JPH09174330A - Automatic meshing device in gear grinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable positions of both tooth surface of tooth part to be respectively detected accurately without grinding those surfaces by providing a servo-error detecting means for detecting servo error as the result of giving a position offset instruction in both normal and reverse directions in such a state as a position loop gain is switched to a low value. SOLUTION: A calculation circuit 41 of 2 phase type PLL compensates an analog voltage corresponding to a pulse from a pulse generating circuit 40 so that the servo-error (to be detected, concerning a rotational angle position of a main shaft 16, by calculating a difference between a command position inputted from a numerical value controller 30 and a detected value inputted from an encoder 18a) may be corrected to become zero. In addition, it is also corrected and outputted in response to the offset instruction of the rotational angle position of the main shaft 16 inputted from the numerical value controller 30. This position offset instruction is to guide a gear W to make its offset in normal or reverse rotational direction by a specified minute quantity one by one.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear grinding apparatus using a screw-shaped grindstone, and relates to an automatic tooth-matching device for automatically performing tooth-matching between the screw-shaped grindstone and a gear prior to grinding.

[0002]

2. Description of the Related Art In a gear grinding machine of this type, it is necessary to carry out a highly accurate tooth engagement between a screw-shaped grindstone and a gear prior to grinding. There is a problem that uneven grinding, which is unground or incomplete grinding, occurs, and the load of the grindstone becomes excessive, so that the life of the grindstone is shortened. As an automatic tooth aligning device for solving such a problem, for example, there is a technique disclosed in Japanese Patent Publication No. 62-38089. This is because the gear is manually engaged with the screw-shaped grindstone with the electromagnetic clutch provided in the rotary drive path that rotates the main shaft that grips the gear via the clamp jig released, and then the screw-shaped grindstone is rotated at low speed. After performing the initial phase alignment based on the output from the work sensor that detects the tooth portion and the pulse from the pulse generator provided on the grindstone shaft, the grindstone is temporarily retracted, and the electromagnetic clutch is engaged to shift the gear and The screw-shaped grindstone is rotationally driven, the phase shift between the gear and the screw-shaped grindstone is corrected based on the data obtained in the initial phase adjustment, and the grindstone is advanced to perform grinding.

Further, the position of each tooth of the gear rotating with the main shaft is detected by a proximity sensor arranged in the radial direction or the axial direction, and the gears and the thread grindstone are aligned with each other in the rotating state of the main shaft. There is also.

[0004]

However, in the technique disclosed in Japanese Patent Publication No. 62-38089, the thread portion of the threaded grindstone is surely equally secured to the tooth flanks on both sides of the tooth portion of the gear in the initial phase alignment state. Since contact is not guaranteed, it is not always possible to achieve sufficient tooth engagement between the threaded wheel and the gear prior to grinding. Further, even in the technique of detecting the position of each tooth portion by the proximity sensor, the detection error is, for example, about several tens of microns on the tooth surface, and thus sufficient matching accuracy cannot be obtained. An object of the present invention is to solve each of the problems described above, and to enable automatic engagement with high precision between the thread-shaped grindstone and the gear prior to grinding.

[0005]

DISCLOSURE OF THE INVENTION The present invention is directed to a gear side servo drive device for rotating a main shaft that connects gears and rotates integrally with the gear, and a grindstone for rotationally driving a grindstone shaft provided with a screw-shaped grindstone. Side servo drive device and the position in the rotational direction of the spindle and the grindstone shaft so that the inclined grinding surface of the thread portion of the threaded grindstone grinds the tooth surface of the gear tooth portion by giving a command to both servo drive devices. The present invention relates to a gear grinding device equipped with a control device that controls the position of the servo system, and selectively selects the position loop gain of at least one of the servo drive devices to a high value suitable for grinding and a value significantly lower than that. A gain adjusting means for switching to is provided. With this position loop gain adjusting device, the position loop gain is switched to a low value, and the notch means causes the thread portion to enter between the tooth portions, but the position offset command means in a state in which the notch does not contact the two. Gives a position offset command to both at least one of the servo drive devices in the forward and reverse rotation directions such that the distance between the ground surface of the thread portion and the tooth surface of the tooth portion gradually decreases. Since the position loop gain has been switched to a low value, the former does not grind the latter even if the threaded surface of the thread and the tooth surface of the tooth contact each other, and the servo error detection means uses a low position loop gain. The servo error which is the difference between the command value given the position offset by the position offset command means and the detected value which is the actual position of the position of the spindle or the grindstone shaft corresponding to the servo drive device switched to Detect in the direction of rotation. The meshing position calculating means calculates the optimum meshing position based on the servo errors in both the forward and reverse directions detected in this way, and the meshing position correcting means calculates the meshing position based on the optimum meshing position. Make a correction.

