JP5343950B2 - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device surely preventing the intrusion of conductive foreign matter, which adversely affects the detective operation of a torque sensor, with an inexpensive structure. <P>SOLUTION: A gear box-side sloped surface 33 is formed at the peripheral edge of an opening 20d formed in a gear box mounting surface 20b. A cover step part 34 extends outward from the cover plate part 28 of a control unit. A slit portion 28a is formed at the distal end of the cover step part 34. The outer periphery of the cover step part is formed as cover-side sloped surfaces 35a, 36a which are brought into surface-contact with the gear box-side sloped surface while surrounding the opening when the cover plate part is moved close to the gear box mounting surface so as to mount the control unit. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention provides a control unit including an electric motor that transmits a steering assist force to a steering shaft to which a steering torque is transmitted via a speed reduction mechanism in a speed reduction gear box, and a control board on which a control circuit that drives and controls the electric motor is mounted. And an electric power steering apparatus.

  As a conventional electric power steering device, for example, an electric motor is accommodated in a rack case or a reduction gear box in which a rack shaft is slidably accommodated or mounted, and a control board for controlling driving of the electric motor is accommodated. The housing is formed in a rack case or a reduction gear box, and when the control board inserted from the opening is brought into contact with a mounting boss formed on the bottom facing the opening of the housing, the electric motor projects from the electric motor. There has been proposed an electric power steering device in which board connection terminals provided on the control board are in contact with each other and electrically connected to the motor side connection terminals, and an electric connection line is provided between the electric motor and the control board. By attaching directly without insertion, electrical noise is applied with the shortest wiring length between the electric motor and the control board. It is possible to prevent, it is possible to reduce electrical losses by reducing the wiring resistance.

  However, it is necessary to input a torque detection value of a torque sensor that detects torque transmitted to the steering shaft to a control board that controls the electric motor. It is installed on the wheel side, and it is necessary to provide a long connection cable between this torque sensor and the control board. Electric noise is added to this connection cable, and electrical resistance increases, resulting in an increase in electrical loss. .

  Therefore, a mounting surface is formed on the outer periphery of the reduction gear box, and a control unit incorporating a control board is mounted on the mounting surface, and a plurality of external connection terminals connected to a torque sensor built in the reduction gear box. Projecting to the outside from the opening provided so as to open at the mounting surface in communication with the position where the torque sensor is housed, and inserted into a plurality of through holes provided on the control board of the control unit mounted on the mounting surface In addition, we have developed an electric power steering device that has a structure in which both are electrically connected by soldering, and the connection distance between the control board and the torque sensor is minimized to prevent electrical noise and electrical loss between the two. (For example, refer to Patent Document 1).

JP 2009-023459 A

  However, as described above, the mounting surface of the reduction gear box to which the control unit is mounted is provided with an opening communicating with the position where the torque sensor is accommodated, and the outside of the torque sensor connected to the control board from this opening. If the connection terminal is protruded and connected to the through hole of the control board, conductive foreign matter enters from the gap between the reduction gearbox mounting surface and the control unit mounting surface, and is connected to any external part of the torque sensor. There is a possibility that the connection terminals come into contact with each other, the torque sensor outputs an erroneous torque detection value, and the electric motor performs erroneous drive control.

Here, it is difficult in terms of manufacturing cost to form the mounting surface and the mounting surface with high accuracy so that there is no gap between the mounting surface of the reduction gear box and the mounting surface of the control unit.
Therefore, the present invention has been made paying attention to the unsolved problems of the above-described conventional example, projecting the external connection terminal of the torque sensor from the gear box mounting surface to the outside, and connecting it to the control board of the control unit, To provide an electric power steering device that can reliably prevent intrusion of conductive foreign matters and the like that adversely affect the detection operation of a torque sensor with an inexpensive structure even when the gear box mounting surface and the control unit are opposed to each other. It is an object.

