WO2001023140A1

WO2001023140A1 - Grinding method using cnc grinding machine

Info

Publication number: WO2001023140A1
Application number: PCT/JP2000/006452
Authority: WO
Inventors: Masaru Yamamoto; Yoshifumi Nakano
Original assignee: Shigiya Machinery Works Ltd.
Priority date: 1999-09-27
Filing date: 2000-09-20
Publication date: 2001-04-05
Also published as: JP3479717B2; JP2001088026A

Abstract

A grinding method using a CNC (computer numerical control) grinding machine employed for the grinding of cams on cam shafts, crank pins for crank shafts, etc. Work (w) is rotated around a particular centerline (9) by a work support rotating means (6, 7), during which rotation, when the portion (a) of the work is to be ground while moving a grinding stone (10) radially of the rotating work so as to correspond to the finish shape and size of the work, the work is ground to an approximate finish dimension, whereupon the ground portion corresponding to each rotation phase angle within the range of one revolution of the work is measured by a measuring means, the value by which each rotation angle position is to be corrected is calculated from the result of the measurement, and the finish-grinding of the ground portion of the work is effected on the basis of the corrected value. Even if the work is such that its grinding resistance, rigidity or the like varies for each rotation phase angle, it can be accurately ground to a predetermined finish shape and dimension as errors caused grinding during the grinding are corrected for each rotation phase angle.

Description

Specification

Grinding method with CNC grinder

The present invention relates to a grinding method using a CNC (computer numerical control) grinder, which is performed by grinding a cam of a camshaft or a crankpin of a crankshaft. Background art

When grinding a crankpin with a CNC grinder, the workshaft is used to rotate the crankshaft as a work around the center line of the journal by means of the work supporting and rotating means, and the grinding wheel follows the crankpin during this rotation. In some cases, the circumferential surface of the crankpin is ground while moving in the direction of the turning radius.

Generally, in this grinding, the entire peripheral surface of the crankpin tends to be formed in a non-circular shape due to a change in grinding resistance and rigidity for each rotation phase angle of the crankshaft as a work.

Such a situation is not limited to crankshaft grinding.For example, the same applies to the case where a camshaft as a workpiece is rotated around a cam rotation center by a CNC grinding machine and the cam is ground. However, the cam is not ground according to the finish grinding data due to changes in the grinding resistance and rigidity for each rotation phase angle of the camshaft. Disclosure of the invention

Under such circumstances, the present invention corrects errors caused by this in the course of grinding, even in the case of a workpiece in which the grinding resistance, rigidity, etc., changes at each rotation phase angle in grinding with a CNC grinding machine. The purpose is to be able to accurately grind to the expected finished shape and dimensions.

The present application relates to a grinding method using a CNC grinder, and in the first invention, As described in claim 1, the work is rotated around a specific center line by the work supporting and rotating means, and during this rotation, the grinding wheel is moved in the radial direction of the work rotation so as to correspond to the finished shape and dimensions of the work. When grinding the workpiece while moving it, after grinding to the vicinity of the finished dimension of the workpiece, the measuring part corresponding to each rotation phase angle within one rotation range of the workpiece is measured by the measuring means. The correction value for each angular position is calculated, and the finish grinding of the work is performed based on this correction value.

According to this, the influence of changes in the grinding resistance, rigidity, etc., at each rotational phase angle of the workpiece is calculated as a correction value, and the finish grinding based on this correction value eliminates the effect. It will be.

In the second invention, as described in claim 2, the crankshaft as the work is rotated around the journal center line by the work supporting rotating means, and the grinding wheel follows the crankpin during the rotation. When grinding the crankpin while moving the workpiece in the radial direction of the work, after grinding to near the finishing dimension of the crankpin, the grinding portion of the crankpin corresponding to each rotation phase angle within one rotation range of the work is ground. The roundness is measured by a measuring means, a correction value for each rotation phase angle is calculated from the measurement result, and the finish grinding of the crankpin is performed based on the correction value.

According to this, despite the fact that the crank pin revolves around the journal center line, the effects of changes in grinding resistance, rigidity, etc. at each rotational phase angle of the work are eliminated. .

