JP2001106060A - Electric parking brake device - Google Patents

Abstract

(57) [Summary] [Problem] To detect an abnormality of a cable of a parking brake. SOLUTION: When a parking brake is operated, a current I applied to a motor used for a mechanism for winding up a cable of a parking brake is detected to estimate an output load F of the motor larger than a threshold F1 (S100, S10
2), a warning threshold f1 (F) for the elongation of the cable derived based on the output load F in which the cable stroke S is estimated, and a threshold f for the ineffectiveness of the parking brake.
2 (F) (S110, S112), and based on the deviation of the relationship between the output load F and the cable stroke S due to the occurrence of the elongation of the cable, the normality of the cable, the elongation alarm, and the abnormality of the effectiveness are determined. As a result, the ineffectiveness of the parking brake can be detected as an abnormality, and the length of the cable can be adjusted by an extension warning before the ineffectiveness of 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 having electric hoisting means capable of operating a parking brake by winding a cable of the parking brake.

[0002]

2. Description of the Related Art Conventionally, as this kind of electric parking brake device, a parking brake is actuated by rotating a pulley by a motor to wind up a cable of the parking brake and to reverse the cable to release the parking brake. (For example, Japanese Patent Application Laid-Open No. S59-143748).
And JP-A-61-108038).

[0003]

However, in these electric parking brake devices, it may be determined that the parking brake has been actuated even when the cable of the parking brake is cut or extended.

[0004] As one method for solving at least a part of such a problem, the applicant has disclosed an electric motor which detects disconnection of a parking brake cable as an abnormality when the operating force of the parking brake does not exceed a predetermined value within a predetermined time. A parking brake device has been proposed (Japanese Utility Model Publication No. 5-33432).

[0005] An object of the electric parking brake device of the present invention is to detect an abnormality of a parking brake. Another object of the electric parking brake device of the present invention is to detect an abnormality of a parking brake so as not to affect driving and a state of a vehicle.

[0006]

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 at least a part of the above object.

[0007] The first electric parking brake device of the present invention comprises:
What is claimed is: 1. An electric parking brake device having an electric hoisting device capable of operating a parking brake by winding up a cable of a parking brake, wherein the electric hoisting force is detected by the electric hoisting device. Winding amount detecting means for detecting the winding amount of the cable, and abnormality detecting means for detecting an abnormality of the parking brake based on the detected winding amount and the winding force detected by the winding force detecting means. The point is to prepare.

In the first electric parking brake device according to the present invention, the abnormality detecting means is wound by the electric hoisting means detected by the hoisting force detecting means and the electric hoisting means detected by the winding amount detecting means. An abnormality of the parking brake is detected based on the amount of winding of the parking brake cable. The reason that the abnormality of the parking brake can be detected on the basis of the hoisting force and the hoisting amount is based on the fact that this relationship relates to elongation, breakage, disconnection, etc. of the cable. According to the first electric parking brake device of the present invention, an abnormality of the parking brake can be detected.

In the first electric parking brake device of the present invention, the hoisting force detecting means may be means for detecting the hoisting force based on the electric power supplied to the electric hoisting means. . In this case, the hoisting force can be detected without directly detecting the hoisting force. Here, the “power” includes, for example, a relationship between a current value and time supplied to the electric hoisting means, a relationship between voltage value and time, a relationship between current value and voltage value, a current value at a certain time and a certain time. And a value corresponding to the electric power calculated based on the voltage value in.

Further, in the first electric parking brake device according to the present invention, the electric hoist has a hoist for winding the cable by rotation, and the hoist detecting means detects the rotation of the hoist of the electric hoist. It may be a means for detecting the amount of hoisting based on this. In this way, the amount of winding can be detected based on the rotation of the winding unit.

Further, in the first electric parking brake device of the present invention, the abnormality detecting means detects abnormality based on the detected change amount of the hoisting force and the detected change amount of the hoisting amount. May be used. In this way, an abnormality can be detected regardless of whether the parking brake is in the operating state or the releasing state.

