JP4794286B2 - Electric power steering device - Google Patents

Description

  The present invention relates to an electric power steering apparatus including a steering transmission mechanism of a rack and pinion type for a vehicle.

Patent Document 1 discloses an electric power steering apparatus having a rack and pinion type steering transmission mechanism and having a structure in which a control board for driving and controlling a motor is accommodated in a controller case provided in the rack case. ing.
JP 11-171028 A (paragraph [0020])

  In Patent Document 1, a motor is projected from a rack case, and a lead wire extends from the motor to a hole formed in a side surface of the controller case, and extends from a control board in the controller case to the hole. It is connected to the plate-like part of the bus bar that faces.

Although the connection method between the plate-like portion of the bus bar and the lead wire is not disclosed, it is usually connected by soldering, welding or screwing.
Therefore, the assembly work efficiency is poor.

  The present invention has been made in view of the above points, and the object of the present invention is to provide an electric power steering device having a housing for housing a motor control board in a rack case and having excellent assembly work efficiency. It is in.

In order to achieve the above object, according to the first aspect of the present invention, the steering wheel is steered by the sliding of the rack shaft (3) engaged with the steering pinion (9) connected to the steering side, and the steering side In the electric power steering apparatus in which the power of the motor (10) that is driven and controlled according to the steering torque of the rack is transmitted to the sliding of the rack shaft (3) to assist the steering, the rack shaft (3) is slidable The motor (10) is housed in a part of the motor case (2a) of the rack case (2) housed in the housing, and a housing in which a control board for driving and controlling the motor is housed is adjacent to the rack case. It was formed, when the motor (10) is accommodated in the motor case (2a), projecting to the conductive plate piece extending from the motor (10) (16a) of the housing (2b), wherein A bar-like shape protruding vertically near the tip of the conductive plate piece (16a) Motor side connection terminal (16) is positioned toward the opening (20) of the housing (2b) at a predetermined position, wherein the control board (40) side a cylindrical shape corresponding to the motor-side connecting terminals (16) A board-side connection terminal (46) formed is fixed with one opening directed in the insertion direction to the housing (2b), and the cylindrical board-side connection terminal (46) to the housing (2b). A trumpet-shaped guide member (46b) that is continuous with the opening facing the insertion direction is provided, and the control board (40) faces the bottom surface (22) from the opening (20) of the housing (2b). When inserted into the housing (2b), at the same time, the rod-shaped motor side connection terminal (16) is guided by the guide member (46b) on the control board (40) side, and the cylindrical board side connection terminal (46 ) To be electrically connected by contacting each other.

  According to a second aspect of the present invention, in the electric power steering apparatus according to the first aspect, the guide member (46b) is configured such that the cylindrical board side connection terminal (46) extends. Features.

  According to a third aspect of the present invention, in the electric power steering apparatus according to the first or second aspect, the motor side connection terminal (16) has a round bar shape, and the board side connection terminal (46) has a cylindrical shape. The guide member (46b) has a conical shape.

  According to the electric power steering apparatus of the first aspect, the control board is inserted into the housing formed in the rack case or the steering gear box, and at the same time, the rod-shaped motor side connection terminal is opened to the trumpet-shaped guide member. Since they are guided and inserted into the cylindrical board side connection terminals and contacted with each other to be electrically connected, it is possible to connect them securely without any need for welding or the like, and the assembly work efficiency is extremely good.

  According to the electric power steering apparatus of the second aspect, since the guide member is configured by extending the cylindrical board side connection terminal, it is easy to manufacture the guide part at the same time by manufacturing the board side connection terminal. In addition, it is easy to attach to the control board, and the cost can be reduced.

  According to the electric power steering apparatus of the third aspect, the motor side connection terminal has a round bar shape, the board side connection terminal has a cylindrical shape, and the guide member has a conical shape. Terminals and guide members can be easily manufactured.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
An overall front view of an electric power steering apparatus 1 according to the present embodiment is shown in FIG. 1, a top view is shown in FIG. 2, and a front view showing the internal structure is shown in FIG.

  The electric power steering apparatus 1 includes a rack shaft 3 that slides in a left-right axial direction within a substantially cylindrical rack case 2 oriented in the left-right direction of the vehicle (the left and right sides are reversed in FIGS. 1, 2, and 3). It is housed freely.

