JP2015205329A - Cutting tool that bonds superhard alloy and steel material, and method of manufacturing the cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool in which bond strength is sufficiently secured.SOLUTION: In a state that an intermediate member 40 is interposed, a member 30 for a cutting blade and a member 20 for a shank are pressure-bonded after being relatively rotated so that bonding of the member 30 for a cutting blade and the intermediate member 40, and bonding of the intermediate member 40 and the member 20 for a shank are carried out. Since heating of the intermediate member 40 is carried out only once, the alteration of the intermediate member 40 affected by heat can be suppressed unlike in the case where both of the bonding are carried out separately (a two-stage friction welding, for example), and, accordingly, the bonding strength can be sufficiently secured.

Description

  The present invention relates to a cutting tool.

  In a cutting tool, a technique for improving cutting performance and reducing product cost by forming a first member including a cutting edge from cemented carbide and forming a second member including a shank portion from a steel material is known. ing.

  In this case, for joining the first member and the second member, methods using brazing or friction welding are known. However, in these methods, the difference in thermal expansion coefficient between the cemented carbide and the steel material is known. As a result, cracks due to residual stress are likely to occur.

  On the other hand, Patent Document 1 discloses a technique for suppressing the occurrence of cracks by joining the first member and the second member via an intermediate member. That is, in Patent Document 1, a steel shank member 13 (second member) and an intermediate member 25 (intermediate member) are joined by first stage friction welding, and then the composite member obtained by this joining is obtained. 31 intermediate member 25 and cemented carbide cutting blade member 11 (first member) are joined by friction welding in the second stage.

JP-A-2004-216410 (for example, paragraphs 0014 to 0023, FIGS. 1 to 7 and the like)

  However, in the technique of Patent Document 1 in which friction welding is performed in the first and second stages as described above, the intermediate member 25 (intermediate member) is altered due to the influence of heat in the first stage friction welding. Therefore, the intermediate member 25 does not sufficiently wrap around the surface of the cutting blade member 11 (first member) during the second stage friction welding, and an unwelded portion is likely to occur on the outer peripheral portion. Therefore, there has been a problem that it is difficult to ensure sufficient bonding strength.

  The present invention was made to solve the above-described problems, and when the first member formed of cemented carbide and the second member formed of steel material are joined via an intermediate member, An object of the present invention is to provide a cutting tool and a method for manufacturing the cutting tool in which the bonding strength is sufficiently ensured.

  In order to achieve this object, a cutting tool according to claim 1 includes a first member made of cemented carbide and having a cutting edge, a second member made of steel and having a shank portion, the first member and the first member. A cutting tool including an intermediate member interposed between the axial end surfaces of two members, wherein the intermediate member includes a fitting portion formed on the axial end surface, and the first member or the second member. One of the members includes a fitted portion formed on an axial end surface that can be fitted to the fitting portion of the intermediate member, and the fitting portion of the intermediate member and the first member or the second member In the other of the first member or the second member on the axial end surface of the intermediate member on the side opposite to the side on which the fitting portion is formed while being fitted with the fitted portion in one of them With the end face in the axial direction in contact with the first member, By beauty second member is pressed against the axial direction after being relatively rotated around the axis, the joining of the the junction of the first member and the intermediate member intermediate member and the second member is performed.

  The method for manufacturing a cutting tool according to claim 2 includes a first member formed of cemented carbide and having a cutting edge, a second member formed of steel and having a shank portion, and shafts of the first member and the second member. A cutting tool manufacturing method comprising an intermediate member interposed between directional end faces, wherein a fitting portion is formed on an axial end face of the intermediate member, and the first member or the second member A forming step of forming a fitted portion that can be fitted into a fitting portion of the intermediate member on one axial end surface, and the fitting portion and the first member or the first member in the intermediate member formed by the forming step A fitting step for fitting a fitted portion in one of the two members, and the fitted portion in one of the first member or the second member and the fitting in the intermediate member by the fitting step After fitting the joint, the intermediate An abutting step of abutting an axial end surface opposite to the side on which the fitting portion of the material is formed with an axial end surface of the other of the first member and the second member, and the abutting step From the state in which the axial end surface of the intermediate member opposite to the side on which the fitting portion is formed and the other axial end surface of the first member or the second member are in contact with each other, A joining step of joining the first member and the intermediate member and joining the intermediate member and the second member by pressing the one member and the second member relative to each other around the axis and then pressing them in the axial direction. Prepare.

  The cutting tool or the cutting tool manufacturing method according to claim 3 is the cutting tool according to claim 1 or the cutting tool manufacturing method according to claim 2, wherein the fitting portion is a cylindrical convex coaxial with the intermediate member. Formed as a portion, and the fitted portion is formed as a concave portion having a circular cross section having an inner diameter smaller than the outer diameter of the convex portion that is coaxial with one of the first member and the second member. Alternatively, the fitting portion is formed as a concave portion having a circular cross section coaxial with the intermediate member, and the fitted portion is coaxial with one of the first member and the second member, and the inner diameter of the concave portion It is formed as a cylindrical protrusion having a larger outer shape.

