JPH09262750A - Method and device for grinding aspheric surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a machining time and the occurrence of wear of a grinding wheel by a method wherein a grinding wheel spindle part and a work spindle part are relatively moved in the direction of the shaft lengths of the rotary shafts thereof and by pressing a work against a form grinding wheel, a contact between the form grinding wheel and the work forms a linear contact. SOLUTION: In such a state to rotate a form grinding wheel 29 and a glass lens 43, a work slide table part 19 is moved in parallel to the rotary shaft of a work spindle part 17 by a DC servo motor 23 and a feed screw 25. A grinding wheel shift table part 33 is moved by a stepping motor 37 and a feed screw 39 and a glass lens 43 is forcibly pressed against the form grinding wheel 29. This constitution transfers the aspherical shape of the form grinding wheel 29 to a glass lens 43 and forms the glass lens 43 into an aspherical shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aspherical surface grinding method and an aspherical surface grinding apparatus for processing an aspherical surface of a lens or a mold using a grindstone.

[0002]

2. Description of the Related Art Generally, many aspherical surfaces used for lenses and the like in the optical field are axisymmetric aspherical surfaces, and conventionally such aspherical surfaces have been created by processing by trajectory control by a numerical control processing machine. Then, conventionally, as a processing method by a numerically controlled processing machine, for example, three methods as shown in FIG. 4 are known.

In the first method, as shown in FIG. 4 (a), while the workpiece 1 is rotated around the Y axis, a grindstone 2 having an R-shaped grinding surface is desired in the X and Y planes. It is made to move along the aspherical shape curve of, and can be processed by a processing machine of simultaneous X, Y biaxial control. However, in such simultaneous biaxial control, the processing points 2a, 2b of the grindstone 2 are
Is different depending on the machining position, so the whetstone 2 has a perfect arc R
Otherwise, an error will occur in the aspherical shape.

A conventional two-axis control type aspherical surface grinding machine is, for example, "Nikkei Mechanical 19".
The aspherical surface grinding machine described in "January 28, 1985, p. 104" is known. In the second method, as shown in FIG. 4 (b), in order to compensate for the drawback of the simultaneous biaxial control of FIG. 4 (a), the θ axis is added and the grindstone 2 or the workpiece is processed by the θ axis. 1 is turned so that the machining point 2c of the grindstone does not change during the machining movement, and is performed using a simultaneous three-axis control machining machine.

As an example of such a three-axis control type aspherical surface grinding machine, there is a conventional method such as "Ultra Precision Production Technology System".
The aspherical surface grinding machine described in "Volume 2, Practical Technology, p. 208" is known. The third method is, as shown in FIG. 4C, rotating the work piece 1 around the Y axis and, within a plane orthogonal to the rotation axis of the work piece 1, having a radius r. Three
Is rotated and the outer peripheral surface of the grindstone 3 is moved along a predetermined aspherical cross-sectional shape to create an aspherical cross-sectional shape. In this case, the radius r of the grindstone 3 is the accuracy of the rotation axis of the grindstone 3. Depends on.

[0006]

However, in the conventional aspherical surface grinding machine, since the grindstones 2 and 3 are processed along the aspherical surface shape by the trajectory control, the grindstones 2 and 3 are processed.
The portion to be contacted with the workpiece 1 to be processed becomes a spot contact, and as a result, the processing takes time and the portion to be contacted with the grindstones 2 and 3 is limited, so that the grindstones 2 and 3 wear quickly. There was a problem.

In addition, two axes of X and Y or 3 including θ
Since the error of the axis is directly reflected in the error of the shape of the workpiece 1, there is a problem that highly accurate motion performance and control performance are required to obtain a highly accurate shape. The present invention has been made to solve such conventional problems, and provides an aspherical surface processing method and an aspherical surface grinding device that can significantly reduce the processing time and the wear of the grindstone with a simple configuration. The purpose is to

[0008]

According to the aspherical surface grinding method of the present invention, the axis of rotation of the grindstone spindle for rotating the grindstone and the axis of rotation of the work spindle for rotating the workpiece are positioned in parallel. The grindstone spindle portion, a grindstone in which a grindstone surface having a shape corresponding to one half of the symmetry axis of the axisymmetric aspherical surface to be formed on the workpiece is formed is mounted,
In a state in which the general-purpose grindstone and the workpiece are rotated, the grindstone spindle portion and the work spindle portion are relatively moved in the axial direction of these rotary shafts, and the workpiece is attached to the grindstone surface of the general-type grindstone. Is pressed to transfer the shape of the grindstone surface of the full-form grindstone to the workpiece.

