JP4751477B1 - Work clamping device in machine tools - Google Patents

Abstract

Provided is a clamping device capable of accurately rotating a workpiece in accordance with an indexing angle of a table, and thereby processing a side surface of the workpiece at an accurately indexed angle. .
A work 5 on a table 3 provided with an indexing device 20 that rotates about an axis in the vertical direction is placed on a position above the table 3 and is moved up and down using a lifting and lowering pressing means 19 that can move up and down. Press toward the top. The lifting / lowering pressing means 19 is provided with a lifting / lowering member 47 that can move up and down on a rod 45a of a fluid pressure cylinder 42a that can expand and contract in the vertical direction, and a control motor 56 is provided on the lifting / lowering member 47. A connecting shaft 60 is connected to the motor shaft 55 of the control motor 56, and a pressing tool 66 is connected to the lower end of the connecting shaft 60. The motor shaft 55, the connecting shaft 60, the pressing tool 66, and the table 3 have the same vertical axis, and the control motor 56 and the table 3 can rotate in synchronization.
[Selection] Figure 1

Description

  The present invention relates to a workpiece clamping device in a machine tool. More specifically, a workpiece in a machine tool that can accurately rotate the workpiece in accordance with the indexing angle of the table and thereby perform processing on the side surface of the workpiece at the accurately indexed angle. The present invention relates to a clamping device.

  Japanese Laid-Open Patent Publication No. 2007-229828 has been proposed as a work clamping device for a double-sided side milling machine, which has been developed by applying accurate end face machining without causing rotational deviation of the work.

  As shown in FIGS. 7 to 8 (FIGS. 1 and 2 of Patent Document 1), the clamp device a includes an index table c provided around a processing frame b and rotating around a vertical axis, An upper clamp mechanism e, which is provided at the upper part of the frame b, clamps on the same axis as the axis of the index table c, and clamps the workpiece d on the index table c, and the upper clamp mechanism e And a control motor f that rotates around the axis. The upper clamp mechanism e transmits the pressing force to the upper clamp j in order to clamp the upper clamp j including the clamp cylinder g and the rod h and the workpiece d on the index table c by the upper clamp j. The control motor f is configured to start and stop in synchronization with the index table c and rotate the pusher k by the same angle.

  As shown in FIG. 8, a specific rotation structure of the upper clamp mechanism e is such that the upper outer cylinder m is screwed onto the outer periphery of the rod h of the clamp cylinder g, and the lower outer cylinder is connected to the lower end of the upper outer cylinder m. n is fixed with a bolt or the like, and the inner circumference of the lower outer cylinder n is formed in a tapered cylinder shape, and the inner diameter of the lower end is smaller than the inner diameter of the upper end. The pusher k is a round bar-like member, and an upper inner cylinder p is fitted to the upper end of the pusher k, and is fixed with bolts or the like together with a bearing holder q attached to the upper surface thereof. The upper inner cylinder p is a tapered cylindrical member having a large outer diameter at the upper end and a smaller inner diameter at the lower end. The upper inner cylinder p is housed in the lower outer cylinder n on the rod h side and rotates about its axis. It was held freely.

  A thrust bearing r is fitted into the bearing holder q, and this thrust bearing r is put in a bearing holder portion s formed on the inner periphery of the lower end of the upper outer cylinder m on the rod side.

  The rotating mechanism of the pressing tool k has a large-diameter gear t fitted on the outer periphery of the upper inner cylinder p, and a small-diameter gear u meshes with the large-diameter gear t. The main shaft v of the control motor f was fixed.

  The rotary action of the pressing tool k having the above-described configuration is such that when the pair of side surfaces of the workpiece d is finished, the pallet w on the index table c is moved to 90 degrees by the index table c so as to process the other pair of side surfaces. Rotate degrees. At this time, the control motor f is activated in synchronization with the rotation of the pallet w and thus the index table c, and the pusher k is rotated 90 degrees. The rotation of the pressing tool k can be performed with low friction by the thrust bearing q, and there is no deviation between the rotation of the pressing tool k and the rotation of the pallet w. For this reason, no rotational deviation occurs between the pressing tool k and the upper jig x or between the upper jig x and the upper surface of the workpiece d. Further, the right angle between the pair of side surfaces of the workpiece d and the other pair of side surfaces can be accurately obtained. Further, even if the workpiece d is a laminate of a plurality of workpieces, there is no rotational deviation between the workpieces, so that all the workpieces can be accurately processed on the side.

