JPH05112225A - Brake energy generating device of car - Google Patents

Abstract

PURPOSE:To produce necessary braking force by generating only the brake torque shared by the front wheels from an air brake device, applying it to the front wheels, and giving the rear wheels from air brake device a brake torque in an amount corresponding to the lack determined by subtracting the current hydraulic brake torque from the brake torque shared by the rear wheels. CONSTITUTION:When the current hydraulic brake torque goes under the requisite brake torque and is below the brake torque shared by the rear wheels, only the brake torque shared by the front wheels is produced by an air brake device 72 by operating an air pressire proportional control valve 70 and applied to the front wheels, while the current hydraulic brake torque is all given to the rear wheels. The brake torque in an amount corresponding to the lack at this time (obtained by subtracting the current hydraulic brake torque from the brake torque shared by the rear wheels) is produced by the air brake device 72 by operating the control valve 70 and is applied to the rear wheels.

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 regeneration device for recovering deceleration energy of a vehicle and utilizing it as start / acceleration energy.

[0002]

2. Description of the Related Art Of the kinetic energy lost during deceleration of a vehicle, the amount mainly dissipated as heat (brake, 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 that uses this accumulated energy as starting energy and acceleration energy for the vehicle or an axle equipped with a transfer has been known for a long time. In the early 1970s, German M. A. N. Since various researches and developments have been made in Europe and the United States, such as the start of researches, etc., the research and development by the present inventor is also Japanese Patent Application No. 63-27275.
No. 0 etc.

In the vehicle brake energy regenerating apparatus disclosed in Japanese Patent Application No. 63-272750 by the inventor of the present invention, electromagnetic proportional air pressure control is performed when the required regenerative brake alone cannot cover all the required braking torque. The valve is used to control the shortage of brake torque with the air brake.

This is to eliminate the driver's discomfort with respect to the brake by keeping the relationship between the brake pedal depression amount and the brake torque to be generated constant.

That is, the pump capacity required for the pump / motor is obtained from the required brake torque determined by the stepping amount 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. If so, the pump capacity of the pump / motor is maximized, and the insufficient braking force is controlled by the air brake device by 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 in some cases it is necessary to further depress the brake pedal.

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. It is an object of the present invention to provide a braking energy regeneration device for a vehicle, which is provided with the above-mentioned means, and can always generate a necessary braking force with a response equal to or higher than that of a normal air braking device.

[0008]

In order to achieve the above object, in a vehicle brake energy regenerating apparatus according to the present invention, the control means has a predetermined distribution ratio of front wheels and rear wheels which determines the required brake torque by the axial load. The braking torque to be borne according to the present invention is determined in advance, and when the present hydraulic braking torque exceeds the braking torque borne by the rear wheels, all the present hydraulic braking torque is applied to the rear wheels and the insufficient braking torque is applied to the air. 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 current hydraulic brake torque is applied to the rear wheels. A shortage of the braking torque, which is obtained by subtracting the current hydraulic braking torque from the braking torque applied to the rear wheels, It is obtained as applied to the rear wheel by A brake device.

[0009]

The present invention will be described with reference to the schematic view of FIG. 1. The control means (C / U) 64 is composed of a hydraulic circuit (high pressure accumulator 26, circuit valve 25, pump / motor 14, low pressure accumulator 27). The present hydraulic brake torque by the hydraulic circuit is obtained from the pump capacity of the pump motor 14 when the brake motor 14 is braked, and the necessary brake torque is obtained from, for example, the brake pedal depression amount sensor 59 as the brake pedal depression amount detecting means. Then, the required braking torque thus determined is determined in advance according to a predetermined distribution ratio of the front wheels and the rear wheels determined by the axial load.

Then, when the required brake torque is equal to or less than the current hydraulic brake torque, the control means 64 uses only the hydraulic brake torque corresponding to the pump motor 14 to adjust the pump capacity to the required brake torque of the vehicle as usual. Hang on the rear wheel.

When the required brake torque exceeds the current hydraulic brake torque, the pump / motor 14 is controlled to fix the pump displacement to the maximum, and the current hydraulic brake torque is further reduced to the rear wheel-borne 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. It is generated and given to the front wheels.

