JP4635142B2 - Gear finishing device and gear meshing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gear meshing method for synchronously rotationally driving a gear to be ground and a finishing forming tool , and a gear finishing apparatus based on the method .
[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 zero backlash state, both are driven and rotated synchronously. For example, in the machining 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 backlash is reduced to zero. The position correction amount of the forming tool necessary for this is obtained, and the feed tool is fed to the forming tool based on the position correction amount to achieve synchronization.
[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. Further, in the conventional method, it is necessary to stop the forming tool every time the grinding of the gear to be ground is finished, and to start driving the shaping tool again after the new gear to be ground is mounted. Therefore, the driving and stopping of the heavy forming tool are repeated, and there is a problem that the time efficiency of processing is poor and time-consuming.
[0007]
[Problems to be solved by the invention]
The present invention eliminates the need to stop the forming tool every time the gear to be ground is ground when performing gear finishing by synchronous rotation, and repeats the minute rotation of the forming tool which is troublesome even when stopped. It is an object of the present invention to provide a gear meshing method capable of starting continuous rotation of a gear to be ground and a forming tool without need, and a gear finishing apparatus based on the method .
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a gear meshing method for synchronously rotating and driving a work support shaft and a finishing forming tool supported by a machine base when forming and finishing a gear as a work. The workpiece support shaft and the forming tool are driven by respective control motors, and the work support shaft and the forming tool are brought close to a position of zero backlash in a state where the driving torque of the workpiece support shaft is limited, The drive phase of each control motor of the workpiece support shaft and the forming tool at the position of zero backlash is reset as a phase coincidence point, the restriction on the drive torque of the workpiece support shaft is released, and the drive of each control motor A gear meshing method is provided, wherein the workpiece support shaft and the forming tool are rotated synchronously .
[0009]
In order to achieve the above object, the present invention is also a gear finishing device for forming and finishing a gear while synchronously rotating a work support shaft and a finishing forming tool, and each of the work support shaft and the forming tool. A control motor which is provided and can drive these synchronously, a control device which controls the work support shaft, the finishing forming tool and the control motor, and the work support after reaching the position where the finishing forming tool and the gear mesh with each other. Drive torque limiting means for limiting the drive torque of the shaft control motor, zero backlash detection means for detecting that the meshing between the finishing forming tool and the gear is in a zero backlash state, and the backlash The drive phase resetting is performed by resetting the drive phase of each control motor of the workpiece support shaft and the forming tool at the zero position as a phase matching point. There is provided a gear finishing apparatus characterized by comprising a constant section.
[0010]
[Action]
In the gear meshing method according to the present invention, in grinding and finishing the gear as a workpiece, the workpiece support shaft and the forming tool are driven by the respective control motors, and the drive torque of the workpiece support shaft is limited. The work support shaft and the forming tool are brought close to the backlash zero position. Since the work support shaft has a limited driving torque, the workpiece supporting shaft is rotated with respect to the forming tool by contact with the forming tool while receiving the limited driving force. Then, the drive phase of each control motor of the workpiece support shaft and the forming tool at the position of zero backlash is reset as a phase matching point. Thereby, it fixes in the state in which the drive phase of each control motor of a workpiece | work support axis | shaft and a forming tool matched correctly. Thereafter, the restriction on the drive torque of the workpiece support shaft is released, and the workpiece support shaft and the forming tool are rotated synchronously by driving each control motor. As a result, the workpiece support shaft and the forming tool are synchronously driven with the drive phases accurately matched.
[0011]
In this state, if cutting is performed while gradually increasing the depth of cut, it is possible to perform finish cutting with extremely high accuracy by synchronous drive.
[0012]
A gear finishing apparatus according to the present invention includes a control motor that is provided for each of a work support shaft and a forming tool, and that can synchronously drive them, a control device for the work support shaft, a finishing forming tool and a control motor, and a work support Drive torque limiting means for limiting the drive torque of the shaft control motor, zero backlash detection means for detecting that the engagement is in a zero backlash state, the workpiece support shaft at the zero backlash position, Since there is a drive phase resetting means for resetting the drive phase of each control motor with the forming tool as a phase matching point, the above-described meshing method is carried out so that the workpiece support shaft and the forming tool are moved to the drive phase. Can be synchronously driven in a state where the values exactly match.
[0013]
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.
[0014]
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 two headstocks 30 and tailstocks 40 that are slidable on the table so as to approach and separate from each other and each have a work support shaft. A grindstone holding device 50 is further mounted on the machine base B.
[0015]
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 includes a tailstock body 31 supported by the table 10, a work support shaft 32 rotatably supported by the tailstock body, and a tailstock. A drive motor 33 that is coupled to the base body 31 and rotates the work support shaft 32 is provided. The other (right in the figure) tailstock 40 includes a tailstock body 41 supported by the table 10 and a work support shaft 42 rotatably supported by the tailstock body.
