JP2001106046A - Electric parking brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make braking force by a parking brake more suitable. SOLUTION: Moving force Fe of a vehicle to be moved by power of an engine on the basis of the position of a shift lever is determined (S100 to S108) from the revolution Ne of the engine, braking force Fb to be obtained by pedaling a brake pedal is determined (S110, S112) on the basis of brake master cylinder pressure PB, and braking force F by a parking brake is set (S114) as a value obtained by adding a specified value Fs as braking force for stably stopping a vehicle on the level ground to the sum of the moving force Fe and the braking force Fb. The parking brake is operated (S116) by an electric motor so that braking force by the parking brake may be a value F. As a result, more suitable braking force can be made to act from 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 more particularly, to an electric parking brake device that operates a parking brake by an electric driving means.

[0002]

2. Description of the Related Art Conventionally, as this type of electric parking brake device, there has been proposed an electric parking brake device which operates a parking brake so that a braking force corresponding to the pressure of a brake master cylinder acts (for example, Japanese Patent Laid-Open No. 5-139269). Issue publication). In this device, the pulling force of the cable of the parking brake is made proportional to the pressure of the brake master cylinder, so that the braking force of the parking brake corresponds to the pressure of the brake master cylinder. And
When the pulling force of the cable exceeds a predetermined value, an off signal is output to the controller to prevent the pulling force of the cable from becoming excessive.

[0003]

However, in such an electric parking brake device, there is a case where an appropriate braking force required for the parking brake cannot be obtained. In a vehicle equipped with an automatic transmission, even when the vehicle is stopped, when the shift lever is in the traveling position, a creep force is exerted on the vehicle to move the vehicle. Therefore, in the case of a vehicle stopped on an uphill, the vehicle is stopped by the creep force and the brake braking force that is applied by the driver depressing the brake pedal, so that a braking force corresponding to the brake braking force is applied. When the parking brake is actuated, the vehicle may retreat when the brake pedal is released and the shift lever is set to the N position or the like.

[0004] An object of the present invention is to provide an electric parking brake device that makes the braking force of the parking brake more appropriate.

[0005]

Means for Solving the Problems and Their Functions and Effects The electric parking brake device of the present invention employs the following means in order to achieve the above object.

An electric parking brake device according to the present invention is an electric parking brake device which operates a parking brake by an electric driving means, and detects a braking force applied to a vehicle based on an operation of the driver. Detecting means, moving force detecting means for detecting a moving force for moving the vehicle due to the operation of the power source of the vehicle, and a braking force detected by the detected moving force and the braking force detected by the braking force detecting means. Braking force setting means for setting a braking force based on the operation of the parking brake based on the parking brake, and control means for driving and controlling the electric driving means so that the set braking force is applied by the operation of the parking brake. Make a summary.

In the electric parking brake device of the present invention,
The braking force setting means controls the vehicle based on the braking force applied to the vehicle based on the driver's operation detected by the braking force detecting means and the operation of the power source of the vehicle detected by the moving force detecting means. The braking force by operating the parking brake is set based on the moving force to be moved, and the control means drives and controls the electric driving means so that the set braking force is applied by operating the parking brake. As a result, the braking force by the parking brake can be made more appropriate.

In the electric parking brake device of the present invention, the moving force detecting means may be means for detecting the moving force based on the power output from the power source. In the electric parking brake device according to the aspect of the present invention, the power source is a power device that outputs power to a rotating shaft, and the moving force detecting unit detects the moving force based on a rotation speed of the rotating shaft. May be used.

Further, in the electric parking brake device according to the present invention, the braking force detecting means includes a brake depression amount,
The means may be a means for detecting the braking force based on at least one of an operating force applied to a brake pedal and a pressure of a brake master cylinder.

Further, in the electric parking brake device according to the present invention, the braking force setting means sets a force equal to or greater than the sum of the detected braking force and the moving force as a braking force due to the operation of the parking brake. It can be. In this case, the vehicle can be stably stopped.

