JP2006026748A - Robot wrist mechanism and operation method of end effector fitted thereto - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent restriction on the operation of a robot due to the presence of a motor for driving a sixth shaft part, when it is unavoidable to dispose peripheral equipment or the like in the robot operation area. <P>SOLUTION: An end effector driving bed 7 is constructed by a separate part independent of a tilting arm 5, and a plurality of abutting surfaces 17A, 17B, 17C at equal distances from the center are formed in the periphery of an end effector mounting part 14 having upper and lower axes located to form one plane with a reference axis 2. The lower end of the tilting arm 5 is provided with a joint seat 5A where the abutting surfaces 17A, 17B, 17C can be seated, whereby at the time of changing the position of a motor loading part 15 for rotating an end effector to the tilting arm 5, the joint seat 5A is attached with the abutting surfaces 17B, 17C different from the active abutting surface 17A in the end effector mounting part 14, thereby shifting the end effector driving motor 9 to avoid interference with peripherals. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a robot wrist mechanism and an end effector operating method attached to the robot wrist mechanism, and more specifically, a tilting arm is supported at the tip of a rotating arm that rotates about a reference axis, and projects to the side at the lower end of the tilting arm. The present invention relates to a mechanism that can be rearranged to avoid an end effector drive base from interfering with surrounding objects, and a robot operation method in a rearranged form.

  An articulated arc welding robot generally has six axes, and superimposes the rotation, tilting, and turning of each axis to hold the welding torch in a desired posture, and its tip is aimed. Displace to position. FIG. 8A shows an example of the robot 30, and the six shaft portions shown in the robot 30 are as follows.

  They are a sixth shaft portion 7 for turning or rotating a welding torch (not shown) mounted in the direction of arrow 31, and a tilting arm 5 for supporting the sixth shaft portion in the direction of arrow 28 such as swinging. The fifth shaft portion 6 that provides the operation, the fourth shaft portion 33 that rotates the upper arm 3 provided with the fifth shaft portion at the tip in the direction of the arrow 32, and the non-extension of the upper arm 3 that often has a substantially horizontal posture. A third shaft portion 36 for rotating and raising the rotating portion 3A in the direction of arrow 35 with respect to the lower arm 34 tilting in an upright state, and a third shaft for tilting the lower arm 34 in the direction of arrow 38 with respect to the swivel base 37. This is a first shaft portion 41 for turning the biaxial portion 39 and the swivel base 37 horizontally as indicated by an arrow 40 on the base.

  In such a welding robot, the arm main body 3B of the upper arm 3 rotating around the fourth axis 2 may be unevenly distributed on either the left or right side. An example of such a form is also disclosed in JP-A-2002-370190. More specifically, the upper arm 3 is formed by a rotating portion mainly including a hollow drive shaft 3C and an arm main body 3B integrated therewith in addition to the non-rotating portion 3A.

  The arm main body 3B is located at the base end of the hollow drive shaft 3C centered on the fourth axis 2 when viewed from one side of the fourth axis 2, from the right hand in the example of FIG. 8A. It is offset to the right side and is extended along the fourth axis 2 in that state. The tip of the arm body 3B cantileverally supports a tilting arm 5 that tilts about a crossing axis 4 that is perpendicular to the fourth axis 2 and that is horizontal.

  The reason why such a cantilever offset type upper arm 3 is adopted is as follows. (1) As shown in FIG. 9B, a welding wire, welding power, shield air, and the like are supplied to the welding torch 42. For this reason, the one-wire power cable 16 that is indispensable is placed as much as possible on the fourth axis 2 as shown in the plane arrow of (a), and the cable touches or entangles another device or the like in the robot operation area. It is possible to reduce as much as possible.

  Further, (2) when the tilting arm 5 tilts with respect to the upper arm 3, the space is moved up and down to allow bending so that the one-wire power cable 16 protrudes upward or downward as shown in (b). (3) Since one space 44 is vacated as shown in FIG. 9A, it is easy to perform maintenance work for inspection and replacement of the one-wire power cable 16. It is done. Incidentally, in (b), the tilting arm 5 is shown in a standard vertical posture, but (a) is in a state where the tilting arm 5 is in a horizontal posture that is an extension of the upper arm 3. It is drawn.

