Joint device for robot

Abstract

The present invention relates to a joint device for a robot, comprising: a first frame unit provided with a first hollow part; a second frame unit disposed so as to be spaced apart from the first frame unit, the second frame unit having a second hollow portion; a rotation shaft unit provided in each of the first hollow portion and the second hollow portion so as to be rotatable about a first axis, a second axis, and a third axis perpendicular to each other; a first link unit extending so as to surround the rotating shaft unit, connected to the first and second frame units via the rotating shaft unit, respectively, and provided so as to be rotatable about the first and second shafts; and a second link unit which extends around the rotating shaft unit in a state of crossing the first link unit, is connected to the first frame unit and the second frame unit via the rotating shaft unit, and is provided so as to be rotatable about the first shaft and the second shaft. The first link unit and the second link unit are each provided with a cam slider portion configured to correct a connection length between the first frame unit and the second frame unit when the second frame unit rotates relative to the first frame unit.

Description

Technical Field

[0001] The invention relates to a robot wrist joint device capable of realizing multi-degree-of-freedom motion. Background Art

[0002] Conventional multi-DOF robot joint devices are composed of multiple single-DOF joints including motors and reducers. As a result, the mass of the end portion increases, which reduces the payload (the maximum weight that the robot can lift and move), and increases the possibility of collision when interacting with people, which poses a dangerous problem.

[0003] In order to solve the above problems, existing patent 1 (Korean patent No. 10-1693250 (authorized on December 30, 2016)) and existing patent 2 (Korean patent No. 10-2009291 (authorized on August 5, 2019)) proposed placing a heavy motor and a part of the reducer at the base and a lightweight 3-DOF joint structure at the end, and using a cable drive.

[0004] This approach reduces the mass of the tip because the heavy motor is located at the base, which has the advantages of increased payload and improved safety when interacting with people. In addition, it overcomes the shortcomings of the traditional cable drive mechanism, thereby achieving a wide movable angle and low friction resistance.

[0005] However, this method has problems such as complex joint structure, low rigidity and durability due to distortion, and difficulty in assembly. Therefore, a new joint device is needed to solve these problems. Summary of the invention

[0006] A first object of the present invention is to provide a robot joint device that can realize a wide range of motion with three degrees of freedom and has a simpler joint structure.

[0007] A second object of the present invention is to provide a robot joint device that can accurately measure the rotation angle of a joint.

[0008] A third object of the present invention is to provide a robot joint device that has high torsional rigidity and is easy to wire.

[0009] A fourth object of the present invention is to provide a robot joint device that can solve the problems of sudden bending of cables, damage, errors, etc. caused by the cables in the existing cable driving method.

[0010] A fifth object of the present invention is to provide a robot joint device that can achieve yaw rotation using cables.

[0011] In order to achieve the first object of the present invention, the present invention discloses a joint device for a robot, comprising: a first frame unit having a first hollow portion; a second frame unit configured to be separated from the first frame unit and having a second hollow portion; a rotating shaft unit rotatably disposed in each of the first hollow portion and the second hollow portion around a first axis, a second axis, and a third axis perpendicular to each other; a first link unit extending in a manner surrounding the rotating shaft unit, connected to the first frame unit and the second frame unit respectively via the rotating shaft unit, and disposed to be rotatable around the first axis and the second axis; and The second connecting rod unit extends in a manner of encircling the above-mentioned rotating shaft unit in a state of crossing with the above-mentioned first connecting rod unit, is connected to the above-mentioned first frame unit and the second frame unit respectively via the above-mentioned rotating shaft unit, and is configured to be able to rotate around the above-mentioned first axis and the second axis. The above-mentioned first connecting rod unit and the second connecting rod unit respectively include a cam slider portion, and the cam slider portion is configured to correct the connection length between the above-mentioned first frame unit and the second frame unit when rotating for the above-mentioned rolling motion in such a manner that the above-mentioned second frame unit can perform a rolling motion relative to the virtual spherical surface relative to the above-mentioned first frame unit.

[0012] One end of the first link unit connected to the first frame unit and one end of the second link unit connected to the first frame unit may be arranged to be perpendicular to each other with the rotation axis unit as the center, and the other end of the first link unit connected to the second frame unit and the other end of the second link unit connected to the second frame unit may be arranged to be perpendicular to each other with the rotation axis unit as the center.

[0013] The cam slider portion may be provided at each of both ends of the first link unit and both ends of the second link unit.

[0014] The above-mentioned first connecting rod unit may include: a first cam, which is rotatable about the above-mentioned first axis and the second frame part; and a first connecting rod, which is rotatable about the above-mentioned second axis and is arranged on the above-mentioned first cam, and is configured to be able to move relative to the above-mentioned first cam by sliding movement. The above-mentioned second connecting rod unit may include: a second cam, which is rotatable about the above-mentioned second axis and the second frame part; and a second connecting rod, which is rotatable about the above-mentioned first axis and is arranged on the above-mentioned second cam, and is configured to be able to move relative to the above-mentioned second cam by sliding movement.

[0015] The above-mentioned cam slider portion may include: a pin hole and a cam groove formed in the above-mentioned first cam and the second cam; a hole and a groove formed in the above-mentioned first connecting rod and the second connecting rod; a connecting rod sliding member installed in the above-mentioned pin hole and formed to be able to move along the above-mentioned groove; and a cam sliding member installed in the above-mentioned hole and formed to be able to move along the above-mentioned cam groove.

[0016] In order to achieve the second purpose of the present invention, the robot joint device of the present invention also includes a detection unit, which is arranged on the above-mentioned first frame unit, the above-mentioned first cam and the second cam, and is configured to detect the rotation angle of the above-mentioned first link unit and the second link unit relative to the above-mentioned first axis and second axis.

[0017] The robot joint device of the present invention may further include another detection unit configured to detect the rotation of the rotation axis unit with respect to the third axis.

[0018] In order to achieve the third purpose of the present invention, the above-mentioned rotating shaft unit includes: an axis portion having an internal hollow shape; a first joint, having a hollow portion, which can be rotatably arranged at the two ends of the above-mentioned axis portion around the above-mentioned first axis; and a second joint, having a hollow portion, which can be rotatably connected to the above-mentioned first joint around the above-mentioned second axis, and can be rotatably arranged in the above-mentioned first hollow portion and the second hollow portion around the above-mentioned third axis.

[0019] In order to achieve the fourth object of the present invention, the robot joint device of the present invention further includes a driving unit configured to rotate the second frame unit relative to the first frame unit about the first axis and the second axis.

