JPS6334090A - Wrist mechanism of industrial robot - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a wrist mechanism for an industrial robot, and in particular to adjusting the meshing position of the wrist from the outside and miniaturizing the bevel gear meshing position adjustment mechanism. This invention relates to a wrist mechanism for an industrial robot suitable for use in industrial robots.

[Conventional technology]

Conventionally, the wrist of industrial robots was made by
There is a technique disclosed in Japanese Patent No. 0822. In this prior art, power is transmitted from the rotational drive shaft of one wrist to the power transmission shaft, and further from the power transmission shaft to the tip shaft of the wrist, respectively, through a pair of bevel gears.

However, the prior art does not disclose a bevel gear meshing position adjustment mechanism that finely adjusts the meshing position of the bevel gear from the outside of the wrist.

Generally, in a wrist that does not have a mechanism for adjusting the meshing position of the bevel gears, when the meshing of the bevel gears is poor, the wrist is disassembled and a shim is inserted on the surface of the fastening part to change the meshing position of the bevel gears.

[Problem that the invention seeks to solve]

As mentioned above, in the conventional technology that does not have a mechanism for adjusting the meshing position of bevel gears, adjusting the meshing position of the bevel gears in the two pairs of bevel gears accounts for a large portion of the cost for assembling and maintaining the wrist.

In other words, in the conventional technology, when adjusting the meshing position of bevel gears by inserting shims, the adjustment work involves assembling the wrist, checking the meshing of the bevel gears, and if the meshing is poor, disassembling it and replacing the shims. This adjustment process, which requires a trial-and-error method of changing the thickness, increases the cost of assembling and maintaining the wrist.

An object of the present invention is to solve the problems of the prior art and provide a wrist mechanism for a small industrial robot that can adjust the meshing position of a pair of bevel gears without disassembling the wrist.

[Means for Solving the Problems] The object is to provide a spring for pushing a bevel gear attached to the power transmission shaft in the slanate direction at least at one end of the power transmission shaft, and a spring for pushing the bevel gear attached to the power transmission shaft in the slanut direction, A bevel gear meshing position adjusting mechanism is provided, which has a screw formed in the shaft and a nut screwed into the screw and can be adjusted from the outside of the wrist, and the bevel gear attached to the power transmission shaft,
This is achieved by arranging the blades in the direction in which a smaller thrust force is applied among the thrust forces of different directions and magnitudes generated when the pair of bevel gears rotate.

[Effect]

In the present invention, by tightening or loosening the nut of the bevel gear engagement position adjustment mechanism, the bevel gear attached to the power transmission shaft is displaced in the axial direction of the power transmission shaft. Thereby, the meshing position of the bevel gear attached to the power transmission shaft can be adjusted with respect to the bevel gear attached to the rotational drive shaft and the bevel gear attached to the driven shaft.

In addition, in the present invention, since the bevel gear meshing position adjustment mechanism can be adjusted from outside the wrist, there is no need to disassemble the handle when adjusting the meshing position of the bevel gears, and therefore, it is possible to assemble and maintain the wrist. In addition, in the present invention, the bevel gear attached to the power transmission shaft is connected to a spring for adjusting the meshing position of the bevel gears, and thrusts of different directions and magnitudes occur when the pair of bevel gears rotates. Since the spring of the bevel gear engagement position adjustment mechanism is arranged in the direction in which the smaller thrust force is applied, the spring of the bevel gear engagement position adjustment mechanism can be made smaller. Thereby, the bevel gear meshing position adjustment mechanism can be downsized,
Accordingly, the entire wrist mechanism can be downsized.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional view showing one embodiment of the present invention, FIG. 2 is an external view of an industrial robot to which the present invention is applied, and FIG.
An enlarged sectional view of a part of the figure, No. 4 (A) and (B) are explanatory diagrams showing the relationship between the arrangement direction of the bevel gears attached to the power transmission shaft and the thrust force generated when the bevel gear pair rotates. be.

The industrial robot shown in FIG. 2 includes a robot body 1, an upper arm 2, a forearm 3, and a wrist 4.

