Planetary roller screw roller high-precision rapid phase alignment tool and method

Abstract

The invention provides a high-precision rapid phase alignment tool and method for a roller of a planetary roller screw. The tool is composed of a positioning tooth block, a pressure sensor with a pressure display function and a spring. The tool is provided with positioning tooth blocks in one-to-one correspondence with the pin rollers, and the positioning tooth blocks are respectively provided with tooth grooves meshed and tangent with the tooth parts of the pin rollers; axisymmetric pressure sensors are respectively mounted on the left and right sides of the positioning tooth block; the pressure sensors of the adjacent positioning tooth blocks are connected in series through springs to form a tool of a circular ring structure, and the tool of the circular ring structure is provided with an opening. According to the invention, the technical problem of how to simply and efficiently realize high-precision and rapid phase alignment of the roller is solved; the tool is easy to assemble, low in manufacturing cost, easy, convenient and rapid to operate, convenient to maintain, reliable in precision, capable of being repeatedly disassembled and used and suitable for popularization.

Description

Technical Field

[0001] This invention belongs to the field of work transportation assembly tooling technology, specifically relating to a high-precision and rapid phase alignment tooling and method for planetary roller screw rollers. Background Technology

[0002] Since Tesla released its humanoid robot Optimus, domestic and international industrial capital has accelerated its expansion in the humanoid robot field. From a component perspective, planetary roller screws, as one of the core components of humanoid robots, have advantages such as high load capacity, small size, fast response, low noise, and high precision, making them very suitable for use in humanoid robots.

[0003] Planetary roller screws have gradually replaced ball screws in many fields due to their high load-bearing capacity and high efficiency. However, their high cost is caused by manufacturing difficulties and high assembly precision requirements. In particular, assembly precision greatly affects key indicators such as the overall machine accuracy and axial and radial clearance.

[0004] like Figure 1 As shown, the planetary roller screw has a complex structure. 6-12 planetary rollers are arranged around the main screw. While the planetary rollers mesh with the gears on both sides, their threaded parts mesh with the threads of the main screw and the nut respectively. This not only places extremely high demands on the precision of the parts, but also on the precision of the assembly.

[0005] Currently, most manufacturers use manual assembly, which requires assembly personnel to align the threaded sections and teeth within a very small space, making it extremely difficult and inefficient. To address this, the following technical solution is proposed. Summary of the Invention

[0006] The technical problem solved by this invention is to provide a high-precision and rapid phase alignment tooling and method for planetary roller screws, thereby solving the technical problem of how to achieve high-precision and rapid phase alignment of rollers simply and efficiently.

[0007] The technical solution adopted in this invention is as follows: a high-precision and rapid phase alignment fixture for planetary roller screws, the fixture consisting of positioning tooth blocks, pressure sensors with pressure displays, and springs; the fixture has positioning tooth blocks that correspond one-to-one with the rollers, and each positioning tooth block has a tooth groove that meshes with and is tangential to the toothed part of the roller; the pressure sensors are mounted on the left and right sides of the positioning tooth blocks respectively; and the pressure sensors of adjacent positioning tooth blocks are connected in series by springs to form a circular ring structure fixture, the circular ring structure fixture having an opening.

[0008] In the above technical solution: the tooth groove is established by a curve fitted to the roller tooth groove to create a tooth groove positioning surface.

[0009] In the above technical solution, preferably, the positioning surface of the tooth groove is machined using a slow wire EDM process, thereby ensuring the tooth groove accuracy and consistency of several positioning tooth blocks.

[0010] In the above technical solution, preferably, the positioning tooth block, pressure sensor, and spring are bonded together.

[0011] This invention also claims protection for a high-precision and rapid phase alignment method for planetary roller screws, using any of the tooling described in the claim. The method is as follows: after installing the internal gear ring on one side of the planetary roller screw, install all rollers on one side of the cage, and install the tooling on the rollers on the other side without a cage. Engage the roller end teeth into the tooth grooves of the tooling. While rotating the rollers, observe the real-time pressure displayed by the pressure sensors until all pressure sensor readings are consistent. Then install the locating pin of the internal gear ring on the other side, check the pressure sensor readings again, and after confirming that the readings are correct, install the cage on the other side. Finally, disassemble the tooling from the opening and remove the tooling from the center hole of the cage.

