JP2505966Y2 - Break energy regeneration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a brake energy regenerator that recovers deceleration energy during vehicle deceleration, and more particularly to a flow rate control technique for a pump motor when the regenerator is operating.

<Prior Art> Conventionally, as this type of brake energy regeneration device,
For example, there is one disclosed in JP-A-62-31522.

In this type, a pump motor is connected to a wheel drive system via an electromagnetic clutch, one port of the pump motor is connected to an accumulator via a high pressure oil passage, and the other port is connected to an oil via a low pressure oil passage. It is connected to the tank. When the vehicle is decelerated, the pump motor is connected to the wheel drive system to operate as a pump, so that the wheel drive system is braked by using the pump motor as a load and high pressure oil is accumulated in the accumulator to recover deceleration energy. Has been done.

Here, the braking torque (accumulated energy) in the regenerative device is controlled by controlling the tilt angle of the swash plate of the pump motor to control the flow rate of the pump motor.

The accumulated deceleration energy is used as drive energy for the wheel drive system by being connected to the pump motor wheel drive system to act as a motor when the vehicle starts, for example.

<Problems to be Solved by the Invention> By the way, in such a conventional device, the tilt angle of the swash plate of the pump motor is controlled based on the depression amount of the brake pedal. When accumulating hydraulic energy in the accumulator during braking, the system capacity (pump capacity, etc.) is small and the amount of energy recovered per unit time is limited, so that as much energy as possible can be recovered as soon as possible. The flow rate of the pump motor is controlled between 0 and 30% of the total depression amount, and the pump motor capacity becomes constant at the maximum when the amount exceeds 30%. For this reason,
When the maximum value of the generated braking force is the same as that of the normal foot brake, a braking force larger than that of the normal foot brake is generated with respect to the change rate of the brake pedal depression amount.
Therefore, by reacting more sensitively to the pedal depression amount than the normal foot brake, the driver may feel uncomfortable unlike the braking feeling of the normal foot brake.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a brake energy regeneration device that reacts with a feeling substantially similar to that of a normal foot brake.

<Means for Solving the Problems> Therefore, according to the present invention, when the vehicle is decelerated, the pump motor is connected to the vehicle wheel drive system to operate as a pump, and the oil in the low pressure side accumulator is pumped into the high pressure side accumulator. In the brake energy regeneration device configured to recover the brake energy by accumulating the pressure, a brake working fluid circuit that generates a brake working fluid pressure by operating a brake pedal is provided with a fluid pressure detecting means for detecting the fluid pressure, Control means is provided for controlling the tilt angle of the swash plate for flow rate control of the pump motor based on the fluid pressure detected by the detection means.

<Operation> According to the above configuration, the fluid pressure detecting means detects the fluid pressure generated in the brake working fluid circuit by depressing the brake pedal. The tilt angle of the swash plate of the pump motor is controlled based on the detected fluid pressure to control the flow rate of the pump motor. Since the fluid pressure is generated in accordance with the brake pedal depression amount in a normal foot brake (corresponding to the braking force required by the driver), if the flow rate of the pump motor is controlled based on the fluid pressure, the regenerative device can operate. The generated braking force can be matched with the braking force required by the driver, and the same feeling as a normal foot brake can be obtained.

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings.

Referring to FIG. 1 showing the configuration of the first embodiment of the present invention, an output shaft of an engine body 1 includes an engine clutch 2, a transmission 3, a propeller shaft 4 and a final reduction gear device 5.
It is connected to the wheel 6 via. A pump motor 8 is connected to the final speed reducer 5 via an electromagnetic clutch 7.
The first solenoid valve 9 is provided at one port of the pump motor 8.
Low pressure side accumulator via low pressure oil passage 10
11 is connected to the other port, and a high pressure side accumulator 14 is connected to the other port via a high pressure oil passage 13 in which a second electromagnetic valve 12 is interposed. Further, the high pressure oil passage 13 and the low pressure oil passage 10 are configured to be connectable by bypassing the pump motor 8 by the third solenoid valve 15.

On the other hand, when the brake pedal 17 is depressed, the brake valve 16 controls the air pressure from the air reservoir 18 in accordance with the depression angle or the like, and supplies the air pressure according to the depression angle or the like via the fourth solenoid valve 28. The pressure is supplied as an instruction pressure to the relay valve 21 of the air booster 20 through the mounted air passage 19. The relay valve 21 supplies air of the same pressure as the indicated pressure from the air reservoir 18 to the air booster 20 to generate hydraulic pressure, supplies hydraulic pressure to each wheel cylinder 23 via the hydraulic passage 22, and spreads the brake shoe 24. To generate braking force. Further, the air passage 19 is provided with a pressure sensor 25 as a fluid pressure detecting means for detecting the generated air pressure.

A pressure signal from the pressure sensor 25 is input to a control unit 26 including a microcomputer or the like. In the control unit 26, the relationship between the air pressure and the control current for driving and controlling the flow rate control swash plate of the pump motor 8 is stored as a map. Then, the control current value corresponding to the input air pressure signal is retrieved from the map, the corresponding control current value is output to the swash plate drive device 27 to control the tilt angle of the swash plate, and the request from the driver is given. The control is performed so that the flow rate of the pump motor 8 corresponding to the braking torque being applied is obtained. Here, the control unit 26 corresponds to a control means.

