JP2985541B2 - Braking 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 hydraulic pump which is driven by a drive shaft of a vehicle during braking to store hydraulic energy.
The present invention relates to a braking energy regenerating device that can be used as a driving force of a vehicle by driving a motor with hydraulic energy during starting or acceleration.

[0002]

2. Description of the Related Art Braking energy regenerating devices have been developed for large vehicles, especially for route buses. Generally, in the operation of a route bus, starting and braking are repeatedly performed frequently because the distance between the bus stops is short, and each time the bus stops at the bus stop, that is, every time the braking is performed, frictional heat generated on a brake drum or the like is generated. That is, the kinetic energy of the vehicle released into the atmosphere as heat energy also increases. Therefore, it was developed to store the energy released at the time of braking as other reusable hydraulic energy, and to reduce the stored hydraulic energy to the driving force of the vehicle when starting or accelerating. It is a braking energy regeneration device.

[0003] This braking energy regenerating device mainly comprises an accumulator, a hydraulic oil tank, a hydraulic pump / motor, and various operating valves. The accumulator is connected to the hydraulic oil tank via a hydraulic pump / motor. The pump / motor shaft of the hydraulic pump / motor is connected to the drive shaft of the vehicle via a gear box with a clutch.

According to this device, at the time of braking, the hydraulic pump / motor is operated as a pump by the drive shaft of the vehicle,
Hydraulic oil supplied from a hydraulic oil tank to a hydraulic pump / motor through a hydraulic line is pressure-fed to an accumulator by the hydraulic pump / motor, and accumulates as compressed energy of nitrogen gas sealed in the accumulator. On the other hand, at the time of starting and accelerating, the hydraulic oil accumulated in the accumulator is discharged to the hydraulic oil tank through the hydraulic pump / motor and the hydraulic fluid line, so that the hydraulic pump / motor works as a motor and the drive shaft of the vehicle is driven. Assists driving force.

[0005] The hydraulic pump / motor of this regenerative device includes:
A swash plate type axial plunger type pump / motor is employed. This type of hydraulic pump / motor has a built-in swash plate. By changing the inclination angle of the swash plate, the mode can be switched to the pump or motor mode, and the discharge amount of the pump can be changed. Alternatively, the magnitude of the motor torque can be changed.

[0006]

In the above-mentioned braking energy regenerating apparatus, when the hydraulic pump / motor is not operating as a pump or a motor, the hydraulic pump / motor is in a state where the inclination angle of its swash plate is zero, that is, Since the rotation is performed with the discharge amount of the hydraulic oil being zero, the flow of the hydraulic oil does not occur, so that there is a problem that the sliding portion (rotating portion) of the hydraulic pump / motor generates heat.

In order to avoid such inconveniences, the working fluid is circulated in the housing of the hydraulic pump / motor by a gear pump driven by the pump / motor shaft of the hydraulic pump / motor to prevent such heat generation. However, the driving of the gear pump has a disadvantage that the driving shaft of the vehicle is adversely affected by torque loss via the pump / motor shaft, and the fuel consumption of the vehicle is reduced. For this reason, it is conceivable to disengage the clutch of the gear box, disconnect the pump / motor shaft from the drive shaft of the vehicle, and prevent the pump / motor shaft of the hydraulic pump / motor from being driven. However, in this case,
For example, since the depressed brake during braking, by the hydraulic pump motor operation is initiated by connecting the clutch of the gearbox, the processes such the operation of the hydraulic pump-motor Ru is resumed <br/> since goes through, the operation of the regeneration device, i.e., the raw response delay in the start of operation of the auxiliary brake
It is not preferable because there are problems such as kinking and a shock when the clutch is engaged.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a braking energy regenerating apparatus capable of preventing torque loss of a vehicle and reliably cooling a sliding portion in a hydraulic pump / motor. It is in.

[0009]

In order to achieve the above object, according to the present invention, when braking, a drive shaft of a vehicle functions as a pump, and pressurized fluid is supplied from a hydraulic fluid tank to a hydraulic accumulator through a hydraulic fluid line. When the vehicle starts and accelerates, the hydraulic fluid accumulated in the hydraulic accumulator is discharged to the hydraulic fluid tank through the hydraulic fluid line to act as a motor, and assists the driving force of the drive shaft of the vehicle. Pressure pump / motor and drain tank storing working fluid
Circulating means for circulating hydraulic fluid between the drain tank and the housing of the hydraulic pump / motor.
This circulation means is operated from the drain tank
Supplying liquid as lubricating coolant into the housing
A circulation path for collecting the hydraulic fluid used for lubrication and cooling of the sliding portion in the housing to the drain tank ,
Inserted in the supply side of the ring path, and a motor-type hydraulic pump which is intermittently driven.

