Electronic component and method for manufacturing the same

Abstract

To provide a technology that enables miniaturization of electronic components.SOLUTION: An electronic component comprises a substrate with components joined by the solder, a coating to cover the solder, and a coating section that covers the substrate and the coating and consists of a thermoplastic resin having a melting point higher than the melting point of the solder.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to electronic components and manufacturing methods.

Background Art

[0002] Conventionally, electronic components controlled by circuit components on a substrate have been known. For example, Patent Document 1 discloses a fluid pump controlled by circuit components on a substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the prior art, a motor housing including a motor or the like and a driver unit including a substrate are connected, and the substrate is fixed to the pedestal of the driver unit with screws. Further, if the substrate is exposed without a cover, it is likely to cause a failure of the electronic component. Therefore, in many cases, the substrate is housed in a housing. Although fixing with screws is a simple method, generally, a plurality of screws are required, and a portion for fixing the screws on the substrate is also required. In addition, a space corresponding to the length and width of the screws is required. For this reason, when fixing with screws is adopted, it is difficult to miniaturize the electronic component. Further, in order to adopt a structure in which the substrate is housed in a housing, it is necessary to design the housing so that a space including the substrate is formed, and it is difficult to miniaturize the housing including the substrate.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a technology capable of miniaturizing electronic components.

Means for Solving the Problems

[0006] To achieve the above object, an electronic component includes a substrate to which components are joined by solder, a coating that covers the solder, and a covering portion made of a thermoplastic resin that covers the substrate and the coating and has a melting point higher than the melting point of the solder.

[0007] That is, in an electronic component, a substrate to which components are joined by solder is covered with a thermoplastic resin. Since the thermoplastic resin has a melting point higher than the melting point of the solder, if the thermoplastic resin is melted to form a covering portion in a state where the solder and the thermoplastic resin are in contact, the solder may melt. However, since the solder is coated, heat conduction from the melted thermoplastic resin to the solder can be reduced, and the possibility of the solder remelting can be reduced.

[0008] With this configuration, the substrate can be covered without using screws to fix it to the housing. Therefore, the substrate can be protected by the covering portion without providing a structure for screw fixation on the substrate. For this reason, it is possible to easily miniaturize the electronic component as compared with the case of providing a space for screw fixation.

Brief Description of the Drawings

[0009]

Figure 1

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Figure 9

Embodiments for Carrying Out the Invention

[0010] Here, embodiments of the present invention will be described in the following order. (1) Configuration of the electronic component: (2) Method for manufacturing the electronic component: (3) Other embodiments:

[0011] (1) Configuration of the electronic component: Figure 1A is a plan view showing the electronic component 1, Figure 1B is a left side view showing the electronic component 1, and Figure 1C is a front view showing the electronic component 1. Figure 2A is a perspective view of the electronic component 1 seen obliquely. In this specification, for the sake of explanation, the up, down, front, back, left, and right of the electronic component 1 are defined as shown in Figure 2A for convenience. In Figure 1A, the front and back of the electronic component 1 are arranged on the right and left, and the left and right are arranged on the up and down, and the electronic component 1 is shown in this state. In Figure 1B, the up and down of the electronic component 1 are arranged on the right and left, and the left and right are arranged on the up and down, and the electronic component 1 is shown in this state. In Figure 1C, the up and down of the electronic component 1 are arranged on the up and down, and the front and back are arranged on the right and left, and the electronic component 1 is shown in this state. Also, in Figure 1C, the substrate 10 provided inside the electronic component 1 and the surrounding structure are shown in a state where they are made transparent.

[0012] The electronic component 1 includes a covering portion 20 that constitutes most of the outer surface of the electronic component 1. The covering portion 20 covers the substrate 10, and the substrate 10 is not exposed to the outside. In the present embodiment, the electronic component 1 is a rotation sensor using a Hall element as a sensor element.

[0013] The shape of the covering portion 20 is not limited to the shape of the covering portion 20 according to the present embodiment. However, since the electronic component 1 is a rotation sensor in the present embodiment, the covering portion 20 is formed into a shape for causing the electronic component 1 to function as a rotation sensor. Specifically, a window portion 21 and a connector connection portion 22 are formed in the covering portion 20.

