JP4637630B2 - Power steering device - Google Patents

Description

  The present invention relates to a power steering apparatus including a flow rate control valve that controls a flow rate guided to a power cylinder.

As this type of device, the device described in Patent Document 1 has been conventionally known. FIG. 3 and FIG. 4 show this conventional device. First, the configuration of the entire power steering apparatus will be described with reference to FIG.
A pump P is integrally incorporated in the main body B together with the spool 1 of the flow control valve V.
The spool 1 has one end facing one pilot chamber 2 and the other end facing the other pilot chamber 3. The one pilot chamber 2 is always in communication with the pump P through the pump port 4. A spring 5 is interposed in the other pilot chamber 3. The pilot chambers 2 and 3 thus configured communicate with each other via a variable orifice a that controls the opening degree according to the excitation current I of the solenoid SOL.

That is, one pilot chamber 2 communicates with the inflow side of the steering valve 9 that controls the power cylinder 8 via the flow path 6 → the variable orifice a → the flow path 7. The other pilot chamber 3 communicates with the inflow side of the steering valve 9 via the flow path 10 and the flow path 7.
Therefore, both the pilot chambers 2 and 3 communicate with each other via the variable orifice a, and the pressure on the upstream side of the variable orifice a acts on one pilot chamber, and the pressure on the downstream side acts on the other pilot chamber 3. Will act.

The spool 1 maintains a position where the acting force of one pilot chamber 2 and the acting force of the other pilot chamber 3 are balanced. At the balanced position, the opening degree between the pump port 4 and the tank port 11 is maintained. Is decided.
Now, if the pump drive source 12 which consists of an engine etc. has stopped, pressure oil will not be supplied to the pump port 4. FIG. If no pressure oil is supplied to the pump port 4, no pressure is generated in the pilot chambers 2 and 3, so that the spool 1 maintains the illustrated normal position by the action of the spring 5.

When the pump P is driven from the above state and pressure oil is supplied to the pump port 4, a flow can be made to the variable orifice a, so that a pressure loss occurs there. Due to this pressure loss, a pressure difference is generated between the pilot chambers 2 and 3, and the spool 1 moves against the spring 5 according to the pressure difference and maintains the balance position.
As the spool 1 moves against the spring 5 in this way, the opening degree of the tank port 11 is increased, but the control flow rate guided to the steering valve 9 side according to the opening degree of the tank port 11 at this time A distribution ratio between QP and the return flow rate QT returned to the tank T or the pump P is determined. In other words, the control flow rate QP is determined according to the opening degree of the tank port 11.

  The fact that the control flow rate QP is controlled according to the opening degree of the tank port 11 determined by the moving position of the spool 1 as described above means that the control flow rate QP is finally determined according to the opening degree of the variable orifice a. become. This is because the movement position of the spool 1 is determined by the pressure difference between the pilot chambers 2 and 3, and the opening of the variable orifice a determines this pressure difference.

Therefore, in order to control the control flow rate QP according to the vehicle speed and the steering situation, it is only necessary to control the opening of the variable orifice a, that is, the excitation current of the solenoid SOL.
This is because the opening of the variable orifice a is kept to a minimum when the solenoid SOL is in a non-excited state, and the opening is increased as the exciting current is increased.

  The steering valve 9 controls the supply flow rate to the power cylinder 8 in accordance with an input torque (steering torque) of a steering wheel (not shown). For example, if the steering torque is large, the supply amount to the power cylinder 8 is increased, and if the steering torque is small, the supply flow rate is decreased accordingly. The switching amount of the steering torque and the steering valve 9 is determined by a torsional reaction force such as a torsion bar (not shown).

If the switching amount of the steering valve 9 is increased when the steering torque is large as described above, the assist force by the power cylinder 8 is increased accordingly. On the contrary, if the switching amount of the steering valve 9 is reduced, the assist force is reduced.
If the required (required) flow rate QM of the power cylinder 8 determined by the steering torque and the control flow rate QP determined by the flow control valve V are always equal, the energy loss on the pump P side can be kept low. This is because the energy loss on the pump P side is caused by the difference between the control flow rate QP and the required flow rate QM of the power cylinder 8.

