JPH0518367A - Fluid displacement pump capacity controller - Google Patents

Abstract

(57) [Summary] [Purpose] The pump capacity of a system having a plurality of working fluid supply ports sequentially connected in series is controlled so that excess or deficiency of fluid amount does not occur at all ports. [Structure] The fluid from the pump 11 is first regulated to a first line pressure P _L1 by a regulator valve 15, and the surplus fluid is regulated to a second line pressure P _L2 by a regulator valve 16. Excess fluid from the regulator valve 16 is drained through the orifice 17, and the capacity control cylinder 11 is provided upstream of the orifice.
generating a feedback pressure P _F to _a. This pressure P _F
Is too low, the capacity of the pump 11 is increased, and on the contrary, the capacity of the pump 11 is decreased, and the pump capacity is controlled so that the drain amount from the orifice 17 is kept constant. Therefore, this drain amount is wasted, but ports _12a , 12
_The pump capacity can be controlled so that the flow rate to _b is not excessive or insufficient.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid actuating system used for a shift control hydraulic circuit of an automatic transmission, and more particularly to a device for controlling a pump displacement.

[0002]

2. Description of the Related Art Conventionally, as a shift control hydraulic circuit for an automatic transmission, there is one described in "RE4R01A type automatic transmission maintenance manual" issued by Nissan Motor Co., Ltd., of which the line pressure control system is schematically shown. It is as shown in FIG.

A variable displacement pump 1 discharges hydraulic oil to a line pressure circuit 2. The discharged oil also goes to the pressure regulator valve 3, whereby the pressure is adjusted to a predetermined line pressure P _L and used for shift control of the automatic transmission. Pilot valve
4 produces a constant pilot pressure P _P based on this line pressure P _L , and supplies this to the line pressure solenoid 5 and the pressure modifier valve 6. Line pressure solenoid 5
Is subjected to duty control in accordance with a line pressure control factor to generate a line pressure control pressure from a constant pilot pressure P _p and supply it to the pressure modifier valve 6. The pressure modifier valve 6 responds to this control pressure to generate a corresponding pressure modifier pressure P _M from the pilot pressure P _p , and applies this to the pressure regulator valve 3. The valve 3 regulates the line pressure P _L according to the modifier pressure P _M to a duty ratio of the solenoid 5, that is, a predetermined value corresponding to the calculation result.

The pressure regulator valve 3 further supplies a part of the hydraulic oil from the pump 1 to the torque converter via the circuit 7 for its operation, and the torque converter relief valve 8 provides a predetermined pressure P _T inside the torque converter. To The pressure regulator valve 3 drains excess oil through the orifice 9, and contributes to the displacement control of the pump 1 by using the pressure P _F generated upstream of the orifice 9 according to the amount of excess oil as the pump feedback pressure. Thereby, the capacity of the pump 1 is controlled so that the amount of surplus oil drained through the orifice 9 becomes a predetermined value.

[0005]

In such a fluid actuating system, however, the pump 1 is displacement-controlled so that the line pressure P _L is not insufficient to bring it to a predetermined value. There is no compensation that the pressure P _T is just enough to bring it to a predetermined value. Therefore, conventionally,
The torque converter pressure P _T may fall below a predetermined value due to insufficient pump capacity, or the drive energy of the pump 1 may be unnecessarily increased due to excessive pump capacity to deteriorate the fuel amount of the engine that drives this pump. there were.

An object of the present invention is to make it possible to appropriately control the pump displacement even when there are a plurality of fluid actuation systems.

[0007]

To this end, the present invention provides a downstream working fluid in a fluid working system having a plurality of working fluid supply ports for supplying working fluid from a pump to a fluid working element in series. The capacity of the pump is controlled according to the state quantity of the fluid at the supply port. In the case where the fluid from the most downstream working fluid supply port is regulated and output by a regulator valve, the amount of surplus fluid from this regulator valve is used as the state quantity of the fluid, or regulated by the regulator valve. The applied pressure can be used as the state quantity of the fluid.
Further, in the case where the fluid from the most downstream working fluid supply port is output as it is without pressure adjustment, the working fluid supply amount from the port can be used as the state quantity of the fluid. In any of the above cases, when there are a plurality of pumps, it is preferable to appropriately unload any pump to control the capacity.

