CN115106584A - Cutting insert and cutting tool - Google Patents

Abstract

The invention provides a cutting insert and a cutting tool. The cutting insert has a first surface in the shape of a rotationally symmetric polygon, a second surface located on the opposite side of the first surface, an outer peripheral surface located between the first surface and the second surface, and a central axis passing through the centers of the first surface and the second surface; the first surface comprises a first edge, a first corner, a second corner, a front corner surface arranged along the first edge, a chip removal groove surface arranged along the front corner surface, and a constraint surface arranged along the front corner surface and the chip removal groove surface; the first edge comprises a first edge part, a second edge part and a transition edge part; the front corner face comprises a first front corner face arranged along the first edge part, a second front corner face arranged along the second edge part and a third front corner face arranged along the transition edge part; the chip removal groove face is far away from the second surface along with being far away from the front corner face, and the chip removal groove face is connected with the first front corner face and the third front corner face and is far away from the second front corner face. The invention can obtain good chip treatment effect and is beneficial to the reduction of the size of the blade.

Description

Cutting inserts and cutting tools

technical field

The invention relates to the field of cutting tools, in particular to a cutting insert and a cutting tool.

Background technique

Chinese invention patent application CN105478873A discloses a cutting insert with an asymmetrical cutting edge. Such an insert has two opposing surfaces and four circumferential side surfaces, the two opposing surfaces and the four circumferential side surfaces respectively form four cutting edges, each cutting edge being divided into a first part, a second part and a transition radius. Among them, the length of the first part is L1 and the length of the second part is L2, so that L1>L2, and the transition radius is not located at the midpoint of the cutting edge. This technical solution solves the problem of increasing the height of the shoulder available for cutting by the cutting insert.

However, in this solution, due to the need to ensure the cutting performance of the insert, the insert generally has a large rake angle, and also requires a large enough restraint surface for restraint and a rake surface for controlling chip removal. The space between the surface and the restraint surface is small, and the chip removal space is small, so the blade is generally larger, the raw material is used more, and the cost is high. In addition, if the size of the insert is reduced by increasing the distance between the cutting edge and the restraining surface, problems such as reduced insert strength and difficulty in forming are likely to occur.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a cutting insert, which can obtain a good chip treatment effect and facilitate the reduction of the size of the insert.

Another object of the present invention is to provide a cutting tool having the above-mentioned cutting insert.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

According to one aspect of the present invention, the present invention provides a cutting insert having:

a first surface, which is a rotationally symmetric polygon;

a second surface on the opposite side of the first surface;

an outer peripheral surface located between the first surface and the second surface; and

a central axis passing through the center of the first surface and the center of the second surface;

The first surface includes:

first edge;

a first corner, connecting the first edge;

The second corner is connected to the first edge;

a rake surface, disposed along the first edge, and approaching the second surface as it moves away from the first edge;

a chip flute surface disposed along the rake face and away from the second surface as it moves away from the rake face; and

a restraining surface, disposed along the rake surface and the chip flute surface, closer to the second surface than the first edge, and perpendicular to the central axis;

The first edge includes:

a first blade extending from the first corner to the second corner and approaching the second surface as it approaches the second corner;

a second blade portion extending linearly from the second corner to the first corner, and approaching the second surface as it approaches the first corner; and

a transition edge, connecting the first edge and the second edge, and approaching the second surface as it approaches the first corner;

When looking directly at the outer peripheral surface, the inclination angle of the transition blade portion is greater than the inclination angle of the second blade portion;

The front corner surface includes:

a first rake face, arranged along the first blade;

a second rake face disposed along the second edge portion; and

a third rake face, arranged along the transition blade;

The chip flute surface connects the first rake surface and the third rake surface, and is away from the second rake surface.

In some embodiments, the flute surface is closer to the second surface than the restraint surface.

In some embodiments, the flute face has a first end closest to the first corner and a second end closest to the second corner, the first end being connected to the first rake face The second end is connected to the third rake surface; the chip flute surface has the most concave part closest to the second surface relative to the restraining surface, and the most concave part is located at the between the first end and the second end.

