JPS5899549A - Differential planet rotary type reduction gear - Google Patents

Abstract

PURPOSE:To provide a compact reduction gear with infinitely variable reduction ratio by mounting a pair of reduction gears respectively provided planet rotary mechanisms and having different reduction ratios on different diameter portions of a same stepped rotary input shaft to utilize the difference between the diameters of the shaft. CONSTITUTION:An input shaft 1 is a stepped one provided with different diameter portions 1A, 1B and journalled by a support 3 provided with a bearing 5. A plurality of bearings 9 are arranged in equal intervals on said larger diameter portion 1A and respectively fitted on a plurality of pins 7 planted on the support 3, while an annular body 11 coaxial with the shaft 1 is arranged around the outer periphery of the bearings 9. Also, a plurality of bearings 13 similar to the bearings 9 are arranged to make rolling contact with the smaller diameter portion 1B. Then, the dameter r5 of the bearing 13 is larger than the diameter r3 of the bearing 9 and the bearings 13 contact closely the annular body 11. Thus, the large and small diameter portions 1A, 1B can be respectively formed with first and second planet rotary type reduction gear mechanisms 10, 20.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention is applicable to planetary rotation type differential speed reducers, especially devices such as eN robots and arms that need to obtain large torque with a small drive unit. Applicably, 1) relates to a suitable speed reduction mechanism.

12) Background of the Technology For example, in driving a robot arm, an actuator that can provide high output at a relatively low speed (low rotational speed) of at most several rps is generally required. Therefore, an electric motor is generally used as a drive source for the 1.5-inch arm, but in that case, a gear train reducer, a worm gear reducer, or a harmonic drive reducer is used to obtain high output.

t31 Prior Art and Problems However, all of these conventional speed reducers have the problem that a large speed reduction ratio cannot be obtained because the speed reduction ratio is determined by the tooth number ratio. In addition, in order to obtain a large reduction ratio, the number of gears must be increased, and the entire speed reduction gear becomes a dog-like shape. It was practically impossible.

(4) Purpose of the Invention The purpose of the present invention is to provide a small and simple speed reduction device that can obtain a virtually infinite speed reduction ratio. It is in.

15) Structure of the Invention In order to achieve the above-mentioned object, according to the present invention, a pair of reducers each having a planetary rotation mechanism and having different reduction ratios are all attached to different diameter portions of the same stepped rotation input shaft. A differential speed reduction device is provided in which a large speed reduction ratio is obtained by a diameter difference between different diameter portions.

16) Examples of the invention Embodiments of the present invention will be described below with reference to the drawings.

The input shaft 1 is a stepped shaft having different diameter portions IA and IB. The diameter and radius of one large diameter section are respectively D1. r1 and small diameter part 1
The IK diameter and radius of B are respectively D2. Let it be r2. Input shaft 1
is rotatably supported by a retainer 3 having a bearing 5. For example, three bearings 9 are arranged on one large diameter portion of the shaft 1 at intervals of 120°. Axle pins 7 extending parallel to the shaft 1 are protruded from the retainer B at 120° intervals, and bearings 9 corresponding to these axle pins 7 are rotatably fitted. An annular body 11 is disposed on the outer periphery of the bearing 9 coaxially with the shaft 1. Therefore, the large diameter part IA of the 9-shaft bearing! : The rollers come into contact with the IJ body 11. Pottery,
A radial pressurizing force is applied from the outer periphery of the ring body 11 via a known wedge type pressurizing mechanism, for example, to the bearing 9,
It is preferable to increase the closeness between the ring body 11 and the shaft 1.

On the other hand, three bearings 13 are also brought into rolling contact with the small diameter portion 1B of the river 11, similar to the bearing 9. The diameter r5 of the bearing 13 is the diameter r3 of the bearing 9.
((rs>rs), bearing 13 is also thicker than ring body 1
It is arranged to be in close contact with the inner circumference of 1. Output rotating body 15
is rotatably supported on the shaft 1 via a bearing 19,
It has three shaft pins 17 similar to the shaft pins 7 of the retainer 3. These shaft pins 17 are arranged at intervals of j7j4120°, and bearings 13 corresponding to these shaft pins 17 are rotatably fitted.

Thus, a first planetary rotary speed reduction mechanism is formed in the large diameter portion 1B of the shaft 1, and a second planetary rotation speed reduction mechanism is formed in the small diameter portion 1B of the shaft 1. In the first planetary rotary reduction mechanism, the large diameter portion of the shaft 1 corresponds to the sun rotor, and the bearing 9 corresponds to the planetary rotor, and in the second planetary rotation reduction mechanism, the small diameter portion IB-Af of the shaft 1 corresponds to the sun rotor. The sun rotor and the bearing 13 each correspond to a play barrel rotor.