  By the way, when the surrounding object 45 such as a device for holding a workpiece or another robot as shown in FIG. 10A exists in the operation area of the welding robot 30 and must be brought close to the upper arm 3 unfortunately. There is. When the arm body 3B of the cantilever offset type is adopted for the upper arm 3, if the touch of the surrounding object 45 occurs, the operation of the robot is out of the question or the surrounding object is shifted to an inconvenient position. And so on.

  A possible solution to this problem is to invert the upper arm 3 that can be rotated around the fourth axis 2 180 degrees from the state of FIG. 10 (a) to (b). It is. The prior literature described above discloses a left-right mishandling operation according to this kind of procedure. For example, rotation of about ± 180 degrees is allowed from the state before reversal and the state after reversal.

  By the way, if it is set to ± about 180 degrees, the tilting arm 5 and the sixth shaft portion 7 can be swung to a total of 360 degrees or more regardless of whether the rotation is to the left or right, giving any position to the welding torch. Because it can. In addition, although it does not explain in detail that it does not exceed about 180 degrees on one side, in order not to cause a large twist in the control cable and the one-wire power cable, they must be entangled with the arm and cannot move. This is to keep it.

  The control cables 10 and 11 for the motors 8 and 9 for driving the fifth shaft portion 6 and the sixth shaft portion 7 shown in FIG. The control cable covered with the protective tube 13 up to the vicinity of the connectors 24A and 24B including the slack portion 12 after reaching the shoulder 50 in the lower arm 34 is one of the flanges 29 at the front end of the hollow drive shaft 3C. It is passed through a drawer portion 29a formed by cutting out the portion (see also FIG. 11B).

  In some cases, the cable 49 may be secured by the clamp 49 in front of the lead-out portion 29a, so that the fluttering of the cable in the slack portion 12 when the upper arm rotates can be suppressed, and from the lead-out portion 29a to the connectors 24A and 24B, Consideration is made to reduce the damage to the cables 10 and 11 so that the influence of the rotation of the upper arm 3 is not significantly different from the left and right. Note that how to process and operate the control cable at the time of reversing the arm body 3B is not the subject of the present application and will not be described.

By the way, in FIG. 10A, the upper arm 3 is rotated 180 degrees in the direction of the arrow 32 around the fourth axis 2, and the sixth shaft 7 and the sixth axis drive which are upside down by the rotation. If the motor 9 is returned to the normal posture by tilting the tilt arm 5 in the direction of the arrow 28 by 180 degrees, it can be as shown in FIG. 10B (see also FIG. 8B). The extra space 46 is secured between the upper arm 3 and the surrounding object 45, but nevertheless, the separation distance _Ltw of the sixth shaft portion 7 with respect to the surrounding object (work holding device 45) is maintained. Can do. Of course, it is possible to bring it closer to the workpiece. In the above prior art, even if the arm body can be reversed, the motor of the sixth shaft portion cannot be reversed. Therefore, interference with surrounding objects may still be unavoidable. In the example of FIG. 10, it can be seen that the attachment and detachment with respect to the workpiece or the like is placed in a more flexible state, which is extremely convenient.

  Incidentally, as can be seen from FIG. 8, the positional relationship between the tilting arm 5 and the sixth shaft portion 7 does not change before and after the arm body 3B is reversed. This is because, as shown in FIG. 12, the shape is adjusted by a component 47 formed so that the fifth shaft portion 6, the tilting arm 5, and the sixth shaft portion 7 are integrated. An end effector drive base that projects laterally is formed as a sixth shaft portion 7 at the lower end of the tilt arm 5, and includes an end effector mounting portion 14 and an end effector rotation motor mounting portion 15.

  The molded base 47 has a sixth shaft driving motor 9 shown in FIG. 11, a motor cover 9A covering the sixth shaft driving motor 9, a welding torch 42 of FIG. 9B, a bracket 51 for mounting the same, FIG. The control cable 11A on the front end side connected to the connector 24B shown in FIG. Note that the end effector mounting portion 14 and the end effector rotating motor mounting portion 15 in this example are determined such that a line 48 connecting the respective centers is parallel to the fourth axis 2.

