JPH04336915A - Tooth alignment method for nc device - Google Patents

Abstract

PURPOSE:To enable a pitch error to be easily measured on a shaving cutter before and after machining, and further enable the initial engagement phase of a gear to be automatically set at the center of a machining allowance in the case of a hard shaving cutter. CONSTITUTION:Angle detection encoders 5 and 6 are fitted for detecting the rotational positions of a gear-shaped tool 1 and a machined gear 2. While the encoders 5 and 6 are rotating by an angle corresponding to the integer times rotation of the gear 2, the readings of both encoders 5 and 6 are stored at every fine angle of the tool 1. Then, the gear 2 is caused to rotate in a reverse direction, and the readings of the encoders 5 and 6 are similarly stored. Furthermore, a difference in the readings of the encoders 5 and 6 between normal and reverse rotations is obtained. In the case of hard shaving, a half of the maximum of the difference is taken as a machining allowance center and added to the theoretical value of the encoder 6 for positioning the shaft of the tool 1.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a CNC system that controls a gear processing machine using a shaving cutter or a gear-shaped grindstone.
The present invention relates to a method of gearing an NC device for measuring the pitch accuracy of a gear to be machined before or after machining on the machine and meshing a tool gear and a gear to be machined.

0002

[Prior Art] In the conventional shaving method known as a gear processing method, a shaving cutter, which is a tool, is rotated by a drive motor, and one of the gears to be processed is driven by the cutter, and the tooth surfaces are cut by the sliding of the tooth surfaces of both gears. That's what I do. Therefore, since there is no function to maintain the meshing phase of both gears constant, there is a drawback that it is difficult to correct the pitch error of the gear to be machined before machining. Therefore, it was an essential step to measure the pitch error after processing.

On the other hand, in recent years, a hard shaving method has been developed as a method for solving the above-mentioned drawbacks and for finishing gears after heat treatment. In hard shaving processing, a gear-shaped CNB grindstone is used, but the principle of cutting or grinding by sliding is exactly the same as in the shaving method. However, in order to machine gears after heat treatment, the tool and workpiece must be driven synchronously, so the tool axis and workpiece axis are driven by separate drive motors, and both drive motors are electrically synchronously controlled. A method has been developed to do so. In this case, unlike the conventional method, the rotational phase of both is constrained to a constant value, so the phase relationship between the two when installing the workpiece must always be such that the machining allowance is equal on both tooth surfaces. . Therefore, when attaching a workpiece manually, the meshing is set so that it is approximately centered, the phase relationship is electrically memorized, and the workpieces are rotated synchronously to perform the machining.

0004

[Problems to be Solved by the Invention] Two-tooth meshing tests and one-tooth meshing tests are well known as methods for easily measuring the pitch of gears (for example, "Recent Automatic Gear Accuracy Measuring Techniques") Research Vol. 34 No. 11)
However, in the two-tooth mesh test, the master gear and the gear to be measured are meshed without backlash, so if the master gear is a tool, as is the purpose of this invention, the meshing will result in cutting. Otherwise, there is a problem that the tool is ground or the tooth surface of the tool is damaged. Therefore, a two-tooth surface meshing test is not preferred, and a single tooth surface meshing test is appropriate.

[0005] In this measurement method using a single tooth meshing test, encoders are attached to both the rotating shafts of the master gear and the gear to be measured, and the master gear is driven, and the master gear driven by the master gear is transmitted to the gear to be measured. The rotation angle relative to the rotation angle of the gear is detected, and the transmission error is calculated from that value and the theoretical tooth number ratio. However, even in this method, the shaft of the gear to be measured is braked so that the tooth surface of the gear to be measured and the tooth surface of the master gear come into close contact, and the gear is driven while applying a constant torque. There is a problem in that this has an unfavorable effect on the purpose of application of the present invention, which is to perform on-machine measurement of pitch accuracy in a machine that performs machining by meshing a shaped tool and a gear to be machined.

An object of the present invention is to provide a CNC device that controls the rotation of the tool gear and the workpiece gear with a built-in function to automatically measure the pitch error of the workpiece gear, thereby measuring the pitch error of the workpiece gear on the machine. CNC with the function of measuring
By providing a device, it is possible to easily measure the pitch error after machining without using a pitch error measuring device on a shaving machine, and it is possible to easily measure the pitch error after machining without using a pitch error measuring device on a shaving machine. Even if the machining allowance is small,
To enable machining of both tooth surfaces without leaving any uncut parts.

