JPH05272541A - Ceramic bearing - Google Patents
Ceramic bearingInfo
- Publication number
- JPH05272541A JPH05272541A JP4071715A JP7171592A JPH05272541A JP H05272541 A JPH05272541 A JP H05272541A JP 4071715 A JP4071715 A JP 4071715A JP 7171592 A JP7171592 A JP 7171592A JP H05272541 A JPH05272541 A JP H05272541A
- Authority
- JP
- Japan
- Prior art keywords
- friction coefficient
- bearing
- ceramic
- ceramic material
- crack
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000000919 ceramic Substances 0.000 title claims abstract description 23
- 229910010293 ceramic material Inorganic materials 0.000 claims abstract description 18
- 229910052581 Si3N4 Inorganic materials 0.000 abstract description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 abstract description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 abstract 1
- 229910052593 corundum Inorganic materials 0.000 abstract 1
- 238000005336 cracking Methods 0.000 abstract 1
- 229910001845 yogo sapphire Inorganic materials 0.000 abstract 1
- 239000000463 material Substances 0.000 description 13
- 238000001513 hot isostatic pressing Methods 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000012886 linear function Methods 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Landscapes
- Rolling Contact Bearings (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、無潤滑状態で使用さ
れるセラミック軸受に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic bearing used without lubrication.
【０００２】[0002]
【従来の技術】機械的要素の重要な一部である軸受に対
する性能要求は年々過酷になってきており、たとえば、
工作機械主軸などにおける高速回転性能やガスタービン
などにおける高温耐熱性、さらに特殊環境下での耐腐食
性など種々の性能の向上が要求されている。これらの要
求に対して、軸受素材の面からはセラミックスが従来の
軸受鋼に比べて優れており、セラミック軸受が広く使用
されるようになってきている。2. Description of the Related Art Performance requirements for bearings, which are an important part of mechanical elements, are becoming severer year after year.
Various performance improvements such as high-speed rotation performance in machine tool spindles, high-temperature heat resistance in gas turbines, and corrosion resistance in special environments are required. In view of these requirements, ceramics are superior to conventional bearing steels in terms of bearing materials, and ceramic bearings have been widely used.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、セラミ
ックスは、上述のような優れた性能を持ち合わせている
反面、脆性材料であるがために信頼性が低く、その性能
が十分生かされていないのが現状である。とくに、無潤
滑状態で使用されるセラミック軸受は、摩擦係数が大き
いため、摺動面に亀裂が発生し、これが破壊の起因とな
るという問題がある。However, while ceramics have the above-mentioned excellent performances, they are brittle materials, so that their reliability is low and their performances are not fully utilized. Is. In particular, a ceramic bearing used in a non-lubricated state has a large friction coefficient, so that there is a problem that a crack is generated on a sliding surface, which causes destruction.
【０００４】この発明の目的は、上記の問題を解決し、
無潤滑状態でも亀裂の発生を抑制できる信頼性の高いセ
ラミック軸受を提供することにある。The object of the present invention is to solve the above problems,
An object of the present invention is to provide a highly reliable ceramic bearing that can suppress the occurrence of cracks even in a non-lubricated state.
【０００５】[0005]
【課題を解決するための手段】この発明によるセラミッ
ク軸受は、無潤滑状態で使用されるセラミック軸受であ
って、軸受の接触面圧および軸受を構成するセラミック
ス材料の摩擦係数が、セラミック材料表面の先在亀裂長
さから求められた接触面圧および摩擦係数の安全領域内
にあることを特徴とするものである。The ceramic bearing according to the present invention is a ceramic bearing used in a non-lubricated state, and the contact surface pressure of the bearing and the coefficient of friction of the ceramic material forming the bearing are different from those of the surface of the ceramic material. It is characterized in that the contact surface pressure and the friction coefficient obtained from the preexisting crack length are within the safe region.
