Braking body and braking device

Abstract

The present invention provides a brake body having a coating comprising an iron-based amorphous alloy formed on the contact surface that generates braking force. The braking force is generated by friction between the rotating brake body and a friction unit. The coating has a low coefficient of friction, thus generating less dust during braking. Furthermore, due to its excellent corrosion resistance and wear resistance, it exhibits superior performance and price competitiveness when applied to brake substrates produced with low budgets.

Description

Technical Field

[0001] One aspect of the present invention relates to a braking device that can be used in a vehicle or drive unit, and a braking body included therein. Background Technology

[0002] Generally speaking, braking devices are a collective term for devices used to regulate and control the operating speed of vehicles or mechanical devices. Based on the mechanism that provides braking force, they are mainly divided into drum brakes and disc brakes.

[0003] The characteristic of a drum brake is that it uses fluid pressure to pressurize a piston, causing the brake shoe to be squeezed onto the brake drum along with the movement of the piston and applying braking force. However, due to its poor heat dissipation performance, most vehicles nowadays tend to use disc brakes, which have better heat dissipation performance than drum brakes.

[0004] A disc brake includes a body having a rotating body (disc) and brake pads for stopping the rotation of the rotating body. The disc brake can be used in braking systems for wind turbines, vehicles, and general (construction) machinery.

[0005] Braking systems used in vehicles are susceptible to problems such as corrosion, wear, and distortion, which can affect vehicle performance and occupant safety. For example, corrosion of friction surfaces can lead to noise and / or vibration during braking. Traditional cast iron brake discs are prone to such corrosion and are relatively heavy. In contrast, brake discs, which are lighter than cast iron brakes, can reduce unsprung weight and offer advantages such as improved vehicle handling. Therefore, it is expected that automotive brake discs with improved thermal, wear, and corrosion properties, as well as reduced weight, will continue to be researched and used.

[0006] As a method to improve corrosion and abrasion resistance and provide improved performance, improving surface properties through surface treatments such as coatings is simpler and more cost-effective than researching new materials that can be used for the brake discs themselves. Conventional processes for coating vehicle components include conventional heat treatments (e.g., ferritic-nitrocarburizing). Immersing cast iron brake discs in a salt bath produces a chemically modified surface with improved oxidation and corrosion resistance. However, this process requires heating and quenching all parts, potentially leading to thermal distortion. While this process can provide a coated surface for vehicle components, thermal distortion can adversely affect dimensional stability and scrap results during the process.

[0007] Other existing technologies offer methods for creating diffusion bonds between aluminum cores and stainless steel sheets. However, diffusion bonding presents technical challenges and limitations associated with the process. For example, the requirement for high-pressure rolling during diffusion bonding limits its application to flat brake discs. In contrast, processes applicable to materials and components of arbitrary shapes (e.g., rotors) would be efficient. Furthermore, diffusion typically requires prolonged periods of high heat and pressure. Additionally, time-efficient processes that do not require high pressure and transfer heat to a minimal area of ​​the substrate would be efficient. While these improvements are desirable, alternatives to diffusion bonding present additional challenges, such as those associated with using coated metals. For instance, related technologies have demonstrated the inability to produce satisfactory products due to peeling between the metal substrate and the sprayed metal; specifically, the sprayed metal may peel off inside the part, and, for example, the laminate prepared according to the diffusion bonding process may lack integrity.

[0008] Furthermore, the new coating method allows for the creation of new indicators for wear on vehicle components, such as brake rotor wear. For example, friction discs in related technologies feature a wear-resistant layer and an integrated wear indicator: when the wear-resistant layer wears, an indicator surface element with at least one distinguishing feature (color or texture) is exposed to indicate that the friction disc has been exposed. However, brake wear indicators are not directly integrated into the brake disc and require lengthy post-processing. The new coating method, which directly integrates the wear indicator into the metal, can provide significant efficiency, for example, in the manufacturing process. Summary of the Invention

[0009] Technical issues

[0010] According to one aspect of the present invention, the present invention aims to provide a brake body and a braking device including the brake body, the brake body having improved corrosion resistance and wear resistance, thereby reducing dust and particulate matter emissions and extending service life, thereby reducing manufacturing costs and being applicable to mass-produced vehicles, etc.

[0011] Solution

[0012] One aspect of the present invention provides a braking body disposed on a braking device.

[0013] The braking body includes: a coupling unit connected to a drive shaft; and a braking unit having a rotor connected to the outer peripheral surface of the coupling unit and a coating formed on the surface of the rotor, wherein the coating comprises an amorphous alloy and the coefficient of thermal expansion of the coating is 1.0 to 1.4 times that of the coefficient of thermal expansion of the rotor.

[0014] Preferably, the amorphous alloy comprises Fe and includes:

[0015] The first component, wherein the first component is at least one selected from Cr, Mo, and Co, and

[0016] The second component is at least one selected from B, C, Si, and Nb.

[0017] Preferably, the rotor comprises an iron-based alloy.

[0018] The average coefficient of friction of the coating, measured under 100N conditions, is preferably 0.001 to 0.08, and the Vickers hardness of the coating is preferably 700 Hv to 1200 Hv.

[0019] Furthermore, the coating preferably has a porosity of 0.1% to 1.0%.

[0020] The thickness of the coating is preferably 50 μm to 400 μm.

[0021] The coating is preferably formed by spraying iron-based amorphous alloy powder onto the rotor surface.

[0022] Preferably, in the braking body, the rotor is disc-shaped, and the coating is formed on at least one surface of the disc, or

[0023] The rotor is drum-shaped, and the coating is formed on the inner circumferential surface of the rotor.

[0024] Another aspect of the present invention provides a braking device for braking a drive mechanism including a drive shaft.