In order to achieve the above object, an electric power steering apparatus according to claim 1 of the present invention is an electric motor that transmits a steering assist force to a steering shaft to which a steering torque is transmitted via a reduction mechanism in a reduction gear box. And a control unit including a control board on which a control circuit for driving and controlling the electric motor is mounted, and a cover for housing the control board of the control unit on a gear box mounting surface formed on the outer periphery of the reduction gear box And mounting the control unit with the cover plate portion close to each other, and projecting a plurality of external connection terminals connected to the torque sensor built in the reduction gear box from the opening formed in the gear box mounting surface, Each of the plurality of external connection terminals is passed through a notch formed in the cover plate and provided on the control board. In the electric power steering apparatus that is electrically connected directly to a plurality of board side terminals, a gear box side inclined surface is formed on the periphery of the opening of the gear box mounting surface, and the cover plate portion of the control unit A cover step portion that bulges outward is formed, the notch portion is formed at the tip of the cover step portion, and the cover plate portion is brought close to the gear box mounting surface for mounting the control unit. In this case, the outer periphery of the cover step portion is formed as a cover-side inclined surface that is in surface contact with the gear box-side inclined surface while surrounding the opening, and the gear box mounting surface faces downward. When a reduction gearbox is placed and the control unit is mounted below the gearbox mounting surface, the gearbox side inclined surface and the cover side inclined surface Face, extends with a inclined upward toward the plurality of external connection terminals passing through the opening and the notch.
According to the first aspect of the present invention, when the reduction gear box is arranged so that the gear box mounting surface faces downward, and the control unit is mounted below the gear box mounting surface, the gear box side inclined surface and the cover side inclined surface are arranged. Since the surface extends with an upward slope toward the plurality of external connection terminals passing through the opening and the notch, water droplets adhering to the gearbox mounting surface flow into the opening. Can be prevented.

According to a second aspect of the present invention, in the electric power steering apparatus according to the first aspect, the gear box side inclined surface is a chamfered portion formed on a peripheral edge of the opening, and the cover side inclined surface is It is formed with a flat surface in surface contact with the chamfered portion.
According to the first and second aspects of the present invention, intrusion of conductive foreign matter generated on the outer peripheral side of the reduction gear box is blocked. Further, it is possible to prevent a large foreign object (for example, a screw, a pebble, etc.) from entering the opening side.

According to a third aspect of the present invention, in the electric power steering apparatus according to the first or second aspect, a plate-shaped sealing member or packing is interposed between the gear box side inclined surface and the cover side inclined surface. Has been.
According to the present invention, the sealing performance against moisture can be improved, and further the invasion of conductive foreign matters can be prevented.

  According to the electric power steering apparatus of the present invention, when the cover plate portion is brought close to the gear box mounting surface for mounting the control unit, the gear box side inclined surface formed around the opening portion, the control unit Since the cover-side inclined surface formed on the cover plate portion is in surface contact with the opening while surrounding the opening, it is possible to reliably prevent intrusion of conductive foreign matters or large foreign matters with an inexpensive structure.

It is the perspective view shown from the right direction at the time of applying one Embodiment of the electric power steering device which concerns on this invention to a right-hand drive vehicle. It is a longitudinal cross-sectional view which shows the principal part of the reduction gear box which comprises an electric power steering apparatus. It is the perspective view which showed the reduction gear box before mounting | wearing with a control unit from the vehicle width direction. FIG. 4 is a cross-sectional view taken along line AA in FIG. 3. FIG. 4 is a cross-sectional view taken along line B-B in FIG. 3. It is a disassembled perspective view of a control unit. It is CC sectional view taken on the line of FIG. It is DD sectional view taken on the line in FIG. It is the schematic which showed the contact state of the cover board part and gearbox mounting surface of 1st Embodiment which concerns on this invention from the vehicle rear. It is the schematic which showed the contact state of the cover board part and gearbox attachment surface of 1st Embodiment which concerns on this invention from the vehicle width direction. It is the schematic which showed the contact state of the cover board part and gearbox attachment surface at the time of mounting | wearing a lower part of the gearbox attachment surface of 1st Embodiment which concerns on this invention from a vehicle rear. It is the schematic which showed the contact state of the cover board part and gearbox attachment surface at the time of mounting | wearing a lower part of the gearbox attachment surface of 1st Embodiment which concerns on this invention from the vehicle width direction. It is a figure which shows the shape of the sealing member used by 2nd Embodiment which concerns on this invention. It is the schematic which showed the state which contact | abutted the cover board part and the gear box attachment surface via the sealing member in 2nd Embodiment which concerns on this invention from the vehicle rear. It is the schematic which showed the state which contact | abutted the cover board part and the gear box attachment surface via the sealing member in 2nd Embodiment which concerns on this invention from the vehicle width direction.

Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing an electric power steering apparatus according to the present invention from the front of a vehicle.
Reference numeral 1 in FIG. 1 denotes a column-type electric power steering device. A reduction gear box 4 is connected to a steering column 3 that rotatably houses a steering shaft 2 connected to a steering wheel (not shown). The reduction gear box 4 is provided with an electric motor 5 whose axial direction is extended in a direction perpendicular to the axial direction of the steering column 3.

The steering column 3 has a double tube structure of an inner tube 3a and an outer tube 3b. The inner tube 3 a and the reduction gear box 4 of the steering column 3 are attached to the vehicle body side by an upper mounting bracket 6 and a lower mounting bracket 7.
The lower mounting bracket 7 is formed of a mounting plate portion 7a attached to the vehicle body side member, and a pair of support plate portions 7b extending in parallel from the lower surface of the mounting plate portion 7a in the left-right direction with a predetermined interval. . And the lower end of the support plate part 7b is rotatably connected to the support part 4b integrally formed in the vehicle body front side of the reduction gear box 4 via the pivot 7c.

  The upper mounting bracket 6 is formed on a pair of flanges 6a, a pair of support plate portions 6c fixed to the lower ends of the flanges 6a and spaced apart in the left-right (vehicle width) direction, and the pair of support plate portions 6c. And a tilt mechanism 6 d that supports the outer tube 3 b of the steering column 3. A slit 6a1 is formed in the flange 6a, and a release capsule 6b is fitted in the slit 6a1. A bolt through hole 6b1 is formed in the release capsule 6b, and a fixing bolt (not shown) that penetrates the bolt through hole 6b1 from below the release capsule 6b is screwed into a vehicle body side member (not shown). The flange 6a is attached to the vehicle body side member.

Then, by tilting the tilt lever 6g of the tilt mechanism 6d and releasing the support state of the outer tube 3b, the tilt position of the steering column 3 can be adjusted up and down around the pivot 7c of the lower mounting bracket 7. .
As shown in FIG. 2, the steering shaft 2 has an input shaft 2a whose upper end is connected to the steering wheel, and an output shaft 2c that covers the torsion bar 2b connected to the lower end of the input shaft 2a via the torsion bar 2b. It consists of

  The reduction gear box 4 is formed by die-casting, for example, any one of materials having high thermal conductivity, such as aluminum, aluminum alloy, magnesium, and magnesium alloy. As shown in FIG. 2, the reduction gear box 4 includes a worm storage portion 12 that stores a worm 11 connected to an output shaft (not shown) of the electric motor 5, and a central shaft below the worm storage portion 12. A worm wheel storage portion 14 for storing a worm wheel 13 having a central axis perpendicular to the worm 11 and meshing with the worm 11, and a torque sensor 15 integrally and coaxially connected to the rear side of the vehicle body of the worm wheel storage portion 14 are stored. A torque sensor housing portion 16, a motor mounting portion 17 for mounting the electric motor 5 formed on the open end surface of the worm housing portion 12, and a cylindrical column mounting portion 18 formed at the rear end of the vehicle body of the torque sensor housing portion 16. And a control unit mounting portion 20 for mounting a control unit 19 formed over part of the worm storage portion 12 and the worm wheel storage portion 14. It is equipped with a. The front end portion of the vehicle body of the steering column 3 is externally fitted and connected to the column mounting portion 18 of the reduction gear box 4.

