JP2023182929A - Tool changing mechanism for automatic tool changer - Google Patents

Abstract

To provide a tool changing mechanism for an automatic tool changer, which executes accurate tool changing.SOLUTION: The tool changing mechanism installed in the automatic tool changer for changing and conveying tools between a tool magazine which stores a plurality of tools and a tool main spindle which carries out workpiece machining comprises: tool gripping means for gripping the tools through an opening/closing operation of a movable member assembled to a fixed member so as to be displaceable; an elongatable actuator that moves the tool gripping means back and forth; a holding member that holds the tools gripped by the tool gripping means through changing carried out at the stroke end of the actuator; and transmission means that is provided at the stroke end of the actuator and that is for transmitting, after holding of the tools by the holding member, an operation of the actuator to cause the movable member to carry out the opening operation.SELECTED DRAWING: Figure 8

Description

The present invention relates to a tool transfer mechanism of an automatic tool changer that accurately transfers tools.

Machine tools that perform various types of machining using a plurality of tools are equipped with an automatic tool changer, which automatically exchanges a predetermined tool with a spindle device when changing the machining content. Patent Document 1 listed below also discloses a machining center equipped with a tool magazine for automatic tool exchange. The tool magazine is provided with a tool cap conveying means, and is provided with a magazine plate having a plurality of recesses formed along the outer periphery at equal intervals on the circumference for accommodating the tool caps. The slide bracket is configured to reciprocate between the tool cap conveyance position and the exchange position of the tool magazine, with the tool cap sandwiched between the cylinders.

Japanese Patent Application Publication No. 9-248731

The conventional automatic tool changer uses a cylinder to move the tool cap between the tool cap transfer position and the tool cap exchange position. The mechanism for transferring the tools used is not clear. In reality, various tool transfer mechanisms exist to ensure reliable tool transfer, but automatic tool transfer requires accuracy. Further, accuracy in transferring tools requires accurate assembly of related members, and adjustment work before driving the automatic tool changer becomes a burden.

Therefore, an object of the present invention is to provide a tool transfer mechanism for an automatic tool changer that accurately transfers tools.

The tool transfer mechanism of an automatic tool changer according to the present invention is a tool provided in an automatic tool changer that transfers and conveys tools between a tool magazine storing a plurality of tools and a tool spindle for machining a workpiece. The transfer mechanism includes a tool gripping means for gripping a tool by opening and closing operations of a movable member displaceably assembled with respect to a fixed member, an extendable actuator for reciprocating the tool gripping means, and the tool gripping means. a holding member for holding a tool gripped by the means by transfer performed at the stroke end of the actuator; and a holding member provided at the stroke end of the actuator for transmitting the operation by the actuator after the tool is held by the holding member. and a transmission means for opening the movable member.

According to the above configuration, the automatic tool changer transfers tools to a predetermined position between a tool magazine storing a plurality of tools and a tool spindle for machining a workpiece. In the step of returning the tool to the tool magazine, when the tool is transferred to the holding member at the stroke end of the actuator, the opening operation of the tool gripping means comprising a fixed member and a movable member is performed by the actuator after the tool is held by the holding member. Since the movement is transmitted by the transmission means, the tool can be transferred accurately.

FIG. 2 is a front view showing the internal structure of the multitasking machine. 1 is a perspective view showing a multi-tasking machine with an automatic tool changer added thereto; FIG. FIG. 2 is a perspective view showing an automatic tool changer. It is a perspective view showing the front and back shifters which constitute a tool conveyance part. FIG. 3 is a perspective view showing an upper and lower shifter that constitutes a tool transport section. It is a side view which showed the 1st tool transfer mechanism which returns a tool to a tool magazine. This figure shows different states of the same tool transfer mechanism as in FIG. 6 step by step. This figure shows different states of the same tool transfer mechanism as in FIG. 6 step by step. 9 is a perspective view showing the relationship between the pusher and the tool holder in a state corresponding to FIG. 8. FIG. FIG. 6 is a diagram showing a separated state when the tool holder and the air cylinder are attached and detached. FIG. 6 is a diagram showing a state in which the tool holder and the air cylinder are attached and detached. FIG. 6 is a diagram showing a locked state when the tool holder and the air cylinder are attached and detached.

