JP2001322537A - Motor-driven parking brake device and parking brake control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the application of sudden starting torque caused by releasing a parking brake, and to improve comfortableness at start. SOLUTION: Whether or not a brake switch is normal is judged (S106). When the brake switch is normal, the parking brake is released in the state that a shift position SP is in a position capable of traveling and the brake switch BS is turned off (S108 and S112). The deterioration of comfortableness of an occupant caused when driving force suddenly acts on a driving wheel is thereby restrained. When the brake switch is abnormal, the parking brake is released in the state that the shift position SP is in the position capable of traveling and an accelerator switch AS is turned on, (S110 and S112). Abnormality of the brake switch is thereby prevented from becoming unoperable of automatic release in the parking brake.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric parking brake device and a method for controlling a parking brake.
The present invention relates to an electric parking brake device having a parking brake that is activated and released by an electric driving means, and a parking brake control method for releasing a parking brake that is activated when a predetermined departure operation is performed.

[0002]

2. Description of the Related Art Conventionally, as this kind of electric parking brake device, there has been proposed an electric parking brake device which releases a parking brake when a predetermined departure operation is performed (for example, Japanese Patent Application Laid-Open No. Hei 1-1-1).
254456). In this device, when the shift position is at a position where the vehicle can travel and the depressing operation of the accelerator becomes equal to or more than a predetermined value, the parking brake is released assuming that a predetermined departure operation has been performed.

[0003]

However, in such an electric parking brake device, the ride comfort of the occupant may be deteriorated. Since the parking brake is released when the accelerator operation is equal to or more than a predetermined value, that is, when a predetermined driving force is applied, the driving force is rapidly applied to the driving wheels when the parking brake is released. Works. As a result, a sudden start torque acts on the occupant, and the ride comfort deteriorates compared to a smooth start.

[0004] An object of the present invention is to suppress the action of a sudden starting torque associated with the release of a parking brake. Another object of the present invention is to provide a parking brake device and a parking brake control method that improve the riding comfort at the time of starting.

[0005]

Means for Solving the Problems and Their Functions and Effects The electric parking brake device and the control method of the parking brake according to the present invention employ the following means in order to at least partially achieve the above-mentioned object.

An electric parking brake device according to the present invention is an electric parking brake device having a parking brake that is operated and released by an electric driving means, wherein a shift position detecting means for detecting a shift position, and an operating state of a service brake. A brake operation state detecting means for detecting a position of the service brake detected by the shift position detecting means and a state in which the operation of the service brake is released by the brake operation state detecting means. And control means for controlling the electric drive means so as to cancel the condition.

In the electric parking brake device of the present invention,
The parking brake is released when the shift position at which travel is possible is detected by the shift position detecting means and the state where the operation of the service brake is released is detected by the brake operating state detecting means. That is, since the parking brake is released in a state where the driving force due to the operation of the accelerator is not acting, the driving force does not suddenly act on the driving wheels. As a result,
Deterioration of the riding comfort at the time of starting can be suppressed.

In the electric parking brake device of the present invention, the electric parking brake device includes abnormality detecting means for detecting abnormality of the brake operation state detecting means, and accelerator operation state detecting means for detecting an accelerator operation state. When the abnormality detecting means detects an abnormality of the brake operation state detecting means, the shift position detecting means detects a shift position at which the vehicle can travel, and the accelerator operation state detecting means detects a state in which the accelerator is operated. In this case, the parking brake may be released when the parking brake is released. In this case, even if an abnormality occurs in the brake operation state detecting means, the parking brake can be released by operating the accelerator.

Further, in the electric parking brake device of the present invention, there is provided running state detecting means for detecting a running state of the vehicle, and the control means detects when the running state of the vehicle is stopped by the running state detecting means. Means for performing control for releasing the parking brake.

A parking brake control method according to the present invention is a parking brake control method for releasing a parking brake that is being operated when a predetermined departure operation is performed. The gist of the present invention is to release the parking brake when it is detected and when the operation of the service brake is released.

According to the parking brake control method of the present invention, the parking brake is released when it is detected that the operation of the service brake is released while the shift is in a position where the vehicle can travel, so that the operation of the accelerator is controlled. The parking brake can be released when no driving force is applied. As a result, the driving force does not suddenly act on the driving wheels, and it is possible to suppress the deterioration of the riding comfort when starting.

In the parking brake control method according to the present invention, when the release of the service brake cannot be detected due to abnormality, when the operation of the accelerator is detected instead of detecting the release of the service brake, Alternatively, the parking brake may be released. In this case, the parking brake can be released by operating the accelerator.

[0013]

Next, embodiments of the present invention will be described with reference to examples. FIG. 1 is a configuration diagram schematically showing the configuration of an electric parking brake device 20 according to one embodiment of the present invention. The electric parking brake device 20 of the embodiment includes parking brake units 22 and 24 for applying a braking force to the left and right rear wheels 12 and 14 of the vehicle, and the parking brake units 22 and 24.
A cable 26 connected to the cable 24, a cable winding unit 30 for winding the cable 26 to operate the parking brake units 22 and 24, and an electronic control unit 50 for controlling the entire apparatus are provided.

