Electronic component and manufacturing method

Abstract

The invention provides a technology capable of realizing miniaturization of an electronic component. An electronic component is provided with: a substrate to which a component is bonded by solder; a surface coating layer covering the solder; and a covering part which covers the substrate and the surface coating layer and is composed of a thermoplastic resin having a melting point higher than the melting point of the solder.

Description

Technical Field

[0001] The present invention relates to an electronic component and a manufacturing method thereof. Background Art

[0002] Conventionally, an electronic component controlled by a circuit component on a substrate has been known. For example, in Patent Document 1, a fluid pump controlled by a circuit component on a substrate is disclosed.

[0003] Patent Document 1: Japanese Patent No. 5704388

[0004] In the prior art, a motor housing including a motor and a driver unit including a substrate are connected, and the substrate is fixed to the base of the driver unit by screws. And, if the substrate is exposed without a cover, it is likely to cause a failure of the electronic component. Therefore, in most cases, the substrate is housed in a housing. Although the fixing by screws is a simple method, generally, a plurality of screws are required, and a portion for fixing the screws is also required on the substrate. In addition, a space corresponding to the length and width of the screws is required. Therefore, if screw fixing is adopted, it is difficult to miniaturize the electronic component. And, in order to adopt a structure in which the substrate is housed in a housing, it is necessary to design the housing so as to form a space including the substrate, and it is difficult to miniaturize the housing including the substrate. Summary of the Invention

[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 an electronic component.

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

[0007] That is, in the electronic component, the substrate to which components are joined by solder is covered with a thermoplastic resin. The thermoplastic resin has a melting point higher than that of the solder. Therefore, if the covering portion is formed by melting the thermoplastic resin in a state where the solder and the thermoplastic resin are in contact with each other, there is a possibility that the solder melts. However, since the solder is provided with a surface coating, heat conduction from the molten thermoplastic resin to the solder can be reduced, and the possibility of the solder melting again can be reduced.

[0008] According to this structure, the substrate can be covered without using screws to fix the substrate to the housing. Therefore, even if a structure for screw fixing is not provided on the substrate, the substrate can be protected by the covering portion. Therefore, compared with the case where a space for screw fixing is provided, the electronic component can be easily miniaturized. Brief Description of the Drawings

[0009] Figure 1Ais a top view showing an electronic component, Figure 1B is a left view showing an electronic component, Figure 1C is a front view showing an electronic component.

[0010] Figure 2A is a perspective view of the electronic component observed from an oblique side, Figure 2B is a perspective view of the substrate observed from an oblique side, Figure 2C is a perspective view of the substrate with a spacer mounted thereon observed from an oblique side.

[0011] Figure 3A is a top view showing the substrate, Figure 3B is a left view showing the substrate, Figure 3C is a front view showing the substrate.

[0012] Figure 4A is a top view showing the substrate with a spacer mounted thereon, Figure 4B is a left view showing the substrate with a spacer mounted thereon, Figure 4C is a front view showing the substrate with a spacer mounted thereon.

[0013] Figure 5 is a cross-sectional view showing an enlarged view of the joint portion of the terminal with respect to the substrate.

[0014] Figure 6 is a flowchart showing a manufacturing method of the electronic component.

[0015] Figure 7 is a flowchart showing a manufacturing method of the electronic component according to other embodiments.

[0016] Figures 8A to 8H is a view for explaining each process of the manufacturing method of the electronic component according to other embodiments.

[0017] Figures 9A to 9C is a view for explaining each process of the manufacturing method of the electronic component according to other embodiments.

[0018] Explanation of Reference Numerals

[0019] 1... Electronic component, 10... Substrate, 11... Hall element, 12... Terminal, 12a... End portion, 13... Solder, 14... Surface coating, 15... Spacer, 15a... Buffer portion, 20... Cover 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... Cover portion. Detailed Embodiments

[0020] Here, embodiments of the present invention will be described in the following order.

