Gearless planetary roller screw

Abstract

The invention relates to the technical field of planetary roller screws, in particular to a gearless planetary roller screw which comprises a nut, a screw body and rollers, and a multi-groove retainer is arranged between the nut and the screw body; when the lead screw is a driving part, one of the assembling section and the nut is provided with annular teeth, the other one of the assembling section and the nut is correspondingly provided with annular grooves, and the annular grooves are matched with the annular teeth, so that no relative axial displacement exists between the pin rollers and the nut; when the nut is a driving part, one of the assembling section and the lead screw is provided with at least one annular tooth, the other one of the assembling section and the lead screw is correspondingly provided with at least one annular groove, and the annular grooves are matched with the annular teeth in a meshed mode so that no relative axial displacement exists between the pin rollers and the lead screw. In order to overcome the defects of an existing planetary roller screw, a gear structure is omitted, burrs generated by gear machining are eliminated, the cleanliness level of a roller is improved, the influence of the burrs on thread meshing is reduced, and the overall service life is prolonged; the overall NVH level of the planetary roller screw is improved, and the machining difficulty and cost are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of planetary roller screws, and in particular to a gearless planetary roller screw. Background Art

[0002] At present, the conventional designs of the two types of planetary roller screws are both gear structures, including standard planetary roller screws and reverse planetary roller screws. In particular, the gear design on the roller is a composite design of threads and gears, that is, there are threads on the gears at both ends of the roller, as shown in the figure. Because the thread diameter of the conventional roller design is consistent with the gear pitch circle, the gear part of the roller needs to mesh with both the gear on the inner gear ring and the thread of the screw, which results in the gears at both ends of the roller needing both gears and threads, that is, there is a composite part of gears and threads.

[0003] Such a structure can ensure the normal transmission of the planetary roller screw, but there are many problems with the gear structure. For example, the gear structure is difficult to process and burrs are difficult to clean. At the same time, due to the presence of threads in the gear part, the tooth shape is incomplete, which reduces the strength of the gear and increases the noise. Similarly, due to the presence of gears on the threads at both ends, the thread part is also incomplete, which also affects the strength of the thread and generates noise.

[0004] In addition to being prone to noise, the part where the gear and thread are combined is incomplete, which is more prone to wear. Wear will affect the limiting effect on the roller, and the existence of the helix angle will make the roller more likely to tilt.

[0005] In summary, the main problems with the internal gear structure of the planetary roller screw are high processing costs; burrs are easily generated, affecting the cleanliness of the assembly, which in turn aggravates wear and affects the service life; at the same time, since the design of the gear tooth top circle is subject to the size of the major diameter of the thread, it often leads to a low overlap, which will cause impact and noise in the gear meshing. Summary of the invention

[0006] In view of the technical problems of defects in the existing planetary roller screws, the present invention provides a gearless planetary roller screw, which simplifies the structure of the roller, eliminates the roller gear, and correspondingly eliminates the gear on the screw or the inner gear ring on the nut, thereby eliminating the burrs caused by gear processing, improving the cleanliness level of the roller, reducing the influence of the burrs on the thread meshing, and improving the overall life of the planetary roller screw. At the same time, the gear meshing is eliminated, the impact and noise caused by the gear meshing are avoided, the overall NVH level of the planetary roller screw is improved, and the processing difficulty and cost are reduced as a whole. In addition, the setting of the multi-groove retainer plays a role in preventing the roller from tilting, completely replacing the role of the gears at both ends, and has a low degree of wear. Compared with gear meshing, the efficiency loss caused is lower.

[0007] The technical solution provided by the present invention is: a gearless planetary roller screw, comprising a nut, a screw and a plurality of rollers; the nut is arranged on the outside of the screw, and the plurality of rollers are evenly distributed between the screw and the nut along the circumferential direction, a multi-groove retainer is arranged between the nut and the screw, the length of the multi-groove retainer is less than or equal to the length of the nut, the multi-groove retainer is circumferentially provided with a plurality of through accommodating grooves, the rollers are located in the accommodating grooves, and the inner walls of the accommodating grooves are used to contact the rollers; an internal thread is arranged on the nut, an external thread is arranged on the outer wall of the screw, and a matching thread is arranged in the middle of the roller; the internal thread is meshed with the matching thread, and the external thread is meshed with the matching thread. The thread is meshed with the mating thread; an assembly section is provided on the roller, and the assembly section is located at both ends of the mating thread; when the screw is an active part, at least one ring tooth is provided on one of the assembly section and the nut, and at least one ring groove is correspondingly provided on the other, and the ring groove is meshed with the ring tooth so that there is no relative axial displacement between the roller and the nut; when the nut is an active part, at least one ring tooth is provided on one of the assembly section and the screw, and at least one ring groove is correspondingly provided on the other, and the ring groove is meshed with the ring tooth so that there is no relative axial displacement between the roller and the screw, and the ring teeth or ring grooves on the screw are located at both ends of the external thread.

