A wiper blade

Abstract

The application relates to the technical field of automobile wiper, in particular to a wiper rubber strip, which comprises a rubber strip body, the rubber strip body comprises a mounting part, a connecting part and a wiping part in sequence along the length direction of the rubber strip body; the rubber strip body is made of a low-temperature-resistant rubber composite material, the low-temperature-resistant rubber composite material comprises the following components in parts by weight: 40-60 parts of silicone rubber, 20-35 parts of natural rubber, 10-20 parts of ethylene-propylene-diene rubber, 15-30 parts of a reinforcing agent, 1-3 parts of a vulcanizing agent, 0.5-2 parts of an accelerator, 1-3 parts of an antioxidant and 3-8 parts of a low-temperature plasticizer; the connecting part is provided with a hollow damping cavity extending along the length direction of the rubber strip body. Through the synergistic effect of material modification, a hollow damping structure and surface micro-texture, the rubber strip can keep excellent flexibility in a low-temperature environment, can significantly reduce wiping noise and improve wiping cleanliness, and is suitable for various vehicle wiper systems.

Description

Technical Field

[0001] This invention relates to the field of automotive windshield wiper technology, and in particular to a windshield wiper blade. Background Technology

[0002] Windshield wipers are an important safety component of motor vehicles. They remove rainwater and pollutants through the reciprocating friction between the wiper blade and the windshield, ensuring clear visibility for the driver. The wiper blade, as the core component of the wiper system, directly determines the cleaning effect and lifespan of the wiper.

[0003] The existing wiper blade rubber strips have the following main problems: First, in low-temperature environments, the rubber strips harden, significantly reducing wiping performance. Traditional wiper blades are mostly made of natural rubber. While natural rubber offers good wear resistance and low cost, its weather resistance is poor. When the ambient temperature is low (such as below 7°C), the rubber will harden to varying degrees. Once the rubber strip hardens, it becomes difficult to adhere well to the windshield surface under the pressure of the wiper arm, resulting in incomplete wiping, water streaks, and seriously affecting driving safety. Low temperatures also make the rubber brittle and more prone to cracking.

[0004] Secondly, the rubber wiper blades produce significant wiping noise. During the reciprocating wiping process, the rubber blades undergo a flipping motion, which is particularly noisy when flipping at the limit of their travel. Increasing the wiper arm pressure to improve wiping performance, while allowing the rubber blades to adhere more tightly to the glass, further increases friction and wiping noise. Additionally, as the rubber blades age and harden, they become more prone to bouncing on the glass and generating noise.

[0005] Third, the surface coating has poor durability. To reduce the coefficient of friction, existing technologies often coat the surface of the rubber strip with a graphite coating or a silicon coating. However, graphite coatings contain a large amount of free graphite powder, which is consumed with use and is not durable; silicon coatings generally have poor wear resistance and are relatively expensive. After the coating is worn away, the friction of the rubber strip increases, further worsening the scraping effect and noise problems.

[0006] To address these issues, several technical solutions have been proposed. For example, actively heating the rubber strip by incorporating heating wires or heating pads prevents it from hardening at low temperatures; modifying natural rubber by incorporating silicone to improve weather resistance; and reducing turning noise by adding buffer zones and cushioning protrusions to the rubber strip structure. However, each of these solutions has its own shortcomings: heating solutions require external power, resulting in complex structures and high energy consumption; material modification solutions, while improving low-temperature resistance, have limited impact on the frictional characteristics and scraping efficiency between the rubber strip and glass; and simple structural noise reduction solutions fail to solve the fundamental problem of hardening at low temperatures.

[0007] Application content This invention addresses the technical problems of existing wiper blades, such as hardening in low-temperature winter environments, excessive noise during use, and inadequate wiping. It provides a wiper blade that, through a multi-faceted synergistic design of materials, structure, and surface treatment, simultaneously solves the problems of hardening at low temperatures, wiping noise, and insufficient wiping cleanliness.

[0008] The technical solution of this invention is implemented as follows: A wiper blade includes a blade body, wherein the blade body comprises, in sequence along its length, an mounting portion, a connecting portion, and a wiping portion; The mounting part is used to be fixedly connected to the wiper frame, and the mounting part is provided with steel plate mounting grooves and snap-on mounting grooves on both sides. The wiping part includes a wiping lip, which is used to contact the windshield for wiping. Its features are: The rubber strip body is made of low-temperature resistant rubber composite material, which includes, by weight, 40-60 parts silicone rubber, 20-35 parts natural rubber, 10-20 parts EPDM rubber, 15-30 parts reinforcing agent, 1-3 parts vulcanizing agent, 0.5-2 parts accelerator, 1-3 parts antioxidant, and 3-8 parts low-temperature plasticizer. The connecting part is provided with a hollow damping cavity extending along the length of the rubber strip body. The cross-section of the hollow damping cavity is elliptical, and the major axis of the ellipse is perpendicular to the scraping direction of the rubber strip body. The surface of the scraping lip is provided with a self-lubricating and wear-resistant composite coating. The self-lubricating and wear-resistant composite coating has a double-layer structure, including a bottom layer and a top layer. The bottom layer is a polyurethane resin layer, and the top layer is a composite lubricating layer containing polytetrafluoroethylene particles and graphene particles. The scraping surface of the scraping lip is provided with a microtexture extending along the length of the adhesive strip body. The microtexture consists of multiple spaced micro-grooves with a depth of 10-50 μm, a width of 20-100 μm, and a spacing of 50-200 μm between adjacent micro-grooves.