[0021] (1) Structure of the electronic component:

[0022] (2) Manufacturing method of the electronic component:

[0023] (3) Other embodiments:

[0024] (1) Structure of the electronic component:

[0025] Figure 1A is a top view showing the electronic component 1, Figure 1B is a left view showing the electronic component 1, Figure 1C is a front view showing the electronic component 1. Figure 2A is a perspective view of the electronic component 1 observed from an oblique side. In this specification, for the sake of convenience of explanation, as Figure 2A shown, the up, down, front, back, left, and right of the electronic component 1 are defined. In Figure 1A , the electronic component 1 is shown in a state where 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. In Figure 1B , the electronic component 1 is shown in a state where 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. In Figure 1C , the electronic component 1 is shown in a state where 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. In addition, in Figure 1C , it is shown in a state of passing through the substrate 10 provided inside the electronic component 1 and the structures around it.

[0026] 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 this embodiment, the electronic component 1 is a rotation sensor using a Hall element as a sensor element.

[0027] The shape of the covering portion 20 is not limited to the shape of the covering portion 20 in this embodiment. In this embodiment, since the electronic component 1 is a rotation sensor, the covering portion 20 is formed into a shape for enabling 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.

[0028] The window portion 21 is a cylindrical hole formed in the center of the upper surface of the covering portion 20 and extending in the up and down direction. The window portion 21 is open at the upper side, and there are a separator 15 and the covering portion 20 to be described later below, and it is not open. That is, one surface of the separator 15 is exposed below the window portion 21, and the covering portion 20 exists around the separator 15. The exposed surface of the separator 15 and the surface 21a of the covering portion 20 form the same surface perpendicular to the up and down direction.

[0029] In the present embodiment, a magnet is installed on a detection object that is an object to be detected for rotation by a rotation sensor. The electronic component 1 is fixed at a position above the window portion 21 of the magnet of the detection object and is used. A substrate 10 is disposed below the spacer 15, and a Hall element 11 (refer to Figure 1C ) is installed on the substrate 10. 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.

[0030] Terminals 12 described later are installed on the substrate 10. The Hall element 11 receives the supply of the driving 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 installed on the substrate 10 and extend in the front-rear direction.

[0031] The connector connection portion 22 is a cylindrical hole that protrudes forward in the covering portion 20. The front of the connector connection portion 22 is open, and the rear is closed by the covering portion 20. Among them, the front end portion 12a of the terminal 12 is disposed in the inner space 22a of the connector connection portion 22. The connector connection portion 22 is a portion for connecting a connector having a shape slightly smaller than the inner circumference of the inner space 22a. That is, by inserting a connector connected to an external device into the connector connection portion 22, the Hall element 11 on the substrate is electrically connected to the external device, and the rotation of the detection object can be detected by the external device.

[0032] Figures 3A to 3C It is a view showing the substrate 10 removed from the electronic component 1. Figure 3A It is a top view of the substrate 10, Figure 3B It is a left view of the substrate 10, Figure 3C It is a front view of the substrate 10. Figure 2B It is a perspective view of the substrate 10 observed from an oblique side. In this specification, for the sake of explanation, the up-down, front-rear, left-right of the electronic component 1 shown in Figure 2A are defined as the up-down, front-rear, left-right of the substrate 10. In Figure 3A , the substrate 10 is shown with the front-rear of the substrate 10 arranged on the right-left and the left-right arranged on the up-down. In Figure 3B , the substrate 10 is shown with the up-down of the substrate 10 arranged on the right-left and the left-right arranged on the up-down. In Figure 3C , the substrate 10 is shown with the up-down of the substrate 10 arranged on the up-down and the front-rear arranged on the right-left.

[0033] The substrate 10 is a cube, with the face perpendicular to the up-and-down direction being the largest. The substrate 10 is a printed circuit board on which printed wirings (not shown) are formed on this largest face. In the substrate 10, a part of the printed wiring is formed as pads, and the part other than the pads is covered with an insulator. The pads are the parts for electrically connecting components. In the present embodiment, components are mounted on the substrate 10 by solder.

[0034] In Figures 3A to 3C the substrate 10 shown, the components include a Hall element 11 and terminals 12. The Hall element is a chip having a plurality of terminals and is soldered at approximately the center of the mounting face of the substrate 10. In the present embodiment, there are six terminals 12 in total, and six terminals 12 are soldered along the front side edge in a manner arranged in the left-right direction at a position closer to the front in the substrate 10. In the present embodiment, the terminals 12 are in a thin plate shape, long in the front-back 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. In addition, the terminals 12 are bent approximately 90° at two positions in the long side direction, and the part near the end including the front end 12a of the terminals 12 is shorter in the left-right direction than other parts, but the whole of the terminals 12 forms an elongated shape extending in the front-back direction.

