JP5728824B2 - Tool chatter prevention device - Google Patents

Description

  The present invention relates to a chatter preventing device for a tool used for suppressing chatter vibration generated in a tool in a machine tool.

  One of cutting tools used for lathes and the like is a boring bar called an inner diameter machining tool. Since this boring bar is used in the shape of a cantilever beam that is overhanged from a tool support such as a tool holder, vibration called chatter vibration is likely to occur depending on cutting conditions, resulting in a problem of reduced machining accuracy. .

  As a countermeasure against the chatter vibration, a proposal has been made to absorb vibration energy that causes chatter vibration by using friction damping. For example, Patent Document 1 is a configuration in which a friction damper is movably provided inside a bolt member that connects a tool support and a cutting tool, and the friction damper is pressed against a cap that is a contact target. The friction damper part vibrates at a phase different depending on the inertia with respect to the vibration of the tool, and the vibration energy of the cutting tool is absorbed by the sliding friction between the friction damper part and the cap part. In Patent Document 1, the friction damper portion is pressed against the cap portion by magnetic force, but may be pressed by an elastic biasing force such as a spring. In Patent Document 2, a weight is attached to a cutting tool via an elastic body, and the vibration energy of the cutting tool is absorbed by friction damping in the elastic body.

Japanese Patent Laid-Open No. 2007-210088 Japanese Utility Model Publication No. 1-1117803

  As in Patent Document 1, the frictional force is generated by using the inertial force of the friction damper part. In order to obtain the necessary frictional force, the mass of the friction damper part must be considerably increased. It is difficult to incorporate into an actual tool support or cutting tool. Further, when adjusting the magnetic force or the elastic biasing force that presses the friction damper portion against the cap portion according to the magnitude of the vibration energy, it is necessary to replace the magnet and spring parts. Therefore, a plurality of magnets and springs having different magnetic forces or elastic urging forces must be prepared, and fine adjustment is difficult.

  As in Patent Document 2, providing a vibration-proof mechanism for preventing chatter vibration in the cutting tool itself is a dedicated cutting tool, and the cutting tool becomes expensive. Moreover, since a commercially available cutting tool cannot be used, versatility is low.

An object of the present invention is to prevent chatter vibration generated in a tool, easily adjust according to the magnitude of vibration energy that causes chatter vibration, and can be applied to a commercially available tool. Is to provide.
Another object of the present invention is to make it possible to finely adjust the frictional force in the direction of resistance to vibration generated in the tool.
Still another object of the present invention is to provide a structure having high rigidity in the direction in which the frictional force acts and strong resistance to the frictional force.
Still another object of the present invention is to provide a simple structure.

  The tool chatter preventing device of the present invention is a tool chatter preventing device used for a machine tool, and is an apparatus main body that is attached to a tool support and disposed on the outer periphery of a tool attached to the tool support, A contact member that is brought into contact with the tool so that a frictional force is generated in a direction that resists vibration generated in the tool during processing, and the contact member is pressed against the tool, and the pressing force can be adjusted. And a pressing force adjusting mechanism. The “tool support” here refers to a tool holder or a tool post.

  According to this configuration, the contact member is pressed against the tool by the pressing force adjusting mechanism. Thereby, a frictional force is generated between the tool and the contact member in a direction that becomes resistance to vibration generated in the tool during processing. The vibrational energy that causes chatter vibration is absorbed by the frictional damping due to this frictional force. By adjusting the pressing force for pressing the contact member against the tool with the pressing force adjusting mechanism so as to obtain an appropriate frictional damping, vibration energy can be eliminated and chatter vibration can be suppressed.

Contact portion between the tool before Symbol contact member, Ru elastically deformable der in a direction which is pressed against the tool by the pressing force adjusting mechanism.
If the contact portion of the contact member can be elastically deformed in the direction in which the tool is pressed, the frictional force can be generated in a wide range of the pressing force by the pressing force adjusting mechanism. That is, the change in the magnitude of the frictional force is smaller than the change in the magnitude of the pressing force. Therefore, it is easy to finely adjust the frictional force by changing the pressing force. However, if the elastic deformation is too easy, a frictional force is not generated even if a pressing force is applied, so that the contact portion is set to be elastically deformed appropriately.

