2016-07-27 03:30:17
Each year, engine and motor power increases require more powerful angle gear heads. Engineering development in mechanical engineering, toolmaking industry and industrial hand tools call for higher rotating speeds while smooth and easy movement of the tool is maintained. Smoother-running gears are also needed to combat dynamic noise. Apart from bearing and housing stiffness, the overall design and gear dimensions are essential for gear system optimization.
The Palloid and the Zyklo-Palloid Hobbing Process
Palloid-toothed gears are based on a technical development from straighttoothed to spiral-toothed bevel gears. Thereby the teeth are hobbed in a continuous procedure with a conical hob. “The combination of this continuous process on a single thread tool leads to a very accurate pitch of the teeth,” said a Suhner spokesperson.
“Since the Zyklo-Palloid gear hobbing meets all high-quality manufacturing prerequisites, one-off, small and large lot size production can be applied equally,” said the spokesperson. In the Palloid-System, since the teeth are hobbed in a continuous process, the Module (Mn) can be freely selected. “Therefore, a high flexibility for the gear dimensioning and bevel gear calculation is provided,” said the spokesperson.
A further development on the Zyklo- Palloid-Toothing (soft-cut) is named “HPGS hard cut.” The thermal deformation, caused from heat treatment, can be eliminated with boron nitride coated knives. Therefore, the surface quality on the tooth flanks will reach grinding quality, according to DIN 3965, Part 3 (Quality 4 – 6 is available).
“In combination with the material, the surface treatment and the adjustment of the required lubrication, spiral bevel gears are one of the best solutions when it comes to redirecting the maximum torque in other directions. All these can be achieved with small space and high mechanical efficiency,” said the spokesperson.
What Must be Considered for the Engineering?
Because of the sophisticated combination of the different spiral bevel gear angles, the circumferential force is divided among several components that can lead to significant axial forces. Therefore, gear design depends a lot on the bearings. The bearings have to absorb all the axial forces so the bevel gears do not move under load.
Any movement would affect the contact pattern of the teeth, which would result in edge wear that could destroy the entire gear. Just as important as the bearing, is the stiffness and the geometrical accuracy of the case. All the advantages of spiral bevel gears can be accomplished when gears are optimally positioned and perfect tooth contact is maintained.
When dimensioning the gear geometry, several criteria must be considered: required ratio, number of teeth and space conditions. The criteria must be decided at the start of the engineering process. When the shaft angle ? 90° or the axis is offset, an axial-offset gear, called hypoidgears, needs to be constructed.
For more information contact: Suhner Industrial Products Corp. Hwy. 411 S. at Suhner Drive P.O. Box 1234 Rome, GA 30162-1234 706-235-8046 info.usa@suhner.com www.suhner.com IMTS 2016 Booth W-1474
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