Robot

Abstract

The present invention provides a drive mechanism and a robot, which can both suppress the enlargement of the fourth pulley and achieve a large reduction ratio. The drive mechanism includes: a first pulley that rotates around a first axis; a motor that causes the first pulley to rotate around the first axis; a second pulley that is disposed separately from the first pulley and rotates around a second axis parallel to the first axis; a first belt that is wound around the first and second pulleys and transmits the power of the motor from the first pulley to the second pulley; a third pulley that is arranged in a direction along the second axis with the second pulley and rotates around the second axis integrally with the second pulley; a fourth pulley that is disposed separately from the third pulley and rotates around a third axis parallel to the second axis; a second belt that is wound around the third and fourth pulleys and transmits the power of the motor from the third pulley to the fourth pulley; and a first bearing that is located between the second and third pulleys and supports the second and third pulleys.

Description

[0001] This application is a divisional application of the patent application with an application date of January 26, 2022, an application number of 202210096580.3, and an invention title of "Drive Mechanism and Robot". Technical Field

[0002] The present invention relates to a drive mechanism and a robot. Background Art

[0003] For example, Patent Document 1 describes a SCARA robot having a drive mechanism. The drive mechanism includes: a first pulley fixed to the rotation shaft of a linear motor; a ball screw fixed to a spline shaft; a second pulley fixed to the ball screw; and a belt wound around the first pulley and the second pulley. In such a SCARA robot, when the rotation shaft of the linear motor rotates, the rotational driving force of the first pulley is transmitted to the second pulley via the belt, and the spline shaft rotates.

[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-118978

[0005] However, in a drive mechanism configured in this way, when it is desired to significantly decelerate the rotational speed of the ball screw relative to the rotational speed of the rotation shaft of the linear motor, it is necessary to increase the pulley ratio between the first pulley and the second pulley. Therefore, there is a technical problem that the diameter of the second pulley becomes larger, and correspondingly, the front end portion of the SCARA robot becomes bulky. Summary of the Invention

[0006] The drive mechanism of the present invention includes: a first pulley that rotates around a first axis;

[0007] a motor that causes the first pulley to rotate around the first axis;

[0008] a second pulley that is separately arranged from the first pulley and rotates around a second axis parallel to the first axis;

[0009] a first belt that is wound around the first pulley and the second pulley and transmits the power of the motor from the first pulley to the second pulley;

[0010] a third pulley that is arranged in a row with the second pulley in a direction along the second axis and rotates integrally with the second pulley around the second axis;

[0011] a fourth pulley that is separately arranged from the third pulley and rotates around a third axis parallel to the second axis;

[0012] a second belt that is wound around the third pulley and the fourth pulley and transmits the power of the motor from the third pulley to the fourth pulley; and

[0013] The first bearing is located between the second pulley and the third pulley and supports the second pulley and the third pulley.

[0014] The robot of the present invention has the above-described drive mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a side view showing the overall configuration of the robot according to the first embodiment.

[0016] Figure 2 It shows Figure 1 a top view of the internal structure of the second arm of the robot.

[0017] Figure 3 It shows Figure 2 a cross-sectional view of the drive mechanism of the second arm.

[0018] Figure 4 It is a cross-sectional view showing the drive mechanism of the robot according to the second embodiment.

[0019] Figure 5 It is a cross-sectional view showing the drive mechanism of the robot according to the third embodiment.

[0020] Figure 6 It is a cross-sectional view showing the drive mechanism of the robot according to the fourth embodiment.

[0021] REFERENCE SIGNS LIST

[0022] 100: Robot; 110: Base; 120: Arm; 130: First Arm; 140: Second Arm; 141: Housing; 150: End Effector; 151: Spline Nut; 152: Ball Screw Nut; 153: Spline Shaft; 160: End Effector; 171: Joint Actuator; 172: Joint Actuator; 181: Drive Mechanism; 182: Drive Mechanism; 190: Robot Control Device; 2: Motor; 21: Output Shaft; 31: First Pulley; 32: Second Pulley; 33: Third Pulley; 34: Fourth Pulley; 41: First Belt; 42: Second Belt; 51: First Reducer; 52: Second Reducer; 61: First Bearing; 611: Inner Ring; 612: Outer Ring; 613: Ball; 62: Second Bearing; 621: Inner Ring; 622: Outer Ring; 623: Ball; 7: Shaft Portion; 8: Connecting Portion; 81: First Bearing Support Portion; 82: Second Bearing Support Portion; 83: Connecting Portion; 9: Brake; J1: First Rotation Axis; J2: Second Rotation Axis; J3: Third Rotation Axis; JJ1: First Axis; JJ2: Second Axis; JJ3: Third Axis. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] Next, the drive mechanism and the robot of the present invention will be described in detail based on the embodiments shown in the drawings.

