JP2013069737A - Electronic circuit device of electric actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent breakage of terminals 31B (terminal group 102) having no stress relaxation structure.SOLUTION: A control unit is comprised of a bus bar module 20 obtained by integrating a plurality of bus bars in a plate-like shape with a synthetic resin material, and a control substrate 21 overlappingly disposed on the bus bar module 20. The bus bar module 20 has a heavy-current power component such as a switching element mounted thereon. The control substrate 21 has a low electric power electronic component mounted thereon. The control substrate 21 is held by a plurality of locking claws 33, and is constrained in an X-direction. A plurality of pin-like terminals 31B cut and raised from a bus bar side edge extend through through-holes of the control substrate 21 and are soldered onto the control substrate 21. Some of the terminals 31B have a stress relaxation structure curved in a U-shape or the like. Although the terminals 31B of the terminal group 102 have no stress relaxation structure, they are cut and raised from the bus bar side edge along a Y-direction, and therefore are unsusceptible to breakage even when the control substrate 21 vibrates in the Y-direction.

Description

  The present invention relates to an electronic circuit device for an electric actuator used in an electric brake booster device for a vehicle.

  In recent years, an electric brake booster device in which the hydraulic pressure of a master cylinder is increased by using an electric actuator, for example, an electric motor, instead of a negative pressure type brake booster device using an internal combustion engine as a negative pressure source in a vehicle brake device has been proposed. ing.

  Patent Document 1 previously proposed by the present applicant discloses an electric brake booster device using a three-phase AC brushless motor that is concentrically centered around an input rod that moves in the axial direction in conjunction with a brake pedal as an actuator. An electronic circuit device including an inverter circuit that drives and controls the three-phase AC brushless motor, that is, a control unit is integrally mounted on the upper surface of the electric motor housing.

  The control unit includes a bus bar module in which power components are mounted and a plurality of bus bars are integrated with a synthetic resin material, and a control board formed of a printed wiring board disposed on the bus bar module. A plurality of pin-like terminals rising upward from the bus bar module are inserted into the through holes of the control board and connected to the control board by soldering.

JP 2010-132103 A

  The control board is held in a state where an appropriate gap is maintained on the bus bar module. In Patent Document 1, the control board is fixed to the bus bar module using screws. In the structure which stops, there exists a malfunction which the assembly of a control unit becomes complicated.

  On the other hand, as the control board fixing structure described above, a plurality of locking claws are formed on the bus bar module itself molded of a synthetic resin material, and these locking claws are formed on the side of the control board using the elasticity of the synthetic resin material. If a so-called snap-fit structure is adopted in which the control board is held on the bus bar module by being engaged with the edge, the control board is in the direction in which the plurality of locking claws hold the control board from both sides. However, since the restraining force in the direction orthogonal to this is weak, the control board is likely to be slightly displaced with respect to the bus bar module due to traveling vibration of the vehicle. Therefore, stress acts on the pin-shaped terminal that rises upward from the bus bar module and the tip is fixed to the control board, and may break from the connection portion with the bus bar that is the base of the terminal.

An electronic circuit device for an electric actuator according to the present invention includes:
A casing attached to the housing of the electric actuator;
A bus bar module that is arranged in the casing and mounted with power components for driving the electric actuator, and in which a plurality of bus bars are integrated with a synthetic resin material,
A plurality of terminals including a terminal that is arranged on the bus bar module and is held from both side edges by a plurality of locking claws formed integrally with the bus bar module, and is cut and raised from the bus bar so as to stand up from the bus bar module. A control board to which the terminals of are connected through a through hole;
It has.

  And the terminal connected to the said control board from the said bus bar is cut and raised from the said bus bar side edge along the direction orthogonal to the restraining direction of the said control board by the said latching claw.

  According to the present invention, since the control board arranged to be superimposed on the bus bar module is held on the bus bar module as a snap fit structure, the assembly process is simplified and the problem of the terminal which becomes a problem in the case of the snap fit structure is achieved. Breaking can be effectively suppressed by setting the direction of the cut and raised to a direction orthogonal to the constraint direction of the snap-fit structure.

