JPS598683B2 - Pressurized fluid supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for supplying pressurized fluid to two circuits, and more particularly to a device for regulating the supply of pressurized fluid in a supply device having at least two constant displacement pumps.

Devices are already known for supplying pressurized fluid to two circuits using a plurality of constant displacement pumps driven by a single diesel engine.

It is generally economically advantageous to choose a diesel engine whose marginal or maximum power is less than the sum of the maximum powers of several pumps.

When the above conditions are combined, it is clear that a device must be provided to limit the power required to drive the pump to below the maximum output value of the engine.

An example of such a system is one in which one or more of the pumps normally supplying each circuit are connected to a fluid tank so that no pressurization occurs.

The connection between the pump outlet and the tank is achieved by controlling the switching valve (or distributor or directional control valve) connected in the discharge pipe, and the switching valve is controlled using the discharge pressure of each circuit. It is done as follows.

However, even with the above-mentioned control scheme, optimum utilization of the power of the diesel engine is not possible, especially when the discharge flow rate of all pumps can be supplied to only one circuit.

SUMMARY OF THE INVENTION An object of the present invention is to provide a new switching valve control system by effectively combining the pressure effects of two circuits, in order to eliminate the drawbacks of the conventional control system described above.

According to this method, the communication state between the discharge port of one pump and the circuit connected thereto is such that, in the case of a conventional device, the pressure in that circuit is such that the discharge port communicates with the fluid tank. Pressure, i.e. “cut-off”
This allows the pressure to be maintained even if the pressure becomes very high.

That is, the present invention is a device for supplying pressurized fluid to two circuits, including a fluid tank, a first constant discharge pump group, a first circuit, and a device included in the first pump group. a first supply conduit connecting the first pump to the first circuit, the first supply conduit being connected to the first supply conduit, the first supply conduit being in communication with the first supply conduit in the first switching position; a first two-way switching valve that communicates a portion of the first supply pipe between the first pump and the fluid tank; a second constant-discharge pump group; a second circuit; a second supply conduit connecting a second pump included in the pump group to the second circuit; and a second supply conduit connected to the second supply conduit and connected to the second supply conduit at a first switching position; a second two-way switching valve that connects a portion of the second supply line between the second pump and the second pump to the fluid tank in a second switching position; and a third two-way switching valve connected between the first switching valve and the second circuit, and connecting the third switching valve to a portion of the first supply pipe between the first switching valve and the first circuit. It consists of a connecting pipe.

The third switching valve communicates the second switching valve with the second circuit in its first switching position, and communicates the second switching valve with the connecting pipe in its second switching position, and also communicates with the second switching valve and the second supply pipe. The section of the circuit that is directly connected to the second circuit is occluded.

First and second control members and a first return member are connected to the first switching valve, each of the first and second control members having an action opposite to that of the first return member;
The first return member acts to maintain the first switching valve in its first switching position.

On the other hand, third and fourth control members and a second return member are connected to the second switching valve, and each of the third and fourth control members has an action opposite to that of the second return member. The second return member acts to maintain the second switching valve in its first switching position.

The above device further includes a first control pipe connecting a portion of the first supply pipe between the first switching valve and the first circuit to the first control member, and a second switching valve of the second supply pipe. A second control pipe connects the portion between the valve and the third switching valve to the second control member, and a second supply pipe connects the portion of the first supply pipe between the first switching valve and the first circuit. an auxiliary conduit connected to a portion of the supply conduit between the second switching valve and the third switching valve; a shuttle valve connected to the auxiliary conduit; and a second switching valve and a third supply conduit. It has a third control conduit that connects the portion between the switching valve and the third control member, and a fourth control conduit that connects the outlet of the shuttle valve to the fourth control member.

Furthermore, the first and second pump groups are coupled to a single prime mover with a maximum output that is less than the sum of the maximum powers of the pumps.

Note that the following configuration is preferable.

That is, each of the first and second control members is a fluid pressure cylinder (also called a jack), and the cross-sectional area ratio of these cylinders is calculated from the total volume value of the first pump group and the total volume of the second pump group. equal to the ratio of the volume value obtained by subtracting the volume of the second pump of the second pump group.

Further, the third and fourth control members are each hydraulic cylinders, and the ratio of the cross-sectional areas of these cylinders is equal to the ratio of the total volumes of the second and first pump groups, respectively.

Hereinafter, the present invention will be described in detail based on embodiments with reference to the accompanying drawings.

The device shown in the figure consists of a single diesel engine 1 and 4
fixed displacement pumps (assuming a predetermined rotational speed, also called constant discharge pumps) 2, 3, 4, 5, a fluid reservoir 6, a first switching valve 7, a second switching valve, both of which are two-position type. It includes a switching valve 8, a third switching valve 9, a first circuit 10, and a second circuit 11.

