RU2537642C1 - Cutting plate - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: cutting plate has a polygonal shape with two opposite end surfaces and peripheral surface located between them, meanwhile a middle plain M, intersecting the cutting plate, is located between end surfaces, viahole passing between end surfaces, cutting edge formed on the intersection of each end surface with the peripheral surface. Meanwhile the cutting edge has sequentially alternating and conjugate among themselves and separated by the top the sections of main and auxiliary cutting edges. The cutting edge tops in pairs one with reference to another are offset in plains of respectively opposite end surfaces on the plan from above on the cutting plate to the angles ά and β, the tangential bearing surfaces are located around the viahole on each opposite end surface and have faces with the shape of the second order surfaces. To minimise internal stresses in the cutting plate on each tangential bearing surface at least three faces are made which have the shape of the second order surfaces with tops located symmetrically with reference to the viahole axis and facing from its axis towards the periphery of the cutting plate, and depression directed along the tangent towards the viahole with the exit towards it, so on opposite tangential bearing surfaces the faces are located with 180 degrees mirror symmetry, and on the plan from above on the cutting plate the projection of axes of depressions of edges form a trigon, and the tops of faces of opposite tangential bearing surfaces are mutually shifted to an acute angle ά1 or β1, equal respectively to the angle ά or angle β of mutual shift of tops of cutting edges of opposite end surfaces of the cutting plate. The cutting tool, in particular face cutter, has the tool holder head with one or several sockets, meanwhile each socket has one bearing surface and side contact surfaces for the named cutting plate.

EFFECT: improvement of performance of cutting plate at processing of hard-processing materials at the expense of minimising of internal stresses.

8 cl, 10 dwg

Description

Technical field

The present invention relates to a double-sided indexable cutting insert used in the processing of materials by cutting, in particular for use in a cutting tool, such as a cutter.

State of the art

In the patent of the Russian Federation RU 2454392 a cutting insert of a polygonal shape is disclosed. It includes opposite end surfaces and a peripheral surface located between them, a middle plane located between the end surfaces, a through hole passing between the end surfaces, a cutting edge formed at the intersection of each end surface with a peripheral surface, the cutting edge is divided into identical cutting sections. Each section includes a main and auxiliary cutting edges. The tangential bearing surface is located between the cutting edge and the through hole. The main rear surface on the peripheral surface extends from each main cutting edge and forms an obtuse internal angle with a plane passing through the main cutting edge and parallel to the middle plane of the cutting insert. The minor rear surface forms an internal acute angle with a plane passing through the minor cutting edge and parallel to the middle plane of the cutting insert. Moreover, the main and auxiliary cutting edges of the insert in the side view are alternately convex and concave. In view of this design, the cutting insert is installed in the socket of the cutting tool body, the side contact surfaces of which are made in the form of a dovetail. In addition, the tangential bearing surface of the nest under the cutting insert is divided into three bearing sections.

An advantage of a cutting insert of the type disclosed in RF patent RU 2454302 is the possibility of its use for high-speed milling in combination with the inclined direction of feed movement and the improvement of chip evacuation during external milling.

The disadvantage of the cutting insert and cutting tool disclosed in the patent of the Russian Federation RU 2454302, is the lack of resistance when used for processing difficult materials. This is due to the fact that the cutting insert, mounted in the nest of the cutting tool with side contact surfaces in the form of a dovetail and with identical tangential surfaces that do not take into account the angular displacement of opposite end surfaces, both when fixing and when processing materials, is in a complex stress deformed condition, negatively affecting the resistance of its cutting edges. In this case, the separation of the end contact surface of the nest of the cutting tool also does not fully resolve the stresses arising in the cutting insert.

In the patent of the Russian Federation RU 2422253 a cutting insert and a milling tool are disclosed. The cutting insert has cutting edges located on opposite sides. In this case, the cutting edges protrude beyond the adjacent front cutting surfaces directed downward at a positive angle, and between them are one or more supporting planes and a central mounting hole. At least one face in the form of a truncated cone is located around the mounting hole, the face converging on the cone radially inward in the direction of the mounting screw.

An advantage of a cutting insert of the type disclosed in RF patent RU 2422253 is the possibility of increasing its efficiency due to improved contact of the end surfaces of the cutting plate with the end surfaces of the slot of the groove of the cutting tool. However, this arrangement of faces on the supporting surface of the cutting insert does not take into account the complex stress-strain state of the polygonal shape of the cutting insert and, thereby, reduces the efficiency of the known design.