The robot body 1 is rotated by a rotation drive motor 5.

The upper arm 2 is driven by an upper arm drive motor 6 and a ball screw 7.

The forearm 3 includes a forearm drive motor 8, a ball screw 9,
It is configured to be driven by a forearm drive link 10.

Power is transmitted to the wrist 4 from a wrist drive motor 11. Further, as shown in FIG. 1, the wrist 4 has a housing 12 that accommodates various members constituting the wrist mechanism.

Inside the forearm 3, as shown in FIG. 1, a rotational drive shaft 13 for the wrist 4 is supported. The rotational drive shaft 13
As shown in FIG. 1, a bending drive shaft 16 for the wrist 4 is fitted onto the outer circumference of the forearm 3.
is supported inside. - housing 12 of car wrist 4;
As shown in FIG. 1, the power transmission shaft 14 and the wrist 4
A driven shaft 15, which is a distal end shaft, is supported.

The rotary drive shaft 13 and the bending drive shaft 14 are configured to be able to rotate independently and reversibly around a rotary shaft 17 shown in FIG. 1.

In this embodiment, both ends of the power transmission shaft 14 are supported by the housing 12 via bearings 20 and 21 that are movable in the thrust direction.

As shown in FIG. 1, power is transmitted from the rotary drive shaft 13 to the power transmission shaft 14 through a first bevel gear pair 22. The first bevel gear pair 22 includes a bevel gear 23 attached to the rotary drive shaft 13 and a bevel gear 2 attached near one end of the power transmission shaft 14.
It is constructed by interlocking 4.

As shown in FIG. 1, power is transmitted from the power transmission shaft 14 to the driven shaft 15 through a second bevel gear pair 25. The second bevel gear pair 25 includes a bevel gear 26 attached near the other end of the power transmission shaft 14.
and a bevel gear 2 attached to one end of the driven shaft 15.
It is constructed by interlocking 7.

The driven shaft 15 reversibly rotates around a rotating shaft 19 shown in FIG. 1, and its rotational speed is reduced by a first speed reducer 28 and transmitted to the first wrist 4.

From the bending drive shaft 16, as shown in FIG.
Power is transmitted to the second reduction gear 32 through a pair of gears 29 . This third gear pair 29 includes a bevel gear 30 attached to the end of the bending drive shaft 16 and a second bevel gear 30 attached to the end of the bending drive shaft 16.
It is constructed by meshing with a bevel gear 31 attached to the input side of a reduction gear 32.

The second speed reducer 32 is configured to reduce the power transmitted from the third gear pair 29 and transmit it to the bending rotary plate 33 attached to the 8-force side.

The bending rotary plate 33 is adapted to reversibly rotate the wrist 4 around the bending axis 18 shown in FIG.

Note that, as shown in FIG. 1, a cylindrical shaft 34 is disposed on the outer side of a substantially intermediate portion of the power transmission shaft 14. One end of this cylindrical shaft 34 is brought into contact with the second reduction gear 32 through a flange 34'.

A first bevel gear meshing position adjustment mechanism 35 is provided at one end of the power transmission shaft 4, and a second bevel gear meshing position adjustment mechanism 40 is provided at the other end. Further, the driven shaft 15 is provided with a third bevel gear engagement position adjustment mechanism 46 .

Furthermore, a fourth bevel gear engagement position adjustment mechanism 50 is provided on the cylindrical shaft 34 disposed approximately in the middle of the power transmission shaft 14.
is provided.

As shown in FIGS. 1 and 4(A), the first bevel gear engagement position adjustment mechanism 35 includes a screw 36 formed at the end of the power transmission shaft 14 and a nut screwed into the screw 36. 37, a disc spring 38 attached to the outer periphery of the power transmission shaft 14, and a sleeve 39 interposed between the bevel gear 24 attached to the power transmission shaft 14 and the disc spring 38. In this first bevel gear meshing position adjustment mechanism 35, the bearing 20 and the disc spring 3 can be adjusted by loosening the nut 37.
8, sleeve 39, and bevel gear 24 move together in the direction of arrow a in FIG. At the same time, the bevel gear 24 moves in the opposite direction to the arrow a, and the meshing position of the bevel gear 24 with respect to the bevel gear 23 can be adjusted.

