JP2005152940A - High-strength dedendum shape of rolling tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling tool which is high in the rigidity strength of a tooth and long in the breakage life. <P>SOLUTION: The rolling tool has, on the outer periphery, many teeth 8 on which a tapered tooth trace 15 is formed in the direction of the tooth trace, wherein the tooth depth h of a small end face 21 at the tip of the taper tooth trace 15 is made nearly equal to the tooth thickness w of a chamfer 16 at the inner end of the tapered tooth trace and the tooth depth h of the chamfer part 16 is made nearly equal to the tooth depth h' of the small end face. The ratio of the tooth thickness w of the chamfer 16 to the tooth depth h' of the small end face 21 is in the range of 1: 0.8-1.2 and the absolute value of an angle θ formed with a line 20 joining the tooth bottom of the chamfer 16 to the tooth bottom of the small end face 21 and the axial center 18 of the tool may be within 6°. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a large number of teeth with tapered teeth in the tooth trace direction on the outer periphery, rotates the teeth in mesh with the internal gear to be machined, and by the plurality of teeth with the tapered teeth. The present invention relates to a high-strength tooth root shape of a rolling tool in which a tapered tooth streak for preventing gear slippage during running is formed on the tooth surface of an internal spline of a power transmission device for an automobile.

In a conventional automobile manual transmission device, an external spline (external gear) and an internal spline (internal gear) have a tapered tooth trace to prevent gear slippage during travel. As shown, an internal spline 2 that is a workpiece is engaged with an external spline (external gear) (not shown) by a tooth line 12. The tooth trace 12 has a taper for preventing gear slippage during traveling. FIG. 6 is a cross-sectional view of the main part in a state where the chamfered portion of the rolling tool (only one tooth is shown) is pressed against the flank surface of the internal spline that is the workpiece and rolled. As shown in FIG. 6, this taper tooth line 12 is formed by cutting the biting portion 16 at the rear end of the taper tooth 15 of the rolling tool 1 with a flank surface 17 of the internal spline 2 (previously with a hob or pinion cutter) It was formed by grinding with a grindstone and partially forming it by rolling plastic working. A conventional outer spline type rolling tool according to Patent Document 1 is disclosed.
Utility Model Registration No. 2547999

  However, in order to taper the tooth trace 15 (FIG. 6) of a conventional rolling tool (the same applies to the rolling tool of Patent Document 1), it is cut in an oblique direction with respect to the rolling tool with a hob or pinion cutter, or FIG. As shown in Fig. 5, grinding was performed using a disk grindstone 9 in an oblique direction with respect to the rolling tool. For this reason, as shown in FIG. 8, the root diameter of the conventional rolling tool becomes smaller as it approaches the small end 21 at the tip of the tapered tooth 15 (broken line 6: BB cross section). It becomes higher and the strength of the teeth becomes weaker. The ratio of the tooth thickness w of the biting part (solid line 5) of the conventional rolling tool as shown in FIG. 8 to the tooth height h 'of the small end face was about 1: 1.3 to 1.9. Further, when grinding using a disc grindstone 9 that tapers the tooth trace 15 of a conventional rolling tool (the same applies to the rolling tool of Patent Document 1), the step 11 (solid line 5) is included in the tooth base shape of the rolling tool. As a result, the strength of the teeth is weakened. For this reason, there existed a subject that the breakage life of the conventional rolling tool became short.

  An object of the present invention is to provide a rolling tool having high tooth rigidity and a long breakage life.

  For this reason, the present invention provides a large number of teeth with tapered teeth in the direction of the tooth traces on the outer periphery, rotates the teeth meshed with the internal gear to be machined, and a plurality of teeth with the tapered teeth. In a rolling tool for rolling and plastically processing tapered tooth streaks for preventing gear slippage during running on the tooth surface of the internal spline of the automobile power transmission device, the tooth height of the small end surface of the tapered tooth trace By providing a rolling tool characterized in that the tooth thickness of the biting portion at the inner end of the tapered tooth trace is substantially the same, and the tooth height of the biting portion and the tooth height of the small end surface are substantially the same. Solved the above-mentioned problems of conventional products.