  The cutting tool or the cutting tool manufacturing method according to claim 4 is the cutting tool or the cutting tool manufacturing method according to claim 3, wherein the fitting portion is formed as a concave portion, and the fitting portion is a convex portion. Formed as.

  The cutting tool or the cutting tool manufacturing method according to claim 5 is the cutting tool or the cutting tool manufacturing method according to any one of claims 1 to 4, wherein the fitted portion is formed on the second member. .

  The cutting tool or the cutting tool manufacturing method according to claim 6 is the cutting tool or the cutting tool manufacturing method according to any one of claims 1 to 5, wherein the cemented carbide is mainly composed of WC and contains Co. The amount is set to 5 wt% or more and 16 wt% or less, and the hardness is set to 89 HRA or more and 95 HRA or less.

  The cutting tool or the cutting tool manufacturing method according to claim 7 is the cutting tool or cutting tool manufacturing method according to any one of claims 1 to 6, wherein the intermediate member is formed of a Co-Ni-Fe alloy. , At least the Co content is set to 5 wt% or more and 40 wt% or less, and the Ni content is set to 20 wt% or more and 50 wt% or less.

  According to the cutting tool according to claim 1, the first member and the second member are pressed against each other after the first member and the second member are relatively rotated in a state where the intermediate member is interposed, so that the joining of the first member and the intermediate member and the intermediate member are performed. And the second member is joined, and the intermediate member is heated once, so that the intermediate member is compared with the case where both joints are performed separately (for example, in the case of two-stage friction welding). Can be suppressed from being affected by heat, and the joint strength can be sufficiently secured accordingly.

  According to the method for manufacturing a cutting tool according to claim 2, in the joining step, after the first member and the second member are relatively rotated with the intermediate member interposed between the first member and the second member, the pressure contact is performed. By doing so, since the joining of the first member and the intermediate member and the joining of the intermediate member and the second member are performed, the heating of the intermediate member can be performed once. Therefore, compared with the case where both joinings are performed separately (for example, when performing two-stage friction welding), the intermediate member can be prevented from being deteriorated by the influence of heat, and the joint strength is sufficiently increased. A secured cutting tool can be manufactured. Moreover, compared with the case of two-stage friction welding, a man-hour can be reduced and reduction of manufacturing cost can be aimed at.

  In this case, since the fitting step for fitting the fitting portion and the fitted portion formed in the forming step is provided before the abutting step, before the abutting step, one of the first member and the second member is connected. It is possible to form a complex in which the intermediate member is coupled by fitting, and accordingly, the work in the contact process can be facilitated. In addition, since one of the first member or the second member and the intermediate member are fitted, the intermediate member can be prevented from being displaced with respect to the first member and the second member in the joining step.

  According to the cutting tool or the manufacturing method of the cutting tool according to claim 3, in addition to the effect exerted by the cutting tool according to claim 1 or the cutting tool manufacturing method according to claim 2, the fitting portion and the fitted portion include Since each of the intermediate member and the first member or the second member is formed as a coaxial cylindrical convex portion or a circular concave portion, the shapes of the fitting portion and the fitting portion are simplified, and Manufacturing cost can be reduced.

  In addition, the fitting portion and the fitted portion are coaxial with one of the intermediate member and the first member or the second member, so that the amount of pressure contact when the first member and the second member are pressed against each other can be stabilized. It can be secured. Furthermore, since the outer diameter of the convex portion is made larger than the inner diameter of the concave portion, it is possible to prevent the fitting portion and the fitting portion from being disengaged, and to relatively rotate the first member and the second member. The driving force at the time can be transmitted in an appropriate state.

  According to the cutting tool or the manufacturing method of the cutting tool according to claim 4, in addition to the effect exerted by the cutting tool or the manufacturing method of the cutting tool according to claim 3, the fitting portion is formed as a recess, and the fitted portion is Since it is formed as a convex part, that is, a concave part is formed in the intermediate member, the thickness (axial dimension) of the intermediate member after being pressed in the axial direction can be made thin (small), and accordingly, the cutting tool as a whole The strength of can be secured.

  According to the cutting tool or the manufacturing method of the cutting tool according to claim 5, in addition to the effect exhibited by the cutting tool or the manufacturing method of the cutting tool according to any one of claims 1 to 4, the fitted portion is the second member. Therefore, the object to be processed can be made of steel, and the processing to cemented carbide can be made unnecessary. Therefore, it is possible to reduce the number of processing steps and reduce the manufacturing cost.

  According to the cutting tool or the manufacturing method of the cutting tool according to claim 6, in addition to the effect exerted by the cutting tool or the manufacturing method of the cutting tool according to any one of claims 1 to 5, the cemented carbide mainly includes WC. As a component, the Co content is set to 5 wt% or more and 16 wt% or less, and the hardness is set to 89 HRA or more and 95 HRA or less, so that the cutting performance can be improved.

