JP4986971B2 - Brake device - Google Patents

Description

  The present invention relates to a brake device having a brush motor for driving a pump.

Patent Document 1 discloses a technique for monitoring a voltage between motor terminals when the motor is not driven and determining that the motor is abnormal when the voltage between the terminals exceeds a threshold value.
Japanese Patent Laid-Open No. 2003-9586

  However, in the above prior art, when a DC brush motor is used as the motor, the temporary resistance value due to the copper oxide film (cuprous oxide film) adhered between the brush and the commutator (commutator). There was a problem of misjudging the increase as a motor abnormality.

  The objective of this invention is providing the brake device which can prevent the misjudgment of motor abnormality.

In order to achieve the above object, in the brake device of the present invention, the voltage between the terminals of the motor when the motor is not energized is detected, and if the detected voltage value exceeds a predetermined threshold, it is determined that the motor is in an abnormal state. while driving the motors energized a predetermined time to the motor, when the motor operating history of after the ignition switch is turned on is stored energizes a predetermined time to the motor even when it is determined that the abnormal state It is determined that the motor is abnormal.

  Therefore, the brake device of the present invention can prevent erroneous determination of motor abnormality.

  Hereinafter, the best mode for realizing the brake device of the present invention will be described based on an embodiment shown in the drawings.

First, the configuration will be described.
FIG. 1 is a hydraulic circuit diagram of the brake device according to the first embodiment. The brake device according to the first embodiment includes a motor, a pump, a solenoid valve, a sensor, and the like, as well as a master cylinder M / C and a wheel cylinder W /. This is an electromechanically integrated brake booster composed of a hydraulic unit 31 interposed between the hydraulic unit 31 and a control unit CU that is integrally attached to the hydraulic unit 31 and controls each element. Note that the configuration is not limited to a mechanical / electrical integrated configuration, and the hydraulic unit 31 and the control unit CU may be configured separately and are not particularly limited.

The hydraulic circuit according to the first embodiment has a piping structure called an X piping composed of two systems, a P system and an S system.
The P system is connected to the wheel cylinder W / C (FL) for the left front wheel and the wheel cylinder W / C (RR) for the right rear wheel. The wheel cylinder W / C (FR) for the right front wheel is connected to the S system. The wheel cylinder W / C (RL) on the left rear wheel is connected. Each of the P system and the S system is provided with a pump PP and a pump PS, and the pump PP and the pump PS are driven by one electric motor (hereinafter referred to as a motor) M. In the first embodiment, a DC brush motor is used as the motor M.

  The brake pedal BP is provided with a brake switch BS that detects the operation state of the brake pedal BP. The brake pedal BP is connected to the master cylinder M / C via the input rod 1. In addition, it is good also as a structure provided with the booster which boosts the input of the input rod 1. FIG.

  Master cylinder M / C and the suction side of pumps PP and PS (hereinafter referred to as pump P) are connected by conduits (first passages) 11P and 11S (hereinafter referred to as conduit 11). On each pipeline 11, gate-in valves 2P and 2S, which are normally closed solenoid valves, are provided. A pressure sensor PMC that detects the pressure of the master cylinder M / C is provided between the master cylinder M / C and the gate-in valve 2P.

  Also, check valves 6P and 6S (hereinafter referred to as check valves 6) are provided on the pipeline 11 between the gate-in valves 2P and 2S (hereinafter referred to as gate-in valves 2) and the pump P. The check valve 6 allows the brake fluid to flow in the direction from the gate-in valve 2 to the pump P, and prohibits the flow in the opposite direction.

  The discharge side of each pump P and each wheel cylinder W / C are connected by pipes 12P and 12S (hereinafter, pipe 12). On each pipe 12, solenoid-in valves 4FL, 4RR, 4FR, 4RL (hereinafter, solenoid-in valves 4), which are normally open solenoid valves corresponding to the respective wheel cylinders W / C, are provided.

  Also, check valves 7P and 7S (hereinafter referred to as check valves 7) are provided on the pipes 12 and between the solenoid-in valves 4 and the pumps P. The check valves 7 are connected to the pumps P. The brake fluid is allowed to flow in the direction from the valve to the solenoid-in valve 4, and the flow in the opposite direction is prohibited.

  Furthermore, each pipeline 12 is provided with pipelines 17FL, 17RR, 17FR, 17RL (hereinafter referred to as pipeline 17) that bypass each solenoid-in valve 4. The pipeline 17 includes check valves 10FL, 10RR, 10FR, 10RL (hereinafter, check valve 10) is provided. Each check valve 10 allows the flow of brake fluid in the direction from the wheel cylinder W / C toward the pump P, and prohibits the flow in the opposite direction.