As described above, in order to make the control flow rate QP as close as possible to the required flow rate QM of the power cylinder 8, the opening of the variable orifice a is controlled by the excitation current I for the solenoid SOL, and this excitation current I is controlled. This is the controller C.
A steering angle sensor 16 and a vehicle speed sensor 17 are connected to the controller C, and the excitation current I of the solenoid SOL is controlled based on the output signals of both sensors.

In the figure, reference numeral 18 is a slit formed at the tip of the spool 1, and even when the spool 1 is at the position shown in the figure, one pilot chamber 2 always communicates with the flow path 7 via this slit 18. I am doing so. In other words, even when the spool 1 is in the illustrated state and the flow path 6 is closed, the oil discharged from the pump P is supplied to the steering valve 9 side through the slit 18. ing.
Although the flow rate is very small as described above, the pressure oil is supplied to the steering valve 9 side for the purpose of preventing seizure of the entire apparatus, preventing disturbance such as kickback, and ensuring responsiveness. Because. However, these objects can also be achieved by securing a standby flow rate, which will be described later, and a detailed description will be given later.

  Reference numeral 19 denotes a driver connected between the controller C and the solenoid SOL.

  The control system of the controller C is as shown in FIG. In other words, the steering angle signal from the steering angle sensor 16 and the vehicle speed signal from the vehicle speed sensor 17 are input to the controller C. Then, the controller C calculates the steering angle θ and the steering angular velocity ω from the steering angle signal. The required flow rate QM is estimated based on the steering angle θ and the steering angular velocity ω.

  The steering angle θ and the steering angle current command value I1 in FIG. 4 are determined based on theoretical values in which the relationship between the steering angle θ and the control flow rate QP becomes a linear characteristic. Also, the relationship between the steering angular velocity ω and the steering angular velocity current command value I2 is determined based on a theoretical value in which the steering angular velocity ω and the control flow rate QP are linear characteristics.

However, if the steering angle θ and the steering angular velocity ω do not become a certain set value or more, both the command values I1 and I2 are output as zero. That is, when the steering wheel is neutral or in the vicinity thereof, the command values I1 and I2 are set to zero.
The steering angular current command value I1 for the steering angle θ and the steering angular velocity current command value I2 for the steering angular velocity ω are stored in advance in the controller C as table values.

  Further, the controller C outputs the first vehicle speed related current command value Io1 and the second vehicle speed related current command value Io2 based on the output signal of the vehicle speed sensor 17, and these first vehicle speed related current commands are output. The value Io1 and the second vehicle speed related current command value Io2 are stored in advance in the controller C as table values.

The first vehicle speed related current command value Io1 is set to output 1 in the low speed range and to output, for example, 0.6 in the maximum speed range. Further, the second vehicle speed related current command value Io2 is set to output 1 in the low speed range and to output, for example, 0.8 in the maximum speed range.
That is, the first vehicle speed related current command value Io1 is controlled in the range of 1 to 0.6, while the second vehicle speed related current command value Io2 is controlled in the range of 1 to 0.8. Accordingly, the gain from the low speed range to the maximum speed range is such that the first vehicle speed related current command value Io1 is larger.

  Then, the steering angle current command value I1 based on the steering angle θ is multiplied by the first vehicle speed related current command value Io1. Therefore, the higher the vehicle speed signal V, the smaller the output value that is the multiplication result, that is, the steering angle system current command value Iθ. Moreover, since the gain of the first vehicle speed related current command value Io1 is larger than the gain of the second vehicle speed related current command value Io2, the rate of decrease of the steering angle system current command value Iθ increases as the speed increases. Become.

  On the other hand, for the steering angular velocity current command value I2 based on the steering angular velocity ω, the steering angular velocity system current command value Iω is output with the second vehicle speed related current command value Io2 as a limit value. The steering angular velocity system current command value Iω is also reduced in accordance with the vehicle speed, but the gain is made smaller than the gain of the first vehicle speed related current command value Io1, so the steering angular velocity current command value Iω Is smaller than that in the case of the steering angle system current command value Iθ.

The steering angle system current command value Iθ output as described above is compared with the steering angular velocity system current command value Iω, the large current command value Iθ or Iω is adopted, and the result is used as the solenoid current command value. Output as It.
The reason for adopting the larger one in this way is as follows. In other words, since the steering is rarely operated suddenly at high speed, the steering angular velocity system current command value Iω is small and the steering angular system current command value Iθ is usually large when the steering operation is performed. is there.

