JP2016113060A - Electric power steering device and electronic control unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power steering device which secures electromagnetic shield property of a control board for controlling driving of an electric motor and reduces vibrations of a second housing serving as a cover, and to provide an electronic control unit.SOLUTION: An electric control unit 2 includes: a first conductive housing 3; a second conductive housing 4; and an elastic body 7. The first conductive housing 3 includes: a first frame part 33 which encloses a housing part 36 configured to house a circuit board for controlling driving of an electric motor; an edge part 33t of an outer periphery of an end surface of the first frame part 33; and a guide part 34 in which part of a surface located at the inner side of the edge part 33t protrudes. The second conductive housing 4 includes: a top plate part 41 covering one surface side of the housing part 36; a second frame part 42 of the top plate part 41 which may be fitted in the outer periphery side of the guide part 34; and claw parts 43 in which part of the second frame part 42 protrudes to the opposite side of the top plate part 41. The elastic body 7 is disposed on the edge part 33t between the first frame part 33 and the second frame part 42. The claw parts 43 are electrically connected with the first housing 3.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an electric power steering apparatus and an electronic control unit.

  Patent Document 1 discloses that a cover member includes a dynamic vibration absorber that absorbs vibration of the cover member, and the dynamic vibration absorber functions as a weight during vibration absorption, and between the mass member and the cover member. A control unit having an interposed elastic body is described. Patent Document 2 describes a vibration isolating member serving as a vibration isolating mechanism that prevents the control unit from resonating due to vibration from the electric motor on the surface having the maximum area of the protective cover. Patent Document 3 describes a steering device in which a sound absorbing material is provided in a steering column and an electronic device.

JP 2009-113609 A JP 2008-254555 A JP 2008-238829 A

  In the techniques of Patent Document 1 to Patent Document 3, an elastic member and a sound-absorbing material are arranged on the cover surface, and the area is large and functions as a weight, thereby suppressing vibration. However, in order to ensure the electromagnetic shielding property of the control board that controls the driving of the electric motor, the electronic control unit screwes the first casing that houses the control board and the second casing that covers the first casing. Therefore, there is a possibility that the vibration of the speed reducer to which the first casing is fixed or the vibration of the motor to which the first casing is fixed is directly transmitted to the second casing. is there.

  The present invention has been made in view of the above, and an electric power steering device that reduces the vibration of the second casing serving as a cover while ensuring the electromagnetic shielding property of a control board that controls the driving of the electric motor. And an electronic control unit.

  In order to solve the above-described problems and achieve the object, as an aspect of the present invention, an electric power steering apparatus includes an electric motor that applies an auxiliary steering force to a steering wheel, and drive control of the electric motor. An electronic power steering device comprising an electronic control unit, the electronic control unit comprising: a first frame portion surrounding a storage portion for storing a circuit board that controls driving of the electric motor; and an end surface of the first frame portion. A conductive first housing including an outer peripheral edge, and a guide part from which a part of the inner surface of the edge protrudes, a top plate part covering one surface side of the storage part, and the guide part A conductive second housing having a second frame portion of the top plate portion that can be fitted to an outer peripheral side of the top plate portion, and a claw portion in which a part of the second frame portion projects to the opposite side of the top plate portion. Between the body, the first frame portion and the second frame portion, Comprising an elastic body interposed part, wherein the claw portion is electrically connected to the first body.

  In order to solve the above-described problems and achieve the object, as a second aspect of the present invention, an electronic control unit is an electronic control unit for driving and controlling an electric motor that applies an auxiliary steering force to a steering wheel. A first frame portion that encloses a housing portion that houses a control board that controls driving of the electric motor, an outer peripheral edge portion of the end surface of the first frame portion, and a part of the inner surface of the edge portion. A first conductive case including a guide portion, a top plate portion covering one side of the storage portion, and a second frame portion of the top plate portion that can be fitted to the outer peripheral side of the guide portion; A part of the second frame part having a claw part protruding to the opposite side of the top plate part, and between the conductive second housing and the first frame part and the second frame part An elastic body interposed in the edge portion, and the claw portion is in electrical contact with the first housing.

