JP2008302797A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the degree of freedom in a mounting position of components of an electric power steering device. <P>SOLUTION: The electric power steering device (10) is equipped with a electric motor (12), a controller (14), a fixing base (16) for fixing them and a bus bar (22) arranged in the fixing base (16) in a form of projecting an end (30) and joined to the controller (14) at the end (30) so as to electrically connect the electric motor (12) and the controller (14). The fixing base (16) has at least one mounting part having a plurality of mounting points, and is joined to the controller (14) in one of a plurality of mounting points. The bus bar (22) has a structure constituted of a plurality of conductive thin plates having their ends (30) superposed on one another. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric power steering apparatus mounted on a vehicle, and more particularly to an improvement in a connection structure between an electric motor that applies a steering assist torque to a steering system of a vehicle and a controller that controls driving of the electric motor.

  Many of the vehicles in recent years are equipped with an electric power steering (EPS) device. This electric power steering apparatus generally includes a torque sensor that detects a steering torque applied to the steered wheels, an electric motor that assists the driver's operation, and a controller that controls the driving of the electric motor, and is detected by the torque sensor. The electric motor is driven according to the steering torque. The rotation output of the electric 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.

  Here, regarding the connection configuration of the electric motor and the controller in the electric power steering apparatus, an integrated electric motor and controller has been proposed (see Patent Document 1).

In this prior art, the structure which attaches an electric motor and a controller using a fixed stand is employ | adopted. A bus bar for transmitting a drive current to each motor coil of the electric motor is disposed on the fixed base. The bus bar has an end protruding from the fixed base, and this end is joined to the power line bus bar of the controller with a screw. That is, the controller is fixed to the fixed base by being joined to the fixed base and each of the bus bar ends protruding from the fixed base.
International Publication No. 2007/026894 Pamphlet

  However, in such an electric power steering apparatus, the fixed position between the normal fixing base and the controller is set at the initial stage of the design of the electric power steering apparatus and cannot be changed. Also, since the bus bar is made of a single metal plate having a sufficient cross-sectional area to transmit the drive current and cannot be easily deformed, the joining position between the bus bar and the controller cannot be changed greatly. Therefore, as the design of peripheral devices for electric power steering devices progresses, if the positional relationship between the controller and peripheral devices needs to be changed, for example, to secure clearance, the electric power steering device mold itself must be recreated from the beginning. Will have to. In this case, it is necessary to perform various reliability tests again on the product manufactured by the new mold, which takes a lot of time and cost.

  Therefore, the present invention has been made in view of the above-described problems of the prior art, and its purpose is to increase the degree of freedom of the mounting position of the components of the electric power steering device, particularly the mounting position of the controller on the fixed base. There is.

  To achieve the above object, the present invention provides an electric motor that applies a steering assist torque to a steering system of a vehicle, a controller that controls driving of the electric motor, and a fixed base that fixes the electric motor and the controller. A bus bar electrically connected to the controller by being connected to the controller at the end portion and disposed on the fixing base in a protruding manner. The base has at least one mounting portion having a plurality of mounting points, and is joined to the controller at any one of the plurality of mounting points, and the bus bar has a plurality of conductive thin plates stacked at least at the end portions. The electric power steering device having the above structure is configured.

  According to the above configuration, since the mounting portion provided on the fixed base has a plurality of mounting points, the mounting position of the controller on the fixed base can be selected from a plurality at the stage of mounting. In addition, since the bus bar has a structure in which a plurality of conductive thin plates are stacked at an end portion, the bending rigidity is small and is easily deformed as compared with a single plate having the same cross-sectional area. Therefore, even if there is a change in the joining position of the bus bar and the controller according to the attachment position of the controller to the fixed base being selected at the stage of attachment, the change in the joining position is caused by the deformation of the bus bar end. Can be absorbed. As described above, the degree of freedom of the mounting position of the controller on the fixed base is remarkably improved.

