JP3147982B2 - Lens grinding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic dressing lens grinding apparatus capable of adjusting a dressing in a grinding process of a workpiece such as a lens.

[0002]

2. Description of the Related Art Conventionally, as an electrolytic dressing grinding apparatus, for example, the invention described in Japanese Patent Application Laid-Open No. 3-43144 has been disclosed. In the above invention, as shown in FIG. 16, a conductive grinding tool 91 having a processing surface formed in a hemispherical shape is attached to the tip of a rotating shaft 90 rotatably held. The grinding tool 91 is formed by forming abrasive grains such as diamond powder with a conductive bond. Grinding tool 9
The processed member 92 has a shape corresponding to the processed surface.
Is in contact. The workpiece 92 is a rotatable holding plate 9.
3 is held. On the outer periphery of the holding plate 93, a ring-shaped electrode 94 set so as to have a slight gap 1 with the processing surface of the grinding tool 91 while holding the workpiece 92 is attached.

In the vicinity of the grinding tool 91 and the holding plate 93, a pipe 96 for supplying a coolant 95 to the small gap 1 is provided. A brush 98 connected to the anode of a DC power supply 97 is in contact with the outer periphery of the rotating shaft 90.
Further, a cathode of a DC power supply 97 is connected to a swingable wrench 99 that engages with the holding plate 94.

In the apparatus having the above-described structure, the holding plate 93 is swung by a screw 99 and the grinding tool 91 is rotated. At the same time, the anode is applied to the rotating shaft 90 and the cathode is applied to the electrode 94 from the DC power supply 97, and the coolant 95 is supplied to the slight gap l for processing. During this machining, electrolysis is generated on the machining surface of the grinding tool 91, and the machining surface of the grinding tool 91 can be ground while being dressed.

[0005]

However, in the prior art, the ring-shaped (-) electrode performs electrolytic dressing at each point of the grinding tool. In general, in electrolytic dressing, the lower the peripheral speed of the grinding tool, the better the space around the coolant, the stronger the electrolysis, and the more the dressing proceeds. Therefore, in a hemispherical grinding tool, the peripheral speed differs in the radial direction, and the peripheral speed is 0 (m / mi) at the center.
n).

[0006] Therefore, when a certain electrolytic dressing is performed using a ring-shaped electrode, the electrolysis acts strongly toward the center of the grinding tool, and weakens toward the outer periphery.
Therefore, the shape of the grinding tool gradually collapses, and accordingly, the shape accuracy of the work decreases.

[0007] Further, according to the prior art, when the shape of the grinding tool is broken, the electrolytic dressing cannot be adjusted, and the shape of the grinding tool cannot be corrected.

Therefore, the present invention has been developed in view of the above-mentioned problems in the prior art, and maintains the shape of the grinding tool by adjusting the electrolytic strength by using (−) electrodes having partially different electric resistances. It is another object of the present invention to provide a lens grinding apparatus capable of performing the above-mentioned operations and further correcting the shape of the grinding tool.

[0009]

According to a first aspect of the present invention, there is provided a lens grinding apparatus in which a conductive grinding tool applied to an anode is rotated so as to keep a constant distance from a processing surface of the conductive grinding tool. In a lens grinding apparatus that applies an electrode to a cathode and relatively oscillates a conductive grinding tool and a work in a state where a weakly conductive coolant is interposed between the conductive grinding tool and the electrode, the electrode includes: It is a ring-shaped member provided on the outer periphery of the work, and is constituted by a plurality of members having different electric conductivity in the circumferential direction.

In the lens grinding apparatus according to the second invention, the conductive grinding tool applied to the anode is rotated, and the electrode arranged so as to keep a constant distance from the working surface of the conductive grinding tool is used as the cathode. A conductive grinding tool and a workpiece are relatively oscillated in a state where a weakly conductive coolant is interposed between the conductive grinding tool and the electrode. Or, a resistance member whose resistance changes analogously in the circumferential direction, and a ring-shaped electrode provided on the outer periphery of the work and in contact with the resistance member,
It is provided with.

Further, in the lens grinding device according to the third invention, in the lens grinding device according to the first or second invention, when the center of the conductive grinding tool or its vicinity is located at the outermost periphery of the electrode. Only a switch for energizing only is provided.

