JP3198928B2 - Vehicle steering control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering control device for a vehicle such as an automobile, and more particularly to an assist mechanism for obtaining a steering assist force and a steering reaction force for giving a reaction force to the steering force. The present invention relates to a vehicle steering control device having a mechanism.

[0002]

2. Description of the Related Art As a steering control device (for example, a hydraulic power steering device) for a vehicle such as an automobile, a power steering device having a hydraulic control valve is known (for example, Japanese Utility Model Laid-Open No. 2-117969). ).

[0003] In the power steering apparatus disclosed in this publication, the hydraulic control valve is a so-called rotary valve having a valve shaft and a valve body, and the hydraulic pressure is supplied by the relative displacement between the valve shaft and the valve body. Discharge control can be performed. Further, this hydraulic control valve is provided with a hydraulic reaction force mechanism for giving a reaction force to the steering force. The hydraulic reaction force mechanism includes a piston that engages with a valve shaft of a hydraulic control valve. The force by which the piston presses the valve shaft by hydraulic pressure acts as a steering reaction force, whereby a predetermined reaction force is applied to the steering force of the steering mechanism, and a stable steering feeling is obtained.

Further, an annular groove is formed on the outer periphery of the intermediate portion of each piston, and an O-ring is fitted therein.
These constitute a frictional force applying means. Thus, the configuration is such that hysteresis occurs in the characteristic diagram of the steering torque-hydraulic characteristic. This allows
The feeling of response at the start of the steering operation (at the time of turning) is improved, and the steering holding force at the time of steering wheel steering is reduced, so that a better steering feeling can be obtained.

However, in the power steering apparatus using such a hydraulic control valve, as described above, the frictional force applying means is provided on the outer periphery of the piston to provide hysteresis to the steering characteristics, and the O-ring or the O-ring is used. Since it is necessary to provide an annular groove for accommodating, there is a disadvantage that the configuration is complicated and the number of parts is increased.

[0006]

SUMMARY OF THE INVENTION In view of the above, the present invention provides a vehicle steering control device which can provide a large hysteresis in steering torque-hydraulic characteristics with a simple structure without increasing the number of parts. The purpose is to get.

[0007]

According to a first aspect of the present invention, there is provided a steering control apparatus for a vehicle, comprising: a steering mechanism for mechanically connecting a steering wheel and a steering wheel; and a valve shaft and a valve body. An assist mechanism having a hydraulic control valve disposed on the way, and controlling a hydraulic fluid from a hydraulic pressure source by a relative displacement between the valve shaft and the valve body of the hydraulic control valve to obtain a steering assist force according to a steering torque; A lever provided on the valve shaft, and provided in connection with a hydraulic control valve of the assist mechanism in the middle of the steering mechanism, and urged by an oil liquid from a hydraulic source.
A steering reaction force mechanism for applying a steering reaction force to the valve shaft via the lever portion and having at least a pair of plungers whose reaction directions are opposed to each other, and controlling a reaction force applied to a steering force. in the steering control apparatus for a vehicle, the moving direction of the pair of plungers, said
It is characterized by being provided at a predetermined angle with respect to an axis perpendicular to the lever portion .

In the vehicle steering control device according to the first aspect, when the steering wheel is operated, the steered wheels are steered by the steering mechanism and the assist mechanism is operated in response thereto (the valve shaft of the hydraulic control valve). And the valve body is relatively displaced), thereby controlling the supply and discharge of the oil pressure from the hydraulic pressure source, and applying a steering assist force according to the steering torque. Further, the steering reaction force mechanism operates in conjunction with the hydraulic control valve of the assist mechanism, and hydraulic pressure is supplied to the pair of plungers to apply a predetermined reaction force to the steering force of the steering mechanism, thereby providing a stable steering feeling. can get.

In this case, in the steering reaction force mechanism, the valve
The lever of the shaft pushes the plunger. here
In, the moving direction of the pair of plungers to the axis perpendicular to the lever portion is provided with a predetermined angle inclined, in other words, the valve shaft at the time of the hydraulic control valve operating les
Since the direction of input from the bar portion to the plunger and the actual direction of movement of the plunger differ (incline), sliding frictional resistance is generated on the outer peripheral portion of the plunger with the movement of the plunger. As a result, hysteresis is generated in the steering torque-hydraulic characteristic, the feeling of response at the start of steering operation (at the time of turning) is improved, and the steering force at the time of steering wheel steering is reduced, so that a good steering feeling is obtained. Obtainable.

