JP4715316B2 - Brake force control device for vehicle having torque converter in drive system - Google Patents

Description

  The present invention relates to a braking force control device for a vehicle having a torque converter in a drive system. More specifically, the friction material is pressed against a rotating member that rotates together with a wheel, and the braking force is controlled by controlling the pressing force. The present invention relates to a braking force control device that controls

In vehicles such as automobiles equipped with a torque converter in the drive system, when the vehicle is in a creeping driving state from a braking stop state, a groan commonly referred to as a goo sound in the process of gradually decreasing the braking force Sound is generated. As one of the braking force control devices for vehicles such as automobiles that reduce the generation of such a glow sound, for example, as described in Patent Document 1 below, when the occurrence of a grow sound is detected, the brake pressure is pulsated. However, there is already known a braking force control device configured to reduce pressure.
Japanese Patent Laid-Open No. 2000-21493

  However, in the conventional braking force control apparatus as described above, it is necessary to detect the vibration of the brake pad and determine the generation of the glow sound based on the vibration level of the brake pad, and the detection accuracy of the generation of the gross sound is poor. Further, there is a problem in that the generation of a growling sound cannot be reliably and effectively reduced, and a sensor for detecting the vibration of the brake pad is required, and the calculation load necessary for determining the generation of the growling sound is large.

  In recent years, there has been an increasing demand for brake performance from the standpoint of ensuring safety. However, when high-performance friction materials are used to improve the brake performance, it can be used in a wide range of brake pressures. When the brake pressure is reduced so that the generation of noise is reliably reduced, the discrepancy between the driver's braking operation amount and the actual braking force of the wheels increases. There is a problem that people feel uncomfortable.

  The present invention has been made in view of the above-described problems in the conventional braking force control apparatus configured to reduce the pressure while pulsating the brake pressure when the occurrence of a glow sound is detected. The main problem is that the Glone sound is generated only when the brake pressure gradually decreases and the vehicle moves from the braking stop state to the creep running state and the brake pressure is within a specific range, and the vehicle is substantially braked. In a state where the vehicle is running without being driven, that is, in a state where the wheel is rotating without being substantially braked, no glane sound is generated even if the brake pressure is increased to the specific range. By paying attention, it is possible to effectively reduce the occurrence of a growling sound while reducing the possibility of the driver feeling uncomfortable without requiring a sensor or a large amount of computation.

According to the present invention, the main problem described above is a vehicle braking force control device applied to a vehicle having a torque converter in a drive system according to the configuration of claim 1. Means for detecting, braking force generating means for generating a braking force by pressing a friction material against a rotating member provided on each wheel and rotating together with the wheel, and said braking force generating means based on at least a driver's braking operation amount In the vehicle braking force control device having a control means for controlling the braking force of each wheel by controlling the pressing force of the vehicle, the vehicle has a means for detecting a stop state and a running state of the vehicle, When the vehicle shifts from a braking stop state to a creep running state, the pressing force is instantaneously reduced so that the pressing force is lower than the pressing force in the glow sound generation region , and immediately thereafter. Reinstated It is achieved by the braking force control apparatus for a vehicle according to claim Rukoto.

According to the present invention, in order to effectively achieve the main problems described above, in the configuration of claim 1, the first and second reference values are set to the upper limit pressing force and the lower limit of the Glone sound generation region, respectively. As the pressing force, the control means instantaneously reduces the pressing force so that the pressing force becomes a value lower than the second reference value after the pressing force becomes equal to or less than the first reference value . Immediately thereafter, it is configured to return instantaneously (configuration of claim 2).

According to the present invention, in order to effectively achieve the above-described main problems, in the configuration according to claim 1 or 2, the control means instantaneously applies the pressing force at different timings for at least two wheels. It is comprised so that it may reduce | restor to immediately and it may return instantaneously immediately after that (structure of Claim 3).

According to the present invention, in order to effectively achieve the above-mentioned main problems, in the configuration of claim 1 or 2, the vehicle has left and right front wheels and left and right rear wheels, and the control means includes all The wheel is configured to instantaneously reduce the pressing force at timings different from each other , and to immediately return the wheel immediately thereafter (configuration of claim 4).

According to the present invention, in order to effectively achieve the main problems described above, in the configuration of claim 1 or 2, the vehicle has left and right front wheels and left and right rear wheels, and the control means has left and right front wheels. The pressing force is instantaneously reduced at the same timing with respect to each other and immediately returned immediately thereafter, and the pressing force is instantaneously applied to the left and right rear wheels at the same timing and different from the left and right front wheels. It is comprised so that it may reduce | restor to immediately and it may return instantaneously immediately after that (structure of Claim 5).

According to the present invention, in order to effectively achieve the main problems described above, in the configuration of claims 1 to 5, the control means controls the braking force of the rear wheel to be lower than that of the front wheel. In this case, the pressing force of the front wheel is momentarily reduced, and immediately after that, the pressing force of the rear wheel is instantaneously increased, and immediately after that, the pressing force is instantaneously restored. (Structure of claim 6).

According to the present invention, in order to effectively achieve the main problems described above, the means for detecting the amount of braking operation by the driver is a braking operator operated by the driver. The momentary increase / decrease of the pressing force is not transmitted to the braking operator (structure of claim 7).

According to the first aspect of the present invention, when the vehicle shifts from the braking stop state to the creep running state, the pressing force instantaneously decreases so that the pressing force becomes a value lower than the pressing force in the glow sound generation region. Since the pressing force is instantaneously and temporarily reduced by being instantaneously restored immediately after that, it is recovered after it has been instantaneously generated. Thus, no glone sound is generated after the instantaneous reduction and return of the pressing force is completed, thereby effectively reducing the generation of the grow sound.

In addition, since it is not necessary to detect the occurrence of a glane sound and the pressure force is reduced and restored instantaneously, a sensor for detecting the occurrence of a glane sound and a large amount of calculation are not required, and the amount of braking operation by the driver The possibility that the driver feels uncomfortable due to the deviation from the braking force of the vehicle can be reliably reduced.

Further, according to the configuration of the second aspect, the first and second reference values are set as the upper limit pressing force and the lower limit pressing force of the glow sound generation region, respectively, and the pressing force is reduced after the pressing force becomes equal to or lower than the first reference value. Since the pressing force is momentarily reduced so that the pressure becomes lower than the second reference value , and immediately after that , the pressing force is instantaneously restored, so that the pressing force is larger than the first reference value. Is instantaneously reduced , and immediately after that, it can be surely prevented that the generation of the glow sound cannot be effectively terminated.

