JP7569700B2 - Machine Tools - Google Patents

Description

The present invention relates to a machine tool capable of machining a workpiece placed on a pallet.

Conventionally, machine tools capable of machining a workpiece placed on a pallet are known. In such machine tools, machining of the workpiece is performed in a state in which a predetermined reference direction in the machine body and a reference surface of the workpiece are set parallel to each other, i.e., the parallelism of the workpiece is set within an acceptable range.

The machine tool described in Patent Document 1 includes a table that transports a pallet to a machining area around the spindle, and a correction unit that corrects the position of the pallet relative to the table when the position of the workpiece relative to the pallet is misaligned. The correction unit has a pair of pressing blocks that press the right side surface of the pallet in a plan view, and a pair of stopper blocks that restrain the left side surface of the pallet. The pair of pressing blocks are arranged at intervals from each other in the front-rear direction along the right side surface, and the pair of stopper blocks are arranged at intervals from each other in the front-rear direction along the left side surface. Furthermore, one of the pair of stopper blocks is capable of moving forward and backward along a horizontal direction that intersects with the left side surface of the pallet by receiving a driving force from an actuator. When a touch sensor detects two reference surfaces of the workpiece and detects a deviation in the parallelism of the workpiece relative to the machine body, the correction unit moves the one stopper block forward and backward in accordance with the amount of deviation to adjust the position of the pallet, thereby adjusting the parallelism of the workpiece relative to the machine body regardless of the relative position of the workpiece relative to the pallet.

Japanese Utility Model Application Publication No. 61-148546

However, in the machine tool described in Patent Document 1, the relative position of the pallet to the machine body cannot be adjusted with high precision, and the movement of the pallet may be repeated multiple times to achieve the target parallelism. Specifically, in the above technology, the amount of advance and retreat of one of the stopper blocks is adjusted while two pressing blocks are each pressing against the left side surface of the pallet. Therefore, if the pressing forces of the two pressing blocks or the frictional force against the pallet change, even if the amount of advance and retreat of the stopper blocks is the same, variations are likely to occur in the amount and direction of movement of the pallet, making it difficult to stably move the pallet to the target position.

The present invention aims to provide a machine tool that can easily and accurately adjust the parallelism of a workpiece relative to the machine body.

A machine tool according to one aspect of the present invention includes a machine body having a coordinate axis perpendicular to the vertical direction, a table having a mounting surface facing upward and supported by the machine body, a pallet, a tool support unit, a parallelism measuring unit, a first positioning pin, a second positioning pin, a clamp unit, and a parallelism adjustment unit. The pallet is detachably mounted on the mounting surface of the table. The pallet has a pallet upper surface portion capable of supporting a workpiece having a reference surface extending in the vertical direction, a pallet lower surface portion disposed opposite the pallet upper surface portion and facing the mounting surface, a first pin receiving portion disposed on the pallet lower surface portion, and a second pin receiving portion disposed on the pallet lower surface portion at a distance from the first pin receiving portion in a direction parallel to the mounting surface. The tool support unit is supported by the machine body and is capable of supporting a tool for machining the workpiece. The parallelism measuring unit is capable of measuring the parallelism, which is the relative angle of the reference surface of the workpiece with respect to the coordinate axis in a plan view. The first positioning pin extends in a vertical direction and is supported on the table so as to be movable in a vertical direction relative to the placement surface, and is engageable with the first pin receiving portion so as to rotate the pallet relative to the table around the first positioning pin. The second positioning pin is disposed at a distance from the first positioning pin in a pin arrangement direction that is a direction parallel to the placement surface, extends in a vertical direction, and is supported on the table so as to be movable in a vertical direction relative to the placement surface. The second positioning pin is engageable with the second pin receiving portion so as to allow the pallet to move in the pin arrangement direction relative to the second positioning pin and to restrain the pallet in an adjustment direction that is parallel to the placement surface and perpendicular to the pin arrangement direction. The clamp portion is disposed on the table and is switchable between a clamped state and an unclamped state, the clamped state being a state in which the pallet is prevented from moving relative to the table in a direction parallel to the placement surface and allows the tool to machine the workpiece, and the unclamped state being a state in which the pallet is allowed to move relative to the table. The parallelism adjustment unit can adjust the parallelism of the workpiece by moving the second positioning pin in the adjustment direction while the first positioning pin and the second positioning pin are engaged with the first pin receiving portion and the second pin receiving portion, respectively, and the clamping portion is switched to the non-clamped state, thereby rotating the pallet around the first positioning pin.

According to this configuration, the parallelism of the workpiece on the pallet can be adjusted with the first positioning pin and the second positioning pin engaged with the first pin receiving portion and the second pin receiving portion, respectively, so that the pallet is allowed to rotate around the first pin receiving portion during the adjustment operation, but the pallet is restricted from moving in other directions along the table's mounting surface. This prevents the pallet from moving in a direction different from the target direction, and the parallelism of the workpiece can be adjusted with high precision by the rotational movement of the pallet. In addition, the second positioning pin engages with the second pin receiving portion so as to allow the pallet to move relative to the second positioning pin in the pin arrangement direction and to restrain the pallet in the adjustment direction, so that the pallet can be rotated stably and easily in response to the linear movement of the second positioning pin along the adjustment direction by the parallelism adjustment unit.

In the above configuration, it is preferable that the parallelism adjustment unit has an adjustment drive unit capable of receiving an adjustment command signal and moving the second positioning pin in the adjustment direction in response to the adjustment command signal, a movement amount calculation unit that calculates the movement amount of the second positioning pin so that the reference surface of the workpiece becomes parallel to the coordinate axis in response to the measurement result of the parallelism measurement unit, and a movement control unit that inputs the adjustment command signal to the adjustment drive unit in response to the movement amount calculated by the movement amount calculation unit.

With this configuration, the parallelism of the workpiece can be automatically adjusted according to the current parallelism measurement result measured by the parallelism measurement unit.

In the above configuration, it is preferable that the first positioning pin has a conical first tip, the first pin receiving portion has a conical inner surface that can abut against the first tip along the circumferential direction, the second positioning pin has a second tip including a pair of ridges that are spaced apart from each other in the adjustment direction and extend along the pin alignment direction, the second pin receiving portion has a pair of inclined surfaces that are spaced apart from each other in the adjustment direction and extend in the pin alignment direction and are inclined so as to approach each other upwardly and can abut against the pair of ridges, and the dimensions of the second positioning pin and the second pin receiving portion in the pin alignment direction are each set so that the pair of inclined surfaces abut against the pair of ridges, respectively, and the second pin receiving portion can move relative to the second positioning pin in the pin alignment direction while restricting the relative movement of the second pin receiving portion in the adjustment direction relative to the second positioning pin.

According to this configuration, the first positioning pin having a conical first tip engages with the first pin receiving portion, so that the movement of the pallet can be stably restricted to a rotational movement around the first positioning pin, and the pair of ridges of the second positioning pin abut against the pair of inclined surfaces of the second pin receiving portion, respectively, so that the pallet can be moved relative to the second positioning pin in the pin arrangement direction while being restrained in the adjustment direction, thereby realizing stable rotational movement of the pallet.

In the above configuration, it is preferable that the pallet has at least one pallet engagement part arranged on the lower surface of the pallet, the clamp part has at least one clamp member, a clamp drive part, and a clamp control part, and the machine tool further includes a pin drive part. The at least one clamp member is supported on the table so as to be movable in the vertical direction relative to the placement surface between a clamp position and an unclamped position. The clamp position is a position where the at least one clamp member presses the at least one pallet engagement part downward to restrain the pallet, thereby placing the clamp part in the clamped state, and the unclamped position is a position above the clamp position where the at least one clamp member separates from the at least one pallet engagement part to release the restraint of the pallet, thereby placing the clamp part in the unclamped state. The clamp drive part is capable of receiving a clamp command signal and moving the at least one clamp member in the vertical direction in response to the clamp command signal. The clamp control part inputs the clamp command signal to the clamp drive part and switches the at least one clamp member between the clamp position and the unclamped position. The pin drive unit is capable of lowering the first positioning pin and the second positioning pin so that the first positioning pin and the second positioning pin maintain their engagement with the first pin receiving portion and the second pin receiving portion, respectively, as the clamp control unit switches the at least one clamp member from the unclamped position to the clamped position.

With this configuration, the first positioning pin and the second positioning pin can be kept engaged with the first pin receiving portion and the second pin receiving portion, respectively, during the clamping operation, preventing the pallet from moving in a direction parallel to the mounting surface and enabling the relative position of the pallet to be stably maintained with respect to the table.

In the above configuration, the first positioning pin and the second positioning pin are supported on the table so as to be vertically movable between a positioning position and a non-positioning position, the positioning position is a position where the first positioning pin and the second positioning pin engage with the first pin receiving portion and the second pin receiving portion, respectively, and the non-positioning position is a position below the positioning position where the first positioning pin and the second positioning pin are detached from the first pin receiving portion and the second pin receiving portion, respectively, and the pin drive unit is at least one hydraulic chamber that is equipped with a hydraulic source that supplies hydraulic oil and a plurality of hydraulic chambers therein, and receives hydraulic oil supplied from the hydraulic source into one of the plurality of hydraulic chambers and discharges hydraulic oil from the other hydraulic chambers of the plurality of hydraulic chambers, thereby moving the first positioning pin and the second positioning pin in the vertical direction. It is preferable that the device has one hydraulic cylinder, at least one control valve that is interposed between the hydraulic power source and the at least one hydraulic cylinder and switches the first positioning pin and the second positioning pin between the positioning position and the non-positioning position by switching the supply destination of the hydraulic oil supplied from the hydraulic power source among the multiple hydraulic chambers, and a pressure adjustment valve that is interposed between the control valve and the at least one hydraulic cylinder and is capable of discharging a portion of the hydraulic oil between the control valve and the at least one hydraulic cylinder in response to the force that the first positioning pin and the second positioning pin receive from the pallet when the clamp control unit switches the at least one clamp member from the non-clamping position to the clamping position with the first positioning pin and the second positioning pin positioned at the positioning position.

With this configuration, compared to when the lowering motion of the first positioning pin and the second positioning pin are individually controlled in response to the lowering of the clamping member, the occurrence of gaps between each positioning pin and each pin receiving portion is prevented, and it is possible to clamp the pallet while stably maintaining the relative position of the pallet to the table.

