JP4756677B2 - brooch - Google Patents

Description

The present invention sequentially cuts the outer surface or the inner surface of the workpiece or the groove provided along the outer surface or the inner surface with a plurality of cutting blades whose height in the blade height direction gradually increases in the axial direction, and has a predetermined shape. Further, the present invention relates to a broach suitable for processing a high hardness material.

Chips generated during broaching are generally wider than the width of the cutting edge, and thus contact the cut surface of the workpiece and damage the processed surface. Therefore, in order to prevent the chips from being rubbed or to be rubbed out easily, or the chips from the entire circumference like a round broach are ring-shaped and clogged into the blade groove to cause chipping. to prevent it made, and construction nick (notched) Araha, the upper surface of the middle specifications raised edge as a chip breaker. The nick shape includes a U-shaped nick, a V-shaped nick, a flat nick, and a chamfer nick. Also, the nicks on each blade are arranged not in the same position but in a staggered or two-blade manner. However, Nick's corner and back blades are subject to wear. Therefore, the corner portion of Nick is made obtuse or rounded (for example, Patent Document 1). Further, in Patent Document 2, the rough cutting edge has a rough cutting edge shape, the wave shape is shifted with respect to the front cutting edge in the cutting direction, and the shift amount is in the range of P / 6 to P / 3. Several intermediate blades for smoothing the cutting surface by the rough cutting blade are provided between the intermediate finishing blades. In other words, the nicks of the wave are regarded as nicks to divide the chips, prevent the corners from being worn, and increase the cutting amount of the cutting edges.
Japanese Utility Model Publication No. 63-193618 JP-A-6-315820

  However, in order to process the nicks as described above, a nicking wheel is prepared, and in order to shift the nick arrangement in a staggered manner, a nicking wheel with multiple shapes is used, It was necessary to process by shifting in the horizontal direction.

  Further, in the case of the wavy cutting edge as in Patent Document 2, the wavy shaped grinding wheel must be moved in the upward direction and shifted in the horizontal direction, which is difficult to control and difficult to machine. Therefore, there is a problem that it is difficult to obtain accuracy.

  Further, in the processing of a high hardness material of 35-60 HRC (the same applies to the Rockwell C hardness below), the cutting allowance is as small as several μm to several tens of μm, and the base material of the broach cutting edge is powder high speed tool steel, It is a material harder than a workpiece such as cemented carbide, and it has been difficult to ensure the accuracy of the cutting edge in a process involving a shift or the like.

  In particular, in a broach or the like for a shaft hole such as a ball groove or a spline, it is difficult to form a nick or wave shaped blade along the tooth profile and shift it with one grindstone. For this reason, it is necessary to prepare a grindstone for each of a plurality of tooth profile shapes and perform transfer processing, but there is a problem that the types of grindstones increase.

In view of the above-described problems, an object of the present invention is to provide a broach having a highly accurate cutting edge shape, avoiding a shift or the like as much as possible, in a broach capable of reliably cutting chips . It is another object of the present invention to provide a broach having a cutting edge with a shape that can reduce the types of grindstones and can be easily processed.

In the present invention, in a broach provided with a plurality of cutting edges in which the height of the cutting edge in the axial direction gradually increases in the axial direction, a plurality of shaped blades in which the shape of the cutting edge is a first predetermined shape, A plurality of cutting blades are alternately arranged, and the plurality of cutting blades include an outer cutting blade whose shape of the cutting edge is a second predetermined shape, and a concave cutting blade formed inside the outer cutting blade. The height in the blade length direction of the outer cutting edge of the cutting blade that is the Nth cutting edge is the height of the cutting edge of the shaped blade that is the N-1th cutting edge. greater than the direction of the height, and the height of the blade height direction of the lowest portion in the blade height direction of the concave cutting edge than the height of the blade height direction of the cutting edge of the shape cutter is the first N-1 th cutting edge is low, blade height direction height of the shaped blade is the (N + 1) th cutting edge, in the N-th cutting edge The height in the blade height direction of the outer cutting edge of the cutting blade is equal to or smaller than the height of the cutting blade of the shape blade that is the N-1th cutting blade, Is described above by providing a broach with an odd number of N ≧ 3 when the first cutting edge is a cutting edge and an even number of N ≧ 2 when the first cutting edge is a shaped blade. Solved the problem.

