Rotary component

Abstract

This rotary component comprises a composite structure including a metal matrix and a plurality of ceramic particles dispersed in the metal matrix, and has a Young's modulus of 120 GPa or more.

Description

Rotating parts

[0001] This disclosure relates to a rotating component. This disclosure claims priority to Japanese Application No. 2023-116006, filed July 14, 2023, and incorporates by reference all of the contents of said Japanese application.

[0002] In some cases, a machine tool for machining includes a rotating part that rotates during use. U.S. Patent Publication No. 2007 / 0129994 discloses a cutter body that holds a cutting tip as a rotating part. U.S. Patent Publication No. 2007 / 0129994 discloses a flange that holds a blade as a rotating part.

[0003] JP 2012-86338 A JP 2022-112635 A

[0004] The rotating component of the present disclosure has a composite structure including a metal matrix and a plurality of ceramic particles dispersed in the metal matrix, and has a Young's modulus of 120 GPa or more.

[0005] FIG. 1 is a schematic diagram showing an example of a rotating part according to an embodiment. FIG. 2A is an enlarged schematic diagram of a cross section of the rotating part shown in FIG. 1. FIG. 2B is a micrograph of the cross section of the rotating part shown in FIG. 1. FIG. 3 is a schematic diagram of a dicing device described in Application Example 1. FIG. 4 is a partially exploded perspective view of the dicing device shown in FIG. 3. FIG. 5 is a partial cross-sectional view of the dicing device shown in FIG. 3. FIG. 6 is an enlarged view of a portion where a blade is held in FIG. 5. FIG. 7 is a schematic perspective view of a gear described in Application Example 2. FIG. 8 is a schematic exploded perspective view of a motor described in Application Example 3. FIG. 9 is a schematic perspective view of a cutter body described in Application Example 4. FIG. 10 is a schematic view of a test piece used in a tensile test described in a test example. FIG. 11 is a schematic view of a test device used in a wear resistance test described in a test example.

[0006] [Problem to be Solved by the Present Disclosure] When the rotation speed of a rotating component increases, the rotating component may be distorted by centrifugal force. Thin, plate-shaped rotating components are particularly susceptible to distortion. For example, when a rotating component holds a machining tool of a processing device, distortion of the rotating component may result in a decrease in machining accuracy. Furthermore, when the mass of a rotating component is large, centrifugal force tends to increase, which can lead to a problem of increased distortion of the rotating component. One of the objects of the present disclosure is to provide a rotating component that is less susceptible to distortion during rotation.

[0007] [Advantages of the Present Disclosure] The rotating component of the present disclosure is less likely to be distorted during rotation.

[0008] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described.

[0009] <1> The rotating component of the present disclosure has a composite structure including a metal matrix and a plurality of ceramic particles dispersed in the metal matrix, and has a Young's modulus of 120 GPa or more.

[0010] A component having a composite structure in which multiple ceramic particles are dispersed in a metal matrix is ​​known as a metal matrix composite (hereinafter, MMC). Components made of MMC are lighter than components made solely of metal. Therefore, the centrifugal force acting on a rotating component of the present disclosure made of MMC is smaller than that acting on a rotating component made solely of metal. Therefore, the rotating component of the present disclosure is less likely to be distorted even when centrifugal force acts on the rotating component during rotation.

[0011] The rotating component of the present disclosure has a Young's modulus of 120 GPa or more. Young's modulus is also called the longitudinal elastic modulus. Young's modulus is determined from the amount of strain (deformation) due to tension or compression in one direction. The Young's modulus of a rotating component is an indicator of the resistance of the rotating component to deformation. A rotating component having a Young's modulus of 120 GPa or more is less likely to be distorted even when centrifugal force acts on the rotating component during rotation. The rotating component of the present disclosure is less likely to be deformed, including deflected, during rotation.

[0012] <2> In the rotating part described in <1> above, the specific gravity may be 5 or less.

[0013] Specific gravity is the density of the rotating part divided by the density of water. Specific gravity is a dimensionless number. The density of water is 1 g / cm ３ Therefore, the density of the rotating parts is 5 g / cm ３ Such rotating components are lightweight, reducing the centrifugal forces acting on the rotating components when they are rotated.

[0014] <3> In the rotating part described in <1> or <2> above, the metal matrix may be made of an alloy containing titanium, and the plurality of ceramic particles may be made of a ceramic containing titanium.

[0015] The rotating part described in the above item <3> is lightweight and has a high Young's modulus. In addition, the rotating part has excellent mechanical properties, such as hardness and wear resistance.

[0016] An example of an alloy containing titanium (Ti) is 64Ti, which contains titanium, aluminum (Al), and vanadium (V). 64Ti is a titanium alloy containing 6% by mass of aluminum and 4% by mass of vanadium, with the total mass of the alloy being 100% by mass. 64Ti is lightweight and has excellent strength. An example of a ceramic containing titanium is titanium boride.

[0017] <4> In the rotating part described in <3> above, when the total volume of the metal matrix and the plurality of ceramic particles is 100 volume %, the volume ratio of the plurality of ceramic particles may be 5 volume % or more and 35 volume % or less.

[0018] In a rotating part having a composite structure in which titanium-containing ceramic particles are dispersed in a titanium-containing alloy, if the volume fraction of the ceramic particles is 5 volume % or more, the effect of improving the Young's modulus of the rotating part due to the inclusion of the ceramic particles is likely to be obtained.If the volume fraction of the ceramic particles in the rotating part is 35 volume % or less, a rotating part with a high Young's modulus and excellent impact resistance is likely to be obtained.

[0019] <5> The rotating part according to any one of <1> to <4> above includes a holding member configured to hold the rotary tool.

