Noise reduction type armature and preparation method thereof

Abstract

The invention discloses a noise reduction type armature and a preparation method thereof, and belongs to the technical field of brakes, the noise reduction type armature specifically comprises an armature main body, the armature main body is coated with a wear-resistant noise reduction coating, the wear-resistant noise reduction coating is of a compact nanocrystalline / amorphous structure, the microhardness of the wear-resistant noise reduction coating is larger than 1500 HV, and the thickness of the wear-resistant noise reduction coating is larger than 10 mm. The wear-resistant noise reduction layer is deposited on the surface of the armature through PVD. According to the scheme, the surface of the armature is coated with the high-strength and compact nanocrystalline / amorphous composite structure, so that plastic deformation and microcrack propagation of a friction contact surface can be remarkably reduced, and vibration noise caused by collision of surface rough peaks is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of brakes, and particularly relates to a noise-reducing armature and a preparation method thereof. Background Art

[0002] The armature is the main working component for braking in a brake. For example, in an electromagnetic brake, it mainly includes a brake disc, an electromagnet, an armature, and a spring. During braking, through the action of the electromagnet, the braking force generated by the contact between the armature and the brake disc realizes the braking function.

[0003] Since the working principle of the brake is to achieve braking through the frictional force generated after the armature and the brake disc are pressed tightly, during the process of the armature and the brake disc being pressed tightly, there will be noise generated when the brake disc contacts and rotates on the surface of the armature before stopping, as well as noise generated when the armature collides with the brake disc. Currently, the main solutions for suppressing noise during the brake process on the market are as follows: For example, the utility model patent with the publication number CN208565320U discloses a snap-in type noise-reducing electromagnetic braking device, which has a noise-reducing function during braking. However, its main working principle is to form a cavity structure through the T-shaped groove and L-shaped groove provided on the partition layer of the top cover to reduce air vibration and a buffer layer provided on the base to achieve the overall noise reduction effect;

[0004] Or, for example, the shock-absorbing and noise-reducing armature disclosed in the invention patent with the publication number CN105097181A. By setting a spring assembly, during the working process of the armature, when the armature impacts, the acting force acts on the top head instead of directly acting on the magnetic material iron core, and the vibration energy is absorbed through the compression deformation of the spring and the noise generated by the collision of two rigid components is reduced.

[0005] One of the above two is to reduce the noise generated by the overall vibration of the device after the armature and the brake disc are in contact, and the other is to reduce the noise generated by the vibration during the collision between the armature and the brake disc through a buffer structure. Both can reduce noise to a certain extent. However, the above technologies do not consider how to handle the noise generated by the friction between the contact surfaces of the armature and the brake disc during the process of the armature and the brake disc being in contact. Based on this problem direction, the present application has developed a noise-reducing armature that can effectively reduce the noise generated by the friction between the armature and the brake disc during the contact process. Summary of the Invention

[0006] The purpose of the present invention is to provide a noise-reducing armature and a preparation method thereof to solve the problems raised in the above background art.

[0007] To achieve the above object, a technical solution adopted by the present invention is: a noise-reducing armature, including a prior armature body, wherein a wear-resistant and noise-reducing coating is coated on the armature body, the wear-resistant and noise-reducing coating is a dense nanocrystalline / amorphous structure, and the microhardness of the wear-resistant and noise-reducing layer is greater than 1500 HV.

[0008] Preferably, the friction coefficient range value of the coating surface is 0.25 to 0.6.

[0009] Preferably, the surface roughness Ra of the wear-resistant and noise-reducing coating is ≤ 1.6 μm.

[0010] Preferably, the material of the wear-resistant and noise-reducing coating includes any one of CrAlN, CrN or CrAlNSi.

[0011] Preferably, the thickness of the wear-resistant and noise-reducing coating is between 1 - 10 μm.