FIG. 2 is a configuration diagram illustrating the configuration of the cable winding unit 30. As shown, the cable winding unit 30 includes a cable winding mechanism 32.
And an electric motor 4 for driving the cable winding mechanism 32
2 and is fixed to the vehicle by fixing members 47 to 49. A worm gear 3 is attached to a drive gear 34 attached to a rotating shaft of a rotor of the electric motor 42.
A rotation speed adjusting gear 36 coaxial with the gear 8 meshes with the gear 8, and the worm gear 38 is rotated by driving the electric motor 42. The worm gear 38 meshes with a fan-shaped hoisting gear 40 that winds up the cable 26.
6 can be wound up or rewound.
The rotation speed of the electric motor 42 can be adjusted by changing the duty ratio of the applied voltage. When the cable 26 is wound by the hoisting gear 40, the tension of the cable 26 causes the parking brake unit 2 to rotate.
2 and 24 operate to apply a braking force to the left and right rear wheels 12 and 14.

The electronic control unit 50 is configured as a microprocessor mainly including a CPU 52, and includes a ROM 54 storing a processing program, a RAM 56 storing data temporarily, and an input / output port (not shown). Prepare. The electronic control unit 50 includes left and right rear wheels 1
The wheel speeds Vl and Vr from the wheel speed sensors 62 and 64 attached to the motors 2 and 14, the current applied to the motor 42 from an ammeter (not shown) attached to the motor 42 of the cable winding unit 30, and a panel in front of the driver's seat. An ON / OFF signal from an operation switch 66 for instructing activation and release of a parking brake, a shift position SP from a shift position sensor 71 for detecting the position of a shift lever 70, and an accelerator switch 73 for detecting depression of an accelerator pedal 72. Accelerator switch A
S, a brake switch BS from a brake switch 75 for detecting depression of the brake pedal 74, an ignition signal IG from an ignition switch 76, a cable tension T from a tension sensor 78 attached to the cable 26, and the like are input via an input port. Have been. From the electronic control unit 50, a drive signal to the electric motor 42, a display signal G to the liquid crystal panel 80 fitted in a part of a panel on the front of the driver's seat, and the like are output via an output port.

In the electric parking brake device 20 of the embodiment configured as described above, the parking brake automatic operation control for automatically operating the parking brake according to the state of the vehicle is performed. For example, it operates when the shift lever 70 is in the stop position such as “P” or “N”, the vehicle speed is substantially zero, and the brake pedal 74 is depressed to output an ON signal from the brake switch 75. Assuming that the condition is satisfied, a drive signal is output from the electronic control unit 50 to the electric motor 42 to drive the electric motor 42.

In the electric parking brake device 20 of the embodiment,
Automatic parking brake release control is also performed together with such parking brake automatic operation control. FIG. 3 is a flowchart illustrating an example of a parking brake automatic release control routine executed by the electronic control unit 50 of the electric parking brake device 20 according to the embodiment. This routine is executed every predetermined time (for example, 8 ms) when the parking brake is in the operating state.
ec).

When the parking brake automatic release control routine is executed, the CPU 52 of the electronic control unit 50
First, a process of reading the shift position SP from the shift position sensor 71, the accelerator switch AS from the accelerator switch 73, the brake switch BS from the brake switch 75, and the vehicle speed V is executed (step S1).
00). As the vehicle speed V, a value calculated by calculation from the wheel speeds Vl, Vr from the wheel speed sensors 62, 64 can be used, or a speed sensor attached to a transmission (not shown) to detect the speed of the drive shaft. A signal calculated from the signal from the second controller may be used.

Subsequently, it is determined whether or not the read vehicle speed V is equal to 0 and whether or not the shift position SP is at a position where the vehicle can travel (steps S102 and S104). When the vehicle speed V is not the value 0, that is, when the vehicle is traveling, or at a position where the shift position SP can travel, that is, “D”, “2”,
When it is not in the forward position such as "L" or the reverse position such as "R", it is determined that the control is unnecessary, and this routine is ended.

If the vehicle speed V is 0, the shift position S
When P is at a position where the vehicle can travel, it is determined whether or not the brake switch 75 is normal (step S1).
06). This determination is made when an abnormality such as disconnection or short circuit of the signal line related to the brake switch 75 is determined based on the resistance value of the switch, or when the brake switch BS is not turned on despite the driver depressing the brake pedal 74. This is performed by judging. In the embodiment, the result of such determination is stored in a predetermined address of the RAM 56, and in the process of step S106, the predetermined address of the RAM 56 is read to determine whether the brake switch 75 is abnormal.

