JP4635143B2 - Gear finishing by synchronous drive - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gear finishing method that performs grinding while synchronously rotating a gear to be ground and a finishing forming tool by driving.
[0002]
[Prior art]
When finishing gears such as shaving and honing (including dressing), use a finishing tool such as a rotating whetstone or cutter with internal or external gears and mesh with the gear to be ground. Grinding is performed using sliding contact between the tooth surfaces.
[0003]
In a normal case, the forming tool is driven and the gear to be ground is machined in a so-called accompanying state that rotates with the forming tool under meshing with the forming tool. However, the grinding in the accompanying state does not have a mechanism for forcibly correcting the eccentricity of the gear to be ground and the accumulated pitch error, and as a result, high-precision machining is difficult.
[0004]
On the other hand, high precision can be obtained by processing while driving both the forming tool and the gear to be ground. However, for this, it is indispensable that the forming tool and the gear to be ground are synchronously rotated with high accuracy because it is necessary to mesh the teeth with zero backlash.
[0005]
Various proposals have been made to achieve high-accuracy synchronous rotation, but the tool and the gear to be ground are engaged in a stopped state, and forward and reverse rotation is repeated little by little to move in the cutting direction. In general, after obtaining the state in which the phases are matched, both are driven and rotated synchronously. For example, in the processing method according to Japanese Patent No. 3000668, the gear to be ground is rotated forward and backward by small amounts, the amount of rotational displacement at which the forming tool begins to rotate in each rotational direction is detected, and the phase shift is made zero. The position correction amount of the forming tool necessary for this is obtained, and a feed motor is fed to the forming tool based on the position correction amount to obtain synchronized rotation in phase.
[0006]
However, these methods have a drawback in that it is necessary to repeat the minute rotation of the gear to be ground in order to detect the relative position of the forming tool with the sensor, which requires labor and time.
[0007]
[Problems to be solved by the invention]
The present invention relates to a gear finishing method capable of starting rotation of a gear to be ground and a forming tool without requiring repeated repetition of minute rotation of the forming tool, which is troublesome, when finishing the gear by synchronous rotation. The purpose is to provide.
[0008]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention achieves the gear finishing that drives both the work supporting spindle supported by the machine base and the finishing forming tool to rotate synchronously when forming and finishing the gear as the work. In the machining method, the spindle and the forming tool are driven by a control motor by servo control by a servo motor or Cs control by an AC spindle motor, and the gear finishing machining method returns to the rotation direction origin of the control motor. Moving the workpiece and attaching the workpiece to the main shaft and the tailstock shaft in a rotation non-clamped state of the tailstock shaft, engaging the workpiece positioning device with the workpiece and positioning the workpiece in the rotational direction; and A step of rotating the mandrel shaft in a rotating clamp state in mesh with a workpiece positioning device; A step of setting the control motor coupled to the main shaft in a free-run state, a step of reading a phase shift of the main shaft on the control motor side of the main shaft caused by the free-run state, and a step of removing the work positioning device from the work And correcting the drive phase of one of the control motor coupled to the main shaft and the control motor coupled to the forming tool so as to eliminate the phase shift, and synchronizing the main shaft and the forming tool by each control motor. Rotating in phase with each other, bringing the spindle and the forming tool close to each other so that the workpiece and the tip circle of the forming tool cross each other, a control motor coupled to the spindle and the forming tool The drive torque of one of the control motors coupled to the control motor is such that cutting by the forming tool does not occur. The spindle and the forming tool are brought close to a position preset as zero-backlash or a position detected as zero backlash, and the control of the spindle and the forming tool at the zero backlash position. A phase shift between the motors is detected and the drive phase is corrected so as to eliminate it, and the drive phase of each control motor is fixed, and each control motor is driven with a torque required for cutting, and the spindle and the molding And a step of performing finish cutting by gradually increasing the depth of cut while rotating the tool synchronously (1st invention).
