JP2793921B2 - Drilling method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a small hole mainly by a drill.

[0002]

2. Description of the Related Art In general, a drill for forming a small diameter hole is easily elastically deformed (easy to bend). Problem occurs in that the position of the hole to be machined shifts due to slipping on the surface of the substrate. Also, there is a problem that a small diameter drill has a small elastic limit and is easily broken.

[0003] As a method for solving such a problem, Japanese Patent Application Laid-Open No. 61-244404 discloses a hole Ha to be machined.
As shown in FIG. 13 (a), a deep hole H is formed with a drill 1a shorter than the depth of a hole Ha to be machined, when a deep hole having a depth of 6 times or more the diameter of the drill 1 is formed. Then, as shown in FIG. 13 (b), a method of forming a desired hole Ha so as to match a prepared hole H using a drill 1 having a predetermined length is disclosed. Drill 1a for forming such a prepared hole H
In the above, since the elastic deformation is small, the positional accuracy of the hole Ha is improved. Also, by forming the pilot hole H, an excessive force does not act on the drill 1 and elastic deformation is reduced, so that the chance of breakage is also reduced.

[0004]

In the above-mentioned method, the actual drilling is performed after the pilot hole is formed. Therefore, it is necessary to replace the drill. It is necessary to exactly match the positional relationship between the workpiece and the drill. In other words, it is necessary to use an XY table for positioning the work with a high position accuracy, and there is a problem that the apparatus becomes very expensive.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem. When a drill is formed by aligning a drill with a prepared hole after forming a prepared hole in a work, the positioning is accurately and automatically performed. It is an object of the present invention to provide a hole drilling method and an apparatus therefor.

[0006]

According to the first aspect of the present invention, in order to achieve the above-mentioned object, a drill for pre-machining, which is shorter than the depth of a hole to be machined and has little elastic deformation, is used to lower the surface of the work. After forming a hole, in a hole drilling method that performs cutting using a drill for machining with a length equal to or greater than the depth of the hole, when the tip of the drill for machining is in contact with the vicinity of the pilot hole of the work Of the external force acting on the drill is detected in the plane perpendicular to the axial direction of the drill, and the tip position of the drill is moved in a direction in which the component is reduced.

In the invention of claim 2, at least one of a thrust force acting on the drill and a cutting torque of the drill is detected during cutting by the processing drill,
When the detected value exceeds a predetermined value, the tip of the drill is separated from the work to remove chips, and then cutting is started again. In the invention according to claim 3, at least one of the axial force acting on the drill for preliminary machining and the cutting torque of the drill is detected during the preparation of the prepared hole, and when the detected value is equal to or larger than a predetermined value, the drill is drilled. After the tip is separated from the work to remove chips, cutting is started again.

According to a fourth aspect of the present invention, a spindle motor having a rotating shaft parallel to the drill and driving the drill to rotate, and a spindle motor which is mechanically coupled to the spindle motor at a distance in the circumferential direction of the rotating shaft of the spindle motor to rotate the drill motor. Move the spindle motor straight in a direction substantially along the tangent of the shaft 3
A plurality of actuators, a displacement sensor for detecting displacement due to parallel and rotational movements in a plane orthogonal to the rotation axis of the spindle motor, and an actuator for holding the spindle motor at a predetermined position based on an output of the displacement sensor. Control means for feedback-controlling the movement amount of the drill, the control means detects a change in a component force of an external force acting on the drill in a plane orthogonal to the axial direction of the drill based on a change in a current supplied to the actuator. Then, the position of the spindle motor is adjusted by controlling the current supplied to the actuator so that the component force becomes smaller.

