JP6027482B2 - Electric parking brake system - Google Patents

Description

  The present invention relates to an electric parking brake system.

  As a conventional electric parking brake system, for example, one described in Patent Document 1 below is known. Patent Document 1 includes an electric motor, a driving force transmission mechanism connected to the electric motor, a wire having one end coupled to the driving force transmission mechanism, and a parking brake connected to the other end of the wire. There is disclosed an electric parking brake that operates a parking brake of a vehicle by driving an electric motor by a signal from a control device of the vehicle.

JP 2003-254367 A

  By the way, if the electric parking brake is released prior to the driver's accelerator pedal operation when the vehicle starts on a slope, the vehicle slips. From the viewpoint of suppressing the risk of vehicle slipping, there is still room for improvement in the electric parking brake system.

  The present invention has been made in view of such circumstances, and provides an electric parking brake system capable of suppressing vehicle slippage when starting a hill by appropriately changing the release time of the electric parking brake. The task is to do.

  In order to solve the above-described problems, an electric parking brake system according to the present invention is an electric parking brake system including an electric parking brake that applies a braking force to a vehicle, and includes a control unit that controls the electric parking brake, and electric parking. A control unit comprising: a PKB operation switch for switching between a brake operation state and a release state; a shift range detection unit that detects a shift range of the vehicle; and a pedal operation detection unit that detects an operation of an accelerator pedal of the vehicle. Compared to when the shift range is a position where the vehicle can be driven and the operation of the accelerator pedal is detected within a predetermined time when the electric parking brake is switched from the activated state to the released state by the PKB operation switch. At other times, the operation switch can be switched Extend the release time until parking brake is released, characterized in that.

  According to the electric parking brake system of the present invention, even if the driver switches the electric parking brake to the released state by the operation switch, the shift range is a position where the vehicle can be driven, and the accelerator pedal is within a predetermined time. Since the electric parking brake release time is extended except when the operation of the vehicle is detected, the driver can operate the accelerator pedal with a sufficient margin and suppresses vehicle slippage when starting on a slope. can do.

In the electric parking brake system according to the present invention, the control unit extends the release time and before the electric parking brake is released, the shift range is a position where the vehicle can be driven, and the accelerator pedal is operated. When detected, the release time may be shortened.
According to this electric parking brake system, even after the release time is extended, the shift range is a position where the vehicle can be driven and the operation of the accelerator pedal is detected before the electric parking brake is released. Sometimes, the driver's convenience can be improved because the waiting time for the driver can be reduced by shortening the release time.

In the electric parking brake system according to the present invention, the electric parking brake includes a parking brake of the vehicle, a cable connected to the parking brake, and an actuator that winds and sends out the cable. When releasing the parking brake by extending the length of the cable from the PKB operation stroke to the PKB release stroke and extending the release time, from the delivery speed from the PKB operation stroke to the predetermined intermediate stroke, The feeding speed from the intermediate stroke to the PKB release stroke may be reduced.
According to this electric parking brake system, when extending the release time, the cable is first sent out at a high sending speed, and then the sending speed is set low, so that the driver is compared with the case where the sending speed is uniformly reduced. The cable length when the shift range and the accelerator pedal operation are detected becomes close to the PKB release stroke, and the electric parking brake can be released quickly in a short time.

The electric parking brake system according to the present invention may further include an inclination detection unit that detects the inclination of the vehicle, and the control unit may change the release time based on the vehicle inclination detected by the inclination detection unit.
According to this electric parking brake system, the release time can be changed in accordance with the inclination of the vehicle (road gradient). Convenience can be improved by reducing the release time and shortening the waiting time of the driver by suppressing the fall and changing the release time short when the vehicle is sloping.

  According to the present invention, by appropriately changing the release time of the electric parking brake, the vehicle can be prevented from slipping when starting on a slope.

It is the schematic which shows the structure of the electric parking brake system which concerns on one Embodiment. It is a graph for demonstrating normal cancellation | release of PKB. It is a graph for demonstrating extension of the cancellation | release time of PKB. It is a flowchart for demonstrating cancellation | release operation | movement of an electric parking brake system.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating a configuration of an electric parking brake system according to an embodiment. As shown in FIG. 1, the electric parking brake system 1 of this embodiment is mounted on a vehicle V, and includes an accelerator pedal sensor 5, an electric parking brake (Electronic Parking Brake) 10, a shift sensor 20, and the like. , G sensor 30, PKB operation switch 40, and ECU (Electronic Control Unit) 50.

  Examples of the vehicle V include large vehicles such as trucks, buses, and heavy machinery, and medium-sized vehicles. Further, the vehicle V to be applied is not limited, and may be a normal passenger car, a small vehicle, a light vehicle, or the like.

