Workpiece support device for machine tool, workpiece fixing device for machine tool, and sucker adsorption-type workpiece fixing device for machine tool

Abstract

To stably hold a workpiece in an accurate positioning state and to perform chamfering on the workpiece.SOLUTION: This workpiece support device comprises a plurality of lifting members 7 that supports a workpiece 3 on an annular support surface 10 of the upper end, and a required lifting member is raised in accordance with a shape and a size of the workpiece. The workpiece 3 is supported on the annular support surface 10 of the upper end of the lifting member 7. A vertically movable sucker 15 is stored in a sucker storage recess 6 of the lifting member 7. The sucker 15 is adsorbed on the workpiece 3 at an adsorption recess 17 and has an air hole communicated with the adsorption recess 17 in a center base 19. The adsorption recess 17 is positioned below a workpiece lower surface 9 in a state where the workpiece covers an upper end opening 21 of an adsorption storage part 6. The workpiece 3 is adsorbed on the annular support surface 10 through suction at an air hole 20, and the sucker is adsorbed on the workpiece lower surface in the adsorption state. In the adsorption state, the center base 19 is pulled downward through the sucker 15, and the workpiece is fixed on a table upper surface in the adsorption state.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a workpiece supporting device for a machine tool, a workpiece fastening device for a machine tool, and a suction cup type workpiece fastening device for a machine tool. [Background technology]

[0002] Patent Document 1 provides an example of a machine tool that is configured to fix a workpiece on a table to a table using an air suction method when the workpiece is subjected to machining such as chamfering using a milling cutter.

[0003] The machine tool includes a table on which a workpiece is placed, a clamping device disposed in front of the table, and a milling cutter disposed in front of the table for performing machining such as chamfering on the workpiece, the clamping device having upper and lower clamping pieces for clamping from above and below a protruding portion of the workpiece placed on the table that protrudes as required from the front edge of the table. Prior to performing the machining, the machine tool positions the workpiece placed on the table in the left-right and front-back directions as required, fixes the positioned workpiece to the table, and then moves the table as required and clamps the protruding portion that protrudes as required from the front edge of the table with the upper and lower clamping pieces. Then, in a workpiece clamping state in which the protruding portion is clamped by the upper and lower clamping pieces, the milling cutter performs machining on the processed portion of the workpiece that is in front of the clamped portion.

[0004] After the workpiece placed on the table is positioned left and right and front and rear as required, the positioned workpiece is fixed to the table, and the table starts moving forward with the lower clamping piece in the lowered state. After that, with the overhanging portion clamped as described above, one of the processing surfaces of the workpiece is machined.

[0005] After the machining of one of the workpiece surfaces is completed, the upper and lower clamping pieces release the protruding portion from the clamping position. In this released state, the table is rotated 90 degrees to machine a new workpiece surface.

[0006] The fixing means for the workpiece on the table described in Patent Document 1 has shallow recesses on the front and rear of the top surface of the table, and a number of air holes are provided in the bottom surface of the recesses in the vertical direction. The upper ends of the air holes open on the top surface of the bottom surface, and the lower ends are connected to an air suction device that sucks in air.

[0007] After the required positioning of the workpiece placed on the table has been completed, the air is sucked out from the space formed between the recess and the underside of the workpiece in order to fix the workpiece to the table.

[0008] However, in the past, if the roughness and flatness of the bottom surface of the workpiece were not good enough, there was a problem that outside air was drawn in and the workpiece was not completely fixed. In particular, in the case of a thin-walled and warped workpiece, the above-mentioned space was in communication with the outside at the warped part, so that the workpiece did not adhere well to the top surface of the table and the workpiece could not be fixed to the table.

[0009] If the fixation is incomplete in this way, after the required positioning of the workpiece placed on the table is completed, the set position of the workpiece on the table will shift due to the acceleration or deceleration of the table when the table starts to advance or when the table stops, or due to the acceleration or deceleration of the table when the table starts to rotate 90 degrees or when the rotation of the table stops, which will cause a problem that the workpiece cannot be machined accurately.

[0010] Furthermore, the machine tool in Patent Document 1 performs machining such as chamfering on a workpiece placed on a table in a clamped state in which the protruding portion extending from the front edge of the table is clamped between upper and lower clamping pieces. In order to clamp the workpiece in this manner, the workpiece must be stably fixed to the table, and the amount of protrusion from the front edge of the table must be such that it can be clamped from above and below by the upper and lower clamping pieces.

[0011] For this reason, there is a limit to the size of the workpiece that can be machined by the machine tool of Patent Document 1, and in Patent Document 1, for example, in the case of a rectangular parallelepiped workpiece that is square in plan view, the minimum length of one side of the workpiece is set to 150 mm. Therefore, chamfering of workpieces with a smaller side length, for example, small-sized workpieces with a side length of 50 to 130 mm, must be performed manually, resulting in poor productivity.

