Stress buffer fixing nut and lamp fixing structure

Abstract

The utility model provides a kind of stress buffering fixed nut and lamp fixing structure, belong to automobile lamp technical field.It solves the problem that the reliability of lamp is reduced by a series of problems caused by the vehicle lamp with size length exceeding 300mm.The stress buffering fixed nut includes nut body, the middle part of nut body is coaxially provided with threaded hole, one end of nut body is provided with the elastic buffer body set around threaded hole, and the elastic buffer body is fixed on nut body by connecting structure;The lamp fixing structure includes stress buffering fixed nut and bolt, one end of bolt is fixedly connected with lamp bottom shell, the hole extending along the length direction of lamp bottom shell is formed in the fin of lamp cover, and the bolt is threadedly connected with stress buffering fixed nut after passing through the hole.The elastic buffer body is abutted on the fin of lamp cover when locking, can absorb the internal stress generated due to the difference of thermal expansion coefficient between plastic part and metal fin, reduce the stress concentration of plastic part around bolt, prevent the plastic cracking around bolt fixing point.

Description

Technical Field

[0001] This utility model belongs to the field of automotive lighting technology and relates to a stress-buffered fixing nut and a lighting fixture fixing structure. Background Technology

[0002] In the automotive manufacturing industry, hood flag lights, side flag lights, high-mounted brake lights, front and rear continuous light strips, and ambient lights with dimensions exceeding 300mm in length are typically connected to the vehicle body sheet metal via metal screws and fixing nuts. In practical applications, this fixing method suffers from a series of problems that lead to decreased reliability of the lights due to factors such as material properties, manufacturing processes, and assembly conditions.

[0003] First, due to the significant temperature differences in the automotive environment, especially in winter and summer, there is a substantial difference in the coefficients of thermal expansion between the plastic components that make up the main body of the lamp and the sheet metal that serves as the fixing base. For long lamps, the two materials expand and contract differently along their length when the temperature changes, resulting in significant internal stress at the fixing points. This shear stress caused by the mismatch in thermal expansion and contraction acts on the plastic components over a long period, especially concentrated around the screw holes, which can easily lead to micro-cracks in the plastic components that gradually expand and eventually cause cracking. For lamps with strict sealing requirements, such cracking will directly compromise the integrity of the seal, allowing moisture to enter and causing serious quality problems such as internal circuit short circuits and optical performance failure.

[0004] Secondly, the countersunk hole depth of the engine hood sheet metal parts with countersunk designs inherently has machining errors. Combined with subsequent fluctuations in paint film thickness during the painting process, paint accumulation around the screw holes, and burrs from punching, the cumulative tolerance often exceeds the upper tolerance range of +0.5mm to +1.2mm. When metal nuts are tightened on such uneven surfaces, the plastic parts of the lamp fixture are subjected to continuous tensile stress at the tightening point. This stress concentration can cause the plastic around the screw fixing point to crack, ultimately leading to a risk of water leakage.

[0005] Furthermore, during assembly in the automotive final assembly workshop, some screw hole positions are difficult to access, making it difficult to keep assembly tools (such as electric or pneumatic screwdrivers) perpendicular to the lamp base cover. The lateral force generated during operation, combined with the leverage effect between the screw fixing point and the operator's hand holding the tool, can easily cause the plastic base cover to crack.

[0006] Furthermore, when the metal nut is tightened, its enormous locking reaction force causes localized micro-deformation of the relatively thin sheet metal part being secured. Under the illumination of high-intensity tunnel inspection lights, this micro-deformation manifests as light and shadow distortion and unevenness on the car body surface, affecting the surface quality of the vehicle. Utility Model Content

[0007] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a stress-buffering fixing nut that can provide stress relief.

[0008] A lamp fixing structure that does not deform the plastic parts of the lamp is also proposed.

[0009] The objective of this utility model can be achieved through the following technical solutions:

[0010] A stress-relief fixing nut includes a nut body, a threaded hole coaxially provided in the middle of the nut body, and an elastic buffer body arranged around the threaded hole at one end of the nut body. The elastic buffer body is fixed to the nut body by a connecting structure.

