A production process for wiring harnesses specifically designed for new energy vehicles

Abstract

The present invention discloses a production process for a wiring harness specifically for new energy vehicles, comprising the following steps: S1, preparing materials; S2, cutting the wires; S3, pre-inserting the main conductor into the hole of the sheath sealing rear cover, installing a sealing plug, dividing each main conductor into two ends A and B, with one end close to the sealing plug being the main conductor A end and the other end being the main conductor B end, performing a crimping process on the shielding rings at the two main conductor A ends, assembling a high-voltage sheath, performing a crimping process on the shielding rings at the two main conductor B ends, fixing two single auxiliary conductors to the two main conductors, twisting the wires, pre-installing a black double-wall heat shrink tubing, ultrasonic welding, and heating the black double-wall heat shrink tubing; S4, wrapping with glue and assembling; S5, performing a pull-out test, a continuity test, a size inspection, an appearance inspection, and finished product packaging, and storing qualified finished products to complete the production process for the wiring harness specifically for new energy vehicles. The production process proposed by the present invention has a high pass rate, and the produced wiring harness has excellent performance and a long service life.

Description

Technical Field

[0001] The present invention relates to the technical field of wire harness production technology, and in particular to a production process of a wire harness dedicated to new energy vehicles. Background Art

[0002] New energy vehicles (NEVs) are vehicles that utilize unconventional fuels as their power source and integrate advanced technologies in vehicle power control and drive, resulting in advanced technical principles, new technologies, and new structures. Due to their fuel efficiency, low exhaust emissions, environmental friendliness, and high efficiency, NEVs have seen a year-on-year increase in usage and are becoming a future automotive development trend. Wiring harnesses, the carrier of NEV circuits, play a crucial role in the entire NEV operation process. New energy vehicles, especially electric vehicles, are powered by battery systems, and wiring harnesses are the carrier of DC transmission. This requires wiring harnesses with high voltage, high current, and high temperature resistance. Due to the recent rise of NEVs, the current supply of supporting materials remains limited. For example, conventional wiring harness production processes cannot meet the high demands of NEV wiring harnesses. Existing NEV wiring harness manufacturers are few and far between, their technology is immature, resulting in low yield rates for finished wire harnesses and short service lives. Therefore, the search for a simple, efficient, and high-performance NEV wiring harness production process is a pressing challenge for wiring harness manufacturers. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems in the prior art of immature wire harness production technology, low production qualification rate and short life of the produced wire harness, and to propose a production process for a special wire harness for new energy vehicles.

[0004] A production process for a wiring harness specifically for new energy vehicles comprises the following steps:

[0005] S1. Preparation: Prepare the materials required for wire harness production;

[0006] S2. Wire cutting: Check whether the main conductor size meets the design requirements. If it meets the requirements, position the main conductor to be cut according to the design requirements. The ratio of the insulation stripping length at the cutting position to the required stripping length is 2 to 2.5:3. Cut perpendicular to the axial direction of the main conductor and conduct an appearance inspection. The acceptance standard is that there are no broken core wires, uneven core wires, damaged core wires, bent core wires, wire insulation residue, and unpeeled rubber.

[0007] S3. Pre-installation, crimping, twisting, and ultrasonic welding: Pre-insert the two main conductors cut in step S2 into different holes in the same sheath sealed rear cover, and then install sealing plugs separately. Divide each main conductor into two ends A and B, with the end close to the sealing plug as the main conductor A end, and the end close to the sheath sealed rear cover as the main conductor B end. Crimping the shielding rings at the A ends of the two main conductors, assembling the high-voltage sheath, crimping the shielding rings at the B ends of the two main conductors, stripping the two single auxiliary conductors and fixing them to the two main conductors respectively, then twisting the two single auxiliary conductors, and pre-installing black double-wall heat shrink tubing, ultrasonically welding, and heating the black double-wall heat shrink tubing;

[0008] S4, Glue wrapping assembly: Wrap the main conductor with 1 to 2 turns of PVC tape, and wrap the corrugated tube 20mm away from the root of the sheath with 30 to 50mm of orange cloth-based tape;

[0009] S5. Post-processing: Conduct pull-out test, continuity test, dimension inspection, appearance inspection, finished product packaging, and put qualified finished products into storage to complete the production process of special wire harnesses for new energy vehicles.