[0012] Among them, the present invention also discloses a preparation method of a noise-reducing armature for preparing the above-mentioned noise-reducing armature, which specifically includes the following steps:

[0013] S1: The armature needs to be subjected to at least one tempering treatment at a temperature above 300 °C;

[0014] S2: Control the surface roughness of the armature to be between Ra0.1 and Ra1.6 through a grinding device;

[0015] S3: Clean the surface of the armature with a cleaner to ensure that its surface has no oil stains and no dust;

[0016] S4: Deposit the coating material on the surface of the armature through PVD technology.

[0017] The beneficial effects of the present invention: By coating a high-strength and dense nanocrystalline / amorphous composite structure on the surface of the armature, the plastic deformation and microcrack propagation of the friction contact surface can be significantly reduced, thereby reducing the vibration noise caused by the collision of surface rough peaks;

[0018] Among them, the oxide layer formed after the coating is oxidized, which has both self-lubricating and wear-resistant properties, can effectively reduce the adhesive friction between metals and the resulting vibration abnormal noise;

[0019] Among them, the coatings of CrAlN, CrN or CrAlNSi materials can meet the characteristics of high strength and dense nanocrystalline / amorphous composite structure, the friction coefficient range is between 0.25 and 0.6, and the surface roughness Ra ≤ 1.6 μm, effectively meeting the usage requirements of this application; among them, the introduction of aluminum element in CrAlN and CrAlNSi, and the doping of silicon element in CrAlNSi have both improved the damping performance of the coating, absorbed vibration energy through grain boundaries and phase boundaries, and suppressed the propagation of high-frequency noise. For example, the silicon element of CrAlNSi can refine the grain boundaries and enhance the interface energy dissipation ability. Description of the Drawings

[0020] Figure 1 It is a detection result diagram of the noise intensity of the armature during braking friction in the comparative example;

[0021] Figure 2 It is a detection result diagram of the noise intensity of the armature during braking after coating with CrAlN coating; Detailed Embodiments

[0022] The following describes in detail the preferred embodiments of the present invention with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0023] Embodiment:

[0024] A noise-reducing armature and its preparation method, including an armature body, on which a wear-resistant and noise-reducing coating is coated. The wear-resistant and noise-reducing coating is a dense nanocrystalline / amorphous structure, and the microhardness of the wear-resistant and noise-reducing layer is greater than 1500 HV.

[0025] Among them, the friction coefficient range of the coating surface is 0.25 - 0.6.

[0026] Among them, the surface roughness Ra of the wear-resistant and noise-reducing coating is ≤ 1.6 μm.

[0027] Among them, the material of the wear-resistant and noise-reducing coating includes any one of CrAlN, CrN or CrAlNSi.

[0028] Among them, the thickness of the wear-resistant and noise-reducing coating is between 1 - 10 μm.

[0029] Among them, this solution also provides a preparation method for a noise-reducing armature, which is used to prepare the above-mentioned noise-reducing armature, and specifically includes the following steps:

[0030] S1: The armature needs to be tempered at least once at a temperature above 300 °C; this temperature tempering treatment is because when depositing the coating material by PVD later, it can avoid the problem of softening and deformation of the armature at high temperature caused by too high temperature of the coating material.

[0031] S2: Control the surface roughness of the armature to be between Ra0.1 and Ra1.6 through a polishing device. The surface roughness in this range can effectively ensure the connection strength between the coating material and the armature surface after the coating material is deposited on the armature surface;

[0032] S3: Clean the armature surface with a cleaner to ensure that its surface is free of oil stains and dust;

[0033] S4: Deposit the coating material on the armature surface through PVD technology.