  The accelerator pedal sensor 5 detects the operation of the accelerator pedal of the vehicle V, and is electrically connected to the ECU 50. The accelerator pedal sensor 5 is provided for the accelerator pedal, and outputs a detection signal of the operation amount (depression amount) of the accelerator pedal to the ECU 50. The accelerator pedal sensor 5 corresponds to pedal operation detecting means described in the claims.

  The electric parking brake 10 is an electric parking brake for braking the vehicle V, and includes an actuator 11, a cable 12, and a PKB (Parking Brake: parking brake mechanism) 13. In the electric parking brake 10, the actuator 11 including the electric motor is operated and the cable 12 is wound up, whereby the PKB 13 is driven and a desired braking force is applied to the rear wheel H of the vehicle V.

  The actuator 11 is electrically connected to the ECU 50, and the winding and sending of the cable 12 are controlled by the ECU 50. The cable 12 is a brake wire connected to the actuator 11 and the PKB 13. In the illustrated example, the cable 12 extends from the actuator 11 forward between the driver seat D and the passenger seat P in the vehicle V, for example, and then bends so as to pass through the front side and the right side of the driver seat D. And is connected to the PKB 13.

  The PKB 13 employs a center brake drum brake or the like, and is installed behind the transmission 2. The PKB 13 presses the shoe against the drum, for example, according to the pulling of the cable 12, thereby restraining the propeller shaft 3. The PKB 13 is not limited in its configuration and method, and may be used as a service brake mechanism installed in the wheel H, or a parking brake mechanism different from the service brake mechanism may be used in the wheel H. It may be built-in. Further, the electric parking brake 10 is not limited to the one using the cable 12, and an air brake mechanism or a hydraulic brake mechanism using compressed air may be adopted for the operation.

  The shift sensor 20 is a shift range detection unit that detects the shift range (operation position of the shift lever) of the vehicle V. For example, when the transmission 2 is an AMT (automatically controlled manual transmission), the shift sensor 20 is any one of a D range for automatic transmission, an S range for manual shift, an N range for neutral, and an R range for reverse. It is detected whether the shift lever is located at. A range other than the N range is a shift range in which the vehicle V can be driven by the engine power. The shift sensor 20 outputs a shift range detection signal to the ECU 50.

  The G sensor 30 is an acceleration sensor that detects the acceleration of the vehicle V, and detects the acceleration in the front-rear direction of the vehicle V. The G sensor 30 is electrically connected to the ECU 50 and outputs the detected value to the ECU 50. The ECU 50 obtains the inclination of the vehicle V (the inclination in the front-rear direction, that is, the road gradient) using the detection result of the G sensor 30. Since the technique for obtaining the inclination of the vehicle V using the detection result of the G sensor 30 is a well-known technique, the description thereof is omitted. The G sensor 30 and the ECU 50 function as an inclination detection unit that detects the inclination of the vehicle V. A dedicated sensor for detecting the inclination of the vehicle V may be provided separately.

  The PKB operation switch 40 is for switching between an operating state and a released state of the electric parking brake 10 and is electrically connected to the ECU 50. The ECU 50 operates the actuator 11 in response to ON / OFF of the PKB operation switch 40 to operate and release the PKB 13 via the cable 12.

  ECU50 is a control part which controls operation | movement of the electric parking brake 10, for example, is comprised by the computer containing CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory).

  In this ECU 50, when the PKB operation switch 40 is switched from OFF to ON, the cable 12 is wound up by the electric motor of the actuator 11 until the length of the cable 12 changes from the PKB release stroke to the PKB operation stroke, and the PKB 13 is in the operating state. Switch to Here, the PKB release stroke means a sufficiently long stroke of the cable 12 for reliably releasing the PKB 13, that is, a stroke for sufficiently reducing the tensile load of the cable 12 for releasing the PKB 13. The PKB operation stroke means a sufficiently short stroke of the cable 12 at which the PKB 13 starts to operate reliably, that is, a stroke in which the tensile load of the cable 12 becomes sufficiently large due to the operation of the PKB 13.

  On the other hand, in this ECU 50, when the PKB operation switch 40 is switched from ON to OFF, the cable 12 is sent out by the electric motor of the actuator 11 until the length of the cable 12 reaches the PKB release stroke, and the PKB 13 is switched to the release state. .

  At this time, the ECU 50 according to the present embodiment detects the operation state of the driver and the inclination of the vehicle V and changes the release time. The release time is the time from when the PKB operation switch 40 is switched from ON to OFF until the electric parking brake 10 (PKB 13) is released. Hereinafter, the change of the release time will be described with reference to FIGS. 2 and 3.

