JP2006062464A - Power steering system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid giving a sense of incongruity to a driver as disturbance from a road surface acts on a steering wheel causing shimmy and judder. <P>SOLUTION: Existence of vibration input of the shimmy, the judder, etc. is judged in accordance with a high frequency component by fetching the high frequency component equivalent to the shimmy and the judder from a torque detection signal T from a steering reaction torque sensor 8. Opening of variable throttle valves is contracted in the closing direction when the vibration input is detected in accordance with the torque detection signal T by interposing and inserting the variable throttle valves 57a, 57b respectively in discharge side passages 53a, 53b communicated to each of pressure chambers 5a, 5b of a power cylinder 5. It is possible to avoid transmittance of the disturbance from the road surface to the driver through the steering wheel 1 and to avoid giving of the sense of incongruity to the driver by the disturbance as pulse pressure of working fluid pressure accompanying the vibration input from the road surface is restrained by contracting the variable throttle valves 57a, 57b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power steering device that assists (steering assistance) a force (torque) required for steering by a steering assistance force generated by a power cylinder.

2. Description of the Related Art Conventionally, there has been proposed a power steering device that assists a driver's steering force by means such as hydraulic pressure or an electric motor, and this power steering device improves steering performance by assisting the driver's steering force. It has a function.
In a hydraulic power steering device, by configuring the hydraulic circuit as a closed circuit, the closed circuit part serves as a damper, which is also effective for vibration input that causes kickback, shimmy, etc. There is (for example, Patent Document 1).
Japanese Patent Laid-Open No. 14-145087

However, in the hydraulic power steering device configured as a closed circuit as described above, the only element that suppresses vibration input generated by shimmy and judder is the friction, inertia, etc. of the closed circuit. The input suppression force is reduced. In addition, there is a problem that the vibration frequency that can be suppressed due to variations in components varies depending on the system structural elements.
Accordingly, the present invention has been made paying attention to the above-mentioned conventional unsolved problems, and an object thereof is to provide a power steering device capable of accurately reducing vibration input.

In order to achieve the above object, in the power steering apparatus according to the present invention, the working fluid pressure is supplied to the steering system as a steering assist force by the power cylinder, and the steering assist is performed. At this time, a flow rate adjustment valve is disposed in a closed circuit portion of the fluid pressure circuit communicating with the power cylinder, and the opening degree of the flow rate adjustment valve is adjusted by the adjustment unit according to the detection result of the disturbance detection unit.
Here, the disturbance acting on the steered wheels from the road surface or the like may be transmitted to the steering system via the power cylinder, but when the disturbance is detected by the disturbance detecting means, the flow adjustment valve is throttled to cause the disturbance. Since fluctuations in the working fluid pressure are suppressed, disturbances transmitted to the steering system are suppressed.

  Since the power steering device according to the present invention inserts a flow rate adjusting valve in the communication path communicating with the power cylinder of the fluid pressure circuit, and adjusts the flow rate adjusting valve according to the detection result of the disturbance detecting means, Disturbances acting on the steered wheels from the road surface etc. can be prevented from being transmitted to the steering system via the power cylinder, and avoiding the driver feeling uncomfortable due to the disturbance being transmitted to the steering system Can do.

Embodiments of the present invention will be described below.
First, a first embodiment will be described.
FIG. 1 is a schematic configuration diagram showing an example of a power steering apparatus according to the present invention.
In the figure, reference numeral 1 denotes a steering wheel. The steering wheel 1 is connected to an upper end portion of a steering shaft 2, and the steering shaft 2 extends downward. The lower end portion of the steering shaft 2 is connected to the pinion shaft 3 via a torque detection mechanism. The lower end of the pinion shaft 3, that is, the pinion meshes with a rack 4 disposed in the vehicle width direction, and the rack 4 and the pinion shaft 3 constitute a steering gear. Therefore, the rotational motion around the steering shaft 2 from the steering wheel 1 is converted into the straight motion (translational motion) of the rack 4.

