JP4331441B2 - Plain bearings and rotating machinery - Google Patents

Description

【００２１】
表１において空隙に充填するセラミック（基材：ＳｉＣ）に対してＳｉＣ繊維と炭素繊維を合わせた繊維の比率を４０％（基材６０％）で一定にした上で、ＳｉＣ繊維と炭素繊維の割合（体積％）を変化させてそれぞれの場合の各種機械的性質を測定した。その結果、繊維としてＳｉＣ繊維だけを用いた場合は摩擦係数が大きく（０．７３〜０．５５）、このＳｉＣ繊維に炭素繊維を少しだけでも（２０％）混合すると摩擦係数が急激に低下し（０．２３〜０．３９）、さらに炭素繊維を増やしても摩擦係数はそれほど変化しない。一方炭素繊維だけを用いた場合は比摩耗量が大きく（７．２×１０^-8）、ＳｉＣ繊維の混合量を増やしていくことで比摩耗量は指数関数的に大きく減少していく。これらのことから少なくとも炭素繊維の混合割合を２０％以上にすることで摩擦係数は大きく低下し、また少なくともＳｉＣ繊維の混合量を１０％以上にすることでＳｉＣ繊維を全く混合しない場合に比べて比摩耗量が大きく減少することがわかった。
【００２２】
図９は本発明にかかる滑り軸受を用いて構成したポンプ６０の一例を示す概略断面図である。同図に示すポンプ６０は、ポンプケーシング６１内にポンプ軸６３を収納するとともにポンプ軸６３の下端に羽根車６５を取り付け、ポンプ軸６３のポンプケーシング６１から上部に突出した部分を図示しない駆動手段によって回転駆動して羽根車６５を回転し、ポンプケーシング６１の吸込口６７から吐出口６９に向けて水を揚水していくものである。そしてポンプ軸６３を支持する滑り軸受７１，７３として本発明にかかる滑り軸受を用いている。これら滑り軸受７１，７３は揚水する水によって水潤滑される水潤滑軸受であり、運転開始時には滑り軸受７１，７３を潤滑する水は供給されていないが、本発明の滑り軸受７１，７３は摩擦係数が小さいので発熱量が少なく、割れ等の問題が発生しない。
【００２３】
以上本発明の実施形態を説明したが、本発明は上記実施形態に限定されるものではなく、特許請求の範囲、及び明細書と図面に記載された技術的思想の範囲内において種々の変形が可能である。なお直接明細書及び図面に記載がない何れの形状や構造や材質であっても、本願発明の作用・効果を奏する以上、本願発明の技術的思想の範囲内である。例えば上記実施形態では滑り軸受を適用する回転機械としてポンプを示したが、タービン、コンプレッサー、ブロワ等の他の各種回転機械にも適用できる。
【００２４】
【発明の効果】
以上詳細に説明したように本発明によれば、炭化ケイ素（ＳｉＣ）繊維と炭素繊維とをより合わせてなる複合糸を用いたので、耐摺動性と耐摩耗性と靭性と耐食性が高く且つ低摩擦係数を有する滑り軸受が得られ、またこの滑り軸受は低摩擦係数なのでこれを回転機械に用いて好適であり、特にポンプに用いた場合は無注水起動が容易に行える。
【図面の簡単な説明】
【図１】二次元の織物等を示す要部拡大図である。
【図２】三次元の織物等を示す要部拡大図である。
【図３】織物と編物と組紐とフィラメントワインディングの例を示す要部拡大図である。
【図４】 複合糸３０の製造装置を示す図である。
【図５】 複合糸３０の要部拡大図である。
【図６】 複合糸３０を平織りして作製した織物３５を示す図である。
【図７】織物３５を円筒状に巻き回した成形品４０を示す図である。
【図８】ＣＶＩ装置５０によって成形品４０にＣＶＩ処理を行う方法を示す図である。
【図９】本発明の滑り軸受７１，７３を適用したポンプ６０の一例を示す図である。
【符号の説明】
１０ アクリル繊維
１１ ボビン
１３ 熱硬化装置
１５ 炭化装置
１６ 炭素繊維
１７ 黒鉛化装置
１９ 加熱装置
２１ 安定化装置
２３ 焼結装置
２４ ＳｉＣ繊維
２５ 表面処理装置
２７ サイジング処理装置
３０ 複合糸
３９ ボビン
３５ 織物
４０ 成形品
５０ ＣＶＩ装置
５１ ヒータ
５３ 容器
５５ 成形品収納室
５７ 反応ガス入口
５９ 反応ガス出口
６０ ポンプ
６１ ポンプケーシング
６３ ポンプ軸
６５ 羽根車
６７ 吸込口
６９ 吐出口
７１，７３ 軸受[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the slip bearing and rotary machine that can be lowered and the friction coefficient has sliding resistance and abrasion resistance.
