JP5783092B2 - Shaving cutter and manufacturing method thereof - Google Patents

Description

  The present invention relates to a shaving cutter used for gear finishing and a method for manufacturing the shaving cutter.

  As such a shaving cutter, Patent Document 1 discloses that the shaving cutter teeth can be implanted in the implantation groove formed on the outer periphery of the cutter body, so that grooves can be machined from the tooth tip side and the tooth root side. As a result, the land width of the center portion of the involute foam is increased by performing groove grinding twice so that the groove depth becomes smaller at the center portion of the tooth height with respect to the involute tooth profile. Yes. Similarly, Patent Document 2 proposes a method in which the land width of the tooth trace portion is made wider than the land width of the tooth tip or the tooth root by reducing the serration depth.

  Furthermore, Patent Document 3 discloses that the cutting edges located at both edges of the land streak direction are equal to each other as the land width becomes maximum at the position of the meshing circle of the shaving cutter and toward the tooth tip side and the tooth root side. There has been proposed a shaving cutter in which the land width is reduced so as to approach each other, or the cutting edge located at one end edge is linear but the land width is reduced. In such a shaving cutter, since the land width is reduced on the tooth tip side and the tooth base side of the land, which tends to be dull, the surface pressure when contacting the work gear can be increased. The sharpness can be made uniform as a whole.

Japanese Utility Model Publication No. 54-124290 (Fig. 4) Japanese Utility Model Publication No.59-1529 (FIG. 5 (b)) JP 2002-172524 A (FIG. 2)

  By the way, in the shaving cutter which made the land width small toward the tooth tip side and the tooth root side as described in these Patent Documents 1 to 3, those described in Patent Document 1 and Patent Document 3 were used. In the case where the cutting edges located at the both end edges of the land approach each other at equal intervals as it goes toward the tooth tip side and the tooth root side, the cutting edges at the both end edges are opposite to the "<" shape. The tooth tip side and the tooth root side with respect to the direction perpendicular to the tooth streak direction as viewed from the direction perpendicular to the tooth surface perpendicular to the surface passing through the center line in the tooth thickness direction of the tooth Are inclined in opposite directions, and the cutting edges at both end edges are also inclined in opposite directions. Further, in the one described in Patent Document 2 or the one in which the cutting edge located at one edge in Patent Document 3 is linear and the land width is reduced, the cutting edge located at the other edge. However, when viewed from the direction perpendicular to the surface passing through the center line in the tooth thickness direction of the tooth and facing the tooth surface, the tooth tip side and the tooth base side are inclined in opposite directions with respect to the direction perpendicular to the tooth streak direction. Will do.

  However, according to the cutting blade inclined in this way, since the scarf can be made parallel to the position of the meshing circle, the surface pressure is increased as described above, and the sharpness is further improved. However, it is only the cutting blade that inclines in one direction according to the specifications of the gear to be cut and the shaving cutter. On the other hand, an inclined cutting edge has an effect of dulling the sharpness. On the other hand, if the cutting blades located at both ends of the land are inclined together in one direction in which the above effect is exhibited according to the specifications of the work gear and shaving cutter, The surface pressure cannot be increased on the tooth base side or both of them, and the sharpness is also reduced.

  The present invention has been made under such a background. By reducing the land width, the surface pressure on the tooth tip side and the tooth root side is increased, while the sharpness is blunted by the inclination of the cutting blade in the opposite direction. An object of the present invention is to provide a shaving cutter and a method for manufacturing the shaving cutter capable of preventing the above-described problem and improving the sharpness of the land as a whole.

  In order to solve the above-described problems and achieve such an object, the shaving cutter of the present invention has a plurality of teeth provided on the outer periphery of a disc-shaped cutter body at intervals in the circumferential direction. In the shaving cutter in which lands are formed between adjacent serration grooves by forming serration grooves on the tooth surfaces of the teeth, the lands are perpendicular to the surface passing through the center in the tooth thickness direction of the teeth. A pair of vertical sides extending perpendicularly to the tooth streak direction of the teeth, a pair of oblique sides obliquely intersecting the vertical sides and extending parallel to each other, and the tooth tip side And a pair of end sides that are located on the tooth root side and extend toward the tooth trace direction. The land width of the land in the tooth trace direction is the maximum land width L and the minimum land width. With width l L / l is characterized in that there is a range of less than 1.8 greater than 1.2.

