Robotic Device

Abstract

To reduce an occupied space of an effector in a robot device which includes a drive section driving a processing section to relatively move to a robot and increases / decreases pressurizing force by the drive section.SOLUTION: In a drive section of a robot device, a rotary hollow shaft 7a of a hollow motor 7 has a hollow 12 which is coaxial with a rotation center, rotates around the rotation center, and has an axial direction one side of the hollow 12 opened to the outside. A screw shaft section 8a of a ball screw 8 is stored in the hollow 12 coaxially with the rotary hollow shaft 7a and is fastened to the rotary hollow shaft 7a. A processing section forms an integral article with a nut section 8b or the like of the ball screw 8, and relatively moves in an axial direction with respect to a robot on the axial direction one side of the rotary hollow shaft 7a, The rotary hollow shaft 7a is fastened to the screw shaft section 8a by a power lock 14 in the hollow motor 7.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a robot device that includes a processing unit that performs a predetermined process while exerting a force on a workpiece as an effector of the robot. [Background technology]

[0002] Conventionally, in a robot device such as the one described above, a configuration including a drive unit that increases or decreases the force that the processing unit applies to a workpiece by driving the processing unit to move relative to the robot has been known (see, for example, Patent Document 1). In the following description, the force that the processing unit applies to a workpiece may be referred to as the "pressure force."

[0003] More specifically, according to the conventional robot device 100, the driving unit 101 includes a servo motor 102, a ball screw 103, and a slide mechanism 104. That is, the servo motor 102 generates a rotational force for moving the processing unit 105 relative to the robot 106, and the ball screw 103 converts the rotational force generated by the servo motor 102 into a linear force and transmits it to the processing unit 105. In addition, the slide mechanism 104 has a guide unit 104a fixed to the robot 106, and a slide unit 104b that can move linearly relative to the guide unit 104a (see FIG. 4).

[0004] Furthermore, the processing section 105, the nut section 103a of the ball screw 103, and the slide section 104b are integrated to form an integrated part 110. With this configuration, the integrated object 110 including the processing portion 105 is linearly driven by the rotational force generated by the servo motor 102. Furthermore, the quality of the processed workpiece can be improved by increasing or decreasing the pressure force by controlling the energization of the servo motor 102.

[0005] However, in such a robot device 100, the amount of space occupied by the effector is considered to be an issue. For example, if the output shaft 102a of the servo motor 102, the screw shaft portion 103b of the ball screw 103, and the processing portion 105 are connected in series, the effector as a whole becomes longer in the direction of the center of rotation of the servo motor 102 (see FIG. 4(a)).

[0006] Furthermore, when the servo motor 102 and the ball screw 103 are connected in series, it is necessary to use a fastening part 112 such as a coupling to fasten the output shaft 102a and the screw shaft part 103b. This requires additional space for the fastening part 112, and furthermore, the overall length becomes longer in the direction of the rotation center.

[0007] In contrast to this, it is also possible to attach pulleys 113, 114 to the output shaft 102a and the screw shaft portion 103b, respectively, and mechanically connect the output shaft 102a and the screw shaft portion 103b in a direction perpendicular to the center of rotation of the servo motor 102 (see Figure 4(b)).

[0008] According to such an embodiment, the length of the servo motor 102 in the direction of the center of rotation can be reduced, but the servo motor 102 and the row of ball screws 103 and processing units 105 are arranged in parallel, which results in a larger occupied space in the direction perpendicular to the center of rotation of the servo motor 102. Therefore, in the robot device 100 equipped with the drive unit 101, a new aspect is required that can reduce the space occupied by the effector. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2018-187716 A Summary of the Invention [Problem to be solved by the invention]

[0010] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to reduce the space occupied by an effector in a robot device that has a drive unit that drives a processing unit to move relative to the robot and increases or decreases the pressure force using the drive unit. [Means for solving the problem]

[0011] The robot device of the present disclosure includes, as effectors of the robot, a processing unit and a driving unit as follows: the processing unit performs a predetermined process while exerting a force on a workpiece, and the driving unit drives the processing unit to move relative to the robot, thereby increasing or decreasing the force that the processing unit exerts on the workpiece.