Alternatively, in the first electric parking brake device according to the present invention, when the parking brake is not operated, the abnormality detecting means may control the parking brake to be less than a predetermined braking force by the winding by the electric winding means. The electric hoist may be driven and controlled within a range until the power is applied to detect the abnormality. By doing so, it is possible to detect an abnormality without significantly affecting the state of the vehicle. here,
The “predetermined braking force” may use a value obtained in advance by an experiment or the like, or may change the braking force generated based on speed, temperature, or the like based on speed, temperature, or the like.

Further, in the first electric parking brake device of the present invention, when the parking brake is operating, the abnormality detecting means increases the braking force of the parking brake by winding up or rewinding by the electric winding up means. The electric hoist may be driven and controlled within a range that does not change by a predetermined braking force or more to detect the abnormality. By doing so, it is possible to detect an abnormality without significantly affecting the state of the vehicle. In addition,
The “predetermined braking force” has the same meaning as described above.

In the first electric parking brake device according to the present invention, in which the abnormality is detected with the drive control of the electric hoisting means, the abnormality detecting means sets the electric hoisting means to operate or release the parking brake. It may be a means for detecting abnormality by driving at a speed lower than the driving speed at that time. With this configuration, it is possible to reduce the operation noise generated when the electric hoist is driven and controlled to detect an abnormality.

[0015] The second electric parking brake device of the present invention comprises:
What is claimed is: 1. An electric parking brake device comprising an electric hoisting device capable of operating a parking brake by winding up a cable of a parking brake, comprising: a tension detecting device for detecting a tension of the cable of the parking brake; The gist of the present invention is to include an abnormality detecting means for detecting an abnormality of the parking brake based on a change in the tension of the cable detected by the tension detecting means at the time of winding or rewinding.

In the second electric parking brake device according to the present invention, the abnormality detecting means detects the change in the tension of the cable of the parking brake detected by the tension detecting means when the electric hoisting means winds or unwinds the cable. The abnormality of the parking brake is detected on the basis of the parking brake. An abnormality can be determined based on a change in cable tension based on the fact that winding or rewinding the cable directly affects the tension of the cable, and if an abnormality occurs, the effect of the change will be different. . According to such an electric parking brake device of the present invention, an abnormality of the parking brake can be detected.

In the second electric parking brake device of the present invention, the tension detecting means may be means for detecting the tension based on electric power supplied to the electric hoisting means. In this case, the cable tension can be detected without directly detecting the cable tension.

In the first or second electric parking brake device according to the present invention, there is provided a brake pedal depression detecting means for detecting that a brake pedal is depressed, and the abnormality detecting means is provided with the brake pedal depression detecting means. Accordingly, the abnormality detection unit may detect the abnormality while detecting that the brake pedal is being depressed.

Further, in the first or second electric parking brake device of the present invention, the abnormality detecting means may be means for detecting an abnormality in elongation of the cable.

Further, the first or second electric parking brake device according to the present invention may be provided with an output means for outputting the abnormality when the abnormality is detected by the abnormality detecting means. This allows the driver or the like to quickly recognize the abnormality.

[0021]

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.

The length of the cable 26 is fixed to a length adjusting member 27 by a bolt 28 so as to be adjustable.
That is, the cable 2 is rotated by rotating the bolt 28.
By adjusting the length between the six ends and the bolt 28, the length of the cable 26 can be adjusted as a result.