  In such a shaving cutter, the land has a pair of vertical sides extending perpendicularly to the tooth trace direction as viewed from a direction perpendicular to the surface passing through the center of the tooth thickness direction of the tooth and facing the tooth surface. Each of the vertical sides has a pair of oblique sides that extend obliquely and have a pair of oblique sides, and a cutting edge is formed between the pair of vertical sides and the oblique sides. By setting the direction of inclination to a direction that improves sharpness according to the specifications of the gear to be cut or shaving cutter, there is no part that inclines in the opposite direction and blunts the sharpness, so only sharpness improvement effect Can be obtained. And, the land width, which is the width of the land in the direction of the tooth trace, gradually decreases as it goes toward the tooth tip side and the tooth root side between the vertical side and the hypotenuse as viewed from the direction facing the tooth stripe direction. A sharper sharpness can be ensured by increasing the surface pressure.

  However, the ratio L / l between the maximum land width L, which is the maximum value of the land width, and the minimum land width 1, which is the minimum value, is too small, that is, the maximum land width L and the minimum land width l do not change so much. If this is the case, the surface pressure cannot be increased in this way on the tooth tip side or the tooth root side, and a sharp sharpness cannot be ensured. On the other hand, if the ratio L / l is too large, the maximum land width L is determined by the width of the land of the shaving cutter and the width of the serration groove. May become too small and cause chipping. For this reason, the ratio L / l exceeds 1.2 and is less than 1.8.

  In addition, if the position where the width of the land becomes the maximum land width L is too close to the tooth tip side or the tooth root side, the sharpness will be impaired even at the tooth tip or the tooth root where the sharpness tends to be dull. There is a risk of tooth profile accuracy degradation. Accordingly, the position where the width of the land becomes the maximum land width L is a distance between the pair of end edges when viewed from a direction perpendicular to the surface passing through the center of the tooth thickness direction of the tooth and facing the tooth surface of the tooth. The ratio h / H formed by the distance h in the tooth height direction of the tooth from the tooth edge side edge to the position where the land width is the maximum land width L of the pair of edges. It is desirable to be positioned in the central portion in the tooth height direction so that the value of the upper limit is more than 0.2 and less than 0.7.

  By the way, in the shaving cutter of the said structure, when a land width becomes small gradually as it goes to a tooth tip side and a tooth root side as mentioned above, there exists a possibility that intensity | strength may fall by the tooth tip side and tooth root side of these lands. Occurs. In particular, when the groove depth of the serration groove is increased on the tooth tip side and the tooth root side as in the shaving cutters described in Patent Documents 1 and 2, the land strength on the tooth tip side and the tooth root side is further reduced. It will be. On the other hand, however, if the groove depth of the serration groove is made shallower over the entire length in order to ensure the land strength, chip removal and cutting oil supply will be impaired, and smooth gear finishing will be achieved. It becomes difficult to perform processing.

  Therefore, in order to ensure the strength of the lands on the tooth tip side and the tooth root side while maintaining such a smooth discharge of chips and a reliable supply of cutting oil, the groove bottom surface of the serration groove is A step is formed that extends on the extension line of the pair of vertical sides or the pair of oblique sides when viewed from the direction facing the tooth surface, and the groove depth of the portion between the steps is increased. Is desirable.

  As a result, even when the step extends on any extension line of the pair of vertical sides or the pair of oblique sides, the stepped groove-like groove bottom faces through the step on the tooth tip side and the tooth root side of the land. As a result of the formation of a raised portion, the land strength on the tooth tip side and the tooth base side can be improved. On the other hand, the bottom surface of the serration groove between the steps is deepened and is formed so as to extend from the tooth tip to the tooth root, thereby facilitating reliable chip discharge and supply of cutting oil. it can.