[0008] Optionally, the multi-groove retaining frame is clearance-matched with the nut and the lead screw.

[0009] Optionally, the outer diameter of the assembly section is smaller than the outer diameter of the mating thread.

[0010] Optionally, the tooth profile of the ring tooth is consistent with the thread profile of the mating thread.

[0011] Optionally, the tooth profile of the annular groove includes a triangle or an arc shape.

[0012] Optionally, the tooth profile of the annular teeth or annular grooves includes a triangle or an arc shape.

[0013] Optionally, the length of the roller is less than or equal to the length of the nut.

[0014] The technical solution provided by the present invention has the following beneficial effects compared with the prior art: In view of the technical problems of defects in the existing planetary roller screw, the present invention simplifies the structure of the roller, eliminates the roller gear, and correspondingly eliminates the gear on the screw or the inner gear ring on the nut, thereby eliminating the burrs caused by gear processing, improving the cleanliness level of the roller, reducing the influence of the burrs on the thread meshing, and improving the overall life of the planetary roller screw. At the same time, the gear meshing is eliminated, the impact and noise caused by the gear meshing are avoided, the overall NVH level of the planetary roller screw is improved, and the processing difficulty and cost are reduced as a whole. In addition, the setting of the multi-groove retainer plays a role in preventing the roller from tilting, completely replacing the role of the gears at both ends, and has a low degree of wear. Compared with gear meshing, the efficiency loss caused is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is one of the implementations of the gearless planetary roller screw proposed in the embodiment of the present invention.

[0016] Figure 2 for Figure 1 Schematic diagram of the exploded structure of the embodiment shown.

[0017] Figure 3 This is the second implementation of the gearless planetary roller screw proposed in the embodiment of the present invention.

[0018] Figure 4 for Figure 3 Schematic diagram of the exploded structure of the embodiment shown. DETAILED DESCRIPTION

[0019] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments.

[0020] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the relevant inventions, rather than to limit the invention. It should also be noted that, for the convenience of description, only the parts related to the invention are shown in the accompanying drawings. The words "first", "second", etc. described in the present invention are set for the convenience of describing the technical solution of the present invention, and have no specific limiting effect. They are all general references and do not constitute a limiting effect on the technical solution of the present invention. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection between the insides of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Multiple technical solutions in the same embodiment, and multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions without contradictions or conflicts, all of which are within the scope of protection required by the present invention.

[0021] Example 1

[0022] Combined with Figure 1-4 This embodiment proposes a gearless planetary roller screw, comprising a nut 1, a screw 2 and a plurality of rollers 3. The nut 1 is arranged outside the screw 2, and the plurality of rollers 3 are evenly distributed between the screw 2 and the nut 1 along the circumferential direction. A multi-groove retainer 6 is arranged between the nut 1 and the screw 2, and the length of the multi-groove retainer 6 is less than or equal to the length of the nut 1. The multi-groove retainer 6 is provided with a plurality of through accommodating grooves 60 along the circumferential direction. The rollers 3 are located in the accommodating grooves 60, and the inner wall of the accommodating grooves 60 is used to contact the rollers 3.

[0023] An internal thread is provided on the nut 1, an external thread 20 is provided on the outer wall of the screw 2, and a matching thread 30 is provided in the middle of the roller 3; the internal thread is meshed with the matching thread 30, and the external thread 20 is meshed with the matching thread 30; an assembly section 31 is provided on the roller 3, and the assembly section 31 is located at both ends of the matching thread 30.

[0024] In this embodiment, the screw 2 is the active part, and at least one ring tooth 4 is provided on one of the assembly section 31 and the nut 1, and at least one ring groove 5 is correspondingly provided on the other. The ring groove 5 is meshed with the ring tooth 4 so that there is no relative axial displacement between the roller 3 and the nut 1.

[0025] The gearless planetary roller screw proposed in this embodiment is in the form of a standard planetary roller screw, that is, the screw 2 is the active component, the nut 1 is the output component, and the rotation of the screw 2 is transmitted to the nut 1 through the roller 3, forming a linear motion output of the nut 1. In order to ensure the matching effect between the nut 1 and the roller 3, generally speaking, the length of the roller 3 is less than or equal to the length of the nut 1.

[0026] In this embodiment, the structure of the roller 3 is simplified, the gear of the roller 3 is eliminated, and the structure of the nut 1 is simplified accordingly, and the inner gear ring of the nut 1 is eliminated, thereby eliminating the burrs caused by gear processing, improving the cleanliness level of the roller 3, reducing the influence of the burrs on the thread meshing, and improving the overall life of the planetary roller screw. At the same time, since the gear meshing is eliminated, the impact and noise caused by the gear meshing are avoided, and the overall NVH level of the planetary roller screw is improved. In addition, since the gear processing is eliminated, the processing difficulty and cost are greatly reduced.

