JP5228969B2 - Phrasing cutter - Google Patents

Description

  The present invention particularly relates to a phrasing cutter that uses a helical gear as a workpiece gear and chamfers the workpiece by meshing with the helical gear and pressing an edge of the tooth surface in the direction of the teeth.

  A framing cutter (chamfering tool) used for chamfering the edge of a tooth surface of a gear that has been gear-cut is usually formed by coaxially combining a pair of cutter bodies having gear-shaped machining teeth via a spacer or the like. The cutting teeth of these cutter bodies are fed while rotating so as to mesh with both edges of the tooth surface of the tooth surface of the gear to be machined. Is pressed and crushed, that is, the edge is chamfered by plastic deformation by rolling. For example, Patent Document 1 describes that a helical gear is chamfered as a workpiece gear by such a phrasing cutter.

Japanese Patent No. 3816837

  By the way, since the processing with such a phrasing cutter is to chamfer the edge by plastic deformation by rolling as described above, the chamfered edge portion is deformed so as to spread to the periphery to generate burrs. Sometimes. However, among these, what spreads on the end face of the gear to be machined can be easily removed by cutting with a cutting tool or the like, and what spread on the tooth face of the machined gear can be removed by machining with a shaving cutter.

  However, if the edge part deformed in this way spreads to the tooth base side of the processed gear to generate burrs, it is not easy to remove it. In particular, when the gear to be machined is a helical gear, the teeth are diagonally aligned with an acute side edge where the edge of the tooth surface in the direction of the tooth streak forms an acute angle and an obtuse angle side edge which forms an obtuse angle. Among them, since the chamfering amount is increased at the acute angle side edge, the deformation of the edge chamfered in this way also tends to generate burrs on the tooth base side.

  The present invention has been made under such a background. In a phrasing cutter in which a helical gear is used as a machined gear and a chamfer is formed at the edge of the tooth surface in the tooth line direction, the machined machine is particularly suitable for a helical gear. It is an object of the present invention to provide a phrasing cutter capable of suppressing the occurrence of burrs on the tooth base side at an acute angle side edge.

  In order to solve the above-mentioned problems and achieve such an object, the present invention engages with the helical gear to be machined and presses the edge of the tooth surface of the helical gear in the direction of the teeth. This is a phrasing cutter that chamfers by pressing the sharp-side processed tooth surface and the obtuse-angle side edge that press the sharp-side edge of the helical gear teeth on the outer peripheral surface of the disc-shaped cutter body. A gear-shaped machining tooth having an obtuse-angle-side machining tooth surface, wherein the acute-angle-side machining tooth surface is a reference surface obtained by extending the acute-angle side machining tooth surface on the tooth base side at the tooth tip side of the machining tooth. On the other hand, it is retracted in the tooth thickness direction of the processed tooth.

  That is, in such a phrasing cutter, the tooth surface of the machined tooth that chamfers the edge of the helical gear to be machined is a standard that normally forms an involute tooth profile so that the machined tooth meshes with the tooth of the machined gear. However, in the phrasing cutter having the above-described configuration, the sharp-side processed tooth surface chamfered by pressing the sharp-angle side edge of the helical gear among the tooth surfaces of the processed tooth While it is formed along the reference surface on the base side of the processed tooth, it is retracted in the tooth thickness direction so as to escape from the reference surface on the tooth tip side.

  Therefore, when chamfering of a helical gear to be machined by such a phrasing cutter, at the acute angle side edge of the tooth to be machined, the tooth tip side of the machined tooth, that is, the machined tooth is the root of the tooth of the helical gear. On the other hand, the chamfering amount can be reduced as compared with the case where the chamfering is performed with the processing tooth surface as it is, and the deformation of the acute side edge due to the chamfering can be suppressed. For this reason, it is possible to prevent the deformed sharp edge portion from spreading greatly to the tooth root side of the helical gear and to generate burrs, and to be chamfered with high accuracy. Can do.

  Here, it is desirable that the acute-side machining tooth surface is retracted from the reference surface on the tooth tip side with respect to the pitch circle of the machining tooth, that is, on the tooth root side of the machining tooth with respect to the pitch circle. It is desirable that the acute-side processed tooth surface is formed on the reference surface. If the acute-angle side machining tooth surface recedes on the tooth root side of the machining tooth from the pitch circle, there is a possibility that chamfering of the sharp-angle side edge of the helical gear is insufficient in the helical gear.