The perspective view of the electric brake booster apparatus which assembled | attached the control unit to the housing of the motor unit. The exploded perspective view of the control unit of this electric brake booster device. The perspective view which shows the upper surface side of a bus-bar module. The expansion perspective view of the A section of FIG. The perspective view which shows the state which accumulated the control board on the upper surface of the bus-bar module. The perspective view which shows the lower surface side of a bus-bar module. The perspective view which shows the upper surface side of a casing. The perspective view which shows the lower surface side of a casing. Sectional drawing of the principal part along the cross section which passes along the connector for sensors. The perspective view which shows the wiring state of a bus-bar. FIG. The front view of the terminal which shows an example of a stress relaxation structure. The front view of the terminal which shows the other example of a stress relaxation structure. Sectional drawing of the principal part along the BB line of FIG.

  Hereinafter, an embodiment in which the present invention is applied to an electric brake booster device for a vehicle will be described in detail.

  FIG. 1 shows the configuration of the entire brake booster device in which the control unit 3 is assembled to the housing 2 of the motor unit 1, and FIG. 2 shows an exploded perspective view thereof.

  The motor unit 1 is attached to a bulk head (not shown) that partitions an engine room and a vehicle compartment of a vehicle body, and an input rod (not shown) that moves in the axial direction in conjunction with a brake pedal is on the right side of the figure. An electric motor (not shown) made up of a three-phase AC brushless motor that is located in the cylindrical portion 4 and is concentric with the cylindrical portion 4 is housed in the housing 2. Therefore, the housing 2 basically has a substantially cylindrical shape corresponding to the internal electric motor. A master cylinder 5 for supplying hydraulic pressure to the brake system is mounted at the center of the front end of the housing 2 that is supported in a cantilevered manner by the bulkhead. In accordance with the operated amount of the brake pedal, the electric motor can increase the pressure of the master cylinder 5.

  The housing 2 of the motor unit 1 is made of, for example, aluminum alloy die-casting, and has a controller mounting portion 7 on its upper surface (in other words, part of the circumferential surface) as shown in FIG. The controller mounting portion 7 includes an electromechanical connection chamber 9 surrounded by a peripheral wall portion 8 so as to form a substantially rectangular box shape whose upper surface is open, and a pair of flange portions 10 respectively provided on both sides thereof. A seal member 11 such as an O-ring that is continuous over the entire circumference of the electromechanical connection chamber 9 is disposed on the top of the peripheral wall portion 8. In the electromechanical connection chamber 9, three input terminals (not shown) of the electric motor connected to the three output terminals 15 on the control unit 3 side are arranged. A part of the peripheral wall 8 has a work hole 16 for connecting the output terminal 15 and the input terminal (screwing). The working hole 16 is finally closed by mounting a plug (not shown).

  As shown in FIG. 2, the control unit 3 includes a casing 18 made of a die-cast aluminum alloy or the like having a box shape with an upper surface opened, and a die-cast aluminum alloy or the like mounted in the upper surface opening of the casing 18. Or it consists of the cover 19 which consists of a sheet metal press-molded product, the bus bar module 20 accommodated in the inside which consists of these casings 18 and the cover 19, and the printed wiring board arrange | positioned on the upper surface of this bus bar module 20. The control board 21 is generally configured. The bus bar module 20 is fixed inside the casing 18 with a plurality of screws 22, and the cover 19 is covered with the casing 18 with a plurality of screws 23 so as to cover the bus bar module 20 and the control board 21. Is attached. The casing 18 is mounted on the controller mounting portion 7 with a plurality of screws 24 screwed into the flange portion 10 on the motor unit 1 side.

