Sound fastener and processing technology thereof

Abstract

The invention relates to a sound fastener and a processing technology, and aims to solve the problem that an existing sound fastener is insufficient in strength and corrosion resistance. The fastener is integrally formed and comprises a threaded section, a transition section with a pin hole and a rod-shaped section, and the rod-shaped section is provided with an auxiliary thread and a cross groove to obtain elasticity. According to the composite fixing structure, multi-dimensional fastening is achieved through thread screwing, elastic clamping, auxiliary thread meshing and pin locking, and thermal expansion and cold contraction displacement can be compensated. The machining comprises the steps of cutting annealing, multi-station cold heading forming, thread rolling for thread manufacturing, pin hole milling, cross groove linear cutting, solution treatment and aging strengthening, and finally passivating treatment. The cold heading improves the strength, the passivation guarantees the corrosion resistance, the tensile strength of the finished product is obviously improved, the salt mist tolerance is good, and the sound box is suitable for household, outdoor and other multi-scene sound box installation.

Description

Technical Field

[0001] This invention belongs to the field of fastener technology, specifically relating to an audio fastener and its processing technology. Background Technology

[0002] Audio fasteners are mechanical connectors used to secure and assemble various components of audio equipment. Their function is to ensure the stability of the audio structure, reduce vibration interference, and prevent loose components from affecting acoustic performance. These fasteners must balance mechanical strength and acoustic compatibility, making them a core and fundamental component in the assembly of an audio system.

[0003] During transportation, relocation, or long-term use, the fasteners of audio equipment must withstand the weight of the enclosure, component loads, and vibration impacts. Their tensile strength must meet the overall load-bearing requirements of the equipment, and their shear strength must resist the lateral shear force caused by vibration to prevent loosening or breakage. Audio equipment is used in various scenarios (home, outdoor performances, humid environments, etc.), so the fasteners must have good corrosion resistance. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, the present invention provides an audio fastener, comprising: The threaded section is a cylinder with threads on its surface, which mates with the threaded mounting hole of the audio equipment to achieve initial fixation; A transition section, wherein a pin hole is provided along its radial direction; The rod-shaped section has an auxiliary thread on its left side and a cross groove on its right side to make it elastic; The threaded section, transition section, and rod-shaped section are connected sequentially and are integrally formed.

[0005] Furthermore, the diameter of the threaded section is larger than that of the transition section, and the diameter of the transition section is larger than that of the rod-shaped section, which is generally stepped and axial. The auxiliary thread has a straight flank and rounded crest and root. The length of the cross groove is 2 / 3 of the length of the rod-shaped section.

[0006] A manufacturing process for audio fasteners includes the following steps: Step 1: Raw material preparation. Cut the bar stock into individual blanks, anneal and pickle the blanks to reduce hardness for easier processing, and remove the surface oxide layer at the same time. Step 2: Cold heading. A multi-station cold heading process is adopted. The billet is fed into the heading die by the feeding mechanism. The first rough heading forms a rough shape with threaded sections and transition sections. The second heading forms a blank with rod-shaped sections. Step 3: Thread section machining. The cold heading blank is clamped on the thread rolling machine fixture, the spacing of the thread rolling wheels is adjusted, and the external thread on the thread section is rolled out. Step 4: Transition section machining. Clamp the workpiece from Step 3 and mill the pin holes on the transition section. Step 5: Machining the rod-shaped section. Turn the outer circle of the rod-shaped section, use a slow wire EDM machine to machine the cross groove, and then machine the auxiliary thread. Step Six: Strengthening treatment. Place the workpiece from Step Five into an aging furnace, hold it at a certain temperature, then quench it in water, hold it at a certain temperature for a period of time, and then air cool it to room temperature. Step 7: Surface treatment, passivating the strengthened workpiece; Step 8: Inspection. Perform dimensional and performance inspections on the finished workpiece.

[0007] Furthermore, the raw material is selected as 304 stainless steel.

[0008] Furthermore, in the cold heading process, the cold heading pressure is controlled at 80~100MPa, and the mold temperature is ≤200℃.

[0009] Furthermore, when machining the external thread on the threaded section, the thread rolling wheel of the thread rolling machine rotates at 80 r / min and the feed rate is 0.5 mm / r.

[0010] Furthermore, in step four, the wire cutting speed is 8m / s and the discharge current is 2A to avoid burrs on the groove. The auxiliary thread is machined on a CNC lathe using a circular arc-shaped thread cutting tool. Through the thread cutting command, the straight section of the tooth flank is cut in layers, while the circular arc edge of the tool completes the circular arc transition between the tooth crest and the tooth root.