[0009]
In order to achieve the above object, the present invention also provides a gear that drives both a main spindle for supporting a work supported by a machine base and a forming tool for finishing synchronously when a gear that is a work is formed and finished. A finishing method, wherein the spindle and the forming tool are driven by a control motor by servo control by a servo motor or Cs control by an AC spindle motor. A step of engaging a tool with a slight backlash, clamping the workpiece by the spindle and a tailstock, a control motor coupled to the spindle, and a control motor coupled to the forming tool. In a state where one drive torque is reduced to such an extent that cutting by the forming tool does not occur, the main shaft and the forming tool are controlled by each control. A step of synchronously rotating by control of a motor, a step of bringing the spindle and the forming tool closer to a position preset or detected as zero backlash, and the spindle and the molding at the zero backlash position After detecting and correcting the synchronization error of each control motor with the tool, the step of fixing the drive phase, and driving each control motor with the torque necessary for cutting, and the spindle and the forming tool are rotated synchronously, and the cutting amount is adjusted. And a step of performing a finish cutting stepwise to provide a gear finishing method (second invention).
[0010]
[Action]
In the present invention, in the first invention, in grinding and finishing the gear as a workpiece, the spindle and the forming tool are driven by servo control by a servo motor or AC spindle motor by Cs control (c axis control, i.e., around the z axis). First, the control motor is moved to the rotation direction origin, and the work is attached to the spindle and the tailstock (primary phase determination).
[0011]
Then, the work positioning device is engaged with the work on the main shaft to perform positioning in the rotational direction, and the work is clamped by the main shaft and the tailstock shaft. The workpiece positioning device meshes with the workpiece so as to position the phase of the workpiece corresponding to the rotation direction origin of the main shaft (control motor rotation shaft). Even if the control motor is set at the origin, the phase of the workpiece actually deviates due to an attachment error or the like. Therefore, in this state, the main shaft is slightly twisted between the work side constrained by the work positioning device and the control motor side constrained by the control motor. When the control motor is set to a free-running state in this state, the control motor side of the main shaft slightly rotates by the amount of the twist. If the drive phase is corrected by reading the phase shift caused by this rotation and adjusting the reference position so as to eliminate the phase shift, the spindle and the forming tool are synchronized by the control of each control motor and the phase is adjusted. Can be rotated (secondary phasing). The correction of the drive phase can be performed by one of the control motor coupled to the main shaft and the control motor coupled to the forming tool.
[0012]
Therefore, in this state, the workpiece can be meshed with the forming tool while rotating with a driving force necessary for grinding, but the following operation is further performed in order to obtain more accurate phase alignment. First, the spindle and the forming tool are brought close to each other so that the workpiece and the tip circle of the forming tool cross each other. Next, in a state where the drive torque of the one control motor is reduced to such an extent that it is not subjected to cutting by the forming tool, the spindle and the forming tool are brought close to a position set in advance as a zero backlash or a detected position. In this state, a phase shift between the control motors of the spindle and the forming tool is detected, the drive phase is corrected so as to eliminate this, and the drive phase of each control motor is fixed. Thereby, the phase error which inevitably occurs between the positioning device and the forming tool can also be eliminated, and the phase of the workpiece and the forming tool can be accurately matched (tertiary phase determination).
[0013]
In this state, if each control motor is returned to the torque required for cutting and the cutting amount is gradually increased to perform cutting, it is possible to perform finish cutting with extremely high accuracy by synchronous driving.
[0014]
The phase of the forming tool is detected by an encoder that reads the position of the teeth or grooves of the forming tool. Therefore, when the forming tool is newly attached to the head, the forming tool is stopped and engaged with the workpiece on the main spindle in the manual mode, and the meshing of the entire shape of the workpiece is made uniform, and the phase of the forming tool is adjusted. Set the origin.
[0015]
In the present invention, in the second invention, the work and the forming tool are manually engaged with a slight backlash, and the work is clamped by the main shaft and the tailstock shaft. As a result, the workpiece is placed in a state in which the phase is substantially in agreement with the forming tool, and is held in a clamped state by the main shaft and the tailstock shaft. Here, since the work is performed in a state where the forming tool and the spindle are stopped, the engagement with a slight backlash is kept so as not to hinder the subsequent drive rotation.
