JP2000313348A - Hydraulic power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light feeling in steeling with a simple structure by providing a control valve for regulating the passing oil quantity by decreasing the valve opening when the steering angle of a steering wheel is minute, and increasing the valve opening at a prescribed steering angle or more. SOLUTION: The pressure oil generated by a hydraulic pump 3 is supplied to a control valve mechanism 2 through a first oil passage 15. A second oil passage 16 branched from the first oil passage 15 is connected to the oil port of a rack housing to supply the pressure oil also to a hydraulic chamber. A control valve 7 is provided between the branch point 17 of the first oil passage 15 to the second oil passage 16 and the recessed part of a valve shaft within the control valve mechanism, and the hydraulic pressure according to the opening of the control valve 7 is generated in the first and second oil passages 15, 16. The valve opening of the control valve 7 is mechanically controlled in interlocking with the steering operation by a driver, and it is set so as to be decreased when the steering angle of the steering wheel is minute and increased at a prescribed steering angle or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic power steering apparatus for a vehicle that assists a steering torque applied to a steering wheel with hydraulic pressure.

[0002]

2. Description of the Related Art In a hydraulic power steering system that assists a steering torque applied to a steering wheel with hydraulic pressure, light steering can be performed at low speed and stationary, and steering stability at high speed traveling is high. In addition, there is a demand for characteristics of high steering rigidity when the steering is neutral.

Therefore, as a means for increasing the steering stiffness, it is conceivable to increase the pressing force of a rack guide for pressing the rack gear against the pinion gear.

[0004]

However, when a means for increasing the steering rigidity by adopting a high pressing force of the rack guide is adopted, the friction of the rack gear becomes high and the light feeling at the time of steering is impaired.

On the other hand, in order to obtain a light steering feeling,
It is conceivable that the pressing force of the rack guide is set to a low value, but in this case, stability at the time of neutrality is impaired, steering rotational vibration caused by tire rotational imbalance, input of rack gear and pinion gear due to road surface input. There is a problem that a tapping sound is easily generated.

In order to solve the above problem, Japanese Patent Application Laid-Open No. Sho 54-110527 discloses a method in which a hydraulic pressure is generated so as to resist a spring force constantly pressing a rack guide, and the rack guide is pressed during steering. Power is decreasing.

For this reason, a light feeling can be obtained at the time of turning, but the pushing force of the rack guide remains low even in the holding state at the time of high-speed turning. There is a problem that the rack gear and the pinion gear are likely to be hit by rotation vibration and input from the road surface.

Further, in Japanese Patent Application Laid-Open No. 60-174364, hydraulic pressure is introduced so as to increase the pressing force of the rack guide only near the neutral position of the steering wheel. There is a problem that the rattling noise of the rack gear and the pinion gear due to the steering rotational vibration and the input from the road surface is likely to occur.

Further, in JP-A-8-188167, a vibration detecting sensor is provided in a rack housing, and the pressing force of a rack guide is increased by a hydraulic action only when vibration exceeding a predetermined value is detected. However, since the pressing force of the rack guide is increased after the occurrence of the vibration, it is difficult to suppress the vibration at the initial stage of the generation.

The present invention has been made in view of the above-mentioned problems, and has a simple structure in which the distribution hydraulic pressure of the hydraulic pressure input to the control valve mechanism is adjusted by the valve opening degree, while providing a light steering operation. It is an object of the present invention to provide a hydraulic power steering device that achieves a balance between steering feeling, stability due to high steering rigidity when steering is neutral, and good sound vibration performance.

