JPH10329681A - Braking force control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the brake squeal while ensuring a required total braking force in a braking force control device having a hydraulic braking means and a regenerative braking means. SOLUTION: In this device, when a brake squeal detection signal S exceeds a prescribed value S0 (time t1 ), generation of brake squeal is prevented by changing hydraulic braking force FL, and total braking force FALL is kept constant by changing regenerative braking force FG so as to compensate the change of hydraulic braking force FL. When regenerative margin FGmargin is smaller than a prescribed value F0 so that regenerative braking force FG can not be sufficiently increased at the time t1 , hydraulic braking force FL is increased. Thus, in such a case, the change of hydraulic braking force FL can be surely compensated by regenerative braking force FG.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force control device having regenerative braking means and hydraulic braking means, and more particularly to a braking force control device suitable for preventing brake squeal of a hydraulic braking means.

[0002]

2. Description of the Related Art Conventionally, a hydraulic braking device has been widely used as a vehicle braking device. The hydraulic braking device generates a hydraulic braking force by pressing a friction member with a brake hydraulic pressure on a rotor that rotates with the wheels. In the hydraulic braking device, when a braking force is generated, an unpleasant abnormal noise of a high frequency, that is, a brake squeal may be generated due to frictional vibration between the rotor and the friction member. As a braking force control device capable of preventing the occurrence of such brake squeal, a configuration disclosed in, for example, Japanese Patent Application Laid-Open No. 62-122856 is conventionally known.

[0003] The above-mentioned conventional braking force control device includes an auxiliary braking device in addition to a main braking device which is a hydraulic braking device. If brake squeal is detected by the main braking means,
Braking force generated by main braking means (hereinafter referred to as main braking force)
Is reduced, and the braking force generated by the sub braking means (hereinafter, referred to as sub braking force) is increased by the reduced amount. Generally, brake squeal is likely to occur when the hydraulic braking force is within a specific area. Therefore, according to the conventional braking force control device, when the brake squeal is detected, the main braking force is reduced and deviates from the specific area, thereby preventing the occurrence of the brake squeal. In addition, the sum of the main braking force and the sub braking force, that is, the total braking force is kept constant by increasing the sub braking force by the decrease in the main braking force.

[0004]

In the above-described conventional braking force control device, if a hydraulic braking device is used as the auxiliary braking device, there is a possibility that brake noise will occur in the auxiliary braking device when the auxiliary braking force is increased. There is. Therefore, in the above-described conventional apparatus, it is desirable to use a braking device other than the hydraulic braking device as the auxiliary braking means in order to reliably prevent the occurrence of brake squeal.

[0005] For example, in an electric vehicle, a regenerative braking device is generally used as a braking device other than the hydraulic braking device. The regenerative braking device generates regenerative braking force by supplying regenerative energy generated by rotation of a motor drive wheel to a battery as a charging current. Therefore, the maximum regenerative braking force that the regenerative braking device can generate is limited by the maximum amount of regenerative energy that the battery can accept.

For this reason, in the above-mentioned conventional apparatus, when a regenerative braking device is employed as the auxiliary braking means, the auxiliary braking force is sufficiently increased in a situation where a regenerative braking force close to the maximum regenerative braking force is generated. It is not possible. If a brake squeal occurs in the main braking means in such a situation, even if the main brake force is reduced to prevent the brake squeal, the auxiliary brake force may not be increased by the reduced amount. In this case, the total braking force cannot be maintained at a required level.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and in a braking force braking device having a hydraulic braking means and a regenerative braking means, a brake noise is ensured while securing a total braking force to a required magnitude. The purpose is to prevent the occurrence of.

[0008]

The above object is achieved by the present invention.
As described in the above, in a braking force control device including a hydraulic braking unit that generates a hydraulic braking force and a regenerative braking unit that generates a regenerative braking force, a brake squeak detecting unit that detects a brake squeal of the hydraulic braking unit, From the maximum regenerative braking force that can be generated by the regenerative braking means, a regenerative margin calculating means for obtaining a regenerative margin by reducing a regenerative braking force generated when a brake squeal is detected, and when a brake squeal is detected. If the regenerative margin is less than a predetermined value, the hydraulic braking force is increased and the regenerative braking force is reduced in accordance with the increase. If the regenerative margin is equal to or greater than the predetermined value, the hydraulic braking force is increased. This is achieved by a braking force control device including: brake squeal prevention means for reducing the power and increasing the regenerative braking force in accordance with the reduction.

