JP2011223644A - Assembly method of control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control apparatus which is capable of shortening the time required for assembly and reducing the time and efforts required for assembly.SOLUTION: An ECU 12 includes a synthetic resin holding member 76, a thick part 59a of a first housing 23 as a heat sink, and a power substrate 49 held between the holding member 76 and the thick part 59a. When ECU12 is assembled, the power substrate 49 is disposed in a first positioning part 102 formed in the holding member 76 and in such a state, the power substrate 49 is fixed to the holding member 76 using a first dummy wire 121 or the like. Next, first and second bus bars held by the holding member 76 and cathode and anode terminals formed in a power circuit 52 are connected by first and second bonding wires. The thick part 59a of the first housing 23 is fixed to the holding member 76 thereafter.

Description

  The present invention relates to a method for assembling a control device.

  For example, an electric power steering device including an electric motor for assisting steering includes a control device that controls the electric motor (see, for example, Patent Document 1). The control device includes a circuit board such as a power board that supplies driving power to the electric motor. Various elements are mounted on the circuit board. For example, Patent Document 2 discloses a sensor mounted on a circuit board.

JP 2009-188123 A JP 2006-250550 A

  The power board of Patent Document 1 is electrically connected to a bus bar connected to a battery of the vehicle, and driving power is supplied from this bus bar. Moreover, since the power substrate has switching elements such as FETs, it generates heat. This heat needs to be released to the outside through the heat sink. As a configuration for this purpose, a configuration is conceivable in which a power board is sandwiched between a resin frame and a heat sink, and the frame and the heat sink are fixed with screws or the like.

  As a method of assembling the control device having such a configuration, for example, first, (1) the power board is fixed to the frame with an adhesive. Thereafter, (2) the bus bar fixed to the frame and the power board are connected by wire bonding. Thereafter, (3) the parts on the power substrate are embedded with a resin molding agent, and the resin molding agent is cured. After the resin molding agent is cured, (4) the frame and the power board are fixed to the heat sink with screws.

However, in such an assembling method, it takes time until the adhesive for fixing the frame and the power board is cured in the step (1). In addition, it takes time to handle the adhesive having tackiness.
Therefore, it is preferable not to use an adhesive for mounting the power board. However, also in patent document 2, the board | substrate and the sensor are being fixed with the adhesive agent.

  The present invention has been made under such a background, and an object of the present invention is to provide a control device that can shorten the time required for assembly and can reduce the time required for assembly. .

  In order to achieve the above object, the present invention provides a circuit board (49) including an electric circuit (52), and metal members (78, 78) electrically connected to the electric circuit via bonding wires (93 to 97). 79, 116, 117, 118), a holding member (76) for holding the circuit board and the metal member, and a heat sink (59a) attached to the holding member for releasing heat of the circuit board, In the assembling method of the control device (12) in which the power board is arranged between the holding member and the heat sink, the circuit board is arranged in the positioning portion (102) formed in the holding member. An arranging step, a fixing step of fixing the circuit board to the holding member using dummy wires (121 to 124), the metal member held by the holding member, and the electric A connecting step of connecting pads (86, 87, 113, 114, 115) formed on the path with bonding wires; and an attaching step of attaching the heat sink to the holding member. 1).

The dummy wire is a wire that mechanically connects the metal member and the circuit board but does not electrically connect the metal member and the electric circuit.
According to the present invention, since the circuit board can be fixed to the holding member with the dummy wire in the fixing step, no adhesive is required for fixing the holding member and the circuit board. Thereby, the waiting time until the adhesive is dried and hardened becomes unnecessary, and the time required for assembly of the control device can be shortened. In addition, since it is not necessary to use an adhesive that is troublesome to handle, less time is required for assembling the control device.

In the present invention, a step portion (101) is formed on one side surface (83h) of the holding member so as to be recessed with respect to the one side surface, and the positioning portion is disposed on the step portion, In the arrangement step, the positioning portion and the circuit board may contact each other along a thickness direction (W1) of the circuit board (claim 2).
In this case, the circuit board can be positioned with respect to the holding member by a simple operation of abutting the circuit board against the positioning portion formed on the stepped portion of the holding member. Thereby, the time and labor required for assembling the control device can be reduced.

In the present invention, the circuit board includes a dummy pad (132, 136, 138) insulated from the electric circuit. In the fixing step, the dummy wire includes the dummy pad and the metal member (78). 79) (Claim 3).
In this case, a metal member can be used as a member for fixing the dummy wire. As a result, there is no need to provide a dedicated part for fixing the dummy wire, so the number of parts can be reduced. Therefore, the cost for manufacturing the control device can be reduced.

  In the present invention, the placing step, the fixing step, and the connecting step are performed with the mounting surface (49a) on which the electric element (53) is mounted in the circuit board facing upward. In some cases, a mounting step of filling the mounting surface of the circuit board with a molding agent (147) and a curing step of curing the molding agent may be included between the mounting step and the mounting step.

  Usually, in the filling process and the curing process, it is necessary to keep the mounting surface upward in order to fill and cure the molding agent on the mounting surface of the circuit board. Therefore, if the mounting surface of the circuit board is faced up in the placement process, the fixing process, and the connection process prior to the filling process, the process of rearranging the circuit board and the holding member after the connection process can be omitted. This can reduce the time and labor required for manufacturing the control device.

  For example, as described above, when the power board and the frame are fixed with an adhesive, the power board is bonded with the power board placed on the frame so that the FET mounting surface of the power board faces downward. It is conceivable to cure the adhesive between the surface and the adhesive surface of the frame. In this case, it is necessary to turn the power substrate and the frame upside down so that the FET mounting surface of the power substrate faces upward, and then apply a resin molding agent to the mounting surface of the power substrate. Therefore, the time required for assembling the control device is increased by the upside down operation.

On the other hand, in the present invention, as described above, since the mounting surface of the circuit board is previously arranged upward, there is no need to change the vertical direction of the power board prior to filling with the molding agent, and the control device The time and labor required for manufacturing can be reduced.
In the present invention, the dummy wire may be formed of a material harder than the bonding wire (claim 5). In this case, since the dummy wire is hard, the holding member and the circuit board can be firmly connected by the dummy wire. Therefore, the mechanical load on the bonding wire can be reduced. Thereby, it is possible to reduce a load such as vibration acting on the bonding wire. In particular, when the control device is applied to a vehicle steering device, the control device is used in an environment with a lot of vibration, but the load received by the bonding wire due to the vibration is reduced. Therefore, the present invention is suitable for application to a vehicle steering apparatus.