[0009] Preferably, in the low-temperature resistant rubber composite material, the silicone rubber is methyl vinyl silicone rubber with a vinyl content of 0.1-0.5 mol%, and the natural rubber is epoxidized natural rubber with an epoxidation degree of 10-30 mol%.

[0010] Preferably, the low-temperature plasticizer is one or more of dioctyl sebacate, dioctyl adipate, or dioctyl azelate.

[0011] Preferably, the reinforcing agent is fumed silica with a specific surface area of ​​150-300 m². 2 / g.

[0012] Preferably, the hollow damping cavity is filled with a damping material, which is a silicone gel or a polyurethane gel.

[0013] Preferably, the thickness of the bottom layer of the self-lubricating wear-resistant composite coating is 5-15 μm, and the thickness of the top layer is 10-30 μm.

[0014] Preferably, the cross-section of the micro-groove is V-shaped, U-shaped, or trapezoidal.

[0015] Preferably, the micro-grooves are arranged periodically on the scraping surface of the scraping lip, and the depth of the micro-grooves gradually increases from both ends to the middle in each cycle.

[0016] A method for preparing the wiper blade rubber strip as described above includes the following steps: Step 1: Mix silicone rubber, natural rubber, EPDM rubber, reinforcing agent, antioxidant and low temperature plasticizer in an internal mixer according to the formula, control the temperature at 80-120℃ and the time at 10-20 minutes to obtain masterbatch. Step 2: Cool the masterbatch to 40-60℃, add vulcanizing agent and accelerator, and mix evenly in a thin pass on a two-roll mill. Step 3: The mixed rubber compound is extruded through an extruder and the extrusion temperature is controlled at 60-90℃ to obtain a semi-finished rubber strip body with a hollow damping cavity. The hollow damping cavity is a through-hole structure with both ends through. Step 4: Perform vulcanization treatment on the semi-finished rubber strip body. The vulcanization temperature is 160-190℃ and the vulcanization time is 5-15 minutes. Step 5: Fill the hollow damping cavity with damping material. Specifically, this includes: injecting liquid damping material into the hollow damping cavity from one end of the rubber strip until the liquid damping material flows out from the other end without any air bubbles. Then, seal both ends to allow the liquid damping material to solidify in the hollow damping cavity and form a solid damping material. Step 6: The micro-grooves are formed on the scraping surface of the lip using laser processing; Step 7: Apply a polyurethane resin base layer and a composite lubricating layer containing polytetrafluoroethylene particles and graphene particles to the surface of the scraping lip in sequence, and obtain the finished product after curing.

[0017] Preferably, in step five, the liquid damping material is a two-component addition-type silica gel, which is mixed at a mass ratio of A:B=1:1 and injected into the hollow damping cavity, and cured at room temperature for 24 hours; the damping material is silica gel.

[0018] Preferably, in step five, the liquid damping material is a mixture of polyurethane prepolymer and curing agent, which is injected into the hollow damping cavity and cured at 60°C for 6 hours; the damping material is polyurethane gel.

[0019] Preferably, in step five, the injection pressure is controlled at 0.2-0.5 MPa, and the injection speed is 0.3-0.8 mL / s; the sealing is achieved by inserting an uncured rubber strip into the port and sealing it with rubber adhesive.

[0020] Preferably, in step five, before injecting the damping material, the port of the hollow damping cavity is pre-treated by cutting off 1-3mm from both ends of the rubber strip to expose a clean inner cavity port; the liquid damping material is degassed under vacuum for 5-15 minutes before injection.

[0021] Preferably, in step six, the laser processing uses a femtosecond laser, picosecond laser, or nanosecond laser with a laser power of 5-20W and a scanning speed of 100-800mm / s; protective gas is blown into the processing area during the laser processing.

[0022] Preferably, in step seven, the coating of the bottom layer is carried out by spraying or dip-coating, and after coating, it is baked at 70-100℃ for 20-60 minutes to form a polyurethane resin bottom layer with a thickness of 5-15μm; the coating of the top layer is carried out by dip-coating or spraying, and after coating, it is cured at 100-130℃ for 30-60 minutes to form a composite lubricating surface layer with a thickness of 10-30μm.

[0023] By adopting the above technical solution, the beneficial effects of the present invention are as follows: 1. This invention employs a ternary composite system of silicone rubber, natural rubber, and EPDM rubber, combined with a low-temperature plasticizer, to significantly reduce the glass transition temperature of the rubber strip while maintaining its elasticity. Silicone rubber itself has excellent low-temperature resistance, epoxidized natural rubber improves its compatibility with silicone rubber, and EPDM rubber further enhances its weather resistance. The synergistic effect of these three components allows the rubber strip to maintain good flexibility and elasticity even at -40℃, fundamentally solving the problem of rubber strips hardening in winter.