In the present invention, the brake squeal preventing means increases or decreases the hydraulic braking force when the brake squeal is detected. Generally, brake squeal occurs in a specific area of hydraulic braking force. Therefore, when brake squeal is detected, the hydraulic braking force is increased or decreased,
The occurrence of brake squeal is prevented. Further, the regenerative braking force is reduced or increased by the increase or decrease of the hydraulic braking force, so that the sum of the hydraulic braking force and the regenerative braking force, that is, the total braking force is kept constant. By the way, when the regenerative margin is less than the predetermined value, the regenerative braking force cannot be sufficiently increased. On the other hand, according to the present invention, when the regenerative margin is less than the predetermined value, the hydraulic braking force is increased,
The regenerative braking force is reduced. Therefore, when the hydraulic braking force is changed, the total braking force is reliably kept constant.

[0010]

FIG. 1 shows a system configuration diagram of a braking force control device according to an embodiment of the present invention. The braking force control device according to the present embodiment includes an electronic control unit 12 for braking control (hereinafter, referred to as a brake ECU 12). A drive / regeneration device 14 is connected to the brake ECU 12.

The drive / regeneration device 14 has a drive motor. In the system of the present embodiment, the left and right front wheels FL,
FR is a driving wheel, and left and right rear wheels RR and RL are non-driving wheels. FIG. 1 shows only the left and right front wheels FL and FR that are drive wheels. The rotors of the drive motors are connected to the left and right front wheels FL and FR via drive shafts 20 and 21 and a gear mechanism (not shown), respectively. Accordingly, the left and right front wheels FL and FR are provided with the drive shaft 2 respectively.
The driving force generated by the driving motor is transmitted via 0 and 21.

A battery 24 is connected to the drive motor. The drive motor generates a drive torque according to the electric power supplied from the battery 24, and generates the left and right front wheels FL,
It has a function of generating regenerative energy using the torque input from the FR as a power source. Inside the drive motor, a magnetic field generating mechanism for generating a magnetic field of a predetermined strength, and
There is a built-in coil that rotates across the magnetic field.
The magnetic field generated by the magnetic field generation mechanism is the brake EC
It changes according to the command signal supplied from U12. Further, the magnetic field and the coil rotate relatively when the wheel rotates.

The magnitude of the regenerative energy generated by the drive motor depends on the strength of the magnetic field generated by the magnetic field generating mechanism and the relative rotational speed between the magnetic field and the coil, that is, the wheel speed of the left and right front wheels FL and FR. Will be a value corresponding to. Therefore,
The magnitude of the regenerative energy changes according to the value of the command signal supplied from the brake ECU 12. When the drive motor generates regenerative energy, a regenerative torque is applied to the left and right front wheels FL and FR so as to brake the rotation. That is, the regenerative torque generated by the drive motor acts as a braking force on the left and right front wheels FL and FR. Hereinafter, the braking force generated by the regenerative torque, referred to as regenerative braking force F _G.

The regenerative energy generated by the drive motor is
It is supplied to the battery 24 as a charging current. Therefore, the greater the regenerative torque is generated, the more the battery 24
Is charged with a large charging current. The upper limit of the regenerative energy that the battery 24 can accept is the battery 2
4 is limited by various conditions such as the state of charge. Therefore,
The upper limit of the regenerative braking force F _G is limited to a size corresponding to the upper limit of the regenerative energy. Hereinafter referred to as the maximum regenerative braking force F _Gmax the upper limit of the regenerative braking force F _G.

The braking force control device according to the present embodiment also includes a hydraulic control mechanism 32. The hydraulic control mechanism 32 includes a master cylinder 34. A brake pedal 36 is connected to the master cylinder 34. Master cylinder 3
A hydraulic pressure (hereinafter, referred to as a master cylinder pressure) corresponding to the amount of operation applied to the brake pedal 36 is generated at 4.
A hydraulic actuator 38 is connected to the master cylinder 34. The hydraulic actuator 38 is a brake ECU
The brake ECU 12 generates a brake hydraulic pressure according to a command signal given from the brake ECU 12. Wheel cylinders of each wheel communicate with the hydraulic actuator 38. Therefore, a hydraulic pressure corresponding to the brake hydraulic pressure generated by the hydraulic actuator 38 is supplied to each wheel cylinder.

The wheel cylinder drives the calipers 40 and 41 with a force corresponding to the oil pressure. When the calipers 40 and 41 are driven, the brake pads mounted on the calipers 40 and 41 are moved toward the braking surfaces of the brake rotors 42 and 43 with the force corresponding to the oil pressure of the wheel cylinder. Is pressed. Therefore, the brake ECU 1
2, a braking force of a magnitude corresponding to the command signal applied to the hydraulic control mechanism 32 is applied to each wheel. Hereinafter, the braking force by the hydraulic control mechanism 32 is generated, referred to as hydraulic braking force F _L.