  Further, the acute angle side processing tooth surface may be retracted on the tooth tip side, for example, by cutting out the tooth tip side of the reference surface by a flat surface, but has a convex curved surface shape having a circular arc shape in cross section. By forming it so as to be retracted with respect to the reference surface, the joint portion with the portion along the reference surface is prevented from being angular, and the workpiece is chamfered at the acute angle side edge of the helical gear. The shape can be processed to high quality.

  Furthermore, at the tooth tip of the processed tooth, the retraction amount of the acute angle side processed tooth surface with respect to the reference surface is (0.4 to the chamfer width b of the acute angle side edge of the tooth of the helical gear. ˜0.8) × b, and if the retraction amount is smaller than this range, the workpiece is insufficiently restrained from deforming the sharp edge of the helical gear, and the tooth root While it may not be possible to suppress the occurrence of burrs on the side, if the amount of retraction is large enough to exceed this range, the strength of the machined tooth may be impaired on the tooth tip side depending on the thickness of the machined tooth itself. There is a fear.

  As described above, according to the present invention, in the chamfering process by the phrasing cutter, it is possible to suppress the occurrence of burrs on the tooth base side at the acute angle side edge of the tooth surface of the helical gear, Thereby, it is possible to perform chamfering with high accuracy and high quality without removing such burrs in a subsequent process.

It is a figure which shows the chamfering process of the helical gear which is to be processed by the phrasing cutter of one embodiment of the present invention. FIG. 2 is a perspective view showing a state where the processing teeth of the phrasing cutter are engaged with the teeth of a helical gear in FIG. 1. FIG. 2 is a sectional view taken along a pitch circle showing a state in which the processing teeth of the phrasing cutter are chamfering the edges of the teeth of the helical gear to be processed in FIG. 1. It is sectional drawing along the tooth thickness direction of the processing tooth in the phrasing cutter of embodiment shown in FIG.

  In the phrasing cutter of this embodiment, as shown in FIG. 1, a plurality of processing teeth 2 are integrally formed in a gear shape on the outer peripheral surface of a disc-shaped cutter main body 1, and a pair of such cutter main bodies 1 are provided. The workpieces are integrally assembled so as to be coaxial with each other with a predetermined interval corresponding to the tooth width of the helical gear 11 through a spacer 3 having a disk shape smaller in diameter than the cutter body 1. It is configured.

  Further, the phrasing cutter assembled in this way has both the tooth surfaces 4 and 5 of the machining teeth 2 of the pair of cutter bodies 1 and the tooth surfaces 13 of the teeth 12 of the helical gear 11 to be machined. The above-mentioned workpiece that is meshed so as to be in contact with the edges 14 and 15 in the streak direction and is rotated around the axis O that is coaxial with the axis O while being rotated around the axis C that is parallel to the axis O. By feeding the helical gear 11 side, the end edges 14 and 15 are pressed and chamfered.

  Here, since the workpiece to be machined is the helical gear 11 in the present embodiment, the tooth 12 has a helical winding shape, and therefore the end edges 14 and 15 of the tooth surface 13 are tooth surfaces. An acute angle side edge 14 that intersects the end surface 16 of the tooth 12 with an acute angle and an obtuse angle side edge 15 that intersects with the obtuse angle diagonally in a cross section along the pitch circle of the tooth 12 as shown in FIG. Will be located. On the other hand, in this embodiment, as shown in FIG. 3, of the machined tooth surfaces 4 and 5 of the machined tooth 2, the acute-side machined tooth surface is chamfered in contact with the acute-side edge 14. The obtuse-angle-side processed tooth surface 5 is chamfered in contact with the obtuse-angle side edge 15.

  In the present embodiment, the acute-side processed tooth surface 4 is formed so as to extend in parallel to the axis O in the direction of the axis O of the cutter body 1, whereby the acute-side edge 14 is also processed. The helical gear 11 is chamfered in the direction of the axis C in parallel with the axis C. On the other hand, the obtuse-angle-side processed tooth surface 5 is inclined with respect to the axis O of the cutter body 1 so that the tooth surface 13 of the helical gear 11 is slightly larger than the angle formed with respect to the axis C. The obtuse angle side edge 15 is chamfered so as to intersect the tooth surface 13 and the end surface 16 at an obtuse angle in accordance with the angle of the obtuse angle side processed tooth surface 5.

