JPH03206322A - Hydraulic driving gear for vehicle - Google Patents

Abstract

PURPOSE:To improve efficiency in utilizing pressure oil by driving each oil hydraulic motor in series or parallel connection in accordance with a room- cooling load, in a vehicle provided with the first oil hydraulic motor for driving a refrigerant compressor and the second oil hydraulic motor for driving a cooling fan. CONSTITUTION:The first oil hydraulic motor 3 for driving a refrigerant compressor 32 built in a room-cooling device 31, second oil hydraulic motor 4 for driving a radiator cooling fan 41 and the third oil hydraulic motor 5 for driving an alternator 51 are interposed halfway in a hydraulic circuit 7 in which delivery oil of an oil hydraulic pump 2 driven by an engine 21 is supplied. A flow path selector valve 82 is interposed in the hydraulic circuit 7 to make it possible to form the halfway of the hydraulic circuit 7 into the first route 8 for connecting in series the first and second oil hydraulic motors 3, 4 and the second route 9 for connecting in parallel the first and second oil hydraulic motors 3, 4. The flow path selector valve 82 is selected in accordance with a room cooling load to select the first route 8, when the room cooling load is in a large value, and the second route 9, when the room cooling load is in a small value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic drive system for a vehicle that drives a refrigerant compressor, cooling fan, etc. using pressure oil discharged from a hydraulic pump. [Conventional Technology] Conventionally, as shown in FIG.
Hydraulic motors 107 and 108 connected to the drive shafts of vehicle auxiliary equipment such as the refrigerant compressor 104 of the cooling system M103 and the radiator cooling fan 105, as well as the power steering A conventional device A for driving the device 106 has been proposed. This conventional device A has a control circuit 109 that controls the hydraulic motor 10.
The amount of pressure oil led to 7, 108 and the hydraulic motor 107, 10
The rotational speed of the refrigerant compressor 104 and the cooling fan 105 was controlled by adjusting the amount of pressure oil guided to the bypass passages 110 and 111 by bypassing the refrigerant compressor 104 and the cooling fan 105. Furthermore, in Japanese Patent Application Laid-Open No. 62-282110, two hydraulic motors connected to the drive shaft of one radiator cooling fan are connected in series on the hydraulic circuit in the low engine speed range, and Conventional device B has been proposed in which two hydraulic motors are connected in parallel on a hydraulic circuit in the rotation speed range. Furthermore, this conventional FIB adjusts the amount of pressure oil guided to the two hydraulic motors by the control circuit and the amount of pressure oil guided to the bypass flow path bypassing the two hydraulic motors, depending on the engine cooling water temperature. The number of rotations of the cooling fan was controlled. [Problems to be Solved by the Invention] However, in the conventional device A described above, the energy of the pressure oil guided to each bypass flow path 110, 111 was not effectively used and was wasted.

In addition, in the conventional 1FB described above, when the engine speed reaches the high engine speed range and the amount of pressurized oil is larger than necessary, or even if the engine speed is in the low engine speed range, the engine cooling water When the temperature was low, most of the pressure oil discharged from the hydraulic pump was led to a bypass flow path and discarded. For this reason, the energy efficiency of the device deteriorates and the oil temperature increases, requiring a large oil cooler.

In particular, in the conventional device A, the power required for the hydraulic motor 107 that drives the refrigerant compressor 104 accounts for most of the power of the entire device. Further, as shown in FIG. 3, even if the rotational speed N6 of the refrigerant compressor 104 decreases, the drive oil pressure ΔPc of the hydraulic motor does not decrease much, so the bypass flow path 11
There is a large loss of energy in the pressure oil flowing through 0.

By the way, the cooling capacity required of the air conditioner 103 differs greatly depending on whether you want to rapidly lower the temperature inside the vehicle by getting into a vehicle that has been left out in the hot sun, or when you are driving normally in spring or autumn. Therefore, the minimum rotation speed of the refrigerant compressor 104 needs to be lowered by about 10% of the maximum rotation speed.

Therefore, when the refrigerant compressor 104 is driven at the lowest rotational speed, most of the pressure oil discharged from the hydraulic pump 102 flows through the bypass passage 110, and almost no energy of the pressure oil is used. loss is very large.

