CN220727269U - Electromagnetic coil - Google Patents

Abstract

The utility model relates to the technical field of electromagnetic valves, and discloses an electromagnetic coil. The electromagnetic coil comprises a shell, a coil assembly, a plug-in shell and two pins, wherein the shell is wrapped outside the coil assembly, and the two pins are arranged at intervals and are connected with the coil assembly; the plug-in shell is arranged on one side of the shell, a plug-in port is formed in the plug-in shell, two pins penetrate through the plug-in shell and at least partially extend into the plug-in port, a water containing groove is formed in the bottom surface of the plug-in port, and the water containing groove is respectively arranged around the two pins. When water enters along the side wall of the insertion port, the water can flow into the water containing groove. Because the water containing groove is respectively arranged around the pins, the plane between the two pins is cut off, even if a small amount of water flows through one pin, the water can flow into the water containing groove between the two pins and remain in the water containing groove, and can not flow onto the other pin again to lead to conduction between the two pins, so that the coil assembly is prevented from being shorted, and the service life of the electromagnetic valve is ensured.

Description

Electromagnetic coil

Technical Field

The utility model relates to the technical field of electromagnetic valves, in particular to an electromagnetic coil.

Background

Solenoid valves are electromagnetic control industrial equipment, are automatic basic elements used for controlling fluids, and belong to actuators for adjusting the direction, flow, speed and other parameters of a medium in an industrial control system. One core component of the electromagnetic valve is an electromagnetic coil.

As shown in fig. 1 and 2, in the prior art, the electromagnetic coil mainly includes a housing 100, a coil assembly, a plug housing 200 and two pins 300, wherein the housing 100 is wrapped outside the coil assembly, the two pins 300 are electrically connected with the coil assembly, the plug housing 200 is disposed at one side of the housing 100, a plug socket 210 is formed in the plug housing 100, and the two pins 300 at least partially extend into the plug socket 210. When in use, the plug interface 210 faces upwards, and the plug 400 can be plugged in the plug interface 210 and electrically connected with the two pins 300, so that the coil assembly is electrified to generate electromagnetic force, and then the electromagnetic valve is started.

Since the socket 210 is generally disposed upward, in order to prevent water from entering the socket 210 along the gap between the plug 400 and the socket housing 200, the head of the plug 400 is circumferentially provided with the sealing ring 500 in the prior art, and when the plug 400 is inserted into the socket 210, the sealing ring 500 is in interference fit with the sidewall of the socket 210. However, as the waterproof level requirements increase, the waterproof requirements cannot be met by only the seal ring 500, and a small amount of water inevitably enters the socket through the slit. Once water enters the socket 210, the water flows to the bottom surface 220 of the socket 210 along the side wall of the socket 210, and because the bottom surface 220 is a plane, the water flows to the two pins 300 sequentially along the plane, and because the water has conductivity, the two pins 300 form electrical conduction, thereby causing a short circuit of the coil assembly, failing to start the electromagnetic valve, and finally failing to cause the electromagnetic valve.

Accordingly, there is a need to provide an electromagnetic coil that solves the above-mentioned problems.

Disclosure of Invention

The utility model aims to provide an electromagnetic coil which can prevent water entering an inserting port from leading two pins through, avoid a coil assembly from being short-circuited and ensure the service life of an electromagnetic valve.

In order to achieve the purpose, the utility model is realized by the following technical scheme:

an electromagnetic coil, comprising:

the shell and the coil assembly are wrapped outside the coil assembly;

the two contact pins are arranged at intervals and are connected with the coil assembly;

the plug-in shell is arranged on one side of the shell, a plug-in port is formed in the plug-in shell, two pins penetrate through the plug-in shell and at least partially extend into the plug-in port, a water containing groove is formed in the bottom surface of the plug-in port, and the water containing groove is respectively arranged around the two pins.

As an alternative, the electromagnetic coil further includes a sealing member, the sealing member is embedded in the water containing groove and protrudes out of the Rong Shuicao along the axial direction of the pin, and the sealing member is used for sealing the water containing groove and blocking the two pins.

