JP2009018366A

JP2009018366A - Method of grinding convex surface

Info

Publication number: JP2009018366A
Application number: JP2007181893A
Authority: JP
Inventors: Yasuhisa Tomita; 泰央冨田
Original assignee: Nikon Corp
Current assignee: Nikon Corp
Priority date: 2007-07-11
Filing date: 2007-07-11
Publication date: 2009-01-29

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of grinding a convex surface capable of sufficiently providing rigidity to a tool, reducing the wear of a grinding wheel, improving working efficiency and grinding accuracy, and stably manufacturing products. <P>SOLUTION: A work W3 is supported on a work support means 57a movably in the Z-axis direction and rotatably in the C-axis direction. A cup-like tool T3 having an outer diameter larger a predetermined amount than the outer diameter of the non-ground part of the work is attached to the end of the tool support means 67 installed on a rotary table 53 movable in the X-axis direction. The end surface outer end of the tool T3 is aligned with the rotating center of the rotary table 53. The inclination angle of the tool support means 67 to the Z-axis in an X-Z plane is changed within a predetermined range. The work support means 57a is rotated and slid in the Z-axis direction, the tool support means 67 is rotated and slid in the X-axis direction, and the rotary table 53 is rotated. The tool and the work are brought into point contact with each other on the B-axis, and the work is ground along the point-contraposition convex surface formed on the end surface of the work. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、金型、レンズ等のワークの端面の点対偶凸曲面を研削する凸曲面研削方法に関する。 The present invention relates to a convex curved surface grinding method for grinding a point-to-even convex curved surface of an end face of a workpiece such as a mold or a lens.

光学素子は成形により形成され量産されている。レンズ成形金型は、超精密切削法及び研削加工法を用いて所望する形状精度と表面粗さに加工される。非球面レンズ生産におけるプレス成形金型は、成形システムの高安定・低コスト化の要望から、レンズに相対する金型面数の低減から、分離金型（筒型とＲ２凸型）を一体にした形状の金型にシフトしている。特に、非球面部を中心部に有する点対偶凸曲面を成形できる光学素子用の成形金型が望まれている。 Optical elements are formed by mass production. The lens molding die is processed to a desired shape accuracy and surface roughness using an ultra-precise cutting method and a grinding method. For press molding dies in aspherical lens production, separation molds (cylindrical mold and R2 convex mold) are integrated in order to reduce the number of mold faces facing the lens in order to achieve high stability and low cost of the molding system. It has shifted to the mold of the shape. In particular, there is a demand for a molding die for an optical element that can mold a point-to-even convex curved surface having an aspherical surface at the center.

レンズ成形金型の研削加工方法としては、例えば、特許文献１の研削加工方法が提案されている。 As a grinding method of the lens molding die, for example, the grinding method of Patent Document 1 has been proposed.

他方、従来において、Ｒ２凸型の研削には、二軸パラレル方式の点対偶凸曲面研削を行う図４に示す研削装置１０が使用されている。図４において、符号１1は定盤であり、定盤１1上に設けられたＺ軸方向スライドテーブル１２に、Ｚ軸方向に沿ったＣ軸１３の回りに例えば矢印１４の方向に回転自在であるワーク回転軸１５にワークＷ１を支持し、定盤１1上に設けられたＸ軸方向スライドテーブル１６に設けられたＸ軸方向に沿ったＡ軸１７の回りに例えば矢印１８の方向に回転自在であるツール回転軸１９に算盤玉形状のツールＴ１を支持してなる。さらに、この研削装置によれば、ツールＴ１の径が小さくかつ小径のツールシャフト２０をツール回転軸１９より張り出して取り付けたシャンク２１にチャックする構成であり、径が１０ｍｍφ〜２０ｍｍφのワークＷ１を対象としている。 On the other hand, conventionally, for the R2 convex grinding, a grinding apparatus 10 shown in FIG. 4 that performs point-to-even convex curved surface grinding of a biaxial parallel system is used. In FIG. 4, reference numeral 11 denotes a surface plate, which can be freely rotated around the C axis 13 along the Z-axis direction, for example, in the direction of an arrow 14 on a Z-axis direction slide table 12 provided on the surface plate 11. The workpiece W1 is supported on the workpiece rotating shaft 15, and is rotatable in the direction of the arrow 18 around the A axis 17 along the X axis direction provided on the X axis direction slide table 16 provided on the surface plate 11. A tool rotation shaft 19 supports an abacus ball-shaped tool T1. Furthermore, according to this grinding apparatus, the tool shaft 20 having a small tool T1 diameter and a small diameter is chucked to the shank 21 that is mounted so as to protrude from the tool rotating shaft 19, and the workpiece W1 having a diameter of 10 mmφ to 20 mmφ is targeted. It is said.

この研削方法は、ワーク回転軸１５とツール回転軸１９とをそれぞれ回転させ、ワークＷ１の先端面をツールＴ１の周面に当接し、Ｚ軸方向スライドテーブル１６のＺ軸方向スライドとＸ軸方向スライドテーブル１２のＸ軸方向スライドとを相対的に動作させることにより、ツールＴ１によりワークＷ１の端面に精密仕上げ切削加工により形成された点対偶凸曲面に対して精密に倣うようにツールＴ１を平面→凹Ｒ面→非球面と連続移動して非球面レンズ形状に研削し、点対偶凸曲面に対して研削するものである。 In this grinding method, the workpiece rotation shaft 15 and the tool rotation shaft 19 are rotated, the tip surface of the workpiece W1 is brought into contact with the peripheral surface of the tool T1, and the Z-axis direction slide and the X-axis direction of the Z-axis direction slide table 16 are contacted. By relatively moving the slide table 12 with respect to the X-axis direction slide, the tool T1 is flattened so as to closely follow the point-to-even convex curved surface formed by precision finishing cutting on the end surface of the workpiece W1 by the tool T1. → Concave R surface → Aspherical surface is continuously moved and ground to an aspherical lens shape, and then ground to a point-to-even convex curved surface.