[0025] The braking device includes a braking body and a friction unit. The braking body includes a coupling unit and a braking unit. The coupling unit rotates in conjunction with the drive shaft during driving. The braking unit is connected to the outer peripheral surface of the coupling unit.

[0026] During braking, the friction unit displaces towards the braking body to contact it, and friction occurs between the friction unit and the braking body.

[0027] The braking unit includes a rotor connected to the coupling unit and a coating formed on the surface of the rotor. The coefficient of thermal expansion of the coating is 1.0 to 1.4 times that of the coefficient of thermal expansion of the rotor, and the coating comprises an amorphous alloy.

[0028] At this point, the amorphous alloy preferably contains Fe, and contains:

[0029] The first component is at least one selected from Cr, Mo and Co;

[0030] The second component is at least one selected from B, C, Si, and Nb.

[0031] The rotor preferably comprises an iron-based alloy.

[0032] The rotor is preferably disc-shaped, and the coating is formed on at least one surface of the rotor.

[0033] Alternatively, the rotor is preferably drum-shaped, and the coating is formed on the inner circumferential surface of the rotor.

[0034] Invention Effects

[0035] According to an embodiment of the present invention, an amorphous alloy coating is formed on the braking unit where friction occurs during braking. Therefore, it has a lower surface friction coefficient than conventional braking bodies, thereby preventing the generation of a large amount of dust and micro-dust during braking. Furthermore, the coating has improved wear resistance and corrosion resistance, thus improving the lifespan of the braking body.

[0036] Furthermore, when manufacturing brake bodies with coatings of amorphous alloys, the rotor of a mass-produced brake body can be used as the base material, as high-quality brake discs can be produced at a lower production cost, thus offering excellent price competitiveness.

[0037] Furthermore, in one embodiment of the present invention, an iron-based brake rotor is used as the substrate. Since an amorphous alloy coating with the same iron-based composition is formed, the coefficient of thermal expansion of the substrate and the coefficient of thermal expansion of the coating are in the approximate range of 1 to 1.4 times. Therefore, there are fewer peeling and defects caused by frictional heat, and it has the advantage of excellent bonding strength between the coating and the substrate surface.

[0038] Furthermore, since no additional intermediate or adhesive layers are required when forming the coating, it has the advantages of simplifying the process and saving production costs. Attached Figure Description

[0039] Figure 1 This is a schematic diagram illustrating a braking device according to an embodiment of the present invention.

[0040] Figure 2This is a schematic diagram illustrating the brake body of a braking device according to an embodiment of the present invention.

[0041] Figure 3 and Figure 4 This is a view showing the changes in the coating before and after a corrosion resistance test of an embodiment and a comparative example of the present invention. Detailed Implementation

[0042] Before describing the invention in detail below, it should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention, which is defined only by the appended claims. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art, unless otherwise stated.

[0043] In this regard, 1) the shapes, dimensions, proportions, angles, quantities, etc., shown in the accompanying drawings are schematic and can therefore be slightly modified. 2) since the accompanying drawings are displayed based on the observer's line of sight, the description of the direction or position of the accompanying drawings can be changed according to the observer's position. 3) the same reference numerals can be used for the same parts in different accompanying drawings.

[0044] 4) When using words such as "including," "having," or "consisting of," it indicates that other parts may be added, unless "only" is used to specify. 5) When described in the singular, it can be interpreted as plural. 6) Even if comparisons of shapes, sizes, or positional relationships are not described as "approximately" or "actually," they should be interpreted as including the usual range of error.

[0045] 7) Even when terms such as “after,” “before,” “next,” “following,” and “at this time” are used, it does not mean that these terms are used to specify the chronological or positional order. 8) Terms such as “first,” “second,” and “third” are used selectively, interchangeably, or repeatedly for the convenience of classification and should not be interpreted in a limiting sense.

[0046] 9) When using terms such as “above,” “over,” “below,” “beside,” “side,” or “between” to describe the positional relationship between two components, more than one component may be provided between the two components unless specified by a term such as “direct.” 10) When components are electrically connected by “~ or,” it should be interpreted as meaning that the components may be included individually and in combination; however, when components are electrically connected by “~ or, ~ one of them,” it should be interpreted as meaning that the components are connected individually.

[0047] The term "amorphous" in this specification includes the meaning of "non-crystalline" or "amorphous phase," and refers to a phase that does not crystallize in a solid, i.e., a phase that does not have a regular structure.

[0048] Furthermore, in this specification, iron-based amorphous alloy powder includes an alloy in powder form containing iron in the maximum weight proportion, and the amorphous phase in the powder substantially constitutes the majority.

[0049] As one aspect of the present invention, the brake body 10 includes: a coupling unit 200 coupled in a device or machine for coupling a rotating shaft or drive shaft of a wheel; and a brake unit 100 coupled to the outer peripheral surface of the coupling unit 200, wherein the coupling unit actually serves to connect the brake unit to the rotating shaft or drive shaft.

[0050] The shape of the brake body can vary depending on the type of device used, the shape of the braking device, and the method of braking. For example, a disc or drum shape with rotational symmetry relative to the central axis can be used. The brake body 10 is preferably disc or drum shaped.

[0051] Figure 1 This is a diagram showing the appearance of a braking device including a disc brake body 10 (brake disc). Figure 2 This is a diagram showing a brake body 10 according to one aspect of the present invention.

[0052] As an example of brake body 10, the brake disc is installed in a machine or vehicle including a drive shaft or axle (rotating shaft), such as an automobile, prime mover and other mechanical device.

[0053] The brake body 10 rotates together with the rotating drive shaft or axle. When the braking device is working, the rotating brake body 10 can rub against the friction unit 20 of the braking device on its surface. At this time, the brake body 10 loses rotational kinetic energy due to frictional resistance, and its rotational speed decreases to achieve braking.

