Grinding wheel for grinding

Abstract

The present invention provides a grinding wheel for grinding, comprising: a wheel center portion containing steel; and a wheel outer peripheral portion disposed on the outer surface of the wheel center portion and configured such that fiber reinforced plastic (FRP) layers are laminated and bonded in multiple layers in a direction perpendicular to the outer surface of the wheel center portion, wherein the fiber reinforced plastic (FRP) layers have at least one woven pattern layer selected from woven fabric layers and unidirectional fabric layers.

Description

Technical Field

[0001] This invention relates to a grinding wheel for grinding. Background Technology

[0002] Typically, concrete, asphalt, various blocks and refractory materials, as well as stone such as marble, require a secondary finishing process after the initial processing. This finishing involves smoothing the surface by removing any remaining small protrusions or scratches. Grinding wheels are primarily used for this purpose. This is especially true when machining crankshafts, including pins or journals, where fine machining is required and consistent surface roughness and quality are essential; therefore, grinding wheels are necessary.

[0003] However, the grinding wheels used for crank machining are made of steel and are quite heavy. Therefore, the problem is that a crane or forklift is required to change the grinding wheel, which increases the change time. Furthermore, the use of steel grinding wheels can cause the material surface of the pin or journal to crack and fatigue due to burning.

[0004] Therefore, it is necessary to develop a grinding wheel that can reduce tool wear, thereby reducing tool costs and improving manufacturing efficiency and productivity. Summary of the Invention

[0005] Therefore, the present invention was made in view of the problems encountered in the related art, and its specific objectives are as follows.

[0006] The present invention aims to provide a grinding wheel, comprising: a wheel center portion containing steel; and a wheel outer peripheral portion disposed on the outer surface of the wheel center portion and configured such that fiber reinforced plastic (FRP) layers are laminated and bonded in multiple layers in a direction perpendicular to the outer surface of the wheel center portion, wherein the fiber reinforced plastic (FRP) layers have at least one woven pattern layer selected from woven fabric layers and unidirectional fabric layers, and the woven pattern layer is laminated with a predetermined thickness range and a predetermined lamination direction.

[0007] The purpose of this invention is not limited to the above-described purpose, as can be clearly understood from the following description, and is achieved by the means and combinations thereof as set forth in the claims.

[0008] In one aspect, the present invention provides a grinding wheel comprising: a wheel center portion containing steel; and a wheel outer periphery portion disposed on the outer surface of the wheel center portion and configured such that fiber reinforced plastic (FRP) layers are laminated and bonded in a multilayer manner in a direction perpendicular to the outer surface of the wheel center portion, wherein the fiber reinforced plastic (FRP) layers have at least one woven pattern layer selected from woven fabric layers and unidirectional fabric layers.

[0009] The fiber-reinforced plastic layer includes at least one selected from the group consisting of carbon fiber reinforced plastic (CFRP), glass fiber reinforced plastic (GFRP), and aramid fiber reinforced plastic (AFRP).

[0010] The fiber bundles of the fiber-reinforced plastic (FRP) layer consist of 1k to 24k strands of yarn per layer.

[0011] The outer periphery of the wheel is configured such that a core portion located at the center of the outer periphery of the wheel, a middle portion located at at least one side of the core portion, and a surface portion located on the middle portion are laminated and joined together.

[0012] Each of the core and the surface comprises a multi-layered woven fabric.

[0013] The core layer has a thickness of 8 to 12 layers.

[0014] The surface layer has a thickness of 22 to 28 layers.

[0015] The woven fabric layer is a woven fabric layer interwoven in the 0° and 90° directions.

[0016] The woven fabric layer can be woven in a plain weave.

[0017] The middle section includes multiple unidirectional fabric layers.

[0018] The thickness of the unidirectional fabric layer is 90 to 100 layers.

[0019] Unidirectional fabric layers are laminated at cross angles of 85° to 95° to form multiple layers.

[0020] The grinding wheel further includes a grinding section disposed on the outer surface of the outer periphery of the wheel and comprising abrasive material.

