Stopper structure and articulated robot

Abstract

To provide a stopper structure which can be installed even if a space is not sufficiently secured for a shaft etc. having a wide arm operation range and absorb a shear load preferably, and to provide a robot including the stopper structure.SOLUTION: A configuration of a stopper structure is a stopper structure 100a which restricts an arm 120 and a machine element (a base 110) from rotating by a predetermined angle or larger and includes: a projection 122 formed at one of the arm and the machine element; a hole 116 formed at the other of the arm and the machine element; and a stopper 140 which is inserted into the hole so as to be partially exposed from the hole. The stopper comprises: a block 150 formed of an elastic resin; and a surface layer metal plate 160 which is disposed along the front surface side, which contacts with the projection, of the surface of the block and has an angle shape cross section.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a stopper structure that restricts rotation of an arm and a mechanical element by a predetermined angle or more, and a multi-joint robot including the same.

Background Art

[0002] In a production site such as a factory, industrial robots (hereinafter referred to as multi-joint robots), such as robot arms (also referred to as manipulators), are used. Among multi-joint robots, particularly those that perform processing on a workpiece, the arm is fixed to the base or a plurality of arms are connected at joints (movable parts), and by operating the arm, processing such as picking and machining of the workpiece is performed.

[0003] For example, Patent Document 1 discloses "a robot stopping device provided with a stopper member provided on at least one of a pair of relative motion parts that move relative to each other, and when the pair of relative motion parts collide, the stopper member is sandwiched between the pair of relative motion parts to stop the relative motion". Specifically, the stopper member of the robot stopping device in Patent Document 1 is "a combined member in which at least two types of members having different hardnesses are fixed to each other, and both end faces of the member having a high hardness are directly in contact with each of the pair of relative motion parts, and are combined so as to receive the compression load at the time of collision of the pair of relative motion parts substantially perpendicularly at the both end faces".

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, with the increasing speed of articulated robot movements, the impact energy (load) generated when arms come into contact with the base or with other arms has also increased. For example, on axes with a wide range of motion, such as the J1 axis of an articulated robot, where the movement angle exceeds 340°, it is difficult to secure the necessary thickness and width in the direction of the compressive load, even if one attempts to absorb the energy with an elastic rubber stopper made of urethane or similar material, due to space constraints. Furthermore, even if only an elastic material is placed in a limited space, the dynamic load prevents the elastic material from withstanding the shear load and thus it will not function as a stopper.

[0006] In other words, for axes with a wide range of motion, such as the J1 axis, it was difficult to create a stopper structure that took advantage of the shock absorption benefits of elastic materials. Also, in postures with high inertia, such as a forward-leaning posture where kinetic energy is large, it was necessary to reduce the speed to protect structural members such as the stopper and arms.

[0007] Furthermore, while the stopper member described in Patent Document 1 can absorb compressive loads, it cannot absorb other loads, such as shear loads. Patent Document 1 states that the stopper members are provided on both sides of the base. However, in axes with a wide range of motion of the arm, if there is not enough space to place the stopper members, it may be difficult to place the stopper members adjacent to the base as described in Patent Document 1.

[0008] In view of these problems, the present invention aims to provide a stopper structure that can be installed even when sufficient space cannot be secured for axes and other components with a wide range of motion of the arm, and that can suitably absorb shear loads, and a multi-joint robot equipped therewith. [Means for solving the problem]

[0009] To solve the above problems, a typical configuration of the stopper structure according to the present invention is a stopper structure that restricts rotation of an arm and a mechanical element beyond a predetermined angle, and includes a projection formed on one of the arm or the mechanical element, a hole formed on the other of the arm or the mechanical element, and a stopper inserted into the hole such that a portion of the stopper is exposed from the hole, wherein the stopper is composed of a block made of elastic resin and a surface metal plate with an angle cross-section arranged along the front side of the surface of the block that contacts the projection.

[0010] The block described above may be a polygonal prism. The mechanical element described above may be the base or other arm of a multi-joint robot.

[0011] The device may further include a retaining plate that biases the stopper to prevent it from falling out of the stopper hole.

[0012] To solve the above problems, a typical configuration of the articulated robot according to the present invention is characterized by having the stopper structure described above. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a stopper structure that can be installed even when sufficient space cannot be secured for axes and other parts with a wide range of motion of the arm, and that can suitably absorb shear loads, as well as a multi-joint robot equipped therewith. [Brief explanation of the drawing]

[0014] [Figure 1] This is a perspective view illustrating the J1 axis of a multi-joint robot equipped with a stopper structure according to this embodiment. [Figure 2] This diagram illustrates the disassembled state of the stopper structure shown in Figure 1. [Figure 3] Figure 1 shows a top view and a side view of the articulated robot. [Figure 4] This is a cross-sectional view AA of Figure 3(a). [Figure 5] This is a cross-sectional view of BB in Figure 3(b). [Modes for carrying out the invention]

[0015] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific numerical values ​​shown in these embodiments are merely illustrative to facilitate understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to avoid redundant explanations, and elements not directly related to the present invention are omitted from the illustrations.