In some embodiments, in a direction extending along the first edge, the most concave portion is closer to the first corner than the junction of the first edge portion and the transition edge portion .

In some embodiments, viewed from the direction facing the restraint surface, the projected length of the distance from the first end to the second end along the extending direction of the first edge is L1, and the first end The projected length of the distance to the most concave point along the extending direction of the first edge is L2, and L2/L1=1/2˜2/3.

In some embodiments, the included angle between the chip flute surface and the plane where the restraining surface is located is α, and there is a first position from the first end to the most concave part and a first position closer to the most concave part. In the second position of the recess, the included angle α at the first position is smaller than the included angle α at the second position.

In some embodiments, at different positions between the first end and the second end, the variation range of the included angle α is: 0°<α<40°.

In some embodiments, the rake face further includes an extension face connected between the first rake face and the chip flute face; in the direction toward the central axis, the extension face moving away from the first rake face and approaching the second surface.

In some embodiments, the included angle between the extension surface and the plane where the restraint surface is located is β, and at different positions of the extension surface along the extension direction of the first edge, the included angle β changes The range is: 0°<β<35°.

In some embodiments, the projected length of the chip flute surface along the extending direction of the first edge is 1/7˜1/3 of the side length of the first surface.

In some embodiments, the length of the first blade portion is greater than the length of the second blade portion.

According to another aspect of the present invention, the present invention also provides a cutting tool, comprising a tool holder and the above-mentioned cutting insert mounted on the tool holder.

It can be seen from the above technical solutions that the present invention has at least the following advantages and positive effects: in the cutting insert of the present invention, each edge portion on the first edge adopts an inclined extension setting, which can increase the extension length of the edge portion and ensure the machining of the insert. performance. Compared with the cutting edge on the first surface, the restraining surface is concave to the second surface, so there can be a larger space for chip removal between the restraining surface and the cutting edge, and at the same time, the first rake surface can be guaranteed to have sufficient width and The angle is convenient to ensure the cutting performance of the insert and guide the discharge of chips. Through the setting of the chip flute surface, the chips generated along the first rake face can be blocked, so that the chips are curled and discharged out of the insert along the chip flute face, so as to avoid the chips from scraping on the same first edge and not participating in cutting. The second blade section plays a very good role in protecting the cutting edge. Through the guide of the chips facing the chip removal groove, the chips are more easily discharged and the chip removal space of the cutting insert is saved. Under the condition of ensuring the same cutting edge shape, the overall shape of the cutting insert can be reduced, which is beneficial to the reduction of the overall size of the cutting insert. , reduce the use of blade raw materials and reduce costs.

Description of drawings

FIG. 1 is a schematic diagram of an embodiment of a cutting tool of the present invention.

Figure 2 is a schematic view of a perspective view of an embodiment of a cutting insert of the present invention.

FIG. 3 is a schematic view of the cutting insert of FIG. 2 viewed from the outer peripheral surface.

FIG. 4 is a plan view of FIG. 3 .

FIG. 5 is a partial enlarged view of part A in FIG. 4 .

FIG. 6 is a cross-sectional view at G-G in FIG. 5 .

FIG. 7 is a cross-sectional view at H-H in FIG. 5 .

FIG. 8 is a cross-sectional view at J-J in FIG. 5 .

Reference numerals are explained as follows: 1. Cutting insert; 2. Tool handle; 3. Fastener;

11, the first surface; 111, the first edge; 1111, the first blade; P, the junction; 1112, the second blade; 1113, the transition blade; 112, the first corner; 1121, the first corner Blade; 113, second corner; 1131, second corner blade; 114, rake face; 1141, first rake face; 1142, second rake face; 1143, third rake face; 1145, extension surface; 115, flute surface; 1151, first end; 1152, second end; 1153, most concave; 116, restraint surface; 118, groove;

12. The second surface;

13. Peripheral surface;

14. Center hole; CL, center shaft.

Detailed ways

Exemplary embodiments embodying the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various changes in different embodiments without departing from the scope of the present invention, and the descriptions and drawings therein are essentially used for illustration rather than limitation this invention.