  On the other hand, to manufacture the shaving cutter having the above-described configuration, the tooth surface of the cutter body has serration grooves along the vertical sides and serration grooves along the oblique sides intersecting each other so that the teeth of the teeth are crossed with each other. What is necessary is just to form over a tooth tip and a tooth root. Regardless of which serration groove is formed first, one side of the vertical side and the hypotenuse side is formed between the tooth tip and the tooth root at both end edges of the land, and then intersects this one side. Thus, the other side is formed. Further, when these serration grooves are formed, if the groove depths are different, a shaving having a stepped serrated groove bottom surface in which the groove depth between the steps as described above is increased. A cutter can be formed.

  When the shaving cutter is manufactured in this way, the groove bottom surface composed of the serration groove along the vertical side and the serration groove along the oblique side corresponds to the involute curve formed by the tooth surface of the tooth. The groove wall surface extending from the groove bottom surface to the tooth surface is preferably formed so as to be perpendicular to the groove bottom surface and the tooth surface, thereby ensuring the capacity of the serration groove. Thus, more reliable chip discharge and cutting oil supply can be achieved, and the tooth surface of the land and the groove wall surface are perpendicularly intersected at a pair of vertical sides and hypotenuses of the land as the cutting blade. The teeth can be perpendicular to each other, and a sharper sharpness can be secured. Even when the tooth surface is re-polished, the groove bottom surface also extends backward in parallel with the involute curve, so that the groove depth is not partially reduced and the number of re-polishing is ensured. Can do. Further, the shape of the tooth surface of the land does not change after re-polishing.

  As described above, according to the present invention, the ratio L / l between the maximum land width L and the minimum land width l is set to a predetermined value while avoiding the formation of a cutting blade that is inclined in the direction of dullness. Since the land width is gradually reduced toward the tooth tip side and the tooth root side so as to be within the range, the surface pressure on the tooth tip side and the tooth root side is increased, and the land is uniform and sharp. Can be definitely obtained.

It is a side view which shows one Embodiment of the shaving cutter of this invention. It is a perspective view of the tooth | gear of embodiment shown in FIG. 1 (however, the level | step difference is abbreviate | omitting illustration). It is the figure which looked at the tooth surface of the tooth | gear shown in FIG. 2 from the direction which opposes a tooth surface perpendicular | vertical to the surface which passes along the center of the tooth thickness direction of this tooth | gear. It is YY sectional drawing in FIG. It is ZZ sectional drawing in FIG. It is a figure which shows the processing cycle of the shaving process of a plunge cut system.

  1 to 5 show an embodiment of a shaving cutter according to the present invention. In this embodiment, the cutter body 1 is formed in a substantially disc shape with an axis O as the center, as shown in FIG. 1, by a hard material such as high-speed tool steel, and a plurality of teeth 2 are formed on the outer peripheral surface thereof. Serrated grooves 4 that are provided at equal intervals in the circumferential direction and extend in the tooth height direction (vertical direction in FIG. 3) on the tooth surface 3 of these teeth 2 as shown in FIGS. 2 and 3. A plurality of gaps are formed at intervals in the left-right direction in FIG. 3, and portions between these serration grooves 4 are lands 5, and serrations are formed by these serration grooves 4 and lands 5.

  The land 5 is a pair of perpendicularly extending in the direction of the teeth of the tooth 2 as shown in FIG. 3 when viewed from the direction facing the tooth surface 3 perpendicular to the surface passing through the center of the tooth 2 in the thickness direction. A vertical side 5a, a pair of oblique sides 5b that cross each other and extend parallel to each other, and a tooth tip side (upper side in FIG. 3) and a tooth base side (lower side in FIG. 3) of the tooth 2 Each of the pair of vertical sides 5a and the hypotenuses are located at both ends of the land 5 in the direction of the tooth traces and are surrounded by a pair of end sides 5c that are positioned and extend in the direction of the tooth traces. 5b is a cutting edge.

