JP4411291B2 - Work chatter vibration suppressing method and work support device - Google Patents

Description

  The present invention relates to suppression of so-called chatter vibration of a workpiece during machining, and more specifically, relates to a method for suppressing chatter of a workpiece during machining and a work support device capable of suppressing chatter.

  When machining such as cutting and grinding is to be applied to various workpieces, so-called chattering may occur in the workpiece due to the force acting on the workpiece from the tool. When chattering occurs, the machining dimensional accuracy of the workpiece, the surface roughness of the machining surface, and the like deteriorate, and further, machining may be difficult.

  If the shape of the workpiece is simple, it is easy to fix or clamp the workpiece on the base of the machine tool. If necessary, the workpiece is fixed in the vicinity of the processed part of the workpiece, and chatter is unlikely to occur. It can also be fixed firmly.

  However, in the case of a workpiece having a complicated shape, it is not always possible to fix the vicinity of the part to be processed. In this case, if the machining speed is slowed down, chattering can be suppressed to some extent, but the machining efficiency is lowered. Therefore, in order to maintain high machining efficiency, it is necessary to take measures to suppress the occurrence of some chatter.

  FIG. 1 shows an example of a conventional method for suppressing chatter. In this example, a case is shown in which the upper surface of one side of a workpiece having a thin box shape whose upper side is open is ground.

  In FIG. 1, the workpiece W is made of metal and has a box shape with the upper side opened, and the upper surface S of one of the vertical walls L is shown as being ground with a tool T attached to a machine tool (not shown). Yes. The workpiece W is fixed to the table 1 of the machine tool at the bottom wall B using a main clamp 2 shown in a simplified manner. Reference numeral 3 denotes a work support, which is fixed on the table 1. The shaft 4 protrudes from the casing 5 and is fixed in a state where the tip thereof is in contact with a predetermined position of the vertical wall L of the workpiece W. The support 3 will be briefly described below with reference to FIG.

  The casing 5 of the support 3 is composed of a casing body 6 that is open at one end side and a lid 7 that closes the opening, and forms a void 8 therein. The rear wall 6a of the casing body 6 and the lid 7 are coaxially perforated, and the shaft 4 is axially movable through these holes. A collet 9 is disposed around the shaft 4 in the space 8. Both ends of the collet 9 are in contact with the rear wall 6a and the lid 7 of the casing body 6 and cannot move in the axial direction. The outer diameter gradually increases toward the right in the figure.

A cylindrical piston 10 is disposed outside the collet 9 so as to surround the collet 9, and its inner diameter increases toward the right in the drawing so as to be parallel to the outer periphery of the collet 9. The piston 10 includes a flange 14, and the outer periphery thereof is in contact with the inner periphery of the casing body 6. Reference numeral 12 denotes a spring that urges the piston 10 leftward in the drawing. The casing body 6 is provided with a hydraulic port 13, and pressure fluid is supplied from a supply source (not shown) via the port 13, and acts on the left side surface of the flange portion 14 of the piston 10 in the space 8. The piston 10 is moved to the right side in the figure. When the piston 10 moves to the right side, the piston 10 reduces the diameter of the collet 9 and tightens the shaft 4.

When the hydraulic pressure is not applied, the piston 10 moves in the reverse direction, that is, the left side by the action of the spring 12, loosens the collet 9, and releases the shaft 4. Since the collet 9 does not tighten the shaft 4, the shaft can freely move in the axial direction. In FIG. 1, the workpiece W is fixed by the main clamp 2, and the support 3 is also clamped and fixed by an appropriate clamp (not shown). Then, the shaft 4 is pushed leftward in FIG. 2 by a spring (not shown), and its tip abuts against the side surface of the vertical wall L of the workpiece W. Supplying hydraulic support 3 in this state, the piston 10 moves to the right in FIG. 2, which by the Riko let 9 is reduced in diameter, the clamping shaft 4, the shaft 4 is disabled and the axial movement, the Fixed in position.