In the above configuration, it is preferable that the apparatus further includes a first positioning unit that supports the first positioning pin, the first positioning unit having a first support frame supported on the table, a first linear guide mechanism that is attached to the first support frame and supports the first positioning pin so as to guide the first positioning pin in the vertical direction, and a first preload mechanism that is attached to the first support frame and applies a preload to the first linear guide mechanism to prevent the first positioning pin from displacing relative to the first support frame in a direction perpendicular to the vertical direction.

This configuration prevents the first positioning pin from being displaced or falling during machining of the workpiece or rotation of the pallet, and allows the position of the pallet to be stably maintained.

In the above configuration, it is preferable to further include a second positioning unit that supports the second positioning pin, the second positioning unit having a second support frame supported on the table, a second linear guide mechanism that is attached to the second support frame and supports the second positioning pin so as to guide the second positioning pin in the vertical direction, and a second preload mechanism that is attached to the second support frame and applies a preload to the second linear guide mechanism to prevent the second positioning pin from displacing relative to the second support frame in a direction perpendicular to the vertical direction.

This configuration prevents the second positioning pin from being displaced or falling during machining operations on the workpiece or during rotation of the pallet, and the position of the pallet can be stably maintained. In particular, during rotation, the movement direction of the second positioning pin differs from the movement direction of the second pin receiving portion of the pallet, so the second positioning pin is likely to be subjected to a large load. Even in such cases, the above-mentioned preload mechanism allows the second positioning pin to move stably and the pallet to rotate stably.

In the above configuration, it is preferable that the second support frame is supported on the table so as to be movable in the adjustment direction, and the parallelism adjustment unit moves the second support frame of the second positioning unit in the adjustment direction to move the second positioning pin and adjust the parallelism of the workpiece.

With this configuration, the pallet can be rotated while maintaining high rigidity of the second positioning part compared to when the second positioning pin is moved alone.

In the above configuration, it is preferable to further include a linear scale attached to one of the table and the second support frame, and a scale head attached to the other of the table and the second support frame that is different from the one of the table and the second support frame and capable of reading the linear scale.

With this configuration, the amount of movement of the second positioning pin can be accurately detected based on the reading results of the scale head, and the detection result can be fed back to the command signal by the drive control unit.

The present invention provides a machine tool that can easily and accurately adjust the parallelism of a workpiece relative to the machine body by moving a pallet that supports the workpiece.

1 is a perspective view of a machine tool according to a first embodiment of the present invention; FIG. 2 is a plan view for explaining a movement range of a table of the machine tool according to the first embodiment of the present invention. 1 is a block diagram of a machine tool according to a first embodiment of the present invention. FIG. FIG. 1 is a plan view of a table of a machine tool according to a first embodiment of the present invention. FIG. 1 is a side view of a table of a machine tool according to a first embodiment of the present invention. 6 is a front cross-sectional view taken along the arrow VI-VI in FIG. 4. 7 is a front cross-sectional view taken along the arrow VII-VII position in FIG. 4. 8 is a front cross-sectional view taken along the arrow VIII-VIII in FIG. 4. FIG. 2 is a perspective view of a first positioning unit of the machine tool according to the first embodiment of the present invention. FIG. 2 is a plan view of a first positioning unit of the machine tool according to the first embodiment of the present invention. FIG. 2 is a side cross-sectional view of a first positioning portion of the machine tool according to the first embodiment of the present invention. FIG. 2 is a plan view showing the relative positional relationship between a first positioning portion of the machine tool according to the first embodiment of the present invention and a first pin receiving portion of a pallet. FIG. 2 is a perspective view of a second positioning unit and a turning unit of the machine tool according to the first embodiment of the present invention. FIG. 2 is a plan view of a second positioning unit and a turning unit of the machine tool according to the first embodiment of the present invention. 4 is a side cross-sectional view of a second positioning unit and a turning unit of the machine tool according to the first embodiment of the present invention. FIG. 4 is a plan view showing the relative positional relationship between the second positioning portion and the turning portion of the machine tool according to the first embodiment of the present invention and the second pin receiving portion of the pallet. FIG. FIG. 2 is a schematic diagram showing a state in which a pallet is turned in the machine tool according to the first embodiment of the present invention. FIG. 2 is a schematic diagram illustrating the amount of rotation of a pallet in the machine tool according to the first embodiment of the present invention. 1 is a hydraulic circuit diagram of a machine tool according to a first embodiment of the present invention. FIG. 5 is a flowchart of an operation for adjusting parallelism of a workpiece in the machine tool according to the first embodiment of the present invention. FIG. 2 is a schematic front view showing how the parallelism of a workpiece is measured in the machine tool according to the first embodiment of the present invention. 1 is a plan view showing a machining reference surface of a workpiece in a machine tool according to a first embodiment of the present invention. FIG. 13 is a graph showing the relationship between the clearance and the displacement of a linear motion guide mechanism. FIG. 11 is a perspective view of a first positioning unit of a machine tool according to a second embodiment of the present invention. FIG. 11 is a plan view of a first positioning unit of a machine tool according to a second embodiment of the present invention. FIG. 11 is a perspective view of a second positioning unit and a turning unit of a machine tool according to a second embodiment of the present invention. FIG. 11 is a plan view of a second positioning unit and a turning unit of a machine tool according to a second embodiment of the present invention.

Each embodiment of the present invention will be described in detail below with reference to the attached drawings. Fig. 1 is a perspective view of a machine tool 1 according to a first embodiment of the present invention. The machine tool 1 performs a predetermined process on a workpiece W (object to be machined) (Figs. 17, 21, 22), and is, as an example, a gantry-type machine tool with an automatic pallet change function. The machine tool 1 can process a workpiece W having a complex shape, such as a casting material that is used as a material for automobile press dies. Referring to Fig. 1, the machine tool 1 includes a machine body 100, a table 20, and a pallet 30.

In FIG. 1, the front-rear direction is defined based on the direction of movement of table 20 as described below, and the horizontal direction perpendicular to the front-rear direction is defined as the left-right direction. Furthermore, the direction perpendicular to the front-rear direction and the left-right direction is defined as the up-down direction. These definitions of directions are intended to explain the structure, function, and usage of machine tool 1, and do not limit the machine tool according to the present invention. The front-rear direction constitutes the X-axis (coordinate axis) of machine tool 1, the up-down direction constitutes the Z-axis of machine tool 1, and the left-right direction constitutes the Y-axis of machine tool 1. The X-axis is perpendicular to the Z-axis (up-down direction) and the Y-axis.

The machine body 100 constitutes the main body of the machine tool 1 and corresponds to a housing for performing a predetermined processing on the workpiece W. The machine body 100 has a bed 10, a processing unit 41, a table drive unit 21, a pair of left and right receiving tables 11, a frame 40, and a saddle 42.

The bed 10 has a rectangular shape that has a certain width in the left-right direction and extends long in the front-rear direction, and constitutes the base part of the machine body 100. The bed 10 is installed (fixed) at the work site of the machine tool 1. The bed 10 has an upper surface (support surface) that faces upward.

The machining unit 41 is disposed above the upper surface of the bed 10 and is capable of machining the workpiece W. In a gate-type machine tool such as that of this embodiment, the machining unit 41 is supported by the frame 40. The machining unit 41 has a spindle 40S (see FIG. 21, not shown in FIG. 1, also called a tool support unit) that extends in the vertical direction. A machining attachment (a tool for machining the workpiece W) (not shown) is removably attached to the spindle 40S. In other words, the spindle 40S is supported by the machine body 100 and is capable of supporting the tool. Furthermore, a measurement probe 66 (FIG. 21), which will be described later, is removably attached to the spindle 40S.

The table 20 is a plate-like member extending in the front-rear and left-right directions. The table 20 has a support surface facing upward, and is supported on the upper surface of the bed 10 so that it can move in the front-rear direction below the processing section 41. The table 20 is made of a metal material such as iron.

The table driving unit 21 moves the table 20 in the front-rear direction. The table driving unit 21 has a motor 22 and a ball screw 23. The ball screw 23 is attached to the bed 10 so as to extend in the front-rear direction, and rotates by receiving the rotational driving force of the motor 22, while moving the table 20 in the front-rear direction. For this reason, the table 20 has a nut portion (not shown) that engages with the threaded portion of the ball screw 23.

The pallet 30 is removably placed on the aforementioned mounting surface of the table 20 so that it can move forward and backward together with the table 20, and supports the workpiece W.

The frame 40 has a gate shape as shown in FIG. 1 and supports the processing unit 41 so that the processing unit 41 can move on a moving surface including the up-down and left-right directions. The frame 40 has a pair of left and right columns 40A and a cross rail 40B that connects the pair of left and right columns 40A to each other in the left-right direction.

The saddle 42 is supported on the cross rail 40B of the frame 40 so that it can move left and right, and supports the processing section 41 mentioned above.

The machine body 100 further includes a pair of left and right motors 451 and ball screws 452, a motor 461 and ball screws 462, a motor 471 and ball screws 472, an operating unit 48, and an AAC (Auto Attachment Changer) device 55.

The pair of left and right motors 451 and ball screws 452 move the cross rail 40B up and down relative to the pair of left and right columns 40A. The motor 461 and ball screw 462 move the saddle 42 left and right on the cross rail 40B. The motor 471 and ball screw 472 move the processing unit 41 up and down relative to the saddle 42. In this embodiment, each of the motors is a known servo motor. The drive targets driven by each motor include nuts (not shown) that engage with each ball screw, similar to the table 20 described above.

The operation unit 48 is operated by an operator (machine operator) to issue machining commands to the machine tool 1 using an NC program and to perform various manual operations. The operation unit 48 is supported on the frame 40 so that it can swing and move with the operator.

The AAC device 55 is disposed in front of the left column 40A as shown in FIG. 1. The AAC device 55 is capable of automatically attaching and detaching machining attachments to the spindle 40S of the machining section 41, and stores multiple machining attachments.