[0020] The driving part may include: a first cable unit, which is wound around the first pulley and passes through the first frame unit on both sides, and both ends are rotatably arranged in the second frame unit; and a second cable unit, which is wound around the second pulley and passes through the first frame unit on both sides, and both ends are rotatably arranged in the second frame unit, between the first frame unit and the second frame unit, both sides of the first cable unit are located on a first plane, and both sides of the second cable unit are located on a second plane perpendicular to the first plane.

[0021] The robot joint device of the present invention also includes a cable guide, which is arranged in the hole of the above-mentioned first frame unit and forms an opening for the above-mentioned first cable unit or the second cable unit to pass through. The inner side surface of the above-mentioned opening is provided with an arc portion convex toward the inside to guide the bending of the above-mentioned first cable unit and the second cable unit when the above-mentioned second frame unit rotates relative to the above-mentioned first frame unit.

[0022] The arc portion may include: an inner arc located adjacent to the rotation shaft unit; and an outer arc extending upward from the inner arc.

[0023] A location of the arc portion that protrudes most toward the inside of the opening may be arranged to be spaced apart in a direction farther from the second frame unit than first and second rotation axes of the rotation axis unit corresponding to the first and second axes.

[0024] In order to achieve the fifth object of the present invention, the present invention also includes a power transmission unit configured to transmit power to the above-mentioned rotating shaft unit, and the above-mentioned power transmission unit includes: a first conical pulley; a second conical pulley arranged perpendicular to the above-mentioned first conical pulley; a cable configured to be wound around the above-mentioned first conical pulley and the above-mentioned second conical pulley, and the second conical pulley is rotated by winding; and a power transmission shaft, which is combined with the above-mentioned second conical pulley and is configured to transmit rotational force to the above-mentioned rotating shaft unit.

[0025] In addition, the present invention discloses a joint device for a robot, comprising: a first frame unit having a first hollow portion; a second frame unit configured to be separated from the first frame unit and having a second hollow portion; a rotating shaft unit rotatably disposed in each of the first hollow portion and the second hollow portion around a first axis, a second axis and a third axis perpendicular to each other; a first connecting rod unit extending in a manner surrounding the rotating shaft unit, connected to the first frame unit and the second frame unit respectively via the rotating shaft unit, and configured to be rotatable around the first axis and the second axis; and a second connecting rod unit extending in a manner surrounding the rotating shaft unit in a state intersecting with the first connecting rod unit. The first frame unit and the second frame unit are respectively connected to each other via the rotating shaft unit, and are configured to rotate around the first and second axes; a first cable unit is configured to be wound around the first pulley and pass through the first frame unit on both sides, and both ends are rotatably arranged in the second frame unit; and a second cable unit is configured to be wound around the second pulley and pass through the first frame unit on both sides, and both ends are rotatably arranged in the second frame unit, between the first frame unit and the second frame unit, both sides of the first cable unit are located on a first plane, and both sides of the second cable unit are located on a second plane perpendicular to the first plane.

[0026] The robot joint device of the present invention may further include a cable guide, which is arranged in the hole of the above-mentioned first frame unit and is formed with an opening for the above-mentioned first cable unit or the second cable unit to pass through. The inner side surface of the above-mentioned opening may have an arc portion convex toward the inside to guide the bending of the above-mentioned first cable unit and the second cable unit when the above-mentioned second frame unit rotates relative to the above-mentioned first frame unit.

[0027] The effects of the present invention obtained by the above-mentioned solving means are as follows.

[0028] First, the first frame unit and the second frame unit are connected to a rotating shaft unit that can rotate on three axes, the first frame unit and the second frame unit are connected to rotate on two axes, and the first link unit and the second link unit are respectively provided with a cam slider portion configured to correct the connection length between the first frame unit and the second frame unit. Therefore, a robot joint device with a simpler joint structure can be provided in which the second frame unit can perform a wide movable range of three degrees of freedom by rolling motion relative to a virtual spherical surface relative to the first frame unit.

[0029] Second, by configuring the detection unit to detect the rotation angles of the first link unit and the second link unit relative to the first axis and the second axis and the rotation of the rotation axis unit relative to the third axis, the rotation angle of the joint can be accurately measured. When the joint device of the present invention is set at the wrist joint part of the robot, the above detection technology can be applied to more accurately control the drive of the wrist.

[0030] Third, by making the shaft of the rotating shaft unit have a larger outer diameter than before and forming a hollow shape, high torsional rigidity of the joint device can be ensured. In addition, the cable is configured to pass through the inside of the shaft and the first to third joints, thereby preventing the existing structure in which the cable is configured outside and the cable is twisted, stretched, and other problems that may be caused by the driving of the joint.

[0031] Fourth, by providing a cable guide on the first frame unit, the bending of the cable can be smoothly guided, and considering the difference in contact range between the cable guide and the cable, the inner arc and the outer arc have different designs, thereby minimizing the cable error caused by the above bending.

[0032] Fifth, by arranging the first bevel pulley and the second bevel pulley to be perpendicular to each other and linking them with a cable, a rotational force can be transmitted to the rotation shaft unit connected to the second bevel pulley, thereby realizing yaw rotation of the joint device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a conceptual diagram of a robot joint device according to an embodiment of the present invention.

[0034] Figure 2 Is a separate expression Figure 1 The figure of part A is a conceptual diagram shown after the frame cover of the second frame unit is removed.

[0035] Figure 3 It will constitute Figure 1The main components of Part A are separated and shown in an exploded view.

[0036] Figure 4 This is a conceptual diagram for explaining a 1-DOF rolling joint using a variable link.

[0037] Figure 5 (a) and (b) are conceptual diagrams for explaining a 2-DOF rolling joint using two variable links arranged perpendicular to a center link.

[0038] Figure 6 This is a conceptual diagram for explaining the one-degree-of-freedom rolling joint control using a cable.

[0039] Figure 7 This is a conceptual diagram for explaining the 2-DOF rolling joint control using cables.

[0040] Figure 8 yes Figure 3 An exploded perspective view of the cam slider portion is shown.

[0041] Fig. 9 (a) to (e) show Figure 2 A conceptual diagram showing the structural changes of the cam slider portion caused by the tumbling rotation of the second frame unit shown.

[0042] Fig.10 (a) to (d) show Figure 1 A conceptual diagram showing the structural changes of part A during yaw rotation of the hand.

[0043] Fig.11 (a) to (h) show Figure 2 The diagram is a conceptual diagram showing the structural changes of the A portion when the second frame unit performs a rolling motion (rolling and / or pitching rotation) relative to a virtual spherical surface.

[0044] Fig.12 yes Figure 1 A cross-sectional view of part A.

[0045] Fig.13 It is shown in Fig.12 The illustrated state is a conceptual diagram of a state in which the second frame unit performs a rolling motion (rolling and pitching rotation) with respect to a virtual spherical surface.

