JP3147768B2 - 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 a steering control device for performing manual steering and an automatic steering mode for automatically performing steering. The present invention relates to a vehicle steering control device.

[0002]

2. Description of the Related Art In a steering control device (for example, a hydraulic power steering device) for a vehicle such as an automobile, a steering operation is performed by detecting a traveling state of a vehicle and a manual steering mode in which a driver operates a steering wheel. There is a power steering device that can selectively switch between an automatic steering mode and an automatic steering mode (for example, see Japanese Patent Application Laid-Open No. Sho 62-43).
361).

The power steering apparatus disclosed in this publication includes a hydraulic actuator for steering a steered wheel, and a hydraulic steering system for distributing and controlling the hydraulic pressure from a hydraulic pump by operating a steering wheel to perform steering. In the mode, the steering wheel is steered by supplying hydraulic pressure from the automatic steering hydraulic system.

However, this power steering apparatus is provided with an automatic steering hydraulic system used in an automatic steering mode, in addition to a hydraulic steering system used in a normal operation (manual steering mode in which steering is performed by steering). Therefore, the configuration of the hydraulic circuit and the like is complicated as a whole, and there is a problem in terms of arrangement space and cost.

[0005]

In view of the above facts, the present invention not only can selectively switch between a manual steering mode and an automatic steering mode, but also has a simple structure and can be provided at low cost. The purpose is to get the device.

[0006]

According to a first aspect of the present invention, there is provided a steering control apparatus for a vehicle, which detects a traveling state of a vehicle and a manual steering mode in which a driver operates a steering wheel to automatically perform steering. A steering control device for a vehicle capable of selectively switching an automatic steering mode to be performed, comprising: a steering mechanism that mechanically connects a steering wheel and a steered wheel; and a hydraulic control valve disposed in the middle of the steering mechanism. An assist mechanism for controlling an oil liquid from a hydraulic source by the hydraulic control valve to obtain a steering assist force according to a steering torque;
The steering mechanism is provided in connection with a hydraulic control valve of the assist mechanism in the middle of the steering mechanism, and is urged by an oil liquid from a hydraulic source to apply a steering reaction force to the steering mechanism. Has a pair of plungers opposed to each other, and controls a reaction force applied to the steering force, and evenly supplies hydraulic pressure to the pair of plungers of the steering reaction force mechanism based on the selected steering mode. And a hydraulic pressure switching means for controlling the supply of the hydraulic pressure in a state in which the hydraulic pressure is supplied to one of the plungers based on the steering direction.

In the vehicle steering control device according to the first aspect, in a manual steering mode in which the driver operates the steering wheel by operating the steering wheel, when the steering wheel is operated, the steered wheels are steered by the steering mechanism. A steering assist force according to the steering torque is applied by the assist mechanism. Further, in this manual steering mode, the hydraulic pressure is uniformly supplied to the pair of plungers of the steering reaction force mechanism by the operation of the hydraulic pressure switching means, whereby a predetermined reaction force is applied to the steering force of the steering mechanism, and the steering force is stabilized. Steering feeling is obtained.

On the other hand, in the automatic steering mode in which the steering state is detected and the steering is automatically performed, the hydraulic pressure is supplied to one of the corresponding plungers based on the left and right steering directions by operating the hydraulic switching means. Supplied. For this reason,
The hydraulic control valve of the assist mechanism is operated in conjunction with the urging force of one of the selected (to which the hydraulic pressure is supplied) plunger, and a steering force is applied to the steering mechanism to steer the steered wheels.

As described above, the supply of the hydraulic pressure to the pair of plungers of the steering reaction force mechanism can be selectively switched between the manual steering mode and the automatic steering mode only by controlling the switching by the hydraulic pressure switching means. Is simple and cheap.

[0010]

FIG. 1 shows the overall configuration of a vehicle steering control device 70 according to an embodiment of the present invention.

The vehicle steering control device 70 includes a control valve 10 that constitutes an assist mechanism and a steering reaction force mechanism. As shown in detail in FIG. 2, the control valve 10 has a cylindrical valve housing 12, and a valve sleeve 14 is disposed in the valve housing 12 so as to be relatively rotatable. The valve sleeve 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.

A valve shaft 16 is fitted to the valve sleeve 14 so as to be relatively rotatable. The valve shaft 16 is connected to an input shaft (not shown).

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 input shaft, and the other end is connected to the pinion shaft 15. That is, the input shaft is connected to the pinion shaft 15 via the torsion bar 18, and when the torsion bar 18 is twisted by the turning operation of the steering, the input shaft is connected to the valve sleeve 14 connected to the pinion shaft 15. A relative angular displacement is generated between the shaft and the valve shaft 16 connected to the shaft.