According to the third invention, as described in claim 3, the crankshaft as the work is rotated around the journal center line by the work supporting rotation means, and the grinding wheel follows the crankpin during the rotation. When grinding the crankpin while moving it in the radial direction of the work 15 times, after grinding to near the finish dimension of the crankpin, grinding of the crankpin corresponding to each rotation phase angle within one rotation range of the work The roundness of the part is measured by measuring means, and based on the measurement result, it is determined whether or not the cross-sectional shape of the crankpin is an ellipse. If the shape is an ellipse, the phase angle of the ellipse around the center of the crankpin is determined 90 degrees Elliptical data representing the rotated state is calculated, and the finish grinding of the crankpin is performed based on the elliptical data.

According to this; data for finish grinding in consideration of the grinding error up to the point of measurement of the crankpin is mechanically specified by the elliptical data specified by the measurement of the crankpin.

In the fourth invention, as described in claim 4, the work is rotated around a specific center line by the work supporting / rotating means, and during this rotation, the grinding wheel is adjusted so as to correspond to the finished shape and dimensions of the work. When grinding the workpiece while moving it in the direction of the radius of rotation, after grinding to the vicinity of the finished dimension of the work, measure the grinding points corresponding to each rotation phase angle within one rotation range of the work by measuring means. A finoleta process is performed to remove the surface roughness component of the ground surface from the result, and a correction value for each of the rotation phase angles is calculated from the processing result. Based on the correction value, finish grinding of the workpiece is performed. Implement as if it were done.

According to this, the filter processing makes the correction value accurate and improves the precision of the finish grinding.

In the fifth invention, as described in claim 5, the work is rotated around the specific center line by the work supporting and rotating means, and during this rotation, the grinding wheel is adjusted to correspond to the finished shape and dimensions of the work. When grinding a workpiece while moving it in the direction of the radius of rotation, a spark work is performed after the work is finished to the vicinity of the finish dimension of the work, and after the work has completed at least one revolution during the spark out, or the end of the spark work. Later, the grinding part corresponding to each rotation phase angle within one rotation range of the work is measured by the measuring means, and a correction value for each rotation phase angle is calculated from the measurement result. Perform so that finish grinding is performed.

According to this, when measuring the dimensions of the grinding portion, since the work is subjected to spark-coating processing all around the grinding portion, no step is formed on the grinding surface due to the cutting of the grinding wheel. Accurate measurement is performed, and the accuracy of finish grinding is improved. Brief description of the drawing

FIG. 1 is a plan view showing a CNC grinder used in the present invention.

FIG. 2 is a front view showing a state in which the crankshaft is supported by the support rotating means of the grinding machine.

FIG. 3 is a graph showing the relationship between the grinding wheel position of the grinding machine and the grinding time. FIG. 4 is a side view showing the state of a rotary grindstone and a workpiece when the crankpin is ground by the grinding method using the grinding machine.

FIG. 5 is a diagram showing a flow of a grinding process when a process for correcting a work error is performed by an in-process.

FIG. 6 is a side view in which the position of the crankpin of the crankshaft is cut and shown.

FIG. 7 is a diagram showing a flow of a grinding process in a case where a process for correcting an error of a work is performed by a bost process. BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the grinding method according to the present invention will be described with reference to FIGS.

Fig. 1 shows a well-known general CNC grinder used to grind cylindrical bodies and forces. 1 is a bed, and 2 is a bed 1 that can be freely moved in the horizontal direction (Z direction). The work support table 3 is a grindstone table provided on the bed 1 so as to be movable in the front-rear direction (X direction).

Numeral 4 is a servo motor for feeding the work support table 2 provided at the same part as the bed 1, and is configured to feed and move the work support table 2 in the Z direction via a screw feed mechanism (not shown). .

Reference numeral 5 denotes a servomotor for feeding the grinding wheel head 3 provided at the same part as the bed 1, and is configured to feed and move the grinding wheel head 3 in the X direction via a screw feed mechanism (not shown).

On the work supporting table 2, a work supporting and rotating means having a headstock 6 and a tailstock 7 is formed. 8 is a servo motor for driving the spindle 9 provided on the headstock 6; 10 is a rotating grindstone fixed to the grinding wheel rotating shaft 11 of the grinding wheel head 3; 1 2 Is a motor for rotating the grinding wheel rotating shaft 11. At this time, as shown in FIG. 2, the headstock 6 is provided with a chuck 13 which is rotatably driven in the same manner as the spindle 9, and the tailstock 7 is provided with a center 14 which is arranged concentrically with the spindle 9. Provide. In this case, a headstock may be provided instead of the tailstock 7, and a chuck similar to the chuck 13 that is arranged concentrically with the spindle 9 and performs synchronous rotation may be provided. A known sizing device 15 for measuring the diameter of the crankpin a during grinding is provided on the grindstone table 3. The sizing device 15 has a hook-shaped contact 15a that is in contact with the peripheral surface of the crankpin a, and the contact 15a is always kept in contact with the peripheral surface of the crankpin a. Swinging arm type supporting means 15b.