Drive shafts 12, 13, 14, 15 of pumps 2, 3, 4, 5
The pinions 16, 1γ, 18, and 19 are respectively fixed to rotate integrally therewith.

Further, a pinion 20 is similarly fixed to the output shaft of the engine 1.

Pinion 17 meshes with pinions 16 and 20, and pinion 18 meshes with pinions 19 and 20.

A line 22 connects the first switching valve I to the first circuit 10 , a line 23 connects the first switching valve 7 to the reservoir 6 , and a return line 24 connects the first circuit 10 to the reservoir 6 are doing.

The pump 2 is connected to the reservoir 6 by its suction line 25 and to the line 22 by its discharge line 26.

The pump 3 is connected to the reservoir 6 by its suction pipe 27 and to the first switching valve 7 by its discharge pipe 28 .

The pump 4 is connected to the reservoir 6 by its suction line 29 and to the second switching valve 8 by its discharge line 30.

The second switching valve 8 is then connected to the third switching valve 9 by a line 31, and the second circuit 11 is connected to the reservoir 6 by a return line 32 and to the third switching valve 9 by a line 33. There is.

A conduit 50 connects the second switching valve 8 to the reservoir 6.

The pump 5 is connected to the reservoir 6 by its suction line 34 and to the line 31 by its discharge line 35.

A connecting line 36 connects the third switching valve 9 to the line 22.

The first switching valve 1 has two cylinders (or jacks 38 and 3) with cross-sectional areas S38 and S39, respectively.
9 are connected, and the action of these cylinders is opposite to the action of the first spring 400, which is also connected to the switching valve 7.

These cylinders are connected to lines 22 and 31 by lines 41, 42, respectively.

Similarly, the second switching valve 8 has two cylinders (or jacks) 4 having cross-sectional areas S43 and S44, respectively.
3 and 44 are connected, and the action of these cylinders is controlled by a second spring 450 which is also connected to the switching valve 8.
The action is in the opposite direction.

The pipes 22 and 31 are connected by an auxiliary pipe 46, and a shuttle valve 47 is connected to the auxiliary pipe 46.

Cylinder 44 is connected to the outlet of shuttle valve 47 by line 48, while cylinder 43 is connected to line 31 by line 49.

Then, configure so that the following formula holds true.

S+4/S43-(C2+C3)/(C,
+C3)S38/S39-(c2+Cs)/
c, where C2, C3, C4 and C, are the volumes of pumps 2, 3, 4 and 5, respectively.

As for the first switching valve 7, its first switching position corresponds to the case where the action of the spring 400 predominates over the action of the cylinders 38 and 39, and the lines 22 and 28 are in communication;
The line 23 is closed at the switching valve.

At the second switching position, the pipes 23 and 28 are in communication, and the pipe 22 is closed at the switching valve position.

Regarding the second switching valve 8, the first switching position corresponds to the case where the action of the spring 450 is more dominant than the action of the cylinders 43, 44, the pipes 30 and 31 are in communication, and the pipe 50 is in the switching valve position. occluded in position.

The shuttle valve 47 connects the fluid in the pipes 22 and 31 with the highest pressure to the cylinder? 4.

Such a structure is desirable in order to obtain a high degree of safety in the operation of the device.

That is, according to this structure, if the pressure in either the pipe line 22 or the pipe line 31 is increased, the second switching valve 8 can be switched from its first switching position to its second switching position.

By switching the position of the second switching valve 8, the discharge pipe 3 of the pump 4
0 communicates with the reservoir 6, the driving load on the motor 1 is reduced, and stopping of the motor 1 due to overload can be prevented.

At the second switching position, the pipes 30 and 50 are in communication, and the pipe 31 is closed at the switching valve position.

Regarding the third switching valve 9, at its first switching position, the pipe lines 31 and 33 are in communication, and the pipe line 36 is closed at the position of the switching valve.

At the second switching position, the pipes 31 and 36 are in communication, and the pipe 33 is closed at the switching valve position.

Further, a member 51 for arbitrary control, that is, a member 51 for manual control in this example, is connected to the third switching valve 9.

The third switching valve 9 normally supplies the liquid in the conduit 31 to the circuit 11, but exceptionally it can supply the liquid to the circuit 10 using two different switching valves.
This makes it easy to realize different modes of action.

Note that the maximum power of the engine 1 is less than the sum of the maximum power required to drive the pumps 2, 3, 3, 5.

The graph of FIG. 2 shows the range of variation of the pressure P1o at the inlet of the circuit 10 in the conduit 22 as a function of the pressure P1 at the inlet of the circuit 110 in the conduit 33.

