EP-B4 Four-Stage Bevel-Helical Right-Angle Gearbox
The most powerful right-angle gearbox in the HB series — four stages, up to 500:1 ratio and 500 kNm, for the heaviest right-angle industrial drives. Sizes 5–26.
Product Overview: Maximum Right-Angle Power Transmission
The EP-B4 is the four-stage apex of the Ever Power HB bevel-helical right-angle gearbox series. One precision spiral bevel stage — which delivers the 90-degree shaft direction change — is followed by three carburised and ground helical reduction stages to produce overall speed ratios of 50:1 to 500:1 and a maximum nominal output torque of 500 kNm at the largest frame (Size 26).
No other single-housing right-angle gearbox in the HB series can match this combination of ratio depth and torque capacity. The EP-B4 is engineered specifically for the applications where right-angle shaft geometry is a physical layout requirement, not a preference — and where the speed reduction needed far exceeds what two- or three-stage units can deliver.
Available in sizes 5 through 26 across three dimensional groups, with the same nine standard mounting configurations (BSH through BDV) as the rest of the B series, the EP-B4 provides engineering teams with a catalogued solution for the most demanding right-angle drives in cement, mining, steel, port machinery, and large chemical process installations.
Four-Stage Right-Angle Engineering: Why It Matters
The challenge of a four-stage bevel-helical gearbox is not simply adding stages — it is maintaining the mechanical quality (alignment, tooth contact, bearing preload) through a gear train that changes direction once and then reduces speed three more times, all within a single sealed housing.
The bevel first stage sets the quality baseline. A poorly cut or misaligned bevel pair generates vibration that propagates through all downstream stages, increasing noise, reducing gear and bearing life, and causing premature fatigue failures. In the EP-B4, the bevel gears are precision-ground and individually lapped to achieve tooth contact patterns that cover 70–80% of the tooth face under load — the hallmark of a correctly manufactured and assembled spiral bevel stage.
The three downstream helical stages are then designed as a matched set, with gear ratios distributed to keep tooth loads, pitch line velocities, and thermal contributions balanced across all three meshes. This avoids concentrating heat generation in a single stage — a common failure mode in hastily designed multi-stage units.
The result is a right-angle gearbox that, at 500:1 ratio and 500 kNm output, delivers approximately 94–95% overall efficiency — far superior to any worm-gear right-angle alternative in this torque and ratio class, and comparable to a four-stage inline helical unit of the same power rating.
Size, Torque & Ratio Range
EP-B4 spans sizes 5 through 26 — the broadest size range in the four-stage bevel-helical class:
| Size | Nom. Output Torque (kNm) | Max Input Speed (rpm) | Ratio Range (i) | Applications |
|---|---|---|---|---|
| 5 | 0.80 | ≤1500 | 50–400 | Small high-ratio right-angle drives |
| 7 | 2.00 | ≤1500 | 50–400 | Heavy right-angle feeders |
| 10 | 5.50 | ≤1500 | 50–450 | Process right-angle agitators |
| 13 | 15.0 | ≤1000 | 50–500 | Heavy conveyor corners |
| 16 | 40.0 | ≤750 | 50–500 | Kiln auxiliaries right-angle |
| 19 | 100. | ≤600 | 50–500 | Large right-angle drives |
| 22 | 250. | ≤500 | 50–500 | Port machinery, heavy mill drives |
| 26 | 500. | ≤400 | 50–500 | Maximum right-angle industrial drives |
EP-B4 Horizontal Dimension Drawing — Sizes 5–12
EP-B4 Horizontal Dimension Drawing — Sizes 13–22
EP-B4 Vertical Dimension Drawing — Sizes 5–12
At sizes 19 and above, specify lubrication system requirements. Forced lubrication is strongly recommended for continuous-duty installations.
Engineering Features
Precision Spiral Bevel Input Stage
Finish-ground spiral bevel gears with individually verified tooth contact patterns provide the 90-degree direction change at 98–99% stage efficiency. Lapping after grinding ensures smooth running at all operating speeds.
Three-Stage Helical Output Train
Three helical reduction stages after the bevel deliver the full ratio range from 50:1 to 500:1. Each stage uses carburised and ground gears to DIN 5 quality, independently designed to the correct tooth load level for its position in the train.
Three Dimensional Groups (Sizes 5–26)
Frame groups 5–12, 13–22, and 23–26 use optimised housing dimensions. The 23–26 range incorporates heavy-duty bearing supports and reinforced housing walls to manage the enormous torque reaction forces at the output stage.
Forced Lubrication for Large Frames
Sizes 19–26 under continuous duty require forced lubrication. A gear-pump circuit delivers temperature-controlled, filtered oil to all four gear meshes and the bevel bearing positions, maintaining oil film thickness under all operating conditions.
Full B-Series Mounting Compatibility
Nine standard shaft/mounting configurations (BSH through BDV) are available, consistent with the B2 and B3 families. Multi-unit installations combining B4 with B2 or B3 units can use common mounting interfaces and accessories.