[0020] By holding the rotary tool with a holding member made of rotating parts that are less likely to be distorted by rotation, it is possible to easily maintain a predetermined machining accuracy with the rotary tool for a long period of time. The rotary tool is, for example, a disk-shaped blade as described in the embodiment described below. The rotary tool may also be, for example, a cutting tip.

[0021] <6> In the rotating part described in <5> above, the rotating tool may be a circular blade, and the holding member may include a first member and a second member that sandwich the blade.

[0022] By sandwiching the blade between the first and second members, which are made of rotating parts that are less likely to distort due to rotation, the blade's rotational trajectory is more stable. As a result, when cutting an object with the blade, the width of the cutting margin tends to be smaller. In addition, because the blade is less likely to vibrate, it is less likely to cause intermittent impacts on the object, and the load on parts of the object other than the cutting point is smaller.

[0023] <7> In the rotating part according to any one of the above items <1> to <4>, the rotating part may be any one of a gear, a rotor body of a motor, and a cutter body that holds a cutting tool.

[0024] Gears, motor rotor bodies, and cutter bodies are required to maintain a certain level of dimensional accuracy during rotation. Rotating parts with a high Young's modulus of 120 GPa or more can meet this requirement, making them suitable for gears, motor bodies, and cutter bodies.

[0025] [Details of the embodiments of the present disclosure] Specific examples of rotating components of the present disclosure will be described below with reference to the drawings. The same reference numerals in the drawings indicate the same or equivalent parts. The sizes of the components shown in each drawing are expressed for the purpose of clarity of explanation and do not necessarily represent the actual dimensions. Note that the present invention is not limited to these examples, but is defined by the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included.

[0026] 1 shows an example of a rotating component 1 according to an embodiment. The rotating component 1 is attached to a device that rotates the rotating component 1, and rotates around a rotation axis 1S indicated by a dashed line during use. The rotating component 1 has a shape, structure, and size suitable for being rotated when used.

[0027] The shape of the rotating component 1 is not particularly limited as long as the center of gravity of the rotating component 1 is located on the rotation axis 1S. The rotating component 1 has, for example, a disk shape or a cylindrical shape. The disk-shaped or cylindrical rotating component 1 may have a blind hole formed therein into which a shaft portion, such as a spindle, that rotates the rotating component 1 is fitted. The rotating component 1 may also have an annular or cylindrical shape with a through-hole into which a shaft portion, such as a spindle, that rotates the rotating component 1 is fitted. The rotating component 1 may also have a polygonal shape, such as a triangle, or a wavy shape like a gear, when viewed in the direction along the rotation axis 1S. The rotating component 1 shown in FIG. 1 is an annular plate material having a through-hole 1h.

[0028] The rotating component 1 is made of a sintered body. The rotating component 1 has a composite structure 10 shown in Fig. 2A. The composite structure 10 includes a metal matrix 11 and a plurality of ceramic particles 12 dispersed in the metal matrix 11. The composite structure 10 having such a structure is called a metal matrix composite (hereinafter, referred to as MMC).

[0029] The metal matrix 11 is, for example, a titanium alloy, an aluminum alloy, or stainless steel. Examples of titanium alloys include Ti-5Al-2.5Sn, Ti-6Al-4V, Ti-3Al-2.5V, Ti-6Al-4V-2Sn, Ti-15V-3Cr-3Sn-3Al, Ti-13V-11Cr-3Al, and Ti-3Al-8V-6Cr-4Mo-4Zr. Sn is tin, Cr is chromium, Mo is molybdenum, and Zr is zirconium. The numbers in the composition of the titanium alloys listed above represent the mass percentage of each element when the mass of the titanium alloy is taken as 100 mass%. In particular, Ti-6Al-4V, also known as 64Ti, has excellent strength.

[0030] The ceramic particles 12 are, for example, borides containing the metal derived from the metal matrix 11. If the metal matrix 11 is a titanium alloy, the ceramic is, for example, titanium boride (TiB).

[0031] A rotating component 1 made of an MMC containing a plurality of ceramic particles 12 is lighter than a rotating component made only of metal. Therefore, when the rotating component 1 rotates at high speed, the centrifugal force acting on the rotating component 1 is small. Therefore, the rotating component 1 is less likely to be distorted even when centrifugal force acts on the rotating component 1 during rotation. The ceramic particles 12 contained in the rotating component 1 also contribute to improving the Young's modulus of the rotating component 1.

[0032] The Young's modulus of the rotating component 1 is 120 GPa or more. A rotating component 1 having a Young's modulus of 120 GPa or more is less likely to be distorted even when centrifugal force acts on the rotating component 1 during rotation. The Young's modulus is determined by a tensile test described below. The Young's modulus of the rotating component 1 may be, for example, 125 GPa or more, 130 GPa or more, or even 140 GPa or more. From the perspective of the effects of the rotating component 1 obtained by having a high Young's modulus, there is no upper limit to the Young's modulus of the rotating component 1. From the perspective of ease of manufacturing the rotating component 1, the upper limit of the Young's modulus of the rotating component 1 is 250 GPa.

[0033] The tensile strength of the rotating component 1 may be, for example, 1000 MPa or more. A rotating component 1 with a tensile strength of 1000 MPa or more is less likely to irreversibly deform when strain occurs during high rotation. The tensile strength may be, for example, 1050 MPa or more, or 1100 MPa or more. From the perspective of the effects of the rotating component 1 obtained by having a high tensile strength, there is no upper limit to the tensile strength of the rotating component 1. From the perspective of ease of manufacturing the rotating component 1, the upper limit of the tensile strength of the rotating component 1 is 2000 MPa.

