Planetary roller screw mechanism

Abstract

The planetary roller lead screw mechanism comprises a lead screw, a nut assembly and a pushing assembly, the lead screw is provided with a first end and a second end which are oppositely arranged, the lead screw comprises a plurality of threaded sections and a plurality of stay sections, and the threaded sections and the stay sections are alternately arranged from the first end to the second end. The nut assembly is arranged on the outer side of the lead screw in a sleeving mode and can be meshed with the threaded section. The pushing assembly is in transmission connection with the lead screw and can be driven by the lead screw to push the nut assembly to move from the stop section to the threaded section. According to the planetary roller lead screw mechanism, movement and stop of the nut assembly on the lead screw can be achieved, meanwhile, the pushing assembly is arranged and matched with the lead screw, the nut assembly can be pushed to move from the stop section to the threaded section, and therefore it is guaranteed that movement and stop of the mounting frame alternately work; the problem that an existing planetary roller lead screw mechanism is single in movement process is solved.

Description

Technical Field

[0001] This invention relates to the field of lead screw technology, and specifically to a planetary roller lead screw mechanism. Background Technology

[0002] A lead screw is a mechanical device that can convert rotary motion into linear motion. There are two main types of commonly used high-efficiency lead screws: roller lead screws and planetary roller lead screws. The latter has two types: standard and reverse. A standard planetary roller lead screw has a long lead screw and a short nut structure, with no axial relative motion between the rollers and the nut. A reverse planetary roller lead screw has a short lead screw and a long nut structure, with no axial relative motion between the rollers and the lead screw. Because planetary roller lead screws use threaded rollers instead of traditional rollers as the force transmission unit, their force transmission unit has a larger contact radius and more contact points compared to traditional roller lead screws. Therefore, their rated load, stiffness, speed, and lifespan are all improved. However, existing planetary roller lead screws can only perform linear extension and retraction in one direction, resulting in a narrow stroke range. Summary of the Invention

[0003] The objective of this invention is to at least solve the problem of the single motion process in existing planetary roller screw mechanisms. This objective is achieved through the following technical solution: The first aspect of this invention provides a planetary roller screw mechanism, comprising: A lead screw having a first end and a second end arranged in opposite directions, the lead screw including a plurality of threaded segments and a plurality of stationary segments, the threaded segments and the stationary segments being alternately arranged from the first end to the second end; A nut assembly, which is sleeved on the outside of the lead screw and can engage with the threaded section; A pushing component is connected to the lead screw drive, and the pushing component can push the nut assembly from the dwell section to the threaded section under the drive of the lead screw. The planetary roller screw mechanism of this invention includes a screw, a nut assembly, and a pusher assembly. By setting the screw to alternate between threaded and stationary sections, and cooperating with the nut assembly mounted on the screw, the nut assembly can move and stop on the screw. Simultaneously, by setting the pusher assembly in conjunction with the screw, the nut assembly can be pushed from the stationary section to the threaded section, thus ensuring the alternating movement and stopping of the mounting bracket, helping to solve the problem of the single motion process in existing planetary roller screw mechanisms. Furthermore, the cooperative structure of the screw and nut assembly can effectively determine the stopping position of the nut assembly, thereby enabling other operations in conjunction with external structures and improving the overall performance of the planetary roller screw mechanism.

[0004] In addition, the planetary roller screw mechanism according to the present invention may also have the following additional technical features: In some embodiments of the present invention, the planetary roller screw further includes: The guide assembly includes guide posts; Mounting bracket, which is movably mounted on the guide post, and the nut assembly is mounted on the mounting bracket.

[0005] In some embodiments of the present invention, the number of guide posts is two, and the two guide posts are respectively disposed on opposite sides of the lead screw and spaced apart from the lead screw, and the mounting bracket has mounting holes adapted to the guide posts.