2 is a plan view for explaining the range of movement of the table 20 of the machine tool 1 according to this embodiment. As described above, the table driving unit 21 moves the table 20 in the front-rear direction. The table driving unit 21 can move the table 20 in the front-rear direction in the machining area, which is an area where the machining unit 41 can machine the workpiece W. The machining area includes a machining rear end area P1, which is the rear end of the machining area, and a machining front end area P2, which is the front end of the machining area. In FIG. 2, the table 20 arranged in the machining rear end area P1 is shown by a dashed line, and the table 20 arranged in the machining front end area P2 is shown by a two-dot chain line. That is, the pallet 30 is placed on the table 20, and while the table 20 moves from the machining front end area P2 to the machining rear end area P1 in FIG. 2, the machining unit 41 can machine the workpiece W on the pallet 30. At this time, the machining unit 41 is also moved up and down and left and right in accordance with the shape of the workpiece W as described above.

Furthermore, the table driving unit 21 can move the table 20 in the front-rear direction between the processing area and a pallet exchange position P3, which is a position further forward than the processing area and where the pallet 30 can be attached and detached to the table 20. In FIG. 2, the table 20 placed at the pallet exchange position P3 is shown by a solid line. In this embodiment, when the table 20 is placed at the pallet exchange position P3, the pallet 30 can be exchanged in the left-right direction with respect to the table 20. On both the left and right sides of the pallet exchange position P3, a pair of left and right receiving tables 11 capable of supporting the pallet 30 are arranged (FIG. 1). In FIG. 2, S1 indicates a processing movement stroke for the table 20 to move between the processing front end area P2 and the processing rear end area P1, and S2 indicates an exchange movement stroke (exchange movement distance) for the table 20 to move between the processing area and the pallet exchange position P3.

As an example, when the pallet 30 is placed on the table 20 as shown in FIG. 2, when the pallet 30 is transferred to the receiving stand 11 on the left side of FIG. 1 (see the direction indication in FIG. 1), the pallet 30B on the right side of FIG. 2 can be placed on the table 20. Similarly, when the pallet 30 is transferred to the receiving stand 11 on the right side of FIG. 1, the pallet 30A on the left side of FIG. 2 can be placed on the table 20. Also, in the state shown in FIG. 2, when the pallet 30 on the table 20 is detached forward, either the pallet 30A or the pallet 30B may be placed on the table 20. In this embodiment, the machine body 100 has a pair of left and right receiving stand cylinders 31 and a pair of left and right guide rails 35. The pair of left and right receiving stand cylinders 31 have a cylinder structure that can move (transfer) the pallet 30 (30A, 30B) between the pair of left and right receiving stands 11.

In this embodiment, the machining end region P1 corresponds to the origin for the forward and backward movement of the table 20 (the machine origin in the forward and backward direction). When machining the workpiece W, machining is performed based on a workpiece coordinate system that sets a reference surface and machining origin on the workpiece W, rather than a machine coordinate system that includes the above-mentioned machine origin.

Figure 3 is a block diagram of the machine tool 1 according to this embodiment.

Referring to FIG. 3, the machine tool 1 further includes a control unit 50, a spindle drive unit 60, a first positioning unit 61, a second positioning unit 62, a clamp unit 63, a rotating unit 64, a plurality of check sensors 65, and a measurement probe 66.

The control unit 50 is composed of a CPU (Central Processing Unit), a memory that stores an NC program, a memory used as a working area for the CPU, and the like. The control unit 50 functions as having a drive control unit 500 (movement control unit, clamp control unit), a numerical control unit 501, and a memory unit 502, as a result of the CPU executing the NC program. As shown in FIG. 3, the control unit 50 is connected to the table drive unit 21 and the receiving cylinder 31, the spindle drive unit 60, the first positioning unit 61, the second positioning unit 62, the clamp unit 63, the rotating unit 64, a number of check sensors 65, and a measurement probe 66.

The drive control unit 500 inputs command signals to the table drive unit 21, the support cylinder 31, the spindle drive unit 60, the first positioning unit 61, the second positioning unit 62, the clamp unit 63, and the rotating unit 64, and controls the operation of these drive mechanisms.

The numerical control unit 501 controls the parallelism adjustment operation of the workpiece W executed in the machine tool 1. Specifically, the numerical control unit 501 has a parallelism calculation unit 501A and a rotation command unit 501B (movement amount calculation unit). The parallelism calculation unit 501A calculates the parallelism of the workpiece W based on the measurement results of the measurement probe 66. The rotation command unit 501B inputs a command signal to the rotation unit 64 based on the calculation results of the parallelism calculation unit 501A, and rotates the pallet 30 (workpiece W).

The memory unit 503 pre-stores various thresholds, parameters, etc. referenced by the drive control unit 500 and the numerical control unit 501.

The spindle drive unit 60 includes the aforementioned motors 451, 461, and 471, and moves the spindle 40S (Figure 1) to machine the workpiece W or to measure the parallelism of the workpiece W.

The first positioning unit 61 and the second positioning unit 62 are each arranged on the table 20 and have the function of positioning the pallet 30 relative to the table 20.

The clamping portion 63 is disposed on the table 20, and has the function of fixing the table 20 and the pallet 30 to each other when the first positioning portion 61 and the second positioning portion 62 have positioned the pallet 30, thereby preventing the pallet 30 from moving relative to the table 20.

The rotating unit 64 is disposed on the table 20 and has the function of rotating the pallet 30 around a central axis of rotation CL (FIG. 17) (first positioning pin 610 described below) that extends vertically relative to the table 20 in order to adjust the parallelism of the workpiece W.

The multiple check sensors 65 are attached to each part of the machine tool 1, and detect whether each drive mechanism, table 20, and pallet 30 are operating normally based on the control of the control unit 50. As an example, each check sensor 65 is composed of a limit sensor, a photo sensor, etc.

The measurement probe 66 is removably attached to the spindle 40S and is used to measure the reference surface of the workpiece W. When the measurement probe 66 comes into contact with the reference surface, it inputs a predetermined contact signal to the control unit 50.

The measurement probe 66, the parallelism calculation unit 501A of the control unit 50, and the spindle drive unit 60 constitute the parallelism measurement unit 101 of the present invention. The parallelism measurement unit 101 is capable of measuring the parallelism, which is the relative angle of the reference surface of the workpiece W with respect to the X-axis (a coordinate axis extending in the front-rear direction) in a plan view.

Next, the structures of the table 20, pallet 30, first positioning unit 61, second positioning unit 62, clamp unit 63 and swivel unit 64 of the machine tool 1 according to this embodiment will be described in more detail.

Figure 4 is a plan view of the table 20 of the machine tool 1. Figure 5 is a side view of the table 20. Figure 6 is a front cross-sectional view at the position of the arrows VI-VI in Figure 4. Figure 7 is a front cross-sectional view at the position of the arrows VII-VII in Figure 4. Figure 8 is a front cross-sectional view at the position of the arrows VIII-VIII in Figure 4.

Referring to FIG. 4, three rails 200 are arranged on the top surface of the table 20. The three rails 200 are arranged at intervals in the front-rear direction and each extends in the left-right direction. As shown in FIG. 4, the above-mentioned receiving cylinder 31 can be engaged with the table 20, and the receiving cylinder 31 can transport the pallet 30 from the left side of FIG. 4 onto the table 20. At this time, the pallet 30 moves along the three rails 200.

Furthermore, six clamping parts 63 are arranged on the upper surface of the table 20. The six clamping parts 63 are each for fixing the pallet 30 to the table 20, and three clamping parts 63 are arranged in two rows, one on the left and one on the right, at intervals in the front-rear direction. Each clamping part 63 is arranged so as to form a part of the rail 200. The clamping part 63 can be switched between a clamping state and an unclamping state. The clamping state is a state in which the clamping part 63 prevents the pallet 30 from moving relative to the table 20 in a direction parallel to the mounting surface of the table 20, and the clamping part 63 allows the workpiece W to be machined by a tool attached to the spindle 40S. On the other hand, the unclamping state is a state in which the clamping part 63 allows the pallet 30 to move relative to the table 20.

A first positioning unit 61 is disposed at the rear end and right end of the table 20, and a second positioning unit 62 and a rotating unit 64 are disposed at the front end and right end of the table 20.

Furthermore, referring to FIG. 5, a plurality of pallet support parts 201 are arranged on the upper surface of the table 20. Each pallet support part 201 is a convex part extending in the left-right direction, and the upper surface parts (top parts) of the plurality of pallet support parts 201 form the support surface of the table 20. As shown in FIG. 5, the aforementioned rail 200, first positioning part 61, second positioning part 62 and swivel part 64 are respectively arranged between adjacent pallet support parts 201.

On the other hand, the pallet 30 has a rectangular shape in a plan view and a predetermined height in the vertical direction. The pallet 30 has a pallet upper surface portion capable of supporting the workpiece W, and a pallet lower surface portion disposed opposite the pallet upper surface portion and facing the placement surface of the table 20. The pallet upper surface portion corresponds to the upper surface portion of the pallet 30, and the pallet lower surface portion corresponds to the lower surface portion of the pallet 30. The pallet 30 also has six pallet recesses 301 formed on the pallet lower surface portion, and six pallet guide portions 302 (pallet engagement portions) attached to the six pallet recesses 301, respectively. Note that the number of pallet recesses 301 and pallet guide portions 302 is not limited to six, and at least one of each may be disposed depending on the structure, shape, etc. of the pallet 30.

Referring to FIG. 6, the pallet recess 301 is a rectangular recess formed on the underside of the pallet 30, and the pallet guide section 302 is fitted (fixed) into the pallet recess 301. The pallet guide section 302 has a U-shape that opens downward, and the rail 200 or the clamp plate 631 of the clamp section 63 can be received in the space 305 formed therein. In addition, a roller 303 is rotatably supported in the center of the pallet guide section 302 so that a part of the circumferential surface is exposed in the space 305. Furthermore, of the six pallet guide sections 302, in addition to the above-mentioned roller 303, a pair of left and right side rollers 304 (FIG. 7) are rotatably supported in the two pallet guide sections 302 on the left and right in the center in the front-rear direction.

Furthermore, the pallet 30 has a first pin receiving portion 30P (see Figures 11 and 12) arranged on the underside of the pallet, and a second pin receiving portion 30Q (see Figures 15 and 16) arranged on the underside of the pallet at a distance from the first pin receiving portion 30P in a direction parallel to the placement surface.