Referring to FIG. 1 , an embodiment of the present invention provides a cutting tool. The cutting tool includes a handle 2 and a cutting insert 1 mounted on the handle 2 through a fastener 3 .

In this embodiment, the tool holder 2 is a face milling cutter disc structure. A plurality of cutting inserts 1 are attached along the circumferential direction of the shank 2 , and the workpiece is machined with the rotation of the shank 2 .

The specific structure of the tool holder 2 and the matching structure of the cutting insert 1 and the tool holder 2 can be flexibly set according to the actual situation, which is not limited here.

The specific structure of the cutting insert 1 will be described in detail below with reference to the accompanying drawings.

Referring to FIGS. 2 to 8 , the cutting insert 1 of this embodiment is an indexable insert. In particular, in this embodiment, the cutting insert 1 can also be used on both sides.

The cutting insert 1 has a first surface 11 , a second surface 12 located on the opposite side of the first surface 11 , and an outer peripheral surface 13 located between the first surface 11 and the second surface 12 . The cutting insert 1 also has a central hole 14 penetrating the first surface 11 and the second surface 12, and the central hole 14 is used for the fastener 3 to pass through, so that the cutting insert 1 is mounted on the shank 2 (as shown in FIG. 1 shown). The first surface 11 and the second surface 12 are both rotationally symmetrical polygons, and the first surface 11 and the second surface 12 are center-symmetrical to each other, and the center of the first surface 11 and the center of the second surface 12 are both located in the central hole 14 on the central axis CL. The cutting insert 1 as a whole is rotationally symmetrical about the central axis CL.

Referring to FIG. 2 , the first surface 11 includes a first edge 111 , a first corner 112 connected to one end of the first edge 111 , a second corner 113 connected to the other end of the first edge 111 , and arranged along the first edge 111 The rake face 114 , the chip flute surface 115 arranged along the rake face 114 , and the restraint surface 116 arranged along the rake face 114 and the chip flute face 115 .

Wherein, the first edge 111 , the first corner 112 and the second corner 113 are located on the outer edge of the first surface 11 for forming the cutting edge of the cutting insert 1 . The restraining surface 116 is used to form a restraint with the shank 2 to maintain the tightening of the cutting insert 1 on the shank 2 . The restraining surface 116 is disposed around the central hole 14 and is perpendicular to the central axis CL. The restraining surface 116 is closer to the second surface 12 than the first edge 111 . The cutting edge is concave towards the second surface 12 so that there may be more chip evacuation space between the restraining surface 116 and the cutting edge. The rake surface 114 and the flute surface 115 are connected between the first edge 111 and the restraint surface 116 .

Referring to FIG. 4 , the projection of the first surface 11 is substantially in the shape of a square, and four corners of the square are transitioned by arcs. Here, the side length of the square is defined as L0, and the side length L0 can be measured by projection. The outer edge of the first surface 11 has four first edges 111 , and each of the first edges 111 extends along the side length direction of the square. The distance between the two opposite first edges 111 is the side length L0 of the first surface 11 .

The first corner 112 and the second corner 113 are respectively connected between two adjacent first edges 111 . The first corner 112 and the second corner 113 are actually the same structure, but are artificially distinguished in names for convenience of description. Specifically, referring to the view direction of FIG. 4 , for a specific first edge In terms of 111 , the first corner 112 is located in the clockwise direction of the first edge 111 , and the second corner 113 is located in the counterclockwise direction of the first edge 111 . In this embodiment, the first corner 112 and the second corner 113 are both arc-shaped, and two ends of the arc are respectively connected to two adjacent first edges 111 . In other embodiments, the first corner 112 and the second corner 113 may also be straight lines, and are respectively connected with two adjacent first edges 111 obliquely. In this case, the projection of the first surface 11 is a square. Bevel transitions are formed at the four corners.

The first corner 112 is provided with a first corner blade 1121 , and the second corner 113 is provided with a second corner blade 1131 . From the first corner 112 or the second corner 113 to the direction of the central axis CL, the constraining surface 116 may be connected by a plane or curved surface in the form of a step, and these planes or curved surfaces define the first corner edge portion 1121 or the second corner edge portion 1121 or the second The rake of the corner blade 1131.

