Joint device for robot

Abstract

Disclosed is a joint device for a robot, comprising: an upper arm unit provided with a first rotating pulley, a second rotating pulley, and a third rotating pulley arranged in this order in one direction; a forearm unit provided with a fixed pulley; a connection unit having a first pivot shaft connected to the upper arm unit through the third rotating pulley and a second pivot shaft connected to the forearm unit through the fixed pulley; a first cable unit wound around the first rotating pulley in a first direction, bent between the second rotating pulley and the third rotating pulley, and fixed to the fixed pulley; and a second cable unit which is wound around the first rotating pulley in a second direction opposite to the first direction, is bent between the second rotating pulley and the third rotating pulley, is disposed so as to be offset from the first cable unit, and is fixed to the fixed pulley, and the fixed pulley is in rolling contact with the third rotating pulley.

Description

Technical Field

[0001] The present invention relates to a joint device for a robot arm having a rolling contact joint mechanism. Background Art

[0002] Thanks to the rapid development of technology and the expansion of its application fields, robotics has become an essential technology in the fields of production, service, medical, detection, military, aerospace, etc. The purpose of existing robots is to perform simple and repetitive tasks at high speed and precision, but recently, robots of various types and levels have been developed, such as robots that can share activity space with humans and industrial robots that can achieve safe physical contact with humans.

[0003] Therefore, a robot technology that can detect external forces and is safe in contact and collision while meeting high strength, rigidity, precision, and operating speed is required. To this end, the technology to make the robot joints have a structure and performance similar to that of a human arm with high degrees of freedom has become a core research topic, and research results reflecting the results are also being published.

[0004] However, the robot joint structure developed so far has a problem that the structure becomes very complicated in order to have sufficient strength and rigidity while having a high degree of freedom and a movable range. If the structure is simplified, the performance will inevitably be reduced. Therefore, a method for solving the above problem is needed. Summary of the invention

[0005] The first object of the present invention is to provide a robot joint device that has a simple structure, can be lightweight, can improve the reduction ratio, and has high strength and rigidity even when the angle of the joint changes.

[0006] A second object of the present invention is to provide a joint device for a robot that can minimize the load applied to drive cables, electric cables, etc. passing through a joint portion.

[0007] In order to achieve the first object of the present invention, the robot joint device of the present invention includes: an upper arm unit, which includes a first rotating pulley, a second rotating pulley and a third rotating pulley arranged in sequence along one direction; a forearm unit, which includes a fixed pulley; a connecting unit, which includes a first pivot and a second pivot, the first pivot passes through the third rotating pulley and is connected to the upper arm unit, and the second pivot passes through the fixed pulley and is connected to the forearm unit; a first cable unit is wound around the first rotating pulley in a first direction, and is fixed to the fixed pulley after being bent between the second rotating pulley and the third rotating pulley; and a second cable unit is wound around the first rotating pulley in a second direction opposite to the first direction, and is fixed to the fixed pulley after being bent between the second rotating pulley and the third rotating pulley and arranged to be offset from the first cable unit, and the fixed pulley is formed to be in rolling contact with the third rotating pulley.

[0008] The diameter of the winding portion of the third rotating pulley is formed to be larger than the diameter of the winding portion of the first rotating pulley.

[0009] The winding portion of the third rotating pulley is formed to have the same diameter as the winding portion of the fixed pulley.

[0010] The first cable unit and the second cable unit may respectively include: a first cable having a first diameter, overlapping into two and wound around the first rotating pulley; a second cable having a second diameter larger than the first diameter, connected to the first cable, and partially wound around the second rotating pulley, the third rotating pulley and the fixed pulley in a single-line manner; and a fixing member, arranged at an end of the second cable and fastened to the fixed pulley.

[0011] The fixing member may be configured to adjust tension by adjusting a depth of insertion into the fixing pulley.

[0012] The robot joint device of the present invention may further include: a supporting frame, which supports the above-mentioned third rotating pulley so as to be rotatable, and has a circular portion corresponding to the outer periphery of the above-mentioned third rotating pulley; a first constraint cable unit, which is respectively fixed to the above-mentioned fixed pulley and the above-mentioned circular portion in a manner that the above-mentioned fixed pulley is in rolling contact with the above-mentioned third rotating pulley; and a second constraint cable unit, which is respectively fixed to the above-mentioned fixed pulley and the above-mentioned circular portion in a state of crossing with the above-mentioned first constraint cable unit in a manner that the above-mentioned fixed pulley is in rolling contact with the above-mentioned third rotating pulley.

[0013] The first restraining cable unit and the second restraining cable unit may each include: a restraining cable partially wound around the circular portion and the fixing pulley; and fixing members provided at both ends of the restraining cable and fastened to the circular portion and the fixing pulley, respectively.