  Here, as shown in FIG. 2, the torque sensor 15 magnetically detects the twisted state between the input shaft 2a and the output shaft 2c of the steering shaft 2 and detects a pair of steering torques transmitted to the steering shaft 2. The external connection terminals 15c are configured to be detected by the coils 15a and 15b and project outwardly in parallel to the direction perpendicular to the central axis of the steering column 3 at the start and end of winding of the pair of detection coils 15a and 15b, respectively. 15d and 15e, 15f are connected, and the protruding portions of these external connection terminals 15c to 15f are bent in parallel with the central axis of the steering column 3 at the central portion to form an L shape.

  As shown in FIG. 1, the electric motor 5 has a connection terminal (not shown) at a position close to and facing the control unit 19 mounted on the control unit mounting portion 20 at a position close to the mounting flange 5b. Although not specifically shown, each of the connection terminals is insulated from each other in a synthetic resin brush support body having an armature insertion hole at the bottom center, and is individually connected to two sets of brushes. The arc-shaped connection terminals are integrally formed at opposite ends.

As shown in FIG. 3, the control unit mounting portion 20 formed in the reduction gear box 4 includes a flat mounting surface 20a formed by the worm storage portion 12 and the upper side of the worm wheel storage portion 14 below, and torque. A unit mounting surface 20b formed on the upper surface of the sensor storage portion 16 and orthogonal to the flat mounting surface 20a is formed in an L shape when viewed from the left-right direction.
An opening 20d that communicates with the internal space of the torque sensor storage unit 16 that stores the torque sensor 15 is formed at the center of the unit mounting surface 20b of the control unit mounting unit 20 in the left-right direction. The external connection terminals 15c to 15f of the torque sensor 15 are provided so as to protrude above the unit mounting surface 20b through 20d.

Further, a frame mounting surface 20c having a narrow width is formed on the vehicle rear end surface of the motor mounting portion 17 at a position parallel to the flat mounting surface 20a and on the vehicle rear side from the flat mounting surface 20a.
Here, as shown in FIG. 4, the unit mounting surface 20b of the control unit mounting portion 20 includes a first unit mounting surface 20b1 and a second unit mounting surface that surround the opening 20d and are positioned in the left-right direction (vehicle width direction). 20b2 and a third unit mounting surface 20b3 formed continuously from the first and second unit mounting surfaces 20b1 and 20b2 at a position spaced from the flat mounting surface 20a, as shown in FIG. A chamfered portion 33 extending in a planar shape at a predetermined inclination angle is formed on the edge of the first to third unit mounting surfaces 20b1 to 20b3 on the opening 20d side. As described above, the chamfered portion 33 is formed at the edge of the unit mounting surface 20b surrounding the opening 20a in two edges in the vehicle width direction and in one direction on the vehicle rear side.

On the other hand, as shown in FIG. 6, the control unit 19 mounted on the control unit mounting section 20 includes a heat radiating plate 21, a power board 22, a rectangular frame 23, a control board 24, and a cover 26. I have.
The heat radiating plate 21 is directly fixed to the flat mounting surface 20a of the control unit mounting portion 20 via heat radiating grease. The power substrate 22 is an integrated circuit 22a, 22b such as an H bridge circuit composed of a power switching element such as a field effect transistor that drives and controls the electric motor 5, and a pulse width modulation circuit that drives the power switching element of the H bridge circuit. Is implemented.

  The control board 24 is attached to the front surface of the frame 23, and has through holes 24a to 24d that are directly inserted through the external connection terminals 15c to 15f of the torque sensor 15. A torque detection value from the torque sensor 15 or a vehicle speed sensor (not shown) is provided. The steering assist current command value is calculated based on the detected vehicle speed value from the vehicle, and the current feedback control is performed based on the steering assist current command value and the detected value of the motor current output to the electric motor 5 to perform the pulse of the power board 22. In addition to the micro control unit (MCU) that controls the steering assist force generated by the electric motor 5 and its peripheral devices by calculating the voltage command value to the width modulation circuit, discrete components 24e such as capacitors, coils, relays, etc. Is implemented.

