Spraying method and device for spiral spring

Abstract

The invention relates to the technical field of spring machining, in particular to a spiral spring spraying method and device.According to the spiral spring spraying method and device, before a spiral spring is sprayed, the spiral spring to be sprayed needs to be stretched, axial stretching is conducted on the basis of geometric parameters of the spring, and the spiral spring to be sprayed is sprayed. The inner wall and the screw pitch gap are forcibly exposed, a shielding blind area caused by traditional fixing and clamping is overcome, and the problem that local corrosion failure is prone to being caused due to the fact that the inner wall and the screw pitch gap of the spring cannot be covered through spraying in a traditional spraying process is solved; and meanwhile, during paint spraying, the spiral spring rotates and axially moves in parallel at the same time, superposition of multi-dimensional movement enables paint mist to cover the curved surface of the spring without dead corners, the defect of uneven thickness of manual spraying is overcome, and the spraying quality of the spiral spring is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of spring processing, and in particular to a spraying method and device for a coil spring. Background Art

[0002] Coil springs are core load-bearing components in automotive suspension, high-speed rail vibration reduction and other fields. In addition to being made of high-strength steel, the surface coating of the springs after production is also crucial. The quality of the surface coating directly affects the corrosion resistance and fatigue life of the coil springs. Usually, coil springs have a hollow structure and a variable pitch. In traditional spraying processes, the inner wall of the spring and the pitch gap are often unable to be covered, which can easily lead to local corrosion failure. Summary of the Invention

[0003] The present application discloses a method and apparatus for spraying a coil spring, so as to solve the problem of incomplete spraying of the coil spring in the coil spring spraying process in the related art, thereby causing local corrosion failure.

[0004] In order to solve the above problems, the present invention provides a method for spraying a coil spring, comprising the following steps: S1, stretching the cleaned coil spring along its axial direction to a target pitch; S2, hanging the stretched spring on a carrier, synchronously performing rotation and axial translation movements in a paint spraying chamber, and applying charged paint mist to the surface of the spring; S3, directing the unabsorbed paint mist to a filtration circulation system through a negative pressure airflow; S4, curing the coating within a specified temperature range.

[0005] Preferably, the following steps are also included before step S1: S01, passing the coil spring through a degreasing station, a water washing station, a phosphating station and a pure water rinsing station in sequence.

[0006] Preferably, the target pitch is 1.2-1.5 times the original pitch of the coil spring.

[0007] Preferably, the gap between adjacent coils of the coil spring after stretching in step S1 is ≥3 mm.

[0008] Preferably, the charged spray is applied in such a manner that the charge-to-mass ratio of the paint particles is 1.2-1.8 mC / kg under a high voltage electric field of -70 kV to -90 kV.

[0009] Preferably, the temperature range during coating curing is 60-80°C.

[0010] In order to solve the above technical problems, the present invention also provides a coil spring spraying device, comprising: a paint spraying tank, a current collecting panel arranged at an angle at the bottom of which; a dynamic stretching module, arranged in the paint spraying tank, comprising a fixed disk and a movable disk with adjustable spacing; a compound motion mechanism, comprising a driving device for driving the fixed disk to rotate and a lifting device for driving the fixed disk to move axially; an electrostatic spraying system, a negative electrode generator being provided at its outlet end; and a closed-loop recovery system, a circulation pipeline connecting the current collecting panel and the spraying system.

[0011] Preferably, the linear actuator of the dynamic stretching module is a hydraulic cylinder or a servo electric cylinder.

[0012] Preferably, the fixing plate comprises a hook.

[0013] Preferably, the closed-loop recovery system includes a cyclone separator and a filter, the inlet of the cyclone separator is communicated with the current collecting panel, and the filter is arranged in the circulation pipeline.

[0014] The technical solution adopted by the present invention can achieve the following beneficial effects: The coil spring spraying method and spraying device adopted by the present invention require stretching the coil spring to be sprayed before spraying. The axial stretching based on the geometric parameters of the spring forces the inner wall and the pitch gap to be exposed, thereby overcoming the blind spots caused by traditional fixed clamping and solving the problem that the spraying in the traditional spraying process cannot cover the inner wall and the pitch gap of the spring, which easily causes local corrosion failure.