  However, in the case of the clamping device a having such a configuration, the axis y of the main shaft v of the control motor f and the axis z of the pressing tool k must be in a parallel state, so that the pressing tool k As described in the embodiment of Patent Document 1, the configuration in which the control motor f rotates the small-diameter gear u fixed to the main shaft v on the large-diameter gear t fitted on the outer periphery of the upper inner cylinder p. It is considered that a rotating mechanism in a state where a load in the lateral direction is applied to the pressing tool k, such as a configuration in which the two are engaged, must be adopted.

  And the rotation mechanism which rotates the said pressing tool k with the said control motor f is a taper cylindrical shape provided in the upper end part of the pressing tool k, as described in FIG. 8 (FIG. 2 of patent document 1). The upper outer cylinder p is brought into contact with the tapered inner peripheral surface b1 of the lower outer cylinder n formed in a tapered cylindrical shape, and the upper inner cylinder p is moved into the lower outer cylinder n. When the structure in which the upper inner cylinder p is rotatably held around the axis is adopted, the upper inner cylinder p is lifted when the pressing force of the clamp cylinder g acts on the pusher k strongly. As a result, there is a possibility that a gap is generated between the tapered outer peripheral surface a1 and the tapered inner peripheral surface b1.

  For this reason, when a lateral load is applied to the pressing tool k when the pressing tool k is rotated by the control motor f, the gap becomes a play of rotation, and the pressing tool k is distorted. In this way, when the runout occurs in the pressing tool k, when the upper clamp mechanism e is rotated in accordance with the rotation of the workpiece d by the index table c, the workpiece d is accurately rotated in accordance with the indexing angle. When the workpiece is a stack of a plurality of workpieces, misalignment of the rotation direction between the workpieces is likely to occur, and therefore, the side surface of the workpiece cannot be processed with an accurate index angle. There was a fear.

JP 2007-229828 A

  The present invention has been developed in view of the above-mentioned conventional problems, and can accurately rotate the work in accordance with the indexing angle of the table. An object of the present invention is to provide a workpiece clamping device in a machine tool that can perform machining at a proper angle.

In order to solve the above problems, the present invention employs the following means.
That is, a workpiece clamping device (hereinafter referred to as a workpiece clamping device) in a machine tool according to the present invention is configured such that a workpiece on a table having an indexing device that rotates about an axis in the vertical direction is disposed at an upper position of the table. A workpiece clamping device in a machine tool that is configured to be pressed toward the upper surface of the table by using a lifting and lowering pressing means that can move up and down, and configured to rotate the workpiece in the workpiece pressing state , the lifting and pressing means Is provided on the vertical movement part of the lifting device fixed to the clamp frame provided in the machine main body, and is provided with a lifting member which can be moved up and down by being guided by a vertical guide provided on the clamp frame and extending in the vertical direction. ing. The elevating member can be moved up and down by the up and down movement of the up and down moving part, and the elevating member is provided with a control motor on the pressing side having a motor shaft whose axis is in the up and down direction. Is connected to the elevating member by at least a thrust bearing, and a pressing tool whose axis is in the vertical direction is connected to the lower end of the connecting shaft. The axis of the motor shaft, the connecting shaft, the pressing tool, and the table are aligned. In addition, the motor shaft, the connecting shaft , and the pressing tool rotate together with the work around the corresponding axis line in the work pressing state by the lifting and lowering pressing means by the rotation of the control motor on the pressing side. In addition, the pressing-side control motor and the table-side control motor that rotates the table about the axis can be rotated synchronously. By this synchronous rotation, the pressing tool and the table are the same across the workpiece. It is characterized by being rotated synchronously by an angle.

  In the work clamp device, the lifting device may be a fluid pressure cylinder that can expand and contract in the vertical direction, and the vertical movement portion may be a rod of the fluid pressure cylinder.

  Further, in the work clamp device, the vertical movement portion is screwed with a drive screw shaft that is rotated forward and backward by a servo motor, and the drive screw shaft is rotated forward and reverse. It is preferable that the vertical movement unit is configured to be able to move up and down while being prevented from rotating by the rotation preventing unit.

  In the work clamp device according to the present invention, the axes of the motor shaft, the connecting shaft, the pressing tool, and the table are aligned, and the pressing tool and the table are rotated synchronously by the same angle. However, the elevating member is structured such that it can be moved up and down stably while being guided by a vertical guide provided in the clamp frame extending in the vertical direction.