  The frame 23 is a member that surrounds the power board 22, and includes a rectangular frame-shaped frame body 23 a and a mounting plate portion 23 b that is formed at the left end of the frame body 23 a and is fixed to the frame mounting surface of the reduction gear box 4. A terminal block 23c fixed on the mounting plate 23b and electrically connected to a connection terminal of the electric motor 5 and a female connector 45 fixed to the right end of the frame body 23a are provided. Although not shown, the female connector 45 includes a power connector 45a that is connected to a battery via a male connector for power supply, and a signal connector 45b that is connected to a network such as a CAN that transmits and receives data to / from a control device in each part of the vehicle body. And. The power board 22 and the control board 24 are connected via a connection terminal 22c.

The cover 26 is a metal member capable of blocking electromagnetic waves and protecting internal components. As shown in FIG. 6, the cover 26 has a rectangular first plate portion 27 that covers the control board 24 and the first plate portion 27. Second and third plate portions 28 and 29 extending orthogonally from the edge in the longitudinal direction, and second and third plate portions 28 and 29 from the edge in the short direction of the first plate portion 27 The fourth and fifth plate portions 30 and 31 extending in the same direction and the second plate portion 28 and the fourth and fifth plate portions 30 and 31 are formed in a direction orthogonal to the outside of the cover. And a plurality of fixing pieces 32 having screw insertion holes. Further, the fourth plate portion 30 is formed with a notch 30 a surrounding the outer periphery of the female connector 45.
At the center in the longitudinal direction of the second plate portion 28, a notch portion 28a notched in a gate shape is formed.

7 and 8 show in detail the peripheral shape of the notch 28a described above, and a step 34 protruding outward from the cover 26 is formed at the periphery of the notch 28a.
That is, as shown in FIG. 7, the stepped portion 34 that protrudes outward from both sides in the longitudinal direction of the second plate portion 28 includes inclined plate portions 35 a and 36 a that protrude outward with a predetermined inclination angle, It comprises end plate portions 35b and 36b that extend in parallel with the second plate portion 28 from the tip ends of the inclined plate portions 35a and 36a and form a notch portion 28a.
Further, as shown in FIG. 8, the stepped portion 34 protruding outward from the first plate portion 27 side includes an inclined plate portion 37a protruding outward with a predetermined inclination angle, and a tip of the inclined plate portion 37a. And an end plate portion 37b extending in parallel with the second plate portion 28 to form a notch portion 28a.

Then, the heat radiation plate 21 and the frame 23 of the control unit 19 are fixed to the control unit mounting portion 20 of the reduction gear box 4, and the external connection of the torque sensor 15 protruding from the opening 20 d of the control unit mounting portion 20 of the reduction gear box 4. After the terminals 15c to 15f (see FIG. 3) are directly inserted and soldered into the through holes 24a to 24d (see FIG. 6) of the control board 24 of the control unit 19, the cover 26 is also fixed to the control unit mounting portion 20. Thus, the control unit 19 is mounted on the control unit mounting portion 20 of the reduction gear box 4. Further, the terminal block 23 c fixed to the mounting plate portion 23 b of the frame 23 and the connection terminal of the electric motor 5 are electrically connected. The electrically connected terminal block 23c and the connection terminal of the electric motor 5 are covered with a synthetic resin terminal cover denoted by reference numeral 27 in FIG.
The gearbox mounting surface of the present invention corresponds to the unit mounting surface 20b, the cover plate portion of the present invention corresponds to the second plate portion 28, the gearbox side inclined surface of the present invention corresponds to the chamfered portion 33, The cover step portion of the present invention corresponds to the step portion 34, and the cover side inclined surface of the present invention corresponds to the inclined plate portions 35a, 36a, and 37a.

