JP2706987B2 - Ceramic member having cylindrical portion and method of grinding the cylindrical portion - Google Patents
Ceramic member having cylindrical portion and method of grinding the cylindrical portionInfo
- Publication number
- JP2706987B2 JP2706987B2 JP1186649A JP18664989A JP2706987B2 JP 2706987 B2 JP2706987 B2 JP 2706987B2 JP 1186649 A JP1186649 A JP 1186649A JP 18664989 A JP18664989 A JP 18664989A JP 2706987 B2 JP2706987 B2 JP 2706987B2
- Authority
- JP
- Japan
- Prior art keywords
- cylindrical portion
- grinding
- grinding wheel
- axis
- ceramic member
- 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.)
- Expired - Fee Related
Links
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は長尺の円筒部を有するセラミック製機械構造
部材及びその円筒部の研削方法に関し、特に、高い曲げ
強度を必要とするセラミック製部材と、それを製造する
ために砥石車で研削する方法の改良に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic mechanical structural member having a long cylindrical portion and a method for grinding the cylindrical portion, and in particular, a ceramic member requiring high bending strength. And an improvement in the method of grinding with a grinding wheel to produce the same.
〔従来の技術及び発明が解決しようとする課題〕 長尺の円筒部分を有して、その部分が高負荷を受ける
部材は、多くの産業用機械において用いられている。例
えば、内燃機関の吸排気用のきのこ形バルブは、燃焼室
に面する傘状の部分と、バルブガイドの中を高速で往復
運動する長尺円筒状のステム部からなっている。[Problems to be Solved by the Related Art and the Invention] A member having a long cylindrical portion, which is subjected to a high load, is used in many industrial machines. For example, a mushroom-shaped valve for intake and exhaust of an internal combustion engine includes an umbrella-shaped portion facing a combustion chamber and a long cylindrical stem portion that reciprocates at a high speed in a valve guide.
このようなバルブは高い強度と耐摩耗性を必要とする
ので、従来は金属で作られていた。しかし、近年になっ
てバルブの軽量化のために、バルブをセラミック製のも
のとすることが試みられるようになってきた。Because such valves require high strength and wear resistance, they have traditionally been made of metal. However, in recent years, attempts have been made to make the valve ceramic.
一方、上述の円筒部分の表面加工は、一般に砥石車に
よる研削によって行われているが、その方法を第４図と
第５図に概略的に示す（第５図は第４図のＢ−Ｂ線断面
図）。すなわち、ワーク１と砥石車２を互いに平行な軸
線回りで互いに逆回りで回転させながら、砥石車２又は
ワーク１を軸方向に移動させてワーク１の軸部分３の円
筒研削を行っていた。On the other hand, the surface processing of the above-mentioned cylindrical portion is generally performed by grinding with a grinding wheel, and the method is schematically shown in FIGS. 4 and 5 (FIG. 5 is BB of FIG. 4). Line sectional view). That is, the cylindrical grinding of the shaft portion 3 of the work 1 is performed by moving the grind wheel 2 or the work 1 in the axial direction while rotating the work 1 and the grinding wheel 2 in opposite directions about an axis parallel to each other.
しかし、この方法によれば、軸部分３の表面に、軸に
直交する研削痕、あるいは軸に対して90度に近い角度の
らせん状の研削痕が形成される。そのような研削痕は、
加工中に、あるいは完成品として部材が作動する際に、
クラックの起点となる可能性が大きく、そのために、曲
げ応力が加わったときに部材が破壊してしまうという問
題があった。すなわち、曲げ強度を低下させる原因にな
っていた。However, according to this method, a grinding mark perpendicular to the axis or a spiral grinding mark at an angle close to 90 degrees with respect to the axis is formed on the surface of the shaft portion 3. Such grinding marks are
During processing, or when the part operates as a finished product,
There is a large possibility that the member becomes a starting point of a crack, and there is a problem that the member is broken when a bending stress is applied. That is, it has caused a decrease in bending strength.