[0011] Because an elastic buffer is provided at one end of the nut body, the elastic buffer can be pressed against the cover sheet metal when tightening, thereby providing stress buffering.

[0012] In the aforementioned stress-buffered fixing nut, the connecting structure includes a connecting sleeve wrapped around the outer annular surface of the nut body, the elastic buffer body is disposed at one end of the connecting sleeve, and the other end of the connecting sleeve is provided with an annular stop flange that presses against the other end of the nut body.

[0013] The connecting sleeve, the annular stop flange, and the elastic buffer are integrally molded and all made of elastic material. The elastic buffer is annular and wraps around the nut body through the elastic buffer, the connecting sleeve, and the annular stop flange to achieve axial and radial positioning, thereby achieving the purpose of fixing the elastic buffer to the nut body.

[0014] In the aforementioned stress-buffered fixing nut, the outer ring surface of the nut body is provided with a plurality of grooves extending along the axial direction of the nut body, and the inner wall of the connecting sleeve is provided with a plurality of protrusions that are matched with the grooves one by one, and the protrusions extend into the corresponding grooves.

[0015] Multiple grooves are evenly distributed along the circumference of the nut body. The grooves penetrate the nut body, and the protrusions extend into the grooves to limit the circumferential position of the connecting sleeve and the nut body, preventing the connecting sleeve from loosening, rotating, or falling off during the locking process.

[0016] In the aforementioned stress-relief fixing nut, the end of the nut body away from the elastic buffer is provided with an annular clearance step, and the annular stop flange presses on the annular clearance step. The inner annular surface of the annular stop flange fits against the side wall of the annular clearance step, and the side of the annular stop flange away from the elastic buffer is flush with the end of the nut body away from the elastic buffer, to prevent the annular stop flange from protruding too high.

[0017] In the aforementioned stress-relief fixing nut, the annular relief step has a recess, and the annular stop edge has a protrusion that mates with the recess, the protrusion extending into the recess. This further restricts the circumferential position of the annular stop edge and the nut body.

[0018] There are multiple recesses, and the number of recesses is equal to the number of grooves. There is one recess between every two adjacent grooves, and the protrusions are arranged in a one-to-one correspondence with the recesses.

[0019] In the aforementioned stress-buffered fixing nut, the elastic buffer body has 2 to 3 annular ribs on the side away from the annular stop edge.

[0020] Two to three concentric annular ribs are arranged to compress and deform during assembly, absorbing manufacturing errors in the installation dimensions of the cover sheet metal, etc.

[0021] In the aforementioned stress-relief fixing nut, a retaining ring is provided on the inner side of the end of the threaded hole away from the elastic buffer body. The retaining ring is not threaded to prevent the nut body from loosening or falling off after long-term use or vibration.

[0022] In the above-mentioned stress-buffered fixing nut, the nut body and the elastic buffer body are formed by secondary injection molding / two-color mold injection molding.

[0023] A lamp fixing structure for fixing the lamp base to the cover sheet metal, including the stress buffer fixing nut and bolt mentioned above. One end of the bolt is fixedly connected to the lamp base. The cover sheet metal has a through hole extending along the length of the lamp base. The bolt passes through the through hole and is threadedly connected to the stress buffer fixing nut.

[0024] Since the through hole extends along the length of the lamp base, when the lamp base deforms in the length direction, it will cause the bolt and stress buffer fixing nut to move together, preventing the plastic (lamp base) around the bolt fixing point from cracking due to stress concentration.

[0025] After being locked in place, the annular rib presses firmly against the sheet metal of the head cover.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] When locked, the elastic buffer body rests against the sheet metal of the lamp cover, absorbing the internal stress caused by the difference in thermal expansion coefficients between the plastic parts and the sheet metal, reducing stress concentration in the plastic parts around the bolt, and preventing cracking of the plastic around the bolt fixing point; the through hole extends along the length of the lamp base, and when the lamp base deforms in the length direction, it will drive the bolt and the stress buffer fixing nut to move together, which can also prevent cracking of the plastic around the bolt fixing point; the nut body and the elastic buffer body are formed by secondary injection molding / two-color mold injection molding, which is simple and low-cost. Attached Figure Description

[0028] Figure 1 This is an installation diagram of the fixing structure of this lamp.

