JPH0642128Y2 - Reduction mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a reduction mechanism having a large reduction ratio.

B. Outline of the Invention In the present invention, the rotational force of the input shaft is transmitted to the chain via the cam, and the chain meshes with the stationary star wheel and the rotating star wheel at the contact points on the circumference. The rotation-side star wheel is rotated by sequentially moving on the circumference according to the rotation of the cam, and this reduction-speed mechanism uses the rotation-side star wheel as an output shaft. Further, the same reduction mechanism having the output shaft as the input shaft is combined in multiple stages to increase the reduction ratio.

C. Prior Art In recent years, as represented by robot arm drive, a relatively small high-speed motor is often used with a reduction mechanism having a large reduction ratio.

This kind of reduction gear mechanism is replaced with a reduction gear mechanism by a combination of gears. For example, as shown in FIG. 5, a rigid internal gear 1 and an internal gear 1 are arranged inside the internal gear 1 and teeth of the internal gear 1 are arranged. An inner surface of the external gear 2 via an elastically deformable cylindrical external gear 2 having a smaller number of teeth and a ball bearing 3 arranged inside the external gear 2. The one provided with an elliptical cam 4 that slides on the inside is used.
Then, for example, when the cam 4 is rotated while the internal gear 1 is fixed, the external gear 2 is elastically deformed as the cam 4 rotates, and the external gear 2 and the internal gear 1 are separated from each other. Move the meshing position of (the long axis end of the ellipse) sequentially in the circumferential direction,
The external gear 2 is rotated according to the difference in the number of teeth between the internal gear 1 and the external gear 2, and the decelerated output is taken out.

D. Problems to be Solved by the Invention Conventionally, this type of reduction gear mechanism uses the principle of a differential gear, but the drawback of this type of reduction gear mechanism is that a large reduction ratio can be obtained. Since the tooth profile of the gear is a triangular gear without using an impoliute tooth profile, the mechanical efficiency is about 50%. Also, since the external gear repeats elastic deformation, there is a problem in terms of life and durability, and reliability is poor. . Further, since the external gear continuously elastically deforms, it is equivalent to that it is via a torsion spring when viewed from the load side, which results in a low-frequency torsional vibration in the reduction gear system, especially in the robot. There was a problem that it was unfavorable for the control of the arm and the like. In addition to this, there is a speed reduction mechanism using a trocodile gear, but it requires the use of specially processed parts, which complicates the assembly work and causes a cost increase.

E. Means for Solving the Problems The present invention solves the above problems and provides a speed reduction mechanism that can achieve stable and highly efficient speed reduction. That is, the rotational force of the input shaft is transmitted to the chain via the cam, and the chain meshes with the stationary star wheel and the rotating star wheel at one point on the circumference, and this meshing position is sequentially circled as the cam rotates. The rotation-side star wheel is rotated by moving the rotation-side star wheel, and the rotation-side star wheel serves as an output shaft to form a speed reduction mechanism.

F. Action In the present invention, the rotational force of the input shaft is transmitted to the chain via the cam, and the chain meshes with the teeth of the stationary star wheel and the rotating star wheel at the contact points on the circumference.
This meshing position is such that it sequentially moves on the circumference according to the rotation of the cam and is decelerated due to the difference in the number of teeth of the two star wheels.

G. Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment in which the speed reducing mechanism of the present invention is used in two stages, and FIG. 2 is a sectional view showing an AA section of FIG.
Note that, in FIG. 2, the rib portion of the cam 19 is omitted. 1 and 2, 5 is a case,
Reference numeral 6 is a cover of the case 5, 7 is an input shaft (input shaft to the first stage reduction mechanism), 8 is an output shaft of the first stage reduction mechanism, which serves as a second stage input shaft. 9 is an output shaft (second stage output shaft), 10 is a bearing that supports the input shaft 7 on the case 5, 11 is a bearing that supports the output shaft 9 on the cover 6, and 12 is provided on the input shaft 7. Arc-shaped cam, 13 is a double chain (first stage),
14 is a fixed side star wheel (first stage), 15 is a rotating side star wheel (first stage), 16 is a fixed side star wheel (second stage), 17 is a fixed star wheel 16 fixed to the case 5. For supporting the intermediate stage, 18 is a bearing for pivotally supporting the second stage input shaft 8 on the intermediate case 17, and 19 is the second stage input shaft 8.
Cam provided on the, 20 is a double chain (second stage), 21
Is a rotating side star wheel (second stage). 20a is a pin of the chain and 20b is a roller of the chain.

As shown in FIG. 1, the cams 12 and 19 are concentrically rotated by the input shaft 7 and have an arc portion which is partially joined to the chain 13. Although it becomes a balanced load, the unbalanced load can be reduced by the wall thickness of the cam and the shapes of the ribs 22 and 23, 23 as shown in FIG. 3, and as shown in FIG. Since the unbalanced load can be prevented by setting the meshing points of the rotating star wheel at a plurality of points, for example, three points, the torsional vibration of the input shaft can also be significantly reduced.

