JP2021130337A - Steering force control device and vehicle - Google Patents

Abstract

To provide a steering force control device and a vehicle capable of assisting steering force when hydraulic pressure is lost in a hydraulic power steering device.SOLUTION: A steering force control device is to control a vehicular steering device that includes: a hydraulic power steering device; an input shaft of the hydraulic power steering device which has one end connected to a steering shaft; a motor that applies rotational force to the input shaft; a first detecting unit that detects steering torque; and a second detecting unit that detects a steering angle. This steering force control device includes: a determining unit that determines whether or not the steering torque detected by the first detecting unit is equal to or greater than a first threshold, and whether or not the steering angle detected by the second detecting unit is equal to or smaller than a second threshold; and a control unit that actuates the motor when the steering torque is equal to or greater than the first threshold, and the steering angle is equal to or smaller than the second threshold.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a steering force control device and a vehicle.

Conventionally, there is known a hydraulic power steering device that assists the steering force of a vehicle by supplying hydraulic oil pumped by a pump to a hydraulic cylinder connected to a steering mechanism (see, for example, Patent Document 1). ..

Japanese Unexamined Patent Publication No. 2016-168878

However, there is a problem that the steering force cannot be assisted when the oil pressure is lost in the hydraulic power steering device.

An object of one aspect of the present disclosure is to provide a steering force control device capable of assisting a steering force when a hydraulic pressure is lost.

The steering force control device according to one aspect of the present disclosure includes a hydraulic power steering device, an input shaft of the hydraulic power steering device having one end connected to a steering shaft, and a motor that applies a rotational force to the input shaft. A steering force control device that controls a vehicle steering device including a first detection unit that detects steering torque and a second detection unit that detects steering angle, and is detected by the first detection unit. A determination unit that determines whether the steering torque is equal to or greater than the first threshold value and the steering angle detected by the second detection unit is equal to or less than the second threshold value, and the steering torque is equal to or greater than the first threshold value. Yes, and when the steering angle is equal to or less than the second threshold value, it has a control unit for operating the motor.

The vehicle according to one aspect of the present disclosure includes a steering force control device according to one aspect of the present disclosure.

According to the present disclosure, the steering force can be assisted when the oil pressure is lost.

Schematic diagram showing an example of the configuration of the steering device according to the embodiment of the present disclosure. A block diagram showing an example of the configuration of the steering force control device according to the embodiment of the present disclosure. A flowchart showing an example of the operation of the steering force control device according to the embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The components common to each figure are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

The configuration of the steering device 100 according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic view showing an example of the configuration of the steering device 100.

The steering device 100 is mounted on a vehicle such as a commercial vehicle. The steering device 100 is, for example, a rack and pinion type.

The motor 1 and the hydraulic power steering device 2 are provided below the floor portion F of the vehicle interior.

The motor 1 is, for example, a motor used in an electric power steering device for a passenger car. The motor 1 is electrically connected to a steering force control device 200 (see FIG. 2; not shown in FIG. 1), which will be described later. The operation of the motor 1 is controlled by the steering force control device 200.

The output shaft of the motor 1 is fixed to the first pulley 31 of the speed reducer 3. In addition to the first pulley 31, the speed reducer 3 has a second pulley 32 fixed to the pinion shaft 4 and a belt 33 wound around the first pulley 31 and the second pulley 32. The diameter of the second pulley 32 is larger than the diameter of the first pulley 31.

The rotational force of the motor 1 is applied to the pinion shaft 4 via the speed reducer 3. In other words, the motor 1 applies a rotational force to the pinion shaft 4 via the speed reducer 3. The pinion shaft 4 corresponds to an example of the “input shaft of the hydraulic power steering device”.

One end of the pinion shaft 4 is connected to one end of the steering shaft 6 via a cardan joint 5. The other end of the steering shaft 6 is fixed to the steering wheel 7 on which the steering operation is performed by the driver.

The other end of the pinion shaft 4 is inserted into the hydraulic cylinder 11 of the hydraulic power steering device 2. A pinion gear 4a is provided on the other end side of the pinion shaft 4. The pinion gear 4a meshes with the rack gear 8a provided on the rack shaft 8. As a result, the rotational motion of the pinion shaft 4 is converted into a reciprocating linear motion in the axial direction of the rack shaft 8 via the pinion gear 4a and the rack gear 8a. In FIG. 1, the arrow A indicates the rotation direction of the pinion shaft 4 and the steering shaft 6, and the arrow B indicates the axial direction of the rack shaft 8.

