JP2007203916A - Electric power steering system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering system capable of reducing noise against a vehicle body. <P>SOLUTION: In this on-vehicle electric power steering system 3, an electric motor 3b generates a steering auxiliary force corresponding to steering torque generated in a steering shaft so as to give the steering auxiliary force to a steering system. The ground terminal of an ECU 3a for controlling the electric motor 3b to be rotated corresponding to a steering direction is connected to a vehicle body portion near an installation position of the electric power steering system 3 installed on a vehicle by a ground harness 7b, recovering noise components generated by the electric motor 3b to the ECU 3a before the noise components are transmitted to over the whole vehicle body 1, thereby attaining noise reduction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric power steering apparatus, and is suitable for application to an electric power steering apparatus mounted on a vehicle such as an automobile.

  2. Description of the Related Art In recent years, in an automobile, an electric power steering device designed to assist an operator's steering by generating a steering assist force (assist force) with an electric motor and applying the steering assist force to a steering system has been widely used. It has been.

  In such an electric power steering apparatus, for example, an ECU (Electronic Control Unit) that controls the electric motor to rotate in a specific direction (clockwise direction or counterclockwise direction) with respect to the rotation operation of the steering handle. Used, the electric motor is rotated in a specific direction under the control of the ECU, and assist force is generated.

  On the other hand, with the development of electronic devices in recent years, high-performance electronic devices such as navigation systems, televisions, stereos, radios, rear view cameras and the like have been mounted on vehicles.

  These electronic devices react sensitively to various types of noise, and their performance deteriorates, for example, video and audio may be disturbed, and noise countermeasures are becoming important.

  Shield connectors are used as noise countermeasures for highly sensitive equipment such as on-vehicle electrical components.

For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2000-173725), in the shield connectors 10a and 10b, the inner conductor 51 that is not covered by the outer conductor 52 and the vicinity of the inner crimping portion 24 of the inner terminal 20a that is crimped to the tip of the inner conductor 51 A technique for improving the shielding performance by covering the three sides with the covering portion 45 is disclosed.
JP 2000-173725 A

  However, in such noise countermeasures, it is one method to devise the internal structure of the device such as the above-described shielded connector and reduce the influence of noise. It is necessary to take measures.

  As a result of examination by the present inventor, for example, it has been found that the electric power steering apparatus is deeply involved in noise generated in a car radio or the like. This is considered to be because, in the electric power steering apparatus, the drive current of the electric motor is large, the drive frequency is high, and the instantaneous current change during the drive (operation) is large.

  As a result, spike noise is likely to be generated from the electric motor, and the noise is likely to spread around each part of the mechanical mechanism unit in which the electric motor is incorporated. In particular, spreading around the vehicle body greatly affects the car radio and the like. Furthermore, the car radio antenna is often wired along the vehicle body and is easily affected by noise generated in the vehicle body. The noise component diffusion mechanism will be described in detail later with reference to FIG.

  The present invention has been made in view of the above points, and intends to propose an electric power steering apparatus capable of reducing noise with respect to a vehicle body.

  In order to solve such a problem, an electric power steering apparatus according to the present invention is an electric power steering apparatus mounted on a vehicle, wherein a steering assist force corresponding to a steering torque generated on a steering shaft is generated by an electric motor, In the electric power steering apparatus configured to apply the steering assist force to the steering system, the electric power steering apparatus includes a control device that controls the electric motor to rotate in accordance with a steering direction, and the ground terminal of the control device The electric power steering device mounted on the vehicle is connected to a vehicle body near the mounting position of the electric power steering device via a harness.

  According to such a configuration, since the ground terminal of the control device that controls the electric motor is directly connected to the vehicle body portion near the mounting position of the electric power steering device by the harness, noise components generated by the electric motor are spread throughout the vehicle body. Before being transmitted, the noise component can be collected into the control device, and noise can be reduced.

  For example, the electric power steering device includes a device portion to which the electric motor is attached, a frame portion is attached to the vehicle body, the device portion is built in the frame portion, and the control device is The grounding terminal of the control device is connected to the vehicle body portion to which the frame portion is attached.

