JP4804917B2 - brooch - Google Patents

Description

The present invention relates to a blow switch a plurality of cutting edges on the shaft of the elongated are arranged along the axial direction of the shaft portion.

  FIG. 18 is a diagram for explaining a cutting load acting on the broach 200, and FIG. 19 is a diagram for explaining a bending that occurs in the broach 200. In the broach 200, a plurality of cutting blades 210 protruding from the long shaft portion 211 are arranged in a plurality of stages at predetermined intervals in the axial direction, and each cutting blade 210 is a front portion of the shaft portion 211. It is formed to expand in a similar manner as it moves from the rear to the rear.

  Then, the front grip part 201 which is the front end portion of the shaft part 211 is firmly clamped at the clamping part of the broaching machine and moved toward the front side in the axial direction which is the cutting direction, so that the workpiece 100 is broached. It is configured as follows.

  There is also a broach 200 that performs broaching on the workpiece 100 by clamping and moving the front gripping portion 201 of the broach 200 and the rear gripping portion 202 that is the rear end portion of the broach 200 toward the front side in the axial direction.

  Conventionally, there is known a technology that extends the tool life of the broach by suppressing the abnormal wear such as chipping by coating the cutting edge with a hard coating made of cemented carbide as the tool material constituting each cutting edge of the broach. (For example, refer to Patent Document 1). The carbide broach has a characteristic that the cutting edge of the cutting edge is more easily chipped than a normal broach when it is cut with an excessive wear amount or an excessive cutting amount or an impact is applied.

JP 2001-239425 A

  As shown in FIG. 18, the cutting edge 210 during broaching has a back component force that is a load in a direction orthogonal to the main component force F that is the axial load of the broach 200 as a cutting load from the workpiece 100. W works.

  As shown in FIG. 19A, the back component force W is, for example, when the processing condition is a front gripping method in which only the front gripping portion 201 of the broach 200 is clamped and the broach 200 is moved toward the front side in the axial direction. , The amount of bending gradually increases as it shifts to the rear side of the broach 200, and causes the rear end portion of the broach 200 to become the maximum amount of bending δ 1.

  Further, as shown in FIG. 19B, the processing conditions are such that the front gripping part 201 and the rear gripping part 202 of the broach 200 are clamped and the broach 200 is moved at a predetermined moving speed and load toward the front side in the axial direction. In the case of the gripping method, a deflection in which the central portion in the axial direction has a maximum deflection amount δ2 is generated.

  The bending of the broach 200 further increases the back component force W acting on the cutting edge 210, generates a local compressive stress on the cutting edge of the cutting edge 210, generates abnormal wear such as chipping on the cutting edge 210, and advances it. It was a factor.

  Therefore, for example, when the processing condition is the front gripping method, the maximum deflection is generated in the rear area in the axial direction of the broach 200, and abnormal wear such as chipping occurs in the final finished blade which is generally hardly worn. The workpiece dimensional accuracy may change due to abnormal wear, and the tool life of the broach 200 may be shortened in a shorter time than normal wear.

  In addition, when the processing condition is the double gripping method, a slight chipping is first generated on the cutting edge 210 disposed in the central region in the axial direction of the broach 200 where the amount of bending becomes maximum, and then suddenly wears. As a result, abnormal wear occurs, the amount of cutting of the rear cutting edge 210 increases, the wear moves to the rear cutting edge 210 one after another, and the tool life of the broach 200 may be shortened in a shorter time than normal wear.

  In the case of a carbide broach, the cutting edge is lost due to the impact applied due to the bending of the broach, and there is a risk that the life of the broach will be shortened in a shorter time than normal wear.

Accordingly, an object of the present invention was made in view of these problems is to provide a blow switch capable of suppressing the reduction in resulting from tool life deflection brooch.

Broach with the first aspect for solving the above-mentioned problems, the front end portion and the rear end of Rutotomoni the shank plurality of cutting edges are arranged along the axial direction of the shaft portion in the shaft portion of the elongated The shaft portion is relatively relative to the workpiece in which the portion is clamped and a concave groove having a pair of vertical wall portions curved in a convex shape and a bottom wall portion connecting the tip portions of the vertical wall portions is formed. In the broach for cutting the workpiece by the cutting blades and performing broaching on the workpiece by moving it forward in the axial direction along the axial direction of the shaft, and disposed in the axial front region of the shaft portion, A first cutting edge that protrudes toward an intermediate portion in the groove depth direction of the pair of vertical wall portions and cuts the intermediate portion in the groove depth direction toward a machining allowance direction that is a groove width direction; and the shaft portion. Disposed in the central region in the axial direction of the first cut A second cutting edge whose cutting area is set to be smaller than a workpiece cutting area of the workpiece by the blade, and the second cutting edge has a vertical wall portion of the concave groove and a groove depth of the concave groove. It cuts along the cutting width direction which follows the curve of a pair of above-mentioned vertical wall part toward each of a groove depth direction tip part and a groove depth direction base end part from a direction middle part .

In the broach according to the second aspect of the present invention , a plurality of cutting blades are arranged on the long shaft portion along the axial direction of the shaft portion, and the front end portion and the rear end portion of the shaft portion are clamped. , Along the axial direction of the shaft portion relative to the workpiece formed with a concave groove having a pair of vertical wall portions curved in a convex shape and a bottom wall portion connecting the tip portions of the vertical wall portions. In the broach for cutting the workpiece with each of the cutting edges by moving the workpiece forward in the axial direction and broaching the workpiece, the broach is disposed in the axial front region of the shaft portion, and the pair of vertical walls Projecting toward the groove depth direction proximal end portion and the groove depth direction distal end portion of the groove, and projecting the groove depth direction proximal end portion and the groove depth direction distal end portion in the machining allowance direction, which is the groove width direction, respectively. First cutting edge that cuts toward the axial direction of the shaft portion A second cutting edge disposed in a central region and having a workpiece cutting area set smaller than a workpiece cutting area of the workpiece by the first cutting edge, Cutting width of the vertical wall portion of the concave groove along the curvature of the pair of vertical wall portions from the groove depth direction proximal end portion and the groove depth direction distal end portion toward the groove depth direction intermediate portion. It is characterized by cutting along the direction .

