Non-equal-pitch double-nut anti-loosening mechanism

Abstract

The invention discloses a non-equal-pitch double-nut anti-loosening mechanism which is suitable for the field of internal thread connection positioning anti-loosening in a complex mechanical environment. The anti-loosening mechanism comprises an adjusting nut, a check nut, a locking gasket and a connecting threaded hole. The locking gasket adopts a special design of a hexagonal boss and a locking piece, and is locked and matched with the adjusting nut and the check nut, so that the double nuts are fixedly connected, and co-rotation angle limitation is realized; under the condition of the same loosening displacement, the non-equal-pitch double nuts rotate the angle barrel to cause motion interference, the axial and circumferential motion amount of the fixedly connected double nuts is limited, reliable looseness prevention of the structure is achieved, and looseness prevention mechanism formula analysis is completed; meanwhile, a design method is provided for the deformation of the locking gasket, the width of a tool withdrawal groove and other structural sizes according to the application situation, and the use scene is expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of servo structures, and in particular relates to a non-equal pitch double-nut anti-loosening mechanism. Background Art

[0002] With the advancement of related technologies in the field of aviation servo, servo actuators are currently developing with the goal of low cost, high carrying capacity, and high reliability as indicators. As an attitude control device, the servo actuator uses a feedback potentiometer preset in the closed cavity of its inner hole as a displacement sensor. During use, it is necessary to ensure that the mechanical zero position of the potentiometer in the closed cavity is in a fixed position to prevent zero deviation. Currently, a threaded adjustment rod is often used to screw along the inner thread of the piston rod to a specific position in the inner cavity to achieve mechanical zero adjustment, and a certain degree of anti-loosening is achieved by tightening the nut, but it cannot achieve absolutely reliable connection. The feedback potentiometer is in a complex mechanical environment such as high impact and high vibration during repeated use. Over time, it is easy to cause the adjustment rod thread to loosen, thereby affecting the normal operation of the actuator and even causing functional failure. Therefore, this field needs to design a positioning and anti-loosening mechanism to ensure the mechanical connection reliability of the potentiometer in a complex mechanical environment, which is particularly critical to the performance of the entire actuator.

[0003] Currently, common methods for preventing threaded nuts from loosening include fuses, thread glue, welding, double nuts, and washers. Due to its structural characteristics, fuses can only be used for external threaded connections and require ample winding space. Thread glue is less effective, as glue particles and debris can introduce unwanted material that affects the performance of individual connections. Welding can achieve reliable connections, but its workability is poor and complex for deep, narrow-aperture threads. Double nuts and washers are simpler to implement and have better workability, but they still carry the risk of loosening and cannot fundamentally solve the problem.

[0004] Patent CN 202111127953.0 discloses a threaded locking structure within a closed cavity. The structure comprises a cover plate, a mating part, a matching part, and an outer shell. The matching part is mounted within the outer shell, which has an inner cavity. The matching part is mounted at one end of the inner cavity, and the cover plate is fixedly connected to the outer shell. The threaded locking structure within the closed cavity completely secures the cover plate by welding. The cover plate compresses and limits the axial movement of the matching part. The hexagonal boss on the cover plate cooperates with the hexagonal hole on the mating part to limit the circumferential movement of the matching part, thereby preventing the threaded connection between the matching part and the matching part from loosening during use. This ensures the reliability of the threaded connection within the closed cavity and ensures that the assembly state of the parts does not change during use. This threaded locking structure is simple and highly reliable, and is suitable for threaded connection structures within closed cavities and for relatively precise parts. This mechanism has a good threaded locking effect, but its implementation requires welding of structural parts, which places high demands on the overall structure's welding processability and welding operation space. Compared with the current solution, the process implementation is more complex and requires higher space requirements.

