JP2005313755A - Brake system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake system capable of certainly detecting abnormality of an electric type parking brake. <P>SOLUTION: The brake system has a parking brake electric driving part 34 for operating the parking brake by taking up a cable; a parking brake control part 104 of ECU 20 for controlling the parking brake electric driving part 34; and an abnormality detection part 102 of the ECU 20 for detecting abnormality of the parking brake. Output torque of a motor of the parking brake electric driving part 34 is detected by a torque sensor 39. A rotation speed of a rear wheel applied with braking force of the parking brake is detected by a wheel speed sensor 22. The abnormality detection part 102 detects abnormality of the parking brake based on the detection result of the torque sensor 39 and detection result of the wheel speed sensor 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a brake system including an electric parking brake.

  Conventionally, a parking brake of a type that generates a desired braking force by directly pulling a cable of the parking brake via a lever or a pedal has been widely used. When such a conventional parking brake is used, a vehicle driver or the like can sensuously grasp an abnormality that occurs in the parking brake from an operation amount or operation force of a lever or the like.

  In recent years, in addition to the above-described conventional parking brake, development of an electric parking brake has been promoted. The electric parking brake is excellent in that it can generate a large braking force with a relatively small operating force, but it can be used to sense abnormalities in the parking brake from the amount of operation of the lever and the operating force. Difficult to do.

An electric parking brake device that detects an abnormality occurring in the parking brake based on the relationship between the winding force of the parking brake cable and the winding amount of the cable is known as one that detects an abnormality in the electric parking brake. Patent Document 1).
JP 2001-106060 A

  From the viewpoint of improving safety by operating the electric parking brake in an appropriate state, it is preferable to propose another technique for accurately detecting an abnormality in the electric parking brake.

  In particular, in the electric parking brake device disclosed in the above-mentioned Patent Document 1, it is possible to detect an abnormality related to cable extension or the like, but it is difficult to detect an abnormality occurring in other members of the parking brake. For example, when a disc brake is used as a parking brake, it is difficult to detect an abnormality related to wear or the like of the brake pad in the above-described electric parking brake device.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a brake system that can accurately detect an abnormality of an electric parking brake.

  One aspect of the present invention relates to a brake system. The brake system includes a parking brake having a cable, an electric hoisting unit that operates the parking brake by hoisting the cable, a hoisting control unit that controls the electric hoisting unit, and the hoisting of the cable by the electric hoisting unit. Hoisting force acquisition means for acquiring a force-related amount, speed-related amount acquisition means for acquiring a related amount of the rotational speed of a wheel on which a braking force generated by the parking brake acts, and the hoisting force acquisition means acquired And an abnormality detecting means for detecting an abnormality of the parking brake based on the related amount of the cable winding force and the related amount of the rotational speed of the wheel acquired by the speed related amount acquiring means.

  According to the brake system, an abnormality of the parking brake is detected based on the related amount of the cable winding force and the related amount of the rotational speed of the wheel. The “related amount of the cable winding force” here refers to, for example, the cable winding force itself, the amount of current supplied to the electric winding means that determines the cable winding force, the cable tension, or the cable winding force. Other state quantities to be included. The “related amount of wheel rotation speed” includes, for example, the wheel rotation speed itself, the acceleration / deceleration speed of the wheel rotation speed during a predetermined time, or other state quantities related to the wheel rotation speed.

  The abnormality detection means includes a related amount of the cable winding force acquired by the winding force acquisition means, a related amount of the rotational speed of the wheel acquired by the speed related amount acquisition means, and the winding force of the cable. It is also possible to detect an abnormality of the parking brake by comparing the predicted value of the related amount and the predicted value of the related amount of the rotational speed of the wheel. According to the brake system, an abnormality of the parking brake can be detected easily and accurately.

  The winding control means refers to the electric hoisting with reference to the related amount of the cable winding force acquired by the hoisting force acquisition means and the related amount of the rotational speed of the wheel acquired by the speed related amount acquisition means. The control of the means can also be corrected. According to the brake system, it is possible to generate a desired braking force with high accuracy.

  The abnormality detection means can also detect an abnormality of the cable from the acquisition result of the winding force acquisition means and the acquisition result of the speed related quantity acquisition means at the initial stage of winding of the cable by the electric winding means. According to the brake system, when an abnormality occurs in the parking brake due to a cable failure, it is possible to specify that the abnormality is caused by the cable.

  The abnormality detection means can also detect an abnormality of the parking brake according to a traveling environment of a vehicle on which the brake system is mounted. According to the brake system, it is possible to accurately detect an abnormality in the parking brake under a traveling environment suitable for detecting an abnormality in the parking brake.

  When the abnormality detection unit detects an abnormality of the parking brake, the abnormality detection unit may further include an abnormality notification unit that notifies the occurrence of the abnormality. According to the brake system, when an abnormality occurs in the parking brake, the abnormality is notified to the vehicle driver or the like, so that safety can be improved.

  The timing for detecting the abnormality of the parking brake by the abnormality detection means may be based on a predetermined abnormality detection interval. For example, the predetermined abnormality detection interval can be determined based on time or can be determined based on the number of times the parking brake is operated. In this case, the abnormality of the parking brake can be detected after the predetermined time has elapsed or the parking brake has been operated a predetermined number of times, and the abnormality of the parking brake can be detected efficiently.

  The abnormality detection means can also detect an abnormality of the parking brake when a vehicle driver or the like instructs the generation of a braking force when the vehicle equipped with the brake system is traveling. For example, the vehicle has an electric hydraulic brake, and when the vehicle driver or the like gives an instruction to generate a braking force by the electric hydraulic brake, part or all of the braking force based on the instruction is given. It is also possible to detect an abnormality in the parking brake by generating the parking brake. The vehicle has engine braking means for generating a braking force in accordance with an operating state of the engine, and the abnormality detecting means is configured when the vehicle driver instructs generation of the braking force by the engine braking means. It is also possible to detect an abnormality of the parking brake by generating a part or all of the braking force based on the instruction with the parking brake. In such a case, the vehicle driver or the like expects the vehicle 10 to be decelerated by the engine brake or the hydraulic brake, so the vehicle driver or the like is also informed by the operation of the parking brake when the parking brake abnormality is detected. It is possible to suppress a sense of incongruity that can be caused.