It is preferable that the gain adjusting means of the present invention selectively switches the position loop gain of the servo system of the gear side servo drive device between a high value suitable for grinding and a value significantly lower than that. .

According to the present invention, in a state where the thread-shaped grindstone and the gear do not mesh with each other in the traverse direction substantially parallel to the axial direction of the latter, the position-offset command means gives a position-offset command and then the thread-shaped grindstone is moved. It is preferable to move the gear in the traverse direction and detect the servo error by the servo error detecting means.

According to the present invention, the initial tooth aligning means for detecting the tooth portion of the gear with the proximity sensor to calculate the initial tooth aligning position at which the thread portion of the thread-like grindstone approximately coincides with the intermediate position of the tooth portion of the gear. It is preferable that the cutting means provides the cutting at the initial meshing position.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS. As shown in FIG. 1, an X-axis slide table 11 guided and supported on a bed 10 of a gear grinding device so as to be movable in the horizontal X direction (a direction perpendicular to the paper surface) is fed by the first drive motor 13 in the X direction. The Z-axis slide table 12, which is provided and guided and supported on the X-axis slide table 11 so as to be movable in the horizontal Z direction orthogonal to the X direction, is fed by the second drive motor 14 in the Z direction. On the Z-axis slide table 12, a headstock 15 supporting a main shaft 16 and a tailstock 17 are coaxially provided so as to face each other in the Z direction, and one end of a gear W having shafts formed on both sides is not shown. It is coaxially gripped by the main shaft 16 via the chuck and the other end is rotatably supported by the tailstock 17. The spindle 16 is rotationally driven by a spindle rotation driving motor 18 provided on the spindle stock 15, and the gear W is the spindle 1.
6 and 6 are integrally rotated. Each motor 13,1
Reference numerals 4 and 18 respectively include encoders 13a, 14a and 18a for detecting the position of the driven table or shaft.

In addition, an X-direction axis A perpendicular to the axis of rotation of the main shaft 16 is provided on the column 20 that integrally stands up from the bed 10.
A Y-axis slide table 22 is guided and supported by a swivel base 21 which is rotatably supported around the Y-axis so as to be movable in a Y direction orthogonal to the axis A, and is fed by a third drive motor 23. . The whetstone base 25 fixed on the Y-axis slide table 22 is provided with a whetstone shaft 26 having a rotation axis parallel to the Y direction and coaxially fixing a threaded grindstone G at the tip thereof. It is driven to rotate by the grindstone shaft rotation driving motor 28. The thread portion Ga having a rack-shaped cross-section formed on the threaded grindstone G has inclined grinding surfaces Gb and Gc for grinding the tooth surfaces Wb and Wc of the tooth portion Wa of the gear W.
(See FIGS. 5 and 8). The swivel base 21 is rotationally driven around the axis A by a drive motor (not shown), so that the tangential direction of the portion of the helical screw thread Ga that contacts the tooth portion Wa coincides with the tooth trace direction of the gear W. It is turned and stopped and locked. Each motor 23, 28
Are provided with encoders 23a and 28a for detecting the position of the driven table or shaft, respectively.