  Therefore, when traveling at a high speed, the larger steering angle system current command value Iθ is adopted while using the steering angle as a reference to improve the safety and stability of the steering operation. Moreover, by doing in this way, the higher the traveling speed, the higher the ratio of decreasing the control flow rate QP, and the more energy loss can be achieved.

On the other hand, when the vehicle is traveling at a low speed, the steering is often suddenly operated. Therefore, in many cases, the steering angular velocity is larger. Thus, when the steering angular velocity is large, responsiveness is important.
Therefore, when traveling at a low speed, the steering angular velocity system current command value Iω is adopted while using the steering angular velocity as a reference so as to improve the operability of the steering operation, that is, the responsiveness. In this way, even when the traveling speed is increased to some extent, when the steering is suddenly operated, the control flow rate QP can be sufficiently secured and priority can be given to responsiveness.

Even if the vehicle traveling speed is constant, the steering angular system current command value Iθ may increase or the steering angular speed system current command value Iω may increase. For example, when the steering is steered at a certain angle and the steering is held at the position of the steering angle θ, the steering angular velocity ω becomes zero. In this case, although the vehicle speed is the same, the steering angular velocity system current command value Iω is first large, and the steering angular system current command value Iθ becomes larger after the steering is maintained.
However, in this conventional apparatus, since the larger one of the current command values Iθ and Iω is selected as the solenoid current command value It, the solenoid current command value It can be output under any traveling condition. become.

  If the solenoid current command value It is not output at the time of steering as described above, the control flow rate QP cannot be secured. If the control flow rate QP cannot be ensured, at the time of steering, the power cylinder 8 will move against the drag caused by the self-aligning torque of the vehicle. If the power cylinder 8 moves without maintaining its position in this way, it is impossible to maintain the steering itself.

  However, as described above, the solenoid current command value It, which is the larger value of the steering angle system current command value Iθ and the steering angular velocity system current command value Iω, is always output. The solenoid current command value It can be secured. Therefore, the power required for steering can be maintained.

  On the other hand, the steering may be suddenly operated even when traveling at high speed. At this time, since the steering angular velocity system current command value Iω increases, the current command value Iω is selected, and the selected value is output as the solenoid current command value It. However, since the solenoid current command value It at this time is a value controlled within the range of the limit value of the second vehicle speed related current command value Io2, safety is sufficiently ensured.

The standby current command value Is is added to the solenoid current command value It output as described above.
The standby current command Is is for always supplying a predetermined current to the solenoid SOL of the variable orifice a. Thus, the variable orifice a to which the standby current command value Is is supplied keeps the opening degree constant and secures a constant standby flow rate even if the solenoid current command value It is zero. .

Next, the operation of the conventional apparatus will be described.
While the vehicle is running, a steering angle system current command value Iθ that is a product of the steering angle current command value I1 based on the steering angle and the first vehicle speed related current command value Io1 is output. At the same time, the steering angular velocity current command value I2 based on the steering angular velocity is output with the second vehicle speed related current command value Io2 as a limit value.

Then, the magnitude of the steering angle system current command value Iθ and the steering angular velocity system current command value Iω is determined, and the larger one of the steering angle system current command value Iθ or the steering angular velocity system current command value Iω is selected. Is output as a solenoid current command value It. The standby current command value Is is added to the solenoid current command value It output in this way, and the excitation current I of the solenoid at that time is determined.
The excitation current I of the solenoid is mainly based on the steering angle system current command value Iθ when the vehicle is traveling at high speed, and is mainly based on the steering angular speed system current command value Iω when the vehicle is traveling at low speed.

However, even during low-speed running, the solenoid excitation current I is determined based on the steering angle system current command value Iθ during steering.
Even when the vehicle is traveling at high speed, when the steering is suddenly operated, the excitation current I of the solenoid is determined based on the steering angular velocity system current command value Iω.
JP 2001-260917 A

  The conventional power steering apparatus as described above controls the solenoid current command value I to control the opening of the variable orifice. However, even if the opening of the variable orifice is controlled to be constant, for example, if the engine speed increases, the pump discharge amount increases correspondingly and the supply flow rate to the power cylinder also increases. In other words, the conventional power steering device has a problem that its control characteristics differ depending on the number of revolutions of the engine, and the original energy saving effect cannot be fully exhibited.

