JPH07186935A - Control device for electric negative pressure pump - Google Patents

Abstract

PURPOSE:To offer a control device for an electric negative pressure pump capable of avoiding continuous operation of the electric negative pressure pump. CONSTITUTION:A controlling pressure switch 10 is connected to a battery 3 through a motor relay 9. A constantly opened contact point 9a for the motor relay 9 is interposed in the midway of a wiring for connecting an electric motor 2 to the battery 3. A warning pressure switch 12 is connected to the battery 3 through an auxiliary motor relay 11. A constantly opened contact point 11a for the auxiliary motor relay 11 is arranged in parallel to the constantly opened contact point 9a for the motor relay 9. A timer 14 is connected to the feed circuit of the electric motor 2. The timer 14 is connected to a fail safe relay 15. The changeover contact point 15a of the fail safe relay 15 is interposed in the feed circuit of the electric motor 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electric negative pressure pump forming a part of a device for supplying a negative pressure in a vehicle brake device.

[0002]

2. Description of the Related Art A controller for an electric negative pressure pump controls an electric motor of the electric negative pressure pump. The electric motor drives an electric negative pressure pump, and the electric negative pressure pump constitutes a negative pressure supply device of the brake device together with the negative pressure accumulator. The control device for the electric negative pressure pump has a structure for controlling an electric motor for a negative pressure pump by operating a motor relay, and a normally-open contact of the motor relay is
The electric motor is inserted in the middle of the wiring that connects the motor relay and the power source, and the normally-open contact of the electric relay is closed, so that the electric motor can be energized and can be driven.

Further, a control pressure switch and an alarm pressure switch which are operated by the negative pressure of the vehicle brake device are provided. The control pressure switch is interposed in the feed circuit of the motor relay and closes the switching contact in the feed circuit of the motor relay and raises the negative pressure to the predetermined upper limit when the negative pressure drops to the predetermined lower limit. It works to open when you do.

The alarm pressure switch responds so as to close and generate an alarm signal when the negative pressure drops to a predetermined minimum pressure, and the negative pressure is lower than the switching threshold of the control pressure switch. It operates so that it opens when it rises to. And in the normal operating state of the brake device,
When the negative pressure falls to a predetermined lower limit value, the control pressure switch is turned on and the motor relay is turned on. Subsequently, the normally open contact of the motor relay is closed, so that the electric motor is energized to drive the negative pressure pump and the negative pressure is increased.

When the negative pressure rises to a predetermined upper limit value, the control switch is turned off and the motor relay is de-energized. As a result, the normally open contact of the motor relay returns to the open state, the electric motor is de-energized, and the negative pressure pump stops. By repeating the above control, the negative pressure is controlled within the predetermined operating pressure range.

At this time, when the negative pressure falls below the lower limit value and further falls below a predetermined minimum pressure due to a failure of the control pressure switch or the like, the alarm pressure switch is activated. Then, the alarm pressure switch is turned on and an alarm signal is emitted, for example, a brake alarm lamp lights up to notify the driver. At this time, if necessary, the antilock control device is partially or wholly opened so that the braking function is not significantly impaired even without antilock control.

Then, when the negative pressure rises to a predetermined limit value, the alarm pressure switch returns to the off state, the alarm signal stops, and the normal operation state is restored. Thus, the electric motor of the electric negative pressure pump is drive-controlled by the operation of the contacts of the motor relay, and the motor relay is controlled by the opening / closing operation of the control pressure switch.

However, the pressure switch is relatively prone to wear. As is generally known, relatively high cut-in and cut-out currents flow in this type of device, which can cause the pressure switch to break. When the control pressure switch is disconnected, in the control device as described above, when the negative pressure falls below a predetermined lower limit value or below a minimum pressure, the alarm switch is turned on and an alarm signal is generated. Since the electric motor is in the stopped state, the negative pressure further decreases, and it becomes impossible to secure the necessary minimum negative pressure.

