JP2503818B2 - Vehicle brake energy regeneration device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle brake energy regenerating apparatus for recovering deceleration energy of a vehicle and using it as start / acceleration energy.

[0002]

2. Description of the Related Art Of the kinetic energy lost during deceleration of a vehicle, a portion mainly dissipated as heat (brake and engine) is recovered as hydraulic pressure and accumulated in an accumulator.
A deceleration energy recovery device for a vehicle equipped with a PTO (Power-take-off) output device or an axle provided with a transfer that uses the accumulated energy as the starting energy and acceleration energy of the vehicle has been known in the past. In the early 1970s, German M.S. A. N. Various researches and developments have been made in Europe and the United States, such as the start of research, etc.
No. 0 etc.

In the vehicle brake energy regenerating apparatus disclosed in Japanese Patent Application No. 63-272750 by the present inventor, if the regenerative braking by hydraulic pressure alone cannot cover all the necessary braking torque, electromagnetic proportional air pressure control is required. The valve is controlled to compensate for the insufficient brake torque with air brakes.

The purpose of this is to make the relationship between the amount of depression of the brake pedal and the brake torque to be generated constant so that the driver does not feel uncomfortable with the brake.

That is, the pump capacity required for the pump / motor is determined from the required brake torque determined by the amount of depression of the brake pedal in accordance with the pressure of the hydraulic circuit, and the required pump capacity exceeds the maximum rated capacity of the pump / motor. In this case, the pump capacity of the pump / motor is maximized, and the insufficient braking force is controlled by the air brake device using an electromagnetic proportional air pressure control valve.

[0006]

In the case of such a conventional technique, even if the pump capacity of the pump / motor is determined by the pressure of the hydraulic circuit, the capacity variable control instruction is issued after the pump / motor response characteristic is given. It actually takes time to reach the target pump displacement, which causes a delay in the generation of the braking force, and it is necessary to further depress the brake pedal when a strong brake is required.

Therefore, according to the present invention, the hydraulic circuit, the brake pedal depression amount detecting means, the air pressure proportional control valve, the air brake device, and the required brake torque detected by the detecting means are the pumps of the hydraulic circuit. When the current hydraulic brake torque generated by the motor is exceeded, the pump capacity of the pump / motor is maximized and the insufficient brake torque is compensated by the air brake device by controlling the proportional control valve. In the braking energy regeneration device of the vehicle equipped with the means, it is possible to always generate the required braking force with a response equal to or higher than that of a normal air braking device, but in the slow braking region where the response is not so important. The purpose is to prioritize regeneration efficiency as before.

[0008]

To achieve the above object, in the vehicle brake energy regenerating apparatus according to the present invention, while the control means is in the slow brake region where the brake pedal depression amount is equal to or less than a predetermined value, The pump / motor is controlled to generate a brake torque only by the hydraulic circuit, and when the brake pedal depression amount exceeds a predetermined value, the required brake torque is shared according to a predetermined distribution ratio of front wheels and rear wheels determined by the axle weight. The brake torque to be applied is determined in advance, and when the current hydraulic brake torque exceeds the rear wheel burden brake torque, all the current hydraulic brake torque is applied to the rear wheels and the insufficient brake torque is applied to the air brake device. Is applied to the front wheels by the current hydraulic brake torque, and the current hydraulic brake torque is equal to or less than the rear wheel burden brake torque, the front wheel burden brake torque is applied. Is generated by the air brake device and applied to the front wheels, all the current hydraulic brake torque is applied to the rear wheels, and the insufficient brake torque obtained by subtracting the current hydraulic brake torque from the rear wheel burden brake torque is applied to the air brake device. It is designed to be given to the rear wheels.

[0009]

The present invention will be described with reference to the schematic view of FIG. 1. In the control means (C / U) 64, the depression amount of the brake pedal 57 is below a predetermined value based on the output signal of the sensor 59 as the brake pedal depression amount detecting means. It is determined whether or not it is in the shallow pedaling amount region, that is, in the gentle braking region. As a result, when it is found that it is in the gentle braking region, the pump / motor 14 is controlled to operate only the regenerative brake. Hydraulic circuit (high pressure accumulator 26, circuit valve 25, pump / motor 1
4, which is composed of the low pressure accumulator 27) alone to generate the brake torque.

When it is determined that the amount of depression of the brake pedal 57 exceeds the gentle brake area, the control means 64 causes the pump hydraulic capacity of the pump / motor 14 during braking to generate the current hydraulic brake generated by the hydraulic circuit. The torque is obtained, and the required brake torque is obtained from the output signal of the brake pedal depression amount sensor 59. Then, the brake torque to be borne is determined in advance according to a predetermined distribution ratio of the front wheels and the rear wheels that determines the required brake torque determined by the axial load.

