JP5760489B2 - Vehicle brake system - Google Patents

Description

  The present invention relates to a vehicle brake system in which a friction brake and a regenerative brake are used together and the two brakes are operated independently of each other without coordination.

  As a means for braking a vehicle such as an automobile, a friction brake using friction resistance such as a disc brake or a drum brake and a generator (for example, a motor generator which is a driving source of a hybrid vehicle or an electric vehicle) A regenerative brake using a rotational resistance generated during power generation is known.

  Further, Patent Document 1 discloses a brake system (hereinafter referred to as “cooperative brake system”) that uses both a friction brake and a regenerative brake and operates these brakes in cooperation with each other.

  In this coordinated brake system, when the remaining capacity of the battery is small and a large amount of regenerative power can be received by the battery, it is possible to effectively use energy by increasing the ratio of the braking force by the regenerative brake. When the capacity is large and the regenerative power that can be received by the battery is small, the braking force by the regenerative brake is reduced, and the ratio of the braking force by the friction brake is increased instead. Power can be obtained. That is, according to the coordinated brake system, the required braking force can always be obtained while effectively using the regenerative energy according to the remaining capacity of the battery, so that the driver does not feel uncomfortable when operating the brake.

  However, in the coordinated brake system, it is necessary to control the ratio of each braking force by the friction brake and the regenerative brake so as to correspond to every driving state, which leads to complicated control and various sensors used for this control. Is required, which increases the production cost.

  On the other hand, a brake system (hereinafter referred to as “non-cooperative brake system”) that operates the friction brake and the regenerative brake individually without cooperation may be employed. This non-coordinated brake system distributes the braking force according to the driver's braking request to the friction brake and the regenerative brake in a predetermined distribution. According to this, the control of the regenerative brake can be simplified. In addition, the production cost can be reduced because fewer sensors are used for this control.

JP 2006-224768 A

  However, in the non-coordinated brake system, when the braking by the regenerative brake is restricted or prohibited due to the increase in the remaining capacity of the battery, etc., the braking force of the friction brake to compensate for this is provided in order to protect the battery. Since the increase control is not performed, the total braking force is reduced. In this case, the driver may feel uncomfortable that the braking force is small, contrary to expectations.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a brake system for a vehicle in which a driver does not always feel uncomfortable at the time of brake operation while effectively using energy by using a regenerative brake in a non-cooperative brake system. .

  In order to solve the above problems, a vehicle brake system according to the present invention is configured as follows.

First, the invention according to claim 1 of the present application is
A brake system for a vehicle that operates the friction brake means and the regenerative brake means in a non-cooperative manner in accordance with a stroke change of the brake operation means,
Brake operation detecting means for detecting a stroke change of the brake operating means;
Regenerative brake control means for controlling the regenerative braking force by the regenerative brake means based on the detection result of the brake operation detection means;
Power storage means for storing electric power generated by the operation of the regenerative brake means;
A remaining capacity detecting means for detecting the remaining capacity of the power storage means,
The regenerative brake control means includes a first period control means for controlling the regenerative brake means when a stroke change at the start of the braking operation of the brake operation means is detected by the brake operation detection means, and the braking operation is continuing. in, and a second time period control means for controlling the pulling Subsequently the regenerative brake unit to control by the first period control means,
The first period control means controls the regenerative braking means so that the regenerative braking force increases as the stroke change in the braking force increasing direction detected by the brake operation detecting means increases.
The second period control means is configured to reduce the regenerative braking force so that the regenerative braking force is reduced when the remaining capacity detected by the remaining capacity detection means is greater than or equal to a predetermined value, as compared with the control by the first period control means. The means is controlled.

  The “stroke change” here refers to at least one of the stroke change amount and the stroke change speed. Further, the “regenerative braking force” here refers to the braking force by the regenerative braking means.

