JPH05203441A - Female thread measuring apparatus - Google Patents

Abstract

(57) [Summary] [Purpose] By determining the shape of the female screw based on the electrical detection result without relying on the sense of the measurer, it is possible to prevent variation in the measure result due to the skill and situation of the measurer and improve measurement accuracy. The purpose is to increase and quantitatively and highly accurately measure various dimensions of the internal thread. A distance sensor 12 provided in the sensor holder 11 for measuring a distance between a predetermined portion of the sensor holder inserted in the screw hole and an inner wall of the screw hole in a non-contact manner, and a sensor holder 11
NC machine tool 13 that outputs the insertion depth of the sensor holder into the screw hole and the distance sensor 12 with the sensor holder 11 inserted into the screw hole.
And an arithmetic processing unit 17 for outputting the internal thread shape in the screw hole based on an output signal indicating the distance from the inner wall of the screw hole output by NC machine and an output signal indicating the insertion depth of sensor holder 11 output by NC machine tool 13. It is equipped with.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a female screw measuring device for automatically measuring various dimensions of a female screw formed on the inner wall of a screw hole.

[0002]

2. Description of the Related Art Conventionally, as a method for measuring a female screw formed on the inner wall of a screw hole, as shown in FIG. 19, for example, a detector 2 having a lateral protrusion 2a made of a spring material is provided at an end of a handle 1. There is a method of mounting and using an inspection tool 4 provided with a score line 3 at a position corresponding to a predetermined tap depth from the tip of the detector 2. In this method, a measurer holds the handle 1 by hand to detect. Insert the child 2 into the screw hole 5 until it bottoms out, push the handle 2 little by little while pressing the protrusion 2a against the inner wall of the lower hole portion 5a of the screw hole 5, and the protrusion 2a is the screw at the bottom end of the female screw 6. When the contact with the crest 6a is perceived by hand, the positional relationship between the upper end 5b of the screw hole 5 and the score line 3 is visually checked to determine whether the tap depth of the female screw is within the reference.

Another conventional method for measuring an internal thread formed on the inner wall of a screw hole is, as shown in, for example, FIG. 20 (a), a male thread which can be screwed into the female thread to be measured at the end of the handle 1. A detector 7 having a portion 7a is attached, and a score line 3 is provided at a position corresponding to a predetermined tap depth from the tip of the detector 7.
There is a method of using the inspection instrument 8 provided with the. In this method, the measurer holds the handle 1 by hand and screw the detector 7 into the screw hole 5 as shown in FIG. When it is perceived that the tip of the portion 7a has reached the lowest thread 6a of the female screw 6, the positional relationship between the upper end 5b of the screw hole 5 and the score line 3 is visually confirmed, and the tap depth of the female screw is checked. Is within the standard.

[0004]

However, in any of the above-described conventional female screw measuring methods, the operator senses that the detectors 2 and 7 are at the lowermost end of the female screw 6 by the feel of the hand, and further visually. Since the tap depth of the internal thread is determined from the result of confirming the positional relationship between the upper end 5b of the screw hole 5 and the score line 3, the position where force is applied is varied depending on the skill and situation of the measurer. However, there is a problem in that the measurement results vary, and various dimensions of the female screw cannot be quantitatively grasped because only the positional relationship between the upper end 5b of the hole 5 and the score line 3 is determined. And parable line 3
Even if a dimensional scale is provided instead of, there is a problem that the dimensional accuracy that can be visually read becomes extremely rough.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a female screw measuring device that advantageously solves the problems of the conventional method as described above.
The female screw measuring device according to the invention is provided in a sensor holder,
A distance sensor that measures the distance between a predetermined portion of the sensor holder inserted into the screw hole and the inner wall of the screw hole in a non-contact manner, and the sensor holder is inserted into the screw hole and into the screw hole. Sensor holder inserting means for outputting the insertion depth of the sensor holder, and the distance sensor outputs in a state where the sensor holder is inserted into the screw hole,
Female screw shape output means for outputting the shape of the female screw in the screw hole based on an output signal indicating the distance to the inner wall of the screw hole and an output signal indicating the insertion depth of the sensor holder output by the sensor holder inserting means. And ,.

In the female screw measuring device according to the second invention of the present application, a probe having a base portion pivotally supported by a probe holder inserted into a screw hole and projecting laterally from the probe holder, and the probe holder are provided. A probe holder advancing / retreating means for advancing / retreating to an arbitrary position in the protruding direction of the probe and outputting the position of the tip end of the probe in the advancing / retreating direction, and detecting contact between the inner wall of the screw hole and the tip of the probe. Probe contact detection means for
While inserting the probe holder into the screw hole, the probe holder insertion means for outputting the insertion depth of the probe holder into the screw hole, and the probe contact detection means output, the inner wall of the screw hole and the probe An output signal indicating the contact with the tip, an output signal output by the probe holder advancing / retreating moving means and indicating the position of the tip of the probe in the advancing / retreating direction, and an insertion depth of the probe holder output by the probe holder inserting means. And a female thread shape output means for outputting the shape of the female thread in the screw hole based on a signal indicating the height.

The female screw measuring device according to the third invention of the present application has a probe holder which is inserted into a screw hole.
A probe that is supported so as to be able to project laterally from the probe holder and that has a tip portion that can be tightly fitted in the thread groove of the female screw in the screw hole, and that causes the probe to project and retract with respect to the probe holder. A probe advancing / retreating moving means, a probe contact state detecting means for detecting a contact state between the inner wall of the screw hole and the tip portion of the probe, and the probe holder inserted into the screw hole, and into the screw hole. An output signal output by the probe holder insertion means that outputs the insertion depth of the holder and output by the probe contact state detection means, which indicates the contact state between the inner wall of the screw hole and the tip of the probe, and the probe holder insertion means outputs the output signal. Female thread shape output means for outputting the shape of the female thread in the screw hole based on a signal indicating the insertion depth of the probe holder. , It is made of comprises a.