When the required brake torque is equal to or less than the current hydraulic brake torque, the control means 64 applies only the hydraulic brake torque corresponding to the required pump torque to the pump / motor 14 as in the normal vehicle. Hang on a circle.

Further, when the required brake torque exceeds the current hydraulic brake torque, the pump / motor 14 is controlled to fix the pump capacity to the maximum, and the current hydraulic brake torque is further applied to the rear wheel bearing brake torque. If the current hydraulic brake torque is exceeded, all the current hydraulic brake torque is applied to the rear wheels, and the insufficient brake torque (= required brake torque-current hydraulic brake torque) is controlled by the air brake device 72 by controlling the air pressure proportional control valve 70. Generate and give only to the front wheels.

On the other hand, when the current hydraulic brake torque is below the required brake torque and is equal to or less than the rear wheel-borne brake torque, the air brake device 72 is controlled by controlling only the front-wheel-borne brake torque by the air pressure proportional control valve 70.
Is applied to the front wheels and all the current hydraulic brake torque is applied to the rear wheels, and the insufficient braking torque in this case (= the rear wheel-bearing brake torque-the current hydraulic brake torque) is applied to the air pressure proportional control valve 70. It is generated by the air brake device 72 by being controlled and given to the rear wheels.

In this way, in the slow braking region, only the regenerative brake is operated to give priority to the regenerative efficiency, and in the slow braking region and thereafter, the insufficient braking torque when the required braking torque during braking is large is hydraulically adjusted. By variably controlling the regenerative brake and the front and rear wheel air brakes, the responsiveness of the entire braking system that combines the regenerative brake and the air brake, and the front and rear wheels when a large braking force is generated It is possible to ensure vehicle stability by optimally distributing the braking force.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vehicle brake energy regenerating apparatus according to the present invention will be described below.

FIG. 2 is an overall configuration diagram of an embodiment of a vehicle brake energy regeneration system according to the present invention. 1 is an engine, 2 is a load sensor of the engine 1, and 3 is a response to depression of an accelerator pedal 54. The step motors 4 are controlled by the step motor 3 to set the fuel supply amount to the engine 1, and the injection (injection) pump levers connected to the load sensor 2 are output from the T / M (transmission), 6 is a gear shift actuator that automatically shifts a gear stage (not shown) of T / M 5, 7 is a clutch actuator that automatically connects and disconnects a clutch (not shown), and 8 is T / M
5 is a PTO device engaged with 5, 9 is a propeller shaft forming a drive system of a wheel together with axle 10 and wheels 11, 12 is a PTO shaft of the PTO device 8, 13 is an electromagnetic clutch, 14 is a PTO shaft 12 and an electromagnetic clutch. A well-known variable-capacity oblique axial type which is engaged with the PTO device 8 via the piston 13 and is combined with the tilt angle control pilot pipe 15, the tilt angle control electromagnetic proportional control valve 16 and the tilt angle control piston 17 A piston pump / motor 14a is a suction port and 14b is a discharge port. Also, 80 is a pump
The tilt angle sensor detects the tilt angle of the motor 14.

Here, the pump / motor 14 is shown in FIG.
Referring to (a) and FIG. 3 (b) which is an arrow view of FIG. 3 (a), the output shaft 14c is engaged with the center hole of the cylinder block 14f as shown in FIG. 3 (a). The shaft 14d is inserted, and the opposite side is engaged with the tilt angle control piston 17 via the port plate 14h. Also, around the cylinder block 14f,
A plurality of cylinders 14g are provided, and a piston 14e engaged with an output shaft 14c is slidably inserted into one end of the cylinder 14g, and the other side thereof is connected via a port plate 14h to the same via a port plate 14h (b). ) Communicates with the suction port 14a or the discharge port 14b.

The tilt angle control piston 17 is a hydraulic oil supplied from the tilt angle control pilot pipe 15 to the lower portion of the piston 17 in proportion to the control current supplied to the tilt angle control electromagnetic proportional control valve 16. Alternatively, the position is changed in the vertical direction in the figure by being pushed by the hydraulic oil in the hydraulic piping 20 or 21. Therefore, the cylinder block 14f, the piston 1
4e, the shaft 14d, and the port plate 14h, the shaft 14c engaged with the output shaft 14c.
The angle changes with the vertical movement of the tilt angle control piston 17 about the spherical end of d (in this case, the output shaft 14c).
The angle θ formed by the shaft 14d and the shaft 14d is called a tilt angle).

FIG. 1A shows a tilt angle control solenoid proportional control valve 16
At the time when the maximum control current is applied to the output shaft 14c, and since the tilt angle becomes the maximum, the discharge amount per one rotation of the output shaft 14c is the maximum. Tilt angle control When the control current of the solenoid proportional control valve 16 is 0, the tilt angle is "0" as shown by the dotted line.
And the discharge amount is also “0”.