  An object of the present invention is to provide a power steering device capable of constant control regardless of the engine speed.

  The present invention assumes the following configuration. That is, according to the present invention, a spool is incorporated in the main body, one end of the spool faces one pilot chamber that is always in communication with the pump port, and the other end of the spool faces the other pilot chamber with a spring interposed. An orifice is provided on the downstream side of the one pilot chamber, and pressure oil is guided to the steering valve that controls the power cylinder through the orifice, while the pressure on the upstream side of the orifice is used as the pilot pressure of the one pilot chamber. The downstream pressure is used as the pilot pressure of the other pilot chamber, and the movement position of the spool is controlled by the pressure balance between the two pilot chambers, and the pump discharge amount is guided to the steering valve side according to the movement position. The control flow rate QP and the return flow rate QT returned to the tank or pump are distributed. The orifice is a variable orifice that controls the opening according to the excitation current I of the solenoid, and a controller that controls the excitation current I of the solenoid of the variable orifice is provided, and the controller includes a steering angle sensor and a vehicle speed. The sensor is connected to calculate or store the steering angle θ and the steering angular velocity ω corresponding to the steering angle from the steering angle sensor, while the controller calculates the steering angle current command value I1 and the steering angular velocity corresponding to the steering angle θ. The steering angular velocity current command value I2 corresponding to ω and the vehicle speed related current command value Io from the vehicle speed sensor are stored or calculated, the electric system current command value I1 corresponding to these steering angles, the current command value I2 corresponding to the steering angular velocity, and The solenoid current command value It is calculated based on the vehicle speed related current command value Io, and the solenoid current command value I It is assumed that the power steering apparatus is configured to control the exciting current I of the solenoid of the variable orifice based on t.

On the premise of the above apparatus, the first invention is that the controller has a function of detecting the rotational speed of the engine or a device linked to the engine, and a correction current command value Ir for changing the gain in accordance with the rotational speed. And a function for storing a standby current command value Is for specifying a standby flow rate, and a correction by multiplying the solenoid current command value It and the standby current command value Is by the correction current command value. And a function of outputting the corrected solenoid current command value and the corrected solenoid current command value as a solenoid excitation current I. The correction current command value Ir is the corrected solenoid excitation command value Ir. The solenoid current command value and the standby power are set so that the current I becomes a value that keeps the control flow rate supplied to the power cylinder constant. Characterized in that it is a value for correcting the command value.

The second invention, the controller comprises a function of adding the standby current instruction value Is to the solenoid current instruction value It, the function of multiplying the correction current command value Ir to these total command value (It + Is), this It is characterized in that it has a function of outputting the calculation result (It + Is) × Ir as the excitation current I of the solenoid .

A third invention is the controller, the function of storing the correction current command value Ir and the first correction current command value Ir1 is divided into a second current command value Ir3, the above solenoid current instruction value It A function for calculating a solenoid current command value (It × Ir1) obtained by multiplying a current command value for correction 1 Ir1 and a current command value Ir2 for multiplying the current command value for standby Is2 by the second current command value for correction (Ir2). The function of calculating (Ir2 × Is), the function of adding these solenoid current command values (It × Ir1) and (Ir2 × Is), and the calculation result (It × Ir1) + (Ir2 × Is) It has a feature in that it has a function of outputting as an exciting current I.

According to the first to third aspects of the invention, the desired control characteristics can always be obtained without being affected by the engine speed, and the energy saving effect can be stably obtained.

  FIG. 1 shows the first embodiment. In the first embodiment, the overall structure is exactly the same as that of the conventional apparatus shown in FIG. Therefore, a detailed description of the overall structure shown in FIG. 3 is omitted, and in the following description, the description of FIG. 3 and the symbols used therein are all incorporated.

  In addition, as is apparent from FIG. 1, the first embodiment is a total obtained by adding the correction current command value Ir based on the engine speed to the solenoid current command value It and the standby current command value Is. The point where the value (It + Is) is multiplied is different from the conventional one, and the others are the same as the conventional one. However, in the following, each component in FIG.

