JPH05162651A - Motor-driven power steering device - Google Patents

Abstract

PURPOSE:To provide a motor-driven power steeing preventing the lowering of battery capacity and the burning of a steering motor, a control circuit, and the like by locking the control circuit at the time of no operation being performed by an operator, thereby stopping the flow of a current to the steering motor. CONSTITUTION:When operation is not performed for the specified time so as to judge an operator to have no operating will a power steering control circuit 22 is locked to stop current application to a steering motor 23. This can eliminate the continuous flow of a minute current to the steering motor 23. Afterwards, when operation is resumed or when steering torque applied to a steering wheel 11 is detected to be the specified value or more by a torque sensor 10, the lock is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a battery fork vehicle,
The present invention relates to a control device for an electric power steering device mounted on an electric vehicle or the like.

[0002]

2. Description of the Related Art Conventionally, in a battery fork vehicle or the like equipped with an electric power steering device, when a key switch is inserted, the steering motor is always controllable regardless of the operator's willingness to drive,
Even when the operator has no intention of driving and the steering wheel is not turned, a small amount of current may flow through the steering motor.

[0003]

In particular, in a vehicle of a type having a long distance from the steering wheel operation unit to the motor drive unit, such as a picking lift in which an operator rides on a lift to drive or a three-wheel counterbalance type forklift. Is a path for transmitting the steering wheel operation, the neutral return of the sensor that detects the steering torque is bad due to the influence of mechanical loss, etc., the rotation command remains, the current continues to flow to the steering motor, and the battery capacity decreases. May lead to burnout of the steering motor, control circuit, etc.

The present invention solves the above-mentioned problems. When the operator does not intend to drive, the control circuit is locked to prevent current from flowing to the steering motor, thereby reducing the battery capacity and steering motor. An object of the present invention is to provide an electric power steering device that can prevent the control circuit and the like from being burnt out.

[0005]

In order to achieve the above object, the present invention provides a sensor for detecting a steering torque applied to a steering wheel, a steering motor for operating a steering wheel, and a drive of the motor according to the sensor output. In an electric power steering apparatus having a control circuit for controlling the driving, a detection means for detecting the presence or absence of a driving operation by an operator, and a driving operation when a driving operation is not performed for a predetermined time or more based on the detection result of the detection means, Locking means for determining that there is no intention and locking the control circuit to stop driving of the motor, and the detecting means detecting that the driving operation is performed again after being locked by this locking means, Alternatively, a lock release means is provided for releasing the lock of the lock means when the sensor output exceeds a predetermined value. It is intended.

[0006]

According to the above construction, when it is determined that the driving operation is not performed for a predetermined time by the detecting means and it is determined that the operator does not intend to drive, the locking means locks the control circuit to operate the steering wheel. Stop energizing the motor. This prevents a minute current from continuing to flow through the steering motor forever. After that, when it is determined that the driving operation is performed again by the detection means and it is determined that the operator has a driving intention, or when the steering torque of the steering wheel detected by the sensor becomes equal to or more than a predetermined value, the lock is released. By means of the means, the lock of the locking means is released, and the power supply to the steering motor is started. This allows normal operation.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a forklift truck according to an embodiment of the present invention. The vehicle body 1 has a drive wheel 2 and a steering wheel 3 having a steering action, and a driving force from a traveling motor 4 is transmitted to the drive wheel 2 via a speed reducer 5. An instruction from the accelerator pedal 7 is input to the control device 6 through the accelerator operation detecting device 8, and the torque sensor 1
Steering wheel 11 for steering detected by 0
The steering torque signal is input to perform predetermined traveling control.
In addition, 12 is a battery. Further, the steering wheel 23 is driven by the steering motor 23.

FIG. 2 shows a block configuration around the control device. The travel control circuit 21 in the control device 6 receives the command signal of the accelerator pedal 7 that is input via the accelerator operation detection device 8 and outputs a predetermined drive command signal to the travel motor 4 to drive the drive wheel 2 Drive control. Further, the power steering control circuit 22 in the control device 6 receives the steering torque signal applied to the steering wheel 11 via the torque sensor 10, and the steering motor 23
The steering control of the steered wheels 3 is performed by outputting a predetermined steering command signal to.