The first pin receiving portion 30P is a hole formed in the lower surface (pallet lower surface) of the pallet 30 so as to face the first positioning portion 61 (first positioning pin 610) of the table 20 when the pallet 30 is placed on the table 20. In this embodiment, the first pin receiving portion 30P has a conical (frustum-shaped) inner peripheral surface (FIG. 11). Similarly, the second pin receiving portion 30Q is a hole formed in the lower surface (pallet lower surface) of the pallet 30 so as to face the second positioning portion 62 (second positioning pin 620) of the table 20 when the pallet 30 is placed on the table 20. In this embodiment, the second pin receiving portion 30Q has a pair of inclined surfaces 30Q1 (FIGS. 15 and 16). The detailed structures and functions of the first pin receiving portion 30P and the second pin receiving portion 30Q will be described in more detail later.

When the receiving cylinder 31 transports the pallet 30 onto the table 20, the three pallet guide sections 302 on the right side of the pallet 30 first engage with the left ends (see the direction indication in FIG. 4) of the three rails 200 on the table 20 in FIG. 4. Then, with the rails 200 positioned within the spaces 305 (FIG. 6) of the pallet guide sections 302, the receiving cylinder 31 transports the pallet 30 onto the table 20 while the rollers 303 and side rollers 304 roll. At this time, in the six clamp sections 63, the clamp plates 631 (clamp members) of the clamp sections 63 are positioned within the spaces 305 of the six pallet guide sections 302, as shown in FIG. 6.

The clamping section 63 has a clamping cylinder 632 (Figure 6) in addition to the clamping plate 631 described above.

The clamp plate 631 is supported by the table 20 so that it can move vertically relative to the placement surface of the table 20 between a clamp position and an unclamped position. The clamp position is a position where the clamp plate 631 presses downward on a pair of left and right pressed portions 302A (FIG. 6) of the pallet guide portion 302 to restrain the pallet 30, thereby placing the clamp portion 63 in the clamped state. On the other hand, the unclamped position is a position above the clamp position where the clamp plate 631 moves slightly away from the pressed portions 302A of the pallet guide portion 302 to release the restraint on the pallet 30, thereby placing the clamp portion 63 in the unclamped state.

The clamp cylinder 632 is made of a hydraulic cylinder and receives a supply of hydraulic oil to move the clamp plate 631 up and down. The clamp cylinder 632 has a cylinder body and a cylinder rod (see FIG. 19). The cylinder rod moves up and down relative to the cylinder body. The clamp plate 631 is fixed to the tip (upper end) of the cylinder rod.

Figures 9, 10, and 11 are perspective, plan, and side cross-sectional views of the first positioning part 61 (first positioning unit) of the machine tool 1 according to this embodiment. Figure 12 is a plan view showing the relative positional relationship between the first positioning part 61 of the machine tool 1 according to this embodiment and the first pin receiving part 30P of the pallet 30.

The first positioning unit 61 has a first positioning pin 610, a base unit 61S (first support frame), a pair of left and right blocks 611 (first support frame), a pair of left and right linear guides 612 (first linear guide mechanisms), four linear roller bearings 613 (first linear guide mechanisms) on the front, rear, left and right, a pair of front and rear tension bars 614 (first preload mechanisms), and a number of nuts 615 (first preload mechanisms) attached to both ends of each tension bar 614.

The first positioning pin 610 extends in the vertical direction and is supported on the table 20 via the base portion 61S so that it can move in the vertical direction relative to the support surface of the table 20. The first positioning pin 610 is engageable with the first pin receiving portion 30P described above so that the pallet 30 can rotate relative to the table 20 around the first positioning pin 610.

In this embodiment, the first positioning pin 610 has a round tapered pin shape and has a first tip 610A that is conical or truncated cone-shaped as shown in FIG. 11. On the other hand, the first pin receiving portion 30P has a conical or truncated cone-shaped inner surface that can abut against the first tip 610A in the circumferential direction (FIG. 11). When the pallet 30 is transported onto the table 20 as shown by the arrow in FIG. 12 and the first tip 610A of the first positioning pin 610 shown in FIG. 11 engages with the first pin receiving portion 30P from below, the first pin receiving portion 30P becomes capable of horizontal rotation around the first positioning pin 610 and the first pin receiving portion 30P is prevented from moving in the horizontal direction relative to the first positioning pin 610. The first positioning pin 610 is moved up and down by a hydraulic cylinder 61P (FIG. 11).

The base portion 61S is a plate-like member fixed to the upper surface of the table 20 by a number of bolts. A pair of left and right blocks 611 are fixed to the base portion 61S at a distance from each other in the left-right direction and have a rectangular parallelepiped shape. A first positioning pin 610 is disposed between the pair of left and right blocks 611 so as to be movable in the up-down direction. The base portion 61S and the pair of left and right blocks 611 constitute the first support frame of the present invention.

The pair of left and right linear guides 612 and the four linear roller bearings 613 constitute the first linear guide mechanism of the present invention. These members are supported by the first support frame and support the first positioning pin 610 so as to guide the first positioning pin 610 in the up-down direction. The linear guides 612 and linear roller bearings 613 house rollers (rolling elements) (not shown).

The pair of front and rear tension bars 614 are arranged to connect the pair of left and right blocks 611 to each other on both the front and rear sides. In Figures 9 and 10, by tightening each nut 615, a preload can be applied to each block 611 in a direction that brings the blocks 611 closer to each other. In other words, each tension bar 614 and each nut 615 constitutes the first preload mechanism of the present invention. The first preload mechanism is attached to the first support frame, and by applying a preload to the first linear guide mechanism, it prevents the first positioning pin 610 from displacing relative to the first support frame in a direction perpendicular to the up-down direction.

Figures 13, 14, and 15 are perspective views, plan views, and side cross-sectional views of the second positioning section 62 (second positioning unit) and the swivel section 64 of the machine tool 1 according to this embodiment. Figure 16 is a plan view showing the relative positional relationship between the second positioning section 62 and the swivel section 64 of the machine tool 1 according to this embodiment and the second pin receiving section 30Q of the pallet 30.

The second positioning unit 62 has a second positioning pin 620, a base unit 62S (second support frame), a pair of left and right blocks 621 (second support frame), a pair of left and right linear guides 622 (second linear guide mechanism), four linear roller bearings 623 (second linear guide mechanism) on the front, rear, left and right, a pair of front and rear tension bars 624 (second preload mechanism), and a number of nuts 625 (second preload mechanism) attached to both ends of each tension bar 624.

The second positioning pin 620 extends in the vertical direction and is supported by the table 20 via the base portion 62S so as to be movable in the vertical direction relative to the placement surface of the table 20. The second positioning pin 620 is disposed at a distance from the first positioning pin 610 in the pin arrangement direction (front-back direction in FIG. 4) which is a direction parallel to the placement surface of the table 20. The second positioning pin 620 extends in the vertical direction and is supported by the table 20 via the base portion 62S so as to be movable in the vertical direction relative to the placement surface. The second positioning pin 620 is engageable with the second pin receiving portion 30Q so as to allow the pallet 30 to move relative to the second positioning pin 620 in the pin arrangement direction and to restrain the pallet 30 in an adjustment direction (left-right direction in FIG. 4) which is parallel to the placement surface of the table 20 and perpendicular to the pin arrangement direction.

In this embodiment, the second positioning pin 620 has a square tapered pin shape. Specifically, the second positioning pin 620 has a second tip portion 620A including a pair of ridges 620S (FIG. 13) that are spaced apart from each other in the adjustment direction (left-right direction) and extend along the pin arrangement direction (front-rear direction). On the other hand, the second pin receiving portion 30Q has a pair of inclined surfaces 30Q1 (FIG. 15) that are spaced apart from each other in the adjustment direction, extend in the pin arrangement direction, and incline upward to approach each other, and can abut against the pair of ridges 620S. In this embodiment, a pair of metal flat plates are fixed to the lower surface of the pallet 30 to form a pair of inclined surfaces 30Q1 (FIG. 16). Note that, on the lower surface of the pallet 30, both the front and rear sides of the pair of inclined surfaces 30Q1 (flat plates) are open. That is, the dimensions of the second positioning pin 620 and the second pin receiving portion 30Q in the pin alignment direction are set so that, with the pair of inclined surfaces 30Q1 abutting against the pair of ridges 620S (FIG. 13) and restraining the second pin receiving portion 30Q in the adjustment direction relative to the second positioning pin 620, the second pin receiving portion 30Q can move relative to the second positioning pin 620 in the pin alignment direction.

As a result, when the pallet 30 is transported onto the table 20 as shown in Figures 12 and 16, and the second tip 620A of the second positioning pin 620 shown in Figure 13 engages with the second pin receiving portion 30Q from below, the second pin receiving portion 30Q becomes movable left and right together with the second positioning pin 620, and the second pin receiving portion 30Q becomes movable forward and backward relative to the second positioning pin 620. The vertical movement of the second positioning pin 620 is performed by the hydraulic cylinder 62P (Figure 15).

The base portion 62S is a plate-like member fixed to the upper surface of the table 20 by a number of bolts. A pair of left and right blocks 621 are fixed to the base portion 62S at a distance from each other in the left-right direction. A second positioning pin 620 is disposed between the pair of left and right blocks 621 so as to be movable in the up-down direction. The base portion 62S and the pair of left and right blocks 621 constitute the second support frame of the present invention.

The pair of left and right linear guides 622 and the four linear roller bearings 623 constitute the second linear guide mechanism of the present invention. These members are supported by the second support frame and support the second positioning pin 620 so as to guide the second positioning pin 620 in the up-down direction. Rollers (rolling elements) (not shown) are also housed inside the linear guides 622 and linear roller bearings 623.

The pair of front and rear tension bars 624 are arranged to connect the pair of left and right blocks 621 to each other on both the front and rear sides. In Figures 13 and 14, by tightening each nut 625, a preload can be applied to each block 621 in a direction that brings the blocks 621 closer to each other. In other words, each tension bar 624 and each nut 625 constitute the second preload mechanism of the present invention. The second preload mechanism is attached to the second support frame, and by applying a preload to the second linear guide mechanism, it prevents the second positioning pin 620 from displacing relative to the second support frame in a direction perpendicular to the up-down direction.

Furthermore, the second positioning unit 62 has a scale head 62H, a linear scale 62T, and a linear guide 62X.

