Need an account? Click here to sign up. Download Free PDF. Parametric Design Of Spur Gear. Sumit Dharmarao. A short summary of this paper. Mulkutkar Mohanlal M. In the world of 3D modeling, one term that comes up frequently is parametric sketching. Parametric sketching, the basis for 3D modeling in many design software, is a type of sketching that uses parameters and equations to drive geometry. Parametric modeling captures the design intent with geometric relationships so if a designer changes one dimension, the entire model updates to accommodate the new parameter.
This technology greatly reduces the amount of time designers spend modifying designs and helps get designs to manufacturing faster. It allows any element of the model to be changed and automatically. The parametric design helps us to quick modification of product drawings which results in reducing lead time. For example, holes are a certain distance apart, or an edge is half as long as another edge, and so forth. Parametric sketching provides a method to maintain and take advantage of these relationships in your sketches and in your parts.
Designers use parameters, equations, dimensions, sketch constraints, and construction geometry to define these relationships. For example, placing a dimension between two points creates a relationship between those two points. Because of this relationship, the two points are always that distance apart, even if one of the points is moved.
This is a simple example of design intent. Another one is sketch constraints. For example, a rectangular feature is centered on a cylindrical feature. For example, you specify the length of a rectangle as being twice the width. The easier it is to move from one iteration to another, the more design time and overhead are reduced, getting your design to production faster.
Another one is before you spend time on modeling, sketching mechanisms provide testing and confirmation of their intended range of motion. Individual elements of a mechanism are constrained together and dragged, effecting change on adjacent members just as they would in the model or with real parts. In the following figures, a crank-operated accordion system can be analyzed easily by dragging the circle crank.
If it is determined that this mechanism is insufficient to solve certain design criteria, it is simple to modify it or start from scratch with a new concept. Effect of slipping is reduce Velocity Ratio VR of system. In precision machines, in which definite VR is of importance the only positive drive is by Gears or Toothed Wheels.
Gearing is one of the most effective methods for transmitting power and rotary motion from the source to its application with or without change of speed or direction. This paper analyses the bending stresses characteristics of an involute spur gear tooth under static loading conditions. The stresses at the tooth root are evaluated analytically using existing theoretical models.
The theoretical and FEM results are compared. The results obtained theoretically are in good agreement with those obtained from software. Also an attempt is made to introduce Stress and displacement characteristics of tooth under dynamic loading conditions. International Journal of Mechanical Engineering and Technology, 7 5 , , pp. Because of the high degree of reliability and compactness gears dominates the field of mechanical power transmission.
Gearbox is used to convert the input provided by a prime mover into an output required by end application. Due to increasing demand for quiet and long-term power transmission in machines, vehicles, elevators and generators, people are looking for a more precise analysis method of the gear systems.
It requires the better analysis methods for designing highly loaded spur gears for power transmission systems that are both strong and quiet. Due to development of computers people are using numerical approach for the analysis purpose as it can give more accurate analysis results. The finite element method is capable of providing information on contact and bending stresses in gears, along with transmission errors, which can be done easily in ANSYS software. Gear analysis in the past was done by using analytical methods which requires complicated calculations.
Now with the use of FEA we can calculate the bending stresses in the gear tooth for given loading condition and we can compare the FEA results with existing models to decide the accuracy. Also static as well as dynamic, both loading conditions of gear can be easily analyzed in Ansys which is not the case with Analytical method. Any problem can be solved by following same procedure. Question The Following data is given for a spur gear pair made of steel and transmitting 5KW power from an electric motor running at rpm to a machine: No.
Hence it is necessary to design the gear for bending. Even today, the Lewis equation is considered as the basic equation in the design of gears [1]. This parabola shown by dotted line is a beam of uniform strength. In the current analysis of spur gear we follow the Lewis assumptions and equation.
So we directly find the deflection of the parabolic teeth with minor errors with actual deflection [2, 3]. The theory applies to both linear and rotational deflections. Analytical Results 3. Using basic values for various parameters. Analysis by using Ansys 3. Ansys Procedure The entire analysis is done on the single gear tooth in Ansys For that purpose we use the following procedure, 3. Do not consider the fillet radius as assumed by Lewis.
Take element type as beam. Take 25 nodes equidistantly on length equals to tooth height and create different sections of calculated dimensions length and breadth. Then create elements at nodes of corresponding element attribute. One end of tooth is fixed and at other end tangential load of N approx. All boundary conditions are applied on nodes. Plotting Stress and Deflection Graphs For end conditions. Comparison of Results Stress Sr. Ansys Deflection mm Analytical De flection mm 1.
So these FEA models are good enough for stress analysis of spur gear teeth in static condition 4. Introduction to Dynamic Analysis Dynamic load is defined as the load which varies in magnitude, direction or point of application with respect to time.
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