An object of the present invention is to provide a hydraulic drive system for a vehicle that reduces energy loss of pressure oil.

[Means for Solving the Problems] A hydraulic drive system for a vehicle according to the present invention includes a hydraulic bomb driven by an engine and a drive shaft of a refrigerant compressor incorporated in an air conditioner, and a refrigerant compressor discharged from the hydraulic pump. a first hydraulic motor driven by pressure oil; a second hydraulic motor connected to a drive shaft of a cooling fan that blows air to the heat exchanger and driven by pressure oil discharged from the hydraulic pump; a first path in which the first hydraulic motor and the second hydraulic motor are connected in series, and the pressure oil discharged from the hydraulic bomb is guided to the first hydraulic motor and then to the second hydraulic motor; A hydraulic circuit having a second path in which a first hydraulic motor and a second hydraulic motor are connected in parallel to separately guide pressure oil discharged from the hydraulic pump to the first hydraulic motor and the second hydraulic motor. and a switching means having a detection means for detecting a cooling load of the cooling device and switching between the first route and the second route according to the cooling load detected by the detection means, and the second route. and adjusting means for adjusting the flow rate distribution of pressure oil guided to the first hydraulic motor and the second hydraulic motor when the hydraulic motor is in the state.

[Operation] When the cooling load of the cooling device is large, the switching means switches to the first path and all the pressure oil discharged from the hydraulic pump is guided to the first hydraulic motor connected to the drive shaft of the refrigerant compressor. Rotate the refrigerant compressor at high speed. and,
The pressure oil that drove the first hydraulic motor is guided to a second hydraulic motor connected to the drive shaft of the cooling fan.

When the cooling load of the cooling device is small, the switching means switches to the second path to guide the pressure oil discharged from the hydraulic pump to the first hydraulic motor and the second hydraulic motor separately. At this time, the distribution of pressure oil to both motors is adjusted by the adjustment means. Through the above steps, the refrigerant compressor is rotated at low speed.

At this time, in the conventional device, the second hydraulic motor is driven by the pressure oil that bypassed the first hydraulic motor, so the energy of the pressure oil is effectively used without wasting the pressure oil discharged from the hydraulic pump. Use it for.

[Effects of the Invention] Energy loss of the pressure oil discharged from the hydraulic pump can be reduced.

[Embodiment] A hydraulic drive system for a vehicle according to the present invention will be explained based on an embodiment shown in FIGS. 1 to 5. Figure 1 shows an automobile hydraulic drive system that adopts the present invention. The automobile hydraulic drive device 1 includes a hydraulic pump 2, a first hydraulic motor 3, a second hydraulic motor 4, a third hydraulic motor 5, a power steering device 6, and a hydraulic circuit 7.

The hydraulic pump 2 is rotationally driven by the engine 21, pumps up hydraulic oil in the oil tank 22, and pumps the hydraulic oil so that it circulates within the hydraulic circuit 7.

The first hydraulic motor 3 is connected to a drive shaft of a refrigerant compressor 32 built into the cooling device 31, and is rotationally driven by pressure oil discharged from the hydraulic pump 2. The second hydraulic motor 4 is
Cooling fan 4 blowing air to a radiator (not shown)
The first hydraulic motor 2 is connected to the first drive shaft, and is rotationally driven by the pressure oil discharged from the hydraulic pump 2, like the first hydraulic motor 3. As shown in FIG. 4, the second hydraulic motor 4 changes the rotational speed N of the cooling fan 41 in accordance with the drive oil pressure (differential pressure across the front and back) ΔPt of the second hydraulic motor 4. Third hydraulic motor 5
is connected to the drive shaft of the alternator 51, and similarly to the first hydraulic motor 3, is rotationally driven by the pressure oil discharged from the hydraulic bomb 2. The power steering device 6 has a known structure and uses hydraulic pressure to reduce the steering force of the driver.

The hydraulic circuit 7 has pressure oil passages 70 to 79.

