JPS604391B2 - Trochoid tooth gear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a trochoidal tooth gear used as a planetary gear of a cyclo reducer (registered trademark).

The theoretical tooth profile of a conventional trochoidal tooth profile gear is an envelope of a trochoid curve, and this can be easily derived by using a circular arc tooth profile as a mating tooth profile and using perfect mesh theory.

A trochoidal curve 1 as shown in FIG. 1 is a locus drawn by a point 4 within the radius of the rolling circle when the rolling circle 3 rolls completely over the base circle 2.

The conventional tooth profile curve is arranged so that each point on the trochoid curve 1 is equidistant h to the extent that interference does not occur inside the normal direction of each point.
The tooth profile curve 5 was moved by o, and theoretically all the teeth would mesh.

When creating this moving tooth profile curve 5, the moving distance ho is set within a range where the moving tooth profile curve 5 does not cause interference.
I had decided. In the conventional movable tooth profile curve 5 created in this way, there is no interference part, and due to tooth profile correction, elastic deformation, etc., as shown in FIG. The gear engaged with the pin 6.

Therefore, in the meshing in this part, since both the movable tooth profile curve 5 and the outer pin 6 are convex parts, the surface pressure is high, and the sliding speed is also higher than in the trough part, so the wear loss is large, and the material is not sufficient. strength is required. Furthermore, it was also a cause of noise generation, which was said to be caused by slipping. In addition, this tooth profile curve generally shows that the higher the reduction ratio, the smaller the diameter of the pin gear pin (including the case of the outer roller). There were also limits.

For this reason, when a gear using a tooth profile curve with no interference part in the theoretical curve is used in a cyclo reducer (registered trademark), etc., 1
The maximum reduction ratio that can be achieved in a stage is 1 to 8 workmanship, which is the design and manufacturing limit, and if the reduction ratio is 1/5 or more, the tooth profile of the mating pin gear will also have a diameter of 4. Since rollers cannot be used, the pin has no rollers, resulting in a decrease in efficiency due to friction loss compared to when rollers are used. An object of the present invention is to improve the above-mentioned drawbacks and provide a trochoidal tooth gear that can achieve a high reduction ratio without reducing the tooth profile diameter of the mating pin gear. below,
To explain it with a diagram, each point on the trochoid curve 1 that does not cause interference in FIG. h or h2 to create trochoid movement curves 7 and 8.

These movement curves 7 and 8 have interference parts 9 and 10
It is. The present invention provides the above-mentioned trochoid movement curves 7 and 8.
The remaining trochoid movement curve shown by the thick line in the diagram after removing the interference parts 9 and 10 from the diagram is taken as the theoretical tooth profile curve,
Its enlarged view is shown in FIGS. 3a and b'.

Hereinafter, a case of a cyclo reducer (registered trademark) in which a trochoidal tooth gear according to the present invention is internally engaged with a fixed pin will be described.

In FIGS. 4 and 5, the center 0 of the gear 11 is eccentric by e compared to the center 02 of the arrangement frame of the outer roller 12, which is the tooth of the mating pin gear.

Now, if the gear 11 rotates eccentrically around the center 02, the troughs 13 of the gear 11 will sequentially come into contact with the outer roller 12,
The gear 11 rotates. In this case, the ratio of the eccentric rotation speed around the center 02 to the rotation speed of the gear becomes the gear ratio. When the contact of the gear 11 of the present invention with the outer roller is explained as a relative contact operation in which the pin of the pin gear moves and meshes with the trochoidal tooth gear 11, the outer circumferential circle 14 of the outer roller as shown in FIG. It transfers while touching the curve 7 or 8, and while the center of the outer roller 12 moves from P, to P2 in the figure, the contact point is K, →Kh→
The outer roller 12 moves in the order of C→B→A→K2, and the movement of the outer roller 12 largely detours around the peak of the gear and approaches the valley 13 from a direction almost perpendicular to it, and after engaging in a very short time, the outer roller 12 moves again. They are separated vertically. Since the gear curve of the trochoidal tooth profile gear of the present invention is configured as described above, the meshing of the pin gear with the pin is a meshing between a circle and the trochoidal curve according to the gear meshing theory, so that accurate meshing transmission is possible. It is possible, and if the number of teeth is increased in order to increase the reduction ratio with the same diameter in a conventional trochoid tooth gear that does not cause interference, is it possible to reduce the diameter of the adjacent outer pin (or roller)? , it is necessary to reduce the height of the tooth height that contributes to torque transmission, or to use both together, but as the reduction ratio increases, the torque increases accordingly, so in either case, In practice, it was impossible to increase the number of teeth with the same diameter due to insufficient strength, but by using the trochoid tooth profile gear of the present invention, even if the number of teeth is increased with the same diameter, it is not possible to increase the number of teeth with the same diameter. (outer pin or roller) can be made large, so
A gear with a large reduction ratio can be obtained with the same diameter.

In addition, since the diameter of the circle as the mating tooth can be made large, it is possible to use a roller frame as the mating tooth.
It becomes possible to provide a gear reducer that is small and has a large reduction ratio.

Furthermore, the meshing (contact) between the outer roller (outer pin) and the gear is a convex and concave contact, which reduces Hertzian surface pressure, improves the pitching limit, and improves the meshing between the gear and the outer pin (roller). Since the tooth tips are closer to the troughs and do not come into contact with each other at the tooth tips where the sliding speed is high, wear is reduced, life is extended, and noise caused by slipping can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the advantages of the conventional tooth profile curve and the tooth profile curve of the present invention, and FIG. 2 is a diagram illustrating the contact between the conventional gear and the outer pin. 3a is an enlarged view of curve 7 in FIG. 1, and b is an enlarged view of curve 7 in FIG.
FIG. 8 is an enlarged view of curve 8 in the figure. Further, FIG. 4 is a schematic diagram illustrating the operation when the gear of the present invention is used in a planetary gear reducer, and FIG. 5 is a state diagram illustrating the contact between the outer roller and the tooth profile. Explanation of symbols: 1... Trochoid curve, 7, 8... Curve, 9, 10... Interference part. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. In an internally meshing gear device with a pin gear and a trochoid tooth gear, each point on the trochoid curve that does not cause interference is moved inward in the normal direction of each point by an equal distance greater than the length that causes interference. A trochoid tooth profile gear whose theoretical tooth profile curve is the remaining trochoid shift curve after removing the interference part of the trochoid shift curve.