Diamond particle coating liquid, preparation method thereof and connecting assembly

Abstract

The invention discloses diamond particle coating liquid, a preparation method thereof and a connecting assembly, and relates to the technical field of vehicles. The diamond particle coating liquid comprises the following raw materials: diamond particles, a dispersing agent, a film-forming agent, a corrosion inhibitor, a coupling agent and a solvent. Wherein the coupling agent comprises at least one of a titanate coupling agent, an aluminate coupling agent and a silane coupling agent. The coupling agent is added into the diamond particle coating liquid, so that the diamond particles have strong coupling performance and can be tightly connected with a connecting surface piece when being coated on the connecting surface, a high-viscosity adhesive does not need to be adopted, a relatively thick coating does not need to be formed, the diamond particles do not need to be coated in the coating, and the service life of the diamond particles is prolonged. Therefore, the fully exposed diamond particles can be embedded into the connected pieces, sliding abrasion between the connecting pieces and the connected pieces is reduced, and the problems of bolt loosening, breaking and the like are reduced.

Description

Technical Field

[0001] The present application relates to the field of automobile technology, and in particular to a diamond particle coating liquid, a preparation method thereof, and a connection assembly. Background Art

[0002] It is common for sliding wear to occur between the mating surfaces of the connected parts and further develop into connection failure such as bolt loosening and breaking. Especially when the connected structure is subjected to large external loads, sliding wear can easily lead to damage to the paint film of the connected parts and cause local rust. If it continues to develop, the combined effect of higher dynamic tensile stress and micro-motion wear will cause micro-motion fatigue cracking of the connected parts, or the bolts may become loose or fatigue-fractured due to the abnormal dynamic stress, and other serious consequences. Summary of the invention

[0003] The present application provides a diamond particle coating liquid and a preparation method thereof and a connection assembly to solve the problem of sliding wear between the joint surfaces of existing connection parts and further development to bolt loosening and breaking.

[0004] In a first aspect, the present application provides a diamond particle coating liquid, the raw materials of which include:

[0005] Diamond particles, dispersants, film formers, corrosion inhibitors, coupling agents and solvents;

[0006] Wherein, the coupling agent includes at least one of a titanate coupling agent, an aluminate coupling agent, and a silane coupling agent.

[0007] The present application adds a coupling agent to the diamond particle coating liquid so that the diamond particles have strong bonding properties and can form a tight connection with the connected parts when coating the connected surface. There is no need to use a high-viscosity adhesive or form a thick coating, so that the diamond particles do not need to be encapsulated inside the coating, so that the fully exposed diamond particles can be embedded in the connected parts, avoiding sliding wear between the first connected part and the second connected part, and reducing problems such as bolt loosening and breaking.

[0008] It should be noted that at least one of titanate coupling agent, aluminate coupling agent and silane coupling agent has the advantage of enhancing the bonding force between diamond and film layer compared with other types of coupling agents. In addition, due to the widespread bonding ability between coupling agent and various materials, the surface of the joint surface of the connected part can be bare metal, or it can be an anodic protective coating layer such as a galvanized layer, or a common paint coating layer. By utilizing the chemical bonding mechanism of the coupling agent, a coupling agent coating layer with strong adhesion but thin thickness can be formed on the installation joint surface, so that the tip of the diamond particle is fully exposed, which is conducive to the diamond particle fully embedding / biting into the material of the joint surface of the connected part. Usually, a layer of coupling agent is pre-coated on the connecting part, and then a diamond particle coating liquid is coated on the surface of the coupling agent to improve the connection firmness between the diamond particles and the connecting part.

[0009] In some embodiments, the mass proportion of the diamond particles in the diamond particle coating liquid is 10-30%. The mass proportion of the diamond particles in the diamond particle coating liquid within this range can make the area proportion of the diamond particles reach 10%-80% after the diamond particle coating liquid forms a coating, thereby increasing the friction between the connecting member and the connected member and reducing the sliding wear between the connecting member and the connected member; and / or,

[0010] The mass proportion of the coupling agent in the diamond particle coating liquid is 3% to 5%. When the mass proportion of the coupling agent in the diamond particle coating liquid is within this range, the firmness of the bonding between the diamond particles and the connecting member can be improved, the thickness of the coating can be further reduced, so that the diamond particles are exposed and protrude from the surface of the coating, and are more easily embedded in the connected member, thereby increasing the friction coefficient between the connecting member and the connected member and reducing sliding wear; and / or,

[0011] The particle size of the diamond particles is 5 to 60 μm. Within this range, the diamond particles are more easily exposed to the coating surface, making it easier for the diamond particles to be embedded in the connected parts, thereby increasing the friction coefficient between the connecting parts and the connected parts and reducing sliding wear.

[0012] In some embodiments, the mass ratio of the dispersant, film former, corrosion inhibitor and solvent is (10-25): (28-40): (0.5-1): (30.6-36). When the mass ratio of the dispersant, film former, corrosion inhibitor and solvent is within this range, the viscosity of the diamond particle coating liquid can be smaller, the thickness of the formed coating can be smaller, and the diamond particles are more likely to be exposed to the surface of the coating, so that the diamond particles are more easily embedded in the connected parts, the friction coefficient between the connecting parts and the connected parts is increased, and the sliding wear is reduced. It should be noted that due to the addition of the coupling agent, the amount of the film former added will not be too high, thereby achieving the control of the coating thickness.