  The tie rods 5 and 5 are moved to the both ends of the rack shaft 3 protruding from the opening on both ends of the rack case 2 via joints 4 and 4, respectively, and the steered wheels of the vehicle are steered via a steering mechanism.

A steering gear box 6 is provided near the right end (left end in FIGS. 1 to 3) of the rack case 2.
In the steering gear box 6, an input shaft 7 connected via a joint to a steering shaft integrally mounted with a steering wheel (not shown) is rotatably supported via a bearing. The shaft 7 is connected to the steering pinion shaft 9 via a torsion bar 8 in the steering gear box 6 so as to be relatively twistable.

The helical teeth 9a of the steering pinion shaft 9 mesh with the rack teeth 3a of the rack shaft 3 to constitute a rack and pinion mechanism.
Therefore, the steering force transmitted to the input shaft 7 by the turning operation of the steering wheel rotates the steering pinion shaft 9 via the torsion bar 8, and meshes the helical teeth 9a of the steering pinion shaft 9 and the rack teeth 3a. Thus, the rack shaft 3 is slid in the left-right axis direction.

On the other hand, the central part where the diameter of the rack case 2 is expanded serves as a motor case 2a in which the motor 10 is accommodated.
The motor 10 is provided with an annular inner rotor 11 rotating on the outer periphery of the rack shaft 3 in which the ball screw 3b is engraved, and an outer stator 12 is provided on the outer peripheral surface of the motor case 2a.

  A connection nut 13 press-fitted into the inner peripheral surface of the annular inner rotor 11 extends leftward (rightward in FIG. 3), and is a ball nut member rotatably supported on the inner periphery of the motor case 2a via a bearing 15 Combined with 14 in one piece.

The ball nut member 14 is screwed to the ball screw 3b of the rack shaft 3 via a ball.
Therefore, when the motor 10 is driven and the inner rotor 11 rotates, the ball nut member 14 integrally rotates, and the rack shaft 3 screwed with the ball nut member 14 via the ball slides to the left and right to assist the steering force. be able to.

  A housing 2 b that houses a control board that drives and controls the motor 10 is formed in front of the rack shaft 3 in a portion between the motor case 2 a of the rack case 2 and the steering gear box 6.

  The housing 2b has a front opening 20 that is substantially horizontally elongated toward the front, and a peripheral surface is formed with a mating surface 21 for attaching a front cover 30 that closes the opening 20 in a rectangular frame shape. A groove 21a into which the member 32 is fitted is formed, and screw holes 21b are provided at the outer four corners of the groove 21a (see FIG. 8).

  The bottom surface 22 facing the opening 20 of the housing 2b has a shallow center height position where the rack shaft 3 runs in the left-right direction behind it, and has a deep top and bottom, and the upper left corner of the bottom surface 22 (right in FIG. 8). Has a particularly deep recess 23.

On the bottom surface 22 of the housing 2b, mounting bosses 24 are formed so as to protrude from predetermined four places shown in FIG.
In order to attach the control board 40, the four attachment bosses 24 are formed on the same front surface, and are respectively formed with screw holes 24a.

4 to 7, the front cover 30 that closes the opening 20 is a press-molded product such as an aluminum die-casting or a stainless steel plate, and the inside of the rectangular peripheral edge portion 30a facing the mating surface 21 bulges slightly outward. The flat plate portion 30b has protrusions 31 bulged by a predetermined length toward the inner mounting boss 24 at respective positions facing the four mounting bosses 24 protruding from the bottom surface 22 of the housing 2b. Is formed.
Note that mounting holes 30c are formed in the four corners of the rectangular peripheral edge portion 30a of the front cover 30 corresponding to the screw holes 21b.

  As shown in FIG. 7, a seal member 32, which is a rubber ring, is fitted into the groove 21a of the mating surface 21 of the housing 2b, the front cover 30 is put on the front opening 20 of the housing 2b, and the rectangular peripheral edge 30a is aligned with the mating surface 21. Then, the screw 33 is passed through the mounting hole 30c and screwed into the screw hole 21b, thereby fixing the front cover 30 and closing the front opening 20 of the housing 2b in a liquid-tight manner.