  By forming the lands 5 in a hexagonal shape in this way, the width of the lands 5 in the tooth line direction, that is, the land width becomes the maximum land width L at the center in the tooth height direction, and from the position of the maximum land width L. The width gradually decreases toward the tooth tip side and the tooth root side, and becomes the minimum land width l at least one of the positions of the end side 5c on the tooth tip side and the end side 5c on the tooth root side. The ratio L / l between the maximum land width L and the minimum land width l is in the range of more than 1.2 and less than 1.8.

  Further, in the present embodiment, the position where the land width becomes the maximum land width L as described above is the same as that seen from the direction facing the tooth surface 3 perpendicular to the surface passing through the center of the tooth 2 in the tooth thickness direction. The ratio h / H that the distance h in the tooth height direction from the tooth side edge 5c to the position of the maximum land width L with respect to the tooth height H between the pair of edges 5c of the land 5 is shown in FIG. Is in a range of more than 0.2 and less than 0.7, that is, the land 5 is positioned substantially at the center in the tooth height direction. In the tooth 2 shown in FIG. 2, the lands 5 are left at both ends of the tooth surface 3 in the streak direction, but the lands 5 may not be formed at least one of these both ends. Further, when viewed from a direction perpendicular to the surface passing through the center of the tooth thickness direction of the tooth 2 and facing the tooth surface 3, the pair of vertical sides 5a are perpendicular to the tooth trace direction, but the pair of end sides 5c are teeth. It suffices if it extends in the streak direction, that is, it may be slightly obtuse or acute with respect to the pair of vertical sides 5a.

  Here, in this embodiment, the land 5 is configured such that the vertical side 5a and the oblique side 5b of the both ends intersect at the position where the maximum land width L is as shown in FIG. The position of the width L is only one point in the tooth height direction. However, even if the vertical sides 5a at both ends or the hypotenuses 5b at both ends overlap in the tooth height direction, the position where the maximum land width L is within the above range has a width in the tooth height direction. Good. Further, in FIG. 3, the minimum land width 1 is set at the end 5c on the tooth tip side, but the minimum land width 1 may be set at the end 5c on the tooth base side. The end side 5c on the front side and the tooth height side may be equal to each other and have the minimum land width l.

  On the other hand, in the present embodiment, the serration groove 4 has a groove bottom surface 4a that is substantially the same as the involute curve formed by the tooth surface of the tooth 2 (the surface of the land 5 forming the above-mentioned eccentric hexagonal shape) 3 as shown in FIG. The groove wall surface 4b extending from the groove bottom surface 4a to the tooth surface 3 is formed so as to be perpendicular to the groove bottom surface 4a and the tooth surface 3 as shown in FIG. ing.

  However, the groove bottom surface 4a is formed with a step 4c extending on the extension line of the pair of oblique sides 5b of the land 5 as shown by a broken line in FIG. 3 when viewed from the direction facing the tooth surface 3. In the portion between the step 4c and the groove wall surface 4b adjacent to each other in the tooth trace direction, the groove depth of the serration groove 4 is made one step deeper than between the step 4c and the land 5 as shown in FIG. The bottom surface 4a is stepped. The step 4c is perpendicular to the groove bottom surface 4a.

  In one embodiment of the manufacturing method of the present invention when manufacturing a shaving cutter having such serrations formed, serration grooves 4 along the vertical sides 5a and the oblique sides 5b are formed on the tooth surfaces 3. The serration groove 4 may be formed so as to extend between the tooth tip and the tooth root of the tooth 2 so as to cross each other. Either of the serration grooves 4 may be formed first, but if the serration groove 4 along the oblique side 5b is made deeper than the serration groove 4 along the vertical side 5a, the step-shaped groove bottom surface as described above A serration groove 4 having 4a can be formed.

  For example, in the shaving cutter having the above-described structure manufactured by such a manufacturing method, the position where the width of the land 5 becomes the maximum land width L is positioned at the substantially central portion in the tooth height direction as described above. The land width gradually decreases from the tooth tip side to the tooth tip side to the tooth tip side, so that at least one of the tooth tip side or the tooth root side (the tooth tip side in this embodiment) has a minimum land width l. .