  3 to 6 show the bus bar module 20. The bus bar module 20 has a plurality of bus bars 31 (refer to FIGS. 10 and 11) made of a copper plate or a brass plate through which a relatively large current for driving a three-phase AC motor is driven, in a plate shape with an insulating synthetic resin material. The main connector 26 having a flat cylindrical shape formed by integrating the power connector and the control signal connector is integrally formed on one side thereof. As shown in FIGS. 3 and 5, the plurality of control signal terminals 27 that reach the control signal connector of the main connector 26 rise upward individually without being electrically connected to the bus bar 31. Each bus bar 31 has a large number of substantially rectangular terminal pieces 31A joined to the terminals of the power component and noise countermeasure component mounted on the bus bar module 20 by welding or soldering, and the control board 21. A thin pin-shaped terminal 31B for signal transmission is provided and protrudes upward from the synthetic resin portion forming the plate shape of the bus bar module 20 as shown in FIG. Here, the substantially rectangular terminal piece 31A has a short protruding length, and the pin-shaped terminal 31B has a relatively long protruding length. The plurality of bus bars 31 are arranged three-dimensionally within the thickness of the bus bar module 20 as will be described later.

  FIG. 6 shows the configuration of the bus bar module 20 on the lower surface side. As shown in FIG. 6, on the lower surface of the bus bar module 20, there are six semiconductor switching components that constitute an inverter circuit for driving a three-phase AC motor. An element (MOS-FET) 35, two relays 36 for cutting off / energizing current in the event of an abnormality, a plurality of electrolytic capacitors 37, a normal mode choke coil 38 and a common mode choke coil 39 for reducing noise in the circuit Power components such as a current detecting shunt resistor 40 and noise countermeasure components are mounted.

  An output terminal support portion 42 that rises in a wall shape from the lower surface of the bus bar module 20 is integrally formed at the center of the lower surface of the bus bar module 20, and there are three outputs of U, V, and W phases. Terminals 15 are provided in a line. These output terminals 15 pass through an output terminal opening 69 (see FIGS. 7 and 8) provided on the bottom wall of the casing 18 and are not shown in the electromechanical connection chamber 9 of the housing 2 described above. Screwed to the input terminals on the side.

  Similarly, a sensor connector 45 rising in a wall shape from the lower surface of the bus bar module 20 is integrally formed on one side of the lower surface of the bus bar module 20. The sensor connector 45 is formed by integrating a resolver connector 45A connected to an electric motor side resolver and a temperature sensor connector 45B connected to an electric motor side temperature sensor. The sensor connector opening 65 (see FIGS. 7 and 8) provided in the bottom wall of the casing 18 passes through the electromechanical connection chamber 9, and a resolver and a temperature sensor (not shown) are connected in the electromechanical connection chamber 9. A connection is made.

  The plurality of terminals in the sensor connector 45, that is, the sensor signal terminals 46 are formed into independent thin pins, and pass through the synthetic resin portion at the base of the sensor connector 45 as shown in FIG. Projecting to the upper surface side of the bus bar module 20. Although the sensor signal terminals 46 of these sensor connectors 45 are supported by the bus bar module 20, they are not electrically connected to the bus bar 31 inside the bus bar module 20.

  As shown in an enlarged view in FIG. 4, a cylindrical support portion 32 on which the control board 21 is placed, and a plurality of support portions 32 on the support portion 32, as shown in an enlarged view in FIG. A locking claw 33 having a tip swelled so as to be engaged with the peripheral edge of the control board 21 is formed. The control board 21 is formed as a so-called snap-fit structure using elastic deformation of the locking claw 33. It is supposed to be held on top. In the illustrated example, the locking claws 33 are arranged with the support portion 32 at three positions along one side edge of the control board 21, and the locking claws are formed at three positions along the other side edge so as to face this. 33 is arranged together with the support portion 32, and the control board 21 is held between the both sides by the locking claws 33 provided in the opposite directions. Therefore, the control board 21 is relatively firmly restrained in the direction in which these locking claws 33 are sandwiched from both sides (hereinafter, this will be referred to as X direction for convenience). However, in the Y direction orthogonal to the X direction, the restraining force is relatively weak, and the control board 21 is likely to be slightly displaced or vibrated along the Y direction. In addition, if it is going to restrain as a snap fit structure in both X and Y directions, the assemblability including the alignment work tends to deteriorate.

