Connector structure

Abstract

To provide a connector structure that can improve the sealing performance of the fixed end of a connecting terminal and ensure good electrical conductivity with a mating connector at the tip.SOLUTION: A connector structure includes first to third connector terminals 25 to 27 molded and fixed inside first to third connector fitting portions 22 to 24 that are fitted with the mating connector, the one ends 25a to 27a of which are exposed to the opening side of a connector fitting portion, and a potting agent 35 that is filled into the inside through the opening of the connector mating portion and adhered to the outer surface of the exposed fixed end of each connector terminal, where silver plating 33 is applied to the outer surface of the tip of the first connector terminal, and tin plating 34, which is a material that easily binds to the hydroxyl group of the potting agent, is applied to the outer surface of the fixed end of the first to third connector terminals.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a connector structure of an electronic control unit mounted on a vehicle such as an electric power steering device.

Background Art

[0002] In a vehicle, a plurality of connectors are attached to connect the mounted devices to each other. As a conventional connector structure, the one described in the following Patent Document 1 previously filed by the applicant of the present application is known.

[0003] This conventional connector structure has a connector fitting portion that fits with a mating connector. This connector fitting portion has a rectangular tube-shaped housing made of synthetic resin that constitutes an outer wall, and connection terminals that are molded and fixed inside the housing. The housing has an opening at one axial end and a rectangular columnar recess formed inside. The connection terminals are connected to devices via a mating connector, and the fixed-side end portions are covered with a potting agent filled on the bottom side of the recess of the housing. The potting agent exhibits a sealing function that suppresses the intrusion of liquids such as water that has entered from the opening of the housing into the device side.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, while the conventional connector structure described above ensures a seal between the fixed end of the connector terminal and the housing of the connector mating portion by filling it with a potting agent, it does not describe the surface treatment of the connector terminal, and in particular, it does not consider the surface treatment of the fixed end coated with the potting agent or the tip portion that is not coated with the potting agent. Therefore, there is a risk that the adhesive strength between the fixed end and the potting agent and the conductivity with the mating connector cannot be sufficiently ensured.

[0006] This invention was devised in view of the technical problems of the conventional connector structures described above, and aims to provide a connector structure that can improve the sealing performance of the fixed end of the connecting terminal while ensuring good electrical conductivity with the mating connector at the tip. [Means for solving the problem]

[0007] A preferred embodiment of the present invention is a connector structure connected to a circuit board, comprising: a connection terminal molded and fixed inside a connector mating portion that mates with a mating connector, with a portion of which is exposed on the opening side of the connector mating portion; and a curable liquid resin material filled inside the connector mating portion from the opening and adhered to the outer surface of the exposed fixed end of the connection terminal. A first surface treatment layer is formed on the outer surface of the tip portion of the aforementioned connection terminal to which the curable liquid resin material is not adhered. The curable liquid resin material contains a component having a hydroxyl group, The outer surface of the fixed end is subjected to a treatment to increase the surface roughness in advance, and a second surface treatment layer of a material that readily bonds with the hydroxyl groups of the curable liquid resin is applied. The first surface treatment layer and the second surface treatment layer are applied at positions with a certain distance between them, without overlapping. It is characterized by the following. [Effects of the Invention]

[0008] According to a preferred embodiment of the present invention, it is possible to improve the sealing performance of the fixed end of the connection terminal while ensuring good electrical conductivity with the mating connector at the tip. [Brief explanation of the drawing]

[0009] [Figure 1]This is a schematic diagram of an electric power steering system to which the connector structure according to the present invention is applied. [Figure 2] This is an exploded perspective view of an electronic control unit used in the first embodiment of the present invention. [Figure 3] This is a longitudinal cross-sectional view of the main part of the electronic control unit used in this embodiment, with the unit attached to the motor unit. [Figure 4] This is a longitudinal cross-sectional view of the connector housing used in this embodiment. [Figure 5] This is a longitudinal cross-sectional view of a connector housing used in a second embodiment of the present invention. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the connector structure according to the present invention applied to the electronic control unit of an electric power steering system will be described based on the drawings.

