Process for manufacturing a spring-coated wire

Abstract

This invention discloses a manufacturing process for a coated spring. The process steps are as follows: S01: Wind a straight tube around an iron rod according to the spring design requirements and fix both ends of the straight tube; S02: Place the iron rod and the straight tube wound on the iron rod into an oven for heating to form a coated tube; S03: Cut off the two ends of the coated tube used for fixing and insert the spring into the shaped coated tube; S04: Heat both ends of the coated tube, and place the heated coated tube into an extrusion mold for extrusion molding to complete the sealing of both ends of the coated tube; The coated spring manufactured by this process can select an appropriate thickness according to requirements, has better toughness after baking, and the good integrity of the straight tube brings better resistance to media penetration. Moreover, the surface is smooth and the sealed ends will not crack.

Description

Technical Field

[0001] This invention relates to the field of spring coating technology, specifically to a manufacturing process for coated springs. Background Technology

[0002] Coated springs are widely used in industries such as electrical, automotive, and chemical manufacturing. This involves covering the spring with a layer of plastic, selecting plastics with properties such as flame retardancy, waterproofing, heat insulation, anti-slip properties, electrical insulation, and corrosion resistance as needed. Because of the outer plastic layer, the spring also possesses these properties. Currently, the manufacturing method for coated springs is relatively simple. Typically, heat-shrink tubing is inserted into the spring, and it is sintered in a furnace. Coated springs produced using this method are too thin, easily breakable, have poor resistance to media penetration, and are prone to surface wrinkling and cracking at the sealing points. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a manufacturing process for a coated spring, which solves the problems of existing coated springs being too thin, prone to breakage, having poor resistance to medium penetration, and having a surface that is prone to wrinkling and port seals that are prone to cracking.

[0004] The present invention is achieved through the following technical solution.

[0005] The present invention discloses a manufacturing process for a coated spring, comprising the following steps:

[0006] S01: Wrap the straight tube around the iron rod according to the spring design requirements, and fix both ends of the straight tube;

[0007] S02: Place the iron rod and the straight tube wound around the iron rod into an oven and heat them to form a coated tube;

[0008] S03: Cut off the two ends of the covered tube used for fixing, and insert the spring into the shaped covered tube;

[0009] S04: Heat both ends of the coated tube, and then place the heated coated tube into the extrusion mold to extrude and shape it, thus completing the sealing of both ends of the coated tube.

[0010] Furthermore, the inner diameter of the straight tube is larger than the diameter of the spring wire.

[0011] Furthermore, the outer diameter of the iron rod is smaller than the inner diameter of the spring minus the thickness of two straight tube walls, and the length of the iron rod is greater than the total length of the spring.

[0012] Furthermore, the heating temperature and time inside the oven are adjusted according to the material of the plastic, with the heating temperature being lower than the melting temperature.

[0013] Furthermore, the extrusion die is a conical die with a taper of no more than 45°.

[0014] Furthermore, the maximum inner diameter of the mold should be greater than the maximum outer diameter of the same type of plastic-coated pipe.

[0015] The beneficial effects of the present invention are as follows: The spring coating manufacturing process provided by the present invention is applicable to the production of spring coatings made of a variety of plastic materials. The tools and molds used are also relatively simple and inexpensive. The processing time is short, the efficiency is high, and the process is simple and easy to operate. The spring coating produced by this process can be selected with appropriate thickness according to requirements. After baking, the toughness is better, the integrity of the straight tube is good, resulting in better resistance to media penetration. Moreover, the surface is smooth and the end will not crack after sealing. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the coated tube according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the sealing process of the encapsulated tube according to an embodiment of the present invention. Detailed Implementation

[0019] The following is combined with Figure 1-2 The present invention will be described in detail below. For ease of description, the directions referred to below are defined as follows: the directions of up, down, left, right, front, and back mentioned below are the same as... Figure 1 The directions of the projection relationship are consistent in all directions: up, down, left, right, front, and back.

[0020] Combined with appendix Figure 1-2 The manufacturing process of the covered spring is as follows: S01: The straight tube is wound around the iron rod according to the design requirements of the spring, and the two ends of the straight tube are fixed.

[0021] S02: Place the iron rod and the straight tube wound around the iron rod into an oven and heat them to form a coated tube;

[0022] S03: Cut off the two ends of the covered tube used for fixing, and insert the spring into the shaped covered tube;

[0023] S04: Heat both ends of the coated tube, and then place the heated coated tube into the extrusion mold to extrude and shape it, thus completing the sealing of both ends of the coated tube.

[0024] The straight tube is wound around the iron rod according to the shape of the spring (mean diameter, pitch), and both ends are fixed to the iron rod. The whole thing is placed vertically in the oven. After heating for a period of time, it is taken out and the shaped coated tube is obtained.

[0025] The two ends of the straight tube are preferably attached and fixed to the iron rod in a vertical position parallel to the iron rod, so that the coated tube after baking and heating can be easily removed from the iron rod.