For this reason, in the prior art, Japanese Patent Laid-Open No. 2-1363
As described in Japanese Patent Publication No. 65, etc., an auxiliary motor relay is provided as an energizing means. That is, an auxiliary motor relay is provided in the feed circuit of the alarm pressure switch, and the normally open contact of the auxiliary motor is provided in the middle of the wiring that connects the motor relay and the power source in parallel with the normally open contact of the motor relay. It is equipped with a fail-safe function.

By providing this fail-safe function,
Even if the negative pressure continues to decrease as the control pressure switch that is frequently opened and closed breaks down due to the disconnection of the control pressure switch and the negative pressure pump remains stopped, the negative pressure remains below the minimum pressure. At the time of decrease, the alarm pressure switch is turned on, and at the same time, the auxiliary motor relay is turned on. As a result, when the negative pressure becomes equal to or lower than the minimum pressure, the normally open contact of the auxiliary motor relay is closed, the electric motor is energized, the electric negative pressure pump is driven, and the negative pressure rises.

This prevents the negative pressure from dropping below the minimum pressure.

[0012]

SUMMARY OF THE INVENTION In the above-described conventional control device for an electric negative pressure pump, when an abnormal condition such as a normally open state occurs due to disconnection or contact failure of a control pressure switch that is frequently opened and closed. By operating the auxiliary motor relay provided as fail-safe means, a negative pressure equal to or higher than a predetermined minimum value is secured.

However, considering a case where the control pressure switch that is frequently opened and closed as described above fails due to welding or the like due to cut-in / cut-out current, and the control pressure switch fails in the normally closed state. Is fixed to the energized state and the electric negative pressure pump continues to be driven, resulting in a large power loss and a large driving noise. The present invention has been made in view of the above problems, and an object thereof is to provide a control device for an electric negative pressure pump that can avoid continuous operation of the electric negative pressure pump.

[0014]

In order to achieve the above object, in a control device for an electric negative pressure pump of the present invention, an electric motor for an electric negative pressure pump is connected to a power source through a contact of a motor relay, A control pressure switch that closes the switching contact in the feed circuit of the motor relay when the negative pressure of the vehicle brake device decreases to a predetermined lower limit value and opens when the negative pressure rises to a predetermined upper limit value, and a negative pressure Responding to close and alarm signal when the pressure drops to the minimum pressure,
In a control device for an electric negative pressure pump, which comprises an alarm pressure switch that opens when negative pressure rises to a limit value lower than a switching threshold value of the control pressure switch, the motor relay or the electric motor is connected to a power supply. A timer that is connected in the middle of the wiring and that outputs an output signal when the motor relay is continuously energized for a predetermined time or longer, and a fail-safe relay that is connected to the timer and operates by the output signal from the timer. And a normally-closed contact of the fail-safe relay interposed in the feed circuit of the motor relay or the electric motor.

At this time, the output signal of the timer may also function as an alarm signal. Further, in the control device for the electric negative pressure pump, which is connected to the alarm pressure switch and has energizing means for energizing the negative pressure pump electric motor when the alarm pressure switch is in an ON state, the fail safe is provided. It is characterized in that it has a fail-safe switch which is inserted in the feed circuit of the relay and which is opened only when the alarm pressure switch is in a closed state by a signal from the alarm pressure switch.

[0016]

When the control pressure switch that is frequently opened and closed fails in the normally closed state due to welding or the like, even if the negative pressure rises above the predetermined upper limit value, the control pressure switch will not open and will be negative. The electric motor for the piezoelectric dynamic pump remains energized. If left as it is, the negative piezoelectric dynamic pump continues to operate, resulting in energy loss.

On the other hand, with the configuration as described in claim 1, when the motor relay is continuously energized for a predetermined time or more, that is, when the timer is continuously energized for a predetermined time, the timer is activated. It operates and emits an output signal. As a result, the failsafe relay operates and the normally closed setting of the failsafe relay is opened. Then, the power supply to the electric motor is cut off and the negative piezoelectric dynamic pump is stopped, so that energy loss is avoided.

After the abnormal state occurs and the timer is driven as described above, the output signal from the timer may remain in the operating state as it is, or a predetermined negative pressure may be obtained by using another pressure switch or the like. When the following occurs, the energized state of the timer may be temporarily cut off to return the timer to the initial state. Further, as described in claim 2, by using the output signal of the timer as an alarm signal, it is possible to notify the driver of the abnormality by an alarm means such as an alarm lamp.