The linear scale 62T is fixed to the upper surface of the table 20, and has a scale (not shown) formed along the left-right direction. The scale head 62H is fixed to the base portion 62S, and reads the scale of the linear scale 62T and inputs a signal corresponding to the scale to the control unit 50. The linear guide 62X is fixed to the upper surface of the table 20, and guides the base portion 62S along the left-right direction. Thus, in this embodiment, the base portion 62S of the second positioning portion 62 is supported on the upper surface of the table 20 so that it can move along the left-right direction. At this time, the hydraulic cylinder 62P can also move integrally with the base portion 62S.

The swivel unit 64 is disposed on the upper surface of the table 20 so as to be adjacent to the second positioning unit 62. The swivel unit 64 has a base unit 64S, a motor 640 (adjustment drive unit), a coupling 641, and a ball screw 642. The motor 640 generates a driving force that moves the second positioning pin 620 in the left-right direction via the base unit 62S. The motor 640 receives an adjustment command signal from the drive control unit 500 (movement control unit) and moves the second positioning pin 620 in the left-right direction in response to the adjustment command signal. The coupling 641 is connected to an output shaft (not shown) of the motor 640 and transmits the driving force of the motor 640 to the ball screw 642. The base unit 62S has a female screw portion (not shown) that engages with the ball screw 642, and the base unit 62S can move left-right together with the second positioning pin 620 as the ball screw 642 rotates.

The control unit 50 and the swivel unit 64 constitute the parallelism adjustment unit 102 of the present invention. The parallelism adjustment unit 102 moves the second positioning pin in the adjustment direction while the first positioning pin 610 and the second positioning pin 620 are engaged with the first pin receiving portion 30P and the second pin receiving portion 30Q, respectively, and the clamp unit 63 is switched to the non-clamped state, thereby rotating the pallet 30 around the first positioning pin 610 and adjusting the parallelism of the workpiece W. On the other hand, the swivel command unit 501B of the control unit 50 calculates the amount of movement of the second positioning pin 620 so that the reference surface of the workpiece W is parallel to the front-rear direction (X-axis) according to the measurement result of the parallelism measurement unit 101. Then, the drive control unit 500 inputs the adjustment command signal to the motor 640 according to the amount of movement calculated by the swivel command unit 501B.

Figure 17 is a schematic diagram showing how the pallet 30 is rotated in the machine tool 1 according to this embodiment. Figure 18 is a schematic diagram explaining the amount of rotation of the pallet 30 in the machine tool 1.

As described above, when the first positioning pin 610 and the second positioning pin 620 are engaged with the first pin receiving portion 30P and the second pin receiving portion 30Q from below, and the second positioning pin 620 moves in the left-right direction by the driving force of the motor 640, the pallet 30 can rotate in the direction of the arrow around the first positioning pin 610 (rotation center axis CL) from the position shown by the solid line in FIG. 17 to the position shown by the two-dot chain line. As a result, the parallelism of the workpiece W placed on the pallet 30 can be adjusted so that the reference plane of the workpiece W is parallel to the X-axis of the machine body 100. At this time, the second positioning pin 620 moves linearly along the movement straight line DS in FIG. 18, while the second pin receiving portion 30Q rotates around the first pin receiving portion 30P. The distance L between the first pin receiving portion 30P and the second pin receiving portion 30Q of the pallet 30 does not change, but the distance between the first pin receiving portion 30P (first positioning pin 610) and the second positioning pin 620 on the movement line DS changes to L + ΔL. In order to realize the pivoting movement of the pallet 30 by such linear movement of the second positioning pin 620, as described above, the second positioning pin 620 is movable relative to the second pin receiving portion 30Q in the front-rear direction. The same applies to the pivoting movement of the pallet 30 in the direction opposite to the arrow in FIG. 17.

Next, the procedure for the rotation operation of the pallet 30 in the machine tool 1 will be described in more detail. Figure 19 is a hydraulic circuit diagram in the machine tool 1 according to this embodiment. Figure 20 is a flowchart of the parallelism adjustment operation of the workpiece W in the machine tool 1 according to this embodiment.

The hydraulic circuit shown in FIG. 19 is for vertically moving the first positioning pin 610, the second positioning pin 620, and the six clamp plates 631 of the machine tool 1. The machine tool 1 further includes a first pin drive unit 61M and a second pin drive unit 62M (both pin drive units) and a clamp drive unit 63M. Note that FIG. 19 shows a structure for vertically moving one clamp plate 631 and one first positioning pin 610, but the machine tool 1 includes a plurality of structures shown in FIG. 19 for vertically moving the six clamp plates 631, the first positioning pin 610, and the second positioning pin 620. In this case, a part of the cylinder and the hydraulic circuit described below may be shared. In this embodiment, the machine tool 1 has a hydraulic source P shared by the first pin drive unit 61M, the second pin drive unit 62M, and the clamp drive unit 63M, and a tank T. The hydraulic source P is, for example, a hydraulic pump, and discharges (supplies) hydraulic oil. In addition, in the hydraulic circuit of Figure 19, P and T are also illustrated at various points in the oil passages connecting to the hydraulic source P and tank T.

The first pin drive unit 61M and the second pin drive unit 62M each have a hydraulic cylinder 61P (which has the same structure as the hydraulic cylinder 62P), a positioning solenoid valve 71, a first pressure adjustment valve 73 (pressure adjustment valve), a second pressure adjustment valve 74, a pressure reducing valve 75, and a speed adjustment valve 76.

The first positioning pin 610 and the second positioning pin 620 are supported by the table 20 so that they can move up and down between a positioning position and a non-positioning position. The positioning position is a position where the first positioning pin 610 and the second positioning pin 620 engage with the first pin receiving portion 30P and the second pin receiving portion 30Q, respectively, and the non-positioning position is a position below the positioning position where the first positioning pin 610 and the second positioning pin 620 are detached from the first pin receiving portion 30P and the second pin receiving portion 30Q, respectively.

The hydraulic cylinder 61P (hydraulic cylinder 62P) has a cylinder body and a cylinder rod. A first positioning pin 610 (second positioning pin 620) is connected to the tip of the cylinder rod. Meanwhile, the base end of the cylinder rod has a piston structure, and divides the inside of the cylinder body into a head chamber A and a rod chamber B.

The positioning solenoid valve 71 is disposed between the hydraulic source P and the hydraulic cylinder 61P, and operates to switch the direction of hydraulic oil supply from the hydraulic source P to the hydraulic cylinder 61P and adjust the flow rate of the hydraulic oil. The positioning solenoid valve 71 is connected to the head chamber A and the rod chamber B of the hydraulic cylinder 61P. The positioning solenoid valve 71 has a pair of solenoids (first solenoid 71A and second solenoid 71B), and is held in a neutral position (center position in FIG. 19) when no switching signal is input to both solenoids 71A and 71B, is switched to a first drive position (lower position in FIG. 19) when a switching signal is input to the first solenoid 71A, and is switched to a second drive position (upper position in FIG. 19) when a switching signal is input to the second solenoid 71B. In the neutral position, the positioning solenoid valve 71 blocks the flow of hydraulic oil between the hydraulic cylinder 61P and the hydraulic source P and tank T. In the first drive position, the positioning solenoid valve 71 allows the flow of hydraulic oil between the hydraulic source P and the head chamber A of the hydraulic cylinder 61P, and allows the flow of hydraulic oil between the rod chamber B of the hydraulic cylinder 61P and the tank T. Therefore, the hydraulic oil supplied from the hydraulic source P flows into the head chamber A of the hydraulic cylinder 61P, and the hydraulic oil discharged from the rod chamber B of the hydraulic cylinder 61P is led to the tank T. As a result, the hydraulic cylinder 61P extends, and the first positioning pin 610 moves upward to the positioning position. In the second drive position, the positioning solenoid valve 71 allows the flow of hydraulic oil between the hydraulic source P and the rod chamber B of the hydraulic cylinder 61P, and allows the flow of hydraulic oil between the head chamber A of the hydraulic cylinder 61P and the tank T. As a result, hydraulic oil supplied from the hydraulic source P flows into the rod chamber B of the hydraulic cylinder 61P, and hydraulic oil discharged from the head chamber A of the hydraulic cylinder 61P is led to the tank T. As a result, the hydraulic cylinder 61P contracts, and the first positioning pin 610 moves downward to the non-positioning position. The position of the positioning solenoid valve 71 is switched between the first drive position, the second drive position, and the neutral position by receiving a switching signal from the drive control unit 500 of the control unit 50. The same applies to the vertical movement of the second positioning pin 620 by the hydraulic cylinder 62P.

The first pressure regulating valve 73 discharges a portion of the hydraulic oil into the tank T when the pressure between the head chamber A of the hydraulic cylinder 61P and the positioning solenoid valve 71 exceeds a predetermined pressure.

Similarly, the second pressure regulating valve 74 discharges a portion of the hydraulic oil into the tank T when the pressure between the rod chamber B of the hydraulic cylinder 61P and the positioning solenoid valve 71 exceeds a predetermined pressure.

The pressure reducing valve 75 adjusts the pressure of the hydraulic oil supplied from the hydraulic source P to the positioning solenoid valve 71.

The speed adjustment valve 76 is disposed between the first pressure adjustment valve 73 and the second pressure adjustment valve 74 and the hydraulic cylinder 61P, and adjusts the speed of the hydraulic oil flowing into the hydraulic cylinder 61P. As a result, a large amount of hydraulic oil is suddenly supplied to the hydraulic cylinder 61P, preventing the first positioning pin 610 from suddenly moving up and down.

The clamp drive unit 63M receives a clamp command signal from the drive control unit 500 of the control unit 50, and is capable of moving each clamp plate 631 up and down in response to the clamp command signal. For this reason, the drive control unit 500 (clamp control unit) of the control unit 50 described above inputs the clamp command signal to the clamp drive unit 63M, and switches each clamp plate 631 between the clamp position and the non-clamp position. In addition to the clamp cylinder 632 described above, the clamp drive unit 63M has a pallet clamp solenoid valve 72 and a pressure switch 77.

As described above, the clamp cylinder 632 has a cylinder body and a cylinder rod. The tip of the cylinder rod is connected to the clamp plate 631. Meanwhile, the base end of the cylinder rod has a piston structure, which divides the inside of the cylinder body into a rod chamber C and a head chamber D.

