Wave spring and vacuum mechanical arm thereof
By designing wave springs with parallelogram cross-sections and asymmetric waveforms, the problem of insufficient bending cross-section coefficient of traditional wave springs is solved, and higher preloading force and more uniform stress distribution are achieved, which improves the motion accuracy and stability of vacuum robot arms.
Patent Information
- Application Number
- CN202422379528.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-29
- Publication Date
- 2025-06-17
- Estimated Expiration
- 2034-09-29
AI Technical Summary
The traditional rectangular cross-sectional wave spring has insufficient flexural cross-sectional coefficient and cannot stably meet the preload requirements of the semiconductor industry for angular contact bearings at the joints of vacuum robotic arm.
A wave spring formed by a strip-shaped plate body spirally wound along the central axis in a corrugated shape, the cross-section of the strip-shaped plate body is parallelogram, and is designed to adapt to the load distribution in different directions through asymmetrical design of peaks and troughs.
By increasing the bending cross-section coefficient, the wave spring can withstand greater bending stress, significantly improve preloading, reduce the compression amount caused by long-term compression, improve the bearing preload performance, and reduce vibration and noise.
Smart Images
Figure CN222992006U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of springs, in particular to a corrugated spring and a vacuum manipulator thereof. Background Art
[0002] In the process of semiconductor manufacturing, the high-precision and high-reliability operation of the vacuum manipulator is crucial. The preloading state of the angular contact bearings at the joints directly affects the motion accuracy, stability and service life of the manipulator.
[0003] At present, there are some limitations in the commonly used preloading schemes: for example, the thread preloading realizes preloading through the friction force between the thread pairs. This method has a simple structure, but it is difficult to adjust, and it is difficult to adapt to complex working conditions changes and is prone to looseness in occasions with high-precision requirements; while the hydraulic preloading scheme applies a preloading force to the bearing through the hydraulic system. Although the preloading force of this method is stable, the hydraulic system has a complex structure and high cost.
[0004] Therefore, the inventor considered using a corrugated spring pressing scheme to meet the preloading requirements of the angular contact bearings at the joints of the vacuum manipulator in the semiconductor industry. However, it was found through testing that the traditional corrugated spring with a rectangular cross-section still has insufficient bending section modulus and cannot stably meet the requirements of the bearing preloading force.
[0005] For this reason, there is an urgent need in this field for a solution to solve the problem of insufficient bending section modulus of the traditional corrugated spring. Summary of the Utility Model
[0006] For this reason, the main purpose of the present utility model is to provide a corrugated spring and a vacuum manipulator thereof to solve the problems mentioned in the background art.
[0007] To achieve the above object, according to one aspect of the present utility model, there is provided a corrugated spring, wherein the corrugated spring is formed by spirally winding a strip-shaped plate body in a corrugated undulating shape along the central axis. Each turn of the corrugated spring includes a plurality of wave crests and wave troughs, and the wave crests of the lower turn abut against the wave troughs of the upper turn. The cross-section of the strip-shaped plate body is a parallelogram.
[0008] In a possible preferred embodiment, the wave crests and wave troughs of each turn of the corrugated spring are asymmetrical.
[0009] In a possible preferred embodiment, the height of the wave crest is 1.2 mm and the height of the wave trough is 1.8 mm.
[0010] In a possible preferred embodiment, the inner diameter dimension of each turn of the corrugated spring is 19.51 mm, the outer diameter dimension is 23.87 mm, the thickness of the strip-shaped plate body is 0.25 mm, and the width is 2 mm.
[0011] In a possible preferred embodiment, the cross-section of the strip-shaped plate body is a parallelogram with an inner angle of 80°.
[0012] In a possible preferred embodiment, the strip-shaped plate body of each coil of the corrugated spring is inclined with respect to the central axis.
[0013] In a possible preferred embodiment, the strip-shaped plate body is inclined 10° with respect to the central axis.
[0014] In a possible preferred embodiment, the number of waves of the corrugated spring is 18.
[0015] In a possible preferred embodiment, the number of coils of the corrugated spring is greater than or equal to 3.
[0016] To achieve the above object, according to another aspect of the present invention, there is also provided a vacuum robotic arm, characterized in that at the bearing of the vacuum robotic arm, any one of the above corrugated springs is used for extrusion preloading.
