JP5229612B2 - Electric power steering device - Google Patents

Description

  The present invention relates to an electric power steering device mounted on a vehicle. More specifically, the present invention relates to the structure of a control unit (ECU) of an electric power steering apparatus.

  In recent years, many vehicles are equipped with an electric power steering (EPS) device. The electric power steering apparatus generally includes a torque sensor that detects a steering torque applied to the steering transfer, a motor that assists the operation of the driver, and an ECU that controls the driving of the motor, and is detected by the torque sensor. The motor is driven according to the steering torque. The rotation output of the motor becomes a steering assist torque, and this rotation output is decelerated by the gear mechanism and transmitted to the output shaft of the steering mechanism. Thus, the vehicle is steered while assisting the steering force applied to the steering wheel.

  Conventionally, as such an electric power steering device, an electromechanical integrated structure (a structure in which an actuator unit and an electronic control unit are integrally provided) has been disclosed. In such an electric power steering device, for example, a motor and a control unit (control unit) are arranged in parallel in a gear box, and at least one of the connection terminal and the terminal block is disposed at a position facing the motor and the control unit. It is formed so as to protrude in a direction crossing the direction.

Further, as an electric power steering apparatus having a close arrangement structure, there is a conventional one disclosed in Patent Document 1, for example. The control unit is arranged near the motor, and the motor terminal connection is made with a bus bar protruding from the opening of the control unit and connected to the relay wire connected to the motor coil provided inside the motor with a screw. That's it.
Japanese Patent No. 3593102

  However, in the electric power steering apparatus configured as described above, versatility and layout flexibility may be limited. That is, in the conventional electric power steering apparatus, the mounting location of the control unit varies depending on the vehicle type, so the control unit has to change the control unit structure itself, such as its board configuration, case shape, and connector position. Is in a situation where For this reason, new development and design must be performed for each vehicle type.

  Further, in the case of an electromechanical integrated structure, if it is attempted to arrange it at a position away from the gear box, a significant design change including the shape of the control unit and the circuit board may be required.

  Furthermore, in the case of the proximity arrangement structure in which the control unit is arranged in the vicinity of the motor as in Patent Document 1, when the connection terminal position or the connector position is desired to be changed, or when the arrangement of the electromechanical integrated structure is attempted, a large design Changes are expected.

  Therefore, an object of the present invention is to provide an electric power steering device having a structure that can be mounted on a vehicle without requiring a significant design change even if the mounting position of the control unit is changed.

  In order to achieve the above object, the present invention provides a motor capable of applying a steering assist torque and an electric power steering apparatus including a control unit for driving the motor. The control unit includes a control circuit board on which various electronic components are mounted. And a power circuit board on which a semiconductor switching element for driving a motor is mounted, and the control circuit board is larger than the power circuit board.

  Further, the present invention provides an electric power steering apparatus including a motor capable of applying a steering assist torque and a control unit for driving the motor. The control unit includes a control circuit board on which various electronic components are mounted, and a motor driving motor. The distance A between the control circuit board and the power circuit board is the most among the parts that are mounted on the control circuit board and do not protrude outside the electric power steering device. It is characterized by being not more than the height B of the tall component.

  According to the present invention as described above, it is easy to reduce the size of the control unit, and thus the apparatus on which it is mounted. For this reason, even if the mounting location of the control unit changes for each vehicle type, it is possible to suppress changes in the board configuration, case shape, connector position, and the like of the control unit as compared with the conventional case. Therefore, it is possible to realize a device having a structure that can be mounted on a vehicle without requiring a significant design change even if the mounting position of the control unit is changed, while limiting the versatility and layout flexibility of the electric power steering device. .

  Further, the present invention provides an electric power steering apparatus including a motor capable of applying a steering assist torque and a control unit for driving the motor. The control unit includes a control circuit board on which various electronic components are mounted, and a motor driving motor. Consists of a power circuit board that mounts semiconductor switching elements, etc., and the motor connection terminal that is electrically connected to the terminal on the motor side is covered with an insulating member and extended so that it can be placed on any side of the control unit It is characterized by being.