The invention described in claim 3 is the broach according to claim 1 or 2, further comprising a third cutting edge disposed in an axial rear side region of the shaft portion, and the third cutting edge. Has a shape in which the vertical wall portion of the concave groove is cut in the direction of the cutting allowance over the groove depth direction, and the workpiece cutting area by the third cutting edge is the workpiece by the second cutting edge. It is characterized by being set larger than the cutting area .

The broach according to the invention described in claim 4 has a plurality of cutting edges arranged in an elongated shaft portion in the axial direction of the shaft portion, and only the front end portion of the shaft portion is clamped, and the cross section is Axial direction along the axial direction of the shaft portion relative to the workpiece formed with a concave groove having a pair of vertical wall portions curved in a convex shape and a bottom wall portion connecting the tip portions of the vertical wall portions. In the broach for cutting the workpiece by the cutting blades by moving to the front side and subjecting the workpiece to broaching, the broach is disposed in the axially front region of the shaft portion, and the grooves of the pair of vertical wall portions A first cutting edge that protrudes toward the intermediate portion in the depth direction and cuts the intermediate portion in the depth direction of the groove toward the machining allowance direction that is the groove width direction; and an axial rear side region of the shaft portion. And the workpiece by the first cutting edge A second cutting edge having a workpiece cutting area set smaller than the workpiece cutting area, and the second cutting edge extends the vertical wall portion of the concave groove from an intermediate portion in the groove depth direction of the concave groove. Cutting along the cutting width direction along the curvature of the pair of vertical wall portions toward the groove depth direction distal end portion and the groove depth direction proximal end portion, respectively .

In the broach according to the invention described in claim 5, a plurality of cutting blades are arranged on the long shaft portion along the axial direction of the shaft portion, and only the front end portion of the shaft portion is clamped, and the cross section is Axial direction along the axial direction of the shaft portion relative to the workpiece formed with a concave groove having a pair of vertical wall portions curved in a convex shape and a bottom wall portion connecting the tip portions of the vertical wall portions. In the broach for cutting the workpiece by the cutting blades by moving to the front side and subjecting the workpiece to broaching, the broach is disposed in the axially front region of the shaft portion, and the grooves of the pair of vertical wall portions Projecting toward the depth direction proximal end portion and the groove depth direction distal end portion, and cutting the groove depth direction proximal end portion and the groove depth direction distal end portion toward the machining allowance direction, which is the groove width direction, respectively. a first cutting edge that, after the axial direction of the shaft portion A second cutting edge that is disposed in the region and has a workpiece cutting area set smaller than a workpiece cutting area of the workpiece by the first cutting edge, and the second cutting edge includes: Cutting width direction along the curvature of the pair of vertical wall portions from the groove depth direction proximal end portion and the groove depth direction distal end portion to the groove depth direction intermediate portion of the vertical wall portion of the groove It is characterized by cutting along .

According to the invention described in claim 1, to reduce the cutting area of the second cutting edge front and rear ends are arranged in parts position deflection amount of the shank ing large when clamped by the second to reduce the cutting load acting on the cutting edge, increasing the cutting load acting on the first cutting edge disposed on part position deflection amount of the shaft portion may turn smaller Te, a front end second small back component force acting on the cutting edge, the deflection amount is small and that portion of the shaft portion which the rear end portion are arranged in parts position deflection amount of the shank ing large when clamped It is possible to increase the back component force acting on the first cutting edge disposed at the position.

  Therefore, the bending of the broach at the time of broaching can be suppressed, and the maximum amount of bending of the shaft portion can be reduced. And it can prevent that an impact is applied to each cutting edge due to the bending of a broach, and can suppress the generation | occurrence | production and progress of abnormal wear, such as chipping, and can extend the tool life of a broach.

According to the second aspect of the present invention, when the front end portion and the rear end portion of the broach are clamped and moved toward the front side in the axial direction of the broach, the shaft portion, which is a portion where the amount of bending of the shaft portion is reduced, is reduced. The first cutting edge disposed in the front area in the axial direction has a groove depth direction proximal end portion and a groove depth direction distal end portion of the vertical wall portion of the recessed groove provided in the workpiece toward the machining allowance direction. The second cutting edge disposed in the axial central region of the shaft portion, which is a portion where the amount of bending of the shaft portion is increased, cuts the vertical wall portion of the recessed groove formed in the workpiece into the groove of the groove. Cutting is performed along the cutting width direction from the distal end portion in the depth direction and the proximal end portion in the groove depth direction toward the intermediate portion in the groove depth direction.

Thereby, the work cutting area of the second cutting edge disposed in the axial central region can be reduced, and the work cutting area of the first cutting blade disposed in the axial front region can be increased, The back component force acting on the second cutting edge disposed in the central region in the axial direction can be reduced, and the back component force generated by the first cutting blade disposed in the front region in the axial direction can be increased.

  Therefore, the bending of the broach at the time of broaching can be suppressed, and the maximum amount of bending of the shaft portion can be reduced. And it can prevent that an impact is applied to each cutting edge due to the bending of a broach, and can suppress the generation | occurrence | production and progress of abnormal wear, such as chipping, and can extend the tool life of a broach.

According to the invention described in claim 3, when the front end portion and the rear end portion of the broach are clamped and moved toward the front side in the axial direction of the broach, the shaft portion which is a portion where the amount of bending of the shaft portion becomes small The third cutting edge disposed in the axial rear side region has a shape that cuts the vertical wall portion of the concave groove provided in the workpiece in the machining allowance direction over the groove depth direction. Yes.

