JP7238696B2 - Wear detector and brake system - Google Patents

Description

The present invention relates to wear detectors and brake systems.

Patent Literature 1 listed below proposes a brake control device that automatically controls the distribution of regenerative braking and mechanical braking based on the temperature of brake pads in order to stabilize braking performance.

JP 2005-014692 A

The invention described in Patent Document 1 aims to minimize wear, and as long as the vehicle continues to be used, wear of the brake pads will inevitably cause a situation in which desired braking force cannot be produced. Therefore, if there is a possibility that the desired braking force cannot be produced, it is necessary to inspect or replace the brake pads. However, at present, the user (for example, the driver) cannot easily grasp the degree of wear of the brake pads, and it is difficult to determine the appropriate time to inspect or replace the brake pads.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wear detection device and a brake system that allow a user to grasp the appropriate timing for inspection or replacement of brake pads. .

(1) One aspect of the present invention is a wear detection device that detects wear of a friction material used in a mechanical brake of a vehicle, comprising: a first detection unit that detects a braking amount of the mechanical brake; determining the deceleration of the vehicle decelerated by the braking amount detected by the first detection unit, and comparing the determined deceleration with the lower limit value of the allowable range of the deceleration due to the braking amount; A wear detection device comprising: a processing section that executes a first comparison process; and an output section that outputs a comparison result of the first comparison process.

(2) In the wear detection device according to (1) above, the output unit outputs the The comparison result may be output.

(3) The wear detection device according to (1) or (2) above, further comprising a second detection unit that detects a rotational speed of a wheel of the vehicle, wherein the processing unit detects the second detection unit. You may obtain|require the said deceleration from the rotational speed detected by.

(4) In the wear detection device according to any one of (1) to (3) above, the braking amount of the mechanical brake may be an operation amount of a brake pedal of the vehicle or an oil pressure of a master cylinder.

(5) In the wear detection device according to any one of (1) to (4) above, the processing unit is decelerated by the first braking amount detected by the first detection unit during the first period. a reference value setting unit that sets a value smaller than the deceleration by a predetermined value as the lower limit; and a second braking amount detected by the first detection unit during a second period after the first period. is equal to or can be equated with the first braking amount, a comparison unit that executes the first comparison process for comparing the deceleration decelerated by the second braking amount and the lower limit value wherein, in the first comparison processing, if the deceleration decelerated by the second braking amount is equal to or less than the lower limit value, the output unit outputs the result of the first comparison processing as an alarm. The information may be output by at least one method of sound, lighting display of an indicator lamp, and screen display of a display device.

(6) A braking system comprising the wear detection device of (5) above and a mechanical braking device that applies a braking force to the vehicle using the friction material, wherein the comparison unit, in the second period, When the second braking amount detected by the first detection unit is the same as or can be regarded as the same as the first braking amount, the deceleration reduced by the second braking amount and the lower limit value and the output unit performs a second comparison process for comparing the second comparison process with a threshold that is a lower value, and the output unit determines that the deceleration decelerated by the second braking amount is equal to or less than the threshold as a result of the second comparison process. In the braking system, the mechanical braking device is notified to the mechanical braking device, and the mechanical braking device stops the vehicle upon receiving the notification from the output section.

As described above, according to the present invention, the driver can know when to inspect or replace the brake pads.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of schematic structure of the brake system 1 provided with the wear detection apparatus which concerns on this embodiment. It is a figure which shows an example of schematic structure of the wear detection apparatus 3 which concerns on this embodiment. 4 is a flow chart of the operation of the wear detection device 3 according to this embodiment; FIG.

A wear detection device and a brake system according to the present embodiment will be described below with reference to the drawings.

FIG. 1 is a diagram showing an example of a schematic configuration of a brake system 1 equipped with a wear detection device according to this embodiment. A brake system 1 is mounted on a vehicle A. Vehicle A may be manned or unmanned. Vehicle A may be a self-driving car. Further, the vehicle A may be manned and operated by a driver, or may be unmanned and remotely operated by an operator. In this embodiment, a case where the vehicle A is steered by the driver will be described.

As shown in FIG. 1 , a braking system 1 according to this embodiment includes a mechanical braking device 2 and a wear detection device 3 .

