JP2009066724A - Lens spherical face grinding method and device - Google Patents

Lens spherical face grinding method and device Download PDF

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JP2009066724A
JP2009066724A JP2007239612A JP2007239612A JP2009066724A JP 2009066724 A JP2009066724 A JP 2009066724A JP 2007239612 A JP2007239612 A JP 2007239612A JP 2007239612 A JP2007239612 A JP 2007239612A JP 2009066724 A JP2009066724 A JP 2009066724A
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lens
grinding
center
shaft
grindstone
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Tomoaki Obata
智昭 小幡
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Nakamura Tome Precision Industry Co Ltd
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Nakamura Tome Precision Industry Co Ltd
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<P>PROBLEM TO BE SOLVED: To provide a method and device for grinding the surface of a lens material into a spherical face with a grinding tool, particularly suitable for rough grinding using a cup grinding tool to actualize short-time rough grinding of a lens resulting in improved lens machining productivity. <P>SOLUTION: The lens spherical grinding method comprises gripping the lens material 4 with a lens holder 12 provided at the shaft end of a rotary work shaft 1, and rotating the cup grinding tool 3a in circular contact with the surface 43 of the lens material after ground to grind the surface 43 of the lens material into a spherical face. Instead of a conventional means for roughly grinding the lens material 4 while applying axial grinding feed to the cup grinding tool 3a, the cup grinding tool 3a fed by a predetermined grinding allowance e is circularly moved from the peripheral edge side of the lens material 4 to the center around a curvature center O of the lens surface 43 after ground. The grinding is completed with one rocking operation of a wheel shaft 25a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

この発明は、研削砥石でレンズ素材の表面を球面に研削する方法及び装置に関するもので、特に砥粒の粒度が300番前後のカップ砥石を用いる粗研削に特に好適な前記方法及び装置に関するものである。   The present invention relates to a method and apparatus for grinding the surface of a lens material into a spherical surface with a grinding wheel, and particularly to the method and apparatus particularly suitable for rough grinding using a cup grindstone having an abrasive grain size of about 300. is there.

レンズ球面の研削加工は、通常、カップ砥石による粗研削(球面創成加工)とペレット皿による1工程又は2工程の精研削の順で行われ、その後、磨き皿による研磨(ポリシング)が行われている。   The lens spherical surface is usually ground in the order of rough grinding with a cup grindstone (spherical surface creation processing) and fine grinding in one or two steps with a pellet dish, and then polishing with a polishing dish (polishing) is performed. Yes.

粗研削は、軸方向を鉛直方向としたワーク軸の上端のレンズホルダにレンズ素材を装着し、下端にレンズ素材の表面と円接触するカップ砥石を装着した砥石軸を研削しようとするレンズ表面の曲率に合わせて傾斜させ、カップ砥石とレンズ表面との接触円が丁度レンズの軸中心を通る位置に砥石軸を位置決めする。そしてワーク軸と砥石軸を回転し、サーボモータでワーク軸に上方向へ切削送りをかけて、レンズ表面に対するカップ砥石の公転と自転との合成運動により、レンズ球面を創成加工するというものである。   In rough grinding, the lens material is mounted on the lens holder at the upper end of the workpiece axis with the axial direction as the vertical direction, and the grinding wheel shaft with the cup wheel that is in circular contact with the surface of the lens material is mounted at the lower end. The wheel is tilted according to the curvature, and the grindstone shaft is positioned at a position where the contact circle between the cup grindstone and the lens surface passes through the center of the lens axis. Then, the workpiece shaft and the grinding wheel shaft are rotated, the workpiece is fed upward by a servo motor, and the spherical surface of the lens is created by the combined motion of the revolution and rotation of the cup grinding stone with respect to the lens surface. .

レンズの粗研削と精研削は、従来個別の機械で行われていたが、本願出願人は、同一機台上に粗研削用の砥石軸と精研削用の砥石軸とを設けて、ワークを持替えることなく粗研削と精研削とを連続して行うことができるレンズの球面研削装置を提案している(特許文献1)。図5は、特許文献1で提案したレンズの球面研削装置を示した側面図である。図中、1はワーク軸、11はワーク軸1駆動用の電動機、12はワーク軸1の先端(上端)に設けられたレンズホルダ、13はワーク軸1を軸支している昇降台(Z方向移動台)である。   Conventionally, rough grinding and fine grinding of lenses have been carried out by individual machines, but the applicant of the present application provides a grinding wheel shaft for rough grinding and a grinding stone shaft for fine grinding on the same machine stand. A spherical grinding device for a lens capable of continuously performing rough grinding and fine grinding without holding them is proposed (Patent Document 1). FIG. 5 is a side view showing a spherical grinding apparatus for a lens proposed in Patent Document 1. As shown in FIG. In the figure, 1 is a work shaft, 11 is an electric motor for driving the work shaft 1, 12 is a lens holder provided at the tip (upper end) of the work shaft 1, and 13 is a lifting platform (Z that supports the work shaft 1). Direction moving platform).