[0021] According to the present invention, the grinding wheel is constructed such that the position and thickness of the fiber-reinforced plastic (FRP) layer on the outer periphery of the wheel, located on the outer surface of the wheel center, vary according to the type of woven pattern layer. Therefore, compared to conventional grinding wheels, it exhibits superior mechanical properties and vibration / shock absorption and mitigation effects. Consequently, it not only avoids problems such as cracks and fatigue failure caused by combustion, but also improves the quality and productivity of processed products, and is lighter than conventional grinding wheels. Unlike conventional grinding wheels, when the grinding part is completely consumed, a new grinding part can be replaced via its detachable attachment, allowing the outer periphery (wheel body) to be continuously reused, reducing replacement time and tool wear.

[0022] The effects of the present invention are not limited to those described above, and should be understood to include all effects that can be reasonably expected from the following description. Attached Figure Description

[0023] The above and other features of the invention will now be described in detail with reference to certain exemplary embodiments illustrated in the accompanying drawings, which are given hereinafter by way of illustration only and are not intended to limit the invention, wherein:

[0024] Figure 1 This is a perspective view of the grinding wheel of the present invention; and

[0025] Figure 2 This is a cross-sectional view showing the interior of the grinding wheel of the present invention. Detailed Implementation

[0026] The above and other objects, features, and advantages of the present invention will become clearer from the following preferred embodiments and in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed herein, and the invention can be modified into different forms. These embodiments are provided to thoroughly explain the invention and to fully convey the spirit of the invention to those skilled in the art.

[0027] Throughout the accompanying drawings, the same reference numerals will refer to the same or similar elements. For clarity of the invention, the dimensions of the structures are depicted as larger than their actual dimensions.

[0028] It will be further understood that, when used in this specification, terms such as “comprising,” “including,” “having,” etc., refer to the presence of the stated features, integers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. Furthermore, it should be understood that when an element such as a layer, film, region, or sheet is referred to as being “above” another element, it may be directly above the other element, or there may be intermediate elements between them. Similarly, when an element such as a layer, film, region, or sheet is referred to as being “below” another element, it may be directly below the other element, or there may be intermediate elements between them.

[0029] Unless otherwise stated, all figures, values, and / or representations used herein to indicate the amounts of components, reaction conditions, polymer compositions, and mixtures are to be considered approximations that include the various uncertainties inherent in the measurement that influence the determination of these values, and are therefore to be understood in all cases to be modified by the term "about". Furthermore, when numerical ranges are disclosed in this specification, unless otherwise stated, the range is continuous and includes all values ​​from the minimum to the maximum of the range. Additionally, when such ranges involve integer values, all integers from the minimum to the maximum are included, unless otherwise stated.

[0030] In this specification, when describing the range of a variable, it should be understood that the variable includes all values ​​described within the range, including endpoints. For example, the range "5 to 10" should be understood to include any subranges, such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc., and individual values ​​of 5, 6, 7, 8, 9, and 10, and should also be understood to include any values ​​between valid integers within the range, such as 5.5, 6.5, 7.5, 5.5 to 8.5, 6.5 to 9, etc. Similarly, the range "10% to 30%" should be understood to include subranges, such as 10% to 15%, 12% to 18%, 20% to 30%, etc., and all integers including values ​​up to 30% such as 10%, 11%, 12%, 13%, etc., and should also be understood to include any values ​​between valid integers within the range, such as 10.5%, 15.5%, 25.5%, etc.

[0031] Traditional grinding wheels are made of steel and are heavy. Therefore, the problems are that a crane or forklift is needed to replace the grinding wheel, which increases the replacement time. In addition, the use of steel grinding wheels has the problem that the material surface of the pins or journals may crack and fatigue due to burning.

