JPH0623408Y2 - Spindle position detection device for numerically controlled grinding machine - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a device for detecting the rotational position of a spindle of a numerically controlled grinding machine that grinds a non-round work piece such as a cam (hereinafter, also simply referred to as "workpiece").

[Prior art]

Conventionally, a method is known in which a numerical control device controls the feed of a grinding wheel in the direction perpendicular to the spindle axis in synchronization with the spindle rotation, and grinds a workpiece such as a cam. To control the feed of the grinding wheel synchronously, it is necessary to add profile data to the numerical controller. This profile data gives the amount of movement of the grinding wheel for each unit rotation angle of the main shaft so that the grinding wheel reciprocates along the finished shape of the workpiece, that is, the profile generating movement. On the other hand, in order to grind a workpiece, in addition to the profile data, machining cycle data for controlling the machining cycle such as feed, cutting, and retreat of the grinding wheel is necessary. The workpiece is machined by numerically controlling the rotation of the spindle and the feed of the grinding wheel based on this machining cycle data and profile data. Especially, in the case of constant size grinding, the size of the base circular bottom is measured. Therefore, it is necessary to give the sampling timing of the sizing signal. For this reason, it is necessary to detect the rotation angle phase of the main shaft, and in a conventional grinding machine, a limit switch, a proximity switch, etc. were provided at a position where a detection signal was output when the base circular bottom was measured.

[Problems to be solved by the device]

However, in the method of detecting the rotational phase of the spindle by using a limit switch or the like as in the conventional grinder, there is a problem that the detected phase range is fixed once the limit switch is arranged on the table. Therefore,
When processing a camshaft in which a plurality of cams having different phases on the bottom of the base circle are attached, it is necessary to provide a plurality of limit switches corresponding to each cam. The present invention has been made to solve the above problems, and an object thereof is to facilitate detection of the rotational phase of a spindle in a variable range.

[Means for solving problems]

The structure of the device for solving the above-mentioned problems is, in a spindle position detecting device of a numerically controlled grinding machine for machining a workpiece having a plurality of non-round portions, a sizing device for measuring the non-round portion, and a spindle. A rotation angle detecting means and a detection range for storing data indicating a rotation angle detection range corresponding to the outer peripheral portion of the non-true circular portion to be measured by the sizing device in association with each of the plurality of non-true circular portions. Storage means, detection range extraction means for extracting data indicating a detection range corresponding to a non-round portion to be processed from data indicating a plurality of detection ranges, and rotation angle position detected by the spindle rotation angle detection means. That is, a detection signal output unit that outputs a detection signal based on the data indicating the detection range extracted by the detection range extraction unit is provided.

[Action]

A sizing device measures the diameter of the non-round portion of a workpiece having multiple non-round portions. Further, in the detection range storage means, the detection range is set as data for each non-true circular portion in order to give the timing for sampling the output signal of the sizing device, for example, the base circle portion of the cam.
Further, from the data indicating the detection range set in the detection range storage means, the data indicating the detection range corresponding to the non-round portion being processed is extracted. Then, the detection signal output means outputs a detection signal based on the rotation angle position detected by the spindle rotation angle detection means and the data indicating the detection range extracted by the detection range extraction means. As a result, if the measurement value of the diameter is sampled by the sizing device at the timing when the detection signal is output, for example, the diameter of the non-round portion in a predetermined detection range such as the base circle can be measured. As described above, in the case of a workpiece having a plurality of non-true circular portions having different rotation angle phases, it is only necessary to set data indicating the detection range for each non-true circular portion in the detection range storage means. The measurement timing of the diameter of the true circular portion can be obtained.