The pressure oil passage 70 transports the hydraulic oil pumped up from the oil tank 22 by the operation of the hydraulic pump 2 through the hydraulic bomb 2, the capacity control valve 81, and the third hydraulic motor 5.
, 72, 73. The pressure oil flow path 71 is a flow path that guides the pressure oil that has flowed in from the pressure oil flow path 70 to the flow path switching valve 82 via the first hydraulic motor 3 .

The pressure oil flow path 72 is a flow path that branches off from the pressure oil flow path 71 at a branch point a and guides the flow of pressure oil to the flow path switching valve 82 via the variable throttle valve 83 . The pressure oil passage 73 supplies the pressure oil flowing from the pressure oil passage 70 to the first hydraulic motor 3 and the second hydraulic motor 4.
This is a flow path that detours and leads to the power steering priority valve 84. The pressure oil flow path 74 is a flow path that guides the pressure oil flowing in from the flow path switching valve 82 to the collection point b. The pressure oil passage 75 is connected to the passage switching valve 8
The pressure oil flowing from 2 is passed through the second hydraulic motor 4 to the gathering point b.
It is a flow path that leads to. The pressure oil flow path 76 is a flow path that causes the pressure oil branched from the pressure oil flow path 75 to bypass the second hydraulic motor 4 and leads to the collection point b via the flow rate control valve 85. Pressure oil flow path 7
7 is a power steering priority valve 84 for the pressure oil flowing in from the gathering point b.
It is a flow path that leads to. The pressure oil passage 78 is connected to the power steering priority valve 8
This is a flow path that guides the pressure oil flowing in from 4 to the power steering device 6. The pressure oil flow path 79 is a flow path that guides the pressure oil flowing from the power steering device 6 to the oil tank 22 via the oil cooler 86. Further, the hydraulic circuit 7 has two paths defined by pressure oil channels 71, 72, 74-76. A first path 8 connects the first hydraulic motor and the second hydraulic motor in series, and a second path connects the first hydraulic motor 3 and the second hydraulic motor 4 in parallel.
This is route 9.

The first path 8 is switched by a flow path switching valve 82 to transfer the pressure oil flowing from the pressure oil flow path 70 to the pressure oil flow path 71 at a branch point a.
75 and 76, and flows out to the pressure oil passage 77 at the collection point b. The second path 9 is switched by the flow path switching valve 82, and the
One path 91 passing through the hydraulic motor 3 and the second hydraulic motor 4
and the other route 92 passing through. One route 91 is
The pressure oil flowing from the pressure oil flow path 70 at the branch point a is transferred to the pressure oil flow path 7.
1.74 and flows out to the pressure oil flow path 71 at the collection point b. The other path 92 is a path in which the pressure oil that flows from the pressure oil flow path 70 at the branch point a flows out into the pressure oil flow path 77 at the collection point b via the pressure oil flow paths 72, 75, and 76.

The capacity control valve 81 is a valve that controls the discharge amount of the hydraulic pump 2 by changing its opening depending on the amount of current supplied.

The flow path switching valve 82 is part of the switching means of the present invention,
This is a valve that switches between the first path 8 and the second path 9. When the flow path switching valve 82 is energized, it overcomes the spring force of the spring 87 and switches the hydraulic circuit 7 from the l-th path 8 to the second path 9. Further, the flow path switching valve 82 switches the hydraulic circuit 7 from the second path 9 to the first path 8 by the elastic force of the spring 87 when the energization is stopped. The variable throttle valve 83 is an adjusting means of the present invention, and is a valve that adjusts the differential pressure between the branch point a and the gathering point b by changing the degree of opening of the pressure oil flow path 72 according to the amount of energization.

In other words, the variable throttle valve 83 controls the driving pressure ΔPc of the first hydraulic motor 3 and the pressure reduction amount ΔP. The amount of pressure oil flowing into the pressure oil flow path 71 and the amount of pressure oil flowing into the pressure oil flow path 72 are adjusted so that the sum of the drive oil pressure ΔP of the second hydraulic motor 4 becomes equal. Change the amount and distribution. The power steering priority valve 84 is connected to the pressure oil passages 71, 72, 74 to
76 and the pressure oil flow path 73. This power steering priority valve 84 is activated by a spring 89 when the oil pressure in the pressure oil passage 78 increases to a predetermined value or more due to the driver's steering and the pilot pressure in the pressure oil passage 88 increases to a predetermined value or more. Overcoming the spring force, the pressure oil passage 73 is switched so that the pressure oil flows. The flow rate control valve 85 has a valve opening pressure, that is, a second
By changing the drive oil pressure ΔPf of the drive motor 4, the amount of pressure oil flowing into the second hydraulic motor 4 is controlled.

