JPH1029552A - Vehicular steering controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a predetermined load on steering in advance and impart a smooth, excellent feeling to steering without requiring higher positioning accuracy for the controller used therefor. SOLUTION: A control valve is formed at its V-notched ring 40 fixed to the valve body with a groove part 42 in which a ball 52 is disposed. A reaction- force plate 50 is fixed on the valve shaft so as to be displaceable in the axial direction thereof to hold the ball 52 by applying pressure thereto. The coefficients of friction are set for these members such that the static frictional forces between the ball 52 and the groove part 42 and between the ball 52 and the reaction-force plate 50 are larger than the torque that the reaction-force plate 50 applies to the ball 52. As a result of which, the reaction-force plate 50 following the rotation of the valve shaft applies torque to the ball 52 to thereby slidingly move the ball 52 within the groove part 42 with no slippage caused, which effects a preset load on steering.

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 vehicle steering control having a hydraulic control valve for controlling supply and discharge of a hydraulic pressure by a relative displacement between a valve shaft and a valve body. Related to the device.

[0002]

2. Description of the Related Art As a steering control device for a vehicle such as an automobile (for example, a hydraulic power steering device), a power steering device having a hydraulic control valve is known (for example, Japanese Patent Application Laid-Open No. 6-321124). ).

[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. In this hydraulic control valve, a plurality of guide holes penetrating in the axial direction are formed in a flange portion provided on the output shaft, and a ball is inserted into each guide hole. Furthermore, a V-shaped groove is provided on the input shaft so as to face the ball, and the ball is in contact with each V-shaped groove. Furthermore, each ball is pressed and urged by a hydraulic piston, and is held in each V-shaped groove.

When the valve shaft is rotated by the steering operation, the balls held in the respective V-shaped grooves need to move in these V-shaped grooves, so that the balls move through the V-shaped grooves. In this configuration, the moving force acts as an initial steering force (preset load) at the start of steering.

However, in the power steering apparatus using such a hydraulic control valve, as described above, the guide hole and the V-shaped groove for holding the ball for applying the initial steering force (preset load) at the start of steering are provided. Since the input shaft (valve shaft) and the output shaft (valve body) are provided at equal intervals in the circumferential direction at opposing portions, the positioning (position accuracy) of each guide hole (ball) and V-shaped groove can be accurately performed. If not performed, the force for the ball to move in the V-shaped groove changes discontinuously, causing a sense of step in the steering force. That is, the characteristic of the relative displacement angle θ-the steering torque T changes in a stepped manner from the start of the steering (T = 0) to the time when the preset load (T = T ₀ ) is reached, so that the steering feeling is reduced. There was a problem of lowering.

Further, since the ball is slidably received in the guide hole, friction occurs between the guide hole and the ball, and the size of the ball changes due to the reaction force. Also, there is a problem that the steering feeling is deteriorated.

[0007]

In view of the above facts, the present invention not only can obtain a predetermined preset load, but also can provide a good steering without stepping feeling without requiring high assembly position accuracy. It is an object of the present invention to provide a vehicle steering control device that can provide a feeling.

[0008]

According to a first aspect of the present invention, there is provided a steering control device for a vehicle, which is disposed in the middle of a steering mechanism for mechanically connecting a steering wheel and a steering wheel. In a vehicle steering control device having a hydraulic control valve that controls supply and discharge of hydraulic pressure by hydraulic fluid from a hydraulic source by the hydraulic control valve, a groove provided on an axial end surface of the valve body; A spherical body disposed in the groove portion, fixed to the valve shaft so as to be non-rotatable and axially movable in opposition to an axial end surface of the valve body, and to attach the spherical body to the groove portion by a predetermined force. An annular member that is pressed and held by force,
Comprising, and static friction force between the spherical body and the groove,
And the static friction force between the spherical body and the annular member is made larger than the rotational force acting on the spherical body based on the operating torque at the time of relative displacement between the valve shaft and the valve body. .

In the vehicle steering control device according to the first aspect, the valve shaft and the valve body of the hydraulic control valve are relatively displaced in accordance with the steering of the steering wheel, whereby the supply and discharge of the hydraulic pressure from the hydraulic source is controlled. You.

