Control circuit unit

Abstract

This invention provides a control circuit unit that can reduce manufacturing costs by saving on the amount of sealing resin used. [Solution] The device comprises a case 3 and a substrate 2 on which a contact 5a is provided that makes electrical contact with the contacts of the mating connector 7 when connected to the mating connector 7, and electronic components 6a and 6b are mounted, and which is placed in a substrate housing chamber 9 provided in the case 3 and sealed with a sealing resin. On the inner surface of the substrate housing chamber 9, protrusions 15a and 15b are integrally formed at positions that avoid the electronic components 6a and 6b on the substrate 2.

Description

Technical Field

[0001] The present invention relates to a control circuit unit.

Background Art

[0002] For example, Patent Document 1 discloses a control circuit unit that is connected to a mating connector provided in a vehicle and controls various devices mounted on the vehicle. The control circuit unit includes a substrate on which electronic components are mounted and housed in a case, and realizes the control functions of various devices by conducting the contacts of the substrate to the contacts of the mating connector when connected to the mating connector.

[0003] The substrate on which the electronic components are mounted needs to be protected from moisture and vibration, and at the same time, the heat generated by the electronic components needs to be released outside the case. Therefore, after inserting and arranging the substrate from the opening of the case, a measure is taken to inject a liquid sealing resin from the opening and cure it to seal the substrate in the case, thereby realizing a waterproof function, a vibration-proof function, and a heat dissipation function for the substrate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, the sealing resin is required to have water resistance and appropriate elasticity for protecting the substrate, and also has characteristics that do not thermally degrade the electronic components during injection and curing into the case, such as low melting point or room temperature curing. In view of this point, urethane resin (PU) or the like is used as the sealing resin, but this type of resin material is relatively expensive. Therefore, in order to reduce costs, it is desired to reduce the amount of the sealing resin used.

[0006] This invention was made to solve these problems, and its objective is to provide a control circuit unit that can reduce the amount of sealing resin used and thereby reduce manufacturing costs. [Means for solving the problem]

[0007] To achieve the above objective, the control circuit unit of the present invention comprises a case and a substrate on which contacts are provided that make electrical contact with the contacts of the mating connector when connected to the mating connector, and on which electronic components are mounted, and which is placed in a substrate housing chamber provided in the case and sealed with a sealing resin, and a projection is integrally formed on the inner surface of the substrate housing chamber at a position that avoids the electronic components on the substrate.

[0008] In other embodiments, the substrate may be inserted into the substrate housing chamber through an opening formed in the substrate housing chamber and placed in the substrate housing chamber, and the protrusions may be formed as a plurality of ribs that extend along the insertion direction of the substrate and are arranged in parallel in the width direction of the substrate perpendicular to the insertion direction.

[0009] In other embodiments, the ribs may be spaced apart from the substrate and the electronic components, and a sealing resin may be interposed between the protrusions and the substrate and the electronic components.

[0010] In other embodiments, electronic components may be mounted on both sides of the substrate, and ribs may be provided corresponding to both sides of the substrate.

[0011] In another embodiment, the ribs may gradually decrease in height towards the opening of the substrate housing chamber. [Effects of the Invention]

[0012] According to the control circuit unit of the present invention, it is possible to reduce the amount of sealing resin used and thereby reduce manufacturing costs. [Brief explanation of the drawing]

[0013] [Figure 1]It is a perspective view showing the control circuit unit and the counterpart connector of the embodiment. [Figure 2] It is an exploded perspective view showing a control circuit unit with the sealing resin not shown. [Figure 3] It is a view taken in the direction of arrow A in FIG. 2. [Figure 4] It is a sectional view taken along line IV-IV in FIG. 3. [Figure 5] It is a sectional view taken along line V-V in FIG. 3. [Figure 6] It is a sectional view taken along line VI-VI in FIG. 3. [Figure 7] It is a sectional view taken along line VII-VII in FIG. 3. [Figure 8] It is a perspective view showing a case and an injection mold with the mold opened. [Figure 9] It is a sectional view corresponding to line IX-IX in FIG. 8. [Figure 10] It is a view taken in the direction of arrow corresponding to FIG. 3 showing another example with different arrangement of electronic components. [Figure 11] It is a sectional view taken along line XI-XI in FIG. 10. [Figure 12] It is a view taken in the direction of arrow corresponding to FIG. 3 showing another example in which the ribs on the lower side of the substrate body are omitted. [Figure 13] It is a sectional view corresponding to FIG. 5 showing another example in which the height of the ribs is gradually reduced.

