Consortium investigates face gear grinding

An Estonian-led consortium with partners from Italy and the Czech Republic is performing research into the development af a cost-effective technology for face gear grinding.
A consortium led by Feanor, including partners from Italy and the Czech Republic is performing a research for the development af a cost-effective technology for face gear grinding. Face gears have been known and studied for many years, but since they were used for low power and low speed, the requirement for a constant speed ratio was not very important. With the advent of high power and speed requirements, face gears have been driven out by conventional bevel gears, which are easier to be manufactured.

Face gears have important applications in helicopter transmission systems.

They proved to be effective also with insufficient lubrication, thus increasing the reliability of the aircraft, and they work also with bad alignment between pinion and the rotor gear.

Helicopters using transmission systems based on face gears have a higher safety and survivability.

The target of the Facegear project is to study a cost-effective method for the manufacturing of face gears, thus increasing their application in the helicopter industry.

Face gears have some other natural advantages, compared to bevel gears, such as: 1.

the pinion is a normal spur gear which axial position has no influence on the meshing zone provided its face is adequate (see point 2 of the proposal summary).

2.

assembly time is reduced because only the axial position of the face gears needs to be set.

3.

Lapping is not necessary because all gears irrespective of their tooth numbers or shaft angles may be interchangeably meshed with the common pinion upon which the particular generating hob geometry is based.

4.

There is no axial load on a pinion with straight spur teeth.

5.

The meshing is smoother due to oblique contact lines and high contact ratio.

6.

Face gears provide high transmission ratios in one stage.

7.

Cost effective manufacture on conventional CNC gear hobbing machines straddle mounted pinions, provided that the calculation is correct.

8.

Zero backlash transmission for positioning or measuring machines can be easily obtained.

9.

Face gears have high strength teeth and good contact geometry, which give high torque capability.

Objectives of the proposed EU project are a calculation software for face gear geometry, a cost-effective gear cutting technology for face gears and a measuring system for the geometry of face gears.