JP2015123569A - Gear grinding correction data creation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for correction of gear grinding correction data by which correction data for grinding data can be so corrected as to be able to finish processing of a tooth surface as desired.SOLUTION: A method for correction of gear grinding correction data comprises: a phase direction correction data creation process in which a shape of a tooth surface of a work-piece 20 after processing is measured, shape data is superimposed and balanced at a point of being simultaneously processed by a thread-shaped grinding stone 10 as a reference by converting a length of the work-piece in a tooth width direction into a Z-axis direction position of a grinding processor, and the balanced data is reversed thereby creating phase correction creation data; and a notching direction correction data creation process in which phase shape correction data, in which the shape data is corrected by the phase correction data, is created, the phase shape correction data is superimposed and balanced, and the balanced data is converted into data in a notching direction thereby creating notching correction data.

Description

  The present invention relates to a method for creating gear grinding correction data, and more particularly to a method for creating correction data for grinding data when a gear is ground by using a threaded grindstone.

  Finishing of the gear using the threaded grindstone is performed by traverse grinding. In traverse grinding, the phase relationship between the thread of the threaded grinding wheel and the tooth gap of the gear to be ground (workpiece) and the depth of cut (grinding amount of the tooth bottom) are set according to the traverse position. The surface shape can be finished to a desired shape such as a crowning shape.

  Patent Document 1 describes a method for finishing a desired tooth surface by performing cutting, traverse, and phase correction grinding in a traverse grinding of a gear using a threaded grindstone. Patent Document 2 describes a method for creating grinding data that defines a grinding amount based on a desired tooth surface shape.

Japanese Patent No. 3980375 Japanese Patent No. 3980376

  However, in practice, even if grinding data based on the desired shape is set due to the bending of the threaded grinding wheel, gears, grinding machine, etc. due to the machining load, or errors in the machining operation, the finished tooth surface Causes a shape error. In order to eliminate the tooth shape error, it is necessary to correct the grinding data in consideration of the error. Conventionally, an operator sets a correction value for grinding data based on tooth surface shape data obtained by measuring a processed gear with a measuring machine.

  The shape error of the tooth surface varies depending on the position in the tooth height direction, the tooth surface direction, and the like, and it is necessary to set a correction value for each traverse position in consideration of this point. However, conventionally, there is no method for calculating an appropriate correction value, and the setting of the correction value depends on the experience of the operator. Therefore, it is necessary to repeat the processing and the confirmation of the processing result until an appropriate correction value is set, and much time is consumed and many gears are wasted, resulting in poor efficiency.

  In view of the above, an object of the present invention is to provide a gear grinding correction data creation method capable of creating correction data for grinding data so that a desired tooth surface can be finished.

  The gear grinding correction data creation method of the present invention is configured to rotate the gear and the threaded grinding wheel synchronously while meshing the thread of the threaded grinding wheel of the grinding machine with the gear to be ground, and the tooth surface of the gear A gear grinding correction data creation method for creating correction data for grinding data that defines a grinding amount when grinding a wheel, wherein the shape data is measured by measuring the shape of the tooth surface of the gear processed with the grinding data. The length in the tooth width direction is converted into the Z-axis direction position of the grinding machine, averaged by superimposing the points simultaneously processed by the threaded grindstone, and the averaged data is inverted. A phase direction correction data creation step for creating phase correction data, and phase shape correction data obtained by correcting the shape data with the phase correction data are created, and the phase shape correction data are overlapped and averaged, The serial averaged data in terms of cutting direction of the data, characterized in that it comprises a cutting direction correction data creating step of creating cut correction data.

  According to the gear grinding correction data creation method of the present invention, correction data capable of averaging and correcting the tooth surface shape error that differs depending on each measurement position based on the shape data of the gear to be ground after processing. Can be created. Therefore, if this correction data is used, it is possible to minimize the tooth surface shape error without depending on the operator's experience or the like.

  The gear grinding correction data creating method of the present invention preferably includes a step of correcting the phase shape correction data with an approximate curve approximating the phase shape correction data.

  In this case, since the corrected phase shape correction data does not have a steep inflection point or the like, it is possible to suppress a sharp fluctuation in grinding. It is also possible to obtain correction data outside the measurement range.

