A manufacturing process for a spring ejector pin

Abstract

The application discloses a manufacturing process method of a spring thimble, and belongs to the technical field of thimble manufacturing. The method provides a cylindrical needle tube with an open end and a closed end. First, the inner wall of the needle tube is cleaned and degreased, and the inner wall is subjected to sand blasting treatment. One end of a spiral spring is fixedly connected with the tail of a needle shaft, and the spring axis is confirmed to coincide with the needle shaft axis. A coaxial pressing core rod is used to push a radial constraint ring sleeve into the needle tube from the open end of the needle tube, and the radial constraint ring sleeve is axially pushed to a preset position on the inner wall of the needle tube. The needle shaft and the spiral spring are installed with the tail end of the needle shaft downward. Through a reserved small hole outside the closed end of the needle tube, conductive glue is injected to the bottom of the needle tube, and the glue solution contacts the other end of the spiral spring. After the conductive glue is solidified, the spiral spring is fixedly connected with the bottom of the needle tube. The application can avoid plastic bending or eccentric wear failure of the spring after long-term use, and further cause the problems of sudden increase of charging contact resistance or open circuit.

Description

Technical Field

[0001] This invention belongs to the field of ejector pin manufacturing technology, specifically relating to a manufacturing process method for a spring ejector pin. Background Technology

[0002] During use, the spring pin has a necessary gap between its outer diameter and the inner diameter of the needle tube because the outer diameter of the spring is smaller than the inner diameter of the needle tube. Due to factors such as the angle at which the earphones are placed, the needle shaft is subjected to a lateral force the moment the Bluetooth earphones are placed in the charging case. This lateral force is transmitted to the end of the spring through the tail of the needle shaft. Under long-term action, the spring will undergo non-axial lateral displacement and bending deformation within the needle tube, resulting in severe unilateral friction between the spring coil and the inner wall of the needle tube, and even permanent bending of the middle of the spring. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a manufacturing process for a spring pin, which can avoid the spring from plastic bending or eccentric wear failure after long-term use, thereby causing a sudden increase in charging contact resistance or open circuit.

[0004] To achieve the above objectives, the present invention provides the following technical solution: This invention discloses a manufacturing process for a spring-loaded ejector pin. The spring-loaded ejector pin includes a needle shaft, a needle tube, a helical spring, and a radial constraint ring. The needle tube is a cylindrical shell with one end open and the other end closed. The needle shaft is slidably mounted on the open end of the needle tube. The helical spring is placed inside the needle tube, with its two ends connected to the bottom of the needle tube and the needle shaft, respectively. The radial constraint ring is disposed within a radially spaced gap between the helical spring and the needle tube. The manufacturing process includes the following steps: Step (1), needle installation: Provide a cylindrical needle tube with one end open and the other end closed. First, clean and degrease the inner wall of the needle tube, and then sandblast the inner wall. This area is used for subsequent installation of the radial constraint ring. Step (2): Pre-connect the helical spring to the needle shaft. Select a helical spring with an outer diameter smaller than the inner diameter of the radial constraint ring. Fix one end of the helical spring to the tail of the needle shaft and confirm that the spring axis coincides with the needle shaft axis. Step (3), Radial constraint ring positioning and fixing: Use a coaxial press-fit mandrel to push the radial constraint ring inward from the needle tube opening end, and push it axially to the preset position on the inner wall of the needle tube; Step (4): The entire assembly is installed into the needle tube. The needle shaft and the helical spring are installed with the tail end of the needle shaft facing down. The needle shaft is vertically inserted into the needle tube from the open end. The helical spring is inserted from the center of the radial constraint ring. During the insertion process, the outer wall of the radial constraint ring contacts the sandblasted rough area of ​​the inner wall of the needle tube. A certain radial gap is maintained between the inner side of the radial constraint ring and the spring, allowing the spring to extend and retract freely but preventing it from bending radially. Step (5): The spring is connected to the bottom of the needle tube. Conductive adhesive is injected into the bottom of the needle tube through the reserved small hole on the outside of the closed end of the needle tube. The adhesive contacts the other end of the spiral spring. After the conductive adhesive cures, the spring is fixedly connected to the bottom of the needle tube.

[0005] Furthermore, the spring ejector pin also includes an upper limit ring and a lower limit ring. The upper limit ring and the lower limit ring are coaxially fixed inside the needle tube. The upper limit ring and the lower limit ring are used to limit the two ends of the radial constraint ring sleeve respectively. In step (3), after the radial constraint ring sleeve is pushed inward from the opening end of the needle tube using a coaxial pressing mandrel, the radial constraint ring sleeve is axially pushed to contact the lower limit ring before the upper limit ring is installed.

