JPS63216661A - Cylindrical grinding method - Google Patents

Abstract

PURPOSE:To prevent any drop in work strength from occurring, by tilting an axis of rotation of a grinding wheel as far as an angle theta to that of the work, and grinding it in a way of setting this angle theta, work peripheral speed and traverse speed to the specified relationship. CONSTITUTION:A work 10 of glass and ceramics or the like and a grinding wheel 20 are reversed with each other, while a wheel spindle stock 21 is fed into plunge cutting in parallel with an axis of rotation O of the work 10, and cylindrical grinding is carried out after traversing the work 10. In this case, an axis of rotation P of the grinding wheel 20 is tilted as far as an angle thetato the axis of rotation O of the work 10 around a line segment (m) connecting both these axes P and O together at a right angle, and work peripheral speed (v), wheel peripheral speed V and traverse speed (a) to this angle theta should be set to (¦Vcostheta-v¦)/(¦Vsintheta+a¦)<=tan30 deg., thus grinding takes place. If so, only a crack with a tilt of less than 30 deg. to this axis of rotation is entered in the work, so that such a possibility that strength for work's bending or the like is lowered by grinding is preventable.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a cylindrical grinding method that does not reduce the strength of a workpiece after grinding.

<Prior Art> Conventionally, the workpiece was cylindrically ground by rotating the workpiece and the grinding wheel in opposite directions around axes parallel to each other.

<Problems to be Solved by the Invention> When such cylindrical grinding is performed, cracks occur in the workpiece in the direction of rotation, resulting in a significant decrease in bending strength. In particular, there is a risk that brittle materials such as glass and ceramics will break, so it was necessary to remove the crank by finishing processing such as lapping.

Means for Solving Problems> The present invention tilts the rotational axis of the grinding wheel by an angle θ with respect to the rotational axis of the workpiece, and sets the angle θ, workpiece circumferential speed v, grinding wheel circumferential speed V, and traverse speed that satisfy the following. Grinding is performed in step a.

<Operation> The rotational axis of the grinding wheel is tilted by an angle θ with respect to the rotational axis of the workpiece, and the workpiece and the grinding wheel are rotated in opposite directions.

A crack with an inclination of 30 degrees or less with respect to the rotation axis occurs in the workpiece.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIGS. 1 and 2, 10 is a workpiece, and 20 is a grinding wheel. The workpiece 10 is rotatably supported between a spindle side center 11 and a tailstock side center 12, and is rotationally driven by a workpiece drive motor of a circuit installed in the headstock 13 via a rotational drive member. . 14 is a tailstock that holds the center 12 on the tailstock side, and this tailstock 1
4 and the headstock 13 are installed on a circuit table, and the table is capable of traverse movement in a direction parallel to the rotation axis 0 of the workpiece 10.

The grinding wheel 20 is rotatably supported on a grinding wheel head 21 and is rotationally driven by a grinding wheel drive motor of a circuit. The rotational axis P of the grinding wheel 20 has two rotational axes 0. It is inclined by an angle θ with respect to the rotation axis O of the wire 10 around a line segment m connecting P at right angles. Note that the grindstone head 21 is used for the workpiece 10.
Plunge feeding is possible in the direction perpendicular to the rotational axis 0 of , that is, in the direction of line segment m.

Next, the operation will be explained based on the above-described configuration. The workpiece 10 and the grinding wheel 20 are rotated in opposite directions, that is, the workpiece 10 is rotated counterclockwise in FIG.
Rotate 0 clockwise.

Next, the grindstone head 21 is plunge-fed to move the workpiece 10 in a traverse manner, thereby performing cylindrical grinding of the workpiece 10.

When the circumferential speed of the workpiece is v, the circumferential speed of the grinding wheel is v, and the traverse speed of the workpiece 10 is a, the angle θ that satisfies the following conditions, the circumferential speed of the workpiece v, the circumferential speed of the grinding wheel v,
It is preferable to perform the grinding at a traverse speed a.

When grinding under the above conditions, cracks appear in the workpiece 10 in the direction of the arrow F as shown in FIG. 3, and the angle $ between the rotational axis O of the workpiece 10 and the arrow F becomes less than 30 degrees. The workpiece 10 ground under such conditions has no cracks in the direction perpendicular to the rotational axis 0 of the workpiece 10, so its bending strength does not deteriorate significantly.

In the present invention, cylindrical grinding may be performed in which the traverse speed a is zero and only plunge feeding is performed. When traversing the workpiece 10 or the grinding wheel 20, it is desirable to traverse in a direction that matches the direction of the velocity vector of Vsin θ.

<Effects of the Invention> As described above, the present invention performs grinding at an angle θ, a circumferential speed of the workpiece v, a circumferential speed of the grinding wheel V, and a traverse speed a that satisfy the conditional expression. A crack with an inclination of 30 degrees or less appears. As a result, there is an advantage that the bending strength of the workpiece does not decrease significantly due to grinding.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and Fig. 1 is a view from the rear of the grinding wheel, Fig. 2 is a cross-sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a view showing a cracked part Diagram showing the state. 10... Workpiece, 13... Headstock, 14... Tailstock, 20... Grinding wheel, 21... Grinding wheel head.

Claims (1)

[Claims] A cylindrical grinding method in which a workpiece and a grinding wheel are rotated in opposite directions to grind the workpiece into a cylindrical shape, the grinding wheel having two rotational axes that are aligned with the rotational axis of the workpiece. When the workpiece is tilted by an angle θ around a line segment connected at right angles, the circumferential speed of the workpiece is v, the circumferential speed of the grinding wheel is V, and the traverse speed of the workpiece relative to the grinding wheel in the direction of the rotational axis of the workpiece is a, (|Vcosθ−v| )/(|Vcosθ+a|)≦t
A cylindrical grinding method characterized in that grinding is performed at an angle θ that satisfies an30°, a circumferential speed of the workpiece v, a circumferential speed of the grinding wheel V, and a traverse speed a.