2 and 3 , the first edge 111 includes a first edge portion 1111 , a second edge portion 1112 and a transition edge portion 1113 connected between the first edge portion 1111 and the second edge portion 1112 .

The first blade portion 1111 extends from the first corner 112 to the second corner 113 , and approaches the second surface 12 as it approaches the second corner 113 . The first blade portion 1111 may extend in a straight line as a whole, may extend in a multi-segment straight line, or extend in a shape combining straight lines and curves, and the specific extension shape may be designed according to actual needs.

One end of the first edge portion 1111 is connected to the first corner 112 with a smooth transition, and the other end is connected to the transition edge portion 1113 with a smooth transition, wherein the junction of the first edge portion 1111 and the transition edge portion 1113 is marked as P. In this embodiment, the first blade portion 1111 has a larger extension length, and the junction P is more inclined to the second corner 113 , that is, the distance between the junction P and the second corner 113 is smaller than that between the junction P and the second corner 113 . A distance between corners 112.

The second blade portion 1112 extends from the second corner 113 to the first corner 112 , and approaches the second surface 12 as it approaches the first corner 112 . The second blade portion 1112 extends in a straight line, and two ends of the second blade portion 1112 are connected to the second corner 113 and the transition blade portion 1113 in a smooth transition, respectively. The length of the second blade portion 1112 is smaller than the length of the first blade portion 1111 . As shown in FIG. 3 , the included angle between the second blade portion 1112 and a plane S perpendicular to the central axis CL is defined as the inclination angle θ2 of the second blade portion 1112 .

The transition edge portion 1113 extends linearly between the first edge portion 1111 and the second edge portion 1112 , and approaches the second surface 12 as it approaches the first corner 112 . As shown in FIG. 3 , the included angle between the transition blade portion 1113 and a plane S perpendicular to the central axis CL is defined as the inclination angle θ3 of the transition blade portion 1113 . The inclination angle θ3 of the transition blade portion 1113 is larger than the inclination angle θ2 of the second blade portion 1112 .

When the cutting insert 1 is in use, the first edge 1111 on one of the first edges 111 and the second edge 1112 on the adjacent first edge 111, the transition edge 1113, and the connecting The first corner edge portion 1121 or the second corner edge portion 1131 between the two first edges 111 is combined to perform right-angle surface machining on the workpiece. The first blade portion 1111 is generally used as a main cutting edge to process the side end surface of the workpiece, and the combination of the second blade portion 1112 and the transition blade portion 1113 is used as a secondary cutting edge or wiper edge to process the bottom surface of the workpiece. In this embodiment, since the first blade portion 1111 has a relatively large extension length, the processing efficiency can be ensured. The second edge portion 1112 and the transition edge portion 1113 are combined to form a two-stage structure and are designed with different inclination angles. When the size of the blade is limited, the secondary cutting edge can also have a suitable length to ensure its processing performance.

Referring to FIG. 2 , the rake surface 114 extends from the first edge 111 toward the center hole 14 by a certain width, and approaches the second surface 12 as it moves away from the first edge 111 . The inclined extending arrangement of the rake face 114 ensures the width and angle of the rake face 114 , so as to ensure the strength and sharpness of the cutting edge and chip discharge performance, thereby ensuring the cutting performance of the cutting insert 1 .

Specifically, referring to FIG. 4 , the rake face 114 includes a first rake face 1141 disposed along the first edge portion 1111 , a second rake face 1142 disposed along the second edge portion 1112 , and a first rake face 1142 disposed along the transition edge portion 1113 Three front corners 1143. The first rake surface 1141 defines the rake angle of the first blade 1111 , the second rake surface 1142 defines the rake of the second blade 1112 , and the third rake surface 1143 defines the rake of the transition blade 1113 . The specific inclination angles and extension shapes of the first rake surface 1141 , the second rake surface 1142 and the third rake surface 1143 can be designed according to actual requirements.