In addition, in the control device for the electric negative pressure pump, which is connected to the alarm pressure switch and has energizing means for energizing the negative pressure pump electric motor when the alarm pressure switch is in the ON state, If the pressure switch for operation has a normally open state due to disconnection or poor contact and the negative pressure continues to drop,
It responds so that it will be closed and an alarm signal will be generated when the pressure drops to a specified minimum pressure, and the energizing means will operate to put the electric motor in the energized state instead of the motor relay, so that the negative pressure will not fall below the specified value. Works.

At the start of driving the negative pressure pump via the electric motor due to the operation of the auxiliary motor relay, the negative pressure pump has been driven for a relatively long time because the pressure accumulation amount of the negative pressure actuator is small. Becomes That is, the energized state of the electric motor is continuously energized for a longer time than the normal state. At this time, when the timer is connected in the middle of the wiring that connects the electric motor and the power supply, there is a risk that the timer will be energized for a time longer than the set time.

When the timer is energized for more than the set time, the energization of the electric motor is cut off. Therefore, in the control device for the electric negative pressure pump, which is connected to the alarm pressure switch and has the energizing means for energizing the negative pressure pump electric motor when the alarm pressure switch is in the ON state, The alarm pressure switch is provided with a failsafe switch that is connected to the pressure switch and is interposed in the feed circuit of the failsafe relay, and that is opened only when the alarm pressure switch is closed. In the ON state, even if an output signal is output from the timer, the failsafe relay does not operate, and the contacts of the failsafe relay are held in the closed state.

[0022]

Embodiments of the present invention will be described with reference to the drawings.
First, the configuration will be described. As shown in FIG. 1, the control device S of the electric negative pressure pump 1 is interposed between an electric motor 2 of the electric negative pressure pump 1 and a vehicle battery 3 as a power source, and The drive of the electric negative pressure pump 1 is controlled via the electric motor 2.

The electric motor 2 is connected to the electric negative pressure pump 1 to drive the electric negative pressure pump 1, and the electric negative pressure pump 1
Together with the negative pressure accumulator 4 constitute a negative pressure supply device of the brake device. In this embodiment, the brake pressure generating device 6 operated by the pedal 5 includes a hydraulic booster 6a and a brake master cylinder 6b. The brake master cylinder 6b is connected to a wheel brake (not shown) via brake circuits 7a and 7b.

As shown in FIG. 1, the control device S of the electric negative pressure pump 1 of this embodiment is such that one end of a motor relay 9 is connected to the positive electrode of a battery 3 via an ignition lock 8 and the motor relay 9 is connected to the positive electrode. One contact of the control pressure switch 10 is connected to the other end of the control pressure switch 10. In addition, R is selected as a contact for connecting the motor relay 9 to the ignition lock 8. This connecting contact R indicates the switching position in the ignition lock 8 where power is supplied to the selected consumer device which does not include engine ignition.
In particular, a vehicle radio is connected to this contact R. Normally, the steering lock snaps in at the parking position P. In this switching position, parking lights, central locking systems and a few other consumer devices are also connected.

The control pressure switch 10 operates in response to the negative pressure applied to the brake pressure generator. As shown in FIG. 2, the switching contact closes immediately when it is detected that the negative pressure has dropped to a predetermined lower limit value, and immediately when it is detected that the negative pressure has risen to a predetermined upper limit value. It is controlled to be in the open state. In the control device S of this embodiment, as shown in FIG. 2, the upper limit value is set to 180 bar and the lower limit value is set to 140 bar.

The other contact side of the control pressure switch 10 is grounded. Further, a normally open contact 9a of the motor relay 9 is provided in the middle of the wiring that connects the positive electrode of the battery 3 and the electric motor 2 for an electric negative pressure pump to form a feed circuit to the electric motor 2. By closing the normally open contact 9a, the electric motor 2 can be energized.