この研削方法によれば、ツールＴ１の径が小さく算盤珠形状であり、かつ、ツールシャフトが小径で長く張り出しているので、砥石の摩耗時期が早くしかも不定期であり、砥石形状維持が困難であり、加工能率が低く、形状精度が１μｍ、および形状誤差が１μｍである。 According to this grinding method, the tool T1 has a small abacus bead shape, and the tool shaft has a small diameter and a long overhang. Therefore, the wear time of the grindstone is early and irregular, and it is difficult to maintain the grindstone shape. Yes, the machining efficiency is low, the shape accuracy is 1 μm, and the shape error is 1 μm.

図５（ａ）〜（ｄ）は、現在使用されている他の研削装置３０の研削行程図を示す。構成を図５（ａ）を参照して説明する。研削装置３０は、定盤（図示しない）上に設けられたＺ軸方向スライドテーブル３１に、Ｚ軸方向に沿ったＣ軸３２の回りに例えば矢印３３の方向に回転自在であるワーク回転軸３４にワークＷ２を支持し、定盤（図示しない）上に設けられたＸ軸方向スライドテーブル３５に設けられた回動テーブル３６上に、回転軸心３７がワーク回転軸３４の回転軸心３２を通るＸ−Ｚ平面内を旋回するツール回転軸３８を設け、該ツール回転軸３８にツールＴ２を支持してツールＴ２の先端面外端を回動テーブル３８の回転中心（Ｂ軸）３９に一致させてなる。さらに、この研削装置によれば、ツールＴ２が小径の円筒体でありかつ小径のツールシャフト４０をツール回転軸３８より張り出して取り付けたシャンク４１にチャックする構成であり、径が１０ｍｍφ〜２０ｍｍφのワークＷ２を対象としている。 FIGS. 5A to 5D show grinding stroke diagrams of another grinding apparatus 30 currently used. The configuration will be described with reference to FIG. The grinding device 30 is provided on a Z-axis direction slide table 31 provided on a surface plate (not shown). The workpiece rotation shaft 34 is rotatable around the C-axis 32 along the Z-axis direction, for example, in the direction of an arrow 33. The rotating shaft 37 supports the rotating shaft 32 of the workpiece rotating shaft 34 on the rotating table 36 provided on the X-axis direction slide table 35 provided on the surface plate (not shown). A tool rotation shaft 38 that swivels in the passing XZ plane is provided, the tool T2 is supported on the tool rotation shaft 38, and the outer end of the tip end surface of the tool T2 coincides with the rotation center (B axis) 39 of the rotary table 38. Let me. Further, according to this grinding apparatus, the tool T2 is a small-diameter cylindrical body, and the small-diameter tool shaft 40 is chucked to the shank 41 attached by protruding from the tool rotating shaft 38, and the workpiece has a diameter of 10 mmφ to 20 mmφ. Targeting W2.

この研削方法は、ワーク回転軸３２とツール回転軸３８とをそれぞれ回転させ、ワークＴ２の先端面をＢ軸３９に一致するツール３９の先端面に当接し、Ｚ軸方向スライドテーブル３１のＺ軸方向スライドとＸ軸方向スライドテーブル３５のＸ軸方向スライドと回動テーブル３６のＢ軸回動とを相対的に動作させることにより、図５（ａ）→（ｂ）→（ｃ）→（ｄ）のツール運行行程に示すように、ツールＴ２を平面→凹Ｒ面→非球面と連続移動し、ワークＷ２の端面に精密仕上げ切削加工された点対偶凸曲面に対して精密に倣うように、ツールＴ２を運行し、かつ、ツールＴ２の研削接点における両側の隙間角が等しくなるように保ち、非球面レンズ形状に研削し、点対偶凸曲面に対して研削するものである。 In this grinding method, the workpiece rotating shaft 32 and the tool rotating shaft 38 are rotated, the tip surface of the workpiece T2 is brought into contact with the tip surface of the tool 39 coinciding with the B axis 39, and the Z axis of the Z axis direction slide table 31 is contacted. 5 (a) → (b) → (c) → (d) by relatively moving the direction slide, the X axis direction slide of the X axis direction slide table 35 and the B axis rotation of the rotation table 36. As shown in the tool operation process of), the tool T2 is continuously moved from a flat surface to a concave R surface to an aspherical surface so as to closely follow the point-to-even convex curved surface that has been precisely finished on the end surface of the workpiece W2. The tool T2 is operated, and the gap angles on both sides of the grinding contact point of the tool T2 are kept equal to each other, ground to an aspheric lens shape, and ground to a point-to-even convex curved surface.

この研削方法によれば、図４の研削方法に比べ、砥石の摩耗時期と加工能率が多少改善され、形状精度が０．１μｍ、および形状誤差が０．０５μｍである研削が行える。 According to this grinding method, compared with the grinding method of FIG. 4, the grinding time and processing efficiency of the grindstone are somewhat improved, and grinding with a shape accuracy of 0.1 μm and a shape error of 0.05 μm can be performed.

上述したように、図５に示す研削装置３０は、図４に示す研削装置１０よりも優れているので、凸曲面研削方法の主流となっている。
特開２００２−３４６８９３号公報 As described above, the grinding apparatus 30 shown in FIG. 5 is superior to the grinding apparatus 10 shown in FIG.
JP 2002-346893 A

しかしながら、ワークの大径化が進むと共に、非球面形状精度のさらなる高精度化と加工能率の向上の要求に対して、図５に示す凸曲面研削方法では、ツールの剛性の不足と砥石形状の不安定により安定生産に限界を生じてきた。 However, as the workpiece diameter increases, the convex curved surface grinding method shown in FIG. 5 is insufficient for the rigidity of the tool and the shape of the grindstone. Instability has put a limit on stable production.