[0054] The coupling unit 200 of the brake body 10, also known as the hub, is a component that connects to the drive shaft or axle of the wheel to allow the brake body 10 to rotate. The coupling unit 200 is coupled to and connected to the drive shaft or axle, so that the rotational kinetic energy generated by the automobile engine and transmitted to the wheel can be transmitted to the brake body 10.

[0055] The coupling unit 200 may include a body having fastening holes for engaging fastening devices such as nuts to engage with a drive shaft or axle; and a hat-part connected to the body and having a shape that protrudes from one side.

[0056] The engaging unit 200 of the brake body 10 has a circular outer peripheral surface. The size of the engaging unit 200 is not limited, but varies depending on the device or vehicle using the braking device and the size of the braking device.

[0057] In the brake body 10, the brake unit 100, which is coupled to the outer peripheral surface of the coupling unit 200, preferably includes a rotor disposed on the outer peripheral surface of the coupling unit 200 to rotate together with the drive shaft or axle; and a coating 110 formed on the surface of the rotor 120.

[0058] The rotor 120 is a component that rotates by receiving rotational kinetic energy transmitted from the drive shaft or axle to the brake body 10. It is typically used to form the appearance of the brake body 10, and its interior can be an annular shape with through holes or a cylindrical drum shape with through holes inside.

[0059] like Figure 2 As shown, according to one embodiment of the present invention, the brake body 10 is a disc brake body 10, wherein the rotor is an annular plate with a through hole inside, and the through hole located at the center of the rotor can be connected to the outer peripheral surface of the aforementioned connecting unit 200 on the inner circumferential surface of the circle.

[0060] Although not specifically shown in the accompanying drawings, in the rotor 120 of the braking unit 100, the inner circumferential surface of the rotor 120 can be integrally connected to the outer circumferential surface of the coupling unit 200. Furthermore, the rotor and the coupling unit can be connected simultaneously, having one or more strut structures, to form a structure in which a recess or hole is formed between the outer circumferential surface of the coupling unit and the inner circumferential surface of the rotor.

[0061] The braking unit 100 may include a rotor 120 having a disc or drum shape and a coating 110 disposed on the surface of the rotor 120, and as shown in the figure. Figure 2 As shown, a coating 110 is preferably formed on the surface of the disc rotor 120.

[0062] The material of the rotor 120 is not particularly limited and can typically be a low-cost material such as an iron-based alloy, aluminum alloy, or ceramic material. Iron-based metals such as cast iron or gray cast iron are preferred. Rotors 120 made of iron-based alloys are advantageous in terms of price competitiveness and are usually manufactured to meet the standards or specifications required for use in braking devices, including the specifications of the run-out and thickness variation (DTV) of the brake body 10.

[0063] Since the braking unit 100 includes a coating 110 disposed on the surface of the rotor 120, the performance of the braking body 10 is significantly affected by the surface characteristics of the coating 110 formed on the surface of the braking unit 100 and the relationship between the materials of the braking unit 100 and the coating 110. Specifically, the performance of the braking device or the degree of dust generation can vary depending on the surface friction coefficient and roughness of the coating 110, and the lifespan of the braking device can vary depending on the thermal conductivity, coefficient of thermal expansion, and bonding strength relationship between the coating 110 and the braking unit 100.

[0064] According to an embodiment of the present invention, the brake body may have different main friction points depending on the structure and shape of the braking device and the braking method, and a brake in which friction occurs between at least some surfaces of the braking unit 100 or a portion of the surface of the braking unit 100 and a portion of the surface of the coupling unit 200 during braking may be included in the brake body of the present invention.

[0065] In the following description, the brake disc of the brake unit 100 that achieves braking by friction will be described, but the invention is not limited thereto. The brake body 10 that has a coating 110 provided on a portion of the surface of the coupling unit 200, or that generates friction on a portion of the surface of the coupling unit 200 during braking, may also be included within the scope of the invention.

[0066] To prevent air lock caused by brake fluid boiling and forming bubbles when the brake fluid temperature rises, the rotor 120 of the brake unit 100 may further include holes or protrusions for cooling between the two sides of the rotor. For example, the rotor 120 may be disc-shaped, and a ventilated (perforated) disc including multiple holes through the two sides of the rotor 120 may be used as the rotor 120.

[0067] The coating 110 provided on the surface of the rotor 120 can improve the surface characteristics of the braking unit 100 of the brake body 10. More specifically, it can increase the surface hardness of the braking unit 100, improve wear resistance, corrosion resistance and brake disc life, and reduce the amount of dust and particulate matter generated during braking by reducing the surface friction coefficient, thus having advantages in terms of dust and particulate matter emission.

[0068] The coating 110 can be formed on one or both sides of the rotor 120 of the braking unit 100. The position and number of the surfaces on the rotor 120 where the coating 110 is provided, as well as the area of ​​the coating 110 provided, can vary depending on the shape of the rotor 120 and the operation method.

[0069] When the rotor 120 is formed as a disc, the coating 110 is preferably disposed on at least one side surface of the disc rotor; when the rotor 120 is formed as a drum, the coating 110 is preferably disposed in at least one region of the inner circumferential surface of the drum rotor.

[0070] This is because, for a brake body 10 with a disc rotor 120, the friction unit 20 of the braking device is preferably disposed on one or both sides of the outer surface of the brake body 10; for a brake body 10 with a drum rotor 120, the friction unit 20 of the braking device is preferably disposed inside the drum rotor 120.

[0071] The thickness of coating 110 can be formed according to the composition and coating conditions of coating 110, but it can be formed to a thickness of 50 μm to 400 μm, preferably 100 μm to 300 μm.