[0011]

According to the first aspect of the present invention,
A control valve mechanism that is provided between the hydraulic pump and the reservoir tank and controls intake and exhaust of hydraulic oil to and from the power cylinder,
A valve housing of the control valve mechanism and a valve body connected to the pinion gear to be integrally rotatable are disposed so as to be relatively rotatable, and a valve shaft connected to an input shaft is fitted to the valve body so as to be relatively rotatable. The input shaft is connected to the pinion gear via a torsion bar, the input shaft and the torsion bar are relatively rotatable, and a hydraulic power steering presses the rack gear against the pinion gear at a fitting portion between the pinion gear and the rack gear. In the apparatus, a rack guide that presses the rack toward the pinion gear, a spring element that constantly applies a constant pressing force to the rack guide, and a preload device that increases the pressing force of the rack guide according to an increase in hydraulic pressure. A first oil passage connecting the hydraulic pump and the control valve mechanism,
A second oil passage branched from the first oil passage and connected to the preload device, and a branch point between the first oil passage and the second oil passage and the control valve mechanism are provided, and a steering angle of the steering is very small. In the case of (1), a control valve is provided which adjusts the amount of oil passing through by reducing the valve opening and increasing the valve opening when the steering angle is equal to or larger than a predetermined value.

According to a second aspect of the present invention, in the hydraulic power steering apparatus according to the first aspect, a projection is formed on the valve shaft in a recess opposite to a projection formed with a pressure oil hole of the valve body. The control valve mechanism is characterized in that, when the valve shaft and the valve body are not rotating relative to each other, the protrusion restricts the opening area of the pressure oil hole to be small.

According to a third aspect of the present invention, in the hydraulic power steering apparatus according to the first or second aspect, a steering angle sensor for detecting a steering angle and an opening degree of the control valve driven by a solenoid are used as the steering angle sensor. A valve control means for controlling based on the signal of the above, wherein the valve control means, if the steering angle is small, the valve opening is small, and if the steering angle is a certain value or more, means for adjusting the valve opening large. It is characterized by having done.

According to a fourth aspect of the present invention, in the hydraulic power steering apparatus according to the first or second aspect, a steering force sensor for detecting a tie rod axial force of a tie rod shaft connected to the rack, and the solenoid driven by a solenoid. Valve control means for controlling the opening of the control valve based on the signal of the steering force sensor is provided, and the valve control means is a means for adjusting the valve opening larger as the steering force is larger.

According to a fifth aspect of the present invention, in the hydraulic power steering apparatus according to the third or fourth aspect,
A vehicle speed sensor for detecting a vehicle speed is added, and the valve control means is a means for adjusting the valve opening smaller as the vehicle speed is higher when the vehicle is traveling straight.

[0016]

According to the first aspect of the present invention, in the control valve provided between the control valve mechanism and the branch point between the first oil passage and the second oil passage, the steering angle is small. The valve opening is decreased, and when the steering angle is equal to or larger than a predetermined value, the valve opening is increased. As a result, when the valve opening of the control valve is small, the amount of oil supplied to the control valve mechanism via the control valve is suppressed, and a large amount of oil is supplied to the preload device side, and the control rack guide The pressing force is kept high. Also, when the valve opening of the control valve is large, the amount of oil supplied to the control valve mechanism via the control valve is large, the amount of oil to the preload device is suppressed, and the control rack guide pressing force is kept low. Dripping.

Therefore, light steering can be performed at the time of steering operation such as stationary steering. When the steering is neutral,
High characteristics are obtained as steering rigidity, and steering stability and good sound vibration performance are obtained. In other words, it is possible to prevent the rotational vibration of the steering wheel due to the rotational imbalance of the tire and the hitting noise of the rack gear and the pinion gear due to the input from the road surface.

According to the second aspect of the present invention, the valve shaft is provided with a projection in a concave portion facing the convex portion in which the pressure oil hole is formed in the valve body. When the shaft and the valve body are not rotating relative to each other, the opening area of the pressure oil hole is limited to a small amount by the projection, and the opening area of the pressure oil hole is secured large during steering.

Accordingly, since the control valve is formed between the projection provided on the valve shaft and the pressure oil hole,
With a simple configuration, it is possible to generate a pressing force of the rack guide according to the steering state.

According to the third aspect of the present invention, in the valve control means, when the steering angle detected by the steering angle sensor for detecting the steering angle is small, the opening of the control valve by solenoid driving is performed so as to reduce the valve opening. The degree is adjusted,
When the steering angle detected by the steering angle sensor is equal to or larger than a predetermined value, the opening of the control valve driven by the solenoid is adjusted so as to increase the valve opening.

