JPH0767669B2 - Automatic grindstone size measuring device in numerical control grinder - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a measuring device for automatically measuring the size and shape change of a grindstone, diameter, length, etc. in a numerically controlled grinding machine.

[Conventional technology]

Conventionally, as shown in Fig. 8, as a device for re-measurement of so-called dimensions such as diameter and length of a grindstone reduced by grinding of a workpiece, automatic touring, or automatic dressing in a numerically controlled grinder. By fixing the sensor 20 to the side of the table and moving the main spindle 21 from a predetermined position to bring the contact 20a of the touch sensor 20 into contact with the grindstone T, the diameter and length of the grindstone T are measured from the moving distance of the main spindle 21. Things are known.

As shown in FIG. 10, a contactor 22a provided at the tip of the lever 22 is provided on the peripheral surface of the rotating grindstone T as a device for measuring the change in the shape of the grindstone due to automatic replacement of the grindstone or the like. Touch it to measure the swing of the lever 22 around the pivot 23 as a displacement meter.
It is known that the amount of deformation of the grindstone T is measured by detecting with 24.

[Problems to be Solved by the Invention]

In the former dimension measuring device shown in FIG.
Although it is possible to measure the diameter and length only at points, if you try to measure changes in the shape of the grindstone by measuring at multiple points, as shown in FIG. ₁ ,
When moved to a portion of O ₄ other than O ₂ and O ₃ , the contact 20a of the touch sensor 20 interferes with the grindstone T, so that it is impossible to measure a shape change or the like.

Although the latter device in FIG. 10 can measure the change in shape of the grindstone T, the contactor 22 is attached to the peripheral surface of the rotating grindstone T.
Due to the contact with a, there is a problem that the contact 22a is heavily worn and the measurement accuracy is significantly reduced.

Furthermore, when it is necessary to measure the size and shape change of one grindstone, it is necessary to install the two devices shown in FIGS. 8 and 10 in the work area, which is not economical and the work area is narrow. There is an inconvenience.

The present invention is capable of efficiently measuring the diameter and length of the grindstone and measuring the shape change, etc. Moreover, there is almost no wear of the contactor, and the measurement can be performed with high accuracy, and the working area can be greatly narrowed. An object of the present invention is to provide an automatic grindstone size measuring device for a numerically controlled grinding machine.

[Means for Solving the Problems]

To achieve the above object, the present invention comprises a spindle on which a grindstone is mounted, and the spindle is configured to be moved by a drive motor in at least one of the X axis, the Y axis, and the Z axis. In a numerically controlled grinding machine, contact detection means for detecting contact of a grindstone mounted on the spindle and moving, and non-contact detection means for non-contact detection of grindstone moving toward the contact detection means. A spindle motor indexing means for indexing the grindstone mounted on the spindle to an arbitrary rotation angle; and a driving motor having a computing means for calculating the size of the grindstone from the position where contact is detected by the contact detection means. The reference point is controlled by controlling the spindle indexing means and moving the grindstone away from the contact detecting means during the second and subsequent measurements of the grindstone size with the detection position of the non-contact detecting means as the reference point. Ri was allowed folded from a position approaching the predetermined distance to the contact detection means is configured to have and a NC control device for contacting moved back to the contact detection means.

[Operation] When measuring the diameter and length of the grindstone, the grindstone is mounted on the main shaft and moved toward the contact detection means. The movement amount of the grindstone is calculated by the calculation means by the contact of the grindstone with the contact detection means. The calculating means calculates the subtraction of the calculated value from the reference distance between the spindle origin and the contact detecting means which is known in advance, and obtains the size of the grindstone.

Further, when measuring the amount of change in the shape of the grindstone, the NC controller uses the detection position of the non-contact detection means as a reference point and moves the grindstone away from the contact detection means during the second and subsequent measurements of the grindstone size, and moves from the reference point. The contact detecting means is folded back from a position approaching a predetermined distance, and again brought into contact with the contact detecting means.

〔Example〕

 The present invention will be described below with reference to the drawings.

1 and 2 show an embodiment of an automatic grindstone dimension measuring device of the present invention, in which A is a numerically controlled grinder (hereinafter, NC grinding) having an automatic tool changing device (not shown). It is called a board). This NC grinder A has the same basic structure as a so-called grinding center,
The grindstone T is taken out from a tool magazine (not shown) and mounted on the spindle 1, while the NC controller 2 controls the X-axis,
The Y-axis and Z-axis drive motors 3, 4, 5 are controlled respectively.