[0034] The specific gravity of the rotating part 1 is, for example, 5 or less. The specific gravity of the rotating part 1 is a value obtained by dividing the density of the rotating part 1 by the density of water. The density of the rotating part 1 can be determined, for example, by Archimedes' method. The unit of density is g / cm. ３The density of the rotating component 1 varies depending on the composition of the composite structure 10. A rotating component 1 having a specific gravity of 5 or less is relatively light, and the centrifugal force acting on the rotating component 1 when the rotating component 1 rotates is relatively reduced. The smaller the specific gravity of the rotating component 1, the smaller the centrifugal force. The specific gravity of the rotating component 1 may be, for example, 4.9 or less, or 4.7 or less.

[0035] When the total volume of the metal matrix 11 and the plurality of ceramic particles 12 in the rotating part 1 is 100 volume %, the volume ratio VR of the plurality of ceramic particles 12 is, for example, 5 volume % or more and 35 volume % or less. The volume ratio is the ratio V1 / V0 of the volume V1 of the plurality of ceramic particles 12 to the total volume V0 of the metal matrix 11 and the plurality of ceramic particles 12, expressed as a percentage.

[0036] If the volume fraction VR is 5 vol% or more, the effect of improving the Young's modulus of the rotating part 1 due to the inclusion of the ceramic particles 12 is likely to be obtained. Furthermore, if the volume fraction VR is 35 vol% or less, a rotating part 1 having a high Young's modulus and excellent impact resistance is likely to be obtained. The volume fraction VR may be, for example, 5 vol% to 30 vol%, 7 vol% to 25 vol%, or 9 vol% to 20 vol%.

[0037] The volume ratio VR can be determined, for example, by image analysis of a micrograph of the cross section of the rotating component 1 shown in FIG. 2B . Specifically, an observation field having a predetermined area on the cross section is analyzed using image analysis software (ImageJ, a public domain image processing software). In the image analysis, the metal matrix 11 and the ceramic particles 12 in the observation field are extracted. Next, the grayscale image is binarized to calculate the area of ​​the metal matrix 11 and the area of ​​the plurality of ceramic particles 12. The grayscale is set to 256 gradations, and the light range from 0 to 120 is determined as the metal matrix, and the dark range from 121 to 256 is determined as the ceramic particles. Voids are not included in the area of ​​the metal matrix 11. The sum of the area of ​​the metal matrix 11 and the area of ​​the plurality of ceramic particles 12 is set to 100 area %, and the area ratio of the plurality of ceramic particles 12 to the total area of ​​the metal matrix 11 and the plurality of ceramic particles 12 is calculated. In the present disclosure, the area ratio of the plurality of ceramic particles 12 obtained from a cross section of the rotating component 1 is considered to be the volume ratio VR of the plurality of ceramic particles 12 in the rotating component 1.

[0038] As an example, a manufacturing method of a rotating part 1 made of a titanium-based sintered body will be described below. In the rotating part 1 made of a titanium-based sintered body, the metal matrix 11 is made of a titanium alloy, and the ceramic particles 12 are made of a ceramic containing titanium. This manufacturing method includes the following steps: - A step of preparing raw material powder - A step of mixing the raw material powder with a lubricant to prepare a mixed powder - A step of press-molding the mixed powder - A step of cutting a green compact - A step of removing the lubricant - A step of sintering the green compact - A step of compressing the titanium-based sintered body by hot isostatic pressing - A step of finishing Each step will be described in detail below.

[0039] <Step of Preparing Raw Material Powder> The raw material powder contains titanium. The raw material powder may contain powder composed of pure titanium or powder composed of a titanium alloy. The raw material powder may be composed of powder composed of pure titanium and powder containing an element capable of alloying with titanium. The raw material powder may be composed of powder composed of a titanium alloy and powder containing an element capable of alloying with titanium. The element other than titanium in the raw material powder is, for example, Al, V, Sn, Cr, Mo, or Zr. The element other than titanium is appropriately selected depending on the composition of the metal matrix 11 to be prepared. An example of a specific raw material powder includes Ti powder composed of pure titanium and Al-V powder composed of a compound of aluminum and vanadium. Using a raw material powder containing Ti powder and Al-V powder, a metal matrix 11 composed of a Ti-6Al-4V alloy is obtained.

[0040] The raw material powder further contains ceramic powder. The ceramic powder is, for example, titanium diboride (TiB ２ The rotating component 1 made of MMC is manufactured by using raw material powder containing ceramic powder.

[0041] The particle size of the raw material powder ranges, for example, from 0.1 μm to 100 μm. The particle size of the raw material powder can be measured, for example, using a particle size distribution measuring device. When fine raw material powder is pressure-molded, air is likely to be trapped in the gaps between the ceramic particles that make up the green compact, which tends to increase the oxygen concentration of the green compact. The oxygen contained in the green compact may degrade the mechanical properties of the titanium-based sintered body obtained by sintering the green compact. If the particle size of the raw material powder is 0.1 μm or more, aggregation during mixing can be suppressed. If the particle size of the raw material powder is 100 μm or less, the density of the green compact and the sintered body is likely to be high. The particle size of the raw material powder may be, for example, from 0.5 μm to 90 μm.

[0042] <Step of Mixing Raw Material Powder and Lubricant> The mixing method for mixing the raw material powder and the lubricant is not particularly limited. For example, the raw material powder and the lubricant may be mixed using a ball mill, an attritor, or a jet mill. The mixing method using a ball mill, an attritor, or a jet mill imparts high energy to the raw material powder. The raw material powder and the lubricant may also be mixed using a V-type mixer. The mixing method using a V-type mixer imparts relatively low energy to the raw material powder.

