JP2007186209A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device capable of reducing the retraction of a steering column when a predetermined high load is applied to a front vehicle body by utilizing a column assist system. <P>SOLUTION: The steering column 16 is supported on an instrument panel reinforcement 18 so as to be tilt-operable. A motor 28 arranged on the front end side of the steering column 16 is arranged longitudinally on the front side of an instrument panel reinforcement 18. When the steering column 16 is displaced substantially backward of the vehicle when the predetermined high load is applied to the front vehicle body, the motor 28 is interfered with the instrument panel reinforcement 18. Displacement substantially backward of the vehicle of the steering column 16 is regulated and its retraction is reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a column assist type electric power steering apparatus.

  The power steering device includes a hydraulic power steering device that obtains assist thrust by converting part of engine power into hydraulic pressure, and an electric power steering device that obtains assist thrust by driving and rotating a motor using electric power. There is. Japanese Patent Laid-Open No. 6-40345 discloses an example of the latter electric power steering apparatus, and will be briefly described below with reference to FIG.

  As shown in this figure, the electric power steering apparatus 100 disclosed in the above publication is a so-called column assist system in which an assisting motor 102 is arranged on the steering column 104 side.

  Specifically, in the first housing 106 disposed coaxially with the column tube, there are an input shaft on the steering input side, an output shaft 108 on the steering output side, and these input shaft and output shaft. A torsion bar 110 that couples to the output shaft 108 and a worm wheel 112 fixed to the outer periphery of the output shaft 108 are accommodated. The second housing 114 extended in a direction perpendicular to the axis of the first housing 106 includes a motor 102 and an electromagnetic clutch 118 whose operation is controlled by the control unit 116, and an axial core portion of the clutch 118. A spline-fitted worm shaft 120 is accommodated.

According to the above configuration, when the driver steers the steering wheel, the steering force at that time is input to the input shaft via the steering main shaft. Since the input shaft is connected to the output shaft 108 via the torsion bar 110, when the input shaft rotates, the output shaft 108 also rotates. At this time, the torsion bar 110 is twisted, and the twist is detected by the torque sensor and output to the control unit 116. The control unit 116 determines whether or not the operating condition for assisting is met based on the detection signal from the torque sensor, the detection signal from the speed sensor, and the like. Is supplied with a predetermined current. For this reason, the driving force of the motor 102 is transmitted to the worm shaft 120 via the clutch 118, and further transmitted from the worm shaft 120 to the worm wheel 112 and the output shaft 108. In this process, a deceleration action and a torque increase action are obtained, and the steering force of the driver is assisted.
JP-A-6-40345

  However, in the case of the electric power steering apparatus 100 having the above-described configuration, there is no room for improvement in this respect because no safety measure has been taken, focusing on the column assist method.

  That is, when a predetermined high load is applied to the front part of the vehicle body, the steering column may move backward substantially toward the vehicle rear side. If the amount of backward movement of the steering column at this time can be reduced by utilizing the column assist method, a column-assist type electric power steering device with high added value can be obtained. However, in the electric power steering apparatus 100 configured as described above, since there is an emphasis on improving the maintainability of the motor 102, such safety measures have not been taken.

  In consideration of the above facts, the present invention provides an electric power steering device that can reduce the amount of reverse of the steering column when a predetermined high load is applied to the front of the vehicle body by utilizing the column assist method. The purpose is to obtain.

  The present invention according to claim 1 includes a steering column supported by a vehicle body side component member so as to be capable of tilting operation, and a steering force assisting motor integrally disposed on the steering column side. A column assist type electric power steering device, wherein the motor is arranged to be separated from the front side of the vehicle so as to be tiltable with respect to the vehicle body side component, and when a predetermined high load is applied to the front of the vehicle body In accordance with the displacement of the steering column substantially toward the rear of the vehicle, the vehicle body side structural member or the vehicle body side interference member provided on the vehicle body side structural member and the motor or the motor side interference member provided on the motor are mutually Due to the interference, the displacement of the steering column to the substantially rear side of the vehicle is restricted.