Therefore, since the control valve is constituted by a solenoid valve, the pressure of the preloading device can be adjusted immediately when steering information is detected by the steering angle sensor, so that a light steering feeling can be obtained immediately after the start of steering. Obtainable.

According to the fourth aspect of the present invention, in the valve control means, the valve opening is adjusted to be larger as the steering force detected by the steering force sensor for detecting the tie rod axial force of the tie rod shaft connected to the rack is larger. .

Accordingly, by using the tie rod axial force as the steering information for controlling the opening and closing of the control valve, the steering intention of the driver is reflected most directly, and the sensing parameter is controlled when controlling the steering force which is hardly affected by disturbance. -It can be evening.

According to the fifth aspect of the present invention, in the valve control means, the straight running is judged by the detected steering angle being in the minute area or the detected tie rod axial force is in the minute area. The higher the vehicle speed, the smaller the valve opening is adjusted.

Therefore, the sense of stability of steering during high-speed running can be further enhanced.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) The configuration of Embodiment 1 corresponding to the invention described in claim 1 will be described with reference to FIGS.

FIG. 1 is a schematic view of a hydraulic power steering device according to the first embodiment, and FIG. 2 is a sectional view showing a control valve mechanism of the hydraulic power steering device according to the first embodiment.

As shown in FIG. 1, the hydraulic power steering apparatus according to the first embodiment includes a control valve mechanism 2 for controlling the supply and discharge of hydraulic oil to and from the power cylinder 1. It is provided between the pump 3 and the reservoir tank 4.

5 is a rack gear, 6 is a retainer, 1
5 is a first oil passage, 16 is a second oil passage, and 17 is a branch point.

As shown in FIG. 2, the control valve mechanism 2 includes a cylindrical valve housing 11, and a valve body 12 is disposed in the valve housing 11 so as to be relatively rotatable. The valve body 12 has a cylindrical shape, and is connected to the pinion gear 10 so as to be integrally rotatable.

A valve shaft 13 is fitted to the valve body 12 so as to be relatively rotatable. The steering shaft 8 (input shaft) is connected to the valve shaft 13.

The steering shaft 8 is connected to a pinion gear 10 via a torsion bar 14. The steering shaft 8 and the torsion bar 14 are relatively rotatable, and when the rotation of the steering causes the torsion bar 14 to be twisted, the valve body 1 is rotated.
A relative angular displacement is generated between the valve shaft 2 and the valve shaft 13. Annular grooves 20A, 20BB, and 20C are formed at predetermined intervals in the axial direction on the outer peripheral surface of the valve body 12, the central annular groove 20A is connected to the hydraulic pump 3, and the axially upper annular groove 20B is used for power. The annular groove 20 </ b> C on the lower side in the axial direction is connected to an oil chamber on the right side of the cylinder 1, for example, and the oil chamber on the left side of the power cylinder 1 is connected.

FIG. 3 is a sectional view taken along line AA of FIG. 2. As shown in FIG. 3, convex portions 22 and concave portions 24 extending in the axial direction are alternately formed on the inner peripheral surface of the valve body 12. I have. In the valve body 12, a hydraulic pressure from the hydraulic pump 3 is applied to a portion corresponding to the convex portion 22 of the central annular groove 20 </ b> A.
A pressure oil hole 26 to be introduced into the inside is formed through. In addition, a portion of the annular groove 20B corresponding to the concave portion 24 is provided with one oil suction / discharge oil hole 28 for sucking and discharging the hydraulic pressure in, for example, a right oil chamber of the power cylinder 1, and a portion corresponding to the concave portion 24 of the annular groove 20C. In the power cylinder 1, for example, one oil suction / discharge oil hole 30 for sucking / discharging oil pressure is formed through an oil chamber on the left side of the power cylinder 1. On the other hand, convex portions 32 and concave portions 34 extending in the axial direction are alternately formed on the outer peripheral surface of the valve shaft 13 along the circumferential direction. In the valve shaft 13, a communication oil hole 36 for guiding pressure oil to an inner peripheral space 38 of the valve shaft 13 is formed through a concave portion 34 facing the convex portion 22 where the pressure oil hole 26 of the valve body 12 is not formed. .