[0017] Through the corrugated spring provided by the present invention, the cross-section of the strip-shaped plate body is ingeniously designed as a parallelogram structure. Thus, compared with the traditional circular or rectangular cross-section, it has a larger flexural section modulus, and can thus withstand a greater bending stress, significantly improving the preloading force provided by the corrugated spring. At the same time, it can also reduce the phenomenon that the compression amount of the corrugated spring does not meet the standard due to long-term compression, thereby overall improving the performance of the corrugated spring in bearing preloading. In addition, in the corresponding embodiment, through the asymmetric design of the wave crest and wave trough, it can better adapt to the load distribution in different directions, make the load distribution on the spring more uniform, reduce local stress concentration, so as to improve stability and deformation uniformity. At the same time, the unique elastic characteristics of the asymmetric waveform can also help to change the natural frequency of the system, reduce the possibility of resonance with external excitation, and thus reduce vibration and noise. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:
[0019] Figures 1 to 2 is a schematic structural diagram of the corrugated spring of the present invention;
[0020] Figure 3 is a half-sectional structural diagram of the corrugated spring of the present invention;
[0021] Figure 4 is Figure 3 an enlarged schematic diagram of the cross-sectional structure of the strip-shaped plate body at A in
[0022] Figure 5 This is a comparison test data graph of the cross-sectional stress of the corrugated spring of the present utility model and the stress of the traditional rectangular cross-section;
[0023] Figure 6 This is a comparison test data graph of the cross-sectional strain of the corrugated spring of the present utility model and the strain of the traditional rectangular cross-section;
[0024] Figure 7 This is a schematic structural diagram of the vacuum manipulator of the example of the present utility model;
[0025] Figure 8 This is a schematic semi-sectional structure diagram of the joint bearing of the vacuum manipulator of the example of the present utility model.
[0026] Description of the reference numerals
[0027] The first arm 1, the second arm 2, the third arm 3, the first joint bearing 4, the second joint bearing 5, the bearing pressure plate 6, the upper bearing 51, the lower bearing 52, the corrugated spring 9. Detailed implementation manners
[0028] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Apparently, the described embodiments are some but not all of the embodiments of the present utility model. Usually, the components of the embodiments of the present utility model described and shown in the accompanying drawings here can be arranged and designed in various different configurations.
[0029] Therefore, the following detailed description of the embodiments of the present utility model provided in the accompanying drawings is not intended to limit the scope of the claimed present utility model, but merely represents the selected embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.
[0030] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.
[0031] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present utility model is customarily placed during use. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model. In addition, terms such as "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance. The terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion.
[0032] In addition, terms such as "horizontal", "vertical", "suspended", etc. do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.
[0033] In the description of the present utility model, it should also be noted that unless otherwise clearly specified and limited, terms such as "set", "arranged", "installed", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances in combination with the prior art. In addition, without conflict, the embodiments and features in the embodiments of the present utility model can be combined with each other. And one or more of the components in the drawings can be necessary or unnecessary, and the relative positional relationship between the above-mentioned components in the drawings can be adjusted according to actual needs.
[0034] In view of the fact that the bending moment of inertia section coefficient of the traditional corrugated spring with a rectangular cross-section is still insufficient and cannot stably meet the preloading requirements of the angular contact bearings at the joints of the vacuum robot arms in the semiconductor industry. For this reason, as Figures 1 to 4 shown, the present utility model provides a corrugated spring solution, in which, as Figures 1 to 2 shown, the corrugated spring in this example is formed by spirally winding a strip-shaped plate body in a corrugated shape along the central axis. Each turn of the corrugated spring includes a plurality of wave crests and wave troughs, and the wave crests of the lower turn are arranged in contact with the wave troughs of the upper turn.
[0035] Since the existing vacuum robotic arm structure is relatively compact, in this example, a wave spring is required for preloading to greatly simplify the preloading structure and achieve effective preloading in a smaller space. However, the bending moment of inertia coefficient of the traditional wave spring per unit size is not sufficient to meet the requirements of the preloading force. Therefore, in this example, as Figures 3 to 4 shown, the cross-section of the strip-shaped plate can be set as a parallelogram.
