JP2523068Y2 - Inner mesh planetary gear structure - Google Patents

Description

[Detailed description of the invention] [Industrial applications]

The present invention relates to an internally meshing planetary gear structure suitable for being applied to a speed reducer or a speed-increasing gear, in particular, a small speed-reducing or speed-increasing device requiring a high output.

[Prior art]

Conventionally, via a first shaft and an eccentric body provided on the first shaft,
A plurality of external gears eccentrically mounted on the first shaft, an internal gear in which the external gear meshes internally, and means for transmitting only the rotation component of the external gear to the external gear And an internal meshing planetary gear structure including a second shaft connected via a shaft. FIGS. 4 and 5 show a conventional example of this structure. In this conventional example, the first shaft is used as an input shaft, the second shaft is used as an output shaft, and the above structure is applied to a "reduction gear" by fixing an internal gear. The eccentric bodies 3a and 3b are fitted to the input shaft 1 with a predetermined phase difference (180 ° in this example). The eccentric bodies 3a and 3b are integrated. Rollers 4 for each eccentric 3a, 3b
, Two external gears 5a and 5b are attached. The external gears 5a and 5b are provided with a plurality of inner roller holes 6,
The inner pin 7 and the inner roller 8 are fitted. On the outer periphery of the external gears 5a and 5b, external teeth 9 such as a trochoid tooth shape and an arc tooth shape are provided. The external teeth 9 are internally meshed with an internal gear 10 fixed to the casing 12. Specifically, the internal teeth of the internal gear 10 have a structure in which the outer pin 11 is loosely fitted into the outer pin hole 13 and is easily rotated. The inner pin 7 passing through the external gears 5a and 5b is
Is fixed or fitted to the flange portion 14. When the input shaft 1 makes one rotation, the eccentric bodies 3a and 3b make one rotation.
By one rotation of the eccentric bodies 3a and 3b, the external gears 5a and 5b also try to oscillate around the input shaft 1.
The external gear 5a, 5b
Performs almost only swing while inscribed in the internal gear 10. Now, for example, if the number of teeth of the external gears 5a and 5b is N and the number of teeth of the internal gear 10 is N + 1, the difference in the number of teeth is 1. Therefore, each time the input shaft 1 rotates once, the external gears 5a and 5b shift (rotate) by one tooth with respect to the internal gear 10 fixed to the casing 12. This means that one rotation of the input shaft 1 has been reduced to -1 / N rotation of the external gear. The rotation of the external gears 5a and 5b is absorbed by the gap between the inner roller hole 6 and the inner pin 7, and only the rotation component is transmitted to the output shaft 2 via the inner pin 7. . As a result, a reduction ratio of −1 / N is achieved. In this conventional example, the internal gear of the internal meshing planetary gear structure is fixed, the first shaft is used as the input shaft, and the second shaft is used as the output shaft. However, the second shaft is fixed and the first shaft is used. The reduction gear can also be configured by using the input shaft and the internal gear as the output shaft. Further, it is also possible to configure a speed increaser by reversing these inputs and outputs.

[Problems to be solved by the invention]

