JP5594210B2 - Manufacturing method of head exchangeable cutting tool, and connecting member used in the manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a head exchangeable cutting tool such as a cutting head having a blade portion or a holder for holding the cutting head, and a connecting member used in the manufacturing method for connecting the cutting head and the holder. It is about.

  As such a head replaceable cutting tool, for example, in Patent Document 1, a male screw portion is formed at the rear end portion of a cutting head integrally formed of cemented carbide, and this male screw portion is formed into a female screw portion formed in a holder. It has been proposed to be screwed into the connection. Moreover, in patent document 2, a steel part is fixed to the shank part which consists of a cemented carbide by brazing, and the internal thread part for fixing a cutting head in the back | inner side rather than the side by which the cutting head of this steel part is mounted | worn. The one formed is proposed.

Japanese Patent Laid-Open No. 7-164234 JP 2003-251540 A

  However, if the male screw part is directly formed on a cutting head made of a cemented carbide which is a hard and brittle material as in the head exchangeable cutting tool described in Patent Document 1, the thread is not chipped. It tends to occur and cannot be reliably connected to the holder. Moreover, in the holder which fixed the shank part which consists of a cemented carbide alloy and the steel part in which the internal thread part was formed like patent document 2 by brazing, ensuring the intensity | strength of the junction part of these shank parts and a steel part. Is difficult, and the steel part may be detached from the shank part by cutting resistance.

  Accordingly, the inventors of the present invention previously described in Japanese Patent Application Nos. 2010-272765 and 2010-218643 to a tool body made of a hard material such as a cemented carbide of a head exchangeable cutting tool such as a cutting head or a holder. An attachment hole having a concave portion such as an uneven surface with a predetermined surface roughness on the inner peripheral surface is formed, and a cylindrical attachment portion of a connecting member made of a metal material having a hardness lower than that of the hard material is formed in the attachment hole. Is inserted into the inner peripheral portion of the mounting portion, and a press-fitting member having an outer diameter larger than the inner diameter of the mounting portion is press-fitted to be plastically deformed to expand the mounting portion, and the outer peripheral surface of the mounting portion is attached. It proposes joining these tool main bodies and a connection member by making it closely_contact | adhere to the internal peripheral surface of a hole and engaging with the said recessed part.

  Therefore, in such a head replaceable cutting tool, the cutting head and the screw portion for connecting the holder are formed on the connecting member made of the metal material which is low in hardness but high in toughness and hardly chipped. And the holder can be reliably connected. In addition, the mounting portion is plastically deformed so as to be expanded in diameter by the press-fitting member, and the outer peripheral surface thereof is in close contact with the inner peripheral surface of the mounting hole and is engaged with the concave portion. The strength is high, and the cutting head does not fall off due to the cutting force detaching the tool body and the connecting member.

  By the way, when the tool body of the cutting head or the holder is formed of a powder sintered material such as a cemented carbide as described above, significant shrinkage occurs when the powder material formed by press molding or the like is sintered. The shrinkage rate varies depending on the sintered state, and when the concave portion formed on the inner peripheral surface of the mounting hole is an uneven surface as described above, the inner peripheral surface is left as an unpolished sintered skin. It is inevitable that a certain amount of error occurs in the inner diameter of the mounting hole in the subsequent tool body. However, on the other hand, as described above, when the attachment portion of the connecting member is plastically deformed to expand the diameter, the clearance from the inner peripheral surface of the attachment hole is too large. If the clearance is too small, an excessive tensile stress acts on the tool body to cause cracks.

  For this reason, a plurality of types of connecting members having different outer diameters of the mounting portions are prepared, the inner diameter dimensions of the mounting holes in the sintered tool body one by one, and pin gauges having different outer diameters in order as mounting holes. A connecting member having an outer diameter mounting portion that is measured by insertion and has an optimum clearance must be selected and joined to the tool body. Therefore, not only multiple types of pin gauges are required, but also a connecting member corresponding to the measurement result of the pin gauge must be selected from a plurality of types of connecting members and inserted into the mounting hole of the tool body. Therefore, the work becomes complicated.

  In addition, if there is a clearance between the mounting portion in the state where the mounting portion is inserted into the mounting hole in this way, the mounting portion may be inserted with an inclination or eccentricity with respect to the mounting hole within this clearance range. There is. Then, when the press-fitting member is press-fitted in a state where the mounting portion is inclined or eccentric and the mounting portion is plastically deformed, the outer peripheral surface of the mounting portion is brought into close contact with the inner peripheral surface of the mounting hole as it is, and the concave portion and There is also a possibility that the tool body and the connecting member are joined in a state of being tilted or eccentric.

  The present invention has been made under such a background, and improves workability when joining the tool body and the connecting member, and reliably joins the tool body and the connecting member coaxially. It is an object of the present invention to provide a method for manufacturing a head exchangeable cutting tool capable of performing the above and a connecting member used in the manufacturing method.

  In order to solve the above-described problems and achieve such an object, a method for manufacturing a head-exchangeable cutting tool according to the present invention includes a mounting hole having a recess on an inner peripheral surface formed on a tool body made of a hard material. The cylindrical mounting portion of the connecting member made of a metal material whose hardness is lower than that of the hard material is inserted, and a part of the mounting portion in the center line direction of the cylinder formed by the mounting portion is used as the diameter expanding portion. The head-replaceable cutting tool that joins the tool body and the connecting member by plastically deforming so that the outer peripheral surface of the enlarged diameter portion is brought into close contact with the inner peripheral surface of the mounting hole and is engaged with the recess. In the manufacturing method, the remaining portion excluding the enlarged diameter portion of the attachment portion of the connecting member has an outer diameter larger than the enlarged diameter portion and capable of sliding contact with the inner peripheral surface of the attachment hole. A step is formed, and the step is brought into sliding contact with the mounting portion to the mounting hole. In terms of the input, and wherein the plastically deforming the enlarged diameter portion.

  Further, the connecting member of the present invention is a connecting member used in such a method for manufacturing a head exchangeable cutting tool, and has a cylindrical mounting portion. The outer diameter step portion having a larger diameter than the enlarged diameter portion and capable of sliding contact with the mounting hole of the tool body is formed in the remaining portion excluding the enlarged diameter portion. It is characterized by.

