JP2020069553A - Tool changer and machine tool - Google Patents

Abstract

To provide a tool changer which can surely determine rotational position displacement of a tool magazine.SOLUTION: A tool changer 2 includes: a tool magazine 10 which has a plurality of tool holders 8 that are annularly arranged and each holds a tool T that can be mounted on a main shaft 3 of a machine tool 1, and is rotated so as to deliver and receive the tool T between the main shaft 3 and the arbitrary tool holder 8; and a position deviation detection device 12 which detects rotational position deviation to the main shaft 3 of the tool magazine 10, in which the tool holder 8 has a body 13 in close with a side face of the tool T, and a pair of arms 14 which extend from the body 13, are energized so as to sandwich the tool T and have a contact part 17 projecting inward so as to contact with the side face of the tool T provided on its tip side, and the position displacement detection device 12 has a rotation detection part 18 which detects rotation of the main shaft 3, and a determination part 19 which determines position displacement of the tool magazine 10 on the basis of a rotation amount of the main shaft 3 detected by the rotation detection part 18 when the tool T is delivered to the tool holder 8 from the main shaft 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tool changing device and a machine tool.

  BACKGROUND ART Conventionally, a machine tool including a tool changing device that automatically changes a tool mounted on a spindle has been widely used. As one aspect of the tool changing device, a plurality of tool holders each capable of holding a tool have a turret-shaped tool magazine arranged in an annular shape, and by rotating the tool magazine, any tool holder can be used as a spindle. A swivel type device is known in which a tool is attached to and detached from each other so as to be opposed thereto. In such a swivel type tool changing device, it is required to accurately position the tool holder with respect to the spindle. For this reason, there has been proposed a technique for detecting a rotational displacement of the tool magazine, that is, a positioning error of the tool magazine with respect to the spindle of the tool holder in the swivel type tool changer.

  For example, Patent Document 1 discloses a method of determining a rotational displacement of a tool magazine by detecting a load current of a servo motor that rotationally positions the tool magazine. If the tool magazine is rotationally displaced, that is, if there is an offset in the internal position information of the servo mechanism, the spindle moves the tool holder to the correct position through the tool when replacing the tool after positioning the tool holder. Rotate the tool holder slightly so that At this time, the servo motor of the tool magazine generates a driving force in an attempt to hold the rotational position initially positioned based on the internal position information. Therefore, by detecting the load of the servo motor, the rotational displacement of the tool magazine can be detected.

JP, 2011-173197, A

  However, in the method described in Patent Document 1, when a plurality of tools are arranged in the tool magazine with an unbalanced weight, the load of the servo motor varies depending on the rotation position of the tool magazine, so that the rotation position of the tool magazine is misaligned. It cannot be detected reliably.

  An object of the present invention is to provide a tool changing device and a machine tool capable of reliably detecting a rotational displacement of a tool magazine.

  (1) A tool exchanging device (for example, a tool exchanging device 2) according to the present invention is arranged in an annular shape, and has a plurality of tool holders (for example, a tool holder to be described later) that hold tools that can be mounted on a spindle of a machine tool. 8), and a tool magazine (for example, a tool magazine 10 described later) that rotates so as to transfer the tool between the spindle and any tool holder, and a rotational position of the tool magazine with respect to the spindle. A position deviation detection device (for example, a position deviation detection device 12 described later) that detects a deviation, and the tool holder includes a main body (for example, a holder main body 13 described later) that is close to a side surface of the tool, and the main body. An abutting portion (for example, an abutting portion 17 described later) that is biased so as to sandwich the tool and that projects inward so as to abut the side surface of the tool. And a pair of arms (for example, an arm 14 described below), and the positional deviation detection device includes a rotation detection unit (for example, a rotation detection unit 18 described below) that detects rotation of the spindle, and It has a determination unit (for example, a determination unit 19 described later) that determines the positional deviation of the tool magazine based on the rotation amount of the spindle detected by the rotation detection unit when delivering the tool to the tool holder.

