Two-Speed Gearbox Integrated into an Electrospindle

Machine tools, designed for universal application, can machine different materials. This needs both high cutting speeds for soft materials and high cutting forces for hard materials.

For soft materials, the 2-speed gearbox works at high speed and low torque (ratio i=1). The tool turns at the same speed as the motor. However for hard materials need more torque, for example, 4 times as much (ratio i=4). The tool turns at ¼ of the motor speed, but with 4 times the force.

Two-Speed Gearboxes is mainly used in machine tool drives for example vertical V1 machining centers, horizontal B5 turning machines, etc, but other applications that require either an increase in torque, or a reduction in speed, are possible.

The classic two-speed machine tool spindle drive gearbox

The classic two-speed machine tool spindle drive gearboxes based in planetary gears with ring have two important disadvantages:

  • They can not handle high speed spindle motors. The speed they can accept results in a mechanizing speed that is nowadays considered too slow.
  • Besides the system (spindle motor-gearbox-spindle) is too long.

The Servotak Two-speed gearbox integrated into an electrospindle: A custom solution

Until now, customers bought electrospindles and the two-speed gearboxes from separate suppliers and took care for the coupling system. While valid, this solution presents some issues.

Modern milling machines centers need powerful and compact solutions. Machine tool spindle drives require one of the most demanding motion solutions. Velocity errors, vibrations or transmission errors leave their mark on the pieces being machined. The Servotak Two-speed gearbox delivers the perfect answer to machine tool manufacturers who require high speed machining, smooth running, high precision and reliability.

We could simply design and build standarized and powerful two-speed gearboxes for high-speed applications, but we don’t – instead, we offer more: we take your specific requirements to develop custom solutions that fit them exactly. That's why customers value Servotak so highly when they have special needs.

Benefits

  • The development of a custom solution brings competitive advantages: it is compact, fits exactly the customer requirements and offers better performance than the alternatives.

  • Extremely compact design. High accuracy and high power density in a minimal space.

  • Coaxial design. Gearbox integrated in-line between a water cooled motor and a spindle inside a RAM. Large output bearings provide high tilt capacity.

  • A large hollow shaft, that goes through the system, to facilitate the installation of hydraulic draw bar and spindle coolant system.

  • Smoother motion due to optimized Servotak gears

  • High speed for soft materials and high torque for hogging out steel or hard materials. Increased production rates thanks to high speed gears. Greatly reduces cycle times

  • Better performance compared to conventional two speed gearboxes

  • The low noise shift mechanism meets strict machine tool requirements. The actuator used for the speed change is integrated into the gearbox design.

Our customer

Our customer is one of the most prestigious European technological research institutes, specialized in machine tools. In 2010, it undertook an ambitious project: designing a compact electrospindle, two-speed gearbox and tool clamp system. They contacted several market-leading European companies, specialized in the field of gearbox manufacturing. Many companies that had initially expressed interest in the project found it's complexity overwhelming, and decided to leave. After several conversations with project managers, Servotak was awarded the project, as a recognition to it's experience and expertise in high speed gear design for machine tools.