[0024] In addition, for ease of explanation, the X-axis, Y-axis, and Z-axis, which are three mutually orthogonal axes, are illustrated in each figure. Further, hereinafter, the upper side of each figure, i.e., the arrow side of the Z-axis, is set as the upper side in the vertical direction, and the lower side of each figure, i.e., the side opposite to the arrow of the Z-axis, is set as the lower side in the vertical direction. It should be noted that the meaning of "parallel" in the specification of this application includes not only the case of being parallel but also a state slightly deviated from parallel. That is to say, its meaning also includes a state regarded as the same as parallel in technical common sense. Similarly, the meaning of "orthogonal" in the specification of this application includes not only the case of being orthogonal but also a state slightly deviated from orthogonal. That is to say, its meaning also includes a state regarded as the same as orthogonal in technical common sense.

[0025] First Embodiment

[0026] Figure 1 is a side view showing the overall configuration of the robot according to the first embodiment. Figure 2 shows Figure 1 a top view of the internal structure of the second arm of the Figure 3 shows Figure 2 a cross-sectional view of the drive mechanism of the second arm of the

[0027] Figure 1 The shown robot 100 is a SCARA robot and is used, for example, in various operations such as holding, conveying, assembling, and inspecting workpieces such as electronic components. However, the use of the robot 100 is not particularly limited.

[0028] The robot 100 has a base 110 fixed to the ground and an arm 120 connected to the base 110. In addition, the arm 120 has: a first arm 130, the base end of which is connected to the base 110, and the first arm 130 rotates relative to the base 110 about a first rotation axis J1 along the vertical direction; and a second arm 140, the base end of which is connected to the front end of the first arm 130, and the second arm 140 rotates relative to the first arm 130 about a second rotation axis J2 along the vertical direction. The first rotation axis J1 and the second rotation axis J2 are parallel.

[0029] In addition, an operation head 150 is provided at the front end of the second arm 140. The operation head 150 has: a spline nut 151 and a ball screw nut 152, which are coaxially arranged at the front end of the second arm 140; and a spline shaft 153, which is inserted through the spline nut 151 and the ball screw nut 152. The spline shaft 153 can rotate relative to the second arm 140 about a third rotation axis J3 along the vertical direction as its central axis, and can move up and down along the third rotation axis J3. The third rotation axis J3 is parallel to the first rotation axis J1 and the second rotation axis J2.

[0030] However, there is no particular limitation on the operation head 150. For example, it may be configured as follows: two shafts are provided, one of which rotates about the third rotation axis J3, and the other moves up and down in the axial direction parallel to the third rotation axis J3.

[0031] In addition, an end effector 160 is installed at the lower end of the spline shaft 153. The end effector 160 can be appropriately selected as an end effector that can be easily disassembled and assembled and is suitable for the target operation. Examples of the end effector 160 include a hand that holds a workpiece by clamping or adsorbing, and an operation tool that performs a prescribed process on the workpiece.

[0032] In addition, the robot 100 has: a joint actuator 171, which connects the base 110 and the first arm 130 and rotates the first arm 130 relative to the base 110 about the first rotation axis J1; and a joint actuator 172, which connects the first arm 130 and the second arm 140 and rotates the second arm 140 relative to the first arm 130 about the second rotation axis J2. In addition, the robot 100 has: a drive mechanism 181, which rotates the spline nut 151 to rotate the spline shaft 153 about the third rotation axis J3; and a drive mechanism 182, which rotates the ball screw nut 152 to move the spline shaft 153 up and down in the direction along the third rotation axis J3.

[0033] In addition, the robot 100 has a robot control device 190, which is arranged in the base 110 and controls the driving of the joint actuators 171, 172 and the drive mechanisms 181, 182 based on instructions from a main computer (not shown). The robot control device 190 independently controls the joint actuators 171, 172 and the drive mechanisms 181, 182 respectively, so that the robot 100 can perform the required operations. The robot control device 190 has, for example, a processor composed of a computer and processing information, a memory communicably connected to the processor, and an external interface. In addition, various programs executable by the processor are stored in the memory, and the processor can read and execute various programs stored in the memory and the like.