[0046] Fig.14 yes Figure 1 A cross-sectional view of a joint device for a robot is shown. DETAILED DESCRIPTION

[0047] Below, the embodiments disclosed in this specification are described in detail with reference to the accompanying drawings. Regardless of the figure numerals, the same or similar constituent elements are assigned the same figure numerals, and repeated descriptions thereof are omitted. The suffixes "module" and "unit" of the constituent elements used in the following description are only assigned or mixed for the convenience of writing the specification, and they themselves do not have meanings or functions that distinguish each other. In addition, when describing the embodiments disclosed in this specification, when the specific description of the relevant known technology is judged to be likely to confuse the gist of the embodiments disclosed in this specification, its detailed description is omitted. In addition, the drawings are provided only to make it easy to understand the embodiments disclosed in this specification. The technical ideas disclosed in this specification are not limited by the drawings, and should be understood to include all changes, equivalents and even substitutes within the scope of the ideas and technologies of the present invention.

[0048] Terms including ordinal numbers such as first, second, etc. may be used to describe a plurality of components, but the components are not limited to the above terms. The above terms are only used to distinguish one component from other components.

[0049] When a certain component is described as being “connected” or “accessed” to another component, it should be understood that it can be directly connected or accessed to the other component, or other components may exist in between. Conversely, when a certain component is described as being “directly connected” or “directly accessed” to another component, it should be understood that no other components exist in between.

[0050] An expression in the singular includes an expression in the plural unless the meaning is clearly different in the context.

[0051] In the present application, terms such as "including" or "having" should be understood as being used to specify the existence of features, numbers, steps, actions, constituent elements, parts or combinations thereof recorded in the specification, and should not be understood as excluding in advance the existence or additional possibilities of one or more other features or numbers, steps, actions, constituent elements, parts or combinations thereof.

[0052] Figure 1 is a conceptual diagram of a robot joint device 100 according to an embodiment of the present invention. Figure 2 Is shown separately Figure 1 The figure of part A is a conceptual diagram showing that the frame cover 122 of the second frame unit 120 is removed. Figure 3 It will constitute Figure 1 The main components of Part A are separated and shown in an exploded view.

[0053] Reference Figures 1 to 3The robot joint device 100 of the present invention can be applied to the wrist of a humanoid robot. The robot joint device 100 includes a first frame unit 110 , a second frame unit 120 , a rotation axis unit 130 , a first link unit 140 , a second link unit 150 , and driving parts 160 , 170 .

[0054] The first frame unit 110 includes a first hollow portion 110a. The first hollow portion 110a may be provided at the center of the first frame unit 110. The first frame unit 110 may be connected to a forearm frame extending from an elbow portion toward a wrist portion.

[0055] The second frame unit 120 is arranged to be separated from the first frame unit 110 and has a second hollow portion 120a. The second hollow portion 120a can be provided at the center of the second frame unit 120. In the reference state where the second frame unit 120 is arranged parallel to the first frame unit 110, the second hollow portion 120a is located at a position overlapping with the first hollow portion 110a along the separation direction (Z-axis direction in the figure).

[0056] The rotation axis unit 130 is rotatably provided in each of the first hollow portion 110a and the second hollow portion 120a around a first axis (X axis in the figure), a second axis (Y axis in the figure) and a third axis (Z axis in the figure) which are perpendicular to each other. The hand 101 may be provided in the second frame unit 120, and the hand 101 is configured to rotate around the third axis when the rotation axis unit 130 rotates around the third axis.

[0057] In this embodiment, the second frame unit 120 is shown to include a base frame 121 and a frame cover 122 that is relatively rotatable about a third axis relative to the base frame 121. The frame cover 122 is configured to rotate about the third axis when the rotation axis unit 130 rotates about the third axis, and the hand 101 is mounted on the frame cover 122.

[0058] The second frame unit 120 can rotate relative to the first frame unit 110 (roll and / or pitch rotation) around at least one of the first axis and the second axis through the rotation axis unit 130, and the frame cover 122 and the hand 101 mounted thereon can rotate relative to the base frame 121 around the third axis (yaw rotation). That is, the robot joint device 100 of the present invention has three degrees of freedom, which can rotate in the roll direction and the pitch direction (bending in form) and the yaw rotation of the distal end (hand 101).

[0059] In the present embodiment, the rotating shaft unit 130 is shown to be configured to include the shaft portion 131 , the first joint 132 , and the second joint 133 .

[0060] The shaft portion 131 may have a hollow interior. Such an empty space inside the shaft portion 131 may be used as a structure for wiring as described below. In the past, a shaft portion 131 having a small outer diameter and filled inside was used, but the shaft portion 131 of the present invention has a larger outer diameter than before and is formed into a hollow shape, thereby ensuring high torsional rigidity of the joint device 100.

[0061] The first connector 132 is rotatably connected to both ends of the shaft 131 around the first axis. To this end, both ends of the shaft 131 may have a "Y"-shaped branched shape. For wiring, the first connector 132 has a hollow portion inside.

[0062] The second joint 133 is rotatably connected to the first joint 132 about the second axis, and is rotatably provided in the first hollow portion 110a and the second hollow portion 120a about the third axis. For wiring, the second joint 133 may have a hollow portion inside.

[0063] For reference, in this figure, the rotation of the second frame unit 120 relative to the first frame unit 110 around the fourth axis that is inclined 45 degrees relative to the first axis is represented as roll, the rotation around the fifth axis that is inclined 45 degrees relative to the second axis is represented as pitch, and the rotation around the third axis is represented as yaw.

[0064] When the second frame unit 120 rotates relative to the first frame unit 110, the above rotation is realized by rolling motion relative to the virtual spherical surface. At this time, the virtual spherical surface is formed by a virtual hemisphere with a radius of 1 / 2 of the length of the rotation axis unit 130 on each of the first frame unit 110 and the second frame unit 120. The rolling motion will be described in detail later.

[0065] The first link unit 140 extends in a manner surrounding the rotation axis unit 130, and is connected to the first frame unit 110 and the second frame unit 120 respectively via the rotation axis unit 130. The first link unit 140 is rotatably provided on each of the first frame unit 110 and the second frame unit 120 around the first axis and the second axis. Both ends of the first link unit 140 respectively connected to the first frame unit 110 and the second frame unit 120 are arranged on a virtual first plane that crosses the rotation axis unit 130.

[0066] The second link unit 150 extends in a manner of encircling the rotation axis unit 130 in a state of crossing the first link unit 140, and is connected to the first frame unit 110 and the second frame unit 120 respectively via the rotation axis unit 130. The second link unit 150 is rotatably provided on each of the first frame unit 110 and the second frame unit 120 around the first axis and the second axis. Both ends of the second link unit 150 respectively connected to the first frame unit 110 and the second frame unit 120 are arranged on a virtual second plane that crosses the rotation axis unit 130 and is perpendicular to the virtual first plane.