[0016]
Next, in a state where the drive torque of one of the control motor coupled to the main shaft and the control motor coupled to the forming tool is reduced to such an extent that cutting by the forming tool does not occur, the main shaft and the forming tool are controlled by each control motor. Rotate synchronously. Thus, since one control motor is synchronously rotated with the torque reduced, one of the main shaft and the forming tool rotates (follows) with the other. In this state, the spindle and the forming tool are brought close to a position preset as zero backlash or a detected position. In this state, since one of the control motors is driven with a low torque, both control motors are in phase with each other in a state close to the intended synchronous drive. Here, the synchronization error of each control motor of the spindle and the forming tool at the position of zero backlash is detected, and after correction, the drive phase is fixed. As a result, synchronous driving with exactly the same phase becomes possible.
[0017]
In this state, if each control motor is driven with the torque required for cutting and the main shaft and the forming tool are rotated synchronously while cutting is performed while gradually increasing the cutting amount, finish cutting with extremely high accuracy by synchronous driving is performed. Can do.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. 1, 2, and 3 are a front view, a side view, and a plan view, respectively, of a gear finishing device according to an embodiment of the present invention.
[0019]
The illustrated gear finishing device is configured to hold a gear W (workpiece) W to be ground on a table 10 supported by a machine base B by a holding device. The holding device includes a head stock 30 and a tailstock 40 that are slidable on the table so as to be close to and away from each other and each have a main shaft and a tailstock shaft for supporting a workpiece. A grindstone holding device 50 is further mounted on the machine base B.
[0020]
FIG. 4 is a front view mainly showing an operation part of the gear finishing apparatus. As shown in the figure, one (left in the figure) head stock 30 is coupled to the headstock body 31 supported by the table 10, the spindle 32 rotatably supported by the headstock body, and the headstock body 31. And a drive motor 33 for rotating the main shaft 32. The other (right in the figure) tailstock 40 includes a tailstock body 41 supported by the table 10 and a tailstock shaft 42 rotatably supported by the tailstock body.
[0021]
As shown in FIG. 5, the tailstock shaft 42 includes a clamp shaft that moves forward and backward in the axial direction by a driving device (not shown) mounted on the tailstock body 41. Therefore, the workpiece W can be clamped in the rotational direction on these shafts by supporting the workpiece W by the main shaft 32 and the tailstock shaft 42 with the clamp shaft retracted and then moving the clamp shaft forward. In this example, the work drive motor 33 is a built-in AC spindle motor so as to enable the control described below.
[0022]
As shown in the figure, the grindstone holding device 50 includes a ring-shaped head 52 that is positioned between the head stock 30 and the tailstock 40 and supports the rotating grindstone 51, and a horizontal axis line perpendicular to the main shaft 32. And a holding portion 53 that is supported so as to be rotatable around. Thus, in this embodiment, the rotating grindstone 51 is used as a forming tool. As shown in FIGS. 2 and 3, the holding unit 53 includes a head drive motor 531 for rotating the head 52 about the main shaft, and a head for rotating the head 52 about a horizontal axis perpendicular to the main shaft 32. A tilt motor 532 is provided. Intermediate gears 534 and 535 mesh with a gear 533 fixed to the output shaft of the head drive motor 531, and these intermediate gears mesh with teeth provided on the outer periphery of the head 52 to drive the head 52. In this way, by driving the outer peripheral gear of the head 52 via the two intermediate gears that mesh with the drive gear, low backlash is achieved with a simple structure, and high-precision and high-speed synchronous meshing is ensured. To do. The head drive motor 531 is an AC spindle motor in this example so as to enable the control described below. A cutting drive unit 60 on the machine base is coupled to the grindstone holding device 50. The notch driving unit 60 is movable along a horizontal axis perpendicular to the main shaft 32 and the tail pushing shaft 42 by driving of the horizontal driving motor 61, and the head 52 and the rotating grindstone 51 are moved closer to and away from the workpiece on the main shaft by the movement. And incising is performed during grinding.
[0023]
The movement and rotation of the head stock 30, tailstock 40, work drive motor 33, head drive motor 531, etc. are controlled by a control device 70 having an operation panel 71.