[0005] Patent 202311541075.6 discloses a locking nut assembly, which includes a nut body and a locking accessory. The nut body has a first internal threaded hole and an outer peripheral surface. The first internal threaded hole penetrates the nut body along the thickness direction of the nut body, and the outer peripheral surface surrounds the first internal threaded hole. The outer periphery of the nut body also has a gap, which penetrates part of the outer peripheral surface and is connected to the first internal threaded hole to separate part of the nut body into a deformation part and a base. The deformation part has a through hole, which penetrates the deformation part along the thickness direction of the nut body. A second internal threaded hole is provided on the side of the base facing the deformation part, and the second internal threaded hole corresponds to the position of the through hole. The locking accessory is passed through the through hole and locked in the second internal threaded hole, and is used to squeeze the deformation part toward the base. This patent adds additional actuators such as a second internal thread and a locking accessory. The structural implementation complexity is higher than that of this solution, and the mechanism analysis shows that the threaded connection of the mechanism still has the possibility of loosening. Summary of the Invention

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide a non-equal pitch double nut anti-loosening mechanism, which realizes the stable connection of the adjustment mechanism from a mechanistic perspective through the motion interference of the two nuts during the loosening process. This thread anti-loosening structure is simple and highly reliable, and can be applied to threaded connection structures in closed cavities and more precise parts.

[0007] The technical solution to achieve the purpose of the present invention is: a non-uniform pitch double-nut anti-loosening mechanism, including an adjusting nut, a locking washer, a tightening nut and a connecting threaded hole; the pitch of the external threads of the tightening nut and the adjusting nut are different, and a hexagonal boss is provided at one end of the locking washer for inserting into the hexagonal through hole of the tightening nut to achieve movement synchronization; a plurality of locking plates are provided at the other end, which are bent and embedded in the adjusting nut array groove to achieve movement synchronization and axial limitation; after rotating the adjusting nut to a specific position of the inner hole, the tightening nut and the locking washer are screwed in together, and after contact, the locking plate is bent to cooperate with the adjusting nut to achieve position locking.

[0008] Furthermore, the adjusting nut serves as a part that is screwed into place, including an external thread of the adjusting nut, an array groove and a through hole of the adjusting nut; the locking washer serves as a circumferential axial locking part of the two nuts, including a hexagonal boss, a locking plate and a washer; the tightening nut serves as a tightening and anti-loosening part, including an external thread of the tightening nut and a hexagonal through hole.

[0009] Furthermore, during the initial zero position adjustment process, the adjusting nut is screwed to the desired position through the external thread of the adjusting nut along the threaded hole of the adjusting nut on one side; the locking gasket is embedded in the hexagonal through-hole of the tightening nut through the hexagonal boss; by tightening the tooling and cooperating with the hexagonal through-hole of the tightening nut, the tightening nut and locking gasket assembly are screwed deeply through the external thread of the tightening nut along the threaded hole of the tightening nut on the other side until the end face of the gasket contacts the left end face of the adjusting nut, at which time the circumferentially arranged locking plates pass through the through-hole of the adjusting nut; fine-tune the tightening nut screwing angle, and when the locking plate is adjusted to be able to bend to the adjacent array groove, the upper part of the bent locking plate is embedded in the array groove to complete the positioning and locking of the entire anti-loosening mechanism.

[0010] Furthermore, the locking washer material is brass or aluminum.

[0011] Furthermore, the number of the array grooves and locking pieces uniformly distributed in the axial direction is N=8.

[0012] Furthermore, during the tightening and adjustment process of the tightening nut, if the right side of the locking washer just contacts the adjusting nut, the locking piece is located in the middle of the two adjacent grooves.

[0013] Furthermore, the axial position and width of the undercut groove need to be pre-designed, and the axial position should satisfy the requirement that after the adjusting nut is positioned, the locking washer is axially located at the center of the undercut groove.

[0014] The present invention also provides a positioning and adjustment method for a non-equal pitch double-nut anti-loosening mechanism, comprising: in the initial zero position adjustment process, the adjusting nut is screwed into the desired position through the external thread of the adjusting nut along the threaded hole of the adjusting nut on one side; the locking gasket is embedded into the hexagonal through-hole of the tightening nut through the hexagonal boss; by tightening the tooling and cooperating with the hexagonal through-hole of the tightening nut, the tightening nut and locking gasket assembly is screwed deeply through the external thread of the tightening nut along the threaded hole of the tightening nut on the other side until the end face of the gasket contacts the left end face of the adjusting nut, at which time the circumferentially arranged locking plates pass through the through-hole of the adjusting nut; fine-tuning the screwing angle of the tightening nut, and when the locking plate is adjusted to be able to bend to the adjacent array groove, the upper part of the bent locking plate is embedded into the array groove to complete the positioning and locking of the entire anti-loosening mechanism.

