JP7449514B2 - Cutting blade holder for boring - Google Patents

Description

The present invention relates to a cutting blade holder for boring, which is provided in the shape of a rod and has a cutting blade mounting seat part on its tip portion to which a cutting blade in the form of an exchangeable tip for boring is fixed.

Conventionally, cutting blade holders for boring have been equipped with a weight housed in the holder body and a support supported at a distance from the inner surface in order to prevent chatter vibration during cutting in turning tools, especially boring bars. a means for moving the weight relative to the holder body, and a control means for controlling the means, and this control is performed using a detection signal from a sensor that detects the vibration of the head, thereby controlling the drive frequency of the weight, It is possible to control the amplitude, etc., and the vibration of the cutting edge is canceled out by the reaction caused by the weight displacement.Also, by directing the supporting direction of the supporting means and the driving direction of the driving means to the axial direction or radial direction of the holder body, A method has been proposed (Patent Document 1) in which the direction of the reaction caused by the displacement of the weight can be set in various ways.

In addition, as a coolant supply structure for a cutting tool that has a conventional boring cutting blade holder as a component, for example, a head member on which an insert mounting seat for mounting a cutting insert is formed is attached to the tip of the holder. They are removably attached with their mounting surfaces in close contact with each other, and the holder is formed with a coolant hole through which coolant is supplied to the mounting surface, and a hole on the holder side is formed on the mounting surface on the head member side. It has been proposed that a concave groove is formed that communicates with a coolant hole opened in the mounting surface and opens toward the cutting edge of the cutting insert (Patent Document 2). Note that the coolant hole described above has a symmetrical circular cross section and is formed to extend in the central axis direction.

Further, as a coolant supply structure for a cutting tool having a conventional boring cutting blade holder as a component, a cutting tool bottom plate is arranged between a cutting insert and a holder, and is fixed to the holder, The cutting insert includes a flank face and a rake face continuous with the flank face, a ridge line between the flank face and the rake face constitutes a cutting edge, the cutting edge includes an arcuate portion, and the cutting tool bottom plate is provided with a coolant supply path for injecting the coolant supplied from the holder into the circular arc portion, and the coolant supply path has an inlet for introducing the coolant from the holder into the coolant supply path, and an inlet for introducing the coolant into the circular arc portion. It has been proposed that the injection port has an injection port for injecting into the arc portion, and the injection port for the arc portion has a shape curved along the arc portion (Patent Document 3). ing.

Moreover, the above-mentioned bottom plate for a cutting tool can be produced using, for example, a metal 3D printer. Specifically, it has been proposed that a floor plate be produced by heating metal powder with a laser (Patent Document 3).

Japanese Patent Application Publication No. 06-23605 (page 1) Japanese Patent Application Publication No. 2010-105107 (page 1) JP 2018-111205 (Page 1, [0034])

The problem to be solved regarding the cutting blade holder for boring is to avoid self-excited chatter vibration by the geometrical structure of the head of the cutting blade holder for boring, without creating a complicated configuration as in Patent Document 1 mentioned above. The problem is that no method has been proposed that can be used to further suppress the effects and perform cutting with higher precision and quality.

Therefore, the purpose of the present invention is to reduce the weight, increase the natural frequency, and create a structural structure with better vibration isolation, so that it can be used for cutting with higher accuracy and quality. An object of the present invention is to provide a cutting blade holder for boring.

The present invention includes the following configuration to achieve the above object.
According to one embodiment of the cutting blade holder for boring according to the present invention, the cutting blade holder is provided in a rod shape, and the cutting blade mounting seat portion is provided at the tip portion to which a cutting blade in the form of an exchangeable tip for boring is fixed. A cutting blade holder for boring, wherein the tip side portion including the tip portion is formed to have a thinner outer shape than other portions including the rear end portion , and is cut perpendicular to the axis of the rod-shaped shaft center. A hollow section is provided asymmetrically with respect to the cross-sectional shape, which is neither line symmetrical nor point symmetrical, and is provided inside the distal end portion including the distal end section to increase the natural frequency. The cross-sectional shape cut perpendicularly to the axis of the cross-section is asymmetrical, with neither line symmetry nor point symmetry .

According to one embodiment of the cutting blade holder for boring according to the present invention, the hollow portion is a coolant for distributing coolant to a discharge port opened and provided in the tip portion so as to cool the cutting blade. It can be characterized in that it constitutes a part of the flow path.

According to one form of the cutting blade holder for boring according to the present invention, the cavity provided at the tip side portion is provided with a three-dimensional reinforcing structure that supports the outer shell forming the cavity from the inside. The space in the cavity occupied by the three-dimensional reinforcing structure may be a communicating space in which no closed cell-shaped portion is provided.