[0013] In some embodiments, the dispersant includes at least one of sodium petroleum sulfonate, sodium oleate, and sodium phthalate. By using at least one of the above dispersants, various components can be fully dispersed and the dispersion performance of diamond during the stirring process can be enhanced; and / or,

[0014] The film-forming agent includes at least one of monoglycerol fatty acid ester and propylene glycol methyl ether acetate. By using at least one of the above film-forming agents, a thin and dense film layer can be formed on the surface of the part; and / or,

[0015] The corrosion inhibitor includes at least one of benzotriazole, phosphine carboxylic acid, and mercaptobenzothiazole. Using at least one of the above corrosion inhibitors can reduce corrosion on the surface of parts and improve the anti-rust performance when coating on the bare surface of parts; and / or,

[0016] The solvent includes at least one of poly-alpha olefin synthetic oil, carboxylate synthetic oil, and ester synthetic oil. Using at least one of the above solvents can provide a stable dispersion environment and rapid drying performance.

[0017] In some embodiments, the raw materials also include colorants. Usually, dispersants, film formers, corrosion inhibitors and solvents are transparent and colorless. It is not easy to see whether the coating is complete during coating, and it is difficult to observe the coating area. Therefore, colorants can be added to the diamond particle coating liquid for coloring, so that the coating formed by the coating is easier to identify and easier to judge whether the coating is complete. Bright colors, such as yellow, red, blue, green, purple, orange and other colors of colorants can be used. At the same time, in order to reduce the impact of the colorant on the entire diamond particle coating liquid system, an azo type colorant can be selected. At the same time, the mass proportion of the colorant in the entire diamond particle coating liquid can be 0.3% to 0.5%.

[0018] In a second aspect, the present application provides a method for preparing a diamond particle coating liquid, comprising the following steps:

[0019] Mixing a dispersant, a film-forming agent, a corrosion inhibitor and a solvent to obtain a first mixed solution;

[0020] mixing the diamond particles with the coupling agent to obtain a second mixed solution;

[0021] The first mixed liquid is mixed with the second mixed liquid to obtain a diamond particle coating liquid.

[0022] By mixing the diamond particles with the coupling agent to obtain the second mixed liquid, the diamond particles can be fully coupled, which is beneficial for the diamond particles to be firmly adhered to the bonding surface of the connected parts, so that the viscosity of the diamond particle coating liquid can be smaller, the thickness of the formed coating is smaller, and it is more beneficial for the diamond particles to be exposed to the surface of the coating, making it easier for the diamond particles to be embedded in the connected parts, thereby increasing the friction coefficient between the first connected part and the second connected part and reducing sliding wear.

[0023] In some embodiments, the step of mixing the diamond particles with the coupling agent to obtain the second mixed solution comprises:

[0024] Mixing diamond particles with an excess of coupling agent to obtain a premixed solution;

[0025] The premixed solution is stirred, allowed to stand, and separated into layers, and excess coupling agent in the upper layer is separated to obtain a second mixed solution.

[0026] By mixing diamond particles with an excess of coupling agent, stirring the premixed liquid, standing it, layering it, and separating the excess coupling agent in the upper layer to obtain a second mixed liquid, the diamond particles can be evenly and fully coupled, which is conducive to firmly adhering the diamond particles to the bonding surface of the connected parts, so that the viscosity of the diamond particle coating liquid can be smaller, the thickness of the formed coating is smaller, and it is more conducive to exposing the diamond particles to the surface of the coating, making it easier for the diamond particles to be embedded in the interior of the connected parts, thereby increasing the friction coefficient between the first connected part and the second connected part and reducing sliding wear.

[0027] In some embodiments, the step of mixing the first mixed liquid with the second mixed liquid to obtain the diamond particle coating liquid comprises:

[0028] Mixing the first mixed solution with the second mixed solution to obtain a third mixed solution;

[0029] The third mixed liquid is mixed with a colorant to obtain a diamond particle coating liquid.

[0030] Adding colorants to the diamond particle coating liquid for coloring makes the coating formed by the coating easier to identify and easier to judge whether the coating is complete. Adding colorants at the end has the advantage of avoiding interference with the coloring effect caused by the previous addition process and ensuring that the color of the film layer is the desired color.

[0031] In the third aspect, the present application provides a connection assembly, including a first connected part and a second connected part, wherein the first connected part has a first contact surface, the second connected part has a second contact surface, the first contact surface and the second contact surface are in abutment, and a coating is provided on the first contact surface and / or the second contact surface, and the coating is formed by coating the diamond particle coating liquid described in the first aspect. Since the diamond particles are exposed outside the coating, it is usually only necessary to form a coating on the first contact surface or the second contact surface to increase the friction force, which can reduce the cost. Under certain special working conditions, a coating can also be provided on both the first contact surface and the second contact surface. Further increase the friction force and reduce sliding wear. Usually, after the coating is formed, a large axial force can be applied by connecting bolts to embed the exposed diamond particles in the coating into the connected part, thereby achieving the purpose of increasing the friction coefficient. The coating formed by coating with diamond particle coating liquid is used for various joint surfaces of connected parts, including different surface states and different shape contours. It can be pre-coated for mass-produced connected parts, or it can be coated on the spot for maintenance scenes, without limiting the use scene.