[0036] For example, in the example solution, the cross-section of the strip-shaped plate can be set as a parallelogram with an inner angle of 80°, and the strip-shaped plate of each turn of the wave spring is inclined with respect to the central axis. Preferably, the strip-shaped plate is inclined 10° relative to the central axis. With this setting, compared with the traditional circular or rectangular cross-section, it will have a larger bending moment of inertia coefficient, so that it can withstand greater bending stress. At the same time, it can also improve the situation where the compression amount of the spring does not meet the standard due to long-term compression.
[0037] On the other hand, in order to make the wave spring better adapt to the load distribution in different directions, improve stability and achieve a uniform deformation effect, in this example, it is preferably designed that the wave peaks and wave valleys of each turn of the wave spring are asymmetric. With this design, it can better adapt to loads in different directions or sizes, make the load distribution on the spring more uniform, reduce local stress concentration, and at the same time, in combination with the parallelogram cross-section, it can further improve the service life and reliability of the spring.
[0038] In addition, it is worth mentioning that through the asymmetric design of the wave peaks and wave valleys, the resonance risk can also be reduced. The reason is that the unique elastic characteristics of the asymmetric waveform help to change the natural frequency of the system, thereby reducing the possibility of resonance with external excitation and reducing vibration and noise.
[0039] In this example, due to the compact structure of the existing vacuum robotic arm, the size requirements of the wave spring are relatively high. In order to meet the requirements of the preloading force, taking the inner diameter size D of the wave spring as 19.51 mm and the outer diameter size D as 23.87 mm as an example, considering the installation size and the spring compression amount (for example, the spring is compressed to 3.5 mm), the example height of the wave peak can be set as 1.2 mm, and the example height of the wave valley can be set as 1.8 mm. With this design, it is preferably set that the cross-section of the strip-shaped plate is a parallelogram with 2 mm * 0.25 mm and an inner angle of 80°. The material can be selected as 65Mn, the number of waves is 18, the number of effective turns is 3, and the strip-shaped plate is inclined 10° relative to the central axis.
[0040] With this setting, ANSYS is used to perform a force analysis on the traditional rectangular cross-section and the parallelogram cross-section spring with the same length and width dimensions respectively. The results are as Figures 5 to 6As shown, under the condition of the same acting force, the stress and strain of the parallelogram cross-section spring are both smaller than those of the conventional rectangular cross-section. Thus, it can be seen that the wave spring in this example has a larger bending section modulus, and can therefore withstand greater bending stress.
[0041] Through the above example, it can be found that the wave spring solution provided by the present utility model can achieve large elastic deformation in a limited space. Its special waveform and cross-section enable the stress distribution to be more uniform during the compression process, which can overall improve its fatigue resistance and thus extend its service life. The key parallelogram cross-section and the asymmetric waveform design enable the spring to have excellent stress uniform distribution and fatigue resistance, making the preload have a very small fluctuation range under long-term and high-frequency working conditions, thereby ensuring the high precision of the movement of the vacuum robotic arm.
[0042] In addition, it should be noted that although a cross-section solution of a parallelogram of a wave spring is exemplified in this example, in fact, the side lengths and angles of the parallelogram of this cross-section can also be adjusted according to specific design requirements to further optimize the spring performance or application scenarios. Thus, it can be seen that those skilled in the art can further modify and adjust various parameters on the basis of the concept of the present utility model. Therefore, for those skilled in the art, other alternative embodiments made without exceeding the scope of the inventive concept of this example are all within the disclosure scope of the present utility model.
[0043] On the other hand, corresponding to the above wave spring example, the present invention also provides a vacuum robotic arm, wherein at the bearing of the vacuum robotic arm, any one of the above wave springs is used for extrusion preloading.
[0044] Specifically, as Figures 7 to 8 shown, a vacuum robotic arm is exemplified. It uses the wave spring in the above example for preloading. Its example includes: a first arm 1, a second arm 2, a third arm 3, a first joint bearing 4, a second joint bearing 5, and a bearing pressing plate 6. The movement process of this vacuum robotic arm is as follows: through the reverse rotation of the up-and-down movement layer of the robot body, the two upper and lower first arms 1 are driven to move, the second arm 2 is driven to move through the first joint bearing 4. At this time, the movement is transmitted to the third arm 3 through the second joint bearing 5, so as to make the third arm 3 perform a left-right linear movement.