[0015] Compared with existing technologies, this invention offers significant advantages: a non-uniform-pitch double-nut anti-loosening mechanism for an internal closed cavity, designed to effectively position and securely lock the adjusting nut, is designed to meet the positioning and anti-loosening requirements of high-precision displacement sensors in model projects. Compared to conventional anti-loosening structures, this invention innovates the anti-loosening mechanism, effectively resolving the problem of double-nut loosening. The implementation scheme offers advantages such as ease of operation, simple structure, minimal space requirements, and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the non-equidistant double nut anti-loosening structure of the present invention.

[0017] Figure 2 Schematic diagram of the adjusting nut structure.

[0018] Figure 3 Schematic diagram of the locking gasket structure.

[0019] Figure 4 Schematic diagram of the tightening nut structure.

[0020] Figure 5 This is a schematic diagram of conventional equal-pitch and tightening nuts to prevent loosening.

[0021] Figure 6 This is a schematic diagram of a conventional equal-pitch tightening nut to prevent loosening (opening on one side).

[0022] Figure markings: 1-internal threaded hole, 2-adjusting nut, 3-locking washer, 4-tightening nut, 11-adjusting nut threaded hole, 12-tightening nut threaded hole, 13-threaded backlash, W1-backlash width, W2-adjusting nut thickness, W3-tightening nut thickness, W4-locking washer thickness. DETAILED DESCRIPTION

[0023] The present invention proposes a non-equal pitch double nut anti-loosening mechanism for an inner hole closed cavity, and also provides a positioning adjustment method and an installation method of the structure, thereby realizing a reliable locking and anti-loosening function of the inner hole thread. The non-equal pitch double nut anti-loosening mechanism of the present invention comprises an adjusting nut, a locking washer, a tightening nut and a connecting threaded hole. The outer thread pitch of the tightening nut 4 and the adjusting nut 2 are not equal, and the locking washer 3 is designed to have a hexagonal boss at one end for inserting into the hexagonal through hole of the tightening nut to achieve motion synchronization; eight locking plates are provided at the other end, which are bent and embedded in the adjusting nut array groove to achieve motion synchronization and axial limitation. After rotating the adjusting nut 2 to a specific position in the inner hole, the tightening nut 4 and the locking washer 3 are screwed in together, and after contact, the locking plate is bent to cooperate with the adjusting nut to achieve position locking. This anti-loosening structure can solve the problem of loosening of the inner hole nut from a mechanism point of view, and the structural form is simple and easy to implement.

[0024] The present invention is further described in detail below with reference to the accompanying drawings.

[0025] The invention provides a non-uniform pitch double-nut anti-loosening mechanism for an inner hole closed cavity. Figure 1 The main structure of the anti-loosening structure of the present invention is shown, which comprises an internal threaded hole 1, an adjusting nut 2, a locking washer 3, and a tightening nut 4. Figure 4 In order to more clearly illustrate the embodiment of the present invention and the anti-loosening mechanism, the following will be described in conjunction with the accompanying drawings.

[0026] The internal threaded hole 1 is an integral external structure. In this case, it is the inner hole of the piston rod. In other fields, it can be adjusted according to the use environment. The threads of the internal threaded hole are divided into two types along the two sides of the undercut 13: the tightening nut threaded hole 11 and the adjusting nut threaded hole 12. Both threaded holes are single-threaded, with the same nominal thread diameter and pitches of P1 and P2 respectively.

[0027] The adjusting nut 2 is a screw-in part, and its detailed structure is shown as follows: Figure 2 As shown, it includes an external thread 21 of an adjusting nut, an array groove 22, and a through hole 23 of an adjusting nut;

[0028] The locking washer 3 is used as a circumferential axial locking part for the two nuts. The detailed structure is shown in the figure below. Figure 3 As shown, it includes a hexagonal boss 31, a locking piece 32, and a gasket 33;

[0029] The tightening nut 4 is used as a tightening and anti-loosening part, and the detailed structure is shown as follows Figure 4 As shown, it includes a tightening nut external thread 41 and a hexagonal through hole 42.

