JP6810918B2 - Tool unclamping device for machine tools and tool unclamping method - Google Patents

Description

The present invention relates to a machine tool tool unclamping device and an unclamping method that enable a reduction in tool changing time in a machine tool automatic tool changing device (ATC).

In an automatic tool changer for a machine tool, tool change is performed by a spindle unit having a spindle for holding a tool and a changer unit for changing tools. As such an automatic tool changing device, for example, those described in Patent Documents 1 and 2 are known.
The automatic tool changer described in Patent Document 1 relates to a method of adjusting the timing between a swivel arm for changing a tool and an operation of a drawbar for clamping or unclamping the tool by sliding in the axial direction inside the spindle. Is.

Further, the drawbar position detection mechanism described in Patent Document 2 detects the movement of the drawbar movement detection portion that moves with respect to the pressing member that presses the drawbar in the unclamping direction due to the movement of the drawbar in the clamping direction and the unclamping direction. A displacement sensor is provided. By detecting the position of the drawbar with a displacement sensor, it is possible to confirm that the tool is correctly clamped to the spindle.

Japanese Patent No. 5621368 Japanese Patent No. 423017

However, in the tool unclamping device in the automatic tool changing device of a machine tool as described in Patent Documents 1 and 2, the unclamping and clamping of the tool are performed by the operation of the hydraulic piston in the spindle. In particular, in order to unclamp the drawbar in the tool clamp state, a large thrust is required for the hydraulic piston to compress the clamp spring such as the disc spring that urges the drawbar in the tool clamp direction, and the support for tool replacement. It took a long time to later switch the drawbar to the unclamped position. Therefore, there is a drawback that the time required for tool replacement becomes long.

In addition, with the taper shank of the tool attached to the tapered hole at the tip of the spindle, the lubrication of the tapered hole between the tool and the spindle is insufficient, or the spindle is heated at high speed for cutting, or centrifugal force. If a large cutting force is applied while the tapered hole of the spindle is inflated, the tool will bite into the tapered hole of the spindle when the tool is pushed into the tapered hole of the spindle. After that, when the rotation of the spindle is stopped and the temperature drops, the tool will further bite into the spindle.
If the tool is replaced from such a state where the tool is biting, it may be difficult to remove the tool. Therefore, also in this respect, there is a problem that it takes a long time to replace the tool from the state where the tool bites into the tapered hole.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a tool unclamping device and an unclamping method for a machine tool in which the time required for unclamping a tool in tool change is shortened. And.
Another object of the present invention is to provide a tool unclamping device and an unclamping method for a machine tool, which reduces the bite of the tool on the spindle so that the tool can be easily pulled out.

The tool unclamping device for a machine tool according to the present invention has a hollow spindle to which a tool is attached to the tip, and a clamp of the tool that is movably arranged in the spindle in the direction of the central axis. A tool gripping member that selectively unclamps, an urging member that urges the tool gripping member in the tool clamping direction, an unclamping operating member that moves the tool gripping member in the unclamping direction, and an unclamping operation. In a machine tool unclamping device provided on a member and provided with a hydraulic chamber that presses the tool gripping member in the unclamping direction by supplying hydraulic pressure, a low-pressure oil is supplied to the hydraulic chamber by an unclamping operating member. A low-pressure oil supply circuit that presses the tool gripping member and the urging member in the unclamping direction, and a tool gripping member that supplies high-pressure oil higher than the low-pressure oil to the hydraulic chamber and opposes the urging member by the unclamping operating member. It is equipped with a high-pressure oil supply circuit that unclamps the tool by pushing and a switching member that switches between low-pressure oil and high-pressure oil and supplies it to the hydraulic chamber, and supplies low-pressure oil to the hydraulic chamber before tool replacement. The tool gripping member is pressed at a low pressure via the unclamping actuating member to prepare the urging member for compression, and high pressure oil is supplied to the hydraulic chamber at the tool change stage to supply the tool gripping member via the unclamping actuating member. It is characterized in that the tool is unclamped by pushing in.
When replacing the tool mounted on the tool holding part of the spindle, low pressure oil is supplied to the hydraulic chamber to operate the unclamping actuating member to press the tool gripping member at low pressure and the urging member before the tool replacement. In the next tool change stage, high pressure oil is supplied to the hydraulic chamber instead of low pressure oil to operate the unclamping actuating member with a larger load, and the tool is already urged in the tool change stage. Since the preparation for compression of the member is completed, the tool gripping member can be quickly pushed in to bring the tool into an unclamped state in which the tool can be pulled out from the spindle.

