JPH0627533B2 - Planetary gear reducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) In the present invention, for example, an internal gear is composed of a circular arc tooth profile formed of a pin or a combination of a pin and a roller, and an external gear is composed of epitrochoid parallel curves. It is composed of a trochoidal tooth profile or an arc tooth profile, and the external gear is oscillated by the rotation of the eccentric body fitted to the external gear, and the internal and external gears are internally meshed to reduce the input rotation and output. More specifically, the planetary gear reducer has a hollow eccentric body shaft composed of three eccentric body shafts, and the hollow portion of the eccentric body shaft can be used. And a structure in which the inner diameter of the hollow portion of the eccentric body is increased.

(Prior Art) Various speed reducers using an internally meshing planetary gear mechanism have been proposed. Among these reduction gears, the internal gear has an arcuate tooth profile consisting of a pin or a combination of a pin and a roller, and the external gear has a trochoidal profile consisting of epitrochoid parallel curves. The pin and the inner roller are loosely fitted, and the external gear is oscillated by the rotation of the eccentric body fitted to the external gear, and the internal and external gears are internally meshed to reduce the input rotation (registered trademark). Is well known as. The "cyclo reduction gear" is capable of transmitting a large torque and has a large reduction ratio, so that it is used as various reduction gears.

An example of a known "cyclo speed reducer" (hereinafter referred to as a planetary gear speed reducer) will be described below with reference to FIGS. 3 and 4.

3 is a sectional view showing an example of the planetary gear reducer, and FIG. 4 is a sectional view taken along the line AA of FIG.

In this example, the rotation of the input shaft 1 is extracted as the decelerated rotation of the output shaft 2, but the output shaft 2 may be fixed and the decelerated rotation may be extracted from the internal gear 8. .

The input shaft 1 is provided with two eccentric bodies 3 which are individually divided. The input shaft 1 and the eccentric body 3 have a key structure and a key 4A.
Are joined by. The external gear 5 is an individual eccentric body 3
Are fitted to each other via rollers 6. The external gear 5 has external teeth 7 having a trochoidal tooth profile on its outer circumference.
Further, the roller 6 has an inner peripheral ring 6A. Further, the internal gear 8 also serves as the outer casing, and the internal gear 8 is fixed in this example. The internal gear 8 has an arcuate tooth shape including an external pin 9 that is in mesh with the external gear 5. An internal pin hole 10 is formed in the external gear 5, and an internal pin 11 is loosely fitted in the internal pin hole 10.
An inner roller 12 is loosely fitted to the outer circumference of the inner pin 11, and one end of the inner pin 11 is tightly fitted to the inner pin holding flange 13. The output shaft 2 is integrally provided on the inner pin holding flange 13.

In the planetary gear reducer described above, each eccentric body 3 is attached to the input shaft 1 separately with a phase difference, and in the case of two sheets, it must be attached with a phase difference of 180 degrees. I won't. However, in order to mount it so as to have a phase difference of exactly 180 degrees, precision was required for the work, and workability was not very good.

A planetary gear reducer having a structure as shown in FIG. 5 is also known to improve workability in the work of mounting the eccentric body.

With reference to FIG. 5, an eccentric member 3A formed by integrally molding _two eccentric bodies 3 ₁ and 3 ₂ is provided, and the eccentric member 3A is keyed to the input shaft 1. Other configurations are the same as those of the planetary gear speed reducer shown in FIGS. 3 and 4, and therefore description thereof will be omitted.

According to this structure, the workability is improved in that the labor for adjusting the phase difference of each of the divided eccentric bodies can be saved.

Further, there is also proposed a planetary gear reducer having an eccentric body shaft 3B as shown in FIG. 6 by further advancing the structure shown in FIG.

Referring to FIG. 6, the eccentric body shaft 3B has two eccentric bodies 3 ₁ ,
3 ₂ has integrally, and bearings 14 and 15 at both ends
Is supported by. The bearing 14 is an inner pin holding flange 13
, And the bearing 15 is provided between the bearing 15 and a cover casing 16 fixed to the internal gear 8.

In the planetary gear reducer having the eccentric body shaft 3B, the eccentric body shaft 3B is rotated by an input shaft (not shown), and the rotation of the eccentric body shaft 3B is reduced (when the inner pin holding flange 13 is fixed) or the inner pin. The holding flange 13 is taken out as a decelerated rotation (when the internal gear 8 is fixed).

The hollow portion of the planetary gear reducer shown in FIG. 6 is for inserting the input shaft. The hollow portion of the eccentric body shaft 3B is used, for example, by inserting it into the shaft or by using a required cable. It has been used for various purposes, such as by inserting through.

