Electronic control device and manufacturing method of the electronic control device

Abstract

To provide an electronic control device capable of improving resistance and reliability of a seal part, and a manufacturing method of the electronic control device.SOLUTION: In one embodiment of the present invention, an outer casing member covering an electron control part includes: a first outer casing member; and a second outer casing member. The first outer casing member includes an annular-shaped seal groove into which a liquid seal agent is filled. The second outer casing member includes an annular-shaped projection part housed in the seal groove. In a first side wall and a second side wall forming the seal groove, a top part of the second side wall is covered by the second outer casing member. When an interval between the first side wall and the annular-shaped projection part is a1, an interval between the second side wall and the annular-shaped projection part is a2, and an interval between the top part of the second side wall and the second outer casing member is b, the following equations of a1>b and a2>b are satisfied.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an electronic control device and a method for manufacturing an electronic control device. [Background technology]

[0002] The drive device of Patent Document 1 has a cover that forms a storage space for accommodating a control board together with an electric motor and a connector, and a first annular recess formed on a first end face of the electric motor and a first annular convex portion formed on a lower support surface of the connector are connected around the entire circumference of the first recess via a first adhesive, and further, a second annular recess formed on each of the upper support surface and the first connection surface of the connector and a second annular convex portion formed on the end face of the cover are connected around the entire circumference of the second recess via a second adhesive, thereby connecting the electric motor and the cover via the connector. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-188655 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in an electronic control device in which an electronic control unit is housed in an exterior member formed by assembling a first exterior member and a second exterior member, airtightness may be ensured by sealing the connection portion between the first exterior member and the second exterior member with a liquid sealing agent. However, if puddles form in the areas where the liquid sealant is exposed to the outside, and the interface between the liquid sealant and the exterior component is destroyed by salt corrosion or other factors, water could penetrate into the interior of the exterior component, potentially causing a short circuit or other problem.

[0005] The present invention has been made in consideration of the conventional situation, and its object is to provide an electronic control device and a manufacturing method for an electronic control device that can improve the resistance and reliability of the sealing portion. [Means for solving the problem]

[0006] Therefore, in one aspect of the electronic control device of the present invention, an exterior member covering an electronic control unit has a first exterior member and a second exterior member, the first exterior member has an annular seal groove filled with a liquid sealant, the second exterior member has an annular protrusion portion housed in the seal groove, and a top of the second side wall of a first side wall and a second side wall forming the seal groove is covered by the second exterior member, and when a1 is the distance between the first side wall and the annular protrusion portion, a2 is the distance between the second side wall and the annular protrusion portion, and b is the distance between the top of the second side wall and the second exterior member, a1>b and a2>b are satisfied.

[0007] In one embodiment of a manufacturing method for an electronic control device according to the present invention, an exterior member covering an electronic control unit has a first exterior member and a second exterior member, the first exterior member has an annular seal groove filled with liquid sealant, the second exterior member has an annular protrusion received in the seal groove, and an apex of the second side wall of a first side wall and a second side wall forming the seal groove is covered by the second exterior member, and the manufacturing method includes the steps of filling the seal groove with liquid sealant, and inserting the annular protrusion into the seal groove while narrowing the gap between the apex of the second side wall and the second exterior member to be smaller than the gap between the annular protrusion and an inner wall of the seal groove, thereby causing the liquid sealant to flow out of the seal groove from the gap between the first side wall and the annular protrusion to the outside of the seal groove. Effect of the Invention

[0008] According to the above invention, the durability and reliability of the sealing portion can be improved. [Brief description of the drawings]

[0009] [Figure 1]FIG. 2 is an exploded perspective view of an electric drive unit for an electric power steering device. [Diagram 2] FIG. [Diagram 3] FIG. 2 is an external perspective view of a motor cover of the electric drive device. [Figure 4] 5 is an enlarged cross-sectional view of a joint between a connector member and a motor cover. FIG. [Diagram 5] 11A to 11C are diagrams showing a process of assembling the motor cover to the connector member. [Figure 6] 11A and 11B are diagrams showing how a puddle occurs when the amount of liquid sealing agent spilling out to the outside is small. [Figure 7] 11A and 11B are diagrams for explaining setting of the height of a side wall that forms a seal groove. [Figure 8] 11 is a diagram for explaining the positioning of the apex of a side wall that forms a seal groove. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of the present invention will be described below. FIG. 1 is an exploded perspective view of an electric drive unit 101 of an electric power steering device for an automobile, which is an application example of an electronic control unit and a manufacturing method for an electronic control unit according to the present invention. FIG. 2 is a vertical cross-sectional view of the electric drive device 101 shown in FIG. FIG. 3 is a perspective view of the motor cover shown in FIG.