As shown in FIG. 1, the numerical control device 30 includes:
Central processing unit (CP that controls and manages the entire gear grinding device
U) 31, a memory 32, and an interface I / F for exchanging data with the outside. The CPU 31
A feed position command is given to the first and second drive circuits 35 and 36 via the interface I / F to drive the first and second drive motors 13 and 14, whereby the X-axis and Z-axis slide tables 11, Feed 12 and encoder 1
3a and 14a detect the feed positions of the slide tables 11 and 12 via the rotation angles of the drive motors 13 and 14, and the detected values are sent to the CPU 31 via the interface.
Is input to

Further, the CPU 31 has an interface I /
A rotation angle position command is given to the spindle and grindstone shaft drive circuits 37 and 38 via F to drive the spindle and grindstone shaft rotation drive motor 1.
8 and 28 are driven, whereby the main shaft 16 and the grindstone shaft 26 are driven.
The encoders 18a and 28a detect the rotation angle positions of the spindle 16 and the grindstone shaft 26 via the rotation angles of the drive motors 18 and 28, and the detected values are input to the CPU 31 via the interface. It Although illustration is omitted, the third drive motor 23 is similarly driven by the CPU 31 via a drive circuit to drive the Y-axis slide table 2
2 is fed, and the detected value of the feed position detected by the encoder 23a is input to the CPU 31.

The CPU 31 has an interface I / F.
Although not shown in the drawing, the input / output device 33 is connected via a linear proximity sensor S of the eddy current type or the like, which is arranged in the radial direction with respect to the tooth portion Wa of the rotating gear W.
(See FIG. 5) are connected via an interface. The CPU 31 controls each component based on the input from the input / output device 33 and the detectors such as the proximity sensor S and each encoder to perform a series of operations described later. A control program for performing the above, a grinding process program for the gear W, various data, and the like are stored.

The spindle drive circuit 37, as shown in FIG.
Pulse generation circuit 40, arithmetic circuit 41, servo controller 42, gain controller 43, and servo amplifier 44
It is composed of The pulse generation circuit 40 generates a pulse according to the rotation angle position command value input from the numerical control device 30 every moment. The arithmetic circuit 41 is a two-phase type PLL.
(Phase Locked Loop) is used, and an analog voltage corresponding to the pulse from the pulse generation circuit 40 is input from the servo error (command value input from the numerical control device 30 regarding the rotation angle position of the spindle 16 and the encoder 18a). Detected by calculating the difference between the detected values to be zero, and the spindle 1 input from the numerical control device 30.
It is corrected and output according to the offset command of the rotational angle position of No. 6. This position offset command is applied to the gear W
Is offset by a predetermined minute amount (positional offset amount) in the forward or reverse rotation direction. The arithmetic circuit 4
Although 1 uses the two-phase PPL in the above, a general servo error calculation circuit such as a pulse counter may be used.

The output voltage from the arithmetic circuit 41 is converted into a current by a servo amplifier 44 via a servo controller 42 and a gain controller 43, and this current is given to a spindle rotation driving motor 18 to rotate the spindle 16. The servo controller 42 is, for example, an arithmetic circuit that performs proportional, differential, and integral arithmetic operations on the output voltage from the arithmetic circuit 41, and the gain controller 43 is an amplifier circuit that increases or decreases the output voltage from the servo controller 42.
The gain is a high value suitable for grinding the tooth surfaces Wb and Wc of the gear W (corresponding to large servo rigidity) and a value significantly lower (corresponding to smaller servo rigidity) according to a gain command from the numerical controller 30. Can be selectively switched to two stages. The gain can be set to any value. The servo error detected by the arithmetic circuit 41 is also input to the numerical controller 30.

The structure of the grindstone shaft drive circuit 38 is similar to that of the main shaft drive circuit 37, except that there is no gain controller 43 and there is no position offset command or gain command from the numerical controller 30. The first and second drive circuits 35 and 36 have substantially the same configuration as the grindstone shaft drive circuit 38.