Returning to FIG. 2, reference numeral 18 denotes a high pressure relief valve for releasing the accumulated pressure of a high pressure accumulator 26, which will be described later, when the accumulated pressure exceeds a set value, and 19a, when the hydraulic oil supply pressure of the replenishing circuit exceeds the set value. , Low pressure relief valve to release this, 19b
Is a low-pressure relief valve for generating a pilot pressure necessary for causing the pump / motor 14 to perform a tilting operation on a tilting angle control pilot pipe 15, 20 is a suction side pipe of the pump / motor 14, and 21 is a pump / motor 14. Discharge side piping, 2
2 is a hydraulic oil supply pipe, 22a is a hydraulic oil return pipe, 2
3 is a high-pressure side pipe, 24 is a low-pressure side pipe, 25 is a circuit switching valve for switching the pipes 20 to 24, 26 is a high-pressure accumulator connected to the circuit switching valve 25 via the high-pressure side pipe 23, and 27 is a low-pressure pipe. The pump / motor 14 connected to the circuit switching valve 25 via the side pipe 24 and the circuit switching valve 2
5 is a low-pressure accumulator that forms a hydraulic circuit with the high-pressure accumulator 26.

The circuit switching valve 25 is used for the pump / motor 1
When the inlet / outlet of the pump 4 is fixed, it is necessary to switch the output between the pump and the motor. If an inverted piston pump / motor is used as the pump / motor 14, a circuit shut-off valve is used. You can also. These circuit switching valve and circuit cutoff valve can be collectively referred to as a circuit valve.

The switching operation of the piping by the circuit switching valve 25 will now be described. The electromagnets 25a and 25b thereof.
Are not energized, the valve position is the position shown in the center of the three valve positions and the four pipes 20, 21, 2
Connections 3 and 24 are broken.

When recovering the braking energy,
The valve position is switched to the electromagnet 25a side by energizing the electromagnet 25a. Then, the low pressure accumulator 27 can be communicated with the suction port 14a of the pump / motor 14 via the pipes 24 and 20, and the high pressure accumulator 26 can be communicated with the discharge port 14b of the pump / motor 14 via the pipes 23 and 21. . As a result, the hydraulic oil stored in the low-pressure accumulator 27 is suctioned / driven by the pump / motor 14 driven by the brake energy and functioning as a pump.
It is discharged and stored in the high-pressure accumulator 26.

On the contrary, when the pump / motor 14 functions as a motor, the electromagnet 25b of the circuit switching valve 25 is energized to switch the valve position to the electromagnet 25b side. Then
The low-pressure accumulator 27 can be connected to the discharge port 14 b of the pump / motor 14 via the pipes 24 and 21, and the high-pressure accumulator 26 can be connected to the suction port 14 a of the pump / motor 14 via the pipes 23 and 20. As a result, the hydraulic oil accumulated in the high-pressure accumulator 26 passes through the pipes 23 and 20 to rotate the pump / motor 14 as a motor, and then reaches the low-pressure accumulator 27 through the pipes 21 and 24, where it is stored. become.

28 is a hydraulic oil drain tank, 29 is a hydraulic oil filter, 30 is a hydraulic oil replenishing pump driven by the engine 1, and 31 and 32 are provided on the replenishing pipe 22 from the hydraulic circuit to the drain tank. The returned hydraulic oil is supplied to the hydraulic circuit and the pump / motor 14
Is a solenoid valve that supplies a pilot hydraulic pressure through a tilt angle control pilot pipe 15.

Next, 33 is a direct connection cooling relay switch, 3
4 is a water temperature sensor of the engine 1, 35 is a rotation speed sensor of the engine 1, 36 is an input shaft rotation speed sensor, 3
7 is a T / M5 clutch stroke sensor, 38 is a gear position sensor, 39 is a gear shift stroke sensor, 40
Is a vehicle speed sensor, 41 is a T / M5 oil temperature sensor, 42 is an exhaust brake control valve, and 43 is an exhaust brake valve (not shown).
, An air pipe 45 for supplying air pressure to the cylinder 43 via the exhaust brake control valve 42,
And 46, an oil amount detection limit switch provided in the drain tank 28, and 47, a pressure sensor for detecting the pressure of the hydraulic oil accumulated in the high-pressure accumulator 26.
The gear position sensor 38 and the gear shift stroke sensor 39 constitute a gear position detecting means.

