JPS621489Y2 - - Google Patents

Description

[Detailed Description of the Invention] The invention of this application relates to a gear having a modified tooth profile. Specifically, the purpose is to provide a gear having a tooth profile that ensures ideal meshing by using a theoretical tooth profile as an actual tooth profile.

Conventionally, the tooth profile of a gear such as a curved plate in a planetary gear reducer is usually modified from a theoretical curve in order to ensure back clearance.

FIG. 1 shows the tooth profile of a curved plate in a conventional planetary gear reducer, where 1 is the curved plate and the outermost dotted line 2 is the theoretical trochoid tooth profile of the curved plate 1. 3 is an outer pin with which the tooth profile of the curved plate 1 is engaged. The actual tooth profile of the curved plate 1 is 2' shown by a solid line, and a trochoid envelope tooth profile is used, which is cut parallel to the theoretical curve 2 by a distance δ inward in the normal direction. It is secured.

However, as is clear from FIG. 1, with this method, the tooth profile is not a theoretical tooth profile, so the outer pin 3 and the tooth profile 2' do not mesh theoretically (completely mesh). the result,
Irregular occlusion was inevitable.

The present invention was developed to solve these drawbacks of conventional tooth profile modification, and it achieves a backlash by rotating the theoretical curve by a phase angle △. (See Figure 2).

In the figure, the dotted line 2 is a trochoid theoretical curve that forms the tooth profile of the curved plate 1 (the trough of the tooth profile in the figure). Then, a curve 2' obtained by rotationally displacing this theoretical curve 2 to the left by △ψ around the center O of the curve plate
If the valley of the tooth profile is formed by the downward surface formed by the curve 2'' obtained by rotationally displacing the theoretical curve 2 by △ψ to the right of the curved plate center O, the valley of the tooth profile is formed by the curve 2'.
and 2'' intersect at an acute angle at the peak and valley of the tooth profile.In this case, naturally, the two curves 2' and 2'' are trochoid theory curves.
The intersections of these peaks and valleys make little contribution to load transmission, so the intersections of the two curves 2' and 2'' should be smoothly continuous as shown by the dotted lines in the figure, and used with appropriate escape. Regarding the escape structure of this part, please refer to the utility model registration application (Japanese Utility Model Publication No. 57-23455) filed on the same day as the present application.

Then, the part excluding the relief part, that is, the second
Since the downward and upward surfaces A in the figure are all constructed from trochoidal theoretical curves, complete theoretical engagement is achieved.

Figures 3 and 4 compare the conventional tooth profile modification method for a curved plate and the modification method of the present invention, and show the relationship between the outer pin 3 that engages with the curved plate 1 and the curved plate when the curved plate 1 is rotated. This shows the relative motion of .

In Figure 3, since the outer pin 3 does not approach from the tangential direction at the starting point of engagement of the curved plate, it collides with the curved plate, resulting in non-theoretical engagement in a small range B (theoretically, one tooth engagement). After that, it leaves again in a non-tangential direction.

On the other hand, in Fig. 4, the outer pin 3 approaches the starting point of engagement with the curved plate 1 from the tangential direction, and after theoretically engaging in a wide range C, it leaves again in the tangential direction at the engagement end point. ideal. Incidentally, it goes without saying that the theoretical meshing range C can be determined to be Δ to the optimum condition.

As you can easily understand from the above explanation, the present invention maintains the trochoid theoretical curve and performs backlash correction, so the meshing is done in an extremely theoretical manner, and uneven rotation, vibration, noise, etc. are greatly reduced. It was done.

In addition, by maintaining the trochoid theoretical tooth profile, theoretical engagement occurs over a wide range, increasing the engagement ratio (increasing the number of simultaneous engagements) and reducing the surface pressure on the engagement surfaces, which significantly improves the limit of damage such as pitting. do.

The present invention has been described above using the curved plate of a planetary gear reducer as an example, but it can also be applied to pumps and motors using cycloidal gears or trochoidal tooth profiles.

[Brief explanation of the drawing]

FIG. 1 shows a known tooth profile modification method for a curved plate. FIG. 2 shows the novel tooth profile modification method of the present invention. FIG. 3 shows the meshing state of the curved plate and the outer pin in a known planetary gear reducer. FIG. 4 shows the state of engagement between the curved plate and the outer pin in the present invention. In the figure: -1...Curved plate, 2...Theoretical trochoid curve (of the tooth profile), 2', 2''...Theoretical tooth profile after modification, 3...Outer pin, A...(The meshing of the modified tooth profile is ) down side and up side, B...
Meshing range (of known tooth profile), C...theoretical meshing range (of the present invention).

Claims (1)

[Scope of utility model registration request] It has a tooth profile formed by a descending surface and an ascending surface, and the descending surface of the tooth profile consists of a curve 2' obtained by rotationally displacing one trochoid theoretical curve 2 to the left around the center 0 of the gear. , and a trochoidal tooth profile gear characterized in that the upward surface of the tooth profile is formed by a curve 2'' obtained by rotationally displacing the trochoid theoretical curve 2 by Δψ to the right around the center 0 of the gear.