[0011] In the electric parking brake device of the present invention,
Parking brake braking force detection means for detecting a braking force by the parking brake, wherein the control means controls the braking force detected by the parking brake braking force detection means to be the set braking force. It can also be. This makes it possible to more reliably set the braking force of the parking brake to the set braking force. In the electric parking brake device according to the aspect of the present invention, the parking brake braking force detecting means may be means for detecting the braking force based on a current applied to an electric driving means. In this case, the braking force by the parking brake can be detected without directly detecting the braking force.

[0012]

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 composed of a CPU 52, and has a ROM 54 storing a processing program, a RAM 56 temporarily storing data, and an input / output port (not shown). And This electronic control unit 50 includes:
Wheel speed sensors 6 attached to left and right rear wheels 12 and 14
2, 64, the wheel speeds Vl, Vr, the applied current I to the motor 42 from an ammeter (not shown) attached to the motor 42 of the cable winding unit 30, the operation and release of the parking brake arranged on the panel in front of the driver's seat. , An on / off signal SW from an operation switch 66, a shift position SP from a shift position sensor 71 for detecting the position of a shift lever 70, and an accelerator pedal 7
The accelerator pedal position AP from the accelerator pedal position sensor 73 for detecting the depression amount of the brake pedal 2, and the brake pedal position B from the brake pedal position sensor 75 for detecting the depression amount of the brake pedal 74
P, a brake master cylinder pressure PB from a hydraulic pressure sensor 77 attached to the brake master cylinder 76, and an ignition signal I from an ignition switch 78
G, the rotation speed Ne of the engine 16 from a rotation speed sensor 80 attached to the engine 16 and the like are input via an input port. Further, a drive signal or the like to the electric motor 42 is output from the electronic control unit 50 via an output port.

In the electric parking brake device 20 of the embodiment configured as described above, automatic parking brake control for automatically activating and releasing the parking brake according to the state of the vehicle is performed. The automatic operation of the parking brake is, for example, when the shift lever 70 is in the stop position of the P position or the N position, the vehicle speed is substantially zero, and
When the brake pedal 74 is depressed and the ON signal is output from the brake pedal position sensor 75, the electronic control unit 50 outputs a drive signal to the electric motor 42 to drive the electric motor 42 assuming that the operating condition is satisfied. It is. Further, the automatic release of the parking brake is performed, for example, by setting the shift lever 70 to the P position or the N position.
A drive signal is output from the electronic control unit 50 to the electric motor 42 assuming that the release condition is satisfied when the accelerator pedal 72 is depressed and the ON signal is output from the accelerator pedal position sensor 73 when the accelerator pedal 72 is depressed and the accelerator pedal 72 is depressed. The driving is performed by driving the electric motor 42.

The electric parking brake device 20 of the embodiment
In addition, in addition to the automatic parking brake control described above, when the operation switch 66 is operated, the control of the operation and release of the parking brake is performed based on the operation of the operation switch 66.

Next, the electric parking brake device 20 of the embodiment will be described.
The operation of, particularly the operation when the parking brake is operated will be described. FIG. 3 shows an electric parking brake device 20 according to the embodiment.
5 is a flowchart showing an example of a parking brake actuation control routine executed by the electronic control unit 50 in FIG. In this routine, the operation switch 66 is operated when the operating condition is satisfied in the above-described automatic parking brake control or by the operator such as a driver, and the on / off signal SW is set to O.
Executed when N is set.

When the parking brake operation routine is executed, the CPU 52 of the electronic control unit 50 first reads the shift position SP detected by the shift position sensor 71 (step S100), and shifts the shift position SP to the N position. Alternatively, a process of determining whether the position is other than the P position is performed (step S10).
2). When the shift position SP is other than the N position or the P position, the rotation speed Ne of the engine 16 detected by the rotation speed sensor 80 is read (step S104), and the automatic transmission 1 is driven by driving the engine 16 based on the read rotation speed Ne.
8, the power output to the driving wheels of the vehicle, that is, the moving force Fe for moving the vehicle is determined (Step S).
106). The moving force Fe is also called a creep force, and has a larger value as the rotational speed Ne increases. In the embodiment, the relationship between the moving force Fe and the rotation speed Ne is determined by an experiment or the like, and stored in the ROM 54 in advance as a map, and when the rotation speed Ne is given, the moving force Fe corresponding to the given rotation speed Ne is given. Is derived from the map.