In the numerical control device (not shown) of the CNC grinding machine described above, a program for executing the following automatic processing is stored.

Then, a crankshaft w is placed between the chuck 13 of the headstock 6 and the center 14 of the tailstock 7, and each end of the crankshaft w is connected to these chucks 13, Hold it at 14. At this time, the center of the journal b of the crankshaft w is matched with the rotation center of the main shaft 9.

After that, perform necessary operations to start automatic grinding.

The contents will be sequentially described below. First, before entering step s100 in FIG. 5, the motor 12 is rotated, and the grinding wheel 10 is rotationally driven. Further, the servo motor 4 is rotated as necessary, and the work support table 2 is moved in the Z direction. As a result, the work w is moved together with the headstock 6 and the like, and the crank pin a to be ground faces the grinding wheel 10 in the X direction. Subsequently, the grinding wheel head 3 is positioned on the machine coordinates at a coordinate position p1 specified in advance by the program as shown in FIG.

Next, the servomotor 5 is rotated at a relatively high speed to feed the grinding wheel head 3, whereby the wheel head 3 rapidly advances, and the grinding wheel head 3 is moved to the coordinate position P 2 specified in advance in the machine coordinates by the program. Moved to

Thereafter, the servo motor 5 and the servo motor 8 are controlled and rotated at a related speed by a previously input program, whereby the grinding wheel 10 is rotated. As shown in FIG. 4, the reciprocating displacement in the X direction follows the rotation of the work w with the diameter of the rotation locus m of the crank arm c as the stroke. During this displacement, the work shown by step s100 in FIG. The rough cutting of w (crank pin a) is started, and the crank pin a being processed is to be ground by the opto-type. This rough grinding cut is continued until the grinding wheel head 3 reaches the coordinate position p 3 previously specified by the program on the machine coordinates. Then, during the time when the wheel head 3 reaches the coordinate position p 3 on the machine coordinates until it reaches another coordinate position p 4, the middle rough cutting is performed in step s 101.

After the wheelhead 3 reaches the coordinate position p4, spark-out is performed in step s102 in FIG. 5, that is, the cutting feed is stopped while the grinding wheel 10 is rotating. Then, the grinding wheel 10 is pressed by the crank pin a being processed by the elastic force or the like remaining on the machine components, and this pressing is continued during a period in which the workpiece w is rotated a plurality of predetermined times. You.

If this spark wrap is performed for at least one rotation of the work w, the entire peripheral surface of the crank pin a being processed is a smooth curved surface with almost no step due to the cut.

After the spark discharge, the process proceeds to step s103 in FIG. 5 so that the sizing device 15 measures the roundness of the crankpin a as a grinding portion. At this time, the diameter of the crank pin a to be ground has been ground to a dimension t 0 slightly larger than the finished dimension.

By the way, in the grinding up to the spark-out of step s102, the crank pin a becomes a perfect circle when it is assumed that the grinding resistance and rigidity for each rotation phase angle of the crankshaft w are constant. Grinding is performed according to the appropriate grinding data.

Since the crankshaft w actually changes periodically in response to the rotational phase angle, the cross-sectional shape of the crankpin a after the spark-out in step s102 is Under the conditions considered, what should be a perfect circle will not be a perfect circle, but will generally be an ellipse as shown by the imaginary line k in FIG.

Therefore, it is necessary to perform a process for correcting the ellipse to a perfect circle. This may be done in-process or in a post-process. '

First, the case of performing in-process will be described with reference to FIG. 5 as follows.

That is, after the work w has made at least one rotation during the spark-out in step s102, the roundness of the crank pin a for each rotation phase angle of the work w is determined by the sizing device 15. Measure and create measurement data. Then, in step s103, a filter process for removing a surface roughness component from the measurement data is performed, and a non-circular component is extracted. Next, the process proceeds to step s104, where a correction value for each rotation phase angle is calculated, and this correction force and finish grinding data are created. At this time, it is advantageous to obtain the high accuracy by performing the measurement of the crankpin a during the processing for one rotation immediately before the start of the fine polishing in step s105, which is advantageous for obtaining high accuracy. In this method, only high-frequency components larger than a specific frequency related to surface roughness are removed. Then, based on this finish grinding data, refinement of step s105 by numerical control is performed, and the crankpin a processed in this way has almost finished dimensions t1 and its cross section The shape becomes an exact perfect circle.