[0008]

In the female screw measuring device of the first invention,
The sensor holder inserting means inserts the sensor holder into the screw hole to be measured and outputs a signal indicating the insertion depth of the sensor holder into the screw hole, and at the same time, the sensor holder insertion device is installed sideways on the sensor holder. The non-contact type distance sensor outputs a signal indicating the distance to the inner wall of the screw hole when inserted into the screw hole, and the female screw shape output means outputs the shape of the female screw in the screw hole based on the output signals. Is output.

In the female screw measuring device according to the second aspect of the invention, the probe holder inserting means inserts the probe holder into the screw hole to be measured and at the same time inserts the probe holder into the screw hole. The probe holder advancing / retracting moving means moves the probe holder, which in turn supports the probe holder and laterally projects the probe protruding laterally to an arbitrary position in the projecting direction, while advancing and retracting the tip of the probe. When the probe contact detection means detects the contact between the inner wall of the screw hole and the tip of the probe, the probe contact detection means outputs a signal notifying that, and the female screw shape output means outputs the screw hole based on those output signals. Output the shape of the female screw inside.

In the female thread measuring device according to the third aspect of the invention, the probe holder inserting means inserts the probe holder into the screw hole to be measured, and at the same time, inserts the probe holder into the screw hole. The probe holder advancing / retreating moving means outputs a signal indicating that the probe holder has a tip having a shape capable of being closely fitted to the thread groove of the female screw in the screw hole, which is laterally supported by the probe holder. The probe contact state detecting means detects the contact state between the inner wall of the screw hole and the tip of the probe and outputs a signal, and the female screw shape output means outputs the output signal. The shape of the female screw in the screw hole is output based on

Therefore, in any of the above-mentioned first to third inventions, the shape of the female screw is obtained based on the electrical detection result without depending on the sense of the measurer. The measurement result does not vary according to the above, and the measurement accuracy can be improved. Further, since the shape of the female screw is obtained using a non-contact type distance sensor or a contact probe, various dimensions of the female screw can be quantitatively and highly accurately measured.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of the female thread measuring device of the first invention, and 11 in the figure shows a rod-shaped sensor holder that can be inserted into a screw hole to be measured, Three eddy current type distance sensors 12 as non-contact type distance sensors are laterally embedded in the lower portion of the sensor holder 11 so as to be arranged at predetermined intervals in the longitudinal direction of the sensor holder. The upper end portion of the sensor holder 11 is concentrically fixed to a shank (not shown), and the shank has x, y, z of a normal NC machine tool 13 as a sensor holder insertion means as shown in FIG. It is attached to a spindle end that can be moved to arbitrary positions in three directions. Here, the sensor holder 11 is fixed at a predetermined position on the work table 14 by moving the spindle end of the NC machine tool 13. It can be moved with respect to the work 15 and inserted into the screw hole 5 to be measured formed in the work 15.

Here, each of the distance sensors 12 outputs a voltage that rises in proportion to an increase in the distance between the distance sensor 12 and the object to be measured in front of the distance sensor 12, and those output voltages are connected to the shank. Via the so-called quick change type rotary connector, which are respectively input to and amplified by three amplifiers 16 installed in a fixed place, and the output signals of those amplifiers 16 are added together. ,
It is input to an arithmetic processing unit 17 having a normal microcomputer as female screw shape output means, and the arithmetic processing unit 17 outputs the spindle end position and thus the tip of the sensor holder 11 output by the controller of the NC machine tool 13. A signal indicating the position is also input, and the arithmetic processing unit 17 performs arithmetic processing described later based on the input signal and outputs the result to a normal display device 18, and the display device 18 displays it on the screen.

The controller of the NC machine tool 13 includes:
When the data of the height, depth and horizontal position of the screw hole 5 to be measured of the work 15 on the work table 14 is given, the NC machine tool 13 moves the spindle end based on the data, and the sensor After the holder 11 is positioned above the screw hole 5 and slowly lowered, the holder 11 is inserted into the screw hole 5 just before it bottoms out, and then a predetermined measurement operation is performed.
A control program is given.

In such a screw hole measuring device, when the NC machine tool 13 inserts the sensor holder 11 into the screw hole 5 and slowly lowers it according to the control program, as shown in FIG. 3 (a). In addition, the three distance sensors 12 all detect the thread 6a of the complete thread portion A of the female thread 6, and
As shown in (b), the thread 6a of the incomplete thread portion B of the female screw 6 is sequentially detected from the distance sensor 12 at the lowermost end, and then three distance sensors are detected as shown in FIG. 3 (c). All 12 detect the pilot hole 5a, and as a result, the output voltages of the three distance sensors 12 from the three amplifiers 16 are added to the arithmetic processing unit 17 as shown in FIG. Signal is input.

In FIG. 4, at the position where the feed displacement for lowering the sensor holder 11 is a, the lowermost distance sensor 12 of the three distance sensors 12 is the thread 6a of the complete thread portion A of the female screw 6.
In the range where the feed displacement is b, the three distance sensors 12 sequentially detect the threads 6a of the complete thread portion A of the female screw 6, and the feed displacement is c. The position indicates the time when the detection of the screw thread 6a of the complete thread portion A by all three distance sensors 12 has started. In the range of the feed displacement d, all the three distance sensors 12 have the complete thread portion A. Screw thread
6a is detected, and the feed displacement is e,
The distance sensor 12 at the lowermost end of the three distance sensors 12 indicates the time when the screw thread 6a of the incomplete thread portion B of the female screw 6 starts to be detected. The range of the feed displacement f is three distance sensors 12 Shows the state in which the thread 6a and the pilot hole 5a of the incomplete screw portion B are sequentially detected, and at the position where the feed displacement is g, the detection of the pilot hole 5a by all three distance sensors 12 starts. In the range where the feed displacement is h, the three distance sensors 12 are all detecting the pilot hole 5a. Also,
The maximum value of the added voltage value corresponds to the root diameter of the complete screw portion A of the female screw 6, and the minimum value of the added voltage value corresponds to the peak diameter of the complete screw portion A of the internal screw 6.

