JP3731715B2 - How to create cylindrical cross-section contour data - Google Patents

Description

[0001]
[Industrial application fields]
In the present invention, for example, the crankshaft is rotated around the C axis that coincides with the center of the journal, and the rotary grinding tool is advanced and retracted along the X axis that coincides with the radial direction of the crankshaft according to the planetary rotation phase of the crankpin. The present invention relates to a method for creating cylindrical cross-section contour processing data in C-X axis control processing in which a crankpin is ground by grinding or grinding is performed by controlling the cutting of a grindstone in accordance with the rotation angle of a simple cylindrical workpiece.
[0002]
[Prior art]
The crankshaft is rotated around the C axis that coincides with the center of the journal, and the grinding wheel is moved back and forth along the X axis that coincides with the radial direction of the crankshaft according to the planetary rotation phase of the crankpin to cylindrically grind the crankpin. CX controlled grinding methods are known.
When realizing this processing method, first, theoretical CX data (theoretical contour data) is defined that defines the planetary rotation angle of the crankpin and the advance / retreat position of the grinding wheel for grinding the crankpin into a perfect circle. . This theoretical C-X data is obtained by performing geometric calculations based on specifications such as workpiece finish diameter, crankpin eccentricity, grinding wheel diameter, etc., and crankshaft, tool, machine deformation and servo system It is obtained without considering various factors such as follow-up delay. Subsequently, according to the theoretical C-X data, the crankpin is subjected to trial grinding, and the roundness of the crankpin after trial grinding is measured by a measuring device. The cross-sectional contour of the crankpin after this trial grinding is usually elliptical due to the anisotropic characteristics of rigidity in all directions of the crankshaft.
Next, based on the measurement data, a correction amount for correcting the ellipse into a perfect circle is obtained for all angle phases for each unit angle (for example, 0.5 degrees) of the crankpin, and the theoretical amount of C1X is calculated based on this correction amount. The corrected C-X data is obtained by correcting the data.
Further, the trial grinding is performed again using the corrected C-X data, and the measurement is performed again. If the crankpin becomes an ellipse after this trial grinding, the corrected C-X data is corrected again and re-corrected C-X data is created.
In this way, the final C-X data that can finally grind the crank pin into a perfect circle is created by repeatedly performing the correction process of the theoretical C-X data together with several trial grindings. And in normal grinding, the process with good roundness can be performed by using the final CX data.
[0003]
[Problems to be solved by the invention]
In the conventional C-X data generation method, when the roundness of the crankpin is transferred to the measuring device after the trial grinding and measured, the measurement start angle phase origin of the crankpin on the measuring device is set as the crank on the grinder. This is done in accordance with the pivot angle origin of the pin. In this case, in a crank pin of a type in which key grooves and lubricating oil holes are formed on the surface, both origins can be easily identified based on these key grooves and oil holes.
However, in the case of a crankpin without a keyway or oil hole, it is difficult to collate both origins, and it is possible to accurately extract the correction amount for each angle phase for correcting the ellipse to a perfect circle and to calculate this correction amount. It becomes difficult to correctly assign the theoretical C-X data, and as a result, it is difficult to create corrected C-X data. Further, even if the keyway or the like has been processed, if the processing accuracy is poor, the two origins cannot be matched correctly, and it is difficult to create highly accurate correction C-X data.
[0004]
Accordingly, an object of the present invention is to eliminate the above-mentioned problems, insert index formation data into theoretical contour machining data, and form an index for specifying the angular phase of the workpiece on the contour of the workpiece cross section after trial machining. Another object of the present invention is to provide a method for creating cylindrical cross-section contour processing data that facilitates the creation of accurately corrected cylindrical cross-section contour processing data.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a method for creating cylindrical cross-section contour processing data according to the present invention controls an advancing and retreating position of a grinding or cutting tool according to theoretical contour data in accordance with the rotational phase of a cylindrical cross-section workpiece, thereby controlling an unmachined work After the trial machining, the contour of the workpiece cross section after this trial machining is measured to determine the roundness error, and the theoretical contour data is corrected by this error, and the cylindrical cross section contour machining data for machining the workpiece into a perfect circle is obtained. In the creation method, index formation data is inserted into the theoretical contour data, and one or more indices for specifying the angular phase of the workpiece are formed on the contour of the workpiece cross section after the trial machining. It is what.