After the end of step s105, the process proceeds to step s106, and a snow cut is executed. In this spark-out, the grinding wheel 10 cuts and feeds based on the finished grinding data. The workpiece w is rotated by a preset number of revolutions under the condition that the workpiece w is brought into contact with the crank pin a while being controlled so as not to exist. As a result, the finished crank pin a has the finished dimension t 10 and has a smooth and continuous ground surface. Thereafter, the grinding wheel head 3 is separated from the workpiece w.

In this finishing process, the process from step s102 to steps s105, s104, s105, and s106 is performed for each crank pin a to be ground. Because

Next, the case in which the process is performed by the boost process will be described with reference to FIG. 7 and the like. That is, after performing the same processing from step s100 in FIG. 5 to step s101, the process proceeds to step s102, and the workpiece is moved a plurality of times scheduled in advance. Rotate to complete spark-out and finish the grinding process once.

Next, the process proceeds to step s110. In step s110, the ground crank pin a is measured using the sizing device 15 or other suitable measuring device. Measure the roundness of the grinding part for each rotation phase angle and create measurement data. Then, in step s111, a non-circular component is extracted in the same manner as in step s103. Next, the process proceeds to step s112, where finish grinding data is created in the same manner as in step s104, and finish grinding by numerical control is executed based on the finish grinding data. After the finish grinding, as in the case of the in-process, the process proceeds to step s1 13 and then a similar spark out is performed in step s1 14. Get away from.

When performing the finishing process by this post process, the series of processes shown in Fig. 7 above is executed only in the grinding of the first crank pin a. After the medium and rough grinding in step s 1 O 1, the final grinding data obtained in the first grinding process without going through steps sl 0 2, sll O, si 11, and si 12 The fine grinding in step s113 is performed based on the above, and thereafter, the process proceeds to step s114 to perform a final spark coat and finish the grinding of one crank pin a. Thereafter, the same processing and operation as the first processing are performed.

When the appropriate number of crankpins a are ground by the boston process in this manner, the same finish grinding cannot be obtained with the first finish grinding data because the sharpness of the grinding wheel 10 changes. There is a fear. For this reason, after grinding the appropriate number of crankpins a after the second, the grinding corresponding to the first is performed again, and thereafter, the same processing as described above is repeated.

In the above-described grinding of the crankpin a, the transition from one crankpin a to another crankpin a can be performed automatically or manually. Is also good.

The grinding shown in FIG. 7 described above can be modified as follows. That is, the same process is executed from step s100 to step s102, and in step s110, the crankpin _a which has reached this stage is measured in the same manner as described above. It is determined whether or not the cross-sectional shape of the pin a is an ellipse as shown by the imaginary line k in FIG. 6, and if this is an ellipse, the phase angle of the ellipse around the center of the crankpin a is rotated by 90 degrees in mechanical coordinates. In this state, elliptical data representing the shape indicated by the dotted line k1 in the figure is calculated, and based on the elliptical data, finish grinding data for the crankpin a is created. Perform as if you were to do so. The finish grinding data can be ground to a similar ellipse smaller by a certain dimension than the ellipse of the shape indicated by the dotted line k1 in FIG.

According to this finish grinding, the excess and deficiency with respect to the perfect circle n shown by the solid line are offset as judged from Fig. 6, and as a result, the crank pin a is not practically hindered, It is ground to a perfect circle.

On the other hand, if the cross-sectional shape of the crankpin a is not elliptical in the above determination, the processing by the post process shown in FIG. 7 described above is performed in step s111, step s112, step s113, Steps s 1 1 4 are performed in this order.

In the above embodiment, the case where the finish grinding data is corrected before the fine polishing is described. However, the same processing as before may be performed after the fine polishing. The work w is a crank pin and has been described in the case of grinding it by an open method.However, the invention is not limited to this.For example, the work w is a cam shaft and the cam is cammed. Grinding while rotating around the center of rotation can be carried out in accordance with the above, and the peripheral surface has an arbitrary cross-sectional shape or an arbitrary polygon such as a triangle. The same can be applied to the case where grinding is performed while rotating this around a specific rotation center line. .

According to the above-described present invention, the following effects can be obtained.

That is, according to the first invention, in the grinding by the CNC grinder, Even for workpieces that vary in grinding resistance, rigidity, etc. for each phase angle, errors during each rotation phase angle due to this can be corrected during the grinding process, and the workpiece can be accurately ground to the expected finished shape. It is.