  FIG. 5 shows a state in which the control board 21 is held on the bus bar module 20 as described above. In this state, the control board 21 is placed on the bus bar module 20 so as to overlap with the upper surface of the bus bar module 20. And a plurality of support portions 32 provided adjacent to the locking claws 33 allow a gap between the upper surface of the bus bar module 20 and the terminal piece 31A to be avoided. It is secured.

  Then, several thin pin-like terminals 31B extending longer than the terminal pieces 31A, the plurality of control signal terminals 27 of the main connector 26, and the plurality of sensor signals of the sensor connector 45 are provided. Each terminal 46 is connected to the control board 21 by soldering at the tip of the terminal 46 through the through hole of the control board 21. Note that the printed circuit and various electronic components provided on the control board 21 through which a relatively small current flows are not shown.

  7 and 8 show the casing 18 combined with the bus bar module 20 as a single unit. FIG. 7 shows an upper surface of the casing 18, that is, an inner configuration in which the bus bar module 20 is accommodated. The structure of the side which covers the lower surface of the casing 18, ie, the electromechanical connection chamber 9 of the motor unit 1, is shown. As shown in these drawings, screw holes 61 into which the screws 23 (see FIG. 2) for attaching the cover 19 described above are screwed are provided at four corners of the casing 18 having a substantially rectangular shape. Holes 62 through which the screws 24 (see FIG. 2) for fixing to the above-described motor unit 1 side are respectively provided at four locations protruding outward in an ear shape. In addition, a notch 63 into which the main connector 26 of the bus bar module 20 is fitted is provided on one side of the four side walls surrounding the periphery. A heat mass portion 64 having a thick rectangular block shape is formed at a central portion of the casing 18, specifically at a position corresponding to the region of the semiconductor switching element 35 of the bus bar module 20. The heat mass portion 64 is one step higher than the surrounding bottom wall surface, and its upper surface is close to the semiconductor switching element 35 that is heated. Note that a heat dissipation sheet made of an insulating material (not shown) may be attached to the upper surface of the heat mass portion 64 so as to be in direct contact with the semiconductor switching element 35. A large number of fins 65 are formed on the outer surface of the casing 18 in order to dissipate the heat received by the heat mass portion 64. A breathing hole 66 to which a breathing filter (not shown) is attached is opened on the side wall adjacent to the heat mass portion 64, and the space inside the control unit 3 communicates with the outside through the breathing hole 66. ing. Further, as described above, the output terminal opening 69 through which the output terminal support 42 of the bus bar module 20 passes and the sensor connector 45 of the bus bar module 20 pass through the bottom wall of the casing 18. Each of the openings 70 is formed in a slit shape.

  Next, the terminals 31B, 27, and 46 connected from the bus bar module 20 to the control board 21 will be described in more detail.

  FIGS. 10 and 11 show a wiring state of a plurality of bus bars 31 integrated as the bus bar module 20. The control signal terminal 27 of the main connector 26 and the sensor signal terminal 46 of the sensor connector 45 are shown in FIG. Is also shown. As described above, a plurality of bus bars 31 are arranged in a three-dimensional manner within the thickness of the bus bar module 20, and these bus bars 31 include a terminal piece 31 </ b> A having a short protruding length that does not reach the control board 21, and And a large number of pin-like terminals 31B having a long protruding length. These short terminal pieces 31 </ b> A and pin-like terminals 31 </ b> B are both formed by cutting and raising a part of the base material of the bus bar 31.

  In addition, “cutting and raising” is a type of sheet metal processing, in which a part of a metal plate is cut along a desired shape, and then that part is bent to the base material by bending. And bending may be performed simultaneously, or both may be sequentially performed as separate steps.

  The terminal 31B cut and raised from the bus bar 31 into a thin pin shape extends upward as described above and the tip is connected to the control board 21. Generally, such a thin and long terminal is connected to the control board 21 by the control board 21. When it is vibrated by running vibration or the like, stress concentrates and there is a risk of breakage from the connecting portion with the bus bar 31 that is the base of the terminal. In particular, in the case of the bus bar 31 made of oxygen-free copper as the bus bar 31 for large current, since the hardness thereof is high, breakage easily occurs.

