JP2009121372A - Electric parking brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly start a vehicle after releasing a parking brake in an electric parking brake device with an automatic release function. <P>SOLUTION: An operation release control part 104 transmits a driving signal to an actuator 26 and operates or releases a rear wheel parking brake when it is determined that the starting intention of the vehicle by a driver exists by a starting determination part 102 determining existence/non-existence of starting intention. A map holding part 124 holds an ordinary traveling time map and a starting time map wherein engine torque in starting of the vehicle is set to be larger than in ordinary traveling as maps for setting target engine torque in accordance with an accelerator pedal opening. A map selecting part 106 selects the starting time map when the parking brake is released. A target torque setting part 122 sets the target engine torque by use of the map selected by the map selecting part 106. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric parking brake device.

  In general, an automobile is equipped with a parking brake in addition to a hydraulic brake that generates a braking force by hydraulic pressure, such as a foot brake. The simplest type of parking brake is to drive a wire by pulling an operation lever to operate a brake pad and brake a wheel. However, in recent years, an electric parking brake (EPB) device is also employed in which an actuator is driven or switched by driving an actuator by switching an operation switch or the like by a driver. In the electric parking brake device, when the driver sets the operation switch to the operating side, the actuator is driven and the wire is wound to operate the parking brake, and when the operation switch is set to the release side, the wire is rewound and the parking brake is reversed. Is released.

With such an electric parking brake device, the parking brake can be easily operated and the operation of the parking brake can be electrically controlled. For example, there is a control device that performs smooth and easy automatic start control using the parking brake when starting on a slope, etc., or even if there is no switch operation by the driver, the parking brake is automatically released when the accelerator pedal is depressed. Are known. As an example of the latter, Patent Document 1 discloses an electric parking brake control device in which the parking brake is released when the driver depresses the accelerator pedal and the engine speed corresponds to the inclination angle of the hill when starting on a hill. Has been.
JP 2006-306300 A

  In a vehicle having a parking brake automatic release function (DAR: Drive Away Release) as described above, if the amount of depression of the accelerator pedal is small when starting the vehicle, the engine torque becomes insufficient and the engine stall (engine stall) ) Or start the vehicle smoothly.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technology for smoothly starting a vehicle after releasing the parking brake in an electric parking brake device having an automatic release function.

  One embodiment of the present invention is an electric parking brake device. This device includes a parking brake that is actuated and released by an actuator, a start determination unit that determines whether the driver intends to start the vehicle, and a drive signal to the actuator when it is determined that there is a start intention. As a map for setting the target engine torque according to the accelerator pedal opening, the operation release control unit for releasing the parking brake, the map for normal driving, and the engine torque at the time of vehicle start are higher than those during normal driving A map holding unit that holds a starting map set to have a large torque, a map selecting unit that selects the starting map when the parking brake is released, and a map selecting unit that is selected by the map selecting unit. A target torque setting unit that sets a target engine torque using the map.

  According to this aspect, when the parking brake is automatically released based on the driver's intention to start, a larger engine torque is generated when starting the vehicle than during normal driving, so that torque shortage is avoided and smooth start is possible. Become.

  In the case where the vehicle is a manual transmission vehicle, the map holding unit is configured so that the engine torque when the accelerator pedal is in the first depressing region is set to a value that exceeds a minimum required torque that does not cause an engine stall. A map may be held. As a result, the occurrence of engine stall can be avoided even when the amount of depression of the accelerator pedal is small.

  The start determination unit detects the position of the shift lever, the map holding unit holds a map for starting differently when the shift lever position is forward and reverse, and the map selection unit shifts A starting map corresponding to the lever position may be selected. Thereby, different engine torques can be generated when the vehicle is started forward and when the vehicle is started backward. For example, in the case of reverse, since more careful start is required, the engine torque may be set to be smaller than forward.

  The map selection unit may select the normal travel map after the vehicle has started. As a result, unintended large engine torque is not generated during normal driving, which contributes to improved vehicle fuel efficiency.

  According to the present invention, in the electric parking brake device having the automatic release function, the vehicle can be started smoothly after the parking brake is released.