  In the gear grinding correction data creation method of the present invention, it is preferable that the value of the phase correction data is set to “0” from the air cut start point to the air cut end point in the tooth trace direction of the threaded grindstone.

  In this case, it is possible to eliminate the possibility of adversely affecting the processing accuracy.

The figure explaining the grinding finishing process of the workpiece | work using a screw-shaped grindstone. The flowchart explaining the gear grinding correction data creation method which concerns on embodiment of this invention. The figure explaining inconsistency of a pitch point locus and a measurement point locus. (A)-(f) is a figure explaining the procedure which calculates phase correction data in order. The figure explaining the position where the screw thread of a thread-like grindstone meshes with the tooth gap of a work in a certain time. (A), (b) is a figure explaining the procedure which calculates cutting correction data in order.

  First, with reference to FIG. 1, the grinding finishing process of the gear 20 (henceforth a workpiece | work) 20 for grinding using the screw-shaped grindstone 10 of a grinding machine is demonstrated.

  The workpiece 20 is rough-processed in advance to an approximate gear shape. The threaded grindstone 10 has a thread 11 formed in a spiral on the outer peripheral surface thereof. Then, the threaded grindstone 10 and the work 20 are rotated synchronously while the thread 11 of the threaded grindstone 10 is engaged with the tooth groove 21 of the work 20, and the tooth surface of the work 20 is ground to a desired shape.

  Although details are not described, the workpiece 20 can be driven to rotate around its axis by a rotary motor. The threaded grindstone 10 can also be driven to rotate around its axis by a rotary motor. The rotation axis of the workpiece 20 is inclined by a predetermined angle with respect to the rotation axis of the threaded grindstone 10. This inclination angle is set so that the thread of the threaded grinding wheel 10 coincides with the tooth trace direction of the workpiece 20, that is, the tooth width direction.

  The workpiece 20 can be moved independently in the X-axis direction, the Y-axis direction, and the Z-axis direction by a moving mechanism such as a slide table. By adjusting the position of the workpiece 20 in the XYZ axial direction with respect to the threaded grinding wheel 10, the meshing between the thread 11 of the threaded grinding wheel 10 and the tooth groove 21 of the workpiece 20 changes, and the tooth surface of the workpiece 20 after grinding is completed. The shape is determined. The relative positional relationship between the threaded grinding wheel 10 and the workpiece 20 may be adjusted independently in the X-axis direction, the Y-axis direction, and the Z-axis direction, and the threaded grinding wheel 10 can be moved with respect to the workpiece 20. Also good.

  The grinding finish processing of the workpiece 20 using the threaded grinding wheel 10 may use a conventional grinding machine as described in Patent Documents 1 and 2, for example.

  When such a grinding machine is used to finish the workpiece 20 using the threaded grindstone 10, the relative grinding position of the threaded grindstone 10 with respect to the workpiece 20 is determined in the X-axis direction, the Y-axis direction, and An operator or the like sets grinding data defined in the Z-axis direction in the grinding machine.

  Grinding data in the X-axis direction is the depth of cut, and grinding data in the Y-axis direction is the phase (relative movement amount based on the point where the center line of the thread of the threaded grinding wheel coincides with the center line of the tooth groove of the workpiece. The Z-axis grinding data defines the traverse position (the tooth trace direction of the workpiece 20, that is, the position in the tooth width direction).

  By the way, the grinding data set according to the desired shape on the actual tooth surface of the workpiece 20 after finishing due to the bending of the threaded grinding wheel 10, the workpiece 20, and the grinding machine due to the machining load or errors in the machining operation. An error will occur. In order to eliminate the tooth shape error, it is necessary to correct the grinding data in consideration of the error.

  The gear grinding correction data creation method according to the embodiment of the present invention will be described below with reference to FIG. In this gear grinding correction data creation method, a calculation program is prepared in accordance with the procedure for calculating correction data described below, and the shape data of the workpiece 20 after processing is obtained by using a computer such as a commercially available PC. Can be implemented.