[0067] One end of the first link unit 140 and one end of the second link unit 150 connected to the first frame unit 110 are arranged perpendicular to each other with the rotating shaft unit 130 as the center. One end of the first link unit 140 is rotatably provided on the first frame unit 110 with the first axis as the center, and one end of the second link unit 150 is rotatably provided on the first frame unit 110 with the second axis as the center.

[0068] The other end of the first link unit 140 connected to the second frame unit 120 and the other end of the second link unit 150 are arranged perpendicular to each other with the rotation axis unit 130 as the center. The other end of the second link unit 150 is rotatably provided on the second frame unit 120 with the first axis as the center, and the other end of the second link unit 150 is rotatably provided on the second frame unit 120 with the second axis as the center.

[0069] For reference, in this embodiment, a structure using two link units (the first link unit 140 and the second link unit 150 ) which are the minimum number for realizing a mechanism is shown in order to simplify the structure, but the present invention is not limited thereto.

[0070] In addition to the first link unit and the second link unit, one or two further link units may be provided. In this case, there is an advantage of improved strength and rigidity compared to the structure of the present embodiment.

[0071] As an example, in the case where a further link unit is provided, if the further provided link unit is named a third link unit, the third link unit may be configured to be symmetrical with the first link unit 140 or the second link unit 150 with the rotation shaft unit 130 as the center.

[0072] As another example, when two link units are further set, if the further set link units are named as the third link unit and the fourth link unit, the third link unit and the fourth link unit can be configured to be symmetrical with the first link unit 140 and the second link unit 150 respectively with the rotation axis unit 130 as the center.

[0073] The driving parts 160 and 170 are configured to rotate the second frame unit 120 about the first axis and the second axis relative to the first frame unit 110. That is, the driving parts 160 and 170 can cause the second frame unit 120 to roll and / or pitch relative to the first frame unit 110 to form a rolling motion relative to a virtual spherical surface.

[0074] The driving part 160 , 170 includes a first cable unit 160 and a second cable unit 170 .

[0075] The first cable unit 160 is wound around a first pulley (not shown). The first pulley may be provided at the elbow portion or the forearm portion. With the first pulley as a reference, both sides of the first cable unit 160 are connected to the second frame unit 120 through the first frame unit 110 and rotatably. In the present embodiment, the first cable unit 160 is configured to include a first cable 161 and a first coupler 162 coupled to both ends of the first cable 161, and the first coupler 162 is rotatably provided at the second frame unit 120 with the fourth axis and the fifth axis as the center. For reference, in a plane (XY plane) formed by the first axis and the second axis, the fourth axis is arranged at an angle of 45 degrees relative to the first axis, the fifth axis is arranged at an angle of 45 degrees relative to the second axis, and the fourth axis and the fifth axis are arranged perpendicularly relative to the third axis.

[0076] The second cable unit 170 is wound around a second pulley (not shown). The second pulley may be provided at the elbow portion or the forearm portion. With the second pulley as a reference, both sides of the second cable unit 170 are rotatably connected to the second frame unit 120 through the first frame unit 110. In the present embodiment, the second cable unit 170 is configured to include a second cable 171 and a second coupler 172 coupled to both ends of the second cable 171, and the second coupler 172 is rotatably provided at the second frame unit 120 with the fourth axis and the fifth axis as the center.

[0077] However, the present invention is not limited thereto. The first coupler 162 and the second coupler 172 may be formed in a spherical shape and may be rotatably mounted on a socket of the second frame unit 120 .

[0078] Between the first frame unit 110 and the second frame unit 120 , both sides of the first cable unit 160 are located on a first plane, and both sides of the second cable unit 170 are located on a second plane perpendicular to the first plane.

[0079] On the other hand, the first link unit 140 and the second link unit 150 are respectively provided with a cam slider portion so as to correct the connection length between the first frame unit 110 and the second frame unit 120 when the second frame unit 120 rotates relative to the first frame unit 110 to form a rolling motion relative to the virtual spherical surface.

[0080] The cam slider portion may be provided at least one of the two ends of the first link unit 140 and at least one of the two ends of the second link unit 150. In this embodiment, the cam slider portions are provided at both ends of the first link unit 140 and both ends of the second link unit 150, respectively, so that rolling motion can be simulated by more precise connection length correction.

[0081] As described above, the first frame unit 110 and the second frame unit 120 are connected to a rotating shaft unit 130 so as to be rotatable in three axes, the first frame unit 110 and the second frame unit 120 are connected to be rotatable in two axes, and the first link unit 140 and the second link unit 150 are respectively provided with a cam slider portion configured to correct the connection length between the first frame unit 110 and the second frame unit 120. Therefore, a robot joint device 100 with a simpler joint structure can be provided in which the second frame unit 120 can perform a rolling motion relative to a virtual spherical surface with a wide movable range of three degrees of freedom relative to the first frame unit 110.

[0082] Hereinafter, the above-mentioned rolling motion and the structure realizing the same are explained in more detail.

[0083] Figure 4 This is a conceptual diagram for explaining a 1-DOF rolling joint using a variable link. Figure 5 (a) and (b) are conceptual diagrams for explaining a 2-DOF rolling joint using two variable links arranged perpendicular to a center link.

[0084] First, refer to Figure 4 The rotation axis unit 130 is connected to a center C of a surface of the first frame unit 110 and a center C of a surface of the second frame unit 120. It is assumed that a virtual semicircle 110', 120' with a radius of 1 / 2 of the length d of the rotation axis unit 130 is formed on a surface of the first frame unit 110 and a surface of the second frame unit 120, respectively.

[0085] At this time, the virtual semicircle 120' formed in the second frame unit 120 performs rolling motion, that is, rotates without sliding, in a state of contact with the virtual semicircle 110' formed in the first frame unit 110. In order to simulate such rolling motion, the link units 140 and 150 are connected to a position E eccentric from the center of one surface of the first frame unit 110 and a position E eccentric from the center of one surface of the second frame unit 120. When the first frame unit 110 and the second frame unit 120 are arranged to face each other, both ends of the link units 140 and 150 respectively connected to the first frame unit 110 and the second frame unit 120 are located on one side and the other side, that is, in the diagonal direction, with the rotation axis unit 130 as a reference.

[0086] At this time, in order to make the link units 140 and 150 accurately simulate the rolling motion, the link units 140 and 150 are configured to have variable lengths L and L'. That is, by calibrating the link units 140 and 150 to the optimal lengths L and L' according to the rotation axis unit 130 and the rolling motion angle, the second frame unit 120 can perform rolling motion relative to the first frame unit 110 relative to the virtual semicircles 110' and 120'.

