Solidworks CAD Pulley System
Cad Rep
Parametrisation
Some of the important parameters that I created and then used in my design table and also in the calculations below are as follows:
Shaft Radius= Shaft Diameter/2
Gear Circumference= No. of teeth x 10mm
Flange Diameter= (2 x Gear Radius) + 10
Hub Diameter= Shaft Diameter x 2
‘Cut for Shaft’ diameter= Shaft Diameter
Hole Diameter= Shaft Diameter
Calculations
The first calculation was to calculate the Gear Radius (r) using the information provided:
The appropriate belt width was then determined; this was done using the torsion of the belt (including a factor of safety 1.5). The equation for the torsion (including the FOS) is
The available belt widths were 16, 25 and 32 mm. The belt has a loading capacity of 60N/mm, which is combined with torsion in the equation to find the belt width:
The shaft hole (and so size of shaft) is determined by the shear strength of the fit of the pulley onto the shaft which is 186 MPa. There are three shaft diameters (10, 15 and 20) and the correct one is found by the equation
Weight Saving Design Rationale
Creating four straight material saving holes seemed like a simple and relatively effective way of achieving the objective of reducing volume also it helped maintain the axial symmetry required by the model specifications. Making the edges of the cut sections circular made sure no material was being left unnecessarily. In addition I filleted both sides of the flanges in order to reduce volume. I made sure that the hub wasn’t thicker than necessary and flanges only 1mm thick, both these steps were taken to reduce the volume.
Modelling Process
My first step was to draw a single tooth with and arc on either side. This was smart dimensioned to the correct shape and then extruded. The radius is the main smart dimension to be created as this is required for the design table. It is important to extrude before circular patterning as it doesn’t work if it is patterned first. Next the edges
Parametrisation
Some of the important parameters that I created and then used in my design table and also in the calculations below are as follows:
Shaft Radius= Shaft Diameter/2
Gear Circumference= No. of teeth x 10mm
Flange Diameter= (2 x Gear Radius) + 10
Hub Diameter= Shaft Diameter x 2
‘Cut for Shaft’ diameter= Shaft Diameter
Hole Diameter= Shaft Diameter
Calculations
The first calculation was to calculate the Gear Radius (r) using the information provided:
The appropriate belt width was then determined; this was done using the torsion of the belt (including a factor of safety 1.5). The equation for the torsion (including the FOS) is
The available belt widths were 16, 25 and 32 mm. The belt has a loading capacity of 60N/mm, which is combined with torsion in the equation to find the belt width:
The shaft hole (and so size of shaft) is determined by the shear strength of the fit of the pulley onto the shaft which is 186 MPa. There are three shaft diameters (10, 15 and 20) and the correct one is found by the equation
Weight Saving Design Rationale
Creating four straight material saving holes seemed like a simple and relatively effective way of achieving the objective of reducing volume also it helped maintain the axial symmetry required by the model specifications. Making the edges of the cut sections circular made sure no material was being left unnecessarily. In addition I filleted both sides of the flanges in order to reduce volume. I made sure that the hub wasn’t thicker than necessary and flanges only 1mm thick, both these steps were taken to reduce the volume.
Modelling Process
My first step was to draw a single tooth with and arc on either side. This was smart dimensioned to the correct shape and then extruded. The radius is the main smart dimension to be created as this is required for the design table. It is important to extrude before circular patterning as it doesn’t work if it is patterned first. Next the edges