  In the manufacturing method of such a head replaceable cutting tool and the connecting member used in the manufacturing method, the remaining portion excluding the expanded portion that is expanded by plastic deformation of the mounting portion of the connecting member, that is, plasticity A step portion that is larger in diameter than the above-mentioned enlarged diameter portion and that can be slidably contacted with a mounting hole of a cutting head or a holder that is used as a tool main body of the head exchangeable cutting tool is formed in the portion that cannot be deformed. By preparing multiple types of connecting members with different outer diameters and a constant difference in outer diameter with the enlarged diameter part, the tool body can be mounted using the connecting members themselves without the need for pin gauges, etc. The inner diameter of the hole can be confirmed.

  That is, the outer diameter of the enlarged diameter portion is set so that the difference in outer diameter with the stepped portion is equal to the predetermined clearance with the mounting hole, and the above-described multiple types of connecting members are attached in the order of, for example, the smallest outer diameter. When it is inserted into the hole and the stepped part is caught in the mounting hole and cannot be inserted, the outer diameter of the mounting part of the previous connecting member can be judged to have the optimum clearance from the mounting hole. it can. Therefore, if the diameter-enlarged portion is plastically deformed and expanded by reinserting the previous connecting member into the attachment hole and press-fitting the press-fit member into the inner peripheral portion of the attachment portion, the tool body will crack. It is possible to reliably join the connecting members with sufficient strength without causing any problems.

  Further, if the outer peripheral surface of the stepped portion, the outer peripheral surface of the enlarged diameter portion to be plastically deformed, and the inner peripheral portion of the cylindrical mounting portion are formed coaxially, the stepped portion can be brought into sliding contact with the mounting hole. Thus, the mounting portion is positioned coaxially with the mounting hole. Accordingly, the diameter-enlarged portion of the mounting portion that is brought into close contact with the mounting hole and engaged with the concave portion is not inclined or decentered, and the mounting portion is evenly and uniformly distributed over the entire circumference. Can be joined.

  Here, in order to expand only the diameter-expanded portion without plastically deforming the stepped portion in the mounting portion, one step is to form the stepped portion on the front side in the insertion direction of the mounting portion into the mounting hole. After the stepped portion is brought into sliding contact, the mounting portion is inserted into the mounting hole, and a press-fitting member having an outer diameter larger than the inner diameter of the mounting portion in the enlarged diameter portion is pressed into the inner periphery of the mounting portion in the insertion direction. And stop before the step.

  In this case, since the press-fitting member is stopped before the stepped portion, the stepped portion slidably in contact with the mounting hole does not expand and the tool body is not cracked. In addition, since the stepped portion is formed on the distal end side in the insertion direction of the mounting portion, the connecting member whose outer diameter of the stepped portion is larger than the inner diameter of the mounting hole can be hooked from the beginning to insert the mounting portion into the mounting hole. The optimum clearance can be quickly confirmed.

  As another one, the step portion is formed on the rear side in the insertion direction of the attachment portion into the attachment hole, and the inner diameter of the attachment portion in the step portion is larger than the inner diameter of the attachment portion in the enlarged diameter portion. Then, after the step portion is brought into sliding contact, the attachment portion is inserted into the attachment hole, and the press-fitting member has an outer diameter larger than the inner diameter of the attachment portion in the enlarged diameter portion and smaller than the inner diameter of the attachment portion in the step portion. The diameter-enlarged portion may be plastically deformed by press-fitting into the inner periphery of the mounting portion in the insertion direction.

  Also in this case, since the inner diameter of the attachment portion at the position of the step portion is larger than the outer diameter of the press-fitting member that plastically deforms the above-mentioned enlarged diameter portion of the attachment portion, the step portion is plastically deformed to expand the diameter. There is nothing. Also, the stepped portion is slidably contacted with the mounting hole on the rear side in the insertion direction of the mounting hole, that is, on the opening side to position the mounting portion, and the press-fitting member is press-fitted from the opening side to expand the diameter-expanding portion. Therefore, the inclination of the mounting portion can be prevented more reliably.

  The tool body may be a head body of a cutting head of a head-exchangeable cutting tool in which a cutting edge portion is formed at a front end portion and the mounting hole is formed at a rear end portion. It may be a holder body of a holder of a head exchangeable cutting tool in which the mounting hole is formed and the rear end portion is a shank portion. Of course, both the cutting head and the holder may be manufactured by the above manufacturing method, and the connecting member may be joined.

  However, when these cutting head and holder connecting members are connected by screwing the male and female screw parts, the tool main body is shorter than the holder main body when the tool main body is the head main body of the cutting head. It is difficult to form the female thread portion while ensuring the necessary joining length. Accordingly, it is desirable that the connecting member to be joined to the head body of the cutting head is formed with a male screw portion on the rear end side of the mounting portion, and conversely, the inner circumference of the connecting member to be joined to the holder body of the holder. It is desirable that the female threaded portion is formed on the surface after the expanded diameter portion is plastically deformed so that the coaxiality between the female threaded portion and the holder body can be secured.

  As described above, according to the present invention, the connecting member itself is inserted into the mounting hole of the tool body with the mounting portion that is inserted with an optimum clearance and expanded in diameter without using a pin gauge or the like. This can be determined by operation, and the selection work of the connecting member is facilitated, so that the work efficiency can be improved. In addition, since the mounting portion can be reliably positioned coaxially in the mounting hole and expanded in diameter, the joining strength and mounting stability of the connecting member in the head exchangeable cutting tool after manufacture can be improved.