  It should be noted that a combination of the above-described elements as appropriate, a recombination thereof, or a representation of the present invention in a different expression form such as a method can also be included in the scope of the invention for which protection by patent is sought by this patent application.

  According to the brake system of the present invention, it is possible to accurately detect an abnormality in the parking brake based on the related amount of the cable winding force and the related amount of the rotational speed of the wheel.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram illustrating an overall configuration of a vehicle 10 including the brake system according to the first embodiment.

  The vehicle 10 includes a right front wheel 12a provided at the front right of the vehicle body, a left front wheel 12b provided at the left front of the vehicle body, a right rear wheel 12c provided at the right rear of the vehicle body, and a left rear provided at the left rear of the vehicle body. A ring 12d is provided. Hereinafter, the right front wheel 12a, the left front wheel 12b, the right rear wheel 12c, and the left rear wheel 12d are collectively referred to as “wheels 12”. Further, the right front wheel 12a and the left front wheel 12b are collectively referred to as “front wheels 12a, 12b”, and the right rear wheel 12c and the left rear wheel 12d are collectively referred to as “rear wheels 12c, 12d”. The front wheels 12a, 12b and the rear wheels 12c, 12d are connected by a shaft 14, respectively.

  Each wheel 12 is provided with a brake unit 30 that generates braking force to suppress the rotation of the wheel 12 and a wheel speed sensor 22 that detects the rotation speed of the wheel 12 (hereinafter also referred to as “wheel speed”). Yes. As the brake unit 30, for example, a disc brake device in which a brake pad is pressed against a disc rotor, a drum brake device in which a brake shoe is pressed against a brake drum, and the like are preferably used.

  The vehicle body has a hydraulic brake electric drive unit 32 connected to each brake unit 30 through a hydraulic pipe 16 and a parking brake electric unit connected through a cable 18 to a brake unit 30 attached to the rear wheels 12c and 12d. A drive unit 34 is provided. A hydraulic pressure detection sensor 24 is attached to the hydraulic pipe 16, and a tension sensor 26 is attached to the cable 18. An electronic control unit (hereinafter referred to as “ECU”) 20 is connected to the hydraulic brake electric drive unit 32, the parking brake electric drive unit 34, the hydraulic pressure detection sensor 24, the tension sensor 26, and the wheel speed sensor 22. A parking brake input device 36, a hydraulic brake input device 38, an accelerator detection unit 40, a gear detection unit 42, a gravity element detection unit 44, and a notification device 46 are further connected to the ECU 20.

  The hydraulic brake electric drive unit 32 receives an instruction from the ECU 20, controls the hydraulic pressure of a predetermined liquid filled in the hydraulic pipe 16, and controls the braking force generated by each brake unit 30. The hydraulic pressure level of the predetermined liquid in the hydraulic pipe 16 is detected by the hydraulic pressure detection sensor 24, and the detection result is sent from the hydraulic pressure detection sensor 24 to the ECU 20. The hydraulic pipes 16 connected to the brake units 30 of the front wheels 12a and 12b are in communication with each other, and the predetermined liquid inside shows substantially the same hydraulic pressure. Similarly, the hydraulic pipes 16 connected to the brake units 30 of the rear wheels 12c and 12d are in communication with each other, and predetermined liquids in the interior show substantially the same hydraulic pressure. The hydraulic brake according to the present embodiment includes a brake unit 30 and a hydraulic pipe 16 attached to each wheel.

  The parking brake electric drive unit 34 receives an instruction from the ECU 20, controls the tension of the cable 18, and controls the braking force generated by the brake unit 30 attached to the rear wheels 12c and 12d. The parking brake electric drive unit 34 includes a cable winding machine 33 that winds up the cable 18 to operate the brake unit 30 and a motor 35 that drives the cable winding machine 33. The tension of the cable 18 is detected by the tension sensor 26, and the detection result is sent from the tension sensor 26 to the ECU 20. A current sensor 37 and a torque sensor 39 are attached to the motor 35. The current sensor 37 detects the amount of applied current supplied from the battery (not shown) to the motor 35 and sends the detection result to the ECU 20. The torque sensor 39 detects the torque actually output from the motor 35 to drive the cable winder 33 and sends the detection result to the ECU 20. In addition, the parking brake of this Embodiment is comprised including the brake unit 30 and the cable 18 which were attached to the rear-wheels 12c and 12d.

  The parking brake input device 36 receives an instruction from a vehicle driver or the like who desires to generate a desired braking force by the parking brake, and the “target braking force magnitude” or “braking force level” based on the instruction is received. Information on the braking force such as “the rising state at the time of occurrence” is sent to the ECU 20. The specific form of the parking brake input device 36 may be anything as long as the object can be achieved. For example, in addition to the normal lever type and pedal type, the braking force is determined based on the pushing speed and depth of the elastic body such as sponge, and the braking force is determined based on the gripping force and twisting force. To determine the braking force based on the coordinates of the designated position on the XY table, to determine the braking force based on the speed with which the touch pad is rubbed and the pressing behavior on the touch pad, A parking brake input device 36 that determines the braking force based on the loudness of the voice can be used. The lever type or pedal type parking brake input device 36 sends to the ECU 20 a lever lifting amount, a lever lifting force, a lever lifting speed, a pedal depression amount, a pedal depression force, a pedal depression speed, and the like. Based on those instructions sent from the parking brake input device 36, the ECU 20 derives data relating to braking force such as “target braking force magnitude” and “rising state when braking force is generated”. The ECU 20 obtains, for example, the “braking force target value” from the lever lifting amount and lifting force, the pedal depression amount and the depression force, or sets the “rising state when the braking force is generated” and the “braking force generation mode” It is also possible to determine whether to use the time generation mode or the emergency generation mode based on the lever lifting speed or the pedal depression speed. Note that the ECU 20 can derive data relating to braking force by appropriately using or weighting a plurality of instructions sent from the parking brake input device 36 according to the driving environment. Even when the form of the parking brake input device 36 is other than the lever type or the pedal type, an instruction from a vehicle driver or the like corresponding to the form is sent from the parking brake input device 36 to the ECU 20.

