JP2006160204A - Electric parking brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To minimize the number of operations of an electric parking brake. <P>SOLUTION: The electric parking brake is operated by an electric motor 26. An ignition switch SW1 detects whether an ignition key is at an on/off position. A shift lever switch SW3 detects whether a shift lever is in a parking range or not. A seat belt buckle switch SW4 detects whether a seat belt buckle is mounted or not. A judging part 74 gives commands to a motor driving part 76 to apply the parking brake when signals from the switches SW1 and SW3 satisfy predetermined operation conditions. The judging part 74 does not apply the parking brake in a state that a seat belt is mounted even when the operation conditions are satisfied. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric parking brake device, and more particularly to an electric parking brake device that minimizes the operation of an electric parking brake.

  In general, a vehicle such as an automobile is equipped with a parking brake in addition to a hydraulic brake that generates a braking force by hydraulic pressure, such as a foot brake. The simplest type of parking brake is to drive a wire by pulling an operation lever to operate a brake pad and brake a wheel. However, in recent years, an electric parking brake (EPB) device that is operated or released by switching of an operation switch or the like by a driver has also been adopted. In this electric parking brake device, when the driver sets the operation switch to the operating side, the electric motor is driven and the wire is caught to operate the parking brake, and when the operation switch is set to the releasing side, the wire is rewound. The parking brake is released (see, for example, Patent Document 1).

  Such an electric parking brake device facilitates the operation of the parking brake and enables operation control of the parking brake. For example, it is possible to execute smooth and easy automatic start control using a parking brake when starting on a slope, or to perform automatic on / off control of the parking brake. Moreover, in the electric parking brake device, since the braking force can be controlled relatively easily by the motor control, for example, it is also considered to use it as a braking means for a running vehicle as a backup of a hydraulic brake.

Further, when it is not preferable to operate the parking brake, a control for prohibiting the operation has been devised. For example, Patent Document 1 discloses an electric parking brake device that presumes that the parking brake cannot be properly released due to freezing when the outside air temperature is low, and prohibits the operation process of the parking brake. ing.
JP 2001-106059 A

  However, in Patent Document 1, whether or not the parking brake can be operated is determined by referring only to the outside air temperature. Therefore, the parking brake is always operated except in a cold region, and the operation frequency of the parking brake is not necessarily reduced. In addition, in an automatic vehicle, it is possible to keep the vehicle stopped only by putting the shift lever into the parking range without operating the parking brake. Therefore, if the vehicle is not specifically instructed or operated, the vehicle stops. The parking brake does not need to be activated unless it is difficult to maintain.

  This invention is made | formed in view of such a condition, The objective is to provide the technique which controls the frequency | count of operation of an electric parking brake to the minimum necessary.

  One embodiment of the present invention relates to an electric parking brake device. This device has a parking brake operated by an actuator, a driving means for sending a driving signal to the actuator, an ignition detecting means for detecting that an ignition key is in an off position, and a shift lever in the parking range. Shift detecting means for detecting the ignition means, and determining means for instructing the driving means to operate a parking brake when detection signals from the ignition detecting means and the shift detecting means satisfy a predetermined operating condition, It is characterized by providing.

  According to this aspect, since the necessity of the parking brake is determined based on the ignition switch and the position information of the shift lever, the operation of the parking brake device, which is not necessarily required, is eliminated, and the service life of the parking brake device can be extended. it can. In addition, since the unnecessary parking brake is not activated, it is possible to prevent the occurrence of malfunction due to the freezing of the wire when the outside air temperature is low.

  The electric parking brake device may further include a seat belt detection means for detecting that the seat belt is worn, and in this case, the determination means may be a seat even when the operating condition is satisfied. The parking brake may not be operated in a state where the belt is attached.

  As a result, the seatbelt is removed and the parking brake device is activated after the driver confirms his intention to leave the vehicle, so the shift lever is not placed in the parking range after the vehicle stops and the electric parking brake is activated. When the shift lever is moved to the parking range later, there is no need to perform an operation for releasing the electric parking brake, so that the number of actuations of the electric parking brake can be further reduced.

  The electric parking brake device may further include an inclination angle detection unit that detects an inclination angle of the vehicle. In this case, the determination unit provides the driving unit with the detected inclination angle when the detected inclination angle is equal to or larger than a preset value. The parking brake may be instructed to operate. As a result, at an inclination angle (for example, 5 degrees) at which the vehicle cannot be held without operation of the parking brake, the parking brake is operated even if the shift lever is in the parking range. Can be held in.

  According to the electric parking brake device of the present invention, since the number of actuations of the electric parking brake is controlled to be a necessary minimum, the service life of the electric parking brake device can be extended.