Further, 49 is a driver seat, 50 is a leaving seat detection switch for detecting whether or not the driver has left the driver seat 49, 51 is a parking brake lever, 52 is a parking brake switch, and 53 is a brake energy regeneration device ( (Hereinafter referred to as RBS), 54 is an accelerator pedal, 55 is an idle position detection switch, 56 is an accelerator opening detection sensor, 57 is a brake pedal, 59 is a brake depression amount sensor, 60 is a gear select lever, and 61 is a slope. Starting assistance device (hereinafter,
HSA switch), 62 idle control switch, 63 indicators, 65 door switch, 66 key switch, 67 brake air piping, 68 brake air tank, 69 brake air pressure sensor, 70 electronic Air pressure proportional control valve or electromagnetic proportional pressure control valve (hereinafter described as electronic air pressure proportional control valve), 71 is an air pressure sensor, 74 is an air master, 64
Is based on the outputs of the above sensors and switches, etc.
It is a control unit (hereinafter abbreviated as C / U) as control means for controlling the motor 14 and the actuator to regenerate brake energy. The air brake device 7 is connected to the brake air tank 68 and the air master 74.
2 and the C / U 64 includes a memory (not shown) for storing programs, maps and various flags described below.

FIG. 4 shows the C / U 64 shown in FIGS. 1 and 2.
FIG. 3 is a flowchart of a program stored and executed in the embodiment. The operation of the embodiment of FIG. 2 will be described based on the flowchart.

When the program starts, the C / U 64 executes an initialization subroutine, turns off all outputs, and performs a clear check of the built-in RAM (not shown) (FIG. 4).
Step S1).

After performing the initialization, the above-mentioned switch 3
3, 45, 46, 50, 52, 53, 55, 58, 6
A subroutine for reading signals from the first, the second, the sixth, the sixth, and the 66 and the sensors 38 and 71 is executed (step S
2) Next, the processing subroutine of the rotation signal (pulse) read from the sensors 35, 36 and 40 is executed to calculate the engine speed, the input shaft speed and the vehicle speed, respectively (step S3).

The sensors 2, 34, 37, 39, 4
The analog signal processing subroutine read from 1, 47, 56, 59 and 69 is executed to execute digital values of engine load, clutch stroke, shift stroke, oil temperature, pressure, accelerator opening, brake depression amount and brake air pressure, respectively. (Step S4).

Reading and processing of these signals is performed once by C /
Update every U process. In addition, flags (not shown) used in the logic based on the read signal and the processed signal are set in these subroutines (excluding flags set / reset in the control history).

Subsequently, it is checked whether or not the key switch 66 is on (step S5), and when it is off, the all control stop subroutine is executed (step S6).

In this subroutine, even if the key switch 66 is turned off when the vehicle is stopped or running, all hydraulic systems are returned to a safe state in order to ensure safety, and then the actuator relay (not shown) is turned off in step S7. Then C / U6
The entire control is stopped by turning off the power supply of the control unit 4.

When the key switch 66 is turned on in step S5, it is checked whether or not the RBS main switch 53 is turned on (step S8). When it is turned off, a normal brake control mode subroutine described later is executed (same). When step S22) is on, it is determined that the driver is trying to perform a brake energy regeneration device (hereinafter, referred to as RBS) operation, and control is continued.

Therefore, the C / U 64 checks whether or not the driver operates the parking brake 51 (step S9), and when not operating (the parking brake switch 52a (P / B1) is off). At the time of)
The process proceeds to step S11 assuming that the RBS can be used, but when it is operated (when the parking brake switch 52a is on), the normal brake control mode (step S2) is performed.
Proceed to 2) to prohibit the use of RBS. This is to prevent the vehicle from jumping out even if the accelerator pedal 54 is inadvertently depressed while the parking brake lever 51 is being pulled.

However, in order to transmit the output torque of the pump / motor 14 to the wheels 11 while the parking brake is being operated when the vehicle starts on a slope or the like, it is checked whether or not another parking brake switch 52b is turned on (at the same step). S10).

Here, the parking brake switch 52
As shown in FIG. 12, b (P / B2) is turned on only when the knob 51a of the parking brake lever 51 is pushed. That is, since the state in which the knob 51a is pressed is when there is an intention to release the parking brake, the RBS can be used even when the parking brake lever 51 is pulled and the parking brake switch 52a is turned on. It is.

Next, the C / U 64 checks the selected gear by the gear position detection sensor 38 and the gear shift stroke sensor 39 (step S11),
If the gear is N (neutral) or R (reverse), the RBS is not used and the routine proceeds to the normal brake control mode subroutine (step S22), but the gear is 1st to 5th.
If the speed is high, the RBS is available and control is continued.

Then, it is checked whether or not the vehicle is stopped from the output of the vehicle speed sensor 40 (step S12), and if the vehicle is traveling, the process proceeds to step S14, where the current speed is below the permissible rotation speed of the pump / motor 14. Check if it corresponds. This allowable rotational speed is the gear ratio of the PTO device 8 and the axle 10 because the pump / motor 14 is connected to the wheel 11 via the electromagnetic clutch 13, the PTO shaft 12, the PTO device 8, the propeller shaft 9 and the axle 10. If it is constant, it can be judged by the vehicle speed, and if the allowable rotation speed of the commercially available pump / motor 14 is multiplied by the gear ratio and the wheel outer circumference, it can be conditioned that the RBS usable range is, for example, up to 50 km / h. .