The calipers 40 and 41 have an acceleration sensor 4
4, 45 are attached. Of the acceleration sensors 44 and 45
The output signal is supplied to the brake ECU 12. Blur
The ECU 12 receives the output signals of the acceleration sensors 44 and 45
Based on this, the vibration of the calipers 40 and 41 is detected. Above
In the system of the present embodiment, the left and right wheels FL,
FR includes a regenerative braking force F generated by the drive / regeneration device 14.
_GAnd the hydraulic braking force F generated by the hydraulic control mechanism 32_LWith
Both are granted. The left and right rear wheels RL, RR
Pressure braking force F _LOnly is given. In the following, regenerative braking
Force F_GAnd hydraulic braking force F_LAnd the total braking force F_ALLCall
You.

The hydraulic actuator 38 has a master pressure sensor for detecting a master cylinder pressure. The output signal of the master pressure sensor included in the hydraulic actuator 38 is
It is supplied to the brake ECU 12. Brake ECU
12 is a braking force to be generated in the vehicle based on the output signal of the master pressure sensor, that is, a required braking force F
Calculate _REQ . The brake ECU12 is allocated appropriately required braking force F _REQ to the regenerative braking force F _G and the hydraulic braking force F _L, as required regenerative braking force and F _G and hydraulic braking force F _L is generated, The drive signal supplied to the drive / regeneration device 14 and the hydraulic control mechanism 32 is controlled.

Next, referring to FIG.
Will be described. FIG. 2 is a configuration diagram of the hydraulic control mechanism 32. As shown in FIG. 2, the hydraulic control mechanism 32 includes a pump 46. The pump 46 is driven by a motor 48. A reservoir tank 50 communicates with a suction port of the pump 46. The discharge port of the pump 46 communicates with a high-pressure passage 54 leading to the regulator 52. High pressure passage 5
An accumulator 56 communicates with 4. The accumulator 56 stores the brake fluid discharged from the pump 46.

A main hydraulic passage 58 communicates with the regulator 52. The regulator 52 reduces the hydraulic pressure of the accumulator 56 supplied from the high-pressure passage 54 to a predetermined regulator pressure _PRE and outputs it to the main hydraulic passage 58. The main hydraulic passage 58 is provided with a hydraulic pressure sensor 60 for detecting the regulator pressure _PRE and a pressure increase control valve 62. The output signal of the oil pressure sensor 60 is supplied to the brake ECU 12. The brake ECU 12 is provided with the hydraulic sensor 6
The regulator pressure _PRE is detected based on the 0 output signal.

The pressure increase control valve 62 is a linear control valve that changes the conduction state of the main hydraulic passage 58. The pressure increase control valve 62 changes its opening in accordance with a drive signal supplied from the ECU 12. In the main hydraulic passage 58, a check valve 64 that allows only the flow of the fluid from the downstream side of the pressure increase control valve 62 to the regulator 52 side is arranged in parallel with the pressure increase control valve 62.

In the main hydraulic passage 58 downstream of the pressure increasing control valve 62, a pressure reducing passage 6 leading to an auxiliary reservoir tank 66 is provided.
8 are in communication. The pressure reduction control valve 7 is provided in the pressure reduction passage 68.
0 is provided. The pressure reduction control valve 70 is a linear control valve that controls the conduction state of the pressure reduction passage 68. The pressure reduction control valve 70 changes its opening in accordance with a drive signal supplied from the brake ECU 12. Decompression passage 6
8, a check valve 72 is disposed in parallel with the pressure reduction control valve 70 to allow only a fluid flow from the auxiliary reservoir tank 66 toward the main hydraulic passage 58.

The main hydraulic passage 58 is provided on the downstream side of the pressure increase control valve 62 with the wheel cylinders 7 on the rear wheels RL and RR.
4 and 76 are communicated with a rear wheel side hydraulic passage 78. The rear wheel side hydraulic passage 78, the rear-wheel-side hydraulic passage 78 inside the hydraulic, i.e., the oil pressure sensor 80 for detecting the rear-wheel brake hydraulic pressure P _r is disposed. The output signal of the oil pressure sensor 80 is supplied to the brake ECU 12. Brake E
CU12 is configured to detect the rear-wheel brake hydraulic pressure P _R based on the output signal of the oil pressure sensor 80, the rear-wheel brake hydraulic pressure by changing the drive signal supplied to said pressure-increasing control valves 62 and the pressure reduction control valve 70 to control the P _R.