  The master cylinder M / C and the pipe line 12 are connected by pipe lines (second passages) 13P and 13S (hereinafter referred to as a pipe line 13). The pipe line 12 and the pipe line 13 are connected to the pump P and the solenoid-in valve 4. Join together. On each pipeline 13, gate-out valves 3P and 3S (hereinafter referred to as gate-out valves 3), which are normally open solenoid valves, are provided. Here, in the pipeline 13, the pipeline on the master cylinder side from the gate-out valve 3 is referred to as a master side pipeline 13a, and the pipeline on the wheel cylinder side is referred to as a foil side pipeline 13b.

  Each pipe line 13 is provided with pipe lines 18P and 18S (hereinafter referred to as pipe lines 18) that bypass each gate-out valve 3. The pipe line 18 includes check valves 9P and 9S (hereinafter referred to as check valves 9). ) Is provided. Each check valve 9 permits the flow of brake fluid in the direction from the master cylinder M / C side toward the wheel cylinder W / C, and prohibits the flow in the opposite direction.

  Reservoirs 16P and 16S (hereinafter referred to as reservoir 16) are provided on the suction side of the pump P, and the reservoir 16 and the pump P are connected by pipe lines 15P and 15S (hereinafter referred to as pipe line 15). Check valves 8P and 8S (hereinafter referred to as check valves 8) are provided between the reservoir 16 and the pump P, and each check valve 8 allows a flow of brake fluid in the direction from the reservoir 16 to the pump P. , Prohibit flow in the opposite direction.

  The wheel cylinder W / C and the pipeline 15 are connected by pipelines 14P and 14S (hereinafter, pipeline 14), and the pipeline 14 and the pipeline 15 merge between the check valve 8 and the reservoir 16. Each pipeline 14 is provided with solenoid-out valves 5FL, 5RR, 5FR, and 5RL, which are normally closed solenoid valves.

  The control unit CU controls the anti-skid brake control (ABS) and vehicle behavior stabilization control (VDC) based on the master cylinder pressure Pmc detected by the pressure sensor PMC and various vehicle information (wheel speed, vehicle acceleration). The values are calculated and the operation of the gate-in valve 2, the gate-out valve 3, the solenoid-in valve 4, the solenoid-out valve 5 and the motor M is controlled.

FIG. 2 is a motor drive circuit diagram of the first embodiment.
The motor upstream circuit 21 connected to one end of the motor M is connected to the battery BAT of the vehicle via a field effect transistor (hereinafter referred to as MOSFET) using an N-channel MOSFET, and the motor connected to the other end of the motor M. The downstream circuit 22 is connected to the ground GND. A gate drive circuit 23 is connected to the gate G of the MOSFET, and a gate voltage (gate signal) from the motor drive unit 24 is input.

  The motor drive unit 24 outputs a gate voltage to the MOSFET according to the drive duty ratio of the motor M generated by the control unit CU. A gate resistor R6 is connected to the gate drive circuit 23 in series for the purpose of preventing parasitic vibration, protecting the gate surge, suppressing switching speed, and the like.

  Between the gate drive circuit 23 and the motor upstream circuit 21, a gate-source resistor R5 and a gate-source protection Zener diode D1 are provided. The gate-source resistor R5 is for extracting the gate-source charge when the MOSFET is OFF. The gate-source protection Zener diode D1 is for maintaining the gate-source voltage within a predetermined range (within an allowable range).

  A voltage monitor circuit 25 is connected to the motor upstream circuit 21, and the voltage across the terminals of the motor M is monitored by a voltage sensor (voltage monitor means) 26. The voltage sensor 26 sends the detected inter-terminal voltage to the control unit CU.

Two damping resistors R1, R3 are connected in series to the voltage monitor circuit 25. These damping resistors R1 and R3 are for attenuating the noise of the signal input to the voltage sensor 26. Further, the voltage monitor circuit 25, a pull-down resistor R2 and a pull-up resistor R4 for circuit stability, the power clamp diode D2 and the ground clamp diode D 3 for circuit protection are connected.

[Motor abnormality judgment processing]
FIG. 3 is a flowchart showing the flow of the motor abnormality determination process executed by the control unit CU of the first embodiment, and each step will be described below. This process is executed when the motor M is not operating.

  In step S1, the motor operation history after the ignition switch is turned on is confirmed. If there is no history, the process proceeds to step S2, and if there is a history, the process proceeds to step S6. The control unit CU stores an operation history of the motor M after the ignition switch is turned on (corresponding to an operation history storage means).

