Planetary roller screw assembly and method

Abstract

The embodiment of the application provides a planetary roller screw assembly device and method, which comprises a fixed column with a hollow structure, a threaded hole is formed in the top surface, and an opening matched with the number and position of a roller to be installed is formed in the side surface; a driving rod comprising a threaded rod and a tapered rod, the threaded rod is connected with the threaded hole, the tapered rod is located in the fixed column, and the diameter of the tapered rod gradually decreases from bottom to top; a pushing block slidingly arranged at each opening can reciprocate in the radial direction of the fixed column, the side surface close to the driving rod is a tapered surface matched with the tapered rod, the side surface away from the driving rod is provided with a thread, and the pushing block can synchronously move away from the driving rod under the action of upward movement of the tapered rod. The application can avoid extrusion of the thread tooth top on the roller and the thread tooth top on the nut, so that the planetary roller screw is prevented from being damaged in the installation process.

Description

Technical Field

[0001] The embodiments of this application relate to the field of parts assembly technology, and in particular to a planetary roller screw assembly device and method. Background Technology

[0002] When assembling a planetary roller screw, the rollers need to be pushed to the inner side of the nut for fixed installation. Since both the rollers and the inner side of the nut have threads, the assembly of the planetary roller screw only restricts the horizontal movement of the rollers when they are pushed to the inner side of the nut, without completely limiting the vertical movement. During the process of pushing the rollers, the roller threads may partially engage with the nut threads. Radial thrust can cause the roller threads to fully engage, resulting in the rollers potentially shifting vertically. This may cause the thread crests on the rollers and the thread crests on the nut to be squeezed, thereby damaging the threads on the rollers and / or the nut, and consequently damaging the planetary roller screw. Summary of the Invention

[0003] To avoid damage to planetary roller screws during the assembly process, embodiments of this application provide a planetary roller screw assembly device and method.

[0004] In a first aspect of this application, a planetary roller screw assembly device is provided, comprising:

[0005] The internal structure of the fixed column is hollow, with threaded holes on the top surface and openings on the side that match the number and position of the rollers to be installed;

[0006] A drive rod includes a threaded rod and a tapered rod, the threaded rod being connected to the threaded hole, and the tapered rod being located inside the fixed column with its diameter gradually decreasing from bottom to top;

[0007] The push block, which is slidably disposed at each of the openings, can slide back and forth along the radial direction of the fixed column. The side near the drive rod is a conical surface adapted to the tapered rod, and the side away from the drive rod has threads. The push block can move synchronously away from the drive rod under the upward movement of the tapered rod.

[0008] In one possible implementation, the threaded side of the push block is an inwardly recessed semi-cylindrical surface.

[0009] In one possible implementation, a groove is formed on the semi-cylindrical surface, and a telescopic spring is disposed in the groove.

[0010] In one possible implementation, the fixing post, the threaded hole, and the drive rod are coaxial.

[0011] In one possible implementation, the threaded rod is connected to a handle on the outer portion of the fixed post.

[0012] In one possible implementation, a lower base detachably connected to the fixed post is also included, the lower base including a mounting surface having an annular limiting protrusion.

[0013] In one possible implementation, the mounting surface has the same number of positioning posts as the rollers to be installed, and the positioning posts are evenly distributed around the circumference of the fixing posts and at a preset distance from the annular limiting protrusion.

[0014] In one possible implementation, the lower base further includes a support column fixedly connected to the mounting surface. The support column is fitted with a drive nut and a support ring from bottom to top. The mounting surface has at least two through holes. The support ring has a support rod that matches the number and position of the through holes. The diameter of the support rod is less than or equal to the diameter of the through holes.

[0015] In one possible implementation, at least two of the through holes are evenly distributed along the circumferential direction of the fixing post.

[0016] In a second aspect of this application, a method for assembling a planetary roller screw is provided, applied to a planetary roller screw assembly device as described in any of the first aspects, the method comprising:

[0017] Place the roller to be installed on the corresponding push block, so that the threads on the roller to be installed and the threads on the push block are engaged.

[0018] Rotate the threaded rod to make the tapered rod move upward. Under the action of the tapered rod, the push block pushes the roller to be installed outward, so that the threads of the roller to be installed and the threads of the nut are engaged after the roller to be installed and the nut are assembled.