  In this way, the tool T is rotated and processed while the tip of the shaft 4 of the support 3 is in contact with the vertical wall L of the workpiece W on the upper surface S, that is, in the vicinity of the portion to be processed. At this time, the part to be processed of the workpiece W tends to vibrate in the direction indicated by the double-ended arrow A in FIG. This vibration is intended to be suppressed by keeping the shaft 4 in contact.

By the way, in the conventional suppression method, the shaft 4 is fixed. Therefore, when the workpiece W tries to swing from the neutral position shown in FIG. 2 to the right direction of the double-headed arrow A under the action of the tool T, the movement is blocked by the shaft 4, and the tip of the shaft 4 is blocked by the workpiece. It remains in contact with the vicinity of the processed portion of W. Therefore, in this range, there is an effect of suppressing the vibration of the workpiece. However, when the workpiece W swings to the left of the double-ended arrow A, the shaft 4 is fixed at the position shown in the figure, so that the workpiece W moves away from the tip of the shaft 4 and vibrations cannot be suppressed. . Therefore, the above-described conventional method cannot sufficiently suppress so-called chatter vibration, and there is a problem in the work machining accuracy.

  By the way, the vibration generated in the workpiece during machining with a tool is complicated, and for example, a primary vibration having a relatively large amplitude of 5 to 10 microns and a high-order vibration having a very small amplitude are overlapped. The inventor of the present invention has a high-order vibration having a small amplitude among these vibrations has a great influence on the finishing accuracy when the workpiece is machined, and this high-order vibration contacts some support. It has been found that it is greatly suppressed by bringing it into contact with the workpiece in a state having pressure.

  The present invention has been made based on the above knowledge, and even if chatter vibrations occur in the workpiece, the support member moves following the movement of the workpiece portion that vibrates and always moves in the vicinity of the workpiece portion of the workpiece. To provide a work support device and a method for suppressing chatter vibrations of a workpiece, which can maintain contact in a state of having a contact pressure, thereby suppressing higher-order vibrations and obtaining good machining accuracy. Is the subject.

  In order to solve the above-described problems, a workpiece support device according to the present invention includes a fixed support unit and a follow-up support unit, and the fixed support unit has a predetermined direction with respect to the vicinity of a workpiece portion of the workpiece. A fixed abutting member that can be abutted and fixed at a predetermined position is provided. On the other hand, the follow-up support unit abuts against the vicinity of the work portion of the workpiece from the same direction as the fixed abutting member. A follow-up contact member configured to be able to change following the change of the part to be processed is provided.

In one embodiment, the support device further includes an abutting unit, and the fixed abutting member and the follow-up abutting member do not directly abut against the workpiece, but are in the vicinity of the work piece portion of the workpiece via the abutting unit. Abut. Abutment unit includes a swing lever swingably supported at one end, is composed of a support pin provided on the other end of the swing lever, pivoting the fixed contact member and the follower abutment member The support pin is in contact with the moving lever, and the support pin is in contact with the vicinity of the part to be processed of the workpiece.

  In addition, in order to solve the above-mentioned problem, the method of suppressing the chatter vibration of the workpiece at the time of workpiece machining according to the present invention is a method of following contact from a predetermined direction in the amplitude direction of chatter vibration generated in the workpiece in the vicinity of the workpiece workpiece. The member is brought into contact with a predetermined pre-load, and then the fixed contact member is brought into contact with the vicinity of the workpiece portion from the same direction as the follow-up contact member while maintaining this pre-load. Fix in fixed position. Then, during machining of the workpiece, the follow-up contact member is caused to follow the change of the workpiece part, and the follow-up contact member always has a contact pressure in the vicinity of the workpiece part of the workpiece during machining of the workpiece. Keep in contact with the condition.

  In one embodiment, the fixed contact member and the follow-up contact member are supported so as to be swingable on one end side, and a swing lever having a support pin that contacts the vicinity of the workpiece portion on the other end side. The swing lever swings during machining of the workpiece, and the contact between the support pin and the vicinity of the workpiece portion of the workpiece is maintained.

