Balanced thread structure

Abstract

The utility model discloses a balanced thread structure which comprises a base body, a thread and an axial decreasing subtractive material, the thread is formed on the surface of the base body, the axial decreasing subtractive material is at least formed in a screwing area of the thread, and the subtractive quantity of the axial decreasing subtractive material is gradually decreased from the maximum load end of the thread to the minimum load end of the thread in the axial direction of the thread. According to the balanced thread structure, on the premise that basic parameters of standard threads are not changed and axial installation space is not increased, through local axial decreasing and material decreasing, threaded connection load distribution optimization is achieved.

Description

Technical Field

[0001] This utility model relates to the field of threaded connection and fastening technology, specifically to a balanced thread structure. Background Technology

[0002] Threaded connections, a widely used fastening method in mechanical engineering, suffer from uneven load distribution according to the "Mechanical Design Handbook (Sixth Edition)". Typically, the first thread of a traditional threaded connection carries 35±5% of the total load, the first three threads account for over 70% of the total load, and the load on subsequent threads decreases along the thread axis. This phenomenon leads to two core problems: first, a high risk of fatigue failure, with over 50% of thread failures in traditional threaded connections stemming from stress exceeding limits due to load concentration; second, a severely limited number of effective load-bearing turns, with experiments showing that the actual effective load-bearing turns of traditional threads usually do not exceed 5 turns, and threads exceeding this range essentially lose their load-bearing capacity.

[0003] Existing technical solutions all have fundamental flaws in their ability to improve load distribution:

[0004] 1. The suspension nut increases the axial dimension due to the addition of a transition structure, which compromises the compactness of the structure;

[0005] 2. The internal tapered nut is cut with an integral taper, forming a non-standard tooth profile, which has poor compatibility and interchangeability, and requires precise control of the engagement depth during use;

[0006] 3. Wedge nuts have an inclined surface machined on the major diameter of the thread, forming an asymmetrical tooth profile, completely losing compatibility with standard threads;

[0007] 4. Variable pitch threads cannot be assembled with standard fasteners with constant pitch due to the change in pitch;

[0008] 5. Double-helix Tang threads require two nuts with opposite helix directions, making assembly complex and occupying a large amount of axial space.

[0009] In summary, breaking through the technical bottleneck of uneven load distribution in traditional threads without changing standard thread parameters, increasing assembly complexity, or sacrificing space efficiency has become a core issue that the industry urgently needs to address. Utility Model Content

[0010] In view of the above problems, the present invention aims to provide a balanced thread structure that optimizes the load distribution of threaded connections by reducing material in a local axial direction without changing the basic parameters of the standard thread or increasing the axial installation space.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] A balanced thread structure includes a base and a thread, the thread being formed on the surface of the base, and further includes axially decreasing subtractive material, the axially decreasing subtractive material being formed at least in the engagement region of the thread, and the amount of subtractive material decreasing gradually along the thread axis from the end of the thread with the maximum load to the end of the thread with the minimum load.

[0013] To better achieve the above technical solution, the axially decreasing subtractive material is further provided in the crest region of the thread.

[0014] Furthermore, the axially decreasing subtractive material has a V-shaped cross-section in the tooth crest region perpendicular to the thread axis.

[0015] Furthermore, the axially decreasing subtractive material is provided in the tooth flank region of the thread.

[0016] Furthermore, the axially decreasing subtractive material has an isosceles trapezoidal cross-section perpendicular to the thread axis in the tooth side region.

[0017] Furthermore, the axially decreasing subtractive material is provided in the root region of the thread.

[0018] Furthermore, the axially decreasing subtractive material is spaced apart along the helical direction of the thread in the root region of the thread.

[0019] The beneficial effects of this utility model are:

[0020] This invention's balanced thread structure, through axially decreasing subtraction in the thread region, with the amount of subtraction gradually decreasing along the thread axis from the end of maximum load to the end of minimum load, achieves control over the stiffness of the thread region. Areas with larger subtraction have lower local stiffness and correspondingly increased deformation; while areas with smaller subtraction have relatively higher stiffness. The stiffness change caused by axial subtraction alters the load transmission direction, allowing some of the load originally borne by the first thread at the maximum load end to be transferred to the direction of lower load, thus enabling more thread turns to bear more load. This optimizes the load distribution between threaded pairs, with more thread turns participating in load bearing, achieving a multi-turn thread collaborative load-bearing effect. Ultimately, this structure effectively improves the problem of uneven load distribution in threaded connections, making the load distribution along the thread axis more balanced. This invention's balanced thread structure, through the aforementioned axially decreasing subtraction to adjust local stiffness, significantly improves the load balance of threaded connections without changing the original thread geometry. Meanwhile, while retaining the original thread parameters, the load is balanced by axially reducing material, without the need to modify the mating parts, ensuring the interchangeability of the threads and making them easy to use. Attached Figure Description

[0021] Figure 1 This is a three-dimensional schematic diagram of a balanced thread structure according to Embodiment 1 of this utility model;

[0022] Figure 2 yes Figure 1 A sectional view;

[0023] Figure 3 This is a three-dimensional schematic diagram of a balanced thread structure according to Embodiment 2 of this utility model;

[0024] Figure 4 This is a three-dimensional schematic diagram of a balanced thread structure according to Embodiment 3 of this utility model;

[0025] Figure label:

[0026] 10 for the base material, 20 for the thread, and 30 for the axial decreasing material. Detailed Implementation

[0027] The technical solution of this utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. Identical components are indicated by the same reference numerals.

