Fixation member and cutting tool

Abstract

To provide a fixation member which can achieve down-sizing of itself while ensuring sufficient strength, and further, can fix a cutting insert with high strength, and a cutting tool.SOLUTION: A fixation member 50, which presses and fixes a cutting insert 40 located on an insert attachment part 12 of a tool body 10, has: a fixation member body 51 having a pressing part 55 which presses the cutting insert 40; a fitting projection 52 which is projected from a bottom of the fixation member body 51, and is fitted into a fitting hole 21 formed in the tool body 10; and an engagement recess 61 which is formed around the fitting projection 52, and with which a tip of fixation screw 23 screwed into a female screw 22 communicating with a fitting hole 21 of the tool body 10 is engaged. The fitting projection 52 is pulled in the fitting hole 21 by the fixation screw 23 engaging with the engagement recess 61, whereby the pressing part 55 presses and fixes the cutting insert 40.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a fixing member and a cutting tool. [Background technology]

[0002] A cutting tool for cutting a workpiece includes a tool body, a cutting insert disposed on a mounting portion of the tool body, and a fixing member for fixing the cutting insert to the tool body (see, for example, Patent Document 1). In this cutting tool, a screw is inserted into a through hole formed in the fixing member, and the screw is screwed into a screw hole in the tool body and tightened, whereby the cutting insert is pressed and fixed to the tool body by the fixing member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 034339 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned cutting tool, since the fixing member has a through hole for passing the screw therethrough, it is necessary to provide a sufficient thickness around the through hole to ensure strength, and also to ensure a surface of sufficient area for the head of the screw to engage with, which inevitably results in an increase in the size of the fixing member.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a fixing member and a cutting tool that can be miniaturized while ensuring sufficient strength, and can fix a cutting insert with high strength. [Means for solving the problem]

[0006] A fixing member according to one embodiment of the present invention is a fixing member that presses and fixes a cutting insert placed in an insert mounting portion of a tool body, and has a fixing member main body having a pressing portion that presses the cutting insert, a fitting protrusion that protrudes from the bottom of the fixing member main body and fits into a fitting hole formed in the tool body, and an engagement recess that is formed on the circumferential surface of the fitting protrusion and engages with a tip of a pressing member that is inserted into a hole portion communicating with the fitting hole of the tool body, and is configured so that the pressing portion presses and fixes the cutting insert when the fitting protrusion is pulled into the fitting hole by the pressing member engaging with the engagement recess.

[0007] The fixing member of the above configuration does not require a through hole for passing the screw or a large surface for engaging with the head of the screw, making it possible to reduce the size. This can reduce the cause of interference with the workpiece during cutting processing such as internal diameter processing, and can expand the range of application. In addition, the space for discharging chips can be expanded, reducing the frequency of sudden breakage due to chip clogging.

[0008] The engaging recess may have a contact protrusion having a spherical convex surface formed at a bottom portion with which the tip surface of the pressing member abuts.

[0009] The fitting projection may have a plurality of engaging recesses formed at various positions in the circumferential direction.

[0010] The hole may be an internal thread, and a fixing screw may be screwed into the internal thread as the pressing member.

[0011] A cutting tool according to one embodiment of the present invention comprises the above-mentioned fixing member, a tool body having an insert mounting portion in which a cutting insert is disposed and a fixing member mounting portion to which the fixing member is assembled, and a cutting insert that is disposed in the insert mounting portion and pressed and fixed by the fixing member, and the fixing member mounting portion has an engagement hole into which the engagement protrusion of the fixing member is fitted, a hole portion communicating with the inner surface of the engagement hole, and a pressing member that is inserted into the hole portion and has a tip that engages with an engagement recess of the fixing member. Effect of the Invention

