Product Overview — EP-S37 Helical-Worm Gear Reducer
When space is at a premium and noise must be minimised, the EP-S37 helical-worm gear reducer delivers where conventional worm reducers fall short. A single helical input stage cascades into a precision worm wheel set, combining the efficiency of helical gearing with the high reduction ratio of a worm — all within a right-angle housing compact enough to fit inside machine frames that rule out parallel-shaft drives. Power ratings from 0.12–1.5 kW, peak output torque up to 150 N·m, and ratios spanning 8.74–196.11 cover the full range of light industrial and precision machine drive requirements.
The helical first stage is the key differentiator. By pre-reducing speed before it reaches the worm mesh, it reduces worm tooth sliding velocity — the primary source of worm-gear heat and noise — at any given overall ratio. The result is a drive that runs 6–10 dB(A) quieter than a worm-only reducer of equivalent frame size under identical load, while achieving 75–80% overall transmission efficiency rather than the 55–65% typical of single-stage worm units.
All internal components are housed in a rigid cast-iron body machined on a single datum, preserving gear and bearing alignment over the full service life. Five structural types — S, SF, SA, SAF, SAT — plus the SA-SZ input-shaft variant cover virtually every machine interface, eliminating the need for custom engineering in the great majority of applications. Explore the full Ever Power gear reducer range on our product homepage.
Technical Specifications — EP-S37
| Parameter | Specification |
|---|---|
| Gear Type | Helical pre-stage + worm gear set (right-angle output) |
| Number of Stages | 2 (1 helical + 1 worm) |
| Motor Power Range | 0.12–1.5 kW |
| Max Output Torque | 150 N·m |
| Gear Ratio Range | 8.74–196.11 |
| Output Speed Range | 7–161 rpm |
| Approximate Unit Weight | 6–10 kg |
| Max Output Radial Load | 2,400 N |
| Overall Efficiency | 75–82% (vs 55–65% for equivalent single-stage worm) |
| Lubrication | Oil bath; ISO VG 220 synthetic-blend worm gear oil (factory fill) |
| Housing Material | Close-grained cast iron (HT250) |
| Worm Shaft Material | 20CrMnTi alloy steel, case-hardened HRC 58–62, profile ground Ra ≤ 0.4 µm |
| Worm Wheel Material | Centrifugally cast phosphor-bronze (ZCuSn10P1) |
| Helical Stage Material | 20CrMnTi alloy steel, case-hardened, precision ground DIN 6 |
| Protection Rating | IP55 standard; IP65 optional |
| Ambient Temperature | −25 °C to +40 °C (standard lubricant) |
| Noise Level | ≤ 68 dB(A) at rated load (1 m, free-field) |
| Standards Compliance | ISO 14521 worm gear rating; ISO 281 bearing life; CE Machinery Directive |
Structural Types & Mounting Configurations — S37 Series
The S37 series is produced in five structural types plus an input-shaft-only SA-SZ variant. All share the same internal helical-worm gear train and achieve identical output torque and efficiency ratings. The structural type determines the mounting method and driven-machine interface.
| Type Code | Description |
|---|---|
| S37 | foot-mounted, solid output shaft |
| SF37 | B5 flange-mounted, solid output shaft |
| SA37 | shaft-mounted, hollow output bore |
| SAF37 | B5 flange + hollow output bore |
| SAT37 | torque-arm, hollow output bore |
SF and SAF Mounting Positions
Flange-mounted SF37 and SAF37 variants support all six standard mounting positions. Oil fill level and breather plug position must be adjusted per mounting position — refer to the position-specific lubrication table in the installation manual.
SA and SAT Torque-Arm Mounting Positions
The SA37 shaft-mounted and SAT37 torque-arm variants mount directly onto the driven shaft, reacting torque through the torque arm rather than a baseplate. This eliminates shaft-to-shaft coupling alignment and is particularly suited to conveyor head drives and drum agitators.
Key Advantages of the EP-S37 Helical-Worm Reducer
The helical input stage of the EP-S37 achieves ≥98% per-stage efficiency, contributing directly to the 75–82% overall efficiency of the complete unit — 15–25 percentage points above conventional single-stage worm reducers. In continuous-duty applications this margin translates to measurable energy cost reduction and lower operating heat, reducing cooling requirements and extending lubricant life.
The S-series right-angle configuration delivers 150 N·m from a housing sized for 0.12–1.5 kW — a torque density comparable to much larger parallel-shaft units. The perpendicular input-to-output layout is inherently suited to machine geometries where the motor and driven shaft cannot share the same axis, eliminating additional bevel stages or chain-and-sprocket drives that add cost and maintenance.
By pre-reducing speed in the helical stage before it reaches the worm mesh, the EP-S37 reduces worm sliding velocity at any given overall ratio. Lower sliding velocity directly reduces worm-mesh friction noise, yielding typical noise levels 6–10 dB(A) below equivalent single-stage worm reducers — an advantage valued in food production halls, pharmaceutical facilities, and any environment with operator occupancy near the drive.
Ratios from 8.74 to 196.11 in a single housing are achievable with the EP-S37, covering applications from moderately fast conveyor drives at the lower end to very slow-rotation stirring and positioning drives at the upper end. This breadth eliminates the need to cascade multiple reducers in most applications, simplifying the drivetrain and reducing total installation length.