In addition, since the plunger can be simply provided with the moving direction inclined at a predetermined angle with respect to the axis perpendicular to the lever , the hysteresis in the steering torque-hydraulic characteristic can be obtained. Since it is not necessary to provide an O-ring or an annular groove for accommodating the O-ring in the plunger in order to obtain the hysteresis characteristic as in the related art, the configuration is simplified and the number of parts does not increase.

Further, if the inclination state of the plunger is changed, the sliding friction resistance generated on the outer peripheral portion of the plunger is changed, and the hysteresis characteristic can be adjusted.

As described above, in the vehicle steering control device according to the first aspect, a large hysteresis can be provided in the steering torque-hydraulic characteristic with a simple structure without increasing the number of parts.

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

FIG. 1 shows the overall configuration of a vehicle steering control device according to a first embodiment of the present invention.

The vehicle steering control device includes a control valve 10. The control valve 10 has a cylindrical valve housing 12, and a valve body 14 is disposed in the valve housing 12 so as to be relatively rotatable. The valve body 14 has a cylindrical shape, and is connected to a pinion shaft 15 (output shaft) via a pin 17 so as to be integrally rotatable.

The valve shaft 1 is mounted on the valve body 14.
6 are fitted so as to be relatively rotatable. The valve shaft 16 is connected to an input shaft (not shown).

Further, a torsion bar 18 is arranged at the axis of the valve shaft 16. One end of the torsion bar 18 is connected to the valve shaft 16 (input shaft), and the other end is connected to the pinion shaft 15. That is, the valve shaft 16 (input shaft) is connected to the pinion shaft 15 via the torsion bar 18, and is connected to the pinion shaft 15 when the torsion bar 18 is twisted by the turning operation of the steering wheel. A relative angular displacement is generated between the valve body 14 and the valve shaft 16 connected to the input shaft.

The outer circumferential surface of the valve body 14 has an annular groove 2
0A, 20B and 20C are formed at predetermined intervals in the axial direction, the central annular groove 20B is connected to a hydraulic pump (not shown) via a hydraulic circuit, and the upper annular groove 20A is a power cylinder (not shown). For example, the lower annular groove 20C in the axial direction is connected to, for example, a left oil chamber of the power cylinder.

As shown in FIG. 3, on the inner peripheral surface of the valve body 14, a land portion 22 and a concave groove 24 extending in the axial direction are formed.
They are formed alternately along the circumferential direction. A pressure oil hole 26 for introducing hydraulic pressure from a hydraulic pump into the control valve 10 through a central annular groove 20 </ b> B is formed through the valve body 14 in the radial direction of the land 22. Further, a suction / discharge oil hole 28 communicating with one annular groove 20A for sucking / discharging oil pressure in, for example, a right oil chamber of the power cylinder is formed in the concave groove 24, and the other oil suction / discharge oil pump, for example, in the left oil chamber of the power cylinder An oil suction / discharge hole 30 communicating with the annular groove 20 </ b> C is formed in the concave groove 24.

On the outer peripheral surface of the valve shaft 16,
The land portions 32 and the concave grooves 34 extending in the axial direction are alternately formed along the circumferential direction. In the valve shaft 16, a communication oil hole 3 for guiding pressure oil to an inner peripheral space 38 of the valve shaft 16 is formed in a concave groove 34 facing the land portion 22 where the pressure oil hole 26 of the valve body 14 is not formed.
6 are formed through.

Further, a return oil hole 19 for guiding pressure oil to a reservoir tank (not shown) is formed through the valve shaft 16 at a portion not corresponding to the valve body 14.

The valve shaft 16 and the valve body 1
4 indicates that when the torsion bar 18 is not twisted (the steering is in a neutral state), the concave groove 24 of the valve body 14 and the land 32 of the valve shaft 16
As shown in the figure, the center parts in the circumferential direction are aligned and opposed,
A predetermined gap 39 is formed between the land 32 and the land 22 of the valve body 14 on both sides in the circumferential direction. This gap 39 becomes a throttle when the valve shaft 16 and the valve body 14 rotate relative to each other.

On the other hand, a steering reaction force control unit 40 is provided in the valve housing 12 below the valve body 14 in FIG. As shown in detail in FIG.
Has a plunger holder 42 into which the lower end of the valve shaft 16 is fitted. In the plunger holder 42,
A pair of recesses 48 are formed on the outer peripheral side.
A hydraulic chamber 50 is provided between the valve housing 8 and the valve housing 12.