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.
A rotation angle sensor 60 that detects the rotation angle θ of the winding gear 40 is attached to the rotation shaft of the winding gear 40. The rotation speed of the electric motor 42 can be adjusted by changing the duty ratio of the applied voltage. The cable 26 is connected to the hoisting gear 40
When it is wound up, the parking brake units 22 and 24 are operated by the tension, and a braking force is applied 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:
The rotation angle θ from the rotation angle sensor 60 attached to the rotating shaft of the hoisting gear 40 and the wheel speeds Vl, V from the wheel speed sensors 62, 64 attached to the left and right rear wheels 12,14.
r, the motor 42 detected by the current sensor 61 attached to the motor 42 of the cable winding unit 30
Current I to the driver, an on / off signal SW from an operation switch 66 arranged on a panel in front of the driver's seat, and 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; An accelerator pedal position AP from an accelerator pedal position sensor 73 that detects the amount of depression of an accelerator pedal 72, a brake pedal position BP from a brake pedal position sensor 75 that detects the amount of depression of a brake pedal 74, and an ignition signal IG from an ignition switch 76 Is input via the input port. 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, automatic parking brake control for automatically activating and releasing the parking brake in accordance with 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.

In addition to the automatic parking brake control, when the operation switch 66 is operated, the operation of the parking brake is controlled based on the operation of the operation switch 66.

Next, the electric parking brake device 20 of the embodiment will be described.
Will be described, in particular, the operation when detecting an abnormality of the cable 26. FIG. 3 is a flowchart illustrating an example of a cable abnormality determination processing routine executed by the electronic control unit 50 in the electric parking brake device 20 according to the embodiment. This routine is executed together with the operation of the parking brake when the parking brake is automatically operated in the automatic parking brake control or when the operation of the operation switch 66 is performed.

When the cable abnormality determination routine is executed, the CPU 52 of the electronic control unit 50 first reads the current I applied to the motor 42 detected by the current sensor 61 (step S100). A process of estimating the output load F that has been output is executed (step S102). Here, the output load F of the electric motor 42 can be estimated from the electric current I applied to the electric motor 42 because the output load F is the electric current I applied to the electric motor 42.
It is based on changing with the change of. In the embodiment, the relationship between the current I and the output load F is obtained by an experiment or the like and stored in the ROM 54 in advance as a map. When the current I is given, the output load F corresponding to the current I is obtained from this map.
Is derived.

The output load F thus estimated is equal to the threshold value F1.
Waiting for the above (step S104), the rotation angle θ detected by the rotation angle sensor 60 is read (step S106), and the read rotation angle θ is taken up by the hoist gear 40.
Is converted to the length of the cable 26 (hereinafter referred to as cable stroke S) (step S
108). Here, the threshold value F1 is set as an appropriate value of the output load F when determining the length of the cable 26, and it is preferable to use a value smaller than a normally used output load.

Then, the converted cable stroke S is converted into a threshold value f1 (F) and a threshold value f derived from the output load F.
2 (F) (steps S110 and S112), and when the cable stroke S is smaller than the threshold value f2 (F), it is determined that the length of the cable 26 is normal (step S11).
4), when the cable stroke S is equal to or greater than the threshold value f2 (F) and less than the threshold value f1 (F), the cable 26 is slightly elongated, and an extension warning that prompts adjustment is output (step S11).
6) If the cable stroke S is equal to or greater than the threshold value f1 (F), it is determined that the parking brake is not sufficiently effective, and a poor performance is output (step S118), and this routine ends. FIG. 4 shows an example of the relationship between the normal cable stroke S or the extended cable stroke S and the output load F. In the figure, a straight line SF1 shows the relationship between the cable stroke S and the output load F as a normal initial state, and the straight line SF1
2 shows a relationship between the cable stroke S as a threshold value for prompting the adjustment of the length of the cable 26 and the output load F, and a straight line S
F3 indicates the relationship between the cable stroke S and the output load F as a threshold for determining that the effectiveness of the parking brake is insufficient. Threshold value f1 in cable abnormality determination processing routine
(F) is a value obtained by comparing the output load F when the output load F exceeds the threshold value F1 with reference to the relationship of the straight line SF3 in FIG. 4. When the output load F matches the threshold value F1, the value S3 is obtained.
(See FIG. 4). Also, the threshold value f2 (F)
Is a value obtained by comparing the output load F when the output load F exceeds the threshold value F1 with reference to the relationship of a straight line SF2 in FIG.
When the output load F matches the threshold value F1, the value S2 (FIG. 4)
Reference). That is, the output load F is equal to the threshold value F1.
When the cable stroke S is less than the value S2, it is determined that the parking brake can be normally applied, and when the cable stroke S is equal to or more than the value S2, the value S3 is determined.
When the value is less than the predetermined value, it is determined that the parking brake can be activated effectively, but it is necessary to adjust the extension of the cable 26. When the cable stroke S is equal to or more than the value S3, the parking brake cannot be activated effectively. Is determined. When it is determined that it is necessary to adjust the extension of the cable 26 or when it is determined that the parking brake cannot be effectively activated, an output such as displaying an alarm on the liquid crystal panel 80 is provided. Do it.