[0035] In the present embodiment, the covering part 20 is made of a thermoplastic resin, and when the covering part 20 is molded, the substrate 10 is also integrally molded. Therefore, when molding, a spacer 15 is used to position the substrate 10 in the mold of the covering part 20. Figures 4A to 4C is a diagram showing Figures 3A to 3C the state in which the spacer 15 is mounted on the substrate 10 shown. Figure 4A is a top view showing the substrate 10 on which the spacer 15 is mounted, Figure 4B is a left view showing the substrate 10 on which the spacer 15 is mounted, Figure 4C is a front view showing the substrate 10 on which the spacer 15 is mounted. Figure 2C is a perspective view showing the substrate 10 on which the spacer 15 is mounted as viewed obliquely from the side. Figures 4A to 4C The up-down, front-back, left-right of Figures 1A to 1C , Figures 3A to 3C is defined in the same way.

[0036] The spacer 15 is shaped like a hollow hexahedron with one face open, and the open face is mounted on the mounting face of the components on the substrate 10. In the present embodiment, the spacers 15 are mounted on each of the upper and lower mounting faces of the substrate 10. The Hall element 11 is housed inside one of the spacers 15. Corrugated buffer parts 15a are formed on the side faces of the spacer 15, that is, the front, back, left, and right faces in Figure 4A . With this structure, it is possible to prevent, for example, the substrate 10 from being damaged by the force acting when the mold contacts the spacer 15.

[0037] When the substrate 10 and the covering portion 20 are integrally formed, the spacer 15 is pre-mounted on the substrate 10. Therefore, the covering portion 20 and the Hall element 11 do not come into contact. In addition, the upper and lower surfaces of the spacer 15 are in contact with the plane of the mold used for forming. Therefore, the upper and lower surfaces of the spacer 15 can be exposed outside the covering portion 20. In Figure 1A 、 Figure 2A 、 the surface of the spacer 15 that is exposed and the surface 21a of the covering portion 20 are shown as viewed from above the window portion 21.

[0038] In the present embodiment, as described above, the covering portion 20 and the Hall element 11 do not come into contact. That is, when 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. By Figures 4A to 4C showing the state in which the substrate 10 enters a mold (not shown) for forming the covering portion 20, injecting a thermoplastic resin into the mold, and forming the covering portion 20, such a structure is achieved.

[0039] As Figure 1A 、 Figure 1C 、 Figure 2A and so on show, the substrate 10 is covered by the covering portion 20, and a part of the terminal 12 is exposed inside the connector connection portion 22, but the other part is covered by the covering portion 20. Therefore, the joint portion of 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), and the melting point is 224 °C and it is molded at 260 °C. On the other hand, the melting point of the solder joining the terminal 12 and the substrate 10 is 217 °C. Therefore, the thermoplastic resin constituting the covering portion 20 has a melting point higher than that of the solder.

[0040] Therefore, when the covering portion 20 is molded, if the thermoplastic resin comes into contact with the solder joining the terminal 12 and the substrate 10, there is a possibility that the solder will remelt. Therefore, in the present embodiment, the solder is applied in such a way that it does not come into direct contact with the thermoplastic resin. Figure 5 is a cross-sectional view showing an enlarged view of the joint portion of the terminal 12 and the substrate 10. In Figure 5 、 the state in which the terminal 12 on the substrate 10 is cut in a direction perpendicular to the left-right direction is shown. In addition, in Figure 5 、 the state after the covering portion 20 has been molded is shown, and the state in which the covering portion 20 is cut in the same cross-section as the terminal 12 is also shown.

[0041] ​In the portion where the terminal 12 is joined to the substrate 10, 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 surface coating 14 is formed in a range wider than the solder 13 around the solder 13. That is, the solder 13 formed on the terminal 12 is covered by the surface coating 14 so as not to contact the thermoplastic resin of the integrally formed covering portion 20. Therefore, it is possible to prevent the thermoplastic resin having a melting point higher than that of the solder 13 and being molded at a temperature higher than the melting point of the solder 13 from contacting the solder 13.