[0011] Figure 1 is a schematic diagram of an electric power steering system to which the connector structure according to the present invention is applied.

[0012] The electric power steering system comprises an input shaft 2 to which steering torque is input from the steering wheel 1, and a motor unit 3 housing an electric motor that provides assist torque to the steering torque. The motor unit 3 is driven by an electronic control unit 4 (ECU). The electric power steering system also comprises a reduction gear 5 that amplifies the rotational torque of the electric motor, a pinion gear 6 that transmits the rotational torque of the reduction gear 5 and transmits the steering torque and steering angle from the steering wheel 1, and a rack gear 9 that converts the steering torque of the pinion gear 6 into linear motion and transmits the steering force to the front wheels 8 via the tie rod 7.

[0013] The steering force from the steering wheel 1 is received by the input shaft 2, and the torsion of the torsion bar arranged between the input shaft 2 and the pinion gear 6 is detected by the torque sensor 10. The steering force and the steering timing are calculated by the electronic control unit 4, and the electric motor is controlled by the calculated current value to generate the necessary assist torque. The torque sensor 10 and the electronic control unit 4 are connected by a wire harness WH.

[0014] Figure 2 is an exploded perspective view of the electronic control unit provided in the first embodiment of the present invention, Figure 3 is a longitudinal sectional view of the main part of the state where the electronic control unit provided in this embodiment is attached to the motor unit, and Figure 4 is a longitudinal sectional view of the connector housing provided in this embodiment.

[0015] The motor unit 3 includes an electric motor which is a three-phase alternating current type brushless motor, a motor case 3b that houses the electric motor, a shaft 3a that is rotationally driven by the electric motor, a sensor magnet S that is attached to the base end portion of the shaft 3a and detects the rotation of the shaft 3a by a hall element 31 described later, and a first energization terminal (three-phase motor terminal) 3e that is connected to each of the three-phase terminals of the electric motor. The shaft 3a applies an assist torque to the steering torque via the reduction gear 5. An annular exterior portion 3d having a large outer diameter dimension is provided on the side of the motor case 3b toward the electronic control unit 4.

[0016] As shown in FIGS. 2 and 3, the electronic control unit 4 is arranged on the base end portion side of the shaft 3a of the electric motor of the motor unit 3.

[0017] The electronic control unit 4 includes a housing 11 fixed to the annular exterior portion 3d of the motor case 3b, a cover 12 joined to the housing 11, a drive circuit board 13 that is housed between the housing 11 and the cover 12 and drives the electric motor, a control circuit board 14 that controls the drive of the drive circuit board 13, and a connector housing 15 that supplies power from a power battery (not shown) to the drive circuit board 13, the control circuit board 14, and the electric motor.

[0018] The housing 11 is formed, for example, in a box shape with an open top made of an aluminum alloy material or the like, and has a bottom wall 11a and side walls 11b erected on the edges of the bottom wall 11a. A first opening 11c for attaching the connector housing 15 is formed in the upper part of the bottom wall 11a, and a hole 11d is provided in the outer peripheral part of the first opening 11c. Further, the housing 11 is formed with four female screw holes 11e for screwing fixing screws for fixing the connector housing 15 at the four corners of the outer peripheral part of the first opening 11c.

[0019] A cylindrical joint part 11f that fits into the opening of the exterior part 3d is formed in the lower part of the bottom wall 11a on the side of the motor case 3b, and four female screw holes 11g for fixing are formed at the four corners. The motor case 3b is fixed via the exterior part 3d by fixing screws screwed into the respective female screw holes 11g. The bottom wall 11a is formed with a circular second opening 16 that penetrates through the center position inside the joint part 11f and houses the sensor magnet S attached to the base end part of the shaft 3a. Below this second opening 16, three third openings 17 through which the first power supply terminals (three-phase motor terminals) 3e on the side of the electric motor are inserted are formed. Further, oblong fourth openings 19 through which the tip parts of a plurality of second power supply terminals 18 connecting the two circuit boards 13 and 14 face are formed diagonally upward to the left and right of the second opening 16.