According to the fifth aspect of the present invention, one end is provided via a spindle motor having a rotation axis parallel to the drill and driving the drill to rotate, and a ball joint disposed in a plane perpendicular to the rotation axis of the spindle motor. At least three parallel spindles mechanically coupled to the spindle motor and having, at the other end, a ball joint fixed at a fixed position in another plane orthogonal to the rotation axis of the spindle motor; And at least two actuators for applying a pressing force in a direction intersecting each other in one plane orthogonal to the rotation axis and directed toward the center of the rotation axis of the spindle motor, and orthogonal to the rotation axis of the spindle motor. Sensor that detects displacement due to parallel movement in a plane to be moved, and holds the spindle motor at a predetermined position based on the output of the displacement sensor Control means for feedback-controlling the amount of movement of the actuator, wherein the control means detects a change in a component force of an external force acting on the drill in a plane orthogonal to the axial direction of the drill based on a change in a current supplied to the actuator. This is detected, and the current supplied to the actuator is controlled in such a direction as to reduce the component force to adjust the position of the spindle motor.

According to a sixth aspect of the present invention, a spindle motor having a rotation axis parallel to the drill and rotating the drill is provided, and a suction force is applied to the spindle motor in a plane orthogonal to the rotation axis of the spindle motor. Three or more electromagnets spaced apart in the circumferential direction of the rotation axis of the spindle motor, a displacement sensor for detecting displacement due to parallel movement in a plane perpendicular to the rotation axis of the spindle motor, and an output of the displacement sensor Control means for feedback-controlling the amount of movement of the spindle motor by the electromagnet so as to hold the spindle motor at a predetermined position based on the control signal. Changes in the component force of the external force acting on the drill in the surface to be drilled, and controls the current flowing to the electromagnet in the direction in which the component force is reduced so that the spindle It is to adjust the position of the over data.

According to a seventh aspect of the present invention, a spindle motor having a rotation axis parallel to the drill and driving the drill to rotate, and applying a suction force to the spindle motor in a plane perpendicular to the rotation axis of the spindle motor. Three or more electromagnets spaced apart in the circumferential direction of the rotation axis of the spindle motor, a rotation actuator for rotating the spindle motor around the rotation axis, and an in-plane perpendicular to the rotation axis of the spindle motor A displacement sensor that detects displacement due to parallel and rotational movements in the control unit, and a control unit that performs feedback control on the amount of movement of the spindle motor by the electromagnet and the rotary actuator so as to hold the spindle motor at a predetermined position based on the output of the displacement sensor. Control means, based on the change in the current flowing through the electromagnet, the surface orthogonal to the axial direction of the drill In detecting a change of an external force component force acting on the drill, it is to adjust the position of the spindle motor by controlling the current supplied to the electromagnet the force component in the smaller orientation.

[0012]

According to the method of the first aspect, of the external force acting on the drill when the tip of the drill for machining is in contact with the vicinity of the prepared hole of the drill, a part in a plane orthogonal to the axial direction of the drill is included. Since the tip of the drill is moved in the direction in which the force is reduced, the tip of the drill can be precisely aligned with the center of the pilot hole, increasing the accuracy of the hole position and facilitating the automatic alignment, and In addition, it is possible to prevent the drill from being elastically deformed due to a deviation from the prepared hole, thereby preventing breakage of the drill.

The method of claims 2 and 3 is a preferred embodiment and is the main cause of breakage of the drill before the drill breaks during cutting of the pilot hole or cutting by a working drill. Chips can be removed, and breakage of the drill can be prevented. Further, since the elastic deformation of the drill due to the presence of the chips can be reduced, the machining accuracy of the hole is increased.

According to the constitutions of claims 4 to 7,
A spindle motor having a rotation axis parallel to the drill and driving the drill to rotate; a driving unit for moving the spindle motor at least in parallel in a plane perpendicular to the rotation axis of the spindle motor; and a displacement sensor for detecting a displacement of the spindle motor. Control means for performing feedback control of the movement amount of the drive means so as to hold the spindle motor at a predetermined position based on the output of the displacement sensor, and the control means comprises:
The position of the spindle motor is adjusted by controlling the drive means in a direction in which the component force of the external force acting on the drill is reduced in a plane orthogonal to the axial direction of the drill based on the change in the load on the drive means. The tip is automatically aligned with the center of the pilot hole, eliminating the hassle of positioning. In addition, the hole position accuracy is increased, and the breakage of the drill is prevented, so that it is not necessary to use a high-precision and expensive XY table for the alignment.

