JPS639955B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to the structure of a joint connecting a first arm and a second arm of a multi-jointed industrial robot, and more particularly, to The present invention relates to a structure of the joint portion of a portable robot that is easy to use.

[Prior art]

An example of a conventionally used multi-jointed industrial robot will first be described with reference to FIGS. 1 and 2. In the drawing, 1 is a base, 2 is a rotating table that rotates on the base 1, and 3 is a first unit that swings around a joint shaft 4 provided on the rotating table 2.
Arm 5 is a second arm that swings about a joint shaft 6 provided at the end of the first arm 3. 1st
The arm 3 is swung by a drive member 7 via pulleys 9, 10 and a timing belt 13. The second arm 5 also connects pulleys 11 and 12, a timing belt 14, a chain 16 and a sprocket (see FIG. 4 for the chain 16 and sprocket 15, and the sprocket for driving the chain 16 is not shown). It is swung by the drive source 8 via the drive source 8. The drive source 41 is connected to a chain 30 (see FIG. 4) via pulleys 42, 43, a timing belt, and a sprocket (not shown).
The chain 30 drives the bending axis of the wrist via the sprocket and chain. Drive source 51
is connected to the chain 32 via pulleys 52, 53, a timing belt 54, and a sprocket (not shown).
(See Fig. 4), and the chain 32 drives the wrist swing axis via the sprocket and chain.

Next, an example of a joint portion connecting a first arm and a second arm of a conventional portable multi-jointed industrial robot will be described with reference to FIGS. 4 and 5.

The joint shaft 6 connecting the first arm 3 and the second arm 5 has bearings 24 and 6 which have a boss 26 fitted inside.
The first arm 3 is rotatably supported via the first arm 3. The end of the second arm 5 is branched into two parts, each of which has a joint shaft insertion hole. Also,
Each branch end is attached for assembly work described below.
As shown in FIG. 5, a notch groove of equal width is provided in the diameter of the joint shaft insertion hole which communicates with the joint shaft insertion hole from the side surface. The branched end of the second arm 5 is fixed to the joint shaft 6 by fitting the joint shaft 6 into the front hole inside the bearings 24 and 20 with the first arm 3, respectively. The fixing procedure will be described later. Between the two branched ends of the second arm 5 are sprockets 15, 19, 20, which are part of the second arm and wrist drive means.
is installed. The sprocket 15 is prevented from rotating on the joint shaft 6 by a key 28, and a retaining ring 2
The joint axis 6 is fixed in its axial position by 9.
is fixed. A chain 16 is stretched around the sprocket 15, and is driven by the drive source 8 as described above to swing the second arm 5. The sprockets 19 and 20 are supported on the joint shaft 6 by bearings 34 and 35, respectively, through chains 30 and 31 and 32 and 33, and form part of the driving means for the bending and swinging shafts of the wrist as described above. .

Next, other structures of the joints of the robot shown in FIGS. 4 and 5 will be explained together with the assembly procedure. First, assemble the sprockets 15, 19, 20 to the joint shaft 6,
The subassembly is attached to the bearings 24, 60 of the first arm 3.
into the hole 36. Bearing 24, 60
A boss 26 having a joint shaft insertion hole is fitted therein. The joint shaft 6 is inserted into the joint shaft insertion hole from the outside of the bearings 24 and 60, and the joint shaft 6 is inserted into the hole 36 of the first arm 3.
Insert inside. The bearings 24 and 60 are located at the step 2 of the hole 36.
5, but at this point, the bearing 2
A gap is left between the inner end surfaces of 6 and 60 and the stepped portion 25, which is larger than the depth h of the spigot portion 39 (described later). Next, align the notch groove of the second arm 5 with the joint shaft 6 and insert it, and once the joint shaft 6 is inserted into the joint shaft insertion hole of the second arm 5, press the boss 26 until the above-mentioned gap disappears. bearing 24 fitted with
60 to fit the spigot part of the boss 26 and the spigot part of the second arm 5. 2nd arm 5
Since it is not fixed directly to the joint shaft 6 but via the boss 26, the pilot part 39 is necessary to align the arm 5 and the boss 26. Next, the joint is assembled by tightening the second arm 5 and the boss 26 with the bolt 40, inserting the key 27 between the boss 26 and the joint shaft 6, and tightening the boss 26 to the joint shaft 6 with the nut 38. Complete.