[0024] 2. This invention incorporates an elliptical hollow damping cavity at the connection point. This structure absorbs and buffers the vibration energy of the scraping lip during the edge-flanging process of the rubber strip, reducing the transmission of vibration to the mounting part. The elliptical cross-section design of the hollow damping cavity provides excellent deformation capacity and resilience under stress in different directions, effectively reducing noise during the scraping process. The noise reduction effect is even more significant when the damping cavity is further filled with damping material.

[0025] 3. This invention features a double-layer self-lubricating and wear-resistant composite coating on the surface of the scraping lip. The bottom layer of polyurethane resin provides excellent adhesion, while the top layer of polytetrafluoroethylene and graphene composite lubricating layer exhibits an extremely low coefficient of friction and excellent wear resistance. Simultaneously, the micro-texture on the scraping surface can store trace amounts of lubricating medium, which is continuously released during scraping, forming a stable lubricating film and reducing dry friction between the rubber strip and the glass. The gradually varying depth of the micro-grooves ensures that the rubber strip maintains good lubrication at different scraping angles, guaranteeing a clean and durable scraping experience.

[0026] 4. The material modification, structural design, and surface treatment of this invention work synergistically: the low-temperature resistant material ensures the flexibility of the rubber strip at low temperatures, providing a foundation for noise reduction and effective scraping; the hollow damping cavity reduces noise caused by material hardening and increased friction; the self-lubricating coating and micro-texture reduce frictional resistance, further reducing noise and improving scraping performance. The synergistic effect of these three elements achieves a comprehensive effect of "not hardening at low temperatures, silent scraping, and long-lasting cleanliness," overcoming the limitations of single improvement solutions in existing technologies. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the cross-sectional structure of the wiper blade of the present invention; Figure 2 This is a partially enlarged schematic diagram of the microtexture of the scraping surface on the lip edge of the present invention; Figure 3 This is a perspective view of the wiper blade of the present invention; Figure 4 This is a front view of the wiper blade of the present invention; Figure 5 This is a bottom view of the wiper blade of the present invention.

[0029] The annotations in the attached figures are explained as follows: 1. Mounting section; 11. Steel plate mounting groove; 12. Clip mounting groove; 2. Connecting section; 21. Hollow damping cavity; 22. Damping material; 3. Scraping section; 31. Scraping lip; 32. Micro groove; 4. Self-lubricating wear-resistant composite coating; 41. Bottom layer; 42. Top layer. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1: like Figures 1-5 As shown, a wiper blade includes a blade body, which includes a mounting part 1, a connecting part 2, and a wiping part 3 along its length. The mounting part 1 is used to fix and connect with the wiper frame, and steel plate mounting grooves 11 and snap-fit ​​mounting grooves 12 are provided on opposite sides of the mounting part 1. The wiping part 3 includes a wiping lip 31, which is used to contact the windshield for wiping.

[0032] The rubber strip body is made of low-temperature resistant rubber composite material, by weight: 50 parts methyl vinyl silicone rubber (vinyl content 0.3 mol%), 28 parts epoxidized natural rubber (epoxidation degree 20 mol%), 15 parts EPDM rubber, and fumed silica (specific surface area 200 m²). 2 22 parts ( / g), 1.8 parts vulcanizing agent (bis(2,5-dimethyl-2,5-di(tert-butylperoxy)hexane), 1 part accelerator (tetramethylthiuram disulfide, TMTD), 1.5 parts antioxidant (2,2,4-trimethyl-1,2-dihydroquinoline polymer, antioxidant RD), and 5 parts dioctyl sebacate.

[0033] The connecting part 2 is provided with a hollow damping cavity 21 extending along the length of the rubber strip body. The cross-section of the hollow damping cavity 21 is elliptical, with a major axis of 3 mm and a minor axis of 1.5 mm. The direction of the major axis of the ellipse is perpendicular to the scraping direction of the rubber strip body. The hollow damping cavity 21 is filled with silicone gel damping material 22. The silicone gel damping material 22 is prepared by mixing a two-component addition-type silicone gel (component A is vinyl-containing polydimethylsiloxane, component B is hydrogen-containing silicone oil crosslinking agent, and the platinum catalyst content is 0.5% of the mass of component A) at a mass ratio of A:B=1:1, injecting it into the hollow damping cavity 21, and allowing it to cure at room temperature for 24 hours.

[0034] The surface of the scraping lip 31 is provided with a self-lubricating and wear-resistant composite coating 4. The self-lubricating and wear-resistant composite coating 4 has a double-layer structure, including a bottom layer 41 and a top layer 42. The bottom layer 41 is a polyurethane resin layer with a thickness of 10μm. The top layer 42 is a composite lubricating layer containing polytetrafluoroethylene particles (particle size 2μm) and graphene particles (sheet size 1μm). The mass ratio of polytetrafluoroethylene particles to graphene particles in the top layer is 8:2, and the thickness of the top layer is 20μm.

[0035] The scraping surface of the scraping lip 31 is formed with a femtosecond laser to create V-shaped microgrooves 32. The depth of each microgroove 32 is 30 μm, the width is 50 μm, and the spacing between adjacent microgrooves is 100 μm. The microgrooves 32 are arranged periodically on the scraping surface of the scraping lip 31, with each period being 5 mm long. Within each period, the depth of the microgrooves 32 gradually increases from both ends towards the middle, with a depth of 15 μm at both ends and 45 μm in the middle.