[0032] Therefore, the inventors conducted in-depth research to solve the above-mentioned problems and thus determined a grinding wheel that is manufactured to include a wheel center portion made of metal (steel) and a grinding wheel outer periphery portion located on the outer surface of the wheel center portion. The position and thickness of the fiber reinforced plastic (FRP) layer are configured to vary according to the type of woven pattern layer. Compared with existing grinding wheels, it can exhibit excellent vibration / shock absorption and cancellation effects, and therefore will not cause problems such as cracking and fatigue failure due to combustion. Moreover, it can improve the quality and productivity of processed products. Furthermore, unlike existing grinding wheels, when the grinding part is completely consumed, a new grinding part can be detachably attached and replaced, thereby reducing replacement time and tool wear, thus achieving the purpose of the present invention.

[0033] Figure 1 This is a perspective view showing the grinding wheel 1 according to the present invention. (Refer to...) Figure 1 The grinding wheel includes: a steel-containing wheel center portion 10; a wheel outer peripheral portion 20 disposed on the outer surface of the wheel center portion and configured such that fiber reinforced plastic (FRP) layers are laminated and bonded in multiple layers in a direction perpendicular to the outer surface of the wheel center portion; and a grinding portion 30 disposed on the outer surface of the wheel outer peripheral portion and including abrasive material.

[0034] A fiber-reinforced plastic (FRP) layer is a layer containing fiber-reinforced plastic (FRP), a composite material in which fibers are molded using a matrix such as epoxy resin or polyamide. The types of fiber-reinforced plastic (FRP) can vary depending on the type of fibers used.

[0035] Specifically, depending on the type of fiber used, the fiber reinforced plastic (FRP) layer may include at least one selected from the group consisting of carbon fiber reinforced plastic (CFRP), glass fiber reinforced plastic (GFRP) and aramid fiber reinforced plastic (AFRP), and not only a specific type. Preferably, it may include carbon fiber reinforced plastic (CFRP), which is lightweight and has high strength and high damping effect compared with existing materials and does not require molds.

[0036] Carbon fiber reinforced plastic (CFRP) is a composite material made from carbon fibers using a molding process with a matrix such as epoxy resin or polyamide. It weighs about 20% of the weight of iron and has excellent stiffness, so it can be used in a variety of end applications that require lightweight and high strength, such as high-tech aircraft or warships, as well as various building structural materials.

[0037] Depending on the weave pattern, the fiber-reinforced plastic (FRP) layer may have at least one weave pattern layer selected from woven fabric layers and unidirectional fabric layers. Furthermore, the fiber bundles of the fiber-reinforced plastic layer may consist of 1k to 24k strands of yarn per layer, preferably 3k or 24k strands per layer. Outside of these ranges, if the number of strands is too small, the economic feasibility will decrease due to the increased slitting process for separating the fiber bundles; conversely, if the number of strands is too large, the fiber bundles will become too large, potentially leading to gaps such as air bubbles between the fiber bundles, which may result in poor dimensional stability.

[0038] Specifically, the outer periphery of the grinding wheel according to the invention is configured such that fiber reinforced plastic (FRP) layers are laminated and bonded in a multi-layer manner to replace steel, thereby reducing the overall weight of the grinding wheel, and the wheel center and the outer periphery can be detachably attached, thus reducing replacement time.

[0039] Figure 2 This is a cross-sectional view showing the interior of the grinding wheel 1 according to the present invention. (Refer to...) Figure 2 The wheel center portion 10 may be located at the center of the wheel, the wheel outer peripheral portion 20 may be located on the outer surface of the wheel center portion 10, and may be configured such that fiber reinforced plastic (FRP) layers are laminated and bonded in multiple layers in a direction perpendicular to the outer surface of the wheel center portion, and the abrasive portion 30 may be located on the outer surface of the wheel outer peripheral portion and includes abrasive material.

[0040] The wheel center portion 10 is located at the center of the grinding wheel, is made of steel, and is not particularly restricted, as long as it is detachably attached to the outer periphery portion 20 of the wheel.

[0041] The steel contained in the center part 10 of the wheel can be an alloy made by mixing iron and carbon.

[0042] The wheel center may also include a bushing for securing the grinding wheel 1, including the bushing, to the grinding equipment (not shown) and for compensating for the weak structure of the internal shear stress of the grinding wheel (stress generated by the main cutting force and radial force in the cutting force), and preferably also includes a bushing that can be separated from the grinding wheel for replacement in the event of internal deformation.