In addition, a spindle air blow flow path that is provided on the spindle and supplies air containing air or lubricating oil to the space behind the tool holding portion of the spindle is provided, and air is passed through the spindle air blow flow path before tool replacement. It is preferable to fill the space portion with.
Since the space is filled with air before the tool is changed, even if the tool is pulled out at high speed during the tool change, the air can be immediately ejected to the tool or the tool holding part of the spindle. , It is possible to prevent the adhesion of dust and the like. Moreover, by mixing the mist-like lubricating oil with the air, the tool and the tool holding portion of the spindle can be quickly lubricated, and the biting of the tool can be suppressed.

In addition, an auxiliary air blow flow path provided in the unclamping actuating member and connectable to the spindle air blow flow path is further provided, and the unclamping actuating member is pushed to open the auxiliary air blow flow path before changing the tool. It may be connected to the spindle air blow flow path to fill the space with air.
By bringing the unclamping actuating member provided with the auxiliary air blow flow path into contact with the tool gripping member provided with the spindle air blow flow path, air can be sent from the auxiliary air blow flow path to the space portion.

Further, a changer arm for gripping the tool attached to the spindle for automatic replacement is provided, and the impact of gripping the tool with the changer arm may release the bite of the spindle with respect to the tool.
Even if the tool bites into the tool holding portion of the spindle, the bite can be released by the impact when the changer arm grips the tool at the time of tool replacement.

In the tool unclamping method of a machine tool according to the present invention, a hollow spindle to which a tool is attached to the tip and a tool clamp and unclamping are arranged in the spindle so as to be movable in the axial direction by moving in the central axis direction. It is provided in the tool gripping member to be selectively performed, the urging member for urging the tool gripping member in the clamping direction, the unclamping operating member for moving the tool gripping member in the unclamping direction, and the unclamping operating member. In the tool unclamping method of a machine tool equipped with a hydraulic chamber that presses the tool gripping member in the unclamping direction by supplying hydraulic pressure, the unclamping operation is performed by supplying low pressure oil to the hydraulic chamber before the tool change. The preparatory operation of pressing the tool gripping member at a low pressure via the member to compress the urging member is completed, and the low pressure oil supplied to the hydraulic chamber at the tool change stage is switched to the high pressure oil via the unclamping actuating member. It is characterized in that the tool gripping member is pushed in to unclamp the tool.
According to the tool unclamping method of a machine tool according to the present invention, when a tool mounted on a tool holding portion of a spindle is replaced, low pressure oil is supplied to a hydraulic chamber to operate an unclamping operating member before the tool replacement. The tool gripping member is pressed at a low pressure to complete the preparation for compression of the urging member, and at the next tool change stage, high pressure oil is supplied to the hydraulic chamber instead of the low pressure oil to further increase the unclamping operating member. When operated with a large load, the preparatory operation for compressing the urging member has already been completed, so the tool gripping member can be quickly pushed in and the tool can be pulled out from the spindle in an unclamped state. You can do it faster.

Before changing the tool, low-pressure oil is supplied to the hydraulic chamber to press the unclamping operating member against the tool gripping member at low pressure, and air or air mixed with lubricating oil is applied to the space behind the tool holding part on the spindle. The air in the space portion may be blown out to the tool and the tool holding portion by pulling out the tool from the spindle by the changer arm in the step of supplying and filling the portion and the tool changing stage.
Since air can be quickly ejected from the space when the tool is pulled out, the lubricating oil and the like can be reliably attached to the tool and the tool holding portion and dust and the like can be surely removed, and the tool can be replaced more quickly.

In addition, after gripping the tool mounted on the spindle with the changer arm, the low-pressure oil supplied to the hydraulic chamber is switched to high-pressure oil, and the tool gripping member is pushed in via the unclamping operating member to unclamp the tool. It may be.
At the time of tool change, the bite of the tool can be released by the impact when the tool is gripped by the changer arm, and the tool gripping member can be pushed in with high pressure oil to quickly unclamp the tool.

According to the tool unclamping device and the unclamping method of the machine tool according to the present invention, the tool gripping member that holds the tool by the unclamping operating member at a low pressure is pressed in the unclamping direction at a low pressure before the tool change. The preparation for compression of the force member is completed, and in the next tool change stage, the tool gripping member is pushed in the unclamping direction via the unclamping actuating member with high-pressure oil to unclamp the tool in a short time. It can be done smoothly.

