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.

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 fo

llowed 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 12-pole electrical connector with a mounting clip feature as an 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.

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.

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.

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.

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. These connectors are shown in orange color for clarity.

Defining and locating interconnection connector:

A 12-pole "C-776438-4" connector and mounting cavity "C-1924487-2" is used as an interconnection connector. The 3-D CAD data file for the required connector and the cavity is downloaded from TE. com. Both the connector and the cavity are electrically defined and mounted near the already present slot on the car body hatch as shown below.

Defining Connector for Wiper moutning assembly:

A 3-pole "C-1-174357-2-7" connector is used as an Wiper assembly connector. The 3-D CAD data file for the required connector and the cavity is downloaded from TE. com.

The connector is electrically defined and mounted near the already present slot on the car body hatch as shown below.

Defining clip mounts as supports:

For the mounting solution, we will be using Hellermann Tyton Push-button cable tie mounts (Part no.- 155_30802) and Bundling Clips with Fir tree (Part no.- 151_14303). Both the clips were modeled using the dimensions given by the manufacturer. These clips have to be defined as support. To do so we have to define geometrical parameters and bundle entry and exit points from both left and right sides of the clips.

Locating and placing clips in the desired locations:

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 1.5 and slack value between 1-10% is used wherever needed.

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 PVC tape.

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.

Create flat-pattern of wiring harness bundle:

To make a flattened view of any wiring harness we should be working in the Electrical Harness Flattening workbench of CATIA V5. We should also make sure that the flattening file is saved in the same folder where we have all the parts of the harness assembly

While defining the Harness Flattening parameters make sure to use the "Single Line" for the Bundle segment and "Double Line" for the Protective covering.

Extract and bring the bundle assembly into the Car body flattening product file and then flatten the harness along the XY plane.

Flat the bundle assembly by usinf 'Flattern' feature in Flattenning workbench and should noted that the falttern in 'xy plane'. Also noted the algorithm and angle mode in regular. It changes bended branches to straight in nature.

Rotate the bundle segments connecting to the connectors by using the "Rotate" feature in the flattening workbench. It should be noted, that we have "XY-plane" as the flattening plane so we should make sure that we rotate the bundle segment only along the "XY-plane". For better representation, we can use some features like bend, roll to streamline the harness. At this stage, fake scaling can be done for a few bundle segments if needed.

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 Tail gate 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.