Double nut anti-loose assembly and rail transit vehicle

Abstract

This invention provides a double-nut anti-loosening assembly and a rail transit vehicle, relating to the field of fastener anti-loosening. This anti-loosening assembly adds a fitting washer to the double-nut anti-loosening structure. The fitting washer includes a first washer and a second washer that can rotate relative to each other, forming a split structure. The first washer and the second washer are fitted together by a first nut and a second nut, i.e., the first nut abuts against the first washer, and the second nut abuts against the second washer. Further, the frictional force between the first washer and the second washer is set to F1, the frictional force between the first nut and the first washer to F2, and the frictional force between the second nut and the second washer to F3, where F1 < F2 and F1 < F3. Thus, when a loosening tendency occurs, the first washer and the second washer of the fitting washer preferentially rotate relative to each other, thereby preventing the first nut and the second nut from loosening simultaneously, effectively increasing the reliability and stability of this anti-loosening assembly.

Description

Technical Field

[0001] This application relates to the field of fastener anti-loosening, and in particular to a double-nut anti-loosening component and a rail transit vehicle. Background Technology

[0002] Threaded fasteners are one of the most basic and widely used connection methods in fields such as rail transportation, mechanical engineering, automobile manufacturing, and aerospace. For example, in rail vehicles, the box-type equipment located under the car body is hoisted to the car body through threaded connections. However, after long-term use, the two components connected by threads will slide relative to each other, causing radial sliding between the internal and external threads. According to the friction circle effect (when an object has already slid in one direction, its sliding frictional resistance in the vertical direction will become very small), the threaded fasteners will loosen.

[0003] Currently, to ensure the stability and reliability of the connection between two components, anti-loosening designs are usually added between threaded fasteners. Commonly used anti-loosening structures include double-nut anti-loosening structures or cotter pin mechanical locking structures. However, under current process conditions, it is difficult to ensure that all double nuts can achieve a fully pre-tightened state, and the anti-loosening effect cannot be guaranteed. The latter requires the openings to be aligned, which will cause the tightening torque to deviate from the target value, amplify the dispersion of the pre-tightening force, and is not conducive to the realization of the fastening structure function. In addition, there are also anti-loosening methods such as locking adhesive and adding washers, but the above-mentioned anti-loosening structures generally rely on uncontrollable friction or distance deformation to prevent loosening, resulting in poor consistency of pre-tightening force (for example, when using the same torque wrench to tighten the same batch of parts with the same torque, some parts can be tightened while others cannot), thus making it difficult for existing anti-loosening structures to simultaneously achieve consistency of pre-tightening force and reliability of anti-loosening. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a double-nut anti-loosening component and a rail transit vehicle to solve the problem that existing anti-loosening structures for threaded connections are difficult to balance preload consistency and anti-loosening reliability.

[0005] In accordance with the above objectives, a first aspect of the present invention provides a double-nut anti-loosening assembly, wherein the double-nut anti-loosening assembly comprises: A bolt, wherein a first nut and a second nut are screwed onto the outer side of the bolt; A fitting washer is fitted onto the outer side of the bolt and located between the first nut and the second nut; the fitting washer includes a first washer and a second washer that are rotatable relative to each other; the first nut abuts against the first washer, and the second nut abuts against the second washer; Let F1 be the frictional force between the first washer and the second washer, F2 be the frictional force between the first nut and the first washer, and F3 be the frictional force between the second nut and the second washer, where F1 < F2 and F1 < F3.

[0006] Preferably, the first washer is formed into a conical structure, and the second washer is formed with a conical recess that corresponds to and matches the first washer, so that the first washer and the second washer are nested in a corresponding manner.

[0007] Preferably, the outer wall of the first washer abuts against the inner wall of the conical recess of the second washer, and the frictional force between the outer wall of the first washer and the inner wall of the conical recess of the second washer is F1.

[0008] Preferably, a lubricating layer is formed between the outer portion of the first washer and the inner sidewall of the conical recess of the second washer.

[0009] Preferably, along the axial direction of the first washer, the first washer is formed with a large-diameter end and a small-diameter end, and the first nut abuts against the end face of the large-diameter end.

[0010] Preferably, the angle between the generatrix of the outer side wall of the first washer and the end face of the small diameter end is set to ∠A, and the thread helix angle of the bolt is set to ∠B, where ∠A > ∠B.

