Self-locking nut assembly with controllable pre-tightening force

Abstract

The invention provides a controllable pre-tightening force self-locking nut assembly which comprises a first gasket, a control gasket, a second gasket and a nut body, the first gasket is used for transmitting axial pressing force of a threaded fastener to a connected piece, the second gasket is located above the first gasket, the control gasket is arranged on the first gasket in a sleeving mode, and the nut body is located above the second gasket. The lower end face of the second gasket makes contact with the upper end face of the control gasket, and the upper end face of the second gasket makes contact with the supporting end face of the nut body. The supporting end face of the nut body extends outwards to form a first boss, the first boss is connected with the first gasket in a meshed mode to form a stop structure, and a closing-in table structure is arranged at the other end of the nut body. The pre-tightening force is controlled through a physical meshing mechanism, additional adjusting tools or detection equipment is not needed, the design mode enables the assembling process to be simpler and more convenient, time and labor cost are saved, dependence on high-precision assembling tools is reduced, and higher stability and looseness resistance are achieved in practical application.

Description

Technical Field

[0001] The present application belongs to the technical field of threaded fastening connectors, and in particular, relates to a self-locking nut assembly with controllable preload force. Background Art

[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, the following methods can be used to control the preload force of fasteners: 1. Fixed-torque installation, that is, using a torque wrench or a force-limiting wrench to select a fixed torque to tighten the nut. This installation method must use installation tools with higher precision; 2. When selecting nuts, use products with a fixed-torque tightening structure such as high-lock nuts. The high-lock nuts have a broken neck groove structure, which will break when a certain torque is reached during the installation process, thereby achieving the purpose of fixed-torque installation.

[0004] However, the preload force value obtained by the above traditional fastening connection methods will also be affected by factors such as friction, lubrication, material type, surface characteristics, etc. According to statistics, the value deviation reaches ±25%; therefore, it is impossible to achieve precise control of the preload force during the installation process of the self-locking nut, which is prone to the risk of nut loosening in a vibration and impact environment. Summary of the invention

[0005] In view of this, the present application aims to propose a controllable pre-tightening force self-locking nut assembly to solve the problem that the pre-tightening force during the installation process of the self-locking nut cannot be accurately controlled.

[0006] To achieve the above purpose, the technical solution of this application is implemented as follows: The present application provides 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 compression force of the threaded fastener to the connected member, and 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 contacts the upper end surface of the control washer, and the upper end surface of the second washer contacts the supporting end surface of the nut body; A first boss is extended outwardly from the supporting end surface of the nut body, and the first boss is meshed and connected with the first washer to form a stop structure, and a closing platform structure is provided at the other end of the nut body; The magnitude of the preload force is controlled according to the fixed distance of the stop structure and the compression displacement of the control washer.

[0007] Furthermore, a first tooth is circumferentially arranged on the bottom end surface of the first boss.

[0008] Further, the first gasket includes a gasket base and a second boss arranged on the gasket base, and the gasket base and the second boss are arranged as one body; The washer base and the second boss are provided with through inner holes for threaded fasteners to pass through.

[0009] Furthermore, a second tooth is circumferentially arranged on the top end surface of the second boss, and the second tooth matches the first tooth.

[0010] Furthermore, the inner hole diameter of the control washer corresponds to the outer diameter of the second boss, so that the control washer is sleeved on the second boss.

[0011] Furthermore, the second gasket is a circular structure, and the diameter of the inner hole thereof corresponds to the outer diameter of the first boss, so that it is sleeved on the first boss.

[0012] Furthermore, the second gasket is made of alloy steel or stainless steel.

[0013] Furthermore, the hardness of the second washer is greater than or equal to the hardness of the nut body, and is much greater than the hardness of the control washer.

