Description

S Series Helical-Worm Gearbox & Geared Motor

Compact Right-Angle Drive with Helical + Worm Transmission

KB Transmission Star S Series Helical-Worm Gearboxes combine a high-efficiency helical pre-stage with a worm gear stage to provide compact right-angle power transmission, broad reduction ratios, smooth running characteristics and flexible mounting options.

Available in S37, S47, S57, S67, S77, S87 and S97 frame sizes, the series covers applications from compact conveying equipment to higher-torque industrial machinery.

Multiple output and mounting configurations are available, including solid shaft, hollow shaft, B5 flange, B14 flange and shrink-disc arrangements.

Key Technical Range

0.12–22 kW Motor Power
6.80–288.00 Standard Ratio Range
Up to 4,000 Nm Output Torque
S37–S97 Frame Sizes
M1–M6 Mounting Positions

Need Help Selecting an S Series Gearbox?

Send us your:

Motor Power + Input Speed + Required Output Speed + Torque + Mounting + Application

[REQUEST AN ENGINEERING QUOTE]

[SEND YOUR APPLICATION DATA]

Not sure which model you need? Send us your application and operating conditions. Our engineering team can help determine the appropriate S Series size, ratio, output configuration and motor.

S Series at a Glance

The published performance tables cover numerous motor-power, output-speed, ratio, torque and service-factor combinations across the series rather than one universal rating for every frame size.

What Is an S Series Helical-Worm Gearbox?

A conventional worm gearbox transmits power directly from a worm shaft to a worm wheel.

The S Series uses an additional helical reduction stage before the worm stage.

Standard Worm Gearbox

Motor
  ↓
Worm
  ↓
Worm Wheel
  ↓
90° Output

S Series Helical-Worm Gearbox

Motor
  ↓
Helical Gear Stage
  ↓
Worm Gear Stage
  ↓
90° Output

This combination allows the gearbox to achieve substantial speed reduction in a compact right-angle arrangement while retaining the smooth running characteristics associated with worm gearing.

The original catalog specifically describes the series as a helical-worm geared motor and provides seven principal gearbox sizes.

Why Choose an S Series Helical-Worm Gearbox?

Compact Right-Angle Transmission

The S Series changes the direction of power transmission by 90°, making it suitable for machines where the motor and driven shaft cannot be arranged inline.

Its compact architecture helps reduce overall machine space requirements.

Helical Pre-Stage + Worm Final Stage

The helical pre-stage provides an additional speed reduction before torque enters the worm stage.

This architecture gives designers greater ratio flexibility than a simple single-stage worm gearbox while maintaining a compact right-angle configuration.

Broad Reduction Ratio Coverage

Depending on frame size, standard S Series configurations cover reduction ratios from approximately:

6.80:1 to 288.00:1

Higher total ratios are available through selected multi-stage combinations, but these are treated separately from the standard S Series range.

Smooth & Quiet Operation

Progressive helical tooth engagement combined with the smooth meshing characteristics of the worm stage helps provide stable torque transmission and low-noise operation.

This makes the S Series suitable for conveyors, production machinery and other equipment operating for extended periods.

Multiple Output Configurations

The S Series is available with:

• Solid output shaft
• Hollow shaft
• Hollow shaft with flange
• Shrink-disc hollow shaft
• B5 flange
• B14 flange

This gives OEM engineers greater freedom when integrating the gearbox into different machine layouts.

S37–S97 Verified Technical Selection Guide

The following values are mapped from the original TS38–TS98 catalog performance data into the website S37–S97 naming system.

Important Engineering Note

The values above represent each frame size’s available catalog envelope.

They do not mean every motor power can be combined with every ratio or that every ratio can produce the maximum listed torque.

Final selection must consider:

Motor Power · Input Speed · Required Output Speed · Actual Output Torque · Service Factor · Radial Load · Mounting Position

The Performance Parameter portion of the source catalog provides those parameters as linked selection points rather than independent values.

S Series Critical Dimensions for Installation & Replacement

For replacement projects, gearbox ratio alone is not sufficient.

Critical mechanical dimensions should also be confirmed.