  Therefore, according to the present invention, the work clamped on the table can be accurately rotated in accordance with the indexing angle by the indexing device. Further, even when the workpiece is a laminated workpiece in which a plurality of plate-like workpieces are laminated, the laminated workpiece can be correctly rotated without causing a shift between the plate-like workpieces. Thereby, the side surface of the workpiece can be machined at an accurate index angle.

It is a perspective view showing the case where the work clamp device concerning the present invention is applied to the double-head milling machine. It is a perspective view which shows the clamp state of the workpiece | work by a workpiece | work clamp apparatus. It is a side view which shows an indexing device in the state where a work was clamped. It is a side view explaining a raising / lowering press means. It is a side view which shows the clamped state of a laminated workpiece. It is a partial cross section side view explaining the other structure of a raising / lowering apparatus. It is a side view explaining the conventional workpiece clamp apparatus. It is sectional drawing explaining the rotation structure of the upper clamp mechanism of the workpiece clamp apparatus.

  1 and 2, a workpiece clamping device 1 according to the present invention is applied to clamp a workpiece 5 on a table 3 attached to a machine tool 2, for example, a double-head milling machine 2a, to a required state. The double-headed milling machine 2a is configured to simultaneously mill two opposing workpiece surfaces 4a, 4a, 4b, and 4b (FIG. 2) of a workpiece 5 that has a square or rectangular shape in plan view, and to face opposite corner portions 4c and 4c. 4d, 4d (FIG. 2), such as simultaneous chamfering, can be selectively performed by positioning the work 5 as required, and is moved and controlled in the left-right direction F1 by a built-in numerical controller. 1 and a second head 7, and the milling shafts 11 and 12 are attached to the main shafts 9 and 10 of the first and second heads 6 and 7. They are provided in a horizontal state so that their axes coincide with each other.

  The work clamp device 1 is provided on a clamp frame 17, and the clamp frame 17 is connected to a base 15 of a machine body 14 in a moving path 13 provided between the first and second heads 6 and 7. It is guided by front and rear rails (not shown) provided in the front and rear, and is controlled to move in the front-rear direction F2.

  As shown in FIG. 1, the work clamp device 1 includes a table 3 provided at the lower portion of the clamp frame 17 and an elevating and pressing means 19 provided at the upper portion of the clamp frame 17.

  The table 3 includes an indexing device 20 that divides the outer periphery of the work 5 on the table 3 into a required angle in the circumferential direction as shown in FIGS. The workpiece 5 is placed via the workpiece support base 22. As shown in FIG. 3, the indexing device 20 is rotatable by an outer ring member 25 fixed to the lower frame portion 23 of the clamp frame 17 and a cross roller bearing 26 interposed between the outer ring member 25 and the outer ring member 25. The inner ring member 27 is provided, and the table 3 is supported by the inner ring member 27. The table 3 is fixed to the upper portion 30 of the drive shaft 29 having the same axis as that by a bolt or the like, and can be rotated around the axis 37 of the drive shaft 29 together with the drive shaft 29 in a horizontal plane. Yes. A lower end 31 of the drive shaft 29 is connected via a speed reducer 35 to a motor shaft 33 that protrudes upwardly on a table-side control motor (a motor that can accurately control the rotation angle, such as a servo motor or a stepping motor). Thus, the axis 36 of the table 3, the axis 37 of the drive shaft 29, and the axis 39 of the motor shaft 33 are vertically aligned with each other. Further, the inner ring member 27 is provided with a brake device 41 for generating a frictional action against the fixed flange 40 fixed to the lower frame portion 23. By the brake action of the brake device 41, the milling cutters 11, The table 3 is prevented from rotating while 12 is processing the workpiece 5.

