Planetary roller screw for robot arm

Abstract

The utility model relates to a planetary roller lead screw for a robot arm, which comprises a nut sleeve on the outer side, a lead screw shaft is inserted in the nut sleeve, the lead screw shaft comprises a lead screw head, a shaft rod and a connector, two ends of the lead screw head are respectively pivoted with annular retainers, a plurality of planetary lead screw rollers are inserted between the retainers, and the planetary lead screw rollers are connected with the connector. The planetary lead screw rollers are annularly and evenly distributed around the central axis of the lead screw head, and threads on the planetary lead screw rollers are in threaded connection with threads on the inner wall of the nut sleeve and threads on the outer wall of the lead screw head respectively. The lead screw shaft in the planetary roller lead screw is of a split structure, when the lead screw shaft needs to be replaced, only components in the lead screw shaft need to be replaced, manufacturing cost or replacement and maintenance cost can be saved, and the utilization rate of resources is increased.

Description

Technical field:

[0001] The utility model relates to the technical field of robot bearings, and more specifically to a planetary roller screw for a robot arm. Background technology:

[0002] As the process of industrialization in my country is getting faster and faster, the application of industrial robots in industry is becoming more and more popular. The main component of industrial robots, bearings, is becoming more and more widely valued. At present, the bearings on the robot arm are roller screw type structures, which include nuts (also called nut sleeves), screw shafts, rollers and cages. The outer wall of the roller and the outer wall of one end of the screw shaft are both formed with threads, and the roller is equivalent to the role of a ball, so that the screw shaft is screwed to the nut. However, the existing screw shaft is an integrated structure. According to the actual operation requirements of the robot, the size structure of its nut and roller is inconvenient, but the length and shaft diameter of the screw shaft have multiple specifications; so when the robot needs to adjust the distance from the arm to the object or the screw shaft has problems such as deformation and damage, the entire screw shaft needs to be replaced, so some people propose to design a split structure for the screw shaft, and when replacing it, only part of the split structure can be replaced, which can save costs. Therefore, it is necessary to design a screw shaft structure with a corresponding split structure but ensuring effective strength. Utility model content:

[0003] The purpose of the utility model is to address the deficiencies of the prior art and to provide a planetary roller screw for a robot arm. The screw shaft in the planetary roller screw adopts a split structure. When the screw shaft needs to be replaced, only the components therein need to be replaced, which can save manufacturing costs or replacement and maintenance costs and improve resource utilization.

[0004] A planetary roller screw for a robot arm comprises an outer nut sleeve, a screw shaft is inserted in the nut sleeve, the screw shaft comprises a screw head, a shaft and a connector, an annular retaining frame is pivotally connected to both ends of the screw head, a plurality of planetary screw rollers are inserted and connected between the retaining frames, the planetary screw rollers are evenly distributed in an annular shape around the central axis of the screw head, and the threads on the planetary screw rollers are respectively screwed with the threads on the inner wall of the nut sleeve and the threads on the outer wall of the screw head;

[0005] A cylindrical connecting seat is formed at one end of the screw head, a D-shaped socket is formed on the end surface of the connecting seat, a center hole is formed on the bottom surface of the D-shaped socket and passes through the end surface of the other end of the screw head, and a concave platform connected to the center hole is formed on the end surface of the other end of the screw head;

[0006] The end of the shaft rod close to the screw head is formed with a D-shaped limit plug, the limit plug is inserted into the D-shaped socket of the screw head and is formed with a center axis, the center axis passes through the center hole of the screw head and is clamped with a clamp ring, and the clamp ring is inserted into the concave platform of the screw head;

[0007] A bottom threaded hole is formed on the end surface of the shaft rod away from the screw head, a stud is formed on the connecting head, the stud is screwed into the bottom threaded hole of the shaft rod, and the connecting head is pressed against the end surface of the shaft rod.

[0008] Preferably, a countersunk hole is formed on the shaft rod at the entrance of the bottom threaded hole, a spring washer is inserted into the countersunk hole, and the two end faces of the spring washer are pressed against the shaft rod and the connecting head respectively; the spring washer is inserted into the stud of the connecting head, and a pin hole is formed on the connecting head.

[0009] Preferably, the central axis of the screw shaft coincides with the central axis of the nut sleeve, two sets of central gear rings are formed on the screw head of the screw shaft, planetary gear rings are formed on the outer walls of both ends of the planetary screw rollers, and the planetary gear rings of the planetary screw rollers are respectively meshed with the central gear rings on the screw head;

[0010] The two ends of the planetary screw roller are formed with support shafts, and the support shafts are respectively inserted into the retaining frames.

[0011] A plurality of slots are formed on the outer wall of the screw head, and the retaining frame is inserted into the slot of the screw head. The end surface of one end of the retaining frame abuts against the side wall of the slot, and the other end abuts against a retaining spring, which is clamped in the slot of the screw head.

[0012] Preferably, the diameter of the outer wall of the connecting seat on the screw head is larger than the diameter of the outer wall of the screw head and smaller than the diameter of the inner wall of the nut sleeve; the diameter of the outer wall of the shaft is not larger than the diameter of the outer wall of the connecting seat and not smaller than the diameter of the outer wall of the limit plug.