Further, one end of an auxiliary motor relay 11 is connected to the positive electrode of the battery 3 through an ignition lock 8, and one end of an alarm pressure switch 12 is connected to the other end of the auxiliary motor relay 11. ing. In addition,
The switch-on position (Zdg.) Is selected as a contact for connecting the auxiliary motor relay 11 to the ignition lock 8.

The alarm pressure switch 12 operates in response to the negative pressure applied to the brake pressure generator. As shown in FIG. 3, the switching contact is closed immediately when it is detected that the negative pressure has dropped to a predetermined minimum value, and immediately when it is detected that the negative pressure has risen to a predetermined upper limit value. It is controlled to be in the open state. Control device S of this embodiment
Then, as shown in FIG. 2, the upper limit value is set to 130 bar and the minimum value is set to 105 bar. That is, the upper limit of the negative pressure response in the alarm pressure switch 12 is set lower than the operating pressure range set by the control pressure switch 10.

The alarm pressure switch 12 has a first switching contact 12a and a second switching contact 12b, and both switching contacts 12a and 12b operate in synchronization. One end of the first switching contact 12a is connected to the other end of the auxiliary motor relay 11, and the other end of the first switching contact 12a is connected to the alarm lamp 13 via a diode so that a negative pressure is predetermined. It is possible to notify the driver via the alarm lamp 13 that the value has dropped below the minimum value.

Further, the second switching contact 12b is normally closed, and when the negative pressure becomes sufficient, it can be connected to, for example, a brake slip control device or the like. For example, by opening the second switching contact 12b,
Set so that the anti-lock control is released. Further, the normally open contact 11a of the auxiliary motor relay 11 is parallel to the normally open contact 9a of the motor relay 9, and is interposed in the middle of the wiring connecting the positive electrode of the battery 3 and the electric negative pressure pump electric motor 2. The electric motor 2 can be energized by closing the normally open contact 11a.

The wiring forming the feed circuit to the electric motor 2 is branched and connected to one end of a timer contact forming the timer 14. The timer 14
When the current is supplied, the elapsed time start signal is set, and the timer contact is closed only when it is continuously energized for a predetermined set time. Has been done.

The set time of the timer 14 is set longer than the continuous time in which the electric motor 2 is energized / non-energized during normal operation, and is set so that the timer 14 does not operate during normal operation. ing. The other end of the timer contact is connected to the fail safe relay 15 and the alarm lamp 13.

The switching contact 15a of the fail-safe relay 15 is interposed between the normally open contact 9a of the motor relay 9 and the normally open contact 11a of the auxiliary motor relay 11 and the electric motor 2. The energization state of the electric motor 2 can be cut off. The switching contact 15a
Is a normally open contact 9a of the motor relay 9 and the auxiliary motor relay 1 when the fail-safe relay 15 is in a non-conductive state.
The normally open contact 11a of No. 1 and the electric motor 2 are connected. Further, since the fail-safe relay 15 is brought into conduction, the normally open contact 9a of the motor relay 9 and the normally open contact 11a of the auxiliary motor relay 11 are disconnected from the electric motor 2, and the motor relay 9 is also disconnected. The normally open contact 9a, the normally open contact 11a of the auxiliary motor relay 11, and one end of the timer contact are switched and connected.

Further, the first of the alarm pressure switches 12 is
A second fail-safe relay 17 forming a fail-safe switch is connected to a wiring 16 branched from the middle of the wiring connecting the switching contact 12a and the alarm lamp 13. Normally closed contact 17 of the second fail-safe relay 17
a is provided in the middle of the wiring connecting the timer 14 and the fail-safe relay 15.

In the control device S for the electric negative pressure pump having the above-described structure, in the normal operating state, the negative pressure is a predetermined lower limit value (1).
When the pressure drops to 40 bar), the control pressure switch 10 is turned on and the motor relay 9 is turned on. Then, the normally open contact 9a of the motor relay 9 is closed to energize the electric motor 2 to drive the electric negative pressure pump 1 to increase the negative pressure.

When the negative pressure rises to a predetermined upper limit value (180 bar), the control pressure switch 10 is turned off and the motor relay 9 is de-energized. As a result, the normally open contact 9a of the motor relay 9 is returned to the open state, the electric motor 2 is de-energized, and the electric negative pressure pump 1 is stopped. By repeating the above operation, the negative pressure is controlled within a predetermined operation range, that is, between 140 and 180 bar.

