JP2008174101A - Electric parking brake device for vehicle, and method for detecting abnormality of electric parking brake device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric parking brake device for a vehicle and its abnormality detecting method for appropriately detecting an abnormality of cable breakage. <P>SOLUTION: The electric parking brake device mounted to the vehicle comprises a computing means for computing a target braking force corresponding to a slope gradient in the present position of one's own vehicle; a tension generating means for generating cable tension for generating the target braking force to a parking brake cable; a determining means for determining whether the own vehicle is moving; and a cable abnormality detecting means for detecting the abnormality of the parking brake cable. If the own vehicle is moving when generating first cable tension for generating the target braking force, the tension generating means generates second cable tension which is double the first cable tension. The cable abnormality detecting means determines that an abnormality has occurred at the parking brake cable if the own vehicle is not moving when the tension generating means has generated the second cable tension. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention generally relates to an electric parking brake (parking brake) device mounted on a vehicle, and more particularly to an electric parking brake device for a vehicle that appropriately detects a cable disconnection abnormality and a method for detecting the abnormality.

  Conventionally, an electric parking brake device for vehicles is known (for example, refer to patent documents 1).

Patent Document 1 includes an equalizer mechanism (C) that evenly distributes a linear driving force obtained by decelerating and converting a rotational driving force, which is an output of an electric motor (11), to two cables (17, 19). An electric parking brake device is disclosed.
JP-A-2005-016600

  In the configuration and structure of the conventional device described in Patent Document 1, in order to detect disconnection abnormality of the parking brake cable connecting the equalizer and the parking brake, a tension sensor is provided in each of these two parking brake cables. Can be considered.

  Here, it is conceivable that the tension sensor is provided in only one of the two parking brake cables to reduce cost, weight, and physique (mounting space).

  This is because when the parking brake cable on the side where the tension sensor is not provided is suddenly disconnected, the tension of the cable becomes 0, the equalizer is inclined, and the tension on the parking brake cable on the side where the tension sensor is provided. Therefore, it is based on the insight that a cable disconnection abnormality on the side where no tension sensor is provided can be detected by one tension sensor.

  However, when the tension sensor is provided only on one cable as described above, if the cable disconnection on the side where the tension sensor is not provided progresses gradually, the amount of change in tension is too small and the cable disconnection occurs. May not be detected. Further, when repairing a service or the like, forgetting to restore the cable (toggle off), it becomes impossible to detect a cable break.

  The present invention is for solving such a problem, and for a vehicle that appropriately detects a cable disconnection abnormality while adopting a structure in which a tension sensor is provided on only one of two parking brake cables. An object of the present invention is to provide an electric parking brake device and an abnormality detection method thereof.

  A first aspect of the present invention for achieving the above object is an electric parking brake device mounted on a vehicle, which detects or acquires a slope of the current position of the host vehicle, and A calculation unit that calculates a target braking force for stopping the host vehicle, a tension generation unit that generates a cable tension that generates the target braking force calculated by the calculation unit in the parking brake cable, and the host vehicle moves. Determination means for determining whether or not the parking brake cable is abnormal, and cable abnormality detection means for detecting abnormality of the parking brake cable, wherein the tension generation means generates a first braking force calculated by the calculation means. When the determination means determines that the host vehicle is moving when cable tension is generated in the parking brake cable A second cable tension that is twice as much as the first cable tension is generated in the parking brake cable, and the cable abnormality detecting means is configured such that the tension generating means applies the second cable tension to the parking brake cable. When it is determined that the vehicle is not moving by the determination means, the vehicle parking brake device determines that an abnormality has occurred in the parking brake cable.

  According to the first aspect, when a cable disconnection abnormality is detected in any one of the two parking brake cables, if a double tension is generated in the other parking brake cable, the corresponding wheel If the vehicle is moving despite the fact that the parking brake is pulled with the target tension, the target tension is By observing whether or not the movement of the vehicle stops by doubling the initial value, it is possible to determine whether or not a cable disconnection abnormality has occurred in any one of the parking brake cables.

  Note that in the first aspect, the vehicle electric parking brake device is further provided on any one of the parking brake cables, and detects the tension of the cable generated in the one parking brake cable. And the cable abnormality detecting means outputs the first cable tension when the tension generating means generates the first cable tension in the parking brake cable. If it is less, it is possible to determine that an abnormality has occurred in the one parking brake cable provided with the tension detecting means, which is more preferable.