The first two line segments AB and BC that intersect at point B and are parallel to the axis OP1 and the axis OP,o, respectively,
The maximum discharge pressure of 5 is specified.

The pressures pA and PC at points A and C are, for example, 3 2 0
kg/crA.

Further, two other line segments DE and DF parallel to the axis op and the axis OP1o, respectively, intersect at a point D within the area OABC.

Another line segment GH is parallel to line segment 1)F, and the corresponding pressure pH is greater than pF and less than PC.

Furthermore, the axis OP1o and the axis OP1. Two line segments inclined with respect to, namely, line segment JKG extending from line segment AB to point G and point M on line segment BC from point K on line segment JG
There is a line segment KLM extending to .

Note that line segment FD intersects line segment BC at point N, and line segment FD intersects line segment AB at point P.

These several line segments define areas with clear boundaries.

The discharge flow rates of pumps 2, 3, 4, and 5 are Q2 and Q, respectively.
3, Q+, and Q5 correspond to the operating phase described below.

In the conventional system, cylinders 39 and 44 are not present.

In the area EDFO, the first circuit 10 (Q2+03)
is supplied, and (Q4+Q5) is supplied to the second circuit 11 (however, the third switching valve 9 is in the first switching position).

In region AEDP, only Q2 is supplied to the first circuit 10, and (Q4 + Q5) is supplied to the second circuit 11.

In the region NCFD, the first circuit 10 has (Q2 + Qs
) is supplied, and only Q5 is supplied to the second circuit 11.

In the region PDNB, the first circuit 10 is supplied with Q2, and the second circuit 11 is supplied with Q.

The method of the present invention considers line segments JG and KM.

However, these line segments each correspond to the following equations when the third switching valve 9 is set to the second switching position.

That is, for JG, p1ox (Q2 + Q3) + PtI
(Q4+Q5) 1P・・・・・・・・・・・・・
...(1) Also, for KM, P1oX (Q2 +Q3) + Pll ×Q5-P
. . . ”(2) Here, P is the maximum output of the engine 1.

Equation (1) shows that before the discharge path (pipe line 30) of the pump 4 communicates with the reservoir 6 through the second switching valve 8, the pump 2 to
This indicates that the sum of the power (product of pressure and discharge flow rate) of No. 5 is equal to the maximum output P of the engine 1.

Equation (2) shows that even after the discharge passage of pump 4 communicates with reservoir 6, but before the discharge passage of pump 3 communicates with reservoir 6, the sum of the power of pumps 2, 3, and 5 is still This means that it is equal to P.

Ultimately, the method of the present invention is divided into the following three areas.

That is, in the area AJGHO, the first circuit 10 has (Q2
+Q3) is supplied, the second? 11 (Q, +Q5
) is supplied.

In the area HGKMC (i, in the first circuit 10 (Q2 +Q
3) is supplied, and only Q5 is supplied to the second circuit 11.

In area JBMK, Q2 is supplied to the first circuit 10, and Q5 is supplied to the second circuit 11.

If Q3 = Q4 = Q5 and Q2 = 3Qs
, the present invention provides flow and pressure gains in circuits 10 and 11.

That is, regarding the circuit 10, in the conventional method described above, when P1o<PE, the pumps 2 and 3
A flow rate of Q3=4Q3 is supplied, and if pto>PE, a flow rate of Q2=3Q3 is supplied.

On the other hand, in the present invention, Q2 on the lower side of line segment JKL
A flow rate of +Q3=4Q3 is obtained.

That is, in the hatched area AJKLE, the flow rate supplied to the circuit 10 is conventionally 3Q3, but in the present invention it is 4Q3, and therefore the flow rate gain is (4
Q3-3Q3): 3Q3=1/3=33%.

This large flow rate can also be obtained in the region of P1o>PE, and therefore a pressure gain can also be obtained.

On the other hand, regarding the circuit 11, in the conventional system, P1, <pF
In this case, the flow rate is Q4+Q5-2Q5, and P1>pF
In the case of , the pump 4 discharges to the reservoir 6, so the flow rate is Q
It becomes 5.

In contrast, in the present invention, the hatched area DG
In HF, a flow rate of Q4 +Q5= 2Q5 is obtained,
Therefore, the flow rate gain is (2Q5 Q5): Q5=1=
It becomes 100%.

Moreover, this large flow rate is obtained in the region of P11>PF, and therefore a pressure gain is also obtained.

In practice, in order to ensure that the sum of the driving forces of the pumps in all operating situations is equal to the maximum power P of the engine 1 even in the worst case, the conventional scheme requires that the pressures PIO and P1 be adjusted to pE and pF, respectively. However, in the method of the present invention, the line segments JK and KM can be applied to the circuit 10, and the line segment GH can be applied to the circuit 11, so that a large pressure can be applied. area is obtained.