The second bevel gear engagement position adjustment mechanism 40 is.

As shown in FIG. 1, FIG. 3, and FIG. 4 (A), a screw 41 formed at the other end of the power transmission shaft 14, a nut 42 screwed therein, a bearing 21, and an umbrella The spacer 43 provided between the gears 26, the disc spring 45, and the bevel gear 26
and a sleeve 44 interposed between the disc spring 45. In this second bevel gear meshing position adjustment mechanism 40,
By tightening the nut 42, the bevel gear 26 moves together with the bearing 21, spacer 43, and sleeve 44 in the direction of the arrow in FIG. 1, and by loosening the nut 42, the bearing 21 and the second bevel gear The bevel gear 26 moves in the opposite direction as shown by the arrow together with the constituent members of the gear meshing position adjustment mechanism 40, so that the meshing position of the bevel gear 26 with respect to the bevel gear 27 can be adjusted.

As shown in FIG. 1, the third bevel gear engagement position adjustment mechanism 46 includes a screw 47 formed at the end of the driven shaft 15
And the nut 48 screwed into this.

It has a disc spring 49 interposed between two bearings that support the driven shaft 15. In this third bevel gear meshing position adjustment mechanism 46, by tightening or loosening the nut 48, the bevel gear 27 moves together with the member attached to the driven shaft 15 due to the action of the disc spring 49. , so that the meshing position of the bevel gear 27 with respect to the bevel gear 26 can be adjusted.

As shown in FIG. 1, the fourth bevel gear engagement position adjustment mechanism 5o includes a screw 51 formed on the cylindrical shaft 34, a double neck 52 with a U-shaped cross section screwed onto the screw 51, and a screw 52 on the cylindrical shaft 34. It includes a disc spring 54 interposed between the bearing and the second speed reducer 32. A set screw 5 is attached to the double nut 52.
3 is installed. In this fourth bevel gear meshing position adjustment mechanism 50, after removing the set screw 53, by tightening or loosening the double nut 52, the cylindrical shaft 3
The bevel gear 31 moves together with the members attached to the bevel gear 3.
The meshing position of the bevel gear 31 can be adjusted with respect to 0, and after adjustment, a set screw 53 is inserted into the double nut 52.
It is designed to be stopped by screwing it in.

In this embodiment, a second nut is provided inside the double nut 52.
A disc spring 45 of a bevel gear engagement position adjustment mechanism 40 is housed therein.

The bevel gears 24 and 26 attached to the power transmission shaft 14 are connected to the disc springs 38 and 45 of the corresponding node 1 and the second bevel gear engagement position adjustment mechanism 35 and 40, respectively, and the bevel gears 23 and 26 of the other party. Among the thrust forces of different directions and magnitudes that are generated when rotating while meshing with 27, the lower thrust force is applied.

Now, looking at the bevel gear 26, when the bevel gear 26 is rotated in the forward or reverse direction with the bevel gears 26 and 27 in mesh, as shown by arrows 55 and 56 in FIG. 4(A), Thrust forces of different direction and magnitude are generated. Here, when the bevel gear 26 is arranged in the direction shown in FIG. 4(A), the large thrust force shown by the arrow 55 is not added to the disc spring 45 of the second bevel gear meshing position adjustment mechanism 40. A small thrust force, indicated by arrow 56, is added.

On the other hand, when the bevel gear 26 is oriented in the direction shown in FIG.
Instead, a large thrust force shown by the arrow 55° is added, and it is necessary to increase the size of the disc spring 45 to correspond to this.

The wrist mechanism of the above embodiment operates and functions in a first order manner.

First, during assembly and maintenance, the first. Bevel gear 24.2G of the second and third bevel gear pair 22, 25.29,
When adjusting the meshing position of 27.31, operate as follows.

