JP2008062305A - Cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool having a vibration damping function to achieve high-accuracy machining by suppressing the vibration when it is rotated around the axis line to cut a workpiece. <P>SOLUTION: The cutting tool is equipped with a cutting blade on a tool body 1 having an approximately round shape in an opposed view from the tip end side in the direction of an axis line O1, and cuts the workpiece by thrusting the cutting blade into the workpiece while rotating around the axis line O1. A hollow part 11 is formed on the concentric circle around the axis line O1 in the inside of the tool body 1, and a weight member 13 having a connection part 13a fixed to an inner wall surface 21 of the hollow part 11 is disposed so as to have a clearance between the inner wall surfaces 17a, 21 of the hollow part 11 at symmetrical positions about the axis line O1 in the hollow part 11 and a viscous fluid 15 is filled in the clearance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention includes a cutting edge portion provided on the distal end side of a tool body that exhibits a substantially circular shape when viewed from the distal end side in the axial direction, and a cutting function provided with a vibration damping function that rotates around the axial line to cut a workpiece. Related to tools.

  Conventionally, for example, a pin mirror cutter is used as a cutting tool for processing a crankshaft of a reciprocating internal combustion engine. This pin mirror cutter is formed in an annular shape having a substantially circular annular shape as viewed from the front end side in the axial direction, and a plurality of chips are arranged radially on the inner peripheral side from the inner peripheral surface. And a cutting edge portion provided in a state of projecting into the shape. In the pin mirror cutter configured in this way, the cutting edge portion is detachably mounted on the tip end side in the axial direction while coaxially arranging each other on the inner periphery of the tool body, and is integrated with the tool body. (For example, refer to Patent Document 1).

The pin mirror cutter with this cutting edge part mounted integrally with the tool body is mounted with the axial rear end of the tool body axially arranged on the rotating spindle of the processing machine when the crankshaft is processed. The crankshaft (workpiece) is inserted into the inner hole of the pin mirror cutter, that is, the inner hole communicating with the tool body formed in an annular shape and the cutting edge portion, and is mounted on the processing machine. Then, the pin mirror cutter is rotated about the axis by the rotation spindle of the processing machine and revolved with respect to the crankshaft, so that the cutting edge of the tip protruding radially inward of the cutting edge is cut into the crankshaft. It is possible to process the crankshaft into a predetermined shape.
JP-A-8-118125

  However, in the above pin mirror cutter, the main component force and the back component force at the time of cutting are used for machining while rotating around the axis while revolving with respect to the crankshaft and moving back and forth in the axis direction. In some cases, vibration is easily generated by the feed force, and it is difficult to process the crankshaft with high accuracy. In addition, particularly when such vibration occurs, there is a problem that a large cutting sound is generated during cutting.

  In view of the above circumstances, an object of the present invention is to provide a cutting tool having a vibration control function that enables high-accuracy machining by suppressing vibrations when cutting a workpiece by being rotated around an axis. To do.

  In order to achieve the above object, the present invention provides the following means.

  The cutting tool of the present invention includes a cutting blade portion in a tool body that has a substantially circular shape when viewed from the front end side in the axial direction, and cuts the cutting blade portion into a work piece while rotating about the axis. A cutting tool for cutting a workpiece, wherein a hollow portion is formed on a concentric circle centered on the axis inside the tool body, and a symmetrical position on the concentric circle about the axis in the hollow portion The weight member having a connecting portion fixed to the inner wall surface of the hollow portion is disposed with a gap between the inner wall surface of the hollow portion, and the gap is filled with a viscous fluid. It is characterized by being.

In this cutting tool, in the hollow portion formed on the outer peripheral side of the tool body, a dynamic vibration is absorbed by a weight member and a viscous fluid arranged in a symmetrical position on a concentric circle around the axis, that is, a rotationally symmetric position around the axis. Since the tool is configured, when cutting the workpiece while rotating the cutting tool around the axis, when a force that causes vibration is applied to the cutting tool, the vibration of the cutting tool is attenuated and absorbed. be able to.
Specifically, when vibration is generated in the cutting tool, the weight member constituting the mass element and the spring element of the dynamic vibration absorber has a fixed end at the connecting portion fixed to the inner wall surface of the hollow portion. Thus, the vibration of the cutting tool can be absorbed by performing the vibration of substantially opposite phase. The vibration of the weight member is transmitted to the viscous fluid that forms the damping element of the dynamic vibration absorber and is attenuated. Finally, the vibration energy of the weight member is gradually converted into heat energy and dissipated, thereby reducing the vibration of the cutting tool. Can be suppressed.