[0032] In some embodiments, the coating film layer of the coating has a thickness of 0.3 to 10 μm, wherein the diamond is exposed to the coating film layer. A coupling agent is added to the diamond particle coating liquid so that the diamond particles have strong bonding properties and can form a tight connection with the connection surface when coated on the connection surface. There is no need to use a high-viscosity adhesive and there is no need to form a thick coating, so that the diamond particles do not need to be coated inside the coating, so that the diamond particles fully exposed to the coating film layer can be embedded inside the connected part. The minimum thickness of the coating film layer is only 0.3 μm to achieve reliable adhesion and full exposure of the diamond particles, so that the coating has a better effect of increasing the friction coefficient. It should be noted that the method of forming the coating can be local dipping, spraying or brushing, which is selected according to the shape of the first contact surface and the second contact surface. This application will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 This is a structural schematic diagram of the connection interface of the bolt connection structure of the prior art of this application.

[0035] Figure 2 This is a schematic diagram of sliding wear between the joint surfaces of the connected parts of the bolt connection structure of the prior art of this application.

[0036] Figure 3 This is a schematic diagram of the structure of the connection component of Example 4 of the present application.

[0037] Figure 4 This is an enlarged view of the diamond particle coating liquid coating on the bonding surface of Example 4 of the present application.

[0038] Figure 5 This is a schematic diagram of the structure of the connection component of Example 5 of the present application.

[0039] Figure 6 This is a schematic diagram of the structure of the connection component of Example 6 of the present application. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0041] Bolt connections are widely used in automobiles and various mechanical structures. Typical bolt connections are: Figure 1 As shown, it is composed of bolts, nuts and two or more connected parts. There is a mating surface between the two connected parts. Loosening is a common failure mode of bolted connections. Typical causes of bolted connection loosening include: (1) the bolts and nuts rotate in the loosening direction due to severe vibration; (2) the mating surface of the connected parts fails due to insufficient sliding resistance, such as sliding and wear. In order to prevent the rotational loosening of bolts and nuts due to vibration, various forms of anti-loosening nuts, anti-loosening bolts, and anti-loosening washers are available on the market, such as non-metallic insert locking nuts, metal insert locking nuts, local deformation interference locking nuts, wedge-shaped threaded nuts, eccentric double nuts, rubber-coated bolts, end-tooth bolts, serrated washers, spring washers, conical elastic washers, double-stack locking washers, etc. However, since these special fasteners are mainly used to prevent the vibration rotational loosening of bolts and nuts, they can only solve some of the loosening problems of bolted connections.

[0042] It is also common for the connection failure to occur between the joint surfaces of the connector and the connected parts, and further develop into bolt loosening and breaking, especially when the connection structure is subjected to large external loads, such as Figure 2As shown in the figure, due to the use of effective torque type all-metal locking nuts, there is no sign of looseness between the nut and the bolt, or between the nut and the connected parts, but there is obvious sliding wear between the two connected parts. This sliding wear has caused the paint film of the connected parts to be damaged and local rust to occur; if it continues to develop, it will also cause serious consequences such as fretting fatigue cracking of the connected parts due to the combined effect of high dynamic tensile stress and fretting wear, or fatigue fracture of the bolts due to abnormal dynamic stress.

[0043] In order to avoid slippage of the mating surfaces of the connected parts, on the one hand, the mating surface pressure under service conditions can be increased by increasing the bolt specifications, increasing the number of bolts, applying a larger initial preload of the bolts, controlling the attenuation factor of the bolt axial force, etc. On the other hand, the apparent friction coefficient of the mating surfaces of the connected parts needs to be increased.

[0044] The reference friction coefficient of the machined surface without surface coating has a wide distribution range, with a minimum of 0.04 and a maximum of 0.52; among them, the reference friction coefficient of the dry and unlubricated steel-aluminum machined joint surface is 0.07-0.28, and the maximum value is 4 times the minimum value, with a wide distribution range. In practical applications, in order to prevent rust and other needs, there will be various metal or non-metal coating layers on the surface of parts, such as electroplating, paint, anti-rust oil, lubricating oil, etc., which will further increase the distribution range of the friction coefficient of the joint surface, with a lower lower limit and a higher upper limit.

[0045] In order to improve the friction coefficient of the joint surface of the connected parts, measures such as controlling the surface conditions of the connected parts can be adopted, such as coating adhesive on the joint surface, shot peening the joint surface, knurling the joint surface, etc., so as to obtain a higher and more stable friction coefficient. However, these measures have problems such as limited effect or conflict with other requirements.

[0046] For example, a fastening structure introduces hard particles such as silicon carbide and diamond on the joint surface of the connected parts. The hard particles are embedded in the surface of the connected parts under the clamping force of the bolts, thereby obtaining a higher friction coefficient. In order to solve the problem of the adhesion of hard particles on the joint surface of the connected parts, the patent proposes that "the abrasive retaining layer is formed by coating anti-rust wax containing abrasives", or "the abrasive retaining layer is made of a metal gasket and abrasives arranged on the two surfaces of the metal gasket through an adhesive". However, the thickness of the anti-rust wax coating itself is relatively thick, so a larger diamond particle size is required to ensure that the abrasive particles such as diamond have a sufficiently large tip protrusion, which will lead to an increase in coating costs and a greater impact on the dimensional accuracy of the original structure. The main function of the anti-rust wax is to prevent rust, and its bonding strength with metal components and diamond surfaces needs to be improved. The anti-rust wax itself may also reduce the friction coefficient of the joint surface.