[0006] In some embodiments of the present invention, the nut assembly includes: The first nut is connected to the mounting bracket, and the inner wall of the first nut is provided with threads, and the first nut is fitted on the lead screw; A first support assembly is disposed inside the first nut and engages with the internal thread and the threaded segment of the first nut, respectively. The first limiting member consists of two members, which are spaced apart on the first nut and located at both ends of the first bracket assembly to restrict the axial movement of the first bracket assembly.

[0007] In some embodiments of the present invention, the first support assembly includes two first planetary carriers and a plurality of first rollers. The two first planetary carriers are spaced apart, and the first rollers are rotatably disposed between the two first planetary carriers. The outer wall of the first roller is provided with an external thread, and the external thread of the first roller engages with the internal thread of the first nut and the threaded segment.

[0008] In some embodiments of the present invention, the nut assembly further includes two internal gear rings, which are spaced apart inside the first nut and located at opposite ends of the first nut, and the first planetary carrier is fixed to the internal gear rings.

[0009] In some embodiments of the present invention, a first gear is provided at the first end of the lead screw, and the pushing assembly includes: The second nut has a first meshing part on its outer wall, and the first meshing part meshes with the first gear. A push rod is disposed inside the second nut, and one end of the push rod is provided with an external toothed thread sleeve; The second bracket assembly is fitted onto the outside of the external toothed threaded sleeve; The second limiting member, there are two of them, and the two second limiting members are spaced apart on the push rod and located at both ends of the second bracket assembly, so as to limit the axial movement of the second bracket assembly.

[0010] In some embodiments of the present invention, the second support assembly includes two second planetary carriers and a plurality of second rollers, the second planetary carriers being spaced apart on both sides of the second rollers, the outer wall of the second rollers being threaded, and the outer wall of the second rollers engaging with the inner wall of the second nut and the outer wall of the external toothed threaded sleeve.

[0011] In some embodiments of the present invention, the nut assembly engages with the threaded segment and has a first speed, and the push rod of the push assembly has a second speed, wherein the first speed is 1.5-3 times the second speed.

[0012] In some embodiments of the present invention, the planetary roller screw further includes a drive motor, the output end of which is connected to the first end. Attached Figure Description

[0013] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of the planetary roller screw mechanism shown in an embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of the planetary roller screw mechanism shown from another perspective; Figure 3 for Figure 1 A schematic cross-sectional view of the planetary roller screw mechanism shown in the first section; Figure 4 for Figure 3 A magnified schematic diagram of a portion of the structure of A shown; Figure 5 for Figure 3 The diagram shows an enlarged view of a portion of the structure of B.

[0014] The markings in the attached diagram are as follows: 100. Planetary roller screw mechanism; 10. Lead screw; 101. First end; 102. Second end; 11. Threaded section; 12. Dwell section; 20. Nut assembly; 21. First nut; 22. First support assembly; 221. First planetary carrier; 222. First roller; 30. Drive the components; 31. Second nut; 311. First fixing hole; 32. Push rod; 321. External threaded sleeve; 33. Second support assembly; 331. Second planetary carrier; 332. Second roller; 34. Internal gear ring; 40. Guide assembly; 41. Guide post; 50. Mounting bracket; 51. Mounting hole; 52. Second fixing hole; 60. Drive motor; 70. The first gear; 80. First meshing part. Detailed Implementation

[0015] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0016] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also mean including the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0017] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0018] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations.

[0019] A lead screw is a mechanical device that can convert rotary motion into linear motion. There are two main types of commonly used high-efficiency lead screws: roller lead screws and planetary roller lead screws. The latter mainly consists of a lead screw, rollers, and a nut. Because it uses threaded rollers instead of rollers as the force transmission unit, its force transmission unit has a larger contact radius and more contact points compared to roller lead screws. Therefore, its rated load, stiffness, speed, and service life are all improved. However, existing planetary roller lead screws can only perform linear motion in one direction, and the stroke range is narrow.

