Reverse circulation type planetary roller lead screw pair for linear joints of humanoid robot

Abstract

The utility model discloses a reverse circulation type planetary roller lead screw pair for a humanoid robot linear joint, which comprises a long nut, a lead screw, a roller and a retainer, the lead screw is coaxially arranged in the long nut, the part of the lead screw arranged in the long nut is provided with a threaded section, the retainer is sleeved between the lead screw and the long nut, and the roller is arranged in the long nut. An anti-falling mounting groove is formed in the retainer, and the pin roller is rotationally mounted in the anti-falling mounting groove; annular groove teeth are formed in the surface of the roller, one side of the outer wall of the roller is meshed with the internal thread on the inner wall of the long nut, and the other side of the outer wall of the roller is meshed with the threaded section on the lead screw. Circulating reset components are installed at the two ends of the threaded section of the lead screw respectively, and the two ends of the pin roller make contact with the circulating reset components respectively. Compared with a traditional pin roller, the pin roller with the annular groove teeth can reduce the manufacturing difficulty, is convenient to machine, is matched with a retainer of an integrated structure, can simplify the machining steps and reduces the assembly difficulty.

Description

Technical Field

[0001] The utility model relates to the technical field of lead screw transmission. Specifically, it is a reverse circulating planetary roller screw pair for a linear joint of a humanoid robot. Background Technique

[0002] A planetary roller screw pair is a rolling spiral transmission mechanism that converts linear motion and rotational motion into each other. It transmits power through multi-point thread contact between multiple rollers and the screw and nut raceways, and has the characteristics of a large number of contact points, large bearing capacity, and long service life.

[0003] In recent years, with the rapid development of humanoid robots, planetary roller screw pairs have begun to be applied in robot joints. Among them, the reverse planetary roller screw pair is the most common in humanoid robot joints. The reverse planetary roller screw pair is a derivative mechanism of the planetary roller screw pair. The difference is that the long nut of the reverse planetary roller screw pair is used as the driving part, and the screw is used as the linear output part. Moreover, the nut of the reverse planetary roller screw pair can be integrally designed with the motor, and the long nut is used as the motor rotor, so that the overall actuator is more compact. However, at the same time, the rollers of the reverse planetary roller screw pair not only have threads but also have thread teeth, and during processing, there are high processing accuracy requirements and cumbersome and complex processing steps and process requirements. Content of the Utility Model

[0004] Therefore, the technical problem to be solved by the present utility model is to provide a reverse circulating planetary roller screw pair for a linear joint of a humanoid robot that is easy to process.

[0005] To solve the above technical problem, the present utility model provides the following technical solution: A reverse circulating planetary roller screw pair for a linear joint of a humanoid robot, including a long nut, a screw, rollers, and a cage. The screw is coaxially arranged inside the long nut. A threaded section is arranged on the part of the screw arranged inside the long nut. The cage is sleeved between the screw and the long nut. An anti-drop installation groove is opened on the cage. The rollers are rotatably installed in the anti-drop installation groove. An annular groove tooth is opened on the surface of the rollers. One side of the outer wall of the rollers meshes with the internal thread on the inner wall of the long nut, and the other side of the outer wall of the rollers meshes with the threaded section on the screw. Circulating reset components are respectively installed at both ends of the threaded section on the screw. Both ends of the rollers are respectively in contact with the circulating reset components. A return groove is opened along the length direction on the threaded section.

[0006] The above-mentioned reverse-circulation planetary roller screw pair for a humanoid robot linear joint, on the cage, there are provided with more than three anti-falling mounting grooves equidistantly arranged in the circumferential direction, and each of the anti-falling mounting grooves is provided with the roller; in a plane perpendicular to the axis of the cage: the contour of the groove wall of the anti-falling mounting groove is circular arc-shaped, the width of the anti-falling mounting groove gradually becomes wider from the outside to the inside, and the outer width of the anti-falling mounting groove is smaller than the diameter of the roller.

