JPH0692257A - Hydraulic power steering device - Google Patents

Abstract

PURPOSE:To provide a hydraulic power steering allowing the direction and grade of auxiliary steering force to be set appropriately by adjusting the supply of operating oil to a power cylinder means through an electronic control means. CONSTITUTION:On the basis of at least steering torque (TS) detected by a steering torque detecting means 3, a control means 13 gives a command 13a for switching the energizing direction and energizing force of a power cylinder means 9 to a motor 11, an actuator. An oil passage switching means 10 is then operated through the motor 11 to control the direction and grade of auxiliary steering force supplied from the power cylinder 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronically controlled hydraulic power steering device capable of freely setting the direction and magnitude of an auxiliary steering force.

[0002]

2. Description of the Related Art A conventional hydraulic power steering device has a structure in which an oil passage is mechanically switched according to an operation of a steering handle. For example, a hydraulic power steering device using a rotary valve mechanism is disclosed in Japanese Patent Laid-Open No.
No. 8-99568.

[0003]

As described above, since the conventional hydraulic power steering device is configured to mechanically switch the oil passage in response to the operation of the steering handle, the relationship between the direction and the magnitude of the auxiliary steering force. Is constant, and it is possible to supply auxiliary power for road load,
It was difficult to control other altitudes.

The present invention has been made to solve such a problem, and the direction and magnitude of the auxiliary steering force are appropriately adjusted by adjusting the supply of hydraulic oil to the power cylinder means through the electronic control means. An object of the present invention is to provide a hydraulic power steering device that can be set.

[0005]

In order to solve the above-mentioned problems, a hydraulic power steering system according to a first aspect of the present invention is directed to a steering torque detecting means for detecting a steering torque input to a steering wheel and a steering wheel for a wheel. Power cylinder means for urging an assisting force by means of the power cylinder means, hydraulic pump means serving as a hydraulic pressure source for the power cylinder means, oil passage switching means for switching the urging direction and urging force of the power cylinder means, and the oil passage switching means are operated. A motor and a control unit that controls the motor based on at least the steering torque detected by the steering torque detection unit are provided.

A hydraulic power steering system according to a second aspect of the present invention comprises a steering torque detecting means for detecting a steering torque input to a steering wheel, and a power cylinder means for urging an assisting force for turning a wheel. Hydraulic pump means serving as a hydraulic pressure source of the power cylinder means, oil passage switching means for switching the urging direction and urging force of the power cylinder means, a motor for operating the oil passage switching means, and a steering torque detected by the steering torque detecting means. Target steering torque setting means for setting a target steering torque based on the above, and control means for controlling the motor according to the set target steering torque.

A hydraulic power steering system according to a third aspect of the present invention is a steering torque detecting means for detecting a steering torque input to a steering handle, a steering angle detecting means for detecting a steering angle of the steering handle, and a wheel steering. A power cylinder means for urging an assisting force to the engine, a hydraulic pump means serving as a hydraulic pressure source for the power cylinder means, an oil passage switching means for switching the urging direction and urging force of the power cylinder means, and an oil passage switching means. A motor for operating and a target steering torque setting means for setting a target steering torque based on a detection signal from the steering angle detection means are provided, and the target steering torque set by the target torque setting means and the steering detected by the steering torque detection means are provided. And a control means for controlling the motor based on the deviation from the torque.

According to another aspect of the hydraulic power steering apparatus of the present invention, steering torque detecting means for detecting a steering torque input to the steering wheel, lateral acceleration detecting means for detecting a lateral acceleration of the vehicle, and steering wheels. Power cylinder means for urging an assisting force, hydraulic pump means serving as a hydraulic pressure source of the power cylinder means, oil passage switching means for switching the urging direction and urging force of the power cylinder means, and oil passage switching means are operated. And a target steering torque setting means for setting a target steering torque based on a detection signal from the lateral acceleration detecting means, and the target steering torque set by the target torque setting means and the steering torque detected by the steering torque detecting means. And a control means for controlling the motor based on the deviation from