According to the configuration of claim 3, the pressing force is instantaneously reduced at different timings for at least two wheels and immediately returned immediately thereafter. Therefore, the pressing force is at the same timing for at least two wheels. Compared to the case where the vehicle is instantaneously reduced and immediately restored immediately thereafter, the degree to which the braking force of the entire vehicle is reduced is reduced, thereby effectively reducing the possibility of the driver feeling uncomfortable. can do.

Further, according to the configuration of claim 4, the vehicle has left and right front wheels and left and right rear wheels, and the pressing force is instantaneously reduced at different timings for all the wheels and immediately returned immediately thereafter. Therefore, the degree to which the braking force of the entire vehicle decreases compared to the case where the pressing force is instantaneously reduced at the same timing for any two or more wheels and immediately after that is instantaneously restored. This reduces the risk that the driver will feel uncomfortable.

According to the fifth aspect of the present invention, the vehicle has the left and right front wheels and the left and right rear wheels, and the pressing force is instantaneously reduced at the same timing with respect to the left and right front wheels, and immediately returned immediately thereafter. At the same time, the pressing force is instantaneously reduced at a timing that is the same for the left and right rear wheels and different from that for the left and right front wheels, and is immediately restored immediately thereafter, so that all the wheels are pressed at the same timing. is reduced manner the pressure moment, as compared with the case induced to instantaneously return immediately thereafter, reducing the degree of braking force of the entire vehicle is lowered, reliably reduce possibility that the driver feels uncomfortable by this In addition, it is possible to reliably prevent an unnecessary yaw moment from acting on the vehicle due to the difference in braking force between the left and right wheels.

According to the sixth aspect of the present invention, in a situation where the braking force of the rear wheel is controlled to be lower than that of the front wheel, the pressing force of the front wheel is instantaneously reduced and immediately returned immediately thereafter. Because the pressing force of the rear wheel is momentarily increased and immediately restored immediately thereafter, the braking force of the entire vehicle is momentarily reduced, the driver feels uncomfortable, and the vehicle speed increases momentarily. Can be reduced reliably.

According to the seventh aspect of the invention, the means for detecting the amount of braking operation of the driver detects the amount of operation of the braking operator by the driver, and the momentary increase / decrease of the pressing force is not transmitted to the braking operator. Thus, it is possible to reliably prevent the driver from feeling uncomfortable as a sudden change in the operation amount of the braking operator due to the momentary increase / decrease in the pressing force being transmitted to the braking operator.

[Preferred embodiment of problem solving means]
According to one preferred aspect of the present invention, in the configuration of the above-described first to seventh aspects, the control means instantaneously reduces the pressing force and immediately returns immediately after that, at least by the driver. It is comprised so that it may return to the condition which controls pressing force based on the amount of braking operation (Preferred aspect 1).

According to another preferred embodiment of the present invention, in the configuration of the above-mentioned claims 1 to 7 or the preferred embodiment 1, the control means reduces the pressing force for a predetermined time, and immediately after that, instantaneously. The pressing force is instantaneously reduced by returning, and immediately returned immediately thereafter (preferred aspect 2).

  According to another preferred embodiment of the present invention, in the preferred embodiment 2, the predetermined time is configured to be a preset time (preferred embodiment 3).

  According to another preferred aspect of the present invention, in the configuration of the first to seventh aspects or the preferred aspects 1 to 3, the braking force generating means presses the friction member against the rotating member by the braking hydraulic pressure. Thus, the braking force is generated, and the control means is configured to control the pressing force by controlling the braking fluid pressure (preferred aspect 4).

  According to another preferred aspect of the present invention, the braking force generating means presses the friction material against the rotating member by electromagnetic force in the configuration of the above-mentioned claims 1 to 7 or the preferred aspects 1 to 3. The control means is configured to control the pressing force by controlling the electromagnetic force (preferred aspect 5).

According to another preferred embodiment of the present invention, in the configuration of the above-mentioned claims 3 to 5 or the preferred embodiments 1 to 5, the control means overlaps the time during which the pressing force is reduced between the wheels. It is configured to instantaneously reduce the pressing force at different timings by instantaneously reducing the pressing force so as not to immediately return it immediately thereafter, and to instantaneously return immediately after that (preferred embodiment) 6).

According to another preferred embodiment of the present invention, in the configuration of the above-mentioned claim 5 or the preferred embodiments 1 to 6, the control means reduces the pressing force at least partially between the wheels. The pressing force is instantaneously reduced so as to overlap each other , and immediately after that, the pressing force is instantaneously reduced at the same timing , and immediately after that, the pressing force is instantaneously restored. (Preferred embodiment 7)

According to another preferred embodiment of the present invention, in the configuration of the preferred embodiment 7, the control means simultaneously lowers the pressing force at the same time and immediately returns immediately thereafter, so that the same timing is obtained. The pressing force is instantaneously reduced at, and immediately after that, the pressure is instantaneously restored (preferred aspect 8).

  According to another preferred aspect of the present invention, in the configuration of the above-mentioned claim 6 or the preferred aspects 1 to 8, the control means pushes the rear wheel while instantaneously reducing the pushing force of the front wheel. Configured to increase pressure (Preferred Aspect 9).

According to another preferred embodiment of the present invention, in the configuration of the above-mentioned claim 7 or the preferred embodiments 1 to 9, the braking force generating means presses the friction material against the rotating member by the braking hydraulic pressure. The braking force is generated, and the control means controls the pressing force by controlling the brake fluid pressure, and the master cylinder, which increases or decreases the pressure when the driver operates the braking operator, communicates with the braking force generating means. By being cut off, the momentary increase / decrease of the pressing force is configured not to be transmitted to the braking operator (preferred aspect 10).

  The present invention will now be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram showing a hydraulic circuit of a first embodiment of a vehicle braking force control device according to the present invention configured as a hydraulic braking force control device, and a block diagram showing a control system. In FIG. 1, the solenoid of each valve is not shown for the sake of simplicity.

  In FIG. 1, reference numeral 10 denotes an electrically controlled hydraulic brake device. The brake device 10 includes a master cylinder 14 that pumps brake oil in response to a driver's depressing operation of the brake pedal 12. Have. A dry stroke simulator 16 is provided between the brake pedal 12 and the master cylinder 14.

