Split type wedge-shaped contact planetary roller lead screw pair

Abstract

The invention discloses a split type wedge-shaped contact planetary roller lead screw pair, and relates to the technical field of precision lead screws. Comprising a reverse type nut, a retainer is arranged in the reverse type nut, a plurality of split type rollers are evenly connected to the retainer in the circumferential direction, the reverse type nut is in threaded connection with the split type rollers, a split type lead screw is arranged in an area surrounded by the split type rollers, and the split type rollers are in threaded connection with the split type lead screw. The two ends of the split type lead screw are connected with a first split type gear ring and a second split type gear ring in a self-locking mode, the first split type gear ring and the second split type gear ring are fixedly connected with the retainers at the two ends of the split type pin roller respectively, the second split type gear ring is connected with a push rod, and the push rod extends out of a reverse type nut. The end, penetrated by the push rod, of the reverse nut is fixedly connected with a supporting sleeve. The reverse planetary roller lead screw pair is high in integration level and ingenious in layout, the bearing performance, the transmission performance, the reliability and other service performance of the reverse planetary roller lead screw pair are improved, and the overall machining process, the price cost and the assembly difficulty of the lead screw pair are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of precision screws, and in particular to a split wedge-shaped contact planetary roller screw pair. Background Art

[0002] With the development of linear electric drive joints of humanoid robots, the reverse planetary roller screw pair has gradually attracted the attention of the engineering and technical fields of various countries due to its high precision, small size and large load-bearing capacity. Relevant studies have shown that the use of reverse planetary roller screw pairs in humanoid robot joint actuators can significantly improve the system's operating accuracy and stability, while effectively avoiding the problems of large transmission clearance and fast wear in traditional screw pairs. Therefore, how to optimize the design and low-cost processing of reverse planetary roller screw pairs while ensuring high reliability and long life has become an important research direction for high thrust density and high force-to-weight ratio linear electric drive actuators for humanoid robots.

[0003] In addition to humanoid robots, the electric steering system and suspension system of new energy vehicles also require a stable transmission mechanism to meet complex working conditions such as strong vibration, wear resistance, and fast response. Nowadays, the screw pair used in new energy vehicles will have a series of problems such as jamming, complex processing technology, and large transmission gap during the test process. In the above context, it is particularly important to study a split wedge contact planetary roller screw pair.

[0004] As for the current structural design of the reverse planetary roller screw pair, the straight teeth and thread integrated structure on the screw is generally adopted at home and abroad, and most of them are based on the separate selection of nuts and bearings. Although the function of telescopic transmission can be realized, it will lead to the overall mechanism being large in size, high in cost, and short in life. Therefore, it is urgent to design a small-volume, low-cost, long-life split wedge-shaped contact planetary roller screw pair to realize the upgrade and transformation of the core transmission mechanism of humanoid robots and new energy vehicles. Summary of the invention

[0005] The main purpose of the present invention is to provide a split wedge-shaped contact planetary roller screw pair to solve the problems existing in the prior art.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A split wedge-contact planetary roller screw pair comprises a reverse nut, a retaining frame is arranged inside the reverse nut, a plurality of split rollers are evenly connected to the retaining frame in a circumferential direction, the reverse nut is threadedly connected to the plurality of split rollers through an internal thread, a split screw is arranged inside the area surrounded by the plurality of split rollers, each of the split rollers is threadedly connected to the split screw, a split gear ring 1 and a split gear ring 2 are respectively self-lockingly connected at both ends of the split screw, the split gear ring 1 and the split gear ring 2 are respectively fixedly connected to the retaining frames at both ends of the split rollers, a push rod is fixedly connected to the split gear ring 2, the end of the push rod extends out of the reverse nut, and the end of the reverse nut penetrated by the push rod is fixedly connected to a support sleeve.