According to the electric parking brake device 20 of the embodiment for executing the above-described cable abnormality determination processing routine, it is possible to detect an abnormality due to the extension of the cable 26 of the parking brake. In addition, before the state in which the parking brake cannot be activated effectively can be activated, the state in which the extension of the cable 26 needs to be adjusted is determined and output as an alarm before the abnormality is output. The elongation of 26 can be adjusted.

In the cable abnormality determination processing routine executed by the electric parking brake device 20 of the embodiment, the current I applied to the electric motor 42 is detected and the output load F of the electric motor 42 is estimated. Applied current I
And the voltage may be detected to estimate the output load F based on the power. Of course, the output load F of the electric motor 42
May be directly detected.

In the cable abnormality determination processing routine executed by the electric parking brake device 20 according to the embodiment, the rotation angle θ of the hoisting gear 40 is detected, and the rotation angle θ is determined by the cable stroke S.
However, the cable stroke S may be directly detected.

In the electric parking brake device 20 of the embodiment,
When the parking brake is automatically operated in the automatic parking brake control and when the parking brake is operated by operating the operation switch 66, the cable abnormality determination processing routine illustrated in FIG. 3 is executed together with the parking brake operation. However, when the parking brake is automatically operated by the automatic parking brake control or when the parking brake is operated by operating the operation switch 66, the parking brake is operated together with the operation of the parking brake. The cable abnormality determination processing routine may be executed.

In the electric parking brake device 20 of the embodiment,
When the automatic operation of the parking brake in the automatic parking brake control described above is performed or when the parking switch is operated by operating the operation switch 66, the abnormality of the extension of the cable 26 is determined together with the operation of the parking brake. In addition, an abnormality relating to the parking brake cable 26 is also determined as one of the initial checks at the time of starting the vehicle. FIG. 5 is a flowchart illustrating an example of a start-time cable abnormality determination processing routine executed by the electronic control unit 50 when the vehicle is started. This routine is executed in parallel with the other initial checks when the ignition signal IG from the ignition switch 76 is turned on.

When the start-time cable abnormality determination processing routine is executed, the CPU 52 of the electronic control unit 50 first executes processing for reading the brake pedal position BP detected by the brake pedal position sensor 75 (step S120). When it is determined that the brake pedal position BP is ON, that is, the brake pedal 74 is depressed (step S122), a process of reading the shift position SP detected by the shift position sensor 71 is executed (step S12).
4). Then, the shift lever 70 is shifted from the P position to the R position.
The operation waits for operation to the position, the N position, or the D position (step S126).

When the brake pedal 74 is depressed and the shift lever 70 is operated, it is determined whether or not the current parking brake state is an operation state (step S128). The abnormality of the parking brake cable 26 is determined by the determination process (step S130). When the parking brake cable 26 is not in the operating state, that is, in the release state, the abnormality of the parking brake cable 26 is determined by the release state abnormality determination process illustrated in FIG. Step S1
32), the determination is output (step S134), and this routine ends. The output of the determination is performed by displaying the determination result on the liquid crystal panel 80, that is, by displaying, for example, "abnormal parking cable".