  The master cylinder 14 has a first master cylinder chamber 14A and a second master cylinder chamber 14B, and these master cylinder chambers have a brake hydraulic pressure supply conduit 18 for the left front wheel and a brake hydraulic pressure control conduit for the right front wheel, respectively. One end of 20 is connected. Wheel cylinders 22FL and 22FR for controlling the braking force of the left front wheel and the right front wheel are connected to the other ends of the brake hydraulic pressure control conduits 18 and 20, respectively.

  In the middle of the brake hydraulic pressure supply pipes 18 and 20, there are provided normally open type electromagnetic on / off valves (so-called master cut valves) 24L and 24R that function as communication control valves, respectively. It functions as a shut-off valve that controls communication between the cylinder chamber 14A and the second master cylinder chamber 14B and the corresponding wheel cylinders 22FL and 22FR. A wet stroke simulator 28 is connected to the brake hydraulic pressure supply conduit 18 between the master cylinder 14 and the electromagnetic open / close valve 24FL via a normally closed electromagnetic open / close valve (normally closed valve) 26.

  A reservoir 30 is connected to the master cylinder 14, and one end of a hydraulic pressure supply conduit 32 is connected to the reservoir 30. An oil pump 36 driven by an electric motor 34 is provided in the middle of the hydraulic supply conduit 32, and an accumulator 38 that accumulates high-pressure hydraulic pressure is connected to the hydraulic supply conduit 32 on the discharge side of the oil pump 36. One end of a hydraulic discharge conduit 40 is connected to the hydraulic supply conduit 32 between the reservoir 30 and the oil pump 36. The reservoir 30, the oil pump 36, the accumulator 38, and the like function as a high pressure source for increasing the pressure in the wheel cylinders 22FL, 22FR, 22RL, and 22RR as will be described later.

  Although not shown in FIG. 1, a conduit is provided for connecting the suction-side hydraulic supply conduit 32 and the discharge-side hydraulic supply conduit 32 of the oil pump 36, and an accumulator 38 is provided in the middle of the conduit. A relief valve is provided that opens when the pressure exceeds a reference value and returns oil from the discharge-side hydraulic supply conduit 32 to the suction-side hydraulic supply conduit 32.

  The hydraulic pressure supply conduit 32 on the discharge side of the oil pump 36 is connected to the brake hydraulic pressure supply conduit 18 between the electromagnetic on-off valve 24L and the wheel cylinder 22FL by a hydraulic control conduit 42, and the electromagnetic on-off valve 24R and the wheel by a hydraulic control conduit 44. It is connected to a brake hydraulic pressure supply conduit 20 between the cylinder 22FR, a hydraulic control conduit 46 to a left rear wheel wheel cylinder 22RL, and a hydraulic control conduit 48 to a right rear wheel wheel cylinder 22RR. .

  Normally closed electromagnetic linear valves 50FL, 50FR, 50RL, and 50RR are provided in the middle of the hydraulic control conduits 42, 44, 46, and 48, respectively. The hydraulic control conduits 42, 44, 46, 48 on the side of the wheel cylinders 22FL, 22FR, 22RL, 22RR with respect to the linear valves 50FL, 50FR, 50RL, 50RR are connected to the hydraulic discharge conduit 40 by the hydraulic control conduits 52, 54, 56, 58, respectively. And normally closed electromagnetic linear valves 60FL and 60FR are provided in the middle of the hydraulic control conduits 52 and 54, respectively, and normally closed electromagnetic solenoids are provided in the middle of the hydraulic control conduits 56 and 58, respectively. There are provided normally-open electromagnetic linear valves 60RL and 60RR that are cheaper than the conventional linear valves.

  The linear valves 50FL, 50FR, 50RL, 50RR function as pressure-increasing valves (holding valves) for the wheel cylinders 22FL, 22FR, 22RL, 22RR, respectively. The linear valves 60FL, 60FR, 60RL, 60RR are wheel cylinders 22FL, 22FR, 22RL, respectively. The linear valves function as pressure reducing valves for 22RR, so that these linear valves form a pressure increasing / decreasing control valve for controlling supply / discharge of high pressure oil to / from each wheel cylinder from the accumulator 38 in cooperation with each other.

  When the electromagnetic on / off valve is abnormal and the braking force cannot be controlled normally, no drive current is supplied to each electromagnetic on / off valve, each linear valve and the motor 34, and the electromagnetic on / off valves 24L and 24R are in the open state. The electromagnetic on-off valve 26, the linear valves 50FL to 50RR, the linear valves 60FL and 60FR are maintained in a closed state, and the linear valves 60RL and 60RR are maintained in an open state (non-control mode), whereby left and right front wheels The pressure in the wheel cylinder is directly controlled by the master cylinder 14.

  As shown in FIG. 1, a brake hydraulic pressure control conduit 18 between the first master cylinder chamber 14A and the electromagnetic on-off valve 24L detects a pressure in the control conduit as a first master cylinder pressure Pm1. One pressure sensor 66 is provided. Similarly, the brake pressure control conduit 20 between the second master cylinder chamber 14B and the electromagnetic on-off valve 24R is provided with a second pressure sensor 68 for detecting the pressure in the control conduit as the second master cylinder pressure Pm2. It has been. The brake pedal 12 is provided with a stroke sensor 70 for detecting a brake pedal depression stroke St by a driver, and a pressure for detecting the pressure in the conduit as an accumulator pressure Pa is provided in a hydraulic supply conduit 32 on the discharge side of the oil pump 34. A sensor 72 is provided.

  Pressure sensors for detecting the pressure in the corresponding conduits as the pressures Pfl and Pfr in the wheel cylinders 22FL and 22FR are provided in the brake hydraulic pressure supply conduits 18 and 20 between the electromagnetic on-off valves 24L and 24R and the wheel cylinders 22FL and 22FR, respectively. 74FL and 74FR are provided. Further, in the hydraulic control conduits 46 and 48 between the electromagnetic on-off valves 50RL and 50RR and the wheel cylinders 22RL and 22RR, respectively, pressure sensors for detecting the pressure in the corresponding conduits as the pressures Prl and Prr in the wheel cylinders 22RL and 22RR. 74RL and 74RR are provided.

  The electromagnetic open / close valves 24L and 24R, the electromagnetic open / close valve 26, the electric motor 34, the linear valves 50FL to 50RR, and the linear valves 60FL to 60RR are controlled by an electronic control unit 78. The electronic control unit 78 includes a microcomputer 80 and a drive circuit 82. Although not shown in detail in FIG. 1, the microcomputer 80 has, for example, a CPU, a ROM, a RAM, and an input / output port device, which are connected to each other via a bidirectional common bus. It may be.