Referring to FIGS. 2 and 4 , the chip flute surface 115 extends from the rake surface 114 toward the center hole 14 , and moves away from the second surface 12 as it moves away from the rake surface 114 . The chip flute surface 115 connects the first rake surface 1141 and the third rake surface 1143 and is far away from the second rake surface 1142 . In the direction extending along the first edge 111 , the chip flute surface 115 is in contact with a part of the first rake surface 1141 , is in contact with a part of the third rake surface 1143 , but is not in contact with the second rake surface 1142 connected.

The chip flute surface 115 is located between the first edge 111 and the restraining surface 116 , so as to ensure the angle and width of the rake surface 114 so as to ensure the cutting performance of the cutting insert 1 . At the same time, when the chips generated by the first cutting edge 1111 are generated along the first rake face 1141 and hit the chip flute surface 115 , due to the inclined setting of the chip flute surface 115 , the chips will be removed by the chip flute surface 115 . The blocking is curled, and then it is discharged along the chip flute surface 115 in a direction away from the first surface 11, that is, it is discharged to the outside of the cutting insert 1, so that the chips can be prevented from scraping on the same first edge 111. The blade portion 1112 plays a very good role in protecting the cutting edge. The chips are guided by the chip flute surface 115, so that the chips can be discharged more easily, and the chip removal space of the cutting insert 1 can be saved. Under the condition of ensuring the same cutting edge shape, the overall shape of the cutting insert 1 can be reduced, which is beneficial to the cutting insert 1. The overall size is reduced, the use of raw materials for the blade is reduced, and the cost is reduced.

Preferably, the chip flute surface 115 is closer to the second surface 12 than the restraining surface 116 as a whole, so that there is a larger chip processing space between the chip flute surface 115 and the first edge portion 1111, which is more convenient. Curl and discharge of chips.

Referring to FIG. 5 , in this embodiment, the rake face 114 further includes an extension face 1145 , and the chip flute face 115 is connected to the extension face 1145 to connect the first rake face 1141 and the third rake face 1143 .

The extension surface 1145 extends from the first rake surface 1141 toward the center hole 14 , and in the direction toward the central axis CL, the extension surface 1145 approaches the second surface 12 as it moves away from the first rake surface 1141 . In the direction extending along the first edge 111 , the extension surface 1145 is in contact with a part of the first rake surface 1141 , and is in contact with a part of the third rake surface 1143 , but is not in contact with the second rake surface 1142 catch.

In this embodiment, the chip flute surface 115 has a first end 1151 closest to the first corner 112 and a second end 1152 closest to the second corner 113 . The first end 1151 and the second end 1152 define the boundary of the chip flute surface 115 along the extending direction of the first edge 111 , the first end 1151 is connected to the first rake surface 1141 through the extending surface 1145 , and the second end 1152 The extension surface 1145 is in contact with the third front corner surface 1143 .

The projected length of the distance between the first end 1151 and the second end 1152 along the extending direction of the first edge 111 is L1, that is, the projected length of the chip flute surface 115 along the extending direction of the first edge 111 is L1 .

In some preferred embodiments, L1 is 1/7˜1/3 of the side length L0 of the first surface 11 , that is, L1/L0=1/7˜1/3. Under this design range, on the one hand, the chip flute surface 115 has sufficient length to achieve the expected chip breaking and chip removal effect, and on the other hand, the chip flute surface 115 will not occupy too much area of the first surface 11 . , so that the restraining surface 116 can have a sufficient area to ensure the locking effect of the cutting insert 1 on the shank 2 . In general, the chip processing effect and the restraining and locking effect can be balanced.

Referring to FIG. 5 to FIG. 8 , the chip flute surface 115 and the extension surface 1145 are enclosed to form a groove 118 that is concave toward the second surface 12 compared to the restraining surface 116 .

Referring to FIGS. 6 to 8 , the flute surface 115 and the extension surface 1145 are smoothly connected at the bottom of the groove 118 . 6 to 8 as a reference, when viewed from the first edge 111 toward the central axis CL, the chip flute surface 115 constitutes a rising portion of the groove 118, and the extension surface 1145 constitutes a concave Declined portion of groove 118 .