この問題を解決するために、特開昭63−216661号にお
いて、ワークの回転軸線に対して砥石車の回転軸線を２
つの回転軸線を直角に結ぶ線分回りに角度θだけ傾け、
ワーク周速ｖ、砥石車周速Ｖ及びワークのトラバース速
度ａについて、特定の式を満たす条件で円筒研削を行う
方法が提案されている。それによれば、ワークに、回転
軸線に対して30度以下の傾きをもつ研削痕が形成される
ので、前述のような、軸にほぼ直交する研削痕が形成さ
れる場合よりも、部材の曲げ強度が向上する。In order to solve this problem, Japanese Patent Application Laid-Open No. 63-216661 discloses a method in which the rotation axis of a grinding wheel is two
Tilted by an angle θ around a line connecting the two rotation axes at right angles,
A method has been proposed in which cylindrical grinding is performed under conditions satisfying a specific expression for a work peripheral speed v, a grinding wheel peripheral speed V, and a work traverse speed a. According to this, since a grinding mark having an inclination of 30 degrees or less with respect to the rotation axis is formed on the work, the bending of the member is more difficult than the case where the grinding mark substantially perpendicular to the axis is formed as described above. Strength is improved.
しかるに、このような方法で研削してもなお、前述の
ようなセラミック製バルブに適用した場合には、満足で
きる曲げ強度が得られないことがわかった。また、条件
式を満足する周速とトラバース速度を決める作業も煩雑
である。However, it has been found that satisfactory bending strength cannot be obtained when applied to a ceramic valve as described above even after grinding by such a method. Also, the work of determining the peripheral speed and the traverse speed that satisfies the conditional expression is complicated.
従って、本発明の目的は、従来の研削方法を用いた場
合よりも高い曲げ強度を備えた円筒部を有するセラミッ
ク製部材、及びその円筒部の研削方法を提供することで
ある。SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a ceramic member having a cylindrical portion having a higher bending strength than when a conventional grinding method is used, and a method of grinding the cylindrical portion.
上記目的に鑑みて、本発明は、真っ直ぐな円筒部を有
し、前記円筒部の表面の研削痕が、前記円筒部の軸に実
質的に平行に直線状に形成されていることを特徴とする
セラミックス製部材を抵抗する。In view of the above object, the present invention has a straight cylindrical portion, and grinding marks on the surface of the cylindrical portion are formed in a straight line substantially parallel to the axis of the cylindrical portion. To resist ceramic members.
また、本発明のセラミック製部材の円筒部の研削方法
は、前記部材を静止させた状態で、円筒部の軸線に対し
て垂直な回転軸を有する砥石車を回転させながら、円筒
部の軸方向に砥石車を移動して円筒部を研削する工程
と、砥石車を部材から離した状態にして、部材を軸回り
に一定の角度だけ回転する工程とを交互に繰り返すこと
によって、円筒部表面に研削痕が軸方向に平行に形成さ
れるようにすることを特徴とする。Further, the method of grinding a cylindrical portion of a ceramic member of the present invention, in a state where the member is stationary, while rotating a grinding wheel having a rotation axis perpendicular to the axis of the cylindrical portion, the axial direction of the cylindrical portion The process of moving the grinding wheel to grind the cylindrical portion and the process of rotating the member around the axis by a fixed angle alternately by repeating the process of grinding the cylindrical portion away from the member, It is characterized in that grinding marks are formed parallel to the axial direction.
以下、本発明を詳細に説明する。 Hereinafter, the present invention will be described in detail.
第１図と第２図において、１はセラミック製部材であ
り、２は砥石車である。この例では部材１は、内燃機関
の吸排気バルブである。1 and 2, reference numeral 1 denotes a ceramic member, and reference numeral 2 denotes a grinding wheel. In this example, the member 1 is an intake / exhaust valve of an internal combustion engine.
第１図に示すように真っ直ぐな円筒状のステム部３を
精密な円筒形に研削するために、部材１をセンター４、
４間に固定して保持する。部材１の軸Ｏに対して砥石車
２の軸Ｐは垂直である。部材１を静止したまま、砥石車
２を回転させながら、部材１の軸方向へトラバース移動
させて数回往復し、ステム部３の表面を研削する。砥石
車２を１往復する毎に約0.1mm下げていき、最終的に削
りしろを1mm程度にする場合、ステム部３の寸法精度は1
0μ程度必要である。砥石車２の周速は1600〜1800m/分
とし、砥石車２の目の粗さは＃200〜1000の範囲とする
のがよい。また目の粗さの大きなものから小さいもの
へ、砥石車を数回取り換えて、複数段階で研削してもよ
い。In order to grind a straight cylindrical stem portion 3 into a precise cylindrical shape as shown in FIG.
