JPH05131863A - Deceleration energy recovery device for four-wheel drive vehicle - Google Patents

Abstract

PURPOSE:To provide a deceleration energy recovery device with simple structure in a four-wheel drive vehicle for driving front wheels or rear wheels by a hydraulic motor. CONSTITUTION:When the braking time of a vehicle is detected by a braking time detecting means 26, a controller 28 controls an oil passage switching means 25 to accumulate discharge oil from a hydraulic pump 22 and a hydraulic motor 23 into an accumulating means 24. When the redriving time is detected by a redriving time detecting means 27, the controller 28 controls the oil passage switching means 25 to supply the operating oil accumulated in the accumulating means 24 to the intake side port of the hydraulic pump 22 or hydraulic motor 23-At the redriving time, the operation of the hydraulic pump 22 or hydraulic motor 23 is thereby assisted by slowing-down energy accumulated at the braking time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deceleration energy recovery system for vehicles.

[0002]

2. Description of the Related Art A deceleration energy recovery device for recovering deceleration energy of a vehicle, accumulating it in an accumulator, and utilizing the accumulated energy for driving energy of the vehicle is disclosed in, for example, Japanese Patent Application Laid-Open No. 61-175150.

In the deceleration energy recovery device described above, the rotational power of the wheels is transmitted to the hydraulic pump motor via the power take-out device when the vehicle is decelerated, and the hydraulic pump motor accumulates energy in the accumulator.
Then, when the vehicle starts, the hydraulic pump motor is operated as a motor by the energy accumulated in the accumulator, and the rotational power of the pump motor is transmitted to the wheels via the power take-out device.

That is, since the deceleration energy is recovered and used as the starting energy, the fuel consumption performance of the vehicle is improved.

[0005]

By the way, the rotational power from the engine is transmitted to either one of the front wheel side and the rear wheel side via a mechanical structure, and the hydraulic pump and the hydraulic line are provided on the other side. A four-wheel drive system that transmits via a hydraulic motor is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-176734.

FIG. 4 is a block diagram of the above-described hydraulic pump and the like.
It is a schematic block diagram of a wheel drive device.

In the figure, reference numeral 31 is an engine, and the rotational power of the engine 31 is transmitted through a transmission 31b and a differential gear 31e to drive wheels 31g and 31.
is transmitted to h. Further, 32 is a hydraulic pump, and this hydraulic pump 32 is driven by the engine 31. The hydraulic pump 32 is connected to the hydraulic motor 33 via hydraulic lines 36 and 37. The rotational power of the hydraulic motor 33 is transmitted to the drive wheels 33d and 33e via the differential gear 33b.

In the case of four-wheel drive and the vehicle is being driven in the forward direction, the switching valve 35
Is set to the switching position 35A as shown, and the switching valve 35 is set to the switching position 35B when the vehicle is driven in the backward direction.

In the four-wheel drive system for driving the front wheels or the rear wheels by the above-mentioned hydraulic motor, since the hydraulic pipe from the hydraulic pump to the hydraulic motor can be bent,
Compared to a four-wheel drive device having only a mechanical structure, the structure is more flexible and the degree of freedom in designing the chassis and the like can be increased.

Now, it is conceivable to improve the fuel consumption performance by applying the above-mentioned deceleration energy recovery device to a four-wheel drive vehicle in which front wheels or rear wheels are driven by this hydraulic motor.

However, when the deceleration energy recovery device described above is applied to the four-wheel drive vehicle, a power take-out device, a hydraulic pump motor, a hydraulic line, an accumulator and the like must be additionally provided. For this reason, the structure becomes complicated, the vehicle weight increases, and the price becomes high.