  In order to avoid breakage due to such stress concentration, some of the pin-like terminals 31B include a fixed end on the bus bar module 20 side (that is, the base of the terminal 31B connected to the bus bar 31) and the control board. A known stress relaxation structure 71 that relaxes stress therebetween is provided at an intermediate portion between the fixed end on the 21 side (soldering portion with the control board 21).

  As the stress relaxation structure 71, for example, as shown in FIG. 12, a substantially U-shaped structure in which a terminal 31 </ b> B extending from the side edge of the bus bar 31 to the side is bent downward and then inverted upward to a U-shape, Alternatively, as shown in FIG. 13, there is a structure in which an intermediate portion of a terminal 31 </ b> B cut upward from the side edge of the bus bar 31 is locally curved in a C shape. These two examples are realized by bending the terminal 31B cut out linearly on the side edge of the bus bar 31. In addition, although not shown, a C-shaped stress relaxation structure similar to that shown in FIG. 13 may be provided in the shape of the terminal itself cut out in a pin shape.

  The terminal 31B having the stress relaxation structure 71 as described above is, for example, a total of four terminals 31B indicated by reference numeral 101 in FIG. The terminal 31B can be cut and raised along an arbitrary direction. When the control board 21 vibrates along the Y direction where the restraining force is weak, the four terminals 31B indicated by reference numeral 101 are subjected to torsional stress at the base portion of the terminal 31B. 12 is provided, and the stress generated in the base portion is suppressed. Note that a total of twelve terminals 31B indicated by reference numeral 103 in FIG. 11 have the C-shaped stress relaxation structure 71 shown in FIG. 13, but these extend from the side edge of the bus bar 31 along the Y direction. It has been cut up. Further, a total of two terminals 31B indicated by reference numeral 104 have the U-shaped stress relaxation structure 71 shown in FIG. 12, and are cut and raised from the side edge of the bus bar 31 along the Y direction. The terminals 31B having these stress relaxation structures 71 are less likely to be broken due to slight vibrations of the control board 21, and therefore can be cut and raised from the side edges of the bus bar 31 along an arbitrary direction.

  On the other hand, some of the pin-like terminals 31B cut and raised from the bus bar 31 do not include the stress relaxation structure 71 due to processing restrictions caused by the shape or layout of the bus bar 31. However, any of the terminals 31B that do not include the stress relaxation structure 71 is cut from the side edge of the bus bar 31 along the Y direction perpendicular to the restraining direction X by the locking claws 33 described above. In the illustrated example, a total of eight terminals 31B indicated by reference numeral 102 in FIG. 11 correspond to the terminals 31B that do not have such a stress relaxation structure 71, and these terminals 31B are shown in the sectional view of FIG. Further, it is cut and raised along the Y direction from both side edges of the bus bar 31 having a strip shape. That is, the base material is bent along the Y direction, essentially has some flexibility along the Y direction, and is easily elastically deformed along the Y direction. Therefore, even if the control board 21 vibrates in the Y direction due to vehicle running vibration or the like, the base portion of the terminal 31B is subjected to stress as a bending stress along the bending process at the time of cutting and stress relaxation. Even without the structure 71, breakage is unlikely to occur.

  Further, a plurality (for example, eight) of sensor signal terminals 46 extending upward from the sensor connector 45 are independent in a pin shape and bend twice by 90 ° along the Y direction to extend in a crank shape. Therefore, this portion becomes a substantial stress relaxation structure, and even if the control board 21 vibrates in the Y direction, breakage hardly occurs. In this embodiment, a plurality of sensor signal terminals 46 are arranged in a line along the X direction with the terminal group 103 provided with the stress relaxation structure 71 described above. Therefore, when the control board 21 vibrates in the Y direction, the stress acting on the terminals 31B and 46 is dispersed, and the breakage of the terminals 31B and 46 is further suppressed.

