A controllable pre-tightening force self-locking nut assembly

Abstract

The application provides a controllable pre-tightening force self-locking nut assembly, which comprises a first washer, a control washer, a second washer and a nut body, the first washer is used for transmitting axial compression force of a threaded fastener to a connected part, the second washer is located above the first washer, the control washer is sleeved on the first washer, the lower end surface of the second washer is in contact with the upper end surface of the control washer, and the upper end surface of the second washer is in contact with the supporting end surface of the nut body; the supporting end surface of the nut body outwardly extends a first boss, and the first boss is in meshing connection with the first washer to form a stop structure, and the other end of the nut body is provided with a closed table structure. The application realizes the control of the pre-tightening force through a physical meshing mechanism, does not need additional adjusting tools or detection equipment, the design manner makes the assembly process more simple, saves time and labor cost, and reduces the dependence on high-precision assembly tools, and has stronger stability and anti-loosening performance in actual application.

Description

Technical Field

[0001] This application belongs to the technical field of threaded fasteners, and particularly relates to a controllable preload self-locking nut assembly. Background Technology

[0002] Preload is a key factor in ensuring the reliability of the connection structure. The most common method is to use a torque wrench to measure the tightening torque and indirectly obtain the preload through the conversion relationship between torque and preload.

[0003] Currently, there are several ways to control the preload of fasteners: 1. Constant torque installation, which involves using a torque wrench or force limiter to select a fixed tightening torque to tighten the nut. This method requires high-precision installation tools. 2. When selecting nuts, choose products with a constant torque tightening structure, such as high-lock nuts. High-lock nuts have a neck groove structure, which will break when a certain torque is reached during installation, thus achieving the purpose of constant torque installation.

[0004] However, the preload value obtained by the above traditional fastening connection methods is also affected by factors such as friction, lubrication, material type, and surface characteristics. According to statistics, the value deviation can reach ±25%. Therefore, it is impossible to achieve precise control of the preload during the installation process of self-locking nuts, which can easily lead to the risk of nut loosening in vibration and impact environments. Summary of the Invention

[0005] In view of this, this application aims to propose a controllable preload self-locking nut assembly to solve the problem of the inability to precisely control the preload during the installation process of self-locking nuts.

[0006] To achieve the above objectives, the technical solution of this application is implemented as follows:

[0007] This application provides a controllable preload self-locking nut assembly, including a first washer, a control washer, a second washer, and a nut body. The first washer is used to transmit the axial clamping force of the threaded fastener to the connected parts, and the second washer is located above the first washer.

[0008] The control washer is sleeved on the first washer, the lower end face of the second washer contacts the upper end face of the control washer, and the upper end face of the second washer contacts the supporting end face of the nut body.

[0009] The supporting end of the nut body has a first protrusion extending outward, and the first protrusion engages with the first washer to form a stop structure. The other end of the nut body is provided with a tapering structure.

[0010] The magnitude of the preload is controlled by the fixed distance of the stop structure and the compression displacement of the control washer.

[0011] Furthermore, the bottom end face of the first boss is provided with a first tooth in the circumferential direction.

[0012] Furthermore, the first washer includes a washer base and a second boss disposed on the washer base, wherein the washer base and the second boss are integrally disposed;

[0013] The washer base and the second boss have through holes for threaded fasteners to pass through.

[0014] Furthermore, the top end face of the second boss is provided with a second tooth in the circumferential direction, and the second tooth matches the first tooth.

[0015] Furthermore, the inner diameter of the control washer corresponds to the outer diameter of the second boss, so that the control washer is fitted onto the second boss.

[0016] Furthermore, the second washer has a circular structure, and its inner diameter corresponds to the outer diameter of the first boss, so that it is fitted onto the first boss.

[0017] Furthermore, the second washer is made of alloy steel or stainless steel.

[0018] Furthermore, the hardness of the second washer is greater than or equal to the hardness of the nut body, and much greater than the hardness of the control washer.

[0019] Compared with the prior art, the controllable preload self-locking nut assembly described in this application has the following advantages:

[0020] The controllable preload self-locking nut assembly described in this application achieves preload control through a physical meshing mechanism, eliminating the need for additional adjustment tools or testing equipment. This design simplifies the assembly process, saves time and labor costs, and reduces reliance on high-precision assembly tools. In practical applications, it exhibits stronger stability and resistance to loosening. The preload control method achieved by this assembly is unaffected by installation tools, friction, lubrication, material type, surface characteristics, or other factors. It enables precise control of the preload during the self-locking nut installation process, maintaining fastening performance even under vibration and impact conditions, effectively avoiding the risk of nut loosening due to external factors. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0022] Figure 1 This is a schematic diagram of a controllable preload self-locking nut assembly according to an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the nut body structure described in the embodiments of this application;

[0024] Figure 3 This is a schematic diagram of the first washer structure described in an embodiment of this application;

[0025] Figure 4 This is a schematic diagram illustrating the relationship between the compression displacement of the control washer and the load as described in an embodiment of this application;

[0026] Figure 5 This is a schematic diagram illustrating the installation process of a controllable preload self-locking nut assembly as described in an embodiment of this application.