  In the electric power steering apparatus in which the motor connection terminal is covered with an insulating member, the motor connection terminal can be connected to the motor at an arbitrary location on the outer periphery of the control unit by wiring the motor connection terminal inside the control unit. According to this, even if the mounting location of the control unit changes for each vehicle type, it is possible to respond without changing the structure of the control unit itself such as the board configuration, case shape, connector position of the control unit. Is possible. Thus, since versatility and layout flexibility are improved, the electric power steering apparatus according to the present invention can omit new development and design for each vehicle type. Further, since the shape can be set according to the vehicle layout without changing the control circuit unit, the versatility is high, and the development, design, and manufacturing period can be shortened.

  In this electric power steering apparatus, the motor connection terminal is preferably extended and wired in the case when the position connected to the substrate and the position connected to the motor terminal exist on different sides of the control unit.

  In the electric power steering apparatus, it is also preferable that the case is provided with a portion for guiding the motor connection terminal. For example, when the motor connection terminal is extended and wired in the case, it can be used as a guide for routing the wiring.

  Further, the present invention provides an electric power steering apparatus including a motor capable of applying a steering assist torque and a control unit for driving the motor. The control unit includes a control circuit board on which various electronic components are mounted, and a motor driving motor. When the motor and control unit are arranged close to each other, the distance between each terminal of the motor connection terminals that are electrically connected to the motor side terminals is equidistant. And is arranged symmetrically in alignment with the center of the position of the fixing member of the control unit.

  In such an electric power steering device, even if it is a close arrangement structure in which the control unit is arranged in the vicinity of the motor, a large design is required when the connection terminal position or the connector position is to be changed or when the arrangement of the electromechanical integrated structure is attempted. It is possible to avoid changes. Therefore, even if the mounting position of the control unit is changed, it is possible to realize an electric power steering device having a structure that can be mounted on a vehicle without requiring a significant design change. In addition, if the unit structure is detachable only with bolts, for example, in the case of an electromechanical integrated structure, it is not necessary to perform electrical connection such as soldering or welding when assembling the control unit. It is possible to improve.

  According to the electric power steering apparatus of the present invention, even if the mounting position of the control unit is changed, it can be mounted on the vehicle without requiring a significant design change.

  Hereinafter, an embodiment of an electric power steering apparatus according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a general configuration example of an electric power steering apparatus. In this electric power steering apparatus, the column shaft 2 of the steering handle 1 is coupled to a tie rod 6 of a steering wheel via a gear box 3 of a reduction gear, universal joints 4a and 4b, and a pinion rack mechanism 5. The column shaft 2 is provided with a torque sensor 10 that detects the steering torque of the steering handle 1, and a motor 20 that assists the steering force of the steering handle 1 is connected to the column shaft 2 via the gear box 3. ing. The control unit (ECU) 30 that controls the electric power steering apparatus is supplied with electric power from the battery 14 and also receives an ignition key signal from the ignition key 11. Based on the steering torque value T detected by the torque sensor 10 and the vehicle speed V detected by the vehicle speed sensor 12, the control unit 30 calculates an assist command steering assist command value I using an assist map or the like. Based on the calculated steering assist command value I, the current supplied to the motor 20 is controlled. The control unit 30 is mainly composed of a CPU (or MPU or MCU).

  In FIG. 2, the external view of the main components of the electric power steering apparatus in this embodiment is shown. As shown in the figure, this electric power steering apparatus includes a motor 20 capable of applying a steering assist torque, a control unit 30 for driving the motor 20, a gear box 3 for a reduction gear, and the like.

FIG. 3 is an exploded perspective view of main components of the electric power steering apparatus according to the present embodiment. As illustrated, con preparative roll unit 30 in this embodiment has a configuration and a control circuit board 40 and the power circuit board 50. For example, in the present embodiment, the power board 50 is attached to the heat sink 32, the motor connection terminal 60 and the control circuit board 40 are further attached, and the cover 31 is covered thereon (see FIG. 3A and the like). ). For example, in this embodiment, the cover 31 and the heat sink 32 form a control unit case (shown with reference numeral 35 in FIG. 10).

  The control circuit board 40 is a board on which various electronic parts such as a microcomputer, a connector, a relay, and a noise countermeasure part are mounted. In the control circuit board 40 shown in FIG. 4, after mounting electronic components such as a microcomputer, the electronic components are mounted so that a through hole exists at a connection portion with the power circuit board 50. For example, the control circuit board 40 of this embodiment has a configuration in which a connector 41, a coil 42, a power relay 43, an aluminum electrolytic capacitor 44, and the like are attached to the board (see FIG. 4B).

