JP2010082786A

JP2010082786A - Hob cutter and method for manufacturing gear

Info

Publication number: JP2010082786A
Application number: JP2008257576A
Authority: JP
Inventors: Kazutaka Kobayashi; 一隆小林; Shinichi Harada; 信一原田; Kenichi Sonowa; 憲一其輪
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 2008-10-02
Filing date: 2008-10-02
Publication date: 2010-04-15

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently discharge chips produced in the manufacture of a gear by a hob cutter. <P>SOLUTION: External teeth 5 are formed with a hob cutter 1 on the outer circumferential face of an internal gear 3 in a planetary gear used in an automatic transmission for automobiles. The hob cutter 1 has a hob teeth 11 spirally formed and comprises a plurality of divided auxiliary hob teeth 11a formed by dividing the hob teeth 11 into a plurality of parts along the spiral direction. Grooves 21 along the spiral direction are formed on a flank 17 on the outer circumferential face of each of the divided auxiliary hob teeth 11a. The grooves 21 cut chips, produced in the manufacture of a gear by the hob cutter 1, into pieces. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、ホブカッタ及びホブカッタによる歯車の製造方法に関する。 The present invention relates to a hob cutter and a gear manufacturing method using the hob cutter.

ホブカッタやブローチ工具（下記特許文献１）などで、ワークに対して切削あるいは成形加工を行う際には切り屑が排出されるが、この切り屑を効率よく排出することで、加工効率を高めることができる。
特開平７−１９５２２９号公報 Chips are discharged when cutting or forming a workpiece with a hob cutter or broach tool (Patent Document 1 below). By efficiently discharging the chips, the processing efficiency is increased. Can do.
JP 7-195229 A

ところで、ホブカッタで歯車を製造する際の切り屑は、螺旋状に形成されたホブ歯の軸方向相互間の隙間、すなわちホブカッタの歯底と被削歯車の刃先との間の隙間から排出される。 By the way, chips when the gear is manufactured by the hob cutter are discharged from the gap between the axial directions of the hob teeth formed in a spiral shape, that is, the gap between the tooth bottom of the hob cutter and the cutting edge of the work gear. .

このため、特に上記したホブカッタの歯底と被削歯車の刃先との間の隙間が狭いと、この狭い隙間に切り屑が詰まる恐れがあり、切り屑を効率よく排出することができなくなって加工効率の低下を招く。また、隙間に切り屑が詰まると、被削歯車の刃先に切り屑が咬み込み、被削歯車を損傷させることになる。 For this reason, in particular, if the gap between the tooth bottom of the hob cutter and the cutting edge of the gear to be cut is narrow, there is a possibility that chips are clogged in the narrow gap, and the chips cannot be efficiently discharged and processed. It causes a decrease in efficiency. Further, when chips are clogged in the gap, the chips bite into the cutting edge of the work gear and damage the work gear.

そこで、本発明は、ホブカッタによる歯車の製造時に発生する切り屑を効率よく排出できるようにすることを目的としている。 Therefore, an object of the present invention is to enable efficient discharge of chips generated during the manufacture of a gear by a hob cutter.

本発明は、ホブカッタによって形成する歯車の歯底に対応するホブ歯の逃げ面に、ホブ歯の螺旋方向に沿う溝を設けたことを特徴とする。 The present invention is characterized in that a groove along the spiral direction of the hob tooth is provided on the flank face of the hob tooth corresponding to the tooth bottom of the gear formed by the hob cutter.

本発明によれば、ホブ歯によりワークの表面を切削する際に排出される切り屑を、歯車の歯底に対応する面に形成されかつホブ歯の螺旋方向に沿う溝により分断することができる。これにより、ホブカッタの歯底と被削歯車の刃先との間の隙間が狭い場合であっても、この狭い隙間に切り屑が詰まることを抑制して、切り屑を効率よく排出することができ、被削歯車の刃先に切り屑が咬み込むことによる被削歯車の損傷を抑えることができる。 According to the present invention, the chips discharged when cutting the surface of the workpiece with the hob teeth can be divided by the grooves formed on the surface corresponding to the tooth bottom of the gear and along the spiral direction of the hob teeth. . As a result, even when the gap between the bottom of the hob cutter and the cutting edge of the work gear is narrow, it is possible to prevent chips from clogging in the narrow gap and efficiently discharge the chips. In addition, it is possible to suppress damage to the work gear due to chips biting into the cutting edge of the work gear.

