JPS6317600B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an industrial robot, and particularly to a wrist device thereof.

[Prior art]

FIG. 1 is a sectional view showing a conventional device disclosed in, for example, Japanese Patent Application Laid-open No. 52-105463. In the figure, 1 is a cylindrical link, and 2 is a first drive shaft disposed within this link 1. , 3 is a cylindrical second drive shaft concentrically surrounding this first drive shaft 2, 4 is this second drive shaft.
A cylindrical third drive shaft 5 is connected to one end of the third drive shaft 4 and rotates concentrically with the third drive shaft 4. The second box body 6 rotates on the rotation axis B via the box body and the gear 7→gear shaft 8→gear 9→cylindrical portion 6a. Next, when the first drive shaft 2 rotates, the output member 15 rotates via the gear 10 → gear 11 → transmission shaft 12 → gear 13 → output gear 14. In this way, the output member 15, ie the gripping device, performs a three-dimensional movement. By the way, the second box body 6
In general, a larger rotational force is required than that of the output member 15 when rotating the output member 15 . Therefore, the first drive shaft 2 and the transmission shaft 12, which are small diameter shafts,
5, the output member 15 is rotated by the first drive shaft 2 of the large diameter shaft and the transmission shaft 12, and the second box body 6 is rotated by the second drive shaft 3 of the large diameter shaft and the cylindrical portion 6a. I'm letting you do it.

However, since gear 9 is located on the side of the intersection of axis A and axis B with respect to gear 11, gear 7 and gear 9 are connected by gear shaft 8, which constitutes an intermediate gear that does not contribute to deceleration. Therefore, a large increase in torque cannot be expected with the reduction ratio of gear 7 and gear 9. Therefore, it is necessary to set the input side of the second drive shaft 3 to a high torque in advance, and this high torque is applied to the second drive shaft 3, the gear 7, the gear shaft 8, and the gear 9 in the cylindrical portion 6a, that is, the Due to the strength of these transmission systems, one end of this first
A side plate 5b is formed in which a support portion 5a on an axis oblique to the rotation axis of the box body 5 is provided in the center. Reference numeral 6 denotes a second box body having a cylindrical portion 6a that is rotatably supported on the support portion 5a, and one end has a cylindrical portion 6a on an axis oblique to the rotation axis of the second box body 6. A supporting portion 6b is formed. 7 is a gear connected to the second drive shaft 3; 8 is a gear shaft supported by the first box 5 and meshes with the gear 7; 9 is a gear shaft connected to the gear shaft 8 and connected to the second box 6; A gear coupled to the cylindrical portion 6a, 10 a gear coupled to the first drive shaft 2;
1 is a gear that meshes with this gear 10 and is concentric with the cylindrical portion 6a; 12 is a transmission shaft whose one end is connected to this gear 11 and is disposed concentrically within the cylindrical portion 6a; 13 is a transmission shaft that is concentric with the cylindrical portion 6a; A gear 14 is connected to one end of the shaft 12, and an output gear 14 is disposed on an axis oblique to the transmission shaft 12 and meshes with the gear 13. A gear 15 is connected to the output gear 14 and rotates on the support portion 6b. an output member, such as a gripping device, which can be supported;

In the structure configured as described above, first, when the third drive shaft 4 rotates, the first box 5 rotates on the rotation axis A of the third drive shaft 4. Next, the rotation of the second drive shaft 3 must be set to a large degree, which not only increases the diameter of each shaft and the tooth thickness of the gears, but also increases the backlash of each gear. Compared to the box body 5, the backlash in the rotational direction of the second gear 6 is large, which also has the disadvantage that the operating accuracy of the output member 15 is reduced.

[Summary of the invention]