FIG. 7 shows an example of a robot joint using the planetary gear reduction of the structure of FIG.

Referring to FIG. 7, the rotation of the motor M1 depends on the bevel gears 21, 2
2 to the eccentric body shaft 23 of the first planetary gear reducer. In this first planetary gear reducer, since the internal gear 24 is fixed, the inner pin holding flange 25 is on the output side of the reduced rotation. The inner pin holding flange 25 is a bearing 26
It is rotatably supported by and the rotation of the inner pin holding flange 25 causes the arm 27 of the robot to rotate about the axis O ₁ .

The rotation of the motor M2 is controlled by the bevel gears 28 and 29 via the shaft 3
The rotation of the shaft 30 is 0, and the rotation of the shaft 30 is given to the eccentric body shaft 33 of the second planetary gear reducer via the bevel gears 31 and 32. The shaft 30 is supported by a bearing 34, and the first
Is provided so as to penetrate the eccentric body shaft 23 of the planetary gear reducer. The second planetary gear reducer is provided in the arm 27 of the robot, and the rotation of the eccentric body shaft 33 is output as the decelerated rotation of the inner pin holding flange 35. An operation end 36 of the robot arm 27 is fixed to the inner pin holding flange 35, and the operation end 36 rotates about an axis O ₂ . Therefore, the operating end 36 of the robot is revolved around the axis O _{1 on} the one hand and rotates around the axis O _{2 on the} other hand to perform a predetermined work.

As can be seen from the above description, the conventional planetary gear reducer has a structure in which one or two eccentric bodies are provided.

On the other hand, there is also known a planetary gear reducer in which the number of divided eccentric bodies is three or more to reduce the load acting on each roller and thereby increase the transmission load.

Referring to FIG. 8, the input shaft 1 is provided with three eccentric bodies 3C which are individually divided with a phase difference of 120 degrees. The input shaft 1 and the eccentric body 3C are connected by a key groove and a key as is well known. The three external gears 5 are fitted to the individual eccentric bodies 3C via rollers 6. Roll 6
Has an inner peripheral ring 6A.

The planetary gear reducer provided with the three eccentric bodies 3C has an effect of increasing the transmission load, but if the viewpoint is changed,
Since the transmission load acting on each roller 6 and the inner peripheral ring 6A is small, the thickness of the roller 6 and the inner peripheral ring 6A can be reduced, and the radial size of the planetary gear reducer can be reduced. It can be said that miniaturization can be achieved overall.

(Problems to be Solved by the Invention) However, the planetary gear reducers shown in FIGS. 6 and 7 have the following problems.

In the case where the rotary shaft penetrates the hollow portion of the eccentric body shaft, if the shaft diameter of the rotary shaft is increased to increase the transmission torque, the inner diameter of the hollow portion must be increased. There is a limit in increasing the inner diameter of the hollow portion in terms of strength of individual parts of the.

Therefore, an object of the present invention is to provide a planetary gear reducer having three eccentric bodies integrally formed with a hollow eccentric body shaft, thereby increasing the transmission torque.

(Means for Solving the Problems) A feature of the present invention is that three eccentric bodies are integrally formed on a hollow eccentric body shaft, thereby reducing the thickness of the rollers and the inner peripheral ring. The inner diameter of the hollow part is increased.

However, in the eccentric body shown in FIG. 6, the number of eccentric bodies is up to two, and even if the three eccentric bodies shown in FIG. It is impossible to apply the body axis to a planetary gear reducer. The reason is that when three eccentric bodies are formed, each eccentric body is formed so as to be shifted by 120 degrees on the eccentric body axis, so that the inner ring of the roller should be inserted beyond these eccentric bodies. Is impossible.

Therefore, in carrying out the present invention, as shown in FIG. 9, three eccentric bodies 3D ₁ , which are integrally formed with the eccentric body shaft 3,
Of 3D ₂ and 3D ₃ , the eccentric body 3D ₃ at the end is attached to the small circle portion 3S.
And consist of a spacer ring 3R provided on its outer periphery, of the outer peripheral contour of the eccentrics 3D ₂ that the outer peripheral contour of the small circular portion 3S is adjacent smaller is formed so as inwardly, whereby the intermediate eccentric Roller 6 and inner ring 6 on 3D ₂
A can be inserted.

In carrying out the present invention, in addition to the configuration shown in FIG. 9, the eccentric body 3E ₃ at the end is a small circle as shown in FIG. 10, and the spacer ring 3S shown in FIG. a structure may be employed to provide the inner peripheral ring 3R ₃ of the total thickness of the inner circumferential ring 3R.

(Example) Hereinafter, one example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention.