That is, the cutting blades corresponding to nicks and the like are not provided continuously, but are provided alternately with the predetermined shape blades. The outer side of the concave cutting edge portion remains with respect to the portion divided by the outer cutting edge portion outside the concave cutting edge. The remaining part is scraped off with a shape cutting edge. Since the height of the shape cutting edge in the blade height direction is the same as or smaller than the height of the outer cutting edge of the previous cutting blade in the blade height direction , the cutting amount is small or little, and chips are easily discharged. The next cutting blade is divided at the outer cutting edge portion outside the concave cutting edge, and the outside of the concave cutting blade portion remains, and the remaining portion is scraped off by the shape cutting blade. By repeating this, chips are easily discharged. Even if the concave cutting edge position is not a specific position, the chip dischargeability is good. Further, the position of the concave cutting edge may not be a specific position, but the same position is preferable in order to reduce the number of grindstones and the lateral shift. The cutting amount depends on the ratio between the concave cutting edge and the outer cutting edge. For example, when the cutting amount is made as uniform as possible and the cutting load is stabilized, the ratio is set appropriately, for example.

In manufacturing the broach, the processing of the shaped blade only needs to move the first predetermined shape of the grindstone in the blade length direction. In addition, the cutting blade may be processed by moving an overall shape grindstone in accordance with the second predetermined shape outer cutting edge and concave cutting edge in the blade length direction. Moreover, you may form a concave cutting edge every other piece using the general shape grindstone only of a shape blade, and the general shape grindstone which processes only a concave cutting blade part. In any case, machining can be performed only by movement in the direction of the blade height ( the height of the cutting blade gradually increases), and shift or the like can be reduced or unnecessary.

  Moreover, in the invention concerning Claim 2, it was set as the broach provided with the said shape blade more than two blades following the last blade of the said parting blade. That is, in order to obtain a predetermined finish shape, when the cutting blade is final, a cutting residue on the concave cutting blade portion side is generated, and thus a shaped blade corresponding to a conventional intermediate blade is provided after the final cutting blade. Since one piece of the shaped blade causes a cutting residue of the divided blade, two or more blades are preferably provided. Thereby, a predetermined shape can be obtained.

Further, according to the invention described in claim 3, and with the cutting blade of the final blade subsequently broach digits set the finishing edges group subsequent to said shape blade having blades provided. If the shape blade has the same shape as the finishing blade, it can be made a finishing blade by providing several blades. However, there are many cases where the cutting direction and the cutting shape are different in roughing, medium processing and finishing processing. In this case, a cutting edge for finishing is further required. Therefore, a finishing blade group is provided so that finishing can be performed after the shape is made.

Moreover, in invention of Claim 4, it was set as the broach by which the shape of the cutting blade of these some cutting blades is made the same. As described above, it is not necessary to change the shape position of the concave cutting edge, and processing can be performed only by controlling the blade height direction. Therefore, all the shape of the shape blade cutting edge were the same. Thereby, what is necessary is just to prepare two types of grindstones in the process of the cutting blade of a broach, and a shape blade.

Furthermore, in the invention according to claim 5, a broach having a shape of a portion excluding a corresponding portion of the concave cutting edge of the first predetermined shape and the second predetermined shape is the same shape. According to this, grinding stone molding etc. are also easy. Alternatively, the predetermined shape portion may be processed with one general shape grindstone, and only the concave cutting edge portion may be processed with another general shape grindstone. Furthermore , it is good to set it as the broach whose 1st predetermined shape is the finishing shape of a workpiece | work . Thereby, it is possible to make the cutting length short while facilitating the discharge of chips by the cutting blade.

In the present invention, a cutting blade corresponding to a nick or the like and a blade having a predetermined shape are alternately provided, and the height in the blade height direction of the outer cutting blade of the cutting blade which is the Nth cutting blade is Nth The height in the blade height direction of the portion that is larger than the height in the blade height direction of the cutting blade of the shape blade that is the first cutting blade and that is the lowest in the blade height direction of the concave cutting blade is the N-1th blade. The height in the blade height direction of the shape blade that is the (N + 1) th cutting blade is lower than the height in the blade height direction of the cutting blade of the shape blade that is the cutting blade of the N + 1. The height of the outer cutting edge of the blade is the same as or smaller than the height of the cutting edge, and is larger than the height of the cutting edge of the shape blade of the N-1th cutting edge. The cutting process is repeated so that the cutting with the blade and the cutting with the shape of the remaining concave cutting edge side are repeated. Rino (blade height direction height increases gradually) arranged alternately cutting blade and shape blade, and so as to as good cutting and discharge of the chips. As a result, when processing the cutting edge of broach, the processing of the shaped blade and the cutting blade can be performed only by moving the grinding wheel in the specified shape in the blade height direction, and shifting is unnecessary or simple, so high-precision cutting is possible. A broach having a blade shape can be provided. In addition, the processing is easy, the types of grindstones can be reduced, the cost is low, and the broach has high processing accuracy.

