JPH07332448A - Reduction gear - Google Patents

Abstract

PURPOSE:To perform free design of a ring diameter and the outside diameter of a planetary wheel without needing special processing applied on constituting parts by a method wherein one of planetary wheels is rotated along the inner peripheral surface of a first ring and the other part of the planetary wheels is rotated along the inner peripheral surface of a second ring. CONSTITUTION:When a bracket 12 on the input side is rotated through rotation of an input shaft 11, the roller parts 15 and 18 of planetary wheels 7 and 8 are revolved as they are rotated along the guide surface of a fixed ring 5 and the roller parts 16 and 19 of the planetary wheels 7 and 8 are revolved as the roller parts are rotated integrally with the roller parts 15 and 18, respectively. Since a rotary ring 6 brought into contact with the roller parts 16 and 19 of the planetary wheels 7 and 8 is rotated, a decelerated output is fetched from an output shaft 22. Since, as noted above, a deceleration device 1 employs structure using the planetary wheels 7 and 8 which are revolved as the planetary wheels are rotated along the fixed ring 5 and the rotary ring 6, there is no need for special processing on a constitution part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has made it possible to simplify the structure and reduce the cost by using a reduction mechanism using a ring and a planet wheel that revolves along its inner peripheral surface. It is intended to provide a new speed reducer.

[0002]

2. Description of the Related Art For example, what is called a harmonic speed reducer is known as a speed reducer used when it is desired to obtain a high torque at a low speed such as when driving a robot arm.

This harmonic speed reducer is a compact speed reducer capable of obtaining a reduction ratio of 1 to 1/100 which is several tens of minutes in one stage.

[0004]

However, the harmonic speed reducer requires parts that require special precision processing (such as flexspline belts and elliptical bearings), which makes it expensive in terms of price and increases costs. However, there is a problem that it is difficult to freely design the size and shape due to its structure.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an input side bracket fixed to an input shaft, a first ring fixed in a housing, and a rotary shaft thereof. The first ring should be aligned with the central axis of the first ring.
A second ring rotatably arranged with respect to the ring, a plurality of shafts arranged on the input side bracket at substantially equal angular intervals on the circumference centered on the rotation axis of the input shaft, and the shafts respectively. A plurality of planet wheels rotatably mounted and an output side bracket fixed to the second ring and the output shaft are provided, and a part of each planet wheel rotates along the inner peripheral surface of the first ring. The other part of the planetary wheel is rotated along the inner peripheral surface of the second ring.

[0006]

According to the present invention, the planetary wheel provided on the input side bracket revolves along the inner peripheral surfaces of the first and second rings, so that the deceleration output from the second ring via the output side bracket is achieved. Therefore, the ring diameter, the outer diameter of the planetary wheel, etc. can be freely designed without requiring special processing for these components.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The speed reducer of the present invention will be described below with reference to the illustrated embodiments.

1 to 4 show a first embodiment of the present invention.

Reference numeral 1 denotes a speed reducer, which has a metal housing 2.

The housing 2 is formed by joining two cylindrical housing halves 2a and 2b, and a reduction portion 4 is provided in a hollow portion 3 thereof. In the following description, it is assumed that an input shaft described later is inserted into the housing half 2a and an output shaft described below is inserted into the housing half 2b, and the side provided with the housing half 2a is the front side. The side on which the body half 2b is provided is referred to as the rear side.

The deceleration portion 4 has two rings 5 and 6 and planet wheels 7 and 8 that revolve along the inner peripheral surfaces of these rings.

The ring 5 is a fixed ring and is press-fitted and fixed in a state in which a portion near the outer peripheral edge thereof is received in a step portion 9 formed on the rear end surface of the housing half 2a. still,
The fixing ring 5 is made of metal or synthetic resin.

