RU2759490C1 - Cutting plate for a milling cutter and milling cutter - Google Patents

Abstract

FIELD: processing of materials.

SUBSTANCE: invention relates to processing of materials by cutting and can be used for treatment of surfaces using assembled milling cutters with mechanical securing of indexable throwaway cutting plates. The cutting plate is restricted by two identical end surfaces and a peripheral surface located between said surfaces. Parallel lower support surfaces are located on the end surfaces, and side support surfaces are located on the peripheral surface. Grooves with additional side support surfaces are located on each end surface, and a section of the lower support surface is located at the bottom of each groove. Side support walls and a lower support wall, the sections whereof are located on the protrusions of the socket, are made in the socket of the body of the milling cutter. On the protrusion of the socket under the working top of the cutting plate, additional support walls are made for interaction with the additional support surfaces of the corresponding groove of the cutting plate.

EFFECT: reliability of securing the cutting plate in the socket of the body of the milling cutter is increased, productivity of processing is heightened.

3 cl, 8 dwg

Description

The invention relates to the field of processing materials by cutting using prefabricated cutters with mechanical fastening of multifaceted non-regrowth cutting inserts.

Known cutting insert for a cutter, limited by two opposite identical end surfaces and a peripheral surface located between them, the cutting insert has an axis of symmetry coinciding with the axis of the through hole passing between the end surfaces, and the cutting insert has 3-fold rotational symmetry when rotating around the mentioned axis of symmetry, in a top view along the axis of symmetry, each end surface has the shape of a hexagon with three acute angles and three obtuse angles located alternately along the periphery, and the bisectors of opposite acute and obtuse angles lie on one straight line passing through the axis of symmetry of the cutting insert, when three cutting edges are formed at the intersection of each of the end surfaces with the peripheral surface, each cutting edge includes two straight sections converging to the top of an acute angle and connected by a radius section, parallel lower support along the surface, and on the peripheral surface - lateral support surfaces, converging in pairs to the tops of obtuse angles (see. RF patent RU 2719239, В23С 5/06, 2020), / 1 /.

Also known is a cutter (see / 1 /) containing a housing having an axis of rotation, on the periphery of which there are sockets for installation and fastening by means of screws with a tapered head of the mentioned cutting inserts. In this case, each of the slots is limited by the lower support wall for interaction with the lower support surface of the cutting insert and the side support walls for interaction with the side support surfaces of the cutting insert. In addition, each seat has a threaded hole for interacting with a tapered screw when securing the cutting insert, and the axis of the threaded hole intersects the bisector of the obtuse angle between the side support walls.

Due to the sharp angle at the working tip of the cutting insert, the known cutters can have a entering angle of 90 ° and are designed to make closed grooves and pockets in the workpiece. Such processing is carried out with an oblique feed, in which the cutting edges adjacent to the working tip of the cutting insert, in one revolution of the cutter, alternately become the main and auxiliary cutting edges, i.e. cutting forces act on the cutting insert in opposite directions, which reduces the reliability of fastening the cutting insert in the socket of the cutter body, limits the feed per tooth and, accordingly, the processing efficiency.

Thus, the technical problem to be solved consists in increasing the productivity of machining with an inclined feed by increasing the feed per tooth by increasing the reliability of fixing the cutting insert in the socket of the cutter body.

The specified technical problem in relation to the cutting insert is solved by the fact that the cutting insert for a cutter, bounded by two opposite identical end surfaces and a peripheral surface located between them, has an axis of symmetry coinciding with the axis of the through hole passing between the end surfaces, and the cutting insert has 3-fold rotational symmetry when rotating around the mentioned axis of symmetry, in a top view along the axis of symmetry, each end surface has the shape of a hexagon with three acute angles and three obtuse angles located alternately along the periphery, and the bisectors of opposite acute and obtuse angles lie on one straight line passing through the axis of symmetry of the cutting insert, while three cutting edges are formed at the intersection of each of the end surfaces with the peripheral surface, each cutting edge includes two straight sections converging to the top of an acute angle and connected by a radius section, on the end surfaces are parallel lower support surfaces, and on the peripheral surface there are side support surfaces, converging in pairs to the tops of obtuse corners, according to the invention, on each end surface there are three grooves having symmetry axes coinciding with the mentioned straight lines passing through the axis of symmetry of the cutting insert and coinciding with the bisectors of opposite acute and obtuse corners, each groove is bounded by the bottom, on which a portion of the lower support surface is located, and additional side support surfaces located on the sides of the axis of symmetry of the groove and diverging towards the axis of symmetry of the cutting insert.