(2) In the tool exchanging device according to (1), the determining unit shifts the rotational position of the tool magazine when the maximum rotation amount of the spindle when delivering the tool is equal to or more than a preset threshold value. It may be determined that the tool magazine is present, and the direction of displacement of the tool magazine may be determined from the rotation direction when the rotation amount of the spindle is maximized.

(3) The machine tool (for example, the machine tool 1 described later) according to the present invention can be equipped with the tool changing device of (1) or (2) and the tool (for example, the tool T described later) by the tool changing device. And a main spindle (for example, a main spindle 3 described later).

  According to the present invention, it is possible to reliably detect the rotational displacement of the tool magazine.

It is a block diagram which shows the machine tool which concerns on one Embodiment of this invention. It is a perspective view which shows the tool change device of the machine tool shown in FIG. FIG. 3 is a front view of the tool changing device shown in FIG. 2. FIG. 4 is a plan view showing a tool holder of the tool changing device shown in FIG. 3. 3 is a flowchart showing a procedure of processing for detecting a rotational displacement of a tool magazine of the tool changing device shown in FIG. 2.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a machine tool 1 according to an embodiment of the present invention. FIG. 2 is a perspective view showing the tool changing device 2 of the machine tool shown in FIG. FIG. 3 is a front view of the tool changing device 2 shown in FIG.

  The machine tool 1 shown in FIG. 1 includes a tool exchanging device 2 shown in detail in FIGS. 2 and 3, a spindle 3 on which a tool T is detachably attached by the tool exchanging device 2, and a table 4 which holds a work piece machined by using the tool T. With. The main spindle 3 is rotatably held by a main spindle head 6 that is vertically movable in a main spindle guide 5 that is movable relative to the table 4 in the horizontal direction. The main spindle 3 extends in the vertical direction, a tool T is attached to the lower end thereof, and can be rotated by a motor in the main spindle head 6. Each component of the machine tool 1 is controlled by the main controller 7. The tool changing device 2 is itself an embodiment of the tool changing device according to the present invention.

  The tool changing device 2 includes a rotatable tool magazine 10 having a plurality of tool holders 8 arranged in an annular shape and a magazine body 9 having the plurality of tool holders 8 arranged on the outer periphery thereof, and an arbitrary tool holder 8 A servo motor 11 for rotating the tool magazine 10 so that the tool T can be passed between the main shaft 3 and the main shaft 3 and a position deviation detection device 12 for detecting a rotational position deviation of the tool magazine 10.

  In the tool magazine 10, the lower side is close to the spindle 3 so that the tool holder 8 arranged at the lower end can transfer the tool T to and from the spindle 3, and the other parts are other constituent elements such as the spindle head 6. The upper side is inclined so as to be separated from the spindle head 6 so as not to interfere with. Further, the tool changing device 2 can move the tool holder 8 facing the spindle 3 toward and away from the spindle 3 in order to assist the transfer of the tool T between the tool holder 8 and the spindle 3. As described above, a mechanism for adjusting the inclination angle of the rotating shaft of the tool magazine 10 may be further provided.

  The tool holders 8 are each configured to hold a tool T that can be mounted on the spindle 3 of the machine tool 1. Specifically, as shown in FIG. 4, the tool holder 8 is held by the magazine body 9 of the tool magazine 10 and extends from the holder body 13 and the holder body 13 that is arranged so as to be close to the side surface of the tool T. A pair of arms 14 that sandwich the tool T, a spring 15 that urges the arms 14 to swing inward, and a key groove K of the tool T so that the rotational position of the tool T around the spindle 3 can be determined. And a key 16 to be engaged.

  The arm 14 is provided with an abutting portion 17 projecting inward so as to abut the side surface of the tool T on the tip side. The contact portion 17 prevents the tool T from unintentionally dropping from the tool holder 8 by contacting the tool T obliquely rearward as viewed from the holder body 13. Further, the abutting portion 17 is formed by, for example, a rotatable roller so that when the tool holder 8 holds the tool T, the abutting portion 17 moves along the side surface of the tool T to smoothly swing the arm 14 outward. Can be formed.