[0014] Any one of the fixing members provided at both ends of the restraining cable may be configured to adjust tension by adjusting a depth of insertion into the circular portion or the fixing pulley.

[0015] In order to achieve the second object of the present invention, the upper arm unit further includes a fourth rotating pulley arranged opposite to the third rotating pulley across the supporting frame, and the forearm unit further includes a fifth rotating pulley and a sixth rotating pulley respectively arranged on both sides of the fixed pulley, and the third rotating pulley and the fifth rotating pulley arranged on the same plane are staggered with first driving cables for driving the wrist joint assembly, and the fourth rotating pulley and the sixth rotating pulley arranged on the same plane are staggered with second driving cables for driving the wrist joint assembly.

[0016] The upper arm unit may further include an upper arm frame rotatably arranged on the first pivot, and the forearm unit may further include a forearm frame rotatably arranged on the second pivot. In the connecting unit, in order to limit the relative rotation angle of the upper arm unit relative to the connecting unit and the relative rotation angle of the forearm unit relative to the connecting unit, a stopper may be provided which contacts the upper arm frame and the forearm frame at a preset angle.

[0017] In the connection unit, an opening corresponding to the stopper may be formed so that whether the upper arm frame and the forearm frame are in contact with the stopper can be visually confirmed when the forearm unit is extended at a maximum angle relative to the upper arm unit.

[0018] A first bracket may be provided on a side of the third rotating pulley opposite to the upper arm frame, a second bracket may be provided on a side of the fixed pulley opposite to the forearm frame, and cables may be staggeredly arranged at the winding parts of the first bracket and the winding parts of the second bracket.

[0019] In addition, the present invention discloses a joint device for a robot, comprising: an upper arm unit, provided with a rotating pulley; a forearm unit, provided with a fixed pulley; a connecting unit, provided with a first pivot and a second pivot, the first pivot passing through the rotating pulley and connected to the upper arm unit, the second pivot passing through the fixed pulley and connected to the forearm unit; a first cable unit, configured to cover a portion of the rotating pulley and the fixed pulley, and fixed to the fixed pulley; and a second cable unit, configured to cover another portion of the rotating pulley and the fixed pulley, and fixed to the fixed pulley, and when the forearm unit rotates relative to the upper arm unit, the fixed pulley rolls in contact with the rotating pulley.

[0020] The winding portion of the rotating pulley is formed to have the same diameter as the winding portion of the fixed pulley.

[0021] The robot joint device of the present invention may further include: a support frame, which supports the above-mentioned rotating pulley so as to be rotatable and has a circular portion corresponding to the outer periphery of the above-mentioned rotating pulley; a first constraint cable unit, which is respectively fixed to the above-mentioned fixed pulley and the above-mentioned circular portion in a manner that the above-mentioned fixed pulley is in rolling contact with the above-mentioned rotating pulley; and a second constraint cable unit, which is respectively fixed to the above-mentioned fixed pulley and the above-mentioned circular portion in a state of crossing the above-mentioned first constraint cable unit in a manner that the above-mentioned fixed pulley is in rolling contact with the above-mentioned rotating pulley.

[0022] The effects of the present invention obtained by the above-mentioned solution are as follows.

[0023] First, since the upper arm unit and the forearm unit are connected by a rolling joint driven by a cable, a thin and light joint device can be realized. In the above structure, the diameter of the winding portion of the third rotating pulley can be made larger than the diameter of the winding portion of the first rotating pulley to improve the reduction ratio. In addition, during the relative rotation of the forearm unit relative to the upper arm unit, since the lengths of the first cable unit and the second cable unit wound around the third rotating pulley and the fixed pulley remain constant, high strength and rigidity can be maintained even if the angle of the joint changes.

[0024] Second, the drive cables for driving the wrist are staggered and arranged at the two pulleys constituting the rolling joint, so that the length of the cables does not change during the relative rotation of the forearm unit with respect to the upper arm unit, thereby minimizing the load applied to the cables when the angle of the joint changes. The above structure can be similarly applied to the arrangement of cables electrically connected to electronic components. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 1 is a perspective view showing a robot joint device according to an embodiment of the present invention.

[0026] Figure 2 yes Figure 1 An exploded perspective view of a robot joint device shown in FIG.

[0027] Figure 3 It is shown Figure 2 4 is a diagram showing a state in which the first rotating pulley is wound with the first cable unit and the second cable unit.

[0028] Figure 4 It is shown Figure 3 FIG. 4 is a diagram of a first rotating pulley shown in FIG.

[0029] Figure 5 It is shown Figure 2 FIG. 4 is a diagram of a fixed pulley and a first cable unit and a second cable unit fixed thereto, and a first restraining cable unit and a second restraining cable unit.

[0030] Figure 6 yes Figure 5 FIG. 4 is a diagram of a first cable unit and a second cable unit shown in FIG.