[0012] According to the present invention, there are provided a fixing member and a cutting tool that can be made compact while ensuring sufficient strength, and that can fix a cutting insert with high strength. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a side view of a cutting tool according to the present embodiment. [Diagram 2] FIG. 2 is a perspective view of the tip of the cutting tool according to this embodiment. [Diagram 3] FIG. 3 is a schematic side view of a clamping portion of the cutting insert. [Figure 4] FIG. 4 is a schematic perspective view of a clamping portion of the cutting insert as viewed from behind. [Diagram 5] FIG. 5 is a perspective view of the tip of the tool body with the cutting insert placed in the insert attachment portion. [Figure 6] FIG. 6 is a plan view of the tip of the tool body with the cutting insert disposed in the insert attachment portion. [Figure 7] FIG. 7 is a side view of the fixing member. [Figure 8] FIG. 8 is a perspective view of the fixing member. [Figure 9] FIG. 9 is a front view of the fixing member. [Figure 10] FIG. 10 is a perspective view of the fixing member as viewed from the lower rear. [Figure 11] FIG. 11 is a perspective view seen from the rear surface side of a fixing member having a coil spring attached to the tip of a fitting projection. [Figure 12] FIG. 12 is a plan view of the fixing member illustrating the shape of the fitting projection of the fixing member. [Figure 13] FIG. 13 is a perspective view of the fixing member, showing a state in which the fixing screw is engaged with the engaging recess formed in the fitting protrusion of the fixing member. [Figure 14] FIG. 14 is a side view of a portion of a fixing member having a guide protrusion in front of a fitting projection. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. (cutting tools) 1 to 4, a cutting tool 100 according to this embodiment has a tool body 10 and a cutting insert 40, and the tool body 10 is provided with a fixing member 50 and a fixing screw 23. This cutting tool 100 is a turning tool in which the cutting insert 40 is attached to the tip of the tool body 10 and performs external cutting or internal cutting on a rotating workpiece by the cutting insert 40 at the tip of the tool body 10. The cutting insert 40 is pressed and fixed by the fixing member 50 of the tool body 10.

[0015] (Tool body) The tool body 10 is formed in a prismatic shape, and the cutting insert 40 is attached to the tip of the tool body 10. The tool body 10 has an insert attachment portion 12 at its tip, and the cutting insert 40 is attached to the insert attachment portion 12. The tool body 10 is formed from a metal material such as steel. As the material of the tool body 10, for example, alloy tool steel (SKS5), die steel (SKD61), maraging steel, etc., which have elasticity and are not easily plastically deformed, are preferable. The shape of the tool body 10 is not limited to a prismatic shape.

[0016] The insert mounting portion 12 has a mounting surface 13 and a side wall surface 14 that is provided substantially vertically on the rear side of the mounting surface 13. A cutting insert 40 is placed on the mounting surface 13 of the insert mounting portion 12 via a shim 15. Note that a structure in which the cutting insert 40 is placed on the mounting surface 13 without providing the shim 15 may also be used.

[0017] The tool body 10 has a fixed member mounting portion 16 on the rear side of the insert mounting portion 12, and a fixed member 50 is attached to this fixed member mounting portion 16. The fixed member mounting portion 16 has a mounting surface 17 consisting of a flat surface that is connected to the side wall surface 14 of the insert mounting portion 12. The fixed member mounting portion 16 also has a sliding surface 18 on the rear side of the mounting surface 17. This sliding surface 18 is an inclined surface that gradually slopes downward from the mounting surface 17 side toward the rear.

[0018] As shown in Figs. 5 and 6, the fixing member mounting portion 16 has a fitting hole 21 and a female screw (hole portion) 22. The fitting hole 21 is formed perpendicular to the mounting surface 17. The female screw 22 opens on the side of the fitting hole 21 and is formed obliquely toward the fitting hole 21. The female screw 22 communicates with the fitting hole 21 on the inner circumferential surface. A fixing screw (pressing member) 23 is screwed into the female screw 22 from the upper side of the fixing member mounting portion 16, and its tip protrudes into the fitting hole 21. A hollow set screw is used as the fixing screw 23. In this example, a structure in which the fixing screw 23 is screwed into the female screw 22 is illustrated, but instead of the female screw 22, a hole portion communicating with the fitting hole 21 may be formed, and a pressing member such as a pin may be inserted into the hole portion by operating a cam or lever.