On the other hand, when the current hydraulic brake torque is lower than the required brake torque and is equal to or less than the rear wheel-bearing brake torque, the air-pressure proportional control valve 70 is controlled by controlling only the front-wheel-bearing brake torque to the air brake device 72.
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 burden 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, the insufficient braking torque when the required braking torque at the time of braking is large is variably controlled between the regenerative braking by hydraulic pressure and the air brakes for the front wheels and the rear wheels, so that the regenerative braking and the air brake are controlled. It is possible to secure the responsiveness of the overall braking device and the vehicle stability by optimally distributing the braking force of the front wheels and the rear wheels when a large braking force is generated.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a vehicle brake energy regeneration device 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 for automatically shifting the gear stage (not shown) of T / M 5, 7 is a clutch actuator for automatically connecting and disconnecting a clutch (not shown), and 8 is T / M
5, a PTO device engaged with 5, a propeller shaft 9 forming a drive system for the wheel together with an axle 10 and wheels 11, 12 a PTO shaft of PTO device 8, 13 an electromagnetic clutch, 14 a PTO shaft 12 and an electromagnetic clutch A well-known variable displacement oblique shaft type axially engaged with the PTO device 8 via 13 and combined with a tilt angle control pilot pipe 15, a tilt angle control electromagnetic proportional control valve 16 and a tilt angle control piston 17. It is a piston pump motor, 14a is its suction port, and 14b is its discharge port. Also, 80 is a pump
The tilt angle sensor detects a tilt angle of the motor 14.

Here, the pump / motor 14 is shown in FIG.
Referring to (a) and FIG. 3 (b) which is a view from the arrow A 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. In addition, around the cylinder block 14f,
A plurality of cylinders 14g are provided, a piston 14e engaged with the output shaft 14c is slidably inserted into one end of the cylinder 14g, and the other side thereof is shown in FIG. (4) 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 pipe 20 or 21. Therefore, the cylinder block 14f and 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 referred to as a tilt angle.

FIG. 1A shows a tilt angle control solenoid proportional control valve 16
When the maximum control current is applied to the output shaft 14c and the tilt angle is maximum, the discharge amount per one rotation of the output shaft 14c is 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.
Therefore, the discharge amount becomes "0".

Returning to FIG. 2, reference numeral 18 is 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 supply pressure of hydraulic oil in 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 tilting the pump / motor 14 in the tilt angle control pilot pipe 15, 20 is a suction side pipe of the pump / motor 14, 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 that switches the above 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 The pump / motor 14 and the circuit switching valve 2 are connected to the circuit switching valve 25 via the side pipe 24.
5 and a high pressure accumulator 26, which is a low pressure accumulator forming a hydraulic circuit.

The circuit switching valve 25 is used for the pump / motor 1
When the inlet / outlet of 4 is fixed and used, it is necessary to switch the output during pumping and motoring. If a reversing piston pump / motor is used for the pump / motor 14, a circuit shutoff valve is used. You can also These circuit switching valve and circuit shutoff valve can be collectively referred to as a circuit valve.

The switching operation of the piping by the circuit switching valve 25 will be described below. The electromagnets 25a and 25b thereof will be described.
When none of these is energized, the valve position becomes the position shown in the center of the three valve positions, and the four pipes 20, 21, 2
3 and 24 connections are broken.

When recovering the braking energy,
The electromagnet 25a is energized to switch the valve position to the electromagnet 25a side. 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 driven by the brake energy and sucked / in by the pump / motor 14 that functions as a pump.
It is discharged and pressure is accumulated in the high pressure accumulator 26.

On the contrary, when the pump / motor 14 is to function 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 14b of the pump / motor 14 via the pipes 24 and 21, and the high-pressure accumulator 26 can be connected to the suction port 14a of the pump / motor 14 via the pipes 23 and 20. As a result, the hydraulic oil stored 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 drain tank for hydraulic oil, 29 is a filter for hydraulic oil, 30 is a replenishing pump for hydraulic oil driven by the engine 1, 31 and 32 are provided on the replenishing pipe 22, and are connected 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 for supplying pilot hydraulic pressure to the 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).
A cylinder for driving the cylinder, 44 is an air pipe for supplying air pressure to the cylinder 43 via the exhaust brake control valve 42, 45
Reference numerals 46 and 46 are oil amount detection limit switches provided in the drain tank 28, and 47 is 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 pedal amount sensor, 60 is a gear select lever, and 61 is a slope. Starting assistance device (hereinafter,
HSA), 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 the pump based on the outputs of the above sensors and switches.
A control unit (hereinafter, abbreviated as C / U) is a control unit that controls the motor 14 and the actuator to regenerate the braking energy. It should be noted that the brake air tank 68 and the air master 74 make the air brake device 7
In addition, 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 flow chart diagram of a program stored and executed in FIG. 2, and the operation of the embodiment of FIG. 2 will be described based on this flow chart.

