JP7367338B2 - Workpiece gripping device - Google Patents

Description

The present invention relates to a workpiece gripping device for gripping a workpiece.

Conventionally, in a processing line for processing workpieces, various processing devices have been arranged along the conveyance direction of the workpiece. When a workpiece is carried into a processing device, it is processed by the processing device, carried out, and carried into the next processing device. A robot is used to carry the workpiece into and out of the processing device, and the robot has gripping claws that can grip the workpiece and release the gripped workpiece. A workpiece gripping device is provided with a so-called chuck.

For example, in Patent Document 1, one electrode is provided on the base that supports the gripping claws, the other electrode is provided on the gripping claws, and when the workpiece is gripped by the gripping claws using the electrodes, the workpiece is A chuck device with a measurement function that can measure the outer diameter is described. The chuck device (workpiece gripping device) described in Patent Document 1 has three gripping claws (movable chuck claws) arranged along a virtual circle along the outer periphery of a workpiece. The gripping claws are moved radially inward of the virtual circle to grip the workpiece, and the gripping claws are moved radially outward of the virtual circle to release the gripped workpiece.

Japanese Patent Application Publication No. 2010-240833

For example, in a conventional processing line, if a processing device is installed to cut the outer periphery of a workpiece, the outer circumference of the workpiece when it is brought into the processing device is a truncated cone, and the workpiece is not processed by the processing device. The outer periphery of the workpiece may be cylindrical when it is unloaded. In this case, the outer periphery of the truncated conical workpiece must be gripped by gripping claws when being carried in, and the outer periphery of the cylindrical workpiece must be gripped by gripping claws when being carried out.

In the above case, if the gripping surface of the gripping claw is adjusted so that it makes surface contact with the outer peripheral surface of the truncated conical workpiece, the gripping surface and the workpiece will come into point contact (or (line contact), and stable gripping may not be possible. In addition, if the gripping surface of the gripping claw is adjusted so that it makes surface contact with the outer peripheral surface of a cylindrical workpiece, the gripping surface and the workpiece will come into point contact (or line contact) in the case of a truncated cone-shaped workpiece. Stable grip may not be possible. Therefore, at the location of such processing equipment, a workpiece gripping device equipped with a gripping claw for gripping a truncated conical workpiece and a workpiece gripping device equipped with a gripping claw for gripping a cylindrical workpiece are used. Both are installed at the tip of the robot, or two robots are arranged, one for gripping a truncated cone-shaped workpiece and the other for gripping a cylindrical workpiece.

In the chuck device (workpiece gripping device) described in Patent Document 1, the gripping claws only move radially inward or radially outward of a virtual circle. Therefore, in order to load and unload a truncated conical workpiece into a processing device that processes a cylindrical workpiece, a chuck device equipped with gripping claws for gripping the truncated conical workpiece and a cylindrical A chuck device equipped with a gripping claw that grips a workpiece, and a robot that grips a truncated cone-shaped workpiece and a robot that grips a cylindrical workpiece. It is necessary to place the machine robot. In this case, the structure of the robot becomes complicated, the robot size is increased by one size, or a large space for arranging two robots is required, which is not preferable in terms of cost and layout dimensions.

The present invention was devised in view of these points, and it is possible to maintain the outer peripheral surface and the surface of the workpiece regardless of whether the workpiece has a truncated conical outer shape or a cylindrical outer shape. It is an object of the present invention to provide a workpiece gripping device having gripping claws that can contact and appropriately grip the workpiece.

In order to solve the above problems, a first aspect of the present invention provides a plurality of claw units arranged along the circumferential direction of a virtual circle along the outer periphery of a workpiece to be gripped, and a driving device that simultaneously moves the gripping claws radially outward or radially inwardly of a virtual circle, and having a gripping claw rotation axis that is substantially parallel to the tangential direction of the virtual circle with respect to the claw unit, around the gripping claw rotation axis; and a gripping pawl that is supported by the pawl unit so as to be rotatable, and that grips the workpiece with a gripping surface provided on the inner diameter side of the virtual circle.

Next, a second invention of the present invention is the workpiece gripping device according to the first invention, wherein the claw unit is provided with a gripping claw attitude maintaining mechanism, and the grasping claw attitude maintaining mechanism is provided with a gripping claw attitude maintaining mechanism. has an elastic member that can be deformed and restored, and when the gripping claw does not grip the workpiece, the restored elastic member allows the gripping claw to pivot around the gripping claw rotation axis. When the position is returned to a predetermined rotation position and the gripping claw is gripping the workpiece, the elastic member is deformed and the gripping surface of the gripping claw is in contact with the surface of the workpiece. The workpiece gripping device allows the gripping claws to rotate around the gripping claw rotation axis along the surface of the workpiece to be gripped.