[0015]

Embodiment 1 (Embodiment 1) As shown in FIG. 4 , a drilling apparatus basically includes an XY table 11 on which a workpiece is placed, and a housing in a direction orthogonal to the upper surface of the XY table 11. The apparatus main body 10 is provided with a Z table 13 for moving the apparatus 12.

As shown in FIG. 3 , a spindle motor 2 for rotating the drill 1 is housed in the housing 12. Here, a direction in which the housing 12 moves is defined as a Z-axis direction, and one surface orthogonal to the Z-axis direction is defined as an XY plane to define an orthogonal coordinate system. In addition, spindle motor 2
Are arranged so as to coincide with each other in the Z-axis direction. A disk-shaped support plate 3 a orthogonal to the axial direction of the spindle motor 2 is fixed to the outer peripheral surface of the spindle motor 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 motor 2 with the air bearing 3, the spindle motor 2 can be translated and rotated in the XY plane with little frictional force.

A motor holder 4 is inserted into the outer peripheral surface of the spindle motor 2, and movers of linear DC actuators 5 A, 5 B, and 5 C are respectively provided on the outer peripheral surface of the motor 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, and has a cylindrical yoke 5 serving as a stator and a cylindrical shape slidably inserted into a central piece of the yoke 5b. Moving coil 5a
And The movable coil 5a is formed by winding a coil winding around a rectangular cylindrical coil bobbin made of synthetic resin or the like. In addition, permanent magnets (not shown) are provided at appropriate places of the yoke 5b (for example, the inner surfaces of the upper and lower legs in FIG. 3 ) so that the inner surfaces of the two legs and the upper and lower surfaces of the center piece have different magnetic poles. ) Is arranged. 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 motor 2 with the actuators 5A, 5B, 5C. In the radial direction of the rotating shaft of the spindle motor 2, the movable coil 5a
The width of the inner space is set larger than the width of the central piece of the yoke 5b, and the movable coil 5a can move relative to the yoke 5b also in the radial direction of the rotation shaft of the spindle motor 2. Therefore, the position of the spindle motor 2 can be adjusted in a plane orthogonal to the rotation axis by controlling the current supplied to the movable coil 5a of each of the actuators 5A, 5B, 5C. In the configuration of the present embodiment, since the rotation axis of the spindle motor 2 is made to coincide with the Z-axis direction, the position of the tip of the drill 1 is parallelized in a plane parallel to the XY plane by controlling the actuators 5A, 5B, and 5C. It can be moved around and rotated around the Z axis.

The displacement of the spindle motor 2 in a plane parallel to the XY plane, that is, the displacement of the tip of the drill 1 in a plane parallel to the XY plane, is stored in the motor holder 4 by the actuators 5A and 5B. , 5C are detected by displacement sensors 7A, 7B, 7C for detecting the relative distances to the detection pieces 6A, 6B, 6C fixed at the positions corresponding to the positions. The displacement sensors 7A, 7B, 7C include detection pieces 6A, 6B, 6C.
And the displacement sensors 7A, 7B, and 6C, which are optically measuring the distance to the detection pieces 6A, 6B, and 6C.
A device that detects a distance based on the magnitude of eddy current loss by applying a high-frequency electric field from 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. 3 , and the displacement sensors 7A, 7B, and 7C are connected to the actuator 5a.
A, 5B, and 5C are fixed to the yokes 5b. Thus, the ventilation pipe 3b, the yoke 5b, the displacement sensors 7A, 7
B and 7C are mechanically connected to each other,
Fixed to

