A Microscopic Elastic Energy Absorbing Layer Surface Microtexture and Its Processing Method

Abstract

The present invention discloses a surface micro-texture of a micro elastic energy absorption layer, which relates to the field of mechanical engineering. The surface micro-texture is formed on the surface of a material, and the surface of the material is the friction surface of a part. A single texture in the surface micro-texture includes a convex part and a contact part surrounding the convex part. The contact part is fixedly in contact with the surface of the material, and a micro chamber is formed between the convex part and the surface of the material, and the periphery of the micro chamber is sealed by the contact part. A high-strength and high-wear-resistant thin layer composed of surface micro-textures is formed on the original friction surface, which greatly improves the friction conditions. The micro chamber stores gas. Due to the compressibility of the gas, on the one hand, it can provide a deformation space for the micro arc segment, and on the other hand, the internal gas can also provide buffering. A micro groove is formed between two adjacent convex parts, which can provide a storage space for lubricant. When the thin layer on the metal surface is pressed, the arc segment of the convex part tends to be flat, making it easier for the lubricant to flow out, and can better reduce friction and impact loss.

Description

Technical Field

[0001] The present invention relates to the field of mechanical engineering, and specifically relates to a surface micro-texture of a micro elastic energy-absorbing layer and a processing method thereof. Background Technique

[0002] The motion system is always accompanied by friction and wear, and more than 50% of equipment damage or failures are due to wear. Lubrication and surface strengthening technologies are common methods to reduce friction and wear. Common cases include: coated composite lubricating oil, nitrided / carbonized layer composite lubricating phase, etc. However, in actual applications, such methods require sufficient lubricant, and the bonding strength between the lubricating phase and the coating surface directly determines the service time of the solid lubricating film on the coating surface, but there are problems of lubricant leakage and failure, resulting in increased mechanical wear.

[0003] The surface micro-texture technology is different from surface strengthening. The surface micro-texture technology processes a lattice of pits or micro-grooves with a certain size arrangement on the friction surface by using subtractive manufacturing processes such as mechanical external force or laser etching on the friction surface, which can effectively improve the surface tribological properties. However, processing the friction surface by this method is essentially a damage to the friction surface, which will affect the integrity of the friction surface and easily lead to premature damage of the parts. Summary of the Invention

[0004] Object of the Invention: Aiming at the above disadvantages, the present invention provides a surface micro-texture of a micro elastic energy-absorbing layer that reduces friction and wear.

[0005] The present invention also provides a processing method for the surface micro-texture of the above micro elastic energy-absorbing layer.

[0006] Technical Solution: To solve the above problems, the present invention adopts a surface micro-texture of a micro elastic energy-absorbing layer. The surface micro-texture is formed on the surface of a metal shaft material, and the material surface is the friction surface of the part. Each individual texture in the surface micro-texture includes a convex part and a contact part surrounding the convex part. The contact part is fixedly in contact with the material surface, and a micro cavity is formed between the convex part and the material surface, and the micro cavity is sealed by the contact part around it.

[0007] Furthermore, the surface micro-texture is made of metal materials, including alloy structural steel, molybdenum alloy, chromium copper alloy, and superalloy. The material thickness range of the surface micro-texture is 0.01 mm to 0.05 mm. The metal surface thin layer forming the surface micro-texture has high strength, high wear resistance, electrical conductivity, and weldability.

[0008] Furthermore, the width of the contact part joined by resistance welding has a linear correlation with the material thickness and the calculation formula for the width range of the contact part between two adjacent convex parts is:

[0009] ;

[0010] ;

[0011] in, is the minimum width of the contact portion between two adjacent protrusions, is the maximum width of the contact portion between two adjacent protrusions, is the material thickness of the surface microtexture.

[0012] Furthermore, the chord length corresponding to the protrusion for: , Δ is the height of the protrusion, the height of the protrusion , The size of a single texture is ,size .

[0013] Furthermore, the material surface is a metal material with high strength, high hardness, electrical conductivity and weldability, including alloy structural steel, chromium-copper alloy and high-temperature alloy. The texture array grid in the surface micro-texture is arranged on the material surface. The contact portion and the material surface are welded by a large current. The metal surface thin layer and the part friction surface are welded by a large current to form a contact portion. The raised portion of the raised micro-arc segment is formed by warping when the metal surface thin layer is welded to the part contact surface. The micro-chamber is a chamber surrounded by the raised micro-arc segment, the metal surface thin layer and the part friction surface.