  FIG. 2 is a graph for explaining normal PKB release. FIG. 3 is a graph for explaining the extension of the PKB release time. 2 and 3, the upper graph shows the relationship between the stroke (vertical axis) and time (horizontal axis) of the cable 12, and the lower graph shows ON / OFF signal switching of the PKB operation switch 40 (vertical axis). ) And time (horizontal axis).

  In the ECU 50, when the PKB operation switch 40 is switched from ON to OFF and the effective accelerator pedal operation is not detected within a predetermined determination time, the normal PKB release shown in FIG. 2 is performed. The effective operation of the accelerator pedal means an operation of the accelerator pedal performed when the shift range is a position where the vehicle V can be driven (in the present embodiment, other than the N range).

  In the normal PKB release shown in FIG. 2, the ECU 50 starts feeding the cable 12 by the actuator 11 in response to the switching of the PKB operation switch 40 from ON to OFF, and the length of the cable 12 changes from the PKB operation stroke to the PKB. The PBK 13 is released by reaching the release stroke. At this time, the feeding speed of the cable 12 by the actuator 11 is constant.

  On the other hand, in the ECU 50, when the PKB operation switch 40 is switched from ON to OFF, when the shift range is a position where the vehicle can be driven and the operation of the accelerator pedal is detected within a predetermined time, FIG. Extension of the release time shown in

  In the extension of the release time shown in FIG. 3, the ECU 50 starts sending out the cable 12 by the actuator 11 in response to switching of the PKB operation switch 40 from OFF to ON, but the shift range described above within a predetermined determination time. When the position and the operation of the accelerator pedal are not detected, the release time is extended by slowing the feeding speed of the cable 12.

  Specifically, as shown in FIG. 3, the ECU 50 extends the release time by slowing the delivery speed from the intermediate stroke to the PKB release stroke from the delivery speed from the PKB operation stroke to the predetermined intermediate stroke. . The delivery speed corresponds to the slope of the graph.

  Note that the delivery speed is not necessarily changed in two stages, may be changed in three stages, and may be changed in four stages or more. In this embodiment, the stroke of the cable 12 at the end of the determination time matches the intermediate stroke. However, it is not always necessary to match the stroke, and the stroke of the cable 12 at the time after the determination time has elapsed is determined as the intermediate stroke. It is good. That is, even after the determination time has elapsed, the cable 12 may be sent out at a constant delivery speed, and after the length of the cable 12 reaches a predetermined intermediate stroke, it may be switched to a slower delivery speed.

  Further, the ECU 50 changes the release time according to the forward / backward inclination (road slope) of the vehicle V obtained from the detection result of the G sensor 30. Specifically, the ECU 50 increases the release time as the inclination of the vehicle V is steep, and shortens the release time as the inclination of the vehicle V is gentle. The change of the release time is performed both in the case of normal PKB release shown in FIG. 2 and in the case of extension of the release time shown in FIG. It should be noted that the release time is changed long only when the inclination of the vehicle V is equal to or greater than the predetermined steep slope threshold, and the release time is changed short only when the inclination of the vehicle V is equal to or less than the predetermined low gradient threshold. Good.

  Next, the release operation of the electric parking brake system 1 will be described with reference to FIG. FIG. 4 is a flowchart showing the release operation of the electric parking brake system 1.

  As shown in FIG. 4, as step S1, the ECU 50 detects switching of the PKB operation switch 40 from ON to OFF. Then, as the next step S2, the ECU 50 detects the current inclination of the vehicle V. In this embodiment, ECU50 detects the inclination of the vehicle V using the detection result of G sensor 30, and changes the length of the cancellation | release time used as a basis based on a detection result.

  Thereafter, as step S3, the ECU 50 determines whether or not the operation of the accelerator pedal is detected within a predetermined determination time in the shift range in which the vehicle V can be driven based on the detection results of the accelerator pedal sensor 5 and the shift sensor 20. Determine the conditions.

  When it is determined that the condition of step S3 is satisfied, the ECU 50 performs normal PKB release as shown in FIG. 2 as step S4. In normal PKB release, the ECU 50 sends out the cable 12 at a constant delivery speed, and the PBK 13 is released when the length of the cable 12 reaches from the PKB operation stroke to the PKB release stroke. Thereby, the cancellation | release operation | movement of the electric parking brake system 1 is complete | finished.

  On the other hand, when it is determined that the condition of step S3 is not satisfied, the ECU 50 extends the PKB release time as shown in FIG. 3 as step S5. The ECU 50 feeds the cable 12 at a constant feed speed until the length of the cable 12 reaches from the PKB operation stroke to the intermediate stroke, and then the slower feed speed until the length of the cable 12 reaches from the intermediate stroke to the PKB release stroke. By extending the release time.