[0031] Figure 7 yes Figure 5 FIG. 4 is a diagram showing part A viewed from another angle.

[0032] Figure 8 and Fig. 9 It is used to illustrate Figure 1 A conceptual diagram of the driving mechanism of a joint device for a robot shown in FIG.

[0033] Fig.10 (a) and (b) are conceptual diagrams for explaining that the lengths of the first cable unit and the second cable unit wound around the third rotating pulley and the fixed pulley are kept constant during the relative rotation of the forearm unit with respect to the upper arm unit.

[0034] Fig.11 is shown wound around Figure 1 Conceptual diagram of the various cables of the joint section shown in FIG.

[0035] Fig.12 (a), (b) and Fig.13 1 is a conceptual diagram showing the arrangement of cables during the relative rotation of the forearm unit with respect to the upper arm unit.

[0036] Fig.14 This is a conceptual diagram for explaining that the length of the cable does not change during the relative rotation of the forearm unit with respect to the upper arm unit. DETAILED DESCRIPTION

[0037] 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 considered to be likely to confuse the gist of the embodiments disclosed in this specification, its detailed description is omitted. In addition, the drawings are only for the purpose of easily understanding 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 idea and technical scope of the present invention.

[0038] 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.

[0039] 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.

[0040] An expression in the singular includes an expression in the plural unless the meaning is clearly different in the context.

[0041] 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 the existence or additional possibilities of one or more other features or numbers, steps, actions, constituent elements, parts or combinations thereof in advance.

[0042] Figure 1 1 is a perspective view showing a robot joint device 100 according to an embodiment of the present invention. Figure 2 yes Figure 1 Exploded perspective view of the robot joint device 100 shown in FIG.

[0043] Reference Figure 1 and Figure 2 The robot joint device 100 of the present invention can be applied to the arm part of a humanoid robot. The robot joint device 100 includes an upper arm unit 110 , a forearm unit 120 , a connection unit 130 , a first cable unit 140 and a second cable unit 150 .

[0044] The upper arm unit 110 and the forearm unit 120 are rotatably provided on the connection unit 130 and are configured to be relatively rotatable. The connection unit 130 is a structure corresponding to the elbow portion of the arm, and has two pivots, namely, a first pivot 131 connected to the upper arm unit 110 and a second pivot 132 connected to the forearm unit 120. The forearm unit 120 can be configured to be relatively rotatable between a state of being unfolded to approximately 180 degrees and a state of being bent to approximately 0 degrees relative to the upper arm unit 110.

[0045] The relative rotation is achieved by winding the first cable unit 140 and the second cable unit 150 , during which the rotation axis of the forearm unit 120 rolls with the rotation axis of the upper arm unit 110 . This will be described in detail later.

[0046] The upper arm unit 110 includes a first rotating pulley 111, a second rotating pulley 112, and a third rotating pulley 113 arranged in sequence along one direction. The first rotating pulley 111 is arranged near the shoulder, and the third rotating pulley 113 is arranged corresponding to the elbow, thereby forming a first pivot 131.

[0047] The first rotating pulley 111 is configured to receive a driving force from the driving motor 119 and to be rotatable in two directions.

[0048] The winding portion diameter of the third rotating pulley 113 is formed larger than the winding portion 111a of the first rotating pulley 111, and the ratio of the winding portion diameter of the third rotating pulley 113 to the winding portion 111a of the first rotating pulley 111 corresponds to the speed reduction ratio.

[0049] It is preferable that the diameter of the winding portion of the second rotating pulley 112 is formed to be larger than the diameter of the winding portion 111 a of the first rotating pulley 111 and smaller than the diameter of the winding portion of the third rotating pulley 113 .

[0050] The forearm unit 120 includes a fixed pulley 121. The fixed pulley 121 is disposed corresponding to the elbow portion of the arm to form a second pivot 132. The winding portion diameter of the fixed pulley 121 is formed to be the same as the winding portion diameter of the third rotating pulley 113.

[0051] The fixed pulley 121 is configured to roll in contact with the third rotating pulley 113 when the forearm unit 120 rotates relative to the upper arm unit 110. For reference, if the driving mechanism is considered, the fixed pulley 121 is preferably configured to be in point contact or line contact with the third rotating pulley 113, but considering damage and noise caused by friction during rolling contact, it is preferably configured to have a slight gap.

[0052] The connection unit 130 includes a first pivot 131 that passes through the third rotating pulley 113 and is connected to the upper arm unit 110, and a second pivot 132 that passes through the fixed pulley 121 and is connected to the forearm unit 120. In a conventional humanoid robot, the arm elbow joint includes one pivot, whereas the present invention is different in that the joint device 100 includes two pivots.

