JPH10299841A - Inscribed meshing epicyclic gear structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a inscribed meshing epicyclic gear structure (sorting type) low in noise with no increase in production costs. SOLUTION: Power transmission between an input shaft 110 and a sorting shaft 140 in a first stage reduction mechanism S101 of a sorting type inscribed meshing epicyclic gear structure, is carried out by means of friction drive between a sun roller 120 each epicyclic roller 130, which are assembled in the respective shafts 110 and 140 by means of spline connection. Pressurizing force between both the rollers 120 and 130 is given by assembling a presurizing ring 137 around the respective epicyclic rollers 130.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a speed reducer or a speed-increasing gear, particularly to a speed reducer or a speed-increasing gear which is required to be small in size and to have high output and extremely low noise. The present invention relates to an internal meshing planetary gear structure suitable for the present invention.

[0002]

2. Description of the Related Art Conventionally, an internally meshing planetary gear structure of a type in which the rotation of an input shaft (first shaft) is divided and divided into the rotations of a plurality of distribution shafts and then reduced in speed is disclosed in, for example, JP-A-60-26.
0737, JP-A-5-44789 and JP-A-5-44789.
No. 340450, or US Pat.
No. 1 and British Patent No. 927648.

FIGS. 4 to 6 show an example of an internally meshing planetary gear structure disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 5-44789.

When the input shaft (first shaft) 10 rotates, the gears 20 and 3 of the first-stage reduction mechanism S1 correspond to the rotation.
0 (31, 32, 33), the second-stage speed reduction mechanism S2
The three sorting shafts 40 (41, 42, 43) rotate at the same speed in the same direction (the direction opposite to the input shaft 10). Each of the three sorting shafts 40 has two eccentric bodies 50 arranged in the axial direction, a total of six eccentric bodies 50 (51a, 51
b, 52a, 52b, 53a, 53b) are fitted.

When the eccentric body 50 rotates at the same speed in the same direction with the rotation of the distribution shaft 40, the two external gears 60 (60a, 60b) fitted to the eccentric body 50 On the other hand, they rotate eccentrically. The two external gears 60 have their maximum eccentric directions deviated from each other by 180 °, and are inscribed in an internal gear 70 concentric with the input shaft 10, respectively.

In this example, the number of teeth of the external gear 60 is 58,
Since the number of teeth of the internal gear 70 is set to 60, the difference in the number of teeth is two. Therefore, each time the distribution shaft 40 (or the eccentric body 50 incorporated therein) makes one rotation, the external gear 60 rotates eccentrically only once with respect to the input shaft 10, and as a result, the internal teeth The phase shifts (rotates) by two teeth with respect to the gear 70. This “shift”, that is, the rotation of the external gear 60,
Is transmitted to the flange portion 81 and the support ring 82 of the output shaft (second shaft) 80 connected to the output shaft through the shaft. The rotational force transmitted to the support ring 82 is collected on the flange portion 81 of the output shaft 80 by the three carrier pins 90 (91, 92, 93).

As a result, in the second-stage speed reduction mechanism S2, when the distribution shaft 40 makes one rotation, the output shaft 80 rotates in the direction opposite to the rotation direction of the distribution shaft 40 (the same direction as the input shaft 10).
Will be rotated by 2/58. In this manner, in this internally meshing planetary gear structure, the sun gear 20 and the planetary gear 30 are meshed by the first-stage reduction mechanism S1, and thus (the number of teeth of the sun gear 20 = 12) / (the teeth of the planetary gear 30). Number = 3
Since the reduction ratio of (6) is obtained, and the reduction ratio of (2/58) is obtained by the second-stage reduction mechanism S2, (12/36) × (2/58) = 1 / A total reduction ratio of 87 would be obtained.

Such a distributing type internal meshing planetary gear structure can obtain a high reduction ratio with a small number of components, and is therefore widely used, for example, in a drive system of an industrial robot.

In the conventional example, the first shaft (input shaft 1)
0) to reduce the rotation input from the second shaft (output shaft 8).
Although the present invention is applied to the "reducer" extracted from 0), the above structure can be applied to the "speed increaser" by reversing the input / output relationship between the first axis and the second axis. Hereinafter, the term "deceleration" will be used for convenience, but this concept includes the concept of "increased speed" when input and output are reversed.

