{"id":1975,"date":"2026-06-29T06:35:42","date_gmt":"2026-06-29T06:35:42","guid":{"rendered":"https:\/\/speed-reducer-gearbox.com\/screw-conveyor-worm-gearbox-compact-right-angle-drive-selection\/"},"modified":"2026-06-29T06:35:42","modified_gmt":"2026-06-29T06:35:42","slug":"screw-conveyor-worm-gearbox-compact-right-angle-drive-selection","status":"publish","type":"post","link":"https:\/\/speed-reducer-gearbox.com\/es\/screw-conveyor-worm-gearbox-compact-right-angle-drive-selection\/","title":{"rendered":"Screw Conveyor Worm Gearbox: Compact Right-Angle Drive Selection"},"content":{"rendered":"
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A screw conveyor is one of the most mechanically demanding applications a worm reducer can face: constant torque across the full revolution, significant radial loading from the screw’s own weight, and frequent start-under-load conditions when the trough is full. Getting the specification right at the design stage avoids the two most common field failures \u2014 overheated housings and broken output shafts.<\/p>\n

Why Screw Conveyors Demand Higher Service Factors<\/h2>\n

Unlike a belt conveyor where load varies with product flow, a screw conveyor often runs against a constant resistance set by material compaction against the trough wall. Wet bulk materials \u2014 cement slurry, animal feed pellets, mineral concentrates \u2014 can compact around a stopped screw and require two to three times the running torque to break loose on restart. That start torque lands directly on the gearbox output shaft and the first worm mesh, which is why the WP catalogue recommends a service factor of 1.5\u20131.75 for cohesive materials, rising to 2.0 for slurries with high solid content.<\/p>\n

\"Compact<\/p>\n

Right-Angle Drive: The Geometric Advantage<\/h2>\n

Most screw conveyors run the motor perpendicular to the auger axis to keep the drive assembly narrow enough to fit between the end trough and the support structure. A worm gearbox provides the 90\u00b0 shaft offset in a single stage, where a parallel-shaft reducer would need a separate bevel stage or a complex chain arrangement. The WPO and WPZ series with vertical output shaft suit vertical screw conveyors feeding hoppers from below; standard WPA or WPDA units serve the more common horizontal and slightly inclined configurations.<\/p>\n

\n
\n
<\/div>\n

WPA \u2014 Foot Mounted<\/h4>\n

Standard base-mounted unit. Suited to horizontal or inclined screws where the motor and reducer sit on a common baseplate beside the conveyor end.<\/p>\n<\/div>\n

\n
\u26a1<\/div>\n

WPDA \u2014 Motor-Flange<\/h4>\n

IEC flange on input accepts motor directly. Compact end-to-end arrangement for inline installation where space around the trough head is limited.<\/p>\n<\/div>\n

\n
\u2b06\ufe0f<\/div>\n

WPO \/ WPZ \u2014 Vertical Output<\/h4>\n

Output shaft points upward into the screw tube. Common on vertical screws discharging into overhead bins or mixing vessels.<\/p>\n<\/div>\n

\n
<\/div>\n

WPKA \u2014 Hollow Shaft<\/h4>\n

Bore slides directly over the screw shaft stub. Eliminates coupling hardware and simplifies replacement when the screw wears out.<\/p>\n<\/div>\n<\/div>\n

Sizing for Start-Under-Load Torque<\/h2>\n
\n\n\n\n\n\n\n\n\n\n
Material Type<\/th>\nRunning Factor<\/th>\nStart Factor<\/th>\nRecommended Service Factor<\/th>\n<\/tr>\n<\/thead>\n
Free-flowing grain, pellets<\/td>\n1.0<\/td>\n1.5<\/td>\n1.2<\/td>\n<\/tr>\n
Dry cement, fly ash<\/td>\n1.2<\/td>\n2.0<\/td>\n1.5<\/td>\n<\/tr>\n
Wet sand, mineral concentrate<\/td>\n1.4<\/td>\n2.5<\/td>\n1.75<\/td>\n<\/tr>\n
Animal manure slurry<\/td>\n1.5<\/td>\n3.0<\/td>\n2.0<\/td>\n<\/tr>\n
Sticky clay, adhesive paste<\/td>\n1.8<\/td>\n3.5<\/td>\n2.5<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Multiply calculated running torque by service factor to obtain gearbox selection torque.<\/p>\n<\/div>\n

\"WP<\/p>\n

Cantilever Load from the Screw Shaft<\/h2>\n

The screw shaft exerts a radial load on the gearbox output bearing every time it rotates under the weight of the auger and trapped material. For a 4-metre 200 mm diameter screw filled with wet sand at 1 900 kg\/m\u00b3 and 40% fill, the shaft weight alone can exceed 600 N at the drive end. For a WPA 100 at low speeds the cantilever limit is around 2 100 N \u2014 accommodating most horizontal screws up to 250 mm diameter. Longer or larger screws need either a steady bearing at the opposite end or a larger frame.<\/p>\n

