JP3186277B2 - Motor control circuit in power steering system for ship propulsion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering system for a watercraft propulsion system in which hydraulic oil is supplied to a hydraulic cylinder unit for swinging a steering arm of a watercraft propulsion system such as an outboard motor by a motor and a hydraulic pump. The present invention relates to a motor control circuit based on a position of a spool in a device.

[0002]

2. Description of the Related Art As a power steering device of a marine propulsion device, a hydraulic pump is supplied to a hydraulic cylinder unit that swings a steering arm by using a power of an engine of a ship. And the like, which is performed by a hydraulic pump such as the one described above.

[0003]

However, when the power of the engine is used as in the above-described conventional power steering apparatus, the engine output rotates the hydraulic pump even when the steering by the power steering apparatus is not performed. And engine power loss occurs.

[0004] In this case, it is conceivable that the hydraulic pump is driven to rotate by a motor and the motor is driven only during steering. However, in this case, the start-up delay of the motor when shifting from non-steering to steering is considered. It takes time for the hydraulic pump to reach the power assist state,
The responsiveness of the power steering device deteriorates.

Therefore, for example, the position of the spool valve for switching the supply path of the hydraulic oil to the hydraulic cylinder unit in conjunction with the operation of the steering wheel, that is, the spool valve is neutral (neutral)
It detects whether or not the vehicle has moved from the position (non-steering state) to the steering state, and according to the detection result, the electric motor is rotated at a low speed during non-steering, and is rotated at a high speed when shifting to the steering state. It is conceivable that the hydraulic pump can be brought into the power assist state in a short time when shifting from the non-steering state to the steering state while preventing loss of engine power during non-steering. .

Incidentally, it is conceivable to detect the position of the spool valve by using a contact type sensor such as a limit switch or a non-contact type sensor such as a proximity sensor for detecting the position of the spool valve. Complexity and cost.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a motor current detecting means for detecting a current flowing through a motor, and comparing a detected value of the motor current detecting means with a predetermined set value. Determining means for determining the position of the spool valve;

[0008]

When the spool valve is moved from the neutral position to the steering state, and when returning from the steering state to the neutral position, the load applied to the motor fluctuates and the current value flowing to the motor changes. By detecting the value and comparing the detection result with a predetermined set value to determine the position of the spool valve, the position of the spool valve can be detected without using a sensor. The movement of the spool valve can be detected.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a hydraulic circuit diagram of a power steering device of an outboard motor to which a spool position detecting device according to the present invention is applied. The power steering device includes a hydraulic cylinder unit 1 for swinging a steering arm and a hydraulic cylinder unit 1. And a spool valve section 2 for switching the supply path of the hydraulic oil.

The hydraulic cylinder unit 1 is defined by a piston 4 attached to the base end of the rod 3 into an oil chamber S1 on the side where the rod 3 is not inserted and an oil chamber S2 on the side where the rod 3 is inserted. Then, by supplying / discharging hydraulic oil to / from these oil chambers S1 and S2, the rod 3 is expanded and contracted to swing the steering arm that swings the outboard motor.

The spool valve 2 is moved via a cable 5 or the like in conjunction with the operation of the handle, and is moved to a neutral position 2c.
When the hydraulic cylinder unit 1 is at the first position 2a, the supply of the hydraulic oil to the hydraulic chamber S1 is shut off. When the hydraulic cylinder unit 1 is at the second position 2b, the hydraulic oil is supplied to the oil chamber S1. The supply path is switched so that hydraulic oil is supplied to the oil chamber S2 of the unit 1.

A hydraulic pressure generator for supplying hydraulic oil to the hydraulic cylinder unit 1 rotates a hydraulic pump 12 with a motor 11 to
The hydraulic oil is sucked through the hydraulic pump unit 12 and supplied to the spool valve 2 via the valve 15 through the hydraulic oil pump 12 and the hydraulic cylinder unit 1 according to the position of the spool valve 2.
The hydraulic oil is supplied to the oil chamber S1 or S2.