[0006]
In addition to the features described above, the method for creating cylindrical cross-section contour processing data according to the present invention is such that the index formation data includes a plurality of indices formed at unequal intervals in the circumferential direction on the contour of the workpiece after trial machining. It is characterized by the above.
[0007]
Furthermore, the cylindrical cross-section contour processing data in the method of creating cylindrical cross-section contour data of the present invention is used for grinding a crankpin that is rotated on a planet on an orbit deviated from the center of rotation.
[0008]
Furthermore, the cylindrical cross-section contour processing data in the method for creating cylindrical cross-section contour processing data of the present invention is characterized in that it is used for grinding using a cylindrical portion rotated on its own axis as a workpiece.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The method for creating cylindrical cross-section contour processing data according to the present invention is to test the unprocessed workpiece by controlling the advancing / retreating position of the grinding or cutting tool according to the theoretical contour data according to the rotational phase of the cylindrical cross-section workpiece, and after this trial processing In the method of calculating the roundness error by measuring the contour of the workpiece cross section, correcting the theoretical contour data based on this error, and creating cylindrical cross section contour processing data for processing the workpiece into a perfect circle, the theoretical contour Since the index formation data is inserted into the data, and one or more indices for specifying the angular phase of the workpiece are formed on the contour of the workpiece cross section after the trial machining, the measurement data after the trial machining Thus, the rotational phase reference can be made, and the roundness error can be easily corrected to the exact rotational phase position of the theoretical contour data.
[0010]
Further, the index formation data in the method for creating cylindrical cross-section contour processing data of the present invention can be configured to form a plurality of indexes in the circumferential direction on the contour of the workpiece after the trial machining, By making multiple indices formed at irregular intervals in the circumferential direction, when measuring the contour of the workpiece cross section after trial machining on the measuring device, it is easy to collate with the rotation origin, and accurate Cylindrical section contour processing data can be created.
[0011]
Further, the cylindrical cross-section contour processing data in the method of creating cylindrical cross-section contour data of the present invention is used for grinding a crankpin that is planetarily rotated on an orbit deviated from the center of rotation, and rotates on its own axis. It is used for grinding using a cylindrical portion as a workpiece. As described above, the cylindrical cross-section contour processing data created by the method of creating the cylindrical cross-section contour data of the present invention is crank pin grinding, or a crank journal portion that is a work of a cylindrical portion rotated on its own axis, Generally, it is used for grinding a cylinder, but such processing is not limited to grinding with a grinding tool such as a grinding wheel, and may be used for cutting with a cutting tool such as a cutting tool or a rotary cutter.
[0012]
In addition, the method of creating the cylindrical cross-section contour processing data of the present invention is a trial machining of an unmachined workpiece controlled according to the theoretical contour data, and after measuring the contour of the work cross-section after this trial machining to determine the roundness error, The theoretical contour data is corrected by this error to create corrected contour data. If a desired roundness processing cannot be obtained by one correction, the contour data correction work is 1 You may perform the correction | amendment work of the 2nd time or more instead of only the degree.
[0013]
【Example】
An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a crankshaft pin portion (crank pin) for carrying out the method for creating cylindrical section contour processing data of the present invention and the cylindrical section contour processing data created by the method for creating cylindrical section contour processing data of the present invention. 1 shows an overall crankpin grinding apparatus for performing cylindrical grinding. As shown in FIG. 1, the crankpin grinding apparatus has a table 2 slidably mounted in a lateral direction (Z-axis direction) on guides 3, 3 provided in the lateral longitudinal direction of the bed 1. ing. On the table 2, a headstock 7 and a tailstock 8 are provided at opposite ends of the table 2, and a main shaft drive motor 9 for driving a work rotation is provided on the headstock 7 and provided at the end of the main shaft. The shaft end of the crankshaft W, which is a workpiece, is gripped and rotated by a chuck or the like, and the tailstock 8 is configured to support the shaft core of the crankshaft W by its center. Therefore, since the journal portion of the crankshaft W is gripped coaxially with the main shaft axis, the crankshaft W is controlled to rotate around the axis of the journal portion (C axis), and the crank pins CP1, CP2 The portion is planetarily rotated on an orbit eccentric from the rotation center of the journal portion.
