JPH07301287A - Inscribed engagement planetary gear mechanism used in controller - Google Patents

Abstract

PURPOSE:To make it usable to a decelerating mechanism of a controller for a joint driver or the like in an industrial robot by installing an easily manufacturable angle backlash reducing means in an inscribed engagement planetary gear mechanism for a travel driving reduction gear of an industrial vehicle. CONSTITUTION:This inscribed engagement planetary gear mechanism consists of two external gears 8a and 8b, a support block 14 installed after piercing through these external gears, a carrier 13 clamped to this support block, an internal gear 10 inscribably engaging with the external gear, three eccentric body shafts 4 piercing through the external gear and supporting it, each gearing 3 installed in an end of each eccentric body shaft, a nion 2 in mesh with this gearing, and an input shaft rotating and driving this pinion. In this constitution, the input shaft is installed as being pierced through with a clearance in a gap with the support block so as to make the pinion come into a state of being cantilevered, while a control rotation of the input shaft rotating clockwise or counterclockwise is decelerated and thereby it is made so as to be taken out as the control rotation of the internal gear or the support block.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internally meshing planetary gear mechanism used in a control device such as a joint drive device for an industrial robot.

[0002]

2. Description of the Related Art In recent years, a large number of industrial robots that perform control operations have been put to practical use. In such joint drive devices for industrial robots, the output rotation of a motor can be greatly reduced to obtain a large torque output rotation. A speed reduction mechanism is required. Also,
Since the forward and reverse rotations are frequently repeated and precise position control is required, the gear transmission of the reduction mechanism is required to have as little angular backlash as possible. Conventionally, an internally meshing planetary gear speed reduction mechanism is well known as a speed reduction mechanism that decelerates the output rotation of a motor to obtain a large torque output rotation. Further, when a large reduction ratio is required as in a drive reducer for driving an industrial vehicle such as a crawler vehicle, as disclosed in Japanese Patent Publication No. 59-1895, etc.,
The first stage deceleration is performed by the simple planetary gear reduction unit in the previous stage,
A two-stage deceleration type internally meshing planetary gear mechanism may be used in which a second stage deceleration unit decelerates the second stage. The internally meshing planetary gear mechanism will be described below with reference to FIGS. 2 and 3.

A pinion 2 is provided at an end portion of an input shaft 1 which is rotationally driven by a motor, and three transmission gears 3 are arranged around the pinion 2 at equal angles so that they can mesh with each other. The transmission gear 3 is attached to the end of the eccentric body shaft 4, and the eccentric body shaft 4 is mounted on the carrier 1 by bearings 5a and 5b.
3 and the support block 14 are rotatably supported.
Two eccentric bodies 6a and 6b are provided near the middle position of the eccentric body shaft 4.
Are arranged 180 degrees out of phase with each other,
External gears 8a, 8b having trochoidal external teeth 7 are rotatably supported by the eccentric bodies 6a, 6b via eccentric body bearings 9a, 9b. The internal gear 10 is the outer pin 1
In the structure shown, the internal gear 10 also serves as an outer case. Here, the outer case supports a sub rocket (not shown) on the outer periphery thereof. The external gears 8a and 8b have an insertion opening 12 whose inner peripheral surface is a curved surface, and a support block 14 is inserted through the insertion opening 12. The carrier 13 is fixed to the end of the support block 14 by a pin 15 and a bolt 16. Bearings 17a are provided between the internal gear 10 and the carrier 13 and between the internal gear 10 and the support block 14,
17b is provided and rotatably supports the internal gear 10. The decelerated rotation of the internal gear 10 is taken out from the rotation take-out portion 18 provided on the outer periphery of the internal gear 10. Bearings 19a and 19b are provided between the input shaft 1 and the carrier 13 and between the input shaft 1 and the support block 14 to position the input shaft 1.