  FIG. 1 is a configuration diagram of an electric parking brake device 10 according to an embodiment of the present invention. The electric parking brake device 10 is provided in a vehicle together with a hydraulic brake (not shown) that decelerates or stops the vehicle.

  The electric parking brake device 10 includes a hoisting device 28 that is driven by an actuator 26. The hoisting device 28 is configured to wind or unwind the wire 30. A lock piece 32 that engages with the lock pin 40 of the lock mechanism is fixed to the tip of the wire 30. A wire 31 is further fixed to the tip of the lock piece 32, and the tip of the wire 31 is connected to the parking brake 20 provided on the rear wheel of the vehicle, for example. The parking brake 20 is a drum brake, for example. When the hoisting device 28 is driven to wind the wire 30, the wire 31 is also hoisted at the same time, and the parking brake 20 is activated to generate a braking force on the rear wheel. When the hoisting device 28 is driven in the reverse rotation direction and the wire 30 is rewound, the parking brake 20 is released and a non-braking state is established.

  In order to maintain the state of the wire 30 wound up by the hoisting device 28 even after the operation of the actuator 26 is stopped, that is, in order to maintain the braking state of the parking brake 20 after the wire 30 stops in the wound state. The electric parking brake device 10 has a lock mechanism including a lock piece 32 and a lock pin 40. A sawtooth-shaped inclined surface 32 a is formed on one surface of the lock piece 32, and a lock pin 40 having an inclined surface 40 a that engages with the inclined surface 32 a is disposed to face the one surface of the lock piece 32. At the time of winding the wire, the lock piece 32 is pulled upward in FIG. 1. At this time, the slope 40a of the lock pin 40 slides on the slope 32a of the lock piece 32, and the lock pieces 32 are spaced at intervals of the sawtooth-like slope 32a. And the lock pin 40 are engaged. For this reason, the parking brake 20 is not released even if the actuator 26 is not operating.

  The lock pin 40 is always biased in a direction to engage with the lock piece 32 by a biasing means (not shown). The other end of the lock pin 40 is configured as a solenoid 42. The solenoid 42 moves the lock pin 40 in a direction in which the lock pin 40 is separated from the lock piece 32 in accordance with a drive signal from the EPB ECU 100. As a result, the parking brake 20 is released.

  The EPB ECU 100 operates and releases the parking brake in accordance with the on / off of the EPB switch 58. The engine ECU 120 controls the engine speed and engine torque (not shown) by controlling the throttle opening, the ignition timing of the igniter, the fuel injection amount from the injector, and the like based on the vehicle speed, the accelerator opening, the vehicle acceleration, and the like.

  The vehicle speed sensor 50, the shift position sensor 52, the clutch opening sensor 54, and the accelerator opening sensor 56 detect the vehicle speed, the shift lever position, the clutch pedal opening, and the accelerator pedal opening, respectively, and send detection signals to the EPB ECU 100 and the engine. It gives to ECU120.

  FIG. 2 is a functional block diagram showing a configuration of a part related to the present embodiment in the ECUs 100 and 120 of FIG. Each block shown here can be realized in hardware by an element and a mechanical device including a computer CPU and memory, and in software by a computer program or the like. It is drawn as a functional block to be realized. Therefore, those skilled in the art will understand that these functional blocks can be realized in various forms by a combination of hardware and software.

The EPB ECU 100 includes a start determination unit 102, an operation release control unit 104, and a map selection unit 106, and controls the operation and release of the parking brake 20.
The start determination unit 102 determines whether the driver intends to start the vehicle. Specifically, it is determined whether or not the driver has started the vehicle based on the vehicle speed, shift lever position, clutch pedal opening, and accelerator pedal opening obtained from various sensors.
When the start determination unit 102 determines that there is an intention to start, the operation release control unit 104 sends a drive signal to the actuator 26 and the solenoid 42 to release the parking brake. In addition, the operation release control unit 104 drives the actuator 26 or the solenoid 42 according to the on / off state of the EPB switch 58 to operate and release the parking brake.
The map selection unit 106 changes the map selection flag when the parking brake is released by the operation release control unit 104. Specifically, the map selection flag is set to “0” while the parking brake is operating, and the map selection flag is set to “1” when the parking brake is released. This map selection flag is communicated to the target torque setting unit 122 in the engine ECU 120 as needed. In addition, when the map selection unit 106 confirms that the start of the vehicle is completed based on the detection value of the vehicle speed sensor 50, the map selection unit 106 resets the map selection flag to “0”.