[0053] The first cable unit 140 is wound around the first rotating pulley 111 in a first direction, and is bent between the second rotating pulley 112 and the third rotating pulley 113 to change direction, and then fixed to the fixed pulley 121. At this time, the first cable unit 140 can be wound around the second rotating pulley 112, the third rotating pulley 113, and the fixed pulley 121 in a manner of less than one turn.

[0054] The second cable unit 150 is wound around the first rotating pulley 111 in a second direction opposite to the first direction, and is bent between the second rotating pulley 112 and the third rotating pulley 113 to be arranged in an X-shaped staggered manner with the first cable unit 140, and then fixed to the fixed pulley 121. At this time, the second cable unit 150 can be wound around the second rotating pulley 112, the third rotating pulley 113, and the fixed pulley 121 in a manner of less than one turn.

[0055] As the first rotating pulley 111 rotates in the first direction or the second direction, the lengths of the first cable unit 140 and the second cable unit 150 are adjusted. Through the length adjustment, the fixed pulley 121 rotates in a rolling contact manner relative to the third rotating pulley 113 in the second direction or the first direction.

[0056] Specifically, when the first rotating pulley 111 rotates in the first direction, the first cable unit 140 is unwound from the first rotating pulley 111, and the second cable unit 150 is wound around the first rotating pulley 111. Therefore, the fixed pulley 121 rolls in contact with the third rotating pulley 113 in the second direction, and the forearm unit 120 rotates in the direction of arm bending.

[0057] On the contrary, when the first rotating pulley 111 rotates in the second direction, the first cable unit 140 is wound around the first rotating pulley 111, and the second cable unit 150 is unwound from the first rotating pulley 111. As a result, the fixed pulley 121 rolls in contact with the third rotating pulley 113 in the first direction, and the forearm unit 120 rotates in the direction of arm expansion.

[0058] Figure 3 It is shown Figure 2 FIG. 1 shows a state in which the first rotating pulley 111 is wound with the first cable unit 140 and the second cable unit 150. Figure 4 It is shown Figure 3 FIG. 1 is a diagram of a first rotating pulley 111 shown in FIG. Figure 5 It is shown Figure 2 2 is a diagram showing a fixed pulley 121 and first and second cable units 140 and 150 fixed thereto, and first and second restraining cable units 160 and 170. Figure 6 yes Figure 5 FIG. 1 shows a diagram of a first cable unit 140 and a second cable unit 150, Figure 7 yes Figure 5 FIG. 4 is a diagram showing part A viewed from another angle.

[0059] Refer to the previous figure and Figures 3 to 7 In order to maximize the reduction ratio, the diameter of the winding portion 111a of the first rotating pulley 111 should be minimized. To this end, the thickness of the cables of the first cable unit 140 and the second cable unit 150 should be reduced, but if the thickness of the cables is reduced, the rigidity and strength will be weakened.

[0060] When two thin cables are used as a whole to solve the above-mentioned problem, the rigidity and strength are improved, but the cable driving device becomes complicated, and there is a problem that the cable driving device is damaged when the cables are entangled during driving.

[0061] In the present invention, for the first rotating pulley 111, two thin cables are wound to minimize the diameter of the winding portion 111a of the first rotating pulley 111, and for the second rotating pulley 112, the third rotating pulley 113 and the fixed pulley 121, a thick cable is used to improve the rigidity and strength, thereby simplifying the cable driving device.

[0062] Specifically, the first cable unit 140 and the second cable unit 150 include first cables 141, 151, second cables 142, 152, and fixing members 143, 153, respectively.

[0063] The first cables 141 and 151 have a first diameter and are wound around the first rotating pulley 111 in two overlapping ways. The first cable 141 of the first cable unit 140 is wound around the first rotating pulley 111 in a first direction, and the first cable 151 of the second cable unit 150 is wound around the first rotating pulley 111 in a second direction.

[0064] To this end, a spiral groove 111a' defining a position for winding the two overlapping first cables 141 and 151 may be formed in the winding portion 111a of the first rotating pulley 111. That is, the spiral groove 111a' is configured to allow the two overlapping first cables 141 and 151 to be wound together.

[0065] On both sides of the spiral groove 111a', there may be hangers 111a' on which the first cables 141 and 151 can be hung and fixed. In this figure, it is shown that the first cable 141 of the first cable unit 140 is hung and fixed on the hanger 111a' located on the outside and is wound along the spiral groove 111a' in a first direction, and the first cable 151 of the second cable unit 150 is hung and fixed on the hanger 111a' located on the inside and is wound along the spiral groove 111a' in a second direction. The first cable 141 of the first cable unit 140 and the first cable 151 of the second cable unit 150 are configured to become close to each other as they are wound around the first rotating pulley 111.