That is, when adjusting the meshing position of the bevel gears 24 of the first bevel gear pair 22, loosen or tighten the nut 37 screwed onto the screw 36 of the first bevel gear meshing position adjustment mechanism 35. As a result, the bearing 20 moves in the axial direction of the power transmission shaft 14 due to the action of the disc spring 38, and as a result, the bevel gear 24 together with the sleeve 39 is strongly applied to the bevel gear 23 as shown by arrow a in FIG. It moves in the direction of engagement or in the direction of loose engagement opposite to the arrow a.

As a result, the meshing position of the bevel gear 24 with respect to the bevel gear 23 can be adjusted.

Next, when adjusting the meshing position of the bevel gear 26 of the second bevel gear pair 25, by tightening the nut 42 screwed into the screw 41 of the second bevel gear meshing position adjustment mechanism 40, Bearing 21, spacer 43 and sleeve 4
4, the bevel gear 26 compresses the disc spring 45 and moves in the direction of strongly meshing with the bevel gear 27 as shown by the arrow in FIG.
Due to this action, the bevel gear 26 moves together with the bearing 21 and the constituent members of the second bevel gear meshing position adjustment mechanism 4o in the opposite direction of the arrow, that is, in the direction of loose meshing with the bevel gear 27. As a result, the meshing position of the bevel gear 26 with respect to the bevel gear 27 can be adjusted.

Further, when adjusting the meshing position of the bevel gear 27 of the second bevel gear pair 25, the nut 48 screwed onto the screw 47 of the third bevel gear meshing position adjustment mechanism 46 is tightened or loosened. As a result, the bevel gear 27 moves together with the members attached to the driven shaft 15 in a direction in which it is strongly engaged with the bevel gear 26 or in a direction in which it is loosely engaged with the bevel gear 26 through the expansion and contraction action of the disc spring 49.

As a result, the meshing position of the bevel gear 27 with respect to the bevel gear 26 can be adjusted.

In this embodiment, the adjustment of the meshing position of the bevel gears 24, 2627 can be performed entirely outside the wrist. When adjusting the meshing position of the bevel gear 31 of the third bevel gear pair 29, , before assembling or disassembling the housing 12, the fourth bevel gear engagement position adjustment mechanism 5 is installed.
With the set screw 53 of the double nut 52 of 0 removed,
By tightening or loosening the double nut 52, the bevel gear 31 together with the members attached to the cylindrical shaft 34 moves in the direction of strong meshing or loose meshing with the bevel gear 30 by the action of the disc spring 54. Next, after adjusting the meshing position of the bevel gear 3 with respect to the bevel gear 30, the set screw 53 is screwed into the double nut 52 to fix it.

After adjusting the meshing position of the bevel gears of each pair of bevel gears, when the rotational drive shaft 13 of the wrist 4 is rotated in the forward or reverse direction,
As shown in FIG. 1, power is transmitted to the power transmission shaft 14 through the bevel gears 23 and 24 forming the first bevel gear pair 22.

When the power transmission shaft 14 rotates in the forward or reverse direction, the bevel gears 26 and 27 forming the second bevel gear pair 25
Then, when the driven force 15 rotates in the forward or reverse direction, its rotational speed is reduced by the first reducer 28 and transmitted to the wrist 4, 4 is the rotating shaft 19 shown in FIG.
Rotate forward or backward around.

Furthermore, when the bending wheel 16 of one wrist 4 is rotated in the forward or reverse direction, as shown in FIG.
Power is transmitted to the second reduction gear 32 through the bevel gears 30 and 31 forming the gear 9, and is decelerated by the second reduction gear 32.

Then, the power is transmitted from the second speed reducer 32 to the bending rotary plate 33, and the bending rotary plate 33 causes the wrist 4 to move to the first position.
Rotation is performed around a bending axis 18 shown in the figure.