A rear wheel side holding valve 82 and a proportioning valve 84 are arranged in the rear wheel side hydraulic passage 78 in order from the upstream side. The rear wheel side holding valve 82 is a normally open electromagnetic opening / closing valve, and is closed by receiving an ON signal from the brake ECU 12. When the hydraulic pressure supplied from the rear-wheel hydraulic passage 78 is equal to or less than a predetermined value, the proportioning valve 84 supplies the hydraulic pressure to the wheel cylinders 74 and 76 as it is, while supplying the hydraulic pressure from the rear-wheel hydraulic passage 78. When the hydraulic pressure exceeds a predetermined value, the hydraulic pressure is reduced at a predetermined ratio and supplied to the wheel cylinders 74 and 76.

The rear wheel side holding valve 8 for the rear wheel side hydraulic passage 78
2 and the proportioning valve 84,
A rear wheel side pressure reducing passage 86 leading to the reservoir tank 50 is in communication. A rear wheel side pressure reducing valve 88 is provided in the rear wheel side pressure reducing passage 86.
Are arranged. The rear wheel side pressure reducing valve 88 is a normally closed electromagnetic opening / closing valve, and is opened by receiving an ON signal from the brake ECU 12.

A front-wheel-side hydraulic passage 90 communicates with the rear-wheel-side hydraulic passage 78 upstream of the rear-wheel-side holding valve 82. A switching valve 92 is provided in the front-wheel-side hydraulic passage 90. The switching valve 92 is a normally closed electromagnetic opening / closing valve, and is opened by receiving an ON signal from the brake ECU 12. The front-wheel-side hydraulic passage 90 on the downstream side of the switching valve 92, the interior of the hydraulic pressure of the front wheel hydraulic passage 90, i.e., the oil pressure sensor 91 for detecting the front-wheel brake hydraulic pressure P _F is disposed. The output signal of the oil pressure sensor 91 is supplied to the brake ECU 12. Brake E
CU12 detects the front-wheel brake hydraulic pressure P _F based on the output signal of the oil pressure sensor 91.

On the downstream side of the switching valve 92, a front wheel side hydraulic passage 90 leads to a left front wheel hydraulic passage 96 leading to a left front wheel wheel cylinder 94, and a right front wheel wheel cylinder 98.
To the right front wheel hydraulic passage 100. In the left front wheel hydraulic passage 96 and the right front wheel hydraulic passage 100, respectively,
A left front wheel holding valve 102 and a right front wheel holding valve 104 are provided. The left front wheel holding valve 102 and the right front wheel holding valve 104 are both normally open electromagnetic open / close valves, and are closed when an ON signal is given from the brake ECU 12.

Left front wheel holding valve 1 of left front wheel hydraulic passage 96
02 and a wheel cylinder 94, and a portion of the right front wheel hydraulic passage 100 between the right front wheel holding valve 104 and the wheel cylinder 98, a left front wheel decompression passage 106 and a right front wheel decompression passage 108, respectively. Communicating. The left front wheel decompression passage 106 and the right front wheel decompression passage 108 are both
It communicates with the reservoir tank 50. Left front wheel decompression passage 1
06 and the front right wheel pressure reduction passage 108 are provided with a front left wheel pressure reduction valve 110 and a front right wheel pressure reduction valve 112, respectively. Both the left front wheel pressure reducing valve 110 and the right front wheel pressure reducing valve 112 are normally closed electromagnetic opening / closing valves, and are opened by receiving an ON signal from the brake ECU 12.

The master cylinder 34 has a master pressure passage 1
14 are in communication. In the master pressure passage 114, a hydraulic pressure sensor 116 for detecting a master cylinder pressure PM _{/ C} is provided. The output signal of the oil pressure sensor 116 is the brake EC
U12. The brake ECU 12 determines the master cylinder pressure P based on the output signal of the hydraulic pressure sensor 116.
Detect _{M / C.} A stroke simulator 118 is provided in the master pressure passage 114.

In the master pressure passage 114, a left front wheel master pressure passage 120 leading to the left front wheel wheel cylinder 94, and
A right front wheel master pressure passage 122 leading to the right front wheel cylinder 98 communicates therewith. Switching valves 124 and 126 are provided in the left front wheel master pressure passage 120 and the right front wheel master pressure passage 122, respectively. Switching valve 124
Reference numerals 126 and 126 denote normally open electromagnetic on / off valves, which are closed when an ON signal is given from the brake ECU 12.

In this embodiment, when the system is normal without any abnormality, the switching valves 124 and 126 are both closed at the same time as the brake pedal 36 is depressed. For this reason, the brake fluid flowing out of the master cylinder 34 is normally supplied to the wheel cylinders 94 and 9 under normal conditions.
8 does not flow. In this case, the brake pedal 3
When the master cylinder pressure P _{M / C} rises due to the depression of the brake pedal 6, the brake fluid in the master cylinder 34 flows into the stroke simulator 118. Also,
When the depression of the brake pedal 36 is released and the master cylinder pressure P _{M / C} decreases, the stroke simulator 1
The brake fluid in 18 flows into the master cylinder 34. Therefore, according to the stroke simulator 118, it is possible to cause the brake pedal 36 to generate a stroke corresponding to the pedal depression force in a state where the switching valves 124 and 126 are closed.

