Robot Hand Assembly

Abstract

To enhance work efficiency when mounting a plurality of arms of a robot hand so as to be symmetrical on the basis of an output shaft of a motor.SOLUTION: A robot hand assembly includes: a driving gear; three or more driven gears arranged at equal intervals along a circumferential direction of the driving gear, and engaged with the driving gear; and three or more arms 5 detachably mounted on rotary shafts of the three or more driven gears respectively, and extending in a direction orthogonal to the rotary shaft. Each arm includes: a mounting part 51 on which a gripping part for gripping an object to be gripped is detachably mounted; and contact parts 57, 58 formed so as to come into contact with other arms adjacent in the circumferential direction of the driving gear by forming an angle determined according to the total number of the arms.SELECTED DRAWING: Figure 4B

Description

[Technical field]

[0001] The present invention relates to a robotic hand assembly. [Background technology]

[0002] Patent Document 1 describes a robot hand in which a sun gear is fixed to the output shaft of a motor, planetary gears that mesh with this gear are arranged to surround the sun gear, and L-shaped, eccentric shaft, or spiral-shaped replaceable fingers can be attached to the rotation shaft of each planetary gear and removed freely. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-82140 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above conventional technology, the fingers (or arms) of the robot hand are appropriately selected according to the object to be grasped and are freely attached to the rotating shaft of the gear. However, it is considered to be quite difficult to attach multiple fingers (or arms) so that two adjacent fingers (or arms) in the circumferential direction of the motor output shaft are symmetrical with respect to the output shaft.

[0005] In view of the above-mentioned conventional technology, the present invention aims to improve work efficiency when attaching multiple arms of a robot hand so that two adjacent arms circumferentially adjacent to each other in the output shaft direction of a motor are symmetrical with respect to the output shaft. [Means for solving the problem]

[0006] A robot hand assembly according to the present invention includes a drive gear, three or more driven gears that are equally spaced around the circumferential direction of the drive gear and mesh with the drive gear, and three or more arms that are detachably attached to rotation shafts of the three or more driven gears and extend in a direction perpendicular to the rotation shafts. Each arm includes an attachment portion to which a gripping portion that grips an object to be gripped is detachably attached, and an abutment portion formed to abut against another arm adjacent to the circumferential direction of the drive gear at an angle determined according to the total number of the arms. The arm has a step along the direction of the rotation axis, and the abutment portion is provided on the step portion of the arm. Effect of the Invention

[0007] According to the present invention, the efficiency of work is improved when attaching a plurality of arms of a robot hand such that two arms adjacent in the circumferential direction of the output shaft of a motor are symmetrical with respect to the output shaft. [Brief description of the drawings]