Next, a third invention of the present invention is the workpiece gripping device according to the first invention or the second invention, wherein the claw unit is provided with a workpiece pushing mechanism, and the workpiece The object pushing mechanism is configured such that, before the workpiece is gripped by the gripping claws, when the claw unit is pressed against the workpiece along a direction of an imaginary axis perpendicular to the plane of the virtual circle, the workpiece is A workpiece gripping device that pushes the workpiece in a direction opposite to the pushed direction when the workpiece is pushed in the opposite direction to be pushed and the workpiece gripped by the gripping claw is released. be.

Next, a fourth invention of the present invention is the workpiece gripping device according to any one of the first to third inventions, wherein each of the claw units is driven by the drive device to a movable part that moves radially outward or radially inward of a circle; an adapter disposed to be sandwiched between the movable part and the fixed part; and a fixed part that fixes the adapter to the movable part. , and the adapter is provided with the gripping claws.

Next, a fifth invention of the present invention is the workpiece gripping device according to the fourth invention, wherein the adapter is provided with an adapter-side reference surface and a positioning recess, and the movable The portion is provided with a movable portion side reference surface that faces and contacts the adapter side reference surface, and a ball plunger that fits into the positioning recess, and the fixed portion is provided with a movable portion side reference surface that faces and contacts the adapter side reference surface. The workpiece gripping device is provided with an adapter pressing mechanism that presses and fixes the adapter.

Next, a sixth invention of the present invention is the workpiece gripping device according to the fifth invention, wherein the adapter pressing mechanism has an eccentric cam.

According to the first invention, the gripping claws are rotatable with respect to the claw unit around the rotation axis parallel to the tangential direction of the imaginary circle, so that the gripping claws can rotate between the workpieces having a truncated conical outer shape and the workpiece having a cylindrical outer shape. It is possible to realize a gripping claw that can appropriately grip any workpiece by making surface contact with the outer peripheral surface of the workpiece.

According to the second aspect of the invention, the direction of the gripping claws, which can be rotated around the rotation axis immediately before gripping the workpiece, reaches the rotation limit position due to gravity or the like and is not facing the appropriate direction; It is possible to avoid a situation where each of the plurality of gripping claws turns in a different direction, and to maintain the direction of the gripping claw just before gripping in a stable direction (in the direction of a predetermined turning position). Further, the direction of the gripping claws, which are deformed and rotated while gripping a workpiece, can be automatically returned to an appropriate direction by the elastic members after the workpiece is released. By using an elastic member that can be deformed and restored, the gripping claw posture maintaining mechanism can be realized with a very simple structure.

According to the third invention, the workpiece extrusion mechanism stores force for pushing out the workpiece when gripping the workpiece, and uses the stored force when releasing the gripped workpiece. Push out the workpiece. Thereby, when releasing the gripped workpiece, the workpiece can be pressed against the processing device and brought into close contact.

The movement distance for simultaneously moving each claw unit radially outward or radially inward of the virtual circle is determined by the drive device, and is not a very large distance. Therefore, when machining workpieces of various diameters on a machining line, it may be necessary to replace the gripping claws with gripping claws that correspond to the diameters of the workpieces to be gripped. According to the fourth invention, it is easy to attach and detach the gripping claws (adapter having gripping claws) to the movable part, so the work time for replacing the gripping claws according to the diameter of the workpiece to be gripped can be further shortened. can do.

According to the fifth invention, the positioning mechanism for positioning the adapter with respect to the movable part can be realized with a simple structure using the adapter side reference surface, the movable part side reference surface, the positioning recess and the ball plunger. can.

According to the sixth invention, the adapter pressing mechanism for fixing the adapter positioned with respect to the movable part can be realized with a simple structure using an eccentric cam.

FIG. 2 is a perspective view illustrating an example of a processing line in which a plurality of processing devices and robots are arranged along the workpiece transport direction. FIG. 2 is a diagram illustrating an example of the appearance of a robot. FIG. 3 is a front view of a workpiece gripping device provided at the tip of the robot, as seen from direction III in FIG. 2; 4 is a side view of the workpiece gripping device, as seen from the IV direction in FIG. 3. FIG. FIG. 3 is a side view illustrating an example of the appearance of a movable part, a fixed part, an adapter, and a gripping claw in the claw unit. It is a perspective view explaining an example of the appearance of a movable part, a fixed part, and an adapter in a claw unit. 6 is a view seen from the VII direction in FIG. 5. FIG. FIG. 3 is a diagram illustrating a gripping claw that pivots around a pivot axis, a predetermined pivoting position of the grasping claw, and an elastic member that deforms and restores its original state. 9 is a sectional view taken along line IX-IX in FIG. 8. FIG. FIG. 3 is a diagram illustrating the order in which the workpiece is gripped by the workpiece gripping device, and is a diagram illustrating a state before the workpiece is gripped and before the workpiece gripping device comes into contact with the workpiece. 11 is a diagram illustrating a state in which the workpiece gripping device is pressed against the workpiece from the state shown in FIG. 10. FIG. 12 is a diagram illustrating a state in which the workpiece gripping device grips the workpiece from the state shown in FIG. 11. FIG. 13 is a diagram illustrating a state in which the workpiece gripping device releases the workpiece from the state shown in FIG. 12. FIG. FIG. 3 is a diagram illustrating an example of a state in which a workpiece having a truncated conical outer shape is gripped. FIG. 3 is a diagram illustrating an example of a state in which a workpiece having a cylindrical outer shape is gripped.