  According to the cutting tool or the manufacturing method of the cutting tool according to claim 7, in addition to the effect exerted by the cutting tool or the manufacturing method of the cutting tool according to any one of claims 1 to 6, the intermediate member is made of Co-Ni-. It is made of Fe alloy, and at least Co content is set to 5 wt% or more and 40 wt% or less, and Ni content is set to 20 wt% or more and 50 wt% or less. Further, by making the elongation appropriate, it is possible to suppress the generation of residual stress and to ensure the deformability when pressed in the axial direction. As a result, sufficient bonding strength can be ensured.

It is a front view of the cutting tool in a 1st embodiment. (A) to (c) is a front view of a friction welding mechanism, and (d) is a front view of a shank member, a cutting blade member, and an intermediate member. (A) is a side view of the intermediate member, (b) is a cross-sectional view of the intermediate member taken along line IIIb-IIIb in FIG. 3 (a), and (c) is an intermediate member according to the second embodiment. It is a side view, (d) is a sectional view of the intermediate member in line IIId-IIId in FIG. 3 (c), (e) is a side view of the intermediate member in the third embodiment, (f) These are sectional drawings of the intermediate member in the IIIf-IIIf line of Drawing 3 (e). (A) is a side view of the intermediate member in 4th Embodiment, (b) is sectional drawing of the intermediate member in the IVb-IVb line | wire of Fig.4 (a), (c) is 5th implementation. It is a side view of the intermediate member in a form, (d) is a sectional view of the intermediate member in the IVd-IVd line of Drawing 4 (c), (e) is a side view of the intermediate member in a 6th embodiment. FIG. 4F is a cross-sectional view of the intermediate member taken along line IVf-IVf in FIG.

  Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a front view of a cutting tool 10 according to a first embodiment of the present invention. As shown in FIG. 1, the cutting tool 10 is formed of a carbon steel material having a carbon content of 0.1 to 1.4 wt% and a shank member 20 having a shank portion 21 and a cemented carbide. A cutting blade member 30 having a cutting edge 31 and an intermediate member 40 connecting the shank member 20 and the cutting blade member 30 are mainly provided. The shank member 20 is not limited to a carbon steel material, and may be structural steel, alloy tool steel, or cold die steel.

  The cutting blade member 30 is mainly composed of WC, the Co content is set to 5 wt% or more and 16 wt% or less, and the hardness as a material before performing friction welding described later is 89 HRA or more and 95 HRA or less. Is set. Thereby, the cutting performance can be improved. HRA means A-scale Rockwell hardness using a diamond conical material defined in JIS-Z2245 as an indenter, and cutting performance means sharpness, durability, wearability, and the like.

  The intermediate member 40 is formed of a Co—Ni—Fe alloy, and at least the Co content is set to 5 wt% or more and 40 wt% or less, and the Ni content is set to 20 wt% or more and 50 wt% or less.

  Here, the cemented carbide is likely to crack when subjected to a tensile residual stress. On the other hand, since the steel material is a metal and rich in ductility, the steel material can be deformed in a mode of relaxing residual stress. Therefore, the cutting blade member 30 can be prevented from being damaged by approximating the thermal expansion coefficient of the intermediate member 40 to the thermal expansion coefficient of the cutting blade member 30.

  In this embodiment, the thermal expansion coefficient of the cutting blade member 30 is about 6 to 6.5, and the thermal expansion coefficient of the shank member 20 is about 12. The intermediate member 40 has substantially the same thermal expansion coefficient as that of the cutting blade member 30 in a state where the frictional heat is generated and the temperature is relatively high (about 500 degrees) (see FIGS. 2B and 2C). Become. Therefore, it is possible to prevent cracks from occurring in the cutting blade member 30 due to residual stress and to ensure the deformability when pressed in the axial direction. As a result, sufficient bonding strength can be ensured. In addition, the composition ratio of the member 30 for cutting blades and the intermediate member 40 is an example, and can be changed suitably.

  In the present embodiment, the shank member 20 and the cutting blade member 30 are each formed from a round bar having a diameter of 16 mm. The intermediate member 40 is formed of a disk member having a diameter of 16 mm and a thickness of 10 mm before compression. Note that the end surfaces of the shank member 20, the cutting blade member 30, and the intermediate member 40 that are in contact with each other are formed so as to expand perpendicular to the axial direction.

  Then, with reference to FIG. 2, the manufacturing method of the cutting tool 10 (refer FIG. 1) is demonstrated. The manufacturing method of the cutting tool 10 mainly includes a forming process, a fitting process, a contact process, and a joining process. Each step will be described later in order.

  2 (a) to 2 (c) are front views of the friction welding mechanism 1 illustrating the manner in which the shank member 20, the cutting blade member 30, and the intermediate member 40 are joined by friction welding in time series. FIG. 2D is a front view of the joined shank member 20, cutting blade member 30 and intermediate member 40. 2 (a) and 2 (c), each member is partially viewed in cross section, and FIG. 2 (d) illustrates a state after removing burrs generated by friction welding.

  As shown in FIGS. 2 (a) to 2 (c), the friction welding mechanism 1 includes a rotary shaft 2 formed so as to be axially rotatable, and a rotary gripping device (collet chuck) attached to the tip of the rotary shaft 2. 3, a clamp table 4 disposed opposite to the rotary gripping device 3, and a non-rotating gripping device (vise) 5 disposed on the clamp table 4 with the same axis as the rotary gripping device 3. Configured. The non-rotating gripping device 5 is viewed in cross section. Here, the shape of the intermediate member 40 is demonstrated with reference to Fig.3 (a) and FIG.3 (b).