  The positional deviation detection device 12 includes a rotation detection unit 18 that detects the rotation of the spindle 3, and a tool magazine based on the amount of rotation of the spindle detected by the rotation detection unit 18 when the tool T is transferred from the spindle 3 to the tool holder 8. And a determination unit 19 for determining the positional deviation of 10.

  The rotation detection unit 18 is configured by a sensor such as a rotary encoder that detects the rotation amount of the main shaft 3. When a sensor or the like for detecting the amount of rotation of the spindle 3 is provided for another purpose, this sensor or the like can also be used as the rotation detection unit 18. Specifically, since a spindle encoder provided in a general machine tool can also be used as the rotation detector 18, the design around the spindle of the machine tool 1 can be the same as that of an existing machine tool.

  After the positioning of the tool magazine 10 is completed, the determination unit 19 confirms the rotation amount of the spindle 3 after the transfer of the tool T is started, and when the maximum rotation amount is equal to or greater than a preset threshold value, the tool magazine It is determined that 10 is rotationally displaced. Further, when the maximum rotation amount is equal to or greater than the threshold value, the determination unit 19 determines the displacement direction of the tool magazine 10 from the rotation direction when the rotation amount of the spindle 3 is maximum.

  The rotational displacement of the tool magazine 10 and the rotation of the spindle 3 when the tool T is delivered are caused by the friction between the contact portion 17 of the tool holder 8 and the tool T. Therefore, for example, the relationship between the rotational displacement of the tool magazine 10 and the rotational amount of the spindle 3 varies due to differences in conditions such as the speed at which the contact portion 17 moves along the side surface of the tool T and the dirt on the surface of the tool T. .. Therefore, the threshold value of the maximum rotation amount preset in the determination unit 19 may be empirically determined in consideration of the actual rotation amount of the spindle 3 under different conditions.

  It is considered difficult to accurately specify the amount of displacement of the tool holder 8 by the displacement detection device 12. Therefore, the threshold of the maximum rotation amount does not correspond to the permissible amount of rotational displacement of the tool magazine 10, but a range in which significant determination is possible so that the rotational displacement of the tool magazine 10 can be kept as small as possible. It is preferable to set it to a relatively small value. Since the positional deviation detecting device 12 can detect the rotational positional deviation of the tool magazine 10 by the tool T exchanging operation in the normal work machining of the machine tool 1, the rotational positional deviation of the tool magazine 10 between the exchanging of the tool T. Can be corrected. Therefore, it is considered that even if the positional deviation detecting device 12 frequently detects the rotational positional deviation of the tool magazine 10, the machining of the work by the machine tool 1 is not limited.

  The determination unit 19 can be configured by, for example, a computer or the like, and is integrated with the main control device 7 or another control device (for example, a servo control device that is independently placed to control the servo motor 11 of the tool magazine 10). You may comprise. Specifically, the determination unit 19 can be realized by incorporating a sub-program or the like for determining the rotational displacement of the tool magazine 10 into a processing program executed by a computer that constitutes the main control device or another control device. .

  The tool exchanging device 2 preferably performs control to correct the origin position of the servo motor 11 of the tool magazine 10 when the position displacement detecting device 12 determines that the tool magazine 10 is rotationally displaced. This origin correction control can be performed by the main controller 7. In addition, when it is determined that the tool magazine 10 is out of rotational position, the tool changing device 2 may issue an alarm notifying the operator of that fact.

  The origin correction control can be a control that moves the origin position of the servo motor 11 in a direction that cancels the rotational position deviation of the tool magazine 10 detected by the position deviation detection device 12 by a predetermined minute amount of origin movement. The amount of movement of the origin in the origin correction control is close to the amount of displacement of the rotational position of the tool magazine 10 corresponding to the threshold value of the maximum amount of rotation of the spindle 3 preset in the determination unit 19 (for example, the rotational angle of the tool magazine 10 is 0. It is suitable to set it to about 1 °.