  First, as a preparation stage, the shape of the tooth surface of the workpiece 20 finished with a grinding machine is measured (STEP 10). For the measurement, a contact-type shape measuring machine or the like may be used as in the conventional case. In the measurement, the tooth surface shape is discretely measured at a preset measurement position to obtain a point data group. Here, with respect to the left and right sides of all teeth of the workpiece 20, each of the tooth heights at the top (tooth tip), middle, and bottom (tooth base) of the tooth is divided into a plurality, for example, 16 in the tooth width direction. Get position data at a point.

  In this stage, a phase correction data calculation step is performed (STEP 20). According to the change of the grinding data in the phase direction, that is, the Y-axis direction, the shapes of the left and right sides of the teeth of the workpiece 20 after processing do not change regularly. Therefore, in the phase correction data calculation step, correction phase correction data that can averagely correct the shapes of the left and right sides of the teeth of the workpiece 20 as a whole is calculated.

  In the phase correction data calculation step, first, the average position of the teeth of the workpiece 20 in each tooth height direction is obtained (STEP 21).

  In the measurement of the shape of the tooth surface of the workpiece 20, the measurement point of the gear is determined according to the measurement standard of the gear, and usually, the mesh point with other gears and the functionally important pitch point is included in the measurement point. . However, as shown in FIG. 3, since the workpiece 20 is finished by dislocation grinding, the pitch point cannot always be a measurement point.

  Therefore, here, the points on the top (tooth tip), middle portion, and bottom (tooth base) of the tooth on the right side of the tooth of the workpiece 20 are set as measurement points. However, these points are merely examples, and other points may be included or a part thereof.

  In Fig.4 (a), it has shown as line 101R-103R, 101L-103L which connected the average position in each height direction for description. 4 (a) to 4 (d), reference numerals 101R, 102R, and 103R represent lines related to the top, middle, and bottom of the right side of the teeth of the workpiece 20, and reference numerals 101L, 102L, and 103L represent the respective lines. Lines relating to the top, middle and bottom of the left side of the teeth of the workpiece 20 are shown. 3 (4) to FIG. 4 (d), only three lines are shown for each of the left and right tooth surfaces, but in reality, the number of teeth is the same as the number of teeth of the workpiece 20. However, only some of the teeth of the workpiece 20 may be used.

  By the way, each tooth | gear of the workpiece | work 20 differs in the position grind | polished with the thread of the screw-shaped grindstone 10 at a certain time according to tooth height. As shown in FIG. 5, the position of the thread 11 of the threaded grinding wheel 10 with which the tooth groove of the workpiece 20 meshes is along the inclined straight line A. Therefore, at a certain point in time, when the relative positional relationship between the threaded grinding wheel 10 and the workpiece 20 in the Z-axis direction is changed, the tooth groove of the workpiece 20 to be ground by meshing with the thread 11 of the threaded grinding wheel 10 is obtained. It varies for a large number of teeth along the straight line A. Therefore, when obtaining correction data, it is necessary to consider so that the shape of the tooth surface along the straight line A is appropriately corrected.

  Therefore, next, as shown in FIG. 4B, the lines 101R to 103R and 101L to 103L in the respective tooth height directions are aligned with respect to the straight line A in the tooth width direction (STEP 22).

  Further, as shown in FIG. 4 (c), the lines 101R to 103R and 101L to 103L in the respective tooth height directions are matched in the tooth height direction. For example, the positions of the lines 101R to 103R and 101L to 103L on a certain straight line A are set as a reference, for example, “0” (STEP 23).

  Further, as shown in FIG. 4D, the lines 101R to 103R and 101L to 103L indicating the shapes of the left and right tooth surfaces in each tooth height direction are matched in the tooth height direction (STEP 24). Note that STEP 23 and STEP 24 may be reversed in order or simultaneously.

  Then, all the lines 101R to 103R and 101L to 103L shown in FIG. 4D are overlapped and averaged to obtain one line (not shown) (STEP 25).

  Next, the line obtained in STEP 25 is converted into the Z-axis direction position of the grinding machine by converting the length of the workpiece in the tooth width direction to obtain a line 110 shown in FIG. 4E (STEP 26).

  Then, the line 110 shown in FIG. 4 (e) is reversed in the direction of rotation of the blade 20 workpiece 20 to obtain the line 120 (STEP 27). Data indicated by the line 120 may be phase correction data.

