JPH0773824B2 - Method for correcting the grinding surface of the grinding wheel - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for correcting an outer peripheral grinding surface of a grindstone used for grinding.

(Prior Art) On the outer peripheral grinding surface of a disk-shaped grindstone (hereinafter referred to as a grinding wheel) used for grinding, the number of grinded works or the number of times of grinding a predetermined part of the work is a predetermined number. Each time, the corrections such as reshaping and reshaping are performed to restore the sharpness and shape of the grinding surface, but this correction is generally performed only when simply redressing the cylindrical grinding surface.
For example, a dresser made of single stone diamond, etc., is positioned laterally of the grinding wheel, toward the inner side in the radial direction of the wheel, which is the approaching direction of each other, and the tip of the dresser is located radially inward from the outer grinding surface of the wheel. , And then move the grindstone linearly in the axial direction so that the dresser cuts into the outer peripheral grinding surface of the grindstone, and the outer peripheral grinding surface has a predetermined cross-sectional shape. If you also want to fix it,
For example, a forming dresser having a cross-sectional shape corresponding to the shape to be corrected is fed inward in the radial direction of the grindstone at a position facing the outer peripheral grinding surface of the grindstone so that the dresser is attached to the outer peripheral grind surface of the grindstone. Make a cut.

Therefore, at the time of the above correction, the feed amount of the dresser to be fed inward in the radial direction of the grindstone is at least a radius decrease amount of the grindstone worn by the grinding process between the correction time and the next correction time,
It is necessary to add a proper cutting amount of the dresser in the radial direction of the grindstone capable of recovering a predetermined sharpness or shape to the outer peripheral grinding surface.

By the way, when the outer peripheral grinding surface of the grinding wheel is used, the reduction amount due to wear of the radial dimension of the grinding wheel with respect to the number of workpieces tends to increase as the diameter of the grinding wheel generally decreases even if the grinding surface is not corrected. On the other hand, when the dresser is fed inward in the radial direction of the grindstone when the grinding surface is corrected, conventionally, a method has been conventionally used in which the dresser is further fed by a fixed amount from the position of the dresser at the time of the previous correction.

However, this makes it possible to correct the grinding surface from the beginning of use of the grinding wheel with a feed amount that is a large reduction amount due to wear when the radius of the grinding wheel is close to the minimum usable diameter and the appropriate depth of cut described above. It is necessary to perform it, and unless the radius of the grindstone is close to the minimum diameter, the cutting amount of the dresser into the grindstone is always unnecessarily increased.

Therefore, the applicant previously proposed in Japanese Patent Application No. 62-181245 a correction method for increasing the feed amount of the dresser from the previous correction position in accordance with the decrease in the radial dimension of the grinding wheel. That is, according to this method, the amount of decrease due to wear of the grindstone is small at the beginning of use, the feed increase amount from the position of the dresser at the time of the previous correction is reduced, and the feed increase amount is increased according to the increase in the decrease amount due to wear of the grindstone Since it can be increased, the cutting amount of the dresser to the grindstone can be maintained at an appropriate cutting amount, and unnecessary wear of the grinding grindstone and the dresser can be prevented.

(Problems to be Solved by the Invention) By the way, the inventors of the present application have found the following improvements while further researching the above method.

That is, in the above method, it is assumed that the radius of the grindstone decreases as the total number of workpieces processed increases,
As shown in the figure, the grinding wheel is corrected every time a certain number of workpieces are machined, and the amount of feed from the dresser position at the time of the previous correction is increased at the time of this correction, so the wheel wear progresses normally. In this case, as shown in the upper left portion of FIG. 5, the feed increase amount c is appropriately increased corresponding to the radius decrease amount a due to wear between the correction (shown by R in the figure) and the correction. Although the cutting amount b of the dresser can be set to an appropriate amount, the hardness of the work is particularly high in the process of grinding a particular work, or the chips during grinding are seized on the surface of the work by quenching. If abnormal wear occurs in the grinding wheel at the point A in the figure, the feed amount of the dresser is increased assuming the decrease of the magnet radius as shown by the broken line in the figure, so a proper amount of cutting is performed. Within the range shown by B in the figure up to the time of correction Cut dresser is not performed as shown in, or lack of the depth of cut, low result surface finish precision work was likely to be produced.

The present invention provides a correction method that advantageously eliminates the above-mentioned improvements.

(Means for Solving the Problem) A grinding surface correcting method for a grinding wheel of the present invention is a dresser or a grinding wheel, which corrects an outer peripheral grinding surface of the grinding wheel by feeding them in a mutually approaching direction, When increasing the feed amount from the previously corrected position in accordance with the decrease in the radial dimension of the grinding wheel, the position of the processing surface of the workpiece ground by the grinding wheel and the feed state in which the grinding processing was performed Obtaining the actual radius of the grinding wheel based on the center position of the grinding wheel, changing the feed amount based on the actual reduction amount of the grinding wheel obtained from the change of the actual radius before and after the grinding process of the workpiece. Is characterized by.

