FEATURE MECHANICAL COMPONENTS
Depending on the version, the new heavy-duty versions of the welding system positioners have to be able to handle two, three or five tons
in which very fast positioning movements are achieved with high payloads; and the eccentrically connected drive allows more reduction ratios than with centred mounting, often eliminating the need for upstream planetary gears. RD-C gear heads are based on RV-C
installation kits with a cycloid design. They feature a large through-bore with a main support bearing, and this hollow shaft, which has a diameter of up to 150mm, can be used for shafts, lasers or – as in the case of Panasonic – cables and wires.
PRECISION GEARS HEAD into the robotic welding market
Needing precision gear heads for a new range of welding robots with heavy-duty rotary/tilt tables, the design engineers at Panasonic Robot and Welding Systems Europe turned to Nabtesco for the solution
F
or many years, Panasonic has selected precision gears from Nabtesco when
building its robots. So, when Panasonic Robot and Welding Systems Europe in Neuss began to develop a new product – welding robots with heavy-duty rotary/tilt tables – the design engineers once again turned to the company when it needed gear heads. While the standard positioners for
welding systems can support payloads of up to one ton, the new heavy-duty versions have to be able to handle a payload of two, three or five tons, depending on the version. In addition, the use of Panasonic servo motors was a prerequisite. Following research and consultation, area manager, Sergio Maeda, decided on gear heads from the Nabtesco RD-C series. The RD-C gear heads drive the
horizontal rotary axes of the welding tables, for millimetre-precise access to all welding points on this axis without having to change the clamping setup for the part, explains the company. Furthermore, the horizontal rotation/tilting is also achieved by means of the gear heads.
MEETING THE DEMANDS To meet the application demands, a number of specifications were required: • Gear head with a hollow shaft for cables • Bearings with high impact resistance for loading/unloading components
• Direct adaptation of the Panasonic servo motor
• Rigidity and precision for positioning accuracy of ±0.05mm at r = 250mm
18 MARCH 2014 | DESIGN SOLUTIONS
• Long service life • Straightforward design of the positioners
• Optimal cost-effectiveness ratio. The modular design of the
precision gears enable their use in diverse applications, not only in rotary positioners. Of additional benefit, they are ready-to-install, pre-lubricated and have a calculated service life of 6,000 hours. An adapter for the most common servo motors is mounted on the motor flange. Being rigid in construction and high
precision, they are suitable for applications The gear heads also have a high payload
capacity, which can absorb impacts of up to five times the rated load torque, and a high torsional rigidity ensures that the gear meets the required standards for robustness. The high precision is guaranteed by the low backlash of less than one angular minute and the compact design is achieved with high reduction ratios and high
torques combined with a small gear volume. As no additional bearing
is need on the mounting side, construction and assembly time, as
Their high payload capacity allows the gear heads to absorb impacts up to five times the rated torque
well as overall cost, can be reduced. The gear heads have been in use on heavy-duty positioners since the end of 2011 and have resulted in high reliability.
Nabtesco
www.nabtescomotioncontrol.com Enter 211
SRBS CUT DOWNTIME IN THE STEEL INDUSTRY
In the steel industry, keeping the smelter running is crucial to maintaining the production process. So if a fan responsible for the control of the temperature and airflow within the smelter suffers a bearing failure, the downtime costs can be considerable. At one UK based steel plant, the original equipment consisted of a standard Plummer block bearing arrangement; but, in the event of a failure, it would take in excess of 14 hours to change the two fan bearings. Having assessed the installation, Revolvo engineers were able to specify a suitable SRB split roller bearing which would fit within the existing bearings dimensional constraints. The proposed solution offered a number of benefits including superior
sealing properties, improved performance, and the ability for bearing inspections to be undertaken in-situ. In addition, as the SRB bearing is totally split to the shaft, it can be removed and replaced in around 90% less time and without the need for ancillary equipment. SRBs allow the shaft to be supported by the lower section of the bearing
and housing, whilst the upper section of the housing and bearing outer race can be removed. Inspection of the bearing trackway, cage and rollers and lubricant is fast and simple, without the need to remove drives or lift the shaft. This intrinsic feature is especially valuable regarding large rotating machines, where sheer weight and size can be a barrier to fast and effective servicing. The new bearings have been operating successfully for over 12 months.
Revolvo
www.revolvo.com Enter 212
/ DESIGNSOLUTIONS
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52