JPS5994545A - Production of helical gear - Google Patents

Abstract

PURPOSE:To improve the accuracy in a tooth profile by rolling a blank material at the lap contact interval of an integer value and at the size larger than the prescribed face width then removing the end part thereof thereby decreasing the pulsation in the pushing and energizing force of a rolling tool on the blank material. CONSTITUTION:The working part 6a of a blank material 6 for a gear is rolled by allowing a larger size for the axial size b1 in said part than the intended size b3 of a tooth face. The fluctuation in the pushing and energizing force on the material 6 is decreased. The end part 7b of the generated gear is cut except a stem part 9a of the gear whereby a helical gear 9 having an intended face width b3 is formed. The fluctuation in the pushing and energizing force of the rolling tool on the blank material is thus decreased and the accuracy in the tooth profile is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing helical gears by rolling.

Conventionally, in order to roll gears, Figure 1 (a) + (b)
As shown, a pair of opposing gear tools (1), <
2) A gear blank (3) having a gear machined part (3a) having a width substantially equal to the tooth width shown in the design drawing is rotatably supported between the teeth, and the gear blank (3) is driven to rotate. Each of the gear tools (1) and ζ2) was pressed against a hydraulic machine, shoulders (4) and (5), or a cam to create a tooth profile number on the surface of the original gear material (3).

Therefore, each gear tool (1) in the rolling process.

(2) starts to contact the gear material (8), the teeth of each gear tool (1), (2) gradually bite into the surface of the gear material (3), and the teeth are subjected to a large compressive force. However, at this time, the gear tool (1
).

(2) The push-in force to be maintained is related to the volume of metal that the tool teeth can bite into and displace. ).

(2) - There will be a cyclic change that fluctuates for each tooth pitch. This variation mode is such that when the number of teeth of the gear to be rolled is even, the biting state of the gear tools (1) + (2) into the gear material (8) is symmetrical with respect to the center of the leaf material (8). Therefore, a pair of gear tools (1),,
(2), and when the number of teeth of the gear to be rolled is odd, vi, as shown in Fig. 3, both the left and right gear tools (1) and (Z) do not synchronize. Produces alternating pulsations.

In any case, the pulse 'tIJ phenomenon in this pushing effort adversely affects the rolling stroke of the gear tool as well as the tool axis, and deteriorates the accuracy of the manufactured gear.

In other words, as shown in Fig. 4, the expected correct tooth trace #
If the tooth trace curve m (B) is obtained for (A), instead of η・shi, there will be a depression (3b) on both sides of the tooth as shown in Figure 5.
+(3) The above-mentioned pulsation phenomenon that causes these problems, that is, the valley gear tool (1).

The variation in the pushing force against the gear material (d) in (2) is as follows:
As previously mentioned, by increasing the meshing ratio between the gear tools (1) + (2) and the temporarily rolled gear, and by keeping the length of the simultaneous contact line constant while they mesh. , can be reduced. In this respect, helical gears are said to be advantageous over spur gears because they can increase the meshing ratio and sometimes the overlapping meshing ratio. The length of the simultaneous contact line can also be determined by setting the type IId convergence ratio to an integer.
It can be kept constant.

To do this, as is clear from the formula below, the face width of the helical gear to be manufactured may be set to be an integral multiple of the axial pitch t (see FIG. 7).

b: Width of helical gear t: Axial pitch However, with conventional rolled helical gears, the tooth width is set as per the design drawing from the time of making the raw material, so there is overlapping meshing. The ratio is not necessarily an integer, and it has been difficult to stably obtain a high kgO wheel with a high tooth lead and tooth profile.

The present invention is based on the above-mentioned points, and provides a method for manufacturing helical gears with improved precision. The feature is that after creating a helical gear with a face width larger than , the ends of the helical gear are removed to create the required face width.

The invention will now be described with reference to illustrated embodiments.

In Figure 6, (6) is the gear surplus material, and the axial dimension b□ of the gear galley machining part (6a) is larger than the target face width dimension b2 or 'o3.

This gear material (6) is rolled in the same way as described above to create the helical gear (γ) shown in Figure 7, but the dimensions b□ above, that is, the helical gear (7). The face width is set to be an integral multiple of the four-direction pinch t of the helical gear (7). Therefore, the variation in the pushing effort of the gear tool (not shown) against the gear material (6) can be expressed as follows: It can be reduced more stably and effectively than before.And,
The end of the helical gear (7) created as described above (
7a) or both ends (7b) are removed leaving the gear shaft portion (8a) or (9a) shown in Figure 8 to create a helical gear with the desired face width (1:+2) or (b3). (8
) or form (9).

The above process! ,! According to the method of manufacturing a helical gear of the present invention, it is possible to obtain a stable and effective tendency to reduce the fluctuation of the pushing force, and to improve the tooth profile and tooth trace accuracy significantly compared to the conventional method. However, when forming the teeth 1 and b2 or b3, the incomplete tooth portions and pads at both ends caused by f and threading are removed at the same time, making it difficult to obtain a good finish. can be obtained.

Although the helical gear of the above-mentioned undercurrent force is applied to the helical gear manufacturing method of the present invention to a double push hydraulic rolling machine, the present invention is not limited to this, and for example, it can be applied to a segment die. It can also be applied when using a wheel-shaped tool with an internal surface or a rack-shaped tool.

As described above, according to the helical gear manufacturing method of the present invention, it is possible to stably and effectively reduce variations in the pushing effort of the rolling freight car tool into the gear material, so that the manufacturing method of the manufactured gear can be stably and effectively reduced. The tooth profile and tooth trace accuracy can be significantly improved.

[Brief explanation of drawings]

1(a) and 1(b) are a plan view and a front view showing a conventional gear manufacturing method by rolling, and FIG. 2 is a graph showing a pulsation phenomenon of tool pushing force in the manufacturing method shown in FIG. Figure 3 is an explanatory diagram showing the rolling state red when the number of teeth of the rolled gear is an odd number in the manufacturing method of Figure 1, and Figures 4 and 5 are tooth trace curves in the manufacturing method of Figure -A1. - Figures, figures showing tooth profiles, and Figures 6 to 8 are all explanatory diagrams showing the process of forming a helical gear by the manufacturing method of the present invention. (i), (2)... Gear tool (8r, (e)... Gear base material (4), (5) ・ ・ ・ γ field pressure planning 1 engine I (8) I ( 1)...Helical gear Fig. 1 (a) Fig. 2 Fig. 3 Fig. 4 Fig. 5 b

Claims (1)

[Claims] After rolling the gear material and making it into a helical gear with an integer meshing ratio and larger than the required face width, the ends are removed and the required A method for manufacturing helical gears characterized by finishing them with a face width of .