[0010] Preferably, in step S3, the shielding ring crimping process at the end A of the main conductor includes the following steps:

[0011] A. Comb the shield layer: Flanged the shield layer at the A end of the main conductor, leaving no remaining flying threads;

[0012] B. Tangent: Perform the tangent operation on the inner core of the main conductor end A in step S2;

[0013] C. Install shielding ring: Install the sheath shielding inner ring, ensure that the sheath shielding inner ring is flush with the outer skin stripping port, install the sheath shielding outer ring that matches the sheath shielding inner ring outside the shielding layer, and the shielding layer is evenly distributed on the sheath shielding inner ring, and the middle position of the sheath shielding outer ring is against the incision, trim the shielding layer, and do not scratch the wire skin. There should be no residual flying wires on the shielding layer. The thickness of the shielding layer after trimming should not exceed 1mm;

[0014] D. Crimping the terminal: Place the terminal just below the pressing piece in the mold, ensuring that both sides of the terminal gripping part are even. Place the main conductor A end processed in step C into the terminal and crimp it.

[0015] E. Crimping the shielding ring: Use a hexagonal crimping machine to crimp the back ring of the shielding ring. When crimping, the inner and outer shielding rings should be flush. The crimping should be firm and reliable. No shielding layer should be exposed, and the insulation and wire core should not be damaged. This completes the crimping of the shielding ring at the A end of the main conductor.

[0016] Preferably, in step D, when the main conductor A is placed in the terminal, the exposed main conductor core wires on both sides of the conductor gripping portion of the terminal are within the terminal installation specification range, and the ratio of the exposed main conductor core wire length between the conductor gripping portion and the insulator gripping portion to the exposed main conductor skin length is 1:1.

[0017] Preferably, in step E, after the shielding ring is crimped, the outer shielding ring is 18.1 mm to 20.1 mm away from the front root of the terminal.

[0018] Preferably, in step S3, assembling the high-voltage sheath includes the following steps:

[0019] a. Repackaging: Insert the two main conductors’ A-end terminals into the high-voltage sheath in the same direction with the crimping area facing upwards, push the sealing plugs tightly, lock them, and install the positioning card;

[0020] b. Cut and install the corrugated tube and the wire rack components: Cut the corrugated tube according to the design requirements, insert the main wire end B into the corrugated tube, and then install the main wire fixing terminals on the B ends of the two main wires respectively. Clamp them with a fixture, and then install the two main wires in the two-hole sealing plugs inside the same wire rack, and then install the wire rack;

[0021] c. Fix the bellows and wire rack components: Move the wire rack toward the main wire fixing terminal, bend the main wire and the bellows until the end of the bellows close to the main wire fixing terminal is stuck in the slot of the wire rack, then install the wire rack cover, lock the locking point of the wire rack cover, and complete the assembly of the high-voltage sheath.

[0022] Preferably, in step c, when the main conductor and the corrugated tube are bent, the wing end of the wire frame faces upward, and the bellows are bent until the 3-4 teeth of the bellows close to the main conductor fixed terminal end are clamped on the clamping groove of the wire frame.

[0023] Preferably, in step S3, the shielding ring crimping process at the end B of the main conductor includes the following steps:

[0024] Ⅰ. Trim the shielding layer: peel off the outer skin of the main conductor and trim the shielding layer to a length of 5 to 6 mm;

[0025] Ⅱ. Install the shielding ring: First pre-thread the shielding outer ring to the outside of the main conductor, install the shielding inner ring to the shielding layer, and turn the shielding layer over to cover the shielding inner ring;

[0026] III. Crimping the shielding ring: Crimping the outer shielding ring and inserting the heat shrink tubing with adhesive at the clamping point. After crimping, trim the excess shielding layer and heat-bake the heat shrink tubing with adhesive in the middle.

[0027] IV. Wire cutting and terminal crimping: Cut the B end of the main conductor according to the operation steps of step S2, pre-install the black heat shrink tubing without glue, crimp the terminal, and heat-bake the black heat shrink tubing without glue to complete the crimping of the shielding ring at the B end of the main conductor.

[0028] Preferably, in step S3, the method for fixing the single guide wire to the main wire is to strip the single guide wire and stick the single guide wire on the shielding layer before crimping the shielding outer ring in step III, and then fix it to the main wire while crimping the shielding outer ring.