[0016]
As shown in FIG. 5, the workpiece support shaft 42 is provided with a clamping shaft 43 which advances retract axially within the shaft by the drive unit outside the drawing attached to the tailstock body 41. Therefore, the workpiece W can be clamped in the rotational direction on the workpiece support shaft by supporting the workpiece W by the workpiece support shafts 32 and 42 with the clamp shaft 43 retracted and then moving the clamp shaft 43 forward. . In this example, the work drive motor 33 is a servo motor so as to enable the control described below.
[0017]
As shown in the drawing, the grindstone holding device 50 is located between the head stock 30 and the tailstock 40 and has a ring-shaped head 52 that supports the rotating grindstone 51, and the head 52 is attached to the work support shafts 32 and 42. And a holding portion 53 that is rotatably supported around a vertical horizontal axis. As shown in FIGS. 2 and 3, the holding unit 53 includes a head drive motor 531 for rotating the head 52 around the work support shaft, and a horizontal axis line perpendicular to the work support shafts 32 and 42. A head tilt motor 532 is provided for rotation. 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 can move along a horizontal axis perpendicular to the workpiece support shafts 32 and 42 by driving of a horizontal drive motor 61, and the head 52 and the rotating grindstone 51 approach the workpiece on the workpiece support shaft by the movement. Separate them and make a cut when grinding.
[0018]
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.
[0019]
A work 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 work support 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.
[0020]
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.
[0021]
Next, a more detailed configuration of the gear finishing device will be described together with the operation procedure of the device shown in the flowchart of FIG .
[0022]
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 workpiece on the workpiece support shaft in the manual mode, and the meshing of the rotating grindstone is made uniform throughout the entire circumference of the workpiece. Set the phase origin.
[0023]
When you are this preparation, by a workpiece drive motor 33 of the headstock 30 in the state of being returned to the origin of the encoder, the workpiece drive motor 33 to the servo lock state. Before or after this operation, the workpiece W is mounted on the workpiece support shaft. (Step 1)
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 work support shafts 32 and 42. Here, the clamp shaft 43 of the workpiece support shaft 42 is in the retracted position. (Step 2)
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 workpiece support shaft 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)
The clamp shaft 43 of the workpiece support shaft 42 is advanced while maintaining the meshed state with the projection 85, and the workpiece W is fixed on the workpiece support shafts 32 and 42 in the rotation direction. (Step 4)
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 work support shaft 32 is in a free-run state without any restriction in the rotation direction. As described above, even if the work drive motor 33 is in the origin return state, the phase of the work W on the work support shaft 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 work support shaft 32 by the work drive motor 33 and the support portion of the work W. Therefore, the work support motor 32 is returned to the torsional deformation at the place supported by the work drive motor 33 by setting the work drive motor 33 in the free run state while maintaining the meshed state of the work W and the work positioning device 80. Rotate slightly. (Step 5)
A slight correction rotation amount of the work support shaft 32 generated by setting the work drive motor 33 to the 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)
From this state, the workpiece positioning device 80 is retracted away from the workpiece W. (FIG. 7C) (Step 7)
After the workpiece positioning device 80 moves backward, the workpiece and the rotating grindstone are engaged. First, the work drive motor 33 is operated to rotate the work support shafts 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)
While the workpiece W approaches the center of the rotating grindstone 51, the workpiece support shaft 32 is synchronized and phased. That is, it is detected by the encoder coupled to the work support shaft 32 and the head 52 that the work support shaft 32 has reached the synchronous speed with respect to the rotary grindstone 51, and then based on the origin corrected in the above-mentioned step 5. Perform phase alignment. In parallel with this, the cutting drive unit 60 is actuated to advance the rotating grindstone 51 toward the workpiece W side (z-axis direction). (FIG. 7E) (Step 9)
After completion of the synchronization phase alignment, the rotary grindstone 51 is further advanced to a position where the both ends of the rotating grindstone 51 and the workpiece W are slightly engaged. At this time, it is desirable to use cutting feed instead of rapid feed in order to prevent tooth damage due to collision. (FIG. 7F) (Step 10)
After reaching the position where the tips of both teeth of the rotating grindstone 51 and the workpiece W are sufficiently engaged with each other, the output torque of the workpiece driving motor 33 is lowered to an extent where cutting is impossible. (Step 11)
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. Also good. (FIG. 7G) (Step 12)
When the backlash is zero, the rotary grindstone 51 stops immediately. At this time, since the workpiece support shaft 32 limits the torque, the workpiece W is being rotated with respect to the rotating grindstone 51. Therefore, there is a deviation from the electrical synchronization and phase matching position set in step 6. The position where the backlash between the rotating grindstone 51 and the workpiece W becomes zero is formally recognized by the programmable controller or the like as the synchronization and phase matching position of the master (rotating grindstone) and slave (workpiece axis). (Step 13)
In the following, grinding will be started, but this method has a plurality of selectable forms as described below.