  In the rolling tool of the present invention, the tooth height h ′ of the small end face of the tapered tooth trace and the tooth thickness w of the biting part of the tapered tooth muscle inner end are substantially the same, and the tooth thickness w of the biting part of the conventional rolling tool is small. Compared with the ratio of the tooth height h ′ of the end face being about 1: 1.3 to 1.9, the tooth height h ′ of the small end face is greatly reduced, the tooth rigidity strength is increased, and the bite is bitten. By making the tooth height h of the portion substantially the same as the tooth height h ′ of the small end face, a portion having a weak tooth rigidity is eliminated as a whole, and a rolling tool having a long breakage life is provided.

Preferably, the ratio between the tooth thickness of the biting part and the tooth height of the small end face is in a range of 1: 0.8 to 1.2, and the tooth bottom of the biting part and the tooth bottom of the small end face are connected. The absolute value of the angle θ formed by the line and the tool axis may be within 6 °.
More preferably, the tooth base of the rolling tool is wire-cut to make the tooth base shape a smooth ellipsoidal surface that is continuous with adjacent flank surfaces, thereby significantly increasing the rigidity of the teeth and further improving the fracture life. It provided a long rolling tool.

  The tooth root shape of the rolling tool of the best mode for carrying out the present invention will be described with reference to FIGS. FIG. 1 is a partially enlarged outline view showing a tooth root shape of a rolling tool of the best mode for carrying out the present invention. A solid line 3 shows a contour line (cross section AA) of a biting section 7 and a broken line 4 shows FIG. 2A is a schematic overall perspective view of the rolling tool of FIG. 1, and FIG. 2B is a partial side sectional view of one tooth of the rolling tool of FIG. FIG. 3 is a schematic perspective view showing a main part of a method for forming the tooth base of the rolling tool of FIG. 1 by wire cutting with a wire.

  In the rolling tool of the best mode for carrying out the present invention, a large number of teeth 8 with tapered tooth traces 15 are provided on the outer periphery in the direction of the teeth, and as shown in FIG. A plurality of teeth 8 which are meshed with the gear 2 and rotated and provided with tapered tooth traces 15 are formed on the tooth surface of the internal spline 2 of the power transmission device for automobiles so as to prevent the gear from slipping out during traveling. In the rolling tool 1 for rolling and plastic working, the tooth height h of the small end face 21 at the tip of the tapered tooth 15 and the tooth thickness w of the biting portion 16 at the inner end of the taper tooth 14 are substantially the same, and the teeth of the biting portion 16 are the same. The rolling tool is characterized in that the length h and the tooth height h ′ of the small end face are substantially the same.

  1, preferably the ratio of the tooth thickness w of the biting portion to the tooth height h ′ of the small end face is in the range of 1: 0.8 to 1.2, and as shown in FIG. The absolute value of the angle θ formed by the line 20 connecting the tooth bottom and the tooth bottom of the small end surface and the tool axis 18 may be within 6 °. More preferably, as shown in FIG. 3, the tooth base of the rolling tool 1 is wire-cut using a wire 10 so that the tooth base shape is a smooth elliptical surface 19 continuous with adjacent flank surfaces. As a result, the rigidity of the teeth is remarkably increased and a rolling tool with a longer breakage life is provided.

Test rolling of the workpiece was performed using the rolling tool of the present invention shown in FIG. 1 and the conventional rolling tool shown in FIG. The workpiece specifications were: m2.1 × PA20D ° × Ng41, crushing amount: 0.45, and the number of rolling tool teeth: 25. The test results are shown in FIG. The broken line 6 (BB cross section) of the conventional rolling tool shown in FIG. 8 shows the tooth profile shape of the small end face 21, which was ground and finished with a hob. The ratio of the tooth height h ′ of the small end surface 21 and the tooth thickness w of the biting portion 16 is 1.8: 1, and the tooth profile of the small end surface 21 of the broken line 6 is compared with the cross section 5 (AA cross section) of the biting portion 16. The tooth height h ′ is high and the tooth strength is weak, and the angle θ between the line 20 connecting the root of the biting portion 16 and the bottom of the small end surface 21 and the tool axis 18 is 10 °. The tooth base of the biting portion 16 of the cross section 5 (AA cross section) has a step 11 due to the disk grindstone 9 (FIG. 7), and the strength of the teeth is weakened. For this reason, the damage life of the conventional rolling tool shown in FIG. On the other hand, in the rolling tool of the present invention shown in FIG. 1, the broken line 4 (BB cross section) shows the tooth profile shape of the small end cross section 14, and the tooth root shape is formed by wire cutting with the wire 10 shown in FIG. There is no step, and it has a smooth shape with a large oval shape 19. The tooth height h of the small end surface 21 and the tooth thickness w of the biting portion 16 are substantially the same, and the ratio of the tooth height h of the biting portion 16 and the tooth height h 'of the small end surface is substantially the same, so that the overall high rigidity tooth profile. It has a shape. The failure life of the rolling tool of the present invention shown in FIG. 1 is more than 4000 processed workpieces, which is more than 8 times that of the conventional rolling tool shown in FIG.
[Effect of Best Embodiment of the Present Invention]