In the following description, the same parts as those of the conventionally known structure shown in FIGS. 3 and 4 are designated by the same reference numerals.

On the eccentric body shaft 41, three eccentric bodies 3 ₁ ,
3 ₂ and 3 ₃ are integrally formed. Eccentric body 3 ₁ , 3
₂ and 3 ₃ are provided with rollers 6 ₁ , 6 ₂ and 6 ₃ ,
The rollers 6 ₁ , 6 ₂ , 6 ₃ are the inner peripheral rings 6A ₁ , 6A ₂ ,
It has 6A ₃ . The eccentric bodies 3 ₁ , 3 ₂ , 3 ₃ have inner rings 6A ₁ , 6A ₂ , 6A ₃ , and rollers 6 ₁ , respectively.
6 _2, 6 ₃ three external gear 5 through is fitted. The external gear 5 has external teeth 7 having a trochoidal tooth profile on its outer circumference. The internal gear 8 is formed integrally with the Kaesinge. Further, the internal gear 8 has an arcuate tooth shape composed of an external pin 9 that is internally meshed with the external gear 5. The outer pin 9 may have a structure in which an outer roller is loosely fitted. An internal pin hole 10 is formed in the external gear 5, and an internal pin 11 is loosely fitted in the internal pin hole 10. An inner roller 12 is loosely fitted to the outer periphery of the inner pin 11, and one end of the inner pin 11 is tightly fitted to the inner pin holding flange 13. Here, the inner roller 12 can be omitted. The inner pin holding flange 13 is fixed to the fixed side (not shown).

The above structure is similar to that of a conventionally known planetary gear reducer, but in the present invention, a hollow portion 42 that penetrates the eccentric body shaft 41 is formed at the center of the eccentric body shaft 41. still,
As shown in FIG. 9, the eccentric body 3 ₃ is composed of the circular portion 3 ₃₁ and the spacer ring 3 ₃₂ so that the roller 6 ₂ and the inner peripheral ring 6 A ₂ can be inserted into the central eccentric body 3 ₂ . As explained.

Since the present invention is configured as described above, the roller 6 ₁ ,
The loads acting on the inner peripheral rings 6 ₂ , 6 ₃ and the inner peripheral rings 6A ₁ , 6A ₂ , 6A ₃ are reduced, and the rollers 6 ₁ , 6 ₂ , 6 ₃ and the inner peripheral rings 6A ₁ , 6A ₂ , 6A _{3 in} the radial direction. Since the thickness can be reduced, the inner diameter of the hollow portion 42 can be increased. Therefore, when it is used as a joint of the robot shown in FIG. 2 below, it becomes possible to penetrate a hollow portion and pass through a thick shaft, and it is possible to transmit a large torque.
A robot joint with high transmission torque can be obtained.

Referring to FIG. 2, the rotation of the motor M1 is controlled by a bevel gear 41 provided on an output shaft of the motor M1 and a bevel gear 43 provided on an eccentric body shaft 42 of the first planetary gear reducer. 1 is transmitted to the planetary gear reducer. In this first planetary gear reducer, since the internal gear 44 is fixed to the motor holding frame 45, the internal pin holding flange 46 is on the output side of the decelerated rotation. The inner pin holding flange 46 is rotatably supported by a bearing 48 between the inner pin holding flange 46 and the inner gear frame 43, and the inner pin holding flange 46 is connected to a robot arm 50 via a connecting frame 49. Therefore, the rotation of the inner pin holding flange 46 is the rotation around the axis O ₁ of the arm 50 of the robot. Here, the axis O ₁ is the rotation center of the first planetary gear reducer.

The rotation of the motor M2 is transmitted to the bevel gear 53 provided at one end of the penetrating shaft 52 via the bevel gear 51 provided on the output shaft of the motor M2. Although the through shaft 52 is a hollow shaft in the illustrated example, it may be a solid shaft. A bevel gear 54 is provided at the other end of the through shaft 52 and meshes with a bevel gear 56 provided on an eccentric body shaft 55 of the second planetary gear reducer. The through shaft 52 is the eccentric body shaft 42 of the first planetary gear reducer.
Is provided through the hollow part of the
It is rotatably supported by 7. Thus, the rotation of the motor M2 is given to the eccentric body shaft 55 of the second planetary gear reducer via the through shaft 52. The second planetary gear reducer is provided in the arm 50 of the robot, and since the internal gear 58 is fixed to the arm 50, the rotation of the eccentric body shaft 55 is the same as the deceleration rotation of the inner pin holding flange 59. Will be output. An operation end 60 of a robot arm 50 is fixed to the inner pin holding flange 59, and the operation end 60 is rotatably supported between the arm 50 and the arm 50 by a bearing 61. The rotation of the operation end 60 is the rotation around the axis O ₂ . Here, O ₂ is the rotation center of the second planetary gear reducer.

