Injection molding processing technology for electromagnetic coil assembly of magneto-rheological shock absorber

Abstract

The electromagnetic coil assembly injection molding process comprises an electromagnetic coil assembly and injection molding process steps, the electromagnetic coil assembly comprises a magnetic core, a coil, a terminal and an electric wire, a coil groove is formed in the peripheral wall of the magnetic core, and the coil is wound in the coil groove; a mounting hole is formed in the axis of the magnetic core, the terminal is mounted in the mounting hole, and the two ends of the terminal are electrically connected with the coil and the electric wire respectively; and the mounting hole is communicated with the coil groove through the through groove. The situation that magnetorheological fluid permeates into the piston and permeates outwards through an electric wire can be prevented.

Description

Technical Field

[0001] The invention relates to the technical field of shock absorbers, and in particular to an injection molding process for an electromagnetic coil assembly of a magnetorheological shock absorber. Background Art

[0002] The magnetorheological shock absorber is a new type of actuator with adjustable damping force. Its working fluid is magnetorheological fluid. When the piston and the cylinder body move relative to each other, the magnetorheological fluid will be squeezed and passed through the damping channel on the piston, so that the magnetorheological fluid will generate shear force. At the same time, the rheological properties of the magnetorheological fluid can be changed under the action of the magnetic field. Under the action of the external magnetic field, the reversible transformation between Newtonian fluid and Bingham fluid can be achieved within milliseconds. Therefore, the magnetorheological shock absorber has the characteristics of fast response speed and large damping force adjustment range. The electromagnetic coil assembly in the existing magnetorheological shock absorber includes a magnetic core and a terminal. A coil is arranged on the magnetic core. The coil is connected to one end of the terminal, and the other end of the terminal is connected to an electric wire. The electric wire is led out from the hollow piston rod, and then the coil and the terminal are injection-molded and sealed to prevent the magnetorheological fluid from contacting the coil, the terminal, and the electric wire. However, during injection molding production, since the materials of the terminals, the magnetic core and the thermoplastic are all different, the magnetorheological fluid will penetrate through the gap between the thermoplastic and the magnetic core, and then penetrate outward along the terminals through the wires, causing leakage. Summary of the invention

[0003] The purpose of the present invention is to provide an injection molding process for an electromagnetic coil assembly of a magnetorheological damper, aiming to solve the problem that the magnetorheological fluid in the existing magnetorheological damper piston will penetrate into the interior of the piston and penetrate outward through the wires.

[0004] In order to achieve the above-mentioned object, the present invention discloses an injection molding process for an electromagnetic coil assembly of a magnetorheological damper, comprising an electromagnetic coil assembly and an injection molding process step.

[0005] The electromagnetic coil assembly includes a magnetic core, a coil, a terminal, and an electric wire. A coil groove is provided on the outer peripheral wall of the magnetic core, and the coil is arranged in the coil groove; a mounting hole is provided at the axis of the magnetic core, and the terminal is installed in the mounting hole, and the two ends of the terminal are electrically connected to the coil and the electric wire respectively; the mounting hole and the coil groove are connected by a through groove.

[0006] The injection molding process includes the following steps:

[0007] Step S110: performing a first injection molding on the coil slot in the magnetic core to form an insulating layer;

[0008] Step S120: Winding the coil in the coil slot;

[0009] Step S130: welding one end of the terminal to the wire to form a first welding point;

[0010] Step S140: performing a second injection molding on the first welding position to form a terminal injection molding body, wherein a sealing ring groove is provided on the peripheral wall of the terminal injection molding body, and a sealing ring is installed in the sealing ring groove; a plurality of protrusions are provided on the lower end surface of the terminal injection molding body, and all the protrusions are connected end to end;

[0011] Step S150: Install the terminal injection molding into the mounting hole inside the magnetic core, and weld the coil to the other end of the terminal;

[0012] Step S160: performing a third injection molding process on the coil in the coil slot and the terminal injection molding body in the magnetic core to form a thermoplastic plastic layer.

[0013] Preferably, before step S110: performing a first injection molding on the coil slots in the magnetic core to form an insulating layer, the following steps are also included:

[0014] Step S100: cleaning, drying and baking the magnetic core.

[0015] Preferably, in step S130: welding one end of the terminal to the wire to form a first welding point; and step S140: performing a second injection molding on the first welding point to form a terminal injection molding body, a sealing ring groove is provided on the peripheral wall of the terminal injection molding body, and a sealing ring is installed in the sealing ring groove; a plurality of protrusions are provided on the lower end surface of the terminal injection molding body, and all the protrusions are connected end to end, and the following steps are also included between the two steps:

[0016] Step S131: dripping glue on the terminal and the first welding point.

