WO2018092180A1

WO2018092180A1 - Chuck device for robot hand of arm robot

Info

Publication number: WO2018092180A1
Application number: PCT/JP2016/083744
Authority: WO
Inventors: 水田賢治
Original assignee: 株式会社Ｆｕｊｉ
Priority date: 2016-11-15
Filing date: 2016-11-15
Publication date: 2018-05-24
Also published as: JPWO2018092180A1; JP6661026B2

Abstract

A chuck device for a robot hand of an arm robot comprising: a cylinder body (41) in which an extension-side port and a contraction-side port for supplying and discharging hydraulic oil are formed; a piston (42) with attached rod, which is inserted in the cylinder body so that the rod portion protrudes and which is displaced by oil pressure in a pair of pressure chambers that are in communication with the extension-side port or the contraction-side port; a pressure-maintaining cylinder wherein the piston with attached rod serves as the pressure-maintaining cylinder body, a pressure-maintaining piston is inserted therein, and the pressure-maintaining piston is displaced toward the leading end of the rod portion by oil pressure in a pressure-maintaining pressure chamber that is in communication with pressure-maintaining ports formed in the pressure-maintaining cylinder body; a biasing member placed in a leading end space inside the pressure-maintaining cylinder body so as to bias the pressure-maintaining piston towards the pressure-maintaining pressure chamber; and a chuck mechanism, which is connected to the rod portion protruding from the cylinder and which opens and closes multiple chuck jaws by the displacement of the piston with attached rod.

Description

Chuck device for robot hand of arm robot

The present invention relates to a chuck device for a robot hand incorporated in a tip portion of an arm robot for delivering a workpiece to a machine tool or the like.

When a workpiece is processed by a plurality of machine tools, an automatic workpiece transfer machine for transferring the workpiece to each of a plurality of machine tools is used. The automatic workpiece transfer machine includes a traveling device for moving between machine tools, a transfer robot for delivering workpieces to and from the machine tool, and the like. For example, the transfer robot is provided with a robot hand at the tip of the arm robot, and the work gripped by the robot hand is carried to the processing position in the machine tool by the expansion and contraction of the arm robot, where the work is transferred. Done.

The robot hand is constituted by, for example, a chuck device that opens and closes a plurality of chuck claws with a chuck cylinder. In the chuck device, hydraulic oil is supplied to the chuck cylinder, and the workpiece is gripped by the chuck claw in a state where hydraulic pressure is applied. For this reason, in order to keep gripping the workpiece, the state in which the hydraulic pressure is applied to the chuck cylinder must be maintained. Therefore, a check valve is provided in the hydraulic circuit of the chuck device so that the hydraulic pressure of the chuck device does not decrease even when the power is turned off. However, if the hydraulic pump is stopped for a long time, a slight amount of hydraulic oil leaks, and the gripping force of the chuck device decreases. In this regard, Patent Document 1 listed below discloses a spindle chuck for a machine tool that maintains the gripping force.

JP-A-6-226517

The spindle chuck of the above document has a chuck opening / closing mechanism connected to the tip of a piston rod extending from the piston of the chuck cylinder. Since the spindle chuck rotates while gripping the workpiece, it is necessary to maintain the workpiece gripping force without lowering the hydraulic pressure during the work. Accordingly, the piston is provided with eight axial holes parallel to the piston shaft around the piston rod, and pressure holding portions are formed at six of them. However, in such a conventional example, the configuration of the pressure holding portion becomes large, and it is difficult to use the chuck device (robot hand) configured at the tip portion of the arm robot described above. This is because if the robot hand becomes large, it becomes difficult for itself to enter a narrow processing chamber in the machine tool, and the arm robot supporting the heavy robot hand becomes large.

Therefore, an object of the present invention is to provide a chuck device for a robot hand of an arm robot in which the configuration of the pressure holding unit is made compact in order to solve such a problem.