It is sectional drawing which shows the main part structure of the tool unclamping apparatus in the spindle unit of the automatic tool changing apparatus by embodiment of this invention. It is an enlarged sectional view of the push rod and the collet of the spindle unit shown in FIG. FIG. 3 is a partial cross-sectional view showing a spindle air blow flow path and an auxiliary air blow flow path in the spindle unit shown in FIG. FIG. 5 is an enlarged cross-sectional view of an unclamping piston provided in the hydraulic chamber of the tool unclamping device shown in FIG. It is explanatory drawing of the main part which shows the tool change position by the changer arm in an automatic tool change device. It is a hydraulic circuit diagram which shows the low pressure oil supply circuit and high pressure oil supply circuit in a tool unclamping device. It is a flowchart of the normal mode which shows the tool unclamping method in embodiment. It is a flowchart by the modification which shows the tool unclamping method which took the tool bite prevention measures.

Hereinafter, the tool unclamping device in the automatic tool changing device of the machine tool according to the embodiment of the present invention will be described with reference to FIGS. 1 to 7.
1 to 4 show a tool unclamping device 3 provided on the spindle unit 2 of the automatic tool changing device 1 according to the embodiment. In the spindle unit 2 shown in FIG. 1, a substantially tubular housing body 5 fixed to a spindle head (not shown) such as a machining center, a hollow spindle 6 rotatably provided around a bearing inside the housing body 5, and a hollow spindle 6 provided therein. An unclamping mechanism 7 is provided at the rear of the spindle 6 so as to be able to move forward and backward. In the present specification, the tool 13 side of the spindle unit 2 in FIG. 1 is referred to as the front side and the front side, and the unclamp mechanism 7 side is referred to as the rear side and the rear side.
The front portion of the spindle 6 is held by the housing body 5 via the front bearing 9, and the rear portion is held by the housing body 5 via the rear bearing 10. Inside the housing body 5, a motor rotor 11 is installed inside as an electric motor M1 for rotating the spindle 6 around the central axis O between the front bearing 9 and the rear bearing 10, and a motor stator 12 is installed outside the motor rotor 11. is set up.

A taper hole 6a into which the taper shank 13a of the tool 13 is fitted is formed as a tool holding portion at the front end portion of the spindle 6, and a pull stud 13b is provided at the rear end portion of the taper shank 13a of the tool 13. A V-flange 13c for gripping with a changer arm 53, which will be described later, is formed on the outer peripheral surface of the tool 13 on the distal end side following the taper shank 13a.
A substantially tubular hole 6b that communicates with the tapered hole 6a of the main shaft 6 and extends in the central axis O direction is formed, and a pull stud 13b can be gripped on the front side of the hole 6b in the front-rear direction of the central axis O. A movable collet 15 is installed. A push rod 16 is connected to the rear portion of the collet 15, and the rear end portion of the push rod 16 projects from the rear end of the spindle 6. Therefore, the collet 15 moves back and forth due to the back and forth movement of the push rod 16. A claw portion 15a for gripping the pull stud 13b of the tool 13 is formed at the tip end portion of the collet 15.

At the tip of the hole portion 6b of the main shaft 6, a space portion 18 having an enlarged diameter is formed in a portion communicating with the tapered hole 6a. When the collet 15 moves forward in the hole 6b, the claw portion 15a enters the space 18 and expands in diameter to rotate to release the pull stud 13b, and when the collet 15 moves backward. The claw portion 15a is housed in the hole portion 6b, the diameter is reduced, and the pull stud 13b is gripped.
In FIG. 2, a diameter-expanded hole portion 6d is formed in the central axis O direction of the hole portion 6b of the main shaft 6 via the front side step portion 6c, and the push rod 16 has a front spring retainer that can be locked to the front side step portion 6c. A rear spring retainer 22 provided behind the 21 and fixed to the push rod 16 is installed at a predetermined interval. The front spring retainer 21 and the rear spring retainer 22 are installed in the enlarged hole portion 6d. An urging member 23 made of, for example, a disc spring is attached between the front spring retainer 21 and the rear spring retainer 22 in a compressed state.

Therefore, the push rod 16 is urged rearward (in the clamp direction) via the rear spring retainer 22 by the urging force of the urging member 23 and is pulled into the hole 6b, whereby the collet 15 is pulled backward and the tool 13 Clamp the pull stud 13b. The urging member 23 pushes the rear spring retainer 22 together with the push rod 16 in the enlarged hole portion 6d. Further, when the push rod 16 is pushed forward (in the unclamping direction) by the unclamping piston 28 described later, the rear spring retainer 22 is engaged with the front spring retainer 21 locked by the front side step portion 6c. Compress.
In FIG. 3, in the enlarged hole portion 6d of the hole portion 6b, from the rear end portion of the spindle 6, the hole passage of the push rod 16, the hole passage of the rear spring retainer 22, the urging member 23, and the hole of the front spring retainer 21. A tubular spindle air blow passage 25 extending to the space 18 through the passage is formed. Through the spindle air blow flow path 25, the air flowing from the airport 41, which will be described later, is blown into the space portion 18.