The present invention was made with the aim of improving such drawbacks, and includes a first drive shaft, a cylindrical second drive shaft concentrically surrounding the first drive shaft, and a second drive shaft that is concentric with and surrounds the first drive shaft.
a cylindrical third drive shaft concentrically surrounding the drive shaft, coupled to the third drive shaft, having an opening at one end, and rotating concentrically with the third drive shaft; a first box to be obtained; a second box supported in the opening and capable of rotating about an axis oblique to the rotational axis of the first box; one end at the bottom of the second box; are combined,
a transmission shaft disposed concentrically with the second box; a cylindrical shaft concentric with and surrounding the transmission shaft; supported by the second box, with the rotation axis of the second box; an output member rotatable about oblique axes; a first bevel gear coupled to the first drive shaft; a first bevel gear meshing with the first bevel gear and coupled to one end of the cylindrical shaft; The second bevel gear is centered at the intersection of the rotational axis of the first box body and the rotational axis of the second box body, and is located outside the position of the first bevel gear. a third bevel gear coupled to the second drive shaft; a fourth bevel gear meshing with the third bevel gear on the outside of the cylindrical shaft;
a fifth bevel gear coupled to the other end of the cylindrical shaft; a sixth bevel gear meshing with the fifth bevel gear and coupled to the output member; and an input side coupled to the fourth bevel gear. and a harmonic reducer whose output side is connected to the other end of the transmission shaft, the second
A wrist device for an industrial robot that can reduce the shaft diameter of the transmission system to the second box and reduce the gears of each gear, reduce backlash in the rotational direction of the second box, and improve the operational accuracy of the output member. This is what we provide.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.
In the figure, 16, 17, 18, 19 are the first
Bearings rotatably support the drive shaft 2, the second drive shaft 3, the first box 5, and the second box 6; 20 is a gear meshing with the box 10; 21 is a gear 20 A cylindrical shaft 22 connected to one end and obliquely perpendicular to the rotation axis of the first box 5 is supported by the second box 6,
a bearing rotatably supporting the other end of the cylindrical shaft 21;
A gear 3 is connected to the other end of the cylindrical shaft 21 and meshes with the output gear 14. 24 is a gear that meshes with gear 7; 25 is a harmonic reducer in which an input shaft 25a is coupled to gear 24, and has an output section 25b.
Reference numeral 26 denotes a transmission shaft having one end connected to the output portion 25b and the other end connected to the bottom 6c of the second box body 6, and is arranged within the cylindrical shaft 21 concentrically therewith. 27 is a bearing that supports the input shaft 25a of the harmonic reducer 25; 28 is a bearing that is supported by the gear 24 and rotatably supports the cylindrical shaft 21; and 29 is supported by the support portion 6b of the second box body 6. These are a pair of bearings that rotatably support the output member 15.

In the configuration as described above, the third
The rotation of the drive shaft 4 is transferred to the first box 5, and the rotation of the second drive shaft 3 is transferred from the gear 7 to the gear 24 to the harmonic reducer 2.
5 → to the second box body 6 via the transmission shaft 26 , and the rotation of the first drive shaft 2 is transmitted to the output member 15 via the gear 10 → gear 20 → cylindrical shaft 21 → gear 23 → output gear 14 is communicated. As a result, the output member 15
is operated in three dimensions. Here, in the gears 7, 24 of the transmission system of the second box 6, the gears 6, 20
On the other hand, the axes of the transmission shaft 26 and the cylindrical shaft 21,
It is located on the opposite side of the intersection with the rotation axis of the first box 5, and the input shaft 25a of the harmonic reducer 25 is coupled to the gear 24, so that the harmonic reducer 25 with a high reduction ratio A desired reduction ratio and torque are transmitted to the second box body 6 via the transmission shaft 26. Therefore, the harmonic reducer 25
The gears and shafts of the transmission system leading to the input shaft 25a can transmit data in a low torque state.

Further, the output member 15, which has a relatively low torque, is driven by the first drive shaft 2 having a small diameter, and each of the drive shafts 2, 3, and 4 transmits a torque that matches the respective shaft strengths.

〔Effect of the invention〕

As described above, the present invention includes a first drive shaft, a cylindrical second drive shaft concentrically surrounding the second drive shaft, and a cylindrical second drive shaft concentrically surrounding the second drive shaft. 3 drive shaft, coupled to this third drive shaft;
a first box having an opening at one end and capable of rotating concentrically with the third drive shaft; an axis supported by the opening and obliquely intersecting with the rotation axis of the first box; a second box that can be rotated, a transmission shaft having one end connected to the bottom of the second box and arranged concentrically with the second box, and a cylinder concentrically surrounding the transmission shaft. a shaped shaft, an output member supported by the second box and rotatable about an axis oblique to the rotation axis of the second box, a first drive shaft coupled to the first drive shaft; a bevel gear; a second bevel gear meshing with the first bevel gear and coupled to one end of the cylindrical shaft; a rotational axis of the first box and a rotational axis of the second box; Centered on the intersection with
a third bevel gear located outside the position of the first bevel gear and coupled to the second drive shaft; a fourth bevel gear meshing with the third bevel gear outside the cylindrical shaft;
a fifth bevel gear coupled to the other end of the cylindrical shaft, a sixth bevel gear meshing with the fifth bevel gear and coupled to the output member, and the fourth bevel gear. Since the harmonic reducer is equipped with an input side connected to the transmission shaft and an output side connected to the other end of the transmission shaft,
Each drive shaft can transmit torque that matches the shaft strength based on its shaft diameter, which is not only extremely efficient, but also because the harmonic reducer serves as the final reduction part in the transmission system of the second box. The shaft and gears can transmit low torque, making it possible to downsize them. Furthermore, since the harmonic reducer serves as the final stage reduction section as mentioned above, by utilizing the characteristics of the harmonic reducer's high reduction ratio and the characteristic of configuring an extremely small backlash, the input of the harmonic reducer can be reduced. Even if the backlash of gears, etc. leading to the shaft is large, the harmonic reducer can almost ignore the backlash, and the backlash in the rotational direction of the second box can be made extremely small, greatly improving the operating accuracy of the output member. There is an effect that can be improved.

