JPH0243826Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a power supply control for an electric power steering vehicle that controls to reduce the load on the vehicle battery according to the operation of the power steering device in a vehicle equipped with an electric power steering device. It is related to the device.

In general, power steering devices installed in vehicles usually change the amount of reduction in steering force depending on the vehicle speed. In a high vehicle speed range, the amount of reduction is gradually reduced as the vehicle speed increases, and the steering force is gradually increased. In order to obtain such steering force reduction amount characteristics, the electric motor of the electric power steering device, that is, the electric motor that drives the oil pump that supplies pressure oil to the power cylinder, or the
As disclosed in Publication No. 55-44058, a large current is supplied to the electric motor that directly drives the steering mechanism (rack bar, pinion, etc.) in the low vehicle speed range below a predetermined speed, but in the medium to high vehicle speed range above the predetermined speed. Then, it is necessary to supply a small current that gradually decreases from the above-mentioned large current.

However, if we look at this state from the perspective of discharging the onboard battery, the amount of discharge is large in the low vehicle speed range where the engine speed is low and the amount of charge is low, and conversely, the amount of discharge is large in the high vehicle speed range where the engine speed is high and the amount of charge is large. The amount of discharge is decreasing. For this reason, there is a risk of over-discharging of the vehicle's battery in the low vehicle speed range where the power steering system should be fully functioning, especially when pulling out of the garage or parallel parking, and the electric power steering system is not fully functioning. I was disappointed that there were times when I couldn't do it.

Therefore, conventional technologies to prevent over-discharging of the vehicle's battery include idling up the engine when the headlights are turned on, and forcing the operation of the defogger for defogging the window glass when the electric fan for forced cooling of the radiator is activated. A system has been proposed that stops the
54-64823, Utility Model Application Publication No. 51-50128, etc.). However, these devices are only intended to prevent over-discharge of a vehicle battery, and cannot be used immediately as a measure to prevent over-discharge of a vehicle battery caused by the operation of an electric power steering device.

The present invention was developed in view of the above, and detects when the electric motor of an electric power steering device is under high load. The purpose of this is to prevent over-discharging of the vehicle battery when the operation is forced to stop, and to allow the electric power steering device to fully perform its functions at low vehicle speeds, such as when pulling out of the garage.

In order to achieve this objective, the present invention provides a vehicle equipped with an electric power steering device in which the steering mechanism is driven by an electric motor. The load reduction device is activated to reduce the load on the vehicle battery.

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

FIG. 1 shows the overall schematic configuration of an electric power steering device, in which 1 and 1 are left and right wheels, 2 is a steering wheel, and the steering wheel 2 has a steering shaft 3, a pinion gear 4, a rack shaft 5 having a rack 5a, and a left and right wheel. tie rod 6,
The rack shaft 5 is connected to the left and right wheels 1, 1 via the left and right knuckle arms 7, 7, and the rack shaft 5 is moved in the left-right direction of the vehicle body in response to the rotational operation of the steering wheel 2. It is configured to steer in a predetermined direction.

Reference numeral 8 denotes a power cylinder having a piston 8a fixed to the center of the rack shaft 5;
It has a first oil chamber 8b and a second oil chamber 8c which are defined on the left and right by a, and each oil chamber 8b, 8c is supplied with pressure oil via a first oil passage 9a and a second oil passage 9b, respectively. It is connected to a control valve 10 that switches direction, and the control valve 10 is connected to an oil pump 13 via an oil supply path 11 and an oil return path 12. The control valve 10 is connected to the oil supply path 1 when the steering wheel 2 is in the neutral position.
1 and the oil return path 12, and when steering the steering wheel 2, the oil supply path 11 is connected and communicated with the first oil path 9a or the second oil path 9b in accordance with the rotational operation direction of the steering wheel 2, and The other oil passage 9b or 9a is connected and communicated with the oil return passage 12. Therefore, when the gear shaft 5 moves to the right or left in the figure as the steering wheel 2 is operated in a predetermined rotational direction, the pressure oil discharged from the oil pump 13 is transferred from the oil supply path 11 to the first oil path 9a.
Or the first oil of the power cylinder 8 via the second oil passage 9b.
By supplying the oil to the oil chamber 8b or the second oil chamber 8c, the above-mentioned gear shaft 5 is supplied via the piston 8a.
to the right or left in the diagram and turn the steering wheel 2.
It is designed to assist the steering force of the vehicle.

