JPH01178079A - Power steering controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a power steering control device, and in particular, when the power supply to a control unit that controls the drive of an electric motor is cut off while the slave steering wheels are being steered, A power steering control device that can improve safety by short-circuiting both terminals of the electric motor and operating the electric motor like a generator to gradually converge the slave steering wheels to zero, preventing sudden changes in vehicle behavior. Regarding.

[Conventional technology]

In a vehicle, normally, a front wheel, which is a main steering wheel, is provided so as to be steerable in a desired direction of travel of the vehicle, and a rear wheel, which is a secondary steering wheel, is provided parallel to the longitudinal direction of the vehicle.

When a vehicle that steers two front wheels is turned by steering the front wheels, the front wheels and rear wheels do not match the turning circle, and at low vehicle speeds, the rear wheels end up inside the turning circle due to the difference between the inner wheels. The vehicle turns in this position, and at high vehicle speeds, the centrifugal force causes the vehicle to turn in such a position that the front wheels are inside the turning circle. For this reason, there is a problem in that even if the front wheels are steered in the turning direction, which is the traveling direction of the vehicle, the attitude of the vehicle cannot be made to match the turning direction.

Therefore, a vehicle has been proposed that has a four-wheel steering control device that improves running performance by steering not only the front wheels but also the rear wheels. That is, in this steering control device,
The main steering means is a steering device that steers the front wheels, and the secondary steering means is a rear wheel steering device that steers the rear wheels. While improving turning performance, it is also possible to improve steering stability during lane changes, etc. at medium and high speeds.

In addition, as shown in Figure 4, the steering control device is designed to reduce the size and weight of the slave steering means that steers the rear wheels, increasing the degree of freedom in installation, and eliminating the need for oil leakage countermeasures. Various steering control devices have been considered that steer the rear wheels using an electric motor, that is, the electric motor 44 as a power source. This steering control device is operated by power from the power supply section 64 of battery B and ignition IG, and is operated by the front wheel steering state from the front wheel steering angle sensor 58, the rear wheel steering state from the rear wheel steering angle sensor 60, and the vehicle speed sensor. There is a control section 66 that detects the vehicle speed state from 62 and controls the drive of the electric motor 44.

Further, a steering control device using an electric motor is disclosed in, for example, Japanese Patent Laid-Open No. 146683/1983.

This publication describes an electric rear axle steering mechanism that operates an output member connected to the rear tie rod of the rear wheels in synchronization with the rotation of an electric motor to control the amount of steering of the rear wheels;
It is equipped with a neutral holding reaction force mechanism that applies a reaction force corresponding to the output of this electric rear axle steering mechanism to the rear tie rod of the rear wheels to regulate the amount of rear wheel turning, thereby improving the tracking delay of the rear wheels. ,
This improves the running stability and steering stability of the vehicle.

[Problem that the invention seeks to solve]

However, in conventional steering control devices, when the power supply to the control unit is cut off while the vehicle is running and the rear wheels are being steered, the power supply from the control unit to the electric motor is also cut off. As a result, this electric motor immediately stops, and the rear wheels are suddenly returned to near the neutral position due to the biasing force of the return spring of the neutral position holding mechanism, resulting in changes in vehicle behavior that the driver cannot respond to. This happened rapidly and was extremely dangerous.

[Purpose of the invention]

Therefore, the purpose of this invention is to eliminate the above-mentioned disadvantages.
If the power supply to the control unit is cut off while the slave steering wheel is being steered, the amount of electricity generated by the inertial rotation until the motor stops is used to drive the electric motor to prevent the motor from stopping suddenly and perform slave steering. By shorting both terminals of the electric motor in order to help the steering angle of the wheels converge to zero, sudden changes in vehicle behavior are prevented and safety is improved.
An object of the present invention is to realize a power steering control device that can reduce the shock given to a passenger.

[Means for solving problems]

To achieve this object, the present invention provides a main steering means for steering a main steering wheel, a slave steering means for steering a slave steering wheel, and an electric motor that operates the slave steering means to steer the slave steering wheel. A power steering control device comprising: a control unit that detects at least a steering state of the main steering wheel and a steering state of the slave steering wheel and controls the driving of the electric motor; A neutral position holding mechanism is provided to maintain the steering angle of the wheels at zero, and when the power supply to the control unit is cut off while the slave steering wheel is being steered, the rotation angle generated by the inertial rotation until the electric motor is stopped is provided. A short-circuit circuit is provided to short-circuit both terminals of the electric motor in order to drive the electric motor with the amount of electricity to prevent the electric motor from stopping abruptly and to gradually converge the turning angle of the slave steering wheel to zero. It is characterized by

[Operation] According to the configuration of the present invention, when the power supply to the control unit is cut off while the slave steering wheel is being steered, the short circuit shorts both terminals of the electric motor, and the inertia of the electric motor is reduced until the electric motor stops. The amount of electricity generated by the rotation drives the electric motor, prevents the electric motor from stopping abruptly, and gently converges the turning angle of the subordinate steered wheels to zero.

