WO2019012685A1

WO2019012685A1 - Workpiece-attitude-discernment mechanism for robot chuck

Info

Publication number: WO2019012685A1
Application number: PCT/JP2017/025683
Authority: WO
Inventors: 加藤正樹
Original assignee: 株式会社Ｆｕｊｉ
Priority date: 2017-07-14
Filing date: 2017-07-14
Publication date: 2019-01-17
Also published as: JP6768159B2; JPWO2019012685A1

Abstract

A workpiece-attitude-discernment mechanism for a robot chuck, said mechanism discerning the attitude of a workpiece held by the robot chuck, and comprising: multiple assembly holes provided in a chuck part of a robot chuck that holds a workpiece via multiple chuck jaws; an airflow passage that supplies air to the assembly holes; multiple pushers that are respectively and independently inserted into the assembly holes such that the pushers are capable of moving in the pressing direction of the workpiece, and that are independently switched, according to the extent of the pressing by the workpiece, between a state in which the air is released to the atmosphere, and a state in which the air is isolated from the atmosphere; and an air-pressure-detection unit that detects the pressure of the air within the airflow passage.

Description

Work posture determination mechanism of robot chuck

The present invention relates to a work posture determination mechanism of a robot chuck capable of detecting a gripping state regarding a posture of a work.

For example, when processing a work by a plurality of machine tools, an automatic loader for carrying the work is used in order to automatically transfer the work with the machine tool. A chuck is provided in a machine tool or an autoloader, and the work is delivered by gripping the other chucks. Patent Document 1 below discloses a loader with a workpiece inclination detection function that detects the inclination of a workpiece held by a loader chuck. If an inclination occurs in the posture of the workpiece, machining defects occur. Therefore, the inclination of the workpiece can be detected before machining.

In the loader described in the same document, when the held workpiece is inclined, the pusher plate in contact with the seated work also has an inclination, and the inclination can be detected by the detector. A detection structure for that purpose is provided with a plurality of pushers biased so that the tip contacts the pusher plate, and the inclination of the work end surface is detected by measuring the position of the plurality of pushers movable in the biasing direction. It can be done. Specifically, the detection signal of the displacement sensor is transmitted to a computer or the like through the signal cable, and the detection value comparison means detects the inclination of the pusher plate, that is, the inclination of the workpiece held by the loader chuck.

International Publication WO2013 / 031375

The loader chuck equipped with the work inclination detection function enters the processing room of the machine tool and delivers the work, but chips and coolant of the work are scattered in the processing room where the delivery is performed. It is an environment. Therefore, in the conventional loader chuck, since the displacement sensor is provided in the vicinity of the working unit for gripping the workpiece, chips and the like may be attached to the displacement sensor in the processing chamber. That is, in the conventional structure, it is conceivable that accurate detection by the displacement sensor is hindered. Further, the above-described loader chucks are provided in a gantry type drive mechanism installed above the machine tool, and two units are attached to the loader heads movable in the left-right direction, the front-rear direction and the up-down direction There is. The two loader chucks are each capable of rotating 180 °. That is, in the conventional tilt detection mechanism through the signal cable of the displacement sensor, the rotation of the loader chuck is limited by the signal cable.

The work posture determination mechanism for a robot chuck according to one aspect of the present invention includes a plurality of assembly holes provided in a chuck portion of the robot chuck that holds a workpiece with a plurality of chuck claws, and air for supplying air to the plurality of assembly holes. A flow path and each independently inserted in the plurality of assembly holes in a movable state in the pressing direction by the work, and depending on the pressing amount of the work, the air is released to the atmosphere and blocked. A plurality of pushers to be switched and an air pressure detector for detecting the pressure of the air in the air flow path are included.

According to the above configuration, air is fed to the assembly hole of the robot chuck into which the plurality of pushers are inserted, via the air flow path. In such a state, the work is gripped by the plurality of chuck claws of the robot chuck. At this time, the pusher is pushed and displaced by the work, and the release of air sent into the assembly hole to the atmosphere and the shut off are switched. Be Therefore, the pressure of the air in the air flow path changes, and the air pressure detector detects it, whereby the posture of the workpiece held by the robot chuck can be determined.

It is a side view showing an articulated robot arm. It is an external appearance perspective view showing a robot chuck. It is the simplification figure which showed the work posture distinction mechanism. It is a cross-sectional perspective view of a robot body. It is a cross section of the work posture determination unit. It is an external appearance side view showing a pusher. It is an appearance perspective view showing a pusher. It is an external appearance side view showing a pusher.