[0020] Furthermore, as shown in FIG. 3, a plurality of cylindrical board fixing parts 20 for fixing the control circuit board 14 are provided on the side of the bottom wall 11a on the cover 12 side.

[0021] The cover 12 is formed, as shown in FIGS. 2 and 3, in a rectangular shape along the outer shape of the housing 11 using an aluminum alloy material or the like, and closes the opening of the housing 11. The cover 12 is integrally formed with a fitting protrusion 12a that fits into a fitting groove formed in the lower part of the side wall 11b of the housing 11 along the outer peripheral edge on the housing 11 side. Further, the cover 12 is formed with female screw holes 12b into which a plurality of screw parts for fixing the drive circuit board 13 are screwed at the left and right edges.

[0022] The connector housing 15 is integrally formed from a synthetic resin material and, as shown in Figures 2 to 4, comprises a substantially rectangular housing body 21 attached to the outer peripheral edge of the first opening 11c of the housing 11, a first connector fitting portion 22 positioned approximately in the center of the longitudinal direction of the housing body 21, a second connector fitting portion 23 positioned on one side of the first connector fitting portion 22, and a third connector fitting portion 24 positioned on the other side of the first connector fitting portion 22.

[0023] The housing body 21 integrally connects the first to third connector mating portions 22 to 24 and is fixed to the housing 11 by a plurality of fixing screws (not shown) while fitting over and closing the outer edge of the first opening 11c.

[0024] The first connector mating portion 22 is molded and fixed with synthetic resin material at approximately the center in the longitudinal direction of a pair of first connector terminals 25, which are power supply connection terminals on the connector side.

[0025] The second connector mating portion 23 molds and fixes the second connector terminals 26 (torque signal, ignition switch, etc.), which are connection terminals for various signals, to approximately the center of their longitudinal direction using a synthetic resin material.

[0026] The third connector mating portion 24 is formed by molding and fixing the approximately central part of the longitudinal direction of the third connector terminal 27 for CAN signals (communication) with a synthetic resin material.

[0027] The first to third connector mating portions 22 to 24 are each formed in a roughly rectangular tubular shape, with the internal insertion portions 22a, 23a, and 24a, into which the mating connector (not shown) is inserted, being formed in a rectangular prism shape, and each having an opening at one end in the axial direction that faces the insertion portions 22a to 24a. The cross-sectional area of ​​the first connector mating portion 22 is larger than that of the second and third connector mating portions 23 and 24.

[0028] The pair of first connector terminals 25 for power, the second connector terminal 26 for signals, and the third connector terminal 27 for communication are each formed from copper, which is a metallic material. The current and voltage carried through the first connector terminal 25 are higher than those carried through the second and third connector terminals 26 and 27. The first connector terminal 25 is formed in a strip shape, while the second and third connector terminals 26 and 27 are formed in a pin shape.

[0029] As shown in Figure 4, each connector terminal 25, 26, and 27 has one end 25a, 26a, and 27a positioned within the respective insertion parts 22a, 23a, and 24a of the connector mating parts 22, 23, and 24. On the other hand, the other ends 25b, 26b, and 27b of each connector terminal 25-27 extend through the housing body 21 towards the drive circuit board 13.

[0030] The pair of first connector terminals 25 are configured such that one end 25a of each terminal is electrically connected to the female terminal of a mating connector that is connected to a power battery. On the other hand, the other end 25b of each terminal is electrically connected to the second power supply terminal 28 of the drive circuit board 13, which will be described later, passing through the inside of the housing body 21. The second and third connector terminals 26 and 27 are configured such that one end 26a and 27a of each terminal is electrically connected to the female terminal of a mating connector (not shown), while the other ends 26b and 27b are connected to the signal and communication terminals of the control circuit board 14, which will be described later, via the drive circuit board 13.