  The pair of cutter bodies 1 are substantially the same shape and the same size, but the acute angle side machining tooth surface 4 and the obtuse angle side machining tooth surface 5 of the machining tooth 2 are opposite to each other in the circumferential direction. The processing teeth 2 between these cutter bodies 1 are arranged so that the tooth thickness thereof decreases toward the other cutter body 1 side in the axis O direction (toward the spacer 3 side). In addition, the machining teeth 2 of the pair of cutter bodies 1 can be chamfered by contacting the pair of acute side edges 14 and the obtuse side edges 15 of the teeth 12 of the helical gear 11 to be machined. The circumferential phase is shifted and assembled.

  Further, the machining teeth 2 of the pair of cutter main bodies 1 are such that the acute angle side machining tooth surface 4 is on the tooth root side on the tooth tip side (upper side in FIG. 4) of the machining tooth 2 as shown in FIG. With respect to the reference surface S obtained by extending the acute angle side processing tooth surface 4 (lower side in FIG. 4), the processing tooth 2 is retracted in the tooth thickness direction. In addition, what is indicated by a symbol P in the drawing is a pitch circle of a gear formed by the machining teeth 2 of the cutter body 1, and the acute-side machining tooth surface 4 is a reference surface S on the tooth tip side of the pitch circle P. And is formed along the reference plane S on the tooth root side from the pitch circle P.

  That is, the processing tooth 2 of such a phrasing cutter is normally engaged with the tooth 12 of the helical gear 11 so that the end edges 14 and 15 thereof are in contact with the processing tooth surface. Are formed along the reference surface S which forms an involute tooth profile corresponding to the involute tooth profile formed by the involute tooth profile. Although it is formed along the reference surface S, the tooth thickness is such that, on the tooth tip side of the acute angle side processed tooth surface 4, it escapes from the reference surface S that is an extension of the acute angle side processed tooth surface 4 on the tooth base side. It is retracted so as to be recessed in the direction.

  Here, in the present embodiment, the tooth tip side of the acute-side processed tooth surface 4 has a convex curved surface shape that forms a convex arc in a cross section orthogonal to the axis O of the cutter body 1, for example, as shown in FIG. Therefore, the retraction amount from the reference surface S is gradually increased toward the tooth tip side. In addition, the tooth tip side of the acute angle side processing tooth surface 4 retreated in this way and the tooth base side along the reference surface S are connected so as to be smoothly connected.

  Further, the retraction amount Q at the tooth tip of the machining tooth 2 of the acute-side machining tooth surface 4 thus retreated, that is, the position when the acute-side machining tooth surface 4 is formed along the reference surface S up to the tooth tip, and the retraction. In the present embodiment, the distance in the tooth thickness direction from the position of the tooth tip of the acute angle side processed tooth surface 4 is (0) with respect to the chamfer width b of the acute side edge 14 of the tooth 12 of the helical gear 11 to be processed. .4 to 0.8) × b. However, in this embodiment, as shown in FIG. 4, the position of the tooth tip of the acute-side machining tooth surface 4 retreated in this way is the position of the machining tooth 2 when the acute-side machining tooth surface 4 is formed along the reference surface S. The center line R in the tooth thickness direction is not exceeded.

  When the chamfering of the helical gear 11 is performed by the phrasing cutter configured in this manner, the obtuse angle side machining tooth surface 5 along the reference surface S and the tooth base side of the acute angle side machining tooth surface 4 are conventional. In the same manner as above, these processed tooth surfaces 5 and 4 are crushed by abutting and pressing the obtuse angle side edge 15 and the acute angle side edge 14 of the helical gear 11 to be machined, thereby obtaining a predetermined chamfer. Although the chamfering is performed by the amount, the chamfering amount decreases because the acute-side machining tooth surface 4 recedes from the reference surface S on the tooth tip side of the acute-side machining tooth surface 4.

  For this reason, in particular, the workpiece 14 can be chamfered by suppressing the edge 14 that has been crushed at the acute-side edge 14 where the chamfering amount increases in the helical gear 11 from spreading to the root side of the tooth 12. It is possible to prevent a situation in which burrs are generated at the base of the teeth 12. Therefore, according to the framing cutter having the above-described configuration, it is possible to chamfer the helical gear 11 with high accuracy and high quality, and post-processing for removing such burrs on the tooth base side. This eliminates the need for simplification of the gear manufacturing process.

  Further, in the present embodiment, the acute angle side processing tooth surface 4 is retracted from the reference surface S on the tooth tip side with respect to the pitch circle P of the processing tooth 2, that is, at least from the pitch circle P to the tooth root side. Then, the acute-angle side processed tooth surface 4 is formed along the reference surface S. For this reason, the workpiece can be chamfered with the necessary chamfering amount reliably maintained on the tooth tip side of the tooth 12 of the helical gear 11.