[0019] In the planetary roller screw assembly device and method provided in this application embodiment, the rotation of the threaded rod drives the tapered rod to move upward. Under the action of the tapered rod, the push block moves outward along the radial direction of the fixed column, thereby pushing the roller to be installed to the nut for installation and fixation. Since the surface of the push block in contact with the roller to be installed has threads, the engagement between the threads on the push block and the threads on the roller to be installed allows for vertical positioning of the roller to be installed during the pushing process, thereby avoiding the extrusion of the thread crests on the roller and the thread crests on the nut, and thus avoiding damage to the planetary roller screw.

[0020] It should be understood that the description in the Summary Section is not intended to limit the key or essential features of the embodiments of this application, nor is it intended to restrict the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0021] The above and other features, advantages, and aspects of the embodiments of this application will become more apparent from the accompanying drawings and the following detailed description. In the drawings, the same or similar reference numerals denote the same or similar elements, wherein:

[0022] Figure 1 A structural diagram of a planetary roller screw according to an embodiment of this application is shown;

[0023] Figure 2 A structural diagram of a planetary roller screw assembly device according to an embodiment of this application is shown;

[0024] Figure 3 A top view of a push block according to an embodiment of this application is shown;

[0025] Figure 4 A top view of the lower base according to an embodiment of this application is shown;

[0026] Figure 5 A flowchart illustrating a planetary roller screw assembly method according to an embodiment of this application is shown.

[0027] in,

[0028] 11. Lead screw; 12. Upper roller cage; 13. Roller; 14. Lower roller cage; 15. Nut;

[0029] 21. Handle; 22. Drive rod; 23. Fixed column; 24. Snap ring; 25. Push block connecting pin; 26. Telescopic spring; 27. Push block; 28. Base connecting pin; 29. ​​Lower base; 30. Support ring; 31. Drive nut; 32. Support platform. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0031] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms “a,” “said,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0032] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0033] It should be understood that although the terms "first," "second," etc., may be used in the embodiments of this application, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, "first" may also be referred to as "second" without departing from the scope of the embodiments of this application, and similarly, "second" may also be referred to as "first."

[0034] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0035] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0036] It should be noted that any symbols and / or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals.

[0037] To facilitate understanding of the embodiments of this application, the planetary roller screw involved in the embodiments of this application will first be introduced.

[0038] Figure 1 A structural diagram of a planetary roller screw according to an embodiment of this application is shown. See also Figure 1 The planetary roller screw includes a screw 11, multiple rollers 13, an upper roller cage 12, a lower roller cage 14, and a nut 15.

[0039] The lead screw 11 has multiple rollers 13 evenly distributed around its circumference. Nuts 15 are fitted on the outer side of the rollers 13. The threads on the lead screw 11 and the threads on the rollers 13 are engaged. The threads on the rollers 13 and the threads on the inner side of the nut are engaged. The upper roller retainer 12 and the lower roller retainer 14 are connected to the nut 15 respectively. The upper roller retainer 12 and the lower roller retainer 14 are used to limit the position of the rollers 13.

[0040] When assembling the planetary roller screw, the roller 13 needs to be pushed outward from the center of the nut 15 until the threads of the roller 13 and the inner threads of the nut 15 are engaged. Then, the roller 13 is fixed with the upper roller retainer 12 and the lower roller retainer 14.

[0041] In related technologies, since the rollers and the inner surface of the nut are both threaded, when assembling a planetary roller screw, only the horizontal movement direction of the rollers when they are pushed to the inner surface of the nut is restricted, without complete restriction in the vertical direction. During the process of pushing the rollers, the roller threads may partially engage with the nut threads, and the radial thrust may cause the roller threads to fully engage, resulting in the rollers potentially shifting in the vertical direction. This may cause the thread crests on the rollers and the thread crests on the nut to be squeezed, thereby damaging the threads on the rollers and / or the nut, and consequently damaging the planetary roller screw.

[0042] To address the aforementioned technical problems, this application provides a planetary roller screw assembly device to prevent damage to the planetary roller screw caused by damage to the threads on the rollers and / or nuts during the assembly process.

[0043] Figure 2 A structural diagram of a planetary roller screw assembly device according to an embodiment of this application is shown. See also Figure 2 The planetary roller screw assembly includes a fixed column 23, a drive rod 22, and multiple push blocks 27.

[0044] The fixing column 23 has a hollow structure inside. The top surface of the fixing column 23 has a threaded hole, and the side surface has an opening that matches the number and position of the rollers 13 to be installed.

[0045] For example, if there are 4 rollers 13 to be installed and they are evenly distributed on the inner surface of the nut 15 after installation, then 4 openings are provided on the side of the fixing post 23 and the 4 openings are evenly distributed on the side of the fixing post 23.