[0012]

[Embodiment 1] First, before describing a specific embodiment of the present invention, an outline of the present invention will be described. FIG. 1 is a conceptual diagram showing the present invention, and FIG. 2 is a sectional view taken along line XX 'of FIG. In a lens grinding and polishing apparatus, a grinding tool 2 integrally formed and conductive and having a hemispherical tip is attached to the tip of a rotating shaft 1 connected to a driving device (not shown). Have been. A workpiece 4 having an end surface of the same shape, that is, a processing surface, is in contact with the upper surface of the grinding tool 2. A work holder 3 is mounted under pressure, which is a plate-like shape for mounting and holding the work 4 and whose center portion is swingable by engagement with a spherical end portion of a bar-shaped kansashi 5. The rotating shaft 1 swings with respect to the workpiece 4.

The rotating shaft 1 is connected via a brush 7 to the anode of a power source 6 for generating a pulse current. An insulator 10 is interposed between the (-) electrodes 9a to 9d. Also,
Each of the (-) electrodes 9a to 9d is connected to the cathode of the power source 6, and the electrical resistance decreases as a → d. Furthermore, the (-) electrode 9 does not rotate dependently. A weak electric coolant is supplied from a pump (not shown) through a coolant nozzle 15 to a gap between the (-) electrode 9 and the grinding tool 2 and a work processing surface.

In the apparatus having the above configuration, when the grinding tool 2 is swung in a spherical center to grind the work 4 into a spherical surface, the (-) electrode 9a having a high electric resistance is located near the rotation center of the grinding tool 2. , And (−) electrodes 9 a to 9 d are connected, and the grinding tool 2 is connected to the anode via a brush 7. The gap between the (−) electrode 9 and the grinding tool 2 is weaker than the coolant nozzle 15. Electrolytic dressing by supplying coolant. Therefore, the current is more likely to flow toward the outer periphery of the grinding tool 2, and the electrolytic strength is increased. Therefore, the change in the electrolysis speed due to the influence of the peripheral speed of the grinding tool 2 is canceled. Further, the shape of the grinding tool 2 is corrected by moving the (-) electrode 9d having a low electric resistance to a portion where the electrolysis is to be strengthened.

Next, specific embodiments of the present invention will be described with reference to the drawings. 3 to 5 show this embodiment, FIG. 3 is a cross-sectional view partially omitted, FIG. 4 is a cross-sectional view taken along line AA ′ of FIG. 3, and FIG. 5 is a cross-sectional view taken along line BB ′ of FIG. It is. In a lens grinding and polishing apparatus, a grinding tool 2 having conductivity formed integrally at the tip of a rotating shaft 1 connected to a drive source device (not shown) and having a tip formed in a hemispherical shape.
Is attached. A workpiece 4 having an end surface of the same shape, that is, a processing surface, is in contact with the upper surface of the grinding tool 2. The grinding tool 2 includes a power source 6 for generating a pulse current through a brush 7.
Connected to the anode.

In order to mount and hold the work 4, it is formed in a dish shape with an (−) electrode 13, which will be described later. The receiving tool 16 is provided under pressure. The rotating shaft 1 swings with respect to the workpiece 4. (-) Electrode 1
Reference numeral 3 is fixed to the wrench holder 16 via an insulator 14b. An insulator 14a is provided between each (-) electrode 9a to 9d.
, And the (-) electrodes 9a to 9d are insulated (see FIG. 5). Further, a terminal 12 for energizing a resistor 8 as a resistance member described later is fixed to the upper surface of each of the (-) electrodes 9a to 9d.

The resistor 8 is made of four kinds of materials having different electric conductivities, and the electric conductance increases from 8a to 8d (see FIG. 4). Further, it is held by the resistor holder 17. The resistor holder 17 is connected to the cathode of the power supply 6 that generates a pulse current. Further, the resistor holder 17 is pressed by the spring 10 along the kansushi 5 and does not rotate. One end of the spring 10 is fixed and pressed by a stopper 11 fixed to the screw 5. (−) The weak electric coolant is supplied to the gap e between the electrode 13 and the grinding tool 2 via a coolant nozzle 15 from a pump (not shown).

In the apparatus having the above-described configuration, first, the resistor 8a made of a material having a large electric resistance (low electric conductivity) is fixed by rotating the screw 5 so as to be near the rotation center of the grinding tool. The workpiece 4 is ground into a spherical surface by swinging the grinding tool 2 around a spherical center.