As shown in FIG. 2, a drive control circuit of a motor 11 for rotatingly driving the hydraulic pump 12 includes a battery 2
An FET (field effect transistor) 22 is interposed in the power supply path from the motor 1 to the motor 11, and a PWM (pulse width modulation) drive circuit 23 for controlling the on / off of the FET 22 is provided. A diode 24 is connected, and a key switch 25 is interposed in a power supply path from the battery 21 to the PWM drive circuit 23.

A current detector 26 is interposed between the FET 22 and the ground to detect a current flowing through the motor 11,
A determination circuit 27 is provided which receives the output of the current detector 26 and compares it with a predetermined set value to determine whether or not the spool valve 2 is at the neutral position. The output is input to the PWM drive circuit 23, and the PWM drive circuit 23 changes the on-duty according to the determination output.

The determination circuit 27 amplifies a detection output from the current detector 26 by a non-inverting amplifier including an operational amplifier OP1 and resistors R1 and R2, as shown in FIG. 3, to generate a detection voltage V1. The voltage V1 is compared with the first set voltage Va generated by dividing the voltage by the resistor R3 and the resistor R4 by the comparator COM1.
The output of OM1 is output to a capacitor C via a parallel circuit composed of a resistor R5, a resistor R6, a diode D1 and a resistor R7 and a diode D2. The second set voltage Vb is compared with the second set voltage Vb.

Then, a first set voltage Va generated by voltage division by the resistors R3 and R4 is input to the output terminal side of the comparator COM2 via the resistor R10 and the diode D3, and the output of the comparator COM2 and the first set voltage are output. Va
And outputs the result to the PWM drive circuit 23 via the diode D4 and the resistor R11.

In the determination circuit 27, the motor 11
When the motor 11 is rotating at low speed with no load and the detection voltage V1 is lower than the first set voltage Va, the first set voltage Va is output to the PWM drive circuit 23, and the motor 11 that is rotating at low speed with no load is driven.
When the detection voltage V1 rises and becomes equal to or higher than the first set voltage Va due to a load applied to the comparator COM2,
Of the PWM drive circuit 23 by setting the output of
% On-duty, and outputs the PWM drive circuit 2 even when the motor 11 is rotating at high speed with a load.
3. Continue to output the voltage to make 100% on duty,
When the motor 11 having the high-speed rotation with the load becomes the no-load high-speed rotation, the output of the comparator COM2 is set to “L”, the first set voltage Va is output to the PWM drive circuit 23, and the motor 11 is no-load. Return to low speed rotation.

In the power steering apparatus configured as described above, when the key switch 25 is turned on and the engine is operating, and when the spool valve 2 is in the neutral (neutral) position and the steering is not performed, the motor current is reduced. A determination circuit 27 based on the detection value of the current detector 26 to be detected
Is determined to be in a non-steering state, and the first set voltage Va is output to the PWM drive circuit 23 as a control voltage.
The drive circuit 23 reduces the duty ratio of the ON state (for example, 50%) when controlling the ON / OFF of the FET 22.
%).

[0019] Thus, the motor 11 is driven to rotate at a low speed is supplied with electric power corresponding to the on-duty of the FET 22, for example, the motor 11 as shown in FIG. 4 flows the motor current of a current value I _1.

In this state, when the steering wheel is operated to move the spool valve 2 to the first position 2a or the second position 2b to be in the steering state, the hydraulic oil discharged from the hydraulic pump 12 passes through the spool valve 2. The hydraulic oil is supplied to one oil chamber of the hydraulic cylinder unit 1, and the hydraulic oil returns from the other oil chamber of the hydraulic cylinder unit 1 to the tank 13 to move the piston 4. 11 is also loaded, for example, at time T ₁ shown in FIG.
Motor current value from the increases from the current value I ₁ of the no-load low-speed rotation.

