JP6727705B2 - Electric parking brake device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric parking brake device that operates brake means by operating a parking brake operation switch to generate a predetermined braking force.

In general, an electric parking brake device operates a brake means such as a disk brake when a driver turns on a parking brake operation switch when the vehicle is stopped to generate a predetermined braking force to stop the vehicle. When the vehicle is held and a predetermined release condition such as turning off the parking brake operation switch or depressing the accelerator pedal is satisfied, the braking for parking till then is released.

In such an electric parking brake device, conventionally, the slope of the road surface is detected, the braking force generated by the braking means is varied according to the detected slope, and a more appropriate braking force is obtained to ensure the safety of the vehicle when the vehicle is stopped. Has been proposed (Patent Document 1).

JP-A-59-145658 (page 3, upper right column, second line-page 4, upper left column, line 12; page 5, upper right column, line 16-lower left column, line 20; see FIG. 8).

By the way, in the case where the braking force is varied according to the gradient of the road surface as described in Patent Document 1 above, it is set based on the creep force of the vehicle, the gradient of the road surface, etc. so that the vehicle can be more reliably held in the stopped state. It is generally controlled to generate a braking force in which a certain margin is added to the value.

Then, when driving a vehicle equipped with this type of electric parking brake device, for example, when the electric parking brake is activated even while waiting for a signal, the driver can operate the brake pedal, As described above, the braking force with a certain margin is generated and held in the stopped state.Therefore, when the signal changes and the vehicle is started, the parking brake operation switch is turned off or the accelerator pedal is depressed. Even if the predetermined release condition is satisfied, there is a problem that it takes time until the vehicle actually starts to start, and the driver feels uncomfortable such as dragging feeling or jumping out feeling.

The present invention is capable of releasing the electric parking brake without a feeling of discomfort when a release condition for releasing the braking for parking is satisfied, and can reliably hold the vehicle in a stopped state by a sufficient braking force when necessary. To aim.

In order to achieve the above-mentioned object, the electric parking brake device of the present invention operates the brake means by operating the parking brake switch to generate a predetermined braking force, and the brake is released when a release condition for releasing the parking brake is satisfied. the electric parking brake system Ru stops the operation of the means, the driver brake pedal, a detection means for detecting whether a steerable driving state of the accelerator pedal or handle, the operating condition is the driver by the detecting means When the driver is not in the driving state, the parking brake control means for controlling the generated braking force of the braking means to be smaller than that when the driver is not in the driving state, and when the driver is not in the driving state, The braking force generated by the braking means is set to a value in which a margin for guaranteeing more reliable braking is added to the reference braking force based on the creep force of the vehicle, the variation of the braking means, and the road surface slope, and The braking force generated by the brake means when the person is in the driving state is a value that takes into account a margin smaller than the margin when not in the driving state in order to start the vehicle with good response after the release condition is satisfied. It is set to a value that can hold the stopped state there is is characterized in Rukoto.

According to the present invention, when the detection means detects that the driver is in a driving state in which the driver can operate the brake pedal, the accelerator pedal, and the steering wheel, the parking brake control means performs Since the braking force generated by the braking means is controlled to a small level, even if the electric parking brake is operated while waiting for a signal, for example, the vehicle is kept in a stopped state with a small braking force. , If the release condition for releasing the parking brake by turning off the parking brake switch or depressing the accelerator pedal is satisfied, the parking brake will be released responsively, and the electric parking brake can be released without a feeling of discomfort. it can. On the other hand, even when the driver leaves the vehicle by parking on a slope, the vehicle can be reliably held in the stopped state by a sufficient braking force.

It is a block diagram of one embodiment of the electric parking brake device concerning the present invention. It is operation|movement explanatory drawing of FIG.

An embodiment of the electric parking brake device according to the present invention will be described in detail with reference to FIGS. 1 and 2.

The electric parking brake device 1 (hereinafter, the electric parking brake is referred to as EPB) 1 of the present embodiment is configured as shown in FIG.

As shown in FIG. 1, a master cylinder 3 is connected to a brake pedal 2, the master cylinder 3 is connected to a reservoir tank 4 in which brake fluid is stored, and a main brake section 6 is provided via a hydraulic pressure path 5. And supplies the brake fluid pressure to the main brake unit 6 according to the amount of depression of the brake pedal 2 by the driver. The reservoir tank 4 is connected to the main brake unit 6 via a hydraulic pressure path 7.

The main brake unit 6 connects the front wheel wheel cylinder of the right front wheel brake mounted on the right front wheel and the front wheel wheel cylinder of the left front wheel brake mounted on the left front wheel to the master cylinder 3 and hydraulic paths and various types. The master cylinder 3 is connected to the master cylinder 3 with a valve and a wheel cylinder for the rear wheel of the right rear wheel brake mounted on the right rear wheel 8R and a wheel cylinder for the rear wheel of the left rear wheel brake mounted on the left rear wheel 8L. The hydraulic pressure passages 9R and 9L, various valves, and the like are provided.