Mode for Carrying Out the Invention

[0014] Hereinafter, an embodiment of a control circuit unit embodying the present invention will be described. FIG. 1 is a perspective view showing the control circuit unit and the counterpart connector of the present embodiment, and FIG. 2 is an exploded perspective view showing the control circuit unit with the sealing resin not shown.

[0015] The control circuit unit 1 has a substrate 2 and a case 3 made of synthetic resin. The substrate 2 consists of a substrate body 4 and a card edge connector 5 provided on one side edge of the substrate body 4, and a plurality of electronic components 6 are mounted on the substrate body 4. The electronic components 6 are connected to each other via conductor patterns (not shown) on the substrate body 4, whereby the electric circuit formed on the substrate body 4 is electrically connected to the card edge connector 5.

[0016] The control circuit unit 1 is configured by arranging such a substrate 2 in the case 3. Although details will be described later, when a mating connector 7 is connected to a connector fitting portion 10 provided on one side of the case 3, the control circuit unit 1 is connected to an electric device to be connected via the card edge connector 5 and the mating connector 7.

[0017] The control circuit unit 1 of the present embodiment functions as an ECU (engine control unit) for controlling the engine of a motorcycle. The vehicle is equipped with a fuel injection valve, an ignition device, or various sensors of the engine, etc., and these electric devices are connected to the control circuit unit 1 via the mating connector 7, and the fuel injection and ignition timing of the engine are controlled by the control circuit unit 1.

[0018] In the following description, following the posture shown in FIG. 1, the upper surface of the substrate body 4 is referred to as the upper surface, the lower surface is referred to as the lower surface, and the direction orthogonal to the upper and lower surfaces of the substrate body 4 is referred to as the vertical direction. Further, the direction in which the substrate 2 is inserted into and removed from the case 3 is referred to as the substrate insertion / removal direction, and the direction orthogonal to the vertical direction and the substrate insertion / removal direction is referred to as the substrate width direction.

[0019] FIG. 3 is a view taken in the direction of arrow A in FIG. 2, FIG. 4 is a sectional view taken along line IV-IV in FIG. 3, FIG. 5 is a sectional view taken along line V-V in FIG. 3, FIG. 6 is a sectional view taken along line VI-VI in FIG. 3, and FIG. 7 is a sectional view taken along line VII-VII in FIG. 3. The circuit board body 4 is a roughly square plate, with electronic components 6 mounted on both its upper and lower surfaces. In the following description, the electronic components on the upper surface of the circuit board body 4 will be designated 6a, and those on the lower surface will be designated 6b to distinguish them. On the upper surface of the circuit board body 4, several relatively large electronic components 6a are concentrated in the approximate center in the width direction of the circuit board, and one electronic component 6a is also placed at the edge in the width direction of the circuit board. In contrast, on the lower surface of the circuit board body 4, one electronic component 6b is placed in the approximate center in both the insertion / removal direction and the width direction of the circuit board.

[0020] In the card edge connector 5, multiple contacts 5a are formed on one side edge of the main board 4 by a conductive pattern. Specifically, each contact 5a is arranged in a row along one side edge on both the upper and lower surfaces of the main board 4 in the width direction of the board, and these contacts 5a are electrically connected to the electrical circuits on the main board 4.

[0021] Overall, case 3 is a cylindrical shape that is flattened vertically and extends in the direction of inserting and removing the circuit board, with its upper surface bulging upwards to prevent interference with the electronic component 6a. A partition wall 8 is formed inside case 3, and this partition wall 8 divides the inside of case 3 into a circuit board housing chamber 9 and a connector mating section 10. The circuit board housing chamber 9 opens toward the side into which the circuit board 2 is inserted (opposite the mating connector 7), and the circuit board 2 is inserted through this opening 9a. Specifically, guide grooves 11 are formed on both sides in the circuit board width direction inside the circuit board housing chamber 9, and the circuit board 2 is inserted into the circuit board housing chamber 9 and positioned in a predetermined location while being guided by these guide grooves 11.