In the relationship between the present embodiment and each claim, the spindle drive circuit 37, the spindle rotation drive motor 18 and the encoder 18a constitute a gear side servo drive device, the grindstone spindle drive circuit 38, the grindstone spindle rotation drive motor 28. And encoder 28
a is a whetstone side servo drive device, and a gain controller 43
And a part of the numerical control device 30 is provided with a gain adjusting means,
A part of the drive circuit 35, the first drive motor 13 and the numerical control device 30 is a cutting means, a part of the numerical control device 30 is a position offset command means, and a part of the encoder 18a and the arithmetic circuit 41 is a servo error detection. A part of the numerical control device 30 is a meshing position calculating means, a spindle drive circuit 37,
A part of the spindle rotation drive motor 18, the encoder 18a and the numerical control device 30 serves as a meshing position correcting means, and the proximity sensor S, the spindle drive circuit 37, the spindle rotation drive motor 18, the encoder 18a and a part of the numerical control device 30. Respectively constitute the initial meshing means.

Next, the operation of this embodiment configured as described above will be described with reference to the flowcharts shown in FIGS. 3 and 7 and the explanatory diagrams shown in FIGS. 4 to 6 and 8. Numerical examples are for a spur gear with a module of 5 mm and 18 teeth.

First, as shown in step 101 of FIG. 3, the gear W is attached to the main shaft 16 and the operation button of the input / output device 33 is pressed.
And the grindstone shaft rotation driving motor 28 are operated in synchronization, so that the main shaft 16 and the grindstone shaft 26 are rotated at a predetermined rotational speed such that the grinding surface Gb of the threaded grindstone G can grind the tooth surfaces Wb and Wc of the gear W. Rotational driving is performed at a ratio, first, the initial tooth matching in step 102 is performed, and then step 10 which is the main part of the present invention
After the final tooth matching of No. 3 is performed, the gear W is ground by the screw-shaped grindstone G in step 104. The operations of steps 102 to 104 are continuously and automatically performed in the state where the main shaft 16 and the grindstone shaft 26 are rotationally driven in conjunction with each other as described above. The gear W supported on the Z-axis slide table 12 which is reciprocally driven by the second drive motor 14 is movable in a traverse direction (Z direction) parallel to its rotation axis, as shown in FIG. At the position indicated by the solid line which is different from the threaded grindstone G in the traverse direction, the initial tooth matching in step 102 is performed.

As shown in FIG. 5, this initial tooth engagement is performed by using a linear proximity sensor S of the eddy current type or the like, which is arranged in the radial direction with respect to the tooth portion Wa of the gear W. The tooth portion Wa of the gear W rotationally driven by the spindle rotation driving motor 18 alternately passes in front of the proximity sensor S, and the proximity sensor S has a spindle rotation angle within a range of about one tooth centered on the tooth bottom. With respect to the position, an output signal voltage is generated in which the central portion as shown in FIG. The CPU 31 detects the spindle rotation angle positions of the two points a1 and a2 at which this output signal voltage intersects a predetermined threshold voltage Va near the center of the left and right inclined portions, and the midpoint thereof is the tooth root center position θb. To detect as. The CPU 31 detects the tooth bottom center position θb of the gear W, the previously known positional relationship between the wheel spindle rotation angle position, and the thread portion Ga of the threaded grindstone G on the basis of the positional relationship between the screw grindstone G of the threaded grindstone G. The thread portion Ga coincides with the detected tooth bottom center position θb of the gear W (the thread portion Ga is the tooth portion Wa.
Of the gear wheel W with respect to the threaded grindstone G, such that the rotational angle position of the main shaft 16 is rotationally driven in conjunction with the grindstone shaft 26. Initial meshing is performed by offsetting in a predetermined rotation direction so that the meshing position is reached. This is the same as the technique described in the prior art, in which the position of each tooth portion of the gear that rotates with the main shaft is detected by the proximity sensor to perform the tooth matching between the gear and the threaded grindstone. The error of the initial tooth contact position is about several tens of microns on the tooth surface.
The proximity sensor S may be arranged in the axial direction with respect to the tooth portion Wa of the gear W.