The direction in which the frictional force is generated is a tangential direction at the contact point of the contact portion in the outer peripheral surface portion of the tool having a circular cross section. The contact member includes the contact portion and a main portion that supports the contact portion, and the contact portion is pressed against the tool via a slit extending in a direction in which the frictional force acts on the main portion. spaced in a direction that is shall be the linked shape to said main portion at the junction of the end of the slit. The direction in which the friction force acts is the direction in which the friction force is generated. When the contact member has the above shape, the thickness of the contact portion in the direction in which the friction force acts is thin, so the rigidity in the direction intersecting the direction in which the friction force acts is low, and moderate elasticity is achieved by the pressing force by the pressing force adjusting mechanism. Deformation can occur. On the other hand, since the contact portion is long in the direction in which the frictional force acts, the rigidity in the same direction is high and the resistance to the frictional force is strong.

In this invention, it is preferable that the pressing force adjusting mechanism has a function of adjusting a force of pressing the contact member against the tool and a function of attaching the contact member to the apparatus main body.
By providing the pressing force adjusting mechanism with a function of attaching the contact member to the apparatus main body, there is no need to separately provide a member for attaching the contact member to the apparatus main body, and the configuration of the chattering prevention device can be simplified.

  The tool chatter prevention device of the present invention is used for a machine tool, and is attached to a tool support and disposed on the outer periphery of a tool mounted on the tool support, A contact member that is brought into contact with the tool so that a frictional force is generated in a direction that resists vibration generated in the tool, and a pressing force adjusting mechanism that presses the contact member against the tool and adjusts the pressing force. Therefore, chatter vibration generated in the tool can be suppressed, adjustment according to the magnitude of vibration energy that causes chatter vibration is easy, and it can be applied to a commercially available tool with high versatility.

Contact portion between the tool in the contact member, because the direction to be pressed against the tool by the pressing force adjustment mechanism which is elastically deformable, fine adjustment of the frictional force in a direction to be resistant to vibration generated in the tool Is possible.

The contact member includes the contact portion and a main portion that supports the contact portion, and the contact portion is pressed against the tool via a slit extending in a direction in which the frictional force acts on the main portion. Since the shape is connected to the main portion at the connecting portion at the end of the slit, the rigidity in the direction in which the frictional force acts is high and the resistance to the frictional force is strong.

  The pressing force adjusting mechanism can have a simple structure when it has a function of adjusting the pressing force of the contact member against the tool and a function of attaching the contact member to the apparatus main body.

It is a front view of the tool support body provided with the tool chattering prevention apparatus concerning one Embodiment of this invention. It is a side view of the tool support. It is a top view of the tool support. It is a partially broken front view of the chattering prevention device. It is a partial top view of the machine tool using the chattering prevention apparatus. It is a front view of the chattering prevention apparatus of the tool concerning different embodiment of this invention. It is a front view of the chattering prevention apparatus of the tool concerning further different embodiment of this invention.

  An embodiment of the present invention will be described with reference to the drawings. 1 to 3 show a tool support provided with the device for preventing chatter of the present invention. The tool support in the figure is a tool holder 1. The tool holder 1 is attached to a turret tool post 42 (FIGS. 1 and 2) of a machine tool such as a lathe, and a tool 30 that is used fixedly to a rotating workpiece is mounted thereon. The tool 30 is, for example, a boring bar that is a tool for internal diameter cutting. The tool 30 has a cutting edge at the tip of the shank portion 30a. The shank portion 30a of the tool 30 has a circular cross-sectional shape. When the tool 30 is directly attached to the tool post, the tool post serves as a tool support.

  The tool holder 1 is attached to the outer peripheral surface of the turret tool post 42 by bolts (not shown) inserted through bolt holes 3 provided at the four corners of the base portion 2. The tool holder 1 has a tool mounting hole 4 which is a circular through hole extending in the Z-axis direction (FIG. 2) that is the direction of the axis of the turret tool post 42, and a sleeve member 31 is placed in the tool mounting hole 4. The base part 30aa of the shank part 30a of the tool 30 is mounted. Specifically, the cylindrical portion 31 a of the sleeve member 31 that fits to the inner periphery of the tool mounting hole 4 is fixed to the tool holder 1 by the sleeve fixing screw 32, and the flange portion of the sleeve member 31 that is located outside the tool mounting hole 4. The base 30aa is fixed to 31b with a tool fixing screw 33. Note that the tool 30 may be directly mounted in the tool mounting hole 4 of the tool holder 1 without using the sleeve member 31.

  A tool chattering prevention device 10 is attached to the end surface of the tool holder 1 on the tool front end side. As shown in FIG. 4, the chatter preventing device 10 includes a device main body 11 disposed on the outer periphery of the shank portion 30 a of the tool 30 mounted on the tool holder 1, and the device main body 11 sandwiching the shank portion 30 a of the tool 30. The contact member 12 is disposed opposite to the contact member 12 and a part of the contact member 12 is brought into contact with the outer peripheral surface of the shank portion 30a of the tool 30. The contact member 12 is attached to the apparatus main body 11, and the contact member 12 is pushed against the shank portion 30a of the tool 30. And a pressing force adjusting mechanism 13 that adjusts the pressing force.

