Preparation process of automobile steering wheel power-assisted system wire harness and product

Abstract

The application relates to the field of automobile wire harnesses, and discloses a preparation process and product of an automobile steering wheel power-assisted system wire harness. The preparation process of the automobile steering wheel power-assisted system wire harness comprises the following steps: cutting a core wire, partially peeling an A end, fully peeling a B end, and pressing a terminal at the B end; assembling an A end wire sleeve: sequentially inserting the A end of the core wire into connecting holes of the A end wire sleeve, and the core wire extends a distance along the A end wire sleeve; cutting a sleeve pipe, and sleeving a sleeve pipe outside the core wire along the B end of the core wire; assembling a B end connector: sequentially inserting the B end of the core wire into connecting grooves of the B end connector, and detecting; wherein, before assembling the B end connector, injecting insulating glue into the connecting grooves of the B end connector, and solidifying after the B end of the core wire is inserted. Advantageous effects: the sensitivity stability is good under long-term frequent temperature difference changes, and the connector of the wire harness cannot be loosened or fallen off in the vibration process of vehicle driving.

Description

Technical Field

[0001] This application relates to the field of automotive wiring harness processing, and in particular to a manufacturing process and product for an automotive power steering system wiring harness. Background Technology

[0002] The wiring harness of a car's power steering system primarily transmits commands and data. It is responsible for transmitting the status of various sensors and the driver's operating intentions to the car's electronic control unit (ECU) in the form of electrical signals quickly and accurately. Based on the ECU's instructions, the power steering motor is driven to generate auxiliary torque, easily helping the driver turn the steering wheel.

[0003] In existing automotive power steering systems, the wiring harness connects to the PCB board of the power steering motor at one end and to the vehicle's infotainment system at the other. It is typically manufactured using processes such as wire cutting, stripping, crimping terminals, and assembling connectors. Connectors link the ends of the wiring harness, facilitating connection to the relevant components.

[0004] However, during long-term use, the wiring harness of the power steering system needs to withstand frequent temperature changes inside the vehicle, which can easily reduce the sensitivity of the wiring harness and affect its service life. In addition, the continuous vibration generated when the vehicle is in motion can cause the connectors of the wiring harness to loosen or fall off, resulting in open circuits and reducing the driving safety of the vehicle. Summary of the Invention

[0005] To address the issues that existing automotive power steering system wiring harnesses are prone to reduced sensitivity under long-term and frequent temperature changes, and that connectors in the wiring harnesses are prone to loosening or falling off during vehicle vibrations, this application provides a manufacturing process and product for automotive power steering system wiring harnesses.

[0006] In a first aspect, this application provides a manufacturing process for a wiring harness for an automotive power steering system, employing the following technical solution: A manufacturing process for a wiring harness for an automotive power steering system includes the following steps: Cut several core wires to the required length, then partially strip the insulation from end A of several core wires, fully strip the insulation from end B, and crimp a terminal to end B. Assemble the A-end sleeve: According to the assembly requirements, insert the A ends of several core wires into the connection holes of the A-end sleeve in sequence, and each core wire extends a certain distance along the A-end sleeve. Cut the sleeve and place one sleeve around the outside of several core wires along the B end of several core wires. Assembly of B-end connector: According to the assembly requirements, insert the B ends of several core wires into the connection slots of the B-end connector in sequence, test, and obtain the automotive power steering system wiring harness. Before assembling the B-end connector, inject insulating glue into the connection slot of the B-end connector, and then allow several core wires to be inserted into the B-end for curing.

[0007] By adopting the above technical solution, the wire cutting makes the core wire meet the actual use requirements. The A end is partially stripped to facilitate the assembly of the A end wire sleeve, and the end is easy to connect to the PCB board of the power steering motor of the car steering wheel. The B end is fully stripped and crimped with terminals to facilitate the assembly of the B end connector, and thus facilitate the connection with the car's infotainment system.