As an alternative, the water containing groove is spaced from the contact pin.

As an alternative, the water containing groove is configured into a Chinese character 'ri' shape structure and comprises an annular groove and a straight groove, wherein the annular groove is circumferentially arranged along the circumferential edge of the insertion port, and the straight groove is positioned between the two insertion pins and two ends of the straight groove are communicated with the annular groove;

the sealing element is also constructed into a ' Chinese character ' ri ' shaped structure and comprises an annular part and a blocking part, wherein the annular part is embedded in the annular groove, the blocking part is embedded in the straight groove, two ends of the blocking part are respectively connected with the annular part, and the blocking part protrudes out of the Rong Shuicao along the axial direction of the contact pin so as to separate the two contact pins.

As an alternative scheme, two water containing tanks are arranged at intervals, the two water containing tanks are respectively arranged around the corresponding pins, and the Rong Shuicao is communicated with the surfaces of the pins;

the two sealing elements are respectively embedded in the corresponding water containing grooves, and the sealing elements are sleeved outside the contact pins and in interference fit with the contact pins.

As an alternative, the sealing member is configured as a boss structure, and includes a first waterproof portion and a second waterproof portion that are coaxially disposed, the outer diameter of the first waterproof portion is larger than the outer diameter of the second waterproof portion, the first waterproof portion is embedded in the water containing groove, and the second waterproof portion protrudes from the water containing groove along the axial direction of the pin.

As an alternative, the seal is made of rubber material.

As an alternative, the sealing element is integrally formed with the plug housing.

As an alternative, the housing and the plug housing are integrally formed and manufactured by an over-molding process.

As an alternative scheme, the coil assembly comprises enameled wires and a coil framework, wherein two contact pins are arranged at intervals and are both fixed on the coil framework, and the enameled wires are wound on the coil framework, and two ends of the enameled wires are respectively connected with the corresponding contact pins.

The beneficial effects of the utility model are as follows:

according to the electromagnetic coil provided by the utility model, the water containing grooves are formed in the bottom surface of the plug-in port, and the water containing grooves are respectively arranged around the pins, so that when a small amount of water enters along the side wall of the plug-in port through the gap between the plug and the plug-in shell, the water flow path flows from the periphery to the middle, and therefore, the water also flows into the water containing grooves. Because the water containing groove is respectively arranged around the pins, the plane between the two pins is cut off, even if a small amount of water flows through one pin, the water can flow into the water containing groove between the two pins and remain in the water containing groove, and can not flow onto the other pin again to lead to conduction between the two pins, so that the coil assembly is prevented from being shorted, and the service life of the electromagnetic valve is ensured.

Drawings

For a more obvious and understandable description of embodiments of the utility model or solutions according to the prior art, reference will be made to the accompanying drawings, which are used in the description of the embodiments or the prior art and which are examples of the utility model, and from which other drawings can be obtained without inventive effort for a person skilled in the art.

FIG. 1 is an exploded view of a solenoid and plug provided in the prior art;

FIG. 2 is a schematic diagram of a prior art electromagnetic coil;

FIG. 3 is a schematic structural diagram of an electromagnetic coil according to a first embodiment of the present utility model;

FIG. 4 is an axial cross-sectional view of a solenoid coil provided in accordance with a first embodiment of the present utility model;

FIG. 5 is an exploded view of a coil assembly according to a first embodiment of the present utility model;

FIG. 6 is a schematic view of a structure of a plug housing according to a first embodiment of the present utility model;

FIG. 7 is a schematic illustration showing the mating of a plug housing and a seal according to a first embodiment of the present utility model;

FIG. 8 is a schematic view of a seal member according to a first embodiment of the present utility model;

fig. 9 is a schematic structural diagram of a plug housing according to a second embodiment of the present utility model;

FIG. 10 is a schematic diagram illustrating the mating of a plug housing and a seal according to a second embodiment of the present utility model;

fig. 11 is a schematic structural diagram of a seal member according to a second embodiment of the present utility model.