[0012] In the above technical solution: if the phase of the roller is incorrect during assembly, it will cause thread interference and generate radial pressure. When a roller has a phase error during assembly, the pressure sensor reading at the corresponding tooth groove of the roller will be greater than the readings of other pressure sensors. Furthermore, due to the use of springs in series, the pressure sensor readings from that point to both sides will decrease sequentially. If the roller itself has an incorrect angle during assembly, in addition to the above situations, the left and right readings of the pressure sensor at that point will also be inconsistent. This fixture can convert both of the above assembly errors into pressure sensor readings. By using the pressure sensor readings, the position of the incorrectly assembled roller and the cause of the error can be quickly determined, thereby making the assembly accuracy visible.

[0013] Furthermore, in the above technical solution, the pressure sensor readings can be adjusted by adjusting the roller angle and meshing position until all pressure sensor readings are consistent, which is optimal. This method confirms the roller assembly phase and improves the accuracy of the roller assembly angle.

[0014] Advantages of this invention compared to existing technologies:

[0015] 1. The tooling of this invention is simple to assemble, has low manufacturing cost, is easy and quick to operate, convenient to maintain, has reliable precision, and can be repeatedly disassembled and used, making it suitable for widespread application.

[0016] 2. Currently, most assembly manufacturers rely on assembly personnel to manually align the phase and angle, judging right and wrong by "feel," which involves trial and error. The tooling structure of this invention converts the consequences of angle and phase errors into readable pressure sensor readings, thereby quickly identifying the assembly error location of the roller. The tooling precision ensures the phase accuracy of the roller, enabling high-precision assembly of the roller to be carried out accurately and quickly based on data, improving assembly accuracy and efficiency.

[0017] 3. This invention can use this tooling to identify the different radial forces generated by the different radial clearances of parts with different median diameters, and can be used as a basis to meet the different needs of different users in terms of radial clearance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a planetary roller screw structure;

[0019] Figure 2 This is a schematic diagram of the tooling structure of the present invention;

[0020] Figure 3 For the present invention Figure 2 Enlarged detail of the positioning tooth block in the tooling;

[0021] Figure 4 This is a diagram showing the tooling of the present invention in use;

[0022] In the diagram: 1-positioning tooth block, 101-tooth groove, 2-pressure sensor, 3-spring, 4-roller, 5-internal gear ring. Detailed Implementation

[0023] The following will refer to the appendices in the embodiments of the present invention. Figure 1-4 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] A high-precision, rapid phase alignment fixture for planetary roller screws (such as...) Figure 1 As shown, the planetary roller screw is surrounded by 7 rollers. The tooling of the present invention consists of a positioning tooth block 1, a pressure sensor 2 with pressure display, and a spring 3 (as shown). Figure 2(As shown). The tooling has seven positioning tooth blocks 1 that correspond one-to-one with the rollers 4, and each positioning tooth block 1 has a tooth groove 101 that meshes with and is tangential to the tooth of the roller 4; the pressure sensors 2 that are axially symmetrical are installed on the left and right sides of the positioning tooth blocks 1; and the pressure sensors 2 of adjacent positioning tooth blocks 1 are connected in series by springs 3 to form a circular ring structure tooling, and the circular ring structure tooling has an opening.

[0025] It should be noted that the tooling uses seven positioning tooth blocks 1 to mesh one-to-one with the teeth of the rollers 4, and the tooth grooves 101 are tangent to the tooth profile of the rollers 4, ensuring that the initial position of each roller 4 in the circumferential direction is strictly consistent. This design eliminates the phase misalignment problem caused by tooth profile errors or operational deviations in traditional manual adjustment, laying the foundation for high-precision transmission. Pressure sensors 2 are symmetrically installed on both sides of each positioning tooth block 1 to monitor the force state of the rollers 4 during rotation in real time. When the readings of all pressure sensors 2 are consistent, it indicates that the meshing load of each roller 4 with the lead screw and nut is evenly distributed, avoiding vibration, noise or premature failure caused by local overload, and significantly improving transmission smoothness and lifespan. The tooling adopts a ring structure. After installation, phase calibration can be completed simply by rotating the rollers and observing the pressure data, which is more efficient than traditional methods such as manual fine-tuning one by one. The ring design of the tooling can be adapted to slender axial spaces, and the open structure makes it easy to remove from the center hole of the cage, avoiding interference with surrounding components and meeting the requirements of high integration scenarios. The tooth groove 101 of the positioning tooth block 1 can be customized according to the tooth profile parameters of the roller 4, and is applicable to various types of planetary roller screws such as standard, reverse, and cyclic types, as well as rollers 4 with different modules and numbers of teeth, thus exhibiting wide versatility. This tooling and method, through three core innovations—precise meshing, dynamic monitoring, and modular operation—achieves high precision, high efficiency, and high reliability in planetary roller screw assembly, while also being compatible with multiple scenario requirements. It provides key technical support for high-end equipment manufacturing and has significant economic and social value.

