Machine designers can now design complex bearing arrangements and analyse bearing loads more quickly without having to master complex software programs thanks to SKF’s software and equipment technology advancements.
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Bearing and seal manufacturer SKF has developed software to design its products more effectively. The software combines an intuitive interface with powerful simulation to produce designs that can be validated quickly and effectively.
One way that SKF has done this is to take in-house software called SimPro Expert – which it uses to develop and design highly complex bearing arrangements – and make it more user-friendly for customers.
SimPro Expert can be used to model an entire gearbox, in order to see the influence of one shaft on another; to determine the supporting properties of the housing; and to understand the detailed bearing behaviour for the given conditions.
“SKF application engineers know the SimPro Expert software very well. You need to be a relatively frequent user and have a good level of bearing knowledge to get the most from it,” says Francisco Serrano, manager for product line engineering tools at SKF.
Although design engineers within OEM companies tend to have a solid knowledge of bearings, many would not consider themselves to be ‘experts’. SKF application engineers constantly design bearing arrangements, which is not necessarily the case with in-house OEM engineers, who can go long periods or intervals between bearing projects. They also cannot devote their time and effort to learning complex simulation software in detail.
It is for this reason that SKF has developed SimPro Quick – a stripped-down version of its more specialised bearing design programs.
SimPro Quick has the same core as more advanced products such as SimPro Expert and SimPro Spindle. It retains many of their innovative features, but it is far easier to use. While customers were demanding more advanced analysis of their bearing designs, they wanted to be able to do it in an intuitive way, using tools that were not excessively complex. SimPro Quick is a single-shaft bearing simulation tool developed to evaluate the design of bearing arrangements and their field performance quickly, based on relevant application requirements and conditions.
Catalogue link
A key feature of the software is that it ties in with SKF’s new online Roller Bearing Catalogue – which is a live database of products. This means that anything incorporated into a design will be a current product.
“If we were using a paper catalogue, it would be out of date on the day it was printed,” says Serrano. “Now, with the software, it’s live – so any product that is selected will be available and up to date.
“The link with the live database not only offers the latest products, but also allows them to be selected according to specific criteria – such as, high availability.”
Model building
SimPro Quick builds a complete model in three steps: components; boundaries; lubrication and clearance.
In the first stage, the model is built using common components such as bearings, springs and spacers. These are incorporated into the model by ‘dragging-and-dropping’ them onto the shaft. Bearing types can be searched based on dimension, designation as well as whether it is a ‘popular item’. Other elements such as gears can also be ‘dragged’ onto the shaft.
The second stage is to set applicable boundary conditions. Factors such as shaft rotational speed, radial and axial forces and gravity can be added to the model. Force, power input and moment are all applied using ‘drag-and-drop’, while other boundaries are added with an icon click.
The third stage is to apply the lubrication and fit conditions. SimPro Quick allows the user to define the lubrication method and type, oil viscosity and contamination level. All lubrication properties affect outputs, such as relubrication interval for greases and bearing friction.
Once these steps have been completed, SimPro Quick carries out an analysis of the model. Here, users can run a single (data set) analysis or several conditions at once (load cycle analysis) based on defined operating boundaries. A time weight portion can be applied to each step, which is useful when determining bearing life over several different operating conditions.
The output of the analysis includes data tables and visuals that enable the user to create a preferred template set-up for the report. These might show factors such as bearing loads, operating internal clearances, friction, misalignment, deflection and SKF rating life.
For now, all modelling is done within the program itself. SKF has added a CAD import functionality, which allows users to import a CAD design into SimPro Quick. Other features include visual plots and animations, including a shaft deflection plot.
“In one case, a manufacturer of high-end textile machinery used SimPro Quick to increase the speed and accuracy with which it designed bearing arrangements. Running accuracy of the bearings was critical to the overall performance. Using SKF SimPro Quick helped the company speed up its design process, while evaluating an optimal bearing arrangement without external help.
“This was due in part to the user-friendliness of the software, combined with its advanced analysis capabilities. The embedded e-Learning module made an intuitive piece of software even easier to understand, allowing the user to quickly start modelling relevant bearing arrangements,” says Serrano.
Load sensing bearings
Software isn’t the only area where SKF is demonstrating digital innovation. Lars Kahlman, senior applications expert at SKF’s Drives Competence Center in Sweden, describes the work SKF is doing in the pumps and compressors department.
Designers can now accelerate the design cycle by analysing bearing loads quickly and accurately with the addition of fibre optic based load sensing bearings for pumps and compressors.
“SKF has released the world’s first commercial load sensing bearing based on its proprietary fibre optic sensing technology; a technology, which is part of a long term strategic technical product development,” says Kahlman. “Similar to the SimPro Quick technology, the SKF Load Sensing Bearing for pumps and compressors takes the guesswork out of product development.”
According to Kahlman the product is helping to speed up the design and verification process, by giving instant access to a variety of bearing data. This includes for example axial versus radial loads, polar lots of the bearing´s internal strain field, strain spectra, load directions, speed of rotations and temperature.
The first product streamlines the creation of rotating products such as pumps, using angular contact ball bearings. In it, SKF enables real-time measurement of bearing loads using fibre optic sensing.
The bearings, which are interchangeable with conventional bearings, offer several benefits to designers and test engineers, including optimised design, lower development costs, shorter design cycle and the ability to digitalise the design and verification process.
OEMs and end-users can use the tool when testing and installing new equipment to check that the correct load and lubrication requirements have been defined and are not exceeded in the real installation.
“Understanding bearing loads is essential in the design of rotating equipment such as pumps.” explains Kahlman.
“SKF has, through extensive testing campaigns and simulations, developed algorithms that make the technology really accurate and robust. Because it takes accurate strain measurements directly within the bearing, our Load Sensing Bearing provides access to data that until now has been difficult to access.
“The new sensing bearings are safe to use in hazardous environments as signal data is transferred at high-speeds by low power in optical fibre rather than as electrical signals, making the system immune to electromagnetic fields. It also enables robust remote monitoring where wireless technology cannot be used as the optical fibres can transmit signals over very long distances,” he concludes.
Customers can access SimPro Quick through a local SKF contact to request a license, or by registering through SKF’s website – after which the request will be passed on to a local SKF representative.