As shown in FIG. 2, a communication oil hole 19 for guiding the pressure oil to the reservoir tank 4 is formed through a portion of the valve shaft 13 that does not correspond to the valve body 12.

The valve shaft 13 and the valve body 1
2, the concave portion 24 of the valve body 12 and the convex portion 32 of the valve shaft oppose each other in a state where the torsion bar 14 is not twisted (steering neutral state), with the central portion in the circumferential direction coinciding. Predetermined gaps 39 and 40 are formed between the projection 22 and the valve body 12 on both sides in the direction. The gaps 39 and 40 serve as throttles when the valve shaft 13 and the valve body 12 rotate relative to each other.

The pressure oil supplied from the hydraulic pump 3 is introduced into the concave portion 34 of the valve shaft 13 through the central annular groove 20A and the pressure oil hole 26,
Are introduced into the concave portions 24 of the valve body 12 adjacent on both sides through the gaps 39 on both sides in the circumferential direction. The pressure oil introduced into the concave portion 24 is introduced into the concave portion 34 connected to the communication oil hole 86 via the gap 40 on the opposite side of the concave portion 34 in the concave portion 24, and the communication oil hole 36 and the inner peripheral space portion 38
Is returned to the reservoir tank 4 via the.

When the steering is in a neutral state,
Since the torsion bar 14 is not twisted, as shown in FIG. 3, the opening areas of the gaps 39A and 39B located on both circumferential sides of the concave portion 34 facing the pressure oil hole 26 become equal. At this time, there is no pressure difference between the concave portions 24 on both sides of the convex portion 22 in which the pressure oil hole 26 is formed,
No assist force is generated in the power cylinder 1.

On the other hand, when the steering wheel is rotated, the torsion bar 14 is twisted, causing a relative angular displacement between the valve body 12 and the valve shaft 13, and the opening area of the gap 39 on both sides in the circumferential direction of the recess 34. There is a left-right difference As a result, one gap 39 (a gap on the opposite side in the rotation direction) is narrowed between the concave portions 24 on both sides of the convex portion 22 in which the pressure oil hole 26 is formed, so that a pressure difference is generated, and the pressure difference is connected. A pressure difference also occurs between the two oil chambers of the power cylinder 1, and an assist force is generated in the steering direction. Also,
As shown in FIG. 2, a rack gear 5 orthogonal to the pinion gear 10 is supported on the valve housing 11.
The teeth of the pinion gear 10 always mesh with the teeth of the rack gear 5. Therefore, when the pinion gear 10 rotates, the rack gear 5 slides along its axis, and this sliding operation is transmitted to the steered wheels (not shown) of the vehicle.

In the valve housing 11, a hydraulic chamber 42 having a cylindrical inner peripheral surface is formed on the rear side of the rack gear 5, that is, on the opposite side of the pinion gear 10.
A rack guide 44 is inserted into the hydraulic chamber 42 so as to be slidable in the vertical direction in FIG.

The rack guide 44 has a guide surface for supporting the rear surface of the rack gear 5, and guides the sliding operation of the rack gear 5.

A plug 46 is screwed into the hydraulic chamber 42 from outside the valve housing 11.

Outer peripheral surface of rack guide 44 and plug 46
Oil seals 48 and 50 are attached to the outer peripheral surface of the hydraulic chamber 42, respectively, to maintain a liquid-tight state between the outer peripheral surface and the inner peripheral surface of the hydraulic chamber 42.

Between the rack guide 44 and the plug 46,
A hydraulic chamber 42 is formed, and an oil hole 70 for introducing pressure oil from the hydraulic pump 3 into the hydraulic chamber 42 is formed in the valve housing.
Is provided. A rack guide 44 is provided in the hydraulic chamber 42.
Compression coil spring 58 between the end of the
Is incorporated. The compression coil spring 58 is for positioning the rack guide 44 in a state where the rack guide 44 is pressed against the rack gear 5 even when the hydraulic pressure is not acting on the hydraulic chamber 42 or when the hydraulic pressure is extremely small.

