JP2002239887A - Polygonal workpiece grinding method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shortly, sharply and precisely process the edge of a polygonal workpiece. SOLUTION: A grinding wheel 3 is reciprocated in an X-axial direction while rotating the workpiece 2 around a C-axis in one direction, for grinding one plane 2a of the workpiece 2. After grinding an edge P at the terminal of the plane 2a, the grinding wheel 3 is isolated from the workpiece 2. The grinding wheel 3 is reciprocated in a region in no contact with the workpiece 2 and the workpiece 2 is continuously rotated in the same direction. At this time, the grinding wheel 3 is moved with respect to the edge P while drawing an approximately elliptical locus swelling to the outside. At a position where the contact plane of the grinding wheel 3 corresponds to the next plane 2b of the workpiece 2, the grinding wheel 3 is put in contact with the edge P at the starting end of the next plane 2b. Then, the grinding wheel 3 is reciprocated while continuously rotating the workpiece 2 in the same direction, for grinding the next plane 2b of the workpiece 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for grinding a plurality of planes of a polygonal workpiece attached to a spindle with a grindstone which can be moved toward and away from the spindle.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a polygonal workpiece 2 is mounted on a spindle 1, and the spindle 1 is controlled around a C axis.
In synchronization with this, the wheel head (not shown) is controlled in the X-axis direction,
After grinding one plane 2a of the workpiece 2 with the grinding wheel 3 supported by the grinding wheel base, the next plane 2 is passed through the edge P of the corner portion.
A method of continuously grinding b is known. here,
As shown in FIG. 6, the grindstone 3 always contacts the workpiece 2 and moves along an arc locus having a radius R (grindstone diameter / 2) around the edge P as shown in FIG.

[0003] Conventionally, as shown in FIG.
After grinding one plane 2a (ab), the grindstone 3 is released from the edge P by a predetermined distance L at the corner (c), and the workpiece 2 is moved from the position where the edge P has passed the grinding point of the grindstone 3. There is known a method of inverting (d-e), positioning the grindstone 3 at the edge P, and subsequently grinding the next plane 2b. Here, the grindstone 3 once moves away from the workpiece 2 and moves along a circular locus as shown in FIG. 8 or a linear locus as shown in FIG. 9 in the non-contact area.

[0004]

However, according to the former grinding method, since the grinding wheel 3 contacts the edge P for a long time while moving along the arc locus, the data jump between the division points for determining the arc locus. For example, there is a problem that the edge P is easily sagged due to, for example, the blade portion of the punching tool cannot be sharply machined. On the other hand, in the latter grinding method, sagging hardly occurs when the grinding wheel 3 is released from the edge P. However, not only is there a waste of time for reversing the workpiece 2 at the time of positioning the grinding wheel 3, but also the time of reversing There was a problem that machining accuracy was reduced by lost motion.

It is an object of the present invention to provide a grinding method and apparatus capable of sharply and precisely processing edges of a polygonal workpiece in a short time.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a grinding method according to the present invention is a method for grinding a plurality of planes of a polygonal workpiece attached to a spindle with a grindstone capable of coming and going with respect to the spindle. A first step of reciprocating the grindstone while rotating the work piece in one direction to grind one plane of the work piece,
A second step of separating the grinding wheel from the workpiece after grinding the terminal edge of the plane, and a third step of reciprocating the grinding wheel in a non-contact area with the workpiece and continuously rotating the workpiece in the same direction. And a fourth step of bringing the grindstone into contact with the starting edge of the next plane at a position where the tangent plane of the grindstone and the next plane of the workpiece coincide with each other, and reciprocating the grindstone while continuously rotating the workpiece in the same direction And a fifth step of grinding the next plane of the workpiece.

Here, in order to move the grindstone in a non-contact area with the workpiece in a short time and smoothly contact the starting edge of the next plane, the grinding wheel is moved with respect to the edge of the workpiece in the third step. It is preferable to move along a substantially elliptical locus expanding outward.

In the third step, a point a separated by a predetermined amount in the extension direction from the previous plane centering on the edge of the workpiece and a point b separated by a predetermined amount in the extension direction from the next plane
And the intersection of a straight line passing through point a and parallel to the next plane and a straight line passing through point b and parallel to the destination plane is determined. May be obtained, and the grindstone may be moved around the end point of each straight line.