[0012]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention, as shown in FIG. 1, is such that rotational power from a main engine is mechanically applied to either the front wheel side or the rear wheel side. Is a four-wheel drive vehicle in which the rotational power from the main prime mover is transmitted to the other of the front wheel side or the rear wheel side via a hydraulic pump and a hydraulic motor. A deceleration energy recovery device that recovers deceleration energy during use and uses it as drive energy when the vehicle is re-driven, and is a pressure accumulating means 24 that accumulates working hydraulic pressure discharged from the hydraulic pump 22 and the hydraulic motor 23 during braking of the vehicle.
And the discharge port of the hydraulic pump 22 and one port of the hydraulic motor 23 are electrically connected via the first oil passage, and the suction port of the hydraulic pump 22 and the other port of the hydraulic motor 23 are connected to the second oil passage. A first state in which the pressure accumulating means 24 is in non-conduction with the first and second oil passages while being electrically connected through the passage, and the discharge oil from the hydraulic motor 23 in the first and second oil passages. A second state in which one of the oil passages is supplied with the pressure accumulating means 24 is in conduction, and the pressure accumulating means 24 is in conduction only with the suction port of the hydraulic pump 22, or the pressure accumulating means 24 is in contact with the hydraulic motor 23. An oil passage switching means 25 capable of switching between a third state in which only one port serving as a suction side port is brought into conduction, a braking time detecting means 26 for detecting a braking time of the vehicle, and a re-driving time of the vehicle. The re-driving detection means 27 for detecting the During normal running, the oil passage switching means 25 is controlled so as to be in the first state, and when the vehicle is being braked, in response to a detection signal from the braking time detecting means 26, the oil state is brought into the second state. The oil passage switching means 2 is controlled so as to be in the third state by controlling the passage switching means 25 and responding to the detection signal from the re-driving time detecting means 27 when the vehicle is restarted.
The controller 28 for controlling the No. 5 is provided.

Further, in the deceleration energy recovery system shown in FIG. 1, the hydraulic motor 23 is a variable hydraulic motor whose intake and discharge directions can be switched while keeping the same rotation direction. It may be configured such that the suction / ejection direction is switched according to a command signal from the controller 28 at times.

[0014]

When the vehicle is braked, the oil passage switching means 25 is brought into the second state by the controller 28, and the hydraulic pump 2
2 and the working hydraulic pressure discharged from the hydraulic motor 23 are accumulated in the pressure accumulating means 24. And when the vehicle is restarted,
The oil passage switching means 25 is controlled by the controller 28 so that the third
Then, the working hydraulic pressure accumulated in the pressure accumulating means 24 is supplied to the hydraulic pump 22 or the hydraulic motor 23. Therefore, when the vehicle is re-driven, the operation of the hydraulic pump 22 or the hydraulic motor 23 is assisted by the operating hydraulic pressure from the pressure accumulating means 24.

[0015]

FIG. 2 is a schematic configuration diagram of an embodiment of the present invention.

In the figure, 1 is an engine (main motor), 1a is a main transmission, 1c is a front wheel differential gear, 1b is a front wheel drive shaft, 1d and 1e are front wheels, and these front wheels 1d and 1e are engines. Rotational power from 1 is transmitted through a mechanical structure. Reference numeral 2 denotes a hydraulic pump that is interlocked with the main transmission 1a.
Rotates in proportion to the vehicle speed. Further, 3 and 4 are hydraulic motors, and these hydraulic motors 3 and 4 are hydraulic lines 2
It is connected to the hydraulic pump 2 via 1a and 21b. The hydraulic line 21a has a high pressure when the vehicle moves forward, and the hydraulic line 21b has a high pressure when the vehicle moves backward. 2a
Is an actuator for changing the swash plate angle of the hydraulic pump 2, 3a is an actuator for changing the swash plate angle of the hydraulic motor 3, and 4a is an actuator for changing the swash plate angle of the hydraulic motor 4. 3b is a reduction gear of the hydraulic motor 3; 4b is a reduction gear of the hydraulic motor 4; It is a drive shaft for transmission. Further, 1f and 1g are front wheels 1d and 1 respectively.
Rotation sensors 3e and 4e for detecting the rotation speed of e are rotation sensors for detecting the rotation speeds of the rear wheels 3d and 4d, respectively. 5a and 5b are check valves for preventing backflow arranged between the hydraulic lines 21a and 21b, 11 is a charge pressure storage charge pump connected between the check valves 5a and 5b, and 6b is a charge pressure It is a relief valve.
Reference numeral 7a is a line pressure sensor that detects the line pressure (working oil pressure) of the hydraulic conduit 21a, and 7b is a line pressure sensor that detects the line pressure (working oil pressure) of the hydraulic conduit 21b. 6a is a relief valve, which is connected to the pump side of the hydraulic line 21a via a check valve 5c and to the motor side of the hydraulic line 21a via a check valve 5d. Further, the relief valve 6a is the check valve 5
It is connected to the pump side of the hydraulic line 21b via f, and is connected to the motor side of the hydraulic line 21b via a check valve 5e. 10 is a tank connected to the relief valve 6a. Then, the relief valve 6a is connected to the hydraulic line 21a or 2
When a momentary abnormal high pressure is generated in 1b, pressure oil is discharged to the tank 10 to protect the system.
Reference numeral 8 is an accelerator sensor (re-driving time detecting means), 14 is a brake sensor (braking time detecting means), and 9 is a controller. Reference numeral 12 is a control pressure accumulator, and this pressure accumulator 1
The hydraulic pressure for changing the swash plate angle is supplied from 2 to the actuators 2a, 3a, 4a.