[0011] Preferably, the first washer has a first through hole, which extends axially along the first washer and passes through the large-diameter end and the small-diameter end; the first washer is sleeved on the outer side of the bolt through the first through hole, and the first washer and the bolt form a clearance fit.

[0012] Preferably, along the axial direction of the second washer, the tapered recess is formed on the end face of the first end of the second washer; the second nut abuts against the end face of the second end of the second washer.

[0013] Preferably, the second washer has a second through hole, which extends along the axial direction of the second washer and passes through both axial ends of the second washer; the second washer is sleeved on the outer side of the bolt through the second through hole, and the second washer and the bolt form a clearance fit.

[0014] According to a second aspect of the present invention, a rail transit vehicle is provided, comprising a car body and a housing device located below the car body, wherein the housing device is correspondingly connected to the car body by a double-nut anti-loosening assembly as described above.

[0015] According to the double-nut anti-loosening assembly and rail transit vehicle of the present invention, the anti-loosening assembly adds a fitting washer to the double-nut anti-loosening structure. The fitting washer includes a first washer and a second washer that can rotate relative to each other to form a split structure. The first washer and the second washer are fitted together by the first nut and the second nut, that is, the first nut abuts against the first washer and the second nut abuts against the second washer. Further, the frictional force between the first washer and the second washer is set to F1, the frictional force between the first nut and the first washer is F2, and the frictional force between the second nut and the second washer is F3, where F1 < F2 and F1 < F3. In this way, when a loosening tendency occurs, the first washer and the second washer of the fitting washer will preferentially rotate relative to each other, thereby avoiding the situation where the first nut and the second nut loosen at the same time, effectively increasing the reliability and stability of the anti-loosening assembly. Furthermore, since the first and second washers can rotate relative to each other and the friction between them is relatively small, discrete and uncontrollable support surface friction is not introduced during the tightening of the first and second nuts. As a result, the fluctuation of axial preload is significantly reduced under the same tightening torque, which effectively improves the consistency of preload. Moreover, since the first and second washers preferentially rotate relative to each other when loosening occurs, the loosening energy can be consumed, effectively reducing the wear between the nut and bolt thread pair and between the nut and the mating washer. As a result, the remaining axial preload at each fastening point of this anti-loosening component can still maintain a high degree of consistency after long-term vibration.

[0016] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a partial schematic diagram of a double-nut anti-loosening assembly according to an embodiment of the present invention; Figure 2 This is an exploded view of a fitting washer according to an embodiment of the present invention; Figure 3 This is a cross-sectional view of the double-nut anti-loosening assembly after assembly according to an embodiment of the present invention.

[0019] Icons: 1- Bolt; 21- First nut; 22- Second nut; 3- Fitting washer; 31- First washer; 311- First through hole; 32- Second washer; 321- Conical recess; 322- Second through hole; 4- Flat washer. Detailed Implementation The following detailed embodiments are provided to help the reader gain a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will be apparent after understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein; changes that will be apparent after understanding the disclosure of this application are possible, except for operations that must occur in a specific order. Furthermore, for clarity and brevity, descriptions of features known in the art may be omitted.

[0020] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0021] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, it may be directly "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, or there may be one or more other elements in between. In contrast, when an element is described as being "directly on" another element, "directly connected to" another element, "directly bonded to" another element, "directly on" another element, or "directly covering" another element, there may be no other elements in between.

[0022] As used herein, the term “and / or” includes any one of the relevant items listed and any combination of any two or more items.

[0023] Although terms such as “first,” “second,” and “third” may be used herein to describe individual components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts are not limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Therefore, without departing from the teachings of the examples described herein, the first component, assembly, region, layer, or part referred to as the second component, assembly, region, layer, or part may also be referred to as the second component, assembly, region, layer, or part.

[0024] For ease of description, spatial relation terms such as “above,” “upper,” “below,” and “lower” are used herein to describe the relationship between one element and another, as shown in the accompanying drawings. Such spatial relation terms are intended to include not only the orientation depicted in the drawings but also different orientations of the device during use or operation. For example, if the device in the drawings is flipped, an element described as being “above” or “upper” relative to another element will subsequently be “below” or “lower” relative to that other element. Therefore, the term “above” includes both “above” and “below” orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relation terms used herein will be interpreted accordingly.