[0016] In the embodiment described above, an example in which the stopper structure according to the present invention is applied to the J1 axis of a multi-joint robot will be used for explanation. Specifically, the stopper structure shown in Figures 1-5 is a stopper structure that restricts rotation of the arm (mechanical element) and base (mechanical element) of the J1 axis of a multi-joint robot beyond a predetermined angle, and includes a projection formed on the arm, a hole formed on the base, and a stopper inserted into the hole such that a portion of the stopper is exposed from the hole, wherein the stopper is composed of a block made of elastic resin and a surface metal plate with an angle cross-section arranged along the front side of the surface of the block that contacts the projection.

[0017] Figure 1 is a perspective view illustrating the J1 axis of a multi-joint robot (hereinafter referred to as "robot 100") equipped with the stopper structure 100a according to this embodiment. Figure 2 is a diagram illustrating the disassembled state of the stopper structure 100a shown in Figure 1. Robot 100 is a multi-joint robot with 5 or 6 axes, but the J2 axis and beyond are omitted from the description as they are not necessary for explaining the invention. In the following embodiments, robot 100 will be described in detail with reference to the drawings, and the stopper structure 100a of this embodiment will also be described.

[0018] In this embodiment, the base 110 is exemplified as a mechanical element, but the present invention is not limited thereto, and the stopper structure according to the present invention may be applied to other joints such as the J2-J5 axes and J6 axis of the articulated robot. In that case, a stopper may be provided on one arm of the joint, and a hole may be provided in the other arm (mechanical element) to insert the stopper. Further, in this embodiment, an example is shown in which a protrusion is provided on the arm 120 and a stopper is disposed on the base 110. Conversely, a protrusion may be provided on the base 110 and a stopper may be disposed on the arm 120.

[0019] As shown in FIGS. 1 and 2, the robot of this embodiment includes a base 110 (mechanical element) and an arm 120. The base 110 is a member that fixes the robot 100 of this embodiment to a pedestal or the like (not shown). The arm 120 is pivotally supported by the base 110 and rotates with respect to the base 110.

[0020] FIG. 3 is a top view and a side view of the robot 100 shown in FIG. 1. FIG. 3(a) is a top view of the robot 100 shown in FIG. 2. FIG. 3(b) is a side view of the robot 100 shown in FIG. 2. FIG. 4 is a cross-sectional view taken along line A-A of FIG. 3(a).

[0021] As shown in FIGS. 3 and 4, the robot 100 of this embodiment includes a stopper structure 100a that restricts "rotation of the arm 120 with respect to the base 110 by a predetermined angle (see FIG. 5, for example, 170°) or more". The stopper structure 100a of this embodiment includes a protrusion 122 formed on the arm 120, a hole 116 formed in the base 110 which is a mechanical element, and a stopper 140 inserted into the hole 116 so that a part thereof is exposed from the hole 116.

[0022] The protrusion 122 is formed so as to protrude radially outward from the outer periphery 120a of the arm 120. In FIGS. 1-3, a state where the protrusion 122 is in an initial position (a position on the opposite side of the stopper structure 100a) is exemplified.

[0023] The base 110 is composed of a main body portion 112 and a mounting portion 114 that extends upward from the main body portion 112 (in the direction reaching the projection 122). In this embodiment, the mounting portion 114 is shown as part of the base 110, but it is not limited to this, and the mounting portion 114 may be a separate component from the base 110 and fixed with bolts.

[0024] The mounting portion 114 is a back support that supports the rear side of the block 150 (opposite side from the arm 120). The base 110 has a vertical hole 116 into which the stopper 140 is inserted (a hole perpendicular to the rotational direction of the projection 122). The hole 116 is on the arm 120 side of the mounting portion 114, with about half of it penetrating the mounting portion 114 and the remaining half protruding from the mounting portion 114 towards the arm 120.

[0025] The stopper 140 consists of a block 150 made of elastic resin and a surface metal plate 160 with an angle cross-section. The surface metal plate 160 is positioned along the front side (i.e., the side with the arm 120) of the surface of the block 150 that contacts the projection 122. The surface metal plate 160 does not cover the back side of the block 150, and there is no surface metal plate 160 interposed between the block 150 and the mounting portion 114.

[0026] Block 150 is a polygonal prism having a roughly triangular prism shape, for example, when viewed from the direction of insertion of block 150 into hole 116, with the front side formed in a convex shape. The entire stopper 140, along which the surface metal plate 160 is attached, is also a polygonal prism. The hole 116 also has an external shape that matches the shape of the stopper 140. As a result, even if a rotational moment force is generated in the stopper 140 when a shear load is applied from the contacting projection 122, the deformation of the surface metal plate 160 and block 150 effectively prevents the stopper 140 from rotating due to the moment force. In this embodiment, a roughly triangular prism (or, upon closer observation, a hexagonal prism with the corners of a triangular prism rounded off) block 150 is used as an example, but it is not limited to this, and block 150 may be a polygonal prism other than a triangular prism.