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)
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)
Thereafter, the table 10 is reciprocated in the workpiece support 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). When the workpiece W is a helical gear, grinding is performed while performing helical correction. (Step 15)
When step 14A is used, instead of step 15, the current of the work drive motor 33 is detected so that grinding can be performed with a constant torque, and the feed speed of the rotating grindstone 51 by the horizontal drive motor 61 is automatically set. Perform parallel feed while adjusting. (Step 15A)
During parallel feeding, the crowning shaft (B-axis) is driven to perform crowning. The parallel feeding is performed while gradually increasing the moving distance from the center in the reciprocating motion of the table (X axis). Further, every time the table (X-axis) switches the direction, the horizontal drive motor 61 moves forward (Z-axis). And it processes until it reaches the setting position of the cutting axis (z-axis) corresponding to the final shape of the workpiece. (Step 16)
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 the program. (Step 17)
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 work support shaft around, performing table feed and crowning without cutting. (Step 18)
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)
[0024]
【The invention's effect】
In the gear meshing method according to the present invention, when forming and finishing a gear as a work, the work support shaft and the forming tool are driven by the respective control motors, and the driving torque of the work support shaft is limited. The work support shaft and the forming tool are brought close to the position of zero backlash, the drive phase of each control motor of the work support shaft and forming tool at the zero backlash position is reset as the phase match point, and the work support shaft The restriction on the driving torque is released, and the workpiece support shaft and the forming tool are rotated synchronously by driving each control motor. Therefore, the work support shaft is once limited in driving torque and is rotated with respect to the forming tool. When the work support shaft reaches the position of zero backlash in this state, the control motors of the work support shaft and the forming tool are driven. Reset phase as phase match point. As a result, the drive phases of the control motors of the workpiece support shaft and the forming tool are fixed in a state where they are precisely matched, and then the restriction on the drive torque of the workpiece support shaft is released, and the workpiece support is supported by driving of each control motor Synchronously rotate the shaft and forming tool. As a result, the workpiece support shaft and the forming tool are synchronously driven with the drive phases accurately matched. Therefore, when performing gear finishing by synchronous rotation, it is not necessary to stop the forming tool every time the gear to be ground is ground, and it is necessary to repeat the minute rotation of the forming tool which is troublesome even if it is stopped. The continuous rotation of the gear to be ground and the forming tool can be started without doing so.
[0025]
A gear finishing apparatus according to the present invention includes a control motor that is provided for each of a work support shaft and a forming tool, and that can synchronously drive them, a control device for the work support shaft, a finishing forming tool and a control motor, and a work support Drive torque limiting means for limiting the drive torque of the shaft control motor, zero backlash detection means for detecting that the engagement is in a zero backlash state, the workpiece support shaft at the zero backlash position, Drive phase resetting means that resets the drive phase of each control motor with the forming tool as a phase matching point is provided, so that the above-mentioned meshing method is carried out to finish the gear by continuous rotation of the forming tool. Can be done.
[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;
5 is a front view centering on a workpiece support state of the gear finishing device shown in FIG. 1. FIG. 6 is a perspective view showing a use state of the workpiece positioning device in the gear finishing device shown in FIG.
FIG. 7 is an explanatory view showing a processed body by the gear finishing device shown in FIG. 1;
8A is a flowchart showing an operation procedure in a workpiece support state of the gear finishing device shown in FIG. 1. FIG.
FIG. 8B is a flowchart following FIG. 8A.
[Explanation of symbols]
10 table 10, 20 holding device,
30, 40 Tailstock, 31 Tailstock body,
32 workpiece support shaft, 33 workpiece drive motor,
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 (2)

A gear meshing method for synchronously rotating and driving a work support shaft supported by a machine base and a finishing forming tool in forming and finishing a gear as a work,
The workpiece support shaft and the forming tool are synchronously driven by each control motor, and the drive phase is adjusted,
Bringing the work support shaft and the forming tool closer to a position where the work and the forming tool are engaged,
Lowering and limiting the drive torque of the workpiece support shaft ,
Bring the workpiece support shaft and the forming tool close to the zero backlash position,
Resetting the drive phase of each control motor of the workpiece support shaft and the forming tool at the position of zero backlash as a phase matching point,
Release the drive torque limit of the workpiece support shaft,
A gear meshing method, wherein the workpiece support shaft and the forming tool are synchronously rotated by driving each control motor in the state of the reset driving phase . A gear finishing device for forming and finishing a gear while synchronously rotating a workpiece support shaft and a finishing forming tool,
A control motor provided for each of the workpiece support shaft and the forming tool and capable of synchronously driving them;
A control device for controlling the workpiece support shaft, the finishing forming tool and the control motor;
Drive torque limiting means for lowering and limiting the drive torque of the work support shaft control motor after reaching the position where the finish forming tool and the gear mesh with each other;
Zero backlash detection means for detecting that the meshing between the finishing forming tool and the gear is in a zero backlash state;
A gear finishing device comprising: drive phase resetting means for resetting a drive phase of each control motor of the workpiece support shaft and the forming tool at a position of zero backlash as a phase matching point.

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