[0034] The overall configuration of the robot 100 has been briefly described above. Next, based on Figure 2 andFigure 3 A detailed description will be given of a drive mechanism 181 that rotates the spline nut 151 to cause the spline shaft 153 to rotate about a third rotation axis J3.

[0035] As Figure 2 and Figure 3 shown, the drive mechanism 181 has a motor 2 as a drive source. The motor 2 is fixed to the housing 141 of the second arm 140, and its output shaft 21 rotates about a first axis JJ1 along the vertical direction. The motor 2 is an AC servo motor. However, there is no particular limitation on the motor 2, and for example, a DC servo motor, a stepping motor, etc. may also be used.

[0036] In addition, the drive mechanism 181 has a first pulley 31 disposed on the output shaft 21 of the motor 2 and rotating integrally with the output shaft 21 about the first axis JJ1. The lower end of the output shaft 21 is a free end, and the first pulley 31 can be detached from the lower end side. It should be noted that in the present embodiment, the first pulley 31 is directly disposed on the output shaft 21, but it is not limited thereto, and for example, a power transmission mechanism such as a gear or a speed reducer may be interposed therebetween.

[0037] In addition, the drive mechanism 181 has a second pulley 32 disposed separately from the first pulley 31 and rotating about a second axis JJ2 parallel to the first axis JJ1. The second pulley 32 is disposed on the front end side of the second arm 140 with respect to the first pulley 31 and is located between the spline shaft 153 and the first pulley 31. In addition, the second pulley 32 and the first pulley 31 are arranged in the direction along the X-Y plane. However, the arrangement of the second pulley 32 is not particularly limited.

[0038] In addition, the drive mechanism 181 has a first belt 41 wound around the first pulley 31 and the second pulley 32 and connecting them. Thus, when the first pulley 31 rotates, its rotation is transmitted to the second pulley 32 via the first belt 41, and the second pulley 32 rotates following the first pulley 31. The outer diameter of the second pulley 32 is larger than the outer diameter of the first pulley 31. Thus, the first pulley 31, the first belt 41, and the second pulley 32 constitute a first speed reducer 51 that reduces the rotational speed of the output shaft 21 of the motor 2.

[0039] In addition, the drive mechanism 181 has a third pulley 33 arranged in the direction along the second axis JJ2 with the second pulley 32 and rotating about the second axis JJ2. The third pulley 33 rotates integrally with the second pulley 32. The outer diameter of the third pulley 33 is smaller than the outer diameter of the second pulley 32.

[0040] In addition, the drive mechanism 181 has a fourth pulley 34 that is separately arranged from the third pulley 33 and rotates about a third axis JJ3 parallel to the first axis JJ1 and the second axis JJ2. The fourth pulley 34 is arranged on the front end side of the second arm 140 with respect to the third pulley 33 and is arranged coaxially with the spline shaft 153. That is, the third axis JJ3 coincides with the third rotation axis J3. In addition, the spline nut 151 is inserted through and fixed to the fourth pulley 34, and they rotate integrally. In addition, the fourth pulley 34 and the third pulley 33 are arranged side by side in the direction along the X-Y plane. However, the arrangement of the fourth pulley 34 is not particularly limited.

[0041] In addition, the drive mechanism 181 has a second belt 42 that is wound around the third pulley 33 and the fourth pulley 34 and connects them. Thus, when the third pulley 33 rotates, its rotation is transmitted to the fourth pulley 34 via the second belt 42, and the fourth pulley 34 rotates following the third pulley 33. The outer diameter of the fourth pulley 34 is larger than the outer diameter of the third pulley 33. Thus, the third pulley 33, the second belt 42, and the fourth pulley 34 constitute a second speed reducer 52 that reduces the rotational speed of the output shaft 21 of the motor 2.

[0042] It should be noted that the configuration of the drive mechanism 181 is not limited to this. For example, an idler pulley that applies tension to the second belt 42 may also be provided.

[0043] In such a drive mechanism 181, the driving force of the motor 2 is transmitted to the spline nut 151 via the first speed reducer 51 and the second speed reducer 52. In this way, by interposing the first speed reducer 51 and the second speed reducer 52 between the motor 2 and the spline nut 151, the spline nut 151 can be rotated at a required rotational speed. In addition, the degree of freedom in arranging the motor 2 is increased, and it is also easy to design the second arm 140.

