JPS6116439Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is based on a trochoidal planetary gear mechanism, such as a cyclo reducer (registered trademark), in which a trochoidal tooth profile (epitrochoid parallel curve) is used as an external gear, and a circular arc tooth profile made of a pin is used as an internal gear. This is related to improvements.

Figure 1 shows a planetary gear reducer according to the present invention,
1 is an input shaft, 2 is an output shaft, and these are on a common center line. The input shaft 1 is received by a rolling bearing 4 on a casing 3 and a rolling bearing 6 on a carrier 5 integrated with the output shaft 2, and is supported by an output shaft 7. The casing 3 is composed of an end cover portion 3a on the input shaft 1 side, an end cover portion 3b on the output shaft 2 side, and an annular frame 3c therebetween. This annular frame 3
At c, an outer roller 8a is supported and held in a predetermined position by the teeth of an internal gear.

A pair of eccentric cams 9 and 10 are mounted on the input shaft 1 with a phase difference of 180 degrees, and external gears 11 and 12 having circular arc tooth shapes are attached to these eccentric cams 9 and 10. are fitted through bearings 13 and 14. Holes 16 and 17 having a diameter twice the sum of the diameter of the carrier pin 15 (bush 18) and the amount of eccentricity of the eccentric cams 9 and 10 are bored at predetermined positions in the external gears 11 and 12. , the hole 16,1
7 is planted in carrier 5 and bush 1
A series of carrier pins 15 fitted with 8 are inserted. Therefore, when the input shaft 1 is driven, the external gears 11 and 12 are eccentrically rotated by the eccentric cams 9 and 10 as the input shaft 1 rotates, but the orbital motion is absorbed by the holes 16 and 17. External gear 1
Only the rotations of rotations 1 and 12 are extracted as rotations of the output shaft 2 via the carrier pin 15.

In such a planetary gear reducer, the circular arc tooth profile of the internal gear is made up of a combination of an outer pin 8 and an outer roller 8a, and the outer pin 8 is attached to the frame 3c as a housing as shown in FIG. A frame supported at two points and an outer roller 8a as shown in FIGS.
It is already known that the frame is divided into two parts and the outer pin 8 is supported at three points.

However, since the distance between the supporting points of the two-point support becomes long, the rigidity is small and the structure is easily bent, resulting in problems such as uneven contact. In addition, the three-point support frame shown in FIG. 4 increases the rigidity against the load acting between the external gear 11 and the outer roller 8a, and reduces the deflection of the outer pin 8, that is, the bending stress of the outer pin 8. Although this increases the load capacity of the reducer, this three-point support system is
Whereas the frame with the structure shown in Figure 3 required holes to be drilled in two places for one outer pin, it was necessary for three holes to match exactly, which caused problems in maintaining accuracy. .

As shown in FIG. 6, the present invention is a two-way roller 8a.
The frame is divided into two parts, and an intermediate support portion 20 having a minute gap δ between the outer pin 8 and the intermediate portion of the frame for allowing bending that will not cause any actual harm is provided, making the processing easier.

Now, the deflection of the pin 8 caused by the load acting between the outer roller 8a and the external gear 11 varies depending on the size of the reducer, the reduction ratio, and the selection of various dimensions of the gear. In the case of frame 3c in Fig. 3, the surface pressure generated between the external gear 11 and the pin 8 may reach several tens of microns under a load with sufficient margin. Although such deflection has the effect of absorbing gear machining errors under light loads, it generally becomes detrimental as the load increases.

In the present invention, deflection that does not cause actual damage is allowed, but when the load exceeds a certain level, the amount of deflection of the outer pin 8 increases, and the gap δ between the frame 3c and the intermediate support portion 20 increases.
, the outer pin 8 contacts the intermediate support portion 20. Then, it will be supported at three points including both ends which were supporting parts until then. Therefore, the span of the outer pin as a beam receiving the outer pin load becomes small, and the bending moment, that is, the amount of deflection and bending stress acting on the outer pin 8 becomes small.

By providing the intermediate support portion as described above, 1. When the load on the reducer exceeds a certain level, the outer pin 8 becomes supported at three points, increasing the rigidity of the internal gear. Therefore, problems such as uneven contact with the external gear due to bending of the outer pin 8 and limitation of load capacity of the reducer due to bending stress of the outer pin are solved.

2. Holes for one outer pin only need to be formed in two places, and can be manufactured at a lower cost than the known three-point outer pin support frame.

[Brief explanation of the drawing]

FIG. 1 shows a planetary gear reducer (partially cut away), FIG. 2 shows an enlarged sectional view of FIG. 1, and FIGS. 3 to 5 show a known outer pin support structure. FIG. 5 is a cross-sectional view taken from FIG. 4, and FIG. 6 shows a support structure according to the present invention. FIG. 7 is a cross-sectional view of FIG. 6. In the diagram: - 1...Input shaft, 2...Output shaft, 3...Casing, 3a...(input shaft side)
End cover part, 3b... (output shaft side) end cover part, 3c...
...Annular frame, 4...Bearing, 5...Carrier, 6,7
...Bearing, 8...Outer pin, 8a...Outer roller,
9, 10... Eccentric cam, 11, 12... External gear, 13, 14... Bearing, 15... Carrier pin, 16, 17... Hole, 18... Bush, 1
9, 19'... Support groove, 20... Intermediate support portion.

Claims (1)

[Scope of utility model registration request] An outer roller 8 divided into two parts is attached to an outer pin 8 attached to the inner surface of an annular frame 3c which is the housing of the internal gear.
a is rotatably mounted, and an intermediate support portion 2 of the outer pin 8 is provided with a minute gap δ between the outer rollers 8a, 8a.
An internal planetary gear reducer characterized in that an internal gear has a circular arc tooth profile formed by a pin and a roller, and an external gear has a trochoidal tooth profile.