Next, the operation of the above embodiment will be described.
When power is supplied from the battery to the power board 22 and the control board 24 by turning on an ignition switch (not shown) of the vehicle body, a steering assist control process is executed by the micro control unit (MCU), and the torque sensor 15 and the vehicle speed sensor (not shown) are A steering assist current command value is calculated based on the detected value. A current feedback process is executed based on the steering assist current command value and the motor current detected by the motor current detection unit to calculate a voltage command value. By supplying this voltage command value to the gate drive circuit of the power board 22 and controlling the H bridge circuit, a motor drive current flows through the electric motor 5 and the electric motor 5 needs to be operated in the forward or reverse direction. Drive to generate force.
Therefore, a steering assist force corresponding to the steering torque of the steering wheel is generated from the electric motor 5, and this steering assist force is transmitted to the output of the steering shaft 2 via the worm 11 and the worm wheel 13, whereby the steering wheel Can be steered with a light steering force.

  Here, according to the present embodiment, when the second plate portion 28 of the cover 26 faces the unit mounting surface 20b in order to mount the control unit 19 on the control unit mounting portion 20 of the reduction gear box 4, as shown in FIG. The first and second unit mounting surfaces in which the inclined plate portions 35a and 36a of the step portion 34 formed on the periphery of the notch 28a of the cover 26 (second plate portion 28) of the control unit 19 surround the opening portion 20d. As shown in FIG. 10, the inclined plate portion of the stepped portion 34 formed on the peripheral edge of the notch 28a of the cover 26 (on the first plate portion 27 side) is brought into surface contact with the chamfered portion 33 formed on the edges of 20b1 and 20b2. 37a is in surface contact with the chamfered portion 33 formed at the edge of the third unit mounting surface 20b3.

The external connection terminals 15c to 15f of the torque sensor 15 pass through the opening 20d, and the conductive foreign matter generated on the outer peripheral side of the reduction gear box 4 is on the opening 20d side where the external connection terminals 15c to 15f are arranged. Even if it tries to enter, the inclined plate portions 35a, 36a, and 37a of the step portion 34 of the cover 26 are in close contact with the chamfered portion 33 at the periphery of the opening 20d by surface contact, so that the intrusion is blocked.
Accordingly, the conductive foreign matter does not contact any pair of the plurality of external connection terminals 15 c to 15 f of the torque sensor 15, and the torque sensor 15 outputs a normal torque detection value to normalize the electric motor 5. Drive control can be performed.

Further, the inclined plate portions 35a, 36a, and 37a of the stepped portion 34 of the cover 26 are brought into close contact with the chamfered portion 33 at the periphery of the opening 20d by surface contact, so that a large foreign object (for example, a screw, a pebble, etc.) is opened to the opening 20d. It is possible to prevent trying to enter the side.
Further, the inclined plate portions 35a, 36a, 37a of the step portion 34 of the cover 26 of the control unit 19 are arranged in three directions (in the vehicle width direction) on the chamfered portion 33 of the unit mounting surface 20b surrounding the opening 20a of the control unit mounting portion 20. 2 and one direction on the rear side of the vehicle), it is possible to prevent the displacement of the cover 26 with respect to the control unit mounting portion 20 of the reduction gear box 4 and to easily assemble the control unit 19. Can be done.

  Here, in the above embodiment, the electric power steering apparatus in which the control unit 19 is mounted on the upper part of the control unit mounting portion 20 of the reduction gear box 4 has been described, but the reduction gear box 4 so that the control unit mounting portion 20 faces downward. And a structure in which the control unit 19 is mounted below the control unit mounting portion 20, as shown in FIGS. 11 and 12, water droplets attached to the unit mounting surface 20b will flow toward the opening 20d. Even so, the inclined plate portions 35a, 36a, 37a of the cover 26 and the chamfered portion 33 of the unit mounting surface 20b are inclined upward toward the external connection terminals 15c to 15f passing through the opening 20d and the cutout portion 28a. Since the contact is made, the water droplets can be prevented from flowing into the opening 20d.