  In such origin correction control, there is a possibility that the rotational position deviation of the tool magazine 10 cannot be completely eliminated by correcting the origin position once, but the rotational position deviation of the tool magazine 10 will be changed when the next tool T is replaced. When is detected again, the same origin correction control is repeatedly performed, so that the rotational displacement of the tool magazine 10 can be finally reduced below the threshold value.

  Next, with reference to FIG. 5, a procedure of processing for detecting the positional deviation of the tool magazine 10 by the positional deviation detection device 12 in the machine tool 1 will be described. This process is performed when the tool T held by the spindle 3 is transferred to the tool holder 8.

  First, in step S1, the tool magazine 10 is rotationally positioned so that the tool holder 8 which should receive the tool T faces the spindle 3, and the key groove K of the tool T mounted on the spindle 3 is positioned at the correct position. The rotational position of the spindle 3 is determined so as to directly face the tool magazine 10 (orientation).

  Subsequently, in step S2, the operation of transferring the tool T from the spindle 3 to the tool holder 8 is started. Specifically, the tool holder 8 is moved to the spindle 3 side, the tool T is sandwiched by the pair of arms 14, and the spindle head 6 is lifted to start a series of operations for detaching the tool T from the spindle 3. The tool holder 8 may be moved by swinging the tool magazine 10. In this case, since the tool holder 8 also moves in the vertical direction, the spindle head 6 may be moved up and down accordingly to cancel the vertical movement of the tool holder 8.

  In the next step S3, the rotation of the spindle 3 that accompanies the transfer operation of the tool T started in step S2, that is, the change in the angular position of the spindle 3 with time is recorded.

  When the tool magazine 10 is displaced, when the tool holder 8 is advanced toward the tool T for the delivery of the tool T, one of the pair of arms 14 first comes into contact with the tool T and the friction force is increased. The tool T and thus the main shaft 3 are slightly rotated by. The amount of rotation of the main shaft 3 due to friction with the arm 14 increases as the amount of displacement of the tool magazine 10 increases, although there are variations. The direction of rotation of the main shaft 3 due to friction with the arm 14 is opposite to the direction of displacement of the tool magazine 10.

  When the tool holder 8 is further advanced, the key 16 is fitted into the key groove K of the tool T, and the angle of the tool T is corrected so as to face the tool holder 8. In the process in which the key 16 of the tool holder 8 is fitted, the tool T and the spindle 3 can rotate by overshooting in the direction opposite to the direction of rotation due to friction with the arm 14. However, when the tool magazine 10 is displaced to such an extent that the maximum rotation amount of the spindle 3 becomes equal to or greater than the threshold value, the amount of rotation of the spindle 3 in the opposite direction when the key 16 is fitted is the amount of rotation due to friction with the arm 14. Will never be bigger than

  In the next step S4, it is confirmed whether or not the transfer operation of the tool T is completed. If the transfer operation of the tool T is not completed, the successive change of the angular position of the spindle 3 in step S3 is continued, If the delivery operation is completed, the process proceeds to the next step S5.

  In step S5, the maximum absolute value of the angular position of the spindle 3, that is, the maximum amount of rotation of the spindle 3 from the origin, is extracted in the successive change of the angular position of the spindle 3 recorded in step S3.

  In the next step S6, the maximum rotation amount of the spindle 3 from the origin is compared with a preset threshold value. If the maximum rotation amount of the spindle 3 is equal to or more than the threshold value, the rotation direction of the spindle 3 is determined in step S7, the tool magazine 10 is displaced in step S8, and the position is output after the direction is output. The shift detection process ends. On the other hand, when the maximum rotation amount of the spindle 3 is less than the threshold value, the positional deviation detection process is immediately ended.

  In step S7, the misalignment direction of the tool magazine 10 is determined depending on whether the maximum rotation amount of the spindle 3 is a positive value or a negative value. As described above, the direction of displacement of the tool magazine 10 is opposite to the direction of rotation of the main spindle 3 due to friction with the arm 14 that causes the maximum amount of rotation of the main spindle 3.

