In heavy industries such as mining, building materials, metallurgy, and ports, the HDP (Heavy Planetary) and HDO (Heavy Spiral Cone Gear) series gearboxes have become the core components of critical transmission equipment due to their high power density and excellent reliability. However, even the highest quality equipment can still lead to early failure if installed improperly or maintained improperly. This article is based on Bonfiglioli's official "Installation, Operation, and Maintenance Manual for HDP/HDO Series", providing on-site engineers with full process technical guidance from unboxing inspection to troubleshooting.
Safety regulations and operational prerequisites
1. Personnel qualification requirements
All personnel engaged in the installation, maintenance, and repair of gearboxes must undergo professional training, possess corresponding skills and experience, and be equipped with appropriate tools and personal protective equipment. Unauthorized personnel are not allowed to perform any operations on the gearbox.
2. Operational restrictions
Gearboxes can only be used within the industrial application scope specified by the manufacturer.
Changing the installation position or configuration of the gearbox without authorization will invalidate ATEX certification.
During operation, the surface temperature of the shell shall not exceed the ambient temperature of 75 K (Δ T). If this value is exceeded, the machine should be stopped immediately and the manufacturer's technical support should be contacted.
3. Surface high temperature risk
The outer surface of the gearbox may reach a high temperature of 135 ° C during operation. Before maintenance, it is necessary to wait for the equipment to cool down sufficiently or wear heat-resistant gloves.
Handling and unpacking inspection of goods
1. Arrival inspection
After receiving the goods, check whether the shipping list matches the order information and inspect the gearbox for any transportation damage. If there are any issues, please contact the Bonfiglioli dealer immediately.
2. Lifting safety
The rated load of certified lifting devices such as eyebolts, shackles, and steel cables must be greater than the weight of the lifted object.
It is strictly prohibited to use the lifting ring bolts on the motor housing to lift the gear motor.
During the lifting process, the load swing shall not exceed ± 15 °.
Additional accessories (such as connecting flanges) or motors may significantly change the center of gravity, and additional suspension points may be added if necessary.
3. Storage requirements
Store in a dry and covered place, with temperature range specified in the "Allowable Temperature Limits" section of the manual.
The relative humidity should not exceed 80% to avoid condensation caused by drastic temperature changes.
When stored for more than 6 months, it is necessary to apply anti rust products on the external machined surface and regularly rotate the input/output shaft to prevent damage to the bearings and seals.
Key installation processes
1. Preparation before installation
Drain the storage oil (if incompatible with the working oil) and thoroughly clean the inside of the gearbox.
Remove all packaging and protective coatings to avoid solvent contact with the shaft seal.
Confirm that the nameplate data is consistent with the order, including the installation location.
The installation base must have sufficient rigidity and flatness.
After cleaning the mating surface, apply anti micro corrosion protective paste (such as Kl ü berpaste 46 MR 401).
Connect the gearbox housing to the equipment grounding circuit.
2. Solid shaft installation
It is strictly prohibited to forcefully install external transmission components using tools such as hammers.
Use the bolts and washers shown in the diagram to assist in installation and avoid damaging the bearings.
When installing the transmission mechanism with asymmetric wheel hubs, use the recommended configuration to minimize bearing loads.
3. Installation of hollow shaft with keyway
Insert the gearbox into the customer's shaft and install the axial fixing device to prevent accidental detachment.
Screws and washers are not provided randomly and need to be prepared by oneself.
4. Installation of shrink disc (key process)
Shrinkage disc is the most common coupling method for shaft mounted gearboxes, and the installation quality directly affects the torque transmission capacity:
Cleaning and degreasing: Clean and degrease the holes inside the gearbox and the outer surface of the customer shaft. It is strictly prohibited to use molybdenum disulfide or other lubricating grease to avoid reducing the friction coefficient.
Installation steps:
Remove the protective cover, gradually loosen the shrink plate bolts (do not completely remove), and remove the shrink plate.
Insert the gearbox into the machine shaft.