[0011] Furthermore, the strengthening treatment specifically involves: placing the workpiece in an aging furnace, holding it at 1050℃ for 30 minutes for solution treatment, then water quenching and cooling; then holding it at 450℃ for 2 hours for aging treatment, and finally air cooling.

[0012] Furthermore, the passivation process in step seven includes: The workpiece is ultrasonically cleaned to remove oil stains, and then pickled with 5% nitric acid solution for 10 minutes. Immerse in a passivation solution at 50°C for 30 minutes, wherein the passivation solution comprises 20% nitric acid and 5% potassium dichromate; Rinse with pure water and then dry with hot air.

[0013] Furthermore, the dimensional inspection in step eight includes using a coordinate measuring machine to inspect the thread pitch diameter, cross groove width, and pin hole position. Performance testing includes tensile shear tests and salt spray tests on the workpiece.

[0014] Compared with the prior art, the present invention has the following outstanding advantages: 1. The audio fastener provided by this invention adopts a composite fixing structure of "threaded connection + elastic snap-fit ​​+ small-segment auxiliary thread engagement", combined with a transition section pin for locking, to achieve multi-dimensional fastening. The threaded segment provides basic tightening force, the grooved rod-shaped segment's elastic snap-fit ​​fits the audio slot, the auxiliary thread of the small segment of the rod engages with the inner wall of the slot to prevent loosening, and the pin further restricts circumferential rotation. The overall tensile and shear load resistance can meet the mechanical requirements of long-term use of the equipment. In addition, the through-groove elasticity of the rod-shaped segment itself allows the rod to absorb the displacement caused by thermal expansion and contraction through slight deformation when the temperature changes, avoiding breakage or loosening caused by rigid stress.

[0015] 2. This invention uses cold heading to replace traditional machining, preserving the continuous flow lines of the metal and avoiding grain fracture caused by cutting, thus improving the tensile and shear strength of the workpiece. Simultaneously, it forms the threaded section, transition section, and rod-shaped section blank in one step, reducing subsequent machining steps. The thread uses a rolling process instead of turning, resulting in a work-hardened layer on the rolled thread surface, increasing hardness and making the thread profile more load-bearing and less prone to stripping. The core function of the strengthening treatment is to eliminate internal stress generated by cold heading and machining processes, stabilizing the dimensional accuracy of the workpiece and preventing deformation or fracture due to stress release during subsequent use, while also improving the tensile and shear strength and toughness of the material. The passivation treatment forms a dense passivation film on the fastener surface, significantly enhancing its corrosion resistance and environmental tolerance, preventing rust in humid and salt spray environments, without affecting the workpiece's appearance and assembly accuracy. These two treatments work together to ensure the mechanical stability and long service life of the fastener. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a speaker fastener according to the present invention; Figure 2 This is a flowchart illustrating the manufacturing process of an audio fastener according to the present invention.

[0017] In the diagram: 1-threaded section, 2-transition section, 21-pin hole, 3-rod-shaped section, 31-auxiliary thread, 32-cross groove. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] like Figure 1 As shown, this invention discloses an audio fastener, comprising: Threaded section 1, which is a cylinder with threads on its surface, engages with the threaded mounting hole of the audio equipment to achieve initial fixation; Transition section 2, wherein a pin hole 21 is provided on the radial side of the transition section 2; The rod-shaped segment 3 has an auxiliary thread 31 on its left side and a cross groove 32 on its right side to make it elastic. The threaded section 1, transition section 2, and rod-shaped section 3 are connected sequentially and are integrally formed.

[0020] Specifically, the diameter of the threaded section 1 is larger than that of the transition section 2, and the diameter of the transition section 2 is larger than that of the rod-shaped section 3, which is generally stepped and axial. The auxiliary thread 31 has a straight flank and rounded top and bottom. The length of the cross groove 32 is 2 / 3 of the length of the rod-shaped segment 3.

