Self-locking nut, method for manufacturing same and closing die

Abstract

The application provides a self-locking nut, a manufacturing method thereof and a closing die, and belongs to the technical field of fastener manufacturing. The self-locking nut comprises a nut body and a closing portion connected with the nut body, an internal thread is arranged in the closing portion and the inner hole of the nut body, the axial length of the closing portion is 1-1.5 times of the pitch of the internal thread, and a closing groove which is deformed by axial extrusion is arranged on the axial end face of the closing portion. By shortening the axial length of the closing portion, the weight of the self-locking nut can be reduced, which is beneficial to weight reduction of the connecting structure, and the deformation of the closing portion is realized in the mode of axial extrusion deformation, so that the required anti-loosening purpose is achieved.

Description

Technical Field

[0001] This invention relates to a self-locking nut, its manufacturing method, and a closing mold, belonging to the field of fastener manufacturing technology. Background Technology

[0002] The operating environments for aerospace fasteners are diverse and complex, including high and low temperatures, vibration, alternating stress, shear force, and bending moment. The frictional resistance between the screw pairs is extremely unstable, often decreasing sharply or even disappearing at a moment, losing its self-locking ability. This leads to relative slippage and rotation between the screw pairs, eventually causing the threaded connection to loosen. Therefore, certain anti-loosening methods are typically employed. Currently, commonly used anti-loosening methods include friction anti-loosening, mechanical anti-loosening, and permanent anti-loosening. To avoid complex anti-loosening structures and difficulties in installation and maintenance, friction anti-loosening methods using self-locking nuts are commonly used to achieve the desired effect.

[0003] For example, Chinese invention patent application CN107035753A discloses a shear-resistant dodecagonal self-locking nut for aerospace structures and its manufacturing process. The shear-resistant dodecagonal self-locking nut includes a closing section (i.e., the closing part) and a dodecagonal support platform (i.e., the nut body). The structure of the self-locking nut can also be found elsewhere. Figure 1 As shown, the nut includes a nut body 1 and a constriction portion 2 connected to the nut body 1. Internal threads 3 are provided in the constriction portion 2 and the inner hole of the nut body 1. When manufacturing the self-locking nut, a constriction machine is used to constrict the locking area of ​​the constriction portion 2, flattening it into an elliptical shape. This causes an interference fit when the bolt is screwed into the constriction portion, generating a frictional torque on the surface of the threaded pair, thus preventing loosening.

[0004] The above-mentioned closing method involves radial compression of the closing part 2. In order to ensure the deformation of the locking area and thus achieve the required anti-loosening purpose, the length of the closing part 2 is usually designed to be greater than 2P (P is the pitch of the internal thread 3). However, the excessive length of the closing part 2 is not conducive to the weight reduction of the structure, that is, the single weight of the self-locking nut is relatively high, which is not conducive to achieving weight reduction of the connection structure. Summary of the Invention

[0005] The purpose of this invention is to provide a self-locking nut to solve the problem that the existing self-locking nuts use radial extrusion deformation for the closing part, resulting in a long axial length and thus a high unit weight, which is not conducive to reducing the weight of the connection structure. The purpose of this invention is also to provide a manufacturing method for the self-locking nut and a closing mold for the self-locking nut to solve the above problems.

[0006] To achieve the above objectives, the self-locking nut in this invention adopts the following technical solution:

[0007] A self-locking nut includes a nut body and a constriction portion connected to the nut body. The constriction portion and the inner hole of the nut body are provided with internal threads. The axial length of the constriction portion is 1-1.5 times the pitch of the internal threads. The axial end face of the constriction portion is provided with a constriction groove that is deformed by axial compression.