[0008] The sleeve is fitted over the outside of the core wires to form an overall protective covering for multiple core wires, reducing frictional loss between the core wires, while enhancing the overall structural stability of the wire harness and further resisting the adverse effects of vibration and temperature differences.

[0009] After the insulating adhesive cures, it forms a tight adhesive seal between the B end of the core wire and the connector groove. On the one hand, it fills the gap between the core wire and the connector, blocking the direct impact of external temperature differences on the core wire connection, and avoiding poor contact between the core wire and the connector due to thermal expansion and contraction, thereby maintaining the sensitivity of the wiring harness signal transmission and extending its service life. On the other hand, the cured insulating adhesive forms a rigid-flexible fixing layer that firmly locks the B end of the core wire in the groove, resisting continuous vibration during vehicle operation, preventing the connector from loosening or falling off, avoiding the risk of open circuit, and improving vehicle driving safety.

[0010] Preferably, the insulating adhesive is made from the following raw materials in parts by weight: 70-80 parts of hydroxyl-terminated polymethylvinylsiloxane-polydimethylsiloxane copolymer 8-12 parts of isocyanate mixture 20-30 parts of insulating filler 3-5 parts crosslinking agent Catalyst 0.5-1 part.

[0011] By adopting the above technical solution, hydroxyl-terminated polymethylvinylsiloxane-polydimethylsiloxane copolymer is used as the matrix, combining the high elasticity of polymethylvinylsiloxane and the high and low temperature resistance of polydimethylsiloxane, providing a good foundation for the flexibility and temperature difference resistance of the insulating adhesive. The isocyanate mixture undergoes an addition reaction with the hydroxyl groups of the matrix to form a cross-linked network, which improves the adhesive strength and cohesion of the insulating adhesive, ensuring a stable connection between the core wire and the connector; the addition of insulating filler significantly improves the insulation performance. The cross-linking agent and catalyst work synergistically to promote the heating cross-linking reaction and assist the room temperature moisture curing reaction, thereby controlling the curing rate of the insulating adhesive. This ensures rapid setting during the production process and forms a dense cross-linked structure, enhancing aging resistance and vibration resistance; at the same time, optimizing the dosage of each component achieves a balance between adhesive strength, flexibility, and insulation, improving the sensitivity, stability, and fixation stability of the resulting wire harness, making it less prone to loosening and falling off.

[0012] Preferably, the isocyanate mixture consists of octadecyl isocyanate and N-(p-maleimide phenyl) isocyanate in a weight ratio of (3-5):1.

[0013] By adopting the above technical solution, the long-chain alkyl structure of octadecyl isocyanate endows the insulating adhesive with excellent flexibility and hydrophobic properties, enhancing the adhesive layer's ability to buffer vibrations while resisting moisture corrosion inside the vehicle. N-(p-maleimide-phenyl)isocyanate contains maleimide groups, which possess excellent heat resistance and rigidity, enhancing the adhesive layer's resistance to high-temperature aging and adapting to the temperature variation environment inside the vehicle. These two components work synergistically to ensure the stability of the adhesive layer during long-term temperature cycling, further extending the lifespan of the wiring harness.

[0014] Preferably, the crosslinking agent is composed of a vinyl, propyl and ethoxy oligomeric siloxane and a methyltrimethoxysilane in a weight ratio of 1:(2-4).

[0015] By adopting the above technical solution, the vinyl groups in the low-molecular-weight siloxane containing vinyl, propyl, and ethoxy groups can undergo free radical cross-linking with the vinyl groups on the matrix side chains. The propyl and ethoxy groups enhance compatibility with the matrix and strengthen the density of the cross-linked network. Methyltrimethoxysilane, as a multifunctional silane, can hydrolyze by absorbing moisture from the air at room temperature. The resulting silanol groups can undergo condensation reactions with the matrix hydroxyl groups and other silane hydroxyl groups to form a Si-O-Si inorganic cross-linked structure, improving the adhesive layer's resistance to high and low temperatures and its insulation stability. These two components work synergistically to ensure the cohesive strength and aging resistance of the cured adhesive layer, maintain its flexible buffering performance, and meet the requirements of wire harness use in vibration environments.