[0034] Comparative example:

[0035] There is no case of using a coating on the armature in the existing market brakes. To ensure the corrosion resistance and wear resistance of the armature, it is directly used after processing the armature through basic surface treatment processes such as QPQ (quenching - polishing - quenching), gas nitriding, sandblasting, polishing, galvanizing, and Dacromet. In this embodiment, an electromechanical brake is selected for data detection. In this brake, it is required that the torque between the armature and the brake disc during braking is greater than 0.85 N·m and less than 2.1 N·m, and the service life of the armature is greater than 20,000 rpm. To avoid the occasionality of experimental data, multiple samples are selected from the same type of brake in this scheme for testing and the following data are obtained (see Table 1):

[0036] Table 1:

[0037] Sample 1 Sample 2 Initial Torque (Nm) 1.78 1.96 Final Torque (Nm) 1.78 1.82 Running-in Life (rpm) Approximately 50,000 Approximately 30,000 Expected Life (rpm) 20000 20000 Main Noise Type High-frequency Squealing Noise High-frequency Squealing Noise Noise Duration Phase Brake Friction Phase Brake Friction Phase

[0038] In this application, the initial torque refers to the pre - run - in torque, that is, the torque reached when the armature and the brake disc adapt in the first few laps during the run - in experiment. The final torque refers to the torque at the end of the life test. The run - in life refers to the number of run - in laps when obvious noise appears during the braking friction experiment between the armature and the brake disc. The expected life refers to the minimum life to meet the product use requirements. The main noise types are general classifications divided according to frequency. The noise duration stages include the initial braking stage and the braking friction stage. This scheme is developed based on the noise of the friction between the armature and the brake disc. Therefore, only the noise in the braking friction stage needs to be considered in this scheme. From the data in the above table, it can be seen that during the braking process of the uncoated armature in hard contact with the brake disc, when it rubs against the brake disc, mainly high - frequency screeching noises are generated, which are mainly caused by factors such as the friction coefficient between the armature and the brake disc and the particle protrusions on the metal surfaces of the armature and the brake disc.

[0039] Experimental example 1:

[0040] The CrAlN material was deposited onto the armature through the preparation method of the noise-reducing armature in the embodiments, and multiple tests were conducted by controlling variables to obtain the following test data (see Table 2):

[0041] Table 2:

[0042]

[0043]

[0044] By observing Figure 1 , Figure 2 and the changes in the main noise types in Table 2, it can be seen that the main noise type has changed from high-frequency screeching noise (noise intensity higher than the slight range) to subtle instrument current noise (noise intensity within the slight to no-noise range). From this, it can be seen that the coating of the CrAlN material can effectively reduce the noise frequency and achieve noise attenuation. Therefore, based on the feasibility of noise reduction using this material, this solution further conducts experiments on the relationship between the coating thickness and the service life of the armature and obtains the data in Table 2. From the detection data in Table 2, it can be seen that the coating thickness has a greater impact on the running-in life of the armature. Specifically, in the actual experimental data, when the coating thickness exceeds 10 μm (12 μm), the service life of the armature no longer meets the expected life standard of the armature (whereas when the coating thickness is less than 1 μm, the expected life is also not reached, and this data table is not shown). Analyzing the reasons, it is mainly due to the influence of the connection strength between the coating and the surface of the armature, which is a difficult problem that cannot be well overcome at present. Therefore, the optimal value of the coating thickness on the armature is between 1 - 10 μm, and within this range, the running-in life of the armature can be effectively guaranteed to meet the product production requirements.

[0045] To further determine the appropriate range of other noise parameter-influencing factors, the applicant further conducts a comparative analysis of the friction coefficient of the coating and obtains the following detection data (see Table 3):

[0046] Table 3:

[0047]

[0048]

[0049] By observing the data in Table 3, it can be seen that when the friction coefficient is small, the running-in life slightly increases, and when the friction coefficient is large, the running-in life slightly decreases. However, considering the data in Table 2 comprehensively, the friction coefficient has little effect on the running-in life of the armature. It mainly affects the initial torque and final torque of the brake. When the friction coefficient is low, the torque does not meet the standard, affecting the braking effect. When the friction coefficient is relatively large, the torque becomes larger, and it is impossible to ensure whether the torque can meet the customer's requirements during this period.