On the outer peripheral surface of the valve sleeve 14, annular grooves 20A, 20B and 20C are formed at predetermined intervals in the axial direction, and the central annular groove 20B is connected to a hydraulic pump 52 via a hydraulic circuit described later in detail. The upper annular groove 20A in the axial direction is connected to an oil chamber on the right side of a power cylinder (not shown), and the lower annular groove 20C in the axial direction is connected to an oil chamber on the left side of the power cylinder. .

As shown in FIG. 5, on the inner peripheral surface of the valve sleeve 14, land portions 22 and concave grooves 24 extending in the axial direction are formed alternately along the circumferential direction. A pressure oil hole 26 for introducing hydraulic pressure from a hydraulic pump 52 into the control valve 10 through a central annular groove 20 </ b> B is formed through the valve sleeve 14 in the radial direction of the land portion 22. Further, a suction / discharge oil hole 28 communicating with one annular groove 20C 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 is discharged to, for example, a left oil chamber of the power cylinder. An oil suction / discharge hole 30 communicating with the annular groove 20 </ b> B is formed in the concave groove 24.

On the other hand, 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 36 for guiding pressure oil to the inner peripheral space 38 of the valve shaft 16 penetrates through a concave groove 34 facing the land portion 22 where the pressure oil hole 26 of the valve sleeve 14 is not formed. Is formed.

As shown in FIG. 2, the valve shaft 16 has a return oil hole 1 for guiding pressure oil to a reservoir tank 21 (see FIG. 1) at a portion not corresponding to the valve sleeve 14.
9 are formed through.

In the state where the torsion bar 18 is not twisted (neutral state of steering), the groove 24 of the valve sleeve 14 and the land 32 of the valve shaft 16 are connected to the valve shaft 16 and the valve sleeve 14 in FIG. As shown in the figure, the valve sleeves 1 are opposed to each other in the circumferential direction so that the center portions in the circumferential direction are aligned.
A predetermined gap 39 is formed between the second land portion 22 and the fourth land portion 22. This gap 39 is provided in the valve shaft 1
When the valve sleeve 6 and the valve sleeve 14 rotate relative to each other, it becomes a throttle portion.

Further, as shown in FIG. 2, a steering reaction force control section 40 as a steering reaction force mechanism is provided in the valve housing 12 below the valve sleeve 14 in the figure. The steering reaction force control unit 40 includes a plunger holder 42 into which the lower end of the valve shaft 16 is fitted.

As shown in FIGS. 3 and 4, the plunger holder 42 is formed with a pair of recesses 48 and a pair of recesses 49 on the outer peripheral side, and the gap between the recess 48 and the valve housing 12 is provided. In addition to the hydraulic chamber 50, the recess 49
A hydraulic chamber 51 is provided between the valve housing 12 and the valve housing 12. That is, the hydraulic chamber 50 and the hydraulic chamber 51 which are separated and independent from each other in the axial direction by the plunger holder 42.
Are formed.

Two plungers 46 are slidably held in the plunger holder 42 corresponding to one hydraulic chamber 50. These plungers 46 are located diagonally to each other in a cross section orthogonal to the device axis, and each side faces the hydraulic chamber 50. A projection 46A is provided on the opposite side of each plunger 46 from the hydraulic chamber 50.
Are formed, and face the respective side surfaces of a pair of flat wings 44 formed at the lower end of the valve shaft 16. For this reason, the protrusion 46 </ b> A of the plunger 46 presses the wing 44 by the pressure increase of the hydraulic chamber 50. In this case, since the two plungers 46 are located diagonally to each other in a cross section orthogonal to the apparatus axis, the direction in which the wings 44 are pressed is the same (the CW direction in FIG. 3).

Further, two plungers 47 are slidably held in the plunger holder 42 corresponding to the other hydraulic chamber 51. These plungers 47
In a cross section orthogonal to the device axis, they are located diagonally to each other and obliquely to the plunger 46 described above. On the opposite side of each plunger 47 from the hydraulic chamber 51, a projection 47A is provided.
Are formed, and face the respective side surfaces of the pair of wing portions 44 formed at the lower end portion of the valve shaft 16. For this reason, the protrusion 47A of the plunger 47 presses the wing portion 44 due to an increase in the pressure of the hydraulic chamber 51. Also in this case, since the two plungers 47 are located diagonally to each other in a cross section orthogonal to the apparatus axis, the direction in which the wings 44 are pressed is the same. Further, since these plungers 47 are positioned obliquely with respect to the plunger 46, the plunger 46 is
The wing portion 44 is pressed in a direction opposite to the direction in which the wing portion 4 is pressed (in the CCW direction in FIG. 4).