Five structural types — S, SF, SA, SAF, SAT — plus the SA-SZ input shaft variant address every practical machine interface without custom engineering. SA and SAF hollow-bore types allow direct shaft mounting, eliminating flexible couplings and their associated alignment requirements. The SAT torque-arm type simplifies drum and conveyor installations further by reacting torque through a single rubber-buffered arm rather than a rigid baseplate.
The EP-S37 worm wheel is manufactured from centrifugally cast phosphor-bronze (ZCuSn10P1), chosen for its combination of high load capacity, low friction against hardened steel, and resistance to adhesive wear under boundary-lubrication conditions during start-up. The hardened and profile-ground worm shaft (Ra ≤ 0.4 µm) maintains an elastohydrodynamic oil film across the full operating speed range, extending tooth-surface life to typically 25,000–40,000 hours.
Structural Type Diagrams — S37 Series
Use the diagrams below to confirm the external geometry, mounting interface, and connection dimensions of each S37 structural type before finalising your machine design. Certified dimensional drawings in DXF and PDF are available on request.
S37 Foot-Mount, Solid Output Shaft
SF37 B5 Flange, Solid Output Shaft
SA37 Shaft-Mounted, Hollow Bore
SAF37 B5 Flange + Hollow Bore
SAT37 Torque-Arm, Hollow Bore
SA37-SZ Input Shaft Only
Industry Applications — Where the EP-S37 Excels
| Industry Sector | Typical Application |
|---|---|
| Sewing machine tables, yarn tensioners, and fabric spreader rolls requiring whisper-quiet, compact right-angle drives with high reduction in a tiny footprint. | |
| Light Automation | Label dispensers, small conveyor diverters, and weighing-line reject chutes where low noise and shock-tolerance are both mandatory. |
| Medical Devices | Rehabilitation exercise machines and sample-transfer racks in lab automation systems, where vibration must be kept below clinically acceptable thresholds. |
| Retail Display | Rotating merchandise stands, motorised shop-window mannequins, and interactive kiosk turntables needing silent, low-speed drive. |
Application Case Study: Yarn Winding in a Polyester Fibre Plant
A synthetic fibre mill required a drive for 48 individual yarn-winding heads that would fit within a 160 mm × 160 mm space envelope. An EP-S37 with a 0.18 kW motor and 96.5:1 ratio achieved 14.8 rpm output with noise measured at 51 dB(A) — below the plant's occupational noise threshold — and the compact footprint allowed winding head spacing to be reduced by 40 mm, enabling a 6% wider machine with the same floor length.
Model Designation Guide — How to Order an EP-S37
Every element of the S-series order code defines a specific product attribute. The example below shows a 1.5 kW, torque-arm, hollow-bore unit in mounting position M1:
EP – S37 – SAT – Y – 2 – 1.5 – 4P – M1
| Code Element | Meaning |
|---|---|
| EP | Brand identifier — Ever Power |
| S37 | Series and frame size — S-series helical-worm |
| SAT | Structural type: torque-arm, hollow-bore output |
| Y | Motor type: Y-series IEC standard induction motor |
| 2 | Number of gear stages (helical + worm) |
| 1.5 | Motor rated power in kW |
| 4P | Motor pole count (1,450 rpm at 50 Hz) |
| M1 | Mounting position (1 of 6 standard positions) |
Frequently Asked Questions — EP-S37
What makes the EP-S37 quieter than a conventional worm reducer?
The EP-S37 places a single helical gear stage before the worm wheel set. The helical stage — which operates at nearly 98% efficiency — absorbs the bulk of the speed reduction with minimal noise, leaving the worm stage to handle only the final portion of the ratio at low peripheral velocity. This architecture typically reduces operating noise by 6–10 dB(A) compared with a worm-only reducer of equal ratio.
What is the smallest motor that can be fitted to the EP-S37?
The EP-S37 accepts IEC frame 56 motors (0.06 kW, 4P) as the smallest standard fit. For even smaller drives, specify the B14 face-mount option, which suits IEC 56 motors with a 9 mm shaft. Confirm that the combined motor-gearbox thermal rating suits the duty cycle before ordering.
Can the EP-S37 be used with a permanent-magnet DC motor?
Yes, provided the motor's IEC or NEMA frame matches the gearbox input flange. DC motors running at variable speeds should stay above 20% of rated speed to avoid bearing thermal stress. For speeds below this, specify the forced-ventilation motor option.
What are the MOQ and lead-time requirements for the EP-S37?
Minimum order value is USD 1,500; mixed orders across the S-series or other EP product lines are welcome. Sample quantities of 1–5 units are available for new customers. Standard EP-S37 units ship in 10–25 working days; custom configurations (non-catalogue ratios, special shaft diameters, or surface treatments) require 20–45 working days. Trade terms: EXW, FOB, CIF, and DAP as standard; FCA, CPT, CIP, and DDP negotiable.
How is the EP-S37 lubricated, and how often should the oil be changed?
The EP-S37 is factory-filled with ISO VG 220 synthetic-blend worm gear oil, optimised for the combined helical-worm contact regime. First change is due at 400 operating hours; subsequent intervals are every 5,000 hours or 24 months, whichever comes first. The combination of a pre-stage helical gear and the worm set means the total oil volume is used more efficiently than in a pure worm reducer — thermal cycling is reduced and the oil retains its viscosity index longer.
Discover the Right Compact Drive for Your Machine
The EP-S37 is one of seven models in the Ever Power S-series helical-worm range, covering torque requirements from 150 N·m to 3,500 N·m. Whether you are designing a new machine or upgrading an existing drive, our engineering team provides free application reviews and selection support. Learn about Ever Power and request a no-obligation quotation.