[0019] Furthermore, a guide recess 25 is formed on the inner circumferential surface of the fitting hole 21. This guide recess 25 is provided on the opposite side to the insert mounting portion 12, and is formed in a spherical concave shape. Furthermore, an outflow port 26 is formed on the inner circumferential surface of the fitting hole 21. This inflow port 26 is also provided on the opposite side to the insert mounting portion 12, and is provided lower than the guide recess 25.

[0020] As shown in FIG. 1, a tool body 10 having an insert mounting portion 12 and a fixing member mounting portion 16 at its tip has a main coolant passage 31, branch coolant passages 32, 33, and multiple coolant discharge passages 34 therein.

[0021] The main coolant passage 31 is formed along the longitudinal direction of the tool body 10. The main coolant passage 31 has a plurality of inlets 35, 36, and 37. The inlet 35 is formed on the rear end surface of the tool body 10, the inlet 36 is formed on the bottom surface at the middle in the longitudinal direction of the tool body 10, and the inlet 37 is formed on the bottom surface at the tip side of the tool body 10. The main coolant passage 31 is supplied with coolant from any one of the inlets 35, 36, and 37, and the inlets 35, 36, and 37 that are not used for supplying coolant are sealed with enamel set screws or the like.

[0022] The coolant branch passage 32 is formed at the upper part on the tip side of the tool body 10, and one end thereof is connected to the main coolant passage 31. The other end of this coolant branch passage 32 is connected to the fitting hole 21, and its opening portion serves as the outlet 26. The coolant supplied to the main coolant passage 31 is sent to this coolant branch passage 32. Note that the fluid supplied to the main coolant passage 31 is not limited to coolant, and various lubricants and coolants can be used, and mist or air may also be supplied.

[0023] The coolant branch passage 33 is formed at the lower part on the tip side of the tool body 10, and one end of the coolant branch passage 33 is connected to the main coolant passage 31. The other end of the coolant branch passage 33 is connected to one end of a plurality of coolant discharge passages 34. The other end of the coolant discharge passage 34 opens near the tip of the tool body 10, and this opening portion is a discharge port 34a. The coolant supplied to the main coolant passage 31 is sent to the coolant branch passage 33. The coolant sent to the coolant branch passage 33 passes through the coolant discharge passage 34 and is discharged from the discharge port 34a, and cools and lubricates the vicinity of the flank face of the cutting insert 40.

[0024] (Cutting insert) 5 and 6, the cutting insert 40 attached to the insert attachment portion 12 of the tool body 10 is formed in, for example, a flat, substantially triangular three-dimensional shape. The cutting insert 40 has end faces 43 on the front and back, and each end face 43 has three corner portions 41. The cutting insert 40 also has a fixing hole portion 42 in its center.

[0025] The cutting insert 40 has substantially triangular end faces 43 facing each other and three peripheral side faces 44 connecting these end faces 43. In this cutting insert 40, the vicinity of each corner portion 41 on the ridge line 45 between each end face 43 and the peripheral side face 44 is formed as a cutting edge 46.

[0026] The cutting insert 40 is placed and fixed on the insert attachment portion 12 of the tool body 10 with one of the end faces 43 facing upward and one of the three corner portions 41 facing the tip direction. In this way, the cutting insert 40 is capable of cutting at a total of six locations by using one of the three corner portions 41, each having a cutting edge 46, on each end face 43 facing the tip direction.

[0027] (Fixing member) 7 to 11, the fixing member 50 has a fixing member main body 51 and a fitting protrusion 52. The fitting protrusion 52 extends downward from the bottom of the fixing member main body 51.

[0028] The fixing member body 51 has a pressing portion 55 on the tip side from the fitting protrusion 52, and a pressing protrusion 56 protruding downward is formed on this pressing portion 55. This pressing protrusion 56 is a protrusion for fixing the cutting insert 40, and may have any shape as long as it can press the inner circumferential surface of the fixing hole portion 42 of the cutting insert. In addition, the fixing member body 51 has a sliding surface 58 on the rear end portion 57 side from the fitting protrusion 52, which gradually slopes backward as it goes downward.