The automatic grindstone size measuring device of the present invention is applied to the NC grinder A, and moves toward the touch sensor (contact detection means) 6 for detecting the contact of the grindstone T and the touch sensor 6. A photoelectric sensor (contactless detection means) 6b for detecting the grindstone without contact, a servo amplifier (spindle indexing means) 7 for indexing the grindstone T at an arbitrary angle, and a detection signal to be described later based on the detection signal obtained by the touch sensor 6 will be described later. In addition to having a calculating means 8 for performing a predetermined calculation to obtain the diameter of the grindstone T and the like, the grindstone is moved away from the contact detecting means during the second and subsequent measurements of the grindstone size, and then contacts the contact detecting means again. It is composed of a moving NC device 2.

The touch sensor 6 has a contactor (tip sphere) 6a for detecting contact of the grindstone T, and a switch 6c for outputting a contact signal when the grindstone T touches the contactor 6a. The photoelectric sensor 6b is for contactlessly detecting that the grindstone T has approached the contact 6a to a predetermined position, and the signal output from the photoelectric sensor 6b is input to the signal processing unit 9 to be transmitted from the grindstone T. When the received light amount of the reflected light exceeds a set value, a contact signal is output from the signal processing unit 9 to the NC control device 2, and a detection signal output from the switch 6c of the touch sensor 6 is a signal processing unit. It is configured to be converted into a contact signal at 10 and guided to the NC control device 2.

Further, the servo amplifier 7 is an angle indexing circuit 7a that receives the indexing angle output from the NC control device 2 and a rotation start signal.
And an amplifier section 7b that receives a signal output from the angle indexing circuit 7a and sends a signal for rotation to the spindle motor 11.
And the number of pulses input from the NC control device 2 and the number of pulses output from the pulse coder 12 according to the rotation angle of the spindle 1 are compared in the angle indexing circuit 7a. Amplifier section 7b when the number of pulses matches
Is stopped and the rotation of the main shaft 1 is stopped.

The calculating means 8 is provided inside the NC control device 2 and, as shown in FIG. 2, an AND gate 8a for transmitting a feed pulse f and a Z-axis drive motor by the feed pulse f from the AND gate 8a. The interpolator 8b for generating an output pattern for controlling the servo device 5 and the position detection signal from the photoelectric sensor 6b or the contact signal from the switch 6c of the touch sensor 6 are input to the interpolator 8b.
Position Z when the grindstone T (or a reference block 14 described later) reaches a position separated from the contactor 6a by a certain distance from the counter inside the contactor 6a or when the grindstone T contacts the contactor 6a.
A CPU (center) that takes in (coordinate values on the Z-axis), stops the movement of the spindle 1 or the grindstone T in the Z-axis direction by turning off the AND gate 8a, and calculates the grindstone length based on the principle described later. An arithmetic processing unit) 8c and a storage device 8d connected to the CPU 8c. In this storage device 8d,
A control program for controlling the NC control device 2 and the above-mentioned devices for measuring the size of the grindstone is registered. When the spindle index is executed in the control program, CPU8c
The indexing angle from and the rotation start signal are sent to the servo amplifier 7. In FIG. 1, reference numeral 13 is an NC tape.

Next, the operation of the automatic grindstone size measuring device in the NC grinder of the present invention will be described.

FIGS. 3 and 4 explain the principle in the case of measuring the length of the grindstone T. The distance εZ in the Z-axis direction from the end surface 1a of the spindle 1 to the surface 14a perpendicular to the Z-axis. A reference block 14 of which ₀ is measured in advance is installed and placed on the spindle head 15.

Distance (reference distance) L between the end face 1a of the spindle 1 at the starting point and the contact 6a of the touch sensor 6 that outputs a contact signal
₀ is given by the following equation.

L ₀ = a ₀ + εZ ₀ (1) where a ₀ is the reference block 14 and the contactor of the touch sensor 6
It is the amount of axis movement that has occurred until the contact signal turns on when 6a is touched.

Next, the grindstone T is inserted into the spindle 1, and the contact of the touch sensor 6 is contacted.
Contact 6a. If the axial movement amount at this time is a, the grindstone length L _x of the grindstone T at the grindstone length L _x is given by the following equation.

L _x = L ₀ −a (2) When the measurement of the grindstone length L _x is completed, it is returned to the starting point separated from the touch sensor 6 by a small amount, and the spindle angle 1 is set for the starting angle set by the control program. Figure out. Perform the contact operation again and return to the starting point. Similarly, the indexing of the spindle 1 and the contact operation are repeated.