The control valve 10 having the above configuration is connected to a hydraulic circuit as shown in FIG. In this hydraulic circuit, the annular groove 20B of the control valve 10 (the pressure oil hole 26 of the valve sleeve 14) is connected to the hydraulic pump 52 via the flow dividing valve 54, and the return oil hole 19 of the control valve 10 is It is connected to a reservoir tank 21. Therefore, the oil liquid discharged from the hydraulic pump 52 is diverted by the diverting valve 54, a part is supplied to the control valve 10 (the valve sleeve 14 and the valve shaft 16), and is returned to the reservoir tank 21. .

A directional switching valve 56 as hydraulic switching means is connected to the flow dividing valve 54, and the directional switching valve 56 is connected to a hydraulic pressure control unit 40 provided in the steering reaction force control unit 40 of the control valve 10. The chamber 50 and the hydraulic chamber 51 are connected independently. Therefore, the oil liquid discharged from the hydraulic pump 52 is divided by the flow dividing valve 54 and supplied to the direction switching valve 56. Direction switching valve 56
6A shows a state in which the oil liquid supplied from the flow dividing valve 54 is equally supplied to both the hydraulic chamber 50 and the hydraulic chamber 51 as shown in FIG. 6A, and FIG. 6B or FIG. 6C. The switching operation can be performed in such a state that the supplied oil liquid is supplied to one of the hydraulic chambers.

Further, a solenoid valve 58 is connected to the flow dividing valve 54. This solenoid valve 58
By operating and changing the flow path restriction area, the flow dividing valve 5
4 (in other words, the amount of oil liquid to be diverted by the flow dividing valve 54 and supplied to the direction switching valve 56), whereby the reaction force pressure of the steering reaction force control unit 40 can be controlled. can do.

The flow dividing valve 54 has a fixed orifice 6.
0 is connected in parallel in a hydraulic circuit. When the pressure on the annular groove 20B of the control valve 10 (the pressure oil hole 26 of the valve sleeve 14) increases, the fixed orifice 60 transfers the oil liquid to the direction switching valve 56 (that is, the steering reaction force control unit 4).
0 side).

The controller 62 constituting the hydraulic pressure switching means is connected to the solenoid valve 58 and the direction switching valve 56 of the hydraulic circuit having the above-described configuration. The controller 62 receives a vehicle speed signal from a vehicle speed sensor (not shown) and a mode signal of a selected steering mode (manual steering mode or automatic steering mode).
As a result, the controller 62 controls the drive of the solenoid valve 58 in accordance with the vehicle speed, and further controls the switching of the direction switching valve 56 based on the selected steering mode (manual steering mode or automatic steering mode), as well as automatic steering. Direction switching valve 56 according to the steering direction in the mode
Is controllable.

Next, the operation of the present embodiment will be described. First, a description will be given of a case where the vehicle steering control device 70 is operated in a manual steering mode in which steering is performed by a driver operating a steering wheel.

In the manual steering mode, the controller 6
The direction switching valve 56 is switched by the switching control according to 2, and the oil liquid supplied from the flow dividing valve 54 is uniformly supplied to the hydraulic chamber 50 and the hydraulic chamber 51 as shown in FIG.

Here, the pressure oil supplied from the hydraulic pump 52 is diverted by the diverting valve 54 and then diverted by the control valve 1.
0 is introduced into the concave groove 34 of the valve shaft 16 through the central annular groove 20B and the pressure oil hole 26, and the concave groove of the valve sleeve 14 adjacent on both sides through the gap 39 on both sides in the circumferential direction of the concave groove 34. 24. The pressure oil introduced into the groove 24 is introduced into the groove 34 communicated with the communication oil hole 36 via a gap 39 on the opposite side of the groove 34 in the groove 24, and the communication oil hole 36, It is returned to the reservoir tank 21 via the inner 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 are 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 sleeve 1
A relative angular displacement occurs between the valve groove 4 and the valve shaft 16, and a difference occurs in the opening area of the gap 39 on both sides in the circumferential direction 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.

Further, as the vehicle speed increases, the driving of the solenoid valve 58 is controlled, so that the amount of oil supplied from the flow dividing valve 54 to the direction switching valve 56 increases, and the steering reaction force control unit 40
The reaction pressure applied to (the hydraulic chamber 50 and the hydraulic chamber 51) is increased. Thereby, the plunger 46 and the plunger 47
The reaction force due to is increased. Therefore, as the steering force, the reaction force of the plunger 46 or the plunger 47 acts in addition to the torsional torque of the torsion bar 18, and a stable steering feeling with a sense of response is obtained.