[0031] The drive circuit board 13 relates to a power module that converts the current supplied from the connector housing 15 into three-phase (U-phase, V-phase, W-phase) alternating current and drives the electric motor in accordance with the control signal from the control circuit board 14.

[0032] The drive circuit board 13 is a plate-like structure made of a base metal material with an insulating layer in which a wiring pattern (not shown) is formed. It has a second power supply terminal 28 that is electrically connected to the other end 25b of the first connector terminal 25, a drive transistor (drive element, switching element) (not shown) where the upstream and downstream sides of each phase of the three-phase AC are electrically connected in series, and a third power supply terminal 29 for a three-phase electric motor that is electrically connected to one end of the first power supply terminal 3e.

[0033] The second power supply terminal 28 is positioned opposite the other end 25b of the first connector terminal 25, while each third power supply terminal 29 is positioned opposite one end of the first power supply terminal 3e. The first connector terminal 25 and the first to third power supply terminals 3e, 28, and 29 are electrically connected.

[0034] The control circuit board 14 is formed from a printed circuit board (glass epoxy substrate) or a ceramic substrate and includes a microphone computer (CPU) 30 that controls each drive transistor and a Hall element 31 that detects the rotation of the electric motor.

[0035] The CPU 30 and the Hall element 31 are electrically connected through a circuit pattern on the control circuit board 14, and this circuit pattern serves as the signal transmission path between the CPU 30 and the Hall element 31. In other words, the Hall element 31 uses the Hall effect to detect the magnetic field of the sensor magnet S and detect the rotation of the shaft 3a. This detection signal is input to the CPU 30 through the circuit pattern on the control circuit board 14.

[0036] The CPU 30 controls the drive transistor based on information input from the outside through the second and third connector terminals 24 and 26 of the connector housing 15, such as steering torque and vehicle speed signals, and detection signals from the Hall element 31.

[0037] As mentioned above, the first connector terminal 25 uses copper as its base material, and as shown in Figures 3 and 4, one end 25a exposed within the insertion portion 22a has a fixed end extending a predetermined length in the longitudinal direction from the bottom surface of the insertion portion 22a (the top surface of the housing body 21), and a tip extending from the fixed end toward the opening of the insertion portion 22a. As shown in Figures 3 and 4, the tip of the first connector terminal 25 is coated with a first surface treatment layer, silver plating 33 (shaded area), on its entire outer surface, while the fixed end is coated with a second surface treatment layer, tin plating 34 (shaded area), on its entire outer surface.

[0038] The silver plating 33 on the tip ensures good electrical conductivity with the female terminal of the mating connector, and gold plating can be used instead of silver plating 33. Furthermore, the silver plating 33 on the tip is applied only to the contact area with the female terminal of the mating connector. In other words, at the contact area between the metal of the tip and the female terminal of the mating connector, oxidation due to environmental conditions such as humidity and temperature may increase the electrical resistance and cause voltage changes over time. Therefore, by applying silver plating to the outer surface of the tip, oxidation is suppressed, the increase in electrical resistance is suppressed, and good electrical conductivity is ensured.

[0039] The tin plating 34 at the fixed end has good compatibility with the hydroxyl groups of the potting agent 35, which will be described later, and readily bonds with them, thus improving adhesion to the potting agent 35. In other words, the tin plating 34 readily bonds with the unpaired electrons of the nonmetallic atoms contained in the potting agent 35, resulting in good compatibility with the potting agent 35 and easy bonding with the surface of the tin plating 34, thus improving the adhesive strength between the two.

[0040] The tin plating 34 bonds more easily with the potting agent 35 than the silver plating 33 or the copper base material. Therefore, the adhesion to the potting agent 35 is greatest with the tin plating 34 compared to the silver plating 33 or the copper material.