[0017] Preferably, the coil is provided with two lead wires, the terminals and the wires are respectively in two numbers, the two lead wires are respectively electrically connected to one end of the two terminals, and the two wires are respectively electrically connected to the other end of the two terminals; the electromagnetic coil assembly also includes a wire harness wrap, which is used to wrap the two wires.

[0018] Preferably, there are two coil grooves, which are arranged on the outer peripheral wall of the magnetic core from top to bottom; a connecting groove is provided between the two coil grooves, which is arranged on the outer peripheral wall of the magnetic core; the connecting groove is arranged vertically; the through groove is arranged on the end face of the magnetic core, and the through groove and the connecting groove are arranged in the same plane.

[0019] Preferably, the protrusion is arranged in a ring shape, and the protrusion surrounds the outer side of the terminal.

[0020] Preferably, the protrusions have multiple circles, and all the protrusions are coaxially arranged with the terminal injection molding body.

[0021] Preferably, the protrusion has three circles.

[0022] The beneficial effects of the present invention are as follows: the above technical solution provides an injection molding process for the electromagnetic coil assembly of a magnetorheological shock absorber, in which the outside of the coil is injection molded to prevent the coil from contacting the magnetorheological fluid; the lower part of the terminal injection molding body is injection molded, and a sealing ring is provided on the outer wall of the terminal injection molding body to prevent the magnetorheological fluid from penetrating into the mounting hole from the gap between the mounting hole and the terminal injection molding body, thereby flowing from the hollow inner hole of the piston rod to the outside of the shock absorber; a plurality of protrusions are provided on the lower end surface of the terminal injection molding body, and all the protrusions are connected end to end, and the protrusions can play a partitioning role, which can prevent the magnetorheological fluid from penetrating into the terminal injection molding body along the terminal, and then penetrating outward through the wire.

[0023] The present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, which are used to illustrate embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Shown is a cross-sectional view of the electromagnetic coil assembly of a magnetorheological damper.

[0025] Figure 2 The figure shows the structural separation diagram of the magnetic core and the terminal injection molding in the electromagnetic coil assembly of the magnetorheological damper.

[0026] Figure 3 The figure shows the overall structure of the terminal injection molding body.

[0027] Figure 4 Shown is a cross-sectional view of the terminal molding.

[0028] Figure 5 Shown is a flow chart of the injection molding process steps for the electromagnetic coil assembly of a magnetorheological damper.

[0029] Figure 6 Another flow chart of the process steps for the injection molding of the electromagnetic coil assembly of a magnetorheological damper is shown.

[0030] Figure 7 Shown is another flow chart of the injection molding process steps of the electromagnetic coil assembly of the magnetorheological damper. DETAILED DESCRIPTION

[0031] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0032] In the description of the present invention, it should be understood that the descriptions involving orientations, such as up, down, front, back, left, right, etc., and the orientations or positional relationships indicated are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore, should not be understood as a limitation on the present invention.

[0033] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0034] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0035] refer to Figures 1 to 7 , an injection molding process for an electromagnetic coil assembly of a magnetorheological damper, comprising an electromagnetic coil assembly and an injection molding process step,

[0036] The electromagnetic coil assembly includes a magnetic core 200, a coil 221, a terminal 232, and an electric wire 231. A coil groove 220 is provided on the outer peripheral wall of the magnetic core 110, and the coil 221 is arranged in the coil groove 220; a mounting hole 210 is provided at the axis of the magnetic core 110, and the terminal 232 is installed in the mounting hole 210, and the two ends of the terminal 232 are electrically connected to the coil 221 and the electric wire 231 respectively; the mounting hole 210 and the coil groove 220 are connected through a through groove 224.

[0037] The injection molding process includes the following steps:

[0038] Step S110: performing a first injection molding process on the coil slot 220 in the magnetic core 200 to form an insulating layer;

[0039] Step S120: Winding the coil 221 in the coil slot 220;

[0040] Step S130: welding one end of the terminal 232 to the wire 231 to form a first welding point;

[0041] Step S140: performing a second injection molding process on the first welding position to form a terminal injection molding body 230, wherein a sealing ring groove 233 is provided on the peripheral wall of the terminal injection molding body 230, and a sealing ring 2331 is installed in the sealing ring groove 233; a plurality of protrusions 234 are provided on the lower end surface of the terminal injection molding body 230, and all the protrusions 234 are connected end to end;

[0042] Step S150: Install the terminal injection molding 230 into the mounting hole 210 inside the magnetic core 110, and weld the coil 221 to the other end of the terminal 232;

[0043] Step S160 : performing a third injection molding process on the coil 221 in the coil slot 220 and the terminal injection molding body 230 in the magnetic core 110 to form a thermoplastic plastic layer 240 .