  In addition, in the above, the numbers in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

It is a mimetic diagram showing a schematic structure of an electric power steering device concerning one embodiment of the present invention. It is a schematic perspective view of a steering assist mechanism. It is sectional drawing of the principal part of an electric power steering device. It is a typical exploded perspective view of the principal part of ECU. It is a top view of a power board and a unit. It is typical sectional drawing of the principal part in alignment with the VI-VI line of FIG. 5, and the power circuit is simplified and shown in figure. It is sectional drawing which shows the connection state of a 1st bus bar and a power board. It is an enlarged view of the frame part of FIG. It is a perspective view for demonstrating assembly | attachment of ECU, and shows the process of attaching the coil, relay, 1st capacitor | condenser, and 2nd capacitor | condenser as an electric element to a holding member. (A) And (B) is sectional drawing which shows the arrangement | positioning process which arrange | positions a power board with respect to a holding member. It is sectional drawing which shows the fixing process which fixes a power board to a holding member. It is a top view which shows the connection process which connects each pad part of a power circuit, and the corresponding pad part hold | maintained at the holding member. (A) is sectional drawing which shows the filling process which fills the main surface of a power board with a resin mold agent, (B) is sectional drawing which shows the hardening process which hardens a resin mold agent. (A) And (B) is sectional drawing which shows the attachment process which attaches a holding member and a power board to the thick part of a 1st housing.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of an electric power steering apparatus 1 according to an embodiment of the present invention.
Referring to FIG. 1, an electric power steering apparatus 1 includes a steering wheel 2 as a steering member, a steering mechanism 4 that steers a steered wheel 3 in conjunction with rotation of the steering wheel 2, and steering of a driver. And a steering assist mechanism 5 for assisting. The steering wheel 2 and the steering mechanism 4 are mechanically coupled via a steering shaft 6 and an intermediate shaft 7.

In the present embodiment, a description will be given according to an example in which the steering assist mechanism 5 applies assist force (steering assist force) to the steering shaft 6. However, the present invention can also be applied to a structure in which the steering assist mechanism 5 applies an assist force to a pinion shaft described later, or a structure in which the steering assist mechanism 5 applies an assist force to a rack shaft described later.
The steering shaft 6 includes an input shaft 8 connected to the steering wheel 2 and an output shaft 9 connected to the intermediate shaft 7. The input shaft 8 and the output shaft 9 are connected via a torsion bar 10 so as to be relatively rotatable on the same axis.

  A torque sensor 11 disposed around the steering shaft 6 detects the steering torque input to the steering wheel 2 based on the relative rotational displacement amounts of the input shaft 8 and the output shaft 9. The torque detection result of the torque sensor 11 is input to an ECU (Electronic Control Unit) 12 as a control device. Further, the vehicle speed detection result from the vehicle speed sensor 90 is input to the ECU 12. The intermediate shaft 7 connects the steering shaft 6 and the steering mechanism 4.

The steered mechanism 4 includes a rack and pinion mechanism including a pinion shaft 13 and a rack shaft 14 as a steered shaft. A steered wheel 3 is connected to each end of the rack shaft 14 via a tie rod 15 and a knuckle arm (not shown).
The pinion shaft 13 is connected to the intermediate shaft 7. The pinion shaft 13 rotates in conjunction with the steering of the steering wheel 2. A pinion 16 is provided at the tip (lower end in FIG. 1) of the pinion shaft 13.

  The rack shaft 14 extends linearly along the left-right direction of the automobile. A rack 17 that meshes with the pinion 16 is formed in the middle of the rack shaft 14 in the axial direction. By the pinion 16 and the rack 17, the rotation of the pinion shaft 13 is converted into the axial movement of the rack shaft 14. The steered wheel 3 can be steered by moving the rack shaft 14 in the axial direction.

When the steering wheel 2 is steered (rotated), this rotation is transmitted to the pinion shaft 13 via the steering shaft 6 and the intermediate shaft 7. The rotation of the pinion shaft 13 is converted into an axial movement of the rack shaft 14 by the pinion 16 and the rack 17. Thereby, the steered wheel 3 is steered.
The steering assist mechanism 5 includes an electric motor 18 for assisting steering, and a speed reduction mechanism 19 as a transmission mechanism for transmitting the output torque of the electric motor 18 to the steering mechanism 4. The speed reduction mechanism 19 includes a worm shaft 20 as a drive gear and a worm wheel 21 as a driven gear that meshes with the worm shaft 20. The speed reduction mechanism 19 is accommodated in the gear housing 22.

The worm shaft 20 is connected to a rotating shaft (not shown) of the electric motor 18 through a joint (not shown). The worm shaft 20 is rotationally driven by the electric motor 18. Further, the worm wheel 21 is connected to the steering shaft 6 so as to be integrally rotatable.
When the electric motor 18 rotationally drives the worm shaft 20, the worm wheel 21 is rotationally driven by the worm shaft 20, and the worm wheel 21 and the steering shaft 6 rotate integrally. The rotation of the steering shaft 6 is transmitted to the pinion shaft 13 via the intermediate shaft 7. The rotation of the pinion shaft 13 is converted into the axial movement of the rack shaft 14. Thereby, the steered wheel 3 is steered. That is, the steered wheels 3 are steered by rotating the worm shaft 20 by the electric motor 18.

  The electric motor 18 is controlled by the ECU 12. The ECU 12 controls the electric motor 18 based on the torque detection result from the torque sensor 11, the vehicle speed detection result from the vehicle speed sensor 90, and the like. Specifically, the ECU 12 determines a target assist amount using a map in which the relationship between the torque and the target assist amount is stored for each vehicle speed, and controls the assist force generated by the electric motor 18 to approach the target assist amount. To do.

FIG. 2 is a schematic perspective view of the steering assist mechanism 5. Referring to FIG. 2, a housing H for housing ECU 12 as a control device is configured by a first housing 23 and a second housing 24 that are in contact with each other.
The first housing 23 and the second housing 24 are each formed in a substantially square box shape with one end opened. The ends of the first and second housings 23 and 24 are abutted and fastened to each other by a fixing screw 25.