Further, the oil pump 13 includes a
An electric motor 14 is connected to the electric motor 14, and a controller 15 is connected to the electric motor 14. The controller 15 controls the motor 14 according to the driving state of the vehicle (vehicle speed and whether or not the steering wheel 2 is turned). . A vehicle speed sensor 16 that detects the vehicle speed and a steering sensor 17 that detects whether or not the steering wheel 2 is being turned are connected to the controller 15, and its internal configuration is as shown in FIG. a frequency-voltage converter 18 that converts a vehicle speed signal (a pulse signal with a frequency proportional to the vehicle speed) from the vehicle speed sensor 16 into a voltage signal;
A triangular wave generating circuit 19 that generates a triangular wave, and a triangular wave signal from the triangular wave generating circuit 19 at the above frequency -
A first comparator 20 generates a duty signal corresponding to the vehicle speed (a signal whose duty ratio decreases as the vehicle speed increases) by comparing it with the vehicle speed signal expressed as a voltage from the voltage converter 18, and the electric motor 14 The idle duty signal generation circuit 21 generates an idle duty signal for idling, and the first
The duty signal corresponding to the vehicle speed from the comparator 20 is received via the first AND circuit 22 and the ON operation is performed. On the other hand, when the steering signal from the steering sensor 17 is not generated (that is, when the steering wheel 2 is not being steered), the above-mentioned The power supply transistor 24 receives the idle duty signal from the idle duty signal generation circuit 21 via the second AND circuit 23 and turns ON to control the amount of power supplied to the electric motor 14. When the steering wheel 2 is not being steered, the idle duty signal from the idle duty signal generation circuit 21 turns on the power supply transistor 24 to idle control the electric motor 14, while when the steering wheel 2 is being steered, the first comparator 20
The power supply transistor 24 is turned ON by the duty signal according to the vehicle speed from the electric motor 1.
The power supply current to 4 is gradually reduced as the vehicle speed increases.

Inside the controller 15, there is a resistor R interposed in the power supply circuit 14a of the electric motor 14.
A power supply current detection circuit 25 is connected to both ends of the electric motor 14 to detect the power supply current of the electric motor 14, and an idle up relay 2 which increases the engine speed at idle
A normally open contact 27a interposed in the excitation circuit 26a of No. 6
A first control relay 27 is provided. The above-mentioned power supply current detection circuit 25 is connected to the electric motor 1
When the power supply current value of No. 4 is larger than the reference current value I ₀ , a high load detection device is generated and the first transistor 28 interposed in the excitation circuit 27b of the first control relay 27 is turned on. Therefore, the power supply current detection circuit 25 constitutes a first high load detection device 29 that determines the magnitude of the power supply current value of the electric motor 14 and detects when the electric motor 14 is under high load. When the first transistor 28 is turned on in response to the generation of the high load detection signal of the power supply current detection circuit 25, the first control relay 27 is turned on, its normally open contact 27a is closed, and the idle up relay 26 is turned on. The first model was designed to reduce the load on the vehicle battery by increasing the engine speed at idle.
This constitutes a battery load reduction device 30.

Further, inside the controller 15, a voltage signal is received from the frequency-voltage converter 18, and is compared with a reference voltage value corresponding to a predetermined vehicle speed V set by a reference value setting device 31 to generate a reference voltage. a second comparator 32 that issues a low vehicle speed signal when the speed is below the value;
and a high load detection AND circuit 33 which receives the low vehicle speed signal from the second comparator 32 and the steering signal from the steering sensor 17 and generates a high load detection signal.
, a second control relay 36 having a normally closed contact 36a interposed in the power supply circuit 35a of the defogger 35 for defogging window glass, which is supplied with power from the vehicle battery 34, and the AND circuit 33 for high load detection. When the high load detection signal is received, the second
and a second transistor 37 that turns on the control relay 36 of. Therefore, the predetermined vehicle speed V
When the steering wheel 2 is steered at the following low vehicle speeds, a high load detection signal is generated from the high load detection AND circuit 33 to detect a high load on the electric motor 14. Device 3
8, and when the second transistor 37 is turned on in response to the generation of the high load detection signal of the high load detection AND circuit 33, the second control relay 36 is turned on and its normally closed contact is turned on. 36
A and the power supply circuit 35a of the defogging defogger 35 are opened, thereby constituting a second battery load reduction device 39 that reduces the load on the vehicle battery 34. In FIG. 2, 40 is a key switch, and 41 is a switch for operating the defogging defogger 35.

Next, the operation of the above embodiment will be explained in relation to changes in vehicle speed from when the vehicle starts until it reaches a predetermined high vehicle speed.

First, when the steering wheel 2 is not being steered when the vehicle is stopped, the idle duty signal generating circuit 21 is connected to the power supply transistor 24 of the electric motor 14.
An idle duty signal is input from the electric motor 14, and the electric motor 14 is idle-controlled even with a power supply current value smaller than the reference current value _I0 . Therefore, a high load detection signal is not generated from the power supply current detection circuit 25, and the AND circuit 3 for detecting high load is not generated.
3, the high load detection signal is not generated as the steering sensor 17 does not generate a steering signal. As a result, the engine speed is maintained at a steady state, and the defogging defogger 35 continues to operate while its operating switch 41 is closed.