[0013] Preferably, limiting grooves are formed on the outer walls on both sides opposite to each other of the shaft rod.

[0014] The beneficial effects of the utility model are:

[0015] The screw shaft in the planetary roller screw adopts a split structure. When the screw shaft needs to be replaced, only the parts therein need to be replaced, which can save manufacturing costs or replacement and maintenance costs and improve resource utilization. Description of the drawings:

[0016] Figure 1 It is a three-dimensional structural schematic diagram of the utility model;

[0017] Figure 2 It is a schematic diagram of the structure of the utility model in partial section;

[0018] Figure 3 for Figure 2 A local enlarged schematic diagram of the middle A;

[0019] Figure 4 for Figure 2 A local enlarged schematic diagram of point B in the middle.

[0020] In the figure: 1. nut sleeve; 2. screw head; 21. connecting seat; 22. D-type socket; 23. center hole; 24. recess; 3. planetary screw roller; 31. support shaft; 4. shaft; 41. limit groove; 42. limit plug; 43. center shaft; 44. annular groove; 45. bottom threaded hole; 46. countersunk hole; 5. crossbeam plate; 6. connector; 61. pin hole; 62. stud; 7. retaining ring; 8. spring washer; 9. retaining spring. Specific implementation method:

[0021] Example: See Figures 1 to 4 As shown, a planetary roller screw for a robot arm comprises an outer nut sleeve 1, a screw shaft is inserted in the nut sleeve 1, the screw shaft comprises a screw head 2, a shaft rod 4 and a connector 6, an annular retaining frame 5 is pivotally connected to both ends of the screw head 2, a plurality of planetary screw rollers 3 are inserted and connected between the retaining frames 5, the planetary screw rollers 3 are evenly distributed in an annular shape around the central axis of the screw head 2, and the threads on the planetary screw rollers 3 are respectively screwed with the threads on the inner wall of the nut sleeve 1 and the threads on the outer wall of the screw head 2;

[0022] A cylindrical connection seat 21 is formed at one end of the screw head 2, a D-shaped socket 22 is formed on the end surface of the end of the connection seat 21, a center hole 23 penetrating the end surface of the other end of the screw head 2 is formed on the bottom surface of the D-shaped socket 22, and a concave platform 24 connected to the center hole 23 is formed on the end surface of the other end of the screw head 2;

[0023] The end of the shaft 4 close to the screw head 2 is formed with a D-shaped limit plug 42, the limit plug 42 is inserted into the D-shaped socket 22 of the screw head 2 and is formed with a center axis 43, the center axis 43 passes through the center hole 23 of the screw head 2 and is clamped with a snap ring 7, and the snap ring 7 is inserted into the concave platform 24 of the screw head 2; an annular groove 44 is formed on the outer wall of the end of the screw head 2, the snap ring 7 is inserted into the annular groove 44 and abuts against the bottom surface of the concave platform 24;

[0024] A bottom threaded hole 45 is formed on the end surface of the shaft rod 4 away from the screw head 2 , and a stud 62 is formed on the connecting head 6 . The stud 62 is screwed into the bottom threaded hole 45 of the shaft rod 4 , and the connecting head 6 is pressed against the end surface of the shaft rod 4 .

[0025] A countersunk hole 46 is formed on the shaft rod 4 at the entrance of the bottom threaded hole 45, and a spring washer 8 is inserted into the countersunk hole 46. The two end faces of the spring washer 8 are pressed against the shaft rod 4 and the connecting head 6 respectively; the spring washer 8 is inserted into the stud 62 of the connecting head 6, and a pin hole 61 is formed on the connecting head 6. The spring washer 8 can limit the looseness between the connecting head 6 and the shaft rod 4.

[0026] The central axis of the screw shaft coincides with the central axis of the nut sleeve 1, two sets of central gear rings are formed on the screw head 2 of the screw shaft, and planetary gear rings are formed on the outer walls of both ends of the planetary screw roller 3, and the planetary gear rings of the planetary screw roller 3 are respectively meshed with the central gear rings on the screw head 2;

[0027] The two ends of the planetary screw roller 3 are formed with support shafts 31 , and the support shafts 31 are respectively inserted into the retaining frame 5 .

[0028] A plurality of slots are formed on the outer wall of the screw head 2, and the retaining frame 5 is inserted into the slots of the screw head 2. The end face of one end of the retaining frame 5 abuts against the side wall of the slot, and the other end abuts against a retaining spring 9, which is clamped in the slot of the screw head 2.

[0029] The diameter of the outer wall of the connecting seat 21 on the screw head 2 is larger than the diameter of the outer wall of the screw head 2 and smaller than the diameter of the inner wall of the nut sleeve 1; the diameter of the outer wall of the shaft 4 is not larger than the diameter of the outer wall of the connecting seat 21 and not smaller than the diameter of the outer wall of the limit plug 42.

[0030] The shaft rod 4 has two opposite outer walls formed with limiting grooves 41 .