On the other hand, when the shift position SP is in the N position or the P position in step S102,
A value 0 is set for the moving force Fe (step S108). This is because the power based on the engine 16 is not output to the drive wheels.

When the moving force Fe is determined in this way, the brake master cylinder pressure PB detected by the hydraulic pressure sensor 77 is read (step S110), and the braking force Fb acting by depressing the brake pedal 74 is determined. A process is performed (step S112).
In the embodiment, the relationship between the brake master cylinder pressure PB and the braking force Fb is obtained by an experiment or the like and stored in the ROM 54 in advance as a map. When the brake master cylinder pressure PB is given, the given brake master cylinder pressure PB Is derived from the map.

Then, the sum of the moving force Fe, the braking force Fb, and the predetermined value Fs is set as the braking force F by the parking brake (step S114), and the electric motor 42 is driven and controlled so that the braking force by the parking brake becomes the value F. (Step S1
16) End this routine. Here, the moving force Fe, the braking force Fb, and the predetermined value Fs assume that the direction in which the braking force Fb acts is positive. The predetermined value Fs is set as a braking force by a parking brake when the vehicle is stably stopped on level ground. The drive control of the motor 42 is controlled by the motor 4
2 shows the current I at which the braking force by the parking brake corresponds to the value F.
Is a process of driving the electric motor 42 until is applied. When the parking brake is operated so that the braking force of the parking brake increases, the electric motor 4
The current I applied to 2 increases. Therefore, this relationship is obtained by an experiment or the like, and a map
4, when the braking force F is applied, a current I corresponding to the applied braking force F is derived, and the driving of the electric motor 42 may be controlled using the current I.

FIG. 4 is an explanatory diagram exemplifying a force acting on the vehicle when the shift position SP is at the D position. When the vehicle is stopped on level ground,
As shown in (a), the moving force Fe is a forward force,
Assuming that the driver depresses the brake pedal 74 with a force sufficient to prevent the vehicle from moving forward due to the moving force Fe, the braking force Fb and the moving force Fe are balanced. In this case, the braking force F by the parking brake becomes the same value as the predetermined value Fs because the moving force Fe and the braking force Fb are canceled, and the vehicle stably stops. When the driver depresses the brake pedal 74 excessively, the braking force Fb becomes larger than the moving force Fe, so that the braking force F by the parking brake becomes larger than the predetermined value Fs. When the vehicle is stopped on an uphill, as shown in FIG. 4B, if the driver depresses the brake pedal 74 so as not to move the vehicle, the force Fn acting on the vehicle due to the gradient is reduced. On the other hand, the sum of the moving force Fe of the vehicle and the braking force Fb caused by depressing the brake pedal 74 is balanced. In this case, the braking force F by the parking brake becomes a value obtained by adding a predetermined value Fs to the force Fn due to the gradient, and the vehicle stably stops. Of course, when the driver depresses the brake pedal 74 excessively, the braking force F by the parking brake increases by an excessive amount. When the vehicle is stopped on a downhill, as shown in FIG. 4 (c), if the driver depresses the brake pedal 74 so as not to move the vehicle, the force Fn acting on the vehicle due to the gradient is calculated. The braking force Fb by depressing the brake pedal 74 is balanced with the sum of the moving force Fe of the vehicle and the vehicle. In this case, the braking force F by the parking brake becomes a value obtained by adding the predetermined value Fs to the braking force Fb by depressing the brake pedal 74, and the vehicle stably stops. Similarly,
When the driver depresses the brake pedal 74 excessively, the braking force F by the parking brake increases by an excessive amount.