Therefore, the arithmetic processing unit 17 performs arithmetic processing based on the relationship of the position in the height direction of the distance sensor 12 at the lowermost end with respect to the lower end position of the sensor holder 11, which is given in advance, and From the lower end position of the sensor holder 11 output by the control device of the NC machine tool 13 at the position where the feed displacement in the change is a, the position in the height direction of the distance sensor 12 at the lowest end at that time, that is, the complete screw part The height direction of the distance sensor 12 at the lowest end at that time from the lower end position of the sensor holder 11 output by the control device of the NC machine tool 13 at the position where the feed displacement is e is obtained while the starting position of A is obtained. The position, that is, the starting position of the incomplete thread portion B is obtained, and the tap depth which is the feed displacement between them is obtained.

Further, the arithmetic processing unit 17 is a device of several kinds of screw holes whose peak and valley diameters are measured with high accuracy by using, for example, a magnifying projector for a section after the measurement by the device. The comparison data of the added output voltage of the amplifier and its high-accuracy measurement value is given in advance, and the arithmetic processing is performed based on the comparison data, and the maximum value of the change in the input voltage While obtaining the root diameter of the complete screw portion A of the female screw 6 of the screw hole 5,
From the minimum value in the change of the voltage, the screw hole 5
The ridge diameter of the complete thread portion A of the female screw 6 is calculated.

Therefore, according to the female screw measuring device of this embodiment, the shape of the female screw 6 is obtained based on the electrical detection result without depending on the sense of the measurer. Therefore, depending on the skill and situation of the measurer. The measurement result does not vary and the measurement accuracy can be improved. Moreover, since the shape of the internal thread 6 is obtained using the non-contact type eddy current type distance sensor 12, the tap depth, the root diameter and the peak diameter of the internal thread 6 can be quantitatively and highly accurately measured. it can.

In particular, in the apparatus of this embodiment, the output voltages of the three distance sensors 12 are added and used to simultaneously detect the distance for the depth of the female screw 6 within a certain range. When foreign matter such as chips adheres to the complete thread of the sensor holder, it is possible to prevent erroneous detection of an incomplete thread that is likely to occur with only one sensor. Rotate 11 around its axis,
If the distance in several directions with respect to the female screw 6 is obtained, the female screw 6
The position of the center of can also be obtained with high accuracy. It should be noted that the number of distance sensors in the present invention may be one or more, and is not limited to three in the above example. The non-contact type distance sensor may be, for example, an optical distance sensor using laser light. In this case, an optical distance sensor is provided at the base of the sensor holder and a reflecting mirror is provided obliquely at the tip of the sensor holder. The lateral distance may be measured.

FIG. 5 is a block diagram showing an embodiment of the female screw measuring device of the second invention, in which 21 is a probe and 22 is a probe.
Is a disk-shaped probe holder that pivotally supports the base of the probe 21 and has a size that can be sufficiently inserted into the screw hole to be measured, 23 is an arm that supports the probe holder 21, and 24 is the arm 23. The probe holder advancing / retreating mechanism as a probe holder advancing / retreating moving means which supports is each shown.

Probe holder advance / retreat moving mechanism here
To describe based on the posture shown in FIG. 5, 24 is a cylindrical base 25 having an axis line extending in the up-down direction and having a cylindrical shape as shown in FIG. 6, and laterally fixed to the lower end thereof. Figure 7
A square frame-shaped bracket 26 is provided as shown in the cross section, and a driven gear 28 is rotatably supported by a bearing 27 in a central hole of a base 25 of the base 25. A motor 29 is mounted, the driven gear 28 meshes with a drive pinion 30 provided on the output shaft of the servo motor 29, and a ball circulation type nut 31 is fixed concentrically to the center of the driven gear 28. The ball screw shaft 32 is screwed into the nut 31, and the spline shaft 33 integrally provided at the lower end of the ball screw shaft 32 is a ball circulation type spline holder fixed to the upper portion of the bracket 26. To 34,
It is fitted so that it can be lifted and lowered at the same time as its rotation is restricted.

On the other hand, a guide rail 35 is horizontally fixed to the lower portion of the bracket 26, and a ball circulating slider 36 is movably fitted to the guide rail 35, and the slider 36 moves to the slider 36. The block 37 is fixed, and the arm 23 is fixed to one end of the moving block 37. Further, pins 38 serving as cam followers project on both sides of the moving block 37, while at the lower end of the spline shaft 33, long holes inclined at the same angle to the axial direction of the ball screw shaft 32 are provided on both sides. A U-shaped cam member 39 formed with 39a is fixed so as to straddle the moving block 37, and the pins 38 are substantially free of play in the elongated holes 39a and the longitudinal direction of the elongated hole 39a. It is fitted so that it can slide in any direction.

