JP4727602B2 - Tool lock device and tool lock method for machine tool - Google Patents

Description

  The present invention relates to a tool lock device and a tool lock method for a machine tool that clamps or unclamps a tool disposed at a tip end of a spindle of a machine tool.

  Generally, a machine tool is provided with a tool lock device that clamps or unclamps a tool on a main shaft. In the tool lock device, a rod having a clamp mechanism is passed through the main shaft, and the tool is clamped or unclamped by pushing and pulling the rod.

  That is, by pulling the rod, the shank portion of the tool is clamped by the clamp mechanism of the rod, the taper portion of the tool is fitted into a tapered hole formed at the tip portion of the main shaft, and the tool is mounted on the main shaft. . On the other hand, by pushing the rod, the shank portion of the tool is unclamped by the clamp mechanism of the rod, the tapered portion of the tool is separated from the tapered hole of the main shaft, and the tool is detached from the main shaft.

  Such a conventional tool lock device of a machine tool is disclosed in, for example, Patent Document 1.

JP-A-11-90708

  In the conventional tool lock device described above, a ball is used for the clamp mechanism, so that a high clamping force is generated and the tool is mounted on the spindle. However, when the tool is clamped with such a high clamping force, the taper portion of the tool is fixed to the taper hole of the main shaft, and the tool may not be removed from the main shaft during unclamping.

  Further, since the tapered hole of the main shaft has a shape in which the tip opening is expanded, when the main shaft is cut at high speed, the diameter tends to increase toward the tip. As a result, when a cutting reaction force is applied to the tool, the tapered portion tends to enter the proximal end opening side of the tapered hole of the main shaft, and the tapered portion of the tool is fixed to the tapered hole of the main shaft. .

  Thus, when the tool cannot be removed from the main spindle, for example, in a machine tool such as a machining machine that performs processing while automatically exchanging various tools with the main spindle, the work efficiency is lowered and the productivity is lowered. May be incurred.

  Accordingly, the present invention solves the above-described problems, and provides a tool lock device and a tool lock method for a machine tool that can eliminate the sticking between the tool and the spindle and can easily remove the tool from the spindle. Objective.

A tool lock device for a machine tool according to a first invention for solving the above-described problems,
A spindle that is rotatably supported and holds the tool detachably on the inner peripheral surface of the tip,
A rod that is slidably supported coaxially with the main shaft in the hollow portion of the main shaft, and that can contact the tool attached to the inner peripheral surface of the tip end portion of the main shaft ;
A clamping mechanism is supported by the rod, clamp or unclamp the tool attached to the distal end inner peripheral surface of the spindle,
An urging means for urging the clamp mechanism by urging the rod toward the main shaft proximal side;
A pressing means that puts the clamp mechanism into an unclamped state by pressing the rod against the urging force of the urging means toward the front end of the main shaft;
A vibration element provided in the circumferential direction of the inner peripheral surface of the tip of the main shaft;
And a control unit that vibrates the vibration element until the clamp mechanism unclamps the tool fully open after the rod slides toward the front end of the spindle and comes into contact with the tool .

A tool lock device for a machine tool according to a second invention for solving the above-described problems,
In the tool lock device of the machine tool according to the first invention,
Displacement amount detection means for detecting the displacement amount of the rod displaced by the pressing means,
When the pressing force of the pressing means is generated and the displacement amount of the rod detected by the displacement amount detecting means does not reach the predetermined amount by a predetermined time, the control means presses the pressing force of the pressing means. It is characterized by controlling so as to increase.

A tool lock method for a machine tool according to a third invention for solving the above-mentioned problem is as follows.
A tool locking method for a machine tool that clamps or unclamps a tool removably mounted on the inner peripheral surface of a tip end of a spindle by pushing and pulling a rod inserted into the spindle,
Clamping the tool by urging the rod toward its proximal end, while unclamping the tool by pressing the rod toward its distal end,
The inner peripheral surface of the tip end portion of the spindle is vibrated until the tool is fully unclamped after the rod is pressed toward the tip end and abutted against the tool .