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. In addition, when the X-axis, Y-axis, and Z-axis are shown in the figure, each axis is orthogonal to each other, the Z-axis direction indicates the vertically upward direction, and the X-axis direction and the Y-axis direction indicate the horizontal direction. It shows the direction.

●[Example of processing line (Figure 1)]
FIG. 1 shows an example of a processing line 1 for processing workpieces. The processing line 1 includes transport devices C1 and C2, processing devices S1 and S2, a self-propelled robot R, and the like. The processing devices S1 and S2 include a column 90 that moves in the front-rear direction, a spindle head 91 that moves in the vertical direction with respect to the column 90, and a workpiece to which a workpiece is attached and rotates around a vertical axis and moves in the left-right direction. A material table 92 is provided. The workpiece table 92 is equipped with an unillustrated chuck device that grips the workpiece on the inner diameter or the outer diameter.

The workpiece transported to the workpiece position W1 by the transport device C1 is gripped by the robot R, and internally gripped by the chuck device of the workpiece table 92 of the processing device S1 at the workpiece position W2. For example, the workpieces at workpiece positions W1 and W2 are cast metals, have a draft angle, and have a truncated conical outer shape.

When the workpiece is internally gripped at the workpiece position W2, the workpiece table 92 of the processing device S1 rotates 180 degrees around the vertical axis, the workpiece is placed on the column 90 side, and the column 90 is moved forward. The spindle head 91 moves vertically and the workpiece table 92 moves horizontally, thereby cutting the outer periphery of the workpiece. When the cutting of the workpiece is completed, the column 90 moves backward, the workpiece table 92 rotates 180 degrees around the vertical axis, and the workpiece becomes closer to the robot R.

For example, the processing device S1 is a processing device that cuts the outer periphery of a workpiece, and cuts the outer periphery of a truncated conical workpiece into a cylindrical shape. In this case, when the robot R grips and transports the workpiece from the workpiece position W1 to the workpiece position W2, the robot R grips the workpiece having a truncated conical external shape and transfers the workpiece from the workpiece position W2 to the workpiece position W3. In the case of gripping and conveying a workpiece, the workpiece has a cylindrical outer shape.

The workpiece having a cylindrical outer shape placed at the workpiece position W2 is gripped by the robot R and transported to the workpiece position W3 of the processing device S2. The workpiece transported to the workpiece position W3 of the processing device S2 is gripped by the chuck device on the workpiece table 92 of the processing device S2. When the workpiece is gripped at the outer diameter at the workpiece position W3, the workpiece table 92 of the processing device S2 is rotated 180° around the vertical axis so that the workpiece is on the column 90 side, and the column 90 is moved forward. The spindle head 91 moves vertically, and the workpiece table 92 moves horizontally, thereby cutting the inner periphery of the workpiece. When the cutting of the workpiece is completed, the column 90 moves backward, the workpiece table 92 rotates 180 degrees around the vertical axis, and the workpiece becomes closer to the robot R. The processed workpiece is placed at a workpiece position W3 of the processing device S2. The workpiece processed by the processing device S2 and placed at the workpiece position W3 is gripped by the robot R and placed at the workpiece position W4 of the transport device C2.

For example, the processing device S2 is a processing device that processes the inner wall surface of a cylindrical workpiece. In this case, when the robot R grips and transports the workpiece from the workpiece position W2 to the workpiece position W3, the robot R grips the workpiece with a cylindrical outer shape and transfers the workpiece from the workpiece position W3 to the workpiece position W4. When conveying a workpiece while gripping it, the workpiece has a cylindrical outer shape.

The workpiece gripping device 70 described in this embodiment is attached to the tip of the robot R in the above example, and is capable of handling either a workpiece having a truncated cone shape or a workpiece having a cylindrical shape. Even if it is a workpiece, it has gripping claws that can appropriately grip the workpiece by making surface contact with the outer peripheral surface of the workpiece.

● [Exterior of Robot R (Figure 2)]
Next, the appearance etc. of the robot R will be explained using FIG. 2. The robot R is a six-axis robot that moves by itself in the left-right direction. The robot R includes a guide part T1 (see FIG. 1), a support part 10, a base part 11, a first arm part 21, a second arm part 22, a third arm part 23, a first wrist part 24, and a second wrist part 25. , a workpiece gripping device 70, etc.

The guide portion T1 (see FIG. 1) is erected so as to extend in the left-right direction on the floor surface in front of the processing apparatuses S1 and S2 (see FIG. 1). The support part 10 is guided and supported by the guide part T1 (see FIG. 1) so as to be movable in the left-right direction, and has a pinion that meshes with an unillustrated rack of the guide part T1 and a servo motor that rotationally drives the pinion.