The aspherical surface grinding method according to a second aspect is the aspherical surface grinding method according to the first aspect, in which the grindstone spindle portion and the work spindle portion are relatively moved at a predetermined speed in the axial direction of these rotary shafts. It is characterized by Claim 3
The aspherical surface grinding method according to claim 1 is the aspherical surface grinding method according to claim 1, wherein the grindstone spindle portion and the work spindle portion are formed on the grindstone surface of the general-purpose grindstone in the axial direction of the rotary shafts thereof. It is characterized by relative movement so that the pressing force of the object becomes constant.

According to a fourth aspect of the present invention, there is provided an aspherical surface grinding machine, wherein a work spindle part having a rotary shaft for rotating the work piece about its center, and the work spindle part are mounted on the work spindle part. Of the work slide table, which is movable in the axial direction, and a grindstone, and a grindstone spindle having a rotation axis which is an axis passing through the center of the grindstone and parallel to the moving direction of the work slide table. And a grindstone shift table part on which the grindstone spindle part is mounted and which is movable in a direction orthogonal to the moving direction of the work slide table part.

According to a fifth aspect of the present invention, there is provided an aspherical surface grinding machine, wherein a work spindle part having a rotary shaft for rotating the work piece about its center, and the work spindle part are mounted on the work spindle part. And a work slide table part movable in the axial direction of the work spindle part, and the work spindle part is interposed between the work spindle part and the work slide table part. A constant pressure slide mechanism that presses and moves with a grindstone, and a grindstone spindle section that holds the full-scale grindstone and that has a rotation axis that is positioned parallel to the movement direction of the work slide table section and that passes through the center of the gross-shape grindstone. And a grindstone shift table section on which the spindle section is mounted and which is movable in a direction orthogonal to the movement direction of the work slide table section. And wherein the Rukoto.

An aspherical surface grinding apparatus according to a sixth aspect is the aspherical surface grinding apparatus according to the fifth aspect, wherein the work pressure spindle mechanism is fixed and the constant pressure slide mechanism moves in the axial direction of the rotary shaft of the work spindle section. It is characterized by having a possible linear guide and an actuator which is fixed to the work slide table section and presses the linear guide toward the forming tool grindstone.

(Operation) In the aspherical surface grinding method according to claim 1,
Arrange the rotary axis of the grindstone spindle and the rotary axis of the work spindle parallel to each other, and attach the grooving stone to the grindstone spindle section and the work piece to the work spindle section. While rotating, the grindstone spindle part and the work spindle part are moved relative to each other in the axial direction of these rotary shafts, and the workpiece is pressed against the grindstone so that the grindstone surface of the grindstone is not The spherical shape is transferred to the workpiece, and an aspherical shape is formed on the workpiece.

In the aspherical surface grinding method according to the second aspect of the present invention, the grindstone spindle portion and the work spindle portion are forcibly moved relative to each other in the axial direction of these rotary shafts at a predetermined speed, and relatively coarse forced grinding is performed. Done. According to the aspherical surface grinding method of claim 3, the grindstone spindle portion and the work spindle portion are arranged relative to each other in the axial direction of these rotary shafts so that the pressing force of the workpiece against the grindstone surface of the full-scale grindstone is constant. It is moved, and constant pressure grinding with relatively high accuracy is performed.

In the aspherical surface grinding machine according to a fourth aspect of the present invention, the rotary shaft of the grindstone spindle portion and the work spindle portion are arranged parallel to each other, and the full-form grindstone is mounted on the grindstone spindle portion.
After the work piece is mounted on the work spindle part, the work slide table part is moved parallel to the rotation axis of the work spindle part while rotating the work piece grinding stone and the work piece, and the work piece is attached to the work piece grinding stone. By forcibly pressing, the aspherical shape of the full-form grindstone is transferred to the workpiece, and the aspherical shape is formed on the workpiece.