  According to the tool lock device and the tool lock method for a machine tool according to the present invention, the vibration between the main shaft and the tool can be eliminated by vibrating the vibration element provided on the main shaft, so that the tool can be easily removed from the main shaft. Can be extracted.

  Hereinafter, a tool lock device and a tool lock method for a machine tool according to the present invention will be described in detail with reference to the drawings. 1 is a cross-sectional view of a tool lock device for a machine tool according to the present invention, FIG. 2 is a time chart showing the relationship between the amount of displacement of a rod and the pressing force of a piston when tool removal is normal, and FIG. FIG. 4 is a diagram showing the relationship between the frequency and the amplitude of the piezo element member.

  In FIG. 1, the upper side of the axis of the spindle shows the clamped state of the tool, and the lower side shows the unclamped state of the tool. In FIGS. 2 and 3, the solid line indicates the amount of displacement of the rod, and the alternate long and short dash line and the dotted line indicate the pressing force of the piston.

  As shown in FIG. 1, a cylindrical housing 12 is provided in a machine tool such as a machining center (not shown). A cylindrical main shaft 14 is rotatably supported in the housing 12 via bearings 13a, 13b, and 13c, and a tool 11 is mounted on the tip of the main shaft 14.

  The main shaft 14 has a tapered hole 14a that expands in a conical shape in the distal direction at the distal end portion, and a hollow portion 14b that communicates with the proximal end portion of the tapered hole 14a and extends in the axial direction of the main shaft 14. ing. Four piezo element members (vibrating elements) 17 made of piezo elements are embedded in the main shaft 14 at a substantially intermediate portion in the axial direction of the tapered hole 14a. The piezo element members 17 are arranged at substantially equal intervals in the circumferential direction of the main shaft 14 (taper hole 14a) and so as to face the inclined surface of the taper hole 14a.

  A tapered portion 11a formed in a conical shape on the proximal end side of the tool 11 is mounted in the tapered hole 14a of the main shaft 14, while a cylindrical rod 18 slides in the axial direction of the hollow portion 14b. Inserted as possible. A collet (clamp mechanism) 19 is rotatably provided at the tip of the rod 18. By rotating the collet 19, the collet 19 is attached to the proximal end portion of the taper portion 11 a of the tool 11. It is possible to engage with the formed shank portion 11b.

A disc spring (biasing means) 21 is disposed outside the rod 18. An annular guide member 23 and a sleeve 24 are adjacently fixed to the inner peripheral surface of the distal end of the hollow portion 14 b of the main shaft 14, and a sleeve 25 is fixed to the outer peripheral surface of the base end portion of the rod 18. Yes. The disc spring 21 has a distal end connected to the sleeve 24 and a proximal end connected to the sleeve 25.

  Accordingly, the distal end portion of the rod 18 and the collet 19 are inserted into the guide member 23 and are slidably guided. The disc spring 21 is disposed in a compressed state between the sleeves 24 and 25, and the urging force of the disc spring 21 urges the rod 18 toward the proximal end in the axial direction within the main shaft 14. .

  A cylinder 26 supported by the housing 12 is provided on the proximal end side of the main shaft 14. A cylindrical piston 27 is slidably supported in the cylinder 26, and the distal end portion of the piston 27 can come into contact with the base end portions of the rod 18 and the sleeve 25 by the sliding. In the cylinder 26, two hydraulic chambers 26a and 26b separated in the axial direction by the piston 27 are formed. The hydraulic chambers 26a and 26b are connected to a hydraulic source 28, and by operating the hydraulic source 28, hydraulic pressure is supplied to and discharged from the hydraulic chambers 26a and 26b. Note that the cylinder 26, the piston 27, and the like constitute pressing means.