These capacity control valves 8L flow path switching valve 82, variable throttle valve 8
3 and the flow rate control valve 85 are energized and controlled by the control circuit 10. This control circuit 10 is part of the switching means of the present invention, and includes an air conditioning control panel 11, an inside air sensor 12, an outside air sensor 13, a solar radiation sensor 14, and a water temperature sensor 15. The control circuit 10 also includes an internal air sensor 12,
Outside air sensor 13, solar radiation sensor 14, and water temperature sensor 15
The cooling load of the cooling device 31 is calculated based on the electrical signal input from the air conditioner. The air conditioning control panel 11 is a detection means of the present invention, and includes a room temperature setting switch (not shown) that sets the temperature inside the vehicle and a blower switch (not shown) that adjusts the air flow rate of a blower (not shown). ) etc. are arranged. The inside air sensor 12 is a detection means of the present invention, and detects the detected temperature inside the vehicle interior, and sends the detected value to the control circuit 10. The outside air sensor 13 is a detection means of the present invention, and converts the detected temperature outside the vehicle interior into an electrical signal, and sends the electrical signal to the control circuit 10. The solar radiation sensor 14 is a detection means of the present invention, and converts the detected amount of solar radiation into an electrical signal and sends the electrical signal to the control circuit 10. Water temperature sensor 15
converts the detected engine coolant temperature into an electrical signal,
The electrical signal is sent to the control circuit 10. FIG. 2 is a flowchart showing the main operations of the control circuit 10.

First, in step S1, electrical signals are input from the inside air sensor 12, outside air sensor 13, solar radiation sensor 14, and water temperature sensor 15, and setting signals are input from the room temperature setting switch of the air conditioning control panel 11, etc. In step S2, the cooling load of the cooling device 31 is calculated based on each signal input in step S1.

In step S3, it is determined whether the cooling load is large. For example, the required blowing temperature T. . If the temperature is ≦10℃, it is determined that the cooling load is large. In addition, the required blowing temperature T. o is calculated using the following formula. T. .

=K, x'[', -K, XT, -K. XT. , -Kl,XQ. +C T. : Set temperature T1: Vehicle interior temperature T. 1 Vehicle outdoor temperature Q,: Solar radiation K. ,K,. , K. ,K, ,C: constant step S3
If the determination result is YES (cooling load is large), the process advances to step S4, and the flow path switching valve 82 is de-energized (OFF
)do. In step S5, the amount of electricity supplied to the capacity control valve 81 is changed depending on the magnitude of the cooling load.

In step S6, the rotation speed of the cooling fan 41 is controlled according to the size of the cooling load and the engine coolant temperature. In other words, the second
The amount of current supplied to the flow rate control valve 85 is changed so as to change the drive oil pressure ΔP of the hydraulic motor 4.

On the other hand, if the determination result in step S3 is NO (cooling load is small), the process proceeds to step S7, and the flow path switching valve 82 is energized (ON>).

In step S8, similarly to step S6, the amount of current applied to the flow rate control valve 85 is changed so as to change the drive oil pressure ΔPt of the second hydraulic motor 4 according to the size of the cooling load and the engine cooling water temperature.

In step S9, the drive oil pressure ΔPc of the first hydraulic motor 3
The amount of current applied to the variable throttle valve 83 is changed so that the sum of the pressure reduction amount ΔP1 of the variable throttle valve 83 and the drive oil pressure ΔP of the second hydraulic motor 4 becomes equal.

In step S10, the size of the cooling load and the cooling fan 4 are determined.
The amount of current supplied to the capacity control valve 81 is changed depending on the rotation speed N of the engine. That is, the amount of current supplied to the capacity control valve 81 is changed depending on the magnitude of the cooling load and the drive oil pressure ΔPt of the second hydraulic motor 4.