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 drill 1 can be translated in a plane parallel to the XY plane and can also be rotated around the Z axis. To perform such position control,
As shown in FIG. 5 , based on the displacement amounts detected by the displacement sensors 7A, 7B, 7C, the control circuit 20
What is necessary is just to feedback-control the amount of electricity to the actuators 5A, 5B, 5C. The control circuit 20 takes in the outputs of the displacement sensors 7A, 7B, 7C, outputs an amount of control to the actuators 5A, 5B, 5C, and amplifies the current supplied to the actuators 5A, 5B, 5C. Circuit 20b, displacement sensors 7A, 7
An operation control unit 20c for generating a control amount based on output values of B and 7C, an input unit 20 for setting a target value of the control amount, and the like.
d, a power supply 20e for supplying power to each unit, a driver 20f for driving a feed motor 28 for controlling a feed speed and a moving direction of the Z table 13, and the like are provided. Where 3
Since the control amounts for the actuators 5A, 5B, and 5C need to be set in consideration of the mutual influence, a multivariable matrix operation is required to obtain the control amounts. A microcomputer capable of high-speed operation is used as the operation control unit 20c. Further, as described above, since the spindle motor 2 is supported by the air bearing 3, almost no noise components are generated during the movement, so that the displacement sensors 7A, 7B, 7
No noise component is mixed into the output of C, and this also enables accurate position control.

The actuators 5A, 5B, 5
The driving force F of the movable coil 5a of C is n, the number of turns of the movable coil 5a, the current flowing through the movable coil 5a is I, the magnetic flux density of the permanent magnet is B, and the length of the movable coil 5a in the magnetic field is L.
Then, F = n の I ・ B５L, and the driving force of the movable coil 5a is proportional to the magnitude of the energizing current.
By adjusting the magnitude of the current supplied to each of the movable coils 5a of B and 5C, the compliance can be adjusted.
Further, since the energizing current to each movable coil 5a and the generated force are proportional, the magnitude of the energizing current when the position is held by the feedback control is proportional to the external force. It can be easily detected as a change in current.

The method of forming a hole in a work W such as a printed circuit board using the apparatus having the above configuration is basically the same as the method described in the prior art, and as shown in FIG. A pilot hole is formed using a drill shorter than the depth of the hole to be machined (step 100), and then replaced with a normal drill longer than the depth of the hole to be machined (step 10).
1) A hole is cut (step 102). In the prior art, there was a problem that it was difficult to accurately match the position of the prepared hole with the position of the drill after replacing the drill, but in the present embodiment, in order to solve this problem, As shown in FIG. 2, the change of the component S in the plane parallel to the XY plane with respect to the external force acting on the drill 1 when the tip of the drill 1 comes into contact with the prepared hole H is determined by the actuators 5A and 5A.
B, 5C is detected as a change in the flowing current (step 10).
2) The actuator 5 moves in the direction in which the external force is reduced.
X is controlled by controlling the current supplied to A, 5B and 5C.
The position of the tip of the drill 1 in a plane parallel to the Y plane is adjusted (step 103). Thus, the external force XY
A position where the component S is minimized in a plane parallel to the plane is regarded as a position where the tip of the drill 1 coincides with the center of the prepared hole H, and cutting is performed.

As described above, the actuators 5A, 5B,
Since the position in the plane parallel to the XY plane is adjusted by controlling the 5C conduction current, a highly accurate XY table 11 is not required, and the position of the drill 1 with respect to the prepared hole H is automatically adjusted. Will be. In other words, the cost required for the apparatus can be reduced as compared with the conventional apparatus despite the fact that precise position control can be performed, and the alignment is automated, so that no labor is required.

