Integrated reverse planetary roller screw structure

Abstract

The invention relates to the field of mechanical transmission parts, and particularly discloses an integrated reverse planetary roller screw structure which comprises a transmission roller, a moving screw and a retainer, the transmission roller comprises a transmission part and a limiting part, the transmission part is a cylinder with threads distributed on the peripheral surface, the limiting part is a cylinder with the peripheral surface arranged smoothly, the retainer is a hollow cylinder, and the moving screw is arranged on the transmission part. The holder comprises a holding end, a transmission area and a movement area, the transmission area is arranged on the peripheral face of the holder, the movement area penetrates through the axial center of the holder, the movement lead screw rotates in the movement area in a limited mode, the transmission part rotates in the transmission area in a limited mode, the holding end is provided with a limiting groove, and the limiting part rotates in the limiting groove in a limited mode. Straight teeth of the transmission pin roller are omitted, the transmission pin roller is integrally limited through the retainer, the synchronism of the two ends of the transmission pin roller is guaranteed, slight clamping stagnation of the pin roller during rotation is avoided, the transmission stability is improved, and the overall structure is simplified.

Description

Technical Field

[0001] The invention relates to the field of mechanical transmission components, and in particular to a planetary roller screw structure. Background Art

[0002] Planetary roller screw is a mechanical transmission device that can convert rotational motion and linear motion into each other. It has the comprehensive characteristics of thread transmission and rolling screw transmission. Compared with ball screw transmission, its rolling elements are not multiple spheres, but multiple rollers with threads.

[0003] The existing reverse planetary roller screw structure ensures that the roller axis is parallel to the screw axis and rolls normally by meshing the spur teeth at both ends of the roller with the spur teeth of the screw. In order to position the roller and realize the overall rotation, retaining frames are respectively provided at both ends of the roller, and the retaining frames are not connected to each other. Due to the transmission gap during the screw transmission, there is still a slight asynchronism between the retaining frames at both ends of the roller, which causes a slight tilt at both ends of the roller, resulting in a slight jamming of the roller when rotating.

[0004] The technical problem to be solved by the present application is: how to improve the synchronization between the two ends of the roller. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, an object of the present invention is to provide an integrated reverse planetary roller screw structure.

[0006] The technical solution adopted in the present invention is: an integrated reverse planetary roller screw structure, including a transmission roller, a moving screw and a retaining frame, the transmission roller includes a transmission part and a limiting part, the transmission part is a cylinder with threads on the outer circumference, the limiting part is a cylinder with a smooth outer circumference, the retaining frame is a hollow cylinder, the retaining frame includes a retaining end, a transmission area and a moving area, the transmission area is arranged on the outer circumference of the retaining frame, the moving area is through the axial center of the retaining frame, the moving screw is limited to rotate in the moving area, the transmission part is limited to rotate in the transmission area, the retaining end is provided with a limiting groove, and the limiting part is limited to rotate in the limiting groove.

[0007] The transmission roller has eliminated the straight tooth part and limits the transmission roller through the limit groove of the retaining frame, thereby ensuring that the axis of the transmission roller is parallel to the axis of the moving screw and rolls normally. Moreover, since the retaining frame is set as an integral part, the overall rotation of the retaining frame is guaranteed, thereby improving the synchronization of the two ends of the roller. The setting of the transmission area and the moving area ensures the normal rotation of the transmission roller and the moving screw.

[0008] In some embodiments, a nut is included, the length of the nut is greater than the length of the transmission roller, and the transmission roller, the moving screw and the retaining frame are axially displaced in the nut.

[0009] In some embodiments, a plurality of drive rollers are evenly distributed on the outer peripheral surface of the moving lead screw, and the drive rollers are in threaded engagement with the inner wall of the nut.

[0010] In some embodiments, limiting portions are respectively provided at both ends of the drive roller, and the diameter of the driving portion is larger than the diameter of the limiting portion.

[0011] In some embodiments, the moving lead screw includes a moving portion, the moving portion is in threaded engagement with the driving portion, and the lengths of the moving portion and the driving portion are the same.

[0012] In some embodiments, the number of drive rollers rotating in each drive zone is the same.

[0013] In some embodiments, two retaining end heads are provided at both ends of the cage, the limiting grooves corresponding to the two retaining end heads are arranged on the same straight line, and the driving portion is restricted between the two retaining end heads.

[0014] In some embodiments, the cage includes connecting columns, and a plurality of connecting columns are used to connect the two retaining end heads, and the connecting columns separate the respective drive zones.

[0015] In some embodiments, movable end caps and fixed end caps are respectively provided at both ends of the cage, the fixed end cap and the movable end cap are respectively abutted against the cage, the fixed end cap is fixedly arranged on the outer peripheral surface of the moving lead screw, and the movable end cap is movably arranged on the outer peripheral surface of the moving lead screw.