  When the release time is extended, the ECU 50 determines a condition as to whether or not an accelerator pedal operation is detected within a predetermined determination time in the shift range in which the vehicle V can be driven before releasing the PKB, as step S6. When the ECU 50 determines that this condition is not satisfied, it keeps the release time extended, and the release operation of the electric parking brake system 1 ends by releasing the PBK 13 when the release time ends.

  On the other hand, when it is determined that the condition of step S6 is satisfied, the ECU 50 shortens the release time as step S7. The ECU 50 shortens the release time by increasing the delivery speed of the cable 12 by the actuator 11, and releases the PKB 13 quickly in a short time after the condition of step S6 is satisfied. Thereby, the cancellation | release operation | movement of the electric parking brake system 1 is complete | finished.

  According to the electric parking brake system 1 according to the present embodiment described above, even if the driver switches the PKB operation switch 40 from ON to OFF, the shift range is a position where the vehicle can be driven (N range in the present embodiment). The operation time of the electric parking brake 10 is extended except when the operation of the accelerator pedal is detected within a predetermined judgment time, so that the driver operates the accelerator pedal with a sufficient margin. It is possible to suppress vehicle slippage when starting on a slope.

  Further, according to the electric parking brake system 1, the shift range is a position where the vehicle can be driven and the predetermined determination is made before the electric parking brake 10 is released even after the release time is extended. Since the release time is shortened when the operation of the accelerator pedal is detected within the time, the waiting time for the driver to release the electric parking brake can be shortened, and convenience can be improved.

  Furthermore, according to the electric parking brake system 1, when the release time is extended, the cable 12 is sent out at a high sending speed first, and then a slow sending speed is set. Therefore, compared with the case where the sending speed is uniformly reduced. Thus, the length of the cable 12 when the shift range position change or accelerator pedal operation by the driver is detected becomes close to the PKB release stroke, and the electric parking brake can be released quickly in a short time.

  Further, according to the electric parking brake system 1, when the release time is extended, the cable 12 is first sent out at a high sending speed and then set to a slow sending speed, so that the sending speed is uniformly reduced. In comparison, when the shift range or accelerator pedal operation is detected before the electric parking brake 10 is released, the cable 12 can be sent quickly to the PKB release stroke in a short time without waiting for the driver. The electric parking brake 10 can be released.

  Further, according to the electric parking brake system 1, the release time can be changed according to the inclination of the vehicle (road gradient). For example, when the inclination of the vehicle is steep, the release time is changed to be longer. Convenience can be improved by preventing the vehicle from slipping off and changing the release time short so that the driver does not wait when the vehicle is slanting.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments. The present invention can be modified without departing from the scope described in the claims or applied to other embodiments. May be.

  For example, it is not always necessary to change the release time according to the inclination of the vehicle. Further, the transmission is not limited to AMT. For example, when the shift range has a P range, a shift range other than the N range and the P range is a shift position where the vehicle can be driven.

  DESCRIPTION OF SYMBOLS 1 ... Electric parking brake system, 5 ... Accelerator pedal sensor (pedal detection means), 11 ... Actuator, 12 ... Cable, 13 ... PKB, 10 ... Electric parking brake, 20 ... Shift sensor (shift range detection means), 30 ... G Sensor (inclination detection means), 50 ... ECU (control unit, inclination detection means), V ... vehicle.

Claims (4)

An electric parking brake system having an electric parking brake for applying braking force to a vehicle,
A control unit for controlling the electric parking brake;
A PKB operation switch for switching between an operation state and a release state of the electric parking brake;
Shift range detecting means for detecting the shift range of the vehicle;
Pedal operation detecting means for detecting an operation of an accelerator pedal of the vehicle;
With
When the electric parking brake is switched from the operating state to the released state by the PKB operation switch, the control unit is configured such that the shift range is a position where the vehicle can be driven and the accelerator is operated within a predetermined time. An electric parking brake system characterized by extending a release time from the change of the operation switch to the release of the electric parking brake at other times than when the pedal operation is detected.   When the control unit detects the operation of the accelerator pedal after extending the release time and before the electric parking brake is released, the shift range is a position where the vehicle can be driven. The electric parking brake system according to claim 1, wherein the release time is shortened. The electric parking brake has a parking brake of the vehicle, a cable connected to the parking brake, and an actuator that winds and sends out the cable.
The controller sends out the cable from the actuator, and releases the parking brake by extending the length of the cable from a PKB operation stroke to a PKB release stroke.
3. The delivery speed from the intermediate stroke to the PKB release stroke is made slower than the delivery speed from the PKB operation stroke to a predetermined intermediate stroke when extending the release time. The described electric parking brake system. Further comprising an inclination detecting means for detecting the inclination of the vehicle,
The electric parking brake system according to any one of claims 1 to 3, wherein the control unit changes the release time based on the inclination of the vehicle detected by the inclination detection unit.

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