[0028] This utility model discloses a balanced thread structure, including a base 10, a thread 20 and an axially decreasing subtractive material 30. The thread 20 is formed on the surface of the base 10, and the axially decreasing subtractive material 30 is formed at least in the engagement region of the thread 20. The amount of subtractive material 30 decreases gradually along the axial direction of the thread 20 from the end with the maximum load to the end with the minimum load.

[0029] This invention's balanced thread structure, through axially decreasing material reduction in the thread region, with the amount of material reduction gradually decreasing along the thread axis from the end of maximum load to the end of minimum load, achieves control over the stiffness of the thread region. Areas with larger material reduction exhibit lower local stiffness and correspondingly increased deformation, while areas with smaller material reduction have relatively higher stiffness. This stiffness change caused by axially decreasing material reduction alters the direction of thread load transmission, allowing some of the load originally borne by the first thread 20 at the end of maximum load to be transferred to the direction of lower load, thus enabling more threads 20 to bear more load. Consequently, the load distribution between threaded pairs is optimized, with more threads 20 participating in load bearing, achieving a collaborative load-bearing effect. Ultimately, this structure effectively improves the problem of uneven load distribution in threaded connections, making the load distribution along the thread 20 axis more balanced. The balanced thread structure of this invention adjusts the local stiffness by reducing material in the axial direction, thereby improving the load balance of the threaded connection without changing the original thread geometry parameters (such as pitch, thread profile, major / minor diameter, pitch diameter, thread height, etc.).

[0030] Example 1

[0031] like Figure 1 and Figure 2As shown, the axially decreasing subtractive material 30 is provided in the tooth crest region of the thread 20. Specifically, the base 10 is a tubular structure, and the thread 20 is distributed on the inner wall of the base 10 to form an internal thread 20 structure. The axially decreasing subtractive material 30 is in the tooth crest region of the thread 20, and the cross-section perpendicular to the axial direction of the thread 20 has a V-shaped structure.

[0032] As shown below: Taking a single-thread internal thread with a specification of M20×2.5 as an example, the thread 20 has 8 turns of thread 20, and the base material 10 is carbon steel.

[0033] Structure and configuration of axially decreasing subtraction material 30:

[0034] In the crest region of thread 20, an axially decreasing subtractive material 30 is formed along a helical trajectory centered on the axis of thread 20. The cross-section of the axially decreasing subtractive material 30 perpendicular to the axis of thread 20 has a V-shaped structure. The helical direction of the axially decreasing subtractive material 30 is consistent with the helical direction of thread 20.

[0035] In this example, there are 6 axially decreasing subtractive materials 30. The 6 axially decreasing subtractive materials 30 are evenly distributed around the axis of thread 20, that is, the included angle between the center lines of adjacent axially decreasing subtractive materials 30 is 60°.

[0036] The spacing between adjacent axially decreasing subtractive material 30 is set to ≥3P (P is the pitch). The main purpose of this spacing is to avoid a significant increase in local stress caused by the excessive concentration of axially decreasing subtractive material 30.

[0037] Dimensional changes of 30mm reduction in axial thickness:

[0038] Width reduction: Initial width 0.75mm (≤0.3P, where P is the pitch), decreasing by 0.05mm per turn to 0.35mm at the end;

[0039] Depth reduction: Radial depth in the direction perpendicular to the thread axis 20, with the tooth crest as the origin; initial depth 0.63mm (≤0.25P), decreasing by 0.05mm per turn to 0.23mm at the end.

[0040] Detailed features of axially reduced subtractive material 30:

[0041] The bottom of the groove of the axially decreasing subtractive material 30 is provided with a rounded transition with a radius of R = 0.05 mm. This rounded corner helps to alleviate stress concentration.

[0042] In this example, the lead angle of the axially decreasing subtractive 30 helix is ​​preferably 55°.

[0043] In this embodiment, the axial reduction subtraction 30 can be achieved by CNC machine tool cutting along a preset helical trajectory. The amount of material reduction in the axial reduction subtraction 30, i.e., its specific width and depth reduction changes, is achieved by precisely controlling machining parameters such as tool path planning, feed rate, and depth of cut.

[0044] This embodiment presents a balanced thread structure where the cumulative load proportion borne by the first three thread turns (20) is lower than that of the traditional unoptimized structure, measuring ≤66% in this embodiment, while the traditional structure is often greater than 75%. Specifically, the load-bearing proportion of the first thread turn is reduced, measuring approximately 28% in this embodiment, while the traditional structure is often around 35%. The number of thread turns effectively participating in significant load bearing in the threaded pair is increased; in this embodiment, the effective load-bearing number reaches more than 6 turns, while the traditional structure is often in the range of 3-5 turns.