以下、本発明の実施の形態を図面に基づき説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

図１に正面図及び図２に図１の左側面図として示すホブカッタ１は、例えば自動車の自動変速機に使用される遊星歯車装置の図３に示す歯車としてのインターナルギア３の外周面に対して外歯５を形成する際に使用する。 A hob cutter 1 shown in FIG. 1 as a front view and in FIG. 2 as a left side view of FIG. 1 is based on an outer peripheral surface of an internal gear 3 as a gear shown in FIG. 3 of a planetary gear device used for an automatic transmission of an automobile, for example. And used when forming the external teeth 5.

上記インターナルギア３は、環状に形成されてその内周面に遊星歯車装置のプラネタリギアが噛み合う内歯７を備え、外周面の前記した外歯５は、自動変速機のハウジングに固定するためのものである。この外歯５の円周方向に沿って複数形成される歯９は、ほぼ直方体形状を呈している。 The internal gear 3 is formed in an annular shape and has inner teeth 7 with which the planetary gear of the planetary gear device meshes with the inner peripheral surface thereof, and the outer teeth 5 on the outer peripheral surface are fixed to the housing of the automatic transmission. Is. A plurality of teeth 9 formed along the circumferential direction of the external teeth 5 have a substantially rectangular parallelepiped shape.

ホブカッタ１は、ホブ歯１１の全体が螺旋状に形成され、その外周部に軸線方向（図１中で左右方向）に沿って延びる軸方向溝１３を円周方向等間隔に複数設けてあり、これによりホブ歯１１は、図２に示すように螺旋方向に沿って互いに離間するように、複数に分断される分断ホブ歯１１ａを形成している。この各分断ホブ歯１１ａには、ホブ歯１１の回転方向（図２の矢印Ａで示す方向）前方にすくい面（工具研削面）１５を備えるとともに、外周面に逃げ面１７を備えている。 In the hob cutter 1, the entire hob teeth 11 are formed in a spiral shape, and a plurality of axial grooves 13 extending along the axial direction (left-right direction in FIG. 1) are provided on the outer periphery thereof at equal intervals in the circumferential direction. As a result, the hob teeth 11 form divided hob teeth 11a that are divided into a plurality of pieces so as to be separated from each other along the spiral direction as shown in FIG. Each of the divided hob teeth 11a is provided with a rake face (tool grinding surface) 15 in front of the rotation direction of the hob teeth 11 (direction indicated by arrow A in FIG. 2) and a flank 17 on the outer peripheral surface.

そして、上記したホブ歯１１の逃げ面１７に、ホブ歯１１の螺旋方向に沿う溝２１を設けている。すなわち、このホブカッタ１は、歯車であるインターナルギア３における歯９の歯底２３に対応するホブ歯１１の逃げ面１７に、ホブ歯１１の螺旋方向に沿う溝２１を設けたことになる。 And the groove | channel 21 in alignment with the spiral direction of the hob tooth 11 is provided in the flank 17 of the hob tooth 11 mentioned above. That is, the hob cutter 1 is provided with the groove 21 along the spiral direction of the hob tooth 11 on the flank 17 of the hob tooth 11 corresponding to the root 23 of the tooth 9 in the internal gear 3 that is a gear.

ここで、分断ホブ歯１１ａは、図２に示すように、円周方向に沿って偶数個備えており、この偶数個の分断ホブ歯１１ａに対し、溝２１を１個設けた分断ホブ歯１１ａと、溝２１を２個設けた分断ホブ歯１１ａとを、円周方向（螺旋方向）に沿って交互に設定している。 Here, as shown in FIG. 2, the divided hob teeth 11a are provided with an even number along the circumferential direction, and the divided hob teeth 11a provided with one groove 21 for the even number of divided hob teeth 11a. And the divided hob teeth 11a provided with two grooves 21 are alternately set along the circumferential direction (spiral direction).