The both ends of the horizontally extending rack 4 are connected to the steered wheels via tie rods (not shown), respectively, and the left and right steered wheels are steered when the rack 4 moves (translates) in the horizontal direction. It is like that.
A power cylinder 5 is linked to the rack 4, and a braking fluid pressure to the left and right pressure chambers 5 a and 5 b formed in the power cylinder 5 is controlled by a hydraulic circuit 6.

  The hydraulic circuit 6 is formed as an actuator unit incorporated in one unit, and includes a gear pump 52 driven by a motor 51, as shown in FIG. And a pair of discharge ports 52a and 52b, one of which is a discharge side and the other of which is a suction side during forward rotation and reverse rotation. The discharge ports 52a and 52b are connected to left and right pressure chambers 5a and 5b formed in the power cylinder 5 via discharge side communication passages 53a and 53b, respectively.

The discharge side communication passages 53a and 53b are connected to reservoir tanks 55a and 55b via oil supply passages 54a and 54b, respectively, and these oil supply passages 54a and 54b are connected to the discharge side from the reservoir tanks 55a and 55b. Check valves 56a and 56b are inserted in such a state that only replenishment of oil in the direction of the communication passages 53a and 53b is possible.
Moreover, variable throttle valves 57a and 57b are inserted in the discharge side communication passages 53a and 53b, respectively. The discharge side communication passages 53a and 53b are connected to each other on the downstream side of the variable throttle valves 57a and 57b, that is, on the power cylinder 5 side, by a bypass passage 58. A fail safe valve 59 for opening and closing the path 58 is inserted.

Further, the upstream side of the variable throttle valves 57a, 57b of the discharge side communication passages 53a, 53b is connected to a relief valve 60, and the relief valve 60 and the discharge side communication passages 53a, 53b are arranged in the direction of the relief valve 60. The check valves 61a and 61b are inserted in a state in which only the inflow is possible.
Then, by rotating the motor 51 forward or backward, one of the pair of discharge ports 52a and 52b of the gear pump 52 becomes the discharge side and the other becomes the suction side, and only the fluid pressure of the one discharge side communication passages 53a and 53b. As a result, the fluid pressure acting on the pressure chamber 5a or 5b is increased, thereby causing the rack 4 to translate in one direction to generate a steering assist force.

  Further, when the steering assist is not performed, the fail safe valve 59 is opened and the pressure chambers 5a and 5b of the power cylinder 5 are communicated to stop the generation of the steering assist force and to generate the steering assist force. In order to avoid the steering assisting force acting on the steering operation of the steering wheel 1 to the extent that there is no problem, or the output of the power cylinder 5 acting in a direction that impedes the rotation of the steering wheel 1 accompanying steering. It has become.

  The torque detection mechanism includes a torsion bar (not shown) for connecting the lower end portion of the steering shaft 2 and the upper end portion of the pinion shaft 3 and a steering reaction force torque sensor 8 disposed on the outer periphery thereof. The steering reaction torque sensor 8 detects a steering reaction torque from the torsion amount of the torsion bar, and supplies a torque detection signal T corresponding to the magnitude of the steering reaction torque to the control unit 10.

  Further, as shown in FIG. 2, the vehicle is equipped with a travel speed sensor 11. The travel speed sensor 11 detects the travel speed of the host vehicle and detects the travel speed according to the magnitude of the travel speed. The value is supplied to the control unit 10. The steering wheel 1 is provided with a steering angle sensor 12 for detecting the steering angle, and the detected value is also supplied to the control unit 10. The vehicle is also provided with an engine rotation speed sensor 13 for detecting the rotation speed of the engine, a lateral acceleration sensor 14 for detecting the lateral acceleration generated in the vehicle, and a yaw rate sensor 15 for detecting the yaw rate generated in the vehicle. The detected values are also supplied to the control unit 10. The control unit 10 controls the motor 51 and the fail safe valve 59 to generate a steering assist force based on detection signals from various sensors, and adjusts the throttle amounts of the variable throttle valves 57a and 57b. It is like that.