The resistor holder 1 connected to the cathode of the power source 6
The resistor 8 is connected through the resistor 7. Next, the (-) electrode 13
Through the terminal 12, a current matching the electric conductivity of each of the resistors 8a to 8d flows. (-) The electrode 13 rotates in a subordinate manner, but the resistor 8 does not rotate, so that a current corresponding to the electric conductivity of the resistor 8 flows in each wheel body in the radial direction of the grindstone.

Grinding tool 2 using weakly electric coolant as a medium
Is subjected to electrolytic dressing. At that time, each of the resistors 8a to 8d
As a result, a larger amount of current flows more easily toward the outer periphery of the grinding tool 2, and electrolysis is less likely to occur at the outer periphery due to the influence of the peripheral speed. Although the resistor 8 is divided into six parts, the division is made more accurately by further dividing. Further, when the shape of the grinding tool 2 is corrected, the resistor 8d having a high electric conductivity is moved to a portion where the electrolysis is to be strengthened,
Promotes electrolysis.

According to this embodiment, electrolytic dressing can be performed while maintaining the shape of the grinding tool, and further, the shape of the grinding tool can be corrected by the electrolytic dressing.

[0022]

Embodiment 2 FIGS. 6 and 7 show this embodiment. FIG. 6 is a cross-sectional view with a part omitted, and FIG. 7 is a cross-sectional view taken along line CC 'of FIG. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. In the lens grinding and polishing apparatus, a coil 20 as a resistance member wound with a conductive wire is connected to a cathode of a power source 6 from a D portion on the left end in the drawing and is cut at a E portion on the right end in the drawing (see FIG. 7). .
The coil 20 is set by the coil holder 21 so that the portion E is located near the center of the grinding tool 2. Further, the coil 20 is in contact with at least two or more terminals 12 and is energized. The terminal 12 and the (−) electrode 13
Is the same as the number of divisions.

In the apparatus having the above-described configuration, the coil 20 is set as described above, and the grinding tool 2 is swung spherically to grind the work 4 into a spherical surface. Next, the coil 20 is connected to the cathode of the electrode 6. Dependently rotating (-) electrode 13
Through the terminal 12, a current flows in inverse proportion to the number of turns of the coil from the D portion to its contact point. (-) The electrode 13 rotates in a subordinate manner, but the coil does not rotate, so that a current corresponding to the resistance value of the coil flows in each wheel body in the radial direction of the grindstone.

Grinding tool 2 using weakly electric coolant as a medium
Is subjected to electrolytic dressing. At this time, the current is more likely to flow toward the outer periphery of the grinding tool 2 and is canceled by the influence of the peripheral speed. Further, when the shape of the grinding tool 2 is corrected, the portion D of the coil 20 is moved to a portion where the electrolysis is to be strengthened, thereby promoting the electrolysis.

According to the present embodiment, the strength of electrolysis can be given only by the number of types of the resistors in the first embodiment, whereas in the present embodiment, the division of the terminal 12 ((-) electrode 13) is performed. The strength of electrolysis can be adjusted by the number, and the shape maintenance of the grinding tool becomes more accurate. Further, the shape correction becomes more accurate.

[0026]

Embodiment 3 FIGS. 8 and 9 show this embodiment. FIG. 8 is a sectional view with a part omitted, and FIG. 9 is a plan view of a (-) electrode. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. A swingable work holder 33, which has a dish shape for mounting and holding the work 4 and has a central portion engaged with a spherical portion of the tip 5 of the kansashi 5 which does not rotate in a rod shape, is provided under pressure. The (-) electrode 34 is set on the work holder 33 via the insulator 14b and the bearing 32. An insulator 14a is interposed between the (-) electrodes 34a to 34d and is insulated from each other (see FIG. 9). Each of the (-) electrodes 34a to 34d is made of four kinds of materials having different electric conductivity, and the electric conductivity increases as the (-) electrodes 34a to d change.

The stopper 11 is fixed to the screw 5, and the upper end of the spring 30 is fixed to the lower surface thereof. The lower end of the spring 30 is fixed to the (-) electrode holder 31. The (−) electrode 34 is pressed and held by the spring 30 and is prevented from rotating with respect to the center line of the wrench 5. (−) The weak electric coolant is supplied to the gap e between the electrode 34 and the grinding tool 2 via a coolant nozzle 15 from a pump (not shown).