[0044] In particular, by arranging two speed reducers between the motor 2 and the spline nut 151, the outer diameter of the fourth pulley 34 can be suppressed to be smaller compared to the case of arranging one speed reducer. Thus, the hypertrophy and weight of the front end portion of the second arm 140 can be suppressed, and a robot 100 with excellent driving characteristics can be realized. For example, when it is desired to reduce the rotational speed of the fourth pulley 34 to 1 / 9 of the output shaft 21, in the configuration of the present embodiment, the pulley ratio of the first speed reducer 51 is set to 3, and the pulley ratio of the second speed reducer 52 is set to 3. Thus, the excessive enlargement of the diameter of the fourth pulley 34 can be suppressed. In contrast, in the case of only the second speed reducer 52, that is, when the first speed reducer 51 is omitted and the third pulley 33 is arranged on the output shaft 21, the pulley ratio of the second speed reducer 52 has to be set to 9, resulting in an excessive enlargement of the diameter of the fourth pulley 34.

[0045] In addition, the drive mechanism 181 has a first bearing 61 disposed between the second pulley 32 and the third pulley 33. Further, the drive mechanism 181 has a second bearing 62 located below the third pulley 33 and configured to sandwich the third pulley 33 between it and the first bearing 61. That is, on the second shaft JJ2, the second bearing 62, the third pulley 33, the first bearing 61, and the second pulley 32 are arranged and configured in this order from the lower side. The first bearing 61 and the second bearing 62 respectively support the second pulley 32 and the third pulley 33 so as to be rotatable about the second shaft JJ2. The second pulley 32 is cantilever-supported from below by the first bearing 61, and the third pulley 33 is supported at both ends from above and below by the first bearing 61 and the second bearing 62.

[0046] Here, the rotation speed of the output shaft 21 is reduced by the first speed reducer 51. Accordingly, a larger torque is applied to the second belt 42 than to the first belt 41. Therefore, in order to maintain durability, it is necessary to make the rigidity of the second belt 42 greater than that of the first belt 41. Accordingly, the tension of the second belt 42 also becomes larger. As a result, a larger radial load is applied to the third pulley 33 than to the second pulley 32. Thus, as in the present embodiment, by supporting the third pulley 33 at both ends by the first bearing 61 and the second bearing 62, the displacement of the third pulley 33 caused by the above-mentioned radial load can be more effectively suppressed. Therefore, the rotation of the third pulley 33 is stable. In addition, compared with the case where the third pulley 33 is cantilever-supported by one bearing, the first bearing 61 and the second bearing 62 can also be miniaturized. However, it is not limited thereto, and the second bearing 62 may be omitted.

[0047] It should be noted that there are no particular limitations on the first bearing 61 and the second bearing 62. In the present embodiment, deep groove ball bearings are used as the first bearing 61 and the second bearing 62. According to deep groove ball bearings, they can withstand radial loads, axial loads in two directions, or combined loads thereof, and can also cope with high-speed rotation. In addition, since they are widely used, cost reduction can also be achieved.

[0048] In addition, the first bearing 61 has an inner ring 611 and an outer ring 612 that are concentrically arranged and a plurality of balls 613 disposed between them. Similarly, the second bearing 62 has an inner ring 621 and an outer ring 622 that are concentrically arranged and a plurality of balls 623 disposed between them. Further, the outer rings 612 and 622 of the first bearing 61 and the second bearing 62 are respectively fixed to the housing 141 of the second arm 140, and the shaft portion 7 along the second shaft JJ2 is inserted and fixed to the inner rings 611 and 621. And the second pulley 32 and the third pulley 33 are fixed to the shaft portion 7. With such a configuration, the second pulley 32 and the third pulley 33 can rotate integrally about the second shaft JJ2.

[0049] It should be noted that the upper end of the shaft portion 7 is a free end. Therefore, as described below, the first belt 41 can be removed from the second pulley 32 without being obstructed by the shaft portion 7.

[0050] Next, the fixing of the first bearing 61 and the second bearing 62 to the second arm 140 will be described. The drive mechanism 181 has a connecting portion 8 that connects the outer rings 612 and 622 of the first bearing 61 and the second bearing 62 to each other. And the connecting portion 8 is fixed to the housing 141 of the second arm 140. Thus, the first bearing 61 and the second bearing 62 are jointly fixed to the housing 141 of the second arm 140. With such a configuration, the fixing of the first bearing 61 and the second bearing 62 to the second arm 140 becomes easy. However, the method of fixing the first bearing 61 and the second bearing 62 to the second arm 140 is not particularly limited.