[0012] In addition, the conventional general work clamping means used when performing required machining on a workpiece was to place the workpiece on the upper surface of a work support stand installed on a table and press the upper surface of the workpiece with a pressing tool. However, since the sizes of the workpieces vary, it was necessary to have many different types of work support stands available to suit the sizes of the workpieces. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Patent Publication No. 2012-106327 Summary of the Invention [Problem to be solved by the invention]

[0014] One aspect of the present invention has been developed in consideration of the above-mentioned problems in the conventional art, and it is an object of the present invention to provide a suction cup type workpiece fixing device for a machine tool which can securely hold a workpiece in an accurately positioned state, thereby enabling the workpiece to be subjected to precise machining such as chamfering, and which can securely clamp the workpiece even if the workpiece is small, thereby enabling the required machining such as chamfering to be performed.

[0015] Another object of the present invention is to provide a work fixing device for a machine tool which, when performing required machining on a workpiece, eliminates the need to prepare a large number of different work support tables according to the shape and size of the workpiece, as was necessary in the past. [Means for solving the problem]

[0016] In order to solve the above problems, the present invention employs the following means. In other words, the work support device of the machine tool of the present invention is characterized in that it comprises a plurality of lifting members capable of supporting the underside of a workpiece with their horizontal upper end surface portions, all of which can rise above the base surface by the required length, the required lifting members rise in accordance with the shape and size of the workpiece, and the underside of the workpiece is supported by the upper end surface portions of the lifting members in the raised state.

[0017] A first aspect of the suction cup type workpiece fastening device for a machine tool according to the present invention comprises a plurality of lifting members each having a suction cup accommodating recess that is open at an upper end surface and is provided at the upper end side, the periphery of the open upper end surface is configured as an annular support surface that presents a horizontal plane and can support the underside of a workpiece, the required lifting members are configured to rise according to the shape and size of the workpiece, all of the lifting members can rise a required length above the base surface, and the annular support surfaces of all the raised lifting members are at the same height. Also, a suction cup that moves up and down is accommodated in the suction cup accommodating recess for suction-fixing the workpiece to the annular support surface, the suction cup is made of rubber and is adapted to be sucked to the workpiece by the suction recess of a skirt-shaped suction part for vacuum suction, the suction part has a central base portion provided with an air hole that communicates with the suction recess, and the suction cup is accommodated in the suction cup accommodating part with the suction recess open upward. With the workpiece placed on the annular support surface so as to cover the upper end opening of the suction cup accommodating recess, the suction recess of the suction cup is positioned below the lower surface of the workpiece, and with the workpiece placed in this state, suction through the air hole acts to obtain a preliminary suction state in which the lower surface of the workpiece is suctioned by the upper end opening of the suction cup accommodating recess.The suction cup is then raised in this preliminary suction state, and the peripheral portion of the suction recess presses the lower surface of the workpiece upwardly to be suctioned to the lower surface of the workpiece while preventing the workpiece from floating up from the annular support surface due to the workpiece suction action in the preliminary suction state.Furthermore, with the central base of the suction cup being elastically pulled downward while maintaining this suction state, a downward tensile state of the workpiece is obtained via the suction cup, whereby the workpiece is fixed to the annular support surface of the lifting member in a main suction state.

[0018] A second aspect of the suction cup type workpiece fastening device for a machine tool according to the present invention is the first aspect, wherein the lifting member is provided with a guide vertical hole in its axial direction, the upper end portion of the guide vertical hole is enlarged in diameter to form the suction cup accommodating recess, and an air pipe is inserted into the guide vertical hole. The air pipe can move up and down while being guided by the guide vertical hole, and an air passage is provided in the air pipe in its axial direction, the upper end of the air passage is connected to the air hole of the suction cup, and the air passage is connected to an air supply source which supplies negative pressure air or positive pressure air to the air hole. Also, the air pipe is moved up and down by a vertical movement device so that the suction cup can be moved up and down.

[0019] A third aspect of the suction cup type workpiece fastening device for a machine tool according to the present invention is the second aspect, wherein the lifting member is provided with a guide vertical hole in its axial direction, and an upper end portion of the guide vertical hole has an enlarged diameter to form the suction cup accommodating recess. An air pipe is inserted into the guide vertical hole and can move up and down while being guided by the guide vertical hole, and an air passage is provided in the air pipe in its axial direction, and an upper end of the air passage is connected to the air hole of the suction cup, and the air passage is connected to an air supply source that supplies negative pressure air or positive pressure air to the air hole. In order to move the suction cup up and down, a piston is provided at the lower end of the air pipe, and the piston can move up and down within a cylinder provided at the bottom of the lifting member, and the up and down movement of the piston is performed by controlling the supply of positive pressure air or negative pressure air to upper and lower ports which are provided at upper and lower parts sandwiching the cylinder and can communicate with the cylinder, and the upper port is also connected to the air passage, and is characterized by having the following configuration. (1) When the upper end of the suction cup accommodating recess is covered with the workpiece and the piston is in contact with or moved toward the bottom of the cylinder, negative pressure air is supplied to the upper port, thereby obtaining the preliminary suction state in which the underside of the workpiece is adsorbed to the upper opening of the suction cup accommodating recess. (2) While the pre-suction state is being maintained with negative pressure air being supplied to the upper port, positive pressure air is supplied to the lower port to raise the air pipe, causing the suction cup to rise and the peripheral portion of the suction recess to be adhered to the underside of the workpiece. (3) When negative pressure air is supplied to the lower port while the workpiece is in this suction state, the piston descends, and while the suction state is maintained, the central base of the suction cup is elastically pulled downward, and the workpiece is pulled downward via the suction cup, thereby fixing the workpiece to the table top in this suction state. (4) By supplying negative pressure air to the lower port and positive pressure air to the upper port, the fixation in the suction state by the suction cup is released.