  The control system of the controller C in the first embodiment is as shown in FIG. In other words, the steering angle signal from the steering angle sensor 16 and the vehicle speed signal from the vehicle speed sensor 17 are input to the controller C. Then, the controller C calculates the steering angle θ and the steering angular velocity ω from the steering angle signal. The required flow rate QM is estimated based on the steering angle θ and the steering angular velocity ω.

  The steering angle θ and the steering angle current command value I1 in FIG. 1 are determined based on theoretical values in which the relationship between the steering angle θ and the control flow rate QP is linear. Also, the relationship between the steering angular velocity ω and the steering angular velocity current command value I2 is determined based on a theoretical value in which the steering angular velocity ω and the control flow rate QP are linear characteristics.

However, if the steering angle θ and the steering angular velocity ω do not exceed a certain set value, both the steering angular current command value I1 and the steering angular velocity current command value I2 are set to output zero. That is, when the steering wheel is neutral or in the vicinity thereof, the current command values I1 and I2 are set to zero.
The steering angular current command value I1 for the steering angle θ and the steering angular velocity current command value I2 for the steering angular velocity ω are stored in advance in the controller C as table values. However, in the present invention, the controller C may calculate the current command values I1 and I2 each time.

  Further, the controller C outputs the first vehicle speed related current command value Io1 and the second vehicle speed related current command value Io2 based on the output signal of the vehicle speed sensor 17, and these first vehicle speed related current commands are output. The value Io1 and the second vehicle speed related current command value Io2 are stored in advance in the controller C as table values.

The first vehicle speed related current command value Io1 is set to output 1 in the low speed range and to output, for example, 0.6 in the maximum speed range. Further, the second vehicle speed related current command value Io2 is set to output 1 in the low speed range and to output, for example, 0.8 in the maximum speed range.
That is, the first vehicle speed related current command value Io1 is controlled in the range of 1 to 0.6, while the second vehicle speed related current command value Io2 is controlled in the range of 1 to 0.8. Accordingly, the gain from the low speed range to the maximum speed range is such that the first vehicle speed related current command value Io1 is larger.

  The steering angle current command value I1 based on the steering angle θ is multiplied by the first vehicle speed related current command value Io1 corresponding to the vehicle speed signal V. Therefore, the higher the vehicle speed signal V, the smaller the output value that is the multiplication result, that is, the steering angle system current command value Iθ. Moreover, since the gain of the first vehicle speed related current command value Io1 is larger than the gain of the second vehicle speed related current command value Io2, the rate of decrease of the steering angle system current command value Iθ increases as the speed increases. Become.

  On the other hand, for the steering angular velocity current command value I2 based on the steering angular velocity ω, the steering angular velocity system current command value Iω is output with the second vehicle speed related current command value Io2 corresponding to the vehicle speed as a limit value. The steering angular velocity system current command value Iω is also decreased in accordance with the vehicle speed, but since the gain is smaller than the gain of the first vehicle speed related current command value Io1, the current command value Iω is decreased. The rate is smaller than in the case of the current command value Iθ.

  The steering angle system current command value Iθ output as described above is compared with the steering angular velocity system current command value Iω, and the large current command value Iθ or Iω is output as the solenoid current command value It. Yes. In this way, the larger one is adopted, and the reason is as described above.

Further, the standby current command value Is is added to the solenoid current command value It output as described above.
The standby current command Is is for always supplying a predetermined current to the solenoid SOL of the variable orifice a. Thus, the variable orifice a supplied with the standby current command value Is has its opening degree even if the steering angle θ, the steering angular velocity ω, and the first and second vehicle speed related current command values Io1 and Io2 are zero. As well as a constant standby flow rate.

  On the other hand, in the first embodiment, the controller C outputs the correction current command value Ir based on the output signal of a sensor (not shown) that detects the engine speed. The command value Ir is stored in advance in the controller C as a table value. The correction current command value Ir is set to 1 in the low speed range and to 0.6, for example, in the maximum speed range. That is, the correction current command value Ir is controlled in the range of 1 to 0.6, and the gain decreases as the engine speed increases. Thus, the correction current command value Ir output according to the engine speed is multiplied by the sum of the solenoid current command value It and the standby current command value Is, and the final excitation current I is obtained. It will be calculated. The correction current command value Ir is set so that the control flow rate supplied to the power cylinder remains constant even when the engine speed increases and the pump discharge increases. Is set to a value to correct.