  According to the first aspect and the second aspect of the present invention, the second casing is placed on the first casing via the elastic body, and the vibration of the first casing is hardly transmitted to the second casing. . And since the nail | claw part is electrically connected to the 1st housing | casing, the electromagnetic shielding property of the control board which controls the drive of an electric motor is securable.

  As a desirable aspect of the present invention, a side surface of the frame of the first housing includes a hole portion with a part of the surface recessed, and the claw portion is bent to the first housing in the hole portion. It is preferable that they are electrically connected. Thereby, even if the second housing and the first housing face each other via the elastic body, the second housing and the first housing are stably at the same potential. As a result, the electromagnetic shielding property of the control board that controls the driving of the electric motor can be ensured.

  As a desirable mode of the present invention, it is preferable that a part of the claw portion is electrically connected to the first housing by a caulking portion that is caulked together with a surface of the frame portion of the first housing. Thereby, even if the second housing and the first housing face each other via the elastic body, the second housing and the first housing are stably at the same potential. As a result, the electromagnetic shielding property of the control board that controls the driving of the electric motor can be ensured.

  As a desirable aspect of the present invention, it is preferable that the elastic body is interposed over the entire circumference of the edge. Thereby, the space | interval between the edge part of a 1st frame part and a 2nd frame part is stabilized.

  As a desirable mode of the present invention, it is preferable that the thickness of the elastic body at the edge portion is partially different and has unevenness along the outer periphery. Thereby, the quantity of an elastic body can be adjusted.

  As a desirable aspect of the present invention, it is preferable that the elastic body is partially applied to a part of the edge. Thereby, the space | interval between the edge part of a 1st frame part and a 2nd frame part can be adjusted.

  As a desirable aspect of the present invention, it is preferable that the surface of the edge portion has irregularities and the elastic body is stored in the concave portions. Thereby, the space | interval between the edge part of a 1st frame part and a 2nd frame part is stabilized.

  According to the present invention, it is possible to provide an electric power steering device and an electronic control unit that reduce the vibration of the second casing serving as a cover while ensuring the electromagnetic shielding property of the control board that controls the driving of the electric motor. it can.

FIG. 1 is a configuration diagram of an electric power steering apparatus including an electronic control unit according to the first embodiment. FIG. 2 is an explanatory view schematically showing a steering force assist mechanism around the electric motor as viewed from the direction of the rotation axis of the electric motor. FIG. 3 is an explanatory view schematically showing a steering force assist mechanism around the electric motor viewed from the direction of the input shaft. FIG. 4 is a perspective view schematically illustrating the electronic control unit according to the first embodiment. FIG. 5 is a cross-sectional view illustrating an example of a cross section of the electronic control unit of FIG. FIG. 6 is a top plan view of the first housing of the electronic control unit according to the first embodiment. FIG. 7 is a cross-sectional view illustrating an example of a cross section of the electronic control unit according to the second embodiment. FIG. 8 is a top plan view of the first housing of the electronic control unit according to the second embodiment. FIG. 9 is a partial side view for explaining the state of the elastic body of the first housing according to the second embodiment. FIG. 10 is a partial side view of the first housing according to the first modification of the second embodiment. FIG. 11 is a partial side view for explaining the state of the elastic body of the first housing according to the second modification of the second embodiment. FIG. 12 is a cross-sectional view illustrating an example of a cross section of the electronic control unit according to the third embodiment. FIG. 13 is an explanatory diagram schematically illustrating a steering force assist mechanism around the electric motor as viewed from the direction of the rotation axis of the electric motor according to the fourth embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined.

(Embodiment 1)
FIG. 1 is a configuration diagram of an electric power steering apparatus including an electronic control unit according to the first embodiment. FIG. 2 is an explanatory view schematically showing a steering force assist mechanism around the electric motor as viewed from the direction of the rotation axis of the electric motor. FIG. 3 is an explanatory view schematically showing a steering force assist mechanism around the electric motor viewed from the direction of the input shaft. An outline of an electric power steering apparatus 80 including the electric motor 10 will be described with reference to FIGS. 1 to 3.