[0007]

[Means for Solving the Problems] The present invention has been made in view of the above objects, and provides a gear for machining a tooth surface by rotating a gear-shaped tool and meshing a gear to be machined with the gear-shaped tool. In the NC control device of the processing machine, the rotational position of the gear is detected by an angle detection encoder coupled to the tool axis of the gear-shaped tool and the mounting axis of the gear to be machined, and the rotational position of the gear is connected to the tool axis of the gear-shaped tool. After rotating forward by an angle sufficiently larger than the angle of one tooth, storing the values of both encoders for each minute angle of the gear-like tool while rotating the gear by an angle corresponding to an integral multiple of the rotation of the gear to be machined, and further After rotating by a sufficiently large angle and stopping, the tool is rotated in the reverse direction and the values of both encoders are stored in the opposite direction for each minute angle of the gear-shaped tool from the angle at which the storage of the encoder values during the forward rotation is completed. , find the difference between the encoder value of the tool axis stored at each point of the minute angle and the encoder value of the attachment axis of the workpiece gear, and use half of the maximum value of the data group of the difference as the machining allowance. The tool axis is positioned at a position where the value of the center of the machining allowance is added to the theoretical value of the encoder of the attachment axis of the gear to be machined, which is calculated from the tooth number ratio of the gear-shaped tool and the gear to be machined. The above problem has been solved by providing a method for aligning teeth of an NC device characterized by the following.

Furthermore, in the present invention, the gear-like tool is rotated,
In an NC control device for a gear processing machine that processes a tooth surface by meshing a workpiece gear with the gear-like tool, an angle detection encoder coupled to a tool shaft of the gear-like tool and a mounting shaft of the workpiece gear; After detecting the rotational position of the gear and rotating the tool shaft in the forward direction by an angle sufficiently larger than the angle of one tooth of the gear-like tool, the rotation position of the gear is rotated through an angle corresponding to an integral multiple of the rotation of the gear to be machined. The values of both encoders are stored for each minute angle of the gear-like tool, and after the tool is rotated by a sufficiently large angle and stopped, the tool is rotated in the reverse direction and the values of the encoders are calculated from the angle at the end of storing the encoder values during the forward rotation. The values of both the encoders are stored in opposite directions for each minute angle of the gear-like tool, and the values of the encoder of the attachment shaft of the gear to be machined corresponding to the encoder values of the tool axis for each rotation direction and the gear are stored. The difference between the theoretical value of the encoder of the mounting shaft of the gear to be machined, which is calculated from the ratio of the number of teeth between the shaped tool and the gear to be machined, is determined to be the cumulative pitch error of the gear to be machined, and the maximum value of the cumulative pitch error and An NC device characterized in that a minimum value, a median value, and an average value are determined, the difference between the median values during forward rotation and reverse rotation is used as a backlash, and the tool axis is positioned at a position half of the difference between the median values. The above problem was solved by providing a tooth alignment method.

[0009]

[Operation] By having the above-described structure, the present invention can drive at least one axis without adding any special equipment in a machine that performs machining by meshing a gear-like tool with a workpiece gear. This not only makes it possible to measure the pitch of the gear to be machined on-machine, making it possible to judge whether it is good or bad, but also allows for the installation of the gear to be machined and the appropriate meshing phase in a machine that drives both gears separately and processes them in synchronization. settings can be done automatically.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described in detail with reference to the accompanying FIGS. 1 to 4. Fig. 1 is a block diagram showing the general configuration of a machine and a control device according to an embodiment of the present invention, and Fig. 2 shows an encoder of the drive shaft obtained by rotating the tool shaft in normal and reverse directions in order to measure the pitch error, and its encoder. 3 is a graph showing the value of the angle count pulse obtained from the encoder of the driven shaft, and FIG. 3 is a graph showing the method of finding the engagement position by finding the maximum value of the pitch error and backlash obtained from FIG. 2. FIG. 4 is a graph diagram for determining average values of pitch error and backlash.

In FIG. 1, a gear-shaped tool (tool gear)
1 and the workpiece gear 2 are directly connected to a tool gear drive motor 3 and a workpiece gear drive motor 4, respectively, and the drive motors 3 and 4 are further connected to encoders 5 and 6 for detecting rotation angles. On the other hand, the control system is controlled by the command center 13 of the NC device 17.
Based on the position command from the position controllers 9 and 10, the values of the current position counters 11 and 12, which are connected to the encoders 5 and 6 and count the pulses input therefrom, are calculated, and the values are calculated as a speed command by the speed controller 7. , 8. The speed control units 7 and 8 perform feedback control on the motors 3 and 4 based on the speed command and a speed signal obtained by F/V conversion of the output pulses of the encoders 5 and 6, and the motors 3 and 4 are controlled by this control. Can be rotated properly.