[0020] To solve the above problems, such as Figures 1-5 As shown, this invention proposes a planetary roller screw mechanism 100. The overall design of the planetary roller screw mechanism 100 includes a screw, a nut assembly 20, and a push assembly 30. The screw has a first end 101 and a second end 102 arranged opposite to each other. The screw includes multiple threaded sections 11 and multiple stationary sections 12, with the threaded sections 11 and stationary sections 12 alternating from the first end 101 to the second end 102. The nut assembly 20 is sleeved on the outside of the screw and can engage with the threaded sections 11. The push assembly 30 is drively connected to the screw 10, and under the drive of the screw 10, the push assembly 30 can push the nut assembly 20 from the stationary section 12 to the threaded section 11.

[0021] Specifically, by setting the lead screw 10 to alternate between a threaded section 11 and a dwell section 12, and cooperating with the nut assembly 20 mounted on the lead screw 10, the nut assembly 20 can move and stay on the lead screw 10. Simultaneously, by setting a push assembly 30 in conjunction with the lead screw 10, the nut assembly 20 can be pushed from the dwell section 12 to the threaded section 11, thus ensuring the alternating movement and dwell of the mounting bracket 50. This helps solve the problem of the single motion process in existing planetary roller screw mechanisms 100. Furthermore, by utilizing the cooperation structure between the lead screw 10 and the nut assembly 20, the stopping position of the nut assembly 20 can be effectively determined, thereby enabling other operations in conjunction with external structures and improving the performance of the planetary roller screw mechanism 100.

[0022] It is necessary to understand that, such as Figures 1 to 3 As shown, the lead screw 10 has a first end 101 and a second end 102 arranged in opposite directions. The lead screw 10 includes multiple threaded sections 11 and multiple stationary sections 12, with the threaded sections 11 and stationary sections 12 alternately arranged along the axial direction of the lead screw 10. Optionally, both the first end 101 and the second end 102 of the lead screw 10 are provided with threaded sections 11. Meanwhile, the nut assembly 20 is sleeved on the outside of the lead screw and can engage with the threaded sections 11. In this case, the nut assembly 20 is engaged with the threaded sections 11 and can move along the axial direction of the lead screw 10 when the lead screw 10 rotates; that is, the nut assembly 20 can move from the threaded section 11 to the stationary section 12 when the lead screw 10 rotates. Connecting the nut assembly 20 and the lead screw 10 by screwing ensures the accuracy and stability of the movement of the nut assembly 20.

[0023] Still Figures 1 to 3 As shown, the drive assembly 30 is connected to the lead screw 10. When the lead screw 10 rotates, the nut assembly 20 can move from the threaded section 11 to the dwell section 12. At the same time, the drive assembly 30 works under the drive of the lead screw 10, pushing the nut assembly 20 from the dwell section 12 to the threaded section 11. This configuration ensures that the nut assembly 20 moves from the dwell section 12 to the threaded section 11 and engages with the threaded section 11; on the other hand, it also allows for control of the dwell time of the nut assembly 20 in conjunction with the rotation of the lead screw 10.

[0024] It should be noted that, along the axial direction of the lead screw 10, the length of the dwelling section 12 is at least greater than the internal thread length of the second nut 31, and the length of the threaded section 11 is greater than or equal to the length of the dwelling section 12. In this embodiment, along the axial direction of the lead screw 10, the length of the dwelling section 12 and the length of the threaded section 11 are the same.

[0025] Furthermore, the planetary roller screw mechanism 100 also includes a guide assembly 40 and a mounting bracket 50, wherein the guide assembly 40 includes a guide post 41, the mounting bracket 50 is movably disposed on the guide post 41, and the nut assembly 20 is disposed on the mounting bracket 50.

[0026] Specifically, by setting the guide post 41, the stability of the movement of the mounting bracket 50 can be effectively achieved, which in turn can ensure the stability of the movement of the nut assembly 20 on the lead screw 10. At the same time, it can effectively ensure that the nut assembly 20 will not wobble when it moves from the threaded section 11 to the stationary section 12, thereby ensuring the stability of the nut assembly 20.