23は揺動中心P回りに揺動する揺動台、21は揺動台23上に設けたガイド、22はガイド21に沿って移動するX移動台(X方向移動台)である。X移動台22には、2本の砥石軸25a、25bが互いに平行に軸支されている。ガイド21は、この2本の砥石軸25a、25bと直交する方向に設けられている。   Reference numeral 23 denotes a swing base that swings around the swing center P, 21 denotes a guide provided on the swing base 23, and 22 denotes an X moving base (X direction moving base) that moves along the guide 21. Two grindstone shafts 25a and 25b are supported on the X moving table 22 in parallel with each other. The guide 21 is provided in a direction orthogonal to the two grindstone shafts 25a and 25b.

砥石軸25a、25bの下端(ワークホルダに向く軸端)には、工具ホルダ29a、29bが設けられ、その一方29aに粗研削用のカップ砥石3aが装着され、他方29bには、精研削用のペレット皿3bが装着されている。各砥石軸25a、25bには、砥石軸駆動用の電動機26a、26bが接続されている。   Tool holders 29a and 29b are provided at the lower ends (shaft ends facing the work holder) of the grindstone shafts 25a and 25b, and a cup grindstone 3a for rough grinding is mounted on one of them 29a, and the other 29b is used for fine grinding. The pellet dish 3b is mounted. The grindstone shafts 25a and 25b are connected to electric motors 26a and 26b for driving the grindstone shaft.

ワーク軸1は、フレーム2に昇降自在に案内された昇降台13に軸支されており、この昇降台と一体のブラケット14がZ軸サーボモータ17で駆動されるZ軸送りねじ18に螺合している。揺動台23は、B軸サーボモータ37で揺動駆動されている。X移動台22は、揺動台23に搭載したX軸サーボモータ27で回転駆動される送りねじ28に螺合している。5はこれらのサーボモータを制御するNC装置であり、51、52及び53は、サーボアンプ、19はZ軸サーボモータ17の電流制御器である。   The work shaft 1 is pivotally supported by a lifting platform 13 that is guided by a frame 2 so as to be movable up and down, and a bracket 14 integrated with the lifting platform is screwed into a Z-axis feed screw 18 driven by a Z-axis servomotor 17. is doing. The oscillating table 23 is oscillated by a B-axis servo motor 37. The X moving table 22 is screwed to a feed screw 28 that is rotationally driven by an X-axis servo motor 27 mounted on the swing table 23. Reference numeral 5 denotes an NC device for controlling these servo motors, 51, 52 and 53 are servo amplifiers, and 19 is a current controller for the Z-axis servo motor 17.

次に、上記装置でレンズの研削を行う手順を説明する。まず、NC装置5に研削するレンズ4の厚さや曲率半径などのデータを登録する。そして、カップ砥石3aを装着した砥石軸25aが揺動台23の揺動中心Pを通る位置をX移動台22の移動原点に設定し、研削するレンズ球面の曲率に対応する角度に揺動台23を傾斜させ、カップ砥石3aとレンズ球面との接触円がレンズの光軸を通る位置にX移動台22の位置を設定し、削り代に応じたワーク軸1の研削完了位置をZ軸の原点に設定する。   Next, a procedure for grinding a lens with the above apparatus will be described. First, data such as the thickness and curvature radius of the lens 4 to be ground is registered in the NC device 5. Then, the position where the grindstone shaft 25a on which the cup grindstone 3a is mounted passes through the rocking center P of the rocking table 23 is set as the moving origin of the X moving table 22, and the rocking table is set at an angle corresponding to the curvature of the lens spherical surface to be ground. 23 is tilted, the position of the X moving table 22 is set so that the contact circle between the cup grindstone 3a and the lens spherical surface passes through the optical axis of the lens, and the grinding completion position of the workpiece shaft 1 corresponding to the machining allowance is set to the Z axis. Set to the origin.

そして、レンズホルダ12にレンズ素材4を装填し、Z軸サーボモータ17に所定速度の切削送り指令を与えて、ワーク軸1の回転によるカップ砥石3aの公転と、砥石軸25aの回転によるカップ砥石3aの自転とにより、レンズ4の球面創成を行う。ワーク軸1が所定の削り代の位置に達したら、レンズの第1面に対する粗研削を終了する。   Then, the lens material 4 is loaded in the lens holder 12, a cutting feed command at a predetermined speed is given to the Z-axis servomotor 17, the revolution of the cup grindstone 3a by the rotation of the work shaft 1, and the cup grindstone by the rotation of the grindstone shaft 25a. The spherical surface of the lens 4 is created by the rotation of 3a. When the workpiece shaft 1 reaches a predetermined cutting allowance, rough grinding on the first surface of the lens is finished.

次にペレット皿3bを取付けた砥石軸25bが揺動台23の揺動中心Pを通る位置をX移動台22の移動原点に設定し、ワーク軸1を一旦下降してペレット皿3bをワーク4に対向させる。そして揺動台23を揺動中心P回りに所定角度で往復揺動させ、その揺動角θに対応して、x=dtanθ、z=d/cosθ‐dの関係が成立するように、X移動台22及び昇降台13を往復移動させる。ここで、dは揺動台23の揺動中心Pから研削するレンズの曲率中心Oまでの距離である。   Next, the position where the grindstone shaft 25b to which the pellet dish 3b is attached passes through the rocking center P of the rocking table 23 is set as the movement origin of the X moving table 22. To face. Then, the rocking base 23 is reciprocally swung around the rocking center P at a predetermined angle, and X = dtan θ and z = d / cos θ-d are established in correspondence with the rocking angle θ. The moving table 22 and the lifting table 13 are reciprocated. Here, d is the distance from the swing center P of the swing base 23 to the curvature center O of the lens to be ground.