After the initial tooth matching is performed, the final tooth matching shown in the flowchart of FIG. 7 is performed. The gear W is shown in FIG.
In the traverse direction, as shown by the solid line, which is different from the thread-shaped grindstone G, the main shaft 16 and the grindstone shaft 26 are driven in conjunction with each other.
The PU 31 determines the gain controller 43 in step 201.
To the position loop gain of the servo system of the gear side servo drive device from a normal high value suitable for grinding the tooth surfaces Wb and Wc of the gear W (for example, 8000 s ⁻¹ ) to a value significantly lower than that. For example, the value is 1/128 of the normal value). Next, the CPU 31 determines in step 202 that the first drive motor 1
3 to operate the main shaft 16 and the rotation axis of the main shaft 16 to the grindstone shaft 26.
Move forward in the direction of the cut that approaches the axis of rotation of. At this time, the thread portion Ga of the thread-shaped grindstone G enters between the tooth portions Wa of the gear W, but the inclined grinding surfaces Gb and Gc on both sides of the thread portion Ga are toothed within the error range of the initial meshing position. The predetermined position is set so as not to contact any of the tooth surfaces Wb and Wc of the portion Wa. A view of this state viewed from the traverse direction is shown by solid lines in FIGS. 8 (a) and 8 (b). Figure 8 (a)
6 is an explanatory diagram in the case where a positive direction position offset command is given in steps 203 to 206 to detect a positive direction servo error, and in a state immediately after the end of step 202, one ground surface of the thread ridge Ga is The gap angle along the pitch line WL of the gear W between Gb and the tooth surface Wb of the facing tooth portion Wa is Δθ _p1 . GL is a threaded grindstone G
Shows the pitch line of.

The CPU 31 gives a position offset command in the positive direction in step 203, whereby the gear W is offset in the positive rotation direction (clockwise direction in FIG. 8) by a predetermined minute amount (position offset amount), and the pitch line WL is obtained. Along the gap angle Δθ _p1 decreases by a predetermined position offset amount (for example, about 10 μm). Subsequently, the CPU 31 activates the second drive motor 14 in step 204 to set the gear W
From the position shown by the solid line in FIG. 4 to the position of the two-dot chain line WB (or from the position of the two-dot chain line WB to the position of the solid line)
Traverse is performed, and at the position of the alternate long and short dash line WA on the way, the servo error of step 205 (of the command value input to the spindle drive circuit 37 from the numerical controller 30 regarding the rotational angle position of the spindle 16 and the detection value input from the encoder 18a) is detected. difference)
Is detected, and in step 206, the servo error is compared with a predetermined set value. When it is determined that the servo error is smaller than the set value, the CPU 31 returns the control operation to step 203 and repeats steps 203 to 206. That is, until it is determined that the servo error is larger than the set value, a predetermined position offset command is sequentially given at the positions W and WB which are traverse ends, and the traverse operation for detecting the servo error is performed between the position W and the position WB. repeat.

If the accumulated value of the position offset amount increases due to this repetition and the value Δθ _c1 becomes larger than the initial clearance angle Δθ _p1 , the commanded position of the tooth surface Wb is the chain double-dashed line Wb2 of FIG. 8 (a). However, since the position loop gain of the servo system of the gear side servo drive device is lowered to a low value, at the position of the alternate long and short dash line WA, the position is larger than the position of the alternate long and short dash line Wb1 contacting the grinding surface Gb. The tooth surface Wb is not ground by advancing to the dashed-dotted line Wb2 side, and the gear W is rotated by the threaded grindstone G in this contact state. The servo error detected in step 205 in this state is shown in FIG.
Is the angle conversion value Δθ _e1 of the distance along the pitch line WL between the commanded position indicated by the two-dot chain line Wb2 and the actual position indicated by the one-dot chain line Wb1, and if this servo error Δθ _e1 is greater than the set value, the step If determined in 206, the CPU 31
Advances the control operation to step 207 to store this servo error Δθ _e1 in the positive direction in a predetermined area in the memory 32. The detection of the servo error in step 205 is performed while the gear W and the threaded grindstone G are rotating as in the case of grinding. Therefore, if there is an eccentricity error, a pitch error, a tooth profile error, etc., for each tooth portion Wa. Will have different values. Therefore, the servo error in step 205 uses their average value.