[0008] Furthermore, the split roller includes a middle thread of the split roller, spur teeth at the left end of the split roller and spur teeth at the right end of the split roller, the spur teeth at the left end of the split roller and the spur teeth at the right end of the split roller are respectively connected to the two ends of the middle thread of the split roller, the reverse nut is meshed with the middle thread of the split roller, the spur teeth at the left end of the split roller and the spur teeth at the right end of the split roller through an internal thread, the middle thread of the roller is meshed with the external thread of the split screw, and the helix angle of the middle thread of the split roller and the external thread of the split screw are the same.

[0009] Furthermore, the retaining frame is clearance-matched with the shaft end of the split roller; and the supporting sleeve is clearance-matched with the push rod.

[0010] Furthermore, the split gear ring 1 and the split gear ring 2 are fixedly connected to the retaining frames at both ends of the split roller through supporting retaining rings respectively.

[0011] Furthermore, wedge-shaped conical surfaces are provided at both ends of the split screw, and the split gear ring 1 and the split gear ring 2 are provided with inner conical surfaces adapted to the wedge-shaped conical surfaces, and the wedge-shaped conical surfaces at both ends are in wedge-shaped contact with the inner conical surfaces of the split gear ring 1 and the split gear ring 2 respectively, and a gap is left between the wedge-shaped conical surface and the split gear ring 1 or the split gear ring 2.

[0012] Furthermore, the complete tooth width of the spur teeth at the left end of the split roller and the spur teeth at the right end of the split roller should be 1.2-1.5 times the width of the spur teeth of the split gear ring one and the split gear ring two, respectively.

[0013] Furthermore, the reverse nut includes a front end outer circle and a bearing, and the front end outer circle and the bearing are an integrated structure.

[0014] Furthermore, an annular glue guiding groove is provided on the outer peripheral side of the inverted nut, and the inverted nut is connected to the hollow cup motor through the annular glue guiding groove.

[0015] Furthermore, the rotation direction of the internal thread of the reverse nut is opposite to the rotation direction of the external thread of the split roller, and the rotation direction of the internal thread of the reverse nut is the same as the rotation direction of the external thread of the split screw.

[0016] Furthermore, the split gear ring 2 is clearance-matched with the push rod, and the split gear ring 2 and the push rod are fixedly connected via four fixing pins, the fixing pins have a wedge-shaped plane, and the split gear ring 2 and the push rod are connected via the fixing pins in a conical interlocking manner.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The structure of the present invention is more compact, the overall volume is small, the manufacturing cost is low, and the service life is long.

[0019] 2. The use of split screw and split gear ring as the main transmission components reduces the difficulty of processing and heat treatment and improves the load-bearing capacity, while ensuring its reliability during the working process, meeting the low-cost domestic substitution of screw products for high-end equipment.

[0020] 3. The two ends of the split screw are connected with the split gear ring through a wedge-shaped cone surface, which not only increases the self-locking function of the two and improves the operating reliability, but also increases the adjustable contact surface function when the thread and gear are engaged at the same time, and improves the transmission performance when the gear pair and the thread pair are engaged.

[0021] 4. The split gear ring and push rod adopt a wedge-shaped contact design, which reduces the risk of friction, wear and loosening caused by repeated axial loads, provides precise axial positioning and improves the reliability and service life of the overall reverse planetary roller screw pair. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention is a cross-sectional view of a split wedge-shaped contact planetary roller screw pair.

[0023] Figure 2 This is a partial enlarged view of the split roller area of ​​a split wedge-shaped contact planetary roller screw pair of the present invention.

[0024] Figure 3 The present invention provides a split roller front view of a split wedge-shaped contact planetary roller screw pair.

[0025] Figure 4 The present invention is a front view of a reverse nut of a split wedge-shaped contact planetary roller screw pair.

[0026] Figure 5The isometric view of a split gear ring 1 of a split wedge-shaped contact planetary roller screw pair of the present invention.

[0027] Figure 6 The isometric view of the split gear ring 2 of the split wedge-shaped contact planetary roller screw pair of the present invention.