  However, since the line 120 is actually the average of the lines 101R to 103R and 101L to 103L made of point group data, the line 120 becomes discrete point data. Therefore, the line 120 may have a sharp inflection point. Further, correction data outside the measurement range cannot be obtained.

  Therefore, it is preferable to obtain an approximate curve obtained by approximating the point data indicated by the line 120 with a multi-order curve, for example, a 6th-order curve or higher using the least square method or the like, and the data indicated by the approximate curve is used as the phase correction data ( (STEP 28).

  Next, a cut correction data calculation step is performed (STEP 30). In accordance with the change of the grinding data in the cutting direction, that is, the X-axis direction, the shapes of the left and right sides of the teeth of the workpiece 20 after processing change symmetrically. Therefore, in the cutting correction data calculation step, cutting correction data that can similarly correct the shapes of the left and right sides of the teeth of the workpiece 20 is calculated.

  In the cutting correction data calculation step, first, the shape data is corrected with the phase correction data obtained in STEP 27 or STEP 28 to create phase shape correction data (STEP 31).

  Next, the phase shape correction data are overlapped and averaged to obtain lines 201R and 201L shown in FIG. 6A (STEP 32). In FIG. 6A, for the purpose of explanation, lines 201R and 201L connecting the averaged positions of the left and right tooth surfaces of the workpiece teeth are shown.

  Then, one line shown in FIG. 6A, for example, the line 201L is inverted in the tooth height direction and overlapped with the other line 201R to obtain an averaged line (STEP 33). This line is a line in the YZ plane.

  Then, the YZ plane line obtained in STEP 33 is converted into an XY plane (see FIG. 6A) to obtain a line 210 shown in FIG. 6B (STEP 34). Data indicated by the line 210 is cut correction data.

  Incidentally, the operation of the grinding machine includes an air cut portion in which the threaded grinding wheel 10 does not contact the workpiece 20. If the correction data obtained from the approximate curve obtained in STEP 28 is applied to the air cut portion, the machining accuracy may be adversely affected. Therefore, it is preferable to set the phase direction correction value to “0” from the air cut start point to the air cut end point at the traverse position.

  Further, when a chamfered portion or the like exists on the teeth of the workpiece 20, correction data is not obtained for the range of the chamfered portion or the like, or the correction value may be set to “0”.

  As described above, according to the gear grinding correction data creation method according to the embodiment of the present invention, based on the shape data of the workpiece 20 after machining, the shape error of the tooth surface that differs depending on each measurement position is averaged and corrected. Correction data that can be calculated. Therefore, if this correction data is used, it is possible to minimize the tooth surface shape error without depending on the operator's experience or the like.

  If the tooth shape error cannot be kept within the desired range using the correction data obtained first, it is based on the tooth surface shape data until the shape error falls within the desired range. The correction data may be obtained repeatedly.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this. For example, although the spur gear workpiece 20 is illustrated, the workpiece may be a helical gear or the like.

  DESCRIPTION OF SYMBOLS 10 ... Screw-shaped grindstone, 11 ... Screw thread, 20 ... Workpiece | work (gear for grinding), 21 ... Tooth gap.

Claims (3)

Grinding that regulates the grinding amount when grinding the tooth surface of the gear by rotating the gear and the threaded wheel synchronously while meshing the thread of the threaded wheel of the grinding machine with the gear to be ground A gear grinding correction data creation method for creating correction data for data,
The shape of the tooth surface of the gear machined with the grinding data is measured, and the shape data is converted into the tooth width direction length of the gear into the Z-axis direction position of the grinding machine, and simultaneously machined with the threaded grinding wheel Are averaged by superimposing points
A phase direction correction data creation step of creating phase correction data by inverting the averaged data;
Create phase shape correction data by correcting the shape data with the phase correction data,
Superimposing and averaging the phase shape correction data,
A gear grinding correction data creating method, comprising: a cutting direction correction data creating step of creating the cutting correction data by converting the averaged data into cutting direction data.   The gear grinding correction data creating method according to claim 1, further comprising a step of correcting the phase shape correction data by an approximate curve approximating the phase shape correction data.   The gear grinding correction data according to claim 1 or 2, wherein a value of the phase correction data is set to "0" from an air cut start point to an air cut end point in a tooth trace direction of the threaded grinding wheel. How to make.

Images