JPH0723063B2 - Vehicle brake energy regeneration device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a braking energy regeneration device for a vehicle that recovers deceleration energy of the vehicle and uses it as start / acceleration energy.

[Conventional technology]

Of the kinetic energy that is lost when the vehicle decelerates, the amount that is dissipated (brake, engine) mainly as heat is collected as operating hydraulic pressure and accumulated in the accumulator, and this accumulated energy is used as the starting energy and acceleration energy of the vehicle. A deceleration energy recovery device for vehicles equipped with a PTO (Power-take-off) output device or an axle equipped with a transfer has been known for a long time. The oldest was CJ Lawrence in England in 1976 when a British Leyland bus was used. Since it was announced that it is under development, various researches and developments have been conducted in Europe and the United States, and recently, JP-A-62-15128, JP-A-62-37215 and It is disclosed in Japanese Laid-Open Patent Publication No. 62-39327.

Each of the latter devices is a transmission having a multi-stage gear train mechanism that shifts and transmits the rotation of a counter shaft driven through an engine clutch, a main shaft connected to a wheel drive system, and the counter shaft to the main shaft. , T / M), the counter shaft PTO gear mounted on the counter shaft so that it can be connected and disconnected via the counter shaft PTO gear synchronizer, and this PTO gear is gear-coupled to the main shaft PTO main shaft PTO.
A multi-stage transmission type PTO device having a main shaft PTO gear that is detachably mounted via a gear synchronizer and a PTO output shaft that is driven via a drive gear that is connected to this main shaft PTO gear. Connected pump / motor, hydraulic circuit that connects the accumulator and oil tank via this pump / motor, electromagnetic clutch that enables and disconnects this hydraulic circuit and PTO shaft, and the pump / motor that controls the electromagnetic clutch. The accumulator and pump / motor connected by the high-pressure oil circuit are made to function as either one of the pump and the motor depending on the operating condition of the vehicle (that is, they function as a pump at the time of deceleration, and the rotational force of the wheels causes the PTO device to operate. Kinetic energy lost mainly as brake and engine heat by accumulating hydraulic oil in the accumulator (below , PTO generates a rotational force by the hydraulic fluid to the starting / acceleration which has been accumulated in the accumulator is recovered is referred to as braking energy)
A control unit that functions as a motor that rotationally drives the wheels through the device) is configured as a main part.

Such control means of the deceleration energy recovery device controls the capacity of the variable displacement motor (the tilt angle of the swash plate or the swash shaft) according to the amount of depression of the accelerator pedal when the vehicle starts and when the hydraulic pressure in the accumulator is sufficient. When the vehicle speed is controlled and the hydraulic clutch is used to start the vehicle by hydraulic pressure while the vehicle speed set for the gear selected by the driver is exceeded, the engine clutch is connected to drive the engine. At the same time as starting the transmission control of the PTO device, the counter shaft synchronizer that was on is turned off and the main shaft synchronizer is turned on, and only when the accelerator pedal depression amount is large at that time, the engine is driven with hydraulic pressure according to the depression amount. Control the force.

During braking, the electromagnetic clutch is connected and the tilt angle control signal (pump displacement control signal) according to the depression of the brake pedal is applied to the pump / motor to perform the pump operation, and at the same time, the control to disengage the engine clutch is performed. .

In this case, the control means collects the portion of the braking energy consumed by the engine brake based on the control program, and disconnects the engine from the drive system of the wheels during traveling by the motor. In addition to the control so that the motor and the engine are used together, or when the vehicle is started / accelerated only by the engine, the control is performed so as to be “contact”.

[Problems to be Solved by the Invention]

In the case of such a conventional technique, when the driver locks the wheel by the air brake pressure during the panic braking when the driver suddenly depresses the brake pedal, the pump that converts the driving force of the wheel into the hydraulic braking force. The rotation of the motor is stopped and the hydraulic brake operation is stopped.

