JP6597706B2 - Vehicle state estimation device and notification device using the same - Google Patents

Description

  The present invention relates to a vehicle state estimation device that electrically estimates a wear state of a brake pad in a vehicle braking device including a hydraulic brake device and an electric brake device, and a notification device using the vehicle state estimation device.

In general, in order to detect the wear state of a brake pad installed in a brake device of a vehicle, the brake pad is operated by actually operating the brake device and whether or not an abnormal noise is generated when the brake device is operated. There was no choice but to judge whether it was worn or not.
In order to solve such problems, the electric brake device disclosed in Patent Document 1 has already been invented.

  That is, a motor rotation angle detected by the motor rotation angle detection means, comprising motor rotation angle detection means for detecting a motor rotation angle in an electric motor of an EPB apparatus (Electric Parking Break) and brake force estimation means for estimating a brake force. And the brake force required by the brake force estimation means are compared with the predetermined correlation between the motor rotation angle and the brake force when the brake pad is not worn, to estimate the current amount of wear of the brake pad. is there.

  The electric brake device disclosed in Patent Document 1 has an advantage that the wear state of the brake pad can be estimated. On the other hand, the hydraulic brake device (Dynamic Stability Control System, Dynamic Stability Control System, DSC for short). Device) and EPB device (electric brake device) in combination, when estimating the wear state of the brake pad, if the hydraulic brake device is operating, the brake pad is already pressed by the hydraulic pressure. Therefore, there is a problem that it is difficult to accurately estimate the brake pad wear state.

Japanese Patent Laying-Open No. 2015-187483

  Therefore, the present invention electrically estimates the wear state of the brake pad in a vehicle in which the hydraulic brake device (DSC device) and the electric brake device (EPB device) are used in combination, and provides information on the wear of the brake pad. An object of the present invention is to provide a vehicle state estimation device that can notify a passenger of a vehicle and a notification device using the vehicle state estimation device.

According to the vehicle state estimation device of the present invention, in the vehicle braking device including the hydraulic brake device and the electric brake device, the motor that drives the electric brake device and the current output to the motor reach a peak value. Motor current value detecting means for detecting a gradient of the current value of the electric brake device, wherein the current value rises in the initial stage of operation of the electric brake device, and the first gradient portion extends from a peak value to a base value. And a second gradient portion that rises from the constant portion to the next peak value, and the detection range of the current value of the motor current value detecting means includes the constant portion that decreases and thereafter maintains a constant low current value. An operating means for operating the electric brake device when the hydraulic brake device is in an inoperative state, and detecting a current value during operation of the electric brake device, between the base value and the peak value of the second gradient portion The comparison means for comparing whether or not the distribution is larger than the reference gradient of the current value when the brake pad that is not worn is obtained in advance, and the detection gradient of the current value based on the comparison result of the comparison means Determining means for estimating that the brake pad is in a worn state when greater than the gradient; and determining means for determining whether or not the detected gradient in the second gradient portion of the motor current value is close to a reference gradient. And when the determination means determines that the virtual extension line needs to be set, virtual extension lines are set along the reference gradient and the detection gradient, respectively, and the comparison means Is compared with the reference gradient .

According to the above configuration, the motor current value detection means detects the gradient of the current value (the gradient of the second gradient section) until the current output to the motor reaches the peak value.
The operating means described above operates the electric brake device when the hydraulic brake device is not operated.
The comparison means described above compares whether or not the detected gradient of the current value during operation of the electric brake device is greater than the previously determined reference gradient of the current value when the brake pad is not worn.
The estimation means estimates that the brake pad is in a worn state when the current value detection gradient is larger than the reference gradient based on the comparison result of the comparison means.

In this way, the reference gradient of the current value when the brake pad that is not worn is mounted is compared with the detection gradient of the current value in the vehicle on which the detected brake pad to be worn is detected, and the detected gradient When is larger than the reference gradient, it is estimated that the brake pad is in a worn state, so that the wear state of the brake pad can be reliably estimated.
In addition , since the estimation of the wear state described above is executed in a state where the hydraulic brake device is not operating, the brake pad is not applied with hydraulic pressure, and the wear state of the brake pad is accurately estimated. can do.