[0020] A fourth aspect of the suction cup type workpiece fastening device for machine tool according to the present invention is characterized in that, in any of the first to third aspects, the workpiece is placed on the annular support surface so as to cover the upper end opening of the suction cup accommodating recess, and the suction recess of the suction cup is positioned below the lower surface of the workpiece, and positive pressure air is supplied from the air hole into the suction recess to eject air at the upper end opening of the suction cup accommodating recess, thereby allowing the workpiece to be floated and moved above the annular support surface.

[0021] Furthermore, the workpiece fixing device of the machine tool according to the present invention is characterized in that it comprises a plurality of lifting members capable of supporting the underside of a workpiece at their upper ends, all of which can rise above the base surface by the required length, the required lifting members rise in accordance with the shape and size of the workpiece, the underside of the workpiece is supported by the upper end surfaces of the lifting members in the raised state, and the workpiece is fixed to the upper ends of the lifting members by pressing the upper surface of the workpiece with a pressing tool. Effect of the Invention

[0022] When the suction cup type workpiece fastening device in the machine tool according to the present invention is used, the workpiece can be reliably held in an accurately positioned state, and the workpiece can be subjected to machining such as chamfering with high precision. Even if the workpiece is small in size, the workpiece can be reliably clamped and subjected to the required machining such as chamfering. Furthermore, with the present invention, it is not necessary to prepare many different types of workpiece support tables according to the shape and size of the workpiece, as in the conventional case, and space and labor can be saved. [Brief description of the drawings]

[0023] [Figure 1] 1 is a plan view illustrating a suction cup type workpiece fastening device of a machine tool according to the present invention; [Diagram 2] 1 is a plan view showing the arrangement and configuration of the lifting members and support members erected at the installation portion of the cross-shaped support frame. FIG. [Diagram 3] FIG. 4 is a perspective view illustrating the configuration of a lifting member and a support member. [Figure 4] 4 is a perspective view illustrating the configuration of the lifting member and the support member, and the state in which the lifting member and the support member support a workpiece. FIG. [Diagram 5] FIG. 2 is a cross-sectional view for explaining the configuration of a suction cup type workpiece fastening device of a machine tool. [Figure 6] FIG. 11 is a cross-sectional view illustrating a preliminary suction state of the suction cup. [Figure 7] 11 is an explanatory diagram illustrating a state in which the suction cup rises and the peripheral portion of the suction cup is attached to the underside of the workpiece when the suction cup is in a preliminary suction state; FIG. [Figure 8] FIG. 13 is an explanatory diagram illustrating a main suction state of the suction cup. [Figure 9] FIG. 13 is an explanatory diagram illustrating a state in which the fixation in the adsorbed state of the suction cup is released. [Figure 10] 1 is a side view showing a state in which the upper and lower clamping pieces are clamping a protruding portion of a large-sized workpiece while the milling cutter is chamfering the workpiece. FIG. [Figure 11] 1 is a plan view showing an outline of a process for positioning a workpiece by a positioning device. FIG. [Figure 12]1 is a side view showing a state in which the upper and lower clamping pieces are clamping a protruding portion of a small-sized workpiece while the milling cutter is chamfering the workpiece. FIG. [Figure 13] FIG. 11 is a plan view showing a process of performing measurement for work positioning using a movable measuring device. [Figure 14] FIG. 11 is an explanatory view showing another embodiment of the work clamp. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLES

[0024] In Figs. 1 to 5, a suction cup type workpiece fastening device (hereinafter also referred to as a workpiece fastening device) 1 of a machine tool according to the present invention is applied to a machine tool 2, for example, a chamfering machine 2a that performs chamfering on a workpiece 3 with a milling cutter 4. The workpiece fastening device 1 includes a plurality of lifting members 7 that are open at an upper end surface 5 and have a suction cup accommodating recess 6 at the upper end side that can accommodate a suction cup 15, which will be described later, and the outer circumferential surface of the lifting cylinder 7 is formed as a circumferential surface in this embodiment. The peripheral portion of the open upper end surface 5 is configured as an annular support surface 10 that presents a horizontal surface and can support the lower surface 9 of the workpiece 3. The required lifting members 7 are configured to rise according to the shape and size of the workpiece, and all the lifting members 7 can rise above a base surface 11 by a required length, and the annular support surfaces (in this embodiment, annular support surfaces) 10 of all the lifting members 7 that have risen are at the same height.