[0044] The coil slot 220 in the magnetic core 200 is subjected to the first injection molding to form an insulating layer, and then the coil 221 is wound in the coil slot 220. The magnetic core 200 is made of metal material, which can prevent the coil 221 from directly contacting the magnetic core 200 to achieve an insulating effect. The two ends of the terminal 232 are electrically connected to the coil 221 and the wire 231 respectively, and an external power source can be connected through the wire 231. The wire 231 conducts electricity to the coil 221 through the terminal 232. The first welding part is subjected to the second injection molding to form a terminal injection molding body 230. The terminal injection molding body 230 wraps a part of the terminal 232 and a part of the wire 231, which can play a role in fixing and protecting the first welding part.

[0045] The outer part of the coil 221 is injection molded with a thermoplastic plastic layer 240, which can prevent the coil 221 from contacting with the magnetorheological fluid, and the thermoplastic plastic layer 240 wrapped around the outer part of the coil 221 is flush with the outer circumference of the magnetic core 200. The lower part of the terminal injection molding body 230 is injection molded with a thermoplastic plastic layer 240, which can wrap the terminal injection molding body 240 in the lower part of the mounting hole 210. However, due to the different materials of the thermoplastic plastic layer 240 and the magnetic core 200, after injection molding, there will be a certain external gap at the connection between the thermoplastic plastic layer 240 and the magnetic core 200, and the magnetorheological fluid may still penetrate into the terminal injection molding body 230 through the external gap. The hollow piston rod is installed at the upper part of the mounting hole 210, and a sealing ring 2331 is provided between the outer peripheral wall of the terminal injection molding body 230 and the mounting hole 210, which can prevent the magnetorheological fluid from penetrating into the mounting hole 210 of the magnetic core 200, thereby flowing from the inner hole of the hollow piston rod to the outside of the shock absorber. Because the terminal injection molding body 230 is first injection molded, after the terminal injection molding body 230 is inserted into the lower part of the mounting hole 210 from bottom to top, the thermoplastic plastic layer 240 is then injection molded into the lower part of the terminal injection molding body 230. There may also be a layer gap between the lower end surface of the terminal injection molding body 230 and the thermoplastic plastic layer 240. The terminal 232 can be made of copper material, and the terminal injection molding body 230 and the terminal 232 are made of different materials. There may also be a certain internal gap between the terminal injection molding body 230 and the terminal 232. The magnetorheological fluid may enter through the external gap, and then penetrate along the layer gap and the internal gap, and then penetrate to the outside along the terminal 230 and the wire 231. The route of magnetorheological fluid penetration can be as follows: Figure 1 Figure 3 , Figure 4 As shown by the arrow in , a plurality of protrusions 234 are provided on the lower end surface of the terminal injection molding body 230, and all the protrusions 234 are connected end to end. When the terminal injection molding body 230 is formed, the protrusions 234 are also formed together, and the terminal injection molding body 230 and the protrusions 234 are made of the same material. After the terminal injection molding body 230 is inserted into the lower part of the mounting hole 210 from bottom to top, the thermoplastic plastic layer 240 is injected into the lower part of the terminal injection molding body 230. The injection material of the terminal injection molding body 230 and the injection material of the thermoplastic plastic layer 240 can be the same injection material. At this time, the injected thermoplastic plastic layer 240 can partially melt the protrusions 234, so that the thermoplastic plastic layer 240 and the lower end surface of the terminal injection molding body 230 are more closely combined, and the protrusions 234 block the interlayer gap to prevent the magnetorheological fluid from passing through the interlayer gap into the inner gap, and then penetrating along the terminal 232 to the wire 231. The thermoplastic plastic layer 240 can be injection molded by an injection molding machine, and the material can be nylon.

[0046] In one embodiment, before step S110: performing a first injection molding on the coil slot 220 in the magnetic core 200 to form an insulating layer, the following steps are also included:

[0047] Step S100: cleaning, drying and baking the magnetic core 200.