According to the second aspect, despite the fact that the crank pin is ground by the open method, the influence of changes in the grinding resistance, rigidity, etc. at each rotational phase angle of the work is eliminated, and the work is accurately ground to a perfect circle. After fixing one crankshaft to the supporting and rotating means, it is possible to grind any crankpin without releasing this fixation, greatly improving the efficiency of grinding work. That's it.

According to the third invention, the finish grinding data, which is obtained by correcting the grinding error up to the time when the crankpin is measured, is mechanically specified by the elliptical data specified by the crankpin measurement, and The work can be ground to an exact circle without calculating the correction value for each phase angle.

According to the fourth aspect, the correction value becomes accurate by the filter processing, and the precision of the finish grinding can be improved.

According to the fifth invention, at the time of measuring the dimensions of the grinding portion, the entire periphery of the grinding portion is processed by the spark coat, so that the accurate measurement of the workpiece grinding portion is performed and the accuracy of the finish grinding is improved. It can be further improved.

Claims

The scope of the claims

1. The work (w) is rotated around the specific center line (9) by the work supporting rotation means (6, 7), and during this rotation, the grinding wheel (10) is adjusted to correspond to the finished shape and dimensions of the work. When grinding the workpiece while moving it in the radial direction of the workpiece, the grinding point (a) corresponding to each rotation phase angle within one rotation range of the workpiece is measured by the measuring means after grinding to the vicinity of the finished dimension of the workpiece. A grinding method using a CNC grinding machine, comprising: calculating a correction value for each rotation phase angle from the measurement result; and performing finish grinding of the workpiece based on the correction value.

2. The crank shaft (w) as a work is rotated around the journal center line (b) by the work supporting rotating means (6, 7), and during this rotation, the grinding wheel (10) is moved to the crank pin. When grinding the crankpin while moving it in the radius direction of the workpiece so as to follow (a), after grinding to the vicinity of the finish dimension of the crankpin, the crankpin was adjusted to each rotation phase angle within one rotation range of the workpiece. The roundness of the grinding portion of the crankpin is measured by measuring means, and a correction value for each rotation phase angle is calculated from the measurement result, and the finish grinding of the crankpin is performed based on the correction value. Grinding method using a CNC grinder.

3. The crankshaft (w) as a work is rotated around the journal center line (b) by the work supporting rotating means (6, 7), and during this rotation, the grinding wheel (10) is moved to the crankpin. When grinding the crankpin while moving it in the direction of the workpiece rotation radius so as to follow (a), after grinding to the vicinity of the finish dimensions of the crankpin, each rotation phase angle within one rotation range of the workpiece The measured roundness of the ground portion of the crankpin is measured by measuring means, and based on the measurement result, it is determined whether or not the cross-sectional shape of the crankpin is elliptical. Intermediate data for specifying the shape in a state where the eye angle around the center is rotated by 90 degrees is calculated, and a correction value for each rotation phase angle of the work is calculated based on this data. Based on this 褕正 value Dzu Rere A grinding method using a CNC grinder, characterized in that the grinding is performed so that the crankpin is finished.

4. The work (w) is moved to a specific center line by the work supporting rotation means (6, 7).

(9) When rotating the workpiece, during this rotation, while grinding the work while moving the grinding wheel (10) in the radial direction of the work rotation to correspond to the finish shape and dimensions of the work, near the finish dimensions of the work After grinding to the point of rotation (a) corresponding to each rotation phase angle within one rotation range of the work, the measurement means is used to measure the grinding location (a). From this measurement result, filter processing is performed to remove the surface roughness component of the ground surface. A grinding method using a CNC grinding machine, wherein a correction value for each rotation phase angle is calculated from the processing result, and finish grinding of the workpiece is performed based on the positive value.

5. The work (w) is rotated around the specific center line (9) by the work supporting rotation means (6, 7), and during this rotation, the grinding wheel (10) is adjusted to correspond to the finished shape and dimensions of the work. When grinding the workpiece while moving it in the radial direction of the workpiece, the workpiece is ground to near the finished dimension of the workpiece, and a z / ° cutout is executed. After the end of the spark-quart, the grinding means (a) corresponding to each rotation phase angle within one rotation range of the work is measured by the measuring means, and from this measurement result, the correction value for each rotation phase angle is calculated. A grinding method using a CNC grinding machine, which performs finish grinding of a workpiece based on the correction value.