Further, in the invention according to claim 2, since two or more shaped blades are provided instead of the conventional intermediate blade after the final cutting blade to obtain a predetermined shape, there are few scratches due to the cutting blade or scratches. It became a broach with good machining accuracy. Furthermore, in the invention described in claim 3, since the finishing blade group is further provided, machining with high accuracy can be performed. In addition, ideal roughing or intermediate machining can be performed with the shape blade, so the degree of freedom of the initial shape of the finishing blade is increased, accuracy is ensured, and consequently the cutting edge length can be shortened. .

Further, in the invention according to the fourth aspect, since all the cutting blades of the dividing blade are made the same, it is sufficient to prepare two kinds of grindstones when processing the cutting blade of the broach. There is less effort and quality control is easier. Furthermore, in the invention according to claim 5, the shape of the portion excluding the corresponding portion of the first predetermined shape of the concave cutting edge is the same as the second predetermined shape, and it is easy to form a grindstone. Easy to process. Furthermore , a broach whose first predetermined shape is the same as the finished shape of the workpiece can be made with a short cutting length while facilitating the discharge of chips by the cutting blade. Processing is also possible.

  As described above, according to the broach of the present invention, it can be widely applied to broaching of various shapes and broaching of various materials. In addition, it is possible to accurately manufacture difficult-to-process broaches with cutting edges made of powdered high-speed tool steel or cemented carbide for finishing high-hardness materials. Became to provide. Therefore, the accuracy of the finishing process by broaching a high-hardness material workpiece of 35 to 55 HRC or even 60 HRC is improved. Needless to say, it is preferable to appropriately coat the cutting edge with a hard film such as TiN, TiCN, or TiAlN.

  The present invention can also be applied to surface processing and through-hole processing, but the finish of the surface and through-holes can be processed by conventional broaching and reamer processing, and the surface of high-hardness materials and through-holes can be processed by grinding. There are few benefits. On the other hand, according to the broach of the present invention, there is a great merit that the groove processing that is difficult to be processed by the conventional processing method and the groove processing of the high hardness material can be mass-produced with high accuracy and the production efficiency is high.

  A first embodiment of the present invention will be described with reference to the drawings. 1A is a side view of a flat keyway broach of the present invention, FIG. 1B is a front view of a blade portion, and FIG. 2 is a perspective view of a rough cutting blade and a shape blade (exaggerated for explanation). ). As shown in FIGS. 1 and 2, the flat keyway broach 1 is provided with a plurality of blade portions 3 having a blade width W of a machining groove dimension width on the surface of the main body 2 in the longitudinal direction. The main body 2 has a grip portion 11 and a front guide portion 12, and a rough blade 6, a semi-finished blade 5, and a finishing blade 4 are sequentially provided rearward (to the right in the drawing). The blade portion 3 includes a rake face 13, a flank face 14, a back face 15, a side face 16 of the blade, and the like, and cutting edges 7, 8, and 9 are formed by the rake face and the flank face. The cutting blades 7 and 8 are substantially linear, and the cutting blade 9 is composed of a linear cutting blade 9s of a shape blade 9a described later, an outer cutting blade 9c of a cutting blade 9b, and a concave cutting blade 9d. The side surface 16 is provided with a relief for avoiding contact with the side surface of the workpiece.

The cutting edge 7 of the finishing blade 4 is a straight line, the heights of the plurality of cutting edges are substantially the same size, and a straight line that is the final (finished) shape of the workpiece (workpiece) is processed. The cutting edge 8 of the intermediate finishing edge 5 has substantially the same shape as the cutting edge 7 of the finishing edge, and the cutting amount is set in the blade length direction.