(Embodiment 2) In this embodiment, as shown in FIGS. 6 and 7, a fixed plate 8 fixed to a housing 12 is provided so as to face a support plate 3a fixed to a spindle motor 2. The fixed plate 8 and the support plate 3a are connected by three or more (here, four) parallel support shafts 8b each having a ball joint 8a at both ends. Therefore, the support plate 3a can move while maintaining the parallel state with the fixed plate 8. Here, if the support plate 3a moves, the distance from the fixed plate 8 changes. However, the movement range in a plane parallel to the XY plane for achieving the object of the present invention is very small. The change in the distance from the fixed plate 8 can be ignored. Two or more actuators 15A and 15B are arranged around the support plate 3a in the circumferential direction so as to be able to press the support plate 3a in the radial direction toward the center of the support plate 3a. Here, both actuators 15A and 15B are arranged so that the driving directions intersect each other. Here, the fixing plate 8 is the housing 1
2, the actuators 15A and 15B are connected to the fixed plate 8 via the arms 8c.

As shown in FIG. 8, the actuators 15A and 15B include a cylindrical movable coil 15a in which a coil winding is wound around a coil bobbin, and a yoke 15b serving as a stator.
And a permanent magnet 15c fixed to the yoke 15b. The yoke 15b has a bottomed cylindrical outer cylinder, and a middle pillar that is integrally erected inside the outer cylinder at the center of the bottom surface of the outer cylinder. A permanent magnet 15c is arranged on the inner peripheral surface of the outer cylinder so as to be cylindrical, and the permanent magnet 15c is magnetized so that the inner peripheral surface of the permanent magnet 15c and the outer peripheral surface of the middle pillar have different magnetic poles. ing. The inner peripheral surface of the permanent magnet 15c is separated from the outer peripheral surface of the middle column, and one end of the movable coil 15a is inserted into this space. Therefore, each of the actuators 15A, 15A
By controlling the current supplied to the movable coil 15a of B, XY
The position of the tip of the drill 1 in a plane parallel to the plane can be adjusted.

Around the support plate 3a, two or more displacement sensors 17A and 17B are fixed via an arm 8d so as to be circumferentially separated from each other and radially opposite to the actuators 15A and 15B. It is fixed to 8. Control circuit 2
At 0, based on the outputs of the displacement sensors 17A and 17B,
The current supplied to the movable coils 15a of the actuators 15A and 15B is feedback-controlled so that the spindle motor 2 is maintained at a predetermined position. Further, a change in the external force acting on the drill 1 when the drill 1 comes into contact with the workpiece W in a plane parallel to the XY plane is detected as a change in the current supplied to the actuators 15A and 15B.

Other configurations and operations are the same as those of the first embodiment, and therefore the description is omitted. (Embodiment 3) In this embodiment, as shown in FIG. 9, instead of the actuators 5A, 5B, and 5C, two straight lines orthogonal to each other in a plane parallel to the XY plane (normally, the X axis direction and the Y axis direction).
Four electromagnets 25A, 25B, 25C, 25D arranged in pairs on the
This embodiment differs from the first embodiment in that two displacement sensors 27A and 27B for detecting displacement in the direction of each straight line are used.

Each electromagnet 25A, 25B, 25C, 25D
Are excited so that those arranged on a straight line form a pair, and the paired electromagnets 25A, 25B, 25C, 25
The spindle motor 2 is positioned by the antagonism of the suction force applied to the spindle motor 2 by D. The attraction force F applied to the spindle motor 2 by each of the electromagnets 25A, 25B, 25C, 25D is represented by I, the current flowing through the coils of the electromagnets 25A, 25B, 25C, 25D, and the electromagnets 25A, 25B, 25C, 25D.
The distance between the motor and the spindle motor 2 is D, and the electromagnets 25A, 2
Assuming that a constant specific to the space between 5B, 25C, 25D and the spindle motor 2 is Q, then F = QI ² / D ^2. It is obtained. Therefore, it is possible to increase compliance. Further, in this embodiment, rotation about the Z axis is not possible, but since the axial direction of the spindle motor 2 is fixed in a direction orthogonal to the XY plane, the Z axis can only be moved in a plane parallel to the XY plane. The same position adjustment range can be obtained without rotating around the axis. The change in the component of the external force acting on the drill 1 in the plane parallel to the XY plane is determined by the electromagnets 25A and 25A.
B, 25C, and 25D can be detected as a change in the current flowing through them. Other configurations and operations are the same as those in the first embodiment, and thus description thereof is omitted.