<Electric power steering device>
The electric power steering device 80 includes a steering wheel 81, a steering shaft 82, a steering force assist mechanism 83, a universal joint 84, a lower shaft 85, a universal joint 86, in the order in which the force applied from the steering wheel is transmitted. A pinion shaft 87, a steering gear 88, and a tie rod 89 are provided. The electric power steering apparatus 80 includes an electronic control unit (hereinafter referred to as ECU (Electronic Control Unit)) 2 and a torque sensor 91a. The vehicle speed sensor 91b is provided in the vehicle, and inputs a vehicle speed signal V to the ECU 2 by CAN (Controller Area Network) communication.

  The steering shaft 82 includes an input shaft 82a and an output shaft 82b. The input shaft 82a has one end connected to the steering wheel 81 and the other end connected to the steering force assist mechanism 83 via the torque sensor 91a. The output shaft 82 b has one end connected to the steering force assist mechanism 83 and the other end connected to the universal joint 84. In the present embodiment, the input shaft 82a and the output shaft 82b are formed from a material such as iron.

  The lower shaft 85 has one end connected to the universal joint 84 and the other end connected to the universal joint 86. The pinion shaft 87 has one end connected to the universal joint 86 and the other end connected to the steering gear 88.

  Steering gear 88 includes a pinion 88a and a rack 88b. The pinion 88a is connected to the pinion shaft 87. The rack 88b meshes with the pinion 88a. The steering gear 88 is configured as a rack and pinion type. The steering gear 88 converts the rotational motion transmitted to the pinion 88a into a linear motion by the rack 88b. The tie rod 89 is connected to the rack 88b.

  The steering force assist mechanism 83 includes a speed reducer 92 and an electric motor (motor) 10. The electric motor 10 may be a so-called brushless motor, or may be an electric motor including a brush (slider) and a commutator (commutator). The reduction gear 92 is connected to the output shaft 82b. The electric motor 10 is an electric motor that is connected to the reduction gear 92 and generates auxiliary steering torque. In the electric power steering device 80, a steering column is constituted by the steering shaft 82, the torque sensor 91a, and the speed reducer 92. The electric motor 10 gives auxiliary steering torque to the output shaft 82b of the steering column. That is, the electric power steering apparatus 80 of this embodiment is a column assist system.

  In the column assist type electric power steering device 80, the distance between the steering wheel and the electric motor 10 is relatively short, and the electric motor 10 is disposed near the feet of the steering wheel in the vehicle interior. The sound generated in the vicinity of the electric motor 10 may be amplified and affect the steering person. For this reason, in the electric power steering apparatus 80, suppressing the sound generated in the vicinity of the electric motor 10 contributes to a more comfortable assist operation.

  The speed reducer 92 shown in FIGS. 2 and 3 is, for example, a worm speed reducer. The rotational force of the electric motor 10 is transmitted to the worm wheel via the worm inside the speed reducer 92 and rotates the worm wheel. The reduction gear 92 increases the torque of the electric motor 10 by the worm and the worm wheel. Then, the reduction gear 92 rotates the output shaft 82b and gives an auxiliary steering torque to the output shaft 82b.

  The torque sensor 91a shown in FIG. 1 detects the steering force of the steering person transmitted to the input shaft 82a via the steering wheel 81 as a steering torque. The vehicle speed sensor 91b detects the traveling speed (vehicle speed) of the vehicle on which the electric power steering device 80 is mounted. The ECU 2 is electrically connected to the electric motor 10, the torque sensor 91a, and the vehicle speed sensor 91b. The ECU 2 controls the operation of the electric motor 10.

  Moreover, ECU2 acquires a signal from each of the torque sensor 91a and the vehicle speed sensor 91b. That is, the ECU 2 acquires the steering torque T from the torque sensor 91a, and acquires the vehicle speed signal V of the vehicle from the vehicle speed sensor 91b. The ECU 2 is supplied with electric power from a power supply device (for example, an in-vehicle battery) 99 in a state where the ignition switch 98 is on. The ECU 2 calculates an assist steering command value of the assist command based on the steering torque T and the vehicle speed signal V. Then, the ECU 2 adjusts the current value supplied to the electric motor 10 based on the calculated auxiliary steering command value via the bus bar unit 30.