FIG. 2 is a block diagram illustrating a functional configuration of the control unit 10.
Detection signals from various sensors are input to the steering assist control unit 21. The steering assist control unit 21 calculates the necessity of generating the steering assist force and the amount of steering assist force to be generated by a known procedure. In response to these, the valve control unit 22 controls the fail-safe valve 59 to open and close. That is, when the steering assist force is generated, the fail safe valve 59 is controlled to be closed, and when the steering assist force is not generated, the fail safe valve 59 is controlled to be opened. Further, the steering assist control unit 21 generates the steering assist force only when the monitoring result of the abnormality monitoring processing unit 25 that monitors the operating state of the power steering apparatus is normal, and when the abnormality is detected, the steering assist force is generated. Do not generate.

The motor control unit 23 drives and controls the motor 51 so as to generate a fluid pressure that can generate the steering assist force calculated by the steering assist control unit 21.
Further, the torque detection signal T from the steering reaction torque sensor 8 is input to the vibration input detection unit 27 via the band pass filter 26 for detecting a high frequency component. The band-pass filter 26 is a high-pass filter corresponding to shimmy or judder and capable of passing a high frequency component of about 10 to 20 [Hz]. The vibration input detection unit 27 detects the presence or absence of vibration input from the steered wheels generated by shimmy or judder based on the torque detection signal T ′ after the filter processing. That is, when the torque detection signal T includes a high frequency component that generates shimmy or judder, it is determined that there is a vibration input.

The detection result of the vibration input by the vibration input detection unit 27 is input to the valve control unit 28. When there is a vibration input, the valve control unit 28 throttles the opening of the variable throttle valves 57a and 57b. As a result, the change in the pulsating pressure of the fluid pressure in the hydraulic circuit 6 is suppressed. Conversely, when there is no vibration input, the variable throttle valves 57a and 57b are controlled to be opened.
Next, the operation of the first embodiment will be described with reference to a flowchart shown in FIG. 3 showing a processing procedure of vibration input suppression processing for controlling the variable throttle valves 57a and 57b according to vibration input. In addition, this vibration input suppression process is performed by the interruption process of the predetermined period set beforehand.

Assuming that the host vehicle is traveling straight ahead and steering is not being performed, the torque detection signal T detected by the steering reaction torque sensor 8 is substantially zero in this state, and generates a steering assist force. Since there is no need, the motor 51 is not driven. Therefore, the steering assist force by the power cylinder 5 is not generated.
From this state, when the driver performs a steering operation, a torque detection signal T corresponding to the torsion amount of the torsion bar is detected, the motor 51 is driven to rotate according to the torque detection signal T, and the fail safe valve 59 is The closed state is controlled, whereby the working fluid pressure acting on one of the pressure chambers 5a or 5b of the power cylinder 5 is increased, and a steering assist force corresponding to the torque detection signal T is generated.

At this time, in the vibration input suppression process, as shown in FIG. 3, when the torque detection signal T of the steering reaction force torque sensor 8 is read, the process proceeds from step S <b> 1 to step S <b> 2. Process.
Here, when shimmy, judder or the like is generated, a high frequency component is included in the torque detection signal T detected by the steering reaction force torque sensor 8, and therefore the torque detection signal T after the high-pass filter processing. A high frequency component appears at ′, and it can be considered that there is a vibration input that generates shimmy, judder or the like (step S3).

Therefore, since there is a vibration input and the variable throttle valves 57a and 57b need to be controlled in the closing direction, the process proceeds from step S4 to step S5, and the throttle amounts of the variable throttle valves 57a and 57b are determined. This aperture amount is determined based on, for example, the magnitude of fluctuation of the filtered torque detection signal T ′. For example, it is determined that the vibration input is larger as the fluctuation is larger, and the aperture amount is increased.
Then, the opening degree of the variable throttle valves 57a and 57b is controlled in the closing direction so as to achieve the throttle amount determined in this way (step S6). Then, the vibration input suppression process ends.
As a result, in FIG. 1, the opening degree of the variable throttle valves 57a and 57b is throttled in the closing direction. Therefore, even if there is vibration input from the steered wheels, the hydraulic circuit is controlled by throttling the variable throttle valves 57a and 57b. The pulse pressure change in 6 is suppressed.

