Precision Reduction Gear RV E Series / C Series / Original Series

Contributing to society with our ‘Moving it. Stopping it.’ technologies Nabtesco's Nabt Nabte co's ' technologies te techn ogies ec echnologies es support ng supporting supporting upportin pp ppo societ society society o iet t ty Nabtesco manufactures products which are used in everyday life. Our high-accuracy components are essential for moving objects; they may be rarely visible, but are the foundation of everyday objects that you see moving and wonder how. Nabtesco’s technologies are found throughout objects that move and stop people’ s lives. Do or s Ro bo ts Precision reduction gears precisely...

CONTENTSWho is Nabtesco? The key words for Nabtesco are ‘motion control'. We use our strengths in the fields of component and systems technologies to develop highly creative products. Through the Nabtesco Group as a whole, we can also utilize our advantage of expertise to maximum effect in order to further enhance these strengths. In the air, on land and at sea, we have a large share in various fields of both international and domestic markets. Nabtesco will continue to evolve by utilizing its strengths in many fields and by exploring the possibilities of the future. April 2002 Initiation of...

Precision reduction gear RV™ The RV E, C, and Original Series are family of planocentric reduction gear mechanisms designed for precise motion control. The mechanisms incorporate a large number of simultaneously engaged gear teeth, and have compact, lightweight and highly rigid construction that is strong against overloading. Furthermore, minimal backlash, rotary vibration and inertia assure rapid acceleration, smooth motion and extremely accurate positioning. The Precision Reduction Gear RV is ideally suited for precision mechanical control in factory robots, machine tools, and assembly and...

Features and construction of E series Integrated angular ball bearings Benefits: • Increases reliabilty • Reduces overall cost Main bearing Attributed to: • Built-in angular ball bearing construction improves the ability to support external loads, increases moment rigidity and maximum allowable moment. • Reduces the number of components required. • Simplifies installation. 2-stage reduction Benefits: • Reduces vibration • Reduces inertia (GD2) Attributed to: • Low speed rotation of the RV gear reduces vibration. • Reduced size of the motor coupling part (input gear) lowers intertia. All main...

Precision reduction gear RV™ Features and construction of C series Hollow shaft structure • Cables and other lines can pass through the reduction gear • Allows space saving design Main bearing Integrated angular ball bearings Benefits: • Increases reliabilty • Reduces overall cost Spur gear p gear Attributed to: • Built-in angular ball bearing construction improves the ability to support external loads and increases moment rigidity and maximum allowable moment. As a result, this model can be used for the rotary axis. • Reduces the number of components required. • Simplifies installation. 2-stage...

Features and construction of Original series 2-stage reduction Benefits: • Reduces vibration • Reduces inertia (GD2) Hold flange Attributed to: • Low speed rotation of the RV gear reduces vibration. • Reduced size of the motor coupling part (input gear) lowers intertia. All main elements are supported on both sides Benefits: • Higher torsional stiffness • Less vibration • High shock load capability Detail: • Crankshafts are supported on both sides of the reduction gear as shown below. Shaft + hold flange Crankshaft through hole Crankshaft through hole RV gear Rigid supporting structure Clearance...

Application examples C series Robot swing axis • Allows space-saving design • Main bearing is not required on robot side. Robot arm • As cables can be passed through the arm, environmental resistance increases. • Wider operating angle. Indexing table • The table can be made into a hollow shaft struct

Robot wrist axis As shown in the figure(right), the input gear can also be supported within the reduction gear mechanism. Pl e a s e c o ntac t N a bte s c o fo r m o re details. Original series Robot swing axis

Principle of speed reduction 1st stage …Spur gear reduction • An input gear engages with and rotates spur gears that are coupled to crankshafts. Several overall gear ratios can be provided by selecting various first stage ratios. 2nd stage …Epicyclic gear reduction • Crankshafts driven by the spur gears cause an eccentric motion of two epicyclic gears called RV gears that are offset 180 degrees from one another to provide a balanced load. • The eccentric motion of the RV gears causes engagement of the cycloidal shaped gear teeth with cylindrically shaped pins located around the inside edge of...

Rotary direction and speed ratio Both the E series and Original series may be used in various ways. The following figures show six combinations of the rotary direction and speed ratio. Use the following figure to select a mechanism most suitable for your application. 1. Case fixed, shaft output 2. Shaft fixed, case output Input: Input gear 1 i =— R 5. Shaft fixed, input gear output Input: Input gear 1 — i=— — — R–1 4. Case fixed, input gear output 3. Input gear fixed, shaft output Reduction gear Speed increasing gear Input: Shaft Input: Case 6. Input gear fixed, case output •The “i” in the above...

Principle of speed reduction Rotary direction and speed ratio The rotary direction and speed ratio of the C series are shown below. 1. Case fixed, shaft output 2. Shaft fixed, case output Input: Input gear 1 i = — R1 Input: Input gear 1 — i = — — R1-1 4. Case fixed, input gear output 5. Shaft fixed, input gear output Reduction gear Speed increasing gear Input: Shaft Input: Case 3. Input gear fixed, shaft output 6. Input gear fixed, case output Installation example (motor installed on case side of reduction gear) 1. Case is fixed, shaft output 2. Shaft fixed, case output Mechanism block drawing...