[0024]
In the case of a gear finishing device that automatically performs the work from the replacement of the workpiece to the start of the synchronous driving of the spindle and the forming tool, a workpiece positioning device 80 is attached to the head stock 30. The workpiece positioning device performs accurate positioning in the rotation direction of the workpiece in order to obtain accurate meshing with the forming tool. For example, the workpiece positioning device can be configured as follows. As shown in FIG. 6, the workpiece positioning device 80 includes a fixing portion 81 fastened with a bolt to a workpiece mounting side end portion of the head stock 30, and an arm mounting base is slidable on a slide guide 82 on the fixing portion. 83 is installed. The arm 84 is fixed at the base end to the arm mounting base 83, and a conical protrusion 85 having a size capable of entering between the teeth of the workpiece W is attached to the distal end. Further, a driving cylinder 86 is attached to the fixed portion 81, and a piston rod 87 that cooperates with the driving cylinder 86 is coupled to the arm base end portion. Therefore, the arm 84 is driven by the drive cylinder 86, guided by the slide guide 82, and slides in the radial direction of the main shaft 32. A dock plate 88 is fixed to the fixed portion 81, and a proximity switch 89 for detecting the forward / backward end of the arm is attached to the dock plate. As a result, the arm 84 moves back and forth between a forward position where the arm 84 meshes with the workpiece W and a reverse position where the mesh is released. The protrusion 85 at the tip of the arm during advancement meshes with the teeth of the workpiece W and positions the workpiece in the rotational direction, as shown in the detailed view of part a in FIG.
[0025]
In the case of a gear finishing device that performs manual operation from the replacement of the workpiece to the start of synchronous driving of the spindle and the forming tool, the workpiece positioning device 80 can be omitted.
[0026]
As the workpiece driving motor 33 and the head driving motor 521, a control motor capable of synchronizing the rotation direction and controlling the phase accurately as described above is used, and specifically, a servo motor or an AC spindle motor.
[0027]
Next, a more detailed configuration of the gear finishing device and a procedure of a processing method based thereon will be described with respect to an embodiment based on automation and an embodiment in which manual operation is performed.
[0028]
I. When automation is performed from workpiece replacement to the start of synchronous drive of the spindle and forming tool
Hereinafter, description will be made with reference to the main part explanatory view of FIG. 7 and the flowchart of FIG. In addition, although this form is advantageous to automation of operation, manual operation can also be taken in as needed. The phase of the rotating grindstone 51 is detected by an encoder that reads the position of the teeth or grooves of the rotating grindstone. When the rotating grindstone 51 is newly attached to the head 52, the rotating grindstone is stopped and meshed with the work on the spindle in the manual mode, and the meshing of the rotating grindstone is made uniform throughout the entire circumference of the work. Set the phase origin. When the same rotating grindstone 51 is continuously used, the setting of the origin can be used as it is without stopping the rotating grindstone.
[0029]
After this preparation is completed, the work drive motor 33 of the headstock 30 is returned to the origin in the encoder, thereby bringing the work drive motor 33 into a servo lock state (step 1).
[0030]
Thereafter, the head driving motor 532 is operated to drive the head 52. The rotation speed of the head 52 is adapted to the cutting speed of the workpiece W. Thereafter, the head continues to rotate until a stop command is issued. In this state, the tailstock 40 is brought close to the headstock 30 and the work W is held by the main shaft 32 and the tailstock shaft 42. Here, the clamp shaft of the tailstock shaft 42 is in the retracted position and is in an unclamped state with respect to rotation (step 2).
[0031]
Next, the arm 82 of the workpiece positioning device 80 is moved, and the protrusion 85 is inserted between the teeth of the workpiece W, thereby positioning the workpiece W in the rotational direction. For the workpiece W on the spindle 32, the phase of the workpiece W itself and the phase of the drive motor do not necessarily match due to variations in machining accuracy of the workpiece W, distortion due to heat treatment, attachment errors to the jig, and the like. Therefore, the workpiece positioning device 80 accurately determines the phase of the workpiece W itself (FIG. 7A) (step 3).
[0032]
While the meshing state with the protrusion 85 is maintained, the clamp shaft of the tailstock shaft 42 is advanced, and the work W is fixed on the main shaft 32 and the tailstock shaft 42 in the rotational direction (step 4).
