JPH0260478B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Recently, attempts have been made to horizontally insert and assemble bars with small relative gaps into holes drilled in parts using industrial robots. The relative gap between this hole and the rod is extremely small, ranging from several microns to more than ten microns. On the other hand, the repeatability accuracy of industrial robots is generally about plus or minus 50 microns, which is greater than the relative gap between the hole and the bar. However, making the repeatable position accuracy of an industrial robot smaller than the relative gap between the hole and the bar material would significantly increase the cost of manufacturing the industrial robot, making it uneconomical.

This invention was made in view of the above circumstances, and is particularly designed to absorb the relative misalignment during assembly work by horizontally inserting a bar with a misaligned center into a hole provided horizontally on the side of a component. The present invention provides a simple hand device for an industrial robot that enables insertion and assembly of rods into holes with small gaps.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

In the figure, 1 is the main body of an industrial robot, 2 is an elevating body that is supported by this main body 1 and moves linearly in the vertical direction,
3 is a first arm that is supported by the elevating body 2 and rotates back and forth on a horizontal plane; 4 is a second arm that is supported at the tip of the first arm 3 and rotates back and forth on a horizontal plane; 5 is a tip of the second arm 4; vertical pivot axis, 6
is an L-shaped fitting fixed to the rotation shaft 5, and the horizontal surface 6
a, and a vertical surface 6b. 7 is a misalignment absorbing device fixed to the vertical surface 6b of the L-shaped fitting 6; 7a is the L-shaped fitting 6;
The shaft 7b, which is horizontally planted on the vertical surface 6b of the shaped metal fitting 6, is a core plate fixed to the shaft 7a, and 7b ₁ , 7
b ₂ is a sliding surface, 7c is a case, which includes a disc-shaped upper plate 7c ₁ , a lower plate 7c ₂ and a cylindrical-shaped lower plate 7c 1 whose one side is slidably in contact with the sliding surfaces 7b ₁ and 7b ₂ of the core board 7b. Peripheral wall 7c ₃
It is formed from. 7c ₁₁ is a hole provided in the center of the upper plate 7c ₁ , 7d is an elastic body made of cylindrical rubber or the like that is compressed and inserted between the shaft 7a and the hole 7c ₁₁ and fixed with adhesive, etc., and 8 is the case 7c. A gripping device is fixed to the other side of the lower plate 7c ₂ , and includes gripping claws 8a that are driven by pneumatic pressure or electricity. 9 is a bar gripped by the gripping claws 8a of the gripping device 8; 9a;
10 is a workbench, 11 is a part fixed on the workbench 10, 11a is a hole drilled in the horizontal direction in the part 11, 11b 1 is a mentory portion consisting of an inclined surface provided all around the entrance of the hole 11a.

Here, regarding the characteristics of the elastic body 7d, the second, third,
This will be explained using FIG. The elastic body 7d is the shaft 7a.
The _{upper end side 7d 1 is} further compressed by the weight of the case 7c, the gripping device 8, and the bar 9. On the other hand, the compressive force on the lower end side _7d2 is reduced due to the weight of the case 7c, the gripping device 8, and the bar 9. To explain this using the graph of FIG. 5, the horizontal axis represents the displacement dimension δ of the elastic body 7d, and the vertical axis represents the force P required to displace the elastic body 7d. And point A is the elastic body 7
If d is the zero point when set, then in this case the elastic body 7d is compressed from point B to point A over the entire circumference, and has a compressive force of _p1 in every direction. However, as mentioned above, due to the influence of the case 7c, the gripping device 8, and the bar 9, the compressive force on the upper end side _7d1 of the elastic body 7d has increased to point _P2 , and conversely, the compressive force on the lower end side _7d2 has increased.
P It has decreased to ₃ points. In _addition , the relative displacement between the core plate 7b and the case 7c is determined by the misalignment between the bar 9 and the hole 11a in the set state (the state in which the gripping device 8 is gripping the bar 9) so that the P3 point is always greater than zero. The compression dimension and spring constant of the elastic body 7d are appropriately determined so as not to exceed a preset allowable range.

That is, when the bar 9 is positioned above the hole 11a, the bar 9 is pushed downward by a force of P2 _or more and inserted into the hole 11a. Conversely, when the bar 9 is positioned below the hole 11a, the bar 9 is pushed upward by the force at point _P3 and inserted into the hole 11a. In addition, the left and right direction is not affected by the weight of the case 7c, the gripping device 8, and the bar 9, so if the bar 9 is shifted in the left and right direction with respect to the hole 11a, the bar 9 is
P It is pushed in the right and left direction with a force of _one point and is inserted into the hole 11a. In either case, the elastic body 7d is displaced only by the misalignment dimension between the bar 9 and the hole 11a, and the force pushing the bar 8 due to the displacement is pulled upward to the right from points _P1 , _P2, and _P3 . It rises along the drawn line.