The hydraulic pump 3 and the control valve mechanism 2 are connected to the first oil passage 1
They are connected by 5. The pressure oil generated by the hydraulic pump 3 is supplied to the control valve mechanism 2 via the first oil passage 15. The second oil passage 16 branched from the first oil passage 15 is connected to an oil hole 70 of the rack housing 11, and the pressure oil is also supplied to the hydraulic chamber 42.

The branch point 17 between the first oil passage 15 and the second oil passage 16
The control valve 7 is provided between the valve shaft 13 and the concave portion 34 of the valve shaft 13 in the control valve mechanism 2, and hydraulic pressure corresponding to the opening of the control valve 7 is generated in the first oil passages 15 and 16.

The valve opening of the control valve 7 is mechanically controlled in conjunction with the driver's steering operation. When the steering angle is small, the valve opening is reduced.
When the steering angle is equal to or greater than a predetermined value, the valve opening is set to be large.

Next, the operation of the present embodiment will be described with reference to FIGS.

4 to 6, V1 and V2 denote recesses 34 of the valve shaft 13 facing the pressure oil holes 26.
V3 and V4 correspond to the gaps 40A and 40B on both sides in the circumferential direction of the concave portion 35 of the valve shaft 13 that does not face the pressure oil hole 26.

When the vehicle travels straight, as shown in FIG. 4, the opening of the control valve 7 is small, so that the hydraulic pump 3
The hydraulic pressure P between the control valve 7 and the control valve 7 is kept high, the hydraulic pressure supplied to the hydraulic chamber 42 is high, and the pressing force F of the rack guide 44 is high, so that the steering stability is high.

At the time of turning, as shown in FIG. 5, the opening of the control valve 7 becomes large, and changes to V1 depending on the turning direction.
And V4 or V2 and V3 are narrowed. At this time, a pressure difference occurs between the two oil chambers of the power cylinder 1, and an assist force is generated in the steering direction. Power cylinder 1 during steering
The pressure oil sent from the pump 3 to move from right to left or from left to right is moved into the piston.

Accordingly, the hydraulic pressure P between the hydraulic pump 3 and the control valve 7 during steering is relatively lower than when the vehicle is traveling straight, and the hydraulic pressure supplied to the hydraulic chamber 42 is relatively lower. For this reason, the pressing force F of the rack guide 44 becomes relatively lower than when the vehicle travels straight, and the frictional resistance between the rack guide 44 and the rack gear 5 is reduced, so that a light steering feeling can be obtained.

During steering, as shown in FIG. 6, the opening of the control valve 7 is large as in steering, and V
Although the gap between 1 and V4 or between V2 and V3 is narrowed, the pressure oil sent from the pump 3 cannot flow into the pinstone because the piston in the power cylinder 1 is stopped.

Accordingly, the hydraulic pressure P between the hydraulic pump 3 and the control valve 7 rises relatively to the time of turning, and the hydraulic pressure P
Is also relatively high. For this reason, the pressing force F of the rack guide 44 becomes relatively higher than when the vehicle is steered, the frictional resistance between the rack guide 44 and the rack gear 5 increases, and the sound of the rack gear 5 and the pinion gear 10 is hit, and the tire It is possible to prevent the occurrence of steering rotational vibration caused by the balance excitation force.

(Embodiment 2) FIG. 7 is a sectional view showing a control valve mechanism of a hydraulic power steering apparatus according to Embodiment 2 corresponding to the second aspect of the present invention, and FIG. FIG. 9 and FIG. 9 are AA cross-sectional views in a steered state.

The second embodiment is different from the hydraulic power steering apparatus of the first embodiment in that the valve shaft 13
Has a projection 60 in the concave portion 34 facing the convex portion 22 in which the pressure oil hole 26 of the valve body 12 is formed.

As shown in FIG. 8, when the valve shaft 13 and the valve body 12 are not rotating relative to each other, the protrusion 60 restricts the opening area of the pressure oil hole to a small value. Increase the hydraulic pressure between. During steering, as shown in FIG.
When the valve body 12 and the valve body 12 rotate relative to each other, the protrusion 60 rotates together with the valve shaft 13, the opening area of the pressure oil hole increases, and the hydraulic pressure from the pump 3 is released.