In step S14, the vehicle speed is 50 km.
/ H or less, that is, if the pump / motor 14 is within the permissible rotational speed range, control is continued, but if it is determined that the permissible rotational speed range is exceeded, the normal brake control mode subroutine of step S22 is executed.

If the vehicle is a bus when the vehicle is stopped in step S12, a start prohibition subroutine is executed (step S13). This subroutine prohibits the use of the hydraulic circuit when the bus is opening the door, and when the door is open, it is assumed that passengers are getting on and off and it is not possible to ensure passenger safety. This is executed so that the vehicle does not start moving even if the accelerator is easily depressed.

Next, the C / U 64 checks the pedal operation of the driver in the order of brake (step S15) and accelerator (step S16) (each signal processing is completed by the analog signal processing subroutine of step S4). ). The reason why the check of the brake operation is prioritized over the check of the accelerator operation is that when the brake pedal 57 and the accelerator pedal 54 are simultaneously depressed, the brake is given priority on the safety side of the vehicle.

If the brake pedal 57 is depressed in step S15, the energy recovery mode subroutine shown in FIG. 5 is executed (step S17).

First, in step S171, the hydraulic brake torque is calculated based on the value Vp obtained by processing the output signal of the tilt angle sensor 80 in step S4 and the hydraulic circuit internal pressure P detected by the pressure sensor 47. The brake torque T _B0 generated by the motor 14 is obtained by the following equation. T _B0 = P · Vp / 200π (kgf · m) Equation (1)

The calculation of the required brake torque in step S172 is processing for appropriately distributing the value T _B obtained by processing the current output signal of the brake pedal depression amount sensor 59 in step S4 to the front and rear brakes. First,
According to the memory map of the brake pedal depression amount and the brake torque shown in FIG. 8 (also stored in the C / U 64), the required brake torque (kgf · m) is obtained from the output signal of the depression amount (angle) sensor 59 of the brake pedal 57. ).

That is, the brake depression amount sensor 5 attached to the brake pedal 57 uses the initial state of depression of the brake pedal 57 (for example, 0 to 3.5 °) as brake play.
9 is set to 0 by the brake pedal switch 58. When the brake pedal 57 exceeds the initial state (for example, 3.5 °), the sensor 59 outputs a voltage proportional to the pedal depression angle. Therefore, the brake pedal 57
Can be detected from the output of the sensor 59.

A section following the initial depression of the brake pedal 57 is a braking force control section (for example, 3.5 ° to 16 °), and the pump / motor 14 and the air brake device 72 are controlled in this section. Therefore, the required brake torque T _B corresponding to the depression angle of the brake pedal 57 is obtained from the map. However, at the beginning of this braking force control section
The partial section of 3.5 ° to 10 ° is C /
It is set to U64.

A section beyond the braking force control section (for example, 16 ° to 25 °) is during panic braking, and at this time, the electronic air pressure proportional control valve 70 is linked with the brake pedal 57 by a link mechanism (Fig. The brake air tank 68 and the brake force generator, for example, the air master 74 of the air-oil type, are forced to be pushed down by a force (not shown) to generate the maximum braking force by the compressed air. At this time, the use of the hydraulic circuit is prohibited because the vehicle may be in an unstable state.

Returning to step S172, after obtaining the required brake torque T _B as described above, the C / U 64 further searches the memory map (see FIG. 9) showing the axial load distribution to the front and rear shafts, for example. Front brake brake torque T
_BF , the rear brake brake torque T _BR is obtained. T _B = Brake torque by brake pedal depression amount sensor (kgf · m) T _BF = Brake torque required for front shaft (kgf · m) T _BR = Brake torque required for rear shaft (kgf · m) T _BO = Pump・ Brake torque generated by the motor (kgf · m) However, T _B = T _BF + T _BR .

The torque that can be generated by the hydraulic circuit in step S173 is calculated based on the brake torque T _B obtained by the brake pedal depression amount sensor, and the required displacement amount V
_{The PI} is determined, and the indicated capacity Vp for the pump / motor 14 is determined. V _PI = 200π · T _B / P (cc / rev) Equation (2)

However, since it is complicated to calculate this, a map of pressure, torque, and capacity as shown in FIG. 10 is created and stored in advance by this equation (2), and the map is needed from this map. It is possible to search for different capacity.

In this embodiment, as shown in FIG. 3, since the oblique shaft type axial piston type (or swash plate type axial piston type) pump / motor 14 can be used, its capacity V _P is It is controlled by controlling the tilt angle of the swash shaft (or the swash plate).

Furthermore, in step S174, the displacement capacity V _PI required now and the maximum rated capacity Vma of the pump / motor 14 are required.
x, and if V _PI > Vmax, the indicated capacity Vp =
Vmax is fixed to the maximum pump capacity (step S17).
5) If _VPI ≦ Vmax, the indicated capacity Vp = V
_PI is set (step S176).

