JPH05162631A - Load controller for vehicle - Google Patents

Abstract

PURPOSE:To improve the durability of a relay in a load controller for vehicle where relays to be excited and controlled at the time of controlling electric load by the controller are provided in series to the electric load. CONSTITUTION:A semi-conductor relay 32 where an electric field effect transistor Q1 and a diode D1 are connected in parallel is provided at a system controller 24, the source side of the electric field effect transistor Q1 is connected to an electromagnetic valve driving coil 30, and the power source voltage of an external power source 33 is applied to the drain side. Besides, an electric field effect transistor Q2 for exciting and controlling the electromagnetic valve driving coil 30 is provided at the system controller 24, and the drain side of the transistor Q2 is connected to the electromagnetic valve driving coil 30 through a check diode D3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric load control device provided in a vehicle.

[0002]

2. Description of the Related Art With the development of electronics in recent years, various control systems in vehicles are rapidly becoming electronic.

Taking a brake system as an example, an anti-skid brake system may be provided for the purpose of preventing the wheels from locking or skiding during sudden braking (see, for example, Japanese Patent Laid-Open No. 169357). ). This anti-skid brake system has
In general, a wheel speed sensor that detects the rotational speed of the wheel, an electromagnetic control valve that supplies and discharges brake hydraulic pressure, and a system controller 24 that controls the electromagnetic control valve are provided, and are detected by the wheel speed sensor, for example. When the wheel deceleration calculated based on the wheel speed becomes smaller than a predetermined value, the electromagnetic control valve is pressure-reduced and the rotational speed of the wheel released due to the decrease in the brake hydraulic pressure increases to increase the wheel speed. The electromagnetic control valve is configured to be pressure-increased when the wheel acceleration calculated on the basis of the predetermined value reaches a predetermined value. As a result, the wheels are prevented from being locked or skided during sudden braking, and the vehicle can be stopped at a short braking distance without impairing directional stability.

By the way, in this type of anti-skid brake system, when the electromagnetic control valve is fixed in the open state of the brake hydraulic pressure, for example, when an abnormal signal is input to the system controller 24 during execution of brake control, the brake pedal is depressed. However, the brake oil pressure is not supplied to the brake device.

For this reason, an anti-skid brake system of this kind is provided with an electromagnetic relay 103 having a movable contact 102 which is opened and closed by the operation of an exciting coil 101, as shown in FIG. 9, for example.
3 movable contact 101 and electromagnetic control valve drive coil 104
And a control transistor 106 for brake control provided in the system controller 105 are connected in series, and a main transistor 107 for turning the electromagnetic relay 103 on and off by the system controller 105 and the exciting coil 101 are provided. It is designed to be installed in series.

Therefore, when the brake control is executed, the main transistor 107 is driven by the drive signal output from the CPU 108 provided in the system controller 105.
Turns on and the exciting coil 101 of the electromagnetic relay 103
Is energized, whereby the movable contact 102 is closed and the solenoid valve drive coil 104 becomes energizable. By turning on the control transistor 106 for brake control in this state, a current flows through the solenoid valve drive coil 104 and the solenoid control valve actually operates. On the other hand, when the movable contact 102 is opened, even if the control transistor 106 is turned on, the solenoid valve drive coil 1
No current flows through 04, and the electromagnetic control valve becomes inoperative. As a result, even if a malfunction occurs in the system controller 105 and a drive signal that constantly maintains the operating state is output to the solenoid valve drive coil 104, when the electromagnetic relay 103 is in the OFF state, the electromagnetic control valve is actually used. Does not work, and good fail-safe performance will be obtained.

[0007]

However, in the relay of the type having the movable contact as described above, since the connecting / disconnecting operation is mechanically performed, not only the transient response has a problem but also the contact deterioration is caused. It may cause malfunction.

To solve such a problem, it is possible to abolish the relay, but this causes a problem in terms of fail-safety as described above.

This kind of problem occurs uniformly in the case where an electric load is controlled by a controller and an electromagnetic relay is provided for fail-safe.

