Pallet exchanger of work machine

Abstract

To provide a pallet exchanger that suppresses or prevents accumulation of cutting chips in an APC arm.SOLUTION: A pallet exchanger 44 of a machine tool 10 includes: an APC arm 50 configured to be turnable by an APC arm drive mechanism 56 in order to exchange pallets 76, 94 in between a preparation chamber 14 and a processing chamber 12; an engagement pin 54a arranged in the APC arm 50; a turn door 46 arranged in the upper side of the APC arm 50 so as to partition the preparation chamber 14 and the processing chamber 12, having a guide hole 46a for engagement with the engagement pin 54a, and being turnable together with the APC arm 50 when the engagement pin 54a and the guide hole 46a engage with each other; and a cutting chip cover 52 attached to the turn door 46 and covering the upper side of the APC arm 50 when a longitudinal direction of the APC arm 50 is arranged along a width direction of the turn door 46 when viewing the processing chamber 12 side from the preparation chamber 14 side.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a pallet changer for a machine tool. [Background technology]

[0002] A wide variety of pallet exchange devices have been disclosed for loading and unloading pallets containing workpieces into and from machine tools, with different methods for loading and unloading pallets depending on the application. For example, Patent Document 1 discloses a pallet exchange device for a five-axis machine tool with three linear axes and two rotary axes, equipped with a swivel arm that can move in the direction of carriage movement and is supported to rotate together with the swivel axis. Patent Document 2 also discloses a pallet exchange device equipped with an exchange means (arm) with claws for gripping the pallet, a rotary drive means for rotating the exchange means about a vertical axis, and an elevating means for raising and lowering the exchange means. However, these arms are always exposed to the machine tool and table, even when the machine is in standby mode and not changing pallets. This makes them prone to accumulation of chips generated during machining. Furthermore, these pallet exchange devices have a complex structure and require a large amount of space within the machine tool. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Utility Model Registration No. 2604055 [Patent Document 2] Patent No. 6427309 Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above circumstances, an object of the present invention is to provide a pallet changing device that suppresses or prevents chips from accumulating on an APC arm. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a pallet exchange device for a machine tool comprising: a rotating arm on both sides of which pallets can be placed, the rotating arm being configured to be rotatable by a rotating mechanism in order to exchange pallets between a setup chamber and a machining chamber; an engaging portion arranged on the rotating arm; a rotating door arranged above the rotating arm to separate the setup chamber and the machining chamber, the rotating door having an engaged portion for engaging with the engaging portion, the rotating door being rotatable together with the rotating arm when the engaged portion and the engaging portion are engaged; and a chip cover attached to the rotating door, which covers the upper side of the rotating arm when the longitudinal direction of the rotating arm is positioned along the width direction of the rotating door when viewed from the setup chamber side to the machining chamber side. [Effects of the Invention]

[0006] According to one aspect of the present invention, a pallet changer for a machine tool includes a swivel arm configured to be swiveled by a swivel mechanism for changing pallets, a swivel door arranged above the swivel arm and swiveling together with the swivel arm by engaging an engaging portion arranged on the swivel arm with an engaging portion, and a chip cover attached to the swivel door that covers the upper side of the swivel arm when the longitudinal direction of the swivel arm is aligned with the width direction of the swivel door as viewed from the setup chamber to the machining chamber. Therefore, when the swivel arm is arranged so that both sides on which the pallet can be placed are not exposed from the lower side of the swivel door to change pallets between the setup chamber and the machining chamber, i.e., when the swivel arm is aligned with the width direction of the swivel door, it is possible to prevent or suppress chips from accumulating on the swivel arm covered by the chip cover. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 shows a plan view of a machine tool equipped with a pallet exchange device according to this embodiment. [Figure 2] FIG. 2 is a perspective view of the APC arm according to this embodiment. [Figure 3]FIG. 3 shows a perspective view of the APC arm stored in the pivot door. [Figure 4] FIG. 4 shows a perspective view of the APC arm rotated 90 degrees to transfer the pallet. [Figure 5] FIG. 5 shows a perspective view of the APC arm pivoting 180 degrees to exchange pallets. [Figure 6] Figure 6 shows the three height positions of the APC arm as seen from the setup room side. DETAILED DESCRIPTION OF THE INVENTION

[0008] The pallet exchange device according to the embodiment will be described below with reference to the accompanying drawings. Similar or corresponding elements are designated by the same reference numerals, and duplicated explanations will be omitted. For ease of understanding, the scale of the drawings may be changed.

[0009] FIG. 1 shows a schematic plan view of a machine tool 10 equipped with a pallet changer 44 according to this embodiment. The machine tool 10 is covered by a splash guard 16 to prevent chips generated during machining from scattering, etc. The interior of the splash guard 16 is divided into a machining chamber 12 and a setup chamber 14 by a pivot door 46 that is arranged to be rotatable (pivotable) about a pivot axis RA2 (see FIG. 5) that is parallel to the vertical direction. An operator door 12a and a setup chamber door 14a are attached to the splash guard 16 so that an operator (not shown) can access the interior of the machining chamber 12 and the setup chamber 14 from the outside. The setup chamber 14 side of the machine tool 10 is the front of the machine.