Here, the above-mentioned insufficient braking torque
It is necessary to explain the search method using the memory map diagram in FIG.
Brake torque T_BPoint of hydraulic circuit pressure P corresponding to
Is on or below a straight line of the maximum capacity Vmax of the pump / motor 14.
If it is on the side, that is, in the shaded area in the figure, V_PI≤Vmax
Therefore, the required brake torque T is required only by the pump / motor 14. _B
Can be generated (for example, the required brake torque T_P),
Above the Vmax line (eg required brake
Torque T_A) Is V_PI> Vmax, pump / motor
14 required brake torque T_ACan occur
There will be no.

Therefore, in the case of V _PI > V max, the lacking brake torque, for example, T _A -T _P, is searched for, and this amount is replenished by the air brake or the air / oil brake. The electronic air pressure proportional control valve 70 is configured so that the air corresponding to the shortage of the generated brake torque is sent from the air tank 68 to the air master 74.
Will be driven.

Returning to FIG. 5, in step S177, it is determined whether or not the depression amount detected by the brake pedal depression amount sensor 59 is within the slow braking region shown in FIG. 8, but it is detected here. The required brake torque T _B corresponding to the depression amount is 10 °, which is the maximum depression amount in the slow braking area.
The required brake torque T _SB corresponding to

As a result, if T _B ≤T _SB , the amount of depression of the brake pedal is in the gentle braking region, so that the electronic brake proportional control valve 70 for the front wheels is operated to prevent the air brake device 72 from operating. Instructed torque for T _BAF = 0 (k
gf · m) (step S179), and the command torque T _BAR = 0 (kgf) to the electronic pneumatic proportional control valve 70 of the rear wheel.
.M) (step S180), step S1715
Proceed to.

If T _B > T _SB in step S177, it means that the braking area exceeds the gentle braking range. In this case, therefore, the braking torques T _B and T _BO are further compared (step S1).
78) As a result, if T _B ≦ T _BO , the air brake by the air brake device 72 is not necessary, so that the command torque T _BAF = to the electronic air pressure proportional control valve 70 of the front wheels is the same as in step S177. 0 (kgf · m) (step S178), and further, the instruction torque T _BAR = 0 (kgf · m) for the rear wheel electronic air pressure proportional control valve 70 is set (step S179), and the process proceeds to step S1715.

On the other hand, in step S178, T _B > T
If it is _BO , it is necessary to supplement the insufficient brake torque with the air brake by the air brake device 72 even if the pump / motor 14 is fixed to the maximum capacity, so this time compare the brake torques T _B0 and T _BR. (Step S171
0) and T _B0 > T _BR , the command torque T _BAF = T _B −T _BO (kgf ·
m) (step S1713), and apply the insufficient braking torque to the front wheels only by the air brake device 72,
The instruction torque T _BAR = 0 (kgf · m) to the electronic pneumatic proportional control valve 70 of the rear wheel is set (step S1714), and the air brake torque is not applied to the rear wheel. However,
The hydraulic brake torque from the pump / motor 14 is applied only to the rear wheels as usual.

Further, in step S1710, T _B0 ≤T _BR
If so, the command torque T _BAF = T _BF (kgf · m) for the electronic air pressure proportional control valve of the front wheels is set (step S171).
1) Apply the front-wheel-applied brake torque previously obtained as it is, and for the rear wheel, subtract the current hydraulic brake torque T _BO from the rear-wheel-applied brake torque T _BR and obtain the insufficient brake torque T _BR -T _The command torque T _BAR = T _BR −T _BO (kgf · m) for the electronic air pressure proportional control valve 70 that gives _BO to the rear wheels by the air brake device 72 (step S1712), and proceeds to step S1715. However, the hydraulic brake torque by the pump / motor 14 is applied only to the rear wheels in this case as well.

In step S1715, the instruction torque T determined in steps S178 to S1714 described above.
_BAF and T _BAR are applied to each electronic air pressure proportional control valve 70, and an air brake device 72 including a brake air tank 68 and an air master 74 connected thereto generates a braking force.

After executing the above subroutine, C
/ U64 returns to step S16 when it is found in step S15 of the main program that the brake pedal 57 is not depressed, and when the accelerator pedal 54 is depressed, the C / U 64 executes the energy regeneration mode subroutine. (A vehicle that travels by using the deceleration energy stored in the high-pressure accumulator 26 after being collected) is executed.

In this subroutine, the accelerator pedal 5
The required amount of torque is obtained by detecting the stepping amount of No. 4 for each gear,
The tilt angle (capacity) of the pump / motor 14 is determined based on this torque and the current pressure accumulation of the hydraulic circuit.

After executing the energy recovery mode subroutine and the energy regeneration mode subroutine in this way, the C / U 64 executes the normal brake control mode subroutine of step S22, which does not use hydraulic pressure but uses the air brake or the air In this mode, the brake is applied only with the oil brake.