さらに、上記１個の溝２１は、２個の溝２１に対し、軸方向の位置として中間位置に設定してある。すなわち、螺旋方向に沿って互いに隣接する各分断ホブ歯１１ａに設けた１個の溝２１と２個の溝２１とは、ホブカッタ１の軸方向（図１中で左右方向）に沿って互いにずれていることになる。 Further, the one groove 21 is set at an intermediate position as an axial position with respect to the two grooves 21. That is, the one groove 21 and the two grooves 21 provided in the respective divided hob teeth 11a adjacent to each other along the spiral direction are shifted from each other along the axial direction (left and right direction in FIG. 1) of the hob cutter 1. Will be.

なお、溝２１の断面形状は、ここでは図４（ａ）に示すように円弧（凹曲面）形状とするが、図４（ｂ）のようにＶ字形状の溝２１Ａや、図４（ｃ）のようにＵ字形状の溝２１Ｂであってもよい。円弧形状の溝２１は、図４（ｂ）のＶ字形状の溝２１Ａに対して、切り屑の一部が入り込む容積を大きく取りやすく、また図４（ｃ）のＵ字形状の溝２１Ｂに対して、角部の角度（α）が直角よりも大きな角度（鈍角）となっているので、工具磨耗関して有利でありホブカッタ１として高寿命化を達成できる。 Here, the cross-sectional shape of the groove 21 is an arc (concave surface) as shown in FIG. 4A, but the V-shaped groove 21A as shown in FIG. 4B or FIG. U-shaped groove 21B as shown in FIG. The arc-shaped groove 21 is easy to take a larger volume for a part of chips to enter than the V-shaped groove 21A of FIG. 4B, and the U-shaped groove 21B of FIG. On the other hand, since the angle (α) of the corner is larger than the right angle (obtuse angle), it is advantageous in terms of tool wear, and the life of the hob cutter 1 can be increased.

また、溝２１に代わる溝の断面形状として、図４（ｂ）のＶ字形状の溝２１Ａの先端（底部）にＲを付けた形状でもよい。 Further, as a cross-sectional shape of the groove in place of the groove 21, a shape in which R is attached to the tip (bottom) of the V-shaped groove 21A of FIG.

ここで、特に、図４（ａ）に示すように、溝２１の幅Ｗと溝２１の深さＨとの関係を、Ｗ＞Ｈとすることで、ホブ歯１１の逃げ面１７と溝２１の円弧との交点Ｐにおける円弧の接線Ｌと、逃げ面１７とがなす角度αをより確実に大きくすることができ、工具磨耗抑制により効果的である。 Here, in particular, as shown in FIG. 4A, by setting the relationship between the width W of the groove 21 and the depth H of the groove 21 to W> H, the relief surface 17 of the hob tooth 11 and the groove 21 are obtained. The angle α formed by the arc tangent L at the intersection P with the arc and the flank 17 can be increased more reliably, which is effective in suppressing tool wear.

また、図５に示すように、ホブカッタ１の各分断ホブ歯１１ａは、溝２１の底面２１ａを逃げ面１７に平行となるように、逃げ角βと同等の角度βだけ傾斜させてある。 Further, as shown in FIG. 5, each divided hob tooth 11 a of the hob cutter 1 is inclined by an angle β equivalent to the clearance angle β so that the bottom surface 21 a of the groove 21 is parallel to the clearance surface 17.

このようなホブカッタ１により、図６に示すワークＷの表面２５に対して歯切加工を行う際には、ホブカッタ１を図６中で左右方向の中心軸線を中心として回転させつつ、加工に伴ってホブカッタ１をワークＷの表面２５に向けて（図６中で上方に向けて）徐々に接近させる。 When gear cutting is performed on the surface 25 of the workpiece W shown in FIG. 6 with such a hob cutter 1, the hob cutter 1 is rotated around the central axis in the horizontal direction in FIG. The hob cutter 1 is gradually approached toward the surface 25 of the workpiece W (upward in FIG. 6).