Solid-Shaft Critical Dimensions

Replacement Check

Before replacing an existing gearbox, confirm:

• Output shaft diameter
• Shaft extension
• Key size
• Foot mounting pattern
• Flange dimensions
• Hollow bore, if applicable
• Motor interface
• Output center position
• Installation orientation

Never assume dimensional interchangeability from the frame number alone.

[SEND YOUR EXISTING GEARBOX DRAWING →]

S Series Mounting & Output Configurations

The S Series provides multiple mechanical configurations for different machine designs.

S Series

Foot-Mounted, Solid Output Shaft

A conventional foot-mounted right-angle gearbox for base-mounted machinery.

Suitable for:

• conveyors
• processing equipment
• production machinery
• material handling systems

SF Series

B5 Flange-Mounted, Solid Output Shaft

Designed for direct flange installation where the gearbox is attached to the driven machine rather than mounted on a separate base.

SA Series

Hollow-Shaft Gearbox

Allows the gearbox to mount directly over the machine shaft, helping reduce couplings, external shaft connections and installation length.

SAF Series

Hollow Shaft with B5 Flange

Combines hollow-shaft mounting with a large B5 flange for secure direct machine integration.

SAZ Series

Hollow Shaft with B14 Flange

Provides a compact alternative flange arrangement for OEM machinery.

SH Series

Hollow Shaft with Shrink Disc

Provides a keyless friction connection between the gearbox hollow shaft and the driven machine shaft.

Suitable where secure shaft clamping and simplified removal are required.

SHF / SHZ Series

Shrink Disc with Flange Mounting

Combines shrink-disc output with B5 or B14 flange arrangements for more specialized machine layouts.

The catalog illustrates these multiple solid-shaft, hollow-shaft, flange and shrink-disc variants as distinct configurations.

Available Hollow-Shaft Configurations

Depending on frame size and configuration, multiple hollow-bore options may be available.

The dimensional drawings use H7 bore tolerances for hollow-shaft interfaces.

For replacement projects, always confirm:

Bore Diameter + H7 Tolerance + Keyway + Hollow-Shaft Length

rather than selecting only from the gearbox frame size.

Need a Hollow-Shaft Dimension?

Send us:

Model + Required Bore + Existing Shaft Diameter + Mounting Configuration

[REQUEST SA / SAF DIMENSIONS]

Standard S Series vs. Multi-Stage Combination

This distinction is important when selecting very high ratios.

Standard S Series

A standard S37–S97 unit consists of:

Helical Stage + Worm Stage

with standard ratios up to approximately 288:1, depending on frame size.

Multi-Stage Combination

For applications requiring extremely low output speed, selected S Series gearboxes can be combined with an additional reduction stage.

These combinations can achieve much larger total ratios.

Important

Do not select a standard S Series frame from a multi-stage ratio alone.

Contact engineering when:

• Required ratio exceeds the standard range
• Output speed is extremely low
• Starting torque is high
• Continuous operation is required
• Load inertia is significant

[ASK ABOUT HIGH-RATIO COMBINATIONS →]

Typical Applications

Conveyor Systems

S Series helical-worm geared motors are well suited to belt conveyors, roller conveyors and transfer systems requiring compact right-angle installation.

Material Handling

Suitable for industrial logistics, warehouse equipment, transfer systems and material movement machinery.

Packaging Machinery

The compact 90° drive arrangement allows the gearbox to be integrated into automated packaging, filling, labeling and conveying equipment.

Mixers & Processing Equipment

Higher-torque frames can be selected for mixing, processing and other equipment requiring low-speed right-angle output.

Food Processing Equipment

Suitable for conveyors and processing machinery where compact installation and stable operating speed are required.

OEM Industrial Machinery

Multiple output-shaft and mounting configurations make the S Series particularly useful for machinery manufacturers requiring flexible gearbox integration.

How to Select an S Series Helical-Worm Gearbox

A correct gearbox selection should not be based on ratio alone.

Step 1 — Motor Power

Provide:

kW or HP

Example:

2.2 kW

Step 2 — Input Speed

Typical motor input speeds may include:

1400 / 1450 / 1750 rpm

depending on motor poles and operating frequency.