As a result, it is possible to prevent sudden changes in the behavior of the vehicle, thereby improving safety conditions, and reducing the shock given to the occupants.

〔Example〕

Embodiments of the present invention will be described in detail and specifically below based on the drawings.

1 to 3 show embodiments of this invention. In the figure, 2 is a vehicle, 4 is a steering wheel, 6 is a steering shaft, 8 is a main steering means which is a steering device, 10 and 10 are front wheels which are main steering wheels, and 12 is a slave steering device which is a rear wheel steering device. The steering means 14, 14 are rear wheels that are slave steering wheels, and 16 is a speed reduction mechanism.

The main steering direction means 8 includes a front pinion 18 fixed to the tip end of the steering shaft 6 and a front rack 2 provided on a front rack bar 20 to mesh with the front pinion 18.
A front rack and pinion mechanism 24 consisting of 2 and a front tie rod 26 and 2 connected to each end of the front rack bar 20.
6 and front knuckle arms 28, 28 connected to the front tie rods 26, 26 and connected to the front wheels 10, 10.
Consisted of.

The slave steering means 12 is connected to a connecting shaft 30 from the deceleration mechanism 16.
a rear pinion 32 provided on the rear rack bar 34 and a rear rack 3 provided on the rear rack bar 34 to mesh with the rear pinion 32;
6, a rear rack pinion mechanism 38, and a rear tie rod 40 connected to each end of the rear rack bar 34.
40 and rear knuckle arms 42, 4 connected to the rear tie rods 40, 40 and connected to the rear wheels 14, 14.
Consisting of 2. That is, the drive of the speed reduction mechanism 16 rotates the rear pinion 32 via the communication shaft 30, and the rotation of the rear pinion 32 causes the rear rack bar 34 to move toward the vehicle 2.
It moves from side to side.

The speed reduction mechanism 16 is connected via a transmission shaft 46 to an electric motor 44 that drives and controls the slave steering means 12 . When power is not supplied to the electric motor 44 and the deceleration mechanism 16 is not controlled, and the rear rack bar 34 freely moves in the left-right direction of the vehicle 2 and the rear wheels 14 are in a free state, the rear A neutral position holding mechanism 48 consisting of a spring or the like in which the side rack bar 34 is preset holds the rear wheels 14 in the neutral position.
The steering angle of No. 14 is maintained at zero.

As shown in FIG. 3, this neutral position holding mechanism 48 includes first and second springs whose one ends 52a and 54a are respectively symmetrically engaged with a locking portion 50 protruding from the rear rack bar 34. 52 and 54, these first and second springs 52
．． The other ends 52b, 54b of 54 are the left and right vehicle bodies 56a, 5.
6b, respectively.

The electric motor 44 is connected to a front wheel steering angle sensor 58 that detects the rotation amount of the steering shaft 6 as the steering amount and steering force of the front wheels 10, 10, and a front wheel steering angle sensor 58 that detects the rotation amount of the steering shaft 6 as the steering amount and steering force of the front wheels 10. A rear wheel steering angle sensor 60 that detects an angle quantity, a vehicle speed sensor 62 that detects the speed of the vehicle 2, and a power source section 64 of the battery power source B and ignition IC communicate with each other and are driven and controlled by a control section 66. That is, this control section 66 controls the steering state of the front wheels 10, 10 and the rear wheels 14.
14's steering status and vehicle speed, etc., and the rear wheels 14.1
The electric motor 44 is driven and controlled to steer the rear wheels 14 and 1, and the reduction mechanism 16 and the slave steering means 12 are operated to steer the rear wheels 14 and 1.
4 to control the steering.

Further, between the electric motor 44 and the control unit 66, the rear wheel 14
- If the power supply from the power supply section 64 of the battery B/ignition IG to the control section 66 is cut off during the steering of the electric motor 44, the amount of electricity generated by the inertial rotation until the electric motor 44 stops is used to power the electric motor 44. A short-circuit circuit that short-circuits both terminals 44a and 44b of the electric motor 44 in order to prevent the electric motor 44 from stopping suddenly and to gradually converge the steering angle of the rear wheels 14 to zero. A relay 68 is provided.

This motor short circuit relay 68 includes a relay coil 70,
When current flows through the relay coil 70, the relay contact 72 connects to the relay terminal 74a to allow power supply to the electric motor 44, while current flows through the relay coil 70. If not, relay contact 72
is connected to the relay terminal 74b to cut off the power supply to the electric motor 44, and both terminals 44a, 44 of the electric motor 44 are connected to the relay terminal 74b.
This is a configuration in which the terminals b are short-circuited. As a result, the rear wheel 14
- When the steering angle of the rear wheels 14 is about to be returned to zero by the action of the neutral position holding mechanism 48 during the steering of the rear wheels 14, the electric motor 44 is operated like a generator, and the rear wheels 14
・This is to gradually converge the steering angle of No. 14 to zero.

