JP5780835B2 - Electric booster - Google Patents

Description

  The present invention relates to an electric booster employed in a vehicle brake mechanism.

  In the conventional electric booster, the electric motor is driven in accordance with a command from the ECU, and the rotation from the electric motor is converted into a linear motion by the rotation / linear motion conversion mechanism and transmitted to the output member, and the output There is a structure in which a piston is driven by a member to generate a brake fluid pressure in a pressure chamber in the master cylinder, and an ECU is provided integrally with a motor housing (see Patent Document 1).

JP 2009-202867 A

  In the electric booster according to the invention of Patent Document 1 described above, one end of the bus bar is connected to the electric motor (stator) in the motor housing by a screw in the motor housing, and the other end of the bus bar is in the ECU housing. It is connected to the bus bar terminal by a mounting screw. However, if the mounting screws for the bus bar are loosened over time, there is a concern that they will fall off, and it is necessary to improve the reliability during assembly.

  It is an object of the present invention to provide an electric booster that improves reliability during assembly.

As means for solving the above-mentioned problems, the invention of the electric booster according to the present invention converts an ECU, an electric motor driven in accordance with a command of the ECU, and rotation from the electric motor into a linear motion. An ECU that includes a rotation / linear motion conversion mechanism and an output member that transmits linear motion from the rotation / linear motion conversion mechanism, wherein the electric motor is accommodated in a motor housing, and the ECU is accommodated on an outer periphery of the motor housing An electric multiplier provided with a housing, provided with a through hole in the motor housing where the ECU housing is attached, and provided with a plurality of bus bars that electrically connect the electric motor and the ECU through the through hole. in a force device, the ends of the plurality of bus bars, at the motor housing or the ECU housing, the mounting screws to the electric motor More each being mechanically and electrically connected to said motor housing or the ECU housing, the plurality of mounting screws the provided motor housing or one mounting windows for clamping from the outside of the ECU housing, the mounting window , provided with one waterproof cover for closing the mounting window in a watertight manner, waterproof cover includes a base portion, and a cylindrical fitting portion fitted to the mounting window extending from the outer periphery of the base portion A drop-off preventing portion extending from the inside of the tubular fitting portion in the base portion in the same direction as the tubular fitting portion and protruding to a position that faces the attachment screw and prevents the attachment screw from dropping off. It is characterized by providing.

  In the electric booster of the present invention, the reliability during assembly can be improved.

FIG. 1 is a cross-sectional view of an electric booster according to an embodiment of the present invention. FIG. 2 is a perspective view of the terminal block of the electric motor employed in the electric booster. FIG. 3 is an enlarged view of a main part of the electric booster. 4A and 4B show a waterproof cover, in which FIG. 4A is a side view from one side, FIG. 4B is a plan view, FIG. 4C is a side view from the other side, and FIG. It is sectional drawing which follows a line. FIG. 5 is a front view of an attachment window provided in the motor housing body of the electric booster. FIG. 6 is a front view showing a state in which a waterproof cover is attached to an attachment window provided in the motor housing body of the electric booster. FIG. 7 is an enlarged view of a main part of the electric booster employing a waterproof cover according to another embodiment. FIG. 8 shows a waterproof cover according to another embodiment, wherein (a) is a side view from one side, (b) is a plan view, (c) is a side view from the other side, and (d) is ( It is sectional drawing which follows the BB line of b).

Hereinafter, embodiments for carrying out the present invention will be described with reference to FIGS.
FIG. 1 shows a structure of an electric booster 1 according to the present embodiment. As shown in FIG. 1, the electric booster 1 includes a motor housing 3 having one end fixed to a partition wall W that partitions the engine room R1 and the vehicle compartment R2 and a tandem master cylinder 2 described later connected to the other end. ing. For convenience of explanation, the engine room R1 side is hereinafter referred to as the front side, and the vehicle compartment R2 side is referred to as the rear side.