[0025] In this embodiment, as shown in Figures 2 and 4, the lifting member 7 is erected on installation sections 13a, 13a, 13a, 13a (Figure 4(B)), which are the tip part of the cross of a cross-shaped support frame 12 that can move in the front-rear and left-right directions and are arranged on a concentric circle.

[0026] As shown in Fig. 4(A), the annular support surface 10 (Fig. 3(A)) of all the lifting members 7 can be raised the same distance, for example 90 mm, above the base surface 11 (Figs. 2 and 4), and the annular support surfaces 10 of all the lifting members 7 that have been raised are at the same height. Furthermore, the diameter of the upper ends of the suction cup accommodating recesses 6 (Fig. 3(A)) of these four lifting members 7 is the same, for example set to 35 mm. Therefore, the inner diameter of the annular support surface 10 is set to 35 mm. The annular support surfaces 10 of all the lifting members 7 that are in the raised state are at the same height, and all the lifting members 7 can be in the lowered state in which the annular support surfaces 10 at their upper ends do not protrude from the base surface 11 (Fig. 4(B)).

[0027] In this embodiment, a support member 8 that does not perform lifting and lowering operations is provided in an upright state at the center of the cross of the cross-shaped support frame 12. As shown in Fig. 3(B), the support member 8 has a suction cup accommodating recess 6 at its upper end side, which is open at the upper end surface 5a and capable of accommodating a suction cup 15 (described later), similar to that of the lifting and lowering member 7, and the periphery of the upper end surface 5a is configured as an annular support surface (annular support surface in this embodiment) 10a that presents a horizontal surface and can support the underside 9 of the workpiece 3. The annular support surface 10a of the support member 8 is at the same height as the annular support surface 10 at the upper end of the lifting and lowering member 7 in the raised state (Fig. 4(A)).

[0028] The lifting and lowering movement of these four lifting members 7 is controlled so as to stably support the workpiece 3 in accordance with its shape and size, and so as to reliably perform the chamfering of the workpiece 3, as described below, with the edge portion of the workpiece clamped as required.

[0029] When using a workpiece fixing device 1 having such a configuration, the workpiece 3 can be appropriately supported in accordance with its shape and size by only the lifting member 7 raised as required, or by both the lifting member 7 raised as required and the support member 8, or even by only the support member 8.

[0030] For example, when the workpiece 3 to be supported is a rectangular parallelepiped workpiece having a square shape in a plan view, the workpiece 3 can have a side length of 50 to 310 mm. When supporting a relatively large workpiece 3 having a side length of 310 mm, as shown in Fig. 4(A), all of the four lifting members 7, 7, 7, 7 are in the raised state, and the workpiece 3 can be supported by the annular support surface 10 of the lifting member 7 in the raised state and the annular support surface 10a of the support member 8.

[0031] Conversely, when supporting a relatively small workpiece 3 having a side length of 50 to 180 mm, for example, as shown in FIG. 4(B), all of the lifting members 7 can be lowered and the workpiece 3 can be supported only by the annular support surface 10a of the support member 8.

[0032] Figure 4(C) shows a state in which a rectangular workpiece 3 is supported by the annular support surfaces 10, 10 of two lifting members 7a, 7b that are arranged in a straight line and are in the raised state and the annular support surface 10a of the support member 8, while the remaining two lifting members 7c, 7d are in the lowered state.

[0033] As described above, each of the lifting members 7 and the support members 8 is formed with the suction cup accommodating recesses 6 that are open at the upper ends, and the suction cup accommodating recesses 6 accommodate suction cups 15 that move up and down for suctioning and fixing the workpiece 3 to the annular support surfaces 10, 10a. The suction cups 15 provided on the lifting members 7 and the suction cups 15 provided on the support members 8 have the same configuration.

[0034] 3 and 5, the suction cup 15 is adapted to be attached to the underside 9 of the workpiece 3 by a suction recess 17 of a skirt-shaped suction portion 16 which expands in diameter towards the upper end for vacuum suction, and an air hole 20 communicating with the suction recess 17 is provided in a central base 19 of the suction portion 16. The suction cup 15 is accommodated in the suction cup accommodating portion 6 with the suction recess 17 open upward, and with the workpiece 3 placed on the annular support surface 10 (annular support surface 10a in the case of the support member 8) so as to cover an upper end opening 21 of the suction cup accommodating recess 6, the suction recess 17 is positioned below the underside 9 of the workpiece 3.