  Therefore, it is possible to avoid the vibration input from the steered wheels being transmitted to the steering wheel 1 via the steering shaft 2, and when there is a vibration input generated by shimmy or judder, this is transmitted to the steering wheel 1. Can be avoided. As a result, it is possible to avoid the occurrence of shimmy, judder, and the like, and to avoid giving the driver an uncomfortable feeling due to the occurrence of shimmy, judder, or the like.

Thus, when the shimmy or judder is not detected from the state in which the vibration input such as shimmy or judder is detected, the filtered torque detection signal T ′ does not include a high frequency component. It is determined that there is no vibration input.
When there is no vibration input, it is not necessary to throttle the opening of the variable throttle valves 57a and 57b, so the routine proceeds from step S4 to step S7, and the opening of the variable throttle valves 57a and 57b is controlled to be in the open state. Therefore, the opening degree of the variable throttle valves 57a and 57b is not reduced unnecessarily, and the opening degree of the variable throttle valves 57a and 57b is controlled in the closing direction. The responsiveness of the working fluid pressure acting on the cylinder 5 is reduced, so that it is possible to avoid the responsiveness from being lowered when the steering assist force is generated.

  At this time, the vibration input for generating shimmy, judder and the like is detected by the steering reaction force torque sensor 8, and the existing sensor already mounted on the power steering apparatus is used. Therefore, it is not necessary to newly provide a sensor for detecting vibration input, and it can be realized simply by providing the variable throttle valves 57a and 57b. Therefore, it can be easily realized without significant change of the power steering device. can do.

At this time, the variable throttle valves 57a and 57b are provided in the discharge side communication passages 53a and 53b that connect the left and right pressure chambers 5a and 5b of the power cylinder 5 and the discharge ports 52a and 52b of the gear pump 52, respectively. Therefore, even when either the right steering or the left steering is performed, the discharge side communication passages 53a and 53b communicating with the pressure chambers 5a and 5b have the greatest influence of the fluctuation of the pulse pressure due to the vibration input from the road surface. Fluctuations in the pressure can be suppressed, and transmission of vibration input to the steering wheel 1 can be effectively and reliably suppressed.
Further, since the variable throttle valves 57a and 57b are provided on the upstream side of the fail-safe valve 59 and the gear pump 52 side, the variable throttle valves 57a and 57b can be incorporated in an actuator unit including the hydraulic circuit 6. it can.

  In the first embodiment, the variable throttle valves 57a and 57b are provided on the upstream side of the fail-safe valve 59 in the discharge side communication passages 53a and 53b. However, the present invention is not limited to this. For example, it may be inserted at any position of the discharge side communication passages 53a and 53b. For example, as shown in FIG. 4, it may be provided in the discharge side communication passages 53a and 53b on the downstream side of the fail safe valve 59. In this case, it is provided outside the actuator unit integrally formed as a hydraulic circuit. May be. Thus, when the variable throttle valves 57a and 57b are integrally formed as the actuator unit or formed separately from the actuator unit, when mounted on the vehicle, the variable throttle valves 57a and 57b are provided according to the arrangement of the peripheral components. Can respond to changes.

  In the above-described embodiment, the case where the variable throttle valves 57a and 57b are provided in the discharge side communication passages 53a and 53b has been described. However, it is not always necessary to provide the variable throttle valves 57a and 57b in the discharge side communication passages 53a and 53b. . However, as described above, the vibration input transmitted to the driver can be more effectively reduced by providing the discharge side communication passages 53a and 53b respectively. Further, it is not always necessary to provide the discharge side communication passages 53a and 53b, and one or a plurality of them may be provided at any position of the closed circuit portion communicating with the power cylinder 5.