The ring 6 is a rotating ring, and is rotatably provided with respect to the fixed ring 5 while being in contact with the retainer 10. The rotating ring 6 is made of metal, synthetic resin or the like, and its outer diameter and inner diameter are slightly larger than those of the fixed ring 5. The retainer 10 is formed in a ring shape using a material having a small friction coefficient such as Teflon, and is fixed to the fixing ring 5 by being fitted onto the outer peripheral edge portion of the fixing ring 5.

As shown in FIGS. 2 and 3, on the inner peripheral surfaces of the fixed ring 5 and the rotary ring 6, a belt-shaped member formed of a material having a high friction coefficient such as a rubber material is provided over the entire circumference. Affixed to the guide parts 5a, 6
a are formed respectively. Instead of providing the friction member on the inner peripheral surface of the ring as described above, the inner peripheral surface may be subjected to friction surface processing such as knurling.

Reference numeral 11 denotes an input shaft, the end of which is fixed to the input side bracket 12.

The input side bracket 12 is made of metal, and two shafts 13 and 14 extending rearward are fixed to the input side bracket 12. Both of the shafts 13 and 14 are made of metal and are symmetrical with respect to the input shaft 11, that is, the input shaft 11
Are arranged with an angular interval of 180 ° around the axis. Regarding the number of shafts to be arranged, as shown by phantom lines in FIG. 3, generally, the number of shafts is n (≧ 2), and the shafts may be arranged around the input shaft 11 at an angular interval of 360 ° / n. it can.

The planet wheel 7 is rotatably mounted on the shaft 13, and the planet wheel 8 is rotatably mounted on the shaft 14.

Each of the planet wheels 7 and 8 is made of metal, and two guided surfaces that are guided along the fixed ring 5 and the rotating ring 6 are formed on the outer peripheral surface of each planet wheel. .

The planet wheel 7 includes a roller portion 15 and a roller portion 1.
6, the roller portion 15 near the input side bracket 12 has a smaller outer diameter than the roller portion 16. Then, the outer peripheral surface 15a of the roller portion 15 is guided while being in contact with the guide portion 5a of the fixed ring 5,
Further, the outer peripheral surface 16a of the roller portion 16 is guided while being in contact with the guide portion 6a of the rotating ring 6. still,
Bearings 17, 17 are provided inside the planetary wheel 7. In other words, the planet wheel 7 has these bearings 17, 1
Is rotatably supported on the shaft 14 via 7,
In the planetary wheel 7, the roller portions 16 and 17 have a shaft 14
It is designed to be rotated integrally around the.

The planet wheel 8 has the same structure as that of the planet wheel 7 and comprises a roller portion 18 and a roller portion 19, and the roller portion 18 near the input side bracket 12 has an outer diameter larger than that of the roller portion 19. Has been made smaller. And
The outer peripheral surface 18a of the roller portion 18 is guided in a state of being in contact with the guide portion 5a of the fixed ring 5, and the outer peripheral surface 19a of the roller portion 19 is in contact with the guide portion 6a of the rotating ring 6. Will be guided in. Two bearings 20, 20 are provided inside the planetary wheel 8, and the planetary wheel 8 is rotatably supported by a metal shaft 14 via the bearings 20, 20. The vehicle 7 has its roller portions 18 and 19 integrally rotated around the shaft 14.

Reference numeral 21 is an output side bracket, and a portion of the front end portion near the outer peripheral edge is fitted and fixed to the rotating ring 6 and an output shaft 22 is fixed to the central portion thereof.

Reference numeral 23 is a bearing, which is received by a step 24 formed near the rear end of the inner peripheral surface of the housing half 2b on the output side, and is formed on the step 24 and the rear end of the output side bracket 21. Step 21 for holding the bearing
It is held between a and.