When it is detected that an abnormality has occurred in the system, both the switching valves 124 and 126 are opened. In this case, the wheel cylinders 94, 9 on the front wheel side
The communication between the master cylinder 34 and the master cylinder 34 ensures that the hydraulic pressure of the wheel cylinders 94 and 98 is increased up to the master cylinder pressure PM _{/ C.} Next, the operation of the hydraulic control mechanism 32 will be described. In the hydraulic control mechanism 32, when the brake pedal 36 is depressed and there is no tendency to lock any of the wheels, during normal braking, the rear wheel holding valve 82, the rear wheel pressure reducing valve 88, the left front wheel holding valve 102, The right front wheel holding valve 104, the left front wheel pressure reducing valve 110, and the right front wheel pressure reducing valve 112 are turned off and the switching valves 92, 124, 12
6 is turned on. Hereinafter, this state is referred to as a normal brake state.

In the normal brake state, the rear wheel hydraulic passage 78, the front wheel hydraulic passage 90, the left front wheel hydraulic passage 96,
And to the right front wheel hydraulic passage 100 is conductive, the hydraulic pressure of the main hydraulic passage 78, i.e., the rear-wheel brake hydraulic pressure P _R, together are guided to the front wheel side wheel cylinder 94, 98, proportioning valve 84 Through the wheel cylinders 74 and 76 on the rear wheel side. In normal braking condition, the brake ECU12 is rear-wheel brake hydraulic pressure P _R and the front-wheel brake hydraulic pressure P _F is the required braking force F
So that a value corresponding to the hydraulic braking force F _L which is determined based on the _REQ and regenerative braking force F _G, the pressure increasing control valve 62
And a drive signal applied to the pressure reduction control valve 70 is controlled.

When it is detected that any of the wheels has a tendency to lock, ABS control is started for that wheel. For example, when it is detected that the left front wheel FL has a tendency to lock, the ABS control is started for the left front wheel FL. The ABS control for the front left wheel FL is realized by opening and closing the front left wheel holding valve 102 and the front left pressure reducing valve 110 in the normal braking state.

In the normal braking state, the left front wheel holding valve 102 is closed and the left front wheel pressure reducing valve 11 is closed.
When 0 is opened, the wheel cylinder 94 communicates with the reservoir tank 50. In this case, the brake fluid flows out of the wheel cylinder 94 to the reservoir tank 50, so that the oil pressure of the wheel cylinder 94 is quickly reduced.
This state is hereinafter referred to as a decompression mode.

Depending on the pressure reduction mode, the wheel cylinder 94
When the left front wheel holding valve 102 is opened and the left front wheel pressure reducing valve 110 is closed in a state where the hydraulic pressure is reduced, the wheel cylinder 94 communicates with the main hydraulic passage 78. Therefore, the hydraulic pressure of the wheel cylinder 94 is raised toward the rear-wheel brake hydraulic pressure P _R. Hereinafter, this state,
This is called a pressure increase mode.

When both the left front wheel holding valve 102 and the left front wheel pressure reducing valve 110 are closed, the wheel cylinder 94 is shut off from the hydraulic actuator 38. Therefore, the oil pressure of the wheel cylinder 94 is maintained. This state is hereinafter referred to as a holding mode. The ABS control of the left front wheel FL is executed by switching between the pressure-reducing mode, the pressure-increasing mode, and the holding mode so that the slip ratio of the wheel is kept below a predetermined threshold value. Similarly, in the ABS control of the right front wheel FR, the pressure reduction mode, the pressure increase mode, and the holding mode are appropriately switched and formed according to the open / close state of the right front wheel holding valve 104 and the right front wheel pressure reducing valve 112. Is achieved. The rear-wheel-side ABS control is executed commonly for the left and right rear wheels RL and RR by switching the rear-wheel holding valve 82 and the rear-wheel pressure reducing valve 88.

Incidentally, as described above, the hydraulic braking force F
_L is generated when the brake pads of the calipers 40, 41 are pressed by the disk rotors 42, 43.
When the disk rotors 42 and 43 and the brake pads slide while being pressed, a brake squeal may occur due to vibration caused by the frictional energy. Resulting ease of brake noise is also changed depending on conditions such as the state of wear of the rotational speed and the brake pads of the disc rotor 42 and 43, mainly depends on the magnitude of the hydraulic braking force F _L.