[0014]
A Z-axis feed screw 4 is disposed on the bed 1 in the lateral direction (Z-axis direction), and the table 2 can be slid in the lateral direction (Z-axis direction) by a table drive motor 5 provided at the left end thereof. . By moving the table 2 in the Z-axis direction, the positions of the different crank pins CP1, CP2 are aligned and indexed with respect to the grinding wheel 15.
[0015]
X-axis guides 11 and 11 are provided in a direction (X-axis direction) orthogonal to the sliding direction (Z-axis direction) of the table 2, and a rotary grinding wheel is slidable on the X-axis guides 11 and 11. A grinding wheel base 10 having a wheel 15 is placed, and the grinding wheel 15 can be moved in a direction orthogonal to the axis of the crankshaft W (X-axis direction) by the X-axis feed screw 12 and the grinding wheel base driving motor 13. Has been. The grinding wheel base 10 is naturally provided with a drive motor (not shown) for rotating the rotary grinding wheel 15. As the grinding wheel base drive motor 13, the table drive motor 5, and the spindle drive motor 9, servo motors equipped with encoders 14 and 6 are used so that they can be controlled and rotated based on a program. The encoder of the motor 9 is not shown.
[0016]
The crankpin grinding apparatus includes a numerical control device 20, and the numerical control device 20 stores in advance a machining operation program 60 and theoretical contour data for machining the crankpin via the input / output device 21. Has been. Further, an area for storing the corrected contour data 1 based on the grinding error after the first trial grinding and an area for storing the corrected contour data 2 after the subsequent trial grinding are prepared in the memory.
Based on the contour data, the CPU 22, the interface 23, the spindle drive (C axis) motor control circuit 16, the grinding wheel base drive motor (X axis) control circuit 18, and the table drive motor (Z axis) control circuit 17 are used. The spindle drive motor 9, the grindstone drive motor 13 and the table drive motor 5 of the crankpin grinding apparatus are controlled and driven.
Therefore, the numerical controller 20 drives the table drive motor 5 to index the table 2 so that the position of the crankpin CP1 is aligned with the position of the grinding wheel 15, and the spindle drive motor 9 rotates the crankshaft W. The crankpin CP1 is ground by controlling and driving the grinding wheel base drive motor 14 so that the grinding wheel 15 is brought into contact with the shape position corresponding to the planetary rotation phase of the crankpin CP1 that rotates in a planetary manner. is there.
[0017]
The machining operation program 60 for executing the grinding cycle stored in the numerical control device 20 is such that the CPU moves the table in response to the machining start command and selectively indexes the crankpins sequentially in front of the grinding wheel 15. The grinding feed process of FIG. 4 is executed at the index position. That is, in the grinding feed process, as shown in FIG. 4, the grindstone is fast-forwarded toward the workpiece W, and is switched to the coarse grinding feed at a time point a when the outer diameter of the workpiece W including the machining allowance e is approached. At the time point b, switching to the finish grinding feed is performed, and after the spark crush grinding is performed at the time point c when the predetermined dimension is reached (d), it is performed in a known grinding feed process for quickly returning the grindstone.
[0018]
FIG. 2 shows a corrected contour data creation process performed by a process manager or an operator in order to realize a method for creating cylindrical section contour processing data. The theoretical contour data creation (step 31) and grinding processing execution (step 33, step 40) in FIG. 2 are automatically executed.
With reference to FIG. 2, the process of creating corrected contour data will be described.