  As shown in FIGS. 1 and 4, the elevating and lowering means 19 includes an elevating device 42 as a fluid pressure cylinder (air cylinder, hydraulic cylinder, etc.) 42 a that can expand and contract in the vertical direction, and an upper frame portion 43 of the clamp frame 17. It is fixed to. And the raising / lowering member 47 is provided in the up-and-down moving part 45 as the rod 45a of this fluid pressure cylinder 42a. In the present embodiment, the upper end 48 of the elevating member 47 is connected to the lower end portion 46 of the rod 45a via a connecting member 49, and the elevating member 47 is a rod accompanying the expansion and contraction operation of the fluid pressure cylinder 42a. By the vertical movement of 45a (that is, the vertical movement of the vertical movement part 45), it can be moved up and down by being guided by vertical guides 50, 50 provided on the left and right of the upper frame part 43 and extending in the vertical direction. The upper portion 52 of the front side portion 51 of the elevating member 47 has an accurate rotation angle such as a pressing-side control motor (a servo motor, a stepping motor or the like) having a downwardly projecting motor shaft 55 whose axis 53 is the vertical direction. A motor 56 that can be controlled is provided, and a connecting shaft 60 whose axis 59 is in the vertical direction is connected to the motor shaft 55 via a speed reducer 57 in this embodiment, for example, using bolts. . The intermediate portion of the connecting shaft 60 is supported by a radial bearing 62 which is a needle bearing, for example, and the upper and lower portions thereof are supported by thrust bearings 63 and 63. A pressing tool 66 having an axis 65 in the vertical direction is connected to the lower end 64 of the connecting shaft 60.

  The axis 53 of the motor shaft 55, the axis 59 of the connecting shaft 60, the axis 65 of the pressing tool 66, and the axis 36 of the table 3 are vertically aligned with each other. The rotation of the pressing tool 66 around the axis 65 can be stably performed with low friction by the radial bearing 62 and the thrust bearings 63 and 63. By the rotation of the control motor 56 on the pressing side, the motor shaft 55, the connecting shaft 60, and the pressing tool 66 can rotate integrally around the corresponding axes 53, 59, 65.

  As shown in FIG. 2, the pressing tool 66 presses the upper surface 67 of the work 5 on the upper surface 21 of the table 3 downward. For example, as shown in FIG. 5, the workpiece 5 has a rectangular shape or a square shape in plan view (in FIG. 2, a rectangular shape), and a plurality of (for example, four) relatively thin plate-like workpieces 69 are stacked. Is a laminated workpiece 5a. After the laminated workpiece 5a is positioned and installed on the upper surface 70 of the workpiece support 22 placed on the upper surface 21, the upper surface 67 of the laminated workpiece 5a is placed on the upper surface 21 by the pressing tool 66. The laminated workpiece 5a is clamped by pressing toward it.

  Now, as shown in FIG. 2A, the opposed work surfaces 4a, 4a of the laminated workpiece 5a are directed in the left-right direction and the other opposed work surfaces 4b, 4b are directed in the front-rear direction, and the clamp When the frame 17 is moved back and forth as required, the laminated workpiece 5a can be moved back and forth together with the clamp frame 17 and can be arranged at a processing place. With the clamp frame 17 moved in this way, the first and second processed surfaces 4a and 4a of the laminated workpiece 5a are processed by the first processing amount 4a and 4a by the amount to be processed. The second heads 6 and 7 are moved toward the laminated workpiece 5a. Then, a motor (not shown) is driven to rotate the milling cutters 11 and 12 of the respective heads to start cutting the processed surfaces 4a and 4a. At this time, by moving the clamp frame 17 in the front-rear direction as necessary, the milling surfaces 11 and 12 can simultaneously cut the opposed work surfaces 4 a and 4 a of the workpiece 5.

  After the completion of cutting, the table 3 is rotated by 90 degrees as shown in FIG. 2B, and the other opposing workpiece surfaces 4b and 4b are cut in the same manner. The control motor 56 is activated to rotate the pressing tool 66 by 90 degrees. At this time, the control motor 56 on the pressing side and the control motor 32 on the table side that rotates the table 3 around the axis 36 can be rotated synchronously, and the pressing tool 66 and the table 3 can be rotated by this synchronous rotation. Synchronous rotation is performed by the same angle (90 degrees in this embodiment). The motor shaft 55, the connecting shaft 60, the pressing tool 66, and the axes 3, 59, 65, and 36 of the table 3 are aligned with each other, and the elevating member 47 is connected to the upper frame portion 43. Since the vertical guides 50, 50 provided in the vertical direction are stably guided by the vertical guides 50 and 50 and can be moved up and down, there is no possibility that the pressing tool 66 will run out. Therefore, the laminated workpiece 5a can be correctly rotated by 90 degrees without causing a rotational shift of the laminated plate-like workpieces 69. Therefore, accurate side surface processing can be performed on all the stacked plate-like workpieces.