  The configuration just described is shown in FIG. 13A. However, as shown in FIG. 13B, when the tilting arm 5, the end effector mounting portion 14, and the motor mounting portion 15 are linearly arranged, As shown in (c), there is a case where it is desired to arrange the motor mounting portion 15 at a position opposite to (a). In any case, the center of the end effector mounting portion 14 passes the one-line power cable 16 (see FIG. 9B) with respect to the tilting arm 5, that is, the arm main body 3B (FIG. 8A). If the sixth shaft drive motor 9, that is, the motor cover 9A, touches a part of the workpiece or the like, it is changed to any other form in FIG. Is desired.

If the above-described base body 47 is an integral product of casting as shown in FIG. 12, it is necessary to prepare at least three types of molded products according to FIG. Even if there is not much demand when the welding torch operates in a substantially vertical position, the tilting arm 5 extends on the extended line of the fourth axis 2, that is, as shown in FIG. When the welding torch is advanced into the workpiece in a horizontal or close state, the presence of the end effector rotation motor mounting portion 15 may limit the operation of the robot. Either eliminate it. However, the burden is large in terms of cost and storage that three types must be held, and replacement is performed by using the control cable 11A that passes through the speed reducer axis of the fifth shaft portion 6 shown in FIG. The troublesome work of pulling out and disassembling and assembling the bearing mechanism portion in the arm body 3B that cantilever the fifth shaft portion is forced.
JP 2002-370190 A

  The present invention has been made in view of the above problems, and its purpose is based on the presence of a sixth shaft drive motor when surrounding objects such as a work holding device and a work are inevitably arranged in a robot operation area. In order not to impose restrictions on the operation of the robot, the replacement of the sixth axis part can be easily operated without requiring a special tool and without removing the motor, its speed reducer and control cable. Furthermore, there are provided a robot wrist mechanism and an end effector operating method attached to the robot wrist mechanism in which the sixth axis portion is removed even if the fifth axis portion and the tilting arm are left, and the robot can be easily made into five axes. That is.

  In the present invention, a tilting arm that tilts around a crossing axis perpendicular to the reference axis is supported at the tip of a rotating arm that rotates about a reference axis, and an end effector that projects sideways at the lower end of the tilting arm. A drive base is formed, and the end effector drive base is applied to a robot wrist mechanism including an end effector mounting portion and an end effector rotation motor mounting portion. Referring to FIG. 1, the end effector drive base 7 is composed of a separate part independent of the tilting arm 5, and the vertical axis 14 a placed so as to form a plane with the reference axis 2. A plurality of contact surfaces 17A, 17B, and 17C that are equidistant from the center are formed around the end effector mounting portion 14 that has At the lower end of the tilting arm 5, a joint seat 5A is formed on which the contact surfaces 17A, 17B, 17C can be seated. When the position of the end effector rotation motor mounting portion 15 relative to the tilting arm 5 is changed, the end effector is changed by replacing the contact surfaces 17B and 17C different from the current contact surface 17A in the end effector mounting portion 14 with the joint seat 5A. That is, the position of the drive motor 9 is changed so that interference with the surrounding object 45 (see FIG. 5) can be avoided.

  The invention of the end effector operating method is based on the following procedure. First, the end effector drive base 7 is configured as a separate part independent of the tilting arm 5, and the end effector mounting portion 14 having a vertical axis 14 a placed so as to form a plane with the reference axis 2 is sandwiched. The abutment surface 17B formed on a part of the periphery of the end effector mounting portion 14 is tilted so that the end effector rotation motor mounting portion 15 is disposed at a position facing the tilting arm 5 (see FIG. 4B). It is seated and fixed on a joint seat 5A formed at the lower end of the arm 5. In this state, the end effector can be advanced into a space with a small vertical gap in a state where the tilt arm 5 is extended in the direction of the reference axis 2 (see FIG. 5D).