Engineered for 24/7 Heavy Duty
EP-B4 is not rated for intermittent or light-duty use — it is designed as a continuous-service unit for the most demanding industrial environments, with bearing L10h life calculated at 20,000+ hours under rated load at rated input speed.
Heavy Industry Applications
EP-B4 is specified for the top tier of right-angle heavy industrial drives — applications where EP-B3 has reached its torque or ratio limit:
| Industry | Application | Primary Requirement |
|---|---|---|
| Cement | Kiln right-angle auxiliary, raw mill head | 500:1 right-angle, 500 kNm |
| Mining | Right-angle thickener rake, conveyor head | High torque, 24/7, shock |
| Port Machinery | Container crane drives, stacker slew | Right-angle, very high torque |
| Steel | Cooling bed drives, right-angle roll line | Reversing, heavy shock |
| Chemical | Large polymer reactor right-angle drives | Very slow shaft, sealed, continuous |
| Power Generation | Right-angle coal handling, ash systems | High ratio, right-angle |
Full B-Series Right-Angle Gearbox Comparison
Where does EP-B4 sit in the bevel-helical family?
| Model | Bevel+Helical Stages | Ratio Range | Max Torque | Best-Fit Application Class |
|---|---|---|---|---|
| EP-B2 | 1+1 | 5–45:1 | 90 kNm | Compact right-angle, moderate ratio |
| EP-B3 | 1+2 | 25–280:1 | 200 kNm | High-ratio right-angle, heavy process |
| EP-B4 | 1+3 | 50–500:1 | 500 kNm | Maximum right-angle, ultra-heavy industry |
Choose EP-B4 when both the ratio and the torque requirements exceed EP-B3's limits simultaneously, or when the ratio requirement alone exceeds 280:1 in a right-angle layout.
Installation Planning for Large EP-B4 Units
Foundation Design. At 500 kNm continuous output torque, torque reaction forces on the mounting feet are very high. The mounting surface must be designed by a structural engineer to handle both static torque reaction and dynamic shock loads, particularly for conveyors with frequent load changes or mining applications with irregular loading.
Bevel Stage Alignment. Unlike inline helical units, the bevel stage in a B4 has two shafts at 90 degrees. Housing alignment to the driven machine and the motor must account for both horizontal and vertical plane alignment simultaneously. Use a laser alignment tool capable of right-angle shaft alignment, not a conventional parallel-shaft laser system.
Oil System Commissioning. For forced-lubrication units, commission the oil pump, filter, and cooler before first motor start. Confirm oil flow at all measurement points, set the low-flow alarm threshold, and verify oil temperature sensor operation. Do not start the gear train until the forced lubrication system is confirmed operational.
Contact our applications engineering team for installation design support, foundation load data, and commissioning checklists for large EP-B4 installations.
Frequently Asked Questions
What is the maximum output torque of EP-B4?
EP-B4 delivers a maximum nominal output torque of 500 kNm at Size 26 — the highest value in the HB bevel-helical right-angle gearbox series and equal to the four-stage helical EP-H4. This makes the B4 suitable for the largest right-angle industrial drives: cement kiln auxiliaries, heavy mining thickener rakes, port machinery slew drives, and large chemical reactor right-angle agitators.
What is the ratio range of EP-B4?
Four-stage bevel-helical ratios span approximately 50:1 to 500:1. At 500:1, a standard 1450 rpm motor produces approximately 2.9 rpm at the output shaft in a right-angle layout — without any additional speed control device. This enables very slow right-angle output drives that would otherwise require a VFD, hydraulic motor, or tandem gearbox arrangement.
When should EP-B4 be chosen over EP-B3?
Choose EP-B4 when the required ratio exceeds EP-B3's ceiling of approximately 280:1, or when both high ratio (above 200:1) and high torque (above 150 kNm) are needed simultaneously in a right-angle drive layout. Within EP-B3's coverage envelope, B3 will be shorter, lighter, and lower-cost — EP-B4 is the correct choice only where B3 is genuinely insufficient.
What industries typically specify EP-B4?
The heaviest users are cement and lime (kiln right-angle auxiliaries, large bucket elevator corners), mining (right-angle thickener rake drives, long conveyor 90-degree corners), steel (rolling mill right-angle auxiliaries, cooling bed drives), port and marine (crane slew drives, stacker-reclaimer equipment), and large chemical process plants (polymer reactor right-angle agitator drives). All share the requirement for very high right-angle torque at very low continuous output speeds.
Is forced lubrication required for EP-B4?
For sizes 5–16 at standard ambient temperatures and input speeds, splash lubrication is adequate. For sizes 19–26 under continuous duty, or for any EP-B4 unit operating above 35°C ambient or in an enclosed machine room, forced lubrication with a gear pump, oil filter, and heat exchanger is strongly recommended. The four-stage bevel-helical gear train generates more internal heat than two- or three-stage units at comparable power; forced lubrication ensures all stages — including the bevel pair at the remote end of the housing — receive adequate oil supply.
Explore the Full HB Series
Request EP-B4 Engineering Support
Four-stage bevel-helical drives require detailed application review. Share your torque, ratio, mounting orientation, ambient conditions, and duty cycle — our team provides a full sizing package including foundation loads and lubrication system specification.