[0007] The above-mentioned reverse-circulation planetary roller screw pair for a humanoid robot linear joint, on the inner side wall surface of the cage: a stop block is arranged between two adjacent anti-falling mounting grooves, the stop block is arranged along the axial direction of the cage, and the width of the stop block gradually becomes narrower from the side in contact with the cage to the side away from the cage.

[0008] The above-mentioned reverse-circulation planetary roller screw pair for a humanoid robot linear joint, the circulation reset component includes a first positioning ring, a first end face cam ring, a second positioning ring and a second end face cam ring, positioning platforms are arranged at both ends of the screw on the threaded section, the first positioning ring is coaxially fixed on the positioning platform at one end of the threaded section, the second positioning ring is coaxially fixed on the positioning platform at the other end of the threaded section, the first end face cam ring is coaxially fixedly installed on the first positioning ring, the second end face cam ring is coaxially installed on the second positioning ring, the first end face cam ring and the second end face cam ring are arranged oppositely, and the highest points of the first end face cam ring and the second end face cam ring are staggered; both ends of the cage are respectively rotatably sleeved on the first end face cam ring and the second end face cam ring.

[0009] The above-mentioned reverse-circulation planetary roller screw pair for a humanoid robot linear joint, pin holes are provided on both the first positioning ring and the second positioning ring, and pin holes are also provided on both of the positioning platforms, and the first positioning ring and the second positioning ring are respectively fixedly connected to the two positioning platforms through fixing pins.

[0010] The above-mentioned reverse-circulation planetary roller screw pair for a humanoid robot linear joint, the first end face cam ring and the second end face cam ring have the same structure, the second end face cam ring includes a spiral pushing section and a reset section, the lead of the spiral pushing section is smaller than the lead of the reset section, the spiral pushing section is arranged in a spiral shape along the end face of the second end face cam ring, and both ends of the spiral pushing section are respectively connected to both ends of the reset section.

[0011] The above-mentioned reverse-circulation planetary roller screw pair for a humanoid robot linear joint, the reset sections on the first end face cam ring and the second end face cam ring are respectively arranged on both sides of the return groove.

[0012] The above-mentioned reverse-circulation planetary roller screw pair for a humanoid robot linear joint is provided with an arc chamfer at the connecting part of the spiral pushing section and the reset section.

[0013] The above-mentioned reverse-circulation planetary roller screw pair for a humanoid robot linear joint has the same thread parameters on the inner wall of the long nut and the threaded section on the screw.

[0014] The above-mentioned reverse-circulation planetary roller screw pair for a humanoid robot linear joint has a return groove depth that is half of the minor diameter of the threaded section minus the tooth height of the annular groove teeth on one roller.

[0015] The technical solution of the present utility model has achieved the following beneficial technical effects:

[0016] 1. By providing rollers with annular groove teeth, compared with traditional rollers, the manufacturing difficulty can be reduced, facilitating processing. Cooperating with the cage of an integral structure can simplify the processing steps and reduce the assembly difficulty.

[0017] 2. The anti-falling installation groove of the cage is an arc surface groove and gradually narrows from the inside to the outside, enabling the rollers to be installed in one go. After removing the long nut, the rollers will not fall out, making the installation very convenient, facilitating assembly and maintaining the stability of the roller operation during the running process.

[0018] 3. By providing the first end face cam ring, the second end face cam ring and the return groove, the rollers can return to the initial position after rotating around the screw for one week, realizing the circulation of the rollers. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic cross-sectional structure diagram of the present utility model;

[0020] Figure 2 Exploded structure diagram of the present utility model;

[0021] Figure 3 Schematic side view structure diagram of the cage of the present utility model;

[0022] Figure 4 Schematic structure diagram of the screw of the present utility model;

[0023] Figure 5 Schematic three-dimensional structure diagram of the screw of the present utility model;

[0024] Figure 6 Schematic three-dimensional structure diagram of the second positioning ring of the present utility model;

[0025] Figure 7 Schematic end face structure diagram of the screw of the present utility model.