【Example】

Hereinafter, the present invention will be described based on specific examples. FIG. 1 is a block diagram showing a numerical control grinding machine. Reference numeral 10 denotes a bed of a numerically controlled grinding machine, on which a table 11 driven by a servomotor 16 via a screw feed mechanism is slidably arranged in the Z-axis direction parallel to the spindle axis. . A headstock 12 in which a spindle 13 is mounted is arranged on the table 11, and the spindle 13 has a servomotor 14
Is rotated by. A tailstock 15 is placed on the right end of the table 11, and the center 19 of the tailstock 15 and the spindle 1 are mounted.
A workpiece W composed of a cam shaft is held by the center 17 of the three. The workpiece W is fitted into the positioning pin 18 provided so as to project from the spindle 13, and the rotation phase of the workpiece W matches the rotation phase of the spindle 13. A tool base 20 that can move back and forth toward the workpiece W is guided behind the bed 10, and a grinding wheel G that is driven to rotate by a motor 21 is supported on the tool base 20. The tool base 20 is provided with a servo motor 23 via a feed screw (not shown).
And is moved forward and backward by the forward and reverse rotation of the servo motor 23. On the other hand, in front of the bed 10, a sizing mechanism 60 for measuring the diameter of the workpiece W is provided so as to be slidable in the U-axis and V-axis directions. The sizing circuit 61 positions the sizing mechanism 60 in the U and V directions. Further, the sizing mechanism 60 is provided with a pair of contacts 62 whose offset distance can be adjusted. The offset interval is set by the numerical control device 30 via the sizing circuit 61 to the machining size of the workpiece W. When the diameter of the workpiece W is measured, the distance between the contacts 62 changes according to the variation in the diameter of the workpiece W, and the displacement having the set offset distance as the zero point is output to the sizing circuit 61 as an electric signal. It The sizing circuit 61 inputs a detection signal from the numerical controller 30 indicating that the rotation angle phase of the main shaft 13 is in the phase in which the diameter of the base circular bottom of the cam is measured by the contactor 62. When input, when the distance between the contacts 62 is equal to the set offset distance, the sizing signal is output to the numerical controller 30. The drive units 40, 41, 42 are the numerical control device 30.
Input the command pulse from the servo motor 2
This is a circuit for driving 3, 14, and 16. Each servo motor 23, 14, 16 has a pulse generator 5
2, 50, 54 and speed generators 53, 51, 55 are coupled, and their outputs are fed back to the respective drive units for feedback control of speed and position. In addition, each drive unit is equipped with a current value counter that counts feedback pulses, and the contents are always
It is held in the spindle rotation angle register 351 of the numerical controller 30. The numerical controller 30 mainly includes the servo motors 23, 14,
This is a device for controlling the grinding of the workpiece W by numerically controlling the rotation of 16. A tape reader 43 for inputting profile data, processing cycle data, etc., a keyboard 44 for inputting control data, etc., and a CRT display device 45 for displaying various information are connected to the numerical controller 30. As shown in FIG. 2, the numerical controller 30 mainly includes a main CPU 31 for controlling the grinder, a ROM 33 storing a control program, a RAM 32 storing input data, an input / output interface 34 and an output latch circuit 38. It is configured. On the RAM 32, an NC data area 321 that stores NC data, a profile data area 322 that stores profile data, and a detection range data area 3 that stores the upper limit value and the lower limit value of the detection range of the spindle rotation angle.
And 23 are provided. Output latch circuit 38 is spindle 1
3 is a circuit that outputs a high-level detection signal while the rotation angle phase of 3 is in the detection range. The numerical control device 30 is provided with a drive CPU 36, a RAM 35, and a pulse distribution circuit 37 as a drive system for the other servomotors 23, 14, 16. The RAM 35 is a spindle rotation angle register 351 that holds the current position of the spindle 13 managed by the drive circuit 41.
Is a storage device which has the main CPU 31 and inputs positioning data of the grinding wheel G from the main CPU 31. The drive CPU 36 is a device that performs calculations such as slow-up, slow-down, interpolation of target points, etc., regarding the feed of the grinding wheel G, and outputs the positioning data of the interpolation points at a fixed cycle. Command pulse is sent to each drive unit 40,
This is a circuit for outputting to 41 and 42. Next, the operation will be described. The detection range data is input from the keyboard 44 and RAM3
2 is set in the detection range data area 323. As shown in FIG. 5, the detection range data area 323 is a data table DT that stores the lower limit value and the upper limit value of the range of the rotation angle of the spindle at which the diameter of the bottom of the base circle should be detected by the contactor 62 for each cam. And the data table DT has a workpiece W
They are grouped according to the type of camshaft they are. The detection range data area 323 further has detection range registers RA and RB in which detection range data A and B (A is a lower limit value and B is an upper limit value) corresponding to the cam being machined are stored. The upper limit value A and the lower limit value B are determined by the spindle 13
The direction in which the phase advances with respect to the positive rotation of is the upper limit. The main CPU 31 performs processing according to the flowcharts of FIGS. First, the type of the work (camshaft) is discriminated from the data input from the keyboard 44 (step 100, hereinafter, only the number is described), and the NC data for machining the work is read from the NC data area 321. Selected (102). Next, the address on the data table DT of the detection range data corresponding to the cam processed according to the NC data is calculated (10
4) The detection range data stored at that address is set in the detection range registers A and B (106). Then, a grinding process is executed based on the NC data and the profile data (108). During this grinding process, the sizing circuit 61
When a sizing signal is input from, the grinding process is completed through processes such as cutting stop, spark-out processing, and tool retreat. After the grinding process is completed, it is judged whether or not the machining of all the cams is completed (110). When it is judged that the machining is completed, the execution of this program is ended, but it is judged that there is an unmachined cam. In step S104, the processing of the CPU 31 returns to step 104, and the processing for the next cam is executed. In addition to the machining process described above, a program for detecting the rotational position of the spindle shown in FIG. 4 is executed by a timer interval interrupt. First, the current rotation angle θ of the spindle 13 is read from the spindle rotation angle register 351 (200), and the value θ is compared with the size of the lower limit value A stored in the detection range register RA (202). When it is determined that θ ≧ A, it means that the current rotation angle θ of the main spindle exists within the detection range, and the high level detection is performed by setting the external signal terminal of the output latch circuit 38 to the high level. The signal is output (20
4). On the other hand, if the determination result in step 202 is NO, the current rotation angle θ is compared with the magnitude of the upper limit value B stored in the detection range register RB (206). When it is determined that θ> B, it means that the current rotation angle θ of the main shaft is out of the detection range. By setting the external signal terminal of the output latch circuit 38 to low level, the detection signal becomes low. It becomes a level (208). In addition, the determination result of step 206 is
If NO, the program is terminated without changing the level of the external signal terminal of the output latch circuit 38. For this reason,
Level fluctuation of the detection signal does not occur. After all, the relationship between the detection signal and the detection range is as shown in FIG. In either case, the detection signal has a high level when the rotation angle of the spindle 13 is not less than the lower limit value A and not more than the upper limit value B of the detection range, and has a low level in other cases. As described above, the apparatus of this embodiment has the detection range registers RA and R.
Since it is possible to easily change the detection range of the rotation angle phase of the main shaft simply by changing the content of B, it is effective for the constant-size grinding of the cam shaft having a plurality of cams having different phases.