[0027] Figure 6 This is a schematic diagram showing the completed installation of a controllable preload self-locking nut assembly as described in an embodiment of this application.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1-Nut body; 11-First boss; 12-First tooth; 2-First washer; 21-Second boss; 22-Second tooth; 3-Control washer; 4-Second washer; 5-Connected part; 6-Threaded fastener. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0031] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0032] Please see Figure 1As shown, this embodiment provides a controllable preload self-locking nut assembly, including a first washer 2, a control washer 3, a second washer 4, and a nut body 1. The first washer 2 is used to transmit the axial clamping force of the threaded fastener 6 to the connected part 5. The second washer 4 is located above the first washer 2. The characteristic feature is that:

[0033] The control washer 3 is fitted on the first washer 2, the lower end face of the second washer 4 contacts the upper end face of the control washer 3, and the upper end face of the second washer 4 contacts the support end face of the nut body 1.

[0034] The supporting end of the nut body 1 has a first boss 11 extending outward, and the first boss 11 engages with the first washer 2 to form a stop structure. The other end of the nut body 1 is provided with a constriction platform structure.

[0035] The magnitude of the preload is controlled by the fixed distance of the stop structure and the compression displacement of the control washer 3.

[0036] Specifically, in this embodiment, by setting a stop structure between the nut body 1 and the first washer 2, the self-locking mechanism formed thereby does not require an external torque device to detect the magnitude of the preload. Instead, the magnitude of the preload is controlled by the fixed distance between the nut body 1 and the stop structure of the first washer 2 and the combined preload that can be generated after the control washer 3 is compressed.

[0037] Furthermore, the stop structure between the nut body 1 and the first washer 2 is a key design factor in this application. The fixed distance of the stop structure determines the degree to which the control washer 3 is compressed when the nut is tightened. The magnitude of the preload can be determined by controlling the material, heat treatment state, hardness, and thickness of the control washer 3 to select a suitable control washer 3, thereby achieving different preload levels under the same compression amount based on different control washers 3.

[0038] For example, when control washer 3 is a steel washer, steel has a higher modulus of elasticity. Under the same compression, a steel washer will typically generate a larger preload because steel is more rigid and less prone to deformation. However, when control washer 3 is a rubber washer, rubber has a lower modulus of elasticity. Under the same compression, it deforms more, resulting in a smaller preload. Similarly, when heat treatment methods differ, quenched steel washers have higher hardness and less deformation, thus providing a larger preload under the same compression.

[0039] Therefore, before selecting a control washer 3 for a specific condition, a compression performance test must be conducted on that type of control washer 3 to plot a compression force-displacement curve, and the compression displacement must be determined according to the preload requirement. The thickness of the control washer 3 is determined based on the fixed distance between the nut body 1 and the first washer 2 and the compression displacement of the control washer 3. During installation, as the control washer 3 is gradually compressed to reach the required preload value, the nut and the first washer 2 reach the engagement point, thus achieving precise control of the preload.

[0040] The proposed solution offers advantages such as simplified design, reduced cost, improved stability, and self-locking anti-loosening. Furthermore, the design of using physical engagement between the nut body 1 and the first washer 2 to achieve the predetermined preload can maintain fastening performance even under vibration and impact conditions, effectively avoiding the risk of nut loosening due to external factors.

[0041] In some embodiments, the first washer 2 includes a washer base and a second boss 21 disposed on the washer base, wherein the washer base and the second boss 21 are integrally disposed.

[0042] The washer base and the second boss 21 have through holes for the threaded fastener 6 to pass through.

[0043] The bottom end face of the first boss 11 is provided with a first tooth 12 in the circumferential direction, and the top end face of the second boss is provided with a second tooth 22 in the circumferential direction, and the second tooth 22 matches the first tooth 12.

[0044] Specifically, in this embodiment, the nut body 1 has the following structure: Figure 2 As shown, the structure of the first washer 2 is as follows: Figure 3 As shown, it has a second boss 21 that is the same as the nut body 1. Both the first boss 11 and the second boss 21 are provided with matching triangular teeth. The two work together to form a stop structure. After the stop structure is installed, the first washer 2 will engage with the nut body 1 to prevent excessive tightening. Its hardness and material are the same as the second washer 4.