Next, a state in which the misaligned rod 9 is inserted into the hole 11a will be described. Now, by controlling the elevating body 2 and the first and second arms 3, 4, as shown in FIG.
Even if the center of the bar 9 is at a position shifted by δ ₁ , this misalignment dimension is
If the total size is less than the total size, if the bar 9 is inserted into the hole 11a by controlling the first and second arms 3, 4 and the rotation axis, the elastic body 7d will be deformed as shown in FIG. The rod 9 automatically aligns with the center of the hole 11a to perform insertion and assembly operations. At this time, an upward force of _two points P' is acting on the bar 9.

In general, the mently dimensions of the mently parts 9a and 11b are 0.5 to 1.0 mm, which is large enough for the repeatable position accuracy of an industrial robot. Therefore, even if the industrial robot has a repeatable position accuracy of about plus or minus 50 microns, the misalignment absorbing device 7 can be used. By using this, the work of inserting and assembling the rod 9 and the hole 11a with a small relative gap can be performed reliably.

In the above embodiment, the bar 9 is located below the hole 11a, but the same effect can be obtained no matter where the bar 9 is located. However, bar material 9
The core of the bar 9 is always slightly lower than the core of the hole 11a in order to make the insertion work easier and more reliable by reducing the lateral force applied to the hole 11a, and to extend the life of each component. It is desirable to control the elevating body 2 so that it is in the correct position.

Furthermore, since the compression dimension and spring constant of the elastic body 7d are selected so that relative displacement between the core board 7b and the case 7c does not occur when the bar 9 is set in the gripping claw 8a, the elevating body 2 can be easily controlled.

Further, although the above embodiment shows the case where the hole and the rod are completely horizontal, the same effect can be obtained even if the hole and the rod are slightly inclined.

Furthermore, if the elastic body 7d is made of foamed rubber or has a partially hollow space, the spring constant can be freely selected, the design of the misalignment absorbing device 7 becomes easier, and the distance between the bar 9 and the hole 11a is increased. It is also possible to freely determine the increasing force in the lateral direction that is applied to the bar 9 when the misalignment dimension is absorbed.

As explained above, the hand device for an industrial robot according to the present invention includes: a robot arm that is vertically movable and horizontally rotatable; a core board, a case that surrounds the core board and has a hole through which the shaft is inserted and is slidable in the vertical direction relative to the core board, and between the shaft of the core board and the hole in the case; a misalignment absorbing device made of an elastic body in a compressed state; and a gripping device fixed to the case and having gripping claws for horizontally gripping a bar inserted into the hole formed in the horizontal direction; and; A mentory part is provided at a facing portion of at least one of the bar material and the insertion hole of the bar material, and the robot arm is controlled to move up and down to move the bar material into the insertion hole of the bar material in the mentry part. and a control device for controlling the insertion of the bar material into the insertion hole; and; Since the bars are placed opposite each other and then the bar is inserted into the insertion hole, the lateral force applied to the bar is reduced, and the bar can be inserted into the hole with little force, making the insertion process easier and more reliable. , the life of each component can be extended, and since the gripping device slides against the core board together with the case, the bar only moves in parallel and does not tilt, so it is possible to use a bar with a small relative distance. It has the effect of being suitable for inserting materials into holes.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of a hand device for an industrial robot according to the present invention, and FIG. 2 is an enlarged view of a portion of FIG. 1, with a part thereof shown in cross section. Figure 3 is a sectional view taken along the - line in Figure 2, Figure 4 is an operation diagram showing the operating status of the misalignment absorbing device when absorbing misalignment between the bar and the hole, and Figure 5 shows the characteristics of the elastic body. This is a graph showing. 1...Industrial robot main body, 2...Elevating body, 3, 4
...First and second arms, 5... Rotation shaft, 7... Misalignment absorber, 7a... Shaft, 7b... Core board, 7c... Case, 7
d...Elastic body, _7d1 ...upper end, _7d2 ...lower end, 8...
Gripping device, 9...bar, 9a...mentory part, 11...
Parts, 11a...hole, 11b...mentory part.

Claims (1)

[Scope of Claims] 1. A robot arm that is vertically movable and horizontally rotatable; a core board that is attached to the tip of the robot arm in the vertical direction via a shaft, through which the shaft is inserted; a case that surrounds the core board and is slidable relative to the core board in the vertical direction; and an elastic case in a compressed state that is disposed between the axis of the core board and the hole in the case. a misalignment absorbing device consisting of a body; a gripping device fixed to the case and having gripping claws for horizontally gripping a bar to be inserted into a hole formed in the horizontal direction; and the bar and the bar. A mentory part is provided in an opposing part of at least one of the insertion holes of the rod, and the robot arm is controlled to move up and down to place the bar material below the insertion hole of the bar within the dimension of the mentory part. , and then a control device for controlling the insertion of the bar into the insertion hole; and a hand device for an industrial robot. 2. The hand device for an industrial robot according to claim 1, wherein the elastic body is made of annular rubber. 3. The hand device for an industrial robot according to claim 1, wherein the elastic body has a hollow space inside.