Method for processing workpiece and machine tool

Abstract

To perform full processing of a workpiece by resolving problems such as high costs and large installation space.SOLUTION: A workpiece W is gripped by a workpiece gripping device 16 such that its axis is oriented in the second axial direction that is orthogonal to the axial direction (first axial direction) of a workpiece spindle 3. By relatively moving a tool spindle 2 and the workpiece gripping device 16, workpiece end processing such as center hole processing of the workpiece W is performed. Subsequently, a workpiece hand 13 is attached to the tool spindle 2. By relatively moving the tool spindle 2 and the workpiece gripping device 16 in a state where the axis of the workpiece W is oriented in the second axial direction, the workpiece W is delivered from the workpiece gripping device 16 to the workpiece hand 13. Next, the tool spindle 2 is swiveled such that the axis of the workpiece W is oriented in the first axial direction, and the workpiece W is conveyed to a position where it can be delivered from the tool spindle 2 to the workpiece spindle 3. Finally, the workpiece W is gripped by the workpiece spindle 3, and processing such as cutting processing is performed.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for machining a workpiece by a machine tool and a machine tool for carrying out the method. [Background technology]

[0002] Conventionally, when machining a shaft workpiece, the center holes at both ends and the end faces are machined using a centering machine or horizontal machining center, and then the shaft outer diameter turning and milling are performed in two separate processes using a different machine tool.

[0003] According to the above-mentioned general machining method, machining of a shaft workpiece is divided into processes for hole-cutting at both ends, machining of both ends, turning of the outer diameter, and milling, and a separate machine tool is required for each process, resulting in problems of high costs and requiring a large installation space for the machine tools.

[0004] Therefore, Patent Document 1 proposes using an NC lathe having two opposing headstocks to perform all machining including centering of a workpiece.

[0005] The system disclosed in Patent Document 1 uses two opposing headstocks, each of which is provided with a center mounting / dismounting device, which means that problems such as high costs and a large installation space for the machine tool are not fully resolved. In addition, there are problems such as the structure being complicated because a mechanism for inserting and removing a tool for center hole machining is provided in the work spindle, and the tool condition being difficult to check because the tool is inside the spindle, and even if one tries to remove the tool to check it, it is time-consuming to remove it. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 3-86402 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in consideration of the above-mentioned problems associated with the conventional technology, and has as its object to provide a workpiece machining method and machine tool which solves the problems of high costs and large installation space required when using a conventional multi-tasking machine as the machine tool for all machining operations including centering of a workpiece using a single machine tool, and which does not cause any new problems in the machining process. [Means for solving the problem]

[0008] The method for machining a workpiece of the present invention is a method for machining a workpiece using a machine tool equipped with a tool spindle capable of changing tools and having a swivel function, a first workpiece spindle for rotatably supporting a workpiece, and a workpiece gripping device for gripping the workpiece in a machining space, the method comprising the steps of: gripping the workpiece with the workpiece gripping device so that its axis faces a second axis direction that is perpendicular to or inclined from a first axis direction that is the axial direction of the first workpiece spindle; and, with a machining tool attached to the tool spindle, moving the tool spindle and the workpiece gripping device relatively to machine a center hole of the workpiece and / or machine an end portion of the workpiece including its peripheral end face; and then, as a step B, A work hand for gripping and releasing the workpiece is attached to the tool spindle, and the workpiece is transferred from the workpiece gripping device to the workpiece hand by moving the tool spindle and the workpiece gripping device relatively with the axis of the workpiece facing the second axis direction. Next, in step C, the tool spindle is rotated so that the axis of the workpiece faces the first axis direction, and the workpiece is transported to a position where it can be transferred from the tool spindle to the first workpiece spindle. Next, in step D, the workpiece is gripped by the first workpiece spindle and any one of cutting, thermal, grinding and polishing processes is performed.

[0009] The tool spindle and the work gripping device are each capable of appropriate movement (linear movement in the three axial directions of up / down, front / back, and left / right, and rotational movement around each axis, or some of these movements), and when moving the tool spindle and the work gripping device relative to each other, either one or both may be moved.