In the aspherical surface grinding machine according to a fifth aspect of the present invention, the work spindle unit is moved by the constant pressure slide mechanism so that the pressing force of the workpiece on the grindstone surface of the full-scale grindstone becomes constant.
Constant pressure grinding with relatively high precision is performed. In the aspherical grinding device of the sixth aspect, the linear guide is pressed by the actuator, and the work spindle part is moved so that the pressing force of the workpiece on the grindstone surface of the full-scale grindstone is constant.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 shows a first embodiment of an aspherical surface grinding apparatus of the present invention. In this aspherical surface grinding apparatus, a work part 11 and a grindstone part 13 constitute a main part.
A work spindle unit 17 having a rotation shaft (not shown) that rotates the work 15 is arranged in the work unit 11.

The work spindle portion 17 is a spindle with a built-in motor, and the work slide table portion 1 is provided.
9 is fixed. Work slide table section 19
Are movably arranged on the linear guide 21.
This work slide table section 19 is provided with the linear guide 2
1 is used as a guide, and is moved by the DC servo motor 23 and the feed screw 25.

The position of the work slide table portion 19 can be confirmed by the encoder 27 mounted on the DC servo motor 23 and the leads of the feed screw 25. A grindstone 29 for grinding the workpiece 15 and a grindstone spindle portion 31 for holding and rotating the grindstone 29 are arranged in the grindstone 13.

The grindstone spindle section 31 is a spindle with a built-in motor and is fixed to the grindstone shift table section 33. The grindstone shift table portion 33 is movably arranged on the linear guide 35. The grindstone shift table portion 33 is moved by a stepping motor 37 and a feed screw 39 using the linear guide 35 as a guide.

The position of the grindstone shift table 33 can be confirmed by the digital micrometer 41. Hereinafter, the operation when the aspherical surface of the glass lens is processed by the above-described aspherical surface grinding device will be described. First, the work 15 as shown in FIG. 2A is fixed to the work spindle portion 17.

The work 15 is formed by joining the glass lens 43, which is the work piece, to the jig 45 with beeswax.
Then, the work 15 is fixed to the work spindle 17 by the bolt 47 via the jig 45. On the other hand, as shown in FIG. 2 (b), the full-scale grindstone 29 has one side of the axis of symmetry of the axisymmetric aspheric surface to be formed on the glass lens 43 on the surface facing the glass lens 43 as the workpiece. A grindstone surface 29a having a shape corresponding to the half portion is formed, and
Is screwed to the grindstone spindle portion 31 with a bolt 49.

In the aspherical surface grinding machine of this embodiment, rough grinding is mainly performed by forced grinding. First, the relationship between the overall-shaped grindstone 29 and the contact surface of the work 15 is adjusted by moving the grindstone shift table portion 33. Next, the grindstone spindle portion 31 and the work spindle portion 17 are rotated.

In this state, the DC servo motor 23
As a result, the work slide table portion 19 is moved at a constant speed to perform forced grinding. Table 1 below shows the processing conditions at this time.

[Table 1] Under the processing conditions shown in Table 1, for a processing amount of several hundreds μm to several mm in terms of the center thickness of the glass lens 43, processing with a shape accuracy within several μm is performed in an extremely short time compared with the conventional method. I was able to.

In the aspherical surface grinding machine configured as described above, the work slide table section 19 is moved in parallel with the rotation axis of the work spindle section 17 while the shaping wheel 29 and the glass lens 43 are rotated. By forcibly pressing the glass lens 43 against the all-round grindstone 29, the aspherical shape of the all-round grindstone 29 is transferred to the glass lens 43.
It is possible to easily perform relatively coarse forced grinding.

In the aspherical surface grinding method described above, the grindstone spindle portion 31 and the work spindle portion 17 are moved relative to each other in the axial direction of the rotary shafts thereof while the shaping wheel 29 and the glass lens 43 are rotated. Let's make a pattern grindstone 29
By pressing the glass lens 43 against the
Since the aspherical shape of 9 is transferred to the glass lens 43 and the aspherical shape is formed on the glass lens 43, the contact between the full-scale grinding stone 29 and the glass lens 43 comes into line contact, and the processing time and the abrasion of the grinding stone are reduced. It can be significantly reduced compared to the conventional one.