When the shift lever 70 is in the N position or the P position, the braking force Fb depressed by the brake pedal 74 balances the force Fn due to the gradient. In this case, since the value 0 is set for the vehicle moving force Fe, the braking force F by the parking brake becomes a value obtained by adding the predetermined value Fs to the braking force Fb, and the vehicle stably stops.

According to the electric parking brake device 20 of the embodiment described above, an appropriate braking force according to the stopped state of the vehicle can be applied from the parking brake.
In addition, since an excessive braking force is not applied from the parking brake, the durability of the parking brake can be improved.

In the electric parking brake device 20 of the embodiment,
Although the braking force Fb is determined based on the brake master cylinder pressure PB, the braking force Fb may be determined based on the depression force, the position, and the like of the brake pedal 74.

The electric parking brake device 20 of the embodiment
In the above, the driving control of the electric motor 42 was performed by detecting the braking force by the parking brake based on the current I of the electric motor 42, but the tension of the cable 26 was detected to obtain the braking force by the parking brake. Or the drive control of the electric motor 42 may be performed by directly detecting the braking force of the parking brake.

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 scope 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 actuation control routine executed by an electronic control unit 50 in the electric parking brake device 20 of the embodiment.

FIG. 4 is an explanatory diagram exemplifying a force acting on a vehicle when a shift position SP is at a D position.

[Explanation of symbols]

12,14 rear wheel, 16 engine, 18 automatic transmission, 20 electric parking brake device, 22,24 parking brake unit, 26 cable, 30 cable winding unit, 32 cable winding mechanism, 34 drive gear, 36 rotation speed adjusting gear, 38 Worm gear, 40 hoisting gear, 42
Motor, 50 electronic control unit, 52 CPU, 54
ROM, 56 RAM, 62, 64 Wheel speed sensor,
66 operation switch, 70 shift lever, 71 shift position sensor, 72 accelerator pedal, 73 accelerator pedal position sensor, 74 brake pedal, 75 brake pedal position sensor, 76 brake master cylinder, 77 oil pressure sensor, 78 ignition switch, 80 rotation speed sensor .

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takayuki Yamamoto 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (72) Inventor Shingo 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F term (reference) 3D046 BB02 CC06 EE02 HH00 HH02 HH05 HH07 HH13 HH16 HH17 HH26 HH36 HH52 LL00

Claims (7)

[Claims] 1. An electric parking brake device which operates a parking brake by an electric driving means, comprising: a braking force detecting means for detecting a braking force applied to a vehicle based on an operation of the driver; Moving force detecting means for detecting a moving force for moving the vehicle due to the operation of the power source; and operating the parking brake based on the detected moving force and the braking force detected by the braking force detecting means. An electric parking brake device comprising: a braking force setting unit that sets a braking force according to (1); and a control unit that drives and controls the electric driving unit so that the set braking force acts by operating the parking brake. 2. The electric parking brake device according to claim 1, wherein said moving force detecting means is means for detecting said moving force based on power output from said power source. 3. The electric parking brake device according to claim 2, wherein the power source is a power device that outputs power to a rotating shaft, and the moving force detecting unit is based on a rotation speed of the rotating shaft. And an electric parking brake device for detecting the moving force. 4. The braking force detecting means according to claim 1, wherein said braking force detecting means detects said braking force based on at least one of a brake depression amount, an operating force applied to a brake pedal, and a pressure of a brake master cylinder. The electric parking brake device according to any one of the above. 5. The braking force setting unit according to claim 1, wherein the braking force setting unit sets a force equal to or greater than the sum of the detected braking force and the moving force as a braking force by operating the parking brake. Electric parking brake device. 6. The electric parking brake device according to claim 1, further comprising: a parking brake braking force detecting unit configured to detect a braking force of the parking brake, wherein the control unit detects the parking brake braking force. The electric parking brake device is means for controlling the braking force detected by the means to be the set braking force. 7. The electric parking brake device according to claim 6, wherein said parking brake braking force detecting means is means for detecting said braking force based on a current applied to an electric driving means.