Next, an embodiment of a work posture determination mechanism for a robot chuck according to the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing an articulated robot arm. In the present embodiment, the workpiece posture determination mechanism of the robot chuck incorporated in the articulated robot arm will be described as an example. Therefore, first, the articulated robot arm will be briefly described. The articulated robot arm 1 is provided in a processing machine line in which a plurality of machine tools are arranged, and constitutes an autoloader for automatically delivering and receiving a work with each machine tool. Therefore, the articulated robot arm 1 is mounted on the carriage 2 via the turning mechanism, and is configured to be movable in the direction through the drawing.

In the articulated robot arm 1, the upper arm member 12 is connected to the pivotable support 11 via the first joint mechanism 14, and the forearm member 13 further connects the second joint mechanism 15 to the upper arm member 12. It is linked through. When traveling between machine tools, the articulated robot arm 1 overlaps the upper arm member 12 and the forearm member 13 in a standing state as illustrated. On the other hand, when transferring work with the machine tool, the upper arm member 12 and the forearm member 13 are rotated by the first joint mechanism 14 and the second joint mechanism 15, and the right side of the drawing faces the front of the machine tool An extended operation is performed.

A robot chuck 3 capable of gripping a workpiece is attached to the end of the articulated robot arm 1, that is, the end of the forearm member 13. In addition, the articulated robot arm 1 is provided with a reversing device 4 for changing the direction of the workpiece on the rear side, so that the workpiece can be delivered between the robot chuck 3 and the reversing device 4 . In the reversing device 4, the workpiece which has been reversed by 180 ° can be delivered to the robot chuck 3. The robot chuck 3 is assembled to the forearm member 13 with a rotation axis in a direction passing through the drawing in order to deliver and receive a work between the spindle chuck of the machine tool and the reversing device 4.

FIG. 2 is an external perspective view showing the robot chuck 3. The robot chuck 3 has a first clamp surface on the front side of the drawing and a second clamp surface on the back side of the robot main body 25 so that the workpiece can be gripped on both sides. That is, three chuck slides 21 arranged radially are provided on the clamp surfaces on both sides, and chuck claws 22 (see FIG. 3) are attached to the chuck slides 21. The three chuck claws 22 are disposed at an interval of 120 °, and are configured to reciprocate linearly in synchronization in the radial direction. Accordingly, movement of the chuck jaws 22 toward the center enables clamping of the work, and movement of the chuck claws 22 outward causes amplification of the work.

The robot chuck 3 is integrally configured with a coaxial bearing member 26 so as to sandwich the robot body 25. It is rotatably assembled to the forearm member 13 of the articulated robot arm 1 via the bearing member 26. A drive motor is attached to the articulated robot arm 1 side, and a belt is stretched between the rotary shaft and the pulley 27 on the robot chuck 3 side. Therefore, the drive control for the drive motor makes it possible to adjust the angle of the first clamp surface or the second clamp surface of the robot chuck 3 when transferring a work with a machine tool or the like.

The robot chuck 3 has a clamp mechanism configured to operate the chuck slide 21 in the robot body 25 in order to clamp and unclamp a workpiece. In particular, this clamp mechanism is operated by hydraulic pressure, and is configured to supply and discharge hydraulic oil with a hydraulic pump and a tank installed outside the articulated robot arm 1. Therefore, in the robot chuck 3, a hydraulic circuit that controls the operation of the chuck slide 21 is configured inside the bearing member 26. The robot chuck 3 is thus configured such that the hydraulic fluid, which is fluid, flows between the robot chuck 3 and the outside, but in addition, air for the work posture determination mechanism described below is also fed. .

FIG. 3 is a simplified view showing a work posture determination mechanism. Only the robot body 25 of the robot chuck 3 is shown in the drawing. An air flow path is formed in the robot body 25 so that air can be supplied through the bearing member 26 in the same manner as the hydraulic oil. An air compressor 31 installed outside the articulated robot arm 1 is connected to the robot chuck 3 via an air pipe 32. The air compressor 31 supplies air at a predetermined pressure, and the air pipe 32 is provided with a pressure switch 33 for detecting the air pressure in the flow path. The articulated robot arm 1 is provided with a control device 8 for performing drive control of each drive including the robot chuck 3. The pressure switch 33 is connected to the controller 8 via the signal cable 35.

The robot chuck 3 is configured with a workpiece posture determination unit for determining the posture of the workpiece at the time of clamping by air. The robot chuck 3 has chuck claws 22 at equal intervals as shown in FIG. 3, and three work posture determination units 36 are provided at equal intervals so as to be positioned therebetween. The robot body 25 is formed with a single air supply passage 37 communicating with all three work posture determination units 36, and an air pipe 32 is connected thereto to form a series of air passages. The work posture determination unit 36 is provided on both sides of the first clamp surface and the second clamp surface, and as shown in FIG. 2, a pusher 41 in contact with the work is protruded from the surface side. In addition, since a 1st clamp surface and a 2nd clamp surface are comprised similarly, below, it is demonstrated as the clamp surface 251, without distinguishing.