The base portion 11 is configured to rotate around a robot rotation axis J1 that is perpendicular to the support portion 10. One end of the first arm part 21 is connected to the tip of the base part 11 so as to be able to rotate about the robot rotation axis J2 which is parallel to the direction perpendicular to the robot rotation axis J1 with respect to the base part 11. ing. One end of a second arm section 22 is connected to the other end of the first arm section 21 so as to be able to rotate around a robot rotation axis J3 parallel to the robot rotation axis J2 with respect to the first arm section 21. ing.

One end of the third arm part 23 is attached to the other end of the second arm part 22 so as to be rotatable about the robot rotation axis J4 which is parallel to the direction orthogonal to the robot rotation axis J3 with respect to the second arm part 22. is connected. The other end of the third arm part 23 is attached to one side of the first wrist part 24 so as to be rotatable about the robot rotation axis J5 which is parallel to the direction orthogonal to the robot rotation axis J4 with respect to the third arm part 23. The ends are connected.

One end of a second wrist portion 25 is connected to the other end of the first wrist portion 24 so as to be rotatable about the gripping device rotation axis J6 that is perpendicular to the robot rotation axis J5 with respect to the first wrist portion 24. ing. A workpiece gripping device 70 is provided on the other end side of the second wrist portion 25. Note that, in FIG. 2, illustrations of a rotation motor and the like that rotate each arm part and the like around the respective robot rotation axes and around the gripping device rotation axis are omitted.

The workpiece gripping device 70 includes a plurality of claw units 72, a drive device 71, and gripping claws 73 provided in each claw unit 72 to grip the workpiece.

●[Appearance of workpiece gripping device 70 (Fig. 3, Fig. 4)]
Next, the appearance etc. of the workpiece gripping device 70 will be explained using FIGS. 3 and 4. As shown in FIG. 3, the claw units 72 are provided on the outer peripheral surface of the second wrist portion 25, and are arranged at equal intervals along the circumferential direction of the virtual circle V1 along the outer periphery of the workpiece to be gripped. ing. In the description of this embodiment, a workpiece gripping device 70 having three claw units 72 will be described.

The drive device 71 is attached to one end of the second wrist portion 25 and includes a cylinder 71A driven by compressed air or the like, and three sliders 71B that slide the three claw units 72. The movement of the piston of the cylinder 71A is configured to be transmitted to the three sliders 71B by a cam mechanism. The respective claw units 72 are attached to the three sliders 71B, and the drive device 71 simultaneously moves the respective claw units 72 radially outward or radially inward of the virtual circle V1.

Each gripping claw 73 has gripping claw rotation axes JU1 to JU3 that are substantially parallel to the tangential direction of the virtual circle V1 with respect to each claw unit 72, and is able to rotate around the gripping claw rotation axes JU1 to JU3. It is supported by each claw unit 72 as shown in FIG. Each of the gripping claws 73 can grip the workpiece W with a gripping surface 73M provided on the inner diameter side of the virtual circle V1 (see FIG. 4).

Each claw unit 72 has a movable part 74, an adapter 75, and a fixed part 76, as shown in FIGS. 3 and 4. Hereinafter, the details of the claw unit 72 having the gripping claw rotation axis JU1 will be explained in FIG. 3, and the claw units having the gripping claw rotation axes JU2 and JU3 are the same, so the explanation will be omitted.

● [Structures of the movable part 74, adapter 75, and fixed part 76 (Figs. 4 to 9)]
As shown in FIG. 5, the movable part 74 is moved radially outward (F3 direction in FIG. 5) or radially inward (F2 direction in FIG. 5) of the virtual circle V1 (see FIG. 3) by the drive device 71. Move to. Furthermore, the movable part 74 is provided with a fixed part 76, as shown in FIGS. 5 and 6.

As shown in FIGS. 5 and 6, the movable portion 74 is formed with an insertion space 74S through which the adapter arm portion 75F of the adapter 75 is inserted. Further, as shown in FIGS. 4 to 6, when the adapter arm portion 75F is inserted into the insertion space 74S, the movable portion A side reference surface 74M is formed. Further, as shown in FIGS. 4 to 6, when the adapter arm part 75F is inserted into the insertion space 74S, the insertion space 74S is located in the movable part 74 at a position facing the positioning recess 75P formed in the adapter arm part 75F. A ball plunger 74P is provided that protrudes inward and is biased toward the adapter arm portion 75F. The movable part side reference surface 74M and the adapter side reference surface 75M constitute a positioning mechanism M3 that positions the adapter 75 with respect to the movable part 74, and a positioning recess 75P and a ball plunger 74P that fits into the positioning recess 75P. A positioning mechanism M4 for positioning the adapter 75 with respect to the movable portion 74 is configured.