[0046] It should be noted that the opening penetrates the side wall of the fixing column 23, connecting the hollow space inside the fixing column 23 with the outside. The shape of the opening can be set according to the shape of the pushing block 27, and this embodiment does not impose any restrictions.

[0047] The drive rod 22 includes a threaded rod and a tapered rod. The threaded rod is connected to a threaded hole on the top surface of the fixed column 23 (e.g., a threaded connection). The tapered rod is located inside the fixed column and its diameter gradually decreases from bottom to top.

[0048] For example, the threaded rod and the tapered rod can be fixedly connected or integrally formed.

[0049] In some embodiments, the fixing post 23, the threaded hole, and the drive rod 22 are coaxial.

[0050] In this embodiment, since the threaded rod and the threaded hole on the top surface of the fixed column 23 are connected, the tapered rod can move upward or downward when the threaded rod is rotated.

[0051] The number of push blocks 27 is the same as the number of openings on the fixed post 23. Each push block 27 is correspondingly slidably disposed at the opening so that the push block 27 can slide back and forth in the fixed radial direction, and the push block 27 can move synchronously away from the drive rod 22 under the action of the upward movement of the tapered rod.

[0052] For example, multiple push blocks 27 are at the same height relative to the bottom of the fixed post 23.

[0053] For example, the cross section of the push block 27 in the axial direction of the fixed column 23 can be rectangular, and correspondingly, the shape of the opening is also rectangular.

[0054] For example, the cross-section of the push block 27 in the axial direction of the fixed post 23 can be circular, and correspondingly, the shape of the opening is also circular.

[0055] For example, a push block connecting pin 25 is slidably provided on the push block 27, which can be fixedly connected to the opening on the side of the fixing post 23.

[0056] In this embodiment of the application, in order to make the pushing blocks 27 move synchronously away from the driving rod 22 under the action of the tapered rod moving upward, the side of each pushing block 27 near the driving rod 22 can be set as a tapered surface that is adapted to the tapered rod. In this way, the tapered rod can drive multiple pushing blocks 27 to move synchronously away from the driving rod 22.

[0057] For example, the sliding distance of the push block 27 can be adjusted by setting the length of the tapered rod and the taper of the tapered surface. For instance, the longer the tapered rod, the farther the push block 27 slides; the greater the taper of the tapered surface, the farther the push block 27 slides. However, the maximum sliding distance of the push block 27 is determined by its length. Those skilled in the art can set the length of the push block 27, the length of the tapered rod, and the taper of the tapered surface according to actual needs; this embodiment does not limit the specific settings.

[0058] For example, the length of the tapered rod can be less than or equal to the distance from the lower surface of the push block 27 to the lower end of the fixed post 23.

[0059] In this embodiment, the pushing block 27 has threads on the side away from the drive rod 22, see further. Figure 2When assembling a planetary roller screw, the nut 15 can be fitted onto the fixed post 23, and the roller 13 to be installed can be placed at the corresponding push block 27. By rotating the threaded rod, the tapered rod is driven to move upward, thereby driving multiple push blocks 27 to push the roller 13 to be installed towards the inner wall of the nut. In this process, since the outer surface of the roller 13 to be installed has threads, and the side of the push block 27 that contacts the roller 13 to be installed also has threads, the roller 13 to be installed can be limited in the vertical direction through the meshing connection of the two types of threads.

[0060] In this embodiment, the rotation of the threaded rod drives the tapered rod to move upward. Under the action of the tapered rod, the push block moves outward along the radial direction of the fixed column, thereby pushing the roller to be installed to the nut for installation and fixation. Since the surface of the push block in contact with the roller to be installed has threads, the engagement between the threads on the push block and the threads on the roller to be installed allows for vertical positioning of the roller during the pushing process, thereby preventing the thread crests on the roller and the thread crests on the nut from being squeezed, thus avoiding damage to the planetary roller screw.

[0061] Furthermore, to prevent the roller to be installed from shifting horizontally during the process of the pusher block 27 pushing the roller to be installed 13, the threaded side of the pusher block 27 can be set as an inwardly concave semi-cylindrical surface (e.g., Figure 3 (As shown). Of course, the threaded side of the push block 27 can also be set to other shapes, as long as it is roughly concave to prevent the roller to be installed from shifting.