Thus, by clamping the front and rear ends of the broach when moving toward the axial front side of the broach, the third cutting edge disposed on part position deflection amount of the shaft portion may turn smaller by increasing the workpiece cutting area, the second to reduce the back component force acting on the cutting edge, part position deflection amount of the shaft portion may turn smaller disposed section position deflection amount of the shank ing large It is possible to increase the back component force acting on the third cutting edge disposed in the.

  Therefore, the bending of the broach during the broaching process can be suppressed, and the maximum amount of bending of the shaft portion can be reduced. Therefore, it is possible to prevent an impact from being applied to each cutting edge due to the bending of the broach, and to suppress the occurrence and progress of abnormal wear such as chipping of each cutting edge, thereby extending the tool life of the broach.

According to the fourth aspect of the present invention, the second cutting edge is reduced by reducing the cutting area by the second cutting edge disposed at the portion where the amount of deflection of the shaft portion when only the front end portion is clamped is increased. The front end portion and the rear end portion were clamped by reducing the cutting load acting on the blade and increasing the cutting load acting on the first cutting blade disposed in the portion where the amount of deflection of the shaft portion is small. The first cutting edge disposed at the portion where the amount of bending of the shaft portion is reduced by reducing the back force acting on the second cutting blade disposed at the portion where the amount of bending of the shaft portion increases. The back force acting on can be increased.

  Therefore, the bending of the broach during the broaching process can be suppressed, and the maximum amount of bending of the shaft portion can be reduced. Therefore, it is possible to prevent an impact from being applied to each cutting edge due to the bending of the broach, and to suppress the occurrence and progress of abnormal wear such as chipping of each cutting edge, thereby extending the tool life of the broach.

According to the invention described in claim 5, when only the front end portion of the broach is clamped and moved toward the front side in the axial direction of the broach, the front side in the axial direction of the shaft portion which is a portion where the amount of deflection of the shaft portion becomes small. The first cutting edge disposed in the region cuts the groove depth direction proximal end portion and the groove depth direction distal end portion of the vertical wall portion of the recessed groove provided in the workpiece toward the take-off direction, The second cutting edge disposed in the axial rear side region of the shaft portion, which is a portion where the amount of bending of the shaft portion is large, has a groove depth of the groove in the vertical wall portion of the groove formed in the workpiece. Cutting is performed along the cutting width direction from the direction tip portion and the groove depth direction base end portion toward the groove depth direction intermediate portion. As a result, the work cutting area of the cutting edge disposed in the axial rear region can be reduced, and the work cutting area of the cutting blade disposed in the axial front region can be increased. It is possible to reduce the back component force acting on the cutting blade disposed on the front and to increase the back component force due to the cutting blade disposed in the axial front side region.

  Therefore, the bending of the broach during the broaching process can be suppressed, and the maximum amount of bending of the shaft portion can be reduced. Therefore, it is possible to prevent an impact from being applied to each cutting edge due to the bending of the broach, and to suppress the occurrence and progress of abnormal wear such as chipping of each cutting edge, thereby extending the tool life of the broach.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a broach showing the present embodiment, FIG. 2 is a longitudinal sectional view of a cutting edge K, and FIG. 3 is a view showing the shape of a workpiece before and after broaching. FIG. 3A is an overall view, and FIG. 3B is an enlarged view of a portion X in FIG. 3A. A broken line in the drawing indicates the shape of the groove after broaching.

  The broach 1 has a long round bar shape, and as shown in FIG. 1, the front grip part (front end part) 2, the front guide part 3, the cutting blade part 4, the rear part in order from the front side in the axial direction. A guide portion 5 and a rear grip portion (rear end portion) 6 are formed. Then, the front grip part 2 and the rear grip part 6 are clamped by a broaching apparatus (not shown) and moved so as to be pulled out at a predetermined speed and a predetermined tensile force toward the front side in the axial direction, which is the cutting direction. The machining conditions are set so that the workpiece 100 (see FIG. 3) is broached.

  The cutting blade portion 4 is made of an ultrafine particle cemented carbide and is coated with a hard coating. As the ultrafine particle cemented carbide, for example, a WC fine powder having a particle diameter of 1 μm or less sintered with Co of 12% or less as a binder is used. For the hard coating, for example, (TiAl) N having an oxidation start temperature of 800 ° C. or higher is used.

  In the cutting blade portion 4, a plurality of cutting edges K are arranged so as to form a plurality of rows in the circumferential direction and a plurality of stages in the axial direction, and by performing broaching on the workpiece 100, FIG. As shown in FIG. 3 (b), a pair of R wall portions (vertical wall portions) 102 whose sections are curved in a convex shape with a predetermined radius of curvature and the bottoms connecting the tip portions of the pair of R wall portions 102 in a straight line A plurality of concave grooves 104 having a wall portion 103 are formed on the inner peripheral surface of the center hole 101 at a predetermined interval in the circumferential direction.

  Each cutting edge K is formed by making the finishing allowance larger than 60 μm and completely removing the heat treatment distortion caused by the heat treatment of the cutting edge K itself, and projecting radially from the outer peripheral surface of the shaft portion 11. And has a convex shape extending in the axial direction. As shown in FIG. 2, the rake face 20 is formed on the front side in the axial direction, the flank face 30 is formed along the axial direction, and the edge portion 40 is formed by the ridge line portion between the rake face 20 and the flank face 30. ing.

  The rake face 20 gradually moves to the rear side in the axial direction as it moves in the direction orthogonal to the axial direction of the broach 1 and from the radial center side of the broach 1 toward the radially outer side, and is orthogonal to the axial center of the broach 1. It has a surface shape inclined by a rake angle α with respect to the direction.

  As shown in FIG. 2, the flank 30 is inclined so as to gradually move toward the axial center of the broach 1 as it moves from the front side in the axial direction toward the rear side. The clearance angle β is formed between them. If the clearance angle β is 0.5 ° or less, the machined surface roughness deteriorates and scoring occurs, and if it is 1 ° or less, abrasion due to rubbing occurs and the tool life is reduced. It is set in the range of 1 ° to 5 ° without having a clearance angle of 0 °.

