Manufacturing method of water temperature sensor

Abstract

The invention discloses a manufacturing method of a water temperature sensor, which comprises the following steps of: firstly, electrically connecting a thermistor with a terminal, then coating the thermistor and at least part of the terminal by adopting an insulating heat-conducting material to form a shell, and forming a connector at the first end of the shell, wherein the first end refers to one end far away from the thermistor. The shell is made of an insulating heat-conducting material and completely covers the thermistor, so that the problem of short circuit possibly occurring when the metal shell is in contact with the thermistor is avoided. In addition, the shell is integrally formed, dispensing heat conduction can be omitted, and therefore the installation angle of the thermistor does not need to be limited in the manufacturing process, the process can be effectively simplified, the operation difficulty can be effectively lowered, and the manufacturing efficiency can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature sensors, and in particular to a method for manufacturing a water temperature sensor. Background Art

[0002] The water temperature sensor is generally installed on the engine water outlet, mainly used to detect the temperature of the engine water outlet. Most water temperature sensors are thermistors of negative temperature systems. The higher the water temperature, the smaller the sensor resistance. Based on this change, the electronic control unit can measure the temperature of the engine cooling water, which is then used as a correction number for fuel injection and ignition timing.

[0003] Existing water temperature sensors such as Figure 1a and Figure 1b As shown, it includes a metal shell 001, a thermistor 002 and a connector 003, wherein the connector is arranged at one end of the metal shell, and the connector includes a terminal 031. The metal shell is provided with an inner cavity, the tail of which is open, the thermistor is encapsulated in the inner cavity by an insulating heat-conductive material, the thermistor is provided with an extraction electrode, the extraction electrode is electrically connected to a temperature sensing signal lead, the temperature sensing signal lead extends out of the inner cavity and is connected to the terminal of the connector. The metal shell is connected, for example, by a threaded connection ( Figure 1a ) or snap( Figure 1b ) is connected to the water pipe in the form of a thermal switch. The thermistor of this type of water temperature sensor is coated in an insulating thermal conductive material, which is generally an epoxy potting glue.

[0004] In order to prevent the thermal conductive adhesive from remaining on the head of the thermistor, the installation angle requirements are relatively strict. On the other hand, after the water temperature sensor is used in alternating heat for a long time, the epoxy potting adhesive is easily peeled off from the inner cavity of the metal shell, affecting the temperature sensing performance. Summary of the invention

[0005] In view of some or all of the problems in the prior art, the present invention provides a method for manufacturing a water temperature sensor in a first aspect, comprising:

[0006] electrically connecting the thermistor to the terminals; and

[0007] The thermistor and at least part of the terminals are covered with insulating heat-conductive material to form a shell, wherein the first end of the shell forms a connector, and the first end refers to an end away from the thermistor.

[0008] Further, electrically connecting the thermistor to the terminal includes:

[0009] The lead electrodes of the thermistor are welded to the terminals.

[0010] Furthermore, the forming of the shell includes:

[0011] placing the terminals for electrical connection and thermistor in the mold;

[0012] injecting the heated and melted insulating thermally conductive material into the mold; and

[0013] Wait for a specified period of time to allow the insulating thermally conductive material to cool and solidify.

[0014] Furthermore, the insulating thermally conductive material includes: thermoplastic resin.

[0015] Furthermore, the insulating thermally conductive material is polyhexamethylene adipamide (PA66).

[0016] Furthermore, the first end of the mold is a stepped frustum, the second end is in the form of a socket, and the thermistor is placed at the first end.

[0017] Furthermore, the first end of the mold is a three-step stepped cone, and the diameter of the mold increases successively from the end, and the diameter of the second end of the mold is not greater than the maximum diameter of the first end.

[0018] Furthermore, a first protrusion is provided at a position of the mold corresponding to the third-level truncated cone.

[0019] Furthermore, the manufacturing method further comprises:

[0020] A sealing ring is arranged at the first end of the housing.

[0021] Based on the manufacturing method described above, the second aspect of the present invention provides a water temperature sensor, which is manufactured using the method described above, and includes an integrally formed shell, a thermistor is enclosed inside the shell, and a portion of the terminal is exposed at one end of the shell away from the thermistor to form a connector, and the terminal is electrically connected to the thermistor.

