Why is the upper saw wheel of a band saw lighter than the lower saw wheel?

Regarding why the upper saw wheel of a woodworking band saw machine is 2.5-5 times lighter than the lower saw wheel, it should be considered in terms of the working method and use requirements of the band saw. The wheel with the saw blade is called the saw wheel, and the upper saw wheel is called the upper saw wheel. It is the driven wheel; below is the lower saw wheel, called the driving wheel.
The upper saw wheel is installed on the sliding column of the saw wheel lifting device, and the lower saw wheel is installed on the bearing frame. The diameters of the two wheels are the same, but the weights are different. The upper saw wheel is light and the lower saw wheel is heavy. The load of the upper saw wheel bearing is easily driven by the lower saw wheel, so the weight of the upper saw wheel should be as light as possible.
When the band saw machine starts and brakes, the upper saw wheel can be rotated or stopped at any time; while the lower saw wheel is a solid wheel made of cast iron, which is heavy and can reduce the load on the bearing of the lower saw wheel when the saw blade is tensioned. When the saw wheel is idling, the lower saw wheel can store part of the energy and act as a flywheel. When sawing wood, the stored energy can be released to alleviate the impact caused by uneven wood material or friction and stabilize the speed of the saw wheel. The role of.