ここで図６（ａ）は、溝２１を２個備えた分断ホブ歯１１ａで加工している状態を示しており、この際発生する切り屑２７は、２個の溝２１によってホブカッタ１の軸方向（図６中で左右方向）に沿って３つの分断切り屑２７ａ，２７ｂ，２７ｃに分断される。このとき、２個の溝２１によってワークＷの表面２５には２個の突起Ｗａが形成される。 Here, FIG. 6A shows a state where machining is performed by the divided hob teeth 11 a having two grooves 21, and the chips 27 generated at this time are formed on the shaft of the hob cutter 1 by the two grooves 21. The cut pieces 27a, 27b, and 27c are divided along the direction (left and right direction in FIG. 6). At this time, two protrusions Wa are formed on the surface 25 of the workpiece W by the two grooves 21.

また、図６（ｂ）は、上記溝２１を２個備えた分断ホブ歯１１ａに対し、ホブカッタ１の回転方向後方側に位置する、溝２１を１個備えた分断ホブ歯１１ａでの加工状態を示している。すなわち、この溝２１を１個備えた分断ホブ歯１１ａでは、切り屑２７を２つの分断切り屑２７ｄ，２７ｅに分断する。このとき、１個の溝２１によってワークＷの表面２５には１個の突起Ｗｂが形成されるが、１個の溝２１は、前記した２個の溝２１に対してホブカッタ１の軸方向（図６中で左右方向）にずれているので、図６（ａ）にて２個の溝２１によって形成された２個の突起Ｗａは削除される。 Further, FIG. 6B shows a machining state of the divided hob tooth 11a having one groove 21 located on the rear side in the rotation direction of the hob cutter 1 with respect to the divided hob tooth 11a having two grooves 21. Is shown. That is, in the divided hob tooth 11a having one groove 21, the chips 27 are divided into two divided chips 27d and 27e. At this time, one projection Wb is formed on the surface 25 of the workpiece W by one groove 21, but one groove 21 is in the axial direction of the hob cutter 1 with respect to the two grooves 21 ( Since it is shifted in the horizontal direction in FIG. 6, the two protrusions Wa formed by the two grooves 21 in FIG. 6A are deleted.

以上のようなホブ歯１１による加工を行う際のホブ歯１１の切り込み量Ｍは、溝２１の深さＨよりも小さくすることで、切り屑２７の分断をより確実なものとする。 The cutting amount M of the hob teeth 11 when processing with the hob teeth 11 as described above is made smaller than the depth H of the groove 21, so that the cutting pieces 27 are more reliably divided.

このように切り屑２７を分断切り屑２７ａ，２７ｂ，２７ｃあるいは分断切り屑２７ｄ，２７ｅとして小さくすることで、この分断切り屑２７ａ，２７ｂ，２７ｃあるいは分断切り屑２７ｄ，２７ｅを、ホブカッタ１の歯底２９とインターナルギア３に形成した歯９の先端との間の隙間から容易に排出することができる。 Thus, by making the chip 27 small as the divided chips 27a, 27b, 27c or the divided chips 27d, 27e, the divided chips 27a, 27b, 27c or the divided chips 27d, 27e are used as the teeth of the hob cutter 1. It can be easily discharged from the gap between the bottom 29 and the tip of the tooth 9 formed on the internal gear 3.

この結果、ホブカッタ１の歯底２９と被削歯車の刃先（歯の先端）との間の隙間が狭い場合であっても、この狭い隙間に対しても切り屑２７が詰まることを抑制して切り屑２７を効率よく排出することができ、加工速度も向上して加工効率を高めることができる。また、上記した隙間に対する切り屑２７の詰まりを抑制することで、インターナルギア３に形成した歯９の先端への切り屑の咬み込みを抑制し、インターナルギア３の損傷を抑制することができる。 As a result, even if the gap between the tooth bottom 29 of the hob cutter 1 and the cutting edge (tooth tip) of the work gear is narrow, the clogging of the chips 27 is suppressed even in this narrow gap. The chips 27 can be discharged efficiently, the processing speed can be improved, and the processing efficiency can be increased. In addition, by suppressing clogging of the chips 27 with respect to the gaps described above, it is possible to suppress the biting of the chips into the tips of the teeth 9 formed on the internal gear 3 and to suppress damage to the internal gear 3.