[0047] A method for producing a diamond chemical composite plated automobile friction gasket, the method comprising chemically composite-plating a Ni-P-micron diamond coating on a thin spring steel gasket, and then performing a heat treatment at 150°C to 350°C; a two-step plating method is adopted, in which a Ni-P layer is plated on the steel gasket in the first step, and a Ni-P-micron diamond coating is continuously plated on the Ni-P coating in the second step, wherein the diamond in the coating is in a semi-naked state; in a working state, the diamond particles in the coating are automatically embedded in the opposite surface to form a micro interlocking, thereby increasing the friction force. However, the friction gasket needs to use the gasket material and the nickel-phosphorus coating as carriers, and both planes of the gasket need to be coated with the Ni-P-micron diamond coating, which increases the application cost. The Ni-P-micron diamond plating process is relatively complex and has some special requirements, such as: pre-treatment is crucial to the quality of the coating, the workpiece surface must be free of pollution and in an activated state before plating; acid pickling activation is required; the workpiece needs to be rinsed with hot deionized water; the plating solution needs to be heated; there must be moderate light stirring during the plating process; heating and baking are required after plating. Therefore, the process cost of this solution is relatively high. The relatively thick nickel-phosphorus coating will limit the height of the diamond particle tip protruding from the coating, thereby adversely affecting the depth of the diamond particle tip biting into the connected parts. Adding a gasket between the connected parts will change the original structural size matching relationship and limit the scope of application. The gasket has poor adaptability to the complex mounting surface contour, which limits the rapid application and application scope. The gasket brings new geometric tolerance problems, such as the thickness difference of the gasket has an adverse effect on the overall flatness of a set of mounting bosses, and the problem of the accumulation of the gasket geometric tolerance and the geometric tolerance of the connected parts.

[0048] In view of this, the present application provides a diamond particle coating liquid and a preparation method thereof and a connection assembly to solve the problem of sliding wear between the joint surfaces of existing connectors and further development to bolt loosening and breaking.

[0049] In a first aspect, the present application provides a diamond particle coating liquid, the raw materials of which include:

[0050] Diamond particles, dispersants, film formers, corrosion inhibitors, coupling agents and solvents;

[0051] Wherein, the coupling agent includes at least one of a titanate coupling agent, an aluminate coupling agent, and a silane coupling agent.

[0052] The present application adds a coupling agent to the diamond particle coating liquid, so that the diamond particles have strong bonding properties, and can form a tight connection with the connecting parts when coated on the connecting surface, without the need to use a high-viscosity adhesive, and without the need to form a thick coating, so that the diamond particles do not need to be coated inside the coating, so that the fully exposed diamond particles can be embedded inside the connected parts, reducing the sliding wear between the connecting parts and the connected parts, and reducing the problems of bolt loosening and breaking. After the diamond particle coating liquid of the present application forms a coating, the coating thickness is small, the diamond particle exposure area is large, the bonding force is strong, and the process is simple.

[0053] It should be noted that at least one of titanate coupling agent, aluminate coupling agent and silane coupling agent has the advantage of enhancing the bonding force between diamond and film layer compared with other types of coupling agents. In addition, due to the widespread bonding ability between coupling agent and various materials, the surface of the joint surface of the connected part can be bare metal, or it can be an anodic protective coating layer such as a galvanized layer, or a common paint coating layer. By utilizing the chemical bonding mechanism of the coupling agent, a coupling agent coating layer with strong adhesion but thin thickness can be formed on the installation joint surface, so that the tip of the diamond particle is fully exposed, which is conducive to the diamond particle fully embedding / biting into the material of the joint surface of the connected part. Usually, a layer of coupling agent is pre-coated on the connected part, and then a diamond particle coating liquid is coated on the surface of the coupling agent to improve the connection firmness between the diamond particles and the connecting part.

[0054] In combination with the first aspect, in some embodiments provided in the present application, the mass proportion of the diamond particles in the diamond particle coating liquid is 10-30%. The mass proportion of the diamond particles in the diamond particle coating liquid is within this range, so that after the diamond particle coating liquid forms a coating, the area proportion of the diamond particles reaches 10%-80%, thereby increasing the friction between the two connected parts and reducing the sliding wear between the two connected parts.

[0055] In combination with the first aspect, in some embodiments provided in the present application, the coupling agent accounts for 3% to 5% by mass in the diamond particle coating liquid. When the coupling agent accounts for 3% to 5% by mass in the diamond particle coating liquid, the firmness of the bond between the diamond particles and the connecting parts can be improved, and the thickness of the coating can be further reduced, so that the diamond particles are exposed and protrude from the surface of the coating, making it easier to embed into the connected parts, thereby improving the friction coefficient between the two connected parts and reducing sliding wear.

[0056] In combination with the first aspect, in some embodiments provided in the present application, the particle size of the diamond particles is 5 to 60 μm. Within this particle size range, the diamond particles are more easily exposed to the coating surface, making it easier for the diamond particles to embed into the connected parts, thereby increasing the friction coefficient between the two connected parts and reducing sliding wear.