[0041] Furthermore, the tin plating 34 at the fixed end has a vertical length in Figure 4 that is the same as the filling height within the insertion portion 22a of the potting agent 35, and is applied at a constant distance from the silver plating 33 without overlapping.

[0042] Furthermore, one end 26a and 27a of the second and third connector terminals 26 and 27 are exposed within the insertion portions 23a and 24a of the second and third connector mating portions 23 and 24, respectively. However, the tips of these one end 26a and 27a of the second and third connector terminals 26 and 27 are not silver-plated, and a predetermined area of ​​the outer surface of each fixed end is tin-plated 34 (shaded area).

[0043] Each of the insertion portions 22a, 23a, and 24a of the connector mating portions 22 to 24 is filled with a potting agent 35, which is a curable liquid resin material.

[0044] This potting agent 35 contains a component having a hydroxyl group, and as shown in Figure 4, it is filled from the bottom surface of each of the insertion parts 22a, 23a, and 24a to a predetermined length in the longitudinal direction of each fixed end of the first to third connector terminals 25, 26, and 27. In other words, as mentioned above, the outer surface of each fixed end is tin-plated 34, so each potting agent 35 is filled to at least the area where the tin plating 34 is applied. [Effects and benefits of the connector structure of this embodiment] According to the connector structure of this embodiment, since the surface treatment of silver plating 33 is applied only to the tip of the first connector terminal 25, good and stable electrical conductivity with the female terminal of the mating connector can be ensured.

[0045] In other words, as mentioned above, by applying the silver plating 33 surface treatment to the entire outer surface of the tip of the first connector terminal 25, oxidation can be suppressed and the increase in electrical resistance can be reduced, thereby ensuring stable and good electrical conductivity with the female terminal of the mating connector.

[0046] Furthermore, the fixed ends of the first to third connector terminals 25, 26, and 27 are not surface-treated with silver plating or other surface treatments. Instead, the copper base material is coated with tin plating 34, and the tin-plated areas are filled with potting agent 35, thus coating the terminals. This results in a chemical reaction between the tin plating 34 and the potting agent 35, which increases the bonding strength between them.

[0047] In other words, the chemical reaction between the tin plating 34 applied to the outer surface of each fixed end and the potting agent 35 having hydroxyl groups increases the bonding strength between them. As a result, the potting agent 35 improves the sealing performance between the outer surface of each fixed end and the molded portion of each fixed end.

[0048] Furthermore, since the effects of voltage drop are small for sensors and communication signals with relatively low current or voltage, costs can be reduced by not applying the expensive silver plating 33 to the tips of the second and third connector terminals 26 and 27. [Second Embodiment of the Present Invention] Figure 5 shows a second embodiment of the present invention, in which the first to third cylindrical portions 40, 41, and 42 are provided on the opposite side of the first to third connector mating portions 22 to 24 that sandwich the housing body 21 of the connector housing 15. Each of these cylindrical portions 40 to 42 is formed to have an outer shape that is substantially the same as that of the respective connector mating portions 22 to 24, and the amount of protrusion from the lower surface of the housing body 21 downward in the figure is set to be sufficiently shorter and substantially uniform than the amount of protrusion of each of the connector mating portions 22 to 24.

[0049] The first to third connector terminals 25, 26, and 27 extend linearly from each end 25a, 26a, and 27a without their other ends 25b, 26b, and 27b being bent, passing through the interior of each cylindrical portion 40 to 42 and extending downward.

[0050] The tip of one end 25a of the first connector terminal 25 has the same silver plating 33 surface treatment (shaded area) as in the first embodiment, but the outer surface of the fixed end is not tin-plated. Also, as in the first embodiment, the tips of one end 26a and 27a of the second and third connector terminals 26 and 27 are not silver-plated.

[0051] The first to third connector terminals 25, 26, and 27 have tin plating 34 applied to the outer surface of the fixed ends 25b, 26b, and 27b on the housing body 21 side, respectively.