The plunger holder 42 corresponding to the hydraulic chamber 50 has two pairs (four) of plungers 46A,
46B and plungers 47A and 47B are movably held, respectively. Here, a pair of plungers 46
A and 46B are valve shafts 16 in a cross-sectional view orthogonal to the axis of the valve shaft 16 (that is, FIG. 2).
Is held movably axis perpendicular to the axis with respect to (2 imaginary line L ₁₎ are inclined at a predetermined angle. Similarly, the pair of plungers 47A and 47B are viewed from a cross section orthogonal to the axis of the valve shaft 16 (ie, FIG. 2).
In FIG. 2, the valve shaft 16 is held movably at a predetermined angle with respect to an axis perpendicular to the axis of the valve shaft 16 (the imaginary line L _{2 in} FIG. ₂ ).

Further, these plungers 46A, 46
B and the plungers 47A and 47B each have one side surface facing the hydraulic chamber 50. Each plunger 46A, 46
B and the plungers 47A, 47B, on the side opposite to the hydraulic chamber 50, a projection 49 is formed.
6 are opposed to the respective side surfaces of a pair of plate-like lever portions 44 formed at the lower end portion. Thereby, the plunger 4
Reference numeral 6 denotes a configuration in which the protrusion 49 presses the lever portion 44 due to an increase in the pressure of the hydraulic chamber 50.

Next, the operation of the first embodiment will be described. In the control valve 10 (vehicle steering control device) having the above configuration, the pressure oil supplied from the hydraulic pump is diverted by the diverter valve, and then the central annular groove 20 </ b> B of the control valve 10.
It is introduced into the concave groove 34 of the valve shaft 16 through the pressure oil hole 26, and is introduced into the concave groove 24 of the valve body 14 adjacent on both sides through the gap 39 on both sides in the circumferential direction of the concave groove 34. The pressure oil introduced into the groove 24 is
4 is introduced into the groove 34 communicated with the communication oil hole 36 through the gap 39 on the opposite side to the groove 34, and is returned to the reservoir tank through the communication oil hole 36 and the inner peripheral space 38.

When the steering is in a neutral state,
Since the torsion bar 18 is not twisted, the opening areas of the gaps 39 located on both circumferential sides of the concave groove 34 facing the pressure oil hole 26 become equal as shown in FIG. At this time, no pressure difference occurs between the concave grooves 24 on both sides of the land portion 22 in which the pressure oil hole 26 is formed, and the pressure in the right oil chamber and the pressure in the left oil chamber of the power cylinder become equal, No assist force is generated in the power cylinder.

When the steering wheel is rotated and the torsion bar 18 is twisted, the valve body 14
Relative angular displacement occurs between the valve shaft 16 and the valve shaft 16, resulting in a difference in the opening area of the gap 39 on both circumferential sides of the concave groove 34. As a result, one gap 39 (a gap on the opposite side in the rotation direction) is narrowed between the concave grooves 24 on both sides of the land portion 22 in which the pressure oil hole 26 is formed, so that a pressure difference is generated, and the power connected to these is reduced. A pressure difference also occurs between the two oil chambers of the cylinder, and an assist force is generated in the steering direction. When the valve shaft 16 is displaced relative to the valve body 14, the lever portion 44 of the valve shaft 16
Is the plunger 46A, 47A or the plunger 46
B and 47B are pressed.

Further, as the vehicle speed increases, the amount of oil increases, and the reaction force applied to the steering reaction force control unit 40 (hydraulic chamber 50) increases. Thereby, the reaction force by the plungers 46A, 47A or the plungers 46B, 47B (arrow F in FIG. 2)
_R or F _L ) increases. Therefore, as the steering force, in addition to the torsion torque of the torsion bar 18, the plungers 46A and 47A or the plunger 4
Since the reaction force of 6B and 47B acts, a stable steering feeling with a sense of response can be obtained.

Here, in the control valve 10 (vehicle steering control device), the plunger 4
6A and 46B are held at a predetermined angle with respect to an axis (imaginary line L _{1 in} FIG. 2) orthogonal to the lever portion 44 of the valve shaft 16, and the plungers 47A and 47B are also orthogonal to the lever portion 44 of the valve shaft 16. axis that because they are held inclined at a predetermined angle with respect to (2 imaginary line L _2), in other words, the plunger 46A, the valve shaft 16 (the lever portion 44) during operation of the control valve 10 4
6B and the direction of input to the plungers 47A and 47B,
These plungers 46A, 46B and plunger 47
Since the actual moving directions of the A and 47B are different (inclined), the plungers 46A and 46B and the plungers 47A and 47A,
With the movement of 47B, sliding frictional resistance is generated at the outer peripheral portion of each plunger (that is, between the plunger holder 42). As a result, hysteresis is generated in the steering torque-hydraulic characteristic, the feeling of response at the start of steering operation (at the time of turning) is improved, and the steering force at the time of steering wheel steering is reduced, so that a good steering feeling is obtained. Obtainable.