It is fixed and held between the four. The axis P of the grinding wheel 2 is perpendicular to the axis O of the member 1. While the member 1 is stationary, the grindstone 2 is traversed and reciprocated several times in the axial direction while rotating the grinding wheel 2 to grind the surface of the stem portion 3. When the grinding wheel 2 is lowered by about 0.1 mm each time the wheel 2 reciprocates, and finally the cutting margin is about 1 mm, the dimensional accuracy of the stem 3 is 1
About 0μ is required. The peripheral speed of the grinding wheel 2 is preferably 1600 to 1800 m / min, and the roughness of the grinding wheel 2 is preferably in the range of # 200 to 1000. In addition, the grinding wheel may be replaced several times from the one having a large coarseness to the one having a small coarseness, and the grinding may be performed in a plurality of stages.
このようにして、ステム部３の円周のうちの１ケ所
を、軸方向に線状に研削し終えたら、砥石車２を部材１
からいったん離し、部材１を軸Ｏの回りに一定の角度、
例えば５度だけ回転させる。これによって、前に研削し
た部分に隣接する部分を研削する準備がなされる。In this way, once one portion of the circumference of the stem portion 3 has been ground linearly in the axial direction, the grinding wheel 2 is moved to the member 1.
Once, the member 1 is fixed at a certain angle around the axis O,
For example, rotate by 5 degrees. This prepares to grind the portion adjacent to the previously grinded portion.
次いで再び、砥石車２の回転とトラバース移動によっ
て、ステム部３の表面を研削する。Next, the surface of the stem portion 3 is ground again by the rotation and the traverse movement of the grinding wheel 2.
以上の工程を繰り返すことによって、ステム部３の全
周を研削する。これによって、ステム部３の表面に、軸
方向に平行な研削痕が形成されるが、最終的な面粗度は
0.8S〜3.5Sとするのがよい。By repeating the above steps, the entire periphery of the stem portion 3 is ground. As a result, grinding marks parallel to the axial direction are formed on the surface of the stem portion 3, but the final surface roughness is
0.8 S to 3.5 S is preferable.
3.5Sよりも粗くすると、相手摺動部材に傷をつけてし
まい、一方、0.8Sよりも細かくしても摺動特性の著しい
向上は得られず、強度も従来の方法により場合との差が
小さくなり、製造コストが高くなるだけである。If it is coarser than 3.5S, the mating sliding member will be damaged.On the other hand, if it is finer than 0.8S, no remarkable improvement in sliding characteristics will be obtained, and the strength will differ from the conventional method. It only makes it smaller and increases manufacturing costs.
第３図に示すように、砥石車２の円周研削面を湾曲し
た凹面にしてもよい。このようにすることによって、ス
テム部３と砥石車２との接触面が大きくなり、円筒部全
周の研削が完了するまでの時間を短くすることができ
る。凹面の曲率半径はステム部３の曲率半径にできるだ
け近い方が好ましい。As shown in FIG. 3, the circumferential grinding surface of the grinding wheel 2 may be a curved concave surface. By doing so, the contact surface between the stem portion 3 and the grinding wheel 2 becomes large, and the time until the grinding of the entire circumference of the cylindrical portion is completed can be shortened. The radius of curvature of the concave surface is preferably as close as possible to the radius of curvature of the stem portion 3.
長尺な部材に対する曲げ応力は、部材の軸に垂直な方
向に作用するが、本発明の方法によって研削された円筒
部を有するセラミック製部材は、円筒表面の砥石車によ
る研削痕が、部材の軸方向に平行に形成されているの
で、研削痕が残っても部材本来の強度がほとんど低下し
ない。The bending stress on a long member acts in a direction perpendicular to the axis of the member. However, a ceramic member having a cylindrical portion ground by the method of the present invention has a grinding mark on the cylindrical surface caused by a grinding wheel on the member. Since it is formed parallel to the axial direction, the original strength of the member hardly decreases even if grinding marks remain.
実施例１ 窒化ケイ素を射出成形して、全長135mm、傘部分の径2
6mm、ステム径8.0mmのバルブ素材を用意した。次いで、
ステムの円周全体を、本発明の方法によって、レジンボ
ンドダイヤモンド製の砥石車（径100mm、円周面はフラ
ット）で、砥石車周速1600m/分、砥石車往復ストローク
100mm、ワークのステップ回転角度10度の条件で0.5mm研
削した。Example 1 Silicon nitride was injection-molded to a total length of 135 mm and an umbrella diameter of 2
6mm, 8.0mm stem diameter valve material was prepared. Then
Using the method of the present invention, the entire circumference of the stem is ground with a resin-bonded diamond grinding wheel (diameter 100 mm, the circumferential surface is flat) at a grinding wheel peripheral speed of 1600 m / min.