(Embodiment 4) This embodiment is different from Embodiment 3 in that a rotary actuator 9 for rotating the spindle motor 2 around a rotation axis is loaded as shown in FIG. Further, the displacement sensors 7A, 7B, 7C are arranged so as to be able to detect the distance from the detection pieces 6A, 6B, 6C protruding from the outer peripheral surface of the spindle motor 2 as in the first embodiment.

As shown in FIG. 11, the rotary actuator 9 has a columnar permanent magnet 9b disposed in a cylindrical yoke 9a serving as a stator, and is formed between the yoke 9a and the permanent magnet 9b. It is configured to rotate the cylindrical movable coil 9c in a small range in the space. It goes without saying that the magnetization direction of the permanent magnet 9b and the winding direction of the movable coil 9c are set so that the coil 9c can be rotated by Lorentz force. Such a rotary actuator 9
By using, the spindle motor 2 can be rotated around the rotation axis, so that the tip of the drill 1 can be rotationally moved about the Z axis, which was not possible with the configuration of the third embodiment. Further, if such a rotary actuator 9 is used, it is possible to prevent the spindle motor 2 from trying to rotate due to the reaction force of the torque generated by the rotation of the drill 1, and a change in the torque of the drill 1 is transmitted to the rotary actuator 9. Can be detected by a change in the energizing current. With this configuration, the same position control as that of the first embodiment can be performed. Other configurations and operations are the same as those in the first embodiment, and thus description thereof is omitted.

By the way, in each of the embodiments described above, the position of the pilot hole and the tip of the drill is automatically adjusted when cutting is started. However, after starting cutting, breakage of the drill 1 is prevented. Therefore, it is desirable to perform the following operation. That is, as shown in FIG. 12, it is determined whether the force in the Z-axis direction is equal to or more than a predetermined value (step 10).
5) If there is a risk of breakage, the drill 1 is retracted (step 106), and chips are removed (step 10).
7), the processing is restarted (step 108). When the hole is machined in this way, and the force in the Z-axis direction or the torque around the Z-axis sharply decreases (step 109), the hole machining is terminated assuming that the hole has penetrated. As described above, when there is a possibility that the drill 1 may be broken, the drill 1 is retracted to remove chips which are the main cause of the breakage, and then processing is restarted. You can do it. Further, since the cutting torque is prevented from increasing by removing the chips, it is possible to prevent the positional accuracy of the hole from being lowered by the elastic deformation of the drill 1. Here, the change in the magnitude of the force in the Z-axis direction may be detected based on the change in the load current of the feed motor 28 that drives the Z table 13.

The operation for preventing breakage of the drill 1 during cutting as described above can also be performed when forming a pilot hole. That is, as shown in FIG. 12, a change in the magnitude of the force in the Z-axis direction is detected (Step 110), and when there is a risk of breakage of the drill, the drill is retracted (Step 111) to remove chips. Later (Step 11
2), processing is restarted (step 113). By performing such an operation in the process of forming the pilot hole, it is possible to prevent breakage of the drill for forming the pilot hole and to improve the positional accuracy of the pilot hole. After the preparation of the prepared hole is completed (step 114), the drill may be changed to perform cutting.

The possibility of the breakage of the drill 1 may be determined based on the magnitude of the torque around the Z axis, and the magnitude of the force in the Z axis direction and the magnitude of the torque around the Z axis may be determined. The determination may be made in combination. A change in the magnitude of the torque around the Z axis can be detected by a change in the load current of the spindle motor 2, and in the configuration of the first embodiment, the change in the current supplied to the actuators 5A, 5B, and 5C can be detected. The change can be used, and the configuration of the fourth embodiment can use the change in the current supplied to the rotary actuator 9.

