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antriebstechnik 11/2019

antriebstechnik 11/2019

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FORSCHUNG UND ENTWICKLUNG 03 Selection of available dresser/threaded grinding wheel combinations. First step: Selection of best fitting dresser. Second step: Due to a small change of the dresser wheel gap (AL *eff ), the requested tip relief amount (C αa ) can be achieved If the production department requests a change to the gear geometry, the design process often must be restarted, making the process time inefficient. Instead, an often-repeated request from production departments is to integrate certain manufacturing experience into the design process. Frequently designers are not intimate with manufacturing processes and so it is beneficial for him or her to have access to simple manufacturing information within their design software. This can, for example, determine if an intended manufacturing process is feasible or not. 2. SELECTION OF AVAILABLE TOOLS DURING THE GEAR DESIGN PROCESS 2.1. CHOICE OF HOBS OR GEAR SHAPING CUTTERS For companies producing special gear boxes in single-unit or in small batches, costs can be reduced if existing tools such as hobs or shaper cutters can be reused. The design software can present a list of available tools when the gear geometry (reference profile) is defined. Such a task is simple to achieve if it is possible to add a list of available tools (figure 01) in the gear software. A more advanced option is the integration of a list with available tools into a macro geometry variant generator. A tool called ‘Finesizing’ in Kisssoft [2] permits, while keeping the main parameters such as center distance and face width fixed, for a given gear reduction, iterating over a range of normal modules, pressure and helix angles, with different combinations of number of teeth and profile shift coefficients. If the option ‘use only available tools’ is activated only solutions using existing tools are displayed (figure 02). 2.2. USE OF AVAILABLE DRESSER / THREADED GRINDING WHEEL COMBINATIONS Another efficient manufacturing process is Threaded Wheel Grinding which is used normally as a finishing process of gears. For dressing the grinding wheel, an expensive dresser is required. For a gear designer, when working on a new gear set likely with profile modifications, it would be helpful to get a list of existing grinding tools/dressers with the resulting profile modifications that will be produced when they are used for a new gear geometry. With this information available, an existing dresser can possibly be reused for a new project. As displayed in figure 03, in the first step all available dresser/grinding wheel combinations are displayed with the amount (C αa ) and length (Lc αa ) of tip relief generated. After selecting the best fitting dresser, the tip relief amount can be further varied in the second step by the adaptation of the dresser wheel gap (AL *eff ). 144 antriebstechnik 2019/11 www.antriebstechnik.de

FORSCHUNG UND ENTWICKLUNG 04 On the left: Power Skiving Process, on the right: Visualization in Kisssoft [2] 05 Requested data for the check, if Power Skiving is applicable 3. CHECKING IF ECONOMIC PRODUCTION METHODS ARE APPLICABLE To design cost-competitive products, it is worthwhile to make production method decisions early. Many different methods such as Grinding, Shaping, Honing, Broaching, etc. can be considered and evaluated. In this paper, the relatively new manufacturing method, Power Skiving, is used to explain the integration of manufacturing restrictions into the design process. 3.1. POWER SKIVING The Power Skiving process is a breakthrough in the production of gears [7]. It is several times faster than gear shaping and much more flexible than gear broaching. Power Skiving is setting ever-higher standards in the machining of internal gears and/or gears with critical interfering contours (figure 04). Originally intended as a competitive alternative to gear shaping, and in some cases to broaching, for small to medium-sized nonhardened cylindrical gears, its range of application has expanded significantly. Today, we find Power Skiving solutions for soft and hard finishing of internal and external gears, for machining shafts and worms, as well as special profiles such as cycloidal gears for robot applications. Most gear cutting applications are placed somewhere between distinct production worlds: highly efficient mass production and flexible manufacturing of smaller, rapidly changing lots. Depending www.antriebstechnik.de antriebstechnik 2019/11 145