[0043] The bushing may have circular holes drilled at predetermined intervals in its surface. The holes may be clamping holes for balancing the grinding wheel, and are preferably used to protect the portion of the bolt connected to the clamp by inserting a metal insert (spiral insert) during balancing of the grinding wheel, so as to protect the threaded portion of the bolt.

[0044] The outer peripheral portion 20 of the wheel may be a composite layer disposed on the outer surface of the wheel center portion 10, and is configured such that fiber reinforced plastic (FRP) layers are laminated and bonded in multiple layers in a direction perpendicular to the outer surface of the wheel center portion, and may constitute the majority of the wheel body of the grinding wheel of the present invention.

[0045] Specifically, the outer periphery 20 of the wheel can be a composite layer in which a core 21, which is parallel to a line perpendicular to the outer surface of the wheel center and located at the center of the outer periphery, an intermediate portion 22, which is parallel to the core and located on at least one side of the core, and a surface portion 23 located on the intermediate portion are laminated and bonded together.

[0046] The core 21 may be parallel to a line perpendicular to the outer surface of the wheel center and may be located at the center of the outer periphery of the wheel, and is preferably a multi-layer structure including fiber reinforced plastic (FRP) layers, especially having multiple layers of woven fabric.

[0047] The woven fabric layer can be a woven fabric layer interlaced in the 0° and 30° direction, the 0° and 45° direction, the 0° and 60° direction, or the 0° and 90° direction, and is not limited to a woven fabric layer interlaced only in a specific direction, but is preferably a woven fabric layer interlaced in the 0° and 90° direction that can be laminated (prepreg compression molding, PCM or autoclave).

[0048] Preferably, the woven fabric layers are interwoven in the 0° and 90° directions, and are woven in plain weave, twill weave, etc., according to the weaving pattern, but not limited to only specific patterns, and are preferably woven in plain weave, which is beneficial to dimensional stability.

[0049] The layer thickness of the core 21 can be determined based on the specific thickness of each layer and the number of layers with a specific thickness in each layer. Specifically, each layer can be 0.1 mm to 0.3 mm, preferably 0.2 mm to 0.26 mm, and more preferably 0.23 mm to 0.25 mm. Therefore, depending on the thickness of a single layer, the core layer thickness can be 1 to 20 layers, preferably 8 to 12 layers, and more preferably 9 to 11 layers.

[0050] The middle portion 22 may be parallel to the core portion and may be located on at least one side of the core portion, preferably on both sides of the core portion.

[0051] The middle layer can be a multi-layered structure, including fiber-reinforced plastic (FRP) layers, and in particular, multi-layered unidirectional fabric layers.

[0052] A unidirectional fabric layer can be a layer in which the fibers are not interwoven but are arranged in one direction and parallel to each other in one direction.

[0053] The unidirectional fabric layer structure can be configured such that the direction of the fibers contained in the first unidirectional fabric layer intersects with the direction of the fibers contained in the second unidirectional fabric layer laminated on the first unidirectional fabric layer at an angle to form multiple layers. Specifically, the angle can be 0° to 180°, and is not limited to a specific value when forming multiple layers. Preferably, the angle is 85° to 95°, more preferably 87° to 93°, and even more preferably 89° to 91°. Since multiple layers are formed by laminating unidirectional fabric layers within the range of the angle, it has advantages such as superior physical properties and low cost compared to using woven fabrics.

[0054] Similar to the core layer thickness, the layer thickness of the intermediate portion 22 can be determined based on the specific thickness of each layer and the number of layers with that specific thickness. Specifically, each layer can be 0.1 mm to 0.3 mm, preferably 0.2 mm to 0.26 mm, and more preferably 0.23 mm to 0.25 mm. Therefore, depending on the thickness of a single layer, the layer thickness of the intermediate portion can be 90 to 100 layers, preferably 93 to 98 layers, and more preferably 94 to 97 layers. Outside of the above range, if the layer thickness of the intermediate portion is too high, the molding cycle will increase, and therefore the manufacturing cost will also increase.