[0008] [Figure 1A] FIG. 2 is a top view of the robot hand assembly according to the first embodiment. [Figure 1B] FIG. 1B is a partial cross-sectional view taken along line AA in FIG. 1A. [Diagram 2] FIG. 4 is a perspective view showing the arrangement of gears in a transmission mechanism. [Figure 3A] FIG. 2 is an exploded perspective view showing a transmission mechanism and an arm. [Figure 3B] FIG. [Figure 4A] FIG. [Figure 4B] FIG. [Figure 5A] 11 is a perspective view showing a state in which two circumferentially adjacent arms are rotated counterclockwise and come into contact with each other. FIG. [Figure 5B] FIG. 2 is a perspective view showing a standby state of the robot hand assembly. [Figure 6] 13 is a top view showing a state in which two circumferentially adjacent arms are rotated counterclockwise and come into contact with each other. FIG. [Figure 7]13 is a top view showing a state in which two circumferentially adjacent arms are rotated clockwise and come into contact with each other. FIG. [Figure 8A] 13 is a top view showing a state in which two circumferentially adjacent arms are rotated counterclockwise and brought into contact with each other in the second embodiment. FIG. [Figure 8B] 13 is a perspective view showing a state in which two circumferentially adjacent arms are rotated counterclockwise and brought into contact with each other in the second embodiment. FIG. [Figure 8C] FIG. 11 is a top view showing the arm according to the second embodiment. [Figure 9A] FIG. 13 is a top view showing a state in which two circumferentially adjacent arms are rotated counterclockwise and brought into contact with each other in the third embodiment. [Figure 9B] 13 is a perspective view showing a state in which two circumferentially adjacent arms are rotated counterclockwise and brought into contact with each other in the third embodiment. FIG. [Figure 9C] FIG. 13 is a top view showing a standby state in the third embodiment. [Figure 10A] FIG. 11 is a perspective view of an arm in a third embodiment. [Figure 10B] FIG. 11 is a top view of the arm in the third embodiment. [Figure 11] 13 is a perspective view showing a state in which two circumferentially adjacent arms are rotated clockwise and brought into contact with each other in the third embodiment. FIG. [Figure 12A] FIG. 13 is a top view showing a state in which two circumferentially adjacent arms are rotated counterclockwise and brought into contact with each other in the fourth embodiment. [Figure 12B] 13 is a perspective view showing a state in which two circumferentially adjacent arms are rotated counterclockwise and brought into contact with each other in the fourth embodiment. FIG. [Figure 12C] FIG. 13 is a top view showing a standby state in the fourth embodiment. [Figure 13A] FIG. 13 is a perspective view of an arm in a fourth embodiment. [Figure 13B] FIG. 13 is a top view of the arm in the fourth embodiment. [Figure 14A] FIG. [Figure 14B]FIG. 4 is a perspective view showing a rear surface of the transmission mechanism. [Figure 14C] FIG. 2 is a perspective view of a robot hand assembly. [Figure 15] FIG. [Figure 16A] 11A to 11C are explanatory diagrams showing a positioning process using an arm positioning jig. [Figure 16B] 11A to 11C are explanatory diagrams showing a positioning process using an arm positioning jig. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The following describes embodiments of the present invention, but the present invention is not limited to the following embodiments.

[0010] First Embodiment 1A and 1B, a robot hand assembly 1 includes a motor 2, a transmission mechanism 4 attached to the output shaft side of the motor for transmitting the rotation of an output shaft 2a of the motor, and an arm 5 driven by the rotation transmitted by the transmission mechanism. Arrow B1 indicates the output shaft direction, and arrow B2 indicates the opposite output shaft direction. A sensor 3 for detecting the rotation of the motor is attached to the opposite output shaft side of the motor 2 as needed.

[0011] As shown in Fig. 2, the transmission mechanism 4 includes a pinion 4a formed on the output shaft 2a of the motor 2, and three driven gears 4b1-4b3 that mesh with the pinion and rotate with the rotation of the pinion. In a top view of the robot hand assembly 1 (i.e., when the robot hand assembly 1 is viewed along the counter-output shaft direction B2), the three driven gears 4b1-4b3 are arranged at equal intervals in order in a clockwise direction around the output shaft 2a. The three driven gears 4b1-4b3 have the same dimensions and the same number of teeth, and each have a rotating shaft 4c1-4c3 that is parallel to the output shaft 2a. The three rotating shafts 4c1-4c3 are positioned at equal intervals along the circumferential direction of the output shaft 2a.

[0012] When there is no need to distinguish between the rotating shafts 4c1 to 4c3, they are simply called "rotating shaft 4c." The same applies to parts and portions thereof provided corresponding to each driven gear, such as driven gears 4b1 to 4b3 and arms 5a to 5c described later.

[0013] As shown in Figures 3A and 3B, thin arms 5a to 5c extending in a direction perpendicular to the rotation shafts 4c1 to 4c3 are detachably attached to the rotation shafts 4c1 to 4c3, respectively. A hole 52 extending in the same direction as the rotation shaft 4c is formed in the base end of the arm 5. A tapped hole (female thread) 56 extending in the longitudinal direction of the arm 5 and communicating with the hole 52 is formed in the end face on the base end side of both longitudinal end faces of the arm 5.