[0030] The embodiment of the present invention is as follows: During the initial zero position adjustment process, the adjusting nut 2 is screwed into the desired position along the right adjusting nut threaded hole 11 through the adjusting nut external thread 21. The desired position refers to the zero position of the potentiometer in this case. The locking washer 3 is inserted into the hexagonal through-hole 42 of the tightening nut 4 through the hexagonal boss 31. By tightening the fixture and cooperating with the hexagonal through-hole 42 of the tightening nut, the tightening nut 4 and locking washer 3 assembly is screwed into the left tightening nut threaded hole 12 through the tightening nut external thread 41 until the end face of the washer 33 contacts the left end face of the adjusting nut 2. At this time, the circumferentially arranged locking plates 32 pass through the adjusting nut through-hole 23. The screwing angle of the tightening nut 4 is fine-tuned. When the locking plates 32 are adjusted to be able to bend vertically to the adjacent array groove 22, the upper portion of the bent locking plates is inserted into the groove, completing the positioning and locking of the entire anti-loosening mechanism. The vertical bending refers to the locking plates entering the array groove after bending. Ideally, the bending angle is 90°.

[0031] The anti-loosening mechanism of the present invention is as follows: Under mechanical environments such as high vibration and impact, when a single machine works at high frequency for a long time, the conventional equal-pitch double-nut anti-loosening mechanism is prone to loosening due to the lack of fixed connection. If a fixing method such as a stop washer, a bent locking piece, or a butt pin is added, it is essentially equivalent to a composite nut with superimposed thickness, and there is still a risk of loosening, such as Figure 5 As shown. In the present invention, the circumferential locking piece 32 of the locking washer and the hexagonal boss 31 cooperate with the adjusting nut array groove 22 and the tightening nut hexagonal through hole 42 respectively to achieve the fixed connection of the entire mechanism. If it is assumed that when the entire composite nut is initially loosened, the adjusting nut and the tightening nut will jointly undergo a small axial displacement L. At this time, because the pitches of the two are P1 and P2 respectively, according to formula (1), the corresponding nut rotation angles θ are not equal. However, at this time, the three locking pieces 32 in the mechanism cooperate with the array groove 22, and the hexagonal boss 31 cooperates with the hexagonal through hole 42, forming an angular rotation interference between the two nuts, so that they cannot undergo relative angular displacement, forming a self-locking structure, and realizing the axial positioning and anti-loosening of the entire mechanism.

[0032]

[0033] In particular, if the positioning accuracy of the adjusting nut is required to be high, the locking washer should be made of a low-strength and volatile material such as brass or aluminum to achieve the interference deformation generated when the locking plate and the array groove are aligned. In the present invention, the number of axially uniformly distributed array grooves and locking plates is N=8. During the tightening and adjustment process of the tightening nut, if the right side of the locking washer just contacts the adjusting nut, the locking plate is located in the middle of the two adjacent grooves. In this state, the maximum deformation of the locking washer positioned by the anti-loosening mechanism needs to meet m=1 / 2*P1 / N, where P1 is the pitch of the adjusting nut.

[0034] In particular, the adjusting nut is not only a single form as shown in the figure, but can be extended to any structural form with the functions of an external nut and a locking groove, and connected with components such as springs and sensors to achieve reliable positioning and anti-loosening of more precise parts in a closed cavity.

[0035] In particular, the axial position and width of the undercut 13 must be pre-designed. The optimal axial position is achieved when the locking washer is axially centered after the nut is adjusted. The undercut width W1 must be greater than the locking washer thickness W4 + n1P1 + n2P2, and less than the nut thicknesses W2 and W3. The optimal ratios for n1 and n2 are 1 to 2.

[0036] In particular, the present invention is based on actual usage scenarios, and the demonstration case is the internal thread with two-sided openings. For the usage scenarios of single-sided openings such as countersunk holes, stepped thread holes with "unequal pitch + unequal thread nominal diameter" can be used to achieve mechanism anti-loosening, such as Figure 6 shown.

[0037] In particular, the number N of the array grooves and locking pieces uniformly distributed in the axial direction in the present invention is 8, which can be adaptively designed according to the requirements of positioning accuracy, processing technology and operating space in practice.

[0038] This paper proposes a novel anti-loosening mechanism for double nuts with unequal pitches for use in closed inner cavities. It innovatively designs a "self-locking mechanism due to angular interference when nuts with different pitches move together." It also conducts a theoretical analysis of the mechanism's self-locking and anti-loosening mechanism, designs a structural form for typical usage scenarios, and provides an implementation plan.