  FIG. 1 is a configuration diagram of a brake system 10 including an electric parking brake device according to an embodiment of the present invention. The brake system 10 includes a hydraulic brake 12 that decelerates and stops when the vehicle travels (not shown), and an electric parking brake (hereinafter also referred to as “EPB”) 14 that mainly maintains the stopped state of the vehicle. The

  The hydraulic brake 12 has a known configuration using, for example, a vacuum booster. When the driver depresses the brake pedal 16, hydraulic pressure is generated by the master cylinder 18. The generated hydraulic pressure passes through the brake pipe 20 and is transmitted to a cylinder of a front wheel brake device 22 that is, for example, a disc brake provided on a front wheel of a vehicle (not shown). As a result, the brake pad is pressed against the disc and the braking force is exerted. An anti-lock brake system (hereinafter referred to as “ABS”) 24 is interposed in the route of the brake pipe 20, and each front wheel brake device 22 has an optimal braking state based on the running state of the vehicle, the road surface condition, and the like. The braking force, the braking timing, and the like are controlled so as to be realized.

  On the other hand, the electric parking brake 14 includes a hoisting device 28 driven by an electric motor 26. The hoisting device 28 is configured to wind or unwind the wire 30. A lock piece 32 that engages with the lock pin 40 of the lock mechanism is fixed to the tip of the wire 30. A wire 31 is further fixed to the tip of the lock piece 32, and the tip of the wire 31 is connected to, for example, a rear wheel brake device 34 provided on the rear wheel of the vehicle. The rear wheel brake device 34 is, for example, a drum brake. When the hoisting device 28 is driven to wind the wire 30, the wire 31 is also hoisted with it, and the rear wheel brake device 34 is operated to generate a braking force on the rear wheel.

  In order to maintain the state of the wire 30 wound up by the hoisting device 28 even after the operation of the electric motor 26 is stopped, that is, the braking state of the rear wheel brake device 34 after the wire 30 is stopped in the wound state is maintained. Therefore, the electric parking brake 14 has a lock mechanism including the lock piece 32 and the lock pin 40. A sawtooth-shaped inclined surface 32 a is formed on one surface of the lock piece 32, and a lock pin 40 having an inclined surface 40 a that engages with the inclined surface 32 a is disposed to face the one surface of the lock piece 32. At the time of winding the wire, the lock piece 32 is pulled upward in FIG. And the lock pin 40 are engaged. For this reason, even if the electric motor 26 is not operated, the electric parking brake 14 is not released.

  The lock pin 40 is always biased in a direction to engage with the lock piece 32 by a biasing means such as a spring (not shown). The other end of the lock pin 40 is configured as a piston of the cylinder 42. The cylinder 42 is provided with a pressure chamber 42 a so that brake hydraulic oil can enter and exit through a pipe 44. When the driver steps on the brake pedal 16, brake hydraulic oil is supplied from the master cylinder 18 to the pressure chamber 42 a of the cylinder 42 via the brake pipe 20 and the pipe 44. When this pressure exceeds the urging force of the urging means, the lock pin 40 moves away from the lock piece 32 and the lock mechanism is released. In this state, when the hoisting device 28 is driven in the reverse rotation direction and the wire 30 is rewound, the rear wheel brake device 34 is released to enter the non-braking state.

  The ECU 36 rotates the electric motor 26 in the normal direction or the reverse direction according to the on / off state of various switches 38 described later. The G sensor 48 is provided in a vehicle body (not shown), detects acceleration in the front-rear direction and the left-right direction of the vehicle, and transmits the detected acceleration to the ECU 36.

  FIG. 2 is a functional block diagram for explaining the operation of the ECU 36 and various switches 38. The ECU 36 includes a switch detection unit 72, a determination unit 74, and a motor drive unit 76. Each block in FIG. 2 can be realized in hardware by elements and circuits such as a CPU and memory of a computer, and is realized in software by a computer program or the like. It is drawn as a functional block. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by a combination of hardware and software.

  The ignition switch SW1 is turned off when the ignition key is set to the off position, and is turned on when the ignition key is in any other position. The control mode switch SW2 is disposed in the vicinity of a panel on the front surface of the driver's seat or a shift lever in a vehicle cabin (not shown). The driver can select or cancel the automatic control mode of the electric parking brake by the control mode switch SW2. The shift lever switch SW3 is turned on when the shift lever is in the parking range, and is turned off when in the other range. The seat belt buckle switch SW4 is turned on when the seat belt buckle is attached and turned off when the seat belt buckle is removed.

  The switch detection unit 72 in the ECU 36 detects the on / off state of the switches SW <b> 1 to SW <b> 4 and sends the detection result to the determination unit 74. The determination unit 74 operates the electric parking brake 14 based on the on / off states of SW1 to SW4 received from the switch detection unit 72 and the G values in the vehicle front-rear direction and the left-right direction obtained from the G sensor 48. Commands the motor drive 76. When the motor drive unit 76 receives an operation command from the determination unit 74, the motor drive unit 76 operates the electric motor 26 of FIG. 1 to drive the hoisting device 28 in the winding direction.