[0010] Here, the splash guard 16 is described as being configured to cover both the machining chamber 12 and the setup chamber 14, but this is not limiting. The splash guard may cover only the machining chamber. Even if the splash guard is configured to cover only the machining chamber, it can prevent chips generated during machining from scattering.

[0011] Within the machining chamber 12, devices such as a spindle 26 and a C-axis rotary table 36 are arranged for machining workpieces W1 and W2 (see FIG. 5) as workpieces. In the machine tool 10, a pair of X-axis linear guides 30 are arranged on the upper surface of a bed 18, which is placed on the floor of a factory or the like where the machine is installed. The X-axis linear guides extend in the left-right direction as viewed from the front of the machine, i.e., along the X-axis. A column 22 is arranged upright on the X-axis linear guides 30, allowing it to move back and forth along the X-axis linear guides. The machine tool 10 also has a pair of Y-axis linear guides (not shown) extending vertically (along the Y-axis, perpendicular to the plane of FIG. 1) in front of the column 22. A saddle 24 is arranged on the Y-axis linear guides, allowing it to move back and forth along the Y-axis linear guides. A spindle 26, rotatable about a horizontal central axis, is arranged in front of the saddle 24. A tool 28 for machining the workpieces W1 and W2 is detachably attached to the front side of the spindle 26 (toward the setup room 14). Machine tool 10 is electrically connected to spindle 26, has an NC device (not shown) for controlling machining, and is configured to be able to control machining of workpieces W1, W2 using tool 28. It should be noted that the shapes of workpieces W1, W2 shown in Figure 5 are the maximum workpiece shapes envisioned by the inventors in their design, and are shown for reference only.

[0012] A pair of Z-axis linear guides 38 are provided on the upper surface of the bed 18 in front of the spindle 26 of the machine tool 10, extending in the front-to-rear direction, i.e., along the Z-axis direction. A Z-axis table 32 is disposed on the Z-axis linear guides 38, allowing it to reciprocate along the Z-axis linear guides 38. A B-axis rotary table 34 is disposed on the Z-axis table 32, and is rotatable about a rotation axis (about the B-axis) parallel to the vertical direction. A C-axis rotary table 36 is disposed on the B-axis rotary table 34, and is configured as a table configured so that the top surface 76a (see FIG. 2) of a mounted pallet 76 (first pallet) is positioned upright on the vertical plane. The C-axis rotary table 36 also has a pallet holding mechanism (not shown), such as a locating pin, for holding the pallet 76, and is configured to rotate the mounted workpiece W1 and pallet 76 about a horizontal central axis (about the C-axis). In this way, the workpieces W1 and W2 can be aligned with the tool 28 using the Z-axis table 32, the B-axis rotary table 34, and the C-axis rotary table 36. Furthermore, the machine tool 10 includes an X-axis feeder for driving the column 22 along the X-axis linear guide 30, a Y-axis feeder for driving the saddle 24 along the Y-axis linear guide, and a Z-axis feeder for driving the Z-axis table 32 along the Z-axis linear guide 38 (all of which are not shown). These components configure the machine tool 10 as a five-axis controlled machine tool having three linear axes, the X-axis, the Y-axis, and the Z-axis, and two rotary axes, the B-axis and the C-axis. Note that this is merely one example, and the five-axis controlled machine tool may also have a combination of three linear axes plus a combination of rotary axes, the A-axis and the B-axis, or the A-axis and the C-axis. Alternatively, the five-axis controlled machine tool may be a four-axis controlled machine tool with only one rotary axis, or a six-axis controlled machine tool with all of the A-axis, B-axis, and C-axis. Furthermore, the machine tool 10 is structured so that the spindle 26 side has an X-axis and a Y-axis, and the workpiece W1 side has a Z-axis, a B-axis, and a C-axis, but the linear axes and rotary axes may be arranged in any manner on the spindle side and the workpiece side.

[0013] A setup station 40 is disposed within the setup chamber 14 for performing setup such as attaching (assembling) the workpiece W1 before machining to the pallet 76 and removing the workpiece W2 after machining. The setup station 40 is equipped with a pallet position changing device 42 for changing the position of the workpiece W1 attached to the pallet 76. The setup station 40 also has a medium supply unit 80 for supplying a medium including oil, air, and cutting fluid to the pallet 76 and either the workpiece W1 and / or the jig attached to the pallet 76. The medium supply unit 80 is configured to supply the medium via a coupler (not shown) attached to the underside 76b of the pallet 76 (see FIG. 2).

