|method HPG-SThe manufacturing of these bevel-gear pairs having spiral toothing is carried out on very powerful gear cutting machines, which mill the teeth in continuos for the envelop generation by the cyclo-palloid tooth system.The main this toothing system is that the conical spiral wheels of constant tooth height are cut over the entire face using a milling-head with front-side multi-start in continuous motion. On the corresponding flat wheel (an imaginary wheel having a angle of 180° at the peak of the pitch cone) the lines of the tooth faces represent extended hypocycloid shapes. The blades which realize the flat wheel are grouped in such a manner to form a small portion of multi-start spiral.By selecting an appreciate spiral angle, also for these cones high contact values are obtained so that under load two or more teeth are always mesching. Consequently – due to the excellent quality of toothing obtainable – the best condition for silent run are ensured.The bevel-gear pairs of the Klingelnberg type have a constant tooth height along their entire face and therefore are less subject to assembling errors ( capacity of displacement from the pre-established size) and to any error of alignment on the axes thus offering higher resistance to stress. Due to these features, the use of Klingelnberg bevel-gear pairs offer – under the same dimension – a power transmission value higher by 30-40% as compared to a Gleason bevel-gear pairs. Furthermore, by selecting an appropriate run-away flight radius on which the blades are arranged, excellent factors of safety regarding any breakage of the tooth sides.
Definitely, it can be summarized that the Klingelnberg bevel-gear pairs permit large tolerances as to assembling and deformation under load without any substantial change of the contact position and the contact itself. This presents the main feature which is required for use under heavy-duty loads, for example on racing cars (such as Formula 1 or Rally) which use successfully the Klingelnberg bevel-gear pairs finished to the HPG-S grade after the hardening process.
Manufacturing of such bevel-gear pairs is realized by Brena S.r.l. using advanced manufacturing machinery (see enclosed Brochure). For this purpose, cutting tools which enable appropriate corrections individually and separately for each gear side are used, in order to obtain the desired limited and correctly positioned contact surface according to the indications established by the measuring machine which realizes mapping of the tooth sides.
As a matter of fact, the manufacturing cycle provides milling of the tooth sides after hardening using the HPG-S method. At the end of the job, the required contact surfaces and very silent run due to the very close surface roughness are obtained. The final quality after milling is better than ground finishing since any risk of burning spots on the teeth will be avoided which usually occurs when finishing the surface by grinding.