Bevel enclosed speed reducers help conveyor designers reduce motor speed and turn the drive through an angle within a protective gearbox housing. In a right-angle arrangement, the motor can sit alongside the conveyor rather than extending along the pulley axis. That layout can improve use of installation space, but a successful selection still begins with belt speed, effective belt pull and the load cycle.
This guide follows a conveyor application from the drive pulley back to the motor. It explains how to specify a bevel speed reducer, compare mounting arrangements and identify the information needed for a useful quotation.
What Does “Enclosed” Mean?
An enclosed reducer houses its gears and bearings inside a casing that supports alignment and contains the specified lubricant. Shaft seals and other sealing provisions help control leakage and contamination. The word “enclosed” does not establish a washdown rating, corrosion resistance or suitability for an explosive atmosphere. Those requirements need separate confirmation for the exact unit.
In a helical-bevel design, a bevel stage changes the direction of power transmission while helical stages provide additional reduction. The final shaft arrangement, ratio and mounting details depend on the selected configuration. When comparing right angle bevel speed reducers, use the dimensional drawing and technical data rather than relying only on a product-family name.
Calculate the Required Pulley Speed First
For a belt conveyor without significant slip, belt speed relates to pulley diameter and rotational speed:
Pulley speed in rpm = 60 × belt speed in m/s ÷ (π × effective pulley diameter in metres).
Use the effective driving diameter, accounting for lagging where relevant. If a chain or another transmission connects the gearbox to the pulley, include that additional ratio. Gearbox output speed equals pulley speed only when the connection is direct or has a 1:1 ratio.
Consider an illustrative conveyor with a 0.32 m effective pulley diameter, a target belt speed of 0.8 m/s and a motor operating at 1,470 rpm. The required pulley speed is about 47.7 rpm, giving an initial total reduction target of 30.8:1.
| Calculation | Example result | Selection implication |
|---|---|---|
| Pulley speed: 60 × 0.8 ÷ (π × 0.32) | Approximately 47.7 rpm | Establish the speed required at the pulley. |
| Total ratio: 1,470 ÷ 47.7 | Approximately 30.8:1 | Compare available ratios and any external transmission ratio. |
| Pulley torque at 4,000 N effective belt pull: 4,000 × 0.16 | 640 N·m | This is working torque at the pulley before additional allowances. |
| Mechanical power at the belt: 4,000 × 0.8 | 3.2 kW | Motor input must also cover drivetrain losses and the complete duty. |
These figures illustrate the method; they are not TOGINE product ratings or a completed drive selection. The example assumes steady motion and does not include acceleration, abnormal loading or an application-specific service allowance.
Effective Belt Pull Is Not Total Bearing Load
Effective belt pull represents the tension difference that produces drive torque. It should not be substituted directly for the total radial force on a pulley shaft. Both belt spans load the pulley, and their directions and tensions determine the resultant force.
Identify which bearings carry those loads. With a separately supported pulley and a suitably aligned coupling, the pulley bearings carry the belt forces. If the reducer output directly carries a pulley or sprocket, the reducer supplier needs the applied forces and their distance from the housing. Torque capacity alone cannot establish bearing suitability.
For shaft-mounted units, also review the driven shaft, gearbox weight and reaction support. A torque arm transfers housing reaction to the machine structure and must follow the supplier's installation arrangement. It is not simply an optional brace.
Choose a Mounting Arrangement That Can Be Serviced
| Arrangement | Potential benefit | Detail to confirm |
|---|---|---|
| Foot-mounted reducer with a coupling | Separates gearbox installation from the pulley support | Foundation stiffness, alignment and access for coupling inspection |
| Flange-mounted reducer | Can integrate with a machine support plate | Flange dimensions, support rigidity and mounting fasteners |
| Hollow-shaft reducer on the driven shaft | Can reduce the number of external transmission components | Shaft tolerances, retention, reaction support and removal space |
| Solid output shaft with a sprocket | Allows an external ratio or shaft offset | Chain forces, overhang, lubrication and bearing-load limits |
Compare the complete installed envelope, including motor, guards and service access. A unit that fits during assembly may be difficult to remove later if its shaft withdrawal space is blocked by a conveyor frame.
Review Loaded Starts and Variable-Speed Operation
A conveyor may run smoothly after reaching speed but require more torque to restart when loaded. Provide the supplier with acceleration time, starts per hour, maximum conveyed load and any expected shock loading. Confirm both the motor's available starting torque and the reducer's permitted peak torque under those conditions.
When a variable-frequency drive is involved, specify the full operating speed range. Operation at lower speed can change motor cooling and gearbox lubrication conditions, while higher speed can affect losses and permissible input limits. Request confirmation across the intended range, not only at the motor's nominal speed.
For an inclined conveyor, stopping and rollback requirements need their own assessment. A bevel speed reducer should not be assumed to hold a loaded belt when power is removed. A brake or backstop, where required by the machine design, needs a suitable rating, direction and operating arrangement.
Make Lubrication and Environment Part of the Inquiry
State the gearbox mounting orientation before the unit is specified. Oil level, vent location and lubrication provisions can change with orientation. Do not rotate an installed unit into a new position without checking the manufacturer's instructions.
Describe dust, moisture, washdown chemicals, ambient temperature and daily running hours. Ask for the applicable sealing provisions, lubricant and maintenance schedule. Maintenance intervals should come from the selected unit's instructions and operating conditions rather than a generic interval copied from another gearbox.
For a replacement, record whether the previous problem was overheating, leakage, output-bearing damage or insufficient starting torque. That history can expose a selection or installation issue that purchasing the same nominal power and ratio would leave unresolved.
Frequently Asked Questions
Are bevel enclosed speed reducers sealed for life? Not necessarily. Enclosed construction does not determine the lubrication schedule. Check the specified oil checks, changes and breather requirements.
Can right angle bevel speed reducers fit either side of a conveyor? Available arrangements vary. Confirm shaft projection, rotation direction, mounting position and service clearances on the approved drawing.
Is matching motor power enough when replacing a bevel speed reducer? No. Compare ratio, output torque, duty, bearing loads and mounting dimensions. Also check motor compatibility and the reason for the replacement.
What should I send for a quotation? Provide belt speed, effective pulley diameter, effective belt pull or calculated pulley torque, load cycle and an installation drawing. Include the motor details and operating environment. See our gearbox inquiry checklist or contact TOGINE to discuss the application and request confirmation of a suitable configuration.