Here, FIG. 4 is a cross-sectional perspective view of the robot main body 25, and FIG. 5 is a cross-sectional portion of the work posture determination unit 36. The work posture determination unit 36 has three assembly holes 42 in a direction orthogonal to the clamp surface 251 with respect to the robot body 25, and one air supply flow path 37 is connected to all of the assembly holes 42. Pushers 41 are inserted into the three assembly holes 42 respectively. The pusher 41 has a flange portion 412 formed on the open end side of the bottomed cylindrical main body portion 411, and the closed tip end side protrudes from the robot main body 25 and the tip surface in contact with the workpiece W is spherical It has become.

The mounting hole 42 has a square shape as shown in FIG. 3, and a flange portion 412 which spreads in three directions is loosely fitted therein. The flange portion 412 is for restraining the pusher 41 in the assembly hole 42 so that the cylindrical main body portion 411 is not displaced in the circumferential direction. Further, although the lid member 43 is attached to the assembly hole 42, the flange portion 412 also plays a function to prevent the pusher 41 from falling off by being caught by the lid member 43. A guide hole 431 is bored in the central portion of the lid member 43, and the pusher 41 penetrates the guide hole 431 in a slidable state. Therefore, the pusher 41 can move in the direction along the center line 40 while maintaining its posture without rotating in the circumferential direction.

In the work posture determination unit 36, a spring 45 is inserted into the space 46 in the assembly hole 42, in particular, in the pusher. Therefore, the pusher 41 is always biased by the spring 45 in the direction in which the end of the main body 411 protrudes from the assembly hole 42. Further, although the air supply channel 37 shown in FIG. 3 is not shown in detail in FIGS. 4 and 5, the air fed into the air supply channel 37 is particularly a pusher in the assembly hole 42 as shown by the arrow. It will be blown into the inner space 46. Therefore, the pusher 41 is shown pressed into the assembly hole 42 by the work W in FIG. 5, and the tip of the main body 411 protrudes up to the position indicated by the alternate long and short dash line under normal conditions.

FIG. 6 is an external side view showing the pusher 41. As shown in FIG. The pusher 41 has a lateral hole 415 formed on the side surface of the main body 411 for drawing out the air of the inner space 46 of the pusher. An oblong leak recess 416 is formed on the side surface of the main body 411 of the pusher 41 so that the longitudinal direction thereof is along the center line 40 of the pusher 41. The lateral hole 415 is formed to be located on the flange portion 412 side in the leakage recess 416. Therefore, as shown in FIG. 5, the portion of the recess for leakage 416 is lower than the other side portion, and the recess for leakage 416 forms a gap with the inner circumferential surface of the guide hole 431.

A leak hole 432 is bored in the lid member 43 in the direction orthogonal to the guide hole 431. The pusher 41 is assembled such that the displacement in the circumferential direction is restrained by the shapes of the flange portion 412 and the assembling hole 42, and the leakage recess 416 is aligned with the position of the leakage hole 432. Therefore, when the pusher 41 moves in the assembly hole 42 along the center line 40, the leak recess 416 always passes through a position overlapping the leak hole 432.

Subsequently, the operation of the workpiece posture determination mechanism of the robot chuck 3 will be described. First, the articulated robot arm 1 moves the robot chuck 3 at the tip to a predetermined position by the expansion and contraction operation of the upper arm member 12 and the forearm member 13 by driving the first joint mechanism 14 and the second joint mechanism 15. . The robot chuck 3 adjusts the angle of the clamp surface 251 of the robot body 25 via the bearing member 26. In the robot chuck 3 facing the work W, the chuck claws 22 are actuated by the supply and discharge of the hydraulic oil, and the work W is clamped or unclamped. The robot chuck 3 for clamping the workpiece W moves with the clamping surface 251 side maintaining a predetermined angle, and the tip of the pusher 41 is pressed against the workpiece W as shown in FIG.

Therefore, although the pusher 41 pressed against the work W enters the assembly hole 42, the pusher 41 in the normal time is always subjected to the biasing force of the spring 45 and protrudes to the position shown by the dashed dotted line in FIG. ing. In that case, the leakage concave portion 416 and the leakage hole 432 are in an overlapping positional relationship as indicated by a one-dot chain line in FIG. The air is always fed into the work posture determination unit 36, but the air blown into the space 46 in the pusher normally leaks from the lateral hole 415 in the normal state where the leakage concave portion 416 and the leakage hole 432 overlap. It is released to the atmosphere.