  The motor housing 3 includes a cylindrical motor housing body 4 and a rear cover 6 that is bolted to the rear end of the motor housing body 4 and seals the opening of the rear end of the motor housing body 4 together with the seal member 5. . The tandem master cylinder 2 is fixed to the front wall 7 of the motor housing body 4 by using a stud bolt 10 and attached. The rear cover 6 is fixed to the partition wall W by using stud bolts 11. In this fixed state, a cylindrical boss portion 12 provided integrally with the rear cover 6 passes through the partition wall W and extends into the vehicle interior R2. Is issued.

  The motor housing 3 accommodates a piston assembly 14 that is shared as a primary piston of the tandem master cylinder 2 and an electric actuator 17 that drives a booster piston 16 that constitutes the piston assembly 14. On the other hand, an ECU 18 is integrally disposed on the upper portion of the motor housing 3 (the motor housing body 4 and the rear cover 6). The ECU 18 includes an ECU housing 19 for accommodating a control unit for controlling the driving of the electric actuator 17. The ECU housing 19 includes a box-shaped ECU housing body 19a and a lid 19b that closes an upper opening of the ECU housing body 19a. The ECU housing 19 has an ECU bus bar 65 (bus bar) for supplying current from the ECU 18 to the electric actuator 17 and an electric motor 53 described later from the lower surface side, that is, the surface opposite to the lid body 19b of the ECU housing body 19a. Is provided protruding. Further, a through hole 20 is formed in a portion of the upper portion of the motor housing body 4 where the ECU housing 19 is attached. An ECU housing 19 is detachably coupled so as to cover the through hole 20 of the motor housing body 4.

  A tandem master cylinder (hereinafter simply referred to as a master cylinder) 2 includes a bottomed cylinder body 21 and a reservoir 22. A secondary piston 23 that is paired with the piston assembly 14 as a primary piston is slidably disposed on the front side in the cylinder body 21. In the cylinder body 21, two pressure chambers 25 and 26 are defined by the piston assembly 14 and the secondary piston 23, and the pressure chambers 25 and 26 correspond to the advancement of the piston assembly 14 and the secondary piston 23. The brake fluid sealed inside is pumped from the discharge ports 27 and 28 provided in the cylinder body 21 to the wheel cylinder WC of the corresponding system.

  The cylinder body 21 is formed with relief ports 29 and 30 for communicating the inside of the pressure chambers 25 and 26 with the reservoir 22, and the cylinder body 21 has an inner surface on the front side of the relief ports 29 and 30, respectively. Seal members 31 and 32 are disposed. In each of the pressure chambers 25 and 26, return springs 33 and 34 that constantly urge the piston assembly 14 as the primary piston and the secondary piston 23 in the backward direction are disposed. A sleeve 38 is disposed between the annular wall 35 formed on the inner periphery of the booster piston 16 and the spring receiver of the return spring 33. Each pressure chamber 25, 26 communicates with the reservoir 22 via the relief ports 29, 30 at the retracted ends of the piston assembly 14 and the secondary piston 23, whereby the brake fluid required from the reservoir 22 is supplied to each pressure chamber 25, 26. Is replenished.

The piston assembly 14 includes a cylindrical booster piston 16 and an input piston 15 as output members. A solid input piston 15 is disposed in a cylindrical booster piston 16 so as to be movable relative thereto. The booster piston 16 is slidably fitted into a cylindrical guide 40 fitted to the front wall 7 of the motor housing body 4, and its front end extends into the pressure chamber 25 of the master cylinder 2. Yes.
On the other hand, the input piston 15 is slidably fitted into a through hole 41 of an annular wall portion 35 formed on the inner periphery of the booster piston 16, and its front end extends into the pressure chamber 25 of the master cylinder 2. Has been issued.