When it is determined in step S128 that the vehicle is in the operating state and the operation state abnormality determining process illustrated in FIG. 6 is executed, the CPU 52 of the electronic control unit 50 firstly controls the hoisting gear detected by the rotation angle sensor 60. The rotation angle θ of the motor 40 is read (step S140), the read rotation angle θ is set to an initial value θs (step S142), and a process of driving the electric motor 42 in the slow reverse rotation is executed (step S144). The slow reverse drive of the electric motor 42 is performed by making the duty ratio of the voltage applied to the electric motor 42 smaller than a normal ratio. By controlling in this manner, the electric motor 42 is rotated slowly and the cable 26 is rotated.
Is performed.

Next, the current I applied to the motor 42 detected by the current sensor 61 and the rotation angle θ of the hoisting gear 40 are read (step S146), and the cable stroke S is converted from the read rotation angle θ (step S146). Step S
148), the converted cable stroke S and current I are sequentially stored in a predetermined area of the RAM 56 (step S1).
50). Then, the rotation angle θ is changed from the initial value θs to a predetermined value Δθ.
Is compared with the value obtained by subtracting (step S152), and steps S146 to S152 are performed until the rotation angle θ becomes smaller than this value.
Is repeated. Here, the predetermined value Δθ is a hoisting gear 40 necessary to confirm that the relationship between the change in the current I and the cable stroke S is changing stably and linearly.
Is set as the rotation angle. FIG.
2 shows an example of the relationship between the current I applied to the cable 2 and the cable stroke S. As shown, a change in the cable stroke S exhibits a hysteresis with respect to a change in the current I applied to the electric motor 42. The predetermined value Δθ is set in order to accurately check the relationship between the current I and the cable stroke S in a state where the hysteresis does not affect.

When the read rotation angle θ becomes equal to or less than the value obtained by subtracting the predetermined value Δθ from the initial value θs, the motor 42 is driven to perform slow forward rotation to return to the original operating state (step S154). In parallel with this, a process of determining an abnormality of the cable 26 (steps S154 to S162) is executed. That is, first, a process of calculating the differential value dI / dS is executed (step S156). In the embodiment, the cable strokes S sequentially stored in step S150 are stored.
And the last value Sn, In of the current I and the previously stored value Sn-1, In-1 as the ratio of the respective deviations.

Then, the absolute value of the calculated differential value dI / dS is compared with the threshold value R1 and the threshold value R2 (step S15).
8), the absolute value of the differential value dI / dS is equal to the threshold R1 and the threshold R2
When the differential value dI / dS is out of this range, it is determined to be abnormal (step S16).
2). FIG. 9 shows an example of the relationship between the current I applied to the electric motor 42 and the cable stroke S and the area of the abnormality. The curve shown as “Normal IS” in FIG.
4 shows the relationship between the current I applied to the electric motor 42 and the cable stroke S when the cable 26 is in a normal state described with reference to FIG. The illustration of the hysteresis is omitted. As shown in the figure, the relationship between the current I applied to the electric motor 42 and the cable stroke S when the cable 26 is in a normal state shows a substantially linear relationship in a certain operation region, and the inclination thereof is substantially constant. If the inclination is shifted in the lower direction, the cable 26 is often loosened, cut or disconnected, and if it is shifted to the higher inclination side, the cable 26 bites and is fixed to any member. It can be understood from experiments and past empirical rules that the locked state is often set. The threshold value R1 and the threshold value R2 in the embodiment are set as such a low-side threshold value and a high-side threshold value, and the values are determined by experiments using the electric motor 42, the parking brake units 22, 24, and the like. .

