JP4570737B2 - Traction drive reducer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a traction drive speed reducer comprising a circumscribed shaft, a plurality of intermediate shafts arranged in contact with the outer periphery of the circumscribed shaft, and an inscribed cylinder inscribed in the outer periphery of the intermediate shaft.
[0002]
[Prior art]
In such a traction drive speed reducer comprising a circumscribed shaft, a plurality of intermediate shafts arranged in contact with the outer periphery of the circumscribed shaft, and an inscribed cylinder inscribed on the outer periphery of the intermediate shaft, the circumscribed shaft is rotated by a drive motor or the like. A traction drive speed reducer is known in which an intermediate shaft is rotatably supported on a support and an output is taken out from the support (for example, Japanese Patent Laid-Open No. 58-119746).
[0003]
[Problems to be solved by the invention]
However, in a conventionally known traction drive speed reducer, if there are variations in the diameters of a plurality of intermediate shafts, the center of rotation of the support for taking out the output cannot coincide with the center of the circumscribed shaft. For this reason, there exists a malfunction that rotation nonuniformity arises in the output taken out from the support body.
[0004]
That is, in the conventional traction drive speed reducer, the rotational force from the drive motor is input to the circumscribed shaft, and the output is taken out from the support body that supports the intermediate shaft. In this case, if the center of the inscribed cylinder deviates due to variations in the diameters of the plurality of intermediate shafts, the output rotation center rotates around the original rotation center with a radius corresponding to the deviation amount. For this reason, the rotation on the output side varies due to the shift of the rotation center.
[0005]
[Means for Solving the Problems]
As a countermeasure against this, in the present invention, as described in claim 1, the traction includes a circumscribed shaft, a plurality of intermediate shafts arranged in contact with the outer periphery of the circumscribed shaft, and an inscribed cylinder inscribed in the outer periphery of the intermediate shaft. In drive reducer,
The support for rotatably supporting the intermediate shaft is fixed , the drive motor is connected to at least one of the plurality of intermediate shafts, and the output is extracted from a circumscribed shaft having a diameter larger than the outer diameter of the intermediate shaft. The characteristic traction drive speed reducer eliminates the problems associated with the prior art described above.
[0006]
In the present invention, the rotation is inputted from the intermediate shaft, and the output is taken out from the circumscribed shaft located at the center. That is, the support shaft is set in a fixed state by setting an output shaft which is a circumscribed shaft at the reference output rotation center. With this configuration, even if there are variations in the diameters of a plurality of intermediate shafts, the inscribed cylinder in a free state allows deformation due to variations in the intermediate shaft diameters, so that the centers of rotation are shifted simultaneously. As a result, the fluctuation of the rotation due to the variation in the diameter of the plurality of intermediate shafts does not occur on the circumscribed shaft as the output shaft.
[0007]
The present invention is also applicable to cases where a plurality of outputs are required coaxially. That is, in the traction drive speed reducer comprising a circumscribed shaft, a plurality of intermediate shafts arranged on the outer periphery of the circumscribed shaft, and an inscribed cylinder inscribed on the outer periphery of the intermediate shaft as shown in claim 2,
2 or more circumscribed axes are arranged coaxially, in contact respectively disposed a plurality of intermediate axes on the outer periphery of each of the circumscribed axis, a support for rotatably supporting the rotation each of the plurality of the intermediate shaft and a fixed state, A traction drive speed reducer characterized in that rotation can be input from at least one of the intermediate shafts in a set and output can be extracted from the corresponding circumscribed shaft to extract two or more coaxial outputs. By doing so, it is possible to take out the output without rotational fluctuation from the coaxial output shaft. In particular, a traction drive speed reducer having such an output shaft has extremely excellent characteristics as a drive mechanism of a drive unit of an industrial robot, for example.
[0008]
【Example】
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a first embodiment of the present invention, in which (a) is a schematic sectional view schematically showing the structure of the embodiment, and (b) is a sectional view taken along line AA in (a). Although the circumscribed shaft, the intermediate shaft, and the inscribed cylinder are in contact with each other, in FIG. 1A, for the sake of clarity, a minute gap is formed between them. They are in contact. Further, the carrier is not shown in FIG.