As shown in FIG. 2, the cutting blade 9 of the rough blade 6 has a plurality of shape blades 9a and a plurality of cutting blades 9b arranged alternately with a straight cutting edge shape (first predetermined shape). ing. The plurality of cutting blades 9b are provided with an outer cutting blade 9c having a straight cutting edge (second predetermined shape) and a V-shaped concave cutting blade 9d formed inside the outer cutting blade. The first blade 9b (1) of the rough blade is a cutting blade, and the second blade 9a (2) is a shape blade. N is an odd number of N ≧ 3, and the height h (N) in the blade height direction of the outer cutting edge 9c (N) of the cutting edge 9b (N) which is the Nth cutting edge is N−1. The depth (height) Z of the concave cutting edge 9d (N) is larger than the height h (N-1) in the blade height direction of the cutting edge of the shaped blade 9a (N-1) which is the second cutting edge. N) is a shape that is deeper than the height h (N-1) in the blade height direction of the cutting edge of the shape blade 9a (N-1), which is the (N-1) th cutting edge, and is the (N + 1) th cutting edge. The blade 9a (N + 1) is smaller than the height in the blade height direction of the outer cutting edge 9c (N) of the cutting blade 9b (N), which is the Nth cutting blade, and is the (N-1) th cutting blade. It is made larger than the height in the blade length direction of the cutting edge of the shape blade 9a (N-1).

The final blade of the rough blade is a cutting blade, and further three shaped blades 9a are provided to form the previously described intermediate finish blade 5. Further, following the shape blade 9a as the intermediate finish blade 5, as described above, the finishing blade 4 group having the linear cutting blades 7 having the same height in the blade height direction is provided. The first predetermined shape of each cutting edge, the second predetermined shape excluding the concave cutting edge portion , and the finishing blade shape are the same shape of the straight blade.

Processing of the key groove using such a broach is performed as follows. FIG. 3 is an explanatory view of the cutting edge of the keyway machining (exaggerated for explanation). In FIG. 3, the roughing blade 6, the intermediate finishing blade 5, and the finishing blade 4 are passed through the workpiece 20 in which the front guide groove 21 indicated by the dotted line is processed by the front guide portion 12 of the broach 1, and the groove processing is performed. Do. In the processing of the rough blade 6, the first blades are the cutting blades 9 b (1) outer cutting blades 9 c (1) and 9 d (1), and the tip of the V-shaped concave cutting blade 9 d (1) is from the front guide groove 21. At a deeper position and leaving a central V-shaped portion (the tip 22a is missing), the workpiece 20 is cut into the upwardly inclined lines 22 and 22 cut and discharged. Next, the height of the cutting edge 9s (2), 9s (N-1) of the second blade 9a (2) or 9a (N-1) shaped blade in the blade height direction is the outside of the first blade 9b (1). Since the height of the cutting edge 9c (1) is smaller than the height in the blade height direction, the reference numeral 23 portion of the left upward oblique line, that is, the inverted trapezoidal portion at the V-shaped central portion is cut and discharged.

Next, the height in the blade length direction of the outer cutting edges 9c (3) and 9c (N) of the third cutting blade is the shape of the second cutting blade 9a (2) or 9a (N-1). Cutting edge 9s (2), which is larger than the height of cutting edge 9s (2), 9s (N-1) in the blade length direction, and has a V-shaped concave cutting edge 9d (3) or 9d (N). 2) or 9 s (N-1) shaped blade is cut into the workpiece 20 at a position where the tip is deeper than the height in the blade height direction , leaving a central V-shaped portion (tip portion 23b is missing). The reference numerals 24 and 24 of the stippled portion are cut and discharged. Furthermore, the height in the blade height direction of the cutting edges 9s (4) and 9s (N + 1) of the shape blade of the fourth blade is smaller than the height in the blade height direction of the outer cutting edge 9c (3) of the third blade. The portion 25 of the diagonal line rising to the right, that is, the inverted trapezoidal portion at the center of the V shape is cut and discharged. By repeating this, the grooves are sequentially cut to increase the blade height.

The final blades of the rough blade 6 are the cutting blades 9c (E) and 9d (E) of the cutting blade, and the portions 26 and 26 are cut and discharged. Subsequent to the final edge of the rough edge, the semifinished blade 5 having the same straight edge 8 as the shape edge 9a, the remaining trapezoidal portion 27, that is, the inverted trapezoidal shape of the V-shaped (25b portion is deleted) central portion The portion is cut and discharged, and the reference numerals 28, 28, and 28 are further cut and discharged, and the final (finished) shape 30 is finished by the cutting edge 7 of the finishing blade 4 to complete the keyway processing.