According to one form of the cutting blade holder for boring according to the present invention, the three-dimensional reinforcing structure may be a gyroid structure.

According to one embodiment of the method for manufacturing a cutting blade holder for boring according to the present invention, there is provided a method for manufacturing a cutting blade holder for boring, wherein the cutting blade holder for boring is manufactured by an outer layer forming the hollow portion. It can be characterized in that the shell is designed by using an optimization design method and formed by laser melting three-dimensional additive manufacturing.

According to the cutting blade holder for boring of the present invention, it is possible to reduce the weight and increase the natural frequency to create a structural structure with better vibration isolation. This has the particularly advantageous effect of being able to carry out cutting operations.

FIG. 1 is a perspective view showing the appearance of an example of a cutting blade holder for boring according to the present invention. It is a perspective view showing the tip part of the example of the form of the cutting blade holder for boring concerning the present invention. FIG. 4 is a vertical cross-sectional view (a vertical cross-sectional view taken along the line AA in FIG. 4) showing an example of the form of the cutting blade holder for boring according to the present invention. It is an explanatory view showing the rear end surface of the example of the form of the cutting blade holder for boring concerning the present invention. FIG. 5 is a vertical cross-sectional view (a vertical cross-sectional view taken along the line BB in FIG. 4) showing an example of the form of the cutting blade holder for boring according to the present invention. FIG. 2 is a cutaway perspective view showing an example of the internal structure of the cavity at the tip of the cutting blade holder for boring according to the present invention. It is a perspective view showing the appearance of an example of the form of the cutting blade holder for boring concerning the present invention seen from another angle. FIG. 2 is a perspective plan view showing an example of the form of a coolant flow path of the cutting blade holder for boring according to the present invention. FIG. 2 is a perspective side view showing an example of the form of a coolant flow path of the cutting blade holder for boring according to the present invention. It is a perspective view seen from the tip side showing an example of the form of a coolant channel of a cutting blade holder for boring concerning the present invention. It is a perspective view showing the tip part of the example of the form in which a cutting blade was attached to the cutting blade holder for boring concerning the present invention. It is a perspective view which shows the other example of the front-end|tip part of the cutting blade holder for boring based on this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a cutting blade holder for boring according to the present invention will be described in detail based on the accompanying drawings (FIGS. 1 to 12).

As shown in FIGS. 1 and 7, the cutting blade holder for boring according to the present invention has a basic configuration in the form of a rod, and has an exchangeable chip-shaped cutting blade 40 for boring at the tip 10a (see FIG. 11). ) is provided with a cutting blade mounting seat 20 to which the cutting blade is fixed. Note that the cutting blade mounting seat portion 20 of this embodiment is provided with a female mounting screw portion 22 (see FIG. 2, etc.), and has a structure in which the cutting blade 40 is fixed by the screw.

In the boring cutting blade holder according to the present invention, the tip portion 10a is formed to have a thinner outer shape than other parts including the rear end portion 30 and is provided asymmetrically about the axis, and the tip portion Inside the distal end portion 10 including 10a, a hollow portion (cavity portion 11) is provided which is asymmetrically formed with respect to the axis so as to increase the natural frequency.

According to the cutting blade holder for boring according to the present invention, the mass reduction (weight reduction) of the tip portion 10a and the asymmetry between the outer shape of the tip portion 10a and the shape of the hollow portion 11 of the tip side portion 10 ( Securing rigidity under a load) can increase the natural frequency and improve vibration isolation. By using the cutting blade holder for boring according to the present invention, self-excited chatter vibration of the cutting edge of the boring tool (cutting tool for boring) can be suppressed in metal boring processing, so that the cutting surface Roughness can be improved and cutting can be performed with higher precision and quality. That is, by increasing the natural frequency of the cutting tool, it is possible to prevent problematic resonance from occurring, and as a result, cutting with higher accuracy and quality can be achieved. Further, by suppressing self-excited chatter vibration of the cutting edge, the life of the cutting edge 40 can be extended.

In the embodiment of the cutting blade holder for boring according to the present invention, as shown in each figure, the external shape of the tip portion 10a is an asymmetrical tapered shape that gradually tapers toward the tip, and a concave portion is formed on the outer surface. However, the shape is such that no gouged portion or recessed portion is formed. The tapered shape of the distal end portion 10a of this embodiment is basically such that its cross-sectional area gradually decreases toward the distal end due to the outer surface shape in which a plurality of concave surfaces and flat surfaces are connected.