[0072] When the coating 110 is formed thinner than this range, the formation effect of the coating 110 may be insufficient or the lifespan may be shortened. When the coating 110 is formed thicker than this range, there may be a problem of reduced economic efficiency.

[0073] The coating 110 is preferably an amorphous alloy coating 110 comprising an amorphous alloy having an amorphous phase. The amorphous alloy constituting the amorphous alloy coating 110 is preferably an iron-based amorphous alloy containing Fe.

[0074] The composition of the iron-based amorphous alloy is mainly Fe, and includes a first component selected from at least one of Cr, Co and Mo, and a second component selected from at least one of B, C, Si and Nb, wherein, preferably, the second component may be at least two of B, C, Si and Nb.

[0075] More specifically, relative to 100 parts by weight of Fe contained in the alloy, the iron-based alloy contains 30 to 140 parts by weight of the first component, preferably 35 to 100 parts by weight of the first component, and more preferably 40 to 92 parts by weight of the first component.

[0076] Among Cr, Mo and Co, which can be included as the first component, the iron-based alloy preferably has Cr as an essential component as the first component, and contains 18.0 parts by weight or less of Mo relative to 100 parts by weight of Fe, preferably 10.0 parts by weight or less of Mo.

[0077] Furthermore, when the Fe-based alloy contains Cr, the Cr content is more than three times the Mo content, preferably more than four times the Mo content, including cases where Mo is not included in the first component.

[0078] In iron-based alloys, when the content of Mo meets the corresponding weight range and when the content of Cr and Mo meets the aforementioned ratio, the amorphous formation ability of the iron-based alloy will be improved, and an alloy coating 110 mainly comprising an amorphous phase can be formed, thus improving the wear resistance of the coating 110.

[0079] The iron-based alloy contains 4 to 20 parts by weight of a second component relative to 100 parts by weight of Fe, preferably 5 to 19 parts by weight of the second component.

[0080] In this case, the iron-based alloy may contain at least two of B, C, Si, and Nb as a second component, preferably containing either Si or Nb, or both Si and Nb as a second component. That is, it may include Si and / or Nb. When the iron-based alloy contains either Si or Nb, or both Si and Nb as a second component, the content of Si or Nb is 9 parts by weight or less, preferably 1.5 parts by weight to 8.0 parts by weight, and more preferably 2.0 parts by weight to 6.0 parts by weight.

[0081] When an iron-based alloy contains Si or Nb, or both Si and Nb as a second component and Si or Nb respectively meets the aforementioned weight range, the amorphous phase forming ability of the iron-based alloy will be improved and an alloy coating 110 mainly comprising an amorphous phase can be formed, thereby having the beneficial effect of improving the wear resistance of the coating.

[0082] Furthermore, the present invention may also include a third component, which may be at least one selected from W, Y, Mn, Al, Zr, Ni, Sc and P.

[0083] In this case, the total amount of the added third component relative to 100 parts by weight of Fe is less than 1.125 parts by weight, preferably less than 1.0 parts by weight, and more preferably less than 0.083 parts by weight.

[0084] Furthermore, the third component contains 0.9 parts by weight or less, preferably 0.05 parts by weight or less, relative to 100 parts by weight of Fe. When the content exceeds the corresponding range, the amorphous formation ability may be significantly reduced.

[0085] When an iron-based alloy contains a first component and a second component within a corresponding range, or contains a first component to a third component within a corresponding range and has a composition with excellent amorphous forming ability, the iron-based alloy of the corresponding composition can be used as the amorphous alloy of the present invention. When the weight parts of the first component to the third component exceed the above range, the mechanical properties of the surface may deteriorate or the coefficient of friction may increase due to the decrease in amorphous forming ability.

[0086] As mentioned above, the ability to form amorphous states is determined by the differences in atomic size, packing ratio, deep eutectic, and entropy of each element.

[0087] Iron (Fe), as the main component of the amorphous alloy constituting the amorphous alloy coating 110, can also be included in the constituent materials of the rotor 120 to which the amorphous alloy coating 110 is formed. Specifically, when cast iron or an iron-based alloy containing a high proportion of Fe is used as the material of the rotor 120, since the coefficients of thermal expansion of the rotor 120 and the amorphous alloy coating 110 can have similar values, even if a large temperature change occurs due to friction during the operation of the braking device, the amorphous alloy coating 110 will not peel off from the substrate or be damaged at the interface.

[0088] At this time, the coefficient of thermal expansion (A) of the amorphous alloy including the amorphous alloy coating 110 is similar to the coefficient of thermal expansion (B) of the rotor 120 of the braking unit 100, and their ratio (A / B) is 1.0 to 1.4 times, preferably 1.0 to 1.3 times, and more preferably 1.2 to 1.25 times.

[0089] When the ratio of the coefficients of thermal expansion is less than or greater than the corresponding range, the difference in the coefficients of thermal expansion between the braking unit 100 and the coating 110 will increase. Therefore, under the condition of frequent temperature changes due to frictional heat generated during braking, the bonding force between the substrate and the coating 110 may be weakened or the life of the coating 110 may be shortened.

[0090] Due to the small difference in the coefficient of thermal expansion between the braking unit 100 and the coating 110, the braking body 10 may not require an adhesive layer or intermediate layer between the rotor and the coating when forming the coating 110. Furthermore, even without a heat treatment process when forming the coating 110, the coating 110 with uniform thickness and performance can be directly formed on the surface of the rotor 120 of the braking body 10.

[0091] Due to these characteristics, when the coating 110 is formed on the rotor 120 of the brake body 10, the coating 110 can be formed directly on the brake unit 100 without the need to form an additional adhesive layer or primer layer, thus having the advantages of simplifying the coating process and production process and reducing manufacturing costs.