  As described above, according to the embodiment of the present invention, in rough edge machining, chips are divided, chip discharge performance is improved, and tool life is extended. The cutting edge of the broach uses a grindstone with a straight cross section and a grindstone with a V-shaped convex cross section alternately. When the height in the blade length direction is gradually increased, the grindstone is sequentially shifted upward (arrow direction). By doing so, it can be easily processed.

Although the final blade 9b (E) has N = 3 for the sake of simplicity of explanation, it goes without saying that the first blade is a shape blade, and N may be an even number of 2 or more . The number of rough blades 6, the intermediate finishing blade 5, and the finishing blade 4 and the machining allowance are set as appropriate. Similarly, the rake face 13, the flank face 14, the back face 15, the side face 16 of the blade, the land, and the like are shaped and dimensioned according to each blade portion. The connection point 18 between the outer cutting edge 9c and the concave cutting edge 9d may be a circular arc or the like, and the corners may be eliminated. Shape of the concave cutting edge is of course possible similar variety of forms and traditional. The workpiece may be a material that can be easily processed before quenching or a high-hardness material after quenching . In particular, it is preferable that the workpiece is applied in finishing of a hard material.

  Next, a second embodiment of the present invention will be described. The second embodiment shows an example in which the present invention is applied to finishing of a CVT ball groove that has been heat-treated as a workpiece and has a high hardness. FIG. 4 is a plan view of a high-hardness workpiece having a ball groove processed by the broach of the present invention, and FIG. 5A is a partial sectional side view of the broach tool of the present invention for finishing the ball groove (from the center line). The right side is a side view, the left side of the center line is a cross-sectional view), (b) is a cross-sectional view taken along the line AA of (a), FIG. The left side is omitted, and is exaggerated for the sake of explanation).

As shown in FIG. 4, the workpiece 50 is provided with ball grooves 51 having an R shape with a small radius of curvature in a petal shape along three through holes 50a. The R shape of the ball groove 51 is formed symmetrically with respect to a line segment passing through the through-hole axis, and the center of each of the ball grooves 51 is separated from each other, and has a Gothic arch shape. An escape groove 51a is provided at the intersection of the R shapes on the drawing. The material of the workpiece 50 is steel, and the workpiece is preliminarily processed with the through holes 50a, the ball grooves 51, and the relief grooves 61a by an internal broach, etc., and then heat-treated, and the hardness of the processed portion of the ball grooves indicated by diagonal lines is Before and after 60 HRC (Rockwell C scale). A machining allowance is left in the processed portion of the ball groove 51, and the processed portion is finished by the broach of the present invention.

As shown in FIG. 5, in the broach 31 of the present invention, three blades 43, 43, 43 having cutting edges are arranged on the circumference of the broach main body 32 having the front grip portion 41, and the blade front grip portion 41. The front guide 42 provided on the side is fixed to the longitudinal groove 32 a of the main body 32 with a bolt 46. Each of the blades 43 is sequentially provided with a finishing blade 34, an intermediate finishing blade 35, and a rough blade 36 in the front grip portion direction (downward in the drawing).

In each blade provided on the blade 43, the finishing blade 34 is formed with a relief surface which is a foam relief along the R shape adjacent to the rake surface, and processes the final R shape of the workpiece. The cutting edge of the intermediate finishing blade 35 has substantially the same shape as the finishing blade 34, and the finishing blade is the same size blade, whereas a cutting amount, for example, 8 μm to 15 μm is set. The material of the blade 43 provided with the cutting edge is made of cemented carbide and is coated with a hard coating.