The pallet clamp solenoid valve 72 is disposed between the hydraulic source P and the clamp cylinder 632, and operates to switch the direction of hydraulic oil supply from the hydraulic source P to the clamp cylinder 632 and adjust the flow rate of the hydraulic oil. The pallet clamp solenoid valve 72 is connected to the head chamber D and the rod chamber C of the clamp cylinder 632. The pallet clamp solenoid valve 72 has a pair of solenoids (first solenoid 72A and second solenoid 72B), and is held in a neutral position (center position in FIG. 19) when no switching signal is input to both solenoids 72A and 72B, is switched to a first drive position (lower position in FIG. 19) when a switching signal is input to the first solenoid 72A, and is switched to a second drive position (upper position in FIG. 19) when a switching signal is input to the second solenoid 72B. In the neutral position, the pallet clamp solenoid valve 72 blocks the flow of hydraulic oil between the clamp cylinder 632 and the hydraulic source P and tank T. In the first drive position, the pallet clamp solenoid valve 72 allows the flow of hydraulic oil between the hydraulic source P and the rod chamber C of the clamp cylinder 632, and allows the flow of hydraulic oil between the head chamber D of the clamp cylinder 632 and the tank T. Therefore, the hydraulic oil supplied from the hydraulic source P flows into the rod chamber C of the clamp cylinder 632, and the hydraulic oil discharged from the head chamber D of the clamp cylinder 632 is led to the tank T. As a result, the clamp cylinder 632 contracts, and the clamp plate 631 moves downward to the clamp position. In the second drive position, the pallet clamp solenoid valve 72 allows the flow of hydraulic oil between the hydraulic source P and the head chamber D of the clamp cylinder 632, and allows the flow of hydraulic oil between the rod chamber C of the clamp cylinder 632 and the tank T. As a result, hydraulic oil supplied from the hydraulic source P flows into the head chamber D of the clamp cylinder 632, and hydraulic oil discharged from the rod chamber C of the clamp cylinder 632 is led to the tank T. As a result, the clamp cylinder 632 extends, and the clamp plate 631 moves upward to the non-clamped position. The position of the pallet clamp solenoid valve 72 is switched between the first drive position, the second drive position, and the neutral position by receiving a switching signal from the drive control unit 500 of the control unit 50.

The pressure switch 77 opens when the pressure difference between the tank pressure and the head pressure of the clamp cylinder 632 reaches a predetermined pressure, and discharges a portion of the hydraulic oil supplied to the head chamber of the clamp cylinder 632 into the tank T.

Referring to FIG. 20, when machining work on the workpiece W is started, the workpiece W is placed on the pallet 30, and the pallet 30 is transported from the receiving stand 11 onto the table 20 by the receiving stand cylinder 31 (step S1).

When the pallet 30 is brought onto the table 20, in order to position the pallet 30, the drive control section 500 of the control section 50 inputs a switching signal to the first solenoid 71A to switch the positioning solenoid valve 71 to the first drive position, and the first positioning pin 610 and the second positioning pin 620 rise to the positioning position and engage with the first pin receiving portion 30P and the second pin receiving portion 30Q of the pallet 30, respectively (step S2).

Next, the drive control unit 500 of the control unit 50 controls the receiving cylinder 31, and the tip of the cylinder rod of the receiving cylinder 31 is removed from the pallet 30 (step S3).

Next, when the drive control section 500 of the control section 50 inputs a switching signal to the first solenoid 72A of the pallet clamp solenoid valve 72 to switch the pallet clamp solenoid valve 72 to the first drive position, the clamp plate 631 descends to the clamp position and the pallet 30 is clamped to the table 20 (step S4). At this time, as the pallet 30 descends, a downward force is applied to the first positioning pin 610 and the second positioning pin 620 via the first pin receiving section 30P and the second pin receiving section 30Q, and the pressure in the hydraulic cylinder 61P and the hydraulic cylinder 62P increases, but because some of the hydraulic oil is discharged to the tank T by the first pressure adjustment valve 73, both positioning pins descend while remaining engaged with both pin receiving sections of the pallet 30.

Next, the drive control unit 500 controls the table drive unit 21 to move the table 20 with the pallet 30 clamped backward toward the spindle 40S (machining position) (step S5). Note that the measurement probe 66 is already attached to the spindle 40S.

Next, the parallelism measuring unit 101 measures the parallelism of the workpiece W (step S6). FIG. 21 is a schematic front view showing how the parallelism of the workpiece W is measured in the machine tool 1 according to this embodiment. FIG. 22 is a plan view showing the machining reference surface (reference surface extending in the vertical direction) of the workpiece W in the machine tool 1. In this parallelism measurement, the drive control unit 500 controls the spindle drive unit 60 to bring the measurement probe 66 into contact with the first machining reference surface WA and the second machining reference surface WB of the workpiece W in sequence. The parallelism calculation unit 501A calculates the parallelism of the reference surface of the workpiece W with respect to the X-axis (front-back direction) of the machine tool 1 based on the two measurement signals input from the measurement probe 66.

Next, the rotation command unit 501B determines whether or not a parallelism adjustment operation is required (step S7). Specifically, the rotation command unit 501B determines whether or not the parallelism calculated in step S6 satisfies a preset condition (for example, within ±0.1 degrees). If the condition is satisfied, processing of the workpiece W is started in step S13 described below. On the other hand, if the condition is not satisfied, the spindle 40S is moved to a position where the workpiece W and the measurement probe 66 do not interfere with each other, and then the rotation command unit 501B starts the parallelism adjustment operation.

When the parallelism adjustment operation is started, the drive control unit 500 inputs a switching signal to the second solenoid 72B of the pallet clamp solenoid valve 72 to switch the pallet clamp solenoid valve 72 to the second drive position, raise the clamp plate 631 to the unclamped position, and release the clamp on the pallet 30 (unclamping, step S8). At this time, since the positioning solenoid valve 71 is still set to the first drive position, as the pallet 30 rises, the first positioning pin 610 and the second positioning pin 620 also rise while maintaining the engagement state between the first pin receiving portion 30P and the second pin receiving portion 30Q.

Next, the rotation command unit 501B calculates the amount of movement of the second positioning pin 620 based on the parallelism measurement result in step S6. Then, the drive control unit 500 inputs a command signal to the motor 640 according to the calculated amount of movement, and transmits a rotation force from the motor 640 to the pallet 30 via the ball screw 642, the second positioning pin 620, and the second pin receiving portion 30Q, thereby adjusting the parallelism of the workpiece W (step S9). In this embodiment, the pallet 30 can be moved within a predetermined gap (backlash) provided between the clamp plate 631 (rail 200) and the pallet guide portion 302 in FIG. 6.

Next, the pallet 30 is clamped again to the table 20 as in step S4 (step S10), and the parallelism of the workpiece W is measured again as in step S6 (step S11).

Next, the rotation command unit 501B determines whether the parallelism measurement result satisfies the above condition (step S12), as in step S7, and returns to step S8 if the condition is not satisfied. On the other hand, if the condition is satisfied, the drive control unit 500 controls the table drive unit 21 and the spindle drive unit 60 to perform machining on the workpiece W based on the NC program (Figure 3) (step S13). At this time, the positioning of the pallet 30 by the first positioning pin 610 and the second positioning pin 620 and the clamping by the clamp unit 63 are maintained.

When the processing of the workpiece W is completed, the drive control unit 500 controls the table drive unit 21 to move the pallet 30 to the pallet exchange position (step S14). Furthermore, the drive control unit 500 inputs a switching signal to the second solenoid 72B of the pallet clamp solenoid valve 72 to switch the pallet clamp solenoid valve 72 to the second drive position, raises the clamp plate 631 to the unclamped position, and releases the clamp of the pallet 30 (step S15). At this time, each positioning pin rises while remaining engaged with the pin receiving portion of the pallet 30.

Then, when the drive control unit 500 inputs a switching signal to the second solenoid 71B to switch the positioning solenoid valve 71 to the second drive position, the first positioning pin 610 and the second positioning pin 620 descend to the non-positioning position, and the positioning of the pallet 30 is released (step S16).

Next, the drive control unit 500 causes the receiving cylinder 31 to enter the pallet 30 on the table 20 (step S17) and transports the pallet 30 to the receiving table 11 (step S18). After that, another pallet 30 is again transported from the receiving table 11 to the table 20, and the flow in FIG. 20 is repeated.

In this embodiment, as described above, when the workpiece W is supported on the pallet 30, and the parallelism of the workpiece W is adjusted, a large driving force is required to rotate the pallet 30 when the heavy workpiece W is placed on it. For this reason, a large force acts in the radial direction on the first positioning pin 610 and the second positioning pin 620, which transmit the driving force of the motor 640 of the rotating unit 64 to the pallet 30. At this time, if the positioning pins are displaced or tilted, the pallet 30 may not be able to rotate to the commanded position, and the rotation positioning error may become large.

In this embodiment, in order to solve the problem that is likely to occur when the weight of the workpiece W is large as described above, tension bars 614 and 624 are provided as described above, and by tightening nuts 615 and 625 at both ends, the distance between each pair of blocks 611 and 621 can be adjusted, thereby applying preload (gap adjustment) to the linear guide mechanisms such as the linear guides 612 and 622 and the linear roller bearings 613 and 623.

Figure 23 is a graph showing the relationship between the clearance and displacement of the linear guide mechanism. In order to eliminate the clearance in linear guide devices such as the linear guide and linear roller bearing and increase rigidity, a load (preload) is applied to the internal rolling elements in advance, thereby preventing the displacement of the first positioning pin 610 and the second positioning pin 620. As shown in Figure 23, applying a load to provide a negative clearance (bite) can maintain high rigidity of each positioning pin. As a result, the displacement and tipping of the first positioning pin 610 and the second positioning pin 620 can be prevented when the pallet 30 is rotated.

Furthermore, as described above, if the coupling 641 or ball screw 642 of the rotating unit 64 is twisted or deformed due to the large driving force generated when rotating the pallet 30 supporting the heavy workpiece W, an error may occur between the ideal movement amount of the second positioning pin 620 based on the rotation amount of the motor 640 in response to the command signal and the actual movement amount. Therefore, in this embodiment, in order to reduce the error between the movement amount of the second positioning pin 620 in response to the command signal and the actual movement amount, the scale head 62H reads the scale of the linear scale 62T and feeds back the result to the control unit 50, so that the actual movement amount of the second positioning pin 620 can be measured and corrected while the second positioning pin 620 is accurately moved to the target position.