Install the recycling tray and gradually tighten the bolts in a clockwise sequence, repeating multiple times until the specified torque is reached.
Installation torque reference table (example): HDP 60/HDP 70 is 35 Nm; HDP 130/HDP 140 is 490 Nm.
ATEX requirement: When reinstalling the protective cover, apply Loctite 5366 to the centering and end fitting surfaces, and Loctite 510 to the bolt threads.
Disassembly tip: If disassembly is difficult, you can use the oil pressure injection hole (1/8 "or 1/4" BSP) on the gearbox to inject pressurized oil for assistance.
Special requirements for ATEX explosion-proof environment
For gearboxes designated for use in potentially explosive environments, the following requirements must be strictly followed:
Only synthetic lubricants (PAG or PAO) are allowed, mineral oils are not suitable.
Only fluororubber (Viton) is allowed to be used ®) Sealing element.
All external bolts and plugs must be coated with thread locking adhesive.
Equipped with breathable plugs with anti intrusion valves.
Install irreversible thermal sensors (TG or PT100) to monitor oil temperature.
Regular cleaning plan: Gearboxes installed in zones 21/22 must undergo regular cleaning to prevent dust accumulation exceeding 5mm.
After installation, thoroughly clean the gearbox and ensure that all protective devices are installed in place.
Only install motors with ATEX rating not lower than the gearbox.
The motor shall not exceed the maximum input speed of the gearbox (1500 min ⁻¹).

Lubrication management
1. Lubricating oil selection
Only use lubricants recommended by the manufacturer (synthetic oil PAG/PAO or mineral oil with EP additives).
It is strictly prohibited to mix different brands or specifications of oil products.
Recommended synthetic oil brands include Shell Omala S4 WE (PAG), Shell Omala S4 GVX (PAO), Mobil SHC Gear, Kl ü bersynth GH 6, etc.
2. Oil change cycle
The oil change interval depends on the type of oil and operating temperature:
Average oil temperature mineral oil PAO synthetic oil PAG synthetic oil
< 65°C 8,000 h 25,000 h 25,000 h
65-80°C 4,000 h 15,000 h 15,000 h
80-95 ° C 2000 h (within 1 year) 12500 h 12500 h
It is not recommended to operate continuously within the oil temperature range of 80-95 ° C. Oil temperature exceeding 95 ° C is considered a fault state.
3. Oil filling
The gearbox does not contain lubricating oil when it leaves the factory (unless specifically specified at the time of ordering). Users need to add the corresponding amount of oil according to the installation position on the nameplate and the oil level table in the manual. The table data is for reference only, and the actual value is based on the oil level plug mark or the midpoint of the oil gauge.
4. Replacement of breathable plug
The gearbox is equipped with a closed transport plug when it leaves the factory. Before formal operation, it must be replaced with the breathable plug that comes with the box, otherwise the internal pressure will increase and cause damage to the oil seal.
Auxiliary cooling/heating system configuration
1. Compulsory ventilation (FANL/FANR/FANLR - FAN/FANJ)
The fan is directly installed on the input shaft and protected by a protective cover.
It is strictly prohibited to operate the gearbox without installing the fan protective cover.
When the input speed is below 900 min ⁻¹, the forced ventilation efficiency significantly decreases, and auxiliary cooling devices need to be considered.
Regularly clean the dust on the fan blades and protective grille.
2. Independent cooling units (MCRW.../MCRA...)
MCRW (water oil cooler): equipped with electric pump, filter, water oil heat exchanger, solenoid valve, and temperature controller. Cooling water temperature ≤ 20 ° C, maximum pressure 10 bar.
MCRA (Air Oil Cooler): Equipped with an electric pump, filter, air oil heat exchanger, and fan. Ensure at least 1 meter of free space around the heat exchanger to ensure air circulation.
Control logic: Start cooling when the oil temperature reaches 60 ° C; Trigger an alarm and shut down as soon as possible when reaching 90 ° C.
ATEX components: Please refer to the manufacturer's separate catalog and manual.