[0014] With respect to the arm 5, the longitudinal dimension is called the length, the dimension along the output shaft 2a is called the height, and the dimension perpendicular to both the longitudinal direction and the direction of the output shaft 2a is called the width.

[0015] The rotating shaft 4c has a tip portion 4d that is inserted into and fits into the hole portion 52 of the arm 5, a base portion 4e that has an outer diameter larger than that of the tip portion 4d, and a tapped hole 4f that is provided in the tip portion 4d, extends in the same direction as the rotating shaft 4c, and into which a first fixing screw 53 is fastened.

[0016] The tip 4d of the rotating shaft 4c is inserted into the hole 52 of the arm 5 while fitting it thereto, and then the first fixing screw 53 is fastened to the tapped hole 4f so as to press the bottom surface 55 of the arm 5 against the axial end surface of the base 4e of the rotating shaft 4c, thereby fixing the arm 5 in the removal direction. Furthermore, the second fixing screw 54 is fastened to the tapped hole 56 of the arm 5, thereby fixing the arm 5 in the idling direction of the rotating shaft 4c. In this way, the arm 5 and the rotating shaft 4c of the driven gear 4b are fixed to each other by the fixing screws, so that the arm 5 can be easily attached and detached.

[0017] A hole 51 extending in the same direction as the rotation axis 4c is formed at the tip of the arm 5. A gripping part (not shown) selected according to the shape of a workpiece (not shown) to be gripped is detachably attached to the arm 5 using this hole 51.

[0018] The operation of the robot hand assembly 1 is as follows. First, when the drive motor 2 rotates, the output shaft 2a and the pinion 4a rotate, and the rotational force is transmitted to the three driven gears 4b1 to 4b3. Then, the three rotating shafts 4c rotate synchronously, and the three arms 5 and grippers (not shown) rotate around the respective rotating shafts. The rotation of the grippers grips the workpiece, or releases the workpiece from the gripped state by the grippers.

[0019] Although an example has been shown in which the pinion 4a is directly cut onto the output shaft 2a of the drive motor 2, the present invention is not limited to this. A pinion, which is a separate part from the output shaft 2a, may be coupled to the output shaft 2a by press-fitting or the like.

[0020] The arms 5a to 5c are preferably fixed to the rotation shafts 4c1 to 4c3, respectively, so that two arms adjacent to each other in the circumferential direction of the pinion 4a are symmetrical with respect to the pinion 4a. By fixing in this manner, as shown in FIG. 1A, when all the arms are simultaneously opened (i.e., when the direction from the base end to the tip end of each arm is the radially outward direction of the pinion 4a), the tips of the arms are positioned at equal intervals along the circumferential direction of the pinion 4a. The state shown in FIG. 1A is called the standby state of the robot hand assembly 1. Details of fixing the arm 5 to the rotation shaft 4c will be described below.

[0021] 4A and 4B, the tip of arm 5 where hole 51 is provided is tapered such that the dimension in the width direction tapers off. Specifically, the tip of arm 5 has a tapered shape that is line-symmetrical with respect to the longitudinal axis of arm 5 when viewed from above. An angle α1 between tapered surface 57 of the tip of arm 5 and side surface 58 perpendicular to the width direction of arm 5 is 60 degrees.

[0022] Hereinafter, the tapered surfaces 57 of the arms 5a to 5c will be referred to as tapered surfaces 57a to 57c, respectively, as necessary. The same applies to the other portions of the arms 5a to 5c.

[0023] When fixing the arms 5, first, as shown in Fig. 5A and Fig. 6, the corresponding rotation shafts 4c are inserted into the holes 52 of the three arms 5, and the arms 5 are not fixed to the rotation shafts 4c. In this state, the arms 5 are rotated in the counterclockwise direction (in the direction of the arrow CCW) based on each rotation shaft. Then, the arms 5a, 5b, and 5c are brought into contact with each other near the center of the transmission mechanism 4. More specifically, the side surface 58a of the arm 5a is brought into contact with the tapered surface 57b of the arm 5b, the side surface 58b of the arm 5b is brought into contact with the tapered surface 57c of the arm 5c, and the side surface 58c of the arm 5c is brought into contact with the tapered surface 57a of the arm 5a.