[0050] Experimental Example 2:

[0051] By depositing CrN material on the armature through the preparation method of the noise-reducing armature in the embodiment and conducting multiple tests by controlling variables, the following test data are obtained (see Table 4):

[0052] Table 4:

[0053] Sample 1 Sample 2 Sample 3 Initial Torque (Nm) 0.98 1.55 1.56 Final Torque (Nm) 1.38 1.66 1.76 Coating Thickness (μm) - Running-in Life (rpm) 4 - Approximately 80,000 4 - Approximately 74,000 4 - Approximately 74,000 Coating Thickness (μm) - Running-in Life (rpm) 8 - Approximately 75,000 8 - Approximately 72,000 8 - Approximately 72,000 Coating Thickness (μm) - Running-in Life (rpm) 12 - Approximately 32,000 12 - Approximately 21,000 12 - Approximately 19,000 Expected Life (rpm) 20000 20000 20000 Noise Frequency (HZ) Subtle Instrument Current Noise Subtle Instrument Current Noise Subtle Instrument Current Noise Noise Duration Phase Brake Friction Phase Brake Friction Phase Brake Friction Phase

[0054] By observing the changes in the main noise types in Table 4, it can be seen that the CrN material layer can effectively reduce the noise frequency and weaken the noise. Therefore, based on the feasibility of noise reduction with this material, this solution further experiments on the relationship between the coating thickness and the service life of the armature and obtains the data in Table 4. From the detection data in Table 4, it can be seen that the coating thickness has a greater impact on the running-in life of the armature. Specifically, the greater the coating thickness, the smaller the running-in life of the armature. When the coating thickness exceeds 10 μm, the service life of the armature no longer meets the minimum service life standard of the armature. In this interval, the running-in life of the armature can be effectively guaranteed to meet the product production requirements. It can be seen that the characteristics of the material in this experimental example are relatively similar to those in Experimental Example 1.

[0055] To further determine the impact of other parameters of this material on noise and life, the applicant also conducts a further comparative analysis of the friction coefficient of the coating and obtains the following detection data (see Table 5):

[0056] Table 5:

[0057] Sample 1 (Friction Coefficient 0.1) Sample 2 (Friction Coefficient 0.3) Sample 3 (Friction Coefficient 0.7) Initial Torque (Nm) 0.72 1.55 1.96 Final Torque (Nm) 0.81 1.63 2.33 Coating Thickness (μm) 4 4 4 Running-in Life (rpm) Approximately 82,000 Approximately 73,000 Approximately 72,000 Expected Life (rpm) 20000 20000 20000 Main Noise Type Subtle Instrument Current Noise Subtle Instrument Current Noise Subtle Instrument Current Noise Noise Duration Phase Brake Friction Phase Brake Friction Phase Brake Friction Phase

[0058] By observing the data in Table 5, it can be seen that the friction coefficient has little effect on the running-in life of the armature, and the influence trend is relatively similar to that in Experimental Example 1, so no specific description will be given here.

[0059] Experimental Example 3:

[0060] By depositing CrAlNSi material on the armature through the preparation method of the noise-reducing armature in the embodiment and conducting multiple tests by controlling variables, the following test data are obtained (see Table 6):

[0061] Table 6:

[0062]

[0063]

[0064] By observing the changes in the main noise types in Table 6, it can be seen that the coating of the CrAlNSi material can effectively reduce the noise frequency and weaken the noise. The characteristics of the material in this experimental example are similar to those of the material in Experimental Example 1. Its effects on noise and the service life of the armature are similar to those of the materials in Experimental Example 1 and Experimental Example 2. Therefore, this material can meet the practical requirements of this application, can reduce noise, and effectively ensure the service life of the armature.

