FEATURE BEARINGS, SEALS & LINEAR MOTION Finding your bearings
In today’s fast-paced industrial world, rapid design processes and short time frames are vital to competing successfully and meeting new challenges. Design work can now be accelerated through a software solution that quickly identifies the optimum bearing arrangement – a fundamental requirement of all rotating equipment. Paul Dysiewicz, engineering manager at SKF, explains
A
new user-friendly software solution has been developed that enables the
designer to quickly identify the optimum bearing arrangement. SKF SimPro Quick is a simulation software tool that rapidly evaluates the design and performance of bearing arrangements. Taking into account the application’s requirements and the conditions under which bearings will be working, it enables a wide variety of bearing choices and other component combinations to be assessed. While the more powerful SKF SimPro
Expert tool is recommended for complex designs involving multiple shafts, SimPro Quick is ideal for single-shaft systems with multiple bearings. Not only is there is no need for several days of training in its use, but it enables designers to explore possibilities on their own, with access to the full and up-to- date bearing range. SKF’s knowledge is embedded in the software, so users can draw on it without having to stop and seek advice. However, if they do wish to consult the company or share a model for comment, SimPro Quick is seamlessly compatible with SimPro Expert and SKF’s in-house engineering software. The tool’s intuitive graphical
interface and bearing selection wizard offer an easy, stepwise, approach to carrying out analyses, creating complete simulation models, displaying results as 3D animations, and more. It also has guiding and warning features.
STEP 1 – SELECT COMPONENTS Choose a shaft and add bearings to it using the simple drag-and-drop function. A walkthrough process helps with bearing choice. In a similar way, with guidance provided, choose the gear type, geometry and power, then drag and drop onto the shaft. Add springs, if bearing pre-loading ability is required, and spacers if defined endplay values are to be set. The bearing catalogue indicates whether each product is a high-volume item, so designers can choose to specify only commonly used bearings if they wish.
STEP 2 – SET BOUNDARIES Set radial and axial forces, power input and moment load by dragging and dropping. Apply shaft rotational speed and gravity by clicking on icons. The ‘analysis variations’ part of the programme allows
SKF SimPro Quick is a simulation software tool that rapidly evaluates the design and performance of bearing arrangements
The tool’s intuitive graphical interface and bearing selection wizard offer an easy, stepwise, approach to carrying out analyses, creating complete simulation models, displaying results as 3D animations, and more
all boundaries to be altered, apart from gravity – for this, a separate method is provided for the study of applications in both horizontal and vertical positions.
STEP 3 – ADJUST LUBRICATION AND BEARING CLEARANCE Select a lubrication method, along with levels of oil viscosity and contamination. These factors have impacts in terms of relubrication interval, bearing friction and other outcomes. Finally, click on the bearing fit icon. This opens a sub-window for adjustment of shaft and housing fits, internal bearing clearance, and inner and outer ring temperatures, all of which affect bearing clearance in operation.
ANALYSIS, RESULTS AND OUTPUTS Once the model is complete, there are options to run a single data set analysis or to consider several conditions in a load cycle analysis based on defined operating boundaries. When examining bearing life under a range of different operating conditions, the option of providing a time weight portion for each step is useful. Output tables and calculations cover such factors as bearing load, loaded zone, gear force, operating bearing clearance, contact stress, friction, defect frequency, relubrication interval, grease life, misalignment, shaft deflection and rating life. Service life can be determined and expressed as basic rating life, modified reference rating life (according to ISO/TS 16281:2008) and SKF rating life. The tool goes further by providing warnings on conditions which may prevent bearings from achieving their expected lifespan. Plots and animations add extra detail and aid visualisation of results. 3D animation is especially valuable in investigating roller pressure distribution and the impact of boundary conditions on shaft and bearing movement. The conditions experienced by each
rolling element in a bearing can be studied by polar plotting of contact angle, contact deformation and contact load. Comparison of multiple plots can reveal issues such as heavy load concentration or an excessively high angle. A plot showing deflection along a shaft’s length under the given operating conditions can also identify issues of concern.
SKF
www.skf.com
SimPro Quick and SimPro Expert are part of a comprehensive set of SKF engineering tools developed to meet different designers’ needs. These include solutions for single bearing or bearing set selection and calculations, as well as a quick and advanced simulation tool for spindle applications. Solutions such as this enable design work to be accelerated, ensuring rapid design processes are combined with accurate bearing specification and increased competitiveness.
18 SEPTEMBER 2019 | DESIGN SOLUTIONS
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