[0042] In the present embodiment, the surface coating 14 contains a resin for surface coating and particles having a thermal conductivity smaller than that of the resin for surface coating. That is, the surface coating 14 contains a plurality of particles, and the thermal conductivity of each particle is smaller than that of the resin for surface coating existing around each particle. Therefore, the surface coating 14 can reduce the possibility of heat conduction from the thermoplastic resin to the solder 13 and the solder 13 melting again.

[0043] In addition, in the present embodiment, the resin for surface coating is an ultraviolet curable resin. If an ultraviolet curable resin is used for the resin for surface coating, after the surface coating 14 covers the solder 13, the surface coating 14 can be cured by irradiating ultraviolet rays on the surface coating 14.

[0044] In addition, as long as the thermal conductivity of the particles contained in the surface coating 14 is smaller than that of the resin for surface coating, the possibility of heat conduction from the thermoplastic resin to the solder 13 and the solder 13 melting again can be reduced. Therefore, the particle structure, average particle diameter, mixing viscosity of the particles, etc. can be set to various values. For example, an example can be assumed in which the surface coating 14 contains particles having a hollow particle structure, an average particle diameter of 20 μm, and a mixing viscosity of the particles of 2700 mPa·s.

[0045] In addition, it is preferable that the layer thickness of the surface coating 14 is equal to or greater than the average particle diameter of the particles. According to this structure, in the thickness direction of the inner layer of the surface coating 14, a thickness that can accommodate one or more particles is achieved. Therefore, compared with the surface coating 14 having a thickness thinner than the average particle diameter of the particles, heat conduction of the particles can be more reliably suppressed. In addition, the layer thickness of the surface coating 14 is not limited. For example, when the average particle diameter of the particles is 40 μm, a structure with a layer thickness of 600 μm can be adopted. In addition, the average particle diameter of the particles can be selected, for example, from the range of 20 to 50 μm, and the layer thickness can be selected, for example, from the range of 100 μm to 1000 μm.

[0046] As Figure 3AAs shown in the figure, in the present embodiment, each of the plurality of terminals 12 is mounted on the substrate 10 by solder 13. Therefore, there are a plurality of solders 13 corresponding to each of the plurality of terminals 12, and the surface coating 14 covers the solder 13 of each of the plurality of terminals 12. Among them, 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 come into contact with the thermoplastic resin (i.e., is isolated), so the surface coating 14 may not be provided. That is, the surface coating 14 may not cover each of the solders isolated from the thermoplastic resin. According to this structure, compared with the structure in which the solder for mounting the Hall element 11 on the substrate 10 is used as the surface coating, the amount of material used for the surface coating 14 can be reduced.

[0047] (2) Method for manufacturing an electronic component:

[0048] Figure 6 It is a flowchart showing a method for manufacturing an electronic component. When manufacturing an electronic component, first, the component is mounted on the substrate (step S100). Specifically, a substrate 10 formed with a printed wiring for realizing a pre-designed circuit is prepared. In addition, each component for realizing the pre-designed circuit is mounted on the substrate 10 by solder. If it is the electronic component 1 as shown in the above Figure 1A , Figure 3A , Figure 4A etc., 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, Figures 3A to 3C the state shown.

[0049] Next, the surface coating resin and the particles are mixed (step S105). That is, a surface 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.

[0050] Next, the substrate is immersed in the coating agent (step S110). That is, the substrate is immersed in the coating agent prepared in step S105. At this time, if the surface coating 14 does not exist, the immersion is performed in such a manner that the solder located at the position in contact with the thermoplastic resin of the covering portion 20 is immersed in the coating agent.

[0051] Next, ultraviolet rays are irradiated (step S115). That is, after the substrate is taken out from the coating agent, ultraviolet rays are irradiated to the coating agent. If it is the electronic component 1 as shown in the above Figure 1A , Figure 3A , Figure 4A etc., ultraviolet rays are irradiated to the coating agent covering the solder 13 of the terminal 12. The state after the surface coating 14 is formed is, for example, Figures 4A to 4C the state shown.

[0052] Next, install the spacer (step S120). That is, in order to set the positions of the substrate within the covering portion and the substrate within the mold to predetermined positions, the spacer is installed on the substrate. In the case of the electronic component 1 shown in the above Figure 1A , Figure 3A , Figure 4A etc., the spacer 15 is installed on both sides of the substrate 10. The state after installing the spacer 15 is, for example, Figures 4A to 4C the state shown.