[0008]

The working fluid from the pump is sequentially supplied in series to the corresponding fluid working elements through a plurality of working fluid supply ports provided in the fluid working system to fluidly actuate these elements. At this time, the capacity of the pump is controlled according to the state quantity of the fluid in the working fluid supply port on the most downstream side.
Therefore, regardless of whether each fluid actuating element is operated by pressure or flow rate, the capacity of the pump is controlled so that there is no excess or deficiency for the operation of all elements, and the fluid operation due to insufficient pump capacity. It may interfere with the operation of the element,
It is possible to prevent the pump drive load from unnecessarily increasing due to an excessive pump capacity. When the innermost pressure of the working fluid supply port is regulated by the regulator valve and the fluid actuating element is actuated by this regulated fluid, the surplus fluid amount from the regulator valve and the pressure regulated by the regulator valve are used. Expresses the excess and deficiency of the pump capacity well, and it is practical to use these as the state quantities of the fluid for controlling the pump capacity, so that suitable pump capacity control can be realized. On the other hand, the working fluid supply port on the most downstream side supplies the fluid whose pressure is not adjusted to the operation of the fluid working element as it is,
When this operation is controlled by the flow rate of the fluid, it is practical to set the flow rate as the state quantity of the fluid for controlling the pump capacity, and suitable pump capacity control can be realized. In any of the above cases, in the case where there are a plurality of pumps, if the capacity is controlled by appropriately unloading any pump, it is not necessary to use an expensive variable capacity pump. It is advantageous in cost.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the device of the present invention, in which 11 is a variable displacement pump, which supplies a working fluid discharged from the variable pump to a main circuit 12. Sequential hydraulic oil supply ports 12 _a and 12 _b are set in the main circuit 12, and the sub-circuit 1
A fluid actuating element (not shown) is connected via 3, 14.
Port 12 _a, 12 _b between the interposed first regulator valve 15 in the main circuit 12 in the second regulator valve 16 and orifice 17 are sequentially inserted into the main circuit 12 downstream of the port 12 _b, downstream of the orifice 17 At, the main circuit 12 is drained.

The first regulator valve 15 adjusts the inside of the sub-circuit 13 to a predetermined first line pressure P _L1 in response to the line pressure control pressure P _S (which may be an electric control force), and this first line A corresponding element (for example, a secondary pulley of a V-belt type continuously variable transmission) is hydraulically operated by pressure. Further, the second regulator valve 16 sets a constant second line pressure P _L2 in the sub-circuit 14 according to the spring force of the built-in spring, and the corresponding element (for example, forward / reverse switching clutch of V-belt type continuously variable transmission). To
Operates by fluid. The second regulator valve 16 can also be configured so that the line pressure P _L2 can be changed by a control force from the outside like the first regulator valve 15. Further, the main circuit 12 is connected between the second regulator valve 16 and the orifice 17 by the feedback circuit 18 to the displacement control piston 11 _a of the pump 11.

The operation of the above embodiment will be described below. The working fluid from the pump 1 is first regulated to the first line pressure P _L1 by the first regulator valve 15, reaches the corresponding fluid working element from the sub-circuit 13, and the surplus fluid flows into the sub-circuit 14. The second regulator valve 14 enables the operation of the corresponding element by setting the second line pressure P _{L2 in} the sub-circuit 14, and drains the excess fluid through the orifice 17. The orifice 17 produces a feedback pressure P _F according to the amount of drain due to the throttling effect, and the feedback cylinder 11
supplied to _a.

When the feedback pressure P _F is higher than the set value, the pump 11 has a smaller capacity and reduces the discharge amount, and when the feedback pressure P _F is lower than the set value, the pump 11 has a large capacity and the discharge amount increases. Thus, the pump 11 is capacity-controlled so that the feedback pressure P _F is maintained at the set value, that is, the drain amount passing through the orifice 17 becomes a constant amount determined by the inner diameter of the orifice 17. Moreover, the drain fluid is the line pressure P _L1 , P _L due to the regulator valves 15 and 16.
_Since it is the fluid after the pressure adjustment of _L2 , these line pressures P _L1 and P _L2 are set to predetermined values, which results in that the displacement control of the pump is performed after satisfying this condition. Thus the capacity of the pump 11, even a plurality working fluid supply port 12 _a, 12 _b is controlled so as not to cause excess and deficiency of the amount of fluid to all these ports, it results in lack of fluid volume at a certain port It is possible to prevent problems such as incomplete operation of the corresponding element and an increase in pump drive load due to excessive pump discharge.

If the second regulator valve 16 is replaced by the type shown in FIG. 2 instead of the one shown in FIG. 1, the drain portion via the orifice 17 in FIG. 1 is not necessary at all. The second regulator valve 16 in FIG. 2 normally drains the feedback cylinder 11 _a to increase the capacity of the pump 11, and when the second line pressure P _L2 reaches a certain value determined by the built-in spring, this line pressure is fed back to the feedback pressure P L.
Were supplied to a cylinder 11 _a as _F, intended to reduce the capacity of the pump 11, it is possible to a similar volume control as in FIG. In the example of FIG. 2, the drain of the hydraulic oil is not required for the capacity control, so that the efficiency of the pump 11 can be further increased.