[0055] The surface portion 23 may be located on the middle portion, preferably on each side of the middle portion.

[0056] The surface portion can be a multi-layered structure, including fiber-reinforced plastic (FRP) layers, particularly multi-layered woven fabric layers.

[0057] The weaving direction and weaving pattern of the woven fabric layer contained in the surface part can be the same as those described for the core part.

[0058] Similar to the layer thickness of the core, the layer thickness of the surface portion 23 can be determined based on the specific thickness of each layer and the number of layers with that specific thickness. Specifically, each layer can be 0.1 mm to 0.3 mm, preferably 0.2 mm to 0.26 mm, and more preferably 0.23 mm to 0.25 mm. Therefore, depending on the thickness of a single layer, the layer thickness of the surface portion can be 22 to 28 layers, preferably 24 to 26 layers.

[0059] Specifically, in the grinding wheel according to the present invention, as described above, the fiber-reinforced plastic (FRP) layer in the outer peripheral portion of the outer surface of the wheel center is disposed at different positions and thicknesses according to the weaving pattern described above, thus appropriately positioning the core, middle portion, and surface portion. Therefore, compared with existing grinding wheels, the vibration / shock absorption and cancellation effect can be improved, problems such as cracks and fatigue failure caused by combustion will not occur, and the quality and productivity of processed products can be improved.

[0060] The grinding part 30 is located on the outer surface of the outer periphery of the wheel and has a predetermined thickness. Preferably, the grinding part is positioned on the outer surface of the outer periphery of the wheel between the grinding part and the outer periphery of the wheel by using an adhesive.

[0061] The thickness of the grinding section can be 3T to 5.5T, preferably 3T to 5T, more preferably 1.5T to 2.5T, and even more preferably 1.9T to 2.1T. Outside of the above range, if the thickness is too large, damage may occur.

[0062] The grinding section may include abrasive materials, which may include at least one selected from conventional abrasive materials that can be used in this invention, such as CBN (cubic boron nitride), molten alumina and silicon carbide, and are not limited to containing only specific components, but preferably include CBN (cubic boron nitride) which has excellent high-temperature hardness, high wear resistance and high cutting speed and thus excellent machinability.

[0063] The abrasive particle size can be 110 to 130 mesh, preferably 115 to 125 mesh. Outside of these ranges, if the particle size is too small, the roughness may be very high. On the other hand, if the particle size is too large, the desired roughness can be obtained, but it may result in poor machinability.

[0064] Abrasive concentration refers to the amount of abrasive material contained within the product, specifically the volume percentage of abrasive particles (CBN). For example, a product containing 50 vol% abrasive material is expressed as concentration 200, and the concentration coefficient could be 8.8 Ct / cm³. -3Examples of abrasives may include concentrations of 175 (abrasive volume: 43.75, concentration coefficient: 7.7), 125 (abrasive volume: 37.5, concentration coefficient: 6.6), 100 (abrasive volume: 25, concentration coefficient: 4.4), 75 (abrasive volume: 18.75, concentration coefficient: 3.3), and 50 (abrasive volume: 12.5, concentration coefficient: 2.2). Here, the concentration of the abrasive can be between 150 and 250, preferably between 190 and 210. Outside of these ranges, if the concentration is too low, quality problems may occur, while if the concentration is too high, processability problems may occur.

[0065] The grinding wheel of the present invention that satisfies the above structure is a grinding wheel capable of grinding the pins / journals of a crank. It can be manufactured into any structure according to the specifications of the grinding wheel. The wheel size can be 750 to 430D and 10T to 100T, and the wheel thickness in contact with the machining surface can be 30U to 10U.

[0066] The grinding part in the grinding wheel according to the present invention satisfies the above-mentioned characteristics, which not only mainly prevents damage to the grinding wheel, but also shortens the replacement time by simply replacing it with a detachable accessory when the grinding part is damaged.