[0014] As will be described later, the revolving door 46 separating the machining chamber 12 and the setup chamber 14 is loaded on the APC arm 50 when the height position of the APC arm 50 serving as a revolving arm is between the second height position H2 and the third height position H3. When the APC arm 50 is disengaged from the revolving door 46 during replacement of the pallet 76 and the APC arm 50 is lowered to the first height position H1, the revolving door 46 is placed on a revolving door holder 48 disposed below the side wall of the splash guard 16. Specifically, the revolving door 46 is placed in a state in which mating portions (not shown) formed on both the revolving door 46 and the revolving door holder 48 are mated with each other. The width direction of the revolving door 46 is the left-right direction when viewed from the front of the machine, i.e., the X-axis direction. A pallet exchanger 44 is disposed below the pivoting door 46, either separately from the pivoting door 46 or in conjunction with the pivoting door 46, and is configured to be rotatable about a pivot axis RA2 parallel to the vertical direction (Y-axis direction). The pallet exchanger 44 includes an APC arm 50 that operates as a pivoting arm rotatably disposed about the pivot axis RA2 parallel to the vertical direction (Y-axis direction) to transfer an unmachined workpiece W1 and a machined workpiece W2 between the setup chamber 14 and the machining chamber 12, and an APC arm drive mechanism 56 as a pivoting mechanism for pivoting the APC arm 50. The APC arm 50 is configured to be movable up and down in the vertical direction (Y1 direction in FIG. 2 ) by the APC arm drive mechanism 56. The APC arm drive mechanism 56 has an actuator (not shown) such as a hydraulic cylinder, a pneumatic cylinder, or a servo motor that enables fine operation setting and adjustment, and the actuator pivots and moves the APC arm 50 up and down. The actuator is configured to be controllable by a control device (not shown) arranged in the machine tool 10. Here, "APC" is an abbreviation for "Automatic Pallet Change." While the rotating door holder 48 has been described as being arranged on the lower side of the side wall of the splash guard 16, the present invention is not limited to this, and the rotating door holder may be installed directly on the bed or floor surface.Furthermore, the pivoting door holding portion may hold the pivoting door in a manner other than the mating portion, as long as it can regulate the rotational and gravitational movement of the pivoting door in place of the APC arm when the APC arm has descended to the first height position H1 and is not engaged with the pivoting door.

[0015] As shown in FIG. 6 , the APC arm 50 has three height positions. Here, the three height positions are defined as a first height position H1, a second height position H2, and a third height position H3, in order from the bottom up. The first height position H1 is a height position at which the APC arm 50 can swing independently without interfering with the swing door 46 due to protruding portions such as the pallet holders 82 and 84 ( FIG. 2 ). Therefore, the engagement between the APC arm 50 and the swing door 46 is released, and the swing door 46 is placed on the swing door holder 48. The second height position H2 is a height position at which the workpieces W1 and W2 are placed on hold for machining. Therefore, the swing door 46 is placed on the swing door holder 48, and the APC arm 50 is in contact with or in close contact with the swing door 46. At this time, the protruding portions such as the pallet holders 82 and 84 are accommodated in a space (not shown) formed on the lower end of the swing door 46. The third height position H3 is a height position when the swing door 46 swings together with the pallets 76, 94 loaded thereon in order to exchange the pallets 76, 94. When the APC arm 50 is not transferring workpieces, such as when the APC arm 50 is waiting for the machine tool 10 to machine the workpieces W1, W2, it is positioned as a storage position with its longitudinal direction aligned with the width direction of the swing door 46, i.e., the X-axis direction. At this time, the APC arm 50 is moved to the second height position H2 so that the APC arm 50 is in close contact with or abuts the swing door 46 without creating a gap between them, and is stored in a state engaged with the lower end of the swing door 46. A chip cover 52 (see FIG. 3 ) is formed on the lower side of the swing door 46, having an inclined surface that extends downward (vertically downward) toward the setup station 40 and the machining chamber 12 (front and rear in the Z-axis direction). The chip cover 52 is formed to cover from above the APC arm 50 engaged with the swing door 46, and can prevent or suppress chips and the like generated by machining in the machining chamber 12 from adhering to the APC arm 50. When changing a pallet, the APC arm 50 moves to a third height position H3 and is positioned so that its longitudinal direction is perpendicular to the width direction of the swing door 46, i.e., along the Z-axis direction.

[0016] Here, the chip cover 52 is described as being formed on the lower side of the pivoting door 46, but this is not limiting. The chip cover may be formed, for example, from the upper side of the pivoting door over the entirety, or may be formed separately from the pivoting door. Furthermore, the chip cover only needs to be able to cover the APC arm, and its outer periphery may be formed, for example, in the shape of a quarter sphere rather than an inclined surface.

[0017] As shown in FIG. 2 , the APC arm 50 is provided with a first pallet holder 82 and a second pallet holder 84 at both ends in the longitudinal direction thereof for holding a pallet 76. The first pallet holder 82 and the second pallet holder 84 each have a column-shaped member at both ends in the width direction of the APC arm 50, and are concave-shaped when viewed in the longitudinal direction of the APC arm 50. A holding member 76f is attached to the abutment side surface 76d of the pallet 76, which is the side surface facing the APC arm 50. The holding member 76f is formed in a plate shape with dimensions that allow it to fit into the concave portions of the first pallet holder 82 and the second pallet holder 84. Therefore, when the pallet 76 is in an upright position, the holding member 76f fits into the concave portions of the first pallet holder 82 and the second pallet holder 84, and the upper surfaces of the column-shaped members at both ends of the first pallet holder 82 and the second pallet holder 84 abut against the abutment side surface 76d of the pallet 76. This allows the APC arm 50 to support the pallet 76 and hold the upright pallet 76, a jig (not shown) attached thereto, and the workpiece W1.