[0012] The drive unit includes a hollow motor, a ball screw, and a slide mechanism. The hollow motor generates a rotational force for moving the processing unit relative to the robot, has a hollow shaft that is coaxial with the center of rotation and rotates around the center of rotation, and at least one side of the hollow shaft in the direction of the center of rotation is open to the outside. The ball screw has a screw shaft portion that is accommodated in the hollow coaxially with the rotating hollow shaft and is fastened to the rotating hollow shaft, and converts the rotational force generated by the hollow motor into a linear force and transmits it to the processing unit.

[0013] Furthermore, the slide mechanism has a guide portion fixed to the robot and a slide portion that can move linearly relative to the guide portion, and the movement direction of the slide portion coincides with the direction of the rotation center. The processing section forms an integral part with the nut section and slide section of the ball screw, and moves relative to the robot in the direction of the center of rotation of the rotating hollow shaft on one side of the direction of the center of rotation, and the rotating hollow shaft and the screw shaft section are fastened by a power lock inside the hollow motor. As a result, according to the present disclosure, it is possible to potentially reduce the space occupied by the effector in a robot device that increases or decreases the pressure force using a drive unit. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a configuration diagram of a robot device (embodiment); [Diagram 2] FIG. 11 is an explanatory diagram showing a state in which a hollow opening of a hollow motor is surrounded by a base and a slide mechanism (embodiment); [Diagram 3] FIG. 2 is an explanatory diagram showing a power lock that fastens a rotating hollow shaft and a threaded shaft portion, and a bearing for the rotating hollow shaft (Example). [Figure 4] FIG. 1(a) is a configuration diagram of a robot device in which a servo motor, a ball screw, and a processing unit are connected in series, and FIG. 1(b) is a configuration diagram of a robot device in which a servo motor, a ball screw, and a row of processing units are arranged in parallel (conventional example). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The robot device according to the embodiment will be described based on the following examples. EXAMPLES

[0016] [Configuration of the embodiment] The configuration of a robot device 1 according to an embodiment will be described with reference to FIGS. The robot device 1 includes, for example, a multi-joint robot 2 having multiple effectors at its tip, and a control unit 3 that controls the effectors and the robot 2, and controls the robot 2 to move the effectors in three dimensions while controlling the effectors to perform a predetermined process on a workpiece (not shown).

[0017] The robot device 1 also includes a processing unit 4 and a driving unit 5 as effectors of the robot 2. That is, the processing unit 4 performs a predetermined process while exerting a force on the workpiece, and the driving unit 5 drives the processing unit 4 to move relative to the robot 2, thereby increasing or decreasing the force (pressure force) that the processing unit 4 exerts on the workpiece.

[0018] Here, the processing unit 4 in the embodiment is, for example, a hem roller that performs hemming on the workpiece (hereinafter, the processing unit 4 may be referred to as the hem roller 4). The robot device 1 controls the operation of the robot 2 to move the hem roller 4 three-dimensionally, and performs hemming on the workpiece.

[0019] The drive unit 5 also includes a hollow motor 7, a ball screw 8, a slide mechanism 9, and a base 10. First, the hollow motor 7 generates a rotational force for moving the hem roller 4 relative to the robot 2, and has the following rotating hollow shaft 7a. That is, the rotating hollow shaft 7a is a cylindrical body and has a hollow 12 coaxial with the rotation center of the hollow motor 7. The rotating hollow shaft 7a rotates around the rotation center and forms the rotor of the hollow motor 7 (hereinafter, the direction of the rotation center may be referred to as the axial direction).

[0020] Additionally, a body 7b serving as a stator of the hollow motor 7 is attached to the outer periphery of the hollow rotating shaft 7a. Furthermore, bearings 13 for the hollow rotating shaft 7a are attached between the hollow rotating shaft 7a and the body 7b at two locations spaced apart in the axial direction (see FIG. 3).

[0021] A permanent magnet and a coil are attached to the outer periphery of the hollow rotating shaft 7a and the inner periphery of the body 7b, respectively, between the two bearings 13. (The permanent magnet and the coil are not shown.) The hollow motor 7 generates a rotational force by the interaction between the magnetic field of the permanent magnet and the current flowing through the coil. In addition, one axial side of the hollow 12 is open to the outside of the hollow motor 7, and the other axial side of the hollow 12 is closed by a power lock 14, which is a fastening structure between the rotating hollow shaft 7a and the screw shaft portion 8a of the ball screw 8.