The mechanical braking device 2 generates braking force on the wheels W of the vehicle A by mechanical braking. The wheels W may be front wheels, rear wheels, or both front and rear wheels.

The wear detection device 3 detects the degree of wear of the friction material used in the mechanical brake of the vehicle A. As shown in FIG. Then, the wear detector 3 notifies the user when the degree of wear of the friction material is higher than the specified value. Here, for example, the user may be a passenger on board the vehicle A, a driver, a remote operator or a remote monitor of the vehicle A, or both. good too.

An example of a schematic configuration of the mechanical brake device 2 according to this embodiment will be described below.
The mechanical brake device 2 includes a brake pedal 4 , a brake pedal stroke sensor 5 , a master cylinder 6 , a hydraulic sensor 7 , a brake actuator 8 , a brake mechanism 9 , a motor 10 , a drive device 11 , a rotation sensor 12 and a vehicle speed sensor 13 .

The brake pedal 4 receives an operation (brake operation) from the driver or an actuator (not shown). For example, the brake operation is an operation of stepping on the brake pedal 4 by the driver. Also, the brake operation may be an operation in which the actuator pushes the brake pedal 4 .

A brake pedal stroke sensor 5 is provided on the brake pedal 4 and measures an operation amount S of the brake pedal 4 due to brake operation at regular intervals. The brake pedal stroke sensor 5 then outputs the measured operation amount S to the wear detection device 3 . Note that when the driver depresses the brake pedal 4 , the operation amount S is the depressing amount of the brake pedal 4 .

The master cylinder 6 is connected to the brake pedal 4 and generates hydraulic pressure according to braking operation on the brake pedal 4 .
The hydraulic sensor 7 measures the hydraulic pressure P (hereinafter referred to as “brake hydraulic pressure”) generated by the master cylinder 6 at regular intervals and outputs the measured brake hydraulic pressure P to the wear detection device 3 . However, the oil pressure sensor 7 may measure the brake oil pressure P at regular intervals only when the brake pedal 4 is being operated.

The brake actuator 8 supplies hydraulic pressure generated by the master cylinder 6 to the brake mechanism 9 .

The brake mechanism 9 may be a disc brake or a drum brake. Therefore, the "friction material" of the present invention may be a brake pad or a brake shoe. In the following description, it is assumed that the brake mechanism 9 is a disc brake.

The brake mechanism 9 includes a brake disc rotor 91 , a brake caliper 92 and brake pads 93 .
The brake disc rotor 91 rotates together with the wheel W.
The brake caliper 92 presses the brake pad 93 against the brake disc rotor 91 by hydraulic pressure supplied from the brake actuator 8 . As a result, a braking force corresponding to the operation amount S or the hydraulic pressure P is generated in the vehicle W.

The brake pad 93 generates frictional force (braking force) by coming into contact with the brake disc rotor 91 . The brake pad 93 is an example of the "friction material" of the present invention. The frictional force of the brake pad 93 decreases as it wears. Therefore, the brake pad 93 is a consumable item and needs to be replaced.

The motor 10 is a driving source for the wheels W and causes the vehicle W to generate driving force. This driving force rotates the wheels W and the vehicle A runs.

The driving device 11 controls rotation of the motor 10 .
The rotation sensor 12 detects rotation of the motor 10 and outputs a detection signal (for example, a pulse signal) corresponding to the rotation of the motor 10 . The rotation sensor 12 is, for example, a resolver.

The vehicle speed sensor 13 measures the speed of the vehicle A (hereinafter referred to as "vehicle speed") Vc at regular intervals. Then, the vehicle speed sensor 13 outputs the speed of the vehicle A (hereinafter referred to as “vehicle speed”) Vc to the wear detection device 3 .

Next, an example of a schematic configuration of the wear detection device 3 according to this embodiment will be described. FIG. 2 is a diagram showing an example of a schematic configuration of the wear detection device 3 according to this embodiment.

As shown in FIG. 2 , the wear detection device 3 includes a first detection section 20 , a second detection section 21 , a processing section 22 and an output section 23 .