  The electric power steering apparatus according to a second aspect of the present invention is the electric power steering apparatus according to the first aspect of the invention, wherein the vehicle body side component member is a high-strength instrument panel reinforcement arranged with the vehicle width direction as a longitudinal direction. It is characterized by that.

  According to a third aspect of the present invention, there is provided the electric power steering apparatus according to the first or second aspect of the invention, wherein the motor is arranged in a vertical state with respect to the steering column. Yes.

  The electric power steering apparatus according to the first aspect of the present invention is a column assist system in which a steering force assisting motor is integrally disposed on a steering column side supported by a vehicle body side component member so as to be tiltable. Assuming that there is, the following actions can be obtained under this assumption.

  That is, when a predetermined high load is applied to the front part of the vehicle body, the steering column tends to be displaced substantially rearward of the vehicle. Since the motor is provided integrally on the steering column side and is disposed so as to be tiltable with respect to the vehicle body side component member so as to be substantially spaced forward of the vehicle, the steering column is displaced substantially backward of the vehicle. In this case, the motor is also displaced toward the vehicle body side component.

  At this time, according to the present invention, the vehicle body side structural member or the vehicle body side interference member provided on the vehicle body side structural member and the motor or the motor side interference member provided on the motor interfere with each other, thereby steering. Displacement of the column to the substantially vehicle rear side is restricted.

  In addition, according to the present invention, since the motor is disposed substantially away from the vehicle body side structural member toward the front side of the vehicle, a tilt operation is possible.

  According to the second aspect of the present invention, since the vehicle body side component member is an instrument panel reinforcement arranged with the vehicle width direction as a longitudinal direction, a predetermined high load acts on the front portion of the vehicle body so that the steering column is substantially a vehicle. When displaced rearward, the motor interferes with instrument panel reinforcement. Since the instrument panel reinforcement has high strength, the interference with the motor effectively restricts the displacement of the steering column toward the substantially rear side of the vehicle.

  According to the third aspect of the present invention, since the motor is arranged in a vertical state with respect to the steering column, the axis of the steering column is located closer to the center of gravity of the motor than in the case where the motor is arranged in a horizontal state. The amount of offset in the vehicle width direction becomes smaller.

  As described above, in the electric power steering apparatus according to the first aspect of the present invention, the motor is disposed substantially on the front side of the vehicle so as to be tiltable with respect to the vehicle body side component member, and to the front of the vehicle body. When a predetermined high load action is applied, the vehicle body side component member or the vehicle body side interference member provided on the vehicle body side component member and the motor or the motor provided on the motor in accordance with the displacement of the steering column to the substantially vehicle rear side By interfering with the side interference member, the displacement of the steering column to the substantially rear side of the vehicle is restricted, so that the steering column is substantially rearward of the steering column when a predetermined high load is applied to the front of the vehicle body. As a result, there is an excellent effect that it is possible to reduce the amount of backward movement of the steering column when a predetermined high load is applied to the front part of the vehicle body. That.

  In addition, according to the present invention, since the motor is disposed substantially away from the vehicle body side structural member toward the front side of the vehicle, a tilt operation is possible.

  According to a second aspect of the present invention, in the electric power steering device according to the first aspect, the vehicle body side component member is a high-strength instrument panel reinforcement arranged with the vehicle width direction as a longitudinal direction. This has an excellent effect that the displacement of the steering column to the substantially vehicle rear side can be effectively restricted when a predetermined high load is applied to the vehicle.

  The electric power steering apparatus according to the third aspect of the present invention is the electric power steering apparatus according to the first or second aspect of the invention, wherein the motor is arranged in a vertical state with respect to the steering column, so that the motor is in a horizontal state. Compared to the arrangement, the offset amount in the vehicle width direction from the axis of the steering column to the center of gravity of the motor is reduced, and as a result, it has an excellent effect of being advantageous for vertical steering vibration.