In the device having the above-described structure, first, the (-) electrode 34a made of a material having a large electric resistance (low electric conductivity) is used.
The stopper 11 is loosened and adjusted so as to be close to the rotation center of the grinding tool 2, and the grinding tool 2 is swung spherically to adjust the workpiece 4.
Is ground into a spherical surface.

While the work 4 and the work holder 33 rotate in a subordinate manner during machining, since the (-) electrode 34 is connected to the work holder 33 via the bearing 32, the (-) electrode 34 is adjusted in advance. Fixed in position. The spring 30 presses the (−) electrode holder 31 so that the (−) electrode holder 31 follows the movement of the work holder 33 and the (−) electrode 34 with the sphere of the kansashi 5 as a fulcrum.

An electric current corresponding to the electric conductivity flows through each of the (-) electrodes 34a to 34d, and the grinding tool 2 is electrolytically dressed using a weakly conductive coolant as a medium. At this time, the (−) electrodes 34a to 34d cancel the current more easily toward the outer periphery of the grinding tool 2 and the influence of the peripheral speed. Although the (-) electrode is divided into six parts, it can be accurately canceled by further dividing. further,
When the shape of the grinding tool 2 is corrected, the (-) electrode 34d having a high electric conductivity is moved to a portion where the electrolysis is desired to be strengthened, thereby promoting the electrolysis.

According to this embodiment, a bearing is interposed between the work holder and the (-) electrode as compared with the first embodiment. Therefore, in addition to the same effect, even when rotating at high speed, the effect of suppressing the subordinate rotation of the work is small, and the present invention can be applied to high speed machining.

[0032]

Embodiment 4 FIGS. 10 to 12 show this embodiment.
Is a cross-sectional view with a part omitted, FIG. 11 is a plan view of a coil, and FIG. 12 is a plan view of a (-) electrode. In this embodiment, the same components as those of the third embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the lens grinding and polishing apparatus, a coil 41 wound with a conductive wire is pressed and held by a spring 30 and is fixed so as not to rotate. Further, the coil 41 is connected to the cathode of the power source 6 from the D portion on the left end of FIG.
The part has been cut. Further, the portion E of the coil 41 is adjusted to be near the center of the grinding tool 2. Also,
The coil 41 is in contact with at least two or more (−) electrodes 42 and is energized. The (−) electrode 42 is the insulator 1
4a (see FIG. 12).

In the apparatus having the above-described structure, the coil 41 is set as described above, and the grinding tool 2 is swung in a spherical center to grind the work 4 into a spherical surface. Coil 4 on cathode of power supply 6
1 is connected. The coil 41 and the (-) electrode 42 are energized, and the grinding tool 2 is subjected to electrolytic dressing using a weakly electric coolant as a medium.

At this time, the current value of the divided (−) electrode 42 is inversely proportional to the number of turns of the coil from the D portion of the coil 41 to its contact point. Therefore, the larger the current flows toward the outer periphery of the grinding tool 2, the more the current easily flows, and the current is canceled by the effect of the peripheral speed. Further, when correcting the shape of the grinding tool 2,
The part D of the coil 41 is moved to the part where the electrolysis is to be strengthened to promote the electrolysis.

According to this embodiment, the strength of electrolysis is given by the number of divisions of the (-) electrode 42 as in the second embodiment, and the shape of the grinding tool can be maintained more accurately. Further, the shape correction becomes more accurate. It can also be applied to high-speed machining.

[0036]

Embodiment 5 FIGS. 13 to 15 show this embodiment.
14 is a cross-sectional view partially omitted, FIG. 14 is a side view showing a connection state between the energizing member and the switch, and FIG. 15 is a side view showing a modified example of FIG. In this embodiment, the same components as those in the fourth embodiment are denoted by the same reference numerals, and the description thereof is omitted.
In the lens grinding / polishing apparatus, the insulator 50 is a rotating shaft 1
In addition, it is fixed to a polishing apparatus main body (not shown) separately from the kansashi 5. A current-carrying member 51 connected to the cathode of the power supply 6 is fixed to the insulator 50. The fixed position is located coaxially with the kansashi 5.