Further , since the virtual extension lines are set along the reference gradient and the detection gradient , even if the reference gradient and the detection gradient are close to each other, each virtual extension line is set by the setting of the virtual extension line. The gap between the gradients can be enlarged, and the wear state of the brake pad can be estimated by the size of the enlarged gap . For this reason, estimation of a wear state becomes easy.

Furthermore , the comparison means compares the detection gradient including the virtual extension line with a reference gradient.

Thereby , the wear state of the brake pad can be easily estimated by comparing the gradients of the current values including the virtual extension line without requiring high resolution.

  The alarm device using the vehicle state estimation device according to the present invention is the vehicle state estimation device according to claim 1, wherein when the brake pad is estimated to be in a worn state by the estimation means, the brake pad wear information is provided. Is provided with an informing means for informing the passenger.

According to the said structure, the wear information of a brake pad can be alert | reported to a passenger | crew (driver) by the above-mentioned alerting | reporting means.
In addition, the above-mentioned alerting | reporting means may be set to the alerting | reporting lamp provided in an instrument panel, a multi-information display, and may be set to a vehicle-mounted speaker.

  According to the present invention, in a vehicle in which a hydraulic brake device (DSC device) and an electric brake device (EPB device) are used in combination, the wear state of the brake pad is electrically accurately estimated, and the brake pad wear information is provided. Can be notified to the occupant.

Schematic diagram of a vehicle equipped with a vehicle state estimation device of the present invention and a notification device using the same Sectional view showing the electric brake device Control circuit block diagram showing a vehicle state estimation device and a notification device using the same Flow chart showing wear state estimation of brake pads Explanatory drawing which shows the electric current value change of the electric motor with respect to time Explanatory diagram showing changes in motor speed with respect to torque

In a vehicle in which a hydraulic brake device (DSC device) and an electric brake device (EPB device) are used in combination, the brake pad wear state is electrically accurately estimated and the brake pad wear information is reported to the occupant. The purpose is to detect a gradient of a current value until a motor driving the electric brake device and a current output to the motor reach a peak value in a vehicle braking device including a hydraulic brake device and an electric brake device. Motor current value detecting means, and the current value rises at the initial stage of operation of the electric brake device, and the first gradient part decreases from a peak value to a base value, and then reaches a constant low value. A constant portion that maintains the current value and a second gradient portion that rises from the constant portion to the next peak value, and the current value detection range of the motor current value detection means is the second value Between the base value and the peak value of the distribution section, an operating means for operating the electric brake device in a non-operating state of the hydraulic brake device, and a current value detection gradient during operation of the electric brake device, The comparison means for comparing whether or not the current value when the brake pad is not worn is larger than the reference slope, and the current value detection slope is larger than the reference slope based on the comparison result of the comparison means. An estimation means for estimating that the brake pad is in a worn state, and provided with a determination means for determining whether or not a detected gradient in the second gradient portion of the motor current value is close to a reference gradient, When the determination means determines that the virtual extension line needs to be set, virtual extension lines are set along the reference gradient and the detection gradient, respectively, and the comparison means It was realized by configuration that compares the detected slope and reference slope including in.

An embodiment of the present invention will be described below in detail with reference to the drawings.
The drawings show a vehicle state estimation device and a notification device using the vehicle state estimation device, and FIG. 1 is a schematic diagram of the vehicle equipped with the vehicle state estimation device and the notification device.

  As shown in FIG. 1, a vehicle according to this embodiment includes a foot brake device 1 (foot brake mechanism), a DSC (Dynamic Stability Control System) device 2 (hydraulic brake device), and an EPB (Electric Parking Break) device 3. (Electric parking brake device), ECU (Electronic Control Unit) 4 (control means), and the like.

On the other hand, the engine 5 transmits driving force (driving torque) to the automatic transmission 6 (so-called AT) by fastening a clutch via a torque converter.
The engine 5 stops fuel injection when receiving an engine stop execution command from the engine control unit, and executes a restart operation when receiving an engine restart execution command.

  The automatic transmission 6 receives an input signal from each sensor, converts the driving force input from the engine 5 into a predetermined torque and rotation speed according to the running state and the shift range selected by the occupant, It is transmitted to the drive wheel via a differential device.

  As shown in FIG. 1, the shift device 7 is installed inside the device, a shift lever 8 that can be operated by a passenger, a shift indicator corresponding to each of the D, N, R, and P ranges set in order from the bottom. A shift position sensor (not shown) is provided.