Grinding was performed 0.5 mm under the conditions of 100 mm and the step rotation angle of the work was 10 degrees.
その結果、ステム軸に平行な研削痕が形成され、研削
痕の方向と垂直な方向の面粗度は3Sとなった。As a result, grinding marks parallel to the stem axis were formed, and the surface roughness in a direction perpendicular to the direction of the grinding marks was 3S.
比較例１ 実施例１と同様にして、バルブ素材を用意した後、ス
テムの軸線と砥石車の回転軸線を平行にし、両者を互い
に逆回転させながら砥石車を軸方向に移動させて、ステ
ム円周全体を0.5mm研削した。この場合、砥石車の材質
と寸法は実施例１と同じであり、砥石車周速は1600m/
分、ステム周速2.0m/分、砥石車のトラバース速度10m/
分とした。Comparative Example 1 In the same manner as in Example 1, after preparing the valve material, the axis of the stem was made parallel to the rotation axis of the grinding wheel, and the grinding wheel was moved in the axial direction while rotating the two wheels in the opposite directions to form a stem circle. The entire circumference was ground by 0.5 mm. In this case, the material and dimensions of the grinding wheel are the same as in the first embodiment, and the grinding wheel peripheral speed is 1600 m /
Min, stem peripheral speed 2.0m / min, traverse speed of grinding wheel 10m / min
Minutes.
この結果、ステム軸にほぼ垂直な研削痕が形成され、
研削痕の方向と垂直な方向の面粗度は3Sとなった。As a result, grinding marks almost perpendicular to the stem axis are formed,
The surface roughness in the direction perpendicular to the direction of the grinding marks was 3S.
比較例２ 実施例１と同様にして、バルブ素材を用意した後、ス
テムの軸線に対して砥石車の回転軸線を、２つの軸線を
直角に結ぶ線分回りに角度60度だけ傾け、両者を互いに
逆回転させながら砥石車を軸方向に移動させて、ステム
円周全体を0.5mm研削した。この場合、砥石車の材質と
寸法は実施例１と同じであり、砥石車周速は1600m/分、
ステム周速2m/分、砥石車のトラバース速度10mm/分とし
た。Comparative Example 2 In the same manner as in Example 1, after preparing the valve material, the rotation axis of the grinding wheel was inclined at an angle of 60 degrees around a line connecting the two axes at right angles to the axis of the stem. The grinding wheel was moved in the axial direction while rotating in opposite directions to grind the entire stem circumference by 0.5 mm. In this case, the material and dimensions of the grinding wheel are the same as in Example 1, the peripheral speed of the grinding wheel is 1600 m / min,
The stem peripheral speed was 2 m / min, and the traverse speed of the grinding wheel was 10 mm / min.
この結果、ステム軸に対して29.2度の傾きをもつ研削
痕が形成され、研削痕の方向と垂直な方向の面粗度は3S
となった。As a result, grinding marks having an inclination of 29.2 degrees with respect to the stem axis were formed, and the surface roughness in a direction perpendicular to the direction of the grinding marks was 3S.
It became.
以上、実施例１、比較例１、比較例２によって製造さ
れたバルブのステム部分の曲げ強度を、３点曲げ強度試
験によって測定した。支点長さ30mm、クロスヘッドスピ
ード0.5mm/minとして、各々５回測定した平均で、実施
例１の場合、90kg/mm2で破壊したのに対して、比較例１
は76kg/mm2、比較例２では83g/mm2で破壊し、本発明の
方法で製造されたバルブの曲げ強度の高さが確認され
た。As described above, the bending strength of the stem portion of the valve manufactured according to Example 1, Comparative Example 1, and Comparative Example 2 was measured by a three-point bending strength test. Fulcrum length 30 mm, as a cross-head speed 0.5 mm / min, the average measured each 5 times, in the case of Example 1, with respect to that breakdown by 90 kg / mm 2, Comparative Example 1
Fractured at 76 kg / mm 2 , and in Comparative Example 2 at 83 g / mm 2 , the bending strength of the valve manufactured by the method of the present invention was confirmed.
以上説明した通り、本発明の方法によって研削された
円筒部を有するセラミック製部材は、円筒表面の研削痕
が部材の軸方向に平行に形成されている。長尺な部材に
対する曲げ応力は、部材の軸に垂直な方向に作用する
が、軸に平行な研削痕は曲げ応力を低下させない。従っ
て、本発明のセラミック製部材は、従来の研削方法によ
り研削したものと比較して、曲げ強度が著しく向上して
いる。As described above, in the ceramic member having the cylindrical portion ground by the method of the present invention, the grinding marks on the cylindrical surface are formed parallel to the axial direction of the member. The bending stress on a long member acts in a direction perpendicular to the axis of the member, but grinding marks parallel to the axis do not reduce the bending stress. Therefore, the bending strength of the ceramic member of the present invention is remarkably improved as compared with that obtained by grinding by the conventional grinding method.