[0066] The second cables 142 and 152 have a second diameter larger than the first diameter, are connected to the first cables 141 and 151, and are wound in a single-line manner around the second rotating pulley 112, the third rotating pulley 113, and the fixed pulley 121. The first cables 141 and 151 and the second cables 142 and 152 having different diameters from each other can be connected through cable joints 144 and 154. In this figure, the cable joints 144 and 154 are configured to clamp both ends of the first cables 141 and 151 and one end of the second cables 142 and 152.

[0067] The fixing members 143 and 153 are provided at the other ends of the second cables 142 and 152 and fastened to the fixing pulley 121. The fixing member 143 for fixing the second cable 142 of the first cable unit 140 and the fixing member 153 for fixing the second cable 152 of the second cable unit 150 may be arranged adjacent to each other.

[0068] The fixing members 143 and 153 can be configured to adjust the tension by adjusting the depth of insertion into the fixing pulley 121. In this figure, the fixing members 143 and 153 are formed as headless bolts (set screws) with threads formed on the outer periphery and sockets 143a and 153a formed on the upper ends for inserting a wrench.

[0069] The fixed pulley 121 may be provided with a threaded groove 121a to which the fixing members 143 and 153 formed by headless bolts can be screwed, and a cable guide groove 121b extending from the threaded groove 121a and guiding a space for installing the other end of the second cables 142 and 152. The threaded groove 121a for fixing the second cable 142 of the first cable unit 140 and the threaded groove 121a for fixing the second cable 152 of the second cable unit 150 are arranged adjacent to each other, and the cable guide grooves 121b extend in directions away from each other.

[0070] The thread groove 121a may be formed extending toward the center of the fixed pulley 121. In order to reduce weight, the fixed pulley 121 may have a spoke wheel form, and the thread groove 121a may be formed extending along the length direction at any spoke portion.

[0071] On the other hand, in order to make the fixed pulley 121 and the third rotating pulley 113 rolling contact, the robot joint device 100 further includes a support frame 114 , a first restraint cable unit 160 , and a second restraint cable unit 170 .

[0072] The support frame 114 supports the third rotating pulley 113 to be rotatable, and has a circular portion 114a corresponding to the outer circumference of the third rotating pulley 113. That is, the radius of curvature of the circular portion 114a corresponds to the radius of the third rotating pulley 113. The circular portion 114a is arranged to overlap a portion of the fixed pulley 121 in a direction perpendicular to the first pivot 131 and the second pivot 132, so that the first restraining cable unit 160 and the second restraining cable unit 170 are fixed.

[0073] For reference, the supporting frame 114 may also be formed to rotatably support the second rotating pulley 112 in addition to the third rotating pulley 113 .

[0074] For reference, a portion of the winding portion of the third rotating pulley 113 is configured to overlap another portion of the fixed pulley 121 in a direction perpendicular to the first pivot 131 and the second pivot 132 , so that the first cable unit 140 and the second cable unit 150 are wound.

[0075] In order to make the fixed pulley 121 roll in contact with the third rotating pulley 113, the first restraining cable unit 160 is fixed to the fixed pulley 121 and the circular portion 114a, respectively, and the second restraining cable unit 170 is fixed to the fixed pulley 121 and the circular portion 114a, respectively, in a state of crossing the first restraining cable unit 160 in an X-shaped manner. Therefore, the fixed pulley 121 can roll in contact and rotate relative to the third rotating pulley 113 without slipping like the contact surface of a Jacob's ladder.

[0076] The first restraining cable unit 160 and the second restraining cable unit 170 include restraining cables 161 , 171 and fixing members 162 , 172 , respectively.

[0077] The restraining cables 161 and 171 are partially wound around the circular portion 114a and the fixed pulley 121. The restraining cables 161 of the first restraining cable unit 160 and the restraining cables 171 of the second restraining cable unit 170 are arranged to cross each other in an X shape.

[0078] The fixing members 162 and 172 are disposed at both ends of the restraining cables 161 and 171 and are respectively fastened to the circular portion 114a and the fixed pulley 121. Any of the fixing members 162 and 172 disposed at both ends of the restraining cables 161 and 171 can be configured so that the tension can be adjusted by adjusting the depth of insertion into the circular portion 114a or the fixed pulley 121.

[0079] Figure 8 and Fig. 9 It is used to illustrate Figure 1 A conceptual diagram of a driving mechanism of a robot joint device 100 is shown in FIG. Figure 8 This is the state where the forearm unit 120 is maximally extended relative to the upper arm unit 110. Fig. 9 This is a state in which the forearm unit 120 is bent to the maximum extent relative to the upper arm unit 110 .

[0080] When the forearm unit 120 is maximally deployed at an angle close to 180 degrees relative to the upper arm unit 110, the first restraining cable unit 160 is configured to cover 1 / 4 of the outer circumference of the fixed pulley 121. Thus, the rotation angle of the forearm unit 120 relative to the upper arm unit 110 can be limited so that the forearm unit 120 can be deployed close to 180 degrees but will not be deployed further.