When it is determined that the brake switch 75 is normal, it is determined whether the brake switch BS is off (step S108). When the brake switch BS is off, the condition for releasing the parking brake is satisfied. Then, the electric motor 42 is driven to release the parking brake (step S112), and this routine ends.
When the brake switch BS is ON, it is determined that there is no intention to start the vehicle, and this routine ends without releasing the parking brake. As described above, since the parking brake is released when the brake switch BS is turned off, the driving force does not suddenly act on the driving wheels, and it is possible to suppress the deterioration of the riding comfort of the occupant.

On the other hand, if it is determined in step S106 that the brake switch 75 is abnormal, it is determined whether the accelerator switch AS is on (step S1).
10) When the accelerator switch AS is ON, it is determined that the parking brake release condition is satisfied, and the electric motor 42 is driven to release the parking brake (step S11).
2) This routine ends. When the accelerator switch AS is off, it is determined that there is no intention to start the vehicle, and this routine ends without releasing the parking brake. in this way,
Even when the brake switch 75 has an abnormality, the parking brake can be released based on the ON / OFF of the accelerator switch AS.

According to the electric parking brake apparatus 20 of the embodiment described above, the parking brake is released when the brake switch BS is turned off in the position where the shift position SP can travel, so that the driving force is applied to the driving wheels. It is possible to suppress the deterioration of the ride comfort of the occupant due to the sudden action. That is, departure can be performed smoothly. Moreover, it is determined whether or not the brake switch 75 is normal. If the brake switch 75 is abnormal, the parking brake is released based on the on / off operation of the accelerator switch AS instead of the brake switch BS. It is possible to prevent the automatic release of the parking brake from being disabled due to the abnormality of 75.

In the electric parking brake device 20 of the embodiment,
The release of the parking brake is determined by the on / off signal from the brake switch 75 for detecting the depression of the brake pedal 74 and the on / off signal from the accelerator switch 73 for detecting the depression of the accelerator pedal 72. A brake pedal position sensor or an accelerator pedal 72 for detecting the amount of depression of the brake pedal 74 instead of the on / off signal
The determination of the release of the parking brake may be performed based on a position signal from an accelerator pedal position sensor that detects the amount of depression of the vehicle.

The embodiments of the present invention have been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various embodiments may be made without departing from the gist of the present invention. Of course, it can be carried out.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing the configuration of an electric parking brake device 20 according to one embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating the configuration of a cable winding unit 30;

FIG. 3 is a flowchart showing an example of a parking brake automatic release control routine executed by an electronic control unit 50 of the electric parking brake device 20 of the embodiment.

[Explanation of symbols]

12, 14 rear wheel, 20 electric parking brake device, 2
2,24 parking brake unit, 26 cables, 3
0 cable winding unit, 32 cable winding mechanism, 34 drive gear, 36 rotation speed adjusting gear, 38
Worm gear, 40 hoisting gear, 42 electric motor,
50 electronic control unit, 52 CPU, 54 RO
M, 56 RAM, 62, 64 Wheel speed sensor, 66
Operation switch, 70 shift lever, 71 shift position sensor, 72 accelerator pedal, 73 accelerator switch, 74 brake pedal, 75 brake switch, 76 ignition switch, 78 tension sensor, 80 liquid crystal panel.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takehiro Yanaka 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Toshitaka Hamada 2-1-1 Asahimachi, Kariya City, Aichi Prefecture Aisin Seiki F term in reference (reference) 3D046 BB01 BB02 CC01 CC06 EE02 HH02 HH05 HH07 HH22 HH36 MM06 MM15

Claims (5)

[Claims] 1. An electric parking brake device having a parking brake operated and released by an electric driving means, comprising: a shift position detection means for detecting a shift position; and a brake operation state detection for detecting an operation state of a service brake. Means for driving the electric vehicle so as to release the parking brake when a shift position at which the vehicle can travel is detected by the shift position detection means and a state in which the operation of the service brake is released is detected by the brake operation state detection means. Control means for controlling the means. 2. The electric parking brake device according to claim 1, further comprising: abnormality detection means for detecting abnormality of the brake operation state detection means; and accelerator operation state detection means for detecting an accelerator operation state. When the abnormality detecting means detects an abnormality in the brake operation state detecting means, the control means detects a shift position at which the vehicle can travel by the shift position detecting means, and operates the accelerator by the accelerator operation state detecting means. An electric parking brake device, which is means for controlling to release the parking brake when detecting a released state. 3. The electric parking brake device according to claim 1, further comprising: a traveling state detection unit that detects a traveling state of the vehicle, wherein the control unit stops the vehicle by the traveling state detection unit. An electric parking brake device, which is a means for performing control for releasing the parking brake when detecting that the vehicle is in a parking state. 4. A parking brake control method for releasing a parking brake that is operating when a predetermined departure operation is performed, comprising detecting that the vehicle is in a shiftable position and operating a service brake. A parking brake control method for releasing the parking brake when it is detected that the parking brake is released. 5. The parking brake is released when the operation of the service brake is not detected due to an abnormality, and when the operation of an accelerator is detected instead of detecting the release of the operation of the service brake. 4. The method for controlling a parking brake according to 4.