Engine ECU 120 includes a target torque setting unit 122 and a map holding unit 124.
The map holding unit 124 is set as a map for setting the target engine torque according to the accelerator pedal opening so that the normal driving map and the engine torque at the start of the vehicle are larger than those during normal driving. Hold the starting map. The map holding unit 124 may hold three or more different types of maps depending on the situation where the vehicle is placed.
The target torque setting unit 122 refers to the map instructed by the map selection unit 106 and sets a target engine torque corresponding to the accelerator pedal opening detected by the accelerator opening sensor 56. The target torque setting unit 122 selects a normal travel map when the map selection flag is “0”, and selects a start map when the map selection flag is “1”. The map may be a two-dimensional map in which the target engine torque is determined only by the accelerator pedal opening, or may be a three-dimensional map in which the target engine torque is determined by the engine speed detected by a rotation speed sensor (not shown) and the accelerator pedal opening. .
Based on this target engine torque, engine ECU 120 controls the target injection amount of the injector, the target opening of the throttle, and the like. Since such an engine control method is well known, detailed description thereof is omitted in this specification.

FIG. 3 is a flowchart showing the control when the parking brake is released according to the present embodiment.
First, the start determination unit 102 determines whether the parking brake is operating, that is, whether the parking brake is locked (S10). For this determination, for example, the operation release control unit 104 may check a flag that changes in response to the operation or release of the parking brake. Alternatively, a displacement sensor may be provided in the vicinity of the lock piece 32, and the operation or release of the parking brake may be determined based on the amount of displacement from the reference position of the lock piece.

  When the parking brake is released (N in S10), the map selection flag remains “0” (S18). When the parking brake is activated, that is, when the parking brake is locked (Y in S10), the start determination unit 102 determines whether or not the vehicle is stopped based on the detection value of the vehicle speed sensor 50 (S12). ). If the vehicle is stopped (Y in S12), the start determination unit 102 determines whether a start operation by the driver has been performed (S14). Specifically, when the shift lever is in the first speed, the clutch pedal moves in the engagement direction, and the accelerator pedal opening is equal to or greater than a threshold value, it is determined that the driver intends to start. When all of these are satisfied at the same time, it may be determined that there is an intention to start, or when any one or two conditions are satisfied, it may be determined that there is an intention to start.

If it is determined that there is an intention to start (Y in S14), the operation release control unit 104 issues a command to the actuator 26 and the solenoid 42 to release the parking brake, and the map selection unit 106 sets the map selection flag to “1”. (S16).
If it is determined that the vehicle is not stopped (N in S12) or the driver does not intend to start (N in S14), the map selection unit 106 sets the map selection flag to “0” (S18). .

  FIG. 4A is a flowchart of the target torque setting unit 122. The target torque setting unit 122 determines whether or not the map selection flag transmitted from the EPB ECU 100 is “1” (S20). When the map selection flag is “1”, the target map based on the accelerator pedal opening is set using the starting map (S22), and when the map selection flag is “0”, the normal driving map (S24) is used. To do.

FIG. 4B is a specific example of the normal travel map and the start map. As shown in the drawing, the horizontal axis represents the accelerator pedal opening, and the vertical axis represents the target engine torque.
In general, the target engine torque in a region where the accelerator pedal opening is relatively small is suppressed to a low value in order to improve fuel efficiency when the vehicle is stopped. However, the vehicle immediately after releasing the parking brake is less likely to rotate the tires than the vehicle immediately after stopping traveling, and a larger torque is required for starting.
As shown in the figure, the starting map is set so that the target torque is larger than the normal driving map in a relatively small region where the accelerator pedal opening degree starts to be depressed. As a result, even when the amount of depression of the accelerator pedal by the driver is small, a larger engine torque is generated than during normal driving.
For example, the torque of the map for starting is set to a torque that does not cause an engine stall when the shift lever is in the first speed position. Such a lower limit value of the torque can be calculated from the characteristics of the transmission.