At this time, if the negative pressure falls below the lower limit value (140 bar) and further falls below the predetermined minimum pressure (105 bar) due to a failure of the control pressure switch 10 or the like, the alarm pressure is lowered. The switch 12 is actuated, the alarm pressure switch 12 is turned on, and an alarm signal is emitted. For example, the brake alarm lamp 13 is turned on to notify the driver of the vehicle. Depending on the setting state, the anti-lock control device is set to be partially or wholly opened so that the brake key function is not significantly impaired even without anti-lock control.

Subsequently, the negative pressure increases and the predetermined upper limit value (130
When the pressure rises to the bar), the alarm pressure switch 12 returns to the off state, the alarm signal stops, and the normal operation state is restored.
In this way, the drive motor of the pump 1 is connected to the motor relay 9
Is controlled by the normally open contact 9a of the motor relay 9a.
Is controlled by the opening / closing operation of the control pressure switch 10.

However, the pressure switch is relatively easy to wear. As is generally known, a relatively high cut-in / cut-out current flows in this type of device, which may cause the pressure switch to break or weld.
If the control pressure switch 10 that is frequently opened and closed is welded and fails in the normally closed state, the normally open contact 9a of the motor relay 9 maintains the closed state so that the electric motor 2 is in the energized state, that is, The negative pressure continues to rise as the electric negative pressure pump 1 remains driven. The motor relay 9
Even if the normally open contact 9a itself fails, the fuse is fused, or the like, a failure in which the normally open contact 9a of the motor relay 9 remains closed can occur.

At this time, the timer 14 whose set time is set to a time longer than the normal energized / non-energized state of the motor relay 9 is continuously energized for a predetermined set time or longer. , The contact of the timer 14 is closed to be in a conductive state. Then, the alarm lamp 13 is energized and the alarm lamp 13 is turned on, thereby informing the driver of abnormality.

At the same time, the fail-safe relay 15 is energized via the normally closed contact 17a of the first fail-safe relay 17. As a result, the fail safe relay 1
The switching contact 15a of No. 5 switches to stop the electric motor 2 in the non-energized state and maintain the conduction state to the timer 14. As a result, the control pressure switch 1
Abnormal increase in negative pressure due to welding of 0, etc. is avoided. In addition,
Energy loss occurs when the negative pressure continues to rise abnormally.

Further, if the control pressure switch 10 that is frequently opened and closed breaks down and fails in the normally open state, the negative pressure of the electric negative pressure pump 1 remains stopped and the negative pressure continues to decrease. The normally open contact 9a of the motor relay 9 may be broken or the fuse may be melted to cause the normally open contact 9a of the motor relay 9 to be in the open state.

When this negative pressure falls below the minimum pressure (105 bar), the alarm pressure switch 12 is turned on and the alarm lamp 13 is energized and lit. At the same time, the auxiliary motor relay 11 is turned on, the normally open contact 11a of the auxiliary motor relay 11 is closed, the electric motor 2 is turned on, the electric negative pressure pump 1 is driven, and the negative pressure is increased. .

Next, the upper limit value (130 bar) of the alarm pressure switch 12 which is lower than the normal negative pressure operation range.
When the negative pressure rises up to, the alarm pressure switch 12 is turned off again, the alarm lamp 13 is turned off, the auxiliary motor relay 11 is turned off, and the normally open contact 11a is opened. Return to the electric motor 2
Stops and the negative pressure drops.

By repeating the above-mentioned operation, while the negative pressure is maintained in a lower pressure range than the normal operation range, the warning lamp 13 is repeatedly turned on and off to notify the failure of the driver. Here, since the alarm pressure switch and the auxiliary motor relay 11 operate only when an abnormality occurs, they do not frequently perform switching operations as frequently as the control pressure switch 10 and the like, and it is considered that there are few failures.

