DE3022162A1 - Rotary actuator with motion limiting for industrial robot - has actuator fluid supplied through swivel with limiting flow restrictor - Google Patents

Abstract

The industrial robot using rotary hydraulic actuators includes a facility to limit and control the stopping action. Each rotary motion has a shaft (8) that rotates within a sleeve (9) with a large clearance volume (12). Hydraulic fluid is passed through a supply time (13) and exits through a bore (15) in the central shaft. The fluid is used to supply the hydraulic drive motor. A projecting segment (16) is located to control the angle of operation of the actuator when the outlet (14) passes via the small clearance (18) the flow is reduced and the actuator slows down.

Description

The invention relates to a device on industrial

robots to limit the swivel range of arm parts with the Features of the preamble of claim 1.

It is well known that hydraulic rotary actuators are developing for industrial robots very high torques for larger designs.

On the one hand, these torques are desirable because they make the structure extraordinary more efficient systems. On the other hand, however, precautions must also be taken to safely prevent erroneous movement into a forbidden area.

Have industrial robots of known design - regardless of the Type of drive - fixed end stops to prevent such erroneous movements, which are often designed as stop buffers (example: KUKA company brochure SK 37-015-32).

End stops of this type can in part also be arranged in such a way that that they z. B. the rotation of an industrial robot arm around the vertical central axis allow only in a desired, limited area, with which the adaptation of the Robot is facilitated to a given application.

A hydraulic swivel drive with a very high output torque (e.g. 20,000 Nm and more) requires a very heavy one for such a solution Stop and appropriate fasteners. Further effort would be required if this stop is to be designed so that it is suitable for a given application can be adjusted by offsetting. It is therefore the object of the invention to this To avoid disadvantages in the industrial robots in question, that is, for it Care must be taken that when pivoting over a predetermined, harmless area in addition, neither internal damage occurs nor external equipment, machine parts, Superstructures or even people are endangered. The design should be cheap and be simple, can be easily adapted to the respective requirements and without additional installation space can be realized. It should also make it possible to put electrical or electronic signaling devices into operation without destroying them to fear.

This object is achieved according to the invention with the features of the characterizing part of claim 1.

This solution has the advantage of extraordinary simplicity and Reliability. Even commercially available rotating unions can be easily provided with a locking member according to the invention.

In the case of hydraulic cylinders moving in a translatory manner, so-called End position damping known in a variety of embodiments. This end position cushioning however, are generally not adjustable depending on the stroke and beyond that Slew drives can only be transferred with great difficulty or not at all. The application of so-called Braking or deceleration valves would be conceivable in principle, but would be added in addition to the expense for the valve itself, there is also one for one in different angular positions effective fastening and cable routing.

Claims 2 to 4 relate to various arrangements and Refinements of the closing element.

The claims 5 to 8 are directed to additional electrical or electronic signaling devices.

The invention is based on an embodiment shown in the figures explained in more detail, with the processing of the signals or signal generators in a block diagram is pictured.

Figure 1 shows a schematic of an industrial robot with linked Swivel joints.

Figure 2 shows a section of a rotary union with the drain assigned ring channel.

Figure 3 shows a section corresponding to that given in Figure 2 Cutting line.

Figure 4 shows a section corresponding to Figure 3 with the Closing member in engagement.

Figure 5 shows a block diagram for processing the End position monitoring resulting signals as well as for manual resetting.

An industrial robot 1 has several axes 2, 3 and 4 with associated, swivel motors not shown in detail. The hydraulic supply of the swivel motors takes place via hydraulic rotary feedthroughs, which has the advantage that fixed pipelines on the arm parts 5 or 6 between the axes 2 and 3 or 3 and 4 can be relocated. A rotary feedthrough 7 is shown in detail in Figure 2 shown and has a first part 8 of cylindrical cross-section, which is guided in a corresponding bore of a second part 9. In part 9 are with an axial distance between two seals 10 and 11, between which a Annular channel 12 is located, in which an opening 13 opens within the part 9.

In the part 8 is the annular channel 12 opposite an opening 14, which propagates to a longitudinal bore 15 in part 8. A closing member protrudes into the annular channel 12 16 into it, which can be fastened with the aid of a clamping screw 17. Even if the closing member 16 has completely covered the opening 14, a designated 18 remains Minimum flow area. The permitted swivel range is denoted by 19. Within the area designated by 20, the locking member 16 is fully engaged.

