1, cycle coefficient fz ≈ 1.2

The required Mn2 is ≥ 80 × 0.9 × 1.2 ≈ 86Nm → TQ 090 2/15 (Mn2=155Nm) is selected to meet the requirement.

7.2 Misconceptions Reminder

Neglecting radial/axial force verification resulted in premature bearing damage.

Failure to consider the cyclic frequency coefficient in frequent forward and reverse rotation results in premature fatigue of the gear.

The ambient temperature is above 40 ° C without derating, resulting in insufficient thermal power.

Choosing too low a backlash may increase costs, and it should be reasonably selected based on actual positioning accuracy requirements (such as robots requiring ≤ 3arcmin, conveyor belts can be relaxed to 10arcmin).