[0008] The beneficial effects of the above technical solution are as follows: The present invention proposes an improved self-locking nut, wherein the axial length of the closing portion of the self-locking nut is 1-1.5 times the pitch of the internal thread. Compared with the prior art, which is usually more than 2 times the pitch of the internal thread, the axial length of the closing portion of the self-locking nut in the present invention is shorter. On this basis, by providing a closing groove that is deformed by axial compression on the axial end face of the closing portion, the bolt will produce an interference fit when screwed into the closing groove position and generate a friction torque on the surface of the thread pair, thereby playing an anti-loosening role.

[0009] In summary, by shortening the axial length of the closing portion, the present invention can reduce the weight of the self-locking nut, which is beneficial to achieving weight reduction of the connection structure. Furthermore, the axial compression deformation is used to deform the closing portion, thereby achieving the desired anti-loosening purpose.

[0010] Furthermore, the closing groove is an arc-shaped groove that runs radially through the closing portion.

[0011] The beneficial effects of the above technical solution are as follows: the arc groove has a certain arc length, which can increase the deformation length of the closing part, improve the stability of the locking torque, and at the same time ensure that the deformation of the closing part is uniform, preventing cracks from appearing in the junction area between the deformed area and the undeformed area.

[0012] Furthermore, the radius of the arc groove is 1.4-1.6 times the pitch of the internal thread.

[0013] The beneficial effects of the above technical solution are as follows: if the radius of the arc is too small, the deformation is insufficient and the locking torque is small; if the radius of the arc is too large, the deformation is too large and the locking torque is too large, which affects the assembly. The radius of the arc is most suitable to be 1.4-1.6 times the pitch of the internal thread.

[0014] Furthermore, there are at least two closing grooves, each evenly distributed around the circumference.

[0015] The beneficial effects of the above technical solution are: multi-point deformation can increase the locking torque and improve the anti-loosening effect.

[0016] To achieve the above objectives, the manufacturing method of the self-locking nut in this invention adopts the following technical solution:

[0017] A method for manufacturing a self-locking nut includes machining a nut body, a constriction portion, and an internal thread in the constriction portion and the inner hole of the nut body. During machining, the axial length of the constriction portion is ensured to be 1-1.5 times the pitch of the internal thread. Then, the axial end face of the constriction portion is axially compressed by the protrusion on the constriction mold to deform it and form a constriction groove.

[0018] The beneficial effects of the above technical solution are as follows: The present invention improves the existing manufacturing method of self-locking nuts. During the processing, the axial length of the closing part is guaranteed to be 1-1.5 times the pitch of the internal thread. Compared with the existing technology, which is usually more than 2 times the pitch of the internal thread, the axial length of the closing part of the self-locking nut in the present invention is shorter. On this basis, the protrusion on the closing mold is used to axially compress the axial end face of the closing part to deform it and form a closing groove. When the bolt is screwed into the closing groove, an interference fit is generated and a friction torque is generated on the surface of the thread pair to play an anti-loosening role.

[0019] In summary, by shortening the axial length of the closing portion, the present invention can reduce the weight of the self-locking nut, which is beneficial to achieving weight reduction of the connection structure. Furthermore, the axial compression deformation is used to deform the closing portion, thereby achieving the desired anti-loosening purpose.

[0020] Furthermore, at least two localized areas on the axial end face of the constricted portion are subjected to axial compression to form at least two constriction grooves, each constriction groove being evenly distributed around the circumference.

[0021] The beneficial effects of the above technical solution are: multi-point deformation can increase the locking torque and improve the anti-loosening effect.

[0022] To achieve the above objectives, the closing mold for the self-locking nut in this invention adopts the following technical solution:

[0023] A closing mold for a self-locking nut includes a mold body and a protrusion disposed on the end face of the mold body. The mold body is also provided with a connecting structure for fixed connection with the punch of a closing machine, so that the protrusion, driven by the punch, axially presses the axial end face of the closing part of the self-locking nut to be processed and deforms it to form a closing groove.