[0087] If this 1-DOF rolling joint structure is expanded to a 2-DOF rolling joint structure, then Figure 5 As shown in (a) and (b). Figure 5 In (a) and (b), the rotation axis unit 130 is connected to the center of one surface of the first frame unit 110 and the center of one surface of the second frame unit 120. It is assumed that one surface of the first frame unit 110 and one surface of the second frame unit 120 are respectively formed with virtual hemispheres 110' and 120' with a radius of 1 / 2 of the length d of the rotation axis unit 130.

[0088] At this time, the virtual hemisphere 120' formed in the second frame unit 120 rolls, that is, rotates without sliding, in a state of contact with the virtual hemisphere 110' formed in the first frame unit 110. In order to simulate such rolling motion, the first link unit 140 and the second link unit 150 connected to the first frame unit 110 and the second frame unit 120 and arranged to cross each other are provided around the rotation axis unit 130.

[0089] One end of the first link unit 140 and one end of the second link unit 150 connected to the first frame unit 110 are configured to be perpendicular to each other with the rotating shaft unit 130 as the center, and the other end of the first link unit 140 and the other end of the second link unit 150 connected to the second frame unit 120 are configured to be perpendicular to each other with the rotating shaft unit 130 as the center.

[0090] When the first frame unit 110 and the second frame unit 120 are arranged to face each other, both ends of the first link unit 140 and the second link unit 150 respectively connected to the first frame unit 110 and the second frame unit 120 are located on one side and the other side, i.e., in the diagonal direction, with the rotation axis unit 130 as a reference.

[0091] At this time, in order to make the first link unit 140 and the second link unit 150 accurately simulate the rolling motion, the first link unit 140 and the second link unit 150 are configured in a variable length manner. That is, the second frame unit 120 can perform a rolling motion relative to the virtual hemispheres 110', 120' relative to the first frame unit 110 by calibrating the first link unit 140 and the second link unit 150 to the optimal length according to the rotation axis unit 130 and the rolling motion angle.

[0092] Figure 6 This is a conceptual diagram for explaining the 1-DOF rolling joint control using a cable. Figure 7 This is a conceptual diagram for explaining the 2-DOF rolling joint control using cables.

[0093] First, refer to Figure 6 , the front Figure 4 The 1 DOF rolling joint can utilize a cable to control the movement.

[0094] Specifically, the cable is wound around a pulley, and when the pulley rotates in one direction, one side of the cable becomes shorter and the other side becomes longer. On the contrary, if the pulley rotates in the other direction, one side of the cable becomes longer and the other side becomes shorter. At this time, the length shortened by winding around the pulley is the same as the length lengthened by unwinding from the pulley.

[0095] Next, one side of the cable is passed through one end of a semicircle with a radius of r=d / 2 formed in the first frame unit 110, and fixed to one end of a semicircle with a radius of r=d / 2 formed in the second frame unit 120. At this time, the length of the cable connecting one end of the semicircle formed in the first frame unit 110 and one end of the semicircle formed in the second frame unit 120 is defined as T1.

[0096] In addition, the other side of the cable is passed through the other end of the semicircle with a radius of r=d / 2 formed in the first frame unit 110, and is fixed to the other end of the semicircle with a radius of r=d / 2 formed in the second frame unit 120. At this time, the length of the cable connecting the other end of the semicircle formed in the first frame unit 110 and the other end of the semicircle formed in the second frame unit 120 is defined as T2.

[0097] According to the above configuration, when the pulley rotates in one direction, one side of the cable becomes shorter, and one end of the semicircle formed in the first frame unit 110 and one end of the semicircle formed in the second frame unit 120 roll in a manner of approaching each other. That is, T1 becomes shorter. At this time, the other end of the semicircle formed in the first frame unit 110 and the other end of the semicircle formed in the second frame unit 120 become farther from each other, and the other side of the cable becomes longer accordingly. That is, T2 becomes longer.

[0098] On the contrary, when the pulley rotates in the other direction, the other side of the cable becomes shorter, and the other side end of the semicircle formed in the first frame unit 110 and the other side end of the semicircle formed in the second frame unit 120 roll in a manner of approaching each other. That is, T2 becomes shorter. At this time, one side end of the semicircle formed in the first frame unit 110 and one side end of the semicircle formed in the second frame unit 120 become farther from each other, and one side of the cable becomes longer accordingly. That is, T1 becomes longer.

[0099] In this way, when two identical semicircles of radius r (2 / d) are in rolling contact and rotated by θ°, the sum of the lengths of T1 and T2 is constant at 2d as shown below.

[0100] d=2r, T1=2r-2rsinθ, T2=2r+2rsinθ

[0101] T1+T2=2d

[0102] This means that the previous Figure 4 The 1-DOF rolling joint can be moved using a cable.

[0103] If the control concept of the 1-DOF rolling joint using the cable is extended to a 2-DOF rolling joint structure, then Figure 7 shown.

[0104] like Figure 7 As shown, a 2-DOF rolling joint can use two cables to control the movement.

[0105] Specifically, the first cable unit 160 is wound around a first pulley (not shown) located at the lower side of the first frame unit 110 in the figure. If the first pulley rotates in one direction, one side of the first cable unit 160 becomes shorter and the other side becomes longer. On the contrary, if the first pulley rotates in the other direction, one side of the first cable unit 160 becomes longer and the other side becomes shorter. At this time, the length shortened by winding around the first pulley is the same as the length lengthened by unwinding from the first pulley.

[0106] Similarly, the second cable unit 170 is wound around the second pulley (not shown) located at the lower side of the first frame unit 110 in the figure. If the second pulley rotates in one direction, one side of the second cable unit 170 becomes shorter and the other side becomes longer. On the contrary, if the second pulley rotates in the other direction, one side of the second cable unit 170 becomes longer and the other side becomes shorter. At this time, the length shortened by winding around the second pulley is the same as the length lengthened by unwinding from the second pulley.

[0107] Next, one side of the first cable unit 160 is passed through a hemisphere (not shown in the figure, see Figure 5 One end of (a) 110 ') is fixed to a hemisphere with a radius of r (d / 2) formed in the second frame unit 120 (not shown in the figure, refer to Figure 5 At this time, the length of the first cable unit 160 connecting one end of the hemisphere 110' formed on the first frame unit 110 and one end of the hemisphere 120' formed on the second frame unit 120 is defined as Ta.