[0006] Furthermore, the needle tube includes an upper tube, a lower tube, and a sleeve. The upper tube is coaxially mounted on the upper side of the lower tube, and the sleeve is coaxially positioned on the outside of the upper and lower tubes to connect them. By rotating the sleeve, the interval between the upper and lower tubes can be changed.

[0007] Furthermore, the upper limit ring and the lower limit ring are threaded to the inner sides of the upper tube and the lower tube, respectively. Before installing the radial constraint ring sleeve, after determining the length of the needle tube, first rotate the lower limit ring inside the lower tube to make it axially displace to the preset position, then install the radial constraint ring sleeve, and then install the upper limit ring. Rotate the upper limit ring to make it axially displace to the preset position to limit the radial constraint ring sleeve.

[0008] Furthermore, the spring ejector pin also includes a top limiting ring. The inner diameter of the top limiting ring is smaller than the inner diameter of the needle shaft boss. After the entire assembly is installed into the needle tube, the top limiting ring can be detachably connected to the opening of the needle tube to limit the needle shaft.

[0009] Furthermore, in step (2), the specific method for fixing one end of the helical spring to the tail of the needle shaft is as follows: a cross-shaped or star-shaped radial groove is pre-machined at the tail of the needle shaft, and a blind hole is opened in the center of the groove; after the end of the helical spring is softened by high-temperature tempering, a pulse current is passed through it, so that the inner wall of the blind hole and the helical spring undergo local melting and bonding.

[0010] The beneficial effects of this invention are as follows: This invention discloses a manufacturing process for a spring ejector pin, which follows a progressive logic from the inside out and from components to assembly. Each step includes dedicated coaxial tools and heating / vibration aids to prevent misalignment or pre-compression damage to the spring during assembly. This significantly improves the axial concentricity, conductivity reliability, and radial impact resistance of the spring ejector pin, preventing plastic bending or eccentric wear failure after long-term use, which could lead to a sudden increase in charging contact resistance or open circuit. Attached Figure Description

[0011] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration: Figure 1 This is a schematic diagram of the structure of the spring ejector pin of the present invention; The following are the markings in the attached diagram: needle shaft 1, needle tube 2, helical spring 3, radial constraint ring 4, upper limit ring 5, lower limit ring 6, upper tube 7, lower tube 8, sleeve 9, top limit ring 10. Detailed Implementation

[0012] This invention discloses a manufacturing process for a spring ejector pin, wherein, as shown in the following... Figure 1 As shown, the spring-loaded ejector pin includes a needle shaft 1, a needle tube 2, a helical spring 3, and a radial constraint ring 4. The needle tube 2 is a cylindrical shell with one end open and the other end closed, with the opening facing upwards during installation. The needle shaft 1 is slidably fitted onto the open end of the needle tube 2. The bottom of the needle shaft 1 has a boss, which serves as a limit to prevent the needle shaft 1 from dislodging from the opening of the needle tube 2. The helical spring 3 is placed inside the needle tube 2, with its two ends connected to the bottom of the needle tube 2 and the needle shaft 1, respectively. The helical spring 3 provides outward elastic support to the needle shaft 1. The radial constraint ring 4 is positioned within the radially spaced gap between the helical spring 3 and the needle tube 2. The manufacturing process includes the following steps: Step (1), needle tube 2 installation, a cylindrical needle tube 2 with one end open and the other end closed is provided. The needle tube 2 has a straight cylindrical inner wall. Before installation, the inner wall of the needle tube 2 is cleaned and degreased, and its inner wall is sandblasted. This not only removes residual oil and micro burrs from the processing, but also increases its strength. This area is used for subsequent installation of radial constraint ring 4. Step (2): Pre-connect the helical spring 3 to the needle shaft 1. Select a helical spring 3 with an outer diameter smaller than the inner diameter of the radial constraint ring 4. Fix one end of the helical spring 3 to the tail of the needle shaft 1. Confirm that the spring axis coincides with the needle shaft 1 axis to reduce the possibility of subsequent bending. Step (3): Positioning and fixing of radial constraint ring 4. Use coaxial press-fit mandrel to push radial constraint ring 4 inward from the opening end of needle tube 2 and push it axially to the preset position on the inner wall of needle tube 2. Step (4): The entire assembly is installed into the needle tube 2. The needle shaft 1 and the helical spring 3 are installed with the tail end of the needle shaft 1 facing down. The needle shaft 1 is vertically inserted into the needle tube 2 from the open end. The helical spring 3 is inserted from the center of the radial constraint ring 4. During the insertion process, the outer wall of the radial constraint ring 4 contacts the sandblasted rough area of ​​the inner wall of the needle tube 2. A certain radial gap is maintained between the inner side of the radial constraint ring 4 and the spring, allowing the spring to extend and retract freely but preventing it from bending radially. Using the above method, it is easy to install and avoids the needle shaft 1 and the helical spring 3 from separating.