In the patent of the Russian Federation RU 2455128 a cutting insert and a cutting tool are disclosed. The cutting insert has a polygonal prismatic shape with two opposite end surfaces. The cutting part of the cutting insert includes a main and auxiliary cutting edges, each of these cutting edges in a side view of the cutting insert has three sections - rectilinear, convex and concave.

The disadvantage of the cutting insert and cutting tool disclosed in the patent of the Russian Federation RU 2455128 is also the inability to take into account the complex stress-strain state of the polygonal shape of the cutting plate having a displacement of the same vertices of the cutting edges on opposite end surfaces of the cutting plate.

The present invention is the creation of an improved cutting insert for its use in the processing of difficult materials by reducing the internal stresses in the cutting insert arising both in the process of fixing, and in the processing of materials.

An object of the present invention is also to provide a cutting tool for securing such a cutting insert.

The problem is solved by means of a set of features given in the relevant claims. In particular, a polygonal-shaped cutting insert is proposed having tangential bearing surfaces with faces in the form of second-order surfaces with mirror 180-degree rotational symmetry, taking into account the mutual angular displacement of opposite end surfaces. As one of the preferred options, the cutting insert has a positive trailing angle on the main cutting edge. Also proposed is a cutting tool having a longitudinal axis of rotation and comprising a tool holder provided with several sockets, each socket having one supporting plane and side contact surfaces, and the proposed cutting insert is installed in each socket.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a cutting insert having:

a polygonal shape with two opposite end surfaces and a peripheral surface located between them, with the middle plane M intersecting the cutting insert located between the end surfaces, a through hole passing between the end surfaces;

the cutting edge formed at the intersection of each end surface with the peripheral surface, while the cutting edge contains successively alternating and conjugate and separated by apex sections of the main and auxiliary cutting edges, and the tops of the cutting edges are pairwise displaced relative to each other in the planes of respectively opposite end surfaces plan from the top to the insert at an angle ά and β;

tangential bearing surfaces are located around the through hole on each opposite end surface and have faces in the form of second-order surfaces.

In accordance with the present invention, at least three faces are made on each tangential supporting surface of the cutting insert in the form of second-order surfaces with vertices symmetrically relative to the axis of the through hole and directed from its axis to the periphery of the cutting insert, and a decrease tangential to the through hole with an exit to it, so that on opposite tangential surfaces the faces are arranged with 180-degree mirror symmetry, and on the plan from above on the cutting face y axes projection slides edges form a triangle, and the vertex faces opposing tangential abutment surfaces are mutually displaced by an acute angle ά1 or β1, respectively equal angle ά or β mutual displacement of the cutting edges of vertices opposing end surfaces of the cutting insert.

In accordance with one preferred embodiment, the faces are in the form of cone or paraboloid or hyperboloid or rotation ellipsoid or cylinder elements.

According to another preferred embodiment, the vertices (38) and (40) of the faces (62) are on one straight line perpendicular to the mid-plane M.

According to another preferred embodiment, the main rear surface on the peripheral surface extends from each main cutting edge and forms an acute inner angle γ with a plane P1 passing through the main cutting edge and parallel to the middle plane M.

According to another preferred embodiment, the minor back surface on the peripheral surface extends from each minor cutting edge and forms an obtuse angle θ with respect to the plane P2 passing through the minor cutting edge parallel to the middle plane M.

According to another preferred embodiment, the portion of the main cutting edge is straight or convex or concave, and the portion of the secondary cutting edge in a side view of the cutting insert is straight or convex-concave.

According to another preferred embodiment, the maximum convexity is on the main cutting edge.

In accordance with the present invention, there is provided a cutting tool, in particular a face mill, having:

the head of the tool holder with one or more sockets, each socket having one supporting surface and side contact surfaces for the cutting insert according to one of claims 1-8 of the claims installed in each socket.

In this case, the above-described cutting insert is installed in each socket and fixed with a fixing screw. Cutting inserts can be directly or indirectly installed in the sockets with the help of cassettes.

For a better understanding, but only as an example, the invention will be described with reference to the attached drawings, in which:

figure 1 shows a perspective view of a cutting insert in accordance with the present invention;

figure 2 shows a top view of the cutting insert shown in figure 1;

figure 3 shows a first variant of an enlarged view of B in figure 2;

figure 4 shows a second variant of an enlarged view of B in figure 2;

figure 5 shows a side view of the cutting insert in figure 1;

figure 6 partially shows a cross section of the cutting insert shown in figure 1, along the line I-I of figure 2;

figure 7 partially shows a cross section of the cutting insert shown in figure 1, along the line II-II of figure 2;

on Fig partially shows a cross section of the cutting insert shown in figure 1, along the line III-III of figure 2;

figure 9 shows a General view of the cutting tool using the cutting insert shown in figures 1-8;

figure 10 shows an enlarged socket for mounting the cutting insert in the housing of the cutting tool shown in Fig.9.