[0014] The window portion 21 is a cylindrical hole extending in the vertical direction, formed at the center of the upper surface of the covering portion 20. The upper part of the window portion 21 is open, and below it, there are a spacer 15 and the covering portion 20 to be described later, and it is not open. That is, one surface of the spacer 15 is exposed below the window portion 21, the covering portion 20 exists around the spacer 15, and the exposed surface of the spacer 15 and the surface 21a of the covering portion 20 form the same surface perpendicular to the vertical direction.

[0015] In the present embodiment, a magnet is attached to a detection object to be detected for rotation by a rotation sensor. The electronic component 1 is fixed and used at a position where the magnet of the detection object passes above the window portion 21. A substrate 10 is disposed below the spacer 15, and a Hall element 11 is mounted on the substrate 10 (see FIG. 1C). Therefore, when the magnet passes above the window portion 21, a signal is output from the Hall element 11 indicating the passage of the magnet.

[0016] Terminals 12 to be described later are attached to the substrate 10. The Hall element 11 receives the supply of the drive voltage of the Hall element 11 from an external device via the terminal 12 and outputs the signal output from the Hall element 11 to the external device. A plurality of terminals 12 are attached to the substrate 10 and extend in the front-rear direction.

[0017] The connector connection part 22 is a cylindrical hole that protrudes forward in the covering part 20. The front of the connector connection part 22 is open, and the rear is closed by the covering part 20. However, the front end part 12a of the above-mentioned terminal 12 is arranged in the inner space 22a of the connector connection part 22. The connector connection part 22 is a part where a connector having a shape slightly smaller than the inner circumference of the inner space 22a is connected. That is, when the connector connected to the external device is inserted into the connector connection part 22, the hall element 11 on the substrate and the external device are electrically connected, and it becomes possible to detect the rotation of the detection object by the external device.

[0018] Figures 3A to 3C are diagrams showing the substrate 10 included in the electronic component 1 taken out. Figure 3A is a plan view showing the substrate 10, Figure 3B is a left side view showing the substrate 10, and Figure 3C is a front view showing the substrate 10. Figure 2B is a perspective view of the substrate 10 seen obliquely. In this specification, for the sake of explanation, the up, down, front, rear, left, and right of the electronic component 1 shown in Figure 2A are defined as the up, down, front, rear, left, and right of the substrate 10. In Figure 3A, the front and rear of the substrate 10 are arranged on the right and left, and the substrate 10 is shown in a state where the left and right are arranged vertically. In Figure 3B, the up and down of the substrate 10 are arranged on the right and left, and the substrate 10 is shown in a state where the left and right are arranged vertically. In Figure 3C, the up and down of the substrate 10 are arranged vertically, and the substrate 10 is shown in a state where the front and rear are arranged on the right and left.

[0019] The substrate 10 is a rectangular parallelepiped, and the surface perpendicular to the up and down direction is the largest. The substrate 10 is a printed circuit board on which printed wiring (not shown) is formed on the largest surface. In the substrate 10, a part of the printed wiring is formed as pads, and the parts other than the pads are covered with an insulator. The pads are parts where components are electrically joined, and in this embodiment, the components are mounted on the substrate 10 by solder.

[0020] In the substrate 10 shown in FIGS. 3A to 3C, the components include a Hall element 11 and a terminal 12. The Hall element is a chip with multiple terminals, and is soldered to approximately the center of the mounting surface of the substrate 10. In this embodiment, there are a total of six terminals 12, and the six terminals 12 are soldered to a position near the front of the substrate 10 so that they are lined up in the left-right direction along the front side edge. In this embodiment, the terminals 12 are in the shape of a thin plate, long in the front-rear direction and short in the left-right direction. The terminals 12 are mounted on the substrate 10 so as to extend from the rear to the front. The terminals 12 are bent at approximately 90° at two points in the longitudinal direction, and the portion near the end including the front end 12a of the terminals 12 is shorter in the left-right direction than the other portions, but the terminals 12 as a whole have an elongated shape extending in the front-rear direction.

[0021] In this embodiment, the covering portion 20 is made of a thermoplastic resin, and the substrate 10 is also molded integrally when the covering portion 20 is molded. Therefore, a spacer 15 is used so that the position of the substrate 10 is positioned in the mold of the covering portion 20 during molding. Figures 4A to 4C are diagrams showing a state in which the spacer 15 is attached to the substrate 10 shown in Figures 3A to 3C. Figure 4A is a plan view showing the substrate 10 to which the spacer 15 is attached, Figure 4B is a left side view showing the substrate 10 to which the spacer 15 is attached, and Figure 4C is a front view showing the substrate 10 to which the spacer 15 is attached. Figure 2C is a perspective view of the substrate 10 to which the spacer 15 is attached, seen obliquely. Up, down, front, back, left and right in Figures 4A to 4C are defined in the same way as in Figures 1A to 1C and Figures 3A to 3C.