The rotation sensors 1f, 1g, 3e, 4
Based on the detection signals from e, the line pressure sensors 7a and 7b, and the accelerator sensor 8, the controller 9 controls the actuators 2a and 3 to control the two-wheel drive and the four-wheel drive.
A control signal is supplied to a and 4a. Thereby, the line pressure and the discharge flow rate of the hydraulic motors 3 and 4 are controlled, and the operations of the hydraulic pump 2 and the hydraulic motors 3 and 4 are controlled.

Reference numeral 13 is a switching valve arranged in the hydraulic line 21a, and 18 is a high pressure side accumulator (pressure accumulating means). When the switching valve 13 is on the 13A side, the first port 2f of the hydraulic pump 2 and the accumulator 18 are connected. Is cut off. When the switching valve 13 is on the 13B side, the first
The port 2f and the accumulator 18 are brought into conduction. Reference numeral 17 is a switching valve, and 19 is a low pressure side accumulator for compensating the flow rate when hydraulic oil flows in and out of the accumulator 18, as will be described later. When the switching valve 17 is on the 17A side, the high pressure side accumulator 18
And the pump side of the hydraulic line 21b are brought into conduction, and the motor side of the hydraulic line 21b and the low pressure side accumulator 19 are brought into conduction. In addition, the switching valve 17 is 17B
On the side, the high pressure side accumulator 18 and the low pressure side accumulator 19 and the pump side of the hydraulic line 21b are cut off, and the pump side of the hydraulic line 21b and the motor side are brought into conduction. Reference numeral 16 is a variable throttle, and the hydraulic line 21 a is connected to the low pressure side accumulator 19 and the charge pump 11 via the variable throttle 16. Reference numeral 20 denotes a switching valve. When the switching valve 20 is on the 20A side, the hydraulic pipe 21a side and the first ports 4f of the hydraulic motors 3 and 4 are brought into conduction, and the hydraulic pipe 21b is connected.
Side and the second port 4s of the hydraulic motors 3, 4 are brought into conduction. When the switching valve 20 is on the 20B side, the hydraulic line 21a side and the second port 4s are in the conductive state, and the hydraulic pipe line 21b side and the first port 4f are in the conductive state. The switching valves 13, 17, 20 constitute oil passage switching means.

In the above structure, the vehicle is traveling normally (2
For steady running and accelerating running in the four-wheel drive and four-wheel drive states, the changeover valves 13, 17, 20 are driven by the signals from the controller 9 on the 13A side, 17B side, and 2B side, respectively.
It is on the 0A side (first state). Further, during normal traveling, the variable diaphragm 16 is in the most closed state by the signal from the controller 9.

When it is detected by the brake sensor 14 that the brake pedal is turned on or the like, the controller 9 supplies command signals to the actuators 2a, 3a and 4a, respectively. To zero. Subsequently, the controller 9 sets the switching valves 13 and 20 to the 13B side and the 20B side, respectively (second state). Then, the oil discharged from the first port 2f of the hydraulic pump 2 is accumulated in the accumulator 18 via the hydraulic line 21a and the switching valve 13 according to the brake pedal force, the vehicle behavior, and the like, and the hydraulic motors 3 and 4 are driven. The oil discharged from the second port 4s is the switching valve 20 and the hydraulic line 2.
1a, accumulated in the accumulator 18 via the switching valve 13 (accumulation of deceleration energy).

When it is detected that the brake pedal is turned off or the braking is released, the switching valve 1
3 and 20 are the 13A side and the 20A side, respectively.

Next, when the accelerator pedal is turned on during re-driving of the vehicle, the accelerator sensor 8 detects this, and the controller 9 fully opens the variable throttle 16 and sets the switching valve 17 to the 17A side (No. 1). State 3). Then, the hydraulic oil accumulated in the accumulator 18 is transferred to the switching valve 1
7, is supplied to the second port 2s of the hydraulic pump 2 via the hydraulic pipe 21b to assist the operation of the hydraulic pump 2 (collection of accumulated deceleration energy). Then, after the lapse of a predetermined time after the accelerator pedal is turned on, the switching valve 17 is set to the 17B side, and the variable throttle 16 is brought into the most closed state.