Next, the invention according to claim 2 is the invention according to claim 1,
When the regenerative braking force reduction control is performed, the second period control unit performs control so that the amount of decrease in the regenerative braking force increases as the remaining capacity detected by the remaining capacity detection unit increases. And

Further, the invention according to claim 3 is the invention according to claim 1 or 2,
The first period control means sets the peak value of the regenerative braking force based on the magnitude of the stroke change at the start of the braking operation detected by the brake operation detecting means, so that the peak value is reached. Means for controlling the regenerative braking means so as to increase the regenerative braking force;
The brake system includes:
Peak arrival determination means for determining whether or not the regenerative braking force controlled by the first period control means has reached the peak value;
The second period control unit controls the regenerative braking force after the peak arrival determination unit determines that the regenerative braking force has reached the peak value.

The invention according to claim 4 is the invention according to any one of claims 1 to 3,
The second period control means is controlled by the brake operation detection means when the remaining capacity detected by the remaining capacity detection means is controlled to maintain the regenerative braking force by being less than the predetermined value. Control is performed so that the regenerative braking force is maintained even when a stroke change that decreases power is detected.

Furthermore, the invention according to claim 5 is the invention according to any one of claims 1 to 4,
When the remaining capacity detected by the remaining capacity detecting means is greater than or equal to the predetermined value and the second period control means is performing reduction control of the regenerative braking force, the second period control means applies braking force by the brake operation detecting means. Control is performed so as to maintain the regenerative braking force even when an increasing stroke change is detected.

Furthermore, the invention according to claim 6 is the invention according to any one of claims 1 to 5,
A storage control means for controlling a storage state of the storage means;
The power storage control means sets the remaining capacity of the power storage means to a predetermined value so that the power storage means can accept the electric power generated when the regenerative brake means operates except when the regenerative brake means operates. It is characterized by maintaining below the threshold value.

The invention according to claim 7 is the invention according to any one of claims 1 to 6,
A turning state detecting means for detecting whether or not the vehicle is turning;
When the turning state detecting means detects the turning state of the vehicle, the second period control means is configured to reduce the regenerative braking force even if the remaining capacity detected by the remaining capacity detecting means is greater than or equal to the predetermined value. It is characterized by maintaining.

Furthermore, the invention according to claim 8 is the invention according to any one of claims 1 to 7,
Further comprising downhill state detecting means for detecting whether the vehicle is in a downhill state,
The second period control means, when the downhill state of the vehicle is detected by the downhill state detection means, even if the remaining capacity detected by the remaining capacity detection means is equal to or greater than the predetermined value. It is characterized by maintaining power.

  According to the first aspect of the present invention, in the non-cooperative brake system in which the friction brake unit and the regenerative brake unit are individually operated without cooperation, the control of the regenerative brake unit is performed when the brake operation is started. The regenerative braking force is increased so as to increase as the stroke change in the braking force increasing direction increases. Thereafter, the regenerative braking force is decreased when the remaining capacity of the power storage means is a predetermined value or more. Therefore, when the remaining capacity of the power storage means is less than the predetermined value and the power storage means can sufficiently accept the regenerative power, the regenerative braking force by the control at the start of the brake operation is maintained and the regenerative braking force is maintained thereafter. Energy can be used effectively. On the other hand, when the remaining capacity of the power storage means is equal to or greater than the predetermined value and the regenerative power that can be accepted by the power storage means is small, the regenerative braking force by the control at the start of the brake operation is subsequently reduced to protect the power storage means. At the time of starting the braking operation, a regenerative braking force according to the driver's braking request can be obtained. Therefore, according to the uncoordinated brake system according to the present invention, it is possible to reliably prevent the driver from feeling uncomfortable during the brake operation while effectively using energy by using the regenerative brake means.

  According to the invention of claim 2 of the present application, when the regenerative braking force is subsequently reduced by the control at the start of the brake operation, the amount of decrease in the regenerative braking force is controlled to increase as the remaining capacity of the power storage means increases. Therefore, the power storage means can be effectively protected.

  According to the invention of claim 3 of the present application, the peak value of the regenerative braking force is set based on the magnitude of the stroke change at the start of the braking operation, and always reaches the peak value regardless of the remaining capacity of the power storage means. Since the regenerative braking force is controlled as described above, the driver does not always feel uncomfortable when operating the brake.