[0029] The fitting projection 52 is formed in a cylindrical shape. The fitting projection 52 has engagement recesses 61 on both sides. The engagement recesses 61 are formed in a concave shape that gradually inclines toward the center toward the protruding direction of the fitting projection 52. A contact protrusion 62 that protrudes in a spherical convex shape is formed at the bottom of the engagement recess 61. In addition, a guide protrusion 63 in a spherical convex shape is formed near the base on the rear side of the fitting projection 52. Furthermore, the fitting projection 52 has an annular recess 65 at its tip, and a coil spring 66 is fitted and attached to the annular recess 65. In addition, an annular O-ring 67 is attached to the base of the fitting projection 52.

[0030] 12, the fitting protrusion 52 has a tip 52a formed in a circular shape with an outer diameter D1. In contrast, the base end 52b side of the fitting protrusion 52 is formed in an elliptical shape having a major axis D1 and a minor axis D2, with the front-to-rear direction of the fixing member 50 being the minor axis direction. As a result, the dimension of the fitting protrusion 52 in the front-to-rear direction becomes gradually smaller from the tip 52a to the base end 52b.

[0031] The fixed member 50 has a coolant introduction passage 71, a coolant discharge passage 72, and a coolant reservoir 73. One end of the coolant introduction passage 71 opens on the tip side of the guide protrusion 63 on the rear side of the fitting protrusion 52, and this opening portion is an inlet 74. The coolant introduction passage 71 is formed from the inlet 74 toward the fixed member main body 51 while curving upward on the fitting protrusion 52. In this example, two coolant discharge passages 72 are formed. These coolant discharge passages 72 are formed, for example, in parallel along the front-rear direction on the tip side of the fixed member main body 51, and open at the tip of the fixed member main body 51. The opening portions of these coolant discharge passages 72 are discharge ports 72a. The coolant reservoir 73 is formed at a position above the fitting protrusion 52 in the fixed member main body 51. The coolant introduction passage 71 and the coolant discharge passage 72 are each connected to the coolant reservoir 73. The coolant reservoir 73 has a flow passage cross section larger than the coolant introduction flow passage 71 and the coolant discharge flow passage 72. Note that the two coolant discharge flow passages 72 are not limited to being arranged in parallel.

[0032] (Fixing cutting inserts) Next, a case where the cutting insert 40 disposed in the insert attachment portion 12 of the tool body 10 is fixed by the fixing member 50 will be described.

[0033] First, with respect to the tool body 10 with the cutting insert 40 disposed in the insert mounting portion 12, the fitting protrusion 52 of the fixing member 50 is inserted into the fitting hole 21 of the fixing member mounting portion 16, and the fixing member body 51 is disposed on the upper part of the fixing member mounting portion 16. Then, the pressing protrusion 56 formed on the pressing portion 55 of the fixing member body 51 is fitted into the fixing hole 42 of the cutting insert 40. At this time, the coil spring 66 at the tip of the fitting protrusion 52 is abutted against the bottom 21a of the fitting hole 21.

[0034] In this state, the fixing screw 23 is screwed into the female thread 22 of the fixing member mounting portion 16 of the tool body 10. Then, as shown in Fig. 13, the tip of the fixing screw 23 protrudes into the fitting hole 21 and is inserted into one of the engagement recesses 61 formed in the fitting protrusion 52, and abuts against the contact protrusion 62 formed at the bottom of the engagement recess 61. Then, by further screwing in the fixing screw 23, the fitting protrusion 52 is pulled into the fitting hole 21 against the biasing force of the coil spring 66 by the fastening force of the fixing screw 23. As a result, the fixing member 50 is pressed toward the fixing member mounting portion 16 of the tool body 10. Then, the cutting insert 40 is pressed against the shim 15 of the insert mounting portion 12 of the tool body 10 by the pressing force F1 by the pressing portion 55 of the fixing member 50.

