JP2006224818A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device capable of reducing the feeling of viscosity caused by an excessive increase in damping control component, and preventing a driver from feeling a heavy steering force. <P>SOLUTION: The steering device 1 has a steering shaft 11, and a rotary member 12 is provided on the steering shaft 11. The rotary member 12 has resistance plates 12B-12E, and is stored in a case 13 filled with a viscous fluid 14. The rotary member 12 is rotated coaxially with the steering shaft 11, and when the rotary member is rotated in the case 13 as the steering shaft 11 is rotated, the resistance plates 12B-12E receive viscous resistance from the viscous fluid 14 to give the damping component. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a steering device, and more particularly, to a steering device that improves steering feeling in a vehicle.

  In a steering device used in a vehicle, a damping component is provided to the steering shaft in order to stabilize the system and suppress reverse input vibration. In order to provide such a damping component, in a conventional steering device, for example, a friction mechanism is provided on an end bush of a rack guide, and the damping component is generated by the frictional force of this friction mechanism. Some steering devices using steer-by-wire provide a damping component by providing a damping mechanism as disclosed in JP-A-1-153379.

Further, in a so-called electric power steering apparatus that includes an electric motor that applies a steering assist force, a control device for an electric power steering apparatus disclosed in Japanese Patent Application Laid-Open No. 2002-166844 is provided as one that provides such a damping component. is there. The control device for the electric power steering apparatus includes a damper compensation unit that outputs a damper current corresponding to the vehicle speed, the steering torque, and the steering angular velocity to the electric motor and applies the damper current in a direction opposite to the direction in which the handle rotates. Yes. By applying this damper current to the electric motor, the steering shaft has a damping component to suppress system stabilization and reverse input vibration.
Japanese Patent Laid-Open No. 1-153379 JP 2002-166844 A

  However, the steering device disclosed in Patent Document 1 is provided with a damping mechanism for imparting a damping component. Since this damping mechanism is generally large, if the damping mechanism is provided, there is a problem that the steering device itself becomes large. In particular, in an electric power steering device, it is difficult to provide a large damping mechanism itself.

  In the control device for the electric power steering device disclosed in Patent Document 2, a damper current is applied to the electric motor. However, there is a problem that a large damping control component is required to suppress the vibration, and if the damper current is excessively increased, the steering force may be viscous and heavy.

  Accordingly, an object of the present invention is to provide a steering device that can suitably suppress vibration by providing a damping component to the steering shaft without providing a large damping mechanism. Another object is to provide a steering device that reduces the feeling of viscosity caused by excessively increasing the damping control component and prevents the driver from giving a feeling of heavy steering force.

  A steering apparatus according to the present invention that has solved the above problems includes a steering shaft connected to a steering wheel, and in a steering apparatus that turns steered wheels by rotation of a steering shaft that is rotated by operation of the steering wheel. A resistance plate rotating coaxially is attached to the steering shaft, and the resistance plate is housed in a case filled with a viscous fluid.

  In the steering device according to the present invention, a resistance plate that rotates coaxially with the steering shaft is attached to the steering shaft, and the resistance plate is accommodated in a case filled with a viscous fluid. For this reason, a damping component can be imparted to the steering shaft without providing a large damping mechanism, and vibration can be suitably suppressed. In addition, when applying the damping component, the resistance plate is accommodated in a case filled with a viscous fluid. When the resistance plate is housed in a case filled with viscous fluid, a damping resistance is generated against disturbance when the rotation speed of the resistance plate rotating at the same time as the steering is high, but slow rotation when operating the steering wheel It will not become heavy with respect to the steering. Therefore, it is possible to reduce the feeling of viscosity caused by excessively increasing the damping control component and not to give the driver a feeling of heavy steering force.

  Here, when the steering wheel is in the neutral position, a cutout portion that widens the space between the case and the resistance plate can be formed in a portion of the case where the resistance plate is located.

  Thus, when the steering wheel is in the neutral position, the notch is formed in the portion of the case where the resistance plate is located, so that the steering force is reduced when the steering wheel is in the neutral position. . Therefore, it is possible to prevent the steering force from feeling heavy when the driver starts turning the steering wheel with the intention of turning when the vehicle is traveling straight.

  Moreover, the electric motor which provides a steering assist force is connected to the steering shaft, and a mode in which the resistance plate is attached to the steering side from the position where the electric motor is attached to the steering shaft can also be adopted. .