[Effect of device]

The present invention provides data showing the detection range of the rotation angle corresponding to the outer peripheral portion of the non-round portion to be measured by the sizing device,
It is stored in association with each of a plurality of non-round portions, and data indicating the detection range corresponding to the non-round portion to be processed is extracted, and based on the detected rotation angle position and data indicating the detection range. , A device that outputs a detection signal. Therefore, it becomes possible to sample the measured value of the diameter in the sizing device at the timing when the detection signal is output, for example, in the range of the base circle of the cam, and it is possible to obtain the accurate dimension of the non-round portion. . Further, when a plurality of non-true circular portions are present in one workpiece, data indicating the respective detection ranges may be set in the detection range storage means. Further, even when the workpiece changes, the sampling range of the measurement signal output by the sizing device can be easily changed by simply changing the data indicating the detection range set in the detection range storage means. Therefore, unlike the conventional device, a large number of limit switches and the like are not required, so that the structure of the device is simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing a numerical control grinder in which a spindle rotational position detecting device according to an embodiment of the present invention is used. Second
The figure is a block diagram showing the electrical configuration of the numerical controller. FIG. 3 and FIG. 4 are flowcharts showing the processing procedure of the CPU. FIG. 5 is an explanatory diagram showing the structure of the detection range data area, and FIG. 6 is an explanatory diagram showing the relationship between the detection range and the detection signal. 10 ... Bed, 11 ... Table, 13 ... Spindle, 1
4, 16, 23 ... Servo motor, 15 ... Tailstock, 2
0 ... Tool rest, 30 ... Numerical control device, 50, 52, 5
4 ... Pulse generator, 51, 53, 54 ... Speed generator, 60 ... Sizing mechanism, 61 ... Sizing circuit,
62 ... Contactor, G ... Grinding wheel, W ... Workpiece, DT ...
… Data table, RA, RB… Detection range register

Claims (1)

[Scope of utility model registration request] 1. A numerical control of rotation of a spindle and feed of a tool,
In a spindle position detecting device for a numerically controlled grinding machine that processes a workpiece having a plurality of non-round portions, a sizing device that measures the outer shape of the non-round portion of the workpiece and outputs a measurement signal, the spindle Of main spindle rotation angle detecting means for detecting the current rotation angle position of, and data indicating the detection range of the rotation angle corresponding to the outer peripheral portion of the non-round portion to be measured by the sizing device,
Detection range storing means for storing the plurality of non-true circular portions in association with each other, and detection corresponding to the non-true circular portion to be processed from the data indicating the detection range stored in the detection range storing means. A detection range extracting means for extracting data indicating a range, and a rotation detected by the spindle rotation angle detecting means that the non-round portion being processed is at a rotation angle position to be measured by the sizing device. A rotational position of the spindle of the numerically controlled grinding machine, which is provided with a detection signal output means for detecting based on the angular position and the data indicating the detection range extracted by the detection range extraction means and outputting a detection signal. Detection device.