  In the microcomputer 80, a signal indicating the first master cylinder pressure Pm1 and the second master cylinder pressure Pm2 from the pressure sensors 66 and 68, a signal indicating the depression stroke St of the brake pedal 12 from the stroke sensor 70, and a pressure sensor 72, respectively. A signal indicating the accumulator pressure Pa, a signal indicating the pressure Pi (i = fl, fr, rl, rr) in the wheel cylinders 22FL to 22RR, and a signal indicating the vehicle speed V from the vehicle speed sensor 76 are input from the pressure sensors 74FL to 74RR, respectively. Is done.

  The microcomputer 80 stores a braking force control routine according to the flowchart shown in FIG. 2 as will be described later, and maintains the electromagnetic on-off valve 26 in the open state and closes the electromagnetic on-off valves 24L and 24R when normal. The vehicle target deceleration Gt is calculated based on the master cylinder pressures Pm1 and Pm2 detected by the pressure sensors 66 and 68 and the depression stroke St detected by the stroke sensor 70, and the vehicle target deceleration Gt is obtained. Based on this, the target wheel cylinder pressure Pti (i = fl, fr, rl, rr) of each wheel is calculated to be higher than the master cylinder pressures Pm1, Pm2, so that the braking pressure Pi of each wheel becomes the target wheel cylinder pressure Pti. Each linear valve 50FL-50RR and 60FL-60RR are controlled.

  As will be understood from the above description, the microcomputer 80 calculates the target wheel cylinder pressure of each wheel to a value higher than the master cylinder pressures Pm1 and Pm2 based on the braking operation amount of the driver, and the electromagnetic opening / closing valves 24L and 24R, The valve 26L, the motor 34, the linear valves 50FL to 50RR, the linear valves 60FL to 60RR, the electronic control device 78, the pressure sensor 66, etc. The linear valves 50FL to 50RR and the linear valves 60FL to 60RR are controlled so that the wheel cylinder pressure of each wheel becomes the corresponding target wheel cylinder pressure with the valve 24R closed.

  In this case, the oil pump 36, the linear valves 50FL to 50RR, the linear valves 60FL to 60RR, etc. of the brake device 10 function as braking pressure control means for controlling the braking pressure of each wheel, that is, the pressure PI in the wheel cylinders 22FL to 22RR. Further, as shown in FIG. 1, the wheel cylinders 22FL to 22RR are provided on each wheel by increasing or decreasing the pressure Pi therein, so that rotating members 86FL to 86RR such as a rotor disk and a brake drum that rotate together with the wheels. On the other hand, it constitutes a part of the braking force generators 90FL to 90RR that press the friction materials 88FL to 88RR such as brake shoes to generate and increase or decrease the braking force.

  Although not shown in FIG. 1, the driving force of the engine is transmitted to the propeller shaft via an automatic transmission including a torque converter and a transmission, and the driving force of the propeller shaft is transmitted to the left and right driving wheels via a differential or the like. Communicated. The driving wheels may be left and right front wheels or left and right rear wheels, or may be four wheels, left and right front wheels and left and right rear wheels.

In the illustrated embodiment 1, the microcomputer 80 shifts from the braking stop state to the creep running state in the braking state, and instantaneously reduces the braking pressure of each wheel in order to prevent the generation of a glone sound . When it is determined immediately after that whether or not it is necessary to instantaneously reduce the braking pressure of each wheel, and when it is determined that it is necessary to instantaneously return immediately thereafter , the linear valve 50FL˜ By instantaneously opening the linear valves 60FL to 60RR with the valve 50RR closed, the braking pressure Pi of each wheel is suddenly reduced to a pressure lower than the lower limit braking pressure Pg2 in the glow sound generation region, Thereafter, the brake pressure Pi of each wheel is suddenly increased to return to a state in which control is performed so as to reach the target wheel cylinder pressure Pti.

  Next, the braking force control in the embodiment will be described with reference to the flowchart shown in FIG. Note that the control according to the flowchart shown in FIG. 2 is started when the microcomputer 80 is activated, and is repeatedly executed at predetermined time intervals.

  Prior to the control according to the flowchart shown in FIG. 2, the electromagnetic on-off valve 26 is closed and the electromagnetic on-off valves 24L and 24R are opened, thereby disconnecting the communication between the master cylinder 14 and the wet stroke simulator 28. At the same time, the master cylinder 14 and the wheel cylinders 22FL, 22FR, 22RL, and 22RR of each wheel are connected in communication. In step 40, the electromagnetic on-off valve 26 is opened or maintained in the open state. The electromagnetic open / close valves 24L and 24R are closed or maintained in a closed state, whereby the master cylinder 14 and the wet stroke simulator 28 are connected in communication, and the master cylinder 14 and the wheel cylinders 22FL, 22FR, 22RL of each wheel are connected. , 22RR is disconnected.

  First, in step 10, a signal indicating the master cylinder pressure Pm1 detected by the pressure sensor 66 is read, and in step 20, the average value Pma of the master cylinder pressures Pm1 and Pm2 is shown in FIG. The target deceleration Gpt based on the master cylinder pressure is calculated from the map corresponding to the graph.

  In step 30, the target deceleration Gst based on the depression stroke is calculated from the map corresponding to the graph shown in FIG. 5 based on the depression stroke St detected by the stroke sensor 70.

  In step 40, the weight α (0 ≦ α ≦ 1) for the target deceleration Gpt is calculated from the map corresponding to the graph shown in FIG. 6 based on the previous final target deceleration Gtf. In the illustrated embodiment, the weight α is calculated based on the previous final target deceleration Gtf, but may be modified to be calculated based on the target deceleration Gpt or Gst.

In step 50, the final target deceleration Gt is calculated as a weighted sum of the target deceleration Gpt and the target deceleration Gst according to the following equation 1.
Gt = α · Gpt + (1−α) Gst (1)

In step 60, Ki (i = fl, fr, rl, rr) is defined as a coefficient of the target wheel cylinder pressure of each wheel with respect to the final target deceleration Gt (a positive coefficient considering the braking effectiveness coefficient of each wheel). The target wheel cylinder pressure Pti (i = fl, fr, rl, rr) of each wheel is calculated according to the following formula 2.
Pti = Ki ・ Gt (2)

  In step 70, it is determined whether or not the braking pressure reduction control is being performed to prevent the generation of a growling sound. If an affirmative determination is made, the process proceeds to step 110. If a negative determination is made, the process proceeds to step 110. Proceed to 80.