[0057] In combination with the first aspect, in some embodiments provided in the present application, the mass ratio of the dispersant, film former, corrosion inhibitor and solvent is (10-25): (28-40): (0.5-1): (30.6-36). The mass ratio of the dispersant, film former, corrosion inhibitor and solvent within this range can make the viscosity of the diamond particle coating liquid smaller, the thickness of the formed coating smaller, and it is more conducive to the exposure of the diamond particles to the surface of the coating, so that the diamond particles are more easily embedded in the connected parts, the friction coefficient between the two connected parts is increased, and the sliding wear is reduced. It should be noted that due to the addition of the coupling agent, the amount of the film former added will not be too high, thereby achieving the control of the coating thickness.

[0058] In combination with the first aspect, in some embodiments provided in the present application, the dispersant includes at least one of sodium petroleum sulfonate, sodium oleate, and sodium phthalate. By using at least one of the above dispersants, the various components can be fully dispersed and the dispersion performance of diamond during the stirring process can be enhanced.

[0059] In combination with the first aspect, in some embodiments provided in the present application, the film-forming agent includes at least one of monoglycerol fatty acid ester and propylene glycol methyl ether acetate. By using at least one of the above film-forming agents, a thin and dense film layer can be formed on the surface of the part.

[0060] In combination with the first aspect, in some embodiments provided in the present application, the corrosion inhibitor includes at least one of benzotriazole, phosphine carboxylic acid, and mercaptobenzothiazole. The use of at least one of the above corrosion inhibitors can reduce corrosion on the surface of parts and improve the anti-rust performance when coating on the bare surface of parts.

[0061] In combination with the first aspect, in some embodiments provided in the present application, the solvent includes at least one of polyalphaolefin synthetic oil, carboxylate synthetic oil, and ester synthetic oil. Using at least one of the above solvents can provide a stable dispersion environment and fast drying performance.

[0062] In combination with the first aspect, in some embodiments provided in the present application, the raw materials also include a colorant. Usually, dispersants, film formers, corrosion inhibitors and solvents are all transparent and colorless. It is not easy to see whether the coating is complete during coating, and it is difficult to observe the coating area. Therefore, a colorant can be added to the diamond particle coating liquid for coloring, so that the coating formed by the coating is easier to identify and easier to judge whether the coating is complete. Bright colors such as yellow, red, blue, green, purple, orange and other colors of colorants can be used. At the same time, in order to reduce the influence of the colorant on the entire diamond particle coating liquid system, an azo type colorant can be selected, and the mass proportion of the colorant in the entire diamond particle coating liquid can be 0.3% to 0.5%.

[0063] In a second aspect, the present application provides a method for preparing a diamond particle coating liquid, comprising the following steps:

[0064] Mixing a dispersant, a film-forming agent, a corrosion inhibitor and a solvent to obtain a first mixed solution;

[0065] mixing the diamond particles with the coupling agent to obtain a second mixed solution;

[0066] The first mixed liquid is mixed with the second mixed liquid to obtain a diamond particle coating liquid.

[0067] By mixing the diamond particles with the coupling agent to obtain the second mixed liquid, the diamond particles can be fully coupled, which is conducive to firmly adhering the diamond particles to the bonding surface of the connected parts, so that the viscosity of the diamond particle coating liquid can be smaller, the thickness of the formed coating is smaller, and it is more conducive to exposing the diamond particles to the surface of the coating, making it easier for the diamond particles to be embedded in the connected parts, thereby increasing the friction coefficient between the two connected parts and reducing sliding wear.

[0068] In conjunction with the second aspect, in some embodiments provided in the present application, the step of mixing the diamond particles with the coupling agent to obtain the second mixed solution comprises:

[0069] Mixing diamond particles with an excess of coupling agent to obtain a premixed solution;

[0070] The premixed solution is stirred, allowed to stand, and separated into layers, and excess coupling agent in the upper layer is separated to obtain a second mixed solution.

[0071] By mixing diamond particles with an excess of coupling agent, stirring the premixed liquid, standing it, layering it, and separating the excess coupling agent in the upper layer to obtain a second mixed liquid, the diamond particles can be evenly and fully coupled, which is conducive to firmly adhering the diamond particles to the bonding surface of the connected parts, so that the viscosity of the diamond particle coating liquid can be smaller, the thickness of the formed coating is smaller, and it is more conducive to exposing the diamond particles to the surface of the coating, making it easier for the diamond particles to be embedded in the connected parts, thereby increasing the friction coefficient between the two connected parts and reducing sliding wear.

[0072] In conjunction with the second aspect, in some embodiments provided in the present application, mixing the first mixed liquid with the second mixed liquid to obtain the diamond particle coating liquid comprises:

[0073] Mixing the first mixed solution with the second mixed solution to obtain a third mixed solution;

[0074] The third mixed liquid is mixed with a colorant to obtain a diamond particle coating liquid.

[0075] Coloring the diamond particle coating liquid by adding a colorant makes the coating formed by the coating easier to identify and easier to judge whether the coating is complete. Adding the colorant at the end has the advantage of avoiding interference with the coloring effect caused by the previous addition process and ensuring that the color of the film layer is the desired color. Specifically, the stirring speed can be 1000 to 2000 rpm for 15 to 30 minutes to allow the diamond particles to be fully coupled.