  In the invention of claim 4 of the present application, when the remaining capacity of the power storage means is controlled to maintain the regenerative braking force by being less than the predetermined value, even when a braking operation for reducing the braking force is performed. The regenerative braking force is controlled to be maintained. According to the fourth aspect of the present invention, when the power storage means can sufficiently accept the regenerative power, the regenerative brake means can be used as much as possible to further effectively use the regenerative energy. Even if the regenerative braking force is maintained when the braking operation for reducing the braking force is performed in this way, the friction braking force is reduced according to the braking operation, thereby reducing the total braking force. A person's discomfort can be suppressed.

  In the invention of claim 5 of the present application, even when the regenerative braking force reduction control is performed because the remaining capacity of the power storage means is equal to or greater than the predetermined value, when a braking operation for increasing the braking force is performed. The regenerative braking force reduction control is interrupted, and the regenerative braking force is controlled to be maintained. At this time, the frictional braking force increases in response to the brake operation, thereby increasing the total braking force. Therefore, it is possible to prevent the driver from feeling that the braking force is insufficient and to store the power by not increasing the regenerative braking force. Means can be protected.

  According to the invention of claim 6 of the present application, since the remaining capacity of the power storage means is maintained below a predetermined threshold so that the power storage means can accept regenerative power except during the operation of the regenerative brake, Thus, the regenerative braking force according to the braking request can be obtained with certainty.

  According to the seventh aspect of the present invention, even when the remaining capacity of the power storage means is equal to or greater than the predetermined value, the regenerative braking force is controlled to be maintained when the vehicle is turning. The running stability can be maintained.

  According to the invention of claim 8 of the present application, even when the remaining capacity of the power storage means is equal to or greater than the predetermined value, the vehicle is controlled to maintain the regenerative braking force when the vehicle is on a downhill. It is possible to maintain running stability on the slope.

1 is a system diagram showing a vehicle brake system according to an embodiment of the present invention. It is a flowchart of an example of the control operation which the controller shown in FIG. 1 performs. It is a figure which shows an example of the map used for the setting of the peak value Tmax of regenerative torque. It is a figure which shows an example of the map used for the setting of reduction amount (DELTA) T of regenerative torque. It is a time chart which shows an example of a time-dependent change of the regenerative torque controlled by the controller shown in FIG. In the case where the regenerative torque is controlled to be maintained at the peak value Tmax, when the depression amount of the brake pedal increases or decreases, the time chart showing the change with time of the regenerative torque controlled by the brake system according to another embodiment It is. In the case where the regenerative torque is controlled to decrease from the peak value Tmax, when the amount of depression of the brake pedal increases or decreases, the time indicating the change over time of the regenerative torque controlled by the brake system according to another embodiment It is a chart. It is a graph which shows a time-dependent change of the regenerative torque at the time of performing each control set up in the test about a driver's feeling of deceleration. It is a graph which shows the driver | operator's feeling of deceleration obtained when each control shown in FIG. 8 is performed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  First, an experiment conducted by the inventor of the present application will be described for the purpose of developing a non-cooperative brake system that can always obtain a sufficient feeling of deceleration during brake operation.

  In this experiment, a regenerative braking force (hereinafter also referred to as “regenerative torque”) by the motor generator is controlled in an electric vehicle equipped with a motor generator (regenerative brake) as a travel drive source and employing a non-cooperative brake system. A plurality of methods were set, and the degree of deceleration felt by the driver when these methods were used was confirmed.

  Specifically, control A, control B, and control C were set as methods for controlling the regenerative torque. As shown in FIG. 8, the control A to control C are set so that the cumulative values of the regenerative torque in a predetermined time from the start of the brake operation are equal to each other, but the peak value of the regenerative torque at the initial stage of the brake operation is They are different from each other. Specifically, in control A, the peak value of the regenerative torque was set to the highest value, and after reaching the peak value, the regenerative torque was controlled to decrease rapidly. In the control B, the peak value of the regenerative torque is set lower than that in the control A, and the reduction of the regenerative torque after reaching the peak value is set to be relatively gradual. Further, in the control C, the peak value of the regenerative torque is set to the lowest value, and the decrease of the regenerative torque after reaching the peak value is set to be the slowest.