However, the internal meshing planetary gear structure as described above has the following problems. As shown in FIG. 6, when the loads acting on the input shaft 1 and the output shaft 2 are considered, the rotational load W1 that the output shaft 2 receives from the input shaft 1 is, as is clear from the figure, the end position of the bearing 15b. Is acting on. The load W2 which the output shaft 2 receives from the external gear (not shown in FIG. 6) acts on the inner pin 7 as shown. Further, the input shaft 1 is connected to the external gear 5
The load W3 received from a and 5b acts on the input shaft 1 as shown. As a result, the loads W1 and W2 acting on the output shaft 2 are
Since the input shaft 1 is located closer to the input shaft 1 than a and 16b, the output shaft 2 is just cantilevered and receives the loads W1 and W2,
The moment inclines by the angle α with respect to the normal axis O1. Also, the load W3 acting on the input shaft 1 is coupled with the inclination of the output shaft 2, and the moment of the input shaft 1 makes the input shaft 1 a regular shaft center
Incline by an angle β with respect to O1. For this reason, the input shaft 1 and the output shaft 2 rotate while their axes are shifted from each other, causing abnormal wear, noise, and vibration. Also, as shown in FIG. 7, when a radial load F is applied to the input shaft 1 from the outside, the input shaft 1 is inclined by β ′ with respect to the normal shaft center O1 in the same manner as described above. In addition, the output shaft 2 is inclined by α 'with respect to the normal shaft center O1, and this inclination also causes a reduction in service life. The inclination of the output shaft 2 or the input shaft 1 is such that the input shaft 1 receives the load W3 from the external gears 5a, 5b via the eccentric bodies 3a, 3b, and supports the load W3 with the bearings 15a, 15b of the input shaft 1. It is due to that. In the conventional internal meshing planetary gear structure as described above, the load is balanced by equally distributing the transmission torque to the external gears 5a and 5b, but the two external gears 5a , 5b are not on the same plane, the moment acting on the eccentric bodies 3a, 3b due to the load acting on each external gear 5a, 5b (couple)
(See FIG. 4). The moment acting on the eccentric bodies 3a and 3b is
Since this is the product of the load acting on 5a and 5b and the distance between the two external gears 5a and 5b, the distance can be reduced by reducing the distance between the two external gears 5a and 5b. . However,
The external gears 5a, 5b are supported by eccentric bodies 3a, 3b and rollers 4, and the eccentric bodies 3a, 3b and rollers 4 need a predetermined length depending on the load capacity in terms of strength, and the distance between them is reduced. There are limits to what you can do. The present invention has been made in view of such a conventional problem, and in particular, favorably absorbs the radial eccentric load generated between the external gear, the eccentric body, and the first shaft, thereby reducing the life. It is an object of the present invention to provide an internally meshing planetary gear structure which is prevented as much as possible.

[Means for Solving the Problems]

According to the present invention, a first shaft, a plurality of external gears mounted eccentrically to the first shaft via an eccentric body provided on the first shaft, and an internal gear in which the external gears mesh internally. In an internally meshing planetary gear structure comprising a tooth gear and a second shaft connected to the external gear through a means for transmitting only the rotation component of the external gear, the inner diameter of the eccentric body is The eccentric body is set to be larger than the outer diameter of the first axis, and the eccentric body is coupled to the first axis so as to be displaceable in the radial direction within a range smaller than the eccentric amount. A positioning member capable of restraining the movement of the eccentric body on the first axis in the axial direction and receiving a moment in which the eccentric body is inclined with respect to the axis of the first axis is disposed, and the positioning member and the positioning member The gap with the eccentric body was managed so as to be a predetermined gap set in advance. By a, it is obtained by achieving the above object.

[Action]

In the present invention, first, the eccentric body is coupled to the first shaft so that the eccentric body can be displaced in the radial direction within a range that does not impair the internal meshing rotation function of the external gear. Specifically, the inner diameter of the eccentric body is set larger than the outer diameter of the first shaft, and the eccentric body is coupled to the first shaft so as to be displaceable in the radial direction within a range smaller than the eccentric amount. ing. This makes it possible to absorb the problem that the axis is shifted due to the load from the external gear by the flexible connection between the eccentric body and the first shaft. By the way, if the eccentric body and the first shaft are simply flexible-coupled, a thrust force due to a moment is generated in the eccentric body due to the above-mentioned reason, and the eccentric body can be positioned on the first shaft in a satisfactory manner. Not done. Further, depending on the generated moment, the eccentric body and the first shaft are likely to come into contact with each other in an impact, or the whirling is apt to occur, which may induce abnormal wear, noise and vibration. Therefore, in the present invention, a positioning member is attached to the eccentric body, and the positioning member restricts the axial movement of the eccentric body on the first axis, and the eccentric body is inclined with respect to the axis of the first axis. The positioning moment is received by the positioning member. In addition, in the present invention, the gap between the positioning member and the eccentric body is managed so as to be a predetermined gap set in advance. That is, it is generally difficult to keep the gap between the positioning member and the eccentric body constant due to variations due to processing and assembly errors, changes in the gap due to sliding friction, and the like. If the gap is too large, the eccentric body is floated from the first axis, so that the eccentric body and the first axis or the eccentric body and the positioning member are likely to come into contact with each other depending on the generated moment. And the noise and vibration increase due to large swings. On the other hand, if the gap is too small, the sliding resistance and the sliding friction increase, and power transmission loss, seizure, and the like are likely to occur. Therefore, in the present invention, the gap between the eccentric body and the positioning member is managed, and the gap is set to a predetermined value. As a result, the eccentric body can be favorably positioned on the first axis, and a radial (eccentric) load generated from the eccentric body to the first axis can be effectively suppressed. It is possible to almost completely prevent new abnormal wear and the like caused by the flexible connection with the first shaft.