The first detection unit 20 detects the amount of braking br that the mechanical brake device 2 generates on the wheels W. As shown in FIG. The braking amount br indicates the degree of braking force that the mechanical braking device 2 generates to the wheels W. As shown in FIG. For example, the braking amount br is the operation amount S of the brake pedal or the brake hydraulic pressure P. In this embodiment, the first detection unit 20 detects the braking amount br by acquiring the operation amount S from the brake pedal stroke sensor 5 at regular intervals. However, the first detection unit 20 may detect the braking amount br by acquiring the brake hydraulic pressure P from the hydraulic pressure sensor 7 at regular intervals. The first detection unit 20 outputs the detected braking amount br to the processing unit 22 .
Further, the first detection unit 20 detects the operation amount S as the braking amount br, and when there is a failure in the brake pedal stroke sensor 5 (for example, when it is determined that the operation amount S is an abnormal value) may detect the brake hydraulic pressure P as the braking amount br.

The second detection unit 21 detects the rotation speed Vr by calculating the rotation speed Vr of the wheel A at regular intervals based on the detection signal from the rotation sensor 12 . The second detector 21 then outputs the detected rotation speed Vr to the processor 22 .

The processing unit 22 obtains the deceleration a of the vehicle A decelerated by the braking amount br detected by the first detection unit 20 from the rotation speed Vr. Then, the processing unit 22 compares the obtained deceleration a with the lower limit value of the allowable range of the deceleration a due to the braking amount br (hereinafter referred to as "first reference value ath1"). comparison processing. When the deceleration a is less than or equal to the first reference value ath1, it means that the effectiveness of the mechanical brake is poor.

The output unit 23 outputs the comparison result of the first comparison process. For example, in the first comparison process, if the deceleration a is equal to or less than the first reference value ath1, the output unit 23 outputs the result of the first comparison process as an alarm sound and an indicator light including a warning light. output by at least one method of lighting display and screen display of the display device. Thereby, the output unit 23 can notify the user that the effectiveness of the mechanical brake is deteriorating. The output unit 23 may have at least one of a sound output unit that outputs the alarm sound, the indicator lamp, and the display device. Further, in the first comparison process, if the deceleration a is equal to or less than the first reference value ath1, the output unit 23 outputs the result of the first comparison process to the user's communication device by wire or wirelessly. You may The communication device may be a mobile information terminal such as a smart phone or a tablet terminal.

Note that the output unit 23 may output the result of the first comparison process when the deceleration a is equal to or greater than the first reference value ath1 in the first comparison process. For example, the output unit 23 displays the indicator lamp in the first mode when the deceleration a is equal to or less than the first reference value ath1, and displays the indicator lamp in the first mode when the deceleration a is equal to or greater than the first reference value ath1. The indicator lamp is displayed in a second manner different from the first manner.

Next, an example of a schematic configuration of the processing unit 22 according to this embodiment will be described. The processing unit 22 may be configured by a microprocessor such as a CPU or MPU, a microcontroller such as an MCU, or the like.

The processing unit 22 includes a deceleration calculation unit 30 , a reference value setting unit 31 , a storage unit 32 and a comparison unit 33 .

The deceleration calculator 30 obtains the deceleration a based on the rotational speed Vr output from the second detector 21 . However, in the present embodiment, the deceleration calculator 30 is not particularly limited to the calculation method as long as it can calculate the deceleration a. For example, the deceleration calculator 30 may calculate the deceleration a based on the vehicle speed V from the vehicle speed sensor 13 .
For example, the deceleration calculator 30 may obtain the deceleration a based on the rotational speed Vr, and may obtain the deceleration a based on the vehicle speed V when it is determined that the rotational speed Vr is an abnormal value.

The reference value setting unit 31 sets the deceleration a (hereinafter, “ (referred to as a first deceleration a1”) is acquired from the deceleration calculation unit 30. Then, the reference value setting unit 31 sets a value smaller than the first deceleration a1 by a predetermined value as the first reference value ath1. The predetermined value is set in advance, and may be determined by experiments or the specifications of the brake pad 93, for example. The reference value setting unit 31 stores the first braking amount br1 and the first reference value ath1 in the storage unit 32 in association with each other. The first braking amount br1 and the first reference value ath1 may be one data set or a plurality of data sets.