  The shift position sensor is an occupant based on a relative position between a movable sensor provided on a slider that slides in response to movement of the shift lever 8 and a fixed sensor provided on a support portion (not shown) that supports the slider. Detects a shift position corresponding to the selected shift range.

Next, the foot brake device 1 will be described.
The foot brake device 1 supplies brake fluid (hereinafter simply referred to as brake fluid pressure) pressurized according to the depression operation of the brake pedal 11 to the two pairs of front and rear hydraulic brake mechanisms 12 to provide two pairs of front and rear wheels. 10 is configured to be brakeable.

As shown in FIG. 1, the foot brake device 1 includes a brake pedal 11, a master cylinder 13, a booster 14, a hydraulic brake mechanism 12, and the like.
The booster 14 has a movable wall (not shown) that is movable in the axial direction in conjunction with the brake pedal 11, and brakes using the differential pressure between the negative pressure chamber and the atmospheric chamber partitioned by the movable wall. The pedal 11 is stepped up. The hydraulic brake mechanism 12 provided on each wheel 10 is connected to the master cylinder 13 by an oil passage, and applies a braking force to each wheel 10 in accordance with the depression operation of the brake pedal 11 by an occupant. In FIG. 1, reference numeral 23 denotes an accelerator pedal.

FIG. 2 is a sectional view showing an electric parking brake device (EPB device).
As shown in FIG. 2, each hydraulic brake mechanism 12 includes a disk rotor 15 provided so as to be integrally rotatable with the wheel 10, a caliper 16 that can apply a braking force to the disk rotor 15, and the like. The caliper 16 includes a caliper body 17 that is disposed across the disk rotor 15 in a bowl shape, and outer brake pads 18 that are disposed on both sides of the disk rotor 15 inside the caliper body 17 and an inner side. And a side brake pad 19.

  Inside the inner brake pad 19 is disposed a piston portion 21 that can move in the axial direction of the disc rotor 15, and this piston portion 21 slides on the inner periphery of the wheel cylinder 22 supported by the caliper body 17. It is movably inserted. An oil passage is connected to the inside of the wheel cylinder 22.

When the occupant depresses the brake pedal 11, the brake fluid pressure flows through the oil passage and is supplied into the wheel cylinder 22 to advance the piston portion 21 outward in the axial direction.
Accordingly, the outer brake pad 18 is pressed inside the disk rotor 15, and the caliper body 17 is moved inward by this reaction force, and the outer brake pad 18 is pressed outside the disk rotor 15. Thereby, the braking force of the foot brake device 1 is generated.

Next, the DSC apparatus 2 will be described.
The DSC device 2 (hydraulic brake device) is configured to be able to brake the front two wheels 10 and the rear two wheels 10 independently of the depression operation of the brake pedal 11.

Next, the EPB apparatus 3 will be described.
The EPB device 3 is driven independently of the depression operation of the brake pedal 11, and when a predetermined condition is satisfied, the piston portion 21 in the wheel cylinder 22 shown in FIG. 2 is driven to brake the rear two wheels 10. Thus, it is formed so as to maintain the stop state of the vehicle.

The EPB device 3 includes an EPB control unit provided in the ECU 4, an electric brake mechanism 31 (see FIGS. 1 and 2), and the like.
The EPB control unit receives an input signal from each sensor and controls the wheel braking force of the electric brake mechanism 31. Specifically, the EPB control unit controls the wheel braking force of the electric brake mechanism 31 to be a predetermined load based on the ON signal of the EPB switch 32 (see FIGS. 1 and 3).
The above-mentioned EPB switch 32 is provided in the upper part of the center console in the vehicle interior.

  As shown in FIG. 2, the electric brake mechanism 31 includes an electric motor M. A pinion 33 is fitted to the output shaft of the electric motor M, and is provided outside the wheel cylinder 22 on one end side of the screw 34. The reduction gear 35 and the above-described pinion 33 are engaged with each other.

  Further, the above-described screw 34 is located in the wheel cylinder 22, and a spindle nut 36 is screwed to the other end portion of the screw 34. The spindle nut 36 is disposed on the inner peripheral portion of the piston portion 21. When the electric motor M rotates forward, the piston portion 21 is advanced in the braking direction via the elements 33, 35, 34, and 36, and the electric motor is driven. At the time of reverse rotation of M, the piston portion 21 is configured to be retracted in the braking release direction, that is, the release direction via the elements 33, 35, 34, and 36.