With reference to FIGS. 6 to 8 , the included angles α between different positions of the chip flute surface 115 and the plane where the restraint surface 116 is located are not exactly the same. a3. In the direction from the first end 1151 to the second end 1152, the inclination angle of the chip flute surface 115 relative to the restraining surface 116 changes gently, and the specific curved surface shape can be designed flexibly, but generally, the closer to the first end 1151 or the second end 1152, the smaller the included angle α between the chip flute surface 115 and the plane where the restraining surface 116 is located. At the three cross-sections shown in FIGS. 6 to 8 , the included angle α1 < the included angle α2 , and the included angle α3 < the included angle α2 .

Preferably, at different positions between the first end 1151 and the second end 1152, the variation range of the included angle α is: 0°<α<40°.

Similarly, the included angles β between different positions of the extension surface 1145 and the plane where the restraining surface 116 is located are not exactly the same. In the extending direction along the first edge 111 , the inclination angle of the extending surface 1145 relative to the restraining surface 116 changes gently, wherein the side of the extending surface 1145 close to the first edge 111 and the first front angle surface 1141 In contact with the third rake surface 1143, the extension surface 1145 is also connected with the first rake surface 1141 and the third rake surface 1143 through appropriate angles and shapes. The specific curved surface shape of the extension surface 1145 can be reasonably designed according to the actual situation.

Preferably, at different positions of the extending surface 1145 along the extending direction of the first edge 111 , the variation range of the included angle β is: 0°<β<35°.

6 to 8 , it can be seen that the bottom of the groove 118 formed by the intersection of the chip flute surface 115 and the extension surface 1145 is a curved surface with a different depth relative to the restraining surface 116 . Wherein, as shown in FIG. 5 , the bottom of the groove 118 has the deepest concave portion 1153 relative to the restraining surface 116 , that is, closest to the second surface 12 .

The most concave portion 1153 is the position where the chip flute surface 115 is closest to the second surface 12 relative to the restraining surface 116 , and the most concave portion 1153 is located between the first end 1151 and the second end 1152 . There is a first position from the first end 1151 to the most concave part 1153 and a second position closer to the most concave part 1153, the angle α between the chip flute surface 115 and the plane where the restraint surface 116 is located at the first position is smaller than the first position. The corresponding angle α at the two positions. In some embodiments, in the direction from the first end 1151 to the most concave portion 1153 , the included angle α between the chip flute surface 115 and the plane where the restraining surface 116 is located can be designed to gradually increase.

Preferably, in the direction extending along the first edge 111 , the most concave portion 1153 is closer to the first corner 112 than the junction P of the first edge portion 1111 and the transition edge portion 1113 . Since the first blade portion 1111 is disposed obliquely, and the closer it is to the transition blade portion 1113, the closer it is to the second surface 12. The groove 118 formed by the correspondingly disposed chip removal groove surface 115 and the extension surface 1145 can increase the chip removal space of this part of the first edge portion 1111 , and at the same time, the most concave part 1153 is closer to the first edge than the junction P. At the corner 112, correspondingly, at the position corresponding to the junction P, the chip removal groove surface 115 forms an upward slope relative to the most concave part 1153, which is more conducive to the export of chips, and reduces the chip removal effect while ensuring the chip removal effect. The chip groove surface 115 occupies the area of the first surface 11 , which can better ensure the area of the restraint surface 116 and improve the restraint effect.

In some embodiments, the projected length of the distance from the first end 1151 to the most concave portion 1153 along the extending direction of the first edge 111 is L2 , and the projected length L2 is preferably equal to the total projected length L1 of the chip flute surface 115 . 1/2～2/3, namely: L2/L1=1/2～2/3.

The first surface 11 is described in detail above. For the cutting insert 1 that can be used on both sides of the present embodiment, the second surface 12 may have the same structure as the first surface 11, and the two are rotationally symmetric, and can be Swap by flipping. The second surface 12 will not be described in detail here. When the cutting insert 1 is mounted on the tool holder 2, the first surface 11 or the second surface 12 can be selectively involved in cutting by adjusting the mounting method.