[0022] In this state, the card edge connector 5 protrudes into the connector mating portion 10 through a slit 8a formed in the partition wall 8. As shown in Figures 4 and 5, a sealing groove 8b is formed around the slit 8a, and the sealing resin 12 injected into this sealing groove 8b and hardened seals the gap between the substrate 2 and the inner circumference of the slit 8a.

[0023] The connector mating portion 10 opens toward the mating connector 7, and when the mating connector 7 is connected to the connector mating portion 10, the mating connector 7 is inserted into the connector mating portion 10 through the opening 10a, thereby connecting the control circuit unit 1 and the mating connector 7. The configuration of this connection point is not directly related to the gist of the present invention, so a detailed explanation is omitted, but in the connected state, each contact 5a of the card edge connector 5 is electrically connected to each contact of the mating connector 7, and a seal (not shown) prevents rainwater and the like from entering the connection point.

[0024] A sealing resin 13 is injected into the substrate housing chamber 9 of case 3 and cured. This sealing resin 13 seals the substrate 2, protecting it from moisture and vibration, while allowing the heat generated by the electronic components 6a and 6b to escape to the outside of case 3 via the sealing resin 13. The procedure for injecting the sealing resin 13 is well known, as described in, for example, Patent Document 1, so only a brief outline will be given. First, the substrate 2 is inserted and positioned in the substrate housing chamber 9, and case 3 is held in a position with its connector mating portion 10 facing upwards and open. Next, the sealing resin 12 is injected into the sealing groove 8b through the opening 10a, and after curing, the sealing resin 12 closes the gap between the substrate 2 and the inner circumference of the slit 8a. After inverting the position of case 3 upside down, the sealing resin 13 is injected into the substrate housing chamber 9 through the opening 9a and cured, sealing the substrate 2 within the substrate housing chamber 9 with the sealing resin 13.

[0025] As previously mentioned, relatively expensive urethane resins are used as the sealing resin 13, and there has been a long-standing demand to reduce the amount used in order to lower costs. In light of this demand, the present invention focuses on the price difference between the sealing resin 13 and the resin material applied to the molding of the case 3, and features a large number of ribs 15 integrally formed on the inner surface of the substrate housing chamber 9 of the case 3, which will be described in detail below. The ribs 15 correspond to the "projections" of the present invention.

[0026] Each rib 15 extends in the board insertion / removal direction and is arranged side by side in the board width direction, at a position that avoids interference with the electronic components 6a and 6b on the board body 4. As a result, the ribs 15 are widely distributed within the board housing chamber 9. In the following description, the ribs on the upper side of the board body 4 will be designated 15a, and the ribs on the lower side will be designated 15b to distinguish them.

[0027] As shown in Figures 3-6, on the upper side of the substrate body 4, four ribs 15a and two ribs 15a are integrally formed on the upper inner surface of the substrate housing chamber 9 on both sides of the electronic component 6a, which is positioned approximately in the center in the width direction of the substrate. Each rib 15a has a square cross-section and is arranged side by side at equal intervals in the width direction of the substrate (indicated as interval A in Figure 3). In the direction of inserting and removing the substrate, it extends linearly from the partition wall 8 toward the opening 9a of the substrate housing chamber 9 while maintaining the same cross-section at a predetermined height (indicated as height B in Figure 3), and its height gradually decreases in a tapered manner near the opening 9a.

[0028] The tip (lower end) of each rib 15a is spaced apart from the upper surface of the substrate body 4 (shown as gap C in Figure 3), and the side of the rib 15a closest to the electronic component 6a is also spaced apart from the electronic component 6a (shown as gap D in Figure 3). As a result, the cured sealing resin 13 is interposed between each rib 15a and the upper surface of the substrate body 4 and the electronic component 6a, and water resistance, vibration resistance, and heat dissipation functions are obtained without any problems.

[0029] Furthermore, as shown in Figures 3-5 and 7, on the lower side of the substrate body 4, six ribs 15b and four ribs 15b are integrally formed on the lower inner surface of the substrate housing chamber 9 on both sides of the electronic component 6b, which is positioned approximately in the center in the width direction of the substrate. Each rib 15b has a rectangular cross-section and is arranged in parallel at equal intervals (indicated as interval A in Figure 3) in the width direction of the substrate. In the direction of inserting and removing the substrate, it extends linearly from the partition wall 8 toward the opening 9a of the substrate housing chamber 9 while maintaining the same cross-section at a predetermined height (indicated as height B in Figure 3), and its height gradually decreases in a tapered manner near the opening 9a.