[0024] In this state, the three arms 5a, 5b, and 5c are fixed to the rotation shafts 4c1, 4c2, and 4c3, so that the relative angles of the three arms 5a, 5b, and 5c can be accurately adjusted. The relative angle here refers to the angle between the longitudinal axes of the arms. In this way, the arms are arranged and fixed to the rotation shafts so that two arms adjacent to each other in the circumferential direction of the pinion 4a are symmetrical with respect to the pinion 4a. Then, as shown in FIG. 5B, when the three arms 5a, 5b, and 5c are opened, the tips of the arms are positioned at 120-degree intervals in the circumferential direction, and the distances between the tips of the arms and the corresponding rotation shafts are all equal.

[0025] Alternatively, as shown in FIG. 7, the direction of rotation may be clockwise (indicated by arrow CW) rather than counterclockwise, and the three arms 5a, 5b, and 5c may be fixed after being brought into contact with each other.

[0026] <Second embodiment> This embodiment is a modification of the first embodiment. In this embodiment, four driven gears are provided, and four arms are provided correspondingly. As shown in Figures 8A to 8C, an angle β1 between a tip surface 67 perpendicular to the longitudinal axis of the arm 6 and a side surface 68 perpendicular to the width direction of the arm 6 is 90 degrees. The four arms 6 are rotated in a counterclockwise direction (CCW direction) while inserted into the corresponding rotating shafts 4c, so that two arms adjacent to each other in the circumferential direction of the pinion 4a come into contact with each other (FIGS. 8A and 8B). Specifically, the side surface 68 of one arm comes into contact with the tip surface 67 of the other arm in the two arms adjacent to each other in the circumferential direction of the pinion 4a. By fixing the four arms 6 to the rotating shaft 4c in this state, the relative angles of the four arms 6 can be accurately adjusted. In other words, the four arms are arranged so that two arms adjacent to each other in the circumferential direction of the pinion 4a are symmetrical with respect to the pinion 4a, and when the four arms 6 are opened, the tips are positioned at 90-degree intervals in the circumferential direction of the pinion 4a.

[0027] <Third embodiment> The maximum size of the workpiece that can be grasped depends on the length of the arm. If the workpiece is relatively large, the arm needs to be long. On the other hand, depending on the length of the arm, when the arm is rotated and brought into contact, the two arms may not be able to abut near the center of the transmission mechanism.

[0028] 9A to 9C, 10A and 10B, the arm is lengthened and a step is provided in the height direction of the arm (i.e., the direction along the rotation axis 4c). The arm 7 has a lower step 7m and an upper step 7n extending in the arm longitudinal direction, and a step portion 7n1 extending in the arm height direction and connecting the lower step 7m and the upper step 7n. The lower step 7m is located on the base end side of the arm 7, and the upper step 7n is located on the tip end side of the arm 7.

[0029] The lower step 7m is provided with a hole 72 that fits with the rotating shaft 4c, and the upper step 7n is provided with a gripper attachment portion 71. The end of the step 7n1 on the base end side in the arm longitudinal direction is tapered so that the dimension in the width direction tapers toward the base end of the arm. The angle α2 between the tapered surface 77 of the step 7n1 and the side surface 78 of the upper step 7n perpendicular to the width direction of the arm 7 is 60 degrees.

[0030] The three arms 7 having such stepped portions are rotated counterclockwise while inserted into the rotating shaft 4c. Then, in two arms 7 adjacent to each other in the circumferential direction of the pinion 4a, the tapered surface 77 of one arm 7 and the side surface 78 of the other arm 7 are brought into contact with each other near the center of the transmission mechanism 4 (FIGS. 9A and 9B). In this state, by fixing each arm 7 to the corresponding rotating shaft 4c, the relative angles of the three arms 7 can be accurately adjusted. In other words, the three arms 7 are fixed in a state in which the two arms adjacent to each other in the circumferential direction of the pinion 4a are symmetrical with respect to the pinion 4a. When the arms 7 are opened, the tips of the arms 7 are positioned at 120-degree intervals in the circumferential direction of the pinion 4a as shown in FIG. 9C.