  3A is a side view of the intermediate member 40, and FIG. 3B is a cross-sectional view of the intermediate member 40 taken along the line IIIb-IIIb in FIG. 3A. In the forming step, the intermediate member 40 is fitted to the first end surface 41 which is the end surface on the side to be joined to the shank member 20 (see FIG. 2), which is a circular recess having a diameter of 10 mm and a depth of 3 mm. A recess 43 is formed coaxially with the intermediate member 40.

  Returning to FIG. In the forming step, the shank member 20 has a fitting convex portion 23 having a shape obtained by inverting the fitting concave portion 43 of the intermediate member 40 and the concavity and convexity on the connecting end surface 22 which is the end surface to be joined to the intermediate member 40. Are formed symmetrically with respect to the shank member 20 (see FIG. 2A). In this embodiment, the to-be-fitted convex part 23 is formed in a cylindrical shape whose diameter is slightly larger than the diameter (10 mm) of the fitting concave part and having a height of 3 mm.

  Here, as the intermediate member 40 is formed thinner, the joint strength of friction welding is improved. In the present embodiment, since the overhanging portion of the mating convex portion 23 is closest to the flat end surface 32 of the cutting blade member 30, the diameters of the mating convex portion 23 and the mating concave portion 43 are the shank member 20 and As the outer diameter of the intermediate member 40 is larger, the bonding strength is improved. Therefore, the diameters of the fitted convex portion 23 and the fitting concave portion 43 are preferably 50% or more of the outer diameter of the intermediate member 40, and more preferably 60% or more of the outer diameter of the intermediate member 40. The length is preferably set (in the present embodiment, it is set to about 63%).

  As described above, since the diameter of the fitted convex portion 23 is formed to be slightly larger than the diameter of the fitted concave portion 43, the fitting step of fitting the fitted convex portion 23 and the fitted concave portion 43 together. The intermediate member 40 can be press-fitted and fixed to the shank member 20. Thereby, the intermediate member 40 and the shank member 20 can be integrated and conveyed. Further, it is possible to easily attach the shank member 20 and the intermediate member 40 to the rotary gripping device 3, and the intermediate member 40 is displaced in the axis-perpendicular direction with respect to the shank member 20 during the friction welding. Can be suppressed.

  In the present embodiment, the term “fitting” means that there are locations where the shank member 20 and the intermediate member 40 are in contact with each other when the shank member 20 and the intermediate member 40 are in contact with each other when moving relative to each other in the direction perpendicular to the axis. The same applies to the following embodiments. For example, if the fitting is performed by press-fitting (shrink fit), the shank member 20 and the intermediate member 40 can be conveyed integrally. For example, if the fitting is performed by clearance fit, the shank member 20 is effective. And the intermediate member 40 can be easily integrated without using a special tool, so that the work of the fitting process can be facilitated. For example, in the case of knurling, the contact area is increased. This has the effect of ensuring the transmission of the driving force.

  A friction welding procedure including the contact step and the joining step will be described. As shown in FIG. 2A, the cutting blade member 30 is fixed to the non-rotating gripping device 5. Moreover, the member 20 for shank is the state on the opposite side of the edge part in which the to-be-fitted convex part 23 is formed in the state by which the to-be-fitted convex part 23 was fitted by the press-fit fixation to the fitting recessed part 43 of the intermediate member 40. The end is gripped by the rotary gripping device 3.

  Thereby, when the intermediate member 40 is interposed and the shank member 20 and the cutting blade member 30 are friction welded, the intermediate member 40 and the shank member 20 can be coupled by fitting.

  In the present embodiment, since the shaft is naturally aligned by fitting the intermediate member 40 to the shank member 20, conventionally, between the device for gripping the shank member 20 and the device for gripping the intermediate member 40. The axial alignment process of the intermediate member 40 which has been performed can be omitted. Furthermore, the cutting process of the intermediate member 40 conventionally required can be omitted.

  That is, when the friction welding is performed in two steps as in the prior art, the intermediate member 40 needs to be gripped by the rotary gripping device 3 or the non-rotary gripping device 5, and the intermediate member 40 needs a grip allowance. Therefore, a process of cutting the intermediate member 40 between the first stage friction welding and the second stage friction welding is necessary. On the other hand, in the friction welding in the present embodiment, the intermediate member 40 does not require a grip margin, and the intermediate member 40 can be shortened from the beginning, so that the cutting step of the intermediate member 40 can be omitted.

  As shown in FIG. 2B, in the contact step in which the intermediate member 40 and the cutting blade member 30 are contacted, the rotating shaft 2 is rotated to rotate and rotate the shank member 20 and the intermediate member 40. The gripping device 3 is slid to the clamp base 4 side. Frictional heat is generated by concentrically pressing the second end surface 42 opposite to the first end surface 41 of the intermediate member 40 against the flat end surface 32 of the cutting blade member 30 with the thrust P1. At this time, the cutting blade member 30 and the intermediate member 40 are rotated in a state of being in full contact. Further, since the intermediate member 40 is press-fitted and fixed to the shank member 20, the driving force generated when the rotating shaft 2 is rotated is transmitted to the intermediate member 40.