[0051] The connecting portion 8 has: a first bearing support portion 81 that supports the outer ring 612 of the first bearing 61; a second bearing support portion 82 that supports the outer ring 622 of the second bearing 62 and is fixed to the housing 141 of the second arm 140; and a connecting portion 83 that connects the first bearing support portion 81 and the second bearing support portion 82. Among them, the second bearing support portion 82 is integrally formed with the connecting portion 83, and the connecting portion 83 is screwed to the first bearing support portion 81. However, the configuration of the connecting portion 8 is not limited to this. For example, the first bearing support portion 81, the second bearing support portion 82, and the connecting portion 83 may also be constituted by mutually different components.

[0052] In addition, the connecting portion 83 passes through the inside of the second belt 42 that is wound around the third pulley 33 and the fourth pulley 34 in a ring shape to connect the first bearing support portion 81 and the second bearing support portion 82. That is to say, the connecting portion 8 passes through the inside of the second belt 42 to connect the first bearing 61 and the second bearing 62.

[0053] Above, the configuration of the drive mechanism 181 has been described. According to the drive mechanism 181, the attachment and detachment of the first belt 41 can be easily performed during operations such as repair, maintenance, and inspection. Specifically, by removing the first pulley 31 from the output shaft 21, the first belt 41 is loosened, and the first belt 41 can be removed from the first pulley 31 and the second pulley 32. During installation, the reverse steps can be performed. After winding the first belt 41 around the first pulley 31 and the second pulley 32, it is only necessary to fix the first pulley 31 to the output shaft 21. In this way, according to the drive mechanism 181, the attachment and detachment of the first belt 41 can be performed only by attaching and detaching the first pulley 31. Therefore, the attachment and detachment of the first belt 41 become easy.

[0054] In addition, by removing the operation head 150 from the second arm 140 and releasing the fourth pulley 34, the second belt 42 is loosened, and the second belt 42 can be removed from the third pulley 33 and the fourth pulley 34. During installation, the reverse steps can be performed. After hanging the second belt 42 around the third pulley 33 and the fourth pulley 34, the operation head 150 can be inserted and fixed to the housing 141 of the second arm 140. In this way, according to the drive mechanism 181, the second belt 42 can be loaded and unloaded only by loading and unloading the operation head 150. Therefore, the loading and unloading of the second belt 42 becomes easy. In particular, in the present embodiment, the connecting portion 8 passes through the inside of the second belt 42 to connect the first bearing 61 and the second bearing 62. Therefore, the removal of the second belt 42 is not hindered by the connecting portion 8, and the second belt 42 can be smoothly removed.

[0055] In addition, for example, in the case of having a tension pulley that applies tension to the second belt 42, by loosening the tension pulley, the second belt 42 can be removed from the third pulley 33 and the fourth pulley 34 without removing the operation head 150.

[0056] Here, once the belt is loosened, it is necessary to apply tension again during reinstallation, and this operation is rather troublesome. Therefore, assuming a configuration in which the second belt 42 needs to be removed in order to remove the first belt 41, operations of reapplying tension to the first belt 41 and the second belt 42 respectively are required, consuming a great deal of time. The same applies to the case of a configuration in which the first belt 41 needs to be removed in order to remove the second belt 42. In contrast, in the drive mechanism 181, it is neither necessary to remove the second belt 42 in order to remove the first belt 41 nor to remove the first belt 41 in order to remove the second belt 42. Therefore, the trouble of the operation of reapplying tension during reinstallation of the belt is reduced.

[0057] The robot 100 has been described above. As described above, the drive mechanism 181 included in such a robot 100 has: a first pulley 31 that rotates around a first axis JJ1; a motor 2 that causes the first pulley 31 to rotate around the first axis JJ1; a second pulley 32 that is disposed separately from the first pulley 31 and rotates around a second axis JJ2 parallel to the first axis JJ1; a first belt 41 that is wound around the first pulley 31 and the second pulley 32 and transmits the power of the motor 2 from the first pulley 31 to the second pulley 32; a third pulley 33 that is arranged in a direction along the second axis JJ2 with the second pulley 32 and rotates around the second axis JJ2 integrally with the second pulley 32; a fourth pulley 34 that is disposed separately from the third pulley 33 and rotates around a third axis JJ3 parallel to the second axis JJ2; a second belt 42 that is wound around the third pulley 33 and the fourth pulley 34 and transmits the power of the motor 2 from the third pulley 33 to the fourth pulley 34; and a first bearing 61 that is located between the second pulley 32 and the third pulley 33 and supports the second pulley 32 and the third pulley 33. According to such a configuration, even when a large reduction ratio is desired, the outer diameter of the fourth pulley 34 can be suppressed to be small. Therefore, it is possible to suppress the thickening and weight increase of the front end portion of the second arm 140, and a robot 100 having excellent driving characteristics can be realized. In addition, it is not necessary to remove the second belt 42 in order to remove the first belt 41, nor is it necessary to remove the first belt 41 in order to remove the second belt 42. Therefore, the attachment and detachment of the first belt 41 become easy. In addition, the trouble of re-applying tension when re-installing the belt is reduced.