[0029] Figure 2 This is a cross-sectional view of the stress-relief fixing nut provided by this utility model.

[0030] Figure 3 This is a schematic diagram of the structure of the nut body provided by this utility model.

[0031] Figure 4 This is a schematic diagram of the structure of the elastic buffer provided by this utility model.

[0032] In the diagram, 1. Nut body; 11. Threaded hole; 12. Groove; 13. Annular clearance step; 14. Recess; 15. Anti-reverse ring; 2. Elastic buffer; 21. Connecting sleeve; 22. Annular stop edge; 23. Protrusion; 24. Convex body; 25. Annular rib; 3. Bolt; 4. Through hole; a. Lamp base; b. Sheet metal cover. Detailed Implementation

[0033] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0034] like Figure 2 The stress-relief fixing nut shown includes a nut body 1. A threaded hole 11 is coaxially provided in the middle of the nut body 1. A retaining ring 15 is provided at the end of the threaded hole 11. The retaining ring 15 is unthreaded to prevent the nut body 1 from loosening or falling off after long-term use or vibration. In this embodiment, the nut body 1 is made of modified engineering plastics such as PA66+GF30 or PA66+CF30.

[0035] like Figure 2 As shown, one end of the nut body 1 is provided with an elastic buffer 2 surrounding the threaded hole 11. The elastic buffer 2 is annular and is fixed to the nut body 1 by a connecting structure. Figure 2 and Figure 4 As shown, the elastic buffer 2 has 2 to 3 annular ribs 25 on the side away from the annular stop edge 22. The 2 to 3 annular ribs 25 are concentrically arranged, which can be compressed and deformed during assembly to absorb manufacturing errors in the installation dimensions of the cover sheet metal b, etc.

[0036] like Figure 2As shown, the connection structure includes a connecting sleeve 21 wrapped around the outer annular surface of the nut body 1, an elastic buffer 2 disposed at one end of the connecting sleeve 21, and an annular stop 22 pressed against the other end of the nut body 1 at the other end of the connecting sleeve 21. The connecting sleeve 21, the annular stop 22, and the elastic buffer 2 are integrally formed and are all made of elastic materials such as thermoplastic elastic materials such as TPO, TPE, TPU, TPR, and TPV.

[0037] The nut body 1 is enclosed by the elastic buffer 2, the connecting sleeve 21, and the annular stop 22, achieving axial and radial positioning, thereby fixing the elastic buffer 2 onto the nut body 1. Since the elastic buffer 2 is provided at one end of the nut body 1, it can be pressed against the cover sheet metal b during locking, thus providing stress buffering.

[0038] like Figure 3 As shown, the outer ring surface of the nut body 1 is provided with a plurality of grooves 12 extending axially along the nut body 1, such as... Figure 4 As shown, the inner wall of the connecting sleeve 21 has a plurality of protrusions 23 that are configured to mate with the grooves 12 one by one, and the protrusions 23 extend into the corresponding grooves 12.

[0039] Multiple grooves 12 are evenly distributed along the circumference of the nut body 1. The grooves 12 are set through the nut body 1. After the protrusion 23 extends into the groove 12, it can limit the connection sleeve 21 and the nut body 1 in the circumferential position, preventing the connection sleeve 21 from loosening, rotating or falling off during the locking process.

[0040] like Figure 3 As shown, the end of the nut body 1 away from the elastic buffer body 2 is provided with an annular clearance step 13, such as... Figure 2 As shown, the annular stop 22 presses against the annular relief step 13. The inner annular surface of the annular stop 22 is in contact with the side wall of the annular relief step 13, and the side of the annular stop 22 away from the elastic buffer 2 is flush with the end of the nut body 1 away from the elastic buffer 2, so as to prevent the annular stop 22 from protruding 23 too high.

[0041] like Figure 3 As shown, the annular step 13 has a recess 14, such as Figure 4 As shown, the annular stop edge 22 is provided with a protrusion 24 that cooperates with the recess 14, and the protrusion 23 extends into the recess 14, which can further restrict the circumferential position of the annular stop edge 22 and the nut body 1.