  As shown in FIG. 2C, in the joining process for joining the shank member 20, the cutting blade member 30, and the intermediate member 40, frictional heat generated between the cutting blade member 30 and the intermediate member 40 is used. When the second end portion 42 of the intermediate member 40 is sufficiently softened and goes around the cutting blade member 30, the rotation of the rotary shaft 2 is suddenly stopped, and the thrust in the axial direction of the rotary shaft 2 is increased. Next pressurization (upset pressurization) is performed. In the present embodiment, the intermediate member 40 is strongly pressed against the cutting blade member 30 with a thrust P2 (P2> P1). As a result, the intermediate member 40 is sufficiently plastically deformed to join the shank member 20 and the cutting blade member 30 together.

  The joining of the shank member 20 and the intermediate member 40 in the joining process will be described. Since the shank member 20 and the intermediate member 40 are fixed so as not to rotate relative to each other by press-fitting, no frictional heat is generated on the contact surfaces of the shank member 20 and the intermediate member 40. On the other hand, as described above, frictional heat is generated on the contact surface between the flat end surface 32 of the cutting blade member 30 and the intermediate member 40, and the frictional heat is contacted between the intermediate member 40 and the shank member 20. It is transmitted to the surface by heat conduction. Thereby, since the location contact | abutted to the connection end surface 22 of the intermediate member 40 is fully softened, the member 20 for shank and the intermediate member 40 are joined by the secondary pressurization mentioned above.

  As described above, since the pair of contact surfaces can be welded by a single pressurization, the intermediate member 40 has the shank member 20 and the intermediate member 40 in comparison with the conventional method of friction welding after the intermediate member 40 is altered. It can sufficiently wrap around the cutting blade member 30 and can be uniformly joined. Therefore, the occurrence of poor welding can be suppressed.

  In this embodiment, from the state in which the cutting blade member 30 and the intermediate member 40 are in contact with each other until the joining of the cutting blade member 30 and the intermediate member 40 is completed (see FIG. 2C), the clamp base 4 Is moved toward the rotation holding device 3 (that is, the compression amount of the intermediate member 40) is set to about 6 mm. In the present embodiment, the upset amount (compression amount at the time of upset pressurization) ≈6 mm. Accordingly, the thickness t of the intermediate member 40 after the joining of the cutting blade member 30 and the intermediate member 40 is completed is 1 mm (= (thickness of the disc 10 mm) − (depth of the fitting recess 43 3 mm)) − (intermediate) Since the compression amount of the member 40 is 6 mm)), sufficient bonding strength can be exhibited.

  Here, for example, when the intermediate member 40 is decentered in the axis-perpendicular direction with respect to the shank member 20, the intermediate member 40 may not be uniformly compressed. That is, the compressive force applied to the intermediate member 40 becomes non-uniform due to the displacement of the axis in the compression direction, and the force applied to the shank member 20 and the cutting blade member 30 as a reaction from the intermediate member 40 is used for the shank. The member 20 and the cutting blade member 30 may be relatively inclined. In this case, the shank member 20 and the cutting blade member 30 may directly contact each other. On the other hand, in this embodiment, since the intermediate member 40 can be prevented from being eccentric with respect to the shank member 20, the compression amount (upset amount) of the intermediate member 40 is uniform over the entire range of the contact surface. And the amount of compression can be stabilized.

  As shown in FIG. 2 (d), after the secondary pressurization, when the joining is completed, low-temperature slow cooling is performed in the furnace, and the generated burrs are cut to produce a cutting tool material. The cutting tool 10 (refer FIG. 1) is completed by forming the cutting edge 31 in the cutting tool raw material shown in FIG.2 (d).

  In order to compare the bonding strength of the cutting tool 10 according to this embodiment with respect to a test piece by diffusion bonding and a test piece by brazing bonding, the bonding strength was measured. Note that the shank member 20, the cutting blade member 30, and the intermediate member 40 having the same composition as in the present embodiment are used for the diffusion bonding test piece, and are pressed with the thrust P2 described above. The member 40 was not used, but the shank member 20 and the cutting blade member 30 having the same composition as the present embodiment were used. As a result, the cutting tool 10 according to the present embodiment has a bonding strength that is 155% higher than that of the test piece obtained by brazing joining, and a substantially equivalent joining strength is recognized for the test piece obtained by diffusion bonding.

  In addition, with respect to the processing time including end face processing, setup at the time of joining, and joining processing time, the cutting tool material in this embodiment takes about 10 minutes to join, and the specimen for diffusion joining takes about 10 minutes to join. It took 26 minutes. That is, the production efficiency of the cutting tool material of this embodiment is improved by 260% compared to the diffusion bonding test piece.

