Special Rear Flange
Due to the flexible manufacturing, Nanotec offers its customers the special flange corresponding to the application and load with the appropriate bearings and tolerances. The new special flanges are manufactured with the permissible geometrical variation and tolerance classes with regard to roundness, conicity, angularity, axial run-out, concentrity on the basis of a 3D drawing, measured with a 3D Zeiss measuring machine and then sent to the customer for approval by means of an initial sample report. Then all relevant data, including the volume of lubricant quantity or special bearings for vacuum, currently 10 to the power of 5 bar, are also recorded in the drawing.
Special Front Flange
Customer-specific front flanges offer individual mounting options as well as constructions that can be integrated in existing structures.
Until now, it was only possible to carry out mounting on the front for the sizes ST3818, ST4209 and ST4118. Through a special flange, mounting on the back can now be realized that proves favorable in some applications.
Mounting Flange with Metric Thread
For easy mounting we also offer mounting flanges with metric threads. The SC4118 and SC6018 series are already equipped with mounting flanges M3 respectively M5.
For other motors flanges are available upon request.
Special Motor Windings
In the case of continuous applications and applications operated with fixed speeds such as agitators, conveyor belt, pumps and similar, for example, a drive solution that is as energy efficient as possible should be selected to keep the power losses and the module outlay as low as possible. Depending on the external mechanically power required Pmech = Md * n * / 30 - ( e.g. 0.15 Nm * 300 rpm * / 30 = 4.5W ), an equivalent electrical power is required for this with Pel = I² * R or U * I ( 0.5² A * 19 Ohm = 4.5 W (= ST4118M0706).
All Nanotec stepper motors and BLDC motors have been measured on a calibrated torque test stand in regard to torque versus speed and illustrated in the catalog as well as on the web. The customer can then obtain the requested data relatively easily from the torque characteristics or calculate them with the motor assistant. In the example shown above, the motor size ST4118M0906 ( = 0.64² * 11.4 = 0.57W) would fulfill the requested power with a safety of approx. 20% while the ST4118M0706 would work at the requested power limit. Nanotec offers different windings with the same construction length in order to provide the customer with as good an energy compromise as possible for his starting speed. In the example given above, for example, the ST4118M0408 would probably draw the least current and, hence, dissipate the lowest power with 24 V * 0.28 A = 6.7 W (via PWM control, very roughly approx. 3.4 W) where the winding with 60 Ohm would not provide the requested power due to the Md characteristics. By contrast, the ST4118M1206 motor with the same construction volume, a resistance of 6.2 Ohm and a current of 0.85 A dissipates 24 V*0.85 A = 20 W (average value approx. 10 W) so that the power dissipation compared to the ST4118M0904 with 24 V*0.64 = 15.2 W (average value approx. 7.6 W) is approx. 30% higher.
To generate the lowest power dissipation in the respective application, in addition to the windings listed in the catalog Nanotec offers another series of customer-specific windings to its customers. This flexible winding construction ensures that the customer can always realize the nowadays more important objective of energy savings in its new devices. In addition to lower power dissipation, the temperature increase is lower, hence the expected service life is higher and the electronic components of the control can be kept smaller as well.
In some customer-specific motors of the ST4118.. and ST5918… series high-temperature windings, winding formers and paint coatings with the insulation class F = 155°C have already been constructed. By contrast, further material tests are required in insulation class H = 180 °C, primarily with regard to winding formers. Compared to standard motors, the torque in high-temperature motors drops by approx. 5-10%. Higher temperatures can generally be reached with shorter power-up time or motors with larger construction type which also generate proportionally lower inherent temperature rises with lower nominal current and, hence, can be deployed for higher ambient temperatures. High temperature windings are sometimes also used in vacuum motors.
All standard ball bearings of Nanotec motors have an integrated ZZ seal which, together with the shoulder of the inner bearing, forms an active gap seal and makes it difficult for dirt particles to penetrate and prevents emergence of the lubricant. The cover plates are made of non rusting steel and do not cause any increase in torque or have any influence on the highest admissible speed compared to open ball bearings.
For greater sealing requirements, the material selection regarding chemical resistance, high and low temperatures, low and high contact pressure and circumferential speed, vacuum, Rockwell hardness, special coatings with regard to FDA conformity for beverage and foodstuff applications etc. is decisive.