Also, as just described, the plunger 46A,
Hysteresis in the steering torque-hydraulic characteristic can be obtained only by providing the moving directions of the 46B and the plungers 47A and 47B at a predetermined angle with respect to the pressing direction of the valve shaft 16 by the lever portion 44. In other words, In addition, since it is not necessary to provide an O-ring or an annular groove for accommodating the O-ring in the plunger in order to obtain the hysteresis characteristic as in the related art, the configuration is simplified and the number of parts does not increase.

Further, by changing the inclined state of the plungers 46A, 46B and the plungers 47A, 47B, the sliding friction resistance generated on the outer peripheral portions of the plungers 46A, 46B and the plungers 47A, 47B is changed, and the hysteresis characteristic is obtained. Can also be adjusted.

As described above, the control valve 10 (vehicle steering control device) can provide a large hysteresis in the steering torque-hydraulic characteristic with a simple structure without increasing the number of parts.

Next, another embodiment of the present invention will be described. Note that components that are basically the same as those in the first embodiment are given the same reference numerals as in the first embodiment, and descriptions thereof are omitted.

FIG. 4 shows a control valve 6 according to the second embodiment.
A zero steering reaction force control unit 62 is shown. In the steering reaction force control unit 62, only the pair of plungers 46A and 46B are perpendicular to the axis of the valve shaft 16 (FIG. 4), and are perpendicular to the lever 44 of the valve shaft 16 (the imaginary line in FIG. 4). L ₁ ) is held movably at a predetermined angle with respect to L ₁ ), while the pair of plungers 47A and 47B are
Is held so as to be movable along an axis orthogonal to.

In the control valve 60 (steering reaction force control section 62), when the valve shaft 16 is displaced relative to the valve body 14, the lever section 44 of the valve shaft 16
Is the plunger 46A, 47A or the plunger 46
B and 47B are pressed. Further, the amount of oil increases with an increase in vehicle speed, and the reaction force applied to the steering reaction force control unit 62 (the hydraulic chamber 50) increases. Thereby, the plunger 46
The reaction force of A, 47A or plungers 46B, 47B increases. Therefore, as the steering force, in addition to the torsional torque of the torsion bar 18, the reaction force of the plungers 46A and 47A or the plungers 46B and 47B acts, so that a stable and stable steering feeling can be obtained.

In the control valve 60, the plungers 46A and 46B are held at a predetermined angle with respect to the axis perpendicular to the lever 44 of the valve shaft 16 in the steering reaction force control unit 62. Plunger 46
A sliding frictional resistance is generated in the outer peripheral portion of each plunger (between the plunger holder 42) with the movement of A and 46B. As a result, hysteresis is generated in the steering torque-hydraulic characteristic, the feeling of response at the start of steering operation (at the time of turning) is improved, and the steering force at the time of steering wheel steering is reduced, so that a good steering feeling is obtained. Obtainable.

Also, as just described, the plunger 46A,
The moving direction of 46B is changed to the lever portion 4 of the valve shaft 16.
Hysteresis in the steering torque-hydraulic characteristic can be obtained only by providing a predetermined angle with respect to the pressing direction of 4, and thus the configuration is simplified and the number of parts does not increase.

Also in this case, the plunger 46A,
If the inclined state of 46B is changed, plungers 46A,
The sliding friction resistance generated on the outer peripheral portion of 6B is changed, and the hysteresis characteristic can be adjusted.

As described above, the control valve 60 can provide a large hysteresis in the steering torque-hydraulic characteristic with a simple structure without increasing the number of parts.

FIG. 5 shows a control valve 7 according to the third embodiment.
A zero steering reaction force control unit 72 is shown. In this steering reaction force control unit 72, only one of the plungers 46 </ b> B and 47 </ b> B is positioned at a predetermined angle with respect to an axis orthogonal to the lever 44 of the valve shaft 16 in a sectional view orthogonal to the axis of the valve shaft 16 (FIG. 5). The other plunger 46A and the other plunger 47A are held movably along an axis perpendicular to the lever portion 44 of the valve shaft 16.

Also in the control valve 70 (steering reaction force control unit 72), a stable steering feeling with a sense of response is obtained by the reaction force of the plungers 46A and 46B or the plungers 47A and 47B.

Further, in the control valve 70, since the plunger 46B and the plunger 47B are held at a predetermined angle in the steering reaction force control section 72,
With the movement of B and 46B, sliding frictional resistance is generated on the outer peripheral portion of each plunger, and hysteresis occurs in steering torque-hydraulic characteristics. Therefore, the feeling of response at the start of steering operation (at the time of turning) is improved, and the steering force at the time of steering wheel steering is reduced, so that a good steering feeling can be obtained.