  Next, the intermediate member 240 in the second embodiment will be described with reference to FIGS. 3C and 3D. In the first embodiment, the case where the intermediate member 40 is press-fitted and fixed to the shank member 20 has been described. However, the intermediate member 240 in the second embodiment is temporarily held by the shank member 20 and can be relatively rotated. The In addition, the same code | symbol is attached | subjected to the part same as 1st Embodiment mentioned above, and the description is abbreviate | omitted.

  FIG. 3C is a side view of the intermediate member 240 in the second embodiment, and FIG. 3D is a cross-sectional view of the intermediate member 240 taken along line IIId-IIId in FIG. In addition, the member for shank (not shown) in this embodiment differs only in the shape of the member 20 for shank (refer FIG. 1) in 1st Embodiment, and the connection end surface 22 (refer FIG. 2 (a)). Specifically, the fitted convex portion 23 (see FIG. 2A) is not formed, but the fitted concave portion 243 of the intermediate member 240 and the fitted convex portion (not shown) having an inverted shape are formed. Is done.

  As shown in FIGS. 3C and 3D, the intermediate member 240 includes a recess having a circular cross section and a fitting recess 243 formed coaxially with the recess. Here, the fitting concave portion 43 in the first embodiment is merely brought into contact with the fitting convex portion 23 from the radially inner side. On the other hand, the fitting recess 243 in the present embodiment is a recess having a circular cross section and is brought into contact with the fitting convex portion from the inside in the radial direction. It is contacted from. Therefore, the frictional force generated between the shank member and the fitting recess 243 can be improved, and the intermediate member 240 can be prevented from falling off from the shank member.

  The fitting recess 243 is formed with a dimensional tolerance of a clearance fit with respect to the fitting protrusion of the shank member. Therefore, the intermediate member 240 and the shank member can be relatively rotated in the contact step and the joining step (see FIG. 2C).

  When the intermediate member 240 rotates relative to the shank member, the contact surface between the intermediate member 240 and the shank member or the contact surface between the intermediate member 240 and the cutting blade member 30 (see FIG. 1). Frictional heat is generated on at least one of the contact surfaces. The frictional heat is transmitted to the other abutting surface by heat conduction, whereby both of the abutting surfaces are softened together, and the shank member, the cutting blade member 30 and the intermediate member 40 are subjected to the secondary pressure described above. Are joined.

  Next, the intermediate member 340 in the third embodiment will be described with reference to FIGS. 3 (e) and 3 (f). In the first embodiment, the case where the fitting concave portion 43 is formed on the first end surface 41 of the intermediate member 40 has been described. However, in the intermediate member 340 according to the third embodiment, the fitting convex portion 343 is formed on the first end surface 41. Is done. In addition, the same code | symbol is attached | subjected to the part same as each embodiment mentioned above, and the description is abbreviate | omitted.

  FIG.3 (e) is a side view of the intermediate member 340 in 3rd Embodiment, FIG.3 (f) is sectional drawing of the intermediate member 340 in the IIIf-IIIf line | wire of FIG.3 (e). In addition, the member for shank (not shown) in this embodiment differs only in the shape of the member 20 for shank (refer FIG. 1) in 1st Embodiment, and the connection end surface 22 (refer FIG. 2 (a)). In detail, the fitting convex part 23 (refer FIG. 2A) is not formed, but the fitting concave part (not shown) formed from the shape which reversed the fitting convex part 343 of the intermediate member 340 and the unevenness | corrugation. ) Is formed.

  In the region where the shank member and the cutting blade member 30 are closest to each other, that is, the region excluding the fitting convex portion 343 of the first end surface 41 of the intermediate member 340, the bonding strength between the shank member and the cutting blade member 30 is assumed. Therefore, the diameter of the fitting convex portion 343 is preferably set to 40% or less of the diameter of the intermediate member 340, and more preferably set to 25% or less of the diameter of the intermediate member 340. preferable. In this embodiment, since the diameter of the fitting convex part 343 is set to 4 mm (25% of the diameter of the intermediate member 340), sufficient bonding strength can be ensured.

  Next, the intermediate member 440 in the fourth embodiment will be described with reference to FIGS. 4 (a) and 4 (b). In the first embodiment, the case has been described in which the fitting recess 43 is formed on the first end surface 41 of the intermediate member 40 in an axisymmetric manner. However, the intermediate member 440 in the fourth embodiment has a pair of fittings on the first end surface 41. A convex portion 443 is formed away from the shaft. In addition, the same code | symbol is attached | subjected to the part same as each embodiment mentioned above, and the description is abbreviate | omitted.

  FIG. 4A is a side view of the intermediate member 440 in the fourth embodiment, and FIG. 4B is a cross-sectional view of the intermediate member 440 taken along the line IVb-IVb in FIG. In addition, the member for shank (not shown) in this embodiment differs only in the shape of the member 20 for shank (refer FIG. 1) in 1st Embodiment, and the connection end surface 22 (refer FIG. 2 (a)). Specifically, the fitted convex portion 23 (see FIG. 2A) is not formed, but the fitted convex portion 443 of the intermediate member 440 and the fitted concave portion (not shown) having a shape obtained by inverting the concave and convex portions. It is formed.