[0042] In this embodiment, there are multiple recesses 14, and the number is equal to the number of grooves 12. A recess 14 is provided between every two adjacent grooves 12, and the protrusions 24 are provided in a one-to-one correspondence with the recesses 14.

[0043] After the nut body 1 is injection molded, it is then injection molded again with the elastic buffer body 2 as an insert. Alternatively, it can be directly injection molded using a two-color mold.

[0044] A lamp fixing structure is used to fix the lamp base a onto the cover sheet metal b. It includes a stress-relief fixing nut and a bolt 3. One end of the bolt 3 is fixed to the lamp base a. The cover sheet metal b has a through hole 4 extending along the length of the lamp base a. The bolt 3 passes through the through hole 4 and is threadedly connected to the stress-relief fixing nut.

[0045] Since the through hole 4 extends along the length of the lamp base a, when the lamp base a deforms in the length direction, it will cause the bolt 3 and the stress buffer fixing nut to move together, thus preventing the plastic (lamp base a) around the fixing point of the bolt 3 from cracking due to stress concentration.

[0046] After locking into place, as Figure 1 As shown, the annular rib 25 abuts against the sheet metal b of the hair cover.

[0047] Torque analysis of the M5 nut body 1: The standard locking torque used in the nut design is 0.5~1.5 N·m, and the designed stripping torque of the nut is: 2 N·m ≤ nut stripping torque ≤ 3.5 N·m. When the nut locking torque is too large, the thread will strip first, thereby achieving over-torque protection for parts such as the lamp base a of lamps and other products, preventing cracking due to excessive force, or even causing the entire product to be scrapped.

[0048] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A stress-relief fixing nut, comprising a nut body (1), wherein a threaded hole (11) is coaxially provided in the middle of the nut body (1), characterized in that, One end of the nut body (1) is provided with an elastic buffer (2) surrounding the threaded hole (11), and the elastic buffer (2) is fixed to the nut body (1) by a connecting structure.

2. The stress-relief fixing nut according to claim 1, characterized in that, The connection structure includes a connecting sleeve (21) wrapped around the outer ring surface of the nut body (1), an elastic buffer (2) is provided at one end of the connecting sleeve (21), and the other end of the connecting sleeve (21) is provided with an annular stop flange (22) pressing against the other end of the nut body (1).

3. The stress-relief fixing nut according to claim 2, characterized in that, The outer ring surface of the nut body (1) is provided with a plurality of grooves (12) extending along the axial direction of the nut body (1), and the inner wall of the connecting sleeve (21) has a plurality of protrusions (23) that are matched with the grooves (12) one by one, and the protrusions (23) extend into the corresponding grooves (12).

4. The stress-relief fixing nut according to claim 2, characterized in that, The nut body (1) has an annular relief step (13) at one end away from the elastic buffer (2), and the annular stop edge (22) presses on the annular relief step (13).

5. The stress-relief fixing nut according to claim 4, characterized in that, The annular step (13) has a recess (14), and the annular stop edge (22) has a protrusion (24) that cooperates with the recess (14), and the protrusion (24) extends into the recess (14).

6. The stress-relief fixing nut according to claim 2, characterized in that, The elastic buffer (2) has 2 to 3 annular ribs (25) on the side away from the annular stop edge (22).

7. The stress-relief fixing nut according to claim 1, characterized in that, A backstop ring (15) is provided on the inner side of the end of the threaded hole (11) away from the elastic buffer (2).

8. The stress-relief fixing nut according to claim 1, characterized in that, The nut body (1) and the elastic buffer (2) are formed by secondary injection molding / two-color mold injection molding.

9. A lamp fixing structure for fixing a lamp base shell (a) to a lamp cover sheet metal (b), characterized in that, Includes the stress buffer fixing nut and bolt (3) as described in any one of claims 1-8, one end of the bolt (3) being fixedly connected to the base shell (a) of the lamp, the cover sheet metal (b) having a through hole (4) extending along the length direction of the base shell (a), and the bolt (3) being threadedly connected to the stress buffer fixing nut after passing through the through hole (4).

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