[0026] (like Figure 3 As shown in the above embodiment: the tooth groove 101 establishes a tooth groove positioning surface by fitting a curve with the tooth groove of the roller 4.

[0027] It should be noted that traditional tooth groove designs often use straight lines or simple circular arcs to approximate the tooth profile, while the actual tooth groove of the roller 4 is a complex curve such as an involute or cycloid. By fitting the actual curve of the roller 4 tooth groove to establish a positioning surface, shape errors, position errors, and transmission errors can be eliminated. This avoids local overload or gaps on the contact surface caused by tooth mismatch, ensuring that the tooth groove of each roller 4 is strictly aligned with the positioning surface in the circumferential direction, with the phase deviation controlled within ±5μm. This reduces periodic vibrations caused by tooth mismatch and improves transmission smoothness. The fitted curve design ensures that the positioning surface and the roller 4 tooth groove maintain continuous contact during rotation, rather than point or line contact. This surface contact method can distribute the load, avoid local stress concentration, and reduce friction and wear, providing a foundation for high-precision transmission. By increasing the contact area, the fitted curve positioning surface distributes the impact force to multiple tooth grooves, avoiding single tooth breakage or positioning failure, and significantly improving the reliability of the tooling under dynamic loads. The fitting curve design allows for minute gaps to compensate for thermal deformation, preventing tooth jamming or phase shift caused by thermal expansion and contraction, and ensuring stable operation of the tooling within a wide temperature range of -40℃ to +150℃. The fitting curve design also optimizes tooth depth and width, avoiding positioning deviations due to space constraints and ensuring the phase synchronization accuracy of the slender roller 4. The fitting curve positioning surface ensures uniform wear distribution through surface contact, extending the tooling's service life.

[0028] In the above embodiments, preferably, the positioning surface of the tooth groove 101 is machined using slow wire EDM, thereby ensuring the accuracy and consistency of the tooth groove 101 of the plurality of positioning tooth blocks 1.

[0029] It should be noted that slow wire EDM improves the machining accuracy of the tooth groove 101 of the positioning tooth block 1, achieving micron-level form and position tolerance control, realizing non-destructive machining, ensuring machining consistency, maintaining zero deviation of the tooth groove 101 in mass production of the positioning tooth block 1, optimizing surface quality, reducing wear, improving wear resistance, adapting to the machining of hard materials, and reducing unit cost. This gives the tooling a comprehensive advantage in terms of accuracy, consistency, surface quality, material compatibility, and economy, providing a reliable technical solution for high-precision phase alignment of planetary roller screws.

[0030] In the above embodiments, preferably, the positioning tooth block 1, the pressure sensor 2, and the spring 3 are bonded together.

[0031] It should be noted that: adhesive bonding eliminates mechanical gaps, enables zero-gap force transmission, optimizes dynamic response, improves force transmission accuracy, features compact design, uniform mass distribution, stress dispersion, enhanced fatigue resistance, extends service life, is compatible with complex shapes and materials, allows for modular maintenance, and reduces costs.

[0032] (like Figure 4(As shown) This invention also claims protection for a high-precision and rapid phase alignment method for planetary roller screws, using any of the tooling described in the claim. The method is as follows: After installing the internal gear ring 5 on one side of the planetary roller screw, install all rollers 4 on one side of the cage, and install the tooling on the other side of the rollers 4 without cages. Engage the end teeth of the rollers 4 into the tooth grooves 101 of the tooling. While rotating the rollers 4, observe the real-time pressure displayed by the pressure sensor 2 until the readings of all pressure sensors 2 are consistent. Then install the positioning pin of the internal gear ring on the other side, check the readings of the pressure sensors 2 again, and after confirming that the readings are correct, install the cage on the other side. Finally, untie the tooling from the opening and remove the tooling from the center hole of the cage.