Subsequently, the CPU 31 causes the gear W and the screw-shaped grindstone G.
After returning the positional relationship of 1 to the state immediately after the end of step 202, the negative direction servo error Δθ _e2 is detected and stored in a predetermined area in the memory 32 in steps 208 to 212. The details are given in step 203 except that a position offset command in the negative direction is given in step 207.
~ Since it is the same as step 207, detailed description will be omitted. Note that FIG. 8 is a schematic explanatory diagram, and Step 2
02, the tooth surfaces Wb and Wc and the ground surface G in the state immediately after the end, that is, the state in which the final tooth matching is not substantially started.
The gap angles Δθ _p1 and Δθ _p2 between b and Gc are considerably larger than the detected servo errors Δθ _e1 and Δθ _e2 .

At the following step 213, the CPU 31 causes the tooth surfaces Wb and Wc and the ground surface G immediately after the end of step 202.
The gap angles Δθ _p1 and Δθ _p2 between b and Gc are calculated by the following equation 1.

[0026]

## EQU1 ## Δθ _p1 = Δθ _c1 −Δθ _e1 Δθ _p2 = Δθ _c2 −Δθ _e2 Next, the CPU 31 proceeds to step 214 and step 202.
Position offset amount Δθ from the initial meshing position immediately after the end to the optimum meshing position where the gaps between the grinding surfaces Gb, Gc and the tooth surfaces Wb, Wc on both sides of the thread Ga are the same.
m is calculated by the following equation 2.

[0027]

## EQU2 ## Δθm = (Δθ _p1 −Δθ _p2 ) / 2 However, the sign of Δθm is the same as the direction of the position offset command described above.

Next, in step 215, the CPU 31 gives a position offset command corresponding to this position offset amount Δθm to the gear side servo drive device, offsets the gear W in the rotational direction, and is shown by a broken line Wbm in FIG. 8C. like,
The gaps between the tooth surfaces Wb and Wc of the gear W and the grinding surfaces Gb and Gc on both sides of the threaded grindstone G are set to be the same. Then, in step 216, the position loop gain of the servo system of the gear side servo drive device is raised to a normal high value suitable for grinding the tooth surfaces Wb and Wc of the gear W, and the final tooth matching shown in the flowchart of FIG. 7 is completed. . Since the resolution of the rotational direction position detection of the gear W in the case of this final tooth matching is about 0.25 μm on each tooth surface Wb, Wc, the error of the tooth matching in the final tooth matching is smaller than that in the case of initial tooth matching. Is also much smaller.

After the final tooth matching shown in the flow chart of step 4 is completed, the CPU 31 proceeds to step 104 of the flow chart of FIG.
14 is operated to reciprocally traverse the gear W from the position shown by the solid line in FIG. 3 to the position shown by the chain double-dashed line WB.
Further, by cutting the gear W to a predetermined position in a predetermined sequence and grinding the gear W with the threaded grinding wheel G,
Both tooth surfaces Wb and Wc are always ground uniformly.

[0030]

According to the present invention described above, since the servo error is detected by applying the position offset command in both the forward and reverse directions in the state where the position loop gain is switched to a low value, both tooth surfaces of the tooth portion are detected. Each position can be accurately detected without grinding. The optimum meshing position is calculated based on the positions of both tooth flanks that are accurately detected in this way, and the meshing position is corrected. Can be achieved with.

Since the position loop gain suitable for grinding is higher in the servo system of the gear side servo drive device, it is easier to implement the present invention by switching it to a lower value. In addition, when the thread grindstone and the gear do not mesh with each other in the traverse direction and do not mesh with each other, the position loop gain is switched to a low value and the position offset command is given to detect the servo error by the traverse. The risk of damaging the gear and / or the threaded grindstone at the time of meshing due to the erroneous operation of is reduced.

Further, the tooth portion of the rotating gear is detected by the proximity sensor to determine the initial tooth-matching position between the screw-shaped grindstone and the gear, and a cut is made at this initial tooth-matching position to detect the servo error. In this case, since the initial tooth matching and the subsequent correction of the meshing position due to the servo error can be continuously performed, the processing time can be shortened as a whole.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment of an automatic tooth aligning device in a gear grinding device according to the present invention.

FIG. 2 is a diagram showing a configuration of a gear side servo drive device of the embodiment shown in FIG.