  When the cutting depth is less than 5 μm when the workpiece of the hardened material of HRC50 to HRC65 is finished and cut, if the cutting depth is less than 5 μm, the burden of the next cutting edge K + 1 that continues to the cutting edge K becomes excessive, and chipping On the other hand, if the depth of cut exceeds 15 μm, the cutting load will increase significantly, the cutting temperature will rise, chipping will occur and the tool life will be reduced, and as the cutting temperature increases Is set in the range of 5 μm to 15 μm because the previous temperature rises and wear becomes severe and the cutting efficiency decreases.

  As shown in FIG. 1, each cutting edge K of the cutting blade portion 4 is formed into a rough cutting blade group P, a medium rough cutting blade group Q, a medium finishing blade group R, and a final finishing blade group S in order from the front side in the axial direction. I know.

  Each cutting edge Kp forming the rough cutting blade group P is for rough cutting to remove heat treatment distortion of the workpiece 100 formed by the heat-treated quenching material, and is more axial than the axial central region of the broach 1. A plurality of axially-front-side regions located on the front side are provided at predetermined intervals in the axial direction. Then, as the cutting edge Kp on the front side in the axial direction shifts to the cutting edge Kp on the rear side in the axial direction, the intermediate portion of the R wall portion 102 of the R wall portion 102 of the concave groove 104 of the workpiece 100 gradually increases in diameter. It is formed so as to cut in the machining allowance direction which is the direction (groove width direction of the concave groove 104).

  FIG. 4 is an axial arrow view for explaining the shape of each cutting edge Kp forming the rough cutting blade group P of the broach 1 in the first embodiment. 4 indicates the nth cutting edge from the front side in the axial direction of the rough cutting blade group P, Kpn + 1 indicates the (n + 1) th cutting edge located on the rear side in the axial direction of the cutting edge Kpn, and Kpn + 2 indicates the cutting edge. The (n + 2) th cutting edge located on the rear side in the axial direction of the blade Kpn + 1 is shown. FIG. 5 is a diagram showing a cutting state of the workpiece 100 by the cutting edges Kpn to Kpn + 2 of the rough cutting blade group P.

  As shown in FIGS. 4 and 5A to 5C, each cutting edge Kp of the rough cutting blade group P shifts from the cutting edge Kp on the front side in the axial direction to the cutting edge Kp on the rear side in the axial direction. Accordingly, the intermediate portion of the R wall portion 102 of the concave wall 104 of the workpiece 100 is formed so as to be cut in the cutting direction.

  The flank 31 of the cutting edge Kp rises in parallel with each other from the outer peripheral surface of the shaft part 11 and faces a pair of side surface parts 31a and 31a facing the groove depth direction base end part of the R wall part 102, and a pair of A chamfer is formed between the side surface 31a and the top surface portion 31b between the top surface portion 31a and the top surface portion 31b of the R wall portion 102 connected to the top of the groove wall in the groove depth direction and the bottom wall portion 103. And a curved surface portion 31c.

  Edge portions 41a, 41b, and 41c are formed at each ridge portion between the rake face 21 and the side face portion 31a, between the rake face 21 and the upper face portion 31b, and between the rake face 21 and the curved face portion 31c. Has been.

  The curved surface portion 31c is formed so that the edge portion 41c is convexly curved with a curvature similar to that of the R wall portion 102, and the cutting edge positioned on the axially rear side from the cutting edge Kp positioned on the axially front side. It is formed so as to move toward the radially outer side of R wall 102 (in the direction of arrow T1 in FIG. 4) as it shifts to Kp.

  Therefore, in the rough cutting blade group P, the groove depth direction intermediate portion of the R wall portion 102 of the concave groove 104 of the workpiece 100 is gradually changed to R in accordance with the transition from the axial front cutting edge Kp to the axial rear rear cutting edge Kp. The wall 104 can be cut in the machining allowance direction, which is the diameter expansion direction.

  FIG. 10 is an axial arrow view for explaining the shape of each cutting edge Kp forming the rough cutting blade group P of the broach 1 in the second embodiment. Kpn shown in FIG. 10 indicates the nth cutting edge from the front side in the axial direction of the rough cutting blade group P, Kpn + 1 indicates the (n + 1) th cutting edge located on the rear side in the axial direction of the cutting edge Kpn, and Kpn + 2 indicates the cutting edge. The (n + 2) th cutting edge located on the rear side in the axial direction of the blade Kpn + 1 is shown. FIG. 11 is a diagram showing a cutting state of the workpiece 100 by the cutting edges Kpn to Kpn + 2 of the rough cutting blade group P.

  As shown in FIGS. 10 and 11 (a) to 11 (c), each cutting edge Kp is gradually recessed as the cutting edge Kp of the workpiece 100 gradually changes from the cutting edge Kp on the front side in the axial direction to the cutting edge Kp on the rear side in the axial direction. A groove depth direction base end portion and a groove depth direction distal end portion of the R wall portion 102 included in the groove 104 are cut in a machining allowance direction that is a diameter expansion direction of the R wall portion 102 (a groove width direction of the concave groove 104). Is formed.

  The flank 35 of the cutting edge Kp rises in a pair from the outer peripheral surface of the shaft portion 11 and faces the lower curved surface portion 35a and the R wall portion 102 facing each other along the groove depth direction base end portion of the R wall portion 102. An intermediate connecting the lower curved surface portion 35a and the upper curved surface portion 35b with a predetermined gap between the upper curved surface portion 35b and the R wall portion 102 facing each other along the front end portion in the groove depth direction. The upper surface part 35d which connects between the top parts of the part 35c and a pair of upper curved surface part 35b, and opposes the bottom wall part 103 is provided.

  Each ridge line between the rake face 25 and the lower curved surface portion 35a, between the rake face 25 and the upper curved surface portion 35b, between the rake face 25 and the intermediate portion 35c, and between the rake face 25 and the upper surface portion 35d. Edge portions 45a, 45b, 45c, and 45d are formed in the portion.

