JP2509108Y2 - Internal mesh planetary gear structure - Google Patents

Description

[Detailed description of the device] [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. A conventional example of this structure is shown in FIGS. 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). Each eccentric 3
a and 3b are integrated. Two external gears 5a and 5b are attached to the eccentric bodies 3a and 3b via rollers 4, respectively. A plurality of inner roller holes 6 are provided in the external gears 5a and 5b, and inner pins 7 and inner rollers 8 are fitted therein. 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 the 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 in the outer pin hole 13 so as to be 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
Almost swings 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, 5b is absorbed by the swing component due to 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 through 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 device]

However, the internal meshing planetary gear structure as described above has the following problems. As shown in FIG. 4, when the loads acting on the input shaft 1 and the output shaft 2 are considered, the rotational load W1 received by the output shaft 2 from the input shaft 1 is, as is apparent from the drawing, the end position of the bearing 15b. Is working on. The load W2 which the output shaft 2 receives from the external gear (not shown in FIG. 4) acts on the inner pin 7 as shown. Further, the input shaft 1 is an 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. Further, as shown in FIG. 5, even 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. Further, the output shaft 2 is inclined by α'with respect to the regular shaft center O1, and this inclination also causes abnormal wear, noise and vibration. 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)
Occurs (see FIG. 2). 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 the eccentric bodies 3a, 3b and the rollers 4, and the eccentric bodies 3a, 3b and the rollers 4 require a predetermined length depending on the load capacity in terms of strength, and the interval between them is shortened. There are limits to what you can do. The present invention has been made in view of such a conventional problem, and particularly, it favorably absorbs an eccentric load in the radial direction generated between the external gear, the eccentric body, and the first shaft, and thus abnormal wear and noise are caused. It is an object of the present invention to provide an internally meshing planetary gear structure that reduces vibration as much as possible.

[Means for Solving the Problems]

The present invention is directed to a first shaft, a plurality of external gears mounted in an eccentric manner on the first shaft via an eccentric body provided on the first shaft, and an internal mesh for internally meshing the external gears. A toothed gear, an inner pin hole formed in the outer gear, an inner pin loosely fitted in the inner pin hole, and an inner pin holding ring for holding the inner pin,
In an internally meshing planetary gear structure including a second shaft connected to the inner pin holding ring, an inner diameter of the eccentric body is set to be larger than an outer diameter of the first shaft, and the inner pin holding ring is Provided on both sides of the external gear by sandwiching the external gear, between one of the inner pin retaining ring and the eccentric body,
A thrust bearing for restraining the axial movement of the eccentric body to one side of the inner pin holding ring is provided, and the eccentric body is arranged between the first shaft and the eccentric body in a range smaller than the eccentric amount. It is possible to displace in the radial direction with respect to the first axis with
The above object is achieved by providing a shaft joint which also functions as a thrust bearing for restraining axial movement of the eccentric body to the other side of the inner pin holding ring. When the external gear is fitted to the eccentric body through two angular bearings arranged so that the bearing action lines are in the directions facing each other, two external gears are provided. It is possible to substantially shorten the interval between the two, and it is possible to further reduce the generated moment itself.

[Action]

In the present invention, first, the inner diameter of the eccentric body is set larger than the outer diameter of the first shaft so that the eccentric body can freely move in the radial direction with respect to the first shaft. A thrust bearing is provided between the eccentric body and the inner pin retaining ring to restrain the axial movement of the eccentric body to one side. Then, the eccentric body is connected to the first shaft by a shaft coupling that allows radial displacement within a range that does not impair the internal meshing rotation function of the external gear, specifically, a range smaller than the eccentric amount e. I am trying to do it. Moreover, this shaft joint also has a function of a thrust bearing that prevents the eccentric body from moving toward the other side of the inner pin retaining ring. 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. That is, as a method of absorbing an eccentric load in the radial direction between the eccentric body and the first shaft, it is an effective means to connect the two eccentric bodies flexibly, but it is merely a flexible connection between the eccentric body and the first shaft. Only by doing so, the thrust force due to the moment is generated in the eccentric body due to the reason described above, and the eccentric body is not properly positioned on the first axis. 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, an inner pin holding ring for holding the inner pin is provided on both sides of the outer tooth gear by sandwiching the outer tooth gear, and an eccentric body is provided by providing a thrust bearing between one of the inner pin holding ring and the eccentric body. In addition to restraining the axial movement of one side, the shaft joint is configured to have a function of restraining the axial movement of the other side. As a shaft coupling having such a function, for example, a ball type Oldham shaft coupling can be considered. As a result, the thrust reaction force acting on the eccentric body can be supported by the thrust bearings.
A radial (eccentric) load generated from the eccentric body with respect to the first axis can be effectively suppressed, and
In combination with the flexible connection with the shaft, in the support system according to the present invention, the radial load itself is not transmitted from the eccentric body to the first shaft. Therefore, the radial load acting on the first shaft excluding the torsional load due to the rotational torque is eliminated, so that vibration, noise and generation due to the whirling phenomenon of the first shaft are eliminated, and the size of the bearing supporting the first shaft is small. It can be changed or omitted. Further, when the external gear is supported by the angular bearing in the direction in which the bearing action lines face each other, the gap between the two external gears is substantially shortened and the generated moment itself can be further reduced. become. Further, when such an angular bearing in which the bearing action lines face each other is used, when the load on one external gear increases, the load on the other external gear also increases, so the external gear The gears will have self-centering function. Therefore, the load acting on the external gear is evenly distributed, and in combination with the presence of the thrust bearing, the shoulder contact load is eliminated and abnormal wear, noise, and vibration are reduced.