  The apparatus main body 11 and the contact member 12 are both plate materials having the same thickness, and are made of metal, for example, steel. The apparatus main body 11 has a semicircular recess 14 having a radius that allows the shank 30a of the tool 30 to be fitted therein, and the shank 30a of the tool 30 is disposed in the semicircular recess 14.

  The contact member 12 includes a contact portion 15 that is a portion that contacts the tool 30, and a main portion 16 that supports the contact portion 15. The contact portion 15 and the main portion 16 are separated by a slit 17 extending in a tangential direction (X-axis direction) between the contact portion 15 and the tool 30, and a connecting portion 18 that is a peripheral portion at both ends of the slit 17. Are connected to each other. Both end portions 17a of the slit 17 are formed in a circular shape in order to avoid stress concentration. The contact portion 15 is a straight belt, and since the width in the direction (Y-axis direction) perpendicular to the length direction (X-axis direction) of the slit 17 is narrow, the rigidity in the Y-axis direction is low and elastic deformation in the Y-axis direction is achieved. Is possible. On the other hand, since the contact portion 15 is long in the length direction (X-axis direction) of the slit 17, the rigidity in the X-axis direction is high. The Y-axis direction is a direction in which the contact member 12 is pressed against the tool 30 by the pressing force adjusting mechanism 13, and the X-axis direction is a direction in which a frictional force generated by pressing the contact member 12 against the tool 30 acts. A contact point P between the contact portion 15 and the tool 30 is the center in the length direction of the contact portion 15 and is located on a straight line L extending from the center O of the tool 30 in the Y-axis direction.

  The pressing force adjusting mechanism 13 is provided in the apparatus main body 11 and is provided in the adjustment bolt hole 20 that is a through hole extending in the arrangement direction (Y-axis direction) of the apparatus main body 11 and the contact member 12, and the adjustment bolt hole 20 provided in the contact member 12. And the adjustment screw 22 and the adjustment screw 22 located on the same axis. The prepared bolt 22 is inserted from the adjustment bolt hole 20 side, and the screw portion 22 a at the tip of the adjustment bolt 22 is screwed into the adjustment screw hole 21, so that the contact member 12 is attached to the apparatus main body 11. The head 22 b of the adjustment bolt 22 is brought into contact with the peripheral edge of the opening on the side where the adjustment bolt 22 is inserted in the adjustment bolt hole 20. Further, the pressing force for pressing the contact member 12 against the tool 30 is adjusted by adjusting the screwing amount of the adjusting bolt 22 into the adjusting screw hole 21. The direction of the pressing force is a direction orthogonal to the Y-axis direction, that is, the direction in which the frictional force acts. Therefore, the friction force can be efficiently generated by the pressing force of the pressing force adjusting mechanism 13. In the illustrated example, two pressing force adjusting mechanisms 13 are provided on both sides of the tool 30, but the one pressing force adjusting mechanism 13 can be used to attach the contact member 12 to the apparatus main body 11 and adjust the pressing force. May be performed.

  The apparatus main body 11 and the contact member 12 are each provided with a mounting screw insertion hole 23 that penetrates in the thickness direction (a direction orthogonal to the paper surface in FIG. 4). The apparatus main body 11 and the contact member 12 are respectively attached to the tool holder 1 by means of attachment screws 24 (FIGS. 1 to 3) inserted through the attachment screw insertion holes 23. In addition, in the state which attached the apparatus main body 11 and the contact member 12 to the tool holder 1, the internal diameter of the attachment screw penetration hole 23 so that the apparatus main body 11 and the contact member 12 can move to some extent to an X-axis direction and a Y-axis direction. Is larger than the outer diameter of the mounting screw 24.

  FIG. 5 is a partial plan view schematically showing an example of a machine tool using the tool holder 1. The machine tool 40 is a turret lathe and includes a main shaft 41 and a turret tool post 42. The spindle 41 has a spindle chuck 43 at its tip, and is driven to rotate by gripping the workpiece W with the spindle chuck 43. The turret tool post 42 has a rotation center axis parallel to the axis of the main shaft 41, and a horizontal direction perpendicular to the axis of the main shaft 41 and a direction along the axis of the main shaft 41 through a feed table (not shown). It is possible to move in the direction (X-axis direction). The turret tool post 42 is in the form of a polygon whose front shape is a polygon, and a tool 30 is attached to each tool station consisting of a peripheral surface portion between each corner via a tool holder 1. FIG. 5 shows a state where a tool 30 made of a boring bar is attached to one tool station. The tool 30 is attached so as to protrude from the tool holder 1 in a direction parallel to the axis of the main shaft 41 and the rotation center of the turret tool post 42. In the processing of the workpiece W using the tool 30 by the machine tool 40, the inner diameter surface processing of the recess Wa on the tip surface of the workpiece W is performed.