According to the present invention, there is provided a vehicle in which a fail-safe relay having an electric load controlled by a controller and whose energization is controlled when the controller controls the electric load is provided in series with the electric load. The present invention addresses the above problems in a load control device, and aims to improve the control response and the durability of this type of relay.

[0011]

That is, a load control device for a vehicle according to claim 1 of the present application has an electric load controlled by a controller, and a power supply control is performed when the electric load is controlled by the controller. In a load control device for a vehicle in which a safe relay is provided in series with the electric load, the fail-safe relay is a semiconductor relay.

The load control device for a vehicle according to claim 2 of the present application is characterized in that, in the structure of claim 1, a semiconductor relay is built in the controller.

According to a third aspect of the present invention, a load control device for a vehicle has an electric load controlled by a controller, and a fail-safe relay that is energized and controlled when the controller executes the control of the electric load. In a vehicle load control device provided in series with a load, the fail-safe relay is configured by a semiconductor relay, and a backflow prevention unit is provided in a load circuit communicating with the electric load.

According to a fourth aspect of the present invention, the load control device for a vehicle according to the third aspect is characterized in that the backflow preventing means is provided in the load circuit upstream of the electric load.

[0015]

That is, according to the load control device for a vehicle according to the first to fourth aspects, since the semiconductor relay is adopted as the fail-safe relay, the control response is improved and
Since the semiconductor relay does not have a mechanical contact portion, durability is improved.

In particular, according to the load control device of the second aspect, since the semiconductor relay is built in the controller, this type of load control device can be made compact.

Further, according to the load control device of the third aspect, since the load circuit communicating with the electric load is provided with the backflow preventing means such as a diode, the driving power source of the electric load is connected with the polarity reversed. Even if it does, backflow to the electrical load will be prevented, which will further improve the reliability of the system.

According to the vehicle load control device of the fourth aspect, since the backflow prevention means is installed in the load circuit upstream of the electric load, a plurality of electric loads controlled independently of each other are provided. Even when the two are provided in parallel, the backflow at the time of reverse connection can be dealt with by providing one backflow prevention means.

[0019]

EXAMPLES Examples of the present invention will be described below.

As shown in FIG. 1, in the vehicle according to this embodiment, the left and right front wheels 1 and 2 are drive wheels, the left and right rear wheels 3 and 4 are driven wheels, and the output torque of the engine 5 is It is adapted to be transmitted from the automatic transmission 6 to the left and right front wheels 1, 2 through the differential device 7 and the left and right drive shafts 9, 10.

The wheels 1 to 4 have disks 11a to 14a which rotate integrally with the wheels 1 to 4, respectively.
And calipers 11b to 14b to which brake hydraulic pressure is supplied
And the like, and a brake control system for operating these brake devices 11 to 14 is provided.

This brake control system includes a booster 1 for increasing the stepping force on the brake pedal 15 by the driver.
6 and a master cylinder 17 that generates a brake hydraulic pressure according to the stepping force increased by the booster 16. Then, the first and second brake lines 18a and 18b connected to the master cylinder 17 respectively.
The pump 1 driven by the engine 5 respectively.
Brake oil pressurized by 9 and 19 is supplied, and check valves 20 and 20 for preventing backflow are provided in the brake lines 18a and 18b, respectively, and check valves 20 and 20 are provided downstream of the check valves 20 and 20, respectively. Pressure control valves 21 and 21 for adjusting the line pressure to a pressure corresponding to the master cylinder pressure are installed, respectively.

The first brake line 18a is connected to branch lines 22a and 22b leading to the braking devices 11 and 14 of the left front wheel 1 and the right rear wheel 4, respectively, and the second brake line 18b is connected to the right brake line 18b. Branch lines 22c and 22d are connected to the brake devices 12 and 13 of the front wheel 2 and the left rear wheel 3, respectively. Electromagnetic control valves 23a to 23d for supplying and discharging brake oil are installed on the branch lines 22a to 22d, respectively.

