JP3345804B2 - Vehicle steering system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering system for steering a vehicle according to a driver's operation.

[0002]

2. Description of the Related Art Steering of a vehicle is performed by operating a steering means disposed inside the vehicle compartment, for example, by rotating a steering wheel, by steering a steering wheel (generally, a front wheel). Is transmitted to a steering mechanism arranged outside the vehicle. In recent years, an actuator for assisting steering such as a hydraulic cylinder and an electric motor is arranged in the middle of the steering mechanism, and the actuator is driven based on a detection result of an operating force applied to a steering wheel for steering. , Assists the operation of the steering mechanism according to the rotation of the steering wheel,
2. Description of the Related Art A power steering device (power steering device) configured to reduce a labor burden on a driver for steering is widely used.

However, in such a conventional steering apparatus for a vehicle, a mechanical connection between a steering wheel, which is a steering means, and a steering mechanism is required, and the position of the steering wheel in the vehicle interior is limited. However, there is a problem that the steering wheel is limited to a position where it can be connected to the steering mechanism outside the vehicle compartment. Further, even when the steering wheel is provided so as to be connectable, a complicated structure is required to realize the connection. The connection structure is required, which is a factor that hinders weight reduction of the vehicle and simplification of the assembly process.

[0004] For example, Japanese Utility Model Publication No. 2-29017 discloses a steering device for a vehicle which is a linkless power steering device for solving such a problem. This steering apparatus for a vehicle has a steering wheel mechanically separated from a steering mechanism, and is provided with an actuator for steering in the middle of the steering mechanism, similarly to an actuator for assisting steering in a conventional power steering apparatus. An electric motor is arranged, and this electric motor is
By driving based on the detection result of the operation direction and the operation amount of the steering wheel, the steering according to the operation of the steering wheel is performed.

[0005] The vehicle steering apparatus of the separated type configured as described above increases the degree of freedom in arranging the steering wheel.
In addition to the above-mentioned objectives such as reducing the weight of the vehicle, realization of new steering means such as levers and pedals instead of the steering wheel, detection of guidance signs on the road surface, reception of satellite information, etc. It is useful for the future development of automobile technology such as realization.

[0006]

In a conventional power steering device (power steering device), the power key is turned off in conjunction with the ignition key during traveling, and even if the steering assist force is lost, the steering wheel and the steering wheel are steered. Steering is possible because the mechanism is mechanically connected. However, in a separated type vehicle steering system in which the steering wheel and the steering mechanism are not mechanically connected, when the power key is turned off and the power is cut off, the steering mechanism is operated even if the steering wheel is operated. Does not work, and of course the tires do not move. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a separated type vehicle steering device that can continue steering even when a power key is accidentally turned off.

[0007]

A vehicle steering apparatus according to the present invention is not mechanically connected to a steering mechanism for changing the direction of wheels, detects a steering angle of the steering means, and responds to the detected steering angle. A vehicle steering device that controls the steering angle of the steering mechanism to increase or decrease, wherein a detecting means for detecting that a power switch for turning on / off a power supply is turned on / off; Power-supply operation means for turning on / off the power supply in accordance with an on / off operation of a power switch; and judgment means for judging whether or not the input traveling speed of the vehicle is lower than a predetermined speed; When detecting the off operation of the power switch, only when the determination unit determines that the traveling speed is lower than a predetermined speed, the power operation unit is configured to turn off the power. I do.

In this vehicle steering system, the detecting means detects that the power switch for turning on / off the power is turned on / off. The power supply operation unit turns on / off the power supply in accordance with the on / off operation of the power switch detected by the detection unit, and the determination unit determines whether the input traveling speed of the vehicle is lower than a predetermined speed. . When the detecting means detects the turning off operation of the power switch, the power operating means turns off the power only when the determining means determines that the traveling speed of the vehicle is lower than the predetermined speed. Thus, even if the power key is accidentally turned off while the vehicle is running, steering can be continued.

[0009]

[0010]

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing an embodiment. Embodiment 1 FIG. FIG. 1 is a block diagram showing a configuration of a vehicle steering system according to a first embodiment of the present invention. This vehicle steering system
A steering mechanism 1 for causing a pair of steering wheels 10, 10 disposed on the left and right sides of a vehicle body (not shown) to perform a steering operation.
A steering wheel 2 as steering means mechanically separated from the steering mechanism 1, a reaction force actuator 3 for applying a reaction force to the steering wheel 2, and a steering control unit 4 using a microprocessor. The operation of the steering control unit 4 in accordance with the operation of the steering wheel 2 drives the steering motor 5 arranged in the middle of the steering mechanism 1 to operate the steering mechanism 1.