[0016] Preferably, the total stripping length of the A end of the core wire is 13±1mm, and the half-stripping length is 4±1mm; the stripping length of the B end of the core wire is 3.25±0.25mm.

[0017] By adopting the above technical solutions, the precise stripping length design adapts to the connection requirements of the A end to the PCB board and the B end to the connector: the half-stripped structure of the A end ensures the effective soldering area between the core conductor and the PCB board, while providing protection through the unstripped insulation layer, avoiding short circuits caused by excessive conductor exposure during soldering; the 4±1mm half-stripping length balances soldering convenience and connection stability. The 3.25±0.25mm stripping length of the B end is precisely matched with the crimping process, ensuring a tight crimp between the terminal and the conductor, avoiding short circuits caused by excessively long stripping or weak crimping and poor signal transmission caused by excessively short stripping; at the same time, the standardized stripping length improves production consistency and ensures the quality stability of mass production of wire harnesses.

[0018] Preferably, before assembling the A-end sleeve, a rubber protective coil needs to be inserted into the connection hole of the A-end sleeve, then the rubber protective coil is opened, and the A end of the core wire is inserted into the rubber protective coil.

[0019] By adopting the above technical solution, the rubber protective coil has good elasticity and sealing performance. After being stretched, it fits tightly with the insulation layer of the core wire, forming the first sealing barrier, preventing dust, moisture and other impurities from entering the gap between the core wire and the sleeve, avoiding signal transmission interference or accelerated aging of the core wire due to the accumulation of impurities. The elastic structure of the rubber protective coil can buffer the impact of vehicle vibration on the A end of the core wire, reduce frictional loss at the connection between the core wire and the sleeve, and prevent the core wire from shifting due to vibration, ensuring the stability of the connection between the core wire and the PCB board, and further improving the vibration resistance and service life of the wire harness.

[0020] Preferably, the B-end connector is provided with a locking structure. After the B-ends of several core wires are inserted into the connecting groove, they are locked first and then cured.

[0021] By adopting the above technical solution, the locking structure mechanically fixes the B end of the core wire before curing, preventing the core wire from shifting due to vibration or movement during the curing process of the insulating adhesive. This ensures precise alignment between the core wire and the connector contacts, guaranteeing the accuracy of signal transmission. The mechanical locking and subsequent insulating adhesive curing form a dual fixing structure. The locking structure provides immediate stability, while the cured insulating adhesive provides long-term adhesion. The synergistic effect of both greatly enhances the connection strength between the core wire and the connector, effectively resisting severe vibrations during vehicle operation, completely solving the problem of connector loosening and detachment, and further ensuring driving safety.

[0022] Secondly, this application provides a wiring harness for an automotive steering wheel power assist system, employing the following technical solution: A power steering system wiring harness for automobiles is manufactured using the aforementioned manufacturing process.

[0023] By adopting the above technical solution, the wire harness has excellent signal transmission sensitivity, temperature difference resistance, vibration resistance and connection stability, and its service life is significantly extended. The wiring harness has good insulation, sealing performance and structural stability, which can effectively avoid faults such as open circuit and short circuit, ensure the stable operation of the power steering system of the car, and improve driving safety and comfort. At the same time, the standardized manufacturing process ensures the consistency and reliability of the wiring harness in mass production, and meets the mass production needs of the automotive manufacturing industry.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. Significantly improved connection stability: Through multiple fixing designs including insulating adhesive curing, locking structure, and rubber coil protection, combined with the high adhesive strength formula of the insulating adhesive, the problem of connector loosening and falling off caused by vehicle vibration is completely solved, avoiding open circuit faults and ensuring driving safety. 2. Temperature resistance and extended service life: The insulating adhesive matrix is ​​made of high and low temperature resistant silicone copolymer, combined with composite isocyanate and crosslinking agent to form a dense crosslinked network, which resists frequent temperature changes in the vehicle, avoids poor contact caused by thermal expansion and contraction at the core wire connection parts, maintains the sensitivity of the wire harness signal transmission, and extends the service life.