  Hereinafter, an electric power steering apparatus 10 according to an embodiment of the present invention will be described with reference to FIGS.

  1 shows a side view of the assembled state of the electric power steering device 10, and FIG. 2 shows a plan view of the assembled state of the electric power steering device 10. 3 shows a rear view of the assembled state of the electric power steering apparatus 10. In these drawings, an arrow FR appropriately shown indicates the vehicle front side, an arrow UP indicates the vehicle upper side, and an arrow IN indicates the vehicle interior side.

  As shown in these drawings, the electric power steering apparatus 10 includes a cylindrical column tube 12, and a steering main shaft 14 rotatably supported on a shaft portion of the column tube 12 by a bearing (not shown). A steering column 16 is provided. A male screw is formed on the outer peripheral surface of the rear end portion of the steering main shaft 14, and a steering wheel (not shown) steered by a driver is fixed to the male screw by a lock nut. Further, the front end portion of the steering main shaft 14 is connected to the steering gear box via an intermediate shaft (not shown). Thus, the steering force applied to the steering wheel is transmitted to the steering gear box via the steering main shaft 14 and the intermediate shaft.

  The steering column 16 described above is supported by a steering support 20 fixed to an instrument panel reinforcement 18 as a “vehicle body side component”. The instrument panel reinforcement 18 is a high-strength pipe-like member that is disposed approximately on the vehicle front side of an instrument panel (not shown) with the vehicle width direction as the longitudinal direction. The steering support 20 is a high-strength member fixed to the lower part of the peripheral surface of the instrument panel reinforcement 18 in a forwardly inclined state.

  The steering column 16 is attached so as to be able to be tilted via a lower bracket portion 22 and an upper bracket portion 24 that are disposed at two front and rear positions on the front end side and the rear end side of the steering support 20. The detailed structure of the lower bracket portion 22 and the upper bracket portion 24 will not be described, but generally, the bracket on the column side is fitted to the bracket on the support side and connected to each other by bolt fastening. Yes. In FIG. 1, the symbol A marked on the lower bracket portion 22 represents the axial center of a tilt hinge bolt (not shown), and the symbol B marked on the upper bracket portion 24 is the pivot center of a tilt lever not shown. The axis center of the tilt lock bolt is shown.

  As described above, the worm wheel 26 arranged coaxially with respect to the steering main shaft 14 is disposed on the front end side of the steering column 16 supported by the steering support 20. The worm wheel 26 is arranged concentrically on the outer peripheral portion of the output shaft connected via the torsion bar with the input shaft rotating together with the steering main shaft 14.

  A steering force assisting motor 28 is disposed at a position adjacent to the worm wheel 26 in the steering column 16. The motor 28 includes a motor body 30 and an electromagnetic clutch 32 whose operation is controlled by a control unit (not shown). Further, a worm shaft 34 that meshes with the worm wheel 26 is disposed on the shaft core portion of the clutch 32. A speed sensor for detecting the vehicle speed and a torque sensor for detecting torsion of the torsion bar are connected to the input side of the control unit.

  Further, the motor 28 described above is arranged in a vertically placed state with respect to the steering column 16. That is, as shown in FIG. 3, the axis P of the motor 28 is arranged at a predetermined angle θ with respect to the axis Q of the steering column 16 and is arranged not in the vehicle width direction but in the vehicle vertical direction. ing.

In the above configuration, the worm shaft 34 and the worm wheel 26 are elements that are grasped as “deceleration means” in a broad sense.
Next, the operation and effect of this embodiment will be described.

  First, the schematic operation of the electric power steering apparatus 10 according to the present embodiment will be briefly described.