[0015] At the same time, when spraying paint, the coil spring rotates and moves axially in parallel at the same time. The superposition of multi-dimensional movement enables the paint mist to cover the spring surface without dead angles, eliminating the uneven thickness defect of manual spraying, and greatly improving the spraying quality of the coil spring. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 is a flow chart of a method for spraying a coil spring disclosed in some embodiments of the present application; Figure 2 is a cross-sectional view of a coil spring spraying device disclosed in some embodiments of the present application; Figure 3 Schematic diagram of a current collecting panel of a coil spring device disclosed in some embodiments of the present application.

[0018] In the picture: 1. Coil spring spraying device; 10. Paint spray booth; 11. Dynamic stretching module; 12. Composite motion mechanism; 13. Electrostatic spraying system; 14. Closed-loop recycling system; 100, current collecting panel; 110, fixed plate; 111, movable plate; 120, driving device; 121, lifting device; 130, negative electrode generator; 131, spray gun; 140, cyclone separator; 141, filter; 142, circulation pipeline; 1000; air hole; 1100, hook. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0020] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0021] Coil springs, as key elastic components in mechanical engineering, are widely used in automotive suspensions, high-speed rail vibration damping systems, and industrial equipment. The quality of their surface coating directly impacts their corrosion resistance and fatigue life. Currently, the industry primarily uses traditional manual spraying and automated electrostatic spraying processes for coil spring surface coating. Manual spraying relies on a single point of application with a handheld spray gun, resulting in poor coating uniformity and low paint utilization. Furthermore, the coating fails to cover the inner wall of the spring and the thread pitch, easily leading to localized corrosion failure.

[0022] The following is combined with Figures 1 to 3 , the spraying method and device for the coil spring provided in this application are described in detail through specific embodiments and their application scenarios.

[0023] Please refer to Figure 1The present invention provides a method for spraying a coil spring, comprising the following steps: S1, stretching the cleaned coil spring along its axial direction to a target pitch; S2, hanging the stretched spring on a carrier, synchronously performing rotation and axial translation movements in a paint spraying chamber, and applying charged paint mist to the surface of the spring; S3, directing the unabsorbed paint mist to a filtration circulation system through a negative pressure airflow; S4, curing the coating within a specified temperature range.

[0024] Specifically, by stretching the cleaned coil spring along its axial direction to the target pitch and then spraying it, the paint mist can more evenly cover the surface of the spring, including the area between adjacent spring coils, thereby improving the uniformity and integrity of the coating and enhancing the corrosion resistance and protective performance of the spring. The stretched spring is suspended on a carrier and synchronously performs rotation and axial translation in the paint spray booth. This composite motion mode enables all parts of the spring to be fully exposed to the charged paint mist, further ensuring the uniformity of the coating, improving the coating efficiency, reducing the number of uncoated areas, and improving product quality; using negative pressure airflow to guide the unabsorbed paint mist to the filtration circulation system can effectively reduce the diffusion and residue of the paint mist in the paint spray booth, improve the working environment, and reduce pollution; on the other hand, it realizes the recycling of the paint mist, saves resources, and reduces costs; implementing coating curing in a specified temperature range can ensure the curing effect of the coating, so that the coating has good adhesion, hardness, wear resistance and other properties, thereby extending the service life of the spring.

[0025] Furthermore, before step S1, step S01 is also included: the coil spring is sequentially passed through a degreasing station, a water washing station, a phosphating station and a pure water rinsing station; it can be understood that the previous cleaning process can thoroughly remove grease, impurities, etc. on the surface of the coil spring, improve the cleanliness and activity of the spring surface, provide a good base for subsequent spraying, enhance the bonding force between the paint mist and the spring surface, and further improve the quality and durability of the coating.

[0026] Specifically, a specialized degreaser is used to clean grease from the spring surface. A water wash station removes any remaining degreaser from the spring surface. A phosphating station phosphates the spring, forming a dense phosphate film on the surface and enhancing the adhesion between the coating and the spring substrate. A pure water rinse ensures that the phosphated spring surface is clean and free of impurities. This series of pretreatment steps, followed by the subsequent spraying operation, significantly improves the coating's quality and adhesion, extending the spring's service life.

[0027] Optionally, in some optional embodiments, the degreasing station, water washing station, phosphating station and pure water rinsing station can be equipped with parallel redundant pump groups. The redundant pump groups include a main working pump and a backup pump. The two pumps are connected in parallel through an electromagnetic valve and automatically switch in response to the pressure sensor signal. Through the dual-pump parallel structure, the pretreatment process is maintained in continuous operation when the main pump fails, thereby solving the problem of decreased coating adhesion caused by cleaning interruption.