In this case, a spherical body is arranged in a groove provided on the axial end face of the valve body, and the spherical body is pressed by an annular member fixed to the valve shaft and held in the groove. .

When the valve shaft is rotated by the steering operation, the annular member fixed to the valve shaft rotates together with the valve shaft, whereby a rotational force acts on the spherical body.

Here, the static frictional force between the spherical body and the groove, and the spherical body, are less than the rotational force acting on the spherical body based on the operating torque at the time of the relative displacement between the valve shaft and the valve body. Since the static frictional force between the annular member and the annular member is increased, the spherical body located in the groove moves in the groove while rolling without sliding between the annular member and the groove. The force by which the sphere moves in the groove acts as an initial steering force (preset load) at the start of steering.

In this case, the annular member which presses the spherical body for applying the initial steering force (preset load) at the start of the steering and holds the spherical body in the groove portion applies a rotational force to the spherical body by the static friction force. Since the ball is held by a guide hole or the like as in the prior art, it is not necessary to align the neutral point of the spherical body, and the positioning of the spherical body and the groove (position accuracy) is problematic. Never be. Furthermore, since the annular member is movable along the axial direction of the valve body, there is no gap between the spherical body and the annular member.

As a result, the force for the spherical body to move in the groove changes continuously, and the steering force does not have a stepped feeling, and the steering characteristics can be stabilized regardless of the steering angle. . That is, the characteristic of the relative displacement angle θ-the steering torque T changes from the start of the steering (T = 0) to the preset load (T = T
₀ ), it changes continuously, and therefore the steering feeling does not decrease. Furthermore, even if the spherical body moves in the groove, the spherical body is uniformly pressed and urged, and the direction of the load acting on the spherical body does not change, so that the generation of abnormal noise can be reduced.

As described above, in the vehicle steering control device, not only a predetermined preset load can be obtained, but also a good steering feeling without stepping feeling without requiring high assembling position accuracy is obtained. be able to.

Further, in the vehicle steering control device, by changing the urging force (elastic force) of the annular member, the preset load can be easily changed, and the steering characteristics can be easily changed. Also, since no slippage occurs between the annular member and the spherical body, no sliding frictional force is generated between them, and therefore, no hysteresis occurs in the characteristic of the relative displacement angle θ-steering torque T.

Still further, in the vehicle steering control device, the spherical body is pressed and urged by a single annular member to obtain a preset load, so that the number of parts can be reduced.

[0018]

FIG. 1 shows the overall configuration of a vehicle steering control device according to an 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 body 14 includes a valve shaft 1.
6 are fitted 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. The torsion bar 18 has one end connected to the valve shaft 16 and the other end connected to the pinion shaft 15. That is, the valve shaft 16 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 valve body 14 and the valve connected to the pinion shaft 15 are connected. A relative angular displacement is generated between the shaft and the shaft 16.

An annular groove 2 is formed on the outer peripheral surface of the valve body 14.
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. 6, a land portion 22 and a concave groove 24 extending in the axial direction are formed on the inner peripheral surface of the valve body 14.
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 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> C is formed in the concave groove 24.

Also, 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 a portion of the valve shaft 16 that does not correspond to the valve body 14.

The valve shaft 16 and the valve body 1
4 indicates that the torsion bar 18 is not twisted (the steering is in a neutral state) and the concave groove 24 of the valve body 14 and the land portion 32 of the valve shaft 16 are arranged as shown in FIG.
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, as shown in FIG.
A V-notch ring 40 is integrally fixed to the upper end face in the axial direction of No. 4. This V notch ring 40 includes
As shown in detail in FIG. 4, three V-shaped grooves 42 are formed at equal intervals in the circumferential direction. Further, balls 52 are arranged in these grooves 42 of the V notch ring 40, respectively.