そこで、この発明は、ツールの剛性が十分に得られかつ砥石形状が安定し、砥石の摩耗が少なく、加工能率が高く、形状精度がさらに高く得られ、形状誤差がさらに小さくて安定生産できる凸曲面研削方法を提供することを課題とする。 Therefore, the present invention provides a convexity that provides sufficient tool rigidity and stable grinding wheel shape, less wear of the grinding wheel, high processing efficiency, higher shape accuracy, and smaller shape error and stable production. It is an object of the present invention to provide a curved surface grinding method.

かかる課題を達成するために、本発明は、Ｃ軸に回転自在のワーク支持手段にワークを支持し、Ｃ軸と直角方向のＢ軸に回転自在の回動テーブルに備えられたＢ軸に直角面内を回動自在のツール支持手段の先端に、外径が前記ワークの被研削部の外径よりも所要大きいカップ状のツールを取り付け、かつ、該ツールの先端面外端を前記回動テーブルの回転中心であるＢ軸に一致させ、前記ワーク支持手段と前記ツール支持手段に、それぞれ回転を与えると共に、Ｘ軸−Ｚ軸の二次元方向の相対的なスライドを与えることにより、前記回動テーブルの回転中心線上で前記ツールと前記ワークとを点接触させつつ前記ツールと前記ワークの相対的な向きを変えて、前記ワークの端面に形成された凸曲面に倣って研削することを特徴とする凸曲面研削方法。 In order to achieve this object, the present invention supports a workpiece on a workpiece support means that is rotatable about a C axis, and is perpendicular to the B axis provided on a rotary table that is rotatable about a B axis perpendicular to the C axis. A cup-shaped tool whose outer diameter is required to be larger than the outer diameter of the part to be ground of the workpiece is attached to the tip of the tool support means that can rotate in the plane, and the tip end outer end of the tool is rotated. The rotation is made to coincide with the B axis which is the rotation center of the table, and the workpiece support means and the tool support means are each rotated, and the relative slide in the two-dimensional direction of the X axis-Z axis is given. The tool and the workpiece are point-contacted on the rotation center line of the moving table, the relative orientation of the tool and the workpiece is changed, and grinding is performed following the convex curved surface formed on the end surface of the workpiece. Convex Curve Lab Method.

本発明によれば、ツールの剛性が十分に得られかつ砥石形状が安定し、砥石の摩耗が少なく、加工能率が高く、形状精度が従来よりもさらに高く得られ、形状誤差を従来よりも小さく抑えられ、安定生産できる。 According to the present invention, the rigidity of the tool is sufficiently obtained, the shape of the grindstone is stable, the wear of the grindstone is less, the processing efficiency is higher, the shape accuracy is higher than before, and the shape error is smaller than before. Suppressed and stable production is possible.

以下、本発明の実施の形態について図面を参照して説明する。
〔実施の形態１〕 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Embodiment 1]

図１（ａ）〜（ｄ）は、本発明の実施の形態にかかる研削装置５０の研削行程の平面図を示す。 Fig.1 (a)-(d) shows the top view of the grinding process of the grinding device 50 concerning embodiment of this invention.

図１（ａ）〜（ｄ）において、紙面（図面）の横方向がＸ軸、縦方向がＺ軸、紙面（図面）の横方向がＹ軸、回転中心線がＸ軸に沿う方向をＡ軸、回転中心線がＹ軸に沿う方向をＢ軸、及び、回転中心線がＺ軸に沿う方向をＣ軸と設定するものとする。 1A to 1D, the horizontal direction of the paper surface (drawing) is the X axis, the vertical direction is the Z axis, the horizontal direction of the paper surface (drawing) is the Y axis, and the rotation center line is the direction along the X axis. The direction in which the axis and the rotation center line are along the Y axis is set as the B axis, and the direction in which the rotation center line is along the Z axis is set as the C axis.

まず、構成を図１（ａ）を参照して説明する。研削装置５０は、定盤（図示しない）上にＺ軸方向スライドテーブル５１とＸ軸方向スライドテーブル５２とが設けられ、Ｘ軸方向スライドテーブル５２には回動テーブル５３が設けられ回動テーブル５３の回転中心がＢ軸５４となっている。 First, the configuration will be described with reference to FIG. The grinding device 50 is provided with a Z-axis direction slide table 51 and an X-axis direction slide table 52 on a surface plate (not shown), and the X-axis direction slide table 52 is provided with a rotation table 53. Is the B-axis 54.

Ｚ軸方向スライドテーブル５１上に第１の固定台５５が設けられ、この第１の固定台５５に軸受５６を介してワーク回転軸５７が設けられ、このワーク回転軸５７が第１のモータ５８により回転される構成であり、このワーク回転軸５７の先端にワーク支持手段５７ａが設けられた構成である。なお、Ｚ軸方向スライドテーブル５１とＸ軸方向スライドテーブル５２と回動テーブル５３の各駆動源は図示していない。 A first fixed base 55 is provided on the Z-axis direction slide table 51, and a work rotation shaft 57 is provided on the first fixed base 55 via a bearing 56, and the work rotation shaft 57 is a first motor 58. And a work support means 57 a is provided at the tip of the work rotation shaft 57. The drive sources for the Z-axis direction slide table 51, the X-axis direction slide table 52, and the rotation table 53 are not shown.

この構成により、ワーク回転軸５７は、Ｚ軸方向に沿ったＣ軸５９の回りに例えば矢印６０の方向に回転自在であり、かつ、Ｚ軸方向スライドテーブル５１によりＺ軸方向にスライド自在であり、軸先端には、詳細を図示していないが、ワークＷ３を支持するチャック機能を有している。 With this configuration, the workpiece rotation shaft 57 is rotatable around the C axis 59 along the Z axis direction, for example, in the direction of the arrow 60, and is slidable in the Z axis direction by the Z axis direction slide table 51. Although not shown in detail at the tip of the shaft, it has a chuck function for supporting the workpiece W3.