[0035] In addition, by pressing the fixing member 50 against the fixing member mounting portion 16, the sliding surface 58 of the fixing member main body 51 comes into contact with and slides against the sliding surface 18 of the tool body 10. Then, the fixing member 50 is pulled toward the rear of the tool body 10 by a component force F3 of the reaction force F2 from the sliding surface 18 of the tool body 10. As a result, the pressing protrusion 56 fitted into the fixing hole portion 42 of the cutting insert 40 moves rearward while abutting against the inner peripheral surface of the fixing hole portion 42. Therefore, the pressing protrusion 56 of the fixing member 50 pulls the cutting insert 40 toward the rear side of the insert mounting portion 12 of the tool body 10 and presses it against the side wall surface 14. In this way, the cutting tool 100 is provided with a double clamp type fixing method in which the fixing member 50 presses two points, the upper end surface 43 of the cutting insert 40 and the inner peripheral surface of the fixing hole portion 42.

[0036] Here, the fitting protrusion 52 of the fixed member 50 has an elliptical base end 52b smaller in the front-rear direction than the tip 52a. Therefore, in the front-rear direction of the fixed member 50, a gap is formed between the fitting protrusion 52 and the fitting hole 21, which gradually becomes larger toward the base end 52b of the fitting protrusion 52. As a result, when the fitting protrusion 52 is pulled into the fitting hole 21 by the fixing screw 23, the fixed member 50 is displaced smoothly toward the rear of the tool body 10. The fitting protrusion 52 may be elliptical in shape with the front-rear direction of the fixed member 50 being the minor axis direction over the entire length. In this case, by making the minor axis dimension on the base end 52b side smaller than the minor axis on the tip 52a side, a gap is formed between the fitting protrusion 52 and the fitting hole 21, which gradually becomes larger toward the base end 52b of the fitting protrusion 52, in the front-rear direction of the fixed member 50, and the fixed member 50 fitted in the fitting hole 21 can be displaced smoothly toward the rear of the tool body 10.

[0037] In addition, in a clamped state in which the cutting insert 40 is fixed to the insert attachment portion 12, the guide protrusion 63 formed on the fitting protrusion 52 of the fixing member 50 is fitted into the guide recess 25 formed in the fitting hole 21 of the tool body 10. As a result, the fixing member 50 is prevented from rotating around the axis of the fitting protrusion 52 of the fixing member 50 by the guide protrusion 63 and the guide recess 25 which fit together. Therefore, the fluctuation of the fixing member 50 during cutting processing by the cutting insert 40 of the cutting tool 100 is suppressed, and good cutting processing by the cutting insert 40 is possible.

[0038] 14, a guide protrusion 63 may also be provided on the front side of the fitting protrusion 52 of the fixing member 50. In this case, a guide recess 25 into which the guide protrusion 63 provided on the front side of the fitting protrusion 52 can be fitted is provided on the insert attachment portion 12 side of the fitting hole 21. This can further enhance the anti-rotation effect around the axis of the fitting protrusion 52 of the fixing member 50.

[0039] In addition, in a clamped state in which the cutting insert 40 is fixed to the insert mounting portion 12, the O-ring 67 attached to the base of the fitting projection 52 of the fixing member 50 is in close contact with the mounting surface 17 of the fixing member mounting portion 16 of the tool body 10. This provides a seal between the bottom of the fixing member 50 and the mounting surface 17 of the fixing member mounting portion 16.

[0040] Furthermore, in a clamped state in which the cutting insert 40 is fixed to the insert attachment portion 12, the inlet 74 of the coolant introduction passage 71 formed in the fitting protrusion 52 of the fixed member 50 is communicated with the outlet 26 of the coolant branch passage 32 formed in the fitting hole 21 of the tool body 10. As a result, the coolant sent from the main coolant passage 31 to the coolant branch passage 33 is sent to the coolant introduction passage 71 of the fixed member 51. The coolant sent to the coolant introduction passage 71 is then sent to the coolant discharge passage 72 via the coolant reservoir 73 and discharged from the discharge port 72a at the tip of the fixed member 50. As a result, the coolant discharged from the discharge port 34a at the tip of the tool body 10 and the coolant discharged from the discharge port 72a at the tip of the fixed member 50 are sprayed onto the cutting portion by the cutting insert 40. As a result, the cutting portion by the cutting insert 40 is well cooled and lubricated. Here, a coolant reservoir 73 having a large flow passage cross section is provided between the coolant inlet flow passage 71 and the coolant outlet flow passage 72. This reduces pressure loss of the coolant when it is sent from the coolant inlet flow passage 71 to the coolant outlet flow passage 72 having a small inner diameter, and allows the coolant to be discharged well from the outlet port 72a.