[0043] The lubricant is, for example, stearic acid, zinc stearate, stearic acid amide, or ethylene bisstearic acid amide. Stearic acid, in particular, vaporizes at temperatures above 270° C., making it suitable for the manufacturing method of the titanium-based rotating component 1.

[0044] The mixing ratio of the lubricant to the raw material powder is, for example, 0.05% by mass or more and 0.5% by mass or less, when the raw material powder is 100% by mass. If the amount of lubricant mixed with 100% by mass of the raw material powder is 0.05% by mass or more, the powder compact can be easily cut in the step of cutting the powder compact described below. If the amount of lubricant mixed with 100% by mass of the raw material powder is 0.5% by mass or less, the amount of lubricant relative to the raw material powder is not too large, and the density of the powder compact can easily be increased. The amount of lubricant mixed may be 0.2% by mass or more and 0.5% by mass or less, or 0.3% by mass or more and 0.4% by mass or less.

[0045] <<Step of Pressing the Raw Powder>> Pressing is performed, for example, by cold isostatic pressing. The pressing temperature is between 0°C and 50°C. The cold isostatic pressing mold is made of a non-metallic elastic material, such as urethane rubber, acrylic resin, acrylic resin containing elastomer, or polylactic acid resin. Because the cold isostatic pressing mold is not metallic, titanium does not seize onto the mold. The shape of the powder compact obtained by cold isostatic pressing is relatively simple. For example, the powder compact has a cylindrical or cylindrical shape.

[0046] The molding pressure is appropriately selected depending on the material of the raw material powder and the density of the green compact. For example, the molding pressure is 200 MPa or more. The molding pressure may be 350 MPa or more or 500 MPa or more. The upper limit of the molding pressure depends on the capacity of the equipment. For example, the upper limit of the molding pressure is 800 MPa. The higher the molding pressure, the higher the density of the green compact tends to be.

[0047] <Step of Cutting the Powder Compact> The powder compact is machined into a shape similar to that of the rotating component 1 by cutting. The cutting is performed, for example, using a lathe or a machining center. The cutting may be continuous cutting using a cutting tool or intermittent cutting using a rotary tool. Because the powder compact of the present disclosure contains a lubricant, the cutting tool is less likely to be damaged during cutting. Because the cutting tool is less likely to be damaged, the increase in cutting costs associated with replacing the cutting tool can be suppressed. Furthermore, the cutting accuracy is less likely to decrease, and the surface quality of the cut powder compact is improved.

[0048] The greater the lubricant content in the powder compact, the less likely the cutting tool is to be damaged and the more likely the surface quality of the powder compact is to be improved. The lubricant content relative to the raw material powder in the powder compact can be considered to be the same as the amount of lubricant mixed with the raw material powder when the raw material powder and the lubricant are mixed.

[0049] <<Lubricant Removal Process>> In the lubricant removal process, the powder compact is heat-treated in an inert atmosphere at 400°C or lower. The inert atmosphere is, for example, a nitrogen atmosphere or an argon atmosphere. In an inert atmosphere at 400°C or lower, titanium contained in the powder compact is unlikely to be nitrided. Because titanium nitride is brittle, if titanium nitride is generated in the powder compact, the mechanical properties of the titanium-based sintered body obtained by sintering the powder compact may be reduced. Titanium nitride may inhibit the sintering of the powder compact, reducing the mechanical properties of the titanium-based sintered body. Even when the powder compact is heat-treated in an argon atmosphere, titanium nitride may be generated in an argon atmosphere above 400°C because the powder compact may contain air.

[0050] Stearic acid vaporizes at temperatures above 270°C. A powder compact containing stearic acid as a lubricant is heat-treated, for example, in an inert atmosphere at a temperature of 270°C to 380°C. If the temperature range of the inert atmosphere is 270°C to 380°C, most of the stearic acid is removed from the powder compact. If the inert atmosphere is 380°C or lower, the generation of titanium nitride in the powder compact can be effectively suppressed.

[0051] The heat treatment time during which the powder compact is maintained within the above temperature range is, for example, 10 minutes or more and 8 hours or less. If the heat treatment time is 10 minutes or more, the temperature at the center of the powder compact becomes sufficiently high, making it easier to remove the lubricant from the entire powder compact. If the heat treatment time is 8 hours or less, the time required to produce the titanium-based sintered body does not become too long. The heat treatment time may be 3 hours or more and 6 hours or less. After the heat treatment, the powder compact is cooled to room temperature in a furnace.

[0052] <Step of Sintering the Powder Compact> In the step of sintering the powder compact, the powder compact from which the lubricant has been removed is sintered in a vacuum atmosphere. The atmospheric pressure is, for example, 0.1 Pa or less. The atmospheric temperature is appropriately selected depending on the material of the raw material powder. For example, the atmospheric temperature is 1100°C or higher and 1400°C or lower.

[0053] The sintering time is, for example, 1 hour or more and 25 hours or less. If the sintering time is 1 hour or more, the entire powder compact is likely to be sintered sufficiently. If the sintering time is 25 hours or less, the time required to produce the titanium-based sintered body is not too long. The sintering time may be 8 hours or more and 18 hours or less. The titanium-based sintered body is cooled to room temperature in the furnace.

[0054] Even a vacuum atmosphere contains a small amount of air. When the powder compact is sintered, the nitrogen in the air may react with the titanium contained in the compact. By embedding the powder compact in zirconia balls and placing a getter made of titanium pieces on top of the zirconia balls, the amount of titanium nitride in the titanium-based sintered compact can be reduced.