[0011] The electric drive unit 101 is an electric power steering device for an automobile that applies a steering assist force to a steering mechanism (not shown). The electric drive device 101 comprises a motor unit 1, an inverter power module 2, a circuit board 3 consisting of a multilayer circuit board bent into an approximately U-shape, a connector member 4 comprising a plurality of connectors assembled together, and a motor cover 5 attached to one end of the motor unit 1 so as to cover the inverter power module 2, the circuit board 3, and the connector member 4.

[0012] In the electric drive device 101, the inverter power module 2 and the circuit board 3 correspond to an electronic control unit, and a microcomputer, a power supply IC, a pre-driver circuit, and the like are mounted on the circuit board 3. In other words, the electric drive device 101 is a device that is made up of the motor unit 1 and an electronic control device.

[0013] The motor section 1 includes a motor accommodated inside a cylindrical housing 7 . A connecting portion 6a such as a gear or a spline is provided at the tip of the motor rotating shaft 6 protruding from the tip surface of the housing 7, and is connected to a steering mechanism (not shown) via this connecting portion 6a.

[0014] The motor of the motor unit 1 is, for example, a three-phase permanent magnet type brushless motor including a stator having a coil and a rotor having a permanent magnet. In this embodiment, the motor has two winding sets, and each winding set is driven and controlled by two electronic control units that are independent of each other.

[0015] One end of the housing 7 opposite the connecting portion 6a is configured as a bottom wall portion 7a having a horseshoe-shaped contour with part of the outer circumferential edge extending radially outward (radially from the motor shaft 6). A motor cover 5 having a horseshoe-shaped outline corresponding to the bottom wall portion 7a is attached so as to cover the bottom wall portion 7a. In the space defined between the bottom wall portion 7 a and the motor cover 5 , the inverter power module 2 , the circuit board 3 and the connector member 4 are housed one on top of the other in the axial direction of the motor rotating shaft 6 .

[0016] The inverter power module 2 includes two inverter modules 2A that drive the motor and a relay module 2B that serves as a neutral point relay for the coil, which are arranged to form an approximate U-shape surrounding the motor rotating shaft 6. The inverter module 2A and the relay module 2B are fixed to the end face of the motor section 1, that is, onto the bottom wall section 7a, via a pressing member 2C.

[0017] The connector member 4 includes three connectors 4 a , 4 b , and 4 c oriented in the same direction along the axial direction of the motor rotating shaft 6 . These connectors 4 a , 4 b , 4 c protrude to the outside through an opening 8 in the motor cover 5 .

[0018] The opening edge 5a of the motor cover 5 is fitted onto the outer periphery of the bottom wall portion 7a of the housing 7, and the gap between them is sealed by a liquid sealing agent 15 filled in a seal groove 14 on the outer periphery of the bottom wall portion 7a. The motor cover 5 is formed from a metal plate into a cup shape, and has a peripheral wall 5b and a bottom wall 5c that follow the outline of a horseshoe, with an opening 8 formed in the bottom wall 5c.

[0019] Moreover, crimped portions 16 are provided at a plurality of locations on the peripheral wall 5b of the motor cover 5 in the peripheral direction (direction along the circumferential direction centered on the motor rotating shaft 6). Then, after the motor cover 5 is fitted to the bottom wall portion 7a of the housing 7, the crimping portion 16 is crimped to the inner periphery side, whereby the motor cover 5 is fixed to the housing 7.

[0020] Further, the edge of the opening 8 provided in the bottom wall 5c of the motor cover 5 is bent at a substantially right angle toward the connector member 4 to form an annular protrusion 5d. On the other hand, a seal groove 4d is formed in the connector member 4 to accommodate the annular protrusion portion 5d, and the seal groove 4d is filled with liquid sealant 17, so that the joint between the connector member 4 and the motor cover 5 is sealed by the liquid sealant 17.