  The attachment portion may be configured by a long hole having a longitudinal direction in the laminating direction of the thin plates, and may be configured to be joined to the controller by a screw inserted through any one of the long holes.

  According to the above configuration, the mounting portion is a long hole having a longitudinal direction in the stacking direction of the thin plate at the end of the bus bar, so that the mounting position of the controller with respect to the fixed base can be changed in the stacking direction of the thin plate. The bus bar end portion is particularly easily deformed in the laminating direction of the thin plates, and therefore, the direction of change of the mounting position of the controller with respect to the fixed base coincides with the direction in which the bus bar end protruding from the fixed base is easily deformed. As a result, the change in the mounting position of the controller and the deformation of the end portion of the bus bar are suitably linked, and the degree of freedom of the mounting position of the controller on the fixed base is further improved.

  Further, the end of the bus bar has a screw insertion hole with a hole formed in the stacking direction of the plurality of thin plates, and is configured to be joined to the controller with a screw inserted into the screw insertion hole. You can also.

  According to the above configuration, the screw insertion hole at the end of the bus bar has a hole in the laminating direction of the thin plate. Therefore, when the bus bar is joined to the controller, the screw tightening direction matches the laminating direction of the thin plate. . Since the bus bar end is particularly easily deformed in the laminating direction of the thin plates, the screw tightening direction to the controller coincides with the direction in which the bus bar end is easily deformed, and the bus bar end and the controller are joined. It becomes easier.

  Moreover, the screw insertion hole provided in the end part of the bus bar can be configured to be a long hole having a longitudinal direction in the protruding direction of the end part.

  According to the above configuration, even if the joining position of the screw that joins the bus bar end portion and the controller is shifted in the protruding direction of the bus bar end portion due to the deformation of the bus bar end portion, this shift is elongated in the protruding direction of the end portion. It can be absorbed by a long hole having a direction.

  The fixing base has a bent portion formed to be bent in a direction perpendicular to a surface for fixing the electric motor, and the mounting portion and the bent portion arranged in the bent portion. Each of the bus bar end portions protruding from the portion is joined to the controller, so that the controller can be fixed to the fixing base.

  According to the above configuration, the controller includes the mounting portion (the plurality of mounting points) arranged in the bending portion of the fixing base (formed so as to be bent in a direction perpendicular to the fixing surface of the electric motor and the fixing base). In this case, the attachment position can be changed in a direction perpendicular to the fixing surface of the electric motor and the fixing base. At this time, the end portion of the bus bar protrudes from the bent portion and can be deformed in accordance with the change in the mounting position in the vertical direction with respect to the fixed base of the controller. Thereby, the freedom degree of the attachment position to the fixed base of a controller further improves.

  ADVANTAGE OF THE INVENTION According to this invention, the freedom degree of the attachment position of the component of an electric power steering apparatus, especially the attachment position with respect to the fixed base of a controller can be raised.

Hereinafter, embodiments of the present invention will be described in the following order based on the drawings.
1. Overall configuration of an electric power steering apparatus according to an embodiment of the present invention:
2. Configuration relating to mounting of a controller according to an embodiment of the present invention:
3. Modified example of the electric power steering apparatus according to the embodiment of the present invention:
In the drawings, the same components are denoted by the same reference numerals.

1. Overall configuration of an electric power steering apparatus according to an embodiment of the present invention:
Hereinafter, the overall configuration of an electric power steering apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

  Here, FIG. 1 is a side view of an electric power steering apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view of an electric motor and a fixing base according to the embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. It is a perspective view of the controller concerning an example.

  First, an outline of the electric power steering apparatus according to the present embodiment will be described with reference to FIG. As shown in FIG. 1, an electric power steering (EPS) device 10 includes a housing 26, an output shaft 28, an electric motor 12 having a fixed base 16, a bus bar 22, a controller (ECU) 14 having a housing 34, and a housing. 34 is provided with a terminal block 40 disposed at the bottom.