In the second embodiment, since the control valve 7 is formed between the protrusion 60 provided on the valve shaft 13 and the pressure oil hole 26, the rack guide can be pushed according to the steering state with a simple structure. It is possible to generate pressure.

(Embodiment 3) The configuration of an embodiment 3 corresponding to the invention described in claim 3 will be described with reference to FIG.

In the third embodiment, the control valve 7 is a solenoid valve in the hydraulic power steering apparatus shown in the first embodiment, and the valve opening is controlled by electronic control.

That is, the steering controller 63 includes a steering angle sensor 62 for detecting a steering angle, and controls the opening of the control valve 7 based on a signal from the steering angle sensor 62.
(Valve control means), and the steering controller 63 adjusts the opening degree of the control valve 7 to a small value when the steering angle is small and to a large value when the steering angle is equal to or more than a predetermined value. A pressing force F of 44 is generated.

In this embodiment, since the control valve 7 is constituted by a solenoid valve, the steering angle sensor 6
2, the pressure in the hydraulic chamber 42 can be adjusted immediately when the steering information is detected, so that a light steering feeling can be obtained immediately after the start of steering.

(Embodiment 4) A configuration of an embodiment 4 corresponding to the invention described in claim 4 will be described with reference to FIG.

In the third embodiment, the steering state is detected by the steering angle sensor 62 in the second embodiment, whereas the tie rod axial force sensor 65 for detecting the axial force of the tie rod 64 is used.
Is an example in which is used as an input information sensor. Control valve 7
As shown in FIG. 13, the valve opening control is such that the valve opening is increased as the tie rod axial force (steering force) increases.

In this embodiment, the steering information for controlling the opening and closing of the control valve 7 is represented by the tie rod axial force, so that the steering intention of the driver is reflected most directly, and the steering force which is hardly affected by disturbance is controlled. It can be a parameter of sensing when performing.

The reason is that the steering information can be detected from the steering rotational angular acceleration. However, since the influence of various parameters such as the steering moment of inertia is large, for example, if the steering is replaced, the set value of the control is set. Must be changed, which is inappropriate as a sensing parameter.

Regarding the measurement of the steering force, the steering force can be measured even if the torsional torque is measured by magnetically detecting the rotational angular displacement difference between two torsions on the steering shaft. The steering force is represented by the tie rod axial force measured by a strain sensor that does not have a strain.

(Fifth Embodiment) The structure of a fifth embodiment corresponding to the invention described in claim 5 will be described with reference to FIG.

The fifth embodiment is directed to a hydraulic power steering apparatus according to the third or fourth embodiment,
The vehicle speed sensor 66 is added. As shown in FIG. 14, the valve opening control of the control valve 7 is such that, when it is determined from the steering information that the vehicle is traveling straight, the valve opening becomes smaller as the vehicle speed becomes higher. At the time of turning, for example, as shown in FIG. 13, control for increasing the valve opening degree as the tie rod axial force increases may be used together.

Therefore, in the third embodiment, the degree of stability of steering during high-speed running can be further increased by reducing the opening of the control valve 7 during high-speed running.

[Brief description of the drawings]

FIG. 1 is an overall system diagram showing a hydraulic power steering device according to a first embodiment.

FIG. 2 is a sectional view showing a control valve mechanism of the hydraulic power steering device according to the first embodiment.

FIG. 3 is a sectional view taken along line AA of FIG. 7, illustrating a control valve mechanism of the hydraulic power steering device according to the first embodiment.

FIG. 4 is a hydraulic circuit diagram of the hydraulic power steering device according to the first embodiment when traveling straight ahead.

FIG. 5 is a hydraulic circuit diagram during turning in the hydraulic power steering device according to the first embodiment.

FIG. 6 is a hydraulic circuit diagram of the hydraulic power steering apparatus according to the first embodiment when steering is maintained.

FIG. 7 is a sectional view showing a control valve mechanism of the hydraulic power steering device according to the second embodiment.

