JPH07251353A - Collision prevention device - Google Patents

Abstract

PURPOSE:To provide a device capable of momentarily detecting the collision between the main spindle vicinity of a machine, including an attachment and a tool holder in a machining center, and conductive work to alarm-stop the machine. CONSTITUTION:A ring sensor 16 is provided, so as to surround a main shaft ram 7, on the lower end surface of a main shaft head 6, and the coat of electric insulating material is provided on the straight shunk part of a tool TA to insulate between a tool holder 22 and a tool. When any of the main shaft ram 7, an attachment 14, and the tool holder 22 contacts work W during cutting, an alternating current supplied from an A.C. power source 17 flows in the center part of the ring sensor 16 to output a fine signal from a ring gauge. The signal is amplified by an amplifying part 18 to output an alarm signal to alarm-stop a machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle attachment of a machine tool such as a machining center and a spindle of a machine including a tool holder, when the workpiece comes into contact with a workpiece or is about to come into contact with the workpiece.
The present invention relates to a collision prevention device that stops an alarm of a machine to avoid damage due to a collision.

[0002]

2. Description of the Related Art In recent years, machining programs for performing complicated machining such as die machining in a machining center or the like have often been created by using an automatic program generator such as CAD / CAM. Machining programs created by this automatic programming machine are often loaned to subcontractors from parent companies such as automobile manufacturers.These machining programs differ in the spindle quill or spindle ram dimensions and tool holders that differ depending on the type of machine used. There is almost no consideration for the shape of
For example, as shown in FIGS. 14 and 15, when the work W is being scraped by moving the spindle quill 101 or the tool holder 102 along the X axis or the Y axis, when the workpiece W is further moved to completely scrape the uncut portion 103, the spindle quill 101 is removed. Or tool holder 1
02 may collide with the wall surface of the work W.

In addition, a program creation error and a data error when transferring the processed data to the NC tape may be overlapped, so that it is not known where the collision occurs until the image is actually moved.

Therefore, a complete machining program without a collision accident is only a machining program with a proven machining record or a checked machining program in which the operator checks each one by idle operation one by one, but a huge sequence. Checking a machining program consisting of the following is a waste of time without cutting chips, so it is unrealistic in terms of profitability and unmanned operation at night, etc., is limited to machining programs with a proven track record, and the first product machining is done by the operator. Currently, processing is performed while arranging each one and monitoring it.

Conventionally, there are the following prior arts developed to avoid a collision accident due to such an unchecked machining program. (1) The collision prevention device known in JP-A-62-99047 is provided with an air ejector for ejecting air around the mechanical structure 104 as shown in FIG. 16, and collects the reflected sound of the ejected air. A micro controller 105 is provided, and a drive controller that analyzes a reflected sound and outputs a control signal for approaching an obstacle is provided.

(2) A device for preventing interference between an attachment and a workpiece in a machine tool known in Japanese Utility Model Publication No. 61-117645 is a workpiece W of an attachment 106 attached to a spindle of a machine tool as shown in FIG. The electric conductor 107 is attached to a portion that may interfere with each other through an easily deformable insulating piece, and the interference between the attachment 106 and the workpiece W is detected by the electrical contact between the electric conductor and the workpiece to stop the machine. It is a thing.

(3) The arbor collision prevention device for a machine tool known in Japanese Utility Model Laid-Open No. 63-182836, as shown in FIG. 18, makes contact with the outer surface of the arbor 108 to contact a contacted object and generate a detection signal. The detector 109 is provided so that the machine is stopped when the detection signal of the contact detector is input to the control circuit 110.

(4) An ultrasonic collision device for a machine tool known in Japanese Patent Laid-Open No. 62-152640 is a super-machine for detecting the distance to an obstacle in the moving direction of the spindle head 111 of the machine tool as shown in FIG. When the distance detected by the sound wave device 112 is within a predetermined distance, the movement of the spindle head is stopped and the alarm lamp is driven.

(5) A collision prevention device known from Japanese Utility Model Laid-Open No. 62-168239 discloses an object sensing device 114 and a winding device of the object sensing device on a ram portion 113 of a vertical machine tool as shown in FIG. A device 115 is provided, and an object detection device is projected by a fast-forward mode command of the machine to detect the approach of the object, and the machine is stopped or the feed speed of the machine is decelerated, and the object is detected so as not to come into contact with the workpiece during machining. The device is wound by a winding device and stored in a spiral shape.