[0045] Taking the second spherical plain bearing 5 as an example, since the angular contact bearing method is adopted here, the second spherical plain bearing 5 includes: an upper bearing 51 and a lower bearing 52. Therefore, the two bearings need to be symmetrically installed. For example, the lower bearing 52 is installed on the bearing fixed shaft of the third arm 3 and then installed into the second arm 2. At this time, the shoulder of the bearing fixed shaft of the third arm 3 will fix the inner ring of the lower bearing 52, and the positioning hub on the second arm 2 will fix the outer ring of the lower bearing 52. Then the upper bearing 51 is installed. The positioning hub on the second arm 2 will fix the outer ring of the upper bearing 51. At this time, after the wave spring 9 of this example is installed into the card slot of the bearing pressure plate 6, the bearing pressure plate 6 is fixed on the third arm 3 with screws. Then the screws are tightened so that the edge part of the bearing pressure plate 6 is stuck on the second arm 2. At this time, the bearing pressure plate 6 presses down the wave spring 9, thereby bringing a pre-tightening force to the inner ring of the upper bearing 51. At the same time, under the action of the screws, the shoulder of the second arm 2 will also give a pre-tightening force to the inner ring of the lower bearing 52, so as to achieve the effect of stable pre-tightening of the two bearings.
[0046] According to actual use, the wave spring 9 of this example can stably meet the requirements of the bearing pre-tightening force of the vacuum robotic arm.
[0047] In summary, through the wave spring provided by the present utility model, the cross-section of the strip-shaped plate body is ingeniously designed as a parallelogram structure. Therefore, compared with the traditional circular or rectangular cross-section, it has a larger bending moment of inertia coefficient, and can thus withstand greater bending stress, significantly improving the pre-tightening force provided by the wave spring. At the same time, it can also reduce the phenomenon that the compression amount of the wave spring does not meet the standard due to long-term compression, thereby overall improving the performance of the wave spring in bearing pre-tightening. In addition, in the corresponding embodiment, through the asymmetric design of the wave crest and wave trough, it can better adapt to the load distribution in different directions, make the load distribution on the spring more uniform, reduce local stress concentration, so as to improve stability and deformation uniformity. At the same time, the unique elastic characteristics of the asymmetric waveform can also help to change the natural frequency of the system, reduce the possibility of resonance with external excitation, and thus reduce vibration and noise.
[0048] The preferred embodiments of the present utility model disclosed above are only used to help illustrate the present utility model. The preferred embodiments do not describe all the details in detail, nor do they limit the present utility model to the specific embodiments described. Obviously, according to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principle and practical application of the present utility model, so that those skilled in the relevant art can understand and utilize the present utility model well. The present utility model is only limited by the claims and their full scope and equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.
[0049] In addition, any combination can be made among various different embodiments of the embodiments of the present utility model, as long as it does not violate the idea of the embodiments of the present utility model, and it should also be regarded as the content disclosed by the embodiments of the present utility model.
Claims
1. A wave spring, characterized in that: The wave spring is formed by spirally winding a strip-shaped plate in a corrugated shape along a central axis, wherein each circle of the wave spring includes a plurality of crests and troughs, and the crests of the lower circle are offset against the troughs of the upper circle, wherein the cross-section of the strip-shaped plate is a parallelogram.
2. The wave spring according to claim 1, characterized in that: The wave crests and wave troughs of each circle of the wave spring are asymmetrical.
3. The wave spring according to claim 1, characterized in that: The wave crest height is 1.2 mm, and the wave trough height is 1.8 mm.
4. The wave spring according to claim 1, characterized in that: The inner diameter of each circle of the wave spring is 19.51 mm, and the outer diameter is 23.87 mm. The thickness of the strip-shaped plate is 0.25 mm and the width is 2 mm.
5. The wave spring according to claim 1, characterized in that: The cross section of the strip-shaped plate body is a parallelogram with an internal angle of 80°.
6. The wave spring according to claim 1, characterized in that: The strip-shaped plate body of each circle of the wave spring is inclined with respect to the central axis.
7. The wave spring according to claim 6, characterized in that: The strip plate body is inclined by 10° relative to the central axis.
8. The wave spring according to claim 1, characterized in that: The wave number of the wave spring is 18.
9. The wave spring according to claim 1, characterized in that: The number of turns of the wave spring is greater than or equal to 3.
10. A vacuum robot arm, characterized in that: The bearings of the vacuum robot arm are pre-loaded by means of a wave spring as described in any one of claims 1 to 9.