Further, as shown in FIG. 6, the adapter arm part 75F inserted into the insertion space 74S is exposed on the side of the fixed part 76 on the side of the adapter arm part 75F with respect to the position of the fixed part 76 provided on the movable part 74. A pressing opening 74K is opened. A camshaft hole 74H is formed near the pressing opening 74K, into which the camshaft of the eccentric cam 76A is inserted. The fixed part 76 has an eccentric cam 76A and a pressing member 76B, as shown in FIG. is inserted into the camshaft hole 74H of the movable part 74 and fixed with a nut 76C, and the fixed part 76 is arranged as shown in FIG. When the fixing portion 76 (the eccentric cam 76A and the pressing member 76B) is placed in the cam shaft hole 74H, the pressing member 76B is placed in the pressing opening 74K shown in FIG.

When the adapter arm portion 75F of the adapter 75 is inserted into the insertion space 74S shown in FIGS. 5 and 6, it is sandwiched between the fixed portion 76 and the movable portion 74, as shown in FIG. As described above, the adapter arm portion 75F is positioned relative to the movable portion 74 by the adapter side reference surface 75M, the movable portion side reference surface 74M, the positioning recess 75P, and the ball plunger 74P shown in FIGS. 5 and 6. (See Figure 4). Since the eccentric cam 76A is eccentric, when the eccentric cam 76A is rotated clockwise from the state shown in FIG. 4, the eccentric cam 76A presses the pressing member 76B against the adapter arm portion 75F , and 75F is firmly fixed to the movable part 74. In this way, the camshaft 76A attached to the camshaft hole 74H and the pressing member 76B constitute an adapter pressing mechanism M5.

Further, as shown in FIGS. 4 and 5, the adapter arm portion 75F is provided with a workpiece extrusion mechanism M2 having an extrusion urging member 75A, an extrusion support member 75B, and an extrusion member 75C. The extrusion member 75C is supported by the extrusion support member 75B so as to be able to reciprocate in the direction along the gripping device rotation axis J6 (corresponding to the imaginary axis perpendicular to the plane of the imaginary circle V1 as shown in FIG. 3). ). Further, the pushing member 75C is urged in a direction toward the gripping claw 73 along the gripping device rotation axis J6 by the pushing urging member 75A, which is urged by an elastic member or the like. Due to this bias, when a workpiece is not gripped, a gap ΔH is formed between the push-out member 75C and the adapter arm portion 75F, as shown in FIG.

FIG. 7 is a view of the periphery of the gripping claw 73 in FIG. 5 viewed from the VII direction. 8 is an enlarged view of the vicinity of the gripping claw 73 in FIG. 5, and FIG. 9 is a sectional view taken along line IX-IX in FIG. As shown in FIGS. 5 and 7 to 9, a gripping claw support part 75E is fixed to the adapter arm part 75F, and the gripping claw 73 rotates around the gripping claw rotation axis JU1 with respect to the gripping claw support part 75E. It is supported so that it can rotate. The gripping claw 73 has a gripping surface 73M that makes surface contact with the outer peripheral surface of the workpiece on the side facing the workpiece to be gripped. As shown in FIG. 3, the gripping surface 73M has an arc shape corresponding to the diameter of the virtual circle V1. Furthermore, a supported recess 73A having a concave shape is formed on the opposite side of the gripping claw 73 from the gripping surface 73M. As shown in FIGS. 5 and 7 to 9, an elastic member 75D is inserted into the supported recess 73A. As shown in FIGS. 7 and 9, the elastic member 75D is supported such that its posture is variable with respect to the gripping claw support portion 75E. As shown in FIG. 9, the elastic member 75D is prevented from coming off by the collar 75DA.

The elastic member 75D is made of an elastic body that can be deformed and restored, and as shown in FIG. 7, its posture is also variable. For this reason, the elastic member 75D maintains the position and shape shown in FIGS. 5, 7, and 9, for example, when no external force is applied (when no workpiece is gripped), and the gripping claw rotation axis The gripping claw 73, which is supported so as to be pivotable around the JU1, is maintained at a predetermined pivoting position shown in FIG. Further, the gripping claw 73 shown by a solid line in FIG. 8 is at a predetermined turning position, and the predetermined turning position is set such that the gripping surface 73M is in surface contact with a workpiece having a cylindrical outer shape, for example. That is, the predetermined turning position is set such that the gripping surface 73M is parallel to the gripping device turning axis J6 (the virtual axis perpendicular to the plane of the virtual circle V1 shown in FIG. 3). As shown by the two-dot chain line in FIG. 8, the gripping claw 73 can rotate clockwise and counterclockwise at a rotation angle θ about the gripping claw rotation axis JU1 from a predetermined rotation position shown by the solid line. It is. This rotation of the gripping claws 73 allows the gripping claws 73 to rotate along the outer shape of the workpiece, regardless of whether the outer shape of the workpiece is a truncated cone or a cylinder. can be brought into surface contact with the outer peripheral surface of the workpiece.

●[Workpiece gripping device 70 grips a workpiece with a truncated cone shape and releases the gripped workpiece (Figures 10 to 13)]
How a workpiece having a truncated conical outer shape is gripped and how the workpiece is released using the workpiece gripping device 70 having the structure described above will be described with reference to FIGS. 10 to 13.