[0013] Step (5): The spring is connected to the bottom of the needle tube 2. Through the reserved small hole on the outside of the closed end of the needle tube 2, conductive glue is injected to the bottom of the needle tube 2. The glue contacts the other end of the spiral spring 3. After the conductive glue is cured, the spring and the bottom of the needle tube 2 are fixedly connected. The connection between the spring and the bottom of the needle tube 2 can be realized, which is convenient.

[0014] In this embodiment, the spring ejector pin also includes an upper limit ring 5 and a lower limit ring 6. The upper limit ring 5 and the lower limit ring 6 are coaxially fixed inside the needle tube 2. The upper limit ring 5 and the lower limit ring 6 are used to limit the two ends of the radial constraint ring sleeve 4 respectively. In step (3), after the coaxial pressing mandrel pushes the radial constraint ring sleeve 4 inward from the open end of the needle tube 2, the radial constraint ring sleeve 4 is axially pushed to contact the lower limit ring 6 before the upper limit ring 5 is installed. When the ejector pin undergoes a large number of compression cycles, the vibration and the axial recoil force of the spring may cause the ring sleeve to gradually deviate from the ideal position, resulting in a weakening or even failure of the constraint effect. In this solution, the lower limit ring 6 is first positioned to the preset position in step (3), and then the coaxial pressing mandrel pushes the radial constraint ring sleeve 4 axially to contact the lower limit ring 6. This operation ensures that the installation reference of the ring sleeve is strictly perpendicular to the axis of the needle tube 2, avoiding the ring sleeve from tilting during the pressing process. The subsequent installation of the upper limit ring 5 locks the position of the ring sleeve from the other side, making it completely fixed in the axial direction and preventing any movement.

[0015] In this embodiment, the needle tube 2 includes an upper tube 7, a lower tube 8, and a sleeve 9. The upper tube 7 is coaxially mounted on the upper side of the lower tube 8, and the sleeve 9 is coaxially disposed on the outside of the upper tube 7 and the lower tube 8 to connect them. By rotating the sleeve 9, the interval between the upper tube 7 and the lower tube 8 can be changed. With this invention employing a split structure of the upper tube 7, lower tube 8, and sleeve 9, the axial interval between the upper tube 7 and the lower tube 8 can be continuously adjusted simply by rotating the sleeve 9, thereby changing the effective length of the entire needle tube 2 to meet practical needs.

[0016] In this embodiment, the upper limit ring 5 and the lower limit ring 6 are threaded to the inner sides of the upper tube 7 and the lower tube 8, respectively. Before installing the radial constraint ring sleeve 4, after determining the length of the needle tube 2, the lower limit ring 6 inside the lower tube 8 is first rotated to axially displace it to a preset position. Then, the radial constraint ring sleeve 4 is installed, followed by the upper limit ring 5. The upper limit ring 5 is rotated to axially displace it to a preset position, thus limiting the radial constraint ring sleeve 4. In actual production, the stiffness of the helical spring 3 varies to some extent from batch to batch. Even springs with the same nominal parameters may have fluctuations of a few percent in their free length and elastic coefficient. If the position of the limit ring remains fixed, such slight differences in the spring may cause the compression force of some ejector pins to exceed the allowable range after assembly, or the preload of the radial constraint ring sleeve 4 to be inappropriate. In this invention, the operator can first measure the free length and stiffness of the helical spring 3 before assembly, and then calculate the optimal installation position of the lower limit ring 6 based on these measured values. The lower limit ring 6 inside the lower tube 8 is then rotated to precisely move it to the preset position.

[0017] In this embodiment, the spring ejector pin also includes a top limiting ring 10. The inner diameter of the top limiting ring 10 is smaller than the inner diameter of the boss of the needle shaft 1. After the entire assembly is installed into the needle tube 2, the top limiting ring 10 can be detachably connected to the opening of the needle tube 2, thereby limiting the needle shaft 1 and facilitating the smooth installation of the overall structure.