Next, a second embodiment of the present invention will be described.
Since the second embodiment is the same as the first embodiment except that the functional configuration of the control unit 10 is different, the same reference numerals are given to the same parts, and detailed descriptions thereof are omitted. .
FIG. 5 is a block diagram showing a functional configuration of the control unit 10 in the second embodiment. In the second embodiment, an accelerator opening sensor 16 for detecting the accelerator opening and a driving force detecting means 17 for detecting the engine driving force are further provided.

  Then, as shown in FIG. 5, the control unit 10 in the second embodiment is a steering assist control that generates a steering assist force based on detection signals of various sensors, as in the first embodiment. Unit 21, valve control unit 22, motor control unit 23, and abnormality monitoring processing unit 25. A torque steer detection unit 31 that estimates whether torque steer is generated based on detection signals from the travel speed sensor 11, the accelerator opening sensor 17, and the driving force detection means 17, and the torque steer detection unit 30 generates torque steer. When it is presumed to occur, a valve control unit 32 that controls the opening degree of the variable throttle valves 57a and 57b in the throttle direction is provided.

Next, the operation of the second embodiment will be described with reference to a flowchart shown in FIG. 6 showing a processing procedure of torque steer suppression processing for controlling the variable throttle valves 57a and 57b in accordance with torque steer. This torque steer suppression process is executed by an interrupt process with a predetermined cycle set in advance.
Assuming that the host vehicle is stopped and steering is not being performed, the torque detection signal T detected by the steering reaction torque sensor 8 is substantially zero in this state, and generates a steering assist force. Since there is no need, the motor 51 is not driven and the steering assist force by the power cylinder 5 is not generated. Then, when the host vehicle starts and the driver steers and the torque detection signal T increases accordingly, the motor 51 is operated to generate a steering assist force according to the torque detection signal T. A steering assist force corresponding to the torque detection signal T is generated.

At this time, in the torque steer suppression processing of FIG. 6, the process proceeds from step S11 to step S12, and the occurrence of torque steer is determined based on the detection signals from the travel speed sensor 11, the accelerator opening sensor 16, and the driving force detection means 17. Presence / absence and size are estimated.
Here, the torque steer is detected when the accelerator opening detected by the accelerator opening sensor 16 is smaller than a threshold (for example, about 60%) or when the traveling speed detected by the traveling speed sensor 11 is a threshold ( For example, when it is smaller than about 10 km / h, it can be considered that there is almost no possibility of torque steer. Further, it can be predicted that a larger torque steer occurs as the driving force increases. Therefore, the accelerator opening and travel speed conditions when torque steer occurs, and the relationship between the driving force and the torque steer size are obtained in advance through experiments, etc., and the current accelerator opening detected by various sensors. Further, the presence or absence of torque steer may be determined based on the traveling speed, and the torque steer corresponding to the current driving force may be specified.

  At this time, for example, when the driver greatly depresses the accelerator pedal and starts, and when it is determined that the estimated torque steer needs to be suppressed more than, for example, a preset threshold value, The process proceeds from step S13 to step S14, and the throttle amounts of the variable throttle valves 57a and 57b are determined according to the estimated magnitude of torque steer. For example, the throttle amount is increased as the torque steer is larger, and the pulse pressure due to torque steer is further suppressed.

Then, the opening amounts of the variable throttle valves 57a and 57b are controlled in the throttle direction by the amount corresponding to the throttle amount set in step S14 (step S15). Then, the torque steer suppression process ends.
Accordingly, in FIG. 1, since the opening degree of the variable throttle valves 57a, 57b is throttled in the closing direction, even if torque steer is generated at the time of starting and this is input from the steered wheels, the variable throttles By restricting the valves 57a and 57b, fluid pressure fluctuations in the hydraulic circuit 6 are suppressed, so that torque steer input from the steered wheels is prevented from being transmitted to the steering wheel 1 via the steering shaft 2. be able to. Therefore, in a situation where torque steer is input, it can be avoided that this is transmitted to the steering wheel 1, and it can be avoided that the driver feels uncomfortable due to the action of torque steer.