[0028] Furthermore, the target pitch is 1.2-1.5 times the original pitch of the coil spring. It can be understood that setting an extreme target pitch ensures that there is sufficient spacing between adjacent spring coils after the spring is stretched, which is convenient for the full adhesion of paint mist, and does not over-stretch the spring to cause its performance to be damaged. It reasonably balances the spraying effect and the mechanical properties of the spring, so that the coating can better cover the spring surface and improve the corrosion protection and decorative effects.

[0029] Furthermore, it is stipulated that the gap between adjacent coils of the coil spring after stretching in step S1 is ≥3mm, which further ensures that the charged paint mist can smoothly enter between the adjacent coils and has sufficient space to form a uniform coating, thereby avoiding the situation where the coating is uneven or missing due to the paint mist having difficulty entering the coil gap being too small, thereby improving the product qualification rate and quality stability.

[0030] Furthermore, the use of charged spray application under a high-voltage electric field of -70kV to -90kV, with a charge-to-mass ratio of paint particles of 1.2-1.8mC / kg, can produce a strong electrostatic adsorption effect on the surface of the spring, so that the paint mist particles adhere more tightly to the spring surface, improving the utilization rate of the paint and the adhesion of the coating. At the same time, it can also better control the distribution of the paint mist and further optimize the uniformity and quality of the coating.

[0031] Furthermore, the temperature range for coating curing is set at 60-80°C. This temperature range can ensure that the chemical reaction in the coating proceeds fully, allowing the coating to cure quickly and achieve the required performance indicators such as hardness and wear resistance, while also preventing the coating from burning, discoloring, or performance degradation due to excessively high temperatures. This ensures the quality and stability of the coating and adapts to the curing requirements of different types of coatings and spring materials.

[0032] Please refer to Figure 2-Figure 3Some embodiments of the present invention also provide a coil spring spraying device 1, including a paint spraying chamber 10, the bottom of which is provided with a collecting panel 100 arranged at an angle; it is conducive to the centralized collection and guidance of non-absorbed paint mist, improves the recovery efficiency of paint mist, reduces the residual and secondary pollution of paint mist in the paint spraying chamber 1, and facilitates subsequent filtration and circulation treatment. A dynamic stretching module 11 is arranged in the paint spraying chamber 10, and includes a fixed disk 110 and a movable disk 111 with adjustable spacing; it can be flexibly adjusted according to coil springs of different specifications to achieve precise axial stretching, adapt to the production needs of various products, and improve the versatility and flexibility of the equipment. A composite motion mechanism 12 includes a driving device 120 for driving the fixed disk 110 to rotate and a lifting device 121 for driving the fixed disk 110 to move axially; it can realize the synchronous rotation and axial translation movement of the spring during the spraying process, ensure the uniformity of the coating, improve the coating quality and efficiency, and has a high degree of automation, reducing the intensity and error of manual operation. The electrostatic spray system 13, with a negative electrode generator 130 at the outlet of its spray gun 131, effectively charges the paint mist and creates a good electrostatic adsorption effect on the spring surface, improving paint utilization and coating adhesion, and optimizing the spraying effect. The closed-loop recovery system 14, connecting the collector panel 100 with the circulation pipeline 142 of the spray system, forms a closed-loop process for paint mist recovery, filtration, and reuse, saving resources, reducing production costs, and minimizing environmental pollution, meeting the requirements of environmentally friendly production.

[0033] Specifically, the inclination angle of the current collecting panel 100 is 30°; in actual use, the pre-treated coil spring is installed on the dynamic stretching module 11, and the distance between the fixed disk 110 and the movable disk 111 is adjusted by the hydraulic cylinder to stretch the spring to the target pitch. Then the composite motion mechanism 12 and the electrostatic spraying system 13 are started, and the spring is evenly sprayed with charged paint mist under the composite motion of rotation and axial translation. The unabsorbed paint mist is guided to the closed-loop recovery system 14 under the action of the negative pressure airflow, and after being processed by the cyclone separator 140 and the filter 141, it is sent back to the electrostatic spraying system 13 for recycling. After the spraying is completed, the spring is transferred to the curing equipment for coating curing treatment.

[0034] For details, please refer to Figure 2 and Figure 3 The collecting panel 100 is provided with air holes 1000. During the spraying process, the air holes continuously spray air, so that a layer of negative pressure air flow layer is formed on the surface of the collecting panel. The fallen paint will not come into contact with the collecting panel 100, and will not cause pollution to the collecting panel 100. At the same time, more paint can enter the closed-loop recovery system 14.