The reciprocating linear motion of the rack shaft 8 is transmitted to the wheels 10 via tie rods 9 connected to both ends of the rack shaft 8. As a result, the steering angle of the wheel 10 is changed.

The steering shaft 6 is provided with a steering angle sensor 20. The pinion shaft 4 is provided with a steering torque sensor 30. The steering angle sensor 20 and the steering torque sensor 30 are electrically connected to the steering force control device 200. The steering torque sensor 30 corresponds to an example of the "first detection unit", and the steering angle sensor 20 corresponds to an example of the "second detection unit".

The steering angle sensor 20 periodically detects the rotation angle of the steering wheel 7 (which may be referred to as the steering shaft 6), and controls the detected rotation angle value (hereinafter, referred to as the detected steering angle). Output to device 200.

The steering torque sensor 30 periodically detects the rotational torque of the steering wheel 7 (which may be referred to as the pinion shaft 4), and controls the detected rotational torque value (hereinafter, referred to as the detected steering torque). Output to device 200.

As shown in FIG. 1, the hydraulic power steering device 2 includes a hydraulic cylinder 11, a reservoir tank 13, a pump 14, and a valve device 15.

The hydraulic cylinder 11 includes a piston 12 inside the hydraulic cylinder 11. The piston 12 is fixed to the rack shaft 8 and can move in the axial direction of the rack shaft 8 (see arrow B).

The inside of the hydraulic cylinder 11 is divided into a hydraulic chamber 11a and a hydraulic chamber 11b by the piston 12.

The reservoir tank 13 stores hydraulic oil. The reservoir tank 13 is connected to the pump 14 and the valve device 15 via a pipe 16.

The pump 14 pumps hydraulic oil from the reservoir tank 13. The pump 14 operates by obtaining a driving force from, for example, an internal combustion engine (not shown) of a vehicle. The pump 14 is connected to the reservoir tank 13 and the valve device 15 via a pipe 16.

The valve device 15 switches so that the hydraulic oil pumped by the pump 14 is supplied to the hydraulic chamber 11a or the hydraulic chamber 11b according to the rotation direction of the pinion shaft 4 (see arrow A). The valve device 15 is connected to the reservoir tank 13, the pump 14, the hydraulic chamber 11a, and the hydraulic chamber 11b via the pipe 16.

In the hydraulic power steering device 2, the hydraulic oil pumped from the reservoir tank 13 by the pump 14 is supplied to the valve device 15. The hydraulic oil supplied to the valve device 15 is supplied to either the hydraulic chamber 11a or the hydraulic chamber 11b.

For example, when the hydraulic oil is supplied to the hydraulic chamber 11a, the hydraulic oil is discharged from the hydraulic chamber 11b. Further, for example, when the hydraulic oil is supplied to the hydraulic chamber 11b, the hydraulic oil is discharged from the hydraulic chamber 11a. The hydraulic oil discharged from the hydraulic cylinder 11 is returned to the reservoir tank 13 via the valve device 15.

As a result, the rack shaft 8 moves in the axial direction (see arrow B) together with the piston 12. As a result, the steering force is assisted.

The configuration of the steering device 100 has been described above.

Next, the configuration of the steering force control device 200 according to the embodiment of the present disclosure will be described with reference to FIG. FIG. 2 is a block diagram showing an example of the configuration of the steering force control device 200.

The steering force control device 200 is mounted on a vehicle equipped with the steering device 100 shown in FIG.

As shown in FIG. 2, the steering force control device 200 has a determination unit 201 and a control unit 202.

Although not shown, the steering force control device 200 includes, for example, a CPU (Central Processing Unit), a storage medium such as a ROM (Read Only Memory) storing a control program, and a working memory such as a RAM (Random Access Memory). And has a communication circuit. The functions of the determination unit 101 and the control unit 102, which will be described later, are realized by the CPU executing a computer program.

The determination unit 201 periodically receives the detected steering torque from the steering torque sensor 30 and the detected steering angle from the steering angle sensor 20. Then, the determination unit 201 determines whether or not the detected steering torque is equal to or greater than the first threshold value and the detected steering angle is equal to or less than the second threshold value.

The first threshold value and the second threshold value are set based on the result of an experiment or simulation on what combination of steering torque and steering angle causes a flood control in the hydraulic power steering device 2. NS.

When the determination unit 201 determines that the detected steering torque is equal to or greater than the first threshold value and the detected steering angle is equal to or less than the second threshold value, the control unit 201 gives an operation start instruction to the motor 1. As a result, the operation of the motor 1 is started, and the steering force is assisted.

