JP5776594B2 - 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 edges of the land are inclined at a constant inclination 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 tip side, the tooth root 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 hexagonal shape is formed when viewed from the direction facing the surface. The eccentric hexagons formed by the lands are located on opposite sides of each other and are opposite to each other, and are inclined with respect to the direction perpendicular to the tooth traces of the teeth. And a pair of steeply inclined sides extending at a larger inclination angle than the gently inclined side in the same direction as the gently inclined side with respect to a direction perpendicular to the tooth trace of the tooth , Tooth tip side and tooth base of the above teeth And a pair of edges extending toward the tooth trace direction of the tooth, and the land width in the tooth trace direction gradually decreases toward the tooth tip side and the tooth root side of the tooth. It has a shape.

  In such a shaving cutter, the land has an eccentric hexagonal shape as viewed from the direction perpendicular to the surface passing through the center of the tooth thickness direction of the tooth and facing the tooth surface, and each of the eccentric hexagons is on the opposite side. A pair of gently sloping sides extending in a direction perpendicular to the tooth streaks and a pair of gently sloping sides perpendicular to the tooth streaks. A pair of steeply inclined sides that extend at an inclination angle larger than the gently inclined side, and are located on the tooth tip side and the tooth root side of the tooth and directed toward the tooth trace direction of the tooth. The cutting edge is formed on each of the pair of gently inclined sides and steeply inclined sides.

  For this reason, by setting the direction of inclination of these slow and steep hypotenuses to a direction that improves sharpness according to the specifications of the work gear and shaving cutter, there is no portion that inclines in the opposite direction and blunts the sharpness. In addition, since there is no cutting edge extending vertically to the tooth trace, only the effect of improving the sharpness can be obtained. The land width of the land in the above-mentioned tooth streak direction is gradually reduced as it goes toward the tooth tip side and the tooth root side between the steep and slant sides seen from the direction opposite to the tooth streak direction, thereby increasing the surface pressure. Therefore, a sharper sharpness can be ensured.

  Here, the pair of gently inclined sides and the pair of steeply inclined sides extend in parallel with each other when viewed from a direction facing the tooth surface perpendicular to a surface passing through the center of the tooth thickness direction of the tooth. In this case, the inclination angle was changed relatively easily by forming the serration groove between the lands by two processes with different angles with respect to the direction perpendicular to the teeth as will be described later. Slow and steep hypotenuse can be formed.

  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 are not so different. If this is the case, the surface pressure cannot be increased on the tooth tip side or the tooth base side as described above, 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, it is desirable that the ratio L / l is greater than 1.2 and 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 stepped surface shape in which a step extending on the extension line of the pair of gently inclined sides or the pair of steeply inclined sides as viewed from the direction facing the tooth surface is formed, and the groove depth between the steps is deepened. Is desirable.

  As a result, even when the step extends on any extension line of the pair of gently inclined sides or the pair of steeply inclined sides, the groove bottom surface of the step surface has a step on the tooth tip side and the tooth root side of the land. As a result, a portion raised by one step is formed, and the land strength on the tooth tip side and the tooth root 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, in order to manufacture the shaving cutter having the above-described configuration, the serration groove along the gently inclined side and the serration groove along the steeply inclined side intersect with each other on the tooth surface of the cutter body. What is necessary is just to form over the tooth tip and tooth base of the said tooth | gear. Regardless of which serration groove is formed first, one side of the gently inclined side and the steeply inclined side is formed between the tooth tip and the tooth root at both end edges of the land, and then this one side The other side is formed so as to intersect. 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, an involute formed by the tooth surface of the tooth includes a serration groove along the gently inclined side and a bottom surface of the serration groove along the steeply inclined side. It is desirable that the groove wall surface extending from the groove bottom surface to the tooth surface extends substantially parallel to the curve and is perpendicular to the groove bottom surface and the tooth surface. It is possible to secure a capacity to achieve more reliable chip discharge and supply of cutting oil, and at each pair of gently sloping sides of the land that is used as a cutting edge, the tooth surface of the land and the groove wall surface are perpendicular to each other. 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, it is possible to increase the surface pressure on the tooth tip side and the tooth base side of the land while avoiding the formation of the cutting blade that is inclined in the direction of reducing the sharpness. As a result, the entire land can be evenly sharp.