In the conventional robot shown in FIGS. 4 and 5, fitting of the pilot part 39 during joint assembly is a blind operation, which is very disadvantageous in terms of assembly work.
Further, as shown in FIG. 5, it is necessary to cut out the pilot part of the second arm 5, which makes machining difficult. The notch in the pilot part is a problem in terms of burr removal and accuracy, and it also reduces rigidity.

Furthermore, there is a problem in that the torque that drives the second arm 5 is transmitted from the joint shaft 6 to the key 27 to the boss 26.
-> bolt 40 -> second arm 5, the rigidity of this part is low, causing a decrease in the positioning accuracy of the robot's wrist. In addition, the material of the boss 26 must be steel due to the surface pressure of the key part, which increases the weight.Also, since the key 27 is long, the width of the first arm 3 becomes large. There is.

Considering the case where the notch of the second arm 5 of the joint part of this robot is eliminated, the sprockets 19, 15 are inserted into the joint shaft 6 with the joint shaft 6 inserted halfway into the first arm 3 and the second arm 5. , 20 in order, the joint shaft 6 may be completely inserted into the joint shaft insertion holes of the first arm 3 and the second arm 5 and fixed. However, this task is extremely difficult in practice, and disassembly is almost impossible.

[Purpose of the invention]

An object of the present invention is to provide a structure for the joints of an articulated robot that allows the joints of the first and second arms to be easily disassembled and assembled without special processing such as cutting out parts. It is on offer.

Another object of the present invention is to provide a structure for the joint portion of an articulated robot that is lightweight and easy to transport.

[Summary of the invention]

The structure of the joint part of the articulated robot of the present invention is constructed as follows. "In a device in which a second arm is rotatably supported by a first arm made of a light alloy via a joint shaft and a bearing provided on the joint shaft, the end of the second arm A hole is bored in each of the branched end parts formed by bifurcating into two parts, and the joint shaft is fixed to only one of the holes by being prevented from rotating through a key, and the joint shaft is A sprocket for driving the second arm, wrist, etc. is attached between the two branch ends, and the other hole of the holes provided in the branch end is larger than the outer diameter of the sprocket. The flange is fitted into the hole and has a joint shaft insertion hole, and the outer peripheral edge thereof is locked to the step. The bearing insertion hole of the first arm has a diameter larger than the outer diameter of the flange, and the bearing insertion hole inserts the joint shaft through a boss having a bearing and a joint shaft insertion hole. The sprocket is rotatably supported, and the joint shaft can be disassembled and assembled through the bearing insertion hole and the stepped hole while the sprocket remains fixed to the joint shaft.

[Embodiments of the invention]

Hereinafter, the structure of the joint part of the articulated robot of the present invention will be explained based on FIG. 3 of the drawings of the embodiment. The joints of the articulated robot shown in FIG. 3 belong to the same category as the joints of the articulated robot shown in FIG. 4, and perform the same operations as the joints of the robot. Therefore, the structure is the same as that of the joint shown in FIG. 4 except for the constituent parts that are the features of the present invention.
Therefore, the same components are indicated by the same reference numerals, and redundant explanation will be omitted.

In the joint portion of this robot, the second arm 5 is made of a light alloy casting to reduce weight. Therefore, a steel embedded bush 17 is cast into the light alloy of the second arm 5 on the inner wall of the joint shaft insertion hole at one branch end (upper side in FIG. 3) of the second arm 5 that transmits the driving torque. There it is. A groove is provided on the outer periphery of the embedded bush 17 for rotation prevention and axial positioning, thereby providing means for preventing rattling between the bush 17 and the main body of the second arm 5. Also,
A key groove into which a key 27 is inserted is provided between the joint shaft 5 and the joint shaft 5.

A joint shaft insertion hole 21 larger than the outer diameter of the sprockets 15, 19, and 20 is provided at the other branch end (lower side in FIG. 3) of the second arm 5.
The diameter is further increased on the outside, and a stepped portion 22 is formed. A flange 23 having a joint shaft insertion hole,
It is fitted onto the joint shaft 6 with its outer peripheral edge locked to the stepped portion 22. The joint shaft 6 is positioned relative to the second arm 5 by the insertion hole of the embedded bush 17 and the insertion hole of the flange 23.