  Since the pair of fitting projections 443 are formed away from the axis of the intermediate member 440, when the intermediate member 440 and the shank member are fitted, the relative rotation between the intermediate member 440 and the shank member is mechanical. Is prevented. Therefore, even if the intermediate member 440 is not press-fitted and fixed to the shank member, the driving force generated when the rotating shaft 2 is rotated can be reliably transmitted to the intermediate member 440.

  Next, the intermediate member 540 in the fifth embodiment will be described with reference to FIGS. 4C and 4D. In the first embodiment, the case where the fitting recess 43 having a circular cross section is formed on the first end surface 41 of the intermediate member 40 has been described. However, the intermediate member 540 in the fifth embodiment has a polygonal cross section on the first end surface 41. A fitting recess 543 is formed which is a depression (regular octagonal shape in this embodiment). In addition, the same code | symbol is attached | subjected to the part same as each embodiment mentioned above, and the description is abbreviate | omitted.

  FIG. 4C is a side view of the intermediate member 540 in the fifth embodiment, and FIG. 4D is a cross-sectional view of the intermediate member 540 taken along line IVd-IVd in FIG. In addition, the member for shank (not shown) in this embodiment differs only in the shape of the member 20 for shank (refer FIG. 1) in 1st Embodiment, and the connection end surface 22 (refer FIG. 2 (a)). Specifically, the fitted convex portion 23 (see FIG. 2A) is not formed, but the fitted concave portion 543 of the intermediate member 540 and the fitted convex portion (not shown) having an inverted shape are formed. Is done.

  Relative rotation is prevented by the inner surface of the fitting recess 543 of the intermediate member 540 coming into contact with the outer surface of the fitting projection of the shank member in the rotational direction. As a result, the driving force generated by rotating the rotating shaft 2 can be reliably transmitted to the intermediate member 540.

  Next, the intermediate member 640 in the sixth embodiment will be described with reference to FIGS. 4 (e) and 4 (f). In the first embodiment, the case where the fitting recess 43 having a circular cross section is formed on the first end surface 41 of the intermediate member 40 has been described. However, the intermediate member 640 in the sixth embodiment is formed by knurling the first end surface 41. A fitting recess 643 is formed. In addition, the same code | symbol is attached | subjected to the part same as each embodiment mentioned above, and the description is abbreviate | omitted.

  FIG. 4E is a side view of the intermediate member 640 in the sixth embodiment, and FIG. 4F is a cross-sectional view of the intermediate member 640 taken along line IVf-IVf in FIG. In addition, the member for shank (not shown) in this embodiment differs only in the shape of the member 20 for shank (refer FIG. 1) in 1st Embodiment, and the connection end surface 22 (refer FIG. 2 (a)). Specifically, the fitted convex portion 23 (see FIG. 2A) is not formed, and a flat surface is formed on the end surface of the shank member (not shown) that comes into contact with the fitting concave portion 643 of the intermediate member 640. It is formed.

  In the present embodiment, the intermediate member 640 is not fitted to the shank member, and the intermediate member 640 falls at the stage of friction welding preparation (see FIG. 2A), so that the fall is prevented. Therefore, it is preferable to hold the intermediate member 640 with another jig. The end surface of the shank member may be formed with a fitting convex portion (not shown) having a shape obtained by inverting the fitting concave portion 643 and the concave and convex portions.

  In the intermediate member 640 of the present embodiment, the fitting recess 643 is formed by knurling, and cutting is not necessary, so that the intermediate member 640 can be easily processed.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and various modifications and improvements can be made without departing from the spirit of the present invention. Can be easily guessed.

  In each of the above-described embodiments, a part or all of the configuration in one embodiment may be combined with or replaced with a part or all of the configuration in the other embodiments to form another embodiment.

  In each of the above embodiments, the case where the shank member 20 and the intermediate members 40, 240, 340, 440, and 540 are fitted together has been described, but the present invention is not necessarily limited thereto. For example, the cutting blade member 30 may be processed and fitted with the intermediate members 40, 240, 340, 440, and 540.

  In each of the above embodiments, the case where the shank member 20, the cutting blade member 30, and the intermediate members 40, 240, 340, 440, 540, and 640 have the same diameter has been described, but the present invention is not necessarily limited thereto. Absent. For example, the diameter of the intermediate member 40 may be larger than that of the shank member 20 and the cutting blade member 30. As a result, even when the intermediate member 40 and the shank member 20 are slightly displaced in the direction perpendicular to the axis, the compression amount (upset amount) of the intermediate member 40 can be kept uniform.

  In each of the above embodiments, the case where the shank member 20 is rotated by rotating the rotating shaft 2 has been described, but the present invention is not necessarily limited thereto. For example, the cutting blade member 30 may be rotated, or both the shank member 20 and the cutting blade member 30 may be rotated.

  In each said embodiment, although the case where the fitting recessed parts 43,243,543,643 and the fitting convex parts 343,443 were formed in various shapes was demonstrated, it is not necessarily restricted to this. For example, the fitting concave portions 43, 243, 543, 643 and the fitting convex portions 343, 443 may be formed in a cross shape, a rectangular shape, a conical shape, a polygonal pyramid shape, and a shape in which unevenness is mixed.