そして、Z軸サーボモータ17に所定の付圧力に相当するトルク制限をかけた状態で、NC装置5から所定の削り代の位置(揺動台の角度θによって時々刻々と変化する。)への上昇指令を与える。この上昇途中でレンズ素材4の表面がペレット皿3bに当接して上昇が止まり、上記付圧力でレンズ素材4がペレット皿3bに押し付けられ、この状態でワーク軸1の回転によるペレット皿3bの公転と、砥石軸25bの回転によるペレット皿3bの自転と、ペレット皿3bのレンズ曲率中心を中心とする揺動とにより、レンズ素材4の精研削が行われる。
特開2006−297520号公報
Then, with the torque limit corresponding to the predetermined applied pressure applied to the Z-axis servomotor 17, the NC device 5 moves to a predetermined cutting allowance position (varies from moment to moment depending on the angle θ of the swing table). Give rise command. In the middle of the ascent, the surface of the lens material 4 comes into contact with the pellet dish 3b and the ascent is stopped, and the lens material 4 is pressed against the pellet dish 3b by the applied pressure. In this state, the revolution of the pellet dish 3b by the rotation of the work shaft 1 Then, the lens material 4 is precisely ground by the rotation of the pellet dish 3b by the rotation of the grindstone shaft 25b and the swinging of the pellet dish 3b around the center of the lens curvature.
JP 2006-297520 A

前述したように、従来のカップ砥石によるレンズの粗研削は、CG加工(球面創成加工)と呼ばれる方法で行われている。CG加工は、研削するレンズ表面の曲率に合わせた角度に砥石軸の角度を固定し、かつ、カップ砥石とレンズ球面との接触円が研削しようとするレンズの光軸を通る位置に砥石軸を固定した状態で、、ワーク軸に所定速度の切削送りを与えて、ワーク軸の回転によるカップ砥石の公転と、砥石軸の回転によるカップ砥石の自転とにより、レンズの球面創成加工を行うというものである。   As described above, the rough grinding of the lens with the conventional cup grindstone is performed by a method called CG processing (spherical surface creation processing). In CG processing, the angle of the grindstone shaft is fixed to an angle that matches the curvature of the lens surface to be ground, and the grindstone shaft is placed at a position where the contact circle between the cup grindstone and the lens spherical surface passes through the optical axis of the lens to be ground. In a fixed state, a cutting feed at a predetermined speed is given to the work shaft, and the spherical surface of the lens is created by the revolution of the cup grindstone by the rotation of the work shaft and the rotation of the cup grindstone by the rotation of the grindstone shaft. It is.

従来のCG加工方法では、砥石とワークが当たる面積が広く、加工負荷が大きく、ワーク一回転当りの砥石の切り込み量を大きくしたり、送り速度を速くしたりすることができない。そのため、加工速度が遅くなって一個のレンズを研削するのに要するタクトタイムが延びる問題や、機械精度、砥石の形状などにより、レンズ中心部に削り残し(へそ)ができることがあるという問題があった。レンズの材質や径によっても異なるが、従来のCG加工による一般的なレンズの粗研削に要する時間は約40secである。   In the conventional CG processing method, the area where the grindstone and the workpiece contact is large, the processing load is large, and the cutting amount of the grindstone per rotation of the workpiece cannot be increased, and the feed rate cannot be increased. For this reason, there is a problem that the processing time becomes slow and the tact time required to grind a single lens is increased, and there is a problem that an uncut portion (navel) can be left in the center of the lens due to machine accuracy, the shape of the grindstone, etc. It was. Although it depends on the material and diameter of the lens, the time required for rough grinding of a general lens by conventional CG processing is about 40 seconds.

特許文献1記載の発明では、粗研削と精研削との間でのレンズ素材の搬送やそれぞれの装置へのレンズ素材のロード・アンロード時間を節約できることから、レンズの研削時間を短縮することが可能である。この発明は、レンズの粗研削をより短時間で行うことができるようにして、レンズ加工の生産性を更に向上させることを課題としている。   In the invention described in Patent Document 1, the lens material can be transported between the rough grinding and the fine grinding, and the load / unload time of the lens material to each apparatus can be saved, so that the lens grinding time can be shortened. Is possible. An object of the present invention is to further improve the productivity of lens processing by enabling rough grinding of a lens in a shorter time.

この発明は、カップ砥石3aに軸方向の研削送りをかけてレンズ素材4を粗研削する従来手段に代えて、所定の研削代eだけ送り込んだカップ砥石3aをレンズ素材4の周縁側から中心へと研削後のレンズ表面43の曲率中心O回りに円弧移動させることにより、砥石軸25aの一揺動動作で研削を完了させることにより、上記課題を解決したものである。   In the present invention, instead of the conventional means for roughly grinding the lens material 4 by applying axial grinding feed to the cup grindstone 3a, the cup grindstone 3a fed by a predetermined grinding allowance e from the peripheral side of the lens material 4 to the center. The above problem is solved by moving the arc around the center of curvature O of the lens surface 43 after grinding to complete the grinding by one swinging motion of the grindstone shaft 25a.