The input shaft 11, the output shaft 22, the fixed ring 5, and the rotating ring 6 are arranged so that their central axes are all coaxial with each other, and the rotational force of the input shaft 11 is transmitted via the planet wheels 7 and 8. It is decelerated by being transmitted to the rotary ring 6, the output side bracket 21 and the output shaft 22 connected to the rotary ring 6. That is, when the input side bracket 12 is rotated by the rotation of the input shaft 11, the roller portion 1 of the planet wheels 7 and 8 is rotated.
5, 18 revolve around the guide surface of the fixed ring 5 while revolving, and the roller portions 16, 1 of the planet wheels 7, 8
9 revolves around the rollers 15 and 18 while rotating integrally with the rollers 15 and 18, whereby the roller 1 of the planet wheels 7 and 8 is rotated.
Since the rotating ring 6 that is in contact with the rotating shafts 6 and 19 is rotated, the output that has been decelerated is taken out from the output shaft 22. The speed reduction ratio in this case is defined by the outer diameter of the roller portion of the planetary vehicle and the like.

As described above, the speed reducer 1 employs the structure using the planet wheels 7 and 8 that revolve around the fixed ring 5 and the rotary ring 6 while rotating on its own axis. There is an advantage that no processing is required and the number of parts is relatively small.

In this embodiment, the planet wheels 7 and 8 are supported on the shafts 13 and 14 by using the bearings 17 and 20, respectively. However, a metal bearing (oil-containing) or a hard and smooth material (for example, acetal resin) is used. A sleeve formed of (POM) or the like may be used.

Next, a speed reducer 1A according to a second embodiment of the present invention will be described with reference to FIGS.

The second embodiment is different from the first embodiment in that the engagement structure between the inner teeth of the ring member and the planetary gear is used, and in many parts. Since it is similar to the first embodiment, the same parts are designated by the same reference numerals as the same parts in the first embodiment, and the description thereof is omitted.

The fixed ring 5A and the rotary ring 6A may be formed as an internal gear by forming an involute tooth profile on the inner peripheral surfaces thereof, but there is a problem in terms of noise and backlash. Timing belts 25 and 26 are attached over the entire circumference. For example, as shown in FIG. 6, grooves 27 and 28 are formed on the inner peripheral surfaces of the fixed ring 5A and the rotating ring 6A, respectively, and timing belts 25 and 26 formed of an elastic material are formed on these grooves 27 and 28, respectively. It can be fitted and glued.

A timing pulley corresponding to the tooth shape and pitch of the timing belt 25 is used for the planetary gears 7A and 8A.

That is, the planetary gear 7A comprises a tooth portion 15A and a tooth portion 16A, and the tooth portion 15A near the input side bracket 12 has a smaller diameter than the tooth portion 16A. The tooth portion 15A is the timing belt 25 of the fixed ring 5.
And the tooth portion 16A meshes with the timing belt 26 of the rotary ring 6.

In the planetary gear 8A, as in the planetary gear 7A, the tooth portion 18A near the input side bracket 12 has a tooth portion 19A.
The diameter is smaller than A. The tooth portion 18A is meshed with the timing belt 25 of the fixed ring 5, and
The tooth portion 19A meshes with the timing belt 26 of the rotating ring 6.

Therefore, in the speed reducer 1A, the input shaft 1
When 1 rotates, the tooth portions 15A of the planetary gears 7A, 8A, 1
8A meshes with the timing belt 25 of the fixed ring 5A and revolves while rotating, and the planetary gears 7A,
Since the tooth portions 16A and 19A of 8A revolve with the tooth portions 15A and 18A while rotating respectively, the rotary ring 6A meshed with the tooth portions 16A and 19A of the planetary gears 7A and 8A is rotated. The rotating force is decelerated and output to the rotating ring 6A.

In this case, the reduction ratio is the tooth number ratio of the tooth portions 15A and 16A of the planetary gear 7A and the tooth portion 1 of the planetary gear 8A.
It is determined by the tooth number ratio of 8A and 19A. Although details of the method of calculating the reduction gear ratio are omitted, the relationship (the difference in the number of teeth of the teeth is a multiple of 2) derived due to the fact that the number of planetary gears is 2 is taken into consideration. It is possible to obtain a reduction ratio of about 1/20 to 1/80 by setting the number of teeth.