On the other hand, the motor housing 26 of the electric motor includes a cylindrical motor housing main body 27 and the first housing 23 described above.
The gear housing 22 includes a cylindrical drive gear housing 28 that houses the worm shaft 20, a tubular driven gear housing 29 that houses the worm wheel 21, and the second housing 24. Has been.

FIG. 3 is a cross-sectional view of the main part of the electric power steering apparatus 1. Referring to FIG. 3, the first housing 23 and the second housing 24 form a housing chamber 32 that houses the ECU 12 as a control device.
The first housing 23 includes a first inner wall surface 33 that defines a part of the accommodation chamber 32, and the second housing 24 includes a second inner wall surface 34 that defines a part of the accommodation chamber 32, and these first inner wall surfaces 33 and the second inner wall surface 34 face the axial direction X1 of the rotating shaft 35 of the electric motor 18.

  The rotating shaft 35 and the worm shaft 20 of the electric motor 18 are arranged coaxially side by side, and both are coaxially connected via a joint 36 so that power can be transmitted. The worm shaft 20 is supported at both ends by the drive gear housing 28 via the first bearing 37 and the second bearing 38. The rotary shaft 35 is rotatably supported by a third bearing 46 held by the first housing 23 and a fourth bearing 47 held by the motor housing body 27.

In the present embodiment, a brushless motor is used as the electric motor 18. The electric motor 18 includes the motor housing 26, and a rotor 39 and a stator 40 accommodated in the motor housing 26. The rotor 39 is connected to the rotary shaft 35 so as to be integrally rotatable.
The stator 40 is fixed to the inner periphery of the motor housing body 27 of the motor housing 26. The stator 40 includes a stator core 41 fixed to the inner periphery of the motor housing main body 27 and a plurality of coils 42. Stator core 41 includes an annular yoke of stator core 41 and a plurality of teeth protruding radially inward from the inner periphery of this yoke. Each coil 42 is wound around a corresponding tooth.

  Further, in the motor chamber 43 defined by the motor housing body 27 and the first housing 23 of the motor housing 26, an annular or C-shaped bus bar 45 is accommodated. The coil 42 wound around each tooth is connected to the bus bar 45. The bus bar 45 is a conductive connection material used for a connection portion between each coil 42 and a power board 49 described later. The bus bar 45 functions as a power distribution member for distributing power from the power board 49 to each coil 42.

The first housing 23 includes a partition wall 59 that partitions the accommodation chamber 32 and the motor chamber 43 as a bottom wall. The partition wall 59 is provided with the first inner wall surface 33.
Further, a cylindrical portion 48 extending from the partition wall 59 toward the second housing 24 side is formed. An outer ring of the third bearing 46 is held on the inner periphery of the cylindrical portion 48.
In the accommodation chamber 32, a power board 49 and a control board 50 that constitute a part of the ECU 12 are accommodated and held. A power board 49 as a circuit board is mounted with at least a part of a power circuit for driving the electric motor 18 (for example, a switching element such as an FET 53). The bus bar 45 connected to each coil 42 is connected to the power board 49 via the bus bar terminal 51 that passes through the partition wall 59 of the first housing 23 and enters the housing chamber 32.

  In the accommodation chamber 32, the power board 49 is disposed relatively close to the first inner wall surface 33 among the first inner wall surface 33 and the second inner wall surface 34. The partition wall 59 having the first inner wall surface 33 includes a thick portion 59a and a relatively thin portion 59b that are relatively thick in the axial direction X1 of the rotating shaft 35 of the electric motor 18. The thick portion 59a is provided so as to protrude into the accommodation chamber 32. The power board 49 is arranged in contact with the first inner wall surface 33 in the thick part 59a. The thick part 59 a is a seat part that receives the power board 49.

In the present embodiment, the power board 49 is in contact with the first inner wall surface 33 in the thick part 59a so as to be able to conduct heat, and the thick part 59a is for releasing the heat of the power board 49. It functions as a heat sink.
The control board 50 is disposed between the second inner wall surface 34 of the second housing 24 and the power board 49 with respect to the axial direction X1 of the rotating shaft 35 of the electric motor 18. The power board 49 and the control board 50 are arranged at a predetermined interval with respect to the axial direction X1 of the rotating shaft 35 of the electric motor 18.

  Next, referring to FIG. 4, which is a schematic exploded perspective view of the main part of the ECU 12, a power circuit 52 as an electric circuit for driving the electric motor 18 is mounted on the power board 49. . The power circuit 52 mounted on the power substrate 49 includes a plurality of FETs 53 (electrolytic effect type transistors) as heat generating elements (two FETs 53 are shown in FIG. 4). The power substrate 49 is composed of a multilayer substrate in which an electric element such as an FET 53 is mounted on the main surface 49a, and the multilayer substrate is a high thermal conductive plate (for example, an aluminum plate) that is in surface contact with the thick portion 59a as a heat sink. (Not shown). The main surface 49a is a mounting surface on which an electric element such as the FET 53 is mounted on the power substrate 49.

  A control circuit 54 for controlling the power circuit 52 is mounted on the control board 50. The control circuit 54 includes a driver that controls each FET 53 of the power circuit 52 and a CPU that controls the driver. Further, first connectors 55 and 56 are arranged on one side edge of the control board 50. A control signal from the torque sensor 11 (see FIG. 1) or the like is input to the control board 50 via the first connectors 55 and 56.

  The first housing 23 is a substantially square box-shaped member having one end opened. Specifically, the first housing 23 includes a substantially annular outer peripheral wall 57, a rectangular annular flange 58 projecting radially outward from one end of the outer peripheral wall 57, and the partition wall as a bottom wall. 59. A cylindrical portion 48 is formed in the central portion of the partition wall 59 in the storage chamber 32. The outer peripheral wall 57 extends from the outer peripheral edge of the partition wall 59 and surrounds the tubular portion 48.

  The flange 58 has a plurality of (in the present embodiment, a pair) bracket-like attachment portions 60 and 61 projecting outward in the radial direction. The mounting portions 60 and 61 are formed with screw insertion holes 62 and 63 that penetrate the mounting portions 60 and 61 in the thickness direction. The fixing screws 25 for fastening the first and second housings 23 and 24 are inserted into the screw insertion holes 62 and 63, respectively.