[0010]

According to the braking energy regenerating apparatus of the present invention, the circulating means including the intermittently driven electric hydraulic pump is provided with a sliding portion in the housing of the hydraulic pump / motor. of lubrication and hydraulic fluid used to cool and collected to the drain tank, circulating a lubricating cooling liquid hydraulic fluid within the housing from the drain tank.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. The braking energy regenerating device is mainly
Piston type accumulator device, hydraulic pump / motor 16, hydraulic oil tank 17, gearbox 18 with clutch
And a control unit 25.

The accumulator device comprises an accumulator 1
0, and these accumulators 10 consist of hydraulic cylinders having two pressure chambers 12, 13 via a piston 11. These accumulators 10
One pressure chamber 12 is filled with nitrogen gas of a predetermined pressure, and the other pressure chamber 13 is capable of accumulating hydraulic pressure. The pressure chamber 13 is connected to the first port 16a of the hydraulic pump / motor 16 via the switching valve 15 and the pipeline P1.
The second port 16b of the hydraulic pump / motor 16 is connected to the pipeline P
2 is connected to the hydraulic oil tank 17. The hydraulic oil tank 17 is a tank having a predetermined capacity, and a predetermined amount of hydraulic oil is stored in this tank. This hydraulic oil is used not only for delivering energy but also as a cooling oil.

Reference numeral 10a in FIG. 1 indicates a bottom cap, and the bottom cap 10 of one accumulator 10 is shown.
A is provided with a stroke sensor (not shown). This stroke sensor is connected to the control unit 2
When the piston 11 in the accumulator 10 moves to the bottom cap 11a side, it detects that the piston 11 hits, and supplies this detection signal to the control unit 25.

The switching valve 15 includes a control unit 25.
And is normally in a first switching position that allows only the flow of hydraulic oil from the hydraulic pump / motor 16 to the accumulator 10, and operates the hydraulic pump / motor to start and When accelerating, it is switched to the second switching position that allows the flow of hydraulic oil from accumulator 10 to hydraulic pump / motor 16.

The hydraulic pump / motor 16 is a swash plate type axial plunger type pump, and its rotation direction is always constant. The hydraulic pump / motor 16 is controlled by the control unit 25 via an electric hydraulic pump (not shown) provided separately with the inclination of the swash plate, operates as a pump during braking, starts and accelerates. Sometimes it operates as a motor. The hydraulic pump / motor 16 operates in a neutral state between the pump and the motor when the vehicle is stopped and the vehicle runs normally.

The hydraulic pump / motor 16 has a housing, which is provided with a drain port 16c and an inlet 16d for hydraulic oil. A drain tank 20 is connected to the drain port 16c via a pipe P4.
The switching control valve 30 is connected via the hydraulic pump 21 and the check valve. The hydraulic pump 21 is an electrically driven pump and is electrically controlled by a control unit 25. The switching control valve 30 has an inlet 1 of the hydraulic pump / motor 16 via a line P5 and a line P6.
The hydraulic oil tank 17 is connected via the.

The switching control valve 30 is an electromagnetic switching valve having two positions in three directions, and is electrically connected to and controlled by the control unit 25. This switching control valve 30
Is usually the hydraulic pump 21 from the drain tank 20 side.
The first switching position 30a allows the flow of the hydraulic oil to the hydraulic oil tank 17 side through the like, and when energized, the hydraulic oil flows from the drain tank 20 side to the inlet 16d of the hydraulic pump / motor 16 through the hydraulic pump 21 or the like. The second switching position 30b allows the flow of the air.

On the other hand, surplus hydraulic oil lubricated inside the hydraulic pump / motor 16 is discharged to the drain tank 21 through the pipeline P4. Note that reference numeral 32 in FIG.
Indicates a level switch, and the level switch 3
When the level of the hydraulic oil in the drain tank 20 becomes equal to or more than a predetermined amount, the hydraulic pump 21 is operated via the control unit 25, and the check valve 31, the switching control valve 30, and the line 6 The working oil is supplied to the working oil tank 17 through the port. The hydraulic oil tank 17
Similarly, when the working oil inside the tank becomes equal to or less than the set capacity, the working oil is supplied from the drain tank 20 side to the working oil tank 17 side.