[0092] On the other hand, braking force may be generated on the surface of the coating 110 during braking. During braking, the rotational kinetic energy of the brake body 10 can be converted into heat energy to provide braking force.

[0093] The surface friction coefficient of coating 110 is 0.001μ to 0.8μ under a load of 100N, preferably 0.001μ to 0.05μ, and 0.06μ to 0.12μ under a load of 1000N, preferably 0.06μ to 0.10μ.

[0094] When the surface friction coefficient of coating 110 is greater than this range, dust may be generated due to friction and heat may increase during braking. When the surface friction coefficient is less than this range, the braking performance of the braking device may deteriorate.

[0095] Furthermore, the surface roughness of the coating 110 may vary depending on the material and properties of the friction unit 20 used in the braking device, such as brake pads; however, the arithmetic mean roughness (Ra) value may be in the range of 0.03 to 0.5, preferably in the range of 0.3 to 0.4.

[0096] If the arithmetic mean roughness (hereinafter referred to as roughness) of coating 110 is below this range, the coefficient of friction of the surface may decrease, or friction may not be generated sufficiently. If the roughness is above the corresponding range, there may be problems with surface wear and increased dust generation.

[0097] When forming a coating 110 made of an iron-based amorphous alloy, the method of forming the coating 110 is not limited, but the coating can be formed by coating method using amorphous alloy powder with a corresponding alloy composition range.

[0098] Furthermore, according to one embodiment of the present invention, the surface of the coating 110 is processed by beading or shot peening, thereby controlling the coefficient of friction or roughness within a suitable range, and improving wear resistance and fatigue toughness by increasing compressive stress.

[0099] When coating 110 is formed by spraying, iron-based amorphous alloy powder can be used. When the alloy powder is prepared by atomization, the content of amorphous alloy powder is very high, preferably 90% or more, more than 95%, 97% or more, 99% or more, or 99.9% or more, practically containing 100% amorphous phase. That is, iron-based amorphous alloy powder with a high proportion of amorphous phase as described above can be prepared by adjusting the cooling rate.

[0100] Alloy materials used for iron-based amorphous alloy coatings can be prepared in various shapes, but are preferably prepared in powder form, and the amorphous alloy powder is preferably a powder with high sphericity.

[0101] The iron-based amorphous alloy powder is preferably prepared using the same composition as the target composition of the coating 110 described above, and alloy powder with the same composition as the alloy component of the coating 110 can also be used. During the preparation of the alloy powder, raw materials of a corresponding weight calculated according to the target composition are added and melted to prepare the composition. At this time, due to the purity of the added raw materials and phenomena such as the vaporization of certain elements during melting, some differences may occur between the target composition and the actual composition. When the target composition or the actual composition includes the alloy component described in this specification, it can be considered as the same composition as the coating 110 of the present invention or the alloy powder of the present invention.

[0102] The iron-based amorphous alloy powder according to embodiments of the present invention has excellent properties such as density, strength, wear resistance, friction resistance and corrosion resistance due to its high proportion of amorphous phase.

[0103] The average particle size of the iron-based amorphous alloy powder prepared according to the embodiments of the present invention can be in the range of 1 μm to 150 μm, but is not limited thereto, and the powder size can be adjusted by sieving according to the application.

[0104] For example, when performing spraying, the size of the target iron-based amorphous alloy powder can be adjusted to the range of 15μm to 45μm through sieving; when performing MIM (powder injection molding), the size of the target iron-based amorphous alloy powder can be adjusted to below 20μm through sieving.

[0105] Even if the iron-based amorphous alloy powder is remelted or exposed to high temperature and then cooled and solidified again, the aforementioned amorphous proportion can be maintained. At this time, the proportion of amorphous material (a) in the iron-based amorphous alloy powder prepared by atomization and the proportion of alloy prepared by melting the iron-based amorphous alloy powder above its melting point and then cooling (b) satisfy the following formula.

[0106] (Equation 1)

[0107] 0.9≤b / a≤1

[0108] In order to derive (b), the method of preparing the alloy by melting the iron-based amorphous alloy powder above the melting point of the alloy and then cooling it can be, for example, traditional casting methods such as spraying, 3D printing, and metallurgy.

[0109] Furthermore, the b / a ratio of Formula 1 is preferably 0.95 to 1, more preferably 0.98 to 1, and even more preferably 0.99 to 1.

[0110] On the other hand, when forming the coating 110, a surface treatment step of the rotor 120 of the brake body 10 can be performed before forming the coating 110, and the surface treatment can smooth the surface of the rotor or make the coating evenly bonded to the rotor.

[0111] As a coating method, any coating method that can be used by those skilled in the art can be used to form an amorphous alloy coating 110 with the same composition and thickness, including spraying or laser cladding. As an example, iron-based amorphous alloy powder can be applied to a spraying process to form an amorphous coating 110 on the rotor 120.

[0112] Spraying is a method of applying heated metal or metal compound to the surface of a workpiece to make it adhere to the workpiece. High-velocity oxygen fuel spraying (HVOF), plasma spraying, laser cladding spraying, general flame plating, diffusion spraying, cold spraying, vacuum plasma spraying (VPS), and low-pressure plasma spraying (LPPS) are all spraying methods.

[0113] The iron-based amorphous alloy powder according to embodiments of the present invention has excellent amorphous formation ability. Even without ensuring a very high cooling rate, it can form an amorphous state. Therefore, even with the coating 110 formed as described above, the proportion of amorphous state in the coating will not decrease.

[0114] That is, the iron-based amorphous alloy powder of the present invention has a high proportion of amorphous phase. When the iron-based amorphous alloy powder of the present invention with an amorphous phase ratio of 90% or more, 99% or more, 99.9% or more, or substantially 100% is used as a spraying material, the coating contains 90% or more, 95% or more, 97% or more, 99% or more, 99.9% or more, or substantially 100% of the amorphous phase, and therefore its physical properties are excellent.