  In step 80, it is determined whether or not the vehicle is in a creeping state in a braking state. If a negative determination is made, the process proceeds to step 100. If an affirmative determination is made, the process proceeds to step 90.

  In step 90, it is determined whether or not the start condition of the braking pressure reduction control for preventing the generation of a glow sound is satisfied. If an affirmative determination is made, the process proceeds to step 120, and a negative determination is made. If so, go to Step 100. In this case, whether or not the start condition of the braking pressure reduction control is satisfied is determined by, for example, a preset time To (positive constant) from the time when the vehicle shifts from the braking stop state to the creep running state in the braking state. ) May have been determined.

  In step 100, the wheel cylinder pressure Pi of each wheel is controlled by hydraulic feedback so as to become the corresponding target wheel cylinder pressure Pti, whereby the braking force of each wheel is controlled according to the amount of braking operation by the driver. .

  In step 110, it is determined whether or not the braking pressure reduction control for preventing the generation of a glow sound has been completed. If an affirmative determination is made, the process proceeds to step 100. If a negative determination is made, the process proceeds to step 100. Proceed to 120.

In step 120, the pressure reducing linear valves 60FL-60RR are closed while the holding linear valves 50FL-50RR are closed for a predetermined reduction time Td (positive constant) set in advance for all the wheels. By opening the valve, the wheel cylinder pressure Pi of each wheel is suddenly lowered to a pressure lower than the lower limit value P2 of the glow sound generation region, and then the wheel cylinder pressure Pi of each wheel is suddenly increased. Immediately before the cylinder pressure Pi becomes the corresponding target wheel cylinder pressure Pti, the wheel cylinder pressure Pi is returned to the state controlled by the hydraulic feedback so as to become the corresponding target wheel cylinder pressure Pti. Is instantaneously reduced , and immediately after that , it is instantaneously restored.

  Thus, according to the first embodiment shown in the drawing, in steps 20 to 60, the target braking pressure Pti of each wheel is calculated according to the depression stroke St of the brake pedal 12 and the average value Pma of the master cylinder pressures Pm1 and Pm2, and the step At 100, the braking pressure Pi of each wheel is controlled to become the target braking pressure Pti, so that the control is performed in accordance with the braking operation amount of the driver.

Then, in steps 70 to 90, it is determined whether or not it is necessary to instantaneously reduce the braking pressure of each wheel in order to prevent the generation of a glone sound , and immediately after that, it is necessary to return instantaneously. When it is determined that the braking pressure needs to be reduced instantaneously and immediately after that , in step 120, the braking pressure Pi of each wheel is lower than the lower limit braking pressure Pg2 in the area where the sound is generated. After the pressure is instantaneously reduced to the pressure, the brake pressure Pi of each wheel is instantaneously returned to the state where the control is performed so as to become the target wheel cylinder pressure Pti.

Therefore, according to the first embodiment shown in the figure, the amount of braking operation by the driver is gradually reduced, so that the vehicle shifts from the braking stop state to the creep running state in the braking state, and the braking pressure of each wheel is reduced in the glone sound generation region. Even if the value is reached, the braking pressure of each wheel is instantaneously reduced to a pressure lower than the lower limit braking pressure in the area where the sound is generated , and immediately after that , it can be instantaneously restored. As compared with the case where the braking pressure of each wheel is lowered and restored over a relatively long time, the vehicle speed increases unnaturally due to the reduction and restoration of the braking pressure. It is possible to effectively reduce the possibility that the driver will feel uncomfortable due to the phenomenon.

  For example, FIG. 6 and FIG. 7 respectively show a vehicle equipped with a conventional general braking force control device and a braking force control device according to the first embodiment. It is a graph which shows the example of the change situation of braking pressure Pi and vehicle speed V, and the generation situation of a Glone sound in the case of changing from the stop state to the creep running state in the braking state.

  As shown in FIGS. 6 and 7, the braking pressure starts to decrease at time t1, the vehicle starts creeping at time t2, and braking pressure Pi starts at time t3. Is the upper limit value Pg1 of the grow sound generation area. As shown in FIG. 6, in the case of a conventional general braking force control device, a glow sound begins to be generated at time t3, and the brake pressure Pi is the lower limit brake pressure in the glow sound generation region. Continue until time t6 when the pressure drops below Pg2.

  On the other hand, according to the first embodiment shown in the figure, as shown in FIG. 7, the sudden decrease in the braking pressure is started at the time t4 when the predetermined time To has elapsed from the time t2, and the braking pressure Pi is increased. At time t5 when it becomes lower than the lower limit value Pg2 of the grow sound generation area, the grow sound stops, and no grow sound is generated even if the braking pressure Pi rises above the lower limit value Pg2.

  Further, according to the first embodiment shown in the figure, the instantaneous decrease in the braking pressure of each wheel occurs when a preset time To elapses from the time when the vehicle shifts from the braking stop state to the creep running state in the braking state. Therefore, in the situation where the braking pressure Pi of each wheel is higher than the upper limit braking pressure Pg1 in the area where the sound is generated, the braking pressure of each wheel is reduced unnecessarily, and the generation of the sound of the grow is effectively performed. It is possible to reduce the possibility of being unable to prevent.

  FIG. 8 is a flowchart showing a braking pressure lowering control routine of braking force control in the second embodiment of the vehicle braking force control device according to the present invention configured as a hydraulic braking force control device, and FIG. 4 is a graph showing an example of a change in braking pressure of each wheel when a vehicle shifts from a braking stop state to a creep running state in a braking state by gradually reducing the amount of braking operation performed by the driver.

In this second embodiment, although not shown in the figure, steps 10 to 110 are executed in the same manner as in the first embodiment described above. In step 120, each step is performed according to the routine shown in FIG. The braking pressure of the wheel is instantaneously reduced , and immediately after that , it is instantaneously restored.

As shown in FIG. 8, in step 130, it is determined whether or not the instantaneous lowering control of the braking pressure Pfl of the left front wheel is completed. If an affirmative determination is made, the process proceeds to step 150. When the negative determination is made, in step 140, the instantaneous lowering control of the braking pressure Pfl of the left front wheel is executed in the same manner as in the first embodiment, and the wheels other than the left front wheel are controlled. The brake pressure is controlled so as to become the corresponding target wheel cylinder pressure Pti, and then the process returns to step 10.