  The hydraulic brake input device 38 receives an instruction from a vehicle driver or the like who desires to generate a braking force having a desired magnitude by the hydraulic brake, and sends the instruction to the ECU 20. The specific form of the hydraulic brake input device 38 may be anything as long as the object can be achieved, and a pedal type hydraulic brake input device 38 is usually used. In this case, the pedal depression amount, pedal depression force, pedal depression speed, and the like are sent from the hydraulic brake input device 38 to the ECU 20. Based on those instructions sent from the hydraulic brake input device 38, the ECU 20 derives data relating to braking force such as “target braking force magnitude” and “rising state when braking force is generated”. The ECU 20 obtains, for example, the “braking force target value” from the pedal depression amount and the depression force, or determines whether the “rising state when the braking force is generated” or the “braking force generation mode” is the normal generation mode. It is also possible to determine whether to use the emergency generation mode based on the pedal depression speed. Note that the ECU 20 can derive data relating to braking force by appropriately using or weighting a plurality of instructions sent from the hydraulic brake input device 38 in accordance with the traveling environment. Even when the form of the hydraulic brake input device 38 is other than the pedal type, an instruction from a vehicle driver or the like corresponding to the form is sent from the hydraulic brake input device 38 to the ECU 20.

  The accelerator detection unit 40 receives an instruction from a vehicle driver or the like who desires the vehicle 10 to generate a desired acceleration, and sends the instruction to the ECU 20. The specific form of the hydraulic brake input device 38 may be any form as long as the object can be achieved, and a pedal type accelerator detector 40 is usually used. In that case, the pedal depression amount, pedal depression force, pedal depression speed, and the like are sent from the accelerator detection unit 40 to the ECU 20. The ECU 20 determines, for example, the “target value of vehicle acceleration” from the pedal depression amount and the depression force, or determines whether the “rising state when the vehicle acceleration is generated” or “vehicle acceleration generation mode is the normal generation mode. It is also possible to determine whether to use the emergency generation mode based on the pedal depression speed. Note that the ECU 20 can derive data related to vehicle acceleration by appropriately using or weighting a plurality of instructions sent from the accelerator detection unit 40 according to the driving environment. Even when the form of the accelerator detection unit 40 is other than the pedal type, an instruction from a vehicle driver or the like corresponding to the form is sent from the accelerator detection unit 40 to the ECU 20.

  The gear detection unit 42 detects information about gears used in a transmission (not shown) of the vehicle 10 and sends the information to the ECU 20. In the transmission, for example, when a low-rotation gear that relatively reduces the wheel speed is used, or in a so-called neutral state in which a force component from the engine is not transmitted to the wheel, the gear detection unit 42 is in that state. Is transmitted to the ECU 20.

  The gravity element detection unit 44 detects the magnitude and direction of force components such as gravity acting on the vehicle 10 and sends the detection result to the ECU 20. Note that the inclination of the road surface on which the vehicle 10 is located can be derived based on the magnitude and direction of the gravity component acting on the stopped vehicle 10.

  The notification device 46 is a device that notifies the vehicle driver or the like when the ECU 20 determines that an abnormality has occurred in the parking brake. The notification device 46 can take any configuration capable of notifying a vehicle driver or the like of a parking brake abnormality. For example, a device that alerts the vehicle driver or the like by an alarm sound or an alarm screen is used. The

  The ECU 20 is configured as a microprocessor including a CPU, and includes a ROM that stores a processing program, a RAM that temporarily stores data, and an input / output port that transmits and receives signals to and from the ECU 20. The ECU 20 controls various devices such as the hydraulic brake electric drive unit 32, the parking brake electric drive unit 34, and the notification device 46 based on information sent from each sensor, electronic device, and the like. Control various states.

  FIG. 2 is a functional block diagram showing functions related to parking brake abnormality detection among various functions of the ECU 20 of the present embodiment. The ECU 20 includes an abnormality detection unit 102, a parking brake control unit 104, a hydraulic brake control unit 106, a storage unit 108, and a notification determination unit 110. The abnormality detection unit 102 includes an abnormality detection timing determination unit 112, an inclination angle determination unit 114, and an abnormality determination unit 116.

  The abnormality detection timing determination unit 112 determines the timing for detecting parking brake abnormality according to the traveling environment of the vehicle 10. In the present embodiment, the parking brake abnormality is detected when the vehicle 10 is parked on the ramp. The abnormality detection unit 102 determines whether or not the vehicle 10 has stopped for parking based on information sent from the wheel speed sensor 22 or the parking brake input device 36, and detects a parking brake abnormality. Determine.

  The tilt angle determination unit 114 determines the tilt angle of the ramp on which the vehicle 10 is parked. In the present embodiment, the inclination angle of the ramp is determined based on the detection value of the gravity element detection unit 44.

  The abnormality determination unit 116 applies the parking brake based on the winding force of the cable 18 and the wheel speeds of the rear wheels 12c and 12d according to the abnormality detection timing determined by the abnormality detection timing determination unit 112 according to the traveling environment of the vehicle 10. Determine whether an abnormality has occurred.

  In general, when there is no abnormality in the parking brake, a braking force corresponding to the winding force of the cable 18 is generated in the brake unit 30, and the wheel speeds of the rear wheels 12c and 12d are gradually reduced. On the other hand, when an abnormality has occurred in the parking brake, the braking force generated by the brake unit 30 of the rear wheels 12c and 12d does not necessarily correspond to the winding force of the cable 18, and the wheels of the rear wheels 12c and 12d. The speed behavior is different from that when a normal parking brake is used. Therefore, whether or not an abnormality has occurred in the parking brake can be determined by referring to the function P {F, V} represented by the winding force F of the cable 18 and the wheel speed V. As such a function P, it is possible to use, for example, the following expression (1) expressed by the wheel speed deceleration (V1-V2) and the winding force F of the cable 18 at a predetermined time interval.