A chuck device for a robot hand of an arm robot according to an aspect of the present invention includes a base member attached to a distal end portion of an arm robot extending from a base portion, and an extension that is assembled to the base member and supplies and discharges hydraulic oil. A cylinder body formed with a side port and a contraction side port, and a rod portion protruding into the cylinder body and inserted into the cylinder body and displaced by a hydraulic pressure in a pair of pressure chambers communicating with the extension side port or the contraction side port A piston with a rod, and the piston with the rod serves as a pressure-holding cylinder body, into which the pressure-holding piston is inserted and communicated with a pressure-holding port formed in the pressure-holding cylinder body. A pressure-holding cylinder in which the pressure-holding piston is displaced toward the tip side of the rod portion, and the pressure-holding pressure Displacement of the rod-attached piston is coupled to a biasing member placed in a space on the tip side in the pressure-holding cylinder body so as to bias the pressure-holding piston to the side, and the rod portion protruding from the cylinder. And a chuck mechanism for opening and closing the plurality of chuck claws.

According to the configuration disclosed above, when the hydraulic oil is supplied to the cylinder body and the piston with the rod is operated, the chuck pawl connected to the rod portion is opened and closed to grip and release the workpiece. When the workpiece is gripped, the hydraulic oil supplied into the cylinder body is further supplied from the pressure holding port to the pressure holding pressure chamber in the pressure holding cylinder, and the pressure holding piston is displaced. At that time, the urging force of the urging member acts on the hydraulic oil in the pressure-holding pressurizing chamber, and furthermore, the hydraulic pressure of the hydraulic oil acting on the piston with the rod in the cylinder body can be maintained. In the robot hand chuck device of the arm robot, a pressure holding unit is compactly formed in a piston with a rod of a cylinder for performing the gripping operation.

It is the perspective view which showed an example of the processing machine line. It is the perspective view which showed a part of internal structure of a processing machine line. It is the side view which showed the operation state of the workpiece conveyance robot with respect to the process module. It is the top view which showed the chuck device for robot hands of a robot hand. It is sectional drawing of the expansion | extension state which showed the chuck | zipper cylinder which comprises a chuck | zipper apparatus. It is sectional drawing of the contracted state which showed the chuck cylinder which comprises a chuck | zipper apparatus.

Next, an embodiment of a chuck device for a robot hand of an arm robot according to the present invention will be described below with reference to the drawings. The arm robot of the present embodiment constitutes an automatic workpiece transfer machine on a processing machine line. The processing machine line refers to a group of processing machines in which a workpiece is transferred to a plurality of processing machines such as machine tools by an automatic workpiece transfer machine, and predetermined processing is performed on the workpiece in each processing machine. FIG. 1 is a perspective view showing an example of a processing machine line.

In the processing machine line 1, a processing machine 5 such as a lathe (hereinafter referred to as “processing module”) 5 is mounted on a base 2 that is a base, and is arranged in the width direction and arranged close to each other. . Each processing module 5 is manufactured with the same width, and is mounted so as to be movable in the front-rear direction via a rail laid on the base 2. In the present embodiment, the machine body width direction in which the processing modules 5 are arranged is referred to as a Y-axis direction, the machine body longitudinal direction movable on the base 2 is referred to as a Z-axis direction, and the vertical direction is referred to as an X-axis direction.

In the processing machine line 1, predetermined processing is performed on the workpiece through the process in each processing module 5. For this reason, the processing machine line 1 is provided with an automatic workpiece transfer machine for transferring workpieces to and from each processing module 5. In the processing module 5, various devices constituting a lathe and the like are covered with an exterior cover 6, and a processing chamber for processing a workpiece is provided therein. A front cover 7 that can be opened and closed is integrated with the exterior cover 6. The front cover 7 is provided for each processing module 5, but the entire processing machine line 1 constitutes one conveyance space. An automatic workpiece transfer machine for transferring a workpiece is provided in the transfer space.