[0026] The reference numerals in the figure are indicated as follows: 1 - long nut; 2 - lead screw; 3 - roller; 4 - cage; 5 - anti-falling installation groove; 6 - first positioning ring; 7 - first end face cam ring; 8 - second positioning ring; 9 - second end face cam ring; 91 - spiral pushing section; 92 - reset section; 10 - arc chamfer; 11 - positioning table; 12 - pin hole; 13 - threaded section; 14 - stop block; 15 - fixing pin; 16 - return groove. Specific embodiments

[0027] A reverse circulating planetary roller screw pair for a humanoid robot linear joint in this embodiment is as Figure 1 , 2 and shown in Figure 5, and includes a long nut 1, a lead screw 2, rollers 3 and a cage 4. The lead screw 2 is coaxially arranged in the long nut 1. A threaded section 13 is provided on the part of the lead screw 2 arranged in the long nut 1. The cage 4 is sleeved between the lead screw 2 and the long nut 1. An anti-falling installation groove 5 is formed on the cage 4. The rollers 3 are rotatably installed in the anti-falling installation groove 5. An annular groove tooth is formed on the surface of the roller 3, that is, thread patterns are arranged along the circumferential direction of the roller 3 and there is no lead angle. The depth of the return groove 16 is half of the minor diameter of the threaded section 13 minus the tooth height of the annular groove tooth on one roller 3. The tooth height is the maximum outer diameter of the annular groove tooth. The thread parameters on the inner wall of the long nut 1 are the same as those of the threaded section 13 on the lead screw 2. One side of the outer wall of the roller 3 meshes with the internal thread on the inner wall of the long nut 1, and the other side of the outer wall of the roller 3 meshes with the threaded section 13 on the lead screw 2. By providing the roller 3 with annular groove teeth, compared with the traditional roller, the manufacturing difficulty can be reduced, which is convenient for processing. Cooperating with the integral structure of the cage 4, the processing steps can be simplified and the assembly difficulty can be reduced. Circulating reset components are respectively installed at both ends of the threaded section 13 on the lead screw 2. Both ends of the roller 3 are respectively in contact with the circulating reset components. A return groove 16 is formed along the length direction on the threaded section 13.

[0028] As Figures 2-3 shown, three or more anti-falling installation grooves 5 are circumferentially and equidistantly formed on the cage 4, and each anti-falling installation groove 5 is provided with the roller 3. In this embodiment, 5 anti-falling installation grooves 5 and 5 rollers 3 are adopted. In the rotation direction, the axial end face distance between each roller 3 and its adjacent previous roller 3 is where p hp is the pitch of the internal thread of the long nut 1 and the thread of the threaded section 13 on the lead screw 2, and N is the number of rollers 3; on a plane perpendicular to the axis of the cage 4: the contour of the groove wall of the anti-falling mounting groove 5 is arc-shaped, the width of the anti-falling mounting groove 5 gradually widens from the outside to the inside, and the outer width of the anti-falling mounting groove 5 is smaller than the diameter of the roller 3. The anti-falling mounting groove 5 of the cage 4 is an arc-shaped groove and gradually narrows from the inside to the outside, which can make the rollers 3 be installed at one time. After the long nut 1 is taken out, the rollers 3 will not fall out, and the installation is very convenient, which is convenient for assembly and maintains the stability of the rotation of the rollers 3 during operation.

[0029] As Figure 3 shown, on the inner side wall surface of the cage 4: a stop block 14 is arranged between two adjacent anti-falling mounting grooves 5. The stop block 14 is arranged along the axial direction of the cage 4, and the width of the stop block 14 gradually narrows from the side in contact with the cage 4 to the side away from the cage 4.

