Gearing up for Flexibility

The common theme for new gearheads, servo actuators and other products that offer geared motion, along with lowering product costs and providing more compact designs, is application flexibility. A wide variety of product configurations and specialized features, such as built-in sensors, provide alternatives that offer solutions for specific project requirements.

“Higher speed, higher torque products and an increase in specialized applications define our goals for new gearheads,” says Mike Anselmo, applications engineering manager for WITTENSTEIN. “Companies are always trying to increase throughput and, with gear train systems, speed can be a limiting factor.”

To achieve higher levels of performance, manufacturers are creating an array of configurations of their basic products and are also offering advanced features. One example is the use of intelligent sensor technology in WITTENSTEIN's planetary gearboxes. Alpha IQ provides the ability the use the sensor for system diagnosis, process monitoring or process control.

A modular sensor flange that replaces the output side of the gearbox can be used to monitor radial loading, torque, side loads and speed. The TP Sensor Gear makes it possible to communicate using different protocols (RS-232, voltage or current interface or a fieldbus via an AnyBus gateway).

“The main advantage is the ability to monitor X and Y radial loading and torque,” says Anselmo. “What makes it unique is that with most torque sensing products, you can't monitor radial loading but this approach can do both.”

Eugen Elmiger, director of sales and marketing for Maxon Motors, says with a flexible range of products and technical know-how, suppliers are able to fulfill nearly any customer requirement. “The key areas for new gearhead products are efficiency, cost, innovative materials and the combinations of it to create a long lifetime,” he says.

He says their focus is constant improvement on the existing gearhead platform and further development of new gearheads, especially small micro technology gearheads. One specific example he mentions is the use of ceramic in the gearheads.

The company's Koax-Drive KD32 was developed because of an increasing market demand for low noise applications. The Koax products have found a niche in medical technology applications where high torque is a must but quiet operation is a significant advantage because it makes handling instruments a more pleasant experience. He says their full range of the 32 mm gearheads will be upgraded soon.

Another area that fits with the desire of gearhead makers to provide flexible product options is the ability to customize their line-up and provide more highly integrated product-level solutions.

Elmiger says development of intelligent, mechatronics gear drive systems can also offer a wide range of features for customers. He cites the example of an intelligent mechatronics' gear drive system consisting of a spur gearhead, combined with a low backlash right angle gear head, motor, feedback system and positioning controller with bus system.

He says many customers want more complete subassemblies from one supplier — motor, gear mechanism, their own mechanical coupling if necessary, electronics and software in one package. Products can be individually designed, optimized and executed with all the engineering disciplines where the supplier offers expertise.

Ultra-Flat, Zero-Backlash Gearhead
The new SHD gearhead from Harmonic Drive LLC delivers zero-backlash, 1.5 arc-min positional accuracy and ±5 arc-sec repeatability. The gearhead combines high-precision gearing and a high-capacity cross roller bearing. This size 14 unit has an outer diameter of 70 mm and is just 17 mm in length. It has a rated torque of 33 inch-lb and a maximum torque of 310 inch-lb. Available gear ratios are 50:1 and 100:1.

This product is designed for OEM robotic applications. The design allows the gearhead to be incorporated into the machine housing by providing the necessary motion control components such as the harmonic drive gear and cross roller bearing. The product is capable of supporting a large output torque and moment load.

Drum Motor Improves Efficiency and Safety
Providing a space-saving motor drive solution, a redesigned drum motor 127i from Interrol features an internal gearing system with a 97 percent efficiency that lowers energy consumption and reduces noise levels while operating at full capacity. It is designed for OEMs of specialty machinery, automation integrators and end users in the food-processing industry. A thermally protected motor, it offers IP67 protection along with spring-loaded and labyrinth seals that prevent contamination and oil loss.

The gearing system features no external moving parts, making the unit safe and quiet. It is available with 3-phase motors for designers searching for a simple component that minimizes space. The drum motor has a conveying speed up to 315 fpm with 1.0 hp. The drum motor can operate in temperatures up to 104F and is virtually maintenance-free, with oil changes recommended every 20,000 hours.

Rotary Servo Actuators
The design of the new TPM+ rotary servo actuators from WITTENSTEIN/alpha gear utilizes helical gears for smoother, quieter operation. The units provide higher power densities than their predecessors and offer a compact, sleek design.