[0021] In other words, the seal groove 4d is a groove portion that opens toward the opposite side from the motor section 1 in the axial direction of the motor rotating shaft 6, and when the motor cover 5 is brought closer to the connector member 4 along the axial direction of the motor rotating shaft 6, the annular protrusion portion 5d of the motor cover 5 is inserted into the seal groove 4d, and the motor cover 5 is fixed to the housing 7 at a position where the annular protrusion portion 5d is stored in the seal groove 4d. The liquid sealing agents 15 and 17 are, for example, FIPG (Formed in Place Gasket) that retains elasticity even after hardening.

[0022] Here, the connector member 4 is a first exterior member part of which is exposed to the outside from the opening 8 of the motor cover 5, and has a seal groove 4d in which a liquid sealant 17 is filled. On the other hand, the motor cover 5 is a second exterior member having an annular protrusion 5d that is received in the seal groove 4d of the connector member 4. The inverter power module 2 and the circuit board 3 serving as an electronic control unit are covered with an exterior member constituted by the connector member 4 and the motor cover 5.

[0023] In the following, the structure of the joint between the connector member 4 and the motor cover 5, and the process of assembling the motor cover 5 to the connector member 4 will be described in detail. FIG. 4 is an enlarged cross-sectional view showing the seal groove 4d and the annular protrusion 5d housed in the seal groove 4d in a state where the connector member 4 is attached to the motor cover 5 (an enlarged view of the area surrounded by the dotted line in FIG. 2). FIG. 5 is a diagram showing a process of assembling the motor cover 5 to the connector member 4. As shown in FIG.

[0024] The annular seal groove 4d is defined by a first side wall 4d1 on the inner circumferential side, a second side wall 4d2 on the outer circumferential side, and a bottom wall 4d3. The top 4d2s of the second side wall 4d2 on the outer circumferential side is covered by the motor cover 5. In other words, the top 4d2s of the second side wall 4d2 is located within a sealed space covered by the motor cover 5. On the other hand, a top portion 4d1s of the first side wall 4d1 on the inner circumferential side is exposed to the outside.

[0025] Here, when the distance between the first side wall 4d1 and the annular protrusion 5d is a1, the distance between the second side wall 4d2 and the annular protrusion 5d is a2, and the distance between the top 4d2s of the second side wall 4d2 and the motor cover 5 is b, the shapes and dimensions of the sealing groove 4d and the annular protrusion 5d, as well as the mounting position of the motor cover 5, are set so as to satisfy a1>b and a2>b. When the distance between the tip end 5ds of the annular projection 5d and the bottom wall 4d3 (bottom surface) of the seal groove 4d is a3, it is more preferable that the relationships a1>b, a2>b, and a3>b are satisfied. The above dimensional settings are intended to control the flow of liquid sealant 17 during the process of assembling motor cover 5 to connector member 4, as described below, and to intentionally increase the amount of liquid sealant 17 flowing out to the outside.

[0026] When assembling the motor cover 5 to the connector member 4 in the manufacture of the electric drive device 101, first, a process of filling the seal groove 4d with liquid sealant 17 is carried out, followed by a process of inserting the annular protrusion 5d of the motor cover 5 into the seal groove 4d of the motor cover 5, and then fixing the motor cover 5 to the housing 7 at a position where the annular protrusion 5d is accommodated in the seal groove 4d. Here, when the above dimensions are set, during the process of inserting the annular protrusion 5d into the seal groove 4d, the gap between the second side wall 4d2 and the annular protrusion 5d forms an orifice-like shape with a narrower flow path area than the other parts, thereby preventing the outflow of liquid sealant 17 from the gap between the second side wall 4d2 and the annular protrusion 5d.

[0027] As a result, the liquid sealant 17 that is left in excess by the amount inserted into the annular protrusion 5d flows from the gap between the second side wall 4d2 and the annular protrusion 5d, which has a flow path area wider than the gap between the top 4d2s of the second side wall 4d2 and the motor cover 5, toward the gap between the first side wall 4d1 and the annular protrusion 5d, and then flows out from the gap between the first side wall 4d1 and the annular protrusion 5d to the outside of the sealing groove 4d, i.e., the exposed portion. In other words, the process of inserting the annular protrusion 5d into the seal groove 4d involves inserting the annular protrusion 5d into the seal groove 4d while narrowing the gap between the top 4d2s of the second side wall 4d2 and the motor cover 5 to be smaller than the gap between the annular protrusion 5d and the inner wall of the seal groove 4d, thereby causing the liquid sealant 17 to flow out from the gap between the first side wall 4d1 and the annular protrusion 5d to the outside of the seal groove 4d.