The control unit 25 switches the switching control valve 30 to the second switching position 30b at regular intervals,
Hydraulic oil is supplied from the drain tank 20 to the inlet 16 of the hydraulic pump / motor 16 through the hydraulic pump 21, the check valve 31, the switching control valve 30, and the pipeline P5. As a result, the hydraulic oil is periodically circulated in the housing of the hydraulic pump / motor 16, and heat generation of the sliding portion (rotating portion) in the hydraulic pump / motor 16 is prevented.

An air tank 19 is connected to the hydraulic oil tank 17 via a pipe P3. Actually, an air supply valve (not shown) for controlling the supply of air pressure from the air tank 19 to the hydraulic oil tank 17 is provided in the pipeline P3. These valves control air pressurization to the hydraulic oil surface in the hydraulic oil tank 17 to enhance pump suction performance when the hydraulic pump / motor 16 operates as a pump. This can also prevent cavitation at the pump suction port of the hydraulic pump / motor 16.

A relief pipe (not shown) is connected between the hydraulic oil tank 17 and the switching valve 15.
Actually, when the hydraulic pressure of the hydraulic oil in the accumulator 10 reaches a predetermined pressure by the relief valve provided inside the switching valve 15, the high-pressure hydraulic oil is returned from the switching valve 15 to the hydraulic oil tank 17 through the relief line. It is. As shown in FIG. 1, the pump / motor shaft of the hydraulic pump / motor 16 can be connected to a connection shaft J1 via a clutch-equipped gear box 18, and the connection shaft J1 is connected to a differential gear 22. Is connected to the axle of the drive wheels of the vehicle. In addition, the differential gear 2
2 is connected to the output shaft of the transmission 23 of the engine 24 via the propeller shaft J2.

The clutch of the gear box 18 is electrically connected to the control unit 25. When an ON signal is supplied from the control unit 25 and the clutch is turned on, the pump shaft of the hydraulic pump / motor 16 and its Connecting the gear train, i.e. the drive axle of the vehicle,
Conversely, when an off signal is supplied from the control unit 25 and the clutch is turned off, the pump shaft of the hydraulic pump / motor 16 is disconnected from the drive axle of the vehicle. The clutch is normally connected, and is disengaged during high-speed running or the like.

On the other hand, the control unit 25 comprises a microcomputer or the like. The control unit 25 includes, in addition to the switching valve 15, the clutch of the gear box 18 and the hydraulic pump for switching the mode of the hydraulic pump / motor 16, Various sensors are connected. That is, the brake sensor 26 and the accelerator sensor 27 are electrically connected to the control unit 25, respectively.

When the brake pedal is operated, the brake sensor 26 supplies the sensor signal to the control unit 25. When the accelerator pedal is operated, the accelerator sensor 27 supplies a sensor signal to the control unit 25. Next, the accumulator 10
The main and sub air tanks 19,
The operation of the above-described braking energy regenerating device will be described on the assumption that the air pressure is accumulated in the braking device 20. When starting and accelerating, the accelerator pedal is operated, and a sensor signal is sent from the accelerator sensor 27 to the control unit 25.
The control unit 25 determines that the vehicle is starting or accelerating, and switches the switching valve 15 of the accumulator 10 to the second switching position, while switching the hydraulic pump / motor 16 to the motor mode. . At this time, the hydraulic oil accumulated in the accumulator 10 is supplied to the hydraulic oil tank 1 through the hydraulic pump / motor 16 and the pipeline P2.
7, the hydraulic pump / motor 16 generates a torque which is transmitted via a gearbox 18 to the drive axle of the vehicle. As a result, the driving force of the vehicle is
Since the torque of the hydraulic pump / motor 16 is assisted, the vehicle can smoothly start and accelerate.

At this time, the control unit 25 detects that the piston hits the stroke sensor 11a, switches the switching valve 15 to the first switching position, and stops the discharge of the hydraulic oil from the accumulator 10. Therefore, the vehicle runs only with the driving force of the engine 24 as in a normal vehicle. At this time, the hydraulic pump / motor 1
The swash plate 6 is tilted to zero (zero) and driven in a neutral state between the pump and the motor.