[0010] In the workpiece machining method of this invention, the machine tool can be one equipped with a tool spindle capable of tool replacement and a swivel function, and a workpiece spindle that rotatably supports the workpiece (a machine tool called a multi-tasking machine). That is, by using the same tool spindle and workpiece spindle as the basic configuration as before, and providing a workpiece gripping device within the machine tool as an existing device or a new structure, all of the workpiece machining that was previously performed using multiple machine tools can be performed using a single machine tool.

[0011] In a machine tool, for example, a first work spindle is provided in a fixed state, and a direction coinciding with the axis of the first work spindle is defined as a first axis direction, and a direction perpendicular to or inclined to the first axis direction is defined as a second axis direction, and the tool spindle is capable of linear movement (linear movement approaching or moving away from the first work spindle) while maintaining its axis facing the second axis direction, and of rotating movement to a state in which its axis is parallel to the axis of the first work spindle (a state in which the axis of the work coincides with the first axis direction). The work gripping device may be provided fixedly or movably within the machine tool.

[0012] For example, the machine tool is equipped with an ATC (automatic tool changer), and a processing tool for processing a workpiece or a work hand for gripping the workpiece can be arbitrarily replaced at the tip of the tool spindle, the work gripping device is attached to a turret that is rotatably attached to the tool rest and has a function of gripping an intermediate portion of the workpiece, and the work hand can grip the intermediate portion of the workpiece without interfering with the work gripping device in a state in which the workpiece axis faces the first axis direction. Note that the tool spindle may be one that performs tool replacement by rotating the turret.

[0013] In the workpiece machining method of the present invention, it is preferable that the machine tool further includes a tailstock or a second workpiece spindle opposite the first workpiece spindle, and that the workpiece gripping device is attached to a rotatable turret, and in step A, after workpiece end machining is performed on one end of the workpiece, the turret is rotated to flip the workpiece held by the workpiece gripping device by 180 degrees and then the workpiece end machining is performed on the other end of the workpiece, and after step B, both ends of the workpiece are supported by the first workpiece spindle and the tailstock or the second workpiece spindle.

[0014] In the workpiece machining method of the present invention, if only one end of the workpiece needs to be machined, there is no need to rotate the workpiece 180°, so the workpiece gripping device may be provided on another structure in the machine tool other than the turret. Also, although steps A to D may be performed on a machine tool that does not have a tailstock or second workpiece spindle, a machine tool that has a tailstock or second workpiece spindle is more preferable when performing any of cutting, thermal, grinding, and polishing on the workpiece, since it is possible to support the workpiece from both ends.

[0015] In the workpiece machining method of the present invention, it is preferable that a temporary table for temporarily placing the workpiece is provided inside the machine tool, and in step B, a step is performed of placing the workpiece held by the workpiece hand attached to the tool spindle on the temporary table.

[0016] Although the temporary placement table is not essential when transferring the work from the work gripping device to the work hand, the temporary placement table facilitates the transfer of the work from the work gripping device to the work hand. The temporary placement table may be attached to a turret provided on a tool rest (movable body), may be fixed to a structure in the machining chamber, or may be provided on a movable body in the machining chamber, for example.

[0017] In the workpiece machining method of the present invention, it is preferable that the temporary placement table is provided on a movable body within a machining chamber of the machine tool. The movable body may be, for example, a turret that moves integrally with the tool rest, but is not limited to this.

[0018] The machine tool of the present invention carries out the above-mentioned workpiece machining method (all workpiece machining). Effect of the Invention