It is a side view of the cutting head which is a head exchange type cutting tool manufactured by the 1st and 2nd embodiment of the present invention. It is a sectional side view of the head main body which is a tool main body of embodiment shown in FIG. It is (a) side view and (b) side sectional view showing a 1st embodiment of a connecting member of the present invention. FIG. 3 is a side sectional view illustrating a first embodiment of a method for manufacturing a head replaceable cutting tool according to the present invention using the connecting member according to the first embodiment shown in FIG. 3; (B) It is a sectional side view which shows the state which joined the connection member to the tool main body. It is (a) side view and (b) side sectional view showing a 2nd embodiment of a connecting member of the present invention. FIG. 5A is a side sectional view illustrating a state in which a mounting portion is inserted, illustrating a second embodiment of the method for manufacturing a head-exchangeable cutting tool of the present invention using the connecting member of the second embodiment shown in FIG. (B) It is a sectional side view which shows the state which joined the connection member to the tool main body. It is a sectional side view of the holder main body which is the tool main body of the 3rd, 4th embodiment of this invention. It is a side view which shows 3rd Embodiment of the connection member of this invention. (A) Side sectional view of the state in which the mounting portion is inserted, explaining a third embodiment of the method for manufacturing a head replaceable cutting tool of the present invention using the connecting member of the third embodiment shown in FIG. (B) Side sectional view showing a state in which a connecting member is joined to a tool body, (c) Side sectional view showing a state in which an internal thread portion is formed in an attachment hole. It is a side view which shows 4th Embodiment of the connection member of this invention. FIG. 10 is a side cross-sectional view illustrating a fourth embodiment of the method for manufacturing a head-exchangeable cutting tool according to the present invention using the connecting member according to the fourth embodiment shown in FIG. (B) Side sectional view showing a state in which a connecting member is joined to a tool body, (c) Side sectional view showing a state in which an internal thread portion is formed in an attachment hole.

  FIGS. 1 to 4 show a first embodiment of the present invention. The first embodiment and the second embodiment to be described later refer to the present invention as a cutting head of a head exchangeable cutting tool. This is applied to the manufacturing method. This cutting head includes a head body 1 as a tool body in the present embodiment integrally formed of a hard material such as cemented carbide, cermet, ceramics, etc., and stainless steel having a hardness lower than that of the hard material forming the head body 1. It is comprised from the connection member 2 which consists of metal materials which can be plastically deformed like steel materials, such as steel and die steel.

  As shown in FIGS. 1 and 2, the head body 1 is cut in order from the front end side (the common left side in FIGS. 1 to 11) to the rear end side (the common right side in FIGS. 1 to 11). A blade portion 1A on which a blade is formed, an engagement portion 1B to which a wrench or the like is engaged when the cutting head is replaced, and an outer diameter smaller than these blade portion 1A and the engagement portion 1B. It is composed of a truncated cone-shaped tapered shaft portion 1 </ b> C centering on the center line O of the head body 1 whose diameter gradually decreases toward the rear end side. However, in the blade portion 1A, the illustration of the cutting blade is omitted, and the engagement portion 1B is also omitted in FIGS. The inclination angle formed by the outer peripheral surface of the taper shaft portion 1C with respect to the center line O is preferably within a range of 1 ° to 20 °, more preferably within a range of 1 ° to 5 °. Is in the range of 1 ° to 3 °, and in this embodiment is 2 °.

  Further, from the rear end surface of the taper shaft portion 1C toward the front end side, the center of the mounting hole 1D having a circular shape with a constant diameter is coaxial with the center line O as shown in FIG. It is formed up to the boundary between the blade portion 1A and the engaging portion 1B in the line O direction. The inner peripheral surface of the mounting hole 1D is not subjected to polishing or the like, and is left as a sintered skin when the sintered powder material such as the cemented carbide forming the head body 1 is sintered. For example, the surface roughness within the range of 5 μm to 200 μm with the maximum height roughness Rz defined in JIS B 0601: 2001 (ISO 4287: 1997) (however, the reference length is 0.8 mm, the cutoff value λs = 0. 0025 mm, λc = 0.8 mm), and the inner peripheral surface itself is a recess of the mounting hole 1D.

  As shown in FIG. 3 (a), the connecting member 2 has a substantially cylindrical mounting portion 2A centered on the center line C on the front end side and a larger diameter on the rear end side than the mounting portion 2A. The male screw portion 2B is formed coaxially, and the inner peripheral portion of the cylindrical mounting portion 2A passes through the male screw portion 2B as shown in FIG. 3 (b) and opens at the rear end surface of the connecting member 2. It has been made. However, the inner peripheral portion of the connecting member 2 is a small-diameter portion 2C having a small inner diameter at the mounting portion 2A, and a large-diameter portion 2D having a larger diameter at the male screw portion 2B. It is said that. Note that the direction of twisting of the male threaded portion 2B is opposite to the direction of rotation in the cutting process when the head exchangeable cutting tool is a turning tool such as an end mill.

  In addition, in the mounting portion 2A, a part in the center line C direction is plastically deformed to be a diameter-expanded part 3 that expands, while the remaining part excluding the diameter-expanded part 3 has the diameter-expanded part. A step portion 4 having a diameter slightly larger than the outer diameter of the portion 3 and having an outer diameter capable of sliding contact with the inner peripheral surface of the mounting hole 1D of the head body 1 is formed. Here, in this 1st Embodiment, this step part 4 is formed in the front-end | tip part which is the insertion direction side at the time of inserting the attachment part 2A in the attachment hole 1D. Further, the inner diameter of the small diameter portion 2C is constant over the entire length of the attachment portion 2A from the enlarged diameter portion 3 to the stepped portion 4.

  Accordingly, the outer diameter of the stepped portion 4 is substantially equal to the inner diameter of the mounting hole 1D, and is slightly smaller within the range of the fitting tolerance. On the other hand, the outer diameter of the enlarged diameter portion 3 excluding the stepped portion 4 is plastically deformed so that the enlarged diameter portion 3 has an outer diameter substantially equal to the outer diameter of the stepped portion 4. When the surface comes into close contact with the inner peripheral surface of the mounting hole 1D, the outer peripheral surface engages with the concave portion (uneven surface), and the connecting member 2 is securely joined to the head main body 1 and is excessively large in the head main body 1. When the mounting portion 2A is inserted into the mounting hole 1D, the diameter between the outer peripheral surface of the enlarged diameter portion 3 and the inner peripheral surface of the mounting hole 1D is, for example, 0.1 mm to 0. It is set so that an optimum clearance within a range of 5 mm is formed.