Further, as shown in FIG. 4, a substantially cylindrical hydraulic chamber 27 is formed around the central axis O in the cylinder 26 of the unclamping mechanism 7 behind the main shaft 6. Diameter-expanded grooves 27a and 27b whose diameters are expanded in the front-rear direction are formed on the outer peripheral side of the hydraulic chamber 27, and the diameter-reduced portion 27c whose central axis O-side surface is smaller than the diameter-expanded grooves 27a and 27b. Form. The push rod 16 has a step portion 16a at the rear end portion of the main shaft 6, and the shaft portion 16b behind the step portion 16a penetrates the inside of the hydraulic chamber 27 and projects outward from the rear of the housing body 5.
An unclamping piston 28 is installed in the hydraulic chamber 27 so as to be able to advance and retreat along the shaft portion 16b of the push rod 16, and the main body portion 28a of the unclamping piston 28 has a substantially cylindrical shape coaxial with the hydraulic chamber 27. Is formed in. The rear end portion of the unclamping piston 28 projects outward from the rear end surface of the housing body 5, and the nut 31 is screwed into the rear end portion. When the unclamping piston 28 moves forward, the nut 31 comes into contact with the rear end surface of the housing body 5 to stop, and regulates the sliding range of the unclamping piston 28 in the unclamping direction.

On the outer peripheral surface of the unclamping piston 28, a substantially disk-shaped operating wing 28b whose diameter is increased from the main body portion 28a toward the inner peripheral surface in the hydraulic chamber 27 is formed. A sealing member 29 that seals between the inner peripheral surface of the hydraulic chamber 27 and the inner peripheral surface of the hydraulic chamber 27 is embedded in the outer peripheral surface of the operating blade 28b that slidably contacts the inner peripheral surface of the hydraulic chamber 27 over the entire circumference.
Further, a clamp hydraulic port 33 is formed in communication with the outer diameter surface of the housing body 5 from the outer peripheral surface of the housing body 5 in the enlarged diameter groove 27a on the front side of the hydraulic chamber 27, and high-pressure oil is supplied. When high-pressure oil is supplied into the hydraulic chamber 27 from the clamp hydraulic port 33, the operating blade 28b is pushed rearward to separate the unclamping piston 28 from the rear end of the spindle 6. Then, the push rod 16 is moved rearward by the urging force of the urging member 23 to pull in the collet 15, and the pull stud 13b of the tool 13 is clamped by the claw portion 15a.

Further, an unclamping hydraulic port 34 is formed so as to communicate with the outer peripheral surface of the housing body 5 in the enlarged diameter groove 27b on the rear side of the hydraulic chamber 27. A high-pressure oil supply circuit 36 for supplying high-pressure oil and a low-pressure oil supply circuit 37 for supplying low-pressure oil are connected to the unclamping hydraulic port 34, and the circuit is selectively circuited by a switching valve 38 such as a solenoid valve. Either high pressure oil or low pressure oil can be supplied to the unclamping hydraulic port 34.
FIG. 6 is a hydraulic circuit diagram showing the high-pressure oil supply circuit 36 and the low-pressure oil supply circuit 37. The switching valve 38 switches between high-pressure oil and low-pressure oil, and the switching valve 39 switches between clamping and unclamping. .. In the state of the hydraulic circuit diagram shown in FIG. 6, the switching valve 38 is OFF, and the low pressure (low pressure oil) set by the action of the pressure control valve 42 is obtained. When the switching valve 38 is turned on, high pressure (high pressure oil) is obtained. Since the pressure control valve 42 controls the pressure at point C of the A port passage below the set value, oil flows in the state shown in FIG. 6, pressure is generated, and the pressure is lowered to a low pressure. When the switching valve 38 is turned on, the point C becomes the T port (returns to the drain tank), and the pressure becomes 0, so that the pressure becomes smaller than the set pressure. Therefore, the pressure control valve 42 stops lowering the pressure and becomes a high pressure (high pressure oil) of the original pressure, and the high pressure oil is sent to the switching valve 39.