[0016] In some embodiments, a fixing groove and a shaft retaining ring are provided on the side of the movable end cap away from the cage, the fixing groove is fixedly arranged on the outer peripheral surface of the moving lead screw, and the shaft retaining ring is embedded in the fixing groove and one end of the shaft retaining ring abuts against the movable end cap.

[0017] The beneficial effects of the present invention are as follows:

[0018] In this integrated reverse planetary roller screw structure, by canceling the straight teeth of the drive rollers and the integral cage for limiting the drive rollers, since the cage rotates as a whole, the slight asynchrony between the two ends of the drive rollers is avoided, the synchronism of the two ends of the drive rollers is ensured, the slight jamming that may occur when the rollers rotate is avoided, the transmission smoothness is improved, and the overall structure is simplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0020] Figure 2 is a schematic cross-sectional view of the overall structure of the present invention;

[0021] Figure 3 is a schematic diagram of the connection structure of the drive roller, the drive roller and the cage;

[0022] Figure 4 Exploded view of the structure of the drive roller, drive roller and cage

[0023] The reference numerals in the figure correspond to the names as follows: 1. Drive roller; 2. Moving lead screw; 3. Cage; 4. Nut; 11. Driving part; 12. Limiting part; 21. Moving part; 22. Movable end cap; 23. Fixed end cap; 24. Fixed groove; 25. Shaft retaining ring; 31. Retaining end; 32. Connecting column; 33. Driving area; 34. Moving area; 35. Limiting groove Specific embodiments

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention

[0025] Please refer to Figure 1 , the present invention provides a technical solution: an integrated reverse planetary roller screw structure, including a drive roller 1, a moving lead screw 2, a cage 3 and a nut 4. A plurality of drive rollers 1 are evenly distributed on the outer peripheral surface of the moving lead screw 2. The drive rollers 1 are assembled on the cage 3. The inner wall of the nut 4 is covered with threads. The drive rollers 1 are in threaded engagement with the inner wall of the nut 4. There is no relative axial displacement between the drive rollers 1 and the moving lead screw 2. The length of the nut 4 is greater than the length of the drive rollers 1. The drive rollers 1, the moving lead screw 2 and the cage 3 perform axial displacement in the nut 4

[0026] Please refer to Figures 2 - 4 , the drive roller 1 includes a driving part 11 and a limiting part 12. The driving part 11 is arranged in the middle of the moving lead screw 2. Limiting parts 12 are respectively arranged at both ends of the drive roller 1. The driving part 11 is a cylinder with threads on its outer peripheral surface. The limiting part 12 is a cylinder with a smooth outer peripheral surface. The driving part 11 and the limiting part 12 are fixedly connected and integrally formed. The diameter of the driving part 11 is greater than the diameter of the limiting part 12

[0027] The moving lead screw 2 includes a moving part 21. The moving part 21 is arranged at one end of the moving lead screw 2. The moving part 21 is a cylinder with threads on its outer peripheral surface. The moving part 21 is in threaded engagement with the driving part 11 of the drive roller 1. The lengths of the moving part 21 and the driving part 11 are the same

[0028] Please refer to Figures 2 - 4, the cage 3 is a hollow cylinder. The cage 3 includes retaining ends 31, connecting columns 32, a transmission area 33, and a movement area 34. Two retaining ends 31 are provided at both ends of the cage 3. A number of connecting columns 32 are used to connect the two retaining ends 31. The connecting columns 32 and the retaining ends 31 form the main shape of the cage 3. The transmission area 33 is provided on the outer peripheral surface of the cage 3. The transmission area 33 communicates with the outside space and the movement area 34. The movement area 34 runs through the axial center of the cage 3. The transmission area 33 and the movement area 34 are in communication. The connecting columns 32 separate the respective transmission areas 33. The transmission parts 11 of the transmission rollers 1 are rotationally limited within the transmission areas 33. The number of transmission rollers 1 rotating within each transmission area 33 is the same to ensure that the cage 3 can rotate smoothly. The movement part 21 of the movement lead screw 2 is rotationally limited within the movement area 34. Moreover, since the movement area 34 and the transmission are in communication, it does not affect the meshing transmission between the transmission part 11 and the movement part 21. The retaining ends 31 are provided with limiting grooves 35, and the limiting grooves 35 corresponding to the two retaining ends 31 are arranged on the same straight line. The groove diameter of the limiting groove 35 is smaller than the cross-sectional area of the transmission area 33. The number of limiting grooves 35 is the same as that of the rollers. The limiting parts 12 of the rollers are rotationally limited within the limiting grooves 35. The groove diameter of the limiting part 12 is smaller than the diameter of the transmission part 11. Therefore, the transmission parts 11 of the rollers are restricted between the two retaining ends 31. The transmission rollers 1 expose threaded surfaces on the outer surfaces in the transmission areas 33 to ensure threaded engagement with the nut 4.

