FK UCPA 205 Pillow Block Bearing Unit – Technical Specifications, Construction and Industrial Applications. Among the commonly used bearing housing designs, the FK UCPA 205 bearing unit is an optimal solution widely applied in industrial equipment thanks to its space-saving design and stable operating performance.
1. Construction and Main Components of the UCPA 205 Bearing Unit
The FK UCPA 205 bearing unit consists of two main components manufactured in accordance with industrial standards:
PA 205 Bearing Housing: This is a compact pedestal-type housing without the conventional exposed mounting ears found on traditional UCP units. Instead, it features two threaded mounting holes integrated directly into the bottom of the housing. This design significantly reduces the overall width, allowing installation in confined spaces. The housing is manufactured from high-grade grey cast iron, providing good vibration-damping properties and high mechanical strength.
UC 205 Insert Ball Bearing: This is a single-row radial insert ball bearing featuring an extended inner ring on both sides. The outer ring has a spherical outside surface that matches the spherical bore of the bearing housing.
2. Standard Geometric Dimensions of the UCPA 205 Bearing Unit
All component dimensions are specified in the metric system and comply with industrial dimensional standards:
- Shaft bore diameter (d): 25 mm. This is the nominal diameter of the shaft to be installed.
- Shaft center height (h): 36.5 mm. The distance from the mounting base to the geometric center of the rotating shaft.
- Mounting hole center distance (e): 56 mm.
- Overall housing width (b): 40 mm.
- Overall base length (a): 84 mm.
- Overall unit height (w): 72 mm.
- Mounting bolt specification: M10 metric threaded holes, with thread depth designed to withstand standard tightening torque without thread deformation.
3. Load Ratings and Operating Characteristics
The load-carrying capacity of the UCPA 205 bearing unit depends on the load ratings of the UC 205 insert bearing:
Dynamic Load Rating (Cr): Approximately 14 kN. This represents the bearing’s capacity to withstand continuous operating loads at its rated rotational speed while achieving the required fatigue life.
Static Load Rating (C0r): Approximately 7.8 kN. This indicates the maximum permissible contact stress between the rolling elements and raceways when the bearing is stationary or operating at low speed.
Shaft Locking Mechanism: The bearing uses two set screws positioned at an angular offset of 120° on the extended inner ring. When tightened, these screws secure the bearing onto the shaft surface, helping prevent axial displacement and rotational slippage during operation and start-up.
Self-Alignment Capability: The spherical outside surface of the bearing’s outer ring allows the unit to compensate for angular misalignment of up to approximately ±2°, which may result from shaft deflection or installation inaccuracies in the supporting structure.
Sealing and Lubrication System: The bearing is pre-lubricated with specialized heat-resistant grease, with an operating temperature range of -20°C to +120°C. Both sides of the bearing are equipped with double sealing arrangements, combining rubber seals and metal shields to protect against dust and contaminants from the production environment. The PA 205 housing is also equipped with a metric grease nipple for periodic relubrication.
4. Industrial Applications and Actual Operating Conditions
Thanks to its compact pedestal design and flexible mechanical self-alignment capability, the FK UCPA 205 bearing unit is widely used in power transmission systems, material handling equipment, and automated production lines.
Industrial Conveyor and Chain Drive Systems:
In food processing plants, pharmaceutical packaging facilities, and logistics warehouses, installation space within machine frames is often restricted by the mechanical structure of the production line. The UCPA 205 bearing unit can serve as an alternative to conventional UCP units in suitable applications, including drive and idler conveyor pulley shafts for light- and medium-duty conveyor systems, intermediate support shafts in multi-stage transmission systems, and guide roller assemblies requiring stable operation.
Agricultural Machinery and Post-Harvest Processing Equipment:
Agricultural operating environments expose mechanical components to dust, plant fibers, and high humidity. The FK UCPA 205 bearing unit can be effectively used in rotating shafts of grain sorting machines, agricultural dryers, and screw conveyor systems transporting bulk materials such as bran, rice, and flour. Its concealed M10 threaded mounting holes on the underside eliminate exposed external mounting features, helping reduce areas where raw materials can accumulate and potentially cause mechanical blockage.
Packaging Production Lines and Digital Printing Industry:
These industries require high kinematic accuracy and effective control of roller shaft deflection. The spherical self-aligning design of the UC 205 bearing helps accommodate angular misalignment and reduce localized stress at the shaft support points when paper or plastic film rollers deflect under their own weight or web tension.
In addition, the two set screws positioned at an angular offset of 120° help prevent microscopic axial movement between the bearing and shaft, supporting stable shaft positioning and reducing the risk of misalignment or wrinkling of printed film materials.
5. Technical Installation and Maintenance Recommendations
To optimize the rolling fatigue life of the FK UCPA 205 bearing unit, installation and maintenance procedures should follow these technical recommendations:
Shaft Fit Tolerance: A shaft tolerance grade ranging from h6 to h8 is recommended, depending on the operating conditions and bearing manufacturer’s specifications, to ensure a suitable fit when securing the bearing with set screws. Excessive clearance may cause fretting wear between the bearing inner ring and the shaft surface.
Set Screw Tightening Torque: The hexagon socket set screws on the extended inner ring should be tightened using a calibrated torque wrench in accordance with the manufacturer’s recommended torque (approximately 4.5–5 Nm). This helps prevent damage or cracking of the inner ring.
Relubrication Interval: Under normal operating conditions (temperature below 50°C and low dust levels), lithium-based grease may be replenished every 6–12 months through the integrated grease nipple. Under more severe operating conditions, the relubrication interval should be shortened according to the actual operating hours of the equipment to maintain an effective lubricating film between the balls and raceways.
Conclusion
The FK UCPA 205 bearing unit is a complete mechanical assembly designed to meet demanding industrial requirements for dimensional accuracy and radial load-carrying capacity. Its compact pedestal design, combined with flexible self-alignment capability, makes it a suitable choice for engineers designing conveyor systems, packaging machinery, and precision mechanical transmission equipment.