本願の請求項1の発明に係るレンズの球面研削方法は、回転するワーク軸1の軸端に設けたレンズホルダ12でレンズ素材4を把持し、当該レンズ素材の研削後の表面43に円接触するカップ状の研削砥石3aを回転させてレンズ素材の表面43を球面研削するレンズの球面研削方法において、前記円接触の接触円が研削前のレンズ4の周縁の外側となる位置aにカップ砥石3aを移動させた後、研削後のレンズ表面43の曲率中心Oから研削後のレンズ表面43の曲率半径に相当する距離Rを隔てた位置に当該砥石を前進させ、前記距離Rを保持した状態で前記接触円がレンズ表面の中心を通る位置cまで前記曲率中心Oを中心としてカップ砥石3aを円弧移動させることを特徴とする、レンズの球面研削方法である。   In the spherical grinding method for a lens according to the invention of claim 1 of the present application, the lens material 4 is gripped by the lens holder 12 provided at the shaft end of the rotating work shaft 1, and the surface 43 of the lens material after grinding is in circular contact. In a spherical grinding method of a lens in which the cup-shaped grinding wheel 3a is rotated to spherically grind the surface 43 of the lens material, the cup grinding stone is positioned at a position a where the contact circle of the circular contact is outside the periphery of the lens 4 before grinding. After moving 3a, the grindstone is advanced to a position separated from the center of curvature O of the ground lens surface 43 by a distance R corresponding to the radius of curvature of the ground lens surface 43, and the distance R is maintained. In this method, the cup grindstone 3a is moved in a circular arc around the center of curvature O to a position c where the contact circle passes through the center of the lens surface.

本願の請求項2の発明に係るレンズの球面研削装置は、上記のこの発明の方法でレンズの球面研削を行う装置である。すなわち、軸端にレンズホルダ12を設けた回転ワーク軸1と、揺動中心P回りに揺動する揺動台23と、この揺動台に軸支されて回転する砥石軸25aと、この砥石軸軸端の砥石ホルダ29aに装着されて前記レンズホルダ12に対向するカップ状の研削砥石3aと、回転ワーク軸1と砥石軸25aとの相対軸方向距離及び揺動台23の揺動を制御する制御器とを備えた球面研削装置において、前記制御器は、レンズホルダ12に把持されたレンズ素材4の研削後の表面43と研削砥石3aとの接触円が研削前のレンズ素材4の周縁の外側となる位置aに砥石3aを移動させる動作と、当該移動した砥石3aを前記表面43の曲率中心Oから当該表面の曲率半径Rに相当する距離を隔てた位置に砥石3aを接近させる動作と、前記距離Rを保持した状態で前記接触円がレンズ素材表面43の中心を通る位置cまで前記曲率中心Oを中心として砥石3aを円弧移動させる動作とを順次行わせることを特徴とする、レンズの球面研削装置である。   A spherical grinding apparatus for a lens according to the invention of claim 2 of the present application is an apparatus for performing spherical grinding of a lens by the method of the present invention described above. That is, the rotary work shaft 1 provided with the lens holder 12 at the shaft end, the swing base 23 swinging around the swing center P, the grindstone shaft 25a rotating on the swing base, and the grindstone Controls the relative axial distance between the rotating workpiece shaft 1 and the grindstone shaft 25a, and the swing of the rocking table 23, mounted on the grindstone holder 29a at the end of the shaft and facing the lens holder 12. In the spherical grinding apparatus including the controller, the controller is configured such that the contact circle between the ground surface 43 of the lens material 4 held by the lens holder 12 and the grinding wheel 3a is the periphery of the lens material 4 before grinding. The operation of moving the grindstone 3a to the position a on the outside of the wheel and the operation of moving the grindstone 3a closer to a position corresponding to the curvature radius R of the surface from the center of curvature O of the surface 43 And the distance R A spherical grinding apparatus for a lens, characterized in that, in a held state, the operation of moving the grindstone 3a in a circular arc around the center of curvature O to a position c where the contact circle passes through the center of the lens material surface 43 is sequentially performed. is there.

本願の請求項3の発明は、好ましい構造の上記レンズの球面研削装置である。すなわち、Z方向移動台(昇降台)13に軸支されて先端に設けたレンズホルダ12で把持したレンズ素材4をその中心回りに回転させるワーク軸1と、このワーク軸の軸線Wを通って直交する揺動中心Pの軸線回りに揺動する揺動台23と、この揺動台に設けられたX移動台22と、このX移動台にその移動方向と直交する方向に軸支されて回転駆動される砥石軸25aと、揺動中心Pからレンズ表面43の研削後の曲率中心Oまでの距離dを演算して、x=dtanθ 及び z=d/cosθ‐dの関係を保持して前記揺動台の揺動角θ、X方向移動台の移動量x及びZ方向移動台の移動量zを制御する制御装置とを備えている、請求項2記載のレンズの球面研削装置である。   The invention of claim 3 of the present application is a spherical grinding apparatus for the lens having a preferred structure. That is, it passes through the workpiece shaft 1 that rotates around the center of the lens material 4 supported by the Z-direction moving table (lifting table) 13 and held by the lens holder 12 provided at the tip, and the axis W of the workpiece axis. A swing base 23 that swings about the axis of the orthogonal swing center P, an X moving base 22 provided on the swing base, and is supported by the X moving base in a direction perpendicular to the moving direction. The distance d from the grindstone shaft 25a to be rotationally driven and the center of curvature P of the lens surface 43 after grinding is calculated, and the relationship of x = dtanθ and z = d / cosθ-d is maintained. The spherical grinding device for a lens according to claim 2, further comprising: a control device that controls a swing angle θ of the swing table, a movement amount x of the X direction moving table, and a movement amount z of the Z direction moving table. .