In addition, in a configuration in which the fourth bevel gear and the input shaft of the harmonic reducer are integrally coupled and the second bevel gear and the input shaft are supported by a bearing, the second bevel gear and the input shaft may be supported by a bearing. The shaft is supported by one bearing, which has the effect of simplifying the bearing means of the harmonic reducer.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional device, and FIG. 2 is a sectional view showing an embodiment of the present invention. In the figure, 2 is the first drive shaft, 3 is the second drive shaft, 4 is the third drive shaft, 5 is the first box, 6 is the second box, 7, 1
0, 20, 24, 23 are gears, 14 is an output gear,
15 is an output member, 21 is a cylindrical shaft, 25 is a harmonic reducer, 26 is a transmission shaft, and 27 is a bearing. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A first drive shaft, a cylindrical second drive shaft concentrically surrounding the second drive shaft, and a third cylindrical drive shaft concentrically surrounding the second drive shaft. drive shaft, this third
a first box body coupled to the drive shaft of the third drive shaft, having an opening at one end, and capable of rotating concentrically with the third drive shaft;
a second box supported in the opening and rotatable about an axis oblique to the rotation axis of the first box; one end connected to the bottom of the second box; a transmission shaft disposed concentrically with the body; a cylindrical shaft concentrically surrounding the transmission shaft; supported by the second box;
an output member rotatable about an axis oblique to the rotation axis of the second box, a first bevel gear coupled to the first drive shaft, meshing with the first bevel gear; a second bevel gear coupled to one end of the cylindrical shaft, the first bevel gear centered at the intersection of the rotational axis of the first box and the second box; a third bevel gear located outside of the position and coupled to the second drive shaft; a fourth bevel gear meshing with the third bevel gear outside the cylindrical shaft; a fifth bevel gear coupled to the other end of the shaft; a sixth bevel gear meshing with the fifth bevel gear and coupled to the output member; and an input side coupled to the fourth bevel gear; A wrist device for an industrial robot comprising a harmonic reduction gear whose output side is connected to the other end of the transmission shaft. 2. A first drive shaft, a cylindrical second drive shaft concentrically surrounding the second drive shaft, a third cylindrical drive shaft concentrically surrounding the second drive shaft, and a third cylindrical drive shaft concentrically surrounding the second drive shaft; 3
a first box body coupled to the drive shaft of the third drive shaft, having an opening at one end, and capable of rotating concentrically with the third drive shaft;
a second box supported in the opening and rotatable about an axis oblique to the rotation axis of the first box; one end connected to the bottom of the second box; a transmission shaft disposed concentrically with the body; a cylindrical shaft concentrically surrounding the transmission shaft; supported by the second box;
an output member rotatable about an axis oblique to the rotation axis of the second box, a first bevel gear coupled to the first drive shaft, meshing with the first bevel gear; a second bevel gear coupled to one end of the cylindrical shaft, the first bevel gear centered at the intersection of the rotational axis of the first box and the second box; a third bevel gear located outside of the position and coupled to the second drive shaft; a fourth bevel gear meshing with the third bevel gear outside the cylindrical shaft; An input shaft is integrally coupled to a fifth bevel gear coupled to the other end of the shaft, a sixth bevel gear meshing with the fifth bevel gear and coupled to the output member, and the fourth bevel gear. and a harmonic reduction gear whose output side is connected to the other end of the transmission shaft, and a bearing supported by the first box and supporting the input shaft of the harmonic reduction gear and the fourth bevel gear. Wrist device for robots.