  P = (V1-V2) / F Formula (1)

  Since the winding force F of the cable 18 of the present embodiment is substantially equal to the output torque of the motor 35, the winding force F of the cable 18 can be acquired from the detected value of the torque sensor 39. The abnormality determination unit 116 predicts the actual output value of the motor 35 acquired by the torque sensor 39, the actual rotational value of the rear wheels 12c and 12d acquired by the wheel speed sensor 22, and the output torque of the motor 35. The parking brake abnormality is detected by comparing the value and the expected value of the rotational speed of the rear wheels 12c and 12d. And since the rotational speed of the rear wheels 12c and 12d at the time of parking becomes 0, the abnormality determination unit 116 of the present embodiment that detects an abnormality of the parking brake at the time of parking mainly relates to the related amount of the winding force of the cable 18. An abnormality of the parking brake is determined based on the output torque of one motor 35.

  Specifically, the abnormality determination unit 116 stores the output torque of the motor 35 detected by the torque sensor 39 during parking and the actual rotation angle of the rotor of the motor 35 in the abnormality determination table stored in the storage unit 108. By comparing the output torque of the motor 35 and the expected value of the rotation angle of the rotor, it is determined whether or not a parking brake abnormality has occurred. The abnormality determination table stored in the storage unit 108 includes the inclination angle of the slope to be parked, the expected output torque of the motor 35 and the rotation angle of the rotor required for parking at each inclination angle (hereinafter “ This table is also referred to as “nominal value”. Based on the inclination angle of the slope determined by the inclination angle determination unit 114, the abnormality determination unit 116 compares the actual output value of the motor 35 and the rotation angle of the rotor with the nominal value of the abnormality determination table. The abnormality determination unit 116 determines that no abnormality has occurred in the parking brake when the measured value of the output torque of the motor 35 and the measured value of the rotation angle of the rotor are substantially equal to the nominal value, and measured the measured output torque of the motor 35. When the value and the predicted value are different, it is determined that an abnormality has occurred in the parking brake. The actual rotation angle of the rotor of the motor 35 is measured by a rotation angle detector (not shown). For example, when the rotor rotates twice, the rotation angle is detected as 720 degrees.

  In addition, the abnormality determination unit 116 determines whether the abnormality occurring in the parking brake is caused by a failure such as the extension of the cable 18 or a failure such as a brake pad or a brake shoe of the brake unit 30. to decide. In general, when a failure such as elongation occurs in the cable 18, there is a dead zone in which the braking force is not substantially generated in the brake unit 30 in the initial winding stage where “play” due to the extension of the cable 18 exists. . The abnormality determination unit 116 detects the abnormality of the cable 18 by detecting the presence of such a dead zone from the behavior of the output torque of the motor 35. On the other hand, the malfunction of the brake unit 30 is grasped from the behavior of the output torque of the motor 35 and the behavior of the rotational speeds of the rear wheels 12c and 12d other than the initial winding stage of the cable 18. Based on the characteristics of each abnormality, specific factors of the abnormality occurring in the parking brake are grasped. For example, when an abnormality such as elongation occurs in the cable 18, the actual output torque of the motor 35 is smaller than the nominal value in the initial winding stage of the cable 18 due to “play” of the cable 18. The abnormality determination unit 116 determines whether the output torque of the motor 35 is continuously smaller than the nominal value or the output torque of the motor 35 based on the acquisition result of the torque sensor 39 in the initial winding stage of the cable 18 by the parking brake electric drive unit 34. If a large change suddenly appears, it is determined that there is a high possibility that an abnormality such as elongation has occurred in the cable 18. In addition, the abnormality determination unit 116 is highly likely to have an abnormality in the brake unit 30 when the measured value of the output torque of the motor 35 by the torque sensor 39 is larger than the nominal value throughout the abnormality detection period. Judge. The abnormality determination unit 116 sends information related to the abnormality of the parking brake detected in this way to the notification determination unit 110. The determination of the initial winding stage of the cable 18 is performed with reference to the initial position of the motor 35 stored in the storage unit 108.

  Furthermore, the abnormality determination unit 116 detects whether or not the nominal value related to the output torque of the motor 35 referred to when the parking brake control unit 104 controls the parking brake electric drive unit 34 can be corrected. Determine based on the results. Specifically, the abnormality determination unit 116 determines whether or not the abnormality occurring in the parking brake is within the allowable range, and when determining that the abnormality is within the allowable range, detects the output torque of the motor 35. Based on the result, a nominal value that is an expected value of the output torque of the motor 35 is corrected. Thereby, the parking brake control unit 104 is based on the output torque of the motor 35, which is a related amount of the winding force of the cable 18 acquired by the torque sensor 39, and the rotational speed of the wheel 12 acquired by the wheel speed sensor 22. It is possible to correct the control of the parking brake electric drive unit 34 and generate an appropriate braking force by the parking brake.

  The parking brake control unit 104 controls the parking brake electric drive unit 34 to control the winding of the cable 18 by the cable winding machine 33. The parking brake control unit 104 controls the parking brake electric drive unit 34 based on information sent from the parking brake input device 36 in the normal state, and detects an abnormality of the parking brake. The parking brake electric drive unit 34 is controlled on the basis of the instruction from. The parking brake control unit 104 controls the parking brake electric drive unit 34 with reference to the “relationship between the nominal value of the output torque of the motor 35 and the braking force” stored in the storage unit 108 in advance.

  The hydraulic brake control unit 106 controls the hydraulic brake electric drive unit 32 based on information sent from the hydraulic brake input device 38 and controls the hydraulic pressure of a predetermined liquid in the hydraulic pipe 16. Specifically, the hydraulic brake control unit 106 calculates the hydraulic pressure of a predetermined liquid necessary for generating a desired braking force by the hydraulic brake, and outputs a hydraulic control signal based on the calculation result to the hydraulic brake electric drive unit 32. Send to.