In fig. 1 and 2:

100. a housing; 200. a plug housing; 210. an interface; 220. a bottom surface; 300. a contact pin; 400. a plug; 500. a seal ring;

fig. 3 to 11:

1. a housing;

2. a coil assembly; 21. enamelled wires; 22. a coil bobbin; 221. a first stop portion; 222. a winding part; 223. a second stop portion;

3. a contact pin;

4. a plug housing; 41. an interface; 411. a bottom surface; 42. rong Shuicao; 421. an annular groove; 422. a straight groove;

5. a seal; 51. an annular portion; 52. a blocking portion; 53. a first waterproof part; 54. and a second waterproof part.

Detailed Description

The utility model is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present utility model are shown in the drawings.

In the description of the present utility model, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are orientation or positional relationships based on those shown in the drawings, merely for convenience of description and simplicity of operation, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the utility model. Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for distinguishing between them.

Example 1

The present embodiment provides a solenoid coil that can be used in a solenoid valve. As shown in fig. 3 to 6, the electromagnetic coil comprises a shell 1, a coil assembly 2, a plug-in shell 4 and two pins 3, wherein the shell 1 is wrapped outside the coil assembly 2, so that the coil assembly 2 is protected, and the service life of the electromagnetic coil is prolonged. The coil assembly 2 comprises an enameled wire 21 and a coil framework 22, the two contact pins 3 are arranged at intervals and are fixed on the coil framework 22, the enameled wire 21 is wound on the coil framework 22, and two ends (a winding starting end and a winding tail end) of the enameled wire 21 are respectively connected with the corresponding contact pins 3. The plug housing 4 is disposed at one side of the housing 1, a plug interface 41 is formed in the plug housing 4, and two pins 3 penetrate through the plug housing 4 and at least partially extend into the plug interface 41. The plug interface 41 is used for being matched with an external plug, and the plug is electrically connected with the two pins 3 after being inserted into the plug interface 41, so that the coil assembly 2 is electrified to generate electromagnetic force, and then the electromagnetic valve is started.

Specifically, as shown in fig. 5, the coil bobbin 22 includes a winding portion 222, a first stopping portion 221 and a second stopping portion 223, the winding portion 222 is in a cylindrical structure for winding the enameled wire 21, and the first stopping portion 221 and the second stopping portion 223 are respectively disposed at two ends of the winding portion 222 along an axial direction, so that the coil bobbin 22 is configured into an "i" shape structure, and the first stopping portion 221 and the second stopping portion 223 can play a stopping role on the enameled wire 21 to prevent the enameled wire 21 from falling off from two axial ends of the winding portion 222. Both the two contact pins 3 are fixed on one side of the first stop part 221, and the contact pins 3 are of an L-shaped structure, so that the actual use requirements can be met.

Preferably, as shown in fig. 3, the housing 1 and the plug housing 4 are of an integrally formed structure and are manufactured by an over-molding process. Firstly, the shell 1 and the plug housing 4 are of an integrated structure, so that the process of independently assembling the shell 1 and the plug housing 4 is omitted, and the assembling time is saved. Secondly, the shell 1 and the plug housing 4 are molded by a plastic coating process, wherein the plastic coating process is a process for manufacturing a single part from two or more different materials, specifically, when the shell 1 and the plug housing 4 are manufactured, a metal material is firstly molded into a product in one mold, then the product is used as a base material in another mold, and a layer of plastic material is further molded on the outer surface of the product, so that an integrated and dual-material product is formed, the inner layer of the product is made of the metal material, the structural strength of the whole shell is improved, the outer layer of the product is made of the plastic material, and the coil assembly 2 and the contact pin 3 can play a role in insulation protection.

In the prior art, as shown in fig. 1 and 2, a sealing ring 500 is circumferentially disposed around the head of the plug 400, and when the plug 400 is inserted into the socket 210, the sealing ring 500 is in interference fit with the sidewall of the socket 210, so as to prevent water from entering the socket 210 along the gap between the plug 400 and the socket housing 200. However, as the waterproof level requirements increase, the waterproof requirements cannot be met by only the seal ring 500, and a small amount of water inevitably enters the socket through the slit. Once water enters the socket 210, the water flows to the bottom surface 220 of the socket 210 along the side wall of the socket 210, and because the bottom surface 220 is a plane, the water flows to the two pins 300 sequentially along the plane, and because the water has conductivity, the two pins 300 form electrical conduction, thereby causing a short circuit of the coil assembly, failing to start the electromagnetic valve, and finally failing to cause the electromagnetic valve.