Here, the first period H1 is a period in which the degree of wear of the brake pad 93 is low. For example, the first period H1 is a period from when the brake pad 93 first contacts the brake disc rotor 91 until a predetermined time (for example, several minutes or several hours) elapses. For example, when the brake pad 93 first contacts the brake disc rotor 91 is when braking force is applied to the wheel W for the first time. Also, the first period H1 may be the period when the brake system 1 is installed in the vehicle A at the beginning.

Note that the reference value setting unit 31 may reset the first reference value ath1 stored in the storage unit 32 when the brake pad 93 is replaced. Then, the reference value setting unit 31 may set a new first braking amount br1 each time the brake pad 93 is replaced. Here, the wear detection device 3 is provided with an operation unit (not shown), and when the reference value setting unit 31 receives a signal from the operation unit indicating that the operation unit has been operated, the brake pad 93 is replaced. It may be determined that

The storage unit 32 stores a first braking amount br1 and a first reference value ath1 that are associated with each other.

The comparison unit 33 determines that the braking amount br detected by the first detection unit 20 (hereinafter referred to as “second braking amount br2”) during the second period H2 after the first period H1 is stored in the storage unit It is determined at regular intervals whether the value is the same as or can be regarded as the same as the first braking amount br1 stored in 32 . For example, when the second braking amount br2 is within a predetermined range centered on the first braking amount br1, the comparison unit 33 determines that the second braking amount br2 and the first braking amount br1 are equal to each other. It is determined that they can be equated with the same.

When the comparison unit 33 determines that the second braking amount br2 is the same as or can be regarded as the same as the first braking amount br1, the deceleration a( hereinafter referred to as “second deceleration a2”) is acquired from the deceleration calculation unit 30, and the first reference value ath1 associated with the first braking amount br1 is read from the storage unit 32. Then, the comparison unit 33 performs a first comparison process of comparing the second deceleration a2 and the first reference value ath1. The timing at which the comparison unit 33 acquires the second deceleration a2 from the deceleration calculation unit 30 determines that the second braking amount br2 is the same as or can be regarded as the same as the first braking amount br1. may be before

If the second deceleration a2 is less than or equal to the first reference value ath1 as a result of the first comparison processing in the second period H1, the comparison unit 33 compares the second deceleration a2 with the second deceleration a2. A second comparison process may be performed to compare with the reference value ath2 (threshold). Here, the second reference value ath2 is a value lower than the first reference value ath1.
The output unit 23 may notify the driving device 11 when the second deceleration a2 is equal to or less than the second reference value ath2 as a result of the second comparison processing. Upon receiving the notification, the driving device 11 controls the rotation of the motor 10 to generate a braking force on the motor 10 to stop the vehicle A. A case where the second deceleration a2 is less than or equal to the second reference value ath2 indicates a state in which the deceleration a is extremely low and the degree of wear of the brake pad 93 is high. In such a state, the braking system 1 may determine that traveling of the vehicle A is dangerous and may stop the vehicle A by the automatic braking function.

Next, the flow of operation of the wear detection device 3 according to this embodiment will be described with reference to FIG. FIG. 3 is a flow chart of the operation of the wear detector 3 according to this embodiment. In the following description, the first braking amount br1 and the first reference value ath1 are already stored in the storage unit 32 in association with each other.

The processing unit 22 acquires the second braking amount br2 that the mechanical brake device 2 is causing to the wheels W from the first detection unit 20 . Also, the processing unit 22 obtains a second deceleration a2 that is decelerated by the second braking amount br2 based on the rotation speed Vr from the second detection unit 21 (step S101). For example, the second deceleration a2 decelerated by the second braking amount br2 is the deceleration a calculated from the rotation speed V when the first detection unit 20 acquires the second braking amount br2. be.