  The end effector drive base is a separate part independent of the tilt arm, and a plurality of contact surfaces that are equidistant from the center are formed around the end effector mounting part. Even when seated on the seat, the vertical axis given to the end effector mounting portion is always kept at a position that forms one plane without shifting from the reference axis of the rotary arm. The laying from the rotating arm of the one-wire power cable to the end effector mounting portion through the fifth shaft portion is simplified, and the twisting burden of the one-wire power cable accompanying the operation of the rotating arm is minimized. Can do.

  The posture of the end effector drive base can be changed while leaving the fifth shaft portion and the tilting arm on the rotating arm. In that case, a special tool is not necessary, and the removal and installation of the sixth shaft part does not involve dismantling of the drive system such as the sixth shaft drive motor and the speed reducer, and is different from the current contact surface. By changing the surface to the joint of the tilt arm, the position of the sixth axis driving motor can be changed very easily. As a result, the operation of the robot is made smooth by preventing the workpiece or the like from interfering with a functional product existing in the vicinity of the welding torch as a tool. In any case, it is allowed to leave the control cable on the robot even during the change operation of the end effector drive base, and the wrong change mechanism is provided with a simple structure.

  Since a plurality of contact surfaces around the end effector mounting portion are provided, related functional products such as assisting the function of the end effector are mounted except for the contact surface attached to the joint arm of the tilt arm. It is also possible. That is, it is possible to easily improve the function of the robot without introducing a new attachment.

  Since the sixth shaft portion can be separated from the tilting arm, a robot that does not require the sixth shaft portion, that is, a six-axis robot can be made into five axes. For example, instead of a welding torch that requires rotation or swiveling, support a robot hand or other tool directly or indirectly using a joint seat and divert it to a simple motion robot with a tilt arm as a tool holder. Is also easier.

  In the end effector operation method, if the end effector rotation motor mounting portion is arranged at a position facing the tilt arm across the end effector mounting portion, the tilt arm is extended in the direction of the reference axis of the rotary arm. In this state, the end effector can be made to enter a space having a small vertical gap. Since the axis of the end effector rotation motor mounting part is usually arranged so as to extend vertically, it is possible to produce the advantage of face-to-face arrangement that was not adopted due to the increased burden of the cantilever structure. become.

  Hereinafter, a robot wrist mechanism and an end effector operating method attached to the robot wrist mechanism according to the present invention will be described in detail with reference to the drawings showing embodiments thereof. FIG. 3 is an upper half view of the 6-axis arc welding robot 1 to which the present invention is applied. The schematic configuration is as described above with reference to FIGS. 8, 9, and 11. In the present invention, the fourth axis 2 to be noted will be referred to as a reference axis. The upper arm 3 that rotates about the axis is called a rotary arm, and the arm body 3B that constitutes the upper arm 3 is located at the base end of the hollow drive shaft 3C that has the reference axis 2 as the center and is on one side of the reference axis (toward To the right).

  A tilting arm 5 that tilts around a cross axis 4 orthogonal to the fourth axis 2 is cantilevered at the tip of the arm body 3B. The intersecting axis is the fifth axis, and the control cables for the motors 8 and 9 that individually drive the fifth axis portion 6 and the sixth axis portion 7 for turning the welding torch provided before the fifth axis portion 6. 10 and 11 are laid so as to face each motor.

  Then, the slack avoiding loosening portion 12 at the time of rotation is left on a part of the outer periphery of the hollow drive shaft 3C so that the rotating arm 3 can rotate until it forms a required angle with respect to either the left or right direction. That is, a part of the control cable is covered with the protective tube 13, but is partially wound around the hollow drive shaft 3C before reaching the arm body 3B.

  Based on such a configuration, in the present invention, even if the reference posture of the rotary arm 3 is changed by 180 degrees, the extension path of the one-wire power cable (not shown) is not changed, and the work is fixed. The sixth shaft portion 7 attached to the tip of the arm main body 3B which is inverted 180 degrees from the reference posture can be prevented from interfering with the surrounding objects so that the interference with the surrounding robot objects such as a device can be avoided. The main purpose is to do so.