  A plurality of (for example, 23) control signal terminals 27 extending upward from the main connector 26 are individually pin-shaped, and the distance from the fixed end on the main connector 26 side to the fixed end on the control board 21 side. Is sufficiently long, this distance is a substantial stress relaxation structure, and even if the control board 21 vibrates in the Y direction, breakage hardly occurs.

  The sensor signal terminal 46 and the control signal terminal 27 can be made of brass as a low-current signal line, and are made of material compared to the terminal 31B of the bus bar 31 using oxygen-free copper. Therefore, breakage is unlikely to occur.

  Further, in the illustrated example, the sensor signal terminals 46 are arranged in a row in the X direction along with one side of the control board 21, and the terminals of the terminal groups 101 and 103 are arranged along one side opposite to the terminal group 103. A total of four terminals 31B are similarly arranged in a row in the X direction, and a number of control signal terminals 27 are arranged in two rows in the Y direction along the other side of the control board 21. . That is, the terminals 31 </ b> B, 46, and 27 are arranged on the outer peripheral edge of the control board 21 along the three sides of the control board 21. Accordingly, the rotational moment of the control board 21 held by the plurality of locking claws 33 is more effectively suppressed. In particular, since a large number of control signal terminals 27 are arranged side by side in the Y direction, the control board 21 is restrained in the Y direction, and vibration in the Y direction where the restraining force by the locking claws 33 is weak is suppressed. In the illustrated example, since all the terminals 31B of the terminal group 102 that do not include the stress relaxation structure 71 are located near the center of the control board 21, the stress relaxation is applied to the displacement caused by the rotational moment of the control board 21. The displacement which each terminal 31B of the terminal group 102 which does not have the structure 71 receives becomes very small, and it is further advantageous in preventing the breakage.

  As described above, in the control unit 3 of the above-described embodiment, the control board 21 arranged so as to overlap the bus bar module 20 is held on the bus bar module 20 as a snap-fit structure, so that the assembly process is simplified. Then, the breakage of the terminal 31B, which is a problem in the case of the snap fit structure, can be effectively suppressed by setting the direction of the cut and raised to a direction orthogonal to the constraint direction of the snap fit structure. That is, it is possible to employ a snap-fit structure that can be easily assembled while avoiding breakage of the thin pin-shaped terminal 31B. Further, when it is difficult to provide a stress relaxation structure on the terminal 31B cut and raised from the bus bar 31 due to the shape or layout of the bus bar 31, the omission thereof is possible.

  As mentioned above, although one Example which applied this invention to the electric brake booster apparatus of the vehicle was described, this invention is not restricted to this, About electric motors other than a three-phase alternating current electric motor, or electric actuators other than a motor Can be applied similarly.

DESCRIPTION OF SYMBOLS 1 ... Motor unit 2 ... Housing 3 ... Control unit 18 ... Casing 19 ... Cover 20 ... Bus bar module 21 ... Control board 27 ... Terminal 31 ... Bus bar 31A ... Terminal piece 31B ... Terminal 46 ... Terminal 71 ... Stress relaxation structure 102 ... Stress relaxation Terminal group without structure

Claims (2)

A casing attached to the housing of the electric actuator;
A bus bar module that is arranged in the casing and mounted with power components for driving the electric actuator, and in which a plurality of bus bars are integrated with a synthetic resin material,
A plurality of terminals including a terminal that is arranged on the bus bar module and is held from both side edges by a plurality of locking claws formed integrally with the bus bar module, and is cut and raised from the bus bar so as to stand up from the bus bar module. A control board to which the terminals of are connected through a through hole;
With
The terminals connected to the control board from the bus bar are cut and raised from the edge of the bus bar along a direction orthogonal to the restraining direction of the control board by the locking claw. Circuit device.   The plurality of terminals from the bus bar module to the control board include a plurality of terminals having a stress relaxation structure between a fixed end on the bus bar module side and a fixed end on the control board side. All the terminals connected to the control board from the bus bar other than the terminals having a relaxation structure are cut and raised from the bus bar side edge along a direction orthogonal to the restraining direction. The electronic circuit device of the electric actuator according to claim 1.

Images