[0039] That is, as the hydraulic braking force F _L is large,
By increasing the pressing force between the disk rotors 42 and 43 and the brake pad, the friction energy generated between the two increases. Therefore, as the hydraulic braking force F _L is large, the brake noise is likely to be excited. On the other hand, when a pressing force acts between the disk rotors 42 and 43 and the brake pad, the vibrations of both are suppressed and a vibration damping effect is produced. Therefore, the greater the hydraulic braking force _FL is, the greater the vibration damping effect is, thereby suppressing the occurrence of brake squeal.

[0040] Figure 3 shows the relationship between the frequency of the hydraulic braking force F _L and brake noise by a solid line and the hydraulic braking force F
The relationship between _L and the degree of excitation of brake squeal due to frictional energy and the degree of suppression of brake squeal due to the vibration suppression effect are indicated by broken lines, respectively. As shown by the broken line in FIG. 3, according to an increase of the hydraulic braking force F _L, one brake squeal which is easy to be excited by an increase of frictional energy, the generation of brake noise is suppressed by increasing the damping effect. Thus, the excitation of the brake noise due to the increase of friction energy that acts contradictory that inhibition of brake noise by increasing the damping effect is superimposed, as shown by the solid line in FIG. 3, the hydraulic braking force F _L intermediate In a region (region A shown in FIG. 3; hereinafter referred to as a squeal occurrence region), the frequency of occurrence of brake squeal is high.

[0041] Therefore, when the brake noise is detected, the hydraulic pressure braking force F _L is increased or decreased, by removing from the squeaking regions hydraulic braking force F _L, it is possible to prevent the occurrence of brake noise. At the same time varying the hydraulic braking force F _L, by the change alters the regenerative braking force F _G to be compensated, it is possible to maintain the total braking force F _ALL constant.

[0042] In this case, better hydraulic braking force F _L is small,
Hydraulic control mechanism 3 such as reduced wear of brake pads
8 is advantageous in that durability can be improved. Further, it regenerative braking force F _G is large, the advantage capable of securing a large regenerative energy. Therefore, from these perspectives,
To prevent brake squeal, it can be said that those who increase the regenerative braking force F _G while decreasing the hydraulic pressure braking force F _L is desirable.

[0043] However, as described above, the upper limit of the regenerative braking force F _G of the driving and regeneration device 14 may occur is limited by the maximum regenerative braking force F _Gmax. Therefore, when the brake noise is detected, constantly, when reducing the hydraulic braking force F _L, when the regenerative braking force F _G is generated close to the maximum regenerative braking force F _Gmax at that time, Hydraulic braking force F
_L decrease in not only can increase the regenerative braking force F _G. In this case, the total braking force F _ALL cannot be maintained at a required level.

The brake force control apparatus of the present embodiment, when the brake noise is detected, that on the basis of the magnitude of the regenerative braking force F _G which is generated at that time increases or decreases the hydraulic braking force F _L This is characterized in that it is possible to prevent the occurrence of brake squeal while securing the required total braking force F _ALL . When the brake squeal occurs, high-frequency vibration of a specific frequency band is generated in the calipers 40 and 41. Therefore, in the present embodiment, a signal component (hereinafter, referred to as a brake squeak detection signal S) in the above-mentioned frequency band is extracted by filtering output signals of the acceleration sensors 44, 45 attached to the calipers 40, 41, when the brake noise detection signal S exceeds a predetermined threshold value S _0, it is set to determine that the brake noise has occurred.

The vibration of the calipers 40 and 41 occurs prior to the occurrence of brake squeal. Accordingly, by appropriately selecting the threshold S ₀ regarding brake noise detection signal S, it is also possible to foresee the brake noise to that just before the occurrence. In the following description, detecting brake squeal shall include predicting brake squeal immediately before its occurrence.

FIG. 4 shows a braking force control apparatus according to this embodiment.
The brake squeal detection signal S and the regenerative braking force F_GWhen
Hydraulic braking force F_LOf the distribution with respect to time. What
FIG. 4 shows the regenerative braking force F_GAnd hydraulic braking force F_LArrangement with
The maximum regeneration for the minute is when the brake squeal is detected.
Braking force F_GmaxRegenerative braking force F close to_GWhere is occurring
And the maximum regenerative braking force F_GmaxEnough than
Small regenerative braking force F _GIf a dashed line has occurred
, Respectively.