An embodiment of the tool transfer mechanism of the automatic tool changer according to the present invention will be described below with reference to the drawings. First, the tool transfer mechanism of this embodiment is used in an automatic tool changer installed in a machine tool shown in FIG. FIG. 1 is a front view of the internal structure of a multitasking machine. This multitasking machine 1 is an opposed two-axis lathe in which a first workpiece spindle device 3 and a first turret device 5, and a second workpiece spindle device 4 and a second turret device 6 are arranged symmetrically. This multitasking machine 1 is provided with a tool spindle device 2 at the center of the machine body. The tool spindle device 2 performs machining on a work W gripped by the spindle chucks 11 of the first work spindle device 3 and the second work spindle device 4 in order to perform processing that is difficult to perform on a lathe.

The tool spindle device 2 is capable of machining workpieces using various tools, and the multitasking machine 1 is provided with an automatic tool changer for replacing such tools T. FIG. 2 is a perspective view showing the multitasking machine 1 including the automatic tool changer. In this automatic tool changer 8, a tool magazine 15 storing a plurality of tools T is arranged at the upper front of the machine body, and the tools are arranged vertically so as to be located in the center of the machine body, while the tool magazine 15 spreads in the horizontal direction. A transport section 16 is configured. Therefore, the tool T indexed in the tool magazine 15 is configured to be carried by the tool transport section 16 to the spindle head 13 of the tool spindle device 2.

Next, FIG. 3 is a perspective view showing the automatic tool changer 8 from the back side of the machine body (the opposite side of FIG. 2). A tool magazine 15 that stores a plurality of tools T is rotatably hung by an endless roller chain 21 so as to form an oval shape, and a plurality of tools T are suspended from the tool magazine 15 so as to be lined up in a line. The feed amount of the roller chain 21 in the circumferential direction is adjusted by controlling the rotation of the indexing servo motor 22, so that the tool T corresponding to the indexing position P1 provided at the center is conveyed.

The tool T at the index position P1 is carried to the tool spindle device 2 by the tool transport section 16, and FIG. 4 is a perspective view showing the front and rear shifters that constitute the tool transport section 16. 2 is a perspective view showing a vertical shifter that also constitutes the tool transport section 16. FIG. A removable tool holder 23 is attached to the tool T, which allows the tool T to be held by the roller chain 21 and transferred to the tool transport section 16. The tool holder 23 is a member that fits into the head portion of the tool T. Note that although the tools T shown in each drawing are all expressed in a cylindrical shape, this only represents an area in which various tools T can fit.

The roller chain 21 of the tool magazine 15 has a plurality of U-shaped tool holders 31 arranged at regular intervals. The tool holder 31 is adapted to be hooked by groove-shaped grip portions 231 formed on both sides of the tool holder 23 (see FIG. 7). Furthermore, a spring holder 32 made of a plate spring bent in a U-shape is attached below the tool holder 31. The spring holder 32 prevents wobbling by holding the tool holder 23 housed in the tool holder 31 with spring force. The front and rear shifter 25 moves the tool T in the horizontal X-axis direction between the index position P1 on the roller chain 21 side and the vertical transfer position P2 by the vertical shifter 26.

The front and rear shifter 25 is assembled to the top plate 33 of the tool magazine 15. The front and rear shifter 25 is an air cylinder 35 with a piston rod 351 horizontally protruding as an actuator, and a connecting head 36 is attached to the tip of the piston rod 351. Two guide rods 34 parallel to the air cylinder 35 are provided, each passing through a support block 37 and having a distal end portion attached to a connecting head 36. The connecting head 36 is configured to move in the front-rear direction (X-axis direction), which is the direction in which the air cylinder 35 expands and contracts, and can be attached to and detached from the tool holder 38 as described later. The tool holder 38 is for gripping and holding the tool T so that it can be moved between the front and rear shifters 25 and the upper and lower shifters 26.