[0014] Compared with the prior art, the controllable preload self-locking nut assembly described in the present application has the following beneficial effects: The controllable preload self-locking nut assembly described in the present application realizes the control of the preload through a physical engagement mechanism, without the need for additional adjustment tools or detection equipment. This design makes the assembly process simpler, saves time and labor costs, and reduces the dependence on high-precision assembly tools. It has stronger stability and resistance to loosening in practical applications. The preload control method achieved by this assembly is not affected by factors such as installation tools, friction, lubrication, material type, surface characteristics, etc., and can achieve precise control of the preload during the installation process of the self-locking nut. It can maintain the tightening performance under vibration and impact environments, and effectively avoid the risk of nut loosening due to external factors. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 This is a schematic structural diagram of a self-locking nut assembly with controllable preload force described in an embodiment of the present application; Figure 2 This is a schematic diagram of the nut body structure described in an embodiment of the present application; Figure 3 This is a schematic diagram of the first gasket structure described in an embodiment of the present application; Figure 4 This is a schematic diagram of the relationship between the compression displacement and load of the control gasket described in the embodiment of the present application; Figure 5 A schematic diagram of the installation process of a controllable preload self-locking nut assembly according to an embodiment of the present application; Figure 6 This is a schematic diagram of the completed installation of a controllable preload self-locking nut assembly described in an embodiment of the present application.

[0016] Description of reference numerals: 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 DESCRIPTION

[0017] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0018] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like 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.

[0019] See also Figure 1 As shown, this embodiment provides a controllable preload self-locking nut assembly, comprising a first washer 2, a control washer 3, a second washer 4 and a nut body 1, wherein the first washer 2 is used to transmit the axial pressing force of the threaded fastener 6 to the connected member 5, and the second washer 4 is located above the first washer 2, and is characterized in that: The control washer 3 is sleeved on the first washer 2, the lower end surface of the second washer 4 contacts the upper end surface of the control washer 3, and the upper end surface of the second washer 4 contacts the supporting end surface of the nut body 1; A first boss 11 extends outward from the supporting end surface of the nut body 1, and the first boss 11 is meshed and connected with the first washer 2 to form a stop structure, and a closing platform structure is provided at the other end of the nut body 1; The magnitude of the preload force is controlled according to the fixed distance of the stop structure and the compression displacement of the control washer 3 .

[0020] Specifically, in this embodiment, a stopping structure is provided between the nut body 1 and the first washer 2, so that the self-locking mechanism formed does not require an external torque device to detect the magnitude of the preload force, but controls the magnitude of the preload force by combining the fixed distance between the nut body 1 and the stopping structure of the first washer 2 with the preload force that can be generated after the control washer 3 is compressed.

[0021] Furthermore, the stop structure between the nut body 1 and the first washer 2 is a key design factor of the present application, and 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 force can be determined by controlling the material, heat treatment state, hardness, thickness, etc. of the control washer 3 to determine a suitable control washer 3, so that different preload force levels can be achieved under the same compression amount according to the different control washers 3.

[0022] For example, when the control washer 3 is a steel washer, steel has a higher elastic modulus. Under the same compression, the steel washer usually produces a greater preload force because the steel has a greater rigidity and is not easily deformed. When the control washer 3 is a rubber washer, since the rubber material has a lower elastic modulus, its deformation is greater under the same compression, so the corresponding preload force is smaller. Similarly, when the heat treatment method is different, the hardened steel washer that has been quenched has a higher hardness and less deformation, so it can provide a greater preload force under the same compression.

[0023] Therefore, before selecting a control washer 3 of a certain state, it is necessary to conduct a compression performance test on the control washer 3 of this type, draw a compression force displacement curve, and determine the compression displacement according to the preload requirement. The thickness of the control washer 3 is determined according to the fixed distance between the nut body 1 and the first washer 2 and the compression displacement of the control washer 3. When installing, when the control washer 3 is gradually compressed and reaches the required controlled preload value, the nut and the first washer 2 just reach the meshing point, thereby completing the precise control of the preload.

[0024] The present application has the advantages of simplified design, reduced cost, improved stability and self-locking and anti-loosening. The design of physical engagement between the nut body 1 and the first washer 2 to achieve a predetermined pre-tightening force can also maintain the tightening performance under vibration and impact environments, effectively avoiding the risk of the nut loosening due to external factors.

[0025] In some embodiments, the first gasket 2 includes a gasket base and a second boss 21 disposed on the gasket base, and the gasket base and the second boss 21 are integrally disposed; The washer base and the second boss 21 are provided with through inner holes for the threaded fastener 6 to pass through; The first boss 11 is circumferentially provided with first teeth 12 on the bottom end surface, and the second boss is circumferentially provided with second teeth 22 on the top end surface. The second teeth 22 match the first teeth 12 .