[0022] Next, the ball screw 8 has a screw shaft portion 8a and a nut portion 8b. First, the screw shaft portion 8a is housed coaxially with the rotating hollow shaft 7a in the hollow 12, and is fastened to the rotating hollow shaft 7a by a power lock 14 inside the hollow motor 7. Then, the ball screw 8 converts the rotational force generated by the hollow motor 7 into a linear force and transmits it to the hem roller 4. In addition, with respect to the axial direction, the range in which the bearing 13 on the other axial side is present overlaps with the range in which the power lock 14 is present (see FIG. 3).

[0023] The nut portion 8b is screwed onto the screw shaft portion 8a and is integrated with the slide portion 9a described below to restrict rotation, and is driven linearly in the axial direction when the screw shaft portion 8a rotates. As a result, the ball screw 8 converts the rotational force transmitted from the hollow motor 7 into a linear force and transmits it to the slide portion 9a, linearly driving the hem roller 4 integrated with the slide portion 9a. The robot device 1 controls the current flowing through the coil of the hollow motor 7 to move the hem roller 4 relative to the robot 2 in the axial direction via the ball screw 8, thereby increasing or decreasing the pressing force.

[0024] The nut portion 8b has a main body 8b1 in which balls (not shown) mainly circulate, and a bracket 8b2 that extends outward from the main body 8b1 and is used for fastening to other components. The length of the bracket 8b2 in a predetermined direction perpendicular to the center of rotation is greater than the diameter of the hollow 12. As the hem roller 4 moves axially relative to the robot 2, the bracket 8b2 moves axially outside one axial side of the hollow 12 without entering the hollow 12. A portion of the main body 8b1 that is on the other axial side of the bracket 8b2 moves in and out of the hollow 12.

[0025] Next, the slide mechanism 9 has a guide part 9b fixed to the tip of the robot 2, and a slide part 9a that can move linearly relative to the guide part 9b. Here, the guide part 9b has a groove 15 that extends linearly, and the slide part 9a has a linear rail 16 that fits into the groove 15. Also, the guide part 9b is assembled to the robot 2 so that the movement direction of the slide part 9a coincides with the axial direction.

[0026] The hem roller 4, the nut portion 8b and the slide portion 9a are integrated to form an integrated body 18, which moves axially relative to the robot 2 due to the rotational force generated by the hollow motor 7 (see FIG. 1).

[0027] Furthermore, the integrated member 18 has a support body 19 and an intermediate body 20 in addition to the hem roller 4, the nut portion 8b, and the slide portion 9a, and the nut portion 8b and the slide portion 9a are integrated with the hem roller 4 via the support body 19 and the intermediate body 20. Here, the support body 19 holds the hem roller 4 rotatably. Furthermore, the support body 19, bracket 8b2, and the slide portion 9a are fastened to the intermediate body 20.

[0028] The hollow motor 7 is mounted on the base 10 and is fixed to the robot 2. The base 10 is, for example, U-shaped, with the two ends of the U fixed to the end of the robot 2 and the hollow motor 7 mounted on the bottom of the U. One axial side of the hollow motor 7 is fixed to the base 10 (see FIG. 1). When viewed from one axial side, the opening of the hollow 12 appears to be surrounded by the base 10 and the slide mechanism 9 (see FIG. 2).

[0029] Furthermore, when the integrated object 18 is located at the other end in the axial direction, the range in which the base 10 exists overlaps with the range in which the bracket 8b2 exists in the axial direction. In other words, when the pressure force is not increased by the driving unit 5, the range in which the base 10 exists overlaps with the range in which the bracket 8b2 exists. Note that both Figs. 1 and 3 show a state in which the driving unit 5 is operated to slightly increase the pressure force.

[0030] [Effects of the embodiment] The robot device 1 of the embodiment includes a processing unit 4 and a driving unit 5 as effectors of the robot 2. That is, the processing unit 4 performs a predetermined process while exerting a force on a workpiece, and the driving unit 5 drives the processing unit 4 to move relative to the robot 2, thereby increasing or decreasing the pressing force.

[0031] The driving unit 5 also has the following hollow motor 7, a ball screw 8, and a slide mechanism 9. That is, the hollow motor 7 generates a rotational force for moving the processing unit 4 relative to the robot 2, and has the following rotating hollow shaft 7a. That is, the rotating hollow shaft 7a has a hollow 12 coaxial with the rotation center and rotates around the rotation center, and one axial side of the hollow 12 is open to the outside.