  A seal member 31 seals between the booster piston 16 and the cylinder body 21 of the master cylinder 2, and a seal member, that is, an annular member, between the annular wall 35 of the booster piston 16 and the input piston 15. Sealed by a cup (plunger) 42, an annular plate 43 and an O-ring 44, thereby preventing leakage of brake fluid from the pressure chamber 25 to the outside of the master cylinder 2.

  On the other hand, a diameter-expanding member 50 is connected to the rear end portion of the input piston 15, and a tip end portion of the input rod 51 interlocking with a brake pedal (not shown) is swingably connected to a spherical recess of the diameter-expanding member 50. ing. As a result, the input piston 15 moves forward and backward in the booster piston 16 by operating the brake pedal. The input rod 51 is restricted from moving rearward (in the vehicle compartment R2) by bringing the diameter-expanding member 50 into contact with an inward projection 52 formed integrally with the rear end of the cylindrical guide portion 12 of the rear cover 6. Has been. That is, in the input piston 15, the position where the diameter-expanding member 50 contacts the inward protrusion 52 of the rear cover 6 is the retracted end.

  The electric actuator 17 includes an electric motor 53 and a ball screw mechanism 54 as a rotation / linear motion conversion mechanism that converts the rotation of the electric motor 53 into a linear motion and transmits the linear motion to the booster piston 16 (output member) of the piston assembly 14. It is made up of.

  The electric motor 53 includes a stator 55 and a hollow rotor 57 that has a permanent magnet 56 disposed to face the stator 55 and rotates when the stator 55 is energized. As shown in FIGS. 1 and 2, the stator 55 is resin-molded in a form in which a plurality of stator bodies 60a made of a rectangular parallelepiped are arranged at intervals on the circumference, and a plurality of coils 60b are wound around each stator body 60a. A stator coil 60 having an annular shape as a whole, and a connection ring 61 that is welded to the rear side of the stator coil 60 and connects each phase (U phase, V phase, W phase) coil 60b from the stator coil 60. And a terminal block 62 which has a connection bus bar 63 (U phase, V phase, W phase) whose one end is fixed to the upper portion of the connection ring 61 by a mounting screw 64 and is arranged so as to straddle the stator coil 60. It consists of. The terminal block 62 is formed in a substantially block shape in which the connection bus bar 63 is integrally resin-molded, and is arranged in the motor housing body 4 substantially directly below the ECU 18 (ECU housing 19). The other end of the connection bus bar 63 is provided so as to protrude from the ECU housing 19 at a portion where the other end of the connection bus bar 63 is disposed on the front surface of the terminal block 62. Screw holes 67 into which mounting screws 66 for mechanically and electrically connecting to the ends of three ECU bus bars 65 (bus bars) extending through the through-holes 20 in total, U phase, V phase, and W phase, are screwed. Is formed.

  In the electric motor 53, the stator 55 is fixed to the motor housing body 4 with bolts 70, and the rotor 57 is rotatably supported by the motor housing body 4 and the rear cover 6 via bearings 71 and 72. The bearing 71 is disposed in a state of being fitted to the step portion of the front wall 7 of the motor housing body 4, and the bearing 72 is provided to be fitted to the step portion of the rear cover 6.

  The ball screw mechanism (rotation / linear motion converting mechanism) 54 includes a rotor 57 that is a configuration of the electric motor 53, and a hollow screw shaft 75 that is engaged with the upper portion of the rotor 57 via a ball 76. A slit 77 extending in the axial direction is formed at the rear end portion of the screw shaft 75, and the inward projection 52 of the rear cover 6 is inserted into the slit 77. That is, the screw shaft 75 is disposed in the motor housing 3 so as not to rotate, and thus, when the rotor 57 rotates, the screw shaft 75 moves directly.