[0036] The preparation method of the wiper blade rubber strip in this embodiment is as follows: Step 1: Mixing process The following components are mixed according to the specified ratio: 50 parts methyl vinyl silicone rubber (vinyl content 0.3 mol%), 28 parts epoxidized natural rubber (epoxidation degree 20 mol%), 15 parts ethylene propylene diene monomer (EPDM) rubber, and fumed silica (specific surface area 200 m²). 2 22 parts of (g) antioxidant RD, 1.5 parts of dioctyl sebacate, and 5 parts of dioctyl sebacate were added to an internal mixer and mixed. The rotor speed of the internal mixer was 50 r / min, the mixing temperature was 100℃, and the mixing time was 15 minutes to obtain the masterbatch. During the mixing process, the cooling water flow rate of the internal mixer was controlled to ensure that the mixing temperature did not exceed 120℃ to prevent premature cross-linking of the rubber.

[0037] Step 2, sulfur addition process: The masterbatch obtained in step one was cooled to 50°C on a two-roll mill. 1.8 parts of the vulcanizing agent bis(2,5-dimethyl-2,5-di(tert-butylperoxy)hexane) and 1 part of the accelerator TMTD (tetramethylthiuram disulfide) were added, and the mixture was then subjected to a thin-pass mixing process on the two-roll mill. The mill roll gap was adjusted to 0.5 mm, the front roll speed was 18 r / min, the rear roll speed was 15 r / min, and the mixture was passed through the mill 6 times to ensure thorough and uniform dispersion of the vulcanizing agent and accelerator in the rubber compound. After the thin-pass mixing was completed, the roll gap was adjusted to 2 mm, and the rubber was sheeted for later use.

[0038] Step 3: Extrusion molding process: The compound obtained in step two is fed into a single-screw extruder for extrusion molding. The extruder screw has a diameter of 60 mm, a length-to-diameter ratio of 12:1, and a screw speed of 20 r / min. The extruder has three heating zones along the screw direction: the first zone has a temperature of 60℃, the second zone has a temperature of 75℃, and the third zone has a temperature of 85℃. The extruder die temperature is 90℃. A core mold is located in the extrusion die corresponding to the hollow damping cavity 21. The core mold is fixed inside the die by three cross-shaped support ribs, each 0.8 mm wide. During extrusion, the rubber compound flows around the core mold, forming a semi-finished rubber strip with an elliptical hollow damping cavity 21. The extruded semi-finished product is immediately cooled in a water-cooling shaping tank, which is 2 m long and the water temperature is controlled at 25℃. The cooled semi-finished product is then wound up by a traction machine at a speed of 3 m / min. At this point, the hollow damping cavity 21 has a through-hole structure with both ends, facilitating subsequent rubber injection.

[0039] Step 4: Vulcanization process: The semi-finished rubber strip obtained in step three undergoes a two-stage vulcanization process. The first stage of vulcanization is carried out on a flat vulcanizing machine at a temperature of 165℃, a pressure of 12MPa, and a time of 6 minutes. The second stage of vulcanization is carried out in a hot air oven at a temperature of 185℃ and a time of 10 minutes. The interval between the two stages of vulcanization should not exceed 30 minutes. After vulcanization, the strip is allowed to cool naturally to room temperature. This vulcanization temperature (165-185℃) is much higher than the curing temperature of the subsequent damping material (silicone gel) (room temperature to 60℃). Therefore, the damping material must be filled only after vulcanization is complete and the strip has cooled to prevent high temperatures from damaging the structure of the damping material.

[0040] Step 5: Damping material filling process: Place the cooled and vulcanized rubber strip body flat on the worktable.

[0041] First, pre-process the two ends of the hollow damping cavity 21: cut off 2mm from each end of the rubber strip with a cutter to expose the clean, elliptical inner cavity port without rubber burrs blocking it.

[0042] Next, the damping material is prepared: Component A (containing vinyl polydimethylsiloxane) and component B (containing hydrogen silicone oil crosslinking agent, with platinum catalyst content of 0.5% of component A's mass) of the two-component addition-type silicone gel are mixed evenly in a vacuum mixer at a mass ratio of A:B=1:1, and degassed under a vacuum of -0.08MPa for 10 minutes until no visible bubbles are present in the mixture.

[0043] Next, the silicone gel is filled: using a precision metering dispensing machine, the degassed liquid silicone gel mixture is injected into the hollow damping cavity 21 through the elliptical inner cavity port at one end of the silicone strip using a dispensing needle (1.2 mm inner diameter). During the dispensing process, the other end of the silicone strip is tilted slightly upwards at 5°-10° (to facilitate gas expulsion), the dispensing pressure is controlled at 0.3-0.5 MPa, and the dispensing speed is 0.5 mL / s. When the liquid silicone gel flows out continuously in a linear stream from the other end port without any air bubbles, it indicates that the hollow damping cavity 21 has been completely filled, and the dispensing is stopped immediately.