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 sensors 1, 62, 65, 66 and the sensors 38, 71 is executed (at the step S
2) Next, the processing subroutine of the rotation signals (pulses) 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).

Then, the sensors 2, 34, 37, 39, 4
The analog signal processing subroutines read from Nos. 1, 47, 56, 59, and 69 are executed to execute digital engine load, clutch stroke, shift stroke, oil temperature, pressure, accelerator opening, brake depression amount, and brake air pressure, respectively. Is calculated (step S4).

Reading and processing of these signals is performed once by C /
Update every U process. In addition, a flag (not shown) used in the logic according to the read signal and the processed signal is set in these subroutines (except the flag set / reset in the control history).

Then, 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, the hydraulic system is 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
All the controls are stopped by turning off the power supply of No. 4.

When the key switch 66 is on in step S5, it is checked whether or not the RBS main switch 53 is on (step S8), and when it is 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 is operating the parking brake 51 (step S9), and when not operating (parking brake switch 52a (P / B1) is off). At the time of)
Although it is determined that the RBS can be used, the process proceeds to step S11. However, when the RBS 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, such as when starting on a slope, 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 pushed is when there is an intention to release the parking brake, the RBS can be used even if the parking brake lever 51 is pulled and the parking brake switch 52a is on. 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), 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 from the output of the vehicle speed sensor 40 whether or not the vehicle is stopped (step S12). If the vehicle is traveling, the process proceeds to step S14, where the current speed is below the permissible rotational 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 determined 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 outer circumference of the wheel, it can be conditioned that the RBS usable range is up to 50 km / h, for example. ..

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, the control is continued. However, if it is determined that the permissible rotational speed range is exceeded, the normal brake control mode subroutine of step S22 (described later) is executed. Run.

If the vehicle is a bus when the vehicle is stopped in step S12, a start prohibiting subroutine is executed (step S13). This subroutine prohibits the use of the hydraulic circuit when the bus is open, and when the door is open, it is considered that passengers are getting on and off, and it is not possible to ensure passenger safety. This is executed in order to prevent the vehicle from moving even if the accelerator is easily stepped on.

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 stepped on at the same time, the brake is prioritized as 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, the calculation of the hydraulic brake torque in step S171 is performed 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 a process 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 (which is 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 initial state of depression of the brake pedal 57 (for example, 0 to 3.5 °) is used as brake play, and the brake depression amount sensor 5 attached to the brake pedal 57 is used.
The output voltage of 9 is set to 0 by the brake pedal switch 58. When the initial state of depression of the brake pedal 57 (for example, 3.5 °) is exceeded, the sensor 59 outputs a voltage proportional to the pedal depression angle. Therefore, the brake pedal 57
The stepping angle of 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.

The section exceeding the braking force control section (for example, 16 ° to 25 °) is during panic braking,
At this time, the electronic air pressure proportional control valve 70 is forcibly pushed down by the link mechanism (not shown) communicating with the brake pedal 57, and the brake air tank 68 and the brake force generator, for example, the air in the air-oil type, The maximum braking force by the compressed air is generated by making the master 74 and all the same. At this time, use of the hydraulic circuit is prohibited because the vehicle may become unstable.

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 for the front and rear shafts, for example. Front brake brake torque T
_BF , rear brake _Calculate brake torque T _BR . T _B = Brake torque from brake pedal depression sensor (kgf ・ m) T _BF = Brake torque required for front axle (kgf ・ m) T _BR = Brake torque required for rear axle (kgf ・ m) T _BO = Pump・ Brake torque generated by the motor (kgf ・ m) However, T _B = T _BF + T _BR .