[0035] As a result of the suction through the air holes 20 acting with the suction recesses 17 positioned below the lower surface 9 of the workpiece 3, a preliminary suction state 22 is obtained in which the lower surface 9 of the workpiece 3 is suctioned to the upper end opening 21 of the suction cup accommodating section 6, as shown in Fig. 6, and the suction cups 15 rise in the preliminary suction state 22. Then, as shown in Fig. 7, the peripheral portion 23 of the suction recesses 17 presses the lower surface 9 of the workpiece 3 upward, while preventing the workpiece 3 from floating up from the annular support surface 10 due to the workpiece suction action in the preliminary suction state 22, and thereby the suction cups 15 are suctioned to the lower surface 9 of the workpiece 3.

[0036] 8, the central base 19 of the suction cup 15 is elastically pulled downward while maintaining the suction state, thereby obtaining a downward pulling state of the workpiece 3 via the suction cup 15. As a result, the workpiece 3 is fixed to the annular support surface 10 of the lifting member 7 in the main suction state 35.

[0037] As shown in Fig. 5, the lifting member 7 is provided with a guide hole 25 in its axial direction, the upper end portion of which is enlarged in diameter to form the suction cup accommodating recess 6, and an air pipe 26 is inserted into the guide hole 25. The air pipe 26 can move up and down while being guided by the guide hole 25, and an air passage 27 is provided in the air pipe 26 in its axial direction. The upper end of the air passage 27 is connected to the air hole 20 of the suction cup 15 via a connecting pipe member 28, and the air passage 27 is connected to an air supply source which supplies negative pressure air or positive pressure air to the air hole 20. The air pipe 26 is configured to be moved up and down by a vertical movement device 28 so that the suction cup 15 can be moved up and down.

[0038] In this embodiment, the vertical movement device 28 for moving the air pipe 26 up and down is provided with a piston 29 at the lower part of the air pipe 26 .

[0039] The piston 29 can move up and down within a cylinder 30 provided inside the table 3. The up and down movement of the piston 29 is achieved by controlling the supply of the positive pressure air or the negative pressure air to upper and lower ports 31, 32 which are provided at upper and lower positions sandwiching the cylinder 30 and which can communicate with the cylinder 30, and the upper port 31 is also connected to the air passage 27.

[0040] Next, the operation of the workpiece fastening device 1 having such a configuration will be described with reference to Figures 5 to 9. The arrows shown in Figures 6 to 9 indicate the direction of air movement. Figure 5 shows the initial state, in which the workpiece 3, which has been placed on the annular support surface 10 after being positioned as required in the left-right and front-rear directions on the annular support surface 10, is immediately before being sucked and fixed to the annular support surface 10, with the upper end opening 21 of the suction cup accommodating recess 6 being covered by the workpiece 3.

[0041] FIG. 6 shows the preliminary suction state 22, in which the upper opening 21 of the suction cup accommodating recess 6 is covered with the workpiece 3 and the piston 29 is in contact with the bottom 34 of the cylinder 30. In this state, negative pressure air is supplied to the upper port 31, so that the underside 9 of the workpiece 3 is suctioned to the upper opening 21 of the suction cup accommodating recess 6.

[0042] Fig. 7 shows a state in which, while maintaining the preliminary suction state 22 (Fig. 6) in which negative pressure air is being supplied to the upper port 31, positive pressure air is supplied to the lower port 32 to raise the air pipe 26. With this raising, as shown in Fig. 7, the peripheral portion 23 of the suction recess 17 presses the lower surface 9 of the workpiece 3 upward, and the peripheral portion 23 is suctioned to the lower surface 9.

[0043] FIG. 8 shows the state in which, while in this adsorbed state, negative pressure air is supplied to the lower port 32 to lower the piston 29, and while in this adsorbed state, the central base 19 of the suction cup 15 is elastically pulled downwards, resulting in a downward pulling state of the workpiece 3 via the suction cup 15, and the workpiece 3 is fixed to the annular support surface 10 in this adsorbed state 35.

[0044] 9 shows a state in which the fixation in the suction state by the suction cups 15 is released by supplying negative pressure air to the lower port 32 and positive pressure air to the upper port 31. By releasing the fixation, the workpiece 3 can be removed from the lifting member 7.

[0045] Next, an explanation will be given of the case where the work fastening device 1 of the machine tool according to the present invention is applied to a chamfering machine 2a, with regard to the process of positioning the work 3 on the annular support surface 10 of the lifting member 7, the process of suction cup adsorbing the work 3 to properly maintain the positioned state, the process of clamping the work 3 with the positioning maintained, and the subsequent process of chamfering the work 3.

[0046] 1 and 11 to 13, the chamfering machine 2a includes the lifting member 7 and support member 8 on which the workpiece 3 is placed, a positioning device 36 for positioning the workpiece 3 on the lifting member 7 and support member 8, a clamping device 37 disposed on the front side of the cross-shaped support frame 12 (FIG. 1), and a milling cutter 4 disposed on the front side of the cross-shaped support frame 12 for machining the workpiece 3. The clamping device 37 includes upper and lower clamping pieces 41, 42 (FIG. 12) for clamping only the upper end surface portion (the annular support surface 10a) of the support member 8, or a protruding portion 40 of the workpiece 3 placed on the upper end surface portion (the annular support surface 10a) of the support member 8 and the annular support surface 10 of the lifting member 7 from above and below. With the upper and lower clamping pieces 41, 42 in a work clamping state, clamping the protruding portion 40 as shown in Figures 10 and 12, the milling cutter 4 performs chamfering on the processed portion 43 (Figure 10) which forms the front side of the clamped portion of the workpiece 3.