The configuration of the steering force control device 200 has been described above.

Next, the operation of the steering force control device 200 will be described with reference to FIG. FIG. 3 is a flowchart showing an example of the operation of the steering force control device 200.

The flow shown in FIG. 3 is started, for example, at the start of traveling of the vehicle, and is repeated while the vehicle is traveling.

In step S1, the determination unit 201 determines whether or not the detected steering torque received from the steering torque sensor 30 is equal to or greater than the first threshold value and the detected steering angle received from the steering angle sensor 20 is equal to or less than the second threshold value. judge.

When the detected steering torque is not equal to or greater than the first threshold value and at least one of the cases where the detected steering angle is not equal to or less than the second threshold value is applicable (step S1: NO), the flow ends.

When the detected steering torque is equal to or greater than the first threshold value and the detected steering angle is equal to or less than the second threshold value (step S1: YES), the flow proceeds to step S2.

In step S2, the control unit 202 gives an operation start instruction to the motor 1 to start the operation of the motor 1.

The operation of the steering force control device 200 has been described above.

As described in detail so far, the steering force control device 200 is characterized in that the motor 1 is operated when the detected steering torque is equal to or greater than the first threshold value and the detected steering angle is equal to or less than the second threshold value. .. As a result, the steering force can be assisted in the case where the flood pressure is lost in the hydraulic power steering device 2.

The steering device 100 of the present embodiment can obtain the following effects.

Since the steering device 100 is provided below the floor portion F of the vehicle interior, the layout of the vehicle interior can be improved.

Further, the motor 1 is a motor used in an electric power steering device for a passenger car. Therefore, an off-the-shelf product can be used as the motor 1, and the manufacturing cost of the motor 1 can be suppressed. Further, since the motor used in the electric power steering device for a passenger car is relatively small, the degree of freedom in the installation space of the motor 1 is improved.

Further, by using the speed reducer 3, the rotational force of the motor 1 applied to the pinion shaft 4 can be further increased.

The present disclosure is not limited to the description of the above embodiment, and various modifications can be made without departing from the spirit of the present embodiment. Hereinafter, a modified example will be described.

[Modification 1]
In the embodiment, the case where the motor 1 is a motor of an electric power steering device for a passenger car has been described as an example, but the present invention is not limited to this, and other motors may be used.

[Modification 2]
In the embodiment, the case where the speed reducer 3 is provided with a pulley has been described as an example, but the present invention is not limited to this, and a speed reducer provided with gears may be used.

[Modification 3]
In the embodiment, the case where the steering device 100 is a rack and pinion type has been described as an example, but the present invention is not limited to this, and the steering device 100 may be a ball screw type.

Each modification has been described above. In addition, each modification may be carried out in combination.

The steering force control device and the vehicle of the present disclosure are useful for all the techniques for assisting the steering force.

1 Motor 2 Hydraulic power steering device 3 Reducer 4 Pinion shaft 4a Pinion gear 5 Cardan joint 6 Steering shaft 7 Steering wheel 8 Rack shaft 8a Rack gear 9 Tie rod 10 Wheel 11 Hydraulic cylinder 11a, 11b Hydraulic chamber 12 Piston 13 Reservoir tank 14 Pump Valve device 16 Piping 20 Steering angle sensor 30 Steering torque sensor 31 1st pulley 32 2nd pulley 33 Belt 100 Steering device 200 Steering force control device F Floor of passenger compartment

Claims (5)

Steering: a hydraulic power steering device, an input shaft of the hydraulic power steering device whose one end is connected to a steering shaft, a motor that applies a rotational force to the input shaft, a first detection unit that detects steering torque, and steering. A steering force control device that controls a vehicle steering device including a second detection unit that detects an angle.
A determination unit that determines whether or not the steering torque detected by the first detection unit is equal to or greater than the first threshold value and the steering angle detected by the second detection unit is equal to or less than the second threshold value.
It has a control unit for operating the motor when the steering torque is equal to or higher than the first threshold value and the steering angle is equal to or lower than the second threshold value.
Steering force control device. The hydraulic power steering device, the input shaft, and the motor are provided below the floor of the passenger compartment.
The steering force control device according to claim 1. The motor is connected to the input shaft via a speed reducer.
The steering force control device according to claim 1 or 2. The motor
A motor used in electric power steering devices for passenger cars.
The steering force control device according to any one of claims 1 to 3. A vehicle provided with the steering force control device according to any one of claims 1 to 4.

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