[0018] It is noted that, although it has been described herein that the first pallet holding unit 82 and the second pallet holding unit 84 of the APC arm 50 support the pallet 76 by fitting the holding members 76f into the concave portions and abutting the upper surfaces of the columnar members at both ends against the abutting side surfaces 76d of the pallet 76, this is not limitative. For example, the holding units of the APC arm may be configured with a mechanism that clamps the upper and lower surfaces of the pallet, or a holding member other than a plate shape may be fitted and inserted into a portion having a shape other than a concave shape (for example, a wedge shape).

[0019] As shown in FIG. 1 , the APC arm 50 and the swing door 46 can be engaged with each other by an engagement mechanism 54. The engagement mechanism 54 includes an engagement pin 54a serving as an engaging portion on the APC arm 50 side and a guide hole 46a serving as an engaged portion on the swing door 46 side. The engagement pin 54a is formed on the upper surface of the APC arm 50 and extends upward. Therefore, the engagement pin 54a moves up and down in accordance with the up and down movement of the APC arm 50. The guide hole 46a is formed in the bottom of the swing door 46 so as to be able to engage with the inserted engagement pin 54a. Here, two engagement pins 54a are arranged at equal intervals of 180° around the rotation axis RA2 of the APC arm 50, and four guide holes 46a are formed at equal intervals of 90° around the rotation axis RA2 of the APC arm 50 to correspond to the engagement pins 54a. Note that at least one pair of engagement pins 54a and guide holes 46a is required. The engagement mechanism 54 is configured so that the engagement pin 54a and the guide hole 46a can be engaged or disengaged, thereby engaging the APC arm 50 and the pivoting door 46. Therefore, when the APC arm 50 and the pivoting door 46 are engaged, the APC arm 50 and the pivoting door 46 can be pivoted together. Furthermore, when the APC arm 50 and the pivoting door 46 are disengaged, the APC arm 50 can be pivoted independently to transfer a pallet 76, 94 to the APC arm 50 or to store the APC arm 50 in a storage position when not transferring a pallet. Note that, in this description, the APC arm 50 has the engagement pin 54a and the pivoting door 46 has a guide hole 46a formed in its bottom. However, this is not limiting. For example, the pivoting door may have an engagement pin extending from its bottom, or a guide hole may be formed in the APC arm. In addition to the combination of the engagement pin 54a and the guide hole 46a, the engagement pin may be configured to engage / disengage with claws or the like disposed on both the APC arm and the swing door. Furthermore, the engagement pin is not limited to being rod-shaped or column-shaped, and may be configured to be movable up and down using, for example, a drive mechanism disposed in the engagement mechanism.

[0020] Specifically, the pallet exchange device 44 operates as follows. When the transfer of a pallet 76 begins in the machine tool 10, the APC arm drive mechanism 56 lowers the APC arm 50, which is in the storage position, from the second height position H2 to the first height position H1. At this time, the engagement pin 54a of the engagement mechanism 54 disengages from the guide hole 46a, thereby disengaging the APC arm 50 from the APC arm 50, and the swing door 46 is fitted into and placed on the swing door holder 48. When the APC arm 50 descends to the first height position H1, the APC arm drive mechanism 56 swings the APC arm 50 by 90 degrees (or 270 degrees) (see FIG. 4). As a result, the first pallet holding unit 82 and the second pallet holding unit 84 of the APC arm 50 move along the rotation trajectory TR1 toward the C-axis rotary table 36 and the pallet position changing device 42 (move to the pallet exchange position), and the longitudinal direction of the APC arm 50 becomes aligned with the Z-axis direction (perpendicular to the width direction of the swing door 46). In addition, to transfer the pallets 76, 94, the C-axis rotary table 36 moves toward the APC arm 50, and the pallet position changing device 42 rotates the arm 64 to an upright position while holding the pallet 76.

[0021] When the first pallet holder 82 and the second pallet holder 84 move toward the C-axis rotary table 36 and the pallet attitude changing device 42, the APC arm drive mechanism 56 raises the APC arm 50 to the second height position H2. As the APC arm 50 rises to the second height position H2, the engagement pin 54a of the engagement mechanism 54 is inserted into and engaged with the guide hole 46a. This engages the revolving door 46 with the APC arm 50, and the revolving door 46 is loaded onto the APC arm 50 instead of the revolving door holder 48.