[0047] In the chamfering machine 2a, the annular support surfaces 10, 10a are horizontal, and the cross-shaped support frame 12 (FIG. 1) can be rotated as required about an axis in the vertical direction by an indexing device.

[0048] The lower clamping piece 42 can take an elevated position protruding above the base surface 11 (FIGS. 1 and 4), a lowered position lower than the base surface 11, and a clamping position abutting against the lower surface 9 of the workpiece 3, and the overhanging portion 40 is formed by moving the workpiece 3 placed on the upper surface forward with the lower clamping piece 42 in the elevated position to bring the front surface of the workpiece 3 into abutment against the lower clamping piece 42. Then, with the lower clamping piece 42 in the lowered position, the cross-shaped support frame 12 moves forward a required amount, and then the lower clamping piece 42 rises to assume the clamping position, whereby the overhanging portion 40 is clamped by the upper and lower clamping pieces 41, 42, as shown in FIGS.

[0049] (1) Step of positioning the workpiece 3 on the annular support surfaces 10, 10a of the lifting member 7 and the support member 8 The workpiece 3 supported by the annular support surface 10 of the lifting member 7 has a required thickness and is square, rectangular, octagonal, or the like in a plan view. Examples of the shape and size of the workpiece 3 are as described above.

[0050] FIG. 10 shows a case where a large-sized workpiece 3 (for example, a large-sized workpiece 3 having a rectangular parallelepiped shape that is a square in plan view and has a side length of 300 mm) is supported.

[0051] In Fig. 10, the workpiece 3 is supported by the annular support surfaces 10, 10a of the lifting members 7, 7, 7, 7 and the support member 8. Prior to the clamping, the workpiece 3 is positioned as required by the annular support surfaces 10, 10a. The positioning is performed by using the positioning device 36 (equipped with the positioning tool 50 shown in Figs. 1 and 11 and a measuring device 51 (Fig. 13)).

[0052] Figure 11 shows the process of using the positioning tool 50 to perform general positioning in the left-right and front-back directions. The positioning is performed by pressing one corner portion 47 of the workpiece 5 against a right-angle positioning portion 52 formed by the positioning piece 50a of the advanced positioning tool 50 and the lower clamping piece 42 (Figure 10) extending in a direction perpendicular to the axial direction of the positioning tool 50.

[0053] Incidentally, when performing the operation of pressing the one corner portion 47 of the workpiece 3 against the right-angle positioning portion 52 in this manner, it is advisable to supply positively pressurized air from the air holes 20 (FIG. 5) of the suction cup 15 into the suction recess 17 and eject the air at the upper end opening 21 of the suction cup accommodating recess 6. This allows the workpiece 3 to be lifted up by the annular support surfaces 10, 10a and moved smoothly. This movement of the workpiece can be performed without hindrance, since the peripheral portion 23 of the suction recess 17 of the suction cup 5 does not protrude from the upper end surface portion 5 of the suction cup accommodating recess 6.

[0054] Fig. 13 shows a procedure for making appropriate corrections based on the measurement results of the measuring device 51 in order to improve the accuracy of the chamfering. In this embodiment, as shown in Fig. 13, the measuring device 51 has a movable probe 51a that can be advanced and retreated, attached to a moving frame 54 that can move in the left-right direction (the moving direction of the milling cutter) F. The measuring device 51 advances the probe 51a while positioned at the left and right ends of the workpiece 3, and the tip 51b of the probe is brought into contact with the front surface 3a of the workpiece 3. This measures the distance between the tip 51b of the probe 51a in the retreated state and the front surface 3a at the left and right ends. If the two distances are not the same, the cross-shaped support frame 12 is rotated by a required angle around its axis to adjust the two distances to be the same. This makes it possible to position the workpiece 3 on the annular support surfaces 10, 10a prior to the clamping so that the front surface 3a of the workpiece 3 is correctly parallel to the left-right direction F.

[0055] (2) Suction cup attachment process for the workpiece The workpiece 3 positioned in this manner is subjected to chamfering, and what is important is to reliably maintain the positioning of the workpiece 3. To this end, the workpiece 3 is fixed to the annular support surfaces 10, 10a in accordance with the steps described with reference to Figs.

[0056] (3) Workpiece clamping process After the workpiece 3 has been positioned in this manner, the lifting member 7 and the support member 8 are advanced a required distance by advancing the cross-shaped support frame 12, taking into consideration the size (depth) of the chamfer. Thereafter, as shown in Figures 10 and 12, the overhanging portion 40 is held by the upper and lower holding pieces 41, 42, thereby clamping the workpiece 2.

