JP4628113B2 - Throw-away cutting tool and throw-away tip - Google Patents

Description

  The present invention relates to a throw-away cutting tool and a throw-away tip, and more particularly, to a throw-away cutting tool and a throw-away tip capable of ensuring holding strength while preventing an increase in processing cost.

  The throw-away cutting tool is a tool configured such that a throw-away tip for performing cutting work is detachable from the main body. Generally, the throw-away tip is sandwiched between a pair of sandwiching portions formed by extending a slit along the axial direction from the distal end portion of the main body portion. The screw is then screwed into a screw passage hole formed in the throw-away tip and a screw insertion hole and a screw fastening hole formed through one and the other of the clamping portions, so that the throw-away tip is held in the main body. Is done.

  Here, the bottom portion of the throw-away tip and the contact portion at the end of the slit are formed in a flat shape in a side view, and the bottom portion and the contact portion are brought into close contact with the main portion of the throw-away tip. Is installed.

  However, in the above-mentioned throw-away type cutting tool, depending on the hole position accuracy of the screw passage hole of the throw-away tip, the bottom surface portion and the contact portion are not in close contact with each other, and a gap is generated. Such a gap causes deterioration of the cutting edge position accuracy, and accordingly, the cutting accuracy is impaired.

Japanese Patent Application Laid-Open No. 2002-46011 discloses a chip rear end surface (bottom surface portion) having a V-shape so that the thickness dimension of the chip gradually decreases toward the rear end side of the main body, and the chip receiver. A technique is described in which a surface (contact portion) is formed of a V-shaped groove corresponding to the chip rear end surface, and a slit is extended from the bottom surface portion of the V-shaped groove toward the rear end side of the main body. According to this technology, the tip clamping portion (clamping portion) presses the throw-away tip by tightening the clamp screw (screw), and the V-shaped groove presses the tip rear end surface toward the tip side due to elastic deformation of the main body portion. . As a result, the rear end face of the chip and the V-shaped groove are in close contact with each other, the above-described deterioration of the edge position accuracy can be prevented, and cutting accuracy can be ensured.
JP 2002-46011 A (paragraph [0005], FIG. 1 etc.)

  However, in the above-described throw-away cutting tool, it is necessary to provide a slit in order to elastically deform the main body. As a result, there is a problem that the processing cost increases.

  On the other hand, when such a slit is not provided, the main body cannot be sufficiently elastically deformed. Therefore, the V-shaped groove cannot press both sides of the V-shaped chip rear end surface toward the front end side, and the cutting resistance at the time of cutting is applied only to the surface on the rear side in the cutting direction of the chip rear end surface. As a result, there is a problem that the entire area of the rear end face of the chip cannot be effectively used and the holding strength is lowered.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a throw-away cutting tool and a throw-away tip capable of ensuring holding strength while preventing an increase in processing cost. It is said.

In order to achieve this object, the throw-away cutting tool according to claim 1 is provided at a pair of sandwiching portions formed by extending a slit along the axial direction from a tip portion and an end portion of the slit. A main body portion that has a screw insertion hole formed in one of the contact portion and the clamping portion and a screw fastening hole formed in the other and is rotated around an axis, and is in contact with the contact portion A throw-away tip having a bottom surface portion and a screw passage hole communicating with the screw insertion hole and the screw fastening hole when the bottom surface portion is in contact with the contact portion, and the screw insertion hole and the screw passage hole. A screw that passes through and is screwed into the screw fastening hole, and the bottom surface portion of the throw-away tip is positioned with the shaft core interposed between the throw-away tip and the throw-away tip. The thickness of the away tip is the main body It is configured to be inclined so as to gradually decrease toward the contact portion, and one end side of the inclined surface is located on the front side in the cutting direction with respect to a virtual plane passing through the center of the throw-away tip in the thickness direction, and others first and second inclined bottom surface portion of the pair of end side Ru is configured to be positioned in the cutting direction rear side of the virtual plane, while being continuously to the one end side of the first and second inclined bottom surface portion Formed at both ends in the width direction of the throw-away tip, formed at both ends in the direction perpendicular to the shaft core in a front view, and having an inclination angle larger than the first and second inclined bottom surface portions with the virtual plane. comprising first and second communicating portions inclined, the said abutment portion comprises a first and a second inclined abutment portion said first and second inclined bottom surface portion is in contact respectively, the second 1 and 2 inclined bottom part and said 1st and 2nd inclination In a state in which the contact portion is in contact, the center axis of the screw insertion hole is eccentric to the rear end side of the main body portion with respect to the center axis of the screw fastening hole and the screw passage hole, and And when the second inclined bottom surface portion is in contact with the first and second inclined contact portions, a gap is provided between the first and second connecting portions and the first and second inclined contact portions. Is formed .