[0062] Furthermore, after pushing the roller 13 to be installed to the designated position (e.g., the installation position), the drive rod 22 and the push block 27 need to be reset for the next use. It is understood that resetting the drive rod 22 can be achieved simply by rotating the threaded rod in the opposite direction. To facilitate the reset of the push block 27, a groove can be made on the semi-cylindrical surface of the push block 27, and a telescopic spring 26 can be installed within the groove.

[0063] Specifically, the length of the telescopic spring 26 can be greater than the depth of the groove. When the push block 27 pushes the roller 13 to be installed, the telescopic spring 26 is compressed. When the drive rod 22 is reset, the push block 27 can be reset under the action of the telescopic spring 26.

[0064] Furthermore, to facilitate the rotation of the threaded rod, a handle 21 can be provided on the portion of the threaded rod located outside the fixed post 23.

[0065] See also Figure 2The planetary roller screw assembly also includes a lower base 29, which includes a mounting surface and a support column. For example, the support column and the mounting surface can be fixedly connected or integrally formed.

[0066] The fixing post 23 and the mounting surface are detachably connected. For example, the fixing post 23 and the mounting surface can be connected via a base connecting pin 28; for instance, the lower end of the fixing post 23 can be connected to the mounting surface via the base connecting pin 28. For example, the fixing post 23 and the mounting surface are coaxially arranged.

[0067] See Figure 4 The mounting surface has an annular limiting protrusion. The annular limiting protrusion is used to secure the nut 15 in the planetary roller screw. For example, the diameter of the annular limiting protrusion can be determined according to the outer diameter of the nut 15. By setting the diameter of the annular limiting protrusion, the nut 15 can be placed coaxially with the fixing post 12 when it is placed on the mounting surface.

[0068] Furthermore, the mounting surface also has the same number of positioning pins as the rollers 13 to be installed. These positioning pins are evenly distributed along the circumference of the fixing point 23 and are spaced at a predetermined distance from the annular limiting protrusion. For example, continuing with the example of four rollers to be installed, the number of positioning pins is set to four, and each positioning pin is evenly distributed along the circumference of the fixing point 23 and directly opposite the installation position of the roller 13 to be installed. That is, when the roller 13 is in the installation position, the positioning pin is directly below the roller 13 to facilitate the subsequent installation of the lower roller retainer 14. It should be noted that the installation of the lower roller retainer 14 will be described below.

[0069] Further, see also Figure 2 The support column is fitted with a drive nut 31 and a support ring 30 from bottom to top. The mounting surface has at least two through holes. The support ring 30 has a support rod that matches the number and position of the through holes. The diameter of the support rod is less than or equal to the diameter of the through holes.

[0070] The lower roller retainer 14 has mounting holes for fixing the rollers to be installed, which are the same number and position as the rollers to be installed. During the assembly of the planetary roller screw, the lower roller retainer 14 can be placed on the mounting surface, so that the mounting holes are fitted onto the positioning pins. When the rollers to be installed are pushed to the installation position (directly above the positioning pins), the drive nut 31 can be rotated to push the support ring 30 upward. The support pins on the support ring 30 push the lower roller retainer 14 upward, so that the lower end of the rollers to be installed is locked in the mounting holes of the lower roller retainer 14, thereby realizing the assembly of the lower roller retainer 14.

[0071] Furthermore, at least two through holes can be evenly distributed along the circumferential direction of the fixed 23 so that the lower roller retainer 14 will not tilt during the process of being lifted by the support ring 30.

[0072] Figure 5 A flowchart illustrating a planetary roller screw assembly method according to an embodiment of this application is shown. This method is applied to the aforementioned planetary roller screw assembly apparatus. See also... Figure 5 The method includes the following steps:

[0073] Step 501: Place the roller to be installed at the corresponding push block so that the threads on the roller to be installed and the threads on the push block are engaged.

[0074] Step 502: Rotate the threaded rod to make the tapered rod move upward. Under the action of the tapered rod, the push block pushes the roller to be installed outward, so that the threads of the roller to be installed and the threads of the nut are engaged after the roller to be installed and the nut are assembled.