10 to 13 show a workpiece W having a truncated conical outer shape placed at workpiece position W1 in FIG. The situation is shown when the workpiece W is transported and released at the workpiece position W2.

FIG. 10 shows a state in which the workpiece gripping device 70 approaches the workpiece W placed at the workpiece position W1, and a state before the workpiece gripping device 70 contacts the workpiece W. It shows. In this state, the movable portion 74 is moved radially outward (in the direction F3 shown in FIG. 13). Further, since the workpiece gripping device 70 is not in contact with the workpiece W, the extrusion member 75C is urged in the direction of the workpiece W by the extrusion urging member 75A, and the extrusion member 75C and the adapter arm portion 75F are A gap ΔH is formed between them. Furthermore, since the gripping claws 73 are not in contact with the workpiece W, they are held at a predetermined rotational position. Note that the predetermined rotation position in this case is a rotation position where the gripping surface 73M of the gripping claw 73 is parallel to the outer peripheral surface of the workpiece having a cylindrical outer shape, and the gripping surface 73M is parallel to the gripping device rotation axis J6 ( The turning position is set to be parallel to the virtual axis (corresponding to the virtual axis perpendicular to the plane of the virtual circle V1 shown in FIG. 3). Note that the state in FIG. 10 shows an example in which a gap ΔR is formed between the outer peripheral surface of the workpiece W and the gripping surface 73M.

11 shows that the workpiece gripping device 70 is moved in the direction of the workpiece W (direction F1 in FIG. 11) from the state shown in FIG. 10 along the gripping device rotation axis J6, and the workpiece gripping device 70 is The state in which it is pressed against the workpiece W is shown. In this state, the extrusion member 75C (and the extrusion biasing member 75A and extrusion support member 75B) is pushed by the workpiece W to the side opposite to the workpiece W (the side opposite to the direction of F1), and as shown in FIG. The gap ΔH shown disappears. In this case, the force that pushed the extrusion member 75C (and the extrusion biasing member 75A and the extrusion support member 75B) to the opposite side of the workpiece W is stored in the extrusion biasing member 75A. As shown in FIG. 11, before gripping the workpiece W with the gripping claws 73, the jaw unit 72 against the workpiece W, the extrusion biasing member 75A, extrusion support member 75B, extrusion Member 75C (ie, the workpiece extrusion mechanism) is pushed in.

FIG. 12 shows a state in which the movable part 74 is moved radially inward (direction F2 in FIG. 12) by the drive device 71 from the state shown in FIG. 11, and the workpiece W is gripped by the gripping claws 73. It shows. In this state, the extrusion biasing member 75A, the extrusion support member 75B, and the extrusion member 75C are maintained in the pushed state, and the gripping surface 73M of the gripping claw 73 is in surface contact with the outer peripheral surface of the workpiece W. Further, since the outer shape of the workpiece W is a truncated cone, the gripping claw 73 automatically rotates around the gripping claw rotation axis JU1 so that the outer peripheral surface of the workpiece W inclined at an angle θ1 and the gripping surface 73M come into surface contact. Turn around. When the gripping claw 73 rotates, the elastic member 75D is deformed by the supported recess 73A, and its posture also changes. In the gripping state shown in FIG. 12, the workpiece W is transported from the workpiece position W1 shown in FIG. 1 to the workpiece position W2.

FIG. 13 shows that the movable part 74 is moved radially outward (direction F3 shown in FIG. 13) by the drive device 71 from the state shown in FIG. 12 to separate the gripping claws 73 from the workpiece W. A state in which the workpiece W is released is shown. In this state, a gap ΔR similar to that shown in FIG. 11 is formed between the gripping claws 73 and the workpiece W. When the workpiece W is released, the force stored in the extrusion biasing member 75A is released, and the extrusion member 75C pushes the workpiece W away from the claw unit 72 (in the opposite direction to the pushed direction). . Further, the elastic member 75D, which has been deformed and its posture changed, recovers from its deformation and returns to its posture, thereby automatically pivoting the gripping claws 73 to a predetermined pivoting position.

●[A state in which a workpiece with a truncated conical external shape is gripped (Fig. 14) and a state in which a workpiece with a cylindrical external shape is gripped (Fig. 15)]
FIG. 15 shows an example of a state in which a workpiece W having a cylindrical outer shape is being gripped. For example, FIG. 1 shows the state in which the robot R grips the workpiece when it transports the workpiece at the workpiece position W3 to the workpiece position W4. When gripping a workpiece W having a cylindrical outer shape, the rotation angle θ2 of the gripping claws 73 from a predetermined rotation position (the rotation position where the gripping device rotation axis J6 and the gripping surface 73M are parallel) is almost zero. Therefore, the elastic member 75D does not deform or change its posture. In other words, the rotation position of the gripping claws 73 is maintained at a predetermined rotation position both when the workpiece W is gripped and when the workpiece W is released.