The housing 2b has a peeping opening 25 formed in the upper side wall so that the inside of the housing 2b can be seen from above.
The peripheral edge of the peep opening 25 is formed with a mating surface 26 for attaching an upper surface cover 35 that closes the peep opening 25, and the mating surface 26 is formed with a groove 26a into which the seal member 38 is fitted, in a rectangular frame shape. Screw holes 26b are provided at two locations on the left and right sides of the groove 26a.

  Referring to FIG. 7, the upper surface cover 35 for closing the peeping opening 25 is made of press such as aluminum die-casting or stainless steel plate, and the center of the rectangular flat plate portion 35a corresponding to the substantially rectangular mating surface 26 is slightly outward. The bulge has a bulge portion 35b, and a connector 36 is formed on the right side of the bulge portion 35b.

Then, two pairs of left and right clamping pieces 37, 37 are formed so as to protrude side by side from a predetermined position on the left side of the back surface of the top cover 35.
The pair of sandwiching pieces 37, 37 can sandwich the cylindrical portion of the capacitor 44 projecting from a cylindrical control board 40, which will be described later, by sandwiching it from the left and right.
Attachment holes 35c are formed on the left and right sides of the rectangular flat plate portion 35a of the upper surface cover 35 corresponding to the screw holes 26b.
Note that the upper surface cover 35 can be integrally formed of an insulating resin.

  As shown in FIG. 7, a seal member 38, which is a rubber ring, is fitted into the groove 26a of the mating surface 26 of the upper side wall of the housing 2b, the top cover 35 is put on the peeping opening 25 of the housing 2b, and the rectangular flat plate portion 35a is aligned. By screwing the screw 39 into the mounting hole 35c in accordance with the surface 26 and screwing it into the screw hole 26b, the upper surface cover 35 can be fixed and the peeping opening 25 of the housing 2b can be liquid-tightly closed.

As shown in FIGS. 6 and 8, a pair of conductive plate pieces 16a, 16a of power lines for supplying power to the motor 10 from the left motor case 2a side protrudes in the housing 2b.
Round bar-like motor-side connection terminals 16 and 16 are provided projecting (upward) toward the opening of the housing 2b near the tips of the conductive plate pieces 16a and 16a.

  The control board 40 accommodated in the housing 2b has a substantially rectangular shape that is slightly smaller than the front opening 20 of the housing 2b, and various functional elements are arranged on the front and back of the printed wiring board. .

  As shown in FIGS. 10 to 12, the main functional elements to be mounted include a CPU 41 mounted on the front surface of the control board 40 in a substantially central position, and the back surface is divided into front and rear portions with a central space. Four FETs (field effect transistors) 42 are attached to a support base 43 that is a heat sink on the front side, two capacitors 44 project from the rear side, and a power relay 45a and a file safe relay 45b are provided. .

A connector 49 is fixed along the rear edge of the back surface of the control board 40.
The ends of the signal lines from the torque sensor 60 provided in the steering gear box 6 are combined into a connector without being exposed from the steering gear box 6, and the connector is connected to the connector 49 of the control board 40. .

Two board side connection terminals 46, 46 are arranged in the front left and right side of the control board 40, and the board side connection terminals 46, 46 project from the motor case 2a side toward the opening of the housing 2b. Corresponding to the motor side connection terminals 16 and 16 of the motor power line.
As shown in FIG. 13, the board-side connection terminal 46 includes a cylindrical main body 46a and a guide part 46b having a conical shape that is opened in a trumpet shape from an opening end of the cylindrical main body 46a facing the motor-side connection terminal 16. The inner diameter of the cylindrical main body 46a is equal to the outer diameter of the round rod-shaped motor side connection terminal 16.

  And the control board 40 inserted facing the bottom face 22 from the front opening 20 of the housing 2b is provided with attachment holes 47 at positions corresponding to the four attachment bosses 24 protruding from the bottom face 22 of the housing 2b. (See FIG. 10).