  In a so-called hydraulic power steering device that applies a steering assist force to the steering by hydraulic pressure, a damping component can be given by the hydraulic portion. Therefore, in a so-called electric power steering device that applies a steering assist force by an electric motor, the hydraulic power steering There is no hydraulic part like the device. For this reason, it becomes effective to provide the damping component by housing the resistance plate attached to the steering shaft in the case filled with the viscous fluid. In particular, since this resistance plate is attached to the steering side of the electric motor, a damping component can be imparted to the vibration generated by the electric motor,

  According to the steering device of the present invention, a damping component can be given to the steering shaft without providing a large damping mechanism. In addition, it is possible to reduce the feeling of viscosity caused by excessively increasing the damping control component and not to give the driver a feeling of heavy steering force.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each embodiment, the same elements are denoted by the same reference numerals as much as possible, and redundant description may be omitted. FIG. 1 is a main part front sectional view of a steering apparatus according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II in FIG.

  As shown in FIG. 1, the steering device 1 according to this embodiment includes a steering shaft 11. A steering wheel (not shown) is attached to one end of the steering shaft 11, and the steering shaft 11 is rotated by operation of the steering wheel. A rotating member 12 that rotates coaxially with the steering shaft 11 is attached to the steering shaft 11.

  As shown in FIG. 2, the rotating member 12 includes a cylindrical member 12A that is press-fitted into the steering shaft 11, and four resistance plates 12B that are spaced apart from each other at equal intervals around the cylindrical member 12A. ~ 12E is attached. Since the cylindrical member 12 </ b> A is press-fitted into the steering shaft 11, the rotating member 12 rotates coaxially with the steering shaft 11.

  When the adjacent first resistor plate 12B and second resistor plate 12C among the four resistor plates 12B to 12E are compared, the width of the first resistor plate 12B is narrower than the width of the second resistor plate 12C. . Furthermore, the width of the third resistance plate 12D disposed at a position facing the first resistance plate 12B is the same as the width of the first resistance plate 12B, and is disposed at a position facing the second resistance plate 12B. The width of the fourth resistance plate 12E is the same as the width of the second resistance plate 12C.

  In addition, the steering device 1 includes a case 13. In the case 13, the steering shaft 11 penetrates, and a rotating member 12 press-fitted into the steering shaft 11 is accommodated. The case 13 is filled with a viscous fluid 14 such as grease or oil. When the rotating member 12 rotates in the case 13 together with the steering shaft 11, the resistance plates 12B to 12E reduce the viscous resistance of the viscous fluid 14. Rotate while receiving. The first and third resistance plates 12B and 12D are smaller than the second and fourth resistance plates 12C and 12E. For this reason, the amount of clearance between the first and third resistance plates 12B and 12D and the inner surface of the case 13 is larger than the amount of clearance between the second and fourth resistance plates 12C and 12E and the inner surface of the case 13. It is also small.

  Further, a seal member 15 such as an oil seal is provided at a portion of the case 13 through which the steering shaft 11 passes. The seal member 15 prevents the viscous fluid 14 from leaking from the gap between the case 13 and the steering shaft 11.

  Further, as shown in FIG. 2, a notch 13 </ b> A is formed at a position on the inner side surface of the case 13 that faces the rotation member 12. When the steering wheel attached to the steering shaft 11 is in the neutral position, the two notch portions 13A are formed in positions corresponding to the two resistance plates 12B and 12D that face each other. The notch 13A widens the space between the resistance plates 12B to 12E and the case 13 at the position where the notch 13A is formed.

  A pinion gear 16 is attached to the lower end portion of the steering shaft 11, and the pinion gear 16 rotates as the steering shaft 11 rotates. Further, the rack teeth 17 </ b> A in the rack bar 17 are meshed with the pinion gear 16. When the pinion gear 16 rotates, the rotational movement is converted into a linear movement by the rack teeth 17A meshing with the pinion gear 16, and the rack bar 17 moves in the left-right direction according to the rotational direction of the pinion gear 16.

  The rack bar 17 is urged in the direction of the pinion gear 16 by a spring 18. Due to the urging force of the spring 18, the rack teeth 17 </ b> A of the rack bar 17 are reliably engaged with the pinion gear 16. These pinion gear 16, rack bar 17, spring 18 and the like constitute a rack and pinion mechanism.

  Wheels are attached to both ends of the rack bar 17 via tie rods, knuckle arms, etc., not shown. When the steering shaft 11 is rotated by the driver operating the steering wheel, this rotational motion is converted into a linear motion via the rack and pinion mechanism, and the wheels are steered.

  The operation of the steering apparatus according to this embodiment having the above-described configuration will be described.

In the steering device 1 according to the present embodiment, when the driver rotates the steering wheel with the intention of turning, the rotation of the steering wheel is transmitted to the steering shaft 11, and the wheels are steered via the rack and pinion mechanism. . Further, in the steering apparatus 1 according to this embodiment, the steering shaft 11 is provided with the rotating member 12, and the rotating member 12 is accommodated in the case 13 filled with the viscous fluid 14. Has been. As described above, when the rotating member 12 rotates in the case 13 filled with the viscous fluid 14, the resistance plates 12B to 12E in the rotating member 12 generate viscous resistance in the rotation direction proportional to the rotation speed. . However, the magnitude of this viscous resistance varies depending on the rotational speed (rotational angular speed) of the rotating member 12 attached to the steering shaft 11.