[0022] Once the APC arm 50 has loaded the swing door 46, the APC arm drive mechanism 56 raises the swing door 46 and the APC arm 50 to the third height position H3. This allows the holding members 76f of the pallet 76 to fit into the recessed portions of the first pallet holder 82 and the second pallet holder 84, and the columnar members at both ends to abut against the abutment side surfaces 76d of the pallet 76, thereby holding the pallet 76. At this point, the C-axis rotary table 36 releases the pallet holding mechanism, and the pallet position changing device 42 releases its hold on the pallet using the fingers 72 (see FIG. 2), and the pallet 76 is delivered to the APC arm 50. After delivering the pallet 76 to the APC arm 50 at the pallet delivery position, the C-axis rotary table 36 and / or the pallet position changing device 42 retract to a retracted position where they do not interfere with the swinging APC arm 50 or swing door 46. Subsequently, the APC arm 50 rotates them integrally by 180 degrees (see FIG. 5). This allows the pallet 76 held by the APC arm 50 to be swapped between the machining chamber 12 side and the setup chamber 14 side. Once the pallet 76 has been swapped, the C-axis rotary table 36 and / or the arm 64 of the pallet position changing device 42 move from the retracted position to the pallet transfer position, and the swapped pallet 76, 94 is held by the pallet holding mechanism of the C-axis rotary table 36 and / or the finger 72 of the pallet position changing device 42. Furthermore, the APC arm drive mechanism 56 lowers the swing door 46 and the APC arm 50 holding the pallet 76 to the second height position H2 (see FIG. 5). The swing door 46, which was previously held only by the APC arm 50, is then placed in a state where it is fitted into the swing door holder 48. Furthermore, engagement pin 54a of engagement mechanism 54 is pulled out of guide hole 46a, and engagement is released. APC arm drive mechanism 56 lowers APC arm 50 to first height position H1, and then rotates 90 degrees to move first pallet holder 82 and second pallet holder 84 below pivot door 46.

[0023] When the first pallet holder 82 and the second pallet holder 84 move below the swing door 46, the APC arm drive mechanism 56 raises the APC arm 50 to the second height position H2, and the swing door 46 is placed on the APC arm 50 instead of the swing door holder 48. Furthermore, the engagement pin 54a of the engagement mechanism 54 is inserted into the guide hole 46a, and they engage with each other. This causes the APC arm 50 to be stored in the storage position below the swing door 46 (see FIG. 3).

[0024] As shown in FIG. 2, the setup station 40 is provided with a pallet position changing device 42 for transferring a pallet 76, on which a pre-machined workpiece W1 and a machined workpiece W2 have been mounted, to and from the APC arm 50. The pallet 76 is formed in a plate shape having an upper surface 76a on which the workpiece W1 and a jig (not shown) are mounted, and a lower surface 76b. The pallet 76 also has two engaging side surfaces 76e that are in contact with the upper surface 76a and the lower surface 76b and are located on the outer side of the pallet 76 in the X-axis direction, an abutting side surface 76d that is located between the two engaging side surfaces 76e, is located on the rear side of the pallet 76 in the Z-axis direction, and faces the APC arm 50, and a front side surface 76c that is located on the front side of the pallet 76 in the Z-axis direction and faces the setup chamber door 14a. The two engaging side surfaces 76e are formed integrally with the pallet 76 and have pins 78 that extend outward, i.e., outward in the X-axis direction. Here, two cylindrical pins 78 extending along the surface direction of the engagement side surface 76e are formed on each engagement side surface 76e. The two pins 78 are formed at an interval, one on each end side of the engagement side surface 76e in the longitudinal direction (Z-axis direction). Note that one pin may be formed on each engagement side surface, and the pins may be formed in a shape other than a cylindrical shape, such as a rectangular prism or a triangular prism.

[0025] An operator who places a pallet 76 in the setup station 40 of the setup room 14 and assembles a workpiece and a jig on the pallet 76 places the pallet 76 on the medium supply unit 80 in a horizontal position with the upper surface 76a of the pallet 76 facing the horizontal plane. Therefore, in order to transfer the pallet 76 between the setup station 40 and the C-axis rotary table 36 to which the pallet 76 is attached in an upright position, the pallet position changing device 42 is configured to hold the pallet 76 and change its position, including between a horizontal position and an upright position. Specifically, the pallet position changing device 42 includes a base 60 disposed along the X-axis direction and forward of the swing door 46 and the APC arm 50 in the Z-axis direction; a drive unit 62 attached to the base 60 and configured so that its rotation axis extending along the X-axis (horizontal direction) can rotate around a rotation center axis RA1 (in the R1 direction); and a pair of arms 64 rotatably attached to the drive unit 62, extending parallel to the two engagement side surfaces 76e when facing them and capable of holding the pallet 76. The base 60 extends from the outer periphery of the APC arm drive mechanism 56 disposed at the position of the rotation axis RA2 of the APC arm 50 toward the front side in the Z axis direction (toward the preparation chamber door 14a).

[0026] The drive unit 62 has an actuator (not shown) such as a hydraulic cylinder, a pneumatic cylinder, or a servo motor that allows for fine operation setting and adjustment, and the actuator rotates the rotary shaft. The actuator is configured to be controllable by a control device (not shown) arranged in the machine tool 10. Furthermore, the pallet position changing device 42 is configured to be able to position (stop) the arm 64 not only between the upright position and the horizontal position, but also by rotating and positioning the arm 64 from the upright position in the upright position to a retracted position beyond the engagement position in the horizontal position. The pallet position changing device 42 is also configured to be able to position (stop) at an intermediate position, such as a standby position between the upright position and the engagement position.