  A second aspect of the present invention for achieving the above object is an abnormality detection method in an electric parking brake device mounted on a vehicle, which detects or acquires a slope of the current vehicle position, When it is determined that the host vehicle is moving when the first cable tension that generates the target braking force for stopping the host vehicle on the slope of the slope is generated in the parking brake cable, If the second cable tension, which is twice the cable tension of the vehicle, is generated in the parking brake cable, and it is determined that the movement of the host vehicle has stopped, an abnormality has occurred in the parking brake cable. This is an abnormality detection method for an electric parking brake device for a vehicle.

  According to the second aspect, when a cable disconnection abnormality is detected in any one of the two parking brake cables, if a double tension is generated in the other parking brake cable, the corresponding wheel If the vehicle is moving despite the fact that the parking brake is pulled with the target tension, the target tension is By observing whether or not the movement of the vehicle stops by doubling the initial value, it is possible to determine whether or not a cable disconnection abnormality has occurred in any one of the parking brake cables.

  In the second aspect, when the first cable tension is generated in the parking brake cable, the cable tension of any one of the parking brake cables is detected, and the detected cable tension is When the tension is less than the first cable tension, it is preferable to determine that an abnormality has occurred in the one parking brake cable.

  ADVANTAGE OF THE INVENTION According to this invention, the electric parking brake apparatus for vehicles which detects a cable disconnection abnormality appropriately, and its abnormality detection method can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. Note that the basic concept, main hardware configuration, operating principle, basic control method, and the like of the electric parking brake device for a vehicle itself are known to those skilled in the art, and thus detailed description thereof is omitted.

  Hereinafter, an electric parking brake device for a vehicle and an abnormality detection method thereof according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic configuration diagram of an electric parking brake device 100 for a vehicle according to the present embodiment.

  The vehicle electric parking brake device 100 includes an actuator 101 and a control unit 102 that performs operation control of the actuator 101 and various arithmetic processes as described later.

  The control unit 102 is, for example, an ECU (Electronic Control Unit).

  In addition, the control unit 102 appropriately transmits road surface gradient information and wheel speed information. The control unit 102 controls the actuator 101 so that the cable tension suitable for the road surface gradient at that time is realized when the electric parking brake is operated.

  Here, the road surface gradient information may be detected by, for example, a front-rear G sensor that detects acceleration in the vehicle front-rear direction, which is known to those skilled in the art, or, for example, GPS ( It may be extracted by illuminating the current position of the host vehicle detected by a Global Positioning System (Global Positioning System) or the like. The wheel speed information is detected by, for example, a wheel speed sensor known to those skilled in the art.

  The electric parking brake device 100 is activated by a predetermined operation of the driver (for example, pressing a predetermined button) when the manual mode is set, and is stopped for a long time, for example, when the auto mode is set. Triggered when a situation occurs, such as seat belt removal, driver's seat door open, engine hood open, luggage door open, hydraulic brake system failure.

  The actuator 101 includes an electric motor 103 that rotates according to a command from the control unit 102 and generates a torque for pulling / releasing parking brake cables 107 and 108 described later. As long as such a function is realized, the electric motor 103 may be any type of motor.

  The actuator 101 further includes a gear / clutch mechanism 104 that transmits the rotation of the electric motor 103 to a shaft 105 to be described later and holds the cable tension at that time when the electric motor 103 is stopped. The gear / clutch mechanism 104 has, for example, a spring type clutch as a configuration for maintaining the cable tension.

  Actuator 101 further includes a threaded shaft 105 and an equalizer 106 disposed on shaft 105.

  The rotation of the electric motor 103 is transmitted to the shaft 105 via the chia / clutch mechanism 104. The shaft 105 passes through the equalizer 106 and is screwed with a female screw cut in the equalizer 106.

  As described above, when the electric motor 103 rotates and thus the shaft 105 rotates, the equalizer 106 reciprocates on the shaft 106 in accordance with the rotation direction.

  The equalizer 106 is connected to the vehicle body side ends of parking brake cables 107 and 108 whose wheel side ends are connected to parking brakes (usually so-called drum brakes) for the left and right rear wheels. The equalizer 106 has a function of evenly distributing the tension to the left and right parking brake cables 107 and 108.