[0025] 3. Excellent insulation and signal transmission performance: The addition of insulating filler and precise stripping and assembly processes ensure that the wiring harness has good insulation performance, avoiding the risk of short circuits and leakage; the standardized connection structure design ensures the speed and accuracy of signal transmission, adapting to the command and data transmission requirements of the steering wheel power assist system. Attached Figure Description

[0026] Figure 1 This is a structural schematic diagram of the automotive power steering system wiring harness of this application; Figure 2 This is a front view of the A-end sleeve of the automotive power steering system wiring harness of this application; Figure 3 This is a schematic diagram of the B-end connector of the automotive power steering system wiring harness of this application; Figure 4 This is a front view of the B-end connector of the automotive power steering system wiring harness of this application.

[0027] Explanation of reference numerals in the attached figures: 1. A-end wire sleeve; 2. B-end connector; 3. Sleeve; 4. Locking structure. Detailed Implementation

[0028] The present application will be further described in detail below with reference to the embodiments.

[0029] The following are some of the sources and specifications of the raw materials used in this application. The raw materials used in the preparation examples and embodiments of this application can all be obtained commercially, including but not limited to the following models and manufacturers of raw materials. Raw materials with equivalent performance can also be used: Hydroxyl-terminated polymethylvinylsiloxane-polydimethylsiloxane copolymer: Nanjing Sisibo Organosilicon, SiSiB® OF6051; Oligomeric siloxanes containing vinyl, propyl, and ethoxy groups: Evonik Degussa, Dynasylan® 6598; Insulating filler: alumina, particle size 50-100nm; Core wire: Red wire - WIRE AESSX-0.3f, Sumitomo Electric Industries; Black wire - WIRE AESSX-0.3f, Sumitomo Electric Industries; Blue wire - WIRE AESSX-0.3f, Sumitomo Electric Industries; Yellow wire - WIRE AESSX-0.3F, Sumitomo Electric Industries; White wire - WIRE AESSX-0.3f, Sumitomo Electric Industries; Green wire - WIRE AESSX-0.3f, Sumitomo Electric Industries; Terminal: Terminal 1-TERMINAL, 0.22-0.5mm 2 Gold-plated end, TYCO P / N 1123343-2, quantity 4 pieces; Terminal 2-TERMINAL,0.22-0.5mm 2 Tin-plated end, TYCO P / N 1123343-1, quantity 2; Sleeve: PVC tubing, UL / CSA, -40℃ to 105℃, black, ID: 8.0mm; A-end cable sleeve: CAP, EPDM wire sheath, black; Rubber protective coil: EPDM protective coil, 1mm thick; B-end connector: HOUSING, 2x4PIN, black, TYCO PIN 1379659-1.