[0022] The present invention provides a method for manufacturing a water temperature sensor, which forms a shell of the water temperature sensor through an integrated injection molding process, completely covers the thermistor, and avoids the short circuit problem that may occur when the metal shell contacts the thermistor. The use of an integrated injection-molded shell can also avoid the need for glue point heat conduction, so there is no need to limit the installation angle of the thermistor during manufacturing, which can effectively simplify the process, reduce the difficulty of operation, and improve manufacturing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] To further illustrate the above and other advantages and features of various embodiments of the present invention, a more specific description of various embodiments of the present invention will be presented with reference to the accompanying drawings. It will be understood that these drawings only depict typical embodiments of the present invention and are therefore not to be considered as limiting the scope thereof. In the accompanying drawings, for clarity, identical or corresponding parts will be represented by identical or similar reference numerals.

[0024] Figure 1a and 1b The structural schematic diagrams of water temperature sensors in the prior art are shown respectively;

[0025] Figure 2 A schematic flow chart showing a method for manufacturing a water temperature sensor according to an embodiment of the present invention;

[0026] Figure 3 A schematic diagram showing the structure of a water temperature sensor according to an embodiment of the present invention; and

[0027] Figure 4 A schematic diagram showing a water temperature sensor installed on a water pipe according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In the following description, the present invention is described with reference to various embodiments. However, those skilled in the art will recognize that various embodiments can be implemented without one or more specific details or with other replacement and / or additional methods, materials or components. In other cases, well-known structures, materials or operations are not shown or described in detail to avoid blurring the inventive point of the present invention. Similarly, for the purpose of explanation, specific quantities, materials and configurations are set forth to provide a comprehensive understanding of embodiments of the present invention. However, the present invention is not limited to these specific details. In addition, it should be understood that the various embodiments shown in the drawings are illustrative representations and are not necessarily drawn in correct proportions.

[0029] In this specification, reference to "one embodiment" or "the embodiment" means that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present invention. The phrase "in one embodiment" appearing in various places in this specification does not necessarily all refer to the same embodiment.

[0030] It should be noted that the embodiments of the present invention describe the process steps in a specific order, but this is only for the purpose of illustrating the specific embodiment, rather than limiting the order of the steps. On the contrary, in different embodiments of the present invention, the order of the steps can be adjusted according to the adjustment of the process.

[0031] The water temperature sensor usually includes a front seat connector and a rear seat metal shell, wherein the thermistor is arranged in the metal shell and is electrically connected to the connector. In order to avoid a short circuit caused by the contact between the thermistor and the metal shell, usually in the manufacturing process, the thermistor is inserted into the insulating material at a preset angle after the heat-conducting insulating material such as a heat-conducting material is placed in the metal shell. Such a method has high requirements for the installation angle. On the one hand, it is necessary to avoid the thermistor from penetrating the insulating material and contacting the metal shell, and on the other hand, it is necessary to avoid the backflow of the insulating material to ensure that the insulating material is always retained at the head of the thermistor, thereby avoiding the problem of excessive response time. In view of the above problems, in order to simplify the manufacturing process of the water temperature sensor and improve the manufacturing efficiency while ensuring the performance, the present invention provides a method for manufacturing a water temperature sensor, which can eliminate the connection process between the connector and the general metal shell. Specifically, the manufacturing method is to weld the thermistor to the terminal and then perform integral injection molding through a mold. The plastic particles can completely wrap the thermistor without leaving any gaps, which can meet the insulation requirements on the one hand and ensure its waterproof and dustproof performance at the same time. At the same time, the integral injection molding can be installed at any angle, which effectively reduces the difficulty of installation.

[0032] The technical solution of the present invention is further described below in conjunction with the accompanying drawings of the embodiments.

[0033] Figure 2 A schematic flow chart of a method for manufacturing a water temperature sensor according to an embodiment of the present invention is shown. Figure 2 As shown, a method for manufacturing a water temperature sensor comprises:

