Project 2

AIM- Route the Wiring harness on given Car Hatch and prepare a flatten view drawing in CATIA V5.

OBJECTIVE- The objective of this project is to route the wiring harness and prepare flatten-view drawing for the given car body hatch. All types of packaging rules and constraints have to be considered while routing the harness. Industry best practices should be implemented in the harness design. All necessary details like clearance/ clamping selection, harness fixing requirements, harness continuity should be provided in order to design the wiring harness.

Figure A - Given car body hatch or trunk door for which wiring harness has to be designed.

BACKGROUND, TECHNICAL SPECIFICATIONS, AND ASSUMPTIONS-

Below are the few references from the real-world which were considered while designing the wiring harness for this project

The wiring harness packaging rules and the industry best practices that have to be followed to complete this project are as follows:-

1. Easy manufacturing, installation, removal, and maintenance have to be considered while designing the wiring harness.

2. Routing through small structural holes or opening shall be avoided to minimize chaffing and handling during installation.

3. Avoid harness routing and clipping in the blind zone or hard to reach areas during harness assembly or in service.

4. Provide additional slack if needed according to the surrounding and harness bending requirement. For this project, the slack value between 1-5% is used.

5. It should be made sure that there is no case of fouling while designing the wiring harness in the CAD environment. Additional clips/ clamps may be used to avoid fouling.

6. Avoid harness routing near sharp edges or else provide protection over the harness.

7. Enough mounting equipment such as clips and clamps should be provided.

8. The branch length should be greater than 50mm.

9. The minimum distance between the clip to the branch point should be at least 25mm.

10. The minimum distance between the two branch points should be at least 50mm.

11. The wiring harness should be easy to assemble and easy to excess.

12. Clips/ clamps used for the wiring harness should be easily available in the market to avoid extra cost for custom mounting solutions.

The given car body hatch or trunk door has multiple areas of interest. The two taillights and the two license plate lights have to be wired and connected to the car electrical main system.

For these four lights, we will be using a Deutsch 2-pole connector. The car hatch body will also have an interconnection connector which will connect the car hatch wiring harness to the main body harness of the vehicle. We will be using a 2-pole electrical interconnection connector.

The bend ratio for all the bundle segments is considered to be 1.4

For the mounting solution, we will be using Hellermann Tyton Push-button cable tie mounts and Bundling Clips with Fir tree. The detailed dimensions for these mounts are shown below.

There will be instances when would require mounting holes and provisions in the car BIW body for routing the wiring harness with the help of clips and mounts. In this project, we will be requiring some holes and slots on the car sheet metal frame. The BIW design team for the car should be consulted and asked to provide these extra features in the sheet-metal BIW body during the stamping process. The final locations for all the holes and slots should be finalized by the BIW design team.

CONTENT-

STEP1- Creating context assembly

A context assembly has to be created which will serve as the main assembly for the car back door. The context assembly will contain the 3D-CAD data for the car body hatch and the car body harness geometrical bundle.

STEP2- Defining 2-pole connector electrically

The 2-pole connector used for this harness assembly is Deutsch "C-DT06-2S". The CAD data for this connector was downloaded from TE.com. To define the connector electrically we should define the geometrical parameters, bundle-connection point, and the connector-connection point for the downloaded connector.

STEP3- Adding connectors the to the 2 tail lights and the 2 license plate lights

All the 2-pole connectors are added inside the Body harness geometrical bundle assembly. Manipulation tools along with a compass, snap, and smart move features should be used to locate all the 4 connectors in their desired locations.

STEP4- Bundle Routing

We will start bundle routing from the interconnection connector. The bundle diameter for the main trunk is assumed to be 20mm. The bundle diameter leading to the four 2-pole connectors is assumed to be 5mm. Bend ratio is assumed to be 1.4 and slack value between 1-5% is used wherever needed.

STEP5- Protective Covering

Adding a protective covering to the harness bundle is important to keep the bundle together and protect it from any wear and tear. For the current harness assembly, we will be using a blue-color PVC tape. Start and end extremity should be given wherever needed for the tube.

STEP6- Checking Bundle Continuity

First, we have to make sure that the multi-branch able is selected and then we have to go in EDIT>SEARCH>ADVANCED>ELECTRICAL WORKBENCH>TYPE-BUNDLE SEGMENT>ATTRIBUTE-FULLY CONNECTED".

Selecting the "TRUE" option will show all the connected bundle segments while selecting the "FALSE" will show all the non-connected bundle segments.

For now, we will select "TRUE" and search for results. All the bundle segments are highlighted and found showing that all the bundle segments are electrically connected.

STEP8- Creating a flatten-drawing view for the wiring harness assembly

Make a new drawing file and define all the necessary drawing parameters. Insert the front-view of the harness assembly into the drawing file.

Define drawing properties as shown below. It should be noted that for the "dress-up" settings 3D wireframe is always "ON". If this setting is not selected then the bundle segments will not be visible on the drawing view.

Final drawing of the flatten-view of the car body wiring harness assembly with all the mounting clips and mounts.

CONCLUSION-

Routing of the wiring harness for the car body hatch assembly was done and the flatten-view drawing was prepared in CATIA-V5. Various packaging rules and constraints were considered while routing the harness. Industry best practices were implemented in the harness design. All necessary details like clamping selection, harness fixing requirements, harness continuity were provided in order to design the wiring harness.