[0058] In addition, as described above, the drive mechanism 181 has a second bearing 62 that is arranged so as to sandwich the third pulley 33 between the first bearing 61 and supports the third pulley 33. Thus, the third pulley 33 is supported at both ends by the first bearing 61 and the second bearing 62. Therefore, it is possible to more effectively suppress the displacement of the third pulley 33 caused by the tension of the second belt 42, and the rotation of the third pulley 33 is stable. In addition, compared with the case where the third pulley 33 is cantilever-supported only by the first bearing 61, it is also possible to miniaturize the first bearing 61 and the second bearing 62.

[0059] In addition, as described above, the drive mechanism 181 has a connecting portion 8 that passes through the inside of the second belt 42 and connects the first bearing 61 and the second bearing 62. Thus, the attachment and detachment of the second belt 42 can be performed without being hindered by the connecting portion 8.

[0060] In addition, as described above, the robot 100 has the drive mechanism 181. Therefore, the robot 100 can enjoy the effects of the drive mechanism 181 and can exhibit high maintainability.

[0061] Second Embodiment

[0062] Figure 4 It is a cross-sectional view showing the drive mechanism of the robot according to the second embodiment.

[0063] In the robot 100 of the present embodiment, except for the configuration of the second bearing 62 and the structure of the connecting portion 8 being different, the rest is the same as the robot 100 of the above-described first embodiment. It should be noted that in the following description, regarding the present embodiment, the description will be centered on the differences from the above-described embodiment, and the description of the same matters will be omitted. In addition, in Figure 4 the same reference numerals are given to the components having the same structure as those in the above-described embodiment.

[0064] As Figure 4 shown, in the drive mechanism 181 of the present embodiment, the second bearing 62 is located above the second pulley 32 and is arranged so as to sandwich the second pulley 32 between the first bearing 61. Therefore, the second pulley 32 is supported at both ends from above and below by the first bearing 61 and the second bearing 62, and the third pulley 33 is cantilever-supported from above by the first bearing 61. With such a configuration, the second pulley 32 can be supported in a more stable posture, and the rotation of the second pulley 32 is stable. In addition, compared with the case where the second pulley 32 is cantilever-supported only by the first bearing 61, the first bearing 61 and the second bearing 62 can also be miniaturized.

[0065] In addition, the connecting portion 8 has: a first bearing support portion 81 that supports the outer ring 612 of the first bearing 61 and is fixed to the housing 141 of the second arm 140; a second bearing support portion 82 that supports the outer ring 622 of the second bearing 62; and a connecting portion 83 that connects the first bearing support portion 81 and the second bearing support portion 82. Among them, the first bearing support portion 81 is integrally formed with the connecting portion 83, and the connecting portion 83 and the second bearing support portion 82 are fixed by screwing. However, the structure of the connecting portion 8 is not limited to this.

[0066] In addition, the connecting portion 83 passes through the inside of the first belt 41 that is wound around the first pulley 31 and the second pulley 32 in a ring shape to connect the first bearing support portion 81 and the second bearing support portion 82. That is to say, the connecting portion 8 passes through the inside of the first belt 41 to connect the first bearing 61 and the second bearing 62. Thereby, the operation of removing the first pulley 31 from the output shaft 21 and removing the first belt 41 from the first pulley 31 and the second pulley 32 is not hindered by the connecting portion 8, and this operation can be carried out smoothly.

[0067] As described above, the drive mechanism 181 in the present embodiment has a second bearing 62. As described above, the second bearing 62 is arranged so that the second pulley 32 is sandwiched between the first bearing 61 and supports the second pulley 32. Thus, the second pulley 32 is supported at both ends by the first bearing 61 and the second bearing 62. Therefore, the rotation of the second pulley 32 is more stable. In addition, compared with the case where the second pulley 32 is cantilever-supported only by the first bearing 61, the first bearing 61 and the second bearing 62 can also be miniaturized.