(Operation) In such a method, the position of the work surface of the work is obtained as the dimension of the work is measured after the work is ground, and the grinding wheel in the feed state where the work is ground is also performed. The center position of the grinding wheel is calculated, and the actual radius of the grinding wheel (actual radius) is calculated from those positions.
Before and after grinding the work, that is, from the change immediately after correction and after grinding a predetermined number of works, calculate the actual reduction amount of the grinding wheel (actual reduction amount), and correspond to that actual reduction amount, Change the feed increment of.

Therefore, according to this method, even if the actual reduction amount of the grinding wheel at the time of the predetermined correction is significantly increased due to the occurrence of abnormal wear, the depth of cut of the dresser can be always set to an appropriate amount, so that the surface finishing accuracy is low. There is little or no possibility of workpieces being produced.

Embodiment An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a configuration diagram showing a cylindrical grinder to which an embodiment of a method for correcting a grinding wheel of the present invention is applied, in which 1 is a main body,
2 indicates a grinding wheel, and 3 indicates a work.

The grinding wheel 2 here has a disk shape and is pivotally supported by the wheel head 4 and its center extending in a direction orthogonal to the plane of the drawing based on the operation of a wheel driving motor (not shown) on the wheel head 4. Rotate around axis A.

Further, the work 3 here has one end held by a chuck 5 attached to a main shaft (not shown) provided on the main body 1 and the other end supported by a tailstock (not shown) to drive the main shaft. The rotation of the spindle drive motor causes the workpiece 3 to rotate about the central axis B of the workpiece 3 aligned with the central axis of the spindle extending parallel to the central axis A.

The grindstone base 4 that supports the grinding wheel 2 includes a drive mechanism that moves a ball nut that is screwed therein by the rotation of a ball screw shaft, and a guide mechanism that guides the movement of a slider fitted therein by a linear guide. It is supported by a right-angled feed table 7 through a parallel feed mechanism 6 which has a right-angled feed mechanism 8 which is a mechanism similar to the parallel feed mechanism 6.
It is supported by the main body 1 via.

Here, the parallel feed mechanism 6 operates the parallel feed motor 9 that drives the ball screw shaft to move the grinding stone head 4, and thus the grinding wheel 2 in the extending direction of the axis A, that is, the extending direction of the axis B of the work 3. Move back and forth to. Right angle feed mechanism 8
On the basis of the operation of the right-angle feed motor 10 for driving the ball screw shaft, to the right-angle feed base 7, and then to the grinding wheel 2, from the direction perpendicular to the axis B of the work 3 to the work 3, as indicated by the arrow C in the figure. Providing an approaching right-angle feed movement and an opposite right-angle return movement.

The right-angled feed base 7 also supports a dresser 12 having a single stone diamond at its tip through a dresser feed mechanism 11 that is the same mechanism as the parallel feed mechanism 6, and the dresser feed mechanism 11 uses a ball screw shaft. Driven dresser feed motor 13
Based on the above operation, the dresser 12 is caused to move toward the grinding stone 2 from a direction perpendicular to the axis A of the grinding stone 2 as shown by an arrow D in the figure, and to return to the opposite direction.

Reference numeral 14 in the figure denotes a control device for numerical control (NC) of the operation of each of the motors. The control device 14 includes an input unit 15, a storage unit 16,
It has a calculation / control unit 17 and a machining number counter 18.

Here, the input unit 15 receives a direct operation signal and a control program signal from the operation panel 19 and a dimension measuring device 20 for measuring the outer diameter dimension of the workpiece 3 during grinding by the contact of the probe 20a with the workpiece 3. The dimension signal is input and sent to the calculation / control unit 17, and the calculation / control unit 17 sends the input control program to the storage unit 16 for storage by a normal CPU and stores the control program or the control program read therefrom. Based on the direct operation signal, a signal is output to the drive circuits 21 to 25 of each of the motors to control the operation of those motors, and the machining number counter 18 counts the number of workpieces 3 for which predetermined grinding is completed. And sends the processed number to the calculation / control unit 17.

In this embodiment, the control program shown in FIG. 2 is executed by this cylindrical grinding machine having such a configuration to grind a large number of workpieces 3.

That is, here, first, in step 101, the work 3 is ground. This grinding process includes instructions of the rotation speed of the work 3 included in the control program, the rotation speed of the grinding wheel 2, the feed amount and the feed speed of the parallel and right-angle feed movement of the grinding wheel 2, and the dimension from the dimension measuring device 20. On the basis of signal feedback or the like, the outer peripheral surface 3a of the grinding wheel 2 is provided so that the outer peripheral surface 3a of the work 3 has a predetermined outer diameter and a predetermined finishing accuracy.
Using.

In the next step 102, the number of workpiece machining counted by the machining number counter 18 is checked, and if the number of machining has not reached a predetermined number required to correct the outer peripheral grinding surface 2a, the following step 103
Then, the presence or absence of the work 3 to be processed next is checked, and then the process returns to step 101.