[0115] In particular, when using the alloy powder of the present invention for supersonic flame spraying, the improvement in physical properties can be maximized because the proportion of amorphous state is actually maintained.

[0116] Furthermore, the iron-based amorphous alloy powder of the present invention has a very high coating density of 98% to 99.9% when measured, which can suppress the penetration of corrosion products through pores.

[0117] The alloy powder used for spraying has a particle size of 10μm to 100μm, preferably 15μm to 55μm. When the particle size of the alloy powder is less than 10μm, small particles will adhere to the spraying gun during the spraying process, which may reduce the efficiency of the operation. When the particle size exceeds 100μm, it may cause a decrease in coating productivity and efficiency because it cannot be completely dissolved and will collide with the substrate (i.e., it falls to the floor without forming a coating).

[0118] On the other hand, the Vickers hardness of the coating 110 comprising iron-based amorphous alloy powder in an embodiment of the present invention is 700 Hv. 0.2 ~1200Hv 0.2 Preferably 800Hv 0.2 ~1000Hv 0.2 The coefficient of friction (friction resistance) is 0.001 μm to 0.08 μm under a load of 100 N, preferably below 0.05 μm, and 0.06 μm to 0.12 μm under a load of 1000 N, preferably below 0.10 μm.

[0119] In particular, unlike existing coatings, when coating 110 is formed by supersonic flame spraying, the cross-section has almost no pores, thus having the maximum full density, and even if there are pores, its porosity is only 0.1% to 1.0%.

[0120] When supersonic flame spraying is performed, a multi-path structure is formed on the substrate. Specifically, black oxides are deposited on each layer, and multiple layers are stacked in a wave-like shape. Normally, this would reduce the performance of the coating 110 and make it brittle, but in this invention, because the coating 110 has fewer pores and oxide films, it can exhibit ultra-high density and improve the performance of the coating 110.

[0121] When the coating 110 is formed by spraying, there will be excellent adhesion between the rotor 120 of the braking unit 100 and the coating 110. Therefore, even without additional heat treatment or other processes, a coating 110 with excellent adhesion can be formed.

[0122] According to an embodiment of the present invention, the brake body 10 directly forms an amorphous alloy coating 110 on the surface of the rotor 120 of the brake unit 100 without forming an adhesive layer or intermediate layer. Therefore, no additional process of forming an adhesive layer or intermediate layer is required before the process of forming the coating 110. The brake unit 100 with the coating 110 on the surface of the rotor 120 can be obtained in just one step. Due to these characteristics, it has advantages in terms of productivity and price competitiveness.

[0123] Furthermore, when a coating 110 is formed on the surface of the rotor 120, although the brake body 10 is not shown, it may also include a first coating formed directly on the surface of the rotor 120 and a second coating formed on the surface of the first coating.

[0124] The second coating may be made of an amorphous alloy having the same composition as the first coating, and may include other coatings with different amorphous phase ratios or porosities formed by different coating methods.

[0125] When the proportions of the amorphous phases in the first and second coatings are different, it is preferable that the proportion of the amorphous phase in the second coating exposed to the external environment is higher than that in the first coating. The porosity of the coatings can vary depending on the coating method, but it is preferable to have a small porosity, and more preferably, the porosity of the second coating is less than or equal to that of the first coating.

[0126] Furthermore, the coating 110 of the present invention can be formed on a portion of the surface of the brake body 10. The coating 110 is preferably formed on at least a portion of the surface of the region where the rotor 120 of the brake body 10 contacts the friction unit 20 when it rotates, and can be provided in at least a portion of the region that contacts the friction unit 20, which will be described later.

[0127] For example, when the coating 110 is applied to a portion of the surface of the rotor 120 of the brake body 10, the surface of the brake unit 100 may not be smooth depending on whether the coating 110 is formed or not.

[0128] In order to form the entire surface of the braking unit 100 flat, the rotor 120 can be pre-manufactured in different shapes or patterns during the manufacturing process, such that the area to be coated 110 is more recessed or sunken than the area without coated 110.

[0129] Furthermore, by adjusting the thickness of the coating 110, the surface of the brake body 10 can be made to have unevenness according to the shape of the coating 110.

[0130] When the coating 110 is configured to have a specific pattern on a portion of the surface of the rotor 120, unevenness may appear on the surface, and frictional heat can be effectively dissipated from the surface through these unevennesses, thus the effect of extending the life of the brake body 10 can be expected.

[0131] As an example, a patterned coating 110 can be provided on the surface of the rotor 120, such that the inner and outer peripheral surfaces of the coating 110 form concentric annular regions along the center relative to the rotation axis of the brake body 10, and the patterned coating 110 can be provided as one or more non-connected regions.

[0132] As another example of the pattern of coating 110, the pattern formed along the radial direction from the rotation axis of brake body 10 can be repeated multiple times to form a rotationally symmetrical shape. In this case, the shape of each pattern is not limited, but it is preferred to be the same shape, the spacing between each pattern is preferably the same, and it can be a spiral shape radiating in a radial direction or a helical shape.

[0133] When the coating 110 is formed on a portion of the surface of the rotor 120, friction may occur simultaneously in the area where the coating 110 is formed and the area where the coating 110 is not formed relative to the rotating brake body 10. Furthermore, due to the thickness of the coating 110 and the surface structure of the rotor 120 of the brake body 10, it can form unevenness or increase the surface roughness. Therefore, a variety of rotor 120 and coating 110 patterns with different structures can be used. Detailed Implementation

[0135] Another aspect of the present invention provides a braking device for braking drive machinery, including a drive shaft, and the braking device includes the aforementioned brake body 10. For example... Figure 1 As shown, the braking device includes a braking body 10 and a friction unit 20.