この発明の方法(揺動によるCG加工方法)では、加工負荷が小さいため、砥石の切り込み量を大きくしたり、送り速度を速くしたりすることができ、タクトタイムの短縮ができる。すなわち、従来の加工に比べて加工負荷が小さく、レンズ一回転当りの砥石の切り込み量を増やすことができ、また、砥石の送り速度を速くすることができるため、タクトタイムの短縮ができる。更に、点に近い小さな面積で研削を行うポイント加工のため、レンズ中心部を越えて加工ができ、削り残し(へそ)ができることがない。   In the method of the present invention (CG machining method by rocking), since the machining load is small, the cutting amount of the grindstone can be increased, the feed rate can be increased, and the tact time can be shortened. That is, the processing load is small compared to the conventional processing, the cutting amount of the grindstone per lens rotation can be increased, and the feeding speed of the grindstone can be increased, so that the tact time can be shortened. Further, since the point processing is performed with grinding in a small area close to the point, the processing can be performed beyond the center of the lens, and no uncut portion (navel) can be formed.

この発明の方法で粒度300番前後のカップ砥石を用いてレンズの粗研削を行った場合、切込み深さ(取り代)0.5mmで20mm/minの速度で砥石を移動させることができる。従って直径10mmのレンズで約0.25分、直径5mmのレンズであれば0.125分で粗研削を完了することができる。レンズの径が大きいと粗研削時間は長くなるが、現在はレンズ計の小さいレンズの加工が殆どであるので、この発明により、レンズの球面研削の生産性を大幅に向上させることができる。   When the lens is roughly ground using a cup grindstone having a particle size of about 300 in the method of the present invention, the grindstone can be moved at a cutting depth (removal allowance) of 0.5 mm at a speed of 20 mm / min. Therefore, rough grinding can be completed in about 0.25 minutes with a 10 mm diameter lens and 0.125 minutes with a 5 mm diameter lens. If the diameter of the lens is large, the rough grinding time becomes long. However, at present, the processing of a lens having a small lens meter is mostly performed. Therefore, according to the present invention, the productivity of spherical grinding of the lens can be greatly improved.

次に図面を参照して、この発明の実施形態を説明する。図1は、この発明の球面研削方法の原理を示した側面図、図2は同平面図、図3は図1の方法で球面研削を行う球面研削装置の要部の側面図である。図において、4はレンズ素材、3aはカップ砥石、Wはレンズ素材4の回転中心軸(ワーク軸1の軸心)、Gはカップ砥石3aの回転中心軸(砥石軸25aの軸心)、Oは研削後のレンズ表面43の曲率中心、Rは研削後のレンズ表面43の曲率半径、eは研削代(取り代)、図2のa、b、cは、カップ砥石3aのレンズ表面43との接触円で、図2のa、b、cがそれぞれ図1の(a)、(b)、(c)の状態に対応している。   Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing the principle of the spherical grinding method of the present invention, FIG. 2 is a plan view of the same, and FIG. 3 is a side view of a main part of a spherical grinding apparatus for performing spherical grinding by the method of FIG. In the figure, 4 is a lens material, 3a is a cup grindstone, W is a rotation center axis of the lens material 4 (axis of the work shaft 1), G is a rotation center axis of the cup grindstone 3a (axis of the grindstone shaft 25a), O Is a center of curvature of the lens surface 43 after grinding, R is a radius of curvature of the lens surface 43 after grinding, e is a grinding allowance (removal allowance), a, b, and c in FIG. 2 are the lens surface 43 of the cup grindstone 3a. 2, a, b, and c in FIG. 2 correspond to the states of (a), (b), and (c) in FIG. 1, respectively.

図3を参照して、上端のレンズホルダ12でレンズ素材4を保持しているワーク軸1は、軸方向(Z軸方向)に昇降自在である。カップ砥石3aを支持している砥石軸25aは、揺動中心P回りに揺動する揺動台23に軸方向位置を調整可能に軸支されている。揺動中心Pの軸線は、ワーク軸の軸心Wを通ってこれと直交している。   With reference to FIG. 3, the work shaft 1 holding the lens material 4 with the lens holder 12 at the upper end can freely move up and down in the axial direction (Z-axis direction). The grindstone shaft 25a supporting the cup grindstone 3a is pivotally supported by an oscillating table 23 that oscillates about the oscillating center P so that its axial position can be adjusted. The axis of the swing center P passes through the axis W of the workpiece axis and is orthogonal thereto.