[0025] The terminology used herein is for the purpose of describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms “comprising,” “including,” and “having” enumerate the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0026] Variations in the shapes shown in the accompanying drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the accompanying drawings, but include changes in shape that may occur during manufacturing.

[0027] The features of the examples described herein can be combined in various ways that will be apparent upon understanding the disclosure of this application. Furthermore, although the examples described herein have a wide variety of constructions, other constructions are possible, as will be apparent upon understanding the disclosure of this application.

[0028] The first aspect of the present invention provides a double-nut anti-loosening assembly, such as... Figures 1 to 3As shown, the anti-loosening component in this embodiment includes a bolt and a first nut 21, a second nut 22, and a fitting washer 3 sleeved on the outer side of the bolt. Specifically, along the axial direction of the bolt, the fitting washer 3 is located between the first nut 21 and the second nut 22. The fitting washer 3 includes a first washer 31 and a second washer 32 that can rotate relative to each other. The first washer 31 and the second washer 32 are also arranged sequentially along the axial direction of the bolt, and the first nut 21 abuts against the first washer 31, and the second nut 22 abuts against the second washer 32. The frictional force between the first washer 31 and the second washer 32 is set as F1, the frictional force between the first nut 21 and the first washer 31 is set as F2, and the frictional force between the second nut 22 and the second washer 32 is set as F3. Correspondingly, F1 < F2, F1 < F3. Thus, when a loosening tendency occurs, the first washer 31 and the second washer 32 will preferentially rotate relative to each other, thereby preventing the first nut 21 and the second nut 22 from loosening simultaneously. This effectively increases the reliability and stability of the anti-loosening assembly and also increases the consistency of the preload of the anti-loosening assembly.

[0029] Furthermore, since the first washer 31 and the second washer 32 can rotate relative to each other and the friction between them is relatively small, discrete and uncontrollable support surface friction is not introduced during the tightening of the first nut 21 and the second nut 22. As a result, the fluctuation of axial preload is significantly reduced under the same tightening torque, which effectively improves the consistency of preload. Moreover, since the first washer 31 and the second washer 32 preferentially rotate relative to each other when there is a tendency to loosen, the loosening energy can be consumed, effectively reducing the wear between the nut and bolt thread pair and the contact surface between the nut and the fitting washer 3. As a result, the remaining axial preload at each fastening point of this anti-loosening component can still maintain a high degree of consistency after long-term vibration.

[0030] Furthermore, in this embodiment, as Figure 2 As shown, the first washer 31 is formed into a conical structure, and the outer contour of the second washer 32 is formed into a disk-shaped structure, and it has a conical recess 321 that corresponds to and fits the first washer 31, so that the first washer 31 can be nested with the second washer 32. When the first washer 31 and the second washer 32 are nested, the outer wall of the first washer 31 abuts against the inner wall of the conical recess 321 of the second washer 32, that is, the outer wall of the first washer 31 and the inner wall of the conical recess 321 of the second washer 32 are their contact surfaces, and the frictional force between the outer wall of the first washer 31 and the inner wall of the conical recess 321 of the second washer 32 is F1.

[0031] Based on the conical mating structure of the first washer 31 and the second washer 32 in this embodiment, the mating washer 3 has a self-centering function. That is, after the first washer 31 and the second washer 32 come into contact, they can automatically slide along the conical surface to a concentric position, thereby ensuring that the load can be transmitted along the axial direction of the bolt, and thus effectively resisting the lateral force generated by factors such as vibration, so as to avoid the bolt being sheared and increase the service life of this anti-loosening structure. Its self-centering function can also eliminate the preload fluctuation caused by eccentricity. In addition, the first washer 31 and the second washer 32 make the stress distribution more uniform through the conical contact, so that the axial force fluctuation generated under the same torque is smaller. When loosening occurs, the first washer 31 and the second washer 32 preferentially rotate relative to each other at the conical surface, and the wear position is controllable without affecting the preload.

[0032] Preferably, in this embodiment, a lubricating layer is formed between the outer side of the first washer 31 and the inner sidewall of the conical recess 321 of the second washer 32. For example, grease (such as lithium-based, barium-based, hydrocarbon-based, and calcium-based greases, etc., can be pre-applied to the conical mating surface to match different nuts) can be applied. This can further reduce the friction between the conical mating surfaces of the first washer 31 and the second washer 32, and is more conducive to achieving the above-mentioned technical effects.