【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. As is clear from the figure, the eccentric body shaft 23 is formed such that the hollow diameter (inner diameter) is larger than the outer diameter of the input shaft 21, and is displaceable in the radial direction via a well-known ball type Oldham shaft joint 24. It is connected to the input shaft 21. Sign
Reference numeral 24a indicates a centerpiece of the Oldham shaft coupling, and 24b indicates a ball. As is well known, the ball-type Oldham shaft joint 24 has a structure similar to that of a thrust ball bearing, and therefore can receive the thrust force generated from the eccentric body shaft 23. The eccentric body shaft 23 is formed with two eccentric bodies 23a and 23b. Two external gears 25a, 25b are fitted to the eccentric bodies 23a, 23b via angular bearings 26a, 26b.
It can rotate while swinging by the amount corresponding to the eccentricity of 23a, 23b. The angular bearings 26a, 26b are composed of ball bearings and roller bearings and have a function of supporting both axial load and radial load. In this embodiment, the bearing action line Fa,
Fb is set in a direction facing each other. The amount of displacement of the eccentric body shaft 23 and the input shaft 21 in the radial direction by the Oldham shaft joint 24 is determined by the eccentric bodies 23a and 23b.
Is smaller than the amount of eccentricity, and the size is within a range that does not impair the internal meshing rotation function of the external gears 25a and 25b. The externally toothed gears 25a and 25b have outer teeth having a trochoidal tooth profile on the outer circumference thereof as in the conventional case, and are internally meshed with the internally toothed gear 28. The internal gear 28 is formed integrally with the casing 27. In addition, the internal gear 28, the external gear 25a, 25b
It has an arcuate tooth profile composed of an outer pin 29 and an outer roller 29a that mesh with each other. Inner pin holes 30a and 30b are formed in the external gears 25a and 25b, and an inner pin 31 is loosely fitted in the inner pin holes 30a and 30b. 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
It is provided on both sides of a and 25b. One of the inner pin retaining rings 33b and the output shaft 22 is not directly connected, but serves as a flexible connecting means 35 such as spline connection. The flexible coupling means 35 is not for absorbing the swing of the external gears 25a and 25b (this swing is absorbed by the gap between the inner pin 31 and the inner pin hole 30 as described above), This is for absorbing a slight swing of the inner pin holding ring 33b with respect to the output shaft 22. Here, this one inner pin retaining ring 33b and the eccentric body shaft 2
A thrust bearing 34 is arranged between the thrust bearing 34 and the thrust bearing 34. Reference numerals 36 and 37 are bearings of the input shaft 21. Next, the operation of the apparatus 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 thrust bearing 34 and the ball type Oldham shaft coupling 24 on both sides of the eccentric body shaft 23, it is possible to prevent an eccentric load in the radial direction from being applied to the input shaft 21 via the eccentric body shaft 23. To be done. Moreover, the eccentric body shaft 23 and the input shaft 21 are connected to the Oldham shaft coupling 24.
Since the eccentric body shaft 23 has a flexible joint structure that is displaceable in the radial direction with respect to the first shaft, the eccentric body shaft 23 from the eccentric body shaft 23 to the input shaft 21 is radial. Almost no directional load is applied. As a result, the input shaft 21 has no radial load acting except the torsional load due to the rotational torque, and the input shaft 21
The generation of vibration and noise based on the deflection phenomenon of 21 is eliminated, and the bearings 36 and 37 supporting the input shaft 21 can be downsized or omitted. Further, in this embodiment, the external gears 25a, 25b are supported by the angular bearings 26a, 26b of 18 combinations (directions in which the bearing action lines Fa, Fb face each other), so that the two external gears 25a, 25b are supported. It becomes possible to further reduce the generated moment itself by substantially shortening the interval of. Furthermore, in the surface-combined angular bearings 26a and 26b,
Since the bearing action lines Fa and Fb face each other in this manner, for example, when the radial load of the external gear 25a increases, the angular bearing 26a is replaced by the angular bearing 26b.
To be pushed outward (on the side of the output shaft 22), and as a result, the angular bearing 26b is pushed outward so that the load of the external gear 25b increases. Therefore, by providing the front-faced angular bearings 26a, 26b, the external gears 25a, 25b have a self-centering function. Therefore, the loads acting on the externally toothed gears 25a and 25b are equally distributed, and the presence of the thrust bearing 34a and the ball type Oldham shaft coupling 24 eliminates the load on the shoulders, which causes abnormal wear, noise, and vibration. The generation will be further reduced. Further, in this embodiment, the inner pin retaining ring 33b and the output shaft 2
Also in the case of 2, the radial unbalanced load applied to the output shaft 22 can be satisfactorily absorbed because these are flexibly coupled. 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 device]