FIG. 10 shows an example of the operation of the electric motor 42, the change in the cable tension T, and the change in the cable stroke S in the operation state abnormality determination processing. As shown
At time t1, the ignition switch 76 is turned on, and the slow reverse drive of the electric motor 42 is started. This electric motor 4
2, the cable tension T decreases, but the cable stroke S does not change until time t2 due to hysteresis. At time t3 when the deviation of the cable stroke S from the initial value becomes ΔS, that is, when the deviation of the rotation angle θ from the initial value θs becomes a predetermined value Δθ, the electric motor 42 is controlled to the slow forward drive to return to the original operating state. It is. At this time, the differential value dI / dS is calculated, and the calculated differential value dI / dS is calculated.
dS is compared with the threshold value R1 and the threshold value R2 to determine the abnormality of the cable 26. When returning to the original operating state, the cable tension T changes at the same time as the forward rotation of the electric motor 42, but the cable stroke S does not change until time t4 due to hysteresis. As described above, the abnormality of the cable 26 is determined when the current I applied to the electric motor 42 and the cable stroke S have a stable and linear relationship, so that it is not necessary to reduce the cable tension T more than necessary. Therefore, the abnormality of the cable 26 can be detected within a range that does not affect the operation state of the parking brake.

When it is determined in step S128 in the cable abnormality determination processing routine at the time of starting shown in FIG. 5 that the operation state is not the operation state and the release state abnormality determination processing illustrated in FIG. 7 is performed, the CPU 52 of the electronic control unit 50 firstly executes the motor operation. Then, a process of driving the slow forward rotation of the shutter 42 is performed (step S170). The slow forward driving of the electric motor 42 is controlled by the electric motor 4.
The operation is performed with the duty ratio of the voltage applied to 2 smaller than the normal forward drive ratio.

Subsequently, the current I applied to the electric motor 42 and the rotation angle θ of the hoist gear 40 are read (step S).
172), the cable stroke S is converted from the rotation angle θ of the hoisting gear 40 (step S174), and a process of sequentially storing the converted cable stroke S and the current I in a predetermined area of the RAM 56 is performed (step S176).
Then, the current I is compared with the threshold value Iref (step S1).
78), the processes of steps S172 to S178 are repeated until the current I becomes equal to or larger than the threshold value Iref. Here, the threshold value I
ref is set to a value slightly higher than the lower limit of the current at which the current I applied to the electric motor 42 and the cable stroke S exhibit a stable and linear relationship (see FIG. 8).

When the current I becomes equal to or greater than the threshold value Iref, the motor 42 is driven in the slow reverse rotation to return to the original release state (step S180), and, in parallel with this, the abnormality of the cable 26 is determined (step S180). Step S182
To S188). This processing is performed in steps S156 to S1 in the operation state abnormality determination processing routine of FIG.
This is the same as the processing of 62. Therefore, a detailed description of this processing is omitted.

FIG. 11 shows an example of the operation of the electric motor 42, the change in the cable tension T, and the change in the cable stroke S in the release state abnormality determination processing. As shown
At time t1, the ignition switch 76 is turned ON, and the slow forward drive of the electric motor 42 is started. This electric motor 4
2, the cable stroke S changes, but the cable tension T hardly changes until time t2 when the so-called rattling is completed. Current I applied to motor 42
Becomes a threshold value Iref and the cable tension T becomes the value Tref at time t3, the electric motor 42 is controlled to the slow reverse rotation drive to return to the original release state. At this time, the differential value dI /
dS is calculated, and the calculated differential value dI / dS is set to a threshold value R.
The abnormality of the cable 26 is determined by comparing 1 with the threshold value R2. When returning to the original release state, the cable tension T
Changes at the same time as the forward rotation of the motor 42, but the cable stroke S does not change until time t4 due to hysteresis. Also, during the time t5 to the time t6 when the cable tension T does not change to substantially zero, the cable stroke S
Keep changing due to hysteresis. As described above, when the current I applied to the electric motor 42 and the cable stroke S are stably and linearly related, the abnormality of the cable 26 is determined, so that the cable tension T more than necessary is not generated. Therefore, the abnormality of the cable 26 can be detected within a range that does not significantly affect the release state of the parking brake.