[0024] The beneficial effects of the above technical solution are as follows: This invention proposes a pioneering self-locking nut end-forming mold. The mold body has a protrusion on its end face and a connecting structure that can be fixedly connected to the punch of the end-forming machine. Under the action of the punch, the protrusion axially presses the axial end face of the end-forming portion of the self-locking nut to be processed, causing deformation and forming an end-forming groove. This results in an interference fit when the bolt is screwed into the end-forming groove, generating a frictional torque on the threaded surface, thus preventing loosening. Because the protrusion axially presses the axial end face of the end-forming portion of the self-locking nut to be processed, the end-forming portion does not need to have an excessively long axial length. Therefore, the axial length of the end-forming portion can be shortened, reducing the weight of the self-locking nut and facilitating weight reduction in the connecting structure.

[0025] Furthermore, the end face of the mold body is circular, and the protrusion is an arc-shaped protrusion extending radially along the end face.

[0026] The beneficial effects of the above technical solution are as follows: the groove extruded by the arc-shaped protrusion is an arc-shaped groove with a certain arc length, which can increase the deformation length of the closing part, improve the stability of the locking torque, and at the same time ensure uniform deformation of the closing part, preventing cracks from appearing in the junction area between the deformed area and the undeformed area.

[0027] Furthermore, the radius of the arc of the raised section is 1.4-1.6 times the pitch of the internal thread of the self-locking nut to be processed.

[0028] The beneficial effects of the above technical solution are as follows: if the radius of the arc is too small, the deformation is insufficient and the locking torque is small; if the radius of the arc is too large, the deformation is too large and the locking torque is too large, which affects the assembly. The radius of the arc is most suitable to be 1.4-1.6 times the pitch of the internal thread.

[0029] Furthermore, at least two protrusions are evenly distributed around the center of the end face of the mold body.

[0030] The beneficial effects of the above technical solution are: multi-point deformation can increase the locking torque and improve the anti-loosening effect. Attached Figure Description

[0031] Figure 1 This is a structural diagram of a self-locking nut in the prior art;

[0032] Figure 2 This is a structural diagram of the self-locking nut in this invention (without closing the end);

[0033] Figure 3 This is a structural diagram of the self-locking nut in this invention (the end has been closed);

[0034] Figure 4 This is a structural diagram of the closing mold for the self-locking nut in this invention.

[0035] Figure 1 In the middle: 1. Nut body; 2. Closure section; 3. Internal thread;

[0036] Figures 2-4 In the middle: 4. Nut body; 5. Closing part; 6. Internal thread; 7. Closing groove; 8. Connecting rod; 9. Mold body; 10. Protrusion; 11. Center hole. Detailed Implementation

[0037] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0038] Example 1 of the self-locking nut in this invention:

[0039] This embodiment improves upon existing self-locking nuts by shortening the axial length of the closing portion, thereby reducing the weight of the self-locking nut and facilitating weight reduction in the connection structure. Furthermore, the axial end face of the closing portion is deformed by axial compression to form a closing groove, achieving the desired anti-loosening purpose.

[0040] Specifically, such as Figure 2 As shown, the self-locking nut includes a nut body 4 and a constriction portion 5 (the constriction portion 5 is the locking area) connected to the nut body 4. Internal threads 6 are machined in the constriction portion 5 and the inner hole of the nut body 1. The axial length of the constriction portion 5 is 1-1.5 times the pitch of the internal thread 6. In this embodiment, it is preferably 1 time. Compared with the prior art, which is usually more than 2 times the pitch of the internal thread, the axial length of the constriction portion of the self-locking nut in this invention is shorter, so the weight of the self-locking nut can be reduced, which is beneficial to the weight reduction of the connection structure.