  Next, a description will be given of a first embodiment of a method for manufacturing a head exchangeable cutting tool (cutting head) according to the present invention using such a connecting member 2. First, the design inner diameter of the mounting hole 1D of the head main body 1 will be described. On the other hand, a plurality of types of connecting members having the above-described configuration, in which the outer diameter of the stepped portion 3 is slidable in contact with the mounting hole 1D having the designed inner diameter, and the outer diameter of the stepped portion 3 is slightly different from this. 2 is prepared. Here, in these connecting members 2, the outer diameter of the enlarged diameter portion 3 is set so that an optimum clearance is formed between the inner peripheral surface of the mounting hole 1 </ b> D as described above. The difference in the outer diameter of the enlarged diameter portion 3 with respect to the stepped portion 4 having an outer diameter substantially equal to the inner diameter of the hole 1D is made equal among the plurality of types of connecting members 2.

  Then, the attachment portions 2A of these connecting members 2 are inserted into the attachment holes 1D in order from the smallest outer diameter of the step portion 4, and the step portions 4 are caught by the openings of the attachment holes 1D to attach the attachment portions 2A. When the previous connecting member 2 cannot be inserted into the hole 1D, the optimum clearance as described above is formed between the inner peripheral surface of the mounting hole 1D and the outer peripheral surface of the enlarged diameter portion 3 It can be judged. Note that the attachment portion 2A may be inserted into the attachment hole 1D in order from the connection member 2 having the larger outer diameter of the stepped portion 4, but in that case, the connection member is kept until the one with the optimum clearance is inserted. Since the second step portion 4 continues to be caught in the opening portion of the mounting hole 1D, there is a possibility that the opening portion may be chipped. Therefore, it is desirable to insert from the one having the smaller outer diameter as described above.

  When the connecting member 2 that forms the optimum clearance is determined in this way, the mounting portion 2A is inserted into the mounting hole 1D and the male screw portion 2B is inserted into the taper shaft portion 1C rear end surface of the head body 1 as shown in FIG. Abut. At this time, since the step portion 4 is sized so as to be slidable into the mounting hole 1 </ b> D, the connecting member 2 is positioned so that the center line C thereof is coaxial with the center line O of the head body 1. In the state in which the mounting portion 2A is inserted in this way, the stepped portion 4 has the mounting hole 1D at the position of the large-diameter engaging portion 1B of the head body 1 in the direction of the center line O as shown in FIG. Arranged at a distance from the bottom.

  Thereafter, a press-fitting member (punch) (not shown) is press-fitted into the inner peripheral portion of the connecting member 2 from the rear end side, and the diameter-expanded portion 3 is plastically deformed to expand the diameter. The press-fitting member has a bullet-like tip, and a taper shape in which the outer diameter becomes the maximum outer diameter at the press-fitting portion following the tip, and then the outer diameter is slightly reduced toward the rear end. The maximum outer diameter of the press-fitted portion is, for example, 0.2 mm to 1.0 mm larger in diameter than the inner diameter of the small diameter portion 2C of the inner peripheral portion of the connecting member 2 and the inner diameter of the large diameter portion 2D. It is slightly smaller than.

  Therefore, when such a press-fitting member is press-fitted into the small-diameter portion 2C of the connecting member 2, the enlarged-diameter portion 3 of the mounting portion 2A is plastically deformed by the press-fitting portion and is expanded to the outer peripheral side. The outer peripheral surface of 3 is closely attached to the inner peripheral surface of the mounting hole 1D, and the outer peripheral surface of the enlarged diameter portion 3 is deformed so as to follow the concave portion (uneven surface) formed on the inner peripheral surface, and bites into the concave portion. As shown in FIG. 4B, the connecting member 2 is joined to the cutting head 1. At this time, the enlarged diameter portion 3 is also plastically deformed toward the distal end side of the head body 1, and accordingly, the distal end of the attachment portion 2A is slightly pushed out to the hole bottom side of the attachment hole 1D.

  However, when the diameter of the attachment portion 2A is increased by the press-fitting member in this way, the step portion 4 that has an outer diameter substantially equal to the inner diameter of the attachment hole 1D and can be slidably contacted with the attachment hole 1D is not expanded. In the manufacturing method using the connecting member 2 according to the first embodiment in which the step 4 is formed at the tip of the mounting portion 2A, the press-fitting member is press-fitted before the press-fitting portion reaches the step 4. stop. Therefore, in the head replaceable cutting tool (cutting head) manufactured by the manufacturing method of the first embodiment, as shown in FIG. In the meantime, the press-fitting part is stopped in front of the step part 4, thereby forming a recess 5 due to the diameter-increasing part 3 not being able to expand the diameter.

  The cutting head manufactured by joining the connecting member 2 to the head body 1 in this way is connected to the holder as a head exchangeable cutting tool manufactured according to the third and fourth embodiments described later, for example. The male thread portion 2B is attached by being screwed in, and the work material is cut by a cutting blade formed on the blade portion 1A of the head body 1 as a tool body made of a hard material. Further, the connecting member 2 in which the male screw portion 2B is formed in this way is formed of a metal material having lower hardness and higher toughness than the head main body 1, so that the thread is not chipped.

  In the connecting member 2 having the above-described structure and the manufacturing method using the connecting member 2, the inner diameter of the mounting hole 1D of the head body 1 can be directly confirmed by using the connecting member 2 itself instead of a pin gauge or the like. Even when the main body 1 is formed of the hard powder sintered material as described above and an error is likely to occur in the inner diameter of the mounting hole 1D depending on the sintered state, an optimum clearance is formed with respect to the inner diameter. The connecting member 2 having the enlarged diameter portion 3 can be selected reliably.

  For this reason, the need for a pin gauge or the like is eliminated, and the management becomes easy. Of course, in the plurality of types of connecting members 2 as described above, the enlarged diameter portion 3 and the stepped portion 4 are arranged in the order of the outer diameter. The optimal connecting member 2 can be selected by inserting the mounting portion 2A into the mounting hole 1D, and a connecting member having an enlarged diameter portion corresponding to a measurement result by a pin gauge or the like is selected. Compared to the above, it is possible to facilitate the selection work and improve the work efficiency, and it is also possible to prevent the selection error of the connecting member 2 from occurring.