The electric parking brake device 20 according to the embodiment for executing the above-described cable abnormality determination processing routine at the time of starting is described.
According to the above, the cable 26 based on the amount of change in the current I applied to the motor 42 and the amount of change in the cable stroke S
Can be determined. Moreover, when the parking brake is in the operating state, the abnormality of the cable 26 can be determined without significantly affecting the operating state of the parking brake. Further, when the parking brake is in the released state, the abnormality of the cable 26 can be determined without greatly affecting the released state of the parking brake. Further, the electric motor 4 for determining the abnormality of the cable 26
Since the second driving speed is set to be lower than the operating speed at the time of normal operation or at the time of release, the influence on the state of the parking brake when the abnormality is determined can be minimized. Further, since the abnormality of the cable 26 is determined while the brake pedal 74 is being depressed, the vehicle does not move during the determination.

In the starting cable abnormality determination processing routine executed by the electric parking brake device 20 of the embodiment, the abnormality of the cable 26 is determined based on the amount of change in the current I applied to the electric motor 42 and the amount of change in the cable stroke S. Although it has been determined, since the current I applied to the electric motor 42 and the output load F of the electric motor 42 have a predetermined relationship as described above, the output load F of the electric motor 42 is detected directly or indirectly, and the output load F The abnormality of the cable 26 may be determined based on the change amount and the change amount of the cable stroke S.
Further, since the output load F of the electric motor 42 is the cable tension T of the cable 26, the cable tension T is detected directly or indirectly, and the cable tension of the cable 26 is determined based on the change amount of the cable tension T and the change amount of the cable stroke S. The abnormality may be determined.

The electric parking brake device 20 of the embodiment
In the startup cable abnormality determination processing routine executed by
When the parking brake is operating, the operation state abnormality determination processing is performed to determine the abnormality of the cable 26. When the parking brake is released, the release state abnormality determination processing is performed to determine the abnormality of the cable 26. When the brake is operating, the operating state abnormality determination process is performed to determine the abnormality of the cable 26. However, when the parking brake is released, the abnormality of the cable 26 is not determined. Is released, the release state abnormality determination process is performed to determine the abnormality of the cable 26. However, when the parking brake is operating, the determination of the abnormality of the cable 26 may not be performed.

Further, the electric parking brake device 2 of the embodiment
In the start-up cable abnormality determination routine executed by 0, the electric motor 42 is slow-driven when the abnormality of the cable 26 is determined. However, the motor 42 may be driven at a normal driving speed. The drive may be performed at the normal drive speed only when returning to the state.

In the electric parking brake device 20 of the embodiment,
FIG. 5 also shows the cable abnormality determination processing routine illustrated in FIG.
In the start-up cable abnormality determination processing routine exemplified in
Although the output of the determination is a display output to the liquid crystal panel 80, a speaker may be provided, and the output of the determination may be performed by audio output from the speaker.

In the electric parking brake device 20 of the embodiment,
Although the cable abnormality determination processing routine illustrated in FIG. 3 and the cable abnormality determination processing routine at start-up illustrated in FIG. 5 are both executed, it is also possible to execute only one of them.

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 illustrating an example of a first operation switch abnormality detection processing routine executed by an electronic control unit 50 in the electric parking brake device 20 of the embodiment.

FIG. 4 is an explanatory diagram showing an example of a relationship between a normal cable stroke S or an extended cable stroke S and an output load F;

FIG. 5 is a flowchart illustrating an example of a start-time cable abnormality determination processing routine executed by the electronic control unit 50 in the electric parking brake device 20 according to the embodiment when the vehicle is started.

FIG. 6 is a flowchart illustrating an example of an operation state abnormality determination processing routine executed by the electronic control unit 50 in the electric parking brake device 20 of the embodiment.

FIG. 7 is a flowchart illustrating an example of a release state abnormality determination processing routine executed by the electronic control unit 50 in the electric parking brake device 20 of the embodiment.

FIG. 8 is an explanatory diagram showing an example of a relationship between a current I applied to an electric motor 42 and a cable stroke S.