After the end of one contact operation, the whetstone length at each measurement position is calculated by the calculating means 8 and stored in the storage device 8d. The calculating means 8 obtains the maximum value L _max minimum value L _min ΔL = | L _max −L _min | for the plurality of measured grindstone lengths and compares it with the allowable value measured by the control program. If it exceeds the allowable value, an alarm is output. L
Register _max to the grindstone length offset of the NC controller.

Based on the above principle, the operation of the apparatus for measuring the grindstone length L _x by the control program in the storage device 8d will be described with reference to the flowcharts of FIGS. 5 to 7.

First, when the device is started and the measurement counter (not shown) is reset (step S1), the position at the starting point of the spindle 1 is stored in the storage device 8d of the calculating means 8 (step S2), and the reference distance sampling mode is set. It is determined whether or not (step S3).

In the reference distance sampling mode, the number of measurement points is set to "1" (step S4), the spindle 1 is moved in the Z axis direction by the operation of the Z axis drive motor 5, and the reference block 14 is moved to the left in FIG. Move at a high feed rate (step S6). Then,
The gate signal of the AND gate 8a of the arithmetic means 8 is turned on, and the feed pulse f enters the interpolator 8b through the AND gate 8a. The interpolator 8b outputs a control signal for the Z-axis drive motor 5 by this feed pulse f, and the Z-axis drive motor 5 continues to operate.

When the reference block 14 enters the detection area of the photoelectric sensor 6b (step S7), the photoelectric sensor 6b becomes the reference block.
An increase in the amount of light reflected from 14 is detected, and the signal is converted into a contact signal by the signal processing unit 9 and output to the CPU 8c of the calculating means 8.
to go into. When the CPU 8c detects this contact signal, the gate signal of the AND gate 8a is instantly turned off, the input of the feed pulse f to the interpolator 8b is stopped, and the Z-axis drive motor 5 is once stopped. Then, the calculation means 8 restarts the Z-axis drive motor 5 according to the control program registered in the storage device 8d, and before the contact 6a, for example, 2 mm (this distance 2 mm is
(Slightly larger than the maximum expected shape change of the grindstone)
The spindle 1 is moved at a high speed until it reaches (step S8). Since the distance between the contact 6a and the photoelectric sensor 6b is known, after the photoelectric sensor 6b detects the movement of the reference block 14, the reference block 14 will be in front of the contact 6a when the main shaft 1 is moved. Whether or not it reaches 2 mm is calculated in advance by the calculating means 8.

In the reference distance sampling mode (step S4), and when the number of measurement counters is less than the number of measurement points calculated in step S5 (step S9), the spindle 1 is not rotated and the 2 mm It moves toward the contact 6a at a slow feed rate (step S11). When the reference block 14 contacts the contact 6a of the touch sensor 6, the switch 6c outputs a contact signal, and the signal is detected by the signal processing unit 10 (step S12) and enters the CPU 8c of the computing means 8.

When this contact signal is input, the CPU 8c takes in the pulse number of the feed pulse f from the counter inside the interpolator 8b as the position of the reference block 14, and registers it in the storage device 8d (step S13), and at the same time, the AND gate 8a. The gate signal is turned off to stop the input of the feed pulse f to the interpolator 8b, and the Z-axis drive motor 5 is stopped.

When the contact position is stored in this way, the CPU 8c calculates the moving distance a ₀ from the starting point to the contact with the contact 6a (step S14). Here, it is again judged whether or not the reference distance sampling mode is selected (step S15). In the reference distance sampling mode, the CPU 8c calculates a ₀ + εZ ₀ to calculate the reference distance L ₀ (step S16),
The value is stored in the storage device 8d (step S17).

When the above memory is completed, the Z-axis drive motor 5 operates,
The reference block 14 is retracted 2 mm before the contact 6a (step S20), and the number of measurements is counted up by the counter (step S21).

When the step S9 is No, the spindle 1 is returned to the starting point by the operation of the Z-axis drive motor 5 (step S22), and it is judged whether or not it is the reference distance sampling mode (step S23).
In case of, it is the end.