[0014] At the welded joint between the thin metal surface layer and the contact surface of the part, warping occurs around to form raised micro arc segments, and micro grooves are formed on the surface. The micro grooves are composed of the protrusions of the contact part and the two adjacent micro arc segments, which can provide storage space for the lubricant. The width of the micro grooves is equal to the width of the contact segment. After actual application, when the thin metal surface layer is under pressure, the arc segment tends to be flat, making it easy for the lubricant to flow out, which can better reduce friction and impact loss. The micro grooves can also provide storage space for hard abrasive particles such as grinding chips. After actual application, the debris generated on the friction surface and the hard tiny particles mixed in the air will gather in the grooves without interacting with the friction surface, which can greatly avoid abrasive wear.

[0015] The present invention also provides a method for processing the surface micro-texture of the micro-elastic energy-absorbing layer, comprising the following steps:

[0016] (1) A metal thin layer with a surface micro-texture is placed on the surface of the material, and a processing roller is applied to pressurize the metal thin layer. The metal thin layer at the pressurized position contacts the material surface, and the metal thin layer warps on both sides of the pressurized position to form a gap between the metal thin layer and the material surface;

[0017] (2) Apply electricity to form an electric current loop among the processing roller, the metal thin layer, and the material surface. The contact part between the metal thin layer and the material surface is heated and welded, and welding is performed at the edge of the material surface (such as the shaft end) to form a seal between the part and the metal thin layer, trapping the internal air.

[0018] (3) After the processing roller moves along the processing trajectory in the first direction, move a preset distance, and then perform a processing trajectory movement parallel to the first direction. Repeat this step until all the processing trajectories in the first direction of the metal thin layer are completed.

[0019] (4) Control the rotation direction of the processing roller. After the processing roller moves along the processing trajectory in the second direction, move a preset distance, and then perform a processing trajectory movement parallel to the second direction. Repeat this step until all the processing trajectories in the second direction of the metal thin layer are completed; there is an included angle between the first direction and the second direction.

[0020] Further, the first direction is perpendicular to the second direction. The material surface is the surface of a cylindrical part, and the metal thin layer is sleeved outside the cylindrical part, keeping coaxial with the cylindrical part and restricting the axial displacement of the metal thin layer. The contact area between the processing roller and the metal thin layer is small. When forming a loop, most of the current will flow from the contact point to the part, generating a large amount of Joule heat at the contact point to complete the welding. Based on the processing trajectory, the process of continuous repetition of pressing, warping, heating, and welding is carried out to form an array grid micro-elastic energy-absorbing layer surface micro-texture on the part surface.

[0021] Beneficial effects: Compared with the prior art, the significant advantage of the present invention is to form a high-strength and high-wear-resistant thin layer composed of surface micro-textures on the original friction surface, greatly improving the friction conditions. The micro-chamber stores gas. Due to the compressibility of the gas, on the one hand, it can provide a deformation space for the micro-arc section, and on the other hand, the internal gas can also provide buffering. Micro-grooves are formed between adjacent two convex parts, which can provide a storage space for lubricants. When the metal surface thin layer is pressed, the arc section of the convex part tends to be flat, making it easier for the lubricant to flow out, which can better reduce friction and impact loss. Using a high-strength and high-wear-resistant thin layer material to replace the original friction surface and form a surface micro-texture improves the surface wear resistance and impact resistance, reduces wear and impact damage, and at the same time reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is an axonometric sectional view of a single texture in the present invention.

[0023] Figure 2 It is a sectional view of a single texture in the present invention.

[0024] Figure 3 It is a schematic diagram of the shape of the surface micro-texture before and after being pressed in the present invention.

[0025] Figure 4 This is the overall schematic diagram when the micro-texture in the present invention is located on the outer surface of the part.

[0026] Figure 5 This is the cross-sectional view when the micro-texture in the present invention is located on the outer surface of the part.

[0027] Figure 6 This is the partial enlarged view of the micro-texture on the outer surface of the part in the present invention.

[0028] Figure 7 This is the overall schematic diagram when the micro-texture in the present invention is located on the inner surface of the part.

[0029] Figure 8 This is the cross-sectional view when the micro-texture in the present invention is located on the inner surface of the part.

[0030] Figure 9 This is the partial enlarged view of the micro-texture on the inner surface of the part in the present invention.

[0031] Figure 10 This is the schematic diagram of the principle of the processing device for the processing method in the present invention.

[0032] Figure 11 This is the schematic diagram of the axial processing process in the present invention.

[0033] Figure 12 This is the schematic diagram of the circumferential processing process in the present invention.

