F Series Parallel Shaft Helical Gear Reducer

Parallel shaft helical gear reducer with IEC B5 motor input flange and solid or hollow output shaft, available in sizes F27 through F157. Motor and output shaft run in parallel planes, making the F series the preferred specification for conveyor tail-end drives, roller table drives, and any application where the motor must be positioned alongside the load shaft rather than behind it in the same axial line.

Sizes: F27 – F157
Ratios: 3.77 – 289.74
Output Torque: 120 – 15,000 N·m
Parallel Shaft Output
Efficiency: up to 98% per stage
IP55 Protection

Category: Worm Gear Reducers

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Description
Additional information

Parallel Shaft Drive

IEC B5 Motor Flange

3.77 to 289.74 Ratios

Hollow Shaft Option

IP55 Protection

ISO 9001 Certified

F Series Parallel Shaft Helical Gear Reducer Korea Ever-Power

F Series Helical Gear CNC Precision Machining

Side-by-Side Motor and Load: The Parallel Shaft Advantage

The F series parallel shaft helical gear reducer positions the motor flange on the side of the gearbox body, with the output shaft running parallel to and offset from the motor input shaft. This geometry is fundamentally different from the R series coaxial arrangement: in the F series, the motor sits alongside the gearbox rather than behind it, which reduces the total axial length of the drive assembly by approximately the length of the motor. For conveyor drives, roller table drives, and packaging machine drives where space behind the load shaft is limited, this compact axial envelope is a decisive mechanical advantage.

The helical gear stages in the F series achieve efficiency of up to 98% per stage, identical to the R series, because both product lines share the same gear tooth geometry and material specifications: 20CrMnTi case-hardened alloy steel, profile-ground to ISO 1328 Grade 6 accuracy after heat treatment. A two-stage F series gearbox achieves approximately 96% overall efficiency; a three-stage unit approximately 94%. These values are consistent regardless of the parallel-shaft geometry, because the gear mesh characteristics are determined by tooth form and material, not by the relative position of input and output shafts.

The hollow shaft (shrink disc) output option, available on F37 and above, allows the F series to mount directly on the load shaft of a roller, drum, or sprocket without a separate coupling, eliminating shaft alignment requirements and further reducing the drive assembly length to the minimum possible for the given ratio and output torque.

Explore the matched motor range at Three-Phase Induction Motors, or browse the complete gearbox family at Helical Gear Reducers.

F Series Size and Performance Data

Performance data at rated input speed 1440 rpm (4-pole motor). 2-stage and 3-stage configurations available per size. Output torque values shown are maximum for each housing size.

Size	Stages	Ratio Range	Max Output Torque (N·m)	Efficiency (%)	IEC Motor Frames	Max Input kW	Weight (kg)
F27	2	3.77 – 24.35	120	96	71, 80, 90	1.5	5.0
F37	2	3.77 – 24.35	200	96	80, 90, 100	2.2	8.5
F47	2 / 3	3.77 – 289.74	350	94 – 96	90, 100, 112	4.0	14.0
F57	2 / 3	3.77 – 289.74	550	94 – 96	100, 112, 132	5.5	21.0
F67	2 / 3	3.77 – 289.74	900	94 – 96	112, 132, 160	9.2	30.0
F77	2 / 3	5.21 – 289.74	1,500	94 – 96	132, 160, 180	15	50.0
F87	2 / 3	5.21 – 289.74	2,400	94 – 96	160, 180, 200	30	72.0
F97	2 / 3	5.21 – 289.74	3,800	94 – 96	180, 200, 225	45	105.0
F107	2 / 3	5.21 – 289.74	6,000	94 – 96	200, 225, 250	75	155.0
F127	2 / 3	5.21 – 289.74	9,000	94 – 96	225, 250, 280	110	230.0
F157	2 / 3	5.21 – 289.74	15,000	94 – 96	250, 280, 315	160	360.0