[0045] The above test results demonstrate that, by applying the balanced thread structure of this embodiment, while retaining the original thread 20 geometric parameters, including but not limited to pitch P, thread angle, thread height / middle diameter, etc., the load distribution can be effectively optimized, and the load distribution of the threaded pair can be made more balanced.

[0046] Example 2

[0047] like Figure 3 As shown, the axially decreasing subtractive material 30 is provided in the tooth flank region of the thread 20. Specifically, the base 10 is a rod structure, the thread 20 is distributed on the outer wall of the base 10 to form an external thread 20 structure, and the axially decreasing subtractive material 30 is in the tooth flank region, with a cross-section perpendicular to the axial direction of the thread 20 having an isosceles trapezoidal structure.

[0048] In the embodiment, in the tooth side region of thread 20, an array of axially decreasing subtractive material 30 with decreasing arc length is machined along the spiral trajectory of thread 20. The axially decreasing subtractive material 30 starts from the first turn at the end of the maximum load and is distributed in a circumferential arc length decreasing along the spiral direction. The axially decreasing subtractive material 30 is evenly distributed around the circumference of thread 20 to avoid sudden changes in local stiffness.

[0049] In this embodiment, the axially decreasing subtractive material 30 is formed by die extrusion. Specifically, a protrusion is provided on the die to form the thread 20 side of the axially decreasing subtractive material 30. The required axially decreasing subtractive material 30 is formed in the thread 20 region on the substrate 10 by die extrusion.

[0050] The balanced thread structure in this embodiment also achieves load balance while retaining the original thread 20 parameters.

[0051] Example 3

[0052] like Figure 4As shown, the axially decreasing subtractive material 30 is disposed in the root region of the thread 20. Specifically, the base 10 is a rod structure, and the thread 20 is distributed on the outer wall of the base 10 to form an external thread 20 structure. The axially decreasing subtractive material 30 is disposed at intervals along the helical direction of the thread 20 in the root region of the thread 20.

[0053] In the embodiment, in the root region of thread 20, an array of axially decreasing subtractive material 30 with decreasing arc length is machined along the spiral trajectory of thread 20. The axially decreasing subtractive material 30 starts from the first turn at the end of the maximum load and is distributed in a circular arc length decreasing along the spiral direction. The axially decreasing subtractive material 30 is equidistantly distributed on the spiral path and arranged symmetrically with respect to the axis of thread 20.

[0054] In one embodiment, the axially decreasing subtractive material 30 extends along the adjacent tooth lateral surface of the thread 20 alveolar to intersect and form a shape.

[0055] In this embodiment, the axially decreasing subtractive material 30 is formed by die extrusion. Specifically, a protrusion is provided on the die to form the thread 20 side of the axially decreasing subtractive material 30. The required axially decreasing subtractive material 30 is formed in the thread 20 region on the substrate 10 by die extrusion.

[0056] The balanced thread structure in this embodiment also achieves load balance while retaining the original thread 20 parameters.

[0057] Although this document uses terms such as axial reduction material, material reduction amount, maximum load end, and minimum load end frequently, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of this patent; interpreting them as any additional limitation would contradict the spirit of this patent.

[0058] The technical solution of this utility model has been described in detail above with reference to specific embodiments. The specific embodiments described are used to help understand the concept of this utility model. Derivations and modifications made by those skilled in the art based on the specific embodiments of this utility model also fall within the protection scope of this utility model.

Claims

1. A balanced thread structure, comprising a base (10) and a thread (20), said thread (20) being formed on the surface of the base (10), characterized in that: It also includes axially decreasing material reduction (30), which is formed at least in the engagement region of the thread (20), and the amount of material reduction of the axially decreasing material reduction (30) gradually decreases along the axial direction of the thread (20) from the end of the thread (20) with the maximum load to the end of the thread (20) with the minimum load.

2. The balanced thread structure according to claim 1, characterized in that, The axially decreasing subtractive material (30) is provided in the crest region of the thread (20).

3. The balanced thread structure according to claim 2, characterized in that, The axially decreasing subtractive material (30) has a V-shaped cross-section in the tooth crest region perpendicular to the axial direction of the thread (20).

4. The balanced thread structure according to claim 1, characterized in that, The axially decreasing subtractive material (30) is provided in the tooth flank region of the thread (20).

5. A balanced thread structure according to claim 4, characterized in that, The axially decreasing subtractive material (30) has an isosceles trapezoidal cross-section perpendicular to the axial direction of the thread (20) in the tooth side region.

6. A balanced thread structure according to claim 1, characterized in that, The axially decreasing subtractive material (30) is provided in the root region of the thread (20).

7. A balanced thread structure according to claim 6, characterized in that, The axially decreasing subtractive material (30) is spaced apart along the helical direction of the thread (20) in the root region of the thread (20).

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