  That is, when the hydraulic pressure is supplied to the hydraulic chamber 26 a of the cylinder 26, the piston 27 is retracted from the base end portion of the rod 18 and the sleeve 25, so that the rod 18 is also retracted by the biasing force of the disc spring 21. Thereby, the collet 19 is closed and the shank portion 11b of the tool 11 is clamped (clamped state). On the other hand, when the hydraulic pressure is supplied to the hydraulic chamber 26 b of the cylinder 26, the piston 27 moves forward and comes into contact with the base end portion of the rod 18 and the sleeve 25. Advance. Thereby, the collet 19 opens and the shank part 11b of the tool 11 is unclamped (unclamped state).

  Here, the piezo element member 17 is connected to the power source 30, and when an electric current is supplied from the power source 30, an amplitude (microvibration) of 2 to 3 μm is generated at a frequency of 10 KHz or more. Specifically, as shown in FIG. 4, when a current is supplied, the frequency changes from 10 KHz to 30 KHz, and when the frequency reaches 20 KHz, the maximum amplitude is 3 μm. That is, the frequency domain is set between before and after the maximum amplitude of 20 KHz. In order to supply current from the power supply 30 to the piezo element member 17, lead wires are wired in the main shaft 14 to energize.

  Further, a displacement sensor (displacement amount detecting means) 31 is provided on the inner peripheral surface of the housing 12, and a ring-shaped ring member 32 is provided at the proximal end portion of the sleeve 25. And the displacement amount to the axial direction of the rod 18 is detected by measuring the gap between the ring members 32 by the displacement sensor 31.

  The machine tool is provided with an NC device (control means) 33 for controlling the entire machine tool. The NC device 33 includes a timer for measuring time therein, and is connected to the hydraulic power source 28, the power source 30, the displacement sensor 31, and the like, and inputs signals to the hydraulic power source 28 and the power source 30, while the displacement sensor The signal from 31 is input. That is, the NC device 31 controls the supply of current to the piezo element 17, supply / discharge of hydraulic pressure to the hydraulic chambers 26 a and 26 b of the cylinder 26, and detection of the displacement amount of the rod 18.

  Next, the tool change operation by the NC device 33 will be described with reference to FIGS.

  When a workpiece (not shown) is machined by the machine tool, hydraulic pressure is supplied to the hydraulic chamber 26a of the cylinder 26. As a result, the piston 27 is retracted from the base end portion of the rod 18 and the sleeve 25, and the rod 18 is also retracted by the biasing force of the disc spring 21. As a result, the collet 19 is closed and the shank portion 11b of the tool 11 is clamped, and the taper portion 11a of the tool 11 is drawn into the taper hole 14a of the main shaft 14 and fitted.

  As shown in FIG. 2, when the machining of the workpiece is completed, the spindle 14 moves to the tool change position (0 seconds). In such a clamping state (upper clamping state in FIG. 1), as described above, since the hydraulic pressure is supplied to the hydraulic chamber 26a of the cylinder 26, the piston 27 moves backward and the pressing force to the rod 18 is Thus, the amount of forward displacement of the rod 18 is also 0 mm.

  When 1.0 second has elapsed, the tool detachment operation is started. That is, a predetermined amount of hydraulic pressure is supplied to the hydraulic chamber 26b of the cylinder 26, and the piston 27 is gradually advanced. Finally, in 1.3 seconds, the pressing force of the piston 27 is 1.5t, and the rod 18 is advanced. The amount of displacement is 5 mm. As a result, the tip of the rod 18 contacts the end face of the shank portion 11b of the tool 11, and the collet 19 opens to unclamp the shank portion 11b (lower unclamped state in FIG. 1).

  Next, when 1.9 seconds have elapsed, a predetermined amount of hydraulic pressure is further supplied to the hydraulic chamber 26b of the cylinder 26, the piston 27 is gradually advanced, and finally the pressure of the piston 27 is reduced to 2 at 2.0 seconds. In this state, the rod 18 is pushed up to 4.0 seconds to advance the rod 18 to a displacement of 7 mm. Thus, when the rod 18 moves forward by 2 mm between 1.9 and 2.0 seconds, the tip of the rod 18 presses the end surface of the shank portion 11b of the tool, and the taper portion 11a of the tool 11 is pressed. Is separated from the tapered hole 14 a of the main shaft 14. That is, the tool 11 is detached from the main shaft 14.

