Two-speed spindle drive gearboxes simplify maintenance

This new range of two-speed gearboxes is available in five sizes. The torque transmitted in the low-speed configuration is nearly twice the torque obtained by the previous generation of gearboxes, which was itself often market-leading performance. The range comprises the following models: 190 (800Nm), 220 (1000Nm), 250 (1500Nm), 280 (2500Nm) and 350 (7000Nm).

The exceptional transmitted torque has an obvious impact on the performance of machine tools in roughing work. This torque improvement is the result of a completely new design of the core gear train within the gearbox. Distribution of the torque capacity over each component of the new transmission system is optimized, which allows substantially higher torques to be transmitted.

Another feature of the RAM High Torque units is that there are no internal electronics; this improves reliability and simplifies maintenance. External housings have, nevertheless, been designed to offset the locations of all the electronic sensors used for spindle applications. This means that sensor replacement no longer necessitates several hours of disassembly.

Speed change actuation is hydraulic, so that the pressure circuits routinely available on all types of machine tool can be used.

Easy integration

The two-speed gearboxes are built into the ram, in line between the water-cooled motor and the tool drive spindle. This means that the RAM High Torque can easily use the same coolant feed as the motor, as well as the lubrication circuit already installed for the spindle.

The design features a particularly large diameter (28-54mm) hollow main shaft that is capable of accommodating a hydraulic draw bar as well as easy flow of high-pressure cutting lubricant for swarf removal directly at the tool.

As in the case of built-in motors, the design of the new RAM High Torque also avoids any redundancy of bearings on the shaft line, thereby eliminating any alignment and/or overheating problems and increasing the overall reliability.

The assembly configuration of the RAM High Torque facilitates integration and maximises efficiency while minimising vibration and noise. Despite very high speeds, vibration and noise are reduced to a minimum by precise dynamic balancing of the rotating components. Low angular play of 15' for a 1:1 ratio and 20' in reduction ensures position control during tool changes.

In addition, the ISO 5 quality gears are fully treated and ground, further improving noise and vibration levels and giving extremely high efficiencies.

These characteristics enable the RAM High Torque to attain very high rotation speeds (up to 12,000rpm for the small sizes), which is essential for obtaining high-quality surface states in finishing operations. Even the largest sizes can attain speeds of up to 8000rpm.