This subroutine will be described with reference to FIG. 6. In step S221, the front brake brake torque T _BF and the rear brake brake torque T _BR are obtained from the same memory map as in step S172 (see FIG. 9), and the subsequent steps S222 and S223 are executed. In order to prevent the pump / motor 14 from braking, the instruction torque T to the electronic pneumatic proportional control valve 70 for each front wheel is set.
_BAF = brake torque T _BF required for the front shaft and command torque T _BAR for the electronic air pressure proportional control valve 70 for the rear wheels = brake torque T _BR required for the rear shaft.

Further, in step S224, the tilt angle is instructed to "0" (Vp = 0) as a countermeasure against the case where the hydraulic braking is being performed immediately before, and step S225 is performed.
Disconnect the hydraulic circuit connected to the PTO by
Return to the main program.

After the above control, the C / U 64 controls the oil amount (step S21 in FIG. 4). This oil amount control is a subroutine that determines whether oil supply is necessary or not based on whether the oil amount detection limit switch 45 is on or off and issues an operation request to the solenoid valves 31 and 32.

C / U64 is well known in Japanese Patent Laid-Open No. 60-117.
Similarly to the publication No. 69, a vehicle speed signal from the vehicle speed sensor 40, a signal corresponding to the depression amount of the accelerator pedal 54 from the accelerator opening detection sensor 56, and a select signal (matrix signal) from the gear select lever 60 are read, and the vehicle speed and FIG. 13 created according to the depression amount of the accelerator pedal 54
An appropriate T / M5 gear is selected based on the map shown in (steps S23 and S24 in FIG. 4).

In this operation, the clutch actuator 7 and the gear shift actuator 6 are driven so that the engine clutch (not shown) is disengaged, the gear of T / M5 is brought into a neutral state, selected and shifted, and the engine clutch is connected. By doing so, the gear stage of T / M5 is automatically shifted up / down to an appropriate gear stage according to the vehicle speed and the depression amount of the accelerator pedal 54.

Incidentally, the C / U 64 is based on the clutch control method determination subroutine shown in FIG. Since RBS = "1" (step S241 in FIG. 7), the engine clutch is disconnected (step S242). This flag F
L RBS is always in energy recovery mode,
In the energy regeneration mode, the flag is set when the vehicle travels only with the hydraulic pressure. RBS
If "0", a clutch connection control subroutine is executed (step S243).

Regarding the engagement / disengagement control of the engine clutch, an automatic clutch type automatic transmission vehicle is already known at present, and even if the vehicle does not have an automatic transmission, only the engine clutch is automatically operated. It suffices if connection / disconnection can be controlled. Further, in the case of a fluid type automatic transmission vehicle, the same effect can be obtained by controlling the gear to the neutral position for disconnection from the engine.

Subsequently, the capacity of the pump / motor 14, the disconnection / connection of the electromagnetic clutch 13, which is determined in the energy recovery mode, the regeneration mode, the normal brake control mode, etc.
According to the switching position of the circuit switching valve 25, a hydraulic circuit control subroutine for actually driving these is executed (step S25 in FIG. 4).

This hydraulic circuit control subroutine is a circuit switching valve 25, a pump / motor 14 and an electromagnetic clutch 1 which form a hydraulic circuit based on the above-mentioned various judgments / calculation results.
3 is for actually controlling.

After performing the hydraulic circuit control (step S25), the signals from the direct-coupled cooling relay switch 33 and the water temperature sensor 34 are read to stabilize the idle rotation during the warm-up operation of the engine 1 and during the cooling operation, as well as the replenishment. An idle control subroutine for stabilizing idle rotation when driving the pump 30 is executed (step S26).

After that, the target position of the step motor 3 is set by the output torque of the engine 1 determined in the above-mentioned energy regeneration mode or the like, and the engine control subroutine for driving this is executed (step S27). In this case, when the displacement V of the pump / motor 14 determined in the above-described energy regeneration mode or the like is V <250 cc, idling is performed. When V> 250 cc, the engine required output calculated from the following equation (3) is used. To control the engine so that it occurs. Engine required output = [(T / M required output)-(Pump motor maximum output) x (PTO gear ratio)] / (T / M gear ratio) Formula (3)

This engine output is obtained by converting the accelerator pedal depression amount as described above and then driving the fuel injection governor by the step motor.

After the above control and processing, an indicator control subroutine for displaying the hydraulic pressure and power source (hydraulic pressure, engine) and controlling the display of the indicators 63 is executed (step S28).

Then, on condition that the vehicle speed is "0" and the brake pedal 57 is stepped on, the electronic air pressure proportional control valve 70 is closed to keep the brake state, and the accelerator pedal 54 is stepped on, or When the gear select lever 60 is in the neutral position, the HSA control subroutine for releasing the braking state is executed (step S29).