[0032] The ball screw 8 converts the rotational force generated by the hollow motor 7 into a linear force and transmits it to the processing unit 4, and has the following screw shaft portion 8a. That is, the screw shaft portion 8a is accommodated in the hollow 12 coaxially with the rotating hollow shaft 7a and is fastened to the rotating hollow shaft 7a. Furthermore, the slide mechanism 9 has a guide portion 9b fixed to the robot 2, and a slide portion 9a that can move linearly relative to the guide portion 9b, and the movement direction of the slide portion 9a is the axial direction.

[0033] The processing unit 4 forms an integral part 18 with the nut portion 8b and slide portion 9a of the ball screw 8, and moves axially relative to the robot 2 on one axial side of the rotating hollow shaft 7a, and the rotating hollow shaft 7a and the screw shaft portion 8a are fastened together by a power lock 14 inside the hollow motor 7. This makes it possible to reduce the space occupied by the effector in the robot device 1 in which the pressure force is increased or decreased by the drive unit 5.

[0034] In other words, since the hollow rotating shaft 7a and the screw shaft portion 8a can be fastened inside the hollow motor 7, there is no need to provide additional space for fastening the output shaft 102a of the servo motor 102 and the screw shaft portion 103b, as in the conventional robot device 100 shown in Figure 4.

[0035] 4(a) in which a servo motor 102 and a ball screw 103 are connected in series, it was necessary to provide a space for a fastening portion 112 for fastening an output shaft 102a and a screw shaft portion 103b. However, according to the robot device 1 of the embodiment, such a space is not necessary, and the rotating hollow shaft 7a and the screw shaft portion 8a can be fastened inside the hollow motor 7. Therefore, the axial length of the effector as a whole can be reduced, and the space occupied by the effector can be reduced.

[0036] In addition, according to the conventional robot device 100, a flexible coupling was used in the fastening portion 112 to absorb axial misalignment between the output shaft 102a and the threaded shaft portion 103b, but the coupling had a large axial length and was contrary to the reduction of the space occupied by the effector. On the other hand, according to the robot device 1 of the embodiment, a power lock 14 with a small axial length is used in the fastening portion between the rotating hollow shaft 7a and the threaded shaft portion 8a, thereby further reducing the axial length.

[0037] Here, since the power lock 14 has a higher rigidity than the coupling, its ability to absorb axial misalignment is reduced. However, since the purpose of transmitting the torque from the hollow rotating shaft 7a to the threaded shaft portion 8a is to increase or decrease the pressure force, there is no need to rotate the hollow rotating shaft 7a at high speed in the first place. Therefore, even with a highly rigid power lock 14, the torque can be sufficiently transmitted from the hollow rotating shaft 7a to the threaded shaft portion 8a while absorbing axial misalignment. As described above, according to the robot device 1, by employing the power lock 14 as a fastening portion between the rotating hollow shaft 7a and the threaded shaft portion 8a, the space occupied by the effector can be further reduced.

[0038] According to the robot device 1 of the first embodiment, the nut portion 8b has a bracket 8b2 that is used to expand outward from the main body 8b1 to form the integral body 18, and the length of the bracket 8b2 in a predetermined direction perpendicular to the center of rotation is greater than the diameter of the hollow 12. As the processing portion 4 moves axially relative to the robot 2, the bracket 8b2 moves axially on one axial side outside the hollow 12, and the portion of the main body 8b1 that is on the other axial side of the bracket 8b2 moves in and out of the hollow 12. This makes it possible to suppress the expansion of the effector in a direction perpendicular to the axial direction, and also makes it possible to easily replace the ball screw 8.

[0039] When the bracket 8b2 is housed in the hollow 12, the axial length of the effector can be reduced, but it is necessary to increase the diameter of the hollow 12. As a result, it is necessary to increase the size of the hollow motor 7 as a whole in the radial direction, and the effector ends up expanding in the direction perpendicular to the axial direction. On the other hand, since the ball screw 8 is a consumable item that needs to be replaced, if the bracket 8b2 is present in the hollow 12, it cannot be easily replaced.