To explain the function, it is assumed that Figures 3 and 4 it is assumed that the swivel motor, not shown, is starting operated by the central position shown in Figure 3 and the ring channel 12 serve to drain the pressure medium. According to the movements of the swing motor a relative movement will then take place between parts 8 and 9, that is, the striker approaches the opening 14 without, however, initially becoming effective.

Eventually, however, the opening 14 begins to close.

Since the flow cross-section is in one of the shape of the Opening 14 and the shape of the closing member 16 is reduced depending on the manner, A steadily increasing counter pressure builds up in the process, and so does the speed of the swivel motor is steadily lower. It is at the discretion of the designer how small the minimum flow cross section 18 can be. In any case it is strive to decelerate the swivel motor until it reaches creep speed, because at such a low speed there is a risk of destruction or damage is already greatly reduced and with the help of other measures such. B. an emergency stop circuit can be effected.

Such a measure can, for. B. caused by approaching limit switches will. The function of such an end position monitoring can be seen in Figure 5.

For axis 2 shown as an example, there is ongoing monitoring compliance with the permitted swivel range 19 z. B. by a not shown, with the swivel drive connected cam, which is also not shown Limit switch (A) in (and only in) the permitted swivel range 19 keeps activated, in connection with one limit switch each - not shown - on the left (L) and on the right (R) Limitation of the permitted swivel range 19. As soon as the limit switch (A) the exit from the permitted swivel range 19 is registered, the control takes place the EMERGENCY STOP device for the entire industrial robot, either (with End position L) via the limit switch (L) with memory function, or (with end position R) via the limit switch (R) with memory function, or, if the relevant limit switch (L) or (R) fails over a logical link unit, which at the same time The 3 conditions are met - Part-turn actuator outside the permitted range - End position L not registered - End position R not registered also triggers an EMERGENCY STOP. In this latter case there is a malfunction caused by the normal reset routine cannot and should not be eliminated.

The EMERGENCY STOP control of the industrial robot makes all axes blocked both in the direction of rotation L and in the direction of rotation R and the industrial robot stands.

Only through manual actuation of the respective end position approach movement Reset button T1 or T2 in the opposite direction of rotation is a reset causes from the end position, at the same time - regardless of the invention hydraulic device - the control is switched to creep gear. As soon the logical linkage conditions - end position L (or R) - reset command - creep speed - Direction of rotation R (or L) are present at the same time, then according to the invention, the Actuation of the swivel drive 2 for the return movement in creep speed in the direction of rotation R (or L) with simultaneous unblocking of the direction of rotation R (or L) only for this axis.

With the return movement, when the permitted Swivel range of the limit switch (A) is activated again and the end position limit switch L (or R) deactivated again, whereby the control of the EMERGENCY STOP device is canceled and the industrial robot again with all axes and for all directions of rotation every axis is functional.

L e r s e i t e

Claims (8)

Designation: Equipment on industrial robots to limit the swivel range of arm parts Patent claims: 1. Device on industrial robots for limiting the swivel range of arm parts, which are operated with the aid of a swivel motor or the like are pivotable about an axis and in which the supply of pressure medium to the or the discharge of pressure medium from the working spaces via a hollow shaft or the like and a hydraulic rotary feedthrough, which is at least two of two relatively rotatable parts formed and against each other and the environment has sealed annular channels, in each of which one in the one part and one Openings in the other part serving to convey the pressure medium open out, characterized in that on one of the parts (9) into an annular channel (12) protruding, and after a predetermined pivoting range (19) the opening (14) in the other part (8) increasingly locking closing element (16) arranged is. 2. Device according to claim 1, characterized in that the closing member (16) is shaped so that the flow cross-section remaining with increasing blocking corresponds to a predetermined function based on the pivot angle. 3. Device according to claim 1 or 2, characterized in that A minimum flow cross-section (18) is always available regardless of the swivel angle is. 4. Device according to one or more of the preceding claims, characterized characterized in that in each case the opening assigned to the discharge of the pressure medium (14) is blocked by the closing element (16). 5. Device according to one or more of the preceding claims, characterized characterized in that according to a predetermined pivot angle after it takes effect of the locking member (16) an electrical or electronic signal transmitter from the Arm part is operated, which signal transmitter directly or with the involvement of a Program causes an emergency stop. 6. Device according to claim 5, characterized in that the emergency stop circuit applies equally to other axes of the industrial robot. 7. Device according to claim 5 or 6, characterized in that the emergency stop circuit can only be canceled if a reset command with the opposite Direction is given. 8. Device according to claim 7, characterized in that the reset command all other axes are blocked.