At the time of braking, when the brake pedal is operated and a sensor signal is supplied from the brake sensor 26 to the control unit 25, the control unit 25
When it is determined that braking is being performed, the switching valve 15 of the accumulator 10 is switched to the first switching position.
The motor 16 is switched to the pump mode. At this time, the driving force of the vehicle is transmitted from the driving axle to the pump shaft of the hydraulic pump / motor 16 via the gear box 18, and the hydraulic pump / motor 16 supplies the hydraulic oil from the hydraulic oil tank 17 through the pipelines P2 and P1. The pressure is fed to the accumulator 10 to accumulate the hydraulic pressure. When the hydraulic pressure is accumulated in the accumulator 10 to a predetermined pressure, the high-pressure hydraulic oil is returned to the hydraulic oil tank 17 via the relief pipe P3.
At this time, the nitrogen gas in the accumulator 10 is compressed,
The driving force of the vehicle, that is, the kinetic energy is stored in the accumulator 10 as the static pressure energy of the nitrogen gas.
In this way, the accumulated pressure energy stored in accumulator 10 is used again when starting and accelerating.

According to the above-mentioned braking energy regenerating device,
Since the hydraulic oil is supplied by the electric drive type hydraulic pump 21, there is no extra pump driven by the pump / motor shaft of the hydraulic pump / motor, and the adverse effect of torque loss on the drive shaft of the vehicle can be prevented. This has the effect of improving the fuel economy of the vehicle. Further, since torque loss can be prevented, there is no need to disengage the clutch of the gear box 18, and there is no response delay in operation of the regenerative device and no shock due to clutch connection. Furthermore, the hydraulic oil is supplied to the housing of the hydraulic pump / motor 16 at regular intervals and is circulated.
When the motor 16 is not operating as a pump and a motor, an effect is obtained that even if the sliding portion in the hydraulic pump / motor 16 generates heat, it can be reliably cooled.

The present invention is not limited to the embodiment described above, and it goes without saying that various modifications are possible. For example, while the switching control valve 30 is switched to the second switching position 30b at regular intervals, the switching control valve 30 may be switched at a constant rotational speed of the pump / motor shaft of the hydraulic pump / motor 16, or the hydraulic pump / motor The switching may be performed when the temperature inside 16 becomes equal to or higher than a predetermined temperature.

[0029]

As described above, the braking energy regenerating apparatus of the present invention includes an electric hydraulic pump driven intermittently by its circulation means. Since there is no extra pump driven by the motor shaft, it is possible to prevent the drive shaft of the vehicle from being adversely affected by torque loss, and to obtain an effect of improving the running fuel efficiency of the vehicle. Further, since the hydraulic fluid is intermittently circulated in the housing, even if the sliding portion in the hydraulic pump / motor generates heat, it is possible to surely cool the sliding portion.

[Brief description of the drawings]

FIG. 1 is a schematic system configuration diagram of a braking energy regeneration device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Accumulator 15 Switching valve 16 Hydraulic pump / motor 17 Hydraulic oil tank 18 Gear box (with clutch) 19 Air tank 20 Drain tank 21 Hydraulic pump 25 Control unit 30 Switching control valve 32 Level switch P1, P2, P3, P4, P5, P6 Pipeline

Claims (1)

(57) [Claims] At the time of braking, the drive shaft of the vehicle functions as a pump, and the hydraulic fluid is pumped from a hydraulic fluid tank to a hydraulic accumulator through a hydraulic fluid line to accumulate the pressure. A hydraulic pump / motor that functions as a motor by discharging the stored hydraulic fluid to the hydraulic fluid tank through the hydraulic fluid line and assists the driving force of the drive shaft of the vehicle, and a drain tank that stores the hydraulic fluid. And this drainer
Between the tank and the hydraulic pump-motor in the housing
Circulating means for circulating the working fluid, wherein the circulating means removes the working fluid from the drain tank.
The lubricating coolant is supplied into the housing.
The circulation through collecting the operating fluid used for lubrication and cooling of the sliding portion within the housing to the drain tank
Road and the inserted into the feed side of the circulation path, the braking energy recovery device characterized by comprising an electric type hydraulic pump which is intermittently driven.