In step 150, it is determined whether or not the instantaneous lowering control of the braking pressure Pfr of the right front wheel has been completed. If an affirmative determination is made, the process proceeds to step 170. If a negative determination is made, the process proceeds to step 170. In 160, the instantaneous lowering control of the braking pressure Pfr of the right front wheel is executed in the same manner as in the case of the left front wheel, and the braking pressures of the wheels other than the right front wheel are respectively set to the corresponding target wheel cylinder pressures Pti. Then, control returns to step 10.

In step 170, it is determined whether or not the instantaneous lowering control of the braking pressure Prl of the left rear wheel has been completed. If an affirmative determination is made, the process proceeds to step 190, and if a negative determination is made. In step 180, the instantaneous lowering control of the braking pressure Prl of the left rear wheel is executed in the same manner as in the case of the left front wheel, and the braking pressures of the wheels other than the left rear wheel correspond to the respective target wheel cylinders. The pressure Pti is controlled so as to return to step 10.

In step 190, it is determined whether or not the instantaneous lowering control of the braking pressure Prr for the right rear wheel is completed. If the determination is negative, the braking pressure Prr for the right rear wheel is determined in step 200. with momentary reduction control is executed in the same manner as the case of the left front wheel, the braking pressure of the wheel other than the right rear wheel is controlled so as to be corresponding target wheel cylinder pressure Pti, the positive determination rows When it is determined, it is determined in step 210 that the instantaneous reduction control of the braking pressure of each wheel has been completed, and when step 200 or 210 is completed, the process returns to step 10.

Thus, according to the second embodiment shown in the figure, the braking pressure Pi of all the wheels is instantaneously reduced at the same time, and is not immediately restored immediately thereafter, but as shown in FIG. Since the braking pressure is decreased instantaneously and immediately after that , it can be instantaneously restored, so that it is possible to reliably prevent the occurrence of a gloomy sound after the instantaneous decrease and restoration of the braking pressure as in the case of the first embodiment. In addition to the above, the amount of decrease in the braking force of the entire vehicle is reduced as compared with the case of the above-described first embodiment, thereby causing the driver to feel uncomfortable due to a phenomenon such as an unnatural increase in vehicle speed. Can be further effectively reduced.

  Particularly, according to the second embodiment shown in the figure, the braking pressure Pi of each wheel is decreased without overlapping in time, so that the braking pressure of each wheel is decreased in overlapping with time. Thus, the possibility that the driver feels uncomfortable due to a phenomenon such as an unnatural increase in the vehicle speed can be reliably reduced.

In the illustrated embodiment 2, the instantaneous decrease and return of the braking pressure are executed in the order of the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel. The lowering and returning are not limited in this order, and may be executed in the order of the left front wheel, the right front wheel, the right rear wheel, and the left rear wheel, for example.

  FIG. 10 is a flowchart showing a braking pressure reduction control routine for braking force control in the third embodiment of the vehicle braking force control device according to the present invention configured as a hydraulic braking force control device. FIG. 4 is a graph showing an example of a change in braking pressure of each wheel when a vehicle shifts from a braking stop state to a creep running state in a braking state by gradually reducing the amount of braking operation performed by the driver.

Also in the third embodiment, although not shown in the figure, steps 10 to 110 are executed in the same manner as in the first embodiment, and in step 120, each step is performed according to the routine shown in FIG. The braking pressure of the wheel is instantaneously reduced , and immediately after that , it is instantaneously restored.

As shown in FIG. 10, in step 230, it is determined whether or not the instantaneous lowering control of the braking pressures Pfl and Pfr of the left and right front wheels has been completed. If an affirmative determination is made, step 250 is performed. When a negative determination is made, in step 240, the instantaneous lowering control of the braking pressures Pfl, Pfr of the left and right front wheels is executed in the same manner as in the first embodiment, and the left and right front wheels are controlled. braking pressure Prl of the left and right rear wheels to a degree that the left and right rear wheels will not lock when the brake pressure is reduced instantaneously, Prr is instantaneously increased, the flow returns to thereafter step 10. In this case, the instantaneous increase amounts of the braking pressures Prl and Prr of the left and right rear wheels are smaller than the magnitude of the instantaneous decrease amounts of the braking pressures Pfl and Pfr of the left and right front wheels.

In step 250, it is determined whether or not the instantaneous reduction control of the braking pressures Prl and Prr for the left and right rear wheels has been completed. If a negative determination is made, in step 260, the braking of the left and right rear wheels is determined. The instantaneous reduction control of the pressures Prl and Prr is executed in the same manner as in the case of the left and right front wheels, and the braking pressures Pfl and Pfr of the left and right front wheels are controlled to become the corresponding target wheel cylinder pressures Pti, respectively. When the determination is made, it is determined in step 270 that the instantaneous reduction control of the braking pressure of each wheel has been completed, and when step 260 or 270 is completed, the process returns to step 10.

Thus, according to the third embodiment shown in the figure, the braking pressure Pi of all the wheels is instantaneously reduced at the same time and is not instantaneously restored immediately thereafter, but as shown in FIG. Since the braking pressures of the left and right rear wheels are successively reduced instantaneously and immediately after that , they are instantaneously restored. As in the case of the first and second embodiments described above, a groan sound is generated after instantaneous reduction and restoration of the braking pressure. This can be prevented not only reliably, but also by reducing the amount of decrease in the braking force of the entire vehicle as compared with the case of the first embodiment described above, thereby causing the vehicle speed to increase unnaturally. Thus, the possibility of the driver feeling uncomfortable can be further effectively reduced.

Further, according to the third embodiment shown in the drawing, the braking pressures of the left and right wheels are instantaneously reduced at the same time and immediately restored immediately thereafter, so that the left and right wheels resulting from the instantaneous reduction and restoration of the braking pressure are obtained. Therefore, there is no difference between the braking force and the yaw moment resulting from this. Therefore, the braking pressure of the left and right wheels is instantaneously decreased sequentially and immediately after that. Therefore, the possibility of deterioration in vehicle behavior due to a significant decrease and return can be reliably reduced.