  As shown in FIG. 9, as a result of this experiment, the feeling of deceleration obtained by the driver is large in the order of control A, control B, and control C. In particular, the feeling of deceleration obtained when control A is performed is It was confirmed that it was larger than the control. From this experimental result, if the inventor of the present application sets the peak value of the regenerative torque at the initial stage of the brake operation to be large, the driver can obtain a sufficient feeling of deceleration even if the regenerative torque is sharply reduced after reaching the peak value. I found that I did not feel strange when operating the brakes.

  The present invention has been obtained by paying attention to this point, and hereinafter, embodiments of the present invention will be specifically described.

  FIG. 1 shows a vehicle brake system 10 according to an embodiment of the present invention. The brake system 10 operates the friction brakes 12 and 14 and the regenerative brake including the motor generator 40 in a non-cooperative manner in accordance with a change in stroke of the brake pedal 22.

  In the present embodiment, the vehicle 1 on which the brake system 10 is mounted is an electric vehicle that can travel with a driving force obtained by the motor generator 40 operating as an electric motor. When the vehicle 1 decelerates, the motor generator 40 generates regenerative power by operating as a generator through deceleration regenerative control, and functions as a regenerative brake that uses rotational resistance generated during this power generation. .

  As the friction brakes 12 and 14, for example, disc brakes are used. However, friction brakes other than the disc brakes may be used as long as they generate braking force using frictional resistance, for example, drum brakes are used. May be. The friction brakes 12 and 14 are provided for each wheel on the front wheel 2 and the rear wheel 4, and are connected to the brake pedal 22 via a vacuum booster 24, a master cylinder 26, and hydraulic paths 16 and 18.

  The vacuum booster 24 uses the negative pressure supplied from the vacuum control system 28 to increase the pedal pressure of the brake pedal 22 and outputs the increased pedal pressure to the master cylinder 26. The vacuum control system 28 is a device that generates a negative pressure with a vacuum pump, and the negative pressure supplied from the vacuum control system 28 to the vacuum booster 24 is determined based on a control signal from a controller 30 described later. Controlled so as not to fall below the value.

  The master cylinder 26 supplies the hydraulic pressure corresponding to the pedal effort pressure input from the vacuum booster 24 to the hydraulic path 16 for front wheel braking and the hydraulic path 18 for rear wheel braking, and thereby the hydraulic path for front wheel braking. The hydraulic pressure is supplied to the front wheel friction brake 12 via 16, and the hydraulic pressure is supplied to the rear wheel friction brake 14 via the rear wheel braking hydraulic path 18. 14 is activated.

  In the present embodiment, the motor generator 40 is drivingly connected to the front wheels 2. The motor generator 40 operates as an electric motor when power supplied from the battery 42 is supplied via the inverter 44, and the driving force of the motor generator 40 generated thereby is transmitted to the front wheels 2. It becomes possible to run. On the other hand, when the motor generator 40 operates as a generator, the regenerative power generated thereby is supplied to the battery 42 via the inverter 44, thereby charging the battery 42. The operation of the motor generator 40 as an electric motor or a generator is controlled by controlling the inverter 44 by the controller 30 described later.

  The controller 30 includes an accelerator pedal stroke sensor 50 that detects the amount of depression of the accelerator pedal 20, a brake pedal stroke sensor 52 that detects the amount of depression of the brake pedal 22, and current and voltage for estimating the remaining capacity of the battery 42 by the controller 30. Are electrically connected to an SOC estimation sensor 54 that detects various information such as temperature, a steering angle sensor 56 that detects the steering angle of the front wheel 2, and a gradient sensor 58 that detects the gradient of the road surface. Arithmetic processing is performed based on a signal sent from the sensor, and a control signal is output to the vacuum control system 28 and the inverter 44.

  When the brake pedal 22 is depressed by the driver, the controller 30 controls the friction braking force by the friction brakes 12 and 14 and the inverter 44 by controlling the inverter 44 based on the detection result of the brake pedal stroke sensor 52. The regenerative braking force by 40 is controlled.