[0002]
[Prior art]
Conventionally, in a rotary machine such as a centrifugal pump, a sliding bearing may be used to hold a rotary body such as a pump shaft with respect to a stationary body such as a pump casing. As a material for this type of plain bearing, a rubber water-lubricated bearing is often used because of its simplicity. However, rubber water-lubricated bearings are subject to wear when foreign matter enters during operation. Also, since lubricating water must be supplied at the start of operation, it cannot be used as a type of plain bearing that is lubricated with water that is pumped after starting operation without water injection.
[0003]
On the other hand, high-hardness materials such as ceramics may be used in order to start water-free injection and increase corrosion resistance and wear resistance in water. However, this type of material has low toughness and is easy to crack, such as sliding bearings. It was difficult to handle as a structural part.
[0004]
In order to increase toughness, there are structural parts such as sliding bearings formed by molding ceramic fibers, but even in that case, the ceramic material has a high coefficient of friction, so it cracks due to repeated heating and cooling during sliding. There was a risk of occurrence.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of the above points and its object is able to increase the sliding resistance and abrasion resistance, high toughness, yet coefficient of friction to be Ru the slip bearing and rotary machines low It is to provide.
[0006]
[Means for Solving the Problems]
In the present invention, by blending carbon fiber with the ceramic fiber, the ceramic properties (hard to wear but large friction coefficient) and carbon properties (wear but small friction coefficient) are taken in a well-balanced state to obtain a predetermined hardness. In addition to obtaining slidability, the coefficient of friction was reduced and the toughness was improved by using fibers.
[0007]
That is, the invention according to claim 1 of the present application is a combination of silicon carbide (SiC) fibers gathered with continuous single fibers and carbon fibers gathered with continuous single fibers, and these silicon carbide (SiC) fibers and the entire carbon fibers. 10-80% by volume mixing ratio of silicon carbide (SiC) fibers to a composite yarn formed by 20 to 90% by volume mixing ratio of the carbon fiber, and processed woven, knitted, braid, or filament winding, further reaction A slip produced by using a fiber reinforced structure made of a fiber reinforced ceramic (CFCC) configured by filling silicon carbide (SiC) into the voids using a gas (CH ₃ SiCl ₃ —H ₂ ). It is a bearing.
In order to obtain a yarn, it is desirable that both silicon carbide (SiC) fibers and carbon fibers are a collection of continuous single fibers. Here, continuous single fiber is the smallest unit of fiber material, it is a basic unit formed by stretching or twisting, and it is not used alone, but gathers and has enough strength and flexibility Used as a thread with
[0008]
Fiber-reinforced structure using textiles, there is toughness, cracking hardly occurs. Since especially high fracture toughness, a possibility is eliminated that lacks bite foreign matters in Rukoto using fiber-reinforced structure of this the sliding bearing.
[0009]
On the other hand, when the gap is filled with ceramic, it becomes a fiber reinforced ceramic (CFCC: Continuous Fiber Ceramic Composite), and when the gap is filled (impregnated) with metal, it becomes a metal matrix fiber reinforced material (MMCs). When any material is filled, the wear resistance is improved, but when the ceramic is filled, the wear resistance is most improved . Hand metals corrode, but the ceramic does not corrode.
[0010]
Woven fabrics, knitted fabrics, and braids include two-dimensional ones such as plain weaves that are woven in a flat shape, and three-dimensional ones that are woven three-dimensionally. As a two-dimensional one, for example, as shown in FIG. 1, there is one in which the yarn 100 is woven only in a planar shape (XY direction). As a three-dimensional one, for example, as shown in FIG. 2 (a), the yarn 100 is woven in the X, Y, and Z-axis directions, and when it is cylindrical, for example, as shown in FIG. 2 (b) Some weave 100 in a circumferential-axis-radial direction. Further, for example, as shown in FIG. 3A, the woven fabric is formed by weaving warp yarns 101 and weft yarns 103 by a shuttle 105 or the like, and the knitted fabric is made of yarn 107 by knitting machine 109 as shown in FIG. 3B, for example. For example, as shown in FIG. 3C, the braid is formed by combining the yarns 111 in a string shape. Further, for example, as shown in FIG. 3D, filament winding forms a predetermined shape by winding a composite spun yarn 115 having a resin previously attached to the surface thereof around a mandrel 120 while being pressed by a pressure roller 117. To do.