[0033] More specifically, in this embodiment, as Figures 2 to 3 As shown, along the axial direction of the first washer 31, the first washer 31 has a large-diameter end and a small-diameter end, and the first nut 21 actually abuts against the end face of the large-diameter end of the first washer 31. The angle between the generatrix of the outer wall of the first washer 31 and the end face of its small-diameter end is set to ∠A, and the thread helix angle of the bolt 1 is set to ∠B, where ∠A > ∠B. Thus, when the nut is subjected to vibration or lateral external load and shows a tendency to loosen, the second washer 32 will tend to climb upwards and expand radially along the conical outer wall of the first washer 31, thereby increasing the pressure on the conical outer wall of the first washer 31. The axial force borne by the bolt between the first nut 21 and the second nut 22 tends to increase. This increase in axial force will simultaneously increase the rotational resistance between the threaded pair and the contact surface between the nut and the mating washer 3, forming a positive feedback-type enhanced locking effect. In other words, this structure can adaptively increase resistance when there is a tendency to loosen, converting external disturbances into locking force to prevent the nut from loosening, thus achieving active compensation for the attenuation of preload.

[0034] Furthermore, the first washer 31 has a first through hole 311, which extends axially along the first washer 31 and penetrates both its large-diameter and small-diameter ends. The first washer 31 is fitted onto the outer side of the bolt 1 through the first through hole 311, and the first washer 31 and the bolt 1 form a clearance fit. Correspondingly, along the axial direction of the second washer 32, a tapered recess 321 is formed on the end face of the first end of the second washer 32, and the second nut 22 abuts against the end face of the second end of the second washer 32. Similarly, the second washer 32 has a second through hole 322, which extends axially along the second washer 32 and penetrates both ends of the second washer 32. The second washer 32 is fitted onto the outer side of the bolt 1 through the second through hole 322, and the second washer 32 and the bolt 1 form a clearance fit.

[0035] In this embodiment, the diameter of the first through hole 311 and the diameter of the second through hole 322 are consistent; along the axial direction of the bolt 1, the thickness of the first washer 31 and the thickness of the second washer 32 are consistent; along the radial direction of the bolt 1, the outer diameter of the end face of the large-diameter end of the first washer 31 is consistent with the outer diameter of the second washer 32. This increases the stability and consistency of the fitting washer 3 and the overall structure of the anti-loosening assembly. Optionally, the first washer 31 and the second washer 32 can be made of stainless steel, carbon steel, or alloy steel. When carbon steel or alloy steel is used, surface treatments such as electroplating or coating with a non-electrolytic zinc-aluminum coating are required to improve corrosion resistance.

[0036] The following example uses an 8.8 grade M16 carbon steel galvanized surface-treated bolt (the cone angle of the first washer 31 is 24.775°, i.e., ∠A=24.775°). A lateral vibration test is conducted to compare the performance differences between this anti-loosening component and the traditional double-nut anti-loosening structure. The lateral vibration test was conducted according to GB / T10431-2008 "Test Method for Lateral Vibration of Fasteners". Based on the Junker vibration anti-loosening principle, a test platform based on an improved Junker testing machine was used. The lateral vibration load frequency was 12.5Hz, the amplitude was ±1.6mm, and 3000 cycles of vibration were performed. The installation torque of the first nut 21 was 125Nm, and the installation torque of the second nut 22 was 100Nm. The test results of this anti-loosening component are shown in Table 1, and the test results of the traditional double-nut anti-loosening structure are shown in Table 2.

[0037] Table 1

[0038] Table 2

[0039] As can be seen from the parameters in the table, the preload consistency and structural stability of this anti-loosening component (compared to the traditional double-nut anti-loosening structure) have been significantly improved.

[0040] The anti-loosening component in this embodiment also includes a flat washer 4, such as Figure 1 and Figure 3 As shown, when two components need to be connected by this anti-loosening assembly, the flat washer 4 is provided between the second nut 22 and the corresponding component, and the flat washer 4 is also provided between the bolt nut and the corresponding component.