In the second embodiment, the timing belts 25 and 26 are attached to the inner peripheral surface of the ring and the planetary gears 7A and 8A corresponding to the timing pulleys are used to solve the backlash problem. Since the timing belts 25 and 26 are made of a material having a high elasticity, the deceleration can be performed quietly and smoothly. When the speed reducer 1A operates, almost no tension is applied to the timing belt itself, and the pressing force from the planetary gears to the timing belt is received by the ring, so that durability and load capacity can be improved.

[0035]

As is clear from the above description, according to the first aspect of the invention, the planetary wheel provided on the input side bracket includes the first ring fixed to the housing and the first ring. By revolving along the inner peripheral surface of the second ring, which is rotatably arranged around the rotation axis that is substantially coaxial with the center axis of the ring, the second ring passes through the output side bracket. The deceleration output can be obtained. Therefore, the structure is relatively simple, and no special processing is required for the component parts, so that the cost can be reduced.
Further, since the ring diameter, the outer diameter of the planetary wheel, and the like can be appropriately designed, the degree of freedom in design is high.

According to the second aspect of the present invention, the inner peripheral surfaces of the first and second rings are subjected to friction surface processing or a friction member is provided to form a friction surface, and the ring and the planetary wheel are connected to each other. The mechanism can be simplified by utilizing the friction.

According to the third aspect of the invention, the backlash is eliminated by providing the timing belt over the entire inner peripheral surface of the first and second rings and using the planet wheel as the timing pulley. Deceleration with low noise can be performed.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a first embodiment of the present invention.

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

3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a perspective view showing an input shaft, an input side bracket, and a planetary wheel.

FIG. 5 is a sectional view showing a main part of a second embodiment of the present invention.

FIG. 6 is an enlarged cross-sectional view showing a stuck state of a timing belt on a fixed ring or a rotating ring.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reduction gear 2 Housing 5 Fixed ring (1st ring) 5a, 6a Guide part (friction member) 6 Rotation ring (2nd ring) 7, 8 Planetary wheel 12 Input side bracket 13, 14 Shaft 21 Output side bracket 1A Reduction gear 7A Planetary gear (planetary wheel) 8A Planetary gear (planetary wheel) 15A, 16A, 18A, 19A Teeth 25, 26 Timing belt

Claims (3)

[Claims] 1. An input-side bracket fixed to an input shaft, a first ring fixed in a housing, and a first ring fixed to the first ring so that its rotation axis substantially coincides with the central axis of the first ring. A second ring rotatably arranged with respect to the shaft, a plurality of shafts arranged on the input side bracket at substantially equal angular intervals on the circumference centered on the rotation axis of the input shaft, and rotatably on the respective shafts. A plurality of mounted planetary wheels and an output side bracket fixed to the second ring and the output shaft are provided, and a part of each planetary wheel is rotated along the inner peripheral surface of the first ring. A speed reducer characterized in that the other part of the planetary wheel is rotated along the inner peripheral surface of the second ring. 2. The speed reducer according to claim 1, wherein the inner peripheral surfaces of the first and second rings are subjected to friction surface processing or a friction member is provided to form a friction surface, and the friction surface is a planetary surface. The planetary wheels are the first and the second while being in contact with the outer peripheral surface of the vehicle.
A speed reducer characterized by being rotated along the inner peripheral surface of the ring. 3. The speed reducer according to claim 1, wherein a timing belt is attached over the entire circumference of the inner peripheral surfaces of the first and second rings to form teeth, and each planet wheel corresponds to the timing belt. So that the planet wheels are rotated along the inner peripheral surfaces of the first and second rings with the teeth of the first and second rings and the teeth of the planet wheel meshing with each other. The speed reducer characterized in that