  An end effector drive base projecting sideways is formed at the lower end of the tilting arm 5 as a sixth shaft portion 7, which is composed of an end effector mounting portion 14 and an end effector rotation motor mounting portion 15. As already mentioned. Therefore, specifically speaking, when the position of the end effector rotation motor mounting portion 15 is changed with respect to the tilt arm 5, the end effector rotation motor mounting portion 15 can be attached to the tilt arm even if the direction of the end effector mounting portion 14 is changed. The end effector rotating motor mounting portion 15 tries to prevent interference with surrounding objects.

  By the way, the one-wire power cable is for feeding the welding wire and is indispensable together with the control cable used for power supply, braking, grounding, position speed torque control, sensor power, sensor data backup power supply, etc. It is a cable. Since the control cables 10 and 11 were mentioned a little in the background art section, the description thereof is omitted here. The single-wire power cable has a multi-layer structure to simultaneously supply a welding wire for arc welding, power for welding, and shielding gas. Therefore, this cable cannot be said to be highly flexible, and has sufficient rigidity to generate a force for twisting back when twisting acts. Accordingly, the one-wire power cable 16 (see FIG. 6 described later) is arranged along the longitudinal direction of the arm main body 3B of the upper arm 3.

  Incidentally, there is a coil liner at the center of the one-wire power cable that guides its welding wire and protects it from wrinkling. The coil liner functions as a conduit pipe, but a shielding gas flows on the outer periphery thereof, and this is guided to the welding torch by the hose. The outer periphery is covered with a conductive wire, and the entire cable is covered with an insulating coating.

  The present invention is intended to solve the technical problem in the sixth shaft portion into which the front end of the one-wire power cable is introduced. However, the laying of the one-wire power cable that dislikes unnecessary deformation is also considered. That is, as shown in FIG. 1, the end effector drive base 7 is configured as a separate part independent of the tilt arm 5. As can be seen from the molded product in FIG. 2, the tilting arm 5 is integrated with the fifth shaft portion 6, and the end effector mounting portion 14 and the end effector rotating motor mounting portion 15 are integrated. It is a casting that is a separate body.

The center of the end effector mounting portion 14 whose position is important even when the one-wire power cable is passed is always arranged directly below the fourth axis 2 as shown in FIG. Around the end effector mounting portion 14 having an axis 14a extending vertically through the center, a plurality of abutment surfaces 17A in the center as shown in FIG. 1 equidistant L _d, 17B, 17C are formed . The vertical axis 14a refers to the time when the tilting arm 5 is in a vertical posture, so that it forms a single vertical plane with the fourth axis 2, that is, the fourth axis. Consideration should be taken so as not to deviate from the left or right.

  A joint seat 5A on which a contact surface can be seated is formed at the lower end of the tilting arm 5. One of the contact surfaces is assigned to the joint seat, and a small screw or the like 18 inserted from behind the tilting arm 5 is used. It can be integrated. As can be seen from FIG. 2, for example, three contact surfaces are formed except for a portion connected to the end effector rotation motor mounting portion 15 and form 90 degrees with adjacent surfaces. If it does in this way, an appropriate combination body can be obtained as shown in FIG. At that time, if it is necessary to cover the control cable on the end effector mounting portion 14, a protective cover 43 having a different arc length shown in the lower left of FIG. In addition, the number of contact surfaces can be made larger than 3, and the angle formed with the adjacent surfaces can be freely selected. Furthermore, the joint seat and the contact surface may be viewed in a plan view in an arc shape so that a plurality of or continuous joint surfaces can be obtained.

  If the contact surfaces 17A, 17B, and 17C are provided with a reference hole 20 that facilitates positioning in addition to a small hole 19 for screwing as shown in FIG. 1, an emboss 21 formed on the joint seat 5A is provided. The accuracy and speed of the integrated work can be achieved by fitting. With such a configuration, when the position of the end effector rotation motor mounting portion 15 with respect to the tilting arm 5 is changed, the end effector mounting portion is replaced with an abutment surface different from the current abutment surface to the end seat. The effector driving motor 9 can be repositioned to avoid interference with surrounding objects.

  In FIGS. 4A and 4C, the end effector rotation motor mounting portion 15 is close to the tilting arm 5 in the case of (a) and (c), and the burden on the upper arm that cantilever the arm is small. However, in (b), since the end effector mounting portion 14 exists between the facing surfaces of the tilting arm 5, the end effector rotating motor mounting portion 15 moves away from the tilting arm 5. A large moment M acts on the fifth shaft portion 6 of the cantilever portion because the sixth shaft driving motor 9 and the speed reducer are positioned. That is, the twisting force exerted on the arm main body 3B (see FIG. 3) of the upper arm is increased.

