JP2583345B2 - Method for creating machining data of NC cam grinding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a method for creating machining data to be input to an NC cam grinding machine that automatically forms a cam, and particularly to a machining characteristic unique to the machine. The present invention relates to a machining data creation method for an NC cam grinding machine capable of creating machining data for forming a cam having an ideal cam curve as designed while taking into account.

(Prior Art) An NC cam grinding apparatus for automatically forming a cam is configured, for example, as shown in FIG.

As shown in the figure, a member to be ground 1 which is formed into a cam by grinding is rotated by a C-axis motor 2. A grindstone 4 rotated by a grindstone motor 3 in the same direction as the direction of rotation of the member to be ground 1 is attached to a slider (not shown). Direction, the grindstone 4 can be moved toward and away from the center axis. A nut (not shown) of a ball screw 6 driven by an X-axis motor 5 is attached to the slider, and the rotation of the ball screw 6 by the X-axis motor 5 causes the grindstone 4 to be attached to the workpiece 1. It comes into contact and performs grinding.

And these C-axis motor 2 and X-axis motor 5
Each is controlled by a controller (not shown).

This control device is constituted by a so-called computer or the like, and an internal memory stores cam curve data for grinding the workpiece 1 to a cam curve to be formed.

As shown in FIG. 11, the cam curve data is data represented by the rotation angle of the member to be ground 1 and the position of the grindstone 4 corresponding to the rotation angle.

Then, as shown in the drawing, the control device obtains processing data for moving the workpiece 1 and the grindstone 4 according to the cam curve data based on the cam curve data.

This processing data is data for controlling the C-axis motor 2 and the X-axis motor 5, and as shown in the drawing, is data indicating the rotational position of the member to be ground 1 and the moving position of the grindstone 4 according to the processing elapsed time. is there. Hereinafter, these data are referred to as C-axis position data and X-axis position data.

The control device feedback-controls the C-axis motor 2 and the X-axis motor 6 according to the position data in accordance with the processing elapsed time, and forms a cam having a cam curve according to the cam curve data for the workpiece 1 to be ground. Grinding is performed while the grindstone 4 is positioned at the same time.

As described above, the control device individually controls the X-axis motor 6 and the C-axis motor 2 based on the respective position data set in advance corresponding to the processing elapsed time, and the workpiece 1 and the grinding wheel 4 are controlled. By performing the above positioning control, the workpiece 1 is ground into a cam having a cam curve as designed.

Conventionally, production of cams by such a cam grinding apparatus is generally performed in the order of steps shown in FIG.

First, as described above, cam curve data is created based on the cam curve of the cam to be formed, and stored in the internal memory of the control device (first step).

Thus, when the processing is started, the control device obtains the processing data composed of the C-axis position data and the X-axis position data based on the cam curve data as described above (second processing).
Step), the member to be ground 1 is ground by controlling the respective motors based on the processing data to form a cam (third step).

The inspected inspector or the like inspects whether or not the processed cam has a cam curve as designed. Specifically, it is inspected whether the cam curve of the processed cam is within the allowable error with respect to the designed cam curve, that is, the ideal cam curve (fourth step).

As a result of the inspection, if the cam curve of the formed cam is within the allowable error, the processed cam is shipped as a product (fifth step).

On the other hand, if it is not within the allowable error, the cause of the processed cam not being within the allowable error is clarified, and the cam curve data is corrected so that the subsequently processed cam is within the allowable error, and again Then, grinding is performed according to the corrected cam curve data (sixth step).

As described above, conventionally, according to the processing data obtained based on the cam curve data corresponding to the ideal cam curve to be formed, the member to be ground 1 is ground and the processed cam curve is not within the allowable error. After elucidating the cause of such processing, the cam curve data is corrected so that the cam processed thereafter has an allowable error. As a result, the workpiece 1 to be processed thereafter becomes a cam having a cam curve within an allowable error of the ideal cam curve.

