Project 2

AIM:

• To route the wiring harness for the given Tailgate.
• Application of all Packaging rules, Industry best practices studied in this course shall be demonstrated in design.
• Apply Protection coverings as required.

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 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.

INTRODUCTION:

WIRING HARNESS OR CABLE HARNESS:

A cable harness, also known as a wire harness, wiring harness, cable assembly, wiring assembly, or wiring loom, is an assembly of electrical cables or wires which transmit signals or electrical power. The cables are bound together by a durable Material such as rubber, vinyl, electrical tape, conduit, a weave of extruded string, or a combination there of.

1. Wiring Harness

Cable harnesses are usually designed according to geometric and electrical requirements. A diagram is then provided (either on paper or on a monitor) for the assembly preparation and assembly.

The wires are first cut to the desired length, usually using a special wire-cutting machine. The wires may also be printed on by a special machine during the cutting process or on a separate machine. After this, the ends of the wires are stripped to expose the metal (or core) of the wires, which are fitted with any required terminals or connector housings. The cables are assembled and clamped together on a special workbench, or onto a pinboard (assembly board), according to design specification, to form the cable harness. After fitting any protective sleeves, conduit, or extruded yarn, the harness is either fitted directly in the vehicle or shipped.

DESIGN METHODOLOGY

The design methodology or design approach which is used for this challenge is explained or given in the below flow chart,

DESIGN CRITERIA AND PACKAGING ASSUMPTIONS:

• Wiring harness routing shall provide ease in manufacturing, accessibility, easy removal, and easy maintenance of attached equipment and wiring harness.
• Routing through small structural holes and openings shall be avoided, minimize chaffing and handling of the wiring harness during installation.
• Avoid the harness routing and clipping in the Blind zone of the Operator during harness assembly or in service.
• Routing shall offer protection against possible damage through common misuses such as being handhold and temporary support for test equipment.
• Provide additional slack to the harness according to the surroundings and harness bending requirements.
• Ensure the routing meets the clearance requirements with different surrounding parts.
• Avoid routing over the bolts, near to the bolted joints. It may damage the harness or puncture the harness. Keep harness away from panel mounting screws.
• Avoid harness routing near sharp edges, if not possible provide protection to the harness.
• The maximum distance between two clips on a straight branch is 200mm.
• Provide Clips and clamps if the harness is going to bend at multiple locations.
• The use of too many sheet-metal brackets should be avoided.
• The branch length should be more than 50 mm.
• Min distance between clip and branching point to be 25 mm.
• Min distance between two branch breakouts should be 50 mm.

Given:

Car Tailgate Assembly

COMPONENTS:

Defining all as the electrical and support components.

Routing of the wiring harness

Application of protection coverings

Preparing the flattening view of the wiring harness assembly

Drafting of the Wiring Harness :

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.