FIG. 2 is a perspective view showing a part of the internal structure of the processing machine line. Specifically, one processing module 5 mounted on the base 2 and an automatic workpiece transfer machine are shown. Two processing modules 5 can be mounted on one base 2, and two sets of rails 11 laid with the same width are provided thereon. On the other hand, the processing module 5 is configured as a movable bed 12 having wheels, and is mounted in a state of being movable on the rail 11. In other words, each of the processing modules 5 shown in FIG. 1 can move in the front-rear direction, and is configured so that maintenance or tool replacement by an operator can be easily performed even in an arrangement close to the machine body width direction.

The machining module 5 is provided with an internal cover 13 that constitutes a machining chamber, in which a spindle chuck for gripping a workpiece, a turret device equipped with a tool, and the like are provided. A transfer port 131 is formed on the front surface of the inner cover 13 as shown in FIG. 3, and a transfer door 14 that opens and closes when the workpiece transfer robot 21 loads and discharges the workpiece is provided. Here, FIG. 3 is a side view showing an operation state of the workpiece transfer robot 21 with respect to the machining module 5. In the processing module 5, the transfer door 14 moves upward as illustrated, and a wide transfer port 131 is opened on the front surface of the inner cover 13. Therefore, the workpiece transfer robot 21 located in the transfer space 70 of the front cover 7 enters the processing chamber in the inner cover 13 and transfers the spindle chuck 16 and the workpiece W.

The workpiece transfer robot 21 is an arm robot having a joint, and a robot hand 22 is provided on the free end side of the arm. As shown in FIG. 2, the workpiece transfer robot 21 is mounted on the traveling platform 23 and is placed in a transfer space 70 constituted by the front cover 7. A support plate 25 is fixed to the front surface of the base 2, and a rail 26 and a rack (not shown) are fixed to the base 2 along the Y-axis direction. On the other hand, a slider that slides with the rail 26 held is fixed to the traveling table 23, and a traveling motor that rotates the pinion meshed with the rack is mounted.

As shown in FIG. 3, the work transfer robot 21 has a pair of first arm members 31 erected with respect to the table 28 of the traveling table 23 fixed at a predetermined interval, and the first arm member 31 has a first joint. A second arm member 32 is connected to the second arm member 32 through the second arm member 32, and a third arm member 33 is connected to the second arm member 32 through the second joint 36. A robot hand 22 is attached to the tip portion of the third arm member 33 in the workpiece transfer robot 21.

The pair of first arm members 31 are plate members each formed of a standing portion 311 extending in the vertical direction and a forward inclined portion 312 bent to the processing module 5 side, and the width of the inner cover 13 of the processing module 5. Are arranged at intervals corresponding to. That is, when the second arm member 32, the third arm member 33, and the robot hand 22 assembled between the pair of first arm members 31 extend as shown by the solid line in FIG. The width is such that it can enter the cover 13. The workpiece transfer robot 21 is configured such that the form of the second arm member 32 and the third arm member 33 changes from the contracted state indicated by the alternate long and short dash line to the extended state indicated by the solid line by driving the first and second joints 35. ing.

At that time, the robot hand 22 moves between a retracted position located between the pair of first arm members 31 and a delivery position for delivering the spindle chuck 16 and the workpiece W. When the workpiece transfer robot 21 contracts, the robot hand 22 can be accommodated between the first arm members 31, and the second arm member 32 and the third arm member 33 can be compacted by the forward inclined portion 312 of the first arm member 31. The workpiece transfer robot 21 is ready to travel in the transfer space 70 in the front cover 7. The forward inclined portion 312 of the first arm member 31 has an effect that the robot hand 22 can reach further through the second arm member 32 and the third arm member 33 when the workpiece transfer robot 21 extends. There is also.