[0022] The spacer 15 has a shape like a hollow hexahedron with one face opened, and the opened face is attached to the component mounting surface of the substrate 10. In the present embodiment, the spacers 15 are attached to the mounting surfaces above and below the substrate 10 respectively. A hall element 11 is accommodated inside one of the spacers 15. Bellows-shaped buffer portions 15a are formed on the side surfaces of the spacer 15, that is, the front, rear, left, and right surfaces in FIG. 4A. With this configuration, for example, it is possible to prevent the substrate 10 from being damaged by the force acting when the mold contacts the spacer 15.

[0023] When the substrate 10 and the covering portion 20 are integrally formed, the spacers 15 are attached to the substrate 10 in advance. Therefore, the covering portion 20 and the hall element 11 do not come into contact. Also, the upper and lower surfaces of the spacer 15 are in contact with the planes formed on the mold used for molding. Therefore, the upper and lower surfaces of the spacer 15 can be exposed outside the covering portion 20. In FIGS. 1A and 2A, the state where the exposed surface of the spacer 15 and the surface 21a of the covering portion 20 are visible from above the window portion 21 is shown.

[0024] In the present embodiment, as described above, the covering portion 20 and the hall element 11 do not come into contact. That is, viewed from the thermoplastic resin constituting the covering portion 20, the solder for mounting the hall element 11 is isolated. However, the covering portion 20 and the terminal 12 are in contact. Such a configuration is realized by injecting a thermoplastic resin into a mold (not shown) for molding the covering portion 20 with the substrate 10 shown in FIGS. 4A to 4C placed in the mold, and molding the covering portion 20.

[0025] As shown in FIGS. 1A, 1C, 2A, etc., the substrate 10 is covered by the covering portion 20. Although the terminal 12 is partially exposed inside the connector connection portion 22, the other portions are covered by the covering portion 20. Therefore, the joint portion between the terminal 12 and the substrate 10 is covered by the covering portion 20 together with the solder. In the present embodiment, the thermoplastic resin constituting the covering portion 20 is polybutylene terephthalate (PBT), which has a melting point of 224° C. and is molded at 260° C. On the other hand, the solder for joining the terminal 12 to the substrate 10 has a melting point of 217° C. Therefore, the thermoplastic resin constituting the covering portion 20 has a melting point higher than that of the solder.

[0026] Therefore, when molding the covering portion 20, if the thermoplastic resin comes into contact with the solder joining the terminal 12 to the substrate 10, the solder may remelt. Thus, in the present embodiment, the solder is coated so that the solder does not directly contact the thermoplastic resin. FIG. 5 is a cross-sectional view showing an enlarged joint portion of the terminal 12 with respect to the substrate 10. FIG. 5 shows a state in which the terminal 12 on the substrate 10 is cut in a direction perpendicular to the left-right direction. Also, FIG. 5 shows a state after the covering portion 20 is molded, and the covering portion 20 is also shown in a state of being cut in the same cross-section as the terminal 12.

[0027] At the portion where the terminal 12 and the substrate 10 are joined, solder 13 exists along the outer peripheral surface of the terminal 12. The solder 13 is formed, for example, by joining the terminal 12 and the substrate 10 using a reflow furnace. In the present embodiment, a coating 14 is formed over a range wider than the solder 13 around the solder 13. That is, the solder 13 is covered by the coating 14 so that the solder 13 formed on the terminal 12 does not contact the thermoplastic resin of the integrally molded covering portion 20. Therefore, it is possible to prevent the thermoplastic resin, which has a melting point higher than that of the solder 13 and is molded at a temperature higher than the melting point of the solder 13, from contacting the solder 13.

[0028] In this embodiment, the coating 14 includes a resin for coating and particles having a lower thermal conductivity than the resin for coating. That is, the coating 14 contains a plurality of particles, and the thermal conductivity of each particle is smaller than that of the resin for coating existing around each particle. Therefore, it is possible to reduce the possibility that the coating 14 conducts heat from the thermoplastic resin to the solder 13 and the solder 13 remelts.