The specified technical problem is also solved by the fact that, on the peripheral surface there are two sections, each of which intersects with one of the end surfaces, and these sections are located symmetrically at an acute angle less than 90 ° relative to the plane of symmetry perpendicular to the axis of symmetry of the cutting insert and located along the middle between the lower bearing surfaces of the end surfaces. The implementation of these sections on the peripheral surface allows, during the production of the cutting insert, to facilitate the implementation of the exact relative position of the side support surfaces and additional support surfaces, as well as simultaneously ensure the exact relative position of the side support surfaces and the tops of the cutting insert for each end surface.

With regard to the cutter, the specified technical problem is solved by the fact that the cutter comprises a housing having an axis of rotation, at the periphery of which there are seats for mounting and fastening said cutting inserts by means of screws with a tapered head. Each of the slots is delimited by a lower abutment wall for interaction with the lower abutment surface of the cutting insert and side abutment walls for interaction with the lateral abutment surfaces of the cutting insert. In addition, each seat has a threaded hole for interacting with the tapered screw when securing the cutting insert, the axis of the threaded hole intersecting the bisector of the obtuse angle between the side abutment walls. In this case, the lower support wall of each nest is made in the form of three sections located on the nest projections, made with the possibility of placement in the corresponding grooves of the cutting insert when it is installed in the nest, moreover, additional side support walls are made on the nest ledge located under the working tip of the cutting insert for interaction when fixing the cutting insert with additional side support surfaces in the corresponding slot of the cutting insert.

The proposed cutting insert and milling cutter are shown in FIG. 1-8, on which:

in fig. 1 shows a front view of a cutting insert;

in fig. 2 shows a top view of the cutting insert;

in fig. 3 shows a section a-a in fig. 2;

in fig. 4 shows a section b-b in fig. 2;

in fig. 5 shows a top view of the socket of the cutter body with the cutting insert fixed therein;

in fig. 6 shows a top view of the cutter body socket without the insert and the fixing screw;

in fig. 7 shows section b-b in fig. 5;

in fig. 8 shows a section D-G in Fig. 5.

The cutting insert (1) for the cutter is limited by two opposite identical end surfaces (2, 3) and a peripheral surface (4) located between them.

The cutting insert (1) has an axis of symmetry (5) coinciding with the axis of the through hole (6) passing between the end surfaces (2, 3), and the cutting insert has a 3-fold rotational symmetry when rotating around the mentioned axis of symmetry. The through hole (6) has a tapered section on the side of each end surface for interaction with the tapered head of the fastening screw when fixing the cutting insert.

In the top view along the axis of symmetry (5), each end surface has the shape of a hexagon with three acute (7) corners and three obtuse (8) corners located alternately along the periphery, and the bisectors of opposite acute and obtuse angles lie on one straight line passing through the axis symmetry (5) of the cutting insert.

In this case, three cutting edges are formed at the intersection of each of the end surfaces with the peripheral surface, each cutting edge includes two straight sections (9) converging to the top of an acute angle and connected by a radius section (10).

On the end surfaces (2, 3) there are parallel lower support surfaces (11), and on the peripheral surface there are side support surfaces (12), converging in pairs to the tops of obtuse corners (8).

On each end surface (2, 3), three grooves (13) are made, having axes of symmetry coinciding with the mentioned straight lines passing through the axis of symmetry of the cutting insert and coinciding with the bisectors of opposite acute and obtuse angles. Each groove is limited by a bottom (14), on which a portion of the lower support surface (11) is located, and additional side support surfaces (15) located on the sides of the axis of symmetry of the groove and diverging towards the axis of symmetry of the cutting insert.