(Problems to be Solved by the Invention) By the way, as described above, the reasons why the cam curve after processing does not become the ideal cam curve as designed include, for example, (1) a so-called cumulative lead generated in a ball screw for moving a grindstone. (2) so-called backlash generated in the gear for driving the ball screw; (3) error in the rotational position of the member to be ground caused by an error in the gear for rotating the member to be ground; (5) Motor following delay caused by feedback control of each motor, (6) so-called centering error of the member to be ground, (7) reworking There is an outer diameter error of the grinding wheel caused by the reshaping.

Therefore, conventionally, if the cam curve after processing does not become an ideal cam curve due to these causes, the cam curve data is corrected and the processing is performed again. When it is difficult to find each cause from the subsequent cam curve, it is difficult to properly correct the cam curve data, and even if it is corrected, it is corrected by misregistration and it becomes defective even if it is processed again was there.

Also, as described above, if the member to be ground is sharply deviated from the ideal cam curve due to a plurality of causes, that is, if the grinding is excessive, even if the cam curve data is corrected, the grinding is performed once. The excessively ground member cannot be corrected within the allowable error of the ideal cam curve, and it has been difficult to reduce the incidence of such defective products.

Furthermore, since there are many causes of defective products as described above, we clarified the cause of processing failure,
There is also a problem that the operation until the correction of the cam curve data for the corresponding cause is extremely complicated.

The present invention has been made in order to solve such a conventional problem, and it is possible to create processing data for forming a cam having an ideal cam curve as designed while taking into consideration the processing characteristics unique to the apparatus. An object of the present invention is to provide a method for creating machining data of an NC cam grinding machine capable of performing the machining.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides processing data created on the basis of an ideal cam curve of a cam to be formed and input to an NC cam grinding apparatus for forming a cam. A method of forming the ideal cam curve, the theoretical target processing data, and the characteristic processing in which the mechanical characteristics and control characteristics of the NC cam grinding apparatus are added to the target processing data. After obtaining the data, the computer creates an expected cam curve and the ideal cam curve after machining based on the characteristic machining data and the target machining data, and compares the expected cam curve with the ideal cam curve. After calculating the error of the expected cam curve with respect to the ideal cam curve, the characteristic processing data is corrected so as to eliminate the error.

(Operation) The present invention configured as described above operates as follows.

First, based on the ideal cam curve of the cam to be formed, ideal target processing data and characteristic processing data in which the mechanical characteristics and control characteristics of the NC cam grinding device are added to the target processing data. Ask. Specifically, the target processing data is NC data represented by the rotational angle position of the member to be ground on which the cam is formed with respect to the processing elapsed time, and the moving position of the grindstone corresponding to the rotational angle position. or,
The characteristic machining data includes the mechanical characteristics of the NC cam grinding machine at these rotation angle positions and movement positions, that is, the accumulated lead errors, backlatts,
NC taking into account the control characteristics, that is, the tracking delay described above
Data.

Then, based on the characteristic processing data and the target processing data, a computer performs a so-called simulation to draw a predicted cam curve and an ideal cam curve after the processing.

As a result, the expected cam curve and the ideal cam curve can be compared, and the error of the expected cam curve with respect to the ideal cam curve becomes clear. Therefore, the characteristic processing data is corrected so as to eliminate this error.

The mechanical processing and control characteristics of the NC cam grinding apparatus are taken into account, and the characteristic processing data corrected so as to form a cam having an ideal cam curve is input to the NC cam grinding apparatus. Thereby, the NC cam grinding machine can form a cam having a cam curve within an allowable error with respect to the ideal cam curve.

As described above, since the characteristic processing data can be corrected so that a cam having an ideal cam curve is formed before the grinding is actually performed, the incidence of defective products can be reduced, and productivity can be reduced. It will be greatly improved.