A reaction plate 50 as an annular member is arranged above the V notch ring 40 so as to face the V notch ring 40. As shown in FIGS. 1 and 2, the reaction force plate 50 is non-rotatably connected to the valve shaft 16, always rotates integrally with the valve shaft 16, and can be displaced along the axial direction of the valve shaft 16. I have. One end of a spring 68 is connected to the upper surface of the reaction force plate 50, and the other end of the spring 68 is locked by a plate 70 attached to the valve shaft 16. As a result, the reaction force plate 50 is connected to the spring 68.
The axially upper end face of the valve body 14 (the groove 4
The ball 52 is urged toward 2) to press the ball 52. The ball 52 is pressed and urged in a sandwiched state between the reaction force plate 50 and the groove 42 and held in the groove 42. When the reaction plate 50 rotates together with the valve shaft 16,
The lower surface of the reaction force plate 50 presses the ball 52 to apply a rotational force (moving force) to the ball 52.

Here, the static friction force between the ball 52 and the groove portion 42 and the static friction force between the ball 52 and the reaction plate 50 depend on the operating torque when the valve shaft 16 and the valve body 14 are displaced relative to each other. The friction coefficient of each part is set so that the reaction force plate 50 becomes larger than the rotational force applied to the ball 52 based on the above.

In this case, the set value of the friction coefficient will be described in more detail. As shown in FIG. 5, the relationship between the ball 52 located in the groove 42 and the reaction force plate 50 is as follows.
When the rotational force F ₁ to the reaction force plate 50 is applied to the ball 52 based on the operating torque at the time of relative displacement of the valve shaft 16 and the valve body 14 increases, the ball 52 rides on one of the inclined surfaces of the groove 42 , N ₂ = 0. Here, φ: the inclination angle of the groove 42 μ ₁ : the coefficient of friction between the ball 52 and the reaction force plate 50 μ ₂ : the coefficient of friction between the ball 52 and the groove 42, the balance in the vertical direction: W = N ₁ cos φ + F ₂ sin φ Balance in the left-right direction: N ₁ sin φ = F ₁ + F ₂ cos φ Balance of moment: F ₁ = F ₂ holds. By these, the relationship of N ₁ = WF ₁ = (sin φ / 1 + cos φ) · W is established. Therefore, if it is set so that (sin φ / 1 + cos φ) <μ ₁ (sin φ / 1 + cos φ) <μ ₂ , the reaction force plate 50 can apply a rotational force to the ball 52 by the static friction force, and the groove portion 42 The ball 52 located inside moves in the groove 42 while rolling between the reaction force plate 50 and the groove 42 without causing slippage.

Next, the operation of the present embodiment will be described. In the control valve 10 (vehicle steering control device) having the above-described configuration, the pressure oil supplied from the hydraulic pump is diverted by the diverter valve, and then is passed through the central annular groove 20B and the pressure oil hole 26 of the control valve 10. It is introduced into the concave groove 34 of the valve shaft 16 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 introduced into the groove 34 communicated with the communication oil hole 36 through a gap 39 on the side of the groove 24 opposite to the groove 34, and the communication oil hole 3 is formed.
6. Returned to the reservoir tank via 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 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 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.

Here, a ball 52 is disposed in a groove 42 provided on an axial end surface (V notch ring 40) of the valve body 14, and is pressed by a reaction force plate 50 and held in the groove 42. I have. When the valve shaft 16 is rotated by the steering operation, the reaction force plate 50 fixed to the valve shaft 16 is interlocked with the rotation and rotates while pressing the ball 52, and a rotational force (moving force) acts on the ball 52. I do.

Here, the rotational force acting on the ball 52 based on the operating torque when the valve shaft 16 and the valve body 14 are displaced relative to each other is smaller than the rotational force acting on the ball 52.
Since the static friction force between the ball 52 and the groove portion 42 and the static friction force between the ball 52 and the reaction force plate 50 are increased, the ball 52 located in the groove portion 42 has the reaction force plate 50 and the groove portion 42. Groove 4 while rolling without slipping between
Move in 2 The force by which the ball 52 moves in the groove 42 acts as an initial steering force (preset load) at the start of steering.