[0075] Specifically, see [link to relevant documentation] Figure 2 The lower base 29 is mounted on the upper surface of the support platform 32. The support ring 30 is sleeved on the support column and fixed with the drive nut 31, so that the support rod on the support ring 30 extends into the through hole of the mounting surface but does not exceed the upper surface of the mounting surface. The lower roller retainer 14 is mounted on the upper surface of the mounting surface of the lower base 29, so that the mounting hole of the lower roller retainer 14 is sleeved on the positioning column of the mounting surface. The tapered rod is positioned in the initial position (the lower surface of the tapered rod is in contact with the mounting surface) by the threaded rod. The nut 15 of the planetary roller screw is placed on the mounting surface and limited by the annular limiting protrusion on the mounting surface. The roller 13 to be installed is placed at the corresponding push block, so that the threads on the roller to be installed and the threads on the push block are engaged. Rotating the handle 21 moves the tapered rod upward, and the tapered surface of the tapered rod acts on the tapered surface of the push block 27, so that the push block 27 pushes the roller 13 to be installed outward to the installation position. Since the threads on the push block 27 and the threads on the roller 13 to be installed are engaged, the roller 13 to be installed can be restricted from shifting in the vertical direction. Since the surface of the push block 27 and the roller 13 to be installed is concave, the roller 13 to be installed can be restricted from shifting in the horizontal direction.

[0076] After pushing the roller 13 to be installed to the installation position, rotate the drive nut 31 to drive the support ring 30 to move upward, so that the mounting hole on the lower roller retainer 14 is fitted onto the lower end of the roller 13 to be installed. Then install the upper roller retainer 12 and the snap ring 24 to complete the assembly of the planetary roller screw.

[0077] After the planetary roller screw is assembled, the planetary roller screw assembly device needs to be reset. To reset, simply turn the handle 21 in the opposite direction. Under the action of the threaded rod, the tapered rod returns to its initial position. Under the action of the extension spring 26, the push block 27 moves away from the roller. Finally, remove the assembled planetary roller screw from the assembly device and install the retaining spring at the lower roller cage 14, and rotate the screw 11 to install it.

[0078] In this embodiment, the rotation of the threaded rod drives the tapered rod to move upward. Under the action of the tapered rod, the push block moves outward along the radial direction of the fixed column, thereby pushing the roller to be installed to the nut for installation and fixation. Since the surface of the push block in contact with the roller to be installed has threads, the engagement between the threads on the push block and the threads on the roller to be installed allows for vertical positioning of the roller during the pushing process, thereby preventing the thread crests on the roller and the thread crests on the nut from being squeezed, thus avoiding damage to the planetary roller screw.

[0079] The above description is only a partial embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A planetary roller screw assembly device, characterized in that, include: The internal structure of the fixed column is hollow, with threaded holes on the top surface and openings on the side that match the number and position of the rollers to be installed; A drive rod includes a threaded rod and a tapered rod, the threaded rod being connected to the threaded hole, and the tapered rod being located inside the fixed column with its diameter gradually decreasing from bottom to top; The push block, which is slidably disposed at each of the openings, can slide back and forth along the radial direction of the fixed column. The side near the drive rod is a conical surface adapted to the tapered rod, and the side away from the drive rod has threads. The push block can move synchronously away from the drive rod under the upward movement of the tapered rod. The threaded side of the push block is an inwardly concave semi-cylindrical surface. A groove is provided on the semi-cylindrical surface, and a telescopic spring is provided in the groove; It also includes a lower base that is detachably connected to the fixed column, the lower base including a mounting surface having an annular limiting protrusion on the mounting surface; The mounting surface has the same number of positioning posts as the rollers to be installed. The positioning posts are evenly distributed around the circumference of the fixing posts and are at a preset distance from the annular limiting protrusion. The lower base also includes a support column fixedly connected to the mounting surface. The support column is fitted with a drive nut and a support ring from bottom to top. The mounting surface has at least two through holes. The support ring has a support rod that matches the number and position of the through holes. The diameter of the support rod is less than or equal to the diameter of the through holes.

2. The planetary roller screw assembly device according to claim 1, characterized in that, The fixed post, the threaded hole, and the drive rod are coaxial.

3. The planetary roller screw assembly device according to claim 1, characterized in that, The threaded rod is connected to a handle on the outer part of the fixed column.

4. The planetary roller screw assembly device according to claim 1, characterized in that, At least two of the through holes are evenly distributed along the circumferential direction of the fixed column.

5. A method for assembling a planetary roller screw, characterized in that, Applied to the planetary roller screw assembly device as described in any one of claims 1 to 4, the method comprises: Place the roller to be installed on the corresponding push block, so that the threads on the roller to be installed and the threads on the push block are engaged. Rotate the threaded rod to make the tapered rod move upward. Under the action of the tapered rod, the push block pushes the roller to be installed outward, so that the threads of the roller to be installed and the threads of the nut are engaged after the roller to be installed and the nut are assembled.

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