Indexable cutting tool according to claim 2, wherein, in the indexable cutting tool according to claim 1 Symbol placement, inclination angle is approximately 30 degrees or more and forming the first and second inclined bottom surface portion and the imaginary plane Each is set to approximately 75 degrees or less.

Indexable cutting tool according to claim 3, wherein, in the indexable cutting tool according to claim 1 or 2, wherein the abutment portion is intended to be configured in a substantially V-shape in the insertion direction when viewed in the screw The bottom surface portion includes a bottom surface central portion interposed between the first and second inclined bottom surface portions, and the first and second inclined bottom surface portions are in contact with the first and second inclined contact portions. In this case, a gap is formed between the center portion of the bottom surface and the contact portion.

A throw-away tip according to a fourth aspect is used for the throw-away cutting tool according to any one of the first to third aspects.

According to the throw-away cutting tool of the first aspect, the throw-away tip is sandwiched between the pair of sandwiching portions formed by extending the slit along the axial direction from the tip of the main body. The bottom surface portion of the throw-away tip includes a pair of first and second inclined bottom surface portions that are positioned with the shaft core interposed between the first and second inclined bottom surface portions, and the first and second inclined bottom surface portions are slits. The first and second inclined abutting portions of the abutting portions provided at the end portions of the abutting portions respectively abut. In such a contact state, the screw passes through a screw insertion hole formed in one of the holding portions and a screw passage hole formed in the throw-away tip, and a screw fastening hole formed in the other of the holding portions; Screw together. In this case, the first and second inclined bottom surface portions are configured to be inclined so that the thickness dimension of the throw-away tip gradually decreases toward the contact portion of the main body portion, and one end side of the inclined surface is slowed down. located in the cutting direction front side than the virtual plane passing through the thickness direction center of the away tip, and the other end is configured to be positioned in the cutting direction after the lateral side of the imaginary plane. Thereby, the 1st and 2nd inclination bottom face part can ensure the contact area with a 1st and 2nd inclination contact part at the time of a cutting direction at the time of cutting. Therefore, it is not necessary to dispose a slit at the bottom surface of the V-shaped groove as in the conventional main body, and the contact area of the bottom surface can be effectively used for the cutting resistance at the time of cutting. As a result, there is an effect that the holding strength of the throw-away tip can be secured while preventing an increase in processing cost.

Further, the bottom portion of the throw-away tip is continuously provided on the other end of the first and second inclined bottom surface portion, the first and second communication set inclined at a large inclination angle than the first and second inclined bottom surface portion Department. Thus, when the first and second inclined bottom surface portion is in contact with the first and second inclined abutment portion, the first and second inclined continuously provided portion and first and second inclined abutment portion Since a gap is formed between them, a space for pressing the throw-away tip toward the main body side can be secured. As a result, there is an effect that the first and second inclined bottom surface portions and the first and second inclined contact portions can be reliably contacted to firmly fix the throw-away tip to the main body portion.

Further, since the first and second connecting portions are inclined at a larger inclination angle than the first and second inclined bottom surface portions with respect to the virtual plane , the bottom surface portion is tapered toward the main body portion side. There is an effect that it is possible to prevent the damage on the bottom surface side of the throw-away tip.
In addition, when the first and second inclined bottom surface portions and the first and second inclined contact portions are in contact with each other, the central axis of the screw insertion hole is relative to the central axis of the screw fastening hole and the screw passage hole. Since it is eccentric to the rear end side of the main body, when the screw is screwed, the throw-away tip is pressed to the base end side of the main body. As a result, since the inclined bottom surface portion presses the inclined contact portion, there is an effect that the throw away tip can be firmly fixed to the main body portion and the mounting positional accuracy can be ensured.