[0009]
In this embodiment, as shown in FIG. 1 (a), a carrier 10 as a support of the present invention is formed in a bowl shape by a pair of upper and lower plates 11 and 12 and a column portion 13 connecting the plates. An output shaft 21 protrudes from the center of the output outer shaft 20, and the output shaft 21 of the output outer shaft 20 is rotatably supported by a bearing 23 positioned at the center of the upper plate 11 of the carrier 10.
[0010]
Around the circumscribed shaft 20, a plurality of (three in the illustrated embodiment) intermediate shafts 30 are arranged equally as shown in FIG. 1B, and contact the outer periphery of the circumscribed shaft 20. Yes. The circumscribed shaft 20 has a diameter larger than the outer diameter of the intermediate shaft 30, and decelerates an input introduced into the intermediate shaft 30 as described later and outputs it from the circumscribed shaft 20.
[0011]
The inner circumference of the inscribed cylinder 40 is inscribed outside the plurality of intermediate shafts 30. Each intermediate shaft 30 is rotatably supported at both ends by bearings 31 provided on upper and lower plates 11 and 12 constituting the carrier 10.
[0012]
A drive motor (not shown) is connected to at least one of the plurality of intermediate shafts 30, and a driving force is introduced into the intermediate shaft 30. On the other hand, the carrier 10 is fixed and the output is taken out from the circumscribed shaft 20.
[0013]
Next, a second embodiment in which a plurality of outputs are extracted coaxially will be described with reference to FIG.
[0014]
FIG. 2 shows a second embodiment according to the present invention, (a) is a schematic cross-sectional view, (b) shows a cross-section at position A in FIG. 2 (a), and (c) shows FIG. 2 (a). The cross section of B position is shown.
[0015]
A carrier 10 composed of a pair of upper and lower plates 11 and 12 is connected by a column portion 13 to form a strong bowl-like state. An output circumscribing shaft 20A having a hollow output shaft 21A and an output circumscribing shaft 20B having an output shaft 21B penetrating the hollow output portion of the output circumscribing shaft 20A are coaxially arranged at the center of the carrier 10.
[0016]
A plurality of intermediate shafts 30A and 30B are arranged around the output circumscribing shafts 20A and 20B, as shown in FIGS. 2B and 2C, and contact the outer periphery of the output circumscribing shafts 20A and 20B. is doing. As shown in FIG. 2A, both ends of the intermediate shafts 30A and 30B are rotatably supported by the carrier 10 by bearings 31A and 31B.
[0017]
Further, inscribed cylinders 40A and 40B are provided outside the respective intermediate shafts 30, and the inner peripheral surfaces of the inscribed cylinders 40A and 40B are in contact with the outer sides of the intermediate shafts 30A and 30B.
Each of the circumscribed shafts 20A and 20B, the plurality of intermediate shafts 30A and 30B, and the inscribed cylinders 40A and 40B form one set. 21B is arranged coaxially.
[0018]
For example, a drive motor (not shown) is connected to at least one of the intermediate shafts 30A and 30B of each set to introduce an input. The carrier 10 is fixedly supported.
[0019]
Thereby, the power input from the intermediate shafts 30A and 30B is decelerated and can be taken out from the output shafts 21A and 21B, respectively. In order to further increase the reduction ratio of the speed reducer, other speed reducers 50A and 50B may be provided between the intermediate shafts 30A and 30B of the respective speed reducers and the drive motor. Even in the case of such a large reduction ratio, according to the present invention, a planar arrangement can be obtained.
[0020]
A third embodiment of the present invention is shown in FIG. In the embodiment shown in FIG. 2, the intermediate shafts 30 </ b> A and 30 </ b> B and the circumscribed shafts 20 </ b> A and 20 </ b> B are supported by the carrier 10 including the pair of upper and lower plates 11 and 12, respectively, but the interval between the upper and lower carriers 10 is increased. If there is a concern, it is preferable to use the embodiment shown in FIG. In this embodiment, the carrier 10 is divided into three plates by further sandwiching one plate 14 between the set of circumscribed shafts 20A, 20B, intermediate shafts 30A, 30B and inscribed cylinders 40A, 40B. It consists of.