As shown in FIG. 6, the cutting edge 39 of the rough blade 36 has a plurality of shape blades 39 a and a plurality of cutting blades 39 b alternately arranged in an R shape (first predetermined shape). Has been. The plurality of parting blades 39b have outer cutting edges 39c whose cutting edges are R-shaped (second predetermined shape) and concave cutting edges 39d formed inside the outer cutting edges alternately in the circumferential direction. Yes. The first blade 39b (1) of the rough blade is a cutting blade, and the second blade 39a (2) is a shape blade. N is an odd number of N ≧ 3, and the height in the blade length direction of the outer cutting edge 39c (N) of the cutting blade that is the Nth cutting blade is the shape blade that is the (N-1) th cutting blade. The height in the blade height direction of the lowest portion in the blade height direction of the concave cutting blade 39d (N) is larger than the height in the blade height direction of the cutting edge 39s (N-1) of 39a, and the N-1th cutting edge. The height of the cutting edge 39s (N- 1) of the shape blade that is the blade is lower than the height in the blade height direction, and the height of the cutting edge 39s (N + 1) of the shape blade 39a (N + 1) that is the N + 1th cutting edge The height is smaller than the height in the blade length direction of the outer cutting edge 39c (N) of the cutting edge 39b (N) which is the Nth cutting edge, and the height of the shaped blade 39a which is the N-1th cutting edge. It is made larger than the height of the cutting edge 39s (N-1) in the blade height direction.

The final edge of the rough edge is a cutting edge 39c (E), 39d (E), and three shape edges 39a are provided to form the previously described intermediate finish edge 35. Further, following the shaped blade 39a serving as the intermediate finishing blade 35, as described above, a finishing blade 34 group having R-shaped cutting blades 37 having the same height in the blade height direction is provided. The first predetermined shape of each cutting edge, the second predetermined shape excluding the concave cutting edge portion , and the finishing blade shape are R-shaped.

Processing of the ball groove using such a broach is performed as follows. In FIG. 6, as described above, the broaching 31 is passed along the through-hole 50a indicated by the dotted line to perform the groove processing. In the processing of the rough blade 36, the first blade is the cutting blade 39b (1), the tip of the concave cutting blade 39d (1) is at a position deeper than the front ball groove 51, and the concave portion (the tip 52a is missing). Are cut into the workpiece 50, and the portions 52 and 52 of horizontal oblique lines are cut and discharged. Next, the height in the blade height direction of the cutting edge 39s (2) or 39s (N-1) of the second cutting blade 39a (2) is the outer cutting edge 39c (1) of the first blade 39b (1). since smaller than the height of the blade length direction, reference numeral 53 portion or inverted trapezoidal portion of the vertical hatching is cut emissions.

Next, the height in the blade length direction of the outer cutting edge 39c (3) or 39c (N) of the third cutting blade is the shape of the second cutting blade 39a (2) or 39a (N-1). The cutting edge 39s (2) or the cutting edge 39s (2), which is larger than the height in the blade height direction of the cutting edge 39s (2) or 39s (N-1) , and the shape of the second blade of the concave cutting edge 39d (3) or 39d (N) At the position where the tip is deeper than 39 s (N-1) and leaving a concave portion (the tip 55b is missing), the portion 54 of the cut and cut portion is cut and discharged. Furthermore, the height of the cutting edge 39s (4) or 39s (N + 1) in the shape of the fourth blade in the blade height direction is the height of the outer cutting edge 39c (3) or 39c (N) of the third blade in the blade height direction. Since it is smaller than the height, the portion 55 of horizontal oblique lines, that is, the inverted trapezoidal portion is cut and discharged. By repeating this, the grooves are sequentially cut to increase the blade height.

The final blades of the rough blade 36 are the cutting blades 39c (E) and 39d (E) of the cutting blades, and the reference numeral 56 is cut and discharged. Subsequent to the final blade of the rough blade, the intermediate finish blade 35 having the same R-shaped cutting blade 38 as the shape blade 39a cuts and discharges the remaining 57 portions of the drawing portion, that is, the inverted trapezoidal portion (the tip portion 55b is not present). Further, the reference numeral 58 is sequentially cut and discharged, and is finished and cut into a final (finished) shape 60 by the cutting edge 37 of the finishing blade 34 to complete the ball groove processing.

As described above, according to the second embodiment of the present invention, in the finishing processing of the ball grooves and the like of the hardened material workpiece after quenching , the high-hardness chips are easily divided during the rough cutting, The chip discharge performance is improved, the finishing accuracy is improved, the scratches are reduced, the tool life is extended, and broaching can be performed, so that the production efficiency is dramatically improved. In processing the cutting edge according to the second embodiment, a grindstone having a concave R-shaped cross section with an opening angle of 90 degrees or less and a grindstone having a convex cross section are alternately used, and the ball groove is divided into two from the center. Te, can be easily processed is the cutting edge in the form up by sequentially shifting the grindstone in the direction of the arrow in FIG. Therefore, even if the base material is a difficult-to-cut material such as a cemented carbide, the manufacture becomes easy.