[0030] The tip (upper end) of each rib 15b is spaced apart from the lower surface of the substrate body 4 (shown as gap C in Figure 3), and the side of the rib 15b closest to the electronic component 6b is also spaced apart from the electronic component 6b (shown as gap D in Figure 3). As a result, the cured sealing resin 13 is interposed between each rib 15b and the lower surface of the substrate body 4 and the electronic component 6b, and water resistance, vibration resistance, and heat dissipation functions are obtained without any problems.

[0031] Each rib 15a and 15b is formed by the core of the mold when the case 3 is injection molded. Figure 8 is a perspective view showing the case and the injection molding die with the mold opened, and Figure 9 is a cross-sectional view corresponding to the line IX-IX in Figure 8. The mold 16 consists of an upper mold 17, a lower mold 18, a front mold 19, and a rear mold 20. When the mold 16 is closed, a cavity corresponding to the shape of the case 3 is formed inside, and molten resin is injected into this cavity to form the case 3. At this time, the upper surface of the case 3 is mainly formed by the upper mold 17, the lower surface of the case 3 is formed by the lower mold 18, the interior of the substrate housing chamber 9 is formed by the core 19a of the front mold 19, and the interior of the connector mating portion 10 is formed by the core 20a of the rear mold 20. The core 19a of the front mold 19 has grooves 19a1 formed in it that correspond to the shapes of the ribs 15a and 15b, so that the molten resin that enters into each groove 19a1 integrally forms the ribs 15a and 15b on the inner surface of the substrate housing chamber 9. When the mold is opened, the core 19a of the front mold 19 is pulled out along the extending direction of the ribs 15a and 15b, so that the mold can be opened without being obstructed by the ribs 15a and 15b.

[0032] For injection molding of Case 3, thermoplastic resins, such as polybutylene terephthalate resin (PBT), are used. This type of resin is less expensive than urethane resin used in the sealing resin 13. Therefore, compared to a typical control circuit unit that does not form ribs 15a and 15b, although the total amount of polybutylene terephthalate resin and urethane resin forming Case 3 is the same, the volume of expensive urethane resin is replaced by inexpensive polybutylene terephthalate resin by the volume of ribs 15a and 15b. As a result, the amount of expensive sealing resin 13 used can be reduced, thereby lowering the manufacturing cost of the control circuit unit 1.

[0033] In particular, in this embodiment, since the ribs 15a and 15b are widely arranged within the substrate housing chamber 9 based on the arrangement of each electronic component 6a and 6b, a large number of ribs 15a and 15b can be formed within the substrate housing chamber 9. As a result, more urethane resin can be replaced with polybutylene terephthalate resin, thereby achieving further cost reduction.

[0034] In addition, this embodiment employs multiple ribs 15a and 15b that extend in the substrate insertion / removal direction as protrusions and are arranged in parallel in the substrate width direction. The integral formation of these ribs 15a and 15b improves the strength and rigidity of the case 3. Therefore, even if, for example, a flying stone or the like collides with the control circuit unit 1 while the vehicle is in motion, damage to the case 3 can be prevented. Furthermore, warping of the case 3 can be prevented, reducing the load on the internal substrate 2, and vibration resistance can be improved to strengthen the protection of the substrate 2. These factors improve the durability and, consequently, the reliability of the control circuit unit 1.

[0035] Incidentally, when manufacturing multiple types of control circuit units 1 with different control functions, different types of electronic components 6a, 6b, or electronic components 6a, 6b in different arrangements, will be mounted on the main board 4 of each control circuit unit 1. In this case as well, this embodiment can be handled at low cost, and the details will be described below as a separate example.

