In modern industrial automation, the performance of motion control systems often depends on the perfect coupling between motors and reducers. Bonfiglioli's BMS (Bonfiglioli Motion Solution) series precision planetary servo reduction motors are highly integrated products designed to meet this demand. It integrates a low backlash planetary gearbox with a high-performance permanent magnet synchronous servo motor, providing a compact and efficient driving solution for fields such as packaging, material handling, automatic warehousing, and textile machinery.
Chapter 1: Core Values and Technical Positioning of BMS Series
The BMS series is not just a simple combination of motor and gearbox, but a deeply optimized mechatronics solution.
1.1 Integration advantages
Compared to traditional split type motors and reducers, the integrated design of BMS brings significant competitive advantages:
Compact profile size: eliminates the need for adapter flanges and couplings between the motor shaft and gearbox input shaft, resulting in a significant reduction in overall length.
Optimized performance matching: Based on Bonfly's dual expertise in the fields of gearboxes and motors, the motor output characteristics of BMS have been accurately matched with the torque carrying capacity of the gearbox, avoiding performance redundancy or insufficiency caused by improper selection.
Higher rigidity and lifespan: The integrated shell design enhances overall rigidity, and thanks to optimized bearing layout, the BMS series can withstand higher radial and axial loads, resulting in longer bearing lifespan.
1.2 Application Scenarios
This series is designed for applications with high dynamic response and high-precision positioning. Whether it's stacker cranes in automated warehouses, cutting mechanisms on packaging production lines, or rotating axes around robots, BMS can provide precise power transmission. Its standard backlash is as low as 5 arcmin (single-stage), while the optional low backlash version can be controlled within 3 arcmin, which is a key physical indicator to ensure positioning accuracy.
Chapter 2: Selection Calculation: From Application Parameters to Specific Models
The correct selection is the cornerstone of stable equipment operation. Bangfeili provides a rigorous selection methodology, the core of which is to determine the most suitable model based on the torque speed curve of the load.
2.1 Analysis and Calculation of Operating Conditions
Firstly, it is necessary to analyze the duty cycle of the application. For example, if the device includes long-term constant speed operation and short-term acceleration and deceleration within a cycle, it is necessary to calculate the torque requirements for different stages separately M two(i) M 2(i).
According to the selection process diagram in the document (Chapter 12), we need to first calculate the cycle duration factor ED%
ED%=t one+t two+⋯+tn
Total cycle time×one hundred%
ED%= Total cycle time
t one+t two+⋯+t n ×100%
S1 working system (continuous operation): If ED% greater than 60% or a single run time that is too long is usually considered a continuous working system.
S5 working system (intermittent operation): If ED% If the ED% is less than 60% and the single operation time is short, it is considered as an intermittent working system.
2.2 Verification of Peak Torque and Equivalent Torque
Peak torque(M two PEAK M 2 PEAK)Must be less than or equal to the maximum acceleration torque allowed by the gearbox M two
This is the first line of defense to protect gears from impact damage.
Equivalent torque(M two EQU M 2 EQU)For variable load conditions, it is necessary to calculate the root mean square torque. The formula is as follows:
M two EQU=M two(one) two⋅t one+M two(two)two⋅t two+…t one+t two+…
M 2 EQU= t one+t two+…M 2(1)two⋅t one+M 2(2) two⋅t two+…
This value must be less than the rated torque of the gearbox
M n two M n2 To ensure that overheating does not occur during long-term operation.
2.3 Verification of output speed
Confirm the maximum speed of the application n max
Do not exceed the maximum allowable input speed (considering speed ratio) or output speed of the gearbox. If the speed is too high, a larger gear ratio (i) or a larger specification gearbox should be selected.

Chapter 3: In depth Interpretation of Key Performance Parameters
Understanding several key parameters is crucial for selection when consulting BMS performance data sheets.
3.1 "Overspeed Variants"
The BMS series offers three "overspeed" variants for the same motor: BASE, MEDIUM, and HIGH (B, M, H) (Chapter 18).
Core logic: These three variants are essentially different in the winding characteristics of the motor.
B-type (Base): Optimized for conventional speed applications, with low current consumption and high cost-effectiveness.
H-type (High): can provide higher maximum speed at the same voltage n a two n a2
Suitable for application scenarios that require high-speed operation.
Selection influence: Choosing a higher overspeed variant can increase the maximum speed, but the rated torque
Mn two M n2 Usually unchanged and requires the driver to provide higher peak current Ia
Engineers need to strike a balance between speed and drive capacity.
3.2 Bearing Life Calculation
The bearing life of the output shaft is an important indicator for measuring the reliability of the gearbox. In BMS, in addition to radial force
R two And axial force A two
We also need to consider the overturning moment M T two M T2
Calculate equivalent overturning moment MT two EQUM T2EQU
The formula takes into account the force arm xX and L two
Waiting for installation size factors:
MT two
EQU=R two EQU⋅(x+Ltwo)+Atwo
EQU⋅y one thousand
M T2EQU= one thousand R 2EQU⋅(x+L two)+A 2EQU⋅y
Then use the basic rated life formula of the bearing:
Lten h=sixteen thousand six hundred and sixty-six n two
EQU(CBMT two EQU)pL 10h= n 2EQU sixteen thousand six hundred and sixty-six( M T2EQU C B ) p
Through this formula, it is possible to reverse validate the required size of gearbox based on the expected lifespan target (such as 20000 hours). The document provides information on BMS 060 to 160 models
CB(Bearing constant) and index P-value.
Chapter 4: Feedback Device, Braking and System Integration
As a complete driving unit, the core advantage of BMS lies in its seamless integration with Bonfiglioli Vectron ACTION series frequency converters.
4.1 Feedback device selection
To meet different control accuracy requirements, BMS provides multiple feedback options (Chapter 38):
Resolver: Standard solution, using RES1 or RES2 interface. The rotary transformer has extremely high resistance to vibration and high temperature, suitable for use in harsh environments, and its position information is single turn absolute.
EnDat and Hiperface encoders: providing optical or capacitive encoders for applications that pursue high precision and high response.
ENB1/ENB2: Using Heidenhain EnDat protocol, providing absolute position information for single and multiple laps.
ENB3/ENB4/ENB5: Adopting SICK Hiperface protocol.
4.2 Thermal protection and brake configuration
Thermal protection (Chapter 40): The built-in PTC thermistor (150 ° C jump) or KTY sensor ensures safe operation of the motor winding within the F-class insulation (155 ° C) limit. When setting parameters, it is necessary to set the analog input of the frequency converter (such as the Active series MFI1A) to the corresponding sensor type.
Brake (Chapter 41): The BMS can be equipped with a permanent magnet brake, specifically designed for power-off holding (Holding Brake). Attention: The braking torque of the brake should be multiplied by the speed ratio to obtain the output shaft braking torque(
Mb two=Mb×iM b2=M b(x i). This brake is not recommended for use as a dynamic deceleration brake (except in emergency situations).
4.3 Cable and Connection System
BMS adopts a standardized connection system that complies with DESINA standards, greatly simplifying wiring work.
Power cord (orange): Integrated with motor power cord and brake wire (if any).
Signal line (green): used to transmit feedback device signals and thermistor signals.
Selection tip: Bangfeili provides prefabricated cables with standard lengths of 3 meters, 5 meters, and 10 meters, and is available with straight heads and elbows (AN type) for selection. The use of shielded prefabricated cables is key to ensuring EMC performance and signal integrity.