According to the indexable cutting tool according to claim 2, in addition to the effects of the throw-away cutting tool according to claim 1 Symbol placement, angle of inclination and the imaginary plane and the first and second inclined bottom surface portion is approximately The angle is set to 30 degrees or more and approximately 75 degrees or less. Here, when the inclination angle formed by the first and second inclined bottom surface portions and the virtual plane is larger than approximately 75 degrees, the first and second inclined bottom surface portions are the first and second inclined contact portions. When abutting, the abutting area cannot be secured rearward in the cutting direction. On the other hand, when the inclination angle formed by the first and second inclined bottom surface portions and the virtual plane is smaller than about 30 degrees, the bottom surface portion is tapered toward the main body portion side, so that rigidity can be ensured. This is not possible and the bottom surface is easily damaged. As described above, by setting the inclination angle formed by the first and second inclined bottom surface portions and the virtual plane to be approximately 30 degrees or more and approximately 75 degrees or less, it is possible to achieve both of the above-described problem solving. There is.

According to the indexable cutting tool according to claim 3, in addition to the effects of the throw-away cutting tool according to claim 1 or 2, the contact portion is configured to substantially V-shaped in the insertion direction when viewed in the screw And the bottom face part is provided with the bottom face center part interposed by the 1st and 2nd inclination bottom face part. Accordingly, when the first and second inclined bottom surface portions are brought into contact with the first and second inclined contact portions, a gap is formed between the bottom surface central portion and the contact portion, so that the throw-away tip is formed. It is possible to secure a space for pressing the to the main body side. As a result, there is an effect that the first and second inclined bottom surface portions and the first and second inclined contact portions can be reliably contacted to firmly fix the throw-away tip to the main body portion.

According to the throw-away tip according to claim 4, the same effect as the throw-away tip used in the throw-away cutting tool according to any one of claims 1 to 3 can be obtained.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. FIG. 1 is a front view of the throw-away cutting tool 1 according to the first embodiment of the present invention. In addition, in FIG. 1, illustration of the axial direction length of the main-body part 3 is abbreviate | omitted.

  First, the overall structure of the throw-away cutting tool 1 will be described with reference to FIG. The throw-away cutting tool 1 includes a throw-away tip 2 having a cutting edge, a main body portion 3 that sandwiches and fixes the throw-away tip 2, and a screw 4 and a holder (not shown). It is a tool that cuts metal or the like by transmitting the rotational force of a processing machine such as a milling machine or a machining center through the tool.

  In addition, a contact portion between the throw-away tip 2 and the main body 3 is schematically illustrated using a broken line.

  The throw-away tip 2 is for cutting a workpiece with a cutting edge disposed on the peripheral edge thereof, and is configured to be detachable from the main body portion 3. Thereby, when the cutting edge reaches the end of its life, it is possible to continue the processing without re-grinding by replacing with another chip. The material of the throw-away tip 2 is composed of cemented carbide, high-speed tool steel, or the like.

  Further, the throw-away tip 2 in the present embodiment is configured as a ball end mill, but is not necessarily limited thereto, and may be configured by a square end mill, a radius end mill, a drill, or the like.

  The main body 3 is held by the above-described processing machine and transmits the rotational force of the processing machine to the throw-away tip 2 attached to the tip. In addition, the material of the main-body part 3 is comprised from a cemented carbide, high speed tool steel, etc.

  The screw 4 has a thread and is for fixing the throw-away tip 2 to the main body 3. Details will be described later.

  Next, with reference to FIG. 2, attachment of the throw-away tip 2 will be described. 2A is a cross-sectional view of the main body 3 taken along the line IIb-IIb in FIG. 1, and FIG. 2B is a cross-sectional view of the throw-away cutting tool 1 taken along the line IIb-IIb in FIG. . 2A and 2B, illustration of the axial length of the main body 3 is omitted.

  The main body 3 is for transmitting the rotational force of the processing machine to the throw-away tip 2 as described above, from the distal end side (left side in FIG. 2 (a)) to the proximal end side (right side in FIG. 2 (a)). ), A pair of sandwiching portions 3a formed by the slit 3b, a screw hole 5 formed through the sandwiching portion 3a, and a terminal side of the slit 3b (FIG. 2A). And abutting portion 6 positioned on the right side).

  The slit 3b extends from the distal end side to the proximal end side of the main body 3, and is configured such that the throw-away tip 2 can be attached. The dimension of the slit 3b in the axial direction (left and right direction in FIG. 2A) is set smaller than the axial dimension of the throw-away tip 2 (see FIG. 2B). The part protrudes from the tip of the main body part 3, and cutting is possible.