Step 3 — Required Output Speed

Approximate ratio:

i = Input Speed ÷ Output Speed

Example:

1400 ÷ 35 = approximately 40:1

Step 4 — Required Output Torque

The gearbox must provide sufficient permissible torque under actual operating conditions.

Do not assume the frame’s maximum catalog torque is available at every motor/ratio combination.

Step 5 — Service Factor

Consider:

• operating hours per day
• starts per hour
• load classification
• shock loading
• machine inertia
• ambient conditions

The catalog includes service factor, load classification and mass acceleration factor as part of the selection process.

Step 6 — Radial & Axial Loads

External loads must be checked when the output shaft directly carries:

• sprockets
• pulleys
• belt drives
• chain drives

The source catalog provides radial-load calculation methodology specifically for this reason.

Step 7 — Output Configuration

Select:

S / SF / SA / SAF / SAZ / SH / SHF / SHZ

according to how the gearbox connects to the machine.

Step 8 — Mounting Position

Confirm:

M1 / M2 / M3 / M4 / M5 / M6

Mounting position affects lubrication requirements and oil fill quantity.

Not Sure Which S Series Gearbox You Need?

You do not need to determine the complete model number yourself.

Send us:

Application: Belt Conveyor
Motor Power: 2.2 kW
Input Speed: 1450 rpm
Required Output Speed: 30 rpm
Mounting: Hollow Shaft
Operating Time: 16 hours/day
Quantity: 10 pcs

Our engineering team can evaluate:

Frame Size → Ratio → Output Torque → Service Factor → Output Configuration → Motor → Mounting Position

[SEND YOUR APPLICATION DATA]

Mounting Positions M1–M6

S Series gearboxes can be configured for different installation positions.

Correct mounting-position specification is important because it determines:

• Lubricant quantity
• Oil level
• Breather position
• Drain position
• Internal lubrication conditions

Engineering Note

For selected flange, hollow-shaft and shrink-disc configurations, mounting position and high input speed can increase lubricant churning losses.

Applications operating above approximately 2500 rpm input speed should therefore be confirmed with our engineering team.

When Requesting a Quote

Please specify:

M1 / M2 / M3 / M4 / M5 / M6

or send us an installation photo if you are unsure.

Lubrication for Reliable Operation

S Series helical-worm gearboxes use oil lubrication.

Mineral and synthetic gear oils can be selected according to:

• ambient temperature
• operating temperature
• gearbox size
• load
• mounting position
• application conditions

Oil Quantity Is Configuration-Dependent

The required lubricant quantity changes according to:

Frame Size + Mounting Position + Ratio + Gear Configuration

Therefore, S37–S97 should not be assigned one fixed oil capacity per frame size without identifying the exact mounting arrangement.

Important

Do not mix mineral and synthetic gear oils.

For lubricant recommendation, send us:

Gearbox Model + Ratio + Mounting Position + Ambient Temperature

Recommended Maintenance

A defined maintenance program helps maintain gearbox reliability and seal performance.

Initial Oil Change

Approximately:

300 operating hours

after initial commissioning.

Routine Inspection

Approximately every:

3,000 operating hours

or at least:

every 6 months

Check:

• lubricant condition
• oil level
• seals
• signs of leakage
• abnormal noise
• unusual temperature

Long-Term Maintenance

Depending on operating conditions, inspect and replace lubricant, bearing grease and sealing components as required.

High operating temperatures or demanding duty can shorten maintenance intervals.

Replacing an Existing Helical-Worm Gearbox?

If you already have an S Series, helical-worm or right-angle gearbox installed, send us the existing gearbox information.

Please Provide

Existing Brand
Model Number
Nameplate Photo
Motor Power
Gear Ratio / Output Speed
Output Shaft or Hollow Bore
Foot / Flange Dimensions
Mounting Position
Installation Photo

Our engineering team can evaluate an appropriate KB Transmission Star S Series configuration.

Dimensional and performance interchangeability must be verified before replacement.