また、回動テーブル５３上に第２の固定台６１が設けられ、この第２の固定台６１に軸受６２を介してツール回転軸６３が設けられ、このツール回転軸６３が第２の固定台６１に設けられた第２のモータ６４により回転される構成である。ツール回転軸６３の軸心６５は、ワーク回転軸５７の軸心５９と同一の高さに設けられ、回動テーブル５３が回動すると、ワーク回転軸５７の軸心５９を通るＸ−Ｚ平面内に旋回される。 A second fixed base 61 is provided on the rotary table 53, and a tool rotation shaft 63 is provided on the second fixed base 61 via a bearing 62. The tool rotation shaft 63 is used as the second fixed base. The second motor 64 is provided with a second motor 64. The axis 65 of the tool rotation shaft 63 is provided at the same height as the axis 59 of the workpiece rotation shaft 57. When the rotation table 53 rotates, the XZ plane passes through the axis 59 of the workpiece rotation shaft 57. It is turned in.

この構成により、ツール回転軸６３は、第２のモータ６４により例えば矢印６６の方向に回転自在、Ｘ軸方向スライドテーブル５２によりＸ軸方向にスライド自在、回動テーブル５３によりワーク回転軸５７の軸心を通るＸ−Ｚ平面内に旋回自在であり、軸先端には、詳細を図示していないが、ツール（砥石）Ｔ３を支持している。 With this configuration, the tool rotation shaft 63 can be rotated in the direction of the arrow 66 by the second motor 64, for example, can be slid in the X-axis direction by the X-axis direction slide table 52, and the work rotation shaft 57 can be rotated by the rotation table 53. The tool can be swung in an XZ plane passing through the center, and a tool (grinding stone) T3 is supported at the tip of the shaft, although details are not shown.

第２の固定台６１は、回動テーブル５３上に二次元方向に位置調整可能・精密位置決め可能に設けられている（図示しない）。そして、ツールＴ３の先端面の中心を通るＸ−Ｚ平面と交差する端縁が回動テーブル５３の回転中心のＢ軸５４に一致するように、第２の固定台６１が回動テーブル５３上に位置決めされ、これにより、ツールＴ３の先端面の中心を通るＸ−Ｚ平面と交差する端縁が、回動テーブル５３の旋回とＸ軸方向スライドテーブル５２の移動を行っても、回動テーブル５３の回転中心のＢ軸に常に一致し、このＢ軸５４上にツールＴ３とワークＷ３を接触させて研削する。 The second fixed base 61 is provided on the rotating table 53 so that the position can be adjusted in the two-dimensional direction and the position can be precisely positioned (not shown). Then, the second fixed base 61 is placed on the rotary table 53 so that the edge intersecting the XZ plane passing through the center of the tip surface of the tool T3 coincides with the B axis 54 of the rotary center of the rotary table 53. Therefore, even if the edge that intersects the XZ plane passing through the center of the tip surface of the tool T3 performs the turning of the turning table 53 and the movement of the X-axis direction slide table 52, the turning table The tool T3 and the workpiece W3 are brought into contact with the B-axis 54 for grinding.

特に、この研削装置５０によれば、ワーク回転軸５７の先端に備えたワーク支持手段５７ａで例えば外径が３０ｍｍφ以上の大きなワークＷ３を着脱自在であると共に、ツール回転軸６３の先端にツール（砥石）Ｔ３を着脱自在に支持するツール支持手段として、この実施の形態では、フランジ６７を備え、このフランジ６７にはテーパ軸６８を備え、このテーパ軸６８をツール回転軸６３に設けられたテーパ孔に嵌合することにより、フランジ６７をワンタッチで着脱自在である。フランジ６７は、ツールＴ３を触れ回りしないように保持できるように適宜機構を備えているものとする（図示しない）。そして、このフランジ６７に、カップ状凹部の内径がワークＷ３の外径と略同等以上の大きさであることが好ましい。また、ツールＴ３は、外径が例えば３０ｍｍφのワークＷ３であるときに、外径がワークＷ３の外径の１．５倍〜２倍の大きさであることが好ましい。こうしたワークＷ３とカップ状のツールＴ３との寸法関係により、研削時における両者の干渉を避けることができる。この実施の形態では、カップ状のツールＴ３がツール支持手段６７のフランジ面に一体に固着されていて、ツールＴ３とツール支持手段６７とが一体に交換可能にツール回転軸６３に嵌着されている。 In particular, according to the grinding apparatus 50, a workpiece W3 having an outer diameter of 30 mmφ or more, for example, can be freely attached and detached by a workpiece support means 57a provided at the tip of the workpiece rotation shaft 57, and a tool ( In this embodiment, a flange 67 is provided as a tool supporting means for detachably supporting the grinding wheel T3. The flange 67 is provided with a taper shaft 68, and the taper shaft 68 is provided on the tool rotation shaft 63. By fitting into the hole, the flange 67 can be attached and detached with one touch. The flange 67 is appropriately provided with a mechanism (not shown) so that the tool T3 can be held without touching. In addition, it is preferable that the inner diameter of the cup-shaped concave portion of the flange 67 is approximately equal to or larger than the outer diameter of the workpiece W3. Further, when the tool T3 is a workpiece W3 having an outer diameter of, for example, 30 mmφ, the outer diameter is preferably 1.5 to 2 times the outer diameter of the workpiece W3. Due to the dimensional relationship between the workpiece W3 and the cup-shaped tool T3, interference between the workpiece W3 and the cup-shaped tool T3 can be avoided. In this embodiment, the cup-shaped tool T3 is integrally fixed to the flange surface of the tool support means 67, and the tool T3 and the tool support means 67 are fitted on the tool rotating shaft 63 so as to be interchangeable. Yes.