[0055] The relative density of the titanium-based sintered body is, for example, 95% by volume or more. In the present disclosure, relative density refers to the volume ratio of the solid portion to the volume of the object being measured. Even if the relative density of the powder compact before sintering is the same, the relative density of the titanium-based sintered body will change if the method for producing the powder compact is different. For example, when a powder compact made from a raw material powder consisting of pre-alloy powder is sintered, the relative density of the titanium-based sintered body is unlikely to be high. Pre-alloy powder is a powder having the same composition as the titanium alloy that makes up the titanium-based sintered body. When a powder compact made from a raw material powder that is a mixture of multiple types of powder is sintered, the relative density of the titanium-based sintered body is likely to be high.

[0056] The titanium alloy constituting the metal matrix 11 is, for example, Ti-5Al-2.5Sn, Ti-6Al-4V, Ti-3Al-2.5V, Ti-6Al-4V-2Sn, Ti-15V-3Cr-3Sn-3Al, Ti-13V-11Cr-3Al, or Ti-3Al-8V-6Cr-4Mo-4Zr. The ceramic particles 12 dispersed in the metal matrix 11 are titanium boride (TiB). Titanium boride is obtained by dissolving titanium diboride (TiB) mixed in the raw material powder. ２ ) precipitates derived from

[0057] <<Step of compressing the titanium-based sintered body by hot isostatic pressing>> The relative density of the titanium-based sintered body is further increased by hot isostatic pressing. The relative density of the titanium-based sintered body to be subjected to hot isostatic pressing is 95% or more. It is difficult to increase the density of a titanium-based sintered body with a relative density of less than 95% by hot isostatic pressing. Hot isostatic pressing is not essential.

[0058] The temperature of the hot isostatic press is appropriately selected depending on the composition of the sintered body. For example, the temperature of the hot isostatic press is 800°C or higher and 1100°C or lower. The processing time is, for example, 30 minutes or higher and 6 hours or lower. If the processing time is 30 minutes or higher, the relative density of the sintered body will be sufficiently high. If the processing time is 6 hours or lower, the production time of the sintered body will not be too long. The processing time may be 1 hour or higher and 4 hours or lower. The sintered body is cooled to room temperature in the hot isostatic press. The pressure is, for example, 150 MPa or higher.

[0059] <<Finishing Process>> In the finishing process, for example, the surface of the titanium-based sintered body is ground. Grinding allows the titanium-based sintered body to have the desired dimensions and smooths the surface of the titanium-based sintered body. Grinding also removes impurities that have concentrated on the surface of the titanium-based sintered body from the surface of the titanium-based sintered body. The impurities are, for example, titanium oxide, titanium carbide, or titanium nitride. Removing the impurities from the surface of the sintered body improves the mechanical properties of the titanium-based sintered body. The titanium-based sintered body that has undergone finishing is the rotating part 1 of the present disclosure.

[0060] <Application Example 1> An example of an apparatus to which the rotating component 1 is applied will be described with reference to Figs. 3 to 6. Fig. 3 is a schematic perspective view of a dicing apparatus 9, which is an example of an apparatus equipped with the rotating component 1. The dicing apparatus 9 is an apparatus for cutting a wafer 8 on which a plurality of integrated circuits are formed, and separating the wafer 8 into a plurality of chips. The dicing apparatus 9 includes a rotation mechanism 9M having a blade 90 for cutting the wafer 8.

[0061] As shown in the exploded perspective view of Fig. 4 , the rotation mechanism 9M includes a circular ring-shaped blade 90, and a first member 91 and a second member 92 that sandwich the blade 90. The first member 91 and the second member 92 are both rotating components 1 having a composite structure 10. The rotating component 1 is a holding member configured to hold the blade 90, which is a rotating tool. As shown in Fig. 5 , the blade 90 is attached to a shaft portion 95S of a spindle 95 by a nut 93 while being sandwiched between the first member 91 and the second member 92.

[0062] The first member 91 is a generally cylindrical member having a through hole 91h. The first member 91 includes, in order from the portion facing the spindle 95, a first cylindrical portion 91A, an annular portion 91B, and a second cylindrical portion 91C. As shown in FIG. 5 , a shaft portion 95S of the spindle 95 passes through the through hole 91h. An end face of the first cylindrical portion 91A is abutted against the spindle 95.

[0063] As shown in the partially enlarged view of FIG. 6 , the annular portion 91B includes a base portion 910 including a through hole 91h (see FIG. 5 ) and a holding portion 915 disposed on the outer periphery of the base portion 910. In FIG. 6 , the boundary between the base portion 910 and the holding portion 915 is virtually indicated by a two-dot chain line. The holding portion 915 is thinner than the base portion 910, and a step is formed between the base portion 910 and the holding portion 915 on the surface of the first member 91 facing the second member 92. The surface of the holding portion 915 facing the second member 92 is a holding surface 91P that holds the blade 90, which will be described later. The holding portion 915 becomes thinner toward the outer periphery. The holding surface 91P is a plane perpendicular to the axis of the through hole 91h. The surface opposite the holding surface 91P has an inclined surface that slopes toward the second member 92 as it approaches the outer periphery of the holding portion 915.