  On the other hand, as described above, when the amount of depression of the accelerator pedal is released from the state where torque steer is predicted to occur or when it is predicted that torque steer will not occur, the variable throttle valve 57a. , 57b need not be throttled, the process proceeds from step S13 to step S16, and the opening degree of the variable throttle valves 57a, 57b is controlled to the open state. Therefore, it is possible to avoid unnecessarily controlling the opening degree of the variable throttle valves 57a and 57b in the throttle direction.

Therefore, in the second embodiment, it is possible to obtain the same effect as that of the first embodiment with respect to torque steer.
In addition, as described above, the second embodiment that performs the suppression process for torque steer and the first embodiment that performs the suppression process for vibration input that generates shimmy, judder, and the like are combined to provide only torque steer. It is also possible to suppress vibration input.

Next, a third embodiment of the present invention will be described.
The third embodiment is the same as the second embodiment except that the processing procedure of the torque steer suppression process in the control unit 10 is different from the second embodiment. Detailed description of the portion is omitted.
FIG. 7 is a flowchart illustrating an example of a processing procedure of torque steer suppression processing according to the third embodiment.
First, in step S21, it is determined whether or not an abnormality has been detected in the monitoring process by the abnormality monitoring processing unit 25. If no abnormality is detected, the process proceeds to step S22, and the torque steer suppression control is performed according to the flowchart of the torque steer suppression process in the second embodiment shown in FIG. Then, the variable throttle valves 57a and 57b are controlled in the throttle direction to suppress torque steer. On the other hand, when an abnormality is detected in the monitoring process by the abnormality monitoring processing unit 25, the process proceeds from step S21 to step S23, and the variable throttle valves 57a and 57b are controlled to be opened.

Here, when an abnormality is detected, in the steering assist control process, the fail safe valve 59 is controlled to be in an open state so as to stop the generation of the steering assist force as described above, and the operation of the motor 51 is stopped. Control is performed so that the working fluid pressure acting on the power cylinder 5 decreases.
At this time, since the variable throttle valves 57a and 57b are controlled to be in the open state in the torque steer suppression process, the variable throttle valves 57a and 57b act in a direction that prevents the return of the working fluid pressure to the reservoir side. This can be avoided, and the generation of the steering assist force can be quickly terminated. When the abnormality is detected, the variable throttle valves 57a and 57b are controlled to be in an open state, and the circuit configuration is the same as when the variable throttle valves 57a and 57b are not provided. There is no need to do so, and processing at the time of abnormality detection can be performed by the same processing procedure as before.

  In the third embodiment, the case where the present invention is applied to the second embodiment has been described. However, the present invention is not limited to this, and the present invention can also be applied to the first embodiment. In other words, when an abnormality is detected when the vibration input suppression process is being executed, the steering assist force generated by the power cylinder 5 is quickly increased by controlling the variable throttle valves 57a and 57b to be open. Can be reduced.

  In each of the above embodiments, shimmy, judder, or torque steer is prevented from being transmitted to the driver via the steering wheel 1; however, the present invention is not limited to this. For example, a frequency component of vibration corresponding to kickback is extracted, and based on this, an uncomfortable feeling given to the driver by kickback is avoided. It is also possible.

  In each of the above-described embodiments, even when the steering assist force is generated, when the vibration input or torque steer input that generates shimmy or judder is detected, the opening of the variable throttle valves 57a and 57b is set. Although the description has been given of the case where the throttle is throttled, when the steering assist force is generated, that is, when the steering wheel 1 is being steered, the variable throttle valves 57a and 57b are opened with priority given to the generation of the steering assist force. It is also possible to ensure quick response of the steering assist force.