[0027] In the following description, the pallet 76 is assumed to be square in plan view, with two parallel engagement sides 76e held by a pair of parallel arms 64; however, this is not limiting. For example, the pallet may have chamfered corners or may have a shape other than a square, such as an octagonal or round shape in plan view. Furthermore, even if the pallet has a shape other than a square and the two engagement sides are not parallel, the pair of arms may not be parallel to each other, for example, extending in a V-shape in plan view so as to be parallel to the two engagement sides. If the pallet is round, the arms may be curved to fit the outer shape of the pallet.

[0028] The arm 64 has an arm base end 66 that is connected to the rotation shaft of the drive unit 62, and an arm engaging unit 68 that extends linearly from an outer portion of the arm base end 66 in the X-axis direction so as to face the engaging side surface 76e. A receiving portion 74 is formed on the inner side in the X-axis direction of the arm base end 66, which is on the base 60 side of the arm 64, at a position that faces the abutting side surface 76d when the arm 64 holds a pallet 76. The receiving portion 74 is formed in an L-shape or an inverted L-shape when viewed from the side of the machine tool 10 (outside in the X-axis direction) in a horizontal state, and has a planar first pallet receiving surface 74a that extends perpendicular to the arm 64 and a planar second pallet receiving surface 74b that extends along the longitudinal direction of the arm 64, and is sized so that the abutting side surface 76d can abut against the first pallet receiving surface 74a and the underside 76b can abut against the second pallet receiving surface 74b. The first and second pallet receiving surfaces do not need to be precisely sized, but only need to be formed to a degree that allows them to abut against the pallet and reliably support the weight of the pallet. For this reason, the first and second pallet receiving surfaces are not limited to flat surfaces, and may be formed, for example, in a curved or polygonal pyramidal shape, which may support the pallet in point or line contact.

[0029] Each arm 64 is provided with two slides 70, which are located at both longitudinal ends of the arm engagement portion 68, i.e., both ends in the Z-axis direction, and are configured to slide along the longitudinal direction of the arm engagement portion 68. Furthermore, a finger 72 for engaging with a pallet 76 is attached to each of the two slides 70. The spacing between the two fingers 72 is configured to correspond to the spacing between the two pins 78. A rod disposed within the arm engagement portion 68 is integrally connected to the two slides 70, and the rod is connected to an actuator such as a hydraulic cylinder, a pneumatic cylinder, or a servo motor that allows for fine operation setting and adjustment (all not shown). Therefore, in response to the operation of the rod by the actuator, the slides 70 and the fingers 72 can be moved in the same direction between a pallet engagement position and a pallet disengagement position. Here, the pallet engagement position is configured to be closer to the arm base end 66 than the pallet disengagement position. Furthermore, the actuators that operate the slides 70 and the fingers 72 are configured to be controllable by a control device (not shown) disposed in the machine tool 10. When viewed from the longitudinal direction of the arm 64, the fingers 72 are formed in a concave shape facing the pallet 76. The fingers 72 are formed so that their depth dimension, i.e., their dimension in the X-axis direction, matches the dimension in the extension direction of the pins 78, i.e., their dimension in the X-axis direction. Therefore, the arm engagement portion 68 can be moved laterally toward the engagement side surface 76e of the pallet 76 and moved (slid) from a position where the fingers 72 and the pins 78 do not face each other along the X-axis direction (pallet disengagement position) to a position where the fingers 72 and the pins 78 face each other along the X-axis direction (pallet engagement position), thereby engaging the fingers 72 with the pallet 76. This allows the arm 64 to stably hold the pallet 76. Furthermore, it is possible to prevent or suppress chips generated during machining from getting caught between the concave-shaped fingers 72 and the pins 78.

[0030] Here, the finger 72 is described as being formed in a concave shape facing the pallet 76 when viewed from the longitudinal direction of the arm 64, but this is not limited to this and any shape that can engage with the pin will suffice. For example, the finger may be formed in another shape, such as an open V-shape facing the pin when viewed from the longitudinal direction of the arm.

[0031] Furthermore, an arm protrusion 86 (not shown) extending toward the engagement side surface 76e is formed on the inside in the width direction facing the engagement side surface 76e of the arm engagement portion 68, i.e., on the inside in the X-axis direction. Also, a pallet groove 88 is formed in the engagement side surface 76e so as to be recessed inward of the pallet 76, and is configured so that the arm protrusion 86 can be inserted into it. This allows the arm 64 to hold the pallet 76 using both the fingers 72 and the arm protrusion 86, and therefore the pallet 76 can be held stably.

[0032] Note that, here, the finger 72 of the arm engaging portion 68 is described as being configured to be slidable between a pallet disengagement position and a pallet engagement position along the longitudinal direction of the arm engaging portion 68, i.e., the Z-axis direction, but this is not limiting, and the finger may be configured to hold the pallet by sliding in the X-axis direction, i.e., in the direction facing the pallet. In such a configuration, the finger does not displace in the longitudinal direction of the arm, so the arm can be made space-saving in the longitudinal direction and can be configured compactly.