In this case, the reaction force plate 50 which presses the ball 52 for applying the initial steering force (preset load) at the time of starting the steering and holds the ball 52 in the groove portion 42 is applied to the ball 52 by the static friction force. Since the configuration is such that a rotational force is applied and the ball 52 is not held by a guide hole or the like as in the related art, the neutral position of the ball 52 is not essentially required to be positioned, and the positioning of the ball 52 and the groove 42 ( Position accuracy) does not matter. Further, since the reaction plate 50 is movable along the axial direction of the valve body 14, no gap is generated between the ball 52 and the reaction plate 50.

As a result, the force required for the ball 52 to move in the groove 42 changes continuously, so that the steering force does not have a stepped feeling and the steering characteristics can be stabilized regardless of the steering angle. it can. That is, as shown in FIG. 7, the characteristic of the relative displacement angle θ-the steering torque T continuously changes from the start of the steering (T = 0) to the time when the preset load (T = T ₀ ) is reached. Therefore, the steering feeling does not decrease. Furthermore, even if the ball 52 moves in the groove 42, the ball 52 is uniformly pressed and urged, and the direction of the load acting on the ball 52 does not change. Therefore, the steering characteristic is improved regardless of the steering angle. It is possible to stabilize and reduce the occurrence of abnormal noise.

As described above, the control valve 10 (vehicle steering control device) can not only obtain a predetermined preset load, but also can provide a good and smooth feeling without stepping without requiring high assembly position accuracy. A steering feeling can be obtained.

Control valve 10 (vehicle steering control device)
In this case, the preset load can be easily changed by adjusting the biasing force (elastic force) of the spring 68 (the reaction plate 50) by screwing the plate 70 to the valve shaft 16 so as to be adjustable in the axial direction. In addition, the steering characteristics can be easily changed. Also, the reaction force plate 50 and the ball 5
Since no slip occurs between the two, no slip friction force is generated between the two, and therefore, no hysteresis occurs in the characteristic of the relative displacement angle θ-steering torque T.

Further, in the control valve 10 (vehicle steering control device), the ball 52 is pressed and urged by a single reaction force plate 50 to obtain a preset load, so that the number of parts can be reduced. it can.

[0041]

As described above, the vehicle steering control device according to the present invention not only can obtain a predetermined preset load, but also does not require a high assembling position accuracy and does not have a stepped feeling. It has an excellent effect that a good steering feeling can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an entire configuration of a control valve according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a correspondence relationship between a V notch ring, a ball, a reaction plate and the like of the control valve according to the embodiment of the present invention.

FIG. 3 is a plan sectional view showing a correspondence relationship among a valve shaft, a reaction plate, a ball, and the like of the control valve according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a correspondence relationship between a reaction force plate, a ball, a groove, and the like of the control valve according to the embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a correspondence relationship between forces acting on a reaction plate, a ball, a groove, and the like of the control valve according to the embodiment of the present invention.

FIG. 6 is a schematic half-sectional view taken along a direction perpendicular to the axis of the control valve according to the embodiment of the present invention.

FIG. 7 is a graph showing characteristics of relative displacement angle θ-steering torque T by the control valve according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Control valve (vehicle steering control device) 12 Valve housing 14 Valve body 16 Valve shaft 18 Torsion bar 40 V notch ring 42 Groove 50 Reaction plate (annular member) 52 Ball (spherical body) 68 Spring

Continued on the front page (72) Inventor Miyuki Ouchi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Shoji Yamashita 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Moriki Tashiro 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Masaaki Chiga 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (1)

[Claims] A hydraulic control valve disposed in a steering mechanism for mechanically connecting a steering wheel and a steered wheel to supply and discharge hydraulic pressure by a relative displacement between a valve shaft and a valve body; In the vehicle steering control device for controlling the oil liquid by the hydraulic control valve, a groove provided on an axial end face of the valve body, a spherical body disposed on the groove, and an axial end face of the valve body An annular member which is fixed to the valve shaft so as to be non-rotatable and movable in the axial direction, and presses and holds the spherical body toward the groove with a predetermined urging force; and The static friction force between the body and the groove and the static friction force between the spherical body and the annular member are determined based on the operating torque at the time of relative displacement between the valve shaft and the valve body. Was greater than the rotational force acting on the spherical body, a vehicle steering control apparatus characterized by.