  Further, the dimension perpendicular to the axis of the slit 3b (the vertical direction in FIG. 2A) is set to be approximately equal to the thickness dimension of the throw-away tip 2. Thereby, it is possible to prevent the throw-away tip 2 from wobbling in the direction perpendicular to the axis and to secure the positional accuracy.

  The clamping part 3a is a part which forms the upper and lower surfaces (FIG. 2B upper and lower) of the slit 3b, and plays a role of clamping the throw-away tip 2.

  The screw hole 5 is formed so as to penetrate the holding portion 3a and be screwable with the screw 4 (see FIG. 2B). The screw insertion hole 5a formed so as to penetrate the one holding portion 3a The screw clamping hole 5b is formed through the other holding portion 3a.

  The screw insertion hole 5a is formed in a taper shape whose diameter increases toward the outer side in the radial direction of the main body 3 (upward in FIG. 2 (a)), and the head 4a of the screw 4 (see FIG. 2 (b)). It is comprised so that abutment is possible. In addition, the shape of the screw insertion hole 5a is not necessarily limited to the tapered shape, and can be appropriately changed according to the shape of the head 4a.

  The screw fastening hole 5b has a female screw threaded on the inner peripheral surface thereof, and is configured to be screwable with the male screw of the shaft portion 4b of the screw 4 (see FIG. 2B).

  The contact part 6 is a part located at the terminal part of the slit 3b, and includes a first inclined contact part 6a inclined toward the insertion direction of the screw 4 (downward in FIG. 2A), and the first thereof. The inclined contact portion 6b and the second inclined contact portion 6b having an inclination in the opposite direction (upward direction in FIG. 2A) are configured. The first and second inclined contact portions 6a and 6b are configured to be able to contact the first and second inclined bottom surface portions 7b and 7c (see FIG. 3), respectively. Details will be described later.

  As shown in FIG. 2 (b), when fixing the throwaway tip 2 to the main body 3, the throwaway tip 2 is sandwiched between the sandwiching portions 3a and 3a, and the inclined bottom surface portion 7b of the throwaway tip 2 is disposed. 7c (see FIG. 3) is brought into contact with the inclined contact portions 6a and 6b. In this abutted state, the screw 4 is screwed into the screw fastening hole 5b while passing through the screw insertion hole 5a and the screw passage hole 2a formed in the substantially central portion of the throw-away tip 2.

  As described above, the set screw 4 is configured to be screwable with the screw hole 5 and includes a tapered head portion 4a and a shaft portion 4b connected to the head portion 4a. Yes.

  The full length dimension of the set screw 4 (vertical dimension in FIG. 2B) is set smaller than the diameter dimension of the main body 3. Thereby, when the set screw 4 is attached to the main body part 3, one end of the set screw 4 is prevented from protruding from the outer peripheral surface of the main body part 3, and the cutting process can be performed smoothly.

  The head 4a is formed in a taper shape corresponding to the taper surface of the screw insertion hole 5a, and is configured such that the taper surfaces can come into contact with each other. As described above, the shape of the head 4a is not necessarily limited to a tapered shape, and may be configured as a hexagonal head, a square head, or the like.

  The shaft portion 4b has a screw threaded on the outer peripheral surface thereof, and is configured to be screwable with the female screw of the screw fastening hole 5b described above.

  The central axis of the screw insertion hole 5a is eccentric to the base end side of the main body 3 (right side in FIG. 2 (b)) with respect to the central axis of the screw fastening hole 5b. When the first and second inclined bottom surface portions 7b and 7c are in contact with the first and second inclined contact portions 6a and 6b, the central axis of the screw passage hole 2a is the central axis of the screw fastening hole 5b. Is consistent with That is, the central axis of the screw insertion hole 5a is eccentric to the rear end side of the main body 3 with respect to the central axes of the screw fastening hole 5b and the screw passage hole 2a.

Thereby, when the screw 4 is screwed together, the throw-away tip 2 is pressed toward the base end side of the main body 3. As a result, the inclined bottom surface portions 7b and 7c press the inclined contact portions 6a and 6b, so that the throw-away tip 2 can be firmly fixed to the main body portion 3 and the mounting positional accuracy can be ensured. The eccentricity difference is approximately 0.1 mm.