本発明の凸曲面研削方法は、上記構成の研削装置５０による研削方法であり、ワーク回転軸５７とツール回転軸６３とをそれぞれ回転させ、ワークＷ３の先端面を、Ｂ軸５４と一致するツールＴ３の先端面に当接し、Ｚ軸方向スライドテーブル５１のＺ軸方向スライドとＸ軸方向スライドテーブル５２のＸ軸方向スライドと回動テーブル５３のＢ軸回動とを相対的に動作させ、図２（ａ）→（ｂ）→（ｃ）→（ｄ）のツール運行行程（逆の行程でも良い）に示すように、ツールＴ３を、ワークＷ３の端面に精密仕上げ切削加工された点対偶凸曲面に対して、平面→凹Ｒ面→非球面と精密に倣うように連続運行する。 The convex curved surface grinding method of the present invention is a grinding method using the grinding device 50 having the above-described configuration, and rotates the workpiece rotating shaft 57 and the tool rotating shaft 63, respectively, so that the tip surface of the workpiece W3 coincides with the B axis 54. Abutting on the tip surface of T3, the Z-axis direction slide of the Z-axis direction slide table 51, the X-axis direction slide of the X-axis direction slide table 52, and the B-axis rotation of the rotation table 53 are relatively operated. 2 (a) → (b) → (c) → (d) As shown in the tool operation process (the reverse process is acceptable), the tool T3 is point-even evenly formed by precision finish cutting on the end face of the work W3. It operates continuously so as to closely follow the curved surface, that is, plane → concave R surface → aspheric surface.

その際、ツール回転軸６３のＺ軸に対する傾き角を可変し、前記ワークの端面に精密切削加工により形成された中央部に凸状非球面を有する凸曲面に倣うように、ツールＴ３をワークＷ３に対して相対的に運行し、好ましくは、ツールＴ３の刃の先端角を２分割する分割線６９の延長線がワークＷ３の被研磨点における曲率中心を通るように（研削接点における両側の隙間角が等しくなるように）保ち、点対偶凸曲面に対して研削する。 At that time, the tilt angle of the tool rotation shaft 63 with respect to the Z-axis is varied, and the tool T3 is moved to the workpiece W3 so as to follow a convex curved surface having a convex aspheric surface at the center formed by precision cutting on the end surface of the workpiece. Preferably, the extension line of the dividing line 69 that bisects the tip angle of the blade of the tool T3 passes through the center of curvature at the point to be polished of the workpiece W3 (the gap on both sides of the grinding contact). Grind against point-to-even convex curved surface.

これにより、研削時において、ツールＴ３の回転中心線とワークＷ３の回転中心線（Ｃ軸と一致する）との交差角が、ワークＷ３の円周部の平面を研磨する際には、６７．５°又はこれに近い角度になり（図１（ａ）参照）、ワークＷ３の円周部の平面から非球面部に移行する凹曲面部では曲率中心が小さくしかも非球面部の曲率中心とは反対側になるため、該交差角を６７．５°〜ｍａｘ９０°まで変化させ（図１（ｂ）参照）、研磨点がワークＷ３の非球面部に移ったら、再び６７．５°まで戻していく（図１（ｃ），（ｄ）参照）。 Thereby, during grinding, when the intersection angle between the rotation center line of the tool T3 and the rotation center line of the workpiece W3 (coincident with the C axis) polishes the plane of the circumferential portion of the workpiece W3, 67. The angle of curvature is 5 ° or close to this (see FIG. 1A), and the center of curvature is small in the concave curved surface portion that transitions from the plane of the circumferential portion of the workpiece W3 to the aspherical portion, and the curvature center of the aspherical portion is Since it is on the opposite side, the crossing angle is changed from 67.5 ° to max 90 ° (see FIG. 1B), and when the polishing point moves to the aspherical surface of the workpiece W3, it is returned to 67.5 ° again. (See FIGS. 1C and 1D).

この実施の形態のカップ状のツールＴ３は、刃先角が外周面に対して４５°又は４５°に近い鋭角であるので、研削時のツールＴ３の揺動を小さく抑えられるから、研削点の変動量に対するツール揺動量を小さく抑えられ、凹曲面部に対して滑らかな倣い研削ができる。 The cup-shaped tool T3 of this embodiment has a cutting edge angle of 45 ° or an acute angle close to 45 ° with respect to the outer peripheral surface, so that the swing of the tool T3 during grinding can be suppressed to a small level, and the fluctuation of the grinding point The amount of swinging of the tool with respect to the amount can be suppressed small, and smooth copying grinding can be performed on the concave curved surface portion.

本発明では、ツール回転軸６３のＸ−Ｚ平面内のＺ軸に対する傾き角を４５°〜９０°の範囲内に抑えて可変すれば、ツールＴ３がワークＷ３を深く研削したり他分に対して干渉する研削を生じない。 In the present invention, if the tilt angle of the tool rotation shaft 63 with respect to the Z axis in the XZ plane is varied within a range of 45 ° to 90 °, the tool T3 can grind the workpiece W3 deeply or otherwise Does not cause interference grinding.