[0028] Among them: 1. Reverse nut; 1-1. One-piece bearing inner ring; 1-2. Annular rubber guide groove; 2. Split roller; 2-1. Straight teeth on the left end of the split roller; 2-2. Middle thread of the split roller; 2-3. Straight teeth on the right end of the split roller; 3. Split screw; 4. Cage; 5. Support retaining ring; 6. Split gear ring 1; 7. Split gear ring 2; 8. Fixing pin; 9. Push rod; 10. Support sleeve. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0030] Example 1

[0031] Combination Figure 1-6 The present invention provides a split wedge-shaped contact planetary roller screw pair, comprising a reverse nut 1, a retaining frame 4 is arranged inside the reverse nut 1, and a plurality of split rollers 2 are evenly connected to the retaining frame 4 along the circumferential direction, the reverse nut 1 is threadedly connected to the plurality of split rollers 2 through internal threads, a split screw 3 is arranged inside the area surrounded by the plurality of split rollers 2, each of the split rollers 2 is threadedly connected to the split screw 3, and the split screw 3 The two ends are respectively self-lockingly connected with a split gear ring 1 6 and a split gear ring 2 7, and the split gear ring 1 6 and the split gear ring 2 7 are respectively fixedly connected to the retaining frames 4 at both ends of the split roller 2, and the split gear ring 2 7 is fixedly connected with a push rod 9, and the end of the push rod 9 extends out of the reverse nut 1, and the end of the reverse nut 1 penetrated by the push rod 9 is fixedly connected with a support sleeve 10. In this embodiment, the support sleeve 10 is fixed to the reverse nut 1 by gluing.

[0032] The split roller 2 includes a split roller middle thread 2-2, a split roller left end spur tooth 2-1 and a split roller right end spur tooth 2-3, the split roller left end spur tooth 2-1 and the split roller right end spur tooth 2-3 are respectively connected to the two ends of the split roller middle thread 2-2, the reverse nut 1 is meshed with the split roller middle thread 2-2, the split roller left end spur tooth 2-1 and the split roller right end spur tooth 2-3 through the internal thread, the roller middle thread 2-2 is meshed with the external thread of the split screw 3, the split roller middle thread 2-2 and the split screw 3 external thread have the same helix angle, which ensures that the split roller 2 not only rolls along the spiral raceway of the split screw 3 and the reverse nut 1, but also rotates around its own axis and the center axis of the split screw 3.

[0033] The retaining frame 4 is clearance-matched with the axial end of the split roller 2 ; the supporting sleeve 10 is clearance-matched with the push rod 9 .

[0034] The split gear ring 1 6 and the split gear ring 2 7 are fixedly connected to the retaining frames 4 at both ends of the split roller 2 through supporting retaining rings 5 ​​respectively.

[0035] The two ends of the split screw 3 are provided with wedge-shaped conical surfaces, and the split gear ring 1 6 and the split gear ring 2 7 are provided with inner conical surfaces adapted to the wedge-shaped conical surfaces. The wedge-shaped conical surfaces at the two ends are in wedge-shaped contact with the inner conical surfaces of the split gear ring 1 6 and the split gear ring 2 7 respectively, and have a self-locking function. A gap is left between the wedge-shaped conical surface and the split gear ring 1 6 or the split gear ring 2 7, so as to facilitate the adjustment of the coaxiality of the straight teeth on the split gear ring 1 6 and the split gear ring 2 7 and the threads on the split screw 3.

[0036] The complete tooth width of the spur teeth 2-1 at the left end of the split roller and the spur teeth 2-3 at the right end of the split roller should be 1.2-1.5 times the width of the spur teeth of the split gear ring 1 6 and the split gear ring 2 7 respectively; the split roller 2 is generally a single-start thread, and the number distributed around the split lead screw 3 is generally 6-11, and the number of split rollers 2 is finally determined by the external load and the circumferential size. The number of threads of the split roller 2 is determined by the external load and the nominal size. The more threads there are, the better the rigidity is, but the higher the nonlinearity of the load distribution is.

