JP2830525B2 - Pump displacement control device for fluid working system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

[0005] Reference numeral 1 denotes a variable displacement pump which discharges hydraulic oil to a line pressure circuit 2. Discharge oil toward to the pressure regulator valve 3, pressurized thereby regulated to a predetermined line pressure P _L is used to shift control of the automatic transmission. Pilot valve
4 produces a constant pilot pressure P _P based on the line pressure P _L, and supplies it to the line pressure solenoid 5 and the pressure modifier valve 6. Line pressure solenoid 5
Is duty controlled according to the line pressure control factor supplied to the pressure modifier valve 6 creating a line pressure control pressure from the constant pilot pressure P _p. Pressure modifier valve 6 creates a pressure modifier pressure P _M corresponding from the pilot pressure P _p in response to the control pressure, applies it to the pressure regulator valve 3. The valve 3 is a duty ratio of the solenoid 5 to line pressure P _L depending on the modifier pressure P _M, i.e. pressure adjusted to 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 a torque converter via a circuit 7 for the operation thereof, and a torque converter relief valve 8 controls a predetermined pressure P _T in the torque converter. To The pressure regulator valve 3 surplus oil drained through the orifice 9, contributes to the capacity control of the pump 1 the pressure P _F generated upstream of the orifice 9 depending on the excess amount of oil as a pump feedback pressure. Thereby, the capacity of the pump 1 is controlled such that the amount of excess oil drained through the orifice 9 becomes a predetermined value.

[0005]

However, in such a fluid working system, the pump 1 is controlled in capacity so that there is no shortage for setting the line pressure P _L to a predetermined value. There is no compensation that the pressure P _T is set to a predetermined value without any excess or deficiency. For this reason, conventionally,
Insufficient pump capacity may cause the torque converter pressure _PT to become less than a predetermined value, or excessive pump capacity may wastefully increase the driving energy of the pump 1 and deteriorate the fuel quantity of the engine that drives the pump. there were.

[0006] It is an object of the present invention to be able to appropriately control the pump displacement even when there are a plurality of fluid working systems.

[0007]

SUMMARY OF THE INVENTION For this purpose, a pump displacement control device for a fluid actuation system according to the present invention comprises a fluid actuation system for actuating a plurality of fluid actuation elements with actuation fluid from a pump. A plurality of working fluid supply ports for supplying a working fluid to the individual fluid working elements are sequentially provided in series, and the working fluid pressure from the working fluid supply port at the most upstream to the corresponding fluid working element is adjusted to a predetermined value, A first regulator valve for sequentially directing the surplus fluid after pressure regulation to the downstream working fluid supply port is provided, and the capacity of the pump is controlled only in accordance with the state quantity of the fluid in the most downstream working fluid supply port. It is characterized by having done. In the case where the fluid from the most downstream working fluid supply port is regulated by the most downstream regulator valve and directed to the corresponding fluid working element, the amount of surplus fluid from the regulator valve after the pressure regulation is determined by the aforementioned method. The state quantity of the fluid or the pressure adjusted by the regulator valve can be used as the state quantity of the fluid. Further, in the one in which the fluid from the most downstream working fluid supply port is directed to the corresponding fluid working element without pressure regulation, the supply amount of the working fluid from the port to the corresponding fluid working element is controlled by the fluid. State quantity. In any of the above cases, when a plurality of the pumps are present, it is preferable to control the capacity by appropriately setting an arbitrary pump to an unload state.

[0008]