  Since the tool 30 is attached to the tool holder 1 in a cantilever shape, chatter vibration in the cutting direction tends to occur during machining. However, by providing the chatter prevention device 10 in the tool holder 1, the effect of suppressing the chatter vibration can be obtained. The operation and effect of the chattering prevention device 10 will be described in detail.

  By appropriately tightening the adjusting bolt 22 of the pressing force adjusting mechanism 13 into the adjusting screw hole 21, the contact portion 15 of the contact member 12 is pressed against the tool 30. Thereby, a frictional force is generated between the tool 30 and the contact member 12 in a direction (X-axis direction) that becomes resistance to vibration generated in the tool 30. The vibrational energy that causes chatter vibration is absorbed by the frictional damping due to this frictional force. By setting the pressing force that presses the contact member 12 against the tool 30 to an appropriate magnitude that provides frictional damping, vibration energy can be eliminated and chatter vibration can be suppressed. The pressing force can be adjusted by changing the screwing amount of the adjusting bolt 22 into the adjusting screw hole 21.

  Since the contact portion 15 of the contact member 12 can be elastically deformed in the Y-axis direction that is the pressing direction, it is possible to generate a frictional force in a wide range of the pressing force by the pressing force adjusting mechanism 13. That is, the change in the magnitude of the frictional force is smaller than the change in the magnitude of the pressing force. Therefore, it is easy to finely adjust the frictional force by changing the pressing force. On the other hand, since the contact portion 15 of the contact member 12 has high rigidity in the X-axis direction, which is the direction in which the friction force acts, the resistance force against the friction force is strong.

  FIG. 6 shows a chattering prevention device having a different contact member shape from the above example. In the contact member 12 of the chattering prevention device 10, the contact portion 15 and the main portion 16 are connected to each other only by the connecting portion 18 at one end of the slit 17. Even in this shape, it can be elastically deformed in the direction of the pressing force (Y-axis direction), and the rigidity in the direction in which the frictional force acts (X-axis direction) can be appropriately maintained.

  FIG. 7 shows a chattering prevention device in which the shape of the contact member is further different. The contact member 12 of the chattering prevention device 10 separates the contact portion 15 and the main portion 16 in the pressing direction by a circular opening 25. In this case as well, although not reaching the contact member 12 provided with the slit 17 (FIGS. 4 and 6), the effect of elastically deforming the contact portion 15 is obtained.

  In each of the above embodiments, the chattering prevention device provided on a tool support such as a tool holder on which a long tool such as a boring bar is mounted has been described. It is applicable also to the tool support body which mounts the tool of.

1 ... Tool holder (tool support)
DESCRIPTION OF SYMBOLS 10 ... Chatter prevention apparatus 11 ... Apparatus main body 12 ... Contact member 13 ... Pressing force adjustment mechanism 15 ... Contact part 16 ... Main part 17 ... Slit 18 ... Connection part 30 ... Tool

Claims (2)

An apparatus for preventing chatter of a tool used in a machine tool, which is attached to a tool support and disposed on the outer periphery of a tool mounted on the tool support, and vibration generated in the tool during processing A contact member that is brought into contact with the tool so as to generate a frictional force in a direction that causes resistance, and a pressing force adjusting mechanism that presses the contact member against the tool and can adjust the pressing force. The contact portion of the contact member with the tool is elastically deformable in a direction in which the contact force is pressed against the tool by the pressing force adjusting mechanism, and the direction in which the frictional force is generated is determined by the contact at the outer peripheral surface portion having a circular cross section of the tool. The contact member has a contact portion and a main portion that supports the contact portion, and the contact portion is in a direction in which the frictional force is generated with respect to the main portion. Total That through the slit, spaced in a direction which is pressed against the tool, which are connected to the main portion by a connecting portion of the end of the slit, chattering prevention device engineering tools.   The tool chattering prevention device according to claim 1, wherein the pressing force adjusting mechanism has a function of adjusting a force of pressing the contact member against the tool and a function of attaching the contact member to the apparatus main body.