  The storage unit 108 stores the above-described abnormality determination table, information related to parking brake abnormality determination determined by the abnormality determination unit 116, control information of the parking brake electric drive unit 34 in the parking brake control unit 104, hydraulic pressure The control information of the hydraulic brake electric drive unit 32 in the brake control unit 106, the initial position of the motor 35, and the like are stored. Each unit of the ECU 20 can read and rewrite various information stored in the storage unit 108 as necessary.

  The notification determination unit 110 determines whether to operate the notification device 46 based on the result of the parking brake abnormality determination in the abnormality determination unit 116. The notification determination unit 110 activates the notification device 46 when determining that an abnormality to be notified to the vehicle driver or the like has occurred in the parking brake based on the information sent from the abnormality determination unit 116. The notification determination unit 110 does not operate the notification device 46 when determining that there is no abnormality to be notified to the vehicle driver or the like.

  In the vehicle 10 described above, an electric hoisting control unit is configured by the parking brake electric drive unit 34, a hoisting force acquiring unit is configured including the torque sensor 39, and a speed related amount acquiring unit is configured including the wheel speed sensor 22. The ECU 20 constitutes a winding control means and an abnormality detection means.

  Next, the operation of the present embodiment will be described.

  The braking force generated by each brake unit 30 is electrically controlled by the hydraulic brake electric drive unit 32 and the parking brake electric drive unit 34. Therefore, the operation force of the parking brake input device 36 or the hydraulic brake input device 38 by a vehicle driver or the like does not necessarily correspond to the braking force generated by each brake unit 30. A parking brake and a hydraulic brake can be realized without linking the operation of the parking brake input device 36 or the hydraulic brake input device 38 with the operation of the brake unit 30 via the hydraulic pipe 16 or the cable 18. . Therefore, by using an electric parking brake and hydraulic brake, it is possible to generate a braking force in the brake unit 30 without operating the parking brake input device 36 or the hydraulic brake input device 38. Therefore, even when the vehicle driver or the like is not operating the parking brake input device 36 or the hydraulic brake input device 38, the braking force can be generated electrically by the parking brake or the hydraulic brake. Even when the braking force is generated in this way, it is possible to prevent the parking brake input device 36 and the hydraulic brake input device 38 from operating arbitrarily. In the present embodiment, in view of the characteristics of the electric type parking brake as described above, an abnormality in the parking brake is detected as follows.

  FIG. 3 is a flowchart showing an overall flow of a process of detecting an abnormality in the parking brake.

  First, the abnormality detection timing determination unit 112 determines whether or not it is a timing for detecting an abnormality in the parking brake (S11 in FIG. 3). If it is determined that it is not the timing for detecting an abnormality in the parking brake (NO in S11), the current detection of the abnormality in the parking brake is skipped. If it is determined that it is the timing for detecting an abnormality in the parking brake (YES in S11), the inclination angle of the parked ramp is determined by the inclination angle determination unit 114, and the abnormality in the parking brake is determined as an abnormality determination unit. It is detected at 116 (S12).

  The abnormality determination unit 116 determines the output torque value of the motor 35 during parking detected by the torque sensor 39 and the rotor detected by the rotation angle detector based on the inclination angle of the slope determined by the inclination angle determination unit 114. The rotation angle is compared with the nominal value of the output torque of the motor 35 and the rotation angle of the rotor in the abnormality determination table stored in the storage unit 108 to determine whether an abnormality has occurred in the parking brake. . Further, the abnormality determination unit 116 determines that the parking brake abnormality is mainly caused by the behavior of the detected value of the output torque of the motor 35 by the torque sensor 39 and the behavior of the detected values of the rotational speeds of the rear wheels 12c and 12d by the wheel speed sensor 22. Whether the cable 18 is caused by the extension of the cable 18 or the brake unit 30 is determined.

  Then, the notification determination unit 110 determines whether an abnormality to be notified to the vehicle driver or the like has occurred in the parking brake based on the abnormality determination result in the abnormality determination unit 116 (S13). When it is determined that an abnormality to be notified to the vehicle driver or the like has occurred in the parking brake (YES in S13), the notification device 46 is controlled by the notification determination unit 110, and the abnormality is notified to the vehicle driver or the like. (S14). On the other hand, when it is determined that the abnormality that should be notified to the vehicle driver or the like has not occurred in the parking brake (NO in S13), the notification device 46 does not operate and the detection of the abnormality of the parking brake this time is finished.

  Then, the abnormality determination unit 116 determines whether or not the nominal value related to the output torque of the motor 35 referred to when the parking brake control unit 104 controls the parking brake electric drive unit 34 can be corrected (S15). When it is determined that the nominal value related to the output torque of the motor 35 can be corrected (YES in S15), the nominal value of the output torque of the motor 35 is determined to be abnormal based on the actually measured value of the output torque of the motor 35. 116 is corrected. Specifically, the “relationship between the braking force and the nominal value of the output torque of the motor 35” stored in advance in the storage unit 108 is rewritten by the abnormality determination unit 116. Thus, the parking brake electric drive unit 34 is controlled by the parking brake control unit 104, and an appropriate braking force is generated in the brake units 30 of the rear wheels 12c and 12d. If it is determined that correction of the nominal value related to the output torque of the motor 35 is not possible (NO in S15), the current detection of the parking brake abnormality is terminated.

  As described above, in the present embodiment, parking brake abnormality can be detected based on the degree of deviation between the actual value of the output torque of the motor 35 and the nominal value, and in particular, the cable 18 and the brake unit 30 can be detected. It is possible to detect which one of them is abnormal. As a result, even if it is an electric parking brake, a vehicle driver or the like can accurately grasp the occurrence of an abnormality in the parking brake, and can accurately identify the source of the abnormality occurring in the parking brake. is there.