  Further, a gap is formed between the bottom center portion 7 a of the throw-away tip 2 and the contact portion 6. Thereby, the space for pressing the throw away tip 2 to the base end side (FIG. 2 (b) right direction) of the main-body part 3 is securable. As a result, as described above, the first and second inclined bottom surface portions 7b and 7c and the first and second inclined contact portions 6a and 6b are securely brought into contact with each other, so that the throw-away tip 2 is brought into contact with the main body portion 3. It can be firmly fixed.

  Next, the throw-away tip 2 will be described with reference to FIG. 3A is a left side view of the throw-away tip 2, FIG. 3B is a front view of the throw-away tip 2, and FIG. 3C is a right side view of the throw-away tip 2. FIG. It is. 3A corresponds to a side view of the throw-away tip 2 viewed from the left side of FIG. 3B and FIG. 3C corresponds to the throw-away tip 2 viewed from the right side of FIG. 3B. Further, the throw-away tip 2 in the present embodiment is rotated clockwise around the axis O in the distal direction view (viewed from the lower side in FIG. 3) from the bottom surface portion 7 during the cutting process.

  As shown in FIG. 3 (b), the throw-away tip 2 has a tip end side (upper side in FIG. 3 (b)) formed in a substantially arc-like plate shape, and is disposed at the peripheral portion as described above. A workpiece is cut with a cutting edge. The throw-away tip 2 mainly includes a screw passage hole 2a that is formed through substantially the center of the flat surface portion, and a bottom surface portion 7 that is configured to be in contact with the contact portion 6 (see FIG. 2). It is prepared for.

  The screw passage hole 2a is a substantially circular hole formed through substantially the center of the flat portion of the throw-away tip 2, and its diameter is a shaft portion 4b (see FIG. 2B) of the screw 4 (see FIG. 2B). 2 (see FIG. 2 (b)) is set to be approximately the same as the outer diameter dimension, and the screw 4 can be inserted.

  The bottom surface portion 7 is configured to be able to contact the contact portion 6 and is configured to be able to contact the first and second inclined contact portions 6a and 6b (see FIG. 4). The bottom surface portions 7b and 7c and the bottom surface central portion 7a interposed between the first and second inclined bottom surface portions 7b and 7c are configured.

  The bottom surface central portion 7a is set to approximately 90 degrees with respect to the surface and the axis O, and is interposed between the first and second inclined bottom surface portions 7b and 7c. Thereby, as above-mentioned, when the throw away tip 2 is attached to the main-body part 3, a clearance gap can be formed between the bottom face center part 7a and the contact part 6. FIG.

  In the present embodiment, the angle formed by the surface of the bottom center portion 7a and the axis O is set to approximately 90 degrees, but is not necessarily limited to this and is smaller than an inclination angle β described later. Any value is acceptable. That is, when the throw-away tip 2 is attached to the main body portion 3, a gap may be formed between the bottom surface center portion 7 a and the contact portion 6.

  The first and second inclined bottom surface portions 7b and 7c gradually move toward the side (lower side in FIG. 3) in which the width dimension in the direction perpendicular to the axis O (the left-right direction in FIG. 3 (b)) contacts the contact portion 6. It is set to decrease. Note that the inclination angle β formed by the first and second inclined bottom surface portions 7b, 7c and the extended surface of the bottom surface central portion 7a in the present embodiment is set to approximately 30 degrees, but is not necessarily limited thereto. Instead, it can be appropriately changed within a range of approximately 0 degrees or more and approximately 45 degrees or less.

  Further, as shown in FIGS. 3A and 3C, the first and second inclined bottom surface portions 7b and 7c are on the side where the thickness dimension of the throw-away tip 2 contacts the contact portion 6 (FIG. 3A ) And (c) downward (to the lower side). Then, one end side of the inclined surface (the lower side in FIGS. 3A and 3C) is on the front side in the cutting direction with respect to the virtual plane passing through the center of the throw-away tip 2 in the thickness direction (FIGS. 3A and 3C). The other end side of the inclined surface (upper side in FIGS. 3A and 3C) is located on the rear side in the cutting direction (left side in FIGS. 3A and 3C). Yes.

