JP2646099B2 - Planetary roller type power transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention uses a plurality of planetary rollers formed with a small diameter portion and outputs or inputs power from a differential wheel circumscribed to the small diameter portion. To a planetary roller type power transmission device.

<Prior Art> An example of this type of conventional planetary roller type power transmission device will be described with reference to FIGS. 3 and 4. FIG.

In the figure, reference numeral 1 denotes a sun shaft, on which a single fixed wheel 2 is concentrically fitted. A plurality of planetary rollers 3 are interposed between the fixed wheel 2 and the sun shaft 1 in a pressed state. Each of the planetary rollers 3 is arranged at equal circumferential intervals by a carrier (not shown).

Almost half of the planetary roller 3 on one side in the axial direction has a large diameter.
The other half is formed with a small diameter, and the large diameter portion is denoted by reference numeral 4.
, The small diameter portion is denoted by reference numeral 5. A thin flange 6 having the same diameter as the large diameter portion 4 is formed on the small diameter portion 5 side. The large diameter portion 4 is pressed against the sun shaft 1 and the fixed wheel 2, the flange 6 is pressed against only the sun shaft 1, and the small diameter portion 5
, A differential wheel 7 rotatably arranged is circumscribed. This differential wheel 7 is arranged adjacent to the fixed wheel 2.

In this planetary roller type power transmission device, for example, when the sun shaft 1 is rotated in the direction of arrow A in FIG.
Since the fixed wheel 2 circumscribing the large-diameter portion 4 of the planetary roller 3 is fixed, the planetary roller 3 revolves in the direction of arrow C while rotating in the direction of arrow B. On the other hand, this planetary roller 3
Due to each revolution, the differential wheel 7 pressed against the small-diameter portion 5 is in the same direction as the revolution direction of the planetary roller 3 (arrow D direction).
Rotated. That is, in this case, the planetary roller 3 is decelerated more than the sun shaft 1 which is the input shaft, and the further decelerated power is taken out from the differential wheel 7. Conversely, when the differential wheel 7 is used as an input shaft and the sun shaft 1 is used as an output shaft, greatly increased power is taken out.

Such a planetary roller type power transmission device using the differential wheel 7 is characterized in that a larger reduction ratio or a higher speed ratio can be set as compared with a normal planetary roller type power transmission device not using the differential wheel 7.

<Problems to be Solved by the Invention> However, the conventional example having such a configuration has the following problems.

That is, in the structure using the differential wheel 7, in general, the small-diameter portion 5 of the planetary roller 3 pressed against the large-diameter portion 4 and the large-diameter portion 4 pressed against the fixed wheel 2 during operation are opposite to each other. The force starts to work. Therefore, as described above, a planetary roller 3 having a large diameter portion 4 having substantially half the axial direction and a small diameter portion 5 having almost the other half having a small diameter is used.
In the conventional apparatus using only one, the force for skewing the planetary roller 3 becomes extremely large, resulting in an increase in loss torque.

The present invention has been made in view of such circumstances,
The purpose is to significantly reduce the occurrence of torque loss.

<Means for Solving the Problems> The present invention has the following configuration in order to achieve such an object.

That is, the planetary roller type power transmission device according to the present invention includes:
A large diameter portion of each of the plurality of planetary rollers having a small diameter portion is pressed against a fixed wheel and a sun shaft, and a rotatable differential wheel is circumscribed to the small diameter portion, and power is output or input from the differential wheel. It uses a planetary roller with a small diameter at the center in the axial direction and a large diameter on both sides, and circumscribes a fixed ring on each of the two large diameter parts, and a differential ring on the small diameter part. It is characterized in that the differential wheels are circumscribed and are arranged so as to be rollable on the respective fixed wheels between the two fixed wheels via rolling bearings.

<Operation> The operation of the configuration of the present invention is as follows. A large-diameter portion is provided on both axial sides of the planetary roller, and a small-diameter portion is provided substantially at the center of the planetary roller in the axial direction, so that the large-diameter portions on both sides are interposed between the two fixed wheels and the sun shaft. Therefore, during operation, forces in the same direction act on both ends of the planetary roller, and a force in the opposite direction acts on substantially the center of the planetary roller in the axial direction.

That is, as long as a differential wheel and a stepped planetary roller are used, it is inevitable that a reverse force acts on the planetary roller. However, according to the configuration of the present invention, as described above, In addition, since the forces applied to the planetary rollers can be distributed in a well-balanced manner, almost no force is generated to skew the planetary rollers.

In addition, since the differential wheels are arranged so as to be able to roll through the rolling bearings on each fixed wheel between the two fixed wheels, there is no friction between the differential wheel and the fixed wheel during operation. No image sticking occurs.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

1 and 2 show an embodiment of the present invention.

In these figures, reference numeral 10 denotes a case.
The sun shaft 20 is rotatably supported by the roller shaft 30 via a rolling bearing 30. Reference numerals 40a and 40b denote fixed rings which are fitted around the sun shaft 20 concentrically and are fixed to the case 10. The fixed rings 40a and 40b are arranged apart from each other in the axial direction.