[0067] The present invention can be better understood through the following embodiments. These embodiments are illustrated only for the purpose of explaining the present invention and should not be construed as limiting the scope of the invention.

[0068] Example - Abrasive wheel with a woven pattern layer (plain weave)

[0069] To manufacture grinding wheels with a woven pattern layer, a high-temperature, high-pressure autoclave curing process was performed. Specifically, this involved curing at 80°C for 180 minutes and then at 125°C with a pressure of 3.3 kgf / cm². 2 Grinding wheels with the following specifications (wheel size: 650D-50T-5.5X-17U) are manufactured by curing under pressure for 180 minutes.

[0070] Specifically, the wheel center includes a separable / replaceable bearing made of steel containing S45C.

[0071] In addition, a wheel outer perimeter is provided on the outer surface of the wheel center portion. Specifically, the wheel outer perimeter portion is constructed such that a core portion located at the center of the wheel outer perimeter portion and parallel to a line perpendicular to the outer surface of the wheel center portion, a middle portion located on both sides of the core portion and parallel to the core portion, and a surface portion located on the middle portion are laminated and joined together.

[0072] All fiber-reinforced plastic (FRP) layers are carbon fiber reinforced plastic (CFRP) layers, and each layer's fiber bundle consists of 3k strands of yarn per layer.

[0073] The core has a multi-layered structure, including fiber-reinforced plastic (FRP) layers, and particularly multi-layered woven fabric layers. Specifically, the woven fabric layers employ a plain weave structure interwoven in 0° and 90° directions (WSN3KP 200YS FAW (fiber area weight) - 200g / m²). 2 , RC (resin content) - 40%, its layer thickness is 10 layers (1 layer: 0.244mm, 3K).

[0074] The middle section is a multi-layered structure, including fiber-reinforced plastic (FRP) layers, particularly multiple layers of unidirectional fabric. Specifically, the unidirectional fabric layers are arranged at a 90° cross angle (UD→USN300A, FAW-300g / m²). 2 (RC-36%) is laminated with a layer thickness of 95 layers (1 layer: 0.244 mm, 3K).

[0075] The surface layer has a multi-layered structure, including fiber-reinforced plastic (FRP) layers, and particularly multi-layered woven fabric layers. Specifically, the woven fabric layers employ a plain weave structure interwoven in 0° and 90° directions (WSN3KP 200YS FAW-200g / m²). 2 , RC-40%), with a layer thickness of 25 layers (1 layer: 0.244mm, 3K).

[0076] The grinding section is arranged on the outer surface of the outer periphery of the wheel with a thickness of 2T using an adhesive. The abrasive contained in the grinding section is CBN (cubic boron nitride), with a particle size of 120 mesh and a concentration of 200.

[0077] Comparative Example 1 - Grinding wheel with a woven pattern layer (twill)

[0078] The grinding wheel is manufactured in the same manner as in Example 1, except that the woven fabric layers contained in the core and surface portions of the outer periphery of the wheel are woven in a twill weave interwoven in the 0° and 90° directions.

[0079] Comparative Example 2 - Grinding wheel with only one layer of woven pattern

[0080] The grinding wheel was manufactured in the same manner as in Example 1, except that the entire structure of the outer periphery of the wheel was made of a woven fabric layer with a twill weave interwoven in the 0° and 90° directions.

[0081] Comparative Example 3 – Grinding Wheel Containing Aluminum

[0082] Unlike Example 1, a grinding wheel containing aluminum (6061T4) was prepared, wherein the central part of the wheel and the outer periphery of the wheel are integrated.

[0083] Comparative Example 4 – Grinding Wheel Containing Steel

[0084] A grinding wheel containing steel (S45C) was prepared, wherein the center part and the outer periphery of the wheel are integrated.

[0085] Comparative Example 5 - Grinding wheels with different lamination structures

[0086] The grinding wheel was manufactured in the same manner as in Example 1, except that the outer periphery of the wheel was formed by combining a plain weave fabric layer interwoven in the 0° and 90° directions with a twill weave fabric layer interwoven in the 0° and 90° directions, wherein the layer thickness was 15 layers.