As described above, according to the present invention, the thrust force acting on the eccentric body is smoothly supported from the lateral direction due to the presence of the thrust bearing that sandwiches the eccentric body (shaft) and the shaft joint that also functions as the thrust bearing. Will be able to. As a result, coupled with the fact that the eccentric body and the first shaft are flexible joints that can be displaced in the radial direction, the radial load acting on the first shaft via the external gear to the eccentric body can be almost eliminated. It is possible to obtain an excellent effect that it is possible to prevent the generation of vibration and noise due to the whirling phenomenon of the first shaft, and it is possible to downsize or omit the bearing that supports the input shaft. Further, when the external gear is supported by an angular bearing in a front combination (directions of bearing action lines facing each other), the bearing action lines are inclined so as to face each other. The substantial interval can be shortened, and the moment itself generated in the external gear and the eccentric body can be reduced accordingly. In this case, since the bearing action lines face each other, if the load of one external gear increases, the load of the other external gear also increases, so that the eccentric body and the external gear itself are self-aligning. Therefore, the load acting on the external gear is evenly distributed, the load on the shoulder is eliminated, and abnormal wear, noise, and vibration are further reduced.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a speed reducer to which an internally meshing planetary gear structure according to the present invention is applied, and FIG. 2 is a longitudinal section showing an example of a speed reducer using a conventional internally meshing planetary gear structure. Fig. 3 is a sectional view taken along the line III-III in Fig. 2, and Figs. 4 and 5 are partial schematic sectional views for explaining the problems of the conventional internally meshing planetary gear structure. Is. 21 ... Input shaft (first shaft), 22 ... Output shaft (second shaft), 23 ... Eccentric body (shaft), 24 ... (Ball type) Oldham shaft joint,
25a, 25b ... External gear, 26a, 26b ... Bearing, 28 ... Internal gear,
29 ... Outer pin, 30 ... Inner pin hole, 31 ... Inner pin, 32 ... Inner roller, 33a, 33b ... Inner pin retaining ring, 34 ... Thrust bearing,
35 ... Flexible coupling means.

Claims (2)

(57) [Scope of utility model registration request] 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 gears internally mesh with each other. An internal gear, an internal pin hole formed in the external gear, an internal pin loosely fitted in the internal pin hole, and an internal pin holding ring for holding the internal pin,
In an internally meshing planetary gear structure including a second shaft connected to the inner pin holding ring, an inner diameter of the eccentric body is set to be larger than an outer diameter of the first shaft, and the inner pin holding ring is Axial movement of the eccentric body to one side of the inner pin holding ring is provided between the inner pin holding ring and the eccentric body, which is provided on both sides of the outer gear and sandwiches the outer gear. Is provided, and the eccentric body is displaceable in the radial direction with respect to the first shaft within a range smaller than the eccentric amount between the first shaft and the eccentric body. An internally meshing planetary gear structure characterized in that a shaft coupling which also functions as a thrust bearing for restraining axial movement of the body to the other side of the inner pin retaining ring is provided. 2. The external gear is fitted to the eccentric body via two angular bearings arranged such that the bearing action lines are in directions facing each other. The internally meshing planetary gear structure according to Item 1.