  In other words, in the shaving process, the land width decreases from the peripheral position of the meshing circle with sharpness toward the tooth tip side and the tooth root side where the sharpness becomes dull, and conversely, the surface pressure against the work gear increases. . For this reason, the sharpness on the tooth tip side and the tooth root side can be compensated by increasing the surface pressure, and the cutting edge of the land 5 can be made uniform by the above cutting blade over the entire tooth length direction. Thus, it is possible to finish the work gear with high accuracy.

  The land 5 has a pair of vertical sides 5a extending perpendicularly to the streak direction of the tooth 2 as viewed from a direction perpendicular to the surface passing through the center of the tooth thickness direction of the tooth 2 and the vertical direction of these teeth. Each of the pair of vertical sides 5a and the hypotenuse 5b acts as a cutting edge, and each of the hypotenuses includes a pair of hypotenuses 5b obliquely intersecting the sides 5a and extending in parallel with each other. By setting the direction of inclination of 5b to a direction that improves the sharpness according to the specifications of the work gear and the shaving cutter, a cutting blade that is inclined in the direction opposite to the hypotenuse 5b is not formed. Therefore, according to the shaving cutter having the above-described configuration, there is no cutting edge that inclines in the opposite direction and blunts the sharpness, so that only the sharpness improving effect can be obtained, and the finishing process with higher accuracy is achieved. It can be performed.

  In addition, the ratio L between the maximum land width L of the land 5 that is maximum at the substantially central portion in the tooth height direction and the minimum land width l of the land 5 that is minimum on the tooth tip side or the tooth root side or both. / L is in the range of more than 1.2 and less than 1.8, so that the land 5 can be chipped on the tooth tip side or the tooth base side while the above-mentioned sharpness uniformity is reliably achieved. You can prevent it. That is, if the ratio L / l is 1.2 or less and the difference between the maximum land width L and the minimum land width l is too small, the sharpness cannot be made uniform as described above. If the ratio L / l is large at 1.8 or more, the land width becomes too small on the tooth tip side and / or the tooth root side where the minimum land width l is reached, and the land 5 is chipped.

  Furthermore, in this embodiment, the distance h in the tooth height direction from the edge 5c on the tooth base side of the eccentric hexagon formed by the land 5 to the position where the maximum land width L is obtained is the tooth height H between the pair of edges 5c. The ratio h / H to be in the range of more than 0.2 and less than 0.7 is such that the maximum land width L is located at a substantially central portion of the land 5 in the tooth height direction. Thus, it is possible to prevent the sharpness from being further impaired on the tooth tip side and the tooth base side, which tend to be dull, and the deterioration of the tooth profile accuracy can be prevented. That is, if the position where the maximum land width L is located is closer to the tooth tip side or the tooth root side than the above range, the sharpness on this near side is impaired and the tooth profile accuracy of the work gear may be deteriorated.

  On the other hand, in the present embodiment, the strength of the land 5 on the tooth tip side or the tooth base side is ensured by setting the ratio L / l of the maximum land width L and the minimum land width l within the above range as described above. In addition to this, in addition to this, the groove bottom surface 4a of the serration groove 4 is an extension of the pair of vertical sides 5a or the pair of oblique sides 5b when viewed from the direction facing the tooth surface 3. The step 4c extending on the extension line of the pair of hypotenuses 5b (in this embodiment) is formed, and the tooth tip side and the tooth base side can also be formed by forming a stepped surface with a shallow groove depth of the step 4c. The strength of the land 5 is improved.

  Therefore, on the tooth tip side and the tooth root side of the land 5 where the groove depth is shallowed by the step 4c, of the pair of vertical sides 5a and the pair of oblique sides 5b serving as cutting edges, in the present embodiment, a pair of vertical sides. Since the groove bottom surface 4a of the serration groove 4 rises to a position closer to 5a and the wall thickness is secured, the strength of the land 5 can be improved on the tooth tip side and the tooth base side to prevent the occurrence of chipping or the like. it can. On the other hand, since the groove depth is increased from the tooth tip to the tooth root between the oblique side 5b and the step 4c sandwiching the serration groove 4, a pair of vertical sides 5a and oblique sides that are cutting edges The chips generated by 5b can be discharged smoothly, and the cutting oil supplied at the time of shaving can be reliably distributed to the processing site.