  On the other hand, a step portion 78 is provided on the inner surface of the screw shaft 75, and a flange member 79 screwed to the rear end portion of the booster piston 16 abuts on the step portion 78. Further, a return spring 80 is interposed between the flange member 79 and the cylindrical guide 40 fitted to the motor housing body 4, and the booster piston 16 always attaches the flange member 79 to the screw shaft by the return spring 80. The state of contacting with the stepped portion 78 on the 75 side is maintained. Therefore, when the screw shaft 75 moves forward according to the rotation of the nut member 75, the booster piston 16 is also moved forward by being pushed by the screw shaft 75. In the present embodiment, the screw shaft 75 is positioned at a retracted end that abuts the start end of the slit 77 against the inward projection 52 on the rear cover 6 side when the brake is not operated. When the brake is not actuated, it is positioned at the retracted end to be brought into contact with the stepped portion 78 of the screw shaft 75 at the retracted end. A presser spring 81 is interposed between the screw shaft 75 and the cylindrical guide 40 to urge the screw shaft 75 rearward and restrict the screw shaft 75 from advancing inadvertently.

  Further, a pair of balance springs 85 and 85 are disposed between the booster piston 16 and the input piston 15 constituting the piston assembly 14. The pair of balance springs 85 and 85 serve to hold the booster piston 16 and the input piston 15 at the neutral position of relative movement when the brake is not operated.

  A potentiometer (not shown) for detecting the absolute displacement of the input piston 15 with respect to the vehicle body is provided at a predetermined location in the passenger compartment R2 through the operation of the input rod 51 (or brake pedal). On the other hand, a resolver 86 that detects the absolute displacement of the booster piston 16 relative to the vehicle body from the rotational displacement of the electric motor 53 is disposed in the motor housing 3. The resolver 86 includes a resolver stator 86 a that is bolted to the rear cover 6, and a resolver rotor 86 b that is disposed on the outer peripheral surface of the rotor 57 of the electric motor 53.

  The ECU bus bar 65 that protrudes from the ECU housing 19 extends into the motor housing 3 through the through hole 20 of the motor housing body 4 in a state where the ECU housing 19 is attached to the upper portion of the motor housing 3, and ends thereof. The portion is arranged so as to overlap the other end of the connection bus bar 63 of the terminal block 62 of the electric motor 53. In this state, the end of the ECU bus bar 65 and the other end of the connection bus bar 63 are fixed to the front surface of the terminal block 62 by mounting screws 66 (three corresponding to each phase). . By fixing the mounting screw 66, the electric motor 53 and the ECU 18 are electrically connected, and current is supplied from the ECU 18 to the electric motor 53.

  Further, on the front side of the motor housing body 4 of the motor housing 3, that is, the surface side to which the tandem master cylinder 2 is attached, each mounting screw 66 is provided at a portion facing the other end of the connection bus bar 63 of the terminal block 62. And a mounting window 101 for tightening each mounting screw 66 into the screw hole 67 of the terminal block 62 is formed by a tool. The attachment window 101 is fitted with a waterproof cover 100a having a drop-off prevention portion that closes the attachment window 101 in a watertight manner and prevents the attachment screw 66 from dropping off.

  Specifically, as shown in FIGS. 1 and 3, the mounting window 101 has a recess 103 provided on the outer peripheral surface of the wall 102 of the motor housing body 4 facing the other end of the connection bus bar 63 of the terminal block 62. And a fitting hole 104 provided at the bottom of the recess 103. The concave portion 103 has an oval shape in plan view that accommodates the plate-like base portion 105 of the waterproof cover 100a, and the depth thereof is set to be greater than the thickness of the plate-like base portion 105 plus the outer diameter of the O-ring 110. Is done. The shape of the fitting hole 104 in plan view is formed in an oval shape so that a cylindrical fitting portion 106 of a waterproof cover 100a described later is fitted.