When the brake pedal 2 is depressed by the driver, a brake fluid pressure corresponding to the depression amount is generated in the master cylinder 3, and this brake fluid pressure is applied to the front wheel via the fluid pressure path of the main brake section 6 and the valve. Normal braking is applied to the left and right front wheel brakes and the left and right rear wheel brakes 10R by the braking force that is transmitted to each wheel cylinder of the rear wheels and is transmitted to the wheel cylinders corresponding to each wheel. ..

At this time, the brake pedal switch 11 is turned on/off depending on whether or not the brake pedal 2 is depressed, and the on/off signal of the brake pedal switch 11 is transmitted via the CAN (Controller Area Network) communication communication bus 12 to the rear side. It is input to an EPBECU (Electronic Control Unit) 13 that controls the electric parking brake (EPB), which will be described in detail. In addition, a detection signal of a G sensor 15 that detects the acceleration/deceleration of the vehicle body prevents skid of the vehicle. When input to a VSC (Vehicle Stability Control) ECU 16 for the purpose, the VSC ECU 16 derives the inclination of the vehicle body, that is, the slope of the road surface, and inputs it to the EPBECU 13 via the communication bus 12.

Further, a detection signal of the shift position sensor 17 for detecting the position of the shift lever, and an ON/OFF signal of an accelerator pedal switch 18 which is turned on/off according to the depression of the accelerator pedal are transmitted via the engine ECU 19 and the communication bus 12. An IG operation signal that is input to the EPBECU 13 and that corresponds to the operation of the ignition (IG) switch 20 is input to the EPBECU 13 via the communication bus 12 to detect that the seatbelt of the driver's seat is worn. The detection signal is input to the EPBECU 13 via the communication bus 12.

Then, the EPBECU 13 controls the EPB actuator 23 based on the ON operation of the EPB switch 22 arranged on the instrument panel or the like by the driver to automatically generate a predetermined braking force on the left and right rear wheel brakes 10R and 10L. Apply the parking brake. Here, the EPB actuator 23 and the left and right rear wheel brakes 10R and 10L correspond to the braking means in the present invention.

The basic configuration of the parking brake by the EPBECU 13 is a well-known electric parking brake technology applied, in which an EPB motor (not shown) is driven by an ON operation of an EPB switch 22 which is a parking brake switch, and an EPB actuator 23. The output shaft of the EPB motor constituting the motor rotates in one direction, and the rotation of this output shaft pulls the cable 24 with a predetermined tension to generate a predetermined braking force on the brakes 10R and 10L for the left and right rear wheels. Has become.

At this time, the braking force for the parking brakes by the left and right rear wheel brakes 10R and 10L is set so that the vehicle can be parked without slipping when the driver leaves the vehicle by parking on a slope. A margin (usually 30% of the standard braking force) is added to the standard braking force based on the creep force of the vehicle, the variations of the left and right rear wheels 10R and 10L, and the road surface gradient to ensure more reliable braking. Is set so that the braking force corresponds to the road surface gradient as shown by the solid line in FIG. 2, for example. The horizontal axis of FIG. 2 is the road surface gradient, "+" represents an uphill slope, and "-" represents a downhill slope.

By the way, when the EPB device 1 having such a configuration is operated while waiting for a signal, for example, the driver can always operate the brake pedal. Therefore, the driver parks on a slope and leaves the vehicle. Since it is not necessary to generate a large braking force assuming a situation, a feature of the present invention is that the EPBECU 13 performs control to reduce the braking force when the driver is in the driving state than when the driver is not in the driving state.

That is, when the seatbelt switch 21 detects that the driver is wearing the seatbelt and the shift position sensor 17 detects the D range, the EPBECU 13 allows the driver to operate the brake pedal, the accelerator pedal, and the steering wheel. Is detected, the seat belt switch 21 detects that the driver's seat belt is not worn, the shift position sensor 17 detects the P range, the brake pedal switch 11 detects that the brake pedal is off, and the accelerator pedal is detected. When the switch 18 detects that the accelerator pedal is off, it is detected that the driver is not in a driving state and has exited the vehicle. The detection process of the driving state of the driver by the EPBECU 13 corresponds to the detection means in the present invention.