[0068] In addition, as described above, the drive mechanism 181 has a connecting portion 8 that passes through the inside of the first belt 41 and connects the first bearing 61 and the second bearing 62. Thus, the attachment and detachment of the first belt 41 can be performed without being hindered by the connecting portion 8.

[0069] The same effects as those of the above-described first embodiment can also be achieved by the second embodiment.

[0070] Third Embodiment

[0071] Figure 5 It is a cross-sectional view showing the drive mechanism of the robot according to the third embodiment.

[0072] In the robot 100 of the present embodiment, in addition to the drive mechanism 181, it further has a brake 9, and the rest is the same as the robot 100 of the above-described first embodiment. It should be noted that in the following description, regarding the present embodiment, the description will be centered on the differences from the above-described embodiments, and the description of the same matters will be omitted. In addition, in Figure 5 the same reference numerals are given to the components that are the same as those in the above-described embodiments.

[0073] As Figure 5 shown, the drive mechanism 181 of the present embodiment has a brake 9 that restricts the rotation of each of the pulleys 31, 32, 33, and 34. The brake 9 is provided on the shaft portion 7 and restricts the rotation of each of the pulleys 31, 32, 33, and 34 by restricting the rotation of the shaft portion 7. The brake 9 is not particularly limited as long as it can be switched between a state of restricting the rotation of the shaft portion 7 and a state of allowing the rotation of the shaft portion 7.

[0074] In particular, the brake 9 is arranged below the second bearing 62. Thus, for example, compared with the case where the brake 9 is arranged above the second pulley 32, since there is no component between them, the brake 9 can be arranged near the bearing. Therefore, the rotation of the shaft portion 7 can be stably restricted by using the brake 9. In addition, by arranging the brake 9 below the second bearing 62, the attachment and detachment of the first belt 41 are hardly affected.

[0075] With such a third embodiment, the same effects as those of the above-described first embodiment can also be achieved.

[0076] Fourth Embodiment

[0077] Figure 6 FIG. is a cross-sectional view showing a drive mechanism included in a robot according to the fourth embodiment.

[0078] In the robot 100 of the present embodiment, except that the drive mechanism 181 further includes a brake 9, the rest is the same as the robot 100 of the above-described second embodiment. It should be noted that, in the following description, regarding the present embodiment, the description will focus on the differences from the above-described embodiments, and the description of the same matters will be omitted. In addition, in Figure 6 the same reference numerals are assigned to the components that are the same as those in the above-described embodiments.

[0079] As Figure 6 shown, the drive mechanism 181 of the present embodiment includes a brake 9 that restricts the rotation of each of the pulleys 31, 32, 33, and 34. The brake 9 is provided on the shaft portion 7, and restricts the rotation of each of the pulleys 31, 32, 33, and 34 by restricting the rotation of the shaft portion 7. The brake 9 is not particularly limited as long as it can switch between a state of restricting the rotation of the shaft portion 7 and a state of allowing the rotation of the shaft portion 7.

[0080] In particular, the brake 9 is disposed above the second bearing 62. Thus, for example, compared with the case where the brake 9 is disposed below the third pulley 33, since there are no components intervening between them, the brake 9 can be disposed near the bearing. Therefore, the rotation of the shaft portion 7 can be stably restricted by the brake 9. In addition, when viewed from above along the Z axis, the brake 9 is fixed to the housing 141 of the second arm 140 via the connecting portion 8 inside the first belt 41. Thus, the brake 9 hardly affects the attachment and detachment of the first belt 41.

[0081] With such a fourth embodiment, the same effects as those of the above-described first embodiment can also be achieved.

[0082] As described above, the drive mechanism and the robot of the present invention have been described based on the illustrated embodiments, but the present invention is not limited thereto, and the configuration of each part can be replaced with any configuration having the same function. In addition, any other components can be added to the present invention. In addition, the drive mechanism can also be applied to any device other than a robot.