[0041] According to the double-nut anti-loosening assembly of the present invention, the anti-loosening assembly adds a fitting washer 3 to the double-nut anti-loosening structure. The fitting washer 3 includes a first washer 31 and a second washer 32 that can rotate relative to each other, forming a split structure. The first washer 31 and the second washer 32 are fitted together by the first nut 21 and the second nut 22, that is, the first nut 21 abuts against the first washer 31, and the second nut 22 abuts against the second washer 32. Further, the frictional force between the first washer 31 and the second washer 32 is set to F1, the frictional force between the first nut 21 and the first washer 31 is set to F2, and the frictional force between the second nut 22 and the second washer 32 is set to F3, where F1 < F2 and F1 < F3. In this way, when a loosening tendency occurs, the first washer 31 and the second washer 32 of the fitting washer 3 will preferentially rotate relative to each other, thereby avoiding the situation where the first nut 21 and the second nut 22 loosen at the same time, effectively increasing the reliability and stability of the anti-loosening assembly. Furthermore, since the first washer 31 and the second washer 32 can rotate relative to each other and the friction between them is relatively small, discrete and uncontrollable support surface friction will not be introduced during the tightening of the first nut 21 and the second nut 22. As a result, the fluctuation of axial preload is significantly reduced under the same tightening torque, which effectively improves the consistency of preload. Furthermore, since the first washer 31 and the second washer 32 preferentially rotate relative to each other when there is a tendency to loosen, the loosening energy can be consumed, effectively reducing the wear between the nut and bolt thread pair and the contact surface between the nut and the fitting washer 3. As a result, the remaining axial preload at each fastening point of this anti-loosening component can still maintain a high degree of consistency after long-term vibration.

[0042] According to a second aspect of the present invention, a rail transit vehicle is provided, including a car body and a housing device located below the car body. The housing device is correspondingly connected to the car body by a double-nut anti-loosening assembly as described above, thereby effectively preventing the housing device from loosening under long-term vibration conditions.

[0043] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the technical scope disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A double-nut anti-loosening assembly, characterized in that, The double-nut anti-loosening assembly includes: A bolt, wherein a first nut and a second nut are screwed onto the outer side of the bolt; A fitting washer is fitted onto the outer side of the bolt and located between the first nut and the second nut; the fitting washer includes a first washer and a second washer that are rotatable relative to each other; the first nut abuts against the first washer, and the second nut abuts against the second washer; Let F1 be the frictional force between the first washer and the second washer, F2 be the frictional force between the first nut and the first washer, and F3 be the frictional force between the second nut and the second washer, where F1 < F2 and F1 < F3.

2. The double-nut anti-loosening assembly according to claim 1, characterized in that, The first washer is formed into a conical structure, and the second washer is formed into a conical recess that corresponds to and fits the first washer, so that the first washer and the second washer are nested in a corresponding manner.

3. The double-nut anti-loosening assembly according to claim 2, characterized in that, The outer wall of the first washer abuts against the inner wall of the conical recess of the second washer, and the frictional force between the outer wall of the first washer and the inner wall of the conical recess of the second washer is F1.

4. The double-nut anti-loosening assembly according to claim 3, characterized in that, A lubricating layer is formed between the outer side of the first washer and the inner sidewall of the conical recess of the second washer.

5. The double-nut anti-loosening assembly according to claim 2, characterized in that, Along the axial direction of the first washer, the first washer is formed with a large diameter end and a small diameter end, and the first nut abuts against the end face of the large diameter end.

6. The double-nut anti-loosening assembly according to claim 5, characterized in that, The angle between the generatrix of the outer wall of the first washer and the end face of the small diameter end is set as ∠A, and the thread helix angle of the bolt is set as ∠B, where ∠A > ∠B.

7. The double-nut anti-loosening assembly according to claim 5, characterized in that, The first washer has a first through hole, which extends axially along the first washer and passes through the large-diameter end and the small-diameter end; the first washer is fitted onto the outer side of the bolt through the first through hole, and the first washer and the bolt form a clearance fit.

8. The double-nut anti-loosening assembly according to claim 2, characterized in that, Along the axial direction of the second washer, the tapered recess is formed on the end face of the first end of the second washer; the second nut abuts against the end face of the second end of the second washer.

9. The double-nut anti-loosening assembly according to claim 8, characterized in that, The second washer has a second through hole, which extends along the axial direction of the second washer and passes through both ends of the second washer. The second washer is fitted onto the outer side of the bolt through the second through hole, and the second washer and the bolt form a clearance fit.

10. A rail transit vehicle, comprising a car body and a housing located below the car body, characterized in that, The housing equipment is connected to the vehicle body via a double-nut anti-loosening assembly as described in any one of claims 1 to 9.

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