In addition, in this embodiment, the size of the outer shape in the direction perpendicular to the axis is increased at least in a portion where the size occupied by the cavity 11 is maximum so that the cavity 11 is asymmetric and has an appropriate size. It is provided so that the length is more than half the length (a ratio of more than 50%). The asymmetrical shape of the tip portion 10a and the hollow portion 11 means that the cross-sectional shape taken perpendicularly to the axis of the rod-shaped holder is at least in terms of both the outer shape and the inner shape. This means that it has neither line symmetry nor point symmetry.

Further, the cavity 11 of this embodiment shown in FIGS. 3 and 5 has a structurally designed shape based on the optimal cavity shape calculated by topology optimization analysis. That is, in order to increase the natural frequency while maintaining rigidity, a shape optimization analysis is performed and a specially shaped cavity 11 is provided inside the tip side. Structural design using topology optimization is a method that proposes how to arrange materials in the space you want to design to create the optimal structure, and through redesign, the shape is modified to take into account other design elements. , designed into the final shape. With this design, the shape of the cavity 11 and the outer shell 12 forming the cavity are asymmetrical, and the thickness of the outer shell 12 is non-uniform. .

In addition, in this embodiment, an optimization analysis is performed on the condition that the mass of the distal end portion 10, which is a predetermined range on the distal end side, is 50%, and the redesign is performed based on the results, and the cavity portion 11 is The structure is designed so that it also serves as a passage (coolant flow path 31) for cutting fluid (coolant). Specifically, in the optimization analysis of this embodiment shown in the figure, a cavity is formed on the side of the distal end portion 10 on which the cutting edge (cutting edge) of the cutting blade 40 protrudes, and on the opposite side with respect to the axis center. Although the open shape opened to the outside and no coolant flow path 31 was formed, it was redesigned and the open shape of the cavity was changed to a closed shape. Therefore, as shown in FIGS. 3 and 5, the wall thickness of the outer shell 12 at the distal end portion 10 opposite to the side where the cutting edge of the cutting blade 40 protrudes is thinner than that at other portions. has been done. By designing in this way, in this embodiment, the natural frequency (resonant frequency) could be increased by 13% compared to the conventional solid structure without the cavity 11.

Further, according to this embodiment, since an appropriate outer shell 12 is provided to form an appropriate cavity 11 in the distal end portion 10, as described above, the vibration damping property is improved by reducing the weight. In addition, it has a geometrical structure that can improve vibration isolation by ensuring high rigidity under a state where a cutting load is applied due to the asymmetry. In other words, the amount of deflection of the boring bar (boring tool) due to the cutting force (load) applied during cutting, which is mainly the amount of deflection (displacement) that occurs in the main body of the holder, can be appropriately measured. The structure has sufficient rigidity to suppress vibration and improve vibration isolation. Furthermore, the cross-sectional shape of the holder of this embodiment is such that the base shape of the tip 10a is such that it can receive the pressure that is applied during cutting when it is mounted on a machine tool (tool chuck section of a cutting device). It is provided so that it has a slightly elongated elliptical shape. According to this, the amount of deflection can be suppressed by increasing the rigidity, and the processing accuracy of cutting can be improved.

Furthermore, in the present invention, by providing the hollow portion 11, the weight of the tip portion 10a can be reduced without providing a hollow portion on the outside of the hollowed-out shape formed on the outer peripheral surface of a conventional solid rod-shaped holder. I'm trying. That is, in the present invention, by appropriately forming the outer shell 12 as described above, it is possible to create a structure that has high rigidity and high load-bearing capacity and durability compared to conventional solid holders. At the same time, the weight reduction of the tip portion 10a improves the vibration damping properties.

Furthermore, in this embodiment, the outer shell 12 forming the cavity 11 is designed using an optimization design method and formed by laser melting three-dimensional additive manufacturing. Laser melting three-dimensional additive manufacturing is modeling using a so-called metal melting 3D printer, and according to this, an asymmetrical and complex optimized shape can be manufactured easily and appropriately. According to a method of simultaneously molding a large number of books using a large 3D printer, manufacturing costs can be reduced. Note that the material of the metal powder can be, for example, maraging steel.

In addition, in this embodiment, the cavity 11 constitutes a part of a coolant flow path 31 for flowing coolant to a discharge port 21 that is opened and provided in the tip portion 10a so as to cool the cutting blade 40. It is set up like this. According to this, the coolant flow path can be suitably formed and sufficient coolant (cutting fluid) can be supplied, so that the accuracy and quality of cutting can be improved, and the cutting blade 40 can be Can extend lifespan.

In this way, in this embodiment, by using a 3D printer, the shape has the hollow part 11 inside, and the flow path (coolant flow path 31) for injecting cutting fluid to the chip (cutting blade 40) can be appropriately configured. is formed. That is, the cavity 11 has a structure that also serves as a part of the cutting fluid flow path, so that the powder material remaining as an unsintered portion after additive manufacturing can be discharged using the cutting fluid flow path. It has become. In order to efficiently discharge chips from the cutting edge of the cutting blade 40, a discharge port 21 is provided so that cutting fluid can be applied from below the cutting edge.