Moreover, in the cutting tool of this invention, it is desirable that the constriction part is formed in the said connection part.
In this case, the constricted portion can function as a spring element of the dynamic vibration absorber, and the other part of the weight member excluding the connecting portion can function as the mass element of the dynamic vibration absorber. The vibration of the weight member is easily excited. In addition, the natural frequency in the dynamic vibration absorber can be easily set in a wide range, and can be applied to a tool body having various natural frequencies.

Furthermore, in the cutting tool of this invention, the said weight member may be arrange | positioned so that it may extend in the radial direction of the said tool main body from the said connection part.
In this case, since the weight member is likely to vibrate in the axial direction, vibration in the axial direction of the tool body can be particularly suppressed.

  According to the present invention, the vibration of the cutting tool is absorbed by the weight member arranged at the symmetrical position on the concentric circle with the axis as the center in the hollow portion formed on the outer peripheral side of the tool body, and the vibration of the weight member is absorbed. By damping with a viscous fluid, the vibration of the cutting tool can be suppressed. Therefore, it is possible to provide a cutting tool having a vibration damping function that enables highly accurate machining.

  Hereinafter, a cutting tool according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. The present embodiment relates to an internal pin mirror cutter (cutting tool) for machining a crankshaft of a reciprocating internal combustion engine.

  As shown in FIGS. 1 to 3, the pin mirror cutter A of the present embodiment is formed in an annular shape with an adapter (tool main body) 1 having an annular shape in an opposing view from the front end 1a in the axis O1 direction. A plurality of inserts 2 are formed on the inner peripheral side with a cutting blade portion 3 that is detachably provided with the cutting blade protruding radially inward from the inner peripheral surface.

  The adapter 1 is formed of steel (for example, SNCM439, SCM440, etc.). The adapter 4 and the cutting blade are fixed to the flange portion 4 formed on the inner peripheral side and the cutting blade portion 3 provided on the flange portion 4. A plurality of key grooves 5 and a clamper 6 for integrating the portion 3, a plurality of screw holes 7 for fixing the adapter 1 to the processing machine, and a dynamic vibration absorber 8 provided on the outer peripheral side. It is configured.

  The flange portion 4 has a portion located slightly on the outer peripheral side from the inner peripheral edge of the front end surface (front end) 1a orthogonal to the axis O1 of the adapter 1 and is recessed toward the rear end surface (rear end) 1b over the entire periphery. Is formed.

  The key groove 5 has a projection 9 formed on the outer peripheral side of the cutting blade portion 3 to be fitted to restrict movement of the cutting blade portion 3 in the circumferential direction. The key groove 5 is substantially rectangular when viewed from the tip 1a side. It is formed to be recessed from the front end surface 1 a to the rear end surface 1 b while exhibiting a shape, and extends from the end portion on the radially outer side of the flange portion 4 toward the radially outer side. That is, the key groove 5 is formed to include a pair of inner wall surfaces 5a facing in the circumferential direction, an inner wall surface 5b facing the inner side in the radial direction, and a bottom surface 5c facing the tip 1a side. It is recessed so that it may open to the front-end | tip 1a side. Of the pair of inner wall surfaces 5a facing each other in the circumferential direction, one inner wall surface 5a facing the rear side in the rotational direction (arrow T direction) of the adapter 1 gradually becomes the other inner wall surface as it goes from the front end 1a to the rear end 1b. It is formed so as to incline toward the 5a side. Further, the other inner wall surface 5a and the inner wall surface 5b facing radially inward are both extended in parallel to the axis O1. The plurality of key grooves 5 (eight in this embodiment) formed in this way are arranged in parallel at a constant interval in the circumferential direction.