In step 31, theoretical contour data is created. The theoretical contour data 24 is obtained by specifying specifications such as a grinding wheel diameter, a crankpin finish diameter, a crankpin stroke (an eccentric amount of the pin center relative to the journal center), and the like. It is calculated by a computer by substituting into the calculation formula, and defines a correspondence relationship between each angle phase of the crankpin and the cutting position of the grinding wheel for each unit rotation angle (for example, 0.5 degrees) of the crankpin, Positions X0 and X1 of the grinding wheel 15 in the X-axis direction with respect to angles C0, C1, C2, C3... Cn (for example, every 0.5 degrees) of the rotation phase (C-axis) with respect to the rotation origin shown in FIG. , X2, X3,... Xn are C-X axis control data. This data is calculated online by the CPU 22 in FIG. 1 or calculated by an offline computer, and is stored in the memory of the numerical controller 20.
[0019]
Next, following the creation of the theoretical contour data, in step 32, index formation data for forming an index convex portion at a constant angle phase with respect to the rotation phase origin of the workpiece is inserted into the theoretical contour data. This is to insert index formation data so as to form index convex portions m1, m2, and m3 having a height of 10 μm at three locations on the surface of the crankpin portion W shown in FIG. 6 (A). The angular position at which the convex portion is inserted may be a predetermined angular position with respect to the rotation origin, and the interval between each may be an equiangular distribution, but preferably an unequal angle to ensure that the phase of the crankpin can be specified reliably. Allocation. Moreover, the angular width of each convex part shall be about 5-10 degree | times.
[0020]
Subsequently, in step 33, as schematically shown in FIG. 5, the workpiece (CP1) is rotated based on the grinding feed process shown in FIG. 4 according to the theoretical contour data into which the index formation data is inserted. The workpiece is trial-ground by controlling the forward position of the grinding wheel 15 while controlling. In the CX simultaneous control grinding, the grinding wheel 15 moves forward and backward by a distance Sp twice the eccentric amount of the crankpin with respect to the journal center while the crankpin (CP1) makes one rotation, and the forward and backward stroke position is cut. By gradually shifting forward by the amount Id. Test grinding of the workpiece CP1 is executed.
What was trial-grinded in this way shows the contour shape of the workpiece cross section as shown in FIG. In particular, as in the case of crankpins, the contour of the workpiece cross section becomes an ellipse due to the rigidity anisotropy of one type of workpiece, but it is the same as the angle phase in which the index formation data is inserted into the theoretical contour data. Index convex portions m1, m2, and m3 appear at the phase position.
[0021]
Next, in step 34, the contour of the workpiece ground by trial grinding is measured. That is, the workpiece is transferred to a measuring device (not shown) and its contour is measured. In this case, the contour measurement determines the measurement start phase based on the index convex portions m1, m2, and m3, and the true phase at each angle phase that rotates by a predetermined unit angle (for example, 0.5 degrees) from the measurement start phase. The error α with respect to the circle is plotted, and error data is extracted (step 35).
That is, since each index convex part m1, m2, m3 has a clear phase relationship from the rotational phase origin, as schematically shown in FIG. 3, the rotational phase (C axis) angles C0, C1, C2, C3 ... It is possible to extract perfect circle errors α0, α1, α2, α3.
[0022]
Next, in step 36, it is determined whether or not the maximum value of the true circle error measured in step 34 is smaller than the allowable value + β. Here, β is set as an amount of ellipse as a guideline that can reduce the ellipse component to an allowable value or less when the perfect circle error is corrected. As a result of the determination, if the maximum value of the true circle error is smaller than the allowable value + β, the process proceeds to step 38, and the index formation data is deleted from the theoretical contour data.
[0023]
Next, at step 39, as schematically shown in FIG. 3, the true circle errors α0, α1, α2, α3,. .., Xn, and the position X0 + α0 of the grinding wheel 15 in the X-axis direction with respect to the rotational phase (C-axis) angles C0, C1, C2, C3,. X1 + α1, X2 + α2, X3 + α3,... Xn + αn is used to create error-corrected contour data in which a true circle error is corrected. Then, the error-corrected contour data is stored as corrected contour data 1 (25) in the memory of the numerical controller 20.
[0024]
Next, the process proceeds to step 40, where an unmachined workpiece is ground in the same manner as the previous trial grinding as shown in FIG. 5 according to the error-corrected contour data, and the roundness of the ground workpiece is measured (step). 41). In this measurement, since the index convex portions m1, m2, and m3 are not formed on the workpiece, only the roundness is measured regardless of the phase of the workpiece by, for example, an unillustrated sizing device on the machine. In this case, the contour of the workpiece is generally a perfect circle as shown in FIG.