In the probe holder advancing / retreating mechanism 24, when the servo motor 29 rotates its output shaft in a predetermined direction by a predetermined amount, the rotation is transmitted to the nut 31 via the drive pinion 30 and the driven gear 28. As a result, the nut 31 rotates in a predetermined direction, and the ball screw shaft 32 whose rotation is restricted by the fitting of the spline shaft 33 and the spline holder 34.
When the servo motor 29 rotates its output shaft by a predetermined amount in a direction opposite to the predetermined direction, the ball screw shaft 32 similarly descends by a predetermined distance. Then, as the ball screw shaft 32 is moved up and down, as shown in FIGS. 8A and 8B, the movement block 37 is moved in the horizontal direction by fitting the long hole 39a of the cam member 39 and the pin 38. Converted,
As a result, the moving block 37 supports the probe holder 22 via the arm 23 while being guided by the guide rail 35,
The ball screw shaft 32 is horizontally moved by a distance corresponding to the ascending / descending distance.

A rotary encoder 40 is also provided on the servo motor 29, and the rotary encoder 40 outputs the rotation amount of the output shaft of the servo motor 29 by a pulse signal. Therefore, according to this probe holder advancing / retreating mechanism 24, the probe holder is moved based on the operation of the servo motor 29.
In the posture shown in the drawing, 22 can be moved forward and backward in the horizontal direction by an arbitrary distance, and the current position of the probe holder 22 can be output as an output signal of the rotary encoder 40.

The probe holder advance / retreat moving mechanism 24 further includes
A cylindrical cover 41 fixed to the lower end of the base 25 and covering the bracket 26, and a conical shank fixed to the upper end of the base 25 to cover the servomotor 29 and the ball screw shaft 32.
42 and the shank 42 is, for example, B of the MAS standard.
It is shaped and sized to match the T shank, and can be moved to any position in the three directions x, y, z of a normal NC machine tool as the probe holder insertion means, for example, similar to that shown in FIG. It is attached to the main spindle end, and here, by moving the main spindle end of the NC machine tool, the probe holder advancing / retreating moving mechanism 24 and thus the probe holder 22 are attached.
Can be moved with respect to the workpiece fixed at a predetermined position on the workpiece table and inserted into the screw hole of the measurement object formed in the workpiece.

By the way, the probe 21 is, for example, as shown in FIG.
As shown in (a), a spherical contact portion 21a is formed at its tip, and its base is supported by the side of the probe holder 22 via a support shaft 43, as shown by the phantom line in the figure. It is swingable in the vertical direction. Also probe 21
Is a flexible contact support 21b extending rearward from its base.
Is urged by a spring 44 from above and below, and in a free state where external force is not applied to the contact portion 21a, it is located at the neutral position shown by the solid line in the figure, and a movable contact 45 is provided at the end of the contact support portion 21b. On the other hand, in the probe holder 22, the movable contact of the probe 21 is located in the neutral position.
Fixed contacts 46 are provided in electrical isolation with respect to the probe holder 22 so as to mechanically contact 45. Therefore, the movable contact 45 is separated from the fixed contact 46 as shown by a phantom line in the figure when the probe 21 swings upward or downward by a predetermined amount or more due to the contact between the contact portion 21a and the work, and as a result, The electrical connection between the two will also be cut off. Further, here, the electrical conduction due to the contact between the probe 21 and the workpiece having the screw hole to be measured is also detected through a separate circuit.

Then, a signal indicating electrical conduction due to contact between the probe 21 and the work and the movable contact 45.
As shown in FIG. 5, the signal indicating the electrical continuity between the fixed contact 46 and the fixed contact 46 is output from the rotary encoder 40 together with a so-called quick change type rotary connector (not shown) attached to the base 25. Via, as a female screw shape output means installed in a fixed place,
The control signal that is input to and output from the arithmetic processing unit 47 that includes a normal microcomputer and a normal servo controller separate from it is
It is supplied to the servomotor 29 via the connector. Further, a signal indicating the position of the spindle end position and thus the position of the probe holder advancing / retreating mechanism 24, which is output from the controller of the NC machine tool, is also input to the arithmetic processing unit 47, and the arithmetic processing unit 47 controls the NC machine tool. The operation of the probe holder advancing / retreating movement mechanism 24 is controlled through the servo controller in cooperation with the device, the arithmetic processing is performed based on each of the input signals, and the result is output to the normal display device 48, and the display device 48. Will display it on the screen.

Here, when data of the upper end height, depth and horizontal position of the screw hole to be measured of the work on the work table is given to the controller of the NC machine tool, based on these data. A control program is provided so that the NC machine tool moves a spindle end to perform a predetermined measurement operation described later, and the arithmetic processing unit 47 has
When the NC machine tool performs the measuring operation, the probe holder advancing / retreating mechanism 24 moves the probe holder 22 forward until the probe 21 contacts the workpiece, and after the contact, retracts the probe holder 22 from the contact position by a predetermined minute distance. A control program is provided to perform an oscillating operation in which the probe holder 22 is moved forward until the probe 21 contacts the work again.

After the contact with the work, the probe 21
As the probe further advances, the probe 21 swings upward or downward, and the electrical connection between the moving contact 45 and the fixed contact 46 is cut off. Therefore, in this device, during the oscillation operation, even if the probe 21 goes too far due to the inertia of the mechanism or the like, a signal indicating the electrical continuity between the probe 21 and the work and the movable contact 45 are fixed. From the time when both the signal indicating the electrical conduction with the contact 46 and the time when the contact with the workpiece in the neutral state of the probe 21 is accurately obtained, the probe holder advancing / retreating mechanism 24 at the contact time. The position of the work surface is obtained based on the position and the position of the contact portion 21a of the probe 21 with respect to the probe holder advancing / retreating mechanism 24.