[0027] At the same time, this embodiment further provides a multi-groove retainer 6 between the nut 1 and the lead screw 2. The multi-groove retainer 6 is provided with a plurality of through accommodating grooves 60 along the circumferential direction, and the roller 3 is located in the accommodating grooves 60. During the operation of the roller 3, the roller 3 may tilt due to the existence of the helix angle, and the multi-groove retainer 6 provided in this embodiment has good rigidity and can cooperate with the roller 3 to prevent the roller 3 from tilting, playing the role of a gear. In addition, in order to avoid interference and ensure the effective cooperation between the lead screw 2, the nut 1 and the roller 3, the multi-groove retainer 6 is clearance-fitted with the nut 1 and the lead screw 2.

[0028] Furthermore, in order to prevent the cooperation between the annular groove 5 and the annular tooth 4 from affecting the meshing between the matching thread 30 on the roller 3 and the nut 1 and the lead screw 2 , the outer diameter of the assembly section 31 is smaller than the outer diameter of the matching thread 30 .

[0029] In addition, in order to achieve efficient meshing between the annular groove 5 and the annular tooth 4, the tooth profile of the annular tooth 4 can be triangular or circular arc-shaped, etc., and correspondingly, the tooth profile of the annular groove 5 can also be triangular or circular arc-shaped, etc. Among them, the tooth profile of the annular tooth 4 refers to the cross-sectional shape of the annular tooth 4, and the tooth profile of the annular groove 5 refers to the cross-sectional shape of the annular groove 5. In one embodiment, the tooth profile of the annular tooth 4 or the annular groove 5 is consistent with the thread tooth profile of the mating thread 30.

[0030] It can be understood that the annular groove 5 and the annular tooth 4 are provided to replace the traditional gear meshing, and therefore the number of the annular groove 5 and the annular tooth 4 can also affect the replacement effect. Generally speaking, at least one annular groove 5 and one annular tooth 4 are provided. Obviously, within a certain range, the more annular grooves 5 and annular teeth 4 there are, the better the effect of limiting the relative axial displacement between the roller 3 and the nut 1 will be. Therefore, the number of annular grooves 5 and the annular teeth 4 can be adjusted according to actual conditions.

[0031] Example 2

[0032] Combined with Figure 3-4 This embodiment proposes a gearless planetary roller screw, comprising a nut 1, a screw 2 and a plurality of rollers 3. The nut 1 is arranged outside the screw 2, and the plurality of rollers 3 are evenly distributed between the screw 2 and the nut 1 along the circumferential direction. A multi-groove retainer 6 is arranged between the nut 1 and the screw 2, and the length of the multi-groove retainer 6 is less than or equal to the length of the nut 1. The multi-groove retainer 6 is provided with a plurality of through accommodating grooves 60 along the circumferential direction. The rollers 3 are located in the accommodating grooves 60, and the inner wall of the accommodating grooves 60 is used to contact the rollers 3.

[0033] An internal thread is provided on the nut 1, an external thread 20 is provided on the outer wall of the screw 2, and a matching thread 30 is provided in the middle of the roller 3; the internal thread is meshed with the matching thread 30, and the external thread 20 is meshed with the matching thread 30; an assembly section 31 is provided on the roller 3, and the assembly section 31 is located at both ends of the matching thread 30.

[0034] This embodiment is similar to Embodiment 1 as a whole, but the difference compared with the technical solution of Embodiment 1 is that in this embodiment, the nut 1 is an active part, and at least one ring tooth 4 is provided on one of the assembly section 31 and the screw 2, and at least one ring groove 5 is correspondingly provided on the other, and the ring groove 5 is engaged with the ring tooth 4 so that there is no relative axial displacement between the roller 3 and the screw 2, and the ring tooth 4 or the ring groove 5 on the screw 2 is located at both ends of the external thread 20.

[0035] The gearless planetary roller screw proposed in this embodiment is in the form of a reverse planetary roller screw, that is, the screw 2 is the active component, the nut 1 is the output component, and the rotation of the screw 2 is transmitted to the nut 1 through the roller 3, forming a linear motion output of the nut 1.

[0036] Similar to the aforementioned standard planetary roller screw, in the reverse planetary roller screw of this embodiment, the structure of the roller 3 is also simplified, the gear of the roller 3 is eliminated, and the structure of the screw 2 is simplified accordingly.

[0037] Compared with the traditional reverse planetary roller screw, in this embodiment, the external gear of the screw 2 is also eliminated (there is no internal gear ring on the nut 1), and the cooperation between the ring teeth 4 and the ring groove 5 ensures that there is no relative axial displacement between the roller 3 and the screw 2.