[0035] Furthermore, the linear actuator of the dynamic stretching module 11 is a hydraulic cylinder or a servo electric cylinder, which has the advantages of high motion accuracy, good stability, and strong load-bearing capacity. It can ensure that the spacing between the fixed disk 110 and the movable disk 111 is accurately adjusted, and can maintain a stable stretching force during the stretching process, thereby ensuring the consistency of the spring stretching quality. At the same time, the hydraulic cylinder and the servo electric cylinder have a fast response speed, are easy to realize automatic control, and improve production efficiency and equipment reliability.

[0036] Specifically, the displacement accuracy of the linear actuator is ±0.1mm, and the maximum stroke is ≥500mm.

[0037] Optionally, in order to accurately determine the spring stretching amount in the dynamic stretching module 11, machine identification or a magnetic scale may be used to accurately identify the spring stretching amount, thereby accurately avoiding damage to the coil spring due to excessive stretching.

[0038] Furthermore, the fixing plate 110 includes a hook 1100 design, which facilitates the quick and secure hanging of the coil spring on the carrier, is easy to operate, and improves production efficiency. Moreover, the hook 1100 has a simple structure, is easy to manufacture and maintain, and can adapt to the suspension requirements of coil springs of different sizes and shapes, and has strong versatility.

[0039] Furthermore, the closed-loop recovery system 14 includes a cyclone separator 140 and a filter 141. The cyclone separator 140 can use the principle of centrifugal force to separate large particles of impurities and part of the paint mist in advance, thereby reducing the burden on subsequent filters and improving filtration efficiency; the filter 141 is arranged in the circulation pipeline 142, which can further finely filter the paint mist, remove tiny particles and impurities therein, ensure that the quality of the recovered paint mist meets the requirements for re-spraying, ensure the quality stability of the coating, and at the same time extend the service life of the equipment and reduce operating costs.

[0040] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0041] Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of the present application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in reverse order depending on the functions involved. For example, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Furthermore, features described with reference to certain examples may be combined in other examples.

[0042] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. A method for spraying a coil spring, characterized in that: The following steps are involved: S1, stretching the cleaned coil spring along its axial direction to the target pitch; S2, suspending the stretched spring on a carrier, and performing simultaneous rotation and axial translation in the paint spraying chamber while applying charged paint mist to the spring surface; S3, directing the unabsorbed paint mist to the filtration circulation system through negative pressure airflow; S4, curing the coating in a specified temperature range.

2. The method for spraying a coil spring according to claim 1, wherein: Before step S1, the following steps are also included: S01, the coil spring passes through the degreasing station, water washing station, phosphating station and pure water rinsing station in sequence.

3. The method for spraying a coil spring according to claim 1, wherein: The target pitch is 1.2-1.5 times the original pitch of the coil spring.

4. The method for spraying a coil spring according to claim 3, wherein: After the stretching in step S1, the gap between adjacent coils of the coil spring is ≥3 mm.

5. The method for spraying a coil spring according to claim 1, wherein: The charged spray is applied in a manner such that the charge-to-mass ratio of the paint particles is 1.2-1.8 mC / kg under a high voltage electric field of -70 kV to -90 kV.

6. The method for spraying a coil spring according to claim 1, wherein: The temperature range during coating curing is 60-80°C.

7. A coil spring spraying device, characterized in that: include: The paint spraying chamber has a current collecting panel arranged at an angle at the bottom; A dynamic stretching module is provided in the paint spraying chamber and comprises a fixed plate and a movable plate with adjustable spacing; A composite motion mechanism, comprising a driving device for driving the fixed disk to rotate and a lifting device for driving the fixed disk to move axially; An electrostatic spraying system having a negative electrode generator at its outlet end; A closed-loop recovery system connects the current collecting panel with a circulation pipeline of the spraying system.

8. The coil spring spraying device according to claim 7, characterized in that: The linear actuator of the dynamic stretching module is a hydraulic cylinder or a servo electric cylinder.

9. The coil spring spraying device according to claim 7, characterized in that: The fixing plate includes a hook.

10. The spring spraying device according to claim 7, characterized in that: The closed-loop recovery system includes a cyclone separator and a filter. The inlet of the cyclone separator is communicated with the current collecting panel, and the filter is arranged in the circulation pipeline.

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