The vertical shifter 26 moves the tool T in the vertical direction by changing the tool holder 38. The tool holder 38 is integrally formed with a gripping block 55 in which a U-shaped portion 551 is formed. The holder 38 can be held. That is, the clamp portion 40 of the vertical shifter 26 is configured such that a clamp pin 41 protruding downward through a cylindrical member is moved up and down by an air cylinder 42, and when the clamp pin 41 is pulled in, the gripping block 55 can be gripped between the cylindrical member and the clamp pin 41. It looks like this.

The clamp part 40 is assembled to the upper beam of the elevating frame 43, and the tool T held via the tool holder 38 is housed within the frame. The elevating frame 43 slides on a vertical guide rail 44 to move up and down, and the vertical shifter 26 uses a ball screw mechanism that converts the output of the elevating servo motor 45 into linear motion. Therefore, by controlling the drive of the elevating servo motor 45, the elevating and lowering position of the elevating frame 43, that is, the position of the tool T, is controlled. A tool changer 27 shown in FIG. 3 is provided at the lowered position in order to transfer the tool T between the spindle head 13 and the vertical shifter 26.

The tool changer 27 is provided with a tool change arm 47, on which chuck claws for gripping the tool T are formed at both ends. The rotation of a turning servo motor 48 is transmitted to the tool exchange arm 47 via a cam device 49 . The cam device 49 is composed of a grooved cam, a globoidal cam, etc., which converts the rotation input from the turning servo motor 48 into rotational motion and vertical motion and transmits the same to the output shaft connected to the tool changing arm 47. has been done. In the tool changer 27, when the shutter 46 is lowered, the tool T can be exchanged with respect to the spindle head 13 using the tool exchange arm 47.

The automatic tool changer 8 includes a tool magazine 15, a front and rear shifter 25, a top and bottom shifter 26, and a tool changer 27, and is configured to transport the tools T through each stage of transfer. Therefore, in order to perform appropriate tool exchange, it is required that the tools T at each stage be reliably transferred. First, the first tool transfer mechanism between the tool magazine 15 and the front and rear shifter 25 will be explained. In particular, the tool transfer mechanism for returning the tool T to the tool magazine 15 will be explained.

As mentioned above, the roller chain 21 of the tool magazine 15 has a tool holder 31 and a spring holder 32, and especially when returning the tool T, it is necessary to ensure that the tool holder 23 fits into the spring holder 32. No. FIG. 6 is a side view showing the first tool transfer mechanism when returning the tool T to the tool magazine 15.

First, the tool holder 38 is displaced in the front-rear direction (X-axis direction) with respect to an L-shaped fixed block 51 by a support pin 53 formed integrally with a plate-shaped movable block 52, as shown in the figure. It is possible to open and close the tool holder 23 by gripping and releasing it. The support pin 53, which is movable within the fixed block 51, is axially biased by a clamp spring 54, and the movable block 52 is always drawn toward the fixed block 51. The tool T is gripped by the tool holder 38 by fitting the clamp claws 511, 521 (see FIG. 9) of the fixed block 51 and the movable block 52 into the clamp groove 233 of the tool holder 23.

When transferring the tool T from the front/rear shifter 25 to the tool magazine 15, it is preferable that the tool holder 23 is reliably held by the spring holder 32 and then released from the tool holder 38. If the tool holder 38 moves to the opening operation before the tool holder 23 is fitted into the spring holder 32, the retracting force by the air cylinder 35 will not be transmitted to the tool holder 23, and the tool holder 23, that is, the tool T, will not be placed in the correct position. This is because it cannot be returned to. If the roller chain 21 rotates without the tool T returning to the correct position, the tool T will not follow the correct trajectory and a collision will occur. In order to solve this problem, the first tool transfer mechanism is configured to return the tool T to an accurate position with respect to the tool magazine 15.

The connecting head 36 at the tip of the piston rod 351 is configured to be attached and detached via a locking mechanism on the tool holder 38 side. Therefore, when returning the tool T from the vertical transfer position P2 shown in FIG. It happens. At this time, it is necessary to release the tool holder 23 from the tool holder 38 after the tool holder 23 is securely held by the spring holder 32.