[0064] The second member 92 is a generally annular member having a through-hole 92h (see FIG. 5). The second cylindrical portion 91C of the first member 91 passes through the through-hole 92h. The second member 92 includes, in order from the portion facing the first member 91, an annular portion 92D and a cylindrical portion 92E. The annular portion 92D includes a base portion 920 including the through-hole 92h and a retaining portion 925 disposed on the outer periphery of the base portion 920. In FIG. 6, the boundary between the base portion 920 and the retaining portion 925 is virtually indicated by a two-dot chain line. The retaining portion 925 protrudes toward the first member 91 more than the base portion 920. The outer periphery of the annular portion 92D protrudes toward the first member 91 further than the remaining portion. The surface of the outer periphery of the annular portion 92D facing the first member 91 is a retaining surface 92P that retains the blade 90, which will be described later. The holding surface 92P is a plane that is approximately perpendicular to the axis of the through hole 92h. Therefore, only the outer periphery of the holding surface 92P is in contact with the blade 90. The surface of the holding portion 925 opposite the holding surface 92P has an inclined surface that is inclined so as to approach the first member 91 as it approaches the outer periphery of the holding portion 925.

[0065] The blade 90 is a circular plate member. The blade 90 is sandwiched between a holding surface 91P of the first member 91 and a holding surface 92P of the second member 92.

[0066] The nut 93 is threadedly coupled to the outer periphery of the second cylindrical portion 91C of the first member 91. Threads and thread grooves are not shown in Fig. 5. By tightening the nut 93, the blade 90 is firmly held between the first member 91 and the second member 92.

[0067] In the dicing device 9 of the application example, the blade 90, the first member 91, and the second member 92 rotate at an extremely high speed. If the first member 91 and the second member 92 are rotating components 1 having a composite structure 10, the holding portion 915 of the first member 91 and the holding portion 925 of the second member 92 are less likely to be distorted by centrifugal force. Therefore, the holding state of the blade 90 by the holding portion 915 and the holding portion 925 is stable, and the rotational trajectory of the blade 90 is more likely to be stable. When the rotational trajectory of the blade 90 is stable, the width of the cutting margin is more likely to be small when cutting the wafer 8. When the rotational trajectory of the blade 90 is stable, intermittent impacts are less likely to act on the wafer 8, and the load on portions of the wafer 8 other than the cutting location is smaller.

[0068] The rotating component 1 may be applied to, for example, the cutter body of a cutting device shown in Patent Document 1. The cutter body is a generally cylindrical member that holds multiple cutting tips. The multiple cutting tips are arranged at intervals on the outer periphery of the end face of the cutter body. If this cutter body is made of an MMC having the same or similar composite structure 10 as the rotating component 1, the rotational trajectories of the multiple cutting tips are likely to be stable. As a result, the machining accuracy of the cutting device is likely to be improved.

[0069] <Application Example 2> An example in which the rotating part 1 constitutes a gear 2 will be described with reference to Fig. 7. The gear 2 shown in Fig. 7 is a helical gear used in a reducer.

[0070] The meshing accuracy between the gear 2 shown in Figure 7 and another gear that meshes with the gear 2 has a significant effect on power transmission efficiency and noise. In recent years, there has been an increasing demand for improved power transmission efficiency and reduced noise in reducers. The gear 2 is not only required to be finished with extremely high dimensional accuracy during manufacture, but also to maintain high dimensional accuracy during use. A gear 2 with a high Young's modulus of 120 GPa or more can meet these requirements.

[0071] <Application Example 3> An example in which the rotating part 1 constitutes a rotor body 30 of a motor 3 will be described with reference to Fig. 8. Fig. 8 is a schematic exploded perspective view of the motor 3.

[0072] The motor 3 includes two stators 31, 32 and a rotor body 30 sandwiched between the stators 31, 32. The motor 3 is a so-called double-stator axial gap motor. The motor 3 may also be a single-stator axial gap motor. The stators 31, 32 include a core 35 and a coil 36. The coil 36 is disposed on the outer periphery of teeth 350, which are part of the core 35.

[0073] The rotor body 30 is an annular plate having a through hole 30h. A shaft (not shown) is disposed in the through hole 30h. The rotor body 30 has a plurality of recesses 30c arranged to surround the through hole 30h. A magnet 30M is disposed in each recess 30c. The rotor body 30 not only holds the magnets 30M but also plays a role in positioning the magnets 30M.

[0074] In the motor 3 having the above configuration, when an AC current is applied to the coils 36, a rotating magnetic field is generated in the stators 31 and 32. The rotating magnetic field attracts or repels the magnets 30M, causing the rotor body 30 to rotate. The rotor body 30 rotates at high speeds of tens of thousands of rpm (rotations per minute). Therefore, the rotor body 30 must be made of a lightweight, high-strength material. The dimensional accuracy of the rotor body 30 affects the torque of the axial gap motor, the rotational speed of the rotor body 30, and the rotational stability of the rotor body 30. The high dimensional accuracy of the rotor body 30 must be maintained even during rotation. A rotor body 30 with a high Young's modulus of 120 GPa or greater can meet this requirement.

[0075] <Application Example 4> An example in which the rotating part 1 constitutes a cutter body 4 will be described with reference to Fig. 9. The cutter body 4 shown in Fig. 9 is a jig that holds a cutting tip 40 used to process a workpiece by milling or the like. The cutter body 4 is a roughly cylindrical member having a through hole 4h. A recess that holds the cutting tip 40 is formed on the outer periphery of the cutter body 4. The cutting tip 40 is fixed to the cutter body 4 by a screw.

[0076] If the cutter body 4, which rotates at high speed around the rotation axis 1S, is distorted, there is a risk that the surface properties, including the smoothness of the machined surface, will deteriorate. It is required that the cutter body 4 is resistant to distortion during rotation. A cutter body 4 having a high Young's modulus of 120 GPa or more can meet this requirement.