As described above, according to the embodiment of the present invention, the first state during normal traveling of the vehicle, the second state in which deceleration energy during braking is accumulated in the accumulator 18, and the accumulator 18 The third state in which the hydraulic energy stored in the valve is used for the re-driving energy, and the switching valves 17, 1 based on the signal from the controller 9
It can be selected by the operations of 3, 20.
As a result, it is not necessary to separately provide a hydraulic pump motor and a power take-out device, and it is not necessary to add a large hydraulic line. Therefore, it is possible to provide the deceleration energy recovery device with a simple configuration and at a low cost in a four-wheel drive vehicle that drives the front wheels or the rear wheels with the hydraulic motor.

FIG. 3 is a schematic block diagram of another embodiment of the present invention, in which components equivalent to those in FIG. 2 are designated by the same reference numerals.

In FIG. 3, reference numerals 30 and 40 denote hydraulic motors that can change the suction direction and the discharge direction in the same rotation direction. That is, the swash plate angles of the hydraulic motors 30 and 40 can be changed from the plus side to the minus side.
It is possible to change the port 40f to the suction side and the second port 40s to the discharge side, or the first port 40f to the discharge side and the second port 40s to the suction side. Therefore, in the example of FIG. 3, the switching valve 20 of the example of FIG. 2 is omitted, and the switching valves 13 and 17 constitute oil passage switching means.

In the example of FIG. 3, while the vehicle is normally traveling, the switching valve 13,
17 are on the 13A side and 17B side, respectively (first
Condition). Further, the variable throttle 16 is in the most closed state, the swash plate angle of the hydraulic motors 30, 40 is on the plus side, the first port 40f is on the suction side, and the second port 40s is on the discharge side.

When the vehicle changes from the normal running state to the braking state, the controller 9 sets the discharge amounts of the hydraulic pump 2 and the hydraulic motors 30 and 40 to zero. Subsequently, the controller 9 sets the switching valve 13 to the 13B side, sets the swash plate angle of the hydraulic motors 30 and 40 to the negative side, and sets the first port 40f to the discharge side and the second port 40s to the suction side (the first side). State 2). Then, the hydraulic pump 2 and the hydraulic motors 30, 40 are selected according to the brake pedal force, the vehicle behavior, and the like.
The discharge oil from is accumulated in the accumulator 18.

When the braking state is released, the swash plate angles of the hydraulic motors 30 and 40 are set to zero and the switching valve 13 is set to the 13A side.

Next, when the accelerator pedal is turned on at the time of re-driving the vehicle, the controller 9 fully opens the variable throttle 16 and sets the switching valve 17 to the 17A side (third state). Then, the hydraulic oil accumulated in the accumulator 18 assists the operation of the hydraulic pump 2.
Then, after the lapse of a predetermined time after the accelerator pedal is turned on, the switching valve 17 is set to the 17B side, and the variable throttle 16 is brought into the most closed state. According to the example of FIG. 3 described above, similarly to the example of FIG. 2, the deceleration energy recovery device can be provided in a four-wheel drive vehicle that drives the front wheels or the rear wheels by the hydraulic motor with a simple configuration and at a low cost. it can.

In the examples of FIGS. 2 and 3, instead of the variable throttle 16, a switching valve for switching between conduction and non-conduction of the oil passage may be used.

Further, in the above-mentioned example, the switching valve 13
Is set to the 13B side when the braking state is released, and is set to the 13A side when the braking state is released. However, the 13B side is maintained even when the braking state is released, and the 13A side is set after the accelerator pedal is turned on. It may be configured as follows.

Further, in the above example, the switching valve 1
No. 7 is configured to switch to the 17B side after a predetermined time has elapsed since the accelerator pedal was turned on.
The switching valve 17 may be switched to the 17B side when the hydraulic pressure in the hydraulic pressure pipe 21a reaches a predetermined value based on the pressure detection signal from a.

Further, in the above-described example, the low pressure side accumulator 19 is provided for compensating the flow rate when the hydraulic oil flows in and out of the high pressure side accumulator 18, but instead of the accumulator 19, for example, a charge pump. May be used to perform the flow rate compensation.

Further, while the accumulator 18 is connected to the second port of the hydraulic pump 2 when the vehicle is re-driven, the accumulator 18 is connected to the suction side port of the hydraulic motor 3, 4 or 30, 40 when the vehicle is re-driven. The operation of the hydraulic motors 3, 4 or 30, 40 may be assisted.

According to this embodiment, since the switching valve 20 in the above-mentioned embodiment can be omitted, there is an effect that the weight is reduced, the weight is reduced, and the space can be saved.