In order to solve the above-described problem, as shown in fig. 6, the bottom surface 411 of the socket 41 is formed with water receiving grooves 42, rong Shuicao 42 respectively provided around the two pins 3, and in this embodiment, the water receiving grooves 42 are provided at intervals from the pins 3. When a small amount of water enters along the side wall of the plug 41, the water flows along the bottom 411 of the plug 41 from the periphery to the middle, so that the water flows into the water tank 42. And because the water containing groove 42 is respectively arranged around the pins 3, the plane paths between the two pins 3 are cut off, even if a small amount of water flows through one pin 3, the water can flow to the water containing groove 42 between the two pins 3 and remain in the water containing groove 42, and can not flow to the other pin 3 again to lead to conduction between the two pins 3, thereby avoiding the occurrence of short circuit of the coil assembly 2 and ensuring the service life of the electromagnetic valve.

In order to achieve the spacing between the water receiving grooves 42 and the pins 3, alternatively, in some embodiments, the water receiving grooves 42 may be configured as two water receiving grooves 42 arranged at intervals, for example, two annular or square annular water receiving grooves 42, where the two annular water receiving grooves 42 are respectively arranged around the corresponding pins 3 and have a certain spacing from the pins 3. In other embodiments, the water receiving groove 42 may be configured as a water receiving groove 42 that is connected to each other, for example, a "ri" or "8" type water receiving groove 42, and this type of water receiving groove 42 may be divided into two annular grooves, each of which is surrounded on the periphery of the corresponding pin 3 and has a certain interval from the pin 3.

Specifically, as shown in fig. 6, in the present embodiment, the water containing groove 42 is constructed in a "sun" shape structure including an annular groove 421 and a straight groove 422, the annular groove 421 being provided circumferentially along the circumferential edge of the plug-in port 41, the straight groove 422 being located between the two pins 3 and communicating with the annular groove 421 at both ends thereof. By adopting such an arrangement, the entire water containing groove 42 can be divided into two annular grooves, each of which is provided around the periphery of the corresponding pin 3 with a certain interval from the pin 3. When a small amount of water enters along the side wall of the plug 41, the water flows into the annular groove 421. The bottom surface 411 of the socket 41 is completely blocked by the straight slot 422, that is, the plane path between the two pins 3 is blocked, even if a small amount of water flows through one pin 3 or flows onto the two pins 3 from the periphery of the bottom surface 411, the water finally flows into the straight slot 422 through the corresponding pin 3, and does not flow onto the other pin 3 to cause conduction between the two pins 3, thereby avoiding short circuit of the coil assembly 2 and ensuring the service life of the electromagnetic valve.

As shown in fig. 7, in some embodiments, the electromagnetic coil further includes a sealing member 5, where the sealing member 5 is embedded in the water containing groove 42 and protrudes from the water containing groove 42 along the axial direction of the pins 3, and the sealing member 5 is used to seal the water containing groove 42 and isolate the two pins 3. Specifically, in combination with fig. 6 and 8, the seal member 5 is also configured in a "sun" shape structure including an annular portion 51 and a blocking portion 52, the annular portion 51 is embedded in the annular groove 421, the blocking portion 52 is embedded in the straight groove 422 and both ends thereof are respectively connected to the annular portion 51, the blocking portion 52 is disposed protruding from the water receiving groove 42 in the axial direction of the pins 3, that is, the blocking portion 52 is disposed higher than the bottom surface 411 of the plug port 41 to block the two pins 3. The sealing member 5 performs a sealing function on the water containing tank 42 through interference fit with the water containing tank 42, so that most water is blocked outside the sealing member 5, and water is prevented from being fully accumulated in the water containing tank 42. Even if a small amount of water enters the water receiving tank 42, it flows along the path of the water receiving tank 42 and remains in the water receiving tank 42, and does not directly flow onto the pin 3. The water blocked outside the sealing member 5 will have a portion flowing onto the bottom surface 411 of the plug interface 41, and since the blocking portion 52 is higher than the bottom surface 411 of the plug interface 41, the blocking portion 52 can form a blocking effect between the two pins 3, so as to prevent the water flowing onto one pin 3 and then onto the other pin 3, thereby causing conduction between the two pins 3. The height of the annular portion 51 may be flush with the height of the blocking portion 52 or with the bottom 411 of the plug connector 41.

