JPH06323835A - Screw hole measuring apparatus - Google Patents

Abstract

PURPOSE:To allow quantitative measurement of the radial dimension of screw hole, the effective depth of screw, and the hole position by turning the air blow-out port of a screw measuring rod one revolution while advancing/ retracting the measuring rod along the spiral screw thread and determining the variation in the distance between the air blow-out port and the screw thread. CONSTITUTION:A controller 11 receives a signal from a personal computor 10 to actuate a three-dimensional shifting mechanism 6 which inserts a screw measuring rod 5 into a screw hole 4 with no interference of a screw thread 4a. An air blow-out port 5a is then turned one revolution while advancing or retracting along the spiral screw thread 4a and the distance between the blow- out port 5a and the screw thread 4a is determined based on the output from a pressure/voltage converter 9. The direction of shortest or longest distance is then determined and the central position of the screw hole 4 is measured 10 followed by the measurement of the inner diameter (d) of the screw 4, the diameter D at the root of thread, and the effective screw depth L based on the variation in the distance between the blow-out port 5a and the screw thread 4a detected by the measuring rod 5 during movement thereof. This constitution allows quantitative measurement while reducing the manpower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw hole of a work,
The present invention relates to a device for automatically measuring a radial dimension, an effective screw depth and a hole position.

[0002]

2. Description of the Related Art Conventionally, in the case of performing the above-mentioned measurement, the thread diameter and the effective thread depth of a screw hole are the same as those of a normal inspection limit thread gauge 1 as shown in FIG. By alternately screwing and into the screw holes by hand, if the passing gauge can be screwed up to the specified effective thread depth while the stop gauge is not screwing in, it is measured that it is within the tolerance range. As shown in FIG. 11 (b), it is said that the shaft portion of the screw gauge 2 manually screwed into the screw hole is touched by the probe 3 of the general-purpose coordinate measuring machine to obtain the position of the shaft portion. Was going by the way.

[0003]

However, in such a conventional method for measuring a screw hole, since the limit screw gauge 1 is used to measure the screw diameter and the effective screw depth, it depends on the human sense. There is a problem that quantitative measurement is not possible and the number of man-hours for measuring increases, and it is not possible to measure the hole position without setting the work on the coordinate measuring machine, so it is essential to measure on the line. However, there is a problem that the number of man-hours for measuring is also increased.

By the way, in recent years, pressurized air is blown from an air outlet toward an object to be measured, and a change state of the back pressure of the pressurized air is measured to measure the difference between the object and the air outlet. An air micrometer that measures a distance is known, and if this is used, the distance to an object can be quantitatively measured without contact.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus which advantageously solves the problems of the conventional measuring method by utilizing the principle of the air micrometer described above. The first screw hole measuring device of No. 1 is a screw measuring element which is inserted into a measured screw hole and blows pressurized air from an air outlet toward a screw thread in the screw hole, and the screw measuring element. A screw gauge moving means that is inserted into a screw hole to rotate and move back and forth within the screw hole, and the air outlet and the screw based on a change in back pressure of pressurized air supplied to the air outlet. Distance measuring means for outputting a signal corresponding to the distance to the crest, and the screw measuring element moves in the advancing / retracting direction so as to move the air outlet along the spiral of the screw thread in the screw hole. Change of the distance obtained during one rotation while Based on the above, the direction in which the distance is the shortest or the longest is examined, and the center position measuring means for measuring the center position of the screw hole from the distance and the direction in the opposite direction, and the screw measuring element is the screw hole. And a screw dimension measuring means for measuring an inner diameter, a root diameter, and an effective screw depth of the screw hole based on a change in the distance obtained while moving in the forward and backward directions.

The second screw hole measuring device of the present invention is
A screw gauge that is inserted into the measured screw hole and blows pressurized air from the air outlet toward the screw thread in the screw hole, and the screw gauge is inserted into the screw hole and the screw hole A screw gauge moving means for rotating and advancing and retracting inside, a contact detecting means for detecting contact between the screw gauge and a screw thread in the screw hole, and pressurized air supplied to the air outlet. Based on the change in the back pressure of the, when the distance measuring means for outputting a signal corresponding to the distance between the air outlet and the screw thread, and when contacting the screw thread at a plurality of positions in the circumferential direction of the screw hole. Based on the position of the screw measuring element, based on the change of the distance obtained while moving the center position measuring means for measuring the central position of the screw hole and the screw measuring element in the screw hole in the advancing and retracting direction. , The radial dimension of the screw hole and the effective thread depth A screw size measurement means for measuring is made comprises a.

[0007]

In the first device, the screw gauge moving means first moves the screw gauge to a position substantially aligned with the screw hole to be measured, and then inserts the screw gauge into the screw hole. Rotating and advancing / retreating in the screw hole, and during the rotation and advancing / retreating movement in the screw hole, the screw gauge blows pressurized air from the air outlet toward the screw thread in the screw hole,
As a result, the distance measuring means outputs a signal corresponding to the distance between the air outlet and the screw thread based on the change in the back pressure of the pressurized air supplied to the air outlet, and measures the center position. Means, based on the change in the distance obtained during one rotation while the screw probe moves in the advancing and retracting direction so as to move the air outlet along the spiral of the screw thread in the screw hole, The direction in which the distance is the shortest or the longest is examined, and the center position of the screw hole is measured from the distance in that direction and the direction opposite thereto, and the screw dimension measuring means causes the screw gauge to measure the inside of the screw hole. The inner diameter, the root diameter, and the effective screw depth of the screw hole are measured based on the change in the distance obtained while moving in the advancing / retreating direction.

Therefore, according to this first device, the radial dimension, effective screw depth and hole position of the screw hole of the workpiece are automatically determined based on the change in the distance between the air outlet and the screw thread. Since the measurement can be performed, all the measurement can be quantitatively performed, and the man-hour required for the measurement can be reduced. According to this device,
Since the measurement can be performed without using a three-dimensional measuring machine, it is possible to perform the measurement on the line and reduce the man-hour required for setting the work at the time of measurement.

In the second device, the screw gauge moving means first moves the screw gauge to a position approximately aligned with the screw hole to be measured, and then inserts the screw gauge into the screw hole. , In the screw hole in the direction perpendicular to the axis of the screw hole,
Move until the contact detection means detects contact between the thread measuring element and the screw thread in the screw hole, and bring the thread measuring element into contact with the screw thread at a plurality of positions in the circumferential direction of the screw hole. Based on the position of the screw probe, the center position measuring means measures the center position of the screw hole, and then the screw probe moving means rotates and moves the screw probe in the screw hole to move the screw. During rotation and reciprocation in the hole,
The screw gauge blows pressurized air from the air outlet toward the threads in the screw hole, whereby the distance measuring means changes the back pressure of the pressurized air supplied to the air outlet. A signal corresponding to the distance between the air outlet and the screw thread, and the screw dimension measuring means obtains the distance while the screw probe moves in the screw hole in the advancing / retreating direction. The radial dimension of the screw hole and the effective screw depth are measured based on the change of

Therefore, also with this second device, the radial dimension of the screw hole of the workpiece, the effective screw depth, and the hole position are determined by the position of the thread contact point in contact with the screw thread, the air outlet, and the screw thread. Since automatic measurement can be performed based on the change in the distance between and, all of these measurements can be performed quantitatively, and the man-hours required for the measurement can be reduced. Since the measurement can be performed without using it, it is possible to perform the measurement on the line and reduce the man-hour required for setting the work at the time of measurement.

[0011]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of a first screw hole measuring device of the present invention. The device of this embodiment is for measuring various sizes and hole positions of a screw hole 4 of a work. In addition, it is possible to move the screw measuring element 5 having the air outlet 5a on the side surface, and to move the screw measuring element 5 to an arbitrary position in the three-dimensional direction, and to rotate the screw measuring element 5 at an arbitrary angle around the center line C _d. , A three-dimensional moving mechanism 6 which is, for example, a tool moving mechanism of a normal NC machine tool, and a pressurized air supplied from a pressurized air supply source 7 such as an air line of a factory The pressurized air adjusting circuit 8 which is adjusted and supplied to the air outlet 5a of the screw gauge 5, is inserted between the pressurized air adjusting circuit 8 and the air outlet 5a, and is supplied to the air outlet 5a. Distance measuring means that converts the change in back pressure of pressurized air into a change in voltage and outputs the voltage. Pressure as
A voltage converter 9 and an ordinary personal computer as a center position measuring means and a screw dimension measuring means for converting the output voltage of the pressure-voltage converter 9 into a digital value and measuring various dimensions of the screw hole based on the value. It comprises a (so-called personal computer) 10 and a controller 11 for numerically controlling the operation of the three-dimensional moving mechanism 6 based on a signal from the personal computer 10, for example, a controller 11 of the NC machine tool having a normal microcomputer. .

Here, the pressurized air adjusting circuit 8 includes, for example, an opening / closing valve 8a, a submicron air filter 8b, an oil mist separator 8c, a regulator 8d, and a pressure reducing valve 8e as shown in FIG. The pressure-voltage converter 9 can be configured by connecting in series, and for example, as shown in FIG. 2 as well, the pressure-voltage converter 9 has two circuits 9a and 9b for branching the supplied pressurized air, which are generally used. Both sides of the pressure-sensitive diaphragm of the differential pressure detector 9c are respectively connected via a throttle valve 9d, and one of these circuits 9a is opened to the atmosphere via the throttle valve 9e, while the other circuit 9b is opened. Is a pressurized air supply path connected to the air outlet 5a of the screw probe 5, and further amplifies the change in capacitance due to the displacement of the pressure-sensitive diaphragm and the change in resistance value of the resistance constituting the bridge. Amplification (not shown) It can be configured by providing a container. Since the screw gauge 5 rotates, an air circuit is connected between the air outlet 5a of the screw gauge 5 and the circuit 9b while permitting rotation of the screw gauge 5, and a normal rotary not shown. Connected by a formula coupler.

When measuring one or a plurality of screw holes 4 of a work by using such an apparatus, the procedure shown in FIG. That is, here, after the work is positioned at the predetermined position, first, in step 21, the controller 11 operates the three-dimensional movement mechanism 6 in response to a signal from the personal computer 10 to move the screw contact point 5 into the screw hole 4. The screw measuring element 5 is moved to a position where the center line C _h of the screw hole 4 and the center line C _d of the screw measuring element 5 face each other and substantially coincide with each other.
Can be inserted into the screw hole 4 without interfering with the thread 4a of the screw hole 4.

Here, when the workpiece positioning accuracy is sufficiently high, the movement to the position facing the screw hole 4 is based on the data given in advance, and based on the workpiece positioning position, the screw hole in the design is set. Screw probe 5 at position 4
Can be automatically moved. However, when the positioning accuracy of the work is not so high, for example, the three-dimensional moving mechanism 6 is manually operated to operate the screw measuring element of the work shown in FIG. After fitting the screw measuring element 5 in the reference hole 12 having a diameter slightly larger than 5, the screw measuring element 5 is placed at the designed position of the screw hole 4 with the position of the reference hole 12 as a reference.
By automatically moving.

When the positioning accuracy of the work is not so high, the screw measuring element 5 is located at a position facing the screw hole 4.
May also be carried out by the method shown in FIGS. 4 and 5,
According to the method shown in FIG. 4, air outlets 5b are provided at the lower end of the thread measuring element 5 in a diagonally downward direction toward all directions, and the thread measuring element is located at the position of the screw hole 4 on the basis of the positioning position of the workpiece. After automatically moving 5, the voltage change based on the change in the back pressure of the pressurized air supplied to the four air outlets 5b is independently measured by switching the air circuit, etc. Position the four air outlets 5b
Are corrected so that the four voltage values respectively corresponding to are equal to each other. According to this method, since the distance between each of the four air outlets 5b and the chamfered portion 4b at the inlet of the screw hole 4 becomes equal after the position correction, the center line C _d of the screw contact point 5 becomes It coincides with the center line C _h of the hole 4 with a relatively high degree of accuracy, and therefore, when the screw 4 is inserted into the screw hole 4,
Interference with 4a can be reliably prevented.

Then, in the method shown in FIG.
An air outlet 5c is provided downward at the lower end of the, and the screw probe 5 is automatically moved to the position of the screw hole 4 in the design based on the positioning position of the work, and then supplied to the air outlet 5c. While measuring the voltage change based on the change in the back pressure of the pressurized air, the screw probe 5 is moved in two directions perpendicular to the center line C _d thereof so as to cross the screw hole 4 as indicated by the arrow in the figure. Then, find the position where the voltage becomes the minimum in each of those two directions, that is, the position where the back pressure of the pressurized air becomes the minimum because the distance between the air outlet 5c and the workpiece becomes the maximum, and based on those positions. the corrected position offset amount of the air outlet 5c of the center line C _d, wherein the position of the center line C _h of the screw hole 4 for each direction, the center line C _d is the center line C of the screw measuring element 5 Correct the position of the screw stylus 5 so as to match _h . According to this method, the position of the screw gauge 5 is corrected by using the position of the center line C _h of the screw hole 4 that is actually obtained, so that the center line C _d of the screw gauge 5 is the center line of the screw hole 4. It matches C _h with a relatively high degree of accuracy, and therefore even in this method, when the screw is inserted into the screw hole 4, the screw probe 5 and the screw thread 4a
Interference with can be reliably prevented.

After moving the screw head 5 to the position facing the screw hole 4 as described above, here, in step 22,
The controller 11 operates the three-dimensional movement mechanism 6 in response to a signal from the personal computer 10 to move the screw contact 5
As shown in FIG. 1, is inserted into the screw hole 4 to an intermediate depth close to the inlet of the hole, but to the extent that pressurized air from the air outlet 5c does not leak out of the hole. In addition, when the thread hole 4 is clogged with foreign matter, the above-mentioned insertion causes the screw probe 5 to move.
In order to prevent the damage of the screw, in the actual device, as shown in FIG. 6, the screw probe 5 is usually supported by the holder 6a of the three-dimensional moving mechanism 6 so as to be retractable therein, and is screwed by the spring. A structure is adopted in which the tracing stylus 5 is constantly urged to advance. In that case, when the screw tracing stylus 5 is retracted, preferably, as shown in the drawing, the compressed air supply port 6b to the air outlet 5a is retracted. Provide in a closed position. With this arrangement, when the screw probe 5 is retracted by coming into contact with the foreign matter 13 in the screw hole 4 by the above insertion, the back pressure of the pressurized air for screw hole measurement rises abnormally due to the closing of the supply port 6b. Since the voltage change also shows an abnormal rise, the contact of the screw measuring element 5 with the foreign matter 13 can be easily known without detecting with a separate sensor or switch, and therefore the rotating screw measuring element It is possible to avoid complication of electric wiring due to the additional provision of a sensor and a switch to 5.

When the screw gauge 5 is inserted into the screw hole 4 up to an intermediate depth close to the inlet, here, in step 23,
Then, the controller 11 operates the three-dimensional movement mechanism 6 in response to a signal from the personal computer 10, and, for example, NC
By a program similar to the rigid tap function of the machine tool, as shown in FIG. 7 (a), the thread measuring element 5 has one pitch of the screw thread 4a from the insertion position shown by the solid line in the figure to the position shown by the imaginary line in the figure. (P) While moving in the approach direction and rotating once in synchronism with the movement, the air outlet 5a is moved by one pitch along the spiral of the screw thread 4a, and pressure-voltage is applied during the movement. The air outlet 5a and the screw thread 4a along the spiral of the screw thread 4a for one pitch, which is continuously output by the converter 9.
The change of the voltage corresponding to the change of the distance between and is examined by the personal computer 10 to find the direction of the screw probe 5 where the voltage becomes maximum.

Here, the back pressure of the pressurized air increases as the distance between the air outlet 5a and the screw thread 4a becomes shorter, because the resistance of the pressurized air from the air outlet 5a increases. However, it is known that the increase in the back pressure increases the output voltage of the pressure-voltage converter 9, and the change in the distance and the change in the output voltage have a substantially linear relationship. Therefore, as shown in FIG. 7B, the direction of the threaded probe 5 where the above voltage is maximized is the direction in which the distance between the air outlet 5a and the screw thread 4a is the shortest. If the value of the output voltage is converted into a distance by the personal computer 10 using a conversion table, a conversion formula, or the like obtained in advance by a test, the air outlet can be obtained.
The distance between the thread 5a and the thread 4a, and thus the position of the thread 4a where the air outlet 5a faces can be determined.

In the next step 24, the controller 11 operates the three-dimensional moving mechanism 6 in response to a signal from the personal computer 10 to direct the screw probe 5 toward the direction of the shortest distance, and then, in that direction, As shown in FIG.
Move the thread 4a in the approach direction by 2 to 3 pitches (P),
The personal computer 10 changes the voltage corresponding to the change in the distance between the air outlet 5a and the screw thread 4a, which is continuously output by the pressure-voltage converter 9 during the movement, as shown in FIG. Finding the peak position of the screw thread 4a by converting the average value of the maximum values M during the voltage change into a distance, and converting the average value of the minimum values m during the voltage change into a distance. The bottom position of the thread 4a is obtained by the above, and the apex position and the bottom position of the thread 4a at the point A in the circumferential direction of the thread 4a shown in FIG.

In the next step 25, the controller 11 operates the three-dimensional moving mechanism 6 in response to a signal from the personal computer 10 to rotate the screw measuring element 5 by 180 °, thereby causing the air outlet 5a to move in the opposite direction. Direction, that is, in the direction in which the distance between the air outlet 5a and the screw thread 4a is the longest, in the following step 26, the top position of the screw thread 4a is determined and the root of the screw thread 4a is obtained in the same manner as in step 24. The position is calculated, and the screw thread shown in FIG.
Thread 4a at point B, which is 180 ° rotated from point A, in the circumferential direction of 4a
Find the vertex position and the valley bottom position of. Here, the points A and B face each other in the diameter direction of the screw hole 4. Therefore, in the following step 27, the personal computer 10 calculates and calculates the inner diameter d of the screw hole 4 shown in FIG. 1 which is the distance between the apex positions of the screw threads 4a at the points A and B. The root diameter D of the screw hole 4 shown in FIG. 1, which is the distance between the root positions of the thread 4a at the points A and B, is obtained.

In the next step 28, the controller 11 operates the three-dimensional moving mechanism 6 in response to a signal from the personal computer 10 so that the screw gauge 5 is designed, for example, as shown in FIG. After advancing to a position deeper than the value L _d by 2 pitches, it is moved backward from that position to, for example, a position shallower than the design value L _d by 1 pitch, and the pressure-voltage converter is moved during the movement. 9 continuously output, as shown in FIG. 9, the personal computer 10 examines the change in voltage corresponding to the change in the distance between the air outlet 5a and the screw thread 4a. The distance between the root of 4a and the bottom of the root falls within a predetermined range based on the dimensional tolerance with respect to the distance used as the basis for obtaining the root diameter D first, that is, the height of the screw thread 4a maintains the predetermined height. Find the maximum approach depth of exit 5a The depth and effective thread depth L.

In the final step 29, the midpoint between the apex positions or the valley bottom positions of the thread 4a at the points A and B is obtained. The midpoint is the center line C _{h of the} screw hole 4.
Position, that is, the hole position of the screw hole 4.

Therefore, according to the apparatus of this embodiment, the inner diameter d, the root diameter D, the effective thread depth L and the hole position of the screw hole 4 of the work are set between the air outlet 5a and the screw thread 4a. Since automatic measurement can be performed based on a change in distance, it is possible to perform all of these measurements quantitatively and reduce the number of man-hours required for the measurement. Further, according to this apparatus, since it is possible to perform measurement using a normal NC machine tool without using a three-dimensional measuring machine, it is possible to perform measurement on a work processing line and to set a work at the time of measurement. The man-hour can be reduced.

FIG. 11 is a block diagram showing an embodiment of the second screw hole measuring device of the present invention. In the figure, the same parts as those shown in FIG. 1 are designated by the same reference numerals. That is, the apparatus of this embodiment is also for measuring various dimensions and hole positions of the screw hole 4 of the work, and includes the screw probe 5 having the air outlet 5a on the side surface and the screw probe 5. Three-dimensional movement, which is, for example, a tool moving mechanism of a normal NC machine tool, as a screw gauge moving means that can be moved to any position in the three-dimensional direction and can be rotated about the center line C _d thereof at any angle. Pressurized air adjusting circuit 8 for appropriately adjusting the pressurized air supplied from the mechanism 6 and the pressurized air supply source 7 such as the factory air line and supplying the air to the air outlet 5a of the screw probe 5.
The distance between the compressed air adjusting circuit 8 and the air outlet 5a, which converts the change in back pressure of the compressed air supplied to the air outlet 5a into a change in voltage and outputs it. A pressure-voltage converter 9 as a measuring means, and a center position measuring means and a screw dimension measuring means for converting the output voltage of the pressure-voltage converter 9 into a digital value and measuring various dimensions of the screw hole based on the value. An ordinary personal computer (personal computer) 10, and a controller 11 for numerically controlling the operation of the three-dimensional moving mechanism 6 based on a signal from the personal computer 10, for example, a controller 11 of the NC machine tool having an ordinary microcomputer. And a probe device as contact detecting means for detecting that the screw probe 5 is in contact with the screw thread 4a between the screw probe 5 and the three-dimensional moving mechanism 6. Become comprises a 14.

Here, the probe device 14 is mounted on the three-dimensional moving mechanism 6 and allows the thread measuring element 5 to come into contact with the screw thread 4a and move in parallel or tilt relative to the device 14. At the same time, the screw measuring element 5 is elastically supported by a known supporting mechanism so as to return the screw measuring element 5 to a predetermined original position with respect to the device 14 when the contact is eliminated, and the screw measuring element 5 The contact with the screw thread 4a is detected by a piezoelectric element or the like that detects the operation of the support mechanism, or is detected from the electrical connection between the screw measuring element 5 and the screw thread 4a, and the personal computer 10 is notified accordingly. The signal of is output. Further, although the screw gauge 5 rotates, its rotation angle is 360 degrees at the maximum. Therefore, the screw gauge 5 rotates 360 degrees between the air outlet 5a of the screw gauge 5 and the circuit 9b. Is connected by an air hose (not shown) having an appropriate length for connecting the air circuit.

When measuring one or a plurality of screw holes 4 of a work using such an apparatus, the procedure shown in FIG. That is, here, after the work is positioned at a predetermined position, first, in step 31, for example, a signal from the personal computer 10 based on previously given data is used to operate the three-dimensional moving mechanism 6 by the controller 11 to measure the screw. The child 5 is moved to a position facing the screw hole 4 and the center line C _h of the screw hole 4 and the center line C _d of the screw measuring element 5 are substantially aligned, and from that position, as shown in FIG. As shown, the screw probe 5 is moved forward and inserted into the screw hole 4 without interfering with the screw thread 4a in the screw hole 4 to a position slightly inserted from the inlet.

Then, in step 32, the controller 11 operates the three-dimensional moving mechanism 6 in response to a signal from the personal computer 10 to move the screw head 5 to the position shown in FIG.
As shown in (b), the screw hole 4 is moved in a plurality of directions in which the center position of the screw hole can be specified, that is, in the four directions perpendicular to the axis of the screw hole and at right angles to each other. During the movement, the presence or absence of a signal from the probe device 14 is monitored by the personal computer 10, and as soon as the probe device 14 outputs a signal indicating that the screw measuring element 5 has come into contact with the screw thread 4a, the movement of the screw measuring element 5 is stopped. The position of each of the screw gauges 5 which is stopped and corrected for the movement of the response time at the time of contact with the screw thread 4a is obtained in each of the above four directions, and the outer circumference of the screw gauges 5 at those positions is determined. By calculating the center position of the circle in which the surface is inscribed, the center position of the screw hole 4 is obtained, and it is checked whether or not the center position is within a predetermined tolerance to determine whether the center position is acceptable or not.

Then, in step 33, the controller 11 operates the three-dimensional moving mechanism 6 in response to a signal from the personal computer 10 to move the screw head 5 to the position shown in FIG.
As shown in (a) and (b), after once moving to the screw hole center position, in step 34, the controller 11 operates the three-dimensional moving mechanism 6 in response to a signal from the personal computer 10 to move the screw. Fig. 15 (b)
As shown in FIG. 5, the air outlet 5a is directed in the air outlet direction corresponding to the inner diameter of the screw hole 4.
Move until 5a and the screw thread 4a come close to a predetermined distance,
During the movement, in order to prevent the screw probe 5 from running out of control, air is blown from the air outlet 5a and the personal computer 10 monitors the voltage converted from the air pressure by the pressure-voltage converter 9.

During the above movement, if the air outlet 5a of the thread measuring element 5 comes too close to the thread 4a and the air pressure exceeds the allowable value, the process proceeds from step 35 to step 36, and the thread measuring element is moved. After stopping the movement of 5 and investigating the cause of the excessive approach and removing the cause, the screw probe 5 is returned to the center position of the screw hole again and the process returns to step 34. With this, for example, when the inner diameter of the actual screw hole is smaller than the set inner diameter due to a mistake in setting the inner diameter of the screw hole to be measured, or when foreign matter is attached to the screw thread, the movement causes excessive interference. It is possible to effectively prevent the screw stylus 5 and the screw thread 4a from being broken. If only the screw hole inner diameter is checked, the screw hole inner diameter can be calculated from the position at the time of contact with the screw thread 4a of the screw measuring element 5 obtained in step 32.

On the other hand, when the air pressure does not exceed the allowable value during the above movement, the process proceeds from step 35 to step 37, and the controller 11 operates the three-dimensional movement mechanism 6 by the signal from the personal computer 10. 15A, the screw probe 5 is moved in the tap depth direction, that is, the hole bottom direction, and air is blown out from the air outlet 5a during the movement, and In the computer 10, the pressure-voltage converter 9 takes in the voltage converted from the air pressure and records the change state of the voltage. As a result, the first screw hole measurement is performed, and then, in step 38, the controller 11 operates the three-dimensional moving mechanism 6 by a signal from the personal computer 10,
The screw probe 5 is returned to the center position of the screw hole, and at that position, it is inverted 180 degrees around the center line C _d .

After that, as shown in FIG. 16 (b),
In the same manner as in steps 34 to 36 described above, the screw probe 5 is prevented from running away while the screw probe 5 is moved in the air blowing direction so that the air outlet 5a and the screw thread 4a corresponding to the inner diameter of the screw hole 4 are formed. Move until approaching a predetermined distance, then step 42
Then, in the same manner as in step 37 above, set the screw probe 5 in FIG.
(A) As shown by the middle arrow, move it toward the screw hole inlet,
Air is blown out from the air outlet 5a during the movement, and the personal computer 10 takes in the voltage converted from the air pressure by the pressure-voltage converter 9 and records the change state of the voltage. As a result, the second screw hole measurement is performed, and then, in step 43, the controller 11 operates the three-dimensional movement mechanism 6 in response to the signal from the personal computer 10 to move the screw contact 5 to the screw hole 4 While moving to the outside, the data of the change state of the voltage obtained by the above-mentioned two screw hole measurements is personal computer 10,
Based on, for example, the average value of the above-mentioned two measurement data, the actual effectiveness of the screw hole 4 is compared with a graph or a relationship table showing the relationship between the distance between the screw thread and the air outlet 5a and the voltage. The diameter and the effective screw depth are obtained, and they are compared with the set value to judge whether the dimensions of the screw hole 4 are acceptable or not.

Therefore, also by the device of this embodiment, the effective diameter, the effective screw depth and the hole position of the screw hole 4 of the workpiece are automatically determined based on the change in the distance between the air outlet 5a and the screw thread 4a. Since it is possible to measure, it is possible to perform all of these measurements quantitatively, reduce the number of man-hours required for the measurement, and use a normal NC machine tool without using a coordinate measuring machine. Since it is possible to perform measurement on the workpiece processing line, it is possible to reduce the number of man-hours required to set the workpiece at the time of measurement.

Further, FIG. 17 shows another embodiment of the first device of the present invention, which is capable of simultaneously measuring a plurality of tap holes using an NC turret machine capable of mounting a plurality of machining heads having a multi-axis cutting tool. The multi-axis tap hole measuring device is shown as an embodiment, and the same parts as those in the above-mentioned embodiment are designated by the same reference numerals.

The NC turret machine, which is the main part of this apparatus, comprises a turret head 49, a turret head indexing drive unit 50, and a feed unit 51.
Here, the turret head 49 has a head mounting surface to which a maximum of four processing heads can be mounted, and is indexed and rotated so that the machining heads are moved to predetermined indexing positions for processing on the left side in FIG. With one positioned,
A plurality of tools mounted on the machining head located at the indexing position are simultaneously driven to rotate, and the turret head indexing drive unit 50 causes the turret head 49 to index and rotate as described above, and the feed unit 51.
Moves the turret head indexing drive unit 50 together with the turret head 49 in the directions of the X, Y and Z axes which are perpendicular to each other, and positions the tool of the machining head located at the predetermined indexing position and performs cutting feed.

In this embodiment, since the NC turret machine is used to perform simultaneous processing of a plurality of tap holes, cleaning and air blowing of the holes, and inspection of the tap holes in the same step, On the head mounting surface of the turret head 49, a drill head 52 and a tap head 53
And a cleaning / air blow head 54, three types of processing heads are attached, and a measurement head 55 having a rotation transmission structure similar to those processing heads is attached.

FIG. 18 is an explanatory view showing the internal structure of the measuring head 55 and the control system of the apparatus of this embodiment. The head body of the measuring head 55 has a front cover 56,
It is composed of a center case 57 and a rear case 58, and rotatably supports a plurality of spindles 59 and a driven shaft 60. The spindles 59 are driven shafts.
60, the driving shaft 60 is drivingly coupled via a gear transmission mechanism 61, and when the measuring head 55 is located at the predetermined indexing position, the driven shaft 60 is driven by a spindle driving motor 63 in a turret head 49 via a spindle coupling 62. It is drivingly connected to a main shaft 64 which is rotationally driven. The operation of the spindle drive motor 63 is controlled by the controller 11 connected to the personal computer 10, and the controller 11 also controls the operations of the X-axis motor, the Y-axis motor and the Z-axis motor of the feed unit 51. .

A rod 65 is housed in each spindle 59 such that the rod 65 can move forward and backward and rotate integrally with the spindle 59. Each rod 65 is constantly urged by a spring 66 in the forward direction. At the same time, the cap 67 prevents the spindle 59 from slipping out, and an air passage leading to the tip is formed therein. As shown in FIG. 19, the tip end of the rod 65 is provided with a screw gauge 5 having an air outlet 5a in the lateral direction at the tip, and the rod inside the spindle 59 is attached to each screw gauge 5.
A rotary joint (rotary coupler) mechanism 68 is formed in the center case 57 of the measuring head 55 for individually supplying pressurized air for measurement via 65, and the pressurized air is adjusted to the rotary joint mechanism 68. The supply of the pressurized air from the circuit 8 can be performed via the coupling device 69.

This coupling device 69 is shown in FIG. 20 and FIG.
As shown in 21, each machining head 52-54 and measuring head
55 includes a coupling manifold 70 fixed to each side surface of the 55, and a nipple manifold 72 that is provided in the turret head indexing drive unit 50 so as to be able to move forward and backward and is driven forward and backward by a cylinder 71. The coupling manifold 70 of one of the heads 52 to 55 located at the predetermined indexing position
Where each coupling manifold 70 has a fluid required by the corresponding head, namely, the cooling fluid for the drill head 52 and the tap head 53, the cooling oil and the air curtain air, the cleaning / The air blow head 54 is provided with only ports for supplying cleaning oil and air blow air for cleaning, and the measuring head 55 is provided with a port for supplying pressurized air for measurement, while the nipple manifold 72 is provided with each of the heads 52 to 52 fitted to it. An air curtain port 72a, a cutting oil port 72b, an air blow port 72c and a measurement pressurizing air port 72d are provided to supply the respective fluids to the 55, and these ports 72a to 72d are connected via a hose 73. Is connected to the pressurized air adjusting circuit 8 and a cutting oil supply source (not shown).

According to such an apparatus, as shown in FIG. 19, a tap hole extending in the horizontal direction is obtained by the same procedure as that of the flow chart shown in FIG. 3 of the above-described embodiment of the first apparatus. The center position, the radial dimension, and the effective screw depth of 4 can be measured simultaneously for a plurality of tap holes 4, and the measurement time of these tap holes is greatly reduced compared to the case of measuring one by one. Moreover, since the tap hole processing, air cleaning and inspection can be performed in the same process, it is possible to perform quality control for each processing station,
It is possible to build a particularly effective production system on a high-volume production line with a monthly production of about 10,000 units.

The rod 65 is housed in the spindle 59 so as to be movable back and forth and is constantly urged by the spring 66 because the tap hole to be measured is clogged with a broken cutting tool or foreign matter such as cutting chips. When there is a processing defect such as a large deviation in the processing position of the tap hole, and the screw probe 5 in the feed movement comes into contact with those foreign matter and the peripheral portion of the hole, the screw probe 5 retracts. Therefore, the screw probe 5 is protected from the above-mentioned processing defects. Further, here, in order to detect these machining defects, a detection dock 74 is provided at the rear end portion of each rod 65, and the head main body of the measuring head 55 is provided with the rod 65 and thus the rod 65 due to the retreat of each screw gauge 5. Sensors 75 that detect the backward movement of the detection dock 74 are fixed, and the backward signals output by the sensors 75 are sent to the personal computer 10 via the contactless multipoint transmitter 76.
Entered in. Therefore, according to this device, it is possible to automatically detect a machining defect such as a breakage of a cutting tool, a clogging of a tap hole due to cutting chips, or a large deviation in hole position while protecting the screw probe 5 from them. You can also

FIG. 22 is applied to the inspection process of the production equipment,
1 shows an application example of the first and second devices of the present invention, in which a screw head 5 is directly connected to an NC machine 81, which can perform contouring feed described later, corresponding to the first device. Of the casting rough material shown in FIG. 23 (a) by being mounted by a sensor capable of detecting contact with the workpiece corresponding to the second device. Foreign matter, hole shapes such as splines, serrations, and snap ring grooves shown in FIG. 2 (b), missing parts of bearing rollers and balls shown in FIG. 2 (c), valve seats and bearing outer races shown in FIG. 2 (d). Seating failure, same figure (e)
It is used for inspection of burrs and the like in the cross holes shown in.

Specifically, after the workpiece 82 to be inspected is positioned and fixed at a predetermined position of the NC machine 81, the screw gauge 5 is moved as shown in phantom in FIG. 22 and as shown in FIG. It is inserted into the hole 82a of the inspection target work 82,
The screw probe 5 is contour-fed in the hole 82a. That is, the screw probe 5 rotates about its own center line C _d at the same time as shown by the solid arrow in FIG.
As indicated by arrows in broken line in FIG. 24, proceed forward while revolving the center line C _h around the hole 82a, facing the air-blowing outlet 5a though the inner wall surface of the always-hole 82a so as to traced threads While moving, it is preferably moved spirally at a pitch of about 1 to 2 mm. According to this method, the screw probe 5 has holes 82.
Since it is possible to scan the inside of a thoroughly, for example, if there are nests, cracks, foreign matter, etc., they are automatically detected as changes in the back pressure of the pressurized air for measurement as shown in Fig. 25. In addition, it is possible to detect the size of such burrows, cracks, foreign substances, etc., and also the above-mentioned hole shapes such as splines, serrations, snap ring grooves, missing parts of bearing rollers and balls, valve seats and bearing outer parts. Bad seating in races, burrs in cross holes, etc. can be automatically and easily detected.

The inner diameter of the air outlet 5a is preferably 1
~ 2 mm, and the gap between the inner wall surface of the hole 82a and the air outlet 5a
0.1 to 0.2 mm and pressurizing air pressure 0.2 to 0.5 kg / cm ²
Then, a nest, a crack, a foreign matter, or the like can be detected with high sensitivity of about 10 μ.

Although the present invention has been described above based on the illustrated example, the present invention is not limited to the above example. For example, in step 23 in FIG. The process of obtaining the hole position in step 29 may be performed by the steps up to step 26 in which the apex position or the valley bottom position of the screw thread 4a at the points A and B facing each other in the circumferential direction of the screw thread 4a. After obtaining, you may go ahead of step 27 and step 28. In the illustrated example, the screw gauge is arranged in a posture in which the center line extends in the vertical direction or the horizontal direction to measure the upward or sideways screw hole. May be arranged in a posture that extends in an oblique direction, and the measurement of the screw holes in an oblique direction may be performed.

[0046]

As described above, according to the screw hole measuring device of the present invention, the radial dimension of the screw hole of the workpiece, the effective screw depth and the hole position are adjusted to the change in the distance between the air outlet and the screw thread. Since it is possible to perform automatic measurement on the basis of this, or on the basis of this, and the position of the screw probe contacting the thread, it is possible to perform all of these measurements quantitatively and reduce the man-hours required for the measurement. Further, according to this apparatus, since the measurement can be performed without using the coordinate measuring machine, it is possible to perform the measurement on the line and reduce the man-hour required for setting the work at the time of measurement.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a first screw hole measuring device of the present invention.

FIG. 2 is a configuration diagram illustrating a specific configuration of a pressurized air adjustment circuit and a pressure-voltage conversion circuit used in the device of the above embodiment.

FIG. 3 is a flowchart showing a procedure for measuring a screw hole by the apparatus of the above-described embodiment.