Then, the torque calculation that can be generated in the hydraulic circuit in step S173 is based on the brake torque T _B by the brake pedal depression amount sensor, and the required displacement amount V is now required.
_{The PI} is determined and the instructed 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.

[0052] In this embodiment, bent axis type axial piston type as shown in FIG. 3 (or, the swash plate type may be axial piston type) because it is possible to use a pump motor 14, the volume V _P is It is controlled by controlling the tilt angle of the swash shaft (or the swash plate).

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

Here, the search method of the above-mentioned insufficient brake torque will be described with reference to the memory map diagram of FIG. 11. The point of the hydraulic circuit pressure P corresponding to the required brake torque T _B is the maximum of the pump / motor 14. When it is on the straight line or below the capacity Vmax, that is, in the shaded area in the figure, V _PI ≦ Vmax, so the pump / motor 14 alone requires the required braking torque T _B.
Can be generated (for example, required braking torque T _P ),
When it is above the line of Vmax (for example, required brake torque T _A ), V _PI > Vmax, and the pump / motor 14 cannot generate the required brake torque T _A.

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 provided 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, the brake torques T _B and T _BO are compared, and as a result, T _B ≤
If it is T _BO , the air brake by the air brake device 72 is not necessary, so the command torque T _BAF = 0 (kgf · m) to the electronic pneumatic proportional control valve 70 of the front wheel is set (step S
178), and further, as an instruction torque T _BAR = 0 (kgf · m) to the electronic pneumatic proportional control valve 70 of the rear wheel (step S
179) and the process proceeds to step S1715.

If T _B > T _BO in step S177, 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. The torques T _B0 and T _BR are compared (step S1710), and T _B0
If> T _BR , the command torque T _BAF = T _B −T _BO (kgf · m) to the electronic pneumatic proportional control valve 70 for the front wheels is set (step S1713), and the insufficient braking torque is set to the air brake device 72. Therefore, the instruction torque T _BAR = 0 for the electronic air pressure proportional control valve 70 of the rear wheel
As (kgf · m) (step S1714), no brake torque is applied to the rear wheels. However, the hydraulic brake torque by the pump / motor 14 is applied only to the rear wheels as usual.

In step S1710, T _B0 ≤T _BR
If so, the instruction torque T _BAF = T _BF (kgf · m) for the electronic pneumatic proportional control valve for the front wheels is set (step S171).
1), prior to it over the front wheel brake torque burden that has been asked, shortage of the brake torque T _BR -T minus the current hydraulic brake torque T _BO for the rear wheels further from the rear wheel burden brake torque T _{BR BO} is used as the instruction torque T _BAR = T _BR −T _BO (kgf · m) for the electronic air pressure proportional control valve 70 to be applied to the rear wheels by the air brake device 72 (step S1712), and the process proceeds to step S1715. However, also in this case, the hydraulic brake torque by the pump / motor 14 is applied only to the rear wheels.

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 determined in step S15 of the main program that the brake pedal 57 has not been depressed, and when the accelerator pedal 54 is depressed, the C / U 64 indicates that the energy regeneration mode subroutine (The vehicle that travels by utilizing the deceleration energy that is collected and accumulated in the high-pressure accumulator 26) is executed.

In this subroutine, the accelerator pedal 5
The required amount of torque is calculated by detecting the stepping amount of 4 for each gear
The tilt angle (capacity) of the pump / motor 14 is determined by this torque and the current accumulated pressure in the hydraulic circuit.

After executing the energy recovery mode subroutine and the energy regeneration mode subroutine in this manner, 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 brake. In this mode, the brakes are 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 (see FIG. 9) as in step S172, and the subsequent steps S222 and S223 are performed. In order to prevent the braking by the pump / motor 14, the command torque T for the electronic pneumatic proportional control valve 70 for each front wheel is set.
_BAF = brake torque T _BF required for the front axle and command torque T _BAR for the rear wheel electronic air pressure proportional control valve 70 = brake torque T _BR required for the rear axle.