  The fixed base 16 includes a bent portion 161 that is bent in a direction perpendicular to a boundary surface (a surface that fixes the electric motor) with the casing 26, and in the bent portion 161, the casing of the controller 14. 34 and a screw 58. Further, the end portion 30 of the bus bar 22 protrudes from the bent portion 161. The end 30 of the bus bar 22 and the housing 34 of the controller 14 are joined together by screws 60 via the terminal block 40. The bus bar 22 electrically connects the controller 14 and the electric motor 12, and the motor drive current from the controller 14 is transmitted to the electric motor 12.

  Hereinafter, the configuration of each part of the electric power steering apparatus 10 will be described more specifically. First, the configuration of the electric motor 12, the fixed base 16, and the bus bar 22 will be described with reference to FIG.

  As shown in FIG. 2, the electric motor 12 is configured by, for example, a three-phase brushless motor as a motor that applies steering assist torque to the steering system of the vehicle, and an output shaft is provided in a cylindrical housing 26. 28 (shown in FIG. 1) is rotatably inserted. The output shaft 28 is connected to a steering mechanism (not shown) as a steering system. The casing 26 accommodates a rotor (not shown) to which a permanent magnet constituting the magnetic pole is fixed, a stator (not shown) arranged around the rotor and fixed to the casing 26, and the like. Has been. The stator includes, for example, a motor coil (armature winding) composed of three phases of U phase, V phase, and W phase.

  The fixed base 16 is formed integrally with the electric motor 12 by extending components of the electric motor 12, for example, a motor flange or a motor case. Two screw insertion holes 18 for fixing the electric motor 12 to a gear box (not shown) are symmetrically arranged on the fixing base 16 with respect to the casing 26 (only one is shown in FIG. 2). . The bent portion 161 is formed with two screw insertion holes 20 (attachment portions) for fixing the controller 14.

  Three bus bars 22 are arranged on the fixed base 16. Each bus bar 22 is configured by laminating three layers of thin metal plates. A groove 24 for arranging the three bus bars 22 is formed in the fixed base 16, and the insulating resin 25 is filled in the groove 24. Thus, the three bus bars 22 are covered with the insulating resin 25 and the bus bars 22 are insulated from each other with the insulating resin 25. Each bus bar 22 is electrically connected to the above-described motor coil composed of the three phases U phase, V phase, and W phase at one end. The other end 30 of the bus bar 22 protrudes from the main surface of the bent portion 161 in the normal direction of the main surface. A screw insertion hole 32 having a longitudinal direction in the same direction (in the present embodiment, the protruding direction of the end portion 30) is formed in the end portion 30 of each bus bar 22.

  Next, the configuration of the controller 14 will be described with reference to FIG. As shown in FIG. 3, the controller 14 includes a housing 34 formed in a substantially rectangular parallelepiped shape. Two screw insertion holes 36 for fixing the casing 34 to the fixing base 16 are formed on the side surface of the casing 34 corresponding to the screw insertion holes 20 of the fixing base 16. Three terminal blocks 40 are fixed to the bottom of the housing 34. Each terminal block 40 is formed with a screw insertion hole 42 corresponding to the screw insertion hole 32 of each bus bar 22, and a nut is disposed on the back side of each screw insertion hole 42. Each screw insertion hole 42 is formed such that its longitudinal direction is orthogonal to the longitudinal direction of the screw insertion hole 32 of the bus bar 22. In the housing 34, a drive circuit (not shown) that receives a signal from a torque sensor (not shown) that detects a steering force, information that represents a vehicle running state such as a steering angle and a vehicle speed, and generates a motor drive current ( (Not shown) and the like are stored. This drive circuit outputs a motor drive current to a terminal block 40 via U-phase, V-phase, and W-phase power line bus bars (not shown). Each power line bus bar is a terminal block. The 40 screw insertion holes 42 are electrically connected.