  For example, the electric power steering device includes a device portion to which the electric motor is attached, a frame portion is attached to the vehicle body portion, and the control device and the device portion are incorporated in the frame portion. The ground terminal of the control device is connected to the frame portion.

  For example, the electric power steering device has a device portion to which the electric motor is attached, a panel member is attached to the vehicle body portion, the device portion is attached to the panel member, and the control device Is disposed on the panel member, and a ground terminal of the control device is connected to the panel member.

  ADVANTAGE OF THE INVENTION According to this invention, the noise with respect to the vehicle body of an electric power steering apparatus can be reduced.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing the relationship between the electric power steering apparatus of the present embodiment and the vehicle body.

  As shown in FIG. 1, the electric power steering device 3 includes an ECU (controller, control device) 3a, an electric motor (electric motor device) 3b, and a mechanical mechanism portion 3c into which these are incorporated. The mechanical mechanism unit 3c is each component (excluding the ECU 3a and the electric motor 3b) constituting the electric power steering device 3, and there is no limitation on the configuration thereof. For example, Japanese Patent Laid-Open No. 2004-129398 (in the publication) An example is disclosed in FIG. 2 and FIG.

  In this manner, the ECU 3a, the electric motor 3b, and the mechanical mechanism unit 3c are appropriately connected (assembled and incorporated). For example, the ECU 3a and the electric motor 3b are connected via a plurality of harnesses 9, and the ECU 3a controls, for example, the electric motor to rotate in a specific direction with respect to a rotation operation (steering direction) of the steering wheel. For example, the electric motor is controlled to rotate in the same direction as or opposite to the steering direction.

  The electric power steering device (mechanical mechanism 3c) 3 is mounted on a vehicle and is assembled to a vehicle body (vehicle BODY, vehicle body) 1, for example. There are various assembling methods, for example, screwing.

  Further, a battery 5 is mounted on the vehicle, and a positive terminal of the battery 5 is connected to various devices to be supplied with power, such as a power terminal of the ECU 3a. The power supply terminal of the ECU 3a is connected to the + terminal of the battery 5 via the power supply harness 7a. Further, the negative terminal of the battery 5 is connected to the vehicle body 1 via the harness 7c and grounded.

  Here, in the present embodiment, the ground terminal (GND terminal) of the ECU 3a is directly connected to the vehicle body 1 via the ground harness 7b. Furthermore, in this case, the connection position of the ground harness 7b on the vehicle body side is in the vicinity of the vehicle body portion on which the electric power steering device 3 itself is mounted. The ground harness 7b and the vehicle body 1 are preferably connected as close as possible to the electric power steering device (its mechanical mechanism portion 3c) 3. Let D be the distance between the electric power steering device (its mechanical mechanism 3c) 3 and the connection position.

  As described above, in the present embodiment, the ground terminal of the ECU 3a is connected to the vicinity of the vehicle body portion on which the electric power steering device 3 itself is mounted via the ground harness 7b, as shown by the arrows in FIG. Before the noise component is transmitted to the entire vehicle body 1, it can be collected by the ECU 3a, and noise can be reduced.

  FIG. 2 is a schematic diagram (comparative diagram) showing the relationship between the electric power steering apparatus and the vehicle body for explaining the effect of the present embodiment. For example, as shown in FIG. 2, when the ground terminal of the ECU 3 a is connected to the negative terminal of the battery 5 via the ground harness 27 b and connected to the vehicle body 1, as shown by the arrow in FIG. The noise component spreads throughout and adversely affects car radios.

  This is because 1) when the electric motor 3b is operated by the control from the ECU 3a, noise components flow from the electric motor 3b to each component (mechanical structure 3c) of the electric power steering device 3 itself. Next, 2) noise components spread from each component of the electric power steering device 3 to the vehicle body 1 and adversely affect the car radio and the like. In particular, the car radio antenna is often wired along the vehicle body 1 and is easily affected by noise generated in the vehicle body 1.