As is well known, the steering mechanism 1 includes both ends of a steering shaft 11 that extends in the left-right direction of the vehicle body and slides in the axial direction, and knuckle arms 12 that support the wheels 10, 10.
12 are connected by separate tie rods 13, 13, respectively.
The tie rods 13 and 1 are moved by sliding the steering shaft 11 in both directions.
The knuckle arms 12, 12 are pushed and pulled via 3 to steer the wheels 10, 10 to the left and right. This steering is performed by the steering motor 5, which is coaxially formed in the middle of the steering shaft 11. The rotation is converted into sliding of the steering shaft 11 by an appropriate motion conversion mechanism.

The rotation of the steering shaft 11 around the axis thereof is restricted by rotation restricting means (not shown) interposed between the steering shaft 11 and the steering shaft housing 14. And the steering (steering of the steering wheels 10, 10) according to the rotation of the steering motor 5 is performed. The steering angles of the wheels 10, 10 steered in this way are determined by a relative sliding position between the steering shaft housing 14 on one side of the steering motor 5 and the steering shaft 11 as a medium.
The output of the steering angle sensor 16 is provided to the steering control unit 4 together with the output of the rotary encoder 15 for detecting the rotational position of the steering motor 5.

The reaction force actuator 3 for applying a reaction force to the steering wheel 2 is an electric motor (for example, a three-phase brushless motor), and its casing is fixed to an appropriate portion of a vehicle body (not shown) in relation to the rotating shaft 30. It is attached. The steering wheel 2 is coaxially fixed to a protruding end on one side of the rotating shaft 30, and a protruding end on the other side is
A torsion spring 31 having a predetermined elasticity is connected to an appropriate portion of a vehicle body (not shown).

The reaction force actuator 3 has a drive circuit 3a corresponding to a reaction force instruction torque signal given from the steering control unit 4.
When the steering wheel 2 is mounted on one end of the rotating shaft 30, a force (reaction force) in a direction opposite to the operation direction is applied to the steering wheel 2 attached to one end of the rotating shaft 30. Therefore, it is necessary to apply a steering torque against the reaction force generated by the reaction force actuator 3 to the rotation operation of the steering wheel 2.
Is detected by a torque sensor 32 attached to the reaction force actuator 3.

The operation amount (steering angle) of the steering wheel 2 is detected including the operation direction by a rotary encoder 33 attached to the reaction force actuator 3. Has been given to. Also, the driving circuit 3a supplies the reaction force actuator 3
Is supplied to the steering control section 4 by the current sensor 3b.

The torsion spring 31 interposed between the other end of the rotating shaft 30 and a part of the vehicle body causes the rotating shaft 30 to rotate due to its elasticity when the rotating operation performed as described above is stopped. Thus, the steering wheel 2 returns to a predetermined neutral position. This return is necessary for returning the steering wheel 2 in accordance with the return operation of the wheels 10, 10 in the straight traveling direction, which occurs on the steering mechanism 1 side that is not mechanically connected.

The steering control unit 4 is connected to a positive electrode of a battery B, whose negative electrode is grounded, which is a power supply for supplying electric power, directly and via a switch S2. This is a part that requires power even while the switch S2 is off. Power is supplied via the switch S2 to the reaction force actuator 3, the steering motor 5
And the drive circuits 3a and 5a. Also, the steering control unit 4
Is connected to a vehicle speed sensor 6 for detecting the running speed of the vehicle, and a power switch S1 for turning on / off the battery B, the other being grounded.

The output of the steering control unit 4 is given to the reaction force actuator 3 and the steering motor 5 via separate drive circuits 3a, 5a. The reaction force actuator 3 and the steering motor 5 Each operation is performed in response to an instruction signal from the unit 4.

The steering control unit 4 includes the steering wheel 2
Is determined, and a reaction force control for generating a reaction force instruction torque signal to the reaction force actuator 3 to generate a reaction force is performed. Further, the steering control unit 4 recognizes an operation angle including an operation direction of the steering wheel 2 based on an input from the rotary encoder 33, and recognizes an operation angle based on an input from the steering angle sensor 16 attached to the steering mechanism 1. A steering angle deviation from the steering angle is obtained, and this steering angle deviation is corrected so as to be larger or smaller in accordance with the vehicle speed given as an input from the vehicle speed sensor 6, and a target steering angle is obtained. The steering control operation for driving the steering motor 5 is performed until the operation is performed. At this time, an input from the rotary encoder 15 is used as a feedback signal for checking whether or not the steering motor 5 has reached a desired rotational position.