In addition, the shape of the discharge port 21 (cutting fluid exit As shown in the figure, the hole is provided in a long square (rectangular) shape along the cutting edge. Furthermore, in this embodiment, in order to ensure a sufficient opening area for the discharge port 21, the portion where the discharge port 21 is formed is extended outward in the radial direction within a range that does not interfere with the workpiece during cutting. A bulging portion 15 is formed, and a discharge outlet passage portion 31b extending from the cavity portion 11 is provided at the portion where the bulge portion 15 is provided, and an opening at the end of the discharge outlet passage portion 31b. A discharge port 21 is formed. Note that the discharge ports 21 are not limited to the embodiments described above, and for example, a plurality of discharge ports 21 can of course be provided, and as shown in FIG. It may be provided so that cutting fluid can be applied from above.

In addition, in this embodiment, the cavity 11 provided in the distal end portion 10 is provided with a three-dimensional reinforcing structure 13 that supports the outer shell 12 forming the cavity 11 from the inside, and the three-dimensional reinforcing structure The space of the cavity 11 occupied by the cavity 13 is a communication space 14 in which no closed cell-shaped portion is provided.

According to this three-dimensional reinforcing structure 13, it is possible to increase the rigidity of the distal end portion 10 and improve its strength. Unmelted metal powder can be discharged from the cavity 11. The cavity 11 in which the three-dimensional reinforcing structure 13 of this embodiment is formed is a communication space 14, so that it has a structure that can also be used as a cutting fluid supply channel as a part of the coolant channel 31. ing.

Furthermore, this three-dimensional reinforcing structure 13 has a gyroid structure, as shown in the example shown in FIG. , can be with appropriate reinforcement structure

Note that the three-dimensional reinforcing structure 13 is not limited to this gyroid structure; for example, a lattice structure may be used as a reinforcing structure in which the cavity space is a communicating space 14 without a closed cell-shaped portion. can be adopted.

Furthermore, the chucked part (rear end part 30) that is attached to the cutting device in the cutting blade holder for boring in this embodiment is a narrow passage with a small diameter provided in the longitudinal direction along the axis, and is a coolant passage. Since it is substantially solid except for the axial flow path portion 31a that constitutes a part of the flow path 31, it has a structure with high compressive strength, and is configured to ensure the strength to be chucked. Note that it is also possible to carry out an optimization design that includes this rear end portion 30, and thereby, for example, it is possible to obtain a form that can appropriately save materials.

Although the present invention has been variously explained above using preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is about.

10 Tip side part 10a Tip part 11 Hollow part 12 Outer shell 13 Three-dimensional reinforcement structure 14 Communication space 15 Swelling part 20 Cutting blade mounting seat part 21 Discharge port 22 Female screw part for mounting 30 Rear end part 31 Coolant channel 31a Axial flow path section 31b Discharge port flow path section 40 Cutting blade

Claims (5)

A cutting blade holder for boring, which is provided in the shape of a rod and has a cutting blade mounting seat portion on the tip portion of which a cutting blade in the form of an exchangeable chip for boring processing is fixed,
The distal end portion including the distal end portion is formed to have a thinner outer shape than other portions including the rear end portion , and the cross-sectional shape cut perpendicularly to the axis of the rod-shaped shaft center is either line symmetrical or point symmetrical. It is set up asymmetrically without becoming
A hollow section provided inside the distal end portion including the distal end portion to increase the natural frequency has a cross-sectional shape cut perpendicular to the axis of the rod-shaped shaft center, which has either line symmetry or point symmetry. A cutting blade holder for boring that is characterized by being installed asymmetrically . 2. The hollow portion constitutes a part of a coolant flow path for flowing coolant to a discharge port provided at the tip end so as to cool the cutting blade. Cutting blade holder for boring. A three-dimensional reinforcement structure that supports the outer shell forming the cavity from the inside is provided in the cavity provided at the distal end portion, and a space in the cavity occupied by the three-dimensional reinforcement structure is closed. 3. The boring cutting blade holder according to claim 1, wherein the boring cutting blade holder has a communicating space in which no cell-shaped portion is provided. The boring cutting blade holder according to claim 3, wherein the three-dimensional reinforcing structure is a gyroid structure. A method for manufacturing a cutting blade holder for boring, which manufactures the cutting blade holder for boring according to any one of claims 1 to 4,The outer shell forming the cavity is designed using an optimization design method and formed by laser melting three-dimensional additive manufacturing.be able tocharacterized by Manufacturing method of cutting blade holder for boring.

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