  In the present embodiment, the tension sensor 109 is provided only on one of the two parking brake cables 107 and 108 (here, the cable 107). The tension sensor 109 detects the tension of the parking brake cable 107 and transmits it to the control unit 102. Various tension sensors that realize such a function have already been proposed and are known to those skilled in the art, and thus detailed description thereof is omitted. In this embodiment, any tension sensor can be employed.

  Next, the flow of the abnormality detection determination process performed by the vehicle electric parking brake device 100 will be described with reference to the flowchart of FIG.

  This flow is started by a predetermined operation (for example, pressing of a manual switch button) by the driver when the electric parking brake device 100 is in the manual operation state, and by turning on the ignition switch when in the automatic operation state.

  When this flow is started, first, the control unit 102 determines whether or not the road surface gradient θ at the current position of the host vehicle is between the lower limit value α and the upper limit value β based on the acquired road surface gradient information. (S201).

  Here, the lower limit value α represents the lower limit value of the gradient at which the vehicle moves due to the road surface gradient unless the parking brake is operated. In other words, when the road surface gradient θ is less than α, the vehicle does not move due to the road surface gradient even if the parking brake is not operated. Therefore, it is not necessary to operate the parking brake, and therefore the parking brake is not operated.

  The upper limit value β represents the upper limit value of the gradient that can stop the movement of the vehicle due to the road gradient when the parking brake is operated. In other words, when the road surface gradient θ is larger than β, it is not necessary to operate the parking brake because the vehicle movement due to the road surface gradient cannot be stopped even if the parking brake is operated, and therefore the parking brake is not operated. .

  When it is determined that the road gradient [theta] is between the lower limit [alpha] and the upper limit [beta] and the parking brake should be activated to stop the movement of the vehicle due to the road gradient ("YES" in S201), then control is performed. As usual, the unit 102 sets the cable tension F for generating a braking force for stopping the vehicle to the parking brake of the rear two wheels according to the magnitude of the road surface gradient θ as a target tension to the electric motor 103. A rotation command is sent (S202).

  Next, the control unit 102 monitors the transmitted wheel speed information to determine whether the wheel speed is greater than 0, that is, whether the host vehicle is moving (S203).

  When the host vehicle is not moving (“NO” in S203), it is determined that no abnormality has occurred in the electric parking brake device 100 (S208).

  On the other hand, when it is determined that the wheel is rotating (“YES” in S203), the control unit 102 confirms the output of the tension sensor 109, and is the tension sensor 109 detecting a tension greater than the target tension F? It is determined whether or not (S204).

  If the tension sensor 109 detects no tension equal to or greater than the tension F (“NO” in S204), the electric motor 103 is driven and controlled so that the tension F is generated in the parking brake cables 107 and 108. Since the parking brake cable 107 does not have a tension equal to or higher than the tension F, it is determined that a cable break abnormality has occurred in the parking brake cable 107 which is the cable on the side where the tension sensor 109 is provided. (S209).

  On the other hand, when the tension sensor 109 detects a tension equal to or higher than the tension F (“YES” in S204), the electric motor 103 is driven and controlled so that the tension F is generated in the parking brake cables 107 and 108, and the parking brake cable Since a tension equal to or greater than the tension F is generated in 107, it is determined that a cable break abnormality has not occurred in the parking brake cable 107, which is a cable on the side where the tension sensor 109 is provided.

Next, the control unit 102 determines whether or not the tension 2F (F × 2) that is twice the initial target tension F is equal to or less than the maximum generated tension F _MAX that can be generated by the actuator 101 (S205).

When the tension 2F that is twice the initial target tension F is equal to or less than the maximum generated tension F _MAX that can be generated by the actuator 101 (“YES” in S205), the control unit 102 newly sets the cable tension 2F to the target tension. Then, a rotation command is sent to the electric motor 103 (S206).

  Next, the control unit 102 monitors the transmitted wheel speed information to determine whether the wheel speed is greater than 0, that is, whether the host vehicle is moving (S207).

  When the host vehicle is not moving ("NO" in S207), the movement of the host vehicle due to the road gradient could be stopped by doubling the cable tension and thus doubling the generated braking force. Therefore, it is determined that the cable break abnormality has occurred in the parking brake cable 108 which is the cable on the side where the tension sensor 109 is not provided (S210).