[0028] In other words, according to the above-mentioned dimension settings, the amount of liquid sealant 17 flowing out from the gap between the first side wall 4d1 and the annular protrusion 5d to the externally exposed area, i.e., the amount of liquid sealant 17 spilling out to the outside, can be intentionally made greater than the amount of liquid sealant 17 flowing out from the gap between the top 4d2s of the second side wall 4d2 and the motor cover 5 into the sealed space. Furthermore, if the amount of liquid sealant 17 flowing out to the externally exposed area can be increased, resistance to water intrusion due to destruction of the interface between the outer surface of the motor cover 5 and the liquid sealant 17 will be increased, and the improved sealing will improve the durability and reliability of the electric drive unit 101.

[0029] FIG. 6 shows that when the amount of liquid sealant 17 spilling out onto the exposed area is small, puddles that can cause damage to the interface between the outer surface of motor cover 5 and liquid sealant 17 are likely to occur. In the example shown in Figure 6, since the amount of liquid sealant 17 that spills out into the externally exposed area is small, only up to halfway through the bending diameter of the annular protrusion 5d is covered with the liquid sealant 17, and a valley-shaped portion is formed between the tip portion of the liquid sealant 17 and the bending diameter portion of the annular protrusion 5d. Furthermore, when rainwater or the like falls on the electric drive device 101 and a puddle 21 forms in the valley portion, the water accumulated in the valley portion causes salt corrosion, which destroys the interface between the outer surface of the motor cover 5 and the liquid sealant 17, allowing water to penetrate inside and causing a circuit short.

[0030] In contrast, if the amount of liquid sealant 17 flowing out to the externally exposed area is intentionally increased, the area that can become a puddle can be reduced by, for example, expanding the area of ​​the bending diameter portion of the annular protrusion 5d that is covered with the liquid sealant 17, as shown in Figure 4. Furthermore, if the formation of puddles is prevented, damage to the boundary surface caused by puddles is reduced and airtightness is maintained, thereby improving the durability and reliability of the electric drive device 101.

[0031] In addition to controlling the amount of liquid sealant 17 spilling out into the area exposed to the outside as described above, the formation of puddles can be made less likely by controlling the rise of the liquid sealant 17 exposed to the outside through setting the position of the top 4d1s of the first side wall 4d1. FIG. 7 is a partially enlarged cross-sectional view showing how the side wall height of the seal groove 4d is set so as to facilitate the spreading of the liquid sealant 17 to the outer surface side of the motor cover 5. As shown in FIG.

[0032] Here, when the height from the bottom wall 4d3 (bottom surface) of the seal groove 4d to the top 4d1s of the first side wall 4d1 is c1 and the height from the bottom wall 4d3 of the seal groove 4d to the top 4d2s of the second side wall 4d2 is c2, the seal groove 4d is formed so that c1 ≧ c2 is satisfied. In other words, the seal groove 4d is formed so that the height of the first side wall 4d1 is equal to or greater than the height of the second side wall 4d2.

[0033] By making the height of the first side wall 4d1 greater than or equal to the height of the second side wall 4d2, the liquid sealant 17 is more likely to spread toward the outer surface of the motor cover 5 due to surface tension, making it easier to raise the liquid sealant 17 to the same height as the outer surface of the motor cover 5 or higher. If the liquid sealant 17 rises to the same height as or higher than the outer surface of the motor cover 5, moisture is less likely to accumulate, and the possibility of the boundary surface being damaged can be further reduced. It is more preferable that the top portion 4d1s of the first side wall 4d1 is located higher than the position where the straight portion of the annular protrusion portion 5d changes into the bent radial portion.

