Hollow Rotary Tables,Cam Indexers,Planetary Gear Reducers 
RV (Rotary Vector) cycloidal gearboxes use an eccentric input shaft that causes a cycloidal disc to orbit within a ring gear.This orbital motion is then converted into a high-torque, low-speed output rotation.
The main components of an RV cycloidal gearbox are the eccentric input shaft, the cycloidal disc, the ring gear, and the output shaft.The eccentric input shaft causes the cycloidal disc to orbit within the ring gear, creating a high-torque, low-speed output rotation.The rolling contact between the cycloidal disc and the ring gear results in a smooth, low-vibration motion.
TallMan Robotics RV Cycloidal Gearboxes: Mechanics and Technical Overview
RV-E cycloidal gearbox integrates the main output bearing directly into the gearbox housing. A first-stage spur gear reduces input speed before driving two eccentric crankshafts. Each crankshaft rotates a cycloidal disc against a fixed ring of hardened pins. The disc oscillation converts to pure output rotation through a carrier plate.
The table below displays a selection of RV-E Main Bearing Built-in Type Cycloidal Gearboxes with images and full specs.
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Industrial applications cases with RV Cycloidal Gearboxes
Automotive Robotics: Spot welding robot — J1 waist axis drive
An RV-E gearbox drives the J1 waist axis of a 200 kg payload spot welding robot. Reduction ratio is 192:1. Rated output torque is 3,136 N·m. The welding gun and transformer arm produce a combined moment load of 2,400 N·m at the output flange. The RV-E built-in crossed-roller bearing absorbs this moment directly. No external slewing ring is needed. Torsional stiffness is 980 N·m/arc-min. This limits waist axis angular error to 2.4 arc-seconds under full gun load. TCP positioning repeatability holds ±0.05 mm across a 2,100 mm reach envelope. Input speed runs at 1,500 RPM from a 4.0 kW servo. The hollow shaft — 65 mm bore — routes the gun power cable and coolant hose through the waist axis without an external cable guide.
The 2,400 N·m moment load requires a large-diameter bearing at the output. The RV-E built-in bearing handles this load inside the gearbox body. A standard RV unit without the built-in bearing needs a separate 220 mm slewing ring, adding 95 mm axial length and a second alignment datum to the waist joint.
Machine Tool: Turning centre — C-axis spindle indexing drive
Simultaneous radial and axial cutting loads rule out a standard RV unit. The built-in crossed-roller bearing absorbs both load vectors in one component. A harmonic drive at 1,850 N·m deflects 0.15–0.22 mm at the tool tip under interrupted cut. The RV-E limits this deflection to 0.038 mm — keeping the contour error within the valve seating tolerance.
FAQs about RV Cycloidal Gearboxes
- How to measure RV gearbox moment rigidity?
Apply pure bending moment at output flange. Measure angular deflection with laser encoder. Rigidity = Moment / Deflection (Nm/arcmin). - Why does RV gearbox require two cycloidal discs?
One disc creates unbalanced radial force. Two discs with 180° offset cancel vibration and double torque capacity. - Which lubricant suits RV cycloidal gearboxes?
ISO VG 68 to 220 synthetic oil with extreme pressure additives. Oil viscosity depends on input speed and operating temperature. - How to calculate RV gearbox reduction ratio?
Divide input helical gear teeth by output pin carrier teeth. Multiply by cycloidal stage ratio. Formula: Ratio = (Z_helical_in / Z_helical_out) × (Z_pins / (Z_pins – Z_lobes)).