[0018] In this embodiment, in step (2), the specific way to fix one end of the helical spring 3 to the tail of the needle shaft 1 is as follows: a cross-shaped or star-shaped radial groove is pre-processed at the tail of the needle shaft 1, and a blind hole is opened in the center of the groove; after the end of the helical spring 3 is softened by high temperature tempering, a pulse current is passed through it, so that the inner wall of the blind hole and the helical spring 3 are partially melted and bonded. During the melting process of the pulse current, the groove provides additional flow and filling space for the molten metal, which avoids the molten material being squeezed out of the blind hole, and the connection is more secure.

Claims

1. A manufacturing process for a spring-loaded ejector pin, characterized in that: The spring-loaded ejector pin includes a needle shaft, a needle tube, a helical spring, and a radial constraint ring. The needle tube is a cylindrical shell open at one end and closed at the other. The needle shaft is slidably mounted on the open end of the needle tube. The helical spring is placed inside the needle tube, with its two ends connected to the bottom of the needle tube and the needle shaft, respectively. The radial constraint ring is positioned within the radially spaced gap between the helical spring and the needle tube. The manufacturing process includes the following steps: Step (1), needle installation: Provide a cylindrical needle tube with one end open and the other end closed. First, clean and degrease the inner wall of the needle tube, and then sandblast the inner wall. The area after sandblasting is used for subsequent installation of radial constraint ring sleeve. Step (2): Pre-connect the helical spring to the needle shaft. Select a helical spring with an outer diameter smaller than the inner diameter of the radial constraint ring. Fix one end of the helical spring to the tail of the needle shaft and confirm that the spring axis coincides with the needle shaft axis. Step (3), Radial constraint ring positioning and fixing: Use a coaxial press-fit mandrel to push the radial constraint ring inward from the needle tube opening end, and push it axially to the preset position on the inner wall of the needle tube; Step (4): The entire assembly is installed into the needle tube. The needle shaft and the helical spring are installed with the tail end of the needle shaft facing down. The needle shaft is vertically inserted into the needle tube from the open end. The helical spring is inserted from the center of the radial constraint ring. During the insertion process, the outer wall of the radial constraint ring contacts the sandblasted rough area of ​​the inner wall of the needle tube. A certain radial gap is maintained between the inner side of the radial constraint ring and the spring, allowing the spring to extend and retract freely but preventing it from bending radially. Step (5): The spring is connected to the bottom of the needle tube. Conductive adhesive is injected into the bottom of the needle tube through the reserved small hole on the outside of the closed end of the needle tube. The adhesive contacts the other end of the spiral spring. After the conductive adhesive cures, the spring is fixedly connected to the bottom of the needle tube.

2. The manufacturing process of a spring ejector pin according to claim 1, characterized in that: The spring ejector pin also includes an upper limit ring and a lower limit ring. The upper limit ring and the lower limit ring are coaxially fixed inside the needle tube. The upper limit ring and the lower limit ring are used to limit the two ends of the radial constraint ring sleeve respectively. In step (3), after the radial constraint ring sleeve is pushed inward from the opening end of the needle tube using a coaxial pressing mandrel, the radial constraint ring sleeve is axially pushed to contact the lower limit ring before the upper limit ring is installed.

3. The manufacturing process of a spring ejector pin according to claim 2, characterized in that: The syringe consists of an upper tube, a lower tube, and a sleeve. The upper tube is coaxially mounted on the upper side of the lower tube, and the sleeve is coaxially positioned on the outside of the upper and lower tubes to connect them. By rotating the sleeve, the gap between the upper and lower tubes can be changed.

4. The manufacturing process of a spring ejector pin according to claim 3, characterized in that: The upper limit ring and the lower limit ring are threaded to the inner sides of the upper tube and the lower tube, respectively. Before installing the radial constraint ring sleeve, after determining the length of the needle tube, first rotate the lower limit ring inside the lower tube to make it axially displace to the preset position, then install the radial constraint ring sleeve, and then install the upper limit ring. Rotate the upper limit ring to make it axially displace to the preset position to limit the radial constraint ring sleeve.

5. The manufacturing process of a spring ejector pin according to claim 4, characterized in that: The spring ejector pin also includes a top limiting ring. The inner diameter of the top limiting ring is smaller than the inner diameter of the needle shaft boss. After the entire assembly is installed into the needle tube, the top limiting ring can be detachably connected to the opening of the needle tube to limit the needle shaft.

6. The manufacturing process of a spring ejector pin according to claim 1, characterized in that: In step (2), the specific method for fixing one end of the helical spring to the tail of the needle shaft is as follows: a cross-shaped or star-shaped radial groove is pre-machined at the tail of the needle shaft, and a blind hole is opened in the center of the groove; after the end of the helical spring is softened by high temperature tempering, a pulse current is passed through it, so that the inner wall of the blind hole and the helical spring are partially melted and bonded.

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