[0053] Next, perform integral molding (step S125). That is, the substrate with the spacer installed is placed in the mold, and the thermoplastic resin is injected into the mold. As a result, the thermoplastic resin is filled in the space around the substrate, and the substrate and the covering portion are integrally molded. In the case of the electronic component 1 shown in the above Figure 1A , Figure 3A , Figure 4A etc., the substrate 10 with the spacer 15 installed is placed in the mold for integral molding. The state after forming the covering portion 20 by integral molding is, for example, Figures 1A to 1C the state shown.

[0054] Through the above process, the substrate 10 and the surface coating 14 are covered by the covering portion 20, and the electronic component 1 with a part of the terminal 12 exposed is manufactured. According to the above structure, when performing integral molding, the possibility of remelting the solder 13 on the substrate 10 due to the heat from the molten thermoplastic resin can be reduced. With this structure, the substrate 10 can be covered without using screws to fix the substrate 10 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. Thus, the electronic component 1 can be miniaturized. In addition, in order to fix the substrate 10, screws are not necessarily required, so the number of components and the manufacturing man-hours can be reduced.

[0055] (3) Other embodiments:

[0056] The above embodiments are examples for implementing the present invention, and various other embodiments can be adopted in addition. For example, the electronic component only needs to include a substrate, a surface coating, and a covering portion, and the use of the electronic component is not limited. In addition, components other than the substrate can also be integrally molded with the substrate and formed with a covering portion.

[0057] Figure 7 ~FIG. 9 is a diagram showing an example of an electronic component in which an electric pump having a motor controlled by a substrate is an embodiment. Figure 7 is a flowchart showing a manufacturing method of the electronic component. Figures 8A to 8H , Figures 9A to 9C are diagrams for explaining each process.

[0058] In this embodiment, when manufacturing an electronic component, first, the components are mounted on a substrate (step S200). Specifically, a substrate 100 formed with a printed wiring for implementing a circuit for controlling a motor is prepared, and each circuit component for implementing the circuit is mounted on the substrate 10 by solder. Each circuit component is soldered, for example, by reflow. Figure 8A FIG. shows the substrate 100 after soldering.

[0059] Next, an insulator and a coil are mounted on a stator core (step S202). In this embodiment, a part of the substrate 100 and the components of the motor are integrally formed with a covering portion. Therefore, the components of the integrally formed motor are prepared. In this embodiment, the components of the integrally formed motor include a stator core, an insulator, and a coil.

[0060] In this embodiment, the motor includes a rotor and a stator core. The rotor is a component that rotates about a rotation axis. In this embodiment, the rotor is not an object to be integrally formed with the substrate 100. Further, here, the direction parallel to the rotation axis of the rotor is referred to as the axial direction, the direction perpendicular to the axial direction is referred to as the radial direction, and the rotation direction with respect to the rotation axis is referred to as the circumferential direction. In addition, the direction toward the rotation axis in the radial direction is referred to as the radially inner side, and the direction toward the direction opposite to the rotation axis in the radial direction is referred to as the radially outer side.

[0061] Figure 8C 、 Figure 8D FIG. shows the stator core 110 on which the insulator 112 and the coil 114 are mounted. Figure 8C FIG. shows a state of observing the stator core 110 along the radial direction, Figure 8D FIG. shows a state of observing the stator core 110 from an inclined direction. The stator core 110 is a component fixed to a motor housing or the like. Although the structure of the stator core 110 is not limited, in this embodiment, the stator core 110 is an annular component existing on the circumferentially outer side of the rotor. A plurality of stator teeth protruding radially inward are formed on the radially inner side of the annular stator core 110. In the circumferential direction, the space between the plurality of stator teeth is a slot, and a space for winding a coil is formed.

[0062] The insulator 112 is a component that sandwiches the stator teeth from both sides in the axial direction and is a component for insulating the stator core 110 and the coil 114. The coil 114 is wound around the stator teeth on which the insulator 112 is mounted and is wound radially outward of the insulator 112 and connected to the substrate 100. Further, a terminal or the like for winding a wiring extending from the coil 114 around the substrate 100 is provided on the insulator 112. In step S202, as described above Figure 8C 、 Figure 8D FIG. shows, the insulator 112 is mounted on the stator core 110 and the coil 114 is wound around it.