  The lower curved surface portion 35 a and the upper curved surface portion 35 b are formed so that the edge portions 45 a and 45 b formed at the ridge line portion with the rake face 25 are curved in a convex shape with a curvature similar to the R wall portion 102. And it forms so that it may move toward the radial direction outer side (arrow T4 direction in FIG. 10) of R wall part 102 as it shifts from the cutting edge Kp located in the axial front side to the cutting edge Kp located in the axial rear side. Has been.

  Accordingly, in the rough cutting blade group P, the intermediate portion of the R wall portion 102 of the concave groove 104 of the workpiece 100 is gradually changed from the cutting edge Kp on the front side in the axial direction to the cutting blade Kp on the rear side in the axial direction. It can cut in the machining allowance direction which is the diameter expansion direction.

  A plurality of cutting edges Kq forming the medium rough cutting blade group Q are provided at predetermined intervals in the axial direction in the axial central region located in the axial center of the broach 1. Then, as the cutting edge Kq on the front side in the axial direction shifts to the cutting edge Kq on the rear side in the axial direction, the R wall portion 102 of the concave groove 104 of the workpiece 100 is gradually changed along the arc of the R wall portion 102 (the concave groove 104). Are formed so as to be cut in the cutting width direction (groove depth direction).

  FIG. 6 is an axial view illustrating the shape of each cutting edge Kq forming the medium rough cutting blade group Q of the broach 100 according to the first embodiment, and FIG. 7 is a view of each cutting edge Kq of the medium rough cutting blade group Q. FIG. 7A to FIG. 7C are diagrams showing the cutting state of the workpiece 100, in which the cutting edges Kq of the medium rough cutting blade group Q are arranged in order from the axial front side to the axial rear side. It is.

  As shown in FIGS. 6 and 7 (a) to 7 (c), each cutting edge Kq is gradually recessed as the cutting edge Kq of the workpiece 100 moves from the axial front cutting edge Kq to the axial rear cutting edge Kq. The groove 104 is formed so as to cut an intermediate portion in the groove depth direction of the R wall portion 102 of the groove 104 in the cutting width direction.

  The flank 32 of the cutting edge Kq rises in parallel with each other from the outer peripheral surface of the shaft portion 11, and a pair of side surfaces 32 a, 32 a that face the groove depth direction base end portion of the R wall portion 102, 32a, an upper surface portion 32b that is connected between the tops of the 32a and is opposed to the bottom wall portion 103 with a predetermined gap, and a curved surface portion that is chamfered between the side surface portion 32a and the upper surface portion 32b. 32c.

  The side portions 32a and 32a are separated from each other as the edge portions 42a and 42a formed at the ridge line portion with the rake face 22 move from the cutting edge Kq positioned on the axial front side to the cutting edge Kq positioned on the axial rear side. It is formed so as to move in the direction (arrow H1 direction in FIG. 6).

  The upper surface portion 32b is formed so that the edge portions 42b and 42b formed at the ridge line portion with the rake face 22 move from the cutting edge Kq positioned on the front side in the axial direction to the cutting edge Kq positioned on the rear side in the axial direction. It is formed so as to move radially outward (in the direction of arrow H2 in FIG. 6).

  The curved surface portion 32c is positioned on the rear side in the axial direction from the cutting edge Kq located on the front side in the axial direction, with the edge portion 42c formed on the ridge line portion with the rake face 22 curved in a convex shape along the R wall portion 102. It is formed so as to expand in the cutting width direction as it shifts to the cutting edge Kq.

  Accordingly, in the middle rough cutting blade group Q, the intermediate portion in the groove depth direction of the R wall portion 102 of the concave groove 104 of the workpiece 100 is gradually changed from the axial front cutting edge Kq to the axial rear rear cutting edge Kq. Cutting can be made in the cutting width direction, which is the direction along the arc of the R wall 102.

  FIG. 12 is an axial view illustrating the shape of the cutting edge Kq that forms the medium rough cutting blade group Q of the broach 1 in the second embodiment, and FIG. 13 is a view of each cutting edge Kq of the medium rough cutting blade group Q. FIG. 13A to FIG. 13C are diagrams showing the cutting state of the workpiece 100, in which the cutting edges Kq of the medium rough cutting blade group Q are arranged in order from the axial front side to the axial rear side. It is.

  As shown in FIGS. 12 and 13 (a) to 13 (c), each cutting edge Kq is gradually recessed in the workpiece 100 as it shifts from the axial front cutting edge Kq to the axial rear cutting edge Kq. A groove depth direction base end portion and a groove depth direction distal end portion of the R wall portion 102 of the groove 104 are formed so as to be cut in the cutting width direction and in a direction approaching each other.

  The flank 36 of the cutting edge Kq rises in a pair from the outer peripheral surface of the shaft portion 11, and faces the lower curved surface portion 36 a and the R wall portion 102 facing each other along the groove depth direction base end portion of the R wall portion 102. An intermediate surface that is interposed between the upper curved surface portion 36b, the lower curved surface portion 36a, and the upper curved surface portion 36b that face each other along the front end portion in the groove depth direction and that has a predetermined gap with the R wall portion 102. The upper surface portion 36d is connected between the top portions of the upper curved surface portions 36b and is opposed to the bottom wall portion 103, and extends substantially parallel to the upper surface portion 36d between the lower curved surface portion 36a and the intermediate portion 36c. Between the lower stepped portion 36e, the upper curved surface portion 36b and the intermediate portion 36c, there is an upper stepped portion 36f extending along a direction substantially orthogonal to the upper surface portion 36d.

  And between the lower curved surface portion 36a and the rake surface 26, between the upper curved surface portion 36b and the rake surface 26, between the intermediate portion 36c and the rake surface 26, between the lower step portion 36e and the rake surface 26, and above Edge portions 46a, 46b, 46c, 46d, 46e, and 46f are formed at the ridge line portion between the stepped portion 36f and the rake face 26.