Therefore, in order to adjust the timing of releasing the tool holder 23, a pusher 60 is provided on the air cylinder 35 side. The pusher 60 pushes the support pin 53 of the tool holder 38 to separate the movable block 52 from the fixed block 51 against the urging force of the clamp spring 54. Here, FIGS. 7 and 8 show step-by-step the process of the first tool transfer mechanism, which is the same as that shown in FIG. 6, particularly at the contraction side stroke end of the air cylinder 35. 9 is a perspective view showing the relationship between the pusher 60 and the tool holder 38 in a state corresponding to FIG. 8.

In the pusher 60, a base block 61 is fixed to an assembly block 58 that attaches the air cylinder 35 to the top plate 33, and a release lever 62 having a horizontal pin inserted therein is swingably supported. In the release lever 62, a working pin 63 projects laterally from a portion projecting upward from the base block 61, and an extrusion roller 64 is pivotally supported at a portion inside the bifurcated base block 61. An operating block 39 is fixed to the tip of the piston rod 351, and is configured to be hooked onto the operating pin 63 when the air cylinder 35 moves in the contraction direction. In particular, the working pin 63 and the operating block 39 are designed to contact each other by a very small distance (for example, 4 mm) at the stroke end of the air cylinder 35.

Sliding rods 65 pass through both lower sides of the bifurcated base block 61, and these two sliding rods 65 are formed integrally with a receiving block 66 on the tool holder 38 side. Two push pins 67 are horizontally protruded from the receiving block 66, and each push pin 67 is positioned coaxially with the two support pins 53 inside the tool holder 38. The insertion hole of the fixed block 51 into which the support pin 53 is installed has an opening through which the push pin 67 enters to push the support pin 53. The pressing force is an output from the air cylinder 35 that swings the release lever 61, and is transmitted to the receiving block 66 via the pushing roller 64.

Therefore, in the first tool transfer mechanism, when returning the tool T from the vertical transfer position P2 in FIG. The tool T moved. The tool holder 23 at the stroke end of the air cylinder 35 shown in FIG. In the first tool transfer mechanism, the tool holder 23 is strongly gripped by the tool holder 38 up to this stage, so the tool holder 23 is reliably fitted into the spring holder 32.

By contracting the air cylinder 35 further by about 4 mm from the state shown in FIG. 7, the tool holder 23 in the tool holder 38 shown in FIG. 8 is released. That is, as shown in FIG. 9, the working pin 63 to which the operating block 39 is applied is pushed in the direction of contraction of the air cylinder 35, and the release lever 61 swings accordingly, moving in the opposite direction to the upper working pin 63. The lower extrusion roller 64 is displaced. Note that at this time, the stopper pin 68 is brought into contact with the assembly block 58 side, and further contraction of the piston rod 351 is restricted.

The receiving block 66 is pushed by the displacement of the push-out roller 64, and the support pin 53 is further pushed by the push pin 67. By pushing the support pin 53, the movable block 52 moves in a direction away from the fixed block 51 against the biasing force of the clamp spring 54, and the tool holder 23 that was gripped by the clamp claws 511 and 521 is released. be done. In this way, the transfer of the tool T from the front and rear shifter 25 to the roller chain 21 side of the tool magazine 15 is completed.

Therefore, according to the first tool transfer mechanism that returns the tool T to the tool magazine 15, the tool holder 38 holds the tool holder 23 until the tool holder 23 is securely held in the spring holder 32. Maintained. Therefore, even if the tool T is returned to the correct position by transferring it to the tool magazine 15 and the roller chain 21 rotates when indexing another tool T, the returned tool T will not become an obstacle. Never. Further, the first tool transfer mechanism has the pusher 60 pushing the support pin 53 of the tool holder 38, and the above effect can be achieved with its simple configuration.