[0033]
The drive motor 33 is servo-off while maintaining the meshing state between the workpiece W and the workpiece positioning device 80. As a result, the main shaft 32 is in a free-run state in which the rotation direction is not restricted. As described above, even if the work drive motor 33 is in the origin return state, the phase of the work W on the spindle 32 in the rotational direction does not necessarily match the phase of the drive motor due to various factors. Therefore, the phase of the workpiece W is accurately determined by meshing with the workpiece positioning device 80. Therefore, normally, a slight shift in the rotational direction occurs between the workpiece W positioned by the workpiece positioning device 80 and the workpiece drive motor 33 in the return to origin position. This shift causes elastic torsional deformation between the support portion of the main shaft 32 by the work drive motor 33 and the support portion of the workpiece W. Therefore, the main shaft 32 is slightly moved so as to return torsional deformation at the place supported by the work drive motor 33 by keeping the work drive motor 33 in a free-running state while maintaining the meshed state of the work W and the work positioning device 80. (Step 5).
[0034]
A slight correction rotation amount of the main shaft 32 generated by setting the work drive motor 33 in a free-run state is read from the encoder. In this case, it is desirable to set so as to prompt the return to the initial setting by generating an abnormal signal or the like if the corrected rotation amount is excessive. The read correction rotation amount is newly stored as the origin position by the programmable controller or the macro program (FIG. 7B) (step 6).
[0035]
From this state, the workpiece positioning device 80 is retracted away from the workpiece W (FIG. 7C) (step 7).
[0036]
After the workpiece positioning device 80 moves backward, the workpiece driving motor 33 is operated to rotate the spindles 32 and 42. In parallel with this, the table 10 is moved to bring the workpiece W closer to the center of the rotating grindstone 51 (FIG. 7D) (step 8).
[0037]
While the workpiece W approaches the center of the rotating grindstone 51, the spindle 32 is synchronized and phased. That is, it is detected by the encoder coupled to the main shaft 32 and the head 52 that the main shaft 32 has reached the synchronous speed with respect to the rotating grindstone 51, and then phase alignment is performed based on the origin corrected in the above-described step 5. . In parallel with this, the cutting drive unit 60 is operated to advance the rotating grindstone 51 toward the workpiece W (in the z-axis direction) (FIG. 7E) (step 9).
[0038]
After completion of the synchronization phase alignment, the spindle 32 and the rotating grindstone 51 are brought close to each other so that the rotating grindstone 51 and both tooth tips of the workpiece W intersect each other. First, the rotating grindstone 51 is further advanced to a position where the tips of both teeth slightly mesh. At this time, in order to prevent tooth damage due to collision, it is desirable to use cutting feed instead of rapid feed (FIG. 7F) (step 10).
[0039]
After reaching the position where the tips of both teeth of the rotating grindstone 51 and the work W are sufficiently engaged with each other, the output torque of the work drive motor 33 is lowered to a level where cutting is impossible (step 11).
[0040]
Further, the rotary grindstone 51 continues to advance until the backlash between the rotary grindstone 51 and the workpiece W becomes zero by the cutting drive unit 60. The detection of zero backlash can be performed based on the torque control function. The backlash state is not uniform in the direction in which the teeth are arranged due to the processing accuracy of the rotating grindstone 51 and the workpiece W, distortion due to heat treatment, attachment error to the jig, and the like. On the other hand, for example, the following means can be applied. The feed torque in the z-axis direction by the horizontal drive motor 61 is kept constant, and the previous and current z-axis coordinate values are changed every scan (one round of processing from the beginning to the end of the feed control program in the programmable controller) by the programmable controller. Compare. When the difference becomes a small value that can be regarded as zero or substantially zero, the backlash is zero. Alternatively, the position of the rotating grindstone in the z-axis direction in which the workpiece and the rotating grindstone are meshed in advance in the manual mode and zero backlash is detected, and the rotating grindstone 51 is advanced to the position set by the detection data. (FIG. 7G) (step 12).
[0041]
When the backlash is zero, the rotary grindstone 51 stops immediately. At this time, since the main shaft 32 is torque limited, the workpiece W is being rotated around the rotating grindstone 51. Therefore, there is a deviation from the electrical synchronization and phase matching position set in step 6. This phase shift is detected, the drive phase is corrected so as to eliminate it, and the drive phase of each control motor is fixed. In this way, the position where the backlash between the rotating grindstone 51 and the workpiece W becomes zero is officially recognized by the programmable controller or the like as the synchronization and phase matching position of the master (rotating grindstone) and slave (work axis) (step) 13). For the above-described phase shift, instead of correcting the drive phase so as to eliminate the phase shift as described above, it is also possible to newly determine the drive phase so as to cancel the drive phase.