  The lower curved surface portion 36a and the upper curved surface portion 36b approach each other along the cutting width direction as the cutting edge Kq positioned on the axially front side shifts to the cutting edge Kq positioned on the axially rear side (arrow in FIG. 12). The edge portion 46a and the edge portion 46b approach each other along the arc of the R wall portion 102 and move in the direction of gradually narrowing the intermediate portion 36c.

  Accordingly, in the middle rough cutting blade group Q, the intermediate portion in the groove depth direction of the R wall portion 102 of the concave groove 104 of the workpiece 100 is gradually changed from the axial front cutting edge Kq to the axial rear rear cutting edge Kq. Cutting can be made in the cutting width direction, which is the direction along the arc of the R wall 102.

  A plurality of cutting edges Kr forming the intermediate finishing blade group R are provided at predetermined intervals in the axial direction in an axial rear side region located on the axial rear side of the axial direction central region of the broach 1. . Then, as the cutting edge Kr on the front side in the axial direction shifts to the cutting edge Kr on the rear side in the axial direction, the R wall portion 102 of the concave groove 104 of the workpiece 100 is gradually changed in the diameter increasing direction of the R wall portion 102 (the groove of the concave groove 104). It is formed so as to cut in the machining allowance direction (width direction).

  FIG. 8 is an axial view for explaining the shape of the cutting edge Kr forming the intermediate finishing blade group R of the broach 1 in the first embodiment, and FIG. 9 is a workpiece 100 by each cutting edge Kr of the intermediate finishing blade group R. 9 (a) to 9 (c) show the cutting edges Kr of the intermediate finishing blade group R arranged in order from the front side in the axial direction to the rear side in the axial direction.

  14 is an axial view for explaining the shape of the cutting edge Kr that forms the intermediate finishing blade group R of the broach 1 in the second embodiment, and FIG. 15 is a view of each cutting edge Kr of the intermediate finishing blade group R. FIG. 15A to FIG. 15C are diagrams showing the cutting state of the workpiece 100, in which the cutting edges Kr of the intermediate finishing blade group R are arranged in order from the axial front side to the axial rear side. is there.

  As shown in FIGS. 8, 9, 14, and 15, each cutting edge Kr has a concave groove 104 of the workpiece 100 that gradually moves from the axial front cutting edge Kr to the axial rear rear cutting edge Kr. The R wall portion 102 is formed so as to be cut in the machining allowance direction over the entire length along the arc of the R wall portion 102.

  The flank 33 of the cutting edge Kr is opposed to the bottom wall 103 by connecting a pair of curved surfaces 33a rising in pairs from the outer peripheral surface of the shaft 11 and the tops of the pair of curved surfaces 33a. A flat upper surface portion 33b, and edge portions 43a and 43b are formed at ridge portions between the curved surface portion 33a and the rake surface 23 and between the upper surface portion 33b and the rake surface 23. Yes.

  The curved surface portion 33 a is formed such that an edge portion 43 a formed at a ridge line portion with the rake face 23 is curved in a convex shape with a curvature similar to the R wall portion 102. Then, as the cutting edge Kr positioned on the front side in the axial direction shifts to the cutting edge Kr positioned on the rear side in the axial direction, the R wall portion moves in a direction away from each other (in the direction of arrow T3 in FIGS. 8 and 14). It is formed so as to move in the diameter expansion direction of 102.

  Accordingly, in the intermediate finishing blade group R, the R wall portion 102 of the concave groove 104 of the workpiece 100 gradually extends along the arc of the R wall portion 102 as the axial cutting edge Kr shifts from the axial front cutting edge Kr to the axial rear rear cutting edge Kr. It can cut into the machining allowance direction which is the diameter expansion direction of the R wall 102 over the entire length.

  The cutting edge Ks of the final finishing blade group S finally determines the machining dimension of the workpiece 100, and is in the axial rearmost region located further on the axial rear side than the axial rear side region of the broach 1. A plurality of them are provided at predetermined intervals in the axial direction. The variation amount in the cutting direction with respect to the cutting edge Ks on the front side in the axial direction is set to be within 0 μm to 4 μm.

  In broaching the workpiece 100 using the broach 1 having the above-described configuration, first, the workpiece 100 is fixed to a broaching machine (not shown). Then, the front gripping part 2 of the broach 1 is inserted into the center hole 101 previously drilled in the workpiece 100 and clamped to the clamping part of the broaching machine, and the rear gripping part 6 of the broach is supported at the rear end of the broaching machine. Support the part.

  Then, the broaching machine is operated to move the clamp portion toward the front side in the axial direction that is the cutting direction of the broach 1 with a predetermined moving speed and load, and the rear end support portion that supports the rear grip portion 6 is moved. The broach 1 is moved toward the front side in the axial direction in synchronization with the clamp portion.

  In the workpiece 100, the R wall portion 102 is cut by the cutting blades K of the rough cutting blade group P, the medium rough cutting blade group Q, the intermediate finishing blade group R, and the final finishing blade group S by the movement of the broach 1. A concave groove 104 having a dimensional shape is formed.

  Under the above processing conditions, the amount of bending of the broach 1 gradually increases as it moves from the front side in the axial direction of the broach 1 to the center in the axial direction, and gradually decreases as it moves from the center in the axial direction to the rear side in the axial direction. It is predicted that the amount of deflection in the central region in the axial direction is the largest. The following expression (1) is an expression indicating the maximum amount of deflection δmax generated in the broach 1 in accordance with the above processing conditions.

δmax = (WL ³ ) / (192EI) (1)
(W: Back component force, L: Axial length, E: Longitudinal elastic modulus, I: Cross section secondary moment)
The cutting load of the broach 1 is proportional to the cutting area (cutting width h × cutting amount t) of the cutting edge K. If the cutting area is large, the cutting load is large, and if the cutting area is small, the cutting load is small. Become.