  The clamper 6 is formed so that a part of the outer periphery is cut out in a straight line shape so as to have a substantially half-moon shape, and a through hole is provided at the center of the arc. The clamper 6 is disposed in the circumferential direction of the adapter 1 and can be rotated via a bolt inserted into a through hole in a seat portion 10 recessed in a substantially half-moon shape provided one by one between adjacent key grooves 5. Is seated.

  The dynamic vibration absorber 8 is configured by providing a weight member 13 and a viscous fluid 15 in a hollow portion 11 formed inside the outer peripheral edge of the adapter 1 and sealed outward. The hollow portion 11 is formed on a concentric circle with the axis O1 as the center. The hollow portion 11 is open on the front end surface 1a of the adapter 1 and is recessed toward the rear end 1b. It is comprised with the annular cover body 19 which obstruct | occludes a part. On the radially inner side of the recess 17, a step surface 21 that protrudes from the bottom surface 17 a of the recess 17 that faces the lid 19 and faces the lid 19 extends in the circumferential direction and is formed in an annular shape. The lid 19 is fitted into the recess 17 with its outer peripheral edge coinciding with the outer peripheral edge of the adapter 1 when viewed from the front end 1a side, and is fixed to the front end 1a of the adapter 1 with a bolt. Then, an O-ring, a ring-shaped packing or the like is attached to the outer peripheral surface and the inner peripheral surface of the lid body 19, thereby sealing the opening of the concave portion 17. Further, the lid body 19 is provided with a plug 23 for supplying or replacing the viscous fluid 15 to the hollow portion 11 without removing the lid body 19.

The weight member 13 is formed in an annular shape having a concentric circle centered on the axis O <b> 1 with the same steel as the adapter 1, for example, and is disposed on the bottom surface 17 a of the concave portion 17 forming the inner wall surface of the hollow portion 11. On the inner periphery of the weight member 13, an annular connecting portion 13a extending radially inward to the stepped surface 21 forming the inner wall surface of the hollow portion 11 is integrally formed at the central portion in the axis O1 direction. In the portion 13a, a constricted portion 13b constricted in the direction of the axis O1 is formed. The weight member 13 is formed in a cross-sectional square shape having a longer length in the axis O1 direction and a width in the radial direction than the connecting portion 13a and the constricted portion 13b on the outer peripheral side of the constricted portion 13b. The center of gravity is positioned.
The connecting portion 13a excluding the constricted portion 13b is fixed to the step surface 21 with a bolt. In this fixed state, the weight member 13 excluding the fixing portion of the connecting portion 13a is a recess including the bottom surface 17a and the step surface 21. It arrange | positions through the clearance gap between the inner wall surface of the hollow part 11 which consists of the inner surface of 17 and the inner surface of the cover body 19 facing the recessed part 17. FIG. That is, the weight member 13 is disposed so as to extend outward in the radial direction of the adapter 1 with the connecting portion 13a fixed on the radially inner side of the hollow portion 11 as a starting point.

The viscous fluid 15 is sealed in the hollow portion 11 and filled in a gap between the weight member 13 and the inner wall surface of the hollow portion 11. As the viscous fluid 15, it is desirable to use a liquid having low compressibility such as oil, and examples thereof include Bonnock (registered trademark) M320 (dynamic viscosity 320 cSt (mm ² / s)) manufactured by Nippon Oil Corporation.

  As shown in FIG. 3, the cutting blade portion 3 has a pin blade for processing the outer peripheral surface of the pin portion of the crankshaft on the inner peripheral side of the annular body portion 25 and a side surface of the counterweight portion of the crankshaft. A plurality of inserts 2 having cutting edges as wave blades for processing are detachably attached.

  Further, on the outer peripheral side of the main body portion 25, a substantially annular flange portion 27 protruding to the outer peripheral side in the radial direction of the main body portion 25 is formed on the entire peripheral portion on the rear end side. A plurality of (for example, four or more) protrusions 9 having a substantially rectangular parallelepiped shape protruding outward in the radial direction are disposed at substantially equal intervals in the circumferential direction. Here, of the pair of side surfaces 9a and 9b facing the circumferential direction of each protrusion 9, one side surface 9a facing the front side in the rotational direction (arrow T direction) is gradually rearward in the rotational direction toward the rear end from the front end 3a. It is formed so as to be inclined to the side.