3 is a flowchart of the overall operation of the embodiment shown in FIG.

FIG. 4 is a diagram showing a traverse state of the embodiment shown in FIG. 1.

5 is a diagram showing a relationship between a proximity sensor used for initial meshing and a gear of the embodiment shown in FIG.

6 is a diagram showing an example of an output signal of the proximity sensor of FIG.

FIG. 7 is a flowchart of final tooth matching of the embodiment shown in FIG.

8 is an explanatory diagram of final tooth matching of the embodiment shown in FIG. 1. FIG.

[Explanation of symbols]

16 ... Spindle, 26 ... Grindstone axis, 30 ... Control device (numerical control device), G ... Threaded grindstone, Ga ... Thread portion, Ga, Gb
... Grinding surface, S ... Proximity sensor, W ... Gear, Wa ... Teeth, W
b, Wc ... Tooth surface.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Wang Lei Aoba, Aoba-ku, Aoba-ku, Sendai-shi, Miyagi Aoba Tohoku University (72) Inventor Yasushi Teshikaga, Aoba-ku, Aoba-ku, Sendai, Miyagi Aoba, Tohoku University (72) Invention Yuuji Kato Aoba, Aoba-ku, Sendai-shi, Miyagi Aoba Tohoku University (72) Inventor Hisashi Nakamura 1-1 Asahi-cho, Kariya-shi, Aichi Toyota Koki Co., Ltd. (72) Masanori Yamanaka Asahi, Kariya-shi, Aichi 1-chome, Toyoda Machinery Co., Ltd.

Claims (4)

[Claims] 1. A gear-side servo drive device that rotates a main shaft that connects gears and rotates integrally with the gear, a grindstone-side servo drive device that rotationally drives a grindstone shaft provided with a screw-shaped grindstone, and both of the above. A control device that gives a command to a servo drive device to control the positions of the spindle and the grindstone shaft in the rotational direction so that the inclined grinding surface of the thread portion of the threaded grindstone grinds the tooth surface of the tooth portion of the gear. And a gain adjusting means for selectively switching the position loop gain of at least one of the servo systems of the two servo drive devices between a high value suitable for grinding and a value significantly lower than that. Cutting means for making a cut to such an extent that the screw thread portion enters between the tooth portions, but the two do not contact each other, and the position loop gain is switched to the low value and the cut is made. In this state, at least one of the servo drive devices is provided with a position offset command in both forward and reverse rotation directions such that the distance between the ground surface of the thread portion and the tooth surface of the tooth portion gradually decreases. Position offset command means, the position loop gain and the command value given the position offset command by the position offset command means of the position of the spindle or grindstone shaft corresponding to the servo drive device is switched to the low value and the actual Servo error detecting means for detecting a servo error which is a difference from a detected value which is a position, and a meshing position for calculating an optimum meshing position based on each servo error in both forward and reverse directions detected by the servo error detecting means. A calculation unit and a mesh position correction hand for correcting the mesh position based on the optimum mesh position calculated by the mesh position calculation unit. Automatic tooth alignment apparatus in gear grinding apparatus comprising the. 2. The gain adjusting means selectively switches the position loop gain of the servo system of the gear side servo drive device between a high value suitable for grinding and a value significantly lower than it. An automatic gear matching device in the gear grinding device according to 1. 3. In a state where the thread-shaped grindstone and the gear disagree with each other in a traverse direction substantially parallel to the axial direction of the latter and do not mesh with each other, the position offset command is given by the position offset command means, and then the gear is moved. 3. The automatic tooth-matching device in a gear grinding machine according to claim 1, wherein the servo-error detecting means detects the servo error by moving the thread-shaped grindstone in a traverse direction. 4. An initial tooth aligning means for detecting a tooth portion of the gear by a proximity sensor to calculate an initial tooth aligning position at which a thread portion of the threaded grindstone approximately coincides with an intermediate position of the tooth portion of the gear. 4. The automatic tooth-matching device in the gear grinding machine according to claim 1, 2 or 3, further comprising: a cutting means for providing the cutting at the initial meshing position.