【Example】

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, the “first shaft” is used as the input shaft, the “second shaft” is used as the output shaft, and the “internal gear” is fixed, so that the internal meshing planetary gear structure is called “reduction gear”. It is applied to In addition, by fixing the "first shaft" as the input shaft and the "internal gear" as the output member, and fixing the "second shaft", the internal meshing planetary gear structure can also be applied to the speed reducer. . Further, by inverting these input / output relations, the present invention can be applied to a gearbox. In FIG. 1, a hollow eccentric shaft 23 is inserted into an input shaft 21. The eccentric body shaft 23 has an inner diameter set to be larger than the outer diameter of the input shaft 21 and is connected to the input shaft 21 by flexible coupling means 24 such as spline coupling or Oldham coupling that absorbs displacement in the radial direction. This eccentric shaft
23 has two eccentric bodies 23a and 23b. Two external gears 25a, 25b are mounted on the eccentric bodies 23a, 23b, bearings 26a, 26b.
And can be rotated while swinging by an amount corresponding to the amount of eccentricity of the eccentric bodies 23a and 23b. The amount of radial displacement of the eccentric body shaft 23 and the input shaft 21 by the flexible coupling means 24 is determined by the eccentric bodies 23a and 23a.
The eccentric amount is smaller than the eccentric amount of 3b, and has a size that does not impair the internal meshing rotation function of the external gears 25a and 25b. The external gears 25a and 25b have external teeth having a trochoidal tooth profile on the outer periphery thereof, and are internally meshed with the internal gear 28. The internal gear 28 is formed integrally with the casing 27. Further, the internal gear 28 has an arcuate tooth shape composed of an external pin 29 that meshes with the external gears 25a and 25b. An internal pin hole 30 is formed in the external gears 25a and 25b, and a hole pin 31 is loosely fitted in the internal pin hole 30. An inner roller 32 is loosely fitted around the outer periphery of the inner pin 31. The swing of the external gears 25a and 25b is absorbed by this loose fit. However, the inner roller 32 can be omitted. Both ends of the inner pin 31 are closely fitted to the inner pin holding rings 33a and 33b. Inner pin retaining rings 33a and 33b are external gear 25
The inner pin holding ring 33b is provided on both sides of the output shaft a and 25b, and is connected to the output shaft 22. Here, a distance piece (positioning member) 34a is supported on the inner pin holding ring 33a via a bolt 37. A distance piece 34b is fitted in the inner pin holding ring 33b. Eccentric body shaft 23 (eccentric body 23
a, 24a) are clamped by the two distance pieces 34a, 34b, the axial movement on the input shaft 21 is restricted, and the reaction force of the moment tending to tilt with respect to the input shaft 21 is It can be received from the distance pieces 34a, 34b. The reason that the distance piece 34a is easily detachably assembled with the bolt 37 is that the distance piece 34a can be removed and the gap 37 between the eccentric body shaft 23 and the two distance pieces 33a and 33b can be adjusted. In particular,
Several types of distance pieces 34b with slightly different thicknesses D are prepared in advance, which are cut and adjusted so that the gap becomes the set value during assembly, and variations in the gap size due to manufacturing variations or wear. For example, a proper gap may be secured by appropriately replacing and assembling according to the above. Next, the operation of this embodiment will be described. Moments are generated in the eccentric shaft 23 (eccentric bodies 23a and 23b) by the loads acting on the two external gears 25a and 25b. However, since this moment is received by the distance pieces 34a and 34b on the side surfaces of the eccentric body and the axial displacement is restrained, the eccentric body shaft 23 is prevented from applying an eccentric load in the radial direction to the input shaft 21. Is done. In addition, since the eccentric shaft 23 and the input shaft 21 have a flexible joint structure that can be displaced in the radial direction such as a spline joint or an Oldham coupling, the support system according to this embodiment requires the eccentric shaft 23 and the input shaft 21 In addition to the radial load, not only the radial load is not applied, but also the radial load itself is hardly applied. Therefore, except for the torsional load due to the rotational torque, the input shaft 21 does not have any radial load acting thereon, so that there is no generation of vibration or noise based on the torsional bending phenomenon of the input shaft 21, and also the bearings supporting the input shaft 21. It is possible to reduce the size or omit the bearing. FIG. 2 shows another embodiment of the present invention. In this embodiment, a single distance piece 38a is used and the distance piece 38a is used.
A shim 36 is inserted between 38a and the inner pin holding ring 34b, and the shim 36 having a proper thickness is used. Other configurations are the same as those of the first embodiment. FIG. 3 shows still another embodiment of the present invention. In this embodiment, screws 44 of the same pitch are cut on the outer peripheral side of the distance piece 40 and the inner peripheral side of the inner pin holding ring 42. The gap adjustment is performed by moving the distance piece 40 along the screw 44. Proper gap
When the number reaches 37, the position is fixed by the washer 46 and the nut 48. The present invention is not limited to the above embodiment, but can be applied to various types of internally meshing planetary gear structures as described above.