  On the other hand, when it is determined that the wheel is rotating (“YES” in S207), the control unit 102 causes a cable disconnection abnormality to occur in the parking brake cable 108 that is the cable on which the tension sensor 109 is not provided. Therefore, it is determined that another abnormality has occurred in the actuator 101, and one routine of this flow is terminated (S211).

Similarly, larger than the maximum developed tension _{F MAX} twice the tension 2F of the initial target tension F can actuator 101 to generate ( "NO" in S205), can not perform a S206～S207, i.e., initially Since it is not possible to confirm whether or not the rotation of the wheel is stopped by actually generating a tension 2F that is twice the target tension F of the parking brake cable, the control unit 102 is provided on the side where the tension sensor 109 is not provided. It can not be determined that a cable break abnormality has occurred in the parking brake cable 108, which is a cable, and it is determined that another abnormality has occurred in the actuator 101, and one routine of this flow is terminated ( S211).

  Thus, according to the present embodiment, when a cable disconnection abnormality is detected in any one of the parking brake cables, if a double tension is generated in the other parking brake cable, Based on the insight that twice the braking force is generated and the vehicle can stop moving due to the road gradient, the target tension is set to the initial value when the wheel is rotating despite the parking brake being activated. By observing whether or not the rotation of the wheel is doubled, it is possible to determine whether or not a cable disconnection abnormality has occurred in any one of the parking brake cables. Even if only one of the parking brake cables is provided, it is possible to appropriately detect the cable disconnection abnormality.

  The present invention can be used for an electric parking brake device for vehicles. The power source type, fuel type, appearance design, weight, size, running performance, etc. of the vehicle to be mounted are all unquestioned.

1 is a schematic configuration diagram of an electric parking brake device for a vehicle according to an embodiment of the present invention. It is a flowchart which shows the flow of the abnormality detection determination process by the electric parking brake apparatus for vehicles which concerns on one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Electric parking brake apparatus for vehicles 101 Actuator 102 Control part 103 Electric motor 104 Gear / clutch mechanism 105 Shaft 106 Equalizer 107, 108 Parking brake cable 109 Tension sensor

Claims (4)

An electric parking brake device mounted on a vehicle,
Calculating or calculating a target braking force for detecting or acquiring the slope of the current position of the host vehicle and stopping the host vehicle on the slope of the slope;
A tension generating means for generating a cable tension for generating a target braking force calculated by the calculating means in the parking brake cable;
Determining means for determining whether or not the host vehicle is moving;
Cable abnormality detecting means for detecting abnormality of the parking brake cable,
The tension generating means determines that the host vehicle is moving by the determining means when the first cable tension that generates the target braking force calculated by the calculating means is generated in the parking brake cable. A second cable tension that is twice the tension of the first cable tension is generated in the parking brake cable,
The cable abnormality detection means, when the tension generating means generates the second cable tension to the parking brake cable, and the determination means determines that the host vehicle is not moving, the parking brake An electric parking brake device for a vehicle, characterized in that it is determined that an abnormality has occurred in a cable. The electric parking brake device for a vehicle according to claim 1,
A tension detecting means provided on any one of the parking brake cables, and detecting a cable tension generated in the one parking brake cable;
If the output of the tension detection means is less than the first cable tension when the tension generation means generates the first cable tension in the parking brake cable, the cable abnormality detection means, An electric parking brake device for a vehicle, wherein it is determined that an abnormality has occurred in the one parking brake cable provided with the tension detecting means. An abnormality detection method in an electric parking brake device mounted on a vehicle,
When the parking brake cable generates a first cable tension that detects or acquires the slope of the current position of the vehicle and generates a target braking force for stopping the vehicle on the slope, the vehicle Is determined to be moving, a second cable tension that is twice the first cable tension is generated in the parking brake cable, thereby determining that the vehicle has stopped moving. And determining that an abnormality has occurred in the parking brake cable in the case of an abnormality in the vehicle electric parking brake device. An abnormality detection method for an electric parking brake device for a vehicle according to claim 3,
When the first cable tension is generated in the parking brake cable, the cable tension of one of the parking brake cables is detected, and the detected cable tension is less than the first cable tension. In this case, it is determined that an abnormality has occurred in the one parking brake cable, and the abnormality detection method for the vehicle electric parking brake device is characterized.

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