In addition, even if the cam curve after processing does not fall within the allowable error of the ideal cam curve even though the grinding is performed according to the characteristic processing data corrected as described above, Other than the causes, for example, errors in centering the workpiece to be ground, and errors in the outer diameter of the grindstone caused by reshaping or reshaping, etc., may be used to correct the characteristic processing data again, that is, processing defects This makes it easier to find the cause of the misalignment, so that misregistration is not performed, and the work of correcting the data by elucidating the cause of the processing failure is facilitated.

(Example) Hereinafter, a method for creating machining data of the NC cam grinding machine according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an apparatus used for realizing a processing data creating method of an NC cam grinding apparatus according to the present invention, and FIGS. 2 to 7 are each a diagram shown in FIG. FIG. 3 is an explanatory diagram of data stored in a memory. FIG. 8 is a diagram showing an ideal cam curve and an expected cam curve displayed on the monitor shown in FIG. 1. FIG. 9 is a diagram showing processing data according to the present invention by the apparatus shown in FIG. FIG. 4 is a diagram illustrating a state in which a creation method is realized. In this embodiment, the NC cam grinding apparatus described in the related art is used, and a detailed description thereof will be omitted.

As shown in FIG. 1, in this embodiment, an NC cam grinding machine 10 similar to the conventional one is connected to a so-called computer 11.

The computer 11 has various memories 12, 13, 14, 15 for storing various data for obtaining data to be output to the NC cam grinding machine 10, and these memories 12, 13, 14, 15,
Data processing unit 16 that performs various processes on the data stored in the
And is constituted by.

The data processing unit 16 has respective memories 12, 13, 14, 15
Are connected to a data input device 17 for inputting data stored in the memory and correction values for correcting these data, and a monitor 18 for simultaneously displaying an ideal cam curve and an expected cam curve described later.

The data input device 17 is a so-called keyboard, and when cam curve data as shown in FIG. 11 obtained based on an ideal cam curve to be formed is input to the data input device 17 as in the related art. , The data processing unit 16
The cam curve data is stored in the cam curve data memory 12.

Further, the data processing section 16 obtains target processing data composed of X-axis position data and C-axis position data as shown in FIG. The data is stored in the memory 13.

Further, the characteristic data memory 14 stores various characteristic data corresponding to the mechanical characteristics and control characteristics of the NC cam grinding machine 10 shown in FIGS.

The NC cam grinding machine 10 has a so-called cumulative lead error (secondary error) generated in the ball screw 6 for moving the grinding wheel 4.
FIG.), The rotational position of the member 1 to be ground caused by the error of the gear for rotating the member 1 to be ground, that is, the error of the position of the C axis (FIG. 3), the so-called backlash generated in the gear for driving the ball screw 6 (FIG. 4), the amount of deflection of the member to be ground 1 caused by the contact of the grinding wheel 4 with the member to be ground 1 (FIG. 5), and the C-axis motor 2 and the X-axis motor 6 as shown in FIG. Since the follow-up delay of the motor caused by the feedback control occurs, the characteristic data memory 14 stores characteristic data corresponding to these characteristics. Specifically, corresponding to the order shown,
Cumulative read error data corresponding to the cumulative read error, C-axis position error data corresponding to the C-axis position error, backlash data corresponding to the backlash, deflection amount data corresponding to the deflection amount, and follow-up delay data corresponding to the follow-up delay. is there.

These characteristic data can also be input from the data input device 17, and the characteristic data corresponding to the characteristics of the NC cam grinding machine 10 to be used is stored in the characteristic data memory.
14 can be memorized.

Then, as shown in FIG. 7, the data processing unit 16 adds the characteristic data to the X-axis position data and the C-axis position data, which are the target processing data stored in the target processing data memory 13, X-axis processing data and C-axis processing data, which are processing data taking the above characteristics into account, are calculated, and these are stored in the characteristic processing data memory 15.

Further, the data processing section 16 causes the monitor 18 to display a predicted cam curve which is expected to be formed after processing according to the characteristic processing data thus obtained. Further, the data processing unit 16 includes a target processing data memory.
Similarly, the ideal cam curve is displayed on the monitor 18 at the same time in accordance with the X-axis position data and the C-axis position data stored in the memory 13.