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 has a hexagonal shape 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 tooth thickness direction. The six sides of the eccentric hexagon include a pair of gently inclined sides 5a forming a pair of opposite sides extending at an inclination angle α with respect to a direction perpendicular to the streaks of the teeth 2 (the two-dot chain line direction in FIG. 3), and these A pair of opposite sides extending at an inclination angle β larger than the inclination angle α and extending in a direction perpendicular to the tooth stripe in the same direction as the gentle inclination side 5a while intersecting each of the gentle inclination sides 5a with an obtuse angle. A steeply inclined side 5b and a pair of opposite sides 5c that are located on the tooth tip side (upper side in FIG. 3) and tooth base side (lower side in FIG. 3) of the tooth 2 and extend toward the tooth streak direction. It is configured.

  In addition, the pair of gently inclined sides 5a, the pair of steeply inclined sides 5b, and the pair of end sides 5c extend in parallel with each other when viewed from the direction facing the tooth surface 3 in the present embodiment. Of these, each of the pair of gently inclined sides 5a and steeply inclined sides 5b located at both edges of the land 5 in the tooth trace direction 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. Here, in the present embodiment, the ratio L / l between the maximum land width L and the minimum land width l is set to a range greater 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. As shown in FIG. 6, the ratio h of the distance h in the direction perpendicular to the tooth streak 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 / H is set so as to be in the 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 the direction facing the tooth surface 3 perpendicular to the surface passing through the center of the tooth thickness direction of the tooth 2, the pair of end sides 5 c only need to extend in the tooth line direction, that is, parallel to the tooth line. It may be slightly inclined with respect to any direction.

  Here, in this embodiment, the land 5 is configured such that the gently inclined side 5a and the steeply inclined side 5b intersect at both ends at the position where the maximum land width L is as shown in FIG. Therefore, the position of the maximum land width L is only one point in the tooth height direction. However, the gently inclined sides 5a at both ends or the steeply inclined sides 5b at both ends overlap in the tooth height direction, and the position where the maximum land width L is within the above range has a width in the tooth height direction. It may be. 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 steeply inclined 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 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 groove 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, the tooth surface 3 has serration grooves 4 along the gently inclined side 5a and the steeply inclined side 5b. And the serration groove 4 along the line 2 may be formed 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 steeply inclined side 5b is made deeper than the serration groove 4 along the gently inclined side 5a, the stepped surface shape as described above The serration groove 4 having the groove bottom surface 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 extends at an inclination angle α with respect to the direction perpendicular to the tooth trace of the tooth 2 when viewed from the direction perpendicular to the tooth surface 3 perpendicular to the surface passing through the center of the tooth 2 in the thickness direction. An eccentric hexagon having a pair of gently inclined sides 5a and a pair of steeply inclined sides 5b extending in a direction same as the gently inclined sides 5a, but extending at a larger inclination angle β with respect to a direction perpendicular to the tooth traces. Each of the pair of gentle and sloping inclined sides 5a and 5b acts as a cutting edge. For this reason, by setting the direction of inclination of these gently steep inclined sides 5a and 5b to a direction that improves the sharpness according to the specifications of the work gear and the shaving cutter, it is perpendicular to the cutting blade and the tooth trace that are inclined in the opposite direction. Since the cutting blade extending in the direction is not formed, only the sharpness improving effect of the cutting blade can be obtained. Therefore, according to the shaving cutter having the above-described configuration, finishing with higher accuracy can be performed.

  Further, in the present embodiment, 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 of the land 5 that is minimum on the tooth tip side, the tooth root side, or both of them. Since the ratio L / l to l is in the range of more than 1.2 and less than 1.8, the land 5 on the tooth tip side and the tooth root side can be reliably achieved while ensuring uniform sharpness as described above. It is possible to prevent the chipping from occurring. That is, when 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 above-described sharpness cannot be achieved and the tooth profile accuracy cannot be achieved. On the contrary, if the ratio L / l is larger than 1.8, 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 formed. There is a risk of chipping.