Further, the brake control system is provided with a system controller 24 for controlling the electromagnetic control valves 23a-23d, respectively. The system controller 24 detects a stepped state of the brake pedal 15 by a brake switch 25. Brake signals from the wheel and wheel speed sensors 26-2 for detecting the rotation speeds of the wheels 1-4.
9 and the wheel speed signals from 9 are input, and the electromagnetic control valves 23a to 23d are controlled to be supplied and discharged in accordance with these signals. Here, focusing on the electromagnetic control valve 23a for the left front wheel in FIG. 1, when the electromagnetic valve drive coil 30 provided in the control valve 23a is not energized, as shown in the figure, the brake device 11 is operated via the electromagnetic control valve 23a. And the first brake line 18a are held in communication with each other. Therefore, when the brake pedal 15 is depressed, the corresponding brake hydraulic pressure is supplied to the brake device 11. On the other hand, when the solenoid valve drive coil 30 is energized, the branch line 22a communicating with the brake device 11 is communicated with the drain line 31, which allows the brake device 11 to operate.
The brake hydraulic pressure that acts on is released.

As shown in FIG. 2, the system controller 24 in the first embodiment is provided with a semiconductor relay 32 in which a first field effect transistor Q ₁ and a diode D ₁ are connected in parallel, This semiconductor relay 3
2, the source side of the first field effect transistor Q ₁ is connected to the anode side of the solenoid valve drive coil 30 (only one is shown), and the power source voltage of the external power source 33 is applied to the drain side of the transistor Q _1. It is supposed to be done. The CPU 3 provided in the system controller 24 is provided on the gate side of the first field effect transistor Q _1.
The main control voltage V ₁ output from the No. 4 is input via the first output signal line 35. The diode D ₁ is connected in reverse connection between the source and drain of the first field effect transistor Q ₁ .

On the other hand, the system controller 24 has
Second electric field for controlling energization of the solenoid valve drive coil 30
Effect transistor Q₂Is provided, and the transistor Q₂
The source side of is body-grounded. And this first
2 Field effect transistor Q₂Between the source and drain of
Diode D in reverse connection₂Is connected and
Transistor Q₂Output from the CPU 34 to the gate side of
Electromagnetic control valve drive voltage V ₂Via the second output signal line 36
And then input.

In this embodiment, the drain side of the second field effect transistor Q ₂ is connected to the cathode side of the solenoid valve drive coil 30 via the backflow prevention diode D ₃ in the forward connection state.

Further, in this embodiment, the first,
A protection circuit 37 for protecting the second field effect transistors Q ₁ and Q ₂ is provided.

This protection circuit 37 has a Zener diode D _T connected to the drain side of the second field effect transistor Q ₁ via a resistor R _1, and the anode side of this Zener diode D _T has a resistor R ₂ . It is body grounded through. Here, the voltage division ratio of the first and second field effect transistors Q ₁ and Q ₂ is set so that a voltage exceeding the break voltage is applied to the Zener diode D _T when the solenoid valve drive coil 30 is short-circuited. ing.

Then, between the Zener diode D _T and the resistor R ₂ provided on the downstream side, the collector side of the first transistor Tr ₁ whose emitter side is body-grounded,
Similarly, the emitter side is connected to the base side of the second transistor Tr ₂ whose body is grounded. The collector side of the second transistor Tr ₂ has the second output signal line 36.
It is connected to the.

Further, the protection circuit 37 includes a resistor R ₃
A timer circuit 38 including a capacitor C and a capacitor C is provided, and the hydraulic control voltage V ₂ is input to the timer circuit 38 via an inverter 39. And
The output voltage V ₃ of the timer circuit 38 is the first transistor Tr ₁
Applied to the base side of.

Next, the operation of this embodiment will be described.

That is, as shown in FIG. 3A, at time t ₁ when a predetermined slip control condition is satisfied, the main control voltage V ₁ is turned on from low level to high level. As a result, the first field effect transistor Q ₁ is turned on from the OFF state as shown in FIG.