  On the other hand, in the present embodiment, since the ground terminal of the ECU 3a is connected to the vicinity of the vehicle body portion on which the electric power steering device 3 is mounted via the ground harness 7b, noise can be reduced. Moreover, the length of the ground harness 7b can be shortened, and the harness cost can be reduced.

  Next, the connection position of the ground harness 7b on the vehicle body side will be described. As described above, the ground harness 7b and the vehicle body are preferably connected as close as possible to the electric power steering apparatus (its mechanical mechanism 3c) 3.

  Below, the connection form of a ground harness is demonstrated, referring FIGS. 3-5. 3 to 5 are perspective views showing connection examples of the ground harness between the ECU and the vehicle body.

  First, a ground harness connection example in the pinion motor assist system will be described with reference to FIGS. 3 and 4.

  The pinion unit motor assist system is a system that performs electric assist using a motor for a conversion device (herein, “G / BOX” device unit) that converts a handle (rotation) operation into a rack (reciprocation) operation. It is.

  As shown in FIG. 3, the motor 3 b is attached to the G / BOX 33. G / BOX 33 is a part of the mechanical mechanism portion 3c of the electric power steering device. The G / BOX 33 is attached to the lower portion of the vehicle floor panel 30 after being attached to the subframe 35. The vehicle floor panel 30 constitutes a part of the vehicle body 1.

  Here, the ECU 3a is installed, for example, in the vicinity of the attachment portion of the sub-frame (frame portion) 35 of the vehicle floor panel 30, here, on the vehicle floor panel 30 to which the sub-frame 35 is attached, and the ground harness 7b is connected to the ECU 3a. And the vehicle floor panel 30 underneath is connected.

  In this case, the noise component conducted from the motor 3b → G / BOX 33 → the subframe 35 → the vehicle floor panel 30 can be collected in the ECU 3a at a short distance as indicated by the broken arrow in the figure.

  Therefore, it is possible to reduce noise with respect to an electronic device such as an in-vehicle car radio. Moreover, the length of the ground harness 7b can be shortened, and the harness cost can be reduced.

  Although the ground harness 7b is connected to the vehicle floor panel 30 in FIG. 3, it may be connected to the subframe 35 as shown in FIG. In addition, the same code | symbol is attached | subjected to the same site | part as FIG. 3, and the overlapping description is abbreviate | omitted.

  In this case, as shown in FIG. 4, the G / BOX 33 to which the motor 3 b is attached and the ECU 3 a are attached (stored and incorporated) in the recess of the subframe 35. It is attached.

  Here, the ground harness 7b connects, for example, the vicinity of the subframe 35 to which the ECU 3a is attached, here, the upper surface of the subframe 35 and the ECU 3a.

  In this case, the noise component conducted from the motor 3b → G / BOX 33 → the subframe 35 → the vehicle floor panel 30 can be collected in the ECU 3a at a short distance as indicated by the broken arrow in the figure.

  Therefore, it is possible to reduce noise with respect to an electronic device such as an in-vehicle car radio. Moreover, the length of the ground harness 7b can be shortened, and the harness cost can be reduced.

  As described above, various members (for example, a frame, a device, etc.) connected to the vehicle body 1 (vehicle floor panel 30), not directly connected to the vehicle body 1 (vehicle floor panel 30), are provided. You may connect to the various members connected in the form which maintains electroconductivity with 1. Connecting to the vehicle body 1 in a conductive manner means that the various members themselves have conductivity such as metal, or the locations of various members that are electrically connected to the vehicle body 1 through wiring or the like (for example, In the case of having a ground terminal) or the like, this portion is included.

  Next, a connection example of the ground harness in the column motor assist system will be described with reference to FIG.

  This column part motor assist system is a system that performs electric assist using a motor for the column part.

  As shown in FIG. 5, the motor 3 b is attached to the column portion (column ASS′Y) 34. The column portion (device portion) 34 is a part of the mechanical mechanism portion 3c of the electric power steering device. The column portion 34 is attached to the vehicle floor panel member 31. The vehicle floor panel member 31 is a member that is attached to a vehicle floor panel that is a part of the vehicle body 1.

