JPS621488Y2 - - 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.

Now, in order to solve the drawbacks of the conventional tooth profile modification, the inventor of the present invention has solved the problem by rotating the theoretical curve by a phase angle △ with respect to the gear center.
We devised a method of taking a backlash and filed the application at the same time as the present application. The outline will be explained below (see Fig. 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, the theoretical curve 2 is rotationally displaced △ψ to the left around the curved plate center O, and the downward surface formed by the curve 2' and the theoretical curve 2 are set to the right △ of the curved plate center O.
When the trough of the tooth profile is formed by the upward surface formed by the curve 2'' obtained by rotational displacement by ψ, the curves 2' and 2'' intersect at an acute angle at the peak and trough of the tooth profile. In this case, as a matter of course, the two curves 2' and 2'' are trochoid theoretical curves.The areas where these peaks and valleys intersect are areas that hardly contribute to load transmission. However, if you leave it as is, due to its processing accuracy and elastic deformation,
This may cause abnormal meshing with the mating tooth profile (outer pin). Also, in tooth profile grinding using the shaping method, it is difficult to provide a grinding wheel with a sharp point.

The present invention relates to a tip relief structure at the peaks and valleys of a corrected trochoid theory tooth profile having such problems, and several embodiments thereof will be described in detail below.

FIGS. 3 to 5 are examples of valley relief structures.

Now, in the embodiment shown in FIG. 3, the peaks B formed at the valleys of the trochoid theory correction curves 2' and 2'' are tangentially continued by a straight line and a circular arc.

In FIG. 4, the apex B of the trough is also shown with only a circular arc.

In FIG. 5, two circular arcs with different curves are connected.

FIGS. 6 to 9 show examples of relief structures for the peaks.

Now, in FIG. 6, the peaks C formed at the peaks of the trochoid theoretical curves 2' and 2'' are connected only by circular arcs.

FIG. 7 shows the trochoid theoretical curves 2' and 2'' connected by two circular arcs and a straight line.

In FIG. 8, trochoid theoretical curves 2' and 2'' are connected by two straight lines and a circular arc.

In FIG. 9, trochoid theoretical curves 2' and 2'' are connected by two circular arcs with different radii.

The above has shown some combinations of circular arcs and straight lines in the relief structure of peaks and valleys, but of course other combinations are possible. Which of these is chosen is determined by the trochoid theoretical range of the tooth profile (A in Figure 2) and the amount (size) of bumps in the normal direction of the valleys and peaks. .

The present invention is constructed as described above, and since no cusp appears on the tooth profile curve, cutting and grinding of the tooth surface is easy.

Also, by escaping the apex in this way, there is an effect that the backlash in the normal direction can be freely taken. As a result, it is possible to improve the machining accuracy of gears with modified tooth profiles and to prevent abnormal meshing due to elastic deformation.
This greatly contributes to improving the efficiency and extending the life of gear transmission devices.

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

[Brief explanation of the drawing]

FIG. 1 shows an example of tooth profile modification in a known gear. FIG. 2 shows the structure of the new modified tooth profile. FIGS. 3 to 5 show examples of relief structures for the peaks in the valleys of the modified tooth profile according to the present invention. Figure 6~
FIG. 9 shows an embodiment of the relief structure of the peak of the modified tooth profile according to the present invention. In the figure; 1... curved plate, 2... (tooth profile)
Trochoid theoretical curve, 2', 2''...Theoretical trochoid tooth profile after modification, A...Downward and upward surfaces (on which theoretical meshing of the modified tooth profile is performed), B...Apex of valley, C...Mountain The apex of the part.

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 the upward surface of the tooth profile is formed by a curve 2'' obtained by rotationally displacing the trochoid theoretical curve 2 by △ψ to the right around the center 0 of the gear, and the tooth profile where the curves 2' and 2'' intersect is A trochoidal tooth gear characterized by having peaks formed in the peaks and valleys shaved off in a continuous curve.