In such a screw hole measuring device, the screw hole is measured according to the control program as shown in FIG. In the figure, the black circles indicate the contact portions 21a of the probe 21 that are in contact with the work 15, and the white circles indicate the contact portions 21a of the probe 21 that are not in contact with the work 15. That is, here, first, the NC machine tool slightly moves the probe holder advancing / retreating mechanism 24 and then the probe holder 22 at a predetermined retracted position with respect to the probe holder advancing / retreating mechanism 24 from above the screw hole to be measured in the radial direction. After offsetting the position and slowly lowering it, as shown in FIG. 10 (a), when the contact portion 21a of the probe 21 comes into contact with the end surface 15a of the work 15 around the screw hole 5, the probe 21 is moved to that end surface. Moving mechanism to move the probe holder back and forth until it is separated from 15a
The position of the upper end 5b of the screw hole 5 is accurately detected by the probe 21 by moving 24 inward of the screw hole 5.

Next, here, as shown in FIG.
While the probe holder advancing / retreating movement mechanism 24 performs the oscillation operation, the NC machine tool lowers the probe holder advancing / retreating movement mechanism 24 to slowly lower the probe holder 22 into the screw hole 5, and thereby the probe holder 22. While changing the height of the holder 22, the screw hole 5
The contact position of the probe 21 with respect to the screw thread 6a of the internal screw 6 therein is sequentially detected, and the arithmetic processing unit 47 sequentially finds the shape of the internal screw 6 based on the contact position.

In the arithmetic processing unit 47, as shown in FIG. 10 (c), the probe 21 has the prepared hole 5a based on the obtained shape.
When it is detected that the bottom of the hole has been reached, the probe holder advancing / retreating mechanism 24 is caused to stop the oscillation operation,
Next, the shape of the female screw 6 thus obtained is given to the controller of the NC machine tool, and the contact portion 21a of the probe 21 traces the root of the female screw 6 based on the shape of the female screw 6 as shown in FIG. 10 (d). , NC machine tool, while moving the probe holder advancing / retreating mechanism 24 spirally, the upper end 5b of the screw hole 5
It is detected that the contact between the contact portion 21a of the probe 21 and the workpiece 15 is maintained, and it is confirmed that the shape of the female screw 6 can be accurately measured.

Therefore, according to the female screw measuring device of this embodiment, the shape of the female screw 6 is obtained based on the electrical detection result without depending on the sense of the measurer, so that the measurer's skill level and situation can be used. The measurement result does not vary and the measurement accuracy can be improved. Further, since the shape of the internal thread 6 is obtained by using the contact type probe 22, the tap depth of the internal thread 6, the root diameter and the peak diameter, the hole position of the screw hole 5, the hole diameter of the lower hole portion 5a and The depth, the peak shape of the female screw 6, the pitch, the inclination, and the like can be quantitatively and highly accurately measured by one measurement operation.

Further, according to the apparatus of this embodiment, the size obtained by adding the length of the probe 21 protruding from the outer diameter of the probe holder 22 and a slight margin is set as the minimum diameter, and one apparatus can be used for various types. Since it is possible to measure the diameter and the screw holes of various kinds of pitches, it is possible to obtain extremely high versatility.

The rocking of the probe 21 due to the contact with the work piece, as shown in FIG. 9B, instead of providing the movable contact 45 and the fixed contact 46 in the probe holder 22,
T from the base of the probe 21 supported by the support shaft 43 to the rear side.
Extend the arm 21c in the shape of a letter, and place two piezoelectric elements 49 in the probe holder 22 so that the end of the arm 21c is sandwiched from above and below, and detect based on the change in the output voltage of those piezoelectric elements 49. You can

FIG. 11 is a block diagram showing an embodiment of the internal thread measuring device of the third invention, and FIG. 12 is an enlarged sectional view showing the tip of the probe holder of the internal thread measuring device.
In the figure, 51 indicates a rod-shaped probe holder having a thickness that can be inserted into the screw hole 5 to be measured, and 52 indicates a rod-shaped probe, respectively.
As shown in (a) and (b), a conical tip portion 52a having an apex angle corresponding to the angle of the screw thread is formed so that the screw groove of the female screw 6 in the screw hole 5 can be closely fitted. The probe holder 51 is supported movably in the radial direction of the probe holder 51 by an annular bush 53 provided laterally inside the tip portion (lower end portion in FIG. 11) of the probe holder 51, and in the circumferential direction of the outer peripheral surface. Rotation around its own axis is regulated by sliding contact between a flat portion (not shown) formed in part and the flat portion of the probe holder 51, and the tip portion 52a of the probe 52 is restricted.
On the outer peripheral surface of each of the air outlets, which open in the axial direction of the probe holder 51 (upward and downward in FIG. 11).
54 is formed, and the base of the probe 52 is integrally coupled with a piston 56 of an air cylinder 55 as a probe advancing / retreating means formed laterally in the tip of the probe holder 51, and the probe 52 A seal ring 57 for maintaining airtightness is inserted between the outer peripheral surface of the probe holder 51 and the probe holder 51.

Then, the probe 52 and the piston 56
An air passage 58 is formed in the center of the air passage 58. One end of the air passage 58 opens at the air outlet 54, and the other end of the piston 56 faces the head side end face of the piston 52. To open the head side air chamber 59 of the air cylinder 55 and the air outlet 54 to communicate with each other.
52 is a spring provided in the head side air chamber 59
60, through the piston 56, the tip 52a is the internal thread 6
With a pressing force that does not damage the screw thread 6a of the, the forward bias is always urged in the protruding direction.

On the other hand, the base portion (upper end portion in FIG. 11) of the probe holder 51 here is concentrically fixed to a shank 62 via a support shaft 61, and the shank 62 has a shape and a shape matching a BT shank of the MAS standard, for example. It is attached to the main spindle end of a normal three-axis control type machining center 63 as a probe holder insertion means. Here, a work table (not shown) is attached to the main spindle end of the machining center 63, x, y, By moving to any position in the three directions of z (in FIG. 11, the y direction is a direction perpendicular to the paper surface),
By moving the probe holder 51 relative to the work 15 fixed at a predetermined position on the work table,
It can be inserted into the screw hole 5 to be measured formed in 15.