[0087] Comparative Example 6 - Grinding wheels with different lamination structures

[0088] The grinding wheel was manufactured in the same manner as in Example 1, except that the outer periphery of the wheel was formed by alternating stacking of 7 layers of woven fabric interlaced in the 0° and 45° directions and 8 layers of woven fabric interlaced in the 0° and 90° directions, with a layer thickness of 15 layers.

[0089] Comparative Example 7 - Grinding wheels with different lamination structures

[0090] The grinding wheel was manufactured in the same manner as in Example 1. The difference from Example 1 is that the surface part of the outer periphery of the wheel is composed of three woven fabric layers interwoven in the 0° and 90° directions, the core part is composed of three woven fabric layers interwoven in the 0° and 90° directions, and the nine unidirectional fabric layers in the middle part are laminated sequentially with cross angles of 0 / 20 / 40 / 60 / 80 / -80 / -60 / -40 / -20°.

[0091] Physical performance analysis:

[0092] Density (g / cm³) 3 ): Measurement using an automatic density meter

[0093] Tensile strength (MPa): Measured using a UTM (Universal Testing Machine).

[0094] Damping coefficient: Measured under dynamic mechanical analysis (DMA) conditions, measuring the material's response to stress or strain in the form of a DMA sinusoidal oscillation (test conditions: frequency: 1Hz, temperature: 30℃, amplitude: 10μm). Dimensionless. Steel: <0.0001, Aluminum: 0.000187.

[0095] Tensile stiffness (GPa): Measured using a UTM (Universal Testing Machine).

[0096] Spindle load: Monitored through load measurement during machining.

[0097] Parallelism (μm): Hommel-Etamic GmbH unit

[0098] Cylindricity (μm): Hommel-Etamic GmbH unit

[0099] Roundness (μm): Hommel-Etamic GmbH unit

[0100] Flatness (μm): Hommel-Etamic GmbH unit

[0101] Roughness (μm): Hommel-Etamic GmbH unit

[0102] Combustion test: Measurements were performed using an optical microscope.

[0103] Test Example 1 - Physical Property Test of Grinding Wheel

[0104] Grinding wheels according to Examples 1 to 4 were manufactured, and their physical properties were tested. The results are shown in Table 1 below:

[0105]

[0106] Table 1

[0107] As can be clearly seen from Table 1, compared with the grinding wheels according to Comparative Examples 1 to 4, the grinding wheel according to Example 1, despite its lower density, has higher tensile strength and damping coefficient related to the damping effect. In particular, it has been confirmed that both the tensile strength and damping coefficient are higher than those of the grinding wheel with the twill structure according to Comparative Example 1. Furthermore, grinding wheels according to Examples 1 and 5 to 7 were manufactured, and their physical properties were tested. The results are shown in Table 2 below:

[0108]

[0109] Table 2

[0110] *Pin grinding wheel size: 50T standard, manufacturing and lamination require approximately 260 layers (1 layer = 0.288).

[0111] As can be clearly seen from Table 2, for the grinding wheel according to the embodiment, the woven fabric layers in the core and surface portions of the outer periphery of the wheel are interwoven in the 0° and 90° directions, and the unidirectional fabric layer in the middle portion is laminated at a 90° cross angle. Compared with the grinding wheels of Comparative Examples 5-7 that do not adopt the above-mentioned lamination direction, the manufacturing process is simple, the cost is low, and the mechanical properties such as tensile stiffness and tensile strength are excellent.

[0112] Specifically, in the grinding wheel according to the present invention, the fiber-reinforced plastic (FRP) layer in the outer peripheral portion of the outer surface of the wheel center is set in different positions and thicknesses according to the weaving pattern. Therefore, compared with conventional grinding wheels, it has excellent vibration / shock absorption and cancellation effects as well as excellent mechanical properties.

[0113] Test Example 2 - Using a grinding wheel to test the quality of machined products

[0114] Grinding wheels were manufactured according to Examples 1 and 4, and the quality of the machined crankshaft products was tested using the grinding wheels. The results are shown in Tables 3 and 4 below:

[0115]

[0116] Table 3* (Difference in crank material) Type A is FCD45C, Type B is 44MnsiVS6.