If the reference distance sampling mode is not set in step S3, the number of measurement points is calculated from the start angle and the pitch angle by the calculating means 8 (step S5), and the grindstone T is taken out from the tool magazine and attached to the spindle 1. To be done. Thereafter, similarly to the above, the main shaft 1 is moved in the Z-axis direction by the operation of the Z-axis drive motor 5 to move the grindstone T leftward in FIGS. 1 and 4 at a high feed rate (step S6). Then, the gate signal of the AND gate 8a of the calculating means 8 is turned on, and the feed pulse f enters the interpolator 8b through the AND gate 8a. The interpolator 8b outputs a control signal for the Z-axis drive motor 5 by this feed pulse f, and the Z-axis drive motor 5 continues to operate. Then, when the grindstone T enters the detection area of the photoelectric sensor 6b (step S7), the photoelectric sensor 6b detects an increase in the amount of light reflected from the grindstone T, and the signal is the signal processing unit 9
Is converted into a contact signal and output to the CPU 8c of the calculating means 8. The computing means 8 controls the Z-axis drive motor 5 in accordance with the control program registered in the storage device 8d, and moves the spindle 1 at a high speed until it reaches 2 mm before the contact 6a (step S8). In step S9, when the amount of the measurement counter is less than the number of measurement points calculated in step S5, the NC controller 2 issues a command to the servo amplifier 7,
The spindle motor 11 rotates to index the grindstone T by a predetermined angle (step S10).

On the other hand, the CPU 8c will rotate the spindle 1 after the above detection signal is input.
When the grindstone T approaches the contact 6a at a high speed by 2 mm due to the continuous movement of, the rotation speed of the Z-axis drive motor 5 is reduced and the spindle 1 is moved in the Z-axis direction at a slow feed speed (step S1
1). Then, when the grindstone T contacts the contact 6a of the touch sensor 6, the switch 6c outputs a contact signal as in the case of the reference block 14, and the signal is detected by the signal processing unit 10 (step S12), and the calculating means. Enter the 8 CPU8c. CPU8c
When this contact signal is inputted, the number of feed pulses f from the counter inside the interpolator 8b is entered as the position of the grindstone T and registered in the storage position 8d (step S13). The gate signal is turned off, the input of the feed pulse f to the interpolator 8b is stopped, and the Z-axis drive motor 5 is stopped.

When the contact position of the grindstone T with respect to the contactor 6a is stored in this way, the CPU 8c calculates the moving distance a from the starting point until the contactor contacts the contactor 6a (step S14). It is determined whether or not the reference distance sampling mode is selected (step S15). If the reference distance sampling mode is not set, the CPU 8c calculates Lo-a to calculate the grindstone length L _x (step S18), and the grindstone length is stored in the storage device. It is stored in 8d (step S19). When the above memory is completed, the whetstone T is retracted to 2 mm before the contact 6a by the operation of the Z-axis drive motor 5 (step S
20), the number of measurements is counted up in the counter (step S21).

The above-mentioned operation is repeated until the number of measurement points defined by the measurement number counter matches, and if this matches,
When the result in S9 is NO, the spindle 1 is returned to the starting point (step S22). Further, it is determined whether the reference distance sampling mode is selected (step S23), and if No, the maximum value (L _max ) and the minimum value (L _min ) of the grindstone length measured and stored above are calculated (step S24). , The variation amount is calculated (step S25).

It is examined whether the variation amount is within the allowable value set in the control program (step S26), and if it is within the allowable value, the maximum value is registered in the tool offset of the NC control device 2 (step S27). If the allowable value is exceeded, an alarm signal is output (step S2
8) Finish.

In the above, the grindstone T is moved by moving it in the Z-axis direction.
Although the length of the grindstone has been described, the diameter of the grindstone can be measured by moving the grindstone in the X-axis direction (direction perpendicular to the paper surface in FIG. 1) or the Y-axis direction (vertical direction). In this case, it goes without saying that the touch sensor 6 is rearranged in the moving direction of the grindstone. Further, the NC control device 2 uses the detection position of the grindstone T by the photoelectric sensor 6b as a reference point, and fast-forwards the grindstone T to a position (a position 2 mm before the contact 6a) which is close to the touch sensor 6 by a predetermined distance from the reference point. After that, the grinding wheel T is switched to the low-speed feed, and the grinding stone T which moves away from the touch sensor 6 at the time of the second and subsequent measurement of the grinding wheel size is folded back at the above position and moved toward the touch sensor 6 again, but this is the fast feeding. This is because the switching point for low-speed feed and the turning point of the grindstone are brought as close as possible to the touch sensor 6 so that the dimension measurement work can be performed efficiently, and is not limited to 2 mm. Furthermore, in the above embodiment, the photoelectric sensor 6b
When the position detection signal is output from, the movement of the spindle 1 in the Z-axis direction is temporarily stopped, but the movement may be continued without stopping the spindle 1.