After the control in steps S6 and S10, the process returns to step S1 again to repeat the control.

The operation of the automobile hydraulic drive system 1 of this embodiment will be explained based on FIGS. 1 to 4.

Inside air sensor 12, outside air sensor 13, solar radiation sensor 14, water temperature sensor 15, and air conditioning control panel 11
The cooling load of the cooling system fi31 is calculated based on the signal input from the room temperature setting switch or the like.

If the calculated cooling load is large, the hydraulic circuit 7 is switched to the first path 8 by stopping the energization of the flow path switching valve 82.
Switch to

Therefore, all the pressure oil discharged from the hydraulic pump 2 is guided to the third hydraulic motor 5 and then to the first hydraulic motor 3. Then, the pressure oil flowing out from the first hydraulic motor 3 passes through the flow path switching valve 82 and is passed through the flow control valve 85 to the second
The amount of pressurized oil flowing into the hydraulic motor 4 is controlled. Therefore, the refrigerant compressor 32 is operated at high speed, so that the interior of the vehicle is rapidly cooled by the cooling device 31.

At this time, the rotation speed of the cooling fan 41 is controlled to a predetermined rotation speed depending on the size of the cooling load and the engine coolant temperature. That is, as shown in the graph of FIG. 4, the number of rotations of the cooling fan 41 is determined by applying a predetermined drive oil pressure to the second hydraulic motor 4. Therefore, by controlling the amount of current supplied to the flow rate control valve 85, only a flow amount larger than the amount of pressure oil corresponding to the predetermined drive oil pressure is guided to the pressure oil passage 76 and detoured from the second hydraulic motor 4.

On the other hand, when the cooling load of the cooling device 31 is small, the hydraulic circuit 7 is switched to the second path 9 by energizing the flow path switching valve 82. Therefore, the pressure oil discharged from the hydraulic pump 2 is
After being guided to the hydraulic motor 5, it branches at a branch point a and is guided separately to the first hydraulic motor 3, the second hydraulic motor 4, and the pressure oil passage 76. At this time, by controlling the energization amount of the variable throttle valve 83, the differential pressure between the branch point a and the gathering point b is adjusted, and the amount of pressure oil flowing into the first hydraulic motor 3 and the pressure oil flow path 75 are adjusted. Adjust the distribution with the amount of pressure oil flowing in.

Therefore, since the refrigerant compressor 32 is operated at low speed, the interior of the vehicle is slowly cooled by the air conditioner fi31.

In addition, by increasing the amount of pressure oil flowing into the pressure oil flow path 75, even if the refrigerant compressor 32 is operated at low speed, a sufficient amount of pressure oil is introduced to the power steering device 6 to satisfy the steering feeling. be able to. Further, the amount of current supplied to the capacity control valve 81 is adjusted according to the size of the cooling load and the rotation speed of the cooling fan 41 so that the amount of pressure oil required for the first hydraulic motor 3 and the second hydraulic motor 4 is equal to the total amount. It may be controlled. That is, the amount of pressure oil Qc supplied to the first hydraulic motor 3 and the second
By adjusting the amount of pressure oil Qf supplied to the hydraulic motor 4 as shown in the graph of FIG. 5, the amount of pressure oil flowing through the pressure oil flow path 76 can be adjusted to 04! /sin.

Therefore, energy loss of the pressure oil due to the pressure oil flowing through the pressure oil passage 76 can be eliminated.

Therefore, the energy loss of the pressure oil is caused by the variable throttle valve 83
Only those that occur in Moreover, the energy loss of the pressure oil generated in the variable throttle valve 83 is caused by the pressure difference ΔP between the drive oil pressure ΔPc of the first hydraulic motor 3 and the drive oil pressure ΔP of the second hydraulic motor 4, and the pressure oil in the pressure oil passage 72. Since the energy loss is multiplied by the amount, the energy loss can be significantly smaller than the energy loss in the bypass flow path 108 of the conventional fA.

For example, Q. =
24! /win, drive oil pressure ΔP of the first hydraulic motor 3
c=10MPa, amount of pressure oil Qt required for the second hydraulic motor 4
= 64! /win, drive oil pressure ΔP of the second hydraulic motor 4, = 5 MPa, minimum pressure oil amount Q. of the power steering device 6. =8jl/min.