Therefore, the judgment circuit 27 compares the detected value I of the motor current from the current detector 26 with the first set value Ia,
When ≧ Ia, that is, when the detection voltage V1 becomes equal to or higher than the first set voltage Va, the output of the comparator COM2 is set to “H” to output the steering state detection signal to the PWM drive circuit 2.
3 so that the PWM drive circuit 23
2 is controlled to an on-duty ratio of 100%, that is, an always-on state.

As a result, the motor 11 is rotated at a high speed with 100% output, and the hydraulic pump 12 is driven to rotate at full power to generate a steering assist force, and supplies hydraulic oil to the hydraulic cylinder unit 1. At this time, the motor current flowing through the motor 11 becomes a current value I _2.

When the spool valve 2 is returned to the neutral position by operating the handle 5 from a state where the hydraulic cylinder unit 1 is operated by rotating the motor 11 at a high speed, the hydraulic oil from the hydraulic pump 12 since the load of the hydraulic pump 12 is the load of the motor 11 is also reduced to decrease so the process returns to the tank 13 via a valve 12, for example, from the time T ₂ shown in FIG. 4, the motor current is a load-speed rotation It decreases from the current value I ₂ in current value Ib of the no-load high-speed rotation.

Therefore, the judgment circuit 27 compares the detected value I of the motor current from the current detector 26 with a second set value Ib which is set slightly higher than the current value during no-load high-speed rotation.
b, that is, when the motor enters the no-load high-speed rotation state, the output of the comparator COM2 is set to "L" again to output the first set voltage Va to the PWM drive circuit 23. Therefore, the PWM drive circuit 23 50% again
, The motor 11 is switched from the high-speed rotation to the low-speed rotation.

As described above, the motor current flowing through the motor 11 that rotationally drives the hydraulic pump 12 is detected, and the motor current increases or decreases in accordance with a change in load accompanying the movement of the spool valve 2. Since the value is compared with the set value to determine whether the position of the spool valve 2 is the non-steering position or the steering position, the detecting device is mechanically simple, and the position of the spool valve 2 is detected stably and with high accuracy. it can.

When the motor 11 for driving the hydraulic pump 12 is rotated at a low speed even during non-steering, the motor is switched to the steering state, and when supply of hydraulic oil by the hydraulic pump becomes necessary, The time required for the start-up of the motor 11 is shortened, the responsiveness of the power steering device is improved, and the motor 11 is rotationally driven at a lower speed (lower output) than during steering when the vehicle is not being steered, so that engine output loss is suppressed. be able to.

When the key switch 25 is turned off and the engine is stopped, the PWM drive circuit 2
3 is deactivated and the FET 22 is fixed to the off state, so that the motor 11 stops and the battery 21 does not consume power.

[0028]

According to the present invention as described above,
The value of the current flowing to the motor that rotates the hydraulic pump is detected, and the position of the spool valve is determined based on the detection result. Therefore, the position of the spool valve can be detected without using a sensor, and the position of the spool valve can be detected with high accuracy. In addition, the movement of the spool valve can be stably detected.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a power steering device of an outboard motor to which a spool position detecting device according to the present invention is applied.

FIG. 2 is a block diagram of a motor drive control circuit of the power steering device.

FIG. 3 is a circuit diagram of a determination circuit of FIG. 2;

FIG. 4 is a diagram for explaining the motor drive control circuit;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hydraulic cylinder unit, 2 ... Spool valve, 11 ... Motor, 12 ... Hydraulic pump, 23 ... PWM drive circuit,
26 ... current detector, 27 ... judgment circuit.

Claims (1)

(57) [Claims] A hydraulic oil supply to a hydraulic cylinder unit for swinging a steering arm of a marine propulsion device is switched by a spool valve operated in conjunction with a handle operation, and the hydraulic cylinder unit is rotated by a motor. In a power steering apparatus configured to supply hydraulic oil by a hydraulic pump to be driven, a motor current detection unit that detects a current flowing through the motor and a detection value of the motor current detection unit are compared with a predetermined set value. A motor control circuit in a power steering device for a marine propulsion device, comprising: a determination unit configured to determine a position of the spool valve.