JPS6250690B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a multi-stage planetary gear system.

A planetary gear device consists of a sun gear, a plurality of planet gears that mesh with the sun gear, and a carrier that supports the planet gear, and the most important thing is the support of the sun gear and the carrier at the center. That is, the seventh
As shown in the figure, when the center of the carrier 3 shifts upward, the meshing part a of the planetary gear 1A with the internal gear 4,
Meshing portion b of planetary gears 1B and 1C with sun gear 2,
At c, there is no backlash and there is overmeshing, and conversely, at the meshing part d of the planetary gear 1A with the sun gear 2, and the meshing parts e and f of the planetary gears 1B and 1C with the internal gear 4, the backlash is large and there is a lot of play. It is a loose mesh, and in any case, effective power transmission and speed conversion effects cannot be expected. Furthermore, as shown in FIG. 8, even when the center of the sun gear 2 is misaligned, there is almost no buckling at the meshing part g with the planetary gear 1A, and there is a large buckling at the meshing parts h and i with the planetary gears 1B and 1C. So, as in the case of Figure 7,
Highly efficient power transmission cannot be expected. Furthermore, if the shaft support error of multiple freewheeling gears to the carrier is large, and as shown in FIG. 9, the pitch between the planetary gear 1A and the center is long, and the pitch between the planetary gear 1B and the center is short, as shown in FIG. Overmeshing j similar to Fig. 8,
k, loose meshing l, m, and proper and good meshing cannot be obtained.

As described above, deviations from the center of the sun gear and carrier, errors in the shaft support position of the planetary gear to the carrier, etc. are the most important problems in this type of planetary gear device. uses a fairly complex and sophisticated mechanism,
Gears have also been processed with extremely high precision, but in any case, it was unavoidable that this would result in a cost disadvantage.

This invention eliminates the conventional mechanism configuration that actively supports and fixes the sun gear and carrier, and automatically sets the center of rotation of the sun gear and carrier at the center position determined by the relative positional relationship of the internal gear and the planetary gear. The present invention is applied to the concept of self-alignment, and will be specifically explained below with reference to the drawings.

FIG. 1 shows one embodiment of the present invention, and FIG. 2 is a sectional view of the main parts. As is clear from FIG. 1, this embodiment is a four-stage planetary gear reduction device, in which power is transmitted from the first stage sun gear 6a of the input shaft 5 to the output shaft 9 of the fourth stage final stage carrier 8d. The drive torque of the output shaft 9 is increased and the rotation speed is decreased.
That is, the power of the input shaft 5 is transmitted to the first stage sun gear 6a.
The information is sequentially transmitted to the first stage planetary gear 7a, the first stage carrier 8a, the second stage planetary gear 7b, the second stage carrier 8b, the third stage planetary gear 7c, the third stage carrier 8c, and the fourth stage planetary gear 7d of the final stage, and then to the final stage gear 7d. 8
It can be taken out from the output shaft 9 via d. Note that the internal gear 10 is fixed.

As shown in the drawings, this invention does not have any mechanism structure to support the sun gear and carrier of each stage, and therefore is free in all directions, front, back, left, and right, and the planetary gear, internal gear, and other structures are free. Automatically centered to a stable position determined by the component. In addition, a ball 11 is inserted as a self-aligning component between the carrier of each stage and the sun gear, but this is to maintain appropriate clearance in each stage of the planetary gear mechanism, for example, the second stage. The ball 11b provides an appropriate clearance between the second stage carrier 7b and the second stage sun gear 8b to avoid accidents such as contact. The cross-sectional view in FIG. 2 clarifies the relationship between the planetary gear, the carrier, and the sun gear shaft. Power is transmitted to the next stage planetary gear (not shown) through the gear. A grease chamber 12a is provided at the fitting part of the planetary gear shaft 12 with the planetary gear 7, and after the planetary gear 7 is fitted, a retaining pin 14 is press-fitted to remove the planetary gear 7 from the shaft 12. prevent. The carrier 8 and the planetary gear 12 may be coupled by various methods such as electron beam welding, shrink fitting, press fitting, etc.
In addition, a perspective view is shown in FIG. In addition, each ball for forming a clearance between the sun gear and carrier in each stage, or between the planetary gear of the current stage and the previous stage carrier, is placed either on the sun gear side or the carrier side, as shown in Figures 4 and 5. It may be supported by