  In the rolling tool of the present invention, the tooth height h ′ of the small end face of the tip of the tapered tooth muscle is substantially the same as the tooth thickness w of the biting portion of the inner end of the tapered tooth muscle, and the tooth thickness w and tip of the biting portion of the conventional rolling tool are the same. Compared with the ratio of the tooth height h ′ of the small end face being about 1: 1.3 to 1.9, the tooth height h ′ of the small end face is greatly reduced, the rigidity of the tooth is increased, and By making the tooth height h of the biting portion substantially the same as the tooth height h ′ of the small end face, a portion having a weak tooth rigidity is eliminated as a whole, and a rolling tool having a long breakage life is provided.

Preferably, the ratio between the tooth thickness of the biting part and the tooth height of the small end face is in a range of 1: 0.8 to 1.2, and the tooth bottom of the biting part and the tooth bottom of the small end face are connected. The absolute value of the angle θ formed by the line and the tool axis may be within 6 °.
More preferably, the tooth base of the rolling tool is wire-cut to make the tooth base shape a smooth ellipsoidal surface that is continuous with adjacent flank surfaces, thereby significantly increasing the rigidity of the teeth and further improving the fracture life. It provided a long rolling tool.

It is a partial expanded outline figure which shows the tooth root shape of the rolling tool of the best form for implementing this invention. (A) is a schematic whole perspective view of the rolling tool of FIG. 1, (b) is a partial side sectional view of one tooth of the rolling tool of (a). It is a schematic principal part perspective view which shows the method of forming the tooth base of the rolling tool of FIG. 1 by a wire cut process with a wire. The graph which shows the test rolling result of a workpiece using the rolling tool of this invention shown in FIG. 1 and the conventional product rolling tool shown in FIG. The principal part perspective view of the internal-tooth spline which is a workpiece. The principal part sectional drawing of the state which presses the taper tooth trace of a rolling tool (only 1 tooth | gear is shown) to the flank surface of the internal-tooth spline which is a workpiece, and performs rolling plastic processing is shown. The principal part perspective view which grinds the conventional rolling tool using a disk grindstone. It is a partial expanded outline figure which shows the conventional product rolling tool tooth root shape.

Explanation of symbols

1: Rolling tool 8: Teeth 10: Wire cut wire 15: Taper tooth 16: Biting portion 21: Small end surface h: Teeth height h 'of biting portion 16: Teeth height of small end surface 21 θ: Teeth of biting portion Angle w between the line connecting the bottom and the tooth bottom of the small end surface and the tool axis: tooth thickness of the biting portion

Claims (3)

  A large number of teeth with tapered teeth are provided on the outer periphery, and the teeth are meshed with the internal gear to be machined and rotated. In a rolling tool for rolling and plastically processing tapered tooth streaks for preventing gear slippage during running on the tooth surfaces of the internal splines of the apparatus, the height of the small end surface of the tapered tooth trace and the inner end of the tapered tooth trace A rolling tool characterized in that the tooth thickness of the biting part is substantially the same, and the tooth height of the biting part and the tooth height of the small end face are substantially the same.   The ratio between the tooth thickness of the biting part and the tooth height of the small end surface is in the range of 1: 0.8 to 1.2, and the line connecting the tooth bottom of the biting part and the tooth bottom of the small end surface and the tool The rolling tool according to claim 1, wherein an absolute value of an angle θ formed with the axis is within 6 °.   The rolling tool according to claim 1 or 2, wherein the tooth base of the rolling tool is formed into a smooth ellipsoidal surface that is continuous with flank surfaces adjacent to each other by wire cutting.

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