Hole 3 into which the bearings 24, 60 of the first arm 3 are fitted
No. 6 has an inner diameter larger than the outer diameter of the hole at the second arm branch end, and a step 25 is attached to make the outer diameter even larger. Bearings 24 and 60 are each
It is inserted into the hole 36 of the arm 3 and locked to the stepped portion 25. A boss 26 having a joint shaft insertion hole 37 is pushed into the inner peripheral surface of the bearings 24 and 60 from the outside and is fitted into the bearings 24 and 60 with the outer flange. This positions the joint shaft 6 with respect to the first arm 3. Therefore, the joint shaft 6 is supported with respect to the first arm 3 by the bearings 24 and 26, and by further inserting the key 27, the joint shaft 6 and the second arm 5 are fixed in the rotational direction, and the joint shaft 6 and the second arm 5 are fixed to the nut 38. By tightening the boss 26, the first arm 3 and the second arm 5 are fixed in the axial direction.

To explain the assembly order, first, the sprockets 15, 19, 20 and the flange 23 are attached to the joint shaft 6 (the flange 23 may be attached after being inserted into the hole of the arm) to form a partial assembly. Next, the first arm 3 and the second arm are placed in the connection position,
The above-mentioned sub-assembly is replaced with a second one having a larger diameter hole 21.
Insert into the holes of the first arm 3 and the second arm from the arm branch end side (lower side in Figure 3), and insert the flange 2
3 is engaged with the stepped portion 22 of the hole 21 of the second arm 5. Next, the bosses 26 are press-fitted into the inner peripheral surfaces of the bearings 24 and 60, the shaft 6 is inserted into the hole 37 of the boss 26, the shaft 6 is inserted into the hole 36 of the first arm, the key 27 is inserted, and the nut 38 is tightened. Assembly is completed by tightening.

With this structure of the joint, no special notches are provided in the parts, and the joint can be easily disassembled and assembled. In addition, since the torque is transmitted without going through the boss 26, the material of the boss 26 is made of a light alloy, and since the material can be stolen, the weight is reduced, and the width of the first arm is reduced.

〔Effect of the invention〕

Since the joints of the articulated robot according to the present invention are constructed and operated as described above, and can be disassembled and assembled, no special processing such as cutouts is applied to the parts, making it easy to manufacture and easy to disassemble. - It can be easily assembled and is suitable as a structure for joints in portable robots. In addition, since the second arm is made of light alloy, it is possible to reduce the weight, and torque is transmitted to the second arm without going through the boss.
This has the effect of increasing the rigidity of the second arm driving means and improving the positioning accuracy of the robot.

Reducing the weight of the second arm not only has the effect of simply reducing the weight of the portable robot and making it easier to transport, but can also bring about even more significant effects. That is, to give one example, the entire weight of a portable robot is about 40 kg, and the weight of tools such as a torch attached to the wrist is limited to about 2.5 kg due to its structure. Here, if the weight of the second arm is reduced by 1 kg, the weight of the tool will be reduced by approximately 1 kg.
This means that tools such as torches with even better functions can be installed, and work efficiency can be significantly improved.

As described above, the present invention brings about many direct and indirect effects, and its overall effect is remarkable.

[Brief explanation of the drawing]

1 and 2 are a plan view and a front view of an example of an articulated robot, FIGS. 3 and 4 are sectional views of an embodiment of the joint of an articulated robot according to the present invention and a conventional example, and FIG. 5 is a sectional view taken along the line A-A in FIG. 4; 3...First arm, 5...Second arm, 6...
Joint shafts, 15, 19, 20... Sprockets (part of the driving means for the second arm, wrist, etc.), 17...
...Steel bushing, 23...Flange, 24,60
...Bearing, 26...Boss, 27...Key, 38...
...Natsuto, 40...Boruto.

Claims (1)

[Claims] 1. In a device in which a second arm is rotatably supported by a first arm made of a light alloy via a joint shaft and a bearing provided on the joint shaft, the end of the second arm A hole is bored in each of the branched end parts formed by bifurcating into two parts, and the joint shaft is fixed to only one of the holes by being prevented from rotating through a key, and the joint shaft is A sprocket for driving the second arm, wrist, etc. is attached between the two branch ends, and the other hole of the holes provided in the branch end is larger than the outer diameter of the sprocket. The flange is fitted into the hole and has a joint shaft insertion hole, and the outer peripheral edge thereof is locked to the step. It is fixed with
The bearing insertion hole of the first arm has a diameter larger than the outer diameter of the flange, and the bearing insertion hole rotatably supports the joint shaft through a boss having a bearing and a joint shaft insertion hole. The articulated robot has a structure in which the joint shaft can be disassembled and assembled through the bearing insertion hole and the stepped hole while the sprocket remains fixed to the joint shaft. The structure of the joints.