Also in this case, the structure is simplified and the number of parts does not increase, and the hysteresis characteristic can be adjusted.

FIG. 6 shows a control valve 8 according to the fourth embodiment.
The zero steering reaction force control unit 82 is shown.

This steering reaction force control unit 82 is provided with the first
Although the structure is basically the same as that of the steering reaction force control unit 40 according to the embodiment, the inclination direction of the pair of plungers 46A, 46B and the plungers 47A, 47B is set to the axis orthogonal to the lever 44 of the valve shaft 16. On the other hand, it is held in the opposite direction to that described above.

Also in the control valve 80 (steering reaction force control unit 82), a stable steering feeling with a sense of response can be obtained by the reaction force of the plungers 46A, 46B or the plungers 47A, 47B.

Further, in the control valve 80, in the steering reaction force control unit 82, sliding friction resistance is generated on the outer peripheral portion of each plunger with the movement of the plungers 46A and 46B and the plungers 47A and 47B, and the steering torque-hydraulic characteristic Causes hysteresis. Therefore, the feeling of response at the start of steering operation (at the time of turning) is improved, and the steering force at the time of steering wheel steering is reduced, so that a good steering feeling can be obtained.

Also in this case, the structure is simplified and the number of parts does not increase, and the hysteresis characteristic can be adjusted.

FIG. 7 shows a control valve 9 according to the fifth embodiment.
A zero steering reaction force control unit 92 is shown. In this steering reaction force control unit 92, only one plunger 46B and one plunger 47B are held movably at a predetermined angle with respect to an axis orthogonal to the lever unit 44 of the valve shaft 16, while the other plunger 46A is held. And plunger 47A
Is held movably along an axis perpendicular to the lever portion 44 of the valve shaft 16.

Also in the control valve 90 (steering reaction force control unit 92), a stable steering feeling with a sense of response is obtained by the reaction force of the plungers 46A and 46B or the plungers 47A and 47B. Also in this case, the structure is simplified and the number of parts does not increase.
Hysteresis characteristics can also be adjusted.

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

As described above, the steering control apparatus for a vehicle according to the present invention is excellent in that a large hysteresis can be imparted in the steering torque-hydraulic characteristic without increasing the number of parts with a simple structure. Has an effect.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an overall configuration of a control valve (vehicle steering control device) according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view perpendicular to an axis of a steering reaction force control unit of the control valve according to the first embodiment of the present invention.

FIG. 3 is a schematic half sectional view taken along a direction perpendicular to the axis of the control valve according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view perpendicular to an axis of a steering reaction force control unit of a control valve according to a second embodiment of the present invention.

FIG. 5 is a sectional view perpendicular to an axis of a steering reaction force control unit of a control valve according to a third embodiment of the present invention.

FIG. 6 is a sectional view perpendicular to an axis of a steering reaction force control unit of a control valve according to a fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view perpendicular to an axis of a steering reaction force control unit of a control valve according to a fifth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 control valve (vehicle steering control device) 12 valve housing 14 valve body 15 pinion shaft 16 valve shaft 18 torsion bar 40 steering reaction force control unit 42 plunger retainer 44 lever unit 46A plunger 46B plunger 47A plunger 47B plunger 49 projection 50 hydraulic pressure Room 60 Control valve (vehicle steering control device) 62 Steering reaction force control unit 70 Control valve (vehicle steering control device) 72 Steering reaction force control unit 80 Control valve (vehicle steering control device) 82 Steering reaction force control unit 90 Control valve (vehicle steering control device) 92 Steering reaction force control unit

Claims (1)

(57) [Claims] 1. A steering mechanism for mechanically connecting a steering wheel and a steered wheel, and a hydraulic control valve comprising a valve shaft and a valve body and disposed in the middle of the steering mechanism. An assist mechanism for controlling a fluid by a relative displacement between the valve shaft and the valve body of the hydraulic control valve to obtain a steering assist force in accordance with a steering torque; a lever portion provided on the valve shaft; At least the steering mechanism is provided in association with a hydraulic control valve of the assist mechanism, and is urged by an oil liquid from a hydraulic pressure source to apply a steering reaction force to the valve shaft via the lever portion and to have reaction directions opposite to each other. A steering reaction mechanism having a pair of plungers and controlling a reaction force applied to a steering force; and Direct the plunger's movement direction to the lever
A vehicle steering control device, which is provided at a predetermined angle with respect to an intersecting axis .