Detailed Description of Drawings

Consider FIGS. 1-10, showing a cutting insert 10 and a cutting tool 54 in which this insert is used.

The cutting insert 10 is indexable. It is preferably made by shaped or injection molding and sintering carbide powders.

The cutting insert 10 has a polygonal shape with two opposite end surfaces 12.

A peripheral surface 14 is located between the opposite end surfaces 12, the middle plane M crossing the cutting insert 10 is located between the end surfaces 12. A through hole 16 for securing the cutting insert 10 by means of a screw in the socket 58 of the cutting tool 54 extends between the end surfaces 12.

At the intersection of each end surface 12 with the peripheral surface 14, cutting edges are formed. The cutting edges are divided into three identical cutting sections 18. Each section of the cutting edge 18 contains successively alternating and conjugated to each other and separated by apex 20 and 22 sections of the main 24 and auxiliary 26 cutting edges.

The vertices of the cutting edges 28 and 30, 20 and 22 are pairwise displaced relative to one another in the planes of respectively opposite end surfaces 12 in the plan from above on the cutting insert 10, respectively, by the angles ά and β.

The tangential bearing surfaces 32 and 34 are located around the through hole 16 on each opposite end face 12 and have faces in the form of second-order surfaces.

According to the proposed design of the cutting insert around the through hole 16 of the cutting plate 10, at least three faces 36 and 38 are made on each tangential supporting surface 32 and 34 in the form of second-order surfaces with vertices 40 and 42 located symmetrically with respect to the axis 44 of the through hole 16 and directed from its axis 44 to the periphery of the cutting insert 10.

The lowering of the faces 36 and 38 is directed tangentially to the through hole 16 with access to it, so that on the opposite tangential bearing surfaces 32 and 34, the faces 36 and 38 are arranged with 180-degree mirror symmetry, and on the plan from above on the cutting insert 10 are the projections of the axes of the lowering faces form a triangle.

In this case, the vertices 40 and 42 of the faces 36 and 38 located on opposite tangential bearing surfaces 32 and 34 are also mutually displaced in the plan from above onto the cutting insert 10 by an acute angle ά1 or β1 equal to, respectively, the angle ά or β of the mutual mixing of the vertices 28 and 30 or tops 20 and 22 of the cutting edges of the opposite end surfaces 12 of the cutting insert 10.

The direction of the faces 36 and 38 can be reversed, shown as an example in FIGS. 1 and 2, and the angle of displacement of their vertices 40 and 42 can be chosen equal to the angle ά1 or β1.

As a preferred embodiment, the surfaces of faces 36 and 38 may be in the form of cone, or paraboloid, or hyperboloid, or rotation ellipsoid, or cylinder elements. The choice of the specific shape of these surfaces is determined by a conventional engineering solution when calculating the stress-strain state of the cutting insert 10, taking into account the unhindered chip flow.

In the above design features of the tangential bearing surfaces 32 and 34 of the cutting insert 10, the mutual angular displacement (angles ά and β) of the opposing end surfaces 12 is taken into account so that virtually every tangential bearing surface 32 and 34 redistributes as the working load from the cutting edge 18 of the opposite end face 12, and the load from fixing the plate with a screw in the slot of the cutter, taking into account the reduction of internal stresses in the plate 10.

In order to ensure the efficiency of the cutting insert when processing materials with different physical and mechanical characteristics, the location of the vertices 40 and 42 of the faces 36 and 38 on the plan from above on the plate 10 can coincide and be on the same straight line, perpendicular to the middle plane M of the plate 10.

In accordance with one most preferred embodiment, the main rear surface 46 on the peripheral surface 14 extends from each main cutting edge 24 and forms an angle γ with a plane P1 passing through the main cutting edge 24 and parallel to the middle plane M of the plate 10. This ensures, taking into account the reduction in internal stresses wider use of the insert 10.

The minor rear surface 48 extends from each minor cutting edge 26 on the peripheral surface 14 from each minor cutting edge 26 and forms an obtuse internal angle θ with respect to the plane P2 passing through the minor cutting edge 26 and parallel to the median plane M of the plate 10.

The cutting insert shown in FIGS. 1-7 may have a cutting edge 18 with straight sections of the main 24 and auxiliary 26 cutting edges.