[0042]
In the following, grinding will be started, but this method has a plurality of selectable forms as described below.
[0043]
At the same time as the rotary grindstone 51 is advanced by plunge feed (the head is advanced while the table is fixed), the restriction on the output torque of the work drive motor 33 is gradually released. At this time, the torque of the work drive motor 33 and the feed speed of the rotating grindstone 51 are controlled so that no electrical phase shift occurs (step 14).
[0044]
Instead of the step 14, the output torque limit of the work drive motor 33 is canceled and the constant torque cutting can be performed to the maximum value set (step 14A).
[0045]
After that, the table 10 is reciprocated in the main axis direction (left and right direction in FIG. 4) to perform grinding. For this purpose, every time the table switches the moving direction, cutting is performed (Z-axis). If the workpiece W is a helical gear, grinding is performed while performing helical correction (step 15).
[0046]
When step 14A is employed, instead of step 15, the current of the work drive motor 33 is detected and the feed speed of the rotating grindstone 51 by the horizontal drive motor 61 is automatically adjusted so that grinding can be performed with a constant torque. The parallel feed is then performed (step 15A).
[0047]
During parallel feeding, the crowning shaft (B-axis) is driven to perform crowning. The parallel feed is performed while gradually increasing the moving distance from the center of reciprocation of the table (X axis). Further, every time the table (X-axis) switches the direction, the horizontal drive motor 61 moves forward (Z-axis). Then, machining is performed until reaching the set position of the cutting axis (z axis) corresponding to the final shape of the workpiece (step 16).
[0048]
When reaching the set position, in order to grind the flank on the opposite side of the tooth of the workpiece W, the synchronization phase is shifted in the opposite direction to the previous direction. The amount of phase shift is determined by a program (step 17).
[0049]
When finishing the flank on both sides, it is desirable to perform final finishing. This can be done by restricting the torque of the work drive motor 33 again, turning the spindle around, performing table feed and crowning without cutting (step 18).
[0050]
Next, the rotary grindstone 51 is moved backward from the work W, and then the work drive motor 33 is stopped by releasing the synchronization. Further, the table 10, the rotating grindstone 51, each of the crowning axes (X axis, Z axis, B axis) and the work drive motor 33 are returned to the origin. As a result, the machining of one workpiece W is completed, and the next workpiece is ready for machining (step 19).
[0051]
In step 9, the control motor of the main shaft 32 is adjusted to adjust the phase. Alternatively, the phase adjustment can be performed by the control motor of the rotating grindstone 51.
[0052]
Further, although the torque of the control motor of the main shaft 32 is limited in steps 11 to 13 and the limitation is released in steps 14 and 14A, the torque limitation and the release of the control motor of the rotating grindstone 51 are replaced instead. You can also do it.
[0053]
II. When performing manual operation from workpiece replacement to the start of synchronous drive of the spindle and forming tool
Hereinafter, description will be made with reference to the main part explanatory view of FIG. 9 and the flowchart of FIG. In this case, the workpiece W and the rotating grindstone 51 are manually meshed with a slight backlash. The amount of this backlash is set to a slight gap so that no biting occurs when driving rotation is started after manual meshing, for example, 0.01 mm or slightly smaller than this (see FIGS. 9A ′ to 9A ′). C ′) (Step 1B).
[0054]
In this state, the workpiece W is clamped by the main shaft 32 and the tailstock shaft 42. As a result, the workpiece W is placed in a state in which the phase substantially coincides with the rotating grindstone 51 and is held in a clamped state by the main shaft 32 and the tailstock shaft 42. Here, since the operation is performed with the rotating grindstone 51 and the main shaft 32 stopped, the engagement with a slight backlash is kept so as not to hinder the subsequent driving rotation (step 2B).
[0055]
Next, the drive torque of the control motor 33 coupled to the main shaft 32 is reduced to such an extent that cutting by the rotating grindstone 51 does not occur. In this state, the main shaft and the forming tool are synchronously rotated under the control of each control motor. Thereby, the main shaft 32 is rotated along with the rotating grindstone 51 (step 3B).