  Moreover, in one embodiment of the manufacturing method of the shaving cutter of the present invention when manufacturing such a shaving cutter, the serration groove 4 along the vertical side 5a of the land 5 and the tooth surface 3 as described above, The serration groove 4 along the oblique side 5b is formed between the tooth tip and the tooth root of the tooth 2 so as to intersect with each other, and the general serration groove extends perpendicularly to the tooth line direction. The shaving cutter can be manufactured relatively easily only by combining the shaving cutter and the method of manufacturing the shaving cutter in which the serration grooves extend obliquely in one direction.

  At this time, the groove bottom surface 4a has a side along the deep serration groove 4 by making the groove depth different between the serration groove 4 along the vertical side 5a and the serration groove 4 along the oblique side 5b. Since the step 4c is formed on the extended line of the shaving cutter, a shaving cutter having a thickness sufficient between the tooth tip side and the tooth base side as described above and having a deep groove between the step 4c is also relatively It can be manufactured easily.

  Further, in the present embodiment, the groove bottom surface 4a composed of the serration groove 4 along the vertical side 5a and the serration groove 4 along the oblique side 5b is substantially the same as the involute curve formed by the tooth surface 3 of the land 5 of the tooth 2. The groove wall surface 4b extending from the groove bottom surface 4a to the tooth surface 3 extends in parallel with the groove bottom surface 4a and the tooth surface 3 so that the vertical side 5a and the oblique side 5b are cut edges. The teeth are perpendicular to each other. For this reason, it is possible to secure a large capacity by the serration groove 4 to achieve more reliable chip discharge and cutting oil supply, and to further sharpen the pair of vertical sides 5a and hypotenuses 5b which are the cutting edges of the lands 5. Can be secured. Further, even when the tooth surface 3 of the land 5 is re-polished, the groove bottom surface 4a of the serration groove 4 extends backward in parallel with the involute curve, so that the groove depth of the serration groove 4 is partially Therefore, it can be maintained without reducing the number of re-polishing. Further, the shape of the tooth surface 3 of the land 5 by the pair of vertical sides 5a and the oblique sides 5b does not change after the re-polishing.

  In the manufacturing method of the above embodiment, the step 4c is formed on the tooth surface 3 in the shaving cutter of the above embodiment by making the serration groove 4 along the oblique side 5b deeper than the serration groove 4 along the vertical side 5a. As viewed from the opposite direction, the lands 5 extend on the extended lines of the pair of oblique sides 5b. Conversely, the serration grooves 4 along the vertical sides 5a are deeper than the serration grooves 4 along the oblique sides 5b. Then, the serration groove 4 having the stepped groove-like groove bottom surface 4a in which the step 4c extends on the extension line of the vertical side 5a and the groove depth is increased therebetween can be formed.

  Also in the shaving cutter manufactured in this way, the thickness can be secured at the portion of the land 5 that is continuous from the groove bottom surface 4a to the hypotenuse 5b on the tooth tip side and the tooth root side, so that the strength can be improved. Smooth chip discharge and cutting oil supply can be promoted by the deep groove portion.

  Examples of the present invention will be given below to demonstrate the effects of the present invention. In this example, the land 5 is substantially based on the embodiment shown in FIG. 1 to FIG. 5 when viewed from the direction facing the tooth surface 3 perpendicular to the surface passing through the center of the tooth 2 in the tooth thickness direction. A pair of vertical sides 5a extending perpendicularly to the two tooth trace directions, a pair of oblique sides 5b obliquely intersecting the vertical sides 5a and extending parallel to each other, and the tooth tip side and the tooth root side of the tooth 2 The land 5 is formed in a hexagonal shape surrounded by a pair of edges 5c extending in the direction of the tooth trace, and the land width of the land 5 in the direction of the tooth trace is the ratio of the maximum land width L to the minimum land width l (hereinafter referred to as land Three shaving cutters with L / l in the range of more than 1.2 and less than 1.8 were manufactured. Let these be Examples 1-3.