FIG. 4 is an explanatory diagram showing an example of a method of moving the screw gauge to a position facing a screw hole in the apparatus of the above-described embodiment.

FIG. 5 is an explanatory view showing another example of the method of moving the screw gauge to the position facing the screw hole in the apparatus of the above-mentioned embodiment.

FIG. 6 is an explanatory diagram showing an example of a foreign matter detecting method when the screw probe is inserted into the screw hole in the apparatus of the above-described embodiment.

FIG. 7 (a) is an explanatory view showing a method of rotating the screw stylus in the screw hole for one rotation by the apparatus of the above-described embodiment, and FIG. 7 (b) shows the method based on the distance obtained during the rotation. It is explanatory drawing which shows the method of checking the direction and screw hole position where distance becomes the shortest.

FIG. 8 is an explanatory diagram showing a method for obtaining the positions of the apex and the root of a screw thread by the apparatus of the above-described embodiment.

FIG. 9 is a characteristic diagram showing a change state of the voltage output from the pressure-voltage converter when the screw probe is made to enter from the inlet of the screw hole to the vicinity of the hole bottom by the device of the above-described embodiment.

FIG. 10 is an explanatory diagram showing a method for obtaining an effective screw depth of a screw hole by the device of the above embodiment.

FIG. 11 is a configuration diagram showing an embodiment of a second screw hole measuring device of the present invention.

FIG. 12 is a flowchart showing a procedure for measuring a screw hole by the apparatus of the above-described embodiment.

13 (a) and 13 (b) are a sectional view and a front view showing a method for measuring the center position of a screw hole by the device of the above-described embodiment.

14 (a) and 14 (b) are a cross-sectional view and a front view showing a measurement start state of a screw hole dimension of the apparatus of the above-described embodiment.

15 (a) and 15 (b) are a cross-sectional view and a front view showing the state of the device of the above-described embodiment during the first measurement of the screw hole size.

16 (a) and 16 (b) are a cross-sectional view and a front view showing the state of the device of the above-described embodiment during the second measurement of the screw hole size.

FIG. 17 is a side view showing a multi-axis tap hole measuring device as another embodiment of the first screw hole measuring device.

FIG. 18 is an explanatory view showing the internal structure of the measuring head of the device of the above-mentioned embodiment and showing the control system of the device.

FIG. 19 is a sectional view showing a structure of a spindle tip portion and a rod tip portion of the apparatus of the above embodiment.

FIG. 20 is a front view showing a portion of a measuring head and a turret head indexing drive unit of the apparatus of the above-mentioned embodiment.

21 is a view seen from the direction of arrow A in FIG. 20, showing the nipple manifold side of the coupling device of the device of the above embodiment.

FIG. 22 is an explanatory diagram showing an application example of the first and second devices applied to the inspection process of the production facility.

23 (a) to 23 (e) are explanatory views showing an application target of the application example.

24 (a) and 24 (b) are explanatory views showing a method of inspecting the inside of a hole of a workpiece to be inspected in the application example.

FIG. 25 is an explanatory diagram showing inspection results in the above application example.

26A is a plan view showing a limit screw gauge used for measuring a screw diameter and an effective screw depth in a conventional screw hole measuring method, and FIG. 26B is a conventional screw hole measuring method. 3 is an explanatory diagram showing a method of measuring a hole position.

[Explanation of symbols]

 4 Screw hole 4a Thread 5 Thread gauge 5a Air outlet 6 Three-dimensional movement mechanism 9 Pressure-voltage converter 10 Personal computer 11 Controller 14 Probe device

Claims (2)

[Claims] 1. A screw gauge (5) which is inserted into a measured screw hole (4) and blows pressurized air from an air outlet (5a) toward a screw thread (4a) in the screw hole. , A screw gauge moving means (6) for inserting the screw gauge into the screw hole, and rotating and advancing and retracting the screw gauge in the screw hole.
And distance measuring means (9) for outputting a signal corresponding to the distance between the air outlet and the screw thread, based on a change in the back pressure of the pressurized air supplied to the air outlet. Based on the change in the distance obtained during one rotation while the screw head moves in the advancing / retreating direction so as to move the air outlet along the spiral of the screw thread in the screw hole, the distance is A center position measuring means (10) for measuring the shortest or longest direction, and measuring the center position of the screw hole from the distance in the direction and the opposite direction, and the screw probe moving forward and backward in the screw hole. Screw hole measuring means (10) for measuring the inner diameter, the root diameter, and the effective screw depth of the screw hole based on the change in the distance obtained while moving in the direction. apparatus. 2. A screw gauge (5) which is inserted into a measured screw hole (4) and blows pressurized air from an air outlet (5a) toward a screw thread (4a) in the screw hole. , A screw gauge moving means (6) for inserting the screw gauge into the screw hole, and rotating and advancing and retracting the screw gauge in the screw hole.
A contact detection means (14) for detecting contact between the screw probe and the screw thread in the screw hole, and based on a change in back pressure of the pressurized air supplied to the air outlet, Distance measuring means (9) for outputting a signal corresponding to the distance between the air outlet and the screw thread, and the screw measuring element when contacting the screw thread at a plurality of positions in the circumferential direction of the screw hole. A center position measuring means (10) for measuring the center position of the screw hole based on the position, and the screw based on the change in the distance obtained while the screw probe moves in the screw hole in the advancing and retracting direction. A screw hole measuring device comprising: a screw dimension measuring means (10) for measuring a radial dimension of a hole and an effective screw depth.