[0014] Figure 3 shows another example of the present invention, port 12 a feedback circuit 18 to the cylinder 11 _a in this example
_It is connected to _b and is configured to supply the second line pressure P _L2 as it is to the cylinder 11 _a as the feedback pressure P _F. In this case, the excess fluid after adjusting the first line pressure P _L1 by the first regulator valve 15 has a constant second line pressure P _L2.
Until it becomes, the cylinder 11 _a , which receives this, increases the capacity of the pump 11 to increase the second line pressure P _L2 . When the second line pressure P _L2 reaches the set value and then becomes higher than that, the cylinder 11 _a reduces the displacement of the pump 11 to keep the second line pressure P _L2 at a predetermined constant value.
The second line pressure P _L2 can be made variable in accordance with the electromagnetic force F by adding and controlling the electromagnetic force F in the direction that assists the cylinder 11 _a or in the direction opposite thereto.
Further, in this example, a relief circuit 20 having a relief valve 19 for preventing the second line pressure P _L2 from exceeding a set value for safety.
The better to connect to port 20 _b.

FIG. 4 shows an example in which the capacity control of FIG. 3 is performed electronically. For this purpose, in this example, the second line pressure P _L2 is detected by the pressure sensor 21, and the detected value is fed back as a feedback signal. Electronic capacity control unit 22 as S _F
To enter. This unit 22 outputs the second signal from the input signal S _F.
Depending on whether the line pressure P _L2 is higher or lower than the set value, the electromagnetic displacement control actuator 11 _b of the pump 11 is driven to perform the same displacement control as in FIG.

FIG. 5 shows still another example of the present invention, in which the sub-circuit 13 is a system in which the elements are fluid-operated at the first line pressure P _L1 as in the above-mentioned respective embodiments, and the sub-circuit 14 does this. A system for controlling the operation of the corresponding element according to the amount Q ₂ of the working fluid flowing therethrough. In this case, the orifice 2 in the subcircuit 14
3 is inserted, and a flow rate feedback valve 24 which is operated at a differential pressure according to the flow rate Q ₂ generated before and after that is provided. However, this valve 24, when the differential pressure of less than the flow rate Q ₂ is set value orifice 23 is low, to increase the capacity of the pump 11 the cylinder 11 _a and the drain, the flow rate Q ₂ is more than the set value orifice When the differential pressure across 23 is high, the cylinder 11
shall by supplying pressure port 12 _b to _a to reduce the capacity of the pump 11.

The operation of this example is as follows. The first line pressure P _L1 is controlled by the regulator valve 15 in the same manner as in each of the above-described examples, and excess fluid is supplied from the regulator valve 15 to the sub-circuit 1
Via 4 to actuate the corresponding elements. Here, if the fluid amount Q ₂ of the circuit 14 does not reach the set value, the valve 24 drains the cylinder 11 _a to increase the capacity of the pump 11,
This increases the flow rate Q ₂ . On the contrary, when the fluid amount Q ₂ exceeds the set value, the valve 24 causes the cylinder 11 _a to _move to the port 1
The pressure of 2 _b is supplied to reduce the capacity of the pump 11, which reduces the flow rate Q ₂ . Thus, the capacity of the pump 11 is controlled so that the flow rate Q ₂ is maintained at the set value, and this capacity control is performed with the first line pressure P _L1 adjusted to a predetermined value. Ports _12a and _12b
The pump capacity can be controlled so that an excess or deficiency of the amount of fluid to the pump does not occur. If, for example, an electromagnetic force other than the differential pressure across the orifice 23 and a built-in spring is applied to the flow rate feedback valve 24 to control it, the fluid amount Q ₂ can be adjusted to the set value by adjusting the electromagnetic force. It can be made variable without limitation.

FIG. 6 shows an embodiment in which the capacity of the pump can be controlled by another method in the example of FIG. 3, and this method can of course be used in an example other than FIG. In FIG. 6, the pump 11 is not of a variable displacement type, but instead, another similar fixed displacement pump 25 is added in parallel. Then, a displacement control valve 26 is inserted into the discharge circuit of the pump 25, and the valve 26 receives the second line pressure P _L2 as the feedback pressure P _F and responds to this. That is, if the second line pressure P _L2 is less than the set value, the valve 26 opens the discharge circuit of the pump 25 to add the discharge fluid from the pump 25 to the discharge fluid from the pump 11 to increase the overall pump capacity. By increasing the pressure, the second line pressure P _L2 is increased toward the set value. On the other hand, when the second line pressure P _L2 exceeds the set value, the valve 26 shuts off the discharge pressure circuit of the pump 25 and unloads the pump 25 by draining the entire amount of discharge fluid to reduce the overall pump capacity. As a result, the second line pressure P _L2 is reduced toward the set value. With this action, the same action and effect as described above with reference to FIG. 3 are achieved in this example as well. If the capacity control valve 27 of FIG. 7 is used instead of the capacity control valve 26 of FIG. 6, this valve 27 has a hysteresis circuit 28 and the second line pressure P _L2 is in a valve state in which the pump 25 is in an unloading state. Since the circuit 28 acts on the valve 27 as a hysteresis pressure, the pump 2
Hysteresis can be set between the setting switching pressure in the normal state where the discharge circuit of No. 5 is opened and the unloading state where the discharge circuit is closed.