  Here, when the throw-away tip 2 is attached to the main body 3, at least a part of the cutting resistance at the time of cutting is such that the surface of the bottom surface portion 7 on the rear side in the cutting direction and the cutting direction of the contact portion 6. Added to the contact surface with the front surface. In this case, as described above, since the inclined surfaces of the first and second inclined bottom surface portions 7b and 7c face rearward in the cutting direction, the first and second inclined contact portions at the time of cutting. The contact area with 6a, 6b can be ensured behind the cutting direction. Therefore, it is unnecessary to provide a slit on the bottom surface of the V-shaped groove as in the case of the conventional main body, and the first and second inclined bottom surfaces 7b and 7c are brought into contact with the cutting resistance at the time of cutting. The area can be used effectively. As a result, it is possible to ensure the holding strength of the throw-away tip 2 with respect to the main body 3 while preventing an increase in processing cost.

The inclination angle α formed by the first and second inclined bottom surface portions 7b and 7c and the virtual plane passing through the center of the throw-away tip 2 in the present embodiment is set to approximately 60 degrees. However, the present invention is not necessarily limited to this, and may be set to approximately 30 degrees or more and approximately 75 degrees or less. The inclination angle described in claim 2 means the inclination angle α.

  Here, when the inclination angle α is larger than approximately 75 degrees, the first and second inclined bottom surface portions 7b and 7c are cut when they are in contact with the first and second inclined contact portions 6a and 6b. A contact area cannot be ensured in the rearward direction.

  On the other hand, when the inclination angle α is smaller than approximately 30 degrees, the bottom surface portion 7 has a tapered shape toward the contact portion 6 side (lower side in FIGS. 3A and 3C). That is, since the bottom surface portion 7 side (the lower side in FIG. 3) of the throw-away tip 2 is thin, rigidity cannot be ensured, and the first and second inclined bottom surface portions 7b and 7c are easily damaged.

  As described above, by setting the inclination angle α to approximately 30 degrees or more and approximately 75 degrees or less, it is possible to secure a contact area rearward in the cutting direction and prevent damage to the first and second inclined bottom surface portions 7b and 7c. It is possible to achieve both.

  Further, as shown in FIGS. 3A and 3C, the bottom surface portion 7 is located on the front side in the cutting direction of the first and second inclined bottom surface portions 7b and 7c (right side in FIGS. 3A and 3C). First and second continuous portions 7b1 and 7c1 provided at one end are provided. In the first and second connecting portions 7b1 and 7c1, the angle between the plane and the virtual plane passing through the center of the throw-away tip 2 in the thickness direction (vertical direction in FIG. 3B) is set to approximately 90 degrees. Therefore, when the first and second inclined bottom surface portions 7b and 7c contact the first and second contact portions 6a and 6b, the first and second connecting portions 7b1 and 7c1 and the first And a clearance gap is formed between 2nd contact part 6a, 6b. As a result, a space for pressing the throw-away tip 2 toward the main body 3 side (the lower side in FIG. 3) can be secured, so that the first and second inclined bottom surface portions 7b and 7c and the first and second abutting tips can be secured. The throw-away tip 2 can be firmly fixed to the main body 3 by reliably contacting the contact portions 6a and 6b.

  In addition, since the first and second connecting portions 7b1 and 7c1 have an angle formed between the plane and a virtual plane passing through the center of the throw-away tip 2 in the thickness direction, the first and second The first and second slopes of the throw-away tip 2 are prevented by preventing the two continuous portions 7b1 and 7c1 from being tapered toward the contact portion 6 side (the lower side in FIGS. 3A and 3C). It is possible to prevent the bottom surface portions 7b and 7c from being damaged.

  In the present embodiment, the angle formed by the plane of the first and second connecting portions 7b1 and 7c1 and the virtual plane passing through the center in the thickness direction of the throw-away tip 2 is set to approximately 90 degrees. However, the present invention is not necessarily limited to this, and the inclination angle formed between the virtual plane passing through the center in the thickness direction of the throw-away tip 2 and the first and second connecting portions 7b1 and 7c1 may be larger than the inclination angle α. Thereby, it can prevent that the 1st and 2nd connection part 7b1 and 7c1 become a taper shape toward the contact part 6 side.