[0038] As a result, the burrs generated by gear processing are eliminated, the cleanliness level of the roller 3 is improved, the influence of the burrs on the thread meshing is reduced, and the overall life of the planetary roller screw can be improved. At the same time, since the gear meshing is eliminated, the impact and noise caused by the gear meshing are avoided, and the overall NVH level of the planetary roller screw is improved. In addition, since the gear processing is cancelled, the processing difficulty and cost are greatly reduced.

[0039] Similar to the first embodiment, in this embodiment, a multi-groove retainer 6 is also provided between the nut 1 and the lead screw 2. The multi-groove retainer 6 is provided with a plurality of through accommodating grooves 60 along the circumferential direction, and the roller 3 is located in the accommodating grooves 60. During the operation of the roller 3, the roller 3 may be tilted due to the existence of the helix angle. The multi-groove retainer 6 added in this embodiment has good rigidity and can cooperate with the roller 3 to prevent the roller 3 from tilting, playing the role of a gear. In addition, in order to avoid interference and ensure the effective cooperation between the lead screw 2, the nut 1 and the roller 3, the multi-groove retainer 6 is clearance-fitted with the nut 1 and the lead screw 2.

[0040] Furthermore, in order to prevent the cooperation between the annular groove 5 and the annular tooth 4 from affecting the meshing between the matching thread 30 on the roller 3 and the nut 1 and the lead screw 2 , the outer diameter of the assembly section 31 is smaller than the outer diameter of the matching thread 30 .

[0041] In addition, in order to achieve efficient meshing between the annular groove 5 and the annular tooth 4, the tooth profile of the annular tooth 4 can also be triangular or circular arc-shaped, etc., and correspondingly, the tooth profile of the annular groove 5 can also be triangular or circular arc-shaped, etc. In one embodiment, the tooth profile of the annular tooth 4 or the annular groove 5 is consistent with the thread tooth profile of the mating thread 30.

[0042] Furthermore, in this embodiment, at least one annular groove 5 and one annular tooth 4 are provided, and the specific number of the annular groove 5 and the annular tooth 4 can be adjusted according to actual conditions.

[0043] The present invention and its embodiments are described schematically above, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and creatively designs a structure and an embodiment similar to the technical solution without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A gearless planetary roller screw, characterized in that: It comprises a nut (1), a lead screw (2) and a plurality of rollers (3); The nut (1) is arranged on the outside of the screw (2), a plurality of rollers (3) are evenly distributed between the screw (2) and the nut (1) along the circumferential direction, a multi-groove retainer (6) is arranged between the nut (1) and the screw (2), the length of the multi-groove retainer (6) is less than or equal to the length of the nut (1), the multi-groove retainer (6) is provided with a plurality of through receiving grooves (60) along the circumferential direction, the rollers (3) are located in the receiving grooves (60), and the inner wall of the receiving groove (60) is used to contact the rollers (3); The nut (1) is provided with an internal thread, the outer wall of the lead screw (2) is provided with an external thread (20), and the middle part of the roller (3) is provided with a matching thread (30); the internal thread is meshed with the matching thread (30), and the external thread (20) is meshed with the matching thread (30); The roller (3) is provided with an assembly section (31), and the assembly section (31) is located at both ends of the matching thread (30); When the screw (2) is an active component, at least one annular tooth (4) is provided on one of the assembly section (31) and the nut (1), and at least one annular groove (5) is correspondingly provided on the other, and the annular groove (5) is meshed with the annular tooth (4) so ​​that there is no relative axial displacement between the roller (3) and the nut (1); When the nut (1) is an active component, at least one annular tooth (4) is provided on one of the assembly section (31) and the lead screw (2), and at least one annular groove (5) is correspondingly provided on the other, and the annular groove (5) is meshed with the annular tooth (4) so ​​that there is no relative axial displacement between the roller (3) and the lead screw (2), and the annular tooth (4) or the annular groove (5) on the lead screw (2) is located at both ends of the external thread (20).

2. The gearless planetary roller screw according to claim 1, characterized in that: The multi-groove retainer (6) is clearance-matched with the nut (1) and the lead screw (2).

3. The gearless planetary roller screw according to claim 1, characterized in that: The outer diameter of the assembly section (31) is smaller than the outer diameter of the matching thread (30).

4. The gearless planetary roller screw according to claim 1, characterized in that: The tooth profile of the annular tooth (4) is consistent with the thread profile of the matching thread (30).

5. A gearless planetary roller screw according to claim 1 or 4, characterized in that: The tooth profile of the annular groove (5) includes a triangle or an arc shape.

6. A gearless planetary roller screw according to claim 1 or 4, characterized in that: The tooth profile of the annular teeth (4) or the annular groove (5) includes a triangle or an arc shape.

7. The gearless planetary roller screw according to claim 1, characterized in that: The length of the roller (3) is less than or equal to the length of the nut (1).

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