[0027] As shown in Figure 2, in this embodiment, the stopper structure 100a further includes a retaining plate 170 that biases the stopper to prevent the stopper 140 from falling out of the hole 116. As shown in Figure 4, the retaining plate 170 is attached to the mounting part 114 by a screw 180 after the stopper 140 is inserted into the hole 116 of the robot 100.

[0028] Figure 5 is a cross-sectional view of BB in Figure 3(b). Figure 5(a) illustrates the case where the projection 122 shown in Figure 1 is located on the opposite side (initial position) from the stopper 140. Figure 5(b) illustrates the case where the projection 122 shown in Figure 1 is located on the stopper 140 side (restricting position). In the robot 100 of this embodiment, the arm 120 is rotatable within a predetermined angle as shown in Figure 5(a), and rotation outside the predetermined angle is restricted by the projection 122 contacting the stopper 140 as shown in Figure 5(b).

[0029] In detail, when the arm 120 attempts to rotate beyond a predetermined angle and the projection 122 comes into contact with the stopper 140, the direction of the load on the contacting projection 122 is tangential to the circle of rotation (the outer circumference 120a of the arm 120). As a result, a shear load (a force that displaces an object parallel to itself; hereinafter referred to as shear load) acts on the stopper 140 that the projection 122 contacts.

[0030] In this embodiment, as in the stopper 140, the surface metal plate 160 is positioned on the front side of the block 150 that contacts the projection 122. Therefore, when a shear load is applied, the stopper 140 can absorb the impact by the elastic or plastic deformation of the surface metal plate 160. Furthermore, because the block 150 is positioned inside the surface metal plate 160, the block 150 deforms along with the plastic deformation of the surface metal plate 160, making it possible to absorb the shear load applied at the time of contact more efficiently. In other words, the kinetic energy of the arm 120 is absorbed by the energy of the plastic deformation of the surface metal plate 160 and the energy of the elastic deformation of the block 150.

[0031] If the stopper 140 were to consist only of an elastic resin block 150 without a surface metal plate 160, the block 150 would break due to shear load, making it impossible to absorb the impact upon contact. Furthermore, if a stopper made solely of elastic resin were used, the thickness and width of the stopper would need to be increased to obtain high impact absorption performance. In contrast, according to the robot 100 of this embodiment, the stopper 140, consisting of a block 150 and a surface metal plate 160, has high load absorption performance, allowing for a smaller volume compared to using a stopper made solely of elastic resin. Therefore, the stopper 140 can be positioned without space constraints, even on axes with a wide range of motion of the arm 120.

[0032] Furthermore, with the above configuration, due to its high shock absorption performance, it can adequately absorb shocks even in postures with high inertia, such as a forward-leaning posture, where kinetic energy is large, on axes with a wide range of motion, such as the J1 axis, where the operating angle exceeds 340°. As a result, there is no need to reduce speed to protect the stopper part, and it becomes possible to operate at high speed.

[0033] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to these examples. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention. [Industrial applicability]

[0034] The present invention can be used as a stopper structure that restricts rotation of an arm and a mechanical element beyond a predetermined angle, and as a multi-joint robot equipped therewith. [Explanation of Symbols]

[0035] 100...Robot, 100a...Stopper structure, 110...Base, 112...Main body, 114...Mounting part, 116...Hole, 120...Arm, 120a...Outer circumference, 122...Protrusion, 140...Stopper, 150...Block, 160...Surface metal plate, 170...Pressing plate, 180...Screw

Claims

1. A stopper structure that restricts rotation of an arm and a mechanical element beyond a predetermined angle, A projection formed on either the arm or the mechanical element, A hole formed in the arm or the other mechanical element, A stopper is inserted into the hole such that a portion of it is exposed from the hole, A retaining plate that biases the stopper to prevent it from falling out of the hole, and Includes, The stopper is, A block made of elastic resin, A surface metal plate with an angle cross-section is arranged along the front side of the surface of the block that contacts the protrusion, A stopper structure characterized by being composed of the following.

2. A stopper structure that restricts rotation of an arm and a mechanical element beyond a predetermined angle, A projection is formed so as to protrude radially outward from the outer circumference of the arm, The hole formed in the aforementioned mechanical element, A stopper is inserted into the hole such that a portion of it is exposed from the hole. Includes, The stopper is, A block made of elastic resin, A surface metal plate with an angle cross-section is arranged along the front side of the surface of the block that contacts the protrusion, A stopper structure characterized by being composed of the following.

3. The stopper structure according to claim 1 or 2, characterized in that the block is a polygonal prism.

4. The stopper structure according to any one of claims 1 to 3, characterized in that the mechanical element is the base or other arm of a multi-joint robot.

5. A multi-joint robot characterized by having a stopper structure according to claim 1 or 2.

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