In step 102, if the number of machining operations has reached a predetermined number that requires correction of the outer peripheral grinding surface 2a, step 104
And proceed to the dresser based on the positional relationship shown in FIG.
Calculate the feed amount f _D from the 12 origins.

That is, here, the radius r after grinding of the workpiece 3 and
The position F of the machining surface of the work 3 is obtained from the position E of the center axis B of the work 3 which is fixed to align with the center axis of the main shaft, and the origin position G of the center axis A of the grinding wheel 2 is obtained.
And the right-angle feed amount f _g for grinding the work 3,
The position H of the central axis A of the grindstone 2 in the feed state where the grinding process is performed as shown by the imaginary line in the figure is obtained, and first, from the distance between the position F and the position H, when the grinding process is completed Find the actual radius R ₁ of the whetstone 2. In addition, specifically, the following equation is calculated using the distance L _w between the position E and the position G.

R ₁ = L _w −r−f _g (1) Next, here, the proper cutting amount b of the dresser 12 that can restore a predetermined sharpness or shape to the outer peripheral grinding surface 2 a of the grinding wheel 2 is the actual radius R ₁ Assuming the corrected radius R ₂ subtracted from
Of the grinding wheel 2 of the corrected radius R _2, from the position I of the outer circumferential grinding surface 2a of the case where the center axis A is positioned at the home position G, the origin position J of the tip of the dresser 12, the feed amount of the dresser f _D Ask for. In addition, specifically, the following equation is calculated using the distance L _D between the position G and the position J.

By performing _{R 2 = R 1 -b ... (} 2) f D = L D -R 2 ... (3) such operation, based on the actual decrease amount of the actual radius R ₁ of the grinding wheel 2, the proper depth of cut b It is possible to obtain the dresser feed amount f _D that can secure the above.

After that, in step 105, the central axis A is the origin position G.
The dresser 12 is moved by the feed amount f _D from the limited position J at the tip of the dressing wheel 2 located at
Alternatively, the outer peripheral ground surface 2a is corrected so as to have an appropriate depth of cut b by moving the peripheral grinding surface 2a from a position close to the outer peripheral grinding surface 2a to the position I, and feeding the grinding wheel 2 in parallel therewith.

Then, by returning to step 103, the above steps are repeated here until the next work 3 is exhausted, that is, the machining of the predetermined number of works 3 is completed.

Therefore, according to this method, every time a predetermined number of workpieces 3 are processed, the feed amount from the position at the time of the previous correction of the tip of the dresser 12 is increased according to the decrease in the radius of the grinding wheel 2, and Since the feed increase amount is changed in accordance with the actual reduction amount of the radius of the grinding wheel 2, the grinding wheel 2 is abnormally worn during the predetermined number of machining, for example, at the time point A in FIG. Even when the amount is significantly increased as indicated by h in the figure, the feed amount of the dresser 12 at the time of the subsequent correction can be increased as indicated by i in the figure and the depth of cut can be set to the proper depth of cut b. As a result, there is little or no possibility that a work with low surface finish accuracy will be produced.

Although the present invention has been described above based on the illustrated example, the present invention is not limited to the above-described example, and for example, a dresser may be fixed and a grinding wheel may be sent toward the dresser. In addition, this method is
By actually measuring the position of the processed surface of the work, it can be easily applied to a surface grinder.

(Effect of the invention) Thus, according to the grinding surface correction method of the effect of the present invention, even when the actual reduction amount of the grinding wheel during the predetermined correction greatly increases due to the occurrence of abnormal wear, the depth of cut of the dresser is always an appropriate amount. As a result, it is possible to eliminate the possibility that a work with low surface finish accuracy will be produced with little or no effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing a cylindrical grinder to which an embodiment of a method for correcting a grinding surface of a grinding wheel of the present invention is applied, and FIG. 2 shows a control program for causing the cylindrical grinder to execute the method of the embodiment. FIG. 3 is a flow chart, FIG. 3 is a schematic diagram showing a positional relationship between a grinding wheel, a work and a dresser in the cylindrical grinder, FIG. 4 is a flow chart showing a conventional method, and FIG. It is a relationship diagram which shows the relationship of. DESCRIPTION OF SYMBOLS 1 ... Main body, 2 ... Grinding wheel 2a ... Outer peripheral grinding surface, 3 ... Work piece 9 ... Parallel feed motor, 10 ... Right angle feed motor 12 ... Dresser, 13 ... Dresser feed motor 14 ... NC control device, 20 ... Dimension measuring device

Claims (1)

[Claims] 1. An outer peripheral grinding surface of a grinding wheel is corrected by feeding a dresser or a grinding wheel in a direction in which they approach each other, and a feed amount of the dresser from a previously corrected position is a radial dimension of the grinding wheel. When increasing according to the decrease, the actual radius of the grinding wheel based on the position of the processing surface of the workpiece ground by the grinding wheel and the center position of the grinding wheel in the feed state where the grinding processing was performed. A method for correcting a grinding surface of a grinding wheel, wherein the feed amount is changed based on an actual reduction amount of the grinding wheel obtained from a change in the actual radius before and after a work is ground.