After that, it is checked whether or not it is time to execute the self-diagnosis (step S30 in the same step), and when the time is reached, the self-diagnosis is executed periodically (for example, 500 ms) (step S31 in the same step), and the process is executed. After waiting for the time to make the time constant (step S32), the process returns to step S2 and the above-described processing is repeated.

The above subroutine (step S23
31) can use the technology already known at present.

[0082]

As described above, according to the brake energy regeneration device for a vehicle according to the present invention, when the amount of depression of the brake pedal is in the slow braking region of a predetermined value or less,
When the brake torque is generated only by the hydraulic circuit by controlling the motor and the brake pedal depression amount exceeds a predetermined value, the front and rear wheels determine the required brake torque corresponding to the detected brake pedal depression amount by the axle weight. The brake torque to be borne is determined in advance according to a predetermined distribution ratio of the above, and when the current hydraulic brake torque currently generated by the pump / motor exceeds the brake torque borne by the rear wheels, the insufficient brake torque is supplied to the air pressure. When the current hydraulic brake torque is applied to the front wheels by a brake device and the current hydraulic brake torque is equal to or less than the rear wheel burden brake torque, only the front wheel burden brake torque is generated by the air brake device and applied to the front wheels, and the rear wheel burden brake torque is applied to the current hydraulic pressure. Insufficient brake torque obtained by subtracting the brake torque is applied to the rear wheels by the air brake device. Since it is configured to give the vehicle, by improving the responsiveness of the entire braking device that combines the hydraulic regenerative brake and the air brake, and by optimally distributing the braking force of the front and rear wheels when a large braking force is generated, It is possible to ensure stability.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a vehicle brake energy regeneration device according to the present invention.

FIG. 2 is a diagram showing a configuration of an embodiment of a vehicle brake energy regeneration device according to the present invention.

FIG. 3 is a cross-sectional view and a perspective view, respectively, of a diagonal axial piston pump / motor used in the present invention.

FIG. 4 is a flowchart of a program stored and executed by a control unit of the present invention.

FIG. 5 is a flow chart diagram of an energy recovery mode subroutine according to the present invention.

FIG. 6 is a flowchart of a normal brake control mode subroutine.

FIG. 7 is a flowchart of a clutch control method determination subroutine.

FIG. 8 is a brake torque map of a brake pedal depression amount versus a brake torque.

FIG. 9 is an ideal distribution map of front and rear wheels of brake torque.

FIG. 10 is a brake torque map diagram of the pressure in the hydraulic circuit versus the required brake torque with the pump / motor capacity as a parameter.

FIG. 11 is a diagram showing a brake torque region that can be generated by a pump / motor in a brake torque map of pressure in a hydraulic circuit versus required brake torque.

FIG. 12 is a schematic structural view for explaining a parking brake lever.

FIG. 13 is a gear shift map diagram based on a vehicle speed and an accelerator pedal depression amount.

[Explanation of symbols]

Reference Signs List 1 engine 5 T / M (transmission) 8 PTO device 13 electromagnetic clutch 14 pump / motor 25 circuit cut-off (switching) valve 26 high-pressure accumulator 27 low-pressure accumulator 47 pressure sensor 57 brake pedal 59 brake depression amount sensor 64 C as control means / U 67 Brake air piping 70 Electronic air pressure proportional control valve or electromagnetic proportional pressure control valve 72 Air brake device In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

(57) [Claims] 1. A hydraulic circuit, a brake pedal depression amount detecting means, an air pressure proportional control valve, an air brake device, and a necessary brake torque detected by the detecting means is generated by a pump / motor of the hydraulic circuit. Control means for maximizing the pump capacity of the pump / motor and supplementing the insufficient brake torque with the air brake device by controlling the proportional control valve when the current hydraulic brake torque is exceeded. In the vehicle brake energy regeneration device provided, the control means controls the pump / motor to generate a brake torque only by the hydraulic circuit while the brake pedal depression amount is in a slow braking region of a predetermined value or less. , When the amount of depression of the brake pedal exceeds a predetermined value, the required brake torque is determined by the axle load and a predetermined distribution ratio of front wheels and rear wheels is obtained. Therefore, the brake torque to be borne is determined, and when the present hydraulic brake torque exceeds the borne brake torque of the rear wheels, the deficient brake torque is applied to the front wheels by the air brake device to obtain the present hydraulic brake torque. Is equal to or less than the rear wheel burden brake torque, only the front wheel burden brake torque is generated by the air brake device and applied to the front wheels, and a shortage brake torque obtained by subtracting the current hydraulic brake torque from the rear wheel burden brake torque is applied. A braking energy regeneration device for a vehicle, characterized in that the air braking device is applied to the rear wheels. 2. A brake energy regenerating apparatus for a vehicle according to claim 1, wherein all of said hydraulic brake torque is applied to rear wheels.