To ensure wider use of the cutting insert 10, the main cutting edge 24 of the cutting insert 10 can also be made convex or concave, and the portion of the auxiliary 26 cutting edge in a side view of the cutting insert 10 is made straight or convex-concave. In this case, the convexity of the main cutting edge 24 can be conjugated with either a concave one embodiment or convex parts of the auxiliary cutting edge 26. In another preferred embodiment, the maximum convexity 52 can be located on the convex main cutting edge 24 .

The cutting tool 54 shown in Fig.9, according to one of the preferred options has a longitudinal axis of rotation A and contains:

a tool holder 56 provided with several sockets 58, each socket 58 having one abutment surface 60 and two lateral contact surfaces 62. A threaded hole 64 passes through the abutment surface 60. A cutting insert 10 is installed in each socket 58 and fastened with a screw 66. Cutting inserts 10 can also be installed in the tool holder sockets using cassettes in which the sockets 58 are made.

The above arrangement and shape of the faces 36 and 38 of the cutting insert 10 located on opposite tangential bearing surfaces 32 and 34, as well as the shape and relative position of the cutting edges 24 and 26, can improve the stress-strain state of the cutting insert 10, which occurs when it is fixed in nest 58 of the cutting tool 54, and in the processing of difficult to process material, thereby increasing its durability and efficiency.

Although the present invention has been described with a certain degree of detail, it should be understood that various changes and modifications can be made without departing from the essence and scope of the invention set forth in the following claims

Claims (8)

1. The cutting insert (10) having a polygonal shape with two opposite end surfaces (12) and a peripheral surface (14) located between them, while the middle plane (M) intersecting the cutting insert is located between the end surfaces, a through hole ( 16), passing between the end surfaces (12), the cutting edge (18), formed at the intersection of each end surface (12) with the peripheral surface (14), while the cutting edge (18) contains alternating and interconnected and separated portions of the main (24) and auxiliary (26) cutting edges identified by the apex, the vertices (20, 22) and (28, 30) of the cutting edge being pairwise displaced relative to each other in the planes of respectively opposite end surfaces (12) on the plan from above on the cutting insert (10) at angles ά and β, tangential bearing surfaces (32) and (34) are located around the through hole (16) on each opposite end surface (12) and have faces in the form of second-order surfaces, characterized in that on each tangential bearing surface (32, 34) dir At least three faces (36) and (38) in the form of second-order surfaces with vertices (40) and (42) symmetrically relative to the axis of the through hole and directed from its axis (44) to the periphery of the cutting plate (10) are made plate (10), and lowering, tangential to the through hole (16) with access to it, while on the opposite tangential bearing surfaces (32) and (34), the faces (36), (38) are located with a 180-degree mirror symmetry, and on the plan from above on the cutting insert (10), the projections of the axes of lowering the faces (36), (38) a triangle forms, and the vertices (40), (42) of the faces of the opposing tangential supporting surfaces are mutually offset by an acute angle ά1 or β1, respectively equal to the angle ά or the angle β of the mutual displacement of the vertices (28, 30) and (20, 22) of the cutting edges of the opposite end surfaces (12) of the insert (10). 2. The cutting insert according to claim 1, characterized in that the faces (36, 38) are made in the form of elements of a cone or paraboloid, or a hyperboloid, or an ellipsoid of revolution, or a cylinder. 3. The cutting insert according to claim 1, characterized in that the vertices (40, 42) of the faces (36, 38) are on one straight line, perpendicular to the middle plane M. 4. The cutting insert according to claim 1, characterized in that the main rear surface (46) on the peripheral surface (14) extends from each main cutting edge (24) and forms an internal acute angle γ with a plane P1 passing through the main cutting edge ( 24) and parallel to the middle plane (M). 5. The cutting insert according to claim 1, characterized in that the auxiliary rear surface (48) extends on the peripheral surface (14) from each auxiliary cutting edge (26) and forms an internal obtuse angle θ with respect to the plane P2 passing through the auxiliary cutting edge ( 26) and parallel to the middle plane M. 6. The cutting insert according to claim 1, characterized in that the section (24) of the main cutting edge is made rectilinear, convex or concave, and the section of the auxiliary (26) cutting edge in the side view of the cutting plate is made straight or convex-concave. 7. The cutting insert according to claim 6, characterized in that the maximum convexity (52) is located on the main cutting edge. 8. A cutting tool 54, in particular a face mill, having a tool holder head 56 with one or more sockets (58), characterized in that each socket (58) has one supporting surface (60) and side contact surfaces (62) for the cutting insert (10) according to one of paragraphs 1-7, installed in each slot.

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