[0041] Based on this, in order to achieve the deformation of the closing part 5 and achieve the required anti-loosening purpose, such as Figure 3 As shown, the axial end face of the closing part 5 is axially compressed by the protrusions on the closing mold, causing it to deform and form a closing groove 7. The formation of the closing groove 7 causes the internal thread 6 at the corresponding position to deform inward. As a result, when the bolt is screwed into the closing groove 7, an interference fit is formed, and a frictional torque is generated on the surface of the thread pair, which plays a role in preventing loosening. Furthermore, the closing groove 7 is an arc-shaped groove that runs radially through the closing part 5. Since the arc-shaped groove has a certain arc length, it can increase the deformation length of the closing part, improve the stability of the locking torque, and at the same time ensure that the deformation of the closing part is uniform, preventing cracks from appearing in the junction area between the deformed area and the undeformed area.

[0042] Furthermore, the radius of the arc groove is 1.4-1.6 times the pitch of the internal thread 6, preferably 1.5 times in this embodiment. If the radius is too small, the deformation is insufficient and the locking torque is small; if the radius is too large, the deformation is too large and the locking torque is too large, which will affect the assembly. At the same time, there are at least two closing grooves 7, which are evenly distributed around the circumference of each other. In this embodiment, three are preferred to achieve multi-point deformation, which can increase the locking torque and improve the anti-loosening effect, while the deformation points are not too many, which would lead to excessive locking torque and thus affect the assembly.

[0043] In summary, the self-locking nut of the present invention reduces the weight of a single piece by shortening the axial length of the closing portion, which is beneficial for achieving weight reduction in the connection structure. Furthermore, the axial compression deformation of the closing portion achieves the required anti-loosening purpose, ensuring that the locking torque of the nut meets the requirements of GB943, meaning that the locking torque still meets the requirements after 15 cycles of installation.

[0044] In other embodiments of the self-locking nut: the number of closing grooves can be changed, for example, to two or four, or of course, to only one.

[0045] In other embodiments of the self-locking nut: the radius of the arc groove can be changed, for example, to 1.4 times or 1.6 times the pitch of the internal thread. Of course, depending on the actual size of the self-locking nut, the radius of the arc groove can also be less than 1.4 times or greater than 1.6 times the pitch of the internal thread.

[0046] In other embodiments of the self-locking nut, the shape of the closing groove can be changed, for example, it can be a V-shaped groove or a U-shaped groove. Of course, the closing groove can also be a spherical groove. In this case, the closing groove is completely located on the axial end face of the closing part and does not penetrate the closing part radially.

[0047] In other embodiments of the self-locking nut: the axial length of the closing portion can be changed, for example, to 1.5 times the pitch of the internal thread, or it can be 1.2 times or 1.3 times.

[0048] Example 1 of the manufacturing method of the self-locking nut in this invention (hereinafter referred to as the manufacturing method):

[0049] The self-locking nut used in the manufacturing method is the self-locking nut in the above embodiments, such as... Figure 2 As shown, the manufacturing method includes machining the nut body 4, the constriction portion 5, and the internal thread 6 in the inner hole of the constriction portion 5 and the nut body 4. During machining, the axial length of the constriction portion 5 is ensured to be 1-1.5 times the pitch of the internal thread 6, preferably 1 time in this embodiment. Figure 3As shown, the axial end face of the closing part 5 is axially compressed by the protrusions on the closing mold to deform it and form a closing groove 7. The formation of the closing groove 7 causes the internal thread 6 at the corresponding position to deform inward. As a result, when the bolt is screwed into the closing groove 7, an interference fit is formed, and a frictional torque is generated on the surface of the thread pair, which plays a role in preventing loosening. Furthermore, the closing groove 7 is an arc-shaped groove that runs radially through the closing part 5. Since the arc-shaped groove has a certain arc length, it can increase the deformation length of the closing part, improve the stability of the locking torque, and at the same time ensure that the deformation of the closing part is uniform, preventing cracks from appearing in the junction area between the deformed area and the undeformed area.