  The steering force of the driver (driver) input to the steering wheel 81 is transmitted to the speed reduction device 92 of the steering force assist mechanism 83 via the input shaft 82a. At this time, the ECU 2 acquires the steering torque T input to the input shaft 82a from the torque sensor 91a, and acquires the vehicle speed signal V from the vehicle speed sensor 91b. The ECU 2 controls the operation of the electric motor 10. The auxiliary steering torque created by the electric motor 10 is transmitted to the speed reducer 92.

  The steering torque (including auxiliary steering torque) output via the output shaft 82 b is transmitted to the lower shaft 85 via the universal joint 84 and further transmitted to the pinion shaft 87 via the universal joint 86. The steering force transmitted to the pinion shaft 87 is transmitted to the tie rod 89 via the steering gear 88 to steer the steered wheels.

  As shown in FIGS. 2 and 3, the ECU 2 is directly attached to the speed reducer 92 so that the heat generated by the ECU 2 can be dissipated by the speed reducer 92.

  The electric motor 10 and the ECU 2 are fixed via a reduction gear 92. Note that the ECU 2 may be fixed to the reduction gear 92 via the electric motor 10. The bus bar unit 30 is an electric motor connection structure according to the present embodiment, and is for electrically connecting an electric motor side terminal of the electric motor 10 and an equipment side terminal of the ECU 2 that is an equipment. Next, the ECU 2 will be described.

<ECU>
FIG. 4 is a perspective view schematically illustrating the electronic control unit according to the first embodiment. FIG. 5 is a cross-sectional view illustrating an example of a cross section of the electronic control unit of FIG. FIG. 6 is a top plan view of the first housing of the electronic control unit according to the first embodiment. Here, FIG. 5 shows an A1-A2 cross section of FIG. As shown in FIG. 4, the ECU 2 includes a first housing 3 and a second housing 4 and can contain a control board described later.

  As shown in FIGS. 4 and 5, the first housing 3 includes a bottom portion 31 and a first frame portion 33 that is erected from the periphery of the bottom portion 31 and serves as an outer wall. The first frame portion 33 includes an edge portion 33t on the outer periphery of the end surface, and a guide portion 34 from which a part of the inner surface of the edge portion 33t protrudes at the end on the second housing 4 side (upper side). The thickness W1 between the outer side surface 33F and the inner side surface 33I of the first frame portion 33 is wider than the thickness W2 between the outer side surface 34F and the inner side surface 34I of the guide portion 34 immediately above it. A cutout portion 35 is provided on the outer side surface 33F of the first frame portion 33, and a depth W4 from the outer side surface 33F of the first frame portion 33 is defined by a second frame portion 42 of the second casing 4 described later. The thickness is equal to or less than W3 and is longer than the length obtained by (W1-W2).

  The first housing 3 is a metal body that is integrally manufactured by aluminum die casting and has conductivity. Since the 1st housing | casing 3 is manufactured by aluminum die-casting, it is excellent in electromagnetic shielding property and can make the inner surface shape of the accommodating part 36 into a desired shape. For example, the first housing 3 may be provided with a step at the bottom 31. When the first housing 3 is integrally manufactured by aluminum die casting, the first housing 3 is excellent in heat dissipation and acts as a heat sink.

  As shown in FIG. 6, the guide portion 34 is continuously formed along the entire circumference of the first frame portion 33. The guide part 34 may be partially formed along the edge part 33 t of the first frame part 33.

  There are four notches 35 according to the first embodiment, but the number is not limited. As shown in FIGS. 4 and 5, a depth W5 deeper than the depth W4 of the notch 35 is provided at a position closer to the bottom 31 than the notch 35 on the outer surface 33F of the first frame 33. A hole 39 is provided.