[0056]
In this state, the main shaft 32 and the rotating grindstone 51 are brought close to a position preset as zero backlash or a detected position. In this state, the torque of the control motor 33 of the main shaft 32 is driven although it is low, so that both control motors are in phase close to the target synchronous drive (FIG. 9D ′). (Step 4B). For the synchronization error, a new drive phase can be set to eliminate the synchronization error instead of correcting the error as described above.
[0057]
Here, the synchronization error of each control motor of the spindle 32 and the rotating grindstone 51 at the position of zero backlash is detected, and after correction, the drive phase is fixed. As a result, synchronous driving with exactly the same phase is possible (step 5B). The drive phase before correction is determined by returning the control motor to the rotation direction origin after completion of finishing of each workpiece or before starting of machining. For the synchronization error, a new drive phase can be set to eliminate the synchronization error instead of correcting the error as described above.
[0058]
Thereafter, as in the case of I., the torque limitation of the control motor 33 of the main shaft is released, and cutting is performed by gradually increasing the cutting amount. The process corresponds to steps 14 and 14A to 19 of I. above.
[0059]
In Step 3B, the torque of the control motor 33 of the main shaft 32 is limited, and the limitation is canceled in Steps 14 and 14A. Instead, torque limitation and cancellation of the control motor of the rotating grindstone 51 are performed. You can also do it.
[0060]
【The invention's effect】
In the present invention, in the first invention, the spindle for supporting the workpiece and the forming tool are driven by servo control by a servo motor or Cs control by an AC spindle motor, and the phase is determined by the control (primary phase determination). ). Further, phase correction is performed by the workpiece positioning device, and the reference position is adjusted by reading the phase shift by setting the control motor in a free-run state (secondary phase determination). In addition, with the drive torque of the spindle lowered, the backlash is zero and the phase shift between the control motors of the spindle and the forming tool is detected and eliminated, and then the drive phase is fixed. Yes (tertiary phase determination). In this way, the phase of the workpiece and the forming tool can be matched exactly. In this state, if cutting is performed by gradually increasing the cutting depth, finish cutting with extremely high accuracy by synchronous driving can be performed. The above operation can be performed without stopping the rotation of the forming tool once the forming tool has been phased. According to this method, the phase adjustment after the workpiece W is attached to the main shaft can be performed by the workpiece positioning device, which is advantageous in automating the operation.
[0061]
In the present invention, in the second invention, the work and the forming tool are manually engaged with backlash attached, and the work is clamped by the main shaft and the tailstock shaft. As a result, the workpiece is placed in a state in which the phase is substantially matched to the forming tool. Further, in a state where the driving torque of the control motor coupled to the main shaft or the forming tool is lowered, the main shaft and the forming tool are rotated synchronously by the respective control motors, and the main shaft and the forming tool are brought close to the position of zero backlash. As a result, a follow-up state is formed, and one of the control motors is driven with a low torque, so that both control motors are exactly in phase with each other in a state close to the intended synchronous drive. Then, the phase shift between the control motors of the spindle and the forming tool is detected and eliminated, and then the drive phase is fixed. In this state, if each control motor is driven with a torque required for cutting and the spindle and the forming tool are rotated synchronously and the cutting amount is gradually increased to perform cutting, the highly accurate finish cutting by synchronous driving can be performed. . In this method, the process of meshing the work and the forming tool with backlash is manual, but the initial phasing can be performed in a short time, and the entire operation time for synchronous drive can be shortened. The advantage is obtained.
[Brief description of the drawings]
FIG. 1 is a front view of a gear finishing device according to a primary embodiment of the present invention.
FIG. 2 is a side view of the gear finishing apparatus shown in FIG.
FIG. 3 is a plan view of the gear finishing apparatus shown in FIG.
FIG. 4 is a front view mainly showing an operation part of the gear finishing device shown in FIG. 1;
FIG. 5 is a front view mainly showing a work support state of the gear finishing device shown in FIG. 1;
6 is a perspective view showing a use state of the workpiece positioning device in the gear finishing device shown in FIG. 1. FIG.
7 is an explanatory view showing an operation state according to the first invention by the gear finishing apparatus shown in FIG. 1; FIG.