The operation related to the power switch S1 of the vehicle steering system having the above-described structure according to the present invention will be described below with reference to the flowchart of FIG. When the power switch S1 (switch) is turned on (S2), the steering controller 4 turns on the switch S2 to turn on the power (S3). The steering control unit 4 performs the steering control in this state (S4). During the steering control (S4), when the power switch S1 (switch) is turned off (S6), the steering controller 4 reads the vehicle speed from the vehicle speed sensor 6 (S6).
8) In order to determine whether the vehicle is in a stopped state, it is determined whether the read vehicle speed is lower than a predetermined speed (S).
10).

When the read vehicle speed is not lower than the predetermined speed (S10), the steering control unit 4 determines that the vehicle is in a running state and performs steering control as it is (S4). When the read vehicle speed is lower than the predetermined speed (S10), the steering control unit 4 determines that the vehicle is in a stopped state, waits for a predetermined time (S12), turns off the switch S2, and turns off the power. (S14).

Embodiment 2 FIG. FIG. 3 is a block diagram showing a configuration of a second embodiment of the vehicle steering system according to the present invention. This vehicle steering system
A positive electrode of a battery B whose negative electrode is grounded, which is a power supply for supplying electric power, is directly connected to the steering control unit 4. Further, the positive electrode of the battery B is connected to the steering control unit 4 via a power switch S3 for turning on / off the battery B. The portion directly connected to the positive electrode of the battery B is a portion that requires power even while the switch S3 is off. Power is supplied via the power switch S3 to the reaction force actuator 3, the steering motor 5, the drive circuits 3a, 5a, and the like.

A large-capacity capacitor C is connected to the steering control unit 4 in parallel with a series circuit including a power switch S3 and a battery B, and a discharge resistor R is connected to the capacitor C in parallel. Other configurations are the same as the configuration of the vehicle steering system according to the first embodiment described above (however,
The power switch S1 and the switch S2 do not exist), and the description is omitted.

In the vehicle steering system having such a configuration, the capacitor C is charged while the power switch S3 is turned on. When the power switch S3 is turned off, the electric power charged in the capacitor C is discharged and supplied to the steering control unit 4. The steering apparatus for a vehicle can continue steering while the discharge voltage of the capacitor C is within the operable voltage range of the steering control unit 4, the reaction force actuator 3, the steering motor 5, the drive circuits 3a, 5a, and the like.

[0026]

According to the vehicle steering system of the present invention,
Even if the power key is accidentally turned off while the vehicle is running,
Steering is still possible.

[0027]

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of a vehicle steering system according to the present invention.

FIG. 2 is a flowchart showing an operation of the vehicle steering system shown in FIG.

FIG. 3 is a block diagram showing a configuration of a second embodiment of the vehicle steering system according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steering mechanism 2 Steering wheel (steering means) 3a, 5a Drive circuit 4 Steering control part (judgment means, power supply operation means, detection means) 5 Steering motor 6 Vehicle speed sensor B Battery (power supply) C Capacitor R Resistance S1 Power switch S2 Switch (power operation means) S3 Power switch

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Nobuyoshi Sugitani 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (56) References JP-A-08-12992 (JP, A) JP-A-8- 188164 (JP, A) JP-A-10-278826 (JP, A) JP-A-63-18381 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B62D 6/00 B62D 5 / 04

Claims (1)

(57) [Claims] 1. A vehicle which is not mechanically connected to a steering mechanism for changing the direction of wheels, detects a steering angle of a steering means, and controls a steering angle of the steering mechanism according to the detected steering angle. Detecting means for detecting that a power switch for turning on / off a power supply is turned on / off, and turning on the power supply in accordance with an on / off operation of the power switch detected by the detection means. Power supply operation means for turning on / off, and determination means for determining whether or not the input traveling speed of the vehicle is lower than a predetermined speed, wherein when the detection means detects an off operation of the power switch, The vehicular steering apparatus according to claim 1, wherein the power supply operating means turns off the power supply only when the determination means determines that the traveling speed is lower than a predetermined speed.