  As shown in FIGS. 4 and 5, the second housing 4 called an ECU cover includes a top plate portion 41 and a second frame portion 42 that stands from the periphery of the top plate portion 41 and serves as an outer wall. In the second housing 4, the top plate portion 41 and the second frame portion 42 are integrally formed by pressing a sheet of steel plate. The second frame portion 42 is fitted to the outside of the guide portion 34 with the outer side surface 34F of the guide portion 34 as a guide surface, and faces the edge portion 33t of the first frame portion 33. The second housing 4 has a claw portion 43 in which a part of the second frame portion 42 protrudes on the opposite side of the top plate portion 41. As shown in FIGS. 4 and 5, the claw portion 43 passes through the notch portion 35 and reaches the hole portion 39.

  The ECU 2 includes a control circuit having a first control board 21, a second control board 22, and a relay connector 23. The ECU 2, the first control board 21, and the second control board 22 are housed in the housing portion 36 and are fixed to the first housing 3 by screws or the like. Further, the ECU 2 has a terminal (not shown) connected to the above-described torque sensor 91a, and a terminal (not shown) connected to the bus bar unit 30 on the end face adjacent to the electric motor 10.

  The second casing 4 is a member that covers the first casing 3, and has a width W41 that is approximately the same as the width W31 of the first casing 3, as shown in FIG. Also in the direction orthogonal to the direction shown in FIG. 5, the second housing 4 has a width approximately equal to the width of the first housing 3. The second housing 4 is formed of a conductive metal such as a steel plate, for example. The second housing 4 suppresses external electromagnetic waves from reaching the first control board 21 or the second control board 22 and causes the external electromagnetic waves to generate noise in the first control board 21 or the second control board 22. To suppress that. Thus, since the second housing 4 acts as an electromagnetic shield, it needs to be at the same potential as the first housing 3.

  The first control board 21 is referred to as a so-called power board, and is fixed directly via a heat dissipating grease with the bottom 31 of the first housing 3 as an attachment part. The first control board 21 is an H bridge circuit configured by an electronic component 20 such as a power switching element such as a field effect transistor for driving and controlling the electric motor 10 on a metal board having high thermal conductivity. This is a substrate on which a pulse width modulation circuit for driving the electronic component 20 such as a power switching element of a bridge circuit is mounted.

  The second control board 22 is a board on which a micro control unit (MCU: Micro Control Unit) for controlling a steering assist force generated by the electric motor 10 and its peripheral devices are mounted. The micro control unit includes a CPU (Central Processing Unit), a memory for storing a program, and an input / output circuit for the CPU and the memory. The second control board 22 calculates a steering assist current command value based on the torque detection value from the torque sensor 91 a and the vehicle speed detection value from the vehicle speed sensor 91 b, and outputs the steering assist current command value to the electric motor 10. Based on the detected value of the motor current, current feedback control is performed to calculate a voltage command value to the pulse width modulation circuit of the first control board 21. Here, the second control board 22 is an electronic circuit in which various electronic components 20 are mounted on the board. On the second control board 22, electronic components that realize various functions including the above-described circuits are mounted on the board. The electronic components mounted on the first control board 21 and the second control board 22 include electronic parts without leads such as BGA (Ball Grid Array) and CSP (Chip Size Package). In addition, on the first control board 21 and the second control board 22, electronic parts other than electronic parts without leads, for example, electronic parts with lead terminals having lead terminals can be mounted.

  The claw portion 43 of the second housing 4 described above comes into contact with the surface or side surface of the hole 39 on the top plate portion 41 side to become a conducting portion 6 and is electrically connected to the first housing 3. The claw portion 43 has a bent portion B when contacting the side surface of the hole portion 39. For example, as shown in FIG. 4, the width T <b> 1 of the claw portion 43 is smaller than the width T <b> 2 of the hole portion 39, and the claw portion 43 having the bent portion B is inserted into the hole portion 39. As described above, the outer surface 33F of the first frame portion 33 of the first housing 3 includes the hole portion 39 in which a part of the surface is recessed, and the claw portion 43 has the bent portion B and is bent, It is in electrical contact with the first housing 3 in the hole 39. Thus, the second housing 4 has the same potential as the first housing 3 due to the claw portion 43, and can act as an electromagnetic shield.