  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 seen from the direction facing the tooth surface 3, and the pair of gently inclined sides 5a or the pair of suddenly inclined sides 5b. Steps 4c extending on the extension lines (in this embodiment, the extension lines of the pair of steeply inclined sides 5b) are formed, and these tooth tips can also be formed by making the step depths 4c shallower. The strength of the land 5 on the side and the tooth base side is improved.

  Accordingly, 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 gently inclined sides 5a and the pair of steeply inclined sides 5b serving as cutting edges, in the present embodiment, a pair. Since the groove bottom surface 4a of the serration groove 4 rises to a position closer to the gently sloping side 5a and the wall thickness is ensured, the strength of the land 5 is improved on the tooth tip side and the tooth base side, thereby causing the occurrence of chipping or the like. Can be prevented. On the other hand, since the groove depth is increased from the tooth tip to the tooth root between the steeply inclined side 5b and the step 4c sandwiching the serration groove 4, a pair of gently inclined sides that are used as cutting edges The chips generated by the 5a and the steeply inclined side 5b can be discharged smoothly, and the cutting oil supplied at the time of the shaving process 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 gently inclined side 5a of the land 5 is formed on the tooth surface 3 as described above. The serration groove 4 along the steeply inclined side 5b is formed so as to extend between the tooth tip and the tooth root of the tooth 2 so as to intersect each other, and a pair of gently inclined sides 5a and a pair of Since the steeply inclined sides 5b are parallel to each other, it is relatively easy to manufacture a shaving cutter in which serration grooves extend obliquely in one direction only by performing twice at different inclination angles α and β. Can do.

  At this time, the serration groove 4 along the gently inclined side 5a and the serration groove 4 along the steeply inclined side 5b have different groove depths. Since the step 4c is formed on the extended line of the side along the shaving cutter, the thickness is ensured on the tooth tip side and the tooth base side as described above, and the groove depth is increased between the step 4c, Again, it can be manufactured relatively easily.

  Furthermore, in the present embodiment, the groove bottom surface 4a composed of the serration groove 4 along the gently inclined side 5a and the serration groove 4 along the steeply inclined side 5b becomes an involute curve formed by the tooth surface 3 in the land 5 of the tooth 2. The gently sloping side 5a, which is a cutting edge, extends backward and substantially parallel to the groove wall surface 4b from the groove bottom surface 4a to the tooth surface 3 so as to be perpendicular to the groove bottom surface 4a and the tooth surface 3. And the steeply inclined side 5b 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 further to a pair of the gently inclined side 5a and the steeply inclined side 5b which are the cutting edges of the land 5. Sharp sharpness can be ensured.

  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 uneven hexagonal shape of the tooth surface 3 of the land 5 by the pair of steeply inclined sides 5a and 5b does not change after re-polishing.

  In the manufacturing method of the above embodiment, the step 4c is formed in the shaving cutter of the above embodiment by making the serration groove 4 along the steeply inclined side 5b deeper than the serrated groove 4 along the gently inclined side 5a. As viewed from the direction facing the surface 3, the land 5 extends on the extension line of the pair of steeply inclined sides 5 b, but conversely, the serration groove 4 along the gently inclined side 5 a is changed to the steeply inclined side 5 b. If the depth of the serration groove 4 is increased, the step 4c extends on the extended line of the gently inclined side 5a, and the serration groove 4 having the stepped groove-like groove bottom surface 4a is formed between them. it can.

  Also in the shaving cutter manufactured in this way, the thickness can be secured at the portion of the land 5 that is continuous with the steeply inclined side 5b from the groove bottom surface 4a on the tooth tip side and the tooth root side, so that the strength can be improved. At the same time, 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 oppositely inclined side edges 5a extending at an inclination angle α with respect to a direction perpendicular to the two tooth traces, and each of these gentle inclination sides 5a crossing an obtuse angle and being larger than the inclination angle α. A steeply inclined side 5b that forms a pair of opposite sides extending in a direction perpendicular to the streak of the tooth 2 in the same direction as the gently inclined side 5a at an inclination angle β, and a tooth tip side and a tooth root side of the tooth 2 6 shaving cutters having an eccentric hexagonal shape surrounded by a pair of opposite sides 5c extending in the direction of the tooth traces located at the same position were manufactured. Let these be Examples 1-6.