In this way, the operating end 60 of the robot is revolved around the axis O ₁ by the motor M1 and is rotated around the axis O ₂ by the motor M2 to perform a predetermined work.

In such a joint of the robot, it is desired to transmit torque as high as possible, but for that purpose, the larger the diameter of the penetrating shaft 52, the better. In other words, the larger the inner diameter of the hollow portion of the eccentric body shaft 42, the better. Therefore, if an eccentric body shaft provided with three eccentric bodies is used as in the present invention, such requirements can be met.

The present invention is not limited to the above embodiment.

For example, in the description of FIG. 1, it has been described that the internal gear 8 is rotated integrally with the casing and the inner pin holding flange 13 is fixed, but the inner pin holding flange 13 is rotated,
It is obvious from that point that the internal gear 8 is integrally fixed to the casing and the output is taken out from the internal pin holding flange 13 to be included in the present invention.

Furthermore, the present invention is not limited to the speed reducer but can be applied to the speed increaser.

(Effects of the Invention) The effects of the present invention configured as described above are as follows.

Since the three eccentric bodies are provided, the transmission load acting on each one is reduced. Therefore, it is possible to reduce the radial thickness of the roller and the inner peripheral ring, and the inner diameter of the hollow portion of the eccentric body shaft can be increased accordingly. Therefore, the utilization of the hollow portion is improved, and when it is applied to a joint of a robot, a compact robot joint with high transmission torque can be obtained.

Since the outer peripheral contour of the eccentric body at one end is inside the outer peripheral contour of the central eccentric body and the spacer ring or the inner peripheral ring with different thickness is provided over the entire circumference, it is suitable for mounting the central eccentric body bearing. Does not hinder.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG.
FIG. 3 is a sectional view showing an example of a robot joint using the planetary gear reducer of FIG. 3, FIG. 3 is a sectional view of a conventionally known planetary gear reducer using two divided eccentric bodies, and FIG. 4 is of FIG. AA sectional view, FIG. 5 is a sectional view of a conventionally known planetary gear reducer using an integrally formed eccentric body, and FIG. 6 is a sectional view showing a conventionally known planetary gear reducer using an eccentric body shaft, 7 is a sectional view showing a joint of a robot using the planetary gear reducer of FIG. 6, FIG. 8 is a sectional view of a conventionally known planetary gear reducer using three eccentric bodies, and FIG. 9 is FIG. 10 is a cross-sectional view of a planetary gear reducer that uses an eccentric body shaft that integrally includes three eccentric bodies, and FIG. 10 shows another planetary gear reducer that uses an eccentric body shaft that integrally includes three eccentric bodies. FIG. 3 ₁ , 3 ₂ , 3 ₃ : Eccentric body 3 ₃₁ : Circle part, 3 ₃₂ : Spacer ring 5: External gear, 6 ₁ , 6 ₂ , 6 ₃ : Roller 6A ₁ , 6A ₂ , 6A ₃ : Inner ring 8: Internal gear, 9: Outer pin, 10: Inner pin hole 11: Inner pin, 12: Inner roller 13: Inner pin holding flange, 41: Eccentric body shaft 42: Hollow part

Claims (2)

[Claims] 1. A hollow eccentric body shaft, three eccentric bodies integrally formed on the eccentric body shaft, and three external teeth fitted to the eccentric body via rollers and an inner peripheral ring. The three eccentricities, each of which is composed of a gear, an internal gear that internally meshes with the external gear, an internal pin that penetrates the external gear, and an internal pin holding flange that holds the internal pin. The outer ring contour of at least one of the eccentric bodies at both ends of the body is formed so as to be inside the outer contour of the middle eccentric body, and a spacer ring is formed on the one eccentric body so as to have a regular outer contour of the eccentric body. And the inner ring of the eccentric body bearing is fitted to the spacer ring. 2. A hollow eccentric body shaft, three eccentric bodies integrally formed on the eccentric body shaft, and three external teeth fitted to the eccentric body via rollers and an inner peripheral ring. The three eccentricities, each of which is composed of a gear, an internal gear that internally meshes with the external gear, an internal pin that penetrates the external gear, and an internal pin holding flange that holds the internal pin. The outer peripheral contour of at least one of the eccentric bodies at both ends of the body is formed so as to be inside the outer peripheral contour of the middle eccentric body, and the outer peripheral contour of the one eccentric body is a regular outer peripheral contour. A planetary gear reducer, characterized in that an eccentric body bearing having an inner ring having a different thickness over the circumference is fitted.