Further, inside the support shaft 61 and the probe holder 51, two air passages 64 and 65 are formed so as to extend in the axial direction thereof, and one end portion of the air passage 64 is The air cylinder 55 communicates with the head-side air chamber 58, and one end of the air passage 65 has the air cylinder 55.
Of the head side air chamber 58 communicates with a rod side air chamber 66 defined on the opposite side of the piston 56. The other end of the air passage 64 has a rotary type pneumatic joint 67 which is opened in the intermediate portion of the support shaft 61, is fitted in the intermediate portion, and is detachably attached to the fixed portion of the machining center 63. Through the 5-port 2-position solenoid switch valve 68 port e
To the circuit 69 leading to the air passage 65
The other end of the five-port electromagnetic switching valve 68 is opened at the end of the support shaft 61 and passes through the air passage in the center of the shank 62.
It communicates with the circuit 70 connected to port d.

Here, the electromagnetic switching valve 68 has a port a and a port d when the valve body is in the normal position.
In addition, port b is connected to port e and port c is closed, while port b is set to port d and port c is set to port e when the valve body is in the operating position due to the excitation of the electromagnetic solenoid. The ports a are closed and the port a is closed. An exhaust silencer 71 is connected to the port b of the electromagnetic switching valve 68, and a compressed air supply source for retracting the probe is connected to the port a via a circuit 72.
73, and a compressed air supply source 75 for inspection is connected to the port c via a circuit 74. The compressed air supply source 73 for retreating the probe in this case is opposed to the pressing force of the spring 60 to prevent the piston 56 from moving. As a result, compressed air having an air pressure capable of retracting the probe 52 is supplied, and the compressed air supply source 75 for inspection here is the compressed air supply source 72 for retracting the probe.
The compressed air is supplied at a pressure sufficiently lower than the compressed air supplied by.

By the way, when compressed air is supplied from the compressed air supply source 75 for inspection to the air outlet 54 of the tip portion 52a of the probe 52, as shown in FIG.
Is tightly fitted in the groove of the female screw 6, the air outlet
Since 54 is almost closed by the screw thread, almost no compressed air is blown out from it, and thus the air pressure (back pressure) in the circuit 74 does not decrease, but as shown in FIG. 13 (b) and FIG. 13 (c). If the thread groove is shallow or the position of the thread groove and the tip portion 52a is deviated, the tip portion 52a of the probe 52 and the thread groove of the female screw 6 are fitted between the air outlet 54 and the thread. A gap that changes depending on the state is generated, and compressed air blows out from there as indicated by the arrows in FIGS. 13 (b) and 13 (c). Therefore, the air pressure in the circuit 74 is also the tip portion 52a of the probe 52 and the screw of the female screw 6. It will decrease depending on the fitting state with the groove.

In consideration of the above facts, the apparatus of this embodiment has
Circuit that connects the port c and the inspection compressed air supply source 75
The 74 is provided with a normal pressure sensor 76 as a probe contact state detecting means for detecting the air pressure (back pressure) in the circuit 74, and the output signal of the pressure sensor 76 is as a female screw shape output means. , Is input to an arithmetic processing unit 77 including a normal microcomputer. The arithmetic processing unit 77 also receives a signal output from the control device of the machining center 63 and indicating the spindle end position and thus the position of the probe holder 51, and the arithmetic processing unit 77 cooperates with the control device of the machining center 63. The operation of the electromagnetic solenoid of the electromagnetic switching valve 68 is controlled, arithmetic processing is performed based on each of the input signals, and the result is output to a normal display device (not shown) and displayed on the screen.

Here, in the control device of the machining center 63, the screw hole 5 to be measured of the work 15 on the work table is provided.
When the data of the height, depth and horizontal position of the upper end of the machine are given, a control program is given so that the machining center 63 moves the work table and performs a predetermined measurement operation described later based on the data. Further, in the arithmetic processing unit 77, when the machining center 63 performs its measuring operation, the electromagnetic solenoid of the electromagnetic switching valve 68 is de-excited during the operation of inserting the probe holder 51 into the screw hole 5. As shown in FIG. 12, the probe retracting compressed air supply source 73 to the circuit 72, the electromagnetic switching valve 68, the circuit 70
Further, compressed air is supplied into the air chamber 66 through the air passage 65 to retract the probe 52 into the probe holder 51 and the circuit 74 is closed, and thereafter, the electromagnetic switching valve 68 of the electromagnetic switching valve 68 is set at a predetermined timing described later. Energize the electromagnetic solenoid,
Thereby, as shown in FIG. 14, the air pressure in the air chamber 66 is discharged from the exhaust silencer 71 through the air passage 65, the circuit 70 and the electromagnetic switching valve 68, and the probe 52 is moved from the probe holder 51 by the urging force of the spring 60. In addition to projecting, the low pressure compressed air as described above is supplied from the inspection compressed air supply source 75 into the air chamber 59 through the circuit 74, the electromagnetic switching valve 68, the circuit 69 and the air passage 64, and the compressed air is supplied to the air. A control program is provided to perform a control operation of supplying the air to the air outlet 54 through the passage 58.

Further, in the arithmetic processing unit 77, the depth of the screw groove is measured with high accuracy by, for example, enlarging the section of the screw hole with a magnifying projector or the like after the measurement by the device for several kinds of screw holes, The female screw 6 obtained by obtaining the correlation between the detected value of the air pressure in the circuit 76 by the pressure sensor 76 and its highly accurate measured value.
The data of the upper limit value and the lower limit value corresponding to the upper limit dimension and the lower limit dimension of the depth dimensional tolerance of the screw groove are given in advance.