[0048] In order to remove dirt such as oil and grease on the magnetic core 200, the magnetic core 200 may be cleaned before the injection molding process. Alcohol may be used for cleaning. After cleaning, an air gun may be used to blow dry the magnetic core 200, and then the magnetic core 200 may be baked.

[0049] In one embodiment, in step S130: one end of the terminal 232 is welded to the wire 231 to form a first welding point; and step S140: a second injection molding is performed on the first welding point to form a terminal injection molding body 230, a sealing ring groove 233 is provided on the peripheral wall of the terminal injection molding body 230, and a sealing ring 2331 is installed in the sealing ring groove 233; a plurality of protrusions 234 are provided on the lower end surface of the terminal injection molding body 230, and all the protrusions 234 are connected end to end. The following steps are also included between the two steps: step S131: glue is dripped on the terminal 232 and the first welding point. One end of the terminal 232 is welded to the wire 231 to form a first welding point, and glue is dripped on the first welding point to wrap the entire terminal 232 and the first welding point. A thermoplastic plastic layer 240 is injected into the lower part of the terminal injection molding body 230. The thermoplastic plastic layer 240 and the dripping glue can fit more closely, further preventing the magnetorheological fluid from entering the inner gap and then penetrating onto the wire 131 along the terminal 152. One end of the terminal 232 is welded to the wire 231, and spot welding can be used for welding. The coil 221 is welded to the other end of the terminal 232 by laser welding. Compared with the traditional tin dipping solution, the temperature of the tin pool is relatively high. When dipping in tin, the terminal 232 wrapped in the glue and the first welding point will be damaged. This solution adopts laser welding for welding. Its welding temperature is lower than the tin dipping temperature, and the laser welding area is smaller. Tin dipping will damage the terminal 232 and the first welding point wrapped in the glue to a large extent. By using laser welding, the part of the terminal 232 and the first welding point wrapped in the glue can be minimized.

[0050] In one embodiment, the coil 221 is provided with two lead wires 222, and the terminals 232 and the wires 231 are each provided with two, and the two lead wires 221 are respectively electrically connected to one end of the two terminals 232, and the two wires 231 are respectively electrically connected to the other end of the two terminals 232; the electromagnetic coil assembly also includes a wire harness wrap 2311, and the wire harness wrap 2311 is used to wrap the two wires 231. The wire 231 inputs current, which is transmitted to the lead wire 222 through the terminal 232, and the lead wire 222 is then transmitted to the coil 221, and a loop needs to be formed, so the number of wires 231, the terminal 232, and the lead wire 222 is two. The outside of the coil 221, the outside of the lead wire 222, and the lower part of the terminal injection molding body 230 are all wrapped and sealed by the thermoplastic plastic layer 240. The two wires 231 are wrapped with the wire harness wrap 2311 to further protect the two wires 231.

[0051] In one embodiment, there are two coil slots 220, and the two coil slots 220 are arranged on the outer peripheral wall of the magnetic core 110 from top to bottom; a connecting slot 223 is arranged between the two coil slots 220, and the connecting slot 223 is arranged on the outer peripheral wall of the magnetic core 110; the connecting slot 223 is arranged vertically; the through slot 224 is arranged on the end surface of the magnetic core 200, and the through slot 224 and the connecting slot 223 are arranged in the same plane. There are two coil slots 220, and the coil 221 is reversely wound in the two coil slots 220. Compared with the single coil structure, the magnetic induction intensity of the double coil structure is more uniform, and the self-inductance effect of the single coil is eliminated. The connecting slot 223 is arranged on the outer peripheral wall of the magnetic core 110, which can facilitate the coil 221 to enter the other coil slot 220 from one coil slot 220, and can also facilitate the processing of the connecting slot 223 on the magnetic core 200. The through groove 224 is arranged on the end surface of the magnetic core 200, so that the through groove 224 can be conveniently processed on the magnetic core 200. The through groove 224 and the connecting groove 223 are arranged in the same plane, so that the through groove 224 and the connecting groove 223 can be conveniently processed on the magnetic core 200. During the injection molding, the injection molding machine first covers the lower part of the terminal injection molding body 230 with the thermoplastic plastic layer 240, then enters the first coil groove 220 along the through groove 224, and then enters the other coil groove 220 along the connecting groove 223.

[0052] In one embodiment, the protrusion 234 is arranged in a ring shape, and the protrusion 234 is arranged around the outside of the terminal 232. The protrusion 234 is arranged in a ring shape, and can separate the layer gap from a 360° circumference. Of course, in addition to the ring shape, other shapes can be used, as long as the protrusion 234 is arranged end to end.