  By joining the bus bar 22 to the controller 14 via the terminal block 40, the end portions 30 of the three bus bars are electrically connected to the U-phase, V-phase, and W-phase power line bus bars. As described above, the other end of the three bus bars 22 is electrically connected to the motor coils formed of the three phases of the U phase, the V phase, and the W phase. The motor 12 is electrically connected via the bus bar 22. As a result, the motor drive current from the controller 14 is transmitted to the electric motor 12.

  The housing 34 is made of a metal material. However, since the terminal block 40 is disposed so as to protrude from the bottom of the housing 34, the housing 34 is attached to the fixed base 16. Even if it fixes with a screw | thread, it can prevent that the housing | casing 34 contacts with each bus-bar 22 and short-circuits.

2. Configuration relating to mounting of a controller according to an embodiment of the present invention:
The configuration related to the mounting of the controller 14 to the fixed base 16 and the bus bar 22 is a particularly characteristic configuration in the present embodiment. The following (1) configuration of the bus bar (2) configuration of the mounting portion (3) to the fixed base of the controller These are roughly divided into three examples of attachment and will be described with reference to FIGS.

  Here, FIG. 4 is a top perspective view of the bent portion of the fixing base and the bus bar according to the embodiment of the present invention, and FIG. 5 is a schematic view showing a state where the controller is attached to the fixing base according to the embodiment of the present invention. FIG. 6 (a) is a side view when the controller according to the embodiment of the present invention is attached to the upper side of the screw insertion hole of the fixing base, and FIG. 6 (b) is the controller according to the embodiment of the present invention. It is a side view at the time of attaching to the lower side of the screw insertion hole of a fixed base.

(1) Configuration of Bus Bar As shown in FIG. 4, the three bus bars 22 are formed so that each end 30 protrudes from the side surface of the bent portion 161 and is arranged substantially in the same plane. . The end 30 has a rectangular cross section, and has a cross-sectional area of a size necessary for transmitting the drive current output from the controller 14 to the electric motor 12.

  The bus bar 22 has a structure in which three thin metal plates 301, 302, and 303 having the same shape are sequentially stacked (hereinafter, the direction in which the thin metal plates 301, 302, and 303 are stacked, that is, the direction of the arrow X in FIG. 4). "Lamination direction"). By configuring in this way, the rigidity in the stacking direction of the end portion 30 of the bus bar 22 is reduced as compared to the case where the bus bar 22 is configured by a single metal plate of the same material having the same cross-sectional area. That is, the bus bar 22 has a structure that is remarkably easy to deform in the stacking direction while having a cross-sectional area necessary for transmitting the drive current output from the controller 14 to the electric motor 12. Therefore, the end 30 of the bus bar 22 can be easily deformed even if a force is applied vertically in the stacking direction.

  A screw insertion hole 32 is formed at the distal end portion of the end portion 30. The screw insertion hole 32 has a hole in the stacking direction. Therefore, the tightening direction of the screw and the stacking direction, that is, the direction in which the bus bar 22 is easily deformed substantially coincide with each other, and the end portion 30 is easily deformed in the stacking direction when tightening the screw. Further, the screw insertion hole 32 is a long hole having a longitudinal direction in the projecting direction of the end portion 30 (the direction indicated by the arrow Y in FIG. 5 and hereinafter referred to as “projecting direction”). Thereby, even if the attachment position with the controller 14 fluctuates back and forth in the protruding direction in conjunction with the vertical deformation of the end portion 30 in the stacking direction, the screw tightening position can be moved within the range of the elongated hole. The fluctuation can be absorbed.