  As described above, the first housing 3 is disposed in the vicinity of the steering force assist mechanism 83 and, for example, vibrations are easily transmitted from the reduction gear 92 and the electric motor (motor) 10. However, between the first frame portion 33 and the second frame portion 42, the elastic body 7 interposed at the edge portion 33t is interposed. The elastic body 7 is an insulating synthetic rubber, elastomer, adhesive, or the like, and has a braking or damping action. As a result, the second housing 4 is placed on the first housing 3 via the elastic body 7, and the vibration of the first housing 3 is not easily transmitted to the second housing 4. The elastic body 7 may be made conductive by adding a powder such as carbon or a conductive metal material, a filler, or the like to a polymer composition such as a synthetic rubber, an elastomer, or an adhesive. Since the elastic body 7 has conductivity, the first frame portion 33 and the second frame portion 42 are electrically connected to each other, and the electromagnetic shielding property can be improved.

  As shown in FIG. 5, the elastic body 7 is provided between the first frame portion 33 and the second frame portion 42, that is, not only the second frame portion 42 and the edge portion 33t, It is also interposed between the outer side surface 34F of the guide portion 34. The elastic body 7 is applied to the edge 33t shown in FIG. 6 over the entire circumference. Thereby, the space | interval between the edge part 33t of the 1st frame part 33 and the 2nd frame part 42 is stabilized. Further, the distance between the edge portion 33t of the first frame portion 33 and the second frame portion 42 can be adjusted according to the application amount of the elastic body 7. The operating noise of the second housing 4 can be reduced by shifting the resonance point by changing the distance between the edge 33t of the first frame 33 and the second frame 42.

  As described above, the ECU 2 includes the first housing 3 and the second housing 4. The first housing 3 is formed of conductive aluminum die cast, and includes a first frame portion 33 that surrounds a storage portion 36 that stores the first control board 21 and the second control board 22 that control the driving of the electric motor 10. The peripheral edge part 33t of the outer periphery of the end surface of the 1st frame part 33 and the guide part 34 from which the one part surface inside the edge part 33t protrudes are included. The second housing 4 includes a top plate portion 41 that covers one side of the storage portion 36, a second frame portion 42 that can be fitted to the outer peripheral side of the guide portion 34, and a portion of the second frame portion 42 that is a top plate. And a claw portion 43 protruding on the opposite side of the portion 41. The elastic body 7 is interposed between the first frame portion 33 and the second frame portion 42 at the edge portion 33t. Further, the claw portion 43 is in electrical contact with the first housing 3.

  The second housing 4 of the ECU 2 ensures electromagnetic shielding as a cover for the first housing 3. Since the second housing 4 of the ECU 2 is a thin plate material as compared with the first housing 3, the second housing 4 has low rigidity and may promote vibrations and operating sounds that cause the electric power steering device 80 to operate. If the thickness of the second casing 4 of the ECU 2 is increased, it is not preferable because it increases costs and weight. Therefore, the ECU 2 according to the first embodiment applies the elastic body to the end portion of the first frame portion 33 or the end portion of the second frame portion 42 or pastes the elastic body from the first housing 3 to the second housing. By suppressing the vibration to the body 4, it is possible to suppress the generation of an unpleasant sound for the steering person or the passenger, and the steering performance is improved. And ECU2 which concerns on Embodiment 1 can reduce the vibration of the 2nd housing | casing 4 used as a cover, ensuring the electromagnetic shielding property of the control board which controls the drive of the electric motor 10. FIG.

(Embodiment 2)
FIG. 7 is a cross-sectional view illustrating an example of a cross section of the electronic control unit according to the second embodiment. FIG. 8 is a top plan view of the first housing of the electronic control unit according to the second embodiment. FIG. 9 is a partial side view for explaining the state of the elastic body of the first housing according to the second embodiment. In the ECU 2 according to the second embodiment, the elastic body 7 is partially applied to a part of the edge 33t. Note that the same components as those described in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 7, the elastic body 7 is not applied to the edge portion 33 t where the claw portion 43 is provided. Accordingly, a gap S is formed between the claw portion 43 and the outer side surface 34F of the guide portion 34. As a result, it is possible to suppress the elastic body 7 from flowing out due to surface tension between the claw portion 43 and the notch portion 35 and entering the hole portion 39. For this reason, the nail | claw part 43 can contact the 1st housing | casing 3 stably electrically.