At time t ₂ when the wheel deceleration calculated based on the wheel speed signal becomes lower than a predetermined value, the electromagnetic control valve drive voltage V ₂ is changed as shown in FIGS.
Is switched from low level to high level,
As a result, the second field effect transistor Q ₂ is turned on. As described above, since both the first and second field effect transistors Q ₁ and Q ₂ are turned on,
As shown in FIG. 5, the solenoid valve drive current I ₁ flows through the solenoid valve drive coil 30.

On the other hand, the electromagnetic control valve drive voltage V ₂ becomes low level through the inverter 39, and the timer circuit 3 is provided between the inverter 39 and the first transistor Tr _1.
8 is provided, the output voltage V ₃ of the timer circuit 38 is maintained at the high level as shown in FIG. 3 (e). Therefore, the first transistor T
r ₁ is a predetermined timer time T ₀ , as shown in FIG.
Is maintained until the timer time T ₀
At the time point t ₃ when the time elapses, the vehicle tries to turn off. In this case, when the solenoid valve drive coil 30 is not short-circuited, the voltage applied to the Zener diode D _T does not reach the break voltage, so that the voltage effect due to the resistor R ₂ does not occur, and as shown in FIG. Even after the timer time T ₀ has elapsed, the second transistor Tr ₂ is maintained in the OFF state even after the first transistor Tr ₁ is turned off. This turns on the second field effect transistor Q ₂ .
The state is also maintained, and the solenoid valve drive current I ₁ continues to flow.

On the other hand, as shown by the chain line in FIG. 4, when the solenoid valve drive coil 30 is short-circuited, the applied voltage of the Zener diode D _T becomes larger than the break voltage, and the resistance as shown in FIG. A Zener current I _T flows through R ₂ . Therefore, as shown in FIGS. 5A and 5B, the timer time T ₀ elapses from the time point t ₄ when the electromagnetic control valve drive voltage V ₂ is switched to the high level and the second field effect transistor Q ₂ is turned on. Then, at that time point t ₅ , FIG.
As shown in (d), the first transistor Tr ₁ is turned off, and at the same time, the second transistor Tr ₂ is turned on. As a result, the gate voltage of the second field effect transistor Q ₂ is lowered and turned off, whereby the solenoid valve drive coil 30 is turned off and the first and second field effect transistors Q ₁ and Q ₁ due to overcurrent are generated. ₂ damage will be prevented.

Further, as shown in FIG. 6, a solenoid valve drive coil
External power supply 33 Was connected after reversing the sign
Also, the solenoid valve drive coil 30 and the second field effect transistor
Dista Q₂Backflow prevention diode D interposed between₃To
Therefore, the power supply to the solenoid valve drive coil 30 should be cut off.
become.

Next, a second embodiment of the present invention will be described.

That is, also in this second embodiment,
7, the system controller 24^' The electric field
Effect transistor Q_FourAnd diode D_FourAnd are connected in parallel
Terare semiconductor relay 32^'This semiconductor is provided
Relay 32^'Field effect transistor Q in_FourSeo
The source side is a field effect transistor that constitutes the backflow prevention circuit 40.
Dista Q_FiveConnected to the drain side of the
Dista Q_FiveSolenoid valve drive coil 30 on the source side^' Anno
It is designed to be connected to the power supply side. In this case
Also, the semiconductor relay 32^'Field effect transformer
Dista Q₃The drain side of the external power supply 33^'Connected to
It And these field effect transistors Q₃, Q_Fourof
CPU34 on the gate side^' Main control voltage output from
Pressure V₁Is the first output signal line 35^'Respectively entered via
It has become so.

The diode D ₄ constituting the semiconductor relay 32 ^′ is connected in the reverse connection state between the source and drain of the field effect transistor Q ₃ . On the other hand, a backflow prevention diode D ₅ is connected in a forward connection state between the source and drain of the field effect transistor Q ₄ constituting the backflow prevention circuit 40.