As described above, in this embodiment, after the pallet 30 on which the workpiece W is placed is carried into the machine tool 1, the first positioning pin 610 and the second positioning pin 620 rise to engage with the first pin receiving portion 30P and the second pin receiving portion 30Q of the pallet 30, thereby positioning the pallet 30 with respect to the table 20. Then, after the pallet 30 is lowered and clamped by the clamping unit 63, the parallelism of the workpiece W with respect to the coordinate axis of the machine tool 1 is measured by the measuring probe 66 attached to the spindle 40S, and if the deviation in parallelism is within a predetermined value, processing can be started as is. On the other hand, if the deviation in parallelism exceeds a predetermined value, the clamping by the clamping unit 63 is released to raise the pallet 30, and the second positioning pin 620 is moved by the rotating unit 64 while maintaining the engagement of the first positioning pin 610 and the second positioning pin 620 with the first pin receiving portion 30P and the second pin receiving portion 30Q of the pallet 30, thereby adjusting the parallelism of the workpiece W. Then, the pallet 30 is clamped again by the clamp unit 63, the parallelism is measured again, and once it has been confirmed that the deviation in parallelism falls within a predetermined value, processing can begin.

In particular, the parallelism of the pallet 30 is adjusted with the first positioning pin 610 and the second positioning pin 620 engaged with the first pin receiving portion 30P and the second pin receiving portion 30Q, respectively. Therefore, the pallet 30 is allowed to rotate around the first pin receiving portion 30P (rotation center axis CL) while the pallet 30 is restricted from moving in other directions along the mounting surface of the table 20. This prevents the pallet 30 from moving in a direction different from the target direction, and the parallelism of the workpiece W can be adjusted with high precision by the rotational movement. In addition, the second positioning pin 620 engages with the second pin receiving portion 30Q so as to allow the pallet 30 to move relative to the second positioning pin 620 in the pin arrangement direction and to restrain the pallet 30 in the adjustment direction, so that the pallet 30 can be stably rotated in response to the linear movement of the second positioning pin 620 along the adjustment direction by the parallelism adjustment unit 102.

In addition, in this embodiment, in a plan view, the first positioning portion 61, the second positioning portion 62, the clamp portion 63, and the rotating portion 64 are arranged within the dimensions of the table 20, and the first pin receiving portion 30P and the second pin receiving portion 30Q are also arranged to fit within the dimensions of the pallet 30. Therefore, the size of the machine tool 1 can be made compact compared to when the mechanism and drive source for adjusting the parallelism of the pallet 30 are provided outside the table 20.

In addition, in this embodiment, the first pin receiving portion 30P that restricts the movement of the pallet 30 and the second pin receiving portion 30Q to which the driving force for rotating the pallet 30 is input are arranged in a limited area on the inside (interior) of the pallet 30 in a plan view. Therefore, compared to when the outer surface of the pallet 30 is pressed for a rotating operation, slippage or misalignment of the pallet 30 is less likely to occur, and the parallelism of the workpiece W can be adjusted with high precision.

In addition, in this embodiment, the parallelism adjustment unit 102 has a motor 640, a rotation command unit 501B, and a drive control unit 500, so that the parallelism of the workpiece W can be automatically adjusted and processing of the workpiece W can be started according to the current parallelism measurement result measured by the parallelism measurement unit 101.

In addition, in this embodiment, the first positioning pin 610 having a conical first tip engages with the first pin receiving portion 30P, so that the movement of the pallet 30 can be stably restricted to a rotational movement around the first positioning pin 610. In addition, a pair of ridges of the second positioning pin 620 abut against a pair of inclined surfaces of the second pin receiving portion 30Q, respectively, so that the second positioning pin 620 restrains the pallet 30 in the adjustment direction while the pallet 30 can move relatively in the pin arrangement direction, and the rotational movement of the pallet 30 can be stably realized.

In addition, in this embodiment, the first pin drive unit 61M and the second pin drive unit 62M are capable of lowering the first positioning pin 610 and the second positioning pin 620, respectively, so that the first positioning pin 610 and the second positioning pin 620 remain engaged with the first pin receiving portion 30P and the second pin receiving portion 30Q, respectively, as the drive control unit 500 switches each clamp plate 631 from the non-clamped position to the clamped position. This prevents the pallet 30 from moving in a direction parallel to the placement surface during the clamping operation, and allows the relative position of the pallet 30 to the table 20 to be stably maintained.

In particular, in this embodiment, the hydraulic cylinder 61P and the hydraulic cylinder 62P each have a plurality of hydraulic chambers (head chamber A, rod chamber B) therein, and the hydraulic oil supplied from the hydraulic source P is received in one of the plurality of hydraulic chambers, and the hydraulic oil is discharged from the other hydraulic chambers, thereby moving the first positioning pin 610 and the second positioning pin 620 in the vertical direction. In addition, the positioning solenoid valve 71 (control valve) is interposed between the hydraulic source P and each of the hydraulic cylinders, and switches the supply destination of the hydraulic oil supplied from the hydraulic source among the plurality of hydraulic chambers, thereby switching the first positioning pin 610 and the second positioning pin 620 between the positioning position and the non-positioning position. Furthermore, the first pressure regulating valve 73 is interposed between the positioning solenoid valve 71 and each of the hydraulic cylinders, and in response to the force that the first positioning pin 610 and the second positioning pin 620 receive from the pallet 30 when the drive control unit 500 switches the clamp plate 631 from the non-clamped position to the clamped position with the first positioning pin 610 and the second positioning pin 620 set to the positioning position, the first pressure regulating valve 73 is capable of discharging a portion of the hydraulic oil between the positioning solenoid valve 71 and each of the hydraulic cylinders. With this configuration, compared to the case where the lowering operation of the first positioning pin 610 and the second positioning pin 620 is individually controlled in response to the lowering of the clamp plate 631, the occurrence of a gap between each positioning pin and each pin receiving portion is suppressed, and the pallet 30 can be clamped while stably maintaining the relative position of the pallet 30 to the table 20.

In addition, in this embodiment, the first positioning part 61 has a first preload mechanism consisting of a tension bar 614 and a nut 615, which prevents the first positioning pin 610 from being displaced or falling during processing of the workpiece W or during rotation of the pallet 30, and the position of the pallet 30 can be stably maintained.

Similarly, because the second positioning portion 62 has a second preload mechanism consisting of a tension bar 624 and a nut 625, the second positioning pin 620 is prevented from being displaced or falling during machining of the workpiece W or during rotation of the pallet 30, and the position of the pallet 30 can be stably maintained. In particular, during rotation, the movement direction of the second positioning pin 620 differs from the movement direction of the second pin receiving portion 30Q of the pallet 30, so that the second positioning pin 620 is likely to be subjected to a large load. Even in such a case, the above-mentioned preload mechanism allows the movement of the second positioning pin 620 and the rotation of the pallet 30 to be stably achieved.

Furthermore, in this embodiment, the base portion 62S of the second positioning unit 62 is supported by the table 20 so as to be movable in the adjustment direction, and the parallelism adjustment unit 102 moves the second positioning pin 620 by moving the base portion 62S in the adjustment direction, thereby adjusting the parallelism of the workpiece W. Therefore, the pallet 30 can be rotated while maintaining a high rigidity of the second positioning unit 62, compared to the case where the second positioning pin 620 is moved alone.

Furthermore, in this embodiment, the second positioning unit 62 is provided with a linear scale 62T and a scale head 62H, so that the amount of movement of the second positioning pin 620 can be accurately detected according to the reading result of the scale head 62H, and this can be fed back to the command signal by the drive control unit 500.

Next, a second embodiment of the present invention will be described. This embodiment differs from the first embodiment in the structure for applying preload to the first positioning pin 610 and the second positioning pin 620, and this difference will be described. Figures 24 and 25 are a perspective view and a plan view of the first positioning unit 61 of the machine tool 1 according to this embodiment. Figures 26 and 27 are a perspective view and a plan view of the second positioning unit 62 and the swivel unit 64 of the machine tool 1 according to this embodiment.

In this embodiment, instead of the tension bar 614 and nut 615 of the first embodiment, the first positioning part 61 has a pair of front and rear brackets 616 and a pair of front and rear adjustment plates 617 (Figures 24 and 25).

Each bracket 616 is arranged to sandwich a pair of left and right blocks 611 from the front and rear, and both ends of each are fixed to the pair of left and right blocks 611 with bolts. Meanwhile, the pair of front and rear adjustment plates 617 are inserted into the gap between the block 611 on the left side (see the direction indication in Figure 25) and each bracket 616. At this time, the dimensions of the adjustment plate 617 are set slightly larger than the gap. As a result, as in the first embodiment, it is possible to apply a preload to the linear guide mechanism such as the linear guide 612 and the linear roller bearing 613, and the rigidity of the first positioning pin 610 can be increased.

Similarly, instead of the tension bar 624 and nut 625 of the first embodiment, the second positioning part 62 has a pair of front and rear brackets 626 and a pair of front and rear adjustment plates 627 (Figures 26 and 27), which increases the rigidity of the second positioning pin 620.

The above describes the machine tools according to the various embodiments of the present invention, but the present invention is not limited to these, and the following modifications are possible.

(1) In the above embodiment, the machine tool 1 is described as a gate-type machine tool, but the present invention is not limited to this and may be a machine tool having a different structure.

(2) In the above embodiment, the table drive unit 21 that moves the table 20 between the machining area (rear machining area P1, front machining area P2) and the pallet exchange position P3 is described as being composed of the motor 22 and ball screw 23, but the present invention is not limited to this. The table drive unit may include multiple motors and ball screws, or may have a drive transmission structure other than a ball screw structure. In addition, a pallet exchange device may be installed in the rear machining area.

(3) In addition, in the above embodiment, the workpiece reference surface is measured to measure the parallelism of the workpiece W. However, other measurement methods may be used, such as providing a reference hole in the workpiece W and measuring the parallelism of the workpiece W based on the center point of the reference hole. In either case, information corresponding to the reference surface of the workpiece W is obtained in some way and compared with the coordinate axes on the machine body 100 side, thereby measuring the parallelism of the workpiece W.