[0044] Finally, sealing and curing are performed: Uncured rubber strips (2mm wide, 1mm thick) of the same material as the rubber strip body are inserted into both ends of the port, and a quick-drying rubber adhesive (cyanoacrylate adhesive) is applied along the port seams to seal and prevent leakage of the liquid silicone gel before curing. The sealed rubber strips are placed horizontally in a constant temperature chamber and allowed to cure at room temperature (23℃±2℃) for 24 hours, allowing the injected liquid silicone gel to crosslink and form silicone gel damping material 22. After curing, excess gel and sealing rubber strips overflowing from both ends are removed with a sharp blade, ensuring smooth and flat end faces of the rubber strip.

[0045] Step Six: Laser Processing of Microtextures A femtosecond laser with a wavelength of 800 nm was used to laser process the scraping surface of the scraping lip 31 of the adhesive strip body after the damping material was filled in step five, forming micro-grooves 32. The femtosecond laser had a pulse width of 120 femtoseconds, a repetition frequency of 1000 kHz, a laser power of 8 W, and a scanning speed of 300 mm / s. The laser focus position was controlled by a three-dimensional galvanometer, and the laser was scanned line by line on the scraping surface according to a preset periodic depth change trajectory. Each line was 50 μm wide, and the line spacing was 100 μm. During the laser processing, high-purity nitrogen (99.999% purity) was continuously blown into the processing area at a flow rate of 5 L / min to prevent oxidation of the processing area and to remove processing debris. After processing, the adhesive strip was ultrasonically cleaned in anhydrous ethanol for 5 minutes to remove residual debris, and then dried in a 60°C oven for 30 minutes.

[0046] Step 7: Coating application process: First, the base layer 41 is coated: Thermoplastic polyurethane (TPU) particles are dissolved in N,N-dimethylformamide (DMF) to prepare a polyurethane solution with a solid content of 20wt%. This solution is then uniformly sprayed onto the surface of the scraper lip 31 using an air spraying method. The spraying pressure is 0.3MPa, the spraying distance is 15cm, and the spraying is repeated twice. After spraying, the mixture is baked in an oven at 80℃ for 40 minutes to allow the solvent to fully evaporate, forming a polyurethane resin base layer with a thickness of 10μm.

[0047] Then, the top layer 42 is coated: polytetrafluoroethylene microparticles (average particle size 2 μm) and graphene microparticles (average sheet size 1 μm) are dispersed in anhydrous ethanol at a mass ratio of 8:2, and polyvinyl butyral (PVB) is added as a binder at 1.5% of the total mass of the dispersion. The dispersion is carried out using a high-speed mixer at 2000 r / min for 60 minutes to form a composite lubricating layer dispersion with a solid content of 8 wt%. The adhesive strip coated with the bottom layer is immersed in the above dispersion using the dip-pull method for 15 seconds, and then vertically pulled out of the liquid surface at a speed of 120 mm / min. After the pull-out is completed, it is allowed to stand at room temperature for 10 minutes to allow the solvent to evaporate initially, and then placed in an oven at 120°C for curing for 45 minutes to form a composite lubricating layer with a thickness of 20 μm.

[0048] Step 8: Post-processing procedures: The finished product obtained in step seven is left at room temperature for 24 hours to allow the coating to fully cure and stabilize. Then, visual inspection and dimensional inspection are carried out. Once qualified, it is packaged and stored.

[0049] Example 2: The difference between this embodiment and Embodiment 1 is that: The formulations of low-temperature resistant rubber composite materials vary, and by weight: 40 parts methyl vinyl silicone rubber (vinyl content 0.1 mol%), 35 parts epoxidized natural rubber (epoxidation degree 30 mol%), 20 parts ethylene propylene diene monomer (EPDM) rubber, and fumed silica (specific surface area 300 m² / g). 2 30 parts of dicumyl peroxide (DCP), 2.5 parts of accelerator (dibenzothiazole disulfide, MBTS), 1.5 parts of antioxidant (N-isopropyl-N'-phenyl-p-phenylenediamine, antioxidant 4010NA), and 8 parts of dioctyl adipate.

[0050] The hollow damping cavity 21 is not filled with damping material and remains hollow.

[0051] The cross-section of the microgroove 32 is U-shaped, with a depth of 50μm and a width of 100μm. The spacing between adjacent microgrooves is 200μm. The length of each period in the periodic change is 8mm, the depth at both ends is 20μm, and the depth in the middle is 50μm.

[0052] In step three, the temperatures of each heating zone of the extruder are 65℃, 80℃, and 90℃, respectively, and the die head temperature is 95℃.

[0053] Step four involves a single-stage vulcanization process: performed on a flat vulcanizing machine at a temperature of 175°C, a pressure of 10 MPa, and a time of 12 minutes.

[0054] In step six, the laser processing uses a nanosecond laser with a wavelength of 1064nm, a pulse width of 10ns, a repetition frequency of 500kHz, a laser power of 12W, and a scanning speed of 500mm / s.