[0040] Therefore, the bracket 8b2 is mounted on the hollow motor 7 so as to be able to move axially outside one axial side of the hollow 12 without entering the hollow 12. The ball screw 8 is mounted on the hollow motor 7. This makes it possible to suppress the expansion of the effector in a direction perpendicular to the axial direction, and also makes it possible to easily replace the ball screw 8.

[0041] Furthermore, according to the robot device 1 of the embodiment, the range in which the power lock 14 exists and the range in which the bearing 13 of the hollow rotating shaft 7a exists overlap with each other in the axial direction. This makes it possible to stabilize the rotation of the screw shaft portion 8a.

[0042] Furthermore, according to the robot device 1 of the embodiment, the driving unit 5 has the following pedestal 10. That is, the hollow motor 7 is mounted on the pedestal 10 and is fixed to the robot 2. The pedestal 10 is fixed to one axial side of the hollow motor 7, and the opening of the hollow 12 is surrounded by the slide mechanism 9 and the pedestal 10 when viewed from one axial side. When the integrated object 18 is at the furthest other side in the axial direction, the range in which the pedestal 10 exists and the range in which the bracket 8b2 exists overlap in the axial direction. This allows the axial length of the effector as a whole to be further reduced, thereby further reducing the space occupied by the effector.

[0043] [Modifications] The embodiment discloses a specific example, and it goes without saying that the present invention is not limited to the embodiment. For example, according to the robot device 1 of the embodiment, the processing section 4 is the hem roller 4 that performs hemming on the workpiece, but the form of the processing section 4 is not limited to the hem roller 4. For example, the processing section 4 may be a polishing tool that polishes the surface of the workpiece. [Explanation of symbols]

[0044] REFERENCE SIGNS LIST 1 Robot device 2 Robot 4 Hemming roller (processing section) 5 Driving section 7 Hollow motor 7a Rotating hollow shaft 8 Boge screw 8a Screw shaft section 8b Nut section 9 Slide mechanism 9a Slide section 9b Guide section 12 Hollow 14 Power lock 18 Integrated section

Claims

1. As a robot effector, A processing section that applies a predetermined process to the workpiece while exerting a force thereon; a drive unit that drives the processing unit to move relative to the robot, thereby increasing or decreasing the force that the processing unit exerts on the workpiece, The drive unit is a hollow motor that generates a rotational force for moving the processing section relative to the robot, the hollow motor having a hollow shaft that has a coaxial center of rotation and rotates around the center of rotation, and at least one side of the hollow shaft in the direction of the center of rotation is open to the outside; A ball screw having a screw shaft portion that is accommodated coaxially with the rotating hollow shaft in the hollow and fastened to the rotating hollow shaft, converting a rotational force generated by the hollow motor into a linear force and transmitting the linear force to the processing unit; a slide mechanism including a guide portion fixed to the robot and a slide portion capable of moving linearly relative to the guide portion, the moving direction of the slide portion coinciding with the direction of the rotation center; the processing section forms an integral part with the nut section of the ball screw and the slide section, and moves relative to the robot in the direction of the rotation center on one side of the direction of the rotation center of the rotating hollow shaft; The robot device according to claim 1, wherein the hollow rotating shaft and the screw shaft portion are fastened to each other by a power lock inside the hollow motor.

2. 2. The robot device according to claim 1, The nut portion has a bracket extending outwardly from the body and utilized to form the integral body, The length of the bracket in a predetermined direction perpendicular to the rotation center is greater than the diameter of the hollow portion, a robot device characterized in that, as the processing unit moves relative to the robot in the direction of the center of rotation, the bracket moves in the direction of the center of rotation outside the hollow on one side of the direction of the center of rotation, and a portion of the main body that is on the other side of the direction of the center of rotation relative to the bracket moves in and out of the hollow.

3. 2. The robot device according to claim 1, a range in which the power lock exists and a range in which a bearing of the rotating hollow shaft exists overlap with each other in a direction of the center of rotation.

4. 3. The robot device according to claim 2, the driving unit has a base on which the hollow motor is mounted and which is fixed to the robot; The base is fixed to one side of the hollow motor in the direction of the rotation center, When viewed from one side in the direction of the rotation center, the hollow opening is surrounded by the base and the slide mechanism, a range in which the base exists and a range in which the bracket exists overlap in the direction of the rotation center when the integrated object is located on the other side in the direction of the rotation center.

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