The working fluid from the pump is supplied to corresponding fluid working elements via a plurality of working fluid supply ports provided in the fluid working system arranged in series in order, and these elements are fluid-operated. At this time, the working fluid pressure from the working fluid supply port at the uppermost stream to the corresponding fluid working element is regulated to a predetermined value by the first regulator valve, and the excess fluid after the pressure regulation from the first regulator valve is performed. Sequentially go to the downstream working fluid supply port. The displacement of the pump is controlled only in accordance with the state quantity of the fluid at the most downstream working fluid supply port. Thus, regardless of whether each fluid actuation element is actuated by pressure or by flow,
The capacity of the pump is controlled so that there is no excess or deficiency in the operation of all the elements, and it is possible to prevent the operation of the fluid operating element from being inadequate due to the insufficient pump capacity, and to prevent the pump driving load from becoming uselessly large due to the excessive pump capacity. be able to. When the innermost pressure of the working fluid supply port at the most downstream is regulated by a regulator valve and the fluid working element is operated by the regulated fluid, the amount of surplus fluid from the regulator valve and the pressure regulated by the regulator valve are adjusted. Represent well the excess and deficiency of the pump capacity, and it is practical to use these as the state quantities of the fluid for controlling the pump capacity, thereby realizing a suitable pump capacity control. On the other hand, the lowest downstream working fluid supply port directly supplies the fluid whose pressure is not adjusted to the operation of the fluid working element, and in the case where the operation is controlled by the flow rate of the fluid, the flow rate is used for controlling the pump capacity. It is possible to realize a pump displacement control which is practical and suitable for the state quantity of the fluid. In any of the above cases,
In the case where there are a plurality of pumps, if the capacity is controlled by appropriately setting an arbitrary pump in an unloaded state, it is not necessary to use an expensive variable capacity pump, which is advantageous in cost.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an embodiment of the apparatus according to the present invention. Reference numeral 11 denotes a variable displacement pump, which supplies a working fluid discharged from the pump to a main circuit 12. Set the sequential working oil supply port 12 _a, 12 _b in the main circuit 12, the sub-circuits 1 to these
The fluid working elements, not shown, are 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 The main circuit 12 is drained at.

The first regulator valve 15 responds to the line pressure control pressure P _S (which may be an electrical control force) to regulate the pressure in the sub-circuit 13 to a predetermined first line pressure P _L1, and The corresponding element (for example, the secondary pulley of the V-belt type continuously variable transmission) is hydraulically operated by the pressure. The second regulator valve 16 sets the inside of the sub-circuit 14 to a constant second line pressure P _L2 corresponding to the spring force of the built-in spring, thereby using a corresponding element (for example, a forward / reverse switching clutch of a V-belt type continuously variable transmission). To
Fluid operated. Note that the second regulator valve 16 can also be configured such that the line pressure P _L2 can be changed by an external control force, similarly to the first regulator valve 15. The main circuit 12 is connected between the second regulator valve 16 and the orifice 17 to the displacement control piston 11 _a of the pump 11 by the feedback circuit 18.

The operation of the above embodiment will now be described. The working fluid from the pump 1 is first adjusted 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 excess fluid flows into the sub-circuit 14. The second regulator valve 14 enables operation of the corresponding element in the sub-circuit 14 as a second line pressure P _L2 , and drains excess fluid through the orifice 17. The orifice 17 is caused a feedback pressure P _F according to the amount of drainage by the diaphragm effect feedback cylinder 11
supplied to _a.

[0012] When the pump 11 is feedback pressure P _F is higher than the set value, reducing the discharge amount is small capacitance, when the feedback pressure P _F is lower than the set value, to increase the discharge amount is large capacitance. And thus, the pump 11 is such that the feedback pressure P _F is maintained at the set value, i.e. drainage rate through the orifice 17 is capacitively controlled to be a fixed amount determined by the inner diameter of the orifice 17. Moreover, the drain fluid is supplied to the line pressures P _L1 , P _L by the regulator valves 15, 16.
_Since the fluid is the fluid after the pressure regulation of _L2 , these line pressures P _L1 and P _L2 are set to predetermined values, which results in that the displacement of the pump is controlled after satisfying these conditions. 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 Problems such as incomplete operation of the corresponding element and an increase in pump driving load due to an excessive pump discharge amount can be prevented.

If the second regulator valve 16 is replaced with 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 required at all. The second regulator valve 16 in Figure 2 to increase the capacity of the pump 11 normally feedback cylinder 11 _a and the drain, the second line pressure P _L2 is the line pressure feedback pressure P when it reaches a constant value determined by the internal spring
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 drainage of the hydraulic oil is not required for the capacity control, so that the efficiency of the pump 11 can be further increased.