  The power circuit board 50 is a board on which a semiconductor switching element for driving a motor is mounted. In the power circuit board 50 shown in FIG. 5, connection lead terminals 51 for electrically connecting to the control circuit board 40 are further mounted. If the connection lead terminal 51 has a shape or structure that can relieve stress when an external force is applied, the connection lead terminal 51 can be connected even if a relative position change occurs between the control circuit board 40 and the power circuit board 50 due to thermal expansion or the like. It is preferable because the reliability of the part can be improved.

  The power circuit board 50 is generated on the power circuit board 50 by fixing the lower surface of the board in contact with a flat surface provided on the control unit case 35 (for example, the surface of the heat sink 32 described above). Heat can be dissipated (see FIG. 3A). Thus, when the power circuit board 50 is fixed to the control unit case 35, heat can be efficiently transferred by inserting heat radiation grease or a heat radiation sheet between the plane of the control unit case 35 and the power circuit board 50. it can. Alternatively, when the gear box 3 is used as a heat sink, it is desirable that the control unit case 35 is fixed in contact with a flat surface provided on the gear box 3 to radiate heat. In this case, heat can be efficiently transferred by placing heat radiation grease or a heat radiation sheet between the plane of the control unit case 35 and the plane of the gear box 3.

  Here, the distance A between the control circuit board 40 and the power circuit board 50 is the tallest part (for example, a capacitor or the like) that is mounted on the control circuit board 40 and does not protrude to the outside of the electric power steering device. It is preferable that the height is equal to or lower than the height B (A ≦ B) of a coil or the like, and the component is indicated by reference numeral 45 in FIG. In such a case, it is easy to reduce the size of the control unit 30 and thus the apparatus on which it is mounted. For this reason, even if the mounting location of the control unit 30 changes for each vehicle type, changes in the board configuration, case shape, connector position, etc. of the control unit 30 can be suppressed as compared with the conventional case.

  The motor connection terminal 60 electrically connected to the terminal on the motor 20 side is covered with an insulating member such as a resin mold. The motor connection terminal 60 is preferably extended so that it can be disposed on any side of the control unit 30. In the electric power steering apparatus in which the motor connection terminal 60 is covered with an insulating member, the motor connection terminal 60 can be connected to the motor at an arbitrary position on the outer periphery of the control unit by wiring the motor connection terminal 60 inside the control unit 30. It becomes possible (see FIG. 10). In such a case, even if the mounting location of the control unit changes for each vehicle type, it is possible to respond without changing the structure of the unit itself, such as the board configuration, case shape, and connector position of the control unit 30. It becomes possible. The motor connection terminal 60 is more preferably extended and wired in the control unit case 35 when the position connected to the substrate and the position connected to the motor terminal are on different sides of the control unit 30 ( (See FIG. 10). It is also preferable that the control unit case 35 is provided with a portion for guiding the motor connection terminal 60. For example, when the motor connection terminal 60 is extended and wired in the control unit case 35, it can be used as a guide for routing the wiring. As described above, if the motor connection terminal 60 is wired inside the control unit 30, the control unit 30 and the motor 20 can be connected at an arbitrary position on the outer periphery of the control unit. Layout flexibility is improved.

  FIG. 6 is a diagram showing a variation example of the motor connection terminal 60 (see FIGS. 6A to 6D). “Motor connection terminal position (1)” in the figure indicates that the position of the connection portion 60a of the motor connection terminal 60 relative to the control circuit board 40 and the position of the motor-side terminal 60b are different sides of the control unit 30 ( It is an example in the case of existing in the surface). The motor connection terminal 60 in this case has a shape that extends inside the control unit case 35 to the position of the motor-side terminal 60b without changing the connection position with the control circuit board 40 (FIG. 6A). (See (B)). On the other hand, “motor connection terminal position (2)” in the figure indicates that the position of the connection portion 60a of the motor connection terminal 60 with respect to the control circuit board 40 and the position of the motor-side terminal 60b are the same as those of the control unit 30. This is an example in the case of being on a side (or surface) (see FIGS. 6C and 6D). 6A and 6C show a so-called terminal block type motor connection terminal 60, and FIGS. 6B and 6D show a so-called bus bar type motor connection. Terminal 60.