8A is a flowchart showing an operation procedure of the operation shown in FIG.
FIG. 8B is a flowchart following FIG. 8A.
FIG. 9 is an explanatory view showing an operation state according to the second aspect of the gear finishing apparatus shown in FIG. 1;
10 is a flowchart showing an operation procedure of the operation shown in FIG.
[Explanation of symbols]
10 tables, 20 holding devices,
30 headstock, 31 headstock body,
32 spindles, 33 work drive motors,
41 Tailstock body, 42 Work support shaft,
50 grinding wheel holding device, 51 rotating grinding wheel,
53 holding part, 531 head drive motor,
60 cutting drive unit, 80 workpiece positioning device,
W Work

Claims (4)

A gear finishing method for driving a workpiece supporting spindle supported by a machine base and a finishing molding tool to rotate synchronously when forming and finishing a gear as a workpiece,
The main shaft and the forming tool are driven by a control motor by servo control by a servo motor or Cs control by an AC spindle motor.
The gear finishing method is:
The movement of the control motor to the rotation direction origin and the attachment of the work to the main shaft and the tailstock shaft in a state where the tailstock shaft is not rotated and clamped;
Engaging the workpiece positioning device with the workpiece to position the workpiece in the rotational direction;
A step of rotating the tailstock shaft in a rotational clamp state in a state where the workpiece is engaged with the workpiece positioning device;
Bringing the control motor coupled to the spindle into a free-running state;
A step of reading a phase shift with respect to the main shaft side of the control motor side in the main shaft generated in accordance with a free-run state;
Removing the workpiece positioning device from the workpiece;
Correcting one drive phase of a control motor coupled to the main shaft and a control motor coupled to the forming tool to eliminate the phase shift, synchronizing the main shaft and the forming tool with each control motor; and Rotating in phase with each other;
Bringing the spindle and the forming tool close to the extent that the workpiece and the tip circle of the forming tool cross each other;
One of the control motor coupled to the spindle and the control motor coupled to the forming tool is preset as zero backlash in a state where the drive torque of the control motor is reduced to such an extent that cutting by the forming tool does not occur. Bringing the spindle and the forming tool closer to a detected position or a detected position;
Detecting a phase shift between the control motors of the spindle and the forming tool at the position of zero backlash, and fixing the drive phase of the control motors;
A gear finishing method comprising: driving each control motor with a torque required for cutting, and performing a finish cutting by gradually increasing a cutting amount while synchronously rotating the main shaft and the forming tool. Wherein the step of performing finishing machining, gear finishing method according to claim 1, characterized in that performing while titrated to normal driving torque of the one control motor. The step of performing the finishing cutting, the gear finishing method according to claim 1, characterized in that performing while adjusting the detected notch speed drive load current value of the servo motor or AC spindle motor of said forming tool or spindle . A gear finishing method for driving a workpiece supporting spindle supported by a machine base and a finishing molding tool to rotate synchronously when forming and finishing a gear as a workpiece,
The main shaft and the forming tool are driven by a control motor by servo control by a servo motor or Cs control by an AC spindle motor.
The gear finishing method is:
Manually engaging the workpiece and the forming tool with a slight backlash, and clamping the workpiece with the spindle and the tailstock;
With the drive torque of one of the control motor coupled to the main shaft and the control motor coupled to the forming tool reduced to such an extent that cutting by the forming tool does not occur, the main shaft and the forming tool are connected to each control motor. A step of synchronously rotating by control;
Bringing the spindle and the forming tool closer to a position preset or detected as backlash zero;
Detecting a synchronization error of each control motor of the main shaft and the forming tool at the position of zero backlash, eliminating the synchronization error, and fixing the drive phase;
A step of driving each control motor with a torque required for cutting and performing a finish cutting by gradually increasing a cutting amount while synchronously rotating the spindle and the forming tool,
In the step of performing the finish cutting, the restriction on the driving torque that has been lowered to the extent that cutting does not occur is released, the torque is returned to the set maximum value, and then the cutting is performed with a constant torque. A gear finishing machining method, which is carried out while detecting the drive load current value of the forming tool or the servo motor of the spindle or the AC spindle motor and adjusting the cutting speed.

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