[0027] Understandably, the guide component 40 can be configured as a guide rail, and the mounting bracket 50 is provided with a guide groove adapted to the guide rail. In this case, the guide rail can be set on the ground or a foundation mounting surface. Optionally, the guide rail can be configured as a "T" shaped structure or other irregular shapes. This configuration helps ensure the effective cooperation between the guide component 40 and the mounting bracket 50. The guide component 40 can also be configured as a columnar guide member, and the mounting bracket 50 is provided with a limiting structure adapted to the guide member. In this case, the columnar guide member can be mounted on a foundation mounting member, thereby achieving a suspended configuration of the mounting bracket 50.

[0028] In this embodiment, the guide assembly 40 includes guide posts 41. Optionally, there are two guide posts 41, which are respectively arranged on opposite sides of the lead screw 10 and spaced apart from it. The mounting bracket 50 has mounting holes 51 that mate with the guide posts 41. This arrangement helps ensure the stability of the mounting bracket 50 on the guide assembly 40, preventing the guide assembly 40 from shaking. Of course, in addition, the number of guide posts 41 can also be three, four, etc., arranged around the lead screw 10 as the center, thereby ensuring the stability of the guide assembly 40.

[0029] Furthermore, the nut assembly 20 includes a first nut 21, a first bracket assembly 22, and first limiting members. The first nut 21 is connected and disposed on the mounting bracket 50, and the inner wall of the first nut 21 is threaded, and the first nut 21 is fitted onto the lead screw. The first bracket assembly 22 is disposed inside the nut. There are two first limiting members, which are spaced apart on the first nut 21 and located at both ends of the first bracket assembly 22 to limit the axial movement of the first bracket assembly 22.

[0030] Specifically, by configuring the nut assembly 20 as a first nut 21, a first bracket assembly 22, and a first limiting member, it can be formed as a whole, thereby facilitating the transmission connection between the nut assembly 20 and the lead screw 10.

[0031] It is necessary to understand that, such as Figure 3 and Figure 4 As shown, the first nut 21 is connected to the mounting bracket 50. Optionally, the mounting bracket 50 is provided with a second fixing hole 52. The first nut 21 also has an extension structure with a first fixing hole 311. The first nut 21 is connected to the mounting bracket 50 by a fastener. The fastener is a screw or bolt, which passes through the second fixing hole 52 and is screwed into the first fixing hole 311. Furthermore, the inner wall of the first nut 21 is threaded, meaning the first nut 21 has internal threads.

[0032] like Figure 3 As shown, the first support assembly 22 is disposed inside the first nut 21. Simultaneously, first limiting members (not shown in the figure) are respectively provided at both ends of the first support assembly 22. Optionally, the two first limiting members are spaced apart on the first nut 21 to restrict the axial movement of the first support assembly 22. It is understood that the first limiting members may be disposed on the first nut 21 and at least partially extend into the interior of the first nut 21, abutting against one side of the first support assembly 22, thereby limiting the movement of the first support assembly 22. Optionally, the first limiting members may be fasteners such as bolts or pins.

[0033] Furthermore, the first support assembly 22 includes two first planetary carriers 221 and a plurality of first rollers 222. The two first planetary carriers 221 are spaced apart, and the first rollers 222 are rotatably disposed between the two first planetary carriers 221. The outer wall of the first rollers 222 is provided with external threads, and the external threads of the first rollers 222 respectively mesh with the internal threads and threaded section 11 of the first nut 21.

[0034] Specifically, by setting two first planetary carriers 221 and multiple first rollers 222 to form a whole, they respectively mesh with the internal thread of the first nut 21 and the threaded section 11 of the lead screw, thereby helping to realize the transmission connection between the lead screw 10 and the first nut 21, so that the first nut 21 can move on the lead screw 10.