  As shown in FIGS. 3 and 4, the waterproof cover 100 a has a plate-like base portion 105 having an oblong shape in plan view and an opening having an oblong shape in plan view extending from the outer peripheral portion of one surface of the plate-like base portion 105. A cylindrical fitting portion 106, and a columnar portion 107 provided at three locations inside the cylindrical fitting portion 106 at intervals in the longitudinal direction and projecting in the same direction as the cylindrical fitting portion 106 Composed. An annular groove 111 to which the O-ring 110 is mounted is formed on the outer peripheral surface of the base of the cylindrical fitting portion 106. In addition, four notch portions 112 that open upward are formed at intervals in each of the opposing linear portions of the cylindrical fitting portion 106, and three rod-like wall portions 113 are formed between the notch portions 112. Forming. A claw portion 114 projects outwardly from the outer peripheral surface of the tip portion of each bar-like wall portion 113. The height of each cylindrical portion 107 is formed to be lower than the height of the cylindrical fitting portion 106, and the tip thereof is formed to face the head of each mounting screw 66.

  3 and 5, the end of the ECU bus bar 65 extending from the ECU 18 through the through hole 20 of the motor housing body 4 is connected to the other end of the connection bus bar 63 of the terminal block 62 of the electric motor 53. Each mounting screw 66 (three screws corresponding to each phase) is inserted from the mounting window 101 provided in the motor housing body 4 and is connected to the end of the ECU bus bar 65 and the other end of the connection bus bar 63. By inserting and screwing into each screw hole 67 of the end base 62, the end portion of the ECU bus bar 65 and the other end portion of the connection bus bar 63 are fastened together to electrically and mechanically connect the two. To do.

  Here, in the thing of the said patent document 1, the electrical connection of ECU and an electric motor is performed by screwing the bus bar which protruded from the motor housing to the terminal block in ECU housing with an installation screw. Thus, in order to screw the mounting screw in the ECU housing, it is necessary to remove the lid of the ECU housing, and it is necessary to pay close attention to prevent dust and the like from adhering to the electronic device of the ECU. There is. Therefore, in the present embodiment, as described above, the ECU bus bar 65 is provided so as to protrude from the ECU housing 19 and the ECU 18 and the electric motor 53 are electrically connected within the motor housing body 4. There is no need to remove the lid 19b of the housing 19, the manufacture of the electric booster is facilitated, and the reliability at the time of assembly to the ECU can be improved.

  Thereafter, an O-ring 110 is mounted in advance on an annular groove 111 provided on the outer peripheral surface of the cylindrical fitting portion 106 of the waterproof cover 100a, and the mounting provided on the motor housing body 4 as shown in FIGS. The tip of the cylindrical fitting part 106 of the waterproof cover 100a with an O-ring is inserted into the fitting hole 104 of the window 101, and the claw part 114 provided on each rod-like wall part 113 is hooked on the fitting hole 104, and the attachment window A waterproof cover 100 a is assembled to 101. As a result, as shown in FIG. 3, the attachment window 101 is watertightly closed by the O-ring 110 of the waterproof cover 100 a, and the plate-like base portion 105 of the waterproof cover 100 a is accommodated in the recess 103 of the attachment window 101. In addition, the position of the tip of each cylindrical portion 107 of the prevention cover 100a is close to the head of each mounting screw 66, and the distance between the tip of each cylindrical portion 107 and the head of each mounting screw 66 is the screw hole of the mounting screw 66. It is arranged at a position that is shorter (smaller) than the screwing length to 67. Thereby, even when each mounting screw 66 is loosened, each mounting screw 66 is prevented from falling off by each columnar portion 107 as a falling-off preventing portion of the prevention cover 100a.

Next, the waterproof cover 100b which concerns on other embodiment is demonstrated based on FIG.7 and FIG.8.
The waterproof cover 100b includes an elongated plate-like base portion 115 having a mounting screw hole 120 in each of the protruding portions 121 protruding from both ends of the rectangular main body portion 122 in plan view, and the plate-like base portion 115. A cylindrical fitting portion 116 having an oval opening in a plan view extending from the outer peripheral portion of one surface, and provided in three locations at intervals in the longitudinal direction inside the cylindrical fitting portion 116. It is comprised from the cylindrical part 117 protrudingly provided in the same direction as the fitting part 116. FIG. An annular groove 111 to which the O-ring 110 is attached is formed on the outer peripheral surface of the base of the cylindrical fitting portion 116. The height of each columnar part 117 is formed higher than the height of the cylindrical fitting part 116.