In such a screw hole measuring device, the internal thread 6 in the screw hole 5 is measured in the following manner according to the control program. That is, here, in the state where the arithmetic processing unit 77 de-energizes the electromagnetic solenoid of the electromagnetic switching valve 68 and retracts the probe 52 into the probe holder 51, first, the machining center 63 moves the probe holder 51 to the position shown in FIG. After concentrically arranging above the screw hole 5, the work table is raised and the probe holder 51 is
As shown in FIG. 15, the probe 52 is inserted into the screw hole 5 from the end surface of the work 15 until the reference female screw depth L is inserted, and then the arithmetic processing unit 77 is operated by the electromagnetic switching valve 68 while the probe holder 51 is inserted. Exciting the electromagnetic solenoid,
As shown in 16, the probe 52 is projected from the probe holder 51, and compressed air is supplied to the air outlet 54 of the tip portion 52a thereof.

After the protrusion of the probe 52, the circuit 76
When the detected value of the air pressure inside is lower than the above lower limit value, as shown in FIG. 16, the tip portion 52a of the probe 52 is not tightly fitted in the thread groove of the female screw 6, and the air blown. Since it is considered that the compressed air is blowing out from the outlet 54, the machining center 63 rotates the probe holder 51 around its axis at an extremely low speed as indicated by the arrow in FIG. Continuing to check the detected value of the air pressure in the circuit 76 by the sensor 76, at the circumferential position where the detected value becomes the maximum value, as shown in FIG. 17, the tip portion 52a of the probe 52 comes into close contact with the thread groove of the female screw 6. It is determined that the probe holder 51 has been fitted to the machining center 63, the rotation of the probe holder 51 is stopped, and the maximum detected value is compared with the upper and lower limit values. If it is in the normal area between If it is determined that the tap depth and the thread groove depth at the maximum depth are normal, and if the detected value is within the abnormal region where it exceeds the upper limit, the compressed air supply source for inspection 75 and the pressure sensor 76 If the detected value is below the lower limit, it means that the tap depth is insufficient, or the thread groove is too shallow due to internal threading with a tap that exceeds the wear limit. It is determined that the tip of the tip portion 52a of the probe 52 is in contact with the inner wall of the pilot hole because it is an unmachined hole that has not been internally threaded due to breakage of the tap or the like.

Thereafter, the machining center 63 rotates the probe holder 51 around its axis at a low speed in such a direction as to loosen the screw so that the tip 52a of the probe 52 traces the thread groove of the female screw 6 and traces the valley bottom. When the probe holder 51 is pulled out slowly from the inside of the screw hole 5, the arithmetic processing unit 77 causes the circuit by the pressure sensor 76 to move.
Continuing the comparison between the detected air pressure in 76 and the upper and lower limits corresponding to the upper and lower limits of the dimensional tolerance of the female screw 6, see FIG.
As shown in the relationship diagram in (a), the detected value P is between the upper limit value A and the lower limit value B within the measurement stroke range that ignores the part where the data is inaccurate, such as the point of missing or the chamfered part of the mouth. If it is maintained within the normal range between, it is determined that the thread groove of the female screw 6 has a regular size and shape, and the detection value P starts below the lower limit value B and enters the normal range where If it is maintained, it is judged that the tap processed by the internal thread is normal but the tap depth is insufficient and the test is unacceptable. If the detection value P is maintained below the lower limit value B, the wear limit is exceeded. The threaded groove is too shallow because it has been internally threaded with a tap, or it is unapproved because it is an unmachined hole that was not threaded because of tap breakage, etc., and the detected value falls from within the normal range. If the lower limit value B is exceeded, tap center and screw hole Variations in the depth of the screw groove for eccentricity between the center was excessive determines that the failure has become excessive. Then, the arithmetic processing unit 77 outputs the determination result to the display device and displays it on the screen.

Therefore, according to the female screw measuring device of this embodiment, the goodness and the badness of the female screw 6 are measured based on the electrical detection result without depending on the sense of the measurer. The measurement result does not vary according to the above, and the measurement accuracy can be improved. Also, the tip of the probe 52
Since the shape of the female screw 6 is measured using the pressure sensor 76 that detects the contact state between the 52a and the inner wall of the screw hole 5, the tap depth of the female screw 6 and the depth of the screw groove can be quantified by one measurement operation. Can be measured accurately and accurately.

Further, according to the apparatus of this embodiment, if a plurality of types of probe holders 51 having probes 52 corresponding to screw holes 5 of different types are stored in the tool magazine of the machining center 63, unmanned operation is possible. You can inspect other types of female threads.

The tip portion 52a of the probe 52 and the screw hole 5
The contact state with the inner wall of the
Instead of installing a flow meter, insert a flow meter and
This may be done by detecting the air flow rate Q in 74. In this case, as shown in FIG.
If the air flow rate Q is maintained within the acceptable range between the upper limit value a and the lower limit value b determined in the same manner as the above example during extraction of 51, the tap depth of the internal thread 6 and the depth of the thread groove Can be determined to be within a predetermined tolerance.

[0052]

As described above, according to the first to third aspects of the invention, the shape of the female screw is obtained based on the electrical detection result without depending on the sense of the measurer. Therefore, the skill and situation of the measurer The measurement result does not vary according to the above, and the measurement accuracy can be improved. Further, since the shape of the female screw is obtained using a non-contact type distance sensor or a contact probe, various dimensions of the female screw can be quantitatively and highly accurately measured.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a female screw measuring device according to a first invention of this application.

