BEYOND THE PLANETARY

ATLANTA has fundamentally redesigned the traditional worm gear and transformed it into a high‐precision, high‐performance component. Through advancements in materials, tooth geometry, and backlash adjustment mechanisms, our servo worm gears overcome the technical limitations of conventional solutions and provide a meaningful, powerful alternative in many applications.

To this day, the servo systems market is strongly shaped by the assumption that planetary gearboxes are the only suitable solution for highly dynamic and highly precise applications. In fact, servo applications impose extreme requirements on drive technology. Frequent torque and direction changes, shock loads, and input speeds regularly exceeding 3,000 rpm are standard in modern ser‐ vo‐dynamic systems. Conventional worm gearboxes were historically excluded from these fields of application because of their high backlash, often more than 30 arcminutes and their limited efficiency, and were therefore systematically replaced by planetary gearboxes.
Over the years, this historical classification has solidified into a technical dogma: planetary gearboxes are widely considered the only option for high‐precision servo applications. Modern servo worm gearboxes, however, fundamentally challenge this per‐ spective. They offer designers new degrees of freedom and position themselves as powerful, precise, and robust alternatives to traditional planetary gearboxes, beyond established ways of thinking.

Design engineers often encounter challenges that planetary gearboxes can address only with significant complexity or excessive cost:

• Reduction limit of 1:10 per stage
  Planetary gearboxes require additional stages to exceed this limit. This increases axial length, weight, and mechanical complexity. At the same time, cumulative backlash increases with each stage.
• Right‐angle output arrangement (90°)
  In tight installation environments, a 90° configuration is a major advantage. Planetary gearboxes require an additional bevel gear stage for this arrangement, which increases installation space, complexity, and cost.
• Vibrations and noise
  The rolling contact in planetary gearboxes generates high acoustic frequencies. This can significantly increase noise levels
  and vibration excitation in a machine. Due to their sliding contact, worm gearboxes offer far more favorable acoustic behavior.

To overcome the weaknesses of conventional worm gearboxes, ATLANTA has further refined the high‐precision enginee‐ ring principles from its own servo gear units and optimized both the behavior and the performance of worm gearboxes. The result: Servo Worm Gearboxes.

• Optimized tooth geometry
  An increased tooth profile with a 15° pressure angle and a contact ratio greater than 2.0 reduces tooth‐to‐tooth backlash.
  A larger fillet radius at the tooth root reduces stress peaks, increases bending strength, and enables higher peak torques.

Conventional Tooth Profile
• 20° pressure angle
• Contact ratio 1.6 to 1.8
• Backlash: 20 to 30 arcmin
• Standard tooth height

Tooth Profile of ATLANTA Servo Worm Gearbox
• 15° pressure angle
• Contact ratio > 2.0
• Backlash: < 3 arcmin
• Increased tooth height

• Eccentric Backlash Adjustment Mechanism
  Eccentrically designed bearing covers enable precise adjustment of the center distance between the worm and the worm wheel.
  This allows the gearbox backlash to be set to ≤ 1 arcmin

• Precise High‐Speed Bearing Arrangement
  To eliminate the backlash of the input shaft caused by axial play, conventional tapered roller bearings are replaced with a back‐to‐back arrangement of precision angular contact ball bearings.
  These bearings ensure zero axial play, prevent any axial movement of the worm relative to the worm wheel, and enable opera‐ ting speeds of up to 6,000 rpm, as commonly required in servo applications.

• Materials and Manufacturing Quality
  Centrifugally cast high‐performance bronze according to ATLANTA standards increases pitting resistance and bending strength. Fine grinding of the worm shaft gearing achieves surface qualities in accordance with AGMA class 11, contributing to reduced backlash and lower noise generation.

• Lubrication
  A synthetic oil of ISO VG 220 ensures reliable lubrication at temperatures up to 150 °C, supporting thermal stability and wear
  protection.

• Backlash‐Free Motor‐Gearbox Coupling
  The form‐fit and force‐fit connection between motor and gearbox is provided by a high‐precision gear coupling. Wedge‐shaped clamping sleeves create a rigid, backlash‐free connection. The involute gearing of the input shaft compensates for slight misalignments and prevents fretting corrosion, which can occur during rapid changes in direction.

The technology of ATLANTA servo worm gears sets new benchmarks in servo drive engineering—both technically and economi‐ cally. Compared to conventional planetary gearboxes, they offer design engineers several decisive benefits:

• Single‐stage reduction ratios up to 52:1 without cumulative backlash.
• Low noise and vibration levels due to sliding contact.
• Compact machine layouts enabled by a 90° configuration without an additional angular stage.
• Reduced downtime,,as the gearbox can be readjusted rather than replaced.
• Lower inertia and reduced energy consumption, supported by aluminum housings and a compact design.
• Lower investment costs, since no multi‐stage planetary gearboxes with an additional bevel stage are required.