The outer peripheral wall 57 that forms a quadrangular ring has four side walls 71 to 74. The mounting portions 60 and 61 are extended from a pair of opposite side walls 72 and 74. Further, the thick part 59a of the partition wall 59 functioning as a heat sink is continuously formed on the inner surface of one side wall 74 where the mounting part 61 is extended.
The side wall 71 is formed with a notch 71a. The first connectors 55 and 56 extend outward from the first housing 23 through the notch 71a.

  FIG. 5 is a plan view of the power board 49 and the unit 75. With reference to FIGS. 4 and 5, a unit 75 is disposed between the control board 50 and the partition wall 59. The unit 75 has a structure in which various electric elements are collectively held by resin. As a result, a plurality of electric elements can be assembled to the first housing 23 in a lump, so that the labor required for assembling each electric element into the first housing 23 can be reduced.

The unit 75 includes a holding member 76 made of synthetic resin, a second connector 77 provided on the holding member 76, a first bus bar 78 and a second bus bar 79 as metal members held by the holding member 76, and a holding member. A coil 70 as an electric element held by 76, a relay 80, a first capacitor 81, and a second capacitor 82.
The holding member 76 has a substantially rectangular outer shape along the four side walls 71 to 74 of the first housing 23 when viewed along the axial direction X1. The holding member 76 has a shape surrounding the power substrate 49 and the cylindrical portion 48.

The holding member 76 includes a frame portion 83 that surrounds the periphery of the power board 49 when viewed along the axial direction X1.
The frame 83 is formed in a rectangular shape in plan view, and includes a first side 83c, a second side 83d, a third side 83e, and a fourth side 83f. The first side portion 83c and the third side portion 83e extend along the longitudinal direction Y1 of the power substrate 49, and the second side portion 83d and the fourth side portion 83f extend along the short direction Z1 of the power substrate 49. It extends. The second side portion 83d, the third side portion 83e, and the fourth side portion 83f are also outer shapes of the holding member 76, respectively.

Screw insertion holes 83a and 83b are formed in the first side 83c and the second side 83d of the frame 83, respectively. Further, screw insertion holes 49b and 49c are formed in the power board 49 at positions corresponding to the screw insertion holes 83a and 83b, respectively.
Fixing screws 84 and 85 through which the screw insertion holes 83a and 49b; 83b and 49c are inserted are screwed to screw holes 59c and 59d formed in the thick portion 59a. Thereby, the holding member 76 and the power board 49 are fixed to the first housing 23. A screw insertion hole 76 a is formed in the holding member 76 in the vicinity of the second connector 77. A fixing screw 69 that is inserted through the screw insertion hole 76 a is screwed to the screw hole 59 e of the thin portion 59 b of the first housing 23.

FIG. 6 is a schematic cross-sectional view of the main part taken along the line VI-VI in FIG. 5, and the power circuit 52 is illustrated in a simplified manner. With reference to FIG. 6, the power board 49 is disposed between the frame portion 83 of the holding member 76 and the thick portion 59 a of the first housing 23.
A recess 100 that is recessed with respect to the lower surface 83 h is formed on the lower surface 83 h as one side surface of the frame portion 83. The bottom surface of the recess 100 constitutes a step portion 101. The step portion 101 is formed in, for example, a first side portion 83c, a second side portion 83d, a third side portion 83e, and a fourth side portion 83f, and has an annular shape (in FIG. Of the sides 83c to 83f, only the second side 83d and the fourth side 83f are shown).

  The step portion 101 is formed in parallel with the lower surface 83h of the frame portion 83 and the surface of the thick portion 59a. A first positioning portion 102 is formed on the stepped portion 101. The first positioning portion 102 is for positioning the power substrate 49 in the thickness direction W1 when the power substrate 49 is fixed to the frame portion 83 of the holding member 76. The thickness direction W1 is parallel to the axial direction X1.

The first positioning portion 102 is in contact with the outer peripheral portion 49 d of the main surface 49 a of the power board 49. Accordingly, the first positioning portion 102 and the outer peripheral portion 49d of the main surface 49a of the power board 49 are in contact with each other along the thickness direction W1 of the power board 49.
A second positioning portion 103 is formed on the side surface 100 a of the recess 100. The second positioning unit 103 positions the power board 49 in a direction W2 orthogonal to the thickness direction W1 (a direction parallel to the main surface 49a) when fixing the power board 49 to the frame 83 of the holding member 76. Is. The outer peripheral part of the power board 49 is in contact with the second positioning part 103. A lower surface 49b (a surface opposite to the main surface 49a) of the power substrate 49 is formed by a high thermal conductive plate 104 such as an aluminum plate. The lower surface 83h is in surface contact with the surface of the thick portion 59a of the first housing 23, so that the heat of the power board 49 can be transferred to the thick portion 59a. With the above configuration, the power board 49 is disposed between the frame portion 83 and the thick portion 59 a of the holding member 76.

Referring to FIGS. 4 and 5, second connector 77 is for electrically connecting a power source such as a battery (not shown) and power board 49, and is adjacent to first connector 56. The second connector 77 includes a connector housing 77a formed integrally with the holding member 76, and a pair of terminals 77b and 77c disposed in the connector housing 77a.
The connector housing 77 a protrudes outward of the first housing 23 through the notch 71 b of the side wall 71. The terminal 77b is connected to the positive electrode of a vehicle battery (not shown). A first bus bar 78 is connected to the terminal 77b. The terminal 77c is grounded to the vehicle body. A second bus bar 79 is connected to the terminal 77c.

As shown in FIG. 5, the first bus bar 78 is a bus bar that electrically connects the terminal 77 b and the positive electrode terminal 86 as a pad formed in the power circuit 52 of the power board 49. The second bus bar 79 is a bus bar that electrically connects the terminal 77 c and a negative electrode terminal 87 as a pad formed in the power circuit 52 of the power board 49.
Each of the first bus bar 78 and the second bus bar 79 is formed in a strip shape as a whole using a metal member as a conductive member. Most of the first bus bar 78 and the second bus bar 79 are embedded in the holding member 76.

  The first bus bar 78 is connected to the relay 80. The relay 80 is provided to cut off the current flowing through the electric motor as necessary. The first bus bar 78 is divided into a first portion 91 and a second portion 92. The first portion 91 is connected to one terminal 80 a of the relay 80. The second portion 92 is connected to the other terminal 80 b of the relay 80. The second portion 92 of the first bus bar 78 includes the first pad portion 111 exposed on the upper surface 83 g of the holding member 76. The first pad portion 111 is disposed on the first side portion 83c of the frame portion 83 of the holding member 76, and is formed in a rectangular shape in plan view.