  As shown by the solid line in FIG. 3, the rotational angular velocity of the steering shaft 11 is not large, and with slow steering, the pressure of the viscous fluid remains static, so that almost no damping resistance force due to viscous resistance is generated. For this reason, the steering force is not increased, and a smooth steering feeling in which slight vibrations are suppressed can be obtained. In FIG. 3, the amount of sliding Coulomb friction force generated outside the case 13 is indicated by a broken line.

  On the other hand, the viscous resistance generated by the viscous fluid 14 increases as the rotational angular velocity increases. In the reverse input from the wheel, the rotational angular velocity is increased, so that the viscous resistance from the viscous fluid 14 acts on the rotating member 12 and the fine vibration input from the wheel can be suitably suppressed.

  Such adjustment of the magnitude of the viscous resistance can be adjusted by the amount of gap between the resistance plates 12B to 12E and the case 13, the size of the resistance plates 12B to 12E, the viscosity of the viscous fluid, and the like.

  Further, in the steering device 1 according to the present embodiment, when the steering wheel is in the neutral position and the wheel faces in the direction in which the vehicle goes straight, the notch is formed on the inner surface side of the case 13 where the resistance plates 12B and 12D are located. Part 13A is formed. Therefore, when the driver intends to turn and starts to rotate the steering wheel, the attenuation can be reduced, and a feeling of heavy steering force can be suitably prevented.

  Moreover, in the said embodiment, when the steering shaft 11 makes one turn, it will return to the same position as the case where a steering wheel becomes neutral. When the steering wheel returns to the same position as the neutral position, the first and third resistance plates 12B and 12D are arranged again at positions corresponding to the mist notches 13A in the case 13 and fluctuate so as to reduce the resistance. Stability of steering force is slightly lowered. However. Such fluctuations in resistance are caused by a large steering angle range. When the steering device is an electric power steering device that applies a steering assist force by an electric motor, the steering assist force is more effective than the resistance variation. Is much larger. Therefore, the steering force is hardly lowered due to the resistance variation.

  In addition to the first and third resistance plates 12B and 12D, the rotating member 12 in the steering device 1 according to the present embodiment includes the second and fourth resistance plates 12C at positions having a phase difference of about 90 degrees. , 12E are provided. Since the second and fourth resistance plates 12C and 12E are provided, the resistance varies when the resistance plates 12B to 12E pass through the positions corresponding to the notches 13A. Since the magnitude and phase of the resistance variation due to each resistance plate are different, the variation can be reduced.

  In particular, the second and fourth resistance plates 12C and 12E are made larger than the first and third resistance plates 12B and 12D. For this reason, since the magnitude | size and phase of resistance fluctuation by each resistance plate 12B-12E differ, resistance fluctuation | variation can be reduced. For example, under the condition that the rotation speed of the rotating member 12 is constant, the resistance by the first and third resistance plates 12B and 12D shows the change shown by the broken line L1 in FIG. 4, and the second and fourth resistance plates 12C and 12E. It is assumed that the resistance due to shows the change indicated by the broken line L2 in FIG. In this case, the resistance change by each of the resistance plates 12B to 12E becomes like a broken line L3 shown in FIG. As can be seen from the broken line L3 in FIG. 4, the change in resistance when the four resistance plates 12B to 12E are used is smaller than the change in resistance when only the first and third resistance plates 12B and 12D are provided. It has become. As described above, by providing the second and fourth resistance plates 12C and 12E, it is possible to reduce the fluctuation of the resistance, thereby suppressing the increase or decrease of the steering force due to the fluctuation of the resistance.

  Next, a second embodiment of the present invention will be described. In this embodiment, compared with said 1st embodiment, the aspect of the case which accommodates the rotation member 12 mainly differs.

  In the steering apparatus according to the present embodiment, as shown in FIGS. 5 and 6, the case 20 is not formed with a notch portion on the inner surface, and a notch portion 21 is formed on the upper surface and the lower surface. Yes. This is mainly different from the first embodiment.

  The notch 21 is formed at a position where the two opposing resistance plates 12B and 12D in the rotating member 12 correspond when the steering wheel is in the neutral position. In the example shown in FIGS. 5 and 6, a state in which the steering wheel is rotated 90 degrees is illustrated, and the second and fourth resistance plates are located at positions corresponding to the positions where the notches 21 are formed. 12C and 12E are arranged. The case 20 is filled with a viscous fluid as in the first embodiment. About another point, it has the structure similar to said 1st embodiment.