第１図は本発明の方法の一実施例を示す正面図であり、 第２図は第１図のＡ−Ａ線縦断面図であり、 第３図は本発明の方法の他の実施例を示す縦断面図であ
り、 第４図は従来の方法を示す正面図であり、 第５図は第４図のＢ−Ｂ線縦断面図である。 １……セラミック製部材 ２……砥石車 ３……ステム部（円筒部） ４……センターFIG. 1 is a front view showing an embodiment of the method of the present invention, FIG. 2 is a longitudinal sectional view taken along line AA of FIG. 1, and FIG. 3 is another embodiment of the method of the present invention. FIG. 4 is a front view showing a conventional method, and FIG. 5 is a vertical sectional view taken along the line BB of FIG. 1 Ceramic member 2 Grinding wheel 3 Stem (cylindrical part) 4 Center
Claims (5)
材において、前記円筒部の表面の研削痕が、前記円筒部
の軸に実質的に平行に直線状に形成されていることを特
徴とするセラミック製部材。1. A ceramic member having a straight cylindrical portion, wherein grinding marks on the surface of the cylindrical portion are formed in a straight line substantially parallel to an axis of the cylindrical portion. Parts.
ク製部材において、前記円筒部の表面の面粗度が0.8S〜
3.5Sであることを特徴とするセラミック製部材。2. A ceramic member having a cylindrical portion according to claim 1, wherein the surface of said cylindrical portion has a surface roughness of 0.8S or less.
A ceramic member characterized by 3.5S.
ク製部材において、前記部材は内燃機関用の吸排気用セ
ラミック製バルブであることを特徴とする部材。3. The ceramic member having a cylindrical portion according to claim 1, wherein said member is a ceramic intake / exhaust valve for an internal combustion engine.
表面研削方法であって、前記部材を静止させた状態で、
円筒部の軸線に対して垂直な回転軸を有する砥石車を回
転させながら、円筒部の軸方向に砥石車を移動して円筒
部を研削する工程と、砥石車を部材から離した状態にし
て、部材を軸回りに一定の角度だけ回転する工程とを交
互に繰り返すことによって、円筒部表面に研削痕が軸方
向に平行に形成されるようにすることを特徴とする方
法。4. A method for grinding a surface of a ceramic member having a long cylindrical portion, wherein said member is stationary.
While rotating a grinding wheel having a rotation axis perpendicular to the axis of the cylindrical portion, a step of moving the grinding wheel in the axial direction of the cylindrical portion to grind the cylindrical portion, and keeping the grinding wheel away from the member And a step of rotating the member by a fixed angle around the axis alternately so that grinding marks are formed on the surface of the cylindrical portion in parallel with the axial direction.
車の円周状研削面を湾曲した凹面にしたことを特徴とす
る方法。5. The method according to claim 4, wherein the circumferential grinding surface of the grinding wheel is a curved concave surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1186649A JP2706987B2 (en) | 1989-07-19 | 1989-07-19 | Ceramic member having cylindrical portion and method of grinding the cylindrical portion |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1186649A JP2706987B2 (en) | 1989-07-19 | 1989-07-19 | Ceramic member having cylindrical portion and method of grinding the cylindrical portion |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0355154A JPH0355154A (en) | 1991-03-08 |
| JP2706987B2 true JP2706987B2 (en) | 1998-01-28 |
Family
ID=16192274
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1186649A Expired - Fee Related JP2706987B2 (en) | 1989-07-19 | 1989-07-19 | Ceramic member having cylindrical portion and method of grinding the cylindrical portion |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2706987B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102005014108A1 (en) * | 2005-03-22 | 2006-09-28 | Schott Ag | Method for grinding a workpiece made from glass, glass-ceramic or ceramic comprises clamping the workpiece to a holder, driving the workpiece about an axis of rotation and processing the workpiece using a grinding tool |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57163047A (en) * | 1981-03-30 | 1982-10-07 | Akira Washida | Machining method of ring |
-
1989
- 1989-07-19 JP JP1186649A patent/JP2706987B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0355154A (en) | 1991-03-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |