JP2966655B2 - Hole position 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 hole position measuring device capable of accurately and automatically measuring the position of a hole formed on the surface of a work.

[0002]

2. Description of the Related Art In general, when measuring the position of a hole formed on the surface of a work, a measuring instrument having a scale such as a ruler or a caliper is often used, and such a measuring operation is performed manually. Become. In the method of manually measuring the position of the hole using a measuring tool, there is a problem that sufficient measurement accuracy cannot be obtained, and it is necessary to be skilled in the work to measure with good reproducibility, and Further, when measuring the positions of holes for a large number of holes and a large number of works, there is a problem that the amount of manual work is extremely large and the working efficiency is low.

Japanese Patent Laid-Open Publication No. Sho 59-14 discloses a method for solving the above-mentioned problem in measuring the position of a hole formed in a work W.
What is described in 8801 gazette is known. As shown in FIG. 11, the apparatus includes a support 30 on which a work W is placed, and rails 3 along both side edges of the support 30.
1 and a configuration in which an inspection rod 33 is attached to a bridge 32 bridged between rails 31. The bridge 32 is attached to the rail 31 so as to be able to travel freely, and the inspection rod 33 is fixed to a carrier 35 that can travel along a rail 34 provided on the bridge 32 along the longitudinal direction. That is, the inspection rod 3
Numeral 3 can be moved to any position along the surface of the support base 30.

As shown in FIG. 12, a test rod 33 is provided with a cylindrical holder 36 fixed to a carrier 35.
And the holder 3 in a direction orthogonal to the surface of the support 30.
6. A hollow spindle 37 inserted to be able to move forward and backward with respect to 6.
A return spring 38 for biasing the spindle 37 in a direction in which the tip is separated from the surface of the support 30; a mandrel 39 inserted into the tip of the spindle 37;
And a return spring 40 that urges the protruding member 7 in a direction to protrude therefrom. A tip 41 of the mandrel 39 is integrally provided with a tracing stylus 41 formed in a tapered conical shape. Also, the spindle 37
Is provided with a switch 42, which is a push button switch to which a pressing force acts from the mandrel 39. When the switch 42 is operated, the coordinate position of the center line of the inspection rod 33 in the coordinate system set in advance on the surface of the support 30 is output to the printer 43.

Therefore, when the inspection rod 33 is moved to the vicinity of the hole H formed in the work W and the spindle 37 is pressed down against the spring force of the return spring 38, as shown in FIG. The center of the tracing stylus 41 coincides with the center of the hole H by being driven into the hole H. In this position,
When a further pressing force is applied to the spindle 37, FIG.
As shown in (b), the mandrel 39 moves relatively to the spindle 37 against the spring force of the return spring 40, and the switch 42 is operated. In short, work W
When the inspection rod 33 is moved to the vicinity of the hole H formed on the spindle 37 and a pressing force is applied to the spindle 37, the position of the hole H is output to the printer 43.

[0006]

With the above configuration, the labor required for measuring the position of the hole H is greatly reduced, and the position of the hole H can be measured with good reproducibility without requiring any skill. However, since the pressing force is manually applied to the inspection rod 33 to press the tracing stylus 41 against the work W, the pressing force on the work W may be excessive and the work W may be deformed. When the material is a material, there is a problem that it is difficult to measure an accurate position of the hole H.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, and when a measurement pin is brought into contact with a work to detect the position of the measurement pin, the work is made of a soft material without deforming the work. Another object of the present invention is to provide a hole position measuring device capable of accurately measuring the position of a hole.

[0008]

According to the first aspect of the present invention, in order to attain the above object, a measuring pin formed in a tapered shape with a front end contacting a workpiece having a center line as a rotationally symmetric axis. Three or more first actuators which are arranged in the circumferential direction of the measuring pin so as to linearly move the measuring pin in different directions substantially along a tangent in the circumferential direction, and linearly move the measuring pin in the center line direction A second actuator, a displacement sensor that detects displacement of the measurement pin due to translation and rotation in a plane parallel to the surface of the work and displacement of the measurement pin due to movement in a direction perpendicular to the surface of the work, Control means for feedback-controlling the amount of movement of the measurement pin by the first actuator and the second actuator so as to hold the measurement pin at a fixed position based on the output of the displacement sensor The control means sets the position of the measurement pin to a position where the external force acting on the measurement pin based on the load current of each actuator is minimized when the tip of the measurement pin is inserted into the hole formed in the work. Set,
This position is determined as the position of the hole.

According to the second aspect of the present invention, the tip of the measuring pin, which is in contact with the workpiece, is formed in a tapered shape whose center line is a rotationally symmetric axis, and the measuring pin is spaced apart in the circumferential direction of the measuring pin. Three or more electromagnets that apply a suction force to the measuring pin in a plane parallel to the surface, an actuator that moves the measuring pin straight in a direction perpendicular to the surface of the work, and an actuator that moves the measuring pin in a direction perpendicular to the surface of the work A displacement sensor that detects displacement of the measurement pin due to parallel movement of the measurement pin and displacement of the measurement pin due to movement in a direction perpendicular to the surface of the workpiece, and an electromagnet that holds the measurement pin in a fixed position based on the output of the displacement sensor. Control means for feedback-controlling the amount of movement of the measurement pin by the actuator, the control means comprising:
When the tip of the measuring pin is inserted into the hole formed in the work, the position of the measuring pin is set to a position where the external force acting on the measuring pin is minimized based on the load current of the electromagnet and the actuator. Determine the position of the hole.

According to the third aspect of the present invention, the measuring pin is formed in a tapered shape whose leading end contacting the work has a center line as a rotationally symmetric axis, and the measuring pin is perpendicular to the direction of the center line of the measuring pin. A support plate coupled in a flange shape, three or more actuators arranged at a distance in the circumferential direction of the measuring pin and configured to linearly move the measuring pin in directions different from each other substantially along a circumferential tangent; Three or more electromagnets, which are arranged in the circumferential direction and are separated from each other in the direction perpendicular to the surface of the work and which are applied to the support plate, and translation and rotation in a plane parallel to the surface of the work A displacement sensor that detects the displacement of the measurement pin due to the displacement of the measurement pin, the linear movement in the direction perpendicular to the surface of the work, and the displacement of the measurement pin due to the inclination with respect to the surface of the work. Control means for feedback-controlling the amount of movement of the measurement pin by the actuator and the electromagnet so as to hold the control pin, wherein the control means is configured to connect the actuator and the electromagnet in a state where the tip of the measurement pin is inserted into a hole formed in the workpiece. The position of the measurement pin is set at a position where the external force acting on the measurement pin is minimized based on at least one load current, and this position is determined as the position of the hole.

[0011]

According to the structure of the first aspect, the measuring pin can be translated and rotated along a plane parallel to the surface of the work, and the measuring pin is moved so as to be able to move in a direction perpendicular to the surface of the work. Since the actuator is held by the actuator, and the actuator is feedback-controlled so as to hold the measurement pin at a fixed position based on the output of the displacement sensor, the actuator acts on the measurement pin by detecting the load current to the actuator. External force can be detected. Based on this load current, the position of the measuring pin is set to the position where the external force acting on the measuring pin is minimized.Therefore, the center line of the measuring pin is positioned with respect to the surface of the work without applying a large external force to the work. The attitude of the measuring pin can be controlled to be vertical. Since this position is determined as the position of the hole in the work, the pressing force is hardly applied to the work, so that the work is not deformed and accurate measurement is possible even if the work is a soft material. It becomes.

According to a second aspect of the present invention, the attitude of the measuring pin is controlled by the electromagnet so that the inclination angle of the measuring pin can be adjusted with respect to the direction orthogonal to the surface of the workpiece, and the direction orthogonal to the surface of the workpiece. The measurement pin is held by an actuator so as to be able to move in parallel to the workpiece. Similar to the configuration of claim 1, the measurement pin is hardly applied to the work and is positioned at the center of the hole formed in the work. With the center lines of the measurement pins aligned, the posture of the measurement pins can be controlled so as to be perpendicular to the surface of the work.

According to a third aspect of the present invention, the measuring pin is moved by an electromagnet so that the inclination angle of the measuring pin can be adjusted in a direction perpendicular to the surface of the work and can be translated in a direction perpendicular to the surface of the work. The measuring pin is held by an actuator so as to be able to hold and translate and rotate the measuring pin along a plane parallel to the surface of the workpiece, and the posture of the measuring pin has six degrees of freedom. Will have. That is, the attitude control of the measuring pin can be performed most accurately, and the measurement accuracy of the position of the hole is increased.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) As shown in FIG. 2, a hole position measuring device basically includes an XY table 11 on which a workpiece is placed and an XY table 1.
Housing 1 which moves in a direction perpendicular to the upper surface of housing 1
The apparatus main body 10 is provided with a Z table 13 for moving the device 2.

In the housing 12, as shown in FIG. 1, a spindle 2 holding a measuring pin 1 and the like are housed. Here, the direction in which the housing 12 moves is Z
An orthogonal coordinate system is defined with one plane orthogonal to the axial direction and the Z-axis direction as an XY plane. The center line of the spindle 2 is Z
It is arranged to match the direction. The measuring pin 1 is formed in a conical shape such that the tip end (lower end) decreases in diameter toward the tip. A disk-shaped support plate 3a orthogonal to the axial direction of the spindle 2 is fixed to the outer peripheral surface of the spindle 2. A pair of ventilation pipes 3b through which compressed air flows are disposed on both sides in the thickness direction of the support plate 3a, and are discharged from an outlet 3c formed on a surface of the ventilation pipe 3b facing the support plate 3a. The support plate 3a is supported by the compressed air while being separated from the two ventilation pipes 3b. Thus, the air bearing 3 is constituted by the support plate 3a and the pair of ventilation pipes 3b. By supporting the spindle 2 with the air bearing 3, the spindle 2 can be translated and rotated in a plane parallel to the XY plane with little frictional force.

A holder 4 is mounted on the outer peripheral surface of the spindle 2, and linear DC actuators 5 A, 5 B, 5 C are respectively provided on the outer peripheral surface of the holder 4 at three locations separated in the circumferential direction.
The movable coil 5a is connected. Each of the actuators 5A, 5B, and 5C is a so-called voice coil motor. As shown in FIGS. 3 and 4, the cross-sectional shape including the tangential direction parallel to the center line of the spindle 2 is a Japanese character. A yoke 5b serving as a stator is provided, and a cylindrical movable coil 5a slidably inserted into a central piece of the yoke 5b. The movable coil 5a is formed by winding a coil winding around a rectangular cylindrical coil bobbin made of a synthetic resin or the like, and the yoke 5b is provided at an appropriate position so that the inner surfaces of both leg pieces and the center piece have different poles. A permanent magnet (not shown) is arranged. For example, permanent magnets may be provided on the inner surfaces of both leg pieces. Therefore, when the movable coil 5a is energized, a Lorentz force proportional to the energizing current is generated, and the movable coil 5a moves in a direction corresponding to the direction of the current. Here, the center piece of the yoke 5b is disposed so as to be substantially along the tangential direction of the coupling position of the spindle 2 with the actuators 5A, 5B, 5C. In the radial direction of the spindle 2, the width of the inner space of the movable coil 5a is set to be larger than the width of the center piece of the yoke 5b.
b. Therefore,
By controlling the current supplied to the movable coil 5a of each of the actuators 5A, 5B, 5C, the position of the spindle 2 can be adjusted in a plane orthogonal to the center line. In the configuration of the present embodiment, since the center line of the spindle 2 is aligned with the Z-axis direction, the actuators 5A, 5B, 5C
With this control, the position of the tip of the measuring pin 1 can be translated in a plane parallel to the XY plane, and can be rotated around the Z axis.

The displacement of the spindle 2 in a plane parallel to the XY plane, that is, the XY of the tip of the measuring pin 1
The amount of displacement in a plane parallel to the plane is determined by displacement sensors 7A, 7B, 7C for detecting relative distances to detection pieces 6A, 6B, 6C fixed to holder 4 at positions corresponding to actuators 5A, 5B, 5C. Is detected by Displacement sensor 7
A, 7B, and 7C include those for optically measuring the distance from the detection pieces 6A, 6B, and 6C, and the detection pieces 6 made of metal.
A sensor that detects a distance based on the magnitude of eddy current loss by applying a high-frequency electric field to the sensors A, 6B, and 6C from the displacement sensors 7A, 7B, and 7C can be used.

The above-described vent pipe 3b and actuator 5
The yokes 5b of A, 5B, and 5C are integrally coupled with the yoke 5b on the upper ventilation pipe 3b in FIG. 1, and the displacement sensors 7A, 7B, and 7C are connected to the actuator 5a.
A, 5B, and 5C are fixed to the yokes 5b. The ventilation pipe 3b is connected to the cylindrical air bearing 8 via the arm 8a. The air bearing 8 is externally inserted into a pair of guide shafts 8 b disposed in the axial direction (Z-axis direction) of the spindle 2 and fixed to the housing 12, and discharges compressed air to the inner peripheral surface of the air bearing 8. The inner peripheral surface of the air bearing 8 and the outer peripheral surface of the guide shaft 8b can be moved in the axial direction of the guide shaft 8b while being separated from each other. Therefore, the spindle 2 can move in the Z-axis direction, that is, in the direction of the center line, with almost no frictional force.

A movable coil 9a of a linear DC actuator 9 which advances and retreats in the axial direction of the spindle 2 is connected to the end face of the spindle 2 opposite to the measurement pin 1 in the axial direction (Z-axis direction). The yoke 9b serving as the stator of the actuator 9 is formed in a cylindrical shape, and is different from the above-described actuator 5 except that the shape is different.
A, 5B, and 5C have the same configuration. A detection piece 6D is fixed to the end of the spindle 2, and a displacement sensor 7D is provided at a position facing the detection piece 6D so that the displacement of the detection piece 6D in the axial direction of the spindle 2 can be detected. That is, the displacement sensor 7D can detect the displacement of the spindle 2 in the Z-axis direction. The yoke 9b of the actuator 9 and the displacement sensor 7D are fixed to the housing 12. Here, in the actuator 9 having the above configuration, the force in the Z-axis direction is determined according to the magnitude of the current supplied to the movable coil 9a, and the amount of movement cannot be controlled. The reaction force received by the pin 1 from the workpiece W and the downward pressing force of the actuator 9 are antagonized, and the output of the actuator 9 is antagonized to the spring force of a spring (not shown) having one end fixed to the housing 12. Thereby, the movement amount is controlled. The actuator 9 may have a structure that generates two forces that antagonize in the Z-axis direction. As this type of actuator, Z
A mover is arranged between a pair of electromagnets separated in the axial direction,
There is a structure in which the position of the mover is set to an arbitrary position by adjusting attraction and repulsion between each electromagnet and the mover.

According to the above configuration, the actuator 5
By controlling the amount of current supplied to the movable coils 5a of A, 5B, and 5C, the tip of the measuring pin 1 can be translated in a plane parallel to the XY plane and can be rotated around the Z axis. . Further, by controlling the amount of current supplied to the movable coil 9a of the actuator 9, parallel movement in the Z-axis direction can be performed. To perform such position control, as shown in FIG. 5, the displacement sensors 7A, 7B, 7C,
7D based on the amount of displacement detected.
In the above, the amount of current supplied to the actuators 5A, 5B, 5C, 9 may be feedback controlled. The control circuit 20 takes in the outputs of the displacement sensors 7A, 7B, 7C, 7D and outputs an amount of control to the actuators 5A, 5B, 5C, 9; an interface 20a which outputs the amounts of control to the actuators 5A, 5B, 5C, Amplifying circuit 2 that drives 9
0b, the position of the hole is calculated based on the output values of the displacement sensors 7A, 7B, 7C, 7D and the actuator 5
A control unit 20c for generating a control amount for A, 5B, 5C, 9 and an output unit 20 for outputting a measurement result of a hole position
d, a power supply 20e for supplying power to each unit, and a feed motor 21 provided in the apparatus main body 10 for moving the housing 12 in the Z-axis direction (instructing movement of the housing 12 and controlling a feed speed) according to a control amount. Driver circuit 20f, etc., which is driven by Here, since the control amounts for the four actuators 5A, 5B, 5C and 9 need to be set in consideration of the mutual influence, a multivariable matrix operation is required to obtain the control amounts. In order to satisfy this requirement, a microcomputer capable of high-speed operation is used as the operation control unit 20c. Further, as described above, the spindle 2 is supported by the air bearing 3 in a plane parallel to the XY plane, and is guided by the air bearing 8 when moving in the Z-axis direction. Yes, displacement sensors 7A, 7B, 7C,
No noise component is mixed in the output of 7D, and this also enables accurate position control.

The actuators 5A, 5B, 5
The driving force F of the movable coils 5a and 9a of C and 9 is n, the number of turns of the movable coils 5a and 9a is I, the current flowing through the movable coils 5a and 9a is I, the magnetic flux density by the permanent magnet is B, and the movable coil 5a in the magnetic field is , 9a is L, then F = n ・ I ・ B ・ L. Since the driving force of the movable coils 5a, 9a is proportional to the magnitude of the energizing current, each actuator 5
By adjusting the magnitude of the current supplied to each of the movable coils 5a, 9a of A, 5B, 5C, and 9, the compliance can be adjusted. In particular, since the compliance of the measuring pin 1 in the thrust direction can be adjusted by the actuator 9, the compliance can be controlled by the material of the work W. Further, since the current flowing through each of the movable coils 5a and 9a is proportional to the generated force, the magnitude of the current flowing when the position is held by the feedback control is proportional to the external force, and the change in the external force To actuators 5A, 5B, 5C, 9
Thus, it can be easily detected as a change in the current flowing through the power supply.

The procedure for detecting the position of a hole formed in the surface of the workpiece W, which is the object to be measured, using the apparatus having the above configuration is as follows. Here, it is assumed that a reference hole is formed on the surface of the work W. First, the position of the reference hole formed on the surface of the work W is measured, and the center line of the measurement pin 1 is determined based on the relative position of the target hole to the reference hole (this positional relationship is known at the time of design). The XY table 11 is moved so that is positioned substantially at the center of the target hole. Thereafter, the position of the target hole is measured and output to the output unit 20d.

Measurement of the positions of the reference hole and the target hole is as follows.
This is performed according to the procedure shown in FIG. That is, substantially coincide with the center C ₁ of the hole H and the center line C ₂ of the measuring pin 1 as shown in FIG. 7 (a), the lowers the housing 12 by the Z table 13 as shown in FIG. 7 (b) Move the tip of measuring pin 1 to work W
Into the hole H formed in the hole. At this time, measuring pin 1
The external force acting on the measuring pin 1 is detected in a plane parallel to the XY plane acting on (1) (S1). This external force can be detected by a change in the current (load current) applied to the actuators 5A, 5B, and 5C, and controls the current applied to the movable coil 5a of the actuators 5A, 5B, and 5C in a direction in which the external force decreases. Measuring pin 1 in a plane parallel to the XY plane
Is adjusted (S2). In short, measuring pin 1
The tip position of the measuring pin 1 is adjusted so as to minimize the external force acting in the plane parallel to the XY plane, and such adjustment adjusts the hole as shown in FIG. The center c _{1 of} H and the center line c ₂ of the measurement pin 1 can be matched. Since the housing 12 is continuously lowered by the Z table 13, the measuring pin 1 receives a reaction force from the workpiece W. When the reaction force increases, the measuring pin 1 rises relatively to the housing 12, so that
This displacement is detected by the displacement sensors 7A, 7B, 7C to detect an increase in the reaction force (S3). When the increase in the reaction force is detected, the measurement is terminated and the pressing force on the work W is released (S3).
4). As described above, since the measurement is terminated when the increase in the reaction force is detected, the deformation of the work W can be prevented. In addition, since a large pressing force is not required for measuring the position of the hole H, the position of the hole H can be accurately measured even with a workpiece W made of a soft material.

(Embodiment 2) In this embodiment, as shown in FIG. 8, instead of actuators 5A, 5B and 5C, X
Four electromagnets 15A, 15B, 15C, 15 arranged in pairs on two straight lines (usually set in the X-axis direction and the Y-axis direction) orthogonal to each other in the Y plane
Using D and detecting displacement in the direction of each straight line 2
This embodiment differs from the first embodiment in that the displacement sensors 17A and 17B are used.

Each electromagnet 15A, 15B, 15C, 15D
Are excited so that the magnets arranged on a straight line form a pair, and the electromagnets 15A, 15B, 15C, 15
The spindle 2 is positioned by the antagonism of the suction force applied to the spindle 2 by D. The attractive force F applied to the spindle 2 by each of the electromagnets 15A, 15B, 15C, 15D is
The current flowing through the coils of B, 15C and 15D is I, the distance between the electromagnets 15A, 15B, 15C and 15D and the spindle 2 is D, and the space between the electromagnets 15A, 15B, 15C and 15D and the spindle 2 is unique. If the constant is Q, F = QI ² / D ^2. If the distance D is reduced, a very large suction force can be obtained. Therefore, it is possible to increase compliance. In this embodiment, rotation about the Z axis is not possible.
Is fixed in a direction orthogonal to the XY plane, the same position adjustment range can be obtained only by parallel movement in the XY plane without rotating around the Z axis. When measuring the positions of the holes, the electromagnets 15A, 15B, 15C,
What is necessary is just to detect the external force acting on the measuring pin 1 by the change of the load current of 15D. Other configurations and operations are described in the first embodiment.
The description is omitted here.

(Embodiment 3) In this embodiment, as shown in FIG. 9, a support plate 3a is used instead of the air bearing 3 in the embodiment 1.
The pair of electromagnets (3A, 3D), (3B, 3) arranged on a straight line in the Z-axis direction on both sides in the thickness direction of
E) and (3C, 3F) are provided in three sets spaced apart in the circumferential direction of the spindle 2. Each electromagnet 3A, 3B, 3
C, 3D, 3E, and 3F act on the support plate 3a by applying a suction force in the Z-axis direction.
A, 3D), (3B, 3E), and (3C, 3F) hold the support plate 3a at a predetermined position by an antagonistic action.
That is, the electromagnets 3A, 3B, 3C, 3D, 3E, 3F
By adjusting the suction force, the position of the support plate 3a in the Z-axis direction and the inclination with respect to the Z-axis (that is, the amount of rotation about the X-axis and the Y-axis) can be adjusted. Further, since the spindle 2 can be held without contacting other members, the spindle 2 can move with little frictional force.

The movable coils 5a of the actuators 5A, 5B and 5C are respectively mounted on one surface in the thickness direction of the support plate 3a (the lower surface in FIG. 9) at three places separated in the circumferential direction.
Are connected via Therefore, similarly to the first embodiment,
By the actuators 5A, 5B, and 5C, parallel movement of the spindle 2 in the X and Y directions and rotational movement about the Z axis can be performed.

The amount of displacement due to the parallel movement of the spindle 2 in a plane parallel to the XY plane and the rotational movement about the Z axis is determined by the detection piece 6A fixed to the support plate 3a at a position corresponding to each of the actuators 5A, 5B, 5C. , 6B, 6C are detected by displacement sensors 7A, 7B, 7C. Further, the displacement amount due to the parallel movement of the spindle 2 in the Z-axis direction and the rotational movement around the X-axis and the Y-axis is:
The displacement is detected by displacement sensors 7D, 7E, and 7F that detect relative distances from three positions in the circumferential direction of the support plate 3a. The electromagnets 3A, 3B, 3C, 3D, 3E, 3F, the yokes 5b of the actuators 5A, 5B, 5C, and the displacement sensors 7A, 7B, 7C, 7D, 7E, 7F are housed 12
Fixed against.

According to the above configuration, the electromagnets 3A, 3B,
By controlling the amount of electricity to the coils of 3C, 3D, 3E, and 3F, parallel movement in the Z-axis direction and rotational movement around the X-axis and Y-axis can be performed, and the actuators 5A, 5B, 5
By controlling the amount of current supplied to the movable coil 5a of C, parallel movement in the XY plane and rotational movement about the Z axis can be performed. When controlling the position, as shown in FIG. 10, the displacement sensors 7A, 7B, 7
Based on the displacements detected by C, 7D, 7E, and 7F, the amounts of current to the electromagnets 3A, 3B, 3C, 3D, 3E, and 3F and the actuators 5A, 5B, and 5C may be feedback-controlled.

The measuring pin 1 is connected to the electromagnets 3A, 3B, 3C, 3
Except for support by D, 3E, and 3F, the configuration and operation are the same as those of the first embodiment. By replacing the measuring pin 1 in the above embodiment with a drill bit and replacing the spindle with a motor for rotating the drill bit,
It can also be used to detect the position of a pilot hole during drilling. In addition, although the example in which the shape of the tip portion of the measuring pin 1 is conical has been shown, other shapes such as a spherical shape or a pyramid shape may be used.

[0031]

According to the present invention, as described above, the measuring pin is held by the actuator or the electromagnet so that the measuring pin can be translated in at least a plane parallel to the surface of the workpiece. Since the load current to the actuator and the electromagnet is feedback controlled so that the position is maintained, the external force acting on the measuring pin can be detected by detecting the load current to the actuator and the electromagnet. . Based on this load current, the position of the measuring pin is set to the position where the external force acting on the measuring pin is minimized.Therefore, the center line of the measuring pin is positioned with respect to the surface of the work without applying a large external force to the work. The attitude of the measuring pin can be controlled to be vertical. Since this position is used as the position of the hole of the work, the pressing force hardly acts on the work, so that the work is not deformed, and accurate measurement is possible even if the work is a soft material. It has the advantage that. In addition, an actuator and an electromagnet are provided so as to enable parallel movement of the measuring pin in a direction perpendicular to the surface of the work, and a displacement sensor for detecting the displacement of the measuring pin in the same direction is provided. It is possible to control so that the pressing force does not act excessively, which can also prevent deformation of the work.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a first embodiment.

FIG. 2 is a perspective view of the overall configuration showing the embodiment.

FIG. 3 is a plan view of an actuator used in the embodiment.

FIG. 4 is a sectional view of an actuator showing an embodiment.

FIG. 5 is a block diagram of a control circuit used in the first embodiment.

FIG. 6 is an operation explanatory diagram showing the embodiment.

FIG. 7 is a process diagram showing a process of forming a pilot hole according to the embodiment.

FIG. 8 is a partially cutaway perspective view showing the second embodiment.

FIG. 9 is a partially cutaway perspective view showing a third embodiment.

FIG. 10 is a block diagram of a control circuit used in a third embodiment.

11A and 11B show a conventional hole position measuring device, wherein FIG. 11A is a plan view and FIG. 11B is a front view.

12A and 12B show a conventional inspection rod, in which FIG. 12A is a partially cutaway side view showing a state before contact with a work, and FIG. 12B is a partially cutaway side view showing a state at the time of contact with a work. .

FIG. 13 is an operation explanatory view of a conventional hole position measuring device.

[Explanation of symbols]

 1 Measurement pin 2 Spindle 5A Actuator 5B Actuator 5C Actuator 5D Actuator 5E Actuator 5F Actuator 7A Displacement sensor 7B Displacement sensor 7C Displacement sensor 7D Displacement sensor 7E Displacement sensor 7F Displacement sensor 9 Actuator 15A Electromagnet 15B Electromagnet 15C Electromagnet 17D Electromagnet 15D Electromagnet 17D Sensor 20 control circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G01B 21/00-21/32 G01B 7/00-7/34 G01B 5/00-5/30

Claims (3)

(57) [Claims] A measuring pin formed in a tapered shape with a tip portion in contact with a workpiece having a center line as a rotationally symmetric axis;
Three or more first actuators which are arranged in the circumferential direction of the measuring pin so as to linearly move the measuring pin in different directions substantially along a tangent in the circumferential direction, and linearly move the measuring pin in the center line direction A second actuator, a displacement sensor that detects displacement of the measurement pin due to translation and rotation in a plane parallel to the surface of the work and displacement of the measurement pin due to movement in a direction perpendicular to the surface of the work, Control means for feedback-controlling the amount of movement of the measurement pin by the first actuator and the second actuator so as to hold the measurement pin at a fixed position based on the output of the displacement sensor; Where the external force acting on the measuring pin is minimized based on the load current of each actuator when the part is inserted into the hole formed in the workpiece. Set the position of Teipin, hole position measuring device and determines the position and location of the hole. 2. A measuring pin formed in a tapered shape with a tip portion in contact with a workpiece having a center line as a rotationally symmetric axis.
Three or more electromagnets, which are arranged in the circumferential direction of the measuring pin and are separated from each other in the plane parallel to the surface of the work, to apply a suction force to the measuring pin, and move the measuring pin straight in a direction perpendicular to the surface of the work. An actuator to be moved, a displacement sensor for detecting displacement of the measurement pin due to parallel movement in a plane parallel to the surface of the work and displacement of the measurement pin due to movement in a direction perpendicular to the surface of the work, and an output of the displacement sensor. Control means for feedback-controlling the amount of movement of the measurement pin by the electromagnet and the actuator so as to hold the measurement pin in a fixed position based on the measurement pin.The control means is such that the tip of the measurement pin is inserted into a hole formed in the work. The position of the measurement pin is set to a position where the external force acting on the measurement pin is minimized based on the load current of the electromagnet and the actuator in the Hole position measuring apparatus characterized by determining the location. 3. A measuring pin formed in a tapered shape with a tip portion in contact with a workpiece having a center line as a rotationally symmetric axis.
A support plate coupled in a flange shape perpendicular to the center line direction of the measurement pin with respect to the measurement pin, and arranged differently in the circumferential direction of the measurement pin and different from each other so that the measurement pin substantially follows the tangent in the circumferential direction. Three or more actuators that move linearly in the direction, three or more electromagnets that are arranged in the circumferential direction of the measuring pin and that act on the support plate in a direction perpendicular to the surface of the work, and A displacement sensor for detecting displacement of the measuring pin due to translation and rotation in a plane parallel to the surface of the workpiece, and for detecting linear displacement in the direction perpendicular to the surface of the work and displacement of the measurement pin due to the inclination with respect to the surface of the work, and a displacement sensor Control means for feedback-controlling the amount of movement of the measurement pin by the actuator and the electromagnet so as to hold the measurement pin in a fixed position based on the output of the control pin, The position of the measuring pin is set to a position where the external force acting on the measuring pin is minimized based on the load current of at least one of the actuator and the electromagnet in a state where the tip of the constant pin is inserted into the hole formed in the work. A hole position measuring device, wherein the position is determined as a hole position.