[0065] Similarly, to further determine the effects of other parameters of this material on noise and life, the applicant also conducted a further comparative analysis of the friction coefficient of the coating and obtained the following test data (see Table 7):

[0066] Table 7:

[0067] Sample 1 (Friction Coefficient 0.1) Sample 2 (Friction Coefficient 0.3) Sample 3 (Friction Coefficient 0.7) Initial Torque (Nm) 1.63 1.42 1.87 Final Torque (Nm) 1.75 1.63 2.05 Coating Thickness (μm) 6 6 6 Running-in Life (rpm) Approximately 57,000 Approximately 54,000 Approximately 52,000 Expected Life (rpm) 20000 20000 20000 Main Noise Type Subtle Instrument Current Noise Subtle Instrument Current Noise Subtle Instrument Current Noise Noise Duration Phase Brake Friction Phase Brake Friction Phase Brake Friction Phase

[0068] By observing the data in Table 7, it can be seen that the friction coefficient has little effect on the running-in life of the armature, and the influence trend is similar to that in Experimental Example 1 and Experimental Example 2. Therefore, no specific description will be made.

[0069] Summary description:

[0070] Refer to Figure 1 、 Figure 2 , in this solution, the equipment running-in test signals and periodic noise analysis were carried out on Comparative Example 1 and Experimental Example 1 (the results of Experimental Example 2 and Experimental Example 3 are for reference Figure 2 ). From the experimental results, it can be seen that through the design solution of this application, during the friction braking process between the armature and the brake disc, the harsh metallic friction sound (high-frequency screeching noise) that can be heard by the human ear hardly exists, and more are the slight instrument current sounds and slight vibrations generated during the slight metal movement process, which are hardly audible to the human ear. Thus, it can be seen that this solution can effectively reduce the noise during the braking process between the armature and the brake disc.

[0071] In summary, based on the problem of high-frequency noise generated by the hard contact friction between the armature and the brake disc during braking, this solution analyzes from the generation principle of high-frequency noise. Considering that materials with a high-strength and dense nanocrystalline / amorphous composite structure may solve the above problems, corresponding experiments are conducted for detection and analysis to find suitable materials. Moreover, through experimental analysis of the parameter characteristics of the corresponding materials, the effects of different values of the same parameter on the noise between the armature and the brake disc and the service life of the armature are found. Finally, a coating that meets the requirements of the armature service life and can effectively reduce the high-frequency noise generated during braking between the armature and the brake disc is obtained, realizing the research and development of the noise-reducing armature in this application.

[0072] The above are only the embodiments of the present invention, and thus do not limit the patent scope of the present invention. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A noise-reducing armature, characterized in that: It includes an armature body, and a wear-resistant and noise-reducing coating is applied on the armature body. The wear-resistant and noise-reducing coating has a dense nanocrystalline / amorphous structure, and the microhardness of the wear-resistant and noise-reducing layer is greater than 1500 HV.

2. The noise reduction type armature according to claim 1, characterized in that: The friction coefficient range on the surface of the coating is 0.25 - 0.

6.

3. The noise reduction type armature according to claim 1, characterized in that: The surface roughness Ra of the wear-resistant and noise-reducing coating is ≤ 1.6 μm.

4. A noise reduction armature according to any one of claims 1-3, characterized in that: The material of the wear-resistant and noise-reducing coating includes any one of CrAlN, CrN or CrAlNSi.

5. The noise-reducing armature according to claim 4, wherein: The thickness of the wear-resistant and noise-reducing coating is between 1 - 10 μm.

6. A preparation method of a noise-reducing armature for preparing the noise-reducing armature according to any one of claims 1-5 above, characterized in that: It includes the following steps: S1: The armature needs to be subjected to at least one tempering treatment at a temperature above 300 °C. S2: Control the surface roughness of the armature to be between Ra0.1 and Ra1.6 through a grinding device. S3: Clean the surface of the armature with a cleaner to ensure that its surface has no oil stains and no dust. S4: Deposit the coating material on the surface of the armature through PVD technology.

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