As shown in FIG.₁In the blur
Squeak detection signal S is threshold value S₀Is higher than
Rake squeal is detected. Time t₁Occurred in
Regenerative braking force F_GAnd the maximum regenerative braking force F_GmaxDifference with
(Hereafter, regenerative margin F_GmarginIs a predetermined value F₀Less than
If it is above (indicated by a broken line in FIG. 4), the time t ₁
Thereafter, the hydraulic braking force F_LIs reduced and the decrease
Only regenerative braking force F_GIs increased. Therefore, the total braking force
F_ALLIs the time t₁Thereafter, it is kept constant.

[0048] Here, the predetermined value F _0, in order to prevent the occurrence of brake noise, i.e., the hydraulic braking force required for changing the brake noise generation region outside from the hydraulic braking force squeal the F _L generation area F It is set to match the decrease width of _L. Therefore, if the regeneration margin F _{Gmargi n} is a predetermined value F ₀ or more, the hydraulic braking force F _L to the brake noise is stopped
It is decreased and it is ensured that may increase its only decrease the regenerative braking force F _G.

On the other hand, at time t ₁ , regeneration margin F
In the case _Gmargin is less than the predetermined value F ₀ (the case shown by the solid line in FIG. 4), the brake noise reducing hydraulic braking force F _L to a stop, the regenerative braking force F _G, hydraulic braking force F
It may not be possible to increase _{L by} the decrease. So, in this case, the time t ₁ after, the hydraulic braking force F
_L is increased, and the regenerative braking force F _G
There it is reduced, the total braking force F _ALL is kept constant at time t ₁ later.

Time t₁At the hydraulic braking force F_LIncreases
The hydraulic braking force F _LIs the squealing area
The brake squeal detection signal S
To decrease. And time t_TwoIn, brake squeal
When the detection signal S is equal to the threshold value S₁Below, brake squeal
It is determined that it has stopped. Therefore, the time t_TwoAt
Hydraulic braking force F_LAnd regenerative braking force F_GChanges are aborted,
Thereafter, both are kept constant.

[0051] Thus, brake squeal by hydraulic braking force at the same time the brake squeal is detected F _L is increased or decreased is stopped promptly, thereby, the occurrence of brake squeal is effectively prevented . Also, the hydraulic braking force F _L
To compensate for the increase or decrease in, that the regenerative braking force F _G is changed, the total braking force F _ALL is kept constant.

[0052] As described above, in the present embodiment, on the basis of the magnitude relationship between the regeneration margin F _Gmargin a predetermined value F ₀ at the time the brake noise is detected, increase or decrease the hydraulic braking force F _L Is determined. Therefore, regenerative margin F _Gmargin is small, if it can not be increased sufficiently the regenerative braking force F _G can also be reliably compensate for changes in the hydraulic braking force F _L by the regenerative braking force F _G.
Therefore, according to the brake force control apparatus of the present embodiment, it is possible to prevent the occurrence of brake noise while securing a required total braking force F _ALL.

[0053] Incidentally, the regenerative braking force F _G, rather than being generated by frictional force, in which electrically generated. Therefore, it can not happen that the brake noise is generated due to changing the regenerative braking force F _G. The above functions of the braking force control device of the present embodiment are realized by the brake ECU 12 executing a predetermined routine. Hereinafter, with reference to FIG.
The contents of the routine executed by the program 12 will be described. FIG. 5 is a flowchart of a routine executed by the brake ECU 12 in the present embodiment. The routine shown in FIG. 5 is a regular interruption routine started at regular time intervals.

When the routine shown in FIG. 5 is started, first, the processing of step 200 is executed. Step 20
In 0, brake noise detection signal S whether larger than the threshold value S ₀ is determined. As a result, if S> S ₀ is not satisfied, it is determined that no brake squeal has occurred, and the process of step 200 is executed again. on the other hand,
If in step 200 S> S ₀ is established, the process of step 202 is performed.

In step 202, the currently generated
Regenerative braking force F_GAnd the maximum regenerative braking force F _GmaxDifference (F_Gmax
-F_G), Ie, the regenerative margin F_GmarginIs calculated
You. When the processing of step 202 is completed, the next step is
In the step 204, the regenerative margin F_GmarginIs the predetermined value F₀
It is determined whether the difference is less than or equal to. As a result, F_Gmargin
<F₀Holds until brake squeal stops.
Hydraulic braking force F_LIs reduced, the regenerative system
It is determined that it may not be possible to increase the power
You. In this case, next, in step 206, the hydraulic braking
Force F_LIs increased by a predetermined amount.
Hydraulic braking force F_LBraking force F by the increment of _GIs reduced
You. When the processing of step 208 is completed, the next step is
In step 210, the brake noise detection signal S
Value S₁Is determined. As a result, S <
S₁If is not established, brake squeal still stops
It is determined that they do not exist, and thereafter, after step 206
Is performed. On the other hand, in step 208, S
<S₁Holds, it is determined that the brake squeal has stopped.
Then, the current routine is terminated. Therefore, step
Hydraulic braking force F at step 206_LProcessing to increase the
Regenerative braking force F at step 208_GThe process to reduce
It is repeatedly executed until the brake squeal stops.