Next, the operation of the first embodiment will be described.
As described above, when the magnitude of the steering angle system current command value Iθ and the steering angular velocity system current command value Iω is determined and the solenoid current command value It is calculated, the standby current command is added to the solenoid current command value It. The value Is is added. The added current command value It + Is is multiplied by the correction current command value Ir, and the result is output as the solenoid exciting current I. The excitation current I calculated in this way is mainly based on the steering angle system current command value Iθ when the vehicle is traveling at high speed, and is mainly based on the steering angular speed system current command value Iω when the vehicle is traveling at low speed. .

  However, even during low-speed running, the solenoid excitation current I is determined based on the steering angle system current command value Iθ during steering. Even when the vehicle is traveling at high speed, when the steering is suddenly operated, the excitation current I of the solenoid is determined based on the steering angular velocity system current command value Iω.

  According to the first embodiment as described above, even if the engine speed increases and the pump discharge amount increases, the value that decreases as the engine speed increases becomes the value (It + Is). Therefore, even if the engine speed increases, the standby flow rate does not increase and a constant value can always be maintained. Therefore, the standby flow rate increases as the engine speed increases or decreases, and the solenoid excitation current I does not increase accordingly, and the control flow rate based on the solenoid excitation current I can be stabilized.

  In the first embodiment, the correction current command value Ir is determined based on the engine speed. However, the correction current command value Ir is not based on the engine speed itself but based on the speed of a device linked to the engine, such as a pump. Thus, the correction current command value Ir may be determined. Further, in the first embodiment, the value of the correction current command value Ir is set to 1 to 0.6, but it is natural that the optimum value can be selected according to the actual vehicle or the like.

  Next, the second embodiment shown in FIG. 2 will be described. In the second embodiment, the controller C stores the correction current command value Ir as a first correction current command value Ir1 and a second current command value Ir3. A solenoid current command value (It × Ir1) obtained by multiplying the solenoid current command value It by the first correction current command value Ir1 is calculated, and the second correction current command value Ir2 is calculated as the standby current command value Is. The solenoid current command value (Ir2 × Is) is calculated by multiplication, and the solenoid current command values (It × Ir1) and (Ir2 × Is) are added. The solenoid current command value It is calculated in the same manner as in the first embodiment based on the steering angle system current command value Iθ and the steering angular velocity system current command value Iω.

  Therefore, next, the first correction current command value Ir1 and the second correction current command value Ir2 will be described. The controller C outputs a first correction current command value Ir1 based on an output signal of a sensor (not shown) that detects the engine speed. The first correction current command value Ir1 is: Pre-stored in the controller C as a table value. In addition to the first correction current command value Ir1, the controller C outputs the second correction current command value Ir2. The second correction current command value Ir2 is also used as a table value. C is stored in advance.

  However, the first correction current command value Ir1 is set to output 1 in the low speed range and to output, for example, 0.7 in the maximum speed range. The second correction current command value Ir2 is set to output 1 in the low speed range and to output, for example, 0.6 in the maximum speed range. Therefore, the first correction current command value Ir1 is controlled in the range of 1 to 0.7, and the gain decreases as the engine speed increases. The second correction current command value Ir2 is controlled in the range of 1 to 0.6, and the gain decreases as the engine speed increases.

  The first correction current command value Ir1 as described above is multiplied by the solenoid current command value It calculated in the same manner as in the first embodiment. Further, the second correction current command value Ir2 is multiplied by the standby current command value Is, and (Ir2 × Is) is added to the (It × Ir1) as the excitation current I of the solenoid. Is output.

  The second embodiment is different from the first embodiment in that, among the correction current command values Ir, the first correction current command value Ir1 is multiplied by the solenoid current command value It and the second correction is used. The current command value Ir2 is multiplied by the standby current command value Is and the result is added. In this way, by multiplying the solenoid current command value It by the correction value, it becomes possible to perform more stable control that is not affected by the pump rotational speed.

  Also in the second embodiment, as in the first embodiment, the first and second correction current command values Ir1 and Ir2 are not the engine speed itself, but the rotation of equipment linked to the engine, such as a pump. You may make it decide based on a number. In the second embodiment, the value of the first correction current command value Ir1 is set to 1 to 0.7 and the second correction current command value Ir2 is set to 1 to 0.6. Naturally, the optimum value can be selected according to the above. Moreover, the first correction current command value Ir1 and the second correction current command value Ir2 may be the same or different as in the second embodiment.