The pressure of air being sent to the robot chuck 3 is detected by the pressure switch 33 of the air pipe 32. When the robot chuck 3 is in the unclamped state, the supplied air is discharged to the atmosphere, so the pressure switch 22 normally detects a value lower than a predetermined threshold. On the other hand, when clamping the work W by the robot chuck 3, the pusher 41 against which the work W is pressed is pushed into the operation hole 42 against the biasing force of the spring 45 and moves to the position shown in FIG. It becomes. That is, as shown in FIG. 5 and FIG. 6, the recess for leakage 416 deviates from the position of the leakage hole 432, and the space 46 inside the pusher is shut off from the atmosphere.

At this time, with regard to the three work posture determination units 36 in the clamp surface 251, if all the pusher inner spaces 46 are shut off with the leak holes 432, the flow of air sent from the compressor 31 to the air piping 32. Will be almost stopped. Therefore, the pressure in the air piping 32 exceeds a predetermined threshold, and a detection signal is transmitted to the control device 8 from the pressure switch 33 which has detected the state. Then, in the control device 8 that has received the detection signal, the clamp state is also confirmed, and if appropriate, the next drive control instruction is issued. However, if at least one of the three work posture determination units 36 releases air to the atmosphere without the pusher 41 being pushed to a predetermined position, the pressure in the air pipe 32 is lower than a predetermined threshold value. It remains.

For example, if the clamp surface 251 of the robot chuck 3 is inclined with respect to the workpiece W, a state may occur in which any one of the pushers 41 is not pushed into the home position. Therefore, air is continuously released to the atmosphere in the corresponding work posture determination unit 36, and the pressure in the air piping 32 remains low. In such a case, even if the workpiece W can be clamped, the workpiece W can not be properly delivered to the mating chuck, and the workpiece W in the process of being transported may collide with the inside of the machine tool. It can occur. Therefore, in the present embodiment, when a detection signal is not received from the pressure switch 33 when the clamp state of the work W is detected, the control device 8 determines that a clamp error occurs, and the work W is removed from the processing line. It will be beaten.

Therefore, in the work posture determination mechanism of the present embodiment, air is sent from the outside to the robot chuck 3 like the hydraulic oil, and the posture of the work W can be determined by detecting the air pressure. Therefore, the rotational movement of the robot main body 25 is not restricted without the signal cable being drawn around the robot chuck 3. Moreover, since the air pressure change accompanying the mechanical operation of the pusher 41 is detected outside and the posture determination is performed based on it, the work posture determination mechanism is used even for the robot chuck 3 used in the machine tool. Very unlikely to be affected by chips and coolant.

Further, since the work posture determination unit 36 has a compact configuration, it is suitable for a small-sized robot chuck 3 or the like used for the articulated robot 1. Furthermore, in the present embodiment, by sending air to one air supply flow path 37 communicating with the three work posture determination units 36, the posture of the work W is not even at one position if the push-in position of the pusher 41 is not appropriate. It can be confirmed that it is not correct. Therefore, the work posture determination mechanism can be configured simply to detect the internal pressure of the air pipe 32 by the pressure switch 33.

By the way, in the pusher 41, a recess for leakage 416 is formed so as to overlap the lateral hole 415. Accordingly, when the leakage recess 416 and the leakage hole 432 overlap, the air passes from the lateral hole 415 to the leakage hole 432 and is released to the atmosphere. Since the leak recess 416 is formed relatively large, as shown in FIG. 5, when the pusher 41 is pushed deep into the assembly hole 42, the release of air is blocked. That is, the robot chuck 3 holds the workpiece W deeply by the chuck claws 22.

On the other hand, the workpiece W may be gripped by the chuck claws 22 so as to be shallow. The work posture determination unit 36 is configured to be able to adjust how to grip the work W by replacing the pusher 41. Here, FIG. 7 is an external perspective view showing the pusher 41, and FIG. 8 is an external side view showing the pusher 41. As shown in FIG. As described above, the pusher 41 is formed with the flange portion 412 which is expanded in three directions, and has a hexagonal shape in which the small side surface 412 a and the large side surface 412 b are alternately and uniformly arranged in the circumferential direction. And, according to the position of the one major side 412b, the horizontal hole 415 and the recess for leakage 416 are formed.