Now, when starting the vehicle while steering the steering wheel 2, the output of the idle duty signal to the power supply transistor 24 is blocked due to the generation of the steering signal from the steering sensor 17, and at the same time, the output of the idle duty signal to the power supply transistor 24 is blocked.
A duty signal having a large duty ratio corresponding to the vehicle speed is input to the power supply transistor 24. At this time, if the steering resistance is high, the electric motor 14
begins to be driven with a power supply current value larger than the reference current value _I0 , and the oil pressure generated by the oil pump 13 increases accordingly, and the steering force of the steering wheel 2 is greatly reduced by the power cylinder 8. At this time, a high load detection signal is generated in the power supply current detection circuit 25 due to the power supply to the electric motor 14 that is larger than the reference current value _I0 , and therefore the first transistor 28 is turned ON, and then the first transistor 28 is turned on. Control relay 27 turns ON and its normally open contact 27
a is closed, the idle up relay 26 is turned on, and the engine speed is increased at idle. At the same time, a high load detection signal is generated from the high load detection AND circuit 33 due to the low vehicle speed signal from the second comparator 32 and the steering signal from the steering sensor 17, and the second transistor 37 is accordingly turned on. The second control relay 36 is activated.
The normally closed contact 36a opens and the power supply circuit 35a of the defogging defogger 35 is forcibly opened. As a result, in-vehicle battery 3
The load of No. 4 is greatly reduced by increasing the engine speed at idle and forcibly opening the power supply circuit 35a of the defogging defogger 35. Therefore, by significantly reducing the battery load, it is possible to prevent over-discharge of the on-vehicle battery 34 caused by power supply larger than the reference current value _I0 to the electric motor 14, and the function of the electric power steering device can be reduced to a low speed range. This can be particularly effective when pulling out of the garage or parallel parking.

In the above case, when the steering resistance is low and the current supplied to the electric motor 14 is _I0 or less, the first battery load reducing device 30 does not operate, and only the second battery load reducing device 39 operates. I will do it.

After the vehicle speed reaches the predetermined vehicle speed V, the current supplied to the electric motor 14 also decreases to below the reference current value I ₀ as the duty ratio of the duty signal according to the vehicle speed decreases. Therefore, the amount of steering force assistance for the steering wheel 2 by the power cylinder 8 gradually decreases as the vehicle speed increases, and the steering force for the steering wheel 2 gradually increases. At this time, the power supply current detection circuit 25 stops generating the high load detection signal when the power supply current to the electric motor 14 decreases below the reference current value _I0 . Also, at the same time,
When the second comparator 32 stops generating the low vehicle speed signal, the high load detection AND circuit 33 stops generating the high load detection signal. As a result, the idle-up relay 26 turns off the first control relay 27.
When activated, the OFF operation stops the idle increase in engine speed, and the normally closed contact 36a of the second control relay 36 closes to enable the defogger 35 to operate, reducing the load on the vehicle battery 34. The condition will return to steady state.

In the above embodiment, when the electric motor 14 is under high load, the operation of the defogging defogger 35 is forcibly stopped to reduce the load on the vehicle battery 34. It goes without saying that the load on the on-vehicle battery 34 may be reduced by forcibly stopping a battery that consumes energy and whose operation does not interfere with safe driving of the vehicle even if the operation is forcibly stopped.

Furthermore, in the above embodiment, as specific means for reducing the load on the vehicle battery 34, both the forced stop of the defogging defogger 35 and the idle increase of the engine speed are used. In-vehicle battery 3
Needless to say, the load on 4 can be reduced. However, it is more preferable to do as in this embodiment because the load can be effectively reduced.

As explained above, according to the present invention, in a vehicle equipped with an electric power steering device in which a steering mechanism is driven by an electric motor, a high load detection device detects when the electric motor is under high load. Since the battery load reduction device is activated to reduce the load on the vehicle battery, it is possible to prevent over-discharge of the vehicle battery when the electric motor is under high load, thereby improving the functionality of the electric power steering device. This can be fully utilized at low vehicle speeds, such as when driving out of the garage.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall schematic configuration diagram of an electric power steering device, and FIG.
The figure is an electrical circuit diagram showing the internal configuration of the controller. 8... Power cylinder, 13... Oil pump, 14... Electric motor, 25... Power supply current detection circuit, 26... Idle up relay, 27...
First control relay, 29...First high load detection device, 30...First battery load reduction device, 32
...Second comparator, 33...AND circuit for high load detection, 34...Vehicle battery, 35...Defogger for defogging, 36...Second control relay, 3
8...Second high load detection device, 39...Second battery load reduction device.

Claims (1)

[Scope of utility model registration request] In a vehicle equipped with an electric power steering device in which a steering mechanism is driven by an electric motor, a high load detection device detects when the electric motor is under high load, and a detection signal from the high load detection device is used to drain the vehicle battery. A power supply control device for an electric power steering vehicle, comprising a battery load reduction device that operates to reduce a load.