[0034] 101 - Single texture; 102 - Protrusion; 103 - Micro-chamber; 104 - Contact part; 105 - Micro-groove; 201 - Shaft-like part; 401 - Pipe wall-like part; 501 - Processing roller. Specific embodiments

[0035] Example 1

[0036] Such as Figure 1 And Figure 2As shown, a micro-elastic energy-absorbing layer surface micro-texture in this embodiment is formed on the surface of the material, and the surface of the material is the friction surface of the part. A single texture 101 in the surface micro-texture includes a protrusion 102 and a contact portion 104 surrounding the protrusion. The contact portion 104 is fixedly contacted and connected with the material surface. A micro-chamber 103 is formed between the protrusion 102 and the material surface, and the micro-chamber 103 is sealed around the contact portion 104. The two protrusions 102 and the middle contact portion 104 form a micro-groove 105. When the surface micro-texture is subjected to an external clamping force F and moves relative to the part, the protrusion 102 can undergo different degrees of elastic deformation according to the pressure and increase the heat dissipation area at the same time. The micro-chamber 103 can provide space for arc segment deformation, and the micro-groove 105 can provide storage space for lubricants and abrasive particles. Under the joint action of the three, the friction conditions between parts can be effectively improved, the friction performance can be improved, and the wear can be reduced.

[0037] like Figure 3 As shown, when a single texture 101 is compressed, the protrusion 102 will produce elastic deformation in the direction of the micro chamber 103, and will change to different degrees according to the magnitude of the force. Since the micro chamber 103 stores air, it can provide a buffer when it is impacted. At the same time, the height of the protrusion 102 is reduced, which can make the lubricant in the micro groove 105 flow out, and play a better role in lubrication, pressure resistance and heat dissipation. The contact width between the two protrusions of the resistance welding is =1.75mm~5mm, chord length of raised part =0.088176mm~0.900354mm, Δ=0.0528~0.3783mm, the size of a single texture =1.838176mm~5.900354mm.

[0038] like Figures 4 to 6 As shown, the surface micro-texture of the array grid elastic energy absorbing layer formed on the outer surface of the part is composed of a certain number of micro-texture units arranged in an array, and the outwardly raised micro-texture unit protrusions 102 replace the part surface for friction.

[0039] like Figures 5 to 9 As shown, the micro-texture on the surface of the array grid elastic energy absorbing layer formed on the inner surface of the part is replaced by the inwardly raised protrusions 102 of the micro-texture unit to generate friction on the surface of the part.

[0040] When the single texture and the part are combined together through the contact part 104, a large amount of Joule heat is generated by providing a large current to rapidly raise the contact part 104 to the required welding temperature, and at the same time, the processing roller 501 provides appropriate pressure to complete the contact part welding. When pressure is applied to the surface metal thin layer, the surface metal thin layer around the contact part 104 will be slightly warped to form a convex portion.

[0041] Example 2

[0042] As Figure 10 shown, in this example, 38CrMoAl alloy structural steel with a thickness of 0.4 mm is taken as an example, and detailed implementation methods and specific operation processes are given. The materials, numerical values, and relative positions used in this example are only exemplary and not restrictive.

[0043] Place the shaft parts 201 and the metal foil on the machine tool and clamp them to keep them coaxial. Use the processing roller 501 to weld the metal foil to the shaft parts by seam welding. During the forming process, locally heat the contact part 104 with a large current. As Figure 11 、 12 shown, the processing tool can adopt the processing roller 501 with a maximum diameter of 100 mm. The shaft parts 201 (or the pipe wall parts 401) are made of 41CrAlMo7 alloy structural steel with a diameter of 180 mm. According to ISO286-1, the fit clearance between the shaft and the hole can be obtained , take , and Δ = 0.2575 mm can be obtained. Take , and can be obtained; after calculation, can be obtained, and 3 mm can be taken. The dimension . The processing roller makes the metal thin layer fit with the parts by applying pressure to form the contact part, and the metal thin layer around the contact part produces a slight warping to form a micro warping arc segment.

[0044] During processing, the Joule heat effect of the current causes the metals on both sides of the contact part 104 to heat up rapidly. The time t can be calculated using Ohm's law and Joule's law:

[0045] ;

[0046] ;

[0047] where: Q is the required heat; I is the current; R is the resistance.

[0048] ;

[0049] ;

[0050] where: m is the mass; ρ is the density; V is the volume; c is the specific heat capacity; ΔT is the temperature change.

[0051] When welding 41CrAlMo7 and 38CrMoAl, the recommended welding temperature should be controlled within a range that can ensure full fusion of both materials while not exceeding their heat treatment temperatures. Specifically, the welding temperature should be close to the quenching temperature of 38CrMoAl, which is 940 °C. However, considering the actual conditions during the welding process and the influence of the heat-affected zone, the actual welding temperature may be slightly lower than this temperature, but usually not lower than the tempering temperature of 38CrMoAl, which is 640 °C, to ensure the performance and quality of the welded joint. Therefore, the set welding temperature needs to reach 900 °C. Assuming the room temperature is 20 °C, thus, ΔT = 880 °C. The volume of the contact section of the welded joint is approximately 3.6 mm³. The physical properties of 38CrMoAl are as follows: resistivity: 0.24 (Ω·mm²) / m, specific heat capacity: 343 J / (kg·°C), density: 7830 kg / m³. The required heat can be calculated as Q = 7830×3.6×10 -9 ×343×880 J = 8.50844192 J. The resistance is calculated as R = 0.24×1×10 -3 ÷(3.6×10 -6 ) Ω ≈ 66.67 Ω.