[0035] It should be understood that the first support assembly 22 includes two first planetary carriers 221, each with connecting holes, and spaced apart along the axis of the lead screw 10. The two ends of the first roller 222 are respectively inserted into the connecting holes of the two first planetary carriers 221, allowing the first roller 222 to be rotatably positioned between the two first planetary carriers 221. Simultaneously, the outer wall of the first roller 222 is provided with external threads, which mesh with the internal threads and threaded section 11 of the first nut 21. This arrangement forms the planetary roller lead screw mechanism 100, thereby driving the first nut 21 to move axially along the lead screw 10.

[0036] It should be noted that the specific structure of the first support assembly 22 can refer to the existing planetary roller screw 10 mechanism, and this application does not impose any restrictions on it.

[0037] It should be further understood that the nut assembly 20 also includes two internal gear rings 34, which are spaced apart inside the first nut 21 and located at opposite ends of the first nut 21. The first planetary carrier 221 is fixed to the internal gear rings 34. Specifically, the internal gear rings 34 are fixed at intervals inside the first nut 21 by fasteners. Optionally, the fasteners can be bolts, pins, or other fixing components. Figure 4 As shown, the inner wall of the internal gear ring 34 is provided with a first gear 70 structure. The side of the internal gear ring 34 opposite to the first roller 222 has a mounting groove. The first planetary carrier 221 is located inside the mounting groove and fixed to the internal gear ring 34 by a first limiting member. Optionally, the internal gear ring 34 is fixed to both ends of the first nut 21 by fasteners. In this case, both ends of the first roller 222 are provided with second gear structures, which mesh with the first gear 70 structure. The first roller 222 rotates within the first nut 21 and revolves around the lead screw. When the lead screw rotates, the first nut 21 moves linearly.

[0038] Furthermore, the first end 101 of the lead screw is provided with a first gear 70, and the push assembly 30 includes a second nut 31, a push rod 32, a second support assembly 33, and a second limiting member. The outer wall of the second nut 31 is provided with a first meshing part 80, which meshes with the first gear 70. The push rod 32 is located inside the second nut 31, and one end of the push rod 32 is provided with an external toothed thread sleeve 321. The second support assembly 33 is fitted on the outside of the external toothed thread sleeve 321. There are two second limiting members, and the two second limiting members are spaced apart on the push rod 32 and located at both ends of the second support assembly 33 to limit the axial movement of the second support assembly 33.

[0039] Specifically, by setting the second nut 31, push rod 32, second bracket assembly 33, and second limiting member to form a whole, it is easier to achieve linkage. At the same time, the first gear 70 is engaged with the first meshing part 80 so that when the lead screw 10 rotates, it drives the second nut 31 to rotate, which in turn drives the push rod 32 to move inside the second nut 31, thereby pushing the push rod 32 against the first nut 21.

[0040] It should be understood that the second nut 31 has a cylindrical tubular structure and is mounted on a base mounting structure via bearings, allowing it to rotate. Simultaneously, the outer wall of the second nut 31 is provided with a first engaging portion 80, which meshes with the first gear 70 at the first end 101 of the lead screw 10. When the lead screw 10 rotates, the second nut 31 rotates on its own axis. Figure 3 and Figure 5 As shown, the push rod 32 is located inside the second nut 31, and one end of the push rod 32 is provided with an external toothed thread sleeve 321. Along the axial direction of the push rod 32, the other end of the push rod 32 can abut against the mounting bracket 50.

[0041] In this embodiment, the second support assembly 33 is fitted onto the outside of the external threaded sleeve 321 and screwed to both the external threaded sleeve 321 and the inner wall of the second nut 31. Simultaneously, two second limiting members are spaced apart on the push rod 32 and located at opposite ends of the second support assembly 33 to restrict the axial movement of the second support assembly 33 on the push rod 32. With this configuration, the push rod 32 is connected to the second nut 31 via the second support assembly 33, enabling the push rod 32 to move linearly when the nut rotates. This pushes the mounting bracket 50 from the threaded section 11 to the stationary section 12, achieving continuous movement of the second nut 31 on the screw 10.