In this embodiment, the first. Second bevel gear pair 22.25
*Gear 2 attached to the power transmission shaft 14 in
4 and 26, among the thrust forces of different directions and magnitudes generated when the first and second bevel gear pair 22.25 rotate reversibly, the smaller thrust force adjusts the meshing position of the first and second bevel gears. It is arranged to act on a disk spring 38.45 of the mechanism 35.40. Therefore, the device spring 38.degree. 45 can be downsized, and accordingly, the entire wrist mechanism can be downsized.

Further, in this embodiment, a double nut 52 having a cross-section-mouth type is screwed onto the screw 51 of the fourth bevel gear meshing position adjusting mechanism 50, and a disc of the second bevel gear meshing position adjusting mechanism 40 is inserted into the inside of this double nut 52. Since the spring 45 is accommodated, further miniaturization can be achieved.

In addition, in the present invention, the first. Only one of the second bevel gear engagement position adjusting mechanisms 35 and 40 may be adjustable from outside the wrist 4.

Further, in each of the bevel gear engagement position adjustment mechanisms, other springs may be used instead of the disc springs.

〔Effect of the invention〕

According to the present invention described above, by tightening or loosening the nut of the bevel gear engagement position adjustment mechanism, the bevel gear attached to the power transmission shaft can be displaced in the axial direction of the power transmission shaft.

This has the effect of appropriately adjusting the meshing position of the bevel gear attached to the power transmission shaft with respect to the bevel gear attached to the rotational drive shaft and the bevel gear attached to the driven shaft. .

Further, according to the present invention, since the bevel gear meshing position adjustment mechanism can be adjusted from outside the wrist, there is no need to disassemble the wrist when adjusting the meshing position of the bevel gears, and therefore it is not necessary to assemble the wrist. This has the effect of making maintenance easier.

Moreover, according to the present invention, the bevel gear attached to the power transmission shaft is connected to the spring of the bevel gear engagement position adjustment mechanism to absorb thrust forces of different directions and magnitudes generated when the bevel gear pair rotates. .

Since it is arranged in the direction where a small thrust force is applied, the spring of the bevel gear engagement position adjustment mechanism can be made small. As a result, the bevel gear engagement position adjustment mechanism can be made smaller, and the wrist mechanism as a whole can therefore be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing one embodiment of the present invention, FIG. 2 is an external view of an industrial robot to which the present invention is applied, and FIG.
An enlarged cross-sectional view of a portion of the figure, and FIGS. 4(A) and 4(B) are explanatory diagrams showing the relationship between the arrangement direction of the bevel gears attached to the power transmission shaft and the thrust force generated when the bevel gear pair rotates. It is. 4... wrist of industrial robot, 2... wrist housing, 13... co-rotating drive shaft, 14... co-power transmission shaft, 15... driven shaft as tip shaft of wrist, 22゜25...First and second bevel gear pair, 24.26...Bevel gear attached to the power transmission shaft, 35...First bevel gear meshing position adjustment mechanism, 36... Screw, 37・
...Natsuto, 38...Plate as a spring, 40...
・Second bevel gear meshing position adjustment mechanism, 41...screw, 42...nut, 4S...disc spring as spring, 55.56...slus acting on disc spring,) No. 2 Figure

Claims (1)

[Claims] 1. An industry in which power is transmitted from the rotational drive shaft of the wrist to the power transmission shaft through a first pair of bevel gears, and from the power transmission shaft to the driven shaft, which is the tip end shaft of the wrist, through a second pair of bevel gears. In the wrist mechanism of the robot for use in the robot, at least one end of the power transmission shaft includes a spring that pushes a bevel gear attached to the power transmission shaft in a thrust direction, and a screw formed at the end of the power transmission shaft. , a bevel gear engagement position adjusting mechanism is provided which has a nut threaded thereon and which can be adjusted from the outside of the wrist, and a bevel gear meshing position adjustment mechanism is provided in which the bevel gear attached to the power transmission shaft is connected to the spring. A wrist mechanism for an industrial robot, characterized in that the wrist mechanism is arranged in a direction where a small thrust force is applied among thrust forces of different directions and magnitudes generated when the robot rotates.