JP2888675B2 - Inner mesh planetary gear structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internally meshing planetary gear structure suitable for use in a speed reducer or a speed increaser, particularly a speed reducer or a speed increaser which is required to be small in size and low in cost. About.

[0002]

2. Description of the Related Art Conventionally, a first shaft, an external gear mounted eccentrically with respect to the first shaft via an eccentric body provided on the first shaft, and the external gear There is widely known an internally meshing planetary gear structure having an internal gear internally meshed with a second shaft connected to the external gear via means for transmitting only the rotation component of the external gear. Have been.

FIGS. 6 and 7 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.

[0004] An eccentric body 3 is fitted to the input shaft 1 via a key 30. An external gear 5 is mounted on the eccentric body 3 via a bearing 4. The external gear 5 is provided with a plurality of inner roller holes 6, and an inner pin 7 and an inner roller 8 are fitted therein.

[0005] On the outer periphery of the external gear 5, 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 a 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 and held so as to be easily rotated.

The inner pin 7 penetrating the external gear 5 is fixed to a flange 14 of the output shaft 2.

When the input shaft 1 makes one rotation, the eccentric body 3 makes one rotation. By one rotation of the eccentric body 3, the external gear 5 also attempts to oscillate around the input shaft 1.
As a result, the rotation of the external gear 5 is almost limited while the internal gear 10 is in contact with the internal gear 10.

For example, if the number of teeth of the external gear 5 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, the external gear 5 shifts (rotates) by one tooth with respect to the internal gear 10 fixed to the casing 12. This is input shaft 1
This means that the rotation has been reduced to -1 / N rotation of the external gear.

The rotation of the external gear 5 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.

Here, the inner roller hole 6 and the inner pin 7
The (inner roller 8) forms a “constant-speed internal gear mechanism”.

As a result, a speed reduction 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. The reduction gear can also be configured by using one shaft as 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.

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[SUMMARY OF THE INVENTION However, in the conventional this type internally meshing planetary gear structure, the input shaft 1
And the eccentric 3 or 3a, 3b
In addition, since the process is performed by the combination of the key grooves 31 and 32, not only the number of processing steps and the number of parts are increased, but also the processing itself is performed by end milling, so that there is a problem that efficiency is low and mass productivity is low.

Another problem is that stress concentration is likely to occur in the key grooves 31 and 32. For this reason, there has been a demand that the diameter of the input shaft 1 be as large as possible. However, in order to realize compactness in the radial direction of the speed reducer, there is a strong limitation in increasing the outer diameter of the eccentric body. However, there is a demand for securing the thickness of the key groove 32, and there is a limit in increasing the diameter of the input shaft 1.

As a method of positioning two coaxial or substantially coaxial members in the circumferential direction (so-called detent), a part of the outer periphery of the inner member is cut parallel to the axial direction to reduce the cross section. Forming a substantially D-shaped cut part,
A technique for performing positioning in the circumferential direction between the inner member and the outer member by using the cut portion (see FIG. 4) is described below.
It is known as a general purpose technology.

However, such a structure is combined with the input shaft 1 and the eccentric bodies 3, 3a, 3 of this kind of internally meshing planetary gear structure.
In the case of adopting a circumferential positioning structure with the bearing b , according to the conventional idea, the bearing 35 on the output shaft side (generally, a ball bearing is generally used due to cost considerations) 35 The fact is that the diameter must be small enough to be inscribed in the flat part of the part, so that the strength is unacceptable.

That is, this "method of cutting a part of the outer periphery of the input shaft in parallel with the axial direction" is difficult to adopt as a structure applied to this kind of internally meshing planetary gear structure because of its strength. It was a fact.

The present invention has been made in view of such various conventional problems, and has been made in view of such a type of deceleration.
Dare to adopt D-cut coupling in the machine
And to reduce the number of parts so as to avoid having to use a key to the connection between the first axis results in its eccentric body, yet trouble
It is an object of the present invention to provide an internally meshing planetary gear structure that can reduce the cost and the number of assembling man-hours without causing the generation .

[0030]

SUMMARY OF THE INVENTION The present invention relates to a first shaft, and an external gear mounted eccentrically rotatable with respect to the first shaft via an eccentric body provided on the first shaft. A second internal gear which is connected to the external gear by means of transmitting only a rotation component of the external gear to the external gear;
A shaft, and wherein the second shaft is supported by a bearing incorporated on the first shaft, including a position on the first shaft where the bearing is incorporated. A part of the outer periphery is cut in parallel with the axial direction to form a cut portion having a substantially D-shaped cross section, and the cut portion is used to position the first shaft and the eccentric body in the circumferential direction. performs fit, the inner diameter of the bearing to be incorporated in the first axis, said
Bearing set smaller than the outer diameter of the first axis in a position to be integrated, and, by encapsulating filler cuts remaining between the first shaft and the bearing is obtained by solving the above problems .