FIG. 3 shows another embodiment of the present invention. In this embodiment, a feedback circuit 18 to _a cylinder 11a is connected to a port 12
connected to _b, it is configured to supply to the cylinder 11 _a second line pressure P _L2 as a feedback pressure P _F as it is. In this case, the surplus fluid after the pressure regulation of the first line pressure P _L1 by the first regulator valve 15 is reduced to a constant second line pressure P _L2.
In until the cylinder 11 _a to be inputted to this raises the second line pressure P _L2 by increasing the capacity of the pump 11. The second line pressure P _L2 becomes the set value, when thereafter to become a greater and cylinder 11 _a keeps the second line pressure P _L2 to reduce the capacity of the pump 11 to 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 an electromagnetic force F in a direction that assists the cylinder 11 _a or in a direction opposite thereto.
Further, in this embodiment, a relief circuit 20 having a relief valve 19 for preventing the second line pressure P _L2 from exceeding a set value for safety.
_Should be connected to port 20b.

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 used as a feedback signal. electronic volume control unit as S _F 22
To enter. The unit 22 is second from the input signal S _F
Depending on whether the line pressure P _L2 is higher or lower than the set value, the same capacity control as in FIG. 3 by driving the electromagnetic displacement control actuator 11 _b of the pump 11.

FIG. 5 shows still another embodiment of the present invention. The sub-circuit 13 is a system in which elements are fluid-operated at the first line pressure P _L1 as in the above-described embodiments. after a system for controlling operation of the corresponding elements according to the working fluid amount Q ₂ to which flows. In this case, the orifice 2
3 is provided, and a flow rate feedback valve 24 is provided which is operated at a differential pressure corresponding to the flow rate Q ₂ generated before and after the flow rate control valve 3. 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, cylinder 11
shall by supplying pressure port 12 _b to _a to reduce the capacity of the pump 11.

The operation of this embodiment 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 embodiments.
Via 4 the corresponding element is actuated. Here, if the fluid amount Q ₂ of the circuit 14 was not yet the set value, the valve 24 will increase the capacity of the pump 11 to drain the cylinder 11 _a,
Thereby increasing the flow rate Q _2. Conversely, when the fluid amount Q ₂ exceeds the set value, the valve 24 is connected to the cylinder 11 _a by the port 1.
Supplying a pressure of 2 _b so as to reduce the capacity of the pump 11, thereby reducing the flow rate Q _2. And thus, the flow rate Q ₂ is made displacement control of the pump 11 so as to be maintained at a set value, since it is done in a state the volume control is that by regulating the first line pressure P _L1 to a predetermined value, also in this embodiment all Ports _12a and _12b
The pump capacity can be controlled so that the amount of fluid to the pump does not become excessive or insufficient. Incidentally, by adding for example an electromagnetic force other than the differential pressure and the internal spring of the orifice 23 to the flow feedback valve 24, if configured to control this fluid quantity Q ₂ by the degree of the electromagnetic force in the setting value It can be variable without limitation.

FIG. 6 shows an embodiment in which the displacement of the pump can be controlled by another method in the example of FIG. 3, and this method can of course be used in examples other than FIG. In FIG. 6, the pump 11 is not of the variable displacement type, and another similar fixed displacement pump 25 is added in parallel instead. Then, insert the volume control valve 26 in the discharge circuit of the pump 25, the valve 26 is input to the second line pressure P _L2 as a feedback pressure P _F, shall be responsive thereto. That is, when the second line pressure P _L2 is less than the set value, the valve 26 opens the discharge circuit of the pump 25 and adds the discharge fluid from the pump 25 to the discharge fluid from the pump 11 to reduce the overall pump capacity. The second line pressure P _L2 is increased toward the set value. Conversely, 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 the pump 25 is unloaded by draining the entire amount of the discharge fluid to reduce the overall pump capacity. Thereby, the second line pressure P _L2 is decreased toward the set value. With this operation, the same operation and effect as described above with reference to FIG. If the displacement control valve 27 of FIG. 7 is used instead of the displacement control valve 26 of FIG. 6, the valve 27 has a hysteresis circuit 28 and the second line pressure P _L2 is in a valve state where the pump 25 is unloaded. Since the circuit 28 acts on the valve 27 as a hysteresis pressure, the pump 2
Hysteresis can be set between the set switching pressure in the normal state in which the discharge circuit 5 is opened and the unload state in which the discharge circuit is closed.