【０００６】[0006]
【作用】軸受を構成するセラミックス材料における亀裂
（クラック）の伝播は、破壊力学における応力拡大係数
で論じられる。すなわち、引張り型亀裂開口モードにお
ける先在亀裂（材料の表面に最初から存在する微小な亀
裂）の応力拡大係数が破壊靭性値を越えたときに亀裂が
成長し破壊に至る。破壊靭性値は材料によって定まる値
であり、応力拡大係数はセラミックス材料表面の先在亀
裂長さ、軸受の接触面圧および軸受を構成するセラミッ
クス材料の摩擦係数の関数になる。したがって、先在亀
裂長さをパラメータとして、応力拡大係数が破壊靭性値
と等しくなるときの摩擦係数と接触面圧の関係がこれら
の直交座標上で１つの臨界曲線として求められる。そし
て、この臨界曲線の一方の側（接触面圧および摩擦係数
が小さい側）が安全領域、反対側（接触面圧および摩擦
係数が大きい側）が危険領域となり、接触面圧および摩
擦係数が安全領域になるようにすることにより、亀裂の
成長が抑制され、亀裂による脆性破壊が抑制される。The propagation of cracks in the ceramic material forming the bearing is discussed by the stress intensity factor in fracture mechanics. That is, when the stress intensity factor of a preexisting crack (a minute crack existing on the surface of the material from the beginning) in the tensile crack opening mode exceeds the fracture toughness value, the crack grows and fractures. The fracture toughness value is a value determined by the material, and the stress intensity factor is a function of the pre-existing crack length on the surface of the ceramic material, the contact surface pressure of the bearing, and the friction coefficient of the ceramic material forming the bearing. Therefore, using the pre-existing crack length as a parameter, the relationship between the friction coefficient and the contact surface pressure when the stress intensity factor becomes equal to the fracture toughness value is obtained as one critical curve on these orthogonal coordinates. One side of this critical curve (the side where the contact surface pressure and the friction coefficient is small) is the safe area, and the other side (the side where the contact surface pressure and the friction coefficient is large) is the danger area, and the contact surface pressure and the friction coefficient are safe. By setting the region, the crack growth is suppressed and brittle fracture due to the crack is suppressed.
【０００７】[0007]
【実施例】以下、図面を参照して、この発明の実施例に
ついて説明する。Embodiments of the present invention will be described below with reference to the drawings.
【０００８】図１はセラミック・スラスト玉軸受の例を
示しており、２つの軌道輪(11)(12)およびこれらの間に
配置された複数の玉(13)はセラミックス、たとえば、Ｙ
2 Ｏ3 とＡｌ2 Ｏ3 を助剤としてＨＩＰ（熱間等方圧プ
レス法）で製造された窒化けい素セラミックスよりな
る。FIG. 1 shows an example of a ceramic thrust ball bearing. Two bearing rings (11) (12) and a plurality of balls (13) arranged between them are made of ceramics such as Y.
It consists of silicon nitride ceramics manufactured by HIP (hot isostatic pressing) with 2 O 3 and Al 2 O 3 as auxiliary agents.
【０００９】この軸受は、接触面圧およびこれを構成す
るセラミックス材料の摩擦係数がセラミックス材料表面
の先在亀裂長さから求められた安全領域内にあるような
条件で使用される。次に、この安全領域の求め方につい
て説明する。This bearing is used under such conditions that the contact surface pressure and the coefficient of friction of the ceramic material forming the contact surface are within the safety region determined from the pre-existing crack length on the surface of the ceramic material. Next, how to obtain this safety area will be described.
【００１０】上述のように、軸受を構成するセラミック
ス材料における亀裂の伝播は破壊力学における応力拡大
係数で論じられ、引張り型亀裂開口モードにおける先在
亀裂の応力拡大係数ＫI が材料の破壊靭性値ＫICを越え
たときに破壊に至る。先在亀裂長さｃの応力拡大係数Ｋ
I は、次の式(1) で表わされる。As described above, the crack propagation in the ceramic material constituting the bearing is discussed by the stress intensity factor in fracture mechanics, and the stress intensity factor K I of the pre-existing crack in the tensile crack opening mode is the fracture toughness value of the material. When it exceeds K IC , it will be destroyed. Stress intensity factor K of pre-existing crack length c
I is expressed by the following equation (1).
【００１１】ＫI ＝Ｙσ（πｃ）0.5 …(1) ここで、Ｙは亀裂形状に依存する定数、σは無限遠方で
作用する一様応力である（図２参照）。図２において、
(14)は軸受を構成するセラミックス材料、(14a) はその
表面、(15)は材料表面(14a) の先在亀裂である。また、
材料表面(14a)上の転がり方向をＸ軸、材料表面(14a)
上のＸ軸と垂直な方向をＹ軸、Ｘ軸およびＹ軸と垂直な
材料(14)の内部方向をＺ軸とした。K I = Yσ (πc) 0.5 (1) Here, Y is a constant depending on the crack shape, and σ is a uniform stress acting at infinity (see FIG. 2). In FIG.
(14) is a ceramic material constituting the bearing, (14a) is its surface, and (15) is a pre-existing crack on the material surface (14a). Also,
Rolling direction on material surface (14a) is X-axis, material surface (14a)
The direction perpendicular to the upper X axis was taken as the Y axis, and the internal direction of the material (14) perpendicular to the X axis and the Y axis was taken as the Z axis.
【００１２】重ね合わせの原理から、無限遠方で作用す
る一様応力σは亀裂まわりの応力に置き換えることがで
き、次の式(2) に示すように接触面圧ｐとこの接触面圧
で無次元化された最大主応力の最大値σO （μ）の積で
表わされる。From the principle of superposition, the uniform stress σ acting at infinity can be replaced by the stress around the crack, and as shown in the following equation (2), the contact surface pressure p and this contact surface pressure are It is expressed by the product of the maximum value σ O (μ) of the dimensioned maximum principal stress.