As in the case of the straight blade, the final blade 39b (E) is N = 3 for simplicity of explanation, but it goes without saying that the first blade is a shape blade and N may be an even number of 2 or more. Nor. The number of rough blades 36, intermediate finishing blades 35, finishing blades 34, cutting allowance, shape, dimensions, and the like are set as appropriate. In addition, the concave cutting edge may be curved and may be wavy as a whole, but various shapes such as straight lines can be selected.

  FIG. 7 is an explanatory view of the cutting edge of the spline groove machining showing the third embodiment of the present invention (the right half of the spline groove is shown and the left side is omitted. ) The third embodiment shows an example in which a spline groove is used instead of a ball groove. Since the groove shape is the same as that of the ball groove except that the groove shape is changed from a gothic arch shape to an involute curve, the same reference numerals are given and description thereof is omitted. As shown in FIG. 7, the present invention provides a broach with high precision and easy broach manufacture, such as various groove processing of ball grooves, spline grooves, gear tooth surfaces, etc., in particular, finishing groove processing with a broach of high hardness material. It became.

BRIEF DESCRIPTION OF THE DRAWINGS (a) of the flat keyway broach which shows 1st embodiment of this invention is a side view, (b) is a front view of a blade part. It is a perspective view of the cutting blade and the shape blade of the rough blade of the flat keyway broach showing the first embodiment of the present invention. It is a cutting explanatory drawing of the cutting edge of the keyway process using the flat keyway broach which shows 1st embodiment of this invention. It is a top view of the workpiece | work of the high hardness material which has a ball groove processed with the broach which shows 2nd embodiment of this invention. (A) which shows 2nd embodiment of this invention is a partial cross section side view of the broach of this invention which finishes a ball groove (a right side from a center line is a side view, and the left side of a center line is a cross-sectional view), (b ) Is a cross-sectional view taken along line AA of (a). It is incision explanatory drawing of the cutting edge of the ball groove process which shows 2nd embodiment of this invention. It is a cutting explanatory drawing of the cutting edge of the spline groove processing which shows 3rd embodiment of this invention.

1,31 Broach 4,34 Finishing blade (group)
5, 35 Shaped blades (mid-finished blades) with two or more blades provided after the final cutting blade
9, 39 Cutting blades 9a, 39a Cutting blades 9a (E), 39a (E) Final blades 9b, 39b Shaped blades 9c, 39c Outer cutting blades 9d, 39d Recessed cutting blades 9s, 39s Cutting blades 30, 60 Workpieces of shaped blades The final (finished) shape Z The height in the blade height direction of the lowest part in the blade height direction of the concave cutting blade

Claims (5)

In a broach provided with a plurality of cutting blades whose height in the height direction of the cutting blade gradually increases in the axial direction, a plurality of cutting blades whose shape of the cutting blade is a first predetermined shape, a plurality of cutting blades, Are arranged alternately, and the plurality of cutting blades include an outer cutting blade whose second cutting edge has a second predetermined shape, and a concave cutting blade formed inside the outer cutting blade. The height in the blade length direction of the outer cutting edge of the cutting blade that is the Nth cutting blade is larger than the height in the blade height direction of the cutting blade of the shaped blade that is the N-1th cutting blade. and the height of the blade height direction of the lowest portion in the blade height direction of the concave cutting edge is lower than the height of the blade height direction of the cutting edge of the first N-1 th shape blade is cutting edge, the (N + 1) The height in the blade height direction of the shaped blade that is the th cutting edge is the outer cutting edge of the cutting blade that is the Nth cutting edge. The height of the blade height direction of the blade the same or smaller, and are greater than the blade height direction height of the cutting edge of the N-1 th shape blade is cutting edge,
N is an odd number of N ≧ 3 when the first cutting edge is a cutting edge, and N is an even number of N ≧ 2 when the first cutting edge is a shaped blade.   The broach according to claim 1, wherein two or more shaped blades are provided following the final blade of the dividing blade.   The broach according to claim 2, wherein a finishing blade group is provided following the two or more shaped blades provided subsequent to the final blade of the cutting blade.   The broach according to claim 1, 2 or 3, wherein the plurality of cutting blades have the same cutting edge shape.   5. The shape according to claim 1, wherein a shape of a portion excluding a corresponding portion of the concave cutting edge of the first predetermined shape and the second predetermined shape are the same shape. brooch.

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