[0036]

As described above, according to the present invention, the rotational power from the main prime mover is mechanically transmitted to either the front wheel side or the rear wheel side, and either the front wheel side or the rear wheel side is Is a four-wheel drive vehicle in which the rotational power from the main prime mover is transmitted to the other side of the four-wheel drive vehicle through a hydraulic pump and a hydraulic motor, and the deceleration energy during braking of the four-wheel drive vehicle is recovered to restart the vehicle. A deceleration energy recovery device for use in driving energy of a hydraulic pump, comprising a pressure accumulating means for accumulating working hydraulic pressure discharged from a hydraulic pump and a hydraulic motor during braking of a vehicle, and a discharge port of the hydraulic pump and one port of the hydraulic motor. The first oil passage is electrically connected, and the suction port of the hydraulic pump and the other port of the hydraulic motor are electrically connected via the second oil passage, and the pressure accumulating means is connected to the first and second oil passages. And non-conduction A first state in which the first and second
A second state in which one of the oil passages to which the discharge oil from the hydraulic motor is supplied and the pressure accumulating means are electrically connected, and whether the pressure accumulating means is electrically connected only to the suction port of the hydraulic pump. Alternatively, an oil passage switching means capable of switching the pressure accumulating means to a third state in which only one port serving as a suction side port of the hydraulic motor is electrically connected, a braking time detecting means for detecting a braking time of the vehicle, and a vehicle Of the re-driving time detecting means for detecting the re-driving time of the vehicle, and the oil passage switching means for controlling the oil passage switching means to be in the first state when the vehicle is in a steady running state. In response, the oil passage switching means is controlled so as to be in the second state, and when the vehicle is restarted, in response to the detection signal from the restarting detection means, the oil path switching means is brought into the third state. A controller for controlling the path switching means, Since form was a simple structure and low cost, the reduction energy recovery device can be arranged in four-wheel drive vehicle described above.

[Brief description of drawings]

FIG. 1 is a diagram for responding to a complaint.

FIG. 2 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of another embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a conventional example.

[Explanation of symbols]

2, 22 ... Hydraulic pump, 3, 4, 23, 30, 40 ... Hydraulic motor, 8 ... Accelerator sensor, 9, 28 ... Controller, 13, 17, 20 ... Switching valve, 14 ... Brake sensor, 18 ... Accumulator, 24 … Accumulator, 25…
Oil passage switching means, 26 ... Braking detection means, 27 ... Re-driving detection means.

Claims (2)

[Claims] 1. Rotational power from a main prime mover is mechanically transmitted to either the front wheel side or the rear wheel side, and a hydraulic pump and a hydraulic motor are provided on the other side of the front wheel side or the rear wheel side. A four-wheel drive vehicle in which the rotational power from the main motor is transmitted via a vehicle, and a deceleration energy recovery device that recovers deceleration energy during braking of the four-wheel drive vehicle and uses it as drive energy during vehicle re-drive. There is a pressure accumulating means for accumulating the working hydraulic pressure discharged from the hydraulic pump and the hydraulic motor when the vehicle is braked, and the discharge port of the hydraulic pump and one port of the hydraulic motor are electrically connected via the first oil passage, And a first state in which the suction port of the hydraulic pump and the other port of the hydraulic motor are electrically connected via the second oil passage, and the pressure accumulating means is electrically disconnected from the first and second oil passages, First and first Among the oil passage, and a second state to conduct a one of the oil passage and the pressure accumulating means for discharging oil from the hydraulic motor is supplied,
An oil passage switching means capable of switching between a third state in which the pressure accumulating means is brought into conduction only with the suction port of the hydraulic pump, or the pressure accumulating means is brought into conduction with only one port which is the suction side port of the hydraulic motor. Braking time detecting means for detecting when the vehicle is braking, re-driving time detecting means for detecting when the vehicle is re-driving, and oil passage switching means are controlled so as to be in the first state during steady running of the vehicle. When the vehicle is being braked, the oil passage switching means is controlled so as to be in the second state in response to the detection signal from the braking time detecting means, and when the vehicle is re-driving, the oil pressure switching means receives the detection signal from the re-driving time detecting means. In response, a deceleration energy recovery system for a four-wheel drive vehicle, comprising: a controller that controls the oil passage switching means so as to be in the third state. 2. The deceleration energy recovery system according to claim 1, wherein the hydraulic motor is a variable hydraulic motor whose suction and discharge directions can be switched while keeping the same rotational direction, and the variable hydraulic motor is used when braking the vehicle. A deceleration energy recovery device configured to switch the suction and discharge directions according to a command signal from the controller.