Here, in each of the above embodiments, the hydraulic circuit 6 corresponds to the fluid pressure circuit, the variable throttle valves 57a and 57b correspond to the flow rate adjustment valve, and the fail safe valve 59 corresponds to the bypass means. 2 or 5 corresponds to the monitoring means.
In the first embodiment, the processing from step S1 to step S3 in FIG. 3 corresponds to the disturbance detection means, the processing from step S2 corresponds to the filter processing means, and the processing from step S4 to step S7 is the adjustment means. The steering reaction force torque sensor 8 corresponds to the torque detecting means.
In the second embodiment, the processes in steps S11 and S12 in FIG. 6 correspond to the disturbance detecting means, and the processes in steps S13 to S16 correspond to the adjusting means.

It is a schematic structure figure showing an example of a power steering device to which the present invention is applied. It is a block diagram which shows the function structure of the control unit of FIG. It is a flowchart which shows an example of the process sequence of a vibration input suppression process. It is a schematic block diagram which shows the other example of a power steering apparatus. It is a block diagram which shows the function structure of the control unit in 2nd Embodiment. It is a flowchart which shows an example of the process sequence of a torque steer suppression process. It is a flowchart which shows an example of the process sequence of the control unit in 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering wheel 3 Pinion shaft 4 Rack 5 Power cylinder 5a, 5b Pressure chamber 6 Hydraulic circuit 8 Steering reaction force torque sensor 10 Control unit 11 Running speed sensor 12 Steering angle sensor 13 Engine rotational speed sensor 14 Lateral acceleration sensor 15 Yaw rate sensor 16 Accelerator Opening sensor 17 Driving force detection means 51 Motor 52 Gear pumps 53a, 53b Discharge side communication passage 57a 57b Variable throttle valve 59 Fail-safe valve

Claims (8)

A power cylinder that supplies the working fluid pressure to the steering system as a steering assist force in the steering direction;
In a power steering device comprising a fluid pressure circuit for supplying a working fluid pressure to the power cylinder,
A flow rate adjusting valve disposed in a closed circuit portion communicating with the power cylinder of the fluid pressure circuit;
Disturbance detection means for detecting disturbance acting on the steered wheels;
A power steering apparatus comprising: adjusting means for adjusting the opening of the flow rate adjusting valve according to a detection result of the disturbance detecting means.   2. The power steering apparatus according to claim 1, wherein when the disturbance is detected by the disturbance detection means, the adjustment means throttles the opening of the flow rate adjustment valve. Comprising monitoring means for monitoring the operating state of the power steering device;
The power steering apparatus according to claim 1 or 2, wherein the adjusting means controls the flow rate adjusting valve to be opened when an abnormality is detected by the monitoring means. Torque detection means for detecting torque input to the steering system and outputting a detection signal corresponding to the magnitude of the torque,
4. The disturbance detection unit detects a vibration input in a preset frequency range based on a torque detection signal detected by the torque detection unit. The power steering device according to claim 1.   5. The power steering apparatus according to claim 1, wherein the disturbance detection unit detects torque steer. 6. The power cylinder includes two pressure chambers, and generates the steering assist force by applying the working fluid pressure to any one of the pressure chambers.
The power steering according to any one of claims 1 to 5, wherein the flow rate adjusting valve is inserted in each of communication paths communicating with the two pressure chambers of the fluid pressure circuit. apparatus. The power cylinder has two pressure chambers;
The fluid pressure circuit includes a bypass unit that bypasses between the two pressure chambers when an abnormality is detected by a monitoring unit that monitors an operation state of the power steering device.
The power according to any one of claims 1 to 6, wherein the flow rate adjusting valve is provided on the upstream side of the bypass means and is incorporated in one unit together with the fluid pressure circuit. Steering device. The fluid pressure circuit is formed in a unit,
The power steering apparatus according to any one of claims 1 to 6, wherein the flow rate adjusting valve is inserted in a pipe that communicates the unit and the power cylinder.

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