On the other hand, in step 204, F
If _Gmargin <F ₀ is not satisfied, even to reduce the hydraulic braking force F _L to prevent brake squeal, it is determined that it is possible to increase the regenerative braking force by the decrease. In this case, next, at step 212, the hydraulic braking force F _L
There is reduced a predetermined amount, decrease only the regenerative braking force F _G of the hydraulic braking force F _L at the next step 214 is increased. When the process of step 214 is completed, the process proceeds to step 2
At 16, the brake squeal detection signal S reaches the threshold value S _1.
Is determined. As a result, if S <S ₁ is not satisfied, it is determined that the brake squeal has not been stopped yet, and the processes after step 212 are executed again. On the other hand, if S <S ₁ is satisfied in step 216, the brake squeal is terminated this routine is determined to be stopped. Therefore, step 212
Process for reducing the hydraulic braking force F _L at, and Step 2
Process for increasing the regenerative braking force F _G at 14, brake squeal is repeatedly executed until it stops.

[0057] In the above embodiment, based on the output signal of the acceleration sensor 44, it is assumed that detects brake noise, the present invention is not limited to this, the hydraulic braking force F _L Brake squeal may be detected based on whether or not is within the squeal occurrence region. That is, as described above, since the brake noise is considered to occur when in the hydraulic braking force F _L is squeaking region, without detecting the vibration of the caliper 40 and 41, on the basis of the hydraulic braking force F _L Brake The occurrence of squeal can also be estimated.

Further, in the above-described embodiment, the regenerative braking force cannot be generated for the rear wheels RL and RR which are non-drive wheels. However, even when brake squealing occurs on the rear wheels RL and RR, the regenerative margin F _Gmargin and the predetermined value F
The hydraulic braking force F of the rear wheels RL and RR according to the magnitude relationship with ₀
With increasing or decreasing _L, and the taking into account the load distribution between the front and rear wheels, the rear wheels RL, the front wheels FL to compensate for changes in the hydraulic braking force F _L of the RR side, the regenerative braking force F _G of the FR side By making the change, it is possible to prevent the occurrence of brake squeal while securing the braking force of the entire vehicle.

In the above-described embodiment, the hydraulic control mechanism 32 is provided with the drive / regeneration device 14
The braking ECU 12 executes step 200 of the routine shown in FIG. 5 by the regenerative braking means, and the brake squeal detecting means
The regenerative margin calculating means executes step 2
By executing steps 04 to 216, the above-described brake squeal prevention means is realized.

[0060]

As described above, according to the present invention, a change in hydraulic braking force for preventing brake noise can be reliably compensated for by a change in regenerative braking force. Therefore,
ADVANTAGE OF THE INVENTION According to the braking force control apparatus which concerns on this invention, generation | occurrence | production of a brake squeal can be prevented, ensuring the required total braking force.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a braking force control device according to an embodiment of the present invention.

FIG. 2 is a system configuration diagram of a hydraulic control mechanism of the present embodiment.

[3] The relation between brake noise frequency for the hydraulic braking force F _L, the degree of excitation of the brake noise due to friction energy, and illustrates with the degree of suppression of brake noise by damping effect.

FIG. 4 shows a brake squeal detection signal and a hydraulic braking force _FL.
And is a diagram illustrating the time change of the distribution between the regenerative brake force F _G.

FIG. 5 is a flowchart of a routine executed by a brake ECU in the embodiment.

[Explanation of symbols]

 12 Brake ECU 14 Drive / regeneration device 32 Hydraulic pressure generating mechanism 40, 41 Caliper 44, 45 Acceleration sensor

Claims (1)

[Claims] 1. A hydraulic braking means for generating a hydraulic braking force,
In a braking force control device including regenerative braking means for generating regenerative braking force, brake squeal detection means for detecting brake squeal of the hydraulic braking means, and brake squealing based on a maximum regenerative braking force that the regenerative braking means can generate. A regenerative margin calculating means for obtaining a regenerative margin by reducing a regenerative braking force generated when a brake noise is detected; and, when a brake squeal is detected, when the regenerative margin is less than a predetermined value, a hydraulic control is performed. When the power is increased, the regenerative braking force is reduced according to the increase, and when the regenerative margin is equal to or more than the predetermined value, the hydraulic braking force is reduced and the regenerative braking force is increased according to the decrease. And a brake squeeze preventing means.