[0030] Example Example 1

[0031] Example 1 discloses a manufacturing process for a wiring harness of an automotive power steering system, the specific steps of which are as follows: S1. Wire Cutting and Stripping: Select 6 core wires (including red, black, blue, yellow, white, and green wires), and cut each core wire to the required length of 346mm. Then, partially strip the insulation from end A of each core wire, with a total stripping length of 13mm, of which 4mm is partially stripped (only 4mm of insulation is removed from the end, leaving the remaining 9mm of insulation). Fully strip the insulation from end B of each core wire, with a stripping length of 3.25mm. S2, B-end crimping terminal: Select a suitable cold-pressed terminal, insert the stripped conductor of the B end of the core wire into the terminal crimping area, and crimp it using a crimping device to ensure that the terminal and conductor are tightly crimped without loosening; among them, the red wire, black wire, blue wire and yellow wire are crimped to terminal 1, and the green wire and white wire are crimped to terminal 2; S3. Assembly of A-end sleeve 1: Select the corresponding specification of A-end sleeve 1, and put the rubber protective coil into the 6 connecting holes of A-end sleeve 1 respectively. Use an awl to open the rubber protective coil, and then insert the A ends of the 6 core wires into the rubber protective coil in sequence, ensuring that the A ends of the core wires extend a certain distance beyond the outside of the A-end sleeve (the extension distance in this embodiment is 10mm), so that the half-stripped part is completely exposed. S4. Cutting and fitting of sleeve 3: Select PVC sleeve and cut it to a length of 270mm. Fit sleeve 3 into the core wire B end to ensure that sleeve 3 completely covers the middle area of ​​multiple core wires. S5, B-end connector 2 assembly: (1) Preparation of insulating adhesive: Weigh 0.7 kg of hydroxyl-terminated polymethylvinylsiloxane-polydimethylsiloxane copolymer, 0.08 kg of isocyanate mixture (composed of octadecyl isocyanate and isoflurane diisocyanate in a weight ratio of 3:1), 0.2 kg of alumina as insulating filler, 0.03 kg of methyltrimethoxysilane as crosslinking agent and 0.005 kg of dibutyltin dilaurate as catalyst, mix and stir evenly to obtain insulating adhesive; (2) Inject 0.2g of insulating glue into each of the 6 connecting slots of connector 2 (connector with locking structure 4) at end B, ensuring that the bottom of the connecting slots is evenly covered with insulating glue; (3) Insert the B end of the crimped terminal into the corresponding connecting slot in sequence, until the terminal and the contact point of the connecting slot are completely in contact; (4) The locking structure 4 of the fastening connector is used to mechanically lock and fix the core wire; Curing process: Place the assembled wire harness into a curing chamber and bake at 90℃ for 20 minutes; after taking it out, place it in a normal temperature environment of 25℃ and 50%RH for 12 hours to complete deep curing with the help of ambient humidity. S6. Inspection: Inspect the cured wiring harness. If the inspection is passed, the automotive power steering system wiring harness is obtained. (Refer to...) Figures 1-4 .

[0032] Example 2

[0033] The difference between Example 2 and Example 1 lies in the different parameters used in each step of the preparation process, as detailed below: S1. Wire Cutting and Stripping: Select 6 core wires (including red, black, blue, yellow, white, and green wires), and cut each core wire to the required length of 346mm. Then, partially strip the insulation from end A of each core wire, with a total stripping length of 13mm, of which 4mm is partially stripped (only 4mm of insulation is removed from the end, leaving the remaining 9mm of insulation). Fully strip the insulation from end B of each core wire, with a stripping length of 3.25mm. S2, B-end crimping terminal: Select a suitable cold-pressed terminal, insert the stripped conductor of the B end of the core wire into the terminal crimping area, and crimp it using a crimping device to ensure that the terminal and conductor are tightly crimped without loosening; among them, the red wire, black wire, blue wire and yellow wire are crimped to terminal 1, and the green wire and white wire are crimped to terminal 2; S3, Sleeve 3 Cutting and Fitting: Select PVC sleeve and cut it to a length of 260mm. Fit sleeve 3 from end B of core wire, ensuring that sleeve 3 completely covers the middle area of ​​multiple core wires. S4. Assembly of A-end sleeve 1: Select the corresponding specification of A-end sleeve 1, and put the rubber protective coil into the 6 connecting holes of A-end sleeve 1 respectively. Use an awl to open the rubber protective coil, and then insert the A ends of the 6 core wires into the rubber protective coil in sequence, ensuring that the A ends of the core wires extend a certain distance outside the A-end sleeve (the extension distance in this embodiment is 15mm), so that the half-stripped part is completely exposed. S5, B-end connector 2 assembly: (1) Preparation of insulating adhesive: Weigh 0.75 kg of hydroxyl-terminated polymethylvinylsiloxane-polydimethylsiloxane copolymer, 0.1 kg of isocyanate mixture (composed of hexamethylene diisocyanate and isoflurone diisocyanate in a weight ratio of 2:1), 0.25 kg of alumina as insulating filler, 0.04 kg of methyltrimethoxysilane as crosslinking agent and 0.008 kg of dibutyltin dilaurate as catalyst, mix and stir evenly to obtain insulating adhesive; (2) Inject 0.3g of insulating glue into each of the 6 connecting slots of connector 2 (connector with locking structure 4) at end B, ensuring that the bottom of the connecting slots is evenly covered with insulating glue; (3) Insert the B end of the crimped terminal into the corresponding connecting slot in sequence, until the terminal and the contact point of the connecting slot are completely in contact; (4) The locking structure 4 of the fastening connector is used to mechanically lock and fix the core wire; Curing process: Place the assembled wire harness into a curing chamber and bake at 80℃ for 30 minutes; after taking it out, place it in a normal temperature environment of 25℃ and 50%RH for 24 hours to complete deep curing with the help of ambient humidity. S6. Inspection: The cured wiring harness is inspected. If the inspection is qualified, the automotive power steering system wiring harness is obtained.