[0029] Please refer to Figures 2 - 4 , in order to limit the axial movement between the cage 3 and the movement lead screw 2, movable end caps 22 and fixed end caps 23 are respectively provided at both ends of the cage 3. The fixed end cap 23 and the movable end cap 22 are respectively in contact with the cage 3. Therefore, the fixed end cap 23 and the movable end cap 22 are respectively arranged at both ends of the movement part 21. The fixed end cap 23 is fixedly arranged on the outer peripheral surface of the movement lead screw 2. The movable end cap 22 is movably arranged on the outer peripheral surface of the movement lead screw 2. For the convenience of assembly, one fixed end cap 23 and one movable end cap 22 are provided on the movement lead screw 2. In order for the movable end cap 22 to maintain the contact relationship with the cage 3, a fixed groove 24 and a shaft retaining ring 25 are provided on the side of the movable end cap 22 away from the cage 3. The fixed groove 24 is fixedly arranged on the outer peripheral surface of the movement lead screw 2. The shaft retaining ring 25 is embedded in the fixed groove 24 and one end of the shaft retaining ring 25 is in contact with the movable end cap 22. The cooperation between the shaft retaining ring 25 and the fixed groove 24 can limit the axial movement of the movable end cap 22.

[0030] Since the cage 3 is integrally provided and the cage 3 rotates as a whole, it avoids the slight asynchrony between the two ends of the transmission roller 1, ensures the synchronism of the two ends of the transmission roller 1, avoids the slight jamming that may occur when the roller rotates, and improves the transmission smoothness.

[0031] Finally, it should be noted that the above are only preferred examples of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An integrated reverse planetary roller screw structure, characterized in that, It includes a transmission roller (1), a motion lead screw (2) and a cage (3). The transmission roller (1) includes a transmission part (11) and a limiting part (12). The transmission part (11) is a cylinder with a threaded outer peripheral surface, and the limiting part (12) is a cylinder with a smooth outer peripheral surface. The cage (3) is a hollow cylinder, and the cage (3) includes a holding end (31), a transmission area (33) and a motion area (34). The transmission area (33) is arranged on the outer peripheral surface of the cage (3), and the motion area (34) penetrates through the axial center of the cage (3). The motion lead screw (2) is rotationally limited in the motion area (34), the transmission part (11) is rotationally limited in the transmission area (33), the holding end (31) is provided with a limiting groove (35), and the limiting part (12) is rotationally limited in the limiting groove (35).

2. The integrated reverse planetary roller screw structure according to claim 1, characterized in that, It includes a nut (4). The length of the nut (4) is greater than the length of the transmission roller (1). The transmission roller (1), the motion lead screw (2) and the cage (3) perform axial displacement within the nut (4).

3. The integrated reverse planetary roller screw structure according to claim 2, characterized in that, A plurality of the transmission rollers (1) are evenly distributed on the outer peripheral surface of the motion lead screw (2), and the transmission rollers (1) are in threaded engagement with the inner wall of the nut (4).

4. The integrated reverse planetary roller screw structure according to claim 1, characterized in that Limiting parts (12) are respectively arranged at both ends of the transmission roller (1), and the diameter of the transmission part (11) is greater than the diameter of the limiting part (12).

5. The integrated reverse planetary roller screw structure according to claim 1, characterized in that The motion lead screw (2) includes a motion part (21). The motion part (21) is in threaded engagement with the transmission part (11), and the lengths of the motion part (21) and the transmission part (11) are the same.

6. The integrated reverse planetary roller screw structure according to claim 1, characterized in that, The number of the transmission rollers (1) rotating in each transmission area (33) is the same.

7. The integrated reverse planetary roller screw structure according to claim 1, characterized in that, Two of the holding ends (31) are arranged at both ends of the cage (3). The corresponding limiting grooves (35) of the two holding ends (31) are arranged on the same straight line, and the transmission part (11) is restricted between the two holding ends (31).

8. The integrated reverse planetary roller screw structure according to claim 1, characterized in that, The cage (3) includes connecting columns (32). A plurality of the connecting columns (32) are used to connect the two holding ends (31), and the connecting columns (32) separate each transmission area (33).

9. The integrated reverse planetary roller screw structure according to claim 1, characterized in that, Moving end caps (22) and fixed end caps (23) are respectively arranged at both ends of the cage (3). The fixed end cap (23) and the moving end cap (22) are respectively in contact with the cage (3). The fixed end cap (23) is fixedly arranged on the outer peripheral surface of the motion lead screw (2), and the moving end cap (22) is movably arranged on the outer peripheral surface of the motion lead screw (2).

10. The integrated reverse planetary roller screw structure according to claim 9, characterized in that, A fixed groove (24) and a shaft retaining ring (25) are arranged on the side of the moving end cap (22) away from the cage (3). The fixed groove (24) is fixedly arranged on the outer peripheral surface of the motion lead screw (2), and the shaft retaining ring (25) is embedded in the fixed groove (24) and one end of the shaft retaining ring (25) is in contact with the moving end cap (22).

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