すなわち、この凸曲面研削方法は、Ｚ軸方向に移動自在かつＺ軸方向に沿うＣ軸に回転自在のワーク回転軸５７にワークＷ３を支持し、一方、カップ状凹部の内径がワークの外径より大きいカップ状のツールＴ３をＸ軸方向に移動自在な回動テーブル５３に備えるツール回転軸６３の先端に取り付け、ツールＴ３の先端面外端を回動テーブル５３の回転中心に一致させ、ツール回転軸６３のＸ−Ｚ平面内のＺ軸に対する傾き角を４５°〜９０°の範囲内として可変し、ワーク回転軸５７に回転とＺ軸方向スライドとを与え、ツール回転軸６３に回転とＸ軸方向スライドとＢ軸回動とを与え、Ｂ軸上にツールＴ３とワークＷ３を点接触させてワークＷ３の端面に形成された点対偶凸曲面に倣って研削する。 That is, in this convex curved surface grinding method, the workpiece W3 is supported on the workpiece rotating shaft 57 that is movable in the Z-axis direction and rotatable in the C-axis along the Z-axis direction, while the inner diameter of the cup-shaped recess is the outer diameter of the workpiece. A larger cup-shaped tool T3 is attached to the tip of the tool rotation shaft 63 provided in the rotation table 53 that is movable in the X-axis direction, and the outer end of the tip surface of the tool T3 is made to coincide with the rotation center of the rotation table 53. The tilt angle of the rotary shaft 63 with respect to the Z axis in the XZ plane is varied within a range of 45 ° to 90 °, rotation and Z-axis direction slide are given to the work rotary shaft 57, and the tool rotary shaft 63 is rotated. An X-axis direction slide and a B-axis rotation are given, and the tool T3 and the workpiece W3 are brought into point contact on the B-axis, and grinding is performed following a point-to-even convex curved surface formed on the end surface of the workpiece W3.

要するに、この凸曲面研削方法は、ワーク支持手段５７ａとツール支持手段６７に、それぞれ回転を与えると共に、Ｘ軸−Ｚ軸の二次元方向の相対的なスライドを与えることにより、回動テーブル５３の回転中心線上（Ｂ軸上）でツールＴ３とワークＷ３とを点接触させつつツールＴ３とワークＷ３の相対的な向きを変えて、ワークＷ３の端面に形成された凸曲面に倣って研削するものである。 In short, in this convex curved surface grinding method, the workpiece support means 57a and the tool support means 67 are each rotated, and the relative slide in the two-dimensional direction of the X-axis and Z-axis is given, so The tool T3 and the workpiece W3 are point-contacted on the rotation center line (on the B axis), and the relative orientation of the tool T3 and the workpiece W3 is changed to perform grinding according to the convex curved surface formed on the end surface of the workpiece W3. It is.

この研削方法によれば、図４、図５の研削方法に比べ、ツールＴ３が図５のツールに比べ、頗る大きいので、砥石の摩耗が少なく、加工能率が高く、ワークＷ３の形状精度が０．０５μｍ、および形状誤差が０．０２μｍである研削が行えようになった。

According to this grinding method, the tool T3 is much larger than the grinding method of FIG. 5 compared to the grinding method of FIGS. 4 and 5, so that the wear of the grindstone is small, the processing efficiency is high, and the shape accuracy of the workpiece W3 is 0. Grinding with .05 μm and shape error of 0.02 μm can be performed.

この実施の形態によれば、ツール径を飛躍的に大きくしたときの加工現象の解明から、上記のような加工精度が得られる凸曲面研削方法を開発したもので、カップ状凹部の内径がワークの外径より大きいカップ状のツールを採用したことでツールの剛性が十分に得られかつ砥石形状が安定し、ツールの摩耗が少なくなり、求める高い加工能率が得られ、ワークの形状精度・形状安定性をさらに高く得られ、形状誤差がさらに小さく抑えられ、安定生産でき、デジタルカメラの高画素化に寄与できる。 According to this embodiment, a convex curve grinding method has been developed to obtain the above machining accuracy from the elucidation of the machining phenomenon when the tool diameter is dramatically increased. By adopting a cup-shaped tool larger than the outer diameter of the tool, the rigidity of the tool can be obtained sufficiently, the grinding wheel shape is stable, the wear of the tool is reduced, the required high machining efficiency is obtained, and the shape accuracy and shape of the workpiece Higher stability can be obtained, shape errors can be further reduced, stable production can be achieved, and contribution to higher pixel count of digital cameras.

この実施の形態によれば、前記ツール支持手段のツール支持部の外径が前記カップ状のツールの外径にほぼ等しい大きさであるので、ツール支持手段をカップ状のツールの大きさに対応して選択でき、ツール回転軸に簡単に装着でき、ツール支持手段がツール回転軸からは長く張り出さないので、ツールの剛性を一層十分に得られ、一層高い加工精度が得られ、デジタルカメラの高画素化に寄与できる。 According to this embodiment, since the outer diameter of the tool support portion of the tool support means is approximately equal to the outer diameter of the cup-shaped tool, the tool support means corresponds to the size of the cup-shaped tool. Since the tool support means does not protrude from the tool rotation axis for a long time, the rigidity of the tool can be obtained more sufficiently and higher processing accuracy can be obtained. This can contribute to higher pixels.

この実施の形態によれば、ツール回転軸の先端に着脱可能に備えたツール支持手段にカップ状のツールを支持して研削するので、ツール交換が容易であり、装置の稼働率が向上する。 According to this embodiment, since the cup-shaped tool is supported and ground by the tool support means detachably attached to the tip of the tool rotation shaft, the tool can be easily exchanged and the operating rate of the apparatus is improved.

この実施の形態によれば、カップ状のツールの外径をワークの非研削部の外径の１．５倍〜２倍としたので、研削を担持する刃先長が十分に大きく得られ、砥石の摩耗が少なく、大きなワークに対する高い加工能力が得られ、安定生産できる。 According to this embodiment, since the outer diameter of the cup-shaped tool is 1.5 to 2 times the outer diameter of the non-grinding part of the workpiece, a sufficiently long cutting edge length for carrying grinding can be obtained. Wear is small, high machining capacity for large workpieces is obtained, and stable production is possible.