On the other hand, a grinding apparatus according to the present invention is an apparatus for grinding a plurality of planes of a polygonal workpiece mounted on a spindle with a grindstone capable of moving toward and away from the spindle. A storage unit for storing processing conditions including the processing conditions, a setting unit for setting a relief amount when the grinding wheel is separated from the edge of the workpiece, and creating positioning data of the grinding wheel with respect to the workpiece based on the processing conditions and the relief amount; It is composed of a positioning data creating unit for obtaining a grinding wheel movement trajectory substantially parallel to the plane of the object and bulging outward with respect to the edge, and a control unit for controlling the driving means of the spindle and the grinding wheel according to the positioning data.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a grinding apparatus according to this embodiment. The spindle 1 is supported by a headstock 11 and is rotated around a C axis by a motor (not shown).
A gripping device 12 is attached to the tip of the main shaft 1, and a rectangular workpiece 2 is attached to the gripping device 12, for example. The grindstone 3 is supported on a grindstone table 13, and the grindstone table 13 is
4 reciprocates in the X-axis direction via the feed shaft 15, that is, in the direction approaching and separating from the main shaft 1.

The electrical control system of the grinding device includes a machining condition storage unit 21 for storing various machining conditions including the shape data of the workpiece 2 and the diameter of the grinding wheel 3, and separating the grinding wheel 3 from the edge of the workpiece 2. Amount setting part 2 for setting the amount of relief when
2 are provided. The electric control system is provided with a positioning data creation unit 23 and a control unit 24. The data creation unit 23 creates the positioning data of the spindle 1 and the grinding wheel head 13 based on the machining conditions and the relief amount, and 2, a grinding wheel movement locus (see FIG. 3) which is substantially parallel to each plane and bulges outward with respect to the edge is obtained, and the control unit 24 drives the main shaft 1 via the C-axis drive unit 25 according to the positioning data. Controls the motor,
The drive motor 14 of the grinding wheel head 13 is controlled via the X-axis drive unit 26.

Next, a grinding method according to this embodiment will be described with reference to FIGS. FIG. 2 shows a method of grinding two adjacent planes 2a and 2b of the workpiece 2, but the same method is applied to other planes.
In grinding the workpiece 2, first, as shown in FIG. 1A, the workpiece 2 is rotated in one direction around the C axis, and in synchronization with this, the grindstone 3 is reciprocated in the X axis direction. One plane 2 a of the workpiece 2 is ground by the grindstone 3. At this time, the grindstone 3 has the C
According to the -X data, as shown in FIG. 3, the workpiece 2 moves along a trajectory parallel to the plane 2a.

Next, as shown in FIG.
After grinding the edge P at the end of the plane 2a, the grindstone 3 is separated from the workpiece 2 by a preset relief amount L. Next, as shown in FIGS. 3C to 3E, the grindstone 3 is reciprocated in a region not in contact with the workpiece 2, and the workpiece 2 is continuously rotated in the same direction as before. . At this time, as shown in FIG.
Is moved in a short time along a substantially elliptical locus bulging outward. This elliptical trajectory is obtained in the positioning data creating unit 23 by the following method.

That is, as shown in FIG. 4, first, a point a, which is separated from the plane 2a at the center of the edge 2 of the workpiece 2 by a distance L in the extending direction from the plane 2a at the front of the workpiece 2, and the next plane 2
An arc connecting the point b which is separated from the point b by an escape amount L in the extension direction is obtained. Next, the intersection Q of the straight line passing through the point a and parallel to the next plane 2b and the straight line passing through the point b and parallel to the destination plane 2a
(The point of symmetry of the edge P with respect to the straight line ab) is obtained. Subsequently, the length of the grinding stone 3 from the equal division point D on the arc through the intersection Q is
Are obtained. Then, the end point O of each straight line is recognized as the center position of the grindstone 3, and the elliptic curve connecting the points O is determined as the movement locus of the grindstone 3. Thereafter, a value x obtained by subtracting the radius R of the grindstone 3 from the length of a line segment connecting the center O of the grindstone 3 and the center C of the workpiece 2 is obtained for each rotation phase of the spindle 1, and the positioning data of the C axis and the X axis is obtained. Create

At the end of the elliptical trajectory, the grinding wheel 3 is positioned at a position where its tangent plane coincides with the extension of the next plane 2b of the workpiece 2, and in this state, as shown in FIG. A smooth contact is made with the edge P at the beginning of the plane 2b.
Thereafter, as shown in (g), the workpiece 2 is continuously rotated in the same direction, and the grindstone 3 is reciprocated. The next flat surface 2b of the workpiece 2 is ground by the grindstone 3. Therefore, when grinding the corner, the workpiece 2 is turned over,
There is no need to stop the grindstone 3 once, and the edge P of the workpiece 2 can be sharply and accurately processed in a short time.