Next, a second tool transfer mechanism for transferring tools between the front and rear shifters 25 and the upper and lower shifters 26 will be described. In particular, this is a mechanism for attaching and detaching the air cylinder 35 and tool holder 38 in the front and rear shifter 25. 10 to 12 are plan views showing each state in which the tool holder 38 and the air cylinder 35 are attached and detached. FIG. 10 shows the separated state, FIG. 11 shows the attached state, and FIG. 12 shows the locked state. be. First, two guide rods 34 parallel to the air cylinder 35 are connected by a connecting head 36 at the tip side of the piston rod 351. The tip of the guide rod 34 is connected to the connecting head 36 by a pin 71, and the support blocks 37 that slidably support the guide rod 34 are each rotatably attached to the top plate 33 by a pivot shaft 371. It is being

The guide rod 34 and the connecting head 36 form a parallel link mechanism by connecting rotating shafts at four points (pin 71 and pivot shaft 371). Therefore, the connecting head 36, which is displaced in the X-axis direction by the expansion and contraction operation of the air cylinder 35, can move while maintaining a posture perpendicular to the X-axis. Therefore, the piston rod 351 and the connecting head 36 are connected with a degree of freedom, and a protrusion 361 formed on the connecting head 36 side is inserted into the vertical groove 391 formed on both sides of the operation block 39. It's fitted.

The connecting head 36 has a fitting hole 363 opened in the movement direction (X-axis direction) in the center thereof, and fitting recesses 365 are formed on both sides of the fitting hole 363. The connecting head 36 is positioned with the tool holder 38 using a fitting recess 365 and connected through a fitting hole 363. In the tool holder 38, a locking block 72 is fixed onto the gripping block 55 (see FIG. 6), and a fitting portion that fits into the fitting hole 363 is formed there. Furthermore, a positioning pin 73 that fits into the fitting recess 365 projects horizontally (in the X-axis direction) from the locking block 72 .

The fitting hole 363 of the connecting head 36 has a convex portion 367 formed so that the width on the distal end side becomes narrow, and the fitting portion of the locking block 72 has a convex portion 367 so as to be in sliding contact with the convex portion 367. Moving pieces 74 are attached to both sides. Further, a movable pin 75 is provided in a horizontal hole formed in the fitting portion of the locking block 72, and the spherical tip portion is configured to move in and out in a direction perpendicular to the moving direction of the connecting head 36. ing. A lock pin 76 is inserted into the lock block 72 to displace the two movable pins 75 symmetrically. The lock pin 76 is formed with an annular constriction 761 with a narrowed diameter, and when the movable pin 75 enters the constriction, the lock pin 76 becomes unlocked.

The lock pin 76 is biased by a spring 77 in the direction of extension of the air cylinder 35 within the lock block 72 and abuts against a stopper 82 fixed to a support plate 81 . Further, a locking cylinder 83 is provided on the support plate 81, and a piston rod biased by a spring is pressed against the locking block 72 in the contraction direction of the air cylinder 35.

In the second tool transfer mechanism, the piston rod 351 is extended by the extension operation of the air cylinder 35 shown in FIG. 10 from the contracted state, and the connecting head 36 is moved as shown by the dashed line. The connecting head 36 moves forward without tilting its posture while being supported at both ends by the guide rods 34 forming a parallel link, and as shown in FIG. It relatively enters the fitting hole 363. Further, on the distal end surface of the connecting head 36, the positioning pin 73 of the locking block 72 is relatively fitted into the fitting recess 365.

By the way, the connection head 36 during such connection may be misaligned in the lateral direction (Y-axis direction). However, in the second tool transfer mechanism, the connecting head 36 can be displaced laterally by the parallel link while maintaining a posture perpendicular to the expansion/contraction direction of the air cylinder 35, and the connecting head 36 can be displaced laterally by the parallel link. The locking block 72 is aligned with the fitting portion. Therefore, even if there is a lateral shift in the coupling head 36, smooth coupling can be achieved by correcting the position of the coupling head 36 when fitting together. In the same manner, the positioning pin 73 fits into the fitting recess 365.

The extension operation of the air cylinder 35 is stopped when the connecting head 36 is pressed against the locking block 72, and the tool T can then be transferred between the front/rear shifter 25 and the upper/lower shifter 26. When the tool T is moved by the vertical shifter 26, the gripping block 55 is held by the clamp pin 41 (see FIG. 5) inserted into the U-shaped portion 551. Therefore, when the gripping block 55 is maintained in the state shown in FIG. 11 and the air cylinder 35 is retracted, the connecting head 36 is removed from the locking block 72 and returned to the position shown in FIG. 10. In this way, the tool T is transferred to the vertical shifter 26, and the next operation of transporting it to the tool changer 27 can be started immediately.

