6.2.2 RF Bearing Roller Conveyor Chain
Large conveyance: High performance chain. General uses
RF Bearing Roller Conveyor Chain is used in automobile, steel, electric, and other industries.
Figure 6.4 RF Bearing Roller Conveyor Chain
Figure 6.5 RF Bearing Roller Conveyor Chain Includes Cylindrical Roller Bearings
Construction and Features
Compared to basic RF Conveyor Chain, RF Bearing Roller Conveyor Chain has the following features:
- The coefficient of rolling friction for RF Bearing Roller Conveyor Chain is one-third to one-sixth that for RF Conveyor Chain.
Basic RF Conveyor Chain: without lubrication, 0.13 to 0.18; with lubrication, 0.08 to 0.12.
RF Bearing Roller Conveyor Chain: 0.03.
This means the chain tension is reduced, and, frequently, a smaller chain size can be used. The conveyor will also require less energy to operate, making it more economical.
- The initial cost of equipment is reduced. Because the coefficient of rolling friction is lower, you can use smaller sprockets, motors, reducers, shafts, bearings, and frames.
- The allowable load of the roller is increased. The allowable roller load for RF12000-R Bearing Roller Conveyor Chain is 8.35 kN, which is 1.6 to 3.3 times greater than the equivalent size of a basic type with lubrication (2.50 kN for nonheat-treated roller; 4.17 kN for heat-treated roller). Capacity of the roller for RF12000-R Bearing Roller Conveyor Chain is equivalent to RF26200-R Conveyor Chain with heat-treated rollers. This is two sizes larger. In horizontal and slightly inclined conveying, usually the chain size is determined by the allowable load of the roller. Because of the reasons we have discussed, you can select a chain two to three sizes smaller. Rollers are also exposed to high load when they engage with sprockets. Even though this load may be several times greater than the vertical load on rollers during conveying, it is within the capacity range of bearing rollers.
- Lower maintenance. RF Bearing Roller Conveyor Chain has grease pockets on both its sides. Although we have received reports that these chains have been operated for five years without any maintenance, we suggest that you lubricate the bearing roller occasionally.
- Longevity of the bearing roller. The bearing roller is large in diameter and short in length; therefore, failure due to foreign material getting inside it is rare. Some types of roller bearings are prone to failure due to foreign objects causing misalignment.
- Accepting thrust load. A self-lubricating spacer is installed on both sides of the roller to accept thrust load. The spacer prevents a direct contact between the rotating roller and the side plate; therefore, wear particles getting inside the bearing is minimized.
- Stick-slip resistance. Stick slip is virtually eliminated because of the low coefficient of friction in a wide range of speeds. Consult the manufacturer when conveyor speed is less than 2 m/min.
- Wide range of chain sizes is available. The ball bearings commonly available on the market cannot be adapted for the needs of chains due to their limited load capacity. It is difficult to adapt ball bearings to rollers with diameters less than 45 mm, but roller bearings can be adapted for use by using the bushing and roller as bearing races.
The standard sprockets used for RF Conveyor Chain are used for RF Bearing Roller Conveyor Chain.
Selection and Handling
- The design of standard bearing-roller spacers is similar to spacers used in ordinary ball bearings. They are not water- and dust-proof. Oil- or labyrinth-seals can be installed (on a made-to-order basis) if the chain is going to be exposed to water or dust. Please consult the chain manufacturer.
- A grease nipple can be installed on the pin head to provide grease to bearing parts (only certain sizes are available).
- The working temperature is limited to −20° to 80°C. The limiting factor is the spacer. When a temperature-resistant material is used for the spacer, operating temperatures may be expanded. Contact the manufacturer for additional information.
- To reduce the impact of the bearing roller as it engages the sprocket, use sprockets with greater numbers of teeth. For example, if the chain speed is 30 m/min., use a 10-tooth sprocket. Consult with the manufacturer if the chain speed is greater than 30 m/min.
- Do not select Bearing Roller Chain based on roller allowable load alone. In some applications, you also need to verify the strength of attachments to prevent breakage. Refer to the manufacturer's catalog for additional information.
Chains for Special Applications
- Outboard Bearing Roller Conveyor Chain is used on assembly lines (Figure 6.6). In this type of chain, bearing rollers are installed on the outside of the chain, making it ideal on long assembly lines, like auto lines, where work is performed on the conveyed products along the line. Outboard Bearing Roller Conveyor Chain is easy to support on the return side. If you combine the design features of Outboard Bearing Roller Conveyor Chain and Bearing Bush Chain, you can create a chain with very, very low elongation (practically nonexistent) and minimal rolling friction.
- Waterproof-bearing Roller Conveyor Chain (Figure 6.7) has heat-treated bearings made of 403 stainless steel, and includes oil-seals and grease nipples. Originally this chain was developed for the "shower test," which checks the leakage in automobile manufacturing. It can be used in any application where the chain is exposed to water spray.
NOTE: Charge with grease regularly.
Figure 6.6 Outboard Bearing Roller Conveyor Chain
Figure 6.7 Waterproof-bearing Roller Conveyor Chain
- Plastic sleeve type. Installation of plastic sleeves between the pins and bushings makes Bearing Roller Chain maintenance free. It also reduces the allowable tension. It is available in the following sizes: RF03, RF05, RF450, and RF10.
- A variety of attachments, including special attachments, can be installed on RF Bearing Roller Conveyor Chain.
Because of the lower initial cost of the entire installation, RF Bearing Roller Conveyor Chain has gained acceptance in a wide range of applications. Further series development is required to respond to various applications.