【００１３】σ＝ｐσO （μ） …(2) σO （μ）は摩擦係数μをパラメータとしており、ハミ
ルトンの応力解析式から次の式(3) で表わすことができ
る。Σ = pσ O (μ) (2) σ O (μ) has a friction coefficient μ as a parameter, and can be expressed by the following equation (3) from the Hamiltonian stress analysis equation.
【００１４】 σO （μ）＝μ（４＋ν）π／８＋（１−２ν）／３ …(3) ここで、νはポアソン比であり、これは材料定数である
ので、図３に示すように、σO （μ）は摩擦係数μの一
次関数となる。なお、図３には、窒化けい素セラミック
スの場合の摩擦係数μと最大主応力の最大値との関係を
示している。Σ O (μ) = μ (4 + ν) π / 8 + (1-2ν) / 3 (3) Here, ν is the Poisson's ratio, which is a material constant, and therefore, as shown in FIG. In addition, σ O (μ) is a linear function of the friction coefficient μ. Note that FIG. 3 shows the relationship between the friction coefficient μ and the maximum value of the maximum principal stress in the case of silicon nitride ceramics.
【００１５】亀裂伝播の境界条件は応力拡大係数ＫI が
材料の破壊靭性値ＫICと等しくなることであり、したが
って、これは次の式(4) で表わされる。The boundary condition for crack propagation is that the stress intensity factor K I is equal to the fracture toughness value K IC of the material, which is therefore expressed by the following equation (4).
【００１６】 ＫI ＝ＫIC＝ＹｐσO （μ）（πｃ）0.5 …(4) このときのｐが臨界面圧となり、これは次の式(5) のよ
うに表わされる。K I = K IC = Ypσ O (μ) (πc) 0.5 (4) At this time, p is the critical surface pressure, which is expressed by the following equation (5).
【００１７】 ｐ＝ＫIC／ＹσO （μ）（πｃ）0.5 …(5) 式(5) より、先在亀裂長さｃをパラメータとして、臨界
面圧ｐを摩擦係数μで表わすことができる。このように
して表わした摩擦係数μと臨界面圧ｐとの関係が図４に
示されている。同図において、横軸は摩擦係数μ、縦軸
は接触面圧ｐを表わしており、曲線Ｐ1 、Ｐ2 およびＰ
3 は先在亀裂長さｃが０．１、０．５および１．０μｍ
の場合の臨界面圧を示している。そして、各曲線Ｐ1 、
Ｐ2 およびＰ3 より図の左下側（接触面圧および摩擦係
数の小さい側）が安全領域、反対の各曲線Ｐ1 、Ｐ2 お
よびＰ3 より図の右上側（接触面圧および摩擦係数の大
きい側）が危険領域となっている。P = K IC / Yσ O (μ) (πc) 0.5 (5) From equation (5), the critical surface pressure p can be expressed by the friction coefficient μ with the preexisting crack length c as a parameter. .. The relationship between the friction coefficient μ and the critical surface pressure p thus expressed is shown in FIG. In the figure, the horizontal axis represents the friction coefficient μ, and the vertical axis represents the contact surface pressure p. The curves P 1 , P 2 and P
3 has pre-existing crack length c of 0.1, 0.5 and 1.0 μm
The critical surface pressure in the case of is shown. Then, each curve P 1 ,
The lower left side of Fig than P 2 and P 3 (contact surface pressure and smaller in coefficient of friction) is safe area, in FIG from the curves P 1, P 2 and P 3 on the opposite upper right side (the contact surface of the pressure and friction coefficient The larger side) is the dangerous area.
【００１８】軸受に使用されるセラミックス材料が決ま
れば、先在亀裂長さがわかり、先在亀裂長さがわかれ
ば、図４のような関係から安全領域がわかり、摩擦係数
および接触面圧がこの安全領域内になるような条件で軸
受が使用される。なお、セラミックス材料の先在亀裂長
さは、その表面粗さで代用することもできる。If the ceramic material used for the bearing is determined, the pre-existing crack length can be known, and if the pre-existing crack length is known, the safety region can be known from the relationship shown in FIG. 4, and the friction coefficient and contact surface pressure can be The bearing is used under the condition that it is within the safe area. The surface crack can be used as a substitute for the pre-existing crack length of the ceramic material.
【００１９】上記の軸受は、上記のように求められた安
全領域内で使用されるので、摩擦係数および接触面圧が
臨界条件に達することがなく、したがって、亀裂の生成
が抑制される。Since the above-mentioned bearing is used within the safety region obtained as described above, the friction coefficient and the contact surface pressure do not reach the critical conditions, and therefore the generation of cracks is suppressed.