In this case, in the conventional device A, the discharge amount Qp-
811/sin, discharge pressure P. = 15 MPa, and the loss power L0 is calculated as shown in the following equation.

Lo = {10X(8-21+5X(8-6)l/
60 = 1.2kW On the other hand, in this example, the discharge amount of the hydraulic pump Q, 81/s
in, discharge pressure P. = 10MPa, and the power loss L
．． is calculated as follows.

L, = ((10-5)X 6) /60= 0.
5 kW Therefore, the energy loss of the pressure oil discharged from the hydraulic pump 2 can be significantly reduced.

(Modification) In this embodiment, the first hydraulic motor and the second hydraulic motor are connected in parallel when the cooling load is small, but the first hydraulic motor and the second hydraulic motor are connected in parallel when the refrigerant compressor is started. They may be connected to reduce the surge pressure at startup and lower the maximum oil pressure of the hydraulic drive device. In this method, when the first hydraulic motor and the second hydraulic motor are connected in parallel and the variable throttle valve is gradually throttled, the surge pressure is reduced.

Further, the completion of startup of the refrigerant compressor is determined by a rotation speed sensor of the refrigerant compressor, a refrigerant pressure sensor, or the like.

In this embodiment, the cooling system does not stop operating while the engine is running, but a solenoid valve is provided in the pressure oil passage 71 so that the cooling system stops operating when the operation switch is turned off. Also good.

In this example, the necessary blowout temperature was calculated in order to determine the size of the cooling load, but it can also be determined based on the temperature difference between the vehicle interior temperature and the set temperature, the height of the vehicle exterior temperature, the amount of solar radiation, etc., or a combination of the following. good.

In this embodiment, when the flow path switching valve is energized, the path is switched to the second path, but when the flow path switching valve is energized, the path is switched to the first path.

In this embodiment, the cooling fan is used as a radiator cooling fan, but it may also be used as a cooling fan that blows air to a refrigerant condenser or other heat exchanger of an air conditioner.

[Brief explanation of drawings]

1 to 5 show one embodiment of the present invention. FIG. 1 is a schematic diagram showing a hydraulic drive system for an automobile, and FIG. 2 is a flowchart showing the main operations of the control circuit. Fig. 3 is a graph showing the relationship between the drive oil pressure of the first hydraulic motor and the rotation speed of the refrigerant compressor, and Fig. 4 is a graph showing the relationship between the drive oil pressure of the second hydraulic motor and the rotation speed of the cooling fan. FIG. 5 is a graph showing the relationship between the amount of pressurized oil and the cooling load. FIG. 6 is a schematic diagram showing a conventional device A. In the diagram: 1...Automotive hydraulic drive system 2...Hydraulic pump 3
...First hydraulic motor 4...Second hydraulic motor 7.
...Hydraulic circuit 8...First path 9...Second path
10... Control circuit (switching means) 82... Flow path switching valve (switching means) 83... Variable throttle valve (adjusting means)

Claims (1)

[Claims] 1) (a) a hydraulic pump driven by an engine;
b) a first hydraulic motor connected to a drive shaft of a refrigerant compressor incorporated in the cooling device and driven by pressure oil discharged from the hydraulic pump; and (c) a cooling fan that blows air to the heat exchanger. a second hydraulic motor connected to a drive shaft and driven by pressure oil discharged from the hydraulic pump; (d) the first hydraulic motor and the second hydraulic motor are connected in series to form the hydraulic pump; a first path that guides pressure oil discharged from the first hydraulic motor to the second hydraulic motor; and a first path that connects the first hydraulic motor and the second hydraulic motor in parallel to the hydraulic pump. a hydraulic circuit having a second path that separately guides pressure oil discharged from the first hydraulic motor and the second hydraulic motor; (e) a detection means for detecting a cooling load of the cooling device; (f) switching means for switching between the first path and the second path in accordance with the cooling load detected by the detection means; 2. A hydraulic drive device for a vehicle, comprising: two hydraulic motors; and an adjusting means for adjusting the flow rate distribution of pressure oil guided to the two hydraulic motors.