A hydraulic power steering apparatus according to a fifth aspect of the present invention relates to steering torque detecting means for detecting a steering torque input to a steering wheel, yaw rate detecting means for detecting a yaw rate of a vehicle, and steering of wheels. A power cylinder means for urging an assisting force, a hydraulic pump means serving as a hydraulic pressure source for the power cylinder means, an oil passage switching means for switching the urging direction and urging force of the power cylinder means, and a motor for operating the oil passage switching means. And a target steering torque setting means for setting a target steering torque based on a detection signal from the yaw rate detecting means, and a deviation between the target steering torque set by the target torque setting means and the steering torque detected by the steering torque detecting means. And a control means for controlling the motor based on the above.

[0010]

The control means of the hydraulic power steering apparatus according to the first aspect operates the motor based on at least the steering torque detected by the steering torque detecting means to drive the oil passage switching means. Therefore, the direction and magnitude of the auxiliary steering force can be freely set.

The control means of the hydraulic power steering apparatus according to the second aspect sets a target steering torque based on the steering torque detected by the steering torque detecting means, and operates the motor based on the set steering torque to operate the oil passage. Drive the switching means. Therefore, by appropriately setting the characteristics of the target steering torque setting means in the control means, it is possible to freely set the direction and magnitude of the auxiliary steering force.

The control means of the hydraulic power steering apparatus according to the third aspect sets the target steering torque corresponding to the steering angle based on the detection signal from the steering angle detection means, and the target torque and steering torque detection means A deviation from the detected steering torque is obtained, and the motor is operated based on the deviation to control the oil passage switching means. Therefore, the steering torque according to the steering angle can be supplied.

Since the control means of the hydraulic power steering apparatus according to the fourth aspect is configured to apply the auxiliary steering force based on the lateral acceleration G of the vehicle and the steering torque (TS), the reaction force against the lateral acceleration is applied. Can be given.

Since the control means of the hydraulic power steering apparatus according to the fifth aspect is configured to apply the auxiliary steering force based on the yaw rate and steering torque of the vehicle, it is possible to apply a reaction force to the yaw rate.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram of a hydraulic power steering apparatus according to claims 1 and 2.

A hydraulic power steering apparatus A according to claims 1 and 2 is formed with a steering torque detecting means 3 provided on a steering shaft 2 connected to a steering handle 1, a pinion gear 4a and a rack shaft 5. A rack and pinion mechanism 4 formed by meshing with the rack teeth 4b,
A tie rod 7 and a knuckle 8 for steering the steered wheels 6 according to the axial movement of the rack shaft 5, a power cylinder means 9 for supplying an auxiliary steering force to the rack shaft 5, an L port of the power cylinder means 9, and An oil passage switching means 10 for adjusting the amount of oil supplied to the R port and an oil pressure, a motor 11 for operating the oil passage switching means 10, a hydraulic pump means 12 for supplying pressure oil, and an oil tank 12a,
The control means 13 outputs a drive command 13a for switching the oil passage and specifying the hydraulic pressure to the motor 11 based on the steering torque 3a detected by the steering torque detecting means 3.

The power cylinder means 9 comprises a piston 9a provided integrally with the rack shaft 5 and a substantially cylindrical cylinder 9b. The cylinder 9 is supplied with pressure oil from the hydraulic pump means 12 via the oil passage switching means 10, and thereby applies thrust to the rack shaft 5. The oil passage switching means 10 uses the motor 11 as an actuator and is drive-controlled via the control device 13 based on the signal 3a from the steering torque detecting means 3.

FIG. 2 is a structural diagram showing a specific example of the steering torque detecting means. 2 (a) is a partial cross section, FIG. 2 (b).
Shows a horizontal section of the shaft. 2a is a torsion bar, 3a
Is an interface circuit, 3b is a differential transformer, and 3c is a core. FIG. 3 is an explanatory diagram showing the operation and detection output characteristics of the steering torque detecting means shown in FIG. Figure 3
3A shows the operation of the steering torque detecting means, and FIG. 3B shows the detection output characteristic.

