The following example is typical of an automobile engine accessory drive belt system. The system has several pulleys and idlers, connected by a serpentine belt.
Create an assembly sketch. Use circles to represent the outer rims of the pulleys. Use tangent lines between the circles to represent the serpentine belt. Dimension the size and location of each pulley.
For each circle in the sketch, insert a new part, sketch a circle, add a Coradial relation with the corresponding circle in the layout sketch, then extrude the sketch to create a pulley. Add other features to the pulley parts as needed.
Alternatively, create a sketch block for
each circle in the sketch, then in the FeatureManager design tree, right-click
the sketch and select Create
Assembly from Layout Sketch. This creates a part document for
each pulley, which you can edit to add other features as needed.
Using the layout sketch as a guide, create the belt around the pulleys as another new part.
|
|
|
You can change the location or the size of the pulleys by editing the layout sketch.
The assembly now consists of a belt and a set of pulleys whose locations and sizes are driven by the layout sketch. The advantage of this type of design is clear when you have to make changes to the design.
For example, working in the layout sketch, you can:
Rearrange the pulleys so that a slipping pulley has more of its surface covered by the belt.
Make a driven pulley larger so less torque is required to turn it.
Drag the pulleys and belt to dynamically experiment with different locations.
Set an angle dimension to specify how much of each pulley must be covered by the belt.
When you exit the layout sketch, the assembly and the parts are updated.
|
|
|
If you designed this assembly without a layout sketch, you would need to change many dimensions, or move components in the assembly, then rebuild each time.
The layout sketch does not have to be the master plan for a design. If you had a model of an engine with some fixed pulley locations, you could make the circles in the layout sketch coincident with the known locations of the pulleys in the model. You would still have the freedom to drag the other pulleys to different locations, and the assembly would update automatically when you made changes.