FIG. 5 is an explanatory diagram showing changes in the current value of the electric motor M in the EPB device 3, and FIG. 6 is an explanatory diagram showing changes in the motor rotation speed of the electric motor M with respect to torque.
As shown in FIG. 5, the value of the current flowing through the electric motor M of the EPB device 3 rises steeply due to the starting torque at the start of the motor, and then decreases from the peak value “a” to the base value “b”. It goes through a constant part c that maintains a constant low current value that moves forward.

Next, since the brake pads 19 and 18 are pressed against the disc rotor 15 from the touch disc portion d where the brake pad 19 contacts the disc rotor 15, the current value rises to the next peak value e with a predetermined gradient as the torque increases. Go up.
The gradient rising at the initial stage of the operation of the electric motor M is defined as a first gradient portion A, and the gradient from the touch disk portion d to the next peak value e after the constant portion c has elapsed is defined as a second gradient portion B. And

In short, the current value of the electric motor M is such that the first gradient part A that rises in the initial stage of operation of the EPB device 3, the first gradient part A decreases from the peak value a to the base value b, and then a constant low current value. And a second gradient part B rising from the constant part c to the next peak value e.
Here, the second gradient (specifically, the gradient of the second gradient portion B) of the current value when the brake pads that are not worn are mounted is defined as the reference gradient B0, and the detected brake pads 18 and 19 whose wear state should be detected are The second gradient (specifically, the gradient of the second gradient portion B) of the current value of the electric motor M in the mounted vehicle is set as the detection gradient B1.

  As shown in FIG. 5, the detected gradient B1 increases as the wear of the brake pads 18 and 19 progresses with respect to the reference gradient B0 at the current value when the brake pads are not worn.

  FIG. 6 shows the reason why the motor current value changes due to wear of the brake pads 18 and 19 by taking the torque on the horizontal axis and the motor rotation speed of the electric motor M of the EPB device 3 on the vertical axis. FIG.

  In the case of a brake pad that is not worn as shown by the characteristic f in FIG. 6, the brake pad is in a non-wearing and soft state. Therefore, even if it is pressed against the disk rotor 15, the brake pad bends and the motor rotation speed decreases. Difficult (see between the touch disk and full clamp in the figure).

  On the other hand, in the case of the worn brake pad indicated by the characteristic g in FIG. 6, the brake pad is thin and hard due to wear, and therefore the brake pad is not easily bent even when pressed against the disc rotor 15. The degree of decrease in the motor rotation speed becomes large. The difference in the degree of decrease in the motor speed of the characteristics f and g in FIG. 6 appears in the difference in the current value shown in FIG. 5, and in particular, the difference between the reference gradient B0 and the detection gradient B1 in FIG.

FIG. 3 is a control circuit block diagram showing a vehicle state estimation device and a notification device using the same.
Next, the ECU 4 will be described with reference to FIG.
The ECU 4 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input side interface, an output side interface, and the like.

  The ROM stores a program (see FIG. 4) for executing brake pad wear state estimation processing, and the RAM is storage means for storing data, maps, and the like used when the CPU performs a series of processing.

  The ECU 4 controls the driving of the DSC device 2, the EPB device 3, and the notification device 39 according to the program stored in the ROM based on the inputs from the EPB switch 32, each wheel speed sensor 37, and the master pressure sensor 38. When the device 3 is in operation, the motor current and motor voltage of the electric motor M are input to the ECU 4.

The EPB switch 32 is provided on the center console, and issues a command to drive the EPB device 3 when the occupant turns on the EPB switch 32.
The wheel speed sensor 37 outputs a signal corresponding to the rotational speed of each wheel 10, and the ECU 4 also has a function of calculating the vehicle speed based on the signal from each wheel speed sensor 37.

  The master pressure sensor 38 is an existing part for detecting the master pressure in the master cylinder 13 in the foot brake device 1, and the master pressure becomes zero when the brake pedal 11 is not depressed. Whether or not the brake pedal 11 is depressed can be detected.

The DSC device 2 (hydraulic brake device) controls braking of the front two wheels 10 and the rear two wheels 10 by hydraulic pressure.
The EPB device 3 (electric brake device) controls the braking of the rear two wheels 10 when the electric motor M is operated.