  FIG. 7 is a view showing a variation example of the mounting location of the control unit 30 (see FIGS. 7A to 7F). The first stage shown in FIG. 7 is a proximity arrangement structure in which the control unit 30 is placed vertically with respect to the motor 20 and the power supply and signal connector are arranged on the motor end. (See FIGS. 7A and 7B). In this case, the gear box 3 or the motor 20 is provided with a fixing portion of the control unit 30 (a place where the control unit 30 is fixed or a device for fixing). 7 shows a proximity arrangement structure in which the control unit 30 is placed vertically with respect to the motor 20 and a power supply and signal connector are arranged beside the motor 20. (See FIGS. 7C and 7D). In this case, a fixing portion of the control unit 30 is provided in the gear box 3 or the motor 20. The third stage of FIG. 7 shows an electromechanical integrated structure in which a power source and a signal connector are arranged at the end of the worm housing portion of the gear box 3 (FIGS. 7E and 7F). reference). Note that, as described above, FIG. 7 only shows a variation example of the mounting location of the control unit 30, and the control unit 30 can be arranged around the worm shaft within a range that does not interfere with other parts. is there.

  Further, the assembly of the motor 20, the control unit 30 and the like can have variations in the assembly order in accordance with the manufacturing process of the main components shown in FIG. Thereby, it becomes possible to improve the freedom degree of the manufacturing process of main component parts. A variation example of the assembly order will be described as follows. That is, there is a variation in which the motor 20 is first assembled to the gear box 3 and then the control unit 30 is assembled to the gear box 3 (see FIGS. 7A to 7D). On the contrary, the control unit 30 may be first assembled to the gear box 3, and then the motor 20 may be assembled to the gear box 3 (see FIGS. 7E and 7F). Alternatively, the control unit 30 may be assembled to the motor 20 and then the motor 20 may be assembled to the gear box 3.

  FIG. 8 is a view showing a variation example of the control unit case 35. In the control unit case 35 shown here, the heat sink 32 and the control unit fixing part are made of aluminum, and the side surface of the case and the connectors 41 ′ are integrated with resin. In FIG. 8, the side surface portion of the resin case in which the connectors 41 ′ are integrated is indicated by reference numeral 33.

  Here, when the motor 20 and the control unit 30 are arranged close to each other as described above, the motor connection terminals 60 electrically connected to the terminals on the motor 20 side are arranged at equal intervals. It is preferable that the control unit 30 is arranged symmetrically in alignment with the center of the position of the fixing member (for example, fixing bolt) 34 (see FIG. 11). In such an electric power steering apparatus, even when the control unit 30 is arranged in the vicinity of the motor 20, when it is desired to change the connection terminal position or the connector position, or when an arrangement of an electromechanical integrated structure is attempted. It is possible to avoid large design changes. For example, in the present embodiment, the fixing position of the control unit 30 (more specifically, the center position between the plurality of fixing members 34 in the control unit 30) and the center of the motor connection terminal 60 are arranged and symmetrical. Therefore, the mounting direction of the control unit 30 can be reversed without changing the connection terminal shape (see FIG. 11 and the like). In such a case, for example, even if the control unit 30 is rotated 180 degrees around the terminal, it can be attached without changing the shape of the terminal portion (see FIGS. 7C, 7D, etc.).

  Next, the assembly process of the control unit 30 will be described (see FIG. 7 and the like).

  First, heat radiation grease is applied to a plane formed on the control unit case 35, and the power circuit board 50 is fixed to a predetermined position of the gear box 3. Then, in order to position the lead from the power circuit board 50, the power circuit board 50 is abutted against the surface formed on the gear box 3 and is installed at a predetermined position, and is fixed by screwing or the like. Next, the motor connection terminal component is fixed to a predetermined position of the gear box 3 with a snap fit, a screw or the like. Next, the motor terminal block component and the lead terminal 51 from the power circuit board 50 are installed in the through hole of the control circuit board 40 and fixed to the control unit case 35 by screwing or the like. Next, the lead terminals 51 are electrically connected by soldering. Next, the control unit 30 is configured by attaching the cover 31.

  Subsequently, an assembly process of the control unit 30 and the motor 20 will be described.