  On the other hand, the attachment window 130 includes a recess 131 for accommodating the plate-like base portion 115 of the waterproof cover 100b, a fitting hole 132 provided in the bottom of the recess 131, and a waterproof cover 100b provided in the bottom of the recess 131. And a screw hole (not shown) for screwing the plate-like base portion 115.

  Then, as shown in FIG. 7, the end of the ECU bus bar 65 is connected to the other end of the connection bus bar 63 of the terminal block 62 of the electric motor 53 by the mounting screw 66, and then the fitting hole 132 of the mounting window 130. In addition, the tip of the cylindrical fitting portion 116 of the waterproof cover 100b with an O-ring is inserted, an attachment screw (not shown) is inserted into each attachment screw hole 120 of the plate-like base portion 115, and at the bottom of the recess 131. The waterproof cover 100b is assembled to the mounting window 130 by screwing into the provided screw holes. As a result, the plate-like base portion 115 of the waterproof cover 100 b is accommodated in the recess 131 of the attachment window 130, and the tip of each columnar portion 117 of the prevention cover 100 b comes into contact with the head of each attachment screw 66. Thereby, loosening of each attachment screw 66 is suppressed, and by extension, each attachment screw 66 is prevented from falling off.

  And in this electric booster 1, when the input rod 51, ie, the input piston 15, moves forward in response to the depression of the brake pedal, the movement is detected by the potentiometer. Then, in response to the signal from the potentiometer, an activation command is output from the ECU 18 to the electric motor 53, whereby the rotor 57 of the electric motor 53 rotates, and the rotation is converted into a linear motion by the ball screw mechanism 54. It is transmitted to the booster piston 16. That is, the input piston 15 and the booster piston 16 are integrally advanced (promoted), and depending on the input thrust applied from the brake pedal to the input piston 15 and the booster thrust applied from the electric motor 53 to the booster piston 16. The brake fluid pressure is generated in the pressure chambers 25 and 26 in the master cylinder 2. At this time, when the rotation of the rotor 57 of the electric motor 53 is controlled by the ECU 18 so that relative displacement does not occur between the input piston 15 and the booster piston 21, a pair interposed between the input piston 15 and the booster piston 16. The balance springs 85, 85 maintain the neutral position. The boost ratio at this time is uniquely determined by the area ratio between the pressure receiving area of the booster piston 16 and the pressure receiving area of the input piston 15 because the relative displacement amount is zero.

  When the booster piston 16 is relatively displaced from the neutral position in a direction (front side) in which the brake fluid pressure is increased by the booster thrust, the boost ratio (braking force) is increased, and the brake assist operation by the electric motor 53 is realized. At this time, the reaction force to the brake pedal tends to increase as the brake fluid pressure increases, but depending on the relative displacement of the booster piston 16 to the front side, the rear side of the pair of balance springs 85, 85 (brake Since the urging force of the balance spring 85 on the pedal side increases, the increase in the pedal reaction force is offset by this urging force. On the other hand, when the booster piston 16 is relatively displaced from the neutral position in the direction (rear side) in which the brake fluid pressure is reduced by the booster thrust, the boost ratio (braking force) is reduced and regenerative cooperative operation during regenerative braking is realized. To do. At this time, the pedal reaction force tends to decrease as the brake fluid pressure decreases, but depending on the relative displacement of the booster piston 16 to the rear side, the front side (master cylinder 2 side) of the pair of balance springs 85, 85. ) Of the balance spring 85 is increased, and the decrease in the pedal reaction force is offset by this urging force. That is, since the pedal reaction force is adjusted by the biasing force of the pair of balance springs 85, 85, the uncomfortable feeling of brake operation is eliminated.