3. Cooling coil (SR)
Non removable cooling coil installed in the gearbox oil tank.
Cooling water temperature ≤ 20 ° C, maximum pressure 8 bar. Flow requirement: HDP 60-90 is 5 L/min; HDP 100-140 is 10 L/min.
It is recommended to install a thermostatic valve in the cooling water circuit and only allow water to flow when the oil temperature reaches 70 ° C.
4. Oil heater (HE)
Used when the ambient temperature is too low and the oil viscosity is too high (oil viscosity exceeds 1500 cSt at startup).
The heating element is installed below the oil level, and the standard power supply is 220V AC.
The heater must be turned on only when the oil completely covers the heating element, and should only be used during preheating. It should not be powered on for a long time to prevent oil carbonization.
The thermostat setting temperature is usually 25 ° C ± 5 ° C.
Long Term Stock
For gearboxes with a storage period exceeding 6 months (up to 2 years):
Packaging: The gearbox is sealed in a VpCI rust proof bag, and the outer packaging is a BBOX cardboard box or wooden box labeled "OPEN ONLY BEFORE THE INSTALLATION".
Rust proof fluid: Add anti-corrosion protective fluid internally instead of standard lubricating oil.
Compatibility:
SLM option: Rust inhibitor is compatible with all mineral oils and PAO synthetic oils.
SLP option: Rust inhibitor is compatible with all PAG synthetic oils.
Pre operation treatment: If the working oil is compatible with the rust inhibitor, simply add the working oil and replace the breathable plug; If not compatible, first drain the rust inhibitor, add 20% oil for "cleaning operation", and then add new working oil after draining.
After storing for 2 years, it needs to be inspected by Bonfiglioli service center before it can be stored for another 24 months.
Backstop and torque arm
1. Reversing device (A CW/A CCW)
Ensure that the gearbox rotates only in one direction to prevent load reversal.
It is strictly prohibited for the motor to rotate in the opposite direction, otherwise it may damage the backstop or gear system.
When running continuously, it is recommended to input a speed higher than the minimum exceedance speed (n1min) specified in the manual to ensure the normal operation of the centrifugal separation mechanism.
2. Torque arm (TA)
Shaft mounted gearboxes need to be equipped with torque arms to withstand counter torque.
The torque arm must be installed stress free during installation and adjusted according to the specified gap G before starting.
Regularly check the wear of the cup-shaped spring and the condition of the polymer liner (aging, cracking).
Common faults and troubleshooting
Possible causes and solutions for the fault phenomenon
Bearing temperature too high, oil level too low, oil aging, bearing failure, oil replenishment, oil change, contact authorized maintenance
Operating temperature too high, oil level too high, oil aging, oil pollution. Check oil level, change oil, change oil
Abnormal operation noise, gear damage, excessive bearing clearance, bearing wear, overload, contact authorized repair, load correction, oil change
Abnormal noise at the installation site. Loose or worn installation bolts. Tighten and replace bolts according to the specified torque
Oil leakage, high oil level, seal failure, gasket aging. Check the oil level and contact authorized maintenance
The gearbox does not rotate or has difficulty operating. The oil viscosity is too high, the oil level is too high, it is overloaded, the gear is damaged, the oil needs to be replaced, the oil level needs to be checked, the transmission needs to be redesigned, and authorized maintenance needs to be contacted
Key nodes of maintenance plan
Every 24 hours: Check the oil pressure (if there is a hydraulic circuit), noise, and vibration.
Every 720 hours: Check for external seal leaks, oil level, and oil filter contamination indicators.
Every 2000-4000 hours: Check the torque of all fastening bolts, wear of coupling elastic components, and re lubrication of Drywell seals.
Every time the oil is changed: check the alignment status between the gearbox and the coupling equipment.
Every 5000 hours: Replace synthetic oil and bearing grease (non lifetime lubrication type).
Surface temperature measurement: During the first operation, measure the surface temperature of the shell after continuous full load operation for 3 hours, and Δ T should not exceed 75K.