[REQUEST A CROSS-REFERENCE]

S Series vs. Standard Worm Gearbox

Which One Should You Choose?

Choose S Series when you need:

Helical-worm architecture + multiple mounting options + right-angle output + flexible hollow-shaft configurations

Choose a standard worm gearbox when:

simplicity, compact size and general-purpose speed reduction are the primary requirements.

For OEM Machinery Manufacturers

Developing a new machine?

Our engineering team can support selection according to:

• motor power
• input speed
• required output speed
• torque
• service factor
• mounting position
• output-shaft arrangement
• available installation space

For OEM projects, send machine drawings or drive-system requirements before final gearbox selection.

[START AN OEM PROJECT]

Why Work With KB Transmission Star?

Industrial Transmission Focus

KB Transmission Star focuses on industrial gearboxes and geared motors for OEM manufacturers, distributors and industrial users.

Engineering Selection Support

We evaluate:

Power · RPM · Ratio · Torque · Service Factor · Radial Load · Output Configuration · Mounting Position

instead of selecting a gearbox from ratio alone.

Multiple Gearbox Technologies

Our product portfolio includes:

• S Series Helical-Worm
• R Series Helical
• K Series Helical-Bevel
• F Series Parallel-Shaft Helical
• KKM Helical-Hypoid
• NMRV Worm Gear Reducers
• Double Reduction Gearboxes

This allows the drive architecture to be selected according to the application.

OEM & Distributor Support

Available support can include:

• Motor combinations
• Technical drawings
• Application selection
• OEM configurations
• Private labeling
• Export packaging
• Repeat-order supply

S Series Helical-Worm Gearbox FAQ

What is an S Series helical-worm gearbox?

An S Series gearbox combines a helical reduction stage with a worm gear stage to provide compact right-angle speed reduction. It is available in multiple frame sizes, ratios, output-shaft arrangements and mounting configurations.

What sizes are available?

The website range includes:

S37, S47, S57, S67, S77, S87 and S97.

What is the power range?

The complete S Series covers approximately:

0.12–22 kW

depending on gearbox size, ratio and motor combination.

What is the maximum S Series ratio?

Standard configurations reach approximately:

288:1

depending on frame size.

Selected multi-stage combinations can achieve higher overall ratios.

What is the maximum output torque?

The largest standard frame in this range, S97, has a catalog maximum output torque of approximately:

4,000 Nm

Actual permissible torque depends on ratio, motor power and application conditions.

What is the difference between S Series and a standard worm gearbox?

S Series uses:

Helical Stage + Worm Stage

while a conventional worm gearbox primarily uses:

Worm + Worm Wheel

The additional helical stage provides another reduction stage within the drive system.

Is a hollow-shaft version available?

Yes. SA, SAF, SAZ and SH configurations provide hollow-shaft options for different mounting requirements.

Is a shrink-disc version available?

Yes. Selected SH, SHF and SHZ configurations use a shrink-disc output arrangement.

Which mounting positions are available?

S Series gearboxes can be configured in:

M1–M6

mounting positions.

Does mounting position affect lubrication?

Yes. Mounting position affects oil quantity, oil level and the position of lubricant service components.

Can you help replace another gearbox brand?

Yes. Send the existing model, nameplate, motor data and critical installation dimensions. We can evaluate an appropriate S Series configuration.

What information is required for a quote?

Please provide:

Application, motor power, input speed, required output speed or ratio, torque if known, output arrangement, mounting position and quantity.

Request an S Series Gearbox Quote

Get an Engineering-Based Recommendation

Correct gearbox selection affects:

Operating Life · Temperature · Torque Capacity · Bearing Load · Reliability · Maintenance · Machine Uptime

Send us:

✓ Application
✓ Motor Power
✓ Input Speed
✓ Required Output Speed
✓ Required Ratio
✓ Required Torque
✓ Output Shaft / Hollow Bore
✓ Mounting Type
✓ Mounting Position
✓ Operating Hours
✓ Quantity
✓ Existing Gearbox Model, if replacing

[REQUEST ENGINEERING QUOTE]

Engineering selection support available for OEMs, distributors and industrial replacement projects.