FIG. 14 is an enlarged view of the surroundings of the gripping claws 73 in FIG. 12, and shows an example of a state in which the gripping claws 73 are gripping a workpiece W having a truncated conical outer shape. When gripping a workpiece W having a truncated conical outer shape, the gripping claws 73 move to a predetermined rotational position (where the gripping device rotation axis J6 and the gripping surface 73M are parallel) along the angle θ1 of the inclination of the outer circumferential surface of the workpiece W. The gripping surface 73M automatically rotates at an angle θ1 from the rotation position (rotation position), and the gripping surface 73M comes into surface contact with the outer circumferential surface of the workpiece W. At this time, the elastic member 75D is deformed by the supported recess 73A, and its posture also changes.

That is, when gripping a workpiece W having a truncated conical outer shape, the elastic member 75D (grasping claw posture maintenance mechanism) is deformed (or its posture is changed) by the supported recess 73A, and the gripping surface of the gripping claw 73 is The gripping claws 73 are allowed to rotate around the gripping claw rotation axis JU1 along the workpiece gripped surface (outer peripheral surface) which is the surface of the workpiece with which the gripping claws 73M are in contact.

When the workpiece W is released and the gripping claws 73 are not gripping the workpiece W, the elastic member 75D, which has been restored from the deformation (its posture has also been restored), rotates around the gripping claw rotation axis JU1 of the gripping claws 73. The position is automatically returned to a predetermined rotation position (a rotation position where the gripping device rotation axis J6 and the gripping surface 73M are parallel).

● [Effect of the present application]
As explained above, in the workpiece gripping device 70 described in this embodiment, since the gripping claws 73 can be rotated around the gripping claw rotation axis JU1, Regardless of whether the workpiece is in the shape of a truncated cone, the workpiece can be appropriately gripped by bringing the gripping surface 73M into surface contact with the outer peripheral surface of the workpiece.

Furthermore, by having the gripping claw posture maintaining mechanism M1 composed of the elastic member 75D and the supported recess 73A, the rotation position of the gripping claws 73 is stably maintained at a predetermined rotation position when the workpiece is not gripped. When the workpiece is maintained or restored and the workpiece is gripped, the gripping claws 73 can be appropriately allowed to rotate around the gripping claw rotation axis JU1 (JU2, JU3).

Furthermore, by having the workpiece extrusion mechanism M2 composed of the extrusion urging member 75A, the extrusion support member 75B, and the extrusion member 75C, when releasing the gripped workpiece, the workpiece is pressed against the processing device. Can be placed in close contact.

Furthermore, it has positioning mechanisms M3 and M4 that are configured by an adapter-side reference surface 75M and a positioning recess 75P of the adapter arm portion 75F of the adapter 75, a movable-portion-side reference surface 74M of the movable portion 74, and a ball plunger 74P. Therefore, positioning when the adapter 75 is attached to the movable part 74 (or when it is replaced) can be performed easily and in a short time. Furthermore, in order to firmly fix the positioned adapter 75 to the movable part 74, by having an adapter pressing mechanism M5 composed of an eccentric cam 76A and a pressing member 76B, fixing and releasing can be performed simply by rotating the eccentric cam 76A. Since this is easy, the adapter 75 can be installed or replaced very easily and in a short time.

The workpiece gripping device 70 of the present invention is not limited to the configuration, structure, shape, appearance, etc. described in this embodiment, and various changes, additions, and deletions can be made without changing the gist of the present invention. be. For example, the gripping claw posture maintaining mechanism M1 (elastic member 75D and the supported recess 73A), the workpiece extrusion mechanism M2 (the extrusion biasing member 75A, the extrusion support member 75B, and the extrusion member 75C), the positioning mechanism M3 (the movable part side reference surface 74M and adapter side reference surface 75M), positioning mechanism M4 (ball plunger 74P and positioning recess 75P), adapter pressing mechanism M5 (eccentric cam 76A and pressing member 76B), etc. may be omitted.

In addition, the gripping claw posture maintaining mechanism M1 (elastic member 75D and supported recess 73A), workpiece extrusion mechanism M2 (extrusion urging member 75A, extrusion support member 75B and extrusion member 75C), positioning mechanism M3 (movable part side reference surface 74M and adapter side reference surface 75M), positioning mechanism M4 (ball plunger 74P and positioning recess 75P), and adapter pressing mechanism M5 (eccentric cam 76A and pressing member 76B), the shapes, structures, configurations, etc. of this embodiment are the same. It is not limited to the described shape, structure, configuration, etc., and various structures, configurations, etc. can be used.

In the description of this embodiment, an example has been described in which the predetermined rotation position of the gripping claw 73 is a position where the gripping surface 73M is parallel to the gripping device rotation axis J6, but the gripping surface 73M is parallel to the gripping device rotation axis J6. A position tilted at a predetermined angle of inclination may be set as a predetermined turning position.