  The notification device 39 notifies the occupant of wear information of the brake pads 18 and 19 when the brake pads 18 and 19 are estimated to be in a worn state by estimation means (see steps S8 and S12) described later. Thus, the notification device 39 can be configured by a notification lamp, a multi-information display, or a vehicle-mounted speaker provided on the instrument panel.

Further, in the ECU 4 described above, a motor current value detection unit 40 that detects the motor current value when the electric motor M is operated, and a calculation unit 41 that calculates the detection gradient B1 of the second gradient unit B are provided. ing.
The motor current value detection unit 40 described above is based on the calculation result of the calculation unit 41, and the current value between the base value of the second gradient unit B (see the base value b after elapse of the fixed unit c) and the peak value e. This is a motor current value detecting means for detecting the detection gradient B1.

The above-mentioned ECU 4 is an operating means for operating the EPB device 3 (electric brake device) when the DSC device 2 (hydraulic brake device) is not operated (see the routine R1 including steps S2 to S4 in the flowchart shown in FIG. 4). When,
Comparing means for comparing whether or not the current value detection gradient B1 during the operation of the EPB device 3 is larger than the reference gradient B0 of the current value when the brake pads are worn without being determined in advance (see FIG. 4). Steps S7 and S11 in the flowchart)
When the current value detection gradient B1 is larger than the reference gradient B0 based on the comparison result of the comparison means (steps S7 and S11) (see YES determination in steps S7 and S11), the brake pads 18 and 19 are in a worn state. And estimation means (see steps S8 and S12 in the flowchart shown in FIG. 4).

The operation of the vehicle state estimation apparatus configured as described above and the notification apparatus using the same will be described below with reference to the flowchart shown in FIG.
Note that each step of the flowchart shown in FIG. 4 constitutes means corresponding to the processing content. In this embodiment, the current value waveform shown in FIG. 5 is stored in a readable manner as a map in the RAM. Further, a flag (F = 1) is set in a predetermined area of the RAM when the DSC device 2 is operated, and a flag (F = 0) is set when the operation of the DSC device 2 is released.

  In step S1, the ECU 4 executes reading of various necessary signals including a signal from the EPB switch 32 and a flag F in a predetermined area of the RAM.

  Next, in step S2, the ECU 4 determines whether or not the DSC device 2 (hydraulic brake device) is inoperative based on the read flag F content, and when NO is determined (when F = 1), the step S1 is performed. On the other hand, when YES is determined (when F = 0), the process proceeds to the next step S3.

  In this step S3, the ECU 4 determines whether or not the EPB switch 32 has been operated. When NO is determined, the process returns to step S1, while when YES is determined, the process proceeds to the next step S4.

  In step S4, the ECU 4 operates the EPB device 3 (electric brake device) in response to the establishment of two conditions that the DSC device 2 is inactive and the EPB switch 32 is operated. That is, energization to the electric motor M is executed.

  When the electric motor M is driven, the piston portion 21 moves forward in the braking direction via the elements 33, 35, 34, and 36 shown in FIG. 2, and the brake pads 18 and 19 come into contact with the disc rotor 15, and then The brake pads 18 and 19 are pressed against the disc rotor 15. The detection gradient B1 (see FIG. 5) in the second gradient portion B of the motor current value in this case is detected by the motor current value detection portion 40.

Next, in step S5, the ECU 4 determines whether or not the detection gradient B1 of the motor current value is close to the reference gradient B0. That is, in this step S5, it is determined whether or not a virtual extension line needs to be set.
If NO is determined in step S5, the process proceeds to step S11. If YES is determined, the process proceeds to the next step S6.
In step S6, the ECU 4 sets virtual extension lines L0 and L1 along the reference gradient B0 and the detection gradient B1 shown in FIG.

  Next, in step S7, the ECU 4 compares the detection gradient B1 including the virtual extension line L1 with the reference gradient B0 including the virtual extension line L0 to determine whether or not the detection gradient B1 is greater than the reference gradient B0. When YES is determined, the process proceeds to the next step S8, and when NO is determined, the process proceeds to another step S10.

  In step S8 described above, the ECU 4 estimates that the brake pads 18 and 19 are in a worn state in response to the detection gradient B1 being greater than the reference gradient B0, while in step S10 described above, the ECU 4 determines in step S7. In response to the NO determination, the processing is terminated after estimating that the brake pads 18 and 19 are in the non-wearing state.