  In step S2, a motor abnormality determination is performed. If it is determined that there is an abnormality, the process proceeds to step S3, and if it is determined to be normal, the process proceeds to a return (corresponding to the first motor determination means). In the motor abnormality determination, the voltage value detected by the voltage sensor 26 is compared with a predetermined threshold A, and when the state where the detected value exceeds the threshold continues for a predetermined time T1, it is determined as abnormal, otherwise Is considered normal.

  Here, the threshold value A is a value that allows the motor M to be determined to be abnormal even when variations (errors) of the sensor signals are taken into consideration. The predetermined time T1 is a determination time for preventing erroneous determination due to sensor noise or the like and improving determination accuracy.

  In step S3, the motor M is forcedly operated for a predetermined time T2, and the process proceeds to step S4 (corresponding to motor energizing means). Here, when the copper oxide film (cuprous oxide film) is adhered between the brush of the motor M and the commutator, the predetermined time T2 is a time that can be sufficiently removed.

  In step S4, a final motor abnormality determination is performed. If it is determined that there is an abnormality, the process proceeds to step S5, and if it is determined that it is normal, the process proceeds to a return (corresponding to the second motor determination means). In the motor abnormality determination, the voltage value detected by the voltage sensor 26 is compared with a predetermined threshold A, the time when the detected value exceeds the threshold is measured by the abnormality counter, and the abnormality counter is a value corresponding to the predetermined time T3. When it becomes, it judges that it is abnormal, and judges otherwise that it is normal. Here, the predetermined time T3 is a determination time for preventing erroneous determination due to sensor noise or the like and improving determination accuracy. The predetermined time T3 may be the same length as the predetermined time T1.

  In step S5, it is determined that the motor M is abnormal, an abnormality flag is set, and the process proceeds to return. When the abnormality flag is set, the control unit CU prohibits the ABS control and the VDC control from operating, and notifies the driver of the abnormality of the brake device using an alarm or a warning light (not shown).

  In step S6, a motor abnormality determination is performed. If an abnormality is determined, the process proceeds to step S7, and if normal is determined, the process proceeds to return (corresponding to a motor abnormality determination means). In the motor abnormality determination, the voltage value detected by the voltage sensor 26 is compared with a predetermined threshold A, the time when the detected value exceeds the threshold is measured by the abnormality counter, and the abnormality counter is a value corresponding to the predetermined time T4. When it becomes, it judges that it is abnormal, and judges otherwise that it is normal. Here, the predetermined time T4 is a determination time for preventing erroneous determination due to sensor noise or the like and improving determination accuracy.

  In step S7, it is determined that the motor M is abnormal, an abnormality flag is set, and the routine proceeds to return.

Next, the operation will be described.
[Prevention of abnormal misjudgment by copper oxide film]
In general, a DC brush motor is generally used as a motor for driving a pump of a vehicle brake device in view of required functions and cost. In this DC brush motor, it is known that a copper oxide film is formed between the brush and the commutator. Copper oxide is an oxide film of chocolate which is generated commutator surface when the motor of the brush is slid, temperature, humidity, current, brush material, the oxide skin film due atmospheric conditions are different.

The copper oxide in the case since simply be removed easy by the current and the sliding of the brush during motor driving, but not functional impact of the motor, which continues a state in which no driving long motor, motor by copper oxide The resistance value between the terminals may increase.

  For this reason, if a motor abnormality is determined based on the voltage between the motor terminals when the motor is not driven, a temporary increase in the resistance value of the motor due to the copper oxide film is erroneously determined as a motor abnormality, and the motor drive Is prohibited. As a result, brake control that requires motor drive, such as ABS control and VDC control, becomes impossible.

  On the other hand, in Example 1, when the state in which the voltage between the terminals of the motor M exceeds the threshold value A continues for a predetermined time T1 when the motor is not driven, a copper oxide film adheres between the brush and the commutator. Therefore, the motor M is forcibly driven. Thereafter, the inter-terminal voltage and the threshold A are compared again, and it is determined that the motor M is abnormal only when the time during which the inter-terminal voltage exceeds the threshold A continues for a predetermined time T3, and otherwise it is determined to be normal.

  In other words, since it is possible to prevent erroneous determination of motor abnormality due to the copper oxide film, it is possible to prevent failure of brake control that requires motor driving such as ABS control and VDC control, and to further improve vehicle safety. .

FIG. 4 is a time chart showing the motor abnormality determination operation of the first embodiment, and shows a case where a copper oxide film is adhered between the brush and the commutator.
At time t1, the voltage between the motor terminals exceeds the threshold A. At time t2, since the time when the voltage between the motor terminals exceeds the threshold A has continued for a predetermined time T1, it is determined that there is an abnormality, the motor M is driven for a predetermined time T2, and the copper oxide film adhered between the brush and the commutator is removed. Remove (Step S1 → Step S2 → Step S3).