[0031]

[0032]

[0033]

According to the present invention, first, transverse surface by cutting a part of the outer periphery parallel to the axis direction to the first axis that form a cut portion of the substantially D-shaped.

The eccentric body has the same hole shape as the cross section of the input shaft including the cut portion, so that it can be positioned (stopped) in the circumferential direction.

As a result, the (conventional) acute angle of the cut portion of the outer diameter of the first shaft and the inner diameter of the eccentric body changes to an obtuse angle, and stress concentration occurs. It became difficult. Further, since there is no key defining the minimum thickness of the eccentric body, the diameter of the first shaft can be further increased, and the outer diameter of the eccentric body can be reduced. In addition to strengthening the strength, the size can be further reduced depending on the application.

Conventionally, the machining of the keyway of the first shaft has to be performed by end milling, so that the machining efficiency is very poor and the mass productivity is poor. However, when such a substantially D-shaped cut portion is formed, In this method, a large number of input shafts can be arranged and broach processing can be performed at the same time, so that the processing efficiency is remarkably improved and the mass productivity is improved. As a result, the cost can be further reduced.

In addition, the number of parts can be naturally reduced due to the absence of the key, and the number of assembling steps is also reduced.

In addition, in the present invention, it is installed on the first shaft.
That the inner diameter of the second shaft side bearing, in a position in which the bearing is incorporated
And the gap at the cut portion is less than the outer diameter of the first shaft .
Set larger than the diameter that would Kunakuna' size, and so as to encapsulate the filler cuts remaining between the resulting first shaft and the bearing.

By doing so, it is possible to minimize a decrease in the strength of the second shaft side bearing portion.

The filler may be a resin, a solder, or the like.

[0041]

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

FIG. 1 is a sectional view of a speed reducer to which an internally meshing planetary gear structure according to the present invention is applied, and FIG.
FIG. 2 is a sectional view taken along line II-II.

In the following description, the same or similar parts as those of the conventional example shown in FIGS. 6 and 7 and FIGS.

One end of a carrier pin (carrier body) 116, which is a member separate from the flange portion 114, is fitted (press-fitted) into the flange portion 114 of the output shaft 102. A support ring 117 is fitted (press-fitted) into the other end of the carrier pin 116, and a carrier is constituted by the support ring 117 and the carrier pin 116.

The flange portion 114, the carrier pin 116,
And the support ring 117 includes a pair of bearings 115a, 115.
b is supported by the casing 112 at both ends.

A pipe-shaped spacer 125 is fitted (press-fitted) into the carrier pin 116 at substantially the center thereof.
Therefore, even if the fitting depth of the carrier pin 116 into the support ring 117 or the flange 114 is slightly varied, the distance between the support ring 117 and the flange 114 is always kept constant by the function of the spacer 125. In addition, the same distance can be easily secured in all the four carrier pins 116.

As shown in FIGS. 3 and 4, a part of the outer periphery of the input shaft 101 is cut in parallel with the axial direction, and a cut portion 140 having a substantially D-shaped cross section is formed. or,
The eccentric body 103 is provided with a hole 141 having the same shape as the cross-sectional shape of the input shaft 101 including the shape of the cut portion 140. By fitting the hole 141, a circle between the input shaft 101 and the eccentric body 103 is formed. Positioning (stopping) in the circumferential direction is performed (FIG. 4).

The relationship between the eccentric direction of the eccentric body 103 and the position of the cut portion is determined in consideration of strength, commonality (especially in the case of a large number of external gears), and the like.

Output shaft side bearing 1 incorporated in input shaft 101
The inner diameter of 35 is a position where the output shaft side bearing 135 is incorporated.
101A made slightly only rather smaller form than the inner diameter of the input shaft 101 in (FIG. 3), the resin filler 136 or solder, is filled to cut the remaining portion (the hatched portion in FIG. 5). This is intended to secure at least a large inner diameter of the bearing 135 on the output shaft side, to prevent a decrease in strength due to the presence of the cut portion, and to suppress dust and iron powder from entering this portion. .

The inner pin 107 is attached to the support ring 11
7 and the flange 114. Therefore,
Free rotation is no longer possible. However, since the shape of the inner pin 107 is a simple columnar shape, high-precision processing can be easily performed using a hard material.
Since a structure is adopted in which the reduction gears are supported at both ends by interposing the reduction mechanism between 15a and 115b, the rigidity of the entire reduction gear can be greatly increased, and the inner pin 107 can be supported in an extremely stable state. And the carrier pin 116, so that the radial load flowing from the output shaft or the like is taken up by the carrier pin 116, and the inner pin 107 is not likely to be subjected to a strong radial load. Since it can be supported in a stable state, there is no particular problem even if the inner roller is omitted in practical use. Note that the inner pin 107 may be configured to be “freely fitted” instead of “press-fitted”.