  In step S8, the misalignment of the tool magazine 10 and the direction of the misalignment are transmitted from the misregistration detection device 12 to a component that performs control for correcting the origin of the servomotor 11. When the determination unit 19 of the positional deviation detection device 12 and the component that performs control for correcting the origin of the servo motor 11 are configured by the same computer, for example, the program that configures the determination unit 19 stores a predetermined bit in the memory. By rewriting, the program for correcting the origin of the servomotor 11 performs processing such as recognizing the occurrence of the positional deviation and the direction of the positional deviation.

  As described above, the machine tool 1 including the tool exchanging device 2 having the positional deviation detecting device 12 detects the position of the tool magazine 10 by the movement of the spindle 3 when the tool T is delivered without confirming the movement of the tool magazine 10. Since the deviation can be detected, the positional deviation of the tool magazine 10 is detected while the tool is being changed during the machining of the work piece in the normal procedure, and the tool magazine is parallel to the machining of the work by the next tool exchange. It is possible to correct the positional deviation of 10.

  Further, since the positional deviation detection device 12 detects the positional deviation of the tool magazine 10 based on the rotation amount of the spindle 3 during the operation of transferring the tool T from the spindle 3 to the tool holder 8, a plurality of tool magazines 10 are finally detected. Even if the tool is placed with an unbalanced weight, the determination result is not affected, and the positional deviation of the tool magazine 10 can be reliably detected.

  Since the rotation detection unit 18 and the determination unit 19 of the positional deviation detection device 12 can be realized by using a spindle encoder and a control device of a general machine tool, the machine tool 1 uses an existing machine tool and is mechanical. It can be implemented only by changing the control program without changing the design.

  Although the embodiment of the invention has been described above, the invention is not limited to the embodiment described above. In addition, the effects described in the present embodiment are merely enumeration of the most suitable effects resulting from the present invention, and the effects according to the present invention are not limited to those described in the present embodiment.

  Since the tool changer according to the present invention does not need to detect the movement of the tool magazine in order to detect the displacement of the tool magazine, it does not have a drive motor dedicated to the tool magazine (for example, drive for other components). It is also applicable to the case where the tool magazine is connected to the power source via a clutch to drive the tool magazine, and the like, and the positional deviation of the tool magazine can be detected.

1 Machine Tool 2 Tool Changer 3 Spindle 4 Table 5 Spindle Guide 6 Spindle Head 7 Main Controller 8 Tool Holder 9 Magazine Main Body 10 Tool Magazine 11 Servo Motor 12 Displacement Detection 13 Holder Main Body 14 Arm 15 Spring 16 Key 17 Abutting Part 18 Rotation Detection Section 19 Judgment Section K Keyway T Tool

Claims (3)

A tool having a plurality of tool holders arranged in an annular shape, each holding a tool attachable to a spindle of a machine tool, and rotating so as to transfer the tool between the spindle and any of the tool holders A magazine,
A positional deviation detection device for detecting rotational positional deviation of the tool magazine with respect to the spindle,
Equipped with
The tool holder is
A body proximate to the side of the tool,
A pair of arms extending from the main body, urged to sandwich the tool, and provided with an abutting portion projecting inward so as to abut on a side surface of the tool on a tip side,
The displacement detection device,
A rotation detection unit that detects the rotation of the main shaft,
A determination unit that determines the positional deviation of the tool magazine based on the rotation amount of the spindle detected by the rotation detection unit when transferring the tool from the spindle to the tool holder,
A tool changer characterized by having.   The determination unit determines that the tool magazine is displaced in rotational position when the maximum rotation amount of the spindle when delivering the tool is equal to or greater than a preset threshold value, and the rotation amount of the spindle is maximum. The tool exchanging device according to claim 1, wherein a direction in which the tool magazine is displaced is determined based on a rotation direction when it becomes. A tool changer according to claim 1 or 2,
A spindle on which a tool can be mounted by the tool changing device,
A machine tool equipped with.

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