[0029] In this embodiment, the resin for coating is an ultraviolet curable resin. If an ultraviolet curable resin is used as the resin for coating, after the solder 13 is coated with the coating 14, the coating 14 can be cured by irradiating the coating 14 with ultraviolet rays.

[0030] Also, as long as the particles contained in the coating 14 have a lower thermal conductivity than the resin for coating and can reduce the possibility that heat is conducted from the thermoplastic resin to the solder 13 and the solder 13 remelts. Therefore, the particle structure, average particle size, mixing viscosity of the particles, etc. can be various values. For example, it is possible to assume an example in which the coating 14 contains particles having a hollow particle structure, an average particle size of 20 μm, and a mixing viscosity of the particles of 2700 mPa·s.

[0031] Also, the thickness of the layer of the coating 14 is preferably equal to or greater than the average particle size of the particles. According to this configuration, in the layer thickness direction within the coating 14, the thickness is such that one or more particles can exist. Therefore, compared with the coating 14 having a thickness thinner than the average particle size of the particles, it is possible to more reliably suppress heat conduction by the particles. Note that the thickness of the layer of the coating 14 is not limited. For example, when the average particle size of the particles is 40 μm, a configuration in which the layer thickness is 600 μm can be adopted. Also, the average particle size of the particles may be selected, for example, from the range of 20 to 50 μm, and the layer thickness may be selected, for example, from the range of 100 μm to 1000 μm.

[0032] As shown in FIG. 3A and the like, in the present embodiment, each of the plurality of terminals 12 on the substrate 10 is mounted by solder 13. Therefore, there are a plurality of solders 13 corresponding to each of the plurality of terminals 12, and the coating 14 covers each of the solders 13 of the plurality of terminals 12. However, in the present embodiment, the solder for mounting the Hall element 11 on the substrate 10 is covered by the spacer 15 and does not contact the thermoplastic resin (that is, it is isolated), so it does not have to be coated with the coating 14. That is, the coating 14 does not have to cover each of the solders isolated from the thermoplastic resin. According to this configuration, the amount of the coating 14 material used can be reduced as compared with the configuration of coating the solder for mounting the Hall element 11 on the substrate 10.

[0033] (2) Method for manufacturing an electronic component: FIG. 6 is a flowchart showing a method for manufacturing an electronic component. When manufacturing an electronic component, first, components are mounted on a substrate (step S100). Specifically, a substrate 10 on which printed wiring for realizing a pre-designed circuit is formed is prepared. Also, each component for realizing a pre-designed circuit is mounted on the substrate 10 by solder. For the electronic component 1 shown in FIGS. 1A, 3A, 4A, etc. above, the Hall element 11 and the terminal 12 are soldered to the substrate 10 by reflow or the like. The state after soldering is, for example, the state shown in FIGS. 3A to 3C.

[0034] Next, a coating resin and particles are mixed (step S105). That is, a coating resin in a liquid state at room temperature is prepared in a container, and a predetermined amount of particles is put into the container and mixed.

[0035] Next, the substrate is dipped in a coating agent (step S110). That is, the substrate is immersed in the coating agent prepared in step S105. At this time, if the coating 14 does not exist, the immersion is performed so that the solder at the position where it will come into contact with the thermoplastic resin of the coated portion 20 is immersed in the coating agent.

[0036] Next, ultraviolet rays are irradiated (step S115). That is, after the substrate is taken out of the coating agent, ultraviolet rays are irradiated onto the coating agent. In the case of the electronic component 1 shown in FIGS. 1A, 3A, 4A, etc. described above, ultraviolet rays are irradiated onto the coating agent covering the solder 13 of the terminal 12. The state after the coating 14 is formed is, for example, the state shown in FIGS. 4A to 4C.

[0037] Next, a spacer is attached (step S120). That is, in order to set the position of the substrate within the covering portion and the position of the substrate within the mold to predetermined positions, a spacer is attached to the substrate. In the case of the electronic component 1 shown in FIGS. 1A, 3A, 4A, etc. described above, spacers 15 are attached to both surfaces of the substrate 10. The state after the spacers 15 are attached is, for example, the state shown in FIGS. 4A to 4C.

[0038] Next, integral molding is performed (step S125). That is, the substrate with the spacer attached is set in the mold, and the thermoplastic resin is injected into the mold. As a result, the space around the substrate is filled with the thermoplastic resin, and the substrate and the covering portion are integrally molded. In the case of the electronic component 1 shown in FIGS. 1A, 3A, 4A, etc. described above, the substrate 10 with the spacers 15 attached is set in the mold, and integral molding is performed. The state after the covering portion 20 is formed by integral molding is, for example, the state shown in FIGS. 1A to 1C.