[0030] As Figures 4-5 shown, the circulating reset component includes a first positioning ring 6, a first end face cam ring 7, a second positioning ring 8 and a second end face cam ring 9. Positioning platforms 11 are arranged at both ends of the threaded section 13 on the lead screw 2. The first positioning ring 6 is coaxially fixed on the positioning platform 11 at one end of the threaded section 13, the second positioning ring 8 is coaxially fixed on the positioning platform 11 at the other end of the threaded section 13, the first end face cam ring 7 is coaxially fixed on the first positioning ring 6, the second end face cam ring 9 is coaxially installed on the second positioning ring 8. The first end face cam ring 7 and the second end face cam ring 9 are arranged opposite to each other, and the highest points of the first end face cam ring 7 and the second end face cam ring 9 are staggered; both ends of the cage 4 are rotatably sleeved on the first end face cam ring 7 and the second end face cam ring 9 respectively. By setting the first end face cam ring 7, the second end face cam ring 9 and the return groove 16, the rollers 3 can return to the initial position after rotating one week around the lead screw 2, realizing the circulation of the rollers 3.

[0031] As Figures 5-6 shown, pin holes 12 are opened on both the first positioning ring 6 and the second positioning ring 8, and pin holes 12 are also opened on both the two positioning platforms 11. The first positioning ring 6 and the second positioning ring 8 are respectively fixedly connected to the two positioning platforms 11 through fixing pins 15.

[0032] As Figure 4 and Figure 6As shown, the structures of the first end face cam ring 7 and the second end face cam ring 9 are the same. The second end face cam ring 9 includes a spiral pushing section 91 and a reset section 92. The lead of the spiral pushing section 91 is smaller than that of the reset section 92. The spiral pushing section 91 is arranged spirally along the end face of the second end face cam ring 9. The two ends of the spiral pushing section 91 are respectively connected to the two ends of the reset section 92. An arc chamfer 10 is provided at the connecting part of the spiral pushing section 91 and the reset section 92, which can avoid collision with the roller 3 and enable the roller 3 to move smoothly. The reset sections 92 on the first end face cam ring 7 and the second end face cam ring 9 are respectively arranged on both sides of the return groove 16.

[0033] Specific principle: 1. Movement of the long nut: The long nut 1 rotates under the drive of a drive source. The drive source, a permanent magnet or a frameless torque motor, applies power to the long nut 1, and the long nut 1 starts to rotate.

[0034] 2. Movement of the roller: ① The roller 3 meshes with the internal thread of the long nut 1 through its annular groove teeth without lead angle. During the rotation of the long nut 1, the power source transmits power to the roller 3 through the meshing threads, pushing each roller 3 to perform planetary motion, rotating around its own axis and revolving around the axis of the lead screw 2 at the same time. ② After the roller 3 rotates circumferentially around the threaded section 13 of the lead screw 2 for one week, through the pushing of the convex platforms on the first end face cam ring 7 and the second end face cam ring 9 and the cooperation with the non-threaded area return groove 16 on the threaded section 13, finally the roller 3 returns to its initial position relative to the threaded section 13 of the lead screw 2.

[0035] 3. Movement of the lead screw: After the power is transmitted to the roller 3, the roller 3 rotates and revolves, and transmits the power to the lead screw 2 through the thread meshing with the threaded section 13 of the lead screw 2, pushing the lead screw 2 to perform axial linear motion.

[0036] Obviously, the above embodiments are only examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom still fall within the protection scope of the claims of this patent application.

Claims

1. A reverse cyclic planetary roller screw pair for a linear joint of a humanoid robot, characterized in that, It includes a long nut (1), a lead screw (2), rollers (3) and a cage (4). The lead screw (2) is coaxially arranged inside the long nut (1). A threaded section (13) is provided on the part of the lead screw (2) arranged inside the long nut (1). The cage (4) is sleeved between the lead screw (2) and the long nut (1). An anti-falling installation groove (5) is formed on the cage (4). The rollers (3) are rotatably installed in the anti-falling installation groove (5). An annular groove tooth is formed on the surface of the roller (3). One side of the outer wall of the roller (3) meshes with the internal thread on the inner wall of the long nut (1), and the other side of the outer wall of the roller (3) meshes with the threaded section (13) on the lead screw (2). Circulating reset components are respectively installed at both ends of the threaded section (13) on the lead screw (2). Both ends of the roller (3) are respectively in contact with the circulating reset components. A return groove (16) is formed along the length direction on the threaded section (13).