  The adapter 1 and the cutting blade portion 3 configured as described above are integrated by inserting the cutting blade portion 3 on the inner peripheral side of the adapter 1 while arranging the axes O1 and O2 on the coaxial line. At this time, the flange portion 27 of the cutting blade portion 3 is received by the flange portion 4 of the adapter 1, and the plurality of protrusions 9 formed on the cutting blade portion 3 are respectively fitted in the key grooves 5 of the adapter 1. In addition, the pair of side surfaces 9 a and 9 b of each protrusion 9 and the pair of inner wall surfaces 5 a facing each other in the circumferential direction of each key groove 5 are in surface contact with each other, so that the cutting edge portion 3 is axially O 1 with respect to the adapter 1. In addition to being positioned in the direction, it is fixed in the circumferential direction with respect to the adapter 1, and the axis O <b> 2 of the cutting edge 3 is made to coincide with the axis O <b> 1 of the adapter 1. Then, the cutting blade portion 3 inserted in this manner rotates the plurality of clampers 6 and the tip 3 a is pressed, and is firmly held on the inner peripheral side of the adapter 1.

  Next, a method for machining the crankshaft using the pin mirror cutter A having the above-described configuration will be described, and the operation and effect of the pin mirror cutter A of the present embodiment will be described.

  When processing a crankshaft using the pin mirror cutter A of the present embodiment, first, a bolt is inserted into the screw hole 7 of the adapter 1 to which the cutting blade portion 3 is attached, and the bolt is processed (not shown). The pin mirror cutter A is attached to the processing machine by fastening to the screw hole of the spindle of the machine. At this time, the pin mirror cutter A is mounted on the processing machine so that the crankshaft held at both ends by the pair of chucks is inserted into the inner hole of the pin mirror cutter A.

  Next, the insert 2 attached to the inner peripheral side of the cutting edge portion 3 is driven by driving the processing machine to rotate the pin mirror cutter A around the axes O1 and O2 and revolve around the axis of the crankshaft. Cut the crankshaft into the crankshaft.

When vibration occurs in the pin mirror cutter A due to the cutting resistance generated during the cutting process, that is, the main component force, the back component force, and the feed component force acting on the pin mirror cutter A, the mass element of the dynamic vibration absorber 8 And the weight member 13 constituting the spring element resonates, and the vibration of the phase substantially opposite to the vibration of the pin mirror cutter A is started with the fixed portion of the connecting portion 13a fixed to the stepped surface 21 of the hollow portion 11 as a fixed end. Specifically, the constricted portion 13 b bends as a spring element of the dynamic vibration absorber 8, so that other portions of the weight member 13 except the connecting portion 13 a vibrate as mass elements of the dynamic vibration absorber 8.
The vibration of the weight member 13 is transmitted to the viscous fluid 15 that forms the damping element of the dynamic vibration absorber 8 and is attenuated. Finally, the vibration energy of the weight member 13 is gradually converted into thermal energy and dissipated. The vibration of the mirror cutter A can be suppressed.

  According to the pin mirror cutter A according to this embodiment, the vibration of the pin mirror cutter A is absorbed by the weight member 13 having an annular shape concentrically around the axis O1, and the vibration of the weight member 13 is absorbed by the viscous fluid. The vibration of the pin mirror cutter A can be suppressed by attenuating with 15. Therefore, it is possible to provide the pin mirror cutter A having a vibration damping function that enables high-precision processing.

  Further, since the constricted portion 13b is formed in the connecting portion 13a of the weight member 13, the constricted portion 13b functions as a spring element of the dynamic vibration absorber 8, and other portions of the weight member 13 excluding the connecting portion 13a are used. It can be made to function as a mass element of the dynamic vibration absorber 8, and the neck portion 13 b is bent to easily excite the vibration of the weight member 13. Moreover, the natural frequency of the dynamic vibration absorber 8, that is, the equivalent mass of the weight member 13 and the spring constant can be easily set in a wide range, and applied to the adapter 1 having various natural frequencies. Can do.