[0021]
By doing so, the distance between the bearings 31A, 31A and 31B, 31B of the shaft supporting the intermediate shafts 30A, 30B can be shortened, and the deformation of the intermediate shafts 30A, 30B can be reduced. Can do. Further, the outer inscribed shafts 20A and 20B can be supported at both ends by the bearings 23B provided on the plates 11 and 14 in particular, so that the deformation can be further reduced.
[0022]
In the embodiment described above, the output shafts 21, 21 </ b> A, and 21 </ b> B are uniaxial and biaxial, but the structure of the present invention can be implemented even when the number of output shafts 21 is further increased. An example is shown in FIG. In FIG. 4, the carrier 10 is omitted.
[0023]
In the present embodiment, the circumscribed shaft 20 serving as the output shaft 21 has a triple structure, and there is a second hollow cylinder in the outermost hollow cylinder. 30 penetrates. Since other structures are similar to those shown in FIG. 2 or FIG. 3, detailed description thereof is omitted.
[0024]
【The invention's effect】
According to the present invention, even if there are variations in the diameters of the plurality of intermediate shafts 30, since the output is taken out from the circumscribed shaft 20, the rotational fluctuation of the circumscribed shaft 20 hardly occurs, and thus there is no rotation unevenness. A good speed reducer with uniform rotation can be obtained. Therefore, it is possible to obtain a speed reducer that is extremely effective for an apparatus in which fluctuations in output rotation are a problem.
[Brief description of the drawings]
FIG. 1 shows a first embodiment of the present invention, wherein (a) is a cross-sectional view schematically showing cultivation of the embodiment, and (b) is a cross-sectional view taken along line AA of (a).
2A is a schematic cross-sectional view of the second embodiment of the present invention, FIG. 2B is a cross-sectional view at position A in FIG. 2A, and FIG. ) Shows a cross-section at the B position.
FIG. 3 is a schematic sectional view similar to FIG. 2A, showing a third embodiment according to the present invention.
4A and 4B show a fourth embodiment of the present invention, where FIG. 4A is a schematic cross-sectional view, FIG. 4B is a cross-sectional view at position A in FIG. 2A, and FIG. ) Shows a cross section at the B position, and FIG. 2D shows a cross section at the C position in FIG.
[Explanation of symbols]
10 Carrier (support)
11, 12, 14 Plate 13 Column portion 20, 20A, 20B Output circumscribing shaft 21, 21A, 21B Output shaft 23 Bearing 30, 30A, 30B Intermediate shaft 40, 40A, 40B Inscribed cylinder 31, 31A, 31B Bearing 50A, 50B Decelerator

Claims (2)

In a traction drive speed reducer comprising a circumscribed shaft, a plurality of intermediate shafts arranged in contact with the outer periphery of the circumscribed shaft, and an inscribed cylinder inscribed in the outer periphery of the intermediate shaft,
The support for rotatably supporting the intermediate shaft is fixed , the drive motor is connected to at least one of the plurality of intermediate shafts, and the output is extracted from a circumscribed shaft having a diameter larger than the outer diameter of the intermediate shaft. Features a traction drive reducer. In a traction drive speed reducer comprising a circumscribed shaft, a plurality of intermediate shafts arranged in contact with the outer periphery of the circumscribed shaft, and an inscribed cylinder inscribed in the outer periphery of the intermediate shaft,
2 or more circumscribed axes are arranged coaxially, in contact respectively disposed a plurality of intermediate axes on the outer periphery of each of the circumscribed axis, a support for rotatably supporting the rotation each of the plurality of the intermediate shaft and a fixed state, A traction drive speed reducer characterized in that rotation can be input from at least one of the intermediate shafts in a set and output can be extracted from the corresponding circumscribed shaft to extract two or more coaxial outputs. .

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