レンズ素材4は、ワーク軸1を下降させた状態でレンズホルダ12に装填される。揺動台23は、カップ砥石3aの接触円aがレンズ素材4の外縁から外れた図1(a)の位置となるまで揺動し、その後ワーク軸1が所定高さに上昇する。この所定高さは、カップ砥石の接触円aが研削後のレンズ表面43を含む球面上の位置となる高さである。カップ砥石3aは、このとき研削後のレンズ表面43の曲率中心Oが揺動台の揺動中心Pと一致するように、軸方向位置に予め調整しておく。   The lens material 4 is loaded into the lens holder 12 with the work shaft 1 lowered. The oscillating base 23 oscillates until the contact circle a of the cup grindstone 3a reaches the position shown in FIG. 1A where the contact circle a deviates from the outer edge of the lens material 4, and then the workpiece shaft 1 rises to a predetermined height. This predetermined height is the height at which the contact circle a of the cup grindstone is located on the spherical surface including the lens surface 43 after grinding. At this time, the cup grindstone 3a is adjusted in advance to the axial position so that the center of curvature O of the lens surface 43 after grinding coincides with the swing center P of the swing base.

この状態でレンズ素材4とカップ砥石3aを回転させ、カップ砥石3aをその回転中心軸Gとレンズの回転中心軸Wとの成す角度θが小さくなる方向に揺動させると、レンズ素材4は図1(b)に示す状態を経て、その接触円cがレンズの回転中心軸Wを通る位置に達した図1(c)の状態で、レンズ素材4の粗研削が終了する。   When the lens material 4 and the cup grindstone 3a are rotated in this state, and the cup grindstone 3a is swung in a direction in which the angle θ between the rotation center axis G and the rotation center axis W of the lens decreases, the lens material 4 is After the state shown in 1 (b), the rough grinding of the lens material 4 is completed in the state of FIG. 1 (c) where the contact circle c has reached the position passing through the rotation center axis W of the lens.

実際の球面研削装置では、凸レンズと凹レンズで曲率中心Oの位置が反対方向になるなど、研削するレンズによって曲率中心Oの位置が大きく変動する。種々のレンズを研削することを目的とした汎用の球面研削装置では、揺動台の揺動中心Pを研削するレンズの曲率中心Oに一致させて研削を行うことは殆ど不可能である。カップ砥石3aの揺動中心Pと研削するレンズの曲率中心Oとが一致していない状態でこの発明の方法による研削を行うときは、砥石中心軸Gとレンズ中心軸Wとが成す角度θに対応して、レンズ4とカップ砥石3aとの相対位置関係を、レンズ4の軸方向移動とカップ砥石3aの軸直角方向移動とによって、変更しながら研削を行う。図4は、この場合の研削方法を示した図で、図5に示した球面研削装置のカップ砥石3aでこの発明の方法による粗研削を行う例である。   In an actual spherical grinding apparatus, the position of the center of curvature O varies greatly depending on the lens to be ground, such as the positions of the center of curvature O being opposite between the convex lens and the concave lens. In a general-purpose spherical grinding apparatus intended to grind various lenses, it is almost impossible to perform grinding by matching the rocking center P of the rocking table with the curvature center O of the lens to be ground. When the grinding according to the method of the present invention is performed in a state where the swing center P of the cup grindstone 3a does not coincide with the curvature center O of the lens to be ground, the angle θ formed by the grindstone center axis G and the lens center axis W is set to the angle θ. Correspondingly, grinding is performed while the relative positional relationship between the lens 4 and the cup grindstone 3a is changed by the axial movement of the lens 4 and the perpendicular movement of the cup grindstone 3a. FIG. 4 is a diagram showing a grinding method in this case, and is an example in which rough grinding is performed by the method of the present invention using the cup grindstone 3a of the spherical grinding device shown in FIG.

図4を参照して、粗研削用のカップ砥石3aを取付けた砥石軸25aの軸心Gが揺動台23の揺動中心Pを通る位置をX移動台22の移動原点に設定し、揺動台23の揺動中心Pから研削後のレンズ表面43の曲率中心Oまでの距離をdとし、研削後のレンズ表面43の頂点(中心軸Wが通る位置)を昇降台13の原点に設定して、揺動台23の揺動角(砥石軸の傾斜角)がθのときのX移動台22の位置x及び昇降台13の位置zに、
x=dtanθ
z=d/cosθ‐d
の関係が成立するように、NC装置5からのX移動台22の位置指令及びワーク軸1の位置指令を変化させる。これにより、カップ砥石3aは、レンズ球面の曲率中心Oを中心として揺動する。
Referring to FIG. 4, the position where the axis G of the grindstone shaft 25 a to which the cup grindstone 3 a for rough grinding is attached passes through the rocking center P of the rocking table 23 is set as the moving origin of the X moving table 22. The distance from the swing center P of the moving table 23 to the center of curvature O of the lens surface 43 after grinding is set as d, and the apex (position through which the central axis W passes) of the lens surface 43 after grinding is set as the origin of the lifting platform 13. Then, the position x of the X moving table 22 and the position z of the lifting table 13 when the rocking angle of the rocking table 23 (the inclination angle of the grindstone axis) is θ,
x = dtanθ
z = d / cos θ-d
The position command of the X moving table 22 and the position command of the work axis 1 from the NC device 5 are changed so that the relationship is established. As a result, the cup grindstone 3a swings around the center of curvature O of the lens spherical surface.