In particular, according to the illustrated third embodiment, the braking pressure Prl of the left and right rear wheels when the braking pressure of the right and left front wheels are instantaneously reduced, since Prr is raised momentarily, braking pressure of the right and left front wheels are instantaneously braking pressure Prl of the left and right rear wheels when it is lowered to, as compared with the case where Prr are controlled so as to be corresponding target wheel cylinder pressure Pti, to reduce the amount of reduction in the braking force of the entire vehicle, thereby The driver feels uncomfortable due to phenomena such as an unnatural increase in vehicle speed, and this effect can be effectively reduced. This is especially true for low-controlled vehicles.

Note the In Example 3 shown, the brake pressure Prl of the left and right rear wheels when the braking pressure of the right and left front wheels are momentarily reduced, but Prr is adapted to be instantaneously increased, the left and right front wheels braking pressure Prl of the left and right rear wheels when the brake pressure is reduced momentarily in, Prr may be modified to be controlled to the corresponding target wheel cylinder pressure Pti without being instantaneously increased.

  Further, the control for instantaneously increasing the braking pressure of the rear wheel when the braking pressure of the front wheel is instantaneously reduced may be performed in the above-described second embodiment or the fourth embodiment described later.

In the illustrated embodiment 3, the instantaneous braking pressure reduction control is executed in the order of the left and right front wheels and the left and right rear wheels, but the instantaneous braking pressure reduction control is limited to this order. For example, it may be executed in the order of the left front wheel and the right rear wheel, the right front wheel and the left rear wheel, the right front wheel and the left rear wheel, the left front wheel and the right rear wheel. Also in the case where momentary reduction control of the brake pressure is performed in that order, the braking pressure of the rear wheels of front wheels and left and right the same side where the brake pressure is reduced momentarily is instantaneously increased It is preferable.

  FIG. 12 is a flowchart showing a braking pressure reduction control routine of braking force control in the embodiment 4 of the vehicle braking force control apparatus according to the present invention configured as a modification of the embodiment 2. In FIG. 12, the same steps as those shown in FIG. 8 are assigned the same step numbers as those shown in FIG.

In the fourth embodiment, although not shown in the figure, each wheel is provided with a sound wave sensor for detecting a grow sound, and the presence or absence of the grow sound and the braking pressure are detected for each wheel by the sound wave sensor. It is possible to confirm the effect of preventing the generation of a glone sound by instantaneous drop control . However, the sonic sensor does not detect the generation of a glow sound in order to determine whether or not the instantaneous reduction control of the braking pressure should be started.

  In the fourth embodiment, steps 10 to 110 are executed in the same manner as in the first embodiment, and the braking pressure reduction control in step 120 is executed according to the routine shown in FIG. As shown in FIG. 12, the steps other than steps 135, 155, 175, and 195 are executed in the same manner as in the second embodiment.

If an affirmative determination is made in steps 130, 150, 170, 190, the determination of the effect of preventing the generation of a glone sound based on the detection results of the sound wave sensors in steps 135, 155, 175, 195, that is, the corresponding wheels, respectively. In this case, it is determined whether or not the generation of the glow sound has been stopped by the instantaneous reduction control of the braking pressure after the generation of the glow sound.

  When Steps 135, 155, 175, and 195 are completed, the process proceeds to Steps 150, 170, 190, and 210, respectively. When Step 210 is completed, a time set in advance for the next braking pressure reduction control in Step 220. Optimization of To and a predetermined reduction time Td is performed. That is, the time To and Td are corrected to a small value when the effect of preventing the generation of a growling sound is confirmed and when the sound of the growling sound is not generated, and the times To and Td are large when the effect of preventing the generation of the growling sound is not recognized. Corrected to value. In this case, if the effect of preventing the generation of a glone sound is recognized even when the times To and Td become the predetermined minimum values, the next braking pressure reduction control for the wheel may be omitted.

Thus, according to the fourth embodiment shown in the figure, it is possible not only to surely prevent the generation of a groan sound after the instantaneous reduction control of the braking pressure, as in the second embodiment, but also to set a preset time. It is possible to optimize the To and the predetermined reduction time Td to more reliably prevent the generation of a glone sound, and to reduce the braking pressure and unnecessary braking pressure for an unnecessarily long time. Can be prevented.

  Note that the determination of the effect of preventing the generation of a glone sound and the optimization of the times To and Td as in the fourth embodiment may be applied to the first or third embodiment.

As can be understood from the above description, according to each of the illustrated embodiments, a sensor for detecting the generation of a growl noise and a large amount of calculation are not required to determine whether or not the instantaneous reduction control of the braking pressure should be started. In addition, it is possible to effectively prevent the generation of a groan noise at a low cost. In particular, during normal braking, the communication between the master cylinder 14 and the wheel cylinders 22FL to 22RR of each wheel is a normally open type as a master cut valve. Since it is shut off by the electromagnetic on-off valves 24L and 24R, the driver does not feel a sense of incongruity due to the shock transmitted to the brake pedal 12 due to the instantaneous reduction control of the braking pressure.

  Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.

  For example, in each of the above-described embodiments, the braking pressure for preventing the generation of a glow sound when a preset time To elapses from the time when the vehicle shifts from the braking stop state to the creep running state in the braking state. It is determined that the start condition of the lowering control is satisfied, and the lowering control of the braking pressure is executed. However, after the vehicle shifts from the braking stop state to the creep running state in the braking state, the braking pressure Pi is When the pressure becomes lower than the upper limit braking pressure Pg1 in the sound generation region or when the average value Pma of the master cylinder pressures Pm1 and Pm2 becomes lower than the reference value Pmg1 corresponding to the upper limit braking pressure Pg1, It may be modified so that the decrease control is executed.

  In the first to third embodiments described above, the preset time To and the predetermined reduction time Td are constant, but these times may be variably set. For example, the time To may be the braking of the driver. The time Td is variably set according to the braking pressure decrease gradient due to the reduction of the braking operation amount of the driver so that the smaller the braking pressure decrease gradient due to the operation amount decrease, the time Td is the braking pressure at the start of control or the master cylinder pressure. It may be modified to be variably set according to the braking pressure at the start of control or the master cylinder pressure so as to decrease as the value decreases.

In each of the above-described embodiments, the time Td is the same for all the wheels. However, particularly when the braking pressure reduction control is sequentially performed, the braking pressure at the start of the braking pressure reduction control becomes later. Since the braking pressure becomes lower and lower than the lower limit braking pressure Pg2 in the Glone sound generation region due to a short time drop, the time Td may be corrected to become shorter later.

  In each of the above-described embodiments, the instantaneous decrease in the braking pressure is performed over time Td. However, the braking pressure is lower than the lower limit braking pressure Pg2 in the glow sound generation region. It may be modified so that the braking pressure starts to increase when it is confirmed that the brake pressure has been confirmed.