Claims

1. A robot, characterized in that, it comprises: a base; a first arm, connected to the base and rotatable relative to the base about a first rotation axis; a second arm, connected to the first arm and rotatable relative to the first arm about a second rotation axis; and a shaft, provided on the second arm, rotatable relative to the second arm about a third rotation axis and movable up and down along the direction of the third rotation axis, wherein the second arm has: a motor; a first pulley, connected to the motor and rotatable about a first axis; a second pulley, separately arranged from the first pulley and rotatable about a second axis parallel to the first axis; a first belt, wound around the first pulley and the second pulley; a third pulley, arranged in a row with the second pulley along the direction of the second axis and rotatable about the second axis; a shaft portion, enabling the second pulley and the third pulley to integrally rotate about the second axis; a fourth pulley, separately arranged from the third pulley and rotatable about a third axis parallel to the second axis; a second belt, wound around the third pulley and the fourth pulley; a ball screw nut, through which the shaft is inserted, and the ball screw nut moves the shaft up and down along the direction of the third rotation axis; a spline nut, through which the shaft is inserted, and the spline nut is connected to the fourth pulley and rotates the shaft about the third rotation axis; a first bearing, located between the second pulley and the third pulley and in contact with the shaft portion; and a second bearing, in contact with the shaft portion, wherein the shaft has an end portion capable of detaching and attaching an end effector, the third pulley is located between the first bearing and the second bearing and is configured to be clamped between the first bearing and the second bearing, the second belt is located between the first bearing and the second bearing, when observing the second bearing in a direction orthogonal to the second axis, the second bearing does not coincide with the third pulley, the distance between the spline nut and the end portion of the shaft is shorter than the distance between the ball screw nut and the end portion of the shaft.

2. A robot, characterized in that, it comprises: a base; a first arm, connected to the base and rotatable relative to the base about a first rotation axis; a second arm, connected to the first arm and rotatable relative to the first arm about a second rotation axis; and a shaft, provided on the second arm, rotatable relative to the second arm about a third rotation axis and movable up and down along the direction of the third rotation axis, wherein the second arm has: a motor; a first pulley, connected to the motor and rotatable about a first axis; a second pulley, separately arranged from the first pulley and rotatable about a second axis parallel to the first axis; a first belt, wound around the first pulley and the second pulley; a third pulley, arranged in a row with the second pulley along the direction of the second axis and rotatable about the second axis; a fourth pulley, separately arranged from the third pulley and rotatable about a third axis parallel to the second axis; a second belt, wound around the third pulley and the fourth pulley; A ball screw nut, through which the shaft is inserted, and the ball screw nut raises and lowers the shaft along the direction of the third rotation axis; A spline nut, through which the shaft is inserted, and the spline nut is connected to the fourth pulley and rotates the shaft around the third rotation axis; A first bearing, located between the second pulley and the third pulley; and A second bearing, arranged and configured in the direction along the second shaft with the third pulley; The shaft has an end portion capable of detaching and attaching an end effector; The third pulley is located between the first bearing and the second bearing and is configured to be sandwiched between the first bearing and the second bearing; The second belt is located between the first bearing and the second bearing; When observing the second bearing in the direction orthogonal to the second shaft, the second bearing does not coincide with the third pulley; The distance between the spline nut and the end portion of the shaft is shorter than the distance between the ball screw nut and the end portion of the shaft.

3. The robot according to claim 1 or 2, characterized in that when observing the first bearing in the direction orthogonal to the second shaft, the first bearing does not coincide with the second pulley.

4. The robot according to claim 1 or 2, characterized in that the robot has: a first bearing support portion, fixed to the housing of the second arm and supporting the first bearing.

5. The robot according to claim 1 or 2, characterized in that the robot has: a second bearing support portion, fixed to the housing of the second arm and supporting the second bearing.

6. The robot according to claim 1 or 2, characterized in that the robot includes: a joint actuator, connecting the first arm and the second arm.

7. The robot according to claim 1 or 2, characterized in that the motor has a motor body and an output shaft, and when observing the motor body in the direction orthogonal to the first shaft, the motor body does not coincide with the first bearing.

8. The robot according to claim 1 or 2, characterized in that the motor has a motor body and an output shaft, and when observing the motor body in the direction orthogonal to the first shaft, the motor body does not coincide with the third pulley.

9. The robot according to claim 1 or 2, characterized in that the tension of the second belt is greater than the tension of the first belt.

10. The robot according to claim 1 or 2, characterized in that when observing the second arm in a top view along a straight line parallel to the second shaft, the first shaft departs from a straight line, which passes through the third shaft and extends along the length direction of the second arm, and the distance between this straight line and the second shaft is shorter than the distance between this straight line and the first shaft.

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