Next, in step 42, it is determined whether or not the maximum value of the true circle error is less than or equal to an allowable value, and if it is less than or equal to the allowable value, the aforementioned error-corrected contour data is determined as final corrected contour data ( Step 44), the process of creating the corrected contour data is completed. The error-corrected contour data is stored as corrected contour data 2 (26) in the memory of the numerical controller 20 of FIG. The corrected contour data 2 is then used in continuous grinding of the same kind of workpiece.
On the contrary, if the error is not less than the allowable value in step 42, the process proceeds to step 43, the index formation data is inserted into the corrected contour data, the process returns to step 33, and the unmachined workpiece is ground. Thereafter, the true circle error is extracted again, the error-corrected contour data is corrected again, and each step is repeated in the same manner as described above.
[0025]
If the maximum value of the error is larger than the allowable value + β in step 36, error-corrected contour data with the index formation data inserted is created in step 37, and the error-corrected contour data is generated according to the error-corrected contour data. In step 33, as described above, the unmachined workpiece is ground in the same manner as in the previous trial grinding as shown in FIG. 5, and the contour of the workpiece after grinding is measured in the same manner as the measurement after the first trial grinding. (Step 34). Further, in step 36, it is determined whether or not the maximum value of the true circle error is equal to or less than the allowable value + β. By repeating such processing, the maximum value of the true circle error becomes equal to or less than the allowable value + β in step 36, so step 38 is executed as described above. Note that in the determination in step 36, errors due to the index convex portions m1, m2, and m3 are ignored.
[0026]
(Second embodiment)
In the second embodiment, CX controlled grinding is performed in which a simple cylindrical workpiece and a journal portion of a crankshaft are ground to a perfect circle by controlling the advancing and retreating movement of the grinding wheel while controlling the rotation angle on these cylindrical axes. It is the example which applied this invention to the production method of the cylindrical cross-section outline processing data for this.
In this method of creating cylindrical cross-section contour data, the correction amount for each unit angle in the first theoretical contour data is set to zero at all angle phase positions, and index formation data is inserted at predetermined angle phase positions.
Therefore, during the first trial grinding, the grinding wheel is not moved back and forth, and is simply advanced by the cutting amount Id. At the end of grinding when the grinding wheel advances by the cutting amount Id, the workpiece cross section is caused by the anisotropy of the workpiece rigidity. As shown in the schematic diagram of FIG. 7 as the outline of the white portion, the outline of is an ellipse having a maximum radius component of Sp.
In the measurement after the first trial grinding, the radius component Sp of the ellipse at each angle phase is extracted. Therefore, the radius component Sp of the ellipse is added to or subtracted from the data of the corresponding angle phase in the theoretical contour data. Is corrected, and corrected contour data is created. In the measurement, since the index convex portion based on the index formation data appears on the elliptical contour, this convex portion can be used as a reference when adding / subtracting the correction amount to / from the theoretical contour data, and the correct correction amount is assigned. Error-corrected contour data can be created.
In trial grinding according to the error-corrected contour data, grinding is performed while the grinding wheel is advanced and retracted by an elliptical radius component Sp during one rotation of the workpiece, and this forward / backward stroke is gradually shifted forward by the cut amount 1d.
[0027]
(Other examples)
In the above embodiment, an example of a grinding apparatus using a grinding wheel as a machining tool is shown as the method for creating cylindrical cross-section contour processing data of the present invention, but a rotary cutting tool or a bite is used instead of the grinding wheel. The present invention can also be applied to a cutting apparatus. As an index, not only a convex part but a concave part can be implemented.