  Furthermore, in this embodiment, the tooth tip side of the acute angle side machining tooth surface 4 thus retreated has a convex curved surface as described above, and the tooth root side of the acute angle side machining tooth surface 4 along the reference surface S. As a result, it is possible to smoothly connect the connecting portion to the reference surface S so that the tooth tip side of the sharp-side processed tooth surface 4 is notched with a flat surface. It is possible to prevent an angular portion from being formed on the tooth surface 4. For this reason, such an angular portion can prevent the workpiece from being streaked at the chamfered sharp edge 14 of the helical gear 11, thereby achieving higher-quality chamfering. it can.

  In addition, since the tooth tip side of the acute-side machining tooth surface 4 has a convex curved surface and is retreated with respect to the reference surface S in this way, the retraction amount Q of the acute-angle side machining tooth surface 4 with respect to the reference surface S is obtained. As described above, since it can be gradually increased toward the tooth tip side, according to the present embodiment, the amount of chamfering by the acute angle side processing tooth surface 4 is increased toward the tooth tip side, that is, the workpiece is processed. If it goes to the tooth root side of the tooth 12 of the gear 11, it can be gradually reduced. For this reason, it becomes possible to prevent the generation | occurrence | production of the burr | flash on the tooth root side of the leaf 12 more reliably.

  Note that the retraction amount Q of the processed tooth 2 of the acute angle side processing tooth surface 4 is the chamfering width b of the acute side edge 14 of the tooth 12 of the helical gear 11 shown in FIG. The twist angle β is given by Q = b × tan β. In this embodiment, the retraction amount Q is (0.4 to 0.8) × b with respect to the chamfer width b of the acute angle side edge 14. The range. This is because if the retraction amount Q at the tooth tip is smaller than the above range, the acute-side machining tooth surface 4 on the tooth tip side is insufficiently relieved, and the workpiece is processed at the root side of the tooth 12 in the helical gear 11. This is because it may not be possible to reliably prevent the generation of burrs.

  On the other hand, if the retraction amount Q is larger than the above range, depending on the thickness of the processed tooth 2, the strength of the processed tooth 2 may be impaired on the tooth tip side, and chipping may occur during chamfering. Occurs. Therefore, it is desirable that the retraction amount Q at the tooth tip is set within the above range as in the present embodiment, for example, about 0.2 to 0.8 mm, and the tooth of the processed tooth 2 as described above. It is more desirable that the tooth tip side of the acute-angle side processed tooth surface 4 is retracted with respect to the reference surface S within a range not exceeding the center line R in the thickness direction.

DESCRIPTION OF SYMBOLS 1 Cutter body 2 Machining tooth 4 Acute angle side processing tooth surface 5 Obtuse angle side processing tooth surface 11 Machined helical gear 12 Machined helical gear 11 tooth 13 Tooth surface 14 Acute angle side edge 15 Obtuse angle side edge O Cutter Axis of main body 1 Axis of machined helical gear 11 S Reference surface P Pitch circle of processing tooth 2 Q Acute angle processing tooth surface 4 with respect to reference surface S Retraction amount in tooth thickness direction of tooth tip side b Acute angle side edge 14 chamfer width

Claims (4)

  The workpiece is a phrasing cutter that meshes with a helical gear and chamfers by pressing the edge of the tooth surface of the helical gear in the direction of the streak, and on the outer peripheral surface of the disc-shaped cutter body, The workpiece includes a gear-like machining tooth having an acute-angle machining tooth surface that presses an acute-angle side edge of a tooth of a helical gear and an obtuse-angle machining tooth surface that presses an obtuse-angle side edge. The flazing characterized in that the side processing tooth surface is retreated in the tooth thickness direction of the processing tooth with respect to a reference surface obtained by extending the acute side processing tooth surface on the tooth base side on the tooth tip side of the processing tooth. Cutter.   2. The phrasing cutter according to claim 1, wherein the acute-angle-side processed tooth surface is retracted from the reference surface on a tooth tip side with respect to a pitch circle of the processed teeth.   The phrasing cutter according to claim 1 or 2, wherein a tooth tip side of the acute angle side processing tooth surface is formed to have a convex curved surface and is retracted with respect to the reference surface.   At the tooth tip of the processed tooth, the retraction amount of the acute angle side processed tooth surface with respect to the reference surface is (0.4 to 0. 0.) with respect to the chamfer width b of the acute angle side edge of the tooth of the helical gear. 8) The phrasing cutter according to any one of claims 1 to 3, wherein x is in a range of xb.

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