The above equations (1) and (2) can also be modified as follows.

P 10aP1o=A (1)'11 P11+bP1o=B (2) (1)
From formula ' and formula (2)', cylinders 38, 39, 43
The relative values of the cross-sectional areas of and 44 can be easily obtained.

That is, 838/S39-b S44/S43=a becomes.

It will be clear that when the third switching valve 9 is switched to the second switching position (the position shown), the supply by the pump is only to the circuit 10.

Further, generally, before the first switching valve γ causes the discharge passage of the pump 3 to communicate with the reservoir 6, the second switching valve 8 causes the discharge passage of the pump 4 to communicate with the reservoir 6.

This effect can be achieved by selecting the switching valves 7 and 80 control cylinders and springs 40, 450 characteristics.

In summary, for separate supplies to circuits 10 and 11 (
When the third switching valve is in the first switching position, the method of the present invention provides a gain in operating flow rate corresponding to the notched region of the diagram in FIG.

This flow gain in the illustrated example is 33% and 100% for circuits 10 and 11, respectively.

Therefore, by adopting the method of the present invention, the output of the supply device can be greatly increased, and the maximum output value P of the Shikamo engine 1 will not be exceeded.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a feeding device according to the invention. FIG. 2 is a diagram showing the operating state of the device of FIG. 1; [Explanation of symbols], 1... Diesel engine, 2, 3, 4, 5... Pump, 6...
Fluid tank? , 8, 9...... switching valve, 10, 1
1...Circuit, 22, 28, 30, 31, 33
...... Supply pipe line, 36... Connection pipe line, 3
B, 39, 43, 44... Control member, 40, 4
5... Return member, 4L42, 48, 49...
...Control pipe line, 46...゜゜゜Auxiliary pipe line, 47...
...Shuttle valve.

Claims (1)

[Claims] 1. A fluid tank 6, a first constant discharge pump group 2, 3, a first circuit 10, and a first pump 3 for connecting the first pump 3 of the first pump group to the first circuit 10. one supply conduit 28, 22, the first supply conduit 28, 22 is connected to the first supply conduit 28, 22, the first supply conduit is connected in the first switching position, and the first supply conduit is connected in the second switching position. a first two-way switching valve 7 that communicates a portion 28 between the channel and the first pump 3 with the tank 6; a second constant discharge pump group 4, 5; a second circuit 11; a second supply conduit 30, 31, 33 connecting the second pump 4 of the pump group to the second circuit 11; and a second supply conduit connected to the second supply conduit at the first switching position. a second two-way switching valve that connects a portion 30 of the second supply line between the second pump 4 and the tank 6 with the tank 6 in a second switching position; 33, a third two-way switching valve 9 is connected between the second switching valve 8 and the second circuit 11, and the third switching valve 9 is connected to the first switching valve I of the first supply pipe. Portion 22 between the first circuit 10
The third switching valve 9 communicates the second switching valve 8 with the second circuit 11 in its first switching position, and also connects the second switching valve 8 with the second circuit 11 in its second switching position.
The pressurized fluid is supplied to the two circuits 10 and 11, which communicate with the connecting pipe 36 and close the portion 33 of the second supply pipe directly connected to the second circuit 11. In the device, first and second control members 3B, 3 are connected to the first switching valve 7.
9 and a first return member 40, each of said first and second control members exerting an action opposite to that of the first return member, said first return member causing the first switching valve to return to its first position. It does not exert any effect of trying to hold it in the changing position,
Further, third and fourth control members 43 are connected to the second switching valve 8.
, 44 and a second return member 45, each of the third and fourth control members exerting an action opposite to that of the second return member, and the second return member controls the second switching valve. so as to exert an effect of trying to hold it in the first position,
A first control line 41 connects the first supply line 22 between the first switching valve 7 and the first circuit 10 to the first control member 38 , and a second control line 42 connects the first supply line 22 to the first control member 38 . A portion 31 of the second supply line between the second switching valve 8 and the third switching valve 9 is connected to a second control member 39, and an auxiliary line 46 connects the first switching valve 7 of the first supply line. and the first circuit 10 is connected to the portion 31 of the second supply pipe between the second switching valve 8 and the third switching valve 9, and a shuttle valve 47 is provided in the auxiliary pipe. The third control member 43 connects the portion 31 of the second supply pipe between the second switching valve 8 and the third switching valve 9 with the third control pipe 49 .
and is connected to the shuttle valve 4 by a fourth control line 48.
7 is connected to the fourth control member 44, and the pumps 2, 3, 4, 5 of the first and second pump groups are connected to a single pump whose maximum output is smaller than the sum of the maximum powers of the pumps. A pressurized fluid supply device characterized in that it is connected to a driving motor 1.