  As shown in FIGS. 8 and 9, in the elastic body 7 according to the second embodiment, the elastic bodies 71 are scattered within the edge portion 33 t with the non-application area 72 interposed therebetween. The distance between the edge portion 33t of the first frame portion 33 and the second frame portion 42 can be adjusted according to the application amount of the elastic body 71 and the length of the non-application region. The operating noise of the second housing 4 can be reduced by shifting the resonance point by changing the distance between the edge 33t of the first frame 33 and the second frame 42.

  FIG. 10 is a partial side view of the first housing according to the first modification of the second embodiment. Note that the same components as those described in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted. As shown in FIG. 10, the edge portion 33t has a convex portion 33p and a concave portion 33q. The recess 33q can store the elastic body 71. Thereby, the application position of the elastic body 71 becomes more accurate. And the space | interval between the edge part 33t of the 1st frame part 33 and the 2nd frame part 42 is stabilized. As a result, the quality with respect to the attenuation of the operation sound of the ECU 2 can be improved.

  FIG. 11 is a partial side view for explaining the state of the elastic body of the first housing according to the second modification of the second embodiment. The elastic body 7 according to the second modification of the second embodiment includes a low film thickness region 71B having a predetermined film thickness of the elastic body 7 and a high film thickness region in which the elastic body 7 is thicker than the low film thickness region 71B. 71A is scattered in the edge portion 33t. The thickness of the elastic body is partially different and has irregularities along the outer periphery. Thereby, the application quantity of an elastic body can be adjusted.

(Embodiment 3)
FIG. 12 is a cross-sectional view illustrating an example of a cross section of the electronic control unit according to the third embodiment. The ECU 2 according to the third embodiment does not have the hole 39. Note that the same components as those described in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 12, the ECU of the third embodiment does not have the hole portion 39, so that the claw portion 43 faces the outer surface of the notch portion 35. A tool such as a punch is pressed from the vertical direction F perpendicular to the outer side surface 33F of the first frame portion 33, and a part of the claw portion 43 is plastically deformed, so that the outside of the frame portion 33 of the first housing 3 is deformed. Caulking portion 61 is formed by caulking together with the surface of side surface 33F. The caulking portion 61 has a small contact resistance between the claw portion 43 and the first frame portion 33 and becomes the conducting portion 6, and the first housing 3 and the second housing 4 can be electrically connected stably. .

(Embodiment 4)
FIG. 13 is an explanatory diagram schematically illustrating a steering force assist mechanism around the electric motor as viewed from the direction of the rotation axis of the electric motor according to the fourth embodiment. Note that the same components as those described in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted. As shown in FIG. 13, the ECU 2 of the fourth embodiment is directly attached to the electric motor 10 and may be easily subjected to vibration of the electric motor 10. Also in the ECU of the fourth embodiment, as in the other embodiments, the second housing 4 is placed on the first housing 3 via the elastic body 7, and the vibration of the first housing 3 is reduced. It becomes difficult to be transmitted to the second housing 4. The ECU 2 according to the fourth embodiment applies the elastic body to the end portion of the first frame portion 33 or the end portion of the second frame portion, or pastes the elastic body from the first housing 3 to the second housing 4. By suppressing this vibration, it is possible to suppress the generation of an unpleasant sound for the steering person or the passenger, and the steering performance is improved. The ECU according to the fourth embodiment can reduce the vibration of the second casing 4 serving as a cover while ensuring the electromagnetic shielding property of the control board that controls the driving of the electric motor 10.