[0057] (4) About the workpiece chamfering process In this workpiece clamped state, the milling cutter 4 performs chamfering on the edge portion of the workpiece 43, as shown in, for example, FIGS. The chamfering process according to the present invention is carried out through the above steps, and when used according to the present invention, the two problems described above in Patent Document 1 can be solved, and machining, for example chamfering, can be performed on a wide range of workpieces. The two problems referred to here are the first and second problems described below. (1) First problem If the roughness and flatness of the bottom surface of the workpiece are not good enough, outside air will be drawn in, causing the workpiece to be incompletely fixed to the table. (2) The second problem In the case of a thin-walled warped workpiece, the space is open to the outside at the warped portion, which causes poor adhesion of the workpiece to the top surface of the table, making it impossible to fix the workpiece to the table.

[0058] The reason why the work fastening device 1 according to the present invention can solve the first problem is that the work fastening device is configured using suction cups made of rubber that have good adhesion, and therefore the effects of the surface roughness and flatness of the work are mitigated compared to conventional devices.

[0059] The reason why the workpiece fastening device 1 can solve the second problem is that the present invention has the following configuration: "the suction at the air holes 20 acts to obtain the preliminary suction state 22 (FIG. 6) in which the underside 9 of the workpiece 3 is suctioned at the upper end opening 21 of the suction cup accommodating recess 6, the suction cups 15 rise in the preliminary suction state 22 (e.g., rise by about 1 mm), the peripheral portion 23 of the suction recess 17 presses the underside 9 of the workpiece 5 upward while preventing the workpiece 3 from floating up from the table top surface due to the workpiece suction action in the preliminary suction state, and the suction cups 15 are suctioned to the underside 9 of the workpiece 5, and the central base portion 19 of the suction cups 15 is elastically pulled downward while maintaining the suction state, thereby obtaining a downward tension state of the workpiece 3 via the suction cups 15, and thereby the workpiece 3 is fixed in the main suction state to the annular support surface 10 of the lifting member."

[0060] As a result, even if the workpiece is thin and warped, the rising action of the suction cups 15 can reliably adsorb and fix the workpiece 3 to the annular support surface 10, allowing accurate machining (chamfering, etc.) to be performed on the workpiece 3.

[0061] 14 shows another embodiment of clamping the workpiece 3 when subjecting the workpiece to required machining, in which the lower surface 9 of the workpiece 3 is supported by the upper end surface 55 of one or more of the lifting members 7 and / or the upper end surface 56 of the support member 8 in the raised state, and the upper end surface 57 of the workpiece 3 is pressed by the pressing tool 53 to fix the workpiece 3 to the upper end surface 55 and the upper end surface 56. In this case, the lifting member 7 to be lifted is set as required according to the size of the workpiece so that the workpiece 3 can be stably supported. The workpiece 3 may also be supported only by the upper end surface 56 of the support member 8 with all of the lifting members 7 in the lowered state.

[0062] Incidentally, the conventional general work clamping means used when subjecting the work 3 to required machining was to place the work on the upper surface of a work support stand installed on a table and press the upper surface of the work with a pressing tool. In this case, since the sizes of the workpieces vary, it was necessary to have many different types of work support stands available according to the sizes of the workpieces.

[0063] In contrast to this, when the work clamping method using the lifting member 7 is used, it is not necessary to prepare many different types of work support tables, which not only saves space but also reduces the labor required for management.

[0064] The work fastening device according to the present invention may be configured only with a plurality of lifting members 7 capable of supporting the lower surface of the work with their horizontal upper end surfaces. Also, in the work fastening device according to the above embodiment, the support members 8 may be configured as the lifting members 7. [Explanation of symbols]

[0065] 1 Workpiece fixing device 2 Machine tools 3 Work 4 Milling 5 Upper end surface 6 Suction cup receiving recess 7 Lifting member 8 Support members 9 Bottom side 10 Annular support surface 10a Annular support surface 11 Base 12 Cross-shaped support frame 15 sucker 16 Adsorption part 17 Adsorption recess 20 Air Vents 21 Top opening 22 Pre-adsorption state 23 Periphery 25 Guide hole 26 Air Pipe 27 Airway 29 Piston 30 Cylinder 35 pieces of adsorption 37 Clamping device 40 Overhanging part 41 Upper clamping piece 42 Lower clamping piece 53 Pressing tool 56 Upper end surface section

Claims

1. A work support device for a machine tool, comprising a plurality of lifting members capable of supporting the underside of a workpiece with their horizontal upper end surface portions, all of which can rise a required length above a base surface, the required lifting members rising in accordance with the shape and size of the workpiece, and the underside of the workpiece being supported by the upper end surface portions of the lifting members in the raised state.