[0081] When the forearm unit 120 is bent to the maximum at an angle close to 0 degrees relative to the upper arm unit 110, the second restraining cable unit 170 is configured to cover 1 / 4 of the outer circumference of the fixed pulley 121. Thus, the rotation angle of the forearm unit 120 relative to the upper arm unit 110 can be limited so that the forearm unit 120 can be bent to a degree close to 0 degrees but will not bend further.

[0082] On the other hand, the angle at which the upper arm unit 110 is expanded and bent relative to the forearm unit 120 may be physically limited.

[0083] First, a structure in which the angle at which the upper arm unit 110 is opened relative to the forearm unit 120 is physically restricted will be described.

[0084] Also refer to the previous Figure 1 and 2 The upper arm unit 110 further includes an upper arm frame 116 rotatably disposed on a first pivot 131, and the forearm unit 120 further includes a forearm frame 124 rotatably disposed on a second pivot 132. The upper arm frame 116 is formed to be rotatable relative to the connection unit 130 around the first pivot 131, and the forearm frame 124 is formed to be rotatable relative to the connection unit 130 around the second pivot 132.

[0085] The fixed pulley 121 is coupled to the forearm frame 124 via a shaft, and when the fixed pulley 121 rolls with the third rotating pulley 113, the forearm frame 124 rotates relative to the connecting unit 130 around the second pivot 132. Therefore, the forearm frame 124 rotates relative to the upper arm frame 116.

[0086] In addition, as the second pivot 132 moves due to the rolling contact of the fixed pulley 121 with respect to the third rotating pulley 113 , the connecting unit 130 also rotates relative to the upper arm frame 116 about the first pivot 131 .

[0087] Considering the above mechanism, the connection unit 130 is provided with a stopper 133 that contacts the upper arm frame 116 and the forearm frame 124 at a preset angle. In this embodiment, the protrusions 116a and 124a that are respectively engaged with the stopper 133 are formed to protrude from the ends of the upper arm frame 116 and the forearm frame 124 when the forearm unit 120 is maximally extended at an angle close to 180 degrees relative to the upper arm unit 110. That is, the stopper 133 is configured to limit the relative rotation angle of the upper arm unit 110 with respect to the connection unit 130 and the relative rotation angle of the forearm unit 120 with respect to the connection unit 130.

[0088] When the first rotating pulley 111 rotates at a preset number of rotations and the arm unit 120 is in a fully extended state relative to the upper arm unit 110, the first restraining cable unit 160 is configured to cover 1 / 4 of the outer circumference of the fixed pulley 121, and the protrusions 116a and 124a of the upper arm frame 116 and the forearm frame 124 are stopped by the stopper 133.

[0089] If the respective protrusions 116a, 124a of the upper arm frame 116 and the forearm frame 124 are not stopped by the stopper 133 even though the first rotating pulley 111 is rotated by a preset number of rotations for full extension of the forearm unit 120 relative to the upper arm unit 110, a problem may occur in which the forearm unit 120 is further rotated relative to the upper arm unit 110 due to an unexpected external force. This causes an unexpected load to be caused to at least one of the first rotating pulley 111 and the first restraining cable unit 160, and may cause damage in some cases.

[0090] In order to prevent such a problem, an opening 134 corresponding to the stopper 133 may be formed in the connection unit 130. When the forearm unit 120 is extended at the maximum angle relative to the upper arm unit 110, it can be visually confirmed through the opening 134 whether the protrusions 116a and 124a of the upper arm frame 116 and the forearm frame 124 are stopped by the stopper 133.

[0091] Similarly, the bending angle of the upper arm unit 110 relative to the forearm unit 120 may also be physically limited. For example, the forearm unit 120 may be configured to contact the upper arm unit 110 to limit further rotation when the forearm unit 120 is maximally bent relative to the upper arm unit 110 at an angle close to 0 degrees.

[0092] In this embodiment, the stopper 117 mounted on the support frame 114 is configured to contact the fixed pulley 121 when the forearm unit 120 is bent to the maximum at an angle close to 0 degrees relative to the upper arm unit 110. The stopper 117 and the fixed pulley 121 may be configured to be in surface contact, and for this purpose, the fixed pulley 121 may have a flat contact surface corresponding to the flat upper surface of the stopper 117.

[0093] By physically limiting the bending angle, the first cable unit 140 and the second cable unit 150 wound around the winding portion of the third rotating pulley 113 can be prevented from being separated.

[0094] Fig.10 (a) and (b) are conceptual diagrams for explaining that the lengths of the first cable unit 140 and the second cable unit 150 wound around the third rotating pulley 113 and the fixed pulley 121 remain constant during the relative rotation of the forearm unit 120 with respect to the upper arm unit 110.