  The present invention is by no means limited to those shown in the above-described embodiments, and it goes without saying that various design changes can be made within the scope of the claims. One example is as follows.

(1) The lifting device 42 may be configured as a lifting device 42b using a servo motor 70 as shown in FIG. 6 in addition to the fluid pressure cylinder 42a. The elevating device 42 b is fixed to the upper frame portion 43 of the clamp frame 17. The elevating member 47 is provided in the up and down moving part 45 as a nut member 45b screwed to the drive screw shaft 71 of the elevating device 42b rotated forward and backward by the servo motor 70. In this embodiment, the elevating member 47 is moved up and down by connecting the upper end 48 via a connecting member 49 to the lower end 73 of the cylindrical member 72 provided integrally with the nut member 45b. Provided in the portion 45. The elevating member 47 is provided on the left and right sides of the upper frame portion 43 by the vertical movement of the nut member 45b of the elevating device 42b (that is, the vertical movement of the vertical moving portion 45) and extends in the vertical direction. It can be moved up and down by being guided by the vertical guides 50 and 50.

(2) The connecting shaft 60 may be directly connected to the motor shaft 55 of the control motor 56 on the pressing side without using the speed reducer 57.

(3) The motor shaft 33 of the control motor 32 on the table side may be in the horizontal direction in addition to the vertical state as described above. In this case, the rotation of the motor shaft 33 can be transmitted to the drive shaft 29 via, for example, a bevel gear device (not shown), whereby the table 3 can be rotated about its axis.

DESCRIPTION OF SYMBOLS 1 Work clamp apparatus 2 Machine tool 2a Double-head milling machine 3 Table 5 Work 17 Clamp frame 19 Lifting press means 20 Indexing device 23 Lower frame part 29 Drive shaft 32 Table side control motor 33 Motor shaft 36 Table axis 37 Drive shaft Axis 39 Motor shaft axis 42 Elevating device 42a Fluid pressure cylinder 42b Elevating device using servo motor 43 Upper frame portion 45 Vertical moving portion 45a Rod 45b Nut member 47 Elevating member 50 Guide 53 Motor shaft axis 55 Motor shaft 56 On the pressing side Control motor 59 Connection shaft axis 60 Connection shaft 65 Press tool axis 66 Press tool 70 Servo motor

Claims (3)

The work on the table comprising an indexing device rotating in a vertical direction around the axis, is made as to press toward the upper surface of the table using the lifting pushing means capable of and moved up and down is arranged above the position of the table A workpiece clamping device in a machine tool configured to rotate a workpiece in the workpiece pressing state ,
The lifting / lowering pressing means is moved up and down by a vertically moving portion of a lifting device fixed to a clamp frame provided in the machine body and guided by a vertical guide provided on the clamp frame and extending in the vertical direction. A member is provided, the elevating member can be moved up and down by the up and down movement of the up and down moving unit, and the elevating member is provided with a control motor on the pressing side having a motor shaft whose axis is the up and down direction, The motor shaft is connected to a connecting shaft whose axis is in the vertical direction. The connecting shaft is supported by the elevating member by at least a thrust bearing, and the axis is vertically connected to the lower end of the connecting shaft. A certain pressing tool is connected, and the motor shaft, the connecting shaft, the pressing tool, and the axes of the table are coincident with each other, and by the rotation of the control motor on the pressing side, In the work the pressed state by the elevating pressing means, the motor shaft and the said connecting shaft and pressing applying member is, it is possible to rotate as the workpiece integrally with the axis about which matching, the control motor of the pressing side, the The machine can be rotated synchronously with a control motor on the table side that rotates the table about the axis, and by this synchronous rotation, the pressing tool and the table are synchronously rotated by the same angle with the workpiece interposed therebetween. Work clamping device in machine.   2. The workpiece clamping device in a machine tool according to claim 1, wherein the lifting device is a fluid pressure cylinder that can be expanded and contracted in the vertical direction, and the vertical movement portion is a rod of the fluid pressure cylinder.   In the lifting device, the vertical moving portion as a nut member is screwed to a driving screw shaft that is rotated forward and backward by a servo motor, and the vertical moving portion is prevented from rotating by rotating the driving screw shaft forward and backward. 2. The work clamping device in a machine tool according to claim 1, wherein the work clamping device is configured to be prevented from rotating by a portion so as to move up and down.

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