[0041] (Removing the cutting insert) Next, a case where the cutting insert 40 fixed to the insert attachment portion 12 of the tool body 10 by the fixing member 50 is removed will be described.

[0042] To remove the cutting insert 40, first, the fixing screw 23 that fixes the fixing member 50 is loosened. Then, the fixing screw 23 is pulled out from the engagement recess 61 of the fixing member 50. Then, the fixing member 50 is pushed up in a direction away from the fixing member mounting portion 16 of the tool body 10 by the elastic force of the coil spring 66 at the tip of the fitting protrusion 52. This releases the fixing of the cutting insert 40 by the fixing member 50. In this way, when the fixing member 50 is pushed up by the coil spring 66, the guide protrusion 63 of the fitting protrusion 52 that was engaged with the guide recess 25 of the fitting hole 21 slides with the guide recess 25. As a result, the rear side of the fixing member 50 is guided along the contact surface between the guide protrusion 63 and the guide recess 25, and the rear part of the fixing member 50 is smoothly pushed up. Therefore, the fixing member 50 whose rear part is pushed up can be easily gripped and removed from the fixing member mounting portion 16 of the tool body 10.

[0043] As described above, the fixing member 50 according to this embodiment does not require a through hole for passing a screw or a large surface for engaging with the head of the screw, making it possible to reduce the size. This can reduce the cause of interference with the workpiece during cutting such as internal diameter processing, and can expand the range of application. In addition, the space for discharging chips can be expanded, reducing the frequency of sudden defects caused by chip clogging.

[0044] In addition, since the tip surface of the fixing screw 23 abuts against the spherical convex contact protrusion 62 , the fastening force of the fixing screw 23 can be transmitted to the fitting projection 52 without bias, and the fixing screw 23 can be pulled into the fitting hole 21 .

[0045] Moreover, since the engagement recesses 61 are formed at a plurality of locations (two locations on both sides in this example) in the circumferential direction of the fitting projection 52, any one of the engagement recesses 61 can be used according to convenience, allowing for left and right use as desired. [Explanation of symbols]

[0046] 10 Tool body 12 Insert mounting part 21 Fitting hole 22 Female thread (hole) 23 Fixing screw (pressure member) 40 Cutting insert 50 Fixing member 51 Fixing member body 52 Fitting protrusion 55 Pressing part 61 Engagement recess 62 Contact protrusion 100 cutting tools

Claims

1. A fixing member that presses and fixes a cutting insert disposed in an insert mounting portion of a tool body, A fixing member body having a pressing portion that presses the cutting insert; a fitting protrusion that protrudes from a bottom of the fixing member body and is fitted into a fitting hole formed in the tool body; an engagement recess formed on a peripheral surface of the fitting projection, the engagement recess engaging a tip of a pressing member inserted into a hole communicating with the fitting hole of the tool body; having The fitting projection is pulled into the fitting hole by the pressing member engaged with the engagement recess, whereby the pressing portion presses and fixes the cutting insert. Fixing member.

2. The engagement recess has a bottom portion with which the tip surface of the pressing member comes into contact, the bottom portion being formed with a spherical convex contact protrusion. The fixing member according to claim 1 .

3. The fitting projection has the engagement recesses formed at a plurality of locations in the circumferential direction. The fixing member according to claim 1 .

4. The hole portion is an internal thread, and a fixing screw is screwed into the internal thread as the pressing member. The fixing member according to claim 1 .

5. A fixing member according to any one of claims 1 to 4, a tool body having an insert mounting portion in which the cutting insert is disposed and a fixing member mounting portion to which the fixing member is attached; a cutting insert that is disposed in the insert attachment portion and is pressed and fixed by the fixing member; Equipped with The fixing member attachment portion is a fitting hole into which the fitting protrusion of the fixing member is fitted; a hole portion communicating with an inner circumferential surface of the fitting hole; a pressing member that is inserted into the hole and has a tip that engages with the engaging recess of the fixing member; having cutting tools.

Images