High rotational rigidity and a clamping, hub-free integration between the motor and gear make applications with load-to-motor inertia ratios of more than 50 easily obtainable. This allows applications to utilize much smaller motors and decrease the torque used by the motor to accelerate itself. Increased efficiency allows a natural convection-cooled motor to work where a water-cooled design was once necessary.
With these new units, the planetary gear reducer and ac servomotor are closely integrated, with the sun gear and rotor joined without a coupling. The space envelope is reduced by up to 20 percent compared to previous models.

Precise Repeatable Zero-Backlash Positioning
A new zero-backlash spur gearhead from MicroMo Electronics is designed for applications requiring precision positioning with high resolution and low torque requirements. The gearhead weighs 4.5 to 5.7 gm while providing a maximum continuous torque of 15 mNm and intermittent torque up to 25 mNm. The zero-backlash spur gearhead comes with four standard ratios for precise positioning, speed reduction and torque multiplication.
The gearhead can be combined with a motor and encoder for a complete miniature dc drive system. The motor and gearbox can be combined with magnetic or optical encoders to allow for precise control of speed and direction of rotation, as well as the positioning of the drive shaft.

Parallel Shaft Von Weise Replacement Gearmotors
New VWDIR84 parallel shaft, fractional horsepower gearmotors from Bison Gear & Engineering Corp. are designed as Von Weise Drop-In Replacements. The Bison VWDIR84 is available in 13 standard models, with output speeds from 6 to 85 rpm and torques from 50 to 600 inch-lb. Three models are powered by a dual voltage (115/230V), dual frequency (60/50 Hz) permanent split capacitor 1/12 hp ac motor.

Ten standard dc models are available driven by either 12 or 90V permanent magnet dc motors. The Bison Drop-In Replacements for VW84 gearmotors feature standard 0.75 inch output shaft diameter and built-in foot mounts.

The design features a reasonably high overhung load capability of 250 lb that makes it ideal in applications like food service, agricultural and woodworking equipment, as well as electrical switchgear, conveyors and automated file systems.

6- to 81-mm Precision Gearheads
Custom-made, precision gearheads from Maxon provide a solution when the motor for an application is powerful enough for motion, but has too high a speed and too low a torque. Maxon offers an extensive line of standard planetary and spur gearheads in more than 600 variations with diameters ranging from 6 to 81 mm.

Maxon also offers custom-made solutions, including a special planetary gearhead with two speeds on the output side. The motor shaft goes through the gearhead, resulting in two speeds with a mechanically fixed reduction ratio. The company also produces worm gearheads and spindle drives, in addition to special spur and planetary gearheads.

Reducer Gearbox Simplifies Bulk Conveying
Baldor's new reducer gearbox family for heavy-duty material handling applications, the Dodge MagnaGear XTR, allows system builders to achieve substantial weight and space savings.

Available in either parallel shaft or right-angle drive configurations, all the larger sizes of the gearbox employ a planetary output stage. This can reduce size substantially, by as much as 25 percent, compared with all helical or bevel gearing systems. Higher specification bearings than is usual in this market sector will help OEMs reduce maintenance costs for users.

The MagnaGear XTR family offers a choice of eight sizes, rated for output torques from 11,300 to 103,950 Nm (100,000 to 920,000 lb-inch). A proven planetary output stage is used on the four largest sizes. Speed reduction ratios from 8.5:1 to 63:1 are available depending on the model and configuration chosen.

Gen II Helical Planetary Gearheads
The Stealth Gen II Gearheads from Parker's Electromechanical Automation Div. provide performance enhancements. Improvements include higher radial load capacities that are up to four times greater and increased service life resulting from more robust bearing support, dual angular contact bearings to support the output carrier, full complement needle bearings to support the planet gears and optimized gearing geometries.
Internal design changes allow for one fill level for any orientation, resulting in shortened part number designation and simplified order placement. The redesign also incorporates a simplified motor mounting kit design.

New “universal” mounting kits (designated “MU”) are designed to be used across multiple product lines, so axes that demand high precision, mid-range or lower precision utilize the same mounting kit part numbers within the same frame size.