After step S8, the process proceeds to step S9. In step S9, the ECU 4 operates the notification device 39 to notify the occupant (driver) of wear information of the brake pads 18, 19.
Here, when the notification lamp is employed as the notification device 39, the wear information is notified to the occupant by lighting or blinking of the notification lamp, and when the multi-information display is employed as the notification device 39, the multi-information display is displayed. When the vehicle-mounted speaker is used as the notification device 39, the wear information is notified to the vehicle occupant with sound.

  On the other hand, in step S11 described above, the ECU 4 compares the detection gradient B1 with the reference gradient B0 to determine whether or not the detection gradient B1 is larger than the reference gradient B0. If YES, the process proceeds to the next step S12. When NO is determined, the process proceeds to another step S14.

  In step S12 described above, the ECU 4 estimates that the brake pads 18 and 19 are in a worn state in response to the detection gradient B1 being greater than the reference gradient B0, while in step S14 described above, the ECU 4 performs step S11. In response to the NO determination, the processing is terminated after estimating that the brake pads 18 and 19 are in the non-wearing state.

  After step S12, the process proceeds to step S13. In step S13, the ECU 4 activates the notification device 39 to notify the occupant of wear information of the brake pads 18 and 19, and the process ends.

  As described above, the vehicle state estimation device of the above-described embodiment is the vehicle brake device including the hydraulic brake device (DSC device 2) and the electric brake device (EPB device 3), and the electric brake device (EPB device). 3) and a motor current value detection means (see motor current value detection unit 40) for detecting the gradient of the current value until the current output to the motor M reaches a peak value. The current value is a first gradient portion A that rises in the early stage of operation of the electric brake device (EPB device 3), and the first gradient portion A decreases from the peak value a to the base value b, and then a constant low current value is obtained. A constant value c to be maintained and a second gradient part B rising from the constant value c to the next peak value e, and a current value detection range of the motor current value detection means (motor current value detection unit 40) is , Of the second gradient part B Between the peak value e and the hydraulic brake device (DSC device 2) is inactive and the electric brake device (EPB device 3) is turned off. The operating means (see routine R1) to be operated and the current value detection gradient B1 during operation of the electric brake device (EPB device 3) are determined in advance as the reference gradient B0 of the current value when the brake pads are not worn. When the current value detection gradient B1 is larger than the reference gradient B0 based on the comparison result of the comparison means (see steps S7 and S11) and the comparison means (steps S7 and S11). Estimating means (see Steps S8 and S12) for estimating that the brake pads 18 and 19 are in a worn state (see FIGS. 2 to 5).

According to this configuration, the motor current value detection means (motor current value detection unit 40) detects the current value gradient B1 until the current output to the motor M reaches the peak value e.
The actuating means (routine R1) operates the electric brake device (EPB device 3) when the hydraulic brake device (DSC device 2) is inactive.
In the comparison means (steps S7 and S11), the detection gradient B1 of the current value during operation of the electric brake device (EPB device 3) is the reference gradient of the current value when the brake pad is worn without being determined in advance. It is compared whether it is larger than B0.
The above estimation means (see steps S8 and S12) indicates that the brake pads 18 and 19 are worn when the current value detection gradient B1 is larger than the reference gradient B0 based on the comparison result of the comparison means (steps S7 and S11). It is estimated that.

In this way, the reference gradient B0 of the current value when the brake pads that are not worn are mounted is compared with the detection gradient B1 of the current value in the vehicle in which the detected brake pads 18 and 19 to be worn are detected. Thus, when the detection gradient B1 is greater than the reference gradient B0, it is estimated that the brake pads 18 and 19 are in a worn state, so that the wear state of the brake pads 18 and 19 can be reliably estimated.
In addition, since the above-described estimation of the wear state is executed in a state where the hydraulic brake device (DSC device 2) is not operated, no pressure due to the hydraulic pressure is applied to the brake pads 18 and 19, and the brake is applied. The wear state of the pads 18, 19 can be accurately estimated.

  In one embodiment of the present invention, virtual extension lines L0 and L1 are respectively set along the reference gradient B0 and the detection gradient B1 (see FIGS. 4 and 5).