The comparison unit 33 determines whether the second braking amount br2 is the same as or can be regarded as the same as the first braking amount br1 stored in the storage unit 32 (step S102). When the comparison unit 33 determines that the second braking amount br2 is equal to or equated with the first braking amount br1, the comparison unit 33 determines that the first braking amount br2 associated with the first braking amount br1 A reference value ath1 of is read from the storage unit 32 . Then, the comparison unit 33 executes a first comparison process to determine whether or not the second deceleration a2 is equal to or less than the read first reference value ath1 (step S103). On the other hand, when the comparison unit 33 determines that the second braking amount br2 is not the same as the first braking amount br1 or is not a value that can be equated with the first braking amount br1, the process returns to step S101.

When the comparison unit 33 determines in the process of step S103 that the second deceleration a2 is equal to or less than the first reference value ath1, the second deceleration a2 is equal to or less than the second reference value ath. A second comparison process for determining whether or not there is is executed (step S104). On the other hand, when the comparison unit 33 determines in the process of step S103 that the second deceleration a2 is not equal to or less than the first reference value ath1, the process returns to step S101.

When it is determined in the process of step S104 that the second deceleration a2 is equal to or less than the second reference value ath2, the output unit 23 executes a notification process of outputting the result of the second comparison process. At the same time, it is notified by outputting a stop signal for stopping the vehicle A to the driving device 11 (step S105). For example, as notification processing, the output unit 23 outputs the result of the second comparison processing by at least one of an alarm sound, lighting display of indicator lamps including warning lamps, and screen display of a display device. In addition, the output unit 23 may output the result of the second comparison process to the user's communication device by wire or wirelessly as the notification process.
Upon receiving the stop signal, the driving device 11 causes the motor 10 to generate a braking force, thereby stopping the vehicle A.

On the other hand, when it is determined in the process of step S104 that the second deceleration a2 is not equal to or less than the second reference value ath2, the output unit 23 outputs the result of the first comparison process (the second deceleration a2 is less than or equal to the first reference value ath1) is executed (step S106). The notification processing method is the same as the notification processing described in step S105.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design and the like are included within the scope of the gist of the present invention.

(Modification 1) Although the processing unit 22 according to the above embodiment sets the first reference value ath1 from the deceleration a in the first period H1, the present invention is not limited to this. For example, the processing unit 22 may acquire the first reference value ath1 and the first braking amount br1 from an external device and store them in the storage unit 32 .

(Modification 2) The processing unit 22 according to the above embodiment may obtain the ratio R (a1/br1) of the deceleration a to the braking amount br from the first braking amount br1 and the first deceleration a1. . Then, the processing unit 22 may use the second braking amount br2 and the ratio R to calculate the first reference value ath1 (for example, br2×R). As a result, the first reference value ath1 fluctuates according to the second braking amount br2. Therefore, the processing unit 22 does not need to perform the processing of step S102 in FIG. 3, and can reduce the processing load.

(Modification 3) The processing unit 22 according to the above embodiment may perform the first comparison processing and the second comparison processing at the sampling period of the braking amount br or the calculation period of the deceleration a. You can also do it only on certain days (for example, every Sunday). That is, the timing of the first comparison process and the second comparison process can be set arbitrarily.

(Modification 4) Although the comparison unit 33 of the above embodiment executes the first comparison process for determining whether or not the second deceleration a2 is equal to or less than the first reference value ath1, the present invention is limited to this. not. That is, the comparison unit 33 may obtain the ratio R2 of the second deceleration a2 to the second braking amount br2. As a first comparison process, the comparison unit 33 obtains Rth that is lower than the ratio R1 of the first deceleration a1 to the first braking amount br1 by a predetermined value, and compares the ratio R2 with the ratio Rth. good too. Then, the output unit 23 may execute the process of step S106 when the ratio R2 becomes equal to or less than the ratio Rth.

As described above, the wear detection device 3 according to the present embodiment obtains the deceleration a of the vehicle decelerated by the braking amount br detected by the first detection unit 20, and the obtained deceleration a, A processing unit 22 is provided for executing a first comparison process for comparing the allowable lower limit value (first reference value ath1) of the deceleration a by the braking amount br. The wear detection device 3 also includes an output unit 23 that outputs the comparison result of the first comparison process.

According to such a configuration, the user can grasp the appropriate timing for inspection or replacement of the brake pads.