The operation of the above-described inscribed mesh planetary gear mechanism of an industrial vehicle is as follows. The rotation of the motor is transmitted to the input shaft 1, and the rotation of the input shaft 1 is transmitted to the transmission gear 3 via the pinion 2. The number of teeth of the transmission gear 3 is the pinion 2
Is set more than the number of teeth of the
Is rotated at a reduced speed by the ratio of the number of teeth. The transmission gear 3 rotates the eccentric body shaft 4, and the center Og of the external gears 8a and 8b provided on the eccentric body shaft 4 is eccentric by the rotation center Of and e of the input shaft 1, so that the eccentric body shaft 4 Each time it makes one rotation, it swings about the rotation center Of for one rotation. At the same time, the meshing between the outer teeth 7 and the inner teeth composed of the outer pins 11 is shifted by one tooth, and the internal gear 10 is rotated at a reduced speed. Since the illustrated internally meshing planetary gear mechanism is a speed reduction mechanism for driving the industrial vehicle, the decelerated rotation of the internal gear 10 is caused by the rotation take-out section 1.
It is transmitted from the sprocket fixed to 8 to the chain,
It drives an infinite rail. In this example, the number of the external teeth 7 of the external gears 8a and 8b is one less than the number of the external pins 11.

However, such a speed reduction mechanism for driving a drive of an industrial vehicle is actually used to obtain a large reduction ratio and a large torque, and it is an industrial robot that frequently repeats forward rotation and reverse rotation. It was not used as a deceleration mechanism for control devices such as joint drive devices. The traveling drive speed reduction mechanism of the industrial vehicle is suitable as a speed reduction mechanism of the control device in that it can obtain a large reduction ratio and a large torque.
As described above, one of the conditions is that the deceleration mechanism of the control device has a small angle backlash. In this respect, the deceleration mechanism for traveling drive of the industrial vehicle has a large angle backlash, and therefore, as a deceleration mechanism of the control device. Was not usable. This is because the position of the pinion 2 with respect to the three transmission gears 3 is determined because the input shaft 1 is positioned by the bearings 19a and 19b, and the center of a circle passing through the centers of the three transmission gears 3 is input. When the center Of of the shaft 1 is deviated, one of the pinion 2 and the transmission gear 3
This is because a large angular backlash is unevenly generated in meshing with one or two. Further, the center of a circle passing through the centers of the three transmission gears 3 and the center O of the input shaft 1
In order to prevent the deviation from f, a very advanced processing technique is required, which results in a very high cost, and in reality, it was not adopted as the speed reduction mechanism of the control device.

[0006]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a joint drive for an industrial robot by providing a very low-priced angular backlash reducing means to the traveling drive speed reduction mechanism of the industrial vehicle. An object of the present invention is to make it applicable to a deceleration mechanism of a control device such as a device.

[0007]

SUMMARY OF THE INVENTION The present invention is an external gear,
A support block penetrating the external gear, a carrier fixed to the support block, an internal gear that internally meshes with the external gear, and a support that penetrates the external gear.
With an internally meshing planetary gear mechanism consisting of individual eccentric body shafts, transmission gears provided at the ends of the respective eccentric body shafts, pinions that mesh with the transmission gears, and an input shaft that rotationally drives the pinion. There, the pinion is provided so as to penetrate the input block with a gap between it and the support block so that the pinion is in a cantilevered state, and the control rotation of the input shaft that rotates in the forward or reverse direction is reduced to reduce the internal gear or It is characterized in that it is taken out as a controlled rotation of the support block.

[0008]

In general, when the center of the circle passing through the centers of the three transmission gears and the center of the input shaft are deviated, the pinion and one of the three transmission gears are not meshed with each other. An even large angle backlash is about to occur. However, the inventor of the present invention has found that if the angular backlash is unevenly and largely generated in the meshing of the pinion and any one or two of the three transmission gears, the other transmission gears reduce the angular backlash. I noticed that it works to move the pinion in the direction of moving (proportioning the angular backlash). Therefore, in the present invention, the input shaft is provided with a gap between the input shaft and the support block so that the pinion is cantilevered (the pinion is supported only by the rigidity of the input shaft).
As a result, when another transmission gear works to move the pinion in the direction to reduce the angular backlash,
The input shaft bends to make it easier to move the pinion.