Thus, each cam curve displayed on the monitor 18 is
As shown in FIG. 8, it is possible to confirm the error of the expected cam curve with respect to the ideal cam curve. In other words, the expected cam curve after processing and the ideal cam curve are so-called simulated and drawn by the computer 11, so that an error of the expected cam curve with respect to the ideal cam curve can be recognized.

Then, when a correction value for each of the characteristic processing data is input to the input device so that the error is eliminated, the data processing unit 16 converts each of the characteristic processing data to which this correction value has been added into the characteristic processing data again. It is stored in the memory 15. Further, the data processing section 16 outputs the characteristic processing data to the NC cam grinding apparatus 10, thereby causing the workpiece 1 to be actually ground and forming a cam substantially matching the ideal cam curve. ing.

By using the device configured in this way,
As shown in FIG. 9, the processing data creation method of the present invention can be realized.

First, cam curve data is created in advance based on an ideal cam curve of a cam to be formed, and this cam curve data is input to the input device 17 (tenth step).

Then, the data processing unit 16 stores the cam curve data in the cam curve data memory 12 and creates target machining data (X-axis position data and C-axis position data) based on the cam curve data. Is stored in the target machining data memory 13 (step in FIG. 11).

Next, the data processing unit 16 adds the various characteristic data stored in advance in the characteristic data memory 14 to the target processing data, thereby obtaining the mechanical characteristics and the control characteristics of the NC cam grinding machine 10. Is calculated, and the characteristic processing data (X-axis processing data and C-axis processing data) are calculated, and these are stored in the characteristic processing data memory 15 (twelfth step).

Then, the data processing unit 16 performs a processing simulation for displaying, on the monitor 18, an expected cam curve expected to be formed after the processing, according to the obtained respective characteristic processing data (a thirteenth step).

The data processing unit 16 also displays the ideal cam curve on the monitor 18 at the same time according to the target processing data (X-axis position data and C-axis position data) stored in the target processing data memory 13 (step 14). .

Thus, by visually checking the cam curves displayed on the monitor 18 in this way, it is possible to confirm the error of the expected calm curve with respect to the ideal cam curve (the fifteenth step).

Then, by inputting a correction value for each of the characteristic processing data to the input device 17 so that the error is eliminated, the data processing unit 16 adds the correction value to each of the characteristic processing data and converts each of the characteristic processing data. to correct. That is, the characteristic processing data is corrected so that the cam curve after processing becomes an ideal cam curve (16th step).

Further, the data processing unit 16 stores the corrected characteristic processing data in the characteristic processing data memory 15 again, and outputs the corrected characteristic processing data to the NC cam grinding apparatus 10. Thus, the NC cam grinding apparatus 10 actually performs the grinding process on the workpiece 1 in accordance with the corrected characteristic processing data, and forms a cam substantially matching the ideal cam curve (a seventeenth step).

When the grinding is completed, the inspector or the like inspects whether or not the ideal cam curve as designed is within an allowable error as in the conventional case (step 17).

As a result of this inspection, if the cam curve of the formed cam is within the allowable error, the processed cam is shipped as a product (step 19).

On the other hand, if not within the allowable error, return to the 16th step,
Causes that the processed cam curve does not fall within the allowable error, that is, causes other than the cause corresponding to various characteristic data added to the characteristic processing data first, such as an error in centering of the member to be ground 1, reshaping and shaping Paying attention to the outer diameter error or the like of the grindstone 4 caused by the correction, the characteristic processing data is corrected again so that the cam after processing is within the allowable error. At this time, if necessary, the characteristic data may be changed to newly calculate characteristic processing data.

