COT Tubes & Clips - Wiring Harness Design
Wiring Harness Routing & Packaging Rules
In this challenge, we are first going to define a mechanical cad component electrically by setting up the geometrical parameters and then using the "Electrical Part Design" workbench we will define the electrical support.
The first given model in this challenge is a "P Clamp" which we need to define as support.
The steps followed in defining a mechanical part as electrical support is as follows,
1. Download & open the 3D CAD data (P camp) in CATIA V5.
2. Define the Geometrical Parameters to it.
3. Define part as support.
4. Define Entry Point & Plane.
5. Define Exit Point & Plane.
In order to set the geometrical parameters for defining the electrical support, we need to create an Entry Point & Plane, Exit Point & Plane and a Base Plane as shown in the figure.
Once all the points & planes are created, we are ready to define this part electrically.
Click on "Define Support Part" in the electrical part design workbench and select the entry point & plane under the first plane definition. Similarly, Select the exit plane in the second plane definition & base plane in the base plane definition respectively.
While defining the part as electrical support an engineer has a provision of defining two entry sides hence we need to define the support again.
Here once we click on define support again, the exit plane is already selected in the plane 2 definition. This is because we have selected that plane as an entry plane previously, thus leaving us with only one entry side left to define. Also, the points will be hidden once we completed defining the support.
The part is now completely defined as an electrical part. The part can now be saved under the catalogue for reference which helps the engineer to avoid creating it again during the routing process.
Backshell
Backshells are plastic moulded parts used at the wire entry side of connectors either for protection or to improve the aesthetics of the harness.
These are not mandatory parts of a wiring harness and are always optional. It is mainly driven by the cost & requirement of the wiring harness engineer.
Defining Backshell is pretty simple. Ideally, we first need to set up the geometrical parameters that we use to do for all electrical components.
Once parameters are set define this part in Electrical Part Workbench using the command "Define Back Shell".
Now define the backshell connection point using the point & axis created at the mating side of the shell.
Then define the bundle connection point using the point and surface located at the entry side of the bundle.
A catalogue for the same can be created for reference.
Corrugated Tubes
Corrugated Tubes, Convolutes, Sleeves and many other types of coverings are used to protect the wiring harness. The graphical representation of these coverings is applied on bundles.
These tubes can easily be created in CATIA using Electrical Part Design workbench by giving appropriate dimensions to them. Create a new part, select define protection covering and click on the part body or file name under the model tree.
The dimensions that are required to create COT Tubes are Inner & Outer dia, Thickness & bend radius.
The bend radius is decided based on the flexibility of the tube. Generally, the bend radius will be 1.5 times the outer dia of the tube.
Depending on the bundle dia the COT outer dia is decided. The dia for the Tubes must be greater or equal to the bundle dia.
In this challenge, we have created multiple tubes with different dimensions and saved them in a catalogue under the COT Tubes family.
Corrugated Tubes or simply called as COT Tubes are created & saved in a catalogue. It is necessary for an engineer to save the tubes in a catalogue in order to use them during the harness process.
The length for the tubes are not defined & it is not even required. The software will automatically define the length of it based on the bundle length during the application of the wiring harness.