[0021] In this embodiment, an audio fastener is used by aligning the threaded section 1 of the fastener with the threaded hole of the audio device (or mounting base) and screwing it in until the transition section 2 fits against the surface of the device. A pin is then inserted into the pin hole 21 of the transition section 2 to lock the fastener to the device body (or base) and prevent the threads from loosening. Then, the rod-shaped section 3 is inserted into the corresponding slot of the audio device, which helps the thread 31 engage with the corresponding structure (such as internal thread / anti-slip teeth) on the inner wall of the slot to further prevent the rod from loosening or falling off. It also helps with positioning, allowing the rod-shaped section to be more accurately fixed in the preset position after it is inserted. The elasticity of the rod is used to lock the interface and complete the assembly. The device employs a composite fastening structure combining threaded connection, elastic snap-fit, and short-segment auxiliary thread engagement, further secured by a transition section 2 with a pin for locking, achieving multi-dimensional fastening. Threaded section 1 provides basic tightening force, the grooved rod-shaped section 3 elastically snaps into the speaker slot, the auxiliary thread 31 on the short section of the rod engages with the inner wall of the slot to prevent loosening, and the pin further restricts circumferential rotation. The overall tensile and shear load resistance meets the mechanical requirements for long-term use of the equipment.

[0022] like Figure 2 As shown, a manufacturing process for an audio fastener includes the following steps: Step 1: Raw material preparation. Cut the bar stock into individual blanks, anneal and pickle the blanks to reduce hardness for easier processing, and remove the surface oxide layer at the same time. Step 2: Cold heading. A multi-station cold heading process is adopted. The billet is fed into the heading die by the feeding mechanism. The first rough heading forms a rough shape with threaded section 1 and transition section 2. The second heading forms a blank with rod-shaped section 3. Step 3: Thread section machining. The cold heading blank is clamped on the thread rolling machine fixture, the spacing of the thread rolling wheels is adjusted, and the external thread on thread section 1 is rolled out. Step 4: Transition section machining. Clamp the workpiece from Step 3 and mill the pin hole 21 on the transition section 2. Step 5: Machining the rod-shaped segment. Turn the outer circle of the rod-shaped segment 3, use a slow wire EDM machine to machine the cross groove 32, and then machine the auxiliary thread 31. Step Six: Strengthening treatment. Place the workpiece from Step Five into an aging furnace, hold it at a certain temperature, then quench it in water, hold it at a certain temperature for a period of time, and then air cool it to room temperature. Step 7: Surface treatment, passivating the strengthened workpiece; Step 8: Inspection. Perform dimensional and performance inspections on the finished workpiece.

[0023] In this embodiment, 304 stainless steel is selected as the material.

[0024] In the cold heading process, the cold heading pressure is controlled at 80~100Mpa to refine the metal grains and improve the tensile and shear strength. The mold temperature is ≤200℃ to avoid overheating and softening of the material. The hardness of the blank after cold heading is ≥HV200.

[0025] Preferably, when machining the external thread on the threaded section 1, the thread rolling machine uses a thread rolling wheel speed of 80 r / min and a feed rate of 0.5 mm / r. After rolling, the thread profile accuracy reaches 6H grade and the surface roughness Ra≤1.6μm, which improves the thread fit sealing performance and enhances environmental resistance.

[0026] Specifically, in step four, the wire cutting speed is 8m / s and the discharge current is 2A to avoid burrs on the groove. The auxiliary thread 31 is machined on a CNC lathe using a circular arc-shaped thread cutting tool. Through thread cutting commands, the straight sections of the tooth flank are cut in layers, while the circular arc edge of the tool completes the circular transition between the tooth crest and root. The straight sections on the tooth flank ensure contact area and positioning accuracy during engagement; the large-radius circular transitions at the tooth crest and root reduce stress concentration and improve wear / impact resistance, making it suitable for high-pressure and high-frequency vibration scenarios.

[0027] Specifically, the strengthening treatment involves: placing the workpiece in an aging furnace and solution-treating it at 1050℃ for 30 minutes, followed by water quenching; then aging it at 450℃ for 2 hours, and finally air-cooling it. The treated workpiece has a hardness ≥ HV250 and a tensile strength ≥ 520 MPa, meeting the tensile and shear requirements.

[0028] Specifically, the passivation process in step seven includes: The workpiece is ultrasonically cleaned to remove oil stains, and then pickled with 5% nitric acid solution for 10 minutes. Immerse in a passivation solution at 50°C for 30 minutes, wherein the passivation solution comprises 20% nitric acid and 5% potassium dichromate; Rinse with pure water and then dry with hot air.

[0029] After passivation treatment, a dense and stable protective film is formed on the surface of the workpiece, thereby preventing the metal from being further corroded.

[0030] In addition, different surface treatment solutions are used for different raw materials: stainless steel passivation, carbon steel Dacromet coating, and aluminum alloy hard anodizing.