(2) Configuration of Attachment Portion As shown in FIG. 4, the bent portion 161 is formed with two screw insertion holes 20 (attachment portions) that are long holes having a longitudinal direction in the stacking direction. As shown in FIG. 5, the diameter of the screw insertion hole 20 in the longitudinal direction is sufficiently larger than the diameter of the screw 58 inserted through the screw insertion hole 20. Therefore, when the controller 14 is attached to the fixed base 16, the screw insertion hole 20 (attachment portion) has a plurality of attachment points. More specifically, a desired attachment point is selected by moving the insertion position of the screw 58 into the screw insertion hole 20 up and down in the longitudinal direction of the screw insertion hole 20, and the controller 14 is attached to the fixed base 16. be able to.

(3) Example of attachment of controller to fixing base In this embodiment, the longitudinal direction of the screw insertion hole 20 coincides with the stacking direction. That is, the controller 14 can be moved up and down in the stacking direction when attached to the fixed base 16. With this movement, the terminal block 40 fixed to the housing 34 of the controller 14 also moves up and down in the stacking direction. Then, the joining position between the terminal block 40 and the end 30 of the bus bar 22 also moves up and down in the stacking direction. However, in this embodiment, as described in the above (1), the end 30 of the bus bar 22 has a laminated structure of thin metal plates, and can be easily deformed up and down in the laminating direction. Even if the position moves up and down, the change in the position can be absorbed by the bus bar end 30 being deformed in the same direction. This situation is shown in FIGS. 6 (a) and 6 (b).

  FIG. 6A shows a case where the casing 34 of the controller 14 is attached above the long hole of the screw insertion hole 20 of the bent portion 161. Although the terminal block 40 is moving upward as the casing 34 moves, the end 30 of the bus bar 22 is easily deformed in the same direction as the terminal block 40. Therefore, the controller 14 and the bus bar 22 can be joined without applying an excessive load to each component. This is particularly effective when, for example, it becomes necessary to secure the clearance A with the peripheral device L arranged on the upper side of the electric power steering apparatus 10 at the stage of attachment.

  On the other hand, FIG. 6B shows a case where the casing 34 of the controller 14 is attached with a screw below the long hole of the screw insertion hole 20 of the bent portion 161. The terminal block 40 moves downward as the casing 34 moves, but the end 30 of the bus bar 22 is also easily deformed in the same direction as the terminal block 40. Therefore, also in this case, the controller 14 and the bus bar 22 can be joined without applying an excessive load to each component. This is particularly effective when, for example, it becomes necessary to secure a clearance B with the peripheral device M arranged on the lower side of the electric power steering apparatus 10 at the stage of attachment.

  As described above, the mounting position of the controller 14 on the fixed base 16 can be selected from a plurality of points, and the bus bar 22 has a structure that can be deformed in accordance with the variation of the mounting position of the controller 14. The degree of freedom of the mounting position with respect to the fixed base 16 is improved. As a result, even if it becomes necessary to change the mounting position to ensure clearance with peripheral devices at the stage of mounting the controller 14 to the fixed base 16, the design of the electric power steering device 10 is designed from the beginning. There is no need to redo, and it is possible to prevent the occurrence of a second reliability test or the like caused by such a redo of the design.

3. Modified example of the electric power steering apparatus according to the embodiment of the present invention:
As mentioned above, although the Example of this invention was shown, this invention is not limited to this Example, In the range which does not deviate from the summary, implementation in various aspects is possible. For example, the following modifications are possible.

  In the said Example, the attachment part of the fixing stand 16 and the controller 14 is comprised by the long hole which makes a lamination direction a longitudinal direction, and makes the diameter of this long hole larger than the diameter of the screw penetrated to the said long hole. Therefore, it is configured to have a plurality of attachment points. However, for example, the mounting portion may be configured by arranging a plurality of screw insertion holes (not necessarily long holes) in a straight line in the stacking direction, and may have a plurality of mounting points as a whole. .