  Further, by correcting the nominal value related to the output torque of the motor 35 that is referred to when the parking brake control unit 104 controls the parking brake electric drive unit 34, an appropriate control is performed. Power can be generated by the parking brake. In particular, in the present embodiment, since all the deviations between the actual output torque value and the nominal value of the motor 35 are regarded as disturbances and the nominal value is corrected in a feedback manner, abnormalities such as extension of the cable 18 and the brake unit 30 are corrected. It is possible to collectively correct errors caused by the abnormalities. Even if there is a variation in performance among products due to manufacturing errors, etc., the nominal value related to the output torque of the motor 35 is corrected as described above, so that the parking brake actually generates the control. It is possible to make the power appropriate.

  Next, a modification of the present embodiment will be described.

  In the above-described embodiment, the example in which the detection result of the torque sensor 39 is referred to when the parking brake abnormality is determined has been described, but the present invention is not limited to this. For example, the detection result of the tension sensor 26 that detects the tension of the cable 18 and the detection result of the current sensor 37 that detects the amount of applied current supplied from the battery to the motor 35 are related to the winding force of the cable 18. It is also possible to determine an abnormality in the parking brake based on other state quantities.

Further, due to the response characteristics of the motor 35, the deviation between the instruction value Fm _ref related to the output torque of the motor 35 sent from the parking brake control unit 104 to the parking brake electric drive unit 34 and the actual output torque value Fm of the motor 35 can be ignored. If the value is extremely small, the output torque value Fm of the motor 35 can be obtained by approximating the instruction value Fm _ref related to the output torque of the motor 35.

  Moreover, although the above-mentioned embodiment demonstrated the example which determines whether abnormality has generate | occur | produced in the parking brake by comparing the data in the abnormality determination table prepared in advance with the actual measurement value, It is not limited to. For example, it is also possible to use a relational expression relating to “the inclination angle of the inclined road to be parked” and “the output torque of the motor 35 and the rotation angle of the rotor required for parking at each inclination angle”. In such a relational expression, a calculation result derived when “the parking brake is in a normal state” is obtained in advance as an ideal value. And it is derived from the above relational expression using the actually detected “inclination angle of the slope to be parked” and “the output torque of the motor 35 and the rotation angle of the rotor required for parking at each inclination angle”. It is also possible to compare the calculation result with the ideal value and determine whether or not an abnormality has occurred in the parking brake from the comparison result.

(Second Embodiment)
In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

The motor 35 has negligible deviation between the instruction value Fm _ref related to the output torque of the motor 35 sent from the parking brake control unit 104 to the parking brake electric drive unit 34 and the actual output torque value Fm of the motor 35 due to response characteristics. What is very small is used. Therefore, the actual output torque value Fm of the motor 35 can be approximated by the instruction value Fm _ref related to the output torque of the motor 35, and the output torque of the motor 35 is determined from the control amount of the parking brake electric drive unit 34 by the parking brake control unit 104. It is possible to obtain the value Fm.

  FIG. 4 is a functional block diagram showing functions related to parking brake abnormality detection among various functions of the ECU 20 of the present embodiment.

  The abnormality detection unit 102 of the ECU 20 of the present embodiment includes an abnormality detection timing determination unit 112 and an abnormality determination unit 116.

  The abnormality detection timing determination unit 112 determines the timing for detecting the parking brake abnormality so that the parking brake abnormality is detected when a so-called engine brake is applied to the vehicle 10. The engine brake is a braking force generated based on the operating state of the engine. In the present embodiment, while the vehicle 10 is traveling, there is no instruction from the vehicle driver or the like regarding the vehicle acceleration via the accelerator detection unit 40, and the vehicle driver or the like regarding the operation of the hydraulic brake via the hydraulic brake input device 38. When there is no instruction and the engine brake generated when the gear for driving the vehicle is used in the transmission acts on the vehicle 10, the abnormality detection of the parking brake system is performed. Therefore, the abnormality detection timing determination unit 112 determines whether or not the vehicle is traveling based on information transmitted from the wheel speed sensor 22 and the parking brake input device 36, and includes the hydraulic brake input device 38, the accelerator, and the like. Based on the information sent from the detection unit 40 and the gear detection unit 42, it is determined whether or not the engine brake is acting on the vehicle 10. In this way, the abnormality detection timing determination unit 112 determines the timing for detecting the parking brake abnormality.

The abnormality determination unit 116 outputs the output torque of the motor 35 and the rotational speed of the rear wheels 12c and 12d, the predicted value of the output torque of the motor 35, and the rear wheels 12c and 12d. An abnormality of the parking brake is detected by comparing with an expected value of the rotation speed. Specifically, the abnormality determination unit 116 determines the rotational speed of the rear wheels 12c and 12d at a predetermined time from an instruction value (hereinafter also referred to as “nominal value of the output torque of the motor 35”) Fm _ref regarding the output torque of the motor 35. An expected value (hereinafter also referred to as “a nominal value of the rotational speed of the rear wheels 12c, 12d”) Vm _ref is calculated. Further, the abnormality determination unit 116 acquires the rotational speed Vm of the rear wheels 12c and 12d at a predetermined time from the detection result of the wheel speed sensor 22. Further, as described above, in the present embodiment, the actual output torque value Fm of the motor 35 is substantially equal to the nominal value Fm _ref of the output torque of the motor 35. Therefore, the abnormality determination unit 116 measures the nominal value Vm _ref of the rotational speeds of the rear wheels 12c and 12d at a predetermined time and the rotational speeds of the rear wheels 12c and 12d at the predetermined time, as shown by the following equation (2). A difference δVm from the value Vm is obtained, and an abnormality in the parking brake is detected based on the δVm.

δVm = | Vm−Vm _ref | Formula (2)

  The abnormality determination unit 116 determines whether or not δVm indicates a value equal to or greater than a predetermined threshold Vt. If δVm is equal to or greater than Vt, the abnormality determination unit 116 determines that an abnormality has occurred in the parking brake, and δVm is equal to Vt. If it is smaller than that, it is determined that there is no abnormality in the parking brake.

