Advantages and Features
Roton’s rolled thread Torqspline® Lead Screws and high performance Quiknuts® provide the fastest linear travel available in a power screw. Torqsplines® use up to 30 starts to increase the thread lead, thereby increasing the linear movement output for each revolution of rotary input. Leads of up to 6 inches of travel per revolution are available from stock.
The highly burnished surface finish of the screw and low friction plastic Quiknuts® provide smooth actuation for today’s demanding stepper motor and servo motor drives. Conventional milled or cut multiple start screws will have much higher starting and run torques. Torqspline® Lead Screws provide improved wear and surface properties to insure users a longer service life and quieter operation requiring less power in a wide variety of applications.
Materials and Processes
All Torqspline® Lead Screws are made of special quality low carbon steel. This material provides an ideal combination of machinability, weldability, strength, toughness, and wearability.
All sizes are cold formed using a unique, highly accurate, thread rolling process which guarantees a smooth, high quality thread. Roton’s thread rolling process eliminates the interrupted grain flow of conventional milled, hobbed, or ground threads which increases yield, ultimate, and fatigue strengths. Alternate special screw materials are aluminum alloys and stainless steel, for applications requiring minimum weight or corrosion resistance.
Most applications can be satisfied by selecting from the stock sizes listed; however, OEMs may find an optimum design solution requires a special size or special features such as special diameter and lead combinations, metric diameters and leads, etc. For these applications, consult the Roton Application Engineering.
Extensive tooling and software resources can be utilized to assist the OEM designer in finding the very best solution for any application. A large tooling inventory exists for many special sizes not listed in Table 16. This inventory allows OEMs to purchase many “specials” quickly without the expense and delay of new tooling designed and built from scratch.
Plastic Quiknuts® provide superior service at rated operating loads. They should be well lubricated with a good quality, Extreme Pressure (EP) grease compatible with the operating environment. Quiknuts® can be used without lubrication but for maximum performance and wear life, lubrication is highly recommended.
Application engineering information is available from Table 16. Additional engineering information is available in the Application Engineering Section. Those designers not familiar with power screw applications are encouraged to review this section as well.
All Torqspline® series lead screws have lead angles greater than 25 – making them non self-locking. This means they can backdrive readily and many are used specifically for converting thrust to torque. Brakes or other holding devices will be needed with Torqspline® Lead Screws to sustain loads after they have been positioned unless the drive train itself provides enough holding torque. For applications demanding self-locking screws, refer to the Acme screw section.
Torqspline® lead screws and Quiknuts® provide a very low cost solution to fast actuation requirements, especially when compared to high helix ball screws and hydraulic systems. Torqspline® Lead Screws eliminate the leakage and sealing problems of hydraulic systems and generate much less noise. High helix Ball Screws produce excessive noise at high speeds when the balls collide with the ball deflectors. With only two moving parts, Torqspline® Lead Screws and Quiknuts® provide smooth, quiet action not obtainable with other mechanical or hydraulic systems.
Mechanical efficiencies for Torqspline® lead screws range from 60% to 75% and are much higher than Acme and Hi – lead® screws. As a result, most of the input torque is utilized to move the load and very little heat is generated.
The higher leads of Torqspline® lead screws demand more torque for a given linear load than Acme or Hi – lead® series screws. For maximum mechanical advantage users should consider Acme or Hi – lead® screws, whereas Torqspline® lead screws are used when high mechanical advantage is not required.
Roton’s Torqspline® lead screws and Quiknuts® are widely used and well suited for both manual and power drive applications including:
- Pick & place mechanisms
- Quick action door openers
- Robotic drives
- Factory automation drives
- Fast machinery slide drives
- Medical device drives
- Shuttle mechanisms
- Feed mechanisms