[0034] First, in step 201, the thermistor and the terminal are connected. The thermistor is electrically connected to the terminal. One end of the water temperature sensor includes a connector, which is used to realize the transmission of electricity and / or signals between the water temperature sensor and the external circuit. The connector usually consists of three parts: a contact, an insulator and a shell. The contact, which can also be called a terminal, is usually made of conductive metal material and is the core part of the connector to complete the electrical connection function. The insulator is used to isolate and fix the contact to ensure the stable transmission of current, and the shell provides physical protection and fixing. Generally speaking, the manufacture of the connector is to place the terminal in the cavity of the injection mold, then inject plastic into the cavity, cool and form it, and then take it out to form an insulator and / or shell. However, in the present invention, the entire shell of the water temperature sensor adopts an integrated molding process, so it is necessary to first realize the electrical connection of the internal structures of the water temperature sensor, that is, the electrical connection between the thermistor and the connector. Based on this, in one embodiment of the present invention, it is first necessary to weld the lead electrodes of the thermistor to the terminals one by one, and the terminals and the shell form the connector together. In one embodiment of the present invention, the thermistor may have two or more lead electrodes, and accordingly, the terminals may also be two or more. In one embodiment of the present invention, the terminals are made by stamping metal sheets; and

[0035] Next, in step 202, a shell is formed. As mentioned above, in an embodiment of the present invention, the shell is made by an integrated molding process, that is, an insulating thermally conductive material is used to cover the thermistor and at least part of the terminals to form the shell. As mentioned above, one end of the shell needs to be used as a connector to achieve electrical connection with an external circuit, so the insulating thermally conductive material does not completely cover the terminals, but exposes at least a portion of the terminals. Specifically, in one embodiment of the present invention, the insulating thermally conductive material can cover one end of each terminal close to the thermistor, thereby forming an insulator between the terminals for isolating and fixing each terminal. In another embodiment of the present invention, the insulating thermally conductive material can also form a cavity with an open upper end at the first end, so that the terminal is located in the cavity, thereby serving as a shell of a connector to protect the terminal, wherein the first end is to an end away from the thermistor.

[0036] In one embodiment of the present invention, the shell is made by an integrated injection molding process, which can be realized by an injection molding machine based on a mold of a specified shape. Based on this, the material of the shell is a thermoplastic resin, for example, polyhexamethylene adipamide (PA66) can be used. In one embodiment of the present invention, the shell is manufactured by an integrated injection molding process, and first, the terminals and thermistors that have been electrically connected need to be placed in the mold. In this process, in order to avoid the terminals and thermistors being distorted under the subsequent injection molding pressure, ejector pins or other positioning members can be set in the mold to fix the terminals and thermistors. Next, the insulating thermally conductive material that has been heated and melted is injected into the mold with a certain pressure, so that the liquid insulating thermally conductive material completely covers the thermistor, and the terminal is close to one end of the thermistor, and finally the insulating thermally conductive material is cooled and solidified, and it is taken out of the mold to complete the manufacture of the water temperature sensor. In some embodiments of the present invention, further processes such as deburring and polishing can be performed.

[0037] In order to achieve better performance, it is necessary to define the shell shape of the water temperature sensor. For example, in order to improve the sensitivity, the thickness of the insulating thermal conductive material covering the thermistor body should not be too large, and the thickness of the insulating thermal conductive material can be increased accordingly for the rest of the parts to provide better protection. For another example, the water temperature sensor is usually installed on a water pipe. In order to adapt to the pipe interface, the shell of the water temperature sensor also needs to be provided with a certain fixed structure, such as a threaded structure, a slot, etc. For another example, in order to improve the waterproof and dustproof level, the shell should also be provided with a corresponding sealing structure. The characteristics of the shell can be defined by the shape of the mold. In one embodiment of the present invention, a mold for manufacturing a water temperature sensor includes a first part, a middle part and a second part, wherein the first part refers to the part where the thermistor is placed, the second part refers to the part where the terminal is placed, and the middle part is located between the first part and the second part. In one embodiment of the present invention, the first part is a stepped truncated cone, specifically, the top end, that is, the diameter of the part where the thermistor body is placed is smaller than the rest. In one embodiment of the present invention, in order to adapt to the structure of the water pipe, the first end may also be a three-step stepped cone, and the diameter of the mold increases successively from the end. In order to facilitate fixation, in one embodiment of the present invention, a first protrusion is provided at the middle part and / or the first part of the mold, so that a card slot can be formed in the middle part of the shell made based on the mold to facilitate the installation of the buckle, etc. There is no restriction on the diameter of the second part of the mold, for example, it can be smaller than the diameter of the third stage of the three-step stepped cone, and / or equal to the diameter of the second stage of the three-step stepped cone, etc., but its end is in the form of a connector. Specifically, it includes, for example, a component covering the terminal, so that there is a certain gap between the terminals after the final molding, and / or has a connector of a specified shape, etc.