[0026] When selecting a straight tube, the inner diameter of the tube should be slightly larger than the spring wire diameter. The thickness can be selected according to the application, but it should not be too thin, otherwise it may cause dents and deformation during shaping. The inner diameter of the straight tube should be slightly larger than the spring wire diameter to facilitate the subsequent insertion of the spring into the covered tube.

[0027] When selecting an iron rod, its outer diameter should be slightly smaller than the inner diameter of the spring minus the thickness of two straight tube walls, and its length should be greater than the total length of the spring. The outer diameter of the iron rod being slightly smaller than the inner diameter of the spring minus the thickness of two straight tube walls is to ensure that the size of the covering tube corresponds to the spring size and can be well fitted. The length of the iron rod being greater than the length of the spring facilitates fixing and removal during baking.

[0028] The heating temperature and time in the oven are adjusted according to the material of the straight tube. The heating temperature should not exceed the melting temperature of the straight tube. The purpose of heating is to keep the deformation of the straight tube stable for a long time and to release the internal stress when the straight tube is wound onto the iron rod.

[0029] Remove the two ends of the tube used to fix it to the iron rod, and put the spring into the shaped tube. The two ends of the tube need to be sealed at this time to prevent the spring from slipping out of the tube during long-term use.

[0030] For the covered tubes with springs of different shapes and sizes, different extrusion molds are prepared in advance. The tube opening is heated using heating equipment. After the plastic at the end of the covered tube melts, it is extruded into the extrusion mold to form a shape, so that the end of the covered tube and the end of the spring are fixed together.

[0031] The extrusion molding die should be designed to be conical, with a taper of no more than 45°. When the tube opening is in the molten state, the tube opening can be self-sealed by extrusion in the presence of the extrusion molding die. The maximum inner diameter of the die should be greater than the maximum outer diameter of the tube of the same type of plastic so that it can be used for tubes of different specifications of the same type of plastic. Different types of plastics should use different dies.

[0032] During the heating process, it is important to note that only the port portion should be heated. If the two ends of the spring are designed to be close to the middle coil, tools should be used to separate them appropriately so that the port is in a position suitable for heating without damaging other areas of the encased tube.

[0033] During heating, the state of the port should be observed at all times. When the port becomes transparent and round, it means that it has melted to a state where it can be formed. At this time, it should be squeezed into the forming mold that is also being heated, first slowly and then quickly. That is, the port of the covering tube should be shrunken inward first and then quickly sealed. During the extrusion process, appropriate rotation can be performed to make the sealed port smoother.

[0034] Specific example 1:

[0035] Taking the standard spring of ISO / TC 227 as an example for covering:

[0036] The spring (I SO / TC 227) is a general cylindrical compression spring with a mean diameter of 50 mm, a wire diameter of 4 mm, a length of 112 mm, a pitch of 20 mm, and 6 coils.

[0037] Straight tube dimensions: thickness 0.5mm, outer diameter 6mm (inner diameter 5mm, greater than the spring's inner diameter 4mm), length 1000mm (must be greater than the spring's length 950mm).

[0038] The iron rod has the following dimensions: length 150mm (greater than the spring length 112mm), outer diameter 43mm (slightly smaller than the spring's mean diameter minus the straight tube's outer diameter).

[0039] A hot air gun can be used as the heating device (other devices with sufficient power and a heating area that is not too large can also be selected).

[0040] The extrusion die has the following dimensions: maximum inner diameter (i.e., bottom circle diameter of the conical groove) 12mm and taper 45°.

[0041] Preparation process:

[0042] As described in the manufacturing steps, the straight tube is wound around the iron rod in the shape of a spring. After the two ends are fixed, it is placed vertically in the oven for heating and shaping. After shaping, the covered tube is removed from the iron rod.

[0043] Remove the parts used for fixing at both ends of the tube, heat one of the ends, and heat the mold at the same time. When the end is about to melt, extrude it into the extrusion mold at high temperature to form the shape.

[0044] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand and implement the present invention. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A manufacturing process for a coated spring, characterized in that: S01: Wrap the straight tube around the iron rod according to the spring design requirements, and fix both ends of the straight tube; S02: Place the iron rod and the straight tube wound around the iron rod into an oven and heat them to form a coated tube; S03: Cut off the two ends of the covered tube used for fixing, and insert the spring into the shaped covered tube; S04: Heat both ends of the coated tube, put the heated coated tube into the extrusion mold to extrude and form it, and complete the sealing of both ends of the coated tube; The heating temperature and time inside the oven are adjusted according to the material of the plastic, and the heating temperature is lower than the melting temperature.

2. The process of claim 1 wherein: The inner diameter of the straight tube is larger than the diameter of the spring wire.

3. The process of claim 1 wherein: The outer diameter of the iron rod is smaller than the inner diameter of the spring minus the thickness of two straight tube walls, and the length of the iron rod is greater than the total length of the spring.

4. The process of claim 1 wherein: The extrusion die is a conical die with a taper of no more than 45°.

5. The process of claim 1 wherein: The maximum inner diameter of the mold should be greater than the maximum outer diameter of the same type of plastic-coated pipe.

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