JP2929913B2 - Screw hole measuring device - Google Patents

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 an apparatus for automatically measuring a radial dimension, an effective screw depth, and a hole position.

[0002]

2. Description of the Related Art Conventionally, when the above-described measurement is performed, the thread diameter and effective thread depth of a screw hole are determined by a gauge and a stop gauge as shown in FIG. And screwed into the screw hole alternately by hand.If the gauge can be screwed to the specified effective thread depth and the stop gauge can not be screwed, it is measured that it is within the tolerance range. As shown in FIG. 11 (b), measurement is performed by touching the shaft of a screw gauge 2 manually screwed into a screw hole with a probe 3 of a general-purpose three-dimensional measuring machine to determine the position of the shaft. I was going by the way.

[0003]

However, in such a conventional method for measuring a screw hole, the measurement of the screw diameter and the effective screw depth is performed using the limit screw gauge 1 and depending on human senses. There is a problem that quantitative measurement is impossible and the number of steps required for the measurement increases.In addition, the measurement of the hole position cannot be performed unless the work is set on the coordinate measuring machine. However, there is a problem that it is impossible in terms of measurement and the number of steps also increases in the measurement.

In recent years, pressurized air is blown from an air outlet toward an object to be measured, and a change in the back pressure of the pressurized air is measured. An air micrometer for measuring a distance is known, and by using the air micrometer, a distance to an object can be quantitatively measured in a non-contact manner.

[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 using the above-described principle of the air micrometer. The first screw hole measuring device is inserted into the screw hole to be measured, and blows pressurized air from an air outlet toward a screw thread in the screw hole. A screw tracing stylus moving means which is inserted into a screw hole to rotate and move back and forth in 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 between the crest and the screw measuring element moving in the reciprocating direction so as to move the air outlet in the screw hole along the spiral of the screw thread; Of the distance obtained during one rotation A center position measuring means for examining the direction in which the distance becomes the shortest or the longest, and measuring the center position of the screw hole from the distance and the distance in the direction opposite thereto; and And a screw size 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.

Further, a second screw hole measuring device of the present invention comprises:
A screw probe that is inserted into the measured screw hole and blows out pressurized air from an air outlet toward a thread in the screw hole; and a screw hole that inserts the screw probe into the screw hole. Screw measuring element moving means for rotating and reciprocating within the screw, contact detecting means for detecting that the screw measuring element and the screw thread in the screw hole are in contact with each other, and pressurized air supplied to the air outlet Distance measuring means 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 screw hole, and contacting the screw thread at a plurality of circumferential positions of the screw hole A center position measuring means for measuring a center position of the screw hole based on the position of the screw measuring element, and a change in the distance obtained while the screw measuring element moves in the forward and backward directions in the screw hole. , The radial dimension of the screw hole, the effective screw depth and A screw size measurement means for measuring is made comprises a.

[0007]

In the first device, the screw measuring element moving means first moves the screw measuring element to a position roughly aligned with the screw hole to be measured, and then inserts the screw measuring element into the screw hole. Rotating and reciprocating in the screw hole, during the rotation and reciprocating movement in the screw hole, the screw measuring element blows out pressurized air from an air outlet toward a screw thread in the screw hole,
Thereby, the distance measuring means outputs a signal corresponding to the distance between the air outlet and the thread based on the change in the back pressure of the pressurized air supplied to the air outlet, and measures the center position. The means is based on a change in the distance obtained during one rotation while moving in the reciprocating direction so that the screw probe moves the air outlet in the screw hole along the spiral of the thread, The direction in which the distance is the shortest or the longest is checked, and the center position of the screw hole is measured from the direction and the distance in the opposite direction. 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 during the movement in the forward and backward directions.

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

In the above-mentioned second device, the screw-measuring element moving means first moves the screw-measuring element to a position roughly aligned with the screw hole to be measured, and then inserts the screw-measuring element into the screw hole. In the direction perpendicular to the axis of the screw hole in the screw hole,
Move until the contact detecting means detects the contact between the screw measuring element and the screw thread in the screw hole, and contact the screw measuring element with the screw thread at a plurality of positions in the circumferential direction of the screw hole. The center position measuring means measures the center position of the screw hole based on the position of the screw measuring element, and then the screw measuring element moving means rotates and moves the screw measuring element within the screw hole, and During rotation and retraction in the hole,
The screw measuring element blows out pressurized air from the air outlet toward the thread in the screw hole, whereby the distance measuring means changes the back pressure of the pressurized air supplied to the air outlet. And outputs a signal corresponding to the distance between the air outlet and the screw thread based on the distance, and the screw dimension measuring means determines the distance obtained while the screw probe moves in the screw hole in the reciprocating direction. The diameter of the screw hole in the radial direction and the effective screw depth are measured based on the change of the screw hole.

[0010] Therefore, according to the second device, the radial dimension, effective screw depth and hole position of the screw hole of the work are determined by the position of the screw measuring element in contact with the screw thread, and the air outlet and the screw thread. Automatic measurement can be performed based on the change in the distance between the three-dimensional measuring machine and the measuring machine. Since the measurement can be performed without using, the measurement on the line can be performed, and the man-hour required for setting the work at the time of the measurement can be reduced.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of a first screw hole measuring device of the present invention. The device of this embodiment is for measuring various dimensions and hole positions of a screw hole 4 of a work. a is a screw measuring element 5 having an air supply port 5a on the side face, it may be rotated to any angle to the center line C _d around with may be moved to any position the screw measuring element 5 to the three-dimensional directions A three-dimensional moving mechanism 6 composed of, for example, a tool moving mechanism of a normal NC machine tool as a threaded measuring element moving means, and pressurized air supplied from a pressurized air supply source 7 such as an air line of a factory. A pressurized air adjustment circuit 8 that adjusts and supplies the air to the air outlet 5a of the screw gauge 5 is interposed between the pressurized air adjustment circuit 8 and the air outlet 5a, and is supplied to the air outlet 5a. Distance measurement means that converts the change in back pressure of pressurized air into a change in voltage and outputs it Pressure-
An ordinary personal computer as a center position measuring means and a screw dimension measuring means for converting a voltage converter 9 and an output voltage of the pressure-voltage converter 9 into digital values and measuring various dimensions of a screw hole based on the values. (A so-called personal computer) 10 and a controller 11 having a normal microcomputer, for example, of the NC machine tool for numerically controlling the operation of the three-dimensional moving mechanism 6 based on a signal from the personal computer 10. .

Here, for example, as shown in FIG. 2, the pressurized air adjusting circuit 8 includes an on-off valve 8a, a submicron air filter 8b, an oil mist separator 8c, a regulator 8d, and a pressure reducing valve 8e. The pressure-voltage converter 9 can be configured by connecting two circuits 9a and 9b for branching the supplied pressurized air, as shown in FIG. Both sides of the pressure-sensitive diaphragm of the differential pressure detecting section 9c are connected via a throttle valve 9d, respectively, and one of the circuits 9a is opened to the atmosphere through a throttle valve 9e, and 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 a change in the capacitance due to the displacement of the pressure-sensitive diaphragm, a change in the resistance value of the resistor constituting the bridge, and the like. (Not shown) that outputs as a voltage change It can be constituted by providing a vessel. Since the screw measuring element 5 rotates, an air circuit is connected between the air outlet 5a of the screw measuring element 5 and the circuit 9b while allowing the screw measuring element 5 to rotate. It is connected by a formula coupler.

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 the predetermined position, first, in step 21, the three-dimensional moving mechanism 6 is operated by the controller 11 by a signal from the personal computer 10, and the screw measuring element 5 is inserted into the screw hole 4. facing a center line C _d of the center line C _h and screw gauge head 5 of the screw hole 4 is moved to the position corresponding schematic, screw measuring element 5
Can be inserted into the screw hole 4 without interfering with the screw thread 4a of the screw hole 4.

Here, the movement to the position facing the screw hole 4 is based on data given in advance when the positioning accuracy of the work is sufficiently high, and the screw hole in the design is determined based on the positioning position of the work. Screw measurer 5 at position 4
May 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 the screw measuring element 5 is fitted into the reference hole 12 whose diameter is slightly larger than 5, the screw measuring element 5 is positioned at the position of the screw hole 4 in the design based on the position of the reference hole 12.
Is automatically moved.

When the positioning accuracy of the work is not so high, the screw tracing stylus 5 to the position facing the screw hole 4
May be moved by the method shown in FIGS. 4 and 5,
In the method shown in FIG. 4, air outlets 5 b are provided diagonally downward toward the four directions at the lower end of the screw measuring element 5, and the screw measuring element is positioned at the position of the screw hole 4 in design with reference to the work positioning position. 5 is automatically moved, 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, after the position correction, since the distance between the four air outlet 5b of each and the screw hole 4 of the inlet of the chamfer 4b are equal, the center line C _d threaded screws feeler 5 consistent with relatively high accuracy to the center line C _h of the hole 4, thus, upon insertion into the screw holes 4, screw measuring element 5 and the screw thread
Interference with 4a can be reliably prevented.

In the method shown in FIG.
An air outlet 5c is provided downward at the lower end of the screw hole, and the screw tracing stylus 5 is automatically moved to the design screw hole 4 position based on the work positioning position, and then supplied to the air outlet 5c. while the change in voltage due to the change in the back pressure of the pressurized air is measured for a screw measuring element 5 to the center line C _d perpendicular two directions, moved across a screw hole 4, as indicated by the arrow In each of these two directions, the position where the voltage is lowest, that is, the position where the back pressure of the pressurized air is lowest because the distance between the air outlet 5c and the work is the maximum, is determined, 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, since modifying the position of the screw measuring element 5 by using the actual position of the center line C _h of the screw hole 4 determined, the center line of the center line C _d screw hole 4 of the screw measuring element 5 _Ch with a relatively high degree of accuracy, and therefore also in this method, when inserted into the screw hole 4, the thread gauge 5 and the thread 4 a
Interference can be reliably prevented.

After moving the screw tracing stylus 5 to the position facing the screw hole 4 as described above, here, in step 22,
The three-dimensional moving mechanism 6 is operated by the controller 11 according to a signal from the personal computer 10 and
1 is inserted into the screw hole 4 to an intermediate depth close to the inlet of the hole but to such a degree that the pressurized air from the air outlet 5c does not leak out of the hole. When a foreign object is clogged in the screw hole 4, the screw probe 5 is inserted by the insertion.
In order to prevent damage to the screw, in an actual device, as shown in FIG. 6, the screw tracing stylus 5 is usually supported by the holder 6a of the three-dimensional moving mechanism 6 so as to be able to be retracted into the inside thereof. In this case, when the screw stylus 5 is retracted, the supply port 6b of the pressurized air to the air outlet 5a is preferably retracted as shown in the drawing. Provide at the position where it is closed. With this configuration, when the screw tracing stylus 5 is retracted by contact with the foreign matter 13 in the screw hole 4 due to the insertion, the back pressure of the pressurized air for screw hole measurement abnormally increases due to the closing of the supply port 6b. As a result, the voltage change also shows an abnormal rise, so that the contact of the screw measuring element 5 with the foreign matter 13 can be easily known without being detected by a separate sensor or switch. By separately providing a sensor and a switch on the device 5, the electric wiring can be prevented from becoming complicated.

When the screw gauge 5 is inserted into the screw hole 4 to an intermediate depth close to the entrance, here, step 23 is executed.
Then, the three-dimensional moving mechanism 6 is operated by the controller 11 in response to a signal from the personal computer 10 and, for example, the NC
As shown in FIG. 7 (a), the screw stylus 5 is moved from the insertion position indicated by the solid line in the drawing to the position indicated by the imaginary line in the drawing by one pitch of the thread 4a by a program similar to the rigid tapping function of the machine tool. (P) The air outlet 5a is moved by one pitch along the helix of the screw thread 4a while being moved in the direction of entry while making one rotation in synchronization with the movement. The air outlet 5a and the screw thread 4a along the spiral of the screw thread 4a for one pitch, which the converter 9 continuously outputs.
The change in the voltage corresponding to the change in the distance between them is checked by the personal computer 10 to find the direction of the screw stylus 5 at which the voltage is maximized.

Here, the back pressure of the pressurized air increases as the distance between the air outlet 5a and the thread 4a becomes shorter, because the resistance of the pressurized air blown out from the air outlet 5a increases. It is known that the increase in the back pressure increases the output voltage of the pressure-voltage converter 9, and that the change in the distance and the change in the output voltage have a substantially linear relationship. Accordingly, the direction of the screw tracing stylus 5 at which the voltage is maximized is such that the distance between the air outlet 5a and the screw thread 4a is shortest, as shown in FIG. 7B. If the output voltage value is converted into a distance by a personal computer 10 using a conversion table or a conversion formula obtained in advance by a test, the air outlet
The distance between 5a and the thread 4a, and thus the position of the portion 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 so that the screw tracing stylus 5 is oriented in the shortest distance direction and is kept in that direction. As shown in FIG.
Move in the approach direction by 2 to 3 pitches (P) of the thread 4a,
As shown in FIG. 9, a voltage change corresponding to a 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, is used by the personal computer 10. Investigating and calculating the average value of the maximum value M during the voltage change into the distance to obtain the vertex position of the thread 4a, and converting the average value of the minimum value m during the voltage change into the distance The root position of the screw thread 4a is obtained by the calculation, and the peak position and the root position of the screw thread 4a at the point A in the circumferential direction of the screw thread 4a shown in FIG.

In the next step 25, the controller 11 activates the three-dimensional moving mechanism 6 by a signal from the personal computer 10 to rotate the screw tracing stylus 180 °, thereby turning the air outlet 5a in the opposite direction. Orientation, that is, the direction in which the distance between the air outlet 5a and the screw thread 4a is the longest, in the following step 26, in the same manner as in step 24, the top position of the screw thread 4a is determined and the root of the screw thread 4a is determined. The position is determined, and thus the thread shown in FIG.
Thread 4a at point B in the circumferential direction of 4a, rotated 180 ° from point A
The vertex position and the valley bottom position of are calculated. Here, the points A and B oppose each other in the diameter direction of the screw hole 4. In step 27, the personal computer 10 calculates the inner diameter d of the screw hole 4 shown in FIG. 1, which is the distance between the vertices of the screw thread 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 three-dimensional moving mechanism 6 is operated by the controller 11 in response to a signal from the personal computer 10, so that the screw tracing stylus 5 is designed, as shown in FIG. after entering the two pitches position deeper than the value L _d, from the position, for example, it is moved to the retracted direction to one pitch position shallower than the design value L _d, the pressure during its movement - voltage converter As shown in FIG. 9, the personal computer 10 checks the voltage change corresponding to the change in the distance between the air outlet 5a and the screw thread 4a, which is continuously output by the personal computer 10, and the air outlet 5a and the screw thread The distance between the root and the root of 4a falls within a predetermined range based on the dimensional tolerance with respect to the distance based on which the root diameter D was previously obtained, that is, the height of the thread 4a maintains the predetermined height. Find the maximum penetration depth of exit 5a and The depth and effective thread depth L.

In the last step 29, a midpoint between the apex position or the valley bottom position of the thread 4a at the points A and B is obtained. Such midpoint, the threaded hole 4 centerline C _h
, 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 screw depth L, and the hole position of the screw hole 4 of the work are determined between the air outlet 5a and the screw thread 4a. Since automatic measurement can be performed based on a change in distance, all of those measurements can be performed quantitatively, and the number of steps required for the measurement can be reduced. Further, according to this apparatus, since measurement can be performed using a normal NC machine tool without using a three-dimensional measuring machine, measurement can be performed on a work processing line, and it is necessary to set a work at the time of measurement. Man-hours 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 drawing, the same parts as those shown in FIG. 1 are denoted 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. The screw measuring element 5 having the air outlet 5a on the side and the screw measuring element 5 are used. together may be moved to an arbitrary position to the three-dimensional directions can be rotated to any angle to the center line C _d around, as the screw feeler moving means, for example, the three-dimensional movement comprising a conventional NC machine tool moving mechanism A mechanism 6 and a pressurized air adjusting circuit 8 for appropriately adjusting pressurized air supplied from a pressurized air supply source 7 such as an air line of a factory and supplying the pressurized air to an air outlet 5a of the screw gauge 5
A distance which is interposed between the pressurized air adjusting circuit 8 and the air outlet 5a, converts a change in back pressure of pressurized air supplied to the air outlet 5a into a change in voltage, and outputs the voltage. A pressure-voltage converter 9 as a measuring means, and a center position measuring means and a screw dimension measuring means for converting an output voltage of the pressure-voltage converter 9 into a digital value and measuring various dimensions of a screw hole based on the value. A general personal computer (personal computer) 10 and a controller 11 for controlling the operation of the three-dimensional moving mechanism 6 based on signals from the personal computer 10, for example, the NC machine tool having a normal microcomputer. And a probe device as contact detection means for detecting that the screw probe 5 has come into contact with the 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 screw tracing stylus 5 to move in parallel or tilt relative to the device 14 by contacting the screw thread 4a. At the same time, the screw measuring element 5 is elastically supported by a known support mechanism so that the screw measuring element 5 is returned to a predetermined home position with respect to the device 14 when the contact is lost. Contact with the thread 4a is detected by a piezoelectric element or the like that detects the operation of the supporting mechanism, or is detected from the electrical continuity between the thread gauge 5 and the thread 4a. The signal of is output. Further, although the screw measuring element 5 rotates, its rotation angle is at most 360 degrees, so that the screw measuring element 5 rotates 360 degrees between the air outlet 5a of the screw measuring element 5 and the circuit 9b. Are connected by an air hose (not shown) of an appropriate length which connects the air circuit while permitting the air flow.

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, the controller 11 activates the three-dimensional moving mechanism 6 by a signal from the personal computer 10 based on, for example, data given in advance, and performs the screw measurement. child 5, opposed to the screw hole 4, is moved to a position where the center line C _d of the center line C _h and screw gauge head 5 of the screw hole 4 is roughly aligned, from the position, in FIG. 13 (a) As shown, the screw tracing stylus 5 is advanced and inserted into the screw hole 4 to a position slightly inserted from the entrance thereof without interfering with the screw thread 4a in the screw hole 4.

Next, in step 32, the three-dimensional moving mechanism 6 is operated by the controller 11 according to a signal from the personal computer 10, and the screw stylus 5 is moved 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 four directions perpendicular to the axis of the screw hole and perpendicular 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 probe 5 has come into contact with the thread 4a, the screw probe 5 is moved. After stopping, the personal computer 10 obtains the positions of the screw tracing stylus 5 that have been corrected for the movement of the response time at the time of contact with the screw thread 4a in the above four directions, respectively. The center position of the screw hole 4 is obtained by calculating the center position of the circle inscribed by the surface, and it is checked whether or not the center position is within a predetermined tolerance to determine whether or not the center position is acceptable.

Next, in step 33, the three-dimensional moving mechanism 6 is operated by the controller 11 in response to a signal from the personal computer 10, and the screw stylus 5 is moved to the position shown in FIG.
As shown in (a) and (b), after once moving to the screw hole center position, the controller 11 operates the three-dimensional moving mechanism 6 by a signal from the personal computer 10 in a subsequent step 34, Fig. 15 (b)
As shown in the figure, in the air blowing direction in which the air outlet 5a faces, the air outlet corresponds to the inner diameter of the screw hole 4.
Move until 5a and thread 4a approach to a predetermined distance,
During the movement, in order to prevent runaway of the screw gauge 5, air is blown out from the air outlet 5 a, and the personal computer 10 monitors the voltage converted from the air pressure by the pressure-voltage converter 9.

If the air pressure exceeds the allowable value due to the air outlet 5a of the screw gauge 5 being too close to the thread 4a during the movement, the process proceeds from step 35 to step 36, After stopping the movement of 5 and investigating the cause of the excessive approach, removing the cause, the screw measuring element 5 is returned to the screw hole center position again, and the process returns to step 34. Thus, for example, when the actual inner diameter of the 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 a foreign matter is attached to the screw thread, the above movement causes excessive interference. It is possible to effectively prevent the screw probe 5 and the screw thread 4a from being broken. If only the inside diameter of the screw hole is to be checked, the inside diameter of the screw hole can be obtained from the position at the time of contact with the thread 4a of the screw tracing stylus 5 determined in step 32.

On the other hand, if the air pressure does not exceed the allowable value during the movement, the process proceeds from step 35 to step 37, where the controller 11 activates the three-dimensional moving mechanism 6 by the signal from the personal computer 10. Then, as shown by the arrow in FIG. 15 (a), the screw tracing stylus 5 is moved in the tap depth direction, that is, in the hole bottom direction, and air is blown out from the air outlet 5a during the movement. The 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 first screw hole measurement is performed, and then, in step 38, the three-dimensional moving mechanism 6 is operated by the controller 11 by a signal from the personal computer 10,
The screw measuring element 5, back into the screw hole center position, 180 degrees to invert the center line C _d around at that position.

Thereafter, as shown in FIG.
In the same manner as in steps 34 to 36 described above, while preventing runaway of the screw stylus 5, the screw stylus 5 is moved in the air blowing direction so that the air outlet 5 a and the thread 4 a correspond to the inner diameter of the screw hole 4. Move until it approaches the predetermined distance, then step 42
Then, in the same manner as in the above step 37, the screw tracing stylus 5 is
(A) As shown by the middle arrow, move in the direction of the screw hole entrance,
During the movement, air is blown out from the air outlet 5a, 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. Thereby, the second screw hole measurement is performed. Then, in step 43, the three-dimensional moving mechanism 6 is operated by the controller 11 by the signal from the personal computer 10 so that the screw measuring element 5 is connected to the screw hole 4. While moving outside, the data of the voltage change state obtained by the two screw hole measurements is
Compared with a graph or a relation table showing the relationship between the distance between the screw thread and the air outlet 5a and the voltage, which were separately obtained, based on, for example, the average value of the above two measurement data, the actual effectiveness of the screw hole 4 The diameter and the effective screw depth are obtained, and these are compared with the set values to determine whether or not the size of the screw hole 4 is acceptable.

Therefore, according to the apparatus of this embodiment, the effective diameter, effective screw depth and hole position of the screw hole 4 of the work are automatically determined based on the change in the distance between the air outlet 5a and the screw thread 4a. Since it can be measured, all of those measurements can be performed quantitatively, the man-hours required for the measurement can be reduced, and a normal NC machine tool can be used without using a three-dimensional measuring machine. Measurement can be performed on the work processing line, and the number of steps required for setting the work at the time of measurement can be reduced.

FIG. 17 shows another embodiment of the first apparatus of the present invention, in which a plurality of tap holes can be simultaneously measured by using an NC turret machine capable of mounting a plurality of machining heads having a multi-axis cutting tool. The figure shows a multi-axis tap hole measuring apparatus as an embodiment, and the same parts as those in the above-described embodiment are denoted by the same reference numerals.

An NC turret machine serving as a backbone 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 on which up to four processing heads can be mounted, is indexed and rotated, and is located at a predetermined indexing position for processing on the left side in FIG. Position one,
The plurality of tools mounted on the processing head positioned at the indexing position are simultaneously rotated and driven, and the turret head indexing drive unit 50 indexes and rotates the turret head 49 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 perpendicular to each other to perform the positioning and cutting feed of the tool of the machining head located at the predetermined indexing position.

In this embodiment, using such an NC turret machine, simultaneous processing of a plurality of tap holes, cleaning and air blowing in those holes, and inspection of the tap holes are performed in the same process. 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, and a measuring head 55 having a rotation transmitting structure similar to those processing heads.

FIG. 18 is an explanatory view showing the internal structure of the measuring head 55 and a control system of the apparatus of this embodiment. The head body of the measuring head 55 is composed of 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 one driven shaft 60, and these spindles 59 are driven shafts.
When the measuring head 55 is located at the predetermined indexing position, the driven shaft 60 is driven by the main shaft drive motor 63 in the turret head 49 via the main shaft coupling 62 when the measuring head 55 is located at the predetermined indexing position. It is drive-coupled to a main shaft 64 that is driven to rotate. The operation of the spindle drive motor 63 is controlled by a 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 accommodated in each of the spindles 59 so as to be able to move forward and backward and to rotate integrally with the spindle 59. Each rod 65 is constantly urged in the forward direction by a spring 66. In addition, the cap 67 prevents the spindle 59 from slipping out of the spindle 59, and further has an air passage extending to the tip inside the spindle 59. As shown in FIG. 19, a screw measuring element 5 having an air outlet 5a at the end thereof is mounted on the distal end of the rod 65, and a rod in the spindle 59 is attached to each screw measuring element 5.
A rotary joint (rotary coupler) mechanism 68 is formed in the center case 57 of the measuring head 55 to individually supply pressurized air for measurement via 65, and pressurized air adjustment to the rotary joint mechanism 68 is performed. The supply of pressurized air from the circuit 8 can be performed via a coupling device 69.

FIG. 20 and FIG.
21, each processing head 52-54 and measuring head
The turret head indexing drive unit 50 includes a coupling manifold 70 fixed to the side surface of the turret head indexing drive unit 50 and a nipple manifold 72 driven by a cylinder 71, the nipple manifold 72 moving forward. The coupling manifold 70 of any of the heads 52 to 55 located at the predetermined indexing position
Here, each coupling manifold 70 is provided with a fluid required by a corresponding head, that is, a cutting oil for cooling and air for an air curtain in a drill head 52 and a tap head 53, and cleaning / cleaning. The air blow head 54 is provided only with a port for supplying cutting oil for cleaning and air blow, and the measurement head 55 is provided only with a port for supplying pressurized air for measurement, while the nipple manifold 72 has respective heads 52 to An air curtain port 72a, a cutting oil port 72b, an air blow port 72c, and a measurement pressurized 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. Connected to the pressurized air adjustment circuit 8 and a cutting oil supply source (not shown).

According to such an apparatus, the tap holes extending in the horizontal direction as shown in FIG. 19 are obtained by the same procedure as that of the flow chart shown in FIG. 3 for the above-mentioned embodiment of the first apparatus. Measurement of the center position, radial dimension and effective screw depth of 4 can be performed simultaneously for a plurality of tap holes 4, and the measurement time of those tap holes is greatly reduced as compared with the case of measuring one by one. Since the tap hole processing, air cleaning and inspection can be performed in the same process, quality control can be performed for each processing station.
A particularly effective production system can be constructed for a mass production line of about 10,000 units per month.

The rod 65 is accommodated in the spindle 59 so as to be able to move forward and backward, and is always urged by the spring 66 because the tap hole to be measured is clogged with a damaged 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 tapped hole, and the screw stylus 5 in contact with the foreign matter or the hole during the feed movement is retracted, the screw stylus 5 is retracted. In this way, the thread gauge 5 is protected from the above-mentioned processing failure. Further, here, in order to detect these processing defects, a detection dock 74 is provided at the rear end of each rod 65, and the rod 65 by retracting each screw measuring element 5 is attached to the head main body of the measuring head 55. A sensor 75 for detecting the retreat of the detection dock 74 is fixed, and the retreat signal output from the sensor 75 is transmitted to the personal computer 10 via a non-contact multipoint transmitter 76.
Is input to Therefore, according to this apparatus, it is possible to automatically detect processing defects such as breakage of a cutting tool, clogging of a tap hole due to cutting chips, and a large displacement of a hole position, while protecting the screw measuring element 5 therefrom. Can also.

FIG. 22 shows a case where the present invention is applied to an inspection process of a production facility.
This shows an application example of the first and second devices of the present invention. In this example, the screw measuring element 5 is directly connected to an NC machine 81 capable of performing contouring feed described later in correspondence with the first device. 23 or is mounted via a sensor capable of detecting contact with a workpiece corresponding to the second device, and a casting cavity, a crack or the like in a hole of a casting coarse material shown in FIG. Foreign matter, hole shapes such as splines, serrations, and snap ring grooves shown in FIG. 4B, missing rollers and balls of the bearing shown in FIG. 4C, valve seats and bearing outer races shown in FIG. (E)
It is used for inspection of burrs and the like of the intersection holes shown in FIG.

More specifically, after the work 82 to be inspected is positioned and fixed at a predetermined position of the NC machine 81, as shown in phantom lines in FIG. 22 and as shown in FIG. It is inserted into the hole 82a of the work 82 to be inspected,
In the hole 82a, the screw measuring element 5 is fed by contouring. That screw gauge head 5, as indicated by arrows in solid line in FIG. 24, when rotation in its own centerline C _d around the same time,
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 is used to
Since it is possible to scan the inside of a completely, for example, if there are nests, cracks, foreign matter, etc., they are automatically detected as a change in the back pressure of the measurement air as shown in FIG. It can also detect the size of such nests, cracks, foreign matter, etc., and the hole shapes such as the above-mentioned splines, serrations, snap ring grooves, missing rollers and balls of bearings, valve seats and bearing outers. Poor seating of races, burrs at intersection holes, etc. can also be detected automatically and easily.

Preferably, the inner diameter of the air outlet 5a is set to 1
And a gap between the inner wall surface of the hole 82a and the air outlet 5a.
0.1 to 0.2 mm and pressurized air pressure is 0.2 to 0.5 kg / cm ²
Then, nests, cracks, foreign matter, and the like can be detected with a high sensitivity of about 10 μm.

Although the present invention has been described based on the illustrated example, the present invention is not limited to the above example. For example, in step 23 in FIG. 3, the direction indicating the minimum voltage, that is, the direction in which the distance is the longest is determined. The process of obtaining the hole position in step 29 may be performed by the procedure up to step 26 in which the vertex position or the root position of the thread 4a at the points A and B facing each other in the circumferential direction of the thread 4a is determined. After it is determined, it may be performed before step 27 or step 28. In the illustrated example, the screw measuring element is arranged in such a position that its center line extends in the vertical or horizontal direction to measure upward or horizontal screw holes. May be arranged in a posture extending in an oblique direction, and the oblique screw holes may be measured.

[0046]

As described above, according to the screw hole measuring device of the present invention, the radial dimension, effective screw depth and hole position of the screw hole of the work can be changed by changing the distance between the air outlet and the screw thread. Automatic measurement can be performed based on or based on the position of the thread measuring element in contact with the thread, so that all of those measurements can be performed quantitatively and the number of steps required for the measurement can be reduced. Further, according to this apparatus, since measurement can be performed without using a three-dimensional measuring machine, measurement can be performed on a line, and the number of steps required for setting a work at the time of measurement can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one 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 apparatus of the embodiment.

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

FIG. 4 is an explanatory view showing an example of a method of moving a screw measuring element to a position facing a screw hole in the apparatus of the embodiment.

FIG. 5 is an explanatory view showing another example of a method of moving a screw measuring element to a position facing a screw hole in the apparatus of the embodiment.

FIG. 6 is an explanatory diagram showing an example of a foreign matter detection method when a screw stylus is inserted into a screw hole in the apparatus of the embodiment.

FIG. 7A is a diagram illustrating a method in which the screw measuring element is caused to make one rotation while entering a screw hole by the apparatus of the above embodiment, and FIG. 7B is a diagram illustrating the method based on a distance obtained therebetween. It is explanatory drawing which shows the direction in which a distance becomes the shortest, and the method of investigating a screw hole position.

FIG. 8 is an explanatory diagram showing a method for obtaining the positions of the top and the bottom of a thread by using the apparatus of the above embodiment.

FIG. 9 is a characteristic diagram illustrating a change state of a voltage output by the pressure-voltage converter when the screw tracing stylus is advanced from the entrance in the screw hole to the vicinity of the hole bottom by the apparatus of the above 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 one 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 embodiment.

FIGS. 13A and 13B are a cross-sectional view and a front view showing a method of measuring the center position of a screw hole by the device of the above embodiment.

FIGS. 14A and 14B are a cross-sectional view and a front view showing a state in which measurement of a screw hole size is started in the apparatus of the embodiment.

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

FIGS. 16A and 16B are a cross-sectional view and a front view showing a state during the second measurement of the screw hole size of the apparatus of the embodiment.

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 diagram showing an internal structure of a measuring head of the device of the embodiment and a control system of the device.

FIG. 19 is a cross-sectional view showing a structure of a spindle tip and a rod tip of the device of the above embodiment.

FIG. 20 is a front view showing a measuring head and a turret head indexing drive unit of the apparatus according to the embodiment.

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

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

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

FIGS. 24A and 24B are explanatory diagrams 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 an inspection result in the application example.

FIG. 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. FIG. 4 is an explanatory diagram showing a method of measuring a hole position among them.

[Explanation of symbols]

 Reference Signs List 4 Screw hole 4a Screw thread 5 Screw gauge 5a Air outlet 6 Three-dimensional moving mechanism 9 Pressure-voltage converter 10 Personal computer 11 Controller 14 Probe device

Continuation of front page (56) References JP-A-2-10105 (JP, A) JP-A-1-224608 (JP, A) JP-A-64-54209 (JP, A) (58) Fields studied (Int .Cl. ⁶ , DB name) G01B 13/00-13/24

Claims (2)

(57) [Claims] A screw probe (5) inserted into a screw hole (4) to be measured and blowing out pressurized air from an air outlet (5a) toward a screw thread (4a) in the screw hole; A screw-measuring element moving means (6) for inserting the screw-measuring element into the screw hole and rotating and moving back and forth in the screw hole;
A distance measuring means (9) for outputting a signal corresponding to a distance between the air outlet and the screw thread based on a change in back pressure of pressurized air supplied to the air outlet; The distance is determined based on a change in the distance obtained during one rotation while the screw probe moves in the reciprocating direction so as to move the air outlet in the screw hole along the spiral of the screw thread. A center position measuring means (10) for examining the shortest or longest direction and measuring the center position of the screw hole from the distance and the distance in the opposite direction; A screw hole measuring means (10) for measuring an inner diameter, a root diameter, and an effective screw depth of the screw hole based on the change in the distance obtained while moving in the direction. apparatus. 2. A screw probe (5) inserted into a screw hole (4) to be measured and blowing out pressurized air from an air outlet (5a) toward a screw thread (4a) in the screw hole. A screw-measuring element moving means (6) for inserting the screw-measuring element into the screw hole and rotating and moving back and forth in the screw hole;
Contact detection means (14) for detecting that the screw measuring element and the screw thread in the screw hole are in contact with each other; and, based on a change in back pressure of pressurized air supplied to the air outlet, A distance measuring means (9) for outputting a signal corresponding to a distance between an air outlet and the screw thread; and a thread measuring element for contacting the screw thread at a plurality of circumferential positions of the screw hole. A center position measuring means (10) for measuring a center position of the screw hole based on a position, and the screw based on a change in the distance obtained while the screw probe moves in the forward and backward directions in the screw hole. A screw hole measuring device comprising: a screw size measuring means (10) for measuring a radial dimension of a hole and an effective screw depth.