Therefore, referring to FIG. 7, the control board 40 is inserted in a predetermined positional relationship with respect to the four mounting bosses 24 inserted from the front opening 20 of the housing 2b so as to face the bottom surface 22 and projecting from the bottom surface 22. The screw 48 is passed through the mounting hole 47 of the control board 40 and screwed into the screw hole 24a of the mounting boss 24.
When the control board 40 is inserted into the housing 2b, the signal line from the torque sensor 60 and the connector 49 are connected in advance.

  When the control board 40 is mounted, when the control board 40 comes into contact with the four mounting bosses 24, the board-side connection terminals of the control board 40 are connected to the motor-side connection terminals 16 and 16 projecting toward the opening of the housing 2b. 46 and 46 are opposed to each other, and the round rod-like motor side connection terminals 16 and 16 are guided by the guide portions 46b and 46b of the board side connection terminals 46 and 46 which are opened in a trumpet shape, and are fitted into the cylindrical main body portions 46a and 46a. As shown in FIG. 14, the contact is maintained and the electrical connection is established.

  In this way, the control board 40 is inserted into the housing 2b formed in the rack case 2 and brought into contact with the mounting boss 24. At the same time, the motor side connection terminal 16 and the board side connection terminal 46 come into contact with each other electrically. Since it is connected, it is not necessary to perform welding or the like, and the assembly work efficiency is extremely good.

  Since the opening on the side where the motor side connection terminal 16 is fitted is a guide part 46b that is opened in a trumpet shape, the board side connection terminal 46 is smoothly guided by the guide part 46b. It is fitted into the cylindrical body 46a, and the assemblability is very good.

After the control board 40 is mounted in the housing 2b, the front cover 30 covers the front opening 20 of the housing 2b and is mounted with the screw 33 via the seal member 32 as described above.
As shown in FIGS. 5 and 6, the front cover 30 may be hit with a certain amount of space between the front cover 30 and the control board 40 so that a stepping stone or the like may hit, and the control board 40 is not affected at that time. Thus, a buffer space S is formed.

  Since the front cover 30 has protrusions 31 bulging inward for a predetermined length at positions facing the four mounting bosses 24 protruding from the bottom surface 22 of the housing 2b. 4, the four protrusions 31 protrude in the buffer space toward the screw 48 to which the control board 40 is fixed, and reach a position close to the head of the screw 48.

  As described above, when the front cover 30 covers the front opening 20 and is attached to the housing 2b, the four protrusions 31 of the front cover 30 are positioned close to the four screws 48 fixing the control board 40, respectively. Even if the screw 48 that fixes the control board 40 may be loosened, it will not be loosened any more as soon as it hits the protrusion 31, and an electrical short circuit due to the screw 48 coming off and dropping onto the control board 40 is avoided. be able to.

If the buffer space S is widened so that the control board 40 is not affected by stepping stones, etc., the screw 48 for fixing the control board 40 may fall off, but the protrusion 31 prevents the screw 48 from dropping off as described above. Is done.
The protrusions 31 are formed on the front cover 30. By attaching the front cover 30 to the housing 2b, the protrusions 31 prevent the screws 48 from falling off, so that the number of parts is small and the assembling work is simple.

  The relatively large capacitor 44 mounted on the back surface of the control board 40 is inserted about halfway into a further recessed recess 23 formed above the bottom surface 22 of the housing 2b when the control board 40 is mounted. In order to ensure the performance, by applying an appropriate amount of curable thermal conductive silicone 50 to the half of the capacitor 44 inserted, when the control board 40 is mounted on the mounting boss 24, the curable thermal conductivity The capacitor 44 is integrally fixed to the recess 23 of the housing 2b through the silicone 50 (see FIG. 5).

  Since the capacitor 44 is a relatively large and heavy element, it can be prevented from coming off due to vibration by being integrally fixed to the recess 23 of the housing 2b by the curable thermal conductive silicone 50 as described above. The generated heat can be transmitted to the rack case 2 through the curable heat conductive silicone 50 to be dissipated.

  Whether or not the amount of the curable heat conductive silicone 50 applied to the capacitor 44 is appropriate can be determined by the state when the capacitor 44 is inserted into the recess 23 of the housing 2b. The state in which the capacitor 44 is inserted cannot be seen from the front opening 20 because the control board 40 gets in the way.