[0136] During braking, the friction unit 20 receives braking force or a signal and moves toward the brake body 10. At this time, the displacement of the friction unit 20 causes the surface of the brake unit 100 of the rotating brake body 10 to come into contact with and rub against the friction unit 20, thereby generating frictional force to provide braking force for the driven machinery.

[0137] The braking device may include one or more friction units 20, and the friction units 20 may contact one or both sides of the braking body 10. For example, a friction unit 20 may be provided on each of the two sides of the braking body 10, and may be simultaneously moved in the direction of the braking body 10 to contact the braking unit 100 of the braking body 10.

[0138] The friction unit 20 rubs against at least one surface of the braking unit 100 of the braking body 10 by displacement. At this time, the rotational kinetic energy of the braking body 10 is converted into heat energy through friction and braking is achieved.

[0139] The shape, structure and number of friction units 20 can vary depending on the type and shape of the braking device. For example, a disc brake can use one or more brake pads as friction units 20.

[0140] At this point, the brake pads can be engaged with a pair of backplates that can slide, and these brake pads can face each other and be positioned between them.

[0141] The material of brake pads is not restricted and can be organic, non-steel, low steel, steel-based, ceramic, resin, or semi-metallic materials that do not use asbestos-based materials.

[0142] The braking device includes not only the brake body 10 and the friction unit 20, but also other components. However, the description of components other than the brake body 10 and the friction unit 20 is omitted in this specification, and the components of a general braking system that can be inferred from the level of ordinary technology may be included in the braking device in this respect.

[0143] Example

[0144] Examples 1 to 8: Preparation of brake bodies using iron-based amorphous alloy powder

[0145] The components and weight ratios shown in Table 1 were supplied to an atomizer under a nitrogen atmosphere, atomized into a molten state, and then cooled according to the cooling rates shown in Table 1 to prepare the amorphous alloy powders shown in Examples 1 to 8.

[0146] Next, using the iron-based amorphous alloy powder and equipment (Oerlikon Metco Diamond Jet series HVOF gas spraying system) from Examples 1 to 8, and with oxygen and propane as fuel, a 0.3 mm thick coating 110 was formed on the surface of the cast iron brake disc using a high-velocity oxygen fuel (HVOF) process at a spray distance of 30 cm. The equipment and specific conditions used at this time are as follows.

[0147] DJ Gun HVOF

[0148] [Conditions] Gun type: Mixed, Air cap: 2701, LPG flow: 160 SCFH, LPG pressure: 90 PSI, Oxygen flow: 550 SCFH, Oxygen pressure: 150 PSI, Air flow: 900 SCFH, Air pressure: 100 PSI, Nitrogen flow: 28 SCFH, Nitrogen pressure: 150 PSI, Spray gun speed: 100 m / min, Spray gun spacing: 3.0 mm, Feeder rate: 45 g / min, Ground clearance: 250 mm

[0149] Table 1

[0150]

[0151] *D50 (unit: μm)

[0152] Comparative example

[0153] Comparative Examples 1 to 7: Preparation of brake bodies using iron-based alloy powder

[0154] The components and weight ratios shown in Table 2 were supplied to an atomizer under a nitrogen atmosphere, atomized into a molten state, and then cooled at the cooling rate shown in Table 2 to prepare the amorphous alloy powders shown in Comparative Examples 1 to 7.

[0155] Next, coating 110 was formed using the prepared alloy powder in the same manner as in the examples. The results showed that the prepared coating 110 contained both amorphous and crystalline phases, or was mostly crystalline phase.

[0156] Table 2

[0157]

[0158] *D50 (unit: μm)

[0159] Experimental Example

[0160] Experimental Example 1: Evaluation of Coating Hardness

[0161] Microhardness tests were performed on the cross-sections of the coating samples from Examples 3, 4, 6, 7, 8 and Comparative Examples 1 to 4 using an HVS-10 digital low load Vickers Hardness Tester Machine. The results are shown in Table 3 below.

[0162] Table 3

[0163] distinguish area <![CDATA[Test value)HV 0.2 > <![CDATA[Average HV 0.2 > Example 3 section 802 / 754 / 828 / 765 / 710 771 Example 4 section 898 / 834 / 944 / 848 / 789 862 Example 6 section 1304 / 1139 / 1097 / 1194 / 1139 1174 Example 7 section 892 / 788 / 811 / 828 / 843 832 Example 8 section 910 / 899 / 869 / 937 / 922 907 Comparative Example 1 section 669 / 756 / 623 / 689 / 683 684 Comparative Example 2 section 928 / 862 / 876 / 921 / 802 877 Comparative Example 3 section 828 / 848 / 1012 / 944 / 771 880 Comparative Example 4 section 821 / 855 / 808 / 783 / 633 780

[0164] As shown in Table 3, the sample with the alloy powder of Example 6 applied had the best cross-sectional average hardness, while the other examples showed hardness values ​​similar to the comparative examples.

[0165] Experimental Example 2: Evaluation of the coefficient of thermal expansion of the coating and braking unit

[0166] Amorphous alloy samples with the same composition as those in Examples 6 to 8 and Comparative Examples 1 to 3 were prepared, and the coefficient of thermal expansion was measured. The coefficient of thermal expansion of the coating and the braking unit was compared with that of commonly used cast iron as the reference material. The coefficient of thermal expansion of cast iron was 10.2 ppm / ℃.