Preferably, the sealing member 5 is made of rubber material, and the sealing member 5 made of rubber material can ensure good sealing effect and has better high temperature resistance, low temperature resistance and insulating property.

Preferably, the seal 5 is integrally formed with the plug housing 4. Specifically, the sealing element 5 can be injection molded firstly, then the sealing element 5 is put into a mold for manufacturing the plug housing 4, and the plug housing 4 is injection molded, so that the sealing element 5 is integrally molded on the plug housing 4, the process of independently assembling the sealing element 5 and the plug housing 4 is omitted, and the assembly time is saved. In other embodiments, the sealing member 5 and the plug housing 4 may be formed separately, and then the sealing member 5 is embedded into the water receiving groove 42 of the plug housing 4 by a tool, so that the sealing member 5 and the plug housing 4 are fixed together by interference fit.

Example two

The electromagnetic coil provided in this embodiment is basically the same as that provided in the first embodiment, and the same is not described here, except that the shapes of the water containing groove 42 and the sealing member 5 are different.

Specifically, as shown in fig. 9 and 10, in the present embodiment, two water receiving tanks 42 are provided, the two water receiving tanks 42 are provided at intervals, the water receiving tanks 42 are circular, the two water receiving tanks 42 are provided around the corresponding pins 3, respectively, and the water receiving tanks 42 are communicated with the surfaces of the pins 3. When a small amount of water enters along the side wall of the plug-in port 41, the water flows into the water containing groove 42 along the bottom surface 411 of the plug-in port 41 and stays in the water containing groove 42, so that the two pins 3 are prevented from being conducted due to the fact that water flows onto one pin 3 and then flows onto the other pin 3, short circuit of the coil assembly 2 is avoided, and the service life of the electromagnetic valve is guaranteed.

On the basis, in some embodiments, sealing elements 5 are further arranged in the water containing groove 42, two sealing elements 5 are also arranged, two sealing elements 5 are respectively embedded in the corresponding water containing groove 42, the sealing elements 5 are sleeved outside the contact pin 3 and are in interference fit with the contact pin 3, and the sealing elements 5 are arranged in a manner that the sealing elements 5 protrude out of Rong Shuicao 42 along the circumferential direction of the contact pin 3, namely, the sealing elements 5 are higher than the bottom surface 411 of the plug interface 41. The sealing member 5 plays a role in sealing the water containing groove 42 through interference fit with the water containing groove 42, so that most water is blocked outside the sealing member 5, and the water is prevented from being accumulated in the water containing groove 42 to corrode the contact pin 3. Even a small amount of water enters the water receiving tank 42, it remains in the water receiving tank 42 and does not flow onto both pins 3 at the same time. Water blocked outside the sealing member 5 remains on the bottom surface 411 of the socket 41, and since the sealing member 5 is higher than the bottom surface 411 of the socket 41, the sealing member 5 can form a blocking effect between the two pins 3, preventing water from flowing through the two pins 3 at the same time to cause conduction between the two pins 3.

Preferably, as shown in fig. 11, the sealing member 5 is constructed in a boss structure including a first waterproof portion 53 and a second waterproof portion 54 coaxially disposed, the first waterproof portion 53 having an outer diameter larger than that of the second waterproof portion 54, the first waterproof portion 53 being embedded in the water receiving groove 42, the second waterproof portion 54 being disposed protruding from the water receiving groove 42 in the axial direction of the pin 3. Through setting up sealing member 5 to boss structure, during injection molding, compare in the unchangeable cylindrical sealing member 5 of external diameter, under the same prerequisite of injection molding material volume, can further pull out the height of sealing member 5 to make sealing member 5 satisfy the high demand, guarantee the manger plate effect of sealing member 5.