[0063] Next, the spacer 150 is installed (step S205). In the present embodiment, in order to set the position of the substrate 100 in the covering portion and the position of the substrate 100 in the mold to a predetermined position, and to set the position of the terminal joined to the substrate 100 to a predetermined position, the spacer 150 is installed on the stator core 110. Figure 8B An example of the spacer 150 is shown. The spacer 150 can be of any shape as long as it can set the positions of the substrate 100 and the terminal to predetermined positions.

[0064] In Figure 8E an example of installing the spacer 150 on the stator core 110 is shown. In addition, Figure 8F although the perspective view shown shows the terminal 120, the state of the spacer 150 is omitted. As Figure 8F shown, in the state where the substrate 100 does not exist, in a part of the terminal 120, there is no base for installing the terminal 120, etc., so the terminal 120 is positioned by installing it on the spacer 150. In addition, Figure 8E the terminal 120 shown in the upper right part of

[0065] is the same as the terminal 12 shown in FIG. 3, is a terminal for connecting a connector, and a part of it is covered by a covering portion 200 described later, and the remaining part is not covered by the covering portion 200 and is in an exposed state.

[0066] In Figure 8G an example of installing the substrate 100 on the spacer 150 is shown. As Figure 8G shown, the substrate 100 is positioned by the spacer 150. In addition, Figure 8H although the perspective view shown shows the substrate 100, the state of the spacer 150 is omitted.

[0067] Next, the substrate and the terminal are soldered (step S208). That is, in step S207, the end portion of the terminal 120 that protrudes from one surface of the substrate 100 is joined to the substrate 100 by solder.

[0068] Next, the surface coating resin and the particles are mixed (step S210). That is, a surface coating resin that is liquid at room temperature is prepared in a container, and a predetermined amount of particles is put into the container and mixed.

[0069] Next, the substrate is immersed in the coating agent (step S215). That is, the substrate is immersed in the coating agent prepared in step S210. Figure 9A This is a diagram for explaining the immersion. In step S210, solder on the substrate 100 is applied by moving the substrate 100 downward relative to the container V storing the coating agent C. Further, in the present embodiment, the immersion is performed in such a manner that all of the solder for bonding the components to the substrate 100 is immersed in the coating agent.

[0070] Next, ultraviolet rays are irradiated (step S220). That is, after the substrate 100 is taken out from the container V, ultraviolet rays are irradiated onto the coating agent.

[0071] Next, integral molding is performed (step S225). That is, the stator core 110 on which the spacer 150 and the substrate 100 are mounted is placed 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. Figure 9B , Figure 9C This is a diagram showing the covering portion 200 after integral molding. Figure 9B This shows a state of observing the covering portion 200 along the radial direction of the stator core 110 inside the covering portion 200. Figure 9C This shows a state of observing the covering portion 200 from an inclined direction. Through the above steps, an electronic component is manufactured in which the substrate 100 is covered with the covering portion 200, a surface coating of solder for mounting components on the substrate 100, the stator core 110, the insulator 112, the coil 114, and a part of the terminal 120, while the remaining part of the terminal 120 is exposed.

[0072] Even in the above structure, during integral molding, it is possible to reduce the possibility that the solder on the substrate 100 is remelted due to the heat from the molten thermoplastic resin. With this structure, the substrate 100 can be covered without using screws to fix the substrate 100 to the frame, and the electronic component can be miniaturized. In addition, since screws for fixing the substrate 10 are not required, the number of components and the manufacturing man-hours can be reduced.

[0073] The substrate only needs to be a substrate to which components are joined by soldering. That is, other electronic components joined to the substrate and circuits for transmitting and receiving various signals are formed on the substrate. The circuits formed on the substrate are not limited, and may be circuits for transmitting and receiving information between other electronic components, circuits for controlling other electronic components, or circuits controlled by other electronic components. The form of the components is not limited either, 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 soldering and may be various components. For example, they may be circuit components such as active components and passive components, integrated circuits, and terminals joined to other electronic components may also be components.