[0019] According to the workpiece machining method of this invention, it is possible to use only one conventional machine tool to perform all the machining of the workpiece, which was previously performed using multiple machine tools. This makes it possible to reduce the cost of machine tool equipment and save space required for machine tool installation. Furthermore, by providing a workpiece gripping device to a turret or the like that is conventionally equipped on a machine tool, and using the turret's rotation function to flip the workpiece, it is possible to perform all the machining of the workpiece at low cost. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram showing a first embodiment of a workpiece machining method and a machine tool according to the present invention, illustrating a state in which step A (machining an end portion of a workpiece) is being performed. [Diagram 2] This shows the state in which the first half of process B (transfer of the workpiece between the lower tool rest and the tool spindle) is being performed. [Diagram 3] This shows the state in which the latter half of process B (transfer of the workpiece between the lower tool post and the tool spindle) is being performed. [Figure 4] 13 shows the state in which process C (transporting the workpiece to the workpiece spindle) is being performed. [Diagram 5] The state in which process D (eg, external diameter turning of the workpiece) is being performed is shown. [Figure 6] This shows the workpiece unloading state after the processing is completed. [Figure 7] FIG. 2 is a diagram showing a second embodiment of a workpiece machining method and a machine tool according to the present invention, showing a state corresponding to FIG. 1 of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the left and right and the top and bottom of FIG.

[0022] The machine tool (1) is known as a multi-tasking machine, and as shown in FIG. 1, is equipped with a tool spindle (2) that interchangeably holds several types of tools (11), (12), (13), (14), and (15) at its tip, a work spindle (first work spindle) (3) that rotatably supports a workpiece (W) in the latter process, a tailstock (5) arranged opposite the work spindle (3), a lower tool rest (7) equipped with a turret (8), and an NC control device (not shown).

[0023] The tools (11), (12), (13), (14), and (15) attached to the tool spindle (2) can be changed as necessary by an automatic tool changer (ATC) (not shown). In FIG. 1, a centering tool (11) is attached to the tool spindle (2).

[0024] The work spindle (3) has a chuck (6) that holds the left end of the workpiece (W). The axis of the work spindle (3) extends in the left-right direction. Hereinafter, the axial direction of the work spindle (3) will be referred to as the first axial direction.

[0025] In FIG. 1, a centering tool (11) is attached to the tool spindle (2) with its axis facing up and down perpendicular to the first axis direction, and the tool spindle (2) is capable of linear movement along the direction of this axis (hereinafter referred to as the second axis direction) and linear movement in a direction perpendicular to the second axis direction, as well as rotation about an axis extending perpendicular to the plane of FIG. 1.

[0026] The tailstock (5) has an axis that coincides with the first axis direction, and is movable in the left-right direction (approaching or moving away from the work spindle (3)).

[0027] The lower tool rest (7) is movable in the left-right direction along an axis parallel to the first axis, in the up-down direction perpendicular to the first axis, and in a diagonal direction by synchronous control. The turret (8) is rotatable around the axis of the lower tool rest (7).

[0028] A plurality of devices and tools 16, 17, and 18 are arranged on the turret 8, and the rotation position of the turret 8 can be determined to change the devices and tools 16, 17, and 18 to be used as needed. As one of the devices and tools 16, 17, and 18, the turret 8 is provided with a workpiece gripping device 16 that grips a workpiece W in the machining space, and Fig. 1 shows the workpiece gripping device 16 that grips the workpiece W with its axis facing up and down (a direction perpendicular to the first axis direction).

[0029] The machine tool (1) of this embodiment is configured so that it can perform all machining operations, including centering of a workpiece (W), by itself.

[0030] In this embodiment, the tools attached to the tool spindle (2) include, in addition to the centering tool (11) attached to the tool spindle (2) in FIG. 1, a deep hole machining tool (12) (shown in FIG. 1) used after centering, a pneumatic work hand (13) used in FIGS. 2 to 4, a turning tool (14) used in FIGS. 5 to 6, and an end mill tool (15) (shown in FIG. 5) used after turning with the turning tool (14).

[0031] In this embodiment, the devices and tools (16), (17), and (18) attached to the turret (8) include the workpiece gripping device (16) used in Figures 1 to 3, the temporary placement table (17) used in Figures 4 and 6, and the turning tool (18) used in Figure 5.

[0032] The machining method according to the present invention using the above machine tool (1) is carried out as follows.