[0029] The production process proposed by the present invention has a complete flow and detailed content. It constitutes a complete production process of wiring harnesses for new energy vehicles through material preparation - wire cutting - pre-installation, crimping, twisting, ultrasonic welding - glue wrapping assembly - post-processing. In view of the problems existing in the prior art, the present invention utilizes strict control of special production parameters during the production process to reduce the problems encountered in traditional production, thereby improving the product qualification rate, reducing the output of unqualified products, improving the utilization rate of raw materials, and ensuring production efficiency. In particular, during the wire cutting process, the ratio of the insulation stripping length at the wire cutting position to the designed stripping length is controlled to ensure the electrical characteristics of the wire. When performing the crimping operation, the positional relationship between the main wire A and the terminal conductor gripping part and the insulator gripping part is controlled to ensure the accuracy of the crimping and avoid crimping. Defects have adverse effects on product performance such as increased resistance, weakened tensile strength, etc., and at the same time, they also avoid terminal deformation and cracking, broken wires at the edges of the conductor gripping parts, defects or damage in the fitting parts, poor crimping and other problems, which have a negative impact on subsequent production and product qualification rate, product performance, production efficiency and production cost; in addition, the present invention combines the crimping treatment of the shielding ring at the end of the main conductor A, the assembly of the high-voltage sheath and the crimping treatment of the shielding ring at the end of the main conductor B during the crimping process, and strictly controls the above three processes, which significantly improves the qualification rate of the product and ensures that the produced wire harness has excellent characteristics, effectively avoiding the problems of immature existing wire harness production technology, low production qualification rate and short life of the produced wire harness, and has considerable development prospects and good social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a production process flow chart of a special wiring harness for new energy vehicles proposed by the present invention;

[0031] Figure 2 This is a diagram of the BK5.5-5 terminal analysis and measurement system in an embodiment of the present invention;

[0032] Figure 3 This is a product diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further explained below with reference to specific embodiments.

[0034] Example

[0035] The present invention proposes a production process for a wiring harness specifically for new energy vehicles, comprising the following steps:

[0036] S1. Preparation: Prepare the materials required for wire harness production;

[0037] S2. Wire cutting: Check whether the main conductor size meets the design requirements. If it meets the requirements, position the main conductor to be cut according to the design requirements. The ratio of the insulation stripping length at the tangent position to the required stripping length is 2:3. Cut perpendicular to the axial direction of the main conductor and conduct an appearance inspection. The acceptance standard is that there are no broken core wires, uneven core wires, damaged core wires, bent core wires, wire insulation residue, and unpeeled rubber.

[0038] S3. Pre-installation, crimping, stranding, and ultrasonic welding: Pre-thread the two main conductors cut in step S2 into different holes in the same sheath sealing back cover, then install sealing plugs into each of them. Divide each main conductor into two ends, A and B. The end closest to the sealing plug is the main conductor end A, and the end closest to the sheath sealing back cover is the main conductor end B.

[0039] Crimping the shield rings at the A ends of the two main conductors includes the following steps:

[0040] A. Comb the shield layer: Flanged the shield layer at the A end of the main conductor, leaving no remaining flying threads;

[0041] B. Tangent: Perform the tangent operation on the inner core of the main conductor end A in step S2;

[0042] C. Install shielding ring: Install the sheath shielding inner ring, ensure that the sheath shielding inner ring is flush with the outer skin stripping port, install the sheath shielding outer ring that matches the sheath shielding inner ring outside the shielding layer, and the shielding layer is evenly distributed on the sheath shielding inner ring, and the middle position of the sheath shielding outer ring is against the incision, trim the shielding layer, and do not scratch the wire skin. There should be no residual flying wires on the shielding layer. The thickness of the shielding layer after trimming should not exceed 1mm;

[0043] D. Crimping the terminal: Place the terminal directly below the pressing piece in the mold, ensuring that both sides of the terminal grip are even. Place the main conductor end A treated in step C into the terminal. Ensure that the exposed main conductor cores on both sides of the conductor grip are within the terminal installation specifications, and the ratio of the exposed main conductor core length between the conductor grip and the insulator grip to the exposed main conductor sheath length is 1:1. Crimping is then performed.

[0044] E. Crimping the shielding ring: Use a hexagonal crimping machine to crimp the rear ring of the shielding ring. When crimping, the inner and outer shielding rings should be flush with each other. The crimping should be firm and reliable. No shielding layer should be exposed, and the insulation and wire core should not be damaged. The outer shielding ring should be 19.1mm away from the front root of the terminal. This completes the crimping of the shielding ring at the A end of the main conductor.

[0045] Assembling the high voltage sheath includes the following steps:

[0046] a. Repackaging: Insert the two main conductors’ A-end terminals into the high-voltage sheath in the same direction with the crimping area facing upwards, push the sealing plugs tightly, lock them, and install the positioning card;

[0047] b. Cut and install the corrugated tube and the wire rack components: Cut the corrugated tube according to the design requirements, insert the main wire end B into the corrugated tube, and then install the main wire fixing terminals on the B ends of the two main wires respectively. Clamp them with a fixture, and then install the two main wires in the two-hole sealing plugs inside the same wire rack, and then install the wire rack;

[0048] c. Fix the bellows and wire rack components: Move the wire rack toward the main wire fixing terminal with the wing end of the wire rack facing upwards, bend the main wire and the bellows until the bellows is close to the main wire fixing terminal and 3 to 4 teeth of the bellows are clamped on the clamping groove of the wire rack, then install the wire rack cover and lock the locking point of the wire rack cover to complete the assembly of the high-voltage sheath.