The current position counter 11, 1 obtained here
The current position information in step 2 is sent to the CPU 14 in order to calculate the pitch error and tooth alignment center of the present invention. Furthermore,
All information including other measurement information can be displayed on the display device 15 and outputted to the outside from the output port 16 for use.

According to the embodiment of the present invention, when it is applied to a shaving machine, it is not necessary to drive the gear to be machined, so the drive motor 4 and speed control section 8 shown in FIG. 1 are not essential. Only the encoder 6 is coupled to the gear to be machined, and its output is only input to the current position counter 12.

Next, a method for measuring pitch error will be explained with reference to FIG. When in a stopped state, a tool gear 1 and a workpiece gear 2 are engaged with each other with backlash, and a tool gear drive motor 3 is rotated at low speed. Since the gear shaft to be machined is stopped due to some frictional resistance, it will eventually be driven by the tool gear. In FIG. 2, the count value X of the encoder 5 of the tool gear shaft and the encoder 6 of the work gear
A graph showing the relationship between Y and the count value Y is shown. In FIG. 2, when the tool shaft is rotated from point P, the gear to be machined begins to follow from point R after first rotating by the amount of backlash rotation. If the tool gear is rotated beyond the rotation angle of one tooth, the backlash will definitely be removed and contact will be made, so the measurement start time is set at point A1, which is the point at which the tool gear is rotated beyond that angle. Encoder values X and Y are stored in a memory for each minute angle of X from point A1, and the tool gear is rotated by a rotation angle corresponding to one rotation of the gear to be machined or an integral multiple thereof. FIG. 2 illustrates an example of one rotation.

[0015] Data acquisition is completed at point A2, but
After that, the tool is rotated sufficiently, and then the rotation is stopped, and then the tool gear is reversed. The reason for the extra rotation is that the gear shaft to be machined has spring properties in the direction of rotation due to seal resistance, etc., and when the tool axis is reversed, the gear to be machined on the driven shaft automatically rotates by that amount. This is because the tooth surfaces may not come into contact even if the tooth surfaces are rotated by an angle corresponding to backlash. When the point is reversed from point O, the shaft of the gear to be machined rotates in the same direction until point S, and eventually both tooth surfaces separate, and as the tool gear rotates further, it comes into contact with the opposite tooth surface, and then The point further rotated is point B1. Here, the angle of the tool axis is the same at point B1 and point A2. B
Data is similarly stored from point 1 and ends at point B2. If the relationship between the angle data X and Y obtained in the process up to now is shown in a graph, it will be as shown in FIG.

[0016] Here, the difference between the value Y indicating the angle of the gear shaft to be machined during forward rotation and reverse rotation detected and stored at the same angle of X is determined. This is shown in the X-Y' graph of FIG. The curve n shown here corresponds to the backlash of the gears to be machined that are meshed according to the angle of the tool gear, and its maximum value y0 is the maximum value of the backlash, which is the difference between B0 and A0 in Fig. 2. It is synonymous with difference. Therefore, if the center of the machining allowance is positioned at point M, which is half of this backlash, both tooth surfaces can be machined without leaving anything behind.

On the other hand, the rotation angle of the driven shaft relative to the rotation angle of the drive shaft can be easily obtained from the transmission ratio determined by the ratio of the number of teeth of both gears. The slope of a straight line m indicating the theoretical angular relationship of gears passing through point M in FIG. 2 is the transmission ratio. This transmission ratio is K
If the memorized angle of the gear to be machined during normal rotation at X0 is Y0, the tooth alignment position y at any angle can be easily obtained from the theoretical straight line m, and can be calculated using the following equation.

[0018]y=[Y0 +(y0/2)]+K・x

Therefore, in the present invention, during normal rotation, the value of the angle complete.

[0020]x=[y-(Y0 +y0/2)]/K

Next, a method for determining the average value of pitch error and backlash will be explained based on FIG. In Fig. 4, a straight line J passing through point A1 indicates the theoretical angular relationship of gears.
The slope of is the transmission ratio. If this transmission ratio is K and the value of Y at X1 is Y1, the difference y between the theoretical straight line J and the memorized measured value in the forward direction can be easily obtained, and in the present invention, the following equation is used. Calculate with.

[0022]y=(Y-Y1)・K

Similarly, the difference between the theoretical value and the measured value at the time of reverse rotation can be calculated. If the tool gear is of ideal shape, the resulting difference value represents the cumulative pitch error of the gear. In addition, the maximum value of the cumulative pitch error during forward rotation is au, the minimum value is al, and the average value is ao, and the maximum value during reverse rotation is bu, the minimum value is bl, and the average value is bo.
can be easily obtained as As a result, the average value of backlash is given as bo − ao.