[0009]

Embodiments of the present invention will be described below with reference to FIG. The illustrated embodiment has the same structure as the internal mesh planetary gear mechanism used in the traveling drive speed reducer of the industrial vehicle shown in FIGS. 2 and 3 except the input shaft portion and the input shaft support structure. Therefore, in the following, only the input shaft portion and the support structure of the input shaft will be described, and description of other structures will be omitted.

The input shaft 1 includes an input shaft 1a having a pinion 2 at one end and a spline at the other end,
It is composed of a motor output shaft 1b that rotates in the forward and reverse directions, and a spline member 1c that connects the input shaft 1a and the output shaft 1b. The input shaft 1 is provided so as to penetrate the support block 14 with a gap so that the pinion 2 is cantilevered. The pinion 2 is arranged so as to mesh with the three transmission gears 3.

When the input shaft 1 is rotated, the pinion 2 is rotated and the three transmission gears 3 meshing with the pinion 2 are engaged.
Rotates. Here, when the center of the circle passing through the centers of the three transmission gears and the center of the input shaft are deviated from each other, the angular backlash is generated when the pinion 2 is engaged with any one or two of the transmission gears. Is generated unevenly, but another transmission gear works to move the pinion 2 in a direction in which the angular backlash is proportionally distributed. At this time, the pinion 2 does not move if the input shaft 1 is bearing, but in the present invention, since the input shaft 1 is cantilevered, the input shaft 1 is easily bent and the pinion 2 is automatically moved to the angle back. It is possible to move the rush in the direction of apportionment.

The present invention can be used not only as a speed reducer but also as a speed up gear as in the prior art. Further, the input shaft 1 may be an extension of the output shaft of the motor. The output rotation may be taken out by fixing the support block 14 and taking out the rotation of the internal gear 10 from the take-out portion 18, or by fixing the internal gear 10 side to the support block 1
The 4th side may be used as the rotation take-out section.

[0013]

[Effect] By providing the input shaft with a gap between it and the support block so that the pinion is cantilevered, it is possible to prevent large occurrence of non-uniform angular backlash, and to reduce the large reduction ratio, The traveling drive reduction mechanism of the industrial vehicle that can obtain a large torque can also be applied as the reduction mechanism of the control device. Further, since the input shaft is provided so as to penetrate the support block, the length of the control device in the axial direction is shortened, and accordingly, the total length of the controlled object such as the robot can be shortened.

[0014]

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an internally meshing planetary gear mechanism used in a control device of the present invention.

FIG. 2 is a cross-sectional view showing an internally meshing planetary gear mechanism of a known drive reducer for an industrial vehicle.

3 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

 1 Input shaft 2 Pinion 3 Transmission gear 4 Eccentric body shaft 5 Bearing 6 Eccentric body 7 External tooth 8 External tooth gear 9 Eccentric body bearing 10 Internal gear 11 Outer pin 12 Insertion hole 13 Carrier 14 Support block 15 Pin 16 Bolt 17 Bearing 18 Rotary take-out part 19 Bearing

Claims (1)

[Claims] 1. An external gear, a support block provided through the external gear, a carrier fixed to the support block, an internal gear internally meshing with the external gear, and From three eccentric body shafts penetrating and supporting the external gear, transmission gears provided at the ends of the respective eccentric body shafts, pinions that mesh with the transmission gears, and an input shaft that rotationally drives the pinion. In the intermeshing planetary gear mechanism, the input shaft is provided so as to penetrate the input block with a gap between the input block and the support block so that the pinion is in a cantilevered state, and the control rotation of the input shaft that rotates in the forward and reverse directions is performed. An internal mesh planetary gear mechanism used in a control device, wherein the internal gear and the support block are extracted as controlled rotations.