In the unclamping piston 28 in the cylinder 26, an auxiliary air blow flow path 40 is formed around the push rod 16 on the front side portion thereof. Moreover, an airport 41 communicating with the auxiliary air blow flow path 40 is formed on the outer peripheral surface of the housing body 5. The front end opening of the auxiliary air blow flow path 40 faces the rear end opening of the spindle air blow flow path 25 formed in the step portion 16a of the push rod 16. Moreover, as shown in FIG. 4, the step portion 16a of the push rod 16 faces the front surface of the unclamping piston 28 via the gap K in the clamped state of the tool 13.

In FIG. 4, a lubricator 44 is installed in the air blow flow path 43 that supplies air to the airport 41 from the outside, and the lubricating oil can be mixed in the air in the form of mist by the lubricator 44. By turning on the solenoid valve 45 provided in the air blow flow path 43, air mixed with mist-like lubricating oil is supplied to the auxiliary air blow flow path 40 via the airport 41, and the space portion is provided through the spindle air blow flow path 25. It can be supplied to the taper shank 13a of the tool 13 which is filled with 18 and fixed to the taper hole 6a.
At the time of tool replacement, at the timing when the tool 13 is pulled out from the tapered hole 6a of the spindle 6 by the changer arm 53 described later, the space portion 18, the tapered hole 6a and the tool 13 are connected from the airport 41 via the spindle air blow flow path 25. When air containing mist-like lubricating oil is ejected to the taper shank 13a, there is a drawback that it takes time to change tools because it takes time for the air to flow. However, in the present embodiment, by pre-filling the space portion 18 with air before the tool change, the air can be blown immediately when the tool 13 is pulled out.

When low-pressure oil is supplied to the hydraulic chamber 27 through the unclamping hydraulic port 34, the unclamping piston 28 is pushed by the flood control and moves forward, and a relatively weak force is applied to the step portion 16a of the push rod 16. The preparation for compressing the urging member 23 can be completed by pressing with.
On the other hand, when high-pressure oil is supplied to the hydraulic chamber 27 through the unclamping hydraulic port 34, the unclamping piston 28 is pushed by the flood control and moves forward, pushing the step portion 16a of the push rod 16 with a strong force. By moving the collet 15, the collet 15 is moved forward to an unclamped position where the claw portion 15a opens.
A detector 46 for detecting the clamped state and the unclamped state of the tool 13 is installed on the rear end surface of the housing body 5 shown in FIG. 1, and is connected to the rear end of the shaft portion 16b of the push rod 16. The clamped state and the unclamped state can be discriminated by detecting the advancing / retreating position of the subject 47.

FIG. 5 shows the changer arm unit 50 of the automatic tool changer 1. In FIG. 5, the changer arm unit 50 is installed adjacent to the tool 13 mounted in the tapered hole 6a of the spindle 6 of the spindle unit 2. The magazine pot 51 of the tool magazine is installed on the side opposite to the spindle unit 2 with respect to the changer arm unit 50. Although a plurality of magazine pots 51 are arranged, they are omitted except for one in FIG.

In the changer arm unit 50, the drive motor M2 of the changer arm 53 is installed in the cam unit 54 that supports the rotatable changer arm 53. Grippers 55 for gripping the V-flange 13c of the tool 13 are provided at both ends of the changer arm 53.
Then, by rotating the changer arm 53, one gripper 55 grips the new tool 13 in the magazine pot 51, and the other gripper 55 grips the used tool 13 fitted in the tapered hole 6a of the spindle 6. It can be grasped and pulled out. By rotating the changer arm 53 by 180 degrees, the tool 13 can be replaced and a new tool 13 can be fitted into the tapered hole 6a of the spindle 6.

The tool unclamping device 3 of the automatic tool changing device 1 according to the present embodiment has the above-described configuration, and then the unclamping method will be described with reference to the flowchart shown in FIG.
First, the clamping operation of the tool 13 will be described. By switching the switching valve 39 shown in FIG. 6 with the taper shank 13a of the tool 13 inserted in the tapered hole 6a of the spindle 6, the unclamping shown in FIG. 4 is performed. The flood control port 34 is opened, and high pressure oil is charged into the clamp hydraulic port 33 and supplied to the hydraulic chamber 27 from the diameter expansion groove 27a on the front side.
Then, the unclamping piston 28 retracts in the hydraulic chamber 27 due to the oil pressure in the hydraulic chamber 27, abuts on the reduced diameter portion 27c on the rear end side, and stops. As a result, a gap K is created between the step portion 16a of the push rod 16 and the unclamping piston 28. Since the push rod 16 moves rearward by the urging force of the urging member 23 as shown in FIGS. 1 and 2, the collet 15 is pulled into the hole 6b and the pull stud 13b of the tool 13 is pulled in by the claw portion 15a. The taper shank 13a is fitted and held in the taper hole 6a.
In this state, by driving the electric motor M1, the tool 13 and the spindle 6 can be integrally rotated to cut a workpiece (not shown).