[0038] In one embodiment of the present invention, in order to further improve the waterproof and dustproof performance, a sealing structure may be provided outside the shell, for example, a sealing ring may be sleeved outside the first end of the shell.

[0039] Based on the manufacturing method described above, Figure 3 FIG. 2 is a schematic diagram showing the structure of a water temperature sensor according to an embodiment of the present invention. Figure 3 As shown, a water temperature sensor includes a thermistor 301, a terminal 302 and a shell 303, wherein the lead electrode 311 of the thermistor 301 is electrically connected to the first end of the terminal 302, and the shell 303 is made by an integrated molding process, completely covering the thermistor while exposing the second end of the terminal to form a connector.

[0040] like Figure 3 As shown, the first end of the shell, that is, the end where the thermistor is located, is in a stepped truncated cone shape. Specifically, the diameter of the shell covering the thermistor body is smaller than the diameter of the other parts of the shell. Figure 3 As shown, the middle part of the housing includes a protrusion 331 to facilitate snapping on the water pipe interface. At the same time, a card slot 332 is provided on the protrusion. When the water temperature sensor is installed on the water pipe interface, a buckle 401 can be provided at the card slot to better fix the water temperature sensor. Figure 4 As shown. Figure 3 As shown, the second end of the housing is in the form of a socket. Specifically, the second end includes a cavity 333 with an upper opening. The second end of the terminal 302 is located in the cavity and can be electrically connected to an external circuit by plugging or welding. Figure 3 As shown, in one embodiment of the present invention, the outer surface of the second end of the housing is provided with a card interface 334. In one embodiment of the present invention, the outer surface of the first end of the housing is also provided with a sealing structure, such as a sealing ring 402.

[0041] The water temperature sensor can be applied to a liquid temperature control circulation system, for example, to monitor and feedback water temperature information in real time.

[0042] The present invention provides a method for manufacturing a water temperature sensor, which forms a shell of the water temperature sensor through an integrated injection molding process, completely covers the thermistor, and avoids the short circuit problem that may occur when the metal shell contacts the thermistor. The use of an integrated injection-molded shell can also avoid the need for glue point heat conduction, so there is no need to limit the installation angle of the thermistor during manufacturing, which can effectively simplify the process, reduce the difficulty of operation, and improve manufacturing efficiency.

[0043] Although various embodiments of the present invention are described above, it should be understood that they are presented as examples only and not as limitations. It is obvious to those skilled in the relevant art that various combinations, modifications and changes can be made thereto without departing from the spirit and scope of the present invention. Therefore, the breadth and scope of the present invention disclosed herein should not be limited by the exemplary embodiments disclosed above, but should only be defined according to the attached claims and their equivalents.

Claims

1. A method for manufacturing a water temperature sensor, characterized in that: Includes steps: Electrically connect the thermistor to the terminals; as well as The thermistor and at least part of the terminals are covered with insulating heat-conductive material to form a shell, wherein the first end of the shell forms a connector, and the first end refers to an end away from the thermistor.

2. The manufacturing method according to claim 1, characterized in that Electrically connecting the thermistor to the terminals comprises the steps of: The lead electrodes of the thermistor are welded to the terminals.

3. The manufacturing method according to claim 1, characterized in that: The insulating heat-conductive material includes: thermoplastic resin.

4. The manufacturing method according to claim 1, characterized in that: The insulating heat-conducting material is polyhexamethylene adipamide.

5. The manufacturing method according to claim 1, characterized in that: The shell is made by an integral injection molding process.

6. The manufacturing method according to claim 1, characterized in that: The formation of the shell comprises the steps of: placing the terminals for electrical connection and thermistor in the mold; injecting the heated and melted insulating thermally conductive material into the mold; as well as Wait for a specified period of time to allow the insulating thermally conductive material to cool and solidify, and then remove it from the mold.

7. The manufacturing method according to claim 6, characterized in that: The first end of the mold is a stepped frustum, the second end is a socket, and the thermistor is placed at the first end.

8. The manufacturing method according to claim 6, characterized in that: The first end of the mold is a three-step stepped frustum, and the diameter of the mold increases successively from the end, and the diameter of the second end of the mold is not greater than the maximum diameter of the first end.

9. The manufacturing method according to claim 6, characterized in that: A first protrusion is arranged in the middle of the mold.

10. The manufacturing method according to claim 1, characterized in that: The manufacturing method further comprises the steps of: A sealing ring is arranged at the first end of the housing.

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