  By the way, in the case of the integrally molded product illustrated in FIG. 12, a space 53 is intentionally provided between the tilt arm 5 and the end effector mounting portion 14. This is a consideration for facilitating the operation of forming the screw hole 23 for screwing the holder / mounting portion cover 22 (see FIG. 6) when inserting the one-line power cable into the end effector mounting portion 14. Drilling a hole for forming a vertically extending screw hole and subsequent tapping depend on a vertically lowered tool (not shown), but when the tilting arm 5 approaches or the fifth shaft portion 6 is overhanging, This is because the tool holder interferes.

  On the other hand, in FIG. 2, since it is a separate body, the above machining can be performed on the end effector drive base 7 independently of the tilting arm 5. Therefore, the space 54 secured between the tilt arm 5 and the end effector mounting portion 14 can be small and short. The advantage of the separate product having such a shape also acts to reduce the moment described above. As can be seen from this, it is technically significant to make the sixth shaft portion 7 independent as a component structure in at least two ways.

  By the way, as shown in FIG. 5A, the tilting arm 5 is normally in the vertical position or close to it as shown in FIG. When the tilting arm 5 is rotated in the direction of the arrow 25 and the direction is made to coincide with the extending direction of the arm main body 3B, the result is as shown in FIG. In this case, the motor 9 is likely to contact the surrounding object 45. When the arrangement relationship between the end effector rotating motor mounting portion 15 and the tilt arm 5 is as shown in FIG. 4C, interference between the motor 9 and the surrounding object 45 can be avoided as shown in FIG. 5C.

  Now, when the combination is as shown in FIG. 4B and the tilt arm 5 is raised 90 degrees, the result is as shown in FIG. 5D. In a state where the tilt arm is extended in the direction of the fourth axis 2, marginal spaces 26 </ b> U and 26 </ b> L are created above and below the tilt arm 5, although there is a point that the moment exerted on the upper arm increases. For example, a welding torch can be advanced only in the case of the form (d) to a space having a small vertical gap such as a box in which a workpiece is placed horizontally and the opening height thereof is low. Needless to say, the flexibility of the work will increase. Incidentally, in FIG. 5, the center of the end effector mounting portion 14 is kept at a distance A from the surrounding object 45 and is not different from the description in FIG. 10.

  As can be seen from FIG. 6, the contact surfaces 17B and 17C that do not face the tilting arm 5 are open. Therefore, although not shown, a functional product required for welding, for example, a pull feeder (wire pulling type feeding device). ) Can also be installed. FIG. 7 shows an example of conversion to a 5-axis robot 27 that does not use the sixth axis portion, taking advantage of the separate structure. (A) shows a simple work holding device or work transfer device with the robot hand 27a attached, and (b) shows a device equipped with a sealing device 27b. In any case, the 5-axis configuration is very simple, and the versatility as a robot can be enhanced.

  As can be seen from the above description, since the center of the end effector mounting portion is always maintained at a fixed position, the laying of the one-line power cable from the upper arm through the fifth shaft portion to the end effector mounting portion is simplified. Thus, the twisting burden accompanying the operation of the upper arm can be minimized. The posture of the end effector drive base can be changed while leaving the fifth shaft portion and the tilting arm on the upper arm, and a drive system such as a sixth shaft drive motor or a speed reducer is used to remove or install the sixth shaft portion. By replacing the contact surface different from the current contact surface with the joint of the tilting arm, the position of the sixth axis drive motor can be repositioned very easily without the need for a special tool. It becomes like this.

  The sixth axis driving motor is prevented from interfering with a workpiece or the like, and the robot can be operated smoothly and with a wide width. Even during the change operation of the end effector drive base, the control cable is left on the robot, and the trouble of changing the wrong hand is greatly reduced. Since there are multiple contact surfaces around the end effector mounting part, the robot functions by attaching related functional products to the unused contact surfaces without the need for new accessories, accessories, or attachments. A great effect is exhibited, for example, it becomes easy to improve the above.