Next, automatic tool change (ATC) is performed after the cutting process is completed.
In FIG. 7, as a preliminary step of tool change, the spindle 6, the changer arm 53 of the automatic tool changer 1, and each feed shaft are set at positions where automatic tool change is possible (referred to as orientation). By switching the switching valves 38 and 39 in the cylinder 26 of the spindle unit 2, the clamp hydraulic port 33 is opened, and low-pressure oil is injected from the low-pressure oil supply circuit 37 into the unclamping hydraulic port 34 on the rear side. It is supplied to the hydraulic chamber 27 from the enlarged diameter groove 27b.
The unclamping piston 28 is advanced in the hydraulic chamber 27 by the hydraulic pressure of the low-pressure oil to reduce the gap K, and the unclamping piston 28 abuts on the step portion 16a of the push rod 16 and stops (S101). Moreover, the auxiliary air blow flow path 40 of the unclamping piston 28 and the spindle air blow flow path 25 provided in the step portion 16a of the push rod 16 are connected by the contact between the unclamping piston 28 and the push rod 16.

Next, air containing mist-like lubricating oil is supplied from the air blow flow path 43 to the auxiliary air blow flow path 40 through the airport 41 (S102). This air is sent from the auxiliary air blow flow path 40 of the unclamping piston 28 to the main shaft air blow flow path 25 in the push rod 16, sent to the front of the main shaft 6, and discharged into the space portion 18, and is discharged into the space portion 18. Is filled with air containing mist-like lubricating oil to increase the air pressure.
On the other hand, the changer arm 53 of the automatic tool changer 1 shown in FIG. 5 is located in the vertical direction between the new tool 13 used next to the magazine pot 51 and the used tool 13 mounted on the spindle 6 of the spindle unit 2. Located in the direction of.

Then, substantially at the same time as or before and after the air blow operation (S102) to the space portion 18 of the spindle 6, the changer arm 53 of the automatic tool changer 1 turns 90 degrees counterclockwise (S103) and fits into the spindle 6. The V-flange 13c of the used tool 13 that is held together is gripped by one gripper 55 (S104). Due to the impact at this time, the tool 13 fitted in the tapered hole 6a of the spindle 6 is alleviated from biting. Further, the other gripper 55 of the changer arm 53 grips the V flange 13c of the tool 13 to be used next, which is stored in the magazine pot 51.

Next, in the tool change stage, the low-pressure oil supply circuit 37 is switched to the high-pressure oil supply circuit 36 by the switching valve 38, and the high-pressure oil is charged into the hydraulic chamber 27 through the unclamping hydraulic port 34 (S105). Then, the unclamping piston 28 is further advanced at high pressure to push the push rod 16 at the step portion 16a. As a result, the urging member 23 is compressed to advance the push rod 16. The unclamping piston 28 stops when the nut 31 comes into contact with the rear end surface of the housing body 5.

Since the collet 15 is pushed by the advance of the push rod 16, the claw portion 15a opens in the space portion 18 and the pull stud 13b is released. The tool 13 pushed by the push rod 16 and the collet 15 is released from the fitting with the tapered hole 6a of the spindle 6 and is unclamped.
Further, since the space 18 provided at the rear of the tool 13 is filled with air containing lubricating oil, it contributes to the biting release of the tool 13.

Then, the tool 13 gripped in the tapered hole 6a of the spindle 6 is pulled out by the changer arm 53, and the new tool 13 stored in the magazine pot 51 is also pulled out at the same time (S106). At this time, the air containing the lubricating oil filled in the space 18 is sprayed onto the tapered hole 6a of the main shaft 6 and the tapered shank 13a of the tool 13 to apply mist-like lubricating oil and blow off the adhering dust and the like. Moreover, in order to fill the space 18 with air before the tool change, air containing mist-like lubricating oil is applied to the tapered hole 6a of the spindle 6 and the tapered shank 13a of the tool 13 at the same time as the tool 13 is pulled out. It can be sprayed and keeps up with quick tool change operations.
Next, by further turning the changer arm 53 by 180 degrees and pulling it back (S107), a new tool 13 extracted from the magazine pot 51 can be inserted into the tapered hole 6a of the spindle 6 (S108). Even when a new tool 13 is inserted, air containing mist-like lubricating oil is injected from the spindle air blow flow path 25 and is sprayed onto the taper shank 13a and the taper hole 6a. As a result, it is possible to suppress the tool 13 from biting into the tapered hole 6a. After the insertion of the tool 13 into the tapered hole 6a is completed, the supply of air to the airport 41 is completed (S109).