FIG. 9 is an explanatory diagram showing an example of a relationship between a current I applied to an electric motor 42 and a cable stroke S and an abnormal region thereof.

FIG. 10 is an explanatory diagram showing an example of the operation of the electric motor 42, a change in the cable tension T, and a change in the cable stroke S during the operation state abnormality determination process.

FIG. 11 is an explanatory diagram showing an example of an operation of the electric motor 42, a change in the cable tension T, and a change in the cable stroke S in the release state abnormality determination process.

[Explanation of symbols]

12, 14 rear wheel, 20 electric parking brake device, 2
2,24 parking brake unit, 26 cables, 2
7 Length adjusting member, 28 volts, 30 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 ROM, 56 RAM, 6
0 rotation angle sensor, 61 current sensor, 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 Ignition switch, 80 LCD panel.

 ──────────────────────────────────────────────────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 BB01 CC01 EE02 HH03 MM01 MM08 3D049 BB01 CC01 HH40 HH47 HH48 HH51 RR08 RR10 RR11

Claims (12)

[Claims] 1. An electric parking brake device having electric hoisting means capable of operating a parking brake by winding up a cable of a parking brake, wherein the hoisting force detecting means for detecting a hoisting force by the electric hoisting means; A winding amount detecting means for detecting a winding amount of the cable wound by the winding means; and detecting an abnormality of the parking brake based on the detected winding amount and the winding force detected by the winding force detecting means. An electric parking brake device comprising an abnormality detection unit. 2. The electric parking brake device according to claim 1, wherein the hoisting force detecting means is means for detecting the hoisting force based on electric power supplied to the electric hoisting means. 3. The electric parking brake device according to claim 1, wherein the electric hoist has a hoist that winds up the cable by rotation, and the hoisting amount detecting means is a part of the electric hoist. An electric parking brake device, which is means for detecting the amount of hoisting based on the rotation of the hoisting portion. 4. The abnormality detecting means according to claim 1, wherein the abnormality detecting means detects an abnormality based on the detected change in the hoisting force and the detected change in the hoisting amount.
The electric parking brake device according to any one of the above. 5. The electric hoist according to claim 5, wherein the electric hoist is provided within a range until a braking force equal to or less than a predetermined braking force is applied to the parking brake by the electric hoist when the parking brake is not operated. 5. The electric parking brake device according to claim 1, wherein the abnormality is detected by controlling the driving of the unit. 6. The electric hoisting means as long as the parking brake is operating, the hoisting or rewinding by the electric hoisting means so that the braking force of the parking brake does not change by a predetermined braking force or more. 2. A means for controlling the driving of the motor to detect the abnormality.
5. The electric parking brake device according to any one of claims 4 to 4. 7. The electric motor according to claim 5, wherein the abnormality detecting means detects the abnormality by driving the electric hoisting means at a speed lower than a driving speed at the time of operating or releasing the parking brake. Parking brake device. 8. An electric parking brake device having electric hoisting means capable of operating a parking brake by winding up a cable of a parking brake, wherein the electric hoisting means detects a tension of the cable of the parking brake; Abnormality detecting means for detecting abnormality of the parking brake based on a change in the tension of the cable detected by the tension detecting means when the cable is wound or unwound by means. 9. The electric parking brake device according to claim 8, wherein said tension detecting means is means for detecting said tension based on electric power supplied to said electric hoisting means. 10. The electric parking brake device according to claim 1, further comprising: a brake pedal depression detection unit that detects that a brake pedal is depressed, wherein the abnormality detection unit includes the brake pedal. An electric parking brake device which is means for detecting the abnormality while detecting that the brake pedal is being depressed by depressing detection means. 11. The electric parking brake device according to claim 1, wherein the abnormality detecting means detects an abnormality in elongation of the cable. 12. The electric parking brake device according to claim 1, further comprising an output unit that outputs the abnormality when the abnormality is detected by the abnormality detection unit.