  Among Examples 1 to 3, in Example 1, when viewed from the direction facing the tooth surface 3 perpendicular to the surface passing through the center of the tooth thickness direction of the tooth 2, between the pair of end sides 5 c of the land 5. The distance in the tooth height direction from the edge 5c on the tooth base side to the position where the land width becomes the maximum land width L (hereinafter referred to as the position of the maximum land portion) The ratio of h (hereinafter referred to as the tooth height ratio) h / H is set to be in the range of more than 0.2 and less than 0.7, 0.2 or less in the second embodiment, and 0.2 in the third embodiment. 7 or more.

  On the other hand, as a comparative example with respect to Examples 1 to 3, the land is surrounded by a pair of vertical sides, oblique sides, and end sides as seen from a direction perpendicular to the surface passing through the center in the tooth thickness direction of the teeth. Three shaving cutters that have the shape of a flat hexagon and have the maximum land width L and the tooth height H between the pair of edges equal to those of the first to third embodiments, but the land ratio L / l is 1.2 or less. Three shaving cutters having a land ratio L / l of 1.8 or more were manufactured. These are referred to as Comparative Examples 1 to 3 and Comparative Examples 4 to 6, respectively. Of these Comparative Examples 1 to 6, in Comparative Examples 1 and 4, the tooth height ratio h / H is in the range of more than 0.2 and less than 0.7, and in Comparative Examples 2 and 5, 0.2 or less. In Examples 3 and 6, it was set to 0.7 or more.

  Then, with the shaving cutters of Examples 1 to 3 and Comparative Examples 1 to 6, the work gear was shaved under the same conditions, the tooth profile error at that time was measured, and the presence or absence of a chipped land was confirmed. . As a result, the maximum land width L (mm), the minimum land width l (mm), the tooth height H (mm) of each shaving cutter, the position h (mm) of the maximum land portion, the land ratio L / l, and the tooth height. Table 1 shows the ratio h / H.

  The other specifications of the shaving cutter are as follows: the cutter body is made of high-speed tool steel, the outer diameter is 221.7 mm, the number of teeth is 71, the tooth twist angle is 15 ° RH, the tooth width is 25.4 mm, and the serration pitch is 1. In order to confirm the effects of the land ratio L / l and the tooth height ratio h / H, the groove depth was set to 0.68 mm so that no step was formed on the groove bottom surface of the serration groove.

  The specifications of the gear to be cut are made of hardened steel with an outer diameter of 47.5 mm, a module of 2.96, a pressure angle of 17.5 °, a number of teeth of 13, a twist angle of 0 °, and a tooth width of 20 mm. Machining conditions are plunge cut as the machining method, cutter rotation speed 150 rpm, plunge feed 0.5 mm / min, dwell time T1: 3 sec, T2: 3 sec, T3: 5 sec and BM (back movement) amount: 0.02 mm there were.

  FIG. 6 shows a processing cycle of the plunge cut type shaving processing. As shown in FIG. 6, while the cutter body 1 is rotated forward, from the start of machining (a) to the start of cutting (b), the workpiece gear is fast-forwarded and approached from the start of cutting (b) to when the cutting is stopped ( Until c), cutting is performed by the above plunge feed. Next, in order to remove the unevenness on the finished surface and perform the shaving completely, the cutting is stopped from the time when the cutting is stopped (c) to the time when the reverse rotation is started (d). The time (sec) during this period is the dwell time T1.

  Further, the state where the cutting is stopped is maintained from the start of reverse rotation (d) to the reverse start of rotation (e) while rotating the cutter body 1 in the reverse direction. This time (sec) is the dwell time T2. Next, the cutter body 1 is moved backward with respect to the work gear between the reverse start (e) and the reverse stop (f), and the reverse operation is performed while reversely rotating from the reverse stop (f) to the start of disengagement (g). In this state, stop the cutting and correct the elastic deformation. The amount of backward movement (back movement) of the cutter body 1 from the backward start time (e) to the backward stop time (f) is the BM amount, and between the backward stop time (f) and the release start time (g). The time (sec) is the dwell time T3. Further, from the start of separation (g) to the end of machining (h), the cutter body 1 is separated from the work gear by rapid feed and returns to the start position.