[0034] In addition, by setting the position of the apex 4d1s of the first side wall 4d1 relative to the apex 4d2s of the second side wall 4d2 in the depth direction of the seal groove 4d, the liquid sealant 17 can be made to spread easily toward the outer surface side of the motor cover 5. FIG. 8 is a diagram showing the positioning of the top 4d1s of the first side wall 4d1 and the top 4d2s of the second side wall 4d2 so as to facilitate spreading of the liquid sealing agent 17 to the outer surface side of the motor cover 5. As shown in FIG.

[0035] In Figure 8, position d1 of the apex 4d1s of the first side wall 4d1 is located at the same position as position d2 of the apex 4d2s of the second side wall 4d2 in the depth direction of the seal groove 4d, or at a position farther from the bottom of the seal groove 4d than position d2 of the apex 4d2s of the second side wall 4d2. In this case too, the liquid sealant 17 easily spreads toward the outer surface of the motor cover 5 due to surface tension, making it easy to raise the liquid sealant 17 to the same height as the outer surface of the motor cover 5 or higher.

[0036] The technical ideas described in the above embodiments can be used in any suitable combination as long as no contradiction occurs. Furthermore, although the contents of the present invention have been specifically described with reference to preferred embodiments, it is obvious that a person skilled in the art can adopt various modified embodiments based on the basic technical concept and teachings of the present invention.

[0037] For example, the electric drive device 101 in the above embodiment has a motor section 1 and an electronic control section including an inverter power module 2 and a circuit board 3 that controls the motor section 1, but the present invention can be applied to an electronic control device that does not have a motor section 1 and in which the electronic control section is covered with a first exterior member and a second exterior member. Furthermore, the object controlled by the electronic control unit is not limited to a motor. In addition, the connector member 4 as the first exterior member has multiple connectors 4a, 4b, 4c protruding to the outside from the opening 8 of the motor cover 5, but the first exterior member may also be a lid-like member that covers the opening of the second exterior member. [Explanation of symbols]

[0038] 2... inverter power module (electronic control unit), 3... circuit board (electronic control unit), 4... connector member (first exterior member), 4d... seal groove, 4d1... first side wall, 4d2... second side wall, 4d3... bottom wall, 4d1s, 4d2s... top, 5... motor cover (second exterior member), 5d... annular protrusion, 17... liquid sealant, 101... electric drive unit (electronic control unit)

Claims

1. An electronic control device comprising an electronic control unit and an exterior member covering the electronic control unit, The exterior member includes a first exterior member and a second exterior member, the first exterior member has an annular seal groove filled with a liquid sealant, the second exterior member has an annular protrusion portion accommodated in the seal groove, and an apex of the second side wall of a first side wall and a second side wall that form the seal groove is covered by the second exterior member, When a distance between the first side wall and the annular protrusion is a1, a distance between the second side wall and the annular protrusion is a2, and a distance between a top of the second side wall and the second exterior member is b, a1>b and a2>b are satisfied. Electronic control unit.

2. 2. The electronic control device according to claim 1, When a height from a bottom surface of the seal groove to a top of the first side wall is c1 and a height from the bottom surface of the seal groove to a top of the second side wall is c2, c1 ≧ c2 is satisfied. Electronic control unit.

3. 2. The electronic control device according to claim 1, an apex of the first side wall is provided at the same position as an apex of the second side wall in a depth direction of the seal groove, or at a position farther from a bottom side of the seal groove than an apex of the second side wall; Electronic control unit.

4. 2. The electronic control device according to claim 1, When a distance between the tip end of the annular protrusion and the bottom surface of the seal groove is a3, the following relationships are satisfied: a1>b, a2>b, and a3>b. Electronic control unit.

5. A method for manufacturing an electronic control device including an electronic control unit and an exterior member covering the electronic control unit, The exterior member includes a first exterior member and a second exterior member, the first exterior member has an annular seal groove filled with a liquid sealant, the second exterior member has an annular protrusion portion accommodated in the seal groove, and an apex of the second side wall of a first side wall and a second side wall that form the seal groove is covered by the second exterior member, The manufacturing method includes: filling the seal groove with a liquid sealant; a step of inserting the annular protrusion into the seal groove while narrowing a gap between the top of the second side wall and the second exterior member to be smaller than a gap between the annular protrusion and an inner wall of the seal groove, thereby causing liquid sealant to flow out of the seal groove from a gap between the first side wall and the annular protrusion; A manufacturing method of an electronic control device comprising the steps of:

Images