  When the driver steers the steering wheel, the steering force at that time is input to the input shaft via the steering main shaft 14. Since the input shaft is connected to the output shaft via a torsion bar, when the input shaft rotates, the output shaft also rotates. At this time, the torsion bar is twisted, and the twist is detected by the torque sensor and output to the control unit. The control unit determines whether or not the operating conditions for assisting are met based on the detection signal from the torque sensor, the detection signal from the speed sensor, and the like. A predetermined current is supplied to the electromagnetic clutch 32. As a result, the driving force of the motor main body 30 can be transmitted to the worm shaft 34 via the clutch 32. For this reason, the driving force of the motor main body 30 is transmitted to the worm shaft 34 via the clutch 32, and the worm shaft 34 is rotated about its axis. When the worm shaft 34 is rotated, the worm wheel 26 meshing with the worm shaft 34 is rotated, and the output shaft integrated with the worm wheel 26 is further rotated. In this process, a deceleration operation and a torque increase operation are obtained, and the steering force of the driver is assisted.

  The above is the schematic operation of the electric power steering apparatus 10 according to the present embodiment. As can be seen from the above description, the electric power steering apparatus 10 according to the present embodiment has a steering force assist motor on the steering column 16 side. This is a column assist system in which 28 is integrally arranged, and the following operations and effects are obtained on the premise of this point.

  That is, when a predetermined high load is applied to the front portion of the vehicle body, the steering column 16 tends to be displaced to the rear side of the vehicle. Since the motor 28 is provided integrally on the steering column 16 side and is spaced apart from the instrument panel reinforcement 18 substantially toward the front side of the vehicle, the motor 28 is displaced substantially toward the rear side of the vehicle. The motor 28 is also displaced toward the instrument panel reinforcement 18 side.

  Here, in the present embodiment, the motor 28 is arranged in a vertically placed state with respect to the steering column 16, so that the motor 28 comes into contact with the instrument panel reinforcement 18 when the steering column 16 is displaced substantially rearward of the vehicle. Due to the mutual interference between the motor 28 and the instrument panel reinforcement 18, the displacement of the steering column 16 toward the substantially rear side of the vehicle is restricted. As a result, according to the present embodiment, it is possible to reduce the reverse amount of the steering column 16 when a predetermined high load is applied to the front portion of the vehicle body.

  Further, in the present embodiment, since the motor 28 is brought into contact with the high-strength instrument panel reinforcement 18 arranged with the vehicle width direction as the longitudinal direction, the steering column at the time of a predetermined high load acting on the front of the vehicle body The displacement of 16 toward the rear side of the vehicle is effectively restricted. As a result, according to the present embodiment, it is possible to more effectively reduce the amount of retraction of the steering column 16 when a predetermined high load is applied to the front portion of the vehicle body.

  Furthermore, since the instrument panel reinforcement 18 is an existing member, the number of parts does not increase even when compared with the conventional structure. For this reason, there is also an advantage that the vehicle body structure and the like can be prevented from becoming complicated.

  Further, in the present embodiment, as shown in FIG. 2, the motor 28 is arranged in a vertically placed state with respect to the steering column 16, so that compared with the case where the motor is placed in a horizontally placed state with respect to the steering column, The offset amount W in the vehicle width direction from the axis Q of the steering column 16 to the center of gravity G of the motor 28 is reduced. That is, the position where the Mass (motor 28) is added to the steering column 16 is a position where the lateral moment length is shortened. For this reason, according to this embodiment, it is advantageous for longitudinal steering vibration.

  Supplementally, the steering vibration is a shake that is mainly a vibration in the vertical direction of the vehicle (shake is a phenomenon in which the steering vibrates up and down at a specific vehicle speed when traveling at high speed. If there is balance etc., tire vibration will occur during driving and will be transmitted to the body and engine.When the body and engine resonate due to this vibration, the vibration will be further increased, causing the steering to vibrate and shake. This is a problem, and this embodiment is advantageous to the shake.

  In the present embodiment, a configuration is adopted in which the motor 28 is arranged vertically with respect to the steering column 16 so that the motor 28 contacts the instrument panel reinforcement 18 when a predetermined high load is applied to the front of the vehicle body. However, the present invention is not limited to this, and various configurations can be employed.

  For example, a bracket extended toward the motor 28 at a predetermined position in the instrument panel reinforcement 18 (the bracket corresponds to the “vehicle body side interference member” in claim 1) is disposed, and the motor 28 is applied to the bracket. You may take the structure to contact.