[0034]

According to the method of the first aspect, as described above, of the external forces acting on the drill when the tip of the drill for processing is in contact with the vicinity of the prepared hole of the workpiece, the axial direction of the drill is included. The tip of the drill is moved in a direction that reduces the component force in the plane perpendicular to the hole, so that the tip of the drill can be precisely aligned with the center of the prepared hole, increasing the hole position accuracy and improving the alignment. There is an advantage that automation becomes easy. In addition, it is possible to prevent the drill from being elastically deformed due to a deviation from the prepared hole, thereby preventing breakage of the drill.

According to the method of claims 2 and 3,
While cutting a pilot hole or cutting with a drill for machining,
Chips, which are the main cause of the breakage of the drill, can be removed before the drill breaks, and the breakage of the drill can be prevented. Further, since the elastic deformation of the drill due to the presence of the chips can be reduced, there is an effect that the machining accuracy of the hole is increased.

According to the structure of claims 4 to 7,
A spindle motor having a rotation axis parallel to the drill and driving the drill to rotate; a driving unit for moving the spindle motor at least in parallel in a plane perpendicular to the rotation axis of the spindle motor; and a displacement sensor for detecting a displacement of the spindle motor. Control means for performing feedback control of the movement amount of the drive means so as to hold the spindle motor at a predetermined position based on the output of the displacement sensor, and the control means comprises:
A change in the component force of the external force acting on the drill in a plane orthogonal to the axial direction of the drill is detected based on a change in the load on the driving means, and the driving means is controlled in a direction in which the component force is reduced to control the spindle motor. Since the position of the drill is adjusted, the tip of the drill is automatically adjusted to the center of the prepared hole, so that there is an advantage that it takes no trouble to perform the alignment. In addition, the position accuracy of the hole is increased, and the breakage of the drill is prevented, so that there is no need to use a high-precision and expensive XY table for the alignment.

[Brief description of the drawings]

FIG. 1 is an operation explanatory diagram showing a first embodiment.

FIG. 2 is an operation explanatory diagram of the first embodiment.

FIG. 3 is a partially cutaway perspective view showing the first embodiment.

FIG. 4 is a perspective view of the overall configuration showing the embodiment.

FIG. 5 is a block diagram of a control circuit showing an embodiment.

FIG. 6 is a partially cutaway perspective view showing a second embodiment.

FIG. 7 is a sectional view showing a second embodiment.

FIG. 8 shows an actuator used in the second embodiment,
(A) is a longitudinal sectional view, (b) is a transverse sectional view.

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

FIG. 10 is a partially cutaway perspective view showing a fourth embodiment.

11A and 11B show a rotary actuator used in a fourth embodiment, where FIG. 11A is a plan view and FIG. 11B is a partially cutaway side view.

FIG. 12 is an operation explanatory view showing another operation example of the present invention.

FIG. 13 is a process chart showing a conventional hole drilling method.

[Explanation of symbols]

 Reference Signs List 1 drill 2 spindle motor 3 air bearing 5A actuator 5B actuator 5C actuator 7A displacement sensor 7B displacement sensor 7C displacement sensor 20 control circuit

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B23B 35/00 B23B 47/34 B23B 49/00 B23Q 15/12

Claims (7)