[0076] In the third aspect, the present application provides a connection assembly, including a first connected part and a second connected part, wherein the first connected part has a first contact surface, the second connected part has a second contact surface, the first contact surface and the second contact surface are in abutment, and a coating is provided on the first contact surface and / or the second contact surface, and the coating is formed by coating the diamond particle coating liquid described in the first aspect. Since the diamond particles are exposed outside the coating, it is usually only necessary to form a coating on the first contact surface or the second contact surface to increase the friction force, which can reduce the cost. Under certain special working conditions, a coating can also be provided on both the first contact surface and the second contact surface. Further increase the friction force and reduce sliding wear. Usually, after the coating is formed, a large axial force can be applied by connecting bolts to embed the exposed diamond particles in the coating into the connected part, thereby achieving the purpose of increasing the friction coefficient. The coating formed by coating with diamond particle coating liquid is used for various joint surfaces of connected parts, including different surface states and different shape contours. It can be pre-coated for mass-produced connected parts, or it can be coated on the spot for maintenance scenes, without limiting the use scene.

[0077] It should be noted that since the diamond particle coating liquid is not a stable and uniform system, in order to improve the uniformity of the coating layer during coating, the diamond particle coating liquid needs to be stirred all the time, for example, coating is performed at a stirring speed of 200 rpm to achieve uniformity of the entire suspension system.

[0078] In conjunction with the third aspect, in some embodiments provided in the present application, the coating film layer of the coating has a thickness of 0.3 to 10 μm, wherein the diamond is exposed to the coating film layer. A coupling agent is added to the diamond particle coating liquid, so that the diamond particles have strong connection properties, and can form a tight connection with the connecting part when applied to the connecting surface, without the need to use a high-viscosity adhesive, and without the need to form a thicker coating, so that the diamond particles do not need to be coated inside the coating, so that the fully exposed diamond particles can be embedded inside the connected part, and the minimum thickness of the coating film layer is only 0.3 μm to achieve reliable adhesion and full exposure of the diamond particles, so that the coating has a better effect of increasing the friction coefficient. It should be noted that the method of forming the coating can be local dipping, spraying or brushing, which is selected according to the shape of the first contact surface and the second contact surface, and the present application will not repeat them one by one here.

[0079] The technical solution provided in this application is described in detail below with reference to the embodiments and drawings.

[0080] Example 1

[0081] Example 1 of the present application provides a diamond particle coating liquid, including the following raw materials:

[0082] Diamond particles, sodium petroleum sulfonate, monoglycerol fatty acid ester, benzotriazole, polyalphaolefin synthetic oil and titanate coupling agent, of which:

[0083] The particle size of the diamond particles is 25 μm, and the mass proportion of the diamond particles in the diamond particle coating liquid is 10%;

[0084] The mass ratio of sodium petroleum sulfonate, monoglycerol fatty acid ester, benzotriazole and dodecenylsuccinic acid is 10:28:0.5:30.6;

[0085] The mass proportion of the titanate coupling agent in the diamond particle coating liquid is 3%.

[0086] Example 2

[0087] Example 2 of the present application provides a diamond particle coating liquid, comprising the following raw materials:

[0088] Diamond particles, sodium petroleum sulfonate, propylene glycol methyl ether acetate, benzotriazole, carboxylic acid ester synthetic oil and titanate coupling agent, including:

[0089] The particle size of the diamond particles is 45 μm, and the mass proportion of the diamond particles in the diamond particle coating liquid is 20%;

[0090] The mass ratio of sodium petroleum sulfonate, propylene glycol methyl ether acetate, benzotriazole and carboxylic acid ester synthetic oil is 20:35:0.8:35;

[0091] The mass proportion of the coupling agent in the diamond particle coating liquid is 4%.

[0092] Example 3

[0093] Example 3 of the present application provides a diamond particle coating liquid, including the following raw materials:

[0094] Diamond particles, sodium phthalate, monoglycerol fatty acid ester, phosphine carboxylic acid, ester synthetic oil and aluminate coupling agent, of which:

[0095] The particle size of the diamond particles is 60 μm, and the mass proportion of the diamond particles in the diamond particle coating liquid is 30%;

[0096] The mass ratio of sodium phthalate, monoglycerol fatty acid ester, phosphine carboxylic acid and ester synthetic oil is 25:40:1:36;

[0097] The mass proportion of the coupling agent in the diamond particle coating liquid is 5%.