  Also in the steering device according to the present embodiment having the above-described configuration, the rotational angular velocity of the steering shaft 11 is not large as in the first embodiment, and the pressure of the viscous fluid remains static when the steering is slow. Therefore, almost no damping resistance force due to viscous resistance is generated. For this reason, the steering force is not increased, and a smooth steering feeling in which slight vibrations are suppressed can be obtained. On the other hand, the viscous resistance generated by the viscous fluid 14 increases as the rotational angular velocity increases. In the reverse input from the wheel, the rotational angular velocity is increased, so that the viscous resistance from the viscous fluid 14 acts on the rotating member 12 and the fine vibration input from the wheel can be suitably suppressed.

  Next, a third embodiment of the present invention will be described. FIG. 8 is an electric power steering apparatus provided with an electric motor for applying a steering assist force to a steering shaft according to a third embodiment of the present invention. The steering shaft 11 in this electric power steering apparatus is provided with the rotating member 12, the case 13, the seal member 15 and the like. The rotating member 12 is housed in a case 13 and the case 13 is filled with a viscous fluid.

  In addition, the electric power steering apparatus according to the present embodiment has an electric motor 30. The electric motor 30 is connected to the steering shaft 11 through a gear mechanism (not shown), and the steering shaft is appropriately selected according to the steering torque applied by the driver through the steering wheel, the rotation angle of the steering shaft 11, the vehicle speed, and the like. A steering assist force is applied to 11. Further, the rotating member 12, the case 13, and the seal member 15 are provided on the steering wheel side with respect to the electric motor 30, and the resistance plate is also provided on the steering wheel side with respect to the electric motor 30. About another structure, it has the structure similar to said 1st embodiment.

  In the electric power steering apparatus according to the present embodiment having the above-described configuration, the rotational angular velocity of the steering shaft 11 is not large as in the first embodiment, and the pressure of the viscous fluid remains static during slow steering. Therefore, almost no damping resistance force due to viscous resistance is generated. For this reason, the steering force is not increased, and a smooth steering feeling in which slight vibrations are suppressed can be obtained. On the other hand, the viscous resistance generated by the viscous fluid 14 increases as the rotational angular velocity increases. In the reverse input from the wheel, the rotational angular velocity is increased, so that the viscous resistance from the viscous fluid 14 acts on the rotating member 12 and the fine vibration input from the wheel can be suitably suppressed.

  Further, in the electric power steering apparatus according to the present embodiment, vibration is generated by driving the electric motor 30, and the vibration is transmitted to the steering wheel. In this regard, in the electric power steering apparatus according to the present embodiment, the rotating member 12 accommodated in the case 13 is provided between the electric motor 30 and the steering wheel. For this reason, the vibration generated by the electric motor “30 can be suitably damped, and the vibration transmitted to the steering wheel can be suppressed.

The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. For example, in each said embodiment, although the notch part is formed in the case which accommodates a rotation member, it can be set as the aspect which does not form this notch part. Moreover, although the electric power steering device is targeted in the third embodiment, it can also be used for a hydraulic power steering device that applies a steering assist force by hydraulic pressure.

It is a principal part front sectional view of the steering device concerning a first embodiment. It is the II-II sectional view taken on the line of FIG. It is a graph which shows the relationship between the rotational angular velocity of a steering shaft, and resistance (viscosity resistance and Coulomb friction force). It is a graph which shows the relationship between the rotation angle of a steering shaft at the time of rotating a steering shaft at a fixed angular velocity, and resistance. It is a principal part sectional drawing of the steering device which concerns on 2nd embodiment. It is a principal part expanded front sectional view of FIG. It is the VII-VII sectional view taken on the line of FIG. It is a side view of the steering device (electric power steering device) concerning a third embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Steering device, 11 ... Steering shaft, 12 ... Rotating member, 12A ... Cylindrical member, 12B-12E ... Resistance plate, 13 ... Case, 13A ... Notch part, 14 ... Viscous fluid, 15 ... Seal member, 16 ... Pinion Gear, 17 ... rack bar, 17A ... rack teeth, 18 ... spring, 30 ... electric motor.

Claims (3)

In a steering apparatus comprising a steering shaft connected to a steering wheel and turning steered wheels by rotation of the steering shaft rotated by operation of the steering wheel,
A resistance plate that rotates coaxially with the steering shaft is attached to the steering shaft,
The steering device according to claim 1, wherein the resistance plate is accommodated in a case filled with a viscous fluid.   The notch part which widens between the said case and the said resistance plate is formed in the site | part in which the said resistance plate is located in the said case when the said steering wheel becomes a neutral position. Steering device. An electric motor for applying a steering assist force is connected to the steering shaft;
The steering device according to claim 1 or 2, wherein the resistance plate is attached to the steering wheel side of the steering shaft from a position where the electric motor is attached.

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