Whereas the most different forms and constructions, such as special lip profiles for the optimization of driving forces, O-rings with different tolerance classes and cross-section diameter, radial seals, radial shaft sealing rings, face seal, V-rings with chamfered sealing lip, elastically supported PTFE seals (with highly stress-resistant plastic compound and an embedded spring of corrosion-proof stainless steel), as well as also RS, 2RS seals, VS seals, RZ seals are specified by the respective applications. Through the integrated sealing construction, together with our customers we can realize a wide variety of different sealing solutions with even the smallest clearances.
Special Ball Bearing
All Nanotec stepper motors and BLDC motors of the ST.. and DB.. series are equipped with double bearings (with lifetime lubrication and a service temperature of -40°C - + 130°C at low coefficients of friction of approx. 0.001-0.002) of high-quality grooved ball bearings that offer a high static and dynamic load capacity, wear life, range of temperature and reliability. The external track is usually connected with the stationary machine part (motor housing) and the internal track connected with the machine part (motor axis/rotor).
In the Nanotec motors, the thrust bearing is on the shaft output side (A-side) and takes over the radial support and the axial guiding in both directions at the same time) whereas the non-locating bearing on the B-side only takes over the radial support and allows an axial shift through the integrated equalizing shim washer or wave spring washer. For all standard motors, the maximum admissible radial and axial forces are specified in the datasheet.
In order to transmit higher radial forces, space saving bearings with different inside and outside diameters are also deployed. For applications with higher axial forces (such as helically toothed pinions or spindle drives), integrated angular contact ball bearings ensure the necessary safety. The linear bearing preload reduces the axial play between the bearing balls and the internal and external rings of the bearings, and above all also reduces the danger of damage to the bearings that are caused by the forces of vibration due to eccentric loads or linear deformations of the shaft that occur as well as thermal deformations, bracings and deformations of the supplementary parts to be mounted.
Relative motions between bearing rings, shafts and casings are avoided by the use of appropriate sizes. The rigid fit is, therefore, also necessary so that the relatively thin seal support rings do not bend under the load, but are supported around their entire circumference.
The ZZ covers used in the standard bearing offer a certain protection against gross contamination and escape of grease whereas the grease lubrication used produces a low coefficient of friction at a temperature of -20 °C to + 130 °C and ensures maintenance-free operation with high service life (20,000 h for a standard motor).
In addition to the standard bearings and depending on the wide range of different applications, Nanotec also offers a wide range of special bearings made of special materials or chrome-alloyed special steels with different outside and inside diameters, with contacting, non contacting and contact-free covers and seals made of plated steel sheet, steel-reinforced NBR and high temperature sealing with optimized bearing clearance and higher precision classes to DIN620T2.
Lubricants / Greases: Special applications such as oscillating movements with a restricted rotation angle range < 90° during continuous running (the balls no longer carry out whole revolutions of 360° and have, therefore, to be provided with a special grease), the use of special lubricants at low or high temperatures or also food-grade special lubricants require detailed knowledge of tribological requirements.
By contrast, momentary operation, e.g. on start-up, is innocuous as the frictional heat generated raises the bearing temperature into the green operating temperature range. To achieve a running friction that is as low as possible, an operating life that is as long as possible and a speed that is as high as possible, a grease distribution and run-in must be carried out. This helps to reduce the initially occurring higher friction from flexing and can have a positively effect on the operating time as well as the speed capacity. We will test this and incoorporate this in the design according to your applications.
Linear actuator with integrated limit switches
For this application, the motor sits in the middle of two symmetrical push rods. Therefore, the spindle was put on the rear side, also with a thread, where the push rod is mounted. We attached two hall sensors as limit switches on top side of the linear slide lock. They are triggered by a magnet traveling along on the spindle.
Valve drive for liquid chromatography
Due to the limited installation dimensions in the new customer application, only a maximum edge lenght of 28 mm for the motor was possible. espite this, a torque of 0,55 Nm had to be reached, which until that point had been achieved only with a motor with an edge lenght of 40 mm. As a result, a planetary gear with a gear reduction ratio of 19:1 became necessary. The NOE1 encoder was installed on the gearbox' output shaft in order to be able to position with 100% accuracy despite backlash from the gearbox. Using quadrature evaluation, a resolution of 0.045° can be reproducibly achieved this way.