[0039] Through the above steps, the substrate 10 and the coating 14 are coated by the coating portion 20, and the electronic component 1 with a part of the terminal 12 exposed is manufactured. According to the above configuration, when integral molding is performed, the possibility of the solder 13 on the substrate 10 being remelted by the heat from the molten thermoplastic resin can be reduced. With this configuration, the substrate 10 can be coated without using screws to fix it to the housing. Therefore, there is no need to provide a structure for screw fixation on the substrate 10, and the substrate 10 can be protected. For this reason, the electronic component 1 can be miniaturized. Also, since there is no need to use screws to fix the substrate 10, the number of parts and the manufacturing man-hours can be reduced. Furthermore,

[0040] (3) Other embodiments: The above embodiments are examples for implementing the present invention, and various other embodiments can also be adopted. For example, the electronic component only needs to include a substrate, a coating, and a coating portion, and the use of the electronic component is not limited. Also, parts other than the substrate may be integrally molded with the substrate to form the coating portion.

[0041] Figs. 7 to 9 are diagrams showing an example in which an electric pump including a motor controlled by a substrate is an electronic component according to an embodiment. Fig. 7 is a flowchart showing a manufacturing method of the electronic component. Figs. 8A to 8H and Figs. 9A to 9C are diagrams for explaining each step.

[0042] Also in this embodiment, when manufacturing the electronic component, first, the parts are mounted on the substrate (step S200). Specifically, a substrate 100 on which a printed wiring for realizing a circuit for controlling the motor is formed is prepared, and each circuit component for realizing the circuit is mounted on the substrate 10 with solder. Each circuit component is soldered, for example, by reflow or the like. Fig. 8A is a diagram showing the substrate 100 after soldering.

[0043] Next, an insulator and a coil are attached to the stator core (step S202). In the present embodiment, a part of the substrate 100 and the motor components are integrally formed with the coating portion. Therefore, motor components to be integrally formed are prepared. In the present embodiment, the motor components to be integrally formed include a stator core, an insulator, and a coil.

[0044] In the present embodiment, the motor includes a rotor and a stator core. The rotor is a component that rotates around the rotation axis. In the present embodiment, the rotor is not an object to be integrally formed with the substrate 100. Here, the direction parallel to the rotation axis of the rotor is called the axial direction, the direction perpendicular to the axial direction is called the radial direction, and the rotation direction with respect to the rotation axis is called the circumferential direction. Also, the direction facing the rotation axis in the radial direction is called the inner radial direction, and the direction facing the opposite direction to the rotation axis in the radial direction is called the outer radial direction.

[0045] FIG. 8C and FIG. 8D are views showing the stator core 110 to which the insulator 112 and the coil 114 are attached. FIG. 8C shows a state of viewing the stator core 110 along the radial direction, and FIG. 8D shows a state of viewing the stator core 110 from an oblique direction. The stator core 110 is a component fixed to a motor case or the like. The configuration of the stator core 110 is not limited, but in the present embodiment, the stator core 110 is an annular component existing outside the rotor in the circumferential direction. A plurality of stator teeth protruding radially inward are formed on the inner side in the radial direction of the annular stator core 110. In the circumferential direction, the space between the plurality of stator teeth is a slot, which forms a space in which the coil is wound.

[0046] The insulator 112 is a component that sandwiches the stator teeth from both axial sides and is a member for insulating the stator core 110 and the coil 114. The coil 114 is wound around the stator teeth to which the insulator 112 is attached, routed radially outside the insulator 112, and connected to the substrate 100. Note that the insulator 112 is provided with terminals and the like for routing the wiring extending from the coil 114 to the substrate 100. In step S202, as shown in FIGS. 8C and 8D above, the insulator 112 is attached to the stator core 110, and further, the coil 114 is wound.

[0047] Next, a spacer is attached (step S205). In the present embodiment, in order to set the position of the substrate 100 within the covering portion and the position of the substrate 100 within the mold to predetermined positions, and to set the position of the terminals joined to the substrate 100 to a predetermined position, the spacer 150 is attached to the stator core 110. FIG. 8B shows an example of the spacer 150. The spacer 150 may have an arbitrary shape as long as it can set the positions of the substrate 100 and the terminals to predetermined positions.