  Further, in the broach 1, the cutting area of the workpiece 100 by each cutting edge K is adjusted according to the axial position of the shaft portion 11. Specifically, each cutting edge Kq of the medium rough cutting blade group Q formed in the axial central region of the broach 1 moves from the axial front cutting edge Kq to the axial rear rear cutting edge Kq. The R wall portion 102 of the concave groove 104 of the workpiece 100 is formed so as to be cut in a cutting width direction that is a direction along the arc of the R wall portion 102 (groove depth direction).

  On the other hand, each cutting edge Kp of the rough cutting blade group P formed in the axial front side region of the broach 1 and each cutting edge Kr of the intermediate finishing blade group R formed in the axial rear side region are in the axial direction. As the cutting edge Kp, Kr on the front side shifts to the cutting edge Kp, Kr on the rear side in the axial direction, the R wall portion 102 of the concave groove 104 of the workpiece 100 is gradually increased in the diameter increasing direction (groove width direction) of the R wall portion 102. It is formed so as to cut in a certain machining allowance direction.

  Therefore, the cutting area of the workpiece 100 in the axial center region of the broach 1 can be made smaller than the cutting area of the workpiece 100 in the axial front region and the axial rear region, and acts on the axial central region of the broach 1. The cutting load to be performed can be made smaller than the axial front side region and the axial rear side region of the broach 1. Thereby, the back force acting on the axial center region of the broach 1 can be reduced, and the back force acting on the axial front region and the axial rear region can be increased.

  Therefore, it is possible to positively reduce the maximum deflection amount δmax of the shaft portion 11 by suppressing the deflection of the broach 1 predicted based on the above processing conditions, and chipping each cutting edge K due to the deflection of the broach 1. The tool life of the broach 1 can be extended.

  FIG. 16 is a graph showing changes in cutting load when broaching is performed on the workpiece 100 made of a hardened material equivalent to HRC50 to HRC65, and FIG. 17 is a graph showing experimental results of tool life of the broach. is there.

  16 and 17, the workpiece 100 is broached by a front grip method using a conventional broach 200 in which each cutting edge expands in a similar manner as it moves from the axial front side to the axial rear side. The present invention shown in FIGS. 16 and 17 is data when the work 100 is broached by the double gripping method using the broach 1 in the present embodiment.

  The cutting load acting on the conventional broach changes so as to gradually increase as it shifts from the front side in the axial direction to the rear side in the axial direction, as indicated by a broken line in FIG. Therefore, in the front gripping method, the back component force W acting on the broach 200 increases as it shifts to the rear side in the axial direction where the amount of bending of the broach 200 increases. As a result, there is a concern that the broach 200 is greatly deflected, an impact is applied to the cutting edge 210, and abnormal wear such as chipping occurs.

  On the other hand, the cutting load acting on the broach 1 of the present invention has a large value in the axial front region and the axial rear region of the broach 1 and a small value in the axial central region as shown by the solid line in FIG. It changes to become.

  Accordingly, the back component force W acting on the central region in the axial direction of the broach 1 that is predicted to produce the maximum amount of deflection δmax based on the above processing conditions is smaller than those in the axial front region and the axial rear region. It is possible to suppress the bending of the broach 1 and positively reduce the maximum bending amount. Thereby, the application of the impact to the cutting edge K due to the bending of the broach 1 can be prevented, the occurrence and progress of abnormal wear such as chipping can be suppressed, and the tool life of the broach 1 can be extended as compared with the prior art.

  According to the experimental results shown in FIG. 17, the tool life of the conventional broach 200 is about 150 m in total cutting length, whereas the tool life of the broach 1 of the present invention is about 270 m in total cutting length. It can be seen that the tool life has increased to nearly twice.

  Moreover, when the said structure is applied to a cemented carbide broach, the finishing process of the hardening material equivalent to workpiece | work hardness HRC50-HRC65 can be given with high precision and low cost. Further, the finishing allowance can be 150 μm or more, and the heat treatment distortion can be completely removed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the case where the processing condition is the double gripping method has been described as an example, but the present invention can also be applied to the case where the processing condition is the front gripping method.

  When the processing condition is the front gripping method, it is predicted that the broach 1 bends so that the amount of bending increases as it moves to the rear side in the axial direction of the broach 1. Accordingly, the shape of the cutting edge is set so that, for example, the cutting direction of the cutting edge K gradually changes from the cutting allowance direction to the cutting width direction so that the cutting load decreases as the broach 1 moves from the axial front side to the axial rear side. May be changed.

It is a side view of the broach which shows this Embodiment. It is a longitudinal cross-sectional view of a cutting blade. It is a figure which shows the shape of the workpiece | work before broaching and after broaching. It is an axial direction arrow directional view explaining the shape of each cutting edge which forms the rough cutting blade group of the broach in Example 1. FIG. It is a figure which shows the cutting state of the workpiece | work by each cutting edge of the rough cutting blade group of the broach in Example 1. FIG. It is an axial direction arrow view explaining the shape of each cutting edge which forms the medium rough cutting blade group of the broach in Example 1. FIG. It is a figure which shows the cutting state of the workpiece | work by each cutting edge of the medium rough cutting blade group of the broach in Example 1. FIG. It is an axial direction arrow directional view explaining the shape of the cutting blade which forms the medium finishing blade group of the broach in Example 1. FIG. It is a figure which shows the cutting state of the workpiece | work by each cutting edge of the medium finishing blade group of the broach in Example 1. FIG. It is an axial direction arrow line view which shows the shape of the cutting blade which forms the rough cutting blade group of the broach in Example 2. FIG. It is a figure which shows the cutting state of the workpiece | work by each cutting edge of the rough cutting blade group of the broach in Example 2. FIG. It is an axial direction arrow line view explaining the shape of each cutting edge which forms the medium rough cutting blade group of the broach in Example 2. FIG. It is a figure which shows the cutting state of the workpiece | work by each cutting edge of the medium rough cutting blade group of the broach in Example 2. FIG. It is an axial direction arrow directional view explaining the shape of the cutting edge which forms the medium finishing blade group of the broach in Example 2. FIG. It is a figure which shows the cutting state of the workpiece | work by each cutting edge of the broaching medium finishing blade group in Example 2. FIG. It is the graph which showed the change of the cutting load at the time of giving a broach process to the workpiece | work consisting of the hardening material equivalent to HRC50-HRC65. It is a graph which shows the experimental result of the tool life of a broach. It is a figure explaining the cutting load which acts on a broach. It is a figure explaining the bending which arises in a broach.