[0053] In one embodiment, the protrusion 234 has multiple circles, and all the protrusions 234 are coaxially arranged with the injection molding body of the terminal 232. The multiple circles of protrusions 234 are arranged, and the thermoplastic plastic layer 240 is injection-molded to the lower part of the terminal injection molding body 230. The injection molding material of the terminal injection molding body 230 is the same as the injection molding material of the thermoplastic plastic layer 240. At this time, the injected thermoplastic plastic layer 240 can partially melt the protrusions 234, so that the thermoplastic plastic layer 240 is more tightly combined with the lower end surface of the terminal injection molding body 230, and the layer gap can be more effectively isolated.

[0054] In one embodiment, the protrusion 234 has three circles. Providing three circles of protrusions 234 can more effectively isolate the layer gap.

[0055] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. An injection molding process for an electromagnetic coil assembly of a magnetorheological damper, comprising an electromagnetic coil assembly and an injection molding process step, Features: The electromagnetic coil assembly includes a magnetic core, a coil, a terminal, and an electric wire. A coil groove is provided on the outer peripheral wall of the magnetic core, and the coil is arranged in the coil groove; a mounting hole is provided at the axis of the magnetic core, and the terminal is installed in the mounting hole, and the two ends of the terminal are electrically connected to the coil and the electric wire respectively; the mounting hole and the coil groove are connected by a through groove. The injection molding process includes the following steps: Step S110: performing a first injection molding on the coil slot in the magnetic core to form an insulating layer; Step S120: Winding the coil in the coil slot; Step S130: welding one end of the terminal to the wire to form a first welding point; Step S140: performing a second injection molding on the first welding position to form a terminal injection molding body, wherein a sealing ring groove is provided on the peripheral wall of the terminal injection molding body, and a sealing ring is installed in the sealing ring groove; a plurality of protrusions are provided on the lower end surface of the terminal injection molding body, and all the protrusions are connected end to end; Step S150: Install the terminal injection molding into the mounting hole inside the magnetic core, and weld the coil to the other end of the terminal; Step S160: performing a third injection molding process on the coil in the coil slot and the terminal injection molding body in the magnetic core to form a thermoplastic plastic layer.

2. The injection molding process of the electromagnetic coil assembly of a magnetorheological damper according to claim 1, It is characterized in that Before step S110: performing a first injection molding on the coil slots in the magnetic core to form an insulating layer, the following steps are also included: Step S100: cleaning, drying and baking the magnetic core.

3. The injection molding process of the electromagnetic coil assembly of a magnetorheological damper according to claim 1, It is characterized in that In step S130: welding one end of the terminal to the wire to form a first welding point; and in step S140: performing a second injection molding on the first welding point to form a terminal injection molding body, a sealing ring groove is provided on the peripheral wall of the terminal injection molding body, and a sealing ring is installed in the sealing ring groove; a plurality of protrusions are provided on the lower end surface of the terminal injection molding body, and all the protrusions are connected end to end, and the following steps are also included between the two steps: Step S131: dripping glue on the terminal and the first welding point.

4. The injection molding process of the electromagnetic coil assembly of a magnetorheological damper according to claim 1, It is characterized in that The coil is provided with two lead wires, and there are two terminals and two wires respectively. The two lead wires are electrically connected to one end of the two terminals respectively, and the two wires are electrically connected to the other end of the two terminals respectively; the electromagnetic coil assembly also includes a wire harness wrap, which is used to wrap the two wires.

5. The injection molding process of the electromagnetic coil assembly of a magnetorheological damper according to claim 1, It is characterized in that There are two coil grooves, which are arranged on the outer peripheral wall of the magnetic core from top to bottom; a connecting groove is arranged between the two coil grooves, which is arranged on the outer peripheral wall of the magnetic core; the connecting groove is arranged vertically; the through groove is arranged on the end face of the magnetic core, and the through groove and the connecting groove are arranged in the same plane.

6. The injection molding process of the electromagnetic coil assembly of a magnetorheological damper according to claim 1, It is characterized in that The protrusion is arranged in a ring shape and surrounds the outer side of the terminal.

7. The injection molding process of the electromagnetic coil assembly of a magnetorheological damper according to claim 6, It is characterized in that The protrusions have multiple circles, and all the protrusions are coaxially arranged with the terminal injection molding body.

8. The injection molding process of the electromagnetic coil assembly of a magnetorheological damper according to claim 7, It is characterized in that The protrusion has three circles.

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