この実施の形態によれば、ツール支持手段の回転軸のＸ−Ｚ平面内のＺ軸に対する傾き角を４５°〜９０°の範囲内として可変し、研削するので、カップ状のツールがワークの研削すべき箇所以外の他の箇所に干渉することなく、また、ツールの振動の原因となるワークからツールに伝わる研削反力を所要大きさ以下に抑えられ、ビビリが生じない研磨が行える。 According to this embodiment, since the tilt angle of the rotation axis of the tool support means with respect to the Z axis in the XZ plane is varied within the range of 45 ° to 90 ° and grinding is performed, the cup-shaped tool can be It is possible to perform polishing without causing chatter without interfering with other parts other than the part to be ground, and by suppressing the grinding reaction force transmitted from the work causing vibration of the tool to the tool to a required level or less.

この実施の形態によれば、カップ状のツールの刃先角を約４５°としたので、ツール支持手段の回転軸のＸ−Ｚ平面内のＺ軸に対する傾き角を小さく抑えることができて、ツールの振動の原因となるワークからツールに伝わる研削反力を一層小さく抑えられ、ビビリが生じない研磨が行えて、鏡面研削に寄与する。
〔実施の形態２〕 According to this embodiment, since the cutting edge angle of the cup-shaped tool is about 45 °, the tilt angle of the rotation axis of the tool support means with respect to the Z axis in the XZ plane can be kept small, and the tool The grinding reaction force transmitted to the tool from the workpiece that causes vibration of the tool can be further reduced, and polishing without chatter can be performed, contributing to mirror grinding.
[Embodiment 2]

図３（ａ）〜（ｄ）は、先端面が外周面に対して直角乃至直角に近い鋭角であるカップ状のツールＴ４を用いて、ワークＷ４に対して、Ｂ軸上にツールＴ４とワークＷ４を点接触させ、ツールＴ４を、ワークＷ４の端面に形成された点対偶凸曲面に倣って、図３（ａ）→（ｂ）→（ｃ）→（ｄ）のツール運行行程（逆の行程でも良い）に示すように、ワークＷ４の端面に精密仕上げ切削加工された点対偶凸曲面に対して、平面→凹Ｒ面→非球面と精密に倣うように連続運行するところを示す行程図である。 FIGS. 3A to 3D show a tool T4 and a workpiece on the B axis with respect to the workpiece W4 using a cup-shaped tool T4 whose tip surface is an acute angle close to or perpendicular to the outer peripheral surface. W4 is brought into point contact, and the tool T4 is moved along the tool travel process shown in FIG. 3 (a) → (b) → (c) → (d) following the point-to-even convex curved surface formed on the end surface of the work W4. As shown in Fig. 2), a stroke diagram showing a point-to-even convex curved surface that has been precision-finished on the end face of the workpiece W4 and continuously operating so as to closely follow the plane → concave R surface → aspherical surface. It is.

この場合も、ツールＴ４の刃の先端角を２分割する分割線６９の延長線がワークＷ４の被研磨点における曲率中心を通るように保ち、点対偶凸曲面に対して研削する。この実施の形態のカップ状のツールＴ４は、刃先角が外周面に対して９０°又はこれに近い鋭角であるので、ワークＷ３の円周部の平面を研磨する際には、ツール回転軸６３の軸心のＸ軸に対する交差角が４５°又はこれに近い角度になる。 Also in this case, the extended line of the dividing line 69 that divides the tip angle of the blade of the tool T4 is passed through the center of curvature at the point to be polished of the workpiece W4, and the point-to-even convex curved surface is ground. The cup-shaped tool T4 of this embodiment has a cutting edge angle of 90 ° with respect to the outer peripheral surface or an acute angle close thereto, so that the tool rotation shaft 63 is used when polishing the plane of the circumferential portion of the workpiece W3. The crossing angle of the axis with respect to the X-axis is 45 ° or an angle close thereto.

この実施の形態によれば、刃先角の相違に関係する事項を除いて、実施の形態１と同様の効果が得られる。 According to this embodiment, the same effects as those of the first embodiment can be obtained except for matters related to the difference in the edge angle.

本発明は、上記一実施の形態に限られるものではなく、その趣旨と技術思想の範囲を逸脱しない範囲でさらに種々の変形が可能である。 The present invention is not limited to the one embodiment described above, and various modifications can be made without departing from the spirit and scope of the technical idea.

上記の実施の形態では、ワーク支持手段をＺ軸方向スライドテーブル５１に設けて、ワーク支持手段に回転とＺ軸方向スライドとを与え、また、回動テーブル５３をＸ軸方向スライドテーブル５２に設けて、ツール支持手段に回転とＸ軸方向スライドと回動テーブルの回動とを与えたが、これに限定されない。具体的には、ワーク支持手段を回転とＺ軸方向スライドさせずＺ軸方向に沿ったＣ軸に関して回転自在とし、かつ、回動テーブルをＸ軸−Ｚ軸方向にスライド自在である二次元テーブル上に設けることにより、ツール支持手段をＹ軸に沿ったＢ軸に関して回転自在とし、かつ、Ｘ軸及びＺ軸の二次元方向にスライド自在としても良い。 In the above embodiment, the work support means is provided on the Z-axis direction slide table 51, rotation and Z-axis direction slide are given to the work support means, and the rotation table 53 is provided on the X-axis direction slide table 52. Thus, the tool support means is rotated, rotated in the X-axis direction, and rotated by the rotation table, but is not limited thereto. Specifically, the work support means is not rotated and slid in the Z-axis direction, but is rotatable with respect to the C-axis along the Z-axis direction, and the rotary table is slidable in the X-axis-Z-axis direction. By providing it above, the tool support means may be rotatable with respect to the B axis along the Y axis and slidable in the two-dimensional direction of the X axis and the Z axis.