Gearbox Specifications

Gear material	20CrMnTi case-hardened
Tooth accuracy	ISO 1328 Grade 6
Housing material	GJL-250 cast iron
Gear oil	ISO VG 220 synthetic
Protection	IP55
Thermal limit	100 °C oil temperature
Paint finish	RAL 5010 blue epoxy
Mounting	Any orientation

Input and Output Configurations

Input type	IEC B5 flange direct
Shaft arrangement	Parallel offset
Output shaft	Solid keyed (standard)
Hollow shaft	Shrink disc (F37 up)
Output flange	Available F47 and above
Torque arm	Included with hollow shaft
IEC frame range	71 – 315
Standards	ISO 9001 / CE

Typical Applications for F Series Parallel Shaft Helical Reducers

F Series Helical Reducer Roller Table Conveyor Application

Roller Table Drives

Steel mill and rolling mill roller tables use F series parallel shaft reducers with hollow shaft output mounted directly on each roller shaft. The parallel offset geometry positions the motor beside the roller rather than behind it, fitting within the narrow centre-to-centre roller spacing of hot and cold rolling lines without interference between adjacent drive units.

F Series Helical Reducer Food Conveyor Application

Accumulation Conveyors

Live roller accumulation conveyors in warehouse sortation systems and distribution centres use F series reducers with hollow shaft output at each driven roller zone. The compact parallel shaft arrangement keeps the drive unit within the conveyor frame width and minimises the floor space occupied by the accumulated drive motor and gearbox assembly per roller zone.

F Series Helical Reducer Heavy Duty Application

Heavy Industrial Mixers

Top-entry agitators on large industrial tanks where available headroom above the vessel nozzle is restricted use F series reducers. The parallel shaft geometry reduces the vertical height of the motor-gearbox assembly compared to a coaxial inline arrangement, because the motor flange is offset sideways rather than adding to the vertical stack height above the gearbox.

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Drum and Pulley Drives

Conveyor head pulley and tail pulley drives in bulk material handling plants use F series hollow shaft reducers mounted directly on the pulley shaft stub end, eliminating the separate coupling and pillow block bearing arrangement that would otherwise be needed when using a solid shaft reducer with an outboard pulley bearing.

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Packaging Machine Drives

Cartoning, wrapping, and palletising machines use F series reducers for the main infeed and discharge conveyor drives, where the compact parallel shaft package allows the motor and gearbox to be mounted within the machine frame envelope without the motor protruding beyond the machine footprint.

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Pump and Fan Parallel Drives

Pump skid arrangements where two pumps must be driven from a single motor through a parallel offset gearbox use F series reducers. The parallel shaft arrangement allows the motor centre height to match the pump shaft centre height without an adapter plate, simplifying skid base fabrication and pipework alignment.

F Series vs R Series: Choosing Between Parallel and Inline Shaft

Axial Length vs Lateral Width

The R series (inline) has the shortest lateral width but the longest axial length, because the motor mounts behind the gearbox and both motor and gearbox lengths add together in the axial direction. The F series (parallel shaft) has a larger lateral width because the motor flange is on the side of the gearbox body, but the total axial length is only the gearbox length, as the motor does not add to axial projection. For conveyor drives where axial space behind the head pulley is limited (wall-mounted drives, tail-end drives on enclosed tunnel conveyors), the F series is the standard choice regardless of efficiency equivalence with the R series.

Hollow Shaft on Driven Equipment

Both R and F series offer hollow shaft output via shrink disc. The practical difference is that the R series hollow shaft is coaxial with the motor, so the motor must be positioned at the end of the driven shaft with a torque arm reacting the motor weight. The F series hollow shaft has the motor offset to the side, which means the motor weight is supported partially by the gearbox body and partially by the torque arm, reducing the bending moment on the driven shaft compared to the coaxial arrangement. For applications where the driven shaft is long and slender (screw conveyors, agitator shafts), the F series hollow shaft produces less shaft deflection at the gearbox mounting point.