  Therefore, the housing 2b of the rack case 2 is provided with a peeping opening 25 on the upper side wall, and as shown in FIG. 15, peeped into a state where the capacitor 44 is inserted into the recess 23 from the peeping opening 25. As can be seen, it is possible to observe whether the amount of the curable thermal conductive silicone 50 applied to the capacitor 44 is appropriate.

  When the application amount of the curable thermal conductive silicone 50 is small, the curable thermal conductive silicone 50 is replenished and applied from the viewing opening 25, and when it is too much, it may be scraped off.

  The peep opening 25 is closed by the top cover 35 as described above, but the top cover 35 is provided with two pairs of clamping pieces 37 on the back surface. The piece 37 sandwiches and holds the base end side halves of the two capacitors 44 having the tip end half inserted into the recess 23 of the housing 2b.

  Since the upper surface cover 35 is fixed to the housing 2b by the screw 39, the capacitor 44 is fixed to the housing 2b, and the capacitor 44 is firmly integrated with the housing 2b together with fixing by the curable thermal conductive silicone 50.

  Therefore, the capacitor 44 is prevented from being detached from the control board 40 due to vibration, and the generated heat can be transferred to the upper surface cover 35 and further to the rack case 2 through the clamping piece 37 to be dissipated, thereby being excellent in vibration resistance and heat dissipation. ing.

  In addition, the top cover 35 is integrally provided with a connector 36 for external power supply and signal input / output, and has the function of a connector as well as the function of holding the capacitor 44, thereby reducing the number of parts, The assembly work can be simplified and the cost can be reduced.

A circuit configuration of the control board 40 accommodated in the housing 2b is shown in FIG. 16 and will be briefly described.
The four FETs 42 constitute a bridge circuit, the plus side of the bridge circuit is connected to the battery 61 as a power source via the power relay 45a, and the minus side is grounded.

The motor 10 is connected via a fail safe relay 45b and a current sensor 55 between a pair of connection lines 54a, 54b connecting the plus side FET 42 and the minus side FET 42.
A capacitor 44 is interposed between the plus side and the minus side of the bridge circuit of the FET 42.

  Each FET 42 is configured to be switching-controlled by the CPU 41, and a signal from the torque sensor 60 and other detection signals are input to the CPU 41.

  By switching control of each FET 42 by the CPU 41, the forward rotation and reverse rotation of the motor 10 can be switched, and even if a large current flows instantaneously due to the capacitor 44 interposed in parallel with the bridge circuit, the FET 42 does not drop in voltage. It is possible to prevent a delay in response of the motor 10 by passing a current.

  When an abnormal current flows through the motor 10, the current sensor 55 detects this and turns off the fail safe relay 45b, and the power relay 45a is turned off for the abnormal current to the control board 40.

Connection from the outside to the control board 40 includes joining the motor side connection terminal 16 and the board side connection terminal 46 for connection to the motor 10, and joining the connector 49 for connection to the torque sensor 60.
The battery 61 and other detection signals are connected via the connector 36 of the top cover 35.

  In the present embodiment, when the control board 40 is mounted in the housing 2b, the cylindrical cylindrical body 46a of the motor side connection terminal 16 of the motor power line and the board side connection terminal 46 on the control board 40 side is connected. However, the motor-side connection terminal may be in the shape of a prism, and the main body of the board-side connection terminal 46 may be in the shape of a rectangular tube.

Further, although a part of the board side connection terminal 46 extends to constitute the guide portion 46b, a trumpet shaped guide member may be constituted by another member. For example, as shown in FIG. The portion facing the motor-side connection terminal of the portion where the board-side connection terminal 75 is fitted is formed to be partially thick, and the guide portion 71 is formed in a conical shape.
The conical surface of the guide portion 71 is continuous with the cylindrical inner surface of the substrate side connection terminal 75.

  Therefore, when the control board 70 is inserted from the housing opening and attached, the round bar-shaped motor side connection terminal is easily guided to the conical guide portion 71 of the control board 70 and becomes the cylindrical board side connection terminal 75. They are inserted and maintained in contact with each other and are electrically connected, so that the assemblability is very good.

  In the above embodiment, the motor is provided in a part of the rack case. However, the present invention can be applied to a case in which the motor is provided in a part of the steering gear box, and the control board. The present invention can also be applied to a housing in which a housing for housing is formed in the steering gear box.