[0052] Each of the cylindrical parts 40-42 is filled with potting agent 35. This potting agent 35 is applied to the bottom side of the housing body 21 of each cylindrical part 40-42, that is, the fixed end that has been tin-plated. department It is filled to completely cover the outer surface.

[0053] Therefore, in this second embodiment, as in the first embodiment, the tip of the first connector terminal 25 is subjected to the surface treatment of silver plating 33, thereby ensuring good and stable electrical conductivity with the female terminal of the mating connector.

[0054] Furthermore, the potting agent 35 is filled inside each cylindrical portion 40-42, and the chemical reaction between the potting agent 35 and the tin plating 34 on the outer surface of each fixed end increases the bonding strength between them. As a result, the potting agent 35 improves the sealing performance between the outer surface of each fixed end and the molded portion.

[0055] The present invention is not limited to the configuration of the above embodiment, and in addition to tin plating, other surface treatment layers that have good compatibility with the potting agent 35 containing hydroxyl groups, such as nickel plating performed as a base treatment, can also be applied.

[0056] Furthermore, since the copper material that forms the base material of each connector terminal 25, 26, and 27 is compatible with the potting agent 35, it is also possible to directly fill the exposed outer surface of the copper material with the potting agent 35.

[0057] Furthermore, it is possible to increase the surface roughness of each fixed end by pre-treating or shot peening the entire surface to enhance the bonding strength with the potting agent 35.

[0058] The connector structure described above can also be applied to electronic control devices and equipment other than the electric power steering system in this embodiment. [Explanation of Symbols]

[0059] 4...Electronic control unit, 11...Housing, 12...Cover, 13...Drive circuit board, 14...Control circuit board, 15...Connector housing, 21...Housing body, 22, 23, 24...First to third connector mating parts, 25, 26, 27...First to third connector terminals (connection terminals), 25a, 26a, 27a...One end, 25b, 26b, 27b...Other end, 33...Silver plating (first surface treatment layer), 34...Tin plating (second surface treatment layer), 35...Potting agent (curable liquid resin material), 40, 41, 42...Cylindrical part.

Claims

1. A connector structure connected to a circuit board, A connector terminal is molded and fixed inside the connector mating portion that mates with the other connector, with a portion of it exposed on the opening side of the connector mating portion. The connector mating portion is filled with a curable liquid resin material that is bonded to the outer surface of the exposed fixed end of the connecting terminal, A first surface treatment layer is formed on the outer surface of the tip portion of the connection terminal to which the curable liquid resin material is not adhered. The curable liquid resin material contains a component having a hydroxyl group, The outer surface of the fixed end is subjected to a treatment to increase the surface roughness in advance, and a second surface treatment layer of a material that readily bonds with the hydroxyl groups of the curable liquid resin is applied. A connector structure characterized in that the first surface treatment layer and the second surface treatment layer are applied at positions with a certain distance between them without overlapping.

2. The connector structure according to claim 1, The connector structure is characterized in that the second surface treatment layer is formed by tin plating that readily bonds with unpaired electrons of nonmetallic atoms contained in the posting agent, which is a curable liquid resin material.

3. The connector structure according to claim 1, A second connector mating portion is provided on at least one side of the connector mating portion and mates with the mating connector, A second connection terminal is molded and fixed to the second connector mating portion, with a portion of it exposed to the opening side of the second connector mating portion, and having a lower electrical current or voltage than the connection terminal, A curable liquid resin material is filled into the opening of the second connector mating portion and adhered to the outer surface of the exposed fixed end of the second connection terminal, A connector structure characterized by having the following features.

4. The connector structure according to claim 1, The connector structure is characterized in that the first surface treatment layer is gold-plated or silver-plated.

5. The connector structure according to claim 1, The connector structure is characterized in that the second surface treatment layer is tin-plated or nickel-plated.

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