Key points of automobile harness layout

With the continuous improvement of modern automobile safety, comfort and environmental protection requirements, the number of circuits and power consumption on the automobile have increased significantly. How to arrange a large number of circuits more reasonably in the limited automobile space Wire harness It has become a problem facing the automobile manufacturing industry.

1、 Wire harness The fixed points are arranged reasonably and fixed reliably.

(1) According to the whole vehicle Wire harness In order to avoid sagging and displacement of the harness, considering the weight of the harness, the fixing method and the convenience of the fixing position, the harness must be fixed with enough reasonable fixing points and fixing methods.

(2) According to Wire harness The fixed points shall be set in the direction of the vehicle body and the specific shape of the vehicle body. On the straight-line distance without fulcrum, the distance between the two fixed points is generally no more than 300mm; A fixed point can be set at the obtuse angle inflection point; Two fixed points shall be set at the right angle inflection point; Avoid sharp corners and inflection points in the harness.

(3) Depend on Wire harness Select the type and size of the fixing buckle according to the shape and outer diameter of the harness to meet the needs of bearing the weight of the harness.

(4) With others Wire harness The position of the plug-in connected with the electrical equipment shall not exceed 120mm in front of the plug-in, and the fixed point shall be set.

(5) It is considered to set fixed points on the trunk line at the fulcrum position, and the distance between the fixed points and the fulcrum shall not exceed 100mm.

(6) There must be enough space in the installation direction of the fixed buckle to facilitate the installation and disassembly of the buckle.

2. The appearance is neat and configured into bundles.

（1） Wire harness The wiring harness shall be arranged along the edge and along the groove (wiring groove designed on the vehicle body) to avoid direct pressure on the harness. There shall be no exposed harness in the cab; The position of the harness can be observed, such as the position of the engine room, and eye-catching attraction points or eye-catching colors can be set. The harness installed here is not prominent or conspicuous.

(2) The arrangement mode is in the projection direction, which is arranged in a horizontal and vertical chessboard manner to avoid oblique line arrangement.

(3) The gap with the pipe shall be uniform and the gap with the surrounding components shall be reasonable.

3. Avoid Wire harness Interfere with surrounding components.

(1) Do not directly contact the sharp edges of the vehicle body. First, leave a gap, and second, increase protection to avoid damage to the sharp edges of the vehicle body Wire harness External insulation layer, resulting in short circuit accident;

(2) When installed on vibrating or moving parts, the length shall be reserved according to the actual situation. The reserved length is determined according to the vibration amplitude of the component and the maximum motion stroke of the moving component. Ensure that the reserved length will not transfer the vibration on the harness or make the harness bear the tension. If the harness is subjected to vibration transmission or tension for a long time, it may lead to virtual connection between internal contacts / plug-in terminals of the harness. For example, the connection between engine harness and engine compartment harness.

(3) The clearance with moving parts shall be greater than 25mm, such as the clearance between the wire of wiper motor and connecting rod.

(4) The distance from the exhaust manifold should be greater than 50 mm.

(5) The distance from parts with engine temperature greater than 150 ℃ is greater than 50mm.

(6) Do not use the same fixing points as the fuel and brake pipes.

(7) Do not cross or contact with fuel pipes and brake pipes. Especially in Wire harness The connecting parts and oil circuit connecting parts shall avoid damage to the line surface, short circuit and fire when the oil evaporation density reaches certain conditions.

4. Anti electromagnetic interference.

(1) Anti electromagnetic interference measures must be taken for the audio harness to ensure that the signal-to-noise ratio of audio system and other signals can work normally.

(2) The engine control module signal line, instrument signal line, ABS signal line and airbag signal line must be provided with anti electromagnetic interference measures (such as twisted pair, shielded wire, etc.), To ensure that all systems work properly.

(3) Avoid the electromagnetic interference source of parts. For example, arrange some signal wires as far away from the interference source as possible, such as horn, ignition coil, motor, etc.

(4) The sensor signal power line shall avoid the power line of high current components, and the interval shall be greater than 300mm to avoid interference with the signal.

(5) Arrange electrical appliances reasonably and shorten the length of signal line.

(6) The grounding wires of some key systems and important systems are arranged at one position respectively to avoid the interference of other grounding wires. For example, airbag system, ABS, ECU, engine control system and audio system all implement a two-wire system in the system, and the whole system adopts a grounding point.

(7) Add shielding grounding on the easily disturbed electrical enclosure.

5. Consider assembly process and maintenance process;

(1) During assembly, do not pull the harness too tightly (especially the transverse layout of the harness), so as to avoid the wrong position of the harness fixing point caused by the driving vehicle in the bumpy state, resulting in the instantaneous increase of the distance between the two fixing points, resulting in elongation Wire harness , resulting in pull-out / virtual connection of internal contacts of the harness, change of wire parameters, and even wire breakage.

(2)Wire harness After assembly, there shall be enough clearance around them to ensure that they will not be pressed by other parts or squeezed by other parts and their fasteners. Avoid grounding and other faults caused by pinch off, wear or rupture of harness insulation.

(3) Plug ins of the same model and color are not arranged nearby. Avoid misinsertion and damage during assembly Wire harness And electrical appliances.

(4) The plug-ins are arranged in a position easy to find and easy to operate by hands and tools. In order to facilitate inspection and maintenance, the conductor length of electrical equipment needs to be considered according to the actual assembly. If the electrical equipment is installed at a position where the surface is easy to operate, the wire can be omitted and the plug-in can be directly connected to the component; If the installation position of the electrical equipment is hidden and it is difficult to maintain and disassemble in the later stage, the length of the conductor brought by the electrical equipment can be appropriately increased as needed to make the plug-in arranged in a position convenient for inspection and maintenance.