Spur Gear Slew Drive Installation and Operation Guide
What is a Spur Gear Slew Drive?
A Spur Gear Slew Drive is an integrated transmission device that incorporates high-precision gears, bearings, seals, motors, and reduction mechanisms. Its core function is to convert the rotary motion of the power source into continuous, smooth 360-degree slewing motion at the output end, while withstanding significant axial loads, radial loads, and overturning moments. Simply put, it is a "rotatable joint," a key component in modern machinery for achieving large-range, heavy-load, and precise slewing functions.
Working Principle and Core Components of the Spur Gear Slew Drive
We can understand the Spur Gear Slew Drive as a highly integrated "system," rather than a single part. Its core working principle is: the power source (such as an electric motor) reduces speed and increases torque through a built-in reduction mechanism (usually a worm gear or planetary gear), then drives a large slewing bearing (a bearing with a gear ring), ultimately realizing the rotation of the equipment platform.
The main components of the Spur Gear Slew Drive include:
Slewing Bearing: This is the core component. It is essentially a rolling bearing with a gear ring. Gears (usually spur or involute teeth) are machined onto the outer or inner ring, while the other ring is fixed to the frame via mounting holes. The internal rolling elements (balls or rollers) allow smooth rotation and withstand multiple loads.
Worm Gear Type: This is the most common form. A motor-driven worm meshes with the worm gear ring on the outer ring of the slewing bearing. This structure has the advantage of reverse self-locking, meaning when the worm stops rotating, the load cannot back-drive the worm, providing a natural safety brake.
Pinion-Gear Type (Pinion and Ring Gear): A motor-driven pinion gear meshes with the gear ring of the slewing bearing. This form is more efficient and can achieve higher speeds, but usually does not have the reverse self-locking function, requiring an additional brake to maintain position.
Drive Source (Motor): Usually a hydraulic motor or electric motor, providing the original power.
Reducer: Usually integrated with the motor, used for preliminary speed reduction and torque increase before power is transmitted to the worm/pinion.
Seals: Prevent external dust and moisture from entering, and prevent internal lubricant leakage, ensuring long service life in harsh environments.
Housing: Encapsulates all components compactly into a sturdy, easy-to-install unit.
Transport, Handling, and Storage of Spur Gear Slew Drives
Transport and Handling
During transport, keep the Spur Gear Slew Drive packaging box placed in the specified orientation and avoid collisions.
When handling, wear work gloves and operate carefully.
Spur Gear Slew Drives generally have threaded holes on the outer ring; you must use 3 or more lifting eyes and lifting equipment for safe handling.
Storage
During storage, keep the Spur Gear Slew Drive packaging box placed in the specified orientation and store it in a ventilated, dry place.
In closed packaging, the product's anti-rust period is 6 months. If longer storage is required, please take special protective measures.
Installation and Maintenance of Spur Gear Slew Drives
Installation Preparation:
Check the Spur Gear Slew Drive for physical damage.
Clean the Spur Gear Slew Drive and connecting support, and remove impurities from the supporting surface (such as iron chips, burrs, paint, and welding spatter, etc.).
Cleaning Anti-rust Oil from the Mounting Surface:
Clean the external mounting surface with cleaning fluid (e.g., diesel or gasoline). The cleaning fluid must not damage the performance of the rubber seals.
Please follow the cleaning fluid usage regulations and provide staff protection.
Bolt Selection:
Lyra Drive does not recommend or supply assembly bolts. The following clauses are for reference only:
a. Please correctly select the bolt specification, type, and performance grade.
b. Bolt grade should not be lower than 8.8.
c. The bolt thread engagement length is generally 2 times the nominal bolt diameter.
d. Do not allow the bolt to protrude outside the threaded hole, otherwise it may cause interference and damage components.
e. If the allowable contact stress of the mounting surface is exceeded, please use appropriate high-strength washers.
Bolt Tightening Torque:
The following table is for reference only:
| Bolt Size | Tightening Torque (N.M) | Bolt Size | Tightening Torque (N.M) | ||||
|---|---|---|---|---|---|---|---|
| 8.8 | 10.9 | 12.9 | 8.8 | 10.9 | 12.9 | ||
| M4 | 2.25 | 3.31 | 3.87 | M16 | 168.00 | 246.00 | 288.00 |
| M5 | 4.16 | 6.77 | 7.92 | M18 | 229.00 | 336.00 | 394.00 |
| M6 | 7.80 | 11.50 | 13.40 | M20 | 327.00 | 481.00 | 562.00 |
| M8 | 19.10 | 28.00 | 32.80 | M22 | 450.00 | 661.00 | 773.00 |
| M10 | 38.00 | 55.80 | 65.30 | M24 | 565.00 | 830.00 | 972.00 |
| M12 | 66.50 | 97.70 | 114.00 | M27 | 837.00 | 1230.00 | 1439.00 |
| M14 | 107.00 | 156.00 | 183.00 | M30 | 1131.00 | 1661.00 | 1944.00 |
Installing the Spur Gear Slew Drive:
Please follow the procedure below to avoid internal stress and installation issues caused by bolt tightening.
a. Apply thread-locking adhesive to the threads.
b. Pre-tighten bolts and washers, should be tightened crosswise; refer to the figure below for the bolt tightening sequence; start from the inner or outer ring, diagonally tighten all bolts to 30% of the tightening torque, then repeat diagonal tightening to 50% of the tightening torque, and finally diagonally tighten to 100% of the tightening torque.
c. Install all bolts completely, none missing. If structural constraints prevent installing all bolts, the bolt holes must be sealed, e.g., filled with silicone, otherwise water and dust will leak into the slewing drive.
d. The thread engagement length of the mounting bolts should be considered, not too long, otherwise it will affect the rotation of the slewing bearing or cause interference.
e. After tightening the bolts, mark the bolt head and its connection point with a line. This facilitates future checks for bolt loosening.
Spur Gear Slew Drive Lubrication:
Lyra Drive products are pre-lubricated in critical areas before leaving the factory. We recommend refilling with Mobil EP2 grease. Decide whether to add additional grease during installation based on the actual situation.
a. Slewing bearing raceway: Pre-filled with grease before leaving the factory.
b. Gear and slewing bearing meshing area: Pre-filled with grease before leaving the factory.
c. Bearings supporting the gears: Pre-filled with grease before leaving the factory.
Re-lubrication Interval:
The re-lubrication interval depends mainly on the current working and environmental conditions. The exact re-lubrication interval can only be determined by testing under actual working conditions. In the absence of reference, the following table can be consulted:
| Working Conditions | Regrease Interval |
|---|---|
| Workshop, Industrial Positioners (Index Tables/Robots, etc.) | Annually |
| Harsh Field Conditions (e.g., Cranes, Wind Power Installations, Solar Installations, Aerial Work Platforms, etc.) | Annually |
| Harsh Climatic Conditions, Offshore/Desert/Polar Climates/Dirty Environments/ Continuous Weekly Operation Exceeding 70 Hours | Every 6 Months |
| Extreme Conditions (Tunnel Boring Machines, Steel Mills, Oil Fields) | Every 2 Months |
manufacturer of Spur Gear Slew Drive
Lyra Drive is a professional manufacturer specializing in the design and production of high-performance Spur Gear Slew Drives. With extensive engineering expertise and a commitment to quality, Lyra Drive provides robust, reliable, and precision-engineered slewing solutions tailored to meet the demanding requirements of various applications, including solar tracking, construction machinery, and industrial automation.
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