[0117]

[0118] Table 4

[0119] As shown in Table 3, unlike the processed products manufactured using the grinding wheel of Comparative Example 4, the processed products manufactured using the grinding wheel of the embodiment exhibited reduced spindle load, no combustion occurred during the combustion test, and specifications such as parallelism met the required range. Furthermore, as shown in Table 4, in the processed products manufactured using the grinding wheel according to the embodiment, the tool wear of the grinding wheel, i.e., the wear of the abrasive material (CBN) in the grinding section (mm), was reduced by approximately 81% compared to the processed products manufactured using the grinding wheel according to Comparative Example 4. This is believed to be because the grinding wheel of the embodiment according to Test Example 1 has a high damping coefficient, resulting in a larger difference in the absorption of processing impact caused by the damping effect.

[0120] Therefore, the grinding wheel according to the present invention is constructed such that the position and thickness of the fiber-reinforced plastic (FRP) layer in the outer peripheral portion of the outer surface located at the center of the wheel vary depending on the type of woven pattern layer. Thus, compared to conventional grinding wheels, it exhibits superior mechanical properties and excellent vibration / shock absorption and mitigation effects, preventing problems such as cracking and fatigue failure caused by combustion, and improving the quality and productivity of processed products. Furthermore, the grinding wheel of the present invention is lighter than conventional grinding wheels, and the grinding section or outer peripheral portion of the grinding wheel can be detachably attached, thereby reducing replacement time and tool wear.

[0121] The present invention has been described in detail above with reference to preferred embodiments. However, those skilled in the art will understand that changes may be made to these embodiments without departing from the principles or spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A grinding wheel, comprising: The center of the wheel contains steel; as well as The outer circumference of the wheel is disposed on the outer surface of the wheel center portion and is configured such that fiber reinforced plastic (FRP) layers are laminated and bonded in multiple layers in a direction perpendicular to the outer surface of the wheel center portion. The fiber-reinforced plastic layer has at least one woven pattern layer selected from woven fabric layers and unidirectional fabric layers. The outer periphery of the wheel is configured such that a core portion, located at the center of the outer periphery and parallel to a line perpendicular to the outer surface of the wheel center portion, an intermediate portion, located on at least one side of the core portion, and a surface portion located on the intermediate portion are laminated and joined together. Each of the core and the surface portion includes multiple layers of woven fabric. The middle section includes multiple unidirectional fabric layers. The position and thickness of the fiber-reinforced plastic layer vary depending on the type of the woven pattern layer, and The woven pattern layer is laminated with a predetermined thickness range and a predetermined lamination direction.

2. The grinding wheel according to claim 1, wherein, The fiber-reinforced plastic layer comprises at least one selected from the group consisting of carbon fiber reinforced plastic (CFRP), glass fiber reinforced plastic (GFRP), and aramid fiber reinforced plastic (AFRP).

3. The grinding wheel according to claim 1, wherein, The fiber bundles of the fiber-reinforced plastic layer consist of 1k to 24k strands of yarn per layer.

4. The grinding wheel according to claim 1, wherein, The core has a layer thickness of 8 to 12 layers.

5. The grinding wheel according to claim 1, wherein, The thickness of the surface layer is 22 to 28 layers.

6. The grinding wheel according to claim 1, wherein, The woven fabric layer is a woven fabric layer interwoven in the 0° and 90° directions.

7. The grinding wheel according to claim 1, wherein, The woven fabric layer is plain woven.

8. The grinding wheel according to claim 1, wherein, The thickness of the unidirectional fabric layer is 90 to 100 layers.

9. The grinding wheel according to claim 1, wherein, The unidirectional fabric layers are laminated at cross angles of 85° to 95° to form multiple layers.

10. The grinding wheel according to claim 1, further comprising a grinding section disposed on the outer surface of the outer periphery of the wheel and comprising abrasive material.

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