  FIG. 7 is a cross-sectional view showing a connection state between the first bus bar 78 and the power board 49. As shown in FIG. 7, the first bus bar 78 and the positive terminal 86 of the power circuit 52 of the power board 49 are connected by wire bonding. Specifically, one end of a plurality of first bonding wires 93 is bonded to the first pad portion 111 of the first bus bar 78 (only one first bonding wire 93 is shown in FIG. 7). The other end of each first bonding wire 93 is bonded to the positive terminal 86 of the power board 49. Thereby, the first bus bar 78 and the positive terminal 86 (power circuit 52) of the power board 49 are electrically connected.

  Referring to FIG. 5, second bus bar 79 includes a second pad portion 112 exposed on upper surface 83 g of holding member 76. The second pad portion 112 is disposed adjacent to the first pad portion 111 on the first side portion 83 c of the frame portion 83 of the holding member 76. The second pad portion 112 is formed in a rectangular shape in plan view, and is adjacent to the negative electrode terminal 87 formed on the main surface 49 a of the power substrate 49. The negative terminal 87 is formed in the power circuit 52.

  The connection mode between the second bus bar 79 and the negative electrode terminal 87 of the power board 49 is the same as the connection mode between the first bus bar 78 and the positive electrode terminal 86. Specifically, one end of a plurality of second bonding wires 94 is bonded to the second pad portion 112 of the second bus bar 79. The other end of each second bonding wire 94 is bonded to the negative terminal 87 of the power board 49. Thereby, the second bus bar 79 and the negative terminal 87 of the power circuit 52 of the power board 49 are electrically connected.

  The second portion 92 of the first bus bar 78 includes a pair of capacitor connection portions 78 a and 78 b that protrude from the holding member 76. The second bus bar 79 includes a pair of capacitor connecting portions 79 a and 79 b protruding from the holding member 76. These capacitor connecting portions 78 a, 78 b, 79 a, 79 b are arranged adjacent to the first pad portion 111 and the second pad portion 112.

The first capacitor 81 and the second capacitor 82 are for removing ripples of the current flowing through the electric motor 18, respectively, and are connected to the first bus bar 78 and the second bus bar 79.
The first capacitor 81 includes a capacitor main body 81a fixed to the holding member 76 and a pair of terminals 81b and 81c protruding from the capacitor main body 81a. The pair of terminals 81b and 81c of the first capacitor 81 are fixed to the capacitor connecting portions 78a and 79a by welding or the like, respectively.

The second capacitor 82 includes a capacitor main body 82a fixed to the holding member 76, and a pair of terminals 82b and 82c protruding from the capacitor main body 82a. The pair of terminals 82b and 82c of the second capacitor 82 are fixed to the capacitor connecting portions 78b and 79b by welding or the like, respectively.
Referring to FIG. 8 which is an enlarged view of the frame portion 83 in FIG. A pad portion 115 is formed. The third pad portion 113, the fourth pad portion 114, and the fifth pad portion 115 are adjacent to the fourth side portion 83f of the frame portion 83. The fourth side portion 83f holds a sixth pad portion 116, a seventh pad portion 117, and an eighth pad portion 118 as metal members.

  The sixth pad portion 116, the seventh pad portion 117, and the eighth pad portion 118 are exposed at the upper surface 83g of the holding member 76, respectively. The third pad portion 113, the fourth pad portion 114, and the fifth pad portion 115 are connected to the sixth pad portion 116, the seventh pad portion 117, and the eighth pad portion 118, respectively, by wire bonding. That is, the third pad portion 113, the fourth pad portion 114, and the fifth pad portion 115 are respectively connected to the sixth pad portion 116, the seventh pad portion 117, and the eighth pad portion 118 and the plurality of bonding wires 95, 96, and 97. Are electrically connected.

The sixth pad portion 116, the seventh pad portion 117, and the eighth pad portion 118 are each electrically connected to the bus bar terminal 51 (see FIG. 5) via a bus bar (not shown) embedded in the holding member 76. Yes.
Referring to FIGS. 6 and 8, the power board 49 uses the first dummy wire 121, the second dummy wire 122, the third dummy wire 123, and the fourth dummy wire 124 as four dummy wires. The frame 83 is fixed.

First, fixing of the power substrate 49 using the first dummy wire 121 will be described.
The second portion 92 of the first bus bar 78 includes a first dummy pad portion 131. The first dummy pad portion 131 is disposed on the second side portion 83 d of the frame portion 83. The first dummy pad portion 131 is formed in a rectangular shape in plan view and is exposed on the upper surface 83 g of the holding member 76.

A second dummy pad portion 132 is formed on the main surface 49 a of the power substrate 49 at a position adjacent to the first dummy pad portion 131. The second dummy pad portion 132 is a metal pad formed in a rectangular shape in plan view. The second dummy pad portion 132 is insulated from the power circuit 52.
The first dummy pad portion 131 and the second dummy pad portion 132 are fixed using wire bonding. Specifically, one end of the plurality of first dummy wires 121 is bonded to the first dummy pad portion 131, and the other end of each first dummy wire 121 is bonded to the second dummy pad portion 132. The first dummy wire 121 is formed of a material harder than the bonding wires 93 to 97 through which a current flows. Specifically, each of the bonding wires 93 to 97 is an aluminum wire, while the first dummy wire 121 is a copper wire.

With the above configuration, the power board 49 is held (fixed) on the second side portion 83 d via the first dummy wire 121. Since the first dummy wire 121 is insulated from the power circuit 52, no current flows.
Next, fixing of the power board 49 using the second dummy wire 122 will be described.
A third dummy pad portion 133 is provided on the fourth side portion 83 f of the frame portion 83. The third dummy pad portion 133 is formed separately from the first and second bus bars 78 and 79, for example, and is exposed on the upper surface 83g of the holding member 76. The third dummy pad portion 133 may be integrally formed with the first bus bar 78 or the second bus bar 79. The third dummy pad portion 133 is a metal member formed in a rectangular shape in plan view.