  Here, the collet 19 unclamps the shank portion 11b of the tool 11 in the unclamp preparation state until the collet 19 is fully unclamped (at the time of rotation) between 1.0 and 2.0 seconds described above. However, the taper part 11a of the tool 11 may be fixed to the taper 14a of the main shaft 14 in some cases. In such a case, there is a possibility that the tool 11 will not be detached even if the pressure is applied to the piston 27 to 2.0 t and the tool 11 is pressed by the rod 18 in such a case.

  Therefore, in the tool lock device for a machine tool according to the present invention, the piezo element member 17 is moved between 1.3 and 2.0 seconds (fine vibration generation period) in the unclamp ready state, that is, before the maximum pressing force is generated. Slightly vibrates. That is, in 1.3 seconds, the piston 27 generated a pressing force of 1.5 t, and the rod 18 moved forward by 5 mm and contacted the tool 11 (at this time, no pressing force was applied to the tool 11). At the same time, the micro-vibration of the piezo element member 17 is started, and in 2.0 seconds, the piston 27 generates a pressing force of 2.0 t, and the rod 18 further advances 2 mm to press the tool 11. Simultaneously with the detection, the fine vibration of the piezo element member 17 is stopped. As a result, the taper portion 11a of the tool 11 and the taper hole 14a of the main shaft 14 are eliminated, and the tool 11 can be easily detached from the main shaft 14.

  In addition, between 2.0 and 4.0 seconds, the tool 11 that is detached from the spindle 14 and the tool 11 that performs the next machining are exchanged, and the taper portion 11a of the tool 11 that performs the next machining. Is in a state of being fitted into the tapered hole 14a of the main shaft 14 (an unclamped state on the lower side of FIG. 1).

  When 4.0 seconds have elapsed, the tool mounting operation of the tool 11 for performing the next machining is started. That is, a predetermined amount of hydraulic pressure is supplied to the hydraulic chamber 26a of the cylinder 26, and the piston 27 is gradually retracted. Finally, in 4.3 seconds, the pressing force of the piston 27 is set to 0t, and the biasing force of the disc spring 21 is used. The rod 18 is retracted and its displacement is set to 0 mm. Therefore, the tip of the rod 18 is retracted from the end face of the shank portion 11b of the tool 11 in the clamp preparation state until the collet 19 is fully closed (turned) between 4.0 and 4.3 seconds. At the same time, the collet 19 is closed to clamp the shank portion 11b (upper clamped state in FIG. 1). That is, the tool 11 is mounted on the main shaft 14.

  Here, if the tool 11 is fixed and does not detach from the main shaft 14 even if the pressing force of the piston 27 is 2.0 t in 2.0 to 4.0 seconds, as shown in FIG. Between 2.0 seconds and a lapse of a predetermined time (for example, t = 3.0), it is determined from the displacement amount of the rod 18 whether or not the tool 11 is detached, and the displacement amount of the rod 18 reaches 7 mm. If it is determined that it is not, a predetermined amount of hydraulic pressure is supplied to the hydraulic chamber 26b of the cylinder 26 immediately after the determination, and the pressing force of the piston 27 is increased from 2.0t to 3.0t. You may do it.

  Also, instead of generating the pressing force of the piston 27 constant at 3.0 t, as shown by the dotted line in FIG. 3, the hydraulic pressure is increased so that the pressing force is gradually increased until the displacement amount of the rod 18 reaches 7 mm. It is also possible to supply.

  By adjusting the pressing force of the piston 27 in this way, even when an abnormality occurs in the extraction of the tool 11 as shown in FIG. 3, the tool 11 as shown in FIG. The time (4.0 seconds) for starting the tool mounting operation of the tool 11 for performing the next machining does not change.