[0042] It needs to be further understood that the second support assembly 33 includes two second planetary carriers 331 and a plurality of second rollers 332. The second planetary carriers 331 are spaced apart on both sides of the second rollers 332. The outer wall of the second rollers 332 is provided with threads, and the outer wall of the second rollers 332 meshes with the inner wall of the second nut 31 and the outer wall of the external toothed thread sleeve 321.

[0043] Two second planetary carriers 331 are provided with mounting holes and are spaced apart along the axis of the push rod 32. The two ends of the second roller 332 are respectively inserted into the mounting holes of the two second planetary carriers 331, so that the first roller 222 is rotatably disposed between the two second planetary carriers 331. At the same time, the outer wall of the second roller 332 is provided with threads, and the external threads of the second roller 332 mesh with the internal threads of the second nut 31 and the outer wall of the external toothed sleeve 321, respectively. This arrangement can form a reversible planetary roller screw mechanism, thereby driving the push rod 32 to move inside the second nut 31.

[0044] Furthermore, the nut assembly 20 engages with the threaded section 11 and has a first speed, while the push rod 32 of the pushing assembly 30 has a second speed, with the first speed being 1.5 to 3 times the second speed.

[0045] Specifically, by giving the nut assembly 20 a first speed on the lead screw 10 and the push rod 32 a second speed, with the first speed being 1.5 to 3 times the second speed, it is possible to achieve different speeds for the mounting bracket 50 and the push rod 32, thereby helping to control the dwell time of the mounting bracket 50 on the lead screw 10 and improving the performance of the planetary roller lead screw mechanism 100.

[0046] It is necessary to understand that, such as Figures 1 to 3As shown, when the lead screw 10 rotates, the nut assembly 20 meshes with the threaded section 11 and has a first speed, while the second nut 31 engages with the first meshing part 80, causing the push rod 32 to have a second speed. Optionally, by controlling the dimensions of the first gear 70, the push assembly 30, the nut assembly 20, etc., it is helpful to control the percentage of the first speed and the second speed, thereby determining the effectiveness of the planetary roller screw mechanism 100.

[0047] like Figures 1 to 3 As shown, the planetary roller screw mechanism 100 also includes a drive motor 60, the output end of which is connected to the first end 101. Specifically, the drive motor 60 has a rotatable output shaft, which is fixedly connected to the first end 101 of the screw 10 via a connecting sleeve. When the drive motor 60 is working, it can effectively drive the screw 10 to rotate. The connection method between the drive motor 60 and the screw 10 can refer to the existing screw 10 mounting structure; this application does not impose any restrictions on this.

[0048] Furthermore, the output shaft of the drive motor 60 can rotate alternately. A second gear is provided at the second end 102 of the lead screw. The planetary roller screw mechanism 100 also includes a third nut, a reset rod, a third support assembly, and a third limiting member. The outer wall of the third nut has a second meshing portion, which can selectively mesh with the second gear. The reset rod is located inside the third nut, and one end of the reset rod has an external toothed threaded sleeve 321. The third support assembly is fitted onto the outside of the external toothed threaded sleeve 321. There are two third limiting members, spaced apart on the reset rod and located at both ends of the third support assembly, to limit the axial movement of the third support assembly. With this configuration, the third nut, reset rod, third support assembly, and third limiting member cooperate to form a reversible planetary roller screw mechanism. This reversible planetary roller screw mechanism has the same structure as the aforementioned push assembly 30, which is not shown in the figures. This application does not impose any limitations on it.

[0049] When the drive motor 60 is working, the lead screw 10 rotates clockwise or counterclockwise. Since the first gear 70 is engaged with the first meshing part 80, the first nut 21 can move from the threaded section 11 to the stationary section 12. In conjunction with the push rod 32, the first nut 21 can move from the stationary section 12 to the threaded section 11, thus moving from the first end 101 to the second end 102. Correspondingly, when the lead screw 10 rotates counterclockwise or clockwise, the second gear is engaged with the second meshing part. In conjunction with the reset rod, the first nut 21 can move from the stationary section 12 to the threaded section 11, thus moving from the second end 102 to the first end 101.