[0098] Example 4

[0099] Embodiment 4 of the present application provides a connection assembly, a pulley bearing inner ring and a support bolt connection assembly, because the connection interface is subjected to a large lateral load, the connection interface slides and causes the bolts to loosen and break, and the connection fails, and a diamond particle friction-enhancing layer is coated on the installation interface. Figure 3 As shown, the pulley is radially connected to the outer ring of the bearing by an interference fit, and the inner ring of the bearing is connected to the pulley mounting support by bolts. The location where the initial sliding occurs is the connection interface between the inner ring of the bearing and the support, that is, the connecting surface of the connected part. The material of the inner ring of the bearing of the first connected part is GCr15, and the heat treatment hardness is about 60HRC. The surface of its mounting surface is ground, and the roughness is Ra0.4, without other coating layers; the material of the support of the second connected part is ductile iron QT500, with a hardness of about 200HB, and the surface of its mounting surface is turned, and the roughness is Ra1.6-Ra3.2, without other coating layers. The friction coefficient between the two connecting parts mounting surfaces is 0.10-0.23 (minimum 0.10). The diamond particle coating liquid of Example 1 is used to coat a diamond particle friction-increasing layer on the connecting interface of the inner ring of the bearing of the first connected part, as shown in FIG. Figure 4As shown, the thickness of the continuous covering film layer is about 5μm, and the thickness of the diamond particle dispersion layer embedded in the continuous covering film layer and exposed at the tip above the continuous covering film layer is about 25μm. The M16-12.9 grade bolts used in the connection structure are tightened to the yield point by the torque angle method, and the diamond particles are embedded in the end face of the inner ring of the connected bearing and the end face of the connected support. The minimum value of the friction coefficient of the joint surface is increased from ≥0.1 to ≥0.35, and the safety factor of the joint surface against lateral slip is greatly improved.

[0100] Example 5

[0101] Embodiment 5 of the present application provides a connection assembly, in which a pin is connected to a support bolt. The pin at the end of the support beam and the support bolt connection bear a large lateral load, and the connection interface slides and causes the support to be severely worn and the bolt to break. Therefore, a diamond particle friction-enhancing layer is coated on the installation interface. Figure 5 As shown, the pin is connected to the end support of the support beam through bolts and nuts. The initial sliding occurs at the joint surface between the pin and the support, that is, the joint surface of the connected part. The material of the pin of the connected part is 40Cr, the heat treatment hardness is about 40HRC, the surface of its installation joint surface is sandblasted, the roughness is Ra3.2-Ra6.3, and the outer surface is covered with a phosphating layer with a thickness of about 2 microns; the material of the support of the connected part is ductile iron QT600, the hardness is about 230HB, the surface of its installation joint surface is milled, the roughness is Ra3.2-Ra6.3, and the outer surface is covered with electrophoretic paint with a thickness of about 25 microns. The friction coefficient between the installation joint surfaces of the two connected parts is 0.15-0.25. The diamond particle coating liquid of Example 2 is coated on the mounting joint surface of the pin shaft of the connected part, and the thickness of the covering film layer is about 6 μm. The thickness of the diamond particle dispersion layer embedded in the continuous covering film layer and the tip exposed above the continuous covering film layer is about 45 μm. The M20-10.9 grade bolts used in the connection structure are tightened to an axial preload of ≥109 kN, and the diamond particles are embedded in the mounting joint surface of the connecting part-pin shaft and the mounting joint surface of the connected part-support. The minimum value of the friction coefficient of the joint surface is increased from ≥0.15 to ≥0.40, and the safety factor of the joint surface against lateral slip is greatly improved.

[0102] Example 6

[0103] Embodiment 6 of the present application provides a connection assembly, in which a large bracket is bolted to a longitudinal beam of a vehicle frame. The bolted connection between the large bracket and the longitudinal beam of the vehicle frame is subjected to a large lateral load, and the connection joint surface slides and causes the paint film to wear and the bolts to loosen and fail. Therefore, a diamond particle friction-enhancing layer is coated on the installation joint surface. Figure 6As shown, the large bracket shown is connected to the frame longitudinal beam by bolts and nuts. The initial sliding occurs at the connection interface between the large bracket and the longitudinal beam, that is, the connection interface of the connected part. The material of the large bracket of the connected part is ductile iron QT600, with a hardness of about 230HB. The surface of its installation interface is milled, with a roughness of Ra3.2-Ra6.3, and the outer surface is covered with electrophoretic paint with a thickness of about 25 microns; the material of the connected part - the frame longitudinal beam is a steel plate for the beam, with a hardness of about 220HB, and its surface state is cold rolled + powder sprayed, and the thickness of the powder spray paint film layer is about 100μm. The friction coefficient between the installation interfaces of the two connected parts is 0.05-0.10. The diamond particle coating liquid of Example 3 is coated on the installation joint surface of the large bracket of the connected part, and the thickness of the covering film layer is about 9 μm. The thickness of the diamond particle dispersion layer embedded in the continuous covering film layer and the tip exposed above the continuous covering film layer is about 60 μm. The M18-10.9 grade bolts used in the connection structure are tightened to an axial preload of ≥85 kN, and the diamond particles are embedded in the installation joint surface of the connecting part-large bracket and the installation joint surface of the connected part-frame longitudinal beam. The minimum value of the friction coefficient of the joint surface is increased from ≥0.05 to ≥0.25, and the safety factor of the joint surface against lateral slip is greatly improved.

[0104] Comparative Example 1

[0105] The same diamond particles as those in Example 1 of the present application were used, with a particle size of approximately 25 μm, and the mass proportion of the diamond particles in the diamond particle coating liquid was 10%; the difference was that the diamond particles in Comparative Example 1 were dispersed in the anti-rust wax by stirring, and did not contain a coupling agent (SP-WAX-160 anti-rust wax, produced by Shenyang Parker Precision Co., Ltd.) to form a diamond particle coating liquid.