【００２０】[0020]
【発明の効果】この発明のセラミック軸受によれば、上
述のように、亀裂の生成を抑制して、亀裂による脆性破
壊を抑制することができ、したがって、無潤滑状態での
セラミック軸受の信頼性を向上させることができる。As described above, according to the ceramic bearing of the present invention, the generation of cracks can be suppressed and brittle fracture due to the cracks can be suppressed, and therefore the reliability of the ceramic bearing in a non-lubricated state can be improved. Can be improved.
【図１】この発明の実施例を示すセラミック・スラスト
玉軸受の縦断面図である。FIG. 1 is a vertical sectional view of a ceramic thrust ball bearing showing an embodiment of the present invention.
【図２】セラミックス材料の表面部分および先在亀裂を
示す説明図である。FIG. 2 is an explanatory view showing a surface portion and a preexisting crack of a ceramic material.
【図３】摩擦係数と最大主応力の最大値との関係を示す
グラフである。FIG. 3 is a graph showing a relationship between a friction coefficient and a maximum value of maximum principal stress.
【図４】摩擦係数と接触面圧との臨界条件を示すグラフ
である。FIG. 4 is a graph showing a critical condition of a friction coefficient and a contact surface pressure.
(1)(2) 軌道輪 (3) 玉 (4) セラミックス材料 (4a) セラミックス材料表面 (5) 先在亀裂 (1) (2) Bearing ring (3) Ball (4) Ceramics material (4a) Ceramics material surface (5) Preexisting crack
Claims (1)
あって、軸受の接触面圧および軸受を構成するセラミッ
クス材料の摩擦係数が、セラミック材料表面の先在亀裂
長さから求められた接触面圧および摩擦係数の安全領域
内にあることを特徴とするセラミック軸受。1. A ceramic bearing used in a non-lubricated state, wherein the contact surface pressure of the bearing and the friction coefficient of the ceramic material forming the bearing are determined from the length of the preexisting crack on the surface of the ceramic material. Ceramic bearings characterized in that they are within the safe range of pressure and coefficient of friction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07171592A JP3353152B2 (en) | 1992-03-27 | 1992-03-27 | Ceramic bearings |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07171592A JP3353152B2 (en) | 1992-03-27 | 1992-03-27 | Ceramic bearings |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05272541A true JPH05272541A (en) | 1993-10-19 |
| JP3353152B2 JP3353152B2 (en) | 2002-12-03 |
Family
ID=13468506
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP07171592A Expired - Fee Related JP3353152B2 (en) | 1992-03-27 | 1992-03-27 | Ceramic bearings |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3353152B2 (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61258141A (en) * | 1985-05-11 | 1986-11-15 | Kawasaki Steel Corp | Fatigue precrack detecting method for fracture touchness test piece |
| JPS6256620A (en) * | 1985-09-05 | 1987-03-12 | Nippon Seiko Kk | rolling bearing |
| JPS62153729A (en) * | 1985-12-27 | 1987-07-08 | Saginomiya Seisakusho Inc | Fracture toughness test method |
| JPS638532A (en) * | 1986-06-30 | 1988-01-14 | Kawasaki Steel Corp | Fatigue pre-crack formation device for fracture toughness test pieces |
| JPS6491031A (en) * | 1987-10-02 | 1989-04-10 | Japan Tobacco Inc | Method and apparatus for nondestructive inspection of roller bearing |
| JPH01184439A (en) * | 1988-01-19 | 1989-07-24 | Nippon Steel Corp | Foreknowing method for generation of crack of product made of jointing ceramics and metal |
-
1992
- 1992-03-27 JP JP07171592A patent/JP3353152B2/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61258141A (en) * | 1985-05-11 | 1986-11-15 | Kawasaki Steel Corp | Fatigue precrack detecting method for fracture touchness test piece |
| JPS6256620A (en) * | 1985-09-05 | 1987-03-12 | Nippon Seiko Kk | rolling bearing |
| JPS62153729A (en) * | 1985-12-27 | 1987-07-08 | Saginomiya Seisakusho Inc | Fracture toughness test method |
| JPS638532A (en) * | 1986-06-30 | 1988-01-14 | Kawasaki Steel Corp | Fatigue pre-crack formation device for fracture toughness test pieces |
| JPS6491031A (en) * | 1987-10-02 | 1989-04-10 | Japan Tobacco Inc | Method and apparatus for nondestructive inspection of roller bearing |
| JPH01184439A (en) * | 1988-01-19 | 1989-07-24 | Nippon Steel Corp | Foreknowing method for generation of crack of product made of jointing ceramics and metal |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3353152B2 (en) | 2002-12-03 |
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|---|---|---|---|
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