Explanation of symbols

1 Brooch 2 Front grip (front end)
6 Rear grip (rear end)
11 Shaft part 20, 21, 22, 23, 25, 26 Rake face 30, 31, 32, 33, 35, 36 Flank 40, 41c, 42c, 43a, 45a, 45b, 46e, 46f Edge part 100 Workpiece 101 center Hole 102 R wall (vertical wall)
103 bottom wall 104 concave groove K cutting edge P rough cutting blade group Q medium roughing blade R medium finishing blade group S final finishing blade group

Claims (5)

Are front and rear ends are clamped elongated plurality of cutting edges to the axis of the are arranged along the axial direction of the shaft portion Rutotomoni the shaft portion, a pair of vertical cross section is curved in a convex shape By moving the wall portion and the front wall in the axial direction along the axial direction of the shaft portion relative to the work in which the concave groove having the bottom wall portion connecting the tip portion of the vertical wall portion is formed, In a broach that cuts the workpiece with a cutting edge and performs broaching on the workpiece,
The axial direction front side region of the shaft portion, and projects toward the intermediate portion in the groove depth direction of the pair of vertical wall portions, and the intermediate portion in the groove depth direction is the machining allowance direction that is the groove width direction, respectively. A first cutting edge that cuts toward
A second cutting edge that is disposed in an axial central region of the shaft portion and has a cutting area set smaller than a work cutting area of the workpiece by the first cutting edge;
The second cutting edge includes the pair of vertical walls extending from the middle portion in the groove depth direction of the groove toward the distal end portion in the groove depth direction and the proximal end portion in the groove depth direction. A broach that cuts along a cutting width direction along a curve of a wall portion . A plurality of cutting edges are arranged on the long shaft portion along the axial direction of the shaft portion, and a front end portion and a rear end portion of the shaft portion are clamped, and a pair of vertical curves whose sections are curved in a convex shape By moving the wall portion and the front wall in the axial direction along the axial direction of the shaft portion relative to the work in which the concave groove having the bottom wall portion connecting the tip portion of the vertical wall portion is formed, In a broach that cuts the workpiece with a cutting edge and performs broaching on the workpiece,
The groove depth direction base end is disposed in the axial front side region of the shaft portion and protrudes toward the groove depth direction proximal end portion and the groove depth direction distal end portion of the pair of vertical wall portions. A first cutting edge that cuts the portion and the tip portion in the groove depth direction toward the machining allowance direction that is the groove width direction, and
A second cutting edge that is disposed in a central region in the axial direction of the shaft portion and has a workpiece cutting area set smaller than a workpiece cutting area of the workpiece by the first cutting edge;
The second cutting edge includes the pair of vertical walls extending from the groove depth direction base end portion and the groove depth direction distal end portion of the groove toward the groove depth direction intermediate portion. A broach that cuts along a cutting width direction along a curve of a wall portion. A third cutting edge disposed in the axially rear region of the shaft portion;
The third cutting edge has a shape in which the vertical wall portion of the concave groove is cut in the machining allowance direction over the groove depth direction, and the work cutting area by the third cutting edge is the first cutting edge. The broach according to claim 1 or 2, wherein the broach is set to be larger than a workpiece cutting area by two cutting edges . A plurality of cutting blades are arranged in an elongated shaft portion in the axial direction of the shaft portion, and only a front end portion of the shaft portion is clamped, and a pair of vertical wall portions whose sections are curved in a convex shape, and By moving each axially forward along the axial direction of the shaft portion relative to the workpiece formed with a concave groove having a bottom wall portion connecting the tip portions of the vertical wall portions, In a broach that cuts the workpiece and performs broaching on the workpiece,
The axial direction front side region of the shaft portion, and projects toward the intermediate portion in the groove depth direction of the pair of vertical wall portions, and the intermediate portion in the groove depth direction is the machining allowance direction that is the groove width direction, respectively. A first cutting edge that cuts toward
A second cutting edge that is disposed in an axial rear side region of the shaft portion and has a workpiece cutting area set smaller than a workpiece cutting area of the workpiece by the first cutting edge;
The second cutting edge includes the pair of vertical walls extending from the middle portion in the groove depth direction of the groove toward the distal end portion in the groove depth direction and the proximal end portion in the groove depth direction. A broach that cuts along a cutting width direction along a curve of a wall portion. A plurality of cutting edges are arranged on the long shaft portion along the axial direction of the shaft portion, and only a front end portion of the shaft portion is clamped, and a pair of vertical wall portions whose cross section is curved in a convex shape, and By moving each axially forward along the axial direction of the shaft portion relative to the workpiece formed with a concave groove having a bottom wall portion connecting the tip portions of the vertical wall portions, In a broach that cuts the workpiece and performs broaching on the workpiece,
The groove depth direction base end is disposed in the axial front side region of the shaft portion and protrudes toward the groove depth direction proximal end portion and the groove depth direction distal end portion of the pair of vertical wall portions. A first cutting edge that cuts the portion and the tip portion in the groove depth direction toward the machining allowance direction that is the groove width direction, and
A second cutting edge that is disposed in an axial rear side region of the shaft portion and has a workpiece cutting area set smaller than a workpiece cutting area of the workpiece by the first cutting edge;
The second cutting edge includes the pair of vertical walls extending from the groove depth direction base end portion and the groove depth direction distal end portion of the groove toward the groove depth direction intermediate portion. A broach that cuts along a cutting width direction along a curve of a wall portion.

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