It should be noted that the present invention is not limited to a quadrangular workpiece, but can also be applied to a triangular, pentagonal, hexagonal, or a workpiece having a large number of corners. In addition, the shape and configuration of each part may be appropriately changed and embodied without departing from the spirit of the present invention.

[0017]

As described above in detail, according to the first and fourth aspects of the present invention, the polygonal workpiece is continuously rotated in one direction, and after grinding the end edge of one plane, the grinding wheel is removed. Separated from the workpiece, the grindstone is brought into contact with the starting edge of the next plane at the position where the tangent plane of the grinding wheel and the next plane of the workpiece match, so that the edge of the workpiece is sharply and accurately processed in a short time It has an excellent effect that it can be done.

According to the second and third aspects of the present invention, the whetstone moves on a curve bulging outward with respect to the edge of the workpiece, so that the whetstone can be moved in a non-contact area in a short time.
There is an effect that the edge can be smoothly contacted.

[Brief description of the drawings]

FIG. 1 is a schematic view of a grinding apparatus showing one embodiment of the present invention.

FIG. 2 is an explanatory view of a grinding method using the apparatus of FIG.

FIG. 3 is a schematic diagram showing a movement locus of a grindstone in the grinding method of FIG. 2;

FIG. 4 is a schematic diagram illustrating a method for obtaining an elliptical portion in the locus of FIG. 3;

FIG. 5 is an explanatory view showing a conventional grinding method.

FIG. 6 is a schematic diagram showing a movement locus of a grindstone in the grinding method of FIG. 5;

FIG. 7 is an explanatory view showing another conventional grinding method.

FIG. 8 is a schematic diagram showing a movement locus of a grindstone in the grinding method of FIG. 7;

FIG. 9 is a schematic diagram showing another movement locus of a grindstone in the grinding method of FIG. 7;

[Explanation of symbols]

1. Spindle, 2. Workpiece, 2a, 2b, Plane, 3.
・ Whetstone, 21 ・ ・ Processing condition storage unit, 22 ・ ・ Relief amount setting unit, 23 ・ ・ ・ Positioning data creation unit, 24 ・ Control unit, P ・ ・ Edge.

Claims (4)

[Claims] 1. A method of grinding a plurality of planes of a polygonal workpiece mounted on a spindle with a grindstone capable of coming and going with respect to the spindle, wherein the grindstone is reciprocated while rotating the workpiece in one direction. A first step of grinding one plane of the workpiece, a second step of separating the grinding wheel from the workpiece after grinding the end edge of the plane, and reciprocating the grinding wheel in a non-contact area with the workpiece. ,
A third step of continuously rotating the workpiece in the same direction, a fourth step of bringing the grinding wheel into contact with the starting edge of the next plane at a position where the tangent plane of the grinding wheel coincides with the next plane of the workpiece, Grinding the next plane of the workpiece by reciprocating the grindstone while continuously rotating the workpiece in the same direction, and a fifth step of grinding the polygonal workpiece. 2. The method for grinding a polygonal workpiece according to claim 1, wherein in the third step, the grindstone moves along a substantially elliptical locus bulging outward with respect to the edge of the workpiece. 3. In a third step, a point a is separated from the plane by a predetermined amount in the extension direction with respect to the edge of the workpiece in the extension direction.
An arc connecting the point b and the point b separated from the next plane by a predetermined distance in the extension direction is obtained, and an intersection of a straight line passing through the point a and parallel to the next plane and a straight line passing through the point b and parallel to the destination plane is obtained. 3. The grinding of a polygonal workpiece according to claim 1, wherein a plurality of straight lines having a length equal to the radius of the grindstone are determined from the points on the arc through the intersection, and the grindstone moves around the end point of each straight line. Method. 4. An apparatus for grinding a plurality of planes of a polygonal workpiece attached to a spindle with a grindstone capable of coming and going with respect to the spindle, and storing machining data including workpiece shape data and grinding wheel diameter. And a setting unit for setting a relief amount when separating the grindstone from the edge of the workpiece, and creating positioning data of the grindstone with respect to the workpiece based on the machining conditions and the relief amount, and substantially parallel to the plane of the workpiece. A polygonal workpiece grinding apparatus comprising: a positioning data creating unit for obtaining a grinding wheel movement trajectory that becomes a substantially elliptical bulging outward with respect to an edge; and a control unit that controls driving means of the spindle and the grinding wheel according to the positioning data.