[0033] First, as shown in Fig. 1, in the first step (step A), the workpiece (W) is gripped by the workpiece gripping device (16) attached to the lower tool rest (7) so that its axis is perpendicular to the first axis direction (it may be gripped so that it is inclined relative to the perpendicular direction), and a processing tool (11) is attached to the tool spindle (2), and the tool spindle (2) and the workpiece gripping device (16) are moved relatively to perform a predetermined processing on the workpiece (W). The workpiece gripping device (16) is of a hydraulic type with a strong clamping force, and grips the middle part of the workpiece (W) with a pair of upper and lower arms (16a) and (16b).

[0034] The machining in step A involves machining the center hole of the workpiece (W) using a centering machining tool (11) or machining of the surrounding area including the end face (such as external diameter machining of the end portion), and machining the center hole of the workpiece (W) using a deep hole machining tool (12).

[0035] In process A, by setting the turret index to 180°, the workpiece (W) can be held upside down by the workpiece holding device (16), and centering processing and external diameter processing of both ends of the workpiece (W) can be performed.

[0036] 2 and 3, in the second step (step B), the tool spindle (2) is moved upward, and the lower tool rest (7) is moved to the right while the workpiece (W) is held by the workpiece gripping device (16). Then, a workpiece hand (13) for gripping and releasing the workpiece (W) is attached to the tool spindle (2). The workpiece hand (13) is of a pneumatic type, and its tip (13a) grips the center of the workpiece (W) at the intermediate position between a pair of upper and lower arms (16a) and (16b) of the workpiece gripping device (16). The state in which the workpiece (W) is gripped by both the workpiece hand (13) and the workpiece gripping device (16) is shown in FIG. 2.

[0037] By moving the tool spindle (2) leftward and upward from the state shown in Fig. 2, the workpiece (W) held by the workpiece gripping device (16) can be transferred to the workpiece hand (13) (this state is shown in Fig. 3). In Fig. 3, the tool spindle (2) has been moved to a position where it does not interfere with the workpiece (W) or structures within the machine tool (1) when it rotates.

[0038] 4, in the third step (step C), first, the lower tool rest (7) is moved leftward and the turret (8) is rotated to index the workpiece (W) so that it can be placed on the temporary table (17), then the tool spindle (2) is rotated so that the axis of the workpiece (W) coincides with the first axis direction to change the attitude of the workpiece (W), and further, the tool spindle (2) is moved leftward and downward to place the workpiece (W) on the temporary table (17). As a result, the workpiece (W) is transported to a position where it can be handed over to the workpiece spindle (3).

[0039] Next, in the fourth step (step D), as shown in Fig. 5, the tailstock (5) is moved leftward and the workpiece (W) is gripped from the left and right end faces by the chuck (6) of the workpiece spindle (3) and the tailstock (5). This allows the workpiece (W) to be subjected to any one or more of the following processes: cutting, thermal processing, grinding, and polishing.

[0040] In Fig. 5, a turning tool 14 is attached to the tool spindle 2, and the turret 8 is also rotated to a position where a turning tool 18 is used, so that the outer diameter of the workpiece W can be cut from both above and below. After this, the turning tool 14 of the tool spindle 2 can be replaced with, for example, an end mill tool 15 to perform milling (cutting processes other than turning, such as machining of irregular outer periphery shapes), and various other processes can be performed as necessary by using, for example, drills or various other tools not shown.

[0041] When the machining is completed, the turret (8) of the lower tool rest (7) is rotated, the turning tool (18) is replaced with the temporary placement table (17), and the workpiece (W) for which machining has been completed can be removed (workpiece unloading is performed).

[0042] According to the above-mentioned method for machining a workpiece, all machining of the workpiece (W) can be performed by a single machine tool (1), which reduces the cost of machine tool equipment and saves space required for machine tool installation. In addition, when machining both ends of the workpiece (W), the tool spindle (2) is oriented perpendicular to the first axis (see FIG. 1), which avoids interference with the tailstock (5) and shortens the center distance of the machine tool (1), thereby saving space required for machine tool installation. Furthermore, by providing a workpiece gripping device (16) to the turret (8) or the like that has been conventionally provided on the machine tool (1) and using the swivel function of the turret (8) to flip the workpiece (W), all machining of the workpiece (W) can be achieved at low cost.