[0106] Comparative Example 2

[0107] Comparative Example 2 of the present application provides a connection assembly, a pulley bearing inner ring and a support bolt connection assembly, because the connection interface is subjected to a large lateral load, the connection interface slides and causes the bolts to loosen and the bolts to break. The connection failure phenomenon, a diamond particle friction-increasing layer is coated on its installation interface. The pulley is radially connected to the bearing outer ring by an interference fit, and the bearing inner ring is connected to the pulley mounting support by bolt connection. The initial sliding part is the connection interface between the bearing inner ring and the support, that is, the connection interface of the connected part. The material of the first connected part bearing inner ring is GCr15, the heat treatment hardness is about 60HRC, the surface of its installation interface is ground, the roughness is Ra0.4, and there is no other coating layer; the material of the second connected part support is ductile iron QT500, the hardness is about 200HB, the surface of its installation interface is turned, the roughness is Ra1.6-Ra3.2, and there is no other coating layer. The friction coefficient between the first connected part and the second connected part installation interface is 0.10-0.23 (minimum 0.10). The diamond particle coating liquid of Comparative Example 1 was used to spray the diamond particle coating liquid on the connection surface of the inner ring of the connector bearing. The thickness of the continuous covering film layer was about 30 μm. The M16-12.9 grade bolts used in the connection structure were tightened to the yield point by the torque angle method. The friction coefficient of the bonding surface was 0.12-0.20. The film thickness formed by the coating liquid of Comparative Example 1 was about 30 μm, and the particle size of the diamond particles was about 25 μm. The diamond particles could not be exposed, and the effect of significantly improving the friction coefficient could not be produced.

[0108] In summary, by adding a coupling agent to the diamond particle coating liquid, the diamond particles have strong bonding properties and can form a tight connection with the connecting parts when coated on the connecting surface. There is no need to use a high-viscosity adhesive or form a thick coating, so that the diamond particles do not need to be encapsulated inside the coating, so that the fully exposed diamond particles can be embedded in the connected parts, reducing the sliding wear between the connecting parts and the connected parts, and reducing problems such as bolt loosening and breakage.

[0109] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments / methods or examples. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0110] It should be noted that, in the present application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "comprise one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. In the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically stipulated.

[0111] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied for herein.

Claims

1. A diamond particle coating liquid, characterized in that: Its raw materials include: Diamond particles, dispersants, film formers, corrosion inhibitors, coupling agents and solvents; Wherein, the coupling agent includes at least one of a titanate coupling agent, an aluminate coupling agent, and a silane coupling agent.

2. The diamond particle coating liquid according to claim 1, characterized in that: The mass percentage of the diamond particles in the diamond particle coating liquid is 10 to 30%; and / or, The coupling agent accounts for 3% to 5% by mass in the diamond particle coating liquid; and / or, The particle size of the diamond particles is 5 to 60 μm.

3. The diamond particle coating liquid according to claim 1, characterized in that: The mass ratio of the dispersant, film-forming agent, corrosion inhibitor and solvent is (10-25): (28-40): (0.5-1): (30.6-36).

4. The diamond particle coating liquid according to claim 1, characterized in that: The dispersant includes at least one of sodium petroleum sulfonate, sodium oleate, and sodium phthalate; and / or, The film-forming agent includes at least one of monoglycerol fatty acid ester and propylene glycol methyl ether acetate; and / or, The corrosion inhibitor comprises at least one of benzotriazole, phosphine carboxylic acid and mercaptobenzothiazole; and / or, The solvent includes at least one of polyalphaolefin synthetic oil, carboxylate synthetic oil, and ester synthetic oil.

5. The diamond particle coating liquid according to claim 1, characterized in that: Its raw materials also include colorants.

6. A method for preparing a diamond particle coating liquid according to any one of claims 1 to 5, characterized in that: The following steps are involved: Mixing a dispersant, a film-forming agent, a corrosion inhibitor and a solvent to obtain a first mixed solution; mixing the diamond particles with the coupling agent to obtain a second mixed solution; The first mixed liquid is mixed with the second mixed liquid to obtain a diamond particle coating liquid.

7. The method for preparing a diamond particle coating liquid according to claim 6, wherein: The step of mixing the diamond particles with the coupling agent to obtain a second mixed solution comprises: Mixing diamond particles with an excess of coupling agent to obtain a premixed solution; The premixed solution is stirred, allowed to stand, and separated into layers, and excess coupling agent in the upper layer is separated to obtain a second mixed solution.

8. The method for preparing a diamond particle coating liquid according to claim 6, wherein: The step of mixing the first mixed liquid with the second mixed liquid to obtain a diamond particle coating liquid comprises: Mixing the first mixed solution with the second mixed solution to obtain a third mixed solution; The third mixed liquid is mixed with a colorant to obtain a diamond particle coating liquid.

9. A connection assembly, characterized in that: It comprises a first connecting member and a second connecting member, wherein the first connecting member has a first contact surface, the second connecting member has a second contact surface, the first contact surface is in abutment with the second contact surface, and the first contact surface and / or the second contact surface are provided with a coating, and the coating is formed by coating the diamond particle coating liquid as described in any one of claims 1 to 5.

10. The connection assembly according to claim 9, characterized in that The coating film layer of the coating has a thickness of 0.3 to 10 μm, wherein the diamond is exposed in the coating film layer.

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