Next, the operation of this embodiment will be explained.

While vehicle 2 is running, battery B and ignition I
The control means 52, which is supplied with power from the power supply section 64 of the vehicle G, receives a front wheel turning angle signal and a front wheel turning force signal from the front axle steering angle sensor 58, and a rear wheel turning signal from the rear wheel steering angle sensor 60. An angle signal and a vehicle speed signal from a vehicle speed sensor 62 are input. Further, in the motor short circuit relay 68, current flows through the relay coil 70 and the relay contact 72 connects to the relay terminal 74.
a, supplies power to the electric motor 44, and drives the electric motor 44. Therefore, the control unit 66 drives and controls the electric motor 44 in order to control the steering of the rear wheels 14, 14 according to the steering state of the front wheels 10, 10. The operation of the electric motor 44 operates the deceleration mechanism 16 and the slave steering means 12 to control the steering of the rear wheels 14 in a predetermined manner.

In this way, when controlling the steering of the rear wheels 14, 14, the power supply unit 64 of the battery B/ignition IG
When the power supply to 6 is cut off, no current flows through the relay coil 70 of the motor short circuit 68, and the relay contact 72 is separated from the relay terminal 74a and connected to the relay terminal 74b.

Therefore, the power supply from the control unit 66 to the electric motor 44 is cut off, and the slave steering means 12 becomes in a state where it can freely operate with respect to the electric motor 44. And neutral position holding mechanism 48
Due to the biasing action of the first and second springs 52 and 54,
The steering angle of the rear wheels 14 is returned to zero.

However, at this time, the electric motor 44 is connected to the relay contact 72
is connected to the relay terminal 74b and both terminals 44a and 44b are short-circuited, and the electricity generated by the inertial rotation until the stop is activated like a generator, and the first and second terminals of the neutral position holding mechanism 48 are 2 resists the biasing action of the springs 52 and 54, prevents the rear wheels 14, 14 from rapidly returning to the straight running state, and causes the turning angle of the rear wheels 14, 14 to gradually converge to zero over time. .

Thereby, the rear wheels 14, 14 can be returned to the neutral position without causing a sudden change in the behavior of the vehicle 2, and safety can be improved. Moreover, the shock given to the occupants can be significantly reduced and discomfort caused to the occupants can be prevented.

〔Effect of the invention〕

As is clear from the above detailed description, according to the present invention,
If the power supply to the control unit is cut off while the slave steering wheel is being steered, the amount of electricity generated by the inertial rotation until the motor stops is used to drive the electric motor to prevent the motor from stopping suddenly and perform slave steering. By providing a short circuit that shorts both terminals of the electric motor in order to gradually converge the steering angle of the wheels to zero, if the power supply to the control unit is cut off while the slave steered wheels are being steered, the short circuit will not occur. The circuit shorts both terminals of the motor, and the amount of electricity generated by the inertial rotation until the motor stops drives the motor, preventing the motor from stopping suddenly and gradually reducing the turning angle of the slave steering wheels to zero. By converging, it is possible to prevent sudden changes in the behavior of the vehicle and improve safety, and it is also possible to reduce the shock given to the occupants and prevent them from feeling uncomfortable.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention, in which FIG. 1 is a schematic diagram of a vehicle, FIG. 2 is a circuit diagram of a steering control device, and FIG. 3 is a schematic plan view of a neutral position holding mechanism. FIG. 4 is a circuit diagram of a conventional steering control device. In the figure, 2 is the vehicle, 4 is the steering wheel, and 8 is the vehicle.
10 is a main steering means, 10 is a front wheel, 12 is a slave steering means, 14 is a rear wheel, 44 is an electric motor, 48 is a neutral position holding mechanism, 52 is a first spring, and 54 is a second spring , 58 is a front axle steering angle sensor, 60 is a rear wheel steering angle sensor, 62 is a vehicle speed sensor, 64 is a power supply unit for battery B/ignition IC, 68 is a motor short circuit relay, 70
is a relay coil, and 72 is a relay contact. Patent Applicant Suzuki Motor Co., Ltd. Agent Patent Attorney Yoshimi Nishigo Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A power steering control device comprising a main steering means for steering a main steering wheel, a slave steering means for steering a slave steering wheel, and an electric motor for operating the slave steering means to steer the slave steering wheel. A control unit is provided that detects the steering state of the main steering wheel and the steering state of the slave steering wheel and controls the driving of the electric motor, and maintains the turning angle of the slave steering wheel at zero when the electric motor is not drive-controlled. A position holding mechanism is provided, and when the power supply to the control unit is cut off while the slave steering wheel is being steered, the electric motor is driven by the amount of electricity generated by inertial rotation until the electric motor stops. A power steering control device comprising a short-circuit circuit that shorts both terminals of the electric motor in order to prevent the electric motor from stopping abruptly and to gradually converge the turning angle of the slave steering wheels to zero.