[0050] Furthermore, the radius of the arc groove is 1.4-1.6 times the pitch of the internal thread 6, preferably 1.5 times in this embodiment. If the radius of the arc is too small, the deformation is insufficient and the locking torque is small; if the radius of the arc is too large, the deformation is too large and the locking torque is too large, which will affect the assembly. At the same time, at least two local axial compressions are applied to the axial end face of the closing part 5 to form at least two closing grooves 7. Each closing groove 7 is evenly distributed around the circumference, preferably three in this embodiment, to achieve multi-point deformation, which can increase the locking torque and improve the anti-loosening effect, while the deformation points are not too many, which would lead to excessive locking torque and thus affect the assembly.

[0051] In summary, the manufacturing method of this invention reduces the weight of the self-locking nut by shortening the axial length of the closing portion, which is beneficial for achieving weight reduction in the connection structure. Furthermore, the deformation of the closing portion is achieved through axial compression deformation, thus achieving the required anti-loosening purpose and ensuring that the locking torque of the nut meets the requirements of GB943, meaning that the locking torque still meets the requirements after 15 cycles of installation.

[0052] In other embodiments of the manufacturing method of the self-locking nut: the number of pressing portions on the axial end face of the closing portion can be changed, thereby changing the number of closing grooves, for example, two or four, or of course, only one.

[0053] Example 1 of the self-locking nut closing mold (hereinafter referred to as closing mold) in this invention:

[0054] The closing mold is used to close the self-locking nut in the above embodiments. The closing mold is also the closing mold used in the above manufacturing method embodiments, specifically as follows: Figure 4 As shown, the closing mold includes a mold body 9 and a protrusion 10 disposed on the end face of the mold body 9. The mold body 9 is also provided with a connecting structure for fixed connection with the punch of the closing machine. In this embodiment, the connecting structure is a connecting rod 8 integrally connected to the mold body 9. The connecting rod 8 is fixedly connected to the punch of the closing machine, so that the closing mold can move under the drive of the punch, thereby causing the protrusion 10 to be axially pressed as... Figure 2The axial end face of the closing portion 5 of the self-locking nut to be processed shown is deformed to form a shape like... Figure 3 The constriction groove 7 shown in the figure.

[0055] Furthermore, the end face of the mold body 9 is circular, and the aforementioned protrusion 10 is an arc-shaped protrusion extending radially along the end face. The closing groove 7 extruded by the arc-shaped protrusion is an arc-shaped groove with a certain arc length, which can increase the deformation length of the closing part, improve the stability of the locking torque, and at the same time ensure uniform deformation of the closing part, preventing cracks from appearing in the junction area between the deformed area and the undeformed area.

[0056] Furthermore, the radius of the arc-shaped protrusion is 1.4-1.6 times the pitch of the internal thread of the self-locking nut to be processed, preferably 1.5 times in this embodiment. If the radius of the arc is too small, the deformation is insufficient and the locking torque is small; if the radius of the arc is too large, the deformation is too large and the locking torque is too large, which will affect the assembly. Meanwhile, if... Figure 4 As shown, a central hole 11 is provided at the center of the end face of the mold body 9, and at least two protrusions 10 are evenly distributed around the central hole 11. In this embodiment, three are preferred, so that multi-point deformation can be achieved, the locking torque can be increased, and the anti-loosening effect can be improved.

[0057] In summary, the closing mold of the present invention compresses the axial end face of the closing part of the self-locking nut to be processed along the axial direction by protrusion, which does not require the closing part to have an excessively long axial length. The axial length of the closing part only needs to be 1-1.5 times the pitch of the internal thread. Therefore, the axial length of the closing part can be shortened, the weight of the self-locking nut can be reduced, and it is beneficial to achieve weight reduction of the connection structure.

[0058] In other embodiments of the self-locking nut closing mold: the number of protrusions can be changed, for example, to two or four, or of course, to just one.

[0059] In other embodiments of the self-locking nut closing mold: the radius of the arc protrusion can be changed, for example, to 1.4 times or 1.6 times the pitch of the internal thread of the self-locking nut to be processed. Of course, depending on the actual size of the self-locking nut, the radius of the arc protrusion can also be less than 1.4 times or greater than 1.6 times the pitch of the internal thread.

