AHB vs AHL Series Planetary Gearboxes: Choose Standard Precision or Heavy-Duty

During production line commissioning, the drive choice often comes down to two reducers on the same spec sheet: the AHB and the AHL from ZHEJIANG BEITTO TRANSMISSION TECHNOLOGY CO., LTD. (BEITTO). Both are precision planetary gearboxes, but they are not interchangeable. The AHB is a standard precision planetary reducer built for automation equipment and servo-driven axes, while the AHL is a heavy-duty helical-tooth planetary gearbox engineered for continuous high-torque operation. In this AHB vs AHL comparison, the wrong selection creates backlash errors in one machine and premature gear wear in another.

What Sets the AHB and AHL Series Apart at a Glance

The AHB is the standard precision choice for automation equipment, while the AHL is the heavy-duty helical-tooth option for machines that need higher torque and long-term stability. A planetary gearbox is a compact speed reducer that uses a sun gear, planet gears, and a ring gear to multiply motor torque while reducing speed. BEITTO builds both series with Japanese fine-engineering processes, but the gear geometry separates them.

The AHB uses an optimized tooth profile that keeps backlash in the class of 3 to 5 arcmin, which is ideal for fast positioning. The AHL uses helical teeth, which keep more than one tooth in mesh at all times, increasing the contact ratio and spreading the load across a wider area. BEITTO has documented the AHB series in automation equipment and the AHL series in long-term stability applications, and the two series serve different operating philosophies.

• AHB prioritizes positioning accuracy over torque margin.
• AHL prioritizes torque density and load capacity over micro-backlash.
• Both series pass the same quality control in the 12,000-square-meter BEITTO factory with 20-plus years of gearbox experience.

Core Technical Differences: Backlash, Torque, and Gear Geometry

The practical differences between the AHB and AHL series are the backlash class, the torque density per frame size, and the gear cut. The table below shows typical values for equal frame sizes.

The numbers above are typical for the same mounting frame. The AHL carries roughly 30 to 40 percent more torque, which is why it is the safer recommendation when the load profile includes shock loads or operation near the rated torque, a point confirmed in BEITTO load-characteristics guidance.

Load Characteristics: The Real Selection Driver

Load characteristics, not the machine type, decide whether you need AHB or AHL. Most gearbox failures come from selecting on peak torque while ignoring root-mean-square torque and duty cycle. A servo indexing table runs 30-second cycles with high acceleration demands; its RMS torque stays moderate, so the AHB works. A scrap conveyor runs 6,000 hours per year with a constant 80 percent rated load; the torque is present for the whole shift, so the AHL is correct.

Application Scenarios: Where Each Series Performs Best

Use the AHB series for precision automation and short-cycle positioning; use the AHL series for heavy conveyors, long-running process equipment, and any machine where torque is present for most of the operating shift.

If the machine uses a servo motor and stops for 40 percent of the cycle, choose AHB. If the motor runs continuously and the load does not drop below 50 percent of rated torque, choose AHL. These two application profiles correspond directly to the BEITTO documentation on automation equipment and heavy-duty operation.

Cost, Maintenance, and Supply Considerations

The AHB is cheaper in first cost and appropriate for standard duty cycles; the AHL is more expensive initially but can reduce maintenance events and energy consumption in continuous heavy-duty service. Do not fall for the price-per-unit trap. A 20-percent price premium on a gearbox that runs 6,000 hours per year is repaid quickly if the gearbox fails once less every two years.

Low Backlash AHB Planetary Gearbox for Standard Duty CyclesThe AHB planetary gearbox features helical gears with backlash under 3 arcminutes, integral roller bearings for high rigidity, and a flange mount compatible with global motors. Its grease is sealed for life, reducing maintenance. Ideal for standard duty cycles where cost and availability are priorities.View Product →

As a supplier, ZHEJIANG BEITTO TRANSMISSION TECHNOLOGY CO., LTD. (BEITTO) also looks at the supply side: standard frame sizes of the AHB are easier to keep in stock, while the AHL can be made on order with a longer lead time. In a new machine design, that lead time difference is a procurement risk you cannot ignore.

High Rigidity AHL Planetary Reducer for Continuous Heavy-Duty ServiceThe AHL series planetary reducer uses helical gears and integral ball bearings to deliver high torque and rigidity, suitable for demanding continuous operation. It offers flexible mounting options and a design that minimizes maintenance needs, though it is made to order with longer lead times.View Product →

How to Choose Between AHB and AHL: A Step-by-Step Framework

Start with the output torque and duty cycle, then check the backlash requirement, and only after that compare frame size and cost.

1. Calculate peak and RMS torque at the output shaft. Include acceleration and deceleration torque from load inertia.
2. Define the duty cycle in hours per day and cycles per hour. A continuous 24-hour machine shifts the selection toward AHL.
3. Set the maximum allowed backlash. If positioning repeatability is under 5 arcmin, AHB is the more direct answer.
4. Filter by torque margin. An AHB with less than 25 percent margin over RMS torque is a warning sign; the AHL is the better structure.
5. Verify frame size, input speed, and mounting pattern. Both series share standard flanges, but the AHL output shaft can be thicker at the same frame size.
6. Confirm the choice with the BEITTO engineering team using your real load diagram.

Frequently Asked Questions About AHB vs AHL Series

Final Recommendation

Choose the AHB when you need precise short-cycle positioning under moderate load; choose the AHL when your machine runs continuously under high torque. Both series are manufactured by ZHEJIANG BEITTO TRANSMISSION TECHNOLOGY CO., LTD., a factory in Pinghu, Zhejiang, with 12,000 square meters of production space and more than 90 employees. Every AHB and AHL gearbox passes the same quality control process, but the design intent is different.

If the selection still feels ambiguous, send the load diagram and duty cycle to the BEITTO engineering team for a free review. The correct series usually becomes clear once the RMS torque and peak shock torque are on the table.