  Here, the ECU 3a is installed, for example, in the vicinity of the attachment portion of the vehicle floor panel member 31, here, in the upper part of the member 31, and the ground harness 7b connects between the ECU 3a and the member 31 therebelow.

  In this case, the noise component conducted from the motor 3b → the column portion 34 → the member 31 can be collected in the ECU 3a at a short distance, as indicated by a broken arrow in the figure.

  Therefore, it is possible to reduce noise with respect to an electronic device such as an in-vehicle car radio. Moreover, the length of the ground harness 7b can be shortened, and the harness cost can be reduced.

  As described above, there are various examples of the connection position of the ground harness 7b on the vehicle body side, but the main point is that the connection is made in the form of maintaining conductivity with both the bodies 1 or the vehicle body 1 in the vicinity of the ECU 3a. The ground harness 7b is connected to various members. In other words, the ground harness 7b is connected to both the bodies 1 in the vicinity of the ECU 3a directly or indirectly (that is, indirectly via another frame, a panel member, or the like).

  In addition to the above-described embodiment, noise emission countermeasures inside the apparatus, such as providing a noise filter in the ECU 3a, may be used in combination.

  The electric power steering apparatus using the electric motor of the above-described embodiment is of a type that applies the assist force generated by the electric motor to the rack shaft or a type that applies the assist force to the steering shaft as described above. The present invention can be widely applied to various electric power steering devices regardless of the mechanism difference.

  The present invention can be widely applied to an electric power steering apparatus for automobiles mounted together with an electronic device such as a radio in addition to an electric power steering apparatus for an automobile.

It is the schematic which shows the relationship between the electric power steering apparatus of this Embodiment, and a vehicle body. It is the schematic (comparison figure) which shows the relationship between the electric power steering apparatus for describing the effect of this Embodiment, and a vehicle body. It is a perspective view which shows the example of a connection of the ground harness between ECU and a vehicle body. It is a perspective view which shows the example of a connection of the ground harness between ECU and a vehicle body. It is a perspective view which shows the example of a connection of the ground harness between ECU and a vehicle body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle body, 3 ... Electric power steering apparatus, 3a ... ECU, 3b ... Electric motor, 3c ... Mechanical mechanism, 5 ... Battery, 7a ... Harness, 7b ... Ground harness, 7c ... Harness, 9 ... Harness, 27b ... Ground Harness, 30 ... Vehicle floor panel, 31 ... Vehicle floor panel member, 33 ... G / BOX, 34 ... Column portion, 35 ... Subframe, D ... Distance

Claims (4)

An electric power steering apparatus mounted on a vehicle, wherein a steering assist force corresponding to a steering torque generated on a steering shaft is generated by an electric motor, and the steering assist force is applied to a steering system. In the device
A control device for controlling the electric motor to rotate in response to a steering direction;
An electric power steering device, wherein a ground terminal of the control device is connected to a vehicle body portion in the vicinity of a mounting position of the electric power steering device mounted on the vehicle via a harness. The electric power steering device has a device portion to which the electric motor is attached,
A frame part is attached to the vehicle body part,
The frame unit incorporates the device unit,
The control device is disposed on a vehicle body portion to which the frame portion is attached,
2. The electric power steering apparatus according to claim 1, wherein the ground terminal of the control device is connected to a vehicle body portion to which the frame portion is attached. The electric power steering device has a device portion to which the electric motor is attached,
A frame part is attached to the vehicle body part,
The frame unit incorporates the control device and the device unit,
The electric power steering apparatus according to claim 1, wherein a ground terminal of the control device is connected to the frame portion. The electric power steering device has a device portion to which the electric motor is attached,
A panel member is attached to the vehicle body,
The device member is attached to the panel member,
The control device is disposed on the panel member;
The electric power steering apparatus according to claim 1, wherein a ground terminal of the control device is connected to the panel member.

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