[0045] It should be further explained that, in this embodiment, the specific shape and engagement method of the triangular meshing, as well as its interaction with the washer, are intended to gradually lock the nut body 1 and the first washer 2 through pressure changes, thereby achieving precise control of the preload, rather than simply preventing loosening.

[0046] The self-locking preload method in this application is combined with a specific meshing relationship between the first washer 2, the control washer 3, and the second washer 4. This method of controlling the preload through self-locking meshing has stronger stability and anti-loosening properties in practical applications.

[0047] In some embodiments, the inner diameter of the control washer 3 corresponds to the outer diameter of the second boss 21, so that the control washer 3 is fitted onto the second boss 21.

[0048] Specifically, in this embodiment, the control washer 3 is a circular washer structure with an inner hole in the center. However, its material, heat treatment state, hardness, and thickness are selected according to the required preload value. Before selecting a control washer 3 in a certain state, a compression performance test is performed on this type of control washer 3, a compression force-displacement curve is plotted, and the compression displacement is determined according to the preload requirement (the compression load of the washer is equal to the installation preload). See [link to documentation]. Figure 4 When the preload control range is 292KN, the control washer size A = C + B (see...). Figure 5 , Figure 6 ), where B is the compressive displacement of 0.8mm corresponding to the 292KN load shown in the figure below. Its hardness is lower than that of the nut body 1 and other washers.

[0049] In some embodiments, the second washer 4 is a circular structure, and its inner diameter corresponds to the outer diameter of the first boss 11, so that it is fitted onto the first boss 11.

[0050] The second washer 4 is made of alloy steel or stainless steel. The hardness of the second washer 4 is greater than or equal to the hardness of the nut body 1, and much greater than the hardness of the control washer 3.

[0051] In practical application, this solution is as follows:

[0052] according to Figure 5 As shown, each component is nested into the bolt tail end in sequence. At this time, the distance between the nut body 1 and the stop structure of the first washer 2 is B, and the thickness of the control washer 3 is A.

[0053] Tighten the nut body 1 in a hexagonal manner to install it. As the supporting end face of the nut body 1 comes into contact with the second washer 4, the control washer 3 will be compressed. During this process, the compressive force received by the mounting plate gradually increases.

[0054] After the control washer 3 is compressed, the gap between the nut body 1 and the stop structure of the first washer gradually narrows until they engage. At this point, the nut cannot be tightened further due to the resistance, and the preload generated on the mounting plate reaches the design requirement value, thus completing the installation.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

[0056] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A controllable preload self-locking nut assembly, comprising a first washer, a control washer, a second washer, and a nut body, wherein the first washer is used to transmit the axial clamping force of the threaded fastener to the connected parts, and the second washer is located above the first washer, characterized in that: The control washer is sleeved on the first washer, the lower end face of the second washer contacts the upper end face of the control washer, and the upper end face of the second washer contacts the supporting end face of the nut body. The supporting end of the nut body has a first protrusion extending outward, and the first protrusion engages with the first washer to form a stop structure. The other end of the nut body is provided with a tapering structure. The magnitude of the preload is controlled by the fixed distance of the stop structure and the compression displacement of the control washer.

2. The controllable preload self-locking nut assembly according to claim 1, characterized in that: The bottom end face of the first boss is provided with a first tooth in the circumferential direction.

3. The controllable preload self-locking nut assembly according to claim 2, characterized in that: The first washer includes a washer base and a second boss disposed on the washer base, wherein the washer base and the second boss are integrally disposed; The washer base and the second boss have through holes for threaded fasteners to pass through.

4. The controllable preload self-locking nut assembly according to claim 3, characterized in that: The top end face of the second boss is provided with a second tooth in the circumferential direction, and the second tooth matches the first tooth.

5. A controllable preload self-locking nut assembly according to claim 3, characterized in that: The inner diameter of the control washer corresponds to the outer diameter of the second boss, so that the control washer is fitted onto the second boss.

6. A controllable preload self-locking nut assembly according to claim 2, characterized in that: The second washer has a circular structure, and its inner diameter corresponds to the outer diameter of the first boss, so that it fits onto the first boss.

7. The controllable preload self-locking nut assembly according to claim 1, characterized in that: The second washer is made of alloy steel or stainless steel.

8. The controllable preload self-locking nut assembly according to claim 1, characterized in that: The hardness of the second washer is greater than or equal to the hardness of the nut body, and much greater than the hardness of the control washer.

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