When selecting, it should be noted that the speed ratio directly affects the mechanical efficiency and heat generation of the gearbox. According to the empirical data in the manual, when the speed ratio of a planetary gearbox increases, the number of gear stages correspondingly increases, and the efficiency will slightly decrease. For continuous heavy load crushing conditions, it is recommended to prioritize the lower speed ratio scheme (such as i ≈ 56-80) to reduce internal heating and improve transmission efficiency.
2.3 Step 3: Determination of Input Driver Mode
One of the biggest features of the R3 series is its highly flexible input interface, which is also an important reason why it is widely favored in the OEM market for crushers.
A. Hydraulic motor drive scheme
According to the preset interface table provided in the manual, the R3 series supports direct installation of various mainstream axial piston hydraulic motors from the factory, including:
Bosch Rexroth A6VM series (such as 160, 215cc/rev)
Sauer Danfoss H1B series (e.g. 160, 250cc/rev)
Sauer Danfoss 51V series (e.g. 250cc/rev)
The manual provides a detailed list of interface size parameters for each hydraulic motor configuration, including key installation dimensions such as A, B, C, D, E, F, G, H, I, L, M, N, and R. This "plug and play" design greatly simplifies the power head integration of hydraulic driven crushers, reduces the need for intermediate transition brackets, and improves the spindle centering accuracy.
Selection Tip: If you plan to use hydraulic motor models not listed in the manual, Bonfiglioli's technical department can provide customized interface evaluation services.
B. Motor drive scheme
For fixed crushing stations driven by electricity, the R3 series also supports customized adaptation of IEC standard motor flanges or NEMA standard motors. The manual clearly states that this is an 'on-demand request', which means that it is necessary to communicate the motor power, flange specifications, and shaft extension dimensions with the Bonfiglioli engineering team in advance to ensure the integrity and reliability of the power transmission path.
Step 4: Matching the output interface with the crushing rotor
The connection method of the broken rotor is another key technical decision point in the selection process. The R3 series offers the following two standard output solutions:
Shamrock solid output shaft: This irregular cross-section shaft design has a large mating surface with the crusher rotor, which can effectively transmit high torque while avoiding stress concentration in the keyway. Especially suitable for working conditions with frequent heavy load startup and forward/reverse switching.
Splined output shaft: Suitable for scenarios that require axial sliding fit or quick tool replacement, the spline connection has the advantages of good centering and uniform load-bearing.
In addition, the R3 series also offers a Plug in output flange option, allowing for the replacement of worn rotors or tool holders without disassembling the gearbox, significantly reducing maintenance downtime.

Integrated precautions in primary crushers
3.1 Engineering verification of impact resistance capability
Although the R3 series has inherent impact resistance advantages in planetary transmission design, the following aspects still need to be considered in practical engineering integration:
Coupling selection: It is recommended to install a torque limiting coupling or hydraulic torque limiter at the input end of the gearbox to achieve overload disengagement when unbreakable objects enter the crushing chamber, protecting the internal gear ring and planetary carrier of the gearbox.
Supporting structure stiffness: The radial force on the crusher spindle will be transmitted to the gearbox housing through the output bearing. It should be ensured that the frame has sufficient rigidity to avoid excessive bending deformation of the gearbox housing, which may affect the internal gear meshing accuracy.
3.2 Special Requirements for Lubrication and Cooling
The primary crushing condition is usually continuous operation and the environment is dusty. As a heavy-duty application gearbox, the R3 series has been filled with special lubricating oil at the factory, but attention should be paid to the following during on-site installation:
The manual provides lubricant quantity and dry total weight data for each model, which users should use as a basis to check the oil level before the first operation.
It is recommended to install a temperature sensor on the gearbox housing to monitor the temperature rise of the lubricating oil. When the oil temperature continues to exceed 85 ° C, it is necessary to consider increasing forced cooling or increasing the tank capacity.
For dusty environments, double lip oil seals or additional dust-proof sealing rings should be used to prevent dust from entering the box and causing lubricant contamination and abnormal gear wear.
3.3 Technical value of pre-sales and after-sales support
The manual emphasizes a key point that is often overlooked in engineering procurement: the highly customized nature of the R3 series requires deep interaction between customers and the Bonfiglioli team from the design stage. This is particularly important for primary crushing equipment, as the rotor inertia, starting frequency, material characteristics, and installation space of each crusher may vary greatly.