Here, FIG. 13 to FIG. 15 show other embodiments according to the present invention.
In the present embodiment, a seal member 38 is interposed between the stepped portion 34 of the cover 26 of the control unit 19 and the periphery of the opening 20d.
The seal member 38 is formed of an elastic material such as a flexible foamed resin material or synthetic rubber. As shown in FIG. 13, a plate-like seal body 38a formed in a U shape in plan view, and a seal body It is comprised with the plate-shaped seal part 38b formed by inclining in the same direction of the thickness direction from the inner side of 38a.

  Then, as shown in FIG. 14, the seal body 38a is brought into contact with the first and second unit mounting surfaces 20b1 and 20b2 formed so as to surround the opening 20d, and the edges of the first and second unit mounting surfaces 20b1 and 20b2 As shown in FIG. 15, the seal body 38a is brought into contact with the third unit mounting surface 20b3 and the chamfered portion is formed at the edge of the third unit mounting surface 20b3. The sealing member 38 is disposed by abutting the seal portion 38 b on the contact member 33, and the inclined plate portions 35 a, 36 a, 37 a of the step portion 34 of the cover 26 are brought into contact with the seal member 38, thereby opening the step portion 34 of the cover 26 and the opening portion. A seal member 36 is interposed between the periphery of the portion 20d.

According to the present embodiment, the sealing performance can be improved by interposing the sealing member 38 between the inclined plate portions 35a, 36a, 37a of the step portion 34 of the cover 26 and the chamfered portion 33 at the periphery of the opening 20d. At the same time, the intrusion of conductive foreign matter generated on the outer peripheral side of the reduction gear box 4 can be blocked and large foreign matter can be prevented from entering the opening 20d side.
Further, the reduction gear box 4 is arranged so that the control unit mounting portion 20 faces downward, and the control unit 19 is mounted at the lower part of the control unit mounting portion 20, and water droplets attached to the unit mounting surface 20b are opened to the opening portion 20d. Even if it is going to flow toward the external connection terminals 15c to 15f, the inclined plate portions 35a, 36a, 37a of the cover 26 and the chamfered portion 33 of the unit mounting surface 20b pass through the opening 20d and the cutout portion 28a. As a result, the water droplets can be reliably prevented from flowing into the opening 20d.

In this embodiment, the seal member 38 is interposed between the step portion 34 of the cover 26 of the control unit 19 and the periphery of the opening 20d. However, the same effect can be obtained even if a sheet-like packing material is interposed. Can be played. The same effect can be obtained even if an oily gel such as a liquid curable sealing material or grease is interposed between the step 34 of the cover 26 of the control unit 19 and the periphery of the opening 20d.
In the above-described embodiment, the case where the electric motor 5, the control unit 19, and the female connector 45 are arranged in a straight line along a line orthogonal to the central axis of the steering column 3 has been described. It may be arranged in a straight line along a line intersecting the central axis of the steering column 3.

  Moreover, in the said embodiment, although the case where a brush motor was applied as the electric motor 5 was demonstrated, it is not limited to this, You may make it apply a brushless motor, In this case, a connection terminal 5c and 5d are connected to the power supply side of the excitation coil of each phase, and, for example, an inverter circuit having a field effect transistor (FET) for driving a brushless motor on the power board 23 and a gate of the field effect transistor of the inverter circuit are pulse width modulated. A gate driving circuit driven by a signal may be mounted.

  Furthermore, in the above-described embodiment, the case where the present invention is applied to a right-hand drive vehicle has been described. However, the present invention is not limited to this, and when applied to a left-hand drive vehicle, the reduction gear box 4 and the electric motor 5 The control unit 19 is arranged symmetrically with respect to the vertical plane passing through the central axis of the steering column 3, that is, the electric motor 5 is arranged on the right side of the control unit 19, and the female connector 45 and the terminal block 24c of the control unit 19 are connected. What is necessary is just to arrange | position on the left side, Furthermore, you may make it arrange | position the electric motor 5 on the vehicle outer side, and arrange | position the female connector 45 and the terminal block 24c on the vehicle inner side.