[0052] The current amplitude for the welding process is set as I = 10 A. Therefore, the required time can be calculated using Ohm's law as t = 8.50844192÷(10²×66.67) s = 0.001276 s = 1.276 ms.

[0053] The diameter of the processing roller 501 is 100 mm. Considering the influence of other factors such as heat dissipation on the temperature, the linear velocity of the contact point during processing is v1 = 0.25 m / s. The angular velocity of the processing roller can be set as ω1 = 5 rad / s.

[0054] As Figure 11 shown, after the processing roller 501 completes one seam welding process, control the processing roller 501 to move 3.54075 mm circumferentially, and repeat the above processing process until the axial processing is completed. As Figure 12 shown, after the axial processing is completed, control the processing roller 501 to rotate 90 degrees for circumferential processing. After the processing roller 501 completes one circumferential processing, control the processing roller 501 to move axially until the circumferential processing is completed.

Claims

1. A processing method for surface micro-texture of a micro elastic energy absorption layer, characterized in that, The surface micro-texture is formed on the surface of a metallic shaft material, and the material surface is the friction surface of the part. Each individual texture in the surface micro-texture includes a protrusion and a contact part surrounding the protrusion. The contact part is fixedly contact-connected to the material surface. A micro-chamber is formed between the protrusion and the material surface, and the periphery of the micro-chamber is sealed by the contact part. The texture array in the surface micro-texture is arranged in a grid pattern on the material surface; The processing method includes the following steps: (1) Place the metallic thin layer for forming the surface micro-texture on the material surface, and press the processing roller onto the metallic thin layer. The metallic thin layer at the pressing position contacts the material surface, and warping occurs on both sides of the pressing position of the metallic thin layer, forming a gap with the material surface; (2) Apply electricity, and a current loop is formed by the processing roller, the metallic thin layer, and the material surface. The contacting part between the metallic thin layer and the material surface is heated and welded, and welding is performed at the edge of the material surface to form a seal between the part and the metallic thin layer, trapping the internal air; (3) After the processing roller moves along the processing track in the first direction, move a preset distance, and then perform a processing track movement parallel to the first direction. Repeat this step until all the processing tracks in the first direction of the metallic thin layer are completed; (4) Control the rotation direction of the processing roller. After the processing roller moves along the processing track in the second direction, move a preset distance, and then perform a processing track movement parallel to the second direction. Repeat this step until all the processing tracks in the second direction of the metallic thin layer are completed; The first direction and the second direction form an angle.

2. The processing method of the surface micro-texture of the micro elastic energy absorption layer according to claim 1, characterized in that The surface micro-texture uses metallic materials, including alloy structural steel, molybdenum alloy, chromium copper alloy, and superalloy. The material thickness range of the surface micro-texture is 0.1 mm to 0.5 mm.

3. The processing method of the surface micro-texture of the micro elastic energy absorption layer according to claim 2, characterized in that, The width range calculation formula for the contact part between two adjacent protrusions is: ； ； Wherein, is the minimum width of the contact part between two adjacent convex parts, is the maximum width of the contact part between two adjacent convex parts, is the material thickness of the surface micro-texture.

4. The processing method of the surface micro-texture of the micro elastic energy absorption layer according to claim 3, characterized in that, The chord length corresponding to the convex part is: =(1.67~2.38) ×Δ, where Δ is the convex height of the convex part, and the convex height of the convex part , where is the fit clearance threshold between the shaft and the hole.

5. The processing method of the surface micro-texture of the micro elastic energy-absorbing layer according to claim 1 or 2, characterized in that, The material surface uses metallic materials, including alloy structural steel, chromium copper alloy, and superalloy.

6. The processing method of the surface micro-texture of the micro elastic energy-absorbing layer according to claim 1, characterized in that The contact part and the material surface are welded together by high current.

7. The processing method of the surface micro-texture of the micro elastic energy absorption layer according to claim 1, wherein, The first direction is perpendicular to the second direction.

8. The processing method of the surface micro-texture of the micro elastic energy-absorbing layer according to claim 1, characterized in that The material surface is the surface of a cylindrical part. The metallic thin layer is sleeved outside the cylindrical part or inside the wall of the cylindrical part, maintaining coaxiality with the cylindrical part and restricting the axial displacement of the metallic thin layer.

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