Next, the operation of this embodiment will be described.

The external gear 105 oscillates with the rotation of the input shaft 101, and meshes with the external pin 111, which corresponds to the internal teeth of the internal gear 110, and the external gear 105, thereby causing the input shaft 101 to rotate.
Is the reduced rotation (rotation) of the external gear 105 in exactly the same manner as in the conventional known example.

The rotation of the external gear 105 is controlled by the rotation of the inner pin hole 1.
The swinging component is absorbed by the gap between the inner pin 107 and the inner pin 107, and only the rotation component is output to the output shaft 1 through the inner pin 107.
02 and the support ring 117. The torque transmitted to the support ring 117 is transmitted to the output shaft 102 via the carrier pin 116.

Since the external radial load acting on the output shaft 102 is received by the bearing 115a and the bearing 115a via the carrier pin 116 and the support ring 117, the external radial load does not affect the inner pin 107. .

Also, the flange portion 114 and the support ring 117
, The external radial load applied to the input shaft 101 is also reduced. As a result, the load on the strength of the bearings 135 and 136 of the input shaft 101, particularly the bearing 135 near the output shaft is reduced. Thus, the diameter of the input shaft 101 in this portion can be reduced, that is, the bearing 135 can be reduced in size. As a result, it is possible to "cut a part of the outer periphery of the input shaft 101 in parallel with the axial direction and use the cut portion to position the input shaft 101 and the eccentric body 103 in the circumferential direction". Was. The advantage of adopting this positioning structure is as described in detail in the section of “Operation”.

The present invention can naturally be applied to a case having two external gears. The example shown in FIG. However, the same or similar parts are given the same reference numerals in the last two digits, and detailed description is omitted.

[0057]

As described in the foregoing, according to the present invention, the coupling structure between the first shaft and the eccentric body to be able to rationally improved overall and to high strength and low cost can be realized.

[Brief description of the drawings]

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

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

FIG. 3 is a front view and a plan view of an input shaft.

FIG. 4 is a cross-sectional view showing a relationship between an input shaft and an eccentric body.

FIG. 5 is a cross-sectional view illustrating a relationship between an input shaft, an eccentric body, and an output shaft side bearing.

FIG. 6 is a sectional view showing a speed reducer to which a conventional internal meshing planetary gear structure is applied.

FIG. 7 is an enlarged sectional view taken along the line VII-VII of FIG. 6;

FIG. 8 is a sectional view showing another embodiment of the present invention .

[Explanation of symbols]

1, 101, 201 ... input shaft, 2, 102, 202 ... output shaft, 3, 103, 203 ... eccentric body, 5, 105, 205 ... external gear, 6a, 6b ... inner roller hole, 7, 107, 207 ... inner pins, 8a, 8b ... inner rollers, 10, 110, 210 ... internal gears, 11, 111, 211 ... outer pins, 14, 114, 214 ... output shaft flanges, 15a, 15b, 115a, 115b, ... 215a, 21
5b: bearing, 16, 116, 216: carrier pin, 17, 117, 217: support ring, 135, 235: output shaft side bearing, 140, 240: cut portion of input shaft, 141: hole of eccentric body.

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Atsushi Ishigaki 6-1, Asahimachi, Obu City, Aichi Prefecture, Nagoya Works, Sumitomo Heavy Industries, Ltd. (56) References JP-A-53-147165 (JP, A) JP-A-63-83432 (JP, A) JP-A-3-255225 (JP, A) JP-A-3-124053 (JP, U) JP-A-1-96552 (JP, U) JP, B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) F16H 1/32

Claims (1)

(57) [Claims] 1. An external gear mounted on a first shaft, eccentrically rotatable with respect to the first shaft via an eccentric body provided on the first shaft, and the external gear inscribed. An internal gear that meshes with
A second shaft connected to the external gear through a unit that transmits only the rotation component of the external gear.
In the internally meshing planetary gear structure in which a shaft is supported by a bearing incorporated on the first shaft, a part of the outer periphery including a position on the first shaft where the bearing is incorporated is parallel to the axial direction. To form a cut portion having a substantially D-shaped cross section. The cut portion is used to position the first shaft and the eccentric body in the circumferential direction, and incorporated into the first shaft . is the inner diameter of the bearing, the bearing is assembled
Is set smaller than the outer diameter of the first shaft at the position where
And, internally meshing planetary gear structure, wherein the encapsulating filler cuts remaining between the first shaft and the bearing.