[0010]

According to Japanese Patent Laid-Open No. 62-99047 described in the prior art, it is expected that cutting fluid or cutting chips will be applied to the microfon 105, and frequent cleaning is performed to remove the influence. Will be required. 61-117
No. 645 causes a malfunction when cutting chips enter between the electric conductor 107 attached to the attachment 106 and the workpiece 107 and become conductive.

Similarly, in Japanese Utility Model Laid-Open No. 63-182836, a malfunction occurs due to conduction due to cutting chips, and it is necessary to provide a contact detection unit 109 for each arbor. Japanese Patent Laid-Open No. 62-1526
No. 40 and No. 62-168239 are not compatible with attachments.

In addition, JP-A-62-99047, JP-A-61-117645 and JP-A-63-18283.
No. 6 has a problem that it is necessary to protect and clean the contact portions of the respective wirings or pipes when the attachment, the tool arbor, etc. are removed from the spindle.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a spindle ram, an attachment, a tool holder, etc. for a machine such as a machining center when machining a machine tool such as a machining center. An object of the present invention is to provide a collision preventing device that avoids damage due to a collision by stopping an alarm of a machine when a work around the main shaft is about to come into contact with a work or at a moment when the work comes into contact with the work.

[0014]

In order to achieve the above object, the collision prevention device according to the present invention prevents collision between the periphery of a machine spindle including an attachment and a tool holder and a work including a conductive mounting setup during machining. A device to prevent
A detector provided on the spindle head so as to surround a spindle ram or a spindle sleeve, which obtains a signal by an alternating current passing through the center portion when it comes into contact with the work around the spindle of the machine, and a machine based on the output signal of the detector. To stop the alarm, a power supply that supplies a weak AC current to the machine, and the tool holder provided on the surface of the shank part of the cutting tool that is attached to the main spindle of the machine or the attachment spindle via the tool holder, and the cutting tool is insulated. It comprises an electric insulating material.

Further, the detector may be provided on the ram type spindle head so as to surround the main spindle of the machine.

Further, an electric insulating material is provided on the tool holding surface of the tool holder.

An electrical insulating material is provided on the inner surface or the outer surface of the straight collet.

Further, a conductive protective cover is provided at a portion including the spindle attachment and the tool holder, which is likely to interfere with the work around the spindle of the machine.

[0019]

According to the first aspect of the present invention, for example, in a portal machining center, while the cutting work is performed using the tool electrically insulated from the tool holder, the spindle ram, the attachment,
When any of the tool holders comes into contact with the work, the AC current supplied from the AC power source flows through the center of the detector provided at the lower end of the spindle head, and a signal is output from the detector to stop the machine alarm.

According to a second aspect of the present invention, for example, the detector provided at the lower end of the ram type spindle head of the vertical or horizontal machining center detects the contact and stops the alarm.

According to the third and fourth aspects of the present invention, the electrical insulation material provided on the tool holding surface of the tool holder or the inner surface or the outer surface of the straight collet insulates the tool holder from the tool, and the circumference of the work and the spindle of the machine during cutting with a normal tool. The contact with is detected by the detector.

According to a fifth aspect of the present invention, the machine is stopped by an alarm in response to a signal from a detector when a work is contacted with a protective cover such as a conductive rubber provided on a portion around the main shaft where the work is likely to interfere.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment In the portal machining center of FIG. 1, a table 2 is placed on a bed 1 installed on the floor so as to be movable and positionable in the X-axis (front-back) direction, and columns 3 are provided on both floors of the bed 1.
A and 3B are erected. The top beam 4 is fixed on the columns 3A and 3B, and the cross beam 5 having a guide in the Y-axis direction is mounted on the guides in the Z-axis (vertical) direction provided on the front side surfaces of the columns 3A and 3B so as to be movable and positionable. Has been done.

A spindle head 6 is movably positioned on a guide of the cross beam 5 in the Y-axis direction, and a spindle ram 7 or a spindle quill is provided on the spindle head 6 so as to be movable and positioned in the Z-axis direction.
A main body spindle 8 is rotatably supported by the main spindle ram 7.