  Of the first to sixth embodiments, in the first, third, and fourth embodiments, the ratio between the maximum land width L and the minimum land width l in the tooth trace direction of the land 5 (hereinafter referred to as a land ratio) L / l. Is more than 1.2 and less than 1.8. Moreover, in Example 1, 2, with respect to the tooth height H between the pair of end sides 5c of the land 5, the land width is the maximum land width L from the end side 5c on the tooth base side of the pair of end sides 5c. The distance (hereinafter referred to as the position of the maximum land portion) h formed by the distance in the tooth height direction to a certain position (hereinafter referred to as the tooth height ratio) h / H is more than 0.2 and less than 0.7. It is said that. Furthermore, the inclination angle α was set equal to 3 ° in Examples 1 to 6.

  On the other hand, as a comparative example with respect to Examples 1 to 6, the land ratio L / l and the tooth height ratio h / H are equal to those of Examples 1 to 6, respectively, and the gently inclined side 5a is inclined at an inclination angle α = 0 °, that is, the tooth trace. The inclination angle β of the steeply inclined side 5b is equal to the difference β−α between the inclined angles α and β of the gently and steeply inclined sides 5a and 5b in the first to sixth embodiments. A shaving cutter was manufactured. These are referred to as Comparative Examples 1 to 6 corresponding to those in which the land ratio L / l, the tooth height ratio h / H, and the difference β-α between the inclination angles α and β are equal to those in Examples 1 to 6, respectively.

  Further, in Examples 1 to 6, Examples 2, 5, and 6 have the same land ratio L / l, tooth height ratio h / H, and inclination angles α and β with a difference β-α, except for the gently inclined side 5a. Three shaving cutters with a large inclination angle α of 6 ° were manufactured. These are referred to as Examples 7 to 9 in the order of the land ratio L / l, the tooth height ratio h / H, and the difference β−α between the inclination angles α and β being the same as those in Examples 2, 5, and 6. Therefore, in Examples 7 to 9, the inclination angle β of the steeply inclined side 5b is also larger than those in Examples 2, 5, and 6.

  Then, with the shaving cutters of Examples 1 to 9 and Comparative Examples 1 to 6, shaving is performed on the work gear under the same conditions, and the tooth profile error at that time is measured, and the presence or absence of the land 5 is confirmed. did. 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. The ratio h / H, the inclination angle α (°) of the gently inclined side 5a, the inclination angle β (°) of the steeply inclined side 5b, and the difference β−α (°) between the inclined angles α and β of the gently inclined sides 5a and 5b. The results are shown in Table 1.

  The specifications of the shaving cutter other than these are as follows. The cutter body 1 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 effect of the land ratio L / l and the tooth height ratio h / H, no groove is formed on the groove bottom surface 4a of the serration groove 4, and the groove depth is 0.68 mm. .

  The specifications of the gear to be cut are made of hardened steel with an outer diameter of 47.5 mm, a module 3.0, 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, first to sixth Examples 1 to 6 and Comparative Examples 1 to 6 having the same land ratio L / l, tooth height ratio h / H, and inclination angles α and β difference β−α are compared. In any of the combinations, the gently inclined side 5a is inclined in the same direction as the steeply inclined side 5b with respect to Comparative Examples 1 to 6 in which the gently inclined side 5a is perpendicular to the tooth line and is not inclined. It can be seen that Examples 1 to 6 have smaller tooth profile errors. In all of Examples 1 to 6 and Comparative Examples 1 to 6, there was no land ratio L / l of 1.8 or more, and the land 5 was not chipped.

  Further, when comparing Examples 1 to 6 in which the gently inclined side 5a is inclined in the same direction as the steeply inclined side 5b at the same inclination angle α, the land ratio L / l is more than 1.2 and less than 1.8. In Examples 1 to 4, which satisfy at least one of the range in which the tooth height ratio h / H is more than 0.2 and less than 0.7, the tooth profile error is 4 μm or less, which is 0 of the old JIS (JIS B 1702: 1960). In Example 1 that satisfies the class (4 μm or less), and in particular, that satisfies both, the tooth profile error was 3 μm, and high tooth profile accuracy could be obtained. Also, in Examples 5 and 6 that do not satisfy both of these ranges, the tooth profile error does not satisfy the former JIS class 0, but satisfies the class 1 (6 μm or less), and the tooth profile accuracy as a product gear is I was satisfied.