Next, the operation will be described. First, in the first-stage speed reduction mechanism, the rotation input is transmitted from the input shaft 7 to the cam 12, and is transmitted to the chain 13 that is joined to the cam 12.
Is engaged with the tooth profile of the fixed side star wheel 14 and the rotating side star wheel 15 at one point on the circumference, so this engagement position moves sequentially on the circumference according to the rotation of the cam 12, and the chain
The movement of 13 causes the rotation-side star wheel 15 to rotate.
The rotation of the rotating star wheel 15 is the rotation of the output shaft 8. Next, the output shaft 8 is the input shaft of the second stage reduction mechanism, and the rotational force of the input shaft 8 is transmitted to the cam 19 and the chain 20 joined to the cam 19, and the chain 20
Has meshed with the tooth profile of the fixed side star wheel 16 and the rotating side star wheel 21 at one point on the circumference, so this meshing position moves sequentially on the circumference according to the rotation of the cam 19, and the chain 19 moves. Therefore, the rotating star wheel 21 rotates. The rotation of the rotating star wheel 21 is the rotation of the output shaft 9 and is taken out as a decelerated output.

Next, the relationship between the fixed and rotating star wheel teeth for deceleration will be described. For example, the first of the present embodiment
In the stepped reduction mechanism, the number of teeth on the fixed side star wheel = 20, pitch circle = 40.59mmφ, outer diameter = 43.5mmφ, the number of teeth on the rotating side starwheel = 21, pitch circle = 42.61mmφ, outer diameter = 45.5mmφ When the pitch of the chain 13 is 6.35 mm, the roller diameter is 3.3 mmφ, and the pin diameter is 2.31 mmφ, the reduction ratio of the first reduction gear mechanism is Is obtained.

Further, the reduction ratio of the second reduction mechanism is as follows: fixed side star wheel 16 teeth = 15 teeth pitch circle = 45.81mmφ, outer diameter = 51mmφ rotating side star wheel 21 teeth = 16 teeth pitch circle = 48.82mmφ, If the outer diameter is 53 mmφ and the chain 20 has a pitch of 95.25 mm, a roller diameter of 5.08 mmφ, and a pin diameter of 3.59 mmφ, the speed reduction ratio of the second speed reduction mechanism is Is obtained.

Therefore, the rotation speed of the input shaft 7 in the first reduction mechanism is 1/21.
The speed is reduced to 1/16 and further reduced to 1/16 by the second stage reduction mechanism. Therefore, the output shaft 9 (integral structure with the rotating star wheel 21) is 16 × 21 = 336, that is, the rotation of the input shaft 7 can be decelerated to 1/336 in the output shaft 9.

In the present embodiment, the case where the reduction gear mechanism is used in two stages is shown.
A one-step or three-step or more speed reduction mechanism may be used. In addition, I explained the case where two chains are used as the chains 13 and 20, and the two chains are meshed with the star wheel with two different numbers of teeth. However, a series of chains has two different numbers of teeth. The star wheel may be meshed.

H. Effect of the Invention As described above, the speed reduction mechanism of the present invention transmits the rotational force of the input shaft to the chain via the cam, and the chain has a fixed side star wheel and a rotating side star wheel with different numbers of teeth. Since the speed reducing mechanism uses the rotating star wheel as the output shaft by meshing at one point on the circumference and moving this meshing position sequentially on the circumference according to the rotation of the cam, (1) conventional deceleration Since a large reduction ratio can be obtained without interposing an elastic body such as an externally toothed gear that elastically deforms like a mechanism, there is no risk of low-frequency torsional vibration, the purpose of deceleration is achieved, and control is achieved. Good sex.

(2) An output shaft can be obtained concentrically with the input shaft, and if a mechanism of the same principle is added, a larger reduction ratio can be obtained.

(3) It is efficient because of the relationship between the chain and the star wheel.

And the like.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view showing an AA section of FIG. 1, and FIGS. 3 and 4 are plan views showing an embodiment of a cam of the present invention. , FIG. 5 is a sectional view showing a conventional reduction gear mechanism. 7 ... Input shaft, 8 ... First stage output shaft (second stage input shaft), 9 ... Output shaft, 12 ... Cam, 13 ... Chain (first stage), 14 ... Fixed Side star wheel (first stage),
15 …… Rotating side star wheel (first stage) 16 …… Fixed side star wheel (second stage), 19 …… Cam, 20 …… Chain (second stage), 21 …… Rotating side star wheel (Second
Step).

Claims (1)

[Scope of utility model registration request] 1. Two star wheels having different numbers of teeth are concentrically confronted, one of them is fixed, the other is rotatably supported, and meshes with the teeth of the fixed and movable star wheels. A chain that meshes with its tooth profile at at least one point on the circumference is provided, and a cam that has an arc portion that is rotated by the input shaft and that is partially joined to the chain and that rotates around the input shaft is provided inside the chain, The rotation of the input shaft rotates the arc portion of the cam to move the position where the fixed side and the tooth profile of the rotating star wheel mesh with each other on the circumference, thereby rotating the rotating star wheel through the chain. A reduction mechanism characterized in that rotation is output to an output shaft provided on a star wheel.