Further, in the aspherical surface grinding method described above, since the grindstone spindle portion 31 and the work spindle portion 17 are forcibly moved relative to each other in the axial direction of these rotary shafts at a predetermined speed, they are relatively moved. Forced grinding with coarse accuracy can be easily performed. FIG. 3 shows a second embodiment of the aspherical surface grinding device of the present invention. In this aspherical surface grinding device, the work spindle part 17 is provided between the work spindle part 17 and the work slide table part 19. A constant pressure slide mechanism 51 is arranged to press and move with a predetermined pressure in the axial direction of the rotary shaft of the spindle unit 17.

The constant pressure slide mechanism 51 has a linear guide 53 to which the work spindle 17 is fixed. The linear guide 53 is the work slide table 1
It is guided by a guide table 54 which is fixed to 9 and is movable in the axial direction of the rotary shaft of the work spindle unit 17.

Further, an air cylinder 55, which is an actuator for pressing the linear guide 51 toward the shaping wheel 29 side, is fixed to the work slide table section 19. It should be noted that, except for the above-mentioned portion, it has the same configuration as the aspherical surface grinding apparatus shown in FIG. 1, and therefore, the same portions will be denoted by the same reference numerals and detailed description thereof will be omitted. The aspherical surface grinding machine of this embodiment mainly performs precise grinding by constant pressure grinding.

First, the relationship between the full-form grindstone 29 and the contact surface of the work 15 is adjusted by the movement of the grindstone shift table portion 33. Next, the grindstone spindle portion 31 and the work spindle portion 17 are rotated. Then, in this state, the air guide 55 is used to move the linear guide 53 to the full-form grindstone 29.
Constant pressure grinding is performed by pressing and moving to the side with a predetermined constant pressure.

Table 2 below shows the processing conditions at this time.

[Table 2] Under the processing conditions shown in Table 2, a sufficient shape accuracy of several μm was obtained for a processing amount of several tens μm in terms of the center thickness of the glass lens 43. In the aspherical surface grinding machine configured as described above, constant pressure grinding is performed so that the pressing force of the full-form grindstone 29 against the glass lens 43 is constant, so that highly accurate grinding can be easily performed. it can.

Further, in the above-mentioned aspherical surface grinding device, the linear guide 53 to which the work spindle 17 is fixed is pressed by the air cylinder 55, so that the glass lens 43 is attached to the grindstone surface 29a of the full-form grindstone 29. The work spindle unit 17 can be easily moved so that the pressing force becomes constant. Further, in the above-described aspherical surface grinding method, constant pressure grinding is performed so that the pressing force of the full-form grindstone 29 against the glass lens 43 is constant, so that highly accurate grinding can be easily performed.

In the above embodiment, the glass lens 43 is applied to the workpiece, but the present invention is not limited to this embodiment.
It may be a mold for molding a plastic lens or an aspherical lens. Further, as long as it is an axially symmetric aspherical lens, it is not limited to a convex lens, and a concave lens may be used.

[0034]

As described above, in the aspherical surface grinding method according to the first aspect of the present invention, the grindstone spindle portion and the work spindle portion are provided with the axes of their rotating shafts while the full-scale grindstone and the workpiece are rotated. By relatively moving in the long direction and pressing the work piece against the forming tool, the aspherical shape of the forming tool is transferred to the work piece, and the aspherical shape is formed on the work piece. The contact between the grindstone and the work piece comes into contact with the line, and the processing time and the wear of the grindstone can be significantly reduced as compared with the conventional case.

In the aspherical surface grinding method according to the second aspect of the present invention, since the grindstone spindle portion and the work spindle portion are forcibly moved relative to each other in the axial direction of these rotary shafts at a predetermined speed, the precision is relatively high. Rough forced grinding can be easily performed. In the aspherical surface grinding method according to the third aspect, constant pressure grinding is performed so that the pressing force of the full-scale grindstone on the workpiece is constant, so that highly accurate grinding can be easily performed.