[0043] In the above, a shaft workpiece is illustrated as the workpiece (W) and the explanation is based on this premise, however, this technology can be applied to not only shaft workpieces but also flange workpieces and irregular workpieces whose cross-sectional shape is different from a circle by using a workpiece holding device or workpiece hand according to the workpiece shape.

[0044] In addition, the structure opposing the work spindle (3) has been described as the tailstock (5), but as shown in FIG. 7, the tailstock (5) may be replaced with a well-known second work spindle (opposing spindle) (4), and a chuck (9), center, etc. may be attached to the second work spindle (4) to support the work (W) between the opposing work spindles (3) and (4).

[0045] Furthermore, the installation location of the workpiece gripping device (16) is not limited to the tool rest (7), and it may be provided on other existing devices of the machine tool (1), such as the headstock, tailstock, or steady rest. In addition to being provided on existing devices of the machine tool (1), the workpiece gripping device (16) may be provided in the machining space of the machine tool (1) in a fixed or movable state by a feed axis or the like as a dedicated device for gripping the workpiece (W). In addition, in FIG. 7, the workpiece gripping device (16) may be attached to the second workpiece spindle (4), and the indexing function of the second workpiece spindle (4) may be used to flip the workpiece (W) and perform center hole machining on the end surface of the workpiece. Note that if center hole machining on both end surfaces of the workpiece is not required, the workpiece gripping device (16) does not need to be provided with a workpiece flipping function. [Explanation of symbols]

[0046] (1):Machine tools (2):Tool spindle (3): First work spindle (4): Second work spindle (5): Tailstock (7): Lower tool rest (8): Turret (11): Centering tool (12):Deep hole machining tool (13): Work Hand (14): Turning tools (15): End mill tool (16): Workpiece gripping device (17): Temporary stand (18): Turning tools (W): Work

Claims

1. A method for machining a workpiece using a machine tool including a tool spindle capable of changing tools and having a swivel function, a first workpiece spindle that rotatably supports a workpiece, and a workpiece gripping device that grips the workpiece in a machining space, comprising: In step A, the workpiece is gripped by the workpiece gripping device so that its axis faces a second axis direction that is perpendicular or inclined to a first axis direction that is an axial direction of the first workpiece spindle, and a machining tool is attached to the tool spindle and the workpiece gripping device are moved relatively to each other to perform center hole machining of the workpiece and / or workpiece end machining of the periphery thereof including an end face; Next, in step B, a work hand that grips and releases the workpiece is attached to the tool spindle, and the workpiece is transferred from the workpiece gripping device to the workpiece hand by moving the tool spindle and the workpiece gripping device relatively with the axis of the workpiece facing the second axis direction. Next, in step C, the tool spindle is rotated so that the axis of the workpiece faces the first axis direction, and the workpiece is transported to a position where it can be transferred from the tool spindle to the first workpiece spindle; Subsequently, in step D, the workpiece is gripped by the first workpiece spindle and any one of cutting, thermal processing, grinding and polishing is performed.

2. The machine tool further includes a tailstock or a second work spindle facing the first work spindle, and the work gripping device is attached to a rotatable turret; In the step A, after performing the workpiece end processing on one end of the workpiece, the turret is rotated to invert the workpiece held by the workpiece holding device by 180°, and the workpiece end processing is also performed on the other end of the workpiece; 2. The method for machining a workpiece according to claim 1, wherein after step B, both ends of the workpiece are supported by the first workpiece spindle and the tailstock or the second workpiece spindle.

3. The method for machining a workpiece according to claim 2, characterized in that a temporary table for temporarily placing the workpiece is provided inside the machine tool, and in step B, a step is performed of placing the workpiece held by the workpiece hand attached to the tool spindle on the temporary table.

4. 4. The method for machining a workpiece according to claim 3, wherein the temporary stage is provided on a movable body within a machining chamber of the machine tool.

5. A machine tool for carrying out the workpiece machining method according to any one of claims 1 to 4.

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