Furthermore, when applying to the above-mentioned hard shaving machine and setting the initial phase of the gear, since the center of the machining allowance is located in the middle between bo and ao, the equations of the respective straight lines are expressed as ya and yb. and,

[0025]ya=Kx+ayb=
Kx + b

[0026]The center line yc is yc =
Since ya + (yb - ya)/2,

[
[0027]yc=Kx+(a+b)/2

0
The tooth alignment angle X of the tool axis corresponding to the value of the current count value Y of the gear axis to be machined can be calculated as
is generally,

[0029]X=[Y-(a+b)/2]/K

003
0] can be calculated and positioned.

[0031]

As explained above, according to the CNC device of the present invention, the pitch error of gears can be measured in the process before and after machining on a shaving machine, eliminating the need for a pitch error measuring device and improving hard shaving. On a machine, the tool gear and the workpiece gear can be meshed at a position close to the center of the teeth, regardless of the condition of the workpiece gear, so even if the machining allowance is small, both tooth surfaces are left uncut. Now you can process it without any need for it.

[Brief explanation of drawings]

FIG. 1: A control device for controlling a gear processing machine that can embody an embodiment of the present invention.

[Fig. 2] Graphical representation of angle counting pulses obtained from the encoders of the tool axis and driven axis by the apparatus of Fig. 1.

[Figure 3] Graph diagram showing how to find the maximum value of pitch error and backlash

[Figure 4] Graph diagram showing how to calculate pitch error and backlash values

[Explanation of symbols]

1: Tool gear 2: Gear to be machined 3: Tool gear drive motor 4: Workpiece gear drive motor 5, 6: Encoder 7, 8: Speed control section 9, 10: Position control section 11, 12: Current position counter 13: Position command section 14: CPU for pitch measurement 15:CRT 16: External output port 17:NC device

Claims (2)

[Claims] 1. An NC control device for a gear processing machine which rotates a gear-like tool and engages a workpiece gear with the gear-like tool to machine a tooth surface. After detecting the rotational position of the gear by an angle detection encoder connected to the gear mounting shaft, and rotating the tool shaft forward by an angle sufficiently larger than the angle of one tooth of the gear-like tool, While rotating an angle corresponding to an integral multiple of rotation, the values of both encoders are memorized for each minute angle of the gear-like tool, and after further rotating by a sufficiently large angle and stopping, the tool is rotated in the reverse direction and rotated in the normal rotation. The values of both encoders are stored in the opposite direction for each minute angle of the gear-shaped tool from the angle at the end of storing the encoder values, and the encoder values of the tool axis stored at each point of each minute angle are The difference between the value of the encoder of the mounting shaft of the gear to be machined is determined, half of the maximum value of the data group of the difference is set as the center of the machining allowance, and the machining allowance is calculated from the ratio of the number of teeth of the gear-shaped tool and the gear to be machined. A method for gear alignment of an NC device, characterized in that the tool shaft is positioned at a position obtained by adding a value of the center of the machining allowance to a theoretical value of an encoder of the mounting shaft of the gear to be machined. 2. An NC control device for a gear processing machine that rotates a gear-like tool and engages a workpiece gear with the gear-like tool to perform tooth surface machining, wherein the tool axis of the gear-like tool and the workpiece After detecting the rotational position of the gear by an angle detection encoder connected to the gear mounting shaft, and rotating the tool shaft forward by an angle sufficiently larger than the angle of one tooth of the gear-like tool, The values of both encoders are memorized for each minute angle of the gear-like tool while the tool is rotated through an angle corresponding to an integral multiple of rotation, and after further rotation by a sufficiently large angle and stopped, the tool is rotated in the reverse direction and rotated in the normal direction. The values of both encoders are stored in opposite directions for each minute angle of the gear-like tool from the angle at the end of storing the encoder values, and the encoder values corresponding to the encoder values of the tool axis for each rotation direction are stored. The difference between the encoder value of the attached shaft of the processed gear and the theoretical value of the encoder of the attached shaft of the processed gear calculated from the tooth number ratio of the gear-like tool and the processed gear is calculated, and the cumulative value of the processed gear is calculated. The maximum value, the minimum value, the median value, and the average value of the cumulative pitch error are determined as the pitch error, and the difference between the median values during forward rotation and reverse rotation is defined as the backlash. A method for aligning teeth of an NC device, characterized by positioning a tool axis.