In the present invention, a fixed support unit and a follow-up support unit are provided, and the follow-up support unit applies a preload to the vicinity of the work portion of the workpiece to cause minute elastic deformation, and this elastic deformation is returned by the fixed support unit. Blocking. Thereby, the resistance to chatter vibration generation that would be attracted during processing can be increased in advance. Furthermore, while the processed portion of the workpiece is displaced in a direction away from the fixed support unit, indirect contact member of the follow-up unit through a support pin for direct or abutting units, always be processed portion of the workpiece Since the contact is maintained with the contact pressure in the vicinity, minute chatter vibration is suppressed. As a result, it is possible to perform processing with high processing efficiency and high processing accuracy without reducing the processing speed.

The present invention is particularly suitable for machining a workpiece that has a complicated shape and cannot clamp the vicinity of the portion to be machined. In this case, there is a sufficient effect not only when the workpiece is thin, but also when the workpiece is sufficiently thick. That is, even in the case of a compact workpiece, chatter vibration is likely to occur as the machining speed is increased, but this can be sufficiently suppressed by employing the method and apparatus according to the present invention. Therefore, it becomes possible to process at a higher processing speed than before.

  Hereinafter, embodiments of the present invention will be described, but the scope of the present invention is not limited to the embodiments described below.

  FIG. 3 is a diagram showing the top surface of one vertical wall L of a thin-walled box-shaped workpiece W using the workpiece support device 31 according to the embodiment of the present invention, as described with reference to FIGS. It is a schematic structure top view which shows the case where it grinds with the tool which is not shown.

The work support device 31 includes two support units, one of which is a fixed support unit 33. The fixed support unit 33 is basically of the same type as the support used in the conventional method described with reference to FIGS. That is, the shaft 37 can be protruded from the casing 35 by a desired length, and the shaft 37 can be fixed at the fixing position. Since the example has been described with reference to FIG. 2, detailed description thereof is omitted here.

  Reference numeral 41 denotes a follow-up support unit. In the present embodiment, a hydraulic cylinder device 42 is used. As the hydraulic cylinder device 42, a known one can be used, and it is not necessary to have a specific configuration for the present invention.

As shown in FIG. 4, the hydraulic cylinder device 42 is housed in the cylinder 43, the cylinder 43, is in liquid-tight contact with the inner wall of the cylinder 43, and is movable in the axial direction. A rod 47 having one end fixed and the other end protruding out of the cylinder 43 is schematically configured. Reference numerals 51 and 53 denote ports that communicate with working chambers 48 and 49 defined on both sides of the piston 45 in the cylinder 43, respectively, and are connected to a working fluid supply source (not shown). The supply of the working fluid to the working chambers 48 and 49 is controlled by a control device (not shown). In the present embodiment, as shown in the figure, the fixed support unit 33 and the follow-up support unit 41 are arranged such that their shafts 37 and rods 47 face in the same direction and extend in parallel.

Reference numeral 55 denotes a contact unit, which includes a swing lever 57 that is swingably mounted around a fulcrum 59, and a support pin 61 that extends in a direction substantially orthogonal to the lever 57 is connected to a free end portion thereof. It is attached using a pin 63. In this case, when the connecting pin 63 is fixed to the support pin 61, the hole into which the connecting pin 63 is formed in the lever 57 is formed in a vertically long shape in the axial direction, so that the lever 57 can move with respect to the swinging motion. The support pin 61 can be linearly moved without any trouble. Reference numeral 65 is a guide for guiding the straight movement of the support pin 61.

  Next, a method for supporting the workpiece W using the workpiece support device 31 will be described. The workpiece W is fixed to the base of the machine tool by an appropriate clamping device (not shown) as in the conventional example. The support device 31 is also arranged and fixed on the base of the machine tool in a predetermined positional relationship with the workpiece W. In this case, the fixed support unit 33, the follow-up support unit 41, and the contact unit 55 may be arranged in a predetermined positional relationship with each other in advance to be unitized, and may be fixed in that state. The arrangement may be fixed by the positional relationship.