[0060] In other embodiments of the self-locking nut closing mold: the shape of the protrusion can be changed, for example, it can be a V-shaped protrusion or a U-shaped protrusion. Of course, the protrusion can also be a spherical protrusion. The size of the spherical protrusion is smaller than the wall thickness of the closing part, so that the closing groove is completely located on the axial end face of the closing part and does not penetrate the closing part radially.

[0061] In other embodiments of the self-locking nut closing mold: the connecting structure on the mold body can also be a connecting hole provided on the mold body.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. A self-locking nut, comprising a nut body (4) and a constriction portion (5) connected to the nut body (4), wherein internal threads (6) are provided in the constriction portion (5) and the inner hole of the nut body (4), characterized in that, The nut body has six external sides, and the constricted part is cylindrical. The outer diameter of the constricted part is smaller than the outer circumferential outline of the nut body. The axial length of the constricted part (5) is 1-1.5 times the pitch of the internal thread (6). A constricted groove (7) is provided on the axial end face of the constricted part (5) and deformed by axial compression. The constricted groove is an arc-shaped groove that runs radially through the constricted part.

2. The self-locking nut according to claim 1, characterized in that, The radius of the arc groove is 1.4-1.6 times the pitch of the internal thread (6).

3. The self-locking nut according to claim 2, characterized in that, The radius of the arc groove is 1.5 times the pitch of the internal thread.

4. The self-locking nut according to any one of claims 1 to 3, characterized in that, There are at least two closing grooves (7), and each closing groove (7) is evenly distributed around the circumference.

5. A method for manufacturing a self-locking nut, comprising machining a nut body (4), a constriction portion (5), and an internal thread (6) in the constriction portion (5) and the inner hole of the nut body (4), characterized in that, The nut body has six external dimensions, and the constricted part is cylindrical. The outer diameter of the constricted part is smaller than the outer circumferential contour of the nut body. During the processing, the axial length of the constricted part (5) is guaranteed to be 1-1.5 times the pitch of the internal thread (6). Then, the axial end face of the constricted part (5) is axially compressed by the protrusion (10) on the constricted mold to deform it and form a constricted groove (7). The protrusion is an arc-shaped protrusion, and the constricted groove is an arc-shaped groove that runs radially through the constricted part.

6. The method for manufacturing a self-locking nut according to claim 5, characterized in that, At least two local axial compressions are applied to the axial end face of the closing part (5) to form at least two closing grooves (7), and each closing groove (7) is evenly distributed around the circumference.

7. A closing mold for a self-locking nut, characterized in that, The mold body (9) includes a mold body (9) and a protrusion (10) on the end face of the mold body (9). The mold body (9) is also provided with a connection structure for fixed connection with the punch of the closing machine, so that the protrusion (10) is driven by the punch to axially press the axial end face of the closing part (5) of the self-locking nut to be processed and deform it to form a closing groove (7). The closing part is cylindrical and is connected to the nut body of the self-locking nut with six outer sides. The outer diameter of the closing part is smaller than the outer circumferential contour of the nut body. The closing part and the inner hole of the nut body are provided with internal threads. The protrusion is an arc protrusion and the closing groove is an arc groove that runs through the closing part radially.

8. The closing mold for the self-locking nut according to claim 7, characterized in that, The end face of the mold body (9) is circular, and the arc protrusion extends radially along the end face.

9. The closing mold for the self-locking nut according to claim 8, characterized in that, The radius of the arc of the arc protrusion is 1.4-1.6 times the pitch of the internal thread (6) of the self-locking nut to be processed.

10. The closing mold for a self-locking nut according to any one of claims 7 to 9, characterized in that, At least two protrusions (10) are evenly distributed around the center of the end face of the mold body (9).

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