  Furthermore, since the weight member 13 is disposed so as to extend outward in the radial direction of the adapter 1 with the connecting portion 13a fixed inside in the radial direction of the hollow portion 11 as a starting point, the weight member 13 easily vibrates in the direction of the axis O1. Thus, the vibration in the direction of the axis O1 of the adapter 1 can be particularly suppressed.

As mentioned above, although embodiment of the cutting tool which concerns on this invention was described, this invention is not limited to the said embodiment, In the range which does not deviate from the meaning, it can change suitably.
For example, in the present embodiment, the weight member 13 is fixed in the hollow portion 11 so that the connecting portion 13a is fixed radially inward of the hollow portion 11 and extends outward in the radial direction of the adapter 1 from the connecting portion 13a. However, the present invention is not limited to this, and the connecting portion 13a is fixed to the outer side in the radial direction of the hollow portion 11 and is arranged so as to extend inward in the radial direction of the adapter 1 starting from the connecting portion 13a. It doesn't matter.

  The weight member 13 is formed in an annular shape, but is not limited to this. For example, the connecting portion 13a of the weight member 13 is formed in an annular shape, and other weight members 13 other than the connecting portion 13a are formed. A part may be divided | segmented and formed in the circumferential direction. Further, for example, the constricted portion 13b of the connecting portion 13a may be formed by being divided in the circumferential direction together with other portions of the weight member 13. Furthermore, for example, the entire weight member 13 including the connecting portion 13a may be divided in the circumferential direction. However, it is desirable that the divided portions of the weight member 13 are arranged at equal intervals in the circumferential direction. In other words, it is desirable to arrange them at rotationally symmetric positions by a predetermined angle on a concentric circle with the axis O1 as the center.

As described above, when a part or the whole of the weight member 13 is divided into a plurality of parts, the weight member 13 is more likely to vibrate, and thus the vibration of the adapter 1 can be more reliably suppressed. .
As described above, when the weight member 13 is divided, the hollow portion 11 may be formed in the circumferential direction in accordance with this. Further, as described above, when the constricted portion 13b is divided, each constricted portion 13b may be formed not only in the direction of the axis O1 but also in the circumferential direction.

Furthermore, in this embodiment, although the cutting tool was demonstrated as what is what is called an internal type pin mirror cutter A with which the cutting-blade part 3 is mounted | worn on the inner peripheral side of the adapter 1, and is used for the process of a crankshaft. However, the present invention is not limited to this, and the present invention is applied to a so-called external pin mirror cutter in which a cutting edge portion is mounted on the outer peripheral side of the adapter 1 or a face mill for performing planar processing of a workpiece. It may be done.
In addition, the cutting tool applied to the present invention is not limited to the configuration in which the substantially circular cutting edge portion 3 is mounted on the adapter 1 as in the present embodiment. For example, each cutting edge is cut into the tool body. It may be configured to be directly mounted as a blade portion, or may be configured to integrally form the cutting blade on a tool body.

It is a front view which shows the tool main body of the cutting tool which concerns on one Embodiment of this invention. FIG. 2 is a view taken along line XX in FIG. 1. It is a front view which shows the cutting blade part of the cutting tool which concerns on one Embodiment of this invention.

Explanation of symbols

1 Tool body (Adapter)
1a Tip (tip surface)
3 Cutting edge part 11 Hollow part 13 Weight member 13a Connection part 13b Constriction part 17a Inner wall surface (bottom face)
21 Inner wall surface (step surface)
A Cutting tool (pin mirror cutter)
O1, O2 axis T rotation direction

Claims (3)

Cutting in which a tool body having a substantially circular shape when viewed from the front end side in the axial direction is provided with a cutting edge portion, and the workpiece is cut by cutting the cutting edge portion into the work piece while rotating around the axis. A tool,
Inside the tool body, a hollow portion is formed on a concentric circle centered on the axis,
A weight member provided with a connecting portion fixed to the inner wall surface of the hollow portion has a gap between the inner wall surface of the hollow portion at a symmetrical position on the concentric circle centered on the axis in the hollow portion. A cutting tool which is arranged and the gap is filled with a viscous fluid.   The cutting tool according to claim 1, wherein a constricted portion is formed in the connecting portion.   The cutting tool according to claim 1, wherein the weight member is disposed so as to extend in a radial direction of the tool main body with the connecting portion as a starting point.

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