As shown in FIGS. 2 and 3, in the steering torque detecting means 2, the position of the core 3c of the differential transformer 3b is raised or lowered according to the turning direction of the steering wheel 1 and the steering force. FIG. 3 (a1) shows a steering wheel 1
Is rotated to the right, FIG. 3 (a2) shows a state in which the steering handle 1 is at the neutral position, and FIG.
Shows respective cases where the steering wheel 1 is rotated to the left. As shown in FIG. 3B, an AC signal is supplied to the primary winding 3b1 of the differential transformer 3b,
Since the output induced in each of the windings 3b2 and 3b3 on the secondary side is taken out through the interface circuit 3a provided with a differential amplifier or the like, a DC voltage output can be obtained according to the steering torque.

FIG. 4 is a structural diagram of the oil passage switching means. Figure 4
FIG. 4A shows a non-operating state, and FIG. 4B shows an operating state. The oil passage switching means 10 is configured to control the moving direction and the moving amount of the spool 10a based on the polarity and the current value of the current supplied to the motor 11. The spool position (neutral state) when the motor 11 is not energized is regulated by the biasing means 10b such as a spring, and the opening degrees of the L port and the R port are set to be equal in this neutral state. The openings of the L port and the R port are differentially changed with the movement of the spool 10a.

Therefore, when the spool 10a is moved leftward in the drawing to widen the opening on the R port side as shown in FIG. 4B, pressure oil is applied to the right chamber side of the power cylinder means 9 shown in FIG. Is supplied and the pressure oil in the left chamber is returned to the oil tank 12, the piston 9a generates a steering assist force. The direction and magnitude of the steering assist force are the moving direction and the moving amount of the spool 10a of the oil passage switching means 10, that is,
It is controlled by the polarity of the current supplied to the motor 11 and the current value.

FIG. 5 is a block diagram of the control device.
The control means 13 includes a target steering torque setting means 14 and
Drive means 15. Target steering torque setting means 14
Is the steering torque (T
The signal 14a relating to the auxiliary steering torque value Th supplied from the power cylinder means 9 is generated and output based on the signal 3a relating to (S). The target steering torque setting means 14 is composed of, for example, a ROM or the like, and is composed of a conversion table that stores a target steering torque value Th preset corresponding to each steering torque TS. The target steering torque setting means 14 may be configured to calculate and output the target steering torque value Th on the basis of a functional expression registered in advance.

The driving means 15 is the motor current value setting means 1
6, subtraction means 17, and four power semiconductor elements 18a
-18d motor current supply circuit 1 with two-phase bridge connection
8 and a motor current detector 19 for detecting the current value actually supplied to the motor 11 including its polarity.

The motor current value setting means 16 has a correspondence table between the auxiliary steering torque value Th and the motor drive current IT, and outputs a motor current command 16a according to the signal 14a relating to the auxiliary steering torque value Th. The subtracting means 17 uses the motor current command 16a and the detection signal 1 of the motor current detector 19.
The deviation from 9a is calculated, and a signal relating to the deviation ΔI of the motor current is output as 17a. The motor current supply circuit 18 drives and controls each of the power semiconductor elements 18a to 18d according to a preset rule based on the deviation ΔI of the motor current, thereby controlling the polarity of the current supplied to the motor 11 and the current value. Is configured as follows.

The hydraulic power steering system A according to the first aspect of the present invention is configured as described above, and the steering torque detecting means 3 is provided.
The target steering torque setting means 14 in the control means 13 sets the steering assist torque (Th) on the basis of the signal 3a relating to the steering torque (TS) detected in. And the driving means 15
Drives the oil passage switching means 10 by operating the motor 11 based on the signal relating to the set steering assist torque (Th). As a result, the hydraulic pressure supplied to the right chamber 9c and the left chamber 9d of the power cylinder unit 9 is controlled, and the auxiliary steering torque (Th) set by the target steering torque setting unit 14 can be given.