Next, FIG. 4 is a plan view showing the robot hand chuck device of the robot hand 22. As shown in FIG. 3, the robot hand 22 has a base member 38 attached to a third arm member 33, and a robot hand chuck device (hereinafter simply referred to as “chuck device”) 39 is attached to the base member 38. It is assembled. Two chuck devices 39 are mounted on the robot hand 22 in a state where their orientations are changed by 90 degrees. The two chuck devices 39 have the same structure, and are configured to open and close the pair of chuck claws 47 to grip and release the workpiece W.

The chuck device 39 opens and closes the chuck claw 47 by a hydraulic cylinder (chuck cylinder) 40, and the state where the chuck claw 47 grips the workpiece W is maintained in a state where the hydraulic pressure is applied. Therefore, when the work W is gripped, the state where the hydraulic pressure is applied must be maintained even if the power is turned off. Therefore, the chuck device 39 is provided with a pressure holding function for maintaining the gripping state. In particular, since the chuck device 39 constitutes the robot hand 22 attached to the tip portion of the workpiece transfer robot 21, it is required to be small and light. Moreover, the robot hand 22 is equipped with two chuck devices 39. Therefore, the configuration of the pressure holding unit incorporated in the chuck device 39 is required to be compact.

5 and 6 are cross-sectional views showing the chuck cylinder constituting the chuck device 39. FIG. 5 shows an extended state when the workpiece is released, and FIG. 6 shows a contracted state when the workpiece is gripped. This chuck cylinder 40 has a piston 42 with a rod inserted in a cylindrical cylinder body 41. One end of the cylinder body 41 is closed by a lid member 44, and a rod portion 421 of a piston with a rod (hereinafter simply referred to as “piston”) 42 projects from the other end. And between the cylinder main body 41 and the rod part 421, the sealing member 43 is provided double, and the inside of the cylinder main body 41 is kept airtight.

The chuck cylinder 40 is a double-acting cylinder, and the cylinder body 41 is formed with an extension side port 412 communicating with the bottom side extension side pressurizing chamber 411 and contracting with the rod side contraction side pressurizing chamber 413. A side port 414 is formed. A hydraulic circuit including a switching valve, a hydraulic pump, a recovery tank, and the like is connected to the expansion side port 412 and the contraction side port 414 through pipes, respectively, so that hydraulic oil is supplied and discharged. Accordingly, the chuck cylinder 40 extends as shown in FIG. 5 when hydraulic fluid is supplied from the expansion side port 412 and contracts as shown in FIG. 6 when hydraulic fluid is supplied from the contraction side port 414. It comes to work.

As shown in FIG. 4, the chuck device 39 includes a chuck mechanism that opens and closes a pair of chuck claws 47 with the central axis of the piston 42 (rod portion 421) symmetrical. In the chuck mechanism, a pair of crank members 45 are pivotally supported with respect to the base block 37. The crank member 45 is an L-shaped member. A shaft hole is formed at a corner of the crank member 45, and the crank member 45 is supported by a pin 371 to be swingable with respect to the base block 37. A chuck claw 47 is fixed to one end side of the clamp member 45, a long hole 451 is formed on the other end side, and a pin 46 fixed to the rod portion 421 is inserted.

In the chuck device 39, the rod portion 421 of the piston 42 is displaced to a position indicated by a solid line and a one-dot chain line in FIG. At that time, the linear movement of the pin 46 is converted into the swinging motion of the clamp member 45, and the pair of chuck claws 47 is opened and closed. In particular, the chuck claw 47 grips the workpiece W when the chuck cylinder 40 is contracted as shown in FIG. In the present embodiment, a pressure holding portion is formed in the chuck cylinder 40, particularly the piston 42, so that the contracted state, that is, the gripping state of the workpiece can be maintained.

As shown in FIGS. 5 and 6, the piston 42 has a hollow shape, and the opening at the piston side end is closed by the plug block 51. A vent 423 is formed at the tip of the rod portion 421. The piston 42 itself is a pressure-holding cylinder, and a pressure-holding piston 52 is inserted therein. This pressure-holding cylinder is a single-acting cylinder, and a pressure-holding spring 53 is placed in the front end side space 425 of the rod portion 421 inside the piston 42. Accordingly, the pressure retaining piston 52 is always urged toward the stopper block 51 side.