  Next, with reference to FIG. 4, attachment of the throw-away tip 2 will be described. FIG. 4 is a cross-sectional view of the throw-away cutting tool 1 taken along line IV-IV in FIG. In addition, in FIG. 4, illustration of the axial direction length of the main-body part 3 is abbreviate | omitted. In addition, the throw-away type cutting tool 1 in the present embodiment is assumed to be rotated clockwise from the main body 3 toward the distal end direction (viewed from the lower side to the upper side in FIG. 4) when cutting.

  As shown in FIG. 4, when the throw-away tip 2 is attached to the main body 3, the first and second inclined contact portions 6a and 6b having an inclination toward the front in the cutting direction and the rear in the cutting direction. The first and second inclined bottom surface portions 7b and 7c having an inclination are configured to be able to contact each other. Thereby, as above-mentioned, the contact area of the bottom face part 7 can be used effectively with respect to the cutting resistance at the time of cutting.

  Further, when the screw 4 (see FIG. 2 (b)) is viewed in the insertion direction (viewed in the direction perpendicular to the plane of FIG. 4), the contact portion 6 of the main body 3 is configured in a substantially V shape. A gap can be formed between the central portion 7a and the bottom center portion 7a.

  Here, when the contact portion 6 is configured corresponding to the shape of the bottom surface portion 7, the inclined surfaces that are inclined with respect to the axis O and the substantially right-angled surfaces contact each other. . In such a case, in order to effectively use the contact area of the bottom surface portion 7 with respect to the cutting resistance at the time of cutting, it is necessary to prevent only the right-angle surfaces from contacting each other. For this reason, the processing precision of the contact part 6 and the bottom face part 7 is required. Therefore, as described above, the contact portion 6 is formed in a substantially V shape, so that the processing accuracy is not required and the processing cost can be reduced.

  Next, a second embodiment will be described with reference to FIG. In the first embodiment, the case where the first and second inclined bottom surface portions 7b and 7c are configured to be inclined in the direction opposite to the axis O has been described. In the second embodiment, The first and second inclined bottom surface portions 17b and 17c are configured to have an inclination toward the axis O. 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. 5A is a front view of the throw-away tip 12 in the second embodiment, and FIG. 5B is a rear end view of the throw-away tip 12. Note that the throw-away tip 12 in the present embodiment is viewed from the bottom surface portion 17 when viewed in the distal direction (viewed from the lower side to the upper side in FIG. 5A), and the axis O is rotated clockwise (FIG. 5B). Shall be rotated.

  The bottom surface portion 17 located on the lower end surface of the throw-away tip 12 is a portion configured to be able to contact an abutting portion (not shown), and is formed so as to face the shaft core O. Inclined bottom surface portions 17b, 17c and a bottom surface central portion 17a interposed between the first and second inclined bottom surface portions 17b, 17c are configured.

  The bottom surface central portion 17a is set at an angle of 90 degrees between the surface and the axis O, and is interposed at one end of the first and second inclined bottom surface portions 17b and 17c on the axis O side.

  As shown in FIG. 5A, the first and second inclined bottom surface portions 17b and 17c are disposed at positions where the inclined surfaces face each other, and the distance between the opposed surfaces is the contact portion side (FIG. 5 ( a) It is set to gradually increase toward the lower side. The inclination angle γ formed by the first and second inclined bottom surface portions 17b, 17c and the bottom surface central portion 17a in the present embodiment is set to approximately 30 degrees, but is not necessarily limited thereto. It can be appropriately changed within a range of approximately 0 degrees or more and approximately 45 degrees or less.

  Further, as shown in FIG. 5B, the first and second inclined bottom surface portions 17b and 17c are inclined toward the front in the cutting direction, and one end on the front side in the cutting direction is the thickness of the throw-away tip 12. It is located in front of the cutting direction with respect to a virtual plane passing through the center in the vertical direction (vertical direction in FIG. 5B). Thereby, the contact area of the 1st and 2nd inclination bottom face parts 17b and 17c can be used effectively with respect to the cutting resistance at the time of cutting.

  The bottom surface portion 17 includes first and second connecting portions 17b1 and 17c1 that are connected to one end of the first and second inclined bottom surface portions 17b and 17c on the front side in the cutting direction. Since the first and second connecting portions 17b1 and 17c1 have an angle formed between the plane and a virtual plane passing through the center of the throw-away tip 12 in the thickness direction, the first and second A gap is formed between the first and second inclined bottom surface portions 17b and 17c and the contact portion when the inclined bottom surface portions 17b and 17c contact the contact portion (not shown). Thereby, it is possible to secure a space for pressing the throw-away tip 12 toward the contact portion side (the front side in FIG. 5B).