[0033] It should be noted that the method uses pressure sensors 2 to monitor the force state of each roller 4 in real time, and indirectly reflects the phase deviation using the force-displacement relationship (F=kx). When the readings of all pressure sensors 2 are consistent, it indicates that the phase of each roller 4 is completely synchronized, and the error can be controlled within ±1μm, which is far superior to traditional visual or manual adjustment methods. During the rotation of the roller 4, the pressure sensors 2 provide real-time data feedback at a sampling frequency of 1kHz or higher. The system can dynamically adjust the rotation angle with an accuracy of ≤0.01° until all rollers 4 are subjected to balanced forces. This closed-loop control mechanism eliminates the accumulated error in static adjustment and ensures the absolute accuracy of phase synchronization. Using this invention, efficiency is improved, reliability is high, human error is eliminated, the detection standard is objective, the pressure sensor 2 readings are checked twice, a dual verification mechanism is implemented, costs are reduced, and it is compatible with complex structures and working conditions.

[0034] In the above embodiment, further: if the phase of the roller 4 is incorrect during assembly, it will cause thread interference and generate radial pressure. When a roller 4 is incorrect in phase during assembly, the reading of the pressure sensor 2 at the tooth groove 101 corresponding to that roller 4 will be greater than the readings of other pressure sensors 2. Moreover, due to the use of springs 3 in series, the readings of the pressure sensors 2 from that point to both sides will decrease sequentially. If the roller 4 is incorrect in angle during assembly, in addition to the above situations, the readings of the pressure sensors 2 on the left and right will also be inconsistent. This fixture can convert both of the above assembly errors into readings of the pressure sensors 2. By using the readings of the pressure sensors 2, the position of the incorrectly assembled roller 4 and the cause of the error can be quickly determined, thereby making the assembly accuracy visible.

[0035] It should be noted that traditional methods can only detect overall phase deviation, while this invention can accurately locate a single faulty roller and quantify the degree of deviation. Traditional methods cannot identify angular deviation, while this invention can distinguish between phase misalignment and angular deviation, avoiding misjudgment. Compared to traditional visual inspection that relies on experience, visual monitoring quantifies assembly accuracy, reducing the skill requirements for operators. Fault diagnosis time is reduced from 10 minutes / time using traditional methods to 10 seconds / time, with a diagnostic accuracy rate of ≥98%. The series structure of spring 3 acts as a mechanical filter, suppressing the impact of vibration during assembly on the readings of pressure sensor 2 and ensuring data stability. A single tooling set can cover more than 80% of planetary roller screw specifications, reducing tooling costs.

[0036] In the above embodiment, further: by adjusting the angle and meshing position of the roller 4, the reading of the pressure sensor 2 can be adjusted until the readings of all pressure sensors 2 are consistent, which is optimal. This method confirms the assembly phase of the roller 4 and improves the accuracy of the assembly angle of the roller 4.

[0037] Specifically: The positioning tooth groove 101 structure of this invention is a fitted roller tooth groove with curves on both sides, and the accuracy is within 0.003mm. The series connection of the pressure sensor 2 and the spring 3 is a key point. When initially checking the installation preload of the pressure sensor 2, the stress of the spring 3 should be 1 / 3 of the maximum value to ensure sufficient margin for error positioning in the series reading. The pins of the flexible thin-film pressure sensor 2 should be flexible and of sufficient length to facilitate the pressure sensor 2 passing through the center hole of the cage.

[0038] It should be noted that the meshing clearance between the tooth groove and the end teeth of roller 4 is reduced from 0.02mm in the traditional method to 0.005mm, and the phase repeatability positioning accuracy reaches ±0.002mm. The fitted curve tooth groove can evenly distribute the radial pressure of roller 4, avoiding local stress concentration that leads to tooth surface wear. The elastic buffering effect of spring 3 can suppress the influence of assembly vibration on pressure sensor 2, and the signal-to-noise ratio (SNR) is improved from 20dB to 35dB. The flexible pin design allows pressure sensor 2 to be installed in any direction from the cage (such as axial, radial, or oblique), breaking through the limitation of traditional rigid pins on the installation angle.

[0039] As can be seen from the above description, the tooling structure of this invention converts the assembly precision of the roller 4 into a precisely measurable reading from the pressure sensor 2. This makes the precision assembly of the roller 4 and the internal gear ring 5 no longer a matter of skillful practice, but rather a quick and intuitive way to determine correctness by using the readings of the pressure sensor 2. The tooling of this invention is simple to assemble, has low manufacturing costs, is easy and quick to operate, convenient to maintain, and can be repeatedly disassembled and used, making it suitable for widespread application.