[0031] Specifically, the dimensional inspection in step eight includes using a coordinate measuring machine to measure the thread pitch diameter, the width of the cross groove 32, and the position of the pin hole 21; Performance testing includes tensile shear tests and salt spray tests on the workpiece.

[0032] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A type of audio fastener, characterized in that, include: Threaded section (1), the threaded section (1) is a cylinder with threads on its surface, which is engaged with the threaded mounting hole of the audio equipment to achieve initial fixation; Transition section (2), wherein a pin hole (21) is provided on the radial side of the transition section (2); The rod-shaped section (3) has an auxiliary thread (31) on its left side and a cross groove (32) on its right side to make it elastic; The threaded section (1), transition section (2), and rod-shaped section (3) are connected in sequence and are integrally formed.

2. The audio fastener according to claim 1, characterized in that, The diameter of the threaded section (1) is larger than that of the transition section (2), and the diameter of the transition section (2) is larger than that of the rod-shaped section (3). The entire section is in the shape of a stepped shaft. The auxiliary thread (31) has a straight tooth side and a rounded tooth top and bottom. The length of the cross groove (32) is 2 / 3 of the length of the rod-shaped section (3).

3. A processing method for an audio fastener, used to manufacture an audio fastener as described in any one of claims 1-2, characterized in that, Includes the following steps: Step 1: Raw material preparation. Cut the bar stock into individual blanks, anneal and pickle the blanks to reduce hardness for easier processing, and remove the surface oxide layer at the same time. Step 2: Cold heading. A multi-station cold heading process is adopted. The blank is fed into the heading die by the feeding mechanism. The first rough heading is formed into a rough shape with a threaded section (1) and a transition section (2). The second heading is formed into a blank with a rod-shaped section (3). Step 3: Thread section processing. The cold heading blank is clamped on the thread rolling machine fixture, the thread rolling wheel spacing is adjusted, and the external thread on the thread section (1) is rolled out. Step 4: Transition section machining. Clamp the workpiece from step 3 and mill the pin hole (21) on the transition section (2). Step 5: Machining of the rod-shaped segment. The outer circle of the rod-shaped segment (3) is machined out, and a cross groove (32) is machined out using a slow wire EDM machine. Then, the auxiliary thread (31) is machined out. Step Six: Strengthening treatment. Place the workpiece from Step Five into an aging furnace, hold it at a certain temperature, then quench it in water, hold it at a certain temperature for a period of time, and then air cool it to room temperature. Step 7: Surface treatment, passivating the strengthened workpiece; Step 8: Inspection. Perform dimensional and performance inspections on the finished workpiece.

4. The processing technology of an audio fastener according to claim 3, characterized in that, The raw material is selected from 304 stainless steel.

5. The processing technology of an audio fastener according to claim 4, characterized in that, In the cold heading process, the cold heading pressure is controlled at 80~100MPa and the mold temperature is ≤200℃.

6. The processing technology of an audio fastener according to claim 4, characterized in that, When machining the external thread on the threaded section (1), the speed of the thread rolling wheel of the thread rolling machine is 80 r / min and the feed rate is 0.5 mm / r.

7. The processing technology of an audio fastener according to claim 4, characterized in that, In step four, the wire cutting speed is 8m / s and the discharge current is 2A to avoid burrs on the groove. The auxiliary thread (31) is machined on a CNC lathe using a circular arc-shaped thread cutting tool. Through the thread cutting command, the straight section of the tooth side is cut in layers, and the circular arc edge of the tool is used to complete the circular arc transition between the tooth crest and the tooth root.

8. The processing technology of an audio fastener according to claim 4, characterized in that, The strengthening treatment specifically involves: placing the workpiece in an aging furnace, holding it at 1050℃ for 30 minutes for solution treatment, then water quenching and cooling; then holding it at 450℃ for 2 hours for aging treatment, and finally air cooling.

9. The processing technology of an audio fastener according to claim 4, characterized in that, The passivation process in step seven includes: The workpiece is ultrasonically cleaned to remove oil stains, and then pickled with 5% nitric acid solution for 10 minutes. Immerse in a passivation solution at 50°C for 30 minutes, wherein the passivation solution comprises 20% nitric acid and 5% potassium dichromate; Rinse with pure water and then dry with hot air.

10. The processing technology of an audio fastener according to claim 4, characterized in that, Step eight involves dimensional inspection, including measuring the thread pitch diameter, cross groove (32) width, and pin hole (21) position using a coordinate measuring machine. Performance testing includes tensile shear tests and salt spray tests on the workpiece.

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