[0034] Example 3

[0035] The difference between Example 3 and Example 1 lies in the different parameters used in each step of the preparation process, as detailed below: S1. Wire Cutting and Stripping: Select 6 core wires (including red, black, blue, yellow, white, and green wires), and cut each core wire to the required length of 346mm. Then, partially strip the insulation from end A of each core wire, with a total stripping length of 13mm, of which 4mm is partially stripped (only 4mm of insulation is removed from the end, leaving the remaining 9mm of insulation). Fully strip the insulation from end B of each core wire, with a stripping length of 3.25mm. S2, B-end crimping terminal: Select a suitable cold-pressed terminal, insert the stripped conductor of the B end of the core wire into the terminal crimping area, and crimp it using a crimping device to ensure that the terminal and conductor are tightly crimped without loosening; among them, the red wire, black wire, blue wire and yellow wire are crimped to terminal 1, and the green wire and white wire are crimped to terminal 2; S3. Assembly of A-end sleeve 1: Select the corresponding specification of A-end sleeve 1, and put the rubber protective coil into the 6 connecting holes of A-end sleeve 1 respectively. Use an awl to open the rubber protective coil, and then insert the A ends of the 6 core wires into the rubber protective coil in sequence, ensuring that the A ends of the core wires extend a certain distance beyond the outside of the A-end sleeve (the extension distance in this embodiment is 18mm), so that the half-stripped part is completely exposed. S4. Cutting and fitting of sleeve 3: Select PVC sleeve and cut it to a length of 275mm. Fit sleeve 3 into the core wire B end to ensure that sleeve 3 completely covers the middle area of ​​multiple core wires. S5, B-end connector 2 assembly: (1) Preparation of insulating adhesive: Weigh 0.8 kg of hydroxyl-terminated polymethylvinylsiloxane-polydimethylsiloxane copolymer, 0.12 kg of isocyanate mixture (composed of octadecyl isocyanate and isoflurane diisocyanate in a weight ratio of 1:1), 0.3 kg of alumina as insulating filler, 0.05 kg of methyltrimethoxysilane as crosslinking agent and 0.01 kg of dibutyltin dilaurate as catalyst, mix and stir evenly to obtain insulating adhesive; (2) Inject 0.25g of insulating glue into each of the 6 connecting slots of connector 2 (connector with locking structure 4) at end B, ensuring that the bottom of the connecting slots is evenly covered with insulating glue; (3) Insert the B end of the crimped terminal into the corresponding connecting slot in sequence, until the terminal and the contact point of the connecting slot are completely in contact; (4) The locking structure 4 of the fastening connector is used to mechanically lock and fix the core wire; Curing process: Place the assembled wire harness into a curing chamber and bake at 85℃ for 35 minutes; after taking it out, place it in a normal temperature environment of 25℃ and 50%RH for 18 hours to complete deep curing with the help of ambient humidity. S6. Inspection: The cured wiring harness is inspected. If the inspection is qualified, the automotive power steering system wiring harness is obtained.

[0036] Example 4

[0037] The difference between Example 4 and Example 1 is that the isocyanate mixture consists of octadecyl isocyanate and N-(p-maleimide phenyl) isocyanate in a weight ratio of 3:1, while the rest is the same as in Example 1.