In the aspherical surface grinding machine according to a fourth aspect of the present invention, the work slide table is moved parallel to the rotation axis of the work spindle while the general-purpose grindstone and the workpiece are being rotated, so that the total-form grindstone is processed. By forcibly pressing the object, the aspherical shape of the full-scale grindstone is transferred to the object to be processed, so that relatively precise forced grinding can be easily performed. In the aspherical surface grinding machine according to the fifth aspect, constant pressure grinding is performed so that the pressing force of the full-form grindstone on the workpiece is constant, so that highly accurate grinding can be easily performed.

In the aspherical surface grinding machine according to the sixth aspect of the present invention, since the linear guide to which the work spindle is fixed is pressed by the actuator, the pressing force of the workpiece on the grindstone surface of the general-purpose grindstone becomes constant. Thus, the work spindle part can be easily moved.

[Brief description of drawings]

FIG. 1 is a top view showing a first embodiment of an aspherical grinding device of the present invention.

FIG. 2 is a cross-sectional view showing configurations of the work and the full-scale grindstone of FIG.

FIG. 3 is a side view showing a second embodiment of the aspherical surface grinding device of the present invention.

FIG. 4 is a sectional view showing a conventional aspherical surface grinding method.

[Explanation of symbols]

 11 work part 13 grindstone part 15 work 17 work spindle part 19 work slide table part 29 general-purpose grindstone 29a grindstone surface 31 grindstone spindle part 33 grindstone shift table part 51 constant pressure slide mechanism 53 linear guide 55 air cylinder

Claims (6)

[Claims] 1. A rotation axis of a grindstone spindle section for rotating a grindstone and a rotation axis of a work spindle section for rotating a workpiece should be positioned in parallel with each other, and the grindstone spindle section should be formed on the workpiece. A grindstone having a grindstone surface having a shape corresponding to one half of an axis of symmetry of an axisymmetric aspherical surface is mounted, and the grindstone spindle portion and the workpiece are rotated with the grindstone and the workpiece being rotated. The spindle unit is relatively moved in the axial direction of these rotary shafts, the work piece is pressed against the grindstone surface of the general-purpose grindstone, and the shape of the grindstone surface of the general-type grindstone is transferred to the work object. An aspherical surface grinding method characterized by the above. 2. The aspherical surface grinding method according to claim 1, wherein the grindstone spindle part and the work spindle part are relatively moved at a predetermined speed in the axial direction of the rotary shafts thereof. Method. 3. The aspherical surface grinding method according to claim 1, wherein the grindstone spindle portion and the work spindle portion are arranged on the grindstone surface of the general-purpose grindstone in the axial direction of their rotary shafts. An aspherical surface grinding method, characterized in that relative movement is performed so that a pressing force becomes constant. 4. A work spindle unit having a rotation shaft for rotating the center of an object to be processed as an axis, and the work spindle unit mounted on the work spindle unit and movable in the axial direction of the rotation shaft of the work spindle unit. A work slide table portion, a grindstone spindle portion which holds a shaving wheel and which is positioned in parallel to the moving direction of the work slide table portion and which has an axis passing through the center of the skeleton grinding wheel as a rotation axis, and the grindstone spindle portion. An aspherical surface grinding machine, comprising: a grindstone shift table portion that is placed and is movable in a direction orthogonal to the movement direction of the work slide table portion. 5. A work spindle unit having a rotation shaft for rotating the center of the work piece as an axis, and the work spindle unit is mounted and movable in the axial direction of the rotation shaft of the work spindle unit. A work slide table section, and a constant pressure slide mechanism interposed between the work spindle section and the work slide table section for pressing and moving the work spindle section with a predetermined pressure in the axial direction of the rotation axis of the work spindle section. A grindstone spindle unit that holds a general-purpose grindstone and that is positioned parallel to the moving direction of the work slide table and that has an axis passing through the center of the general-type grindstone as a rotation axis; and mounting the grindstone spindle unit, And a grindstone shift table part movable in a direction orthogonal to the moving direction of the work slide table part. Surface grinding apparatus. 6. The aspherical surface grinding apparatus according to claim 5, wherein the constant pressure slide mechanism includes a linear guide to which the work spindle unit is fixed, and which is movable in an axial direction of a rotation shaft of the work spindle unit. An aspherical surface grinding device, comprising: an actuator that is fixed to a slide table portion and presses the linear guide toward the full-form grindstone.