[0010]

SUMMARY OF THE INVENTION A first-stage speed reduction mechanism S in this type of distributing type internally meshing planetary gear structure.
The one sun gear 20 and the planetary gear 30 have a function of decelerating and distribute the rotational force of the input shaft (first shaft) 10 to a plurality of (three in the example of FIGS. 4 to 6) distribution shafts 40. ”. That is, the second stage reduction mechanism S2 cannot receive the power itself unless the power is distributed by the sun gear 20 and the planetary gear 30 of the first stage reduction mechanism S1. Therefore, the first-stage speed reduction mechanism S1 and the second-stage speed reduction mechanism S2 are not allowed to have free dimensions, and mutually restrict the dimensions.

The reduction ratio of the first-stage reduction mechanism S1 is practically 1
The limit is about / 5. However, the speed reduction of the second-stage speed reduction mechanism S2 is 1/1 when the difference in the number of teeth between the external gear 60 and the internal gear 70 is “2” as shown in FIGS.
30, when the difference in the number of teeth is "1" as in JP-A-60-260737, about 1/60 can be easily obtained.

As described above, since the first-stage speed reduction mechanism S1 cannot obtain a large reduction ratio, the transmission torque is small.
The second-stage speed reduction mechanism S2 receives the torque amplified by the first-stage speed reduction mechanism S1 and decelerates the torque at a larger reduction ratio, so that the transmission torque becomes very large. for that reason,
In the second stage reduction mechanism S2, in order to handle this large transmission torque, the radius R1 of the arrangement circle of the three distributing shafts 40 is usually larger (as large as possible is advantageous).
Is set to about 1/2 of the radius R2 of the pitch circle.
However, the radius R1 of the arrangement circle of the sorting shaft 40 is
Due to the restriction of the distribution structure, the center distance R3 between the sun gear 20 and the planetary gear 30 of the first-stage speed reduction mechanism S1 is kept as it is.
Must be equal to That is, there is a restriction that R1 = R3 must be satisfied.

This means that the first-stage speed reduction mechanism S1
Despite handling only a much smaller torque than the transmission torque of the speed reduction mechanism S2 at the stage (though from the point of torque transmission, a gear pair having a center-to-center distance smaller than R3 is sufficient). Larger than necessary (same size as R1) due to the relationship with the size of the second-stage speed reduction mechanism S2
This means that the distance between the centers has become R3.

In general, it is known that the noise of a gear transmission device increases in proportion to the peripheral speed at the mesh point when the type of gear and the machining accuracy are the same. That is,
The known internally meshing planetary gear structure has a gear pair of an unnecessary size in the first stage (high-speed side) for power transmission.
There is a problem that the gear noise of the speed reduction mechanism S1 at the first stage becomes extremely large, and therefore, there is a serious problem that it cannot be incorporated into a system that requires low noise.

The present invention has been made in view of such a conventional problem, and an (distribution type) internally meshing planetary gear structure capable of realizing low noise with a simple and low-cost configuration. The purpose is to provide.

[0016]

SUMMARY OF THE INVENTION The present invention provides a first shaft connected to an external member, and a plurality of shafts arranged on a circumference concentric with the first shaft and rotating in conjunction with the first shaft. A sorting axis,
An eccentric body provided on each of the plurality of distribution axes,
An external gear that is rotatable eccentrically with respect to the first shaft by being fitted to the eccentric body, and is incorporated concentrically with the first shaft, and the external gear is attached to the first shaft. In an internally meshing planetary gear structure including an internal gear that meshes internally while rotating eccentrically, and a second shaft that is connected to the plurality of distribution shafts, a sun roller provided on the first shaft is provided. A plurality of planetary rollers provided on each of the plurality of sorting shafts, each circumscribing the sun roller, and having an inner diameter slightly smaller than the diameter of a circle circumscribing all of the plurality of planetary rollers, The above problem has been solved by providing a pressurized ring incorporated so as to be inscribed therein.

In the present invention, both the functions of deceleration and power distribution in the first-stage speed reduction mechanism are realized by friction transmission between the sun roller and the planetary roller, instead of being realized by meshing the gears as in the prior art. I made it. Torque transmission by friction conduction requires a smaller amount of torque transmission than torque transmission by gear meshing.
The transmission torque to be transmitted in the stage reduction mechanism is
There is no particular problem because it is smaller than the (unchangeable and large) inter-axis dimension or roller dimension in the stage reduction mechanism.

On the other hand, by forming the first-stage speed reduction mechanism by friction conduction, the generation of noise can be suppressed to an extremely low level.

By the way, as described above, 1
If the torque transmission of the stage reduction mechanism is realized,
A new problem arises in how to generate a pressurization for generating a frictional force between the rollers for realizing the frictional conduction.