  Conversely, a bracket (the bracket corresponds to the “motor-side interference member” described in claim 1) extending from the motor 28 toward the instrument panel reinforcement 18 is disposed, and the bracket is applied to the instrument panel reinforcement 18. You may take the structure to contact.

  Furthermore, the bracket may be extended from both the instrument panel reinforcement 18 and the motor 28, and the brackets may be configured to interfere with each other.

  As can be seen from the above examples, in the present embodiment, the motor 28 is placed vertically with respect to the steering column 16 in order to bring the motor 28 into contact with the instrument panel reinforcement 18 when a predetermined high load is applied to the front portion of the vehicle body. However, in the relationship with the present invention described in claim 1, a configuration in which the motor is disposed in a lateral state with respect to the steering column is also included. Thus, even if the motor is arranged horizontally with respect to the steering column, the same effect as this embodiment can be obtained by extending the bracket that can interfere with the horizontally installed motor from the instrument panel reinforcement 18. In addition, if the bracket capable of interfering with the instrument panel reinforcement 18 is extended from the horizontally placed motor, the same effect as in the present embodiment can be obtained.

  Further, not only a function of reducing the amount of retraction of the steering column 16 but also an energy absorbing function may be added to the bracket described above. For example, in the first example, when a weak portion such as a plurality of holes, slits, beads, or a thin portion is set on the bracket extending from the instrument panel reinforcement 18 to the motor 28 side, the motor 28 comes into contact with the bracket. The bracket may be buckled substantially in the vehicle longitudinal direction. In this case, since the force (energy) for retreating the steering column 16 is absorbed, the amount of retraction of the steering column 16 can be reduced, and the input load to the instrument panel reinforcement 18 can also be reduced.

  Furthermore, in the present embodiment, the existing instrument panel reinforcement 18 is used as the vehicle body-side component member. However, in the relationship with the present invention according to claim 1, together with the steering column 16 when a predetermined high load is applied to the vehicle body front portion. Any vehicle body-side structural member can be used as long as it can interfere with the motor 28 that is displaced substantially toward the rear of the vehicle and has a strength that can restrict the displacement of the steering column 16 toward the substantial rear of the vehicle. It is. For example, a steering support or the like is an available vehicle body side component. Specifically, a configuration in which an overhanging portion capable of interfering with the motor 28 is integrally provided on the steering support is conceivable. In this case, the steering support corresponds to the “vehicle body side component” in the present invention.

It is a side view of the assembly state of the electric power steering device according to the present embodiment. FIG. 2 is a plan view of an assembled state of the electric power steering device shown in FIG. 1. FIG. 2 is a rear view of the assembled state of the electric power steering device shown in FIG. 1. It is a longitudinal cross-sectional view centering on the motor of the electric power steering apparatus which concerns on a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electric power steering apparatus 16 Steering column 18 Instrument panel reinforcement (vehicle body side structural member)
20 Steering support 28 Motor

Claims (3)

A steering column supported on the vehicle body side component so as to be tiltable,
A steering force assisting motor integrally disposed on the steering column side;
A column assist type electric power steering device comprising:
The motor is disposed so as to be tiltable with respect to the vehicle body-side component member so as to be substantially separated from the front side of the vehicle,
When a predetermined high load is applied to the front portion of the vehicle body, the vehicle body side structural member or the vehicle body side interference member provided on the vehicle body side structural member and the motor or the motor are moved along with the displacement of the steering column substantially toward the vehicle rear side. Displacement of the steering column to the substantially rear side of the vehicle is restricted by the interference with the provided motor side interference member.
An electric power steering device. The vehicle body side component member is a high-strength instrument panel reinforcement arranged with the vehicle width direction as a longitudinal direction.
The electric power steering apparatus according to claim 1. The motor is arranged in a vertical position with respect to the steering column,
The electric power steering apparatus according to claim 1 or 2, characterized in that

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