  Moreover, since the step part 4 in the attachment part 2A of the connecting member 2 has an outer diameter that allows sliding contact with the attachment hole 1D of the cutting head 1, the step part 4 and the enlarged diameter part 3 of the attachment part 2A are used. If formed coaxially, the enlarged diameter portion 3 can be positioned coaxially with respect to the mounting hole 1D simply by inserting the mounting portion 2A. Therefore, the optimum clearance can be uniformly formed over the entire circumference between the mounting hole 1D and the enlarged diameter portion 3, and when the enlarged diameter portion 3 is plastically deformed and expanded in diameter. Since the attachment portion 2A can be uniformly and uniformly joined to the attachment hole 1D over the entire circumference, the joining strength of the connecting member 2 in the manufactured cutting head and the attachment stability to the holder can also be improved. .

  Further, in the present embodiment, the step 4 is formed at the tip of the mounting portion 2A that is the insertion direction side of the mounting portion 2A into the mounting hole 1D. Therefore, as described above, the step 4 When the mounting portions 2A of the plural types of connecting members 2 having different outer diameters are sequentially inserted into the mounting holes 1D, even if the mounting portions 2A cannot be fully inserted into the mounting holes 1D, the stepped portion 4 of the tip portion is attached. Since it can be confirmed that the outer diameter of the stepped portion 4 and the enlarged diameter portion 3 is larger than the outer diameter that forms the optimum clearance when caught in the opening portion of the hole 1D, the selection work of the connecting member 2 can be made more efficient. Can do.

  Even if the step portion 4 is formed at the tip of the mounting portion 2A, the press-fitting portion of the press-fitting member is stopped before the step portion 4 in the manufacturing method of the first embodiment. Further, the diameter up to the stepped portion 4 is not increased, and an excessive tensile stress does not act on the head body 1. Further, in the present embodiment, the mounting hole 1D is drilled to the engaging portion 1B having a large outer diameter in the head body 1, and when the mounting portion 2A is inserted into the mounting hole 1D during joining, Since the step portion 4 is disposed at the position, even if the press-fit portion of the press-fit member reaches the step portion 4, the tensile stress acting on the head body 1 is received by the large-diameter engaging portion 1B. It is possible to prevent cracks and the like from occurring.

  However, instead of forming the stepped portion 4 at the distal end portion on the insertion direction side of the mounting portion 2A in this way, the connecting member 2 and the connecting member of the second embodiment of the present invention shown in FIGS. 5 and 6 As in the second embodiment of the method for manufacturing a head-exchangeable cutting tool (cutting head) 2, the stepped portion 4 is formed at the rear end portion on the rear side in the insertion direction of the mounting portion 2 </ b> A into the mounting hole 1 </ b> D. You may do it. In the second embodiment, the same reference numerals are assigned to portions common to the first embodiment to simplify the description.

  In the second embodiment, as shown in FIG. 5A, the connecting member 2 is formed so that the stepped portion 4 is continuous with the distal end side of the male screw portion 2B. The mounting portion 2A is the diameter-expanded portion 3 up to the tip. Further, as shown in FIG. 5B, the inner peripheral portion of the connecting member 2 is a small diameter portion 2C having a diameter smaller than the outer diameter of the press-fit portion of the press-fit member as shown in FIG. The inner peripheral portion of the stepped portion 4 and the male screw portion 2B is a large-diameter portion 2D that is slightly larger in diameter than the press-fit portion outer diameter of the press-fit member.

  Also in the second embodiment, a plurality of types of connecting members 2 having different outer diameters of the enlarged diameter portion 3 and the stepped portion 4 are prepared. For example, the attachment portion 2A is arranged in order from the smallest outer diameter. The connecting member 2 immediately before the connecting member 2 which is inserted into the mounting hole 1D of the head body 1 and the stepped portion 4 is caught in the opening of the mounting hole 1D has an optimum clearance with the mounting hole 1D. It can be judged that it forms. Accordingly, it is possible to select the connecting member 2 that efficiently forms an optimum clearance without using a pin gauge or the like as in the first embodiment.

  6A, when the attachment portion 2A of the connecting member 2 is inserted into the attachment hole 1D and the press-fitting member is inserted into the inner peripheral portion of the connecting member 2 from the rear end side, the large-diameter portion 2D is Since the step portion 4 extends to the step portion 4, the diameter of the step portion 4 does not increase. When the press-fitted portion reaches the small diameter portion 2C, the diameter expansion portion 3 is plastically deformed to increase the diameter, and FIG. As shown, the outer peripheral surface closely contacts the inner peripheral surface of the mounting hole 1D and engages with the recess. Therefore, as in the first embodiment, it is possible to avoid the occurrence of cracks due to excessive tensile stress acting on the head body 1.

  Further, in the second embodiment, the step portion 4 is thus formed at the rear end portion of the mounting portion 2A, so that the press-fit portion stops before the step portion 4 as in the first embodiment. There is no need to control the press-fitting of the member. In addition, since the step 4 is formed at the rear end of the mounting portion 2A in this way, it comes into sliding contact with the mounting hole 1D on the opening side, and the mounting positioned by the sliding contact of the step 4 is provided. Since the press-fitting member is press-fitted from the rear end side of the portion 2A and the diameter-expanded portion 3 is expanded, in this second embodiment, the diameter-expanded portion is maintained while being kept coaxial with the mounting hole 1D. It is easy to make it possible to prevent the inclination of the mounting portion 2A and the like more reliably and to join the enlarged diameter portion 3 to the mounting hole 1D more evenly.

  7 to 9 show a third embodiment of the present invention, and FIGS. 7, 10 and 11 show a fourth embodiment of the present invention. In the third and fourth embodiments, the present invention is applied to a method for manufacturing a holder for a head exchangeable cutting tool. This holder is made of a hard material such as cemented carbide, cermet, ceramics, etc., integrally formed with a holder body 11 as a tool body in this embodiment, and stainless steel having a lower hardness than the hard material forming the holder body 11. And a connecting member 12 made of a plastically deformable metal material such as steel such as die steel.