NC装置による上記制御の下で、レンズ素材4とカップ砥石3aとの間には、図1で示した移動位置関係が成立するので、図1で説明したと同様な手順により、レンズ素材4の球面研削を行うことができる。すなわち、レンズホルダ12に把持されたレンズ素材の研削後の表面43とカップ砥石3aとの接触円aが研削前のレンズ素材周縁の外側となる位置にカップ砥石3aを移動させ、次に研削後のレンズ表面43の曲率中心0から当該表面の曲率半径Rに相当する距離を隔てた位置にカップ砥石3aが位置するようにレンズ素材4を前進させ、この状態から前記のx、z、θの関係を保持して接触円cがレンズ素材表面の中心を通る位置まで曲率中心Oを中心としてカップ砥石3aを円弧移動させることにより、レンズ素材4の球面研削が行われる。   Under the above control by the NC device, the movement positional relationship shown in FIG. 1 is established between the lens material 4 and the cup grindstone 3a. Spherical grinding can be performed. That is, the cup grindstone 3a is moved to a position where the contact circle a between the ground surface 43 of the lens material gripped by the lens holder 12 and the cup grindstone 3a is outside the periphery of the lens material before grinding, and then after grinding. The lens material 4 is advanced so that the cup grindstone 3a is positioned at a position corresponding to the radius of curvature R of the surface of the lens surface 43 at a distance corresponding to the curvature radius R of the lens surface 43. From this state, the x, z, θ The spherical grinding of the lens material 4 is performed by moving the cup grindstone 3a around the center of curvature O to a position where the contact circle c passes the center of the lens material surface while maintaining the relationship.

粗研削が終了したレンズ素材は、ペレット皿3bで従来と同様な方法により精研削を行ってやればよいが、図5に示した球面研削装置の砥石軸25bに砥粒が1000〜3000番程度の精研削用のカップ砥石を装着して従来の粗研削加工と同様な球面創成加工により、精研削を行うこともできる。すなわち、図5の装置の精研削用の砥石軸25bの下端にレンズ素材の表面と円接触する精研削用のカップ砥石を装着し、当該砥石軸25bを精研削後のレンズ表面の曲率に合わせて傾斜させ、当該カップ砥石とレンズ表面との接触円が丁度レンズの軸中心を通る位置(図2の接触円cの位置)に砥石軸25bを位置決めする。そしてワーク軸1と砥石軸25bを回転し、サーボモータでワーク軸1に上方向へ切削送りをかけて、レンズ表面に対するカップ砥石の公転と自転との合成運動により、レンズ球面を創成加工するのである。   The lens material that has been subjected to rough grinding may be finely ground by the same method as in the past using the pellet dish 3b, but the abrasive grains on the grinding wheel shaft 25b of the spherical grinding device shown in FIG. It is possible to perform fine grinding by mounting a cup grinding wheel for fine grinding and performing spherical surface creation similar to conventional rough grinding. That is, a precision grinding cup grindstone that is in circular contact with the surface of the lens material is mounted on the lower end of the grinding wheel shaft 25b for fine grinding in the apparatus of FIG. 5, and the grinding stone shaft 25b is matched to the curvature of the lens surface after fine grinding. The grindstone shaft 25b is positioned at a position where the contact circle between the cup grindstone and the lens surface passes through the center of the lens axis (the position of the contact circle c in FIG. 2). Since the workpiece shaft 1 and the grindstone shaft 25b are rotated, the workpiece shaft 1 is cut and fed upward by a servo motor, and the lens spherical surface is created by the combined movement of the revolution and rotation of the cup grindstone with respect to the lens surface. is there.

この発明の研削方法の原理を説明した側面図Side view explaining the principle of the grinding method of the present invention 同上面図Top view 図1の方法で研削を行う最も簡単な構造の球面研削装置の要部を示す側面図The side view which shows the principal part of the spherical grinding device of the simplest structure which grinds by the method of FIG. より現実的な装置でこの発明の球面研削を行う方法を示す説明図Explanatory drawing which shows the method of performing spherical grinding of this invention with a more realistic device この発明の方法でレンズ素材の粗研削を行う球面研削装置の一例を示した側面図Side view showing an example of a spherical grinding device for rough grinding of a lens material by the method of the present invention

符号の説明Explanation of symbols

1 ワーク軸
3a カップ砥石
4 レンズ素材
12 レンズホルダ
13 昇降台(Z方向移動台)
22 X移動台(X方向移動台)
23 揺動台
25a 砥石軸
29a 工具ホルダ
43 研削後のレンズ表面
O 研削後のレンズ表面の曲率中心
P カップ砥石の揺動中心
d O−P間の距離
1 Work axis
3a Cup whetstone 4 Lens material
12 Lens holder
13 Lifting platform (Z-direction moving platform)
22 X moving table (X direction moving table)
23 Swing base
25a Wheel axis
29a Tool holder
43 Lens surface after grinding O Center of curvature of lens surface after grinding P Center of oscillation of the cup grinding wheel d O-P distance

Claims (3)