[0031] Working principle: The utility model is a planetary roller screw for a robot arm, and its technology is embodied in the screw shaft. The screw shaft is composed of a screw head 2, a shaft rod 4 and a connector 6. The screw head 2, the shaft rod 4 and the connector 6 can be combined and connected, wherein the shaft rod 4 adopts a limit plug 42 to achieve radial limit with the screw head 2, and at the same time, the central shaft 43 can effectively improve the connection strength between the shaft rod 4 and the screw head 2, thereby ensuring the strength of the screw shaft;

[0032] When the arm of the robot needs to be extended or shortened, the length and diameter of the shaft 4 can be adjusted. It is only necessary to replace the shaft 4 with a shaft of different length and diameter without replacing the entire screw shaft. Therefore, during manufacturing, it is only necessary to manufacture multiple shafts 4 or connectors 6 of different specifications, and the screw heads 2 can be universal. The number structure prepared for maintenance and replacement can save manufacturing costs and material costs compared to manufacturing the entire shaft.

[0033] During maintenance and replacement, only the damaged parts need to be replaced without replacing the entire screw shaft, which can save maintenance costs and improve resource utilization.

[0034] The embodiments are used to illustrate the present invention, but not to limit the present invention. Any person skilled in the art may modify the embodiments without violating the spirit and scope of the present invention, and therefore the scope of protection of the present invention shall be as set forth in the claims of the present invention.

Claims

1. A planetary roller screw for a robot arm, comprising an outer nut sleeve (1), wherein a screw shaft is inserted into the nut sleeve (1), and characterized in that: The screw shaft comprises a screw head (2), a shaft (4) and a connector (6); an annular retaining frame (5) is pivotally connected to both ends of the screw head (2); a plurality of planetary screw rollers (3) are inserted and connected between the retaining frames (5); the planetary screw rollers (3) are evenly distributed in an annular shape around the central axis of the screw head (2); and the threads on the planetary screw rollers (3) are respectively screwed to the threads on the inner wall of the nut sleeve (1) and the threads on the outer wall of the screw head (2); A cylindrical connecting seat (21) is formed at one end of the screw head (2), a D-shaped plug hole (22) is formed on the end surface of the end of the connecting seat (21), a center hole (23) penetrating the end surface of the other end of the screw head (2) is formed on the bottom surface of the D-shaped plug hole (22), and a concave platform (24) connected to the center hole (23) is formed on the end surface of the other end of the screw head (2); The end of the shaft (4) close to the screw head (2) is formed with a D-shaped limit plug (42), the limit plug (42) is inserted into the D-shaped socket (22) of the screw head (2) and is formed with a center axis (43), the center axis (43) passes through the center hole (23) of the screw head (2) and is clamped with a clamping ring (7), and the clamping ring (7) is inserted into the concave platform (24) of the screw head (2); A bottom threaded hole (45) is formed on the end surface of the shaft rod (4) facing away from the screw head (2), and a stud (62) is formed on the connecting head (6). The stud (62) is screwed into the bottom threaded hole (45) of the shaft rod (4), and the connecting head (6) is pressed against the end surface of the shaft rod (4).

2. The planetary roller screw for a robot arm according to claim 1, characterized in that: A countersunk hole (46) is formed on the shaft rod (4) at the entrance of the bottom threaded hole (45), and a spring washer (8) is inserted into the countersunk hole (46). The two end surfaces of the spring washer (8) are pressed against the shaft rod (4) and the connecting head (6) respectively; the spring washer (8) is inserted into the stud (62) of the connecting head (6), and a pin hole (61) is formed on the connecting head (6).

3. The planetary roller screw for a robot arm according to claim 1, characterized in that: The central axis of the screw shaft coincides with the central axis of the nut sleeve (1); two sets of central gear rings are formed on the screw head (2) of the screw shaft; planetary gear rings are formed on the outer walls of both ends of the planetary screw roller (3); and the planetary gear rings of the planetary screw roller (3) are respectively meshed with the central gear rings on the screw head (2); Support shafts (31) are formed at both ends of the planetary screw roller (3), and the support shafts (31) are respectively inserted into the retaining frame (5).

4. The planetary roller screw for a robot arm according to claim 3, characterized in that: A plurality of slots are formed on the outer wall of the screw head (2), and a retaining frame (5) is inserted into the slots of the screw head (2). The end surface of one end of the retaining frame (5) abuts against the side wall of the slot, and the other end abuts against a retaining spring (9), which is retained in the slot of the screw head (2).

5. The planetary roller screw for a robot arm according to claim 1, characterized in that: The diameter of the outer wall of the connecting seat (21) on the screw head (2) is larger than the diameter of the outer wall of the screw head (2) and smaller than the diameter of the inner wall of the nut sleeve (1); the diameter of the outer wall of the shaft (4) is not larger than the diameter of the outer wall of the connecting seat (21) and not smaller than the diameter of the outer wall of the limit plug (42).

6. The planetary roller screw for a robot arm according to claim 5, characterized in that: Limiting grooves (41) are formed on the outer walls on two opposite sides of the shaft rod (4).

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