The cutter (16) contains a housing (18) with an axis of rotation (17), on the periphery of which there are sockets for mounting and fastening by means of screws with a tapered head of cutting inserts (1). The body (17) has a shank (not shown) for attaching the cutter to the spindle of the machine.

Each of the slots is limited by a lower support wall (19) for interaction with the lower support surface (11) of the cutting insert and side support walls (20) for interaction with the side support surfaces (12) of the cutting insert.

Each seat has a threaded hole (21) for interaction with a screw (22) with a tapered head when fixing the cutting insert, and the axis of the threaded hole intersects the bisector of the obtuse angle between the side support walls and is offset from the axis of symmetry towards the side support walls (20).

In this case, the lower support wall (19) of each socket is made in the form of three sections (23) located on the projections (24) of the socket, made with the possibility of placement in the corresponding grooves (13) of the cutting insert when it is installed in the socket, and on the projection of the socket, located under the working tip of the cutting insert, additional side support walls (25) are made for interaction when fixing the cutting insert with additional side support surfaces (15) in the corresponding groove of the cutting insert.

During assembly, the cutting insert is installed in the socket so that the projections (24) of the socket enter the grooves (13) of the cutting insert until the portions of the lower support surface (11) contact with the portions (23) of the lower support wall (19). Then, when screwing in the fastening screw (22), its conical head interacts with the corresponding conical section of the hole (6) and displaces the cutting insert until the lateral support surfaces (12) come into contact with the side support walls (20) and the additional support surfaces (15) of the groove (13 ) of the cutting insert (1) under the working tip with additional support walls (25) of the projection (24) of the socket under the working tip of the cutting insert, which makes it possible to increase the reliability of fixing the cutting insert under variable loads from cutting forces during oblique milling.

Claims (11)

1. A cutting insert for a cutter, bounded by two opposite identical end surfaces and a peripheral surface located between them, while the cutting insert has an axis of symmetry coinciding with the axis of the through hole passing between the end surfaces, and the cutting insert has 3-fold rotational symmetry when rotating around said axis of symmetry, in a top view along the axis of symmetry, each end surface has the shape of a hexagon with three acute angles and three obtuse angles located alternately along the periphery, and the bisectors of opposite acute and obtuse angles lie on one straight line passing through the axis of symmetry of the cutting insert, wherein three cutting edges are formed at the intersection of each of the end surfaces with the peripheral surface, each cutting edge includes two straight sections converging to the top of an acute angle and connected by a radius section, on the end surfaces there are parallel lower support surfaces, and on the peripheral surface there are side support surfaces converging in pairs to the tops of obtuse angles, characterized in that on each end surface there are three grooves with axes of symmetry coinciding with the mentioned straight lines passing through the axis of symmetry of the cutting insert and coinciding with the bisectors of opposite acute and obtuse angles, while each groove is bounded by the bottom, on which the section of the lower support surface, and additional side support surfaces located on the sides of the axis of symmetry of the groove and diverging towards the axis of symmetry of the cutting insert. 2. The cutting insert according to claim 1, characterized in that two sections are made on the peripheral surface, each of which intersects with one of the end surfaces, and these sections are located symmetrically at an acute angle less than 90 ° relative to the plane of symmetry perpendicular to the axis of symmetry of the cutting insert and located in the middle between the lower support surfaces of the end surfaces. 3. A cutter containing a housing having an axis of rotation, on the periphery of which there are sockets for installation and fastening by means of screws with a tapered head of cutting inserts according to claim 1 or 2, while each of the slots is bounded by a lower abutment wall for interaction with the lower abutment surface of the cutting insert and side abutment walls for interaction with the lateral abutment surfaces of the cutting insert, each seat has a threaded hole for interaction with a tapered screw when securing the cutting insert, the axis of the threaded hole intersecting the bisector of the obtuse angle between the side support walls, in this case, the lower support wall of each socket is made in the form of three sections located on the projections of the socket, made with the possibility of placement in the corresponding grooves of the cutting insert when it is installed in the socket, moreover, on the projection of the socket located under the working tip of the cutting insert, additional side support walls are made for interaction when fixing the cutting insert with additional side support surfaces in the corresponding slot of the cutting insert.

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