This kind of pressurization is generally given by setting the distance between the rollers slightly smaller than the sum of the respective radii of the rollers in contact with each other.
However, if the rollers are made of metal (however, the necessary transmission torque cannot be secured even if the elastic material such as rubber is the first step), the distance between the shafts (the distance between the centers of the shafts) or the two rollers If the sum of the radii slightly changes due to a manufacturing error (assembly error) or the like, there is a problem that the applied pressure changes very greatly with the change.

That is, when the distance between the axes is slightly reduced,
The applied pressure increases dramatically, and not only transmission loss increases, but also noise and vibration tend to increase. Conversely, if the distance between the shafts is slightly increased, the applied pressure is sharply reduced and slip occurs, so that the torque cannot be transmitted satisfactorily.

However, in this type of distributing type internal meshing planetary gear structure, the distributing shaft into which the planetary roller is incorporated not only serves as a support base for eccentrically rotating the external gear, but also for the external gear. With the rotation, each distribution shaft must rotate around the input shaft integrally. Therefore, the variation of the center distance between each planetary roller and the sun roller is "contained within a tolerance where a predetermined frictional force is generated".
That is virtually impossible.

In the present invention, in order to solve this (newly expected) problem, the pressurizing for generating the frictional force between the rollers is not performed by adjusting the center-to-center distance, but by a pressurizing ring. Is given by

That is, the pressurized ring is connected to the sun roller 12.
It has an inner diameter slightly smaller than the sum of the diameter of 0 and twice the diameter of the planetary rollers 130 (slightly smaller than the diameter of a circle circumscribing all the planetary rollers), and is incorporated so that all the planetary rollers are inscribed. When the preload is applied by this method, the degree of the change in the preload actually generated is much smaller (even with the same machining error or assembly error) than the method of applying the preload by adjusting the center distance. Is obtained.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a partial cross-sectional view showing a geared motor GM to which an internally meshing planetary gear structure according to the present invention is applied, and FIG. 2 shows the configuration of a first-stage speed reduction mechanism S101 shown by an arrow II in FIG. FIG. 3 is a schematic sectional view taken along the line III-III in FIG. 1 showing the configuration of the second-stage speed reduction mechanism S102.

In FIG. 1, the output shaft 102 of the motor M
Is a first-stage speed reduction mechanism S1 via a coupling 104.
01 is connected to an input shaft (first shaft) 110.

A sun roller 120 is fixed to the input shaft 110 via a spline (not shown). As shown in FIG. 2, around the sun roller 120, three sorting shafts 140 (141, 142, 143) are arranged concentrically with the sun roller 120 (that is, concentric with the input shaft 110). I have. Each of the sorting shafts 140 has a planetary roller 130 (131, 1
32, 133) are splines 131a, 132a, 13
Attached via 3a. Therefore, the planetary roller 1
Although 30 is integral with the distribution shaft 140 in the rotation direction, it is configured to be slightly movable in the radial direction.

A pressurizing ring 137 is wound around the three planetary rollers 130. This pressurized ring 137
Has a free inner diameter (inner diameter before assembling) Di smaller than the length obtained by adding twice the diameter Ds of the sun roller 120 and twice the diameter Dp of the planetary roller 130, and has an appropriate flexibility. And can be easily elastically deformed. The pressurizing ring 137 can be easily assembled by deforming the pressurizing ring 137 radially inward at positions P1, P2 and P3 in FIG. This pressurizing ring 137
It simply rotates freely outside each planetary roller 130. That is, only the work of applying a pressurization between the sun roller 120 and the planetary roller 130 is performed, and it does not particularly contribute to the rotation of the two and does not restrict. The planetary roller 130 is pressed against the sun roller 120 with a predetermined pressing force by the pressurizing ring 137, and a predetermined frictional force is generated between the two.

The structure of the second-stage speed reduction mechanism S102 using the distribution shaft 140 as an input shaft is basically the same as that shown in FIGS. 4 to 6 except that the external gear 160 has a single structure. It is substantially the same as the structure provided. Therefore, in FIGS. 1 and 3, parts or members corresponding to those in FIGS. 4 and 6 are denoted by the same reference numerals as those in FIGS. 4 and 6, and the repeated description is omitted.

Next, the operation of the geared motor GM will be mainly described focusing on the operation of the first-stage speed reduction mechanism S101 different from the conventional one.