Referring to FIG. 2 , the outer peripheral surface 13 is connected between the first surface 11 and the second surface 12 . The outer peripheral surface 13 is surrounded by a plurality of side surfaces parallel to the central axis CL. According to the outer surface of the first surface 11 and the second surface 12 As for the extended shape of the edge, the outer peripheral surface 13 may include a flat surface and an arc surface, so as to be connected with the first surface 11 and the second surface 12 adaptively.

While the present invention has been described with reference to several exemplary embodiments, it is to be understood that the terminology used is of description and illustration, and not of limitation. Since the invention can be embodied in many forms without departing from the spirit or spirit of the invention, it is to be understood that the above-described embodiments are not limited to any of the foregoing details, but are to be construed broadly within the spirit and scope defined by the appended claims Therefore, all changes and modifications that come within the scope of the claims or their equivalents should be covered by the appended claims.

Claims (12)

1. A cutting insert having: a first surface, which is a rotationally symmetric polygon; a second surface on the opposite side of the first surface; an outer peripheral surface located between the first surface and the second surface; and a central axis passing through the center of the first surface and the center of the second surface; It is characterized by: The first surface includes: first edge; a first corner, connecting the first edge; The second corner is connected to the first edge; a rake surface, disposed along the first edge, and approaching the second surface as it moves away from the first edge; a chip flute surface disposed along the rake face and away from the second surface as it moves away from the rake face; and a restraining surface, disposed along the rake surface and the chip flute surface, closer to the second surface than the first edge, and perpendicular to the central axis; The first edge includes: a first blade extending from the first corner to the second corner and approaching the second surface as it approaches the second corner; a second blade portion extending linearly from the second corner to the first corner, and approaching the second surface as it approaches the first corner; and a transition edge, connecting the first edge and the second edge, and approaching the second surface as it approaches the first corner; When looking directly at the outer peripheral surface, the inclination angle of the transition blade portion is greater than the inclination angle of the second blade portion; The front corner surface includes: a first rake face, arranged along the first blade; a second rake face disposed along the second edge portion; and a third rake face, arranged along the transition blade; The chip flute surface connects the first rake surface and the third rake surface, and is away from the second rake surface. 2. The cutting insert of claim 1, wherein the flute surface is closer to the second surface than the restraint surface. 3. The cutting insert of claim 2, wherein the flute surface has a first end closest to the first corner and a second end closest to the second corner, the first end One end is connected with the first rake surface, and the second end is connected with the third rake surface; The most concave part, the most concave part is located between the first end and the second end. 4 . The cutting insert according to claim 3 , wherein, in a direction extending along the first edge, the most concave portion is compared with the difference between the first edge portion and the transition edge portion. 5 . The junction is closer to the first corner. 5 . The cutting insert according to claim 4 , wherein the distance from the first end to the second end in a direction along the extending direction of the first edge when viewed from the direction facing the restraining surface. 6 . The projected length is L1, and the projected length of the distance from the first end to the most concave portion along the extending direction of the first edge is L2, and L2/L1=1/2˜2/3. 6 . The cutting insert according to claim 3 , wherein the included angle between the chip flute surface and the plane where the restraining surface is located is α, and the angle from the first end to the most concave part is α. 7 . There is a first position and a second position closer to the most concave portion, and the included angle α at the first position is smaller than the included angle α at the second position. 7 . The cutting insert according to claim 6 , wherein, at different positions between the first end and the second end, the variation range of the included angle α is: 0°<α<40° . 8. The cutting insert according to claim 2, wherein the rake face further comprises an extension face connected between the first rake face and the chip flute face; In the axial direction, the extension surface approaches the second surface as it moves away from the first rake surface. 9 . The cutting insert according to claim 8 , wherein the included angle between the extending surface and the plane where the restraining surface is located is β, and in the extending direction of the extending surface along the first edge. 10 . At different positions of , the variation range of the included angle β is: 0°<β<35°. 10 . The cutting insert according to claim 1 , wherein the projected length of the chip flute surface along the extending direction of the first edge is equal to the length of the edge of the first surface. 11 . 1/7～1/3. 11. The cutting insert according to any one of claims 1-9, wherein the length of the first edge portion is greater than the length of the second edge portion. 12. A cutting tool, comprising a tool holder and the cutting insert according to any one of claims 1-11 mounted on the tool holder.

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