Next, the unclamping hydraulic port 34 is opened, high-pressure oil is charged into the clamping hydraulic port 33, and the high-pressure oil is supplied from the diameter-expanding groove 27a on the front side to the hydraulic chamber 27 (S110). As a result, the unclamping piston 28 retracts and separates from the push rod 16. The push rod 16 retracts to the clamp position by the urging force of the urging member 23, and similarly clamps the pull stud 13b of the new tool 13 by the claw portion 15a of the collet 15 that retracts.
Then, the changer arm 53 is swiveled back 90 degrees in the opposite direction (S111) to end the automatic tool change cycle.

As described above, according to the tool unclamping device 3 of the automatic tool changing device 1 according to the present embodiment, the push rod 16 is pressed by the unclamping piston 28 with low pressure oil in advance in the step before the tool changing to be an urging member. By completing the compression preparation of 23, the push rod 16 is pushed into the unclamped position at the tool change stage, the tool 13 is opened by the collet 15, and the tool 13 is quickly pulled out by the changer arm 53. It is possible to change tools at a higher speed.
Moreover, the biting of the main shaft 6 of the tool 13 into the tapered hole 6a is released by pressing the push rod 16 through the unclamping piston 28 with low-pressure oil, impact when gripping the tool 13 with the changer arm 53, or the like. Therefore, the tool can be changed quickly in this respect as well.

Further, in the stage before the tool change, the changer arm 53 is used by pre-filling the space 18 on the rear side of the tool 13 fitted in the tapered hole 6a of the spindle 6 with air containing mist-like lubricating oil. Even when the tool is changed instantly in a short time, air containing mist-like lubricating oil is injected from the space 18 in response to the withdrawal of the tool 13 to supply the lubricating oil to the tapered hole 6a and the tool 13 as well as dust and the like. Can be blown away. Moreover, the mist-like lubricating oil injected can reduce the biting of the new tool 13 into the tapered hole 6a.

The tool unclamping device and the tool unclamping method of the automatic tool changing device 1 according to the present invention are not limited to those according to the above-described embodiment, and are appropriately modified or replaced without departing from the gist of the present invention. Etc. are possible. A modification of the present invention will be described below, but the same reference numerals are used for the same or similar members and parts as the tool unclamping device 3 and the tool unclamping method of the automatic tool changing device 1 according to the above-described embodiment. I will explain.

FIG. 8 shows a modified example of the tool unclamping device and the tool unclamping method of the automatic tool changing device 1 according to the above-described embodiment.
In this modification, the cylinder 26 supplies low-pressure oil to the hydraulic chamber 27, advances the unclamping piston 28 to press the rear end of the push rod 16, and creates a space from the auxiliary air blow flow path 40 through the spindle air blow flow path 25. After confirming that the portion 18 was filled with air containing mist-like lubricating oil in the step S112 in the flowchart of FIG. 8, the changer arm 53 was rotated 90 degrees to grip the tool 13.
As a means for confirming the filling of air into the space portion 18, for example, a timer or the like may be used to check the passage of a predetermined time from the start of ejection of the air blow to the filling, or the air pressure in the space portion 18 is detected. A sensor or the like may be installed.
As a result, the replacement of the tool 13 by the changer arm 53 and the injection of air from the space portion 18 can be reliably linked.

Further, in the present embodiment, when the space portion 18 is filled with air containing mist-like lubricating oil before the tool is replaced, the main shaft of the push rod 16 is supplied from the auxiliary air blow flow path 40 provided in the unclamping piston 28. The space portion 18 between the tapered hole 6a of the main shaft 6 and the hole portion 6b at the rear portion is sent to fill the space via the air blow flow path 25, but the present invention is not limited to such a configuration.
For example, without providing the auxiliary air blow flow path 40 in the unclamping piston 28, an air port 41 connected to the spindle air blow flow path 25 is provided on the outer peripheral surface of the housing body 5, and mist-like lubricating oil is supplied from the air blow flow path 43. The containing air may be supplied. Even in this case, the space portion 18 can be filled with air before the tool change. The air to be injected does not have to contain lubricating oil.
In the present invention, the push rod 16 and the collet 15 are included in the tool gripping member, the unclamping piston 28 is included in the unclamping actuating member, and the switching valves 38 and 39 are included in the switching member.