Here, the operation and effect common to the embodiment 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 a change in the pump capacity is changed. The pressure change, that is, the feedback gain is too large, and the control becomes unstable. For this reason, the inner diameter of the orifice 9 must be increased, and the amount of drain passing through the orifice 9 is correspondingly large, and it is necessary to increase the capacity of the pump 1 in anticipation of this amount of drain, which causes an increase in pump driving energy. . However, in the embodiment of FIGS. 2 to 7, the above-mentioned problem can be avoided because the above-described drain orifice is not required at all for controlling the pump displacement.

[0020]

Thus, the pump displacement control apparatus of the present invention has a port for supplying a working fluid from a pump to a plurality of fluid working elements arranged in series with a fluid working system, and a pump for controlling the most upstream flow. The excess fluid after pressure adjustment from the first regulator valve for adjusting the working fluid pressure of the working fluid supply port to a predetermined value is sequentially directed to the downstream working fluid supply port, and only the state quantity of the fluid at the most downstream port is provided. , The pump capacity can be controlled in such a manner that all the working fluid supply ports do not cause excess or deficiency in the flow rate. Operation may be affected,
Excessive pump driving energy due to excessive capacity can be avoided. Further, in the case where the most downstream port regulates the internal pressure by the regulator valve, the surplus fluid amount from the regulator valve as described in claim 2 or 3 is used.
Alternatively, suitable control is realized by using the pressure regulated by the regulator valve as a state quantity of the fluid for controlling the pump displacement for displacement control.

Further, in a system in which the most downstream port supplies unregulated fluid to the fluid operating element and controls its operation by a flow rate, the flow rate is used for controlling a pump displacement. Suitable control is realized by using the state quantity of the fluid for capacity control. In any of the above cases, in the case where a plurality of pumps are present, an expensive pump can be provided by changing the capacity by appropriately unloading any pump as described in claim 5. There is no need to use a variable pump, which is cost-effective.

[Brief description of the 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 modification 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 embodiment in which the example of FIG. 3 has a configuration having a plurality of pumps, and in this configuration, the capacity of the pump can be controlled;

FIG. 7 is a schematic diagram showing another example of the capacity 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)

(57) [Claims] 1. A fluid working system for fluidly operating a plurality of fluid working elements with a working fluid from a pump, wherein a plurality of working fluid supply ports for supplying working fluid from the pump to the individual fluid working elements are sequentially connected in series. A first regulator that regulates a working fluid pressure from a most upstream working fluid supply port to a corresponding fluid working element to a predetermined value, and sequentially directs excess fluid after pressure regulation to a downstream working fluid supply port. A pump displacement control device for a fluid actuation system, characterized in that a valve is provided, and the displacement of the pump is controlled only in accordance with the state quantity of the fluid at the most downstream working fluid supply port. 2. The method according to claim 1, wherein when the pressure from the most downstream working fluid supply port is regulated by a most downstream regulator valve to a corresponding fluid working element, the pressure from the regulator valve after the pressure regulation is adjusted. A pump displacement control device for a fluid working system, wherein the amount of surplus fluid is set as the state quantity of the fluid. 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 most downstream regulator valve and directed to a corresponding fluid working element, the pressure adjusted by the regulator valve is reduced. A pump displacement control device for a fluid operating system, wherein the state quantity of the fluid is set. 4. The hydraulic fluid supply device according to claim 1, wherein when the fluid from the downstreammost hydraulic fluid supply port is directed to the corresponding fluid operation element without pressure regulation, the fluid is supplied from the port to the corresponding fluid operation element. A pump displacement control device for a fluid working system, wherein the amount is a state quantity of the fluid. 5. The fluid actuation system according to claim 1, wherein when a plurality of said pumps are present, an arbitrary pump is appropriately unloaded to control the capacity. Pump displacement control device.