  Since the controller 30 employs a non-cooperative brake system, the control of the friction braking force and the control of the regenerative braking force are independently performed without coordination. For this reason, if control for decreasing the regenerative braking force is performed, for example, when the remaining capacity of the battery 42 is large and it is difficult to accept regenerative power, control for increasing the friction braking force is performed to compensate for this. Therefore, the total braking force is reduced, and the driver may feel uncomfortable when operating the brake. In order to solve this problem, in the present embodiment, control of the regenerative braking force (regenerative torque) by the controller 30 is performed as follows.

  First, when a change in stroke at the start of the brake operation is detected by the brake pedal stroke sensor 52, the regenerative torque T is controlled to increase as the detected change in stroke in the braking force increasing direction increases. The “stroke change” here refers to at least one of the stroke change amount and the stroke change speed.

  Specifically, the peak value Tmax of the regenerative torque T is set by the brake pedal stroke sensor 52 based on the magnitude of the stroke change at the start of the brake operation, and the regenerative torque T is increased so as to increase until the peak value Tmax is reached. Is controlled. With this control, the braking force according to the driver's braking request can be obtained reliably in the initial stage of the braking operation, so that even if the regenerative torque T subsequently decreases, the driver can obtain a sufficient feeling of deceleration. And you don't feel uncomfortable when operating the brakes.

  The control of the regenerative torque T at the initial stage of the brake operation is executed whenever the stroke change at the start of the brake operation is detected by the brake pedal stroke sensor 52. Therefore, it is necessary to ensure that the regenerative power generated by such control is received by the battery 42.

  Therefore, the controller 30 maintains the remaining capacity of the battery 42 below a predetermined threshold value X so that the battery 42 can reliably accept the regenerative power except when the motor generator 40 is operating as a generator. To control. By controlling the power storage state of the battery 42 in this way, when the brake operation is started, the above-described control of the regenerative torque T at the initial stage of the brake operation can be reliably performed. The threshold value X is set, for example, to a value obtained by subtracting a capacity corresponding to regenerative power for three brake operations from a maximum value Z (remaining capacity when fully charged) of the battery 42. The storage state of the battery 42 is controlled by the inverter 44.

  After the regenerative torque T reaches the peak value Tmax, the regenerative torque T is controlled according to the remaining capacity of the battery 42.

  Specifically, after the peak value of the regenerative torque T is reached, if the remaining capacity of the battery 42 is less than a predetermined value Y that can sufficiently accept the regenerative power, the regenerative torque is represented by the symbol a in FIG. T is controlled so as to be maintained, whereby effective use of regenerative energy can be achieved. Here, the predetermined value Y is set to a value larger than the threshold value X, for example, but may be set to the same value as the threshold value X.

  On the other hand, if the remaining capacity of the battery 42 is equal to or greater than the predetermined value Y after the peak value of the regenerative torque T is reached, the regenerative torque T is controlled so as to decrease as indicated by symbols b to d in FIG. When the reduction control of the regenerative torque T is performed, the reduction amount ΔT of the regenerative torque T is controlled so as to increase as the remaining capacity of the battery 42 increases. By such control, it is possible to appropriately protect the battery 42 by avoiding excessive supply of regenerative power to the battery 42. Further, in this case, the total braking force including the friction braking force is reduced by reducing the regenerative torque T. However, as described above, a sufficient braking force is applied at the initial stage of the brake operation, so that the driver can It is possible to prevent the user from feeling strange during operation.

  Next, an example of a control operation when the controller 30 controls the regenerative torque T will be described with reference to the flowchart of FIG.

  First, in step S1, various information relating to the driving state of the vehicle 1 is read based on an input signal to the controller 60. Specifically, the output values of the accelerator pedal stroke sensor 50, the brake pedal stroke sensor 52, the SOC estimation sensor 54, the steering angle sensor 56, and the gradient sensor 58 are read.

  In the next step S2, it is determined whether or not the accelerator pedal 20 is depressed based on the output value of the accelerator pedal stroke sensor 50 read in step S1. Note that the determination in step S2 may be performed based on the output value of an accelerator switch that detects on / off of the accelerator pedal 20, instead of the output value of the accelerator pedal stroke sensor 50.