〔The invention's effect〕

As described above, the present invention is provided with a spindle on which a grindstone is mounted, and the spindle is configured to be moved by a drive motor in at least one of the X axis, the Y axis, and the Z axis. In the grinding machine, contact detection means for detecting the contact of the grindstone which is mounted on the spindle and moved, non-contact detection means for contactlessly detecting the grindstone moving toward the contact detection means, It has a spindle indexing means for indexing the grindstone mounted on the spindle to an arbitrary rotation angle, and a computing means for calculating the size of the grindstone from the position where the contact is detected by the contact detecting means. The grinding means is controlled and the grindstone is moved away from the contact detection means during the second and subsequent measurements of the grindstone dimension with the detection position of the non-contact detection means as a reference point, and the grindstone is moved from the reference point to the above-mentioned point. Since the touch sensing means so folded back from a predetermined distance closer position there is a structure in which and a NC control device for contacting moved back to the contact detection means,
The following effects are obtained.

(A) It is possible to measure the amount of variation and the diameter or length without interference such as interference with the contact of the touch sensor and wear of the contact. That is, at the measured positions of a plurality of points, the amount of variation is obtained from their maximum difference, and from the distance to the position farthest from the spindle end or the spindle center, the actual length in the state of being attached to the spindle,
Alternatively, the diameter can be obtained.

(B) In the past, in order to measure the diameter and length dimensions and runout, it was necessary to install two devices in the grinding work area as described above, but in the present invention, the small size is used. Since the contact detecting means and the non-contact detecting means, which are the parts, need only be arranged in the work area, the work area is expanded.

(C) Since it is possible to know the positions of a plurality of points, there is a function of automatically checking for abnormalities of the grindstone, such as a part of the grindstone falling or deforming, for example, a constant threshold value for the variation amount. It is easy to add a function such as issuing an alarm when the number is exceeded.

(D) After the reference point is set by the non-contact detecting means,
Since the turning-back position of the grindstone is determined, regardless of the size of the length and diameter of the whetstone, the turning-back position can be set closest to the contact detection means accurately considering only the expected maximum deformation amount thereof. By utilizing the turn-back position as a switching point for low-speed feed, the grindstone can be fed at high speed from the first measurement to the position closest to the contact detection means, and the measurement work can be performed efficiently.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of an automatic grindstone size measuring device in a numerically controlled grinding machine according to the present invention, FIG. 2 is a block diagram showing an example of arithmetic means, and FIGS. 3 and 4 are Explanatory diagrams for explaining the measurement principle of dimensions, FIGS. 5 to 7
The figure is a flow chart of the present invention. FIG. 8 is a side view of a conventional dimension measuring device, FIG. 9 is a front view of the same, and FIG. 10 is a side view of a conventional measuring device for measuring changes in shape and the like. T: Grindstone, 1 ... Spindle, 3,4,5 ... Drive motor, 6 ...
... Touch sensor (contact detection means), 7 ... Servo amplifier (spindle indexing means), 8 ... Calculation means.

Claims (1)

[Claims] 1. A spindle (1) on which a grindstone (T) is mounted, the spindle (1) being a drive motor (3,4,5) in at least one direction of an X-axis, a Y-axis and a Z-axis. In a numerically controlled grinding machine configured to be moved by a contact detecting means (6) for detecting the contact of a grindstone (T) mounted on the spindle (1) and moving, and the contact detecting means (6). ), A non-contact detecting means (6b) for detecting the grindstone (T) moving closer to the main shaft without contact, and a spindle for indexing the grindstone (T) mounted on the spindle (1) at an arbitrary rotation angle. The drive motors (3,4,5) having indexing means (7) and calculating means (8) for calculating the size of the grindstone (T) from the position where the contact is detected by the contact detecting means (6). And the spindle indexing means (7) is controlled and the detection position of the non-contact detecting means (6b) is used as a reference. During the second and subsequent measurements of the grindstone size, the grindstone (T) is moved away from the contact detection means (6) and folded back from a position closer to the contact detection means (6) by a predetermined distance from the reference point to make the contact. An automatic grindstone size measuring device for a numerical control grinding machine, comprising an NC control device (2) for moving the detection means (6) again.