[0036] [Another example] Figure 10 is a view corresponding to the arrow in Figure 3, which shows an alternative example, and Figure 11 is a cross-sectional view taken along line XI-XI in Figure 10. In contrast to the control circuit unit 1 of the embodiment shown in Figures 3 and 7, the control circuit unit 1 of this alternative example 1 has one additional electronic component 6b1 on the lower surface of the main board body 4. Since the added electronic component 6b1 is positioned offset in the width direction of the board relative to the original electronic component 6b (on the left side in Figure 11), the number of ribs 15b on that side is reduced from six to four to prevent interference with the added electronic component 6b1.

[0037] Therefore, in this alternative example 1 as well, while ensuring water resistance, vibration resistance, and heat dissipation functions with the sealing resin 13, the expensive urethane resin can be replaced with inexpensive polybutylene terephthalate resin by the volume of the ribs 15a and 15b, thereby reducing the manufacturing cost of the control circuit unit 1.

[0038] In addition, if alternative example 1 is implemented instead of the embodiment, it can be done simply by replacing the front mold 19, which is involved in the molding of the ribs 15a and 15b, among the molds 16 shown in Figure 8. Specifically, it can be done by simply preparing a new front mold 19 having a core 19a with grooves 19a1 formed according to the arrangement of the ribs 15a and 15b shown in Figure 11, and the upper mold 17, lower mold 18, and rear mold 20 can be reused from the embodiment. Therefore, this factor also contributes to reducing the manufacturing cost of the control circuit unit 1.

[0039] The number of ribs 15a and 15b can be arbitrarily increased or decreased in accordance with the addition or reduction of electronic components 6a and 6b on the substrate body 4. For example, if an electronic component 6b is added to the left end of Figure 11, or if an electronic component 6b is added to the right end of Figure 11, the ribs 15b that interfere with the added electronic component 6b should be eliminated. Conversely, if all electronic components 6b on the underside of the substrate body 4 are eliminated, the ribs 15b should be arranged in parallel at arbitrary intervals in the width direction of the substrate.

[0040] The embodiments of the present invention are not limited to these embodiments. For example, in the above embodiments and other examples, the invention is embodied in a control circuit unit 1 that functions as an ECU for engine control of a motorcycle, but the present invention is not limited thereto and may be modified for various applications.

[0041] Furthermore, in the above embodiment and other examples, ribs 15a and 15b are provided on both the upper and lower surfaces of the substrate body 4, respectively, but this is not the only option. For example, as shown in Figure 12, the lower rib 15b of the substrate body 4 may be omitted.

[0042] Furthermore, in the above embodiment and other examples, each rib 15a, 15b is extended from the partition wall 8 toward the opening 9a of the substrate housing chamber 9 while maintaining the same cross-section, but this is not the only option. For example, as shown in Figure 13, the height of each rib 15a, 15b may be gradually reduced toward the opening 9a of the substrate housing chamber 9 from the partition wall 8. This functions as a draft angle, which has the effect of making it easier to demold during injection molding. [Explanation of Symbols]

[0043] 1 Control circuit unit 2 circuit boards 3 cases 5a contact 6a,6b Electronic parts 7. The other side connector 9. Circuit board housing room 9a opening 13 Sealing resin 15a, 15b Ribs (projections)

Claims

1. The case and, The case comprises a circuit board on which electronic components are mounted and which is placed in a circuit board housing chamber provided in the case and sealed with a sealing resin, and which has contacts that make electrical contact with the contacts of the mating connector when connected to the mating connector, On the inner surface of the substrate housing chamber, a projection is integrally formed at a position that avoids the electronic components on the substrate. A control circuit unit characterized by the following features.

2. The substrate is inserted through an opening formed in the substrate housing chamber and placed inside the substrate housing chamber. The aforementioned protrusions are formed as a plurality of ribs that extend along the insertion direction of the substrate and are arranged side by side in the width direction of the substrate perpendicular to the insertion direction. The control circuit unit according to claim 1, characterized by the present invention.

3. The ribs are spaced apart from the substrate and the electronic components, and the sealing resin is interposed between the protrusions and the substrate and the electronic components. The control circuit unit according to claim 2, characterized by the features described above.

4. The aforementioned electronic components are mounted on both sides of the substrate, The ribs are provided corresponding to both sides of the substrate. The control circuit unit according to claim 2, characterized by the features described above.

5. The ribs are arranged so that their height gradually decreases toward the opening of the substrate housing chamber. The control circuit unit according to claim 2, characterized by the features described above.

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