A fourth dummy pad portion 134 is formed on the main surface 49 a of the power substrate 49 at a position adjacent to the third dummy pad portion 133. The fourth dummy pad portion 134 is formed in the same manner as the second dummy pad portion 132. The fourth dummy pad portion 134 is insulated from the power circuit 52.
The third dummy pad portion 133 and the fourth dummy pad portion 134 are fixed using wire bonding. Specifically, one end of each of the plurality of second dummy wires 122 is bonded to the third dummy pad portion 133, and the other end of each second dummy wire 122 is bonded to the fourth dummy pad portion 134. The second dummy wire 122 is formed using the same material as the first dummy wire 121.

With the above configuration, the power board 49 is held (fixed) on the fourth side portion 83 f via the second dummy wire 122. Since the second dummy wire 122 is insulated from the power circuit 52, no current flows.
The second dummy wire 122 is disposed adjacent to the sixth pad portion 116, the seventh pad portion 117, and the eighth pad portion 118. Thereby, in the vicinity of the third to fifth bonding wires 95 to 97 through which a large current flows, the strength of the mechanical connection between the power substrate 49 and the holding member 76 (strength against vibration) can be increased. Therefore, it can suppress that a stress acts on each said bonding wire 95-97.

Next, fixing of the power substrate 49 using the third dummy wire 123 will be described with reference to FIG.
A fifth dummy pad portion 135 is provided in the second portion 92 of the first bus bar 78. The fifth dummy pad portion 135 is exposed on the upper surface 83 g of the holding member 76 at the second side portion 83 d of the frame portion 83. The fifth dummy pad portion 135 is formed in a rectangular shape in plan view.

A sixth dummy pad portion 136 is formed on the main surface 49 a of the power substrate 49 at a position adjacent to the fifth dummy pad portion 135. The sixth dummy pad portion 136 is formed in the same manner as the second dummy pad portion 132. The sixth dummy pad portion 136 is insulated from the power circuit 52.
The fifth dummy pad portion 135 and the sixth dummy pad portion 136 are connected using wire bonding. Specifically, one end of each of the plurality of third dummy wires 123 is bonded to the fifth dummy pad portion 135, and the other end of each third dummy wire 123 is bonded to the sixth dummy pad portion 136. The third dummy wire 123 is formed using the same material as the first dummy wire 121.

With the above configuration, the power board 49 is held (fixed) on the second side portion 83 d via the third dummy wire 123. Since the third dummy wire 123 is insulated from the power circuit 52, no current flows.
Next, fixing of the power board 49 using the fourth dummy wire 124 will be described. The second bus bar 79 is provided with a seventh dummy pad portion 137. The seventh dummy pad portion 137 is formed integrally with the second pad portion 112 using a single material, and is exposed to the upper surface 83g of the holding member 76 at the first side portion 83c of the frame portion 83. Yes. The seventh dummy pad portion 137 is formed in a rectangular shape in plan view.

An eighth dummy pad portion 138 is formed on the main surface 49 a of the power substrate 49 at a position adjacent to the seventh dummy pad portion 137. The eighth dummy pad portion 138 is formed in the same manner as the second dummy pad portion 132. The eighth dummy pad portion 138 is insulated from the power circuit 52.
The seventh dummy pad portion 137 and the eighth dummy pad portion 138 are connected using wire bonding. Specifically, one end of each of the plurality of fourth dummy wires 124 is bonded to the seventh dummy pad portion 137, and the other end of each fourth dummy wire 124 is bonded to the eighth dummy pad portion 138. The fourth dummy wire 124 is formed using the same material as the first dummy wire 121.

With the above configuration, the power substrate 49 is held (fixed) on the first side portion 83 c via the fourth dummy wire 124. Since the fourth dummy wire 124 is insulated from the power circuit 52, no current flows.
The first and second bonding wires 93 and 94 are disposed between the third dummy wire 123 and the fourth dummy wire 124. Thereby, the strength of the mechanical connection between the power substrate 49 and the holding member 76 can be increased in the vicinity of the first and second bonding wires 93 and 94 through which a large current flows. Therefore, it is possible to suppress the stress from acting on the first and second bonding wires 93 and 94.

Referring to FIG. 5, connection terminals 140 and 141 for connecting the power board 49 and the control board 50 are provided on the third side 83 e of the frame 83. These connection terminals 140 and 141 extend upward from the upper surface 83g of the holding member 76 so as to electrically connect the power circuit 52 and the control circuit 54 (see FIG. 4).
Referring to FIG. 6, resin layer 143 is formed in space 142 surrounded by main surface 49 a of power substrate 49 and frame portion 83. The resin layer 143 is formed by filling the space 142 with a resin molding agent, which will be described later, and being cured by a curing device (not shown) or the like. 5 and 8 show a state in which there is no resin layer 143 for the sake of simplicity of explanation.

The above is the schematic configuration of the electric power steering apparatus 1. Next, an assembly method (manufacturing method) of the ECU 12 of the electric power steering device 1 will be described.
First, as shown in FIG. 9, a holding member 76 that holds the first bus bar 78, the second bus bar 79, the sixth to eighth pad portions 116 to 118, and the like is prepared. The first bus bar 78 and the second bus bar 79 are inserted at the time of resin molding of the holding member 76, and most of them are embedded in the holding member 76.

Electric elements mounted on the holding member 76 such as the first capacitor 81, the second capacitor 82, the coil 70, and the relay 80 are attached to the holding member 76 to form a subassembly 144.
Next, as shown in FIG. 10A, the power substrate 49 is disposed on the first positioning portion 102 of the holding member 76 (arrangement step). Specifically, first, the power board 49 is held by the jig 145 so that the main surface 49a of the power board 49 faces upward. The main surface 49 a of the power board 49 is maintained in an upward state until the power board 49 is fixed to the first housing 23.

  Next, the frame portion 83 of the holding member 76 of the subassembly 144 is disposed above the power board 49. From this state, as shown in FIG. 10B, the power board 49 is inserted into the frame portion 83 by lifting the jig 145, for example. At this time, due to the contact between the outer peripheral portion of the power substrate 49 and the second positioning portion 103 of the inner side surface 100a of the recess 100 of the frame portion 83, the power substrate 49 is in the horizontal direction (the thickness of the power substrate 49). It is positioned in the direction W2 orthogonal to the direction W1, the front-rear left-right direction). Further, as shown in FIG. 11, the power board 49 is positioned in the vertical direction (the thickness direction W1 of the power board 49) by bringing the outer peripheral portion 49d of the main surface 49a of the power board 49 into contact with the first positioning portion 102. Is done.