DESCRIPTION OF SYMBOLS 1 ... Electric power steering device, 2a ... Input shaft, 2b ... Torsion bar, 2c ... Output shaft, 3 ... Steering column, 3a ... Inner tube, 3b ... Outer tube, 4 ... Reduction gear box, 4b ... Support part, 5 ... Electric motor, 5b ... flange, 6 ... upper mounting bracket, 6a ... flange, 6a1 ... slit, 6b ... release capsule, 6b1 ... bolt through-hole, 6c ... support plate, 6d ... tilt mechanism, 6g ... tilt lever, 7 DESCRIPTION OF SYMBOLS ... Lower mounting bracket, 7a ... Mounting plate part, 7b ... Supporting plate part, 7c ... Pivot, 11 ... Worm, 12 ... Worm storage part, 13 ... Worm wheel, 14 ... Worm wheel storage part, 15 ... Torque sensor, 15a, 15b ... Detection coil, 15c-15f ... External connection terminal, 16 ... Torque sensor housing, 17 ... Motor mounting, 18 ... Column mounting , 19 ... control unit, 20 ... control unit mounting portion, 20a ... flat mounting surface, 20b ... unit mounting surface (gearbox mounting surface), 20b1 ... first unit mounting surface, 20b2 ... second unit mounting surface, 20b3 ... first 3 unit mounting surface, 20c ... frame mounting surface, 20d ... opening, 21 ... heat dissipation plate, 22 ... power substrate, 22a, 22b ... integrated circuit, 22c ... connection terminal, 23 ... frame, 23a ... frame body, 23b ... installation Plate part, 23c ... Terminal block, 24 ... Control board, 24a-24d ... Through hole, 24e ... Discrete parts, 26 ... Cover, 27 ... First plate part, 28 ... Second plate part (cover plate part), 28a ... Notch, 29 ... third plate, 28a ... notch, 30 ... fourth plate, 31 ... fifth plate, 32 ... fixed piece, 33 ... chamfer, 34 ... step 35a, 36a, 37a ... inclined plate part, 35b, 36b, 37b ... end plate part, 38 ... seal member, 38a ... seal body, 38b ... seal part, 45 ... female connector, 45a ... power connector, 45b ... signal connector

Claims (3)

An electric motor for transmitting a steering assist force to a steering shaft to which a steering torque is transmitted via a speed reduction mechanism in a speed reduction gear box, and a control unit including a control board on which a control circuit for driving and controlling the electric motor is mounted The control unit is mounted on the gear box mounting surface formed on the outer periphery of the reduction gear box with the cover plate portion of the cover for housing the control board close thereto, and the control unit is mounted in the reduction gear box. Projecting a plurality of external connection terminals connected to the torque sensor from an opening formed in the gearbox mounting surface, and passing each of the plurality of external connection terminals through a notch formed in the cover plate part, In the electric power steering apparatus that is electrically connected directly to a plurality of board side terminals provided on the control board,
Forming a gear box side inclined surface at the periphery of the opening of the gear box mounting surface;
Forming a cover stepped portion that bulges outward from the cover plate portion of the control unit, forming the notch at the tip of the cover stepped portion,
When the cover plate portion is brought close to the gear box mounting surface for mounting the control unit, the outer periphery of the cover step portion is in contact with the gear box-side inclined surface while surrounding the opening. While being formed as a side inclined surface ,
When the speed reduction gear box is arranged so that the gear box mounting surface faces downward, and the control unit is mounted on the lower part of the gear box mounting surface, the gear box side inclined surface and the cover side inclined surface are An electric power steering device, wherein the electric power steering device extends upwardly toward the plurality of external connection terminals passing through the opening and the notch .   The gear box side inclined surface is a chamfered portion formed at a peripheral edge of the opening, and the cover side inclined surface is formed by a flat surface in surface contact with the chamfered portion. The electric power steering apparatus according to 1. 3. The electric power steering apparatus according to claim 1, wherein a plate-like seal member or packing is interposed between the gear box side inclined surface and the cover side inclined surface .

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