It is to be understood that the above examples of the present utility model are provided for clarity of illustration only and are not limiting of the embodiments of the present utility model. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the utility model are desired to be protected by the following claims.

Claims (10)

1. An electromagnetic coil, comprising:

the coil assembly comprises a shell (1) and a coil assembly (2), wherein the shell (1) is wrapped outside the coil assembly (2);

the two contact pins (3) are arranged at intervals and are connected with the coil assembly (2);

the plug-in shell (4) is arranged on one side of the shell (1), a plug-in port (41) is formed in the plug-in shell (4), the two plug pins (3) penetrate through the plug-in shell (4) and at least partially extend into the plug-in port (41), a water containing groove (42) is formed in the bottom surface (411) of the plug-in port (41), and the Rong Shuicao (42) are respectively arranged around the two plug pins (3).

2. The electromagnetic coil as set forth in claim 1, further comprising a sealing member (5), the sealing member (5) being embedded in the Rong Shuicao (42) and protruding from the Rong Shuicao (42) in an axial direction of the pins (3), the sealing member (5) being configured to seal the Rong Shuicao (42) and block the two pins (3).

3. The electromagnetic coil as set forth in claim 2, wherein the Rong Shuicao (42) is spaced from the pin (3).

4. A solenoid according to claim 3 characterised in that said Rong Shuicao (42) is configured in a "sun" shaped structure comprising an annular groove (421) and a straight groove (422), said annular groove (421) being circumferentially arranged along the peripheral edge of said plug-in interface (41), said straight groove (422) being located between two of said pins (3) and communicating with said annular groove (421) at both ends thereof;

the sealing element (5) is also constructed into a 'sun' shaped structure and comprises an annular part (51) and a blocking part (52), wherein the annular part (51) is embedded in the annular groove (421), the blocking part (52) is embedded in the straight groove (422) and two ends of the blocking part are respectively connected with the annular part (51), and the blocking part (52) protrudes out of the Rong Shuicao (42) along the axial direction of the contact pin (3) so as to separate the two contact pins (3).

5. The electromagnetic coil as set forth in claim 2, wherein the number of the Rong Shuicao (42) is two, the two Rong Shuicao (42) are arranged at intervals, the two Rong Shuicao (42) are respectively arranged around the corresponding pins (3), and the Rong Shuicao (42) is communicated with the surface of the pins (3);

the number of the sealing elements (5) is two, the two sealing elements (5) are respectively embedded in the corresponding Rong Shuicao (42), and the sealing elements (5) are sleeved outside the contact pin (3) and are in interference fit with the contact pin (3).

6. The electromagnetic coil as set forth in claim 5, wherein the seal member (5) is configured as a boss structure including a first waterproof portion (53) and a second waterproof portion (54) coaxially provided, the first waterproof portion (53) having an outer diameter larger than an outer diameter of the second waterproof portion (54), the first waterproof portion (53) being embedded in the Rong Shuicao (42), the second waterproof portion (54) being provided protruding from the Rong Shuicao (42) in an axial direction of the pin (3).

7. Electromagnetic coil according to any one of claims 2-6, characterized in that the seal (5) is made of rubber material.

8. Electromagnetic coil according to any one of claims 2 to 6, characterized in that the seal (5) is integrally formed with the plug housing (4).

9. Electromagnetic coil according to claim 1, characterized in that the housing (1) and the plug housing (4) are of integrally formed construction and are produced by means of a plastic-coating process.

10. The electromagnetic coil as set forth in claim 1, wherein the coil assembly (2) includes an enamel wire (21) and a coil bobbin (22), the two pins (3) are disposed at intervals and are both fixed on the coil bobbin (22), and the enamel wire (21) is wound on the coil bobbin (22) and has both ends respectively connected with the corresponding pins (3).