The control device 6 has a time counter 24, a lock circuit 25, a setting circuit 26, and a comparison circuit 27 in addition to the travel control circuit 21 and the power steering control circuit 22. The time counter 24 counts the time during which no driving operation is performed by the operator. The lock circuit 25 is the power steering control circuit 2
2 is a circuit that locks 2 and stops the power supply to the steering motor 23. The setting circuit 26 is a circuit that sets the value of the steering torque signal that is applied to the steering wheel 11 and is necessary for releasing this lock. The comparison circuit 27 is
The set value by the setting circuit 26 and the torque sensor 10
It is a circuit for comparing with a steering torque detection signal from. The accelerator operation detecting device 8 and the time counter 24 are
It constitutes a detection means for detecting the presence or absence of a driving operation by an operator.

Next, the operation of the above configuration will be described. In normal operation, when the operator operates the steering wheel 11, the torque sensor 10 detects the steering torque applied to the steering wheel 11. This detection signal is input to the power steering control circuit 22, and the steering motor 23 is controlled accordingly. Steering motor 23
As a result, the steering wheel 3 is driven by steering. The traveling motor 4 is controlled by the traveling control circuit 21, and the drive wheels 2 are driven to travel by the traveling motor 4.

The presence / absence of the driving operation by the operator is detected by the presence / absence of the operation of the accelerator pedal 7. When the accelerator pedal 7 is not operated, this time is counted by the time counter 24. When the time measured by the time counter 24 exceeds a certain value, it is determined that the operator has no intention of driving, the lock circuit 25 locks the power steering control circuit 22, and the power supply to the steering motor 23 is stopped. As a result, no current flows through the steering motor 23.

After that, when the accelerator pedal 7 is operated again, it is determined that the operator has a driving intention, the value of the time counter 24 is reset, and the lock circuit 25 releases the lock applied to the power steering control circuit 22. By doing so, energization of the steering motor 23 is started, and normal operation can be performed. When the operator turns the steering wheel 11, the steering torque applied to the steering wheel 11 is detected by the torque sensor 10, and the steering torque detection signal is used as a comparison circuit 27.
At, the value is compared with the value set by the setting circuit 26.
Then, when the steering torque detection signal becomes larger than the set value, the steering motor 23 is started to be energized and the normal operation can be performed, as described above.

As means for detecting the presence / absence of a driving operation by an operator, in addition to the means for detecting the presence / absence of an accelerator operation in the above-mentioned embodiment, a switch attached to a seat on the vehicle and a handle 11 are provided. A touch sensor or the like can also be used. The present invention is not limited to the case of the forklift truck of the above embodiment, but can be variously applied as long as it is a vehicle equipped with the electric power steering device.

[0014]

As described above, according to the present invention, in a battery fork vehicle equipped with an electric power steering device, when it is detected that there is no driving operation by the operator, the control circuit is locked. Stop energizing the steering motor. This allows
The current flowing through the steering motor disappears, and it is possible to prevent the battery capacity from decreasing and the steering motor, the control circuit, and the like from burning. After that, when a driving operation is performed again by the operator, the lock can be released to start energizing the steering motor and return to the normal operation.

[Brief description of drawings]

FIG. 1 is a side view of a forklift truck according to an embodiment of the present invention.

FIG. 2 is a block configuration diagram around a control device.

[Explanation of symbols]

 3 Steering Wheels 6 Control Device 7 Accelerator Pedal 8 Accelerator Operation Detection Device 10 Torque Sensor 22 Power Steering Control Circuit 23 Steering Motor 24 Time Counter 25 Lock Circuit

Claims (1)

[Claims] 1. An electric power steering apparatus having a sensor for detecting a steering torque applied to a steering wheel, a steering motor for operating a steering wheel, and a control circuit for controlling driving of the motor according to an output of the sensor. A detecting means for detecting the presence or absence of a driving operation by an operator, and when the driving operation is not performed for a predetermined time or longer based on the detection result of the detecting means, it is judged that there is no driving intention and the control circuit is locked to lock the motor. And a lock means for stopping the driving of the drive means, and the detection means detects that the driving operation is performed again after being locked by the lock means, or when the sensor output exceeds a predetermined value, the An electric power steering device comprising lock releasing means for releasing the lock of the lock means.