  In these third and fourth embodiments, the holder main body 11 has a common external multi-stage cylindrical shaft shape centered on the center line X as shown in FIG. 7, and most of the rear end side has a large diameter. The shank portion 11A has a neck portion 11B having a slightly smaller diameter than the shank portion 11A. Further, in order from the front end surface of the holder body 11 toward the rear end side, the chamfered portion 11C, a tapered hole portion 11D that gradually decreases in diameter toward the rear end side, and the same diameter as the rear end of the tapered hole portion 11D. The housing hole 11E having a constant inner diameter, a mounting hole 11F having a constant inner diameter slightly smaller than the housing hole 11E, and a diameter smaller than the mounting hole 11F to reach the rear end surface of the holder body 11. The penetrating through hole 11G is formed to be coaxial with the center line X.

  Of these, the tapered hole portion 11D is, for example, a taper shaft portion 1C in the head body 1 of a cutting head as a head replaceable cutting tool manufactured according to the first and second embodiments can be taper-fitted. The taper angle formed by the inner peripheral surface with respect to the center line X is made equal to the taper angle formed by the outer peripheral surface of the taper shaft portion 1C of the head body 1 with respect to the center line O, and the inner diameter thereof. In the state where the outer peripheral surface of the taper shaft portion 1C is in close contact with the inner peripheral surface of the taper hole portion 11D and the cutting head is attached to the holder as will be described later, the rear end surface of the engaging portion 1B of the head body 1 is the holder. It is set so as to come into contact with the front end surface of the main body 11.

  Further, the inner peripheral surface of the mounting hole 11F is not polished or the like as in the inner peripheral surface of the mounting hole 1D of the first and second embodiments, and the above-mentioned cemented carbide forming the holder body 11 or the like. For example, a surface roughness of 5 μm to 200 μm with a maximum height roughness Rz defined in JIS B 0601: 2001 (ISO 4287: 1997) is used. (However, the reference length is 0.8 mm, the cut-off value is λs = 0.005 mm, and λc is 0.8 mm), and the inner peripheral surface itself is the recess of the mounting hole 11F.

  In the third and fourth embodiments, the connecting member 12 attached to the holder main body 11 has a substantially multistage cylindrical shape centering on the center line C as shown in FIGS. 8 and 10. 9 is inserted into the mounting hole 11F from the front end side of the holder main body 11 and joined to the holder main body 11, and the inner peripheral portion thereof is shown in FIGS. 9 (c) and 11 (c). A female screw portion 12A is formed.

  As shown in FIGS. 8 and 10, the material 13 of the connecting member 12 is smaller in diameter than the inner diameter of the receiving hole portion 11E and smaller than the inner diameter of the mounting hole 11F, as shown in FIGS. 8 and 10 in common with the third and fourth embodiments. The flange portion 13A has a large outer diameter and the length in the center line C direction is smaller than the depth in the center line X direction of the receiving hole portion 11E, while the rear end portion is the length in the center line C direction. The attachment portion 13B is made smaller than the depth of the attachment hole 11F in the direction of the center line X.

  Then, a part of the attachment portion 13B in the direction of the center line X is the enlarged diameter portion 14 having a smaller diameter than the inner diameter of the attachment hole 11F, and the remaining diameter excluding the enlarged diameter portion 14 A step portion 15 having a larger diameter than the portion 14 and having an outer diameter capable of sliding contact with the inner peripheral surface of the mounting hole 11F is formed. In the third and fourth embodiments as well, the outer diameter of the step portion 15 is substantially equal to the inner diameter of the mounting hole 11F and is slightly smaller within the fitting tolerance range. The difference in the outer diameter of the enlarged diameter portion 14 is a constant difference in the diameter of, for example, 0.1 mm to 0.5 mm.

  Among these, in the raw material 13 of the third embodiment shown in FIG. 8, the center line of the mounting portion 13B, which is the front side in the insertion direction of the raw material 13 into the mounting hole 11F of the raw material 13, is the same as in the first embodiment. It is formed at the rear end portion in the C direction, and the attachment portion 13B portion between the step portion 15 and the flange portion 13A is the enlarged diameter portion. In addition, the inner peripheral portion of the material 13 has a flange portion 13A as a large diameter portion 13C in the center line C direction, and the entire attachment portion 13B as a small diameter portion 13D having a constant inner diameter smaller than the large diameter portion 13C. ing.

  On the other hand, in the material 13 of the fourth embodiment shown in FIG. 10, the step portion 15 is the center line C of the attachment portion 13B on the rear side in the insertion direction of the material 13 into the attachment hole 11F as in the second embodiment. It is formed at the front end in the direction so as to continue from the flange portion 13 </ b> A, and the entire attachment portion 13 </ b> B on the rear end side (front side in the insertion direction) from the step portion 15 is the enlarged diameter portion 14. Further, in the inner peripheral portion of the material 13 of the fourth embodiment, the portion from the flange portion 13A to the step portion 15 in the direction of the center line C is a large diameter portion 13C, and the expanded diameter portion on the rear end side from this. The 14 portion is a small diameter portion 13D having a constant inner diameter smaller than the large diameter portion 13C.

  In the third and fourth embodiments of the method for manufacturing a head exchangeable cutting tool (holder) according to the present invention using the connecting member 12 of the third and fourth embodiments, first, the mounting hole of the holder main body 11 is first attached. A material of a plurality of types of connecting members 12 having a size that allows the outer diameter of the step portion 15 to be in sliding contact with the designed inner diameter of 11F and an outer diameter that is slightly different from this. 13 is prepared. Also in these materials 13, the outer diameter difference of the enlarged diameter portion 14 with respect to the stepped portion 15 is made equal to each other within the above range.

  And the attachment part 13B in the raw material 13 of these connection members 12 is inserted in the attachment hole 11F in order from the thing with the small outer diameter of the step part 15, for example, and the step part 15 is caught in the opening part of the attachment hole 11F. When the mounting portion 13B cannot be inserted into the mounting hole 11F, the material 13 of the previous connecting member 12 has an optimum clearance between the inner peripheral surface of the mounting hole 11F and the outer peripheral surface of the enlarged diameter portion 14. As shown in FIGS. 9 (a) and 11 (a), the attachment portion 13B of the material 13 is inserted into the attachment hole 11F, and the flange portion 13A is formed at the hole bottom of the accommodation hole portion 11E. A press-fitting member (punch) is press-fitted into the inner peripheral portion of the material 13.