As described above, the target machining data and the characteristic machining data are obtained by the computer 11 (tenth and twelfth steps), simulation is performed based on these data, and the predicted cam curve and the ideal cam curve after the machining are monitored. Since the error of the expected cam curve with respect to the ideal cam curve is clarified by displaying on the display 18 (the thirteenth step to the fifteenth step), the cam curve after the processing with respect to the ideal cam curve before the actual grinding is performed. Therefore, the characteristic processing data can be corrected so that this error is eliminated, that is, a cam having an ideal cam curve is formed (16th step). Then, the characteristic processing data corrected in this way is
By inputting to the NC cam grinding machine 10, a cam substantially matching the ideal cam curve is formed by the NC cam grinding machine 10 (17th step).

Therefore, since the characteristic processing data can be corrected so that a cam having an ideal cam curve is formed before the grinding is actually performed, the incidence of defective products can be reduced, and productivity can be greatly improved. Will do.

Even if the cam curve after processing does not fall within the allowable error of the ideal cam curve even though the grinding processing is performed according to the characteristic processing data corrected as described above, Causes that did not fall within the tolerance,
In other words, it is only necessary to pay attention to the cause other than the cause corresponding to the various characteristic data added to the characteristic processing data first, and correct the characteristic processing data again. Is eliminated, and the work of correcting the data by elucidating the cause of the processing failure is also facilitated.

Further, even when a cam is formed by using a plurality of such devices, the cam formed by each NC cam grinding device has a mechanical property unique to each NC cam grinding device. In addition, since variations in processing accuracy due to control characteristics are reduced, stable production is possible.

The specific data is not limited to the accumulated read error, the error of the C-axis position, the backlash, the amount of deflection, and the follow-up delay illustrated in the present embodiment, but also the mechanical characteristics and control related to the grinding of the NC cam grinding machine. It goes without saying that a cam closer to the ideal cam curve can be formed if finer characteristic data is set.

(Effects of the Invention) As is clear from the above description, the present invention has the following effects.

Since the characteristic processing data can be corrected so that a cam with an ideal cam curve is formed before grinding is actually performed, the incidence of defective products can be reduced, and productivity can be greatly improved. become.

Even if the cam curve after processing does not fall within the allowable error with respect to the ideal cam curve even though grinding is performed according to the characteristic processing data corrected as described above, It is sufficient to correct the characteristic processing data again by focusing on the cause other than the cause
Since the cause of the processing failure can be easily found, misregistration is not corrected, and the work of correcting the data by clarifying the cause of the processing failure is facilitated.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an apparatus used to realize a processing data creation method of an NC cam grinding apparatus according to the present invention;
2 to 7 are explanatory diagrams of data stored in the respective memories shown in FIG. 1, and FIG. 8 shows an ideal cam curve and an expected cam curve displayed on the monitor shown in FIG. Figure,
FIG. 9 is a view showing how the processing data creating method of the NC cam grinding apparatus according to the present invention is realized by the apparatus shown in FIG. 1, and FIGS. 10 to 12 are diagrams showing a conventional cam grinding processing. FIG. Reference numeral 1 represents a member to be ground, 4 represents a grindstone, 10 represents an NC cam grinding apparatus, 11 represents a computer, 12 represents a cam curve data memory, 13 represents a target processing data memory, 14 represents a characteristic data memory, and 15 represents a memory. …… Character processing data memory, 16 …… Data processing unit, 17 …… Data input device, 18 …… Monitor.

Claims (1)

(57) [Claims] 1. A method of creating machining data which is created based on an ideal cam curve of a cam to be formed and input to an NC cam grinding machine for forming a cam, wherein the cam having the ideal cam curve is formed. The theoretical target machining data
After obtaining mechanical processing characteristics and control characteristics of the NC cam grinding apparatus and characteristic processing data in consideration of the target processing data, a computer performs processing based on the characteristic processing data and the target processing data. After the expected cam curve and the ideal cam curve are created, and the expected cam curve is compared with the ideal cam curve to determine an error of the expected cam curve with respect to the ideal cam curve, the error is eliminated. A method for creating machining data for an NC cam grinding machine, wherein the characteristic machining data is corrected.