  Further, in the above embodiment, the bus bar 22 has a structure in which three thin metal plates 301, 302, and 303 having the same shape are sequentially laminated. However, the bus bar 22 should just be comprised with the some thin plate in which the edge part 30 which protrudes from the fixing stand 16 has an electroconductive material. For example, the bus bar 22 may be configured by changing the number of thin plates to be stacked, or by stacking thin plates having different cross-sectional shapes. By configuring in this way, without changing the cross-sectional area of the bus bar 22 (that is, having a cross-sectional area of a size necessary for transmitting the drive current output from the controller 14 to the electric motor 12), The rigidity of the bus bar 22 can be adjusted to a desired direction and size. Further, a U-shaped portion bent in a U-shape in the stacking direction is formed in the bus bar 22 between the screw insertion hole 32 and the base portion of the end portion 30 (the portion where the bus bar 22 protrudes from the bent portion 161). May be. Even if the screw insertion hole 32 is easily deformed in the stacking direction by virtue of the U-shaped structure, the U-shaped portion is deformed according to the vibration, and the stress associated with the vibration is endless. Concentration on the insulating resin 25 from the root portion of the portion 30 can be mitigated.

  In the above embodiment, the controller 14 and the bus bar 22 are connected by screws via the terminal block 40 formed as a separate part to the controller 14. However, the terminal block 40 is, for example, a housing of the controller 14. The bus bar 22 may be directly joined to the controller 14 without using the terminal block 40.

  Moreover, in the said Example, although the fixed base 16 showed the structure integrally formed as a part of component of the electric motor 12, each is comprised as a different separate part, for example, the electric motor 12 is made into the fixed base 16. It can also be fixed with screws or the like.

1 is a side view of an electric power steering apparatus according to an embodiment of the present invention. The perspective view of the electric motor and fixed base which concern on the Example of this invention. The perspective view of the controller which concerns on the Example of this invention. The upper part perspective view of the bending part and bus bar of the fixed base which concerns on the Example of this invention. The schematic diagram which shows the state by which the controller was attached to the fixed base which concerns on the Example of this invention. (A) The side view at the time of attaching the controller which concerns on the Example of this invention to the upper side of the screw penetration hole of a fixed base. (B) The side view at the time of attaching the controller concerning the Example of this invention to the lower side of the screw insertion hole of a fixed base.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electric power steering apparatus 12 Electric motor 14 Controller 16 Fixing base 161 Bending part 18, 20, 32, 36, 42 Screw insertion hole 22 Bus bar 24 Groove 25 Insulating resin 26, 34 Case 28 Output shaft 30 End part 301, 302, 303 Thin metal plate 40 Terminal block 58, 60 Screw

Claims (5)

An electric motor for providing steering assist torque to the steering system of the vehicle;
A controller for controlling the driving of the electric motor;
A fixing base for fixing the electric motor and the controller;
A bus bar electrically connected to the electric motor and the controller by being disposed on the fixed base in a form in which the end projects, and being joined to the controller at the end;
The fixed base has at least one attachment portion having a plurality of attachment points, and is joined to the controller at any one of the plurality of attachment points,
The bus bar is an electric power steering device having a structure in which a plurality of conductive thin plates are stacked at least at the end portion.   2. The electric power steering apparatus according to claim 1, wherein the attachment portion is configured by a long hole having a longitudinal direction in a laminating direction of the thin plates, and is joined to the controller by a screw inserted into one point of the long hole. .   3. The electric motor according to claim 2, wherein an end portion of the bus bar has a screw insertion hole having a hole formed in the stacking direction of the plurality of thin plates, and is joined to the controller with a screw inserted into the screw insertion hole. Power steering device.   The electric power steering apparatus according to claim 3, wherein the screw insertion hole provided in the end portion of the bus bar is a long hole having a longitudinal direction in a protruding direction of the end portion.   The fixed base has a bent portion formed so as to be bent in a direction perpendicular to a surface to which the electric motor is fixed, and from the mounting portion and the bent portion arranged in the bent portion. The power steering device according to any one of claims 1 to 4, wherein each of the protruding bus bar end portions and the controller are joined to each other so that the controller is fixed to the fixed base.

Images