  It should be noted that the micro-vibration of the piezo element member 17 is started at the same time when the hydraulic pressure is supplied to the hydraulic chamber 26b of the cylinder 26, that is, when the operation of the cylinder 26 toward the front end of the main shaft is performed (at the time of 1 second) The fine vibration of the piezo element member may be stopped at the same time when the displacement amount of the rod 18 reaches 7 mm.

Therefore, according to the tool lock device for a machine tool according to the present invention, the tool 11 is pressed through the rod 18 by the pressing force of the piston 27, and a current is supplied to the piezo element member 17 when the piston 27 is operated. By vibrating, the taper portion 11a of the tool 11 and the taper hole 14a of the main shaft 14 can be eliminated, so that the tool 11 can be easily removed from the main shaft 14. Further, by using the compact piezo element member 17 as the vibration element, it can be provided in the main shaft 14 and the enlargement of the entire apparatus can be prevented.

  Further, when the pressing force of the piston 27 is generated and the displacement amount of the rod 18 does not reach the predetermined amount by a predetermined time, the pressing force of the piston 27 is increased, so that the tool 11 is surely secured. In addition, the pressure can be removed more than necessary, so that it is possible to save labor. Further, even if such an abnormal situation occurs that the tool 11 is fixed and the rod 18 is not displaced, the tool extraction time can be made the same as that at the normal time, so that the work start time of the next machining is prevented from being delayed. can do.

  The present invention can be applied to a tool lock device of a machine tool that can detect whether or not a tool is correctly mounted on a spindle.

It is sectional drawing of the tool lock apparatus of the machine tool which concerns on this invention. It is the time chart which showed the relationship between the displacement amount of the rod at the time of tool extraction normal, and the pressing force of a piston. It is the time chart which showed the relationship between the displacement amount of a rod at the time of tool extraction abnormality, and the pressing force of a piston. It is the figure which showed the relationship between the frequency and amplitude in a piezo element member.

Explanation of symbols

11 Tool 11a Tapered part 11b Shank part 12 Housing 13a-13c Bearing 14 Main shaft 14a Tapered hole 14b Hollow part 17 Piezo element member 18 Rod 19 Collet 21 Belleville spring 23 Guide member 24, 25 Sleeve 26 Cylinder 26a, 26b Hydraulic chamber 27 Piston 28 Hydraulic source 30 Power source 31 Displacement sensor 32 Ring member 33 NC device

Claims (3)

A spindle that is rotatably supported and holds the tool detachably on the inner peripheral surface of the tip,
A rod that is slidably supported coaxially with the main shaft in the hollow portion of the main shaft, and that can contact the tool attached to the inner peripheral surface of the tip end portion of the main shaft ;
A clamping mechanism is supported by the rod, clamp or unclamp the tool attached to the distal end inner peripheral surface of the spindle,
An urging means for urging the clamp mechanism by urging the rod toward the main shaft proximal side;
A pressing means that puts the clamp mechanism into an unclamped state by pressing the rod against the urging force of the urging means toward the front end of the main shaft;
A vibration element provided in the circumferential direction of the inner peripheral surface of the tip of the main shaft;
And a control unit that vibrates the vibration element until the clamp mechanism unclamps the tool fully open after the rod slides toward the front end of the spindle and comes into contact with the tool. Machine tool lock device. The tool lock device for a machine tool according to claim 1,
Displacement amount detection means for detecting the displacement amount of the rod displaced by the pressing means,
When the pressing force of the pressing means is generated and the displacement amount of the rod detected by the displacement amount detecting means does not reach the predetermined amount by a predetermined time, the control means presses the pressing force of the pressing means. A tool lock device for a machine tool, characterized in that control is performed to increase the tool size. A tool locking method for a machine tool that clamps or unclamps a tool removably mounted on the inner peripheral surface of a tip end of a spindle by pushing and pulling a rod inserted into the spindle,
Clamping the tool by urging the rod toward its proximal end, while unclamping the tool by pressing the rod toward its distal end,
An inner peripheral surface of the tip end portion of the spindle is vibrated until the tool is fully unclamped after the rod is pressed toward the tip end and abutted on the tool . Tool lock method.

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