Further, the system controller 24^'Has
The solenoid valve drive coil 30^'Electric field for controlling the energization of
Effect transistor Q_FiveIs provided, and the transistor Q_Five
The source side of is body-grounded. And this electric
Field effect transistor Q_FiveReverse connection between the source and drain of
Diode D in the state₆Connected to the
Register Q_FiveCPU34 on the gate side of^'Is output from
Electromagnetic control valve drive voltage V ₂Is the second output signal line 36^'Through
It is supposed to be entered.

According to this structure, unless the field effect transistor Q ₃ forming the semiconductor relay 32 ^′ is turned on, the solenoid valve drive coil 30 ^′ is not energized and the control reliability is ensured. Will be.

Moreover, as shown in FIG. 7, the solenoid valve drive coil
IL 30_'Against external power supply 33^'Are connected by reversing the sign
Even if it does, the diode installed in the backflow prevention circuit 40
De D_FiveIs in the reverse connection state, the solenoid valve drive coil 30^' What
The current will be cut off.

In particular, by providing the backflow prevention diode D ₅ on the upstream side of the solenoid valve drive coil 30 ^′ as in this embodiment, one diode can be used regardless of the number of solenoid valve drive coils 30 ^′. become.

Incidentally, only the diode D ₅ may be provided.

Of course, the present invention is not limited to the brake control system as in the embodiment.

[0047]

As described above, according to the vehicle load control system of the present invention, the semiconductor relay is used as the fail-safe relay, so that the control response is improved and the semiconductor relay has a mechanical contact portion. There is also no durability, which means that durability is improved.

Particularly, according to the load control device of the second aspect, since the semiconductor relay is built in the controller, this type of load control device can be made compact.

Further, according to the load control device of the third aspect, the load circuit leading to the electric load is provided with the reverse current preventing means such as a diode, so that the drive power source of the electric load is connected with the polarity reversed. In this case, however, backflow to the electric load is prevented, which further improves the reliability of the system.

According to the vehicle load control device of the fourth aspect, since the backflow prevention means is installed in the load circuit upstream of the electric load, a plurality of electric loads controlled independently of each other are provided. Even when the two are provided in parallel, the backflow at the time of reverse connection can be dealt with by providing one backflow prevention means.

[Brief description of drawings]

FIG. 1 is a brake control system diagram of a vehicle to which the present invention is applied.

FIG. 2 is a partial configuration diagram of an electronic control circuit according to the first embodiment.

FIG. 3 is a time chart diagram showing an operating state of the electronic control circuit under normal conditions.

FIG. 4 is a partial configuration diagram of an electronic control circuit showing an operating state of a protection circuit when a load is short-circuited.

FIG. 5 is a time chart diagram showing an operating state of the electronic control circuit when the load is short-circuited.

FIG. 6 is a partial configuration diagram of an electronic control circuit showing an operating state of a backflow prevention diode at the time of reverse connection.

FIG. 7 is a partial configuration diagram of an electronic control circuit according to a second embodiment of the present invention.

FIG. 8 is a partial configuration diagram of an electronic control circuit showing an operating state of a backflow prevention diode at the time of reverse connection.

FIG. 9 is an explanatory diagram of conventional problems.

[Explanation of symbols] 23a Electromagnetic control valve 23b Electromagnetic control valve 23c Electromagnetic control valve 23d Electromagnetic control valve 24 System controller 30 Electromagnetic control valve drive coil 32 Semiconductor relay D ₃ Backflow prevention diode

Claims (4)

[Claims] 1. A fail-safe relay that has an electric load controlled by a controller and that is energized when the controller controls the electric load.
A load control device for a vehicle provided in series with the electric load, wherein the fail-safe relay is a semiconductor relay. 2. The load control device for a vehicle according to claim 1, wherein the semiconductor relay is built in the controller. 3. A fail-safe relay having an electric load controlled by a controller, wherein energization is controlled when the controller controls the electric load.
A load control device for a vehicle provided in series with the electric load, wherein the fail-safe relay is constituted by a semiconductor relay, and a backflow preventing means is provided in a load circuit communicating with the electric load. A load control device for a vehicle characterized by being provided. 4. The load control device for a vehicle according to claim 3, wherein the backflow preventing means is provided in a load circuit upstream of the electric load.