The power transmission by the first-stage speed reduction mechanism S101 in the geared motor GM replaces the conventional power transmission by gear engagement with the sun roller 120 and the planetary roller 13.
This is done by friction conduction with zero. That is, the input shaft 110
When the sun roller 120 rotates through the spline 125 due to the rotation of the planetary gears, the planetary roller 130 in contact with the sun roller 120 rotates, and the splines 131a, 132a,
Power is transmitted to the distribution shaft 140 via 133a.

Here, since the pressurizing ring 137 is wound around the outer circumference of the planetary roller 130 with the interference δ,
A pressing force (pressing force) Ps is generated between the sun roller 120 and the planetary roller 130, and a pressing force Pi is generated between the planetary roller 130 and the pressurizing ring 137. The pressing force Ps generated between the sun roller 120 and the planetary roller 130 generates a load due to the Hertz deformation of the respective rollers 120 and 130, and generates a pressing force generated between the planetary roller 130 and the pressurizing ring 137. The force Pi is the planetary roller 1
In addition to applying a deformation of Hertz to 30, the pressurizing ring 137 generates a load due to the bending of the tension as a bending tension together with the deformation of the Hertz. This tension bending is a huge deformation with a different order of magnitude compared to the Hertz deformation.

The deformation of the sun roller 120 and the planet 130 due to the pressurization causes an error in the center-to-center distance, but does not affect the center-to-center distance of each of the sorting shafts 140 due to the loose fitting structure by spline connection.

The pressing force (pressurizing force) Ps between the rollers 120 and 130 hardly acts on the input shaft 110 and its bearing 111 because of the loose fitting structure by the spline connection.

As described above, since the tension bending component is included in the deformation generated by each load, the sun roller 120 and the planetary gears are protected against dimensional changes caused by processing errors and wear of the roller diameter and the pressurized ring inner diameter. The change in the pressure contact force (pressurizing force) Ps between the roller 130 and the roller 130 becomes insensitive, and a predetermined pressurizing force can always be secured.

The geared motor GM is provided with a first-stage speed reduction mechanism S1 which has conventionally been a source of loud noise.
01 is realized by friction transmission, and a pressurizing force for generating a frictional force on the sun roller 120 and the planetary roller 130 is obtained not by adjusting the distance between the shafts but by winding the pressurizing ring 137. Accordingly, the applied pressure does not greatly change depending on a processing error, an assembly error, or a dimensional change caused by wear, and stable power transmission can always be performed.

Furthermore, since the continuous power transmission can be performed by the frictional force of the toothless roller instead of the discontinuous power transmission by the meshing of the gears, the torque output from the output shaft 170 can be further stabilized. Is also obtained.

[0039]

As described above, according to the present invention,
The power transmission of the first-stage reduction mechanism of the distributing type internally meshing planetary gear structure is realized by friction conduction, and the application of a pressure to each roller for performing the friction transmission is performed (not by adjusting the shafts). ) Because the pressurizing ring is incorporated, there is an excellent effect that a stable pressurizing can always be secured without being largely affected by processing errors, assembling errors, or changes over time. can get.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a geared motor to which an internally meshing planetary gear structure according to the present invention is applied.

FIG. 2 is a schematic sectional view taken along the line II-II of FIG.

FIG. 3 is a schematic sectional view taken along the line III-III in FIG. 1;

FIG. 4 is a cross-sectional view showing an example of a speed reducer to which a conventional internally meshing planetary gear structure is applied.

FIG. 5 is a schematic enlarged sectional view taken along the line VV of FIG. 4;

FIG. 6 is a schematic cross-sectional view taken along line VI-VI of FIG. 4;

[Explanation of symbols]

 110 input shaft (first axis) 120 sun roller 130 planetary roller 137 pressurizing ring 140 distribution shaft 150 eccentric body 160 external gear 170 internal gear 180 output shaft (second axis)

Claims (1)

[Claims] A first shaft connected to an external member; a plurality of sorting shafts arranged on a circumference concentric with the first shaft and rotating in conjunction with the first shaft; and a plurality of sorting shafts. An eccentric body provided on each of the shafts; an external gear that is rotatable eccentrically with respect to the first shaft by being fitted to the eccentric body; and incorporated concentrically with the first shaft; The external gear is the first
An internal gear that internally meshes while rotating eccentrically with respect to a shaft, and a second shaft that is connected to the plurality of distribution shafts, wherein the internal gear is configured to be provided on the first shaft. A sun roller, a plurality of planetary rollers provided on each of the plurality of sorting shafts, each circumscribing the sun roller, and an inner diameter slightly smaller than the sum of the diameter of the sun roller and twice the diameter of the planetary roller. And a pressurizing ring which is incorporated so that the planetary roller is inscribed therein.