  Moreover, since the angle which the 1st and 2nd connection part 17b1, 17c1 makes | forms the plane and the virtual plane which passes along the thickness direction center of the throwaway tip 12 is set to about 90 degree | times, the bottom face part 17 is It is possible to prevent the first and second inclined bottom surface portions 17b and 17c of the throw-away tip 12 from being damaged by preventing the tapered shape toward the contact portion side.

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

It is a front view of the throw away type cutting tool in a 1st embodiment of the present invention. (A) is sectional drawing of the main-body part in the IIb-IIb line | wire of FIG. 1, (b) is sectional drawing of the throw-away type cutting tool in the IIb-IIb line | wire of FIG. (A) is a left side view of the throw-away tip, (b) is a front view of the throw-away tip, and (c) is a right side view of the throw-away tip. It is sectional drawing of the throw-away type cutting tool in the IVb-IVb line | wire of FIG.2 (b). (A) is a front view of the throw-away tip in the second embodiment, and (b) is a rear end view of the throw-away tip.

DESCRIPTION OF SYMBOLS 1 Throw away type cutting tool 2,12 Throw away tip 2a Screw passage hole 3 Main-body part 3a Nipping part 3b Slit 4 Screw 5a Screw insertion hole 5b Screw fastening hole 6 Contact part 6a 1st inclination contact part 6b 2nd inclination contact Contact portion 7, 17 Bottom surface portion 7a, 17a Bottom center portion 7b, 17b First inclined bottom surface portion 7b1, 17b1 First connecting portion 7c, 17c Second inclined bottom surface portion 7c1, 17c1 Second connecting portion
α Inclination angle formed by first and second inclined bottom surfaces and virtual plane

Claims (4)

A pair of clamping parts formed by extending a slit along the axial direction from the tip part, a contact part provided at the terminal part of the slit, a screw insertion hole formed through one of the clamping parts, and the other A main body portion having a screw fastening hole to be formed and rotated about an axis; a bottom surface portion abutted on the abutting portion; and the screw when the bottom surface portion abuts on the abutting portion A throw-away type comprising: a throw-away tip having an insertion hole and a screw passage hole communicating with the screw fastening hole; and a screw that passes through the screw insertion hole and the screw passage hole and is screwed into the screw fastening hole In cutting tools,
The bottom portion of the throw-away tip is positioned with the shaft core in between when attached to the main body, and the thickness dimension of the throw-away tip gradually decreases toward the contact portion of the main body. It is configured to be inclined, and one end side of the inclined surface is located on the front side in the cutting direction with respect to the virtual plane passing through the center in the thickness direction of the throw-away tip, and the other end side is behind the virtual plane in the cutting direction first and second inclined bottom surface portion of the pair that will be configured to be located in, is formed in the widthwise ends of the cutting insert while being continuously to the one end side of the first and second inclined bottom surface portion The first and second connecting portions that are inclined at a larger inclination angle than the first and second inclined bottom surface portions, the inclination angle formed with the virtual plane ,
The contact portion includes first and second inclined contact portions with which the first and second inclined bottom surface portions are contacted, respectively .
When the first and second inclined bottom surface portions and the first and second inclined contact portions are in contact with each other, the central axis of the screw insertion hole is the central axis of the screw fastening hole and the screw passage hole. Against the rear end side of the main body,
When the first and second inclined bottom portions are in contact with the first and second inclined contact portions, the first and second connecting portions and the first and second inclined contact portions A throw-away type cutting tool characterized in that a gap is formed between them . It said first and second inclined bottom surface portion and the inclination angle and the virtual plane forms is characterized in that it is set respectively over 30 ° approximately and below approximately 75 degrees claim 1 Symbol placement of indexable cutting tool. The contact portion is configured in a substantially V shape when viewed in the insertion direction of the screw,
The bottom surface portion includes a bottom surface center portion interposed between the first and second inclined bottom surface portions,
When the first and second inclined bottom surface portions are in contact with the first and second inclined contact portions, a gap is formed between the bottom surface center portion and the contact portion. indexable cutting tool according to claim 1 or 2, characterized in that there. A throw-away tip used for the throw-away type cutting tool according to any one of claims 1 to 3 .

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