[0095] Reference Fig.10 It can be confirmed from (a) and (b) that even if the forearm unit 120 is rotated 180 degrees relative to the upper arm unit 110 from the state of being unfolded 180 degrees and bent to face each other (0 degrees), the sum of the lengths of the first cable unit 140 and the second cable unit 150 wound around the third rotating pulley 113 and the fixed pulley 121 is constant. That is, the reduction ratio of the third rotating pulley 113 and the fixed pulley 121 in rolling contact is 1:1.

[0096] Therefore, the reduction ratio of the joint device 100 depends on the ratio of the diameter of the winding portion of the third rotating pulley 113 to the diameter of the winding portion 111a of the first rotating pulley 111. For example, when the diameter of the winding portion of the third rotating pulley 113 is three times the diameter of the winding portion 111a of the first rotating pulley 111, the reduction ratio is 1:3.

[0097] On the other hand, the present invention has a structure that can minimize the load applied to the drive cables 181 and 182 , the electric cable 183 , and the like passing through the joint.

[0098] Fig.11 is shown wound around Figure 1 A conceptual diagram of various cables 181, 182, and cables 183 of the joint portion shown in FIG. Fig.12(a) and (b) are conceptual diagrams for explaining that the lengths of the first driving cable 181 and the second driving cable 182 do not change during the relative rotation of the forearm unit 120 with respect to the upper arm unit 110 .

[0099] Also refer to Fig.11 and Fig.12 (a), (b) and the previous Figure 2 The upper arm unit 110 further includes a fourth rotating pulley 115 disposed opposite to the third rotating pulley 113 via a supporting frame 114 , and the forearm unit 120 further includes a fifth rotating pulley 122 and a sixth rotating pulley 123 disposed on both sides of the fixed pulley 121 .

[0100] The first driving cable 181 for driving the wrist joint assembly is arranged between the third rotating pulley 113 and the fifth rotating pulley 122 arranged on the same plane in a curved form between the third rotating pulley 113 and the fifth rotating pulley 122. Specifically, the first driving cable 181 is connected to a pulley (not shown) located on the upper arm unit 110 side, and one side and the other side of the first driving cable 181 are arranged between the third rotating pulley 113 and the fifth rotating pulley 122 so as to be staggered in an X shape.

[0101] Similarly, in the fourth rotating pulley 115 and the sixth rotating pulley 123 arranged on the same plane, the second driving cable 182 for driving the wrist joint assembly is arranged between the fourth rotating pulley 115 and the sixth rotating pulley 123 to be staggered in the shape of an X. Specifically, the second driving cable 182 is connected to a pulley (not shown) located on the upper arm unit 110 side, and one side and the other side of the second driving cable 182 are arranged between the fourth rotating pulley 115 and the sixth rotating pulley 123 to be staggered in the shape of an X.

[0102] Through the above configuration, the lengths of the first driving cable 181 and the second driving cable 182 do not change during the relative rotation of the forearm unit 120 relative to the upper arm unit 110. Therefore, the load applied to the first driving cable 181 and the second driving cable 182 when the angle of the joint changes can be minimized.

[0103] Fig.13 and Fig.14 1 is a conceptual diagram showing the arrangement of the cable 183 when the forearm unit 120 is rotating relative to the upper arm unit 110 .

[0104] Reference Fig.13 and Fig.14 A first bracket 118 is provided on a side of the third rotating pulley 113 opposite to the upper arm frame 116 , and a second bracket 125 is provided on a side of the fixed pulley 121 opposite to the forearm frame 124 .

[0105] The first bracket 118 has a winding portion at a portion facing the upper arm frame 116, and the second bracket 125 has a winding portion at a portion facing the forearm frame 124. Cables 183 are arranged at the winding portions of the first bracket 118 and the second bracket 125 with the winding portions staggered.

[0106] With the above configuration, the length of the cable 183 does not change during the relative rotation of the forearm unit 120 with respect to the upper arm unit 110. Therefore, it is possible to minimize the load applied to the cable 183 when the angle of the joint changes.

[0107] 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 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: The upper arm unit includes a first rotating pulley, a second rotating pulley, and a third rotating pulley arranged in sequence along one direction; A forearm unit with a fixed pulley; A connecting unit, comprising a first pivot and a second pivot, wherein the first pivot passes through the third rotating pulley and is connected to the upper arm unit, and the second pivot passes through the fixed pulley and is connected to the forearm unit; a first cable unit, which is wound around the first rotating pulley in a first direction, bent between the second rotating pulley and the third rotating pulley, and then fixed to the fixed pulley; and The second cable unit is wound around the first rotating pulley in a second direction opposite to the first direction, bent between the second rotating pulley and the third rotating pulley to be arranged to be offset from the first cable unit, and then fixed to the fixed pulley. The fixed pulley is in rolling contact with the third rotating pulley.