[0038] Example 5

[0039] The difference between Example 5 and Example 1 is that the isocyanate mixture consists of octadecyl isocyanate and N-(p-maleimide phenyl) isocyanate in a weight ratio of 5:1, while the rest is the same as in Example 1.

[0040] Example 6

[0041] The difference between Example 6 and Example 4 is that the crosslinking agent is composed of a vinyl, propyl and ethoxy oligosiloxane and a methyltrimethoxysilane in a weight ratio of 1:2, while the rest is the same as in Example 4.

[0042] Example 7

[0043] The difference between Example 7 and Example 4 is that the crosslinking agent is composed of a vinyl, propyl and ethoxy oligosiloxane and a methyltrimethoxysilane in a weight ratio of 1:4, while the rest is the same as in Example 4.

[0044] Example 8

[0045] The difference between Example 8 and Example 1 is that the insulating adhesive is a commercially available epoxy potting compound, Bedef BAE-9231, with a curing time of 80℃ / 2h + 120℃ / 0.5h. The rest is the same as in Example 1.

[0046] Example 9

[0047] The difference between Example 9 and Example 1 is that the hydroxyl-terminated polymethylvinylsiloxane-polydimethylsiloxane copolymer is replaced by an equal amount of hydroxyl-terminated polydimethylsiloxane. The hydroxyl content of the hydroxyl-terminated polydimethylsiloxane is 2-2.5 mol%, and the rest is the same as in Example 1.

[0048] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that insulating glue is not injected into the connector slot of the B-end connector, and assembly is carried out directly. Otherwise, it is the same as Example 1.

[0049] Performance testing The following are performance tests conducted on the automotive power steering system wiring harnesses prepared in Examples 1-9 and Comparative Example 1: Basic performance tests: Using the Roin wire testing machine, the test conditions are: DC voltage 100V. The insulation resistance, conductor resistance and wire harness continuity of the automotive power steering system wiring harness are tested. Among them, the insulation resistance is ≥5MΩ, the conductor resistance is ≤3Ω and the continuity is 100% qualified.

[0050] 2. Insulation stability test The automotive power steering system wiring harness is kept at a constant temperature of -30℃ for 30 minutes, and then at a constant temperature of 80℃ for 30 minutes, with an interval of no more than 5 seconds between them. This constant temperature treatment is repeated 50 times. Then, a drop test is performed at a height of 1m and 50 drops are performed. The change rate of insulation resistance is tested. If it is less than 3%, it is considered qualified. The test results are recorded. 3. Connector stability test The automotive power steering system wiring harness was kept at a constant temperature of -30℃ for 30 minutes, and then at a constant temperature of 100℃ for 30 minutes, with an interval of no more than 5 seconds between the two. This constant temperature treatment was repeated 50 times. Then, a drop test was performed at a height of 1m, with 50 drops. The tensile force (unit: N) of the automotive power steering system wiring harness was tested using a tensile testing machine, and the test results were recorded. The following are the performance test data of the automotive steering wheel power assist system wiring harnesses obtained in Examples 1-9 and Comparative Example 1, as detailed in Table 1 below.

[0051] Table 1. Data sheet of automotive power steering system wiring harnesses obtained in Examples 1-9 and Comparative Example 1

[0052] Based on Examples 1-3 and Comparative Example 1, and referring to Table 1, it can be concluded that injecting insulating adhesive into the connecting groove of the B-end connector can improve the sensitivity and stability of the resulting wire harness, and it is less prone to loosening and detachment during long-term use. In Comparative Example 1, no insulating adhesive was injected. After high and low temperature tests and drop tests, the insulation resistance change rate of the resulting wire harness was 8.25%, significantly higher than that of Example 1, and the tensile strength was significantly reduced.