2. a plurality of lifting members each having a suction cup accommodating recess that is open at an upper end surface and is provided at the upper end side, the peripheral portion of the open upper end surface is configured as an annular support surface that presents a horizontal plane and can support the underside of a workpiece, and the required lifting members are configured to rise in accordance with the shape and size of the workpiece, all of the lifting members can rise a required length above the base surface, and the annular support surfaces of all the lifting members that have been raised are at the same height, Further, a suction cup that moves up and down is accommodated in the suction cup accommodating recess for suction-fixing the workpiece to the annular support surface, The suction cup is made of rubber and is adapted to be attached to the workpiece by a suction recess in a skirt-shaped suction portion for vacuum suction, an air hole communicating with the suction recess is provided in the central base of the suction portion, and the suction cup is accommodated in the suction cup accommodating portion with the suction recess open upward, a state in which the workpiece is placed on the annular support surface so as to cover an upper end opening of the suction cup accommodating recess, and the suction recess of the suction cup is located below a lower surface of the workpiece, When the workpiece is placed on the suction cup, the suction through the air hole acts to obtain a preliminary suction state in which the lower surface of the workpiece is suctioned by the upper end opening of the suction cup accommodating recess, the suction cups are raised in the preliminary suction state, and the suction action of the workpiece in the preliminary suction state prevents the workpiece from floating up from the annular support surface, while a peripheral portion of the suction recess presses the lower surface of the workpiece upward, so that the suction cups are attracted to the lower surface of the workpiece, a suction cup type workpiece fastening device for a machine tool, characterized in that the central base of the suction cup is elastically pulled downward while maintaining the suction state, thereby obtaining a downward pulling state of the workpiece via the suction cup, whereby the workpiece is fixed in this suction state on the annular support surface of the lifting member.

3. The lifting member has a guide hole formed in its axial direction, and an upper end portion of the guide hole has an enlarged diameter to form the suction cup accommodating recess, an air pipe is inserted into the guide vertical hole, the air pipe being guided by the guide vertical hole so as to be able to move up and down, an air passage is provided in the air pipe in its axial direction, an upper end of the air passage is connected to the air hole of the suction cup, and the air passage is connected to an air supply source which supplies negative pressure air or positive pressure air to the air hole, 3. A suction cup type workpiece fastening device for a machine tool according to claim 2, further comprising a vertical movement device for moving said air pipe up and down so as to move said suction cup up and down.

4. The lifting member is provided with a guide hole in its axial direction, and an upper end portion of the guide hole is enlarged in diameter to form the suction cup accommodating recess, an air pipe is inserted into the guide vertical hole, the air pipe being guided by the guide vertical hole so as to be able to move up and down, an air passage is provided in the air pipe in its axial direction, an upper end of the air passage is connected to the air hole of the suction cup, and the air passage is connected to an air supply source which supplies negative pressure air or positive pressure air to the air hole, A suction cup type workpiece fastening device for a machine tool as claimed in claim 3, further comprising: a piston provided at the lower end of said air pipe so as to be able to move said suction cup up and down, said piston being able to move up and down within a cylinder provided at the lower part of said lifting member, said piston being able to move up and down by controlling the supply of said positive pressure air or said negative pressure air to upper and lower ports which are provided at upper and lower parts sandwiching said cylinder and which can communicate with said cylinder, and said upper port is also connected to said air passage, said device comprising the following: (1) When the upper end of the suction cup accommodating recess is covered with the workpiece and the piston is in contact with the bottom of the cylinder or moved toward the bottom, negative pressure air is supplied to the upper port, thereby obtaining the preliminary suction state in which the underside of the workpiece is adsorbed to the upper end opening of the suction cup accommodating recess. (2) While the pre-suction state is being maintained with negative pressure air being supplied to the upper port, if positive pressure air is supplied to the lower port to raise the air pipe, the suction cup will rise and the peripheral portion of the suction recess will be adhered to the underside of the workpiece. (3) When negative pressure air is supplied to the lower port while the workpiece is in this adsorbed state, the piston descends, and while the workpiece is still in this adsorbed state, the central base of the suction cup is elastically pulled downward, and the workpiece is pulled downward via the suction cup, thereby fixing the workpiece to the table top in this adsorbed state. (4) By supplying negative pressure air to the lower port and positive pressure air to the upper port, the fixation in the suction state by the suction cup is released.

5. 5. A suction cup type workpiece fastening device for a machine tool as set forth in any one of claims 2 to 4, characterized in that, with the workpiece placed on the annular support surface so as to cover the upper end opening of the suction cup accommodating recess, and with the suction recess of the suction cup positioned below the lower surface of the workpiece, positive pressure air is supplied from the air hole into the suction recess, causing air to be ejected at the upper end opening of the suction cup accommodating recess, thereby allowing the workpiece to be floated and moved above the annular support surface.

6. A work fastening device for a machine tool, comprising a plurality of lifting members capable of supporting the underside of a workpiece at their upper ends, all of which can rise a required length above a base surface, the required lifting members rising in accordance with the shape and size of the workpiece, the underside of the workpiece being supported by the upper end surfaces of the lifting members in the raised state, and the workpiece being fixed to the upper ends of the lifting members by pressing the upper surface of the workpiece with a pressing tool.

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