It is explanatory drawing which shows the control system of the controller in 1st Embodiment. It is explanatory drawing which shows the control system of the controller in 2nd Embodiment. It is explanatory drawing which shows the whole structure of the conventional power steering apparatus. It is explanatory drawing which shows the control system of the controller of the conventional power steering apparatus.

Explanation of symbols

I Excitation current of solenoid I1 Steering angular current command value I2 Steering angular velocity current command value Io1 First vehicle speed related current command value Io2 Second vehicle speed related current command value Iθ Steering angular system current command value Iω Steering angular velocity system current command value It Solenoid current Command value QP Control flow rate QT Return flow rate QM Required flow rate (required flow rate)
QS standby flow rate B body 1 spool 2 one pilot chamber 3 other pilot chamber 4 pump port P pump SOL solenoid a variable orifice 8 power cylinder 9 steering valve C controller 16 steering angle sensor 17 vehicle speed sensor T tank

Claims (3)

A spool is incorporated in the main body, one end of this spool faces one pilot chamber that is always in communication with the pump port, and the other end of the spool faces the other pilot chamber with a spring interposed therebetween. An orifice is provided on the downstream side of the cylinder, and pressure oil is guided to the steering valve that controls the power cylinder through the orifice, while the pressure on the upstream side of the orifice is used as the pilot pressure of the one pilot chamber, and the pressure on the downstream side is set. The control position of the spool is controlled by the pilot pressure of the other pilot chamber, and the movement position of the spool is controlled by the pressure balance between the two pilot chambers, and the pump discharge amount to the steering valve side according to the movement position, and the tank Alternatively, the flow rate is distributed to the return flow rate QT to be returned to the pump, and the orifice is A variable orifice that controls the opening degree according to the exciting current I of the noid is provided, and a controller that controls the exciting current I of the solenoid of the variable orifice is provided, and a steering angle sensor and a vehicle speed sensor are connected to the controller. The controller calculates or stores the steering angle θ and the steering angular velocity ω according to the steering angle from the steering angle sensor, while the controller responds to the steering angular current command value I1 and the steering angular velocity ω according to the steering angle θ. The steering angular velocity current command value I2 and the vehicle speed related current command value Io from the vehicle speed sensor are stored or calculated, the electric current command value I1 corresponding to the steering angle, the current command value I2 corresponding to the steering angular velocity, and the vehicle speed related current command. The solenoid current command value It is calculated based on the value Io, and the variable offset is calculated based on the solenoid current command value It. In the power steering apparatus configured to control the excitation current I of the solenoid of the device, the controller has a function of detecting the rotational speed of the engine or a device linked to the engine and a correction for changing the gain according to the rotational speed. A function for storing the current command value Ir, a function for storing the standby current command value Is for specifying the standby flow rate, and the correction current command value to the solenoid current command value It and the standby current command value Is. A function of correcting by multiplying Ir, and a function of outputting as a solenoid excitation current I in consideration of the corrected solenoid current command value and the corrected standby current command value, and the correction current command value Ir is The corrected excitation current I of the solenoid is a value that keeps the control flow rate supplied to the power cylinder constant. Power steering system which is a value for correcting the solenoid current instruction value and a standby current instruction value as.   The controller has a function of adding the standby current command value Is to the solenoid current command value It, a function of multiplying the total command value (It + Is) by a correction current command value Ir, and a calculation result (It + Is) × The power steering apparatus according to claim 1, further comprising a function of outputting Ir as an exciting current I of the solenoid.   The controller has a function of storing the correction current command value Ir separately into a first correction current command value Ir1 and a second correction current command value Ir3, and a first correction current command to the solenoid current command value It. A function of calculating a solenoid current command value (It × Ir1) multiplied by the value Ir1, and a solenoid current command value (Ir2 × Is) by multiplying the standby current command value Is by the second correction current command value Ir2. The function to calculate, the function to add these solenoid current command values (It × Ir1) and (Ir2 × Is), and the calculation result (It × Ir1) + (Ir2 × Is) are output as the excitation current I of the solenoid The power steering device according to claim 1, further comprising a function of:

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