[0028]
【The invention's effect】
The method for creating cylindrical cross-section contour processing data according to the present invention is to test the unprocessed workpiece by controlling the advancing / retreating position of the grinding or cutting tool according to the theoretical contour data according to the rotational phase of the cylindrical cross-section workpiece, and after this trial processing In the method of calculating the roundness error by measuring the contour of the workpiece cross section, correcting the theoretical contour data based on this error, and creating cylindrical cross section contour processing data for processing the workpiece into a perfect circle, the theoretical contour Since the index formation data is inserted into the data, and one or more indices for specifying the angular phase of the workpiece are formed on the contour of the workpiece cross section after the trial machining, the measurement data after the trial machining Thus, the rotational phase reference can be made, and the roundness error can be easily corrected to the rotational phase position corresponding to the theoretical contour data accurately. Therefore, accurate cylindrical cross-section contour processing data can be created even if the workpiece does not have a key groove or the like that serves as a reference for the rotational phase, and an operation for setting the rotational phase reference on the measuring apparatus as in the prior art becomes unnecessary.
[0029]
Further, the index formation data in the method for creating cylindrical cross-section contour processing data of the present invention can be configured to form a plurality of indexes in the circumferential direction on the contour of the workpiece after the trial machining, By making multiple indices formed at irregular intervals in the circumferential direction, when measuring the contour of the workpiece cross section after trial machining on the measuring device, it is easy to collate with the rotation origin, and accurate Cylindrical section contour processing data can be created.
[0030]
Furthermore, the cylindrical cross-section contour processing data in the method of creating the cylindrical cross-section contour data of the present invention is used for grinding a crankpin that is planetarily rotated on an orbit eccentric from the rotation center, or rotates on its own axis. By using the cylindrical portion to be ground for the workpiece, it is possible to easily and easily process a high-precision crankpin, cylinder or the like.
[Brief description of the drawings]
FIG. 1 is a plan view of a grinding apparatus showing an example to which a method for creating cylindrical cross-section contour processing data according to the present invention is applied.
FIG. 2 is a flowchart showing an execution process of a method for creating cylindrical section contour processing data according to the present invention.
FIG. 3 is an explanatory diagram of contour data used in a method for creating cylindrical cross-section contour processing data according to the present invention.
FIG. 4 is a conceptual diagram showing a grinding feed process used in the method for creating cylindrical cross-section contour processing data of the present invention.
FIG. 5 is a conceptual diagram showing a crankpin grinding process used in the method for creating cylindrical cross-section contour processing data of the present invention.
FIG. 6 is a conceptual diagram showing a trial grinding process used in the method for creating cylindrical cross-section contour processing data of the present invention.
FIG. 7 is a conceptual diagram showing a cylindrical grinding process used in the method for creating cylindrical cross-section contour processing data of the present invention.
[Explanation of symbols]
1: Bed 2: Table 5: Table drive motor 9: Spindle drive motor 10: Wheel head 13: Wheel head drive motor 15: Wheel wheel 16: Spindle drive motor control circuit 17: Table drive motor control circuit 18: Wheel head drive motor Control circuit 24: theoretical contour data 25: corrected contour data 1
26: Corrected contour data 2
W: Workpiece (crankshaft)
CP1, CP2: Crank pins m1, m2, m3: Index convex part

Claims (4)

By controlling the advancing and retreating position of the grinding or cutting tool according to the theoretical contour data according to the rotational phase of the cylindrical cross-section workpiece, trial machining is performed on the unmachined workpiece, and after this trial machining, the contour of the workpiece cross-section is measured to reduce the roundness error. In a method for obtaining cylindrical cross-section contour processing data for processing the workpiece into a perfect circle by correcting the theoretical contour data by this error,
A cylindrical cross-sectional contour in which index formation data is inserted into the theoretical contour data, and one or more indexes for specifying the angular phase of the workpiece are formed on the contour of the workpiece cross-section after the trial machining. How to create machining data. 2. The cylindrical cross-section contour processing data according to claim 1, wherein the index formation data is formed such that a plurality of indexes are formed at unequal intervals in the circumferential direction on the contour of the workpiece after trial processing. How to create 3. The method of creating cylindrical cross-section contour data according to claim 1, wherein the cylindrical cross-section contour processing data is used for grinding a crankpin that is planetarily rotated on an orbit eccentric from a rotation center. 3. The method of creating cylindrical cross-section contour processing data according to claim 1 or 2, wherein the cylindrical cross-section contour processing data is used for grinding using a cylindrical portion rotated on its own axis as a workpiece.

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