Critical check:<\/strong> when the screw shaft connects directly to the gearbox output through a jaw coupling with no intermediate bearing, ALL radial screw weight falls on the gearbox output bearing. Always run a cantilever check \u2014 not just a torque check \u2014 before finalising the frame size.<\/div>\n

Lubrication in Dusty and Wet Environments<\/h2>\n

Screw conveyors handling dusty dry materials (flour, cement, lime) run in environments where fine particles infiltrate every seal gap. The DS split-housing series<\/a> allows inspection and re-sealing without removing the shaft connections. For pharmaceutical screw conveyors, the HSRV stainless steel worm gearbox<\/a> addresses hygiene requirements without the bulk of a helical-bevel unit. Use a synthetic polyglycol lubricant if the ambient temperature fluctuates widely \u2014 it maintains more consistent viscosity across a wider temperature range than mineral oil.<\/p>\n

\"Screw<\/p>\n

Frequently Asked Questions<\/h2>\n
\n
\n1. How do I calculate running torque for a horizontal screw conveyor?+<\/span><\/summary>\n
The standard approximation is T = C \u00d7 L \u00d7 D\u00b2 \u00d7 \u03c1 \u00d7 f \/ (2\u03c0 \u00d7 e), where C is a material coefficient (0.4\u20130.6 for cohesive, 0.05\u20130.1 for free-flowing), L is length (m), D is diameter (m), \u03c1 is bulk density (kg\/m\u00b3), f is fill fraction, and e is drive efficiency (~0.65 for worm at 1:30).<\/div>\n<\/details>\n
\n2. Can a worm gearbox survive frequent stalled screw conditions?+<\/span><\/summary>\n
Short stall durations (under 10 seconds) cause no lasting damage provided the motor trips on overcurrent before the housing overheats. Repeated long stalls \u2014 over 30 seconds \u2014 build heat faster than the housing can dissipate. Fit a shear-pin or friction clutch if stalling is a normal operating condition.<\/div>\n<\/details>\n
\n3. Is a hollow-shaft WPKA suitable for direct connection to the screw stub shaft?+<\/span><\/summary>\n
Yes, and it is the cleanest arrangement for replacement. The hollow bore must match the stub shaft diameter (typically 30\u201360 mm for mid-size screws), and a torque arm fastened to the trough end plate prevents the gearbox body from rotating.<\/div>\n<\/details>\n
\n4. What ratio gives a typical 40 rpm screw speed from a 4-pole motor?+<\/span><\/summary>\n
1440 \u00f7 40 = 36 \u2014 so a 1:40 ratio unit. In practice, 1:30 with a slightly smaller sprocket gives more flexibility to fine-tune speed; alternatively a VFD on the motor lets you hit 40 rpm from a 1:30 unit at around 1200 r\/min input.<\/div>\n<\/details>\n
\n5. How does material temperature affect gearbox selection?+<\/span><\/summary>\n
Hot material raises the ambient temperature around the drive end. For screw conveyors on dryers or hot ash systems where the trough surface reaches 60\u00b0C or above, the gearbox should be thermally isolated from the trough flange and the oil grade upgraded to VG 460 or synthetic.<\/div>\n<\/details>\n<\/div>\n
\n

Get a Sized Recommendation<\/h3>\n

Share your load data and target speed \u2014 our team at Condell Park NSW returns torque calculations and a stock check within one business day.<\/p>\n

\n
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ADDRESS<\/div>\n

27 Harley Crescent
Condell Park NSW 2200<\/div>\n

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PHONE<\/div>\n

+61 2 9708 3322<\/p><\/div>\n

\n
EMAIL<\/div>\n

sales@speed-reducer-gearbox.com<\/p><\/div>\n<\/div>\n

Send Enquiry →<\/a><\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"

A screw conveyor is one of the most mechanically demanding applications a worm reducer can face: constant torque across the full revolution, significant radial loading from the screw’s own weight, and frequent start-under-load conditions when the trough is full. Getting the specification right at the design stage avoids the two most common field failures \u2014 […]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[2903],"tags":[],"class_list":["post-1975","post","type-post","status-publish","format-standard","hentry","category-conveyor-handling"],"_links":{"self":[{"href":"https:\/\/speed-reducer-gearbox.com\/es\/wp-json\/wp\/v2\/posts\/1975","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/speed-reducer-gearbox.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/speed-reducer-gearbox.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/speed-reducer-gearbox.com\/es\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/speed-reducer-gearbox.com\/es\/wp-json\/wp\/v2\/comments?post=1975"}],"version-history":[{"count":0,"href":"https:\/\/speed-reducer-gearbox.com\/es\/wp-json\/wp\/v2\/posts\/1975\/revisions"}],"wp:attachment":[{"href":"https:\/\/speed-reducer-gearbox.com\/es\/wp-json\/wp\/v2\/media?parent=1975"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/speed-reducer-gearbox.com\/es\/wp-json\/wp\/v2\/categories?post=1975"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/speed-reducer-gearbox.com\/es\/wp-json\/wp\/v2\/tags?post=1975"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}