[0055] Example 3: The difference between this embodiment and Embodiment 1 is that: The formulations of low-temperature resistant rubber composite materials vary, and by weight: 60 parts methyl vinyl silicone rubber (vinyl content 0.5 mol%), 20 parts epoxidized natural rubber (epoxidation degree 10 mol%), 10 parts ethylene propylene diene monomer (EPDM) rubber, and fumed silica (specific surface area 150 m²). 2 15 parts of ( / g) vulcanizing agent (bis(25)) 1.2 parts, accelerator (zinc dibutyl dithiocarbamate, ZDBC) 0.8 parts, antioxidant RD 1.2 parts, and dioctyl azelate 4 parts.

[0056] The hollow damping cavity 21 is filled with polyurethane gel damping material 22, which is prepared by the following method: polyether polyol (hydroxyl value of 56 mg KOH / g) and toluene diisocyanate (TDI) are mixed at an NCO / OH molar ratio of 1.2:1. Triethylenediamine catalyst (0.5% by mass of the prepolymer) and dioctyl phthalate plasticizer (15% by mass) are added, and the mixture is stirred at high speed under vacuum for 8 minutes to remove bubbles. The injection pressure is controlled at 0.2-0.4 MPa, and the injection speed is 0.3 mL / s. After sealing, the gel strip cannot be cured at room temperature; it must be placed in a constant temperature oven at 60°C for 6 hours to allow the polyurethane prepolymer to fully crosslink and form a gel. After curing, excess material at both ends is removed.

[0057] The cross-section of the micro-groove 32 is trapezoidal, with a depth of 15μm and a width of 30μm. The spacing between adjacent micro-grooves is 60μm. No periodic depth variation is used, and the groove depth remains consistent.

[0058] Step four involves a single-stage vulcanization process: performed on a flat vulcanizing machine at a temperature of 180°C, a pressure of 8 MPa, and a time of 8 minutes.

[0059] In step six, the laser processing uses a picosecond laser with a wavelength of 532nm, a pulse width of 15ps, a repetition frequency of 800kHz, a laser power of 6W, and a scanning speed of 200mm / s.

[0060] In step six, the bottom layer thickness is 5 μm and the top layer thickness is 12 μm. The mass ratio of polytetrafluoroethylene particles to graphene particles in the top layer is 9:1, and the curing conditions after the top layer is applied are 110°C for 60 minutes.

[0061] Example 4: The difference between this embodiment and Embodiment 1 is that: In the formulation of the low-temperature resistant rubber composite material, the low-temperature plasticizer is a mixture of dioctyl sebacate and dioctyl adipate in a 1:1 mass ratio, with a total amount of 6 parts.

[0062] The major axis of the ellipse of the hollow damping cavity 21 is 4mm, and the minor axis is 2mm.

[0063] The V-groove of the micro-groove 32 has an angle of 60°, a depth of 40μm, a width of 80μm, and a spacing of 150μm between adjacent micro-grooves. In the periodic depth variation, each period is 10mm long, with a depth of 10μm at both ends and 40μm in the middle, and the depth variation gradually follows a sine curve.

[0064] In step seven, the base coat is applied using the dip-coating method. The adhesive strip is immersed in a polyurethane solution with a solid content of 15 wt% for 30 seconds, and the lifting speed is 80 mm / min. The curing conditions are baking at 90℃ for 50 minutes. The top coat is applied using the air spraying method. The composite lubricating layer dispersion (solid content 10 wt%) is sprayed three times at a pressure of 0.4 MPa and a distance of 12 cm, with a 5-minute interval between each spray. The curing conditions are curing at 130℃ for 30 minutes.

[0065] To verify the technical effects of the present invention, the following comparative examples are provided: Comparative Example 1: Commercially available natural rubber wiper blades (Brand: Bosch, Model: Suitable for universal U-type connectors).

[0066] Comparative Example 2: Commercially available silicone rubber wiper blades (brand: PIAA, model: silicone coated wiper blades).

[0067] Comparative Example 3: A composite rubber strip modified by blending natural rubber and silicone rubber (prepared according to the formulation of Example 1 in Chinese Patent Application CN202311227038).

[0068] Comparative Example 4: The low-temperature resistant rubber composite material formulation of Example 1 of the present invention was used, but no hollow damping cavity was provided, no surface micro-texturing was performed, and no self-lubricating wear-resistant composite coating was applied (i.e., only a solid rubber strip of the material of the present invention).

[0069] The rubber strips of Examples 1-4 and Comparative Examples 1-4 were respectively installed on the same type of wiper frame (U-shaped interface, wiper arm pressure of 12N), and performance tests were conducted under the following test conditions: I. Low-temperature hardness change rate test: The tests were conducted according to GB / T 531.1-2008, "Test Methods for Indentation Hardness of Vulcanized Rubber or Thermoplastic Rubber - Part 1: Shore Hardness Tester Method (Shore Hardness)". After each rubber strip sample was conditioned at room temperature (23℃±2℃) for 24 hours, the Shore A hardness value H0 was measured. Then, the samples were placed in a low-temperature test chamber and cooled to -30℃ at a rate of 1℃ / min. After maintaining this temperature for 24 hours, the Shore A hardness value H1 was rapidly measured inside the low-temperature chamber. The rate of change in hardness at low temperature ΔH = (H1-H0) / H0 × 100%. Five samples were tested in each group, and the average value was taken.