FIG. 6 is a block diagram of the hydraulic power steering apparatus according to the third aspect. In the hydraulic power steering device B according to claim 3, a signal 3 a relating to the steering torque (TS) detected by the steering torque detecting means 3 and a signal 2 relating to the steering angle (θ) detected by the steering angle detecting means 20.
The control unit 21 supplies a drive command 21a to the motor 11 based on 0a.

FIG. 7 is a block diagram of the control means of the hydraulic power steering apparatus according to the third aspect. The control means 21 includes a target steering torque setting means 22, a deviation calculation means 23, and a drive means 15.

The target steering torque setting means 22 generates and outputs a signal 22a relating to the steering torque value (Tθ) based on the signal 20a relating to the steering angle (θ) detected by the steering angle detecting means 20. The target steering torque setting means 22 is, for example, a ROM or the like, and is configured by a conversion table that stores a target steering torque value (Tθ) preset corresponding to the steering angle (θ). Note that the target steering torque value (Tθ) may be calculated and output based on a previously registered functional expression or the like.

Here, the target steering torque setting means 22 is
As shown in the graph in FIG. 7, when the steering angle (θ) is in a relatively small range around the neutral position, the target torque value (Tθ) obtained by multiplying the steering angle (θ) by a relatively large coefficient.
Is set, and the target steering torque value (Tθ) is gradually increased when the steering angle (θ) exceeds a predetermined threshold value and becomes large.

The steering angle (θ) is proportional to the turning angle of the wheel.
In garage parking or the like, the steering wheel 1 is normally operated 3 to 4 rotations (1080 to 1440 degrees) from one lock position to the other lock position. During traveling, for example, at a speed of about 80 km / h, the steering angle (θ) is at most about 60 degrees. Therefore, when the steering angle (θ) is relatively small, the steering torque proportional to the steering angle is given,
The slope of the graph is changed so that the characteristics of power steering can be fully obtained when entering a garage.

The deviation calculating means 23 is a deviation ΔT (ΔT) between the signal 22a relating to the target steering torque Tθ output from the target steering torque setting means 22 and the signal 3a relating to the steering torque TS detected by the steering torque detecting means 3. = Tθ-TS)
And outputs a signal 23a relating to the deviation ΔT.

Next, the operation of the hydraulic power steering device according to the third aspect will be described. A target steering torque value Tθ preset corresponding to the steering angle θ of the steering wheel 1 detected by the steering angle detection means 20 is output from the target steering torque setting means 22. The deviation ΔT between the target steering torque value Tθ and the steering torque TS detected by the steering torque detecting means 3 is calculated by the deviation calculating means 23, and a drive command 21a (specifically, a preset drive command 21a corresponding to the deviation ΔT is obtained. (Motor current) is supplied to the motor 11, and the power cylinder means 9 supplies an auxiliary steering force corresponding to the deviation ΔT.

The oil passage switching means 10 determines, based on the polarity and value of the current supplied to the motor 11 which is an actuator.
Since the moving direction and the moving amount of the spool 10a shown in FIG. 4 are determined, the power cylinder means 9 shown in FIG.
The direction and magnitude of the auxiliary steering force supplied from the vehicle through the rack shaft 5 are controlled.

Since the hydraulic power steering apparatus B according to the third aspect is configured to determine the steering torque Tθ based on the steering angle θ, it is possible to obtain a good steering feeling of the steering handle 1 returning.

FIG. 8 is a block diagram of the control means of the hydraulic power steering apparatus according to the fourth aspect. This control means 40 is a signal 41 relating to the lateral acceleration G detected by the lateral acceleration detecting means 41 for detecting the lateral acceleration of the vehicle.
Target steering torque value (TG) set in advance based on a
Target steering torque setting means 4 for outputting a signal 42a relating to
2, deviation calculation means 43, and drive means 15.
The target steering torque setting means 42 is, for example, a ROM or the like, and is configured by a conversion table that stores a target torque value (TG) preset corresponding to the lateral acceleration G.