Further, an attachment automatic exchange device (not shown) is attached to the rear side of the table 2, and various attachments automatically attached to and detached from the lower end surface of the main spindle ram 7 by the attachment automatic exchange device are attached to the attachment spindle shown in FIG. Is the angular attachment 13 that faces the horizontal direction, and the attachment spindle shown in FIG.
An extension attachment 14 concentrically oriented in the vertical direction, a universal attachment 15 in which the attachment main shaft shown in FIG. 8 is rotatable in the horizontal direction and the vertical direction, and the like are prepared.

A ring sensor 16 is attached to the lower end surface of the spindle head 6 so as to surround the spindle ram 7. As the ring sensor 16, for example, an LC touch sensor manufactured by Daishowa Kikai can be used. This is a coil wound around an annular core, and an alternating voltage is induced in the coil when an alternating (high frequency) current flows through the center.

The block diagram portion of FIG. 1 is a control circuit for alarming the machine by the alternating voltage induced in this coil. The AC power supply 17 is a power supply that supplies a weak AC current to the machine body of the machining center. The amplification unit 18 is a portion that amplifies the output signal (AC voltage) of the ring sensor. The alarm signal output part 19 is a part for outputting an alarm signal by the amplified AC voltage. The alarm stop execution part 21 is a part for stopping the alarm of the machine by an alarm signal. W is a conductive work fixed on the table 2 via a conductive mounting jig (not shown).

As shown in FIG. 6, the tool holder 22 detachably attached to the main spindle 8 of the machine or the attachment main spindle holds various tools with a straight shank through a taper collet 23a built in a tool holder main body 23 as shown in FIG. As shown in FIG. 6, the tool has a coating of the electric insulating material 25 on the outer peripheral gripping surface and the rear end surface of the straight shank portion Ta of the ball end mill TA and the flat end mill TB. As the electric insulating material, a water-soluble paint or an emulsion resin paint may be applied by electrodeposition in addition to coating of an electric insulator such as ceramics or Teflon.

Therefore, although the main spindle 8 or the attachment main spindle and the tool holder 22 are electrically connected to each other, the tool TA or TB is insulated, and the tool TA or TB is insulated.
Even if the work W on the table 2 is cut with the ring sensor 1
No alternating current through the center of 6 is generated.

The coating of the electrically insulating material 25 such as ceramic is not limited to the shank portion of the tool TA or TB, and may be provided on the outer circumference and the rear end surface or the inner circumference of the straight collet 24 as shown in FIG. It has a similar insulating effect.

Further, as shown in FIG. 4, the tool holder main body 2
The same insulating effect can be obtained by coating the inner surface of the tapered collet 23a of No. 3 with an electric insulating material 25 such as ceramic. The taper collet 23a of the tool holder body 23,
There is no problem if the coating of the electrical insulating material 25 is provided on any of the straight collet 24 and the tools TA and TB, but any one of them is sufficient.

Next, the operation of this embodiment will be described.
Now, as shown in FIG. 7 (a), the extension attachment 14 is attached to the tip of the main spindle ram 7, and the ball having the attachment shank of the extension attachment 14 coated with the electrical insulating material 25 on the straight shank portion Ta via the tool holder 22. An end mill TA is attached and the bottom surface of the recess of the conductive work W is cut. In this state, the tool TA and the tool holder 22 are electrically insulated, so that no AC current flows through the spindle ram 7 and no AC voltage is induced in the ring sensor 16.

When the extension attachment 14 comes into contact with the wall surface of the work W during cutting, as shown in FIG. 7B, the AC power supply 17, the spindle head 6, the spindle ram 7, the extension attachment 14, the work W,
A closed circuit composed of the table 2 is formed, and a shunt current i supplied from the AC power supply 17 is also formed in the closed circuit.

Therefore, when an electric current flows through the central portion of the ring sensor 16, an AC current is induced in the iron core of the ring sensor 16, and an AC voltage is induced in the winding wound around the iron core. The induced AC voltage is sent to the AC amplification unit 18 and amplified, and an alarm signal is output from the alarm signal output unit 19, and the machine is stopped by the alarm via the alarm stop execution unit 21.

FIG. 7 (c) is a view showing a state in which the spindle ram 7 is in contact with the wall surface of the work W. Similar to FIG. 7 (b), an alternating voltage (signal) is induced in the ring sensor 16 to stop the alarm.