  If the result of determination in step S2 is that the accelerator pedal 20 is depressed, it is considered that there is no braking request from the driver, and the flag F1 used for determining whether or not the peak value Tmax of the regenerative torque has been set, Both the flag F2 used for determining whether or not the torque T has reached the peak value Tmax is set to “0” (step S15), and the process ends without the regenerative braking by the motor generator 40 being activated.

  On the other hand, if the result of determination in step S2 is that the accelerator pedal 20 is not depressed, the process proceeds to step S3.

  In step S3, it is determined whether or not the brake pedal 22 is depressed based on the output value of the brake pedal stroke sensor 52 read in step S1. Note that the determination in step S3 may be performed based on the output value of the brake switch that detects the on / off state of the brake pedal 22, instead of the output value of the brake pedal stroke sensor 52.

  If the result of determination in step S3 is that the brake pedal 22 has not been depressed, it is considered that there is no braking request from the driver, and both the flag F1 and flag F2 are set to "0" (step In step S16, the regenerative torque T is set to a minimum value Tmin that causes minimum regenerative braking corresponding to engine braking (step S17), and the output value Tmin is output to the inverter 44 (step S13).

  On the other hand, if the result of determination in step S3 is that the brake pedal 22 is depressed, it is determined whether or not the flag F1 is set to “1” (step S4).

  As a result of the determination in step S4, the process proceeds to step S5 only when the flag F1 is set to “0”. When the flag F1 is set to “1”, the process skips steps S5 and S6 and proceeds to step S7. move on.

  In step S5, the peak value Tmax of the regenerative torque is set based on the depression amount Bst of the brake pedal 22 detected by the brake pedal stroke sensor 52 and the increasing speed ΔBst of the depression amount Bst. Specifically, the peak value Tmax is set so as to increase as the stepping amount Bst increases and to increase as the stepping amount increase rate ΔBst increases, for example, using the map shown in FIG. Thereby, the peak value Tmax of the regenerative torque can be set to a value according to the driver's braking request. When the peak value Tmax is set in this way, the flag F1 is set to “1” in the subsequent step S6, and then the process proceeds to step S7.

  In step S7, it is determined whether or not the regenerative torque T has reached the peak value Tmax set in step S5.

  Immediately after the peak value Tmax is set, the regenerative torque T has not reached the peak value Tmax, and thus the process proceeds to step S14 through the determination in step S7. In step S14, it is determined that the flag F2 is not “1”. The peak value Tmax is output to the inverter 44 as the output value of the torque T (step S13). In this case, the same processing is repeated until the regenerative torque T reaches the peak value Tmax, whereby the regenerative torque T reaches the peak value Tmax at the beginning of the brake operation. Therefore, the regenerative torque T according to the braking request is activated at the initial stage of the brake operation, so that the driver does not feel uncomfortable during the brake operation.

  On the other hand, when the regenerative torque T reaches the peak value Tmax, the flag F2 is set to “1” in step S8 through the determination in step S7, and then the process proceeds to step S9.

  In step S9, it is determined based on the output value of the gradient sensor 58 read in step S1 whether or not the vehicle 1 is descending. In step S10, the output of the rudder angle sensor 56 read in step S1. Based on the value, it is determined whether or not the vehicle 1 is cornering. Note that the determination in step S9 may be performed based on another sensor that can detect the downhill state of the vehicle (for example, an acceleration sensor that detects vertical acceleration) instead of the output value of the gradient sensor 58. The determination in step S10 may be performed based on another sensor that can detect the turning state of the vehicle (for example, an acceleration sensor that detects acceleration in the vehicle width direction) instead of the output value of the steering angle sensor 56.

  As a result of the determination in step S9 and step S10, when the vehicle 1 is descending or cornering, the regeneration torque T is reduced to the inverter without executing the reduction control of the regeneration torque T in step S11 and step S12. (Step S13). As a result, the running stability of the vehicle 1 during downhill or cornering can be maintained.