また、本実施形態では、ホブ歯１１は螺旋方向に沿って互いに離間するように分断ホブ歯１１ａを複数備え、前記螺旋方向に沿って互いに隣接する各分断ホブ歯１１ａに設けた溝２１は、ホブカッタ１の軸方向に沿って互いにずれている。これにより、ホブカッタ１の回転方向前方の分断ホブ歯１１ａで切削後のワークの表面に残る突起Ｗａ（Ｗｂ）を、その回転方向後方の分断ホブ歯１１ａでの切削時に削除することができ、効率よい切削加工を行うことができる。 Further, in the present embodiment, the hob teeth 11 are provided with a plurality of divided hob teeth 11a so as to be separated from each other along the spiral direction, and the grooves 21 provided in the respective divided hob teeth 11a adjacent to each other along the spiral direction include: They are displaced from each other along the axial direction of the hob cutter 1. Thereby, the protrusion Wa (Wb) remaining on the surface of the workpiece after cutting by the divided hob teeth 11a in the front direction of rotation of the hob cutter 1 can be deleted at the time of cutting by the divided hob teeth 11a at the rear side of the rotation direction. Good cutting can be performed.

また、本実施形態では、軸方向に互いに隣接する螺旋状のホブ歯１１の先端相互の軸方向間隔Ｂが、ホブ歯１１によるインターナルギア３の歯９の形成時に発生する分断切り屑２７ａ，２７ｂ，２７ｃ，２７ｄ，２７ｅの軸方向に対応する長さよりも短く（狭く）なるように、切削条件やホブ歯１１の形状を設定する。 Further, in the present embodiment, the axial distance B between the tips of the helical hob teeth 11 adjacent to each other in the axial direction is the divided chips 27 a and 27 b generated when the teeth 9 of the internal gear 3 are formed by the hob teeth 11. , 27c, 27d, 27e, the cutting conditions and the shape of the hob teeth 11 are set so as to be shorter (narrower) than the length corresponding to the axial direction.

これにより、分断切り屑２７ａ，２７ｂ，２７ｃ，２７ｄ，２７ｅが、ホブ歯１１相互間の歯溝に入りやすくなり、切り屑２７をより効率よく排出することができる。 Thereby, the divided chips 27a, 27b, 27c, 27d, and 27e can easily enter the tooth gap between the hob teeth 11, and the chips 27 can be discharged more efficiently.

さらに、本実施形態では、図５に示すように、ホブ歯１１先端の逃げ面１７の逃げ角βに対し、溝２１の底面２１ａの傾斜角度を同等として、逃げ面１７と溝２１の底面２１ａとを互いに平行としている。 Furthermore, in this embodiment, as shown in FIG. 5, the inclination angle of the bottom surface 21a of the groove 21 is made equal to the clearance angle β of the clearance surface 17 at the tip of the hob teeth 11, and the clearance surface 17 and the bottom surface 21a of the groove 21 are used. Are parallel to each other.

これにより、すくい面１５を再研磨しても溝２１の深さを常に一定として変化を抑えることができ、再研磨後も切り屑２７に対する分断作用を継続して維持することができる。 Thereby, even if the rake face 15 is re-polished, the depth of the groove 21 can be kept constant and the change can be suppressed, and the cutting action on the chips 27 can be continuously maintained even after re-polishing.