The deviation calculating means 43 is a deviation between the signal 42a relating to the target steering torque value (TG) output from the target steering torque setting means 42 and the signal 3a relating to the steering torque TS detected by the steering torque detecting means 3. ΔT (ΔT = TG-
TS) is calculated and the signal 43a relating to the deviation ΔT is output. The driving means 15 is the same as that described above.

As described above, since the hydraulic power steering apparatus according to the fourth aspect is configured to give the auxiliary steering force based on the lateral acceleration G of the vehicle and the steering torque (TS), the reaction force against the lateral acceleration is applied. Can be given.

FIG. 9 is a block diagram of the control means of the hydraulic power steering apparatus according to the fifth aspect. This control means 50 is a signal 5 relating to the yaw rate (Φ) detected by the yaw rate detection means 51 for detecting the yaw rate of the vehicle.
1a based on a preset target steering torque value (T
Φ) target steering torque setting means 52 for outputting a signal relating to
And the deviation calculating means 53 and the driving means 15. The target steering torque setting means 52 uses, for example, a ROM,
The conversion table stores a target torque value (TΦ) preset corresponding to the yaw rate (Φ).

The deviation calculating means 53 is a deviation between the signal 52a relating to the target steering torque value (TΦ) output from the target steering torque setting means 52 and the signal 3a relating to the steering torque TS detected by the steering torque detecting means 3. ΔT (ΔT = TΦ−
TS) is calculated and a signal 53a relating to the deviation ΔT is output. The driving means 15 is the same as that described above.

As described above, the hydraulic power steering apparatus according to the fifth aspect of the invention has a yaw rate Φ and a steering torque T of the vehicle.
Since the auxiliary steering force is applied based on S, the reaction force to the yaw rate can be applied.

FIG. 10 is a block diagram showing another embodiment of the control means according to claims 4 and 5. The control device 60 includes a target steering torque value (TG) corresponding to the lateral acceleration (G) output from the first target steering torque setting means 61 and a yaw rate output from the second target steering torque setting means 62. The target steering torque value (TΦ) corresponding to (Φ) is added by the addition means 63, and the addition output 63
The deviation between the steering torque (TS) and the steering torque (TS) is obtained by the deviation calculating means 64, and the driving means 15 drives the motor 11 based on the deviation.
The oil passage switching means 10 is driven via the.

[0042]

As described above, the hydraulic power steering apparatus according to the first aspect of the present invention is configured to drive the oil passage switching means via the motor based on at least the steering torque detected by the steering torque detecting means. The direction and magnitude of the auxiliary steering force supplied from the power cylinder means can be freely set.

Since the hydraulic power steering apparatus according to the second aspect comprises the target steering torque setting means for setting the target steering torque based on the steering torque, the characteristics of the target steering torque setting means can be set appropriately. The direction and magnitude of the auxiliary steering force can be freely set.

In the hydraulic power steering apparatus according to the third aspect, the target steering torque corresponding to the steering angle is set based on the detection signal from the steering angle detecting means, and the steering detected by the target torque and the steering torque detecting means. Since the configuration is such that the deviation from the torque is obtained and the oil passage switching means is controlled based on the deviation, it is possible to supply the steering torque according to the steering.

Since the hydraulic power steering system according to the fourth and fifth aspects is configured to set the target steering torque based on the lateral acceleration or yaw rate of the vehicle, the steering reaction force is applied according to the dynamic characteristics of the vehicle. You can Therefore, it is possible to improve the low friction coefficient and the self-restoring property against disturbance.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a hydraulic power steering device according to claims 1 and 2.

FIG. 2 is a structural diagram showing a specific example of steering torque detecting means.

FIG. 3 is an explanatory diagram showing the operation and detection output characteristics of the steering torque detecting means shown in FIG.

FIG. 4 is a structural diagram showing a specific example of oil passage switching means.

FIG. 5 is a block configuration diagram of control means of the hydraulic power steering device according to claims 1 and 2.