On the other hand, in the automatic steering mode in which steering is automatically performed by detecting the running state of the vehicle, the direction switching valve 56 is switched by switching control by the controller 62 based on the automatic steering signal, and FIG. Alternatively, as shown in FIG. 6C, the hydraulic fluid supplied from the flow dividing valve 54 supplies the hydraulic pressure to one of the hydraulic chambers 50 and 51 corresponding to the left and right steering directions.

For this reason, the plunger (plunger 46 or plunger 47) of one of the hydraulic chambers selected (to which hydraulic pressure is supplied) from the hydraulic chamber 50 and the hydraulic chamber 51 is selected.
, The torsion bar 18 is twisted.
When the torsion bar 18 is twisted, a relative angular displacement occurs between the valve sleeve 14 and the valve shaft 16 as described above, and a pressure difference also occurs between the two oil chambers of the power cylinder, so that steering is performed in the steering direction. A force is generated and the steered wheels are steered.

As described above, the supply of the hydraulic pressure to the plunger 46 or the plunger 47 of the steering reaction force control unit 40 (the hydraulic chamber 50 and the hydraulic chamber 51) constituting the steering reaction mechanism is switched by the direction switching valve 56. The automatic steering mode can be selectively switched between the manual steering mode and the automatic steering mode. Further, in the automatic steering mode, the automatic steering according to the traveling state of the vehicle can be realized by controlling the switching of the direction switching valve 56. Therefore, there is no need to provide an automatic steering hydraulic system used in the automatic steering mode, and the structure is simple and inexpensive.

[0037]

As described above, the vehicle steering control device according to the present invention not only can selectively switch between the manual steering mode and the automatic steering mode, but also has a simple structure and greatly reduces the cost. It has an excellent effect that it can be achieved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a vehicle steering control device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along an axis of a control valve applied to the vehicle steering control device according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view (a cross-sectional view taken along line 3-3 in FIG. 2) perpendicular to an axis of a steering reaction force control unit of a control valve applied to the vehicle steering control device according to the embodiment of the present invention;

FIG. 4 is a cross-sectional view (a cross-sectional view taken along line 4-4 in FIG. 2) perpendicular to an axis of a steering reaction force control unit of a control valve applied to the vehicle steering control device according to the embodiment of the present invention;

FIG. 5 is a schematic half sectional view (a sectional view taken along line 5-5 in FIG. 2) perpendicular to an axis of a control valve applied to the vehicle steering control device according to the embodiment of the present invention;

FIG. 6 is a schematic configuration diagram showing an operation state of a direction switching valve applied to the vehicle steering control device according to the embodiment of the present invention.

[Description of Signs] 10 Control valve 12 Valve housing 14 Valve sleeve 16 Valve shaft 18 Torsion bar 40 Steering reaction force control unit 44 Wing unit 46 Plunger 47 Plunger 50 Hydraulic chamber 51 Hydraulic chamber 52 Hydraulic pump (hydraulic source) 54 Dividing valve 56 Direction switching valve (hydraulic switching means) 58 Solenoid valve 62 Controller (hydraulic switching means) 70 Steering control device for vehicle

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B62D 5/08-5/087 B62D 6/00-6/02

Claims (1)

(57) [Claims] 1. A vehicle steering control device capable of selectively switching between a manual steering mode in which steering is performed by a driver's steering wheel operation and an automatic steering mode in which a driving state of a vehicle is detected and steering is automatically performed. A steering mechanism for mechanically connecting a steering wheel and a steered wheel; and a hydraulic control valve disposed in the middle of the steering mechanism, wherein a hydraulic fluid from a hydraulic source is controlled by the hydraulic control valve, and a steering torque is controlled. An assist mechanism that obtains a steering assist force in accordance with a steering control force provided in the middle of the steering mechanism in association with a hydraulic control valve of the assist mechanism, and urged by an oil liquid from a hydraulic source to exert a steering reaction force on the steering mechanism. A pair of plungers which are independent of each other and have opposite reaction directions to each other, and control a reaction force applied to the steering force. A hydraulic pressure that controls switching of hydraulic pressure supply between a state in which hydraulic pressure is uniformly supplied to a pair of plungers of the steering reaction force mechanism based on a mode, and a state in which hydraulic pressure is supplied to one of the plungers based on a steering direction. A vehicle steering control device, comprising: switching means.