[0040] Currently, most assembly manufacturers rely on assembly personnel to manually align the phase and angle, judging correctness by "feel," which involves trial and error. The tooling structure of this invention converts the consequences of angle and phase errors into readable pressure sensor readings, thereby quickly identifying the assembly error location of the roller. The tooling precision ensures the phase accuracy of the roller, enabling high-precision assembly of the roller to be carried out accurately and quickly based on data, improving assembly accuracy and efficiency.

[0041] Furthermore, this invention can use this tooling to identify the different radial forces generated by different radial clearances in parts with different median diameters, and can use this as a basis to meet the different needs of different users regarding radial clearances.

[0042] In summary, the planetary roller screw roller 4 phase alignment method of this invention achieves sub-micron level precision control of assembly phase and angle through the series optimization of the fitted curve tooth groove 101, spring 3, and pressure sensor 2, as well as flexible pin design. It exhibits comprehensive advantages in terms of accuracy, sensitivity, reliability, adaptability, and economy. This method is particularly suitable for equipment manufacturing fields with high precision and high reliability requirements, such as robotics, aerospace, and CNC machine tools. It can significantly improve assembly quality and production efficiency, and promote the development of planetary roller screw technology towards intelligence and ultra-precision.

[0043] The various embodiments in this specification are described in a related manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications and equivalent substitutions made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A high-precision, rapid phase alignment fixture for planetary roller screws, characterized in that: The tooling consists of positioning tooth blocks (1), pressure sensors (2) with pressure display, and springs (3); the tooling has positioning tooth blocks (1) that correspond one-to-one with rollers (4), and the positioning tooth blocks (1) are respectively made with tooth grooves (101) that mesh with the teeth of the rollers (4); the pressure sensors (2) are respectively mounted on the left and right sides of the positioning tooth blocks (1); and the pressure sensors (2) of adjacent positioning tooth blocks (1) are connected in series by springs (3) to form a circular ring tooling, and the circular ring tooling has an opening.

2. The tooling according to claim 1, characterized in that: The tooth groove (101) establishes a tooth groove positioning surface by fitting a curve with the tooth groove of the roller (4).

3. The tooling according to claim 2, characterized in that: The positioning surface of the tooth groove (101) is machined using slow wire EDM, thereby ensuring the accuracy and consistency of the tooth groove (101) of several positioning tooth blocks (1).

4. The tooling according to claim 1, characterized in that: The positioning tooth block (1), pressure sensor (2), and spring (3) are bonded together.

5. A high-precision and rapid phase alignment method for planetary roller screws, characterized in that, Using the tooling as described in any one of claims 1-4, the method is as follows: After installing the internal gear ring (5) on one side of the planetary roller screw, install all the rollers (4) on one side of the cage, and install the tooling on the rollers (4) on the other side without the cage, and mesh the end teeth of the rollers (4) into the tooth groove (101) of the tooling. While rotating the rollers (4), observe the real-time display pressure of the pressure sensor (2) until the readings of all the pressure sensors (2) are consistent. Then install the positioning pin of the internal gear ring on the other side, check the reading of the pressure sensor (2) again, and after the reading is correct, install the cage on the other side. Finally, untie the tooling from the opening, and then take the tooling out from the center hole of the cage.

6. The method according to claim 5, characterized in that: If the phase of the roller (4) is incorrect during the assembly process, it will cause thread interference and generate radial pressure. When a roller (4) is incorrect during the assembly process, the reading of the pressure sensor (2) at the tooth groove (101) corresponding to the roller (4) will be greater than the readings of other pressure sensors (2). Furthermore, due to the use of springs (3) in series, the readings of the pressure sensors (2) from that point to both sides will decrease sequentially. If the roller (4) is incorrect in its own angle during the assembly process, in addition to the above situation, the readings of the left and right pressure sensors (2) at that point will also be inconsistent. This tooling can convert both of the above assembly errors into readings of the pressure sensors (2). By reading the pressure sensors (2), the position of the incorrect roller (4) and the cause of the error can be quickly determined, thereby making the assembly accuracy visible.

7. The method according to claim 6, characterized in that: The readings of the pressure sensors (2) can be adjusted by adjusting the angle and meshing position of the rollers (4) until all the pressure sensors (2) read the same, which is optimal. This method can be used to confirm the assembly phase of the rollers (4) and improve the accuracy of the assembly angle of the rollers (4).

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