FIG. 2 is a perspective view showing an NC machine tool in the apparatus of the above embodiment.

3 (a) to 3 (c) are explanatory views showing a method for measuring an internal thread by the apparatus of the above-mentioned embodiment.

FIG. 4 is a characteristic diagram showing a measurement result of an internal thread by the device of the above embodiment.

FIG. 5 is a configuration diagram showing an embodiment of a female screw measuring device according to the second invention of the present application.

FIG. 6 is a perspective view showing the external appearance of a probe holder advancing / retreating mechanism in the apparatus of the above-described embodiment.

FIG. 7 is a diagram showing an M of FIG.
It is sectional drawing which follows the -M line.

8A and 8B are explanatory views showing an operating state of the probe holder advancing / retreating mechanism.

9 (a) and 9 (b) are cross-sectional views showing different examples of the method of detecting the swing of the probe in the apparatus of the above-mentioned embodiment.

10A to 10D are explanatory views showing a method for measuring an internal thread by the device of the above-mentioned embodiment.

FIG. 11 is a configuration diagram showing an embodiment of a female screw measuring device of a third invention of this application.

FIG. 12 (a) is an enlarged vertical cross-sectional view showing the distal end portion of the probe holder in the apparatus of the above-mentioned embodiment, and FIG.
FIG. 4A is a cross-sectional view taken along line NN in (a).

13 (a) to 13 (c) are explanatory views showing changes in the air blowing state from the air outlet of the probe tip portion with respect to changes in the depth of the thread groove in the device of the above-mentioned embodiment.

FIG. 14 is a cross-sectional view showing the probe holder in the device of the above-described embodiment in a state where the probe is projected.

FIG. 15A is a cross-sectional view showing a state of the probe holder at the time of measuring a female screw by the device of the above-mentioned embodiment,
(B) is an arrow view seen from the arrow R direction of (a).

16 (a) is a cross-sectional view showing a state of a probe holder at the time of measuring a female screw by the device of the above embodiment, FIG.
(B) is an arrow view seen from the arrow S direction of (a).

FIG. 17 (a) is a cross-sectional view showing a state of the probe holder at the time of measuring a female screw by the device of the above-mentioned embodiment,
(B) is an arrow view seen from the arrow T direction of (a).

FIG. 18 (a) is an explanatory view showing a state of the probe and a change state of the detected value of the pressure sensor at the time of measuring the internal thread by the device of the above embodiment, and FIG. 18 (b) shows a flow meter in place of the pressure sensor. It is a relationship diagram which shows the change state of the flow volume when used.

FIG. 19 is an explanatory diagram showing a female screw measuring method using a conventional inspection tool.

FIG. 20 (a) is a front view showing another conventional inspection tool, and FIG. 20 (b) is an explanatory view showing a female screw measuring method using the inspection tool.

[Explanation of symbols] 5 Screw hole 6 Female screw 11 Sensor holder 12 Distance sensor 13 NC machine tool 15 Work piece 17,47,77 Arithmetic processing unit 21,52 Probe 21a Contact part 22,51 Probe holder 24 Probe holder forward / backward moving mechanism 52a Tip Part 55 Air cylinder 63 Machining center 76 Pressure sensor

Claims (3)

[Claims] 1. A distance sensor (12) provided in a sensor holder (11) for measuring a distance between a predetermined portion of the sensor holder inserted into a screw hole (5) and an inner wall of the screw hole in a non-contact manner. And inserting the sensor holder into the screw hole,
A sensor holder inserting means (13) for outputting the insertion depth of the sensor holder into the screw hole, and an output of the distance sensor with the sensor holder inserted into the screw hole, relative to the inner wall of the screw hole. Female screw shape output means (17) for outputting the shape of the female screw (6) in the screw hole based on the output signal indicating the distance and the output signal indicating the insertion depth of the sensor holder output by the sensor holder inserting means. ), And a female screw measuring device comprising. 2. A probe (21) having a base pivotally supported by a probe holder (22) inserted into a screw hole (5) and protruding laterally from the probe holder (21), and the probe holder protruding direction of the probe (21). Probe holder advance / retreat moving means (24) for advancing / retreating to an arbitrary position and outputting the advance / retreat movement direction position of the tip of the probe, and a probe for detecting contact between the inner wall of the screw hole and the tip of the probe. Contact detection means (21a), probe holder insertion means for inserting the probe holder into the screw hole and outputting the insertion depth of the probe holder into the screw hole, and the probe contact detection means for outputting , An output signal notifying the contact between the inner wall of the screw hole and the tip of the probe, and the advance of the tip of the probe output by the probe holder advancing / retreating means. An output signal indicating the direction of movement position, and outputs said probe holder insertion means, based on a signal indicating the insertion depth of the probe holder, the internal thread of the threaded bore (6)
A female screw measuring device comprising: a female screw shape output means (47) for outputting the shape of. 3. A female screw (6) in the screw hole, which is supported by a probe holder (51) inserted in the screw hole (5) so as to project laterally from the probe holder.
Probe (5 with a tip that can be closely fitted to the thread groove of
2), a probe advancing / retracting moving means (55) for projecting and retracting the probe with respect to the probe holder, and a probe contact state detecting means (detecting a contact state between an inner wall of the screw hole and a tip portion of the probe ( 76), probe holder inserting means (63) for inserting the probe holder into the screw hole and outputting the insertion depth of the holder into the screw hole, and outputting by the probe contact state detecting means, Based on an output signal indicating the contact state between the inner wall of the screw hole and the tip of the probe and a signal indicating the insertion depth of the probe holder output by the probe holder inserting means, the shape of the female screw in the screw hole is determined. Female thread shape output means for output (77)
And a female screw measuring device.