Also, the piston 42 has a pressure-holding port 428 so that hydraulic fluid is supplied to the pressure-holding pressure chamber 426 on the piston portion side. The pressure-holding pressure chamber 426 communicates with the contraction-side pressure chamber 413 of the cylinder body 41 via the pressure-holding port 428. Accordingly, during the contraction shown in FIG. 6, the hydraulic oil is supplied from the contraction side port 414 to the contraction side pressurization chamber 413, but is further supplied to the pressure holding pressure chamber 426 via the pressure retention port 428. It has become so.

The pressure retaining piston 52 is formed in a cylindrical shape and is fitted to the stopper block 51 in a slidable state. The stopper block 51 has a stepped columnar shape, and a guide portion 511 at the tip is inserted into the sliding recess 521 of the pressure retaining piston 52. The guide portion 511 and the sliding recess 521 are in sliding contact with each other, and an O-ring is provided between them to maintain airtightness. The pressure retaining piston 52 is formed with a protruding extension 522 in order to limit the stroke and suppress the amount of hydraulic oil entering and exiting the pressure retaining pressure chamber 426.

Therefore, in the chuck device 39 configured as described above, when the hydraulic oil is supplied to the chuck cylinder 40 from the extension side port 412 to the extension side pressurizing chamber 411, the piston 42 is pressurized and shown in FIG. Such an extended state is obtained. At this time, the hydraulic oil in the contraction side pressurizing chamber 413 is discharged and the pressure is reduced. Then, in the piston 42, the pressure-holding piston 52 is displaced by the urging force of the pressure-holding spring 53, and the hydraulic oil in the pressure-holding pressure chamber 426 that has fallen in pressure is pushed out to the contraction-side pressure chamber 413 side. Will be discharged. Accordingly, the pin 46 is moved by the extension operation of the piston 42, whereby the clamp member 45 is swung, and the chuck device 39 is opened as shown by a one-dot chain line in FIG.

On the other hand, when the hydraulic oil is supplied to the chuck cylinder 40 from the contraction side port 414 to the contraction side pressurizing chamber 413, the piston 42 is pressurized to be in a contracted state as shown in FIG. At this time, the hydraulic oil in the extension side pressurizing chamber 411 is discharged and the pressure is reduced. In the piston 42, the hydraulic oil supplied to the contraction-side pressurizing chamber 413 is also supplied into the pressure-holding pressure chamber 426, and the pressure-holding piston 52 is pressurized. The pressurized pressure retaining piston 52 is displaced while compressing and retaining the pressure retaining spring 53 against the urging force. Therefore, the pin 46 is moved by the contraction operation of the piston 42, whereby the clamp member 45 is swung, and the chuck device 39 is closed as shown by a solid line in FIG.

In the chuck device 39, the workpiece W is gripped by the pair of chuck claws 47 when the chuck cylinder 40 contracts. That is, the workpiece W is gripped by the robot hand 22 of the workpiece transfer robot 21. Therefore, the workpiece transfer robot 21 is moved to the front of the predetermined processing module 5 by the traveling platform 23, and the workpiece W is delivered by driving the workpiece transfer robot 21 as shown in FIG.

In the present embodiment, the chuck device 39 is used even when the power of the processing machine line 1 is turned off or when the work transport robot 21 stops the operation of the processing machine line 1 while holding the workpiece W. The gripping of the workpiece W is maintained. Since the hydraulic pump is normally driven, the pressure in the contraction side pressurizing chamber 413 of the chuck cylinder 40 is maintained. Even if the hydraulic pump stops, the discharge of the hydraulic oil is stopped by the check valve so that the pressure in the contraction side pressurizing chamber 413 is maintained. However, the leakage of hydraulic oil cannot be completely stopped, and if the hydraulic pump stops for a long time, the pressure in the contraction side pressurizing chamber 413 also decreases, so that the gripping force of the workpiece W by the chuck claw 47 is increased. descend. Since the chuck claw 47 holds the workpiece 47 by frictional resistance, the frictional resistance decreases due to a decrease in gripping force, and the workpiece W is displaced or dropped.