[0108] In addition, the other side of the first cable unit 160 passes through a hemisphere with a radius of r=d / 2 formed on the first frame unit 110 (not shown in the figure, refer to Figure 5 The other end of (a) 110 ') is fixed to a hemisphere with a radius of r = d / 2 formed in the second frame unit 120 (not shown in the figure, refer to Figure 5 At this time, the length of the first cable unit 160 connecting the other end of the hemisphere 110' formed on the first frame unit 110 and the other end of the hemisphere 120' formed on the second frame unit 120 is defined as Tb.

[0109] Ta and Tb are arranged on both sides with respect to the rotating shaft unit 130 .

[0110] Similarly, one side of the second cable unit 170 passes through a hemisphere (not shown in the figure, see Figure 5 One end of (a) 110 ') is fixed to a hemisphere with a radius of r = d / 2 formed in the second frame unit 120 (not shown in the figure, refer to Figure 5 At this time, the length of the second cable unit 170 connecting one end of the hemisphere 110' formed on the first frame unit 110 and one end of the hemisphere 120' formed on the second frame unit 120 is defined as Tc.

[0111] In addition, the other side of the second cable unit 170 passes through a hemisphere with a radius of r=d / 2 formed on the first frame unit 110 (not shown in the figure, refer to Figure 5 The other end of (a) 110 ') is fixed to a hemisphere with a radius of r = d / 2 formed in the second frame unit 120 (not shown in the figure, refer to Figure 5 At this time, the length of the second cable unit 170 connecting the other end of the hemisphere 110' formed on the first frame unit 110 and the other end of the hemisphere 120' formed on the second frame unit 120 is defined as Td.

[0112] Tc and Td are arranged on both sides with respect to the rotation axis unit 130. Tc is located at a position rotated 90 degrees with respect to Ta around the rotation axis, and Td is located at a position rotated 90 degrees with respect to Tc around the rotation axis.

[0113] According to the above configuration, by controlling the rotation of the first pulley and the second pulley, the lengths Ta and Tb of the first cable unit 160 and the lengths Tc and Td of the second cable unit 170 are adjusted, thereby achieving rolling motion of the second frame unit 120 relative to the first frame unit 110 .

[0114] By the principle as described above, during rolling motion, the sum of the lengths of Ta and Tb and the sum of the lengths of Tc and Td are respectively kept constant at 2d.

[0115] Ta+Tb=Tc+Td=2d

[0116] This means that the previous Figure 5 The 2-DOF rolling joint in (a) and (b) can use two cables to control the movement.

[0117] Figure 8 yes Figure 3 The exploded perspective view of the cam slider portion shown, Fig. 9 (a) to (e) show Figure 2 A conceptual diagram showing the structural changes of the cam slider portion caused by the tumbling rotation of the second frame unit 120.

[0118] Also refer to Figure 8 and the previous Figure 3 The first link unit 140 includes a first link 142 and first cams 141 respectively connected to both sides of the first link 142. The first cam 141 is rotatably disposed on the first frame unit 110 and the second frame unit 120 around the first axis. The first link 142 is rotatably disposed on the first cam 141 around the second axis, and can move relative to the first cam 141 by sliding.

[0119] Similarly, the second link unit 150 includes a second link 152 and second cams 151 respectively connected to both sides of the second link 152. The second cam 151 is rotatably provided on the first frame unit 110 and the second frame unit 120 around the second axis. The second link 152 is rotatably provided on the second cam 151 around the first axis, and can move relative to the second cam 151 by sliding.

[0120] The first link 142 and the first cam 141 , and the second link 152 and the second cam 151 include the cam slider portion as described above to correct the connection length between the first frame unit 110 and the second frame unit 120 when the second frame unit 120 rotates relative to the first frame unit 110 .

[0121] Specifically, the cam slider portion includes: a pin hole 151a and a cam groove 151b formed in the first cam 141 and the second cam 151, a hole 152a and a groove 152b formed in the first connecting rod 142 and the second connecting rod 152, a connecting rod sliding member 153 installed in the pin hole 151a and formed to be movable along the groove 152b, and a cam sliding member 154 installed in the hole 152a and formed to be movable along the cam groove 151b.

[0122] Among them, the pin hole 151a and the hole 152a are respectively used to fix the connecting rod slider 153 and the cam slider 154, and the cam groove 151b and the groove 152b are respectively equivalent to the hole 152a used to guide the movement of the cam slider 154 and the connecting rod slider 153.

[0123] The cam groove 151b and the groove 152b are extended and formed in a preset form. In this embodiment, the cam groove 151b is formed in a free curve form, and the groove 152b is formed in a straight line form. However, the present invention is not limited to this. The cam groove 151b and the groove 152b can be deformed into various forms as long as the second frame unit 120 can simulate rolling motion relative to the first frame unit 110.

[0124] According to the above structure, Fig. 9 As shown in (a) to (e), when the second frame unit 120 rolls relative to the first frame unit 110, the position of the first link 142 relative to the first cam 141 and the position of the second link 152 relative to the second cam 151 can be adjusted.

[0125] Fig.10 (a) to (d) show Figure 1 The diagram is a conceptual diagram showing the structural changes of the portion A of the hand 101 when the hand 101 yaws.

[0126] Also refer to Fig.10 (a) to (d) and the previous Figure 1 The rotating shaft unit 130 is centered on the central axis of each hollow part ( Figure 1 The first hollow part 110a and the second hollow part 120a are rotatably provided with a third axis (corresponding to the third axis) as the center. Therefore, in a state where the positions of the first frame unit 110 and the second frame unit 120 are fixed, the rotation axis unit 130 can rotate in place, that is, yaw rotation. Through the above-mentioned yaw rotation, the frame cover 122 of the second frame unit 120 and the hand 101 mounted thereon also yaw rotate together.

[0127] At this time, since the positions of the first frame unit 110 and the second frame unit 120 are fixed, the first cable unit 160 and the second cable unit 170 and the first link unit 140 and the second link unit 150 remain fixed without length changes.

[0128] In order to rotate the rotating shaft unit 130 in place, that is, to perform yaw rotation, a power transmission unit 190 is provided for transmitting power to the rotating shaft unit 130 using a cable. The power transmission unit 190 includes a first bevel pulley 191 , a second bevel pulley 192 , a cable 193 , and a power transmission shaft 194 .

[0129] The first conical pulley 191 is arranged so that its rotation axis is perpendicular to the extending direction of the power transmission shaft 194. In this figure, the first conical pulley 191 is arranged in parallel on the inner side of the forearm frame.

[0130] The second conical pulley 192 is arranged such that its rotation axis is perpendicular to the rotation axis of the first conical pulley 191 .