Then, when the EPBECU 13 determines that the driver is in a driving state, the braking force for the parking brake by the left and right rear wheel brakes 10R and 10L is the creep force of the vehicle and the left and right rear wheel brakes 10R and 10L. 2 and the reference braking force based on the road surface gradient, for example, with a margin of 10% taken into consideration, the braking force is controlled to be small as indicated by the one-dot chain line in FIG. Specifically, when the vehicle is in the operating state, the EPBECU 13 controls the pulling force of the EPB motor of the EPB actuator 23 to be smaller and the generated braking force of the left and right rear brakes 10R and 10L to be smaller than when the vehicle is not in the operating state. It

As described above, the switching process of the braking force of the EPB ECU 13 during the parking brake of the EPB actuator 23 and the left and right rear brakes 10R and 10L corresponds to the parking brake control means in the present invention.

In this way, when the EPBECU 13 detects that the driver is in the driving state, the pulling force of the cable 24 by the EPB motor of the EPB actuator 23 is made smaller than when the driver is not in the driving state, and the parking brake is reduced. By controlling the braking force generated by the left and right rear wheel brakes 10R and 10L to a small value, when the electric parking brake is operated, for example, when waiting for a signal, when the signal changes and the vehicle starts moving, the EPB switch 22 If the release condition for releasing the parking brake by turning off the switch or switching the shift lever to the D range and depressing the accelerator pedal is satisfied, the parking brake is released in a responsive manner, and the dragging and popping-out feeling as in the past is felt. Is suppressed. Further, when it is detected that the driver gets off the vehicle after stopping by the EPB brake and the driver is not in the driving state, the pulling force of the cable 24 by the EPB motor of the EPB actuator 23 becomes large, and the brake 10R for the left and right rear wheels at the time of parking brake. , 10L, the braking force is largely switched, and the braking force is controlled to have a large margin. Therefore, even when the vehicle is parked on a slope or the like, the vehicle is held in a stopped state with sufficient braking force.

Therefore, according to the above-described embodiment, when the EPBECU 13 detects that the driver is in a driving state in which the driver can operate the brake pedal, the accelerator pedal, and the steering wheel, the EPBECU 13 is compared to when the driver is not in the driving state. As a result, the braking force generated by the brake actuator 23 and the brakes 10R, 10L for the left and right rear wheels is switched to a small value. Therefore, even when the electric parking brake is operated while waiting for a signal, the vehicle is held in a stopped state with a small braking force. Therefore, if the parking brake operation switch is turned off or the accelerator pedal is depressed to release the parking brake when the signal changes and the vehicle is started, the parking brake is released with good response. Therefore, the electric parking brake can be released without feeling discomfort such as dragging or popping out.

Further, when the driver leaves the vehicle while parked on a slope, as described above, the braking force generated by the brakes 10R and 10L for the left and right rear wheels is largely switched during parking braking to ensure the vehicle with sufficient braking force. It can be held in a stopped state.

The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.

For example, in the above-described embodiment, a case has been described in which the EPBECU 13 sets the braking force generated during parking brake so as to change according to the road surface gradient by the G sensor 15, as shown in FIG. As indicated by the broken line and the chain double-dashed line, it may be controlled to be constant regardless of the road surface gradient. Also in this case, the EPBECU 13 switches the braking force indicated by the broken line or the chain double-dashed line in FIG. 2 depending on whether or not the driver is in the driving state.

In addition, in the above-described embodiment, the braking force generated during parking braking when the driver is not in a driving state is set to a value obtained by adding a 30% margin to the reference braking force, and parking is performed when the driver is in a driving state. Although the braking force generated at the time of braking has been described as a value obtained by adding a 10% margin to the reference braking force, these margins are not limited to the above 30% and 10%.

1... EPB device (electric parking brake device)
10R, 10L... Rear wheel brake (brake means)
13... EPBECU (brake means, detection means, parking brake control means)
22... EPB switch (parking brake switch)
23... EPB actuator (brake means)

Claims (1)

By operating the brake means to generate a predetermined braking force by the operation of the parking brake switch, the establishment of releasing condition for releasing the parking brake in the electric parking brake system Ru stops the operation of the brake means,
Detection means for detecting whether or not the driver is in a driving state in which the brake pedal, the accelerator pedal and the steering wheel can be operated,
When it is detected by the detection means that the driver is in the driving state, a parking brake control means for controlling the generated braking force of the braking means to be smaller than when the driver is not in the driving state ,
The braking force generated by the braking means when the driver is not in the driving state is based on the creep force of the vehicle, the variation of the braking means, and the reference braking force based on the road surface gradient in order to ensure more reliable braking. Is set to a value that takes into account the margin of
The braking force generated by the braking means when the driver is in the driving state takes into account a margin smaller than the margin when the driver is not in the driving state in order to start the vehicle with good response after the release condition is satisfied. electric parking brake system according to claim Rukoto is set to a value capable of holding the stop state a value.

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