[0037] An annular rubber guiding groove 1 - 2 is provided on the outer peripheral side of the inverted nut 1 , and the inverted nut 1 is connected to the coreless motor via the annular rubber guiding groove 1 - 2 .

[0038] The split gear ring 2 7 is clearance-fitted with the push rod 9, and the split gear ring 2 7 and the push rod 9 are fixedly connected by four fixing pins 8, the fixing pins 8 have a wedge-shaped plane, and the split gear ring 2 7 and the push rod 9 are connected by a conical surface interlocking type through the fixing pins 8. The push rod 9 and the split gear ring 2 7 will continuously bear reciprocating axial force during use, and the contact of the wedge-shaped plane can reduce the friction and wear of the mating surface and provide reliable axial positioning, thereby preventing the fixing pins 8 from accidentally loosening during operation.

[0039] The reverse nut 1 includes a front end outer circle and a bearing, and the front end outer circle and the bearing are integrated into a structure to form an integrated bearing inner ring 1-1. The internal thread of the reverse nut 1 is a multi-start structure. The number of thread heads depends on the process and load-bearing performance, and is generally 3 or 4 heads. In this embodiment, it is 4 heads. The rotation direction of the internal thread of the reverse nut 1 is opposite to the rotation direction of the external thread of the split roller 2, and the rotation direction of the internal thread of the reverse nut 1 is the same as the rotation direction of the external thread of the split screw 3.

[0040] As an optimization, a small section of the plane is milled off the upper end surface of the push rod 9 to form an anti-torsion portion, which forms a circumferential anti-torsion mechanism with the support sleeve 10.

[0041] When the split wedge-contact planetary roller screw pair is running, the external hollow cup motor is attached to the annular rubber guide groove 1-2 on the outer circle of the reverse nut 1, and the hollow cup motor drives the reverse nut 1 to rotate circumferentially. The reverse nut 1 drives the split roller 2 to rotate on itself and the split roller 2 to revolve around the split screw 3 with the retaining frame 4 through the internal thread and the meshing of the straight teeth; the middle thread 2-2 of the split roller and the external thread of the split screw 3 are meshed to make the split screw 3 do axial reciprocating movement, and drive the push rod 9 to do axial reciprocating movement through the split gear ring 2 7.

[0042] The split type means that the thread and spur tooth parts on the split lead screw 3 adopt a split design, which is replaced by the split lead screw 3 and two split gear rings, thereby increasing the adjustable function of the contact surface when the thread and the gear are double-pair meshing, and reducing the difficulty of the lead screw processing procedure, heat treatment and overall assembly.

[0043] The wedge contact is achieved by connecting the wedge-shaped conical surfaces at both ends of the split screw 3 with the inner conical surface of the split gear ring wedge, which enhances the self-locking function and operational reliability of the contact area. The split gear ring 2 7 and the push rod 9 adopt a conical surface mosaic design to reduce the risk of friction, wear and loosening caused by repeated axial loads, and improve the precise axial positioning capability.

[0044] The invention has high integration and ingenious layout, which not only improves the service performance of the reverse planetary roller screw pair such as load-bearing, transmission and reliability, but also reduces the overall processing technology, price cost and assembly difficulty of the screw pair.

[0045] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A split wedge-shaped contact planetary roller screw pair, characterized in that: The invention comprises a reverse nut (1), wherein a retaining frame (4) is arranged inside the reverse nut (1), and a plurality of split rollers (2) are evenly connected to the retaining frame (4) along the circumferential direction; the reverse nut (1) is threadedly connected to the plurality of split rollers (2) via internal threads; a split lead screw (3) is arranged inside the area surrounded by the plurality of split rollers (2); each of the split rollers (2) is threadedly connected to the split lead screw (3); and the split lead screw (3) is threadedly connected to the plurality of split rollers (2). ) are respectively self-lockingly connected with a split gear ring 1 (6) and a split gear ring 2 (7) at both ends of the split roller (2), the split gear ring 1 (6) and the split gear ring 2 (7) are respectively fixedly connected to the retaining frames (4) at both ends of the split roller (2), the split gear ring 2 (7) is fixedly connected with a push rod (9), the end of the push rod (9) extends out of the reverse nut (1), and the end of the reverse nut (1) penetrated by the push rod (9) is fixedly connected with a support sleeve (10).