[Effect of the invention]

As described above, according to the present invention, the presence of the positioning member enables the moment generated in the eccentric body to be satisfactorily received from the side direction, thereby preventing the eccentric body from tilting. As a result, the radial load acting on the first shaft can be almost eliminated, coupled with the fact that the eccentric body and the first shaft are formed as a flexible connection that can be displaced in the radial direction, and vibration based on the whirling phenomenon of the first shaft is achieved. And noise can be prevented, and the bearing that supports the input shaft can be downsized or omitted. Further, in the present invention, since the gap between the eccentric body and the positioning member is controlled to a predetermined value, the above-mentioned effect can be realized smoothly without causing abnormal wear and transmission loss.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a speed reducer to which the internally meshing planetary gear structure according to the present invention is applied, and FIGS. 2 and 3 are schematic longitudinal sectional views showing other embodiments of the present invention. FIG. 4 is a longitudinal sectional view showing an example of a conventional speed reducer utilizing an internally meshing planetary gear structure, FIG. 5 is a sectional view taken along the line VV in FIG. 4, FIG. 6 and FIG. FIG. 7 is a partial schematic cross-sectional view for explaining a problem of a conventional internal meshing planetary gear structure. 21 ... input shaft (first axis), 22 ... output shaft (second axis), 23
…… Eccentric body (shaft), 24 …… Flexible coupling means, 25
a, 25b ... external gear, 26a, 26b ... bearing, 28 ... internal gear, 29 ... external pin, 30 ... internal pin hole, 31 ... internal pin, 32
…… Inner roller, 33a, 33b, 42 …… Inner pin retaining ring, 34
a, 34b, 40 ... distance piece, 35 ... flexible coupling means, 36 ... shim.

Claims (1)

(57) [Scope of request for utility model registration] 1. A first shaft, a plurality of external gears mounted eccentrically to the first shaft via an eccentric body provided on the first shaft, and the external gear internally meshed. An internally meshing planetary gear structure including an internal gear and a second shaft connected to the external gear through a unit that transmits only the rotation component of the external gear, wherein an inner diameter of the eccentric body is The eccentric body is set to be larger than the outer diameter of the first shaft, and the eccentric body is coupled so as to be displaceable in the radial direction with respect to the first shaft within a range smaller than the eccentric amount. A positioning member that can restrain an axial movement on the first shaft and that can receive a moment when the eccentric body is inclined with respect to the axis of the first shaft is arranged; The gap between the eccentric body and the eccentric body is managed so as to be a predetermined gap set in advance. Internally meshing planetary gear structure, characterized in that the.