The perspective view showing the combination of the component from the upper arm of the welding robot to which the robot wrist mechanism which concerns on this invention was applied to the welding torch drive part. FIG. 3 is a perspective view showing a molded product of a tilt arm and a molded product of an end effector drive base molded independently of the tilted arm, and showing a base of each part. The perspective view of the upper half part of the welding robot with which the shaping | molding base | substrate was given and equipped. The perspective view of three examples at the time of changing an end effector drive base with respect to a tilting arm. The figure explaining the interference with the motor and surroundings at the time of making a tilting arm into a horizontal attitude | position, and its extent. The whole perspective view assembled as a welding robot. The perspective view of two examples at the time of setting it as a 5-axis robot. FIG. 3A is a perspective view of an upper arm in an initial state, and FIG. 2B is a perspective view of a state after 180 degrees of reversal in an installation state of an example of a welding robot. The wrist mechanism which consists of the upper arm which showed the hollow drive shaft part of the welding robot in the cross section, the tilting arm, and the 6th axial part is represented, (a) is a top view, (b) is a front view. This represents a state in which a work holding device or the like is close to the side of the upper arm, (a) is a plan view of the arm body in a state where the possibility of interference is extremely high, and (b) is a state in which the possibility of interference is eliminated by a reversing operation. The top view of the arm main body. The laying state of the control cable in an upper arm is represented, (a) is a perspective view explaining connection with each motor side connector, (b) is a single perspective view of a hollow drive shaft. The perspective view of the base | substrate produced by integrally molding a 5th axial part, a tilting arm, and a 6th axial part. The perspective view of the combined body of the tilting arm and 6th axial part which should be prepared in order to change the position of the 6th axis drive motor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Arc welding robot, 2 ... 4th axis (reference axis), 3 ... Upper arm (rotation arm), 3B ... Arm main body, 3C ... Hollow drive shaft, 4 ... Cross axis, 5 ... Tilt arm, 5A ... Joint seat , 6 ... 5th shaft portion, 7 ... 6th shaft portion (end effector drive base), 8, 9 ... motor, 14 ... end effector mounting portion, 14a ... vertical axis, 15 ... end effector rotation motor mounting portion, 17A , 17B, 17C ... contact surface, 27 ... 5-axis robot, 45 ... surrounding objects.

Claims (2)

A tilting arm that tilts around a crossing axis perpendicular to the reference axis is supported at the tip of a rotating arm that rotates around the reference axis, and an end effector drive base that projects sideways is formed at the lower end of the tilting arm. The end effector drive base is a robot wrist mechanism comprising an end effector mounting portion and an end effector rotation motor mounting portion.
The end effector drive base is configured as a separate part independent of the tilt arm, and is equidistant from the center around the end effector mounting portion having a vertical axis placed so as to form a plane with the reference axis. A plurality of contact surfaces are formed,
A joining seat capable of seating the contact surface is formed at the lower end of the tilt arm,
When changing the position of the end effector rotation motor mounting portion relative to the tilt arm, the end effector drive motor is repositioned by changing the contact surface different from the current contact surface in the end effector mounting portion to the joint seat. Robot wrist mechanism characterized by avoiding interference with objects. A tilting arm that tilts around a crossing axis perpendicular to the reference axis is supported at the tip of a rotating arm that rotates around the reference axis, and an end effector drive base that projects sideways is formed at the lower end of the tilting arm. The end effector drive base is an end effector operating method in a robot wrist mechanism comprising an end effector mounting portion and an end effector rotation motor mounting portion.
The end effector drive base is composed of separate parts independent of the tilt arm,
Around the end effector mounting part, the end effector rotation motor mounting part is arranged at a position facing the tilting arm across the end effector mounting part having a vertical axis placed so as to form a plane with the reference axis. The abutment surface formed on a part of the seat is seated and fixed on a joint seat formed at the lower end of the tilt arm,
An end effector operating method in a robot wrist mechanism, wherein an end effector can be entered into a space having a small vertical gap in a state where a tilt arm is extended in the direction of the reference axis.

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