  From the results of Table 1, the land ratio L / l is 1.35 in the range of more than 1.2 and less than 1.8, and the tooth height ratio h / H is more than 0.2 in the range of more than 0.2 and less than 0.7. In Example 1, which is 51, the tooth profile error is 4 μm, which satisfies the old JIS (JIS B 1702: 1960) class 0 (4 μm or less), and no lands were found missing. In addition, although the land ratio L / l is in the range of more than 1.2 and less than 1.8, the tooth height ratio h / H is 0.19 which is 0.2 or less and Example 2 and 0.7 or more. In Example 3, which was 0.73, the tooth profile error did not satisfy the old JIS class 0, but the result satisfied the class 1 (6 μm or less), and no missing land was recognized.

  In Comparative Examples 1 to 6, in which the land ratio L / l is 1.2 or less, or in the range of 1.8 or more, the tooth profile error does not satisfy the class 1 of the old JIS. These were incompatible as products, and in particular, in the comparative examples 4 to 6 in which the land ratio L / l was 1.8 or more, it was recognized that the lands were chipped. In these Comparative Examples 4 to 6, a large difference in tooth profile error due to a difference in tooth height ratio h / H was not recognized.

1 cutter body 2 teeth 3 tooth surface 4 serration groove 4a groove bottom surface 4b groove wall surface 4c step 5 land 5a vertical side 5b oblique side 5c end side O axis of cutter body 1 L maximum land width l minimum land width H between a pair of ends 5c Tooth height h The distance in the tooth height direction of the tooth 2 from the edge 5c on the tooth base side to the position where the land width becomes the maximum land width L

Claims (5)

  A plurality of teeth are provided on the outer periphery of the disc-shaped cutter body at intervals in the circumferential direction, and serration grooves are formed on the tooth surfaces of these teeth, thereby forming lands between adjacent serration grooves. In the shaving cutter as described above, the land has a pair of vertical sides extending perpendicularly to the tooth trace direction of the tooth as viewed from a direction perpendicular to the surface passing through the center of the tooth thickness direction of the tooth and facing the tooth surface. And a pair of hypotenuses obliquely crossing these vertical sides and extending in parallel with each other, and a pair of end sides positioned on the tooth tip side and the tooth base side of the tooth and extending in the tooth streak direction. The land width of the land in the above-mentioned tooth line direction is in the range where the ratio L / l of the maximum land width L to the minimum land width l is more than 1.2 and less than 1.8. Shaving mosquito characterized by Data.   The land is a portion of the pair of edges with respect to the tooth height H between the pair of edges when viewed from a direction perpendicular to the surface passing through the center of the tooth thickness direction of the teeth. The ratio h / H formed by the distance h in the tooth height direction of the teeth from the edge on the tooth base side to the position where the land width becomes the maximum land width L is in the range of more than 0.2 and less than 0.7. The shaving cutter according to claim 1, wherein the shaving cutter is provided.   The groove bottom surface of the serration groove has a step extending on the extension line of the pair of vertical sides or the pair of oblique sides when viewed from the direction facing the tooth surface, and the groove depth between the steps is deep. The shaving cutter according to claim 1, wherein the shaving cutter has a stepped surface shape.   It is a manufacturing method of the shaving cutter according to any one of claims 1 to 3, wherein a serration groove along the vertical side and a serration groove along the oblique side are formed on the tooth surface. A method for producing a shaving cutter, characterized in that the shaving cutter is formed between the tooth tip and the tooth base so as to cross each other.   A groove bottom surface comprising a serration groove along the vertical side and a serration groove along the oblique side extends backward in parallel to the involute curve formed by the tooth surface of the tooth, and extends from the groove bottom surface to the tooth. 5. The method for manufacturing a shaving cutter according to claim 4, wherein the groove wall surface reaching the surface is formed to be perpendicular to the groove bottom surface and the tooth surface.

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