Numeral 50 denotes planetary rollers which are equally arranged circumferentially between the fixed wheels 40a, 40b and the sun shaft 20, and this planetary roller 50 has a small diameter in approximately one-third of the axial center thereof, and the remaining two ends. A region of approximately 1/3 each has a large diameter. The planetary roller 50 is mounted in the hollow portion of the planetary shaft 6 via rolling bearings 31 and 32.
Numeral 0 is inserted so as to be relatively rotatable, and both ends of the planetary shaft 60 are supported by carrier plates 61 and 62 formed of annular plates, respectively. The carrier plates 61 and 62 are rotatable relative to the sun shaft 20 via rolling bearings 33 and 34.

Further, reference numeral 70 denotes a differential wheel circumscribed to each small diameter portion 51 of each planetary roller 50.The differential wheel 70 is disposed between the fixed wheels 40a, 40b, and the rolling bearings 35, 36 are mounted on the two fixed wheels 40a, 40b. It is relatively rotatably mounted via the. The large diameter portions 52, 53 of the planetary roller 50 are circumscribed by two fixed wheels 40a, 40b.

In the planetary roller type power transmission device of this configuration, when the sun shaft 20 is rotated in the direction indicated by the arrow X in FIG. 2 using the sun shaft 20 as an input shaft, the stationary wheels 40a, which are pressed against the large diameter portions 52, 53 of the planetary roller 50, Since 40b is fixed, the planetary roller 50 revolves in the arrow Z direction while rotating in the arrow Y direction. On the other hand, due to the revolution of each of the planetary rollers 50, the differential wheel 70 pressed against the small diameter portion 51 is rotated in the same direction (the direction of the arrow V) as the direction of revolution of the planetary rollers 50.

In other words, in this case, the rotational power that has been significantly reduced from the sun shaft 20, which is the input shaft, via the planetary rollers 50 is extracted from the differential wheel 70, and is used, for example, as a reduction gear for a robot arm. Conversely, when the differential wheel 70 is used as an input shaft and the sun shaft 20 is used as an output shaft, a speed increasing mechanism is provided.

By the way, large-diameter portions 52, 53 are provided on both axial sides of the planetary roller 50.
The small diameter portion 51 is provided substantially at the center in the axial direction of the planetary roller 50, and the fixed wheels are pressed against the large diameter portions 52, 53 on both sides. A force in the same direction acts on the planetary roller 50, and it can be distributed in a well-balanced manner at a substantially axial center of the planetary roller 50 so that a force in the direction opposite to the above acts.

As described above, since the forces applied to the planetary rollers 50 can be distributed in a well-balanced manner, almost no force for skewing the planetary rollers 50 is generated. for that reason,
The occurrence of loss torque caused by this can be greatly reduced as compared with the related art.

<Effects of the Invention> According to the present invention, the following effects are exhibited.

The small-diameter portion of the planetary roller that circumscribes the differential wheel is provided at the center in the axial direction, and the large-diameter portion that circumscribes both sides of the planetary roller in the axial direction with the fixed wheel acts on the large-diameter portion and the small-diameter portion during operation. The forces in the opposite direction are distributed in a well-balanced manner, so that there is almost no force for skewing the planetary rollers. Therefore, the torque loss caused by the skew of the planetary rollers can be made much smaller than in the prior art, so that the transmission torque capacity can be increased without difficulty.

In particular, the differential wheel is arranged between the two fixed wheels on each fixed wheel so as to be able to roll via a rolling bearing so that no friction occurs between the differential wheel and the fixed wheel during operation. Since the occurrence of image sticking is prevented, there is an advantage that high-speed rotation can be performed without any trouble.

[Brief description of the drawings]

1 and 2 relate to an embodiment of the present invention, and FIG.
The figure is a longitudinal sectional view, and FIG. 2 is a sectional view taken along the line II-II in FIG. 3 and 4 relate to a conventional example, FIG. 3 is a view corresponding to FIG. 1, and FIG. 4 is a cross-sectional view taken along line VV of FIG. 20… Sun axis 40a, 40b… Fixed wheel 50… Planetary roller 51… Small diameter part 52,53… Large diameter part 70 …… Differential wheel.

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Claims (1)

(57) [Claims] 1. A large-diameter portion of each of a plurality of planetary rollers having a small-diameter portion is pressed against a fixed wheel and a sun shaft, and a rotatable differential wheel is circumscribed on the small-diameter portion. A planetary roller type power transmission device configured to output or input the outer ring, using a planetary roller having a small diameter in the axial center and a large diameter on both sides, and circumscribing a fixed ring to each of both large diameter portions. A planetary roller type power transmission, wherein a differential wheel is circumscribed on the small diameter portion, and the differential wheel is arranged so as to be able to roll between the two fixed wheels on each of the fixed wheels via a rolling bearing. apparatus.