In FIG. 8 (a), a universal attachment 15 having the attachment spindle at right angles is attached to the spindle ram 7, and an electrical insulating material 25 is coated on the straight shank portion Ta via the tool holder 22 on the attachment spindle of the universal attachment 15. It shows a state in which the tool TA is attached and an oblique wall surface having an angle of the conductive work W is cut. In this state, the tool TA and the tool holder 22 are insulated from each other, so that no AC voltage (signal) is induced from the ring gauge 16.

When the main body portion 15a of the universal attachment 15 comes into contact with the bottom surface of the work W during the machining as shown in FIG. 8B, the shunt current i supplied from the AC power source 17 penetrates the spindle ram 7. Flow like
An AC voltage is induced in the winding of the ring gauge 16, an alarm stop signal is output via the amplification unit 18 and the alarm signal output unit 19, and an alarm stop is performed on the machine via the alarm stop execution unit 21.

FIG. 8C is a view showing a state in which the turning portion 15b of the universal attachment 15 is in contact with the convex portion on the bottom surface of the work W. In this case as well, the alarm is stopped as described above. It should be noted that the operation when the processing is performed using the angular attachment 13 is almost the same as the operation shown in FIG.

Second Embodiment In this embodiment, a conductive elastic body, a conductive protective cover such as a thin iron plate, etc. is provided on the main shaft ram 7, various attachments, and the tool holder 22 at positions where they easily interfere with the work W. The conductive elastic material is conductive rubber or resin, sponge, fiber (paper) mixed with a conductive material in the molding process.
An elastic material such as can be used. Since the other parts are the same as those in the first embodiment, the same parts are designated by the same reference numerals to avoid duplication, and the description thereof will be omitted.

FIG. 9 shows a holder body 2 of the tool holder 22 and a conductive protective cover 27 for covering the outer periphery of the lower end of the spindle ram 7.
3 is an example in which a conductive protective cover 28 is provided to cover the outer periphery of the lower end of No. FIG. 10 shows an example in which a conductive protective cover 29 that covers the lower end of the main body 15a of the universal attachment 15 is provided.

Further, FIG. 11 shows that the swivel portion 15 is provided outside the protective cover 29 of the main body portion 15a of the universal attachment 15.
This is an example in which a conductive protective cover 30 is also provided on b. Further, FIG. 12 shows an example in which a conductive protective cover 31 is provided at the lower end portion of the main body 14a of the extension attachment 14.

Since these protective covers 28 to 31 are attached to the site which easily interferes with the work W as described above, the cover has priority over the contact with the work W during cutting, whereby the center portion of the ring gauge 16 is contacted. When an alternating current flows through the ring gauge 16, an alternating voltage is induced in the ring gauge 16, the induced alternating voltage is amplified, an alarm signal is output, and the machine is stopped by an alarm.

Although the first and second embodiments have been described with respect to the collision preventing device in the portal type machining center, FIG.
It is of course applicable to a vertical machining center as shown in Fig. 3, and in this case, a ring sensor is provided on the tip surface of a ram type spindle head 33 which can be moved and positioned in the Z-axis direction so as to surround the main spindle 34 of the machine. 16 are provided. Needless to say, it can be applied to a horizontal machining center as well.

[0044]

Since the present invention is configured as described above, it has the following effects. According to a first aspect of the present invention, a detector is attached to a spindle head so as to surround a spindle ram or a spindle sleeve, and a shank portion is cut with an electric insulating material such as ceramic to perform cutting, and a machine including an attachment and a tool holder. When the area around the spindle of the machine contacts the work, a signal is output from the detector to stop the machine alarm. Therefore, it is possible to avoid a collision during machining of a machine tool such as a portal machining center while the damage is small.

According to the second aspect, the detector is attached to the ram type spindle head so as to surround the spindle of the machine, so that it can be applied to a machine tool such as a vertical machining center or a horizontal machining center, and the range of use is expanded. .

According to the third and fourth aspects of the present invention, the electrical insulating material is coated on the tool holding surface of the tool holder or on the inner surface or the outer peripheral surface of the straight collet. It is not necessary to coat the part with an electrically insulating material, and the tool cost can be reduced.