  The control unit 30 and the motor 20 are assembled in accordance with the mounting location shown in FIG. Note that the mounting location illustrated in FIG. 7 is a basic example, and the control unit 30 can be mounted in a range rotated about the motor shaft, and further mounted in a range rotated about the column shaft axis. It is. At this time, the control unit 30 is assembled from the direction in which the control unit alone can be attached and detached. Further, a connection terminal is provided at a connection portion between the control unit 30 and the motor 20 from the control unit 30 side and the motor 20 side, respectively, and a cover 31 is attached. Depending on the mounting location, each terminal (motor connection terminal 60) is set and connected to a terminal block type or a bus bar type as shown in FIG.

  As described above, since the electric power steering device according to the present embodiment can cope with various mounting locations for changes in the configuration and arrangement of the circuit board, the design change can be minimized. The development and design man-hours can be greatly reduced, resulting in quick delivery and cost reduction effects. Specifically, for example, even if the mounting position of the control unit 30 is changed, it is possible to mount the control circuit board 40 and the power circuit board 50 without changing the connection relationship between them, depending on the vehicle layout. Versatile because it can be handled as appropriate. Further, by appropriately changing the shape of the control unit case 35 and the motor connection terminal 60, it is possible to provide a close arrangement structure close to the motor 20 or an electromechanical integrated structure directly coupled to the gear box 3.

  Furthermore, in the electric power steering apparatus of the present embodiment, large components such as capacitors and coils can be changed according to the motor output and other requirements without changing the configuration and arrangement of the substrate. In other words, in this embodiment, the parts that require design changes due to the motor current size and vehicle layout constraints are limited to module parts, and development and evaluation can be performed by making the board a common specification (platforming). The man-hour can be reduced.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, if all the electrical connections between the control circuit board 40 and the power circuit board 50 are performed by soldering via the control circuit board 40, soldering between components can be performed only on one surface. Can be done. In such a case, the assembly process can be further simplified.

It is a figure showing an example of composition of a general electric power steering device. 1 is an external view of main components of an electric power steering apparatus according to an embodiment of the present invention. It is a perspective view which decomposes | disassembles and shows the main components of an electric power steering apparatus, Comprising: Two forms from which the position of a motor connection terminal differs are shown as (A) and (B). It is (A) external view and (B) exploded perspective view of a control circuit board. It is an external view of a power circuit board. It is a figure which shows the example of a variation of the terminal for motor connection. It is a figure which shows the example of a variation of a control unit mounting location. It is a figure which shows the example of the control unit case using resin. It is (A) top view, (B) front view, and (C) side view which show one form of the control unit which aimed at size reduction. It is a top view which shows the control unit from which the position of a motor connection terminal differs in (A) and (B), respectively. It is a side view showing an example of a control unit in which motor connection terminals are arranged symmetrically in alignment with the center of the position of the fixing member of the control unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Gear box, 20 ... Motor, 30 ... Control unit, 34 ... Fixing bolt (fixing member), 35 ... Control unit case (case), 40 ... Control circuit board, 45 ... Mounted on the control circuit board The tallest component that does not protrude to the outside of the electric power steering device, 50 ... power circuit board, 60 ... motor connection terminal

Claims (4)

In an electric power steering apparatus including a motor capable of applying steering assist torque and a control unit for driving the motor,
The control unit is configured in two layers by a control circuit board on which various electronic components are mounted and a power circuit board on which a semiconductor switching element for driving a motor is mounted
It said control circuit board is much larger than the power circuit board,
The motor connection terminal that is electrically connected to the terminal on the motor side is covered with an insulating member, and extended so that it can be placed on any side of the control unit,
The electric power steering apparatus according to claim 1, wherein the motor connection terminal is extended and wired in a case when the position connected to the substrate and the position connected to the motor terminal are on different sides of the control unit . The electric power steering apparatus according to claim 1 , wherein the case is provided with a portion for guiding the motor connection terminal. When the motor and the control unit are arranged close to each other, the distance between the terminals of the motor connection terminal electrically connected to the terminal on the motor side is arranged at equal intervals, and the fixing member of the control unit 2. The electric power steering apparatus according to claim 1 , wherein the electric power steering apparatus is arranged symmetrically in alignment with the center of the position. The distance A between the control circuit board and the power circuit board is equal to or less than the height B of the tallest part mounted on the control circuit board and not projecting outside the electric power steering device. The electric power steering apparatus according to claim 1.

Images