[0031] As shown in FIG. 11, the rotation direction may be set to the clockwise direction (CW direction), and the three arms 7 may be brought into contact with each other and then fixed to the rotating shaft.

[0032] <Fourth embodiment> This embodiment is a modified form of the third embodiment. In this embodiment, four relatively long arms are provided. As shown in Figs. 12A to 12C, 13A and 13B, the arm 8 includes a lower stage portion 8m, an upper stage portion 8n, and a step portion 8n1 connecting the lower stage portion 8m and the upper stage portion 8n. At the end of the step portion 8n1 on the base end side in the arm longitudinal direction, an angle β2 formed between an end face 87 on the base end side in the arm longitudinal direction and a side face 88 perpendicular to the width direction of the arm 8 is 90 degrees. Each arm is rotated, and in two arms adjacent in the circumferential direction of the pinion 4a, an end face 87 of one arm and a side face 88 of the other arm are brought into contact near the center of the transmission mechanism unit 4 (Figs. 12A and 12B). In this state, the four arms 8 are fixed to the rotation shaft 4c, so that the relative angles of the four arms 8 can be accurately adjusted. In other words, the four arms 8 can be fixed such that two arms adjacent to each other in the circumferential direction of the pinion 4a are symmetrical with respect to the pinion 4a.

[0033] <Other> 14A to 14C, the arm can be attached in a similar manner even when the transmission mechanism 4 or the drive motor 2 is replaced in the robot hand assembly 1. The drive motor 2 and the transmission mechanism 4 can be separated by removing the bolts 22 (FIG. 14C) that fasten the drive motor 2 and the transmission mechanism 4 together.

[0034] In addition, by removing the arm fixing screw that fixes the arm to the rotating shaft, it is possible to remove the arm from the transmission mechanism unit 4. After that, it is possible to replace each part and reassemble the arm. Specifically, the drive motor 2 and the transmission mechanism 4 are aligned at their respective fittings 21 and 41, and assembled with the fixing bolt 22. Next, the tip 4d of the rotating shaft is inserted into the hole 52 of the arm 5, and the two circumferentially adjacent arms are brought into contact with each other, and the relative angles of the arms are adjusted. After that, the arm is fixed to the rotating shaft with the arm fixing screw. When the sensor 3 is attached, it is possible to set the origin of the arm by setting the origin of the drive motor 2 in the state where the arm is in contact as shown in FIG. 5A.

[0035] <Other ways to fix the arm> As shown in Figures 15, 16A and 16B, when arranging three arms so that two adjacent arms in the circumferential direction of the pinion are symmetrical with respect to the pinion, it is also possible to use a dedicated arm positioning jig 9 without devising the arm shape as described above. A groove 91 in which the three arms are symmetrically housed is formed on the axial end face of the arm positioning jig 9, which is substantially triangular prism-shaped. By using such a jig and fitting the arms into the groove 91, the arms can be fixed symmetrically. However, using a jig is not good in terms of workability.

[0036] Alternatively, it is conceivable that the fingers could be shaped so that the tips of the gripping portions of the fingers butt together when closed, as shown in FIG. 5 of Patent Document 1, and the fingers could be fixed symmetrically in the butted state. However, the tips of the gripping parts of the fingers may be shaped to match the workpiece to be gripped, and it is not always possible to make the tips of the gripping parts of the fingers shaped to butt against each other when closed. In addition, in some cases, cushioning material is attached to the tips of the gripping parts of the fingers to prevent the workpiece from being scratched, etc. Even if the tips of the gripping parts of the fingers are shaped so that they fit together when closed, accurate positioning is difficult due to the flexure of the cushioning material. Furthermore, even if the tips of the gripping parts of the fingers themselves can be shaped so that they butt when closed, they will gradually wear out because they are the parts that grip the workpiece. Therefore, when a robot hand has been used for a certain period of time and the fixation between the fingers and the rotating shaft becomes misaligned and the fingers need to be readjusted, when a motor is replaced and the gears are able to rotate freely and the fingers are fixed at equal intervals again, or when only one of multiple fingers is replaced, it becomes difficult to accurately position the arm even if the gripping part tips butt against each other because the gripping part tips of each finger are worn out even when the fingers are closed.