[0077] <Test Examples> <Test Example 1> In Test Example 1, the mechanical properties of the material constituting the rotating part were investigated. The mechanical properties of the rotating part were equal to the mechanical properties of the material constituting the rotating part. The mechanical properties investigated were density, Young's modulus, tensile strength, wear resistance, and Rockwell hardness. The samples prepared in Test Example 1 were as follows:

[0078] [Sample No. 100] Sample No. 100 is a melt made of 64 titanium alloy. The melt of Sample No. 100 was produced by pouring molten 64 titanium alloy into a mold. In the tables described below, 64 titanium alloy will be referred to as "64Ti."

[0079] [Sample No. 1] Sample No. 1 is an MMC having the composite structure 10 shown in Figures 2A and 2B. In this MMC, the metal matrix 11 is composed of 64 titanium alloy, and the ceramic particles 12 are composed of TiB. In the tables described below, this type of MMC will be referred to as "64Ti-MMC."

[0080] In preparing Sample No. 1, a first powder composed of an Al-V compound, a second powder composed of pure titanium, and a TiB ２The ceramic powders were prepared. The particle size of the first powder was 20 μm or more and 90 μm or less. The particle size of the second powder was 20 μm or more and 45 μm or less. The particle size of the ceramic powder was 0.7 μm or more and 10 μm or less.

[0081] The first powder, the second powder, the ceramic powder, and the lubricant were mixed to prepare a raw material powder. The ball mill container was made of tungsten carbide. The milling balls charged into the ball mill container were also made of tungsten carbide. The milling balls had a diameter of 10 mm and 50 balls in total. The mixing conditions were 300 rpm and 1 hour.

[0082] The raw material powder was subjected to cold isostatic pressing to produce a cylindrical green compact under a pressure of 390 MPa for a holding time of 30 seconds.

[0083] In the test examples, samples were prepared to examine their mechanical properties, so the powder compact was heat-treated without being machined, and the lubricant stearic acid was removed from the powder compact. Stearic acid facilitates machining of the powder compact. The atmosphere in the inert oven was nitrogen, the heat treatment temperature was 380°C, and the heat treatment time was 4 hours. The temperature rise rate of the inert oven was 5°C / min.

[0084] The lubricant-removed green compact was placed in a sintering furnace and sintered to produce a sintered body. The sintering furnace atmosphere was a vacuum atmosphere of 0.1 Pa or less, the sintering temperature was 1300°C, and the sintering time was 12 hours. The heating rate of the sintering furnace was 6.7°C / min up to 1290°C, and 1°C / min from 1290°C to 1300°C. The sintered body was an MMC having a composite structure 10 comprising a titanium-containing metal matrix 11 and a plurality of ceramic particles 12 dispersed in the metal matrix 11. The composition of the metal matrix 11 was a 64 titanium alloy. TiB ２ The composition of the ceramic particles 12 derived from the above was titanium boride (TiB).

[0085] [Measurement of Relative Density] Relative density is the volume ratio of the solid part to the volume of the object to be measured. The unit of relative density is volume %. The relative density was measured by Archimedes' method.

[0086] The relative density of Sample No. 100 was nearly 100% by volume. Sample No. 100, which was made from an ingot, is considered to have almost no voids.

[0087] For Sample No. 1, the relative density of the green compact before sintering and the relative density of the titanium-based sintered body after sintering were measured. The relative density of the green compact was 75% by volume or more, specifically 80% by volume. The relative density of the titanium-based sintered body was 95% by volume or more, specifically 97% by volume. It was found that the relative density of the titanium-based sintered body was 15% by volume or more, specifically 17% by volume higher than the relative density of the green compact before sintering.

[0088] [Tensile Test] To determine the Young's modulus and tensile strength of each sample, test specimens were prepared from each sample and subjected to tensile tests. A universal testing machine manufactured by Tokyo Koki Testing Instruments Co., Ltd. was used as the tensile tester. The test specimens were prepared by processing the cylindrical powder compacts described above. Figure 10 is a schematic diagram showing the shape of test specimen 5. Test specimen 5 comprises a first grip portion 51, a second grip portion 52, and an intermediate portion 50. The diameter of the intermediate portion 50 was 6.35 mm (millimeters), and the gauge length d between the first gauge point 50A and the second gauge point 50B set on the intermediate portion 50 was 25.4 mm. The tensile test was performed at room temperature, with a strain rate of 1.2 mm / min up to 0.2% yield strength and a strain rate of 12.8 mm / min after 0.2% yield strength. The Young's modulus and tensile strength of each sample were determined based on the stress-strain curves obtained by the tensile test. The unit of Young's modulus is GPa, and the unit of tensile strength is MPa. The test results are shown in Table 1.

[0089] [Hardness] The Rockwell hardness of each sample was measured. The Rockwell hardness tester used was an ADR-A model Rockwell hardness tester manufactured by Akashi Seisakusho Co., Ltd. The measurement was carried out using a C scale with a conical diamond indenter. The unit of Rockwell hardness is HRC. The measurement results of the Rockwell hardness are shown in Table 1.

[0090] [Wear Resistance Test] Test specimens were prepared from each sample and subjected to a wear resistance test. A UMT TriboLab manufactured by Bruker Japan Co., Ltd. was used as the wear tester. The test specimens were prepared by processing the cylindrical powder compacts described above. Figure 11 is a schematic diagram of the test apparatus 7 for the wear resistance test. The test specimen 6 used in this test was cylindrical. In this test, the circumferential surface of the test specimen 6 was pressed against a rotating disk 70, and the amount of wear on the circumferential surface of the test specimen 6 was measured. The material of the disk 70 was SUJ2 as specified in JIS G 4805. The rotation speed of the disk 70 was 600 rpm. The test specimen 6 was pressed against the disk 70 with a load of 30 N. The sliding length of the test specimen 6 was 60 m. The sliding length was the distance the disk 70 moved relative to the test specimen 6 while in contact with it.