However, in this case, the accumulator accumulated by the braking force remains connected to the pump / motor, so the hydraulic oil accumulated in the accumulator flows backward, causing the pump / motor to rotate in reverse and the wheels to rotate in reverse. However, since the wheels are locked by the air brake pressure, trying to reversely rotate the wheels meaninglessly distorts the braking force transmission system such as the axle and damages the axle. There was a point.

Therefore, it is an object of the present invention to realize a brake energy regeneration device for a vehicle in which a reverse rotational force due to a hydraulic circuit is not transmitted to a wheel when a panic brake is detected.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, in the present invention, at the time of regenerating the accumulated energy while hydraulically accumulating in the high pressure accumulator through the pump / motor and the circuit valve connected from the low pressure accumulator to the power branch mechanism during deceleration energy recovery, A hydraulic circuit for hydraulically releasing the high pressure accumulator to the low pressure accumulator through the circuit valve and the pump / motor, a switch that operates when the brake pedal is operated beyond a predetermined braking force, and the switch operates And a control means for setting the tilt angle of the pump / motor to 0 and shutting off the circuit valve or disconnecting the power branch mechanism from the hydraulic circuit.

[Action]

In the present invention, the control means is, for example, a panic brake pressure switch for detecting a predetermined pressure, which is provided in the brake air pipe between the brake valve and the brake cylinder. State), the tilt angle of the pump / motor is set to 0 and the circuit valve is shut off, or the power branch mechanism (either the electromagnetic clutch and the normal drive system such as the PTO device and the axle) is set to the hydraulic circuit ( (Pump / motor) control.

With this control, in the case of, the pump / motor stops rotating, and the hydraulic energy from the high-pressure accumulator is not transmitted to the pump / motor. In the case of, even if the hydraulic circuit operates, the braking force is applied to the power branch mechanism. Is not transmitted.

Therefore, in either case, the hydraulic braking force is prevented from being transmitted to the wheels via the power branch mechanism during panic braking, and the tilt angle of the pump is 0 when the brake pedal is released immediately after the vehicle is stopped in the wheel lock state. It prevents the force on the opposite phase side from working before returning to.

〔Example〕

Hereinafter, embodiments of a vehicle brake energy regeneration device according to the present invention will be described.

FIG. 1 is a configuration diagram of an embodiment of a vehicle brake energy regenerating apparatus according to the present invention, in which 1 is a PTO for extracting a driving force of wheels 21 via an axle 20 as a hydraulic braking force.
A device, 2 is an electromagnetic clutch that connects and disconnects the driving force transmission between the PTO device 1 and a pump / motor 3 that executes a pump operation during braking, 4 is a circuit shutoff valve, 5 is a high pressure accumulator, and 6 is a pump / motor. A low pressure accumulator that forms a hydraulic circuit together with 3, a circuit shutoff valve 4, and a high pressure accumulator 5, 7 is a brake air tank, 8 is a brake pedal,
9 is a brake valve that supplies air from the brake air tank 7 to a brake drum 12 described later in proportion to the amount of depression of the brake pedal 8, 10 is brake air piping connected to the brake valve 9, 11 is a brake cylinder, and 12 is A brake drum that is driven by the brake cylinder 11 to generate a braking force, 13 is a panic brake pressure switch that operates when the air in the brake air pipe 10 exceeds a predetermined pressure, and 14 is a panic brake when the panic brake pressure switch 13 operates. When the tilt angle of the pump / motor 3 is set to 0, the hydraulic circuit is disconnected by the circuit shut-off valve 4, and the electromagnetic clutch 2 is disconnected.
U).

FIG. 1 shows a state of panic braking. Therefore, the brake pedal 8 is stepped on and the brake valve 9 is opened, and the air from the air tank 7 passes through the brake air pipe 10 to the piston 11a of the brake cylinder 11. By pushing in the right direction, the brake drum 12 is operated to generate the braking force.

FIG. 2 is a flowchart of an interrupt routine stored and executed in the MPU 14 shown in FIG. 1, and the operation of the configuration shown in FIG. 1 will be described based on this.