Since the amount of accumulated pressure in the negative pressure actuator 4 is small when the negative pressure is reduced to the minimum pressure, the electric negative pressure generated by the auxiliary motor relay 11 via the electric motor 2 is reduced. At the start of driving the pump 1,
The electric negative pressure pump 1 is continuously driven for a relatively long time. That is, the electric motor 2 is continuously energized for a longer period of time than the normal state.

Therefore, if it is left as it is, the timer 14 is continuously energized for the set time or more, the switching contact 15a of the fail-safe relay 15 is switched, and the energization of the electric motor 2 is cut off. On the other hand, by providing the second fail-safe relay 17, the second fail-safe relay 17 becomes conductive when the alarm pressure switch 12 is turned on, and the second fail-safe relay 17 is normally closed. The contact 17a is opened. Thus, even if the timer 14 is in the conductive state, the fail safe relay 15 is prevented from being energized and the switching contact 15a of the fail safe relay 15 is prevented from being switched.

Further, when the alarm pressure switch 12 is in the ON state, the electric motor 2 is driven through the normally open contact 11a of the auxiliary motor relay 11 to increase the negative pressure. Therefore, when the alarm pressure switch is turned off, the second fail-safe relay 17
Is de-energized and the second fail-safe relay 17
The normally closed contact 17a returns to the closed state.

In the above embodiment, once the negative pressure is abnormally increased and the timer 14 is continuously energized for a predetermined set time, the timer 14 remains conductive. , Switching contact 1 of fail-safe relay 15
A member such as the control pressure switch is provided in the middle of the wiring connecting the battery 3 and the timer 14 by switching the switch 5a, and a mechanism or the like is provided so that the timer 14 can be cut off when the pressure falls below a predetermined pressure. You can leave it.

Next, the second embodiment will be described with reference to FIG. In FIG. 4, 100a is a low switch 100a forming a part of the control pressure switch, and 100b is a high switch 100 forming a part of the control pressure switch.
Reference numerals b and 112 are alarm pressure switches, 109 is a motor relay, and 111 is an auxiliary motor relay.

In the second embodiment, the positive electrode of the battery 103 and the electric motor 2 are connected to the normally open contact 1 of the motor relay 109.
09a. The motor relay 10
9 is connected to the battery 103 via the normally open contact 109a of the auxiliary motor relay 111. In addition, the auxiliary motor relay 111 is a low switch 1 arranged in parallel.
00a and the alarm pressure switch 112, the high switch 100b is connected in parallel with the auxiliary motor relay 111 while being connected to the positive electrode of the battery 103.

In the second embodiment, the motor relay 1
The timer 114 is connected to the 09 feed circuit, and the switching contact 115a of the fail-safe relay 115 is arranged in the middle of the wiring connecting the normally open contact 111a of the auxiliary motor relay 111 and the motor relay 109. In addition, 117 has shown the 2nd fail safe relay.

In the second embodiment, the alarm relay 13 is used.
0 is provided, and once the alarm pressure switch is turned on, the alarm lamp 113 is kept on. Then, similar to the first embodiment, the low switch 100a and the high
By opening and closing the switch 100b, the motor relay 1
The opening / closing operation of the normally open contact 109a of 09, that is, the energization / de-energization of the electric motor 102 is controlled. by this,
The drive of the electric negative pressure pump is controlled to control the negative pressure within a predetermined operating pressure range.

In this state, if the low switch 100a or the high switch 100b fails, or if the auxiliary switch fails, causing the motor relay 109 to be constantly energized, the timer 114 exceeds the preset time. It is continuously energized and the timer 114 becomes conductive. As a result, at the same time that the alarm lamp 113 is turned on, the fail-safe relay 115 is turned on and the switching contact 115a of the fail-safe relay 115 is switched.
The motor relay 109 is de-energized and the electric motor 1
02, and the electric negative pressure pump is stopped.

If the low switch 100a or the high switch 100b fails and remains in the normally open state,
When the negative pressure continues to decrease and reaches the predetermined minimum pressure, the alarm pressure switch 1112 operates and the alarm lamp 113 lights up, and the auxiliary motor relay 111 is energized.
That is, the motor relay 109 is turned on. This prevents the negative pressure from dropping below the minimum pressure.