  On the other hand, as a result of the determination in step S9 and step S10, when the vehicle 1 is not downhill or cornering, the reduction control of the regenerative torque T in step S11 and step S12 is executed.

  In step S11, a reduction amount ΔT of the regenerative torque T is set. Specifically, for example, using the map shown in FIG. 4, the larger the remaining capacity of the battery 42 estimated based on the detection value of the SOC estimation sensor 54, that is, the smaller the regenerative power that the battery 42 can accept. The regenerative torque reduction amount ΔT is set large. As a result, when the regenerative power that can be received by the battery 42 is small, the regenerative torque T is greatly reduced to avoid excessive supply of regenerative power to the battery 12 and appropriately protect the battery 42. be able to.

  In the subsequent step S12, the regenerative torque T is subtracted by the amount of decrease ΔT set in step S11, and the value after this subtraction is output to the inverter 44 (step S13). In this way, even if the regenerative torque T is decreased after reaching the peak value Tmax, the driver hardly feels that the braking force is insufficient as described above, and does not feel uncomfortable during the brake operation.

  Note that when the depression amount Bst of the brake pedal 22 increases or decreases during the execution of the control operation shown in FIG. 2, the regenerative torque T may be controlled to increase or decrease accordingly.

  However, it is not preferable from the viewpoint of energy efficiency and protection of the battery 42 to always increase the regenerative torque T when the stepping amount Bst increases or to always decrease the regenerative torque T when the stepping amount Bst decreases. There is.

  Based on this viewpoint, another embodiment of the present invention will be described with reference to FIGS. 6 and 7. In each of the embodiments shown in FIGS. 6 and 7, the regenerative torque T is basically controlled by the above-described controller 30 in the same manner as in the above-described embodiment, but the brake is applied after the regenerative torque T reaches the peak value Tmax. The control operation when the depression amount of the pedal 22 is increased or decreased is different from that of the above-described embodiment.

  Specifically, in the embodiment shown in FIG. 6, when the remaining capacity of the battery 42 is less than the predetermined value Y and is controlled to maintain the regenerative torque T, the depression amount Bst of the brake pedal 22 is When it increases, the regenerative torque T is controlled to increase accordingly. Thereby, regenerative braking according to the driver's braking request can be obtained. On the other hand, when the regenerative torque T is controlled to be maintained in the same manner, the regenerative torque T is controlled to be maintained when the depression amount Bst of the brake pedal 22 decreases. Thus, when the battery 42 can sufficiently accept the regenerative power, the regenerative braking can be used as much as possible to further effectively use the regenerative energy. Even if the regenerative braking force is maintained when the braking operation for reducing the braking force is performed in this way, the friction braking force is reduced according to the braking operation, thereby reducing the total braking force. A person's discomfort can be suppressed.

  In the embodiment shown in FIG. 7, when the decrease amount Bst of the brake pedal 22 is decreased when the regenerative torque T is being controlled to be decreased because the remaining capacity of the battery 42 is equal to or greater than the predetermined value Y, Accordingly, the regenerative torque T is controlled to decrease. Thereby, regenerative braking can be reduced in accordance with a decrease in the driver's braking request. On the other hand, when the reduction control of the regenerative torque T is similarly performed, the regenerative torque T is controlled to be maintained when the depression amount Bst of the brake pedal 22 increases. As a result, the reduction control of the regenerative torque T is interrupted, and the friction braking force increases in accordance with the brake operation, thereby increasing the total braking force, thereby suppressing the driver from feeling that the braking force is insufficient. However, the battery 42 can be protected by not increasing the regenerative torque T.

  While the present invention has been described with reference to the above-described embodiments, the present invention is not limited to the above-described embodiments.

  For example, in the above-described embodiment, the case where the present invention is applied to an electric vehicle has been described. However, the present invention is an electric vehicle as long as the vehicle is equipped with a brake system that operates a friction brake and a regenerative brake in an uncoordinated manner. It can also be applied to other vehicles (for example, hybrid vehicles).