[0048] FIG. 8E shows an example in which the spacer 150 is attached to the stator core 110. Note that the perspective view shown in FIG. 8F shows the terminal 120, but the spacer 150 is in an omitted state. As shown in FIG. 8F, in a state where the substrate 100 does not exist, in a part of the terminal 120, there is no pedestal or the like for attaching the terminal 120, so positioning is performed by attaching the terminal 120 to the spacer 150. Note that the terminal 120 shown in the upper right part of FIG. 8E is a terminal for connecting a connector, similar to the terminal 12 shown in FIG. 3. A part of it is covered by the covering portion 200 described later, and the remaining part is not covered by the covering portion 200 and is in an exposed state.

[0049] Next, the substrate 100 is assembled (step S207). That is, the spacer 150 is formed with a structure (for example, an engaging portion, etc.) (not shown) to which the substrate 100 can be assembled, and the substrate 100 is assembled to the spacer 150 using this structure. At this time, the terminal 120 is also configured to be in a predetermined position with respect to the substrate 100. In the present embodiment, one end of the terminal 120 penetrates through a hole previously formed in the substrate 100.

[0050] FIG. 8G shows an example in which the substrate 100 is attached to the spacer 150. As shown in FIG. 8G, the substrate 100 is positioned by the spacer 150. Note that the perspective view shown in FIG. 8H shows the substrate 100, but the spacer 150 is omitted.

[0051] Next, the substrate and the terminal are soldered (step S208). That is, in step S207, the end portion of the terminal 120 protruding from one surface of the substrate 100 is joined to the substrate 100 with solder.

[0052] Next, the coating resin and the particles are mixed (step S210). That is, a coating resin in a liquid state at room temperature is prepared in a container, and a predetermined amount of particles is put into the container and mixed.

[0053] Next, the substrate is dipped in the coating agent (step S215). That is, the substrate is immersed in the coating agent prepared in step S210. FIG. 9A is a diagram for explaining the immersion. In step S210, the substrate 100 is moved downward with respect to the container V in which the coating agent C is accumulated to coat the solder on the substrate 100. Note that in the present embodiment, the immersion is performed so that all of the solder used for joining the components to the substrate 100 is immersed in the coating agent.

[0054] Next, ultraviolet rays are irradiated (step S220). That is, after the substrate 100 is taken out of the container V, ultraviolet rays are irradiated onto the coating agent.

[0055] Next, integral molding is performed (step S225). That is, the stator core 110 to which the spacer 150 and the substrate 100 are attached is set in a mold, and a thermoplastic resin is injected into the mold. As a result, the space around the substrate 100 is filled with the thermoplastic resin, and the substrate 100 and the covering portion 200 are integrally molded. FIGS. 9B and 9C are views showing the covering portion 200 after integral molding. FIG. 9B shows a state in which the covering portion 200 is viewed along the radial direction of the stator core 110 in the covering portion 200, and FIG. 9C shows a state in which the covering portion 200 is viewed from an oblique direction. Through the above steps, the covering portion 200 covers the substrate 100, the solder coating for mounting components on the substrate 100, the stator core 110, the insulator 112, the coil 114, and a part of the terminal 120, and an electronic component in which the remaining part of the terminal 120 is exposed is manufactured.

[0056] Even in the above configuration, when integral molding is performed, it is possible to reduce the possibility that the solder on the substrate 100 is remelted by the heat from the molten thermoplastic resin. With this configuration, the substrate 100 can be covered without using screws to fix it to the housing, and the electronic component can be miniaturized. Further, since it is not necessary to use screws to fix the substrate 10, the number of parts and the manufacturing man-hours can be reduced.

[0057] The substrate may be any substrate to which components are joined by solder. That is, a circuit for exchanging various signals with other electronic components joined to the substrate is formed on the substrate. The circuit formed on the substrate is not limited, and may be a circuit for exchanging information with other electronic components, a circuit for controlling other electronic components, or a circuit controlled by other electronic components. The form of the components is also not limited, and components of various sizes, shapes, and types may be mounted on the substrate. The components only need to be joined to the substrate by solder and may be various components. For example, circuit components such as active elements and passive elements, integrated circuits, or terminals joined to other electronic components may be the components.