FIG. 8 is a sectional view taken along the line AA of FIG. 7, showing a control valve mechanism (at the time of straight traveling) of the hydraulic power steering device according to the second embodiment.

FIG. 9 is a sectional view taken along the line AA of FIG. 7, showing a control valve mechanism (at the time of steering rotation) of the hydraulic power steering device according to the second embodiment.

FIG. 10 is an overall system diagram showing a hydraulic power steering device according to a third embodiment.

FIG. 11 is an overall system diagram showing a hydraulic power steering device according to a fourth embodiment.

FIG. 12 is an overall system diagram showing a hydraulic power steering device according to a fifth embodiment.

FIG. 13 is a characteristic diagram showing a relationship between a tie rod axial force and a valve opening used in valve opening control of a hydraulic power steering device according to a fourth embodiment.

FIG. 14 is a characteristic diagram showing a relationship between a vehicle speed and a valve opening used in valve opening control of a hydraulic power steering device according to a fifth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power cylinder 2 Control valve mechanism 3 Hydraulic pump 4 Reservoir tank 5 Rack gear 6 Retainer 7 Control valve 10 Pinion gear 11 Valve housing 12 Valve body 13 Valve shaft 14 Torsion bar 15 First oil passage 16 Second oil passage 17 Branch point 26 Pressure oil Hole 62 Steering angle sensor 63 Steering controller 64 Tie rod shaft 65 Tie rod axial force sensor 66 Vehicle speed sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B62D 113: 00

Claims (5)

[Claims] 1. A control valve mechanism provided between a hydraulic pump and a reservoir tank for controlling suction and discharge of hydraulic oil to and from a power cylinder, a valve housing of the control valve mechanism,
A valve body connected to the pinion gear so as to be integrally rotatable is disposed so as to be relatively rotatable, and a valve shaft connected to the input shaft is fitted to the valve body so as to be relatively rotatable, and the input shaft is connected via a torsion bar. A hydraulic power steering device connected to the pinion gear, the input shaft and the torsion bar being rotatable relative to each other, and pressing the rack gear against the pinion gear at a fitting portion between the pinion gear and the rack gear; A rack guide that presses toward the rack guide, a spring element that constantly applies a constant pressing force to the rack guide, a preload device that increases the pressing force of the rack guide according to an increase in hydraulic pressure, and connects a hydraulic pump and a control valve mechanism. A first oil passage, and a second oil passage branched from the first oil passage and connected to a preload device. And the control valve mechanism is provided between a branch point of the first oil passage and the second oil passage and the control valve mechanism. When the steering angle of the steering is small, the valve opening degree is small. A hydraulic power steering device, comprising: a control valve that adjusts an amount of oil passing therethrough by increasing a degree of oil flow. 2. The hydraulic power steering apparatus according to claim 1, wherein the control valve mechanism further comprises: a protrusion formed in the valve shaft, the protrusion being provided in a concave portion of the valve body opposite to a convex portion having a pressure oil hole formed in the valve body. A hydraulic power steering device, wherein the protrusion restricts the opening area of the pressure oil hole to be small when the valve shaft and the valve body are not rotating relative to each other. 3. The hydraulic power steering apparatus according to claim 1, wherein a steering angle sensor for detecting a steering angle and an opening degree of the control valve driven by a solenoid are controlled based on a signal from the steering angle sensor. Valve control means, wherein the valve control means is means for adjusting the valve opening degree to be small when the steering angle is small, and to be large when the steering angle is a certain value or more. Hydraulic power steering device. 4. The hydraulic power steering device according to claim 1, wherein a steering force sensor for detecting a tie rod axial force of a tie rod shaft connected to the rack, and an opening degree of the control valve driven by a solenoid. A hydraulic power steering apparatus, comprising: valve control means for controlling based on a signal from the steering force sensor, wherein the valve control means is a means for adjusting the valve opening to be larger as the steering force is larger. 5. The hydraulic power steering apparatus according to claim 3, further comprising a vehicle speed sensor for detecting a vehicle speed, wherein the valve control means determines whether the vehicle speed is higher when the vehicle is running straight ahead. A hydraulic power steering device, characterized in that the opening degree is adjusted to be small.