[0131] The cable 193 is wound around the first cone pulley 191 and the second cone pulley 192, so that the first cone pulley 191 and the second cone pulley 192 are interlocked with each other. That is, if the first cone pulley 191 rotates in one direction, the cable 193 is wound in one direction, and the second cone pulley 192 rotates clockwise. If the first cone pulley 191 rotates in the other direction, the cable 193 is wound in the other direction, and the second cone pulley 192 rotates counterclockwise.

[0132] For reference, although not shown in the present drawing, a driving pulley connected to a driving motor to rotate the first conical pulley 191 may be separately provided, and the driving pulley may be connected to the first conical pulley 191 via a cable 193, so that the first conical pulley 191 may rotate as the driving pulley rotates.

[0133] The power transmission shaft 194 is coupled to the second cone pulley 192 to rotate together with the second cone pulley 192 and coupled to the rotation shaft unit 130 to transmit rotational force to the rotation shaft unit 130. The power transmission shaft 194 may be coupled to the second joint 133 rotatably provided in the hollow portion of the first frame unit 110.

[0134] By arranging the first bevel pulley 191 and the second bevel pulley 192 perpendicularly to each other and interlocking them with the cable 193 , the rotational force can be transmitted to the rotating shaft unit 130 connected to the second bevel pulley 192 , thereby achieving yaw rotation of the joint device 100 .

[0135] On the other hand, in order to detect the rotation angle when the rotation axis unit 130 rotates in place, that is, yaws, a detection unit 103 may be provided. As an example, the detection unit 103 may detect the rotation angle of the rotation axis unit 130 by detecting the rotation of the second conical pulley 192. In this figure, the detection unit 103 is provided on the substrate 102 arranged on the second conical pulley 192 in an overlapping manner, and the rotation of the second conical pulley 192 is detected.

[0136] Fig.11 (a) to (h) show Figure 2 The diagram is a conceptual diagram showing the structural changes of the portion A when the second frame unit 120 performs rolling motion (rolling and / or pitching rotation) relative to a virtual spherical surface.

[0137] Also refer to Fig.11 (a)~(h) and the previous Figures 1 to 3 , Figure 8 and Fig. 9 (a) to (e), by adjusting the lengths of both sides of the first cable unit 160 and the second cable unit 170, the second frame unit 120 can form a rolling motion relative to the first frame unit 110 relative to the virtual spherical surface to perform roll and / or pitch rotation.

[0138] On the other hand, in addition to the detection unit 103 for detecting the rotation angle when the rotation axis unit 130 rotates in situ, that is, yaw rotation, as described above, a detection unit 104 for detecting the angle of the above-mentioned roll and / or pitch rotation may be provided. As described above, when the above-mentioned roll and / or pitch rotation occurs, the first cam 141 and the second cam 151 rotate relative to the first axis and the second axis. Taking advantage of this, the detection unit 104 may be provided on the first frame unit 110 and the first cam 141 and the second cam 151 to detect the rotation angle of the first link unit 140 and the second link unit 150 relative to the first axis and the second axis.

[0139] In this way, the rotation angle of the joint can be accurately measured by detecting the rotation angle of the first link unit 140 and the second link unit 150 relative to the first axis and the second axis and the rotation of the rotation axis unit 130 relative to the third axis by the detection units 103 and 104. When the joint device 100 of the present invention is set at the wrist joint part of the robot, the above detection technology can be applied to more accurately control the drive of the wrist.

[0140] Hereinafter, a structure that can solve the problems of sudden bending of the cable, resulting damage, error, etc. will be described.

[0141] Fig.12 yes Figure 1 A cross-sectional view of part A, Fig.13 It is shown in Fig.12 The illustrated state is a conceptual diagram of a state in which the second frame unit 120 is rolling (rolling and pitching) relative to a virtual spherical surface.

[0142] Also refer to Fig.12 and Fig.13 and the previous Figures 1 to 3 The first frame unit 110 includes a curved cable guide 180 for guiding the first cable unit 160 and the second cable unit 170. The cable guide 180 is provided in the hole 110b of the first frame unit 110 and includes an opening 180a through which the first cable unit or the second cable unit 160, 170 passes.

[0143] The cable guides 180 are provided at four locations of the first frame unit 110. A pair of cable guides 180 are provided on both sides of the rotation axis unit 130 for passing both sides of the first cable unit 160, and another pair of cable guides 180 are provided in a vertical direction for passing both sides of the second cable unit 170.

[0144] The cable guide 180 has arc portions 181 and 182 formed to bulge inward on the inner side of the opening 180a. The arc portions 181 and 182 are configured to guide the bending of the first cable unit 160 and the second cable unit 170 when the second frame unit 120 rolls (rolls and / or pitches) relative to the virtual spherical surface.

[0145] The arc portions 181 and 182 are arranged so that the points 180b that protrude most toward the inside of the opening 180a are spaced apart from the first and second rotation axes of the rotation axis unit 130 corresponding to the first and second axes in a direction away from the second frame unit 120. Fig.12 The most protruding point 180b is located below the connecting shaft 130a between the shaft portion 131 and the first joint 132 and the connecting shaft 130b between the first joint 132 and the second joint 133.

[0146] On the other hand, Fig.13 As shown, when the second frame unit 120 performs rolling motion (tumbling and pitching rotation) relative to the virtual spherical surface, one side of each cable unit is connected to the inner arc 181 adjacent to the rotating axis unit 130, and the other side is connected to the outer arc 182, and their contact ranges are different.

[0147] In consideration of this, the outer arc 182 may be formed to extend upwardly than the inner arc 181. That is, the outer arc 182 is formed to be higher to compensate for the above-mentioned contact range difference.

[0148] As such, by providing the cable guide 180 in the first frame unit 110, the bending of the cable can be smoothly guided, and considering the difference in contact range between the cable guide 180 and the cable, the inner arc 181 and the outer arc 182 have different designs, thereby minimizing the cable error caused by the above-mentioned bending.

[0149] Hereinafter, a wiring structure utilizing an empty space of the rotating shaft unit 130 will be described.

[0150] Fig.14 yes Figure 1 The cross-sectional view of the robot joint device 100 is shown.

[0151] Reference Fig.14 The cable 105 is configured to pass through the rotating shaft unit 130. For this purpose, the shaft portion 131 has a hollow shape with both ends open, and the first joint 132 and the second joint 133 each have a hollow portion. In addition, the power transmission shaft 194 connected to the rotating shaft unit 130 to transmit power also has a hollow shape.

[0152] Therefore, the cable 105 may be configured to pass through the inside of the power transmission shaft 194 and the inside of the rotation shaft unit 130. For reference, the cable 105 may be connected to the hand 101 to apply power or a signal to the hand 101.

[0153] In this way, the cable 105 is configured to pass through the inside of the shaft 131 and the first connector 132 and the second connector 133, thereby preventing the existing cable 105 from being configured in an external structure and causing problems such as twisting and stretching of the cable 105 due to the driving of the joint.