[0037] According to the above first to fourth embodiments, the shape of the arms is designed so that when the arms engage with the respective rotating shafts and rotate in one direction in the pinion circumferential direction while not fixed, and any two arms adjacent to each other in the pinion circumferential direction are brought into contact with each other, the two arms are positioned symmetrically with respect to the pinion. When any two arms adjacent to each other in the pinion circumferential direction are brought into contact with each other, the relative angle between the two arms is 120 degrees when the total number of arms is three, and is 90 degrees when the total number of arms is four. In this way, the positioning and fixing of the arms can be easily performed. Since the shape of the arms themselves, which do not directly contact the workpiece to be gripped, is used to adjust the relative angle, the relative angle of the arms can be adjusted and fixed with the same accuracy regardless of the degree of wear of the gripping part attached to the arms when used.

[0038] As described above, according to the embodiment of the present invention, the following effects can be obtained. -An arm is provided separately from the gripping part that comes into direct contact with the workpiece to be gripped, and the arm can be positioned according to its shape. In this case, it is not affected by wear of the gripping part. The relative angle of the arm can be adjusted without using a special tool. Since there is no need to adjust the relative angle using the gripping part, the gripping part can be shaped freely to suit the workpiece. -Even if the arm is relatively long, the relative angle can be adjusted. When replacing the motor, the arm becomes free, but the relative angle of the arm can be easily adjusted after replacing the motor.

[0039] Regarding the embodiments described above, the following supplementary notes are disclosed. [Appendix 1] A drive gear; Three or more driven gears that are equally spaced along the circumferential direction of the drive gear and mesh with the drive gear; Three or more arms are detachably attached to the rotation shafts of the three or more driven gears, respectively, and extend in a direction perpendicular to the rotation shafts; Equipped with Each arm is A mounting portion to which a gripping portion for gripping an object to be gripped is detachably attached; a contact portion formed to contact another arm adjacent to the driving gear in the circumferential direction at an angle determined according to the total number of the arms; Equipped with Robot hand assembly. [Appendix 2] 2. The robot hand assembly of claim 1, wherein the abutment portion is provided at a tip portion of the arm. [Appendix 3] 2. The robot hand assembly of claim 1, wherein the arm has a step along the direction of the rotation axis, and the abutment portion is provided on the step portion of the arm.

[0040] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications and changes can be made based on the technical concept of the present invention. [Explanation of symbols]

[0041] 1 Robot hand assembly 2 Motors 2a Output shaft 3 Sensors 4 Transmission mechanism 4a Pinion 4b Driven gear 4c Rotation axis 5~8 Arms 57 Tapered surface 58 Side 67 Tip surface 68 Side 7m, 8m lower section 7n, 8n upper section 7n1, 8n1 Step 77 Tapered Surface 78 Side 87 End face 88 Side

Claims

[Claim 1] A drive gear; Three or more driven gears that are equally spaced along the circumferential direction of the drive gear and mesh with the drive gear; Three or more arms are detachably attached to the rotation shafts of the three or more driven gears, respectively, and extend in a direction perpendicular to the rotation shafts; Equipped with Each arm is A mounting portion to which a gripping portion for gripping an object to be gripped is detachably attached; a contact portion formed to contact another arm adjacent to the driving gear in the circumferential direction at an angle determined according to the total number of the arms; Equipped with The arm has a step along the direction of the rotation axis, and the abutment portion is provided on the step portion of the arm. Robot hand assembly.

Images