[0070] II. Scraping noise test: Following the general principles of tire / road noise testing in ISO 13325:2019 "Tires – Methods for measuring noise", an adaptability test was conducted based on the operating characteristics of the windshield wipers. Wipers with rubber strips installed were mounted on a simulated wiper wiping test bench (equipped with an adjustable speed wiper motor and crank-connecting rod mechanism). The air supply system simulated wind speed conditions at a vehicle speed of 60 km / h. The test was conducted on a dry, clean flat glass surface with a surface temperature of 23℃±2℃. The wiper motor was started and continuously wiped at a frequency of 45 times / minute (one cycle counts as one stroke). A precision noise meter (A-weighted, accuracy ±0.5 dB) was placed 0.5 m from the contact point between the rubber strip and the glass, at a 45° angle to the glass surface, and the maximum noise value was continuously recorded over 60 seconds. Each test was performed three times, and the average value was taken.

[0071] III. Scraping Cleanliness Rating Test: Refer to the test method for wiping cleanliness in QC / T 44-2009 "Automotive Windshield Electric Wipers". Apply a standard test slurry (prepared by mixing ISO 12103-1 standard dust A4 and deionized water at a mass ratio of 1:3) evenly to the surface of a flat glass pane, controlling the application amount to 20 g / m². 2 The coating thickness was even. The wipers were activated at a frequency of 45 wipes per minute for 5 complete cycles. Five trained rating personnel then visually rated the surface from a 45° angle, 1 meter away from the glass, under a standard light source color matching box (color temperature 6500K). The average of the five ratings was recorded. A 10-point scale was used: 10 points for completely no watermarks, streaks, or residue; 9 points for trace watermarks that did not affect visual clarity; 8 points for slight streaks that did not affect normal vision; 7 points for noticeable streaks or residue that slightly affected vision; 6 points for significant streaks that affected vision; and 5 points or below for severe residue that significantly blurred vision.

[0072] IV. Abrasion resistance test: The test was improved based on GB / T 1689-2014 "Determination of Abrasion Resistance of Vulcanized Rubber (Akron Abrasion Tester Method)" and the actual working conditions of wiper blades. A reciprocating friction testing machine (model: Rtec MFT-3000) was used. The wiping lip of each blade sample was brought into contact with a flat glass plate under a set pressure of 2 N, a friction stroke of 100 mm, and a friction frequency of 3 Hz. The wear endpoint was defined as the number of cycles at which the instantaneous value of the coefficient of friction increased by 50% compared to the initial value (average of the first 100 cycles) or when visible peeling of the coating appeared on the wiping surface of the blade. Three samples were tested in each group, and the average value was taken.

[0073] Summary of test results:

[0074] The test results above show that: 1. Low-temperature hardening resistance: The pure natural rubber strip in Comparative Example 1 showed a hardness change rate of +85% at -30℃, indicating severe hardening and near loss of elasticity. The pure silicone rubber strip in Comparative Example 2 showed a hardness change rate of +15%, performing well. The blended modified rubber strip in Comparative Example 3 showed +35%, indicating some improvement but still not ideal. Comparative Example 4, although using the materials of this invention, had no structural improvements, and its hardness change rate was +10%, essentially equivalent to Example 1. The low-temperature hardness change rates of Examples 1-4 were all controlled between 8% and 12%, demonstrating that the ternary composite rubber formulation of this invention, combined with a low-temperature plasticizer, can significantly reduce the degree of low-temperature hardening of the rubber strips, maintaining good flexibility even under extremely cold conditions of -30℃, fundamentally solving the technical problem of low-temperature hardening of traditional rubber strips.

[0075] 2. Noise Reduction Effect: The scraping noise of Comparative Example 1 reached 78dB; Comparative Example 2 was 65dB; Comparative Example 3 was 68dB; and Comparative Example 4 was 72dB. Example 1 had the lowest noise level at only 52dB, and Example 4 was 53dB. This indicates that the elliptical cross-section design of the hollow damping cavity 21 effectively absorbs and buffers the vibration energy of the scraping lip during the edge-flanging process of the rubber strip, reducing the transmission of vibration to the mounting part. Comparing Example 1 and Comparative Example 4, it can be seen that, under the same material conditions, the noise was reduced by 20dB after setting the hollow damping cavity and micro-textured structure, demonstrating a highly significant noise reduction effect.

[0076] 3. Scraping performance: Example 1 achieved a scraping performance score of 9.8, approaching perfect, while Comparative Example 2, which scored the highest among all comparative examples, only scored 7.5. Example 1 significantly outperformed all other comparative examples. This is due to the synergistic effect of the low-friction characteristics of the self-lubricating wear-resistant composite coating 4 and the oil-retaining lubrication effect of the micro-grooves 32, which allows the rubber strip to maintain a stable lubricating film during scraping, reducing skipping and residual water marks.

[0077] 4. Abrasion resistance and lifespan: Example 1 achieved 800,000 abrasion cycles, which is more than 5 times that of Comparative Example 1 (150,000 cycles) and 2 times that of Comparative Example 2. Even under low-temperature curing, the adhesive strip of this invention maintains durable abrasion resistance and significantly extends its service life.