  As described above, according to the present invention, in the non-cooperative brake system, it is possible to always prevent the driver from feeling uncomfortable when operating the brake while effectively using energy by using the regenerative brake. There is a possibility of being suitably used in the field of manufacturing industries of vehicles such as electric vehicles or hybrid vehicles that employ a non-cooperative brake system.

1: vehicle, 10: brake system, 12, 14: friction brake, 22: brake pedal, 30: controller, 40: motor generator (regenerative brake means), 42: battery (power storage means), 52: brake pedal stroke sensor, 54: SOC estimation sensor, 56: Rudder angle sensor, 58: Gradient sensor.

Claims (8)

A brake system for a vehicle that operates the friction brake means and the regenerative brake means in a non-cooperative manner in accordance with a stroke change of the brake operation means,
Brake operation detecting means for detecting a stroke change of the brake operating means;
Regenerative brake control means for controlling the regenerative braking force by the regenerative brake means based on the detection result of the brake operation detection means;
Power storage means for storing electric power generated by the operation of the regenerative brake means;
A remaining capacity detecting means for detecting the remaining capacity of the power storage means,
The regenerative brake control means includes a first period control means for controlling the regenerative brake means when a stroke change at the start of the braking operation of the brake operation means is detected by the brake operation detection means, and the braking operation is continuing. in, and a second time period control means for controlling the pulling Subsequently the regenerative brake unit to control by the first period control means,
The first period control means controls the regenerative braking means so that the regenerative braking force increases as the stroke change in the braking force increasing direction detected by the brake operation detecting means increases.
The second period control means is configured to reduce the regenerative braking force so that the regenerative braking force is reduced when the remaining capacity detected by the remaining capacity detection means is greater than or equal to a predetermined value, as compared with the control by the first period control means. A vehicle brake system characterized by controlling the means.   When the regenerative braking force reduction control is performed, the second period control unit performs control so that the amount of decrease in the regenerative braking force increases as the remaining capacity detected by the remaining capacity detection unit increases. The vehicle brake system according to claim 1. The first period control means is means for setting a peak value of the regenerative braking force based on the magnitude of the stroke change detected by the brake operation detection means,
The brake system includes:
Regenerative braking force detection means for detecting regenerative braking force by the regenerative braking means;
Peak arrival determination means for determining whether or not the regenerative braking force detected by the regenerative braking force detection means has reached the peak value set by the first period control means;
The second period control means controls the regenerative braking force after the peak arrival judging means determines that the regenerative braking force has reached the peak value. 2. The vehicle brake system according to 2.   The second period control means is controlled by the brake operation detection means when the remaining capacity detected by the remaining capacity detection means is controlled to maintain the regenerative braking force by being less than the predetermined value. 4. The vehicle brake system according to claim 1, wherein the regenerative braking force is controlled to be maintained even when a stroke change that decreases power is detected. 5.   When the remaining capacity detected by the remaining capacity detecting means is greater than or equal to the predetermined value and the second period control means is performing reduction control of the regenerative braking force, the second period control means applies braking force by the brake operation detecting means. 5. The vehicle brake system according to claim 1, wherein control is performed so as to maintain the regenerative braking force even when an increasing stroke change is detected. 6. A storage control means for controlling a storage state of the storage means;
The power storage control means sets the remaining capacity of the power storage means to a predetermined value so that the power storage means can accept the electric power generated when the regenerative brake means operates except when the regenerative brake means operates. The vehicle brake system according to any one of claims 1 to 5, wherein the brake system is maintained below a threshold value. A turning state detecting means for detecting whether or not the vehicle is turning;
When the turning state detecting means detects the turning state of the vehicle, the second period control means is configured to reduce the regenerative braking force even if the remaining capacity detected by the remaining capacity detecting means is greater than or equal to the predetermined value. The vehicle brake system according to any one of claims 1 to 6, wherein the vehicle brake system is maintained. Further comprising downhill state detecting means for detecting whether the vehicle is in a downhill state,
The second period control means, when the downhill state of the vehicle is detected by the downhill state detection means, even if the remaining capacity detected by the remaining capacity detection means is equal to or greater than the predetermined value. The vehicle braking system according to any one of claims 1 to 7, wherein power is maintained.

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