  In each of the above embodiments, the dimensional relationship between the intermediate members 40, 240, 340, 440, 540 and the shank member 20 is defined by press fitting, clearance fitting, or the like, but this is not necessarily limited thereto. For example, the intermediate member 40 of the embodiment (for example, the first embodiment) that is specified to be press-fitted and fixed may be fitted to the shank member 20 by clearance fit, or it is specified that the intermediate member 40 is fitted by clearance fit. The intermediate member 240 of the embodiment (for example, the second embodiment) may be press-fitted and fixed to the shank member.

  In the fourth embodiment, the case where the pair of fitting convex portions 443 are formed apart from the shaft has been described. However, the present invention is not necessarily limited thereto. For example, three or four fitting protrusions 443 may be formed, and one of the fitting protrusions 443 may be formed on the axis of the intermediate member 440. In addition, it is preferable that the fitting convex part 443 formed away from the shaft is formed at equal intervals in the circumferential direction in order to evenly distribute the force received by the fitting convex part 443 in the rotation direction.

  In the fifth embodiment, the case where the fitting recess 543 is a depression having a regular octagonal cross section has been described. However, the present invention is not necessarily limited thereto. For example, a depression such as a triangle or a rectangle may be used, or a star-shaped depression may be used.

10 Cutting tool 20 Shank member (second member)
21 Shank part 23 Fitting convex part (fitting part)
30 Cutting blade member (first member)
31 Cutting edge 32 Flat end face (Axial end face)
40 Intermediate member 42 Second end face (end face in the axial direction)
43, 243, 543, 643 Fitting recess (fitting part)
343,443 Fitting convex part (fitting part)

Claims (7)

A first member made of cemented carbide and having a cutting edge; a second member made of steel and having a shank portion; and an intermediate member interposed between axial end surfaces of the first member and the second member. In the provided cutting tool,
The intermediate member includes a fitting portion formed on an axial end surface, and one of the first member and the second member is formed on the axial end surface so as to be fitted to the fitting portion of the intermediate member. Provided with a fitted portion,
The fitting portion of the intermediate member and the fitted portion of one of the first member and the second member are fitted, and the intermediate member on the side opposite to the side on which the fitting portion is formed. With the axial end surface of the other of the first member and the second member in contact with the axial end surface, the first member and the second member are pressed in the axial direction after being relatively rotated about the axis. Thus, the cutting tool, wherein the first member and the intermediate member are joined and the intermediate member and the second member are joined. A first member made of cemented carbide and having a cutting edge; a second member made of steel and having a shank portion; and an intermediate member interposed between axial end surfaces of the first member and the second member. In the manufacturing method of the provided cutting tool,
A fitting portion is formed on the axial end surface of the intermediate member, and a fitted portion that can be fitted to the fitting portion of the intermediate member on one axial end surface of the first member or the second member. Forming process to form;
A fitting step of fitting a fitting portion in the intermediate member formed by the forming step and a fitted portion in one of the first member and the second member;
After the fitting process, the fitted portion in one of the first member and the second member and the fitting portion in the intermediate member are fitted, and then the fitting portion of the intermediate member is formed. An abutting step of abutting an axial end surface opposite to the first side and an axial end surface of the other of the first member and the second member;
A state in which the axial end surface of the intermediate member opposite to the side on which the fitting portion is formed is brought into contact with the other axial end surface of the first member or the second member by the contact step. Then, the first member and the second member are rotated relative to each other around the axis, and then pressed in the axial direction, thereby joining the first member and the intermediate member and joining the intermediate member and the second member. And a cutting tool manufacturing method comprising: a step.   The fitting portion is formed as a cylindrical convex portion coaxial with the intermediate member, and the fitted portion is coaxial with one of the first member or the second member and outside the convex portion. A recess having a circular cross section having an inner diameter smaller than the diameter, or the fitting portion being formed as a circular recess having a circular cross section coaxial with the intermediate member, and the fitted portion being the first member or the first 3. The cutting tool according to claim 1, wherein the cutting tool is formed as a cylindrical convex portion that is coaxial with one of the two members and has an outer shape larger than an inner diameter of the concave portion. Production method.   The method for manufacturing a cutting tool or a cutting tool according to claim 3, wherein the fitting portion is formed as a concave portion, and the fitted portion is formed as a convex portion.   The said fitting part is formed in the said 2nd member, The manufacturing method of the cutting tool or cutting tool in any one of Claim 1 to 4 characterized by the above-mentioned.   The cemented carbide is mainly composed of WC, the Co content is set to 5 wt% or more and 16 wt% or less, and the hardness is set to 89 HRA or more and 95 HRA or less. 6. The cutting tool according to any one of 5 or a method for producing a cutting tool. The intermediate member is formed of a Co-Ni-Fe alloy, and at least the Co content is set to 5 wt% to 40 wt%, and the Ni content is set to 20 wt% to 50 wt%. The manufacturing method of the cutting tool or cutting tool of Claim 6.

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