上記の実施の形態では、レンズ成形金型をワークとして非球面が平面に連続する点対偶凸曲面の研削について説明したが、本発明は、レンズ等の他のワークの端面の点対偶凸曲面を研削する点対偶凸曲面の研削にも適用される。また、ワーク回転軸によるワークの支持構造やツール回転軸によるツールの支持構造について、上記の実施の形態に示す構造に限定されるものではない。 In the above-described embodiment, the grinding of the point-even convex curved surface in which the aspherical surface is continuous with the plane using the lens molding die as a workpiece has been described, but the present invention provides the point-even convex curved surface of the end surface of another workpiece such as a lens. It is also applied to grinding point-to-even convex curved surfaces. Further, the work support structure by the work rotation axis and the tool support structure by the tool rotation axis are not limited to the structures shown in the above embodiments.

本発明の凸曲面研削方法を実施する研削装置の研削行程を示す概略平面図The schematic plan view which shows the grinding process of the grinding device which implements the convex curve grinding method of this invention 図１に示す研削装置の要部を拡大した研削行程を示す概略平面図The schematic plan view which shows the grinding process which expanded the principal part of the grinding apparatus shown in FIG. 本発明の他の実施形態の研削装置の要部を拡大した研削行程を示す概略平面図The schematic plan view which shows the grinding process which expanded the principal part of the grinding device of other embodiment of this invention. 従来の凸曲面研削方法を実施する研削装置の概略平面図Schematic plan view of a grinding apparatus for performing a conventional convex curved surface grinding method 従来の他の凸曲面研削方法を実施する研削装置の概略平面図Schematic plan view of a grinding apparatus for performing another conventional method for grinding a convex curved surface

符号の説明Explanation of symbols

５０…研削装置
５１…Ｚ軸方向スライドテーブル
５２…Ｘ軸方向スライドテーブル
５３…回動テーブル
５４…Ｂ軸
５７…ワーク回転軸
５７ａ…ワーク支持手段
５９…Ｃ軸
Ｗ３，Ｗ４…ワーク
６３…ツール回転軸
Ｔ３，Ｔ４…ツール
６７…フランジ（ツール支持手段） DESCRIPTION OF SYMBOLS 50 ... Grinding device 51 ... Z-axis direction slide table 52 ... X-axis direction slide table 53 ... Rotation table 54 ... B axis 57 ... Work rotation axis 57a ... Work support means 59 ... C axis W3, W4 ... Work 63 ... Tool rotation Axis T3, T4 ... Tool 67 ... Flange (tool support means)

Claims

Ｃ軸に回転自在のワーク支持手段にワークを支持し、
Ｃ軸と直角方向のＢ軸に回転自在の回動テーブルに備えられたＢ軸に直角面内を回動自在のツール支持手段の先端に、外径が前記ワークの被研削部の外径よりも所要大きいカップ状のツールを取り付け、かつ、該ツールの先端面外端を前記回動テーブルの回転中心であるＢ軸に一致させ、
前記ワーク支持手段と前記ツール支持手段に、それぞれ回転を与えると共に、Ｘ軸−Ｚ軸の二次元方向の相対的なスライドを与えることにより、前記回動テーブルの回転中心線上で前記ツールと前記ワークとを点接触させつつ前記ツールと前記ワークの相対的な向きを変えて、前記ワークの端面に形成された凸曲面に倣って研削することを特徴とする凸曲面研削方法。 The workpiece is supported by a workpiece support means that is rotatable on the C axis,
The outer diameter is larger than the outer diameter of the part to be ground of the workpiece at the tip of the tool support means that is rotatable in a plane perpendicular to the B axis and provided in a rotary table that is rotatable about the B axis perpendicular to the C axis. And attach the required large cup-shaped tool, and align the outer end of the tip end surface of the tool with the B axis which is the rotation center of the rotary table,
The tool support means and the tool support means are respectively rotated and given a relative slide in the two-dimensional direction of the X-axis and the Z-axis so that the tool and the work are rotated on the rotation center line of the rotary table. A convex curved surface grinding method characterized in that grinding is performed following a convex curved surface formed on an end surface of the workpiece by changing the relative orientation of the tool and the workpiece while making point contact with each other.

前記ツール支持手段のツール支持部の外径が前記カップ状のツールの外径にほぼ等しい大きさであること特徴とする請求項１に記載の凸曲面研削方法。 2. The convex curved surface grinding method according to claim 1, wherein an outer diameter of a tool support portion of the tool support means is substantially equal to an outer diameter of the cup-shaped tool.

前記ツール回転軸の先端に着脱可能なツール支持手段を備え、該ツール支持手段に支持された前記カップ状のツールにより研削することを特徴とする請求項１又は２に記載の凸曲面研削方法。 The convex curved surface grinding method according to claim 1, further comprising a tool support unit that can be attached and detached at a tip of the tool rotation shaft, and grinding with the cup-shaped tool supported by the tool support unit.

前記カップ状のツールは、外径が前記ワークの被研削部の外径の１．５倍〜２倍であること特徴とする請求項１乃至３の何れか一に記載の凸曲面研削方法。 The convex curved surface grinding method according to any one of claims 1 to 3, wherein the cup-shaped tool has an outer diameter of 1.5 to 2 times an outer diameter of a portion to be ground of the workpiece.

前記ツール支持手段の回転軸のＸ−Ｚ平面内のＺ軸に対する傾き角を４５°〜９０°の範囲内として可変し、研削することを特徴とする請求項１乃至４の何れか一に記載の凸曲面研削方法。 5. The grinding is performed by varying an inclination angle of the rotation axis of the tool support means with respect to the Z axis in the XZ plane within a range of 45 ° to 90 °. 5. Convex curve grinding method.

前記カップ状のツールは、刃先角が約４５°であること特徴とする請求項１乃至５の何れか一に記載の凸曲面研削方法。 The convex curved surface grinding method according to any one of claims 1 to 5, wherein the cup-shaped tool has a cutting edge angle of about 45 °.