In the pusher 41, lateral holes 415 are also formed on the other two large side surfaces 412b, and different leak

concave portions

417 and 418 are formed in each of them. Although leak recessed

parts

416 and 417 are shown in FIG. 7, both have an oval shape having different lengths in the direction along the center line 40. The three lateral holes 415 formed in the pusher 41 have the same position in the direction of the center line 40 and are formed at equal intervals in the circumferential direction of the main body 411. Further, the leakage recesses 416, 417, 418 formed in the respective horizontal holes 415 are different in size as shown in FIG. In FIG. 8, the concave portions for

leakage

417 and 418 are shown by being superimposed by dashed dotted lines at the position of the concave portion for leakage 416. As can be seen from this figure, the difference in the size of the leakage recesses 416, 417, 418 is the difference in the distance to the leakage hole 432.

The pusher 41 can incorporate three patterns in which the direction of the flange 412 is changed in the square-shaped assembling hole 42. That is, any one of the leakage recesses 416, 417 and 418 can be matched with the leakage hole 432 of the lid member 43 as desired. Therefore, as shown in FIG. 8, the pusher 41 having the tip at the position indicated by the alternate long and short dash line in normal times is pushed and displaced in the direction indicated by the arrow when the robot chuck 3 grasps the work W. At this time, in the case of the smallest leak recess 418, the lateral hole 415 is shut off with the leak hole 432 with a slight displacement. Then, the lateral recess 415 is blocked between the leak recess 418 and the leak hole 432 with a larger displacement, and in the case of the leak recess 416, the pusher 41 is displaced the most before the cutoff.

Therefore, when detecting the work posture determination, it is possible to adjust the displacement amount of the pusher 41, that is, the gripping depth of the work W by the chuck claws 22. Since the depth at which the workpiece W is gripped is controlled in advance by the drive control of the articulated robot arm 1, teaching is performed in advance, but, for example, input of a numerical value obtained based on a detection signal of the pressure switch 33 is performed.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to these, A various change is possible in the range which does not deviate from the meaning.
For example, since the robot chuck is an example, the present invention can be practiced with robot chucks having other structures.
Further, for example, in the embodiment, the work posture determination unit 36 is provided at three locations of the robot main body 25. However, depending on the case, two locations or four locations may be used.
Further, for example, although the pusher 41 of the embodiment has a circular cross section of the main body 411, it may be a square fitted to the shape of the assembly hole 42.

DESCRIPTION OF SYMBOLS 1 ... Articulated robot arm 3 ... Robot chuck 8 ... Control device 21 ... Chuck slide 22 ... Chuck nail 25 ... Robot main body 26 ... Bearing member 31 ... Air compressor 32 ... Air piping 33 ... Pressure switch 35 ... Signal cable 36 ... Work posture Discrimination unit 41 ... pusher 42 ... assembly hole 43 ... lid member 45 ... spring 46 ... space inside pusher 415 ... lateral hole 416 ... recess for leakage 431 ... guide hole 432 ... leakage hole

Claims

A plurality of assembling holes provided in a chuck portion of a robot chuck that holds a work by a plurality of chuck claws;
An air flow path for supplying air to the plurality of assembly holes;
Each is independently inserted into the plurality of assembly holes in a movable state in the pressing direction by the work, and is switched between the release state of the air to the atmosphere and the blocking state according to the pressing amount of the work. A pusher,
An air pressure detector configured to detect the pressure of the air in the air flow path;
The pusher is a member in which a lateral hole is formed in a side of a bottomed cylindrical shape, and the bottomed portion side is protruded so as to be inserted into the assembly hole.
A biasing member is incorporated into the assembly hole to bias the pusher in a direction to project it;
The work of the robot chuck according to claim 1, wherein the air sent into the inside of the pusher can be switched between release to the atmosphere through the lateral hole and blocking depending on the position of the pusher with respect to the assembling hole. Posture discrimination mechanism.
A lid member having a guide hole for guiding the movement of the pusher is fitted into the opening of the assembly hole, and a lateral hole of the pusher overlaps the lid member to form a leak hole for discharging the air to the atmosphere. A work posture determination mechanism for a robot chuck according to claim 2.
The pusher has a plurality of lateral holes formed circumferentially in the side portion, and a recess for leakage which differs in size from the lateral hole to the bottom portion side with respect to each of the lateral holes is formed in the outer peripheral surface A work posture determination mechanism for a robot chuck according to claim 3.
5. The work posture determination mechanism for a robot chuck according to claim 4, wherein the pusher positions any one of the plurality of lateral holes with respect to the leak hole and inserts the lateral hole into the assembly hole.
The robot according to any one of claims 1 to 5, wherein the air flow passage in the robot body portion is formed with one air flow passage connected to all of the plurality of assembly holes. Chuck's work posture determination mechanism.