回転するワーク軸の軸端に設けたレンズホルダでレンズ素材を把持し、当該レンズ素材の研削後の表面に円接触するカップ状の研削砥石を回転させて当該レンズ素材の表面を球面研削するレンズの球面研削方法において、
前記円接触の接触円が研削前のレンズ周縁の外側となる位置に前記砥石を移動させた後、研削後のレンズ表面の曲率中心から研削後のレンズ表面の曲率半径に相当する距離を隔てた位置に当該砥石を前進させ、前記距離を保持した状態で前記接触円がレンズ表面の中心を通る位置まで前記曲率中心を中心として当該砥石を円弧移動させることを特徴とする、レンズの球面研削方法。
A lens that grips the lens material with a lens holder provided at the end of the rotating workpiece shaft and rotates the cup-shaped grinding wheel that makes circular contact with the ground surface of the lens material to spherically grind the surface of the lens material In the spherical grinding method of
After moving the grindstone to a position where the contact circle of the circular contact is outside the lens periphery before grinding, a distance corresponding to the radius of curvature of the lens surface after grinding was separated from the center of curvature of the lens surface after grinding. A method of spherical grinding of a lens, wherein the grinding wheel is moved to a position, and the grinding wheel is moved in an arc around the center of curvature to a position where the contact circle passes through the center of the lens surface with the distance maintained. .
軸端にレンズホルダ(12)を設けた回転ワーク軸(1)と、揺動中心(P)回りに揺動する揺動台(23)と、この揺動台に軸支されて回転する砥石軸(25a)と、この砥石軸軸端の砥石ホルダ(29a)に装着されて前記レンズホルダに対向するカップ状の研削砥石(3a)と、前記回転ワーク軸と砥石軸との相対軸方向距離及び前記揺動台の揺動を制御する制御器とを備えた球面研削装置において、
前記制御器は、前記レンズホルダに把持されたレンズ素材の研削後の表面と前記研削砥石との接触円が研削前のレンズ素材周縁の外側となる位置に前記砥石を移動させる動作と、前記表面の曲率中心から当該表面の曲率半径に相当する距離を隔てた位置に当該砥石を接近させる動作と、前記距離を保持した状態で前記接触円がレンズ素材表面の中心を通る位置まで前記曲率中心を中心として当該砥石を円弧移動させる動作とを順次行わせることを特徴とする、レンズの球面研削装置。
A rotating work shaft (1) having a lens holder (12) at the shaft end, a swinging base (23) swinging around a swinging center (P), and a grindstone that is supported by the swinging base and rotates. Relative axial distance between the shaft (25a), the cup-shaped grinding wheel (3a) mounted on the grinding wheel holder (29a) at the end of the grinding wheel shaft shaft and facing the lens holder, and the rotating work shaft and the grinding wheel shaft And a spherical grinding apparatus comprising a controller for controlling the swing of the swing table,
The controller is configured to move the grindstone to a position where a contact circle between the ground surface of the lens material gripped by the lens holder and the grinding wheel is outside the periphery of the lens material before grinding; An operation of bringing the grindstone closer to a position separated from the center of curvature of the surface by a distance corresponding to the radius of curvature of the surface, and the center of curvature until the contact circle passes through the center of the lens material surface while maintaining the distance. A spherical grinding apparatus for a lens, which sequentially performs an operation of moving the grindstone in an arc as a center.
Z方向移動台(13)に軸支されてその先端に設けたレンズホルダ(12)で把持したレンズ素材をその中心軸回りに回転させるワーク軸(1)と、このワーク軸の軸線を通って直交する揺動中心(P)の軸線回りに揺動する揺動台(23)と、この揺動台に設けられたX移動台(22)と、このX移動台にその移動方向と直交する方向に軸支されて回転駆動される砥石軸(25a)と、前記揺動中心(P)からレンズ表面の研削後の曲率中心(O)までの距離(d)を演算して、x=dtanθ 及び z=d/cosθ‐dの関係を保持して前記揺動台の揺動角(θ)、X方向移動台の移動量(x)及びZ方向移動台の移動量(z)を制御する制御装置とを備えている、請求項2記載のレンズの球面研削装置。   A workpiece axis (1) that rotates around the central axis of the lens material supported by the lens holder (12) that is pivotally supported by the Z-direction moving base (13) and that is provided at the tip, and passes through the axis of the workpiece axis. A swing base (23) that swings about the axis of the orthogonal swing center (P), an X moving base (22) provided on the swing base, and the X moving base is orthogonal to the moving direction. The distance (d) from the grinding wheel shaft (25a) supported and rotated in the direction to the rotation center and the center of curvature (O) after grinding of the lens surface from the rocking center (P) is calculated, and x = dtan θ And z = d / cos θ-d is maintained, and the swing angle (θ) of the swing table, the movement amount (x) of the X-direction moving table, and the movement amount (z) of the Z-direction moving table are controlled. A spherical grinding device for a lens according to claim 2, comprising a control device.
JP2007239612A 2007-09-14 2007-09-14 Lens spherical face grinding method and device Pending JP2009066724A (en)

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WO2011092748A1 (en) 2010-01-29 2011-08-04 有限会社コジマエンジニアリング Lens spherical surface grinding method using dish-shaped grindstone
JP2013226620A (en) * 2012-04-25 2013-11-07 Olympus Corp Method for manufacturing lens and lens manufacturing apparatus
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WO2011092748A1 (en) 2010-01-29 2011-08-04 有限会社コジマエンジニアリング Lens spherical surface grinding method using dish-shaped grindstone
KR20120123082A (en) 2010-01-29 2012-11-07 유겐가이샤 코지마 엔지니어링 Lens spherical surface grinding method using dish-shaped grindstone
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CN109414796B (en) * 2016-07-08 2021-02-02 小岛工程股份有限公司 Method and apparatus for processing lens spherical surface using cup-shaped grindstone
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