[0050] It should be noted that in some embodiments of this application, two push plates are spaced apart at the end of the push rod 32 away from the external threaded sleeve 321, and the distance between the two push plates is greater than the length of the dwell section 12. The push plate closer to the external threaded sleeve 321 is used to drive the first nut 21 from the first end 101 to the second end 102, and the push plate farther away from the external threaded sleeve 321 is used to drive the first nut 21 from the second end 102 to the first end 101. This arrangement helps to ensure the movement and dwell of the first nut 21, thereby realizing its reciprocating motion along the axial direction of the push rod 32.

[0051] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A planetary roller screw mechanism, characterized in that, include: A lead screw having a first end and a second end arranged in opposite directions, the lead screw including a plurality of threaded segments and a plurality of stationary segments, the threaded segments and the stationary segments being alternately arranged from the first end to the second end; A nut assembly, which is sleeved on the outside of the lead screw and can engage with the threaded section; A pushing component is connected to the lead screw drive, and the pushing component can push the nut assembly from the dwell section to the threaded section under the drive of the lead screw.

2. The planetary roller screw mechanism according to claim 1, characterized in that, The planetary roller screw mechanism also includes: The guide assembly includes guide posts; Mounting bracket, which is movably mounted on the guide post, and the nut assembly is mounted on the mounting bracket.

3. The planetary roller screw mechanism according to claim 2, characterized in that, The number of guide posts is two, and the two guide posts are respectively arranged on opposite sides of the lead screw and spaced apart from the lead screw. The mounting bracket has mounting holes adapted to the guide posts.

4. The planetary roller screw mechanism according to claim 2, characterized in that, The nut assembly includes: The first nut is connected to the mounting bracket, and the inner wall of the first nut is provided with threads, and the first nut is fitted on the lead screw; A first support assembly is disposed inside the first nut and engages with the internal thread and the threaded segment of the first nut, respectively. The first limiting member consists of two members, which are spaced apart on the first nut and located at both ends of the first bracket assembly to restrict the axial movement of the first bracket assembly.

5. The planetary roller screw mechanism according to claim 4, characterized in that, The first support assembly includes two first planetary carriers and a plurality of first rollers. The two first planetary carriers are spaced apart, and the first rollers are rotatably disposed between the two first planetary carriers. The outer wall of the first roller is provided with external threads, and the external threads of the first rollers engage with the internal threads of the first nut and the threaded section.

6. The planetary roller screw mechanism according to claim 5, characterized in that, The nut assembly also includes two internal gear rings, which are spaced apart inside the first nut and located at opposite ends of the first nut, and the first planetary carrier is fixed to the internal gear rings.

7. The planetary roller screw mechanism according to claim 1, characterized in that, The first end of the lead screw is provided with a first gear, and the driving assembly includes: The second nut has a first meshing part on its outer wall, and the first meshing part meshes with the first gear. A push rod is disposed inside the second nut, and one end of the push rod is provided with an external toothed thread sleeve; The second bracket assembly is fitted onto the outside of the external toothed threaded sleeve; The second limiting member, there are two of them, and the two second limiting members are spaced apart on the push rod and located at both ends of the second bracket assembly, so as to limit the axial movement of the second bracket assembly.

8. The planetary roller screw mechanism according to claim 7, characterized in that, The second support assembly includes two second planetary carriers and a plurality of second rollers. The second planetary carriers are spaced apart on both sides of the second rollers. The outer wall of the second roller is provided with threads, and the outer wall of the second roller meshes with the inner wall of the second nut and the outer wall of the external toothed threaded sleeve.

9. The planetary roller screw mechanism according to claim 8, characterized in that, The nut assembly engages with the threaded section and has a first speed, while the push rod of the push assembly has a second speed, wherein the first speed is 1.2-3 times the second speed.

10. The planetary roller screw mechanism according to any one of claims 1-9, characterized in that, The planetary roller screw mechanism also includes a drive motor, the output end of which is connected to the first end.

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