By the driver of the vehicle stepping on the brake pedal 8,
The brake valve 9 opens and air flows from the air tank 7 to the brake air pipe 10, but this pressure has a predetermined value (for example, 4 k
If it exceeds g / cm ² ) the panic brake pressure switch 13 will operate.

The MPU 14, which has detected the panic brake state by the operation of the panic brake pressure switch 13, starts executing the interrupt routine of FIG. 2 in preference to the execution of other programs, and starts the hydraulic brake operation stop program. The tilt angle of the pump / motor 3 is set to 0 (step S in FIG. 2).
1) Prevent the reverse rotation by preventing the pump / motor 3 from rotating even if the hydraulic oil accumulated in the high pressure accumulator 5 flows backward.

Further, the circuit shutoff valve 4 is turned off (step S2 in the same step) to bring the hydraulic circuit into the shutoff state. As a result, the hydraulic oil of the high pressure accumulator cannot reach the pump / motor 3,
Therefore, the pump / motor 3 cannot rotate.

Further, the electromagnetic clutch 2 is turned off (step S3),
The pump / motor 3 is disconnected from the PTO device 1 and the wheels 21 to completely shut off the hydraulic braking force from the wheels 21.

Therefore, the reverse rotation operation of the pump motor 3 can be completely avoided even in the wheel lock state.

In the above embodiment, in order to reliably disconnect the hydraulic circuit from the wheels, the MPU 14 is connected to the pump / motor 3 and the circuit shutoff valve 4.
Although the control signals are applied to the electromagnetic clutch 2 and the electromagnetic clutch 2, respectively, it is needless to say that the disconnection between the hydraulic circuit and the wheels can be realized by executing step S1 + S2 or step S3.

Further, in the case of the circuit shutoff valve 4 described above, when the rotation direction of the pump / motor 3 is kept constant, a circuit switching valve (logic valve) can be used as the circuit valve of the hydraulic circuit.

Furthermore, in the present invention, even if the engine clutch (not shown) is in the connected state, the engine braking force is relatively small during panic braking, so that the driving force of the wheels is actually absorbed in the hydraulic circuit. Therefore, the condition of the engine clutch does not matter.

〔The invention's effect〕

As described above, in the vehicle brake energy regeneration device according to the present invention, when the panic brake state is detected by the operation of the panic brake pressure switch, the control means sets the tilt angle of the pump / motor to 0 and shuts off the circuit valve. Or the hydraulic circuit is configured to be separated from the power branch mechanism, so that even if the wheel is locked during panic braking, the reverse rotation drive force from the hydraulic circuit due to the reverse flow of hydraulic oil to the wheels via the power branch mechanism. Can be shut off. Therefore, it is possible to minimize damage to the brake transmission system such as the axle during panic braking.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a vehicle brake energy regeneration device according to the present invention, and FIG. 2 is a flow chart diagram of an interrupt routine stored in and executed by a microprocessor (MPU). . In FIG. 1, 1 is a PTO device, 2 is an electromagnetic clutch, and 3
Is a pump motor, 4 is a circuit shutoff (switching) valve, 5 is a high pressure accumulator, 6 is a low pressure accumulator, 13 is a panic brake pressure switch, 14 is an MPU, and 21 is a wheel.

Claims (1)

[Claims] 1. When the deceleration energy is recovered, the low pressure accumulator is hydraulically accumulated in the high pressure accumulator through a pump / motor and a circuit valve connected to the power branch mechanism, and when the accumulated energy is regenerated, the high pressure accumulator is used to regenerate the circuit valve. And a hydraulic circuit for releasing hydraulic pressure to the low-pressure accumulator via the pump / motor, a switch that operates when the brake pedal is operated beyond a predetermined braking force, and a pump / motor that operates when the switch operates. And a control means for turning off the circuit valve or disconnecting the power branch mechanism from the hydraulic circuit.