A right-angle gearbox – what is that?

What are the most common right-angle gearboxes?

The most common single-stage gearbox types are bevel gearboxes and worm gearboxes. In general, however, right-angle gearboxes are constructed by combining different gearing types.
Bevel gearboxes with intersecting axes can, for example, be constructed using straight-cut, helical-cut or spiral-cut gearing. So-called hypoid bevel gearboxes have spiral-cut bevel gearing. In these gearboxes, the axes cross with an axis offset. This has the advantage that the technically useful gear ratios are larger than with classic bevel gears.

How a right-angle gearboxes can be combined?

This can be done by using bevel gearboxes together with other types of gearboxes. Often this is done with planetary gearboxes. These can be connected upstream, as well as downstream. In either case, you have a great variety of total transmission ratios. Accordingly, there is also a wide range of applications for these gearboxes.

How good is the efficiency?

This is generally lower for bevel gearboxes than for coaxial planetary gearboxes. Quite simply because high axial forces and radial forces are in play here. These forces are intercepted by the bearings, however. Nevertheless, there are losses, which are reflected in the lower efficiency.
Another shortcoming of bevel gearboxes is that they do not run as smoothly. In addition, they can only transmit lower torques than planetary gearboxes, for example.
In the special case of hypoid gearboxes, however, operation is smoother and the torques can be large compared to bevel gearboxes. However, this is "paid for" with a high load on the bearings in the bevel gear stage.

When are these gearboxes used?

Most often, when there is little space. But also if the application requires a special arrangement of input and output. For example, if the shaft is designed as a hollow shaft because cables are routed through it.