  In each of the above-described embodiments, the pressure is detected by the two pressure sensors 66 and 68. However, the master cylinder pressure may be corrected so as to be detected by one pressure sensor.

  In each of the above-described embodiments, the target braking pressure Pti of each wheel is based on the average value Pma of the master cylinder pressures Pm1 and Pm2 as a value indicating the braking operation amount of the driver and the depression amount St of the brake pedal. Although the driver's required deceleration Gt is calculated, the control of the braking force itself does not form the gist of the present invention, and is executed in any manner known in the art. Good.

  In each of the above-described embodiments, the pressure increase / reduction control valve for controlling the wheel cylinder pressure Pi of each wheel is composed of linear valves 50FL-50RR as pressure increase control valves and linear valves 60FL-60RR as pressure reduction control valves. However, these valves may be replaced with control valves having functions of increasing and decreasing pressure and holding.

  In each of the above-described embodiments, the communication between the master cylinder 14 and the wheel cylinders 22FL to 22RR of each wheel is normally shut off by the normally open electromagnetic on-off valves 24L and 24R serving as master cut valves. However, the braking force control device of the present invention is applied to a vehicle having a braking device that does not have a master cut valve and that increases or decreases the pressure in the wheel cylinders 22FL to 22RR of each wheel by the pressure of the master cylinder 14. The braking device may be a braking device in which the pressing force is generated electromagnetically as long as the braking force is generated by pressing the friction material against the rotating member that rotates together with the wheel.

FIG. 1 is a schematic configuration diagram showing a hydraulic circuit of an embodiment of a vehicle braking force control device according to the present invention configured as a hydraulic braking force control device, and a block diagram showing a control system. 3 is a flowchart showing a braking force control routine in the first embodiment. It is a graph which shows the relationship between the average value Pma of a master cylinder pressure, and target deceleration Gpt. It is a graph which shows the relationship between the depression stroke St of a brake pedal, and the target deceleration Gst. It is a graph which shows the relationship between the weight (alpha) with respect to the last final target deceleration Gtf and the target deceleration Gpt. In a vehicle equipped with a conventional general braking force control device, when the amount of braking operation by the driver is gradually reduced, the vehicle shifts from a braking stop state to a creep running state in a braking state. It is a graph which shows the example of the change situation of braking pressure and vehicle speed V, and the generation situation of a Glone sound. In a vehicle equipped with the braking force control apparatus of the first embodiment, braking is performed when the vehicle shifts from a braking stop state to a creep running state in a braking state by gradually reducing the amount of braking operation performed by the driver. It is a graph which shows the example of the change of a pressure and the vehicle speed V, and the generation | occurrence | production situation of a growl sound. 7 is a flowchart showing a braking pressure reduction control routine of braking force control in a second embodiment of the vehicle braking force control device according to the present invention configured as a hydraulic braking force control device. The graph which shows the example of the change of the braking pressure of each wheel in Example 2 when a driver | operator's braking operation amount reduces gradually and a vehicle transfers to the creep driving state in a braking state from a braking stop state. It is. 10 is a flowchart showing a braking pressure reduction control routine of braking force control in Embodiment 3 of the vehicle braking force control device according to the present invention configured as a hydraulic braking force control device. The graph which shows the example of the change of the braking pressure of each wheel in Example 3 when a driver | operator's braking operation amount reduces gradually and a vehicle transfers to the creep driving state in a braking state from a braking stop state. It is. 10 is a flowchart showing a braking pressure reduction control routine of braking force control in Embodiment 4 of a vehicle braking force control apparatus according to the present invention configured as a modified example of Embodiment 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Brake apparatus 12 Brake pedal 14 Master cylinder 22FL-22RR Wheel cylinder 24F, 24R, 26 Electromagnetic on-off valve 50FL-50RR Linear valve 60FL-60RR Linear valve 66, 68 Pressure sensor 70 Stroke sensor 72, 74FL-74RR Pressure sensor 76 Vehicle speed sensor 78 Electronic control unit

Claims (7)

A braking force control device for a vehicle applied to a vehicle having a torque converter in a drive system, the means for detecting a braking operation amount of a driver, and a friction material for a rotating member provided on each wheel and rotating together with the wheel Braking force generating means for generating a braking force by pressing and control means for controlling the braking force of each wheel by controlling the pressing force of the braking force generating means based at least on the amount of braking operation of the driver. The vehicle braking force control device has a means for detecting a stop state and a running state of the vehicle, and the control means is configured such that when the vehicle shifts from a braking stop state to a creep running state, the pressing force is A braking force control apparatus for a vehicle, characterized in that the pressing force is instantaneously reduced so as to be a value lower than the pressing force in the glow sound generation region , and then immediately returned immediately thereafter . The first and second reference values are respectively set as an upper limit pressing force and a lower limit pressing force of the glow sound generation area, and the control means reduces the pressing force to the second reference value after the pressing force becomes equal to or less than the first reference value. 2. The vehicle braking force control device according to claim 1, wherein the pressing force is instantaneously reduced so as to be lower than a reference value of the first and immediately returned immediately thereafter . 3. The vehicle braking force control device according to claim 1, wherein the control unit instantaneously reduces the pressing force at timings different from each other for at least two wheels , and immediately returns the pressing force immediately thereafter . The vehicle has left and right front wheels and left and right rear wheels, and the control means instantaneously reduces the pressing force at different timings for all the wheels and immediately returns immediately thereafter. The vehicle braking force control apparatus according to 1 or 2. The vehicle has left and right front wheels and left and right rear wheels, and the control means instantaneously lowers the pressing force at the same timing with respect to the left and right front wheels and instantaneously returns immediately after that. The vehicle braking force control device according to claim 1 or 2, wherein the pressing force is instantaneously reduced at a timing different from that of the left and right front wheels and instantaneously returned immediately thereafter . In a situation where the control means controls the braking force of the rear wheel to be lower than that of the front wheel, the pressing force of the rear wheel is reduced when the pressing force of the front wheel is instantaneously reduced and immediately after that. The vehicle braking force control device according to claim 1, wherein the vehicle braking force is increased instantaneously and immediately after that .   The means for detecting the amount of braking operation of the driver detects the amount of operation of the braking operator by the driver, and an instantaneous increase or decrease in the pressing force is not transmitted to the braking operator. A braking force control device for a vehicle as described in 1.

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