Unlike other transmission method, gear spindle is one of its kind that contains no further transmission mechanism but drive the load directly from the gear itself. As a result, gear spindle is much more powerful regarding its applications when it’s about heavy duty cutting or endurance grinding.
The development of spindle technology started from the textile machinery and to the machine tool application it has been for about 120 years. For milling and turning machines, there are mainly belt driven, motorized, gear driven, direct driven, built in, etc.
If compared with other driving mechanisms, direct drive and gear drive spindles are designed with stronger torque power, faster and more accurate activation, while is with larger area coverage. Therefore, when it’s about center-less grinding, direct drive spindle is most like to be the option, and gear drive is more like reinforcement.
Normally, a machine tool could contain several spindles, such as the headstock and tailstock spindles on a bench lathe machine, and the primary spindle is usually is the biggest one and the longest length if it is on the turning machines. For that reason, if the references to the spindle without further qualification imply that the targeted subject is the primary spindle.
Some turning machines (i.e. turning centers) that specialize in mass-volume quantitative production have a group of 5, 7, or even more primary spindles. These are called multi-spindle machines such as gang drills and screw machines.
The driving mechanism
Gear spindles can be driven by a wide variety of power sources and are usually designed for medium machine base shell so that they can accommodate with the many kinds of shell body, which eventually offer greater machining strength onto the work pieces.
Specific and purpose-oriented
In the spindles market, some are specifically designed for certain models or machine tool types, such as turning spindles, milling spindles, drilling spindles, and so on. However, only with an appropriate installation of the spindle, can machine tools able to perform the designed capacity.
In addition to the direct drive motors, examples of spindles include a wide variety of other designs. On a grinding-turning machine, the spindle is the heart component of the headstock case. On the other hand, in rotating-grinding woodworking machinery, the spindle is the part component on which shaped milling cutters are equipped for cutting features, such as profiles of rebates, beads, and curves into moldings and similar grinding and milling tasks.
The differences between direct drive and gear spindles
Though the two models are similar in many phases, there are several features lay in between. In rotating-cutter metalworking machine tools such as machine centers, tapping centers, and drill presses, the spindle is the shaft to which the tool is attached to the machinery as just one part of the big picture via a chuck.
Varieties of spindles include grinding spindles, electric spindles, machine tool spindles, low-speed spindles, and high speed spindles are all designed by some functionality basis. If, for example, a grinder is equipped with belt-driven spindle, the torque then is largely weakened. For belt-driven spindle, it is consisted of spindle and bearing shafts held within the spindle housing, and the belt-driven spindle is powered by an external motor rather than an in-built, or did a shaft-driven connect via a belt-pulley system. With this design, the pulley is not as stable as the direct drive mechanism and thus the belt materials become one of the key variables concerning the machinery operation.
Therefore, the gear spindle is different from direct drive in the fact that the transmission mechanism it deploys. The former is with no further transmission medium, granting much direct power transmission, but at the same time, with less buffering space if there is more torque needed.
As a result, for grinding machine the spindle option would normally be direct drive while for other machine tools such as milling and tapping, gear spindles are more likely to be used in the case because grinding requires more marching torques than other machine tools does.