According to a fifth aspect of the present invention, the conductive protective cover provided at a portion around the spindle of the machine, including the spindle attachment and the tool holder, which is likely to interfere with the work, immediately stops the alarm when the work comes in contact with the work. Even if a slight trace of contact is left on the machine, there is no damage around the main axis of the machine, and a collision accident can be completely avoided.

[Brief description of drawings]

FIG. 1 is a block diagram of a control system and a block diagram of a portal machining center having a collision prevention device according to the present embodiment.

FIG. 2 is a front view of an angular attachment.

FIG. 3 is a front view of an extension attachment.

FIG. 4 is a front view showing the upper half of the tool holder in section.

FIG. 5 is a front view of a straight collet.

FIG. 6A is a front view of a flat end mill coated with an electric insulating material, and FIG. 6B is a front view of a ball end mill coated with an electric insulating material.

7A and 7B are operation explanatory views when the extension attachment of the first embodiment is used, in which FIG. 7A is a diagram illustrating a normal machining operation, FIG. 7B is a diagram illustrating a state in which the extension attachment and a workpiece collide, and FIG. 6] is a view showing a state where the spindle ram collides with the work.

8A and 8B are operation explanatory views when the universal attachment according to the first embodiment is used, FIG. 8A is a diagram illustrating a normal processing, and FIG. 8B is a diagram illustrating a state where the main body portion of the universal attachment collides with the work. , (C) are diagrams showing a state in which the rotating portion of the universal attachment collides with the work.

FIG. 9 is a diagram in which a protective cover according to a second embodiment is provided on a spindle ram and a tool holder.

FIG. 10 is a diagram in which the protective cover of the second embodiment is provided on the main body of the universal attachment.

FIG. 11 is a view in which the protective cover according to the second embodiment is provided on the main body and the turning portion of the universal attachment.

FIG. 12 is a diagram in which a protection cover according to a second embodiment is provided on an extension attachment.

FIG. 13 is a perspective view of a vertical machining center having a collision prevention device according to another embodiment.

FIG. 14 is a diagram showing a state immediately before a collision between a work of the related art and a spindle ram or a spindle sleeve.

FIG. 15 is a diagram showing a state immediately before a collision between a workpiece and a tool holder according to a conventional technique.

FIG. 16 is a diagram of a collision prevention device according to a reflected sound of ejected air according to a conventional technique.

FIG. 17 is a view of a prior art attachment and a workpiece interference prevention device.

FIG. 18 is a diagram of a prior art arbor collision avoidance device.

FIG. 19 is a view of a conventional ultrasonic collision prevention device.

FIG. 20 is a diagram of a collision prevention device having a prior art ram with an object sensing device.

[Explanation of symbols]

1 bed 2 table 6
Spindle head 7 Spindle ram 8,34 Machine spindle 13 Angular attachment 14 Extension attachment 15 Universal attachment 16 Ring sensor 17 AC power supply 18 Amplifier 19 Alarm signal output 21 Alarm stop execution 22 Tool holder 24 Straight collet 25 Electrical insulation 33 Ram type spindle head TA Ball end mill TB Flat end mill W work

Claims (5)

[Claims] 1. A device for preventing a collision between a spindle of a machine including an attachment and a tool holder and a work including an electrically conductive setup during machining, wherein the spindle head surrounds a spindle ram or a spindle sleeve. A detector that is provided and obtains a signal by an alternating current that penetrates the center of the machine when the work is in contact with the main shaft of the machine, a member that stops the machine alarm by the output signal of the detector, and a weak AC for the machine. Collision preventive device comprising a power supply for supplying an electric current and an electric insulating material provided on the surface of the shank portion of a cutting tool attached to the main spindle of the machine or the attachment main spindle via a tool holder to insulate the tool holder from the cutting tool . 2. The collision prevention device according to claim 1, wherein the detector is provided on a ram type spindle head so as to surround the main spindle of the machine. 3. The collision prevention device according to claim 1, wherein an electric insulating material is provided on a tool holding surface of the tool holder. 4. The collision prevention device according to claim 1, wherein the electrical insulating material is provided on the inner surface or the outer surface of the straight collet. 5. A conductive protective cover is provided on a portion of a machine including a spindle attachment and a tool holder, which is likely to interfere with a work around the spindle of a machine.
The collision prevention device according to the paragraph.