[0154] On the other hand, the above detailed description should not be interpreted as limiting in all aspects, but should be considered as illustrative. The scope of the present invention should be determined by a reasonable interpretation of the scope of the attached claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention.

Claims

1. A joint device for a robot, characterized in that: include: A first frame unit having a first hollow portion; A second frame unit, arranged to be separated from the first frame unit and having a second hollow portion; A rotating shaft unit is provided in each of the first hollow part and the second hollow part so as to be rotatable around a first axis, a second axis and a third axis perpendicular to each other; a first link unit extending so as to surround the rotating shaft unit, connected to the first frame unit and the second frame unit respectively via the rotating shaft unit, and arranged to be rotatable around the first axis and the second axis; and The second link unit extends around the rotating shaft unit in a state of crossing the first link unit, is connected to the first frame unit and the second frame unit respectively via the rotating shaft unit, and is arranged to be rotatable around the first shaft and the second shaft. The first connecting rod unit and the second connecting rod unit respectively have a cam slider portion, and the cam slider portion is configured to correct the connection length between the first frame unit and the second frame unit when rotating for the rolling motion in such a way that the second frame unit can perform a rolling motion relative to a virtual spherical surface relative to the first frame unit.

2. The robot joint device according to claim 1, characterized in that: One end of the first link unit connected to the first frame unit and one end of the second link unit connected to the first frame unit are arranged to be perpendicular to each other with the rotation axis unit as the center. The other end portion of the first link unit connected to the second frame unit and the other end portion of the second link unit connected to the second frame unit are arranged to be perpendicular to each other with the rotation axis unit as the center.

3. The robot joint device according to claim 1, characterized in that: The cam slider portion is provided at each of both ends of the first link unit and both ends of the second link unit.

4. The robot joint device according to claim 3, characterized in that: The first connecting rod unit comprises: a first cam provided on the first frame portion and the second frame portion so as to be rotatable about the first axis; and The first link is provided on the first cam so as to be rotatable about the second axis and is configured to be relatively movable with respect to the first cam by sliding movement. The second connecting rod unit comprises: a second cam provided on the first frame portion and the second frame portion so as to be rotatable about the second axis; and The second link is provided on the second cam so as to be rotatable about the first axis, and is configured to be relatively movable with respect to the second cam by sliding movement.

5. The robot joint device according to claim 4, characterized in that: The cam slider portion comprises: a pin hole and a cam groove formed in the first cam and the second cam; holes and slots formed in the first link and the second link; A link slider installed in the pin hole and formed to be movable along the groove; and A cam slider is mounted in the hole and is formed to be movable along the cam groove.

6. The robot joint device according to claim 4, characterized in that: A detection unit is further included. The detection unit is provided at the first frame unit, the first cam, and the second cam and is configured to detect a rotation angle of the first link unit and the second link unit relative to the first shaft and the second shaft.

7. The robot joint device according to claim 1, characterized in that: A driving unit is further included, the driving unit being configured to rotate the second frame unit relative to the first frame unit around the first axis and the second axis.

8. The robot joint device according to claim 7, characterized in that: The driving unit comprises: A first cable unit is wound around the first pulley and passes through the first frame unit on both sides, and both ends are rotatably provided in the second frame unit; and The second cable unit is wound around the second pulley and passes through the first frame unit on both sides, and both ends are rotatably arranged on the second frame unit. Between the first frame unit and the second frame unit, two sides of the first cable unit are located on a first plane, and two sides of the second cable unit are located on a second plane perpendicular to the first plane.

9. The robot joint device according to claim 8, characterized in that: The invention also includes a cable guide, which is disposed in the hole of the first frame unit and is formed with an opening for the first cable unit or the second cable unit to pass through. The inner side surface of the opening is provided with an arc portion formed to be convex toward the inner side so as to guide bending of the first cable unit and the second cable unit when the second frame unit rotates relative to the first frame unit.

10. The robot joint device according to claim 9, characterized in that: The arc portion comprises: an inner arc located adjacent to the rotation axis unit; and An outer arc extends upward further than the inner arc.

11. The robot joint device according to claim 9, characterized in that: The location of the arc portion that protrudes most toward the inside of the opening is arranged to be spaced in a direction farther away from the second frame unit than the first and second rotation axes of the rotation axis unit corresponding to the first and second axes.

12. The robot joint device according to claim 1, characterized in that: The rotating shaft unit comprises: A shaft portion having a hollow interior; A first joint having a hollow portion and being provided at both ends of the shaft portion so as to be rotatable about the first shaft; and The second joint includes a hollow portion, is connected to the first joint so as to be rotatable about the second axis, and is provided in the first hollow portion and the second hollow portion so as to be rotatable about the third axis.

13. The robot joint device according to claim 12, characterized in that: It also includes a power transmission unit configured to transmit power to the rotating shaft unit. The power transmission unit comprises: First cone pulley; a second conical pulley, arranged to be perpendicular to the first conical pulley; a cable wound around the first conical pulley and the second conical pulley, and the second conical pulley is rotated by the winding; and The power transmission shaft is configured to be coupled to the second cone pulley and transmit the rotational force to the rotation shaft unit.

14. A joint device for a robot, characterized in that: include: A first frame unit having a first hollow portion; A second frame unit, arranged to be separated from the first frame unit and having a second hollow portion; A rotating shaft unit is provided in each of the first hollow part and the second hollow part so as to be rotatable around a first axis, a second axis and a third axis perpendicular to each other; A first link unit extending in a manner of surrounding the rotating shaft unit, connected to the first frame unit and the second frame unit respectively via the rotating shaft unit, and arranged to be rotatable around the first axis and the second axis; A second link unit, extending in a manner of encircling the rotating shaft unit in a state of crossing the first link unit, connected to the first frame unit and the second frame unit respectively via the rotating shaft unit, and arranged to be rotatable around the first axis and the second axis; A first cable unit is wound around the first pulley and passes through the first frame unit on both sides, and both ends are rotatably provided in the second frame unit; and The second cable unit is wound around the second pulley and passes through the first frame unit on both sides, and both ends are rotatably arranged on the second frame unit. Between the first frame unit and the second frame unit, two sides of the first cable unit are located on a first plane, and two sides of the second cable unit are located on a second plane perpendicular to the first plane.

15. The robot joint device according to claim 14, characterized in that: The invention also includes a cable guide, which is disposed in the hole of the first frame unit and is formed with an opening for the first cable unit or the second cable unit to pass through. The inner side surface of the opening is provided with an arc portion formed to be convex toward the inner side so as to guide bending of the first cable unit and the second cable unit when the second frame unit rotates relative to the first frame unit.

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