  Similarly to the first and second embodiments, this press-fitting member is a shaft-shaped member whose tip-side press-fitting portion has a maximum outer diameter, and this maximum outer diameter is within the connecting member 12. For example, the diameter is larger by 0.2 mm to 1.0 mm than the inner diameter of the small-diameter portion 13D, and slightly smaller than the inner diameter of the large-diameter portion 13C. The diameter-expanded portion 14 is enlarged, and the outer peripheral surface thereof is in close contact with the inner peripheral surface of the mounting hole 11F and engages with the concave portion. As shown in FIG. 9B and FIG. It is joined to the main body 11.

  Here, in the third embodiment shown in FIG. 9, as in the first embodiment, the press-fitting portion of the press-fitting member is press-fitted so as to stop before reaching the step portion 15 at the rear end portion of the attachment portion 13 </ b> B of the material 13. As a result, a recess 16 is formed between the step portion 15 and the expanded diameter portion 14. On the other hand, in the fourth embodiment shown in FIG. 11, such a control is not performed, and the press-fitting portion is located on the rear end side of the attachment portion 13 </ b> B of the material 13 as long as the press-fitting member does not collide with the bottom of the attachment hole 11 </ b> F. What is necessary is just to make it expand the diameter of the enlarged diameter part 14 substantially.

  After the material 13 is joined in this way, the female screw portion 12A is formed on the inner peripheral portion of the material 13 as shown in FIGS. 9 (c) and 11 (c), so that the material 13 is connected to the connecting member on the holder side. 12, a holder that can be connected by screwing the connecting member 2 of the cutting head manufactured by the first and second embodiments and the male and female screw portions 2B and 12A can be manufactured. When the cutting head is attached to the holder by connecting the connection members 2 and 12 as described above, the taper shaft portion 1C of the head body 1 is in close contact with the taper hole portion 11D of the holder body 11 as described above. The rear end surface of the joint portion 1B is in contact with the front end surface of the holder body 11.

  Accordingly, also in the third and fourth embodiments, the female thread portion 12A is formed in the connecting member 12 having high toughness as in the first and second embodiments. Never do. On the other hand, since the holder main body 11 is formed of a hard material such as cemented carbide having high hardness and high rigidity, it is possible to support the cutting head firmly and promote stable cutting.

  The connecting member 12 to be joined to the holder main body 1 has an optimal clearance between the enlarged diameter portion 14 and the mounting hole 11F among the plurality of types of materials 13, and the mounting portion 13B of the material 13 itself. Since it is selected by being inserted into the mounting hole 11F and joined to the holder main body 11, and the female thread portion 12A is formed on the material 13, a pin gauge or the like is not required and the efficiency of the selection work can be improved. . Further, since the stepped portion 15 is in sliding contact with the attachment hole 11F, the coaxiality between the enlarged diameter portion 14 and the attachment hole 11F can be ensured, and the clearance is entirely between the attachment hole 11F and the enlarged diameter portion 14. Therefore, even when the diameter-expanded portion 14 is plastically deformed and expanded in diameter, the outer peripheral surface is evenly brought into close contact with the inner peripheral surface of the mounting hole 11F and engaged with the recess. And stable joining can be achieved.

  Furthermore, in the third embodiment in which the step portion 15 is formed on the rear end side of the attachment portion 13B that is the front side in the insertion direction of the material 13 into the attachment hole 11F, this step portion 15 is the same as in the first embodiment. Since the attachment portion 13B is inserted into the attachment hole 11F, it can be quickly confirmed whether or not the step portion 15 can be slidably contacted with the attachment hole 11F. On the other hand, in the fourth embodiment in which the step portion 15 is formed on the distal end side of the mounting portion 13B that is the rear side in the insertion direction, the press-fitting portion stops before the step portion 15 as in the third embodiment. And it is easy to increase the diameter of the enlarged diameter portion 14 while maintaining the coaxiality of the enlarged diameter portion 14 and the attachment hole 11F, and it is possible to join the attachment holes 1F more evenly. .

  In the first to fourth embodiments, the male screw portion 2B is provided on the cutting head side like the connecting member 2 of the first and second embodiments, and the holder is used as in the third and fourth embodiments. Although the female screw portion 12A is formed on the side, these may be reversed. However, the head main body 1 of the cutting head is usually shorter in the direction of the center line O than the holder main body 11, and after joining the connecting member to such a head main body 1 while ensuring the necessary joining length. It is difficult to form the female thread portion, and particularly when the mounting hole 1D is formed in the small-diameter tapered shaft portion 1C formed in the head body 1 like the cutting heads in the first and second embodiments. Since it is more difficult to form a female screw portion on the inner peripheral portion of the connecting member joined to the mounting hole 1D, the male screw portion 2B is provided on the cutting head side and the female screw is provided on the holder side as in the above embodiment. It is desirable to form the portion 12A.

  Furthermore, when forming the female screw portion 12A on the holder side in this way, the diameter-expanded portion 14 is plastically deformed and expanded in the material 13 of the connecting member 12 as in the manufacturing methods of the third and fourth embodiments. Later, it is desirable to form a female screw portion 12 </ b> A on the inner peripheral portion of the material 13 to form the connecting member 12. Thus, the female thread portion 12A can be formed with the center line X of the holder body 11 as a reference, and the female thread portion 12A can be accurately formed coaxially with the shank portion 11A and the tapered hole portion 11D. .

  Further, the female screw portion 12A formed in this way has an inner circumference of the mounting hole 11F by expanding the diameter-expanded portion 14 of the material 13 of the connecting member 12 as shown in FIG. 9 (c) and FIG. 11 (c). It is desirable to overlap the area in close contact with the surface in the direction of the center line X, so that the inside of the connecting member 12 engaged with the recess (uneven surface) formed on the inner peripheral surface of the mounting hole 11F. The cutting force acting on the male screw portion 2B of the cutting head can be received on the circumferential side. In order to form the female screw portion 12A in this way, the female screw portion 12A is preferably formed after the diameter-expanded portion 14 of the material 13 is plastically deformed and expanded.