  Further, as can be seen from FIG. 4B, in the range where the accelerator pedal opening is relatively large, the target engine torque of the map for starting is not different from the map for normal driving. Even in the case of excessive torque, the wheels will not run idle.

  As described above, according to the present embodiment, when the parking brake is automatically released based on the driver's intention to start, a larger engine torque is generated when starting the vehicle than during normal driving. Even when the amount of pedal depression is small, torque shortage is avoided and smooth start is possible. Also, if the vehicle is a manual transmission vehicle, use a starting map that is set so that the engine torque when the accelerator pedal is in the first depressing region exceeds the minimum required torque that does not cause an engine stall. Thus, the occurrence of engine stall can be avoided even when the amount of depression of the accelerator pedal is small.

  The present invention has been described based on some embodiments. These embodiments are merely examples, and modifications such as arbitrary combinations of the embodiments, each component of the embodiments, and any combination of the processing processes are also within the scope of the present invention. It will be understood by those skilled in the art.

  The present invention is not limited to the above-described embodiments, and various modifications such as design changes can be added based on the knowledge of those skilled in the art. The configuration shown in each drawing is for explaining an example, and can be appropriately changed as long as the configuration can achieve the same function.

  In the embodiment, the map holding unit holds a map for setting the engine torque in accordance with the accelerator pedal opening, but may hold a map for setting the target engine output.

  In the embodiment, the start determination unit determines that the driver has an intention to start when the shift lever is in the first speed position. However, the start determination unit may determine that the driver has an intention to start even when the shift lever is in the back position. Good. Further, the map holding unit may hold a back map that is selected when the shift lever is at the back position. The same start map may be used for both forward and reverse travel.

It is a lineblock diagram of the electric parking brake device concerning one embodiment of the present invention. It is a functional block diagram which shows the structure of the part which concerns on this embodiment among ECU100,120 of FIG. It is a flowchart which shows the control at the time of parking brake cancellation | release by one Embodiment. (A) is a flowchart of a target torque setting part, (b) is a figure which shows the specific example of the map for normal driving, and the map for start time.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Electric parking brake device, 20 Parking brake, 26 Actuator, 28 Hoisting device, 30 Wire, 31 Wire, 32 Lock piece, 40 Lock pin, 42 Solenoid, 50 Vehicle speed sensor, 52 Shift position sensor, 54 Clutch opening sensor, 56 accelerator opening sensor, 58 EPB switch, 100 EPB ECU, 102 start determination unit, 104 operation release control unit, 106 map selection unit, 120 engine ECU, 122 target torque setting unit, 124 map holding unit.

Claims (4)

A parking brake that is actuated and released by an actuator;
A start determination unit for determining whether the driver intends to start the vehicle;
When it is determined that the vehicle has an intention to start, an operation release control unit that sends a drive signal to the actuator to release the parking brake;
As a map for setting the target engine torque according to the accelerator pedal opening, a map for normal driving and a map for starting that is set so that the engine torque when starting the vehicle is larger than that during normal driving A map holding unit for holding
A map selection unit that selects the starting map when the parking brake is released;
A target torque setting unit that sets a target engine torque using the map selected by the map selection unit;
An electric parking brake device comprising: The vehicle is a manual transmission vehicle;
The map holding unit holds a starting map that is set such that the engine torque when the accelerator pedal is in the first depressing region exceeds a minimum required torque that does not cause an engine stall. The electric parking brake device according to claim 1. The start determination unit detects the position of the shift lever,
The map holding unit holds a map for starting at different times when the shift lever position is forward and reverse.
The electric parking brake device according to claim 1 or 2, wherein the map selection unit selects a starting map according to a shift lever position.   4. The electric parking brake device according to claim 1, wherein the map selection unit selects the map for normal driving after the vehicle starts. 5.

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