The most important factors in choosing the Tolomatic brand actuator were its overall torque and its compact design.
Rochester, NY (Vocus) December 7, 2010
As the company that pioneered the development of the bevel gear used in vehicle differentials, Gleason Corporation demands that its latest automated gear grinding machines be in the forefront of efficient and high-quality gear production. One key to quality is making sure that the work piece is well lubricated and does not become overheated during the grinding process. That’s why when Gleason needed a replacement actuator to position a heavy coolant head on its Phoenix® II 275G gear grinding machine, the company turned to Tolomatic, Inc. of Hamel, Minnesota for a solution.
“The Phoenix II 275G gear grinding machine is designed to create a fine finish on the mating surfaces of bevel gears that have already been rough cut,” says George Chamberlain, a Gleason design engineer. “Once the mating surfaces are properly ground, the gears are interchangeable in gearing systems and run efficiently and quietly. Grinding is becoming the preferred bevel gear finishing method, as opposed to the traditional gear lapping process, in which mating gears are lapped together with an abrasive slurry to create a matched pair.”
Positional accuracy is critical
To insure that the gear grinding process produces the best finish on the gear surfaces, a flow of lubricating coolant needs to be precisely directed at the grinding wheel’s point of contact with the gear at all times. “Positional accuracy of the coolant heads is necessary because you have to flood the point of contact with coolant so you don’t burn the part,” says Chamberlain. “The coolant also provides lubrication and flushes away the grinding debris created from the process.”
In the original design of the machine, an electric actuator was responsible for moving a 50-pound manifold of coolant jets in small increments as the grinding wheel was consumed and changed dimensions. However, the original motor/actuator used in the machine sometimes lacked the necessary torque to move the heavy coolant manifold. It was found that when the actuator was overloaded due to increased friction in the system, it would stop and sometimes lose its position.
“This would cause the machine to send a message to the operator to investigate the situation before the start of the next cycle.” says Chamberlain. “The machine would indicate a positional error and then you would have to re-reference the position of the coolant”. Needless to say, this was non-productive time that reduced overall productivity for some of Gleason’s customers.
Solution is powerful and compact
One solution would have been to replace the original actuator’s stepper motor with a more powerful servo motor, but the actuator Gleason was using didn’t allow such a replacement. And, even if it had, there was insufficient space inside the machine’s grinding chamber to accommodate a motor that was physically larger or more powerful. That’s when Chamberlain consulted with Brian Mulholland of Hughes Hi-Tech in Clarence, NY, a distributor for Tolomatic, Inc., and learned that Tolomatic actuators could accept a more powerful servo motor. In addition he found that the Tolomatic RSM rod-style screw actuator was not only powerful but extremely compact.
“The most important factors in choosing the Tolomatic brand actuator were its overall torque and its compact design,” says Chamberlain. Most rod-style actuators have a screw that is driven by a motor connected inline. Tolomatic’s RSM actuators feature a reverse-parallel motor drive where the motor is mounted along side the actuator and drives the screw through a toothed belt and pulley assembly. “Every other actuator we looked at had the motor bolted to the backside of the actuator, making the units too long to fit into our design window,” he says.
The Tolomatic RSM rod-style actuator series is designed for high performance, high thrust, durability and compact mounting flexibility. With thrust capability ranging from 70 pounds to 7,000 pounds, even the smallest 12-inch model had enough power for Gleason’s application. The product line also features black anodized extrusion designed for rigidity and strength, ball screw, roller screw or acme screw options and robust internal guide bearings to support the screw assembly throughout its entire stroke.
For more than 50 years, Tolomatic has been a leading supplier of electric linear actuators, pneumatic actuators and power transmission products for factory automation. Its extensive product line also includes servo-driven high-thrust actuators, servo- and stepper motors, stepper drives, and configured linear-motion systems. Tolomatic’s electric linear and pneumatic actuators are used in a variety of industries, including the packaging, material handling, medical, food processing, automotive, semiconductor and general automation industries. For more information about the RSM actuator series with reverse-parallel drive, contact Tolomatic, 3800 County Road 116, Hamel, MN. Phone: 763-478-8000 or 1-800-328-2174. Web site: http://www.tolomatic.com.