  As in the case of the first embodiment, the abnormality determination unit 116 determines whether the abnormality occurring in the parking brake is caused by a malfunction such as the extension of the cable 18 or the brake pad of the brake unit 30. To determine whether it is caused by a malfunction such as a brake shoe. In addition, the abnormality determination unit 116 corrects the nominal value related to the output torque of the motor 35 that is referred to when the parking brake control unit 104 controls the parking brake electric drive unit 34 in the same manner as in the first embodiment. Is determined based on the detection result of the abnormality of the parking brake. The abnormality determination unit 116 corrects the nominal value related to the output torque of the motor 35 so that the motor 35 sent from the parking brake control unit 104 to the parking brake electric drive unit 34 is set so that δVm becomes substantially zero. Adjust the control signal for output torque.

  Other configurations are substantially the same as those of the first embodiment shown in FIGS.

  Also in the present embodiment, the parking brake abnormality is detected in the same manner as in the first embodiment (see FIG. 3). In particular, in the present embodiment, since the parking brake abnormality is detected while the vehicle is traveling, the parking brake abnormality is detected as compared with the first embodiment in which the parking brake abnormality is detected when parking on the slope. There are many chances of detection, and “parking brake abnormality detection” can be performed in a timely manner.

  In addition, since parking brake abnormality detection is performed when the engine brake is applied to the vehicle 10, the braking force is generated by the parking brake without causing a strong sense of discomfort to the vehicle driver, etc., and the parking brake abnormality detection is performed. Is possible.

  Further, since the nominal value of the output torque of the motor 35 is corrected so that δVm becomes substantially 0, a desired braking force is accurately generated in the parking brake, and the parking brake can be operated properly.

(Third embodiment)
In the present embodiment, the same parts as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 5 is a functional block diagram showing functions related to parking brake abnormality detection among various functions of the ECU 20 of the present embodiment.

  In the present embodiment, parking brake abnormality is detected when a vehicle driver or the like intends to generate a braking force by a hydraulic brake. Specifically, while the vehicle 10 is traveling, there is no instruction from the vehicle driver or the like regarding the vehicle acceleration via the accelerator detection unit 40, and an instruction from the vehicle driver or the like regarding the operation of the hydraulic brake via the hydraulic brake input device 38. When there is a parking brake abnormality is detected. Therefore, the abnormality detection timing determination unit 112 detects the parking brake abnormality based on the information sent from the wheel speed sensor 22, the parking brake input device 36, the hydraulic brake input device 38, and the accelerator detection unit 40. Determine.

  The abnormality determination unit 116 detects an abnormality of the parking brake by causing the parking brake to generate all of the braking force that the vehicle driver or the like intends to generate with the hydraulic brake. In other words, the abnormality determination unit 116 causes the parking brake to generate all of the braking force instructed by the vehicle driver or the like via the hydraulic brake input device 38 when the parking brake abnormality is detected, instead of the hydraulic brake. The parking brake control unit 104 and the hydraulic brake control unit 106 are controlled.

  Other configurations are substantially the same as those of the second embodiment shown in FIG.

  Also in the present embodiment, the parking brake abnormality is detected as in the second embodiment (see FIG. 3). In particular, in this embodiment, when a vehicle driver or the like intends to generate a braking force by a hydraulic brake, the parking brake generates a braking force and an abnormality of the parking brake is detected. Therefore, it is possible to detect an abnormality in the parking brake by generating a braking force with the parking brake without causing a sense of incongruity to the vehicle driver or the like.

  In general, the essential intention of a vehicle driver or the like who operates the hydraulic brake input device 38 is to generate a braking force to decelerate the vehicle 10, and there is a strict demand for the method of generating the braking force. There is almost never. Therefore, even when a vehicle driver or the like instructs the generation of braking force via the hydraulic brake input device 38, the desired braking force can be generated smoothly by the electric hydraulic brake and parking brake. it can.

(Fourth embodiment)
In the present embodiment, the same parts as those in the above-described third embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The abnormality determination unit 116 of the present embodiment generates a part of the braking force that the vehicle driver or the like intends to generate by the hydraulic brake, and generates a part by the parking brake and the other part by the hydraulic brake. Detect brake abnormality. Since the hydraulic pipe 16 is connected to the brake units 30 of the front wheels 12a and 12b and the rear wheels 12c and 12d, the hydraulic brake can be applied to all the wheels. On the other hand, since the cable 18 is connected only to the brake units 30 of the rear wheels 12c and 12d, the parking brake can be applied only to the rear wheels 12c and 12d. Therefore, the abnormality determination unit 116 controls the parking brake control unit 104 and the hydraulic brake control unit 106 so that a part of the braking force that the vehicle driver or the like intends to generate by the hydraulic brake is caused by the parking brake. The other parts are applied to the front wheels 12a and 12b by the hydraulic brake.

  Other configurations are substantially the same as those of the third embodiment shown in FIG.

  Also in the present embodiment, parking brake abnormality is detected in the same manner as in the third embodiment (see FIG. 3). In particular, in the present embodiment, only a part of the braking force instructed by the vehicle driver or the like via the hydraulic brake input device 38 is generated by the parking brake. Even when an instruction to generate a large braking force is given, it is possible to appropriately detect a parking brake abnormality by generating a braking force within an allowable range by the parking brake.

  In general, hydraulic brakes are more responsive than parking brakes. For this reason, even if the parking brake and hydraulic brake are applied simultaneously when an abnormality is detected in the parking brake, the possibility of adverse effects on the abnormality detection due to the response of the hydraulic brake is considered to be extremely small. It is done.

  The present invention is not limited to the above-described embodiments and modifications, and any combination of the elements of the embodiments and modifications is also effective as an embodiment of the present invention. Various modifications such as design changes can be added to each embodiment and its modifications based on the knowledge of those skilled in the art, and the embodiment to which such a modification is added is also applicable to the present invention. Can be included in the range.

  For example, when an abnormality occurs in the parking brake, the notification device 46 may report the occurrence of the abnormality to a person concerned such as a dealer of the vehicle 10 using a GPS (Global Positioning System). As a result, the person concerned in the vehicle 10 can quickly grasp the abnormality occurring in the vehicle 10 and can contact the owner of the vehicle 10 for repair or the like as necessary. The notification device 46 can also improve safety by encouraging the vehicle driver or the like to stop the vehicle with the hydraulic brake when an abnormality occurs in the parking brake.