Here, the function and effect common to the embodiments of FIGS. 2 to 7 will be supplementarily described. In the conventional structure shown in FIG. 8, since the capacity of the pump 1 is controlled according to the pressure generated by draining the hydraulic oil through the orifice 7 upstream of the orifice 7, if the inner diameter of the orifice 9 is small, the orifice upstream with respect to the change in the pump capacity is affected. The pressure change, that is, the feedback gain is too large, and the control becomes unstable. Therefore, the inner diameter of the orifice 9 must be increased, and the drain amount passing through the orifice 9 is large correspondingly. Therefore, it is necessary to increase the capacity of the pump 1 in consideration of this drain amount, which causes an increase in pump driving energy. . However, in the embodiments of FIGS. 2 to 7, the above-mentioned problem can be avoided because the drain orifice as described above is not required for controlling the pump displacement.

[0020]

As described above, the pump displacement control apparatus according to the present invention responds to the state quantity of the fluid at the most downstream port of the plurality of working fluid supply ports which are sequentially set in series with the fluid working system. Since the pump capacity is controlled, the pump capacity is controlled in a manner that does not cause excess or deficiency in the flow rate of all working fluid supply ports, and the insufficient capacity hinders the operation of the element related to a certain port. It is possible to prevent the pump drive energy from being unnecessarily increased due to an excessive capacity. Further, in the case where the innermost pressure is regulated by the regulator valve in the most downstream port, the excess fluid amount from the regulator valve or the pressure regulated by the regulator valve is controlled by the pump displacement control as in claim 2 or 3. Suitable control is realized by using the state quantity of the fluid for use in capacity control.

Further, in the case where the most downstream port supplies a fluid whose pressure is not regulated to the fluid actuating element and the operation thereof is controlled by the flow rate, this flow rate is used for controlling the pump displacement. Suitable control is realized by using the state quantity of the fluid for capacity control. In any of the above cases, if there is a plurality of pumps, the capacity can be changed by appropriately unloading any of the pumps as described in claim 5, thereby increasing the expensive capacity. There is no need to use a variable pump, which is cost effective.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a capacity control device of the present invention.

FIG. 2 is a system diagram showing a modified example of FIG.

FIG. 3 is a system diagram showing another example of the present invention.

FIG. 4 is a system diagram of an example in which the example of FIG. 3 is electronically controlled.

FIG. 5 is a system diagram showing still another example of the present invention.

FIG. 6 is a system diagram showing an example in which the example of FIG. 3 is configured to have a plurality of pumps, and in this configuration, the capacity of the pumps can be controlled.

FIG. 7 is a schematic diagram showing another example of the displacement control valve in the same example.

FIG. 8 is a system diagram showing a conventional pump displacement control device.

[Explanation of symbols]

11 Pump 12 Main circuit 12 _a Working fluid supply port 12 _b Working fluid supply port 13 Sub circuit 14 Sub circuit 15 First regulator valve 16 Second regulator valve 17 Orifice 18 Feedback circuit 19 Relief valve 20 Relief circuit 21 Pressure sensor 22 Electronic type Capacity control unit 23 Orifice 24 Flow rate feedback valve 25 Pump 26 Capacity control valve 27 Capacity control valve 28 Hysteresis circuit

Claims (5)

[Claims] 1. A fluid working system having a plurality of working fluid supply ports for supplying a working fluid from a pump to a fluid working element in series in sequence, wherein the pump is operated in accordance with the state quantity of the fluid at the most downstream working fluid supply port. A pump displacement control device for a fluid actuating system, which is configured to control displacement. 2. When the fluid from the most downstream working fluid supply port is pressure-controlled by a regulator valve and output, the excess fluid amount from the regulator valve is set as the state amount of the fluid. A pump displacement control device for a fluid actuation system, characterized in that 3. The pressure control device according to claim 1, wherein when the fluid from the most downstream working fluid supply port is regulated by a regulator valve and output, the pressure regulated by the regulator valve is used as the state quantity of the fluid. A pump displacement control device for a fluid actuation system, characterized in that 4. The method according to claim 1, wherein when the fluid from the most downstream working fluid supply port is output without pressure adjustment,
A pump displacement control device for a fluid working system, wherein a working fluid supply amount from the port is set as a state quantity of the fluid. 5. The fluid working system according to claim 1, wherein when a plurality of pumps are present, the capacity is controlled by appropriately unloading an arbitrary pump. Pump capacity control device.