2 Electronic control unit (ECU)
3 First housing 4 Second housing 6 Conducting portion 7 Elastic body 10 Electric motor 20 Electronic component 21 First control board 22 Second control board 23 Relay connector 30 Bus bar unit 31 Bottom 33t Edge 33q Concavity 33F Outer side 33p Convex Part 33I Inner side surface 33 First frame part 33 Housing 34 Guide part 34F Outer side surface 34I Inner side surface 35 Notch part 36 Storage part 39 Hole part 41 Top plate part 42 Second frame part 43 Claw part 61 Caulking part 71 Elastic body 71A High film thickness area 71B Low film thickness area 72 Non-application area 80 Electric power steering device 81 Steering wheel 82 Steering shaft 82a Input shaft 82b Output shaft 83 Steering force assist mechanism 84 Universal joint 85 Lower shaft 86 Universal joint 87 Pinion shaft 88 Steering gear 88a pinion 88b rack 8 Tie rods 91a torque sensor 91b vehicle speed sensor 92 reduction gear 98 ignition switch B bent portion

Claims (14)

An electric power steering apparatus comprising: an electric motor that applies an auxiliary steering force to a steering wheel; and an electronic control unit that drives and controls the electric motor,
Electronic control unit
A first frame portion surrounding a storage portion for storing a circuit board that controls driving of the electric motor, an outer peripheral edge portion of the end surface of the first frame portion, and a part of the inner surface of the edge portion protrude. A conductive first housing including a guide portion;
A top plate portion covering one surface side of the storage portion, a second frame portion of the top plate portion that can be fitted to an outer peripheral side of the guide portion, and a part of the second frame portion is opposite to the top plate portion A conductive second housing having a claw protruding to the side;
An elastic body interposed between the first frame part and the second frame part at the edge part,
The claw portion is an electric power steering apparatus that is electrically connected to the first casing. A side surface of the frame of the first housing includes a hole part of which the surface is recessed,
The electric power steering apparatus according to claim 1, wherein the claw portion is bent and electrically connected to the first housing in the hole portion.   2. The electric power steering apparatus according to claim 1, wherein a part of the claw portion is electrically connected to the first housing by a caulking portion that is caulked together with a surface of the frame portion of the first housing.   The electric power steering apparatus according to any one of claims 1 to 3, wherein the elastic body is interposed over the entire circumference of the edge portion.   The electric power steering device according to claim 4, wherein the thickness of the elastic body at the edge portion is partially different and has irregularities along the outer periphery.   The electric power steering apparatus according to any one of claims 1 to 3, wherein the elastic body is partially applied to a part of the edge.   7. The electric power steering apparatus according to claim 5, wherein a surface of the edge portion has irregularities, and the elastic body is stored in the concave portion. An electronic control unit for driving and controlling an electric motor that applies an auxiliary steering force to a steering wheel,
A first frame portion that surrounds a storage portion that stores a control board that controls driving of the electric motor, an outer peripheral edge portion of the end surface of the first frame portion, and a part of the inner surface of the edge portion protrude. A conductive first housing including a guide portion;
A top plate portion covering one surface side of the storage portion, a second frame portion of the top plate portion that can be fitted to an outer peripheral side of the guide portion, and a part of the second frame portion is opposite to the top plate portion A conductive second housing having a claw protruding to the side;
An elastic body interposed between the first frame part and the second frame part at the edge part,
The claw portion is an electronic control unit that is in electrical contact with the first housing. The outer surface of the frame body of the first housing includes a hole portion in which a part of the surface is recessed,
The electronic control unit according to claim 8, wherein the claw portion is bent and electrically connected to the first housing in the hole portion.   The electronic control unit according to claim 8, wherein a part of the claw portion is electrically connected to the first housing by a caulking portion that is caulked together with a surface of the frame portion of the first housing.   The electronic control unit according to claim 8, wherein the elastic body is interposed over the entire periphery of the edge portion.   The electronic control unit according to claim 11, wherein the thickness of the elastic body at the edge part is partially different, and there is unevenness along the outer periphery.   The electronic control unit according to claim 8, wherein the elastic body is partially applied to a part of the edge.   The electronic control unit according to claim 12 or 13, wherein a surface of the edge portion has irregularities, and the elastic body is stored in a concave portion.

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