  Moreover, although the above-mentioned embodiment demonstrated the example in which the abnormality detection of a parking brake is performed at the time of parking on an inclined road or a vehicle driving | running | working, it is not limited to this, According to other driving environments It is also possible to detect abnormalities in the parking brake. For example, it is possible to detect the road surface condition with a camera or the like and set the parking brake abnormality detection timing when the vehicle is traveling on a good road surface condition. Moreover, it is also possible to set the parking brake abnormality detection timing when driving on a specific road by combining GPS. When the vehicle travels in the same place, the vehicle tends to travel in the same environment at the same speed. Therefore, there is a tendency that accurate detection with little detection error can be performed by detecting an abnormality of the parking brake when traveling in the same place. In addition, when foreign substances such as moisture adhere to parts such as the rotor of the motor 35 or when the environmental temperature is different, the detection accuracy may vary. For this reason, it is possible to determine the parking brake abnormality detection timing based on, for example, the temperature or weather during vehicle travel. In such a case, for example, the temperature detected by the temperature sensor can be used, or the weather can be determined from the operating condition of the wiper.

  The abnormality detection timing determination unit 112 can also determine the timing for detecting an abnormality of the parking brake with reference to a predetermined abnormality detection interval. For example, it is possible to detect the abnormality of the parking brake as described above after a predetermined time has elapsed, or to detect the abnormality of the parking brake as described above after operating the parking brake a predetermined number of times. More specifically, for example, parking brake abnormality detection can be performed every month, or the parking brake abnormality detection can be performed every time the parking brake is operated 100 times.

  In the hydraulic brakes of the above-described embodiments, a substantially equal braking force is applied to the front wheels 12a and 12b and a substantially equal braking force is applied to the rear wheels 12c and 12d. Is not to be done. For example, when a hydraulic brake that applies a substantially equal braking force to all the wheels 12 included in the vehicle 10 or a hydraulic brake that can apply a different braking force to each of the wheels 12 included in the vehicle 10 is used. Even if it exists, it is possible to apply this invention.

  Further, as the control method of the parking brake electric drive unit 34 and the hydraulic brake electric drive unit 32 by the ECU 20, any method can be adopted as long as the above-described aspects can be realized. For example, not only a method in which the motor 35 is directly controlled by the ECU 20 but also a motor controller for controlling the motor 35 is provided separately, and the motor 20 is indirectly controlled by the ECU 20 controlling the motor controller. It is also possible to use a method of controlling automatically. The ECU 20 also includes a parking brake control unit for controlling the parking brake electric drive unit 34, a hydraulic brake control unit for controlling the hydraulic brake electric drive unit 32, a parking brake control unit, and a hydraulic brake use unit. It is also possible to include a control unit that controls the control unit.

It is a figure showing the whole vehicle composition provided with the brake system of a 1st embodiment. It is a functional block diagram which shows the function relevant to the abnormality detection of a parking brake among the various functions which ECU of 1st Embodiment has. It is a flowchart which shows the whole flow of the process which detects abnormality of a parking brake. It is a functional block diagram which shows the function relevant to the abnormality detection of a parking brake among the various functions which ECU of 2nd Embodiment has. It is a functional block diagram which shows the function relevant to the abnormality detection of a parking brake among the various functions which ECU of 3rd Embodiment has.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle, 12 Wheel, 14 Shaft, 16 Hydraulic pipe, 18 Cable, 20 ECU, 22 Wheel speed sensor, 24 Oil pressure detection sensor, 26 Tension sensor, 30 Brake unit, 32 Hydraulic brake electric drive part, 33 Cable winding machine, 34 Parking brake electric drive unit, 35 motor, 36 parking brake input device, 37 current sensor, 38 hydraulic brake input device, 39 torque sensor, 40 accelerator detection unit, 42 gear detection unit, 44 gravity element detection unit, 46 notification device, 102 An abnormality detection unit, 104 parking brake control unit, 106 hydraulic brake control unit, 108 storage unit, 110 notification determination unit, 112 abnormality detection timing determination unit, 114 inclination angle determination unit, 116 abnormality determination unit.

Claims (6)

A parking brake having a cable;
Electric hoisting means for operating the parking brake by hoisting the cable;
Hoisting control means for controlling the electric hoisting means;
A winding force acquisition means for acquiring a related amount of the winding force of the cable by the electric winding means;
Speed-related amount acquisition means for acquiring a related amount of the rotational speed of the wheel on which the braking force generated by the parking brake acts;
An abnormality detection means for detecting an abnormality of the parking brake based on a related amount of the winding force of the cable acquired by the winding force acquisition means and a related amount of the rotational speed of the wheel acquired by the speed related amount acquisition means; ,
A brake system comprising:   The abnormality detection means includes a related amount of the cable winding force acquired by the winding force acquisition means, a related amount of the rotational speed of the wheel acquired by the speed related amount acquisition means, and the winding force of the cable. The brake system according to claim 1, wherein an abnormality of the parking brake is detected by comparing an expected value of the related amount and an expected value of the related amount of the rotation speed of the wheel.   The winding control means refers to the electric hoisting with reference to the related amount of the winding force of the cable acquired by the hoisting force acquisition means and the related amount of the rotational speed of the wheel acquired by the speed related amount acquisition means. The brake system according to claim 1 or 2, wherein the control of the means is corrected.   The abnormality detection means detects an abnormality of the cable from an acquisition result of the winding force acquisition means and an acquisition result of the speed-related amount acquisition means at an initial stage of winding of the cable by the electric winding means. The brake system according to any one of claims 1 to 3.   The brake system according to any one of claims 1 to 4, wherein the abnormality detection means detects an abnormality of the parking brake according to a traveling environment of a vehicle on which the brake system is mounted. The brake system according to any one of claims 1 to 5, further comprising abnormality notification means for notifying the occurrence of the abnormality when the abnormality detection means detects an abnormality of the parking brake.

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