Next, the operation of the determination unit 74 will be described with reference to the flowchart of FIG. Note that the process shown in FIG. 3 is repeatedly executed at regular intervals regardless of whether the vehicle is running or stopped.
First, it is determined whether or not the ignition switch SW1 is on (S10). If SW1 is off (N in S10), it is determined whether or not the control mode switch SW2 is on (S12). If the ignition switch SW1 is on (Y in S10) or the control mode switch SW2 is off (N in S12), the current routine is terminated. If the control mode switch SW2 is on in S12 (Y in S12), it is determined based on the switch SW3 whether or not the shift lever is in the parking range (P range) (S14). If it is not in the parking range (N in S14), it is determined based on the switch SW4 whether or not the seat belt buckle is worn (S18). If the seat belt buckle is not worn (N in S18), it is determined that the occupant has got off, and the determination unit 74 activates the electric parking brake (S20). If the seat belt buckle is attached (Y in S18), this routine is terminated. The determination of S18 is to avoid the operation of releasing the parking brake when the shift lever is moved to the parking range after the electric parking brake is turned on because the shift lever is not in the parking range. This is because the parking brake is activated after confirming that the driver has got off the vehicle.

  If it is determined in S14 that the shift lever is in the parking range (Y in S14), then the determination unit 74 determines whether or not the vehicle is stopped on an inclined ground (S16). In this embodiment, this determination is performed using the G sensor 48. The output of the G sensor arranged to detect the acceleration in the front-rear direction and the left-right direction of the vehicle is 0 in both the front-rear direction and the left-right direction when the vehicle is stopped on a horizontal plane. If the vehicle stops at the slope value, some value is detected in that direction. Therefore, an inclination angle (for example, 5 degrees) at which the vehicle cannot be stopped without the parking brake being actuated is obtained in advance by experiments and the corresponding output value of the G sensor is stored. If the output of the G sensor is equal to or greater than the threshold value (Y in S16), the parking brake should be operated even if the shift lever is in the parking range, so the determination of S18 is subsequently executed. If it is not less than the threshold value (N in S16), it is not necessary to operate the parking brake, and this routine is terminated.

  As explained above, according to this flowchart, only when the ignition key is in the off position, the control mode is on, the shift lever is not in the parking range, and the seat belt buckle is removed and the passenger gets off. The electric parking brake is activated. Further, even when the shift lever is not in the parking range, the electric parking brake is activated when the vehicle is stopped on the slope. In other states, for example, when the shift lever is in the parking range and the vehicle is not parked on a sloping ground, it is possible to hold the vehicle sufficiently with just the resistance of the engine without operating the electric parking brake. Do not activate the parking brake. Further, the electric parking brake is not operated even when the seat belt is not removed and the driver is not getting off the vehicle. As described above, in the present embodiment, control is performed so as to minimize the conditions for operating the electric parking brake. Therefore, the number of operation times of the electric parking brake is reduced, so that the service life of the electric parking brake device can be extended. In addition, since the unnecessary parking brake is not activated, it is possible to prevent the occurrence of malfunction due to the freezing of the wire when the outside air temperature is low.

  The present invention has been described above based on the embodiment. It should be understood by those skilled in the art that these embodiments are exemplifications, and that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention.

  In the embodiment, the on / off state is determined in the order of the ignition switch SW1, the control mode switch SW2, the shift lever switch SW3, and the seat belt buckle switch SW4. However, the order of these determinations may be different.

It is a lineblock diagram of the brake system provided with the electric parking brake concerning one embodiment of the present invention. It is a functional block diagram explaining operation | movement of ECU and various switches. It is a flowchart explaining operation | movement of the determination part.

Explanation of symbols

  SW1 ignition switch, SW2 control mode switch, SW3 shift lever switch, SW4 seat belt buckle switch, 10 brake system, 12 hydraulic brake, 14 electric parking brake, 16 brake pedal, 18 master cylinder, 20 brake pipe, 22 front wheel brake device, 24 ABS, 26 Electric motor, 28 Hoisting device, 30 Wire, 31 Wire, 32 Lock piece, 34 Rear wheel brake device, 36 ECU, 38 Various switches, 40 Lock pin, 42 Cylinder, 48 G sensor, 72 Switch detector 74 determination part, 76 motor drive part.

Claims (3)

A parking brake actuated by an actuator;
Drive means for sending a drive signal to the actuator;
Ignition detection means for detecting that the ignition key is in the off position;
Shift detection means for detecting that the shift lever is in the parking range;
Determining means for instructing the driving means to operate a parking brake when detection signals from the ignition detecting means and the shift detecting means satisfy a predetermined operating condition;
An electric parking brake device comprising: A seat belt detecting means for detecting that the seat belt is worn;
2. The electric parking brake device according to claim 1, wherein the determination unit does not operate the parking brake in a state where a seat belt is worn even when the operation condition is satisfied. 3. An inclination angle detecting means for detecting an inclination angle of the vehicle;
3. The electric parking brake according to claim 1, wherein the determination unit instructs the driving unit to activate a parking brake when the detected inclination angle is equal to or greater than a preset value. 4. apparatus.

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