[0011]
When a cylindrical bearing is configured using a two-dimensional fabric or the like, a flat fabric or the like is wound into a cylindrical shape a plurality of times to configure the bearing, so that heat conduction generated inside is radial. It becomes easier to transmit in the circumferential direction. For this reason, heat cannot be effectively transmitted to the outside. On the other hand, when a cylindrical bearing is constructed using a three-dimensional fabric or the like, the heat generated inside is conducted in the radial direction in the same way as in the circumferential direction, so that heat can be transferred to the outside easily. Is preferable.
[0012]
As a method for obtaining a fiber reinforced ceramic by impregnating a ceramic into a void of a composite spun yarn processed into a woven fabric, a knitted fabric, a braid, or a filament winding, CVI (Chemical Vapor Infiltration), CVD (Chemical Vapor Deposition), RS ( Reaction Sintering), Directed Oxidation (Lanxide) Process, PIP (Polymer Infiltration and Pyrolysis), MI (Melt Infiltration), Sol-Gel Techniques, HIP (Hot Isostatic Processing) There are various conventional ceramic filling methods such as the method. Silicon carbide (SiC 3 ) is used as the ceramic material.
[0015]
Sliding bearing of this may be used as a bearing of various rotating machines of the rotary shaft, sliding resistance, so excellent and low coefficient of friction and wear resistance, it is suitable for use for example in water-lubricated bearings. In particular, even if this sliding bearing is used for a sliding bearing for a rotary machine such as a pump having a structure in which it starts to lubricate with water pumped by itself after starting operation without water injection, water lubrication is started due to a low friction coefficient. The amount of heat generated by sliding until the end is small, and cracking does not occur and it can be used.
[0016]
The invention according to claim 2 of the present application is a rotating machine in which the sliding bearing according to claim 1 is incorporated.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
4 to 8 are views showing an example of a procedure for producing a water-lubricated bearing using the present invention. FIG. 4 is a view showing an apparatus for manufacturing the composite yarn 30. In order to manufacture the composite yarn 30 as shown in the figure, first, the acrylic fiber (PAN, polyacrylonitrile) 10 is pulled out from the bobbin 11 and cured by heating to 200 to 300 ° C. with a thermosetting device 13, and then carbonized. Carbonization is performed with high heat in the apparatus 15, and graphitization is performed with high heat in the graphitization apparatus 17 to obtain a desired carbon fiber 16. On the other hand, the SiC raw material 18 is stretched into a filament shape, fired by the heating device 19, then subjected to stabilization treatment by the stabilization device 21, and further sintered by the sintering device 23, thereby obtaining a desired SiC fiber 24. Then, the carbon fiber 16 and the SiC fiber 24, which are combined at an arbitrary ratio, are passed through a silane solvent by the surface treatment device 25 to make the epoxy resin easy to attach, and then the epoxy resin is removed by the sizing treatment device 27. After adhering, it is wound around the bobbin 29. The adhered epoxy resin is volatilized by heating during the process of processing the following fabric and the like.
[0018]
FIG. 5 is an enlarged view of a main part of the composite yarn 30 manufactured as described above. As shown in the figure, the composite yarn 30 is formed by intertwining carbon fibers 16 and SiC fibers 24. In this embodiment, the diameter of the composite yarn 30 is about 200 μm.
[0019]
In this embodiment, the composite yarn 30 produced as described above is plain-woven as shown in FIG. 6 to form a two-dimensional fabric 35, which is wound into a cylindrical shape as shown in FIG. The molded product 40 having the shape of Next, as shown in FIG. 8, the molded product 40 is stored in a molded product storage chamber 55 of the CVI device 50. Here, the CVI apparatus 50 is provided with a ring-shaped molded product storage chamber 55 by surrounding the outer periphery of a cylindrical heater 51 with a graphite container 53, and the heater 51 heats (heats) the molded product storage chamber 55. The reaction gas (CH ₃ SiCl ₃ —H ₂ ) is introduced from the reaction gas inlet 57 provided on the outer periphery of the container 53 while the temperature is 1400 ° C. The gas is discharged from the gas outlet 59. As a result, SiC is deposited on the surface of the molded product 40, and the voids of the molded product 40 are filled with SiC, so that a fiber-reinforced ceramic (CFCC) plain bearing is completed as a fiber-reinforced structure.
[0020]
Table 1 shown below is a table showing measurement results obtained by measuring various mechanical properties when the ratio of the SiC fiber and the carbon fiber of the cylindrical slide bearing manufactured as described above is changed.