(57) [Claims] 1. A drill for forming a hole having a length equal to or longer than the depth of a hole after forming a pilot hole on the surface of a workpiece using a drill for preliminary processing which is shorter than the depth of the hole to be processed and has less elastic deformation. In the hole drilling method where cutting is performed using a drill, the component force in the plane orthogonal to the axial direction of the drill among the external forces acting on the drill when the tip of the drill is in contact with the vicinity of the prepared hole A hole drilling method comprising: detecting and moving the tip of a drill in a direction in which the component force is reduced. 2. During cutting by a drill for processing, at least one of a thrust force acting on the drill and a cutting torque of the drill is detected. 2. The method according to claim 1, wherein cutting is started again after removing chips from the workpiece. 3. A method for detecting at least one of an axial force acting on a drill for pre-machining and a cutting torque of a drill during cutting of a pilot hole, and detecting a tip of the drill when a detected value is equal to or more than a predetermined value. 3. The method according to claim 1, wherein the cutting is started again after removing the chips by separating the portion from the workpiece. 4. A spindle motor having a rotation axis parallel to the drill and rotating the drill, and a spindle motor which is mechanically coupled to the spindle motor at a distance in a circumferential direction of the rotation axis of the spindle motor, and is substantially connected to a tangent of the rotation axis. Three or more actuators for linearly moving the spindle motor in a direction along the axis, a displacement sensor for detecting displacement due to translation and rotation in a plane perpendicular to the rotation axis of the spindle motor, and a spindle based on the output of the displacement sensor Control means for feedback controlling the amount of movement of the actuator so as to hold the motor at a predetermined position, the control means comprising:
Based on the change in the current flowing through the actuator, the change in the component force of the external force acting on the drill in a plane perpendicular to the axial direction of the drill is detected, and the current flowing through the actuator is controlled in such a direction as to reduce the component force. A hole drilling device characterized in that the position of a spindle motor is adjusted by means of a spindle motor. 5. A spindle motor having a rotation axis parallel to the drill and driving the drill to rotate, and one end mechanically connected to the spindle motor via a ball joint disposed in a plane perpendicular to the rotation axis of the spindle motor. At least three mutually parallel support shafts having, at the other end, a ball joint fixed to a fixed position in another plane perpendicular to the rotation axis of the spindle motor, and a rotation shaft with respect to the spindle motor. At least two actuators that apply a pressing force in a direction intersecting with each other in one plane perpendicular to the center and toward the center of the rotation axis of the spindle motor; A displacement sensor for detecting displacement due to parallel movement, and an actuator for holding the spindle motor at a predetermined position based on the output of the displacement sensor Control means for feedback-controlling the movement amount of the drill, the control means detects a change in a component force of an external force acting on the drill in a plane orthogonal to the axial direction of the drill based on a change in a current supplied to the actuator. A hole drilling device wherein the position of a spindle motor is adjusted by controlling a current supplied to an actuator in a direction in which the component force is reduced. 6. A spindle motor having a rotation axis parallel to the drill and rotating the drill, and a rotation axis of the spindle motor acting on the spindle motor in a plane perpendicular to the rotation axis of the spindle motor. Three or more electromagnets spaced apart in the circumferential direction of the spindle motor, a displacement sensor for detecting displacement due to parallel movement in a plane perpendicular to the rotation axis of the spindle motor, and a spindle motor based on the output of the displacement sensor Control means for feedback-controlling the amount of movement of the spindle motor by the electromagnet so as to keep the spindle at a predetermined position, the control means comprising: The change of the component force of the external force acting on the spindle is detected, and the position of the spindle motor is adjusted by controlling the current supplied to the electromagnet so that the component force decreases. A hole drilling device characterized in that: 7. A spindle motor having a rotation axis parallel to the drill and driving the drill to rotate, and a rotation axis of the spindle motor acting on the spindle motor in a plane perpendicular to the rotation axis of the spindle motor. Three or more electromagnets spaced apart in the circumferential direction, a rotary actuator for rotating the spindle motor around the axis of the rotating shaft, and a parallel movement in a plane orthogonal to the rotating axis of the spindle motor; A displacement sensor for detecting displacement due to rotational movement, and control means for feedback-controlling the amount of movement of the spindle motor by the electromagnet and the rotary actuator so as to hold the spindle motor at a predetermined position based on the output of the displacement sensor. Acts on the drill in a plane perpendicular to the axial direction of the drill based on changes in the current flowing through the electromagnet A hole drilling device which detects a change in a component force of an external force, and controls a current supplied to an electromagnet in a direction in which the component force is reduced to adjust a position of a spindle motor.