Conversely, when the tool T is received from the vertical shifter 26 and returned to the tool magazine 15, the gripping block 55 is not restrained, so that the connection head 36 and the tool holder 38 are locked. That is, as shown in FIG. 12, when the connecting head 36 moves toward the tool magazine 15 as the air cylinder 35 contracts, the locking block 72 is pushed by the locking cylinder 83 and moves in the same direction. At this time, since the lock pin 76 is fixed to the support plate 81, the movable pin 75 is removed from the constricted portion 761 and pushed outward by the relatively moved lock pin 76. Then, the convex portion 367 of the connecting head 36 is caught on the movable pin 75, and the connecting head 36 enters a locked state in which it cannot be removed from the locking block 72. The tool T held in the tool holder 38 is thus transferred from the up/down shifter 26 to the front/back shifter 25 and transported to the tool magazine 15.

Therefore, in the second tool transfer mechanism, the connecting head 36 is configured as a part of the parallel link, thereby reducing the labor-intensive adjustment work regarding the fitting positions of the locking block 72 and the positioning pin 73. is now possible. In addition, in the second tool transfer mechanism, the fitting portion of the locking block 72 provided with the sliding piece 74 and the positioning pin 73 protrude in the expansion/contraction direction (X-axis direction) of the air cylinder 35, and the connecting head 36 automatically Since it can be attached and detached by moving, there is no need to perform a separation operation on the upper and lower shifter 26 side.

Although one embodiment of the present invention has been described above, the present invention is not limited to this, and various changes can be made without departing from the spirit thereof.
For example, in the embodiment described above, a tool transfer mechanism incorporated in the automatic tool changer 8 in the multitasking machine 1 has been described, but a different automatic tool changer may be used.
Further, in the embodiment, an air cylinder is shown as an example of the actuator, but a hydraulic cylinder may be used as the same fluid pressure cylinder.

1... Multi-tasking machine 2... Tool spindle device 8... Automatic tool changer 15... Tool magazine 16... Tool transport section 23... Tool holder 25... Back and forth shifter 26... Up and down shifter 27... Tool changer 31... Tool holder 32... Spring holder 35 ...Air cylinder 34...Guide rod 38...Tool holder 51...Fixed block 52...Movable block 60...Pusher 62...Release lever T...Tool

Claims (5)

A tool transfer mechanism provided in an automatic tool changer that transfers and conveys tools between a tool magazine that stores a plurality of tools and a tool spindle that processes a workpiece,
tool gripping means for gripping the tool by opening and closing operations of a movable member displaceably assembled with respect to the fixed member;
an extendable and retractable actuator that reciprocates the tool gripping means;
a holding member that holds the tool gripped by the tool gripping means by transferring the tool at a stroke end of the actuator;
a transmission means that is provided at a stroke end of the actuator and transmits the operation by the actuator to open the movable member after the tool is held by the holding member;
A tool transfer mechanism for an automatic tool changer. 2. The tool transfer mechanism of an automatic tool changer according to claim 1, further comprising a tool holder that is fitted into a head portion of the tool and is gripped by the tool gripping means and held by the holding member. The holding member is a spring holder made of a plate spring provided on an endless roller chain constituting the tool magazine, and the transmission means is such that a release lever pivotally supported in a swingable manner is configured to hold the tool in the spring holder. 3. The tool transfer mechanism of an automatic tool changer according to claim 1, wherein the tool transfer mechanism of an automatic tool changer according to claim 1 or 2, is swung by the retracting operation of the actuator after the retracting operation, and causes the movable member of the tool gripping means to perform an opening operation. The tool gripping means is such that the movable member integrally formed with a support pin movable within the fixed member is always drawn toward the fixed member by a clamp spring that biases the support pin, and 3. The tool transfer mechanism of an automatic tool changer according to claim 1, wherein the transmission means is such that the rocking of the release lever pushes and displaces the support pin against the biasing force of the clamp spring. . The actuator is a fluid pressure cylinder, an operating member is fixed to a piston rod of the fluid pressure cylinder, and the transmission means is configured to cause the operating member to swing the release lever via a working pin fixed to the release lever. 4. The tool transfer mechanism of an automatic tool changer according to claim 3.

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