[Table 1]

[0021]
In Table 1, the ratio of the fiber combining the SiC fiber and the carbon fiber with respect to the ceramic (base material: SiC) filled in the gap is made constant at 40% (base material 60%), and then the SiC fiber and the carbon fiber are mixed. Various mechanical properties in each case were measured by changing the ratio (volume%). As a result, when only SiC fiber is used as the fiber, the friction coefficient is large (0.73 to 0.55), and if only a small amount (20%) of carbon fiber is mixed with this SiC fiber, the friction coefficient rapidly decreases. (0.23 to 0.39) Further, the coefficient of friction does not change so much even if the carbon fiber is increased. On the other hand, when only the carbon fiber is used, the specific wear amount is large (7.2 × 10 ⁻⁸ ), and the specific wear amount greatly decreases exponentially by increasing the mixing amount of the SiC fiber. From these facts, at least the mixing ratio of carbon fibers is 20% or more, the friction coefficient is greatly reduced, and at least the mixing amount of SiC fibers is 10% or more compared with the case where no SiC fibers are mixed at all. It was found that the specific wear amount was greatly reduced.
[0022]
FIG. 9 is a schematic cross-sectional view showing an example of a pump 60 configured using the sliding bearing according to the present invention. The pump 60 shown in the figure accommodates a pump shaft 63 in a pump casing 61, an impeller 65 is attached to the lower end of the pump shaft 63, and a portion of the pump shaft 63 that protrudes upward from the pump casing 61 is not shown. And the impeller 65 is rotated to pump water from the suction port 67 of the pump casing 61 toward the discharge port 69. The sliding bearings according to the present invention are used as the sliding bearings 71 and 73 that support the pump shaft 63. These sliding bearings 71 and 73 are water-lubricated bearings that are water-lubricated by the pumped water, and water that lubricates the sliding bearings 71 and 73 is not supplied at the start of operation. Since the coefficient is small, the amount of heat generation is small, and problems such as cracking do not occur.
[0023]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. Note that any shape, structure, or material not directly described in the specification and drawings is within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are exhibited. For example, in the above embodiment, the pump is shown as a rotating machine to which a sliding bearing is applied. However, the present invention can also be applied to various other rotating machines such as a turbine, a compressor, and a blower.
[0024]
【The invention's effect】
As described above in detail, according to the present invention, since a composite yarn composed of silicon carbide (SiC) fibers and carbon fibers is used, the sliding resistance, wear resistance, toughness and corrosion resistance are high and A sliding bearing having a low friction coefficient can be obtained, and since this sliding bearing has a low friction coefficient, it is suitable for use in a rotary machine, and particularly when used in a pump, waterless start-up can be easily performed.
[Brief description of the drawings]
FIG. 1 is an enlarged view of a main part showing a two-dimensional fabric or the like.
FIG. 2 is an enlarged view of a main part showing a three-dimensional fabric or the like.
FIG. 3 is an enlarged view of a main part illustrating an example of a woven fabric, a knitted fabric, a braid, and a filament winding.
FIG. 4 is a view showing an apparatus for producing a composite yarn 30.
5 is an enlarged view of a main part of the composite yarn 30. FIG.
FIG. 6 is a view showing a woven fabric 35 produced by plain weaving a composite yarn 30. FIG.
FIG. 7 is a view showing a molded product 40 in which a woven fabric 35 is wound into a cylindrical shape.
FIG. 8 is a diagram showing a method of performing CVI processing on a molded product 40 by a CVI device 50.
FIG. 9 is a view showing an example of a pump 60 to which the plain bearings 71 and 73 of the present invention are applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Acrylic fiber 11 Bobbin 13 Thermosetting device 15 Carbonization device 16 Carbon fiber 17 Graphitization device 19 Heating device 21 Stabilization device 23 Sintering device 24 SiC fiber 25 Surface treatment device 27 Sizing treatment device 30 Composite yarn 39 Bobbin 35 Fabric 40 Molding Product 50 CVI device 51 Heater 53 Container 55 Molded product storage chamber 57 Reaction gas inlet 59 Reaction gas outlet 60 Pump 61 Pump casing 63 Pump shaft 65 Impeller 67 Suction port 69 Discharge port 71, 73 Bearing

Claims (2)

The silicon carbide (SiC) fibers gathered together with the continuous single fibers and the carbon fibers gathered with the continuous single fibers are combined, and the mixing ratio of the silicon carbide (SiC) fibers and the silicon carbide (SiC) fibers with respect to the whole carbon fibers is determined. 10-80% by volume, the composite yarn formed by 20 to 90% by volume mixing ratio of the carbon fiber, woven fabric, knitted fabric, braid, or processed into filament winding, further reaction gas (CH ₃ SiCl ₃ -H ₂₎ sliding bearings, characterized in that produced by using the fiber-reinforced structure composed of silicon carbide in a gap therebetween (SiC) fiber-reinforced ceramic constructed by filling the (CFCC) using.   A rotary machine comprising the slide bearing according to claim 1 incorporated therein.

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