1 is an overall front view of an electric power steering apparatus according to an embodiment of the present invention. It is the same top view. It is the front view which abbreviate | omitted a part which shows the internal structure of this electric power steering device. It is a principal part enlarged front view. It is sectional drawing cut | disconnected by the VV line | wire in FIG. It is sectional drawing cut | disconnected by the VI-VI line in FIG. It is the principal part disassembled perspective view. It is a front view of the housing of a rack case. It is a principal part front view which shows the state which attached the control board in the housing. It is a back view of a control board. It is the same side view. It is the side view seen from another angle. It is a perspective view of a motor side connection terminal and a substrate side connection terminal. It is sectional drawing which shows the state in which the motor side connection terminal and the board | substrate side connection terminal were connected. It is the principal part top view which removed the upper surface cover and looked at the opening for peeping. It is a figure which shows the circuit structure of a control board. It is sectional drawing which shows the board | substrate side connection terminal which concerns on another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electric power steering device, 2 ... Rack case, 2a ... Motor case, 2b ... Housing, 3 ... Rack shaft, 4 ... Joint, 5 ... Tie rod, 6 ... Steering gear box, 7 ... Input shaft, 8 ... Torsion bar, 9: Steering pinion shaft,
10 ... motor, 11 ... inner rotor, 12 ... outer stator, 13 ... connection sleeve, 14 ... ball nut member, 15 ... bearing, 16 ... male terminal,
20 ... Front opening, 21 ... Mating surface, 22 ... Bottom surface, 23 ... Recess, 24 ... Mounting boss, 25 ... Peeping opening, 26 ... Mating surface,
30 ... Front cover, 31 ... Projection, 32 ... Seal member, 33 ... Screw, 35 ... Top cover, 36 ... Connector, 37 ... Clamping piece, 38 ... Seal member, 39 ... Screw,
40 ... Control board, 41 ... CPU, 42 ... FET, 43 ... Support base, 44 ... Capacitor, 45 ... Relay, 46 ... Female terminal, 47 ... Mounting hole, 48 ... Screw, 49 ... Connector,
50 ... Curing type heat conductive silicone, 54 ... Connection line, 55 ... Current sensor,
60 ... Torque sensor, 61 ... Battery,
70 ... Control board, 71 ... Guide part, 75 ... Board side connection terminal.

Claims (3)

The steering wheel is steered by sliding of the rack shaft (3) engaged with the steering pinion (9) connected to the steering side, and the power of the motor (10) that is driven and controlled according to the steering torque on the steering side is used. In the electric power steering device that is transmitted to the sliding of the rack shaft (3) to assist the steering,
The motor (10) is accommodated in a motor case (2a) of a rack case (2) in which the rack shaft (3) is slidably accommodated,
A housing that accommodates a control board that drives and controls the motor is formed adjacent to the motor case in the rack case,
When the motor (10) is accommodated in the motor case (2a), a conductive plate piece (16a) extending from the motor (10) protrudes into the housing (2b), and the conductive plate piece ( 16a) a rod-like motor side connection terminal (16) projecting vertically near the tip end is positioned at a predetermined position toward the opening (20) of the housing (2b),
A cylindrical board-side connection terminal (46) corresponding to the motor-side connection terminal (16) is fixed to the control board (40) side with one opening directed in the insertion direction to the housing (2b). In addition, a guide member (46b) that is opened in a trumpet shape continuous with an opening facing the insertion direction of the cylindrical board side connection terminal (46) into the housing (2b) is provided,
When the control board (40) is inserted into the housing (2b) from the opening (20) of the housing (2b) so as to face the bottom surface (22), the rod-like motor side connection terminal (16) is simultaneously An electric power steering apparatus characterized by being guided by a guide member (46b) on the control board (40) side, fitted into the cylindrical board side connection terminal (46), and contacted and electrically connected to each other .   2. The electric power steering apparatus according to claim 1, wherein the guide member is configured by extending the cylindrical board side connection terminal. The motor side connection terminal has a round bar shape,
The board side connection terminal has a cylindrical shape,
The electric power steering apparatus according to claim 1, wherein the guide member has a conical shape.

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