This invention is configured as described above. Next, its action and effect will be explained based on FIGS. 6 and 10. Figure 6 shows a case where the meshing state of the sun gear 2, three planetary gears 1A, 1B, 1C, and internal gear 4 is ideal, and the backlash of each gear is appropriate, and of course the three planetary gears 1A, 1
B and 1C share the load equally. By the way, in a planetary gear system, it is extremely difficult to achieve the above-mentioned state of complete meshing, and as explained earlier,
The troubles illustrated in FIGS. 6, 7, and 8 often occurred. However, the self-aligning concept of this invention, which does not support or fix the carrier or sun gear, eliminates the possibility of the above-mentioned troubles occurring.

That is, in FIG. 10, the planetary gears 1A and 1B indicated by broken lines are the same as the problem shown in FIG. It will automatically move to point β, which has been rotated by a slight angle.

That is, the planetary gears 1A and 1B indicated by broken lines are overmeshing j of the planetary gear 1A with the internal gear 4, loose meshing l with the sun gear 2, and loose meshing m of the planetary gear 1B with the internal gear 4, Overmeshing with internal gear 2,
In order to improve this, the carrier center is moved to the position shown by the solid line, and this means rotating the carrier center from the above α to β. In other words, it involves automatically correcting the center position of the carrier that supports the planetary gears or the center position of the sun gear that meshes with each planetary gear so that the loads on each planetary gear are balanced, and in the above case. , the most balanced and stable meshing state for the loads of the planetary gears is the position indicated by the solid line where the center of the carrier moves to point β.

In this way, the present invention, which self-aligns the sun gear and carrier, causes each planetary gear to share the load as balanced as possible; death,
It has advantages such as reduction of gear diameter, reduction of unreasonable unbalanced loads such as rotary distortion, c) Gear errors can be absorbed, and gear machining accuracy and deviation of deviation amount do not require as much precision as shown on the left. The elimination of gear and carrier supports reduces the number of frictional parts, reduces friction loss, improves the efficiency of the entire device, and simplifies the overall configuration of the device.

The fields of application of the present invention include various speed increasers, speed reducers, motors and gear motors combined with various actuators.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the embodiment, Fig. 2 is a sectional view of the main part, Fig. 3 is a perspective view thereof, Figs. 4 and 5 are views showing other insertion examples of the clearance forming ball, and Fig. 6 is a sectional view of the embodiment. Figure 7 shows the ideal case of each gear mesh.
8 and 9 are diagrams illustrating problems in conventional gear meshing, and FIG. 10 is a diagram illustrating a corrected state of each gear meshing according to the present invention. 5...Input shaft, 6a...First stage sun gear, 7a...
...First stage planetary gear, 8a...First stage carrier, 11
a... First cardboard for clearance formation, 6b...
Next stage sun gear, 7b...Next stage planetary gear, 8b...
Next stage carrier, 11b... Next corrugated board for clearance formation, 9... Output shaft, 10... Internal gear,
8d...Final stage carrier.

Claims (1)

[Claims] 1. A sun gear on an input shaft, a plurality of first-stage planetary gears that mesh with the sun gear, a first-stage carrier that supports these planetary gears, and a first-stage corrugated ball for forming a clearance interposed in the center of each of the sun gear and first-stage carrier. , a next-stage sun gear integrally formed with the first-stage carrier, a plurality of next-stage planetary gears that mesh with the next-stage sun gear, a next-stage carrier that supports these next-stage planetary gears, and a next-stage corrugated ball for forming a clearance. etc., multi-stage sun gear, planetary gear,
A multi-stage planetary gear device comprising a carrier, a clearance-forming ball, an internal gear integrally meshing with the multi-stage planetary gears, and an output shaft formed at the final stage of the carrier.