  As described above, in the electric booster 1 according to the embodiment of the present invention, first, the end of the ECU bus bar 65 extending from the ECU 18 through the through hole 20 of the motor housing body 4 is connected to the terminal block of the electric motor 53. Each mounting screw 66 is inserted into the mounting window 101 (130) provided in the motor housing body 4 so as to overlap the other end of the connection bus bar 63 of 62, and the other end of the ECU bus bar 65 and the other end of the connection bus bar 63. The end portions of the ECU bus bar 65 and the other end portion of the connection bus bar 63 are electrically and mechanically connected by being inserted into the end portions and screwed into the respective screw holes 67 of the terminal block 62. Thereafter, the tip of the cylindrical fitting portion 106 (116) of the waterproof cover 100a (100b) with the O-ring is inserted into the fitting hole 104 (132) of the attachment window 101 (130), and the attachment window 101 (130). The waterproof cover 100a (100b) is assembled to the frame. As a result, the tip of each cylindrical portion 107 (117) of the prevention cover 100a (100b) is disposed at a position close to or in contact with the head of each mounting screw 66. This prevents the mounting screws 66 from falling off.

  In this embodiment, the mounting window 101 (130) is formed on the front side of the motor housing body 4. However, the present invention is not limited to this, and the mounting window 101 (130) is formed on the side surface of the motor housing body 4 or the rear cover 6. Also good. The mounting window 101 (130) may be formed in the ECU housing 19, and in this case, the bus bar is formed so as to protrude from the motor housing body 4 through the through hole 20 and extend into the ECU housing 19. .

DESCRIPTION OF SYMBOLS 1 Electric booster, 2 Tandem master cylinder (master cylinder), 3 Motor housing, 4 Motor housing main body, 6 Rear cover, 14 Piston assembly, 16 Booster piston (output member), 17 Electric actuator, 18 ECU, 19 ECU housing , 20 Through-hole, 53 Electric motor, 54 Ball screw mechanism (rotation linear motion conversion mechanism), 62 Terminal block, 63 Connection bus bar, 65 ECU bus bar (bus bar), 66 Mounting screw, 100a, 100b Waterproof cover, 101, 130 Mounting Window, 105, 115 Plate-shaped base part, 106, 116 Cylindrical fitting part, 107, 117 Cylinder part (drop-off prevention part)

Claims (2)

ECU, electric motor driven in accordance with command from ECU, rotation / linear motion conversion mechanism for converting rotation from electric motor into linear motion, and output member for transmitting linear motion from rotation / linear motion conversion mechanism And comprising
The electric motor is housed in a motor housing;
An ECU housing that houses the ECU is attached to the outer periphery of the motor housing,
A through hole is provided in the motor housing where the ECU housing is attached,
In the electric booster provided with a plurality of bus bars that electrically connect the electric motor and the ECU through the through hole,
The ends of the plurality of bus bars are mechanically and electrically connected to the electric motor by mounting screws in the motor housing or the ECU housing, respectively .
The motor housing or the ECU housing is provided with one mounting window for tightening the plurality of mounting screws from the outside of the motor housing or the ECU housing,
The installation window is provided with one waterproof cover for watertightly closing the installation window,
The waterproof cover includes a base portion, a cylindrical fitting portion extending from an outer peripheral portion of the base portion and fitting into the mounting window, and the cylindrical fitting from the inside of the cylindrical fitting portion in the base portion. An electric booster characterized in that a drop-off prevention portion is provided that extends in the same direction as the portion and protrudes to a position that faces the attachment screw and prevents the attachment screw from dropping off. The waterproof cover, the tubular fitting portion is formed to extend to a position surrounding the head of the mounting screw, the disengagement prevention part includes a feature that you have been shorter than the tubular fitting portion The electric booster according to claim 1.

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