Integrated motor-gearhead unit: Sophistication in engineering and design

The fascinating technological features inside and the elegant, coherent design of the outside provide optimal functionality when the RPM+ is installed and operated in a highly precise, dynamic, linear rack-and-pinion system.

A feast for the eyes - not just a treat for gourmets everywhere but also the recognition in recent years that an attractive, stylish design can significantly enhance many engineering products. In the meantime, there are actually a host of annual awards for elegantly packaged technology. For some time now, the WITTENSTEIN Group has collaborated with creative industrial design agencies with the aim of uniting beauty in shape, colour and surface texture with innovative engineering. The servo actuators in the TPM+, for example, set not only important technology standards but also visual benchmarks in their particular market segment. The newest eye-catcher whose design makes a consistent contribution to functional enhancements - generating added value for the application - is the RPM+ motor-gearhead unit. This novel solution is far more than simply a gearhead with a servo motor mounted to it: the combination of optimized inner workings crammed with rich engineering expertise and an integral concept greatly improves the performance and functionality of the entire mechatronics.

Optimal compactness meets intelligent integration

The RPM+ motor-gearhead unit was developed for linear drive solutions at the high end of the market, where characteristics such as improved tilting moments for more tilting and system rigidity, maximum positioning accuracy and exceptional ease of assembly are important application criteria. At the same time, there is probably no other actuator solution for rack-and-pinion applications that packs such top-quality engineering into such a high-quality design as the RPM+. The integration of the permanently excited servo motor illustrates this succinctly. The motor shaft is inserted directly into the gearhead, in other words the pinion is an integral element of the motor shaft with no intervening parts. This mechanical integration represents a first step towards reducing the overall length. The fact that the brake is now accommodated in the cavity underneath the winding head rather than at the back of the motor - saving another 10 to 15 mm - is a second convincing example. All in all, the RPM+ is 30% to 50% shorter than rival actuators boasting similar performance. The extremely rigid controlled system - and therefore optimal power transmission - of the actuator concept is a further advantage. Since the bearings are likewise designed for high radial forces, the RPM+ is often built a size smaller than the industry standard. The actuator is thus absolutely in line with the current trend towards downsizing: critical physical volume is economized both in the periphery behind the motor and at the gearhead - a benefit that makes a huge difference in many applications.

Added value through sophistication and elegance in design

The RPM+ proves in several ways that functionality and elegance are not necessarily a contradiction in terms. The design and colour of the housing transform the actuator into a real eye-catcher with high recognition value. The design concept simultaneously focuses on providing additional functionalities and hence added value for the application - especially when harsh operating conditions prevail. The smooth, rounded surface without any edges, for instance, prevents dirt deposits from forming on the actuator. The transition from the gearhead to the motor is coated with metallic blue, two-component paint. The fastening screws for the gearhead are cleverly concealed under covers reminiscent of teeth. The pinion has a stylish cap featuring the WITTENSTEIN logo which not only protects against dirt but also looks good and conveys the same impression of quality engineering as the seal cover at the output flange. The mechanical alpheno® interface with eight slotted holes permits optimal adjustment of the pinion and rack - with no need for a separate adjustment plate that would cost money and detract from the visual message.

Open for fine tuning to lead customer applications

The High Performance Linear System with the RPM+ actuator integrates the motor, gearhead, pinion and rack in an optimally controllable system. It is available in four different sizes with reduction ratios from 4 to 220 and various motor outputs up to 152 kW. In the "small" version, the RPM+ 040 with a reduction ratio of 4 and a size 155 air-cooled motor, the actuator is capable of accelerating a mass of 300 kg to a speed of 360 m/min in 0.3 seconds. The RPM+ 080 - the largest model currently available, with a size 220 water-cooled motor and a reduction ratio of 38.5 - accelerates a 200 ton mass to 40 m/min in an incredible 0.13 seconds. A positioning accuracy of only a few µm is achieved in each case. WITTENSTEIN's cooperation with lead customers in multiple industries will determine which specific motor, ratio and performance variants are manufactured in future with which characteristics. Thanks to its high degree of flexibility and modularity, the RPM+ also facilitates customized solutions for numerous tasks with complex integration requirements, for example in grinding, turning, portal milling, boring, laser, punching and pipe bending machines, water jet cutters, machining centres for wood-plastics compounds and basically any axes found in automation systems.

Integrated downsizing potential

High-tech in an elegant yet functional style, convincing performance characteristics for linear technology, engineering ideas that add real value - these are the hallmarks of our new RPM+ motor-gearhead unit in its role as an actuator for the High Performance Linear System. It unites higher tilting moments, feeding forces up to 112,000 N, maximum speeds up to 400 m/min and sophisticated integration and design concepts with enhanced functionality, intelligent assembly and considerable potential for downsizing linear drive systems. This mechatronic solution, with its overall efficiency exceeding 93%, shows how traditional drive engineering limits can be pushed back when system expertise in gearhead manufacturing, gearing technology and the design of motor-gearhead combinations is consolidated under one roof and condensed in a single product, which is then fine tuned to the customer's application and embellished with an elegant look that generates added functional benefits.

Rotary servo and linear actuator systems form the backbone of WITTENSTEIN motion control GmbH's product portfolio. Through their integration of the motor, gearhead and positioning mechanics as well as the control and sensor technology and software, these systems set the pace in the field of mechatronic rotary and linear actuators. They are used, amongst other things, in automation systems and special-purpose machines, handling systems, robotics, machine tools, production machinery and direct drive spindle systems for the woodworking industries.

Source: WITTENSTEIN motion control GmbH