[0033] The operation and effect of the pallet exchange device 44 of the machine tool 10 according to this embodiment will be described below through an explanation of the APC arm 50 that is operated to exchange the pallets 76, 94 as shown in FIGS.

[0034] 3, when the transfer of pallets 76, 94 begins in machine tool 10, APC arm drive mechanism 56 lowers APC arm 50, which is in the storage position, from second height position H2 to first height position H1. At this time, engagement pin 54a of engagement mechanism 54 is pulled out of guide hole 46a, and engagement is released. Then, revolving door 46, which was loaded on APC arm 50, is placed in a state where it is fitted into revolving door holding portion 48, replacing APC arm 50.

[0035] As shown in FIG. 4 , when the APC arm 50 descends to the first height position H1, the APC arm drive mechanism 56 rotates the APC arm 50 by 90 degrees (or 270 degrees). As a result, the first pallet holder 82 and the second pallet holder 84 of the APC arm 50 move along the rotation trajectory TR1 toward the C-axis rotary table 36 and the pallet orientation changing device 42 (the pallet exchange position), and the longitudinal direction of the APC arm 50 is aligned with the Z-axis direction. Furthermore, the arms 64 of the C-axis rotary table 36 and the pallet orientation changing device 42 move to the pallet transfer position. When the first pallet holder 82 and the second pallet holder 84 move toward the C-axis rotary table 36 and the pallet orientation changing device 42, the APC arm drive mechanism 56 raises the APC arm 50 to the second height position H2. As a result, the swing door 46 is placed on the APC arm 50 instead of the swing door holding portion 48, the engagement pin 54a is inserted into the guide hole 46a, and the swing door 46 and the APC arm 50 are engaged with each other.

[0036] As shown in FIG. 5 , when the APC arm 50 rises to the third height position H3 in the Y1 direction, the holding members 76f of the pallets 76, 94 fit into the recessed portions of the first pallet holder 82 and the second pallet holder 84, and the columnar members at both ends abut against the abutment side surface 76d of the pallet 76. This allows the APC arm 50 to hold the pallet 76, 94. At this point, the C-axis rotary table 36 releases the pallet holding mechanism, and the pallet position changing device 42 uses the fingers 72 to release its hold on the pallet. As a result, the pallet 76, 94 is transferred from the C-axis rotary table 36 and / or the pallet position changing device 42 to the APC arm 50. After transferring the pallet 76 to the APC arm 50, the C-axis rotary table 36 and / or the pallet position changing device 42 retract to a retracted position where they do not interfere with the rotating APC arm 50 or the rotating door 46.

[0037] When the APC arm 50 receives the pallets 76, 94, the APC arm drive mechanism 56 rotates the swing door 46 and the APC arm 50 holding the pallets 76, 94 together by 180 degrees (direction R2 in the figure). This allows the pallets 76, 94 held by the APC arm 50 to be swapped between the machining chamber 12 and the setup chamber 14. After swapping the pallets 76, 94, the C-axis rotary table 36 and / or the arm 64 of the pallet position change device 42 move from the retracted position to the pallet transfer position, and the swapped pallet 76 is held by the pallet holding mechanism of the C-axis rotary table 36 and the fingers 72 of the pallet position change device 42. Furthermore, the APC arm drive mechanism 56 lowers the APC arm 50 engaged with the swing door 46 to the second height position H2, and the swing door 46 that was loaded on the APC arm 50 is placed back on the swing door holder 48. Furthermore, the engagement pin 54a of the engagement mechanism 54 is pulled out of the guide hole 46a, thereby disengaging them. Next, the APC arm drive mechanism 56 lowers the APC arm 50 to the first height position H1 and then rotates it 90 degrees to move the first pallet holder 82 and the second pallet holder 84 below the swing door 46. Once the first pallet holder 82 and the second pallet holder 84 have moved below the swing door 46, the APC arm drive mechanism 56 raises the APC arm 50 to the second height position H2. Furthermore, the swing door 46 is loaded onto the APC arm 50 instead of the swing door holder 48, and the engagement pin 54a of the engagement mechanism 54 is inserted into the guide hole 46a, engaging the swing door 46 and the APC arm 50. As a result, the APC arm 50 is stored below the swing door 46 (see FIG. 3).

[0038] The pallet exchange device 44 according to this embodiment includes an APC arm 50 configured to be rotatable by an APC arm drive mechanism 56 in order to exchange pallets 76, 94; a pivoting door 46 disposed above the APC arm 50 and pivotable together with the APC arm 50 by engaging with an engagement mechanism 54 consisting of an engagement pin 54a and a guide hole 46a; and a chip cover 52 attached to the pivoting door 46 and covering the upper side of the APC arm 50 when the APC arm 50 is disposed along the width direction of the pivoting door 46 (when in the stored position). Therefore, when the first pallet holder 82 and the second pallet holder 84 for holding the pallets 76, 94 are not exposed from the lower side of the pivoting door 46 in order for the APC arm 50 to exchange the pallets 76, 94 between the setup chamber 14 and the machining chamber 12, i.e., when the APC arm 50 is in the stored position, the chip cover 52 can cover the APC arm 50, thereby preventing or suppressing chips from accumulating on the APC arm 50.