  In this way, the power board 49 is fixed to the holding member 76 in a state where the power board 49 is positioned with respect to the holding member 76 (first bonding process, fixing process). Specifically, the first dummy wire 121 is bonded to the first dummy pad portion 131 held by the holding member 76 and the second dummy pad portion 132 of the power board 49 using the bonding device 146.

Similarly, the second dummy wire 122 is bonded to the third dummy pad portion 133 held by the holding member 76 and the fourth dummy pad portion 134 of the power board 49 using the bonding device 146. Although not shown, the third dummy wire 123 and the fourth dummy wire 124 are joined in the same manner.
After the power board 49 is fixed to the holding member 76 by the first to fourth dummy wires 121 to 124, as shown in FIG. 12, each pad portion 86, 87, 113, 114, 115 of the power circuit 52 and the frame Corresponding pad portions 111, 112, 116, 1117, 118 held in the portion 83 are electrically connected by wire bonding (second wire bonding step, connection step).

  Specifically, the first bonding wire 93 is bonded to the first pad portion 111 of the first bus bar 78 and the positive electrode terminal 86 of the power board 49 using the bonding device 146. Similarly, the second bonding wire 94 is bonded to the second pad portion 112 of the second bus bar 79 and the negative terminal 87 of the power board 49 using the bonding device 146. Further, the third pad portion 113, the fourth pad portion 114 and the fifth pad portion 115 of the power substrate 49, and the corresponding sixth pad portion 116, seventh pad portion 117 and eighth pad portion 118 of the holding member 76, Corresponding bonding wires 95, 96, 97 are bonded using the bonding apparatus 146.

Next, as shown in FIG. 13A, the main surface 49a of the power substrate 49 is filled with a resin molding agent 147 (filling step). The resin molding agent is, for example, a thermosetting epoxy resin, has fluidity, and is filled into the space 142 on the main surface 49a by the filling device 148.
When the filling of the resin molding agent 147 into the space 142 is completed, as shown in FIG. 13B, the resin molding agent 147 is irradiated by irradiating the resin molding agent 147 with ultraviolet rays using, for example, a curing device 149. Curing (curing process). Thereby, the resin molding agent 147 becomes the resin layer 143.

  Next, the holding member 76 and the power board 49 are attached to the thick portion 59a of the first housing 23 (attachment process). Specifically, the holding member 76 and the power board 49 are lifted from the jig 145 by the clamp 150 shown in FIG. 14A and disposed above the thick portion 59 a of the first housing 23. Then, by operating the clamp 150, as shown in FIG. 14B, the holding member 76 and the power board 49 are placed on the surface of the thick portion 59a.

  In this state, for example, as shown in FIG. 4, by screwing a plurality of fixing screws 69, 84, 85 into the corresponding screw insertion holes 76a; 83a, 49b; 83b, 49c and screw holes 59e, 59c, 59d, The holding member 76 is attached (fixed) to the first housing 23. In FIG. 4, the holding member 76 and the power board 49 are spaced apart from each other. However, when attaching the fixing screws 69, 84, and 85, the holding member 76 and the power board 49 are fixed to each other. Yes.

Next, the control board 50 is disposed on the side of the holding member 76. Thereafter, the control board 50 is fixed to the first housing 23 using the fixing screws 151 to 153 in a state where the control board 50 and the connection terminals 140 and 141 are connected.
As described above, according to the present embodiment, the power substrate 49 can be fixed to the holding member 76 using the first to fourth dummy wires 121 to 124 in the fixing step. No adhesive is required for fixing to the substrate 49. Thereby, the waiting time until the adhesive is dried and hardened becomes unnecessary, and the time required for the assembly of the ECU 12 can be shortened. In addition, since it is not necessary to use an adhesive that is troublesome to handle, less time is required for assembling the ECU 12.

  Further, in the arrangement step, the first positioning portion 102 of the holding member 76 and the power substrate 49 are in contact with each other along the thickness direction W1 of the power substrate 49. Accordingly, the power substrate 49 can be positioned in the thickness direction W1 with respect to the holding member 76 by a simple operation of abutting the power substrate 49 against the first positioning portion 102 of the stepped portion 101 of the holding member 76. Thereby, the time and labor required for the assembly of the ECU 12 can be further reduced.

  Similarly, the second positioning portion 103 of the holding member 76 and the power board 49 are in contact with each other along a direction W2 orthogonal to the thickness direction W1 of the power board 49. Thereby, the power board 49 can be positioned in the direction W2 orthogonal to the thickness direction W1 with respect to the holding member 76 by a simple operation of bringing the power board 49 into contact with the second positioning portion 103 of the holding member 76. Thereby, the time and labor required for the assembly of the ECU 12 can be further reduced.

  Further, in the fixing step, the first, third and fourth dummy wires 121, 123, 124 are joined to the corresponding dummy pad portions 131, 135, 137. That is, the first bus bar 78 and the second bus bar 79 can be used as members for fixing the first, third and fourth dummy wires 121, 123, 124. As a result, there is no need to provide a dedicated part for fixing the first, third and fourth dummy wires 121, 123, and 124, so the number of parts can be reduced. Therefore, the cost for manufacturing the ECU 12 can be reduced.

Further, in assembling the ECU 12, the main surface 49a of the power board 49 faces upward from the arrangement process to the mounting process.
In the filling step and the curing step, in order to fill and cure the resin molding agent 147 on the main surface 49a of the power substrate 49, the main surface 49a of the power substrate 49 needs to face upward. Therefore, if the main surface 49a of the power substrate 49 is set upward in the arrangement step, the fixing step, and the connection step prior to the filling step, a step of rearranging the power substrate 49 and the holding member 76 upward after the connection step. Can be omitted. Thereby, the time and labor required for manufacturing the ECU 12 can be reduced.

  For example, consider the assembly of an ECU using an adhesive. As a method of assembling such an ECU, first, (1) the power board is fixed to the holding member with an adhesive. Thereafter, (2) the first and second bus bars fixed to the holding member and the power circuit are electrically connected by wire bonding. Thereafter, (3) the parts on the power substrate are embedded with a resin molding agent, and the resin molding agent is cured. Then, after the resin molding agent is cured, (4) the holding member and the power substrate are fixed to the heat sink with screws.