In this regard, even if the hydraulic oil in the contraction-side pressurizing chamber 413 decreases due to oil leakage, the chuck device 39 pressurizes the pressure by the amount of hydraulic oil leaked by the pressure-holding spring 53 pushing the pressure-holding piston 52. The volume of the chamber 426 is reduced. For this reason, the pressure at which the hydraulic oil in the contraction-side pressurizing chamber 413 acts on the piston 42 is kept constant, and the gripping force of the pair of chuck claws 47 that grip the workpiece W is always maintained. Therefore, even if hydraulic oil leaks due to the pressure holding portion inside the piston 42, the chuck device 39 generates a force for displacing the piston 42 in the contracting direction, that is, a force for the pair of chuck claws 47 to grip the workpiece W. Can be kept constant.

Further, the chuck cylinder 40 of this embodiment can be reduced in size and weight while having a pressure holding function by incorporating the pressure holding piston 52 inside the piston 42. Therefore, the robot hand 22 including the chuck device 39 can be reduced in size and weight, and can be mounted on the distal end portion of the cantilever-supported workpiece transfer robot 21 extending far. In the processing machine line 1 with a compact design, the work cover robot 21 cannot be made robust and large because the internal cover 13 and the transfer space 70 of the processing module 5 are narrow. In order to meet such a demand, the chuck device 39 can reduce the size of the work transfer robot 21, and the robot hand 22 can be equipped with two chuck devices 39.

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, the chuck device 39 of the above-described embodiment grips the workpiece W when the chuck cylinder 40 is contracted. However, if the chuck mechanism is configured to grip the workpiece W when the chuck cylinder 40 operates to expand, The pressurizing chamber 411 may communicate with the pressurizing chamber 426.

DESCRIPTION OF SYMBOLS 21 ... Work conveyance robot 22 ... Robot hand 39 ... Robot hand chuck device 40 ... Chuck cylinder 41 ... Cylinder body 42 ... Piston with rod 52 ... Piston for pressure retention 53 ... Spring for pressure retention

Claims

A base member attached to the distal end portion of the arm robot extending from the base portion;
A cylinder body which is assembled to the base member and has an extension side port and a contraction side port for supplying and discharging hydraulic oil;
A piston with a rod that is inserted into the cylinder body in a state in which the rod portion protrudes and is displaced by a hydraulic pressure in a pair of pressurizing chambers that communicate with the extension side port or the contraction side port;
The piston with the rod serves as a pressure-holding cylinder body, and the pressure-holding piston is inserted into the main body. A pressure-holding cylinder that is displaced toward the tip of the rod part;
An urging member placed in a front end side space in the pressure-holding cylinder main body so as to urge the pressure-holding piston toward the pressure-holding pressure chamber;
A chuck device for a robot hand of an arm robot, the chuck device being connected to the rod portion protruding from the cylinder and having a chuck mechanism for opening and closing a plurality of chuck claws by displacement of the piston with the rod.
The piston with rod includes a piston portion that slides within the cylinder body, the rod portion in which the pressure-holding port is formed in a cylindrical side surface portion, and a vent hole is formed in a tip surface portion protruding from the cylinder; The chuck device for a robot hand of an arm robot according to claim 1, comprising:
The piston with a rod is formed by forming the pressure-holding cylinder in an airtight state in which an opening formed on the side opposite to the rod portion is closed by a lid member,
3. The chuck device for a robot hand of an arm robot according to claim 2, wherein the lid member is formed with a piston guide part formed with a convex part that fits into a concave part of the pressure-holding piston.