  Further, in the second and fifth embodiments, the land ratio L / l, the tooth height ratio h / H, and the difference β−α between the inclination angles α and β are equal to each other, and the inclination angles α and β of the steep and inclined sides 5a and 5b are different. 6 and Examples 7 to 9 show that Examples 7 to 9 having large inclination angles α and β both have high tooth profile accuracy. In particular, as described above, Examples 5 and 6 had old JIS class 1 tooth profile errors, whereas these Examples 5 and 6 had land ratio L / l, tooth height ratio h / H, and inclination angle α. In Examples 8 and 9, in which the difference β-α of β was equal and the inclination angle α was 6 °, which was twice, the results satisfied the 0 grade of the old JIS.

  However, if the inclination angle α of the gently inclined side 5a becomes too large, the intersection angle between the gently inclined side 5a and the end side 5c becomes small as can be seen from FIG. There is a possibility that the strength of the land 5 at the intersecting portion is impaired and chipping occurs. On the other hand, when the inclination angle α of the gently inclined side 5a becomes too small and approaches 0 °, it becomes the same as the shaving cutters of Comparative Examples 1 to 6, and higher tooth profile accuracy cannot be obtained.

  For this reason, it is desirable that the inclination angle α of the gently inclined side 5a be in the range of 3 ° to 6 ° as in the first to ninth embodiments. Further, the inclination angle β of the steeply inclined side 5b is such that the land ratio L / l is more than 1.2 and less than 1.8 and the tooth height ratio h / H is less than 1.8 with respect to the inclination angle α of the gently inclined side 5a. It is desirable to set a range that satisfies at least one of a range that is greater than 0.2 and less than 0.7, and more preferably a range that satisfies both.

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

Claims (7)

  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, the land has a hexagonal shape 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. A pair of gently sloping sides that are opposite to each other and that are opposite to each other, and that are inclined with respect to a direction perpendicular to the tooth traces of the teeth, and the looseness with respect to a direction perpendicular to the tooth traces of the teeth. A pair of steeply inclined sides extending in the same direction as the inclined side at an inclination angle larger than the gently inclined side, and positioned on the tooth tip side and the tooth base side of the tooth toward the tooth trace direction The teeth of the teeth surrounded by a pair of extending edges Shaving cutter, characterized in that the land width of the tooth trace direction forms a gradually becomes smaller polarized hexagonal toward the side and the tooth root side.   The pair of gently inclined sides and the pair of steeply inclined sides extend in parallel to each other when viewed from the direction facing the tooth surface perpendicular to the surface passing through the center of the tooth thickness direction of the tooth. The shaving cutter according to claim 1, wherein   3. The land width according to claim 1, wherein the ratio L / l of the maximum land width L to the minimum land width l is in a range of more than 1.2 and less than 1.8. Shaving cutter.   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 any one of claims 1 to 3, wherein the shaving cutter is provided.   The groove bottom surface of the serration groove is formed with a step extending on the extension line of the pair of gently inclined sides or the pair of steeply inclined sides when viewed from the direction facing the tooth surface, and the groove depth between the steps is groove depth. The shaving cutter according to any one of claims 1 to 4, wherein the shaving cutter has a stepped shape with a deep depth.   The method for manufacturing a shaving cutter according to any one of claims 1 to 5, wherein a serration groove along the gently inclined side and a serration groove along the steeply inclined side are formed on the tooth surface. Is formed between the tooth tip and the tooth root so as to cross each other.   A groove bottom surface composed of a serration groove along the gently inclined side and a serration groove along the steeply inclined side extends and retracts substantially parallel to the involute curve formed by the tooth surface of the tooth. 7. The method of manufacturing a shaving cutter according to claim 6, wherein a groove wall surface extending from the tooth surface to the tooth surface is formed to be perpendicular to the groove bottom surface and the tooth surface.

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