[0091] The contact surface of the test piece 6 with the disk 70 was observed under a microscope, and the average length of the wear scar was measured. The length of the wear scar is the length along the rotation direction of the disk 70, and is expressed in μm. In this example, the average length of the wear scar is the average value of the lengths of the wear scar at three different points. The average lengths of the wear scar are shown in Table 1.

[0092]

[0093] The results in Table 1 show that Sample No. 1, which is made of an MMC having a 64Ti metal matrix 11, is superior in all mechanical properties to Sample No. 100, which is made of a 64Ti melt. The rotating component 1 made of Sample No. 1, which has a high Young's modulus and tensile strength, is less susceptible to distortion due to centrifugal force and more likely to return to its original shape when the centrifugal force is removed, compared to the rotating component made of Sample No. 100.

[0094] Regarding wear resistance, the amount of wear of Sample No. 1 was approximately 1 / 5 of the amount of wear of Sample No. 100. Therefore, when a rotating tool is held by a rotating component 1 made of Sample No. 1, the contact surface of the rotating component 1 with the rotating tool is less likely to wear.

[0095] Test Example 2 In Test Example 2, the relationship between the volume fraction of a plurality of ceramic particles in the composite structure of the rotating part, and the specific gravity and Young's modulus was investigated.

[0096] Sample No. 1 of Test Example 2 was the same as Sample No. 1 of Test Example 1. The volume ratio VR of the plurality of ceramic particles 12 in Sample No. 1 was 10 volume %. The volume ratios VR of the plurality of ceramic particles 12 in Samples No. 2, No. 3, No. 4, and No. 5 were 5 volume %, 16.7 volume %, 25 volume %, and 33.3 volume %, respectively. The volume ratios VR were determined by the method of image analysis of the cross section of the sample described in the embodiment.

[0097] The specific gravity and Young's modulus were measured for Samples No. 1 to No. 5. The specific gravity was determined by the method described in the embodiment. The Young's modulus was measured by the same method as in Test Example 1. The measurement results are shown in Table 2.

[0098]

[0099] As shown in Table 2, it was found that the greater the volume ratio of the ceramic particles 12 contained in the rotating part 1, the higher the Young's modulus of the rotating part 1.

[0100] Even when the volume fraction of ceramic particles 12 contained in rotating part 1 increased, there was almost no change in the specific gravity of rotating part 1. This is because the specific gravity of TiB is only slightly smaller than the specific gravity of titanium-64. Although the specific gravities of Samples No. 1 to No. 5 are the same to one decimal place, in reality, the specific gravity decreases as the volume fraction of ceramic particles 12 increases.

[0101] 1 Rotating part 1h Through hole 1S Rotating shaft 10 Composite structure, 11 Metal matrix, 12 Ceramic particles 2 Gear 3 Motor 30 Rotor body, 30c Recess, 30h Through hole, 30M Magnet 31, 32 Stator 35 Core, 36 Coil, 350 Teeth 4 Cutter body 40 Cutting tip 5 Test piece 50 Intermediate part 50A First reference point, 50B Second reference point 51 First grip part, 52 Second grip part 6 Test piece 7 Testing device 70 Disk 8 Wafer 9 Dicing device 9M Rotating mechanism 90 Blade 91 First member 91h Through hole, 91P Holding surface 91A First cylindrical part, 91B Annular part, 91C Second cylindrical part 910 Base part, 915 Holding part, 92 Second member 92h: through hole, 92P: holding surface, 92D: annular portion, 92E: cylindrical portion, 920: base portion, 925: holding portion, 93: nut, 95: spindle, 95S: shaft portion, d: gauge length

Claims

1. A composite structure having a metal matrix and a plurality of ceramic particles dispersed in the metal matrix, Young's modulus is 120 GPa or more, The specific gravity is 5 or less, The tensile strength is 1000 MPa or more, the metal matrix is made of an alloy containing titanium, the plurality of ceramic particles are made of ceramic containing titanium, When the total volume of the metal matrix and the plurality of ceramic particles is 100 volume %, the volume ratio of the plurality of ceramic particles is 5 volume % or more and 35 volume % or less. Rotating parts.

2. A rotating part as described in claim 1, wherein the metal matrix is Ti-6Al-4V.

3. the rotary component includes a retaining member configured to retain a rotary tool; the rotary tool is a disc-shaped blade, The rotating component according to claim 1 or 2, wherein the holding member comprises a first member and a second member that sandwich the blade therebetween.

4. The rotating component according to claim 1 or 2, wherein the rotating component is a gear.

5. A rotating part as described in claim 1 or claim 2, wherein the rotating part is a rotor body of a motor.

6. A rotating part as described in claim 1 or claim 2, wherein the rotating part is a cutter body that holds a cutting tool.

7. A method of manufacturing a ceramic sintered body, comprising the steps of: preparing a raw material powder containing titanium and ceramic powder; mixing the raw material powder with a lubricant to prepare a mixed powder; a step of compacting the mixed powder into a powder compact; a step of cutting the powder compact; removing the lubricant in an inert atmosphere at 400°C or less; sintering the powder compact from which the lubricant has been removed in a vacuum atmosphere; Manufacturing the rotating part according to claim 1 or claim 2, Manufacturing methods for rotating parts.

8. A method for manufacturing a rotating part as described in claim 7, wherein the ceramic is titanium diboride.

9. A method for manufacturing a rotating part as described in Claim 7, wherein the pressure molding process is performed using an isostatic press using a non-metallic elastic body as a molding mold.