1 Processing line 10 Support part 11 Base part 21 First arm part 22 Second arm part 23 Third arm part 24 First wrist part 25 Second wrist part 70 Workpiece gripping device 71 Drive device 71A Cylinder 71B Slider 72 Claw unit 73 Gripping claw 73A Supported recess (gripping claw posture maintenance mechanism)
73M Gripping surface 74 Movable part 74H Cam shaft hole 74K Pressing opening 74M Movable part side reference surface (positioning mechanism)
74P ball plunger (positioning mechanism)
74S Insertion space 75 Adapter 75A Extrusion biasing member (workpiece extrusion mechanism)
75B Extrusion support member (workpiece extrusion mechanism)
75C Extrusion member (workpiece extrusion mechanism)
75D Elastic member (gripping claw posture maintenance mechanism)
75E Gripping claw support part 75F Adapter arm part 75M Adapter side reference surface (positioning mechanism)
75P Positioning recess (positioning mechanism)
76 Fixed part 76A Eccentric cam (adapter pressing mechanism)
76B Pressing member (adapter pressing mechanism)
C1, C2 Transfer device J1 to J5 Robot rotation axis J6 Gripping device rotation axis (virtual axis)
JU1, JU2, JU3 Gripping claw rotation axis M1 Gripping claw posture maintenance mechanism M2 Workpiece pushing mechanism M3 Positioning mechanism M4 Positioning mechanism M5 Adapter pressing mechanism R Robot S1, S2 Processing device V1 Virtual circle W Workpiece W1 to W4 Workpiece position ΔH , ΔR gap

Claims (5)

a plurality of claw units arranged along the circumferential direction of a virtual circle along the outer periphery of the workpiece to be gripped;
a drive device that simultaneously moves each of the claw units radially outward or radially inward of the virtual circle;
The gripper has a gripping claw rotation axis substantially parallel to the tangential direction of the virtual circle with respect to the claw unit, and is supported by the claw unit so as to be rotatable about the gripper rotation axis, and is supported on the inner diameter side of the virtual circle. a gripping claw that grips the workpiece with a gripping surface provided on the workpiece;
has
The claw unit is provided with a gripping claw posture maintaining mechanism,
The gripping claw posture maintaining mechanism includes:
It has an elastic member that can be deformed and restored.
When the gripping claws are not gripping the workpiece, the restored elastic member returns the rotational position of the gripping claws about the rotational axis of the gripping claws to a predetermined rotational position;
When the gripping claw is gripping the workpiece, the elastic member is deformed so that the gripping surface of the gripping claw is in contact with the workpiece gripped surface. allowing the gripping claw to pivot around the gripping claw rotation axis;
The claw unit is provided with a workpiece extrusion mechanism,
The workpiece extrusion mechanism is
When the claw unit is pressed against the workpiece along the direction of an imaginary axis perpendicular to the plane of the virtual circle before the workpiece is gripped by the gripping claws, the direction is opposite to the direction of the workpiece. It is pushed in the direction of being pushed,
pushing out the workpiece in a direction opposite to the pushed direction when the workpiece gripped by the gripping claw is released;
Workpiece gripping device. a plurality of claw units arranged along the circumferential direction of a virtual circle along the outer periphery of the workpiece to be gripped;
a drive device that simultaneously moves each of the claw units radially outward or radially inward of the virtual circle;
The gripper has a gripping claw rotation axis substantially parallel to the tangential direction of the virtual circle with respect to the claw unit, and is supported by the claw unit so as to be rotatable about the gripper rotation axis, and is supported on the inner diameter side of the virtual circle. a gripping claw that grips the workpiece with a gripping surface provided on the
has
The claw unit is provided with a gripping claw posture maintaining mechanism,
The gripping claw posture maintaining mechanism includes:
It has an elastic member that can be deformed and restored.
When the gripping claws are not gripping the workpiece, the restored elastic member returns the rotational position of the gripping claws about the rotational axis of the gripping claws to a predetermined rotational position;
When the gripping claw is gripping the workpiece, the elastic member is deformed so that the gripping surface of the gripping claw is in contact with the workpiece gripped surface. allowing the gripping claw to pivot around the gripping claw rotation axis;
Each of the claw units is
a movable part that moves radially outward or radially inward of the virtual circle by the drive device;
an adapter arranged to be sandwiched between the movable part and the fixed part;
the fixing part that fixes the adapter to the movable part;
has
the adapter is provided with the gripping claw;
Workpiece gripping device. The workpiece gripping device according to claim 1 ,
Each of the claw units is
a movable part that moves radially outward or radially inward of the virtual circle by the drive device;
an adapter arranged to be sandwiched between the movable part and the fixed part;
the fixing part that fixes the adapter to the movable part;
has
the adapter is provided with the gripping claw;
Workpiece gripping device. The workpiece gripping device according to claim 2 or 3 ,
The adapter includes:
An adapter side reference surface and a positioning recess are provided,
The movable part includes
A movable part-side reference surface that faces and contacts the adapter-side reference surface, and a ball plunger that fits into the positioning recess are provided,
The fixed part includes
an adapter pressing mechanism that presses and fixes the adapter against the movable part;
Workpiece gripping device. The workpiece gripping device according to claim 4 ,
The adapter pressing mechanism has an eccentric cam.
Workpiece gripping device.

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