In the conventional brake system, the user is not notified when it is time to replace the brake pads 93 used in the mechanical brake. Therefore, the actual situation is that the user of the vehicle A replaces the brake pad 93 at an appropriate time, or replaces the brake pad 93 at the request of a maintenance company during a periodic inspection. As a result, if the brake pads 93 are replaced early, the brake pads 93 that can still be used will be wasted. On the other hand, if the replacement timing of the brake pads 93 is delayed, the probability of accidents caused by wear of the brake pads 93 may increase.

In this embodiment, the wear detection device 3 notifies the user when the deceleration a becomes equal to or less than the first reference value ath1 (when the braking effectiveness becomes poor). Accordingly, the driver can grasp the appropriate timing for inspection or replacement of the brake pads from the notification.

All or part of the wear detection device 3 described above may be realized by a computer. In this case, the computer may include a processor such as a CPU or GPU and a computer-readable recording medium. Then, a program for realizing all or part of the functions of the wear detection device 3 by a computer is recorded on the computer-readable recording medium, and the program recorded on the recording medium is read by the processor, It may be realized by executing The term "computer-readable recording medium" as used herein refers to portable media such as flexible disks, magneto-optical disks, ROMs, and CD-ROMs, and storage devices such as hard disks incorporated in computer systems. Furthermore, "computer-readable recording medium" means a medium that dynamically retains a program for a short period of time, like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. It may also include something that holds the program for a certain period of time, such as a volatile memory inside a computer system that serves as a server or client in that case. Further, the program may be for realizing a part of the functions described above, or may be capable of realizing the functions described above in combination with a program already recorded in the computer system. It may be implemented using a programmable logic device such as FPGA.

A vehicle 1 brake system 2 mechanical brake device 3 wear detection device 20 first detection unit 21 second detection unit 22 processing unit 23 output unit 30 deceleration calculation unit 31 reference value setting unit 32 storage unit 33 comparison unit

Claims (6)

A wear detection device for detecting wear of a friction material used in a vehicle mechanical brake,
a first detection unit that detects a braking amount of the mechanical brake;
A deceleration of the vehicle decelerated by the braking amount detected by the first detection unit is obtained, and the obtained deceleration is compared with a lower limit value of an allowable range of the deceleration due to the braking amount. a processing unit that executes a comparison process of 1;
an output unit that outputs a comparison result of the first comparison process;
A wear detection device comprising: 2. The output unit outputs the comparison result only when the deceleration is equal to or less than the lower limit as a result of the comparison between the deceleration and the lower limit by the processing unit. The wear detection device according to . Further comprising a second detection unit that detects the rotational speed of the wheels of the vehicle,
the processing unit obtains the deceleration from the rotation speed detected by the second detection unit;
3. The wear detection device according to claim 1 or 2, characterized in that: The wear detection device according to any one of claims 1 to 3, wherein the braking amount of the mechanical brake is an operation amount of a brake pedal of the vehicle or an oil pressure of a master cylinder. The processing unit is
a reference value setting unit configured to set the lower limit value to a value smaller by a predetermined value than the deceleration decelerated by the first braking amount detected by the first detection unit in the first period;
In a second period after the first period, when the second braking amount detected by the first detection unit is the same as or can be regarded as the same as the first braking amount, the second braking amount is a comparison unit that performs the first comparison process for comparing the deceleration decelerated by the braking amount and the lower limit;
with
In the first comparison process, if the deceleration decelerated by the second braking amount is equal to or less than the lower limit value, the output unit outputs the result of the first comparison process by an alarm sound, an indicator light, or the like. The wear detector according to any one of claims 1 to 4, wherein output is performed by at least one method of lighting display of the display device and screen display of the display device. A wear detection device according to claim 5;
a mechanical braking device that applies a braking force to the vehicle with the friction material;
A braking system comprising
If the second braking amount detected by the first detecting unit is the same as or can be regarded as the same as the first braking amount in the second period, the comparing unit detects the second braking amount. performing a second comparison process that compares the deceleration decelerated by an amount with a threshold that is a value lower than the lower limit;
If the deceleration decelerated by the second braking amount is equal to or less than the threshold value as a result of the second comparison processing, the output unit notifies the mechanical brake device,
The mechanical brake device stops the vehicle upon receiving a notification from the output unit.
A braking system characterized by:

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