FIG. 6 is a block configuration diagram of a hydraulic power steering device according to claim 3;

FIG. 7 is a block configuration diagram of control means of the hydraulic power steering device according to claim 3;

FIG. 8 is a block configuration diagram of control means of the hydraulic power steering device according to claim 4;

FIG. 9 is a block configuration diagram of control means of the hydraulic power steering device according to claim 5;

FIG. 10 is a block diagram showing another embodiment of the control means of the hydraulic power steering system according to claims 4 and 5.

[Explanation of symbols]

1 Steering Handle 3 Steering Torque Detecting Means 8 Wheels 9 Power Cylinder Means 10 Oil Path Switching Means 11 Motor 12 Hydraulic Pump Means 13, 21, 40, 50, 60 Control Means 14, 22, 41, 52, 61, 62 Target Steering Torque Setting means 15 Driving means 20 Steering angle detecting means 23, 43, 53, 64 Deviation calculating means 41 Lateral acceleration detecting means 51 Yaw rate detecting means A, B Hydraulic power steering device Th Target steering torque value based on steering torque TG For lateral acceleration Target steering torque value based on TS Steering torque Tθ Target steering torque value based on steering angle TΦ Target torque value based on yaw rate

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B62D 137: 00

Claims (5)

[Claims] 1. A steering torque detecting means for detecting a steering torque input to a steering wheel, a power cylinder means for urging an assisting force for turning a wheel, and a hydraulic pressure as a hydraulic source of the power cylinder means. Pump means, oil passage switching means for switching the biasing direction and biasing force of the power cylinder means, a motor for operating this oil passage switching means, and the motor based on at least the steering torque detected by the steering torque detecting means. A hydraulic power steering device comprising: 2. A steering torque detecting means for detecting a steering torque input to a steering wheel, a power cylinder means for urging an assisting force for turning a wheel, and a hydraulic pressure as a hydraulic source of the power cylinder means. Pump means, oil passage switching means for switching the biasing direction and biasing force of the power cylinder means, a motor for operating this oil passage switching means, and a target steering torque based on the steering torque detected by the steering torque detecting means. And a control means for controlling the motor according to the set target steering torque. 3. A steering torque detecting means for detecting a steering torque input to a steering wheel, a steering angle detecting means for detecting a steering angle of the steering wheel, and an assisting force for turning a wheel. Power cylinder means,
From the hydraulic pump means serving as the hydraulic pressure source of the power cylinder means, the oil passage switching means for switching the urging direction and the urging force of the power cylinder means, the motor for operating the oil passage switching means, and the steering angle detecting means. And a target steering torque setting means for setting a target steering torque based on the detection signal of the steering torque, and based on a deviation between the target steering torque set by the target torque setting means and the steering torque detected by the steering torque detecting means. A hydraulic power steering device comprising: a control unit that controls a motor. 4. A steering torque detecting means for detecting a steering torque input to a steering wheel, a lateral acceleration detecting means for detecting a lateral acceleration of a vehicle, and a power cylinder for applying an assisting force to the turning of a wheel. Means, hydraulic pump means serving as a hydraulic pressure source of the power cylinder means, oil passage switching means for switching the urging direction and urging force of the power cylinder means, a motor for operating the oil passage switching means, and the lateral acceleration. A target steering torque setting means for setting a target steering torque based on a detection signal from the detection means is provided, and the deviation between the target steering torque set by the target torque setting means and the steering torque detected by the steering torque detection means is set. A hydraulic power steering device comprising: a control unit that controls the motor based on the above. 5. A steering torque detecting means for detecting a steering torque input to a steering wheel, a yaw rate detecting means for detecting a yaw rate of a vehicle, and a power cylinder means for urging an assisting force for turning a wheel. A hydraulic pump means which is a hydraulic pressure source of the power cylinder means, an oil passage switching means for switching the urging direction and the urging force of the power cylinder means, a motor for operating the oil passage switching means, and the yaw rate detecting means. And a target steering torque setting means for setting a target steering torque based on the detection signal of the steering torque, and based on a deviation between the target steering torque set by the target torque setting means and the steering torque detected by the steering torque detecting means. A hydraulic power steering device comprising: a control unit that controls a motor.