なお、上記実施形態では、溝２１を１個設けた分断ホブ歯１１ａと、溝２１を２個設けた分断ホブ歯１１ａとを、円周方向（螺旋方向）に沿って交互に設定することで、螺旋方向に沿って互いに隣接する各分断ホブ歯１１ａの溝２１をホブ歯１１の軸方向にずらしているが、各分断ホブ歯１１ａに溝２１を１個ずつ設けて、これら各溝２１をホブ歯１１の軸方向にずらしてもよい。要するに、溝２１の数に関係なく、互いに隣接する各分断ホブ歯１１ａにおける溝２１が軸方向に互いにずれていればよい。 In the above embodiment, the divided hob teeth 11a provided with one groove 21 and the divided hob teeth 11a provided with two grooves 21 are alternately set along the circumferential direction (spiral direction). The grooves 21 of the divided hob teeth 11a adjacent to each other along the spiral direction are shifted in the axial direction of the hob teeth 11, and one groove 21 is provided in each divided hob tooth 11a. The hob teeth 11 may be shifted in the axial direction. In short, regardless of the number of grooves 21, it is only necessary that the grooves 21 in the adjacent divided hob teeth 11a are displaced from each other in the axial direction.

本発明の一実施形態を示すホブカッタの正面図である。It is a front view of the hob cutter which shows one Embodiment of this invention. 図１の左側面図である。It is a left view of FIG. 図１のホブカッタで外歯を形成するインターナルギアの斜視図である。It is a perspective view of the internal gear which forms an external tooth with the hob cutter of FIG. ホブカッタに設けた溝の断面形状図であり、（ａ）は円弧形状、（ｂ）はＶ字形状、（ｃ）はＵ字形状である。It is sectional drawing of the groove | channel provided in the hob cutter, (a) is circular arc shape, (b) is V-shaped, (c) is U-shaped. ホブカッタのホブ歯先端における軸線と直交する方向の断面図である。It is sectional drawing of the direction orthogonal to the axis line in the hob tooth front-end | tip of a hob cutter. ワークの表面に対して歯切加工を行っている状態を示す動作説明図で、（ａ）は溝を２個備えた分断ホブ歯により切り屑が３つに分断された状態を示し、（ｂ）は溝を１個備えた分断ホブ歯により切り屑をさらに分断した状態を示す。It is operation | movement explanatory drawing which shows the state which is performing the gear cutting process on the surface of a workpiece | work, (a) shows the state by which the chip was divided | segmented into three by the parting hob tooth provided with two grooves, (b ) Shows a state in which the chips are further divided by a divided hob tooth having one groove.

Explanation of symbols

Ｗワーク
１ホブカッタ
３インターナルギア（歯車）
９歯
１１ホブ歯
１１ａ分断ホブ歯
１７ホブ歯の逃げ面
２１ホブ歯の螺旋方向に沿う溝
２１ａ溝の底面
２３インターナルギアの歯底
２７切り屑
２７ａ，２７ｂ，２７ｃ，２７ｄ，２７ｅ分断切り屑 W Work 1 Hob cutter 3 Internal gear (gear)
9 teeth 11 hob teeth 11a split hob teeth 17 flank face of hob teeth 21 groove along spiral direction of hob teeth 21a bottom surface of groove 23 tooth bottom of internal gear 27 chips 27a, 27b, 27c, 27d, 27e divided chips

Claims

A hob cutter for manufacturing a gear by forming teeth on the surface of a workpiece, wherein a groove along the spiral direction of the hob tooth is provided on a flank of the hob tooth corresponding to the tooth bottom of the gear. .

The hob teeth are provided with a plurality of divided hob teeth so as to be separated from each other along the spiral direction, and the grooves provided in the divided hob teeth adjacent to each other along the spiral direction are along the axial direction of the hob cutter. The hob cutter according to claim 1, wherein the hob cutter is shifted from each other.

By making the axial interval between the tips of the spiral hob teeth adjacent to each other in the axial direction shorter than the length corresponding to the axial direction of the chips generated when the teeth are formed by the hob teeth, the chips The hob cutter according to claim 1, wherein the hob cutter is inserted between the tips of the hob teeth.

The hob cutter according to any one of claims 1 to 3, wherein a bottom surface of the groove is parallel to a clearance surface of the hob tooth tip surface.

A gear manufacturing method for manufacturing a gear by forming teeth on a surface of a workpiece by a hob cutter, wherein chips discharged when the surface of the workpiece is cut by a hob tooth corresponds to a tooth bottom of the gear. A method for manufacturing a gear, characterized in that the gear is divided by a groove formed on the flank and along the spiral direction of the hob teeth.