[0039] Furthermore, in the pallet exchange device 44 according to this embodiment, the engagement mechanism 54 is configured to include an engagement pin 54a that protrudes from the APC arm 50 toward the revolving door 46 (upward), and the revolving door 46 includes a guide hole 46a formed in the bottom thereof so that the engagement pin 54a can engage with the guide hole 46a. Therefore, by engaging the engagement pin 54a with the guide hole 46a, the APC arm 50 and the revolving door 46 can be stably engaged with each other.

[0040] Furthermore, with the pallet exchange device 44 according to this embodiment, as described above, when no workpiece is being transferred, such as when waiting for the machine tool 10 to machine the workpiece, the APC arm 50 can be positioned along the width direction of the swing door 46. Therefore, the first pallet holder 82 and the second pallet holder 84 do not protrude toward the machining chamber 12. This makes it possible to suppress (reduce) interference between the APC arm 50 and the Z-axis table 32, B-axis rotary table 34, and C-axis rotary table 36, and therefore the stroke of the Z-axis linear guide 38 can be made longer.

[0041] Furthermore, the pallet exchange device 44 according to this embodiment is provided with a swing door holder 48 on which the swing door 46 is placed in an engaged state when the swing door 46 is not swinging. The pallet exchange device 44 is configured so that the APC arm 50 and the swing door 46 are engaged with each other when the APC arm 50 is in a pallet exchange position where the longitudinal direction of the APC arm 50 is perpendicular to the width direction of the swing door 46, and when the APC arm 50 is in a storage position where the APC arm 50 is aligned with the width direction of the swing door 46, and the APC arm 50 loads the swing door 46. Therefore, the swing door 46 equipped with the chip cover 52 can always be stably held by the swing door holder 48 or the APC arm 50, and chips can be more effectively suppressed or prevented from accumulating on the APC arm 50 in the stored state.

[0042] As described above, according to the pallet changer 44 of the machine tool 10 according to this embodiment, accumulation of chips on the APC arm 50 can be suppressed or prevented.

[0043] While the APC arm 50 has been described here as being configured to be movable up and down, this is not limiting. The APC arm may be configured to only pivot depending on the structure of the pallet, and various types of engagement mechanisms may be used to accommodate this. In addition, in this embodiment, the APC arm is configured to hold and replace an upright pallet, but a pallet exchange mechanism that holds and replaces a horizontal pallet is also acceptable. Furthermore, since it is sufficient that there is no gap between the APC arm and the pivoting door, the APC arm may stop slightly below the second height position H2 rather than moving strictly to the second height position H2 when in the storage position.

[0044] Although the embodiment of the pallet changer 44 of the machine tool 10 has been described above, the present invention is not limited to the above embodiment. In addition to the above, it is believed that a person skilled in the art would understand that various modifications of the above embodiment are possible. [Explanation of symbols]

[0045] 10 Machine tools 12 Processing room 14 Preparation Room 44 Pallet exchange device 46 Swivel Door 46a Guide hole (engaged part) 50 APC arm (swivel arm) 52 Chip cover 54 Engagement mechanism 54a Engagement pin (engagement part) 56 APC arm drive mechanism (swivel mechanism)

Claims

1. A pallet changer for a machine tool, comprising: a rotating arm on both sides of which pallets can be placed, the rotating arm being configured to be rotatable by a rotating mechanism in order to exchange pallets between the setup chamber and the processing chamber; an engagement portion disposed on the pivot arm; a swing door disposed above the swing arm so as to separate the setup chamber from the processing chamber, the swing door having an engaged portion for engaging with the engaging portion, the swing door being swingable together with the swing arm when the engaged portion and the engaging portion are engaged; a chip cover attached to the swing door and covering an upper side of the swing arm when the longitudinal direction of the swing arm is arranged along the width direction of the swing door as viewed from the setup chamber side to the machining chamber side; A pallet changer for a machine tool, comprising:

2. a swing door holding portion that holds the swing door when the swing door does not swing, 2. A pallet exchange device for a machine tool according to claim 1, wherein the rotating arm and the rotating door are engaged with each other when the rotating arm is in a pallet exchange position in which the longitudinal direction of the rotating arm is perpendicular to the width direction of the rotating door, and when the rotating arm is in a storage position arranged along the width direction of the rotating door.

3. A pallet exchange device for a machine tool as described in claim 1 or claim 2, wherein the engaging portion and the engaged portion are an engaging pin protruding from the swivel arm and a guide hole formed in the bottom of the swivel door so as to be engageable with the engaging pin, or an engaging pin protruding from the bottom of the swivel door and a guide hole formed in the swivel arm so as to be engageable with the engaging pin.

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