  According to this configuration, even if the reference gradient B0 and the detection gradient B1 are close to each other, the gap between the gradients B0 and B1 can be expanded by setting the virtual extension lines L0 and L1, and the expansion is performed. Since the wear state of the brake pads 18 and 19 can be estimated based on the size of the gap, the wear state can be easily estimated.

  In one embodiment of the present invention, the comparison means (step S8) compares the detection gradient B1 including the virtual extension lines L0 and L1 with the reference gradient B0 (see FIGS. 4 and 5).

  According to this configuration, it is possible to easily estimate the wear state of the brake pads 18 and 19 by comparing the gradients B1 and B0 of the current values without requiring high resolution.

  The notification device using the vehicle state estimation device according to the present invention is the vehicle state estimation device according to claim 1, wherein the brake pads 18 and 19 are in a worn state by the estimation means (see steps S8 and S12). When estimated, it is provided with a notification means 39 for notifying the occupant of wear information of the brake pads 18 and 19 (see FIGS. 3 and 4).

  According to this configuration, it is possible to notify the occupant (driver) of wear information of the brake pads 18 and 19 by the notification means 39 described above.

In the correspondence between the configuration of the present invention and the above-described embodiment,
The hydraulic brake device of the present invention corresponds to the DSC device 2 of the embodiment,
Similarly,
The electric brake device corresponds to the EPB device 3,
The motor corresponds to the electric motor M,
The motor current value detection means corresponds to the motor current value detection unit 40,
The operating means corresponds to the routine R1 by ECU control,
The comparison means corresponds to steps S7 and S11 by ECU control,
The estimation means corresponds to steps S8 and S12 by ECU control,
The present invention is not limited to the configuration of the above-described embodiment.

  For example, when the second gradient portion B is curved, a plurality of tangents may be obtained and the average value of each tangent may be used as the gradient. Further, the angle of the reference gradient B0 and the angle of the detection gradient B1 may be obtained, and the presence / absence of the wear state of the brake pads 18 and 19 may be estimated based on the difference between these angles.

  Further, a notification step for notifying the occupant that the brake pad is not worn may be provided next to steps S10 and S14 in FIG. 4 so that the occupant is also notified of the non-wearing state of the brake pad.

  As described above, the present invention relates to a vehicle state estimation device that electrically estimates a wear state of a brake pad in a vehicle braking device including a hydraulic brake device and an electric brake device, and uses the same. This is useful for the alarm device.

2 ... DSC device (hydraulic brake device)
3 ... EPB device (electric brake device)
18, 19 ... Brake pad 39 ... Notification device 40 ... Motor current value detection unit (motor current value detection means)
a ... peak value b ... base value c ... constant part e ... peak value A ... first slope part B ... second slope part B0 ... reference slope B1 ... detection slopes L0, L1 ... virtual extension line M ... electric motor (motor)
R1 ... Actuating means
S5: Determination means S7, S11 ... Comparison means S8, S12 ... Estimation means

Claims (2)

In a vehicle braking device including a hydraulic brake device and an electric brake device,
A motor for driving the electric brake device;
Motor current value detection means for detecting the gradient of the current value until the current output to the motor reaches a peak value,
The current value includes a first gradient portion that rises in the initial stage of operation of the electric brake device, a constant portion that the first gradient portion decreases from a peak value to a base value, and then maintains a constant low current value, and the constant value A second gradient part rising from the part to the next peak value,
The detection range of the current value of the motor current value detection means is between the base value and the peak value of the second gradient part,
An operating means for operating the electric brake device in a non-operating state of the hydraulic brake device;
Comparison means for comparing whether or not a current value detection gradient during operation of the electric brake device is larger than a reference gradient of a current value when a brake pad that is not worn is obtained in advance.
An estimation means for estimating that the brake pad is in a worn state when a current value detection gradient is larger than a reference gradient based on a comparison result of the comparison means ;
Determining means for determining whether or not the detected gradient in the second gradient portion of the motor current value is close to a reference gradient;
When it is determined by the determining means that a virtual extension line needs to be set,
A virtual extension line is set along each of the reference gradient and the detection gradient,
The vehicle state estimating device for comparing the detected gradient including the virtual extension line with a reference gradient . The vehicle state estimation device according to claim 1,
A notification device using a vehicle state estimation device provided with notification means for notifying an occupant of wear information on a brake pad when the estimation means estimates that the brake pad is in a wear state.

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