  In the first and third embodiments, the step portions 4 and 15 are formed on the front side in the insertion direction of the attachment portions 2A and 13B into the attachment holes 1D and 11F, and the second and fourth embodiments. In the embodiment, the step portions 4 and 15 are formed on the rear side in the insertion direction of the attachment portions 2A and 13B into the attachment holes 1D and 11F. The step portions 4 and 15 are center lines C of the attachment portions 2A and 13B. It may be in the center of the direction. In this case, the inner peripheral portions of the connecting member 2 and the material 13 may be the large diameter portions 2D and 13C at the positions of the step portions 4 and 15. Further, the step portions 4 and 15 may be formed at a plurality of locations, for example, at two locations on the front side and the rear side in the insertion direction of the mounting portions 2A and 13B in the mounting holes 1D and 11F.

  Further, in these first to fourth embodiments, the step portions 4 and 15 are formed in an annular shape extending around the entire circumference of the attachment portions 2A and 13B with the center line C as the center, but from the center line C to the outer peripheral surface. Steps whose diameter is larger than that of the expanded diameter portions 3 and 14 are formed at, for example, three or more locations at equal intervals in the circumferential direction, and the outer peripheral surfaces of these step portions are in sliding contact with each other. Then, after the attachment portions 2A and 13B are inserted into the attachment holes 1D and 11F, the enlarged diameter portions 3 and 14 may be plastically deformed.

  On the other hand, in the first and third embodiments in which the step portions 4 and 15 are formed on the front side in the insertion direction of the attachment portions 2A and 13B into the attachment holes 1D and 11F, the connecting member is located at the position of the step portions 4 and 15. 2 and the inner peripheral portion of the material 13 are small-diameter portions 2C and 13D. As described above, the press-fitting member is pressed into the inner periphery of the mounting portions 2A and 13B in the insertion direction, and the press-fitting portion is in front of the step portions 4 and 15. In this way, the expanded diameter portions 3 and 14 are plastically deformed and the stepped portions 4 and 15 are not deformed. However, even when the stepped portions 4 and 15 are formed on the front side in the insertion direction, the second portion As in the fourth embodiment, the inner peripheral portion of the connecting member 2 and the material 13 is the large diameter portions 2D and 13C at the positions of the step portions 4 and 15, and penetrates the inner peripheral portion without stopping the press-fitting portion in front of it. You may make it make it.

DESCRIPTION OF SYMBOLS 1 Head main body 1A Blade part 1B Engagement part 1C Tapered shaft part 1D, 11F Mounting hole 2, 12 Connecting member 2A, 13B Mounting part 2B Male thread part 3, 14 Expanded diameter part 4, 15 Step part 11 Holder main body 11A Shank part 11D Tapered hole 13 Material of connecting member 12 C Centerline of connecting members 2 and 12 and attachment portions 2A and 13B of material 13 O Centerline of head body 1 X Centerline of holder body 11

Claims (6)

  A cylindrical attachment portion of a connecting member made of a metal material having a hardness lower than that of the hard material is inserted into an attachment hole having a recess on an inner peripheral surface formed on a tool body made of a hard material, The part formed in the center line direction of the cylinder formed by the mounting part is plastically deformed so as to increase in diameter as an enlarged diameter part, and the outer peripheral surface of the expanded diameter part is brought into close contact with the inner peripheral surface of the mounting hole to engage with the concave part. In the method of manufacturing a head exchangeable cutting tool that joins the tool body and the connecting member by combining, the remaining portion excluding the enlarged diameter portion of the attachment portion of the connecting member is more than the enlarged diameter portion. Forming a step portion having an outer diameter that can be slidably contacted with the inner peripheral surface of the mounting hole, inserting the mounting portion into the mounting hole by sliding the step portion, and then expanding the diameter. A method for manufacturing a head exchangeable cutting tool, wherein the part is plastically deformed.   The step portion is formed on the front side in the insertion direction of the attachment portion into the attachment hole, the step portion is brought into sliding contact, the attachment portion is inserted into the attachment hole, and then the attachment in the enlarged diameter portion is performed. A press-fitting member having an outer diameter larger than the inner diameter of the portion is pressed into the inner periphery of the mounting portion in the insertion direction and stopped before the stepped portion, so that the enlarged-diameter portion is plastically deformed. The manufacturing method of the head exchange type cutting tool of Claim 1 to do.   The step portion is formed on the rear side in the insertion direction of the attachment portion into the attachment hole, and the inner diameter of the attachment portion in the step portion is made larger than the inner diameter of the attachment portion in the enlarged diameter portion. Is inserted into the mounting hole, and the outer diameter is larger than the inner diameter of the mounting portion in the enlarged diameter portion, and the outer diameter is smaller than the inner diameter of the mounting portion in the stepped portion. 2. The method for manufacturing a head exchangeable cutting tool according to claim 1, wherein the expanded diameter portion is plastically deformed by press-fitting a member into the inner periphery of the mounting portion in the insertion direction. 3.   The tool body is a head body of a cutting head of a head exchangeable cutting tool in which a cutting edge portion is formed at a front end portion and the attachment hole is formed at a rear end portion, and the attachment member includes the attachment portion. The method for manufacturing a head exchangeable cutting tool according to any one of claims 1 to 3, wherein a male screw portion is formed on the rear end side of the head.   The tool body is a holder body of a holder of a head exchangeable cutting tool in which the mounting hole is formed at the front end portion and the rear end portion is a shank portion, and the expansion member is formed on the inner peripheral portion of the connecting member. The method for manufacturing a head exchangeable cutting tool according to any one of claims 1 to 3, wherein the female thread portion is formed after the diameter portion is plastically deformed.   It is a connection member used for the manufacturing method of the head exchange type cutting tool as described in any one of Claims 1-5, Comprising: It has a cylindrical attachment part and the center of the cylinder which this attachment part makes | forms A step portion having an outer diameter that is larger in diameter than the enlarged diameter portion and that can be slidably contacted with the mounting hole of the tool body is formed in the remaining portion excluding the enlarged diameter portion. A connecting member characterized by being made.

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