1 Machine tool 10 Bed 11 Support 100 Machine body 101 Parallelism measuring section 102 Parallelism adjusting section 20 Table 200 Rail 201 Pallet support section 21 Table driving section 30 Pallet 301 Pallet recess 302 Pallet guide section (pallet engagement section)
303 Roller 303A Roller lower end 304 Side roller 305 Space 30P First pin receiving portion 30Q Second pin receiving portion 30Q1 Inclined surface 31 Support cylinder 35 Pallet moving portion 40 Frame 40A Column 40B Cross rail 40S Main shaft (tool support portion)
41 Processing unit 42 Saddle 48 Operation unit 50 Control unit 500 Drive control unit (movement control unit, clamp control unit)
501 Numerical control unit 501A Parallelism calculation unit 501B Turn command unit (movement amount calculation unit)
502 Memory section 60 Spindle drive section 61 First positioning section (first positioning unit)
610: First positioning pin 610A: First tip portion 611: Block (first support frame)
612 Linear guide (first linear guide mechanism)
613 Linear roller bearing (first linear guide mechanism)
614 Tension bar (first preload mechanism)
615 Nut (first preload mechanism)
616 Bracket (first preload mechanism)
617 Adjustment plate (first preload mechanism)
61M First pin drive unit (pin drive unit)
61P Hydraulic cylinder 61S Base part (first support frame)
62 Second positioning portion (second positioning unit)
620: Second positioning pin 620A: Second tip portion 621: Block (second support frame)
622 Linear guide (second linear guide mechanism)
623 Linear roller bearing (second linear guide mechanism)
624 Tension bar (second preload mechanism)
625 Nut (Second preload mechanism)
626 Bracket (second preload mechanism)
627 Adjustment plate (second preload mechanism)
62H Scale head 62M Second pin drive unit (pin drive unit)
62P Hydraulic cylinder 62S Base part (second support frame)
62T Linear scale 62X Linear guide 63 Clamp section 631 Clamp plate (clamp member)
632 Clamp cylinder 63M Clamp drive unit 64 Rotation unit 640 Motor (adjustment drive unit)
65 Check sensor 66 Measurement probe 71 Positioning solenoid valve (control valve)
72 Pallet clamp solenoid valve 73 First pressure regulating valve (pressure regulating valve)
74 Second pressure adjustment valve 75 Pressure reducing valve 76 Speed adjustment valve 77 Pressure switch CL Swivel central axis DS Movement straight line P Hydraulic source P1 Machining rear end position P2 Machining front end position P3 Pallet exchange position W Workpiece WA First machining reference plane WB Second machining reference plane

Claims (9)

A machine body having a coordinate axis perpendicular to the up-down direction;
a table having an upwardly facing placement surface and supported by the machine body;
a pallet that is detachably placed on the placement surface of the table, the pallet having a pallet upper surface portion capable of supporting a workpiece having a reference surface extending in a vertical direction, a pallet lower surface portion disposed opposite the placement surface on the opposite side to the pallet upper surface portion, a first pin receiving portion disposed on the pallet lower surface portion, and a second pin receiving portion disposed on the pallet lower surface portion at a distance from the first pin receiving portion in a direction parallel to the placement surface;
a tool support section supported by the machine body and capable of supporting a tool for machining the workpiece;
A parallelism measuring unit capable of measuring parallelism, which is a relative angle of the reference surface of the workpiece with respect to the coordinate axis in a plan view;
a first positioning pin extending in a vertical direction and supported on the table so as to be movable in the vertical direction relative to the placement surface, the first positioning pin being engageable with the first pin receiving portion so that the pallet can rotate relative to the table around the first positioning pin;
a second positioning pin that is disposed at a distance from the first positioning pin in a pin arrangement direction that is a direction parallel to the placement surface, extends in a vertical direction, and is supported on the table so as to be movable vertically relative to the placement surface, the second positioning pin being engageable with the second pin receiving portion so as to allow the pallet to move relative to the second positioning pin in the pin arrangement direction and to restrain the pallet in an adjustment direction that is parallel to the placement surface and perpendicular to the pin arrangement direction;
a clamp unit arranged on the table and switchable between a clamped state and an unclamped state, the clamped state being a state that prevents the pallet from moving relative to the table in a direction parallel to the placement surface and allows the tool to machine the workpiece, and the unclamped state being a state that allows the pallet to move relative to the table;
a parallelism adjustment unit that is capable of adjusting the parallelism of the workpiece by moving the second positioning pin in the adjustment direction while the first positioning pin and the second positioning pin are engaged with the first pin receiving portion and the second pin receiving portion, respectively, and the clamp unit is switched to the non-clamped state, thereby rotating the pallet around the first positioning pin;
A machine tool comprising: The parallelism adjustment unit is
an adjustment drive unit that receives an adjustment command signal and is capable of moving the second positioning pin in the adjustment direction in response to the adjustment command signal;
a movement amount calculation unit that calculates a movement amount of the second positioning pin according to a measurement result of the parallelism measurement unit so that the reference surface of the workpiece is parallel to the coordinate axis;
a movement control unit that inputs the adjustment command signal to the adjustment drive unit in response to the movement amount calculated by the movement amount calculation unit;
The machine tool according to claim 1 , The first positioning pin has a first conical tip,
the first pin receiving portion has a conical inner peripheral surface capable of contacting the first tip portion along a circumferential direction,
the second positioning pin has a second tip portion including a pair of ridge lines that are spaced apart from each other in the adjustment direction and each extend along the pin arrangement direction,
the second pin receiving portion has a pair of inclined surfaces that are disposed at an interval from each other in the adjustment direction, extend in the pin arrangement direction, and are inclined upward so as to approach each other, and are capable of abutting against the pair of ridge lines, respectively;
3. The machine tool according to claim 1, wherein the dimensions of the second positioning pin and the second pin receiving portion in the pin alignment direction are set so that the second pin receiving portion can move relative to the second positioning pin in the pin alignment direction while the pair of inclined surfaces abut against the pair of ridge lines, respectively, thereby restricting relative movement of the second pin receiving portion relative to the second positioning pin in the adjustment direction. The pallet has at least one pallet engagement portion disposed on the pallet lower surface portion,
The clamp portion is
at least one clamp member supported on the table so as to be movable vertically relative to the placement surface between a clamp position and an unclamping position, the clamp position being a position where the at least one clamp member presses the at least one pallet engaging portion downward to restrain the pallet, thereby placing the clamp portion in the clamped state, and the unclamping position being a position above the clamp position where the at least one clamp member moves away from the at least one pallet engaging portion to release the restraint of the pallet, thereby placing the clamp portion in the unclamping state; and
a clamp driver that receives a clamp command signal and is capable of moving the at least one clamp member in a vertical direction in response to the clamp command signal;
a clamp control unit that inputs the clamp command signal to the clamp drive unit and switches the at least one clamp member between the clamp position and the unclamped position;
having
The machine tool according to any one of claims 1 to 3, further comprising a pin drive unit capable of lowering the first positioning pin and the second positioning pin so as to maintain the first positioning pin and the second positioning pin engaged with the first pin receiving portion and the second pin receiving portion, respectively, as the clamp control unit switches the at least one clamp member from the unclamped position to the clamped position. the first positioning pin and the second positioning pin are each supported on the table so as to be vertically movable between a positioning position and a non-positioning position, the positioning position is a position where the first positioning pin and the second positioning pin engage with the first pin receiving portion and the second pin receiving portion, respectively, and the non-positioning position is a position below the positioning position where the first positioning pin and the second positioning pin are detached from the first pin receiving portion and the second pin receiving portion, respectively;
The pin drive unit is
a hydraulic source that supplies hydraulic oil; and at least one hydraulic cylinder that has a plurality of hydraulic chambers therein and is capable of moving the first positioning pin and the second positioning pin in the up and down direction by receiving the hydraulic oil supplied from the hydraulic source into one of the plurality of hydraulic chambers and discharging the hydraulic oil from the other hydraulic chambers of the plurality of hydraulic chambers.
at least one control valve interposed between the hydraulic power source and the at least one hydraulic cylinder, for switching a supply destination of the hydraulic oil supplied from the hydraulic power source among the plurality of hydraulic chambers to switch the first positioning pin and the second positioning pin between the positioning position and the non-positioning position;
a pressure regulating valve interposed between the control valve and the at least one hydraulic cylinder, the pressure regulating valve being capable of discharging a portion of the hydraulic oil between the control valve and the at least one hydraulic cylinder in response to a force applied to the first positioning pin and the second positioning pin from the pallet when the clamp control unit switches the at least one clamp member from the non-clamping position to the clamping position with the first positioning pin and the second positioning pin disposed at the positioning position;
The machine tool according to claim 4 , further comprising: A first positioning unit supporting the first positioning pin is further provided,
The first positioning unit is
A first support frame supported by the table;
a first linear motion guide mechanism that is attached to the first support frame and supports the first positioning pin so as to guide the first positioning pin in a vertical direction;
a first preload mechanism that is attached to the first support frame and applies a preload to the first linear motion guide mechanism to prevent the first positioning pin from displacing relative to the first support frame in a direction perpendicular to a vertical direction;
6. A machine tool according to claim 1, further comprising: Further comprising a second positioning unit supporting the second positioning pin,
The second positioning unit is
A second support frame supported by the table;
a second linear motion guide mechanism that is attached to the second support frame and supports the second positioning pin so as to guide the second positioning pin in a vertical direction;
a second preload mechanism that is attached to the second support frame and applies a preload to the second linear motion guide mechanism to prevent the second positioning pin from displacing relative to the second support frame in a direction perpendicular to a vertical direction;
7. A machine tool according to claim 1, further comprising: the second support frame is supported by the table so as to be movable in the adjustment direction;
The machine tool according to claim 7 , wherein the parallelism adjustment section adjusts the parallelism of the workpiece by moving the second support frame of the second positioning unit in the adjustment direction to move the second positioning pin. a linear scale attached to one of the table and the second support frame;
a scale head that is attached to the other of the table and the second support frame and is capable of reading the linear scale;
The machine tool of claim 8 further comprising:

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