The switch 52 is in the form of a leaf spring and is pressed against the current-carrying member 51 and the insulator 50. One end of the switch 52 is fixed to the base of the rotating shaft 1 (not shown), and makes the same swinging motion as the grinding tool 2. Further, the switch 52 is set so that the outermost periphery of the (−) electrode 42 coincides with the center line of the rotating shaft 1 or at a position near the center line.
1 is set. The D portion of the coil 41 and the switch 52 are connected. As shown in FIG. 15, a roller 54 may be provided on the conducting member 51, and the switch 53 may be formed in a shape corresponding to the roller 54.

The apparatus having the above-described structure is configured such that the rotating shaft 1
Swings, and when the outermost periphery of the (−) electrode 42 comes near the center line of the rotating shaft 1, the conducting member 51 connected to the cathode of the power supply 6 and the switch 52 contact and conduct electricity, 2) The electrode 42 is connected to the cathode, and the grinding tool 2 is intermittently electrolytically dressed using a weakly electric coolant as a medium.

According to this embodiment, more accurate electrolytic dressing can be performed.

In this embodiment, the connection with the fourth embodiment is used. However, similar effects can be obtained with the other embodiments 1 to 3. In each embodiment, an example of processing a single concave lens has been described. However, the same effect can be achieved by using a convex lens, a multi-adhesive lens, or a multi-adhesive grinding wheel and polishing wheel. Further, the means for holding and swinging the lens is not limited to Kansashi. Further, the electrolysis power supply can be similarly performed using a pulse power supply and a DC power supply to which a DC component is added.

[0041]

As described above, according to the lens grinding apparatus of the present invention, electrolytic dressing can be performed while maintaining the shape of the grinding tool. Further, the shape of the grinding tool can be corrected by the electrolytic dressing.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating the present invention.

FIG. 2 is a sectional view taken along line X-X ′ of FIG. 1;

FIG. 3 is a cross-sectional view illustrating the first embodiment.

FIG. 4 is a sectional view taken along line A-A ′ of FIG. 3;

FIG. 5 is a sectional view taken along line B-B ′ of FIG. 3;

FIG. 6 is a sectional view showing a second embodiment.

7 is a sectional view taken along line C-C 'of FIG.

FIG. 8 is a sectional view showing a third embodiment.

FIG. 9 is a plan view showing a third embodiment.

FIG. 10 is a sectional view showing a fourth embodiment.

FIG. 11 is a plan view showing a fourth embodiment.

FIG. 12 is a plan view showing a fourth embodiment.

FIG. 13 is a sectional view showing a fifth embodiment.

FIG. 14 is a side view showing the fifth embodiment.

FIG. 15 is a side view showing the fifth embodiment.

FIG. 16 is a sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotary axis 2 Grinding tool 3 Work holder 4 Work 5 Kansashi 6 Power supply 7 Brush 8 Coolant nozzle 9 (-) electrode 10 Insulator

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) B23H 5/00, 5/10 B23H 7/14 B24B 13/00-13/06 B24B 53/00

Claims (3)

(57) [Claims] 1. A conductive grinding tool applied to an anode is rotated, and an electrode arranged so as to keep a predetermined distance from a processing surface of the conductive grinding tool is applied to a cathode. In a lens grinding apparatus for relatively oscillating a conductive grinding tool and a work in a state where a weakly conductive coolant is interposed between the electrodes, the electrode is a ring-shaped provided on the outer periphery of the work, and is electrically operated in a circumferential direction. A lens grinding device comprising a plurality of members having different electrical conductivity. 2. A conductive grinding tool applied to an anode is rotated, and an electrode arranged so as to keep a predetermined distance from a processing surface of the conductive grinding tool is applied to a cathode. In a lens grinding device that relatively oscillates a conductive grinding tool and a workpiece with a weakly conductive coolant interposed between them, the electrical conductivity differs in the circumferential direction or the resistance changes analogously in the circumferential direction A lens grinding device comprising: a resistance member; and a ring-shaped electrode provided on an outer periphery of the work and in contact with the resistance member. 3. The lens grinding device according to claim 1, further comprising a switch that conducts electricity only when the center of the conductive grinding tool or its vicinity is located at the outermost periphery of the electrode. apparatus.