At this time, when the negative pressure is reduced to the minimum pressure, the amount of accumulated pressure in the negative pressure actuator is also small. Therefore, the operation of the auxiliary motor relay 111 causes the electric negative pressure via the electric motor 102. At the start of driving the pump 1, the electric negative pressure pump 1 is continuously operated for a relatively long time.
Is driven. That is, the energized state of the electric motor 2 is continuously energized for a longer time than in the normal state.
By equipping the second fail-safe relay 117, when the alarm pressure switch 112 is turned on, the second fail-safe relay 117 becomes conductive and the normally-closed contact 17a of the second fail-safe relay 117 is opened. It becomes a state. As a result, even if the timer 114 is in the conductive state, the power supply to the fail-safe relay 115 is cut off, and the switching contact 1 of the fail-safe relay 115 is cut off.
Switching of 15a is avoided.

Further, when the alarm pressure switch 112 is ON, the electric motor 2 is driven through the normally open contact 111a of the auxiliary motor relay 11 to increase the negative pressure, and the alarm pressure switch 12 has an upper limit value or more. As a result, when the alarm pressure switch is turned off, the second fail-safe relay 117 is de-energized and the normally closed contact 117a of the second fail-safe relay 117 is returned to the closed state.

Other configurations, operations and effects are similar to those of the first embodiment.

[0059]

As described above, in the control device for the electric negative pressure pump of the present invention, the negative pressure is prevented from lowering to the minimum pressure or lower due to the stop of the electric negative pressure pump caused by the disconnection of the pressure switch or the like. In addition, the energy loss that rises to a negative pressure above a predetermined operating range of the electric negative pressure pump due to the sticking of a pressure switch or the like is suppressed, the fail safe function is improved, and the reliability of the control device of the electric negative pressure pump is improved. Moreover, the reliability of the braking device is improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a control device for an electric negative pressure pump according to an embodiment of the present invention.

FIG. 2 is a diagram showing ON / OFF positions of control pressure switches in the control device for the electric negative pressure pump according to the embodiment of the present invention.

FIG. 3 is a diagram showing ON / OFF positions of alarm pressure switches in the control device for the electric negative pressure pump according to the embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing a control device for an electric negative pressure pump according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Electric Negative Pressure Pump 2 Electric Motor 3 Battery 4 Negative Pressure Accumulator 9 Motor Relay 9a Normally Open Contact 10 Control Pressure Switch 11 Auxiliary Motor Relay 11a Normally Open Contact 12 Alarm Pressure Switch 13 Alarm Lamp 14 Timer 15 Failsafe Relay 15a Switching Contact 17 Second fail-safe relay 17a Normally closed contact

Claims (3)

[Claims] 1. A switch in a feed circuit of a motor relay when an electric motor for an electric negative pressure pump is connected to a power source through a contact of a motor relay and the negative pressure of a vehicle brake device decreases to a predetermined lower limit value. A control pressure switch that closes the contact and opens when the negative pressure rises to a predetermined upper limit value, and closes when the negative pressure drops to a predetermined minimum pressure and responds to generate an alarm signal. In a control device for an electric negative pressure pump equipped with an alarm pressure switch that opens when the pressure rises to a limit value lower than the switching threshold of the pressure switch, connect the motor relay or the electric motor to the middle of the wiring connecting the power supply. The motor relay outputs an output signal when the motor relay is continuously energized for a predetermined period of time or more, and is connected to the timer to operate by the output signal from the timer. And a normally-closed contact of the fail-safe relay interposed in the feed circuit of the motor relay or the electric motor, and a controller for an electric negative pressure pump. 2. The control device for an electric negative pressure pump according to claim 1, wherein the output signal of the timer also serves as an alarm signal. 3. A control device for an electric negative pressure pump, comprising: an energizing device connected to the alarm pressure switch to energize a negative pressure pump electric motor when the alarm pressure switch is in an on state. A fail safe switch is provided which is interposed in the feed circuit of the fail safe relay and which is opened only when the alarm pressure switch is closed by a signal from the alarm pressure switch. A control device for an electric negative pressure pump according to claim 1 or 2.