[0053] Combining Examples 1 and 4-8 with Table 1, it can be concluded that the hydroxyl-terminated polymethylvinylsiloxane-polydimethylsiloxane copolymer, isocyanate polymer, and crosslinking agent compounded with the specific components of this application synergistically improve the sensitivity and stability of the resulting wire harness, and are less prone to loosening and detachment during long-term use. Examples 4-5, compared to Example 1, further optimized the type and proportion of the isocyanate mixture, resulting in a lower insulation resistance change rate and increased tensile strength of the resulting wire harness. Examples 6-7, compared to Example 4, further optimized the type and proportion of the crosslinking agent, resulting in a lower insulation resistance change rate and increased tensile strength of the resulting wire harness. Example 9, compared to Example 1, uses hydroxyl-terminated polydimethylsiloxane instead of the hydroxyl-terminated polymethylvinylsiloxane-polydimethylsiloxane copolymer, resulting in an increased insulation resistance change rate and decreased tensile strength of the resulting wire harness. Example 8, using commercially available insulating adhesive, produced a wire harness with insulation resistance change rate and tensile strength comparable to Examples 1-3. Further verification showed that the insulating adhesive prepared using the specific components of this application can significantly improve the sensitivity and stability of the wire harness, making the wire harness less prone to loosening and falling off during long-term use, which has a significant advantage over conventional commercially available insulating adhesives.

[0054] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A manufacturing process for a wiring harness for an automotive power steering system, characterized in that, Includes the following steps: Cut several core wires to the required length, then partially strip the insulation from end A of several core wires, fully strip the insulation from end B, and crimp a terminal to end B. Assemble the A-end sleeve: According to the assembly requirements, insert the A ends of several core wires into the connection holes of the A-end sleeve in sequence, and each core wire extends a certain distance along the A-end sleeve. Cut the sleeve and place one sleeve around the outside of several core wires along the B end of several core wires. Assembly of B-end connector: According to the assembly requirements, insert the B ends of several core wires into the connection slots of the B-end connector in sequence, test, and obtain the automotive power steering system wiring harness. Before assembling the B-end connector, inject insulating glue into the connection slot of the B-end connector, and then allow several core wires to be inserted into the B-end for curing.

2. The manufacturing process of a wiring harness for an automotive steering wheel power assist system according to claim 1, characterized in that, The insulating adhesive is made from the following raw materials in parts by weight: 70-80 parts of hydroxyl-terminated polymethylvinylsiloxane-polydimethylsiloxane copolymer 8-12 parts of isocyanate mixture 20-30 parts of insulating filler 3-5 parts crosslinking agent Catalyst 0.5-1 part.

3. The manufacturing process of a wiring harness for an automotive steering wheel power assist system according to claim 2, characterized in that, The isocyanate mixture consists of octadecyl isocyanate and N-(p-maleimide phenyl) isocyanate in a weight ratio of (3-5):

1.

4. The manufacturing process of a wiring harness for an automotive steering wheel power assist system according to claim 2, characterized in that, The crosslinking agent is composed of a vinyl, propyl and ethoxy oligomeric siloxane and a methyltrimethoxysilane in a weight ratio of 1:(2-4).

5. The manufacturing process of a wiring harness for an automotive steering wheel power assist system according to claim 1, characterized in that, The total stripped length of the A end of the core wire is 13±1mm, and the half-stripped length is 4±1mm; the stripped length of the B end of the core wire is 3.25±0.25mm.

6. The manufacturing process of a wiring harness for an automotive steering wheel power assist system according to claim 1, characterized in that, Before assembling the A-end sleeve, the rubber protective coil needs to be inserted into the connection hole of the A-end sleeve, then the rubber protective coil is opened and the A end of the core wire is inserted into the rubber protective coil.

7. The manufacturing process of a wiring harness for an automotive steering wheel power assist system according to claim 1, characterized in that, The B-end connector is equipped with a locking structure. After the B-ends of several core wires are inserted into the connection slot, they are locked first and then cured.

8. A wiring harness for an automotive steering wheel power assist system, characterized in that, It is prepared by the manufacturing process of a car steering wheel power assist system wiring harness as described in any one of claims 1-7.

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