[0167]

Table 4

[0168]

[0169] Experimental Example 3: Evaluation of the friction and wear resistance of coatings using alloy powder

[0170] To evaluate the frictional force (coefficient of friction), the wear width of coatings with the same alloy composition as those in Examples 1, 4, 5, 7, 8 and Comparative Examples 1 to 3 was obtained by ring-lump testing under lubrication conditions. Specifically, the ring-lump test was conducted using an L-MM46 MR-H3A high-speed ring-lump wear machine with hydromantic lubricating oil, and the test parameters were performed in the order of 50 N·5 min → 100 N·25 min → 1000 N·55 min.

[0171] The obtained friction coefficients and wear widths are shown in Tables 5 and 6 below.

[0172]

Table 5

[0173]

[0174]

Table 6

[0175] distinguish Width / mm Example 1 0.79 Example 4 0.75 Example 5 0.71 Example 7 0.68 Example 8 0.68 Comparative Example 1 0.98 Comparative Example 2 1.15 Comparative Example 3 0.82

[0176] Experimental Example 4: Evaluation of the Corrosion Resistance of the Coating

[0177] Figure 3 The images are uncorroded / corroded cross sections of the sprayed coating samples of iron-based amorphous alloy powders from Examples 2, 5, and 7 of this invention, observed using an optical microscope. (a) to (c) are images of the samples from Examples 2, 5, and 7, respectively. Figure 4 The images are uncorroded / corroded cross sections of the sprayed coating samples using alloy powders from Comparative Examples 5, 6, and 7, observed using an optical microscope. (a) to (c) are images of the samples from Comparative Examples 5, 6, and 7, respectively.

[0178] Specifically, each sprayed coating sample was immersed in a 95% to 98% sulfuric acid (H2SO4) solution at room temperature for 5 minutes. After immersion, the cross-sections and surfaces of the uncorroded and corroded coating samples were observed using an optical microscope (Leica DM4 M). Figure 3 and Figure 4 In the diagram, the left side represents non-corrosive materials, and the right side represents corroded materials.

[0179] The observation results show that when using the coating samples of Examples 2, 5, and 7, as Figure 3 As shown, there was no significant difference in appearance before and after immersion in sulfuric acid, indicating that it has the best corrosion resistance.

[0180] In contrast, when using the coating samples of Comparative Examples 5, 6, and 7, such as Figure 4 As shown, the corrosion is severe, indicating extremely poor corrosion resistance.

[0181] This is determined by whether the coating is amorphous. In the examples, the coating did not react at all with strong acid corrosives, while in the comparative examples containing crystals, the coating reacted with the corrosives and was corroded, thus showing poor corrosion resistance.

[0182] The features, structures, effects, etc., shown in the above embodiments can be combined or modified by those skilled in the art to which these embodiments pertain. Therefore, the content related to these combinations and modifications should be understood to be included within the scope of this invention.

[0183] Explanation of reference numerals in the attached figures

[0184] 10: Braking unit; 20: Friction unit

[0185] 100: Braking unit; 110: Coating

[0186] 120: Rotor; 200: Connecting unit

Claims

1. A braking body, disposed on a braking device, the braking body comprising: A coupling unit is connected to the drive shaft; as well as A braking unit having a rotor connected to the outer peripheral surface of the connecting unit and a coating formed on the surface of the rotor. The coating comprises an amorphous alloy, and the coefficient of thermal expansion of the coating is 1.0 to 1.4 times that of the rotor. The amorphous alloy comprises: Fe; The first component, wherein the first component is at least one selected from Cr, Mo, and Co; and The second component is at least one selected from B, C, Si, and Nb. The amorphous alloy comprises, relative to 100 parts by weight of Fe, 30 to 140 parts by weight of the first component and 4 to 20 parts by weight of the second component.

2. The braking body according to claim 1, wherein, The rotor contains an iron-based alloy.

3. The braking body according to claim 1, wherein, The average coefficient of friction of the coating measured under 100N conditions is 0.001 to 0.

08.

4. The braking body according to claim 1, wherein, The Vickers hardness of the coating is 700Hv to 1200Hv.

5. The braking body according to claim 1, wherein, The coating has a porosity of 0.1% to 1.0%.

6. The braking body according to claim 1, wherein, The thickness of the coating is 50μm to 400μm.

7. The braking body according to claim 2, wherein, The coating is formed by spraying iron-based amorphous alloy powder onto the rotor surface.

8. The braking body according to any one of claims 1 to 7, wherein, The rotor is disc-shaped, and the coating is formed on at least one side surface of the disc.

9. The braking body according to any one of claims 1 to 7, wherein, The rotor is drum-shaped, and the coating is formed on the inner circumferential surface of the rotor.

10. A braking device for braking a drive mechanism including a drive shaft, the braking device comprising: A braking body, comprising a coupling unit and a braking unit, wherein the coupling unit engages with and rotates with the drive shaft during driving, and the braking unit is connected to the outer peripheral surface of the coupling unit; as well as A friction unit that, during braking, displaces towards the braking body to contact the braking body and generates friction with it. The braking unit includes a rotor connected to the coupling unit and a coating formed on the surface of the rotor. The coefficient of thermal expansion of the coating is 1.0 to 1.4 times that of the rotor, and the coating comprises an amorphous alloy. The amorphous alloy comprises: Fe; The first component, wherein the first component is at least one selected from Cr, Mo, and Co; and The second component is at least one selected from B, C, Si, and Nb. The amorphous alloy comprises, relative to 100 parts by weight of Fe, 30 to 140 parts by weight of the first component and 4 to 20 parts by weight of the second component.

11. The braking device according to claim 10, wherein, The rotor contains an iron-based alloy.

12. The braking device according to claim 10 or 11, wherein, The rotor is disc-shaped, and the coating is formed on at least one side surface of the rotor.

13. The braking device according to claim 10 or 11, wherein, The rotor is drum-shaped, and the coating is formed on the inner circumferential surface of the rotor.

Images