[0078] The wiper blade of this invention can be widely used in the windshield wiper systems of various automobiles (including passenger cars and commercial vehicles), engineering vehicles (such as the windshields of excavators, loaders, cranes, and other construction machinery), rail vehicles (such as the windshields of high-speed trains and subways), and aircraft. It is particularly suitable for winter use in cold regions (such as Northeast and Northwest my country, and cold regions like Russia and Northern Europe). Components not described in detail herein are prior art.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wiper blade, comprising a blade body, wherein the blade body comprises, sequentially along its length, an mounting portion, a connecting portion, and a wiping portion; the mounting portion is used for fixed connection with a wiper frame, and steel plate mounting grooves and snap-fit ​​mounting grooves are provided on opposite sides of the mounting portion; the wiping portion includes a wiping lip, the wiping lip being used for contacting and wiping the windshield; characterized in that: The rubber strip body is made of low-temperature resistant rubber composite material, which includes, by weight, 40-60 parts silicone rubber, 20-35 parts natural rubber, 10-20 parts EPDM rubber, 15-30 parts reinforcing agent, 1-3 parts vulcanizing agent, 0.5-2 parts accelerator, 1-3 parts antioxidant, and 3-8 parts low-temperature plasticizer. The connecting part is provided with a hollow damping cavity extending along the length of the rubber strip body. The cross-section of the hollow damping cavity is elliptical, and the major axis of the ellipse is perpendicular to the scraping direction of the rubber strip body. The surface of the scraping lip is provided with a self-lubricating and wear-resistant composite coating. The self-lubricating and wear-resistant composite coating has a double-layer structure, including a bottom layer and a top layer. The bottom layer is a polyurethane resin layer, and the top layer is a composite lubricating layer containing polytetrafluoroethylene particles and graphene particles. The scraping surface of the scraping lip is provided with a microtexture extending along the length of the adhesive strip body. The microtexture consists of multiple spaced micro-grooves with a depth of 10-50 μm, a width of 20-100 μm, and a spacing of 50-200 μm between adjacent micro-grooves.

2. The wiper blade according to claim 1, characterized in that: In the low-temperature resistant rubber composite material, the silicone rubber is methyl vinyl silicone rubber with a vinyl content of 0.1-0.5 mol%, and the natural rubber is epoxidized natural rubber with an epoxidation degree of 10-30 mol%.

3. A wiper blade according to claim 1, characterized in that: The low-temperature plasticizer is one or more of dioctyl sebacate, dioctyl adipate, or dioctyl azelate.

4. A wiper blade according to claim 1, characterized in that: The reinforcing agent is fumed silica, with a specific surface area of ​​150-300 m². 2 / g.

5. A wiper blade according to claim 1, characterized in that: The hollow damping cavity is filled with damping material, which is either silicone gel or polyurethane gel.

6. A wiper blade according to claim 1, characterized in that: The self-lubricating and wear-resistant composite coating has a base layer thickness of 5-15 μm and a top layer thickness of 10-30 μm.

7. A wiper blade according to claim 1, characterized in that: The cross-section of the micro-groove is V-shaped, U-shaped, or trapezoidal.

8. A wiper blade according to claim 1, characterized in that: The micro-grooves are arranged periodically on the scraping surface of the scraping lip, and the depth of the micro-grooves gradually increases from both ends to the middle in each cycle.

9. A wiper blade according to any one of claims 1-8, characterized in that, The preparation method of windshield wiper blades includes the following steps: Step 1: Mix silicone rubber, natural rubber, EPDM rubber, reinforcing agent, antioxidant and low temperature plasticizer in an internal mixer according to the formula, control the temperature at 80-120℃ and the time at 10-20 minutes to obtain masterbatch. Step 2: Cool the masterbatch to 40-60℃, add vulcanizing agent and accelerator, and mix evenly in a thin pass on a two-roll mill. Step 3: The mixed rubber compound is extruded through an extruder and the extrusion temperature is controlled at 60-90℃ to obtain a semi-finished rubber strip body with a hollow damping cavity. The hollow damping cavity is a through-hole structure with both ends through. Step 4: Perform vulcanization treatment on the semi-finished rubber strip body. The vulcanization temperature is 160-190℃ and the vulcanization time is 5-15 minutes. Step 5: Fill the hollow damping cavity with damping material. Specifically, this includes: injecting liquid damping material into the hollow damping cavity from one end of the rubber strip until the liquid damping material flows out from the other end without any air bubbles. Then, seal both ends to allow the liquid damping material to solidify in the hollow damping cavity and form a solid damping material. Step 6: The micro-grooves are formed on the scraping surface of the lip using laser processing; Step 7: Apply a polyurethane resin base layer and a composite lubricating layer containing polytetrafluoroethylene particles and graphene particles to the surface of the scraping lip in sequence, and obtain the finished product after curing.

10. A wiper blade according to claim 9, characterized in that: In step five, before the damping material is injected, the port of the hollow damping cavity is pre-treated by cutting off 1-3mm from both ends of the rubber strip to expose a clean inner cavity port; the liquid damping material is degassed under vacuum for 5-15 minutes before injection.

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