[0074] The surface coating only needs to cover the soldering. That is, the surface coating is a layer containing the soldering and only needs to exist between the soldering and the thermoplastic resin and prevent the soldering from directly contacting the thermoplastic resin. Moreover, as long as the existence of this surface coating can reduce the heat conduction from the molten thermoplastic resin to the soldering and the possibility of the soldering melting again.

[0075] In addition, the surface coating only needs to reduce the heat conduction from the thermoplastic resin to the soldering and the possibility of the soldering melting again. Therefore, in this regard, the material and thickness of the surface coating are not limited and can be realized in various states. And since the surface coating is a layer for preventing the thermoplastic resin from contacting the soldering, when there are components isolated from the thermoplastic resin on the substrate, the surface coating may not be provided in the soldering on such components.

[0076] The covering part only needs to be a part of the thermoplastic resin that covers the substrate and the above-mentioned surface coating and has a melting point higher than that of the above-mentioned soldering. That is, the thermoplastic resin only needs to cover the substrate. For example, it can be manufactured by integrally molding the substrate and the thermoplastic resin together.

[0077] In addition, the covering part only needs to cover the substrate and, together with the substrate, cover the surface coating on the components mounted on the substrate. The covering part only needs to cover all of the substrate and the surface coating on the components or cover them in such a way that no part is exposed to the outside. Components on the substrate that do not have a surface coating (for example, the terminals in the above-mentioned embodiment) may also be exposed to the outside of the covering part. Also, even for components on the substrate, parts without soldering may be exposed to the outside of the covering part.

[0078] A thermoplastic resin is a resin that melts into a liquid state when the temperature reaches or exceeds its melting point and becomes rubbery or glassy when the temperature is lower than the melting point. In addition, since the melting point of the thermoplastic resin is higher than that of the solder, if the thermoplastic resin comes into direct contact with the solder during molding, the solder may remelt. Although the melting point is not limited, for example, an example is assumed where the melting point of the thermoplastic resin is around 260°C and the melting point of the solder is 220°C or lower. Examples of such thermoplastic resins include PPS, PPA, PBT, PA, etc. Examples of such solders include Sn-Cu-Ag based solders, etc.

[0079] The surface coating only needs to reduce the heat conduction from the thermoplastic resin to the solder compared to the state without the surface coating. Although the composition of the surface coating having such characteristics is not limited, in order to facilitate the coverage of the solder, some include a resin for the surface coating. The material of the resin for the surface coating is not limited, and in addition to the above UV curable resin, it can also be composed of various resins, such as thermoplastic resins, etc.

[0080] The surface coating only needs to reduce the heat conduction from the thermoplastic resin to the solder compared to the state without the surface coating. Therefore, the material and composition can also be in various forms. For example, it is not limited to the structure where the resin for the surface coating contains particles with a lower thermal conductivity than the resin for the surface coating as in the above embodiment, and the resin for the surface coating can also be composed of a resin with a lower thermal conductivity than the thermoplastic resin.

[0081] Particles with a lower thermal conductivity than the resin for the surface coating only need to be able to inhibit the heat conduction from the thermoplastic resin to the solder compared to the state where only the resin for the surface coating exists, and various particles can be used to achieve this. For example, hollow particles, etc., can be cited.

Claims

1. An electronic component, characterized in that: have: a substrate to which components are joined by solder; a surface coating covering the solder; and The covering portion covers the substrate and the surface coating layer and is made of a thermoplastic resin having a melting point higher than that of the solder.

2. The electronic component according to claim 1, characterized in that The surface coating layer includes a surface coating resin and particles having a thermal conductivity lower than that of the surface coating resin.

3. The electronic component according to claim 1 or 2, characterized in that: There are a plurality of solders on the substrate. The surface coating covers all of the solder except for the solder isolated from the thermoplastic resin.

4. The electronic component according to claim 1 or 2, characterized in that: The above components include terminals electrically connected to external devices and sensor elements, The thermoplastic resin covers the substrate including the sensor element and the surface coating layer so that a part of the terminal is exposed.

5. The electronic component according to claim 1 or 2, characterized in that: The above components include terminals for electrical connection with external devices and circuit components for controlling the motor. The thermoplastic resin covers the substrate including the circuit component and the surface coating, and the stator core of the motor so that a part of the terminal is exposed.

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