2. A split wedge-contact planetary roller screw pair as claimed in claim 1, characterized in that: The split roller (2) comprises a split roller middle thread (2-2), a split roller left end spur tooth (2-1) and a split roller right end spur tooth (2-3), the split roller left end spur tooth (2-1) and the split roller right end spur tooth (2-3) are respectively connected to the two ends of the split roller middle thread (2-2), the reverse nut (1) is meshed with the split roller middle thread (2-2), the split roller left end spur tooth (2-1) and the split roller right end spur tooth (2-3) through an internal thread, the roller middle thread (2-2) is meshed with the external thread of the split screw (3), and the split roller middle thread (2-2) and the external thread of the split screw (3) have the same helix angle.

3. A split wedge-shaped contact planetary roller screw pair as claimed in claim 1, characterized in that: The retaining frame (4) is clearance-matched with the shaft end of the split roller (2); and the supporting sleeve (10) is clearance-matched with the push rod (9).

4. A split wedge-shaped contact planetary roller screw pair as claimed in claim 1, characterized in that: The split gear ring 1 (6) and the split gear ring 2 (7) are respectively fixedly connected to the retaining frames (4) at both ends of the split roller (2) through supporting retaining rings (5).

5. A split wedge-contact planetary roller screw pair as claimed in claim 1, characterized in that: The two ends of the split screw (3) are provided with wedge-shaped conical surfaces, and the split gear ring 1 (6) and the split gear ring 2 (7) are provided with inner conical surfaces adapted to the wedge-shaped conical surfaces. The wedge-shaped conical surfaces at the two ends are in wedge-shaped contact with the inner conical surfaces of the split gear ring 1 (6) and the split gear ring 2 (7), respectively, and a gap is left between the wedge-shaped conical surface and the split gear ring 1 (6) or the split gear ring 2 (7).

6. A split wedge-contact planetary roller screw pair as claimed in claim 1, characterized in that: The complete tooth width of the spur teeth (2-1) at the left end of the split roller and the spur teeth (2-3) at the right end of the split roller should be 1.2-1.5 times the spur tooth width of the split gear ring one (6) and the split gear ring two (7) respectively.

7. A split wedge-contact planetary roller screw pair as claimed in claim 1, characterized in that: The reverse nut (1) comprises a front end outer circle and a bearing, and the front end outer circle and the bearing are an integral structure.

8. A split wedge-shaped contact planetary roller screw pair as claimed in claim 1, characterized in that: An annular rubber guide groove (1-2) is provided on the outer peripheral side of the inverted nut (1), and the inverted nut (1) is connected to the coreless cup motor via the annular rubber guide groove (1-2).

9. A split wedge-contact planetary roller screw pair as claimed in claim 1, characterized in that: The rotation direction of the internal thread of the reverse nut (1) is opposite to the rotation direction of the external thread of the split roller (2), and the rotation direction of the internal thread of the reverse nut (1) is the same as the rotation direction of the external thread of the split screw (3).

10. A split wedge-contact planetary roller screw pair as claimed in claim 1, characterized in that: The split gear ring 2 (7) and the push rod (9) are clearance-matched, and the split gear ring 2 (7) and the push rod (9) are fixedly connected via four fixing pins (8), wherein the fixing pins (8) have wedge-shaped planes, and the split gear ring 2 (7) and the push rod (9) are connected via the fixing pins (8) in a conical interlocking manner.

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