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 until immediately before, and in step S225.
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 or not oil supply is necessary depending 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 Publication No. 60-117.
Similarly to Japanese Patent No. 69, the vehicle speed signal from the vehicle speed sensor 40, the signal corresponding to the depression amount of the accelerator pedal 54 from the accelerator opening detection sensor 56, and the select signal (matrix signal) from the gear select lever 60 are read to read 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 (4) (steps S23 and S24 in FIG. 4).

In this operation, the clutch actuator 7 and the gear shift actuator 6 are driven, and the engine clutch (not shown) is disengaged → T / M5 gear is set to the neutral state → Select and shift → Connect the engine clutch. By doing so, the gear stage of T / M5 is automatically shifted up / down to an appropriate one 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 is "1" (step S241 in FIG. 7), the engine clutch is disengaged (step S242). This flag F
L When the RBS is in energy recovery mode,
Also, in the energy regeneration mode, it is set when traveling only with hydraulic pressure, and the flag FL RBS
When = "0", the 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 automatic transmission vehicle, the same effect can be obtained by disconnecting the engine from the engine by controlling the gear to the neutral position.

Subsequently, the capacity of the pump / motor 14, the disconnection / contact 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 connection 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, 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 capacity V of the pump / motor 14 determined in the above-mentioned energy regeneration mode is V <250 cc, idling is performed, and when V> 250 cc, the engine required output obtained from the following equation (3) The engine is controlled so that Engine required output = [(T / M required output)-(Pump motor maximum output) x (PTO gear ratio)] / (T / M gear ratio) Formula (3)

The engine output is obtained by converting the depression amount of the accelerator pedal 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 depressed, the electronic air pressure proportional control valve 70 is closed to keep the brake state, and the accelerator pedal 54 is depressed, 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 self-diagnosis (step S30), and when it is time, self-diagnosis is executed periodically (for example, 500 ms) (step S31), and the process is executed. After waiting for a time to make the time constant (at 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.

[0079]

As described above, according to the vehicle brake energy regenerating apparatus of the present invention, the required brake torque corresponding to the detected brake pedal depression amount is determined by the axial load and the predetermined distribution ratio of the front wheels and the rear wheels is obtained. When the current hydraulic brake torque currently generated by the pump / motor exceeds the brake torque applied to the rear wheels, the insufficient brake torque is applied to the front wheels by the air brake device. When the current hydraulic brake torque is less than or equal to 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 current hydraulic brake torque is subtracted from the rear wheel burden brake torque. Since the shortage of braking torque is applied to the rear wheels by the air brake device, It is possible to improve the responsiveness of the entire braking system that combines the hydraulic regenerative brake and the air brake, and ensure vehicle stability by optimally distributing the braking force of the front and rear wheels when a large braking force is generated. it can.

[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.

3A and 3B are a cross-sectional view and a perspective view, respectively, of an oblique shaft type axial piston pump / motor used in the present invention.

FIG. 4 is a flow chart diagram of a program stored and executed by the control means of the present invention.

FIG. 5 is a flowchart 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 diagram of brake pedal depression amount vs. brake torque.

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

FIG. 10 is a brake torque map diagram of hydraulic circuit pressure vs. required brake torque with 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 diagram 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]

1 Engine 5 T / M (Transmission) 8 PTO Device 13 Electromagnetic Clutch 14 Pump / Motor 25 Circuit Cutoff (Switch) Valve 26 High Pressure Accumulator 27 Low Pressure Accumulator 47 Pressure Sensor 57 Brake Pedal 59 Brake Depth Sensor 64 Control C / 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)

[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 a vehicle brake energy regeneration device provided with the control means, the required braking torque is determined in advance according to a predetermined distribution ratio of front wheels and rear wheels that is determined by the axial load, and the present hydraulic brake torque is determined. When the rear wheel burden brake torque is exceeded, the insufficient brake torque is applied to the front wheels by the air brake device, When the current hydraulic brake torque is less than or equal to the rear wheel-borne brake torque, only the front wheel-borne brake torque is generated by the air brake device and applied to the front wheels, and the shortage resulting from subtracting the current hydraulic brake torque from the rear-wheel-borne brake torque. A braking energy regeneration device for a vehicle, characterized in that the brake torque is applied to the rear wheels by the air brake device. 2. The brake energy regenerating apparatus for a vehicle according to claim 1, wherein all of the hydraulic brake torque is applied to the rear wheels.