[0039] The present invention quantitatively analyzes the design of structural component dimensions such as the width of the inner hole undercut and the thickness deformation of the locking gasket;

[0040] The locking gasket in the present invention innovatively adopts the structure of "hexagonal boss + locking plate", and realizes the tightening and limiting of double nuts through the above two local designs.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of improvement of the present invention.

Claims

1. A non-equal pitch double nut anti-loosening mechanism, characterized in that: The invention comprises an adjusting nut (2), a locking washer (3), a tightening nut (4) and a connecting threaded hole; the outer thread pitches of the tightening nut (4) and the adjusting nut (2) are different; a hexagonal boss is provided at one end of the locking washer (3) for inserting into the hexagonal through hole of the tightening nut to achieve motion synchronization; a plurality of locking pieces are provided at the other end, which are bent and embedded into the array grooves of the adjusting nut to achieve motion synchronization and axial limitation; after the adjusting nut (2) is rotated to a specific position of the inner hole, the tightening nut (4) and the locking washer (3) are screwed in together, and after contact, the locking piece is bent to cooperate with the adjusting nut (2) to achieve position locking.

2. The non-equal pitch double nut anti-loosening mechanism according to claim 1, characterized in that: The adjusting nut (2) serves as a screw-in-place part, comprising an adjusting nut external thread (21), an array groove (22) and an adjusting nut through hole (23); the locking washer (3) serves as a circumferential axial locking part for the two nuts, comprising a hexagonal boss (31), a locking plate (32) and a washer (33); the tightening nut (4) serves as a tightening and anti-loosening part, comprising a tightening nut external thread (41) and a hexagonal through hole (42).

3. The non-equal pitch double nut anti-loosening mechanism according to claim 2, characterized in that: During the initial zero adjustment process, the adjusting nut (2) is screwed into the desired position along the adjusting nut threaded hole (11) on one side through the adjusting nut external thread (21); the locking washer (3) is embedded into the hexagonal through hole (42) of the tightening nut through the hexagonal boss (31); by tightening the tooling and cooperating with the hexagonal through hole (42) of the tightening nut, the tightening nut and the locking washer assembly are screwed deeply through the tightening nut external thread (41) along the tightening nut threaded hole (12) on the other side until the end face of the washer (33) contacts the left end face of the adjusting nut, at which time the circumferentially arranged locking pieces (32) pass through the adjusting nut through hole (23); the tightening nut screwing angle is fine-tuned, and when the locking piece (32) is adjusted to be able to bend to the adjacent array groove (22), the upper part of the bent locking piece is embedded in the array groove, completing the positioning and locking of the entire anti-loosening mechanism.

4. The non-equal pitch double nut anti-loosening mechanism according to claim 1, characterized in that: The locking washer material is brass or aluminum.

5. The non-equal pitch double nut anti-loosening mechanism according to claim 1, characterized in that: The number of axially evenly distributed array grooves and locking pieces is N=8.

6. The non-equal pitch double nut anti-loosening mechanism according to claim 1, characterized in that: During the tightening and adjustment process of the tightening nut, if the right side of the locking washer just contacts the adjusting nut, the locking plate is located in the middle of the two adjacent grooves.

7. The non-equal pitch double nut anti-loosening mechanism according to claim 1, characterized in that: The axial position and width of the undercut groove (13) need to be pre-designed. The axial position should be such that after the adjusting nut is positioned, the locking washer is axially located at the center of the undercut groove.

8. A positioning and adjustment method for the non-equal pitch double nut anti-loosening mechanism according to claim 1, characterized in that: include: During the initial zero adjustment process, the adjusting nut (2) is screwed into a specific position along the adjusting nut threaded hole (11) on one side through the adjusting nut external thread (21); the locking washer (3) is embedded into the hexagonal through hole (42) of the tightening nut through the hexagonal boss (31); by tightening the tool and cooperating with the hexagonal through hole (42) of the tightening nut, the tightening nut and the locking washer assembly are screwed deeply along the tightening nut threaded hole (12) on the other side through the tightening nut external thread (41) until the end face of the washer (33) contacts the left end face of the adjusting nut, at which time the circumferentially arranged locking pieces (32) pass through the adjusting nut through hole (23); the tightening nut screwing angle is fine-tuned, and when the locking piece (32) is adjusted to be able to bend to the adjacent array groove (22), the upper part of the bent locking piece is embedded in the array groove, completing the positioning and locking of the entire anti-loosening mechanism.

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