Conveyor Belt Control: BLDC Motor Applications
Fully Integratable Drives Ensure Maintenance-Free Operation
The trend towards ever-smaller products is increasing. For this reason, assembly technology equipment is now also operating with ever-smaller components. Belt conveyors just like those that work with standard-sized components are now being offered for transporting high-unit loads, safely. Optimized to meet the special requirements of transporting small items, in many cases they are the product of choice. Robust materials and durable, maintenance-free components guarantee high operational functionality over long periods of time.
In the world of manufacturing there are still a few areas in which it is quite sufficient to transport components manually from one section to the other, but, for high-unit loads, automated solutions have become essential. With this in mind, Henry Ford deployed belt conveyors for mass production even back in his day. The Vetter engineering company is proving with its micro belt conveyors that this principle is transferable to assembly technology for small components too. And their compact, modular concept can also be tailored to accommodate special user requirements.
A compact design also requires compact motors, and for this reason the manufacturer works with the micro drive specialist, FAULHABER, based in Schönaich. This has given rise to a whole range of standard and customized compact belt conveyors.
Conveyance means movement. Small components in motion do, however, tend to “go astray” once in a while. In order to ensure smooth production, it is essential that nothing gets jammed on the conveyor belt. To avoid any such disruptions and at the same time facilitate easy, rapid integration into existing or new installations, the manufacturer utilizes a completely encased, “motorless” conveyor belt. All key components of the conveyor system are completely enclosed, with a smooth outer surface and are almost completely covered by the actual belt itself. This in turn provides usable area only, without any awkward (drive) attachments. The cleverly designed modular structure makes assembly much easier, and even variants for special requirements can be supplied virtually on a ready to use basis.
A belt conveyor must provide the right user-specific width and length. On top of this there is automatic pre-tensioning of the belt and a drive. The modular design meets these requirements perfectly: the idler roller for the conveyor belt is connected to an aluminum-section, “supporting element” that can be cut to the individual length required. The belt is driven by another module comprising a micro drive and a roller drive on the other side of the supporting element. If the supporting element (which is only needed for the variable length) is omitted, the overall length of the conveyor unit can even be scaled down to 200 mm – with a height of just 30 mm and a width of 60 mm.
The drive integrated into the belt conveyor has none of the troublesome, protruding components that make installation more difficult. All of this can only be achieved by using extremely compact drives that are much narrower than the diameter of the transportation unit or the idler rollers. Depending on the conveyor design, the manufacturer uses either 16-mm brushless dc servo motors or coreless dc motors of 23 mm to 35 mm diameter from FAULHABER.
These motors come with a long-life planetary gearhead as a pre-assembled unit, thus combining motor and gear mechanism. The drives can be integrated well into the standard belt conveyors in sizes 20 – 40, 30 – 60 and 40 – 80 (installation height – installation/belt width in mm). Wider conveyors too, such as the 40 – 120 and 40 – 160 versions, are available, as are special solutions based on the same principle, such as ascending conveyors. The motors are supplied with 24 V. The belts can be operated at different speeds thanks to variable gear reduction. For special cases requiring infinitely variable speeds with very sensitive adjustment, there is an additional speed controller and, for the variants with EC servomotor, the speed control comes as standard. All moving parts of the belt conveyors and of the drive are completely enclosed, with lifetime lubrication, thus ensuring maintenance-free operation.
Compact Drive Power
The drive is key in determining the reliability of the belt conveyor. Micro drives, however, follow their own rules. Drawing on their many years of experience, the FAULHABER specialists are able to supply drive units that are optimized down to the last detail. The drive unit comprises inexpensive, durable graphite-commutated coreless DC motors that can be controlled easily in combination with planetary gears. Particularly with micro drives, it is the special design that is key to a long service life. High input speeds and a high output torque make special demands on materials, tooth geometry, bearing positions and above all, on the lubricant. When properly dimensioned, these drives provide many years of maintenance-free service.
If something even smaller is required, or if continuous operation is a priority, then the preferred option is brushless dc motors (BLDC). They are not subject to any brush wear, can be mass-produced all the way down to 1.9 mm diameter, and can be equipped with gears with a diameter corresponding to the motor. The drive unit is either integrated into the motors or is external and, as with coreless dc motors, affords sensitive, infinitely variable control of speed and torque.
FAULHABER supplies state of the art micro drives in a vast array of designs for any application. If the drive specialist is involved in project development from the outset, optimized, perfectly adapted solutions can be implemented. In addition to standard drives, tailor-made and modified specialist solutions can be created at a reasonable price if planning begins early on.
To learn more about robotic and industrial automation applications and the micro motors which power them, please feel free to contact one of our application engineers, or explore the MICROMO Motion System Selector to view products and configuration options.