[0049] Crimping the shield rings at the B ends of the two main conductors includes the following steps:

[0050] Ⅰ. Trim the shielding layer: peel off the outer skin of the main conductor and trim the shielding layer to a length of 5 to 6 mm;

[0051] Ⅱ. Install the shielding ring: First pre-thread the shielding outer ring to the outside of the main conductor, install the shielding inner ring to the shielding layer, and turn the shielding layer over to cover the shielding inner ring;

[0052] III. Crimping the shielding ring: Crimping the outer shielding ring and inserting a Φ6.4*35 heat shrink tube with adhesive at the clamping point. After crimping, trim the excess shielding layer and heat-dry the Φ6.4*35 heat shrink tube with adhesive in the center.

[0053] IV. Wire cutting and terminal crimping: Follow the steps in step S2 to cut the wire end B of the main conductor, pre-install a Φ5*35 black heat shrink tubing without glue, crimp the terminal BK5.5-5, and heat-bake the Φ5*35 black heat shrink tubing without glue to complete the crimping of the shield ring at the end B of the main conductor.

[0054] Strip the ends of the single guide wire and attach it to the shield layer before crimping the outer shield ring in step III. Secure it to the main wire while crimping the outer shield ring. Twist the two guide wires together and pre-install Φ3.2*35 black double-wall heat shrink tubing. Ultrasonic weld and heat the Φ3.2*35 black double-wall heat shrink tubing.

[0055] S4, Glue wrapping assembly: Wrap the main conductor with 2 turns of PVC tape, and wrap the corrugated tube 20mm away from the root of the sheath with 40mm orange cloth-based tape;

[0056] S5. Post-processing: Conduct pull-out test, continuity test, dimension inspection, appearance inspection, finished product packaging, and put qualified finished products into storage to complete the production process of special wire harnesses for new energy vehicles.

[0057] The same component for the same new energy vehicle was produced using the process of the embodiment and the existing production harness. The qualification rate and product performance of the two production processes were evaluated. The produced harness was tested for service life, high voltage resistance, and high temperature resistance. The embodiment was evaluated based on the process results of the existing production harness. The results are as follows:

[0058] Example Existing production process Pass rate +18.8％ —— Service life +8.3％ —— Hi-pot test +3.2％ —— High temperature resistance test +5.9％ ——

[0059] In the table, “+” indicates that the corresponding item of the embodiment is improved compared with the existing production process.

[0060] Experimental results show that the embodiments proposed in the present invention have significantly improved qualification rates, product life, pressure resistance, and high temperature resistance compared to existing production processes.

[0061] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A production process for a wiring harness specifically for new energy vehicles, characterized in that: The following steps are involved: S1. Preparation: Prepare the materials required for wire harness production; S2. Wire cutting: Check whether the main conductor size meets the design requirements. If it meets the requirements, position the main conductor to be cut according to the design requirements. The ratio of the insulation stripping length at the cutting position to the required stripping length should be 2 to 2.5:

3. Cut the wire perpendicular to the axial direction of the main conductor and conduct an appearance inspection. The acceptance standard is that there are no broken core wires, uneven core wires, damaged core wires, bent core wires, wire insulation residue, and unstripped rubber. S3. Pre-installation, crimping, twisting, and ultrasonic welding: Pre-insert the two main conductors cut in step S2 into different holes in the same sheath sealed rear cover, and then install sealing plugs separately. Divide each main conductor into two ends A and B, with the end close to the sealing plug as the main conductor A end, and the end close to the sheath sealed rear cover as the main conductor B end. Crimping the shielding rings at the A ends of the two main conductors, assembling the high-voltage sheath, crimping the shielding rings at the B ends of the two main conductors, stripping the two single auxiliary conductors and fixing them to the two main conductors respectively, then twisting the two single auxiliary conductors, and pre-installing black double-wall heat shrink tubing, ultrasonically welding, and heating the black double-wall heat shrink tubing; S4, Glue wrapping assembly: Wrap the main conductor with 1 to 2 turns of PVC tape, and wrap the corrugated tube 20mm away from the root of the sheath with 30 to 50mm of orange cloth-based tape; S5. Post-processing: Conduct pull-out test, continuity test, dimension inspection, appearance inspection, finished product packaging, and store qualified finished products to complete the production process of new energy vehicle dedicated wiring harness; In step S3, the shielding ring crimping process at the end A of the main conductor includes the following steps: A. Comb the shield layer: Flanged the shield layer at the A end of the main conductor, leaving no remaining flying threads; B. Tangent: Perform the tangent operation on the inner core of the main conductor end A in step S2; C. Install shielding ring: Install the sheath shielding inner ring, ensure that the sheath shielding inner ring is flush with the outer skin stripping port, install the sheath shielding outer ring that matches the sheath shielding inner ring outside the shielding layer, and the shielding layer is evenly distributed on the sheath shielding inner ring, and the middle position of the sheath shielding outer ring is against the incision, trim the shielding layer, and do not scratch the wire skin. There should be no residual flying wires on the shielding layer. The thickness of the shielding layer after trimming should not exceed 1mm; D. Crimping the terminal: Place the terminal directly below the pressing piece in the mold, ensuring that both sides of the terminal grip are even. Place the main conductor A end treated in step C into the terminal and crimp. When the main conductor A is placed in the terminal, the exposed main conductor cores on both sides of the conductor grip are within the terminal installation specifications, and the ratio of the exposed main conductor core length between the conductor grip and the insulator grip to the exposed main conductor sheath length is 1:

1. E. Crimping the shielding ring: Use a hexagonal crimping machine to crimp the back ring of the shielding ring. When crimping, the inner and outer shielding rings should be flush. The crimping should be firm and reliable. No shielding layer should be exposed, and the insulation and wire core should not be damaged. This completes the crimping of the shielding ring at the A end of the main conductor.

2. The production process of a special wiring harness for new energy vehicles according to claim 1, characterized in that: In step E, after the shielding ring is crimped, the outer shielding ring is 18.1 mm to 20.1 mm away from the front root of the terminal.

3. The production process of a special wiring harness for new energy vehicles according to claim 1, characterized in that: In step S3, assembling the high-voltage sheath includes the following steps: a. Repackaging: Insert the two main conductors’ A-end terminals into the high-voltage sheath in the same direction with the crimping area facing upwards, push the sealing plugs tightly, lock them, and install the positioning card; b. Cut and install the corrugated tube and the wire rack components: Cut the corrugated tube according to the design requirements, insert the main wire end B into the corrugated tube, and then install the main wire fixing terminals on the B ends of the two main wires respectively. Clamp them with a fixture, and then install the two main wires in the two-hole sealing plugs inside the same wire rack, and then install the wire rack; c. Fix the bellows and wire rack components: Move the wire rack toward the main wire fixing terminal, bend the main wire and the bellows until the end of the bellows close to the main wire fixing terminal is stuck in the slot of the wire rack, then install the wire rack cover, lock the locking point of the wire rack cover, and complete the assembly of the high-voltage sheath.

4. The production process of a wiring harness for new energy vehicles according to claim 3, characterized in that: In step c, when the main conductor and the corrugated tube are bent, the wing end of the wire guide frame faces upward, and the corrugated tube is bent until the 3-4 teeth of the corrugated tube are close to the main conductor fixed terminal end and are clamped on the clamping groove of the wire guide frame.

5. The production process of a special wiring harness for new energy vehicles according to claim 1, characterized in that: In step S3, the shielding ring crimping process at the end B of the main conductor includes the following steps: Ⅰ. Trim the shielding layer: peel off the outer skin of the main conductor and trim the shielding layer to a length of 5 to 6 mm; Ⅱ. Install the shielding ring: First pre-thread the shielding outer ring to the outside of the main conductor, install the shielding inner ring to the shielding layer, and turn the shielding layer over to cover the shielding inner ring; III. Crimping the shielding ring: Crimping the outer shielding ring and inserting the heat shrink tubing with adhesive at the clamping point. After crimping, trim the excess shielding layer and heat-bake the heat shrink tubing with adhesive in the middle. IV. Wire cutting and terminal crimping: Cut the B end of the main conductor according to the operation steps of step S2, pre-install the black heat shrink tubing without glue, crimp the terminal, and heat-bake the black heat shrink tubing without glue to complete the crimping of the shielding ring at the B end of the main conductor.

6. The production process of a special wiring harness for new energy vehicles according to claim 5, characterized in that: In step S3, the method for fixing the single guide wire to the main wire is to strip the single guide wire and stick the single guide wire on the shielding layer before crimping the shielding outer ring in step III, and then fix it to the main wire during the operation of crimping the shielding outer ring.

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