[0058] The coating only needs to be able to cover the solder. That is, the coating is a layer that protects the solder, and as long as it can be interposed between the solder and the thermoplastic resin so that the solder and the thermoplastic resin do not directly touch each other. And as long as the heat can be conducted from the molten thermoplastic resin to the solder through the interposition of the coating, reducing the possibility of the solder being remelted.

[0059] Note that the coating only needs to be able to conduct heat from the thermoplastic resin to the solder and reduce the possibility of the solder being remelted. Therefore, as long as this is the case, the material and thickness of the coating are not limited and can be realized in various states. Furthermore, since the coating is a layer for preventing contact between the thermoplastic resin and the solder, when there are components isolated from the thermoplastic resin on the substrate, the solder on those components does not necessarily need to be coated.

[0060] The covering portion may be any portion made of a thermoplastic resin that covers the substrate and the coating and has a melting point higher than the melting point of the solder. That is, the thermoplastic resin only needs to cover the substrate and can be manufactured, for example, by integrally molding the substrate with the thermoplastic resin.

[0061] Further, the covering part only needs to cover the coating on the components mounted on the substrate together with the substrate by covering the substrate. The covering part only needs to cover all or part of the substrate and the coating on the components so as not to be exposed to the outside. Components on the substrate that are not coated (for example, the terminals in the above-described embodiment) may be exposed outside the covering part. Also, even for components on the substrate, parts where no solder exists may be exposed outside the covering part.

[0062] The thermoplastic resin may be any resin that melts and becomes liquid when the temperature reaches or exceeds the melting point and becomes rubbery or glassy when the temperature is lower than the melting point. Also, since the melting point is higher than that of the solder, if the thermoplastic resin and the solder are in direct contact during molding, the solder may remelt. The melting point is not limited, but for example, an example where the melting point of the thermoplastic resin is about 260°C and the melting point of the solder is 220°C or lower is assumed. Examples of such thermoplastic resins include, for example, PPS, PPA, PBT, PA, etc. Examples of such solders include, for example, Sn-Cu-Ag based solder, etc.

[0063] The coating only needs to be able to make the heat conduction from the thermoplastic resin to the solder smaller than in the state where no coating exists. The composition of the coating having such characteristics is not limited, but in order to facilitate the coating of the solder, it is preferably contained a resin for coating. The material of the resin for coating is not limited, and in addition to the above-described UV curable resin, it may be composed of various resins, for example, thermoplastic resins, etc.

[0064] The coating only needs to be able to make the heat conduction from the thermoplastic resin to the solder smaller than in the state where no coating exists, and the materials and compositions therefor may be in various forms. For example, the configuration is not limited to that of the above-described embodiment where particles having a lower thermal conductivity than the resin for coating are contained in the resin for coating, and the resin for coating may be composed of a resin having a lower thermal conductivity than the thermoplastic resin.

[0065] Particles having a lower thermal conductivity than the resin for coating only need to be able to suppress heat conduction from the thermoplastic resin to the solder compared to the state where only the resin for coating is present, and may be realized by various particles. For example, hollow particles and the like can be mentioned.

Explanation of Signs

[0066] 1... Electronic component, 10... Substrate, 11... Hole element, 12... Terminal, 12a... End portion, 13... Solder, 14... Coating, 15... Spacer, 15a... Buffer portion, 20... Coated portion, 21... Window portion, 21a... Surface, 22... Connector connection portion, 22a... Space, 100... Substrate, 110... Stator core, 112... Insulator, 114... Coil, 120... Terminal, 150... Spacer, 200... Coated portion

Claims

1. A substrate with components joined by solder, A coating that covers the solder, A covering part made of a thermoplastic resin that covers the substrate and the coating and has a melting point higher than that of the solder, An electronic component comprising the above.

2. The coating, Contains a resin for coating and particles with a lower thermal conductivity than the resin for coating, The electronic component according to Claim 1.

3. There are a plurality of the solders on the substrate, The coating covers all the solders except the solder isolated from the thermoplastic resin, The electronic component according to Claim 1 or Claim 2.

4. The component includes a terminal electrically connected to an external device and a sensor element, The thermoplastic resin exposes a part of the terminal and covers the substrate and the coating including the sensor element, The electronic component according to Claim 1 or Claim 2.

5. The component includes a terminal electrically connected to an external device and a circuit component for controlling a motor, The thermoplastic resin exposes a part of the terminal and covers the substrate and the coating including the circuit component and the stator core of the motor, The electronic component according to Claim 1 or Claim 2.

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