2. The robot joint device according to claim 1, characterized in that: The winding portion diameter of the third rotating pulley is larger than the winding portion diameter of the first rotating pulley.

3. The robot joint device according to claim 2, characterized in that: The winding portion diameter of the third rotating pulley is the same as the winding portion diameter of the fixed pulley.

4. The robot joint device according to claim 1, characterized in that: The first cable unit and the second cable unit respectively include: A first cable, having a first diameter, overlapped into two and wound around the first rotating pulley; a second cable having a second diameter larger than the first diameter, connected to the first cable, and partially wound around the second rotating pulley, the third rotating pulley, and the fixed pulley in a single-line manner; and A fixing member is provided at an end of the second cable and is fastened to the fixing pulley.

5. The robot joint device according to claim 4, characterized in that: The fixing member is configured to adjust tension by adjusting a depth of insertion into the fixing pulley.

6. The robot joint device according to claim 1, characterized in that: Also includes: a supporting frame that rotatably supports the third rotating pulley and has a circular portion corresponding to the outer circumference of the third rotating pulley; a first restraining cable unit fixed to the fixed pulley and the circular portion, respectively, in such a manner that the fixed pulley is in rolling contact with respect to the third rotating pulley; and The second restraint cable unit is fixed to the fixed pulley and the circular portion in a state of crossing the first restraint cable unit so that the fixed pulley is in rolling contact with the third rotating pulley.

7. The robot joint device according to claim 6, characterized in that: The first restraining cable unit and the second restraining cable unit respectively include: a restraining cable, a portion of which is wound around the circular portion and the fixed pulley; and The fixing members are arranged at both ends of the restraining cable and are respectively fastened to the circular portion and the fixing pulley.

8. The robot joint device according to claim 7, characterized in that: Any one of the fixing members provided at both ends of the restraining cable is configured to adjust tension by adjusting a depth of insertion into the circular portion or the fixing pulley.

9. The robot joint device according to claim 6, characterized in that: The upper arm unit further includes a fourth rotating pulley disposed opposite to the third rotating pulley across the support frame. The forearm unit further includes a fifth rotating pulley and a sixth rotating pulley respectively arranged on both sides of the fixed pulley. The first driving cable for driving the wrist joint assembly is staggeredly arranged on the third rotating pulley and the fifth rotating pulley arranged on the same plane. The second driving cables for driving the wrist joint assembly are staggeredly arranged on the fourth rotating pulley and the sixth rotating pulley arranged on the same plane.

10. The robot joint device according to claim 1, characterized in that: The upper arm unit further includes an upper arm frame rotatably disposed on the first pivot. The forearm unit further includes a forearm frame rotatably disposed on the second pivot. The connection unit includes a stopper that contacts the upper arm frame and the forearm frame at a predetermined angle in order to limit a relative rotation angle of the upper arm unit with respect to the connection unit and a relative rotation angle of the forearm unit with respect to the connection unit.

11. The robot joint device according to claim 10, characterized in that: The connection unit is formed with an opening corresponding to the stopper so that when the forearm unit is expanded at a maximum angle relative to the upper arm unit, whether the upper arm frame and the forearm frame are in contact with the stopper can be visually confirmed.

12. The robot joint device according to claim 10, characterized in that: A first bracket is provided on a side of the third rotating pulley opposite to the upper arm frame. A second bracket is provided on a side of the fixed pulley opposite to the forearm frame. The cables are arranged in a staggered manner at the winding portion of the first bracket and the winding portion of the second bracket.

13. A joint device for a robot, characterized in that: include: An upper arm unit having a rotating pulley; A forearm unit with a fixed pulley; A connecting unit, comprising a first pivot and a second pivot, wherein the first pivot passes through the rotating pulley and is connected to the upper arm unit, and the second pivot passes through the fixed pulley and is connected to the forearm unit; A first cable unit configured to cover the rotating pulley and a portion of the fixed pulley, and fixed to the fixed pulley; and A second cable unit is configured to cover the rotating pulley and another portion of the fixed pulley and is fixed to the fixed pulley, When the forearm unit rotates relative to the upper arm unit, the fixed pulley comes into rolling contact with the rotating pulley.

14. The robot joint device according to claim 13, characterized in that: The winding portion diameter of the rotating pulley is the same as the winding portion diameter of the fixed pulley.

15. The robot joint device according to claim 13, characterized in that: Also includes: a support frame that rotatably supports the rotating pulley and includes a circular portion that corresponds to the outer circumference of the rotating pulley; a first restraining cable unit fixed to the fixed pulley and the circular portion, respectively, in such a manner that the fixed pulley is in rolling contact with respect to the rotating pulley; and The second restraint cable unit is fixed to the fixed pulley and the circular portion in a state of crossing the first restraint cable unit so that the fixed pulley is in rolling contact with the rotating pulley.

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