  Further, in the step (1), the adhesive between the adhesive surface of the power substrate and the adhesive surface of the frame is applied with the power substrate placed on the holding member so that the main surface of the power substrate faces downward. It is possible to dry and harden. In this case, it is necessary to wait for the adhesive to harden, then turn the power board and holding member upside down so that the main surface of the power board faces upward, and then apply and dry the resin molding agent on the main surface of the power board There is. Therefore, the time required for assembling the ECU becomes longer for the upside down operation.

In contrast, in the present embodiment, as described above, the main surface 49a of the power substrate 49 is previously arranged upward, so that it is not necessary to change the vertical direction of the power substrate 49 prior to the filling step. The time and labor required for manufacturing the ECU 12 can be reduced.
The main time required for assembling the ECU using the adhesive is, for example, adhesive drying time 600 (sec) + down-holding member and power board upside down time 1 (sec) = 601 ( sec).

On the other hand, the main time required for the assembly of the ECU 12 according to this embodiment is only the time for bonding the first to fourth dummy wires 121 to 124, and the bonding time 1 (sec) per dummy wire × the first time. The number of first to fourth dummy wires 121 to 124 is 8 (pieces) = 8 (sec).
Therefore, compared with the main time 601 (sec) required for assembling the ECU using the adhesive, the main time 8 (sec) required for assembling the ECU 12 according to this embodiment is 601-8. = 593 (sec) can be shortened. Thereby, the time concerning the assembly | attachment of ECU12 can be shortened markedly.

  Further, by fixing the power board 49 to the holding member 76 with the first to fourth dummy wires 121 to 124, the number of screw holes formed in the thick portion 59a of the first housing 23 can be reduced. Thereby, compared with the case where the holding member 76, the power board 49, and the thick part 59a are mutually fixed only with a screw, the contact area of the thick part 59a of the 1st housing 23 and the power board 49 can be increased. Therefore, more heat of the power board 49 can be released to the thick portion 59a (heat sink) of the first housing 23.

  The dummy wires 121 to 124 are made of a material harder than the bonding wires 93 to 97. Thereby, the holding member 76 and the power board 49 can be firmly connected by the dummy wires 121 to 124. Therefore, the mechanical load on each bonding wire 93 to 97 can be reduced. Thereby, loads such as vibrations acting on the bonding wires 93 to 97 can be reduced.

In particular, since the ECU 12 is applied to the electric power steering device 1 as a vehicle steering device, the ECU 12 is used in an environment where there is a lot of vibration. However, the load which each bonding wire 93-97 receives by vibration is reduced. Therefore, the ECU 12 is suitable for application to the electric power steering apparatus 1.
The present invention is not limited to the contents of the above-described embodiment, and various modifications can be made within the scope of the claims.

For example, in each of the above steps in the assembly of the ECU 12, the upper surface 83g of the holding member 76 and the main surface 49a of the power board 49 may be disposed downward.
In the above-described embodiment, the power board 49 is exemplified as the circuit board, but the present invention is not limited to this. The present invention may be applied to a control device including a circuit board other than the power board and a metal member such as a bus bar connected to the circuit board.

In each of the above-described embodiments, an example in which the present invention is applied to a so-called column assist type electric power steering device has been described. The present invention may be applied to other types of electric power steering devices such as electric power steering devices of the type.
Moreover, although the above-mentioned embodiment demonstrated the example in which this invention was applied to the electric power steering apparatus which outputs the output of an electric motor as steering assistance force, it is not restricted to this. For example, a transmission ratio variable mechanism that includes a transmission ratio variable mechanism capable of changing a ratio of a steered wheel turning angle to a steering angle of a steering member, and that uses an output of an electric motor to drive the transmission ratio variable mechanism, is used for vehicle steering. Even if the present invention is applied to a device, a steer-by-wire type vehicle steering device in which the mechanical connection between the steering member and the steered wheel is released and the steered wheel is steered by the output of the electric motor, etc. Good.

  Further, the present invention may be applied to other general devices other than the vehicle steering device.

  DESCRIPTION OF SYMBOLS 12 ... ECU (control apparatus), 49 ... Power board (circuit board), 49a ... Main surface (mounting surface) of power board, 52 ... Power circuit (electric circuit), 53 ... FET (electric element), 59a ... Thick wall Part (heat sink), 76 ... holding member, 78, 79 ... bus bar (metal member), 83h ... lower surface of frame part (one side surface of holding member), 86, 87 ... terminals (pads formed on an electric circuit), 93 DESCRIPTION OF SYMBOLS -97 ... Bonding wire, 101 ... Step part, 102 ... 1st positioning part (positioning part), 113-115 ... Pad part (pad formed in the electric circuit), 116-118 ... Pad part (metal member), 121 -124 ... dummy wire, 132, 136, 138 ... dummy pad part (pad of circuit board), 147 ... resin molding agent, W1 ... thickness direction.

Claims (5)

A circuit board including an electric circuit; a metal member electrically connected to the electric circuit via a bonding wire; a holding member for holding the circuit board and the metal member; and for releasing heat of the circuit board. A heat sink attached to the holding member, and a method of assembling the control device in which the power board is disposed between the holding member and the heat sink.
An arrangement step of arranging the circuit board in a positioning portion formed on the holding member;
A fixing step of fixing the circuit board to the holding member using a dummy wire;
A connecting step of connecting the metal member held by the holding member and the pad formed on the electric circuit by a bonding wire;
An attaching step of attaching the heat sink to the holding member;
A method for assembling the control device, comprising: In claim 1, a step portion is formed on one side surface of the holding member so as to be recessed with respect to the one side surface.
The positioning portion is disposed on the stepped portion;
In the arranging step, the positioning unit and the circuit board are in contact with each other along a thickness direction of the circuit board. 3. The circuit board according to claim 1, wherein the circuit board includes a dummy pad insulated from the electric circuit,
In the fixing step, the dummy wire is joined to the dummy pad and the metal member. In any one of Claims 1-3, the said arrangement | positioning process, the said fixing process, and the said connection process are performed by making the mounting surface in which the electrical element was mounted among the said circuit boards upwards,
A control device set comprising a filling step of filling the mounting surface of the circuit board with a molding agent and a curing step of curing the molding agent between the connecting step and the attaching step. Attaching method.   The method of assembling a control device according to claim 1, wherein the dummy wire is formed of a material harder than the bonding wire.

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