Centre Height Matching

The F series parallel shaft arrangement allows the output shaft centre height to be matched to standard IEC motor shaft centre heights or standard pump shaft centre heights by selecting the appropriate gearbox size and motor frame combination. This is particularly useful in retrofit situations where an existing motor and gearbox must be replaced with a motor-gearbox unit that matches the shaft centre height of the existing installation without modifying the machine base or foundation. Korea Ever-Power can provide centre height dimension drawings for any F series size and motor frame combination to verify dimensional compatibility before ordering.

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CE and ISO Certifications

Frequently Asked Questions — F Series Parallel Shaft Helical Reducer

Can the motor be mounted on the left or right side of the F series gearbox?

Yes. The F series gearbox input flange is available on both the left-hand and right-hand face of the gearbox body relative to the output shaft direction. The standard designation is F (right-hand motor position) or FZ (left-hand motor position), viewed from the output shaft end looking toward the gearbox. The output shaft rotation direction is the same for both configurations with the same gear ratio, but the motor position relative to the output shaft is mirrored. Both left-hand and right-hand configurations are available as standard products. Specify the required motor position when ordering by providing the mounting position diagram number per the Korea Ever-Power dimensional catalogue.

What is the shaft offset between motor centreline and output shaft centreline?

The shaft offset (distance between the parallel motor input shaft centreline and the output shaft centreline) increases with gearbox size and ratio. For F27, the offset is approximately 55 to 90 mm depending on ratio. For F97, the offset is approximately 180 to 280 mm. This offset dimension determines the minimum clear space required beside the output shaft for the motor to fit without obstruction. Korea Ever-Power provides the offset dimension for each size and ratio combination in the dimensional drawing supplied with the order. For retrofit applications where the shaft offset must match an existing installation, provide the required offset dimension in the enquiry and Korea Ever-Power will verify which size and ratio combination achieves the required centre distance.

Is the F series interchangeable with other brands of parallel shaft helical reducers?

The Korea Ever-Power F series follows the same dimensional standard as the majority of IEC-frame parallel shaft helical gearboxes in this size range. Key dimensions including IEC B5 motor flange diameter and pilot bore, output shaft diameter and keyway, foot mounting bolt pattern, and overall housing outline are designed to match or closely approximate the dimensional standards of the most common European and international parallel shaft helical gearbox series. In most cases, the Korea Ever-Power F series can be used as a dimensional equivalent replacement for gearboxes from other manufacturers of the same size designation. A dimensional drawing should be compared to verify interchangeability for critical retrofit applications before ordering.

How does the F series handle high radial loads from belt and chain drives?

The F series output shaft is supported by taper roller bearings (sizes F47 and above) that provide higher radial load capacity than the ball bearings used in worm gearboxes of similar frame size. Permissible radial loads at the shaft midpoint range from approximately 2,500 N for F37 to over 35,000 N for F157. For belt or chain drive applications where significant radial force is applied to the output shaft, the radial load must be calculated from the belt tension and confirmed against the permissible value for the gearbox size and shaft extension length used. Korea Ever-Power application engineers can assist with belt drive radial load calculations on request.

Can the F series be supplied with a backstop to prevent reverse rotation?

Yes. A mechanical backstop (sprag clutch type) can be factory-fitted on the F series gearbox input shaft for sizes F47 and above. The backstop allows rotation in one direction only and locks instantaneously when the shaft attempts to reverse. This is used in inclined conveyor applications to prevent the loaded belt from running back when the motor stops or trips, without the need for an electromagnetic brake. The backstop must be specified for the input shaft rotation direction (clockwise or counterclockwise viewed from the motor end) at time of order. The backstop does not add significant length to the gearbox and is enclosed within a modified end cover that maintains the IP55 rating of the standard gearbox.

Request a Quote for F Series Parallel Shaft Helical Reducers

Specify size, ratio, motor position (left or right), output shaft type, mounting orientation, and motor frame. Learn about our factory on the About Us page.

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Edited by Cxm

Additional information

Editor	Cxm