Next, the brake energy regeneration operation by the control unit 26 of the present embodiment will be described with reference to the flowchart of FIG.

First, step (indicated by S in the figure, the same applies hereinafter) 1
Then, the air pressure P in the air passage 19 is input by the pressure sensor 25.

In step 2, it is determined based on the presence or absence of the air pressure P whether or not the driver has performed a brake operation (presence or absence of a brake request). When the determination in step 2 is YES, the process proceeds to step 3.

In step 3, it is determined whether or not the brake energy regeneration operation is performed. This determination is made based on whether or not the braking energy can be effectively regenerated based on the vehicle speed at that time, the current pressure of the accumulators 11 and 14, and the like. If the determination is YES, go to step 4.

In step 4, the first to fourth solenoid valves 9, 12, 15, 28 are drive-controlled. That is, the first solenoid valve 9 and the second solenoid valve 12 which are respectively inserted in the low pressure oil passage 10 and the high pressure oil passage 13 are opened, the third solenoid valve 15 bypassing the pump motor 8 is closed, and the air passage 19 is closed. The interposed fourth solenoid valve 28 is closed.

In step 5, the electromagnetic clutch 7 is connected and controlled to connect the pump motor 8 to the wheel drive system.

In step 6, from the map showing the relationship between the air pressure P stored in advance and the control current value I of the swash plate of the pump motor 8, the air pressure P of the air passage 19 inputted from the pressure sensor 25 is inputted.
The control current value I corresponding to is searched.

In step 7, the retrieved control current value I is output to the swash plate drive device 27.

If the determination in step 3 is NO, the process proceeds to step 8 and the wheel drive system is not connected to the pump motor 8
The solenoid valve 28 is opened to perform a normal foot brake operation.

With such a configuration, the load of the pump motor 8 can be set according to the braking force required by the driver, and the same feeling as that of a normal foot brake can be obtained.

In the above embodiment, the air pressure blown out from the brake valve 16 is detected, but as shown by the broken line in FIG. 1, the oil pressure supplied from the air booster 20 to the wheel cylinder 23 is detected. If so, a feeling similar to that of the foot brake can be obtained more accurately.

In the first embodiment described above, the one applied to the air over hydraulic brake is shown, but the present invention is not limited to this, and as shown in FIG. 3, instead of the brake valve 16, a hydraulic pressure corresponding to the depression amount of the brake pedal is applied. It can also be applied to an oil brake using the generated master cylinder 31.

Further, the air pressure from the brake valve 16 as shown in FIG. 4 is passed through the quick release valve 32 to the air chamber.
It can also be applied to an air brake designed to supply to 33.

In any of the second and third embodiments, the detected brake working fluid pressure for swash plate tilt angle control is the discharge pressure from the master cylinder 31, the brake valve 16, the air booster 20, or the quick release valve. Either discharge pressure from 32 may be used. However, in any of the first to third embodiments, when the pressure on the downstream side is used as the detection brake working fluid pressure for the swash plate tilt angle control, the fourth solenoid valve is provided on the downstream side of the detection portion. 28 must be inserted.

Further, the pump motor and the wheel drive system may be connected to the transmission side.

<Effect of the Invention> As described above, according to the present invention, the brake working fluid pressure generated in response to the operation of the brake pedal is detected, and the swash plate tilt angle of the pump motor is controlled according to the detected value. Since the configuration is adopted, it is possible to obtain the same feeling of braking as a normal foot brake even with the brake energy regeneration device, and it is possible to eliminate the driver's discomfort.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention, FIG. 2 is a control flowchart of the first embodiment of the same as above, and FIGS. 3 and 4 show second and third embodiments of the present invention, respectively. It is a block diagram. 1 ... Engine body, 2 ... Engine clutch, 3 ...
Transmission, 4 …… propeller shaft, 5 ……
Final reducer, 6 ... Wheels, 7 ... Electromagnetic clutch, 8 ... Pump motor, 9 ... First solenoid valve, 10 ... Low-pressure oil passage, 11 ...
… Low pressure side accumulator, 12 …… Second solenoid valve, 13 …… High pressure oil passage, 14 …… High pressure side accumulator, 19 …… Air passage, 23 …… Wheel cylinder, 25 …… Pressure sensor, 26…
… Control unit, 27… Swash plate drive

Claims (1)

(57) [Scope of utility model registration request] 1. A brake motor is connected to a wheel drive system of a vehicle when the vehicle is decelerated to operate as a pump, and the oil in the low-pressure side accumulator is pumped into the high-pressure side accumulator to accumulate pressure, thereby recovering brake energy. In the brake energy regeneration device having the configuration, a brake working fluid circuit for generating a brake working fluid pressure by operating a brake pedal is provided with fluid pressure detecting means for detecting the fluid pressure, and the fluid pressure detecting means detects the fluid pressure based on the fluid pressure detected by the detecting means. A brake energy regeneration device comprising control means for controlling a tilt angle of a swash plate for controlling a flow rate of a pump motor.