The workpiece W is fixed by a clamp so as to be in a position of L0 indicated by a two-dot chain line in FIG. First, the hydraulic pressure is supplied to the hydraulic cylinder device 42 of the follow-up support unit 41 with respect to the workpiece W arranged at this position, and the rod 47 is moved to the left in the figure for a predetermined distance, and the tip of the hydraulic pressure is applied to the swing lever 57. Make contact. In this case, press the rocking levers 57 at a preset pressure, so that to displace the workpiece portion near the vertical wall L of the workpiece W to a position L1 shown in solid line in the drawing. That is, a slight preload is applied to this portion to cause a slight elastic deformation. The hydraulic cylinder 42 is controlled by the control device so as to maintain the state where the preload is applied.

  Next, the shaft 37 of the fixed support unit 33 is moved as described in the conventional example, and is fixed at a position where the tip of the shaft 37 contacts the swing lever 57. By fixing the shaft 37 in this way, the rocking lever 57, and hence the part to be processed of the workpiece W, cannot move to the right from the position indicated by the solid line in the drawing. Thus, if a preload is applied in advance to cause minute elastic deformation in the workpiece W, resistance to a force applied during processing increases, and accordingly chatter is less likely to occur during processing.

Thus, the preparation work is completed, and the machining work is started in this state. When the upper surface S of the vertical wall L is machined, the vicinity of the part to be machined of the workpiece W is reciprocated between a position L1 indicated by a solid line and a position L2 indicated by a broken line in the drawing. At this time, when the workpiece portion L of the workpiece is displaced, this is detected via the support pin 61, and the hydraulic pressure in the working chambers 48 and 49 is appropriately controlled by the control device, whereby the piston 45 is displaced. In this way, the support pin 61 is displaced by following the action of the piston follow-up support unit 41, and the support pin 61 keeps contact with the workpiece L while maintaining a predetermined contact pressure. . As described above, since the support pin 61 is kept in contact with the workpiece portion L of the workpiece W, higher-order chatter vibration with small displacement is suppressed. When the processed portion L is on the left side of the position L1, the shaft 37 of the fixed support unit 33 is separated from the swing lever 57, but the processed portion L and the swing lever 57 are moved to the right side from the positions indicated by the solid lines. Displacement is prevented by this fixed shaft 37.

It is a whole structure perspective view which shows the support method of the conventional workpiece | work. It is sectional drawing of a support. It is a schematic configuration plan view showing an example using a work support device according to an embodiment of the present invention. It is a schematic structure sectional view of a hydraulic cylinder device used for a following support unit.

Explanation of symbols

31 Work support device 33 Fixed support unit 35 Casing 37 Shaft 41 Following support unit 42 Hydraulic cylinder device 43 Cylinder 45 Piston 47 Rod 48, 49 Working chamber W Work L One of the vertical walls of the work (worked part)

Claims (2)

A workpiece chatter vibration suppressing method for suppressing chatter vibration of the workpiece when machining the workpiece using a machine tool,
Prior to machining the workpiece, a predetermined preload is applied to the workpiece by the following support unit, and when the deformation of the workpiece due to the preload is stopped, the fixed support unit is moved to a position where the deformation of the workpiece is prevented from returning. A method for suppressing chatter vibrations of a workpiece, characterized in that the state in which the follow-up support unit applies a preload to the workpiece is continued while the workpiece is moved to fix the fixed support unit . When machining a workpiece using a machine tool, a workpiece support device that suppresses chatter vibration of the workpiece by bringing a contact member into contact with the workpiece,
A follow-up support unit that is movable so that the contact member always contacts the workpiece with a predetermined preload;
Before processing the workpiece, when the workpiece to which the preload is applied by the contact member is stopped at a predetermined stop position, the workpiece is moved in the same direction as the movement direction of the following support unit, and the workpiece is A fixed support unit that prevents movement from a stop position in a direction opposite to the moving direction of the contact member;
A workpiece support device comprising:

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