1 Automatic tool changer
2 Spindle unit 3 Tool unclamping device 5 Housing body 6 Spindle 6a Tapered hole 13 Tool 13a Tapered shank 13b Pull stud 15 Collet 16 Push rod 18 Space 23 Basis member 25 Spindle air blow flow path 27 Hydraulic chamber 28 Unclamping piston 33 Clamping hydraulic port 34 Unclamping hydraulic port 36 High pressure oil supply circuit 37 Low pressure oil supply circuit 38 Switching valve 40 Auxiliary air blow flow path 41 Airport 51 Magazine pot 53 Changer arm K Gap

Claims (7)

A hollow spindle to which a tool is attached to the tip, and a tool gripping member that is movably arranged in the spindle in the central axis direction and selectively clamps and unclamps the tool by moving in the central axis direction. An urging member that urges the tool gripping member in the tool clamping direction, an unclamping actuating member that moves the tool gripping member in the unclamping direction, and an unclamping actuating member provided to supply hydraulic pressure. In a tool unclamping device for a machine tool provided with a hydraulic chamber that presses the tool gripping member in the unclamping direction.
A low-pressure oil supply circuit that supplies low-pressure oil to the hydraulic chamber and presses the tool gripping member and the urging member in the unclamping direction by the unclamping operating member.
A high-pressure oil supply circuit that supplies high-pressure oil higher than low-pressure oil to the hydraulic chamber and pushes the tool gripping member by the unclamping operating member to unclamp the tool.
A switching member for switching between the low-pressure oil and the high-pressure oil and supplying the oil to the hydraulic chamber is provided.
Low-pressure oil is supplied to the hydraulic chamber in the stage prior to tool change, and the tool gripping member is pressed at low pressure via the unclamping actuating member to prepare the urging member for compression, and the hydraulic pressure is prepared in the tool change stage. A tool unclamping device for a machine tool, characterized in that high-pressure oil is supplied to a chamber and the tool gripping member is pushed through the unclamping operating member to unclamp the tool. A spindle air blow flow path provided on the spindle and supplying air or air containing lubricating oil is provided in a space behind the tool holding portion of the spindle.
The tool unclamping device for a machine tool according to claim 1, wherein the space is filled with the air through the spindle air blow flow path before the tool change. An auxiliary air blow flow path provided in the unclamping actuating member and connectable to the spindle air blow flow path is further provided.
2. Claim 2 in which the unclamping actuating member is pushed to connect the auxiliary air blow flow path to the spindle air blow flow path in a stage prior to the tool change so that the air is filled in the space. Tool unclamping device for machine tools described in. A changer arm for gripping a tool attached to the spindle for automatic replacement is provided, and the impact of gripping the tool with the changer arm releases the bite of the spindle with respect to the tool. The tool unclamping device for a machine tool according to any one of 3 to 3. A hollow spindle to which a tool is attached to the tip, and a tool gripping member that is movably arranged in the spindle in the central axis direction and selectively clamps and unclamps the tool by moving in the central axis direction. An urging member that urges the tool gripping member in the clamping direction, an unclamping actuating member that moves the tool gripping member in the unclamping direction, and an unclamping actuating member provided on the unclamping actuating member by supplying hydraulic pressure. In the tool unclamping method of a machine tool provided with a hydraulic chamber that presses the tool gripping member in the unclamping direction.
By supplying low-pressure oil to the hydraulic chamber in the stage prior to tool replacement, the tool gripping member is pressed at low pressure via the unclamping actuating member to end the preparatory operation for compressing the urging member, and the tool is completed. A tool of a machine tool characterized in that the low-pressure oil supplied to the hydraulic chamber is switched to high-pressure oil at the replacement stage, and the tool gripping member is pushed through the unclamping operating member to unclamp the tool. Unclamping method. Prior to the tool change, low-pressure oil is supplied to the hydraulic chamber to press the unclamping operating member against the tool gripping member at low pressure, and air or air mixed with lubricating oil is applied to the tool holding portion on the spindle. The process of supplying and filling the space of
The tool unclamping method for a machine tool according to claim 5, wherein the air in the space is ejected to the tool and the tool holding portion by pulling out the tool from the spindle by the changer arm at the tool changing stage. After gripping the tool mounted on the spindle with the changer arm, the low pressure oil supplied to the hydraulic chamber is switched to high pressure oil, and the tool gripping member is pushed through the unclamping actuating member to unlock the tool. The tool unclamping method for a machine tool according to claim 6, wherein the tool is clamped.

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