  At time t3, motor abnormality final determination is started in step S4. At time t4, the motor terminal voltage is equal to or lower than the threshold value A, so that the motor M is determined to be normal. For this reason, it is possible to prevent erroneous determination of motor abnormality due to adhesion of the copper oxide film.

  On the other hand, FIG. 5 shows a case where the coil of the motor M is disconnected, and is the same as FIG. 4 until time t3. However, at time t5, the voltage between the motor terminals is a threshold value in the final determination of the motor abnormality in step S4. Since the time exceeding A has continued for a predetermined time T3, the motor M is determined to be abnormal, an abnormality flag is set, the driving of the motor M is prohibited, and the abnormality is notified to the driver.

  FIG. 6 shows a case where an abnormality has occurred in the motor M after the motor M is driven after the ignition switch is turned on. Since the motor operation history is stored by the control unit CU at the time t10, the step S1 is performed at the time t11. In step S6, it is determined that there is a motor operation history and motor abnormality determination is started. That is, when the motor M is driven after the ignition switch is turned on, the copper oxide film has already been removed. In this case, the abnormality is determined without driving the motor.

  At time t12, the time during which the voltage between the motor terminals exceeds the threshold value A continues for a predetermined time T4. Therefore, the motor M is determined to be abnormal and an abnormality flag is set, and the motor M is prohibited from being driven and abnormal to the driver. Inform.

Next, the effect will be described.
The brake device according to the first embodiment has the following effects.
(1) A brake device having a brush motor M for driving a pump, which is detected by a voltage sensor 26 that detects a voltage between terminals of the motor M when the motor M is not energized (non-driven). First motor determining means (step S2) for determining that a copper oxide film is adhered between the brush of the motor M and the commutator when the voltage value exceeds a predetermined threshold A set in advance; Prepared. Thereby, it is possible to prevent erroneous determination of motor abnormality due to the copper oxide film.

  (2) When it is determined by the first motor determining means (step S2) that the copper oxide film is attached, the motor energizing means (step S3) for energizing the motor M for a predetermined time T2 and the motor M by the motor energizing means A second motor determination means (step S4) for determining that the copper oxide film has been removed and canceling the determination of the abnormal state when the voltage value detected by the voltage sensor 26 after energization of the voltage becomes equal to or less than the threshold value A; Equipped with. Thereby, the abnormality determination of the motor M can be reliably performed even when the motor is not driven.

(3) The operation history storage means for storing the operation history of the motor M after the ignition switch is turned on, and when the operation history is stored by the operation history storage means, the first motor determination means (step S2) uses the copper oxide Motor abnormality determining means (step S6) for determining that the motor M is abnormal without energizing the motor M for a predetermined time even when it is determined that the film is attached. Thereby, abnormality determination can be performed without energizing the motor M, and the responsiveness of abnormality determination can be improved.

1 is a hydraulic circuit diagram of a brake device according to a first embodiment. FIG. 3 is a motor drive circuit diagram of the first embodiment. It is a flowchart which shows the flow of the motor abnormality determination process performed with the control unit CU of Example 1. FIG. 2 is a time chart showing a motor abnormality determining action when the copper oxide film of Example 1 is attached. 3 is a time chart showing a motor abnormality determination operation when the motor coil is disconnected (when there is no operation history) according to the first embodiment. 3 is a time chart showing a motor abnormality determination operation when the motor coil is disconnected (when there is an operation history) according to the first embodiment.

Explanation of symbols

M Electric motor (brush motor)
P pump 26 voltage sensor (voltage monitoring means)

Claims (2)

A brake device having a brush motor for driving a pump,
Voltage monitoring means for detecting a voltage between terminals of the motor when the motor is not energized;
First motor determination means for determining that the motor is in an abnormal state when the voltage value detected by the voltage monitoring means exceeds a predetermined threshold value set in advance;
A motor energizing unit configured to energize the motor for a predetermined time to drive the motor when the first motor determining unit determines an abnormal state;
An operation history storage means for storing an operation history of the motor after the ignition switch is turned on;
When the operation history is stored by the operation history storage means, it is determined that the motor is abnormal without energizing the motor for a predetermined time even when it is determined that the first motor determination means is in an abnormal state. Motor abnormality determination means;
A brake device comprising: The brake device according to claim 1, wherein
And a second motor determination unit that cancels the determination of the abnormal state when the voltage value detected by the voltage monitoring unit is less than or equal to the threshold value after the motor energization unit energizes the motor. Brake device to play.

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