Now, in the above-mentioned P-hole planetary rotation mechanism, if the cage 3 is assumed to be fixed, the rotation angle θ1 of the input @1 and the rotation angle θ4 of the ring body 11 are calculated by the following equation as well-known assuming that there is no relative slip. be satisfied.

1 θ4=--θ1...Book 1 fist・(1) 4 However, ra = inner radius of the ring body 11 Next, if the ring body 11 is considered fixed, similarly, the rotation angle θ1 of the input shaft 1 and , and the rotation angle 06' of the output rotating body 15 that supports the bearing 13 have the following relationship.

ra+? 2. Also, when the input shaft 1 is fixed and the ring body 11 is rotated by θ4 in equation (1), the rotation angle θ6 of the output rotating body 15 is:
Using equation (1), ra + r2 Therefore, the final rotation angle θ6 of the output rotating body 15 is 0
6' and θ6", and is expressed as r4+r2 γ4+r2. From this, the reduction ratio becomes r2 - 9'1.

Therefore, if rl>τ2, the rotational direction of each rotating body is the first
It will look like the arrow in the figure.

As is clear from Equation (4), if <ra is constant, the reduction ratio is determined by the magnitude of T2-τ1, that is, the difference between the small diameter section 1B and the large diameter section 1 of the shaft 1. By appropriately selecting the dimensions of the large diameter portion, the reduction ratio can be freely changed.

Since K increases as r2−rl becomes smaller, τ2
Theoretically, K can be made infinite by reducing the difference between and rl without visual acuity. When ri=2=ri, the rotations of the ring body 11 and the shaft 1 are completely offset, so the bearing 13 simply idles at the same position and the output rotating body 15 does not rotate.

In the above description, outer teeth are formed on the large diameter portion 1A and small diameter portion 1B of the shaft 1, inner teeth are formed on the ring body 11, and the bearings 9 and 13 are arranged as shifted gears that mesh with these inner and outer teeth. Of course, it is also possible to create a complete planetary gear mechanism by doing so. However, in the case of gears, a rolling contact type as shown in the illustrated embodiment is preferable since it involves balaclarity.

However, in the illustrated embodiment, the diameter r of the planetary bearings 9, 13
3. The diameters of the planetary bearings 9' and 15' are made the same and the diameters of the planetary bearings 9' and 15' are made the same as shown in FIG. It will be understood that exactly the same effect can be obtained if the ring body 11' has a stepped inner diameter. In this case, the reduction ratio becomes t' 2 - rl 4 . In addition to the large diameter part 1B and the small diameter part 1B of the input shaft 10, the input shaft 1 is also provided with stepped parts for the purpose of stopping the axial blank areas of each rotor. , small diameter section 1B
The stepped portions other than the above are completely unrelated to the function of the reduction gear of the present invention.

(7) Effects of the Invention As described above, according to the present invention, the differential type planetary rotation having a simple structure allows the reduction ratio to be virtually infinitely increased by reducing the diameter difference between the different diameter portions of the useful shaft portion. A type speed reduction device is obtained.

[Brief explanation of drawings]

FIG. 1 is an exploded illusion diagram of a speed reduction device according to the present invention, FIG. 2 is an axial front view of a first planetary rotary reducer section, and FIG. 3 is an axial direction view of a second planetary rotary speed reducer section. FIG. 4 is a front view, FIG. 4 is a developed cross-sectional view of the reduction gear device of the present invention, and FIG. 5 is a main part diagram showing another embodiment of the present invention. 1...Input shaft, 1 person...Large diameter section, 1B...
...Small diameter part, 3...Cage, 9.13...e
II planetary bearing, 10...first planetary rotary reduction mechanism, 11...ring body, 15...output rotating body, 20...second planetary gear reduction mechanism. Patent applicant Fujitsu Ltd. Patent application representative Patent attorney Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney Yukio Uchida Patent attorney Akira Yamaguchi

Claims (1)

[Claims] A planetary rotary speed reduction mechanism for ¥1 consisting of a ring body coaxially arranged around the large diameter part (or small diameter part) of a stepped human-powered shaft having different diameter parts so as to be freely rotatable via a first planetary rotor. and an output rotating body via a second planetary rotor disposed around the small diameter part (or large diameter part) of the input shaft between the small diameter part (or large diameter part) of the input shaft and the ring body. and a second planetary rotary speed reducer groove rotatably supported by the shaft, and by making the reduction ratios of the area speed mechanisms different, the rotation of the input shaft is reduced and transmitted to the output rotating body. This is a planetary rotary type reduction gear that is characterized by being K-shaped to make it possible to do so.