2. The reverse circulating planetary roller screw pair for a humanoid robot linear joint according to claim 1, characterized in that, Three or more anti-falling installation grooves (5) are circumferentially and equidistantly formed on the cage (4). The rollers (3) are arranged in each anti-falling installation groove (5). On a plane perpendicular to the axis of the cage (4): the contour of the groove wall of the anti-falling installation groove (5) is arc-shaped, the width of the anti-falling installation groove (5) gradually becomes wider from the outside to the inside, and the outer width of the anti-falling installation groove (5) is smaller than the diameter of the roller (3).

3. The reverse cyclic planetary roller screw pair for a linear joint of a humanoid robot according to claim 2, characterized in that, On the inner side wall surface of the cage (4): a stop block (14) is arranged between two adjacent anti-falling installation grooves (5). The stop block (14) is arranged along the axial direction of the cage (4). The width of the stop block (14) gradually becomes narrower from the side in contact with the cage (4) to the side away from the cage (4).

4. The reverse cyclic planetary roller screw pair for a linear joint of a humanoid robot according to claim 1, wherein, The circulating reset component includes a first positioning ring (6), a first end face cam ring (7), a second positioning ring (8) and a second end face cam ring (9). Positioning platforms (11) are arranged at both ends of the threaded section (13) on the lead screw (2). The first positioning ring (6) is coaxially fixed on the positioning platform (11) at one end of the threaded section (13). The second positioning ring (8) is coaxially fixed on the positioning platform (11) at the other end of the threaded section (13). The first end face cam ring (7) is coaxially and fixedly installed on the first positioning ring (6). The second end face cam ring (9) is coaxially installed on the second positioning ring (8). The first end face cam ring (7) and the second end face cam ring (9) are arranged oppositely, and the highest points of the first end face cam ring (7) and the second end face cam ring (9) are staggered. Both ends of the cage (4) are respectively rotatably sleeved on the first end face cam ring (7) and the second end face cam ring (9).

5. A reverse cyclic planetary roller screw pair for a linear joint of a humanoid robot according to claim 4, characterized in that, The first positioning ring (6) and the second positioning ring (8) are both provided with pin holes (12), and the two positioning platforms (11) are also provided with pin holes (12). The first positioning ring (6) and the second positioning ring (8) are respectively fixedly connected to the two positioning platforms (11) through fixing pins (15).

6. The reverse cyclic planetary roller screw pair for a linear joint of a humanoid robot according to claim 4, wherein The first end face cam ring (7) and the second end face cam ring (9) have the same structure. The second end face cam ring (9) includes a spiral pushing section (91) and a reset section (92). The lead of the spiral pushing section (91) is smaller than the lead of the reset section (92). The spiral pushing section (91) is arranged in a spiral shape along the end face of the second end face cam ring (9), and the two ends of the spiral pushing section (91) are respectively connected to the two ends of the reset section (92).

7. A reverse cyclic planetary roller screw pair for a linear joint of a humanoid robot according to claim 6, characterized in that, The reset sections (92) on the first end face cam ring (7) and the second end face cam ring (9) are respectively arranged on both sides of the return groove (16).

8. A reverse cyclic planetary roller screw pair for a linear joint of a humanoid robot according to claim 6, characterized in that, An arc chamfer (10) is arranged at the connecting part of the spiral pushing section (91) and the reset section (92).

9. The reverse cyclic planetary roller screw pair for a linear joint of a humanoid robot according to claim 1, characterized in that, The thread parameters on the inner wall of the long nut (1) are the same as the thread parameters of the threaded section (13) on the lead screw (2).

10. A reverse cyclic planetary roller screw pair for a linear joint of a humanoid robot according to claim 1, characterized in that, The depth of the return groove (16) is half of the minor diameter of the threaded section (13) minus the tooth height of the annular groove teeth on a roller (3).

Images