[0026] Specifically, in this embodiment, the structure of the nut body 1 is as follows Figure 2 As shown, the structure of the first gasket 2 is as follows Figure 3 As shown, it has a second boss 21 that is the same as the nut body 1, and the first boss 11 and the second boss 21 are both provided with triangular teeth that match each other, and the two cooperate to form a stopping structure. After the stopping structure is installed, the first washer 2 will engage with the nut body 1 to prevent excessive tightening, and its hardness and material are the same as those of the second washer 4.

[0027] It should be further explained that, in this embodiment, the specific shape and engagement mode of the triangular engagement and 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 force, rather than just preventing loosening.

[0028] The self-locking preload force method in the present application is combined with the specific meshing relationship between the first washer 2, the control washer 3 and the second washer 4. This method of controlling the preload force through self-locking meshing has stronger stability and resistance to loosening in practical applications.

[0029] 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 sleeved on the second boss 21 .

[0030] Specifically, in this embodiment, the control gasket 3 is a circular gasket structure with an inner hole in the center, but its material, heat treatment state, hardness, thickness and size are selected according to the value of the preload to be controlled. Before selecting a control gasket 3 of a certain state, a compression performance test is performed on the control gasket 3 of this type, a compression force-displacement curve is drawn, and the compression displacement is determined according to the preload requirement (the compression load of the gasket is equal to the installation preload), see Figure 4 When the preload control range is 292KN, the control washer 3 dimension A=C+B (see Figure 5 , Figure 6 ), where B is the compression displacement of 0.8mm corresponding to the load of 292KN in the figure below. Its hardness is smaller than that of nut body 1 and other washers.

[0031] In some embodiments, the second gasket 4 is a circular structure, and the inner diameter of the second gasket 4 corresponds to the outer diameter of the first boss 11, so that the second gasket 4 can be sleeved on the first boss 11; 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 is much greater than the hardness of the control washer 3 .

[0032] The actual use of this solution is as follows: according to Figure 5 As shown, each component is sequentially nested into the rear end of the bolt, at which 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; The nut body 1 is twisted and screwed into place. As the supporting end surface of the nut body 1 contacts the second washer 4, the control washer 3 is compressed. During this process, the extrusion force received by the mounting plate gradually increases. After the control washer 3 is compressed, the gap between the nut body 1 and the stop structure of the first washer gradually decreases until they are engaged. At this time, the nut cannot be further tightened due to resistance, and the preload force generated on the mounting plate also reaches the design requirement value, and the installation is completed.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

[0034] The embodiments of the present 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 the present application should be included in the scope of protection of the present 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 compression force of the threaded fastener to the connected member, 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 surface of the second washer contacts the upper end surface of the control washer, and the upper end surface of the second washer contacts the supporting end surface of the nut body; A first boss is extended outwardly from the supporting end surface of the nut body, and the first boss is meshed and connected with the first washer to form a stop structure, and a closing platform structure is provided at the other end of the nut body; The magnitude of the preload force is controlled according to the fixed distance of the stop structure and the compression displacement of the control washer.

2. A controllable preload self-locking nut assembly according to claim 1, characterized in that: The bottom end surface of the first boss is circumferentially provided with first teeth.

3. A controllable preload self-locking nut assembly according to claim 2, characterized in that: The first gasket includes a gasket base and a second boss arranged on the gasket base, and the gasket base and the second boss are arranged in one piece; The washer base and the second boss are provided with through inner holes for threaded fasteners to pass through.

4. A controllable preload self-locking nut assembly according to claim 3, characterized in that: The top end surface of the second boss is circumferentially provided with second teeth, and the second teeth match the first teeth.

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

6. The controllable preload self-locking nut assembly according to claim 2, characterized in that: The second gasket is a circular structure, and the diameter of the inner hole thereof corresponds to the outer diameter of the first boss, so that the second gasket is sleeved on the first boss.

7. The self-locking nut assembly with controllable preload force according to claim 1, characterized in that: The second gasket 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 is much greater than the hardness of the control washer.

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